ISSN 0289-842X

RIKEN
Accelerator
Progress Report
vol.

34

理化学研究所

RIKEN (The Institute of Physical and Chemical Research)

RIKEN Accelerator Progress Report

2000

January-December

vol. 34

1m 11:: ~ :m: ~ PJilIKEN (The Institute of Physical and Chemical Research)

Wako, Saitama, 35J-OJ98 JAPANEditors
T. AbeA. GotoT. Ichihara

K. Ishida

T. Kambara

Y. Kobayashi

A. Ozawa

1. Shimamura

S. Yamaji

Y. Yamazaki

All rights reserved. This report or any part thereof may not be reproduced in any form
(including photostatic or microfilm form) without written permission from the publisher.
All reports are written on authors'responsibility and thus the editors are not liable for thecontents of the report.

CONTENTS
I.

PREFACEII.

OPERATION OF ACCELERATORSPage
1

RILAC Operation ....................................................................

3

RRC and AVF Cyclotron Operations .................................................

5

Operation of the Tandem Accelerator

7

III.

RESEARCH ACTIVITIES

1.

Nuclear Physics
Contribution of the Spin-Orbit Interaction for 1/2+ in Be Isotopes

9

Nuclear Polymer States in C Isotopes .................................................

10

Halo Structure in 19C: A Glauber Model Analysis .....................................

11

Enhancement of Low-Energy Dipole Strength in Light Drip-Line Nuclei

12

Pygmy and Giant Dipole Resonances in Neutron-Rich Nuclei within
the Quasiparticle Representation of the Phonon Damping Model... .. ............... ..

13

Structure of 31 Na Studied by the Monte-Carlo Shell Model. . . . . . . . . . . . . . . . . . . . . . . . . . . .

14

A Search for a Vnified Effective Interaction for Monte-Carlo Shell-Model
Calculations (II) ......................................................................

15

Monte-Carlo Shell Model Calculation for Medium-Heavy Nuclei.. .. ... .. .... ... .......

16

Normal and Super Deformation in 56Ni ...............................................

17

Effects of the Neutron Spin-Orbit Density on the Nuclear Charge Density in
Relativistic Models ...................................................................

18

Analysis of the Matter Distribution of Nuclei with a Gaussian-Basis Expansion. . . . . . . .

19

Microscopic Foundation of the Fermion Dynamical Symmetry Model: 0(6) Limit .....

20

TDHF Calculation of the Excitation of Isoscalar Giant Resonances. . . . . . . . . . . . . . . . . . . .

21

Theoretical Search for Shears Bands in the Arv80 Mass Region ........................

22

Study of Rotational Motion in V nstable Nuclei ........................................

24

Pseudospin Symmetry and Spin Symmetry ............................................

25

Delta-Hole Interaction in Nuclei and the Gamow-Teller (GT) Strength in 90Nb ........

26

Relativistic Hartree-Bogoliubov Approach for Nuclear Matter with Non-Linear
Coupling Terms ......................................................................

27

Extended Renormalized Random-Phase Approximation...............................

28

Exact Form of the Random-Phase Approximation Equation at Finite Temperature
Including the Entropy Effect. . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

29Electromagnetic Cross Sections of Double Giant Dipole Resonances in 136Xe
and 208Pb within the Phonon Damping Model ........................................

30

Angular-Momentum Effect on the Width of the Hot Giant Dipole Resonance within
the Phonon Damping Model..........................................................

31

Thermal Shape and Orientation Fluctuation Corrections for the Hot Giant Dipole
Resonance within the Static Path Approximation .....................................

32

Adiabatic Selfconsistent Collective Coordinate Method for Large-Amplitude
Collective Motion .....................................................................

33

Microscopic Description of Damped Collective Motion ................................

34

Effects of Nuclear Rotation on the Collective Transport Coefficients ...................

35

Fusion Probability for a Multi-Dimensional Dissipative Barrier ........................

36

Dynamics of Contact in 86Kr+208Pb Collisions ........................................

37

New Nuclear Reaction Flow during r-Process Nucleosynthesis in Supernovae:
The Critical Role of Light Neutron-Rich Nuclei .......................................

38

Video: "The Quest for the Origin of the Elements" ...................................

39

Nuclear K Bound States in 3He and 4He ..............................................

40

Empirical Deduction of a Medium-Modified Quark Condensate from Deeply-Bound
Pionic States in Heavy Nuclei. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

41

p-w Mixing in the Oscillation Model ..................................................

43

Deconfinement by an Infinite Potential. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

44

Measurement of Ortho-Para Effect in Muon-Catalyzed dd- Fusion .....................

45

Temperature-Dependence of Muon Catalyzed Fusion in Solid Deuterium andTritium Mixtures .....................................................................

46

Neutron Energy Spectrum from Muon Catalyzed t-t Fusion in a Solid T2 Target.. .. . ..

47

Electron-Nucleus Collider at MUSES .................................................

49

Measurement of the Cross Sections and Analyzing Powers for d-p Elastic Scattering
at Intermediate Energies ..............................................................

50

Measurement of the Polarization Correlation Coefficient for the 3H~( d, P)4He
Reaction ..............................................................................

51

Measurement of the 12C(d, d') Reaction at 270 MeV and a DWIA Analysis Using
the Three-Body dN Interaction .......................................................

53

Study of Neutron-Rich Nuclides Relevant to the Astrophysics R-Process ..............

55

Study of the Secondary Fusion Reaction with the High-Spin Isomer Beam .............

56

Excitation-Energy Dependence of the GDR in Hot 209Bi Nuclei .......................

58

Search for a Z = 118 Superheavy Nucleus in the Reaction of 86Kr with 208Pb .........

60

Superheavy Hydrogen 5H, Spectroscopy of 7He ........................................

61

Observation of an Excited State in 7He with an Unusual Structure ....................

62

Search for Neutron Pair Pre-Emission in the Fusion of 11 Li Halo Nuclei with Si
Target...................... ...... ... ...... ...........................................

63

Sub-Barrier Fusion of 11 Be+ 209 Bi .....................................................

64

2.

Inelastic Alpha-Scattering Reactions on 14 0 and 12Be .................................

65

Measurement of the Magnetic Moment for 15 C ........................................

66

Search for Opposite Deformations of the Proton and Neutron Distributions in 16C

....

67

Electric Quadrupole Moment of 17B ..................................................

68

Determination of the 17 C Ground-State Spin from a g-factor Measurement ............

70

Reaction Cross Sections of 17Ne .......................................................

71

Search for 21 B ........................................................................

72

Coulomb Dissociation of 23 Al .........................................................

73,B-Delayed Proton Decay of 24Si .......................................................

74

Spectroscopy of 34Si with the (d, d') Reaction in Inverse Kinematics ................. . .

75

New Magic Number , N = 16, Near to the Neutron Drip Line. ... ... .. . .. ... ......... ..

76

Deeply Bound Is and 2p States of 1r- in 205Pb

77

Atomic and Solid-State Physics
Charge Transfer in F 2+ Ions Colliding with He Atoms below keY ju Energies
and Its Reverse Process ...............................................................

79

Theoretical Calculation of Double Electron Transfer Processes in Collisions of He 2+
with Mg ..............................................................................

81

Laser-Assisted Formation of Antihydrogen ............................................

82

Effects of the Hyperfine Structure on Symmetric Scattering of Iv1uonic Atoms:
Hyperspherical Close-Coupling Studies. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

83

Possible Binding of Positron with Molecules. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

84

Electron and Positron Scattering from CF3I Molecules below 600 eV ..................

85

Elastic Scattering of Electrons from Carbonyl Sulfide .................................

86

Photoabsorption Spectra in the Continuum of Molecules and Atomic Clusters.. ... ....

87

Radiative Electron Capture of Swift Heavy Ions .......................................

88

Elastic Wave from Fast Heavy-Ion Irradiation of Metals... .. .... ... .. .. . ..... . .. . .. ...

89

Hardening of Fe-Cu Alloys by Swift Heavy Ion Irradiation ............................

90

Magnetic Properties of Fe-Ni Invar Alloys Irradiated by High-Energy Heavy Ions. . . . . .

91

Magnetic Relaxation in Bi-2223 Tapes Irradiated by Xe Ions ..........................

92

Scaling of Irradiation Effects by Primary Ionization Rate in Ion-Irradiated Oxide
Superconductors ......................................................................

93

In-Beam Mossbauer Study on the Jump Mechanism of Self-Interstitials in Pure Iron

94

In-Beam Mossbauer Study on Interstitial and Substitutional 57Mnj57Fe Jumps in Si

96

Depth Profile of Vacancy-Oxygen Pairs in CZ-Si Irradiated with 3.5 GeV-Xe Ions .....

98

Defects and Their Distribution in Si Produced by Ge V-5 7Mn Irradiation ..............

99

Surface Modification on Fe-Ni (31.7at.% Ni) by 3.5 GeV Xe Ion Irradiation..... .. . .. ..

100

Calibration of a Light Particle Telescope for the ALOS Satellite Using a 4He Beam. . . .
Single-Charged Heavy Fragment Ion Production in Fast He 2+ -C Collision ...........

101

Beam Plasma Experiment at RILAC Facility .........................................

103

Vacancy Formation Energy of Indium Determined by Using the Positron
Annihilation Age-Momentum Correlation Technique ....................... .. .........

104

High-Resolution Soft X-Ray Measurements in 2.3 keV lu 15N7+ Ions Transmitted
through a Capillary. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

105

Charge State Distribution of Highly Charged Ions Passing through Microcapillaries

106

Angular Distribution Measurements of Electron Capture Processes for
X 4+(X=C, N, O)-He Collisions at Energy Region below 40 eV lu ......................

108

X-Ray Spectroscopy of Highly Charged Ions Using Superconducting Thnnel
J unction Detector ....................................................................

109

Measurement of Charge State Distributions and Scattering Angular Distributionsof 5 ke V I q Nq+ Ions Transmitted through Microcapillaries for Multiple ElectronTransfer Study .......................................................................

110

Behavior of Ions in Superfluid Helium. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

111

Development of New Technique to Measure Isotope Shift and Hyperfine Shift
Using Atomic Beam Deflector ..... '" ..... ...... ... .... .. ............. ... .. ...... ... ..

112

Development of a High-Intensity Slow-Positron Source for Cooling Highly Charged
Ions II ..... . ..........................................................................

114

Stable, High-Efficiency Positron Moderator with Tungsten Mesh ......................

115

Development of an EBIS Using High-Tc Superconductors .............................

116

A Possibility of a New Stripe Ordered State of Spins and Holes in theOverdoped La2-xSrxCUl-yZny04 Studied by p,SR .. .. ............... .... .......... ...

117

Level Crossing Resonance Study of a Two Dimensional Dimer System SrCu2(B03h ...

118

p,SR Study on Magnetic Properties of p-NPNN·Cu(hfach .............................

119

p,SR Study on a 2D Weak-Ferromagnetic Organic Radical Crystal.... . ... ...... .. . ....

120

First Observation of a Full Dispersion Curve in a Spin-Ladder ........................

121

First Results of Laser Spectroscopy of Antiprotonic Helium at the New Antiproton
Facility AD of CERN.. ...... ... ... .. . .. .... ........... ...... .. . ......... .. . ...... .. ..

123

60

3.

102

Radiochemistry and Nuclear Chemistry

In-Beam Mossbauer Study on Valence States of 57Fe Decaying from 57Mn Implanted
into KMn04 (I) .......................................................................

125

Metabolic Study of Bio-Trace Elements in Pregnant Rats Using the Multitracer
Technique (I) .........................................................................

126

Metabolic Study of Bio-Trace Elements in Pregnant Rats Using the Multitracer
Technique (II) ........................................................................

127

Uptake of Radioactive Elements in Rat Brain Thmor ..................................

128

Metabolic Study of Trace Elements in Se-Excess Rats..... ... ............... ...... ... .

129

4.

In Vivo Multitracer Detection for Assessment of Dynamics of Elements in Liverand Head of Living Rat. ......... ... ...... ... ...... ... ..... .... .. ... .. . ..... ....... ...

130

Alleviation of Cadmium Cytotoxicity by Manganese ..................................

131

Tissue Uptake Behavior of Sc, Mn, Co, Zn, Se and Rb in Mice Bred under
Manganese Deficient and Excessive Diets .............................................

132

Brain Regional Uptake Behavior of Sc, Mn, Co, Zn, Se, and Rb in Mice Fed
Mn-Deficient and Excessive Diets ..................................... ... .............

134

Biobehavior of Multitracers in Brain of 1-, 4- and 8-Day-Old Normal Mice ............

136

Effect of Sodium Iron Ethylendiaminetetraacetic Acid Intake on the Uptake ofTrace Elements in Anemic Rats ............................... .. ......................

137

Study on Distribution of Multitracer in Partially Hepatectomized Rats ................

139

Uptake of Trace Elements in Rat Lens ......................................... ..... ..

140

Effect of Administration Methods of Multitracer Solution on Uptake Rates of Cobalt
and Other Trace Elements in Zn-Deficient Mice .......................................

141

The Absorption of Divalent Cations in Digestive Organs ..............................

143

Influence of Lanthanum on the Uptake of Various Elements by Marigold ..............

145

Chemical Isolation and Purification of 95mTc from Distilled Waste Fraction during
Multitracer Separation of Ag Target ..................................................

147

Synthesis of Chemical Separator for Metals Produced by the Multitracer Method

148

Ion Exchange Separation of Divalent Metal Ions from Iron (III) through
2,2'-Bipyridyl Complex Formation ....................................................

150

Ion-Size-Selective Masking Effect in Metal Ion Separation .............................

151

Multitracer Study on the Diffusion of Various Ions in the Porewater of Granite. . . . . . . .

153

Development of New Multitracer with Neutron Fission of 235U ........................

155

Compton Camera for Multitracer .....................................................

157

Separation of 18F from [18 0] Water by Electrochemical Method

158

Radiation Chemistry and Radiation Biology
Dynamics of Incipient Ion Tracks in Wide-Band-Gap Materials: Electron-Hole
Plasma Luminescence from Ion Tracks and Initiation of Defect Formation.... ........ .

159

Ultrafast Luminescence of CsI Scintillator Crystals under Heavy-Ion Irradiation .......

160

Photoconductivity of Nonconductive Oxides: Search for Electric Conduction underIon Irradiation ........................................................................

161

Recent Progress in Biological Electron Transfer Studies by the Method ofLabelled-Electron with Muons: Cytochrome c Oxidase ................................

162

Metal Uptake Mutant of Yeast Schizosaccharomyces pombe ...........................

164

Influence of Nonpathogenic Fusarium Strains on Uptake of Radionuclides by Tomato..

165

Variation in Sensitivity to Radiation of Orchid Genetic Resources .....................

167

The Effects of Heavy-Ion Beam Irradiation on PLB Development in Several Orchids.. .

168

5.

Mutant Flowers of Dahlia (Dahlia pinnata Cav.) Induced by Heavy-Ion Beams.. ... ...

169

A New Method for Induction of Mutation in Wheat and Barley Using Heavy-Ion
Beams................................................................................

171

Chromosome Breakage in Wheat Induced by Heavy Ion-Beam Irradiation .............

172

Dose-Dependent Effects of Heavy-Ion Beam Irradiation on the Testes of Mice .........

173

Mouse Mutagenesis by Heavy-Ion Beam for the Profiling of Morphogenetic Genes .....

174

Mutation Induction by Heavy-Ion Irradiation of gpt ~ Transgenic Mice ...............

175

Cell-Cycle Arrest Delayed Following Heavy-Ion Exposure .............................

176

Cellular Responses after Low-Dose Exposure to Heavy Ions

177

Instrumentation

Production of Secondary Beam through Rigidity Selection

179

Development of Low Energy Polarized Radioactive Isotope Beams.. .. ... ........... . ..

181

Installation of Low-Energy RI Beam Separator CRIB .................................

183

Installation of a Gas-Filled Recoil Separator (GARIS) at the RIKEN Linear
Accelerator Facility ........ ... .. . .... . .. .. ......... ..... .................. . .. ........ .

184

Absolute Calibration of Deuteron Beam Polarization at Intermediate Energies
via 12C(d, a)10B*(2+) Reaction .......................................................

186

The Design of a Polarimeter for a Spin-Polarized Positron Beam ......................

187

Development of Rotating Target for Big-RIPS in RIBF ...............................

188

Development of Ferromagnetic Targets for Radioactive-Isotope Beams
and a Detector System for Transient Magnetic Field Experiments .....................

190

A Windowless Solid Hydrogen Target. ... .... .. ........... ... .. . .... .. ... .. .... .. .. . ..

191

Construction of Liquid Helium Target. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

193

Construction of a Polarized Proton Target Using a Single Crystal of Aromatic
Molecules .............................................................................

194

Development of Single Crystals of Aromatic Molecules Doped with Pentacene
for a Polarized Proton Target .........................................................

196

Accurate Calibration of 3He Polarization. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

198

Preparation of Single-Crystal C60 for the Implantation of 19F( f - 19 0) ..................

200

RF Deflector System for RI Beams on RIPS ..........................................

201

Development of an RF Ion Guide System .............................................

202

Performance of Liquid Xe Scintillation Chamber with 20Ne Beam .....................

204

Measurement of Depth of Interaction in a Segmented Planar Ge Detector .............

206

Ten-Segment Germanium Detector. . ...... .... . . .. . .......... . .. ......... . .. ... . ... ...

208

Development of Ultrahigh Resolution Time-of-Flight Detector for RI Beam
at RIKEN ............................................................................

209

Detection of Heavy Ions by a Superconducting Thnnel Junction. .... ..... ... . .. ... ....

211

6.

7.

Tritium Gas Handling System Operation in 1999/2000 ................................

212

Optical Detection of Nuclear Spin Precession for the Observation of Nuclear
Casimir Effect in 131 Xe ...............................................................

214

Development of Nuclear Spin Maser for Low Density Spin System.. ..... ....... .. ... ..

215

Calibration of Deuteron Polarimeter DPOL for the Measurement of the 12C( d~ J)
Scattering in Highly Excited Continuum ..............................................

216

Computing Environment of the RIKEN Accelerator Research Facility .................

217

CAMAC Data Acquisition System for the NIRS/HIMAC Facility .. .. .................

219

Development of New Data Acquisition System BabarlDAQ for Nuclear Physics
Experiments. .... .. ... .. ............... ... ... .. .... .. . .. .. ....... .. ... .. ....... ...... .

221

Material Analysis

Fabrication of N anoparticles in Polymer by Ion Implantation

223

Direct Speciation of Sulfur in Marine Sediments by High-Resolution PIXE ............

224

Slow Positron Yields from Some Porous Materials ................................... ..

226

RIKEN-BNL Collaboration on Spin Physics Program

Experimental Activities in the RIKEN BNL Collaboration for Spin Physics at RHIC ..

227

The First RHIC Polarimeter Commissioning ... .... ...................................

229

First Commissioning of the PHENIX Muon Identifier by Au-Au Collision ... ..........

230

PHENIX EMCal: First Results from RHIC Au-Au Collisions .........................

232

RHIC pC CNI Polarimeter............................................................

234

Measurement of the Analyzing Power for Proton-Carbon Elastic Scatteringin the Coulomb-Nuclear Interference Region at 22 GeV / c ..............................

236

Construction of PHENIX South Muon Tracker........................................

237

Performance of the PHENIX EM Cal in First Physics Run .............................

238

Development of a Level-1 Trigger for the PHENIX Central Detector Arms ............

240

Event Reconstruction in the PHENIX Muon Identifier ........ ....... .................

242

Gluon Polarization Measurements in the PHENIX Central Arm....... ...... ...... ....

243

Prospects for Gluon Polarization Measurement with the PHENIX Muon Arms ........

244

Investigating Contact Interaction by Polarized pp Collision ............................

246

Polarized Parton Distribution Functions for Future Predictions. . . . . . . . . . . . . . . . . . . . . . . .

248

Future Transversity Measurements at RHIC ..........................................

249

An Electron-Nucleon/Nucleus Collider at BNL ........................................

251

Computing Center in Japan for RHIC Physics (CC-J) .................................

252

Technique for Huge Data (rv 200TB/year) Storage and Transfer between US
and Japan .................................................................... .. ......

254

Objectivity /DB System at CCJ for the PHENIX Experiment ................ ...... ...

256

Large-Scale Simulation of Au-Au Collision for PHENIX year-I....... ...... .. .... .. . ..

258

Analysis of the PHENIX RICH Detector Using CC-J .................................

259

Hadron Measurement at RHIC/PHENIX .............................................

260

1f0 Acceptance and Efficiency for PHENIX Electromagnetic Calorimeter. . . . . . . . . . . . . . .

261

Theoretical Activity in the RIKEN-BNL Collaboration....... . .. . .... ....... . ..... . .. .

262

Soft-Gluon Effects in Prompt-Photon Production .....................................

263

New Understanding of A Polarization from Unpolarized Scattering ....................

264

Hard QCD and RHIC Spin Physics............ .......................................

265

Single Spin Asymmetries in Inclusive Hadronic Reactions .............................

266

Gluon Distribution in the Real Photon. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

267

Semi-inclusive At Production in Polarized ep Reaction with Polarized Gluons .........

268

Single Diffractive At Productions at Relative Heavy Ion Collider: A Test of Hard
Diffractive Factorization and Polarized Gluon Distribution Function. . . . . . . . . . . . . . . . . . .

269

Polarized s-Quark Distribution in Semi-Inclusive At (At) Production. . . . . . . . . . . . . . . . .

271

Polarized Gluon Distributions from High-PT Pair Charmed Hadron
Leptoproductions .....................................................................

272

Chiral Properties of Domain-Wall Quarks in Quenched QCD ..........................

273

Diquark Correlations and Flavor Dependence of Quark Distributions ..................

274

Renormalization Group Approach to the O(N) Linear Sigma Model at Finite
Temperature ..........................................................................

275

Chiral Condensates in a Light-Cone Vacuum. ........ .... .. ... ... ....... .. .... .. ... ...

276

K ---t 1f1f Decays with Domain Wall Fermions .........................................

277

QCDOC Super Computer for Lattice QCD ...........................................

278

String Tensions and Phase Structure of SU(4) Yang-Mills Theory.....................

279

Domain-Wall Fermion Lattice QCD Calculation of Nucleons ..........................

280

Numerical Lattice Field Theories Using RIKEN VPP Super Computer.. .. . ... ... .. . ..

281

The Spectrum of the QCD Dirac Operator ............................................

282

Parity and CP Violation in Hot QCD .................................................

283

Signature Neutrinos from Ultrahigh-Energy Photons ..................................

284

Light-Front Realization of Chiral Symmetry Breaking .................................

285

Transport Model for Relativistic Nuclear Collisions ...................................

286

Properties of Gluons in Color Superconductors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

287

Phases of QCD at High Baryon Density ...............................................

288

Signals of Hypermatter at RHIC ......................................................

289

Bottom-Up Thermalization in Heavy-Ion Collisions ...................................

290

8.

IV.

Isospin Dense Matter and Quark-Hadron Continuity. .............. .. ... ......... .....

291

An Effective Theory of Nuclear Matter ................................................

292

Looking for a Colored Glass Condensate in High Energy Collisions ....................

293

Leading Local Operator Analysis of <P' ---t <P7r7r Processes

294

Miscellaneous

Topological Modes of Solidification in Liquids with a Confined Geometry. . . . . . . . . . . . . .

295

Possible Mobile TeV Muon Source for Disasters Prevention

297

NUCLEAR DATA

Measurement of Neutron Production Cross Sections by High-Energy Heavy Ions
V.

299

DEVELOPMENT OF ACCELERATOR FACILITIESRI Beam Factory Project: Progress Report ...........................................

301

Dependence of Beam Intensity on Plasma Electrode Size and Position
for RIKEN 18 GHz Electron Cyclotron Resonance Ion Source .........................

303

Investigation of Bias Disk Effect in RIKEN 18 GHz ECRIS under the Pulsed Mode
Operation of Bias Voltage ............................................................

305

Status of Liquid He Free Super Conducting Electron Cyclotron Resonance Ion
Source................................................................................

307

Plasma Measurements on the Pulsed High-Power Microwave Ion Source at RIKEN ....

309

First Beam Measurement of Laser Ion Source at RIKEN ..............................

311

Development of Long-Lived Carbon Foil for Charge Stripper in RILAC ...............

313

Development of Liquid Film Charge Stripper ..........................................

315

Construction of a Test Cavity for Sliding Rf Contacts .................................

316

New Control System for the RIKEN Ring Cyclotron Using EPICS ....................

318

CORBA-EPICS Server ............................. . .................................

320

Construction of the High-Energy Part of the CSM ....................................

322

Indication System for Charge-State Multiplier Resonator Voltage .....................

324

Compact Beam Diagnostic System for CSM ...........................................

325

New Beam Transport System of RILAC ....................................... . ......

327

Dipole and Quadrupole Magnets for Beam Transport System of RIKEN Heavy-Ion
Linac and RI Beam Factory ..........................................................

329

Construction of the IRC for RIKEN RI Beam Factory ................................

331

Magnetic Field Measurement of the IRC Sector Magnets ..............................

333

Construction of the rf-Resonator for the RIKEN Intermediate-Stage Ring Cyclotron ...

335

Status of the SRC for the RIKEN RI Beam Factory ...................................

337

Design of Sector Magnets for Superconducting Ring Cyclotron ........................

339

VI.

Design of the Injection and Extraction Systems for the RIKEN Superconducting
Ring Cyclotron .................................................... . ..................

341

Design of Superconducting Bending Magnet for Superconducting Ring Cyclotron. .....

343

Measurement of Outgassing Rates of Materials Used in the Vacuum Chamber for
RIKEN Superconducting Ring Cyclotron and Intermediate Ring Cyclotron.. ... . ......

345

Helium Cooling System of the RIKEN Superconducting Ring Cyclotron.... .... ..... ..

347

New Liquid Helium Supply and Recovery System .....................................

349

Prototype of Superferric Quadrupole Magnets for the BigRIPS Separator (I) ..........

350

Prototype of Superferric Quadrupole Magnets for the BigRIPS Separator (II) .........

353

Pulsing Magnet Power Supply for the RIKEN RI-Beam Factory Project... .. .... .. ... .

355

New Lattice Design of ACR for MUSES ..............................................

357

Space-Charge-Dominated Ion Beams Cooled by Electron Cooling ....... . . . . . . . . . . . . . . .

360

Development of the Kicker Magnet for MUSES .......................................

362

Ferrite Evaluation Test for MUSES ...................................................

364

Helical Partial Snake Magnet for AGS

365

RADIATION MONITORING

Routine Work for Radiation Safety in the Ring Cyclotron Facility. . . . . . . . . . . . . . . . . . . . .

367

Improvement of Drain System in the Ring Cyclotron Facility.... . . .. . . .. . ..... . . ... ...

369

VII.

LIST OF PUBLICATIONS ...............................................................

371

VIII.

LIST OF PREPRINTS ...................................................................

380

IX.

PAPERS PRESENTED AT MEETINGS ..................................................

383

X.

LIST OF SYMPOSIA

399

XI.

LIST OF SEMINARS

401

XII.

LIST OF PERSONNEL

408

AUTHOR INDEXRIKEN Accel. Prog. Rep. 34 (2001)

I. PREFACE

This issue of RIKEN Accelerator Progress Reportreports research activities of the RIKEN Accelerator
Research Facility (RARF) during the calendar year of
2000. The research programs have been coordinatedin the framework of the project entitled Multidisciplinary Researches on Heavy Ion Science. The project
involves a variety of fields such as: nuclear physics,
atomic physics, nuclear chemistry, radiation biology,
condensed matter physics in terms of accelerator orradiation application, basic studies on energy production, basic studies on plants mutation using heavy-ion
beams, material characterization, application to spacescience, accelerator physics and engineering, laser technology, and computational technology. The construction of main cyclotron building of RI Beam Factory has
been started this year. These activities involved 12laboratories in RIKEN , RBRC (RIKEN-Brookhaven
Research Center at Brookhaven National Laboratory),and more than 300 researchers including users fromdomestic and foreign institutions. Thirty-six universities and institutes from within Japan and 33 institutes
from 10 countries are included.
Major research activities of the RARF are basedon the heavy-ion accelerator complex consists of theK = 540 Me V RIKEN Ring Cyclotron (RRC) and theenergy-variable heavy-ion linear accelerator (RILAC)
and the K = 70 MeV azimuthally variable field cyclotron (AVF) , which have altogether provided a beamtime (on the target) of more than 4000 hours throughthe year. Those statistic numbers are slightly shorter
than those of previous years because of the planned
shutdown due to the construction-program of RI Beam
Factory.
The .three accelerators deliver heavy-ion beams ofa variety of elements with energies ranging from a few
A MeV to 135A MeV. The two-injector machines (AVF
and RILAC) are equipped with ECR heavy ion sources.
The AVF is additionally equipped with a polarized ion
source for vector and tensor polarized deuterons. The
three accelerators have been used in various configurations. The RRC operate with the AVF or the RILAC
as the injector. The AVF has been providing beams
of ions of mass number up to 60 and the RILAC has
been providing beams of ions of mass number larger
than that. In addition, the AVF and the RILAC wereused separately, when they are not used as the injector, for low energy applications. Recently, low energy(5A MeV) beam of 84Kr has been accelerated for the
study of superheavy elements. The beam current ashigh as 0.8 particle J.LA was delivered on the target.
Two thirds of the RRC research beam time (",3500

hours in total) goes to nuclear physics and one third is. used by atomic physics, material science, nuclear chemistry, radiation biology and others. While the RILAC
and the AVF beam time were used for fields other than
nuclear physics. The research beam time at the AVF
is 2100 hours and 800 hours at the RILAC. RILAC
beam time was very little because of the constructionof booster linac for charge stripping used in RIBF.
The use of radioactive-ion (RI) beams is the mainemphasis of the science at the RRC. Major subjects
pursued are: (1) exotic nuclear structure and new dynamics of extremely neutron-rich nuclei (such as thosewith a neutron halo or skin) , (2) nuclear astrophysics
involving unstable-nucleus reactions, (3) synthesis of
new unstable isotopes far from the valley of stability,(4) extensive measurements of nuclear moments. Characteristic features of intermediate-energy direct reactions are often exploited for such studies.
One of the highlights in nuclear physics is a discovery of a new magic number N = 16. It is the firstmagic number that appears only in neutron-rich nuclei. The another success was the use of secondary
beam for another fragmentation reaction and the observation of ,-rays from very neutron rich nuclei, forexample 36S. New determination of magnetic moments(15C , 17C) and a quadrupole moment (17B) of neutronrich nuclei continue steadily. An experiment on the
production of superheavy elements has been restarted
using G AIRIS spectrometer. This spectrometer is being moved to RILAC experimental room. Experimentswith higher intensity beam (up to 10 particle J.LA) areplanned in near future . In theory, outstanding results
have been obtained and continue to coming out fromMonte-Carlo Shell model calculations. Many properties of nuclei far from the stability lines have been correctly predicted using Alphleet parallel computer in
RARF. The study of polymer states with alpha clusters and loosely bound neutrons are of special interest.
Starting this issue, contributions are presented fromthe RBRC. The RBRC has been established in 1997
for study of high-energy nuclear physics. In theory
group, non-parturbative QCD studies are the central
subject. In experimental group, the construction ofexperimental system (PHENIX) as well as the Siberiansnake at the relativistic heavy ion collider (RHIC) areclose to completion. The origin of nucleon spin is themain subject of the study.
The RI beams were useful for other domains of science as well. In particular, application to condensed
matter science has been developed to a large extent by
exploiting on-line capability of Mossbauer and PAC

1

spectroscopies that are feasible only with RI beams.
Intermediate-energy heavy ions from the RRC havefound their own applicability. A strikingly efficient mutagenic effect has been observed when the embryo ofa Tobacco plant is shot by heavy ions. High-energy
heavy ions were irradiated to the plants naturally
placed in the air for desirable amount of LET throughsample. It has opened a new scheme of mutant production that is efficient and well controlled. The method
is so efficient that it is expected to offer new possibilities of bioscience research through comparison between
normal and mutagenic samples. For more detailed information such as cross talks between cells is planned
to be studied by developing a micro beam.
The RARF carries many international collaborations, among them are large-size two internationalcollaboration programs using overseas accelerator facilities: one is the muon science project at ISIS in collaboration with the Ratherford-Appleton Laboratory

2(RAL), and another is the spin physics program at
RHIC in collaboration with the Brookhaven National
Laboratory (BNL). The pulsed muon beam facility at
ISIS has been operated steadily. At RHIC facility,
the first heavy-ion beam and the first polarized proton beams have been successfully accelerated. Studies
of quark-gluon spin structure functions at BNL/RHIC
are waiting for the commissioning of RHIC operation
early next year. The large computer system for the
analysis (CC-J) has been installed in Wako site.
The RI beam factory project is going reasonably
fast. Ground has been broken for the facility building.

1. Tanihata
Director
RIKEN Accelerator Research Facility

II. OPERATION OF ACCELERATORSRIKEN Accel. Prog. Rep. 34 (2001)

RILAC Operation
E. Ikezawa, M. Kase, A. Goto , S. Kohara, M. Fujimaki, O. Kamigaito, N. Fukunishi, Y. Miyazawa, T. Aihara,*
T. Ohki,* H. Hasebe,* H. Yamauchi,* and Y. Yano
The upgrade of RILAC began in the spring of 2000
as a result of collaboration with the Center of Nuclear Science (CNS) of Tokyo University. For installation works, regular RILAC operation was discontinued from Aprill through November 30,2000. Figure 1
shows the layout of RILAC.
We carried out the following installation works.
(1) A shield door and a part of the wall between theNo. 1 and No.2 target rooms of RILAC were dismantled in June of 2000. The target rooms were modified.
A new beam transport line to the RIKEN Ring Cyclotron (RRC) and five new target lines were installedin the target rooms.
(2) The seven resonators of a Charge-State Multiplier system (CSM) were installed after the existing
accelerator of RILAC. The first two acceleration resonators and the last deceleration resonator of theseare of variable-frequency type. Their frequency tunable range is 36 to 78 MHz. The other four acceleration resonators are operated only at the frequency of
76 MHz. The maximum energy of RILAC using the
CSM will be 6 MeV jnucleon. Therefore, the radiation
safety control system of RILAC will be replaced witha new one.
(3) A GAs-filled Recoil Isotope Separator (GARIS)
was moved from the El experiment room of RRC to

the No.1 target room of RILAC.
(4) A 90° bending magnet , a switching magnet (0°,30°, and 60°), and an 85° bending magnet were fabricated. The three new magnets and the two existing
60° bending magnets were installed in the target rooms
after the CSM in September of 2000.
(5) Four compact quadrupole triplet magnets witha field gradient of 25 T jm and their power supplies
were fabricated. The new magnets, which have alsofunction as steering magnets , were installed in a narrow space between two resonators of the CSM. Each
new magnet power supply has a GPIB interface module, and is connected to the Ethernet LAN through a
LAN jHP-IB Gateway E2050.
(6) A new deionizer watercooling system was installed in September of 2000. The cooling capacity is
1.3 MW. This system has been used for the CSM, forquadrupole triplet magnets, and for the power suppliesof the magnets.
From January through March, RILAC was in steady
operation and supplied various kinds of ion beams forvarious experiments. Table 1 presents the statistics of
RILAC operation in 2000. One day of scheduled beamtime was forced to be cancelled owing to the failure ofan rf feeder in the No.5 resonator. The days taken
for the overhaul and improvement, as shown in Ta-

No.1 Target room
6.3m

6.3m

6.3 m

6.3m

6.3m

No.2

No. 1

Control room

4

E

Target line

Target line

11.8SmExisting accelerator!

- __ - - ________ - - - - __ - - - - - - - - - - - - - - - _____ - ____ - - ________ - - ___ - - - - - - - - - - - __ I

CSM A l-A6, Dl
No.2 Target room
Fig. 1. The layout of RILAC. The CSM AI-A6 are the six acceleration resonators of the CSM. The
CSM D1 is a deceleration resonator of the CSM.
SRI Accelerator Service, Ltd.

3

Table 1. Statistics for RILAC operation from January 1
through December 31, 2000.
Days%

Beam time

52

14.2

Overhaul and improvement

194

53.0

Periodic inspection and repair

IO

2.7

Scheduled shutdown

109

29 .8

Total

366

100

Machine trouble

0.3

Table 2. Beam time allocated for different research groups.

Ion

Mass

He

4
7
12
14
20
40
84

Li
C
N
Ne
Ar
Kr

%

Ion

Mass

Atomic physics

4

7.7

0

Radiation chemistry

Il

21.2

Material analysis and development

4

7.7

Accelerator research

2

3.8

Beam transport to RRC

31

59 .6

Ar
Ni
Kr
Kr
Xe
Ta

16
40
58
84
86
136
181

52

100

ble 1, include 165 days of installation works. Table 2
summarizes the number of days allotted to different
research groups. The percentage of beam time usedby the RRC group was approximately 60% of the total. The 7Li, 58Ni, 84Kr, 86Kr, 136Xe, and 181Ta ionsaccelerated by RILAC were injected to RRC. Tables 3
and 4 present the statistics of the RILAC ion beams
delivered using a Cockcroft-Walton injector with an
8 GHz ECR ion source (NEOMAFIOS) and those delivered using a variable-frequency RFQ with an 18 GHz
ECR ion source, respectively. Ion beams of 12 elements
were used for the experiments and beam acceleration
tests. The percentage of beam time using metallic ionsamounted to approximately 19% of the total.

Charge states
1,2
1,2
4
4
4
8
13
Total

Days
7
4
I
4
I
2
I
20

Table 4. Statistics of the RILAC ion beams delivered using a variable-frequency RFQ with an 18 GHz ECR ion
source.

Days

Total

4

Table 3. Statistics of the RILAC ion beams delivered usinga Cockcroft-Walton injector with an 8 GHz ECR ion
source.

Charge states
4
8
9
17
10
20
16,24
Total

Days
2

16
4
3
32

We experienced the following machine troubles during this reporting period.
(1) The cooling pipes in the rf feeder of the No.5
resonator melted due to too high rf currents. This
problem occurred at the acceleration frequency of
25.4 MHz.
(2) Two quadrupole magnets in the drift tube (DT11 and DT2-17) of the No.1 and No.2 resonators suffered insulation failure in their tape coils and the beam
was accelerated without these magnets excited during
the operation of RILAC. The magnets and the drift
tubes will be replaced with new ones in the upcomingyear.

RIKEN Aeeei. Prog. Rep. 34 (2001)

RRC and AVF Cyclotron Operations
M. Kase, A. Goto, S. Numata, T. Kageyama, M. Nagase, S. Kohara, T. Nakagawa, K. Ikegami , J. Fujita,
O. Kamigaito, M. Kidera, M. Komiyama, A. Yoneda, 1. Yokoyama, H. Isshiki,* H. Akagi,* R. Abe,*N. Tsukiori,* K. Takahashi,* T. Maie,* R. Ohta,* K. Kobayashi,* M. Nishida,* and Y. Yano
Statistics of the RRC operation during the year 2000
are shown in Table 1. The total operation time for the
RRC was 5840 hours and of these, 4440 hours werespent for experiments. The history of the RRC operation for these fourteen years is shown in Fig. 1. The operations of RRC and AVF were interrupted frequently
due to the rearrangement of experimental apparatus
and beam lines from April to December 2000. Moreover, since RILAC has been stopped since April 2000
due to an energy upgrade program using CSM (Charge
State Multiplier), RILAC-RRC operation was limited
to 8% of the total operation. Nevertheless, operationof the RRC during the year 2000 was carried out efficiently and steadily, as shown in Fig. 1.

Table 1. Statistics of RRC Operation in 2000.
5840 hr
4440 hrOperation Time of RRC
Beam Service Time
Nuclear Physics Experiment
Non-Nuclear Physics Experiment

84%
16%

RILAC-RRC Operation
AVF-RRC Operation

92%(Hours)
9000

8%

/F
I

8000
7000

~

~F

I

6000

.:y ~\ '''c

5000;/41': ...-B

4000
3000

2000
1000

o

~/

1\ >:

~

,~il
1988

:(11

II

...-A

II
1990

1992 1994 1996

1998

2000 (Year)

Fig. 1. History of the RRC operation for fourteen years
from 1987 to 2000. A: nuclear physics experiments, B:
non-nuclear physics experiments, C: beam-tuning time,
D: unscheduled shutdown due to machine trouble, E:
holidays and maintenance, and F: scheduled shutdown
due to construction work.

In a collaboration between RIKEN and the Centerof Nuclear Science (CNS) of Tokyo University, many
rearrangements of RARF (the RIKEN Accelerator Research Facility) were carried out in 2000. Two large
experimental apparatuses were newly imported fromoutside of RIKEN. A spectrometer (CRIB) was installed in the E7 target room ((a) in Fig. 2) and theparticle analyzer (PA) was installed in the E2 target
room ((b) in Fig. 2). In order to make space for theselarge apparatuses, some old beam lines in RARF were
removed simultaneously. The ASCHRA chamber inthe E2A beam course was moved out of the beam line
and stored in the corner of the E2 target room ((c)
in Fig. 2) for future use. The slow-beam apparatus in
E7B were scrapped and the beam lines from RRC to
the E7 target room were removed completely. Hereafter, E7 is used only for beams directly from AVF.
The construction of new beam transport lines, which
directly connect AVF with the present beam lines of
RRC, was started in the summer 2000 and will be completed in the spring 2001 ((d) in Fig. 2). It ensuresthat the stand-alone use of AVF will be extended to allpresent beam lines of RARF during future operationof RIBF. A rotational bending magnet was installed in
the injection beam line of AVF at the end of 2000 andhence the switching of several ion sources becomes possible. In 2001 , three sets of ECR ion sources for AVF
injection will be arranged around this magnet in theion source room. Therefore, the time which is spentfor changing the beam at an ion source will be saved
in many cases and the development regarding the ion
source 'will be done easily.
The beam courses in the El target room were alsochanged drastically in 2000. The GARIS in the EIA
beam course was transferred to the RILAC target
room. Although research on superheavy elements with ·GARIS is still possible in EIA for the next two years
until the RIBF will start, a more efficient use of heavyion beams for the research is expected in RILAC after its energy is upgraded using six acceleration cavities of CSM. While the AVF-RRC operation is andwill be dominated until the RIBF starts, the superheavy experiment become available by stand-alone useof RILAC. A new bending magnet was moved to the
El target room in advance, which will be used in thetransport line from RRC to RIBF in the future. The
EIC beam course was improved as the test course of
RIPS. For example, a detector test for RIPS using
a secondary beam is now available in the EIC beamcourse ((e) in Fig. 2).

SRI Accelerator Service, Ltd.

5

(a)

(d)

(b)

(e) -;--+--_~..

(c)Fig. 2. Layout of beam lines of the RRC and AVF. See text for (a), (b), (c), (d) , and (e).

Last spring (2000) , the cables of RRC sector magnets were found to be partially damaged after a long
operation of fourteen years. Their insulation cover became very hard and lost its flexibility. Some parts ofthem cracked and a copper conductor was exposed in
the worst case. Last summer (2000), the cables werepartially replaced by a new type of cable (type: WL1)
which can withstand higher temperatures and maintain the same flexibility compared to the former ones.
In order to reproduce the isochronous magnetic fieldof RRC more easily, a new power supply was added to6

one of the trim coils (# 11- 12) , which had been su pplied with a dc current by one power supply in series with another trim coil (#18- 19). As a result , theflexibility of the combination of trim coil currents wasenhanced. The new power supply with a maximum
current of 300 A is very compact , because the switching mode regulation was applied for the first time in
the present facilities. This type of dc power supply isgoing to be used very widely in IRC as well as SRC of
the RIBF project which is now under construction.

RIKEN Accel. Prog. Rep. 34 (2001)

Operation of the Tandem Accelerator
K. Ogiwara, T. Urai , K. Watanabe, and E. Yagi
The 1. 7 MeV tandem accelerator was operated for
98 days in total for experiments, except for the machine inspection and a beam test, during the annual
reporting period from Nov. 1, 1999 to Oct. 31, 2000.
For the cesium-sputter ion source, a new type of ionizer was used. However, after a few cycles of operation,
it no longer functioned because of a reduction in theelectric power supplied to the sheath heater of the ionizer. Through various test operations it was clarified
that the trouble resulted from an electrical short circuit
which formed between the heater wire and its sheathdue to the condensation of cesium from its vapour.
Therefore, by covering the end of the sheath heaterwith insulating ceramics, the functioning of the ionizer
was restored. The tandem machine has been operated
without any other serious problems as it was before
transfer to the present experimental hall.
Experimental studies on the following subjects havebeen performed, and some are still in progress.

(1) Rutherford backscattering spectroscopy (RBS).
(a) Behaviour of Xe atoms implanted into iron.
(b) Channelling analysis of dopants in semiconducting materials.
(c) RBS analysis of polystyrene surfaces and glassy
carbon films modified by ion implantation.
(2) Nuclear reaction analysis (NRA).
(a) Lattice location of hydrogen in niobium alloys
by means of the channelling method.
(3) Particle-induced X-ray emission (PIXE) .
(a) Application of the PIXE method in biomedical
and materials sciences: Trace element analysis using
energy-dispersive X-ray spectrometry.
(b) Trace element analysis of feathers to monitor
environmental pollution.
(c) Development of an in-air high-resolution PIXE
system for chemical state analysis.
(d) Characterization of the II-VI ternary semiconducting crystals.

7

8

III. RESEARCH ACTIVITIES1. Nuclear Physics

RIKEN Accel. Prog. Rep. 34 (2001)

Contribution of the Spin-Orbit Interaction for 1/2+ in Be Isotopes
N. Itagaki, *1 S. Okabe, *2 and K. Ikeda[Cluster structure, Light neutron-rich nuclei]
A shift of the closed-shell structure is a characteristic
behavior of systems with weakly bound neutrons. The
contributions of the 3d shell have been analyzed in N =8 nuclei. For example, a calculation has shown thatthe slow {1-decay of 12Be to 12B can be explained byan admixture of the sd shell in 12Be (N = 8) in which
the closed p-shell component must be less than 30%.
This shows that the concept of magic numbers is vague
in 12Be.
The main purpose of this work is to show the mechanism for the appearance of this (1/2+)2 configuration
in low-lying energy in detail , not only in 12Be, but also
in other Be isotopes. According to our previous results for lOBe,l) the dominant configuration of the twovalence neutrons for the second 0+ state is (1/2+)2,
and the level inversion between 1/2- and 1/2+ in 9Be
also holds in lOBe. Here, the two valence neutrons
stay along the (X-(X axis, and reduce the kinetic energy
by enhancing the (X-(X distance (up to around 4 fm).
Therefore, the 1/2+ orbit in this case is not a sphericals-wave, but a polarized orbit with the d-wave component.
If the 1/2+ state consists of the pure s-orbit, naturally there is no contribution of the spin-orbit interaction. In Be isotopes , the state contains the dorbit component. However, the spin-orbit interaction
again vanishes, when the two valence neutrons arelocated along the (X - (X axis, since two neutrons withthe same spatial distribution construct only the spinsinglet state. This has been the situation in tradi:"tional molecular-orbital (MO) models. However, when
one of the valence neutrons deviates from the (X-(Xaxis, the spin-triplet state can be constructed, and thespin-orbit interaction strongly acts between this state
and the original (1/2+)2 configuration with the spinsinglet. An extension of the model space also enables
us to improve the description of the neutron tail. We
have estimated the reduction of the kinetic energy due
to the improvement of the neutron tail.
The total wave function is fully antisymmetrized andexpressed by a superposition of terms centered at different relative distances between the two (X clusters
with various configurations of the valence neutrons.
All nucleons are described by Gaussians with the oscillator parameter (b) equal to 1.46 fm.
GR =(~) ~ exp[-v(f' - R],(1)

expressed by a linear combination of local Gaussians
based on the MO picture ,¢ciXci = ~gjGR~XCi .

The effective nucleon-nucleon interaction is Volkov No.
2 for the central part and the G3RS spin-orbit term forthe spin-orbit part; all parameters are determined fromthe (X + n and (X + (X scattering phase shifts and thebinding energy of the deuteron.
At first, we discuss the contribution of the spin-orbit
interaction for the second 0+ state of lOBe. The calculated 0+ energy shows that the smaller is the (X-(Xdistance, the larger is the contribution of the couplingwith the spin-triplet state. When the (X-(X distance is
5 fm, the coupling of S = 1 to the original (1/2+)2 increases the binding energy by about 3 MeV; however,when the (X -(X distance is 3 fm , the coupling increases
the binding energy by about 4.5 MeV. Therefore, thecoupling with the spin-triplet becomes stronger as the(X-(X distance becomes small.
Next, the large contribution of this spin-orbit interaction is discussed concerning 12Be. 2) In 12Be, fourvalence neutrons rotate around two (X clusters and,mainly, two configurations are important for the 0+
ground state. One is (3/2-)2 (1/2-)2 for the four valence neutrons, which corresponds to the closed p-shell
configuration of the neutrons at the zero limit of the (X(X distance. The other configuration is (3/2-)2 (1/2+)2,
where two of the four valence neutrons occupy theO"-orbit. It is necessary to compare the energy ofthese two configurations as a function of the (X-(Xdistance. When it is small, for example 2 fm, thedominant configuration of the four valence neutronsis (3/2-)2(1/2 - )2 for the ground state, which corresponds to the closed p-shell configuration at the limitof the (X-(X distance, zero. On the other hand, the(3/2-)2(1/2+)2 configuration for the four valence neutrons becomes lower as the (X-(X distance is increased.
Due to the spin-orbit coupling, the energy is almost thesame as that of (3/2 - ) 2(1/2 - ) 2, corresponding to theclosed p-shell configuration. Furthermore, the energyof (3/2-)2(1/2+)2 is suggested to become even lower
than (3/2-)2(1/2-)2 when the pairing effect between(3/2-)2 and (1/2-)2 is taken into account . These effects play crucial roles in accounting for breaking of
the N = 8 magic number.

Each valence neutron (¢ciXci ) around the (X-(X core is

References* 1 Department of Physics, U riiversity of Tokyo

1) N. Itagaki et al.: Phys. Rev. C 61 , 044306 (2000).
2) N. Itagaki et al.: Phys. Rev. C 62, 034301 (2000).

*2 Center for Information Multimedia Studies, Hokkaido Univ.

(2)

j

9

RIKEN Accel. Prog. Rep. 34 (2001)

Nuclear Polymer States in C Isotopes
N. Itagaki, *1 S. Okabe, *2 K. Ikeda, and 1. Tanihata[Cluster structure, Neutron-rich nuclei]
A survey of the molecular-like structure is one of themost challenging subjects in light neutron-rich nuclei.
In Be isotopes, recently, decay into fragments of He
isotopes (4He, 6He, 8He) has been observed from theexcited states of lOBe and 12Be, and the presence of a
two-center configuration is suggested. From the theoretical side, these states are studied by various models
by which molecular-orbital (MO) nature of the weakly
bound neutrons around the two a-clusters has been
revealed. 1,2) As for multi-cluster configurations in light
a-nuclei beyond the two-center systems, the existenceof N a states has been predicted around the thresholdenergy in the so-called Ikeda diagram. For example, it
has been suggested that the second 0+ state of 12C has
a 3a-like molecular configuration. However, according
to many theoretical analyses, the state is not necessary to have a linear-chain of 3a, but is described asa weak-coupling state with a triangular shape or the
8Be+a configuration.
In this work, the MO approach introduced for the Be
isotopes is applied to a study of C isotopes. The stability of the linear-chain states against the breathing-like
path and the bending-like path are shown to be increased by adding valence neutrons around a 3a core.
Two orbitals are introduced based on MO: when the
distribution of the neutron is perpendicular to the 3aaxis, it is called 7r-orbit: if it is along the axis, it iscalled a O"-orbit corresponding to a higher nodal orbital.
We start with the stability of the linear-chain statesagainst the breathing-like path. The relative distance
between a-clusters is expressed by the parameter d. If
there are no valence neutrons, although the 3a-system
2C) has minimal energy at around d = 3.5 fm , theenergy pocket is too shallow to conclude the stabilityof the linear-chain state. On the contrary, in 14C withtwo valence neutrons in 3/2;, there appears to be evident minimal energy at around d = 3 fm. The energy(('-.; -82 MeV) is lower than 12C by 11 MeV and also theenergy pocket is much deeper. Therefore, the 7r-orbit
is found to stabilize the linear-chain structure and toprevent a breathing-like break-up of the system. This
14C(3/2;)2 configuration corresponds to an excitationenergy of 18 MeV from the ground state, which is calculated by introducing a MO around the 3a-core withan equilateral-triangle configuration. In the case of theO"-orbit for the two valence neutrons 4 C(I/2;;)2), theexcitation energy is higher by about 14 MeV in comparison with 14C(3/2;)2. It is rather surprising thatthe difference is only 14 MeV in spite of the fact that

e

e

*1
*2

10

Department of Physics, University of Tokyo
Center for Information Multimedia Studies, Hokkaido Univ.

3/2; has only one node and 1/2;; has three nodes.
This is due to the a-a-a clustering of the core. The
higher nodal orbits along the symmetry axis (O"-orbit)
become low-lying as a result of the clustering.
We have shown that 14C(3/2;)2 is stable against
the breathing-like path. Next, the stability against
the bending motion is examined. The curvature of the0+ energy against the bending angle is rather monotonic and the energy minimum does not clearly appear. This situation does not drastically change even
if the orthogonality between the linear-chain configuration and low-lying states with the equilateral triangle 3a-configuration is taken into account. This effectworks, but not sufficiently to push up the energy of thestate with a finite bending angle.
The 3a linear-chain state of 14C with two valence
neutrons in the 7r-orbit is found to be stable against
the breathing-path, but not stable against the bendingpath. Therefore, we next increase the number of thevalence neutrons and survey the stability of the linearchain state in 16C based on the a + a + a + 4n
model. The lowest configuration for the four valence neutrons is (3/2;)2(1/2;)2, where all of thevalence neutrons occupy the 7r-orbits. The 0+ energy curve of 16C((3/2;)2(1/2;)2) shows an energy
pocket at -86 MeV around d = 2.5- 3.0 fm , which is
deep enough for stability against the breathing-like
path. However, 16C((3/2;)2(1/2;)2) does not haveany minimal energy against the bending-like path.
Next, two of the valence neutrons are introduced tooccupy the O"-orbit, and 16C((3/2;)2(1/2;;)2) is also
found to be stable against the breathing-like path.
The minimal 0+ energy is higher by 5 MeV than
16C((3/2;)2(1/2;)2) , and the excitation energy corresponds to ('-.;25 MeV. The rotation band of this linearchain states has an energy slope of ~; = 150 ke V. Furthermore, 16C( (3/2;)2 (1/2;; )2) is also stable against
the bending-like path, since there appears a sharp increase of the 0+ energy against the bending angle.
This feature is much different from 14C((3/2;)2) and16C( (3/2;)2 (1/2; )2).
In summary, the configuration of valence neutrons
consisting of combination of the 7r- and the O"-orbit
is promising to stabilize the linear-chain state. The
excited state in 16C is one candidate.
References
1) N. Itagaki and S. Okabe: Phys. Rev. C 61 , 044306(2000).
2) N. Itagaki, S. Okabe, and I. Ikeda: Phys. Rev. C 62,
034301 (2000).

RIKEN Accel. Prog. Rep. 34 (2001)

Halo Structure in 19C: A Glauber Model Analysist
R. Kanungo, 1. Tanihata, Y. Ogawa,*l H. Toki,*2 and A. Ozawa[Halo, Glauber model]
The recently available 19C + 12C interaction crosssection data at Elab = 960A MeV as well as thelongitudinal momentum distribution data at Elab =910A MeV and 88A Me V have been analyzed in a
Glauber-model approach to investigate the possible
ground-state configuration of the 19C nucleus. A com-

*1

*2

parative analysis of both of these experimental data
fails to yield a consistent conclusion regarding a possible ground-state configuration within the leT error barof the experimental data. It is suggested that a considerable change of the core of 19C from a bare 18C
nucleus may take place.

Condensed from the article in Nucl. Phys. A 677, 171 (2000)
Van de Graaff Accelerator Laboratory, Faculty of Science,
Osaka University
Research Center for Nuclear Physics, Osaka University

11

RIKEN Accel. Prog. Rep. 34 (2001)

Enhancement of Low-Energy Dipole Strength inLight Drip-Line Nuclei
H. Sagawa,*1 T. Suzuki,*2 H. Iwasaki,*3 and M. Ishihara[Electric dipole strength, Loosely-bound nucleon, Drip-line nuclei]
We have studied the electric-dipole transition
strength in three nuclei with loosely bound nucleonse~Be8, I!BelO and 1~05) by large-scale shell-model
calculations including the configuration space up to
3nw excitations. We found large low-energy El peaks
below 3 MeV in both I~Be8 and 1~05' The calculated
results in I~Be8, Ex = 2.36 MeV and B(El) = 0.063 e 2
fm2, show good agreement with the recently observed
1- state at Ex = 2.68(3) MeV with B(El) = 0.051(13)e 2fm 2 by Coulomb excitation. 1) In I!BelO, the lowest 1- state is predicted to be around 7 MeV, which
is much higher than the energy in I~Be8. A large
low-energy El strength is predicted in 13 0 at Ex =2.92 MeV with B(El) = 0.056 e2fm 2. The low-energy
E1 strength in I~Be8 and I~05 can be interpreted asa sign of melting of the energy gaps at N = 8 and
Z = 8 near to the drip lines. We pointed out two key
issues to obtain the extremely enhanced El strength

*1
*2

*3

12

Center for Mathematical Sciences, University of Aizu
Department of Physics, Nihon University
Department of Physics, University of Tokyo

at low energy.2) The first one is the effect of extended
wave functions, which enlarges the single-particle transition matrix elements, and also induces decoupling of
the enhanced low-energy E1 strength from the CDR
strength. The second one is coherence in the transition amplitudes between the loosely bound nucleons ,and also between the core and the loosely bound nucleons. In addition, the hole-vibration coupling pictureis used to interpret the splittings of both the energies
and the strength in 1~05. Further experimental andtheoretical efforts are definitely needed to study a newcoherent effect on the El transitions as well as thechange in the shell structure near to the drip lines.
References
1) H. Iwasaki et al.: Phys. Lett. B 491 , 8 (2000).
2) T. Suzuki, H. Sagawa, and P. F. Bortignon: Nucl. Phys.

A 662, 282 (2000).

RIKEN Accel. Prog. Rep. 34 (2001)

Pygmy and Giant Dipole Resonances in Neutron-Rich Nuclei
within the Quasiparticle Representationof the Phonon Damping Model
N. Dinh Dang, V. Kim Au,*1 T. 8uzuki,*2 and A. Arima[Giant dipole resonance, Neutron-rich nuclei, Pygmy resonance, Photonuclear reactions]
Recent years have seen intensive studies of effects
due to varying the ratio of the proton (Z) and neutron(N) numbers on different nuclear-structure characteristics as nuclei deviate from their valley of ,6-stability.
One of the phenomena is the pygmy dipole resonance(PDR) in neutron-rich nuclei or soft dipole mode inneutron halo nuclei. The PDR leads to an enhancement of the dipole strength below the region of theusual giant dipole resonance (GDR). The PDR, byitself, is not a new subject, because it was observed
experimentally in photonuclear reactions in 180 morethan two decades ago. The renewed interest in thisphenomenon arises mainly due to the prospects of using radioactive-isotope (RI) beams to study unstable
nuclei. With the recent method of utilizing the electromagnetic (EM) excitation process at high energies,
the El strength distribution can be studied up to theregion of GDR in light neutron-rich isotopes. 1)
One of the challenges in the theoretical study of exotic nuclei is how to go from the valley of ,6-stability,
where predictions given by various models for major
fundamental nuclear properties are similar, to the region of nuclei with extreme N I Z ratios, where theoretical predictions become quite model-dependent.
The PDR was predicted by several theoretical models starting from an application of the cluster model(CM), where the low-lying dipole mode is described
as a result of oscillation of neutron excess against thecore, the 8kyrme-Hartree-Fock model, the HartreeFock plus random-phase approximation model, to thelarge-scale shell-model (LSSM). The LSSM uses an interaction, which is determined as a least-square fit of
the particle-hole (ph) two-body matrix elements to thebinding and excitation energies of nuclei with mass
number A = 10- 20. The width of GDR was not explicitly calculated in these theoretical studies. Instead, it
was introduced as a width parameter from the Gaussian or Breit-Wigner distribution. The recent preliminary experimental results at GSl 1) have shown thatthe energy-weighted sum (EWS) of the PDR strength

does not follow the prediction of CM. The prediction given by L8SM agrees qualitatively with the preliminary data for the EM cross sections of PDR in
20,220,1) but the GDR shapes given by LSSM disagreewith the well-established experimental systematic forphotonuclear reactions cross sections in 16, 18 0. Given
the rather scarce experimental data on GDR and PDR
in neutron-rich nuclei at present , it is desirable to havean extension toward the region with N » Z based on atheoretical model, which properly includes the damping mechanism and satisfactorily describes the wellknown systematic of GDR shapes in ,6-stable nuclei.
In the present paper the quasiparticle representationof the phonon damping model (PDM)2) is developed
to include the superfluid pairing correlations microscopically. The formalism is applied to calculate thephotoabsorption and the EM differential cross sectionsof El excitations in neutron-rich oxygen and calcium
isotopes. The calculated photoabsorption cross sections agree reasonably well with the available data for
16, 18 0 and 40, 48 Ca. The fractions of EWS of strength
in the region of PD R (E-y :S 15- 16 MeV) and the PD R
peaks in the EM cross sections for 20,220 are also foundin reasonable agreement with experimental systematic.
The deviation from the prediction given by the CM
sum rule shows the importance of the effect of coupling to noncollective degrees of freedom in the damping of pygmy and giant dipole resonances. It is also
shown in this work that, using low-energy RI beams ataround 50-60 MeV In, one can observe clean and evenenhanced PDR peaks without any admixture with the
GDR in the EM differential cross sections of neutronrich nuclei.
References
1) T. Aumann et al.: GSI Sci. Rep . 1999, 27 (2000).

2) N. Dinh Dang and A. Arima: Phys. Rev. Lett. 80,
4145 (1998); Nucl. Phys. A 636, 427 (1998); N. Dinh
Dang, K. Tanabe, and A. Arima: Phys. Rev. C 58,3374(1998); Nucl. Phys. A 645 , 536 (1999).

*1 Institute of Theoretical Physics, Vietnam. Address afterJanuary 1, 2001: Texas A&M University, USA*2 Department of Physics, College of Humanities and Sciences,
Nihon University

13

RIKEN Accel. Prog. Rep. 34 (2001)

Structure of 31Na Studied by the Monte-Carlo Shell Model
Y. Utsuno,*1 T. Otsuka,*2 T. Mizusaki,*3 and M. Honma*4[NUCLEAR STRUCTURE, Shell model, Unstable nuclei]
Since anomalous properties of 31 Na concerning
the mass 1) and the ground-state spin and magnetic
moment 2) were observed in the 1970's, the structureof neutron-rich nuclei around N = 20 has attracted
much interest, particularly concerning vanishing of theN = 20 magic number. Based on the Monte-Carloshell model (MCSM),3) we performed a systematic
shell-model calculation for even-even N rv 20 exotic
nuclei with full mixing between the normal, intruder,and higher intruder configurations for the first time,4)
and gave a comprehensive picture of the region. As for
odd-A nuclei, since we should adopt the J-compressedbases,3) which require much computational time in the
MCSM calculation, such a calculation was unfeasible
until the Alphleet computer system 5 ) was introduced
at RIKEN. In this report, the structure of a neutronrich odd-A nucleus 31 Na, which is expected to be in
the "island of inversion," 6) is studied by the MCSM
with the Alphleet computer system.
The energy levels of 31 Na are shown in Fig. 1. The
ground-state spin 3/2+ agrees with an experiment, incontrast to the sd-shell model prediction of 5/2+. The
calculated magnetic moment of the ground state is
2.17 J-lN with free-nucleon 9 factors being consistent
with the experimental value of 2.283 (38) f..LN. 2 ) The
present study shows that, while the ground state isdominated by the 2-particle 2-hole (2p2h) excitations
from the N = 20 core, 4p4h and higher excited configurations are mixed and lower the ground-state energy by more than 700 ke V. This energy gain gives
rise to a better two-neutron separation energy. The
first excited state obtained by the MCSM calculation
is a 5/2+ state located at 310 keV, in good agreement

512'

3-

31

Na

;;- 2
6

9/2+-

~

~"<

912-j:: __312- -112 _1/2+- -7/2-

It512+-

Ot-

-

7/2+-

3/2+-

Exp.

5/2+3/2+--

MCSM

Fig. 1. Experimental energy levels of 31Na (Exp.) compared with those of the MCSM calculation (MCSM).
*1

*2
*3
*4

14

Japan Atomic Energy Research InstituteDepartment of Physics, University of Tokyo
Department of Law, Senshu University
Center for Mathematical Sciences, University of Aizu

with a recent measurement of 350 ± 20 ke V. 7) On theother hand, this level was calculated to lie around200 keVin the OpOh + 2p2h truncation. A comparison between the truncated and full calculations clearly
indicates the importance of the higher intruder configurations (i. e., 4p4h and higher excited configurations from N = 20 core): these configurations lower
the ground state more than the first excited state, giving rise to a better agreement with experiment. The
higher intruder configurations occupy the ground state
by about 10%. The B (E2; 3/2+ ~ 5/2+) = 200 e 2fm 4
is obtained with the effective charges ep = 1.3 e anden = 0.5 e, suggesting a strong deformation similarly
to the adjacent even-A nucleus, 32Mg. This B(E2)value corresponds to /32 = 0.53 by assuming an axiallysymmetric rotor with K = 3/2.
The negative-parity states are also of interest, partly
because the competition and mixing between the Iplh
and 3p3h configurations can be compared with those of
the OpOh and 2p2h configurations in the positive-parity
states. The present calculation indicates that the yrast
negative-parity states shown in Fig. 1 are dominatedby 3p3h configurations. The truncated shell-model calculation with the same interaction shows that states
dominated by Iplh are expected to lie higher than the
yrast negative-parity states by more than 1 MeV. This
picture is in sharp contrast with the former shell-model
prediction,6) in which the yrast negative-parity states
are composed of Iplh configurations for all nuclei inthis region.
In order to confirm the validity of our calculation
concerning the competition and mixing of various configurations, the role of pf-orbits on the observed quantities is examined in more detail. In the MCSM calculation, the 31 state of a neutron-rich nucleus, 28Mg,
lies at 5.28 MeV, very close to the experimental position of 5.17 MeV. The two-neutron separation energies
of N = 20 nuclei, which are also very sensitive to theeffective single-particle energy4 ) of the pf shell, are inexcellent agreement with an experiment for N = 20
isotones ranging from Z = 10 to 14.
References
1) C. Thibault et al.: Phys. Rev. C 12, 644 (1975).
2) G. Huber et al.: Phys. Rev. C 18, 2342 (1978).
3) T. Otsuka et al.: Phys. Rev. Lett. 81, 1588 (1998) andreferences therein.
4) Y. Utsuno et al.: Phys. Rev. C 60, 054315 (1999).
5) T. Otsuka et al.: Prog. Theor. Phys. Suppl. No.138, 24(2000) .
6) E. K . Warburton et al.: Phys. Rev. C 41, 1147 (1990).
7) B. V. Prityckenko et al.: submitted to Phys. Rev. Lett.

RIKEN Accel. Prog. Rep. 34 (2001)

A Search for a Unified Effective Interaction for Monte-Carlo
Shell-Model Calculations (II)M. Honma,*l B. A. Brown,*2 T. Mizusaki,*3 and T. Otsuka*4[Shell model, Effective interaction]
The Monte Carlo Shell Model (MCSM)l) has extended the feasibility of the nuclear shell model far
beyond the current limit of the conventional diagonalization technique. We can now study various nuclear
properties in the whole pf-shell, or even in heavier mass
regions from microscopic viewpoints. At this stage,
it is a quite challenging problem to construct a unified shell-model effective interaction which is successful
over a wide model space, including both the beginningand the middle of the shell.
We can approach to this problem by a "modelindependent" method, in which two-body matrix elements and single-particle energies are treated as parameters, and are determined by a least-squares fit to
the experimental binding energies and the excitationenergies. This technique was successfully applied tothe sd-shell, and led to success concerning the USD
interaction. 2)
For pf-shell calculations, we have attempted several
series of iterative fitting calculations. 3) The shell-model
calculations were carried out by a massive parallel computer, Alphleet, at RIKEN. In this report we introduce
one promising interaction, called the GF40A 4) interaction, as described below.
Starting from a realistic G-matrix interaction 5)
based on the Bonn-C potential, 195 two-body matrix elements and 4 single particle energies were determined by fitting to 635 binding and excitation energy
data. We adopted the data of the following 91 nucleids:
47- 51 Ca, 47- 51 SC, 47- 52Ti, 47-55 V, 48- 56 Cr, 50- 58 Mn,
52-6o Fe, 54-61 Co, 56- 68Ni, 58- 69 Cu, 60- 69 Zn , 64Ga and64Ge. Nuclei of A < 47 are excluded in the fit so as toreduce the effect of the sd-shell configurations. In order
to separate well-determined parameters from the rest,
we varied 40 linear combinations of the parameters on
the basis of the Linear Combination method. 6) We canapproximate the MCSM energies by taking only a few
dominant (optimized) bases in the form of deformed
Slater determinants (few-dimensional approximation;
FDA 4)). The FDA can be improved further by adding
suitable empirical corrections. The 2-body matrix elements were scaled according to a mass-dependent factor (A/42)-O.3 relative to the values at A = 42. As
a result of the fitting calculations, the GF40A interaction was obtained with an estimated rms error of
*1
*2
*3
*4

Center for Mathematical Sciences, University of Aizu
Michigan State University, USA
Department of Law, Senshu University
Department of Physics, University of Tokyo...... --(10+)
10+ 1 - - ' ••8+3 - -

8s-a>===...

8+ - -~:~..... - - ( 8 + )

6

6
x

W

4
2+ 1 - _···········- - 2 +2o0+ 1 - _··········- - 0 +

GF40A

EXP.

Fig. 1. Energy levels of 56Ni. Experimental data are takenfrom Ref. 7.

255keV.
The GF40A interaction was examined from various
viewpoints and was found to be quite successful in describing the systematics of binding energies, effective
single-particle energies, semi-magic structure of N or
Z = 28 nuclei, and the isospin structure of the lowest
states in N = Z odd-odd nuclei.
As an example, the energy levels of 56Ni are shown in
Fig. 1. Levels which are used for the fit are connectedby dotted lines. Theoretical values are obtained by
the FDA with empirical corrections, except for the 0+
states, which are obtained by the MCSM with 30 basis
states. The agreement between the theory and theexperiment is satisfactory.
We are now investigating to what extent we can determine the parameters without uncertainty.
References
1) T. Otsuka et al.: Phys. Rev. Lett. 81 , 1588 (1998).
2) B. A. Brown et al.: Ann. Rev. Nucl. Part. Sci. 38, 29(1988).
3) M. Honma et al.: RIKEN Accel. Prog. Rep. 33, 16(2000).
4) M. Honma et al.: to be published in Nucl. Phys. A.
5) M. Hjorth-Jensen et al.: Phys. Rep . 261, 125 (1995).
6) W. Chung: Ph. D. thesis, Michigan State University,
1976.
7) R. B. Firestone et al.: Table of Isotopes, (Wiley, New
York, 1996).

15

RIKEN Accel. Prog. Rep. 34 (2001)

Monte-Carlo Shell Model Calculation for Medium-Heavy Nuclei
N. Shimizu,* T. Otsuka,* T. Mizusaki, and M. Honma[Shell model, Nuclear structure, Collective motion, Computational physics]
One of the interesting topics in nuclear physics is aninvestigation of nuclei which have a triaxial deformed
structure. These properties are seen in the Xe-Ba,
Pt-Os regions. In 1978, an innovative study was cond ucted utilizing the 0 (6 ) limit of the Interacting Boson
Model,l) and many efforts have continued until now tounderstand these features more precisely. In this report, we discuss this topic microscopically by utilizing
the nuclear shell-model description.
We focus on 132Xe, which is considered to have triaxial deformed features. The excitation energies of 132Xe
are shown on the right-hand side of Fig. 1, where wecan see such characteristics. For example, the excitation energy of thestate is lower than that of thestate.
In our nuclear shell-model calculation, the singleparticle states of the model space are taken as one major shell (N, Z = 50- 82), which is sufficiently large todescribe the nuclear collective motion. Because the dimension of the Hilbert space becomes too large (larger
than 10 7 ) to diagonalize the shell-model Hamiltonian
in a conventional way, we introduce a new version of
the Monte-Carlo shell model (MCSM) method using
a condensed pair 2) in order to overcome such difficulties. In the former MCSM method which was recently
developed by M. Honma et al.,3) the obtained state ispresented as a linear combination of a small number(rv 30) of Slater determinant bases which are selectedstochastically. In order to include the contribution ofa pairing correlation more efficiently, we replace theSlater determinant by a condensed pair, which is a kindof generalized Cooper pair. The condensed pair basis is
written as (Lij AijcIc})NI-)4), where cJ, 1-), and Aijdenote the creation operator of a spherical harmonic
oscillator, an inert core, and arbitrary amplitudes ofthe pair, respectively.
The left-hand side of Fig. 1 denotes the theoretical

2t

University of Tokyo

16

4t

3.0
--8+

5+
=6+

--6+

__ 4+

2.0

5>
6
Q.)

--6+

--3+
--4+
--2+

X

---i6
--5
--4

-3
--4+
--2

W

1.0

0.0

--2+

--2+

--0+

--0+

MCSM

expo

Fig. 1. Energy levels of 132Xe.

result obtained by the MCSM. This result well reproduces the experimental values, which are drawn on theright-hand side. It shows the characteristics of triaxial deformation discussed before, and we can say that
the MCSM result describes the nuclear collective motion sufficiently, including the degree of freedom of atriaxial deformation.
These computations were carried out mainly using
the Alphleet computer system at RIKEN.
References
1) A. Arima and F. Iachello: Phys. Rev. Lett. 40 385(1978).
2) N. Shimizu , T. Otsuka, T. Mizusaki, and M. Honma:
Phys. Rev. Lett. 86, 1171 (2001).
3) Y. Utsuno, T. Otsuka, T. Mizusaki, and M. Honma:
Phys. Rev. C 60, 054315 (1999) and references therein.
4) T. Otsuka and N. Yoshinaga: Phys. Lett. B 168, 1(1986).

RIKEN Accel. Prog. Rep. 34 (2001)

Normal and Super Deformation in 56Nit
T. Mizusaki, T. Otsuka, M. Honma, and B. A. Brown*[Shell model, Shape coexistence]
Investigating the structure of the doubly-magic 56Ni
nucleus has become a particularly interesting subject .
The spherical ground and low-lying states are a touchstone for the validity of the N = Z = 28 doubly closedshell structure.1 ) In addition, salient deformed bands
have recently been observed 2) in 56Ni. These collective
bands with a large deformation coexist along with thespherical yrast band. For describing this shape coexistence in a single framework, the shell model is quite
suitable and the Monte-Carlo shell model (MCSM)3,4)
is one of the powerful tools used to achieve large-scale
shell-model calculations. In Refs. 4 and 5, we investigated the yrast band and one of the deformed bandsof 56Ni. The level scheme of these bands has been
demonstrated to be properly described in full pf-shell
calculations with the FPD6 interaction. 6) In this paper, with an enlarged shell-model space, we present
a more comprehensive description of the structure of
the rotational bands of 56Ni and its neighbor N = Z
nuclei.
In Fig. 1, we show a theoretical and experimental 2)
level scheme for yrast and two deformed bands. Because there is no candidate for a second deformed bandwithin the pf-shell, the shell-model space should be extended. And because the 99/2 orbit has an opposite
parity to that of the pf-shell orbits, its effect on lowspin yrast states is expected to be small. However,
one-nucleon excitation from pf-shell orbits to the 99/2
orbit can take place. In order to investigate this picture, the full pf plus 99/2 shell model space is taken into
account. For this space, the FPD6 interaction should
also be extended, which is discussed in Ref. 7. Suchan extended calculation nicely describes these two deformed bands of 56Ni, as shown in Fig. l.
With the analysis of the MCSM wavefunctions, thefirst deformed band of 56Ni is a positive parity one
and its nature is, on average, 4p4h excitation on topof the ground state within the pf-shell. On the other
hand, the second deformed band is a negative parity one where, on average, one nucleon is promoted
into the 99/2 orbit from the first deformed configuration. With the same interaction, the deformed band of
58Cu8) can also be well described. In this band, the occupation number of the 99/2 orbit is almost two. This
picture is quite similar to the Skyrme HF results .with
the SLy4 interaction. 2,8) In the present calculation, thetwinning2) between the second deformed band of 56Ni
Condensed from the articles in Phys . Scr. T 88, 107 (2000) 7)
and in Nucl. Phys. A (in press)9)
Superconducting Cyclotron Laboratory and Department of
Physics and Astronomy, Michigan State University, USA

Exp.

MCSM
-17
- 1 8+

20-16+__1 3- 1 2+

;;:-

-10+

(!)

6 10
X

~

16-

_

14-

-

12-

-

_I I-

=
-

97-

-(15 )-10- 8=6- 4--(14+)-(13)_(12+)

-

(12+)

5-

-

(I I )_(10+) _

(9)

-10+
_

8+ -

- 6+ - 4+ =

8+
6+

-

10+ -

(8+)

8+ _

(6+)

_

(4+)

6+ -

2+

4+
2+
0+

(17)

-15-

-14+
14+

-12+

-

=

4+

_2T

0

_0+

Fig. 1. Experimental levels 2 ) of 56Ni compared with the
MCSM result with an extended FPD6 Hamiltonian.

and the band of 58CU is still in question. A further
quantitative investigation is needed. A systematic description of large or super deformed bands in the A rv
60 region within the pfg9/ 2 shell-model space is quite
interesting.
This work was supported in part by a Grant-inAid for Scientific Research (A) (2) (10304019) from
the Ministry of Education, Science and Culture. Numerical calculations were carried out partly by a massively parallel computer, Alphleet, at RIKEN. BAB
was supported by NSF grants PHY-9605207 and PHY0070911.
References
1) G. Kraus et al.: Phys. Rev. Lett. 73 , 1773 (1994).
2) D. Rudolf et al.: Phys. Rev. Lett. 82, 3763 (1999).
3) M. Honma, T. Mizusaki, and T. Otsuka: Phys. Rev.
Lett. 75 , 1284 (1995); Phys. Rev. C 53, 2786 (1996);
Phys. Rev. Lett. 77, 3315 (1996).
4) T. Otsuka, M . Honma, and T. Mizusaki: Phys. Rev .
Lett. 81 , 1588 (1998) .
5) T. Mizusaki, T. Otsuka, Y. Utsuno, M. Honma, and T.
Sebe: Phys. Rev. C 59, R1486 (1999).
6) W. A. Richter, M. G. van der Merwe, R. E. Julies, and
B. A. Brown: Nucl. Phys. A 523 , 325 (1991).
7) T. Mizusaki, T. Otsuka, M. Honma, and B. A. Brown:
Phys. Scr. T 88, 107 (2000).
8) D. Rudolf et al.: Phys. Rev. Lett. 80 , 3018 (1998).
9) T. Mizusaki, et al.: Nucl. Phys. A, in press.

17

RIKEN Accel. Prog. Rep. 34 (2001)

Effects of the Neutron Spin-Orbit Density on the Nuclear
Charge Density in Relativistic Models
H. Kurasawa* and T . Suzuki[NUCLEAR MODEL, Charge density, Neutron spin-orbit density, Relativistic model]
In recent years, it has been shown that many of thenuclear ground-state properties are well reproduced by
Hartree-Fock calculations using the Skyrme effective
forces (SHF)l) and by relativistic mean-field calculations (RMF).2) For a long time, however, there hasremained a problem that SHF and RMF cannot explain the difference between the cross sections for elastic electron scattering from 40Ca and 48Ca. Since they
are described as closed-shell nuclei, it was expectedthat the difference could be easily understood by SHF
and RMF; but the problem has not yet been solved.
In 1972, Bertozzi et al. 3 ) took into account the effects of the neutron spin-orbit charge density as a relativistic correction to SHF. The relativistic correction
was derived by expanding the Pauli current of the freenucleon in terms of 1/M, M being the mass of thefree nucleon . They found that although the relativistic correction was not negligible, it was not enough to
explain the difference between the two cross sections.
In 1976, Miller 4) analyzed the same data using RMF ,but again could not reproduce the experimental data.
The Pauli current made the agreement rather worse
between his results and the experiment. Since then,there have been no efforts to solve this problem, as far
as the authors know. 5 )Recently, new parameter sets of the Skyrme forces
and the relativistic models have been proposed for abetter description of the nuclear ground-state properties. By using those sets, we have shown that although
RMF with the new parameter sets can well reproduce the experimental data, SHF still fails to explainthem. 6 ) Moreover, we have clarified the relationshipbetween the relativistic and non-relativistic models. In
the relativistic models, the effective mass coming fromthe Lorentz scalar potential yields an additional spinorbit charge density as a relativistic correction. This
correction improves the agreement between the experimental data and the RMF results.
We calculate the cross section for elastic electron
scattering using phase-shift analyses. For this purpose
we must obtain the nuclear charge density, which is
given bypc(r) =

Jd3q(27r)3 exp( -iq· r)(OI,8(q)IO) ,where q denotes the momentum transfer from the electron to the nucleus. In relativistic theory, the groundstate expectation value of the time component of theDe partment of Physics, Chiba University

18

nuclear current is given by(OI,8(q)IO) =J

d 3 x d3 yexp(iq · (x + y))x

L (CET(Y)PT(X) + F2T(y)WT( X)) ,T

where the sum of 7 is performed with respect to theproton and the neutron, 7 = p , n. The functions
G ET(Y) and F2T (y) are obtained by inverse Fouriertransformations of the Sachs and Pauli form factors,
respectively. The nucleon density, PT(X) , and the spinorbit density, WT(x), are given by" 2ja+ 1 (22)
PT (r ) -_ '~4 2
C ol + Fa ,7rr
a

W (r) =T

+ 1 d (M - M*(r) G
M ~ 47rr2 dr
MaFa

f.1T '"""' 2jaa"'a + 1 C a2 _ "'a2Mr- 1 F2)
a
.

+ 2Mr

(1)

In the above equations, C ol and Fa denote the large
and small components of the single-particle wave function, respectively,= (- 1)j - e+l /2(j+l/2) the eigenvalue of - (1 +0" . f.) , and M*(r) the nucleon effective
mass given by M*(r) = M - Us(r) , where Us(r) is theLorentz scalar potential due to the (J"-meson.
The relationship between the relativistic and nonrelativistic models is very clear. In non-relativistic
models , the neutron charge and spin-orbit charge densities are usually neglected in estimating the electron
scattering cross section. Bertozzi et al. 3 ) took into account the neutron charge density and a part of thespin-orbit charge density in a non-relativistic framework. Their spin-orbit density was obtained from
Eq. (1) by setting M* (r) = M and neglecting the F~ ­term.
We have shown that the spin-orbit density due to theeffective mass in Eq. (1) is very important in a relativistic model for reproducing the experimental data. 6 )"'aReferences

1) D. Vautherin and D. M. Brink: Phys. Rev . C 5 , 626(1972).
2) B. D. Serot and J. D . Walecka: Adv. Nucl. Phys. 16, 1(1986).
3) W. Bertozzi, J. Friar, J. Heisenberg, and J. W. Negele:
Phys. Lett. B 41, 408 (1972).
4) L. D. Miller: Phys . Rev. C 14, 706 (1976) .
5) H. Feshbach: Theoretical Nuclear Physics: Nuclear Reactions (John Wiley & Sons, New York, 1992) .
6) H. Kurasawa and T. Suzuki: Phys. Rev . C 62 , 054303(2000) .

RIKEN Accel. Prog. Rep. 34 (2001)

Analysis of the Matter Distribution of Nuclei
with a Gaussian-Basis Expansion
A. Kohama, S. Yamaji, R. Seki,* and A. Arima
NUCLEAR REACTION: Matter distribution of nuclei, X2-Fitting, Proton-nucleus elastiC][scattering
The one-body matter-density distribution, p( r), isa fundamental and important quantity for nuclear
physics. A consistent study of this quantity for unstable as well as stable nuclei will result in a deeper
understanding of nuclear-structure physics.
To this end, we have investigated a method to determine the density distribution of nuclei based on experimental data by a X2-fitting.l) We have demonstrated
how it is affected by the quality of data. This was done
to prepare for upcoming experiments at the RI-Beam
Factory of RIKEN.
For the above demonstration of X2-fitting we usedpseudo-data which were created from random numbers
distributed around the theoretical cross section of the
proton-nucleus elastic scattering at various momentum
transfers. We took the case of p_ 58 Ni scattering as an
example, and generated 25 sets of pseudo-data forming a data-set group. A different data-set group corresponded to a different intensity of the nuclear beam. 2)
The density-distribution, p(r), was expanded in termsof a Gaussian series 3 ) in order to avoid any assumption
concerning the functional form of the density. The expansion coefficients were determined by minimizing X2
between the theoretical cross sections and the pseudodata;

Here, N is the number of data-points , and Eo is theerror of each data-point. The superscript "data" ofthe cross section implies pseudo-data, and "theory"
implies the theoretically obtained value. We used theexpression of the first-order optical potential in the
Glauber approximation for the theoretical cross section, which includes the density-distribution explicitly.
We have found that the density distributions obtained with the Gaussian-basis functions show simi-

2.0

5"Ni

1.5

I

!
...
Cl
<{

1.0

0.5

0.0

rms [fm]: 3.747 ± 0 .022
-0.5

0

2

4

6

r [fm]

Fig. 1. Example of the results after a X2-fitting. The curves
show the matter-density distributions, r2 x p(r), obtained from 25 pseudo-data sets of the cross section.
One curve corresponds to one pseudo-data set. The
Gaussian-series expansion here contains 20 terms.

lar behavior at the surface, even if the quality of thedata becomes worse, i. e., the surface is determined
well (Fig. 1). The statistical errors were found to
be concentrated in the central region of p(r), which
is a similar situation to the charge-distribution. To
apply the Gaussian-basis function for determining thedensity-distribution by a X2-fitting is a good way to see
whether unstable nuclei have an extended structure. 4 )References
1) J. L. Friar and J. W. Negele: Adv. Nucl. Phys. 8, 219(1975).
2) A. Kohama, S. Yamaji, R. Seki, and A. Arima: in preparation.
3) E. Hiyama and M. Kamimura: Nucl. Phys. A 588 , 35c(1995).
4) I. Tanihata et al.: Phys. Lett. B 160, 380 (1985).

Department of Physics and Astronomy, California State
University, Northridge, and W. K. Kellogg Radiation Laboratory, California Institute of Technology, USA

19

RIKEN Accel. Prog. Rep. 34 (2001)

Microscopic Foundation of
the Fermion Dynamical Symmetry Model:0(6) Limit
Y. M. Zhao,* l S. Yamaji, N. Yoshinaga,*2 and A. Arima[SD pair approximation, Fermion dynamical symmetry model]
The concept of dynamical symmetry has been widely
applied in nuclear structure theory. The most successful approach is the interacting sd boson approximationof the shell model (IBM).!) Similar to the IBM, thefermion dynamical symmetry model (FDSM)2) uses
SP(6) or SO(8) SD nucleon pairs to construct the subspace. However , the nucleon pairs in the FDSM are
assumed to be symmetry dictated. The Hamiltonianin the FDSM is very different from the commonly usedone.
Recently, we checked 3) using the SD pair approximation of the shell model (the NPA)4) the assumptions made in the FDSM for a realistic 132Ba nucleus
which displays 0(6) behavior in both the IBM andthe FDSM. It was confirmed that those assumptions
are reasonable for this nucleus. Based on this work,
we have proposed a correspondence between a S Dpair subspace and the FDSM subspace. By apply-

*1
*2

20

Department of Physics, Southeast University, China
Department of Physics, Saitama University

ing a pairing plus quadrupole interaction the FDSM
Hamiltonian parameters of nucleus 13 2Ba nucleus are
obtained via this correspondence. The parameters obtained in this way are consistent with those taken phenomenologically in the previous studies. 4) The FDSM
calculation is performed using the calculated parameters. The calculated results agree with the experimental data very well.
References
1) A. Arima et al.: Ann. Phys. (N.Y.) 99, 253 (1976); Ann.
Phys. (N.Y.) 111 , 209 (1978); Ann. Phys. (N.Y.) 123,468 (1979).
2) C. L. Wu et al.: Phys. Rev. C 36, 1157 (2000).
3) J. Q. Chen: Nucl. Phys. A 626,686 (1997); Y. M. Zhao
et al.: Phys. Rev. C 62, 014304 (2000).
4) Y. M. Zhao et al.: Phys. Rev. C 62, 024322 (2000); Y.
M. Zhao, S. Yamaji, N. Yoshinaga, and A. Arima: tobe published.

RIKEN Accel. Prog. Rep. 34 (2001)

TDHF Calculation of the Excitation of Isoscalar Giant Resonances
K.-H. Kim, S. Shlomo,*l and T. Otsuka*2[Giant resonances, Random-phase approximation, Time-dependent Hartree-Fock]
Recently, experiments on the excitation of the giant
resonances have been developed and some experimental data concerning the isoscalar giant monopole resonances (ISGMR) and isoscalar giant dipole resonances(ISGDR) have been obtained for several nuclei, suchas 90Z r 116S n 144Sm and 208Pb by means of inelastic
a scatt~ring.l),,
The situation concerning the ISGMR and ISGDR
has changed. The location of the experimental dataof the excitation energies of the ISGDR is found tobe higher than results obtained from the Hartree-Fock(HF) random-phase-approximation (RPA) approach. 2)
Since the energies of the ISGMR and ISGDR are directly connected to nuclear matter incompressibility,3)
it would be interesting not only to study the microscopic structure of giant resonances, itself, but also to
determine the nulear matter incompressibility, which
is important in relation to the equation of state.
It is considered that such a difference between theexperimental data and the calculation is mainly due tothe absence of full self-consistency between the mean
field and particle-hole interaction in the RPA. 2) In
this study, we applied the time-dependent HartreeFock (TDHF) method 4) to a calculation of the exci-*1*2

tation of the ISGMR and ISGDR. In this method ,the self-consistency is fully satisfied, and the Coulomb
and spin-orbit terms, which are neglected in the RPA
calculation, are included. Such a fully self-consistentcalculation has not been done in RPA calculations sofar.
Numerical calculations are now in progress. We calculate the strength function (S(E)) using the transition density obtained from the TDHF calculation andcompare it with the result of the usual RPA calculationand the experimental data. We would like to know if
only a partially self-consistent calculation is sufficientor whether full self-consistency is necessary, and also
if effects of the Coulomb and spin-orbit terms show up
in the calculation.
References
1) H. L. Clark et al.: Nucl. Phys. A 649, 57c (1999).
2) M. 1. Gorelik, S. Shlomo, and M. H. Drin: Phys. Rev.
C 62, 044301 (2000).
3) S. Shlomo and D. H. Youngblood: Nucl. Phys. A 569,
303 (1994).
4) K.-H. Kim, T. Otsuka, and P. Bonche: J. Phys. G 23,
1267 (1997).

Cyclotron Institute, Texas A&M University, USA
Department of Physics, University of Tokyo

21

RIKEN Accel. Prog. Rep. 34 (2001)

Theoretical Search for Shears Bands In the A""gO Mass Region
H. Madokoro, J. Meng,*l M. Matsuzaki,*2 and S. Yamaji[NUCLEAR STRUCTURE 84RbJ
In previous work,l) we examined the so-called shears
band in 84Rb, for which experimental data wereobtained. 2) Our result concerning the relativistic mean
field (RMF) model shows that this model can nicely
reproduce the observed trends of the shears band in
84Rb. In spite of the fact that many high-K bands
have been observed in this mass region, very few ofthem have been assigned as shears bands up to now.
It is an interesting topic to clarify, from a theoreticalpoint of view, whether or not there exist other shears
bands which have not been observed in this region.
As the first work in this direction, we notice theN = 47 isotones, which have the same configuration
as the observed shears band in 84Rb, and therefore areconsidered to be good candidates for new shears bands.
Here, we examine 82Br and 83Kr.
We use the RMF model, which is a fully microscopic
one with more sophisticated interaction than the simple pairing + QQ force. The RMF model can be generalized to a uniformly rotating frame with a constantrotational frequency, n = (n 1 , n2, n3).3,4) The resulting coupled equations of motion are solved by expanding both the nucleon and meson fields in terms of thethree-dimensional harmonic oscillator eigenfunctions.
A parameter set named NL3 is used in all of our calculations. For 82Br and 83Kr, the proton and neutron
configurations in the high-j (19 9 / 2 ) orbital are assumed
to be the same as those of 84 Rb. Only those in the lowj (pf) orbitals for protons are different.
The calculated tilt angles (8) for 82Br and 83Kr,
which are measured from the 3-axis in a body-fixed
frame are shown in Fig. 1. Also displayed is the resultof 84Rb, which is taken from Ref. 1. For 84Rb, it stays
at 8 rv 55-65° and is comparable with the predicted
property of the shears bands, while in the case of 82Br
and 83Kr, the tilt angles are larger and move toward
8 rv 90° along with an increase in the rotational frequency. This trend is similar to that seen in normal
high- K bands in well-deformed nuclei, rather than theshears bands.
Figure 2 shows the B(M1)j B(E2) ratio. We cansee that for 84 Rb the expected tendency of a smooth
decrease is well reproduced. For 82Br and 83Kr, on
the other hand, the calculated B(M1) j B(E2) values do
not show such a decrease. From these results , we canconsider that these two bands calculated for 82Br and
83Kr will not be shears bands. The difference between
84Rb and other isotones can be attributed to the net
*1

*2

22

Department of Technical Physics , Peking University, China
Department of Physics , Fukuoka University of Education

contribution to the total spin from the low-j pf-shells.
Table 1 shows J~), which represents the net contribution from the low- j (p f) proton levels. Clearly,
the main difference between 84 Rb and other isotones
9080
70 _-------------------............~. ~.'~.'~.'~.':.-'~.'::.~.'''.'',".",~.,",~.,::.:::.:.:::.:.~. -:..~.~,:,~,~,

60

:b 50
<1)

~40

82Br(cal)
83Kr(cal)84Rb(cal)

30
20
10

o
0.3

0.4

0.5

0.6

0.7

0.8

Q(MeV)

Fig. 1. Tilt angles as functions of the rotational frequency.

60 ~----,-----~----~~----.-----~
50

.'

.

-

....................... .........

..........

10o ____ ______ ____ ______ ____
~

0.3

~

0.4

~

~

0.5

0.6

~

0.7

_J

0.8

Q(MeV)

Fig. 2. B(Ml)j B(E2) ratio as functions of the rotationalfrequency.

Table 1. Net contribution from the proton pf-Ievels.
J(p)
pf

82Br
83Kr
84Rb

(1.7, 0.0, 0.2)
(1.3 , 0.0 , 0.0)
(1.0, 0.0, 2.5)

is the 3-component of J~). This difference stems fromthe fact that in 8 4 Rb only one of the [303]5/2 levels(k = ±5/2) is occupied, while for other isotones bothof the [303]5/2 levels are empty. We can say that the
spin-polarization in the [303]5/2 levels is important for
the appearance of the shears bands in this case. Systematic studies would be necessary in order to give adefinite conclusion on the condition for the appearanceof the shears bands.

References
1) H. Madokoro, J. Meng, M. Matsuzaki, and S. Yamaji:
Phys. Rev. C 62, R61301 (2000).
2) H. Sehnore et al.: Phys. Rev. Lett. 82 , 4408 (1999).
3) W. Koepf and P. Ring: Nuel. Phys. A 493, 61 (1989);
Nuel. Phys. A 511, 279 (1990).
4) H. Madokoro and M. Matsuzaki: Phys. Rev. C 52 ,R2934 (1997).

23

RIKEN Accel. Prog. Rep. 34 (2001)

Study of Rotational Motion in U nstable Nuclei
T. Nakatsukasa, H. Madokoro, and T. Horibata*[Rotational motion, Unstable nuclei , Cartesian mesh method]
The aim of this work is to study the structure of unstable nuclei near the drip line which are expected to
be produced in the RI-beam factory of RIKEN. The
target mass region of our study is light mass deformed
nuclei in which the mean-field approximation is considered to be well valid. In the region where we focus our attention, there are several topics, such as thenuclear shape at the high-spin region and the stability of a loosely bound system against rotational motion. Especially the shape of nuclear deformation has
great concern with any exotic nuclear rotational motion. Therefore, a detailed study on the density distribution of nucleons near the surface would be indispensable to understand the excitation modes which are
expected to be found in this mass region.
As for the numerical technique, a well-adopted
method to solve the Hartree-Fock-Bogoliubov (HFB)
equations in a self-consistent manner is to expand thewave functions in terms of some basis functions. A typical and frequently used example is the eigenfunction ofa three-dimensional harmonic oscillator. This method,
however, is not suitable for cases in which we do notknow a priori the asymptotic form of the wave functions, for example, the case of unstable nuclei near the
drip line, which mayor may not have halo structures.
On the other hand, for a search of exotic deformations,which is also one of the most interesting topics in the
study of unstable nuclei, the basis-expansion method
is not very good, thus requiring us to optimize the deformation parameters of the basis function.
These shortcomings come from the fact that the as-

Aomori University

24

sumed shape of the basis functions may affect the resulting shape of the wave functions. Therefore, analternative method is desired in our case. For such
purposes, the Cartesian mesh method based on the
Skyrme-type interactions is one of the most promising techniques, and has been frequently employed. 1)
The scope of our work is to develop a computer code
which can handle the higher order correlations of nuclei as well as the pairing correlation by incorporating the three-dimensional cranking approach, therandom-phase approximation, the generator coordinate method as well as the angular-momentum projection technique.
As a first step in our investigation, we have just developed a computer code which can carry out HartreeFock calculations based on the relatively simple density dependent force involved in the Cartesian meshmethod. 2 ) A trial calculation of 16 0 is in progress. In
the future , the code will be extended to perform calculations with more sophisticated interactions, such as
the Skyrme force (Skyrme-Hartree-Fock) or the relativistic meson exchange force (relativistic mean field).
References
1) P. Bonche, H. Flocard, P. H. Heenen, S. J. Krieger, and
M. S. Weiss: Nucl. Phys. A 443, 39 (1985); N. Tajima,
S. Takahara, and N. Onishi: Nucl. Phys. A 603, 23(1996); M. Yamagami and K. Matsuyanagi: Nucl. Phys.
A 672, 123 (2000).
2) H. Flocard, S. E. Koonin , and M. S. Weiss: Phys. Rev.
C 17, 1682 (1978).

RIKEN Accel. Prog. Rep. 34 (2001)

Pseudospin Symmetry and Spin Symmetry
K. Sugawara-Tanabe,* S. Yamaji , and A. Arima[Pseudospin, Spin, Relativistic mean-field, Symmetry, Deformed fieldl
The pseudospin concept in deformed nuclei is as follows. The single-particle levels with jz = 0 = f!z + 1/2,
and j~ = 0 + 1 = f!z + 2 - 1/2 lie very close in energy; these two levels are labeled jz = iz - 1/2 andj~ = iz + 1/2 with iz = f! + 1. In this paper, we
compare the pseudospin pair levels, iz ± 1/2, with thespin pair levels, f!z ± 1/2, in a relativistic mean-field.
The eigenfunction 'Ij;( T) for the Dirac equation with anaxially symmetric deformed potential has two components, i. e., an upper (large) component 9 and a lower(small) component f. Using a cylindrical coordinates(r, tp, z), each 9 and f in 'Ij;(T) has two amplitudes,i.e., g~ k and f~ k' where k denotes the other quantum nu~bers exc'ept for 0, and ± corresponds to thespin wave function with Sz = ±1/2. Both of g~ k andf~ k are functions of rand z. By inserting thi~ definit'i on into the Dirac equation, we obtain an equation
for g~ k which has a similar form to that for f~ k'
Let 'us assume the case where the exact pseudospin
doublet appears, i.e., oVv /8z = 0, which is equivalent to 8Vs /oz = 0, and oVv /or = 0, equivalent to
oVs / or = (see Ref. 1). In the pseudospin pair levels,
k corresponds to [N, n z, f!z]' and k' to [N, n z, f!z + 2],
if we use the asymptotic quantum number. Then, theequation for gO+~+,k (fo+;)+,k and that for g~ ,k (f::),k become the same form, except for the energy eigenvalue,
EO+ 1 ,k' and EO,k' We wish to mention the other amplitudes of the pseudospin pair levels, i. e. f~,k (gZ ,k)and f:31; (g~1~)· Under the same conditions to derive the' exact pseudospin doublet, they follow different
equations. In addition to the difference in E O + 1 ,k ' andEO ,k, the centrifugal term is different. The centrifugal term is proportional to 0 - 1/2 for f~, k (gZ ,k)and 0 + 3/2 for f~1; (g~1~), respectively. Because
the pseudospin is f~r two 'levels with [N, n z, f!zlO( =f!z + 1/2) and [N, n z, f!z + 210 + 1 (= f!z + 3/2), f!z is0- 1/2 for the former level and f!z + 2 = 0 + 3/2 forthe latter level. The amplitudes f~, k and f~~; (gZ ,k°and g~1~) correspond, respectively, to these pair levels, be~ause the centrifugal term corresponds to thez-component of the orbital angular momentum. On
the other hand, f::,k (g~,k) and f~,1; (g~~~) have unnatural f!z = 0 + 1/2. Thus, the amplitudes where thepseudospin symmetry is found have unnatural f z . We
name them unphysical amplitudes, and call the amplitudes with natural f!z physical amplitudes. Of course,
the energy eigenvalue EO,k is the same for all four amplitudes in the level with the same 0 and k, i.e., gZ ,k'g:! ,k' J:;,k and J~, k'We now consider the spin-pair levels, i. e. the levels
with j z = f!z + 1/2 and j~ = fz - 1/2. In this case thespin pair levels are denoted by [N, n z, f!zlO( = f!z -1/2)
and [N, n z, f!zlO + 1 (= f!z + 1/2). Then, k equals to k'corresponding to [N, n z, fzl. The physical amplitudes
O+1 (gO+l), because both
become J:: , k(g~), k and f +,k+,kstates have f!z = 0 + 1/2. On the other hand, f~, k andf~~; (gZ ,k and g~~~) become unphysical amplitudes.
In a numerical analysis,l) we have confirmed thatthe absolute values of the unphysical amplitudes in
the large and small components agree each other forthe pseudospin pair levels, while the absolute values ofphysical amplitudes in both of large and small components agree for the spin pair levels. It is very different
from the case concerning spherical nuclei, in which thepseudospin symmetry is found in the small component,
while the spin symmetry is found in the large component. Another fact we found is that the conditions forthe pseudospin symmetry is also the conditions for the
spin symmetry in deformed nuclei. Because the deformation mixes f! and j, the deformation mixes thespin symmetry and the pseudospin symmetry in therelativistic mean field.
References
1) K. Sugawara-Tanabe, S. Yamaji, and A. Arima: Phys.
Rev. C 62, 052010 (2000).

Otsuma Women's University

25

RIKEN Accel. Prog. Rep. 34 (2001)

Delta-Hole Interaction in Nuclei and the Gamow-Teller (GT)Strength in 90Nb
A. Arima, W. Bentz,*l T. Suzuki,*2 and T. Suzuki*3[Landau-Migdal parameters, Quenching of Gamow-Teller strength, ~-hole interaction]
We performed a calculation l ) of the GT sum rulein 90Nb, using the 7r + P meson-exchange model. The
results are given in Table 1. The calculated quenching
factor (S _ /80-) is consistent with the recently measured value 2) (0.9 ± 0.05) within the error bars , if thequark-model value of the strength of the transition potential, 1t::./I7r = }72/25, is used; but for the ChewLow model value 1t::./I7r = 2 the theoretical quenching is too strong. The corresponding values for theLandau-Migdal (L.M .) parameter g~t::. are also given
in Table 1.
The 'empirical' values of g~t::., determined such as toreproduce the experimental quenching factor, are given
in Table 2. The case 'VL.M . only' corresponds to thecalculation of Ref. 3, which we extended in this workby also including the finite-range parts of the 7r + P
exchange potentials.
The resulting value of g~t::. is consistent with themeson-exchange pitcure (Table 1) within the error
bars, if the quark model value for 1t::./I7r is used,though a discepancy remains for the Chew-Low model
value. An interesting problem is whether or not these
relatively small values of g~t::. are in conflict with the

*1

*2
*3

Department of Physics, Tokai University
Department of Physics, Nihon University
Department of Applied Physics, Fukui University and

RIKEN

26

Table 1. Quenching factors and values of g~ ~.
(a) f..t:..
=
f1r

1r only
1r+P

n,

t =2

25

(b)

B-/Bo-

gN~

B-/Bo-

gN~

0.904
0.857

0.25
0.35

0.867
0.805

0.25
0.35

I

I

Table 2. ' Empirical' values of g~~.
(a) f..t:..
=fTr
VL.M. only

+V
VL .M . + V + P
VL.M.

7r

7r

n,

0.18 ± 0.09
0.26 ± 0.09
0.27 ± 0.09

25(b) ~~ = 2

0.13 ± 0.07
0.20 ± 0.07
0.21 ± 0.07

absence of pion condensation and precursor phenomena under normal conditions.
References
1) A. Arima, W. Bentz, T. Suzuki, and T. Suzuki: Phys.
Lett. B 499, 104 (2001) .
2) T. Wakasa et al.: Phys. Rev. C 55, 2909 (1997).
3) T. Suzuki and H. Sakai: Phys. Lett. B 455, 25 (1999) .

RIKEN Accel. Prog. Rep. 34 (2001)

Relativistic Hartree-Bogoliubov Approach for Nuclear Matter with
Non-Linear Coupling Terms
S. Sugimoto, *1 K. Sumiyoshi, *2 and H. Toki*l[Relativistic Hartree-Bogoli u bov theory]
We investigated the pairing property of nuclear matter using the Relativistic Hartree-Bogoliubov (RHB)
approach. We have extended the RHB approach to beable to include non-linear coupling terms of mesons.
We applied it to nuclear matter and observed the effect of non-linear terms on pairing gaps.
Recently, the relativistic mean field (RMF) theory
is being widely applied to nuclear matter and finite
nuclei. It is known that RMF theory can reproduce
nuclear properties quantitatively. 1) In RMF theory, it
is very important to include the pairing interaction on
the same footing as the density correlations. Usually,
it is implemented by the so-called BCS-type theory as
in other mean-field theory. In the BCS-type theory
the pairing interaction is implemented by hands outside of the RMF theory. However, we would like forthe pairing interaction to be described in a relativistic many-body theoretical manner within the RMF
theory. One possibility toward this attempt is therelativistic Hartree-Fock-Bogoliubov theory (RHBF),
which was formulated by Kucharek et al. 2 ) Recently,
the Hartree-Fock-Bogoliubov (HFB) theory is being
widely used in both the non-relativistic and relativistic mean-field calculations. It can treat the usual
mean field and the pairing field simultaneously. The
HFB theory has been applied to nuclear matter and finite nuclei, both relativistically and non-relativisticallywith many interesting results.
However , until now the effect of the non-linear selfcoupling terms of mesons was neglected in the pairing
channel in the RHB theory. It is known that those
non-linear terms are needed to rep rod uce the properties of nuclear matter and finite nuclei in the RMF
theory.3,4) We can suppose that those terms have someeffect on the pairing correlations. Therefore, we would
like the relativistic Hartree-Fock-Bogoliubov theory toinclude the effect of the non-linear self coupling termof mesons, and to apply it to nuclear matter to see theeffect on the pairing gap (~).
In Fig. 1 we show the pairing gap at the Fermi
momentum (kp[fm-1]) as a function of the density
measured in the Fermi momentum. We use the parameter set TMl,4) which has both 0' non-linear coupling and w non-linear coupling terms. In this figure,"With N. L." (solid line) means we include the non-<tI;'~ • • • • 'IIt..,,\,,-

With N. L.

• • •wi thout N. L.

.

,
,.
'

,#

" ..

..

....

"

,

\ ..

\,

.','

,

""
0.0

0.2

\

0. 4

1.0

.

\ ..

1.2

1.4

Fig. 1. Pairing gap (~) at the Fermi momentum (kF) in thefunction of the Fermi momentum. The TMI parameter
set is used. "With N. L." (solid line) corresponds tothe case in which the non-linear term of mesons are
implemented. "Without N. L." corresponds to the casewithout them.

linear term effect on the pairing channel and "Without N. L."(dashed line) means we do not include it.
From this figure we can see that the pairing gap is reduced by a few MeV by including the non-linear termof mesons. In our formalism the effect of the nonlinear terms appears in the propagators in the pairing
channel. It increases the mass parameters of mesonsin the propagators and reduces the interaction in thepairing channel. This effect is especially large aroundkF = 1.0 [fm- 1 ] .
We give a brief summary. A new framework has beendeveloped to incorporate non-linear terms of mesons in
the pairing channel in the RHFB theory. We have applied the RHB theory to nuclear matter to check theeffect of non-linear terms on the p-p channel. We havefound that the non-linear terms reduce ~ at the Fermi
momentum, especially for the normal-density region.
It would be interesting to apply our method to asymmetric nuclear matter or finite nuclei.
References
1)
2)
3)
4)

P. Ring: Prog. Part. Nucl. Phys. 37, 193 (1996).
H. Kucharek et al.: Z. Phys. A 339, 23 (1991).
J. Boguta et al. : Nucl. Phys. A 292 , 413 (1977).
Y. Sugahara et a l.: Nucl. Phys. A 579 , 557 (1994) .

*1 Research Center for Nuclear Physics, Osaka University*2

Numazu College of Technology

27

RIKEN Accel. Prog. Rep. 34 (2001)

Extended Renormalized Random-Phase Approximation t
N. Dinh Dang and A. Arima[Renormalized random-phase approximation, Ground-state correlations]
The set of linear equations of the random-phase approximation (RPA) is usually obtained within the quasiboson approximation, which treats the particle-hole(ph) pair-creation B~h and annihilation Bph operators as if they are bosons. This leads to a violationof the Pauli principle. As a consequence, the RPA
breaks down at a certain critical value of the interaction strength, where the RPA solution becomes imaginary. The renormalized RPA (RRPA) is an approachto correct for this inconsistency, taking into accountthe effect of ground-state correlation (GSC) beyond
the RPA. This approach has been reformulated in the
recent Ref. 1, where an improvement in the estimation of the GCS has been obtained compared to theapproach originally proposed by Hara. 2 )Recently, there has been a renewed interest in the
RRPA for its application to microscopic descriptions of
single and double beta decays. Further studies of the
RRPA and renormalized quasiparticle RPA (RQRPA)
have been reported. The studies of RRPA have so far
been limited within the ph channel, neglecting the pp
and hh interactions. In the RQRPA , this corresponds
partly to omission of the so-called scattering terms inthe model Hamiltonian, whose effect is strongest forthe particle-particle (pp) and/or hole-hole (hh) configurations. It has been suggested that the omission ofCondensed from the article in Phys. Rev . C 62 , 024303(2000)

28

such terms may be the reason of the strong violation
within the RRPA of certain model-independent sum
rules, which are well fulfilled within the RPA, such as
the Ikeda sum rule for the charge-exchange transitions.
In the present paper, the RPA is fully renormalized to take into account the GSC beyond the RPA,
which arises due to th·e fermion structure of the collective RPA operators. As compared to the conventional
renormalized RPA (RRPA) , the novelty of the present
extended renormalized RPA (ERRPA) is the inclusionof the particle-particle (pp) and hole-hole (hh) GSC
beyond the RPA along with the ph ones in the complete set of ERRPA equations. The formalism is illustrated by numerical calculations within a schematic
four-level model. The results show that the effects of
GSC beyond the RPA due to pp (and hh) transitions
can cause a partial or complete compensation of theones due to ph transitions. This reduces the deviationfrom the RPA energy-weighted sum of strength within
the ERRPA as compared to that within the conventional RRPA.
References
1) F. Catara, N. Dinh Dang, and M. Sambataro: Nucl.
Phys. A 579, 1 (1994).
2) K. Hara: Prog. Theor . Phys. 32, 88 (1964).

RIKEN Accel. Prog. Rep. 34 (2001)

Exact Form of the Random-Phase Approximation Equation
at Finite Temperature Including the Entropy Effect t
K. Tanabe* and N. Dinh Dang
[Thermal random phase approximation, Entropy effect1
Recent experimental studies of the damping of giant dipole resonances (CDR) built on hot nuclei havesupplied useful information for checking the theoretical models and methods , which have been successful
in describing the properties of the nuclear states in the
yrast region, and have been extensively applied to thehighly excited states above the yrast line. As suchan extension of microscopic formalism , the thermal
random-phase approximation (TRPA) equation l ,2) on
top of the thermal Hartree-Fock-Bogoliubov (THFB),
or the thermal Hartree-Fock (THF) solution when thepairing correlation is not important, is expected to describe the temperature-dependent behavior of the hot
CR. For this purpose, the formalism has to be guaranteed not only to smoothly tend to the ordinary RPA in
the zero-temperature limit , but also to solve the problem of the discrepancy between the TRPA matrix and
the THFB stability matrix. I)
In the present paper we have shown detailed steps
for the variational derivation of the exact thermal RPA(TRPA) equation whose matrix representation precisely corresponds to the thermal HFB (THFB) stability matrix. This equation describes an interplay
between the collective excitation and the entropy effect . It must be noticed that the extended parts of the
TRPA matrix represent the temperature effect arising from the ground state correlations modified by theexisting collective mode as well as the entropy effect.
However, the giant resonance shape is not much affected by the entropy effect unless the coupling of thecollective modes to particle-hole (ph) configurations issufficiently strong, since the entropy effect is describedin terms of the second order in the coupling constant .
Based on the energy-weighted sum rule (EWSR) extended to a finite temperature, we can point out apossibility that , in case of the CDR, the increasing
contributions arising from the entropy effect compen-sates the decreasing EWSR with temperature so thatthe sum of both contributions gives a value which does
not depend on the temperature. Making use of a simple microscopic model, we have studied the effect ofthe particle-particle (pp) and hole-hole (hh ) configurations on the Landau splitting of the CDR. We
find that these configurations play decisive roles in thetemperature-dependent phenomena of the CDR built
on a hot nucleus. The distortion of the Fermi distribution due to a temperature effect allows the damping of
CDR via the pp and hh configurations and the Landau
splitting width of the CDR increases with increasing
the temperature. Since this general mechanism works
also in the damping of CDR via four-quasiparticle configurations , it can be inferred that the increase in the
spreading width is controlled mainly by the pppp, ppph,
phhh and hhhh configurations. This physical picture
is consistent with the theoretical expectation basedon the standard TRPA in the quasiparticle picture
and the recent approaches within the phonon damping mode1. 3 ) It should be remarked that the change ofthe mean field with temperature, due to the changeof pairing correlation and deformation, which are notconsidered in the present model, are important at low
temperatures. Therefore, for the purpose of investigating the temperature dependence of CDR phenomena,
it is the most desirable to consider realistic nuclei the
TRPA calculations on top of the self-consistent solution to the thermal HFB equation.
References
1) K. Tanabe and K. Sugawara-Tanabe: Phys. Lett. B
172, 129 (1986) .
2) N. Dinh Dang: J. Phys. GIl , L125 (1985).
3) N. Dinh Dang and A. Arima: Phys. Rev. Lett . 80, 4145
(1998) ; N. Dinh Dang, K. Tanabe, and A . Arima: Phys.
Rev. C 58, 3374 (1998).

Condensed from the article in Phys. Rev. C 6 2, 024310(2000)
Department of Physics, Faculty of Science, Saitama University

29

RIKEN Accel. Prog. Rep. 34 (2001)

Electromagnetic Cross Sections of Double Giant Dipole
Resonances in 136Xe and 208Pb within
the Phonon Damping Model t
N. Dinh Dang, V. Kim Au,* and A. Arima[Anharmonicity, Double giant dipole resonance, Electromagnetic cross section]
The recent observation of double giant dipole resonances (DCDR) in heavy-ion collisions at nearrelativistic energies 1) has been a challenge for the theoretical studies of multiphonon excitations. According
to the independent-phonon (or harmonic) picture, a
DCDR is considered to be a two-dipole-phonon resonance, which is a (single-phonon) giant dipole resonance (CDR) built on top of another (single-phonon)
CDR. As such, the DCDR parameters can be calculated by folding two independent CDRs. As aresult, the DCDR energy (EDGDR) is found to be
2EGDR (EGDR is the CDR energy), and the DCDR
full width at the half-maximum (FWHM) (f DGDR )is equal to 2fGDR (fGDR is the CDR FWHM) , iffolding Lorentzian photoabsorption cross sections isused, or to J2fGDR' if Caussians are folded. The
experimentally extracted energy and width of DCDR
differ slightly from these values. The energy shift(tlE == 2EGDR - E DGDR ) is a few hundred ke V for
136Xe, while the relation J2f GDR :S fDGDR :S 2f GDR
has been observed. Anharmonicities are usually referred to as a reason for these deviations from theindependent-phonon picture. The most striking result
is that the values of the experimentally extracted crosssection of electromagnetic (EM) (or Coulomb) excitation for the DCDR are much larger than that givenby the folding model. The enhancement is found to bearound 178- 200% in reactions with 136Xe projectiles
at 700 MeV In kinetic energy, and around 133% using
208Pb projectiles at 640 MeV In kinetic energy, bombarding a 208Pb target. A number of theoretical approaches has been developed to study the multiphonon
giant resonances. Most of them can satisfactorily describe the energy, and even the width, of the DCDR,
but a simultaneous description of both the observed
CDR and DCDR cross sections is still an open question. Different theoretical models give so far the valuesof DCDR cross section, which are identical, or quite

Condensed from the article in Phys. Rev. Lett. 85, 1827
(2000)
Institute of Theoretical Physics, Vietnam. Address afterJanuary 1, 2001: Texas A & M University, USA

30

close, to that of the folding model , i. e. much smaller
than the experimental values.
Recently, an approach to the multiphonon CDR in
heavy nuclei has been proposed,2) which makes use of
the phonon damping model (PDM).3) This approachallows one to calculate microscopically the strength
function of the multiphonon CDR using the same setof PDM parameters, which have been selected to welldescribe the CDR. The calculated DCDR energy and
FWHM are found to be in reasonable agreement withthe experimental data. It has also been found that
there is a significant difference between the DCDR in
open-shell nuclei and that in closed-shell nuclei due toanharmonicities. The DGDR energy-weighted sum ofstrength in an open-shell nucleus 20Sn) is larger thanthat given by the folding model by around 30%, while
the DGDR in a closed-shell nucleus (208Pb) is foundto be rather harmonic.
In the present paper the EM cross sections of DGDR
in 136Xe and 208Pb are calculated using the strength
functions obtained within PDM. The parameters ofthe model have been selected to describe reasonably
well the single CDR in these nuclei. The results arefound to be in overall agreement with the recent experimental data for the DC DR cross sections in excl usive measurements at near-relativistic energies by the
LAND collaboration (GSI).

e

References
1) R. Schmidt et al.: Phys. Rev. Lett. 70, 1767 (1993); K.
Boretzkyet al. : Phys. Lett. B 384,30 (1996); K. Boretzky et al.: talk at the workshop on "Double Giant Resonance," '!'rento, Italy, May 10- 22, 1999, unpublished.
2) N. Dinh Dang, K. Tanabe, and A. Arima: Phys. Rev.
C 59, 3128 (1999); Nucl. Phys. A 675 , 531 (2000).
3) N. Dinh Dang and A. Arima: Phys. Rev. Lett. 80,
4145 (1998), Nucl. Phys. A 636, 443 (1998); N. Dinh
Dang, K. Tanabe, and A. Arima: Phys. Rev. C 58, 3374
(1998).

RI KEN Accel. Prog. Rep. 34 (2001)

Angular-Momentum Effect on the Widthof the Hot Giant Dipole Resonancewithin the Phonon Damping Model
N. Dinh Dang, A. Ansari,* and A. Arima[Angular momentum, Giant resonances, Thermal and statistical models]One of the important issues in studying the giant
dipole resonance (GDR) built on highly excited nuclei(hot GDR) is to separate the effects due to the temperature (T) and angular momentum (J) on the GDR
width. Inelastic a-scattering measurements in 120Sn
and 208Pb have shown that the increase in the GDR
width with increasing T up to T ~ 3.2 MeV is mainly
a temperature effect, since their results, obtained at an
averaged (J) of rv 5- 20 n, coincide with the heavy-ion
fusion data obtained at (J) rv 20- 45 n. Meanwhile,the inclusive heavy-ion fusion measurements of GDR
in lighter tin isotopes, l06,109,l10 Sn , at T ~ 1.8 MeV 1)
show an increase in the GDR width by rv 2 MeV as
J increases from 40 to 54 n. The angular-momentum
effect on the GDR width was studied by several approaches, where the increase in the GDR width as afunction of J is induced by averaging over the intrinsic
degrees of freedom that describe the thermal fluctuations of the quadrupole shapes.
In the recently developed phonon damping model(PDM),2,3) it has been shown that the mechanism responsible for the temperature dependence of the GDR
width is the coupling of the GDR phonon to particleparticle and hole-hole configurations, which appear
due to the fact that the Fermi surface is deformed at
T f; O. This allows the PDM strength functions to
be calculated directly in the laboratory frame without
any need for an explicit inclusion of the thermal fluctuations of shapes. The PDM is the only up-to-datemodel that can give a simultaneous and satisfactory

description not only for the GDR width,1) but also
for its shape,4) as well as the integrated yields of ,emission3) as a function of T in good agreement withrecent experimental data. It is also the only model
which can give a consistent description for both thewidth's increase at low T ::; 3 MeV and the width's saturation at high T 2: 4 MeV. The angular-momentum
effect has not yet been taken into account in the PDM.
In this work the effect of angular momentum on thewidth of GDR in highly excited nuclei was studied
within the phonon damping model by introducing aneffective temperature (T) as a function of the nuclear
temperature (T) and angular momentum (J). The results of numerical calculations for the GDR's width in
l06Sn obtained at T = 1.8 MeV as a function of J are
in good agreement with the recent experimental data.
The angular-momentum effect on the GDR width decreases with increasing T and vanishes at T > 4 MeV,
where the width saturates.
References
1) A. Bracco et al.: Phys. Rev. Lett. 74, 3748 (1995); M.
Matiuzzi et al.: Nucl. Phys. A 612, 262 (1997).
2) N. Dinh Dang and A. Arima: Nucl. Phys. A 636, 427(1998).
3) N. Dinh Dang, K. Tanabe, and A. Arima: Nucl. Phys.
A 645, 536 (1999).
4) N. Dinh Dang, K. Eisenman, J. Seitz, and M.
Thoennessen: Phys. Rev. C 61, 027302 (2000).

Institute of Physics, Bhubaneswar, India

31

RIKEN Accel. Prog. Rep. 34 (2001)

Thermal Shape and Orientation Fluctuation Corrections
for the Hot Giant Dipole Resonance within
the Static Path Approximation
A. Ansari ,* N. Dinh Dang, and A. Arima
Giant ~ipo~e resonance , Thermal fluctuations of shapes and orientations, Static path][ approXImatIOn
The study of the giant dipole resonance (GDR) at
high temperatures and spins is still an active area ofinvestigations both experimentally and theoretically.
There is a need for a fully microscopic approach that
employs an effective many-body Hamiltonian, which
can reproduce the dependence of the GDR width (f)and the shape as a function of the temperature (T) andspin (J). Recently, a microscopic scheme was proposed
in Ref. 1 in which the ,),-absorption cross section (7 (E))
as a function of the ')'-ray energy (E) is computed in thelinear-response theory at finite temperature with averaging over the fluctuating shape parameters within thestatic path approximation (SPA) to the grand canonical partition function. The angular-momentum dependence is included following the standard cranking
approach. Very recently,2) we applied this approachto study the GDR parameters in 120Sn. It was foundthat although the increase of f with T is very week,
the average over the shape fluctuations within SPA canprovide a reasonable dependence on J. However, corrections for the fluctuation of the orientation angles of
the rotational axis were not included.
As a continuation of the above-mentioned work, wehave attempted here to investigate the effect of theorientation fluctuation corrections with numerical calculations performed for lO~Sn. Because this nucleus islighter than 120Sn, we expect a stronger dependence

Institute of Physics, Bhubaneswar, India

32of f as well as of the average of deformation parameters on the angular momentum. The ,),-absorption
cross section of 106Sn is calculated at temperature
T = 2 MeV and angular momenta J = 40 and 55 1i following the linear response theory at finite temperatureand incorporating the thermal shape as well as orientation fluctuation corrections within the SPA. The
orientation fluctuation corrections have been included
for the first time in such a calculation, and are foundto be rather unimportant. Then, the GDR was calculated without these effects at several more temperatureand spin values. We find that at T = 4MeV the GDR
width (f) shows an increase of only about 1.5 MeV
compared to its value at T = 0.5 MeV. However, at a
fixed temperature of T = 2 MeV , the increase in thewidth at J = 691i is by about 3 MeV compared to its
value at J = O. Finally, we also compared the increaseof f at T = 2 Me Vasa function of J for 106 Sn and120Sn . The increase is steeper for the lighter isotope ,as expected.
References
1) B. K. Agrawal, A. Ansari, and P. Ring: Nucl. Phys. A
615 , 183 (1997).
2) A. Ansari, N. Dinh Dang, and A. Arima: Phys. Rev. C
62, R011302 (2000).

RIKEN Accel. Prog. Rep. 34 (2001)

Adiabatic Selfconsistent Collective Coordinate Method forLarge-Amplitude Collective Motion t
M. Matsuo,*l T. Nakatsukasa, and K. Matsuyanagi*2[Nuclear structure models and methods, Hartree-Fock and random-phase approximations]
Large-amplitude collective motion (LACM), such as
fission, shape transitions, anharmonic vibrations andlow-energy heavy-ion reactions, are often encounteredin studies of nuclear structure and dynamics. Many
attempts have been made to construct theories thatare able to describe the LACM on a microscopic basis of the nuclear many-body Hamiltonian. In particular, theories based on the time-dependent Hartree-Fock(TDHF) approximation have been extensively investigated. TDHF is a general framework for describing
low-energy nuclear dynamics accompanying evolutionof a nuclear self-consistent mean field. LACM corresponds to a specific solution of the TDHF equationof motion. Since such a solution forms only a subsetof all the TDHF states (Slater determinants) , it is often called a collective path, a collective subspace, ora collective submanifold. The collective coordinates
are then a set of a small number of variables that parameterize the collective subspace, and the collective
Hamiltonian is a function governing the time evolution of the collective coordinates. One of the main
purposes of the LACM theories is to provide a scheme
to determine the collective subspace and the collective
Hamiltonian on the basis of a microscopic many-body
Hamiltonian. Although studies of LACM theories forma vast field of research with many recent developments
in different directions, realistic applications to nuclear
structure problems have been very few.
The adiabatic approximation has often been utilized to formulate a theory of the collective subspace.
The adiabatic TDHF (ATDHF) theoryl) is one of
the best-known adiabatic theories. The ATDHF theory, however, had a problem of non-uniqueness of thesolution. 2) Efforts to settle the non-uniqueness problem have been made and summarized in a consistent
way in the formalism of Ref. 3. However, a problemof particle-number conservation arises when applied
to superconducting nuclei (i. e. , nuclei with pairingcorrelations).4)
Theories without an adiabatic approximation havealso been developed within the TDHF framework. The
early studies in this direction are called local harmonic
approximations. Later, a set of general equations
that can be used to determine the collective subspace
and the collective Hamiltonian were found and formulated in a consistent form , known as the self-consistent
t
*1

*2

Condensed from the article in Prog. Theor. Phys. 103, 959(2000).
Graduate School of Science and Technology, Niigata Univ.
Department of Physics, Kyoto University

collective coordinate method (SCC or SCCM).5) The
theory is purely based on the TDHF with no further approximation. The pairing correlation in superconducting nuclei is easily incorporated within the
SCCM by adopting the time-dependent Hartree-FockBogoliubov (TDHFB) equation in place of the TDHF ,and the conservation law for the particle number isconsistently introduced within the basic framework of
the SCCM.6) However , since the method relies upon an
expansion with respect to the collective coordinates, it
may not be suitable for the large-amplitude motion ofan adiabatic nature, for which the change in the nuclear mean-field is so large that a power-series expansion of the collective coordinates may not be justified.
In this work, we attempted to combine the meritsof the two approaches mentioned above, the SCCM
and the adiabatic theory, in order to formulate a theory that provides a consistent and practical methodthat is easily applicable to realistic descriptions of theadiabatic LACM in superconducting nuclei. We haveachieved this by introducing an adiabatic approximation within the general framework of the SCCM. Here,
we treat superconducting nuclei, since the pairing correlations play essential roles in many cases, like spontaneous fission, tunneling between superdeformed andnormally deformed configurations, and coupling between coexisting states with different nuclear shapes(shape-coexistence phenomena) . Although the useof the superconducting mean field requires particlenumber conservation to be respected , the SCCM allows a simple and consistent treatment of the conservation law. We also avoid the non-uniqueness problem
by utilizing principles similar to those of Ref. 3. Furthermore, we show that the equations of the adiabatic
SCCM thus formulated can be transformed into another set of equations that have a similar structure
as that of the local harmonic approach in adiabatic
theories. 3 )References
1) F. Villars: Nucl. Phys. A 28 5 , 269 (1977).
2) A. K . Mukherjee and M. K . Pal: Phys. Lett. B 100,457(1981).
3) A. Klein , N. R. Walet , and G. Do Dang: Ann. Phys.
208 , 90 (1991).
4) T. Nakatsukasa, N. R. Walet, and G . Do Dang: Phys.
Rev . C 61, 014302 (2000).
5) T. Marumori , T. Maskawa, F. Sakata, and A.
Kuriyama: Prog. Theor. Phys. 64, 1294 (1980) .
6) M. Matsuo: Prog. Theor. Phys. 76 , 372 (1986).

33

RIKEN Accel. Prog. Rep. 34 (2001)

Microscopic Description of Damped Collective Motion t
S. Yamaji, H. Hofmann,*1 and F. A. Ivanyuk*2[Linear response theory, Giant dipole resonance, Fission]
The dissipation of nuclear matter and its evolution
as a function of temperature is one of the fundamental
properties of nuclear matter.
In the case of the fast collective motion of the isovector mode, the damping mechanism of the giant dipole
resonances as a function of spin and temperature has
been highly debated. Reviews are given, for example,
in Refs. 1 and 2. The theoretical models which areused at present to explain the temperature dependence
are the two-body collisional damping model (see, forexample, Ref. 3 for collisional damping to the 2p-2h
states in the Landau-Vlasov equation, Ref. 4 for collisional damping to the Ip-lh + 1 phonons states, Ref. 5
for collisional damping to 2-phonon states) and thethermal fluctuation model (see, for example, Ref. 6).
Whether the temperature dependence arises from collisional damping of nucleons or from thermal fluctuations of nuclear potential landscape is still unclear.
Studies of the giant dipole resonance based on transport theory,7) in which the collisional damping to the
2p-2h states is treated , will shed light on this debate.
As for isoscalar modes at finite excitations, the best
information available at present comes from experiments on fission accompanied by the emission of lightparticles or gamma rays. Nowadays, it seems possible
to obtain information on the effective damping rate,'rJ = ,),/(2vM ICI), at the saddle and its temperaturedependence 8- 10 ), where the coefficients ,)" M and Carefriction, inertia and local stiffness, respectively. Theyfind an 'rJ which increases markedly with T. Such behavior is hard to understand within the macroscopic
models (see, for example, Ref. 11).
In the present work,12) the damping mechanism of
the damped collective motion is being studied microscopically on the basis of linear response theory. 7)
As for isovector modes , the calculated strength function of the giant dipole resonance built on highly excited states in 208Pb is compared with the observed
one. 13 ) It is found that our two-body collisional damping model almost reproduces the temperature dependence of the observed width, indicating little room fora contribution due to the thermal fluctuation mode1. 6 )

*1
*2

34

Condensed from the article in Proc. Tours Symp. on Nuclear
Physics IV , Tours, France (4-7, Sep. , 2000)
Physik-Department der Technischen Universihit Miinchen,
Germany
Institute for Nuclear Research of the Ukrainian Academy of
Sciences, Ukraine

As for isoscalar modes, slow collective motion likefission, is studied. The calculated effective damping
rate 'rJ at the saddle is in qualitative agreement withthe observed one, which increases markedly with thetemperature. A more realistic description of solving
the transport equation (see, for example, Ref. 14) is
necessary to obtain quantitative agreement. The approximate functional form of the friction is provided
for that.
Moreover, it is noticed that the effect of the shellstructure on the friction should be taken into accountas well as the shell correction energy in theoretical estimate of the production of supper-heavy elements basedon the transport equation.
References
1) K. A. Snover: Annu. Rev. Nucl. Part. Sci. 36, 545(1986).
2) J. J. Gaardhoeje: Annu. Rev. Nucl. Part. Sci. 42 , 483(1992).
3) V. Baran, M. Colonna, and M. Di Toro et al.: Nucl.
Phys. A 599, 29c (1996).
4) P. Dontai, N. Giovanardi, P. F. Bortignon, and R. A.
Broglia: Phys. Lett. B 383, 15 (1996).
5) N. Dinh Dang, K. Tanabe, and A. Arima: Phys. Rev.
Lett. 80, 4145 (1998).
6) W. E. Ormand, P. F. Bortignon, R. A. Broglia, and A.
Bracco: Nucl. Phys. A 614, 217 (1997).
7) S. Yamaji, H. Hofmann, and R. Samhammer: Nucl.
Phys. A 475 , 487 (1988).
8) P. Paul and M. Thoennessen: Annu. Rev. Nucl. Part.
Sci. 44, 65 (1994).
9) D. J. Hofman, B. B. Back, and P. Paul: Phys. Rev. C
51 , 2597 (1995).
10) I. Dioszegi, N. P. Shaw, I. Mazumdar et al.: Phys. Rev.
C 61 , 024613 (2000).
11) J. Blocki, Y. Boneh, J. R. Nix, A. J. Sierk, and W. J.
Swiatecki: Ann. Phys. 113, 330 (1978).
12) S. Yamaji, H. Hofmann, and F . A. Ivanyuk: Proc.
Tours Symp. on Nuclear Physics IV, Tours, France (4-7,
Sep., 2000).
13) T. Baumann et al.: Nucl. Phys. A 635 , 428 (1998).
14) T. Wada, Y. Abe, and N. Carjan: Phys. Rev. Lett. 70 ,3538 (1993).

RIKEN Accel. Prog. Rep. 34 (2001)

Effects of Nuclear Rotation on the Collective Transport Coefficients
F. A. Ivanyuk* and S. Yamaji[Linear response theory, Friction, Nuclear rotation]
The recent success of the Flerov Laboratory, JINR,
Dubna in the synthesis of the superheavy element with
Z = 114 has provoked considerable theoretical interest in fusion-fission reactions at low excitation energies. Commonly, such reactions are described bysolvingl) the Langevin equation for the collective variables which specify the shape of the compound system.
Usually, such systems are formed with a rather highangular momentum. However, the effect of rotationon the shell correction, as well as friction and inertia,
is completely ignored at present, though one might expect a considerable dependence of the transport coefficients on the rotation, since the rotation greatlychanges the single-particle spectrum. This effect was
analyzed only in Ref. 2 where a rather strong dependence of the friction coefficient on the angular velocity
was found.
To examine the influence of rotation on the potential energy and transport coefficients, we modified thetwo-center shell model code by taking into accountthe effects of nuclear rotation. We found that theshell correction is rather stable to nuclear rotation (seeFig. 1). The friction I and mass M parameters computed within the linear response theory 3,4) turned out
to be rather sensitive to such a fine effect as the violation of rotational symmetry by the Coriolis term,-wrotJx .

To remove the spurious contributions to the transport coefficients, we modified the model of "uniform
rotation" and introduced a time-dependent rotationalfrequency. A similar method was used in Ref. 5 to remove the spurious contributions to the response functions caused by a violation of the particle-number conservation by pairing forces. In the result we obtained
the friction and mass, which demonstrated rather reasonable dependence on the rotation (see Fig. 2) . For
excitations above T = 2 MeV, where the microscopic
shell effects disappear, both I and M are rather insensitive to rotation. For 1 Mev ::; T ::; 2 MeV , wefound some increase of I and M with growing Wrot.
Such an effect might be caused by a change in the shellstructure due to a re-arrangement of the single-particle
states by rotation.
Even a stronger dependence of I and M on Wrotshould be expected for T ::; 1 MeV when both the shelland pairing effects are present. As shown,5 ,6) the pairing effects change considerably the collective transport
at low excitations. The destruction of pairing by rotation can have a considerable effect on the final stage

2,,--...

>Q)

1

2-0
LL
'0 -1

T= 1 MeV

-2

5

10

15

20

Zo (fm)Fig. 1. Shell correction, of = oR - ToS, to the free energy
for temperature T = 1 MeVasa function of the deformation parameter Zo. The solid, dashed, dotted-dashedand dotted correspond to the values of the rotational
moment equal to 0, 20, 40 and 6011,.

,,--... 4.0

22 4 Th •sadd le.c"-....

>Q)~ 3 .02"-....

r- 2 .0

1.0 . '="'
6 ''--1' ---'------'----'---'---'---............---'--::-2.~0-'--'---'---............---'------'----'-~
3.0
1

T (M eV)Fig. 2. Reduced friction coefficient, j3 = ,1M, versus temperature. The dotted, dashed and solid curves correspond to the values of the rotational moment equal to0, 40 and 60n.

of the fusion reaction and the formation of superheavy
elements, which takes place at low excitation energy.
References
1) Y. Abe et al: Phys. Rep. 2 75 , 49 (1996).
2) K. Pomorski and H. Hofmann: Phys. Lett. 26, 164(1991).
3) H. Hofmann: Phys. Rep. 28 4, 137 (1997).
4) S. Yamaji et al: Nucl. Phys. A 475 , 487 (1988).
5) F . Ivanyuk and H. Hofmann: Nucl. Phys. A 657, 19(1999).
6) H. Hofmann and F . Ivanyuk: Phys. Rev. Lett. 82 , 4603
(1999).

Institute for Nuclear Research, Ukraine

35

RIKEN Accel. Prog. Rep. 34 (2001)

Fusion Probability for a Multi-Dimensional Dissipative Barrier
Y. Abe,*l J.-D. Bao,*2 D. Boilley,*3 and T. Wada*4[Heavy ion fusion, Dissipative barrier , Effect of neck formation]
In the fusion process of massive systems, such as
86Kr+208Pb, with which a Berkeley group claimed tosynthesize Z = 118 superheavy elements,!) not only
the usual Coulomb barrier, but also the conditional
saddle, must be overcome. As for the latter, thepassing-over probability is much smaller than a simple
barrier penetration for the saddle-point height, leading
to what is called fusion hindrance. 2) The reason is thatthe kinetic energy of the collective motion provided
by the incident energy dissipates very quickly into
thermal energy, i.e. , nucleonic motions, following thecompound-nucleus concept by N. Bohr. 3) Therefore,much more energy must be injected than the apparent
height of the saddle point. Since there are collective degrees of freedom with heavy inertia mass and nucleonicdegrees of freedom quickly thermalized, we can employ the theory of Brownian motion, i.e., dissipationfluctuation dynamics for collective motions, more precisely, Langevin equation, Kramers equation etc. 4 )An analytic solution for a general multi-dimensional
parabolic barrier with dissipation has been given by
Y. Abe et al.,5) where the probability for passing-over,i. e. for fusion, is given simply by the error function. In
the one-dimensional case, the extra-push energy which
describes the fusion hindrance is given by the following
simple expression:

E extra =(i1 :,!') B ,
2 .

(1)

where j3 denotes the reduced friction, "y 1m, and j3' =j32 + 4w 2 with w being the curvature of the saddle
point. B is the height of the saddle measured from theenergy of the initial point, i. e., the contact configuration of the incident ions. From this expression, one canreadily understand that E extra is much larger than B
if j3 » w, which is the case with the one-body model 6)
for friction.
The real fusion process would not be described wellby a one-dimensional model. It is naturally understoodby considering possible shape variations which areparameterized with the fragment distance, the mass
asymmetry, the neck radius, etc. This indicates thata one-dimensional treatment is an over-simplification
and underestimates the probability for reseparation,
since there are many possible trajectories sliding downalong the multi-dimensional valley back to reseparation, not only along the fusion direction. Therefore,

J

*1

*2
*3

*4

36

Yukawa Institute for Theoretical Physics , Kyoto University
Department of Physics , Beijing Normal University, China
GANIL , France
Department of Physics , Konan University

we must take into account the effect properly, but witha reasonal simplicity being maintained.
As a first step, we attempt to take into account theeffect of the neck-degree of freedom. Since the barrierheight , B, from the contact point depends on the neckparameter, e, the fusion probability, Pjus( E c.m.), is
given bywhere p(e) denotes the distribution of the neck parameter, e, in contact configurations. Extra-push energy
is now obtained by the condition that Pjus(Ec.m.) of
Eq. (2) be equal to 1/2, instead of Eq. (1), which is
obtained with Pjus( Ec.m., B) on the right-hand sideof Eq. (2). The problem is how to obtain a distribution, p(e) , which is actually time-dependent. Thus , wemust solve a time-evolution of the neck, assuming initial conditions of c(t = 0) = 1.0 and t(t = 0) = 0.0.
The evolution is again described by a Langevin equation,(3)
where iE = -auI ae is approximated to be constantfrom the liquid-drop model energy surface. 7) r E (t) denotes a random force which is assumed to be Gaussianand Markovian. An essential assumption underlying
Eq. (3) is that the e-degree of freedom is treated withno coupling to the radial motion. The distribution,p(e) , would be given byp(e)=Co·exp ( -

(e -

t)2)

20'2

'

(4)

where E and 0' are time-averages of the average andthe variance of the trajectories over the fusion time.
Such an approach leads to a better agreement with theexperimental results,8) for example the looMo-looM osystem.
References
1) V. Ninov: Phys. Rev. Lett. 83 , 1104 (1999).
2) S. Bjornholm and W. J. Swiatecki: Nucl. Phys. A 391 ,
471 (1982).
3) N. Bohr: Nature 137, 344 (1936) .
4) Y. Abe et al.: Phys. Rep. C 275 , 49 (1996).
5) Y. Abe et al. : Phys. Rev. E 61 , 1125 (1999).
6) J. Blocki et al. : Ann. Phys. 113, 330 (1978).
7) K. Sato et al.: Z. Phys. A 290, 145 (1979).
8) J. D. Bao, D. Boilley, T. Wada, and Y. Abe: to be
published.

RIKEN Accel. Prog. Rep. 34 (2001)

Dynamics of Contact in 86Kr+208Pb Collisions
Y. Abe*I and G. Kosenko*2[Superheavy elements, Heavy ion fusion, Surface friction model]
Recently, 86Kr+208Pb collisions have been used forsynthesizing the Z = 118 superheavy element at
Berkeley. 1) In order to theoretically obtain residue
cross sections in such massive systems, it is necessary
to calculate the fusion probability, Pjusion, by taking into account both the processes of passing overthe usual Coulomb barrier and the conditional saddle.
In lighter systems, the former process is sufficient for
Pjusion, but in massive systems the latter process plays
a crucial role for Pjusion, as discussed with the extrapush or extra-extra-push energy. Therefore, Pjusion is
given by the following product:
Pjusion= Pcontact . Pjormation,

1,0
86 Kr

0,8

rly.t:.-

0,6

aII.....J

"

P'

~
rI

-~ 0,480...

~"""'"+ 208 Pb

..•.

0,2

.J

0,0

o

150

100

50

200

250

300

(1)

where Pcontact denotes the probability for the incident
system to reach the matter contact, passing over theusual barrier, and Pjormation denotes that for a composite system (connected di-nucleus system) to reacha spherical compound nucleus, passing over the conditional saddle under strong competition with the socalled quasi-fission and fast-fission. Pjormation should
be calculated by solving the dissipation-fluctuation dynamics of the collective motions, which has not yet
been made on the present system, but made on othersystems. 2)
In order to perform a dynamical calculation for
Pjormation correctly, the initial conditions are necessary, such as how much flux has overcome the Coulomb
barrier, how much incident energy has dissipated into
internal excitation, etc. These are included in the first
factor, P contact.
In the present work, the authors have started to obtain Pcontact by employing the so-called surface friction
model,3) and have solved a number of classical trajectories up to the contact point for 86Kr+ 208 Pb collisions
with the incident energy being above the Coulomb barrier.
Physically important points are (i) how much flux
can reach the contact point of two nuclear droplet,i.e., at a relative distance equal to the sum of theradii, and (ii) how much energy dissipation, or what isthe contact state. Figure 1 shows preliminary resultsfor Pcontact, the probability of reaching the contact
point as a function of the energy. Figure 2 shows theradial-momentum distribution at the contact point,
from which the radial motion is known to almost reachthermal equilibrium.

Fig. 1. Contact probability as a function of the incident
c.m. energy measured from the Bass barrier, B Jus.

B6

Kr + 20B pb ,E'ab=450 MeV

5000

i\" ••

4000

I

3000

I

en

I

> 2000
Q)

J

1000

J

0
-6

-4

I

.•,

\

I

•

EQ)

• L=5

•II

,•

.I

·•••,
•

•

"-

-2

0

2

4

6

radial momentum

Fig. 2. Distribution of the radial momentum at the contact
point r = R12 = R1 + R2 at Elab = 450 MeV, where
the initial momentum at the barrier top is just outsideof the y-axis.

References
1) V. Ninov et al.: Phys. Rev. Lett. 83, 1104 (1999).
2) Y. Abe et al.: Phys. Rep. 275, 49 (1996); T. Wada etal.: Proc. DANF98, edited by Y. Oganessian, J. Kilman,
and S. Gmuca, (World Scientific, 1999), p.77.
3) D. H. E. Gross and H. Kalinowski: Phys. Rep. 45, 175(1978).

*1 . Yukawa Institute for Theoretical Physics, Kyoto University*2

Department of Physics, Omsk University, Russia

37

RIKEN Accel. Prog. Rep. 34 (2001)

New Nuclear Reaction Flow during r-Process Nucleosynthesis inSupernovae: The Critical Role of Light Neutron-Rich Nuclei t
M. Terasawa,*l K. Sumiyoshi,*2 T. Kajino,*3 G. Mathews,*4 and 1. Tanihata[r-Process, Supernova]
For an r-process study, a reaction network with
10 :S Z :S 94 has usually been adopted for a longtime. However, in a very neutron-rich environment,
their network can be too narrow for the light-nuclei
region. We have therefore extended a network up to
the neutron-drip line (see dots in Fig. 1). We compared the final abundance patterns with and without
this extension of the network (called 'full network' andthe 'small network'). As for 10 :S Z :S 94, we used thenuclear reaction network of Meyer et al. 1)
We employed the v-driven wind models of Sumiyoshi
et al. 2 ) We chose the case in which the expansion
timescale is as short as Tdyn = 0.005 sec (the massof neutron star, MNS = 2.0M 0 ; radius, RNS =10 km and; total neutrino luminosity, Lv ,total = 6 X
10 52 erg/sec). We started a network calculation fromthe time when the temperature drops to T = 9.0 x
109 K and set the time to t = 0.0 sec at this time. The
initial electron fraction, Ye = 0.42, is taken from hydrodynamical simulations.
It is considered that the r-process path runs throughnuclei with almost the same neutron separation energy,
Sn = 2- 4 MeV, at freezout. In the present analysis using our 'full network,' the corresponding Sn-value isabout 1 MeV. This result indicates that the r-process
path runs through a more neutron-rich region. The rprocess path is displayed in Fig. 1 at time t = 0.57 sec.
At this time, T = 0.62 x 109 K and the matter density is 5.4 x 10 2 g/cm 3. Abundant nuclei are shown by
open circles, whose diameters are proportional to theabundance yields. The main reaction path.is indicatedby arrows.
Figure 2 shows the final abundance distribution.
The solid and dotted lines in this figure are the results obtained by using the 'full network' and 'small
network,' respectively. The data points are the solarsystem r-process abundances from Kappeler et al. 3 ) inarbitrary units. The main reason for this difference
between the two cases is that a new nuclear reaction
flow opens in the light neutron-rich nuclei. 4)
References
1) B. S. Meyer, G. J. Mathews, W. M. Howard, S. E.

*1
*2
*3
*4

38

See Terasawa et al. 4 ) for more details
University of Tokyo
Numazu College of Technology (NCT)
National Astronomical Observatory (NAO)
University of Notre Dame, USA

20t0.567 (sec)

15
N

10
5

0

8

0

YA = 10- 1 10- 5 10- 10

0

5

10

15

N

20

25

30

Fig. 1. Abundances and main path for Z :::; 15.

10Q)

g10- 5cu"d§ 10,.0<C

10 10 - 8LL~-L~~~~-L~~~~~~~~~~

o

50

100
150
200
Mass Number

250

Fig. 2. Final abundances as a function of mass number.

Woosley, and R. D. Hoffman: Astrophys. J. 399 , 656(1992).
2) K. Sumiyoshi, H. Suzuki, K. Otsuki, M. Terasawa, andS. Yamada: Publ. Astron. Soc. Jpn. 52 , 601 (2000).
3) F. Kappeler, H. Beer, and K. Wisshak: Rep. Prog. Phys.
52 , 945 (1989).
4) M. Terasawa, K. Sumiyoshi, T. Kajino, I. Tanihata, and
G. Mathews: submitted to Astrophys. J. (2001).

RIKEN Accel. Prog. Rep. 34 (2001)

Video: "The Quest for the Origin of the Elements"
Y. Mochizuki, L Tanihata, and Y . Yano
[Nucleosynthesis]
The authors have produced a video on nucleosynthesis in the Universe. The primary characteristic of thisvideo is that we have employed a number of 2-D and
3- Dimensional visualizations and animations based on
an updated understanding of nuclear physics and astrophysics. An outline is given as follows.
Title: "The Quest for the Origin of the Elements"
Planning: RIKENSupervision: Y. Mochizuki, L Tanihata,.and Y. Yano
Production: Image Science, Inc.
Time Length: 29' 00" [Restricted by a contract tobe broadcast by a program on "Science Channel."]Fig. 1. Solar system abundances are shown by logarithmic
scale on the z-axis on the chart of the nuclides.

Type: VHS
Language: Japanese
Target: High-school students intending to take a science course and upward.
Purpose: (1) To bring new researchers into the fields
of nuclear physics and astrophysics.
(2) To be used for education in universities and highschools.
(3) Accountability for the RI-Beam Factory Project.
Contents: Chart of the nuclides, Nuclear burningin the Sun, Big-Bang nucleosynthesis , Stellar nucleosynthesis, Heisenberg's valley, The s-process, The rprocess, Production of an RI beam, etc.

Fig. 2. Heisenberg's valley. The experimental (A < 8)
and a set of theoretical (A 2 8) atomic mass data areadopted.

Interviewees: Professors K. Sato, T. Kajino, L
Tanihata, D. Arnett, C. Sneden, K. Langanke, and
F.-K. Thielemann.
Theoretical Data are Provided by:
Doctors
T. Tachibana (for the r-process and the following beta
decays), H. Koura (for Heisenberg's valley, chart of thenuclides), K. Kohri (for Big-Bang nucleosynthesis), H.
Umeda (for the evolution of the onion-like shell structure of a 15 M0 star) , T. Shimizu (for a numericalsimulation of a supernova explosion).
One of the Emphasized Points:
Microscopic
physics (i.e., nuclear physics) and macroscopic physics( i. e., astrophysics) are strongly related.

Fig. 3. The r-process path is demonstrated on the z-axis
by Log-scaled abundances on the chart of the nuclides.

Distribution: Under discussion. Pamphlets for explanation will be prepared.

39

RIKEN Accel. Prog. Rep. 34 (2001)

Nuclear K Bound States in 3He and 4He
Y. Akaishi * and T. Yamazaki[Kaon bound states, Strangeness]
We have investigated theoretically the possible existence of deeply bound nuclear states of K in few-bodysystems. We first constructed phenomenologically aquantitative KN interaction model as simple as possible by using free KN scattering data,1) the X-ray
data of kaonic hydrogen atom 2 ) and the binding energy and the width of A(1405) which can be regarded
as an isospin I = 0 bound state of K + N. Then, theI = 0 and I = 1 KN interactions, vkN(r) , vkN ,7rE(r)and vkN ,7rA (r), are determined. The potential range is
set to be the proton size, 0.66 fm. The I = 0 interaction produces the unstable bound state of A(1405) with
Ef(N = -29.5 MeV (-27 MeV) from the 1=0 threshold (from the K- +p threshold) and r = 40 MeV.
The KN g-matrix in nuclear medium is calculatedby the g-matrix method , where the binding effects of
K and N are properly taken into account. Now wesearch for nuclear K bound states in 3He and 4He. By
using the normal density distributions we calculate thebound state energies Ef( in such a way that Est, gI
and Ef( become self-consistent. The obtained results
are Ef( = -76 MeV and r = 82 MeV for kH (T = 0),
and Ef( = -69MeV and r = 66MeV for i<H. The
bindings are fairly large as expected, but the widths
are also large, since the bound states are located abovethe ~ + 7r threshold.
Due to the strong KN attractive force the bound K
is expected to act as a kind of glue to combine thenucleons closer. Of course, such a shrinkage effect induced by K must be counterbalanced by the strong
incompressibility of the core nucleus.
The final results of this size-optimization procedureshow substantial lowering of the bound state energies
and shrinkage of the core nuclear radii. Figure 1 depicts the optimized K-nucleus potentials Uf( of the K+ 3He and K - + 4He systems with the bound statesof kH and of i<H, which are extensions of the basic
K- + p system with A(1405) as its bound state. The
predicted bound states are expected to have narrow
widths because the states are below the ~7r emission
threshold .
Now let us show that kH (T = 0) may be formed
and identified in K- absorption at rest by 4He. The
K - in an atomic orbit falls into the deeply-bound nuclear orbit of kH (T = 0), emitting a neutron whichhelps to form the core nucleus with one neutron lessand simultaneously serves as a spectator of the formed
state. As shown in Fig. 2, the energy of the emitted
Institute of Particle and Nuclear Studies, High Energy Accelerator Research Organization

40

U~UCI

U!,ucl

K

K

MeV

MeV

-500

-500

U_nucI
K

MeV

-500

Fig. 1. Calculated K-N and K-nucleus potentials and thebound levels , A(1405) , kH and kH for the K - -p, _3He
and -4He systems, respectively. The nuclear shrinkage
effects are taken into account.

[ K-®3He + K~H]
T=O
-1 50

Fig. 2. Energy level diagram of the K- +3He system. The
T = 0 state can be excited and signaled with a discrete
neutron emission from stopped K - on 4He. The calculated neutron spectral intensity (branching ratio) is
also shown.

neutron is related to the K binding energy.
References
1) A. D. Martin: Nucl. Phys. B 179, 33 (1981) .
2) M. Iwasaki et al. : Phys. Rev. Lett. 78, 3067 (1997); T.
M . Itoh et al.: Phys. Rev . C 58, 2366 (1998).

RIKEN Accel. Prog. Rep. 34 (2001)

Empirical Deduction of a Medium-Modified Quark Condensate from
Deeply-Bound Pionic States in Heavy Nuclei
P. Kienle* and T. Yamazaki[Pion-nucleus interaction, Nuclear medium effect, Quark condensate]
Although how the hadron properties (mass andstructure) are modified in nuclear medium is one of thecentral problems of hadron nuclear physics, no clear
evidence has been available, because of lack of suitable procedures to deduce the in-medium properties
from the experimental observables. Recently, a new
type of nuclear spectroscopy, namely "hadron mass
spectroscopy," has evolved in connection with deeplybound pionic states,l) and will be extended to otherhadrons. Following the first successful experiment on
the 208Pb(d, 3He) reaction to populate the 2p and Is
7[- states in 207Pb,2) a refined experiment has been
carried out on the 7[- 0 205Pb. 3) Further experiments
on Sn isotopes will also be carried out soon. Here,
we discuss how to obtain information on a possible
quark condensate from the experimental data of deeply
bound pionic states.
The isovector b1 parameter in the pion optical potential is related to the pion decay constant throughthe Tomozawa-Weinberg relation,4)(1)
The pion decay constant (fn:) is the order parameter ofchiral symmetry breaking of QeD and is related to aquark condensate ((qq)) through the Gellmann-OakesRenner relation,5)(2)
where mq = (mu + md)/2 is the average of the u andd quark masses. If in: and (qq) are modified in the
nuclear medium to i; and (qq)*, respectively, they arereflected in the isovector parameter (b 1 ) of the pionnucleus potential. Thus, it is essentially important tosee how the isovector part of the pion-nucleus interaction is changed from the free value,b1(f;2)-1 ((qq)*)-l
R = biree =
{;
=
(qq)

(3)

Recently, the isoscalar and isovector potential parameters of the free 7r N scattering have been precisely determined as 6 ,7) b~ee = (1.7 ± 1.0) x 10- 3, andbiree = -(90.0 ± 1.6) x 10- 3 in units of m;l. The wellknown in-medium corrections on the potential parameters arising from double 7rN scattering are

bgff = b~ee - <I [( b~ee)2 + 2 (b\,ee)2] ( ~ )(4)Physik Department E12, Technische Universitat Miinchen,
GermanyF= b~ee - E1 [(b~ee)2 + 2(biree)2] 3k
47[
rv-2.08 bi.

(5)

(6)
ff

The above free 7rN parameters yield bO rv -0.017 andb1 rv -0.09. These effective values correspond to a
repulsive strength of V(O) rv 16 MeV for 205Pb, andare regarded as giving a starting point, the deviation
beyond which might be ascribed to a QeD effect.
The binding energies (Bnl) and widths (r nl) of the
deeply bound Is states of 7[- in heavy nuclei are related
nearly uniquely to V(O) and W(O) (irrespectively of the
non-local parameters) as
V(O) = -455 [b o + N ~ Z bl ] ,(7)

W(O) = -192 ImBo MeV.

(8)

An experimentally determined V(O) (in MeV) value
thus yields a straight line in the bo- b1 plane.
We take three typical cases: 7[- _205Pb, 115Sn and
123Sn. The first one has already been observed, and a
new value of V(O) rv 26 MeV has been obtained fromthe Is 7r- state in 205Pb. 3) Experiments on the Sn
isotopes will be performed in the near future.
It is clear that the experimental value, V(O)
26 MeV, for 205Pb deviates significantly from the "effective free" value. If we assert that only the isovector
part be primarily renormalized by a QeD effect, it
will cause an additional isoscalar repulsion according
to Eq. (6). Then, the experimental value V(O) yields
b1 rv -0.13,

bo rv -0.032,(9)which could indicate that (qq) is reduced by a factorof rv 0.7 in the nuclear medium.
An experimental confirmation of the above assertion
requires an additional constraint from another nucleus,
which has a <5 = (N - Z) / A value different from the firstone. The case of 123Sn (<5 = 0.187) is nearly identicalto the case of 205Pb (<5 = 0.200), but the case of 115S n(<5 = 0 .130) is very different.
A more direct determination of b1 is, of course, tocompare between the binding energies of different isotopes which have a large enough difference in <5 =(N - Z)/A. Let us take the case of 115Sn (<5 = 0.130)
and 123Sn (<5 = 0.187). Starting from the empiricalvalue V(O) = 26 MeV for 205Pb, we obtain theoreticalestimates of B 1s (115S n ) and B 1s (123S n ) as a functionof b1 , as presented in Fig. 1. A measurement of the isotope shift in Sn will thus yield a direct determinationof b1 (and subsequently, of bo).

41

References

3.91) H. Toki and T. Yamazaki: Phys. Lett. B 213, 129(1988); H. Toki, S. Hirenzaki, R. S. Hayano, and T.
Yamazaki: Nucl. Phys. A 501 , 653 (1989).
2) T. Yamazaki et al.: Z. Phys. A 355 , 219 (1996); T.
Yamazaki et al.: Phys. Lett. B 418, 246 (1998); H. Gilg
et al.: Phys. Rev. C 62 , 025201 (2000); K. Itahashi etal.: Phys. Rev. C 62 , 025202 (2000).
3) H. Geissel et al.: to be published.
4) Y. Tomozawa: Nuovo Cimento A 46, 707 (1966); S.
Weinberg: Phys. Rev. Lett. 17, 616 (1966).
5) M. Gell-Mann, R. J. Oakes, and B. Renner: Phys. Rev.
175, 2195 (1968).
6) L. Simon: Phys. Lett. B 469, 25 (1999).
7) T. E. O. Ericson, B. Loiseau, and A. W. Thomas: Nucl.
Phys. A 663/664, 541c (2000).

:> 3.65
Q)

~
(j)

3.6

CD 3.75
3.7
0.2:> 0.15Q)~(j),.....

CD 0.1
<l
0.05
-0.2

-0.05

o

Fig. 1. Calculated Is 1[ - binding energies and isotope shifts
versus b1 for the cases of 115Sn_123Sn.

42

RIKEN Accel. Prog. Rep. 34 (2001)

p-w Mixing in the Oscillation Model
H. Tezuka*[Charge symmetry breaking, Isospin mixing]
The Coulomb displacement energies of mirror nuclei, the disagreement between the proton-protonand neutron-neutron scattering lengths without any
Coulomb effects and the difference in proton and neutron analyzing powers seem to suggest charge symmetry breaking in the nucleon-nucleon interaction. 1)
One explanation of charge symmetry breaking is due toisospin mixing in p and w mesons. We showed in a previous paper that the time development of eigenstates
makes isospin mixing because of their mass difference
and that the p-w mixing oscillation causes charge symmetry breaking in the nucleon-nucleon interaction.2)
We investigated the effects of breaking with assumingthat p and w mesons created by strong interaction areisospin eigenstates.
We here reanalyzed from the stand point that theobserved p and w mesons are mass eigenstates. The
original isospin mixing Lagrangian density is given by.c = ijj{ ''''/''(i8p, - gwwp, - gpT3Pp,) - M}'ljJ
1- _F(w)
F(w)p,1/ + _1 m 2 w wP,
4 p,1/
2 w p,- ~F(p)F(p)p,1/ + ~m2p pp, + EW pp,
4 p,1/
2 p p,
p,'
Here, p and ware isospin eigenstates. To eliminate
the isospin mixing term (E wp,pP,) we introduce mass
eigenstate vector mesons, Ap, and B p,:

Ap, = wp,cosO + pp,sinO
andpion-decay, B(A ---+ 271") = 0.0221 ± 0.003, the mixing
angle (0) should be 2.25° ± 0.19°. This mixing angle
gives the p meson's three-pion-decay branching ratio,
0.00011 ± 0.00002.
Vector mesons p and w, created by strong interactions, are isospin eigenstates, but time developmentof eigenstates mixes the isospin components. The wmeson state at time t after creation is given by

w(t) = (e-imAtcos20 + e-imBtsin20)w(0)+ (e - imAt _ e-imBt)sinOcosOp(O),and the p state at t isp(t) = (e-imAtsin20 + e-imBtcos20)p(0)+ (e- imAt _ e-imBt)cosOsinOw(O),where w(O) and p(O) are the pure isospin 0 and 1 component, respectively.
The w state and the p state at time t are not isospin
eigenstates, but linear combinations of two isospin
eigenstates, w(O) and p(O) . The existing probabilitiesof the isospin 0 component and the 1 component oscillate with time. Thus, the vector mesons propagating
between nucleons are not isospin eigenstates and themixing ratios of the isospins are calculated with themixing angle (0). The pro babili t ies of the isospin 1(p) component and the isospin 0 (w) component in thephysical w state at time t are given byP(w I p) = l(e- imAt - e- imBt ) sinO cosO I2=

Bp, = -wp,sinO + pp,cosO.
The relation between the mixing coupling constant (E)and the mixing angle (0) is given bytan20 =andP(w I w) = le-imAtcos20 + e-imBtsin2012

2E

=

2
2'
mw-mp

We identify Ap, and B p, with the observed wand pmesons, which are given in the Particle Physics Booklet(PPB).3) Masses mw and mp are given by those of themass eigenstates mA and mB in PPB :m~ = m~cos20 + m1sin 20

andm~ = m~sin20 + m1cos 20.

~{1 - cos(mA - mB)t} sin 220

1-~{1 - cos(mA - mB)t} sin220.

It is shown that the above 0 reproduces a disagreement between the scattering lengths. This mixing
angle corresponds to the mixing coupling constant,
E = (0.001207 ± 0.000102)mpmw.

References
1) G . A. Miller, B. M. K . Nefkens, and L. Slaus: Phys.
Rep . 194, 1 (1990).
2) S. 9gushi, M. Terasawa, and H. Tezuka: Phys. Rev. C
56 , 2382 (1997).
3) Particle Data Group: Eur. Phys. J. C 15, 1 (2000).

To reproduce the branching ratio of w meson's twoNatural Science Laboratory, Toyo University

43

RIKEN Accel. Prog. Rep. 34 (2001)

Deconfinement by an Infinite Potential
H. Tezuka*[Confinement, Dirac equation, Vector potential]
Linear-type potentials and harmonic oscillator-type
potentials are often used as confinement potentials ofquarks in hadrons both relativistically and nonrelativistically. It has been shown that a relativistic particle described by the Dirac equation with linear potentials or harmonic-oscillator potentials cannot be confined if the potential is a vector. 1 ,2) We also showedthat both a monomial vector potential, like ar n , and apolynomial one, like ~ anr n , cannot confine a particlenin their potentials. 3 )This time we investigated the confinement problem
of a vector potential with more general forms. We
discussed the possibility of bound states in an infinitely
strong attractive vector potential.
The Dirac equation of a particle with mass m in avector potential V (r) is given by{a· p + (3m + V(r)} ~( r) = E~(r).
The vector potential is assumed to have only the 0th component and to be spherically symmetric. We
consider an infinite potential, such as V(r) ~ ±oo atr ~ 00. The vector potential with lim V (r) = +00 is
r~oocalled attractive, because V(r) increases energy withr, while the lim V(r) = -00 type vector potential isr~oorepulsive.
Rewriting the 4-spinor ~(r) asl (n)'L.Glj(r)- - 'Pjm
H~( r) =(r
Flj(r) U· ~ r./ (0)
r
r Jm

)

,

for

j = l ± ~.

2

Because we assume that V (r) becomes infinite as rincreases, it is clear that the main part at large r in
the second term of the right-hand-side is - V (r) 2 . If
V(r) ~ +00 at r ~ 00, d~~r) > 0, and if V(r) ~ -00
at r ~ 00, d~~r) < O. Thus d~~r) / V(r) is always
positive at large r. We examine whether there is aV(r) which satisfiesdV(r)~~) > V(r)2.
The left-hand-side is the largest part at large r of thefirst and third terms of the Dirac equation. After integration we obtain1- 2V(r)2 > r + const.
No solution of V(r) can satisfy the equation at r ~ 00.
We can thus concludedV(r)V~~) «V(r)2,
at r ~ 00. Therefore, at large r the main part of theright-hand-side of the Dirac equation is - V(r)2 for an
infinite potential. This term is repulsive independentof the sign of the vector potential (V(r)). Because theasymptotic equation is given by

the Dirac equation for the upper component (G lj (r))
is given bydV(r)the asymptotic wave function oscillates at large randdoes not converge. Having no bound states means thatthe infinitely strong potential does not confine a particle. A particle moving in the vector potential is notconfined and exists even at r ~ 00.
References

where

Natural Science Laboratory, Toyo University

441) Y. Shibata and H. Tezuka: Z. Phys. C 62, 533 (1994).
2) L. Tomio and P. L. Ferreira: Nuovo Ciment B 107, 785(1992).
3) H. Tezuka: Z. Phys. C 65, 101 (1995).

RI KEN Accel. Prog. Rep. 34 (2001)

Measurement of Ortho-Para Effect in Muon-Catalyzed dd-F'usion
A. Toyoda,*l K. Ishida, K. Shimomura,*2 Y. Matsuda, W. Higemoto ,*2 S. N. Nakamura,*3 T. Matsuzaki ,and K. N agamine[Ortho-para effect, Muon-catalyzed fusion]
In this report, we provide the final results of a seriesof experiments about the ortho-para effect in muoncatalyzed fusion (J.LCF) in solid deuterium (see also aprevious report 1) ) .
One of the most important subjects in a J.LCF study
is to enhance the muon cycling rate, which may beachieved by influencing the muonic molecular formation process. For this purpose, we used deuteriumby artificially changing the ratio between ortho deuterium (coupled nuclear spin I = 0, 2, rotational stateJ = even) and para deuterium (I = 1, J = odd)
(ortho-para ratio) for the first time. The ortho-para effect in J.LCF was first pointed out by Leon and Cohen 2)
and was recently calculated in detail by Faifman. 3) Inthese references, about a 10% enhancement of the fusion rate in 100% ortho deuterium at around 30 K is
predicted.
The second motivation is to understand the unexpected contradiction between the experiments 4 ,5) andtheories in the solid region (below 18.7 K). In some
explanations for the contradiction, 6, 7) the para deuterium is predicted to play an essential role. Thus, anortho-para experiment would be possible to determine
which explanation is more reasonable.
The experimental setup developed at the RIKENRAL t Muon Facility consisted of a cryostat to cool
down the deuterium target, a target chamber, twopairs of silicon surface b(Lrrier (SSB) detectors for fusion proton detection, a Si (Li) detector to cover anenergy region of 1. 5 ke V to 80 ke V for X-ray measurement, a pair of plastic scintillators to detect J.L-e decay electrons, an ortho-para converter, an ortho-para
analyzer to observe the ortho-para ratio of the converted deuterium, and a PC-based Exp 96 data-taking
system. 8 )The experiments were carried out at port 3 of the
RIKEN-RAL Muon Facility at ISIS. We fitted themeasured fusion proton time spectrum with two exponential functions (fast component and slow component), and obtained the fusion proton yield normalized
by the muon stopping number, which was estimated byusing the J.Le-decay electrons from the deuterium target. The fast component is expected to be more likely
affected by the ortho-para effect. The background wasestimated by using the target-out data.
For a comparison between the experimental result
*1
*2

*3

University of Tokyo
High Energy Accelerator Research Organization
Tohoku University
Rutherford Appleton Laboratory, UK

<1.l

ec

0.2

.g

§
..8

0
-0.2

.!'l

'0"

-0.4

g -0.6
~

~

'i3

-0.8

<1.l

>

-1

0)
0::

·1.2

c;;

Experiment(Th is work)

Theory I(Faifman.
Fi lchenkov)"non-thermaliz3[ion' ,mechanism

Theory 2(Gurin et al.
Adamczak)" heating effect"
Theory 3(Menshikov
and Filchenkov)
phonon effectFig. 1. Comparison between the theories and the experiment about the ortho-para effect.

and theories with solid effects about an ortho-para.
effect, we mtroducet he paramet er R p = yortho/pynormal_1
whereyorthoisthefusionprotonyieldp,pwith the fast component in the 99.9% ortho case andynormal is that in the normal (66.7% ortho) case.
p There have been theoretical proposals for solid effects in J.LCF:· tIOn' " mech'9)
theory 1, "non-t h erma1lza
amsm;
theory 2, muonic atom "heating effect" ;7)
theory 3, phonon effect .6 )Figure 1 shows a comparison of Rp between theories and this experiment. From this figure, two of the
proposed solid effects, namely, a muonic atom "heating
effect" and a phonon creation effect, which are strongly
dependent on the ortho-para ratio (in other words, therotational-state ratio) of deuterium molecules, are understood to be negligibly small. Our result favors the"non-thermalization" effect without a large contribution of dJ.L atom acceleration.
References
1) A. Toyoda et al.: RIKEN Accel. Prog. Rep. 33 , 49
(2000).
2) M. Leon and J. S. Cohen: Phys. Rev. A 31,2680 (1985).
3) M. P. Faifman: private communication.
4) D. L. Demin et al.: Hyperfine Interact. 101/102, 13(1996).
5) P. E. Knowles et al.: Hyperfine Interact. 101/102, 21(1996) .
6) L. I. Menshikov et al.: Hyperfine Interact. 101/102,
207 (1996).
7) G. L. Gurin et al.: Hyperfine Interact. 118, 147 (1999).
8) S. N. Nakamura and M. Iwasaki: Nucl. Instr. Meth. in
Phys. Res. A 388, 220 (1997).
9) V. V. Filchenkov: Hyperfine Interact. 101/102, 37(1996) .

45

RIKEN Accel. Prog. Rep. 34 (2001)

Temperature-Dependence of Muon Catalyzed Fusion
in Solid Deuterium and Tritium Mixtures
N. Kawamura, K. Nagamine, T. Matsuzaki, K. Ishida, S.N. Nakamura,*l Y. Matsuda, M. Tanase,*2
M. Kato,*2 K. Kurosawa,*2 H. Sugai,*2 K. Kudo,*3 N. Takeda,*3 and C.H. Eaton*4[Muon catalyzed fusion]
Since the first observation of an unexpected density dependence of the muon cycling rate (Ac) by
Jones et ai.,l) its origin has been one of the main
subjects in p,CF studies, both theoretically2,3) andexperimentally.4,5) A precursory idea proposed by
Vesman 6 ) succeeded to explain that Ac was above 108
S-l by hypothesizing a resonant dtp, formation mechanism in a collision between tp, and D2 or DT. This theory predicted Ac to be constant with respect to the target density. Moreover, a theoretical calculation basedon Vesman's mechanism 7) predicted for Ac to decrease
steeply with decreasing temperature below 100 K; also,
Ac at 20 K was expected to be one order of magnitude
smaller than that at 100 K. However, these theoretical predictions are inconsistent with the experimental
results,4,5) which are summarized as follows:I

1

x : C t = O.2

120

o : C t = O.3
o : C t =O.4-------+------.-+ : C t =O .5):( : C t =O.6
oJ< : C t =O.7

tlIl

.S

U
>,

80

()

>::
0

60

;j

:::g

10

15

20

Temperature at sensor [K]Fig. 1. Temperature dependence of the muon cycling rate ,>"c, in the cases of the tritium concentration, Ct, from
20% to 70% .

• Density dependence: the muon cycling rate increases with increasing density.
• Temperature dependence: the muon cycling rate
does not decrease with decreasing temperature below lOOK.
These discrepancies may be due to incomplete
knowledge of dtp, formation.
Some ideas were proposed to revise Vesman's mechanism, e.g. quasi-resonance in a three-body collision 2)
and the phonon effect,3) although they are not definitive. In the experimental studies up to the present, themain concentration has been put on the density dependence. However, in order to investigate the dtp, formation mechanism, an approach from a different aspect,
i. e. the temperature dependence, can provide new information.
In the present work, we conducted a series of p,CF
experiments in solid deuterium and tritium mixtureswith various tritium concentrations (Ct ) from 20% to70%, and at temperatures from 5 K to 16 K. All of
the experiments were carried out at the RIKEN-RAL
Muon Facility by observing fusion neutrons and X-rays
associated with the muon-to-a sticking phenomenon.
A preliminary analysis was performed. Figure 1 shows
the temperature dependence of the muon cycling rate(Ac), which is mainly determined by the fusion-neutron
*1
*2
*3
*4

46

Present address: Tohoku University
Japan Atomic Energy Research Institute (JAERI)
Electrotechnical Laboratory (ETL)
Rutherford-Appleton Laboratory (RAL), UK

data. As can be clearly seen in this figure, Ac decreased
with decreasing temperature in every Ct case.
Experimentally, we can determine Ac , and not the
dtp, formation rate (AdtJ,l.)' Ac consists of many parameters, including AdtJ1.' Although it is the most acceptable interpretation that the observed change in Ac
is caused by a change in AdtJ,l. ' other parameters may
cause the change in Ac. In order to determine eachparameter independently, a further analysis was performed for the C t dependence of Ac at 5 K and 16 K by
the method described in the article. 5) Although there
still exists some ambiguity, the abovementioned interpretation has been confirmed to be correct. Namely,
the observed change in Ac is explained by the change
in AdtJ,l.'

AdtJ,l. : 340 p,S-l (16 K) ~ 200 p,S-l (5 K).
A theoretical understanding of this result is an urgent subject for the near future.
References
1)
2)
3)
4)
5)

S. E. Jones et al.: Phys. Rev. Lett. 56, 588 (1986).
L. I. Menshikov et al.: Phys. Lett. B 167, 141 (1986).
K. Fukushima: Phys. Rev. A 48 , 4130 (1993).
P. Ackerbauer et al.: Nucl. Phys. A 652, 311 (1999).
K. Ishida et al.: submitted to Phys. Rev. Lett.; Hyperfine Interact. 118, 203 (1999).
6) E. A. Vesman: Zh. Eksp. Teor. Fiz. Pisma 5, 50 (1967)(Sov. Phys. JETP Lett. 5 , 91 (1967)).
7) M. P. Faifman et al.: Phys. Lett. B 265 , 201 (1991).

RIKEN Accel. Prog. Rep. 34 (2001)

Neutron Energy Spectrum from Muon Catalyzed t-t Fusion
in a Solid T2 Target
T. Matsuzaki, K. Ishida, N. Kawamura, S. N. Nakamura,*1 Y. Matsuda'3 K. Nagamine, M. ~ato , *2
K. Kurosawa,*2 H. Sugai,*2 M. Tanase,*2 K. Kudo,*3 N. Takeda,* and G. H. Eaton*[Muon catalyzed t-t fusion]
We have conducted an experiment on muon catalyzed t-t fusion in a solid T2 target by detecting Xrays and neutrons. This experiment is important not
only for obtaining supplementary data for the muon
catalyzed d-t fusion data analysis , but also for a studyof the muon catalyzed t-t fusion mechanism.
The muon catalyzed t-t fusion reaction is expressedast + t + p, - t 4He + n + n + p,- + Q (11.33 MeV) (1)(p,-4He) + n + n.

(2)

We performed an experiment at Port 1 using thesame experimental set-up as that for d-t p,CF studies. I )The T2 target gas was purchased from the Chalk River
National Laboratory in Canada and installed to an insitu tritium gas handling system. 2) The isotopic enrichment of Twas 99.1% with the major remaining
components of H (0.67%) and D (0.07%). The 3He impurity originating from tritium ,B-decay was removed
in the tritium gas-handling system. The T2 gas wasthen introduced to a target cell cooled by a heliumflow cryostat and solidified at 15 K.3) The solid T2 target with a volume of 0.6 cm 3 was formed from the T2
gas: a volume of 0.574 liter at STP and a radioactivityof 55.2 TBq (1492 Ci). In order to detect the t-t fusion
neutrons, two calibrated NE213 liquid scintillators (2inch in diameter and 2 inch in length) were positioned
at a distance of 84 cm downstream of the target. 4) A
decay p,- beam with a momentum of 54.5 MeV /c wasinjected to the T2 target and about 70p,- were stopped
every muon pulse with a double-pulse time-structure.
The observed recoil proton energy spectrum is shownin Fig. 1 (a). The neutron energy distributes continuously up to 9 MeV, being superimposed on the background from the d-t fusion neutrons whose maximum
energy is 14.1 MeV. Even if the impurity concentrationof the D component in the target T2 gas is 0.07% , thed-t p,CF cycling rate is two orders of magnitude larger
than the one for t-t p,CF and the contribution by thed-t I1CF is not negligible. However, the energy distribution of the d-t fusion neutron was well-determined
and we could subtract the contribution from the raw
spectrum. The obtained spectrum after subtraction isshown in Fig. 1 (b). The spectrum indicates that a
*1
*2
*3
*4

Tohoku University
Japan Atomic Energy Research Institute (JAERI)
Electrotechnical Laboratory (ETL)
Rutherford Appleton Laboratory (RAL), UK:::::: 10

2

.~

0..

c.r 10~~1........

·1

>10
Q)

~

0

2

4

6

2

4

6

8

10

t.r)

........
10r/J.......

s= 10
:s
0

U

1

8

12

14

16

Neutron energy [MeV]Fig. 1. A recoil proton energy spectrum observed for thefusion neutrons from the t-t ,uCF process. (a) The raw
spectrum. (b) The spectrum after subtraction of thed-t fusion neutron contribution.

large portion of the reaction Q-value is carried away
by one neutron in the t-t p,CF exit channel. Thisphenomenon is very interesting, and can be well understood by a picture in which the first neutron behaves in strong correlation with a 4He nucleus, like in
an intermediate 5He nucleus formation, and the second neutron takes out a large amount of energy withthe maximum possible energy (9.4 MeV) being 5/6 of
the Q-value. The PSI group has reported a measured
neutron energy distribution from t-t p,CF,5) but theirspectrum drops at the maximum energy of 5 MeV, inconsistent with our observed maximum energy. So far,no theoretical work has been published on the fusion
neutron energy distribution from the t-t p,CF process.
Gershtein et al. have calculated the energy distribution of (p,4He) atoms produced in reaction (2) under
three assumptions of the statistical distribution, then-n correlation and the n- 4He correlation. 6 ) The predicted spectrum gives a distribution of the subtraction
between the reaction Q-value and the t-t fusion neutron energy distribution in reaction (2). The prediction
with the assumption of an n- 4He correlation supports
the present observed neutron energy distribution.

47

References
1) K. Ishida, K. Nagamine, and T. Matsuzaki et al.: Hyperfine Interact. 118, 203 (1999).
2) T. Matsuzaki, K. Nagamine, and M. Tanase et al.: Hyperfine Interact. 119, 361 (1999).
3) K. Ishida, T. Matsuzaki, and K. Nagamine: RIKENRAL Annual Report 17 (1997).

484) N. Kawamura et al.: to be submitted to Nucl. Instrum.
Methods Phys. Res. A.
5) W. H. Breunlich et al.: Muon Catal. Fusion 1 , 121(1987).
6) S. S. Gershtein et al.: SOy. Phys. JETP 53 , 872 (1981).

RIKEN Accel. Prog. Rep. 34 (2001)

Electron-Nucleus Collider at MUSES
T. Suda, K. Maruyama,* and 1. Tanihata[e+RI collider, Elastic scattering, High resolution spectrometer]
A collider of electrons and a radioactive-ion beam,
an e+RI collider, planned in the MUSES project aims
at investigating the nuclear structure of many RIs byelectron scattering. The charge distributions of unstable nuclei is a main subject to be determined by elastic
electron scattering.
We have previously reported the results of our study
to clarify the requirements for an electron spectrometer. To achieve an energy-transfer resolution (.6..w) toa target nucleus of 1 MeV in the N ucleus-Rest (NR)frame, the required momentum and angular resolutions in the COLlider (COL) frame were found to be
10- 3 and 1 mrad, respectively, for an optimum electronenergy of Ee = 500- 700 Me V. We proposed a large
acceptance spectrometer (LAS), which tracks electron
trajectories in a solenoidal or troidal magnetic field bytracking devices. The LAS covers an azimuthal angle of nearly 27r, which seems to compensate the low
luminosity expected in the e+RI collider.
To measure the elastic-scattering cross section ofheavier nuclei, however, .6..wNR = 0.1 MeV instead of.6..w N R = 1 Me V will be indispensable. In this case, themomentum resolution, .6..p/p, in the COL frame must
be better than 10- 4 , which forces us to give up LAS
and to employ a high-resolution spectrometer (HRS).
Obviously, a price to pay for keeping a good .6..p/p isa smaller solid angle. We have been working to study
the feasibility of employing HRS for the e+ RI collider.
By a careful consideration of the electron-scattering
kinematics, the drawback has been found to be overcome by setting the HRS at a very forward angle. At a
forward angle, the cross section increases rapidly, andone also gains a larger coverage for the azimuthal angle. For instance, HRS having a ±100-mrad verticalangular acceptance covers more than 20% of 27r at ascattering angle of 5 degrees .
Due to low luminosity, it is not possible to determine the charge form factor up to the high momentum
transfer (qNR) region in the NR frame. Dependingon the maximum qNR, up to which the form factor ismeasured, the charge distribution, Pc(r), or the meansquare charge radius , < r~ >1/2, of an unstable nucleus
will be determined. When the form factor is measured
up to at least the first diffraction maximum, one candetermine Pc (r). In the case for very unstable nuclei,
whose luminosity is so low that the form factor can bemeasured only in lower qN R than that for the first dip,
< r~ > 1/2 is determined.

...CD

80

.c 60
E

Sn

~

Z

c: 40

....00... 20Q.

oo 20 40 60 80 100 120 140
Neutron Number

Fig. 1. Accessible form-factor region for each nuclei in aone-week measurement under the given luminosity.

Figure 1 shows the results of a simulation to estimate
the accessible form-factor region, as shown by a gradation of gray colors, for each element by a one-weekmeasurement. The simulation uses the luminosity table of the MUSES e+ RI collider. A scattering angleof 5-25 degrees is assumed to be covered by a pairof high-resolution spectrometers, whose horizontal andvertical angular acceptances are both ±100 mrad.
As an example, let us briefly discuss the proton
magic Sn isotope, which is one of key nuclei for thee+RI collider. The minimum luminosity needed to determine < r~ >1/2 and pc(r) is 1022 and 10 26/cm 2 /s,
respectively. Since the luminosity for a double-magic
nucleus 13 2 Sn is expected to be 6 x 10 22 , we will beable to determine < r~ >1/2, as can be seen in Fig. 1.
Because the luminosity is expected to be larger than
10 26/cm 2 /s for 108- 128 Sn , these isotopes are candidates
for a Pc(r) determination.
In summary, it is shown that a forward-angle highresolution spectrometer can be a solution for the
MUSES e+ RI collider to determine < r~ > 1/2 andpc(r) of many isotopes. The solid angle of the spectrometer needs to be 40 msr or more, and the momentum and angular resolution must be better than
10- 4 and 1 mrad. Since the design of the spectrometer strongly depends on the lattice structure of the collider , discussions are now underway with the MUSES
accelerator group.

Kitasato University

49

RIKEN Accel. Prog. Rep. 34 (2001)

Measurement of the Cross Sections and Analyzing Powers
for d-p Elastic Scattering at Intermediate Energies
K. Sekiguchi,*l H. Sakai,*l N. Sakamoto, H. Okamura,*2 A. Tamii,*l T. Uesaka, *2
Y. Satou, T. Ohnishi, T. Wakasa,*3 K. Yako,*l S. Sakoda,*l K. Suda,*2
H. Kato,*l Y. Maeda,* l M. Hatano,*l and J . Nishikawa*2
NUCLEAR REACTIONS, 1 H(J: d), Ed = 140,200,270 MeV measured: 0'(8), Ay(8), A yy (8),][ A xx(8), A xA8)
The three nucleon force (3NF) effects in a
nucleon-deuteron (N d) system at intermediate energies (E / A ;::: 60 Me V) are attracting current interest.
This is partly because rigorous numerical calculations
are available in terms of Faddeev theory using modern N N forces together with 3NF. Therefore it is becoming possible to compare the calculated results withaccurate experimental ones.
In order to study the 3NF effects systematically, we
made precise measurements of the cross section and all
deu teron analyzing powers (Ay, Ayy, A xx and Axz ) for
d-p elastic scattering at Ed = 140, 200 and 270 MeV,
covering a wide angular range of 8c .m . = 10 0 - 180 0 • Apart of the data has been published in Refs. 1 and 2.
The CH 2 target was bombarded by polarized deuteronbeams. Either scattered deuterons or protons weredetected by the magnetic spectrograph SMART, depending on the scattering angle. The beam polarizations were monitored by using a beam-line polarimeterbased on d-p elastic scattering, and their magnitudes
were 60- 80% of the theoretical maximum values during the experiments. The statistical errors are within
1.3% for cross sections and ±0.02 or less for Ay, ±0.01
or less for Ayy , ±0.02 or less for A xx and ±0.03 or lessfor A xz, respectively. The uncertainty of the target
thickness and charge collection of the beam were also
estimated by comparing the measured cross sections
for p-p elastic scattering with the calculated values by
SAID.3) The ratio of the observed cross sections to thecalculated ones is 1.010 ± 0.013 for the measurement
at 270 MeV. Thus, the systematic error is estimatedto be less than 2%.
In Fig. 1 the experimental results of the cross section
and the tensor analyzing power Ayy are shown by open
circles. Theoretical predictions are also shown. 2,4) The
solid curves are calculations with Tucson-Melbourne
3NF5) and the dashed ones are those which consider
only N N forces. The CD BONN potential6 ) is usedas N N interaction in these calculations. For the crosssection, there is a discrepancy in the cross section minimum between the data and the calculated results without 3NF. This discrepancy can be removed by adding
3NF. For Ayy , the difference between the data and
*1

*2

*3

50

School of Science, University of Tokyo
Department of Physics , Saitama University
Research Center for Nuclear Physics, Osaka University

Ayy
0.8

102

'"i:'
IZl
'-....

..c

10 1

~
c

"t:l
'-....
b

"t:l

100

60

100

(J c.m.

[deg]

160

60

(J c.m .

100

160

[deg]

Fig. 1. Cross sections and the tensor analyzing power Ayy
for d-p elastic scattering at 140, 200 and 270 Me V. The
dashed curves are the Faddeev calculations in which
the CD BONN potential is used as the N N interaction.
The solid curves are the Faddeev calculations including
the TUcson-Melbourne 3NF.

the calculations without 3NF becomes clearer as theenergy increases, while this difference is not describedby taking 3NF into account. The agreement is deteriorated when 3NF is included. This feature indicatesthat the difference in the cross section minimum could
be considered as a signature of 3NF, although this 3NF
model might have some deficiencies in the spin dependent part.
References
1) N. Sakamoto, H. Okamura, and T . Uesaka et al.: Phys.
Lett . B 361, 60 (1996).
2) H. Sakai, K . Sekiguchi, and H. Witala et al.: Phys. Rev.
Lett. 84, 5288 (2000).
3) R. A. Arndt and L. D. Roper: S cattering Analysis Interactive Dial-In program (SAID) , Virginia Polytechnic
Institute and State University (unpublished).
4) H. Witala and H. Kamada: private communications.
5) S. A. Coon et al.: Nucl. Phys. A 311, 242 (1997) .
6) R. Machleidt, F. Sammarruca, and Y. Song: Phys. Rev.
C 53 , R1483 (1996).

RIKEN Accel. Prog. Rep. 34 (2001)

Measurement of the Polarization Correlation Coefficient for the3Ife( d, p )4He Reaction
J. Nishikawa,*1 T. Uesaka,*1 A. Tamii,*2 N. Sakamoto, Y. Satou, T. Wakui, T. Ohnishi,
K. Sekiguchi,*2 K. Suda,*1 S. Sakoda, *2 S. Yamamoto,*3 H. Kato,*2 M. Hatano,*2
T. Saito,*2 N. Uchigashima,*2 H. Okamura,*1 and H. Sakai*2[3H~(d~p)4He reaction, Ed = 140, 200, and 270 MeV, Polarization correlation coefficient]
The deuteron D-state wave function is one of thetools used to study the short-range behavior of tensor components in the nucleon-nucleon (N-N) interaction. We are investigating the deuteron D-state by
the polarization correlation coefficient (C/ /) for the
3H~(J:p)4He reaction. 1) C/ / is proportional to the Dstate density of the deuteron wave function within
the framework of the one-nucleon exchange approximation. This C/ /, which is defined as the ratio of thespin-parallel cross section (0') to spin-unpolarized crosssection (0'0), is given by
C/ /(0°) ==

:0

=

*1
*3

....,CIl

600

~

;:::l

o

U

400

200

1 + ~Ayy(OO) + ~Cy,y(OO).

We have measured Cy ,y(OO) at the RIKEN Accelerator Research Facility (RARF) to obtain C/ /(0°), combining it with the tensor analyzing power (Ayy(OO)) ,which was measured before. 2)
A polarized deuteron beam was accelerated to Ed =140, 200, and 270 MeV by the AVF Cyclotron and theRing Cyclotron. The beam polarization was measured
with a polarimeter located at the beam delivery room.
The polarized beam was transported to the spectrograph SMART. A polarized 3He target, which wasplaced in a chamber at the exit of the first dipole
magnet (PDl), was bombarded by a polarized beam.
Two quadrupole magnets (PQl and PQ2) and PDl
were used for beam tuning. 3He gas of 10 20 cm- 3
in density enclosed in a glass cell was polarized by
the spin-exchange method. 3) The length of the cellwas 100 mm and the thickness of the entrance andthe exit window was 0.1 mm. The typical polarization of 3He was approximately 13%. Scattered protons were analyzed by subsequent quadrupole (PQ3)and dipole (PD2) magnets and detected by a multiwire drift chamber and plastic scintillators placed ina focal plane. The deuteron beam and the low-energy
deuterons were stopped by a beam stopper placed in
PD2 and in front of the focal plane.
The proton events were selected by using the timeof flight (TOF) from the target to the detector andthe energy loss in the plastic scintillators. The proton energy spectrum is shown in Fig. 1. The peak at
Ex = 0 MeV is due to the 3H~(d~p)4He reaction and*2800

Department of Physics, Saitama University
Department of Physics, University of Tokyo
Department of Physics, Toho University- 2 .5

2.5

0 .0

Ex

[MeV]

Fig. 1. Excitation energy spectrum for the 3H~(d~ p)4He
reaction at Ed = 200 Me V. The FWHM of the peak at
E x = OMeV is approximately 180keV.

0 .5

;:.

;;.

0 .0

C,.)

- 0 .5

0 .0

0 .2

0.4

0 .6

k pn [GeV/ c]

Fig. 2. Cy ,y for the 3H~( ct: p )4He reaction at Ed = 140,
200, and 270 MeV , (left, center and right points) respectively. The solid line is a calculated result with the
one-nucleon exchange approximation.

is missing in the empty-cell spectrum. The FWHM of
the peak is approximately 180 keY.
Cy ,y was deduced by using spin-dependent cross sections obtained for all possible combinations of thebeam (Py = 0, +~ , -~) and target polarization (upand down). Preliminary results of Cy,y are shown in
Fig. 2 as a function of the momentum between the proton and the neutron in the deuteron center-of-mass sys-

51

tern, kpn . The solid line represents a calculated resultwith the one-nucleon exchange approximation. Data
can be reproduced by the calculation quite well. A
detailed analysis is in progress.
References
1) T. Uesaka et al.: Phys. Lett. B 467, 199 (1999).

522) T. Uesaka et al.: RIKEN Accel. Prog. 33, 55 (2000).
3) S. Yamamoto et al.: RIKEN Accel. Prog. 34, 198(2001).

RIKEN Accel. Prog. Rep. 34 (2001)

Measurement of the 12C(d, d') Reaction at 270 MeV and a
DWIA Analysis Using the Three-Body dN Interaction
Y. Satou, H. Sakai,*l H. Okamura,*2 N. Sakamoto, T. Uesaka,*2 A. Tamii,*l K. Itoh, T. Ohnishi,
K. Sekiguchi,*l K. Yakou,*l s. Sakoda,*l K. Suda,*2 M. Hatano,*lH. Kato,*l Y. Maeda,*1 J. Nishikawa,*2 and H. Kamada*3[Nuclear reaction, Three-body dN interaction]
Light-ion-induced inelastic scattering at bombarding
energies above 100 MeV per nucleon has been an appealing probe of nuclear-structure studies because thedistorted wave impulse approximation (DWIA) is applicable for reaction calculations. In the IA for the(p, p') reaction, the effective interaction is taken to
be the free nucleon-nucleon t-matrix, which can be
regarded as being known. In the case of the (d, d')reaction, however, the situation is more complicated,because the structure of the deuteron must be considered. Today, three-nucleon (3N) Faddeev calculations
make it possible to described the deuteron-nucleon(dN) scattering processes, even at intermediate energies with a reliable accuracy. 1) Therefore, the use of theFaddeev dN t-matrix as an effective interaction could
provide a precise DWIA description of the (d, d') reaction. Here, we report on data for the differential
cross section for low-lying states in 12C excited via the(d, d') reaction at 270 MeV and compare them with
DWIA calculations.
The measurement was performed using the 270 MeV
deuteron beam from the Ring Cyclotron by bombarding a 31.3 mg/cm 2 12C target. The scattereddeuterons were analyzed with the magnetic spectrometer SMART. The cross sections for the 2+,3-, 1+ and
2- states are shown in Fig. 1 (a). The angular distributions are characteristic of the definite transferredangular momentum (~L).
Microscopic DWIA calculations were made by following the description in Ref. 2. The T-matrix is given
by
DWIA
T dA

= (X( -) (R)Xdl<P A* (i1) ItdNeiq·(P-R) IX( +) (R)Xd<P A (i1)),

where the distorted waves in the initial and final chahnels are denoted by X (+) (R) and X (- ) (R), the target
wave functions by <P A (i1) and <P A * (i1), and the deuteronspinors by Xd and Xd ' , respectively. if is the transferred momentum. The on-shell dN t-matrix (tdN)
obtained by 3N Faddeev calculations, was used as aneffective projectile-nucleon interaction. The distorted
waves were generated with the optical potential fitted
to elastic-scattering data (see Fig. 1 (b)).
.1

.2
•3

University of Tokyo
Saitama University
Ruhr University, Germany

10 2

12 C(d,d')

10 1

103

E~=270 MeV,,-... 10 1

100

M

I:
102
C/l

rn
.........
.DE-.........
,Q

E- 10 1

100

c:

C
"d

"0

.........
b"0.........

100

100

10- 1

10- 1

10

20

e cm (deg)

b
"d

100

10- 1
10

20

e cm (deg)

10

20

30

ecm (deg)

Fig. 1. (a) Measured differential cross sections for the
12C(d, d') reaction at 270 MeV leading to low-lying
states in 12C (full circles) compared with DWIA calculations (solid lines). (b) Measured differential crosssection for the elastic scattering of a deuteron from 12C
at 270 Me V. The solid line is the result of an opticalmodel fit.

The results of DWIA calculations are compared withthe data in Fig. 1 (a). The angular-distribution shapes
are well reproduced by the calculations. For the 2+
and 3- states, a normalization factor of about 2 foundin electron scattering3) was not needed, in agreementwith the (p, p') results at incident energies of 100200 MeV. 4 ,5) In this energy range the magnitude of
the theoretical (p, p') cross section for the 1+ state is
known to depend sensitively on the choice of the effective interaction. 4- 6 ) The present calculation well reproduces the data without introducing any normalization
for this state, in agreement with the (p, p') analysis
in Ref. 6. The cross section for the 2- state slightly
underestimates in the calculation. The good overall
agreement between the data and the calculations indicates that the dN t-matrix obtained from the 3N Faddeev calculations gives a sound basis for the projectilenucleon effective interaction in the DWIA descriptionof the (d, d') reaction at 270 MeV. A striking resemblance between the results of the (d, d') and (p, p') reactions suggests that the former reaction is as sensitive
as the latter to the microscopic structure of the target.
This is encouraging for a nuclear structure study considering the additional selectivity of the (d, d') reaction
to the isoscalar ~T = 0 transitions .

53

References
1) W. Glockle et al.: Phys. Rep . 214, 107 (1996).
2) J. Van de Wiele et al.: Phys. Rev. C 50, 2935 (1994).
3) J. B. Flanz et al.: Phys. Rev. Lett. 41, 1642 (1978).

544) J . R. Comfort et al.: Phys. Rev. C 24, 1834 (1981).
5) J. R. Comfort et al.: Phys. Rev. C 26 , 1800 (1982).
6) A. Willis et al.: Phys. Rev. C 43 , 2177 (1991).

RI KEN Accel. Prog. Rep. 34 (2001)

Study of Neutron-Rich Nuclides Relevant to
the Astrophysics R-Process
Y. Nishi, S. Nishimura, 1. Tanihata, K. Morimoto, R. N. Boyd,* and M. Famiano*[R-process, N ucleosynthesis, ,6-decay half-life]
The requirements of the r-process (rapid-process) ofstellar nucleosynthesis have been well known for several decades. 1) It must produce all nuclei heavier than
209Bi as well as the r-process abundance peaks. And it
must do so in a way that does not depend on the preexisting seed nuclei. Several features of the nuclei along
the r-processes path are important for abundance predictions. The mass differences between nearby nuclei
determine their stability to the (,' n) process in the hot
photon bath in which they are immersed during the rprocess. Their lifetimes determine the abundances, if
they are at neutron closed shells, of the stable nuclei
to which they ultimately decay. Finally, their decay
modes, via e-, e-n, or something more complex, could
produce shifts of the r-process peaks.
At first, we are planning and preparing a ,6-decay
half-life measurement. Clearly, the measurement time
for nuclei closer to the neutron drip line will be long,
because of the low production rate. We are thus developing 5-layer rotation stopper disks, along with 2dimensional position-sensitive ,6-ray detectors and ,ray detectors, in order to measure many different nuclei concurrently as well as many events within one
stopper foil. Figure 1 shows a schematic view of therotation stopper disks and detectors which we are developing. Each stopper disk has 11 foils. As shown in
Fig. 1, a neutron-rich nuclei beam will be implanted
to the foil of a certain disk at # 1, depending on therange of the nuclide. The stopper disks will be rotated
5/11 x 27r [rad] within 300msec. , after which irradiatedfoils will come to #6 where fixed position-sensitive detectors are located. While the decays of the nuclei inthat foil are being measured, another foil will be irradiated.
The detectors consist of a fine plastic-scintilator array and NaI scintilators. Each plastic scintilator has a
4 x 64 mm 2 effective region and 1 mm or 2 mm thickness . The elements are read out by a 16 ch multi-anode
PMT (H6568-10 HAMAMATSU co.). These 16 plastic
scintilators are combined into one plate (64 x 64mm 2),
and two plates are placed perpendicularly. Hence, twodimensional information concerning the ,6-rays can beobtained, making it possible to identify the implanted
nucleus which we want to detect and to separate thatfrom the backgrounds using position information. N aI
scintilators having a 4 cm thickness are placed between
the plastic scintilator plates in order to do gamma-ray
spectroscopy. Rotation stoppers have already beenFig. 1. Schematic view of the rotation stoppers and detectors.

10

.,
·2

10
10

-3

10 .. L...r..-----.h<---..h-----,J,,----J;~.-lFig. 2. Cross section of the U-FIF measured at GSI and
the expected cross section of the PF estimated by EPAX(ver.2) calculation, where 136Xe is used as the primarybeam and Ta as a target.

constructed and confirmed to work well. The designof the detectors has been completed and they are under construction. In early 2001 , the first experiment isscheduled using a 64Ni beam, followed by a heavy mass
region experiment, executed using 104Ru and 136Xebeams, and so on.
In order to achieve a higher production cross sectionof neutron-rich nuclei along the r-process path whichis extremely low, we hope to measure and compare theproduction cross section of the neutron-rich nuclei using Projectile Fragment (PF) for 136Xe and 104Ru, andfission in flight for 238U (U-FIF), if possible. Figure 2
shows the cross section of the U-FIF measured at GSI
together with the expected cross section of the PF estimated by the latest EPAX (ver.2) calculation, where
136Xe is used as the primary beam and Ta as a target .
It shows that the cross section of U-FIF seems to belarger than that of PF. However , there are parameters which must be taken into account for a realistic
scenario, i. e. the beam intensity, target thickness, andthe acceptance of the RIPS. Especially, it is necessary
to investigate the advantage of the U-FIF method forthe case of neutron-rich nuclei.
References
1) G. Wallerstein et al.: Rev. Mod. Phys. 69 , 945 (1997).

Ohio State University, USA

55

RIKEN Accel. Prog. Rep. 34 (2001)

Study of the Secondary Fusion Reaction with
the High-Spin Isomer Beam
H. Watanabe, T. Kishida, Y. Gono,*l T. Morikawa,* l S. Motomura,*l T. Fukuchi,*l O. Kashiyama,*lK. Saitoh,*l A. Odahara,*2 T. Kubo, E. Ideguchi,*3 B. Cederwall,*3 T. Back,*3
D. Bucurescu, *4 and M. Ishihara
NUCLEAR REACTIONS 160(l36Xe,7n)145mSm, 13C(l45msm, xn)158-XEr, High-spin iso-j[mer beam
A high-spin isomer beam (HSIB)l) has been developed at the RIKEN Accelerator Research Facility(RARF). The most remarkable feature of the HSIB
compared with a ground-state beam (GSB) is the large
intrinsic 'nuclear spin. Such high-spin isomers havebeen observed systematically in N = 83 isotones with
proton number Z from 60 to 68. In recent studies,
145mSm (Z = 62) , which has a nuclear spin of I = ~,has been mainly used for a secondary reaction. The
145m Sm beam was produced via an inverse-kinematic
fusion reaction, 160(l36Xe,7n)145Sm, which led tothe beam energy of 5.53 ± 0.11 MeV/nucleon. The
experimental technique to obtain the 145mSm beam
intensity of 1- 2 x 105 pps on a secondary target wasestablished with the development of a windowless gas
target 2) and a superconducting solenoid. By using
this beam, the secondary fusion reaction has been
investigated. When the fusion reaction is inducedby the HSIB , the angular momentum distribution in
the compound nucleus is expected to extend towarda higher region due to the vector sum of the isomer
spin and the orbital angular momentum brought into
the system. Then, the compound nucleus increases
in excitation energy only by that of an isomericstate (c::: 9 Me V) in addition to that carried in by aprojectile. Therefore, it may be possible to produce
the compound nucleus in a lower energy-higher spinstate, namely near to the yrast line. In the present
work, the 13Ce 45m Sm, xn) 158- X Er reaction wasstudied. The ,),-rays which were emitted from thesecondary fusion products 154Er could be identified
for the first time in spite of numerous contamination,),-rays in the spectra. The most probable spectrum
is shown in Fig. 1, where the ,),-rays of 154Er aremarked with arrows and energy values reported
previously. The yields of ')'-rays of interest were ingood agreement with the estimated value within theexperimental accuracy. However, the amount of angular momenta brought into the system by the HSIB
could not be compared with those by the GSB experimentally because of the poor statistics and the large
*1

*2

*3
*4

56

Department of Physics, Kyushu University
Nishinippon Institute of Technology
Department of Physics, Royal Institute of Technology, Sweden
National Institute for Physics and Nuclear Engineering, Rumania

backgrounds. Information concerning the spin distribution formed by the GSB has been already deduced
from appropriate experimental probes, i. e. the yrast

100

455.6

80

ir; (j()

i~

«)

20
0
-20
~

600

6SO

700

&SO
900
Energy [keV)

950

1000

SSO

500

Energy (keV)
SO

805.0

«)

1• 30

j

20

10
0
-10
-20
700

750

SOO

Fig. 1. Background subtracted spectra from the sum ofgated spectra in the yrast band of 154Er. The energies
of ,-rays in the yrast band are marked with arrows.

Fig. 2. Averaged angular momenta obtained in the GSB
experiment (square) and calculated for the GSB (cross)and the HSIB (plus) as a function of the bombarding
energy [MeV/nucleon] for 154Er.

,,-ray flow and the ,,-ray multiplicity. These quantities were compared with those resulting from a simulation performed by the code CASCADE. The averageangular momenta deduced from the ,,-ray multiplicity
are shown in Fig. 2. As can be seen, the measured,,-ray multiplicity reflects the amount of angular momentum brought into the system. These results encouraged us to measure the ,,-ray multiplicity in the

HSIB experiment so as to investigate the difference inthe transfered angular momenta between the HSIB and
the GSB.
References
1) Y. Gono et al.: Nucl. Phys. A 588 , 241c (1995).
2) T. Kishida et al.: Nucl. lnstrum. Methods Phys. Res. A
438, 70 (1990).

57

RIKEN Accel. P rog. Rep. 34 (2001)

Excitation-Energy Dependence of the GDR in Hot 209Bi Nuclei
Y. Aoki, * K. Yoshida, T. Nakagawa, K. Nakagawa, and J. Kasagi*
NUCLEAR REACTION, 209Bi+ 2o9 Bi EI A = 12 MeV lu; Inelastic scattering; Measured high][energy, rays, protons, and residues; Deduced CDR response
The excitation-energy dependence of the propertyof the giant dipole resonance (CDR) in 209Bi on the
excitation energies up to 500 MeV was studied by measuring the high-energy , rays in coincidence with theheavy fragment. There have been many studies concerning the CDR of hot nuclei in the Sn region. However, the experimental data are scarce for heavier nuclei.
The excited states of 209Bi were populated bydeep inelastic scattering of 209Bi + 209Bi at
12 MeV Inucleon. A beam of 209Bi from the RIKEN
RINC Cyclotron irradiated a 1 mg/cm 2 209Bi selfsupport target. Fragments of the reaction were detected by 3 large PPAC lIonization chambers. Protons
evaporated from the fragments were measured by acrystal ball consisting of 65 BaF 2 poswitch detectors.
The excitation energy of each fragment was determinedby the kinematics of the detected fragment, and wasconfirmed by the energy spectra of the protons.
The high-energy ,-rays were measured by 2 sets ofhigh-energy , -ray detectors consisting of 7 BaF 2 scintillators. The ,-ray spectra were obtained for thefour excitation bins of 0- 40, 40- 100, 100- 250 , and 2::
250 MeV. The multiplicities of the, rays were alsomeasured by a crystal ball and used for deducing theangular momenta of the excited fragments.
The obtained spectra were compared with statisticalmodel calculations using the code CASCADE. In thecalculation, the initial distribution of the excitation energies and the angular momenta of the fragments weretaken from the experimental data. The CDR energies(Ec) and widths (f c) were treated as the parameter
and were determined by a X 2 fitting of the calculated
spectra and experimental spectra. The CDR strength
was fixed at the value of the full energy-weighted sum
rule. We made two different assumptions concerning
f c. One was that f c is fixed during the de-exciting
cascade. This assumption is commonly used for the
CDR analysis. The apparent width (f app) is obtainedin this assumption, since we neglect the change of f calong with the decay. The other was that f c varies
according to the excitation energies of the de-exciting
state, so that the variation of f c is properly includedin the calculation. Both calculations gave a similar
quality of the fits.
In Fig. 1, the obtained f c is plotted against thetemperature (T) of the initial state. Temperatures
were obtained from the excitation energies by correctLNS, Tohoku University

58'""' 30

><ll

6
25

20

~o 15

10

5

00

0.5

1.5

2

2.5
T

3

3.5

4

4.5
5
(MeV)

Fig. 1. Temperature dependence of the GDR width of
209Bi. The circles are the results from the fixed-r G calculation. The solid line shows the width deduced fromthe variable-r G calculation. The gray zone along withthe line indicates the uncertainty of r G. The theoretical results from Ormand et al. l ) and Dang et al. 2 ) arealso shown as dashed and dotted lines, respectively.

ing the effect of the angular momenta. f app, which was
obtained based on the former assumption, are shownas circles in the figure. As can be seen , the apparent
widths are varied from 4.8 Me V to 12 Me V along withan increase in the temperature from to 2.5 MeV andsaturate for higher temperatures. Although the result
agrees well with the theoretical work of Ormand etai.1) and Dang et ai.,2) the assumption is not justified,since fc is varied from 4.8 MeV to 12 MeV. The resultof the latter assumption, which includes the effect ofthe varied width, is shown as the solid line of Fig. 1.
f c is a similar value to f app for T ::; 2 MeV, but a
rapid increase of fc is seen for T 2:: 2.5 MeV. This
result is in disagreement with the theories, althoughsimilar results were experimentally obtained in the Sn
region.3 )The rapid increase of fc indicates that CDR disappeared due to successive broadening of the width. We
defined the limiting temperature of the CDR as thetemperature at which fc exceeds 30 MeV, and is plotted in Fig. 2 against the mass together with the resultsof other experiments. 3 ) As can be seen, the limiting°

;;- 5Q)

622

5 X 10-temperature of the CDR is well-scaled by the lifetimesof the excited states , which are estimated from the statistical model. It can be said that the CDR disappears
at a lifetime of about 8 x 10- 22 sec.

S

4.5

References
1) W. E. Ormand, P. F . Bortignon, and R. A. Broglia:
Phys. Rev. Lett. 22 , 607 (1994).
2) N. Dinh Dang and A. Arima: Nucl. Phys. A 636 , 427(1998) .
3) J. Kasagi , et al.: Nucl. Phys. A 538, 585c (1992) .

4

3.5

-e
E-<:'::
3

2.5

2

o J.Kasagi et aI. , NucI.Phys_A538(\992)585c• _this work

1. 5 l..L.c2---'---5--'----'----'-'5---'---0--'----'-''-'7---'-5----'----'----'-')---'0-'---0 -'--'----')---'---2-'-5-'--'----')---'5-'-0--- -'--'----').J.-'-5-'---'---'2.J.---'-'--'-'2.J.-'-5-'--'--'--'
250
7
2
OO
A

Fig. 2. Limiting temperature of the GDR are plotted as afunction of mass A. The temperatures of the excitedstates corresponding to their lifetimes of 1 x 10- 22 and5 x 10- 23 are also shown in the figure.

59

RIKEN Accel. Prog. Rep. 34 (2001)

Search for a Z == 118 Superheavy Nucleus
in the Reaction of 86Kr with 208Pb
K. Morimoto, K. Morita, 1. Tanihata, N. Iwasa,*1 R. Kanungo, T. Kato, K. Katori, H. Kudo,*2
T. Suda, 1. Sugai,*3 S. Takeuchi, F. Tokanai,*4 Y. Wakasaya,*5 T. Yamaguchi,
A. Yeremin, *6 A. Yoneda, A. Yoshida, and M. Giurgiu[NUCLEAR REACTION, Gas-filled recoil separator, Alpha-decays]
Last year, three decay chains were reported by aLawrence Berkeley Laboratory groupl) in the reaction
products of 86Kr with 208Pb. The observed chains havea possibility to be consistent with the formation of
293 118 and its sequential a decays. However, the decay
chains are not associated with any known nuclei. The
observed production cross section is 2.2 (+2.6, -0.8)
pb. This experiment was motivated by a following recent prediction of Smolanczuk,2) which indicates thatthe cross section of a cold-fusion reaction of 86Kr with
208Pb is 670 pb. Although the experimental cross section reported is by 3 hundred times smaller than thatof the theoretical prediction, we made a followup experiment of the LBL group, because it is still muchbigger than the cross section systematics with extrapolation of the experimental values.
The experimental set up is shown in Fig. 1. The
Pb target thickness was 320- 440 p,g/cm 2; it was evaporated onto the downstream side of a 100 p,g/cm 2 carbon foil. Furthermore, the target was covered by 2030 j.1g/cm 2 carbon with evaporation. Six segments of
it were mounted on a wheel that rotated at 600 rpm.
The beam energy was 457.6 MeV, and the beam current was 500 particle nanoamperes on the average. The
incident beam energy at the center of the target was
449 MeV. To avoid the primary beam from impinging
on the silicon detector in the event of a broken target,!Stripperfoill

I RIKEN GARIS (Gas-tilled Recoil Separator) I

Fig. 1. Schematic view of the experimental set up.
*1

*2
*3
*4
*5

*6

60

Tohoku University
Niigata University
Institute for Particle and Nuclear Studies, High-Energy Accelerator Research Organization (KEK)Yamagata University
IBM Corporation
Flerov Laboratory of Nuclear Reactions JINR, Russia

a carbon foil of 30 p,g/ cm 2 thickness was mounted as acharge stripper of primary beams. The reaction products recoiling out of the target were separated fromthe primary beam by using a gas-filled recoil separator, GARIS.3) The separator was filled with heliumgas at one torr. After passing through the separator,
the recoiling particles were implanted in a positionsensitive silicon detector (PSD), which had an active
area of 60 x 60 mm with a thickness of 300 j.1m. Lightcharged particles passing through the PSD were detected by a veto SSD. The total counting rate of the
PSD was several counts/sec under the condition with
1000 particle nanoamperes of the beam intensity. The
dead time of electronics was reduced by using a double
trigger system, which was able to accumulate two 'implanted or decay' events as a one 'electronics' event.
It was 20 p,s for less than 2 events and 800 p,s for morethan 3 events. The total system was checked by thereaction of 86Kr with lloCd.
We had machine times in Feb. 2000. The first 4
days were performed for a test of targets, an estimation of the magnetic rigidity (Bp), calibrations of thedetectors and a check of the data-acquisition system.
The last 10 days were used to accumulate a dose of
2 x 10 18 ions, but no candidate of the evaporation
residue was found. In this beam dose, when we assume that the efficiency of GARIS was 0.8 and that
one event was observed, the cross section corresponds
to 0.6 pb. Since we used a gas-filled separator withhelium gas as the LBL group did, a problem of chargechanging decay of isometric states in flight would beless significant than the production experiment with avacuum-type kinematic separator as SHIP at GSI or
as LISE at GANIL. We chose the value of the magnetic rigidity of the separator to be 2.1 Tm in orderto make the experimental condition as close as that of
the LBL group. However, this Bp value still has an
ambiguity as a suitable value for 293 118. Because themean values of the charge states in the helium gas forsuch atoms its atomic number larger than 110 have notbeen well studied experimentally, we should perform asystematic study of them.
References1} V. Ninov et al.: Phys. Rev. Lett. 83, 1104 (1999).
2} R. Smolanczuk: Phys. Rev. C 59, 2634 (1999).
3) K. Morita et al.: Nucl. lnstrum. Methods Phys. Res. B
70, 220 (1992).

RIKEN Accel. Prog. Rep. 34 (2001)

Super heavy Hydrogen 5H, Spectroscopy of 7He
A. A. Korsheninnikov, M. S. Golovkov , A. Ozawa, K. Yoshida, 1. Tanihata, Z. Fulop, K. Kusaka, K. Morimoto,
H. Otsu, H. Petrascu, F. Tokanai, D. D. Bogdanov,*1 M. L. Chelnokov,*1 A. S. Fomichev,*1 V. A. Gorshkov *1
Y. T. Oganessian,*1 A. M. Rodin,*1 S. I. Sidorchuk,*1 S. V. Stepantsov,*1 G. M. Ter-Akopian,*1'
R. Wolski,*1 W. Mittig,*2 P. Roussel-Chomaz,*2 H. Savajols,*2 E. A. Kuzmin,*3
E. Y. Nikolskii,*3 B. G. Novatskii,*3 and A. A. Ogloblin*3

Both neutron-rich nuclei 5H and 7He were investigated in numerous experiments for 30 years. However,until now, the existence of 5H as a well-defined resonance was remained unclear. The ground state of 7He,
which decays into n+ 6He, was established very wellexperimentally, but many attempts to observe an excited state of 7He were unsuccessful. We performed aspectroscopic study of 5H and 7He using radioactive
beams.
To search for 5H, we applied an experimental
method that is similar to the missing-mass method,
but with the detection of unstable recoil particles. In
the usual missing-mass experiment, a binary reaction,A(b, c)D, is studied, and a measurement of the recoil
particle, c, allows one to obtain an excitation spectrum
for the residual nucleus, D. If the residual system, D,is very neutron rich, then - generally speaking - theparticle c is very proton rich and it can even be unstable, like, e.g. , 6Be, that decays into p+p+a, or thesimilar singlet-state 2He, that decays into p+p. To
deal with an unstable recoil nucleus, c, one needs todetect all particles from its decay. Having kinematically complete information on the unstable system c
one can determine the excitation energy in the resid~ai
system, D, and perform its spectroscopy.
For the spectroscopy of 5H we studied the reactionp(6He,2He)5H. The secondary beam of 6He with theenergy of 36A MeV was obtained using the fragment
separator ACCULINA at JINR (Dubna). As a target we used a cryogenic target from GANIL (France),
which was filled with hydrogen gas. Two protons fromthe decay of 2He were detected in coincidence by the
RIKEN telescope, which represents a stack of ring-likesolid-state strip-detectors. Apart from protons, we also
detected tritons from the decay of 5H---+t+n+n, using
a downstream telescope consisting of a large-area SSDdetector and a BGO-crystal.
Figure 1 shows the preliminary result for the 5H
spectrum extracted from the p+p-coincidences andmeasured in coincidence with tritons from the decay of
a 5H-system, p(6He,ppt). The spectrum is shown as afunction of the energy of 5H above the decay threshold,
t+n+n. The background from measurements with an* 1 · JINR, Russia
*2
*3

60

>

50

0)

..101:

8

~

!!l

40

30

c::

= 20

0

u

10

o -4

-2

0

2

4

6

8

10

E ,MeV
5H

Fig. 1. Missing mass spectrum of 5H from the reactionp(6He,ppt).

empty target (instead of the target filled by hydrogen)was negligible in this spectrum. A cut-off at rv 7 MeV
reflects the detection limit due to the acceptance of the
RIKEN telescope.
In the spectrum of Fig. 1, a peak at rv 2 Me V attracts attention, which is a good candidate for the resonance 5H. An analysis of the data is still in progress.
Note that the spectra obtained for different reaction
channels (p(6He,pt)3H and p(6He,t)4He) show proper
peaks corresponding to the residual nuclei eH and
4He) , which implies the reliability of the obtained results.
To search for excited states of 7He, we performed
two experiments. In the first experiment we used asecondary beam of 8He produced by the fragment separator RIPS. We studied the reaction p(8He,d)1He
and observed an excited state of 7He which decays into
4He+3n. Most likely, this state has a structure witha neutron in the excited Pl/2-state coupled to the 6He
core, which, itself, is in the excited 2+ state. These
results were recently published. 1)
In the second experiment, we especially aimed
at searching for single-particle states in 7He. Thed(6He,p) reaction was investigated using the 6He secondary beam produced by the fragment separator ACCULINA at JINR (Dubna). We used the GANIL cryogenic target , which was filled with deuterium. An analysis of the obtained data is in progress.
References
1) A. A. Korsheninnikov et al.: Phys. Rev. Lett . 82, 3581
(1999).

GANIL, France
Kurchatov Institute, Russia

61

RIKEN Accel. Prog. Rep. 34 (2001)

Observation of an Excited State In 7He with an Unusual Structure t
A. A. Korsheninnikov, M. S. Golovkov, A. Ozawa, E. A. Kuzmin,*l E. Y. Nikolskii,*l K. Yoshida,
B. G. Novatskii,*l A. A. Ogloblin,*l 1. Tanihata, Z. Fulop, K. Kusaka,
K. Morimoto, H. Otsu, H. Petrascu, and F. Tokanai[NUCLEAR REACTION, p(BHe,d)7He, E = 50AMeV, Nuclear structure]
To perform the spectroscopy of 7He, we studied
the reaction p(BHe,d)7He. A secondary beam of BHe
at 50A MeV was produced by the fragment separator
RIPS. As a proton target, we used CH 2 . Backgroundmeasurements with a carbon foil and an empty target were also performed. Deuterons were detected bya telescope of ring-like strip-detectors at small angles
in a laboratory system corresponding to a high crosssection. In addition to the deuterons, we detected particles emitted from the decay of 7He. Neutrons were
measured by the neutron walls of plastic scintillators,
while charged particles were bent in a dipole magnet
and detected by a drift chamber and the plastic scintillators' hodoscope. These parts of the detection system allowed us to investigate the spectra of deuterons
detected in coincidence with 6He, 4He, and neutrons.
As a result, we obtained the deuteron spectra fromthe reactions p(BHe,d), p(BHe,d 6He), p(BHe,d 4He),
p(8He,dn), p(BHe,dn6He), and p(BHe,dn4He).
The obtained spectra show the well- known groundstate of 7He at the energy En - 6He = 0.44 MeV above
the decay threshold, n+ 6He, but also an excited stateof 7He at En - 6He
3.3 MeV. The decay scheme of
7He is shown in Fig. 1.
The most interesting experimental finding is thatthe revealed excited state of 7He decays predominantly
into 4He+3n, in spite of a larger 6He+n decay energy.
f".J

*1

62

Condensed from the article in Phys. Rev. Lett. 82, 3581
(1999)
Kurchatov Institute, Russia'He
3.3±0.3 MeV///////".r""

f,...,2.2MeV

1.80 MeV~ev

n+6He*(2+)
0.44 MeV
f=0.16 MeVoFig. 1. Decay scheme of 7He.

This reflects an unusual structure of this state.
The structure of the found 7He* level should represent a neutron in an excited state coupled to the
6He-core, which itself is in the excited 2+ -state. The
population of such an unusual state in our experimentis consistent with the structure of BHe used as a projectile, because the ground state of BHe contains mainly
the 6He-subsystem in the excited 2+ -state.

RIKEN Accel. Prog. Rep. 34 (2001)

Search for Neutron Pair Pre-Emission in the Fusion of llLi Halo
Nuclei with Si Target
M. Petrascu,*l 1. Tanihata, K. Morimoto, T. Kobayashi,*2 K. Katori, 1. Cruceru,*l M. Giurgiu, A. Isbasescu,*lH. Petrascu,*l R. RUSCU,*l M. Chiba,*2 S. Nishimura, A. Ozawa, T. Suda, K. Yoshida, and C. Bordeanu*3[comcldences

N~C~EAR REACTIONS; Si(l1 Li, fusion), Erv13 A MeV; Secondary beams;

The pre-emission of neutrons in the fusion of 11 Li
halo nuclei with Si targets was first reported in Refs. 13. The pre-emission of neutron pairs was first analysed in Ref. 4. However, the statistics of n-n coincidences was rather low due to the fact that the detection system was unsuited for such measurements.
Reported here are the results of a recent experiment
performed by the aid of a new array4) detector, built
within the cooperation between IPNE-Romania and
RIKEN-Japan. The diagram of the experimental setup is similar to the previous one, except for the facts
that an array detector was used instead of the RIKEN"Long neutron wall" and a Si detector-target 500 11m
thick was placed in the MUSIC chamber instead of theprevious 250 11m thick Si detector target. The array detector consists of 81 elements, made of 4 x 4 x 12 cm 3
BC-400 crystals, mounted on XP2972 phototubes. The
efficiency of the crystals 4) based on a Monte Carlo calculation for 13 MeV neutrons is 34%. The array detector was placed at a distance of 138 cm from the target.
A calibration to determine the thresholds of those detectors was performed by means of cosmic rays. The
measurements were performed with 13 A Me V 11 Li and9Li beams. The 9Li beam, which had no pre-emissionsof neutron pairs, was used for a cross-talk background
determination. It was found that the cross-talk coefficient for adj acent detectors (first-order coincidences)
is 0.020 ± 0.003, for detectors separated by one detector (second-order coincidences) is 0.0052 ± 0.001, andfor detectors separated by two detectors (third-ordercoincidences) is 0.0017 ± 0.0007
The processing of data obtained with 11 Li revealed
a remarkable n-n coincidence effect. After subtracting
the cross-talk background, 109 ± 23 first-order n-n coincidences, 107 ± 15 second-order n-n coincidences and98.7 ± 12.4 third-order coinCidences remained within
the range of the narrow neutron group (the neutrons
distribute in a narrow forward angle).
On the basis of the n-n coincidence results, a concentration of (84 ± 8)% neutron pairs within a narrow

Neutron]240

Data: Oata3_B
Model: Gause
CtiA2 86.59131
yO
69.4021-0.33402w
10.79071
A
1894.77629

220

=

200

en 180

:t:!

c

::J

.e

:1:6.72025
t!J.32777
t!J.97321:1:215.9787

160
140

~
' ) 120:[ 100
Z
'0
80
60
40
·20

·15

·10

·5

o

5

10

15

20

Transverse Momentum ~x(MeV/c)

Fig. 1. Transverse momentum distribution of the preemitted neutrons in the fusion reaction of 11 Li + Si
measured along the line parallel to the x-axis. Froma Gaussian analysis, it follows that the width of the
distribution is (10.7 ± 0.97) MeV Ie.

neutron group was estimated. From the obtained coincidence results, the differential cross-section as a function of the angle () (LS) between the momenta of two
neutrons was also derived. For most of the neutron
pairs, () (LS) is less than about 3°.
The measurement with the array detector allowed
a new, very precise determination of the transverse
momentum distribution for the neutrons within the
narrow group. It turns out that the FWHM of this
distribution is close to 11 MeV/c.
Figure 1 shows the results concerning the determination of transverse momentum of narrow neutron group.
References
1)
2)
3)
4)

M. Petrascu et al.: RIKEN AF-NP-237 (1996).
M. Petrascu et al.: Phys. Lett. B 405, 224 (1997).
M. Petrascu et al.: Rom. J. Phys. 43, 307 (1998).
M. Petrascu et al.: Rom. J. Phys. 44, 83 (1999).

National Institute of Physics and Nuclear Engineering, Romania*2 Tohoku University*3 . Weizman Institute, Israel*1

63

RIKEN Accel. Prog. Rep. 34 (2001)

Sub-Barrier Fusion of 11 Be+ 209 Bi
C. Signorini, A. Yoshida, T. Fukuda, Y. Watanabe, Y. Mizoi, N. Fukuda, H. Sakurai, Y. Watanabe,
D. Pierroutsakou, L. Stroe, P. K. Saha, and M. Ishihara[NUCLEAR REACTION: 9,10,11 Be+ 209 Bi, Sub-barrier fusion , a-decay]
Measurements of the sub-barrier fusion cross section in the system of 11 Be (halo nucleus) + 209Bi andthe comparisons with the 9Be (stable nucleus) + 209Bi
one have been extensively studied in paralle1. 1,2) The
main goal is to investigate whether effects from thehalo structure and/or the weak binding energy of thelast halo neutron show up in the cross sections. The
results up to now show that the fusion cross sectionsin the above barrier region are reduced by ",30% forboth 11 Be and 9Be due to the neutron breakup competing process. This may be due to the small binding
energy of the last neutron, Sn = 0.5 MeV for 11 Be and1. 7 MeV for 9Be. In the sub-barrier region, those two
fusion cross sections are quite similar. This is rather
unexpected and needs to be confirmed by more accurate measurements , since the fusion cross section forthis 11 Be system consists of the 5n, 4n, and fission
channel, but the 3n long-lived channel contribution
could not be included. Our experimental setup was
improved to measure the 3n evaporation residue, 217Fr(EO! = 8.32 MeV, T1 / 2 = 16 j.Ls).
9,10,11 Be beams were produced by the fragmentation process of a 13C primary beam with 100 A MeV
energy and around 100 pnA intensity on a Be production target with 12 mm thickness. Those Be isotopes
were separated by the RIPS projectile fragment separator, resulting in a purity of almost 100%. The
typical beam intensity of these isotopes was 150 kcps
with an energy of E cm = 47MeV ± 15% (in fwhm)
on the Bi target. In order to improve the statistics of fusion events, a stack of 3 thin Bi target foils(800 j.Lg/cm 2 evaporated on 70 j.Lg/cm2 Mylar foil) was
surrounded by 16 large Si surface barrier detectors(SSD) with a size of 48 x 48 mm 2 and a thickness of
300 j.Lm. The detection solid angle for the a-decays
from one target was around 80% of 4 7r. A plastic
scintillator counter with a thickness of 1 mm was introduced at the end of the target stack in order toeliminate any non-reaction events where the beam penetrates until the end without fusion. The multi-hit

64

50
~

'M

40

.0

~ 30

~

L.()

N

. . . . 20
CIl
+J
~

g 10
u

o

7000

8000

9000

10000

Ealpha [keV]
Fig. 1. The a-decay spectra from 21 5 Fr and 216Fr.

TDC was introduced in order to record all the timing within 20 j.Lsec long ADC gate period. Using thesemethods we can select delayed a-decay events from3n) 217 Fr and also select the fission events with the coincidence of beam timing and 2 plane hit of SSD detectors. Figure 1 shows a part of the observed a-decay
spectra from the fusion evaporation residue nucleus5n) 215 Fr (EO! = 9.35 MeV, T1 / 2 = 86 ns) and 4n) 216 Fr(EO! = 9.0 MeV, T 1/ 2 = 700 ns) with the decay timing
analysis gate < 2 j.Lsec. We gained the total statisticsof these a-decay events by around two-times the previous one. A timing analysis of the TDC is proceeding inorder to reduce the background at the 3n) 217 Fr peak,which is mainly from an elastic scattering of the otherbeam particle, accidentally coinciding during the long
ADC gate period.
References '1) C. Signorini et al.: Eur. Phys. J. A 2 , 227 (1998).
2) C. Signorini et al.: Eur. Phys. J. A 5 , 7 (1999).

RI KEN Accel. Prog. Rep. 34 (2001)

Inelastic Alpha-Scattering R eactions on 14 0 and 12Be
A. Saito,*l S. Shimoura,*2 T. Minemura,* l Y. U. Matsuyama,*l H. Baba, *l H. Akiyoshi, N. Aoi, *3 T. Gomi,* l
Y. Higurashi,*l K. Ieki,*l N. Imai,*3 N. Iwasa,*4 H. Iwasaki,*3 S. Kanno,*l S. Kubono,*2 M. Kunibu,*lS. Michimasa,*2 T. Motobayashi,*l T. Nakamura,*5 H. Sakurai,*3 M. Serata,*l E. Takeshita,*lS. Takeuchi,*l T. Teranishi,*2 K . Ue,*2 K. Yamada,*l and Y. Yanagisawa
NUCLEAR REACTIONS:[Inelastic Scattering

4He(140 ,14 0*), 4He(12Be,12Be*),

Inelastic alpha scattering at intermediate energies isa powerful tool for investigating the excited states ofnuclei , especially for giant monopole resonances, in order to discuss nuclear compressibility.1) We have measured the inelastic a -scattering cross section on theunstable nuclei 14 0 and 12Be in inverse kinematics forthe first time. The present experiment was aimed atmeasuring the cross sections to the known 0+ stateand other states and obtaining higher excitation energy spectra by using the invariant mass method forvarious decay channels.
Radioactive beams of 14 0 and 12Be were produced by the RIKEN Projectile-fragment Separator (RIPS) by projectile-fragmentation reactions of
135 MeV/nucleon 16 0 and 100 MeV/nucleon 18 0 ,respectively.
The energies of the beams were
59 MeV /nucleon and 60 MeV/nucleon, respectively.
The secondary beams were identified event-by-eventfrom time-of-flight (TOF) information between twoplastic scintillators of 0.5 mm thicknesses separated by
5.3 m from each other. The secondary beams bombarded a liquid helium target confined within a cellwith a window of 24 mm diameter. The direction andposition of each beam particle at the secondary target
were measured by two sets of Parallel Plate Avalanche
Counters (PPAC 's) installed upstream from the secondary target.
Outgoing particles were detected and identified by aplastic scintillator array hodoscope located 4 m downstream from the secondary target. The array consistsof three layers (tl.E , E1, and E2) of 5mm, 60mm,
60 mm thicknesses, respectively. The energies andscattered angles of the particles were determined by
the TOF's and hit positions in the hodoscope, respectively. Each particle was identified by using the TOFtl.E and TOF-E methods.
An array of sixty-eight NaI(Tl) scintillators of
6 x 6 x 12 cm 3 rectangular shape coupled to a 5 cm ¢E lab . = 60 Mev/nucleon,]

10 2 ~~~~~~~~~~~~~~~~~~o1234
E 1 [MeV]
Fig. 1. Doppler-corrected ')'-ray energy spectrum obtainedin coincidence with the reaction products of Be isotopes.

photomultiplier tube were set around the secondary
target. The segmentation of the array allowed us tocorrect for any Doppler shifts from moving reaction
products.
Figure 1 shows an on-line Doppler-shift-corrected
spectrum of 'Y rays for events identified as Be isotopes at the tl.E hodoscope in the 4He+ 12 Be reaction . De-excitation'Y rays were observed at energies of0.38 MeV , 2.10 MeV, and 3.36 MeV which correspondto the known 'Y lines from llBe*(1/2-), 12Be*(2+),2)
and 10Be* (2+) states, respectively.
Data analyses are now in progress.
References
1) D. H. Youngblood et al.: Phys. Rev. C 57, 2748 (1998) ;D. H . Youngblood et al.: Phys. Rev. C 60 , 014304(1999) .
2) H . Iwasaki et al.: Phys. Lett. B 4 8 1, 7 (2000); H.
Iwasaki et al.: Phys. Lett. B 491, 8 (2000).

* 1 Department of Physics, Rikkyo University*2 Center for Nuclear Study, University of Tokyo*3 Department of Physics , University of Tokyo*4 Faculty of Science, Tohoku University*5 Department of Applied Physics, Tokyo Institute of Technology

65

RIKEN Accel. Prog. Rep. 34 (2001)

Measurement of the Magnetic Moment for 15C
H. Ogawa,*l K. Asahi, K. Sakai,*l H. Ueno, M. Nagakura,*2 T. Suzuki,*3 H. Miyoshi,*l Y. X. Watanabe,
N. Imai,*4 K. Yoneda, A. Yoshimi, K. Yogo,*l T. Suga,*l A. Goto,*l T. Honda,*l Y. Kobayashi,
A. Yoshida, T. Kubo, and M. Ishihara
NUCLEAR STRUCTURE: Spin-polarized radioactive beams, ,8-NMR, Measured magnetic][ moment, 15Cg.s.
The magnetic moment for 15Cg.s. (111: = 1/2+,
Tl/2 = 2.449 s) has been measured by means of thefragmentation-induced nuclear polarization techniqueand ,8-detected nuclear magnetic resonance (,8-NMR)
spectroscopy. The /11: = 1/2+ ground state of 15C
in a shell model is to a large extent described by
the 14C(O+) ® V(281/2) configurations, and its magnetic moment may provide good information abount
the neutron g8 factor appropriate in a neutron-rich nucleus.
Fragments of 15C were produced in the fragmentation of 18 0 (E / A = 70 MeV) projectiles on a 9Be(184 mg/cm 2) target using RIPS. The fragment emission angle (8 L ) and momentum (PF) were selected inorder to obtain the spin polarization as 8L = 4.2 ± 2.20
and PF = 5.51 - 5.57GeV /e, respectively. Then, thepolarization, P
1.4%, was observed if a ,8-ray asymmetry factor A{3 = -0.48 was assumed. Thus, polarized 15C fragments were implanted in a highly purified graphite stopper to which a static magnetic field,
Bo = 149.35 mT, was applied. After the beam-on period, an RF field was applied perpendicular to the Bo
field with its frequency being swept over a specified region. If the Lamor frequency (lIL) was located within
the region of the frequency sweep, the fragment spins
were flipped by means of the adiabatic fast passage
method of NMR (AFP-NMR), and as a result a change
in the ,8-ray asymmetry was observed.
The NMR spectrum obtained for the measurementof the 15C magnetic moment is plotted in Fig. 1. A
tentative analysis gives the resonance frequency lIL =3916 ± 20 kHz, corresponding to a magnetic moment oflJ-Le 5C) 1= 1.720 ± 0.009J-LN (preliminary).
The present value of J-Le 5C) is fairly close to themagnetic moment of a pure 81/2 neutron configuration,~g8' For example, the single-particle magnetic moment is obtained as J-L(lI[81/2])eff = -1.746J-LN if we takethe effective M1 operator of Brown and Wildenthal. 1)
The experimental magnetic moment for 15Cg.s . IS III
good agreement with a shell-model calculation using
the OXBASH code, taking the effective M1 operators
which are commonly used in the region of stability, as
shown in Fig. 2.
t"V* 1 Tokyo Institute of Technology
*2

*3

*4

66

Sanwa Newtec Co., Ltd.
Sony LSI Design Inc.
University of Tokyo

1.245
1.240
1.235

0

.~

1.230

C

::; 1.225
1.220
1.215
1.210

JlC C .s,)54v=36.8 kHz

g

3850

3900

3950

4000

4050

V (kHz)Fig. 1. Spectrum obtained for the lSC magnetic momentmeasurement. The [3-ray up/down ratio is plotted asa function of the oscillating frequency (v) with its frequency being swept from 1/ - ~ L:ll/ to 1/ + ~ L:ll/.

1~I(n.m.)2.0

1.9'.'--- Schmidt value
1.8
PSDWBT

1.7~_mm experiment

1.6

Fig. 2. Comparison between the experimental J..LeSC)
value and a shell-model calculation using the PSDWBTinteraction 2 ,3) in which the effective M1 operator fromthe work of Arima, Shimizu, Bentz and Hyuga4 ) for
protons and that from Brown and Wildenthal 1 ) for neutrons are employed.

References
1) B. A. Brown et al.: Nucl. Phys. A 474, 290 (1987).
2) E. K. Warburton et al.: Phys. Rev. C 46, 923 (1992).
3) B. A. Brown et al.: Computer code OXBASH, MSU
Cycl. Lab. Rep., No.524 (1986).
4) A. Arima et al.: Adv. Nucl. Phys. 18, 1 (1987).

RIKEN Accel. Prog. Rep. 34 (2001)

Search for Opposite Deformations of the Proton and Neutron
Distributions in 16C
A. Krasznahorkay,*l T. Motobayashi,*2 1. Tanihata, H. Baba,*2 M. Csatl6s,*1 ZS. Dombnidi,*l N. Fukuda,
ZS. Fiilop,*1,2 Z. Gacsi,*l J. GUlyas,*l N. Iwasa,*3 H. Kinugawa,*2 S. Kubono,*2 M. Kurokawa,*4 X. Liu,*4
S. Michimasa,*4 T. Minemura,*2 A. Ozawa, A. Saito,*2 S. Shimoura,*2 S. Takeuchi, P. Thirolf,*5
Y. Yanagisawa,*4 and K. Yoshida[NUCLEAR REACTIONS: 208Pb(16C, 16 C*), 53A MeV]
Recently, Horiuchi and Kanada-En'yol,2) performed
systematic calculations for Li, Be, B, and C isotopes within the antisymmetrized molecular dynamics(AMD) model. Although the proton density of C isotopes always has an oblate deformation, the neutron
density is predicted to change its deformation fromoblate to prolate as a function of the neutron number.
We intended to measure the charge and massdeformation parameters of 16C using a Coulombnuclear interference effect in the inelastic channel populating thestate. The interference between the
Coulomb and nuclear excitation in the inelastic scattering of light and heavy ions has been studied by several groups, both experimentally and theoretically. 3,4)
The interference manifests itself as a pronounced minimum in the inelastic scattering angular distribution
at bombarding energy and scattering angle conditions
corresponding to approximately a grazing collision. In
addition, the predicted cross sections for similar andopposite deformations of proton and neutron densities
differ by about 100% around e = 3°, assuming an angular resolution of ~eCM ::; 0.2°.
The experiment was performed at RIKEN, Japan. A
18 0 primary beam of 100AMeV energy and 380pnA
intensity bombarded a 9Be target of 9.0 mm thickness. A 16C beam was separated by the RIPS fragment separator. 5) The corresponding 16C energy was
53A MeV, and no beam contamination has been observed. The momentum resolution of the separator
was set to 0.1%.
The 16C beam bombarded a 50 mg/cm 2 208Pb target
with 99.5% enrichment. The scattering angle was determined by four parallel plate avalanche counters,6)
three of them upstream, and one downstream of thetarget. Due to mainly multiple scattering in the target,
the angular resolution of the system was ~eCM ~ 0.4°.
Particle identification of the scattered particles wasmade by a plastic scintillator hodoscope, placed 5 mfrom the target. The hodoscope 7 ) consisted of 5 mm
thick ~E and 60 mm thick E plastic scintillators of
1 m length, and covered a solid angle of 5.7 degrees.

2t*1

ATOMKI, Hungary*2 Rikkyo University
*3

*4
*5

Tohoku University
Center for Nuclear Study, University of Tokyo
Ludwig-Maximilians-Universitat, Germany~ 8000§.J:: 7000~
CI)....c::::s 6000

0

U

5000
4000

3000
2000
1000
0

50

100

150

200

250

Channels
Fig. 1. Doppler shift corrected gamma spectrum collectedby the DALI array. The de-excitation of the 16C 2+state can be used to select the inelastic scattering reaction channel.

The vacuum chamber of the hodoscope, and the last
PPAC detector were separated by a thin Mylar foil.
The gamma de-excitation of the inelastic scattered 16C
particles was detected by the DALI detector array, consisting of 68 NaI crystals8) with a size of 6 x 6 x 12 cm 3.
The array was shielded by layers of 20 cm paraffin 1 mm
cadmium and 10 cm lead.
A Doppler shift corrected ')'-spectrum collected by
the DALI array can be seen in Fig. 1. The (E, =1766 ke V) transition in 16C is clearly seen in the spectrum. Further analysis, e.g. angular distribution determination of the scattered 16 C particles is in progress.
References
1) H. Horiuchi and Y. Kanada-En'yo: Nucl. Phys. A 616,
394c (1997).
2) Y. Kanada-En'yo and H. Horiuchi: Phys. Rev. C 55,
2860 (1997).
3) W. Bruckner et al.: Phys. Rev. Lett. 30, 57 (1973).
4) S. H. Fricke et al.: Nucl. Phys. A 500, 399 (1989).
5) T. Kubo et al.: Nucl. Instrum. Methods Phys. Res. B
70, 309 (1992).
6) H. Kumagai et al.: RIKEN Accel. Prog. Rep. 31, 164(1998) .
7) I. Hisanaga et al.: RIKEN Accel. Prog. Rep. 31, 162(1998) .
8) T. Motobayashi et al.: Phys. Lett. B 346, 9 (1995).

67

RIKEN Accel. Prog. Rep. 34 (2001)

Electric Quadrupole Moment of 17B
H. Miyoshi,*1 H. Ogawa,*1 K. Asahi, K. Sakai,*1 H. Ueno, T. Suzuki,*2 M. Nagakura,*3
T. Honda,*1 Y. X. Watanabe, N. Imai,*4 K. Yoneda, T. Suga,*1 A. Yoshimi, K. Yogo,*1
Y. Kobayashi, A. Yoshida, T. Kubo, W.-D. Schmidt-Ott,*s G. Neyens,*6 S. Teughels,*6 and M. Ishihara
NUCLEAR STRUCTURE, spin-polarized radioactive beams, jJ-NMR method, measured][quadrupole moment of 17B
The electric quadrupole moment (Q moment) for theneutron-rich isotope 17B (I7r = 3/2-, T1/2 = 5.08ms)
has been determined using a polarized radioactive isotope beam.
The experiment was carried out at RIPS. A 17B
beam was produced from the fragmentation of 22Ne
projectiles on a 1.07 g/cm 2 thick 93Nb target at anenergy of 110 MeV/nucleon. In order to obtain spinpolarized 17B fragments, emission angles of () =0.5-3.8° and the fragment momenta of p = 7.107.54 Ge V / c were selected. The obtained polarizationis P rv -1.0/A,6%, where A,6 denotes the jJ-asymmetry
0.97

C

-

I-~__~~I.~~I==~_
1
RFoff-0.96

0==

Cl

0.95

c..
:::>

0.94

i
I
i
i

!i

I
i
i
i

0.93
0.92 L -_ _

!

~

__ i

~

__

~

_ _ _ _ _----'

0.98 ~--...,...---+--,.---~---~--,

factor. The produced spin-polarized 17B fragments
were transported to the final focus of RIPS, and werethen implanted in a single-crystal Mg stopper. The
measurement of the Q moment for 17B was performedby observing the nuclear magnetic resonance via thechange in the angular distribution of jJ-rays (jJ-NMR
method).
The experimental result is shown in Fig. 1. From theresult , leqQ/hl = 138.1±4.7 kHz, the Q moment of 17B
was tentatively determined to be IQI = 38.8 ± 1.5 mb
by taking an electric field gradient (q) deduced from
Refs. 1 and 2.
The obtained value, Q( 17 B)exp, is very close to3B)exp , which is for an isotope whose neutron pshell is closed. On the other hand, shell model calculations overestimate
7B)exp by 60%, as shown in 'Fig. 2. The overestimation by shell-model predictions
is removed if the neutron effective charge is taken to been ~ 0.03, which is substantially smaller than standard
value en = 0.5 in sd shel1. 3) The small en is also supported by the result for Q(14B)exp and Q(1sB)exp previously reported by our group.4) It may be suggested

Qe

Qe

c

~

0.97

Cl

0.96

=>

0.95

!

0.94

I

0.

f

I

f

I

0.93

C

0.98 I------:~..;:........:~+---...:.....--_:__-RF'"off--

o~

0.97

0.
:::> 0.96
0.95
I

0.94 L...-_ _..-...-_ _...:..!~_ _~_ _---'-_ _- - - '
160
100
120
140
180
200

eqQ/h(kHz)Fig. 1. Up/down ratio of {3-ray intensities plotted as afunction of eqQ / h, observed for 17B implanted in a Mg
crystal.

*1 Tokyo Institute of Technology*2 Sony LSI Design Inc.
*3
*4
*5
*6

68

Sanwa Newtec Co., Ltd.
University of Tokyo
II.Physikalisches Institute of University, Germany
University of Leuven, Belgium

70
65
60
:c 55
50
+-'
C
45
Q)
E 40
0
E 35
Q
30
25

rID

PSDMK

,T' .,.s

PSDWBT... __ --

~ ~

expo

-

............ ~JC---~--~!
Present work

11

13

15
17
Mass number

Fig. 2. Comparison between the experimental (exp) andtheoretical Q moments for odd-mass B isotopes. The
experimental Q moments are assigned a positive sign
taken from the value of shell model calculations. The
experimental Q are almost constant against the mass
number. The value of QC 7 B) obtained in the present
work is considerably smaller than shell-model calculations with the effective interactions of PSDMK 5,6) and
PSDWBT,5, 7) with e p = 1.3 and en = 0.5.

that the core polarization induced by excess neutrons
tends to diminish as the neutron-richness increases.
References
1) A. Kitagawa et al.: Hyperfine Interact. 60, 869 (1990).
2) T. Minamisono et al.: Phys. Rev. Lett. 69, 2058 (1992).
3) B. A. Brown et al.: Annu. Rev. Nucl. Part. Sci. 38, 29(1988) .
4) H. Izumi et al.: Phys. Lett. B 366, 51 (1996).
5) Shell model code OXBASH, B. A. Brown et al.: MSU
Cycl. Lab. Rep. No.524 (1986).
6) D. J. Millener et al.: Nucl. Phys. A 255, 315 (1975).
7) E. K. Warburton et al.: Phys. Rev. C 46, 923 (1992).

69

RIKEN Accel. Prog. Rep. 34 (2001)

Determination of the 17 C Ground-State Spin froma g-factor Measurement
D. Kameda,*l K. Asahi, H. Ogawa,*l H. Veno, H. Miyoshi,*l K. Yoneda, Y. Watanabe,
N. Imai,*2 T. Suga,*l K. Ohno,*l W. Sato, K. Sakai,*l A. Yoshimi, K. Yogo,*lY. Kobayashi, A. Yoshida, T. Kubo, and M. Ishihara[17C, Ground state spin, ,8-NMR method]

The ground-state spin for 17 C has been studied using
several theoretical and experimental approaches. 1- 3)
Up to now, two candidates, J7r = 1/2+ and 3/2+ ,for the ground-state spin remain unexcluded. In order to pin down the spin for 17 C, a measurement of
the g-factor may playa decisive role, because it is extremely sensitive to whether the spin is 1/2+ or 3/2+.
In the present work, the g-factor of the 17 C groundstate was measured by means of the ,8-NMR method
using a spin-polarized fragment beam of 17 C.
The beam of 17 C was obtained from the fragmentation of 22Ne projectiles at an energy of
110 MeV/nucleon on a 93Nb target of 778 mg/cm 2
thickness. In order to produce spin polarized fragments of 17 C, the emission angle (8L) and the outgoing
momentum (PF) were selected for the fragments. For
the purpose of seeking the best 8L and PF settings to
obtain an optimized polarization, the polarization (P)of 17C was measured by means of the adiabatic fieldrotation of the holding field method4 ) before pursuing
a ,6-NMR search. As a result, at 8L = 3.8 ± 1.5° and
PF = 7.21- 7.66 GeV /c, a ,8-ray asymmetry change of
A{3P = -1.2 ± 0.4% was observed.
After confirming the polarization, the g-factor wasmeasured by means of the adiabatic fast-passage(AFP) method 5 ) of NMR. The 17 C fragments were
implanted in a cooled Pt stopper to which a static
magnetic field (Bo) of 99.56 mT was applied for theprecession of 17 C. The temperature of the stopper was
kept at around 75 K. An oscillating field was then applied for the stopper in a direction perpendicular toBo. Ig(17C)1 = 0.5054 ± 0.0024 was obtained from the,8-NMR spectrum shown in Fig. 1.
First of all, the Schmidt value is about 8-times larger
than the experimental g- factor, suggesting the groundstate spin to be different from 1/2. In fact, a more elaborate theoretical g-factor for the 1/2+ state from shellmodel calculations 5 ,6) with the PSDMK and PSDWBTinteractions, shown in Fig. 2, also greatly exceeds theexperimental g-factor. We can thus clearly exclude
the possibility of 1/2 for the ground-state spin fromthe experimental g- factor. Then, the only remaining
possibility for the ground state spin is 3/2. In Fig. 2,
the experimental g- factor indeed lies between the predictions for the 3/2+ state. We therefore conclude that
*1
*2

70

Tokyo Institute of Technology
University of Tokyo

0.714
0.712
0.710

.~ 0.708.... 0.706

Q:§ 0.704
0.702

80= 99.56 mT

0.700
0.698
0.696

375

380

385

390

395

frequency (kH)

Fig. 1. NMR spectrum obtained for 17 C, with bin widths(ol/jl/) of 0.01. For each experimental point the statistical error and the width of the frequency sweep are
indicated by the vertical and horizontal bars, respectively. The g-factor is obtained from 9 = hI/oj J.1N B o·
The I/o is the resonant frequency (I/o = 383.54 kHz).

Fig. 2. Comparison of the experimental g-factor (exp) for
17C with theoretical predictions (PSDMK, PSDWBT).
For the symbols distinguishing the theories, see figure.

the ground-state spin for 17C is 3/2.
References
1) D. Bazin et al.: Phys. Rev. C 51, 2156 (1998).
2) T. Baumann et al.: Phys. Lett. B 439, 256 (1998).
3) E. K. Warburton and B. A. Brown: Phys. Rev. C 46 ,
923 (1992).
4) H. Ogawa et al.: Phys. Lett. B 451 , 11 (1999).
5) H. Ueno et al.: Phys. Rev. C 53 , 2142 (1996).
6) B. A. Brown et al.: OXBASH , MSU Cycl. Lab. Rep.
No.524, (1986).

RIKEN Accel. Prog. Rep. 34 (2001)

Reaction Cross Sections of 17Ne
M. Fukuda,*l M. Mihara,*l K. Tanaka,*l T. Sumikama,*l S. Kudo,*l K. Matsuta,*l T. Minamisono,*lT. Izumikawa,*2 T. Suzuki,*3 T. Yamaguchi, T. Zheng, T. Onishi, A. Ozawa, and 1. Tanihata
NUCLEA.R REACTION: BeeoNe, 17Ne); E = 135 MeV/nucleon; Measured 17Ne reaction][cross sectIOns
17Ne has attracted much interest as a candidate fora proton-halo nucleus. Based on the tJ-decay data,
it was discussed that the ground state of 17Ne (In =1/2-) or the excited state of the daughter nucleus, 17F(In = 1/2+, Ex = 495 keV), has a proton-halo structure because the tJ-decay rate is strongly supressed. 1)
In order to clarify which nucleus has a proton halo, weinvestigated the nucleon density distribution of 17Ne
through a measurement of reaction cross sections.
The transmission method 2) was employed to measure the reaction cross sections of 17Ne. An unstable nuclear beam of 17Ne was produced by projectile
fragmentation of the 135 MeV /nucleon 20Ne primarybeam provided from the RIKEN Ring Cyclotron. N uclide selection was made through the RIPS (RIken
Projectile fragment Separator). A beam energy of
40 MeV / nucleon was chosen to gain large nucleonnucleon total cross sections of about three-times thoseat the LBL energies, around 700 MeV/nucleon. At
60 MeV / nucleon the cross sections take approximately
the middle values in between these two energies.
The experimental setup, the principles for particle
identification and for determining the reaction crosssections are basically the same as those used in theprevious study. 2) Particle counting and identification
before a reaction target were performed by two thin
Si counters for a tlE measurement and three parallelplate avalanche counters (PPACs) that provided timeand position information. Downstream of the reaction target , the identification was made from tlEtaken by Si counters and from the time-of-flight (TOF)
taken between the PPACs and plastic counters thatwere placed 1.7 m downstream from the reaction target. The energy loss in the reaction target was about
20 Me V / nucleon for both energies.
Analyses of the data are now in progress. Figure 1
shows one of the preliminary results for 17Ne on C
and Al targets at 63 MeV/nucleon, compared with the

*1
*2
*3

I

I

1800 -f

1700 -:c 1600

-

0

f-

-

-

E
b

a:

1500 f--

1400 f--

1300 ""+-

1200 ""
D

1100~----~------~----~C

AI
TargetFig. 1. Comparison between the experimental reaction
cross sections of 17Ne at 63 MeV/nucleon and the systematics for stable nuclei. Closed circles show thepresent data, and open squares the values from the Kox
formula.

systematics of reaction cross sections for stable nuclei
by Kox et at. 3 ) This figure indicates that the reaction
cross sections of 17Ne are enhanced by rv10% comparedwith the systematics for stable nuclei. However, thisenhancement does not seem to be so large as in thecases of 8B or 9C. The density distribution and detailed discussions will be given after completing theanalyses.
References
1) M. J. G. Borge et al.: Phys. Lett. B 317, 25 (1993).
2) M. Fukuda et al.: Nucl. Phys. A 656, 209 (1999).
3) S. Kox et al.: Phys. Rev. C 35, 1678 (1987).

Department of Physics, Osaka University
Radioisotope Center, Niigata University
Department of Physics, Niigata University

71

RIKEN Accel. Prog. Rep. 34 (2001)

Search for 21 B
A. Ozawa, T. Yamaguchi , T. Zheng, R. Kanungo, T. Onishi, T. Suda, 1. Tanihata, K. Yoshida, T . Suzuki,*1
T. Izumikawa,*1 T. Kato,*1 Y. Kawamura,*1 Y. Yamaguchi,*1 S. Momota,*2 and K. Kimura*3[NUCLEAR REACTIONS: gBe(40Ar, X) , E(40 Ar) = 94.2 A MeV]
Recently, we have surveyed the neutron separationenergies and the interaction cross sections for neutronrich nuclei in the p-sd and sd shell regions, and havefound some signature for a new magic number, N = 16,
near to the neutron drip line. 1) If N = 16 near to theneutron drip line is a magic number, very neutronrich 21 B may be bound.2) The nuclear structure of
21 B would be interesting, since its AjZ ratio is over 4,
which is the largest number among known nuclei. Because of the exceptional Aj Z value, an isotope searchwith a magnetic rigidity setting optimized for this particular nuclide has not yet been performed. Recent
developments of radioactive ion (RI) beam technology
now turn to allow searches for such nuclei located very
far from the stability line (for example, Ref. 3).
The experimental setup at RIPS is shown in Fig. 1.
The 40 Ar beam accelerated at the AVF and RIKEN
Ring Cyclrotron up to 94.2 AMeV reacted with a
471 mgjcm 2 thick Be target. The target thickness
was chosen to maximize the secondary beam intensities based on a semiempirical yield estimation by the
INTENSITY code. 4) The primary beam current was

40Ar Primary Beam" ~e Reaction Target

Wodger±l
PPAC~i;J

Q
S
D: Quadrupole Magnet: Sextupole Magnet: Dipole Magnet

FI-3 : Forcus 1-3

Fig. 1. Experimental setup at RIPS.
*1

*2
*3

72

Niigata University
Kochi University of Technology
Nagasaki Institute of Applied Sciences

monitored by an array of plastic detectors located nearto the production target. The typical primary beam
intensity was 33 pnA.
The reaction fragments were collected and analyzed
by RIPS operated in an achromatic mode with the
maximum momentum acceptance and solid angle. The
magnetic rigidity of the first half of RIPS was set at5.40 Tm in order to optimize the yield of the 21 B isotopes. To reduce the relative rates of light isotopes,
such as 3H, a rather thin aluminum wedge with a mean
thickness of 223 mgjcm 2 was used on the momentumdispersive focal plane (F1). The magnetic rigidity ofthe second part of the RIPS spectrometer was thereby
adjusted to 5.35 Tm.
Particle identification was performed by a standard
method on the basis of energy loss (fl.E) , time-offlight (TOF) and magnetic rigidity (Bp) measured foreach fragment. The positions of the fragments at F1
were recorded using a parallel-plate avalanche counter(PPAC) to determine the Bp values. The F1 PPAC
also provided a timing signal. The sensitive area of
the PPAC was 15 cm (H) x 10 cm (V) , the horizontal size of which covered a full rigidity acceptance of
6%. The charge-division method was applied for position reading. The fragmentation products reached
the achromatic focal point (F2) , where a plastic scinitillation counter (F2-Pl) with a thickness of 1.5 mm,
two silicon detectors (SSDs) with 0.35 mm thickness
each, and a PPAC with 10 cm (H) x 10 cm (V) effective area were installed. The TOF of each fragment
was determined from the F2-PI timing and F1-PPAC
timing. The two SSD detectors provided independent
energy-loss values (D.E). The magnetic fields at thetwo dipoles were monitored by NMR probes.
The Be production target was irradiated for 78 hours
in total. We clearly identified 17B and 19B isotopes
with 360 events counted for 19B. However, serious
backgrounds due to the scattering of light isotopes
complicate the identification of 21 B. Thus, further
analysis is necessary for any conclusive statements.
References
1)
2)
3)
4)

A . Ozawa et al.: Phys. Rev . Lett. 84, 5493 (2000).
M. Beiner et al.: Nucl. Phys. A 24 9 , 1 (1975).
H. Sakurai et al.: Phys. Lett. B 448 , 180 (1999) .
K. Siimmerer et al.: Phys. Rev. C 6 1 , 034607 (2000).

RI KEN Accel. Prog. Rep. 34 (2001)

Coulomb Dissociation of 23 Al
T. Gomi,* l T. Motobayashi,*l K. Yoneda, S. Kanno ,* l N. Aoi ,*2 Y. Ando ,*l H. Baba,*l K. Demichi,*lZ. FUlop,*3 U. FUtakami,* l H. Hasegawa,* l Y. Higurashi,*l K. Ieki,*l N. Imai,*2 N. Iwasa,*4 H. Iwasaki,*2
T ~ Kubo, S. Kubono,*5 M. Kunibu,* l Y. U. Matsuyama,d S. Michimasa,*5 T. Minemura,*l H. Murakami,*lT . Nakamura,*6 A. Saito,*l H. Sakurai,*2 M. Serata,*l S. Shimoura,*5 T. Sugimoto,*6
E. Takeshita,* l S. Takeuchi,*l K. Ue, *5 K. Yamada,*l Y. Yanagisawa,
A. Yoshida, and M. Ishihara[NUCLEAR REACTIONS: 208Pbe 3AI,p 22 Mg)208Pb, 51 A MeV; Coulomb dissociation]
We performed an experiment to determine the rateof the radiative 'capture reaction, 22Mg(p ,')')23 AI. We
employed an experimental technique of intermediateenergy Coulomb dissociation combined with a radioactive isotope beam of 23 AI.
It has been pointed out that the 22Na yields obtained
from observing the cosmic ')' rays are significantly lower
compared with the calculated value for the hot NeNa cycle e ONe(p ,')')21 Na(p ,')')22Mg(,8+v)22Na).1) This
discrepancy might be due to an ambiguity of the employed reaction rates. Therefore, it is important toexperimentally determine the rate of 22Mg(p,')')23 AI,
which might lead to a decrease of the amount of 22Na.
The ground-state spin and parity, J7f, of 23 Al is
known to be 5/2+ , and the proton separation energy is 125 keY. The first excited state (1/2+ ) is unbound, and the excitation energy has already beenmeasured to be 460 ± 60 ke V using the transfer reaction 24MgeLi,8He)23 AI. 2) This excitation energy being close to the proton separation energy, implies a
considerable contribution of the first excited state to
the reaction rate . In the present work we studied thereaction 23 AI(')',p)22Mg to determine the 1/2+ --+ 5/2+
transition probability of 23 Al using the Coulomb dissociation method.
The experiment was performed in the RIPS beamline. An 23 Al beam was produced by the projectile
fragmentation reaction of a 135 AMeV 28Si beam on a
1.11 g/cm 2 9Be target. The energy of the 23 Al beam
was 51 AMeV at the final focal plane, F3, of RIPS ,and the typical intensity was around 2 x 10 4 cps. The
purity of the 23 Al beam was about 7%. The 23 Al nucleus and a main contaminant, 22Mg (56%) , were separated using time-of-flight (TOF) information obtained
from the signals of the cyclotron RF and of a 0.5 mm
thick plastic scintillator located at the focal plane, F2.
The 23AI beam bombarded a 80mg/cm 2 208Pb target located at F3. A 38 mg/cm 2 12C target was also
used to estimate the contribution of the nuclear interaction. The position and incident angle of the beam at
*1
*2

*3
*4

*5
*6

Rikkyo University
University of TokyoATOMKI, Hungary
Tohoku University
Center for Nuclear Study, University of Tokyo
Tokyo Institute of Technology

the target were measured by two sets of parallel-plateavalanche counters placed upstream of the target. A
stack of sixty-eight NaI (TI) scintillators was placedaround the target to measure the deexcitation ')' rays.
The products of the breakup reaction, 22Mg and a proton, were detected by a silicon telescope and a plastic
scintillator hodoscope 3) located 56 cm and 4 m downstream of the target.
The telescope consisted of four layers of 0.5 mm
thick silicon detectors.
The detection area was
150 x 150 mm 2 with a vacant area of 50 x 50 mm 2 inthe center. This arrangement enabled us to detect thereaction products scattered at angles larger than 2.5 0 ,by suppressing the detection of the secondary beam nuclei. As the first and second layers, position-sensitive
detectors were used. They were divided into strips horizontally and vertically, respectively. The width of the
strip was 5 mm, which corresponds to an angular resolution of 9 mrad in the laboratory frame . We usedsingle-element detectors as the third and fourth layers. The reaction products, 22Mg, were implanted into
the fourth layer, so that the telescope provided .t1EE information. The hodoscope consisted of .t1E andE plastic scintillators of 5 mm and 60 mm thicknesses.
They detected light reaction products which punchedthrough the silicon telescope .
The particle identification of heavy reaction products was performed by the .t1E-E method using a silicon telescope, while the light reaction products, such as
protons, were identified by the TOF-.t1E and TOF-E
method using the scintillator hodoscope. The energyof 22Mg was obtained from the total energy depositon the silicon telescope and the velocity of the proton
was determined from the TOF information between
the target and the hodoscope. In order to deduce therelative energy of the breakup reaction products measured in coincidence, the momentum vectors of the particles were determined from their energies combinedwith the hit position on the silicon telescope.
An analysis of the data is now in progress.
References
1) H. Schatz et al.: Phys. Rev. Lett. 79, 3845 (1997).
2) M. W iescher et al.: Nucl. Phys. A 4 84, 90 (1988).
3) 1. Hisanaga et al.: RIKEN Accel. Prog. Rep. 31, 162(1998) .

73

RIKEN Accel. Prog. Rep. 34 (2001),a-Delayed Proton Decay of 24Si
V. Banerjee,*1 T. Kubo, A. Chakrabarti,*1 H. Sakurai~ A. Bandyopadhyay,*1 K. Morita, S. Lukyanov,*2
K. Yoneda, H. Ogawa, and D. Beaumel*3[NUCLEAR STRUCTURE; 28Si+Be, Proton-rich nuclei, ,6-delayed protons],6-delayed proton spectroscopy has provided very
useful information for nuclear structure model calculations and for calculations of the nuclear reaction network tracing the elemental nucleo-synthesis in the rp
process. The ,6-delayed proton decay of 24Si, the subject of the present study, has already been studied at
GANIL 1 ) using the projectile fragmentation reaction
for production and the projectile fragment separator
for the selection of 24Si fragments, which were ultimately stopped in an active detector for the study ofdelayed proton spectrum. This methodology, althoughextremely powerful, has the undesirable feature of very
high ,6-ray background 1) which adversely affects the
proton spectrum, especially below about 2 MeV.
We have employed a new experimental technique 2)
to eliminate the high ,6-ray background in a measurement of delayed protons from 24Si. The 24Si fragments
after separation in the RIKEN Projectile Fragment
Separator (RIPS)3) were implanted at a grazing angleof 15 degrees in a 2.6 J.Lm Al stopping foil placed parallel to a gas boE-Silicon E telescope used for a delayed
proton measurement along with suppression of the ,6background. Prior to implantation in the AI-stopping
foil, the fragments were made to pass through a set of
Al foils whose total thickness was carefully tuned toserve the dual purpose of energy degradation and filtering out of the isotones - 22Mg and 21 Na completely
and 23 Al to a great extent.
24Si fragments were produced by bombarding a
100 MeV ju 28Si beam of intensity 20 pnA on a
552 mgjcm 2 thick 9Be target. RIPS was operated in
the achromatic mode with an aluminum wedge degrader of thickness 221 mgjcm 2 and a momentum acceptance of 0.125%. The isotope identification in flight
was done from the boE-TOF spectrum. The beam waspulsed ON for 200 ms and a delayed proton measurement was carried out during a beam OFF period of
200ms.
The I-dimensional proton energy spectrum for ,6delayed protons from 24Si projected from the protonband in 2-dimensional boE-E plot is shown in Fig. 1.
The high quality of the proton spectrum in terms of almost complete ,6-rejection is clearly evident. The halflife of 24Si was determined to be Tl / 2 = 139 ± 18 ms,

*1
*2
*3

74

Variable Energy Cyclotron Centre , India
Joint Institute for Nuclear R esearch , Russia
Institut de Physique Nucleaire, France

100

10

I

80
2

I
60
~

§
0

U
40

20

1

2

3

4

5

6

Delayed Proton Energy Ep (MeV)
Fig. 1. ,B-delayed proton spectrum from the decay of 24Si.

in good agreement with a previous measurement of
140 ms. 1) The peaks numbered 9 and 12 in Fig. 1 are
two new proton peaks observed in the present work.
Two new levels in 24 Al at energies of 5.76 and 6.53 MeV
are also proposed on the basis of transitions from theselevels to the 1.87 MeV level in 23Mg. The excitation energies are deduced by adding the recoil energies to theobserved proton decay energies. The level at 5.43 MeV,
which could not be unambiguously assigned in a previous study,1) has been assigned on the basis of a clear
peak at 3.42 MeV. The level energies and the relative
intensities deduced on the basis of present study arein overall good agreement with those from the earlier
study l ) and the shell-model calculations of Brown. 4)
References
1) S. Czajkowski et al.: Nucl. Phys. A 616, 278c (1997).
2) V. Banerjee et al.: Phys Rev. C 63 , 024307 (2001).
3) T. Kubo et al.: Nucl. Instrum. Methods Phys. Res. B
70, 309 (1992).
4) B. Brown: private communication.

RIKEN Accel. Prog. Rep. 34 (2001)

Spectroscopy of 34Si with the (d, d') Reaction in Inverse Kinematics
N. Iwasa,*l T. Motobayashi,*2 H. Sakurai,*3 H. Akiyoshi, Y. Ando,*2 N. Aoi,*3 H. Baba,*2 N. Fukuda,*3
Zs. Fi.ilop,*4 U. Futakami,*2 T. Gomi,*2 Y. Higurashi, K. Ieki,*2 H. Iwasaki,*3 T. Kubo, S. Kubono,*5
H. Kinugawa,*2 H. Kumagai, M. Kunibu,*2 S. Michimasa,*5 T. Minemura,*2 H. Murakami,*2 A. Saito,*2
S. Shimoura,*5 S. Takeuchi ,*2 Y. Yanagisawa, K. Yoneda, and M. Ishihara

From recent experimental and theoretical studies,the 34Si nucleus is known to be located just outside ofthe "island of inversion", and its ground state has aclosed 7r(Od 5 / 2)6 v (sd)12 configuration.1) On the other
hand, a(deformed) intruder state was suggested
to lie between the 2t state at 3.328 MeV and theground ot state in order to explain the small B (E2;0+ ---7 2+) measured at MSU. 2) A recent calculation
by Caurier et al. predicted this intruder state to located at 1.8 MeV. 3) We carried out an experiment of
the 34Si( d, d') reaction in the inverse kinematics tosearch for the intruder state by reconstructing the level
scheme for 34Si.
A radioactive 34Si beam was produced by the fragmentation of an 40 Ar beam at 95 MeV lu in a gBe
target with a thickness of 370 mg/cm2 . The beam
was isotopically separated by the RIKEN projectilefragment separator (RIPS). Particle identification of
the secondary beam was performed event-by-event using the time-of-flight (TOF) and ~E information of
two plastic scintillators with a thickness of 0.3 mm installed at the second and third foci (F2 and F3).
A liquid-deuterium target with a thickness of
150 mg/cm 2 was bombarded by the 34Si beam.
The beam energy at the center of the target was
40.9 MeV lu. The scattered 34Si was measured by four
sets of silicon counter telescopes arranged in a 2 x 2 matrix placed 135.7 cm downstream from the target. Each
telescope consisted of four layers of ion-implanted silicon detectors with an effective area of 50 x 50 mm 2 anda thickness of 500 /-Lm. The scattering angle and TOFof the scattered 34Si were measured by a parallel-plateavalanche counter (PPAC) placed in front of the silicondetectors. The scattered 34Si stopped in the second or
third detector. Particle identification of the reaction
products was achieved by utilizing the TOF-~E and~E- E methods.
The de-excitation 1'-rays were detected by a NaI(TI)
array surrounding the target from 40 to 138 degree incoincidence with 34Si detected by the silicon counter
telescope. The NaI(TI) array consisted of 68 NaI(TI)
crystals with a rectangular shape (6 x 6 x 12 cm 3) coupled to 5.1 cm ¢ photomultiplier tubes. A lead shield

ot

*1

*2

*3
*4

*5

Tohoku University
Rikkyo University
University of TokyoATOMKI, Hungary
Center for Nuclear Study, University of Tokyo

2000

preliminary

1800,........,1600
~1400

~1200

L..-fooocr.;'"0 800~.~ 600

~400

200
0

0

2000

4000

EiMeV ]
Fig. 1. Doppler corrected , -ray spectrum in coincidencewith 34Si, produced by the 34Si(d, d') reaction.

with a thickness of 5 cm surrounded the NaI(TI) arrayfor background reduction. The background from neutrons produced in the target was reduced by using the
TOF between the target and the NaI crystals.
Figure 1 shows a Doppler-corrected, spectrum measured in coincidence with the scattered 34Si detectedby the silicon detectors. The 3328 ke V and 929 ke V ,rays are known to be the 2t ---7 ot and 4257 ke V ---7 2ttransition, respectively. 4) Recently, the , lines of the591, 1053, 1193, 1435, 1715 and 2696 keY were foundby /3-, measurements at ISOLDE.5) These l' lines wereobserved in this figure. The 591 , 1193, and 2696 keY, -rays were obviously measured in coincidence withthe 3328 keY 1'-ray. Assuming that the
intruderstate is in between the first 2t state at 3.328 MeV andthe ground state, as suggested by Caurier et al., 3) the
1435 keY line is a candidate for the---7transition
among them. A careful analysis of the ,-1' correlation
is in progress to establish the level.

ot

2t ot

References
1) Y. Utsuno et al.: Phys. Rev. C 60, 054315 (1999).
2) R. W. Ibbotson et al.: Phys. Rev. Lett. 80, 2081 (1998).
3) E. Caurier et al.: Phys. Rev. C 58, 2033 (1998).
4) R. B. Firestone et al.: Tabl e of Isotopes, 8th ed., 1998
update, (Wiley, New York, 1998).
5) S. Nummela et al.: preprint CERN-EP /2000-73 (2000).

75

RIKEN Accel. Prog. Rep. 34 (2001)== 16, Near to the Neutron Drip Line

New Magic Number, N

A. Ozawa, T. Kobayashi,*l T. Suzuki,*2 K. Yoshida, and 1. Tanihata[Magic number, Neutron separation energies, Interaction cross-sections]
Recent experiments using a radioactive isotope
beam (RI beam) show some signature of the disappearance of the N = 8 and N = 20 closed shell. 1 ,2)However, no appearance of a magic number has beenshown experimentally so far, although some new magic
numbers were theoretically predicted 25 years ago. 3 )Recent improvements of RI beam techniques allow us
to measure the mass and the interaction cross-sections(()d for nuclei on the neutron drip-line or close to the
drip-line for Z ::; 8. Thus, we have surveyed the neutron separation energies (Sn) and ()I for neutron-richp-sd and sd shell region to investigate a new magic
number.
A neutron (N) number dependence of observed Sn 4)
for nuclei with N ::; 25 is shown in Fig. 1. A magic
number appears as a decrease of Sn along with an increase of N . The traditional magic numbers (N =8, 20) are clearly seen close to the stable nuclei as
breaks in the small isospin (Tz) lines. However, thebreak at N = 8 (N = 20) disappears at T z = 3/2(Tz = 4), which is also known concerning other experimental quantities. A break in the Sn line appears at
N = 16 for T z ::; 3, as shown in Fig. 1, which indicatesthe creation of a new magic number in N = 16 near to
the neutron drip-line.

10

20

N
-'r15<----;1-'6<-~1'r'-7_-T
18"----';19

1400
1300
1200
1100
1000 1----+--+--+----+--+--+----+--1
1500
Na
1400
1300
1200
1100 1----+--+--+---+--+--+----+----1
1400
Ne
1300

M~

~,

1200
1100
1000 1----+--+--+----+--+--+----+----1

~:

~

::
F
1100
1000 1---+--+--+--+--+--+--+----1
1400

~~~

1100

I

~,

0
______:

1000 1----+--+--+---+--+--+----+----1
1400
N
1300
1200
1100
1000 '-----'-_-'--_-'---------"--_-'--_.L---L_----'
11
12
13
14
15
16
17
18
19

N

Fig. 2. Neutron (N) number dependence for experimentallyobserved (71 for N to Mg isotopes on C targets.

12(a) odd N, even Z

15oo1'r1 _..,.,
12"---41=-.3---'1>r-4_

T z = 112

8
6
4

:>
6

2

C1l

C")

0
12
10

Tz = 1I

Tz = 2T z =3

6

I

4

Tz=~
T z =5

2
0
5

15

10

20

25

N

Fig. 1. Neutron (N) number dependence for experimentallyobserved Sn for nuclei with odd N and even Z (a) andodd N odd Z (b).
*1
*2

76

Tohoku University
Niigata University

In Fig. 2, a N number dependence of experimentallyobserved ()I for N to Mg isotopes is shown. 5 ) We observed a steep increase of ()I from N = 14 to N = 15
for N to F isotopes although, for Ne to Mg isotopes,
no steep increase for ()I is shown. This anomalous increase at N = 15 for N to F suggests that a 2S 1 / 2 orbital is dominant in the valence neutron of the nuclei.
This conclusion also supports the creation of a new
magic number at N = 16 near to the neutron dripline, since a clear single-particle structure is suggested
for N = 15. At weakly bound N = 16, 2S 1 / 2 and Id 5 / 2
orbitals are filled by neutrons, leaving a large gap to
the Id 3 / 2 orbital.
References
1)
2)
3)
4)

T. Motobayashi et al.: Phys. Lett. B 346, 9 (1995).
A. Navin et al.: Phys. Rev. Lett. 85 , 266 (2000).
M. Beiner et al.: Nucl. Phys. A 249, 1 (1975).
G. Audi and A. H. Wapstra: Nucl. Phys. A 595, 409(1995) .
5) A. Ozawa et al.: Nuel. Phys. A, in press.

RIKEN Accel. Prog. Rep. 34 (2001)

Deeply Bound Is and 2p States of 7r- in 205Pb
H. Geissel,*1 H. Gilg,*2 A. Gillitzer,*2 R. s. Hayano,*3 s. Hirenzaki,*4 K. Itahashi,*5 M. Iwasaki,*5 P. Kienle,*2
M. Miinch,*2 G. Miinzenberg,* 1 w. Schott,*2 K. Suzuki,*3 D. Tomono,*5 H. Weick,*1 T. Yamazaki,
and T. Yoneyama*5[Pion bound states, Pion transfer reaction]
Following the first successful observation of deeply
bound 1[- states in 207Pb in the 208Pb(d, 3He) reaction
at Td = 600 MeV, 1- 4) we carried out another experiment with a 206Pb target. The previous experimenthas clarified that (1) the deeply bound 1[- states (Isand 2p) in 207Pb indeed exist with narrow widths 5,6)
and that (2) they are produced in the (d,3He) reaction, as theoretically predicted. 7,8) Since this reaction produces deeply bound states of configurations(nl)7[(n'l');;1 at a small momentum transfer, the observed spectrum in the previous experiment is rather
complex due to the 3P1/2 and 3p3/2 neutron holes separated in energy by 0.89 MeV. The present experimentusing 206Pb was purposely undertaken in view of thegabsence of the 3P1/2 hole. )The Fragment Separator System of GSI was used asa high-resolution spectrometer at zero degree with sufficient particle identification capability. There was nobackground of instrumental origin. The observed spec-

trum, presented in Fig. 1 and Fig. 2, shows two wellresolved peaks of the Is and 2p pionic components.
The absolute energy scale was calibrated by using thep(d,3He}7To reaction, which exhibited a monoenergetic
peak in the same spectrometer setting. The instrumental uncertainty in the missing mass energy was
0.04 MeV. The instrumental resolution was estimated(a)(2p)1t-®{f S/2 ,P,/2' ~/2)~1

I

15

en
>Q)

(1s) -®(f
1t

5/2

.P. P
112

3/2

(3P.3d.4P····}lt-

r1n

I

1

~

~10

.=!.

8'

"0

W
"0

20~~~~-r~~~~~~~~,~-r~~i5 ...

~_I\ll!tl!I~

1t- threshold(2p)1t-®(f

5/ 2,p, p )n-1
112

11

~15
(/l

>

3/2

3

(b)
",."",),(2f7/2)n -1

Q)

~

~
........ 10

Cl

"0

W
~

(1 s)1t-®(f

5/ 2

,p ,p
112

3/2

r1n

~

'0

~ 5

130

Fig. 1. Excitation spectrum of the 206Pb(d,3He) reaction
measured at an incident deuteron energy of 600 MeV.
The 7r - emission threshold is shown by the vertical broken line.
* 1 Gesellschaft fUr Schwerionenforschung, Germany
*2
*3

*4
*5

Physik-Department, Technische Universitiit Miinchen , Germany
Department of Physics, University of Tokyo
Department of Physics, Nara Women's University
Department of Physics, Tokyo Institute of Technology

131

132

133

134

135

136

137

138

139

Excitation Energy [MeV]Fig. 2. Fitting result of the excitation spectrum. (a) The
data points are fitted by the solid curve, which was obtained in the fit range indicated. The broken and dotted curves are the (ls)1I" and (2p)1I" components, respectively. (b) The partial contributions from the four neutron hole states, shown in the same scale as (a). Eachcomponent is a sum of two Lorentzian's corresponding
to the (ls)1I" and (2p)1I" states folded by experimental
resolution.

77

to be 0.32 ± 0.05 MeV FWHM.
The Is and 2p peaks were decomposed by assuming
the configurations and their relative spectroscopic factors calculated theoretically in Ref. 9 with the binding
energies B Is and B 2p and widths r ls and r 2p as freeparameters. The fitting of the experimental data withtheory is excellent and the deduced binding energies
and widths are:

References
1)
2)
3)
4)
5)

(1)
(2)
(3)
(4)

6)

The obtained binding energies and widths were used

9)

B I s = 6.768 ± 0.044 (stat.) ± 0.045 (syst.),r ls = 0.78 ± 0.14 (stat.) ± 0.055 (syst.),B 2p = 5.110 ± 0.016 (stat.) ± 0.040 (syst.) ,r 2p = 0.37 ± 0.04 (stat.) ± 0.05 (syst.).

78

to deduce the strength of the s-wave (local) potential.

7)
8)

T. Yamazaki et al.: Z. Phys. A 355, 219 (1996).
T. Yamazaki et al.: Phys. Lett. B 418, 246 (1998).
H. Gilg et al.: Phys. Rev. C 62 , 025201 (2000).
K . Itahashi et al.: Phys. Rev. C 62 , 025202 (2000).
H. Toki and T. Yamazaki: Phys. Lett. B 213, 129(1988).
H. Toki, S. Hirenzaki, T. Yamazaki, and R. S. Hayano:
Nuel. Phys. A 501 , 653 (1989).
H. Toki, S. Hirenzaki, and T. Yamazaki: Nuel. Phys. A
530 , 679 (1991).
S. Hirenzaki, H. Toki, and T. Yamazaki : Phys. Rev. C
44, 2472 (1991).
S. Hirenzaki and H. Toki: Phys. Rev. C 55 , 2719 (1997).

2. Atomic and Solid-State Physics

RIKEN Accel. Prog. Rep. 34 (2001)

Charge Transfer in F 2 + Ions Colliding with He Atoms below
keY lu Energies and Its Reverse Process
J. P. GU,*1 G. Hirsch,*1 R. J. Buenker,*1 M. Kimura, I. Shimamura, C. M. Dutta,*2 and P. Nordlander*2
Charge transfer processes for heavy ion impact areimportant basic processes in various scientific and technological applications. 1) Over the past decade, an intense effort from the atomic physics community toward a better understanding of scattering dynamics
over a wide range of energies has resulted in a basic understanding of compiled experimental cross section data. As a consequence, a large number of extremely interesting new physics has emerged making
the field prosperous and lively. However, although
there have been a large number of studies of collisions of H+ , He q+ , ... , oq+ ions with simple atoms andmolecules, relatively few investigations have been performed on other heavy ions (Z > 9) because of, inpart, some difficulties in producing these ions in experiments. However, scattering processes by these ionsare particularly interesting and important because notmuch of spectroscopic information for the ions is available, and these complex systems possibly lead us to a
new phenomenon of collision physics.
Recently HF molecules have been detected in interstellar medium, and the origin and formation mechanisms are sought.2) From this observation, therefore,
Fq+ ions are expected to be present in interstellar environment , and to playa subtle role for astrochemistry. Also fluorine ions (Fq+) and atoms are known
to be present in biological systems including the human body, and the knowledge of its interaction withother atoms and molecules are needed for medical andbiological study. As a part of our heavy-ion collision project, we present a theoretical investigation on
charge transfer in collision of Fq+ ions with He atoms
based on a molecular state expansion method below
1 keY lu. The processes we are concerned with are:(i) the ground-state ion impact:

all information of the effect from these states whenmodeling scattering dynamics. The adiabatic potential curves of HeF 2+ are obtained by employing the abinitio multireference single- and double-excitation configuration interaction (MRD-CI) method,3) with configuration selection at a threshold of 5.0 x 10- 8 Hartree.
The two electrons in the first (lowest) molecular orbital(MO) are kept inactive in the present CI calculation,and the highest MO is discarded. A semiclassical MO
expansion method with a straight-line trajectory of theincident ion was employed to study the collision dynamics. In this approach, the relative motion of heavy
particles is treated classically, while electronic motions
are treated quantum mechanically. By solving the coupled equations numerically, we obtain the scattering
amplitudes for transitions: the square of the amplitude
gives the transition probability, and integration of theprobability over the impact parameter gives the crosssection. Charge Transfer Cross Sections F2+ + HeeS)
collisions is summarized and representative results for
the Quartet state are shown in Fig. 1 (total, 14~ ­and 14 II cross sections): This is an exothermic process. The cross sections increase four-fold as the incident energy increases from 0.1 keY lu to 0.6 keY lu,
but are found to be rather small with a magnitude of2 x 10- 16 cm 2 even at the highest energy studied. Thisis a manifestation of the weak coupling which connects
between the initial and charge transferred states because both the projectile F2+ and the target He atom
have tight shells. The partial cross sections for 14~- islarger than those for 14 II, and they show a structure atcollision energies between 0.2- 0.3 keY lu. This is an effect of interference between the initial 24~- and 14~2.5

r+ + He Quartet state

(la)
2

and
(ii) the excited-state ion impact:F2+(2D) + HeeS) ---t F+ + He+.

"'s
:<J

(lb)

The energy defect between the ground F 2+ (4S) and theexcited F2+eD) states is approximately 4.3eV. Therefore these two ions may be produced simultaneously
through ,-ray- or ion-impact ionization in natural environment like the astrophysical environment, or laboratory plasma. Hence it is necessary to put together*1*2Theoretische
Chemie,Bergische
UniversitaetGesamthochschule Wuppertal, Germany
Department of Physics and Rice Quantum Institute, Rice
University, USA; 1.5

t 4 r-

Total.

=
~

L

<J

~

'"'"<:>'" 0.5

U...... ".

-

... ~

..---

..---

/,

t 4n

.-~

0
0

0.1

0.2

0.3

0.4

0.5

0.6

E (keV/u)Fig. 1. Charge transfer cross sections for the process (la)in F 2 + + He collisions.

79states. The 14 rr state is not involved in the dynamics.
The total cross sections reflect this structure. This iscaused by the strong peak in the coupling of this 14~­channel with the incoming channel at R rv3.7 ao. The
partial cross sections for 14 rr increase with the collisionenergy monotonously.
References
1) R. K. Janev:

80

Review of Fundamental Processes andApplications of Atoms and Ions (World Scientific, Singapole, 1993).
2) R. K. Janev: Atomic and Molecular Processes in Fusion
Edge Plasma (Plenum Press, New York, 1995).
3) R. J. Buenker and S. D. Peyerimhoff: Theor. Chim.
Acta 35,33 (1974); Theor. Chim. Acta 39,217 (1975);
R. J. Buenker: Int. J. Quantum Chern. 29 , 435 (1986).

RIKEN Accel. Prog. Rep. 34 (2001)

Theoretical Calculation of Double Electron Transfer Processes
in Collisions of He 2 + with Mg
S. Sakaguti, *l K. Ohtsuki,*2 and T. Watanabe*3-199.4

We study theoretically a double electron transfer
process, namely
He 2+ + Mg(3s3s) --+ He**(nln'l') + Mg2+,
induced by collision of a He 2+ ion with a neutral Mg
atom at collision energies of 15- 40 ke V. In this process,valence electrons of the Mg atom are transferred into
a doubly excited state (n, n' :::: 2) of He.
This work was stimulated by experimental study by
Iemura et al. 1 ,2) They measure energy spectrum of theAuger electrons ejected in the collisions of He 2+ withalkaline earth atoms Mg, Ca, Sr, and Ba.
In this energy region, the speed of the electronic motion is considered to be fast compared with the relative
motion of the atomic cores. Hence, coupled equations
derived from a molecular orbital (MO) basis are employed. Also, the de Broglie wavelength of the relative
motion of the atomic ~ores is short enough for treating this motion classically, and its trajectory is nearly
along a straight line. Therefore, we adopt the straightline-trajectory impact parameter method.
The assumption of the straight-line trajectory leads
to the relation R = b + vt between time t and theinternuclear distance vector R, where b is the impact
parameter and v is the relative velocity between the
nuclei.
The Schrodinger equation for the electronic state ofthe (MgHe)2+ system
i :t 'II el ( r, t) = H el 'It el ( r, t),

was considered, where r denotes the position vector of the electrons collectively and Hel is the electronic Hamiltonian. The total electronic wave function'II el ( r, t) was expanded asnin terms of the eigenfunctions Wn(r; R) satisfying thetime-independent Schrodinger equation HelWn(r; R) =En(R)wn(r ; R).
In order to express the adiabatic electronic states

*1

*2
*3

=i
~
~

-199.45-199.5

>.
~

Q)

c

w

-199.55

()

'c

e

u

-199.6

Q)

iIi-199.65-199.7

5

10

15

20

25

30

Internuclear Distance R [a.u.]

Fig.!. Adiabatic potentials of (MgHe)2+. The origin of energy is the completely broken-up state. The symmetryof each state is 1 ~.

'ltn(r; R), molecular orbitals were constructed fromlinear combinations of atomic orbitals (LCAO-MO);Slater-type functions (STF) were used as basis functions for constructing atomic orbitals. The basis functions of the Mg atom were taken from Clementi andRoetti 3) and those of the He atom were determine by
us. The adiabatic states were constructed by freezing the inner shell electrons and by expressing the twoouter electrons as a linear combination of two-electron
configurations. We use ALCHEMY n 4 ) to calculate
adiabatic potentials (Fig. 1). We will compute thetransition matrix elements to obtain the coefficientsen (t, b) of the electronic states by solving the first-ordercoupled differential equations, and will compute thecross sections,

References
1) K. lemura et al.: Physica Scr. T 73, 205 (1997).
2) K. lemura et al.: submitted to Phys. Rev. A .
3) E. Clementi and C. Roetti: At. Data and Nucl. Data
Tables 14, 177 (1974).
4) A. D. McLean et al.: in Modern Techniques in Computational Chemistry: MOTECC-91 (IBM Corporation
Kingston , New York , 1991) , p. 233.

Graduate School of Science and Engineering, Saitama University
University of Electro-Communications
Japan Science and Technology Corporation

81

RIKEN Accel. Prog. Rep. 34 (2001)

Laser-Assisted Formation of Antihydrogen
R. J. Whitehead,*1 J. F. McCann,*2 and 1. Shimamura
The interactions of antiprotons p with simple atoms
has been a subject of great importance since the development of low-energy p beams. In particular , theformation of cold antihydrogen H = (p, e+) in reactive
collisions of p with positronium Ps = (e+, e- ), i.e.,

p + Ps ---+ H + ehas been of great interest because of the possibility ofthe spectroscopy of H, which would lead to the information on fundamental principles of physics including
parity violation .1)
We have simulated the above process by the classicaltrajectory Monte Carlo (CTMC) method. Our maininterest is to investigate the effects of the presence of alaser on the H formation rate . The main advantage of
the CTMC method is that it is relatively easy to execute for three-body systems without approximation
further than the classical treatment. Converged fully
quantum mechanical or semi-classical calculations often require large-scale numerical calculations, which
may not always be feasible.
The presence of a laser introduces a perturbation
which, in the dipole approximation and with the choiceof the length gauge, has the form

H' = -F(t) cos(wt + <p)

L Ziri . e,

where e is the direction of polarization of the laser, w is
the angular frequency, <.p is the phase, F(t) is the timedependent electric field amplitude, and Zi and ri are
the charge and the position vector of the ith particle
in the three-body system. The peak field (Fmax) is
related to the light intensity (1) by Fmax = y'2I/cQc.
In this work the field was ramped smoothly on and off
over a time scale T, the total time period tlT being
chosen to be longer than the collision time:F(t)The CTMC procedure is well documented,2) but
briefly it consists of the following steps: (1) Monte
Carlo sampling of initial conditions, (2) integration of
the classical equations of motion, and (3) identificationof the exit channel in the asymptotic region t ---t +00.

*1
*2

82

Department of Physics, University of Durham, UK
Department of Applied Mathematics and Theoretical
Physics, Queen 's University of Belfast, UK

The dynamics can be solved by integration of theequations of motion in either the Hamiltonian or Lagrangian form. In fact it is simple and efficient towork with the six (independent) second-order differential equations of motion following directly from Newton 's second law. These were solved by resolving theequations into their Cartesian coordinates resulting in
12 first-order coupled ordinary differential equations.
The effect on p capture due to the presence of alaser has been studied in the Born approximation. 3)
However it has been established that for laser-freecollisions this model is inadequate at energies below
the ionization threshold. Nonetheless, calculations athigh energies using this approximation predicted anenhancement of capture in some cases by a factor of ten
or more. 3- 5 ) However, the laser intensities considered
have been shown to lead to rapid photoionization 6 )and thus to depletion of capture. We consider theprocess over the low energy range of interest to experiment. In particular , we investigate laser-assisted
formation of H at two p energies 1 keY and 15 keY ,for laser wavelengths of A = 248 nm and 1064 nm, andconsider linearly polarized light with alignment parallel to and perpendicular to the collision axis (directionof the p beam).
It was discovered that the addition of the laser field
led to enhancement of the formation of antihydrogenof the order of 4- 70% for a p collision energy of 1 ke V
and 8% for an energy of 15 keY with A = 248 nm. Certainly the classical model has shortcomings, howeverthese preliminary results are promising. It seems that
this process is worth studying with a quantal modelof low-energy laser-assisted p capture by Ps, or equivalently, laser-assisted e+ +H scattering leading to theformation of Ps, the latter being the reverse process ofthe charge conjugate of the former.
References
1) M. Charlton et al.: Phys. Rep. 241 , 65 (1994).
2) R. Abrines and I. C. Percival: Proc. Phys. Soc. 88, 861(1966); J. S. Cohen: Phys. Rev. A 27, 167 (1983).
3) S.-M. Li et al.: Phys. Rev. A 59, 1697 (1999).
4) S.-M. Li et al.: Phys. Rev. A 61, 067402 (2000).
5) S.-M. Li et al.: J. Phys . B 33, 4627 (2000).
6) L. B. Madsen and P. Lambropoulos: Phys. Rev. A 61,
067401 (2000).

RIKEN Accel. Prog. Rep. 34 (2001)

Effects of the Hyperfine Structure on Symmetric Scattering of
Muonic Atoms: Hyperspherical Close-Coupling Studies
A. Igarashi, *1 M. P. Faifman, *2 and 1. Shimamura
Symmetric collisions of muonic atoms in a hyperfine
state F with hydrogen isotope nucleipp,(F) + p -----+ pp,(F') + p,
dp,(F) + d -----+ dp,(F') + d,tp,(F) + t -----+ tp,(F') + t,

(1)
(2)
(3)

at low energies « 100 eV) take a special place in thegeneral picture of scattering processes in hydrogenisotope mixtures with negative muons. The cross sections of reactions (1)- (3) provide the important information necessary for proposals and analysis of various
experiments, in particular, on the precision measurements of the muon capture by hydrogen isotope nuclei and muon catalyzed fusion. The effective capture
rates and the neutron yields of the nuclear fusion in
muonic molecules, extracted from experimental data,
depend on the populations of the hyperfine states ofthe muonic hydrogen atoms and on the rates of transitions between them.
On the other hand, calculations of the cross sections for processes (1)- (3) would be a good test for
any computational method developed for the study of
Coulomb three-body systems. In fact, the ,cross sections for processes (1 )- (3) , calculated by use of different methods,l ,2) are in good agreement. However,these cross sections show discrepancies with the experimental data on spin-flip (F' =1= F) reactions (2) and(3).3-5)
The most intriguing is the spin-flip processdp,(F = 3/2) + d -----+ dp,(F' = 1/2) + d,

(4)

in reaction (2). The experimentally observed rates 5 ,6)of reaction (4) agree well between them but differ fromthe calculated ones by "'40%. According to the kinetics of muon-catalyzed fusion processes in deuterium,7)
the transitions between hyperfine states F = 3/2 andF = 1/2 of dp, atoms can proceed both through thespin-flip process(5)
and due to the back-decay process of the intermediately formed molecular complex (ddp,)dee in reaction

dp,(F) + D2 -----+ (ddp,)dee -----+ dp,(F') + D 2.

(6)

Then the observed spin-flip rates Ap pi may be decomposed into the contribution AFF~t from reaction (5) andthe contribution A'FF' from process (6) as

,

/\PPI
*1

*2

,scatt + /\pp'.
,be= /\ppl

The component A'Fpi extracted from measured dataagrees well with theory unlike the rates AFF~t .
One could mention that for real experiment a molecular target is used, and so it is necessary to take into
account not the "bare" nucleus in scattering calculations but the effects of the molecular structure. However, such an attempt could not resolve the existing
disagreement between theory and experiment.
This long-standing puzzle about the rates Appl requires a serious check of the calculations of spinflip cross sections. Most previous systematic calculations were done in the framework of the traditional
adiabatic-state expansion method. The well-known
problems with this method, such as the incorrectboundary conditions inherent in it, lead to the use ofa large number of states of the "two-center problem,"
including the continuum states, and a detailed analysisof the convergence of the obtained solution.
In the present work both elastic and spin-flip crosssections of reactions (1)- (3) were calculated with theclose-coupling method in the hyperspherical coordinates, as an extension of our previous work in Ref. 2.
The advantages and reliability of this method were
fully demonstrated in the previous publications. 2,8)
In fact , the cross sections calculated in the present
work turned out to agree fairly well with the resultsof the adiabatic-state expansion method, thus leaving the theory-experiment discrepancy still unresolved.
On the theoretical part, the molecular effect should
probably be considered seriously, now that reactions(1)- (3) have been treated quite accurately.
References
1) L. Bracci et al.: Muon Catal. Fusion 4, 247 (1989);
Phys. Lett. A 134, 435 (1989); J. S. Cohen: Phys. Rev.
A 43, 4668 (1991); C. Y. Hu et al.: J. Phys. B 28, 3629
(1995).
2) A. Igarashi , I. Shimamura, and N. Toshima: Phys. Rev.
A 58, 1166 (1998).
3) C. Petitjean et al.: Hyperfine Interact. 118, 127 (1999).
4) P. Ackerbauer et al.: Nucl. Phys. A 652, 311 (1999).
5) P. Baumann et al.: Phys. Rev. Lett. 70 , 3720 (1993);
B. Lauss et al.: Hyperfine Interact. 118, 79 (1999).
6) N. I. Voropaev et al.: Hyperfine Interact. 118, 135(1999) and references therein.
7) L. I. Men'shikov et al.: SOy. Phys. JETP 65 , 656 (1987).
8) A. Igarashi and N. Toshima: Phys. Rev. A 50, 232(1994); A. Igarashi, N. Toshima, and T. Shirai: Phys.
Rev. A 50, 4951 (1994).

(7)

Faculty of Engineering, Miyazaki University
Russian Research Center Kurchatov Institute , Russia

83

RIKEN Accel. Prog. Rep. 34 (2001)

Possible Binding of Positron with Molecules
M. Kimura, M. Tach ikawa, and 1. Shimamura
Study of positron scattering from molecules has attracted a significant interest recent years since theknowledge of interactions and dynamics is expected
to provide basic physics at much deeper level by acomparative study between positron- and electronscattering cases. However, very little knowledge andinformation for molecular processes by positron impact
have been attained due to the lack of systematic experimental and theoretical studies. Positronium (Ps)formation is a channel unique to positron impact which
has a threshold of (Ei - 6.8) eV (where Ei is an ionization potential of a target). One path for the Ps
formation is a direct process that is regarded as similar to charge transfer process in ion-atom collisions.
Another path is an indirect process that the positronis temporarily captured by the molecular field before it
escapes from it as the Ps , i. e., Ps formation via a resonance. After the Ps formation, the target molecule isleft as a molecular ion either in the ground or excitedelectronic state. For a majority of molecular ions, they
are known to strongly couple with dissociation channels, and hence, are not stable. After a short lifetime,they break up producing various smaller fragmented
species. The kind of species and their energy distributions after breaking-up should be quite different fromthose produced by electron impact. Therefore, the precise knowledge of dynamics for the Ps-formation andresonance from various molecular targets would be offundamental interest for atomic and molecular physics
as well as condensed matter physics. Therefore, it isextremely important to understand if positron can attach , at least temporarily, to molecules.
Recently, there are three independent experiments
which are strongly indicative of the presence of resonance or bound state of positron: (i) Sueoka andKimura 1) have observed a strong suppression of Ps
formation in fluorinated hydrocarbons (FHCs) compared to their hydrocarbon (HCs) counterparts in theratio of Ps formation cross section to total cross section
near Ps-formation thresholds. As the molecular size increases , these ratios of Ps formation to total from bothgroups are found to merge. (ii) Surko's group2) has
measured annihilation rates for various molecules bythermal positron impact below 1 eV, and has observed84

that annihilation rates differ significantly from HCs
to FHCs, in which the annihilation rates for HCs arefound to be grossly larger by four- five orders of magnitude than those for FHCs. Furthermore they have analyzed from their ,),-emission spectrum and speculated
that the annihilation tends to occur on C-H bonds in
HCs and on F atoms in FHCs. 2) (iii) Xu et al. 3 ) has carried out another type of positron scattering experimentfrom large molecules , in which they have detected theappearance of various types of fragments when low energy positron with the energy below Ps threshold wasintroduced into the target. The fragmentation may
occur through a resonance state. All three experimental findings that studied completely different aspectsof positron scattering may be interpreted consistently
by assuming the presence of the positron resonanceor bound state for FHCs. If a positron is assumed
to be trapped at the far end of the polarization potential where it is isolated from the rest of electrons,
then these resonance or bound states are likely to makea positron lifetime longer, hence reducing the annihilation or fragmentation . In a study of Ps formationin liquid halogen-substituted substrates, Wikander 4 )has found that in the liquid-FHCs, the Ps formation
rate decreases by 10% more in comparison with that inliquid-HCs. The basic underlying physics should sharethe same origin as in the three experimental results
above . In order to provide a rationale to these findings,
the theoretical study based on a quantum chemical
method based on the Hartree-Fock approach is underway to examine a possible bound state of positron. The
preliminary result clearly suggests that some moleculeswith a strong dipole moment such as LiH can indeed
bind a positron with a positron affinity of 0.0055 a. u.
References
1) O. Sueoka and M. Kimura: to be published in Phys.
Rev. A.
2) S. J. Gilbert, R. G. Greaves, and C . M . Surko: Phys.
Rev. Lett. 82, 5032 (1999); C . Surko: private communications (2000).
3) J. Xu, L. D. Hulett, Jr., T . A. Lewis, D. L. Donohue, S.
A. McLuckey, and O. H. Crawford: Phys. Rev. A 49,
R3151 (1994).
4) G. Wikander: Chern. Phys. Lett. 80, 361 (1981).

RIKEN Accel. Prog. Rep. 34 (2001)

Electron and Positron Scattering from CF3I Molecules below 600 eV
M. K. Kawada,* O. Sueoka,* M. Kimura, and 1. Shimamura
Perfluorocarbon (CmF n) molecules have been regarded as important and efficient gases for plasma
etching, and have been extensively used in semicond uctor .manufacturing ind ustries. 1 ) However, becauseof their long life in the stratosphere as well as in the atmosphere and hence the introduction of toxic gases into
the earth's environment , it has been decided to completely terminate the usage of these gases in the very
near future. Therefore, the development of an alternative new gas that is environmentally safe and efficient isurgently required. Strong candidates for these alternative gases are non-perfluorocarbon gases such as CF3I
because the molecule is known to be environmentallysafe and to easily release the CF 3 radical. To assess
the behavior of these molecules in the plasma environment, it is crucial to understand the fundamental spectroscopic properties of these molecules and their dynamics, particularly the electron scattering processes
at low to intermediate energies. Also , a complete setof cross-sectional data for a wide range of collision energies is necessary to assess and evaluate the role ofinelastic scattering processes. A comparative study between electron and positron scattering from molecules
can provide more detailed insight into interaction anddynamics, and hence is essential. Therefore, we conducted a comparative study of electron and positronscattering from CF 31 molecules for total and elastic
cross sections.
Electron Impact: Total cross sections (TCSs) for
electrons from CF3I molecules obtained at selected energies within the range 0.7-600eV are shown in Fig. 1
along with the previous experimental data. 2 ) Someinteresting general features of the present TCSs for
CF3I can be summarized: (1) The TCSs have a relatively large and broad peak at around 4- 11 eV , andthe curve drops sharply on both sides of this energy
range. The magnitude of the TCS sharply increases
from 20 x 10- 16 cm 2 at 0.8 eV to the maximum valueof 53 x 10- 16 cm 2 at around 5 eV, followed by a very
slow decrease until the energy reaches 11 eV, where it
has a value of 50 x 10- 16 cm 2 . (2) This large and broad
peak appears to consist of two small humps at approximately around 5 eV and 8 eV. (3) Several small structures can be seen at around 25 eV. The broad peak ataround 4- 11 eV is due to strong enhancement from the60· ele~tron I
I positrono•1111111111 Ionization

E (eV)
Fig. 1. Total cross sections of electron and positron impacts
on CF3I molecules. Electronic excitations, dissociative
attachment and ionization thresholds are also shown invertical lines.

shape resonances.
Positron Impact: TCSs for positron impact are also
included in Fig. 1. Over the entire impact-energy
range, the TeSs for positrons are always found to besmaller than those for electrons. Starting from a valueof 14 x 10- 16 cm 2 at 0.7 eV, the TCSs increase with a
step-like structure at around 2- 3 eV and continue toincrease to a maximum value at around 7 eV. This
step-like increase is attributable to the opening of anew positronium formation channel at a threshold of
3.43eV. A few structures can also be observed in theenergy region between 4 eV and 20 eV, and these are
attributable to the opening of new channels for a seriesof electronic excitations, and direct ionization where
each threshold corresponds to approximately 4.3 eV
and above, and 10.23eV. Other weak structures canalso be observed throughout the entire energy range.
References
1) L. C. Christophorou: Electron-Molecule Interactions
and Their Applications (Academic Press, New York,1984).
2) T. Underwood-Lemons, D. C. Winkler, J. A. Tossell,
and J. H . Moore: J. Chern. Phys. 100, 9117 (1994).

Graduate School of Science and Engineering, Yamaguchi
University

85

RIKEN Accel. Prog. Rep. 34 (2001)

Elastic Scattering of Electrons from Carbonyl Sulfide
M. Takekawa and Y. Itikawa *Due to its importance in a field of environmental
science, carbonyl sulfide (OCS) is one of the important molecules for a study of electron scattering. A
theoretical study is attempted to get detailed information about elastic scattering (more strictly, vibrationally elastic scattering, corresponding to the experimental data available) of electrons from OCS in thisinvestigation.
We mention the present theory here briefly. The details of the theory have been described elsewhere. I)
The fixed-nuclei, adiabatic-rotation approximation is
employed in the present calculation, that is, we freeze
the target nuclei throughout the collision. The electronic excitation probability of the target moleculeis expected to be smaller than the elastic scattering
probability in the present incident energy region 1.060.0 e V. Therefore, the target molecule is assumed tostay in the electronically ground state, in which the
OCS molecule is linear. The wave function of the incident electron in the body-fixed frame (i. e., the z-axis
is chosen along the molecular axis and the origin of
the coordinates is located at the center-of-mass of themolecule) is expanded in terms of the spherical harmonics to yield coupled differential equations for theradial part of the wave function. The coupled differential equations are solved with the scattering boundary
conditions to obtain the scattering matrix (S-matrix)
in the body-fixed frame. After the frame transformation from the body-fixed to the space-fixed coordinates, differential cross sections are obtained. The
closure method (with the adiabatic-rotation versionof the point-dipole-Born approximation) is adopted toconsider the effect of the long-range dipole interaction.
The effect is essential in the forward scattering region.
The interaction between an electron and the target
molecule is composed of three terms: static, exchange
and correlation-polarization potentials. For electron
exchange, a local model potential 2 ) is adopted. Use
is made of a parameter-free correlation-polarization
model 3 ) to take account of the target polarization.
This model is constructed by matching local, shortrange correlation potential to the long-range polarization potential. The former is evaluated in the local
density approximation of electron gas. The quantum
chemistry molecular orbital code GAMESS is used togenerate the multi-centered target wave function.
Figure 1 shows the present differential cross section

The Institute of Space and Astronautical Science86

100 rr---..-----..,----,------,---.----r--=-P--rre-se-n~t-=-.r:=...-_--"lKimuraBettega et al.
Kitajima et al.

L

C/)

EU

e- + DeS Differential cross sectionat £=10.0 eV

-c

b
c

o

U

10

Q)
C/)
C/)
C/)

e
U

]i

1:
~

~
i:5

o

~

~

~

00

100

1~

1~

1~

100

Scattering angle (deg.)

Fig. 1. Differential cross sections for the elastic scattering
at 10.0 eV.

(DCS) for the elastic scattering at an incident energy oflO.OeV. In this figure, the result of the present calculation is compared with the experimental DCS 4 ) and thetheoretical values obtained by the continuum-multiplescattering method 5 ) and by the Schwinger multichannel method. 6 ) The present result reproduces the experimental DCS fairly well and is also in a good qualitative
agreement with the other theoretical results except at
a scattering angle of 0°. The disagreement at 0° may
be due to the difference in the considerations of thelong-range dipole interaction in the different calculations. The present closure method does not take into
account the molecular rotation properly, but should be
reliable unless the scattering angle is extremely small.
In principle, a calculation considering the rotationaltransition is needed to evaluate the appropriate DCSs
in the forward scattering region for a polar molecule. 7 )References
1) M. Takekawa and Y. Itikawa: J. Phys. B 29, 4227
(1996).
2) S. Hara: J. Phys. Soc. Jpn. 22, 710 (1967).
3) N. T. Padial and D. W. Norcross: Phys. Rev. A 29,
1742 (1984).
4) M. Kitajima et al.: At. Collision. Res. Jpn. 24, 10(1998) and private communication.
5) M. Kimura: private communication.
6) M. H. F. Bettega et al.: Aust. J. Phys. 53 , 399 (2000).
7) Y. Itikawa: Phys. Rep. 46, 117 (1978).

RI KEN Accel. Prog. Rep. 34 (2001)

Photoabsorption Spectra in the Continuum of Molecules
and Atomic Clusters t
T. Nakatsukasa and K. Yabana*

,,
," ,

Since excitation spectra above the ionization threshold are continuum spectra, it is very important totake into account the effect of the electronic singleparticle continuum. The random-phase approximation(RPA) with Green's function technique 1 ,2) is a powerful method to investigate a continuum response offinite systems to electromagnetic fields. However, theapplicability was rather limited, namely the method
is applicable only to spherical systems. We present
alternative methods based on a theory of the timedependent local density approximation (TDLDA) to
calculate the excitation spectra for systems with arbitrary shape at the RPA level.
The exact treatment of the continuum is represented
by an outgoing asymptotic behavior of the singleparticle Green's functions,C(+)(r, r'; E) = (rl(E - Hsp + iE)-llr'),(1)which appear in the expression of the response (density
correlation) function. Here Hsp is the single-particle
Hamiltonian of the ground-state Kohn-Sham equation.
In order to impose the outgoing boundary condition
upon the Green's function, we utilize an equation forthe single-particle Green's function ,(2)where G~+) is a single-particle Green's function for asolvable Hamiltonian Ho and V = Hsp - Ho. For instance, we may take Ho as a single-particle Hamiltonian with a spherical Coulomb potential. Solving theDyson-type Eq. (2) in a three-dimensional coordinate
space, now we can exactly treat the continuum. See
the paper t for details.
We apply the method to finite electron systems,
e.g. molecules and clusters. We show photoabsorption spectra of valence electrons of ethylene in Fig. 1.
The agreement with experiment is excellent. In thiscalculation, the highest-occupied molecular orbital(HOMO) is found at -11.7 eV. Thus, for w > 11.7 eV,electrons can be excited into the continuum. Whenthe system is polarized by an external electric field,
the induced polarization acts as a screening field.
The dashed line in the figure shows the result of the
independent-particle approximation (IPA) which ignores this dynamical screening. We see that the dielectric effects are essential for reproducing the photoabsorption spectra. We have applied the method toCondensed from the article in J. Chern. Phys. 114, 2550
(2001)
Institute of Physics, University of Tsukuba

Photoabsorption oscillator strengthI' ,': i: :;

I~: ~ ;1\

I

I
,,,
,

"I

,,

v'

l.

:'
"

"
"
"

"
"
"
"

,'

,,, ''""

o ~~J_'~__o10

L -_ _~_ _- L_ _~_ _ _ _~_ _~_ _~

20

30

40

Photon energy w [eV 1

Fig. 1. Photoabsorption spectra of ethylene molecules. The
solid and dashed lines are the calculated spectra withand without a dynamical screening effect, respectively.
The dotted line indicates experimental data.
a negatively charged N a 7 cluster and to other small
molecules, silane and acetylene.
Another method we have developed is a real-time
method. We calculate the time evolution of a TDLDA
state under an external field and demonstrate that thecontinuum effect may be effectively taken into accountby introducing a complex absorbing potential at theedge of the box (R < r < R + ~r). We adopt anabsorbing potential of a linear form,r-R
W(r) = -iWo-~r

for R < r < R + ~r.

(3)

The WKB analysis provides a condition of minimizing
the total reflection,3)
20

E 1/ 2~r

1-j&TI, < IWol < -~rvs;;;,E3/2 ,
8m

10

(4)

where E is the energy of outgoing particles. Advantageof this method over the previous one is the computational feasibility. See the article t for the applicationsof the real-time method and comparison with the previous method.
References
1) S. Shlomo and G. Bertsch: Nucl. Phys. A 243, 507(1975).
2) A. Zangwill and P. Soven: Phys. Rev. A 21,1561 (1980).
3) M. S. Child: Mol. Phys. 72, 89 (1991).

87

RIKEN Accel. Prog. Rep. 34 (2001)

Radiative Electron Capture of Swift Heavy Ions
T. Azuma, T. Ito, Y. Takabayashi, K. Komaki , T. Kambara, Y. Kanai, Y. Nakai, T. Kojima, and Y . Yamazaki
Various kinds of X rays have been observed in heavyion-solid collisions. The characteristic X rays originating either from projectile ions or target atoms are observed as discrete peaks. The X rays with energy distribution much broader than the above, caused throughcollisional dynamics between projectile ions and target atoms, are also observed. The typical examples
are X rays associated with the electron capture into
the discrete states of projectile ions from target atoms
to satisfy both the energy and momentum conservations. This process called "radiative electron capture(REC)" was first observed by Schnopper et al. l ) Since
then a number of experimental REC data have been
accumulated. 2 ) For low energetic projectiles, the REC
process is neglibible compared with the non-radiativeelectron capture process, but it becomes dominant forhigh Z ions at the high incident energies, since REC
cross section is crudely scaled by v;;5 (vp: projectile velocity) in contrast to the non-REC cross section scaledby V;;l1. The energy width of the X-ray peak associated with the REC process originates from the momentum distribution of the bound electrons of the target
atom, i. e., the Compton profile.
In addition these bound electrons have anotherchance of being captured into the continuum statesof projectile ions by emitting photons. This process issometimes called "radiative electron capture into thecontinuum states (RECC)" as an analogy to REC.3 )The RECC process is accompanied by the emission ofcontinuum X rays with a maximum edge energy corresponding to that of electrons with velocity of vp. Electrons once excited into the continuum by the RECC
process have a chance to emerge as a "convoy electron" emitted at the zero-degree direction with velocity around vp .
We investigate these X rays via measurements ofthe energy spectra of emitted X rays at the ion-solid
collisions together with coincident measurements ofcharge-state distribution of emerged projectile ions in
the incident energy range of several tens MeV/nucleon.
Bare Kr 36 + ions of 36 MeV /nucleon passed through a
178 J.Lg/cm 2 -thick carbon foil tilted by 45° from thebeam direction. Emitted X rays at the collisions wereobserved by a Si(Li) detector located at an angle of90° from the beam direction. The charge distribution of emerged projectile ions was measured using a
combination of a magnetic analyzer and position sensitive 2D-silicon detectors at the downstream end of thebeam. The signals from the charge distribution of the
projectile ions and X rays were accumulated in a list
mode.
The X rays emitted from REC into the K- and L-

88

X ray for 36 MeV/u K~6+(b)with coincidence

Energy [keV]

Fig. 1. X-ray energy spectra for 36 MeV/nucleon Kr 36 +ions. (a) Single spectrum. (b) Spectrum taken in coincidence with the component of Kr 35 + after passing
through a 178 J.lg/cm 2 -thick carbon foil. The correction
for the detector efficiencies are not made.

shell, the continuum X rays from RECC , and the characteristic Ka and K,6 X rays of the projectile ions on
the shoulder of the curve for the RECC component
were observed as shown in Fig. 1 (a). The spectrum of
X rays in coincidence with the component of hydrogenlike Kr 35 + among emerged projectile ions, i.e., the electron captured state is also shown in Fig. 1 (b). It isclearly seen that the peaks associated with the electron
capture process are stressed as a result of depression of
RECC and other background component. The characteristic X rays are emitted following capture of target
electrons into the L or higher states of the projectileions. The peak energies for the K- and L-REC components are 37.1 and 23.7keV, respectively. The oberved
energies agree well with the theoretical values expectedfrom the relativistic kinematics, which confirms its validity for the REC process. Furthermore, the observed
energies of Ka and K,6 X rays are 13.5 and 16.0 keV,and are also consistent with the theoretical value.
References
1) H. W. Schnopper et al.: Phys. Rev. Lett. 29, 898 (1972).
2) see references in Th. Stohlker et al.: Phys. Rev. A 51 ,
2098 (1995).
3) H. Tawara et al.: Phys. Rev. A 55, 808 (1997); T.
Ludziejewski et al.: J. Phys. B 31 , 2601 (1998).

RIKEN Accel. Prog. Rep. 34 (2001)

Elastic Wave from Fast Heavy-Ion Irradiation of Metals
T. Kambara, Y. Kanai, T. M. Kojima, Y. Nakai, Y. Yamazaki, A. Yoneda, and K. Kageyama*
We have observed elastic oscillations in the ultrasonic region from various solid samples irradiated witha pulsed ion beam. We have previously reported theexperimental setup at the Ring Cyclotron and the preliminary resultsl) with 26 MeV lu Xe ions as well as theprocedure used to obtain the short pulse beam. 2 )In recent measurements, we have observed a longitudinal wave pulse with a rise time shorter than 70 ns
at the onset of the ultrasonic oscillation for metallic
samples. The samples were polycrystalline Al and eu
plates with square-shaped faces of 35 mm x 35 mm anda thickness of 5 or 10 mm. The ion beam was incident
on one face at right angles with a spot size of about
3 mm x 3 mm and a piezoelectric ultrasonic sensor wasplaced at the opposite side of the beam spot. According to calculations, the range of the ions in Al is estimated to be 280/Lm and that in eu to be 110/Lm.
They are much shorter than the thickness of the samples. Therefore, all the ions were stopped in the material near the incident surface.
Figure 1 shows the ultrasonic waveform from the
5-mm-thick Al sample, along with the microstructureof the beam pulse. The beam spot was at the centerof the face of the sample, immediately opposite thesensor. The displayed waveforms are composed of an
average of 34 shots.
The waveform from the sensor has an oscillatory
structure, as shown in Fig. 1 (a). Figure 1 (b) shows
the onset of the ultrasonic oscillation. At the onset,
there is a low and sharp pulse with a rise time shorter
than 100 ns which is delayed by about 0.8/Ls relative
to the beam pulse. This arrival time is consistent withthat estimated with the tabulated speed of the bulk
longitudinal wave denoted as L in Fig. 1 (b). Therefore, we conclude that the observed ultrasonic pulse isa very short longitudinal wave generated at the timeof irradiation. On the other hand, there is no such
structure evident in the waveform at the expected arrival time of the shear wave. A similar short pulse wasobserved for 10-mm-thick Al and eu samples at the
expected arrival time of the longitudinal wave.
Figure 2 compares the waveforms for a 10-mm-thickAl sample at different beam spot positions; the beam
spot at the center of the face immediately opposite the... ---- sensor (0 mm), shifted from the center by 3 mm, 6 mm
and 12 mm. The onset waveform depends on the position of the beam spot and it gradually becomes broader
as the distance increases. The onset time matches theestimated arrival time of the longitudinal wave denotedby arrows in the figure. We speculate that the increase

Beam Bunch

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c.

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·0.1 !:---'-'--::'=.--'---::'=.-----'---:::'-::---'-----:'
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10
20
30
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0.1 (b)

~
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s

S-

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Ultrasonic Wave

c

<U

C/)

5

-0.14

6

Time (Ils)Fig. 1. Ultrasonic waveform from a sensor on the back of
a 5-mm-thick Al sample, along with the time structureof an ion bunch. (b) is expansion of ( a) near the onsetof oscillation. L denotes the arrival time of the .bulk
longitudinal wave estimated with the tabulated soundvelocity.

0.04

~0.02
E
S-

O
...o

~----~~~~

O~--~~~~~-0.02

<U

C/)

-0.04
4

Time (Ils)Fig. 2. Ultrasonic waveforms for a lO-mm-thick Al sample
at the beam spot on the opposite side of the sensor(Omm) and at 3-12mm from the center. Arrows denotethe estimated arrival time of the longitudinal wave.

of the pulse width is due to the finite size of both thebeam spot and the ultrasonic sensor.
References
1) T. Kambara, Y. Kanai, T. M. Kojima, Y. Nakai, A .
Yoneda, K. Kageyama, and Y. Yamazaki: Nucl. Instrum. Methods Phys. Res. B 164/165, 415 (2000).
2) A. Yoneda and T. Kambara: RIKEN Accel. Prog. Rep.
33, 203 (2000).

Department of Mechanical Engineering, Saitama University

89

RIKEN Accel. Prog. Rep. 34 (2001)

Hardening of Fe-eu Alloys by Swift Heavy Ion Irradiation
T. Hasegawa,*I,*2 A. Iwase,*1 Y. Chimi,*1 N. Ishikawa,*1 T. Tobita,*1
M. Suzuki,*1 S. Ishino, *2 and T. Kambara
As irradiation-enhanced precipitation of copper
atoms in stainless steels causes the hardening and embrittlement of reactor pressure vessels, it is one of
the important phenomena, the understanding of which
provides the basis for nuclear reactor safety. For the
past decade, much work on irradiation enhanced Cu
precipitation in stainless steels and Fe-Cu model alloys
has been carried out by using neutron, electron andlow energy ion irradiations. It is usually assumed thatthe thermal motion of point defects produced throughelastic collisions dominates the phenomenon. Recently,
however, Barbu et al. have shown that in Fe-1.3% Cu
alloys irradiated with 5.1 GeV Kr ions, the electron excitation along the swift ion beam path induces the Cu
precipitation. 1) In this paper, we report the change inhardness of Fe-Cu alloys by Ge V heavy ion irradiation
at elevated temperatures, and compare the results withthose for electron irradiation.
Two model alloys, Fe-0.6% Cu and Fe-1.2% Cu wereused for the present experiment. The specimens were
irradiated with 3.5 GeV (26 MeV lu) Xe ions using the
RIKEN ring cyclotron. The specimen temperatureduring Xe irradiation was kept constant at 250°C. For
comparison, irradiation with 3.8 GeV (21 MeV lu) Ta
ions at room temperature was also performed. After the irradiation, the hardness of the specimen in
the irradiated and unirradiated areas was measured atroom temperature using a Vickers hardness tester witha load of 100 gf.
Figure 1 shows the change in Vickers micro hardness
by irradiation as a function of dpa (the number of displacements per atom by elastic collisions) which is calculated by using the TRIM computer code. 2) In the
figure, the results for 2.5 MeV electron irradiation at
250°C 3 ) and those for the 3.8 GeV Ta irradiation atroom temperature are also plotted. For Fe-1.2% Cu
alloys, the change in hardness due to the Xe irradiation is much greater than that due to electron irra-*1 Japan Atomic Energy Research Institute*2

90

Faculty of Engineering, Tokai University

100

26MeV/u Xee·· ·1.2Cu
0·· ·O.6Cu
2.5MeV Electron••• ·1.2Cu
D·· ·O.6Cu

80

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~ 60

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g

/

C/)
C/)

w

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I

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Oil
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I

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0
10-7

10-6

/1
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10-5

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10-4

10-3

10-2

DOSE, dpa

Fig. 1. Change in Vickers microhardness of Fe-Cu alloys
by Ge V ion and electron irradiations as a function of
calculated dpa.

diation at the same dpa value, while for Fe-0.6% Cu
alloys, the change in hardness is smaller than that forFe-1.2% Cu. The figure also shows that Ta irradiation
at room temperature rarely changes the hardness of
Fe-Cu alloys. The present result implies that the electronic excitation by GeV heavy ions contributes to theprecipitation of Cu atoms, which causes the increasein hardness. The extent of the contribution depends
on the concentration of Cu atoms and the irradiation
temperature.
References
1) A. Barbu et al.: Nucl. Instrum. Methods Phys. Res. B
146, 278 (1998).
2) J. P. Biersack et al.: Nucl. Instrum. Methods B 174,257 (1980).
3) T. Tobita et al.: Trans. 15th Int. ConE. on Structural
Mechanics in Reactor Technology (SMiRT-15) X-205(1999) .

RIKEN Accel. Prog. Rep. 34 (2001)

Magnetic Properties of Fe-Ni Invar Alloys Irradiatedby High-Energy Heavy Ions
F. Ono,*1 A. Takahashi,*1 S. Wei,*1 H. Inoue,*1 A. Iwase,*2 Y. Chimi,*2
N. Ishikawa,*2 N. Kuroda,*2 and T. Kambara
Fe-Ni alloys around the Invar composition of 35 at. %Ni show various anomalies in both mechanical andmagnetic properties. Anomalies in the physical properties such as low thermal expansion were interpreted
as being due to the large positive value of the magnetovolume effect which cancels out the normal part of thethermal expansion. Anomalies in the magnetic properties are an unusual decrease in the spontaneous magnetization from the Slater-Poling curve and an abrupt
increase in the high-field susceptibility.
These anomalies have been understood from theband picture to be a result of the instability of the 3dband electron ferromagnetism. 1) However, the detailed
concentration dependence of the magnetization cannot
be explained without taking into account the effect of
the concentration fluctuation , as pointed out by Kachi
et al. 2 ) The extent of the concentration fluctuation in
Fe-Ni Invar alloys made by the conventional alloying
method was estimated by adjusting the Gaussian distribution parameter to fit the experimental curve. Using this parameter, magnetic anomalies in Fe-Ni Invar
alloys have been explained satisfactorily. Thus, theconcentration fluctuation was found to play an important role in the fabrication of Fe-Ni Invar alloys.
We have succeeded in changing the extent of the concentration fluctuation by mixing the powders of thestarting elements and mechanically alloying 3 ) them.
The extent of the fluctuation was controlled by annealing the alloys at high temperatures. 4 )The effect of high-energy ion beam irradiation on themagnetization curves of the mechanically alloyed Fe-Ni
Invar was investigated using a sample-subtracting-typemagnetometer. The irradiations were carried out using 2.86 GeV Xe ions at a fluency of 10 12 /cm 2 using
the RIKEN Ring Cyclotron. The observed magnetization curves at room temperature before and after theirradiations are shown in Fig. 1. The magnetization
for all the samples with different extents of fluctuation
decreased upon irradiation. However, the irradiation

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e ann., irradiatede annealedo 500°Cann.,irradiated
I

I

I

0.5

1

1.5

H (T)
Fig. 1. Magnetization curves for Fe-Ni Invar mechanicalalloys at room temperature before and after high-energy
ion irradiation.

effect is the smallest in the three samples at the moderate extent of concentration fluctuation, i.e. , annealed
at 800°C. This tendency may be associated with otherunique characteristics of this extent of fluctuation asshown in Ref. 4.
References
1) P . Entel et al.: Phys. Rev. B 47, 8706 (1993).
2) S. Kachi et al.: J. Phys. Soc. Jpn. 25, 285 (1968).
3) F. Ono et al.: Proc. '98 Powder Metallurgy World Congress, Granada, Spain, Vol. 1 (1998) , p. 449.
4) S. Wei et al.: J. Magn. Soc. Jpn. 23 , 391 (1999).

Department of Physics, Okayama University
Japan Atomic Energy Research Institute91

RIKEN Accel. Prog. Rep. 34 (2001)

Magnetic Relaxation In Bi-2223 Tapes Irradiated by Xe Ions
H. Ikeda, N. Ishikawa, A. Iwase, T. Kambara, and R. Yoshizaki*
In the field of power applications it is necessary
to fabricate superconducting materials with high critical current densities J e . Higher J e is, in general,
achieved by increasing in the flux pinning energy in superconductors. However, in the high-temperature (Te)cuprate superconductors, the large flux creep effect inthe magnetization has been reported. 1) Therefore, wehave to clarify the origin of the pinning mechanism
in high-Te superconductors. As a first step, we introduced columnar defects in to the Bi-2223 tapes parallelto the aligned c-axis (normal to the tape surface) by
Xe-ion irradiation and measured the distribution of theflux pinning energy.2) In the present research, we study
the pinning energy distribution for the Bi-2223 tapeswith columnar defects by Xe-ion irradiation.
The Ag-Cu alloy sheathed tapes were prepared by
the powder-in-tube method. The details of the preparation method and the fundamental properties of thesamples were reported elsewhere. 3 ) Bi-2223 tapes with
3.0 x 3.0 x 0.1 mm3 typical dimensions were irradiated with 3.5 GeV 163Xe31+ ion at the RIKEN Ring
Cyclotron Facility to introduce columnar defects perpendicular to the tape surface direction. The magnetic properties were measured using a superconducting quantum interference device (SQUID) magnetometer. Pinning potentials were estimated from the decay profiles of the remanent magnetic moment for thenonirradiated and irradiated Bi-2223 tape samples.
In the magnetic relaxation measurement, we adopted
the following process: the magnetic field was initialized to zero (approximately 20 p,T), then the sample
was loaded at the measurement temperature. Afterthe zero-field cooling, a magnetic field was applied(H = 1 T) and the relaxation of the magnetization
was measured for approximately 105 sec.
The relaxation of the remanent moment for the irradiated and nonirradiated samples shows the linear In(t)dependence in the entire observed temperature range.
In order to study the effects of temperature and irradiation on flux creep, the magnetization M is normalized
to the initial magnetization Mo. It is clearly seen thatthe slope of M/Mo versus In(t) decreases the relaxation
rate for the irradiated Bi-2223 tape samples. This result shows that the critical current density (Je ) can be
improved in the entire temperature range with irradiation. The standard model for flux creep in superconductors proposed by Anderson 4) has been used to analyze data on high-temperature superconductors. We
use the model of Maley et al. 5 ) to analyze the data. Using the rate equation of Beasley, Labusch and Webb: 6)
dM/dt = (Bwa/,rrd) exp( -UejJ /kT), where wand a
Institute of Materials Science, University of Tsukuba

92

Bi-2223 Tape
H//c

0.20

H=l T

o (a) C=20(b) C=25~ 0. 15~ 0.10
Q)
~

0.05

o. o~

50

100

150

- (M-Meq)

200

250

300

350

(emu/cm 3)

Fig. 1. The effective pinning potential U ejf as obtained
from the nonlinear equations for flux creep versus themagnetization M for the irradiated Bi-2223 tape andthe nonirradiated ones.

are the hop frequency and distance, respectively, for aflux bundle, and d is the grain diameter. This leads tothe expression UejJ/k = -T[ln(dM/dt) -In(Bwalrrd)]
for the effective pinning potential. Here, we have estimated the value of the constant C = In(Bwalrrd)
empirically by plotting the data as UejJ / k versus M ateach temperature for the irradiated and nonirradiatedBi-2223 tape samples and adjusting C to obtain thesmoothest curve. The constant values are C = 20 for
the irradiated case and C = 25 for the nonirradiatedones, as shown in Fig. 1 (a) and (b). These values imply physically reasonable values. It is considered thatthe difference in C behavior between the irradiated andnonirradiated cases comes from the difference in the induced defect structure with irradiation. In the case ofirradiation, it produces columnar defects (amorphoustracks with diameters of ~ 6 nm), which yield a large
pinning energy of high-temperature superconductors
for vortices parallel to the defects.
We observed the pinning energy distribution for the
Bi-2223 tape samples. We used Maley's expression
to analyze the data. The change in the distributionof the activation energies with irradiation was determined. Since the number of deeper pinning centers asincreased, it is expected that the columnar defects will
act as effective pinning centers.
References
1)
2)
3)
4)
5)
6)

K. A. Muller et al.: Phys. Rev. Lett. 58, 1143 (1987).
H. Ikeda et al.: Physica B 284/288, 871 (2000).
M. Ishizuka et al.: Physica C 252 , 339 (1995).
P. W. Anderson: Phys. Rev. Lett. 9 , 293 (1972).
M. P. Maley et al.: Phys. Rev. B 42, 2639 (1990).
M. R. Beasley et al.: Phys. Rev. A 181, 682 (1969).

RIKEN Accel. Prog. Rep. 34 (2001)

Scaling of Irradiation Effects by Primary Ionization Rate in
Ion-Irradiated Oxide Superconductors
N. Ishikawa, Y. Chimi, A. Iwase, O. Michikami,* H. Wakana,* and T. Kambara
It is customary to analyze the effect of electronic
excitation in terms of the electronic stopping power,
Se, which is defined as the energy transferred fromincident ions to electrons of the target per unit ionpath length. 1 ,2) However, in the present study, we
have found that the defect production via electronic
excitation in ion-irradiated oxide superconductors isdominated by the primary ionization rate rather thanthe electronic stopping power.
Thin films of an
EuBa2CU30y (EBCO) oxide superconductor were irradiated with various heavy ions (120 MeV el, 150 MeV
Sc, 90 MeV Ni, 125 MeV Br, 0.71 GeV Kr, 90 MeV I,
3.54 GeV Xe, 3.84 GeV Ta, and 200 MeV Au) in a wide
energy range of 90 MeV- 3.84 GeV. The ions with theenergy of 90- 200 MeV were produced at a tandem accelerator at Japan Atomic Energy Research Institute,
Tokai Establishment (JAERI-Tokai) , and the ions of
0.71- 3.84 GeV were produced at the RIKEN Ring Cyclotron. All irradiations were performed at a fixed
temperature of 100 K. The values of !:::.p/ Po were measured in situ as a function of ion fiuence , <1> , at 100 K
by the standard four-probe method , where !:::.p/ Po isthe change in resistivity normalized by the resistivity
before irradiation, Po.
An increase in normal-state resistivity and a decrease in superconducting transition temperature, T e ,are observed for all irradiations, indicating that lattice defects are introduced by the irradiations. In
Fig. 1, it is found that the initial slope of the resistivity change, [(!:::.p/ Po)/<I>] <I>-->O , can be well scaled by
the primary ionization rate. The primary ionization
rate is represented by dJ / dx , where J is the numberof target atoms primarily ionized by the irradiating
ion and x is the path length of the irradiating ion. 3,4)
In Fig. 2, it is also found that the change rate in T e ,(!:::.Te/Teo) / <l>total, is well scaled by the primary ionization rate. Here, Teo is the value of Te before irradiation,<l>total is the fluence at which the resistivity at 100 K
becomes 2.4 times larger than that before irradiation,
and !:::.Te = Teo-Te (<I> = <l>totaz).
In our previous study,5) it was found that electronic
stopping power is not an appropriate parameter fordescribing the defect production process in EBCO irradiated with high-energy heavy ions. From these results, it is concluded that the primary ionization rate
is a much better parameter than the electronic stopping power for describing the defect production process. This is consistent with the results of our previ-e90-200MeV 10
OGeVlonCI

0.0 0.5 1.0 1.5 2.0
dJ/dx (arb. units)
Fig. 1. [(llp/ Po)/<p]<I>-+o plotted as a function of the primary ionization rate.
,,-..,

10- 12 ,.....--_--.-_ _...--_----,
90-200MeV on'-'
0 GeV Ion

N d

5

e

Ni

Xoo
Sc
~ u 10-15 I...-...L----L.._ _....1....._---I
<]
'-'

0.0

0.5

1.0

1.5

dJ/dx (arb. units)

Fig. 2. (llTc/Tco )/<Ptotal plotted as a function of the primary ionization rate.

ous study of lattice parameter changes in ion-irradiated
EBCO.6) Successful scaling of the irradiation effects by
the primary ionization rate suggests that the atomic
displacements are triggered by Coulomb repulsion between primarily ionized atoms.
References
1) V. Hardy et al.: N ucl. Instrum. Methods Phys. Res. B

54, 472 (1991).
2) Y. Zhu et al.: Phys. Rev. B 48, 6436 (1993).
3) H. A. Bethe: Ann. Phys. 5 , 325 (1930).
4) R. L. Fleischer et al.: Phys. Rev. 156, 353 (1967).

5) N. Ishikawa et al.: RIKEN Accel. Prog. Rep. 32 , 99
(1999) .
6) N. Ishikawa et al.: Nucl. Instrum. Methods Phys. Res.
B 135, 184 (1998).

Faculty of Engineering, Iwate University

93

RIKEN Accel. Prog. Rep. 34 (2001)

In-Beam Mossbauer Study on the Jump Mechanism of
Self-Interstitials in Pure Iron
Y. Yoshida, *1 Y. Kobayashi, F. Ambe, E. Yagi, X. Diao, and A. Seeger*2
The jump mechanism of self-interstitials in bodycentred cubic metals is still only partially understood.
Direct observations of self-interstitials are highly desirable in order to clarify the jump processes on an
atomistic scale. In-beam Mossbauer spectroscopy using the 56Fe( d,p )5 7Fe reaction offers the possibility
to study the motion of self-interstitials in iron crystals. By the 56Fe( d,p )57Fe* reaction, 57Fe probes excited to the 14.4 ke V level (denoted by 57Fe*, lifetime
9
TM6ss = 140 X 10- s) are produced in natural Fe
and ejected from their lattice sites approximately inthe beam direction with kinetic energies up to about
1 MeV. A certain fraction of the ejected 57Fe* probes
end up as self-interstitials in the Fe matrix. Information on the jump vectors of the interstitial 57Fe*
may be obtained by measuring the dependence of the
Mossbauer spectrum on the crystal orientation.
A single-bunch 8 MeV deuteron beam with repetition period 1.2 j..lS, pulse width 2 ns, and cross section
3 mm x 10 mm was used to implant the 57Fe* nuclei
into an Fe single crystal. The time window was set at
100 to 500 ns , thus suppressing background counts due
to short-lived reaction products. The beam current
was 75 or 110 nA, corresponding to fluxes of 1.8 x 10 12
or 2.8 x 10 12 deuterons/(cm 2·s). High-purity Fe single crystals of 5 mm x 12 mm x 1 mm prepared at the
Max-Planck-Institut fiir Metallforschung by strain annealing were chemically etched down to thicknesses of
50 j..lm and finally purified by anneals for 24 hours at
1123 K under wet H2 gas and for 24 hours at 923 K
under dry H2 gas. The thickness of the samples guaranteed that virtually no deuterons were stopped in thesample. The orientation of the crystal foil mounted
on a sample holder was checked by the Laue method.
The deuteron beam direction was 10° from [11 0]. For
measurements between 300 and 700 K an infrared lamp
heater is used. The vacuum in the chamber was kept
at about 10- 5 Pa throughout the measurements. A
parallel-plate avalanche counter (PPAC) detecting theconversion electrons emitted from the Mossbauer absorber is mounted on a Mossbauer transducer. At a detector distance of 0.07 m, typical 14.4 keV , -ray countrates were about 12 S - l for currents of 75 nA. At a
distance of 0.11 m the angular resolution was 5° .
Typical in-beam spectra measured at different temperatures between 150 and 700 K in the [1 00] direction
are shown in Fig. 1. Figure 2 compares the fit parameters, namely (a) total area A, (b) hyperfine field B hf ,(c) centre shift <5 and (d) full width at half maximum r*1 Shizuoka Institute of Science and Technology*2 Max-Planck-Institut fur Metallforschung, Germany

94

-8

-6

-4

-2

o

2

4

Velocity (mm/s)
Fig. 1. In-beam Mossbauer spectra of a -Fe between 150
and 700 K measured in [100] at a detector distance of
0.07 m. The 150 K spectrum was obtained in an earlier
experiment under otherwise similar conditions.

(full symbols), with those obtained in a conventional
laboratory experiment on pure Fe in ultra-high vacuum (open symbols). None of the spectra of Fig. 1
show well-resolved satellite lines. Although at a firstglance the spectra appear to be very similar to those of
unirradiated Fe, the temperature dependences of the
fit parameters are quite different, as may be seen in
Fig. 2: (a) The area A decreases much faster than expected from a Debye model with the Debye temperature BD = 470 K of unirradiated Fe. (b) The hyperfine
fields Bhf are lower than those of unirradiated Fe. (c)Above 550 K the centre shift Q starts deviating fromthe second-order Doppler shift corresponding to substitutional Fe. (d) The full widthof the Mossbauerline at half maximum stays at a constant of about
0.40 mms- 1. The spectra at 500 K were also measured
along the measuring directions of 0° (= [100]) , 14°,22°, 32° and 45° (= [110]) in the (001) plane. The
fit parameters depend strongly on the measuring directions. The facts that Bhf and <5 do depend on theemission directions and that a peak is superimposedon the gradual decrease of A with increasing (), show

r:

o.~
~ 0.6

•

0.45
'-;"00+0.40

E.§ 0.35
l.,

0.30
200

•

•

•

0

References,f ++,+
T+

that the spectra at elevated temperatures arise fromthe superposition of several 6-line components. If thespectra consisted of the substitutional Fe component
only, the area would show a simple "cos () effect" due toMossbauer self-absorption, and both the hyperfine field
and the centre shift would not change at all. Nevert heless, the data analysis in terms of A, Bhf, r, and <5 wasbased on one 6-line set only; hence the numerical values must be considered motionally averaged over different contributions to the spectra. The observations
will allow us to study the jumps of 57Fe* on non-latticesites on the time scale 10- 7 s by comparing the angulardependence of the area with those predicted from different jump models, such as dumb-bell and crowdion
models. l )1) H. J. Blythe, H. Kronmiiller, A. Seeger, and F. Walz:
Phys. Stat. Sol. (a) 181, 233 (2000).

T

(d)
I

300

I

I

I

400 500 600
Temperature (K)

700

800

Fig. 2. Temperature dependence of the fit parameters
above 300K; (a) area A, (b) hyperfine field Ehf, (c)centre shift 8, and (d) full width at half maximum r.
Open symbols refer to the control experiment.

95

RIKEN Accel. Prog. Rep. 34 (2001)

In-Beam Mossbauer Study on Interstitial and Substitut ional
57Mn/57Fe Jumps in Si
Y. Yoshida,* Y. Kobayashi, K. Hayakawa,* K. Yukihira,* F. Shimura,* A. Yoshida,
X. Diao, H. Ogawa, Y. Yano , and F. Ambe
Iron is known to be a fast diffusing impurity in
Si, and the diffusion is thought to proceed via interstitial sites. However, no direct observation of thejump processes has been achieved at high temperatures. Mossbauer spectroscopy is expected to give us
information not only on the lattice sites, but also on
the jumping processes of the probe atoms in the material. In order to study the diffusion processes of isolated Fe in Si, there is an experimental difficulty, i. e.,an extremely low solubility of 57Fe in Si. For such alow concentration there has not been a measurement
particularly with Mossbauer spectroscopy at high temperatures. In order to pursue a Mossbauer experimentwith low concentration of 1011 Fe/cm 3 in Si wafers ,we have developed a new experimental technique ofMossbauer spectroscopy using an on-line isotope separator for projectile nuclear fragments at the RIKEN.
This method provides a possibility for direct observation of the diffusion processes of Fe atoms in bulk Si
crystals at the atomic scale. The on-line isotope separator (RIPS) produces a radioactive beam of 57Mn,
which decays with a half-life of 1.45 min to the 14.4ke V Mossbauer level of 57Fe*. Accordingly, the highly
energetic particles with several GeV from the separator
can be implanted directly into the depth range of several hundred /-lm from the surface. Subsequently, the14.4keV ,-rays emitted from 57Fe* provide a possibility to measure Mossbauer spectra, which give atomistic information on both the local surrounding andthe dynamics of the 57Fe* atoms at the final latticesites through hyperfine interactions .
Figure 1 shows the Mossbauer spectra of 57Fe* following the decays from 57Mn implanted into FZ-(l11)
Si. The spectra were measured between 350 and 650 K.
The spectrum at 350 K can be fitted by two components corresponding to interstitial Fe on the left-handside (8 = . 0.76(2) mms- 1 ) and substitutional Fe on
the right-hand side (8 = 0.02(5) mms- 1 ) . The similar
spectra were observed below 300 K in the former experiment on FZ-(100)Si.l) The isomer shifts of both interstitial and substitutional lines are in good agreementwith those obtained from theoretical calculations.2 ) In
Fig. 2, the fit parameters are shown as functions oftemperature: The total area A (a), the interstitial fraction Fint (b) and the centre shifts 8 of both components(c). The lines drawn in Fig. 2 (a) and (b) are only foreye-guide. The dotted line in Fig. 2 (a) corresponds tothe temperature dependence predicted from a DebyeShizuoka Institute of Science and Technology•
96

57MnJ57

no~105

Fe in FZ-Si(111)
i

I

1

100

::: ~

1

100

CIJ
......

~ ::: [-; 100
S

~

A.

.. .~

~

~ ::: [
100 ~

no!

105

475K

1.

~.¥.~
........ ..•.. '.
. .•.•-. .' .

. .
•

•• '

•

~.

.. .

425 K

'.

,
....

• ••••• ••..... - •• .. ~••• ' "

'0'

.'0

~
'
.
. '. .'
"

•

350 K

. .,

......

1~

1
1

100 L-~-L'________________':~:_·'~__~~~:_~~·_:_···~._·~";_.~~_
-3

-2

-1

o

Velocity / mms·lFig. 1. Mossbauer spectra of 57Mnj57Fe* in FZ-(111)Si
measured between 350 and 650 K ,model with a Debye-temperature of 450 K , which isdeduced from the Debye-temperature of Si, 640 K , bytaking into account the mass difference . The data
points of the total area deviate from the course of the
Debye model, which may be related either with an anharmonic effect or with a fast jump process of Fe atoms
in Si. The temperature dependence of the centre shift
mainly originates from the second-order Doppler shiftplotted between the data points in Fig. 2 (c), whichis essentially a measure of the mean square velocityof 5 7Fe* in the Si matrix. The fact that the centre
shifts follow the second-order Doppler shift, indicatethat both interstitial and substitutional components
are well defined up to 600 K. The fraction of the interstitial component, however, starts decreasing at about
500 K , suggesting that the substitutional 57Mn/ 57 Fe*
atoms are created by a reaction with other defects.
Above 500 K there exist line broadenings on both components, which finally merge into a broad single line at
700 K , i.e., a motional averaging due to a 57Fe* jumpprocess. Using the centre shift value, the average occupation probabilities of Fe atoms at 700 K can be es-

0.1
(a)
<:\I
~

100

<
~Q

Eo-;

0.01
1.0
(b)

0.8
0.6
t..,;=

0.4
0.2

.,

0.0
0.5

E
E

0.0

III

~

(c)

!

,

!

.:::

:c -0.5

r.n~!:= -1.0

•

~

u

-1.5
0

100

200

300

400

500

600

700

Temperature / K'

timated to be 30% on the interstitial site and 70% on
the substitutional site.
The defect distributions and the related nm-scale
structures of the samples , which were used in thepresent experiments, have been studied using atomic
force microscopy (AFM):3) Two types of the swellings
were clearly observed on cleaved Si surfaces, which correspond to defects produced by the slowing-down process of 57Mn probes.
Recently, an ISOLDE group4) has measured the inbeam Mossbauer spectra of 57Mn/57Fe in Si after the
implantation with a rather low energy of 60 keY. Theyuse proton-induced fission at ISOLDE on-line mass
separator at CERN. Their results are rather different from the present ones, which may arise from thedifferent implantation energy.
References
1) K. Kobayashi, Y. Yoshida et al.: Hyperfine Interact.
126, 417 (2000).
2) J. Kiibler, A. E. Kumm, H. Overhof et al.: Z. Phys. B
92 , 155 (1993).
3) x. Diao, Y. Yoshida et al.: RIKEN Accel. Prog. Rep.
33, 94 (2000).
4) G. Weyer: private communication

Fig. 2. Temperature dependence of the fit parameters. (a)Total Area A, (b) interstitial fraction Pint, and (c) centre shift. Circle and triangular symbols refer to theinterstitial and substitutional Fe, respectively.

97

RI K EN Accel. Prog. Rep. 34 (2001)

Depth Profile of Vacancy-Oxygen Pairs in CZ-Si
Irradiated with 3.5 GeV-Xe Ions
X. Diao, K. Hayakawa,*l F. Shimura,*l A. Iwase,*2 T. Kambara, and Y. Yoshida*l
In order to determine the effects of GeV ion irradiation on single-crystal silicon, 3.5 GeV-Xe ion irradiation was performed at room temperature using
the RIKEN Ring Cyclotron.!) For the first time, it
was found that vacancy-oxygen pairs are produced in
Czochralski-grown (CZ) silicon by GeV ion irradiation.
Further studies were carried out and a clear depth profile of vacancy-oxygen pairs along the Xe ion trajectoryis described here together with results of the quantitative analysis of defect concentration.
Figure 1 shows the depth profile of IR spectra of theirradiated CZ-Si recorded with a J asco WS /IR-8000
Micro infrared spectrometer at room temperature. It
is known that the two peaks in the spectra, one at
1107 cm- 1 and another at 830 cm- 1 , represent interstitial oxygen and vacancy-oxygen pairs, respectively.
In order to evaluate the concentrations of interstitialoxygen, [Od, and vacancy-oxygen pairs, [VO], conversion factors of f[Od = 3.14 x 10 17 cm- 2 for rOd , andf [vo] = 6.1 x 10 16 cm- 2 for [VOl were used according
to Bullis 2) and Oates and Newman .3 )Since each spectrum in the depth profile (Fig. 1) was
measured from a very thin irradiated layer at a certain depth (20 Mm) , both VO and interstitial oxygen
are assumed distributing homogenously in this layer.
Therefore, local concentrations of [VOl and rOd along
the irradiation depth are obtained based on the spectra. The results are shown in Fig. 2. For comparison,
calculated depth dependence, using program TRIM,of energy loss of Xe ions caused by electronic excitation , Se, and nuclear collision, Sn, is also plotted inFig. 2. The results show very good agreement among
the depth dependences of [VO], rOd and the energy

1200

1100

1000

900

800

Wavenumber (cm-')

Fig. 1. Infrared absorption spectra of irradiated CZSi along the irradiation depth (Fluence = 1.0 x
10 13 Xe/cm 2 ).
*1

Shizuoka Institute of Science and Technology*2 Japan Atomic Energy Research Institute98

15
S.(X50)~~.Q §1O
fj»

~~ 5

w

'7~

0
0.6

+'\

+ +

E
,;°0.4
~
0.2

1+*~f

5=

>

~

0.0

+

+t

t+~~ rf

10.0"IE 9.5
°
';0
9.0

fl

;:;_ 8.5
0
~ 8.0
0

100

200

300

400

500

Depth (!lm)

Fig. 2. Depth dependences of [VOl and rOd in irradiated CZ-Si (Fluence = 1.0 x 10 13 Xe/cm 2 ), and TRIMcalculated energy loss by electronic excitation, Se, andnuclear collision, Sn, respectively.

loss of Xe ions. Apparently, the VO complexes wereformed through consumption of the original interstitialoxygen; which is clearly observed from the decrease in
rOd shown in Fig. 2. However the consumption is notquantitatively equivalent to the VO formation , particularly at the depth where [VOl appears at a maximum
and [Oil at a minimum. It may be concluded that, at
most , 70% of the lost interstitial oxygen atoms havetransferred to VO complexes at such a depth; the remaining 30% probably formed other kinds of defects,
which could not be detected in our experiment. An
interesting argument arises on the grounds that theinterstitial oxygen decreased much more rapidly in thedepth region of 275- 340 p,m than in any other region.
This indicates that the undetected defects are mainly
distributed in this region. On the other hand, theTRIM calculation predicts that the irradiated Xe ionshave completely stopped at the depth of approximately
330 Mm, but the VO complexes are still obviously detectable to a depth of 375 Mm. We may also conclude
from our results that both electronic excitation and nuclear collision contribute to VO formation, each of theircontributions being predominant within their own regions.
References
1) X. Diao, Y. Yoshida, K. Hayakawa, F. Shimura, T .
Kambara, A. Iwase, and Y . Yano: RIKEN Accel. Prog.
Rep. 33, 90 (2000).
2) W. M. Bullis: in Oxygen in Silicon, edited by F.
Shimura (Academic Press, 1997) , p. 100.
3) A. S. Oates and R. C. Newman: Appl. Phys. Lett. 49,
262 (1986).

RIKEN Accel. Prog. Rep. 34 (2001)

Defects and Their Distribution in Si Producedby GeV- 57 Mn Irradiation
X. Diao, K. Hayakawa,* Y. Kobayashi, F. Shimura,* and Y. Yoshida*
At the RIKEN RI-beam factory, GeV-ion irradiation is essential for introducing radioactive isotopes
into materials for materials science research, and therefore it is very important to understand the defects andtheir distributions around the isotopes. We reported
in the last progress report l ,2) that vacancies and otherkinds of defects were produced along ion tracks in silicon upon GeV-heavy-ion irradiation. Although the defects are assumed to be created through both electronic
excitation and nuclear collisions, the formation mechanisms of the defects have yet to be understood thus
far. In the present experiment, after the irradiation of
floating-zone silicon (FZ-Si) with GeV- 57 Mn which was
separated using the RIKEN projectile-fragment separator (RIPS) , the defects and their distribution were
further studied by X-ray diffraction (XRD) and atomic
force microscopy (AFM).
At the E6-beam line of the RIKEN ring cyclotron, an
FZ-Si sample was irradiated with 57Mn. The primaryenergy after the separation was approximately 1 GeV.
In order to stop the ions in the sample, a 470-p,m-thickAl plate was used as an energy degrader. The irradiation was performed at temperatures between 77 and
3000K. The total fluence of 57Mn was 5.0 x 10 l0 /cm 2 .
The incident ion direction was 45° from [110] .
After the irradiation, the back of the Si surface wasmechanically polished and measured using CuK a Xrays in reflection geometry by four-axis XRD. The
beam was 0.5 mm in diameter. The surface was covered with a 2-mm-wide aluminum aperture as shownin Fig. 1. By shifting the position of the aperture,
we were able to obtain XRD patterns at different positions, which may provide information on the latticedefects produced at different depths from the irradiated surface. An obvious split was found at the Si(400) peak, as shown in Fig. 2, for the position corresponding to the depth of 90 p,m , i. e., the ion range of
57Mn.
Furthermore, AFM observations were carried out
on the same area where the X-ray measurement was
performed. In order to obtain a clean and smoothcross section for the observations, the sample was initially cleaved and immediately set into an AFM vacuum chamber. Many hillocks can be observed in theregion from the surface to the ion range of approximately 90 p,m (Fig. 3). In particular, the number of thehillocks increases around the ion range. Accordingly,
the peak shift of (400) observed in the X-ray measurement can be closely related to the lattice defects proShizuoka Institute of Science and Technology

Fig. 1. Schematic view of the experimental arrangement of
XRD.

3.7 3.8 3.9 4.0 4.1 4.2 4.3
hFig. 2. X-ray diffraction patterns of FZ-Si irradiated with
57Mn. The h-scan was performed from (3.700) to(4.300).

Fig. 3. AFM image observed on a cleaved cross section of
FZ-Si irradiated with 57 Mn.

duced around the ion range. Both experiments are stillin progress and the results will be reported elsewhere.
References
1) X. Diao, Y. Yoshida, K. Hayakawa, F. Shimura, T.
Kambara, A . Iwase , and Y. Yano: RIKEN Accel. Prog.
Rep. 33, 90 (2000).
2) Y. Yoshida, Y. Kobayashi , X . Diao, K. Hayakawa, K.
Yukihira, F . Shimura, A. Yoshida, Y . Watanabe , F.
Ambe, and Y. Yano: RIKEN Accel. Prog. Rep . 33, 93(2000).

99

RIKEN Accel. Prog. Rep. 34 (2001)

Surface Modification on Fe-Ni (31.7at.% Ni)
by 3.5 GeV Xe Ion Irradiation
X. Diao, K. Hayakawa,*l A. Iwase,*2 T. Kambara, Y. Yamazaki, and Y. Yoshida*l
Irradiation-effect studies of metallic materials began in the early 1950's, stimulated by the advancement of the nuclear industry. The main problems
concerned with irradiation effects on metals and alloys are changes in mechanical properties, volume andshape changes, and changes in corrosion resistance.
For GeV ion irradiation, only in few materials, e.g., NiZr alloy,l) have irradiation tracks been found, while inother materials, obvious defects induced by irradiation
have never been found. In our experiment, room temperature irradiation on Fe-Ni alloys with 31.7at.% Niconcentration were performed using the RIKEN Ring
Cyclotron with 3.5 GeV Xe ions. Off-line observations
were carried out using X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM), atomic force
microscope (AFM), and Mossbauer spectroscopy.
Three foils of Fe-Ni (31.7at.%) with a thickness of
50.4 11m were overlapped and irradiated successively by
3.5 GeV Xe ions . It is predicted, according to simulation program TRIM, that the Xe ions pass throughthe first two specimens and stop inside the third one.
Therefore, all the measurements were taken on bothsides of each specimen except for the Mossbauer spectroscopy measurement, in which the spectra obtained
show results from the entire body of each specimen.
SEM results show marked differences before and after irradiation. (1) Morphological structures of thesurfaces have been greatly modified by irradiation, except that the back of No.3 remains roughly the same asthat of the original structure, which corresponds to theprediction based on irradiation depth. (2) Bumps andholes are found scattered on the irradiated surfaces andthe boundaries of crystal grains are not distinct after
irradiation.
Two of the AFM images of the irradiated surface
are shown in Fig. 1. The shapes of the bumps arecraterlike, indicating that thermal spikes were formed
during irradiation. These bumps are distributed heterogeneously on the irradiated surfaces with diametersfrom 100 nanometers to 2 microns.
XRD results confirm that all three specimens retain
their f.c.c. crystal structure after irradiation. However, two obvious modifications on the surfaces havebeen observed. (1) Crystalline reorientation of latticedirections is observed. The relative ratios among t heintensities of diffraction peaks from different lattice indices are significantly changed by the irradiation. The
effect appears to be that of recrystallization by heat
treatment. (2) Individual peak shifts and splitting are
*1

*2

100

Shizuoka Institute of Science and Technology
Japan Atomic Energy Research InstituteFig. 1. AFM images of surface of an Fe-Ni (31.7at.%) specimen irradiated with 3.5 GeV Xe ions.

No.1 front

No.1 backNo.2 front
NO.3 front(200)

Nonirrad.

50.4 50.6 50.8 51 .0 51.2 51.4
26(°)

Fig. 2. (200) peaks from XRD patterns of the irradiatedand nonirradiated Fe-Ni specimens.

observed after irradiation (Fig. 2). This reveals slightchanges in lattice parameters and defects produced byirradiation.
Mossbauer spectra did not show apparent changes asa result of irradiation. The average hyperfine magnetic
field has a slight increase compared with that of thenonirradiated Fe-Ni (31.7at.%) alloy.
References
1) A. Barbu, A. Dunlop, A. H. Duparc, G. Jaskierowicz,
and N. Lorenzelli: Nucl. Instrum. Methods Phys. Res.
B 145 , 354 (1998).

RIKEN Accel. Prog. Rep. 34 (2001)

Calibration of a Light Particle Telescope for the ALOS Satellite
Using a 4He Beam
H. Matsumoto ,* T. Goka,* H. Koshiishi,* and H. Katoh
The Advance Land Observation Satellite (ALOS)
will be launched by N ASDA into a sun-synchronous
orbit in 2003. A light particle telescope (LPT) will beon board this satellite to observe high-energy electrons(0.1- 2.9 MeV), protons (1.6- 250 MeV), deuterons(7.1- 27.9 MeV) , tritons (8.3- 28.5 MeV) , 3He (19.3102 .4 MeV) and 4He (9 .1- 300 MeV) ions in the innerradiation belt. The LPT consists of a 0.25-mm-thick
PIN-type detector for measuring flE and four 1.5-mmthick PIN-type detectors for measuring E. In additions to these thick detectors, a 1.5-mm-thick PIN-type
detector is set for use as an anticoincidence detector
to eliminate the signals of high-energy particles which
penetrate the detector stack. The side of the detector stack is covered by high-Z (tantalum) shielding,which excludes side-penetrating protons up to about
100 MeV. A thin aluminum (0.025mm thick) window
is used to stop photons and charged particles with energy lower than the lower limit of the energy measurement.
Signals from the flE and E detectors are pulseheight analyzed simultaneously by fast analog-todigital converters. A logical analysis of the pulses by
the coincidence/anticoincidence circui tty distinguishes
electrons from alpha particles and accumulates pulseheight distributions in the memory.
The telescope was tested and calibrated at the E3
target room of the RIKEN ring cyclotron. A 4He beamwith an energy of 135 MeV /nucleon was used to measure the fundamental characteristics of the PIN-type
detectors used in the telescope and the total performance of the telescope. The energy resolution wastested at four different energies by placing aluminum
moderators of different thicknesses before the LPT. In
the charge discrimination test, the secondary particles(e, p, d, t, 3He and alpha) produced by the nuclear
reactions of the 4He beam with acrylic were measured.
A schematic view of the experimental setup is shownin Fig. 1.
Figure 2 shows typical flE-E scatter plots. The
separation between different particles is very clear,which makes the assignment of particles ID easy. Twodimensional contours are applied to the scatter plot foreach particle type. An example of such contours forAcrylic(b)

AI Spinning
Wedge

Fig. 1. Schematic view of experimental setup for 4He beam
experiment at RIKEN. (a) energy resolution test. (b)charge discrimination test.

100
120
40
60
80
140
o
20
30-+---L-----L.--....I...-----'-----L...---'----+30

25

25

20
.~ . ',

15

10

5

o
o

20

40

60

80

100

120

140

Pu Ise Height E (MeV)

Fig. 2. Two-dimensional scatter plot of 0.25 mm 6.E detector versus 6 mm E-detector pulse heights.

protons is indicated as solid lines enclosing the protons in Fig. 2.
The energy resolution of each individual detector has
been confirmed using 5.48 MeV alpha particles fromthe radioisotope (241 Am). The resolution was foundto be about 12.64 and 21.23 keV (FWHM) for flE andE detectors, respectively.
As a result of the energy resolution test, the peakenergy of the pulse-height distribution of each detector
comes within 4% from the simulated pulse height, andthe full-width at half maximum is also about 4%.

National Space Development Agency of Japan

101

RIKEN Accel. Prog. Rep. 34 (2001)

Single-Charged Heavy Fragment Ion Production
in Fast He 2 + -C 60 Collision
Y. Nakai, T. Kambara, A. Itoh,*l H. Tsuchida,*2 and Y. Yamazaki
A number of studies of c 60 fragmentation have been
performed with various excitation probes. 1 - 7 ) The distribution of product ions strongly depends on the energy deposit, which is the internal energy of the precursor of fragmentation. In low-energy deposition byelectrons, atoms and collisions with the surface, c 60
emits small neutral clusters in a few micro seconds ora longer time scale after excitation. 2- 5 ) In the latter
case, the activation energy and the kinetic energy release associated with C 2 evaporation were estimated'.
The time-of-flight (TOF) peak profile for each product ion contains information on fragmentation, thatis, the kinetic energy release and lifetime. However,a part of such information is often lost due to poor
experimental resolution. We have developed a highresolution TOF mass spectrometer to obtain information on the fragmentation mechanism. Using this spectrometer , we have measured TOF peak profiles in themass range fromtoin the fragmentation byvery fast He 2+ ion impact, as reported in 1999 RIKEN
Accelerator Progress Report. We compare them withthe simulation of sequential C 2 emission based on the
Rice-Ramsperger-Kassel-Marcus (RRKM) formalism.
It is shown that the experimental results support highactivation energies and a very loose transition state, as
discussed in Ref. 8.
Each experimental TOF peak of fullerene-like fragment ions is asymmetric as shown in Fig. 1. The tails
on the longer TOF side curve much more gently thanthose on the shorter TOF side. This asymmetry becomes more obvious with heavier fragment ions. Notethat the asymmetric shapes do not arise from the massdifference in C60 with a different number of 13C because the peak widths of fragment ions are much wider
than those of C 60 ions. The thermal motion of c 60 is
not the cause the asymmetric peak, either. Roughly,
the peak intensities of(n = 1 to 5) exponentially decrease with n. This is consistent with otherstudies of fullerene-like fragment ion production.
We simulated the TOF spectrum by statistical dissociation using two sets of transition states and activation energies. In Fig. 1, we show the simulated
TOF spectra. For each set of transition state and activation energies, we determined the internal energy
distribution of parent
ions by assuming the simple exponential functional form so as to rep rod uce
the peak intensity ratios among fullerene-like fragment
ions. When the normal transition state and activationenergies, 7.1 eV for
are used, the simulated TOF

cto

cto

cto ,

*1

102

Kyoto University
Nara Women's University

a)

400

.~ 300
en

c::
~ 200
..5
100
o~. .--~. .~~~~~~~~

12800 13000 13200 13400 13600 13800 14000

TOF (ns)
500
400

b)

• Experimental- - Simulation-II.~ 300
en

c::
~ 200

. ..5

Ct8

ctO-2n

*2

500

100
o~Mm""~~~~m.~~~~~~

12800 13000 13200 13400 13600 13800 14000

TOF (ns)Fig. 1. Comparison of the experimental TOF spectra withsimulation results . Solid circles correspond to the experimental results. Solid lines correspond to the simulated results. See text for the difference between (a)and (b).

spectrum does not agree with the experimental TOF
spectrum, as shown Fig. 1 (a). However, when the veryloose transition state and high activation energy from
Ref. 8, 9.5 eV for
are used, the simulated result
agrees with the experimental spectrum fairly well, as
shown in Fig. 1 (b). Our results support high activation energies and a very loose transition state and indicate that the dominant process of fullerene-like fragment production is the sequential C 2 emission, even in
the collision of c 60 with fast He 2+ ion.

cto

References
1)
2)
3)
4)
5)
6)
7)
8)

Y. Nakai et al.: J. Phys. B 30 , 3049 (1997).
M. Foltin et al.: J. Chern. Phys. 107, 6246 (1997).
P. Weis et al.: J. Chern. Phys. 104,6246 (1996).
R . Woergoetter et al.: J. Chern. Phys. 101,8674 (1994).
M. Foltin et al.: J. Chern. Phys. 98 , 9624 (1993).
R. K. Yoo et al.: J. Chern. Phys. 96, 911 (1992).
J. Laskin et al.: Chern. Phys. Lett. 242 , 249 (1995).
J . Laskin et al.: Int. J. Mass Spectrom. 177, L9 (1998).

RIKEN Accel. Prog. Rep. 34 (2001)

Beam Plasma Experiment at RILAC Facility
A. Sakumi, T. Katayama, M. Nakamura, and Y. Oguri*
In the energy region of hundreds of ke V / u, theenergy dependence of the stopping power of oxygenions in a plasma is quite different from that in cold
matter. 1,2) Although the experimental investigation
has been conducted for a few species, it is not sufficient to explain the physics involved in beam-plasmainteraction systematically. With this background, we
have experimentally investigated the dependence of the
stopping power in the plasma on the atomic numberof the projectile with fixed incident energy, ranging
from Kr to Bi. These projectiles are available at the
CNS (Center for Nuclear Study, Univ. of Tokyo) beamline in the RILAC facility. Figure 1 shows a schematic
view of the experimental setup. A beam of 1.4 MeV /u
84 Kr 13 + ions is delivered in a single bunch. A dense
plasma is produced by irradiating a small lithium hydride (LiH) pellet with a Q-switched Nd-glass laser(,\ = 1.054j.lm, 5.5J and 30ns (FWHM)). The pellet
diameter is approximately 60 j.lm. The irradiance ofthe laser on the pellet was 2 TW / cm 2.
The energy loss of ions, which interact with the target plasma, is measured by the time-of-flight (TOF)
method. In order to filter the plasma light emission,
the TOF detector is operated in the gated mode usinga HV pulser. The laser, ion beam and the pulser aresynchronized by the digital delay generators.
To model and interpret the measured energy loss
precisely, an exact knowledge of the plasma parameters such as temperature and electron density are offundamental necessity. Plasmas with a temperature of
rvlOeV are known to produce a considerable amountof VUV and soft X-ray radiation both as line emission (bound-bound transition) and continuum (freefree transition, free-bound transition).3) The target
plasma should therefore be diagnosed by X-ray and/or
VUV spectroscopy. The electron temperature is determined from the slope of the free-bound continuum
and the electron density is estimated from the opacity of the resonance line emissions and also from Stark
broadening.
The theoretical estimate 1) of the stopping power ofthe Kr ions as a function of the incident energy is

LiH plasma target

Acceleratort ";Single ~ur¥:hsyste~

1I / ;':~madiagnostics~~~

Storageoscilloscope

Digital delay generators

Fig. 1. Schematic view of the experimental setup.

Cold

0.1

0.5

5

Beam energy [MeVlu]

Fig. 2. Stopping power in the LiH plasma estimated for
84Kr projectiles.

shown in Fig. 2. The target is a plasma with a density of 10 18 cm- 3 and a temperature of rv15eV. We
estimate a large enhancement of the stopping power inthe plasma compared with that in the cold matter.
References
1) T. Katayama: J. Plasma Fusion Res. 70, 323 (1994).
2) A. Sakumi et al.: Nucl. Instrum. Methods Phys. Res. A(2001), to be published.
3) P. Nicolosi, E. Jannitti, and G. Tondello: Appl. Phys.
B 26, 117 (1981).

Research Laboratory for Nuclear Reactor, Tokyo Instituteof Technology

103

RI KEN Accel. Prog. Rep. 34 (2001)

Vacancy Formation Energy of Indium Determined by Using the
Positron Annihilation Age-Momentum Correlation TechniqueN. Suzuki, Y. Nagai,* Y. Itoh, A. Goto, and T. Hyodo
The positron annihilation technique has been used tomeasure the vacancy formation energy E v for various
metals.
If the material contains only one type of vacancy,
Ev is determined through the quantitative analysis of
the change in the positron annihilation parameters byassuming the two-state trapping mode1. 1 ,2) According
to this model, the S-parameter, which is defined as
the number of central region of the Doppler-broadened
511 keY annihilation ')'-ray energy spectrum divided by
the total counts, satisfies,
S - Sf( Ev )
Sv - S ex: exp - kBT '(1)

where Sf and S v are the specific S-values corresponding to the positrons in the bulk and in the vacancy,
respectively, which are usually assumed to increase linearly with temperature.
Although Ev for indium has been measured by many
workers, those values are not mutually consistent but
are scattered over 0.39- 0.59 (eV).3) This discrepancy
is probably caused by the uncertainty of Sv. Since thepositron trapping in indium does not saturate evennear the melting temperature, the uncertainty of S v
disturbs the result of the analysis.
In the present study we developed a new method
to overcome this difficulty using the positron agemomentum correlation (AMOC) technique. In thepresent method, the AMOC spectrum N(p , t) is characterized in t erms of the time-dependent line-shape parameter S(t) , which is defined as
S(t) = J±6.p N(p , t)dp
N(p , t)dp ,J(2)

where ~p is an arbitrarily determined momentum
width. Since the lifetime of the trapped positrons isappreciably longer than that in the bulk, S v can be
determined by extrapolation using,S v = lim S(t).
t--+ oo(3)

Thus it is expected that Ev can be determined fromthe data. for the temperatures, where saturation trapping of the positrons does not occur, by fitting the Sparameter using the value of S v obtained by AMOC.
Figure 1 shows the time-dependent S-parameter S (t )for indium at 413 K. It is seen that S(t) increases gradually with time. It represents the increase in the fraction of the trapped positrons. S (t) almost saturates
after about 0.5 ns. This indicates that almost all the
Institute for Materia l Research, Tohoku University

104

0.5~r---~----~------'-----~~

l

~0.5

0.5 "*"---~""~fTI;,,,*,~~-if.='Y++I

00

0.5

'I

O.~~--~----~------~----~~

otime (ns) 1

Fig. 1. Time evolution of S(t) for In at 413 K.

0.5. : time-integrated S

b 0.5/::":8y

t)

lO.5

In

00

0.5

melting point•

0.51L...----L.---3....L.OO-----'---4-0L-O-..LJ

Temperature(K)Fig. 2. S-parameter for In plotted against the temperature.

positrons in the bulk have annihilated or are trappedin vacancies in this time range. The almost constantvalue of S(t) in this time range (solid line in Fig. 1)
corresponds to Sv.
The closed circles in Fig. 2 show the S-parameter obtained by the conventional Doppler broadening measurements and the triangles show the Sv values thus
obtained. The solid line and the dashed line represent Eq. (1) and a linear function simultaneously fitted
to the data for Sand Sv, respectively. The Ev thus
determined is 0.48 ± 0.02 (eV).
References
1) B. Bergersen and M. J. Stott: Solid State Commun. 7,1203 (1969).
2) D. C . Connors and R. N. West: Phys. Lett. A 30, 24(1969).

3) P. Rice-Evans, T. Hlaing, and I. Chaglar: Phys. Lett.
A 60, 368 (1977), and references therein.

RI KEN Accel. Prog. Rep. 34 (2001)

High-Resolution Soft X-Ray Measurements in 2.3 keY lu
15N7+ Ions Transmitted through a Capillary
Y. Iwai,*l 8. Thuriez ,*2 R. Hutton,*3 Y. Kanai, H. Oyama, K. Ando,
H. Masuda,*4 K. Nishio,*4 K. Komaki, *l and Y. Yamazaki
When a slow highly charged ion approaches a solid
surface, the ion resonantly captures target valence
electrons into excited states. X-rays emitted from
2.3 keY lu 15N7+ ions transmitted through a thin
Ni micro capillary foil were measured with a highresolution soft X-ray spectrometer. The micro capillarytarget was f'.J 1 mm 2 in area with a thickness of f'.J 1 J.Lm
and had a multitude of straight holes f'.J200 nm in diameter. The spectrometer consists of a concave grating and a back-illuminated CCD. For details of thespectrometer, see Ref. 1. Our measurements' energy
resolution in FWHM was 3.1eV at 500eV, the energy
accuracy was 0.5 eV at 500 eV, and the time window,
which depends on the width of the slit and the energy of the ion beam, was 37 ps for 2.3 keY lu ions. For
this experiment, we used a beam of 2.3 keY lu 15N7+
ions from a 14.5 GHz Caprice-type electron cyclotron
resonance (ECR) ion source at RIKEN.
X-ray spectra were taken at three points downstream of the microcapillary target along the ion beam.
The points were immediately downstream of the target (T = 0) , 0.35 mm downstream (T = 0.52 ns), and2.75 mm downstream (T = 4.10 ns). Figure 1 shows
the spectrum at the target immediately downstream.

Table 1. Electronic core configurations.
Experiment625.1 ± 0.7eY
593.0 ± 0.7 eY
500.3 ± 0.5 eY
430.5 ± O.4 eY
425.8 ± O.4eY

Ref. data
625.3 ey2)592.9 ey2)
500.3 ey2)
500.2ey2)430.7ey 3 )426.3ey 3)

Configuration
4p ....... ls
3p ....... ls
2p ....... ls
2p ....... ls
ls2p ....... ls2
ls2p ....... lS2

Term
2P3/2 ....... 28 1 / 2
2P 3/ 2 ....... 28 1 / 2
2P 3 / 2 ....... 28 1 / 2
2P 1 / 2 ....... 2S 1 / 2
IP 1 ....... ISO
3P 1 ....... ISO1000~- 2p-ls

100

P,

~
'8

. ·A ·,'h2p Ipi _ls2 ISO-ls2p 3PI _ 1s2 ISO

1 ..

=
,Q
...

~

10

~

1-

=

.... iCI>/oS' .J..--i... . ..........

......... -1
0.1

0

2

3

4

Time (ns)Fig. 2. X-ray decays of the 2p 2P 3/ 2,1/2, 1s2p Ip 1, and
3P I . The error bars, except for the 3p first and Ip lastpoints, are mainly due to the beam stability.

160
140
120
~

·S

=

,Q

100

...

80

~

60

~

=
.s
~

40
20
.A.

0
350

400

./

450

500

550

11

-

600

650

Energy (eV)Fig. 1. Spectrum of K X-rays measured with the spectrometer immediately downstream of the target (T = 0),
for 2.3 keY lu 15N7+ ions transmitted through a Ni microcapillary. The spectrum has four peaks, at 625.1 ±0.7eV, 593.0±0.7eV, 500.3±0.5eV, and 430.5±0.4eV.
*1 Institute of Physics, Graduate School of Arts and Sciences,
University of Tokyo*2 Quantaflow, France*3 Department of Physics, University of Lund, Sweden*4 Department of Applied Chemistry, School of Engineering,Tokyo Metropolitan University

In all, five peaks were observed, at 625.1 ± 0.7 eV,
593.0 ± 0.7 eV, 500.3 ± 0.5 eV, 430.5 ± 0.4 eV, and425.8 ± 0.4 eV. According to theoretical calculation
and reference data, the five peaks are attributed tocore electronic transitions of H-like 2) 4p 2P3/2 - t Is
28 1/ 2 (625.3 eV), 3p 2P 3/ 2 - t Is 28 1/ 2 (592.9 eV), 2p
2P 3/ 2,1/2 - t Is 28 1/ 2 (500.3eV, 500.2eV), He-like 3)
Is2p 1P 1 - t 1s2 180 (430.7eV), and 1s2p 3P 1 - t 1s2 18 0(426.3eV). The observed transitions with their coreconfigurations are summarized in Table 1.
Figure 2 shows the X-ray intensities for the 2p
2P 3/ 2,1/2, 1s2p 1P 1, and 3P 1 as a function of the timeafter the ion leaves the micro capillary target. This result provides information on the decay process related
to outer shells.
References
1) Y. Iwai et al.: RIKEN Rev. 31, 34 (2000).
2) R. L. Kelly: J. Phys. Chern. Ref. Data 16, Suppl. 1(1987).
3) W. R. Johnson, D. R. Plante, and J. Sapirstein: Adv.
At. Mol. Opt. Phys. 35, 255 (1995).

105

RIKEN Accel. Prog. Rep. 34 (2001)

Charge State Distribution of Highly Charged Ions Passing throughMicrocapillaries
D. Dumitriu,*l Y. Kanai, Y. Iwai,*2 Y. Morishita, and Y. Yamazaki
The properties of hollow atoms related with theirformation mechanism have been intensively studied
by many groups. 1 ,2) In typical ion-surface experiments
the study of the intrinsic nature of hollow atoms in
the first generation- hollow atom above the surface(HAA)- is rather difficult, because the time interval
between the HAA formation and its arrival at the surface is shorter than its intrinsic lifetime. Beam Capillary Spectroscopy (BCS) is a new and powerful method
recently developed 3 ,4) which allows direct observationof HAA in vacuum by using a thin micro capillary asa target. We have measured the charge state distribution f(qf) of the ions transmitted through a Ni microcapillary target as a function of the final charge
state qf. 22 ke V oq+ and Nq+ ions (q = 5, 6, 7) fromRIKEN 14.5 GHz ECR ion source were used as incident
projectiles. The charge states of the ions transmitted
through the target were separated and analyzed by a
new charge state analyzer built in Atomic Physics Lab.
It consists of two sets of deflectors combined with aceratron. The deflectors are arranged in a "cascade"type configuration, the beam being deflected on vertical direction in his passing from one deflector towards
another, until it reaches the ceratron. The first deflector consists of planar electrodes inclined at 15° (withrespect to the beam direction) and the second one isa 128° cylindrical sector type. One of the electrodes
for each deflector is grounded. As high voltages up
to 20 kV can be applied on both deflectors, the analyzer can in principle separate rather high charge states(13 + from 14+) for incident energies in the range of <25 ke V / q. The ceratron is located very close to the exitof the second deflector. A movable Faraday cup locatedbetween deflectors is used for adjusting the beam. The
Ni microcapillary target (area: 4 mm 2 , length: 3.8 J-Lm)
is set in front of the analyzer. Results are shown in
Fig. 1 and they present the following features: (a) One
electron capture (qf = q - 1) dominates in the chargechanged fractions , independent of the projectile andinitial charge state. (b) Almost neutralized projectiles(q = 1) are produced in large quantities and comparable to that for one electron capture. (c) The othercharge states fractions (1 < qf < q - 1) are lower thanthose for qf = 1 and qf = q - 1. (d) For the same initial charge state q, almost similar behavior was foundin the final charge state distributions.
The total fraction CF of the all transmitted ions
*1

*2

106

Horia Hulubei National Institute for Physics and Nuclear
Engineering, Romania
Institute of Physics, Graduate School of Arts and Sciences,
University of Tokyo

100

~

(8)

10

i

0

•

0

~
0

• •
0

0.1
100

[]

(b)

10
0
0

0

0

0

• • • •
0.1
100

g

(c)

10

•

•

0

~

1

•

0

3

4

0

1

o. 0

•

2

5

6

7

8

Final Charge State

Fig. 1. Charge state distributions f(qf) of 22keV oq+(filled symbols) and Nq+ (open symbols) ions transmitted through the Ni microcapillary target. (a) q = 7, (b)q = 6, and (c) q = 5.

who captured electrons from microcapillary walls canbe estimated by CF = 2d c/ p with de = (2q)1 / 2/W ,where de is the critical distance for one electron capture, p is the nominal radius of the microcapillary and
W is the binding energies of the target valence electrons. The CF formula is available under assumptions
that the beam is entering parallel with the capillary
axis and with the capillaries being of perfect cylindrical shape. The present target has capillaries with radii
varying between 50 nm on the backside and 90 nm on
the front side. Considering a nominal radius of 50 nm
has been chosen the expected CF is rv4.1 % for q = 7
and decrease to 3.5% for q = 5. The total fraction CF
measured is larger, probably due to different conditionsof the beam and the capillary from the ideal conditions
as mentioned above. The present results are in qualitatively agreement with the theoretical one. 5 ) Also thepresent measurements for N6+ ion beam can be qualitatively compared with a previous measurement with
N6+ (28 keY) incident projectile on aNi microcapillarytarget 6 ) with a different nominal radius (250 nm) andlength (1.5 j.Lm). We found an overall agreement for
final charge states distribution pattern in both cases.
In conclusion, the transmitted charge state distribution related to hollow ion formation has been studied
for two projectiles 0 and N, with the same total energy 22 ke V and charge states from 5+ to 7+. The
transmitted charge state fractions depend both on theinitial projectile charge state as well as on the nature of

the projectile. We are planning to measure K X-rays
emitted by the transmitted ions in coincidence withthe final charge states as a next step.
References
1)
2)
3)
4)
5)

J. P. Briand et al.: Phys. Rev. Lett . 65, 159 (1990).
A. Arnau et al.: Surf. Sci. Rep. 27, 113 (1997).
Y. Yamazaki et al.: J. Phys. Soc. Jpn. 65, 1199 (1996).
Y. Yamazaki: Int. J. Mass Spectrom. 192, 437 (1999).

K. T6kesi et al.: Nucl. lnstrum. Methods Phys. Res. B
164/165, 504 (2000).
6) S. Ninomiya et al.: Phys. Rev. Lett. 78, 4557 (1997).

107

RIKEN Accel. Prog. Rep. 34 (2001)

Angular Distribution Measurements of Electron Capture Processes
for X4+(X~C, N, O)-He Collisions at
Energy Region below 40 eV lu
M. Hoshino,* 1\1. Kitajima,* Y. Nakai, Y. Kanai, H. Tanaka,* and Y. Yamazaki
The study of multi-electron capture processes inhighly charged ion (HCI)-atom collisions has been thesubject of a number of experimental and theoreticalinvestigations. Angular differential cross-section measurements of very slow collisions are of great interest
because the angular differential cross-sections become
more sensitive to the shapes of the interaction potential curves as the collision energy decreases. However, since difficulties arise in producing very slow andwell-collimated HCI beam below 100eVlu, experimental studies of very slow collisions between HCI andatoms have been limited. Recently, we have developed a crossed-beam experimental apparatus for angleresolved energy gain spectroscopy of very slow collisions. We utilize the ion beam from the 14.5 GHz
CAPRICE electron cyclotron resonance (ECR) ion
source at RIKEN. I ) Here, we present angular distribution measurements of electron capture processes forX 4 + (X=C , N, O)-He collision below 40eV/u.
Figure 1 (a) shows the typical energy gain spectrum of C 4 + - He collision at 23 eV I u and 4 deg. An
intense peak due to the double-electron capture process C4 + (ls2) + He ~ C2 + (1s22s2) + He 2+ is seen in
Fig. 1 (a). The single-electron capture peak was too
weak to be resolved from the background in the present
measurement. Both single- and double-electron capture processes are seen in the energy gain spectra ofa N4 + -He collision at 32 eV I u shown in Fig. 1 (b).
The most intense single-electron capture peak corresponds to the capture into the N 3 + (2p2) state, whichis the transfer excitation process. Intense peaks dueto the capture into the N 2+ (2s2p2) state is seen forthe double-electron capture in the N 4 + -He collision.
We have also measured the energy gain spectra of an
0 4 + -He collision at 20 eV I u. The dominant singleelectron capture is the capture into the 0 3+ (2p 3)
states, which is the transfer excitation process. The
dominant double-electron capture peaks are observed
for the capture into the 0 2+ (2s2p 3) state.
Figure 2 represents the angular distribution of C 2 +ions produced in the C 4 +(ls2) + He ~ C 2+(ls22s2) +He 2+ at collision energy of 39 and 23 eV lu. We havecalculated differential cross sections for C 4 + (1 S2) +He ---+ C2 + (1S22s2) + He 2+ with the close-coupling
method using the potential curves of Boyd et al. 2) at 39
and 23 eV lu. The calculated results, convoluted withexperimental angular resolutions of 1.0 and 1.8 deg. for
39 and 23eV lu, respectively, are also shown in Fig. 2.
Department of Physics, Sophia University

108

(a)
Product C2+
252p 252

Primary Beam C4 +

nl

11 ~
260 280
Energy (eV)!

o 10 20 30 40
Energy Gain (eV)(b)

Primary Beam N4 + Product N3+

Product N2 +1251~S n2~52P 1 11 ~r22i22p

E.~J\, ~

430 450 0 10 20 30 0 10 20 30 40
Energy (eV)Energy Gain (eV)Fig. 1. (a) Energy gain spectrum of C 4 + -He collision at
23 eV / u and 4 deg. (b) Energy gain spectrum of N 4 +_He collision at 32 e V / u and 0 deg.

2'

'c::J

.ci

~
~

'iii

c

2
E
Cl

c

.........

.~

:t::

~

en

o

2
4
10
Scattering Angle SLab (deg.)

Fig. 2. Angular distribution of C 2+ ions produced in theC 4 + (ls2) + He ---+ C 2+ (ls228 2) + He 2+ at collision energies of 39 and 23 e V / u (.). Calculated differential crosssections convoluted with the experimental angular resolution are shown together (- ).

Clear differences in the peak positions between experimental and calculated results are seen for both energies. The peak positions of the calculated results are
shifted to larger angles compared to the present experimental results. Much more accurate potential curves
are required.
References
1) M. Kitajirna, Y. Nakai, Y. Kanai, Y. Yamazaki, and Y.
Itoh: Phys. Scr. T 80, 377 (1999).
2) R. Boyd et al.: J. Chern. Phys. 106, 6548 (1997).

RIKEN Accel. Prog. Rep. 34 (2001)

X-Ray Spectroscopy of Highly Charged Ions Using Superconducting
Tunnel Junction Detector
T. Ikeda, Y. Iwai ,* Y. Kanai, H. Kato, K . Kawai , H. Miyasaka, Y. Morishita, Y. Nakai , T. Oku, C. Otani,
H. Oyama, H. Sato, H. M. Shimizu, Y. Takizawa, H. Watanabe, and Y. Yamazaki
A superconducting tunnel junction (ST J) detector
is a newly developed X-ray detector which has meritsof single-photon detection and high energy-resolution.
For the X-ray energy region, crystal spectrometers andsemiconductor-based detectors are widely available. A
crystal spectrometer has high energy-resolution but
low acceptance. On the other hand, a semiconductorbased detector has a large · acceptance and provides
timing information, but the energy-resolution is not
as good. Measurements using the ST J detectors provide not only high energy-resolution, but also timing
information and high counting-rates. The principle ofthe photon detection in the ST J is based on the excitation of quasiparticles due to the breaking of Cooper
pairs in a superconductor. The dissociation energy of
one Cooper pair is on the order of me V. However, a
semiconductor-based detector needs an excitation energy of ",3 eV for one electron-hole pair. Therefore,
the small dissociation energy of the ST J allows more
precise energy-dispersive spectroscopy. Moreover, theSTJ has a sensitivity for ,-ray, UV, visible, IR andneutral- and charged-particles.
The ST J fabricated at RIKEN has a layer structure of Nb (150 nm thick, lower electrode)/ Al (50 nm)/AIO x / Al (50 nm)/Nb (150 nm, upper electrode) : Itssensitive region has an area of 100 x 100 J.lm 2 . The
ST J characteristics and the fabrication process havebeen described elsewhere. 1) During measurement, theST J is cooled to less than 0.4 K and voltage-biased
with a magnetic field of 50- 300 Gauss to suppress the
dc-Josephson current. The output signals are amplified by either a superconducting quantum interference
device (SQUID) amplifier or a charge-sensitive amplifier. Our STJ was characterized with 5.9keV X-rays
from an RI source, and energy resolution of 41 eV wasachieved.
The ST J was used in an experiment involving collision between highly charged ions (HCI) and a solid
target with a Caprice-type ECR ion source at RIKEN.
Ions extracted from the ion source were collimated bya four-jaw slit to a size of 6 x 6 mm 2 , and then led to atarget chamber. The ions were Ne 9 +, 0 7 + and Ar 14 +accelerated by 10 kV. The intensity was between 50
and 100 nA. The target was a stainless steel with aflat surface at room temperature, the angle between
the target surface and the beam being 45°. X-rays
emitted in a direction perpendicular to the beam were

,

N:+

350

;

.... ,..........!..............

(840-890eV)··_·. . tupper f · ···. . ·. +················i···· pulsar....... ..J ~...~~~r~.~l·· · · · · · · · i· · · · · · · .i .....
1300.5 250re.:i 200

1

=
=
o

. ~ . ~"...':"................ :................' . ········.. ···11.. ····.. ···.. ···..1'·····,

1...... . ........ Iower_.. . _.. . j ... .. .... .....

150

U

electrodie

100
50

o0

100

200

300

700

ChannelFig. 1. Energy spectrum of the K Q X-rays from Ne 9 + ions.

detected by the ST J. The distance between the beam
center and the ST J surface was 24 mm. Since the ST J
must be cooled to about 0.38 K , it was shielded by two
100-nm-thick Al films from thermal radiation by thetarget. In this measurement , a charge-sensitive amplifier was employed. The beam intensity was controlled
so that the counting rate was between 100 and 500
counts per second. Figure 1 shows a raw spectrumof the K a X-rays from Ne 9 + ions. In the plot, there
are two peaks of X-rays corresponding to the photon
absorption in the upper and lower electrodes and apulsar peak for the evaluation of electronic noise. The
observed peak broadening due to the electronic noiseof the readout system corresponds to 20- 30 eV. The
photon absorption in different electrodes can be easily
identified by a SQUID amplifier. 2 ) Under our collisionconditions, the Ka peak consists of the satellite X-rays
from ions related to different numbers of L-shell holes.
For Ne ions , the energy of the satellite X-rays ranged
from 840 to 890 eV. The Ne Ka peak shown in Fig. 1
has an asymmetric shape with a tail on the higherenergy side. This can be attributed to the satellite
X-rays. The shape is consistent with a high-resolution
measurement by Andra et al. 3 )References
1) H . 8ato et al.: Jpn. J. Appl. Phys. 39, 5090 (2000).
2) T. Ikeda et al.: IEEE Trans. Appl. 8upercond., in press.
3) H. J. Andra et al.: Z. Phys. D 21 , 8135 (1991).

Institute of Physics, Graduate School of Arts and Sciences,
University of Tokyo

109

RIKEN Accel. Prog. Rep . 34 (2001)

Measurement of Charge State Distributions and Scattering Angular
Distributions of 5 ke V / q Nq+ Ions Transmitted throughMicrocapillaries for Multiple Electron Transfer Study
D. Murakoshi,*l N. Okabayashi,*l Y. Iwai,*l Y. Morishita, H. A. Torii,*lY. Kanai, K. Nishio,*2 H. Masuda,*2 K. Komaki,*l and Y. Yamazaki
We have been studying interactions between ionsand metallic surfaces, using a microcapillary foil asa target. As a slow highly charged ion approaches ametallic surface, target electrons are transferred to theions when the ions are still far above the surface. Electrons are transferred into highly excited states while
the inner shells of the projectile are kept open. Such an
atom (ion) with many electrons in highly excited transient states and many inner shell vacancies is calleda "Hollow Atom" above the surface. Various experiments so far have proven that the Classical Over Barrier model (COBm) reproduces various aspects of theobservations. However, even if hollow atoms are generated above the surface, they hit the target surface immediately after their formation as long as the surfaceof the target is flat. Ninomiya et al. l ) suggested that a
micro capillary target enables the extraction of hollow
atoms generated above the surface into vacuum, andshowed that we can obtain important information on
multiple electron capture processes of highly charged
ions .
Recently, we measured the final charge state distributions for 800eV /q Xe q + (3 ::; q ::; 9) ions transmitted through Ni microcapillaries,2) which were well reproduced with the Monte Carlo simulations taking into
account Auger cascading processes of hollow atoms(ions).3)
We also measured scattering angular distributionsfor 800eV /q Xe 6 + incident ions, which are shown in
Fig. 1. As is seen in the figure, the angular divergence gets larger as the final charge state increases,
which is qualitatively different from a naive expectation. The COBm indicates that the critical distancede where electron transfer occurs between an ion anda metallic surface is given by rv ~/W, where q is
the incident charge state and W is the work functionof the target metal. In other words, the charge stategets lower as the distance of the ion to the surface getssmaller, which is supported by the same Monte Carlo*1

Institute of Physics, University of Tokyo*2 Tokyo Metropolitan University

110

Fig. 1. Contour plots of scattering angular distributions forXe 6 + transmitted through Ni microcapillaries, where
scattering angles are represented in degree.

simulation referred to above.
To understand this puzzling tendency of the scattering angle, we are now preparing a new experiment on
5 keY /q Nq+ at RIKEN 14.5 GHz Caprice, employing
the new capillary target with significantly straighter
pores.
References
1) S. Ninomiya, Y. Yamazaki, F. Koike, H. Masuda, T.
Azuma, K. Komaki, K. Kuroki, and M. Sekiguchi:
Phys. Rev. Lett. 78 , 4557 (1997).
2) D. Murakoshi, N. Okabayashi, Y. Iwai, Y. Morishita,
H. A. Torii, K. Komaki, and Y. Yamazaki: Prog. Rep.
Atom. CoIl. Res. Jpn., to be published.
3) K. Tokesi, L. Wirtz, C. Lemell, and J. Burgdorfer: Phys.
Rev. A 61 , 020901R (2000).

RIKEN Accel. Prog. Rep. 34 (2001)

Behavior of Ions in Superfluid Helium
R. Saneto,*1 Y. Fukuyama, Y. Matsuo, and Q. Hui*2
We are currently developing a method to trap ion
beams in superfluid helium (He II) and to study spectroscopic properties of atoms with short-lived radioactive nuclei, which are produced at accelerator facilities.
He II is expected to be a suitable medium for trappingions because it can instantly stop the ion beams withhigh kinetic energy. 1) Then, various methods of spectroscopy can be applied for trapped ions and atoms
in He II because it is transparent in the wide wavelength region from radio frequency to vacuum ultra
violet. Microwave detection combined with the opticalpumping method will enable measurement of hyperfine
splitting 2,3) of alkali and alkali-earth atoms and ions.
The experiments of laser spectroscopy in He II havebeen carried out on many kinds of impurity, mainly
neutral atoms. However, only a few kinds of ion such as
Ba+ and Yb+ have been observed thus far. 4 ,5) It is also
necessary to study the physical properties of ions in He
II, such as their optical transitions and mobilities, inorder to develop a method for observing the unstable
nuclei in He II. Recently, we measured the ion current
in He II to study the behavior of ions.
The experimental setup is illustrated in Fig. 1. A
metal Dewar with quartz windows is filled with He II.
The pressure of the He gas in the Dewar is about 6
Torr , which corresponds to that of liquid He at a temperature of about 1.6 K. A quartz cell is placed above
the liquid surface and the cell itself is also filled withHe II by transferring liquid He utilizing the fountaineffect of He II. The liquid surface in the cell is maintained at a full level. A metal sample is held about
1 cm above the quartz cell. An ablation laser beam
(532 nm, approximately 20 mJ / pulse) is focused onto
the sample through one of the windows. Neutral atoms
and atomic ions are produced by laser ablation. Only
positively charged ions are injected into He II by theelectric field generated at three electrodes that are set
in the quartz cell in such a way that the upper electrodestays just 2 mm below the liquid surface. A high voltage is applied to the upper electrode (grid) and a low
voltage is applied to the middle one (Frisch grid). The
lower collector is connected to the digital oscilloscopethrough the current amplifier. The distance between
the grid and the Frisch grid is 4 mm, whereas that of
the Frisch grid and the collector is 1 mm. The ion current detected at the collector is amplified by a factorof 10 9 and monitored with the digital oscilloscope.
Figure 2 shows the observed ion currents of Sr+ in
He II at various electric fields between the grid and the
Frisch grid. Laser ablation is performed at time zero
*1

*2

Keio University
University of Electro-Communications

YAG lasercollectorrHelloscilloscope

amplifierFig. 1. Experimental setup.

4
Egrid - frisch grid

3

1
~

-

600V/ cm-- 480V/ cm..... 360V/ cm..... 240V/ cm---480V/cm

2

+'

c:::

~::J
C.)

.....................

c:::
.Q

o
-1

o

10

20

30

40

drift t ime ems)

Fig. 2. Observed ion currents.

which is indicated by the current flowing into the Frischgrid. By increasing the applied voltage, the peak position of the ion current appears faster and the widthof drift time becomes narrower; the peak intensity of
the current becomes stronger, as well. It is estimatedfrom this result that about 108 Sr+ ions, which is muchlarger than the number required for optical detection(104 ) , are introduced into He II. We are now attempting to detect the laser-induced fluorescence (LIF) spectrum of Ba + and Sr+. We are also preparing a new
cryostat for on-line spectroscopic measurement of unstable nuclei in He II.
References
1)
2)
3)
4)
5)

N. Takahashi et al.: Physica B 284/288, 89 (2000).
T. Kinoshita et al. : Phys. Rev. B 49 , 3648 (1994).
T. Yabuzaki et al.: Z. Phys. B 98 , 367 (1995).
H. J. Reyher et al.: Phys. Lett . 115, 238 (1986).
Y. Moriwaki: Eur. Phys. J. D, 13, 11 (2001).

111

RIKEN Accel. Prog. Rep. 34 (2001)

Development of New Technique to Measure Isotope Shift andHyperfine Shift Using Atomic Beam Deflector
Y. Fukuyama, Y. Matsuo, and I. Tanihata
Now we can create the wide variety of RI atoms fromthe stable region to near the dripline. There are many
atoms whose isotope shift and hyperfine shift have notbeen measured systematically. So far, most of the isotope shift and hyperfine shift measurements were carried out using mainly collinear laser spectroscopy. For
the RI atoms far from stability, this method is not sensitive enough because the laser induced fluorescence
whose detection efficiency is not so high is used as detection method. It is required to develop highly efficient way for laser spectroscopic study of RI atoms.
In recent years, techniques of laser cooling and trapping neutral atoms have been developed rapidly. They
provide us a possibility to manipulate the motion of
atoms with laser radiation pressure force. Inspired bythese techniques we are developing the atomic beam
deflector,!) which deflect the RI atoms by radiationpressure force only when the frequency of laser beam
is nearly resonant to the electric transition of the RI
atoms. Deflected atoms reach the forward detector(det.2, see Fig. 1), subsequently beta rays are detected.
Since the quantum efficiency of scintillator to detect abeta ray is much higher than that of photomultipliertube to detect a photon, this system will provide muchhigher sensitivity to measure the isotope shift and hyperfine shift of RI atoms far from stability.
Figure 1 shows schematic diagram of atomic beam
deflector. The atomic beam deflector consists of two
pairs of cylindrical mirrors. A concave mirror with
R = 1050 mm and a convex mirror with R = 1000 mm
are placed along the concentric circle. Both mirrors
have lengths of 200 mm. The laser beam first hit
the edge of the convex mirror and travel between two
mirrors as shown in Fig. 1. When the incident angle of laser beam is sufficiently small, wavefronts oflaser beam are approximately parallel to the surface

Laser

scintillator--- ------------~et.1

D.

deflected
atomic beam det.2

Fig. 1. Illustration of atomic beam deflector.

112

of cylindrical mirrors. The RI atoms are introduced
into atomic beam deflector parallel to the wavefront oflaser beam and the frequency of laser is tuned slightly
red from the resonance. Atoms absorb the laser lightfrom both side. Atoms travel along the curved trajectory parallel to the wavefront. For the atoms, which
escape from the curved trajectory, the absorption rateof the laser light which has the direction to push backatoms to the trajectory is higher than that of the laser
light of the opposite direction because of Doppler effect. Atoms move approximately along the wavefrontof laser beam after the atomic velocity becomes parallelto the wavefront. The laser frequency should be swept
sufficiently slow compared to the beta decay time of
RI atoms. It is possible to apply this technique to RI
atoms which have the beta decay time less than few
seconds.
The minimum radius R of curvature for the atom
to follow the wavefront determined from the ratio of
momentum transfer rate between atoms and photonsh/2)..is and the longitudinal momentum mv of theatom to be R = 2mv 2 i s )"/h, where m and v are themass and velocity of atom, is the spontaneous lifetimeof the upper state and)" the wavelength of the transition. Our primary goal is to measure the isotope shift
and hyperfine shift for lithium and magnesium. For
lithium atom which has 0.1 eV kinetic energy and incident angular divergence of 0.1 rad, the efficiency of deflection is calculated to be almost 100% and deflected
angle is about 0.2 rad. When the distance from the endof deflector to the detector is not less than 150 mm,
deflected atomic beam and non-deflected atomic beam
will be separated completely. With this method using
one to three laser frequencies it is possible to measure 30 kinds of atoms. These atoms are mainly alkaline, alkaline earth, and metastable rare gas atoms
which have strong S-P electric transition with closed
cycle. To combine this deflector with laser-laser orlaser-microwave double resonance, it is possible to obtain the accuracy of the isotope shift and hyperfine
shift in frequency dimension determined by the widthof laser or microwave spectrum.
In recent years Wada et al. are developing the RF
ion-guide system 2 ) to provide low kinetic energy RI
atomic beams. We suppose this deflector to be usedwith the RF ion-guide system. This deflector is expected to be a powerful tool to measure the isotope
shift and hyperfine shift of RI atoms which has low
kinetic energy and low flux density. Because the efficiency of particle detection is usually much higher thanthat of optical detection, in ideal case the efficiency ofparticle detection is unity. We are currently preparing
a CW-laser system for the atomic beam deflector.

2) T. Wada et al.: RIKEN Accel. Prog. Rep. 33, 180(2000) .

References
1) F. Shimizu et al.: Chern. Phys. 145 , 327 (1990).

113

RIKEN Accel. Prog. Rep. 34 (2001)

Development of a High-Intensity Slow-Positron Source
for Cooling Highly Charged Ions II
N. Oshima, T. M. Kojima, D. Dumitriu, A. Mohri, H. Oyama,
T. Kambara, Y. Kanai, Y. Nakai, M. Wada, and Y. Yamazaki
A technique for cooling highly charged ions (HCIs)
using positron plasmas is under study, where a large
number of positrons must be stored in an electromagnetic trap. I ) In order to capture positrons at a high accumulation rate, a high-intensity slow positron-source
is under construction. 2)
Slow positrons are produced by moderation of fast
positrons emitted from a (3+ decay radioisotope. Theenergy spread of slow positrons so prepared is typicallya few eV. In our study, a combination of a 22Na radioactive source (1.5 GBq) and a solid neon (Ne) moderator is used. 2)
Figure 1 shows a schematic diagram of the positronsource assembly.
An encapsulated 22Na positronsource is mounted on a cold finger of a refrigerator andis cooled to 5 K so that a rare-gas solid moderator isformed on t he front surface of the source. The assembly is electrically floated to accelerate slow positrons
to an energy of 0- 200 eV.
A schematic drawing of the positron beamline isshown in F ig. 2. The solenoid and coils installed along
the beamline yield an axial magnetic field of about
10 mT and guide the slow positrons. The positron
beam profile is observed using a multichannel plate(MCP). A scintillation counter is prepared close to the
MCP to evaluate the positron beam intensity by measuring the count rate of positron annihilation gamma
rays. Since the downstream of the beamline after thesolenoid guides not only positrons but also HeIs, a lensand a profile monitor for HCrs are also installed.

refrigerator(5K)~~~~~~~HI insulator~

thermometer
positron source

slowe+
extraction grid
ground grid
thermal shieldFig.!. Schematic diagram of the slow-positron source
assembly.

114

switchingmagnetsourcescintillat i on
counterm:::;;tt=-

c=::IJ

ion beam lension beam monitor

1

coi I

coo ling t rap

Fig. 2. The slow-positron beam line.

Fig. 3. Positron beam profile observed using the MCP .
The MCP active diameter (a ring diameter) is 10 mm.

The profile of the extracted positron beam observed
using the MCP is shown in Fig. 3. The beam diameter was approximately 5 mm. The beam intensity was
1.5 x 106 / sec and the efficiency of the moderator wasdetermined to be 1.0 x 10- 3 , which is defined by the rat io of the number of the extracted slow positrons to t henumber of (3+ decays of the radioisotope. This moderation efficiency is still 20% of that reported in Ref. 3.
Further development of the slow positron-source is underway.
References
1) N. Oshima et al. : Proc. Int. Workshop on Advanced
Techniques of Positron Beam Generation and Control,
Wako (RIKEN, 1998), p. 64.
2) N. Oshima et al.: RIKEN Accel. Prog. Rep. 33 , 255(2000).
3) R. G . Greaves et al.: Can. J. Phys. 74, 445 (1996).

RIKEN Accel. Prog. Rep. 34 (2001)

Stable, High-Efficiency Positron Moderator with Tungsten Mesh
Y. Nagashima,*l T. Kurihara,*2 F. Saito, Y. Itoh, A. Goto, and T. Hyodo*l
The development of high-efficiency stable moderators has been an essential factor in the developmentof slow positron beams. The efficiency E of a moderator is defined as the ratio of the number of extracted
slow positrons per unit time to the source activity. The
highest efficiency has been accomplished by using inert
gas solids as the moderation material. 1 ,2) The value of
E for solid neon moderator is reported to be as high as
7 x 10- 3 . However , it is not easy to keep such a highefficiency stably for a long time because this moderator
requires a cryogenic system.
Tungsten has been widely used for the moderationmaterial because of its stability and relatively highmoderation efficiency. 3) The value of E for the transmission moderator of tungsten single crystal foil is reported to be 5.9 x 10- 4 and that of tungsten polycrystal foil is 2.6 x 10- 4.4) Although the backscatteringmoderator of tungsten single crystal exhibits E of oneorder of magnitude higher than that of the transmission moderator 5 ) and is useful for a re-moderator, its
efficiency when used as a primary moderator would
be low because a significant fraction of the moderated
positrons are shielded by the source on the path of thebeam.
Several authors have tested stacks of tungsten
meshes as moderators. 6 - 10 ) Since meshes have large
surface areas, high efficiency is expected. Furthermore,
the cost is considerably lower than that of thin foils.
In this paper, we report the development of a stable, high-efficiency moderator with tungsten mesh.ll)
The moderator consists of a six-overlapping tungsten
mesh. The size of each mesh is 7 mm x 24 mm. They
are 85% transmission with 20 J1m wires. The meshes
were annealed in vacuum by passing an electric current
through the tungsten foils wrapping the meshes. The
temperature was raised and maintained at 2000°C for
2 minutes. After annealing, the meshes were quickly
transported in air and installed in the moderator assembly of the beam apparatus.
The moderator is placed 1 mm away from the window of the positron source. It is held with insulating bushings at a potential of +350 V with respect to the chamber and 9 V below the source. The
positrons reemitted from the moderator are accelerated to 350 eV by a 95% transmission tungsten gridplaced 3 mm downstream from the moderator.
The experimental system used to measure theefficiency of the moderator is magnetically guided*1*2

positron beam apparatus with a trochoidal Ex B filter.
The magnetic transport system provides an approximately uniform axial field of 0.015 T. After leaving
the E x B filter, the beam enters an insulating tube,
where the positrons can be accelerated by floating up
the whole of the source side. The base pressure of thesystem is 1.0 x 10- 6 Pa.
In order to measure the beam intensity, the beam
is incident on a carbon sample of 15 mm in diameter.
The number of the positrons which annihilate on thesample are counted by detecting the 511-keV ,),-rays
using a high purity Ge detector. The efficiency of thedetection system is calculated by placing a calibrated
22Na source at the sample position.
The beam intensity is determined to be 6.7x 104e+ /swhen the source activity is 4.5 mCi (166 MBq). Thisvalue is almost independent of the beam energy forE e+ > 350 eV. If we assume that the positron transmission efficiency of the beam apparatus is 100%, themoderation efficiency E is 4.5 X 10- 4.
The moderator is stable. The efficiency measured
after a few months was found to be the same as theabove value.
The moderation efficiency E is higher than that for
any other tungsten mesh moderator reported so far.
It is comparable with the single crystal tungsten foilmoderator. The mesh moderator has the advantagethat the treatment is far easier and the cost is far
lower than the single crystal. Further improvementof the efficiency is expected by optimizing the numberof overlapping meshes.
References
1) A . P. Mills, Jr. and E. M . Gulikson: Appl. Phys. Lett.
49, 1121 (1986).
2) R. G. Greaves and C. M. Surko: Can. J. Phys. 74,445(1996).
3) J. M. Dale et al.: Surf. Interface Anal. 2, 199 (1980).
4) E. Gramsch et al.: Appl. Phys. Lett. 51, 1862 (1987).
5) A. Vehanen et al.: Appl. Phys. A 32, 163 (1983).
6) L. S. Fornari et al.: Phys. Rev. Lett. 51 , 2276 (1983).
7) N. Zafar et al.: Hyperfine Interact. 89, 243 (1994).
8) N. B. Chilton and P. G. Coleman: Meas. Sci. Technol.
6, 53 (1995).
9) J. P. Merrison et al.: Appl. Surf. Sci. 149, 11 (1999).
10) R. Zhang et al.: Rad. Chern. Phys. 58, 639 (2000).
11) Y. Nagashima et al.: Jpn. J. Appl. Phys. 39, 5356
(2000) .

Institute of Physics, Graduate School of Arts and Sciences,
University of Tokyo
Institute of Materials Structure Science (IMSS) , High Energy Accelerator Research Organization (KEK)115

RIKEN Accel. Prog. Rep. 34 (2001)

Development of an EBIS Using High-T c Superconductors
A. Endo,* H. A. Torii,* K. Yoshiki Franzen,* K. Komaki,* and Y. YamazakiElectron beam ion source (EBIS) is widely used as
an effective source of highly charged ions. The ions aretrapped in the magnetically confined electron beam
and are successively ionized by the electron impact.
The current density of the electron beam is one of
the important parameters; it determines the maximum
charge of produced ions. In oder to realize a highdensity beam, conventionally a superconducting magnet is used. However, the magnet greatly increases
the size of the apparatus and the running costs, withhigh liquid He consumption. Alternatively, a few EBIS(EBIT) without superconducting magnets have beendeveloped. 1 - 3 ) The designers preferred downsizing at
the cost of a strong magnetic field. Instead of this cost ,we are attempting to develop an EBIS using a high-T csuperconducting material. It decreases the size of the
EBIS and enables operation at liquid N2 temperature
with a sufficientry strong magnetic field.
The high-T c superconducting material we used is
YBa2Cu07-x, which has a high critical current density (Jc); its application as a bulk magnet has been
investigated. 4 ) There are different methods to magnetize bulk. Field cooling (FC) using a static magnetic
field is an effective method that is widely used. However, it requires an additional strong magnet , which
increases the size of the apparatus. Recently, a new
method called pulsed field magnetization (PFM) has
been developed, in which the magnetizing coil can be
kept comparatively small. 5 ,6) We adopted this type of
EBIS, where the magnetizing coil (1.4 mm x 3.0 mm
wire, 182 turns) is set in a liquid N2 reservoir. We
used three ring-shaped bulk magnets of 51 mm outer
diameter, 15 mm inner diameter and 12 mm thickness
each. Figure 1 shows the results of our magnetizing
test. By repeatedly applying pulses of 11 ms width ata peak magnetic field of a few tesla, we succeeded inmagnetizing bulks up to 1 T at liquid N 2 temperature.
A schematic view of the EBIS is shown in Fig. 2.
Three bulk magnets are sealed in a stainless steel container which is in contact with the liquid N2 reservoir
wall. Electrons produced by a Pierce-type electron gun
with a 3-mm-¢ spherical cathode are injected into themagnetic field. The shape and the potential of the electrodes are determined by computer simulations. According to the simulations, a 100 mA electron beam iscompressed to a diameter of 100 /-Lm, corresponding toa current density of 1000 A/cm 2 at the center of thedrift tube. Both electron gun and electron collector
are floated at a negative voltage (up to -30 kV). Electrons are accelerated between the gun and the drift
tubes. After passing through the ionizing region, elecInstitute of Physics, University of Tokyo

116

1.2

:. .- •
I
I

I
I

I

l-

0.8

E
NO.6

I
I
I
I
,------.,•

3.6 em

•

CO

0.4

•

0.2
0

• •
-8

-6

•

•
-4

•
-2

0

2

4

6

8

z [cm]
Fig. 1. Distribution of trapped magnetic flux at 77 K.

Magnetizing CoilBu~~j~~~ul~In~'J Drift

Electro:iJ I

I~Extractor~~

Electron Collector
Liquid N2 Reservoir_Iron

Fig. 2. Schematic view of our EBIS.

trons decelerated to 1 ke V and are collected by thewater-cooled electron collector. Produced ions are accelerated by the same potential, and extracted.
This EBIS is now under construction.
References
1) K. Okuno: Jpn. J. Appl. Phys. 28, 1124 (1989).
2) K. Kusakabe et al.: Phys. Scr. T 73, 378 (1997).
3) K. Motohashi, A. Moriya, H. Yamada, and S.
Tsurubuchi: Rev. Sci. Instrum. 71, 890 (2000).
4) M. Morita, M. Sawamura, S. Takebayashi, K. Kimura,
H. Teshima, M. Tanaka, K. Miyamoto, and M.
Hashimoto: Physica C 235/240, 209 (1994).
5) U. Mizutani, T. Oka, Y. Itoh, Y. Tanagi, M. Yoshikawa,and H. Ikuta: Appl. Supercond. 6, 235 (1998).
6) T. Oka, Y. Itoh, Y. Yanagi, M. Yoshikawa, H. Ikuta,
and U. Mizutani: Physica C 335 , 101 (2000).

RIKEN Accel. Prog. Rep. 34 (2001)

A Possibility of a New Stripe Ordered State of Spins and Holesin the Overdoped La2-xSrxCUl-yZny04 Studied by JLSR
I. Watanabe, M. Aoyama,* M. Akoshima,* T. Adachi,* Y. Koike,* and K. Nagamine
Anomalous behavior of the transport phenomena
with suppression of the superconductivity in Znsubstituted La2-xSrxCUl-yZny04 around x = 0.21
has been reported Refs. 1- 3 suggesting a possibility ofthe existence of a new stripe ordered state of spins andholes in the overdoped region. We have carried out themuon spin relaxation (p'sR) measurements in order toinvestigate the Cu-spin state in these single-crystals of
La2_xSrxCUl_yZny04.4)
j.lSR measurements were carried out at the RIKENRAL Muon Facility (RIKEN-RAL) at the RutherfordAppleton Laboratory in the UK. The two-exponentialfunction of Ale->'lt + Aoe- Aot was used for the analysis. Ao and AI, Ao and Al are regarded as the initialasymmetries and the depolarization rates, respectively.
Figure 1 shows the zero-field j.lSR time spectra of
the Zn-substituted single-crystal obtained at various
temperatures down to 0.3 K. The time spectrum deviates from the Gaussian-type at low temperatures below
3.5 K, indicating the appearance of a fast depolarizing
component. At low temperatures below 2 K, the asymmetry of the muon spin polarization decreases quickly
by nearly two thirds within a time range of 0.5 j.lsec after the arrival of muons in the sample. No clear coherent precession of the muon spin 5 ) has been observed.
Fgiure 2 displays the results of the analysis. The initial asymmetry of the muon spin decreases suddenly
around 2 K with decreasing temperature for the Znsubstituted crystal, which correlates with the increaseof AI' The Ao is enhanced with decreasing temperature and exhibits divergence at 2 K. These are typicalS

1.5

Laz_xSrxCul_yZny04
x=0.21, y=O.Ol

(1)

~ 1.0
~

00

eo.3 Kb, 2.0 K

D3.0K
~3.5
K
5.0K
40K

<t:
'"0
(1)

.....N

ca
§

0.5

0

Z

0

0

5

10

Time (J.Lsec)
Fig. 1. Zero-field j..tSR time spectra of the Zn-substituted
single-crystal of La2-xSrxCUl-yZny04 with x = 0.21
and y = 0.01 at various temperatures. Solid lines are
the best fit results.

____

1.5

~

x=O.21, y=O.Ol
1.0 t&D 000

~

"I

§
3

..f

"1

"I

-

0

0.5 t-

?08

""I

"'I

x=O.21,y:::O
rco 00 0ot- 0~J..LWIL~J.WL....J'-L.J.J..LL"IIL-LJ
I

030 rT"l-rmm--rr,.,..,..".-.-n"TTTlTT""-noL.-'-I..J.llWJ-J.:Z,;.u=--L....LJ.J.J..Wi...-L.J

0.3

9---- 0.2 'gon::t---;;; 0.1 -..-c::

o

0.1

" "I

"I

o
0
"I

""'I

""'I

-

0
0

I-

'6,900 ",I10

100 0.1

c:P,

o

0

00

1

10

!)

100

Temperature (K)Fig. 2. Temperature dependences of the initial asymmetryof the slow depolarizing component (AD) and the depolarization rates of the fast (AI) and slow (AD) depolarizing components in the Zn-substituted (y = 0.01) and
Zn-free (y = 0) single-crystals of La2-x SrxCul-yZny04
with x = 0.21.

characteristics in the case that a static magneticallyordered state of Cu spins appears in the La-214 systems as observed in the previous j.lSR studies. 5 )It has been reported that the resistivity of thepresent Zn-substituted single-crystal with x = 0.21
exhibits upturn below about 80 K in every directionof the crystal axes. 3 ) In addition, no Meissner effecthas been confirmed at temperatures above 2 K. These
results suggest that doped holes tend to be localized
at lower temperatures. Since a static magneticallyordered state of Cu spins are revealed by j.lSR to appear at low temperatures below 2 K in the same singlecrystal, it is suggested that the ground state of this Znsubstituted single-crystal is a sort of coexisting state ofstatically ordered Cu-spins and localized holes. Therefore, it is plausible that a new stripe ordered state ofspins and holes exists in the overdoped region as suggested from the transport measurements. 3 )References
1)
2)
3)
4)
5)

N. Kakinuma et al.: Phys. Rev. B 59 , 1491 (1999).
Y. Koike et al.: J. Low Temp. Phys. 117, 1157 (1999).
T. Kawamata et al.: Phys. Rev. B 62 , R11981 (2000).
I. Watanabe et al.: Phys. Rev. B 62 , R11985 (2000).
I. Watanabe et al.: Hyperfine Interact. 86, 603 (1994) .

Graduate School of Engineering, Tohoku University

117

RIKEN Aeee!. Prog. Rep. 34 (2001)

Level Crossing Resonance Study of a Two Dimensional Dimer
System SrCu2(B03)2
A. Fukaya, 1. Watanabe, and K. Nagamine
In low dimensional quantum spin systems, e.g.
Haldane-gap and spin-ladder systems, the ground stateis a non-magnetic singlet state due to quantum effects.
In such compounds, muon spin relaxation is not expected, at least, at low temperatures, since a numberof thermally excited triplet is quite small. However, invarious compounds with the singlet ground state, ananomalous enhancement of the muon spin relaxation(p'sR) , which means existence of electronic magnetic
moment and a spin freezing , is observed at low temperatures. Although an intrinsic property of system ora probe effect of muon has been discussed, the origin
has not been clarified yet. At present , we speculatethat the origin is that implanted muons locally distort
the lattice and the singlet state is locally destroyed.
To confirm our speculation, we have applied a levelcrossing resonance (LCR) method to a two dimensional
dimer system SrCu2(B03h, in which anomalous spin
freezing is observed in p,SR. If implanted muons locallydistort the lattice , it should be reflected in resonancepositions and/or line shapes of resonance. Thus, we
can study an effect which implanted muons bring tolocal environment by comparing the result of NQR. 1)
We have performed LCR measurement at Port 2 of
the RIKEN- RAL Muon Facility. A powder sample of
SrCu2(B03h was used.
In Fig. 1, we show the longitudinal field (LF) dependence of average asymmetry with time region from
5 p,s to 10 p,s , Aave, at 50 K and 3.1 K. We found the decrease of Aave around 90 G, which suggests resonance ofmuon and some nucleus. The amplitude of resonancedecreases at 3.1 K. The resonance position does notdepend on temperature. In addition to the decrease of
Aave around 90 G, we also found the decrease of Aavearound 700 G (inset of Fig. 1). This decrease of Aaveis quite small and quite broad.
We can estimate resonance fields from the result of
Cu-NQR. 1 ) If implanted muons produce neither additional electric field gradient nor distortion of the lattice, the resonance position can be estimated from thefunction,2)(1)

where I'N and I'J.L is a gyromagnetic ratio of a nu-

118

0.245
0.240

I IIISI IIII I

c 0.2350§ 0.230

T

T

;;.,

~
~ 0.225

e

++

11)

>

~

"~ 0.23

0.2 15<: 0.22

0.165

C

o

*++++

0.220

Ol)

0

1000
LF G)

2000

1000

2000

(b) T=3 .1 K

0.160

E

E 0.155
;;.,

~
11)

b/)

0.150

e
11)

..<

0.145
0.140

LF(G)

O. 135 oL---'-------'--"'-----'----1
1OO-::----'------'--'----'---;2:;;;:OO:;--"'-----L-.J

LF(G)Fig. 1. LCR spectra at (a) 50 K and (b) 3.1 K. The insets
show LCR spectra up to 2.5 kG.

cleus and one of muon. H~ c and H~c are, respectively, a local field at the nuclear site and one at themuon stopping site. HLF is a longitudinal field. Since
NQR frequency for 63Cu and 65CU under zero-field is23.0 MHz and 21.0 MHz ,1) the resonance positions ofmuon- 63 Cu and muon- 65 Cu are expected to be, respectively, ",1900 G and ",1700 G. In SrCu2(B03h, besides 63CU and 65Cu, three elements of 38Sr, 11 Band
12B have a nuclear quadrupole moment. At present, elements which contributes the observed resonance havenot been determined yet. To obtain information in
more detail, we are planning theoretical calculation
and additional LCR experiments.
References
1) H. Kageyama et al.: Phys. Rev. Lett. 82 , 3168 (1999).
2) G. M . Luke et al.: Hyperfine Interact . 31, 29 (1986).

RIKEN Accel. Prog. Rep. 34 (2001)

JLSR Study on Magnetic Properties of p-NPNN.Cu(hfac)2
S. Ohira, 1. Watanabe, F. L. Pratt,* and K. Nagamine
0.20

p-NPNN (p-nitrophenyl nitronylnitroxide) is thefirst organic bulk ferromagnet, and is also known to
be a ligand for transition and rare-earth metal ions.
One such metal ion complex, p-NPNN·Cu(hfach (hfac= hexafluoroacetylacetonate), has a crystal structure
which consists of alternating chains of p-NPNN andCu(hfach. The chains are connected by 7r-7r and headto-tail overlap of the p-NPNN molecules, resulting ina two-dimensional (2D) network. 1) The ac susceptibility (Xac) shows a cusp at 1.22 K suggesting that
2D antiferromagnetic interchain interaction operates
in the 2D network, and the susceptibility also showsa sudden increase at rvO.60 K, suggesting a spin canting. The detailed magnetic properties of this material have not however been investigated by any othermethods . We therefore performed a p,SR study on pNPNN·Cu(hfach in order to study the magnetic structure and spin dynamics of the system microscopicallyand to understand the magnetic properties of p-NPNN
by investigating its properties as a ligand.
The experiment was carried out at the RIKEN-RAL
Muon Facility in the UK. Polycrystalline samples were
mounted on a silver plate with Apiezon-N, and fixed
onto the sample holder of a 3He cryostat. ZF- andLF-p,SR measurements were carried out from 0.3 K to
80 K using this cryostat.
ZF-p,SR time spectra is shown in Fig. 1. Slow relaxation of the muon spin due to nuclear dipole fields
was observed above rv2 K, indicating that the system
was in a paramagnetic phase. The muon spin relaxation gradually became faster below 2 K, and the shapeof the time evolution of the muon spin dramaticallychanged between 1.2 K and 1.1 K. The initial asymmetry suddenly decreased, and recovery of the muon
spin polarization was observed in the time region of
t 2:: 6 p,s, indicating the appearance of static internal
fields.
The ZF time spectra were well fitted by the following
equation:A(t) = Apower e-(Apowert) ~ + A fast e- Afastt + B.

(1)

The first term describes the muon spin relaxation
caused by nuclear and/or electronic spins and the second term the fast spin depolarization of muons which
experience large hyperfine fields through forming muonium (= p,+e-) or a muonium radical state. The
third term, B, is constant and includes background(Abg) and the finite muon spin polarization held constant at ~ of the initial value by the component ofstatic internal field which is parallel. to the initial
muon spin direction . Figure 2 shows the temperaAlso University of Oxford. : 80K
0: 2. 0K

0 .15"' : 1.3K
6.

>.

b

E
E

1.2K

e : 1.lK

Q)

0. 10

0 : 0.3K

~
...:

0 .05

Time I p.s

Fig. 1. ZF-J.LSR time spectra of p-NPNN·Cu(hfac)2.

I

I

I

I-

/f
A,o~,

OJ
~

0 .05
0 .04
0.03

a 0 cp 0<90.05 I-..............

0.00

.1
1.0

0

0

?

..~ f"

1-

Alan.j .••••

0 .02

A bg

0.01
0 .00

0 .5

1.0

1.5

... ... ... ... ...

B~ IIJJi. ...
I
0 .5

0

0

Q)

S
S
>,

I

-

~o

b 0.10II

0. 15 -

I.1
5.0 10.0

T /,I
I
50 .0100 .0

K

Fig. 2. Temperature dependence of initial asymmetry. The
constant value of B above 1.2 K corresponds to background (Abg). The increase of B below 1 K is assigned
to the ~-tail of a ZF Kubo-Toyabe component.

ture dependence of the initial asymmetries, Apower andB (= A bg + A tail ) . Both Apower and B are almost
temperature-independent above 1.2 K, while Apowersuddenly decreases and B increases below 1.1 K. This
result suggests that a long-range magnetically orderedstate occurs below rv 1.2 K.
Our result is quite different from the susceptibility
one. Taking into account the Xac result, the internal magnetic field between 0.6 K and 1.22 K should be
fluctuating due to a short-range ordering. In our p,SR
study, however, the internal magnetic field at the muonsite was static in this temperature region, suggesting along-range ordered state below 1.2 K with no evidenceof any further change at 0.6 K.
References
1) T. Origuchi et al.: Mol. Cryst. Liq. Cryst. 296, 281(1997) .

119

RIKEN Accel. Prog. Rep. 34 (2001)

JLSR Study on a 2D Weak-Ferromagnetic Organic Radical Crystal
S. Ohira, K. Mukai,* K. Ohiro,* and 1. Watanabe
Pure organic radical magnetic crystal, which isnamely composed only of light elements such as C, H,
Nand 0 , are of much interest in recent years. An
organic radical crystal 1,3,5- triphenyl-6-oxoverdazyl(TOV) is known to be a weak-ferromagnet. The
magnetic susceptibility measurement on this material showed a broad maximum in the dc susceptibility at 6 K, indicating that the system is the S = 1/2
one-dimensional (lD) Heisenberg system, and suggested the appearance of a weak-ferromagnetism byincrease of the susceptibility below rv5 K.l) On theother hand, the result of heat capacity is describedby an S = 1/2 2D Heisenberg antiferromagnet withJ /kB = -4.5 ± 0.2 K, and the long-range magnetic ordering was not observed there. 2 ) We carried out ZFand LF-p'sR experiments on TOV, in order to study
the details of the magnetically ordered state microscopically.
The experiment was carried out at the RIKEN-RAL
Muon Facility in the UK, using a 3He cryostat down to
0.3 K. Polycrystalline samples of TOY were prepared.
They were mixed with Apiezon-N to fix on a silver
sample holder.
Figure 1 shows ZF-p'sR time spectra of TOV. Above
rv5 K, a random static internal field due to nuclear
dipolar fields was observed. The changes of internal
field and spin dynamics caused by the low-dimensional
short-range magnetic ordering were not observed. Below rv5 K, clear muon spin precession was observed, indicating the onset of a unique internal magnetic fieldat the muon site. A magnetic phase transition is expected at rv5 K. The fact that a muon spin precession
signal is observed evidences the appearance of a longrange magnetic ordering in the system. This result is
consistent with that of the previous susceptibility measurement, and the transition temperature is similar tothat obtained from the susceptibility measurement.
The precession frequency of the muon spin can beconverted to the magnitude of the internal magnetic
field at the muon site by using an equation w = TJ.LH,
where w /27f is the precession frequency of the muon
spin, H the internal field at the muon site, and T J.L a
gyromagnetic ratio of muon, respectively. The temperature dependence of the internal field at the muon site
below 5 K shows appearance of spontaneous magnetization in the system, as shown in Fig. 2.
From our fl,SR study, it was confirmed that a longrange magnetic ordering appeared below rv5 Kin TOV.
This result supports the previous magnetic susceptibility measurement. Enhancement of the muon spin
relaxation associated with a short-range magnetic orEhime University

120

0 .3

>-

....
.....,
Q)

5.6K

S
S
>.

0 .2

(/J

-<t:

4.9K

~

co

4K

~

3K
0 .1

0 .3K

0

2

4

3

Time / J-LS

Fig. 1. ZF-/LSR time spectra of TOY. Asymmetry includes
constant background. The vertical scale refers to 0.3 K
data, and the others are shifted by 0.04 for each vertically.

1250• • • •••

100'----'"0

Q)

75

cS-..

...•

web

'+-<

(;j

••

50

Q)

-+-'

C

25

•

•

TOV

0

0

2

3

4

5

6

Temperature / K
Fig. 2. Temperature dependence of the internal magnetic
field at the muon site.

dering was not observed in our study.
References
1) R. K. Kremer et al.: Chern. Phys. Lett. 230, 255 (1994).
2) M. Mito et al.: J. Phys. Soc. Jpn. 66, 2147 (1997).

RIKEN Accel. Prog. Rep. 34 (2001)

First Observation of a Full Dispersion Curve in a Spin-Ladder
K. Katsumata, M. Matsuda, R. S. Eccleston,*l S. Brehmer, *2 and H. J. Mikeska*2
Quantum antiferromagnetism in lower dimensions
has attracted much attention from condensed matterphysicists. In recent years, spin ladder systems havebeen the subject of intense theoretical and experimental studies. I ) A spin ladder is composed of n coupled
one-dimensional magnets with an interchain (or rung)interaction J J.. (Jrung ). The most extensively studied
spin ladder system is the one in which the magnetic
atoms have spin quantum number S = ~ with an antiferromagnetic intrachain (or leg) interaction J II (Jleg)
as well as an antiferromagnetic J J.. . The magnetic
properties of such S = ~ antiferromagnetic ladders(AFLs) change radically depending on whether n iseven or odd. 2) The ground state of an S = ~ AFL witheven n is a singlet with an energy gap to the lowest excited triplet. On the other hand, an S = ~ AFL with
odd n has no gap in the excitation spectrum. Despite
a progress in theoretical studies, little is known experimentally about the low energy excitation spectrum ofa spin ladder. Here, we report the first observation ofa full dispersion curve for the low energy excitation ina spin ladder material using a pulsed neutron source.
The compound chosen for this study is
La6Ca8Cu2404I. The parent compound Sr14Cu2404I
consists of both CU02 chains and CU203 ladders ofcopper ions. A number of experiments showed thatthe two-leg ladder has a spin gap (the bottom of theexcitation spectrum) of 28- 56meV.3) An important
point in the Sr14Cu2404I system is that stoichiometric
Sr14Cu2404I contains hole carriers. These holes in
the ladder may broaden the excitation spectrum andmake the observation difficult. On the contrary, thecompound La6Ca8Cu2404I has no holes in the ladder,therefore, we expect that a cleaner spectrum will beobserved.
The single crystals of La6Ca8Cu2404I were grownusing a traveling solvent floating zone method. An array of four mutually aligned single crystals was used.
The neutron scattering experiments were carried out
on the High Energy Transfer Chopper Spectrometeron the ISIS Pulsed Neutron Source at the RutherfordAppleton Laboratory, UK. The experiments were carried out with incident neutron energies of 150, 300, 500
and 600 me V that were monochromated by a rotating
Fermi chopper that was phased to the source.
The dispersion data as obtained from the observed
magnetic peak positions are shown in Fig. 1 together
with the theoretical fits described below. The signals
at 30- 60 me V originate from the bottom of the ex*1

*2

ISIS Facility, Rutherford Appleton Laboratory, UK
Institut fur Theoretische Physik, Universitat Hannover,Germany-... 200

>Q)

I

\

\

\

E

,:"150

.!!
o

t:

...>-

f! 100

...

C)

Q)

t:
W

50

.300 maV
0500 maV... 600 maV- - Jring=O- Jring=0.15Jrung

T=20 K

OI.......L.....J.......J.--.l...-.L.-.L..--'---'L.........L....-L......J.--L--.L.-.L..--'---Ao0.4

0.8 1.2
Q (A- 1 )1 .6

Fig. 1. The dispersion curve for the low energy excitationin the spin ladder material La6Ca8 CU24 0 41. The solidand broken curves are theoretical ones discussed in thetext.

citation band in the first Brillouin zone and those at
70- 200 meV from the excitations in the second and thethird zones. As is evident from the figure, when we reduce all the experimental points to a single Brillouinzone, these points constitute a full dispersion curve forthe lowest energy excitation. As far as the authors areaware, this is the first experiment 4) that observed thefull dispersion curve in a spin ladder material.
We have studied theoretically the low energy excitation in an S = ~ two-leg spin ladder. The standard
analysis of experimental data for spin ladders uses thetwo parameters Jleg and J rung only, assuming the simplest symmetric structure of the two legged ladder. For
this model we have calculated the dispersion of the lowest triplet excitation using the Lanczos method for ladders with 12 rungs (i. e. 24 spins) and periodic boundary conditions. With Jrung and Jleg as only exchange
parameters we obtained the best fit to our data for
J rung = 53 me V and Jl eg = 106 me V, corresponding to
Jleg/ J rung = 2, as shown in Fig. 1. They are, however,not consistent with both (i) the expectation from ageometrical consideration that the Cu-O-Cu exchange
on legs and rungs should be approximately equal (dueto identical exchange paths and approximately equal
distances and also in analogy to 2D materials such as
La2Cu04) and (ii) the results of an exact diagonalization calculation for the electronic state of cuprates performed by Mizuno et al. ,5) which gives J rung rv150 meV

121

and Jleg rv 170 me V, corresponding to Jleg / J rung = 1.1.
We, therefore, considered whether or not the introduction of additional exchange interactions gives a fit
to our data with comparable accuracy and concomitantly is consistent with the expectation Jrung ~ J 1eg .
We calculated the dispersion with an additional ringexchange J ring with the following Hamiltonian,'H ring = 2Jrin g[(8 1 .82 )(8 3 . 8 4 )+ (8 1 .84 )( 8 2 .83 ) - (8 1 .83 )(8 2 .84 )]. (1)The solid curve in Fig. 1 shows the theoretical one
with J run g = 110 meV, Jle g = 110 meV, and J ring =16.5meV. 4 )122

References
1) For a review, see E. Dagotto and T. M. Rice: Science
271 , 618 (1996).
2) E. Dagotto, J. Riera, and D. Scalapino: Phys. Rev . B
45 , 5744 (1992).
3) See for example, K. Kumagai, S. Tsuji, M. Kato, andY. Koike: Phys. Rev. Lett. 78 , 1992 (1997).
4) M. Matsuda, K. Katsumata, R. S. Eccleston, S.
Brehmer, and H.-J. Mikeska: Phys. Rev. B 62 , 8903
(2000).
5) Y. Mizuno, T. Tohyama, and S. Maekawa: Phys. Rev.
B 58, R14713 (1998) .

RIKEN Accel. Prog. Rep . 34 (2001)

First Results of Laser Spectroscopy of Antiprotonic Heliumat the New Antiproton Facility AD of CERN
M. Hori,*l J. Eades,*l E. Widmann,*2 H. Yamaguchi,*2 J. Sakaguchi,*2 T. Ishikawa,*2 R. S. Hayano,*2
H. A. Torii,*3 B. Juhasz,*4 D. Horvath,*5 and T. Yamazaki
With the birth of a new antiproton beam facility (the Antiproton Decelerator) at CERN a new experimental program on high precision studies of Antiprotonic Helium was started in 2000 as a part of
the Asacusa Collaboration. Antiprotonic Helium isa metastable system of pHe+ atoms and retains long
lifetimes of 3- 4 J.1,S even in dense helium targets. 1 ,2) Asmuch as 3% of the antiprotons stopped in helium are
captured into metastable states with large principal(n38) and angular momentum quantum numbers(l n - 1). Its laser resonance spectroscopy was initiated in 1994,3,4) and series of experiments were carriedout 5- 9 ) at LEAR.
The AD provided a pulsed beam containing 2 x 10 7
antiprotons, with an energy of 5.3 MeV, a pulse-lengthof 250 ns, and a repetition rate of 1 pulse per 2 minutes.
We made new experimentations including Cerenkov
counters for analog detection of delayed annihilation
spectra and pulsed laser systems. Metastable pHe +atoms were produced by injecting a single antiproton
pulse into a cryogenic helium gas target.
The charged pions produced in the annihilation weredetected using two Cerenkov counters. The Cerenkov
light was measured with a gatable fine-mesh photomultiplier (Hamamatsu Photonics R5505GX-ASSYII)
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0
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Fig. 2. The density shifts of 6 transitions of metastableantiprotonic helium atoms (left). The resonance profilesof the corresponding transitions (right).
3000

4000

5000

6000

7000

8000

9000

10000

time (n5)Fig. 1. A typical delayed annihilation time spectrum takenby the analog method.
*1
*2

*3
*4

*5

CERN, Switzerland
Department of Physics, University of Tokyo
Institute of Physics, University of Tokyo
Institute of Nuclear Research of the Hungarian Academy of
Sciences, Hungary
KFKI Research Institute for Particle and Nuclear Physics,
Hungarydeveloped especially for this experiment. At the arrival
time of the antiprotons, the electron multiplication in
the photomultiplier was deactivated by adjusting thevoltage potential of the dynodes, thereby suppressing
the overwhelming burst of photoelectrons caused by
the prompt annihilation. Afterwards the detector was
reactivated, producing a continuous pulse lasting morethan 15 J.1,S. This waveform, which reflects the delayedannihilation time spectrum, was recorded using a digital oscilloscope with an analog bandwidth of 1 GHz.

123

The metastable atoms were irradiated by a single laser pulse fired into the target, which induced
transitions from metastable states to Auger-dominatedshort-lived states. This forced the annihilation of otherwise long-lived antiprotons and thereby producing a
sharp spike in the delayed annihilation time spectrum.
A dye laser (Lambda-Physik Scanmate 2E) pumpedby the second harmonic (A = 532 nm) of a Q-switched
Nd:YAG laser (Coherent Infinity) was used, to produce laser pulses with a width of 4-6 ns, a diameter of
1 cm, a bandwidth of 0.4-0.6 GHz, and a power density of about 0.1- 1.0mJ/cm2 per pulse. A typical analog pulse shape is shown in Fig. 1. This was taken
as a one-shot pulse, including more than 105 delayedannihilation events. With two successive laser pulsed
tuned at 726 nm two resonent annihilation spikes wereobserved.
In the first period we searched for unknown transitions successfully. The frequency shifts of six transitions due to collisions with other helium atoms were
measured (Fig. 2), and the zero-density frequencies deduced. Thus, their transition frequencies were determined to a precision down to 1.3 x 10- 7 . The results
agree with recent three-body QED theories,1O,l1} evenfor transitions involving unstable states of 10-ps lifetime. The best agreement of ;S 2 x 10- 7 was obtained

124

for two ultraviolet transitions having the smallest frequency shifts of < 1022 GHz/cm 3 . When combinedwith the known antiprotonic charge-to-mass ratio, theresults indicate that the mass (or charge) is in agreement with that of the proton to a precision of 7 x 10- 8 ,nearly an order of magnitude better than previous values.
References
1)
2)
3)
4)

M. Iwasaki et al.: Phys. Rev. Lett. 67, 1246 (1991).
T. Yamazaki et al.: Nature 361 , 238 (1993).
N. Morita et al.: Phys. Rev. Lett. 72, 1180 (1994).
R. S. Hayano et al. : Phys. Rev. Lett. 73, 1485 (1994);
Phys. Rev. Lett. 73 , 3181 (1994); F. Maas et al.: Phys.
Rev. A 52, 4266 (1995).
5) T. Yamazaki et al.: Phys. Rev. A 55 , R3295 (1997).
6) E. Widmann et al.: Phys. Lett. B 404, 15 (1997).
7) H. A. Torii et al.: Phys. Rev. A 59, 1 (1999).
8) M. Hori et al.: Phys. Rev. A 57, 1698 (1998).
9) T. Yamazaki et al.: Chern. Phys. Lett. 265 , 137 (1997);
B. Ketzer et al.: Phys. Rev. Lett. 78 , 1671 (1997); J.
Chern. Phys. 109, 1662 (1998).
10) V. I. Korobov and D. Bakalov: Phys. Rev. Lett. 79,
3379 (1997); V. I. Korobov: Hyperfine Interact. 119,185 (1999).
11) Y. Kino, M. Kamimura, and H. Kudo: Hyperfine Interact. 119, 201 (1999).

3. Radiochemistry and Nuclear Chemistry

RIKEN Accel. Prog. Rep. 34 (2001)

In-Beam Mossbauer Study on Valence States of 57Fe Decaying from
57Mn Implanted into KMn04 (I)Y. Kobayashi, K. M. Kubo,*l Y. Yamada,*2 A. Yoshida, H. Ogawa,*3 and F. Ambe
Mossbauer spectroscopy combined with an ion implantation technique provides unique information on
the final lattice position, dynamical behavior andchemical states of implanted probes in a solid. A
lot of emission Mossbauer studies have been performed to investigate 57Fe produced by EC decay of
57 Co, as a typical implanted ion, into various matrices. However, there have been only two applicationsof 57Mn,1,2) which is also another mother source of
57Fe, in Mossbauer experiments because 57Mn is a
short-lived nuclide, T 1 / 2 = 1.45 min. About 80% of
57Mn decays directly to the Mossbauer level of 14.4 keY
through the j3- -decay process. It is known that aftereffects caused by the j3-decay around the decaying
probes are not very serious compared to those by theEC decay.
Mn sits next to Fe in the periodic table. However,the chemical properties of Mn are much different fromthose of Fe and Co. Mn occurs in various oxidation
states, from 2+ up to 7+, in ordinary solidstate chemistry. Different oxidation states are expected to be synthesized for 57Fe arising from 57Mn decay, comparedwith that from 57 Co. Therefore, Fe species in exotic
oxidation states and in an unusual oxygen configuration might be observed after the decay from 57Mn inan appreciate matrix.
In this study, the in-beam Mossbauer technique wasapplied to obtain information concerning the oxidation
state of 57Fe arising from 57Mn in KMn04, in which
Mn ions are in a 7+ state.
In-beam Mossbauer spectra of 57Fe arising from
57Mn in KMn04 are shown in Fig. 1. Each spectrum
was accumulated over 20 hrs. The center shift is given
relative to iron metal at room temperature, and thesign of velocity is in the emission Mossbauer experiment. The spectrum obtained at 25 K could be analyzed preliminarily by two singlets, which are indicatedby (a) and (b) in Fig. 1. The center shifts of components (a) and (b) were obtained to be 0.80mm/s and-0.25 mmls, respectively. The area intensity of component (b) was almost equal to that of component (a)at 25K.
The results at 25 K were used as a reference tothe correlation between oxidation states of Fe andthe center shifts of chemical compounds coordinatedwith octahedral or tetrahedral configurations of oxygen atoms. 3 ) This correlation is almost ideally linear
*1

*2

*3

106

104
102
(/)

~

::J
0
0
"C
II)

100

104

.t:!

iii

E

0
z 102

100
98

-4

-2

o

2

4

Velocity (mm/s)

Fig. 1. In-beam Mossbauer spectra of 57Fe arising from
57Mn implanted into KMn04 at 25 and 155 K.

up to an oxidation state of 4+. However, for the higher
oxidation states, the deviation from the linearity becomes obvious because of the increase in the covalencyof Fe-O bonding. A preliminary result from this correlation suggests that components (a) and (b) correspond to an ionic Fe 2 + and a covalent Fe5+, respectively.
The spectrum at 155 K, on the other hand, was not
obtained with sufficient statistics, but it could be fitted
by the two components in the same manner as that at
25 K. Both resonance lines became broader than the
result at 25 K. It is suggested that this phenomenon
resulted from a certain effect on dynamics of implanted
atoms. Furthermore, to discuss the site occupancies of
57Fe ions, the calculation by molecular orbital methods with SCF-Xa and Gaussian procedures is being
performed.
References
1) R. S. Preston and B. J. Zabransky: Phys. Lett. A 55,
179 (1975).
2) M. Nakada et al.: Bull. Chern. Soc. Jpn. 65, 1 (1992).
3) N. S. Kopelev: in Mossbauer Spectroscopy of Sophisticated Oxides, edited by A. Vertes and Z. Homonnay,(Akaderniai Kiado, Budapest, 1997), p. 329.

School of Science, University of Tokyo
Department of Chemistry, Faculty of Science, Science University of Tokyo
Graduate School of Science, Tokyo Institute of Technology

125

RIKEN Accel. Prog. Rep. 34 (2001)

Metabolic Study of Bio-Trace Elements in Pregnant Rats Using
the Multitracer Technique (I)
S. Enomoto, H. Tamano, T. Yanagiya, and R. Hirunuma
It is great of interest to study the transfer of traceelements from the placenta to the fetus because theplacental organ may be regarded as the first environment of human development. Limited information isavailable on the transfer of trace elements from themother to the fetus . Only the transfers of certain traceelements such as Zn and Fe are known, however the uptakes of other trace elements in the placenta and fetus
of a rat during pregnancy remain unknown.
In this paper, the multitracer technique was applied
to study the maternal transfer of trace elements via
the placenta to the fetus.
The radioactive multitracer solution was preparedfrom an Ag target irradiated with a 135 MeV/nucleon
12C, 14N, or 16 0 beam accelerated in the RIKEN Ring
Cyclotron. Chemical separation was carried out, andthen the multitracer solutions were obtained. Physiological saline was added to the radioisotopes to prepare
the radioactive multitracer solution for injection into
pregnant rats.
Seventeen-day-pregnant Wistar rats were used forthis experiment. An appropriate amount of the radioactive multitracer saline was injected intravenously
into the tail. The rats were sacrificed under ether
anesthesia at 3, 12, 24 and 48 hours after injection.
The maternal blood, placentas, fetuses, fetus brains,
and amniotic fluids were removed from the rats andcollected. The activities were determined by ,-ray
spectrometry using highly pure Ge detectors. The results are given in the ratio of the percentage of injected dose to the weight of organs of the pregnant
rats (uptake %/g).
Multitracer was applied to study the distribution of
18 trace elements in the organs and fluids of the 17days-pregnant rats.

126

We examined the time dependence of the uptake
amounts for various elements. From these results , weobserved a large difference in the time dependency ofeach element and it was divided into three groups.
In the first group elements, such as Be, V, Sc, As,
Y, Zr, Tc, Rh, and Ru move to the placenta from thematernal blood and accumulate only in the placenta.
For this first group of elements, the present study revealed high uptake of these elements in the placenta,
with no observable activity in the fetus or the amniotic fluid. The transfers of the first group of elements
occur, demonstrating that these elements hardly penetrate the placental membrane, but the transfers ofthese elements are very low.
In the second group of elements, such as Na, Co,
Ga, Rb, and Sr were transported to the placenta fromthe maternal blood and distributed in the placenta,
fetus , and amniotic fluid. The uptake rates of Na indicated constant accumulation in all tissues, and did
not depend on time after injection. On the other hand ,the uptake rate of Rb increased and those of Co , Ga,
Sr decreased with time after injection in the maternal
blood, fetus, fetal brain and amniotic fluid . Rubidium
has been suggested to be an essential trace element,
but this remains unproven. It is essentially an intracellular ion, physiologically most similar to K and distributed throughout the body in much the same way.
The present study showed uptake of Rb in both placenta and fetus for all times measured. The uptakeof Rb is higher in the placenta than in the fetus. Thissuggests that Rb is able to penetrate the placental barrier. About 43% of Rb in the placenta was transferredto the fetus at 24 hours after injection and the concentration of Rb in the fetus was the same as that inmaternal blood.

RIKEN Accel. Prog. Rep. 34 (2001)

Metabolic Study of BiD-Trace Elements in Pregnant Rats Using
the Multitracer Technique (II)S. Enomoto, H. Tamano, T. Yanagiya, and R. Hirunuma
During pregnancy, there is an increased demand forminerals that are recognized as nutrients either for theformation of the fetus and the products of conception.
The increased demand for these nutritients must be
met through dietary intake or homeostatic responses.
These homeostatic mechanisms may include the use ofbody stores, an increase in absorption of the mineral,
reduction of excretion and/or slowing down of nutrient
utilization or turnover. Some of these homeostatic responses are stimulated the physiological changes that
occur with pregnancy. The utilization and turnoverrate of most minerals during pregnancy is increased
probably because of the synthesis that occurs, butthere have been few studies carried out to examine thisin animals. From our multitracer studies in report (I),
we observed a large difference in the time dependencyof each element and it was divided into three groups.
In this paper, we discuss the biobehavior of the third
grou p of elements.
In this third group, elements such as Mn, Fe, Zn,
and Se were transported to the placenta via maternal
blood and mainly accumulated in the fetus; they were
not detected in the amniotic fluid. The uptake rates ofthese elements correlated with fetal growth. The fetus
requires vast quantities of essential elements for normal
development from the mother across the placenta, because the essential elements have important functions
and are components of various kinds of proteins andtissues.
Although the amount of Mn in the placenta is notas high as that of Zn, the uptake of Mn in the fetus
is very high. The uptake of Mn is approximately 2.8
times higher in the fetus than in the placenta at 24hours after injection, and mainly accumulates in the
fetal brain. Almost of Mn is concentrated in the fetal
brain. The present study revealed that the injection of
Mn also increased Mn transfer through the placenta to
the fetus, and the transfer from placenta to fetus proceeded rapidly. These results suggest that Mn mainly
accumulate in the fetal brain because it is related toneural development. The baby can obtain sufficient

Mn for normal development after birth because thetransfer of Mn from mother to fetus in rats occurs via
the placenta after 18 days of gestation.
The uptake rate of Zn in the placenta is similar tothat in the fetus, reflecting that the same concentrationof Zn in the placenta was transferred to the fetus. After
uptake into the placenta, the Zn is transferred acrossthe cell layer and through other layers of the placenta
and is secreted into the fetal plasma. Finally, it is taken
up into the liver and incorporated into metallothionein.
The rate of transfer of Zn from mother to fetus wasdemonstrated to increase at later stages of pregnancy.
The uptake of Fe in the fetus is higher than that in
the placenta and maternal blood; more than 2.5 times
the concentration of Fe in maternal blood was foundin the fetus in 24 hours after injection. It was concluded that the amount of Fe which the fetus requires
is higher than the requirement of the placenta and thematernal blood. The transfer of Fe from the maternal blood to the fetus via the placenta is related to theconcentration of transferrin, and the fetal Fe is derived
from maternal transferrin.
Selenium plays an important role in the system of defense against peroxidative damage to lipid membranes.
It has high uptake in the placenta, and 33% of the Se
in the placenta was transferred to the fetus within 24
hours of the injection. The uptake of Se in the fetus islower than that of Zn, however, the demand of the fetus for Se is also large. Our results also indicated that
Se is rapidly metabolized by the fetus. Similar to thecase of Mn, it was suggested that the Se transfer frommother to fetus is influenced by the concentration of
Se in the maternal blood.
Based on the results in the reports (I) and (II), we
consider that the placenta is highly selective because
essential elements such as those in the third group arereadily transported across the placental membranes to
the growing fetus, whereas nonessential elements suchas those in the first group hardly penetrated the placental barrier that protects the fetus from toxic effects.

127

RIKEN Accel. Prog. Rep. 34 (2001)

Uptake of Radioactive Elements in Rat Brain Tumor
H. Tamano, S. Enomoto, R. Hirunuma, and A. Takeda
Nuclear medicine techniques, which are noninvasive
methods, play important roles for diagnosis of brain tumors. These techniques can detect tumors by imaging
biochemical and metabolic changes of tumors, unlike
morphological imaging such as X-ray computed tomography (CT) and magnetic resonance imaging (MRI).
18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) has been widely used in the diagnosis of brain tumors. However, FDG PET often fails to
detect brain tumors because of the relatively high uptake of 18F-FDG in the normal brain, in which glucose
is actively utilized. 1) Therefore, the development of atumor-specific imaging agent is necessary for advanced
diagnosis of brain tumors .
Zinc , an essential transition metal for animals andhumans, has three functions in zinc enzymes, i. e., catalytic, coactive (or cocatalytic) and structural. Zinc isnecessary for DNA replication and transcription, andprotein synthesis. This metal may play critical roles in
the regulation of cell division and growth .2) Zinc has
also been ascribed roles in the metabolism and interaction of tumor cells. Dietary zinc deprivation effectively
suppressed the proliferation of transplanted tumors intumor-bearing animals. 3) Judging from the importanceof zinc in cellular proliferation and metabolism, it isconsidered that zinc uptake may reflect the metabolic
activity of tumors. Brain tumors were positively imaged with 65Zn because of the slow turnover of zincin the brain;4) these findings suggest the potential ofusing 69mZn , a short-half-life gamma emitter (half-life,
13.76 h; energy, 439 keY), for the diagnosis of brain tumors by single-photon emission computed tomography(SPECT).
The multitracer technique has the advantage of determining the metabolism of various trace elements under strictly identical conditions. In the present study,
the multitracer technique was applied to determine the
distribution of radioactive elements in rat brain tumor
in order to find radioactive elements that have selective
affinity for brain tumors.
The multitracer solution was prepared from an
Ag target irradiated from a heavy-ion beam of
135 MeY /nucleon accelerated by the RIKEN Ring Cyclotron. Male Fisher rats (nine weeks old) were anesthetized with chloral hydrate in physiological saline
solution and placed in a stereotaxic instrument . C6
glioma cells (2 x 10 5/10 ILl culture media/rat) were injected at a rate of 0.7 ILl/min into the left hippocampus of the rats at the coordinates of -4.7 mm posterior
to the bregam, -3.9 mm lateral to the midline sutureand -6.2 mm from the dura via a microdialysis probe
without a dialyzing membrane using a microinjection

128

pump. Fourteen days after tumor implantation, themultitracer solution (0.3 ml/200 g body weight) was
intravenously injected into the tail vein of the rats.
One hour after the injection of the multitracer solution, the rats were sacrificed after collecting the blood
under deep diethyl ether anesthesia. The brain was
excised and divided into tumor, cerebral cortex, cerebellum and the rest. The radioactivity in each tissue
was measured by ry-ray spectrometry using high-purity
Ge detectors. The assignment of the ry-rays was carriedout on the basis of their energies and half-lives. The
uptake of each radioactive element was given as a percentage of the injected dose per wet weight (% dose/g).
When the multitracer was intravenously injected
into C6-glioma-bearing rats, 15 radioactive elements,
i.e., 7Be, 22Na, 46Sc, 48y, 51Cr, 54Mn, 56CO, 65Z n ,75Se, 83Rb, 85Sr, 88 Zr , 95mTc, 103Ru, and 99Rh, weredetected in the excised brain and/or collected blood
1 h after injection. 65Zn, 83Rb, 54Mn, and 22Na werepreferentially taken up by the tumor, compared toother radioactive elements. Their uptake in the tumor
ranged from 0.5- 0.8% dose/g. The uptake of 65 Zn,
83Rb, and 54Mn in the tumor was 5- 12 times higher
than in any other brain region and significantly higher
than that in the blood. The uptake of 22Na in the tumor was also significantly higher than that in any brain
regions, whereas it was lower than that in the blood.
The uptake of 5 6 Co, 99Rh, 85Sr, 75Se, 51Cr, 46S C , and48y in the tumor ranged from 0.2- 0.4% dose/g, andwas higher than that in any other brain regions. However, the uptake of 56CO, 99Rh , 75S e , 51Cr, and 48y in
the tumor was lower than that in the blood, and theuptake of 85Sr and 46Sc in the tumor was roughly similar to the blood level. 88 Zr , 7Be, 95mTc, and 103Ru
were hardly taken up in the brain.
The present findings demonstrate that zinc, rubidium and manganese are taken up in large amounts by
the tumor in the brain of C6-glioma-bearing rats. Thissuggests the potential using radioactive rubidium andmanganese, in addition to radioactive zinc, for brain
tumor imaging.
References
1) R. Hustinx and A. Alavi: Neuroimaging Clin. N. Am.
9 , 751 (1999).
2) B. L. Vallee and K. H. Falchuk: Phys. Rev .. 73, 79(1993).
3) A. Takeda, K. Goto, and S. Okada: Bioi. Trace Elem.
Res . 59 , 23 (1997).
4) T. Tamano, S. Enomoto, N. Oku, and A . Takeda: submitted to J. Cereb. Blood Flow Metab.

RIKEN Accel. Prog. Rep. 34 (2001)

Metabolic Study of Trace Elements in Se-Excess Rats
R. Hirunuma, H. Tamano, and S. Enomoto
The uptake and distribution of various trace elements in the Se-deficient and Se-excess rats were determined by the multitracer technique, which can beused to evaluate the behavior of many elements simultaneously. This paper describes the synergism and/or
antagonism of Se and some other elements containing
multitracer in the rat's body.
Male Wistar rats bred from the fetal stage on a Sedeficient diet (Oriental Yeast Co., Ltd.) were used inthese experiments as Se-deficient rats. Male Wistar
rats (7 weeks old) were used as normal and Se-excess
rats in the present study.
Multitracer solution containing various kinds of radionuclides was prepared from an Ag target irradiatedwith 14N beam of 135 MeV/nucleon using RIKEN Ring
Cyclotron. The multitracer solution was injected intravenously into each rat. These rats were sacrificed
at several times after injection, and the radioactivity
in their organs was measured using high-purity Ge detectors.
Effects of Se-deficiency on the behavior of Se Fe
and As were evident in various organs. The u~tak~of Se was higher in the brain of Se-deficient rats thanthat of normal ones. The uptake of Se in the liver of
Se-deficient rats was lower than that of normal ones.
In the case of normal rats, the uptake of Se in the liver
was much higher than that in the brain. However, inthe case of Se-deficient rats, the uptake of Se in theliver was almost comparable to that in the brain. It
was reported that a small quantity of Se fed to Sedeficient rats is preferentially absorbed in the brain
than in the liver. 1) Higher uptake of Fe and As wasobserved in the liver of Se-deficient rats than in theliver of normal ones. The concentration of ferritin in
Se-deficient rats was found to be higher than that innormal ones. The increase in Fe uptake by Se-deficient
rats was considered to be due to an increase in theconcentration of Fe-binding proteins, such as ferritin.
Selenium was known to enhance As excretion into the

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bile in rats. 2- 4) Higher uptake of As suggested that bile
excretion of As was decreased by severe Se deficiency.
On the other hand, the behavior of Se, As, Be, andY was affected by Se addition. The uptake of Se in the
blood, kidney, and testicles of Se-excess rats was lower
than that of normal ones. Also, the uptake of As in the
blood of Se-excess rats was lower than that of normal
ones. However, there was no difference in the uptake of
Se and As in the liver between Se-excess and normal
rats. Compared with normal rats, the uptake of Be
and Y in the liver of Se-excess rats was low (Fig. 1).
Selenium is known to be in a competitive or synergistic relationship with several metals. From the present
results on Be and Y, it was newly elucidated that there
was also some interaction between these elements andSe.
References
1) D. Behne et al.: Biochim. Biophys. Acta 966 , 12 (1988).
2) O. A. Levander: Environ. Health Perspect. 19, 159(1977).
3) O. A. Levander and C. A. Baumann: Toxicol. Appl.
Pharmacol. 9 , 98 (1966).
4) O. A. Levander and C. A. Baumann: Toxicol. Appl.
Pharmacol. 9, 106 (1966).

129

RIKEN Accel. Prog. Rep. 34 (2001)

In Vivo Multitracer Detection for Assessment of Dynamics ofElements in Liver and Head of Living Rat
K. Matsumoto, R. Hirunuma, S. Enomoto, and K. Endo
When multitracer solution is intravenously injected
into a living animal, each element in the multitracer isdistributed to particular organs according to its characteristic affinity. Using a ')'-ray detector equippedwith a well-defined slit, collimated ,),-rays from a particular part of the living animal can be obtained. Timecourses of the ')'-ray radioactivities provide informationon the in vivo dynamics of biotrace elements for specific parts of the living animal.
The multitracer was prepared from silver foil. Then,
2 mL of isotonic citrate buffer multitracer solution (pH6.2) was prepared. Six-week-old male Wistar rats wereanesthetized with i.p. injection of pentobarbital. The
rat was fixed to a special plastic rat holder with adhesive tape and placed in the desired position. A slit
(7.5 mm width, 70 mm length, and 50 mm depth) was
placed between the rat holder and a high-purity Ge
semiconducting ')'-ray detector. Immediately after Lv.
administration of 100,uL of multitracer solution, the ')'ray spectra of the liver (n = 4) or head (n = 3) of the
rat were measured. ')'-Ray spectra were accumulated
over 10 min for the liver and 20 min for the head. Dataacquisitions were repeated 6 times for the liver and 4
times for the head. As the standard sample, 10,uL ofmultitracer solution was measured. In this experiment
V, Mn, Co, Zn, As, Se, Rb, Sr, and Y were analyzed.
The distribution of each element was indicated as apercentage of the radioactivity of the measured partto that of the standard sample.
The distributions of As , Sr and Yare relatively low
in the liver and decrease with time (Fig. 1 (A)). These
distributions may depend on the concentration of metals in the blood, and metals may gradually leak fromthe observed area to particular organs through thebloodstream. A smaller fraction of Rb is also found in
the liver but increases gradually with time (Fig. 1 (A)).
It appears that Rb gradually diffuses to organs in theobserved area. Relatively large fractions of V, Mn, Co,
Zn, and Se are found in the liver (Fig. 1 (A) and (B)).
Since relatively high uptake rates of V, Mn, Co, Zn,
and Se in the liver 1- 2 days after i.v. administration
was reported,l-3) the distributions of these elements
are considered to reach a plateau at a very early stage,
and did not change in the time range examined in thisstudy. The distribution of Se in the liver, however, increased at an early stage. Se can be predicted to havea slower distribution rate than V, Mn, Co, or Zn.
Lower distributions of the elements were observedin the head (Fig. 1 (C) and (D)) than in the liver. V,
Sr, and Y, of which the distributions in the head are
higher than those of other elements, may diffuse to the130

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~

Oll--~~~-<(B)~- - Mn- 0 - Co......... Zn--- s(0)~020406080020406080
Time (min)Time (min)Fig. 1. Time course of radioactivity of several elements obtained by the in vivo multi tracer analysis technique.
The radioactivities were measured ((A), (B)) in theliver, and ((C), (D)) in the head of rats.

skull at a very early stage after administration. The
concentrations of V and Y did not change while that of
Sr increased during the early stage. This suggests thatthe distribution rate of Sr may be slower than thoseof V and Y. Co, Se, and As concentrations seem todecrease in the head while Mn, Zn, and Rb concentrations do not change. Since Mn, Zn, and Rb wereobserved in the brain removed from the same rat 48 hr
after administration, these elements may be consideredto accumulate gradually in the brain.
These results suggest that differences in the distribution of elements may mainly reflect preferred accumulation in certain organs and/or tissues in the observed area. Elements injected into a rat distribute
throughout the whole body within at least 30 sec, andmetabolism and excretion begin immediately. The distributions depend on the distribution rate in a very
early stage after administration. Therefore, a shorter
observation time period is required. The distribution level and/or rate of several elements might be influenced by pathological conditions such as oxidative
stress.
References
1) R. Hirunuma et al.: Appl. Radiat. Isot. 48, 727 (1997).
2) R. Hirunuma et al.: Appl. Radiat. Isot. 50, 843 (1999).
3) R. Hirunuma et al.: J. Radioanal. Nucl. Chern. 239,
213 (1999).

RIKEN Accel. Prog. Rep. 34 (2001)

Alleviation of Cadmium Cytotoxicity by Manganese
T. Yanagiya, N. Imura,*l S. Enomoto, Y. Kondo,*2 and S. Himeno*l
Cadmium (Cd) is an environmental pollutant thatcauses adverse effects in organisms, but little is known
about the mechanism of Cd transport. Previously, wedemonstrated that a Cd-resistant cell line (Cd-rB5)
derived from immortalized metallorthionein (MT) nullmouse fibroblasts exhibits a marked decrease in Cd
accumulation, suggesting that the change in Cd transport is responsible for the resistance to Cd in the absence of MT expression.!) Furthermore, the utilization of the multitracer technique has revealed that theuptake of manganese (Mn) in Cd-rB5 cells was also
markedly reduced. 2) Competition studies and kinetic
analyses have indicated that a high-affinity transportsystem for Mn is used for the cellular uptake of Cd inparental cells, whereas this pathway is suppressed in
Cd-rB5 cells, leading to the reduced accumulation of
Cd. 2 )In this study, to explore whether Mn alleviates cytotoxicity of Cd, we examined the effects of Mn addition
to the medium on the cytotoxicity of Cd in Cd-rB5
and parental cells.
Simultaneous addition of MnCh in the medium reduced the cytotoxicity of Cd efficiently in parental cells
but not in Cd-rB5 cells. As shown in Table 1, theIC 50 value of CdCh for parental cells in the absenceof MnCh was 1.6 J..LM, and this value increased up to
18.6 J..LM by the addition of MnCh dose-dependently.
On the other hand, the IC 50 value of CdCh for CdrB5 cells was 25.0 J..LM in the absence of MnCI 2, but
this value was not influenced by the addition of MnCh.
The protective effect of Mn on Cd cytotoxicity inparental cells but not in Cd-rB5 cells suggests that the
reduction of Cd cytotoxicity ' is related to the change

in cellular Cd incorporation by Mn.
Previously, we have shown that the uptake of CdCl 2
was inhibited by the addition of MnCl 2 in parental cells
but not in Cd-rB5 cells, suggesting that the Cd/Mntransport system is not functioning in Cd-rB5 cells. 2)
However, we examined the mutual inhibitory effects of
Cd and Mn uptake only at low dose levels (less than
1.0 J..LM) in the previous study, based on the result thatthe uptake of Mn in Cd-rB5 cells was suppressed only
at Mn concentrations less than 3/LM. Our conclusion
at that time was that there are at least two transportsystems for cellular Mn uptake and that only the highaffinity Mn transport system is suppressed in Cd-rB5
cells. In the present study, however, the addition of
MnCh in the range of 1- 30 J..LM protected against cytotoxicity of Cd in parental cells but not in Cd-rB5
cells. These results implicate that the interaction of
Mn and Cd in terms of their incorporation into cells
is more complicated than expected; at least one of the
low-affinity Mn uptake systems may also be involved in
the Cd uptake, or the high-affinity Mn uptake system
may be responsible for the modulation of Cd toxicity
even when high concentrations of Cd or Mn were applied to cells.
The results of our studies suggest that Mn is involved
not only in the transport of Cd but also in the cytotoxicity of Cd. Further studies are needed to elucidate
the molecular mechanism of Cd and Mn transport.
References
1) T . Yanagiya et al.: Life Sci. 65, PL177 (1999).
2) T. Yanagiya et al.: J. Pharmacol. Exp. Therap. 292,
1080 (2000).

Table 1. Effect of simultaneous addition of MnCh on CdCh cytotoxicity
in Cd-resistant and parental cells.
Parental cells
Mn added in themedium (J.lM)

Cd-rB5 cells

ICso (J.lM) a

Ratio (-fold)ICso(J.lM) a

Ratio (-fold)

0

1.6

1.0

25 .0

1.0

3.6

2.3

22.6

0.9

3

8.4

5.3

22.7

0.9

10

16.9

10.6

22.3

0.9

30

18.6

11.6

21.3

0.9

Parental cells and Cd-rB5 cells were exposed to CdCI 2 in the absence or presence of 1,3, 10 or 30
JlM MnCI 2 for 48 hr, and then the surviving cells were determined by MIT assay.

a The concentration of metals required to kill 50% of the cells as calculated by MTT assay.

* 1 School of Pharmaceutical Sciences, Kitasato University*2

Department of Urology, Nippon Medical School

131

RIKEN Accel. Prog. Rep. 34 (2001)

Tissue Uptake Behavior of Sc, Mn, Co, Zn, Se and Rb in Mice Bred
under Manganese Deficient and Excessive Diets
Y. Kanayama,*1 Y. Yabushita,*1 T. Tarohda,*2 K. Washiyama,*1 R. Amano, and S. Enomoto
It is well known that manganese (Mn) uptake is enhanced under conditions of iron (Fe) deficiency and depressed by large amounts of nonheme Fe. Dietary copper (Cu) also induces decreased Mn uptake and retention. Furthermore, addition of essential and nonessential trace elements to the drinking water can resultin altered tissue uptake of essential trace elements (including Mn) in normal mice. 1) These observations suggest that Mn interacts with other trace elements in
uptake, retention and subsequent tissue distribution.
In this experiment, we examined the interrelationships
between Mn and other elements in mice using a multitracer solution and mice bred under three levels of
dietary Mn concentrations.
The multitracer was obtained from an Ag foil target
irradiated by a 135 MeV /nucleon 12C beam accelerated in the RIKEN Ring Cyclotron according to themethod of Ambe et al. 2- 4 ) The final multitracer solution for injection contained the carrier-free states of
46Sc, 54Mn, 58 Co, 59Fe, 65Zn, 75Se, 83Rb, 85S r and
88Zr in the physiological saline solution (0.9% NaCl in
0.001 NHCl).
The ICR mice (prenatal 16 days) were bred under different Mn-diets until their babies were 3 weeks
old. Mn-diets were prepared with three different
levels of Mn concentration (0.43 ppm, 31.8 ppm and300.4 ppm) , referred to as Mn-deficient, -adequate and-excessive diets, respectively. The multitracer solution
was intraperitoneally (i.p.) injected into the mice (n =5 for each Mn diet). Forty-eight hours after i. p. injection, the brain, thymus, cardiac muscle, lung, spleen,pancreas, kidney, liver , testis, blood, and parietal bone
were excised under ether anesthesia. These organs
were weighed and freeze dried. The dried samples were
subjected to 1'-ray spectrometry using high-purity Ge
semiconductive detectors with reference to an appropriate standard. The uptake behavior was evaluatedin terms of the organ uptake rate (the radioactivity
percentage of injected dose per gram, %dose / g).
Figure 1 compares the organ uptake behavior of
46S c , 54Mn ' 5. 8CO ' 65Zn , 75S e , and 83Rb tracers in
the mice bred under Mn-deficient, -adequate and-excessive diets. These six elements were traced simultaneously in all samples. The 54Mn uptakes in allorgans of Mn-deficient mice were found to be significantly higher than those of Mn-adequate mice. However, there were no significant differences between Mnadequate and excessive mice. As noted for the other elements (Sc, Co, Zn, Se, and Rb) , the 58CO uptake rates
in lung, spleen, blood , and kidneys of Mn-deficient
mice were higher than those of Mn-adequate mice.
Furthermore, significant differences were also found ino Mn-deficient

I1Q Mn-excessive

KI

U

TE DO

DL 1B LV eM SP PA KI

U

TE DO

DL 1B LV eM SP PA KI

U

TE DO

DL 1B LV eM SP PA KI

U

TE DO

DL 1B LV CM SP PA KI

U

TE DO

DL 1B LV eM SP PA KI

U

TE DO

DL 1B LV CM SP PA

Fig. 1. Organ uptake rates of 54Mn, 46Sc, 58CO, 65 Zn, 75Se, and 83Rb in mice bred under three different
Mn-diets. Symbols indicate as follows: BL: blood; TH: thymus; LV: lung; CM: cardiac muscle; SP:spleen; PA: pancreas; KI: kidneys ; LI: liver; TE: testes; BO: bone. Statistical analysis of data was byt-test: *p < 0.05 , **p < 0.01, ***p < 0.005 , ****p < 0.001. ICR mice were bred under three different
Mn-diets, which are deficient (Mn 0.4 ppm), adequate (Mn 31.8 ppm) , and excessive (Mn 300.4 ppm)
diets (n = 5 for each group).

*1
*2

132

School of Health Sciences, Faculty of Medicine, Kanazawa
University
Graduate School of Natural Science and Technology,
Kanazawa University

the 65Zn uptake rates in thymus, lung, spleen, andlive~. On the other hand, comparing Mn-adequate to
Mn-excessive mice, there were few differences in all uptakes of Sc, Co, Zn, and Se (except the 46Sc and 75Se
bone uptake rates). In all 83Rb uptakes, no significant
difference was observed among the three different mice.
In conclusion, the alteration of Mn concentration in
the diet influences not only the Mn uptake but also the
Sc, Co, Zn, and Se uptakes in various organs except thebrain. 5)

References
1) J. C. K. Lai et al.: in Manganese and Its Role in
Biological Processes ( Metal Ions in Biological Systems,
Vol. 37), edited by A. Sigel and H. Sigel (Marehel
Dekker, New York, 1999) , p. 123.
2) S. Arnbe et al.: Chern. Lett. 1991, 149.
3) S. Arnbe et al.: Anal. Sci. 7 , Suppl., 317 (1991).
4) S. Arnbe et al.: J. Radioanal. Nuel. Chern. 195, 297(1995).
5) Y. Yabushita et al.: RIKEN Aeeel. Prog. Rep. 34, 134(2001) .

•133

RIKEN Accel. Prog. Rep. 34 (2001)

Brain Regional Uptake Behavior of Sc, Mn, Co, Zn, Se, and Rb in
Mice Fed Mn-Deficient and Excessive Diets
Y. Yabushita,*l Y. Kanayama, T. Tarohda,*2 K. Washiyama,*l R. Amano, and S. Enomoto
Manganese (Mn) is an essential trace element, and
it is widely distributed in the tissues of animals. Deficiency of manganese during embryonic development
leads to congenital ataxia, and its excess affects thecentral nervous system, impairing cognitive functions
and motor activity.!) It is thought that these several
symptoms are caused by influences of various elementelement interactions rather than by influences of a single element. However, little is known at present about
the interrelationships between Mn and the other elements in the brain. In the present research, we determine the brain regional uptakes of multitracer inmice fed three kinds of diets with different Mn concentrations to obtain some information on the biologicalinteractions of Mn with trace elements.
An Mn-deficient diet was purchased and Mnadequate and excessive diets were prepared by adding
MnC0 3 to the Mn-deficient diet. ICR mice were fed
the Mn-deficient, Mn-adequate or Mn-excessive dietswith pure water from prenatal 16 days. Natal baby
mice were bred to 3 weeks with their dams. A multitracer solution containing 7Be, 46Sc, 54Mn, 59Fe, 58Co,
65Zn, 75S e , 83Rb, 85S r , 88y, and 88Z r was injected in-traperitoneally into 3-week-old male mice. Forty-eight
hours after injection, they were sacrificed under ether
anesthesia. The brain was excised and separated into
eight regions. These separated brain regions were measured using , -ray spectra with high pure Ge detector
and evaluated in terms of "brain regional uptake rate(% dose/g)."On the basis of the results, the multitracer solution
enabled a simultaneous tracing of 54Mn, 46SC, 58Co,
65Zn, 75S e , and 83Rb in all brain regions. Figure 1
shows their brain regional uptakes in Mn-deficient,adequate and excessive mice. The 54Mn uptakes ofMn-deficient mice were clearly higher than those of
Mn-adequate mice. However, no significant differences were observed between Mn-excessive and adequate mice. On the other hand, no significant differences among three different diets were observed forall other tracers. As compared among brain regions,
54Mn, 58CO, 65Z n , and 83Rb were distributed evenly
in all regions. However, 75Se and 46S c were regionspecific and concentrated in certain brain regions. The
75 Se uptake rate was significantly higher in the cerebellum and the olfactory bulb than that in the othero Mn O.4ppm • Mn 31.8ppm
2.50

54

2.00
bJ)
~ 1.50
~

Q

-=

1.00

*

2.50 , - - - -- -- - - - r - - - - - - - - - - , 0.25

Mn

* *

**
*

*

- - - - + - - -- ----j 0.20

2.00

*

*

1.50 1---- -- -1.00 I - - --= 0.000.00

CC ST ill HY MB CD PM OB
3.00

2.00

r-

__-+-----.+-ifa-l 0.05

t-.........._.u...._....u__...L.L..II-.w'__u....&....II..........._... 0.00

~

7S

Se

83

H

I II
I I
ill

I-

HY MB CB PM OB
T

Rb

4.00

1.00

h

0.50

H

2.00
0.00

CC ST ill HY MB CB PM OB

CC ST ill HY MB CB PM OB

Fig. 1. Brain regional uptakes of Mn, Sc, Co, Zn, Se, and Rb in Mn-deficient , adequate and excessive
mice. CC: cerebral cortex; ST: corpus striatum; HI: hippocampus; HY: thalamus and hypothalamus;
MB: midbrain; CB: cerebellum; PM: pons and medulla; OB: olfactory bulb. Each bar and line
represents the mean ± S.D. for five animals. Asterisks indicate significant differences (* p < 0.05,** P < 0.01) from Mn-adequate mice.
*1

*2

134

l

~

~

0.00

CC ST ill HY MB CD PM OB

CC ST
6.00

1.50

0.00

- 1 1 1 - - - - - - - 1 0.15

CC ST ill HY MB CB PM OB
2.50

5~CO

--l'::-""'f't--ll U__...--'f'------I 0.10

0.50

~ 0.50gJ Mn 300.4ppm

School of Health Sciences, Faculty of Medicine, Kanazawa
University
Graduate School of Natural Science and Technology,
Kanazawa University

regions, and the 46Sc uptake rate was also higher inthe midbrain.
These findings suggest that both Mn-deficient andexcessive states do not markedly influence the brain
uptake behaviors of the other trace elements in mice
fed diets with Mn concentrations from 0.4 to 300.4 ppm
in this experiment, although some interactions wereclearly observed in the organs except those in the brainof identical mice. 2)

References
1) R. M. Leach, Jr . and E. D. Harris: in Handbook of
Nutritionally Essential Mineral Elements, edited by B.
L. O'Dell and R. A. Sunde (Marcel Dekker, New York,
1997), p. 335.
2) Y. Kanayama et al.: RIKEN Accel. Prog. Rep. 34, 132(2001).

135

RIKEN Accel. Prog. Rep. 34 (2001)

Biobehavior of Multitracers in Brain of 1-, 4- and 8-Day-Old
Normal MiceT. Tarohda,*1 Y. Yabushita,*2 Y. J(anayama, R. Amano, and S. Enomoto
Conveniently, the multi tracer contains simultaneously both essential and nonessential trace elements ina salt-free and carrier-free state. We have been interested in the investigating the brain functions of essential elements and the neurotoxic effects of nonessential
elements. In the previous report, we examined multitracer behavior in the brains of 1-, 3- and 8-week-old
mice. I) In this work, we continuously focused on thestudies of multitracer uptake, transportation and retention in the brain during postnatal development.
A carrier-free multitracer was obtained from an Ag(purity: more than 99.99%) target irradiated with a
12C beam of 135 MeV /nucleon in the RIKEN Ring Cyclotron. The multitracer was separated and preparedaccording to the method of Ambe et al. 2- 4 ) at the Radioisotope Center of Kanazawa University. The multitracer solution for injection was prepared as a slightly
acidic physiological saline solution.
Sixty normal ICR mice used in this experiment weredivided into three groups according to age: 1-, 4- and8-day-old groups. An appropriate amount of the multitracer solution (0.1 ml/5 g mouse weight) was injected
intraperitoneally (i.p.) into each mouse. The mice
were dissected and perfused with 0.9% NaCI solution
under ether anesthesia 6, 12, 24 and 48 hours after
i.p. injection. Brain samples were excised, and thenweighed immediately and then freeze-dried. The driedsamples were subjected to , -ray spectrometry using
pure Ge detectors. The uptake behavior was evaluatedin terms of brain uptake rate, namely the radioactivity percentage of injected dose per gram of the brain
of interest (% dose/g).
The multitracer technique enabled simultaneous
tracing of the nine elements, Sc, V, Mn, Co, Zn, Se, Rb,
Ru, and Rh, in the identical brain samples and an accurate comparison of their biobehavior. Figure 1 compares the brain uptake rates in the 1-, 4- and 8-day-old
normal mice 6, 12, 24 and 48 hours after i.p. inj ection.
The brain uptake rates for these elements in the I-dayold mice were the highest among those of elements inall age-groups examined. The uptake rates of 1- to 8day-old mice are very higher than the uptake rates of
21- to 56-day-old mice, as reported previously. 1) Thesehigh uptake rates are presumably related to the manner of brain growth during neonatal development (theweight of a I-day-old brain increased by approximately
four times over in the three weeks after birth, as shown
*1

*2

136

Graduate School of Natural Science and Technology,
Kanazawa University (Asanagawa General Hospital)
School of Health Sciences, Faculty of Medicine, Kanazawa
University

a - dey - old

4-dey-old, 00.0
"iilI
~

]'0.0
~

.-t.bi

.,.y

$

s-

1\.

""'- ,un.

~~~fl 1.0I./

1-~_ I .

i.,....

<r::> 0 , 'j lflOii

o

10

20

30

40

50 0

'0

Tim 0 (h rl

20

30

40

50 0

Tim. (hr)

'0

20

--

r-r-...

30

40

50

Tim. (hr)Fig. 1. Brain uptake rates for Sc, V , Mn, Co , Zn, Se, Rb,
Ru, and Rh in normal mice 6, 12, 24 and 48 hr after i.p.
injection of the multitracer solution. Each uptake rate
represents the mean value ±S.D. obtained f0r five mice.

0.6
-I

0.5

~

0.4

.:d

0.3

Q)

0.2

.~
~

0.1

II
T!

1'1'

/

..,-

J

o
o

10

20

30

40

50

60

Age (day)Fig. 2. Developing brain weight of normal mouse.

in Fig. 2). The high uptake rate may also be attributed
to the high metabolic rate and the imperfect formationof the blood-brain barrier in infancy. Moreover, there
appear to be two uptake patterns in brain; one seems
to be increasing with time, as shown in Rb, Sc, Mn,
Se and Zn patterns, and the other seems to increase at
first and decrease gradually with time as shown in Co ,V, Ru and Rh patterns. These patterns were found to
be more distinct in the aged brain. This phenomenon
may represent a classification of these two groups, owing to the necessity of the different elements in thebrain. As to Rb and Sc, Rb may uptake into brain
as a substitute for K, but Sc behavior has yet to be
determined.
References
1) T. Tarohda et al.: RIKEN Accel. Prog. Rep. 33 , 118(1999).
2) S. Ambe et al.: Chern. Lett. 1991 , 149.
3) S. Ambe et al.: Anal. Sci. 7 , Suppl. , 317 (1991).
4) S. Ambe et al.: J. Radioanal. Nucl. Chern. 195, 297(1995).

RIKEN Accel. Prog. Rep. 34 (2001)

Effect of Sodium Iron Ethylendiaminetetraacetic Acid Intake on the
Uptake of Trace Elements in Anemic Rats
K. Igarashi,* H. Inage,* Y. Nakanishi, * R. Hirunuma, S. Enomoto, and S. Kimura*
Iron deficiency is one of the major micronutrient deficiencies. With diets that mainly consist of cereals orvegetables, which contain inhibitors of iron absorption,
in developing countries, there is a high prevalence ofiron deficiency and anemia. One method of improving
iron deficiency is by food fortification , which is usually considered the most sustainable approach. Fishsauce is considered as a good vehicle for iron fortification in Asian countries such as Vietnam. Sodium Iron
Ethylendiaminetetraacetic Acid (NaFeEDTA) is stable during processing and storage , and is also a highlybioavailable form of iron recommended as an iron fortificant. Davidsson et al. reported that NaFeEDTA
dose not reduce the absorption of Zn, although there
is a possibility that EDTA might bind to other metals
and change the state of these metals. Iron bioavailability depends on food components. Tannic acid, whichis contained in vegetable foods, is an inhibitor of ironabsorption. We thus select tannic acid as an inhibitor
to study.
In this work, we studied the inhibitory effect of tannic acid on iron absorption and various elemental uptakes from NaFeEDTA or ferrous sulfate (FS) and amultitracer additive diet on anemic rats .
Three-week-old Wistar male rats were purchasedfrom Charles River Japan, Inc. and were housed instainless steel cages. They were made anemic throughtheir diets. The composition of the diets is shown in
Table 1. The diets, mineral and vitamin supplements
were prepared in accordance with the recommendations of the American Institute of Nutrition (AIN-93).
Iron was excluded from the mineral supplement. Ferrous sulfate was used as a control. Three days before
the experiment, rats were divided into four groups by
dietary control. After 5 weeks feeding, rats were given
an experimental diet and orally administered tannic
acid or saline. The rats were orally administered adose of 2 mg tannic acid. Rats were sacrificed 3, 7,
24 and 48 hours after administration of tannic acid orsaline. Organs such as liver, spleen, kidney and bone
were separated and blood was collected, centrifugedinto plasma and clot. The radioactivities of their organs and blood were measured using high-purity Ge
detectors.
The concentration of hemoglobin in anemic rats ,9.4 ± 0.13 g/dl, was lower than that in normal controls, which had concentrations from 13 to 17 g/ dl. In
this study, the multitracer contained the following elements: Na, Sc, Mn, Fe, Co, Zn, As, Se, Rb , Sr, Zr,
Graduate School of Human Life Sciences, Showa Women 's
University

Tc, and Rh. The uptake rates of Fe and Zn in anemic
rat liver are shown in Fig. 1.
The uptakes of Fe and Zn for every group increased
with time. In the case of Fe uptake, tannic acid had inhibitory effects on the FS additive diet. On the other
hand , tannic acid had few suppressive effects on the
Table 1. Composition of iron deficiency diet (ID).
In~redient (%)

ID

Casein
L-Cystine

14
0.18

14
0.18

14
0.18

Corn starch
62.1
Sucrose10
Soy bean oil
4Cellulose
5
Mineral mix [Fe (-)] 3.5
Vitamin mix
1
Choline bitartrate 0.25

38.19
10
4
5
27.38
1
0.25

38.19
10
4
5
27.38
1
0.25

FS

NaFeEDTA++

Experimental diet A Experimental diet B

1Iron compound 2
Multitracer

1 Corn starch was replaced with mineral mix in experimental diet.
2352mg Fe/kg diet as FS or NaFeEDTA was added (eachrat was given iron compounds at a dose of 0.5 mg Fe).

Fe

tanninsaline0.5.- 0.5~~~e 0.25

0.25

~

..:i:

~

o

o
o

24

48

o

24

48

o

24
Time (h)

48

Zn
0.5

.- 0.5~~'-'~e 0.25

i

0.25

o

o
o

24
Time (h)48

Fig. 1. Uptake rates of Fe and Zn in liver of anemic rats on
the FS (X) or the NaFeEDTA (_) diet. Each datum inthe figures represents the mean value ± S.E. obtained
from at least eight preparations.

137

NaFeEDTA additive diet. Forty-eight hours after administration, about 22.0% of Fe uptake for the FS dietand about 8.0% of that for the NaFeEDTA diet had decreased. The biodistribution of Zn in anemic rat liver
yielded similar results to the Fe uptake. Although Zn
uptake for the FS diet was inhibited by 60.0%, that on
the NaFeEDTA diet was inhibited by only 16.5% fromtannic acid 24 hours after administration. However,the uptake rates of Fe did not show a large difference
between the FS and the NaFeEDTA diets with or without tannic acid. Zinc uptake on the FS diet without
tannic acid was higher than that on the N aFeEDTA
diet without tannic acid 24 and 48 hours after administration. In the case where tannic acid was added,138

the uptake rates of Zn on the FS and the NaFeEDTA
diet had similar levels. These results suggested that
NaFeEDTA differed little from FS in the terms of theuptake of Fe with tannic acid and did not affect theuptake of Zn into the liver.
There is great interest in food fortification using
NaFeEDTA. The biodistribution of various other elements and other tissues from rats on the FS and the
NaFeEDTA diets with or without tannic acid are currently under data analysis. Our results indicate thatthe multitracer technique is a convenient tool for obtaining information on the behavior of various traceelements in nutritional research .

RIKEN Accel. Prog. Rep. 34 (2001)

Study on Distribution of Multitracer in PartiallyHepatectomized Rats
A. Nakayama,* H. Yasui,* H. Sakurai,* R. Hirunuma, and S. Enomoto
The multitracer technique has been developed to simultaneously analyze the dynamic behavior of traceelements in animals and plants. In this study, we investigated the effects of liver regeneration on the intestinal
absorption and tissue distribution of trace elements innormal rats. The time courses of radioactivity of themultitracers in organs were evaluated using the distribution ratio. Accumulation of trace elements in thetissues significantly changed in the liver and small intestine of partially hepatectomized rats. These results
suggest that the liver regeneration may alter the intestinal absorption and hepatic distribution of several
trace elements in terms of the requirement of endogenous elements in cell division.
In general, the liver has been considered to function normally owing to its potential ability to maintainhomeostasis even if two thirds of it is lost. In addition,
the regeneration speed of the liver is so fast that it recovers its normal size within almost 10 days after two
thirds of it is removed. In the regeneration period ,hepatocytes induce cell division to cover the decreased
primal hepatic functions. Since the intestinal absorption of nutrition including trace elements affects protein syntheses in the liver, and nutrients absorbed fromthe gastrointestinal tract are transferred to the liver
through the portal vein, the reduction of the hepaticfunctions changes the distribution of trace elements inthe entire body. Thus, we examined the distributionof essential trace elements in the liver, kidney, and intestines of rats that had been partially hepatectomized
by orally administering multitracer elements to elucidate the relationship between the liver regenerationand global disposition of trace elements.
Male Wistar rats (body wt. ",,250 g) were divided
into three groups; normal, and 1 h or 5 days after
the 70% hepatectomy. A multitracer solution containing the radioisotopes of 20 elements was preparedfrom an Ag target irradiated by a heavy-ion beam of
135 MeV/nucleon accelerated by the RIKEN Ring Cyclotron. The multitracer solution was orally administered to the rats (0.5 ml/rat). The rats were sacrificed 1, 3, and 6 h after the administration, and blood
samples were collected and selected organs (liver, kid.,.
ney, and small intestine) were removed from the rats
in each group (n = 4). The radioactivity levels in the
blood, liver, kidney, and intestine were measured by "(ray spectrometry. The observed ,,(-rays were analyzed
in terms of their energies and half-lives. The individual behaviors of Be, N a, Ca, Sc, V, Cr, Mn, Fe, Co,
Zn, As, Se, Rb , Sr, Y, Zr, Tc, Ru, ~nd Rh were examined. The obtained time courses for the amount ofeach trace element in each organ were evaluated basedon the distribution ratios (% dose/g wet weight of thetissue).
The amounts of the 19 trace elements accumulated
in the tissues were simultaneously determined on thebasis of the radioactivity. The effects of 70% hepatectomization on the accumulation of the trace elements
were marked in the liver and small intestine. Intestinal
absorption of Fe and As in hepatectomized rats was enhanced higher than that of normal rats, whereas thatof N a and Ca was unchanged between the normal andhepatectomized rats, and that of Zn, Mn, Cr, and V
decreased in the hepatectomized rats compared withthat of normal rats. In addition, the hepatic uptakeof Na, Zn, Se, As, and V significantly increased in thehepatectomized rats. These results suggest that liver
regeneration alters the intestinal absorption and hepatic distribution of several trace elements. On the basisof these results, further studies on the relationship between trace element requirements and hepatocyte division will provide important information for analyzing
the features of several diseases in terms of trace elements.

Department of Analytical and Bioinorganic Chemistry,
Kyoto Pharmaceutical University

139

RIKEN Accel. Prog. Rep. 34 (2001)

Uptake of Trace Elements in Rat Lens
T . Nabekura,* T. Minami,* R. Hirunuma, S. Enomoto, and Y. Ito*
Transparency is a remarkable and unique characteristic of lenses, and is a basic prerequisite for normal
visual acuity. Lens transparency is conditioned by cellular structure, protein structure and constitution andthe concentration of electrolytes. To maintain transparency, protective mechanisms, such as glutathione
peroxidase and superoxide dismutase, are well developed.
Metals are known to act as activators and/or inhibitors of various enzyme reactions. However, the roleof trace elements in lenses has not been fully investigated. The multitracer technique was established at
RIKEN and has been successfully applied to many biological systems for comparing the behavior of a number of elements under strictly identical experimental
conditions. In the present study, the multitracer technique was applied to the determination of the uptakeof trace elements in the lenses of adult and sucklingrats.
The radioactive multitracer solution was preparedfrom silver foil irradiated with a 14N beam of
135 MeV /nucleon from the RIKEN ring cyclotron.
Lenses of adult (6-week-old) and suckling (13-day-old)male SD rats were carefully removed by a posterior
approach. The lenses were precultured in phosphatebuffered saline (PBS) for consistency at 37°C under
5% CO 2 /95% air atmosphere . After precultivation,
the lenses were checked under a microscope, and clear
and nondamaged lenses were used in subsequent experiments. The lenses were transferred to 3.9 mL offresh PBS in 30-mm-diameter dishes. Saline solution (0.1 mL) containing multitracer was added to themedium, and the lenses were cultured at 37°C under 5% CO 2 /95% air atmosphere. The incubation was
stopped by removing the lenses from the PBS medium
containing multitracer and washing then 3 times in
4 mL of ice-cold PBS. The radioactivities were determined by ,-ray spectrometry using a pure germanium
detector. Identification and determination of nuclides
were performed on the basis of their energies and halflives and the peak areas of their ,-ray spectra.
Table 1 shows the uptake of trace elements in adultand suckling rat lenses exposed to multitracer for 4 h.
Be, Sc, V, Mn, Fe, Co, As, Se, Rb, Sr, Y, Zr, Ru andKinki University

140

Table 1. Uptake of trace elements in adult and suckling
rat lenses exposed to multitracer for 4 h.
Element

Adult rat lens(% / mg lens)

Suckling rat lens(% / mg lens)Be

0.D1744:1:0.oo13

0.01398±0.0015

Sc

0.01748:1:0.0025

0.01340:1:0.0020

V

0.02017:1:0.0031

0.D1460±0.0020

Mn

0.03380:1:0.0014

0.02626:1:0.0031

Fe

0.02153:1:0.0012

0.01527:1:0.0019
0.03320:1:0.0050

Co

0.03453:1:0.0018

As

0.01702:1:0.0025

0.01309:1:0.0013

Se

0.03865:1:0.0025

0.05009:1:0.0045

Rb

0.01647:1:0.0007

0.03156±0.0038

Sr

0.04432:1:0.0021

0.02222:1:0.0028

Y

0.01544:1:0.0021

0.01111:1:0.0011

Zr

0.01802:1:0.0032

0.0122l:t0.0014

Ru

0.04082:1:0.0016

0.02935:1:0.0036

Rh

0.03890:1:0.0022

0.02913:1:0.0037

Data represent mean :l:S.E. of four measurements.

Rh were detected. However, uptake rates of trace elements in lenses differed for each element and in adultand suckling rats. Uptake of Se and Rb were higher
in the lenses of suckling rats than adult rats (significant different; p < 0.05) . In contrast, uptake of Sr byadult rat lenses was higher than by suckling rat lenses(p < 0.05), and Co and As uptake showed comparable
levels in adult and suckling rat lenses (p > 0.1). In general, it may be easier for suckling rat lenses to absorb
elements from outside, because the barrier function ofsuckling rat lenses has not fully matured. However, ourresults showed that some elements were not absorbed
by suckling rat lenses to any greater extent. Therefore,
uptake of trace elements in rat lenses should be conducted not merely by passive diffusion, but also somespecific mechanism of absorption and/or excretion ofcertain elements. Furthermore, the development affects the transport of trace elements into rat lenses.
The present study suggests that different mechanisms,
depending on the development , act to transport traceelements into lenses.

RI KEN Accel. Prog. Rep. 34 (2001)

Effect of Administration Methods of Multitracer Solution on Uptake
Rates of Cobalt and Other Trace Elements in Zn-Deficient MiceT. Ohyama,*l T . Yoshida,*l H. Maetsu,*l M. Noguchi,*2 H. Suganuma,*l R. Hirunuma,
S. Enomoto, T. Omori,*l and M. Yanaga*l
Cobalt is one of the essential trace elements in livingorganisms. Each male adult contains 1.1 mg of thiselement. It is absorbed in the intestine and excreted
mainly in urine. This element is mainly incorporated
into cobalamines, such as vitamin B 12 , which is an
important organic compound for maintaining normal
metabolism, growth and functioning as a coenzyme inliving organisms.
Previously, we investigated the biobehavior of someessential trace elements, such as Mn, Fe, Co and Zn,
in mice using instrumental neutron activation analysis(INAA) and the multitracer technique. 1- 6 ) The results
obtained with INAA revealed that Co concentrations
in all organs and tissues of Zn-deficient mice (Zn-def.
mice) were higher than those of control mice. 1- 3 ,6) The
ratio of Co concentrations in various organs and tissues of Zn-def. mice to those of control mice increased
until a 3-week treatment period with a Zn-deficient
diet from 8 weeks of age and an additional increasein the ratio was not observed in the longer treatment
period. 6 ) We considered that the reason for the increase in the Co concentration in Zn-def. mice was theincrease in the Co uptake rate in various organs and tissues. An increase in the Co uptake rate was expected
in Zn-def. mice in the less than 3-week treatment period with the Zn-deficient diet. Therefore, the multitracer technique was applied in order to determine
the uptake rate of Co and other trace elements in Zndef. mice which were treated with a Zn-deficient dietfor 1 or 3 weeks . However, the results for multitracer
experiments did not show a significant difference in
the Co uptake rates between Zn-def. mice and control
ones. 4 ,5) In these multitracer experiments, intraperitoneal injection was used as the administration methodof multitracer solution into each mouse. The uptake
rates obtained by this administration method were notreflective of the change in mucosal functions upon absorption of trace elements in the intestine under a Zndeficient state. If the increase in the Co concentrationin Zn-def. mice depends on the amount of Co absorbed
in the intestine, it is necessary to investigate the effectof the administration method on the amount of Co
absorbed. Therefore, in the present work, the administration method of multitracer solution was changed
to oral administration.
A multitracer solution was prepared from a*1*2

Radiochemistry Research Laboratory, Faculty of Science,
Shizuoka University
Department of Biology and Geosciences, Faculty of Science,
Shizuoka University

Ag target irradiated by a heavy-ion beam with
135 MeV/nucleon accelerated by the RIKEN Ring Cyclotron. The multitracer solution for oral administration was adjusted to pH 3 with diluted hydrochloric
acid. Other experimental procedures, except for theadministration method , were the same as those in ourprevious works. 4 ,5)Figure 1 shows the uptak~ rates of Zn and Co invarious organs and t issues of Zn-def. mice and control
ones. As shown in Fig. 1, Co uptake rates of Zn-def.
mice were higher than those of control ones. This result showed the increase in the amount of Co absorbed
in the intestine in the Zn-deficient state. This may be
one of the reasons for the increase in the Co concentration in the Zn-deficient state. On the other hand,
Zn uptake rates of Zn-def. mice were also higher thanthose of control ones. The postulate that Co shares acommon intestinal mucosal transport pathway with Fe
was reported .7 ) In the present case, the result suggests
the existence of a common absorption pathway of Zn
and Co.
For the other elements, such as Fe and Mn, there
were no differences in the uptake rates between Zndef. mice and control ones. On the other hand , Fe andMn concentrations of Zn-def. mice were higher thanthose of control ones in the case of the more than 6week treatment period with the Zn-deficient diet. 6 ) Ina more severe Zn-deficient state, the change in uptake

lOa

lOa

100

KidneyLiver

Ii.g 10

~

~

::::

10

I

.!l
~

101
:>

~

0.1
0.01

0.01

a

20

40

60

Pancreas

~

10

~

0.1

O.oJ

80

lOa

a

20

40

60

80

100

a

20

40

60

80

100

80

100

a

20

40

60

80

100

o

20

40

60

80

100

Tim./ h

a

20

40

60

-lr Zn (Zn-def. mice)-0- Co (Zn-def. mice)..... Zn (Control mice)..... Co (Control mice)

Fig. 1. Zn and Co uptake rates in various organs and tissues
after oral administration of multitracer solution (I-weektreatment period with Zn-deficient diet) .

141

rates of these elements, such as Mn, Fe and Co, in
Zn-def. mice might be observed.
References
1) M. Yanaga, M. Iwama, K. Takiguchi, M. Noguchi, andT. Omori: J. Radioanal. Nucl. Chern. 231 , 187 (1998).
2) M. Yanaga, M. Iwama, K. Shinotsuka, K. Takiguchi,
M. Noguchi, and T. Omori: J. Radioanal. Nucl. Chern.
243, 661 (2000).
3) M. Yanaga, H. Wakasa, T. Yoshida, M. Iwama, K.
Shinotsuka, M. Noguchi, and T. Omori: J. Radioanal.

142

Nucl. Chern. 245, 255 (2000).
4) T. Ohyama, T. Yoshida, M. Iwama, M. Yanaga, M.
Noguchi, T. Omori, R. Hirunuma, and S. Enomoto:
RIKEN Accel. Prog. Rep. 33, 118 (2000).
5) T. Ohyama, M. Yanaga, T. Yoshida, H. Maetsu, M.
Noguchi, H. Suganuma, T. Omori, R. Hirunuma, and S.
Enomoto: J. Radioanal. Nucl. Chern., to be published.
6) M. Yanaga, M. Iwama, T. Yoshida, H. Wakasa, T.
Ohyama, M. Noguchi, and T. Omori: to be published.
7) A. B. R. Thomson, L. S. Valberg, and D. G. Sinclair:J. Clin. Invest. 50 , 2384 (1971).

RIKEN Accel. Prog. Rep. 34 (2001)

The Absorption of Divalent Cations in Digestive Organs
S. Yoshida,* M. Masuda,* M. Nakayama,* M. Yamasaki,* R. Hirunuma,
S. Enomoto, and H. Morikawa*
During pregnancy, the maternal mineral metabolism
changes dramatically to satisfy the fetal demand. Intestinal absorption is one of the most essential aspectsof mineral metabolism. The purpose of this study is
to clarify the principal portion(s) in the intestinal loop
responsible for the absorption of calcium and magnesium in a pregnant state.
A multitracer was produced by irradiating a titanium target with a 14N-beam of 135 MeV nucleon fromthe RIKEN Ring Cyclotron. This contains 28Mg, 47Ca
and other radioisotopes. The multitracer solution is
dissolved into a buffer solution. Nine-week-old female rats (nonpregnant state and age-matched pregnant rats in the 6th, 13th, 20th day of gestation) wereused for the experiment.
The rats were fasted overnight and then anesthetizedwith pentobarbiturate. Segments of the duodenum, jejunum, ileum and colon of 6 cm length were isolated.
Each specimen was everted to prepare a sac with mucosa on the outside. Each gut sac was filled with 600 J.lI
of multitracer solution and then immersed in 10-ml of
the buffer solution and incubated with bubbling of 95%
O 2 and 5% CO 2 at 37°C for 90 minutes. After incubation, 300 J.lI of the solution from the serosal side,and 3 ml from the mucosal side were removed. The
activity of each tracer in the sample was determinedby gamma-ray spectrometry using high-purity Ge detectors. Data were expressed as the 81M ratio (theserosal side content is indecated as 8 and the mucosalside content as M). An 81M ratio greater than 1.0
can be considered as a mechanism of active transport
jejunum

duodenum
4.0of the minerals from the mucosal into the serosal side.
The 81M ratio of Ca in the duodenum was significantly greater than 1.0. On the other hand, the SIM
ratio of Mg was significantly greater than 1.0 only inthe colon, as shown in Figs. 1 and 2. In short, it is suggested that the active transport of Ca from the mucosalside into the serosal side exists only in the duodenum,and that of Mg only in the colon. On the 6th and 13thdays of gestation, the 81M ratios of Ca in the duodenum were the same as those in the nonpregnant state.
However, on the 20th day of gestation, the SIM ratios
in the duodenum increased, which were significantly
higher than those in the nonpregnant state. This indicates that the absorption of Ca in the duodenum
increases late in the course of pregnancy.
On the other hand, there were no intestinal sitesthat presented a significant increase of more than 1.0
in the S I M ratio of Mg during gestation. On the 13thand 20th days of gestation, the 81M ratios in the colon
were significantly lower than those in the nonpregnant
state. These data suggest that the active transport ofMg observed in the colon of nonpregnant rats was notpresent during gestation.
Other authors 1,2) also reported that the 81M ratioof Ca in the duodenum was greater than 1.0. The
81M ratios in pregnant animals were reported to increase compared with those in nonpregnant subjects. 2 )The results of the present study on Ca were consistent
with these reports. On the other hand, there are few
previous reports about the intestinal absorption of Mg
in which the everted gut sac and the single RI tracer
colon

ileum

*

3.5
3.0

.,

.o

2.5

E!! 2.0~

tis 1.5
1.0

0.5

o
(n)

non 6d
-preg
(4)
(4)

13d

20d

(4)

(4)

non
-preg
(4)

6d

13d

20d

(4)

(4)

(4)

non
6d
-preg
(4)
(4)

13d

20d

(4)

(4)

non
-preg
(4)

6d

13d

(4)

(4)

20d

(4)

M± S.D.

* p 0.05<

Fig. 1. The SIM ratio of calcium.
Department of Obstetrics and Gynecology, Nara Medical
University

143

duodenum

jejunum

colon

ileum

1.6
1.4
1.2
1.0
0

.:;3

e! 0.8
~

~ 0.6

0.4
0.2
0
(n)

non
6d
-preg
(4)
(4)

13d

ZOd

(4)

(4)

non
6d 13d-preg(4)(4) (4)

20d

(4)

non
-preg
(4)

6d

13d

ZOd

(4)

(4)

(4)

non
-preg
(4)

6d

13d

20d

(4)

(4)

(4)

M± S.D.

* p 0.05<

Fig. 2. The 81M ratio of magnesium.

method were used. 3 )The results of other workers l - 3 ) and ours suggestthat Mg is absorbed in different segments of the intestine as compared to Ca, and the absorption via active
transport does not increase during gestation.
In summary, the duodenum is thought to be theprincipal site for Ca absorption, which showed a significant increase in Ca absorption during pregnancy.
The active transport of Mg in the colon may exist ina nonpregnant state, while no such evidence was ob-

144

served during gestation. The present data suggest thateach part of the intestinal loop is responsible for theabsorption of a particular cation.
References
1) D. Schachter et al.: Am. J. Physiol. 196, 357 (1960).
2) K. Takeuchi et al.: Folia Endocrinol. Jpn. 64, 1175
(1988).
3) L. Hardwick et al.: Am. J. Physiol. 256, G720 (1990).

RIKEN Accel. Prog. Rep. 34 (2001)

Influence of Lanthanum on the Uptake of Various
Elements by Marigold
H. Suzuki,*1 H. Kumagai,*1 F. Mori,*2 K. Sakamoto,*2 K. Inubushi,*2 and S. EnomotoMore than 20 elements in the periodic table havebeen detected in plants. C, H, 0, N, P, K, S, Mg, Ca,
Fe, Mn, Zn, Cu, CI, Band Mo are currently considered to be essential for all higher plants. Recently,
a Research group in China reported on the beneficial effects of small applications of rare-earth elements(REEs) such as La and Ce on the growth of crops insoils of low extractable REEs content. I) However, thestudies conducted by Diatloff and Smith 2) showed that
La and Ce was highly toxic to plants. Shinano et al. 3 )reported that plant growth is related to nutrient uptake ability such as that for N. If the influence of
REEs on the uptake of some elements by plants is investigated, it may serve to clarify the role of REEs on
plant growth. In this study, the influence of La on the
uptake of various elements by plants was studied using
the multitracer technique.
Seeds of marigold plants (Tagetes patula L. cv.
Bonanza spray) sowed in 9-cm pots (240 mL in volume)
containing 400 g of river sand applied with (La treatment) or without La(N0 3h of 10 p,mol La kg- I sand.
As the elongation of the root from the marigold seed
was seriously affected at La concentrations higher than
50 p,mol La kg- I sand, the experiment was carried out
at a concentration of 10 p,mol La kg- I sand. Plants
were grown under biotron with a 16/8 hr day/night
regime, 15,000 lux, 65% relative humidity and 25°C.
The marigold seedlings were thinned to 1 plant per pot
seven days after sowing. Throughout the experiment,
the pots were weighed twice a day and watered to 55%
of the water holding capacity (WHC) of river sand.
The details of the plant nutrient management practicewere described in our previous paper. 4)
A multitracer solution was prepared from a Ag target that was irradiated with a 135 MeV/nucleon I4N
beam accelerated by the RIKEN Ring Cyclotron. The

Ag target was dissolved in HN0 3 and then the Ag was
precipitated with HCI as AgCI, leaving another multitracer in solution. The solution was evaporated todryness, and dissolved in fertilizer solution for the experiments. A multitracer containing the radionuclidesof 7Be, 22Na, 46SC, 51Cr, 54Mn, 59Fe, 56Co, 65Zn, 75Se,
83Rb, 85Sr, 88y, 88Z r and 95mTc was applied 29 days
after sowing. The chemical forms of the radionuclides
on administration were assumed to be Be 2 + , N a + ,Sc 3+, Cr 3+, Mn2+, Fe3+, Co 2 +, Zn 2+, Se032- , Rb+,
Sr 2+, y3+, Zr 4+, and Tc04 - .5) The plants were sampled for analysis 21 days after the multitracer addition.
The radioactivities of the plants were measured using
Ge semiconductor detectors. The radioactivity applied
to the pot was taken as 100% and by comparison, theradioactivity of the plant was expressed as a percentage of the uptake (relative uptake, % of DOSE).
Table 1 shows the relative uptake of radionuclides
and the fresh weight by plant. The fresh weight of theaerial parts of marigold was decreased by La application, while the fresh weight of roots was not affectedby La application. The relative uptake of 7Be, 22N a,
51Cr, 59Fe, 56Co, 65Zn, 85Sr , 88y, 88Z r and 95 mTc in
La treatment was similar to that in control. The relative uptake of 46Sc in La treatment was larger thanthat in control, while those of 54Mn, 75S e and 83Rb
in La treatment were statistically lower than that incontrol.
Ishikawa et al. 6 ) reported that La3+ impaired thepermeability of the plasma membrane of the whole cells
in the root-tip portion. Therefore, the uptake of 46Sc,
54Mn, 75Se and 83Rb in La treatment may be affectedby the impairment of the permeability of the plasma
membrane. As the effect of Rb + and K+ on plant absorption is almost the same, the lower uptake of 83Rb
in La treatment reveals the inhibition of K uptake by

Table 1. Fresh weight of plant and relative uptake of various radionuclides by plant. a)Treatment

Control
La treatment

Fresh weight{g 2lanrl}
A. p.b) Root
6.42
3.26
5.60
2.95

'Be
0.1
0.1

22Na
17.1
14.3

46SC
1.6
2.1

SICr
1.2
1.6

S4Mn
19.4
14.5

Student's t -teste)
n.s.
**
n.s.
n.s.
n.s.
*
*
Each value is presented as the mean of data from four plants.
b) Aerial parts: e) n.s., not significant, *P< 0.05; **P< 0.01; ***P< 0.001.

Relative uptake{%ofDOSE}
S9Pe 56CO 6SZn
'SSe
22.4
1.5
9.8
9.3
18.0
1.7
9.9
10.0

83Rb
46.9
18.5

85Sr
6.5
5.9

88y
2.4
2.7

88Zr
1.2
1.3

9S"'Tc
67.2
67.5

n.s.

***

n.s.

n.s.

n.s.

n.s.

n.s.

n.s.

*

a)

*1
*2

Radioisotope Research Center, Chiba University
Faculty of Horticulture, Chiba University145La. An example of interference with K+ transport wasalso presented by Leonard et al. 7) who demonstrated
that the short-term influx of 86Rb as a tracer for K+
into corn root segments was inhibited by La(N0 3 h.
Since K and Mn are essential for plant growth, the red uction of the fresh weight of the aerial parts by La
application is probably related to the inhibition of Mn
and K uptake. However, Se and Sc are not essential
for plant growth. Therefore, further study is required
to elucidate the relationships among the reduction of
the fresh weight of the aerial parts, the increase in 46SC
uptake and the decrease in 75Se uptake by La application.
References
1) P. H. Brown , A. H. Rathjen, R. D. Graham, and D. E.

146

2)
3)

4)

5)
6)
7)

Tribe: in Handbook on the Physics and Chemistry ofRare Earths, edited by K. A. Gschneidner, Jr. and L.
Eyring, (Elsevier Science, Amsterdam, 1990), p. 423.
E . Diatloff and F. W . Smith: J. Plant Nutr. 18, 1963
(1995) .
T. Shinano, M . Osaki, S. Yamada, and T . Tadano: Soil
Sci. Plant Nutr. 40, 485 (1994).
H. Suzuki, H. Kumagai, K. Oohashi, K. Sakamoto, K.
Inubushi, S. Enomoto, and F . Ambe: Soil Sci. P lant
Nutr. 46, 283 (2000).
RIKEN Rev., No. 13 (1996).
S. Ishikawa, T. Wagatsuma, and T. Ikarashi: Soil Sci.
Plant Nutr. 42, 613 (1996) .
R. T. Leonard, G. Nagahashi, and W. W. Thomson:
Plant Physiol. 55, 542 (1975).

RIKEN Accel. Prog. Rep. 34 (2001)

Chemical Isolation and Purification of 95mTc from Distilled Waste
Fraction during Multitracer Separation of Ag Target
T . Tsuji,*1 T. Tarohda,*1 K. Washiyama,*2 R. Amano, and S. Enomoto
Technetium (Tc) is an artificial radioelement with
Z = 43. A long-lived 99Tc (2.14 x 105 y) is ofgreat practical importance in the nuclear fuel cycle,
and its behavior in the environment requires special
consideration. 1) A ,-emitting Tc isotope has beensought for use as a chemical yield tracer for 99Tc
(which has only {3- -rays and no ,-rays), and can beselected from the following candidates: 93Tc (2.75 h) ,95Tc (20 h), 95mTc (61 d), 96Tc (4.28 d), and 99mTc(6 h). Some of these candidates exist in the irradiatedAg target during multitracer preparation. The isotope
95mTc is the most ideal owing to its half-life and its,-ray energies. In this report , we describe the chemical isolation of 95mTc and 96Tc from the Ag target
irradiated by the RIKEN Ring Cyclotron, and the purification of these isotopes to obtain a pure Tc sample
for further instrumental analysis.
Figure 1 shows the flow chart of the process of Tc
isolation and purification from a Ag target. A multitracer was obtained from the irradiated Ag target according to the method of Ambe and coworkers. 2- 4) Few
volatile radioactive species were presented in the multitracer solution to be distilled in the stream of HN0 3
and HCI acid solvent. However, Tc species were transferred with acid distillate into a cooled reservoir. To
isolate the Tc species, the distillate (including Tc) was
diluted 10 times with pure water, and then the diluted

Fig. 1. Flow chart of Tc isolation and purification from
irradiated Ag target.
*1*2

Graduate School of Natural Science and Technology,
Kanazawa University
School of Health Sciences, Faculty of Medicine, Kanazawa
University

Table 1. The observed ,-emitting nuclides and their activities in Tc fraction and multitracer solution.
NuclideHalf-Life r-Ener~ ~keV~ Branchinl % Activi~ ~kB~
Tc distilled fraction
95'"Tc
61d
8.5
582.5
30
96Tc
43.2
4.28d
778.2
99.8
680e
3(68Ga )1077 .4(68 0a)
270.8d
66.4
75Se
0.9
119.78d
264:7
58.5
multitracer solution
7Be
10.5
1128.753.12d477.6
46SC1120.5100
70.9
83.79d
48V
15.97d
983.5
100
8.8
51 Cr
27.7d
320.1
10.1
164.1
59 Fe
44.5d
1099.3
56:5
11.9
54Mn
834.9
100
90
312.3d
56 CO
22.2
100
77.27d846.8
68CO
70.86d
810.8
99.5
242.2
85
Zn
123.9
1115.6244.26d
50.6
74As
17.77d
21.9
595.8
59
75Se
264.7
101
119.78d
58.5
83Rb
86.2d
520.4
45
952.9
B4Rb
32.77d
881.2
69
109.1
85 Sr
64.84d514
1350.9
96
86Zr
83.4d
392.9
97.2
355.4
99 Rh
72
528.2
16.1d
33
lOlmRh
94
170.9
4.34d
306.9

(r-ray measurement was performed on the 20th day after
irradiation)

solution was dried on a hot plate under an infrared
lamp. The residue was dissolved in pure water, andthe resulting solution was poured into an Al 20 3 column to purify the Tc species. The effluent solution
was collected as the purified Tc fraction.
Table 1 shows all of the radionuclides in the Tc fraction and the multitracer solution. The radioactivitiesof 95mTc and 96Tc were 8.5 and 43.2 kBq, respectively.
The chemical species of the isolated Tc in the distilled(HN0 3+HCI) solution were presumably in the formof TeCh, which was volatile and transferred with theacid stream into the reservoir. The Tc chemical species
were changed to nonvolatile TC04 - species by diluting
the Tc acid solution 10 times with pure water. Usingan Ab03 column, the impurities 68 Ge and 75Se wereabsorbed on Al 20 3 and removed from the Tc fraction.
The final 95mTc and 96Tc fraction was confirmed to bevery high in radionuclidic purity.
References
1)
2)
3)
4)

K. H. Lieser: Radiochim. Acta 63, 5 (1993).
S. Ambe et al.: Chern. Lett . 1991, 149.
S. Ambe et al.: Anal. Sci. 7, Suppl., 317 (1991).
S. Ambe et al.: J. Radioanal. Nucl. Chern. 195, 297(1995).

147

RIKEN Accel. Prog. Rep. 34 (2001)

Synthesis of Chemical Separator for Metals Produced by
the Multitracer Method
Y. Komatsu,* H. Yamada,* M. Sekita,* and S. Enomoto
As multitracer solution has up to 50 elements, a separation technique is very important to separate effective elements for use in medical and biological fields.
The layered dihydrogen tetratitanate, H 2Ti 4 0 g 'nH 2 0,
fibres were a useful chemical separator for picking up
effective ions in the solution.
The H 2Ti 4 0 g • nH 2 0 fibres were synthesized frompotassium tetratitanate, K 2Ti 4 0 g , fibres by the flux
method.
This involved passing hydrochloric acid
(1 mol dm- 3 ) through a column to convert H 2Ti 4 0 g
into layered dihydrogen tetratitanate hydrate fibres.
An aqueous standard solution of cobalt(II) ions was
prepared by dissolving cobalt(II) chloride in water.
The distribution coefficient, Kd, was calculated aswhere C1 is the amount of adsorbed cobalt(II) ions per
1 g of the solid and C2 is the concentration of cobalt (II)ions per 1 cm 3 of the aqueous solution.
Figure 1 shows the dependence of the logarithm of
the distribution coefficient, K d , of the layered dihydrogen tetratitanate hydrate fibres on the pH in the
aqueous phase for ten different temperatures between
25 and 250°C. In these experiments, the concentrationof hydrogen ions in the solid phase was kept constantduring the adsorption of cobalt(II) ions. The slopes ofthe lines for 25°C and 100°C are approximately 2.0.
The reaction for the adsorption of cobalt(II) ions to
the fibres under these conditions can be expressed by
the ion exchange reaction:
mCo + (aq) + H 2 Ti 4 0 g • nH 2 0(s)2----+ 2mH+ (aq)+ Co m H 2 (1-m) Ti 4 0 g . nH 2 0(s),where the subscripts "aq" and "s" denote the aqueousand solid phases, respectively, and 0 < m < 1. The
slopes of the lines for 125 and 250°C are lower than
+2.0, namely, approximately +l.6 at 125- 150°C andapproximately + l.0 at 175- 250°C, respectively.
By plotting pHl/2' which is defined as the pH value
in the aqueous solution when 50% metal ions was ion
exchanged on the fibres, vs. reaction temperatures, thepHl/2 values decrease with an increase in the temperature from 25 to 100°C, whereas the values increase
with an increase in the temperature from 100 to 250°C.
The layered dihydrogen tetratitanate hydrate fibres described above adsorb cobalt(II) ions in aqueous solutions at the temperatures used. This shows that theadsorption of cobalt(II) ions to the fibres is controlled
by the original structure of the solids.
National Institute for Research in Inorganic Materials

148

4~--~~--~-r-----r---c~.. • a.'=." .0.

3~

..

,-

u

0> 2-

.Q

,- 0' . .

: i~.~··cj"·:, ·e;:,• .0.

100 75
50

/>

o

3

pH

4 2

3

pH

Fig. 1. Distribution coefficient, Kd, of cobalt(II) ions as afunction of pH in the aqueous phase at various temperatures.

2S'C

£

(IJ
~

::J

CE

so·e
7S·C
100·C
o
12S C

~

(IJ

Q.

E 17S·C:.--_ _ _-'" ..._ _ ....._~ 200·C ~---.I. '---.I"."'--.--i'_1~:_ J ......

225°C~---.I,,'---"':----''_i

250·C L.1...•...----""'O""'.--.I..J.---=3"="O.;---...NJ,..4":"':O:a.--~Z0

28 (degree, CuKa)
Fig. 2. X-ray powder diffraction patterns of the solid samples treated with aqueous solutions at ten different temperatures.

The dihydrogen tetratitanate hydrate fibres havea layered structure similar to that of potassium
tetratitanate. 1 ) Figure 2 shows the X-ray powder
diffraction patterns of the layered dihydrogen tetratitanate hydrate fibres treated with aqueous solution
at ten different temperatures between 25 and 250°C.
The fibres treated below 100°C show almost the same
patterns as the original fibres. This finding indicatesthat the structure remains virtually unchanged up to
125°C. The solid samples treated at 125-200°C turned
powdery, which can be clearly seen in the change ofthe diffraction patterns as shown in Fig. 2, particularly above 150°C. Based on a detailed analysis of thediffraction patterns, the fibrous structure is changed
to anatase and/or these intermediate phases above
125°C which give three peaks in the diffraction pat-terns. This anatase and/or these intermediate phases
are also known to have the capability of adsorbing
cobalt(II) ions.
In conclusion, dihydrogen tetratitanate hydrate wassynthesized to be capable of adsorbing Co(II) ions from25 to 250°C. This was applicable to other metal ionswhen the reaction temperature was 25°C,1) thus thedihydrogen tetratitanate hydrate can be used as thechemical separator for metals produced by the multitracer method.
References
1) T. Sasaki et al.: Sep. Sci. Technol. 18, 49 (1983).

149

RIKEN Accel. Prog. Rep. 34 (2001)

Ion Exchange Separation of Divalent Metal Ions from Iron (III)through 2,2'-Bipyridyl Complex Formation
Y. Gorai,*1 Y. Komatsu,*2 S. Enomoto, and K. Oguma*1
The improvement in the selectivity of ion exchange
resin to metal ions by complex formation reactions
is important and interesting from the standpoint ofmetal separations as well as the solution chemistry ofmetal ions. The addition of an organic base to a solution of metal ions, which forms stable complexes withthe base added, might prevent the ion exchange adsorption of the metal ions to give lower distribution
coefficients (Kd) . However, metal ions which do notform complexes with the base added could still givethe same distribution coefficients even in the presenceof the base. The present study was undertaken to improve the selectivity of iminodiacetate-type chelating
resin, Diaion CR 11 (Mitsubishi Chemical Co. , Tokyo),to transition-metal ions by the addition of pyridine or
2,2'-bipyridine. These reagents were employed because
they are well known to react with various transitionmetal ions to form relatively stable complexes. Copper(II) , nickel (II), and cobalt (II) in the presence of 2,2'bipyridine were found to exhibit lower Kd values thanthose in the absence of 2,2'-bipyridine because of 2,2'bipyridyl complex formation. Iron (III) gave the same
distribution coefficients regardless of the addition of
2,2 '-bipyridine.
Distribution coefficients (Kd) were measured by abatch method at 25°C. A buffer solution containing
appropriate amounts of transition-metal ions and Diaion CR 11 in an Erlenmeyer flask was shaken for 24 hand the transition-metal ion in the solution phase wasdetermined by atomic absorption spectrometry or inductively coupled plasma atomic emission spectrometry. The Kd values were calculated using the following equation: Kd = amount of metal on resin (g/g)1
amount of metal in solution (g/ml). The Kd values
for transition-metal ions in the media containing pyridine or 2,2'-bipyridine were also calculated in the samemanner.
The Kd values for copper (II) , nickel (II) , cobalt (II) ,and iron (III) obtained in buffer solutions (without anorganic base) are shown in Fig. 1 (A). The selectivity of
Diaion CR 11 to transition-metal ions increased withincreasing the stability constants of the metal complex
with iminodiacetic acid. 1) The selectivity decreased in
the following order: Fe (III) > Cu (II) > Ni (II) >Co (II). The addition of pyridine to the buffer solution did not affect the Kd values of the transitionmetal ions tested. This is because pyridine reacts withthe transition-metal ions to form complexes of low*1*2

150

Department of Materials Technology, Faculty of Engineering, Chiba University
National Institute for Research in Inorganic Materials

(8)

3

,

I

-

J

o~--~--~--~--~---opH

Fig. 1. Distribution coefficients for transition-metal ions on
Diaion CR 11 in the absence (A) and presence (B) of
2,2'-bipyridine (10- 2 M) . • Fe(III), • Cu(II), ... Ni(II),... Co(II).

stability constants. On the other hand, the presence of
2,2'-bipyridine (10- 2 M) shifted the adsorption curvesof copper (II), nickel (II), and cobalt (II) to the higher
pH region (see Fig. 1 (B)). These transition-metal ions
are known to form stable 2,2'-bipyridyl complexes 1)
and their adsorption on Diaion CR 11 might be prevented by the presence of 2,2'-bipyridine. Iron (III)does not form stable complexes with 2,2'-bipyridine
and its Kd value was not affected by the addition of
2,2 '-bipyridine to the buffer solutions.
The selectivity of Diaion CR 11 towards iron (III)was improved by the addition of 2,2'-bipyridine to thebuffer solution as described above. Therefore, the separation of iron (III) from copper (II) , nickel (II) or
cobalt (II) was attempted using CR 11 in combination
with the buffer solution (pH 1.3) containing 10- 2 M
2,2'-bipyridine. A sample solution containing iron (III)and copper (II) (or nickel (II)) was loaded on a Diaion CR 11 column to retain iron (III) on the column.
Copper (II) (or nickel (II)) passed through the column
and was determined by atomic absorption spectrometry. Iron (III) adsorbed on the column was quantitatively recovered by elution with 1 M hydrochloric acid.
Cobalt (II) reduced iron (III) to iron (II) in the presence of 2,2'-bipyridine, and iron (II) passed throughthe Diaion CR 11 column as a 2,2'-bipyridyl complex
as did copper (II) and nickel (II). Accordingly, it was
impossible to separate iron (III) from cobalt (II).
References
1) L. G . Sillen and A. E. Martell: Stability Constantsof Metal-Ion Complexes (Chemical Society, London,
1971).

RIKEN Accel. Prog. Rep. 34 (2001)

Ion-Size-Selective Masking Effect in Metal Ion Separation
S. Umetani,*1 S. Tsurubou,*2 Y. Komatsu,*3 and S. Enomoto
Application of a masking effect to the solvent extraction method is an effective means for selective separation of metal ions. In the solvent extraction ofalkali , alkaline-earth and lanthanide metal ions using
chelating reagents, metal ions with small ionic radii
exhibit high extractability. On the other hand, thestability of complex formation between macro cyclic
ionophores and the above-mentioned metal ions exhibits a different tendency. A solvent extraction system of high selectivity could possibly be developedby the combination of chelating reagents and macrocyclic ionophores. 18-Crown-6 and crypt and [2.2.2]
have been shown to be useful ion-size-selective masking
reagents in the synergistic extraction of alkaline earths
into cyclohexane using I-phenyl-3-methyl-4-benzoyl-5pyrazolone (HPMBP) and tri-n-octylphosphine oxide(TOPO).1- 4) In the present study, a novel macro cycle
application is proposed.
Extraction of alkaline earth metals in thepresence of I8-crown-6. Alkaline earth metals wereextracted into cyclohexane using 0.05 M HPMBP and
0.01 M TOPO in the order Mg > Ca > Sr > Ba,
which is the order of decreasing ionic radius. I ,2) When
0.03 M 18-crown-6 was added to the aqueous phase,the extractions were carried out in the high pH region.
The larger the ionic radius, the higher the pH region
the extraction moved to. As a result, the separation
among alkaline earth metals, particularly for Ca/Srand Sr/Ba, has been improved. It is clear that 18crown-6 works as an ion-size-selective masking reagent
in the aqueous phase.
In the synergistic extraction of alkaline earths (M 2+)
using HPMBP (HA) and TOPO (L), the extraction
equilibrium and the extraction constant, Kex,s, can be
written as follows:

distribution ratios.
SF = log (DMI/DM2 = log(K ex ,s,Ml/K ex ,s,M2)(4)

The separation factor in the presence of crown ether,SF* {(defined as log(D 111 /D M2 )}, is expressed as
Eq. (5) when sl and s2 are the same and [CE] is sufficiently high.
SF* = log (K ex ,s,MI/K ex ,s,M2)(,BM2/,BMI)(5)

Comparing Eqs. (5) and (6), the separation factor canbe improved by as much as ,BM2/ ,BMI. Separation factors in the presence and absence of crown ether are
shown in Ref. 2.
Extraction of alkaline earth metals in thepresence of cryptand [2.2.2]. Diazapolyoxabicyclic
ligands (cryptands) exhibit a prominent selectivity foralkali and alkaline earth metals. They are soluble inwater and their stability in complex formation is sufficiently high for use as a practical masking reagent.
Incorporating nitrogen as an element constituting thering structure, the masking effect of cryptands depends
on pH, unlike in the case of crown ethers such as 18crown-6. 3,4) The extraction using 0.01 M HPMBP and
0.01 M TOPO into cyclohexane in the absence andpresence of 0.01 M cryptand [2.2.2] has been examined.
The extraction behaviors for Mg and Ca in the presence of crypt and [2.2.2] are quite similar to those in
the absence of crypt and [2.2.2]. The log D values for
Sr in the presence of crypt and [2.2.2] begin to decrease
above pH 5. The log D values for Ba in the presenceof crypt and [2.2.2] deviate from those in the absenceof cryptand [2.2.2] above pH 4.5.
In order to establish the quantitative extractionseparation system for Ca and Sr, the extraction was
carried out at reduced HPMBP and TOPO concentrations of 4 x 10- 3 M, keeping the initial concentrationof crypt and at 0.01 M. The distribution ratio of Sr deM 2+ + 2HAo + sLo = MA 2Ls,o + 2H+(1)
creases rapidly above pH 5.6 as expected, while that of(2)
Kex,s = D[H+]2 /[HA]~[L]~,Ca still increases by pH 7.5. Calcium can be separated
from Sr quantitatively in the pH range of 7.2 to 8.6
where the subscript 0 denotes the species in the organic
where more than 99% Ca (log D > 2) is extracted into
phase and D is defined as [MA2Ls]0/[M2+].
cyclohexane, while more than 99% Sr (log D < -2) reThe distribution ratio in the presence of 18-crown-6
mains in the aqueous phase at the same time. Careful(CE) , D* , can be expressed by Eq. (3).
. control of pH at 7.8 could lead to the most optimum
D* = [MA2Ls]0/{[M2+] + [M(CE)2+]}
separation: 99.9% extraction of Ca (log D > 3) with
99.9% of Sr (log D < -3) remaining in the aqueous= Kex,s [HA]~[L]~/[H+]2{1 + ,B[CE]}(3)phase. 3)
The separation factor in the absence of crown ether,
SF between two metal ions, M1 and M2, is defined as
References
1) S. Urnetani, M. Matsui, and S. Tsurubou: J. Chern.
th~ difference in the logarithmic value of the respective
*1

*2
*3

Institute for Chemical Research, Kyoto University
Department of Chemistry, Asahi University
National Institute for Research in Inorganic Materials

Soc., Chern. Commun. 1993, 914.
2) S. Tsurubou, M. Mizutani, Y. Kadota, T. Yamamoto,
S. Umetani, T. Sasaki, Q. T . H. Le, and M. Matsui:
Anal. Chern. 67, 1465 (1995).

1513) T. Sasaki, S. Umetani, M. Matsui, and S. Tsurubou:
Chern. Lett. 1994, 1195.

1524) S. Tsurubou, S. Umetani, and Y. Komatsu:
Chim. Acta 394, 317 (1999).

Anal.

RIKEN Accel. Prog. Rep. 34 (2001)

Multitracer Study on the Diffusion of Various Ionsin the Porewater of Granite
C. Egawa,* Y. Takahashi,* S. Enomoto, R . Hirunuma, and H. Shimizu*
The presence of various elements in micropores ofrocks introduced by diffusion of groundwater should bequantified from various environmental aspects. After
high-level radioaotive waste is disposed of in a deep
underground repository, it is possible that some radionuclides are leached from the waste and transported
through the surrounding rocks by groundwater.1) The
diffusion also influences dispersal of toxic metals entering the environment as a result of more general humanactivity such as industrial installation. For evaluating the transport of these elements in the geosphere,
it is important to understand the diffusion behavior of
the elements introduced in to rocks by groundwater.
In this study, diffusion experiments were conductedusing a multitracer containing 14 radioisotopes eBe,
48V, 51 Cr, 54Mn, 58CO, 59Fe, 65z n , 74 As, 75Se, 83Rb,
85S r , 88y , 88 Zr , and l03Ru) to discuss the relationshipbetween differences in the chemical characteristics ofthese elements and their diffusion behavior.
The apparent effective diffusivity (De) was determined by the through-diffusion method. 2 ) Granite
samples from drilling cores of the Toki granitic rocks(from central Japan) were cut into 5-mm-thick and
30-mm-diameter disks. Each disk was fitted tightly
between . two cells (volume: 100 cm 3) filled with water (pH 4, NaCI 0.10 M). The multitracer solution pre14-e- Rbfor both fresh and weathered granites. This result is
worthy of note, since the diffusions of various elementsin the porewater of granite can be approximately formulated using Dv by such a simple relation. From autoradiography analysis, diffusion pathways were foundin grain boundaries and cleavages of biotites and pla--e- Rba. Weathered granite

--.-

12

-+- Sr--.-- Mn

10----------+- SrCo
-H3- Zn-e--.- y~------ Se

10---tr-

6' 8
~

(1)

De = cDv

14

12

3

pared from a Ag target was injected into one cell. Radioactivities of the nuclides transported into the othercell were determined using a Ge detector after various
time intervals.
Diffusion curves were obtained for two granite samples: a fresh one and a weathered one (Fig. 1). Amongthe 14 elements studied, the diffusions of Be, Mn, Co,
Zn , Se, Rb , Sr, and Y were observed for the weathered granite sample (Fig. 1 (a)). For the fresh granite
sample, only the diffusions of Mn, Se, Rb, and Sr wereobserved (Fig. 1 (b)). The difference may be due tothe larger porosity (c) of the weathered granite (1.0%)
than of the fresh one (0.42%). The diffusion curve wasfitted by Fick's equation to obtain De values. The Defor each element was plotted against the bulk diffusivity in aqueous solution (Dv), as shown in Fig. 2. The
De values for Rb , Sr, Zn, Co, and Mn were plottedclose to a line indicated byBe

h. Fresh granite--.-- Mn
Se

8

6

6

4

4

2

2

0
0

20

40
60
Time (day)

80

20

40
60
Time (day)80

Fig. 1. Diffusion curves through a 5-mm-thick granite disk for (a) weathered and (b) fresh granite. The
y axis shows the concentration ratio of each element in the diffusion cell to the initial concentrationin the tracer cell.
Department of Earth and Planetary Systems Science, Graduate School of Science, Hiroshima University

153De '" f•Dv~;;~re_8h__)____~
Weathered Fresh

Rb .
Sr.
Mn A
Co
"
Zn -

lSI

o

10.9

Be

113

y

lSI

Se

0

0
0

10.8

Diffusivity in water, Dv (m2/s)

Fig. 2. Relationship between effective diffusion coefficients(De) and diffusion coefficients at infinite dilution inaqueous solution (Dv) for various ions in weathered andfresh granite.

gioclases in the granite. This is consistent with thefinding that the diffusion was mainly controlled by theporosity. Biotite separated from the granite using amagnetic separator was employed for batch sorption
experiments. The amounts of sorbed Be and Y werelarger than those of Rb, Sr, Zn, Co, and Mn . Thisimplies that Be and Y were not diffused through porewater, but through the Donnan phase in the vicinity ofthe mineral surfaces. This mode of diffusion is referred
to as "surface diffusion" .3)154

No diffusion of V, Cr, Fe, As, Zr, or Ru was observed. This can be attributed to two factors: (1) theslow diffusion rate of the elements and (2) the strong
affinity of the elements on the mineral surface. From
batch experiments, the sorbed fraction of As was lessthan those of Be and Y which were transported into
the other cell. This finding eliminates the second factor
as the cause of the lack of diffusion of As. Hence, it is
implied that the diffusion rate of As is slow comparedwith those of other ions such as Be and Y . Under our
experimental conditions, As forms oxyanions such as
As(III)033- or As(V)O 43- . The present results suggest that the diffusions of the oxyanions are slower inthe porewater than those of other cations having similar Dv to these anions. This seems also valid for explaining the slower De of Se, which forms Se032- orSe042- , than those calculated using Eq. (1). For Cr,
Fe, and Zr, the batch experiments showed that mostof them were sorbed on the biotite surfaces, indicatingthat the reason the diffusions of these ions were notobserved was because of the second factor (i. e., strong
affinity for the mineral surface).
References
1) D . G . Brookins: Geochemical Aspects of Radioactive
Waste Disposal (SpringIer-Verlag, New York, 1984).
2) T. Yamaguchi and S. Nakayama: J. Contam. Hydrol.
35, 55 (1998).
3) T . Cole, G. Bidoglio, M. Soupioni, M. O'Gorman, and
N. Gibson: Geochim. Cosmochim. Acta 64,385 (2000).

RIKEN Accel. Prog. Rep. 34 (2001)

Development of New Multitracer with Neutron Fission of 235U
A. Shinohara, S. Shibata, K. Takamiya,* and S. Enomoto
The Division of Radioisotope Technology is preparing multitracer solutions with heavy-ion reactions using the RIKEN Ring Cyclotron (RRC) , and providingthem to scientists in the various research fields, suchas, pharmaceutical, biological and environmental sciences. A multitracer is a tracer solution containing
multiple radioactive isotopes without carrier materials.
The preparation method was developed by Ambe andcoworkers l - 3) at RIKEN approximately ten years ago.
However, the available elements are limited by theirown half-lives and reaction yields. Therefore, anothermethod of preparing multitracers containing radioactive isotopes, which cannot be produced by heavy-ion
reactions, is urgently required. We attempted to prepare a multitracer by the thermal neutron-induced fission of 235U because in nuclear fission, neutron-richisotopes are produced in relatively high amounts incomparison with charged-particle-induced reaction. In
this paper, we report on the preparation of a multitracer by the thermal neutron-induced fission of 235U
at Kyoto University Reactor (KUR). 4)
A mixture of natU0 2 and catcher material, in which
the fission products recoiled out from the U0 2 were
captured, was irradiated by thermal neutrons in KUR.
In order to prepare the multitracer solution efficiently,
the following parameters for the sample preparation
were investigated: (1) catcher material, (2) mixing ratio of U0 2 to catcher material, (3) particle size of thecatcher material, and (4) sample shape for irradiation.
The samples prepared were irradiated using the pneumatic transferring system (Pn- 2) at KUR. The content of the samples and the irradiation times ·are tabulated in Table 1. The fission products captured by thecatcher material dissolved in 0.1 N HCI, while the U02
did not. The solution containing fission products was
filtered with suction to separate U0 2. Gamma raysfrom an aliquot of the solution and the U0 2 on the filter paper were measured using a Ge detector to obtainthe yields of the products. The capturing efficiency
of fission products by catcher materials was evaluatedwith the ratio of the yield for each product nuclide
captured in catcher materials to the total yield.
Figure 1 shows the mean capturing efficiency foreach sample as a function of the weights ratio of
Wcatcher /Wtotal, where Wcatcher and Wtotal are theweight of the catcher material and the sample, respectively. The sample mixed with NaCl as a catcher material is efficient for preparing multitracer solutions.
The multitracer solutions prepared above were extensively used for biological research to trace the element distribution in mice. In this research, the mulResearch Reactor Institute , Kyoto University

Table 1. Contents of irradiated samples.

Catcher
Material

Weight /mg

Form

U02 :Catcher

Powder(coarse)NaCIPowder(fine)

PelletMgCl 2
LiF

Powder (fine)Powder (fine)

0.95:2.95
1.12:9.68
1.06:29.74
1.09:1.11
1.07:3.33
1.05:29.45
5.12:5.18
2.48:7.72
1.25:10.85
0.37:10.43
1.00:29.61
0.90:9.60

Irrad. Time
10min
1min
1min
5min
5min
1min
2min
2min
5min
2min
5min
5min

>,0.9

u

!:=

(1)

·u
i.E 0.8
r.:a
00
!:=

·cO.7
='

~

U O.6

0.5 '---L...-.....JL.......J-----L-----L---'---'----'-----'-----'----'-----'
0.4 0.5 0.6 0.7 0.8 0.9
1
WCatchel "Wfotal

Fig. 1. The mean capturing efficiency for each sample correlated with the weight ratio W cat cher /Wtot al. Open andclosed circles indicate the efficiencies obtained for coarse
and fine powder samples with NaCI as the catcher material , respectively. Square and diamond are those with
LiF and MgCb, respectively. The efficiencies obtainedfor pellet samples with NaCI are also indicated as triangles. Solid and dashed lines indicate the results of theleast-squares fitting for the mean efficiencies of powder
and pellet samples with NaCI , respectively.

titracer solutions obtained from the sample containing N aCl are particularly suitable, because this physiological salt solution can easily be prepared. Besides biological research , applications to environmental, pharmaceutical and cytological sciences are now
being planned.
We are also planning to prepare a new multitracer

155

containing short-lived isotopes with KUR or RRC.
A new target system containing both the target andcatcher materials and a rapid on-line chemical apparatus will be designed for this purpose.
References
1) S. Ambe, S. Y. Chen, Y. Ohkubo, Y. Kobayashi, M.
Iwamoto, M. Yanokura, and F. Ambe: Chern. Lett.

156

1991 , 149.
2) F. Ambe: RIKEN Rev ., No.4, 31 (1994).
3) S. Ambe, S. Y. Chen, Y. Ohkubo, Y. Kobayashi, H.
Maeda, M. Iwamoto, M. Yanokura, N. Takematsu, and
F. Ambe: J. Radioanal. Nucl. Chern. 195 , 297 (1995).
4) K. Takamiya, M. Akamine, S. Shibata, A. Toyoshima,
Y. Kasamatsu, and A. Shinohara: J. Nucl. Radiochem.
Sci. 1, 81 (2000).

RIKEN Accel. Prog. Rep. 34 (2001)

Compton Camera for Multitracer
Y. Yang,* S. Motomura,* Y. Gono, * S. Enomoto, Y. Yano , and K. Asahi
In the multitracer technology, many radioisotopes
are used simultaneously. Therefore, for a detection
system to identify the positions of many tracers, itis necessary to measure the gamma ray energy spectrum with a high energy resolution. Although Compton cameras for single photon imaging consisting of asegmented Ge detector and scintillitors have been proposed for years,l) it is necessary to use two segmented
Ge detectors for multitracer technology. The advantages of a Compton camera over a conventional mechanically collimated gamma camera are a wide fieldof view, high efficiency, and high image resolution athigh gamma ray energy.
Monte-Carlo simulations were performed with the
GEANT program to determine the efficiency and resolution of the proposed Compton camera as well as
to optimize its detector system. The dependence ofthe efficiency on gamma ray energy and the distributions of the number of scattering of gamma raysin two segmented Ge detectors were also simulated.2)
The following conclusions were reached. The optimum
thicknesses of the first detector and the second detector
were 1 cm and from 2 cm to 4 cm, respectively. The optimum distance between the two detectors was about
8 cm in the case when the distance between the source
and the first detector was 6 cm. Large areas for thetwo detectors were preferred. The optimum ratio of
the area of the first detector to that of the second detector was about 2/3. A Compton camera can operate
for a wide energy range of gamma rays. In a Compton camera, only when gamma rays undergo Compton
scattering in the first detector and then the scatteredgamma rays are fully absorbed in the second detector can these events be used for image reconstruction.
These events are defined as good events. The probability of multiple scattering of 1.332 Me V gamma rays
in a 2 cm-thick Ge first detector is about 50 percent forgood events. If multiple scattering occurs in more than
one segment of the first detector, more than one segment give signals, thus the event can be removed fromthe coincident events and will not contribute to thebackground of the image. If multiple scattering occurs
within one segment of the first detector, the event cannot be distinguished from single scattering events andwill contribute to the background of the image. The
probability of multiple scattering of 1.332 MeV gamma
rays in a 2 em-thick Ge second detector is about 90
percent for good events. The average multiplicity is
3. The multiple scattering events occurring within one
segment can be directly used for image reconstruction.
If multiple scattering occurs in more than one segment,
Department of Physics, Kyushu University

10 ~---------------------,

5000

4000

_4
E

.3.2
c::

3000

'iii
~ ·2

2000

,g 0
>. ·4

·6

1000

·8
-10_ 10 -8

-6

-4

-2

0

2

4

6

8

10 0

x Position (em)Fig. 1. Two dimensional-image of three sources.

the event can be removed from the total coincident
events, which lowers the efficiency. If a tracking algorithm is used to identify the interaction order, some ofthose events may be tracked and used for image reconstruction.
A test experiment was performed using a Compton
camera consisting of two existing segmented Ge detectors. Each detector is a planar-type Ge detector of
50 x 50 x 20 mm 3 segmented by an electrode into 25
segments of an equal size of 10 x 10 x 20 mm3 . Two
detectors were placed in parallel and the distance between their centers was 6 cm. Three sources of 60Co,
137 Cs, and 152Eu were placed in a plane perpendicular
to the center axis of the Compton camera. The distance from the source plane to the center of the firstdetector was also 6 cm. Only seven segments of thefirst detector and nine segments of the second detector
were used in the experiment due to the availability ofthe electronic modules. By setting energy windows on
the peaks of three sources in the measured gamma rayenergy spectrum, two-dimensional images can be obtained. Figure 1 shows the identified positions of threesources. It is seen that the present system functions ina manner suitable for multitracer technology.
As the next step, we plan to develop a Compton
camera consisting of two strip Ge detectors. A muchbetter image resolution is expected through the use ofthis Compton camera. The cost of electronics can also
be greatly reduced compared with a Compton camera
consisting of two segmented Ge detectors if the segment size is the same as the strip width.
References
1) M. Singh and R. R. Brechner: J. Nucl. Med. 31 , 178(1990), and references therein .
2) Y. F. Yang, Y. Gono, S. Motomura, S. Enomoto, andY. Yano: accepted for publication IEEE Trans. Nucl.
Sci. (2001).

157

RIKEN Accel. Prog. Rep. 34 (2001)

Separation of 18F from [18 0] Water by Electrochemical Method
F . Saito, Y. Nagashima,*l T. Kurihara,*2 N. Suzuki, J. Kim, L. Wei, Y. Itoh, A. Goto, and T. Hyodo*l
18F produced from H 218 0 water irradiated by a proton beam from a cyclotron is widely used in the synthesis of radiopharmaceuticals for PET (positron emission
tomography). The 18F is usually separated from theH 218 0 water before synthesis in order to enable to theuse of the H 218 0 water repeatedly. In this process,the efficiency of the recovery of the 18F as well as theefficiency of the synthesis of radiopharmaceuticals isessential. Currently, ion-exchange resins or fibers areused. Although they are efficient, the preparation of
the ion-exchange resins is complex, and residual organic solvent decreases the efficiency of the synthesisof the 18F-Iabelled chemicals. As a result , the H 218 0
water is able to be reused only a few times.
We investigated an electrochemical method which
was developed for producing a 18F spot source of slow
positron beams from H 218 0 water to separate the18F from the H 218 0 water. 1,2) The 18F in the solution was electrodeposited on a graphite rod and thenemitted into the ultrapure water in a different cell(Fig. 1 (a)). The PC controlled electrodeposition apparatus (Fig. 1 (b)) has been reported elsewhere.
The 18F of the activities 150- 227 mCi (5.558.40 GBq) was electrodeposited on a io mm ¢ graphite
rod with electrodeposition voltage of 200 V, and thenemitted into the ultrapure water with an electroemission voltage of 250 V. The efficiency of the electrodeposition for 5 min and the fraction of 18F emitted into theultrapure water for 5 min were 97% and 89%, respec( a)

Anode

I

200V~/f 'SF
ISF Solution (H2 I SO)
l.8ml

\f,J,
Cathode250V

Emission Cell
(Anode)Pure Water
2ml

(b)

~~
Anode

6r~

Fig. 1. (a) Diagram of a graphite rod and a platinum
cell for electrodeposition and electroemission . (b) PCcontrolled electrodeposition apparatus.
*1

*2

158

Department of Basic Sciences, Graduate School of Arts andScience, University of Tokyo
Institute of Materials Structure Science (IMSS), High Energy Accelerator Research Organization (KEK)

0.5
I
Ene rgy (MeV]

Fig. 2. The energy spectra of , -rays from the impurity
metal RI ions in (a) the residual H 2 18 0 water, (b) thegraphite rod, and (c) the recovered 18F solution, normalized to the measurement time.

tively. Thus, as much as 86% of the 18F in the H 218 0
water is available for the synthesis of radiopharmaceuticals for PET.
The (3+ emitted from the 18F ionized the H 20
molecules and produced many charge carriers, as a result, the electric conductivity of the 18F solution became higher. Therefore, no charge carrier of 19F was
added either to the H 218 0 target for the electrodeposition or to the pure water for the electro emission.
The recovered H 218 0 water without carrier impurity ismuch more easily reused than that containing carrier
impurity.
The presence of metal ions in the 18F solution
affects the yields of the synthesis of [18 FJ radiopharmaceuticals. Figure 2 shows the , -ray emission
spectra from (a) the residual H 2180 water, (b) thegraphite rod and (c) the recovered 18F solution. The
peaks of the impurity metal ions such as 52Mn, 56Co,
57 Co and 58Co in the spectrum of the recovered 18F
solution are low, because most of the ions remain in
the residual H 218 0 water. These metal ions were prod uced by the bombardment of protons on the Harvar
foil used for the target holder and recoiled into the
H 218 0 water. Therefore, the metal ions dissolved in
the target H 2180 water must be efficiently removed
from the recovered 18F solution.
In conclusion, this method is promising for routine applications where numerous high-purity fluorides
must be produced.
References
1) F. Saito, Y. Nagashima, T. Kurihara, 1. Fujiwara, R.
Iwata, N. Suzuki, Y. Itoh, A. Goto, and T. Hyodo: Nucl.
Instrum. Methods Phys. Res. A 450 , 491 (2000).
2) F. Saito, N. Suzuki, Y. Itoh, A. Goto, 1. Fujiwara, T.
Kurihara, R. Iwata, Y . Nagashima, and T. Hyodo: Rad .
Phys. Chern. 52 , 755 (2000).

4 . .Radiation Chemistry and Radiation Biology

RIKEN Accel. Prog. Rep. 34 (2001)

Dynamics of Incipient Ion Tracks in Wide-Band-Gap Materials:
Electron-Hole Plasma Luminescence from Ion Tracks andInitiation of Defect Formation
K. Kimura, S. Sharma, and A. PopovWe found novel ultra-fast luminescence decay component (UFLDC) from the track core in a numberof wide-band-gap materials, by measuring fast luminescence decay and time-resolved spectrum (TRS).1)
Samples used were NaF, LiF , NaCI, KCI, CsCI, KBr,
KI, RbI, CsI, BaF2 , MgO, and a-alumina. Thus, the
UFLDC appears to be a common phenomenon in wideband-gap materials except for some kinds of materials such as diamonds and Si0 2. An example, Fig. 1,
is an equi-height plot of wavelength-dependent decay
curves of an RbI single crystal irradiated with Xe-ions
at 6 K. One may recognize the UFLDC in both sidesof slower decays at 320 nm due to the a-self-trapped
exciton (STE); a-band is known to have the lifetime of
3 ns. TRS's were able to be obtained based on Fig. 1 replotted with photons/ion. Consequently, the UFLDC
was characterized by the lifetime of 30 ps (by deconvolution) , the peak at 4 eV, and the width, 1.5 eV, which
are quite different from the known bands.
The UFLDC was largely affected by excitation density (ED). Figure 2 shows the specific intensity of the
UFLDC as a function of ED's due to 2.0 MeV/nucleon
He- , N-, Ar-, Kr- , and Xe-ions. At this energy, theion track is dominantly comprised of the core part.
Equal ion velocities give nearly equal track radii forthe above five ions. Consequently, we can estimate
relative ED without the value of the radius. Now,
the UFLDC increases largely with increasing ED andmoreover its rate is super-linear. This indicates that
the UFLDC originates from the multiple interactions
among the excited precursors. Considering non-tailingdecay curves and their temperature-insensitivity, theprecursors must be short-lived similarly to the UFLDC
and hence they are limited to electron-hole pairs (e-hpairs) or free excitons. The e-h pairs can be formed
so densely here as to exist adj acently since ED for a
Xe ion attains 200- 600eV /atom. Adjacent e-h pairs
can combine immediately, as are adjacent H atoms , toform electron-hole plasmas. Such bindings give rise
to gigantic oscillator strength. 2) The UFLDC may beascribed to e-h plasma luminescence.
The large shift of the UFLDC from the band gap,
quite different from the e-h plasma in semiconductors,
is interesting and may be caused by the ion track. Electrons ejected by an ion expand toward radial directionof the ion trajectory, lose the energy, and return backto the holes, which takes 10- 14 - 10- 13 s. During thisperiod, the dense positive ions and atoms not only lose
the binding for the crystal but also they are put under

2

3

TIME (as)Fig. 1. Wavelength dependent equi-height decay curves of
RbI under irradiation with Xe-ions at 6 K .

10-1:e 10-

2

~

ci.

en

. ·1<01---

10-3
10-4
10
relative ED

100

Fig. 2. Excitation-density (ED) dependence of specific intensity of the UFLDC.

huge Coulomb repulsive force, resulting in deformationof crystal and likely bindings among halogen atoms andanions. Thus, the configuration under recombination
luminescence of the e-h plasma is deformed and rearranged. They all reduce photon energy like Stokes
shift. Simultaneously, this means that the so-called
amorphization in the track core takes place already ina short period of about 10- 13 s, which is a novel modelfor the ion irradiation effect.
References
1) K. Kimura, J. Kaneko , S. Sharma, W. Hong , and N.
Itoh: Phys. Rev. B 60, 12626 (1999).
2) E. I. Rashba: in Excitons at High Density (Springer
Tracts in Modern Physics, Vol. 73), edited by H. Haken
and S. Nikitine, (Springer, Berlin, 1975) p.150.

159

RIKEN Accel. Prog. Rep. 34 (2001)

Ultrafast Luminescence of CsI Scintillator Crystals
under Heavy-Ion Irradiation
A.1. Popov, S. Sharma, and K. Kimura
During the last years , there has been a steady increase in the number of studies of CsI single crystals
due to the fact that at room temperature these crystals exhibits a fast ultra-violet (UV) emission at 300305 nm, of which the decay curve can be characterized mainly by two decay times , 10 ns and 35 ns. The
fast scintillation property with its high density andgood radiation hardness makes CsI one of the most attractive materials for high-resolution electromagnetic
calorimetry as well as for positron tomography. On theother hand, when CsI crystals are irradiated at nearliquid helium temperatures, the luminescence spectra
consist of two self-trapped exciton (STE) bands: singlet (290 nm) and triplet (340 nm) emissions. 1 ) The singlet band has two decay components of 2 ns and 100 ns
at 5 K , whereas the triplet band is composed of 0.6 and20 I-LS components.
In this paper, we report the results for pure CsI crystals, irradiated by several kinds of ions: He, N, Ar ,and Xe ions accelerated to 2.0MeV /nucleon. Luminescence decay and time-resolved spectra have beenmeasured using a single-ion and single-photon coincidence (SISP) system. 2 )The main results can be summarized as follows:(1) We have found ultrafast « lOOps) broad luminescence (200- 400 nm) .
(2) Over this broad luminescence, a narrower but intense band rose precipitously at 300 nm and was also
ultrafast « 100 ps). Its decay curve was followed bya slower decay component, which formed a retarded
peak at low temperature. Neither broad nor narrowultrafast luminescence (UFL) has been found thus far,while the slow component can be assigned to the known
STE. The UFLs may be ascribed to electron-hole interactions and plasma formation in the ion track coreand its surrounding.
(3) We have found that UFL was almost independent of temperature. As an example, the time-resolved
luminescence spectra of CsI irradiated with N ionsat 70 K are shown in Fig. 1. As evident in Fig. 1,
prominent UFL at 300 nm coexists with less-intensive
and slow triplet STE emission , whereas only the latter one can be observed under conventional irradiation
conditions. 1 )At room temperature , the 300 nm band has been observed more than once under the electron, , -, VUV-

160

c 2

o ns

.~

0.13 ns
0.5 ns
1 ns
1.8 ns2.8 ns

~

....=

o
200

300

400

wavelength (nm)Fig. 1. Time-resolved luminescence spectra of CsI irradiated by N ions at 70 K.

or X-photon irradiation, but reported decay times are
slower than 10 ns. All traditional excitation sources
are insufficient in providing the necessary excitation
density to create multiple e-h pairs nearby. For example, recently the 300 nm band has been studied by aFrench research group3) using the most powerful soft
X-ray laser with the specifications, 6 x 10 12 photons
3of 58.5eV/pulse- 5 x 10- 2 eV/A . In our case, the excitation density in an ion track core of 5- 10 A diame3
ter is approximately 6- 20 eV / A , which is three ordersof magnitude higher. This is why the use of heavy
ion irradiation of such high excitation density leads tothe formation of a principally new luminescence substance, which has emission decay components shorter
than lOOps.
The finding of the ultrafast decay component in 300nm emission is very important not only for the physics
of incipient track effects and electron-hole plasma formation in insulators , but also for further applicationsof CsI as scintillator detectors.
References
1) R. Lamatsch et al.: Relv . Phys. Acta 45 , 20 (1972).
2) K. Kimura and J. Wada: Phys. Rev. B 48,15535 (1993).
3) P. Jaengle et al.: J. Appl. Phys. 81, 2406 (1997).

RIKEN Accel. Prog. Rep. 34 (2001)

Photoconductivity of Nonconductive Oxides:
Search for Electric Conduction under Ion Irradiation
N. Matsunami and K. Kimura
When insulating or nonconductive oxides are exposed to ion irradiation, holes in the valence band
(VB) and electrons in the conduction band (CB) are
generated by electronic excitations. It is interesting toinvestigate whether the holes in the VB and/or electrons in the CB are electrically conductive or not. If
these carriers are not conductive, the electric charge
may accumulate and the surface potential may not be
zero against the ground during ion irradiation, unlike
metals. A nonzero surface potential may cause inaccurate measurements of the beam current and lead tomisleading results of the secondary charged particle
emission yields.
We have measured the current induced by photon
irradiation using a D2 lamp, a grating in a vacuumof rvO.l Torr and an electrometer (KEITHLEY 6517).
Au of rvl00 nm was deposited as electrodes on which
Cu leads were attached using Ag paste. The separation between the two electrodes was rvO.1 cm. Figure 1
shows the result of SrTi0 3 (STO). It appears that thephotocurrent was nearly proportional to the appliedbias voltage. The maximum conductivity for STO andMgO was evaluated as 3.6 x 10- 8 Scm- 1 at 200 nm and10- 9 Scm- 1 at 190 nm, respectively. Here, the thickness d of the effective layer for photon absorption or
carrier generation is taken to be the photon wavelength
at which the photocurrent takes its maximum.
We have calibrated the light intensity I (Fig. 2).
The electron-hole concentration n can be estimatedby n = IadT/v rv l0 8 (cm- 3) at 200nm, where I =3 X 10 12 photons/s, ad is assumed to be 0.1 (a = absorption coefficient and d = 200 nm) , T = lifetime ofelectrons and/or holes (taken as rv ns) and v = volume
of carrier generation (circle of 5 mm diameter multiplied by d = 4 X 10- 6 cm 3). Then, the mobility {t isevaluated as rv103 cm 2 /Vs and this value is comparable with that of Si. In conclusion, the carrier mobility

30
.1

25

:? 20
S:

I-

z 15
w
a::
a:: 10:::::>()

5•

STO (9.5 V)

-

•

•
• •

.

•..........~ ...

..!
0
100
200

-

300

400

500

600

WAVELENGTH (nm)Fig. 1. Photocurrent vs. photon wavelength for SrTi03 at
an applied bias of 9.5 V.

3

•
•
••

en
...... 2.5~0......

2en

z 1.5-

0
0

I-

:r:

•

a...

0.5

•

qo;-- 200...............
.........

•

I

I

300

400

. . . . . . . ....

500

600

WAVELENGTH (nm)Fig. 2. D2 lamp intensity at a sample position as a functionof photon wavelength.

in CB of STO is adequate for electric conduction during ion irradiation. Investigation of the carrier density during ion irradiation, and measurements below
200 nm and of other oxides are under way.

161

RIKEN Accel. Prog. Rep. 34 (2001)

Recent Progress in Biological Electron Transfer Studies
by the Method of Labelled-Electron with Muons:
Cytochrome c Oxidase
K. Nagamine, F. L. Pratt ,* l S. Ohira, 1. Watanabe, S. Yoshikawa,*2 K. Shinzawa-Itoh,*2 and T. Tsukihara*3
In order to obtain microscopic information about
electron-transfer in the biological macro-molecule, theJ.LSR method offers a great potential. During theslowing-down process, the injected J.L+ picks up one
electron to form a neutral atomic state called a muonium. The muonium is then thermalized followed bychemical bonding to a reactive site on the molecule.
Then, depending upon the nature of the molecule, theelectron brought-in by the J.L+ can take on several characteristic behaviors including a localization to form aradical state and/or a linear motion along the molecular chain. These behaviours, by setting the time-originof electron movement, can be detected most sensitively
by measuring the spin relaxation process of the J.L+
using the J.LSR method, which occurs through a magnetic interaction between the J.L+ and the moving electron produced by the J.L+ itself (the method of labelledelectron with muons).
The experimental studies on a series of representative proteins conducted by the RIKEN-KEK-Oxford
group mainly at RIKEN-RAL Muon Facility has revealed so far the following important new aspects ofelectron transfer in proteins.1 ,2)(i) For the muon-produced electron, topologically linear motion exists along the chain of both cytochromec and myoglobin. The intra-site diffusion rate along
chain D II takes on a value on the order of 10 12 rad/s,
and is almost temperature independent. The cutoff
process of the linear motion represents a departure ona longer time scale from the one-dimensional diffusion
which occurs on a shorter time-scale. Thus, one canobtain the inter-chain diffusion rate, D.1' The obtained
D.1 in cytochrome c is dominated by two different process, as can be seen in the temperature dependence.
The characteristic change at 200 K of D.1 seems to berelated to the well-known structural change of glasslike transition. On the other hand, D.1 in myoglobin
shows only one component, reflecting the different protein dynamics of this molecule for inter-chain electrontransfer.
(ii) Positive muons, as evidenced by the preliminaryparamagnetic measurements as well as theoretical calculations, stop preferentially at the negatively charged
sections near to the heme-Fe atom.
(iii) The characteristic electron transfer phenomena in
the form of l/B dependence was not seen neither in*1 Oxford University, UK*2 Himej i Institute of Technology*3

162

Institute for Protein Research, Osaka University

lysozyme nor in cytochrome c with Fe(2+) where electron transfer is known not to exist.
In the present experimental studies conducted at
RIKEN-RAL Muon Facility, we challenged to explore
electron transfer in the cytochrome c oxidase, which
(a)
30

300K

10

-

3

' C/')

.§,
H

0.3
•
A

•

Myoglobin
Cytochrome c
Cytochrome c oxidase

0.1

100

30

300

1000

3000

Magnetic Field (G)

(b)
10

0.1

0.01

• 300 Ko 150 K
A
40 K
o

5K

0.001 L . . . - - _...........' - -_ _
10

~-'--

_ _ _- - ' -_100___'.......

1000

Magnetic Field (G)Fig. 1. (a) Observed muon spin relaxation parameters under various external magnetic fields on three typical
proteins at room temperature. (b) Same as Fig. 1 (a)for cytochrome c oxidase at various temperatures.

is known as a terminal protein situated at the final
part of mitochondria aspiration chain. Recently, structure studies have been carried out by using a highresolution X-ray studies. 3 ) Due to the difficulty in thesample preparation, the actual sample is composedof the Bovine heart cytochrome c oxidase (50%) andthe surfactant material Deyl-f3-D-maltoside and buffer
chemicals of NaH 2 P0 4 (altogether 50%).
The results are shown in Fig. l(a) and (b) in terms of
the external field dependence of the relaxation parameter (r) obtained by a fit to the data with the RischKehr function representing a relaxation function due toa lineraly moving electron. The following conclusions
are readily obtained:(1) at room temperature, electron transfer along thechain in cytochrome c oxidase is very much suppressedcompared to these in cytochrome c and mioglobin.
(2) by reducing temperature, the electron transfer
along the chain becomes evident, in particular, below

150K.
The results may contain contributions of the signals from either surfactant or buffer. Since there exist several heme centers, there might be corresponding
signal components. The extended studies are now inprogress.
References
1) K. Nagamine: Bull. Mater. Sci. 22, 485 (1999).
2) K. Nagamine et al.: Physica B 289/290, 631 (2000).
3) T. Tsukihara et al.: Science 269, 1069 (1995).

163

RIKEN Accel. Prog. Rep. 34 (2001)

Metal Uptake Mutant of Yeast Schizosaccharomyces pombe
Y. Nose* and 1. Yamaguchi
taining 1362.2 Bq of 7Be, 18.6 Bq of 22Na, 95.2 Bq of
46SC, 313.2 Bq of 54Mn, 83.1 Bq of 56Co, 1063.2 Bq of
65Zn, 205.5 Bq of 75Se, 3372.8 Bq of 83Rb, 3024.0 Bq of
858r, 1886.4 Bq of 88y, 1318.8 Bq of 88Z r , and 14.1 Bqof 95mTc, was added to the cell suspension. After 30
min, cells were collected, washed 3 times with distilledwater, and subjected to gamma-ray measurement andprotein assay. Figure 1 shows the metal uptake ability of the transformant, designated REMI 7-4. In thepresence of glucose, REMI 7-4 took up Sc, Se, Rb , andZr at higher levels than control. Uptakes of other metals by the transformant were same with wild type. On
the other hand, in glucose absent condition, REMI 74 took up Co at lower levels than wild type, and no
significant changes were observed in other metals. Little are known about the uptake mechanisms of 8c, 8e,
Rb, Zr and Co. Therefore, the transformant should be
the key to analyze the mechanisms. The gene(s) disrupted by REMI event still remained to be identified.
The next step is molecular biological analysis of themutant.

The disposal of radioactive wastes and nuclear facility accidents are serious social problems. To reduce
the radionuclides in environment, metal uptake activity of various living organisms has received attention.
Recently, we demonstrated by using the multitracer
technique that the yeast Saccharomyces cerevisiae andSchizosaccharomyces pombe has ability to take up various radionuclides. 1- 3) To determine the metal-uptake
mechanisms in yeast , S. pombe, transformants weremade and their metal uptake abilities were measured.
The S. pombe transformants were made by restriction-enzyme-mediated integration (REMI) method,using blastisidin-S resistance gene (BSD) as a marker.
Among about 700 transformants, a mutant having
high metal uptake abilities was selected by multitracer
technique. The multitracer uptake assay was done asfollows. Wild type and transformants of yeast were cultured in 1.5 ml of YEL medium. Cells were collected bycentrifugation at 1,000 xg for 5 min. Cell pellets weresuspended in 1 ml of 10 mM HEPES buffer (pH 6.0)
with or without 3% glucose, and incubated at 25°C
for 30 min. Ten jiJ of the multitracer solution conSc- 46

Mn- 540.05.------,

0.2 ,..-------,

Co- 560.03 . . . - - - - - - ,0.2

0.041------+-i

0.18 1-=-----1
0.15 Hil'!a'~---I

0.02 H~'f"f""l'---I

0.15

0.03 1----+-1

0.1

0.02

x 0.05

0.01

Be- 7

0.25
c:

.~

ec.
Cl

::t
"0'
III

b

Zn- 65
0.6 , . . - - - - - - ,

0.02

il

0.01
0.01

1,1

O .............L.L......L...........~

3% glucose

-+

--

Se-75

0.04 ,..------,-+

Rb- 830.7 . - - - - - - ,+Sr- 85

0.6 I - -__- - - i~

0.03 1----:;:--+-'f'T"H

0.5

~

0.02

0.4

0.1 5

i1

0.02

0.3

0.1
0.05

o

~.IoL-~""'-""

1.2 , . . - - - - - - ,- 0-+- - Zr- 88
0.7 . . . - - - - - - ,0.6~--""'t"'-I

0.2

0.2
0.1

Y - 880.25 , . . - - - - - - ,'B 0.03 I----.,--T-i"--+- - -

-- --

--

I~

0.81---+-1..=:-

0.5 I----+-..-Ml
0.4 I----+-p- H

1-

~

0.6

0.31---~

0.4

0.2

0.2

o

0.1
1I:O.:iI.U-.L........~

o Ci'
(j

3% glucose-+---+- - --+- - -

1)0-

.s~

Ci'

1)0-

.s~

§~§~

-+- - -

~

(j

~

-- -+

Fig. 1. Uptake of various radionuclides by REMI 7-4. Data represent the gamma-ray activity (Bq) per
microgram of cell protein.

References
1) Y. Nose et al.: RIKEN Accel. Prog. Rep. 31,141 (1998).
2) Y. Nose and I. Yamaguchi: RIKEN Accel. Prog. Rep.
32, 128 (1999).
University of Michigan Medical School, USA

1643) Y. Nose and I. Yamaguchi: RIKEN Accel. Prog. Rep.
33, 137 (2000).

RIKEN Accel. Prog. Rep. 34 (2001)

Influence of Nonpathogenic Fusarium Strains
on Uptake of Radionuclides by Tomato
T. Soshi, T. Arie,* and 1. Yamaguchi
Radionuelides released into the environment enter
the food chain through, e.g., plants and fish , pose a potential risk to human health. Eliminating the radionuelides from the soil environment or reducing their uptake by food crops would decrease the dose to humans.
The possibility of phytoremediation was suggested toreduce the radionuelides in the soil. Transfer of radionuelides from the soil to the plant varies depending on soil characteristics and plant species. 1 ,2) Rhizosphere microbes are also often known to affect theuptake of radionuelides from the soil by the plant. 3 ,4)However, the influences of microorganisms on the uptake of radionuelides by plants remain to be elucidated.
Aiming at phytoremediation of soils polluted with radionuelides or at increasing the uptake ability of plants,
we have analyzed the effect of microbes on the uptake by the plant using the multitracer technique. 1 ,2)Tomato is one of the plants capable of uptaking andaccumulating radionuelides. We found that a tomato
pathogenic strain of Fusarium (F. oxysporum, F. spio
rycopersici) can enhance the uptake of Sr and Cs by
the plant through infection. 3 ) In this paper, we reporton the influences of nonpathogenic strains of F. oxysporum, F. spio rycopersici (N.P.F.) on the uptake ofradionuelides using the multitracer technique.
N.P.F. (TI , T2, T3, MI, and M2) were isolated fromtomato rhizosphere. Tomato seeds were sown in plastic pots containing 150 g of sterilized horticultural soil
(Kureha engei baido, Kureha Chemical Industry Co. ,Tokyo). N.P.F. were cultivated on potato dextrose
broth at 25°C for 1 week until sufficient spores wereformed. The tomato plants were cultivated in a greenhouse at 25-30°C and under 15,000 to 17,000 lux lightfor 12 hrs a day. N.P.F. liquid cultures were drencheddirectly to the soil for inoculation. Two weeks after
seeding, a mixture of diluted multitracer and radioactive cesium (137 Cs) was applied to each pot. The sameamounts of solution were absorbed by filter paper forcomparison. In the two weeks that followed , the aerial
parts of the plants were collected and dried at 50°C.
Then the radioactivity was meas·u red using a hyperpure Ge detector and the results were expressed as theuptake percentage with respect to the initial tracer activity per gram dry weight of the plant.
Figure 1 (a) and (b) show the uptake rate of several elements from the soil to the aerial parts of theplant (Na, Mn, Co, Sr and Cs in Fig. 1 (a); Zn, Tc and
Rb in Fig. 1 (b)). The tomato plants treated with TI
showed moderate enhancement of the uptake of Na,
Faculty of Agriculture, Tokyo University of Agriculture andTechnology

(a)
2

~

oJ::

en

·w
~

~ 1.5
"0

en

........

e

1

....
Q)

e
Q)

~

ro

~ 0.5

=>

0

Mn

Na

Co

Sr

Cs

Nuclide

(b)

30

~

.J::

en 25

·w
~

~

20

-0

Cl

........

e

15

....

Q)

e

10

Q)
~

....ro

0.

=>

5

Zn

Rb

Tc

Nuclide0: Control

Ill: T1

II: T2. : T3

13: MI

Ii! M2

Fig. 1. (a) Uptake rate of five elements by tomato inoculated with nonpathogenic strains of Fusarium. (b) Uptake rate of three nuclides (Zn, Tc and Rb) by tomato
with nonpathogenic strains of Fusarium. Data is expressed as percentage to the activity of the control pergram dry weight of the plant that inoculated with nonpathogenic strains of Fusarium (TI, T2, T3, MI and
M2). Error bar shows standard deviation.

Co , Cs and Rb. The uptake rates of Sr and Zn were
almost the same as that of the control and the Mn
uptake rate was less. T2 increased the uptake of thesame elements as TI as well as Tc. MI and M2 enhanced uptakes of Co, Cs and Rb. M2 also increased
Sr uptake. T3 showed significant increase in the uptake in all elements except for N a. Enhancement of
the uptake of both Sr and Cs was observed in T3 andM2-inoculated tomato. In terms of phytoremediation
for contaminated soil by long-lived radionuelides suchas Sr or Cs, the use of microbes like N.P.F. T3 or M2
to enhance uptake of these elements by plants is sug-165

gested.
References
1) S. Gouthu et al.: RIKEN Accel. Prog. Rep. 30, 117(1997).

166

2) S. Gouthu et al.: J. Radioanal. Nucl. Chern. 222 , 247(1997).
3) S. Gouthu et al.: RIKEN Accel. Prog. Rep. 31 , 146(1998).
4) J. A. Entry: Water, Air Soil Pollut. 88 , 167 (1996).

RIKEN Accel. Prog. Rep. 34 (2001)

Variation in Sensitivity to Radiation of Orchid Genetic Resources
K. FUrukawa,* M. Kubota,* T. Abe, and S. YoshidaOrchids are the largest family of higher plants. However, only a few genera of orchids are used for horticultural purposes. Breeding of these orchids has been
conducted for more than 100 years and new varieties
are released every year. Heavy-ion irradiation is oneof the interesting methods of mutation breeding. The
effect of N-ion irradiation on mutation breeding of orchids was investigated in this study.
Eight varieties of Cymbidium, nine of Odontoglossum
alliances (eight of Odontioda and Vuylstekeara), threeof Zygopetalum, Epidendrum and Oncidium were used
for heavy-ion irradiation. The protocorm-like body
(PLB) was cut to half or a quarter of its size and then
15 pieces of cut PLB were placed on a Petri dish with asolid medium containing Hyponex 20-20-20 (Hyponex
Japan, Osaka, N-P-K=20-20-20), sucrose and a gelling
agent. Each experiment was repeated at least once or
twice. Irradiation treatments of the PLBs were conducted in the dose range of 5 to 100 Gy with 14N ions.
After irradiation, PLBs were transplanted to Erlenmeyer flasks with Mukoyama original medium. Theseflasks were put in the culture room at 20 to 25°C witha 16 h light/8 h dark fluorescent illumination for 3 to 5

months. Then, the number of green-colored PLBs andelongated shoots was counted and a survival rate wascalculated.
PLBs of Cymbidium 'Red Angelica' were used todetermine the survival rate in the dose range of 5 to
100 Gy (Table 1). PLBs could not survive at doses
over 50 Gy. The 50% lethal dose (LD5o) value was
9.2 Gy. The LD50 value of 'Sweet Devon' was lower
than that of 'Red Angelica,' and those of 'Procyon'
and 'In The Mood' were higher. The LD50 values ofthe other four cultivars were almost the same as thatof 'Red Angelica.' In the case of Zygopetalum, 'PrettyAnn' and 'Fire Kiss' have the same parents, however
the radiation sensitivity of these cultivars was different. Shoots were differentiated from surviving PLBsof most orchids at doses under 20 Gy. Odontoglossum
alliances was lesssensitive to radiation than the othergenera examined.
Already, orchid plants from the irradiated PLBs
have been grown in the greenhouse. FUrther observations are needed to determine the change of phenotype
in the flowers of those juvenile plants.

Table 1. Effect of 14N heavy-ion beam irradiation on frequencies of survival of orchid genera.
Dose (Gy)Survival (0/0)

Cl!!!.bidium.
Lady Fire'Red Angelica'

0
5
10
20
50

100
85
55
15
0

Enzan Stream' Orpheus'

New Century'Coronation'

Enzan Spring'In The Mood'

Melody Fair
'Marilyn Monroe'

Pearl Dawson'Procyon''Devon Odyssey ''Sweet Devon'

100
90
50

100
95
40
-

100
95
80

100
85
45

100
95
90
60

100
100
60
20

72

-

14
0

0

-

-

Odonlioda

0
10
20

0
5
10
20
50

Lovely Penguin'Fides'Lovely Apple'Ruby Castlehill'

Sleeping Parade'Orange Sunset'

Lovely Morning'Sayaka'Peter Timoney'Kurara'Nationhood'Bossa Nova'

Starlit Night'Fancifully'

100
84
48

100
82
74

100
100
80

100
96
80

100
68
36

100
76
40

100
100
15

Odonlioda

Vu!!.!slekeara

Frontispiece'Anbelo'

Cambria' Golden Gate'

B.G. White'Bogey'Z~~~"'~lll
Redvale'Fire Kiss'

Redvale'Pretty Ann'

100
70
64
35

100

100
88
52
4

100
80
40
0

100
100
80
32

-

88
80

-

-

-

Epidendrum

Oncidium

100
85
60
40

100
75
40
0
-

Mukoyama Orchids Ltd .

167

RIKEN Accel. Prog. Rep. 34 (2001)

The Effects of Heavy-Ion Beam Irradiation on PLB Developmentin Several Orchids
K. Tokuhara,*l T. Abe, K . Miyoshi,*2 and S. Yoshida
Breeding of Orchidaceous plants has been conductedby hybridization for more than 150 years. This takes along time due to the slow growth of the orchid. More. over, it is impossible to obtain cultivars by hybridization which have the minimum change of a certain characteristic, such as color of flower. Thus, mutation
breeding has been conducted as a useful method for theestablishment of new cultivars with minimum changes
from the original cultivar in many plant species. Recently, establishment of new cultivars using heavy-ion
radiation as an alternative method of mutation breeding has been reported. In the present study, we investigated the effect of heavy-ion beam irradiation on
protocorm-like body (PLB) development in several orchids.
PLBs of Laelioeattleya (Le.) Melody Fair 'Summer King. ' Oneidium (One.) obryzatum, One. sp. ,and Phalaenopsis (Phal.) Wedding Promenade 'Purple Queen,' which were micropropagated by shoot tip
culture, were used. Fifty PLBs were placed in a plastic Petri dish (6 cm in diameter) containing 5 ml New
Dogashima medium supplemented with 10 giL sucroseand 1.5 giL gellum gum as a gelling agent. The media
were adjusted to pH 5.4 before autoclaving at 120°C
and 1 kg/cm 2 for 15 min. Then, these PLBs were irradiated with 14N or 2oNe-ion beams (135 MeV lu) inthe dose range of 5 to 50 Gy. Two to five replications
were made for each treatment under the present con-ditions. Three weeks after the irradiation, PLBs were
subcultured in square bottles containing fresh medium.
Frequencies of PLB mortality were measured 1, 2 and3 months after irradiation in Le. and 3 months in theother genera.
After irradiation, the frequency of PLB mortality increased with increasing absorbed dose as well as prolongation of the culture period in all genera examined(data not shown). However, the frequency of mortality did not increase after a culture period exceeding three months post-irradiation. Moreover, no significant difference in mortality for Le. was observed
between treatment with 14N and that with 2oNe-ion(Table 1). In One., all PLBs showed necrosis after irradiation with a dose higher than 50 Gy. Phal. washighly sensitive to the treatment . In fact, more than
62% of the PLBs exhibited necrosis after a dose higher
than 5 Gy. Differentiation and growth of shoots fromsurviving PLBs excluding Phal. after 50 Gy exposure
were slower than from PLBs after lower doses (0, 5, 10
and 20 Gy). Mutated shoots from surviving PLBs in
the case of exposure to more than 10 Gy were observedin Phal.
In our subsequent experiments we are investigating
the effect of irradiation on the growth and characteristics of flowers, in terms of shape and color in the
blooming season in our greenhouse.

Table 1. Effects of heavy-ion beam irradiation on PLB development in sev~ral orchids.

One. obryzatum

One. sp.

0.8 ± 0.4

6.9 ± 2.3

Phal. Wedding Promenade'Purple Queen'
027.9 ± 6.9

12.1 ± 0.9

62.4±5.1

10

25 .4 ± 3.4

30.3 ± 2.7

76.4 ± 3.3

2051.0 ± 4.9

40.7 ± 2.7

84 .8 ± 2.5

5072.4 ± 2.4

60.4 ± 6.0

89.6 ± 2.4

523.8 ± 7.2

2.0 ± 1.4

10

26.8 ± 5.3

16.0 ± 3.9

20

59 .3 ± 4.8

68.0 ± 7.0

5086.3 ± 1.2

100.0

Ion

Gray

Control

0

Le. Melody Fair
'Summer King'6.0 ± 4.2*

N

5

Ne

* Frequency of mortality (%)

*1
*2

168

Dogashima Orchid Center
Faculty of Bioresource Sciences, Akita Prefectural University

RI KEN Accel. Prog. Rep. 34 (2001)

Mutant Flowers of Dahlia (Dahlia pinnata Cav.)
Induced by Heavy-Ion Beams
M. Hamatani,*1 Y. Iitsuka,* 1 T. Abe, K. Miyoshi,*2 M. Yamamoto,*3 and S. Yoshida
Radiation has been widely adopted in order to induce artificial mutations in various plant species easily
and effectively. In our previous research,1-3) we irradiated dahlias with ,,-rays to induce mutations for new
agronomic traits such as a high productivity of cut
flowers in winter. However, we obtained only mutants
with limited color variations, which were assessed withpoor marketability. Moreover, promising phenotypesof mutations which were selected in the growing season following the irradiation treatment were not stablein the next season and thus we did not obtain any mutants with genetically stable features. Therefore, we
conducted an experiment using treatments of heavyion beams as an alternative method for the inductionof dahlia mutations which were more stable and morevaried than the ones induced using ,,-rays .
Irradiation treatments were conducted on the small
shoots (approximately 1 cm in length) of the pinkflower dahlia cv. 'Miharu,' which were grown in a modified Murashige-Skoog medium, in the dose range of 5,
10, 20, 50 and 100 Gy for N-ions. We did not obtain
distinct experimental results for those plants treatedwith more than 20 Gy due to their poor growth invitro. Plants treated with 10 Gy grew vigorously invitro as well as in the experimental field , and showed
the highest frequency of mutant induction.
The results obtained under experimental field conditions with an increase in exposure dose are as follows:(1) decrease in the frequency of anthesis, (2) increasein the variation of flower diameter, (3) increase in thevariation of flower colors and (4) increase in the malformation of flowers. On the other hand, irradiation
had little effect on the time of flowering , the length offlower stalks and the frequency of appearance of sidefacing flowers.
Flowering frequencies after 5 and 10 Gy apparently
decreased compared with those after 0 and 1 Gy. The
decrease in the flowering frequency with the increasein the exposure dose has also been observed in thetreatment of ,,-ray irradiation. As for floral diameter,
those of 3- 12 cm have been observed. Under the 0 to
5 Gy doses, the percentage of flowers with a diameter of 9- 10cm was 80%, but under lOGy, it was 55%
and the number of flowers with a diameter of either
less than 8 cm or more than 11 cm increased. The mutants, such as those with darker- or paler-colored petals
or white-tipped petals were observed in the present
Hiroshima City Agriculture and Forestry Promot ion Center
Faculty of Bioresource Sciences, Akita Prefectural University*3 The Hiroshima Botanical Garden

Fig. 1. Variation of mutations. (Arrow indicates a typicalflower of ' Miharu.')

OGy

y

lOGy

*1

*2

Fig. 2. The analysis for floral colors of the mutants using
a chromameter.

169

experiment (Fig. 1) as well as in our previou's experiment with ')'-ray irradiation. Mutants with darkercolored flowers were more commonly observed in N-ion
irradiation than in ')'-ray irradiation. The frequencyof mutants with darker-colored flowers is higher thanthat of mutants with paler ones. The analysis for theflower color using a chromameter (MINOLTA CR-300)
revealed that the mutations of flower colors after 5
and 10 Gy showed two clusters (Fig. 2). More thanten clones were selected as promising strains for themarket , such as clones with flowers having pink-tipped
or white-tipped petals, those with paler-colored anddarker-colored petals and so on. Because changes in170

the flower traits are sometimes observed in dahlias dueto their chimeric characteristics, further experimentation should be conducted to evaluate the stability ofthese promising strains.
References
1) A. Takai: Ann. Rep. Hiroshima City Agric. For. Prom.
Cen. (Hortic. Sect .) 1997, 115.
2) A. Takai: Ann. Rep. Hiroshima City Agric. For. Prom.
Cen. (Hortic. Sect .) 1998, 80.
3) Y. Iitsuka: Ann. Rep. Hiroshima City Agric. For. Prom.
Cen. (Hortic. Sect.) 1999, 89.

RIKEN Accel. Prog. Rep. 34 (2001)

A New Method for Induction of Mutation in Wheat and Barley
Using Heavy-Ion Beams
1. Ronda, * M. Wada,* T. Abe, T . Asami, and S. Yoshida

Recently, heavy-ion bombardment (RIB) of plants
has been investigated to obtain a certain mutant . Abe
et al. extensively studied and established the application of this method to tobacco plants to obtain amutant. 1) Applications of this method to other plants
such as rice 2) and rose 3 ) were also studied, however,those to wheat , barley, and maize have not yet beenreported. In this study, RIB applications to wheat andbarley to obtain a certain mutant were investigated.
The Japanese breeding line of barley ( Hordeum vulgare L.) , Kantohadaka 77 (K77; six-rowed, naked cariopsis, uzu, waxy endosperm) was used as a plant material. Both imbibed (12 hr, 20°C) and dry seeds were
irradiated by 14N-ion beams (135 MeV lu) at a dose
range of 5 to 400 Gy and grown in the field. The culture
condition was not appropriate for barley; only 21.4% of
the plants survived even in the control (without RIB)
culture. RIB of barley of more than 20 Gy to the imbibed seeds and 200 Gy to the dry seeds severely inhibited their growth. Thus, their M2 seeds were not obtained. The M2 seeds were harvested separately fromeach plant from seeds subjected to lower dose treatments and albino plants were observed from the imbibed seeds subjected to 5 Gy treatment and dry seeds
subjected to 10 and 20 Gy treatments. These results
indicate that in the RIB of bar ley, the optimal dosesof irradiation are 5 Gy for imbibed and 50 Gy for dry
seeds (Table 1).
In the experiment on wheat (Triticum aestivum L.) ,a Japanese bread wheat cultivar, Bandowase, was used
as a plant material. Both imbibed (24hr, 4°C) and dry
seeds were irradiated using the same method as thatfor barley. Treated seeds were sown and cultivated totheir two-leaf stages, and then their growth was examined. The growth of imbibed seeds subjected to morethan 20 Gy RIB and dry ones subjected to more than
200 Gy RIB was severely inhibited (Table 2). The optimal doses for wheat may be 10- 20 and 100 Gy RIB
of imbibed and dry seeds , respectively.
The M2 barley seeds were mixed according to theirabsorbed doses , aliquots of them were cultivated, andplants with a short culm were observed. In total, 15
plants with a short culm were selected as putative mutants. Some of these plants were selfed as well as
crossed with K77 andlor Misatogolden (Misato) , andphenotypes of M 3 , F 1, and F 2 plants were examined.
Among the 15 putative lines with a short culm, one
severe dwarf line (d3, selected from 100 Gy RIB dry
seeds) , and two semidwarf lines (d4 and d5, which

Table 1. Effects of RIB treatment on barley.
Imbib e d seed t rea t me nt
Dr y see d tr eatm e n t
N ormalA lbin o
Ab s orb e d
N o rma l
Albin oA bsorb e ddose ( G y)
pl a nts ·pl a nt s **dose (G y)p la nt s*
p l a nt s··5
111 (11.1)
1
10
1 3 1 ( 16 .9)1
10
12 (1.2 )020
1 2 4 ( 16 .0 )1
20
0 (0 )
050
7 6 (9 .8)
0
50
0 (0)
0
100
3 9 (5.0 )0100
0 (0 )
0200
0 (0 )
0
Go n t9 ( 21 4)
0
400
0 (0)
0
* Numbe r o f p l a nt s s h OWIn g n o rm a l g r o w t h ( r ate (%) In p a r e nth es Is)** Num be r o f M 2 lines wi t h al b i n o pl ants. C o n t . : control.
Nu mbe r o f seeds sow n : i mbibed HIB 10 0 0. dr y HIB 777 . Co n t . 4 2.

Table 2. Effects of RIB treatment on wheat.
I mb ib e d see d tr eatm e nt
Dry seed tr eatm e nt
A bso rb ed
N o rm a l
Abso rb e d
N o rma ld ose ( Gy)plant s (%)*
dose ( G y)p l ants (%)*
5
88 .3
10
91. 1
20
8 2, 1
10
91
50
7 9,3
20
51
50
4. 5
100
71. 7
200
0,5
1 00
2 .4
200
0
400
0
Cont ,
Con t.
84.6
9 1. 2* R ate o f p la n ts show i n g n or m a l grow t h . Co nt. : Co ntrol.

Table 3. Segregation of F2 plants.
Cross

K 77 X d 3
Misato X d4
K 77 X d 5
Mi sato X d5

Mu ta nt

No r m a l

T ot a l

X 2 valu e

Pr oba-pl a nt *pl a n t*

pl ant*(1:3)

bility

8
8
2
.9

24
23
7
30

32
31
9
39

0
0.01
0.04
0.08

1
0.92
0.85
0.78

*Nu m be r of p l ants. K77 : K a nt o h a d a k a 77 . Mi sa t o : M isat ogo lde n .

were selected from 50 Gy RIB dry and 5 Gy RIB imbibed seeds, respectively) whose leaf expansion is imperfect, were selected as homozygous phenotypes for
short culm. Phenotypes of F 1 among these three lines
and K77 and Misato were the same as those of K77 ,and Fl between K77 and Misato. All their F2 segregated into mutants and normal plants with a 1:3 ratio,suggesting that all of these three lines are single-generecessive mutants (Table 3).
These results clearly demonstrate that RIB is effective for the induction of mutation in barley. This
unique method may contribute to the development of
a novel mutant for crop improvement in the near future.
References
1) T. Abe et al.: in Modification of Gene Expression andNon-Mendelian Inheritance, edited by K. Oono and F .
Takaiwa, (National Institute Agrobiological Resources,
1995) , p.469.
2) T. Abe et al.: RIKEN Accel. Prog. Rep. 32, 145 (1999) .
3) T. Kitaura et al.: RIKEN Accel. Prog. Rep. 33, 141(2000) .

National Agriculture Research Center, Ministry of Agriculture, Forestry and Fisheries

171

RIKEN Accel. Prog. Rep. 34 (2001)

Chromosome Breakage in Wheat Induced by
Heavy Ion-Beam Irradiation
H. Tsujimoto,* T. Yamada,* and T. Abe
Because of polyploidy, common wheat (Triticum
aestivum L. 2n = 6x = 42) is tolerant to chromosomal
aberrations. Many aneuploids and chromosomal deletion lines were produced in this species and used tomap genes on a certain chromosome or chromosomal
region. We here aim to produce 'micro-chromosome
deletion lines' that carry smaller deletions. These lines
must be useful in future to isolate and identify wheat
genes by map-based cloning method. It is reported
that irradiation of heavy ion-beam caused 10 bp- to
10 kb-deletions. Thus, we chose this treatment, insteadof chemical mutagen that mainly causes base changes
of DNA.
Dry seeds of common wheat cultivar 'Chinese Spring' were irradiated with Nand Ne ion(135 MeV lu) within a dose range of 50 to 200 and of
25 to 100, respectively. The linear energy transfer of
the Nand Ne ion corresponded to 30 and 63 KeV Imm,
respectively. One month after sowing on nursery boxes
lOOjD--o-.a__~~------------1

with sterilized soil, the survived plants were counted.
Mitosis and meiosis were observed in the root-tip cells
and pollen mother cells, respectively. In mitosis, numbers of chromosome breaks were counted in which dicentric and ring chromosomes were regarded to be theproductions by two breakage events.
With the increase of dose, the frequency of survival
decreased (Fig. 1). The values of LD50 of Nand Ne
were 90 and 150 Gy, respectively. With dose increase,
numbers of chromosome breakage increased (Fig. 2).
Ne-ion beam induced chromosome breakage twice asmuch as N beam did. These data indicated that inwheat LD50 corresponds to 20 chromosome breaks.
In mitosis, multi-centric , dicentric, ring chromosomes
in addition to simply broken chromosomes appeared(Fig. 3). Appearance of micronuclei in interphase cells
indicated that breakage events were not healed yet. In
meiosis multivalent appeared, meaning many translocations were included in the plants (Fig. 4).
We found that the doses we irradiated were toostrong to produce micro-chromosome deletion lines.
We need to investigate plants irradiated with lower
doses.

~ r---------------------~--~

25

50

75

100

I~

150

175

200

Dose (Oy)Fig. 1. Survival of plants irradiated with N or Ne ion-beamon 30 days after the irradiation. Open and closed circles
indicate Nand Ne ion-beam irradiation, respectively.
Fig. 3. A mitotic metaphase cell of a plant irradiated with
N ion-beam at 100 Gy. Arrows indicate abnormal chromosomes.

60
50

140
~ 30 r----------------------J'-------1!20 r-----------~~--~~-------1.;
ZIO~------~~~~-------------1

25

50

75

100

125

150

175

200

Dose (Oy)Fig. 2. Number of chromosome breakage in plants irradiated with ion beam. Open and closed circles indicate
Nand Ne ion-beam irradiation, respectively.
Kihara Institute for Biological Research, Yokohama City
University

172

Fig. 4. A meiotic metaphase cell of a plant irradiated with
Ne ion-beam at 100 Gy. Arrows indicate multivalents.

RIKEN Accel. Prog. Rep. 34 (2001)

Dose-Dependent Effects of Heavy-Ion Beam Irradiationon the Testes of MiceA. Yoshiki, A. Kogiso, N. Hiraiwa, F. Ike, H. Nagase, C. Yoshida-Noro,
N. Fukunishi, Y. Yano, and M. Kusakabe
We investigated the effects of heavy ion beams on
the germ cells in testes quantitatively by immunohistological methods. C57BL/6J (B6) mice were deeply
anesthetized with nembutal solution, fixed on a plastic plate, and exposed to heavy ion beams in the testis
region of the body. The 12C, 14N and 2oNe-ion beams
were accelerated using the RIKEN ring cyclotron at
Linear Energy Transfer (LET) of 135 MeV /u. Histological damage and its recovery in the testes were
examined by conventional staining and immunohistochemistry. B6 males were sacrificed at 2, 5 and
10 weeks after heavy-ion beam irradiation, and theirtestes were removed and fixed in 4% paraformaldehyde solution. The tissues were rinsed in 0.1 M sodium
phosphate buffer (pH 7.4), dehydrated with ethanol
series, and embedded in polyester wax (B.D.H., England) or Technovit 8100 resin (Heraus Kultzer GmbH,
Wehrheim, Germany). Immunohistochemistry was
performed using germ cell stage-specific rat monoclonal TRA369 antibodies which can recognize testicular germ cells in stages from early pachytene spermatocytes to spermatids. 1) The degree of tissue damage and recovery of the seminiferous germ cells was
expressed by mean scores in three different regionsof the testis section as follows: recovery rate (%) =the number of seminiferous epithelial sections without
TRA369-positive cells/the total number of seminiferous epithelial sections x 100. Three mice were used
for each group.
Several weeks after irradiation, we noted that theblack coat hair gradually turned to white in the heavyion-beam-exposed region. Although heavy ion beams
were irradiated on the ventral side, the degree of hairpigmentation in both the ventral and dorsal skin was
reduced in a dose-dependent manner (Fig. 1 A). Thisfinding indicates that the 12C, 14N and 2oNe-ion beams
penetrated into and equally affected the inside tissues
such as those of the testes. Testis tissues were histologically examined at 2, 5 and 10 weeks post irradiation (Fig. 1 B). The degree of tissue damage was mostsignificant at 5 weeks in all the groups. Immunohistological staining of the testes with TRA369 antibodies
revealed seminiferous epithelial sections without dif-

Fig. 1. Change in the coat color and histological damage oftestis tissues after nitrogen ion irradiation. (1A) Degreeof redlJ.ction in hair color detected 28 weeks after irradiation. (1B) Histology of testes 5 weeks after irradiationof 1, 3, and 5 Gy.

llCion9(. . )
100

Fig. 2. Quantitative analyses of seminiferous epithelial
germ cells after heavy-ion beam irradiation. Please see
details in the text.

ferentiating germ cells. We scored the seminiferous
epithelial sections with or without TRA369-positive
cells and expressed the damage and recovery of thedifferentiating germ cells as the recovery rate in eachexperimental group (Fig. 2). These quantitative analyses indicate that histopathological effects of heavy ion
beams on the germ cells in the testes occur in a dosedependent manner, and that the type of the beam differentially affects the histology of testis tissues.
References
1) D. Watanabe et al.: Mol. Reprod. Dev. 33 , 307 (1992).

173

RIKEN Accel. Prog. Rep. 34 (2001)

Mouse Mutagenesis by Heavy-Ion Beam for the Profilingof Morphogenetic Genes
C. Yoshida-Noro , A. Yoshiki, M. Kusakabe,* T. Matsuyama, and H. Nagase
Mouse mutant archive is a useful resource for thefunctional genomics in the post-genomic era. We propose here novel systematic approaches for the production, screening, preservation and analysis of morphogenetic mutants (Fig. 1).
(1) Heavy-Ion Beam Mutagenesis
Since on-going ENU (N-ethyl-1V-nitrosourea) chemical mutagenesis primarily induces random single basesubstitutions, mutations in the genome do not necessarily represent as phenotypes. In order to increase the efficiency of phenotype assessment, we introduced a method using heavy-ion beams accelerated
by RIKEN Ring Cyclotron as a mutagen.1) As thismethod is expected to cause multiple types of mutation including point mutation, deletion and translocation, it is suitable for the analysis of multi-gene phenotypes such as cancer or developmental defects. It is reported that average size of deletion shows two peaks at
about 85 bp and 1,000 bp in relation to the nucleosome
structure. 2 ,3) Frequency of mutation in the genomeof a mutant strain (BI05) has been investigated andestimated at approximately 1.5- 5.0 x 10- 4 by using
RLGS 4 ) (restriction landmark genome scanning) and
SSLP (simple sequence length polymorphism) analysis.
(2) Fetal Phenotype Screening
Fertilization rate and birth rate are the key factors
for getting mutant offspring, which causes difficulty

Heavy Ion Beam Mutagenesis Project
Morphogenetic Genes
Hea':Vylqn
B.eam Irradiatioll

oo
. 00

" ••tl.

Aim

cro..

orlV~

re tu eleth.1
Fetal

Phenotype
Screening
03

Fig. 1. Schematic overview of HIB mutagenesis project.

Present address:

School174

in an effective accumulation of the mutation resource
through the analysis of the born offspring. In order toovercome this problem, we apply the phenotype screening at the fetal stage either at G3 (recessive) or G 1(dominant) generations. So far the total appearance
rate of developmentally abnormal fetus screened at G3
generation is about 5%.
(3) Analysis for Expression Profiles in the Mutant Tissues
Gene expression profiles of the abnormal tissues in
the mutant are analyzed by using Micro-Tissue cDNA
Subtraction Library and in situ hybridization with ahigh-throughput system. By combining these datawith genome analysis such as SSLP, RLGS or RDA(Representational Difference Analysis), we study themechanisms of which the mutagenized gene and resulted changes of gene cascade generate the mutant
phenotype. We applied these approaches to a mutant
strain BIOS with abnormal head morphology found at
EI0 and E13 G3 fetus , and analyzed its gene expression profiles as well as genome analysis. We got several genes expressed in the wild type head but not in
the mutant head. Using these cDNAs as probes, weinvestigate the causality of genetic defect and morphogenetic abnormality.
(4) Preservation and Functional Analysis Using EG
Cells
Primordial germ cells are isolated from the genitalridges in the fetus with mutant phenotype and cultured for establishing embryonic germ (EG) cells. Mutant genetic resource is cryopreserved in the form of
EG cells and utilized by the production of chimeric orclone mice. Function of lethal gene mutation in the live
animal can be examined by chimeric analysis. This approach is especially important in the screening at G 1
generations.

Department of Anatomy, Jikei Medical

References
1) A. Yoshiki et al.: RIKEN Accel. Prog. Rep. 33, 148(2000) .
2) W. R. Holley and A. Chatterjee: Rad. Res. 145, 188(1996).
3) B. Rydberg: Rad. Res. 145, 200 (1996).
4) Y. Hayashizaki et al.: Genetics 138, 1207 (1994).

RIKEN Accel. Prog. Rep . 34 (2001)

Mutation Induction by Heavy-Ion Irradiation of
gpt a Transgenic MiceT. Kurobe,*l N. Fukunishi, T. Nohmi,*2 M. Kusakabe, F. Hanaoka, and F. Yatagai
Transgenic mice can be used to detect mutations
accompanied by whole-body exposure to ionizing radiation. Recently, the tumor suppressor gene, p53, hascome to be regarded as a guardian of cells. Here, wereport on the progress in our current study to examine the involvement of p53 in mutations induced after
heavy-ion exposure, by using such transgenic mice system.
An outline of the mutation detection system isschematically illustrated in Fig. 1.1) After whole-body
irradiation with a 135 MeV lu C-ion beam, the genomic
DNA was isolated from various organs and the). DNA
was rescued in the form of a phage. Mutations in
the target gene of ). DNA was determined by both
gpt assay (6 TGR colonies) and deletion assay (spi (-)
plaques).
Enhancement of the gpt (-) mutant frequency was
not observed in liver after whole-body exposure to the
C-ion beam (10 Gy). Since point mutation seemed to
be in frequently induced, we focused on the spi (-)
assay in this study. An approximately 3-fold inductionin the frequency of the spi (-) mutant was observedin liver, kidney, and spleen after such C-ion exposure(data not shown).
Similar measurements were performed under different p53 backgrounds. In p53 (-1-) knockout transgenic mice, the spi (-) mutant frequency for DNA recovered from kidney was about 40% higher than thosefrom wild-type (p53 +1+) mice (Fig. 2). Similar en-~~_O,ga"-"- ,gpt Il mouseDNAr

6- TG colonies--_.COliE
Cr e+

EG 10 phagej$pi( - )PlaQUes.
E.coli P2 lysogen

Fig. 1. A scheme of mutation assay. ).. EG 10 phage was
rescued from genomic DNA of liver, kidney. The spi(-) mutation were detected by infecting E coli P2 lysogen, and spi (-) mutant frequency (MF) was calculatedby dividing the numbers of spi (-) plaques by that ofplaques of the total rescued phages. The gpt mutants,
which are resistant to 6-TG , were detected by infecting
E coli YG6020. And gpt (-) MF was calculated by
dividing the number of 6-TG and CM double resistantcolonies by that or CM single-resistant colonies.
*1*2

Advanced Research Institute for Science and Engineering,
Waseda University
Division of Genetics and Mutagenesis, National Institute of
Health Science

pS3(+/+)

pS3(+/-)

pS3(-I-)* P < 0.05 vs control;;P<O.05vs p53(+I+ )Fig. 2. Spi (-) mutant frequency (MF) for kidney recovered from C-ion irradiated gpt .6. mice. Open andclosed column represent the results from un- and 10 Gyirradiated mice, respectively. The symbol, (+ / + ),, (+ / -) and (- / - ), mean p53 wild type, hetero- andhomo-knockout mice, respectively.

10 53+1+ OCy I
4
12
H~
io

~ 1 3

red

am

Fig. 3. A deletion map of spi (-) mutants recovered fromkidney. A deletion part of the target region is expressed
as closed bar _ Numbers and arrows represent PCR mapping primers.

hancement by a defect of p53 was observed in spleen(50%), but not in liver (data not shown).
The spi ( - ) mutants recovered from kidney were analyzed by PCR amplification of the region of the target
gene, redl gam. The population of mutants, providing
PCR amplified products, did not differ greatly between
p53 (+1+) [32%] and p53 (-j-) [42%]. DNA sequencing analysis for PCR-amplified mutants demonstrated
frequent occurrences of the ± 1 bp frame shift and relatively short deletion (2- 488 bp) , but no significant difference in their occurrence was not found between the
two types of mice. For the remaining PCR unamplified
mutants , we carried out both PCR amplification andDNA sequencing over the wide range of phage DNA
beside the target region. As shown in Fig. 3, the mutants extending to primer 6, resulting in long deletion,
were more frequently recovered in p53 (- I -) than in
p53 (+1+).
These results suggest a possible involvement of p53
in the above mutation induction.
References
1) N. Nohmi et al.: Environ. Mol. Mutagen. 34, 9 (1999) .

175

RIKEN Accel. Prog. Rep. 34 (2001)

Cell-Cycle Arrest Delayed Following Heavy-Ion Exposure
S. Goto,*l S. Morimoto, T. Kurobe,*2 M. Izumi, N. FUkunishi, M. Watanabe,*l and F. Yatagai
Cellular responses after ionizing-radiation exposure
occur to protect cells from radiation damage. The purpose of this study is to assess the question, "Are there
different cellular responses between heavy ions and Xrays?" After X-ray irradiation, a variety of DNA damage is produced in cells. Each cell must possess somemechanisms responsible for damage repair, and cell-

cycle regulation is considered to be a mechanism tomake the repair more effective. Therefore, we examined cell-cycle progression after irradiation to elucidate
cellular responses. In fact, after 3 Gy X-ray irradiation,
human lymphoblastoid cells, TK6, showed an accumulation of cells at G2/M, the so-called G2/M arrest(Fig. 1 A). Compared to the X-ray case, cell exposure
C)

B)

A)

i X-ray4

Fe ion

4

~ 3
:;

"82
"0
a

t! 1

~
g.
.~ O'=-"o~--':-'-"""""7-'-~1::-'"2~7:16~--:2:o:-'O~24~

Time afterirradatim (b)1216Time afterirradatim (b)

20

24

12
16
T_afierirradalim(b)

20-

24

Fig. 1. TK6 cell-cycle progression after irradiation with (A) X-rays, (B) carbon ions (22 keY / /-lm), and(C) iron ions (1000 ke V / /-lm). Following the radiation exposure, cells were fixed with ice-cold methanol
at each postirradiation time and the nuclear region of cells was stained with propidium iodide (PI).
Cell-cycle distributions were analyzed by laser scanning cytometry (LSC). The population of cells ina particular phase is expressed as a relative percentage with respect to each phase of the unirradiatedsample.
A) Bromodeoxyuridine-:---~ Br(BrdU)

l. I

"OC~P

TK6

B)

~;'~\~~r:~Co~ ~ _.... ~~~WJVRXed.::>_t~,le~::' ~?olilcalionslained

~

&

~

~

~

~
,
01

y

PI
02

de'iion~sfamed nuclear region~

wllh ProPldl,m Iodide (PI)

value

,

0U 2

PI value(Nuclear value)

LSC

S

Fig. 2. (A) Chemical structure of bromodeoxyuridine(BrdU). (B) A principle for detection of the transfer
pattern of the incorporated BrdU. After adding BrdU
into the medium, cells incorporate it during DNA replication. These labeled cells were fixed with ice methanol,and stained with mouse monoclonal BrdU antibody andanti-mouse FITC. If cells incorporate BrdU, they canbe detected by their green fluorescence. Moreover, thenuclear region of cell is stained with propidium iodide(PI). Laser scanning cytometry (LSC) reveals the staining patterns of BrdU and PI, which reflects the DNA
replication frequency and cell-cycle distribution.
*1
*2

176

Department of Health Science, School of Pharmacological
Science , Nagasaki University
Faculty of Science and Engineering, Waseda University

to carbon ions (LET 22 Ke V / J-Lm) and iron ions (LET
1000 ke V / J-Lm) resulted in the delayed accumulation of
G2/M cells (Fig. 1 B, C). To determine whether this
delay is due to cell freezing in the S-phase, cells undergoing DNA replication in the S-phase were prelabeledwith bromodeoxyuridine (BrdU) before irradiation tofollow their cell-cycle progression (Fig. 2) . The transfer
pattern of cells with incorporated BrdU demonstrated
that the heavy-ion exposed cells remained in the Sphase longer (Fig. 3). In terms of cell-cycle progression, cellular responses are clearly different between
X-ray and heavy-ion exposure . These results suggestthat the repair for heavy-ion produced DNA damage isdifficult in the S-phase because the damage is different
from that induced by X-ray irradiation.

control

9 hours after irradiation
X-ray
C ion
Fe ionBrdU

PIFig. 3. The transfer pattern of prelabeled BrdU. Before
exposure, cells were prelabeled with BrdU for 15 min.
The labeled S-phase cells were followed for 9 h after irradiation with different types of radiation (see text).

RIKEN Accel. Prog. Rep. 34 (2001)

Cellular Responses after Low-Dose Exposure to Heavy Ionss. Morimoto, M. Izumi, N. Fukunishi, F. Hanaoka, and F. Yatagai
Bodily exposure to ionizing radiation is unlikely tooccur in day-to-day life. However, we cannot neglect
the risk of exposure to accelerated heavy ions in special
cases involving individuals who work nearby a nuclear
reactor, spend time in a space environment, etc. Lowdose effect studies seem to be very important not only
for radiation risk estimation but also to obtain a basic
understanding of radiation biological effects.
Our previous studies revealed several characteristics
of mutations in the human hypoxanthine phosphoribosyltranferase (hprt) gene after heavy-ion exposure. 1)
The induction pattern of signal-transduction proteins
as well as the cell-cycle progression after heavy-ion exposure was also shown to be different from those following X-rays.2) We recently examined the presenceof adaptive responses in the same cell line after preexposure (5 to 20 cGy) to C-ions (22 keY / J.lm) and Feions (1000 keY / j.Lm).3 ) A relatively high level inductionof the above proteins was observed in cell mass after
the pre-exposure; this did not, however, have a clear
influence on either the depression of the mutation or
on the recovery from lethality following the challenging
X-ray irradiation.
The above low-dose exposure is schematically illustrated in Fig. 1. In this study we assess the protein
induction in the individual cell instead of the massstate , because such an assay might reveal the cellular responses in an early stage following the heavy-ion
exposure. Human lymphoblastoid cell line TK6-E620C was irradiated by a low dose (10, 20, 50 cGy) of
C-ions or Fe-ions, and then incubated for 2 hours at
37°C to detect the induction of p53 protein by indirect
immunofluorescence staining (Fig. 2). The populationof p53:..induced cells was calculated by immunofluorescence staining (Fig. 3). In contrast with C-ions and
X-rays, a much lower population of p53-induced cells
10 cGyC-ions(22 keV/j.Jm):. . >: ·. ·.0··· ::0./:\.::~....

Fe-ions

20 cGy50 cGy200 cGy..: ·····Id·:···::·:O·:·....... .
:0 :'····: .. : : : : :.' : : .. :.

'. ',' .',

~.\.
'",

jUl ~ro-l~(1000 keV/j.Jm)~

UU?JU. Heavy ion

OCel!

Fig. 1. A schematic illustration of cells hit by primary accelerated C-ions (22 keY / }.Lm) and Fe-ions(1000 keY / }.Lm).

10cGy

o cGy

20 cGySOcGy

200 cGy

X-raysC-ion(22 keV/tJITl)

Fe-ion(1000 keV/lim)

Fig. 2. In situ indirect immunofluorescence detection of
p53 in TK6-E6-20C after X-rays, C-ions (22 keY / }.Lm),and Fe-ions (1000 keY / }.Lm) exposure. Cells were fixed
after 2 hour incubation (37°C), then attached to a coverslip, and stained with monoclonal antibody againstp53 (DO-I, Santa Cruz Biotechnology).

100~~~~'-~~~-'~~~~~~~-ro

8 0 .......................................1....................... .........:

60_____ X-rays............. - 0 - C"ions (22 keV/l-lm)----rr- Fe-ions (1000 keV/l-lm)

o

o

5 0

100

1 50

200

Dose [cGy]Fig. 3. Population of p53-induced cells after X-rays, Cions (22 keY / }.Lm) , and Fe-ions (1000 keY / }.Lm) exposure. About 100 cells were counted to calculate the percentage from the pictures, as shown in Fig. 2.
as observed in the case of Fe-ions. Immunofluorescenceanalysis revealed that the population of p53-induced
cells is proportional to the probability of the cell being
hit by a primary heavy ion. We plan to extend thisline of analysis using antibodies against other related
proteins to obtain a better understanding of cellularresponses in individual cells.
References
1) Y. Kagawa et al.: Mutagenesis, 14, 199 (1999).
2) A. Gordon et al.: RIKEN Accel. Prog. Rep. 33, 131(2000) .
3) S. Morimoto et al.: Adv. Space Res. in press (2000).

177

178

5. Instrumentation

RIKEN Accel. Prog. Rep. 34 (2001)

Production of Secondary Beam through Rigidity Selection
T. Yamaguchi, T. Zheng,*1 ,*2 A. Ozawa, 1. Tanihata, K. Morimoto, T. Suda, M. Chiba,*3 and K. Katori
For the multipurpose utilization of radioactive ion
beams, the EIC beam line has been rearranged to anintermediate-energy secondary beam line. The previous beam line 1} was used to study the nuclear highspin states, where the high-spin isomer beam was produced by the heavy-ion-induced fusion reaction and thebeam energy was low. On the basis of the old beamline, the present beam line can be used to transportintermediate-energy beams produced by the projectile
fragmentation method. Figure I shows the layout of
this beam line.
In order to obtain a well-separated secondary beam,
we combine magnetic rigidity analysis with spatial selection. Secondary beams can be produced by impinging primary beams on a production target. Byadjusting the magnetic field of the dipole, a beam with a certain magnetic rigidity can be selected. After passing
through the dipole magnet, the beam is dispersively
focused on the first focus point (FI), while the primary beam is stopped inside the chamber of the dipole
or in the baffle immediately after the dipole. Using the
4 directional slits (4D slits) located at FI, the beamof interest can be selected by spatial distribution. The
momentum acceptance of the beam line can also be defined by this slit. Finally, the selected beam is nearly
achromatically focused on the second focus point (F2).

The first-order transfer matrix elements calculatedby the code TRANSPORT 2) are shown in Fig. 2. Because of the small apertures and small focusing power

2
0
-2

C/)

C
Q)

-4

E
Q)

Q5

-6

x
.;::

EJ D D

Cti
E
....
Q)

0

01

D D

F1

02

03

F2

04

6

U5

(yj¢)

c:

ro

4

~
2
0
-2
0

2

4

6

8

Length (m)Fig. 2. First-order transfer matrix elements calculated by
the code TRANSPORT. 2 ) (xIB) and (YI4» are given in
m/rad, and (xI8) is given in cm/%.

Dipole magnet
Beam
fromRRC_J '1Profile monitor
Faraciaycap

o

-at-

PPAC-aTarget chamber

SI detector (><2)
inside1m

UJ@J

Fl chamber

Jm&de

PPAC

Fig. 1. Schematic view of the present EIC secondary-beam line. In the target chamber, three targets
and ZnS can be installed. The opening space of the x direction of baffle is fixed at ±18 mm, whichis the same as the acceptance of the beam line. 4D slits have two sets of movable slits for x (leftand right) and y (up and down) directions. In the Fl chamber one PPAC is installed, and in the F2chamber two PPACs and two Si detectors are installed for secondary beam diagnostics.
*1
*2
*3

Science University of TokyoP eking University, China
Tohoku University

179

Table 1. Basic characteristics of the present secondarybeam line.
Configuration
Angular acceptance
Momentum acceptanceMax. Bp
Deflection angle
Focus at F1
Focus at F2
Dispersion at F1
Magnification at F1
Magnification at F2
Path length

7

D-Q-Q-Q-Q
B: 9 mrad, ¢: 5 mrad

±4%
3.5Tm
20°
dispersive
nearly achromatic(xI8) = 0.5 cm/%(xix) = -1.3, (yly) = 2.1(xix) = 0.4, (yIY) = -0.8
4.2 m (target to F1)
8.4 m (target to F2)

6

N

5 ·

4

3 .

, -, '".

2~--~~-----L~--~~----~--~~

2.0

of Q1 and Q2 quadrupoles, the beam optics for they direction is designed to be point to parallel (fromtarget to F1), and parallel to point (from F1 to F2).
By doing so, a larger angular acceptance is obtained.
The basic characteristics of this beam line are listed inTable 1.
For particle identification, several detectors are installed. A parallel-plate avalanche counter, PPAC 3 )(charge division type, sensitive area 100 x 100 mm 2),
is placed at F1 to measure spatial distribution of thebeam. Two PPACs are placed at F2 to determine
beam trajectory. PPACs installed at F1 and F2 can bealso used as counters for a time-of-flight (TO F) measurement. Two Si detectors installed inside the F2chamber measure tlE. The magnetic field (B) of thedipole is monitored by a Hall probe. Using the Bp.6..E- TOF method, the secondary beam can be easily
identified.
In order to check the performance of this new beamline, we carried out a test experiment. A Be target was
bombarded with a 70-AMeV 15N 7 + beam to produce
the secondary beam. We were mainly interested in the
N = 8 isotones such as 14C, 13B, and 12Be. Using
the Bp-.6..E- TOF method, particle identification was
realized. Figure 3 shows a typical example of the results of 14C production, where Z was deduced fromthe energy deposit in Si detector, and AI Z was deduced from TOF between target (RF signal of ring

180

2.2

2.6

2.4

2.8

3.0

AIZ

Fig. 3. Result of production of 14C beam. The magnetic
field of the dipole was set higher than that of the centerof the momentum distribution of the 14C beam. The
x-axis shows AI Z and the y-axis shows Z of detectedparticles.

cyclotron) and F2 (timing signal from PPAC at F2).
In Fig. 3, 14C was clearly identified, and the other nuclei within the same B p region were also observed as
expected. In order to reduce scattered particles originating from the primary beam, the magnetic rigidityof the dipole was set higher than that of the centerof the momentum distribution of the 14C beam, which
was calculated by the code INTENSITy.4) However ,many scattered particles still entered the detector system . To minimize such an effect, detailed analysis andfurther improvements are now in progress.
References
1) T. Kishida et al.: RlKEN Accel. Prog. Rep. 28, 50(1995) and references therein.
2) K. L. Brown: Adv. Particle Phys. I , 71 (1983).
3) H. Kumagai and K. Yoshida: RlKEN Accel. Prog. Rep.
28, 127 (1995).
4) J. A. Winger et al.: Nucl. lnstrum. Methods Phys. Res.
B 70, 380 (1992).

RIKEN Accel. Prog. Rep. 34 (2001)

Development of Low Energy Polarized Radioactive
Isotope Beams
H. Miyoshi,*l K. Asahi, H. Ogawa,*l H. Deno, and T. Suzuki*2
A number of nuclear moments have been measured
at the RIKEN Ring Cyclotron during the last decade,by using spin-polarized beams from the fragmentation reaction combined with the nuclear magnetic resonance via change in the angular distribution of /3 rays(/3-NMR method). This approach, however, requires
several conditions to be fulfilled. One is to find a suitable host material in which spin-polarized nuclei can be
implanted, since the spin relaxation time is very sensitive to the chemical properties of an implanted atomand the host material. The size of the /3-ray asymmetry
parameter, which largely determines the performanceof the measurement, is another important factor.
To avoid the difficulties forecast in such requirements when the measurement is extend to the heavier
mass region, we attempt to develop a method which
involves a low-energy spin-polarized radioactive isotope (RI) beam, which we call the Atomic-Beam RI
Polarization method (ABRIP). The advantage of thismethod is that neither special host material nor a large/3-ray asymmetry is required, since the magnetic resonance is performed in-flight and the resonance is detected simply by counting the radiations of the transmitted RI.
In the following, a method to produce low-energy
spin-polarized RI beams is proposed. First, the RI
atoms are stopped in a noble gas in a cell. The temperature of the gas is kept as low as 80 K. Then, the RI
atoms are ejected together with the gas into vacuum
from the cell. A nozzle l ) is mounted on the exit of thecell so that the gas spouts out at forward angles. The
spread of the angles of the gas flow can be set within
3- 4 degrees, as reported in Ref. 1. A schematic viewof the setup is shown in Fig. 1.
A hexapole magnet is installed to converge the beamfrom the nozzle of the cell. The force on the atoms ina strong magnetic multipole field, B(r), is given as
F(r) = f.L\l B(r),(1)

where f.L is the atomic magnetic moment and B(r) thestrength of the field B(r). The field distribution B(r)within the magnet bore can be calculated using formulae derived by Halbach. 2 ) For a hexapole magnet
consisting of M wedge-shaped segments, one finds:*1*2

Tokyo Institute of Technology
Sony LSI Design Inc.

Fig. 1. Schematic view of the ABRIP device. The indicatedtrajectories for RI atoms are the results of simulation
when the RF field is applied.

25000
20000

W
(/)
~
co

15000

co

10000

~

foooQ..Q.O-eG'Q 'oo: 0

~

5000

O ....~I-I---'-----L-~-.L....---'---"-'-'-"-----'.---'---""-"-'"""

o

5

10

15

20

25

30

35

40

45

50

z (em)

Fig. 2. Comparison of B(r) field obtained from Eq. (2) inthe text (dots), with the simulated value from the code
OPERA 3) (dotted lines). The three hexapole magnets
are assumed to be 12 cm long each with 2 cm interval
spacing.

where ri and r 0 denote the inner and outer radii of themagnet , and Bo the residual field. In our calculation,
the hexapole magnet is assumed to consist of 24 segments of permanent magnets. The magnetic field at
the pole tip is about 1.5 T. The radius ri is varied overa region 0.5- 3cm while ro is fixed at 7.5cm. Comparison of the calculated hexapole B(r) with B(r) using
the simulation code OPERA3) is shown in Fig. 2. The
B(r) field evaluated from Eq. (2) is in good agreementwith the simulation result. We therefore employed theB(r) value from Eq. (2) to simulate the particle orbit
in the hexapole field. In Fig. 1, the simulated trajectories for atoms with spins parallel to the field (low-fieldseekers) are shown, where convergence of the beam isapparent. At the final stage, a quadrupole magnet isinstalled to obtain a polarized RI beam. By select-181

Table 1. Simulation results for the transmission and total
efficiency for various mass numbers of RI atoms. For
the definitions of the transmission and total efficiency,
see text.

A
20
30
40
50
60
70
80

Transmission (%)
RF-On
RF-Off
17.75
0.15
27.27
0.50
33.12
0.62
33.02
1.00
29.34
1.15
26.42
1.39
21.73
1.59

Total efficiency(RF-On)7.69x 10- 6
1.18x 10 51.43 x 10- 5
1.43 x 10- 5
1.27x 10- 5
1.14x 10- 5
9.42 x 10- 6

ing the beam direction, a high degree of polarization
is expected.
In the low-field region located between the hexapole
magnet and the quadrupole magnet, an RF field is applied in order to induce transitions between different
spin states. The entire setup is arranged so that when
the frequency of the RF field is off-resonance the detector located behind the quadrupole magnet counts no182

transmitted particles. When the resonance is met, thespin transition occurs and the deflection of the flightpaths due to the quadrupole field turns and results incounts at the detector. In Table 1 we list the simulatedtransitions and efficiencies of the apparatus. Here, the"transmission" is defined as the ratio of the number of
RI atoms reaching the detector to that of the atoms
released from the nozzle. The "total efficiency" is a
product of several factors: (transmission) x (detection
efficiency) x (RF transition efficiency) x (probabilityof RI atoms stopping within the gas cell).
In our simulations, the degree of polarization is evaluated as exceeding 99%. Thus, although the total efficiencies may not be very high, the resonance detection is expected to be carried out with very high Signal/Noise ratios , enabling the moments measurementsof nuclei in regions far from stability.
References
1) W. J. Hiller and W.-D. Schmidt-Ott: Nucl. Instrum.
Methods 139, 331 (1976).
2) K . Halbach: Nuel. Instrum. Methods 169, 1 (1980).
3) OPERA-2d and OPERA-3d/TOSCA , Vector Field,
Ltd., UK.

RIKEN Accel. Prog. Re p. 34 (2001)

Installation of Low-Energy RI Beam Separator CRIB
Y. Yanagisawa, S. Kubono,*l T. Teranishi,*l Y. Mizoi,*l S. Watanabe,*l M. Notani,*l S. Michimasa,*lK. Ue,*l Y. Ohshiro,*l N. Yamazaki,*l S. Shimoura,*l, S. Kato,*2 and M. Kase
Low-energy radioactive isotope beams of around
10 MeV lu provide great opportunities to investigate
nuclear properties as well as to study nuclear astrophysics. We have installed a low-energy radioisotope
separator, called CRIB, which is an inflight separator, in the E7 room. CRIB consists of the magnetic
spectrometer DUMASl) and a velocity selector (Wienfilter). This separator is installed as a part of the
CNS-RIKEN collaboration. The facility enables one
to obtain radioactive isotope beams of energies below
10 MeV per nucleon by using the primary beams fromthe AVF cyclotron.
The DUMAS is designed to be a doubly achromatic
spectrometer with an intermediate dispersive focus between the two dipoles. Figure 1 shows a schematic
view of the CRIB. Particles produced by nuclear reactions at the primary target, for example, (p, n) and(d, p) reactions, are collected and separated throughthe spectrometer, and focused downstream where asecondary target is placed for a radioactive beam ex-

F1

Q2

10 degE7 room

Fig. 1. Schematic view of CRIB.
*1

Center for Nuclear Study, University of Tokyo*2 Yamagata University

Table 1. Specifications of CRIB .
Maximum energy
Orbit radiusSpectrum range
Maximum solid angle
Deflection angle
Length of central orbit
1st focal plane
Size
Energy dispersion

Tilted angle
Energy resolution
2nd focal plane
Energy dispersion
Magnification

Emax= 110 Z2 / A MeV

p = 84-98 em±7.7% in momentum(±15% in energy)
6.fl max = 5.6 msr(75 mr (H) x 75 mr (V))
185deg
L = 7.80m (p = 90cm)
40 cm (H) x 8 em (V)
6.x · E/6.E= 700mm (p = 98cm)= 1015 mm (p = 84 cm)
Odeg
6.E / E = 1/350oMx = 1.5, My = 0.2

periment. The principle of isotope separation is basedon the magnetic rigidity analysis and the energy lossof particles. A degrader is placed on the intermediate
focus to generate energy loss. The basic specificationsof this magnetic system are listed in Table 1.
The spectrometer consists of five main magnets (QlD1-Q2-D2-Q3) and two small correction magnets (M1and M2), as shown in Fig. 1. All these magnets aremounted on a platform which can rotate from -5 deg.
to 60 deg. around the center of the FO scattering chamber. Particles produced at the target are analyzed withrespect to their momenta in the first half of the system
and are focused dispersively on the first focal plane F1.
The first section with the configuration of Q-M-D-Q
gives a dispersive focus at F1 and analyzes the magnetic rigidity of reaction products. The primary beam
will be stopped on the wall of a water-cooled aluminum
faraday cup inside the first dipole. The second section
with a configuration of D-M-Q compensates the dispersion of the first section and gives a doubly achromatic
focus at F2.
Development of the CRIB facility is in progress. The
velocity filter system after F2 focal plane will be installed soon in order to increase purity of the secondary
beams. The next plan for the CRIB facility is to installa gas target system 2) for the production of secondary
beams using fusion reactions.
References
1) T. Noro et al.: RCNP Ann. Rep. 1983, 173.
2) T. Kishida et al.: Nuel. Instrum. Methods Phys. Res. A
438, 70 (1999) .

183

RIKEN Accel. Prog. Rep . 34 (2001)

Installation of a Gas-Filled Recoil Separator (GARIS) at the RIKEN
Linear Accelerator Facility
K. Morita, M. Kase, Y. Yano, A. Yoneda, K. Morimoto, T. Suda, A. Yoshida, Y. 1. Zhao, K. Katori,and 1. Tanihata
This year, a gas-filled recoil separator (GARIS)l)
was installed in an experimental hall of the RIKEN
Linear Accelerator (RILAC) facility. The separator
was designed for fast (in-flight) and effective collectionof the nuclear reaction products separating them froman intense primary beam. The GARIS was originallyinstalled in an experimental hall (E1) of the RIKEN
Ring Cyclotron (RRC) facility and used mainly forsearching for new isotopes which were produced infusion-evaporation reactions. 2 - 4 )As part of an RI-Beam Factory (RIBF) project,5)the E1 experimental hall will be used for a beam transport line from the RRC to a new accelerator area. Thus
we need to relocate the entire separator setup from theE 1 experimental hall.
A new accelerator-decelerator system (CSM: charge
state multiplier) was installed immediately downstream of the existing RILAC also as part of the RIBF
project. The CSM consists of an accelerator section, acharge stripping section, and a decelerator section inthis order. With the accelerator section of the CSM we
obtain a beam with the maximum energy of 5.8A MeV,
while the highest beam energy available with the RILAC only is 4A MeV. This maximum beam energy
value, 5.8A MeV, is suitable for studying the nuclear
fusion-evaporation reaction. This is because, for almost all pairs of beam- and target-nucleus combinations, the energy is sufficiently high to overcome a
Coulomb barrier of an incident channel, but is not sohigh as to excite the fused nucleus excessively. Since
the high excitation energy of the compound (fused) nucleus leads the main decay channel to fission, the survival probability of the evaporation residues becomes
small.
Under these circumstances we decided to transfer
the GARIS from the E1 experimental hall at RRC toan experimental hall behind the accelerator section of
the CSM to continue experiments using the GARIS.
An advantage of this relocation is that we expectthat we will be able to obtain a more intense beamon target than we have with the RRC because we cangreatly reduce the beam path length by skipping the
RRC and its long beam line. The figure of merit isexpected to be about one order of magnitude in thecase of a Kr beam. One of the most interesting applications of the GARIS is the discovery of isotopesof new elements whose atomic number is greater than
113. These elements are the so-called superheavy elements (SHE). Because the production cross section ofsuch a reaction is estimated to be less than 1 picobarn

184(10- 36 cm 2 ), the figure of merit is important to thedesign of this kind of experiment. Here, we estimate
the counting rate of such an experiment in order todemonstrate how important the high beam intensity
is. We assume that the production cross section ((7) is
1 picobarn (10- 36 cm 2 ). Typical target thickness (T)is 200p,g/cm 2 (6 x 10 17 atom/cm 2 ), and typical beam
intensity (I) from the RRC is 1 particle-p,A (6 x 10 12
ion/s). Then, if we assume that the total detection
efficiency (E) is 0.5 we obtain a counting rate (Y/s) of
the event by multiplying these numbers , as
Y/s=Ex(7xTx!

)= 0.5 X 10- 36 x 6 X 10 17 X 6 X 10 12= 1.6 X 10- 6 /s (= 1/7.2 day).
This counting rate means that we expect an event ina little more than 1 week, on average. If we obtain ten
times higher intensity, we can expect an event every
17.4 hours, on avarage.
We can expect further profit. Now two accelerators,
the RILAC and an azimuthaly varying field (AVF) cyclotron, are used as injectors for the RRC. Three years
from now, the RRC will be operated mainly throughthe AVF cyclotron injection, then we will be able tooccupy the beam time of the RILAC operation mostly
for our experiments. Thus we can expect to have much
more beam time than we currently have at the RRC.
This situation will allow us to perform a systematic
study of the SHE region.
Along with this relocation, we have made some improvements to the GARIS. The original GARIS consisted of three magnets in a D1-Q1-Q2 configuration,
where D denotes the dipole magnet and Q denotes
the quadrupole magnet, as described in Ref. 1. The
distance between Q1 and Q2 was 330 mm. The distance has now been increased to 520 mm. When we
designed the Q-magnet, the effect of the large bore radius (150 mm) was not properly taken into account. As
a consequence, the focusing power of Q2 was lacking
at the highest Bp value of the D-magnet. By changing only the distance between Q1 and Q2, the focusing power is expected to recover without changing thepower supply to the Q-magnet.
Another improvement was made by installing a new
D-magnet (D2) between Q2 and the focal plane. In theexperiment, incident beams are stopped by a graphite
wall in the D1-magnet. A large number of lightcharged particles are emitted there. Although the Bp
values of these light-charged particles are far different
from the values of the reaction products of interest,because their source points are not as those of the reaction products, they reach the focal plane by passing
through the Q-magnets. These light-charged particles
come into the focal plane detectors, and create a main
background signal in our detection system. This additional D-magnet sweeps such light-charged particles
from the focal point. In this way we expect to realize a low background condition at the highest beam
intensity.
Testing experiments for measuring the characteristics of the new GARIS system are scheduled for early

2001.

References
1) K. Morita et al.: Nuel. Instrum. Methods Phys. Res. B
70, 220 (1992).
2) K. Morita et al.: Z. Phys. A 352, 7 (1995).
3) Y. H. Pu et al.: Z. Phys. A 357, 1 (1997).
4) Y. Tagaya et al.: Eur. Phys. J. A 5, 123 (1999).
5) Y. Yano et al.: Proc. 15th Int. Conf. on Cyclotrons andTheir Applications, Caen, France, (lOP, 1998), p.696.

185

RIKEN Accel. Prog. Rep. 34 (2001)

Absolute Calibration of Deuteron Beam Polarization at Intermediate
Energies via 12C(d, a)10B*(2+) Reaction
K. Suda,*1 H. Okamura,*1 T. Uesaka,*1 J. Nishikawa,*1 H. Sakai,*2 A. Tamii,*2 K. Sekiguchi,*2 K. Yako,*2
S. Sakoda,*2 H. Kato,*2 M. Hatano,*2 Y. Maeda,*2 N. Sakamoto, Y. Satou, and T. Ohnishi
At RIKEN Accelerator Research Facility (RARF),
we are studying nuclear reactions and spin structuresof the nucleus using polarized deuteron beam at intermediate energies. 1) Among these studies, the oneon the three-nucleon forces (3NF) draws considerable
interest. 2) In such studies, highly precise data are required to be compared with rigorous calculations. Accordingly, the accuracy of beam polarization also becomes crucial. The polarization is measured using thed-p elastic scattering as polarimetry at RARF. The analyzing powers for the reaction were calibrated against
the polarization measured by the 12 C (d, p) 13 C reaction
or 3He(d, p)4He reaction at the exit of the injector AVF
cyclotron. 3,4) However, systematic uncertainty arises
from the fact that the beam polarization and the analyzing powers for the d-p elastic scattering cannot bemeasured simultaneously. Moreover, systematic uncertainties of the analyzing powers for the two reference
reactions mentioned above are already significant inamount. Thus, we proposed to use the 12C(d, a)10B
reaction at 0° as a new polarization standard for the
deuteron beam at intermediate energies. 5 ) In Ref. 5,
we reported on the calibration of the analyzing powers
for the d-p elastic scattering using the (d, a) reactionat Ed = 270 MeV. As we reported, the statistical accuracy of the beam polarization measured using the(d , a) reaction was insufficient because the beam intensity was limited due to a high level of background
events. Thus, we performed calibration again with reduced background events at the same deuteron energy.
The amount of shield at the back of the beam stopper is increased, because particles from the stopper
are thought to be a major source of background events
at 0° measurement. The result is shown in Fig. 1. An
agreement between the present results and the datafrom Ref. 3 is fairly good. We also carried out thecalibration at Ed = 140 MeV. The result agrees withthe data from Ref. 4. These results indicate that thismethod of the calibraion using the (d, a) reaction is

*1

*2

186

Department of Physics, Saitama University
Departme nt of Physics , University of Tokyo

Ed. = 140MeV

Ed. =270MeV

0.6

Ayy

++

•

0.6

+

Ayy

;.•

0.4

¢

0.2

0.4

••

•

..,~

0.0
-0.2
0.0

•

-0.4

•

-0.2

A%%

• ••••••

••

-0.4

••

••

•
•
••

-0.6
60

80 100 120 140

8 c.m .(deg)60

80 100 120 140

8 c .m .(deg)Fig. 1. Analyzing powers for the d-p elastic scattering at
E d = 270 and 140 MeV. The present results are indicated by open squares in each panel. In the left panel,the data indicated by the closed squares are taken from
Ref. 3 and those indicated by circles are from Ref. 2.
In the right panel, diamonds represent the data takenfrom Ref. 6. The errors are statistical ones only.

useful at intermediate energies.
References
1) For example, H. Okamura et al.: Phys. Lett. B 345, 1(1995).
2) H. Sakai et al.: Phys. Rev. Lett. 84, 5288 (2000) .
3) N. Sakamoto et al.: Phys. Lett. B 367, 60 (1996).
4) T. Uesaka et al.: RIKEN Accel. Prog. Rep, 33 , 153(2000).
5) K. Suda et al.: RIKEN Accel. Prog. Rep. 33, 154(2000).
6) K. Sekiguchi et al.: RIKEN Accel. Prog. Rep . 34, 50(2001).

RIKEN Accel. Prog. Rep. 34 (2001)

The Design of a Polarimeter for a Spin-Polarized Positron BeamJ. H. Kim, F. Saito, N. Suzuki, L. Wei, Y. Nagashima, T. Kurihara, A. Goto, Y. Itoh, and T. Hyodo

A new positron polarimeter has been designed andits performance is simulated using a charged-particle
trajectory program. The results of the ray tracingare presented along with the details of the design
parameters and pr0jected system performance. The
positron polarimeter will be used in conjunction with
an electrostatic system in which 18F will be generated
as a polarized positron source using azimuthal varying field (AVF) cyclotron at RIKEN (The Institute ofPhysical and Chemical Research). The polarizationof the slow positrons will be measured by an orthopositronium quenching method with incident energies
of 0.1 to 30 keY in the presence of magnetic fields (upto 12 kGauss). The design of the polarimeter enables
the effective transmission of positrons to the sample byavoiding the reft.ection of the positrons using electrostatic lenses, which do not change the spin of positrons.
For the polarimeter shown in Fig. 1, slow positrons
are accelerated (0.1- 30 ke V) by a linear-type accelerator (1) and transported to a sample (2) through anelectromagnet (5). A set of lenses (3) with a 20 mm
inner diameter is used to focus the positrons onto thesample through a hole in the electromagnet pole pieces,producing a magnetic field. The beam profiles shownin Fig. 1 using the lenses to focus (a) and without using
the lenses (b) at the incident energy of 4 ke V, indicatethat the beam diameter at the sample can be reduced
from 11 mm to 2 mm. In Fig. 2, the beam diameter(open squares) becomes larger thus the positrons will
miss the sample when the beam energy is lower than
4 ke V . Using the lenses, the beam diameter (closed circles) is simulated to be 2- 6 mm in the range of beamenergies from 0.1 to 30 keY.
The reft.ection of the positrons due to the mirror effect is simulated as a function of the beam energies(0.1- 30 ke V) and magnetic fields (0- 12 kGauss) . Whenthe small lenses are not used, the reft.ection of thepositrons occurs at beam energies of less than 5 keY,even under weak magnetic fields (left side of the dotted line in Fig. 3). Focusing the positrons, as indicatedby the solid line, can reduce the mirror effect (shadedarea).
A ray tracing analysis indicates that this design iscapable of effectively transmitting positrons at beamenergies varying from 0.1 to 30 ke V within the beam
diameter of 2- 6 mm. However, the observed reft.ectionof the positrons (lower than 2 ke V) at 12 kGauss indicated that further refinement of beam design is needed
to produce a better positron polarimeter.

10 ,--- - - - - - -- - -- - - - ,Ii

111------~) 1:1:1-------

•,

,-..8

4

El

'!7
'"'
~
ecu 6

,

without focus

\

'-I

~

.. .

:s
El 5
=
~

=4
3

2

L-_~_~

o

5

__

10

~_~_~_~

15

20

25

30

Beam Energy(keV)

Fig. 2. The beam diameter at the sample as a function ofbeam energies. The open squares represent the diameter without focusing while the closed circles represent
the diameter with focusing.

12-=--+- with focusing

10

~
~

~

1
(a)
II1 ______________ 3

I pole gap = 34mml

9

• [J.

8

~ 6

without
focusing'-'

P

Fig. 1. Ray tracing simulations (with a charged-particle
trajectory program) of the polarimeter.

"0
~

'-=

4

=2
I

N o reflection

~

:
0

0

0

5

10

15

20

25

30

Beam Energy (keV)
F ig. 3. Magnetic field dependence of the beam reflection
as a function of beam energies.

187

RIKEN Accel. Prog. Rep. 34 (2001)

Development of Rotating Target for Big-RIPS in RIBF
A. Yoshida, K. Morimoto, A. Ozawa, M. Fujimaki, Y. Takahashi, and 1. Tanihata
A rotating target system for the projectile fragment
separator (Big-RIPS) in the RI-Beam Factory (RIBF)
has been developed. The assumed maximum heat loss
in the target material (beryllium or carbon) is for thecase of a 238U primary beam at 400 A MeV, 1 pp,Afrom the Super-conducting Ring Cyclotron (SRC). The
stopping range of the beam in the target material is
R = 18 mm and the optimum target thickness for producing the most intense secondary beams is approximately d = 6 mm (d/ R = 0.3) where the beam penetrates the target. Under this condition, it is expectedthat 20 k W heat loss occurs in a 1 mm-diameter beam
spot size. In order to avoid melting the target, the rotating target method is useful. A prototype was constructed and tested with the maximum intense heavyion beam from the present RIKEN Ring Cyclotron(RRC).
The maximum intense beam 40 Ar 9 + at 24 A Me V,
1.9 pp,A was bombarded on a carbon disk with a beam
spot size approximately 3 mm in diameter; the size wasdetermined using a ZnS foil. The range of the beam
is a depth of 0.5 mm and the thickness of the target
disk was 2 mm, thus the beam stops inside the target and releases its full energy of 1.8 kW in a narrow
Bragg peak region. The calculated heat density at
this peak region is approximately 690 W /0.12 mm =5.7 kW /mm, which is almost the same condition as theassumed maximum heat loss for the case of the 238U
beam mentioned above, 20 kW /5 mm = 4 kW /mm, if
the beam spot size is comparable. The carbon disk,
260 mm in diameter and 1.8 g/ cm 3 in density, wastightly fixed by screws on the water- cooled aluminum
plate and was rotated in the vacuum chamber (Fig. 1).
The temperature of the beam spot was measured by
Spot(~:~:~I""

~

.1-Ii

Beam

r'': :. :-.

Co oling Phte
(AU

I ..

Target"1:

Rotat>ng ' :Ferromatic
Feedtl)rough
;;:

.:-

<f/ P~:lt~

~.

t

0

I ....
l ..nt , ....

~!
~

Fix~ng::: :>;: :;::::1~~::o'~;1
unit size [ ... 1

1< : :

J~·: ~·~\.·.~_I;~ 2

Fig. 1. Cross-sectional view of the rotating target plate(left) and image of the beam spot (right).

188

1.8kw 10rpm

1 .8kw 1OOrpm

200

40tl

600

800

Fig. 2. Contour plots of the temperature distribution near
the beam spot with the maximum beam intensity of
1.8kWat 10rpm (up) and 100 rpm (down) corresponding to 126 and 1256 mmls in tangential speed, respectively.

an infrared radiation thermoviewer (TVS-2200, Avionics Japan) which has an InSb detector sensitive to 35.4 p,m infrared radiation. A BaF 2 glass window wasused to allow infrared radiation to penetrate from thevacuum chamber. The emissivity at the surface of the
carbon target and the BaF 2 window was calibrated using a thermocouple device and found to be 0.84. A typical temperature distribution of the beam spot is shownin Fig. 2. The position resolution of the thermoviewer
is approximately 0.6 mm/pixel, due to the size of its
digital image of 256 x 100 pixels. Each pixel has 256
levels of temperature information; its maximum range
is -40- 2000°C and its minimum resolution is O.l°C.
The refresh rate of one image is 30 flames/sec which is
sufficiently fast to achieve the position resolution mentioned above, even at the highest rotation speed of thetarget disk, 150 rpm.
A series of measurements varying the rotation speed
from 10 to 150 rpm and the beam heat loss from 0.2
to 1.8 kW was performed. A saturation effect was observed for the plot (Fig. 3 (a)) of rotation speed vsbeam spot temperature under the same heat loss condition, although the target volume in the tangential
direction increased linearly with the rotation speed.
This may be because the thermal diffusion coefficientis less than the rotation speed. A mostly linear correlation is observed between the heat loss dE vs the beam
spot temperature up to 1.8 kW heat loss, as shown in
Fig. 3 (b).
When we changed the flow rate of the cooling wa-

Beam Spot
Temperature

Beam Spot
Temperature
900
800
700
600

2

~ 500

Q)

~ 400 .

I-<

IV

E-<

400

300

'\

....

, ' ~:-+~~~~'-'"~....'...... ......_ ••O~
O ~~~6~
O ~9U
O ~1~20~~150

200
100

0.0

0.5

1.0

(a)

1.5
dE

Rot [rpm]

2.0

[kwj

(b)

Fig. 3. Maximum temperature of the beam spot was measured whilevarying rotation speed and heat loss in the target.
ter at 25°C from 5 to 10 liters/min under the beamheat loss condition of 1.S k W, we did not observe a
clear decrease in temperature at the beam spot, but
an increase in temperature at the outlet of the coolingwater from dT = 1.5°C to 2.SoC was observed. This
indicates that the cooling water carried away the heatfrom 9S0 W to 1050 W, corresponds to approximately
56% of the total energy released. Calculated thermalradiation at the beam spot temperature of SOO°C is
sufficiently small at approximately 3 W / em 2 . This indicates that there may be other paths of heat consumption in the target chamber which we have not yet
located.
When we stopped the rotation, the beam immediately shot through the target and made a small holeFig. 4. Holes in the carbon disk target caused by the beam when therotation stopped. Also, it cracked
due to a difference in thermal expansion.

(Fig. 4). The size of the hole was 0.7 x 1.2 mm, whichindicates a smaller beam spot than that measured by
the ZnS foil.
We need to develop a simulation program which can
explain our data so that we can predict the temperature under the 20 kW heat loss condition which can notpresently be reached in the RIKEN accelerator facility.
We have installed another rotating target system in thepresent RIPS facility and we continue to measure thedata for higher beam energies rv 100 A Me V and with asmall beam spot size of 1 mm in diameter.

189

RIKEN Accel. Prog. Rep. 34 (2001)

Development of Ferromagnetic Targets for Radioactive-Isotope
Beams and a Detector System for Transient
Magnetic Field Experiments
H. Veno, W. Sato, H. Ogawa,*l N. Imai,*2 K. Yoneda, A. Yoshimi, Y. Kobayashi,
D. Kameda,* l H. Miyoshi,*l K. Sakai,*l H. Watanabe, and K. Asahi
It is known experimentally that moving ions experience an effective magnetic field as strong as several kT while slowing down in polarized ferromagnetic
targets. 1 ) This magnetic field, the so-called transientfield, has been applied to the measurement of g- factors
for short-lived nuclear excited states. In the present
research, ferromagnetic targets for RI beams and a detector system for transient magnetic field experiments
have been developed in order to measure the g- factorsof short-lived (T rv ps) excited states for unstable nuclei.
Two types of materials, Fe and Cd, are prepared
as targets. An adequate degree of magnetizationis achieved by the following method. Iron foils arecleaned and rolled to the required thickness of rv
10 mg/ cm 2. The foils are first heated to rv 800 K in acolts tube furnace evacuated to a pressure of < 1 x 10- 6
Torr, then hydrogen is leaked into the furnace to apressure of 1 atm, and the temperature is increased
to rv 1200 K for one hour. Another method of annealing is employed for the preparation of gadolinium(Cd) foils , since Cd is known as an effective hydrogengetter. After being placed in the colts tube furnace ,2 thick Cd foils are heated to 11 00 K underrv 10 mg/ cm
a pressure of 1 x 10- 6 Torr for 10 minutes. The heating
power is then reduced slowly and the foils are cooled
to room temperature. Although magnetic anisotropyof hexagonal Cd shows a strong temperature dependence of the angle between the easy direction of magnetization and the crystallographic c-axis, it was reported that well-annealed polycrystalline foils show almost the same magnetization compared to the single
crystal. 2)
Figure 1 shows the schematic layout of the detector system. The multilayered target consists of
100-mg/cm2-thick Pb and the above-described wellannealed Cd foil facing each other and placed in a vacuum chamber. In order to obtain high magnetizationof the Cd foil an external magnetic field of B ext = 0.3 T
is applied perpendicular to the beam axis using a couple of coils placed outside the chamber. The multilayered target is supported with a Cu cold finger connected to a cold head of a cryostat which is cooled toliquid-nitrogen temperature also for the high magnetization.

*1

*2

190

Tokyo Institute of Technology
University of Tokyo

Plastic Scintillator(1.2m x 16)

Fig. 1. Schematic layout of the detector system for transient field experiments. For details , see text.

The , rays emitted from the excited RI-beam particles are measured using four 5.5" x 5.5" NaI(Tl) scintillators in coincidence with scattered RI-beam particles
detected with 16 f = 1.2-m-long plastic scintillators
which are mounted cylindrically with 7.5 em distancefrom the beam axis , as shown in Fig. 1. Thus scattering angles 5° < BLab < 165° and -80° < <PLab < 80°
and 100° < <PLab < 170° are covered. The four N aI
detectors are placed at angles BLab rv ±45° and ±120°
relative to the beam axis for measurements of the angular correlation and precession in the transient field.
The angles of the, detectors can be changed to givethe maximum slopes of measured particle-,-angularcorrelations depending on the nuclear alignment of theexcited state. Considering the limited energy resolution of the NaI(TI) scintillators, a Ce detector is also
used to locate contaminant lines in the photo-peak region of the focusing , transition as well as those fed
from higher excited states.
The first experiment using a RI beam is under preparation.
References
1) R. R. Borchers, B. Herskind, J. D. Bronson, L.
Grondzins, R. Kalish, and D. E. Murniek: Phys. Rev.
Lett. 20, 424 (1968).
2) O. Hausser, H. R. Andrews , D. Ward , N. Rud, P. Taras,
R. Nicole, J. Keinonen , P. Skensved, and C. V. Stager:
Nuel. Phys. A 406, 339 (1983).

RIKEN Accel. Prog. Rep. 34 (2001)

A Windowless Solid Hydrogen Target
S. Ishimoto,*l T. Kobayashi,*2 K. Morimoto,*l I. Nomura,*3
S. Suzuki,*l Y. Takahashi,*4 I. Tanihata, and T. Tsuru*l
A window less solid hydrogen target has been successfully developed l ) for RI-beam-induced nuclear reactions at the RIKEN RI Beam Facility currently under construction. 2) Increasing interest in heavy ion reactions requires a thin and flat solid hydrogen target
without any extra materials in the path of the particles. The target is a bare disk of solid hydrogen of
diameter 25 mm and thickness 5 mm (40 mg/ cm 2) heldin vacuum at low temperature. Hydrogen crystal isgrown either directly from normal hydrogen gas 3) orfrom its melt in a cell bored in a 10-mm-thick pure copper block which is cooled by liquid helium as shown in
Fig. 1. The two sidewalls of the cell were Teflon-coatedstainless-steel flanges, which were tightly pressed tothe cell plate by stainless-steel bellows. The bellows
were driven by helium gas introduced into them andwere precisely controlled by the gas pressure. A 0.8mm-thick indium gasket was used as a vacuum-tightseal. We employed a pair of step-type flanges when wechanged the target thickness.
We found that the following conditions are essential
to obtain a uniform crystal of hydrogen. The precooled
gas must be introduced at the top of the cell througha vacuum-insulated tube. By these precautions we areable to satisfy the two requirements; keeping the gas
inlet free in order to push out the void in the final
stage of solidification and producing a gentle upward
temperature gradient inside the cell which suppreses
the fluid dynamical instabilities in solidification fromthe melt. It is also important to establish a uniform
temperature over the surrounding wall of the cell except for the open end of the inlet tube, which ensuresuniform growth of the crystal on the wall as well as
preventing fluid dynamical instabilities. Precooling ofincoming gas to liquid nitrogen temperature is proved
to be pertinent. The vacuum sleeve inside the copper
plate keeps the inlet gas at an appropriate constanttemperature, which ensures the stable conditions forcrystal growth.
Flat hydrogen crystal with high quality has beenobtained reproducibly. After completing solidification,
the sidewalls of the cell, which are in the path of theparticles, are removed in the target cryostat and the
crystal is self-supported inside the cell. Thus, there is
no extra material in the path near the target. We haveobtained a uniform and transparent crystal of normalhydrogen of 25 mm diameter and of either 5 mm or
10 mm thickness.
*1
*2

*3
*4

High Energy Accelerator Research Organization
Faculty of Science, Tohoku University
National Institute for Fusion Science
Research Center for Nuclear Physics, Osaka University

LIQUID He BATH

1

H2 GASBELLOWS( He GAS CONTROLLED ) LINEAR MOTOR
STEP-TYPE FLANGESFOR t=5mm TARGET

Fig. 1. Assembly of the Teflon-coated flanges and bellows
for the sidewalls of the target cell, and a pair of steptype flanges for a 5-mm-thick target.

Figure 2 shows a photograph of the windowless solidhydrogen target of 5 mm thickness. A bare hydrogen crystal is self-supported inside the cell, i. e. , inside
the copper frame. The crystal is transparent and novisible defects are present. Holding the target at a
low temperature prevents the sublimation of hydrogenmolecules. At approximately 4.2 K , the sublimation
rate agrees with the value calculated from the vapor
pressure at thermal equilibrium. 4) The loss is negligible
when the target is held below 3 K. The method of crystal growth will be extended to the hydrogen isotopes,
HD, D 2, T2 and possibly to other cryogenic gases suchas nitrogen, argon, neon and xenon. The techniquesdeveloped here may be applied to various experimental studies in other fields involving neutron scattering, nuclear fusion, optical spectroscopy and solid statephysics.

191

References
1) S. lshimoto, T. Kobayashi, K. Morimoto, 1. Nomura,
S. Suzuki, Y. Takahashi, 1. Tanihata, and T. Tsuru:
RIKEN-AF-NP-348, KEK Preprint 2000-23 H, to be
published in Nucl. lnstrum. Methods Phys. Res.
2) 1. Tanihata: Nucl. Phys. A 588, 253c (1995).
3) T. Momose, M. Miki, M. Uchida, T. Shimidzu, 1.
Yoshizawa, and T. Shida: J. Chern. Phys. 103 , 1400
(1995).
4) P. C. Souers: Hydrogen Properties for Fusion Energy,(University of California Press, Berkeley, California,
1986).

Fig. 2. Bare crystal being held inside the target cell: thewindowless solid hydrogen target of 5 mm thickness.

192

RIKEN Accel. Prog. Rep. 34 (2001)

Construction of Liquid Helium Target
H. Akiyoshi, T. Minemura,*l M. Kunibu,*l and S. Shimoura*2
A helium target system was constructed for a radioactive nuclei induced (a,a') reaction experiment.
To overcome the low intensity of the radioactive nucleus beam, helium is liquefied. The liquid helium
target system worked well in a series of experiments
performed in October of this year.
Numerous cryotargets of 4 He have been built in thepast to be used in nuclear physics as well as in otherfields. In this report we describe the design chosen
for the radioactive nuclei induced (a,a') reactions. To
detect the T rays emitted after bombardment of radioactive nuclei from the RIKEN projectile-fragment
separator, RIPS, the target is surrounded by N aI scintillators. The amount of material in the path of ejected
T rays should be minimized in order to reduce the absorption of T rays, while the liquid helium target must
be kept at cryogenic temperature, which requires material for cooling and heat shielding. The target cell isisolated in vacuum, which requires additional material.
In order to minimize the dead solid angle combining
with the existing NaI array system, free space for thetarget is limited. To use the beam time effectively, thehelium target should remain in place for more than two
weeks without supplying liquid helium. Consequently,
we adopted a liquid helium target liquefied by a small
refrigerator.
Figure 1 shows a schematic diagram of the liquid helium target system. All the cryogenic-temperature sections are placed in a cylindrical vacuum chamber madeFig. 1. Schematic diagram of liquid helium target system.
Meanings of letters A-M are described in the text.

*1*2of thin aluminum (K) . A target cell (H) is cooled down
to approximately 3 K by the second stage of a GiffordMcMahon cycle refrigerator (N) through a connecting
component made of copper. The target cell, the connecting part and the second stage of the refrigerator
are surrounded by a heat shield (I) attached to the firststage of the refrigerator in order not to receive radiantheat from room temperature parts. A line of pipe (G)wraps around the connecting part, and is lead outsideof the vacuum chamber coiling around the refrigerator
cylinder. The pipe and the connecting part constitutea heat exchanger (J). Helium is liquefied at the heatexchanger and accumulates in the target cell. Throughthe pipe, helium gas from a gas cylinder (A) is introduced. The pressure of the helium gas is controlled bya precision pressure regulator (B). The gas pressure in
the helium supply pipe is measured by a manometer(C). The flow through the thin pipe causes a pressure
difference between the supplying part and the target
cell. Therefore, another manometer is used to measure the internal pressure of the target cell througha short-cutting pipe (F) connected to the target cell.
The valve E is normally closed. Relief valves are put
on both pipes in case of overpressure. Mass flow meters measure the supplied and released gas flow . We
can determine the state of liquefying by monitoring theflow rate. Temperatures of the target cell, the heat exchanger, the heat shield, the gas line near 300 K, andthe room temperature are measured by silicon diodethermometers. The output voltage of the thermometers, the manometers and the mass flow meters are
digitized by a digital multimeter (L), and acquired by
a computer (M).
The target cell is made of aluminum in order to reduce the absorption of Trays. Havar foils of 6p,mthickness are glued on the cylindrical target cell using
Stycast 1266 forming the entrance and exit windows
24 mm in diameter . The windows exhibit high stability and vacuum tightness, but the radioactive nucleus
beam may pass through it without large energy losses.
The thickness of the target is easily changeable arounda few hundreds mg/ cm 2. The heat shield is also madeof aluminum to reduce T ray absorption. Two holes
in the heat shield 30 mm in diameter allowing the entrance and exit of the radioactive nucleus beam arecovered with aluminized Mylar films so as to shield
the target from the room temperature parts.

Department of Physics, Rikkyo University
Center for Nuclear Study, University of Tokyo

193

RIKEN Accel. Prog. Rep. 34 (2001)

Construction of a Polarized Proton Target Using a Single Crystalof Aromatic Molecules
T. Wakui, M. Hatano,* l H. Sakai,* l T. Uesaka,*2 and A. Tamii*l
We have designed and constructed a proton polarizing system in order to develop a polarized proton solid
target applicable to experiments using a radioactive
isotope beam. The goal of this study is to attain apolarization of more than 50% in a target sample witha diameter of 20 mm and a length of 5 mm. The target will be used to investigate the structure of unstable nuclei through an experiment involving an inverse
kinematics. In such an experiment, a proton target
which can be polarized in low magnetic fields (1003000 Gauss) at high temperatures (77- 300 K) is desirable because it is necessary to detect low momentum
recoiled protons at a large detection solid angle.
Protons in a single crystal of aromatic molecules canbe polarized under such conditions by a method calledmicrowave-induced optical nuclear polarization. 1) In
this method, guest aromatic molecules doped in the
single crystal are optically pumped to the lowest triplet
state by laser irradiation. Populations of sublevels in
the triplet state are different from each other due tothe angular momentum selection rule. Then , the population difference is transferred to proton polarization
by means of the integrated solid effect (ISE) , a kind of
dynamic nuclear polarization method.2 '~he polarization procedure is described in a previous report. 4 )We use naphthalene and p-terphenyl molecules as ahost material and pentacene as a guest material. The
crystallization procedure is described in Ref. 5.
After crystallization, a section is cut from the crystal
and placed in the polarizing system shown in Fig. 1.
The system consists of a C-type magnet, a laser system
for the optical pumping, a microwave system for the
ISE and an nuclear magnetic resonance (NMR) system
for measuring the proton polarization.
The magnetic field produced by the C-type magnet
is about 3 kGauss. The magnetic field inhomogeneityof 10- 3 over the target size is required for obtaining
a proton polarization of more than 50%. We designed
a magnet which satisfies this condition. The diameterof the coil is 150 mm and the gap between the polesis 60 mm. The magnetic field inhomogeneity measured
using a NMR teslameter at a field of about 3 kGauss is
3.5 x 10- 4 over the target size. The field homogeneity
is sufficient for polarizing protons.
We use an Ar-ion laser for the optical pumping. The
wavelength of the main mode in the laser, 514 nm, corresponds to the energy of transition to the third excited
singlet state in pentacene. To obtain a high population difference in the lowest triplet state, a pulsed laser
*1

*2

194

University of Tokyo
Saitama University

ChtllP}~::rZt)~~~ILiaSierfsy_st_em~1·e..~,""=""--"-"='1 Ar-ion laser (A. =514 nm,CW)

oscillator

Digital oscilloscope-~
Voltage-to-current Function generator
converter

INMR system I

Fig. 1. Experimental setup for proton polarizing system.
The system consists of a magnet , a laser system for
optical pumping, a microwave system for the ISE and
ESR measurements and an NMR system for measuring
the proton polarization.

beam is required because the lifetime of the most populated level in the triplet state is shorter than thatof other levels. For pulsing the laser beam, we usean optical chopper. The pulse width and the repetition rate are 20 J.LS and 1 kHz, respectively. The pulsed
laser beam is injected from behind the magnet to thetarget sample.
Since the frequency of the electron spin resonance(ESR) in pentacene is about 9.1 GHz under a magnetic field of 3 kGauss, the target sample is placed ina cylindrical microwave cavity. It is necessary thatthe cavity enables the laser irradiation for the opticalpumping, the magnetic field sweep for the ISE and theapplication of the RF field for the NMR, without impairing the quality factor. Moreover, the target sample
has to be kept at a temperature ranging from 77 K toroom temperature. We introduced sets of internal RF
and field modulation coils into TEoll cylindrical cavity; both were placed parallel to the cylinder axis in
the cavity, as shown in Fig. 2. Both coils are configured in a two-loop arrangement and are made fromfour Cu rods with a 2-mm diameter. The quality factor of the cavity is not impaired by the coils as longas the rods are kept parallel to the cylinder axis, andis about 4000 at room temperature. The coil configuration also permits the laser irradiation of the target
sample. A quartz tube, on which the target sample ismounted, is placed into a double quartz tube placed
among the coil rods along the cylinder axis. Cooled
N2 gas is introduced into the inner quartz tube when

>'

0

o

- 50

§

5

~ - 100- 150~~~~5~0~~~10~0~~~1~50~~

Relative magnetic field [Gauss]:!=~==~Ied N2 Gas

Fig. 3. The ESR spectrum of DPPH (2,2-diphenyl-1picrylhydrazyl) of about 50 J-tg in a magnetic field of
about 3 kGauss. DPPH is used as a standard sample
for optimizing the microwave system.

.1
Fig. 2. Schematic view of the TEoll cylindrical cavity. The
cavity contains sets of internal RF and field modulationcoils. The quality factor of the cavity is about 4000 atroom temperature.

protons are polarized below room temperature.
The schematic diagram of the microwave system isshown in Fig. 1. A microwave from a Gunn oscillator
is pulsed and amplified by a microwave amplifier. Its
maximum output power is 20 Wand the pulse duration
is 10 J-lS. A circulator attached to the output stage ofthe amplifier protects it against damage due to unexpected reflection of microwaves. Pulsed microwaves are
split with a magic tee, one arm of which is connectedto the cylindrical cavity. The other arm (balance arm)
is equipped with a phase shifter and a matched load.
The impedance of the cavity is matched with that ofwaveguides by changing the diameter of the iris, a holebetween the cavity and a waveguide.
During the pulsed microwave irradiation, the magnetic field is swept through the entire width of an ESR
spectrum, whose width is about 30 Gauss, in order toperform the ISE. The field sweep is done by applying
a triangular wave of about 50 A p _ p to the field modulation coil in the cavity. The current is produced by
a voltage-to-current conversion circuit using a highpower operational amplifier.
We observed the ESR spectrum of a sample with acw microwave so as to align the long molecular axis
parallel to the direction of the magnetic field, because
the population difference is maximum in this direction.
The cw microwave is amplified by the amplifier which
is used for the ISE. The maximum output power forthe cw microwave is 100 m W. In the measurement,
reflected microwaves from the cavity are mixed withthose from the balanc.e arm, and are detected with acrystal diode. Figure 3 shows the ESR spectrum of
DPPH (2,2-Diphenyl-1-picrylhydrazyl) of about 50 J-lg.
DPPH is used as a standard sample to optimize themicrowave system.
A pulsed NMR system is used for measuring the pro-......

l V'
l J
It
\,

---

Time [250 Il s/div]
Fig. 4. The free induction decay signal of the water dopedwith a paramagnetic impurity.

ton polarization. The schematic diagram of the NMR
system is shown in Fig. 1. The RF signal produced bya function generator is pulsed and amplified by an RF
amplifier, whose maximum output is 500 W. The frequency and the width of the RF pulse are 12.75 MHz
and 2 J-lS , respectively. The power of the RF pulse is adjusted to a level called the 90° pulse, which maximizes
the amplitude of transverse magnetization of protons.
The pulse is passed through a tuner for impedance
matching and applied to the RF coil in the cavity.
Then, the NMR signal due to the free induction decay of protons is picked up by the same RF coil. The
picked-up signal is amplified by a preamplifier and its
proton resonance frequency component is obtained using a lock-in amplifier. Figure 4 shows the NMR signalof the water doped with a paramagnetic impurity.
We are currently tuning the microwave system andthe NMR system. These will be completed soon, andwe will start to polarize protons subsequently.
References
1) H. W. van Kesteren et al.: Phys . Rev . Lett. 55, 1642
(1985).
2) A. Henstra et al.: Phys. Lett . A 134, 134 (1988).
3) M. Iinuma et al.: Phys. Rev. Lett. 84, 171 (2000).
4) M. Hatano et al.: RIKEN Accel. Prog. Rep. 33, 182(2000) .
5) M. Hatano et al.: RIKEN Accel. Prog. Rep. 34, 196(2001).

195

RIKEN Accel. Prog. Rep. 34 (2001)

Development of Single Crystals of Aromatic Molecules Doped with
Pentacene for a Polarized Proton Target
M. Hatano,*l T. Wakui, H. Sakai,*l A. Tamii,*l and T. Uesaka*2
We are now developing a polarized proton solid target applicable at high temperatures (2: 77 K) and ina low magnetic field (:::; 3 kG). We plan to apply thistarget to study the structure of an unstable nuclei.
We will measure the reactions between an unstable
nuclear beam and the polarized proton target in the
inverse kinematics condition. We hope to obtain information on the spin of the single particle orbit of aknock-out nucleon by measuring the analyzing powerin the (p, 2p) or (p, np) quasi-free reactions. We canalso study the LS interaction between a proton andan unstable nucleus by measuring the elastic scattering between them. In such investigations it is crucial
to detect low momentum recoil protons to achieve highangular and energy resolutions. Therefore, a polarized
proton target which is applicable in a low magnetic
field is especially essential. The polarized proton target is also useful for various experiments, for example,a"+ p spin correlation measurement.
As a target material, we use a single crystal of aromatic molecules doped with pentacene (C 22 H 14 ). For
the host material we use naphthalene (ClOHS, melting point 80.5°C) or p-terphenyl ((C 6 H 5hC 6 H 4 , melting point 214°C). These host materials are suitable forcrystallization with pentacene.
The 7r-electron of the pentacene molecule has large
electron population differences among three Zeeman
sublevels in its optical pumped triplet state. This indicates that the electron is polarized. The electron
polarization is 73%. This value is independent of temperature and magnetic field. The electron polarizationis transferred to the protons by means of the integrated
solid effect (ISE) .1 ,2) Then proton polarization is transferred to the neighboring protons by spin-spin interaction. ISE is a kind of dynamic nuclear polarization.
The most significant advantage of this method is that
it is applicable in a low magnetic field. !inuma et al.
reported that proton polarization of 30% was achieved
with this method at a temperature of 77 K and in amagnetic field of 3 kG. 1)
It is known that the higher the purity of the hostmaterial, the higher the attainable proton polarization.
Therefore, we developed a purification system based on
the zone-melting method. 3 ) The crystallization process
is realized by the Bridgman method. 4 )The purification system is shown in Fig. 1. The hostmaterial is enclosed in a glass cell. The glass cell ispulled up at a speed of rv20 mm/h through a 20 mm¢
glass tube. Thirty heaters are attached to the glass
*1
*2

196

University of Tokyo
Saitama University

aromatic compoundionFig. 1. Aromatic compound purification system. Impurities accumulate gradually at the bottom of the glass
cell through the liquid region and the solid region alternately.

o ver melting
point region
silicon~heatercr--~~~g la ss ce l l

glycerin

Fig. 2. Aromatic compound crystallization system. The
single crystal of aromatic compound grows at theboundary between the temperatures above the melting
point and below the melting point.

tube at intervals of 9 cm in order to melt the host material so that melting and solidification of the host material occur alternatingly. Impurities accumulate gradually at the bottom of the glass cell during the passage.
Then we remove the part with the impurities and enclose the other part in the glass cell to be purified again
in the same way to achieve higher purity. We repeat
this procedure tow or three times .
The crystallization system is shown in Fig. 2. A
glass cell enclosing the purified host material and asmall quantity of pentacene is pulled down at a speedof rv 1 mm/h from the region above the melting temperature toward the region below the melting temperature. In this process, the bottom of the glass cell iscooled down gradually, and a single crystal grows fromthe bottom of the glass cell.
We have succeeded in fabricating a single crystalof naphthalene doped with pentacene and one of pterphenyl. Their pentacene molar fractions and crystal
sizes are shown in Table 1. The ISE system is being
tuned at RIKEN.5 ) We will start polarizing protons ina few months.

Table 1. Pentacene molar factions and crystal sizes.
host material
naphthalene
p-terphenyl

molar fractions
0.001 mol %0.01 mol %size of crystal
10 x 10 x 25 mm 3
7 x 5 x 15 mm 3

We are interested in studying other aromatic
molecules for a polarized proton target , for example,
anthracene (C 14 H lO , melting point 216.2°C) dopedwith phenazine (C12HSN2). We have already suc-ceeded in making a single crystal of anthracene with asize of 3 x 3 x 3mm3 .
References
1)
2)
3)
4)

M. Iinuma et al.: Phys. Rev. Lett. 84, 171 (2000).
A. Henstra et al.: Chern. Phys. Lett. 165, 6 (1990) .
W. R. Wilcox et al.: Chern. Rev. 64, 187 (1964) .
G. J. Sloan et al.: Techniques of Melt Crystallization,(Wiley-Interscience, New York 1988).
5) T. Wakui et al.: RIKEN Accel. Prog. Rep. 34, 194(2001).

197

RIKEN Accel. Prog. Rep. 34 (2001)

Accurate Calibration of 3He Polarization
S. Yamamoto,*l T. Uesaka,*2 T. Wakui, J. Nishikawa,*2 and H. Sakai*3
A RIKEN 3He target polarized by spin exchangewith optically pumped Rb vapor 1 ,2) has been appliedin nuclear physics experiments in 1996,3) 19984 ) and2000. 5 ) To obtain the absolute value of 3He polarization, we introduced a method based on the frequency
shift of the Rb electron spin resonance (ESR)6) in aprevious work.7) A typical Rb ESRfrequency and shift
are 12.203(5) MHz and 7(3) kHz , respectively, in ourcase. The uncertainty here is expected to be mainly
due to instability of the magnetic field produced bymain coils. The instability is about 20 mG at a magnetic field of 30 G. Thus, we need to measure the magnetic field with high accuracy in order to improve theprecision of the Rb ESR frequency.
For this, we introduced a commercial magnetometer
whose measurement range and resolving power are 2 G
and 10 ltG, respectively. We measured a weak magnetic field generated by current (rv 5 A) applied to themain coils. The Rb ESR frequency was measured simultaneously with the magnetic field using the method
described in Ref. 7. Time dependence of the Rb ESR
frequency is shown in Fig. 1 together with that of themagnetic field. We found that the fluctuation of the
Rb ESR frequency of 5 kHz is mainly caused by thefluctuation of the magnetic field. We corrected the Rb
ESR frequency, taking its magnetic field dependence
into account.
The measurements of the Rb ESR frequency werecarried out in the cases where 3He nuclear spin K isparallel (lK1B) and antiparallel (jK1B) to the magnetic field B of 25 G produced by the main coils. A 3He
nuclear spin was flipped using a nuclear magnetic resonance (NMR) setup of adiabatic fast passage. Figure 2
shows the Rb ESR frequency which was alternately obtained for each case. By using the magnetometer, wehave succeeded in obtaining a Rb ESR frequency witha precision within less than 1 x 10- 5 , which is an improvement from the previous work. 7)
The Rb ESR frequency shift /:).// is given by the Rb
ESR frequencies //(lK1B) and //(iK1B) in Fig. 2 as

18 .4418.43~>U

18.42 ~

C1>,.....

o·.....

18.41 (D'~S

18.40~

200

400
Time [s]

18.39

600

Fig. 1. Time dependence of the Rb ESR frequency and themagnetic field. The Rb ESR frequency was measured
simultaneously with the magnetic field .

I

I

I

•
8.666 r--

I

I

-

•
I

•

N
::r::

:::E
~ 8.664 r--

•

C)

I=:

0

Q)

;j

I

-

ESR Frequency (antiparallel)
ESR Frequency (parallel)

0"

...
Q)

~

-

8.662 r-0

8.660
0

0

0

I

I

2

4

0

0

I

6
Data Point

I

I

8

10

Fig. 2. A typical set of the Rb ESR frequency corrected
for the fluctuation of the magnetic field. The Rb ESR
frequency was measured in the cases where 3He nuclear spin K is parallel (lK1B : 0) and antiparallel(iK1B : e) to a magnetic field B.

/:l// = //ClK1B) - //(lK1B)

ItBgs
87r
[3 ]
h (21 + 1) K03//He He P3He,

where ItB is the Bohr magneton, gs is the electron gfactor, [3He] is the 3He density, and P3He is the 3He polarization. If 3He polarization is 100%, /:).// is 46.5 kHz
in our case.
Figure 3 shows the Rb ESR frequency shift, or the
3He polarization, as a function of the amplitude of the
*1
*2
*3

198

Toho University
Saitama University
University of Tokyo

3He NMR signal. The 3He NMR amplitude corresponds to a relative value of 3He polarization6) andwas measured with an uncertainty of less than 1%.
Therefore, the Rb ESR frequency shift should be proportional to the NMR amplitude. The solid line represents the result of least-squares fitting. Although thedata points are mostly on the fitted line, there still
remain some deviations of less than 0.4 kHz. The deviation corresponds to 8% for the Rb ESR frequency
shift. We assume that the deviation was mainly caused
by a stray field which was detected by the magnetome-

r--r---r--r--r-,---,,---,-,-,-,-,---,---.-..,--,--.-'-'--'-'--'--'-"""""""

ter. We plan to modify the setup to shut off the strayfield from the magnetometer.

15

6

N

References

2S

1) R. M. Herman: Phys. Rev. A 137, 1062 (1965).
2) T . G . Walker and W. Rapper: Rev. Mod. Phys. 69, 629(1997) .
3) T. Uesaka et al.: RIKEN Accel. Prog. Rep. 30, 139(1997).
4) M . Kurokawa et al.: personal communication.
5) J. Nishikawa et al.: RIKEN Accel. Prog. Rep. 34, 51(2001).
6) M. V. Romalis and G. D. Cates: Phys . Rev. A 58, 3004
(1998) .
7) S. Yamamoto et al.: RIKEN Accel. Prog. Rep. 33, 156(2000).

::r:

~

:aen

10

~

'1

N'

>.

III

()

c+

o·

~

Q)

;:J

cr
Q)
$..,

"'d
0

4

5

2

::J

~

~

o~~~~~~~~~~~~~~~~

o

100

200
300
400
NMR Amplitude [mY]500oFig. 3. The Rb ESR frequency shift as a function of 3He
NMR amplitude.

199

RIKEN Accel. Prog. Rep. 34 (2001)

Preparation of Single-Crystal C 60 for the Implantation of 19F( ~190)
W. Sato, K. Asahi, H. Deno, Y. Kobayashi, H. Ogawa,*1 A. Yoshimi, K. Yoneda, H. Watanabe, N. Imai,*2
K. Yoshida, K. Yogo,*1 H. Miyoshi,*1 D. Kameda,*1 and H. Nakahara*3
Fullerenes, represented by C 60 , are novel carbon allotropes of soccer-balI-like shapes consisting of a network of five- and six-membered carbon rings.1) The
unique structure of the molecules shows such intriguing properties as superconductivity, and it is interesting to provide insight into the electronic properties ofthe fullerene C60 . Through our previous study,2) thetime-differential perturbed angular correlation (TDPAC) method has been found to be exceedingly well
suited for the study of solid-state fullerenes because
it can provide direct information on both static anddynamic interactions between probe nuclei and the extranuclear field. Taking advantage of the spectroscopy,
we will apply the TDPAC method in this study using
19F as the probe. For the introduction of the probe
19F, the precursor radioactive nuclides, 190, as a secondary beam produced by projectile fragmentation of
22Ne are to be implanted in the solid C 60 . Since thepattern of the TDPAC spectrum, in general, becomes
simple when the probes are incorporated in a single
crystal, we have started to work on the production of
C 60 crystals, growing them as large as possible. The
production method of C 60 in progress is described in
the present report.
For the preparation of C 60 single crystals, we mostly
followed the method developed by Tachibana et al. 3 )Approximately 50 mg of 99.95% pure C 60 powder washeated at 250°C under evacuation to rv 1 X 10- 5 Torr ina Pyrex glass tube with an inside diameter of 8 mm ¢.
The tube was sealed after one-day heat treatment , andplaced in a horizontal quartz-tube furnace , on which akant hal line is coiled to produce the temperature gradients shown in Fig. 1. The C 60 powder at the end of the
Pyrex tube was sublimed at approximately 600°C andan aggregation of small single crystals was depositedat the cold center of the tube after 5 days. The crystals
were then sealed in vacuum in a Pyrex glass tube withan inside diameter of 13 mm ¢. With the crystals kept
at the right-side end, the tube was placed in anotherhorizontal quartz-tube furnace having the temperature
gradients shown in Fig. 2. In this furnace, the Pyrex
tube was moved slowly towards the left at a rate of 5
to 10 mm/day. Large single crystals with sizes of approximately 1 mm were grown at the cold center of thefurnace within 3 days.
For the purpose of the present study describedabove, larger crystals with a size of at least 3 mm are
requisite because excessive beam collimation leads to
*1
*2

*3

200

Department of Physics, Tokyo Institute of Technology
Department of Physics, University of Tokyo
Graduate School of Science, Tokyo Metropolitan University

g]

550

~

~

I-<
11,)

500

0..

8

11,)

~

450

400~~~~~~~~~~~~~~~

-60

-40

-20

20

0

40

60

80

Distance from the Cold Center (mm)Fig. 1. Temperature profile of the furnace for the sublimation of the C 60 powder.

550

f]
'-"

~

::s
.....
~

I-<
11,)

500

0..

8
~

450

400~~~~~~~~~~~~~~~

-80

-60

-40

-20

0

20

40

60

80

Distance from the Cold Center (mm)Fig. 2. Temperature profile of the furnace for the growthof single-crystal C 60 .

the reduction of the beam intensity, resulting in poor
statistics. Further improvement of the apparatus istherefore strongly needed.
References
1) H. W. Kroto et al.: Nature 318, 162 (1985).
2) W. Sato et al.: Phys. Rev. Lett. 80, 133 (1998) .
3) M . Tachibana et al.: J. Cryst. Growth 166, 883 (1996).

RIKEN Accel. Prog. Rep. 34 (2001)

RF Deflector System for RI Beams on RIPS
K. Yamada,* 1. Tanihata, T. Suda, and T. Motobayashi*
There are many nuclei in the neutron-rich side of
the nuclear chart which arouse much interest, for instance, the ones involved in the r-process and nuclei
with neutron halos. Therefore, various experiments using neutron-rich RI beams have been performed. On
the other hand, few experiments have been reported regarding proton-rich RI beams produced by projectile
fragmentation. However, proton-rich nuclei are also ofinterest. For example, the ones along the N = Z line
draw much attention due to their special nuclear structures affected by the neutron-proton pairing. Some
proton-rich nuclei are involved in the rp-process, theexplosive nuclear burning in novae. A major difficulty
for fragmentation-based proton-rich beams is in thepresence of unwanted nuclei in the secondary beamof interest. Fragment separators such as RIPSl ) select projectile fragments by their magnetic rigidity
XB = Bp = mvjZe. Because the velocities of thefragments are similar to that of the primary beam, theuse of a degrader following magnetic analysis enables
further separation of nuclei with the same AIZ ratio.
However, for a proton-rich nucleus, the tails of the
momentum distributions for less proton-rich species
are included, because their intensities are much higher
than the nucleus of interest. This happens particularly
among isotones, because their magnetic rigidities takealmost the same value.
To overcome the difficulty discussed above, we areplanning to develop a radio frequency deflector systemthat is expected to be installed in the RIPS beam line
to obtain high-purity proton-rich RI beams. Since different particles selected by RIPS have different velocities, the difference of their arrival times is determinedamong different species. By applying an RF voltage inthe direction perpendicular to the beam axis, the secondary beams are deflected depending on their arrival
time at the deflector. The frequency and the phase areset so that the beam of interest is not deflected andother unwanted beams are deflected.
Figure 1 shows the outline of the deflector system. It
consists of an oscillator synchronized to the cyclotron
RF signal, a controller circuit , deflector electrodes , slitsthat eliminate deflected beams, RF shields, high voltage insulators and a vacuum chamber. The bending
direction will be set to be vertical, and the system will
be installed between the Q9 lens and the F2 chamberof RIPS by replacing the existing switching magnet.
The system design will be realized soon.
References
1) T. Kubo et al.: Nucl. Instrum. Methods Phys. Res. B
70 , 309 (1992).

Y

DEFLECTOR
ELECTRODES

SLIT

1-1---

Q9

Q10

Qll

Q12

++- -------- -~ -f----F3

RF

1+-__ CYCLOTRONRF SIGNAL
TO MONITOR

Fig. 1. Outline of the deflector system.

Rikkyo University

201

RIKEN Accel. Prog. Rep . 34 (2001)

Development of an RF Ion Guide System
M. Wada, Y. Ishida, T. Nakamura, T. Sonoda,*l T. Oshima,*l Y. Nakai, T. M. Kojima, Y. Kanai, H. Oyama,
T. Kambara, Y. Yamazaki, A. Yoshida, T. Kubo, Y. Matsuo, Y. Fukuyama, K. Okada,*2 K. Noda,*3
H. Kawakami,*4 S. Ohtani,*5 and 1. Katayama*4
An rf ion guide system was proposed to obtain slow
or trapped radioactive nuclear ions which are primarily
produced by a projectile fragment separator. 1 ,2) The
energetic ion beams from the fragment separator are
firstly energy degraded by passing through a degrader
plate. The medium-energy ion beam thus obtained isthen injected into the He gas cell to thermalize theions. The stopped ions should be quickly extracted to
the vacuum and transferred to the downstream instruments. In the ordinary ion guide system, the t ransportof ions in the cell is carried out only by the gas flow.
If a large cell were used to stop relatively high energy
ion beams, it would take much more time than possible
loss processes such as charge exchange and diffusion to
the wall.
A fraction of thermalized ions in the He gas is known
to be in a singly charged state. The ions can be manipulated by an electric field. However, if a static electricfield is applied, the ions would be lost at the cathodeelectrode since the ion motion in such high-pressure
follows the electric force line. If, on the other hand,an rf field were applied in addition to the static field,
the average force due to the rf gradient field would
become repulsive against the electrode. The effective
electric field due to the gradient rf field at the tip ofthe electrode is
8mf.-L2 V 2Eeff ~ - - 3 '

e

ro

(1)

where m is the mass, f.-L the mobility of the ion in thegas, e the electric charge, V the terminal voltage ofthe rf potential, and ro the distance between adjacentelectrodes. In general, heavier ions at lower pressure
can be driven in a weaker rf field .
In a previous off-line test,3,4) multiple metallic plates
were used to form the rf electrodes and the distance
between the electrodes was 2.5 mm. More than 50%
transmission efficiency was achieved for Ta ions under
the conditions of He pressure of 30 Torr and rf amplitude of 50 V. The pressure used in this test was too
low for practical experiments. We set the target pressure at 150 Torr, which corresponds to the stopping
capabilit ies of 5 MeV lu for medium to heavy ions and
2.5 MeV lu for very light ions, if the depth of the cell is
*1

*2

*3
*4

*5

202

2 m. To operate the rf ion guide mechanism under suchhigh pressure, decreasing the ro is the most effective
way; increasing the voltage is limited by the discharge
problem. According to Eq. (1), transporting Li ions in
150 Torr He gas could be realized if fine structure electrodes with a distance of 0.3 mm or 0.5 mm between
electrodes were fabricated.
We fabricated such fine structure electrodes using aflexible printed circuit. Figure 1 shows the electrodes
for the nozzle part made of a printed circuit on a polyimide film. The arc pattern lines with an interval of
0.3 mm form ring electrodes by folding the film into a
corn shape. The straight part of the print pattern was
extended to form a cable as well as a feed-through up
to an rf divider circuit board which was placed outside
the vacuum. The large funnel structure part was also
made of the flexible printed circuit (Fig. 2). The total
number of electrodes for this part was more than 400

Cyclotron and Radioisotope Center, Tohoku University
Department of Physics, Sophia University
National Institute for Radiological Science
Institute for Particle and Nuclear Studies, High Energy Accelerator Research Organization
Institute of Laser Science, University of Electro-Communications

Fig. 1. Printed circuit fabricated on a polyimide film. Nozzle part of the rf ring electrode was formed by folding
this print pattern.

Fig. 2. Funnel structure part of the rf electrode assembled
in the gas cell. Diameter of the top (right side in the
figure) is 100 mm a nd the bottom is 5 mm. Nozzle partis to be placed at the left side of this structure.

Position

40

10Energy of Li-8 beam [MeVlu)

Fig. 4. Energy distribution of the 8Li beam after the wedge
degrader measured by a 700-J.Lm-thick Si detector.
Fig. 3. D2 magnet of RIPS and the rf ion guide test bench.

and the total capacitance measured at the source terminal of the rf divider circuits was more than 10 nF.
Two high-power amplifiers, which were originally designed for a piezo device, were used to drive the rf circuits with a frequency of ",600 kHz and an amplitudeof up to 200 V.
On-line test experiments are under way at the
RIKEN fragment separator, RIPS. A new beam port
was prepared particularly for this development at theside of the second dipole magnet (D2) where the second focal point (F1') from the first dipole (D1) was
obtained (Fig. 3). The magnification was 3.9 for thehorizontal direction and 8.7 for the vertical direction.
The focal point was momentum dispersive and the dispersion was as large as 42 mm/%, which enables us toperform energy compression using a wedge degrader.
Figure 4 shows energy spectra of the 8Li beam after the wedge degrader made. of Pyrex glass 33 mm inthickness with a wedge angle of 1.6 degrees. The test
beam of 8Li was produced from a primary beam of
100-MeV /u 13C and a Be target 0.75 mm in thickness.
The yield at the degrader was 1.1 x 103 atoms/pnA andthe beam size was as large as 60 mm in the horizontal
and 20 mm in the vertical directions. The stopping capability for Li ions is about 1 MeV /u if a compact-size
gas cell with 30 cm length is used for the test. The
acceptable beam fraction in such an energy range wasas small as 0.5%.
Although the Li beam is one of the most difficult
species in terms of the energy spread after the degrader, the stopping capability of the gas cell and therf voltage required for manipulating ions in the gas
cell, we chose 8Li as the test beam since the detection
efficiency is very high and we aim at trapping 11 Be for
future experiments on hfs spectroscopy. A test of thegas cell using the 8Li ion beam is in progress.
References
1) M. Wada et al.: Presented in the Int. Workshop on Ion
Guide Isotope Separator On-Line (IGISOL-6), Dubna,(1997) , unpublished.
2) I. Katayama et al.: Hyperfine Interact . 115, 165 (1998).
3) M. Wada et al.: RIKEN Accel. Prog. Rep. 33, 180(2000).
4) M. Wada et al.: RIKEN Rev. No.:U, 56 (2000) .

203

RIKEN Accel. Prog. Rep. 34 (2001)

Performance of Liquid Xe Scintillation Chamber with 20Ne Beam
T. Kato,* T. Doke,* J. Kikuchi,* H. Okada,* F. Nishikido,* Y. Matsui,*
K. Morimoto, and I. Tanihata
In the Radio Isotope Beam Factory (RIBF) projectat RIKEN, a variety of RI will be produced, andthe discovery of many new isotopes heavier than 0
is anticipated. To search for new isotopes in a regionaway from the stability line in the nuclear chart, theamount of beam irradiation required will increase because of the low production cross sections of these nuclei. Therefore, detectors which can withstand radiation damage due to heavy ions are required.
To satisfy such a requirement, the possibility of using liquid rare gas as a detector medium is considered.
Recently, a new liquid argon (LAr) ionization chamber
was constructed as a calorimeter and used to test forheavy ions with an energy of around 100 MeV /nucleon.
Excellent energy resolution of 0.6- 0.7% (FWHM)l)
was achieved for Ar and Ca ions, but the pulse heightsof the ionization signals changed with the beam intensity as a result of accumulation of Ar+ ions.
Next, the use of scintillation in liquid xenon (LXe) is
considered to eliminate this intensity dependence. The
decay time constants (4.3 and 22 ns) of the scintillation
light are comparable to those of plastic scintillators,
and the scintillation yield (Wph = 14.7 eV) is comparable to that in NaI (TI). LXe is expected to be thedetector medium, functioning as a timer and energy
counter with high resolution, high counting rate andresistance to radiation damage.
In order to study the timing and energy responses toheavy-ion beams of scintillation in liquid xenon (LXe),
the LAr ionization chamber has been improved. A
cross-sectional view is shown in Fig. 1. LXe was compressed in the internal vessel under vacuum. All heavy
ions with an energy of 100 MeV /nucleon stop in LXe.
Scintillation light produced by heavy ions was observed
using two photomultipliers (PMTs; HAMAMATSU,
R5900) through a MgF 2 window.
The test experiment was performed with a 20Ne
beam at 135 MeV/nucleon at the RIKEN ring cyclotron in September 2000. Aluminum plates of 0, 1,
3, 5, 8 and 10 mm thickness were used as a degrader
to change the beam energy. The beam energy wasmeasured after passing the aluminum plates using thetime of flight (TOF) between a plastic scintillator andthe LXe scintillation chamber. A beam spot of 10 mmdiameter was focused on the center of the LXe chamber. An effective area of 1 mm diameter in front of the
LXe chamber was selected by a veto plastic counter in
off-line analysis .
Figure 2 shows that the intrinsic time resolution with
Advanced Research Institute for Science and Engineering,
Waseda University

204

Pressure Gauge---.

HV, Signals

Beam

Fig. 1. Cross-sectional view of the LXe scintillation chamber.
800r---~--r-~~~...,..~~~........,r-~~.............,

80

1---'-........................ 70 ~700 1-.........
, ......, .......,.....,' i l ,,_.
_ _ _.....,:. " " " :, ' -.,. :
. ..
.
,...
: ..:
. .:. .' - 1 - :.
__:_. . . . . . . . . :. . .. . .:. .. . .: . . ..: . . .
: .. :
. .:
..

~~

Wj

~ 500

50 ~
40 ~

~ 400

' , ,

~

8' 300:~:::::Q':: .... :: ::::: 0:::::,1" :": :0::::

: : :

E

:::::f.o< :30 E=:1..'_,.'_"_'_"--'--'_ _ _ _---,,.\< 200• Energy output

100 1--....o...-.....................""+---'-..................."'""f------"'-1o00 . . :I '.: 20:~
10o Time resolution~~~~~~~~~~~~~L-~I~I~.~',~.,r

1.0E+02

1.0E+03

1.0E+04

1.0E+05u:50

1.0E+06

IntenSity [cps]Fig. 2. Intrinsic time resolution and energy output relative
to beam intensity. The plot of energy output for 1.3 x
105 cps was discarded, because the measurement was
not carried out under good conditions due to the ACcoupling of the ADC (LeCroy 2249 W).

one photomultiplier (PMT) was around 30 ps in sigma
up to a beam intensity of 1.3 x 105 cps. The time
resolution of the LXe scintillation chamber with two
PMTs is given by dividing the intrinsic time resolutionof 30 ps by V2, giving 21 ps in sigma. It is also shownin Fig. 2 that the energy output was constant for theincrease in the beam intensity. The difference was lessthan 1% and the energy resolution was 1.2-1.4% insigma. Figure 3 shows the relationship of the energy
output to the deposited energy in LXe. Nonlinearity of
the amount of scintillation light in LXe for the incident

800

Fig. 3. Relationship between the amplitude of the output
signals and the deposited energy in LXe.

The number of photons (N) that arrived on a photocathode of each PMT was estimated by the solid angles calculated along the track of the 20Ne beam. The
time and energy resolution was fitted by a function of(alVN + b), where a and b are parameters, and it became obvious that the number of photons determinedboth resolutions. This finding suggests that both resolutions will be improved by increasing the numberof photons. The solid angles were about 2% of 47r in
the experiment. We plan to construct a chamber toimprove the geometry of the PMTs , and test it withsome kinds of heavy-ion beams.
The results of this experiment have been submitted
to the Japanese Journal of Applied Physics.

energy is fairly small compared to that in other organicand inorganic scintillators.

1) A. Yunoki et al.: Nucl. Instrum. Methods Phys. Res. A
432, 332 (1999).

700

•

~ 600

..

<l

=

; 500
.:::
:::: 400

~

•

U 300
Q

-< 200

•

100

o
o

500

1000
1500
2000
Deposited Energy in LXe [MeV)

2500

3000

References

205

RIKEN Accel. Prog. Rep. 34 (2001)

Measurement of Depth of Interaction in a Segmented
Planar Ge Detector
E. Ideguchi,*l B. Cederwall,*2 T. Back,*2 1. Milechina,*2 Y. Gono, Y. Yang,
T . Teranishi,*3 N. Aoi,*4 D. Bucurescu,*5 and T. Kishida
Gamma-ray measurements using heavy-ion induced
reactions often suffer from the Doppler effect. Due tothe finite solid angle of the I-ray detector, Doppler
broadening deteriorates the energy resolution. Thiseffect is particularly serious when one uses so-called
inverse reactions. In order to correct for the energy
shifts originating from the Doppler effect, it is necessary to detect the directions of I rays emitted in thereaction and to reduce the solid angle subtended byeach Ge detector.
In order to achieve this aim, a detector complex consisting of a segmented Ge detector 1 ,2) and a clover Ge
counter 3) has been developed. 2) The planar Ge crystalof 5 cm x 5 cm with 2 cm thickness is used as a transmission type tlE I-ray counter, for which the cathodeis electrically segmented into 25 elements and each segment is of 1 cm x 1 cm square shape. The clover Ge
mainly detects Compton scattered I-rays from the segmented Ge detector. Doppler broadening is reduced
due to the small solid angle of each segment of theplanar Ge placed in front.
Recently, new techniques to enable the tracking ofI radiation in primarily Ge detectors are being developed which will allow the determination of the time
sequence of I-ray interactions and their respective positions in a detector, as well as their energies. 4- 6 ) The
I rays are detected by highly segmented Ge detectors.
Three-dimensional position determination in the detectors is achieved by analyzing the pulse shapes ofnet charge signals in the irradiated segments and mirror charge signals of the neighboring segments since
they reflect the interaction points of the , rays in the
Ge crystal. Tracking algorithms based on the Compton scatter formula are then applied in order to determine the energy, direction and interaction sequenceof incoming I rays. By applying a tracking techniqueto the segmented planar Ge detector as well one canobtain a higher effective granularity and therefore abetter Doppler correction. A necessary requirement,
however, is that a sufficiently high position resolution
for I -ray interactions in the detector volume can beobtained.
In order to determine the dependence of the pulse
shapes of signals produced in the Ge detector on the
*1
*2
*3
*4
*5

206

Department of Chemistry, Washington University, USA
Department of Physics, Royal Institute of Technology, Sweden
Center of Nuclear Study, University of Tokyo
Department of Physics, University of Tokyo
H. Hulubei National Institute of Physics and Nuclear Engineering, Romania

location of the interaction points, it was necessary
to introduce experimental conditions where primarily single-interaction events are considered. This wasachieved 7) by irradiating the segmented planar Ge detector with a collimated 137 Cs , -ray source and requiring coincidence between this detector and another(coaxial) Ge detector. The coaxial detector was also
collimated by a Pb slit collimator in order to detect
only I rays scattered at 90° in the segmented detector.
Energy gates were then applied to the detector signals
in order to select single Compton scattering events. In
this case, the energy of the Compton scattered, rays
is 288 keY and the energy deposited in the planar Ge
detector is 374 keY. The hole size of the Pb collimatorand the width of the slit were chosen to be 1.5 mm and
2 mm, respectively, in order to obtain a small geometrical uncertainty in the positions of the scattering points
due to the size of the collimators while maintaining areasonable counting rate. Gamma rays were irradiatedto the central segment (# 13) of the crystal, and theoutput signals from the cathode element # 13 and the
adjoining cathode elements # 8 and # 12 were used toobtain the net charge and mirror charge pulse shapes.
In the measurement, three different interaction depthsof 5 mm, 10 mm, and 15 mm in the center of the segment # 13 were chosen as well as one interaction point
at a 5 mm depth but 2.5 mm off-center.
A main goal of the present investigation was to identify the pulse shape parameters which may best serve
to determine the depth of interaction. By studying averaged pulses, for which the contribution from electric
noise has largely been canceled, we may easily identify
the main changes in the detector signals as a funct ionof interaction position. Averaged pulses from the anode and the centrally irradiated cathode segment # 13
recorded at the three different depths, 5 mm, 10 mm,
and 15 mm, are presented in Fig. 1. The figure showsa clear dependence of the pulse shapes as well as therelative timing of the anode and cathode signals on thedepth of interaction.
Clearly also more detailed features of the pulse
shapes are sensitive to the depth of interaction. However, in the present work, we have restricted ourselvesto the straightforward approach of using only the timing of the anode signal relative to the cathode element# 13, and the rise time of the signal from the cathodeelement # 13, which we identify as the most important
properties for determining the depth of interaction.
In the analysis, we use T50 as a measure of the arrival time of the charge at the anode relative to the10 ~----------------------------~

4 0 ~----------------------------~o(a) CHI: Anod e\'>
S - 10

o

...

~
~

I
I
I

o

-

:

I
I

:
:

I
I

:

I

0&0

C\l

::r:

5 mm depthu...... 10 mm depth

~

\\

- 20

'0 20

--- 15 mm depth

o
b

'.

o center . 15mm de plh

0>

b

-30
100
150
200
Time [4ns/ ch]

250

300

o
o cen ler . 5 mm deplh
6. 2.5mm r ighl. 5 mm deplh

I
o

50

00

o

~
~

I
I

10

60

o cen ler . 10m m deplh
60

(Jj

~

ZSl

6~

100
120
T50 of CH1 [4ns/ ch]140

10~----------------------------~

Fig. 2. Correlation diagram between T50 and Tgo-TlO for
four different interaction points. The inset shows a typical pulse shape used in the analysis and the timing of
TlO, T 50, and T go.

(b) CH2: Cathode #13'>
S - 105 mm depth

If.)------ 10 mm depth--- 15 mm depth

-20

- 30
50

100
150
200
Time [4ns/ ch]

250

300

Fig. 1. Averaged pulses for anode (a) and cathode (b)signals obtained by irradiating the center of the segment
at three different depths , 5 mm, 10 mm, and 15 mm.

timing of the constant fraction discriminator output ofcathode segment # 13. Here, T lO , T50, and T90 indicate the earliest time at 10%, 50%, and 90% of the
maximum amplitude of the pulse, respectively. The
difference between T 90 and T 10 was taken as a measureof the rise time of the pulse. In order to select eventswith only a single interaction in the Ge crystal, an energy gate around 374 ke V was applied to the integrated
anode and cathode element # 13 signals. In Fig. 2 acorrelation plot for the two independent time parameters, T 50 and T 90 - T 10 , is displayed for four different
interaction points in the detector. It can be clearlyseen that the (T 50 , T 90 -T lO ) pairs are distributed inseparate regions of the chart according to the depthof interaction. The distributions due to irradiation in
the center at 5 mm depth and 2.5 mm off-center overlap
almost completely with the central interaction points
at 5 mm depth as expected, since they are due to thesame depth of interaction. The overlap at the bordersof the distributions probably arises from the geometrical uncertainty due to the Pb collimator, and the wider
distributions for the deeper depths of interaction may
indicate the effect on the signal from multiple scattering in the crystal.
The finite opening angle of the collimator set-up

used in the measurement produced a geometrical uncertainty in the distribution of the interaction points of'Y rays in the Ge crystal. Monte-Carlo simulations using the code GEANT3 8 ) were performed 7) to estimate
this uncertainty and to compare the result with the distribution of experimental T50 values obtained by thepulse shape analysis. The geometrical uncertainties inthe depth direction were estimated from the simulation to be 1.13 mm, 1.26 mm, and 1.32 mm for 5 mm,
10 mm, and 15 mm depth, respectively, by assumingthat they have Gaussian distributions.
The uncertainties in the T 50 values are primarily a
combination of the geometrical uncertainty due to the
Pb collimators and effects intrinsic to the detector suchas electric noise, charge trapping etc. The intrinsic position resolution of the detector (for single interactions)
can therefore be unfolded by removing the geometricalcontribution estimated from the simulations. Basedon the results 7) of the pulse shape analysis and thesimulations, an intrinsic position resolution for single
interactions of the order of 1 mm was obtained for thedepth direction.
References
1) E. ldeguchi et al.: RlKEN Accel. Prog. Rep. 27, 121(1993).
2) Y. Gono et al.: Nucl. Phys. A 588, 241c (1995).
3) P. M . Jones et al.: Nucl. lnstrum. Methods Phys. Res.
A 362 , 556 (1995).
4) M . A. Deleplanque et al.: Nucl. lnstrum. Methods Phys.
Res. A 430, 292 (1999).
5) K. Vetter et al.: Nucl. lnstrum. Methods Phys. Res. A
452 , 223 (2000) .
6) J. van der Marel and B. Cederwall: Nucl. lnstrum.
Methods Phys. Res. A 437, 538 (1999).
7) E. ldeguchi et al.: to be published.
8) GEANT3, Detector Description and Simulation Tool
(CERN, Geneva, 1993).

207

RIKEN Accel. Prog. Rep. 34 (2001)

Ten-Segment Germanium Detector
S. Motomura,* S. Tanaka,* Y. Gono, T. Kishida, H. Watanabe, and K. Asahi
A telescope germanium (Ge) detector was developed. A telescope system was first prepared for theenergy correction of Doppler shifted energy of ,-rays
which were emitted from recoiling reaction productswith a large velocity such as 10% of the velocity oflight. 1) In this case, the telescope consisted of a segmented and a clover Ge detector. This system worked
well for Doppler correction as well as , -ray linear polarization measurement. 2 ,3) However, it was found thatGe detectors in two independent cryostats caused a reduction of detection efficiency in the telescopic mode.
To avoid this problem, one Ge crystal was segmented
to form the Ge telescope shown in Fig. l.
Sensitivity for ,-ray linear polarization was higher
with square segmentation for the front part of the telescope. This configuration does not allow the same electric field shape to form in all the segments. Therefore
it was necessary to test whether the square segmentation coaxial Ge detector could be used to keep highenergy and time resolutions. The energy resolutionsof all segments as well as efficiencies were measured aslisted in Tables 1 and 2. Energy resolutions are thesame as or better than those given in the specifications, except that given for 'Full. ' The 'Full' signal
was taken from the inner n-type electrode which wascommon for all the segments. This discrepancy mustbe further examined.
Considering the efficiency, the measured values of
the ten-segment Ge detector are consistent within afactor of 2. These values depend strongly on the set-

Table 1. Energy resolution.
Segment
number
1
2
3
4
5
6
7
8
9
10
Full

FWHM (keV)
at 1.33 MeV(Spec.)
2.93
2.24
2.58
2.11
2.47
2.16
2.83
2.38
2.08
2.92
3.0

FWHM (keV)
at 1.33 MeV(Measured)
2.80
1.91
2.24
1.96
2.24
2.13
2.67
2.33
1.93
2.97
3.56

(Full: Signal combining all charges
collected independently on each segment.)

Table 2. Gamma-ray detection efficiency of telescope detectors .
Gamma-rayenergy (keV)
122
344
1408

A

Ten-Segment Germanium
Measured
Simulation
0.011
0.020

B

0.00020.0001A

0.00270.00110.000440.00080.00460.00220.00070.0010B
A

B

25 Segment+ Clover0.009
0.00270.00030.00070.00043

A: Segmented Ge only.
B : Telescopic mode.

ting of discriminator levels for signals. Therefore, it
is not a straightforward comparison. However, the Gevolumes of the two systems are 198 cm 3 for the tensegment system and about 500 cm 3 for the 25 segment+ clover system. Considering this difference, these results indicate that the ten-segment telescope has very
high efficiency compared with that of the 25 segment+ clover system.
References
1) Y. Gono et al.: Nucl. Phys. A 588, 241c (1995).
2) H. Watanabe: Ph. D. Thesis, Kyushu University (2000).
3) H. Tsuchida et al.: KUTL Rep. 6, 92 (1997).
Fig. 1. Ten-segment Ge detector.

Department of Physics, Kyushu University

208

RIKEN Accel. Prog. Rep. 34 (2001)

Development of Ultrahigh Resolution Time-of-Flight Detector
for RI Beam at RIKEN
S. Nishimura, M. Chiba, M. Kurata-Nishimura, K. Morimoto, Y. Nishi,
1. Tanihata, T. Yamaguchi, and T. Zheng
In the RI beam factory (RIBF) project,1) it is absolutely critical to develop a new time-of-flight system.
The requirements for this are improved timing resolutions below 20 ps with high efficiency, use of fewer
materials, and operational at a high beam intensityof more than 10 6 cps as well as sufficient radiation
hardness against heavy ions for stable operation. For
heavy-ion beams, various kinds of detectors are used
as time-of-flight detectors.2,3) In this report, we focus
on the time-of-flight resolution of a well-known scintillation detector for the current RIPS and for the future
RIBF at RIKEN.
The test experiment was performed in the E1c beamline at RIKEN in November, 2000. The primary beamof 40 Ar is used at an energy of 95 Me V per nucleon.
The layout of the experiment is shown in Fig. 1. There
are two position-sensitive detectors PPAC (PI, P2)4)
placed upstream of the test detectors for precise position measurement at the position of scintillation detectors. The start timing of the beam is defined bya scintillation detector (SO). In addition, there are
four test counters (Sl, S2, S3, and S4) installed in
the light shield box. Each scintillation detector consists of two identical photomultiplier tubes directly attached to a scintillator with optical coupling of Bicron
BC630. Various kinds of scintillators and photomultiplier tubes are tested systematically to investigate theperformance of the time-of-flight resolution during theexperiment (See Tables 1 and 2.). The precise position
measurement of the primary beam within 1 mm is expected using two additional fiber scintillation detectors(FIl, FI2)5) which are installed downstream of S4.
In this test experiment, signals from photomultiplier tubes are digitized by leading-edge discriminators (Kaizu and Phillips 630) and sent to secondary
leading-edge discriminators to reshape the signals after a 100 ns cable delay. The timing measurement was
performed using two Kaizu time-to-digital converters(TDC-3781), for which precision of the timing measurement is about 25 ps per channel. The timing resolution of the electronics after the discriminator outputs is evaluated by comparing the timing jitter between two identical outputs from a discriminator channel. The intrinsic timing resolution of our electronics is
confirmed to be about 8 ps. The signal coincidence oftwo photomultiplier tubes from the start counter (SO)is used as a start timing, where low-loss microwave
cables (HUBER+SUHNER S-04272-B) are chosen to
obtain trigger signals faster than the TDC signals via
BNC cables (RG-58). All ADCs and TDCs of scintilla-

uum

~I

::r-4-

PPAC1 PPAC2i ~~FI1__-_-_-_-.:::::::::)F,2t

51

Df--'-------1152

E1

Fig. 1. Experimental setup at the E1c line of RIKEN .

Table 1. Characteristics of different types of photomultiplier tubes. 6 ) The R3809U-52 is the photomultipliertube with two microchannel plates inside its tube.
R5900-L16 is a metal-channel dynode used for S4,
where signal outputs from No. 6- 11 in 16 channels aretotalled. (PMT: type of photomultiplier tubes, R.T:
rise time, T.T.S: transit-time spread, G: gain, and Det.:
detector types)

PMT

R. T (ns)

R2083
R4998
R3809U
R5900

0.7
0.7
0.15
0.6

T.T.S (ps)
370
160
<25
180

G (x 106 )
2.5
5.7
0.2
2.0

Det.
SO, 8281
83
84

Table 2. Characteristics of various scintillators 7) used in
the experiment. BC422Q is quenched with 0.5% benzophenone to improve timing properties. (Scinti.: typeof scintillators, R.T: rise time, L.O: light output, A.L:
attenuation length, and Det.: detector types used as
default.)

Scinti.
BC404
BC418
BC422
BC422Q

R. T (ns)
0.7
0.5
0.35
0.10

L.O (%)

A.L (cm)

Det.

68
67
55
19

160
100
8
<8

*
*

80, 8481, 8~' 83tion detectors were input into a computer via CAMAC
and stored in a disk for off-line analysis. As a CAMAC
crate controller, TOYO-CCj7700 is selected.
The timing resolution of each detector was investigated in the off-line analysis. Figure 2 shows ourpreliminary time-of-flight spectrum between SO and209

RlKEN MACHINE·STUDY#92
.cI

~&:;

:I

Q

2000 -

U

1750 -

1500 t-cr - 14.3 ps1250 f-1000 f750 r-

500 r-

2500

I

I

I

I

I

I

60

80

100

120

140

160

Time-of-Flight

I

180
200
(25ps1ch)

Fig. 2. Time-of-flight spectrum between SO and Sl after
the slewing correction.

81. As a scintillator, BC422 and BC422Q with dimensions of 50 x 40 x 0.5 mm 3 and 40 x 20 x 0.5 mm 3
in width x height x thickness are chosen for 80 and
81, respectively. About 15% of the improvement intime-of-flight resolution is achieved after the slewing
correction using the pulse height information of eachphotomultiplier tube as well as a correction of timing
as a function of position dependence. Notably, ourpreliminary results show that the time-of-flight resolution between 80 and 81 is about 14.3 ps. This indicates that the intrinsic timing resolution of 80 and
81 is about 10.1 ps(!) on the average, which is nearly210

the limit of the timing resolution that can be possibly
achieved for the current electronics itself and would be
the best time-of-flight resolution achieved by a scintillation detector. In the future, it would be possible toachieve a better timing resolution of below 10 ps using
faster timing electronics, particularly for the TDC.
A new time-of-flight detector has been developed using fast scintillators and fast photomultiplier tubes.
Our preliminary results show that the intrinsic timing resolution of about 10 ps is achieved using 40 Ar
ions with an energy of 95 Me V per nucleon. FUrther improvement is expected using faster electronics.
While systematic study of the scintillation detector isin progress using scintillators of various sizes, thicknesses, and types as well as different types of photomultiplier tubes . In the future, it is necessary to investigate its radiation hardness as well as its operation under a high beam intensity to evaluate its performance
under a realistic environment of the RIBF.
References
1) I. Tanihata: J. Phys. G: Nucl. Part. Phys. 24, 1311
(1998).
2) T . Chujo et al.: Nucl. Instrum. Methods Phys. Res. A
383, 409 (1996).
3) F. Tokanai, K. Morimoto, M. Kurata-Nishimura, I.
Tanihata, and S. Yamada: submitted to IEEE Trans.
Nucl. Sci.
4) H. Kumagai , N. Fukuda, A. Ozawa, K. Summerer, and
I. Tanihata: RIKEN Accel. Prog. Rep. 33, 163 (2000).
5) K. Morimoto, F . Tokanai , M. Kurata-Nishimura, I.
Tanihata, Y. Hayashizaki, and S. Yoshida: IEEE Trans.
Nucl. Sci. (2000), to be published.
6) Hamamatsu Photonics: Photomultiplier Tubes and Related Products (1998) .
7) BICRON: Organic Scintillators, Related Materials andDetectors (19~7) .

RIKEN Accel. Prog. Rep. 34 (2001)

Detection of Heavy Ions by a Superconducting Tunnel Junction
H. Sato, T. Ikeda, K. ~awai, H. Miyasaka, T. Oku, W. Ootani,*l, C. Otani, H. M. Shimizu,
Y. TakIzawa, H. Watanabe, K. Morimoto, and F. Tokanai*2
One of the important applications of the superconducting tunnel junction (ST J) is as a high-energyresolution photon detector which exceeds the energy
resolution of the conventional semiconductor detectors
because of the small gap energy of the superconductor( rvme V). We have been developing the ST J, 1 ,2) and theenergy resolution of 41 eV in full width at half maximum (FWHM) for 5.9keV X rays has been achieved,l)which is the best result in Japan.
The ST J can also form the basis of a good detector
for heavy ions, which is very useful in applications toa beam profile monitor under a heavy radiation dose 'and to a very fast time-of-flight (TOF) counter. The
passage of a heavy ion through an ST J results in quasiparticles being instantaneously generated in a small
region called hot spot along the heavy ion track. The
superconducting current is assumed to be suppressedat the hot spot causing a decrease in the ST J criticalcurrent. If we apply a bias current across the ST J, thisdecrease switches the ST J voltage from 0 to gap voltage (rvmV). Heavy ions can thus be detected by monitoring this voltage switching. The switching speed is
expected to be in the order of 1 to 10 ps, which enables
a very fast particle detector to be realized. With regard to the radiation hardness, recent study has shownthat only slight damage has been observed with Au 15+
irradiation of 0.92 Grad. 3 )We began the development of the heavy-iondetection system using the ST J, and the ST J response to heavy ions was experimentally studied at
t~e RIKEN Ring Cyclotron Facility.4)
We fabricated an Nb-based STJ with a layer
structure of Nb (200nm-thick)/AI (10nm)-AIO x /Nb(150 nm) in our fabrication facility at RIKEN. The
ST J has a square shape, the upper Nb layer being 20 /-Lm x 20 /-Lm and the lower Nb layer being
40pm x 40 pm.
An ST J chip was cut out of the fabricated wafer toa size of 5 mm x 5 mm and set in a liquid He cryostat.
A plastic scintillator was placed upstream of the cryostat to monitor the beam intensity and to be used as
one of the TOF counters. Bias current h was supplied
to the ST J by a function generator through a variable
resistor. A time-to-analog converter (TAC) was triggered by the switching signal of the ST J and stopped
by the delayed scintillator signal. The timing spectrum was obtained by constructing a histogram of thepulse height of the TAC output with a multichannel*1*2

I nte~national Center for Elementary Particle Physics, UniverSIty of Tokyo
Department of Physics, Yamagata University

50'iii" 40

E
::I

~ 30

"Gi

'>' 20-~ 1.7±O.2ns(FWHM)

10o·200

J j.1 ,I.I

o

.L

./.

200

400

600

800

time (ns)Fig. 1. Time spectrum obtained from the TAC. Full scaleon the horizontal axis (1 f.1s) corresponds to the time
range of the TAC.

analyzer.
A 40 Ar beam at 95 MeV/nucleon was introduced
into the cryostat, and the size of the beam spot was
adjusted to a 10 to 15 mm diameter to illuminate theentire chip. The energy of the 40 Ar beam was attenuated by passing through the plastic scintillator, thetwo Al windows at the cryostat and a 43-mm-thick liquid He column and the kinetic energy as it entered the
STJ was 44.4 MeV /nucleon.
The incident rate of 40 Ar ions was measured by theplastic scintillator as 400 cps, and the voltage switching rate of the ST J was about 1.1 cps. The rate ratio is consistent with the area ratio of the beam crosssection and the ST J area. The rise time of the typical output voltage from the ST J was 67 ns, which was
predominantly limited by the analog bandpass of thetransmission cable connecting the ST J to the amplifier.
The obtained time spectrum is shown in Fig. 1. The
time width of the peak was 1. 7 ± 0.2 ns in FWHM; thiscorresponds to the time resolution of the detection system that was determined by the time walk of the discriminators and time jitter of the signals from the ST J
and the plastic scintillator. The signal cables and dataacquisition system were not adequate for transmitting
fast pulses to identify the intrinsic timing characteristics of the ST J . An improved measurement systemwith more appropriate cables for fast pulse transmission is planned.
References
1) H. Sato et al.: Jpn. J. Appl. Phys. 39 , 5090 (2000).
2) C, Otani et al.: Jpn. J. Appl. Phys. 39, 1710 (2000).
3) L. Frunzio et al.: Jpn. J . Appl. Phys. 37, Suppl. 2, 40(1998).
4) H. Sato et al.: Nucl. Instrum. Methods Phys. Res. A
459, 206 (2001).

211

RIKEN Accel. Prog. Rep. 34 (2001)

Tritium Gas Handling System Operation in 1999/2000
T. Matsuzaki, K. Nagamine, K. Ishida, S. N. Nakamura,*l M. Tanase,*2 M. Kato,*2
K. Kurosawa,*2 and H. Sugai*2
A tritium gas handling system (TGHS) has been
constructed to produce high-purity D-T target gas for
precise measurements of the a-sticking probability inthe muon catalyzed d-t fusion cycle at the RIKENRAL Muon Facility. At the experiment site, the systemenables us to purify the D-T target gas by removing
the 3He component (a decay product of tritium), toadjust the D /T gas mixing ratio and to measure thehydrogen isotope components. A schematic diagram
is shown in Fig. 1. The system is designed to handle
the D-T gas with negative pressure and a total volumeof 1.1 liter. Tritium gas with the inventory of 56 TBq(1500 Ci) has been operated in the system.
In the period of 1999/2000, we conducted three major works for the TGHS and reported their details as
follows.
(1) Replacement of the mass separation column inthe radio-gas chromatograph
The radio-gas chromatograph system was originallydeveloped at the Department of Radioisotopes in
JAERI in order to separate hydrogen isotope components for tritium gas enrichment and hydrogen isotope
analysis. I) By connecting a small ion chamber to agas chromatograph, the tritiated hydrogen components
can be measured more quantitatively. The present gas
chromatograph system has been compactly designed
to allow installation in the glove box. The system consists of a thermal conductivity detector , separation column and ion chamber with 0.5 cm 3 sensitive volume.
The separation column of 3 mm diameter and 3 m longis filled by aluminum oxide powder coated with manganese chloride (MnCI 2) and is cooled by liquid nitro-gen. The gas sampling unit with a volume of 0.8 cm 3
is designed to be remotely operated by the TGHS control system and the sampled gas is transported to theseparation column by neon carrier gas.
The separation column deteriorated for an unknown
reason and the obtained mass separation of hydrogenisotopes was poorer than the designed performance.
Therefore, we manufactured a new separation column
with the same specifications and its performance wasconfirmed at JAERI using deuterium gas before thereplacement work. In December 1999, we replaced theseparation column of the gas chromatograph with thenew one. We measured the mass separation in thegas chromatogram of deuterium gas and the result isshown in Fig. 2. A satisfactory mass separation was
obtained between D2 and HD components, where HD
is an impurity in the crude D2 gas.
(2) Replacement of titanium getter 3
Three titanium getters are installed in the TGHS .
Figure 3 shows the cross-sectional view of the triplex
structure with double ends. The secondary layer calleda "sweep line" is a space for argon gas flow to cool the
primary space and sweep away possible permeated tritium . The third layer called a "cooling line" is also aspace for argon gas flow to be used as required. This
structure minimizes the tritium permeation from theprimary space at an elevated temperature because theheater is positioned at the center of the primary space
enclosed by two layers with argon flow. The thermocouple located inside the heater enables temperature
control with the aid of a PID process controller. Another thermocouple is positioned in the titanium layer
as a secondary backup. In Fig. 1, Ti-getter 1 is used
to collect the D-T bas in the constant volume for disposal. The other two T i-getters are used to collect
the residual hydrogen in the releasing gas from the

1000

<

.-

-=

r-------------r-. ~

~

~
0

100

0

C,)
~

10

HD

-

.-

1-

1- - - - - - - - - - - - - _ · _ · - -1------------1+-1
1

.-

1
0

Fig. 1. Diagram of tritium gas handling system.
*1

*2

212

Tohoku University
Japan Atomic Energy Research Institute (JAERI)

10

15Time (m in)

20

25

30

Fig. 2. Obtained gas chromatogram of deuterium gas using
the new separation column.

Sintered mesh

10 J1 mHeater and thermocouple• - -~- Titanium sponge
E

E
C'?
,....

.q-

Thermocouple

Sweep line
Cooling line
Sintered mesh
10 J1 mFig. 3. Cross-sectional view of titanium getter .

radio-gas chromatograph and evacuation system. The
titanium sponge of 250 g is loaded around the heaterin the primary space and corresponds to the hydrogengas absorption capability of 46 liters. The releasing gas
is introduced into the titanium sponge layer throughthe sintered mesh. Then, the hydrogen gas is absorbed
and the residual gas passes out upward, while the tritiated methane is not absorbed in the Ti-getter. The
conditioning of Ti-getters was conducted by evacuationfor eight hours at an operating heater temperature of
570°C. The absorption performance of Ti-getter 3 was
confirmed by introducing tritium gas and the obtained
tritium reduction factor measured by tritium monitor
1 was about 1/5 in the single-pass mode.
Recently, the thermocouple located inside the heater
broke down in Ti-getter 3 and the heater temperature
could not be controlled. A new titanium getter withthe same specification was manufactured and it was installed at the same time as the replacement work of theseparation column was carried out in December 1999.

After the investigation at the manufacturing company,
it was found that the thermocouple wire was broken
at the connection part between the thermocouple wirefrom the heater and the lead wire to the hermetic seal
shown in Fig. 3.
(3) Tritium gas supplied by Chalk River Laboratory
In a series of muon catalyzed d-t fusion experiments,
we have mainly used tritium gas supplied by JAERI.
The tritium gas has been produced there through the
6Li(n, a)T reaction by neutron irradiation to 6Li-AI
alloy targets in a nuclear reactor. 2) The tritium gas
is extracted from the irradiated 6Li-AI alloy in a vacuum furnace and isotopically enriched by applying theradio-gas chromatograph technique. I) Removing the
3He component, as a further purification step, is carried out using a palladium filter. The purity of tritium
isotope is 99.1 % with an impurity of the H component
which is originally contained in the 6Li-AI alloy.
In January 2000 , we imported tritium gas of 56
TBq (1500 Ci) to UK from Chalk River Laboratory
in Canada. At this time, the tritium handling facility at JAERI was under reconstruction and the ChalkRiver Laboratory is the only organization in the worldthat supplies tritium gas commercially for scientific research. The tritium gas was placed in two gas cylinders and transported to the RIKEN-RAL Muon Facility. The gas cylinders were then installed in the TGHS
and the tritium gas was transferred to the system. In
Canada, tritium is extracted from heavy water (D 2 0)
used at CANDU reactors by the cryogenic distillation
method, where tritium is produced in the heavy waterby neutron irradiation. The purity of tritium isotope
is 99.1 % with impurities of D (0.07%) and H (0.67%).
References
1) M . Tanase, M. Kato, K. Kurosawa, S. Motoishi,
S. Okane, H. Sugai, M. Fujie, K. Onoma, and H.
Yamabayashi: J. Nucl. Sci. Technol. 22 , 147 (1988).
2) H. Kudo, M. Fujie, M. Tanase, K. Kato, K. Kurosawa,
H. Sugai, H. Umezawa, T. Matsuzaki, and K. Nagamine:
Appl. Radiat. Isot. 43, 577 (1992).

213

RIKEN Accel. Prog. Rep. 34 (2001)

Optical Detection of Nuclear Spin Precession for the Observationof Nuclear Casimir Effect in 131 Xe
K. Yogo,* A. Yoshimi , K. Sato,* K. Sakai,* and K. Asahi
We aim at observing the Casimir effect in a nuclear system which manifests itself in nuclear spin
precession. The Casimir effect 1 ) refers to an observable change in a bound system of charged particles,
which occurs when the surrounding vacuum is restricted by placing, for example, a pair of parallel
conductingplates. Because of the boundary condition
imposed by the plates , the vacuum fluctuation effectdiffers from the one in free space , resulting in a shift
in the energy of the system, depending on the gap between the plates. Recently, observations of the Casimir
effect in a neutral atom 2 ) and macroscopic bodies 3 )have been reported.
Here, we use a 131 Xe nucleus placed in a static magnetic field Bo as a probe to observe the vacuum fluctuation. In this case, the effect of the vacuum fluctuation would be dominated by a virtual process inwhich the 131 Xe nucleus jumps from the ground state(In = 3/2+) to the nearby first excited state (1/2+)
and returns, emitting and reabsorbing a virtual photon. If the space around the 131 Xe spins is sandwichedby two conducting plates aligned perpendicular to thez-axis (taken parallel to the Bo field) , then the nuclear Zeeman sublevels m are expected to show tiny
but finite shifts depending on m; the energy shifts
for sublevels m = ±3/2 are larger than those form = ±1/2 since the emission of photons from the
m = ±3/2 is considered to be more restricted thanthat of photons from m = ±1/2. Such an effectwill be observed in a 131 Xe spin precession as threesplit frequencies , or as "side bands" around the central frequency corresponding to m = +1/2 f-+ -1/2transition in the Fourier transform of the precession
signal. The estimated size of the shifts according
to Cheon 4 ) is b.E rv 10- 11 - 10- 10 eV /b, where thedistance b between the plates is expressed in cm ,while recent calculations 5 ) suggest much smaller values b.E rv 10- 19 - 10- 18 eV /b 2 . The splittings dueto the Casimir effect should be clearly distinguishedfrom trivial quadrupolar splittings 6 ) stemming from apossible shape asymmetry in the 131 Xe gas container.
In the planned experiment, 131 Xe gas contained in a
glass cell is spin-polarized through spin-exchange collisions with Rb atoms, which is polarized by the optical pumping method with circular polarized 795 nm D1
light from a diode laser (Fig. 1). Once 131 Xe nuclei arepolarized , the pumping light at the cell is turned off

Tokyo Institute of Technology

214

Fig. 1. Setup for the observation of nuclear spin precession
with probe light. The conducting plates are removed
during the pumping phase. CP: circular polarizer.
PEM: photo elastic modulator. LP: linear polarizer.
PD: photodiode. PC: personal computer. DAC: digitalto-analog converters. ADC: analog-to-digital converters.

and the conducting plates are placed to modify the vacuum , and an rf field is applied to tilt the spins with respect to the Bo field. The spin precession thereafter isdetected based on the inverse process of the pumping,with linear polarized probe light from a single-mode
diode laser. The small amount of circular polarization
component is introduced in the probe light after passing through the cell because the Rb vapor in the cellshows circular dichroism due to spin exchange with thepolarized Xe nuclei. A photoelastic modulator (PEM),
which functions as a chopper of polarized light , enables
us to perform a lock-in detection for measuring a slightchange in the polarization of the probe light which reflects the Xe polarization. Thus far , we have succeeded
to polarize Xe spin. At present, the above detection
method for the Xe spin precession is in progress in the
RIKEN- TITech collaboration.
References
1) H. B. G. Casimir: Proe. K. Ned. Akad. Wet. 51 , 793(1948).
2) C. I. Sukenik et al.: Phys. Rev. Lett. 70, 560 (1993).
3) S. K. Lamoreaux: Phys. Rev. Lett. 78, 5 (1997).
4) I.-T. Cheon: Hyperfine Interact. 78 , 231 (1993).
5) K. Naito et al.: Prog. Theor. Phys. 97, 749 (1997).
6) Z. Wu et al.: Phys. Rev. Lett. 59 , 1480 (1987).

RIKEN Accel. Prog. Rep. 34 (2001)

Development of Nuclear Spin Maser for Low Density Spin System
A. Yoshimi, K. Asahi, K. Yogo,* K. Sato,* and K. Sakai*
We have developed a new type of spin maser which
is applicable to low density spin systems. The nuclear spin maser, in which nuclear spin polarization
contiguously precesses with a constant transverse polarization, will enable a high-sensitivity detection ofa small energy shift of nuclear Zeeman levels. Sucha method is necessary for experiments related to fundamental symmetry, such as investigations of electric
dipole moments of nuclei.
In a conventional spin maser, the feedback oscillating field which enables spins to precess contiguously
in spite of the transverse relaxation is produced bya precession-induced current in a coil wound aroundthe spin system. 1) Therefore a high-density polarized nuclear spin (polarization P r-v 10%), typicallyr-v 10 18 em -3, is necessary. We proposed an "active"
spin maser which can oscillate at a low spin density
where the feedback field is artificially produced basedon the detected spin direction. 2) This method can beapplied to a nuclear system which cannot be obtainedwith high density, such as stored neutrons (r-v 10cm- 3 )and radioactive nuclei (r-v 108 cm- 3 ).
We have successfully realized the operation of an active spin maser with the polarized 129Xe nuclear system (I = 1/2). Spin polarization of 129Xe is producedby the spin exchange interaction with a laser-polarized
Rb atom. The precession signal of 129Xe, which isdetected by the pickup coil, is sent to the operation
circuit in order to produce the feedback signal for realization of the spin maser. The feed back signal is fed
to the drive coil to apply the feedback oscillating field
onto the precessing spins. The feedback field tends totilt the polarization vector to the transverse plane sothat the spin polarization continues to precess with aconstant angle from the quantization axis. The maser
signal of Xe in an active feedback operation is shownin Fig. 1 together with that in conventional maser operation. The maser frequency is v ~ 3.5 kHz which
depends on the static field Bo ~ 3.0 G.
We are currently developing a new detection systemof spin precession for producing the feedback field. The
purpose of this development is to realize a maser operation with a frequency (r-v 10Hz) at which the spin
precession of low-density nuclei can be observed witha high signal-to-noise ratio. The schematic setup is
shown in Fig. 2. 129Xe gas is confined in a glass cellconsisting of two parts, a masing cell (top) and a probing cell (bottom). The pumping laser light irradiates
the masing cell. Rb atoms in the probing cell is notpolarized because the spin relaxation of Rb is short,
1 msec. The spin precession of 129Xe causes the

430

400

2000

460

2030

2060

:;-

.E;

4.0: (b)oI-H-+1~~"'''''''''''''''''-''

a;
c:
en
U5

.EHj ~

1000 Time

o

30

500

(52.....2000

2510

2500

700

Fig. 1. Maser oscillation signals of 129Xe in (a) a conventional spin maser, and (b) a maser incorporating theartificial feedback system.

')..,/4 - plate
Rb lamp~umping J~ Diode laser;o~':;.::tOJ(u (18~. I

D1 filter.........:::.........
i .........:---......

Xe cell

Probe light .........::::........

.
¥'..::....::.: .. .:.::......

/PEM.....'0r:;==::::::j,ref.

.

Dnve COil___ Linear Polarizer". D· H... Photodetector..........

Fig. 2. Schematic setup of a maser incorporating the optical detection system.

slight polarization of Rb atoms due to the spin exchange collision. Then, the spin precession of 129Xe
can be observed by detecting the instantaneous spin
direction of the Rb atoms. The spin direction of the
Rb atoms is observed by measuring the circular polarization component in the transmitted light which irradiates the probing cell, where the circular polarization
is detected by a photoelastic modulator (PEM) afterconversion to linear polarization. We are currently arranging the optical setup and designing the cell.
References
1) M. G. Richards, B. P. Cowan, M. F. Secca, and K.
Machin: J. Phys. B 21 , 665 (1988).
2) K. Asahi et al.: Czech. J. Phys. 50 Suppl. 1, 179 (2000).

Tokyo Institute of Technology

215

RIKEN Accel. Prog. Rep. 34 (2001)

Calibration of Deuteron Polarimeter DPOL for the Measurement of
the 12C(d, dt) Scattering in Highly Excited Continuum
H. Kato,*l Y. Satou, H. Sakai,*l A. Tamii ,*l K. Sekiguchi,*l K. Yako,*l S. Sakoda,*l M. Hatano,*lY. Maeda,*l N. Sakamoto, T. Ohnishi, K. S. Itoh,*2 H. Okamura,*3 T. Uesaka,*3
K. Suda,*3 J. Nishikawa,*3 and T. Wakasa*4
In order to search for Double Gamow-Teller(DGT)1 ,2) resonances, we have measured polarizationtransfer coefficients of the 12C(d, d') scattering. Since
the DGT resonances are expected to exist in highly excited continuum of 12C, we have measured the reactionin the excitation energy region of Ex < 60 MeV. For
this purpose we have calibrated the effective analyzing power of the focal plane Deuteron POLarimeter,
DPOL ,3) in the corresponding deuteron energy range,i.e., 210 < Ed < 270 MeV.
The DPOL is located at the second focal plane of
the spectrometer, SMART.4) A full view of the DPOL
is illustrated in Fig. 1. The DPOL consists of two
MWDCs, scatterers (SC), a hodoscope (HOD) and acalorimeter (CM). Incoming deuterons are scattered in
the SCs and ejectile particles are detected by the second MWDC and the HOD. The SCs are composedof plastic scintillators and polyethylene plates. The
DPOL utilizes the 12C(d~ d) reaction for the vector polarization measurement and the 1H( d~ 2p) reaction for
the tensor polarization measurement. The vector andtensor polarizations of incoming deuterons can be measured simultaneously.
In the calibration of the DPOL , a faint polarized
deuteron beam was directly injected into the SCs. The
beam energy was lowered to the appropriate energies
by adjusting the thickness of aluminum degraders. The
obtained energy dependence of the effective analyzing
powers is shown in Fig. 2. iTll is the vector analyzing
power of the 12C(d~ d) reaction in a scattering angle
range of 5° < () < 14°. T 20 and T22 are the tensor
analyzing powers of the 1H(ct: 2p) reaction in ranges of
0° < () < 10° and 3° < () < 12° , respectively. Relative energies of two protons in the CM system are
selected as E rel < 3 and E rel < lOMe V in the analysis of T 20 and T 22 , respectively. The scattering angle ranges and reaction energy ranges are determinedas the figure of merit (FOM) of each analyzing power
reaches a maximum. The FOMs and thicknesses ofscatterers are compared with those of the polarimetersat Saturne5 ,6) in Table 1. The FOMs of the DPOL aresmaller than those of Saturne due mainly to the thickness of the scatterers. However, the DPOL has anadvantage in that the vector and tensor polarizations
can be measured simultaneously, while at Saturne, twodifferent polarimeter systems must be used. Therefore,
the DPOL is expected to have fewer systematic errors
*1

*3

216

University of Tokyo, *2 University of Tsukuba
Saitama University, *4 RCNP, Osaka University

Fig. 1. A full view of the DPOL.

Vector0.4

II

Tensor

0 .4

I

0.3 -

-

0 .2 -

•-

0 .1-

0 .0
200

•

•

•

iT 11
I
220

I

I

240

260

0 .2

I

.
• • .
I

T 22

•

r- •

I

•

-

0 .0 f-' -- ------ -- - - - - - - -

T 20

r-

-

- 0 .2260- 0 .4
200

• I

220

Ed [MeV)

I

I

240

260

-

260

Ed [MeV)Fig. 2. The energy dependence of the effective analyzing
power of the DPOL.

Table 1. FOMs and thicknesses of scatterers. The difinition of the FOMs is adapted to that of Saturne. The
FOMs are defined as in Refs. 5 and 6.

DPOL
SaturneFl1(10- 2 )
1.91
4.2

F 20

F22

(10- 2 )0.60
1.2(10- 2 )0.59
1.0

thickness(g/cm 2 )C:4.2 H:0.47
C:8.2 H:1.1

in the measurement.
References
1)
2)
3)
4)
5)

P. Vogel et al.: Phys. Lett. B 212, 259 (1988).
N. Auerbach et al.: Ann. Phys. 192, 77 (1989).
S. Ishida et al.: AlP Conf. Proc. 343 , 182 (1995).
T. Ichihara et al.: Nucl. Phys. A 569, 287c (1988).
B. Bonin et al.: Nucl. Instrum. Methods Phys. Res. A
288, 389 (1990).
6) S. Kox et al.: Nucl. Instrum. Methods Phys. Res. A
346 , 527 (1994).

RIKEN Accel. Prog. Rep. 34 (2001)

Computing Environment of the RIKEN Accelerator Research Facility
T. Ichihara, Y. Watanabe, A. Yoshida, and K. YoshidaIn this report, we describe the recent computing environment of the RIKEN Accelerator Research Facility(RARF).
(1) UNIX cluster server
Figure 1 shows the configuration of the UNIX cluster server of RARF, which was installed in 1998. Fivenodes of UNIX servers, three of which are True 64
UNIX (alpha) and two of which are Solaris, are connected via the Gigabit Ethernet using a 1000 BaseSX
multimode optical fiber. The utilization of the Gigabit
Ethernet ensures the fast file access of the remote nodeand eliminates the network traffic jam. RARFAXP is
the main server for mail, text processing, user homepages and general computing. RARFAX1, RARFAX2,
and RARFSUN are used mainly for intensive data
analysis and large-scale calculations. RARFNFSO isa dedicated Network File Service (NFS) server whichis equipped with 2.8 TB (400 GB x 7) raid5 work disks.
The Veritas File System (VxFS) , which is a kind of logging file system, was adopted for the raid file systems
to obtain high performance in file operation and fast
file system recovery (fsck) after system failure.
RARFLX1 and RARFLX2 are installed at the IF
counting room to serve the working terminals during
the experiment. A Linux OS is adopted for RARFLX1and RARFLX2. All seven nodes share a common N etwork Information Service (NIS) and NFS system toNlshlna BI~.1F,'" ------ ---- -- - ------ --,RARF Gigabit UNIX Server
RIKEN

form a UNIX cluster. Several kinds of tape drives, including AIT-2, DLT, DDS4, DDS3 and 8 mm ones areconnected to the UNIX cluster. A load sharing facility(LSF) is installed for the batch queuing system.
Secure Shell (SSH) was installed for all the nodes.
The use of SSH is strongly recommended for remotelogin and file transfer to ensure security against data
sniffing. The Secure Sockets Layer (SSL )-encryptedInternet Message Access Protocol (IMAP) service isavailable at the RARFAXP. An anonymous ftp service is operating at RIKSUN (ftp.riken.go.jp) whicharchives 400 GB of useful software for research, including Linux and TeX distributions, GNU software and alarge amount of free software for PC, Mac and UNIXsystems.
(2) VMS system
Figure 2 shows the old system of the RARF offline cluster, which consists of nine nodes of OpenVMS / AXP system. These nodes are connected by
100Mbps FDDI and 10Mbps Ethernet. This VMS
cluster was the main off-line system at RARF before
1998. Since users of the VMS systems are migrating toother systems such as the UNIX cluster, terminationof the operation of the VMS system is currently underdiscussion.
(3) Online DAQ system
The VMS-based Data Acquisition (DAQ) system(-----------~~~~~;~~~;-'I

RIKAXP
4-CPU
512MB Memory

CentralGigabitSwitch(L2 )~------u

System, page, library etc.
AXPNEWRAIDs (perm disk) 50GB

r======i 278 GB RaidS (work)_ _ _--' --L-J

ATEMP1 A

RARF
GigabitRouter
(L3 )

Bldg.

LAN

Fig. 1. Configuration of the RARF UNIX cluster.

Fig. 2. Configuration of the old VMS cluster.

217

is used for several experiments including RIPS. The
CES 2180 Auxiliary Crate Controller accelerates the
CAMAC read operation to approximately l.4 p,s/word
read. 1) A Linux-based fast DAQ system was developed recently for a SMART experiment. 2 ) A CC7700
and PC-Linux-based DAQ system is also available forexperiment. 3 ,4)(4) Wide-Area Network (WAN) environment
RIKEN is connected to the Inter-Ministry research
information network (IMnet) at the speed of 15 Mbps
and this bandwidth will be updated to 50 Mbps inearly 200l. For the international connection, RARF
joined the Asia-Pacific Advanced Network (APAN)
which has a bandwidth of 70 Mbps over the Pacific
Ocean. Thanks to the APAN, stable access to the USA
and Europe ESnet sites has been achieved.

218(5) Electronic-mail address
The electronic-mail address for a general user of the
RIKEN Accelerator Research Facility is described asfollows , where the userid should be replaced by user's
login name of the RARF UNIX Cluster.
userid@rarfaxp.riken.go .j p
References
1) T. Ichihara et al.: IEEE Trans. Nucl. Sci. 36, 1628
(1989) , see also http://www.rarf.riken.go.jp/rarf/exp/
comp/2) H. Okamura et al.: Nucl. Instrum. Methods Phys. Res.
A 443 , 194 (2000).
3) H. Baba et al.: RIKEN Accel. Prog. Rep. 34, 221(2001).
http://rarfaxp.riken.go.jp;-iwasa/cc7700.
4) N. Iwasa:
html

RIKEN Accel. Prog. Rep. 34 (2001)

CAMAC Data Acquisition System for the NIRS /HIMAC Facility
H. Otsu* and T. Kobayashi*
A new CAMAC data acquisition system has been developed for experiments at a secondary beam course in
the Heavy Ion Medical Accelerator in Chiba (HIMAC).
In the facility we have carried out experiments mainly
on measuring the (p, 2p) reaction from unstable nuclei.
The new porting system has the following characteristics:• The system is suitable for data production rates
typically ranging from 100 to 100 k words/so• A cost-effective system can be realized by dividing
the system into several, easily exchangeable parts,
which leads to lower costs.
• The raw data format can be fully compatible
with those of the conventional DAQ system in the
RARF /RIPS facility.
• A compact DAQ system is desired, which can be
replaced in RARF /RIPS in the near future.
(1) Hardware configuration (see Fig. 1)
This system consists of three computers. One is a
CAMAC ACC K3976, which takes typically 1.8 f.LS fora single CAMAC function. A DAQ software package(EXP9X 1 )) is available with a different hardware configuration (K3976- K3929-Linux PC). The other two
are linux PCs with Intel Pentium family processors.
The upstream linux PC , called the 'front-end ,' is specified to transmit data up to 32 x 16 kB on K3976 memory to memory on the PC. CC7000 and its interface
have no direct memory access (DMA) property. Instead, the front-end PC has a device driver specified
to transfer 16 kB data at once without other processinterruptions. This extension enables the system toachieve a transfer rate of 360kB/s, about half that of
the original EXP96 system. The spill-off transfer (1.5 s
for 32 x 16 kB) is available in the HIMAC synchrotron
facility. Thus , no dead time occurs in transferring data
to the front-end PC. The data are directly stored on
hard disks or tape storages mounted on the front-end
PC and partly distributed to the downstream (backend) linux PC. In the back-end PC , analyzer processes
are run. A private network with a crossed Ethernet cable connects two linux PCs. The front-end PC is thecore part of this DAQ system.
(2) Software configuration (see Fig. 2)
K3976 programs are almost the same as the original
EXP96's. For compatibility with the RARF /RIPS raw
data format of a 16 kB unit, several codes are replaced ,mainly to realize continuity between units.
The CC7000 Linux device driver, developed andmaintained by the SMART group, is used as a basefor the front-end PC. The code to transmit 16 kB data
Department of Physics, Faculty of Science, Tohoku U niversity

LinuxBOXl

z.,
()

:I0

...
()

~

..
II

e
~

LinuxBOX2

-.;

ethl

e
~

II
.a
.2
u

,;?, 0,L

Fig. 1. DAQ system consisting of three computers. ACC
K3976 reads module data and stores them in the memory. When the memory is full or a user interruption
occurs, these data are transferred to the front-end PC
and stored on a disk or a tape.

===

CAIlAC Command/ Data~'" C~~~d/Lo~d ..

CAMAC Modules

DATA

I .DATA (IBkB .Unlt)/Statuo...............

I..J\~C: ..1~ooo Device Dr~
Commandi I

DATA/Statu.

~ Control command ~~_.-I DISK:/dev/hdXX I~ - - I DDS: / dev/slX I
I DATA

CfCket Cliev................ l .~~~~ .~~?~~~~kelSe~ACknO"I.d~~TAi I

Back-end""~Ic&;~e0 c&;a~ze~ c&;a~e~I~otolromcEW/Disp0.----U-s-er--,

I

Front-end/

Fig. 2. Block diagram of the software configuration.

219

at once is added in the device driver. As a result, an
OS clock is delayed depending on the frequency of datatransfer. The OS clock is restored from a CMOS clockon the PC when the stop command is given.
From the front-end PC to the back-end PC, the sampled data are transferred by a client-server program
pair with a protocol of TCP . In the back-end PC,
data analysis is performed. Codes compatible withthose used in the RARF /RIPS facility are available.
In order to conserve the rate of transferring data to
the front-end PC, only limited processes are allowed220

to run. In contrast, many processes are allowed in the
back-end PC because they have no influence on thefront-end PC.
In summary, it is found that the DAQ system functions well in the RIMAC facility. This system is acandidate for the smooth replacement of the current
VAX/J11 system used in the RARF/RIPS facility.
References
1) S. N. Nakamura and M. Iwasaki: RIKEN Accel. Prog.
Rep. 30, 152 (1997).

RIKEN Accel. Prog. Rep. 34 (2001)

Development of New Data Acquisition System BabarlDAQ
for Nuclear Physics Experiments
H. Baba,*l S. Takeuchi,*l K. Yamada,*l S. Shimoura,*2 and K. Ieki*l
We have developed a new data acquisition (DAQ)
system "BabarIDAQ." The previous RlKEN standard
CAMACt system 1 ) consisted of a CES2180 auxiliary
crate controller (ACC), a VAX computer, Kinetic 3922
and a Kinetic 2922 Q-BUS Interface for 3922. However, as the CES2180 ACC is out of production andthe number of VAX computers is declining, the development of new DAQ systems is necessary for future
generation experiments.
BabarlDAQ employs personal computers (PCs) witha RTLinux 2) operating system, Kinetic 3922 crate
controller and Kinetic 2915 PCl Interface to 3922.
RTLinux is the real-time operating system variant ofLinux that is released under the GNU General Public License and can be freely used. The BabarlDAQ
processes each event using a PC instead of an ACC.
Using RTLinux for event processing, the BabarlDAQ
performance is reached at the same level as that of theprevious system. For event processing, a user may add
a program in the C language instead of the assembler
language used in the previous system.
BabarlDAQ includes "Anapaw," which is a useful
analysis software that runs under Linux. Anapaw
is based on PAW 3 ) which uses the CERN Program
Library 4) and is compatible with "Analys" which isused in the previous system. Anapaw has the sameuser interface for both on-line and off-line analyses.
For on-line use, Anapaw receives data from Analyzer,
which is one of the components of BabarlDAQ, while
Anapaw can also read data from files for off-line analysis.
Thus, BabarlDAQ is very cost-effective and users
can change from the previous system to BabarlDAQ
easily.
The configuration of BabarlDAQ is shown in Fig. 1.
The main components of BabarlDAQ are the Collector,
Driver, Transfer, Database, Controller, Recorder, andAnalyzer. Each component, except for the Collector,
Driver and Transfer, can be distributed to PCs that
communicate with each other through ethernet. The
Database manages status data (e.g., run information ,current block data, scaler data), and provides these forother components. The Controller is the only component which has a user interface, and the user can control BabarlDAQ through the Controller. The Recorderstores raw data which come from Transfer on storage,
hard disk or magnetic tape. The Analyzer, which isa front-end program for on-line software such as Ana*1*2

Rikkyo University
Center for Nuclear Study, University of Tokyo
Computer Automated Measurement and Control

Parallel Highway

Fig. 1. Typical configuration of BabarlDAQ. Some client
pes can lie on the ethernet.

~

Computer system boundary

Fig. 2. Operation of the Driver and Transfer. The Driver,Transfer and shared memory are located in the same
computer region.

paw and Status Monitor etc., receives block data fromthe Database. The Collector loads the Driver and executes the Transfer when data acquisition is started.
The Driver acquires data from CAMAC and stores
data in a buffer which is located at a shared memory region. The Transfer observes a shared memory,and transfers data to the Recorder and Database when
the buffer becomes full. Since the Driver and Transf er communicate which each other through the sharedmemory, and the Collector is front-end for the Driverand Transfer, these components must exist in the same
computer region. The Driver and Transfer operations
are shown in Fig. 2.
The Driver checks the Look-At-Me (LAM) signal every 50 J.LS using a RTLinux periodic tack. While it takes

221

Table 1. Performance of CAMAC access. Interrupt latency is the period between CAMAC set LAM signal
and the RTLinux handler is taken up by IRQ that is
not used in BabarlDAQ .

100 ,-~--~----------------------------~

80

No data transfer
Single Action
1 Word Read
1 Word Write
Overhead
Block Read Action
1 Word Read
Interrupt Latency

Time (J.Ls)
8.5
11.0
11.0
16.8
2.6
4.5

CAMAC: Kinetic 3922 + 2915 PCI Interface
CPU: INTEL Cere Ion 450 MHz
OS: Linux 2.2.13 + RTLinux 2.0

up to 600 J.LS to start a handler in a standard Linuxand there could easily be a more than 20 ms latency
for a periodic task, a RTLinux periodic task can run
within 35 J.LS of its scheduled time. With two buffers
in a shared memory, the Driver can acquire data fromCAMAC even while the Transfer is accessing buffereddata.
We have developed a device driver for a Kinetic
2915 interface to a 3922 crate controller running on
RTLinux. The performance of CAMAC access is listed
in Table 1. Owing to the RTLinux, these times are notaffected by any other consumer process. The single
action response time is 8.5 J.LS at the no-data-transfer
mode, and 11.0 J.Ls at the read-action or write-action
mode. In the Block-read-action mode, which is oneof the Kinetic 3922 + 2915 action modes, once thecrate address, station number, subaddress, function
and transfer-count are set at the 2915 CNAF and thetransfer-count register, new data are automatically set
at the 2915 FIFO register for the transfer-count times
at which each data is read out from the 2915 FIFO register. This mode is useful for LeCroy FERA, FERAcompatible, Memory and Phillips modules that areable to read sequentially. In this mode, it takes up
to 58.4 J.LS to read 16 words , while in the other singleaction mode, it takes up to 176 J.Ls.
BabarlDAQ has been introduced for nuclear physics
experiments using the RIKEN projectile fragment sep-

VERSA bus Module Europcard

222

...
..
.....
,
....... . .....
.. ..
"f.

t··~.

.:

...

20

Event rate (kcps)

Fig. 3. Live time of BabarlDAQ in a typical experiment at
RIPS.

arator (RIPS). Figure 3 shows the live time of BabarlDAQ in a typical experiment at RIPS. Live time iscalculated based on the ratio of the total event number to the accepted event number by CAMAC. In thisexperiment, typical event size is about 80- 90 words
and the event rate is 0.2 kcps to 1.8 kcps, and the acquired data is stored on magnetic tape. This result is
no worse than that of the previous system. It should
be noted that the stored data have no errors, in spiteof the high rate and long duration of the experiment.
We will continue to explore means of developing ofBabarlDAQ in order to achieve performance improvement, for example, not only using CAMAC and PCs
but also combining ACC or VME. t
References
1) T. Ichihara et al.: IEEE Trans. Nucl. Sci. 36, 1628
(1989).
2) http://www.rtlinux.org/
3) http://wwwinfo.cern.ch/asd/paw /4) http://wwwinfo.cern.ch/asd/cernlib/

6. Material Analysis

RIKEN Accel. Prog. Rep. 34 (2001)

Fabrication of Nanoparticles in Polymer by Ion Implantation
T. Kobayashi and M. Iwaki
A polyimide film was implanted with Ag, Cu, Fe,K, Pd, and W ions using the four available accelerators with the energy from 100 to 380 keY. The beam
was scanned over a set area (400 cm 2 for Ag and W
implantation, and 9 cm 2 for the other ions) so that thefiuence would be the same for all the irradiated specimen areas. The fiuence ranged from 1 x 10 15 cm- 2 to
5 x 1017 cm -2, and the current density was kept to 0.1
to 3 f-tAcm-2 at a pressure below 1 x 10- 5 Pa.
Cross-sectional transmission electron microscope(TEM) observations were performed to observe any
growth of metallic particles using a 200 ke V JEO L
2000-FX electron microscope. The implanted specimens were packed in epoxy resin, and the 100-nm thickcross-sectional samples were prepared using a LeicaULTRACUT UCT with a diamond knife. The surface
composition was obtained from Rutherford backscattering spectroscopy (RBS) spectra. The RBS measurement was performed using a pellet ron accelerator
in RIKEN. The energy and the scattering angle of the
He ion beam were 1.5 MeV and 160 0 •Figure 1 shows the cross-sectional TEM image of
specimen implanted with silver ions at a fiuence of1 x 10 16 cm- 2 . The formation of particles of about 5 nm
in diameter was observed at around a depth of 50 nm.
The diameter of the particles increased with the magnitude of the fiuence until it reached about 10 nm inthe specimens implanted at a fiuence of 1 x 10 17 cm- 2 .
These results suggest that silver atoms implanted inpolyimide migrate easily during irradiation. The electron diffraction pattern of the specimen implanted at
a fiuence of 1 x 10 17 cm- 2 shows that implanted silver atoms exist as face-centered cubic (fcc) crystalline
particles. The crystalline particles were also observedin the cases of the copper- and palladium-implanted

specimens.
In the cases of iron-, potassium-, and tungstenimplanted specimens, no particle formation was observed in the implanted layers. An increase in electron
density was observed at around depths of mean ion
ranges due to implanted atoms. However, no diffraction pattern related to implanted atoms was observed
by electron diffraction spectroscopy.
It was concluded that noble metals implanted inpolyimide tend to form nanoparticles and that chemical activities of implanted atoms may control the particle formation.
Figure 2 shows the RBS spectra of a silver- anda tungsten-implanted specimen at a fiuence of 1 x
10 16 cm- 2 . The depth profiles of these two ions arealmost same. The oxygen concentration in the implanted layer decreased dramatically. The proportionof nitrogen atoms at the surface was difficult to estimate, because its signal overlaps with the signal foroxygen arising from 0 beneath the implanted layer. At
any rate, little difference was seen between these two
spectra in the region corresponding to the concentration of nitrogen and oxygen. On the other hand, thespectrum shows that the density of carbon atoms in
the tungsten-implanted layer was higher than that of
the silver-implanted one. This means that a chemicalinteraction exists between tungsten and carbon, rather
than between tungsten and oxygen. In this case, we
can speculate that the formation of metallic particles
is suppressed by bonding between the implanted atoms
and carbon, which in turn, affects the migration of theimplanted atoms.
4000

r ····
3000§2000 r ' .

8

1000

o
o

,

!

~

1

!

- - Polyimide (pristine)
C

~
~

x

Ag 1x1016cm- 20

W 1x1016cm- 2.. ......

"'15

N

0

~W
x

.\

~~
~
100

-

co

x ~~
:0
:0

x

0
0
0

...,;~ r~ ~
200

300

400

ChannelFig. 1. A cross-sectional TEM image of the specimen implanted with silver at 1 x 10 16 cm - 2.

Fig. 2. RBS spectra of silver- and tungsten-implanted specimen at a fluence of 1 x 10 16 cm - 2 .

223

RIKEN Accel. P rog. Rep. 34 (2001)

Direct Speciation of Sulfur in Marine Sediments by
High-Resolution PIXE
K . Maeda, T. Hasegawa,*l H. Hamanaka,*l K . Hasegawa,*l and N1. Maeda*2
We have developed a high-resolution P IXE systemfor chemical state analysis in atmospheric air. 1 ,2) In
the present work we apply this system to measure
the chemical shifts of Kal,2 line of sulfur in marine
sediments in order to examine t he possibility of direct speciation of sulfur in such delicate environmental
substances. 3)
The experimental setup is almost the same with thatreported in the previous paper 2) except that an entrance slit and a remote controllable XYZ target stage
were newly attached to the system. A target sample
was placed in air and bombarded with a 2.1 MeV proton beam of 3 mm diameter.The X-rays emitted fromthe target passed through the entrance slit and werediffracted by a flat analyzing crystal. T he diffracted Xrays were then detected by a position-sensitive proportional counter ( P SPC) and recorded on a 512 channel
analyzer. The entrance slit was made 0.3 mm in widthand placed at 5 mm distance from the proton beam
spot on the target . It worked to restrict the shape andposition of the X-ray source exactly. The target sample was moved repeatedly by a programmable stage
controller in order to reduce the sample damage by
proton bombardment. The analyzing crystal used was
NaCI (200) . One channel of the PSPC corresponds toO.140eV in the energy region of S Ka l ,2 (2 .31 keV) .
The precision of chemical shift measurements was estimated to be ± 1 channel by measuring S Ka spectraof MoS 2, Na2S03 and Na2S04 .
The marine sediment samples were collected in the
Sagami Bay, Japan, from the water depth of one thousand meter using a corer. Immediately after the sample collection, the core sample was cut into 1 cm-thickslices, frozen and stored in a freezer. The day before
the PIXE measurements the sliced samples were defrosted . Small portion of the samples were collected
on membrane filters, · washed with a small amount ofMilli-Q water and then stored in plastic containers.
The membrane filters loading the sediment samples
were cut into two or three pieces each, and set on plastic target holders and directly submitted to the PIXE
analysis.
Sulfur Kal ,2 spectra obtained from two depths(6.5 cm and 8.5 cm) in the sediment core sample areshown in Fig. 1 together with the spectra from reference targets MoS 2 (8 2-) and Na2804 (8 6 +) . The peak
position of the 8 Kal,2 from the sediment at t he depthof 6.5 cm is near to that of MoS 2. On the other hand ,the peak position of the 8 Ka l ,2 from the sediment
*1
*2

224

College of Engineering, Hosei University
Tokyo University of F isher ies

1.

5

(a)!
.

-4- :sedimemt at ::!depth 6.5 em:

.

:

:

:

+--+MoSt-+ Na S0

4

260

300

2:

1.0

2

160

180

200

220

240

280

PSPC position (channel number)

Fig. 1. Ka1 ,2 spectra of S in t he sediment samples at thedepths of (a) 6.5 cm and (b) 8.5 cm. Beam current
80nA; measuring t ime (a) 700s; (b) 600s: maximum
counts (lchannel) (a) 32; (b) 18. Sulfur concentrationsin these samples were around 1%.

~~ 'C' 240
a. Q)

~ ~ 236

~

::l

if)

Qi

~

c: 23215 § 228"0nj'e:2, 224
C+-----~----~------.---~

u

o

Q)

5
10
15
depth in sediment (em)20

Fig. 2. Centroids of S Kal ,2 spectra obtaip.ed from thesediment samples at different depths in the core sample.

at the depth of 8.5 cm is between those of MoS 2 andN a2S 0 4. The latter spectrum seems to be composedof two or more components.
Measurements of S Ka specta were carried out
several times for each sample. Repeated measurements indicated that the sediment samples were oxidized by air to some extent during the handlingand measurements .3) The centroids of S Kal,2 plotted against the depth in the sediment core in F ig. 2
were obtained by summing the spectra of duplicate
measurements, which were carried out within fifteen
minutes after taking the samples from the containers.
The centroid positions in each pair of the duplicate
measurements agreed within 3 channels although t hecounting rates were very small. From Fig. 2, we may

suppose that the ambience of the sediments near theinterface between the sediment and marine water was
rather oxidative and the ambience of the sediments atthe depth around 6 cm was rather reductive. The highresolution PIXE is considered to become a useful toolfor direct speciation of S in environmental substances,although more rapid measurements are desired. Development of a highly sensitive high-resolution PIXE
system is in progress.

References
1) K. Maeda, K. Hasegawa, H. Hamanaka, and K.
Ogiwara: Nucl. Instrum. Methods Phys. Res. B 134,
418 (1998).
2) K. Maeda, A. Tonomura, H. Hamanaka, and K.
Hasegawa: Nucl. Instrum. Methods Phys. Res. B 150,
124 (1999) .
3) K. Maeda, T. Hasegawa, H. Hamanaka, K. Hasegawa,and M. Maeda: Int. J. PIXE 10, 47 (2000).

225

RIKEN Accel. Prog. Rep. 34 (2001)

Slow Positron Yields from Some Porous Materials
L. Wei, N. Suzuki, J. Kim, F. Saito, Y. !toh, A. Goto, T. Kurihara, Y. Nagashima, and T. Hyodo
The slow positron yields from a solid are affectedby many factors, such as positron penetration depth,
positron diffusion length, trapping by defects and surface state, and there are several characteristics necessary to realize highly efficient moderator. The positron
work function at the surface must be negative. Furthermore, the materials should have high density, sothat more positrons can be slowed down quickly in the
crystal structure, and then the thermalized positron
can be re-emitted at the surface. Finally, the moderator material must have a high positron mobility or long
diffusion length, so that the positron can reach to thesurface and successfully exit to the vacuum. Besides
these characteristics, the effective emission surface also
plays an important role which is well clarified by recent studies on porous nickel and tungsten multi-wires.
Therefore, there is possibly room for further increases
in the slow positron yield. In this work, we report thefirst measurement of slow positron yields from several
porous materials which have a large aspect ratio or
surface-to-volume ratio and a stable physical property.
The materials used in this study are ,8-SiC whiskers,,8-SiC beads, tungsten powder and carbon fibers. The
slow positron yield measurements were carried out on
the magnetically guided slow positron beam lines at
RIKEN. The two beam lines are equipped with an
E x B energy filter and a bending magnetic solenoid,
respectively, to ensure that no fast positron can arriveat the sample chamber. For the calculation of efficiency
E, 100% positron transmission efficiency of the beamline is assumed.
The overall moderation efficiencies E for ,8-SiC
whiskers, ,8-SiC beads, tungsten powder and carbon
fibers have been measured to be 0.58-0.71 x 10- 4 ,0.17 X 10- 4 , 1.2 X 10- 4 and < 0.04 x 10- 4 , respectively.
In this experiment, the 1-mm-diameter tungsten powder was pasted on 1.5 mm Al foil. The obtained efficiency, 1.2 x 10- 4 , is comparable to that of tungsten
polycrystal foil .1)
The preparation conditions for the tungsten powder were not optimized in the present study. First,
the annealing temperature was 1100°C, which is lower
than that conventionally used for tungsten annealing(rv 2000° C). Secondly, during the preparation of the226

moderator, the annealed tungsten powder was dippedin ethanol before being pasted onto the Al foil. Finally,
the tungsten powder was not pasted uniformly or regularly well onto the Al foil because of our lack of experience. However, by overcoming the above problems in
the processing, it seems reasonable to expect that themoderation efficiency for tungsten powder may reachthe high 10- 4 range, the value obtained by using thetungsten overlapping mesh. 2 )The moderation efficiencies obtained for all the ,8SiC moderators are below the 10- 4 level, which is
at least several times lower than the estimate fromre-emission measurements, but still tens of times
higher than that obtained using transmission film
moderator.3 ,4) SiC is a potential candidate for a robustand efficient positron moderator, because of its large
negative work function, considerable diffusion lengthand stable physical and chemical properties. The SiC
whiskers and SiC beads have either a large aspect ratio or surface-to-volume ratio, thus they are expected
to provide high moderation efficiency. However, themoderation efficiencies obtained are away from the predicted value. One probable reason for this is the process used to prepare the moderator. Another reason
may be the surface state, which affects the positronemission. We expect that proper surface treatment
and a well-designed SiC/foil arrangement will improvethe moderation efficiency.
In conclusion, slow positron yields from several materials with porous structures have been measured on
slow positron beam lines in RIKEN . ,8-SiC whiskers
have a proposed moderation efficiency E in the high10- 5 range and tungsten powder in the low 10- 4 range.
References
1) S. Pendyala and W. McGowan: J . Electron Spectrosc.
Relat . Phenom. 19, 161 (1980).
2) Y. Nagashima, T. Kurihara, F. Saito, Y. Itoh, A. Goto,
and T . Hyodo: Jpn. J . Appl. Phys. 39, 5356 (2000) .
3) R. Suzuki, T. Ohdaira, A. Uedono, S. Ishibashi, A .
Matsuda, S. Yoshida, Y. Ishida, S. Niki, P. J. Fons,
T. Mikado, T . Yamazaki, S. Tanigawa, and Y. K. Cho:
Mater. Sci. Forum 714, 255 (1997).
4) A. Uedono: private communication.

7. RIKEN-BNL Collaboration on Spin Physics Program

RIKEN Accel. Prog. Rep. 34 (2001)

Experimental Activities in the RIKEN BNL Collaborationfor Spin Physics at RHIC
M. Ishihara and G. Bunce
The RHIC Spin Project is the integrated effort ofaccelerator, experimental and theoretical physics tostudy polarization phenomena in high-energy hadroncollisions using polarized proton beams at RHIC. We
have made significant progress in the project this year
achieving the first successful storing and accelerationof polarized proton beams at RHIC.
RHIC provided the first collision of gold ion beams
in June, 2000 at VSNN = 56 GeY, followed by the luminosity run through summer at JSNN = 130 GeY.
In the PHENIX experiment, we have recorded about
5 million events on tape out of 45 millions minimumbias events, which translates to 4.1 j.Lb- 1. We haveobtained the first set of physics results using the electromagnetic calorimeter (EMCal) , transverse energy
distribution, transverse momentum distribution of 7r 0,
and inclusive photon. 1,2) In the early phase of the polarized proton operation, these analyses will be extended to the study of gluon polarization (b..g) in the
proton with pion production,3) which is one of the main
goals of the project.
The data analyses are in progress at the RHIC Computing Facility (RCF) and the PHENIX Computing
Center in Japan (CC-J).4,5) A database management
system has been carefully chosen to ensure identicalreference of calibration constants at both RCF and
CC-J. 6) Large-scale simulation has just been finishedat CC-J and the simulation data is being transferred
to RCF.7)
Towards the full operation of the Muon Arm in 2001 ,the construction and commissioning of Muon detectors
are now at full speed. All Muon Thacking chambers are
installed in the Muon Magnet. Signals are read out
successfully using partially installed electronics, andthe optical alignment system is a key device for achieving 100 j.Lm position resolution and its installation will
be completed with CCD readout system. 8 )The Muon Identifier (MuID) has been installed since
September, 1998. A part of the system was read out
successfully in gold-gold collisions this summer. 9) The
MuID is expected to provide a "road" of penetrating
track as a seed for both level-1 trigger and track reconstruction with Muon Thacking. A road finding algorithm has been developed and applied for the real
events, and performed successfully.10)
The Muon Arm will be able to provide powerfulconstraints on b..g through heavy quark productions l l )even in the first year of polarized proton operation.
Since we are interested in rare events such as lepton or photon productions with high transverse momentum, a level-1 trigger is a key device in pp colli-

sions. The development of such a trigger system forCentral Arms based on the energy deposit in EMCal
is in progress. 12 )In parallel to these efforts in the PHENIX experiment , we prepared for the commissioning of RHIC withpolarized proton beams. The first snake magnet was
already in its place.
The polarized ion source has been replaced withan intense optically pumped polarized ion source(OPPIS).13) It can provide high current (~ 1mA)
and high polarization (~ 80%). After the acceleration
through linac to 200 Me Y, the polarization was typically measured to be rv 70% during the commissioning.
In the Alternating Gradient Synchrotron (AGS), several depolarization resonances have been overcome andthe final polarization was measured to be rv 35%.
The polarization of the proton beam in RHIC has
been measured using a pC CNI polarimeter 14 ) which
was developed last year through experiment E950 at
AGS. 15) In the experiment, the single transverse-spin
asymmetry AN for elastic scattering of proton off carbon was measured as a function of momentum transfer
squared t in the Coulomb Nuclear Interference (CNI)
region (10- 3 ::; -t ::; 10- 2 Gey2). A recoiled Carbon
was clearly identified using both time-of-flight and energy detected in the silicon detector. An analyzing
power of rv 1.5% was found at - t = 0.01 Gey2 andit was sufficiently large to be employed for the RHIC
polarimeter .16)
Prior to the installation of the pC CNI polarimeter,
the silicon detector has been calibrated in terms ofenergy at either at the test bench using an a-source
or at the Tandem Accelerator Facility using a 10 MeY
proton beam. The silicon strips are found to be very
uniform in their response.
We have installed four sets of silicon detectors in the
RHIC ring at azimuthal angles of 45 0 , 135 0 , 225 0 , and
315 0 • This configuration enables us to measure thepolarization vector in the plane normal to the beam.
The polarized beam was injected to RHIC at
24.3 Ge Y I c. With the snake off, we have measured
vertical polarization. Then, we adiabatically turnedon the snake magnet to rotate the spin direction into
the horizontal plane while maintaining the polarization. The polarimeter measured horizontal polarization. With an acceleration of 0.7 GeY I c, we expectedthat the spin direction would be rotated by 180 0 in
the horizontal plane. This expectation has been confirmed using the polarimeter. The polarization wasmaintained up to 29.1 GeY Ic, then lost by further acceleration. Asymmetries are summarized in Fig. 1 as

227

4.0

t;' 3.0

Slr'

•

--6

"1

x

-

B 2.0

-

-

<1)

e

~

<

• snake ono snake off
1.0-----4

0.0
40.0

45.0

50.0

55.0

60.0

65.0

70.0

Gy
Fig. 1. Asymmetries measured at RHIC are plotted as afunction of G"(.

a function of G,,(, where G represents the anomalous
magnetic moment of the proton. This represents thefirst storage and acceleration of polarized proton beamat high energy. 14)
With this success of the polarized proton commissioning, we hope that this project will become very
fruitful including future measurements,17- 19) so thatprecise information on the spin structure of the nucleon will be obtained by a global analysis. 20 )References
1) A. Bazilevsky et al.: RIKEN Accel. Prog. Rep. 34, 232(2001).

2282) H. Torii et al.: RIKEN Accel. Prog. Rep. 34, 238 (2001).
3) Y. Goto et al.: RIKEN Accel. Prog. Rep. 34, 248 (2001).
4) T. Ichihara et al.: RIKEN Accel. Prog. Rep. 34, 252(2001) .
5) Y. Watanabe et al.: RIKEN Accel. Prog. Rep. 34, 254(2001).
6) S. Yokkaichi et al. : RIKEN Accel. Prog. Rep. 34, 256(2001).
7) N. Hayashi et al.: RIKEN Accel. Prog. Rep. 34, 258(2001).
8) J. Murata et al.: RIKEN Accel. Prog. Rep. 34, 237(2001).
9) A. Taketani et al.: RIKEN Accel. Prog. Rep. 34, 230(2001).
10) Y. Mao et al.: RIKEN Accel. Prog. Rep. 34, 242(2001).
11) H. D. Sato et al.: RIKEN Accel. Prog. Rep. 34, 244(2001).
12) D. Galanakis et al.: RIKEN Accel. Prog. Rep. 34, 240(2001) .
13) Y. Mori et al.: Rev. Sci. Instrum. 71 , 1237 (2000).
14) K. Kurita et al.: RIKEN Accel. Prog. Rep. 34, 229(2001).
15) I. Alekseev et al. : RIKEN Accel. Prog. Rep . 33, 170(2000) .
16) J. Tojo et al.: RIKEN Accel. Prog. Rep. 34, 236 (2001).
17) D. Boer et al.: RIKEN Accel. Prog. Rep. 34, 249(2001).
18) A. Deshpande et al.: RIKEN Accel. Prog. Rep. 34, 251(2001).
19) J. Murata et al.: RIKEN Accel. Prog. Rep. 34, 237(2001) .
20) H. Kobayashi et al.: RIKEN Accel. Prog. Rep. 34,248(2001).

RIKEN Accel. Prog. Rep. 34 (2001)

The First RHIC Polarimeter Commissioning
K. Kurita, H. Spinka,*1 D. Underwood,*1 H. Huang,*2 W. Glenn,*2 Z. Li *2 W. MacKay *2 G. Mahler *2 .
Y. Makdisi,*2;V' McGahern,*2 S. Rescia,*2 T. Roser,*2 T. RuSSO,*2 G. Bunce, G. Igo,*3'w. Lozowski:*4
1. Alekseev,*. V. Kanave~s , *5 D. Svirida,*5 H. En'yo,*6 K. Imai,*6 J. Tojo,*6 A. Deshpande, Y. Goto,
M. IshIhara, T . Ichlhara, N. Saito, A. Taketani, Y. Watanabe, D. Fields,*7 D. Koehler,*7
D. Brown,*8 S. Dhawan,*9 V . Hughes,*9 and R. Krisst*9
The most critical question for our spin experimentswith the Relativistic Heavy Ion Collider (RHIC) is
whether it is possible to accelerate polarized protons
in RHIC. We finally came to the point of injecting thepolarized proton beam into RHIC for the first timein September 2000, after a very long period of hard
work. I- 3)
We will describe in this article our achievements during the two weeks of the polarized proton accelerationcommissioning.
It should be noted that we are still in the construction phase and that some necessary equipment waspartially instrumented at the commissioning. We had
one pC CNI polarimeter to measure the polarizationof the beam and a set of helical dipole magnets calleda Siberian Snake in a RHIC ring. Two sets of snake
magnets are needed to accelerate polarized protons up
to the RHIC full energy of 250 GeV, but it was known
that one was sufficient to reach 100 GeV if the orbital
error is minimal although the stable spin direction becomes horizontal instead of vertical.
Our goals for the commissioning were:(1) to establish the asymmetry measurement,(2) to observe the polarization direction change (vertical to horizontal) when the snake is turned on,(3) to accelerate the polarized proton beams, and(4) to achieve high polarization at 100 GeV.
The first step was to establish asymmetry measurement with the pC CNI polarimeter by identifying recoilcarbons from pC elastic scatterings. The commissioning showed that we can identify pC CNI scattering
very clearly, with little background. When the data
were combined to measure the vertical polarization, we
verified the vertical polarization of the injected beam
(Fig. 1 (a)). We reversed the polarization and observed
it in reverse (Fig. 1 (b)) . We turned off the polarization
at the source and observed zero (Fig. 1 (c)) . On thebasis of these results, we confirmed that the polarimeter was working and we had achieved a polarized beam
in RHIC.
We also observed the expected horizontal polar*1
*2

*3
*4

*5
*6
*7
*8

*9

Argonne National Laboratory, USA
Brookhaven National Laboratory, USA
University of California, Los Angels, USA
Indiana University, USA
Institute of Theoretical and Experimental Physics, Russia
Kyoto University
University of New Mexico, USA
New Mexico State University, USA
Yale University, USA' '''.00>42''0.oooe,(a),,_11•.4+_ 5.9

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0,002

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-0.0"

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Vertical Pol.

-0.0 '

Flipped Pol.

-O.o..o.OM.ooe.OM.0020 0.00I,00..ooo.oom.01

Zero Pol.

Fig. 1. Polarization vector obtained by the RHIC polarimeter during the establishment of the vertical polarization.

:~,"0."""·0.000"( a)72+- '"

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77:~";" (c)

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Snake on at Injection.o~;~:;~;o~~:~;::~,~ '.

~0.002-.;:;;~:;;;:;";tFig. 2. Study of Snake magnet behavior.

ization after we adiabatically turned on the Siberian
Snake (in the case of using only one snake, it is necessary to turn it on after injecting the beam) (Fig. 2).
We accelerated the beam to cause the polarization toreverse radially and it did, and then we repeated thiswith the Siberian Snake off and observed no remaining polarization after the same acceleration. This confirmed that we can accelerate polarized protons with
the Siberian Snake.
We further accelerated the proton beam up to approximately 32 GeV without appreciable depolarization. However , we were not successful in achieving
higher acceleration. We believe that this is due to thelarge orbit errors which may induce unexpected depolarization resonances. Further study beyond our third
goal, including the orbit error correction, will be undertaken during the next RHIC spin run.
This was the first time we observed a polarized proton beam in RHIC and it was a significant milestone
for RHIC spin physics. We were greatly encouragedby this commissioning although many challenges still
remain .
References
1) J. Tojo et al.: RIKEN Accel. Prog. Rep . 32, 52 (1999);
34, 236 (2001) .
.
2) I. Alekseev et al.: RIKEN Accel. Prog. Rep. 33, 170(2000).
3) K. Kurita et al.: RIKEN Accel. Prog. Rep . .34, 234(2001) .

229

RIKEN Accel. Prog. Rep. 34 (2001)

First Commissioning of the PHENIX Muon Identifier
by Au-Au Collision
A. Taketani, V. Cianciolo,*l H. En'yo,*2 N. Hayashi, T. Ichihara, K. Imai,*2 M. Ishihara, L. Kotchenda,*3
K. Kurita, Y. Mao,*4 J. Newby,*5 K. Pope,*5 K. Read ,*l,*5 N. Saito,
H. D. Sato,*2 and T.-A. Shibata*6
The muon identifier (MuID) of the PHENIX experiment was installed in 1998 and has been tested. We integrate MuID detector panels, gas supply, readout electronics, a data acquisition system, high-voltage power
supply, online monitoring, and an off-line reconstruction program. The MuID data was collected during
the Au-Au colliding beam run in the year 2000 as wellas other subsystems of the PHENIX.
The MuID detector is expected to play an importantrole with the Muon Tracker l ) (MuTR) in the RHIC
spin program 2) as well as in the heavy-ion program.
The MuID can identify muons from other hadron particles by the sandwiching of five absorber steel plates
and proportional tubes. 3) It also functions as a trigger
counter and can find course tracks for the more accurate tracking of the muon trajectory at MuTR. The
MuID covers 10 to 35 degrees in () and 360 degrees in ¢at 7 meters from the interaction point. We segmented
a total of 10 gaps. Each gap has four large-sized andtwo small-sized panels. The detectors are located at
the forward and backward regions, the so-called south
and north arms, respectively. Each panel has horizontally and vertically oriented tubes. The MuID panels
were fabricated 4 ) and installed. 5,6)
At the time of the commissioning, the muon south
magnet (MMS) had not yet been installed between thecentral magnet and the MuID. Therefore, the secondary particles which were generated at the beam
pipe were not shielded well. Due to limitations of theavailable readout electronics, seven small-sized panels
at the south arm were prepared for operation. We connected all gas tubing to the gas supply system 7) and fed
pure CO 2 instead of a CO 2 and i-C6HlO mixture. The
pure CO 2 has less gas amplification gain and slower
drift velocity. However, the beam crossing time of thisrun is sufficiently long to utilize slower drift velocity
and the noise level is suffciently low compared with thesignal threshold level, as described later. The flow rate
was 3.5 liters per minute, corresponding to one volume exchange per day. In addition, the high-voltage(HV) cables and low-voltage (LV) supply lines wereconnected between the seven panels and each power
supply. A signal cable can handle up to 16 channels of
*1
*2
*3

*4

*5

*6

230

Oak Ridge National Laboratory, USA
Kyoto University
State Interphysica, Russia
Chinese Institute for Atomic Energy, China
University of Tennessee, USA
Tokyo Institute of Technology

the chamber signal. The small-sized panel has two cables for horizontal orientation and one cable for verticalorientation. Due to the radiation safety issue, all gas
tubing and electronics cables of the small-sized panels
are located at a place where frequent access is not expected. However, our readout electronics are locatedat a place which has relatively easy access. Thus, we
decided to operate gas, HV, and LV, regardless of thesignal cable connection. However, we chose which signal cable(s) was connected to the readout electronics
each time.
After establishing the connection, the internal
preamps were checked by feeding the test pulser signal.
It was amplified by the preamp and checked at the signal cable end using an oscilloscope. All preamps of theseven panels were operational.
After five volume gas exchanges, we started to apply a HV up to 4.2 kV. A HV monitoring program andan automatic voltage control program were developed.
The monitoring program displays each HV operation
status every 30 seconds. Forty-eight channels of HV
can be checked at a glance. The control program monitors the current during ramping. Voltage is increased
when the associated current does not exceed the specified threshold, which is typically 6/-LA at 4 kV. It takes
15 min to reach a 4.2 kV operational voltage.
During the applying 4.2 kV, the noise level of eachsignal was measured as 40 m V on average, as expected.
During the first week of MuID operation with a
65 GeV / A Au-Au collision beam, one signal cable wasconnected to the readout electronics. The signal channels which are at the first gap, horizontal, and closest to the beam were chosen as the highest rate channels for timing tuning purposes. The coincidence of
forward-backward beam-beam counters were used fortriggers. Figure 1 shows the hit occupancy rate perchannel per event. The solid line and plus markers
represent the measured value and simulated data, respectively. The simulated data includes HIJING event
generation and the detailed detector simulation. The
measured and simulated values are matched. We expect that the hit occupancy rate will be reduced toless than 0.1 when the MMS and beam collar are installed. The beam collar will shield the bare beam
pipe between the MMS and the MuID and reduce theexposure of secondary particles.
During the last two weeks of the gold-gold collision
run, six signal cables were connected to the readout
electronics. Horizontal and vertical cables were cho-

o

2

468

10

12

14

channelFig. 1. Hit occupancy rate.

sen from the second, third, and fifth gaps. Each horizontal and vertical readout channel is lined since it
is a requirement for course road finding in the reconstruction program. Mao et al. reported details of thereconstruction. 8 ) We confirmed the reconstructed roadin the event display. The 550 k events are recorded into
the tape as part of the PHENIX main data stream.
Figure 2 shows the coincidence between the MuID hit
multiplicity and the beam-beam counter (BBC) hit
multiplicity. It has a clear positive correlation, as expected, since the beam-beam counter covers 3 :S I TJ I:S
4 and the MuID covers 1.1 :S I TJ I:S 2.4.
The integration and operation of the partial MuID
system was carried out and the commissioning was successfully finished with the Au-Au collision run. We willcontinue to prepare for the upcoming polarized proton

Fig. 2. Multiplicity coincidence.

run in 2001.
References
1) J. Murata et al.: RIKEN Accel. Prog. Rep. 33, 165(2000).
2) H. En'yo et al.: RIKEN Accel. Prog. Rep. 30, 34 (1997).
3) Y. Mao et al.: RIKEN Accel. Prog. Rep. 30, 36 (1997).
4) A. Taketani et al.: RIKEN Accel. Prog. Rep. 31 , 172(1998) .
5) A. Taketani et al.: RIKEN Accel. Prog. Rep. 32, 50(1999) .
6) K. Kurita et al.: RIKEN Accel. Prog. Rep. 32, 32(1999).
7) A. Taketani et al.: RIKEN Accel. Prog. Rep. 33, 33(2000).
8) Y. Mao et al.: RIKEN Accel. Prog. Rep. 34, 242 (2001).

231

RIKEN Accel. Prog. Rep. 34 (2001)

PHENIX EMCal: First Results from RHIC Au-Au Collisions
A. Bazilevsky, G. David,*l H. En 'yo,*2 Y. Goto, K . Imai,*2 E. Kistenev,*l N. Saito, and H. Torii*2
for the PHENIX Collaboration
PHENIX 1) is one of the two large experiments at
the BNL relativistic heavy-ion collider (RHIC). The
PHENIX detector is suitable for broad research programs in both heavy-ion and polarized proton collisions. From June 2000, RHIC produced collisionsof gold ions at beam energies up to 65 GeV per nucleon. Luminosities of about 5 x 10 25 cm- 2sec- 1 wereachieved.
The electromagnetic calorimeter (EM Cal) of
PHENIX showed excellent performance during the2000 run. Preliminary physics results include transverse energy measurements , and inclusive-photon and?To spectra reconstruction. Below we present theseresults .
Transverse energy is one of the key 0 bservables inquark-gluon plasma (QGP) search and study. According to Bjorken,2) the transverse energy rapidity density dET I dy is directly related to the spatial energy
density E in a relativistic collision. Many simulation
studies based on the HIJING 1.33 event generator 3 )and G EANT4) detector response were performed todetermine the relationship between the measured and"true" ET distribution. The obtained ET distribution at mid-rapidity is shown in Fig. 1. Two percentof the most central Au-Au collisions gives a mean ET
value of about 550 GeV ± 10% (syst) in a pseudorapidity unit (statistical error is negligible), which is about
40% higher than that obtained in the SPS-NA49 fixedtarget experiment for Pb+Pb collisions. 5)
One of the proposed signatures of the QGP is theenhancement of photon radiation. Compton scattering of the gluons enhances the yield of photons at
Pt > 2 GeV Ie. Thermal radiation from the hot QGP
gas enhances it at lower Pt « 2 GeV Ie). The dominant source of background for direct photons is ?To
decays; therefore, ?To measurements are very important for direct photon reconstruction. Reconstruction
of ?To is also important for studying the jet quenchingeffect, and isospin correlations and fluctuations. The?To peak can be clearly identified in the two-cluster invariant mass distribution.6 ) After applying the back-

PHENIX PRELIMINARY

i . . ..

10- :-,'. . . . .+., .

j~

10 - 5

0.5

I

I

I

I

I

I

I

I

1

1.5

2

2.5

3

3.5

4

4.5

pT

5

[GeV/ c]Fig. 2. 71'0 Pt spectrum.

AlII
Nol}-photonePl'ftftOns

Fig. 1. E t distribution in Au-Au collisions at
130GeV IA.
*1

*2

232

Brookhaven National Laboratory, USA
Kyot o University•

VB =Fig. 3. Inclusive-photon Pt spectrum; solid: all EMCal
clusters, dotted: clusters suppressed by EMCal time offlight or shower profile cuts for photons, dashed: clusters surviving EMCal time of flight and shower profile
cuts for photons.

ground subtraction technique, and acceptance and efficiency corrections,7) the 7r 0 Pt spectrum was obtained(Fig. 2). The slope parameter of the exponential fit
was estimated to be 303 ± 11 (stat) ± 67 (syst ) MeV I e,
which is higher than that obtained in the SPS-WA98
experiment for central Pb+ Pb collisions: 8 ) 200 MeV I e
for low Pt (~ 1 GeV Ie) and 270 MeV Ie for higher
Pt (~ 3 GeV Ie). Figure 3 shows the reconstructed
inclusive-photon spectrum in EMCal. To identify photons in EMCal, we applied time-of-flight and shower
profile cuts. This helps reduce the non-photon background by a factor of 2 to 20 depending on the energy
region. The residual contamination varies from 30%
for Pt = 0.7 GeV Ie to < 15% for Pt > 2.5 GeV Ie (sim-ulation study). The efficiency of photon reconstruction
after these cuts was about 90%.
References
1) D. P. Morrison: Nucl. Phys. A 638, 565c (1998).
2) J. D. Bjorken: Phys. Rev. D 27, 140 (1983).
3) X. N. Wang and M. Gyulassy: Phys. Rev. D 44, 3501
(1991).
4) GEANT 3.2.1, CERN Program Library (1993).
5) T. Alber et al.: Phys. Rev. Lett. 75, 3814 (1995).
6) H. Torii et al.: RIKEN Accel. Prog. Rep. 34, 238 (2001).
7) T. Sakaguchi et al.: RIKEN Accel. Prog. Rep. 34, 261(2001).
8) M. M. Aggarwal et al.: nucl-ex/0006007; Phys. Rev. C,
to be published.

233

RIKEN Accel. Prog. Rep. 34 (2001)

RHIC pC CNI Polarimeter
K. Kurita, H. Spinka,*l D. Underwood,*l H. Huang,*2 W. Glenn,*2 Z. Li,*2 W. MacKay,*2 G. Mahler,*2
Y. Makdisi,*2 W. McGahern,*2 S. Rescia,*2 T. Roser,*2 T. RuSSO,*2 G. Bunce, G. Igo,*3 W. Lozowski,*4
I. Alekseev,*5 V. Kanavets,*5 D. Svirida,*5 H. En'yo,*6 K. Imai,*6 J. Tojo,*6 A. Deshpande, Y. Goto,
M. Ishihara, T. Ichihara, N. Saito, A. Taketani, Y. Watanabe, D. Fields,*7 D. Koehler,*7
D. Brown,*8 S. Dhawan,*9 V. Hughes,*9 and R. Krisst*9
A number of possible methods of measuring the polarization at RHIC were considered. The problem isthat the process used for low-energy protons, pp elastic
scattering at -t = 0.15 (GeV /c)2, appears to have diminishing analyzing power of l/energy. Therefore, its
analyzing power is significantly small for polarimetryat RHIC energies . One new attractive approach uses
the asymmetry of inclusive pion production at large XF
and moderate Pr. Such a polarimeter was designed,
but was abandoned due to its high cost (roughly $1.5
million).
To use pC elastic scattering in the Coulomb nuclear
interference (CNI) region was a novel suggestion. CNI
involves scattering from the anomalous magnetic moment of the polarized proton, an electromagnetic spinflip amplitude, and a nonflip hadronic amplitude. Thismethod is attractive because(1) a significant (4%) analyzing power is predicted
over the entire RHIC range, 1)(2) the figure of merit is high due to its large crosssection,(3) a very thin solid carbon target allows us easy target handling and quick measurements in RHIC,
and(4) it allows inexpensive setup when only the recoilcarbons are detected by Si detectors in vacuum.
In the course of the development of the RHIC pC
CNI polarimeter, AGS-E950 was performed to measure the analyzing power of pC CNI reaction at the
RHIC injection energy.2,3) It was found that statistically significant polarization measurements can be performed with pC CNI. According to our experiencefrom performing AGS-E950, the RHIC pC CNI polarimeter was designed to enable the use of the same
principle. However , the following RHIC specific issues
were considered and new improvements were reflectedin the design.
(1) Smooth impedance change is required inside thepolarimeter chamber so as not to disturb thebeam.
(2) At RHIC full luminosity with 250 GeV beam,
*1
*2
*3
*4

*5
*6
*7

*8
*9

234

Argonne National Laboratory, USA
Brookhaven National Laboratory, USA
University of California, Los Angels, USA
Indiana University, USA
Institute of Theoretical and Experimental Physics, Russia
Kyoto University
University of New Mexico, USA
New Mexico State University, USA
Yale University, USA

the temperature of the target may become significantly high.
(3) Computer simulation of spin orientation dynamics implies that protons far away from the centerof the beam might be depolarized.
(4) RHIC requires ultrahigh vacuum in the range of10- 9- 10- 10 Torr and electronics are not allowedin the vacuum.
(5) Up to 250°C baking is required.
(6) To minimize the noise, the distance between the
Si detector and the preamplifier has to be small.
(7) A significantly high data-taking rate is required.
Figure 1 shows the RHI C polarimeter installed in
one of the RHIC rings (the blue ring). As evident in
the photograph, the entrance and exit of the chamber
have conical shapes to reduce impedance gap. Resonance peaks in the electromagnetic wave frequency
space in the chamber were measured and were foundto be sufficiently weak.
The very thin target was made available throughdevelopment at IUCF. Its thickness, only ioo atoms,
allows the slow carbon (iOO KeV) to escape, thus reducing the scattering rate to a level which can be tolerated by detectors; the target survives beam heating
due to its large surface-to-volume ratio. To determine
the radial polarization distribution, two target position
remote control systems were designed to allow horizontal and vertical scans of the beam. Four Si detectors
were placed at 45-degree positions so that none of thedetectors fall in the shadow of the target frames. A
schematic view of the Si detector arrangement is shownin Fig. 2. In addition to the four Si detector ports, two
Si ports were installed in a 90-degree location to allow abetter asymmetry measurement for the vertically polarized proton beam because 45-degree detectors candetect only 1/ y'2 of the analyzing power of the pC
CNI process.

Fig. 1. RHIC pC CNI polarimeter installed in RHIC.

Carbon microribbon
target (5~g/c:m2)

Up

Si #1

500

right

left

400

Si #2
500

Fig. 4. Arrival time versus pulse heightof events in a Si strip.

Beam's View

Fig. 2. Schematic diagram of RHIC
pC CNI polarimeter as viewed by
the beam.

1000

Fig. 3. Typical recoil carbon signal
from Si detector recorded by our
prototype WFD.

Only metals and ceramics are allowed to be usedin ultrahigh vacuum on the order of 10- 9 - 10- 10 Torr.
Also, the baking requirement excludes the possibilityof installing preamplifiers in the vacuum. However, Si
detectors have to be in the vacuum to measure verylow-energy recoil carbons because these carbons lose
energy very rapidly in any material. It is a well-known
fact that the distance between the detector and thepreamplifiers has to be minimized. Therefore, we designed a Si-mounting plate, which is made of ceramics
and preamlifier cards, which can be mounted directlyon the atmospheric pressure side of the feedthrough.
With this design, we can remove preamplifier cards
without breaking the good vacuuum. Then, the baking can be performed very efficiently.
A potential disadvantage of using very thin carbon
target is that the number of carbon atoms can actually become depleted, so that it is important to use thescattering time efficiently. However, this also works out
well for an expected lifetime of two to three hours of
the beam, and for measurements taking less than ten
seconds when the RHIC reaches the full-design luminosity. It is also important to use the scattering time
efficiently to measure the polarization many times during proton injection into RHIC without significantly
increasing the beam emittance (and decreasing the collision luminosity).
Although currently our main data aquisition (DAQ)
system is based on CAMAC FERA modules which
limit our data-taking rate, we have developed a prototype wave form digitizer (WFD) which can in principle
be made to work without a dead time. This prototype
was tested in the RHIC spin-commissioning period in
September 2000 4 ) and was found to work successfullyin the RHIC environment. Figure 3 shows a typicalrecoil carbon signal from the Si detector. A rapid data
readout scheme is to be developed next year. WFD
also works efficiently in reducing the systematic errors
by distinguishing overlapping events from nonoverlapping events.
When we performed RHIC spin-commissioning, we
injected only six bunches instead of 120 to allow ourDAQ system to work without significant dead time.

A=O.OC289+ -0.00030'fJ =84.4+- 5.9

0.01
0.008
0.006
0.004
0.002

-0.002- 0.004-0 006-0.008- 0.01I-0.(}·W.09S.09 S .0941. 0020 o.ooa.oO G.oOG.OoroOl

Fig. 5. The first polarization vector measurement (10 sigma
effect) with the RHIC pC CNI polarimeter.

The polarization direction was alternated so that we
can obtain asymmetry with significantly less systematic errors, which mainly come from the detector acceptance and bunch-by-bunch luminosity variations.
Since the Si detectors are located 15 cm from the target, the carbon atoms of interest arrive 60- 80 nanoseconds after a bunch passes the target. The signal is 0 bserved after prompt products are gone, and before thearrival of the next bunch. (At full luminosity, RHIC
bunch spacing is 106 nanosecconds.) The carbon band,
along with the alpha band , was clearly observed in thearrival time versus pulse height scatter plot shown in
Fig. 4. After the carbons were identified in the carbon
band , the asymmetry in the horizontal and vertical directions was calculated. Figure 5 shows the first significant polarization vector measured while we were trying
to establish the polarization measurement in RHIC.
References
1) T. D. Lee: Proc. Workshop on Hadron Spin-Flip at
RHIC Energies, RIKEN BNL Research Center, 1997July-Aug., Vol.3 (1997).
2) J. Tojo et al.: RIKEN Accel. Prog. Rep. 32 , 52 (1999);
34, 236 (2001).
3) I. Alekseev et al.: RIKEN Accel. Prog. Rep. 33, 170(2000) .
4) K. Kurita et al.: RIKEN Accel. Prog. Rep. 34, 229(2001).

235

RIKEN Accel. Prog. Rep. 34 (2001)

Measurement of the Analyzing Power for Proton-Carbon Elastic
Scattering in the Coulomb-Nuclear Interference Region at 22 GeV Ie
J. Tojo,*l 1. Alekseev,*2 M. Bai,*3 B. Bassalleck,*4 G. Bunce, A. Deshpande, J. Doskow,*5 S. Eilerts,*4
D. E. Fields,*4 Y. Goto, H. Huang,*3 V. Hughes,*6 K. Imai,*l M. Ishihara, V. P. Kanavets,*2 K. Kurita,
K. Kwiatkowski,*5 B. Lewis,*4 W. Lozowski,*5 Y. Makdisi,*3 H. O. Meyer,*5 B. V. Morozov,*2 M. Nakamura,*l
B. V. Przewoski,*5 T. Rinkel,*5 T. Roser,*3 A. Rusek,*3 N. Saito, B. Smith,*4 D. N. Svirida,*2 M. Syphers,*3
A. Taketani, T. L. Thomas,*4 D. Underwood,*7 D. Wolfe,*4 K. Yamamoto,*l and L. ZhU*l
Measurement of the analyzing power for protoncarbon (pC) elastic scattering in the Coulomb-nuclear
interference (CNI) region provides a unique opportunity to study spin dependence of hadronic interaction and an application to high-energy proton polarimetry at BNL-RHI C as the first polarized proton
collider. 1- 3) The analyzing power AN(t) originatingfrom interference between electromagnetic (EM) spinflip interaction and hadronic spin-nonflip interactionis theoretically predicted,4-6) ranging from 1-4 % in
the small momentum transfer region of 10- 3 < -t <10- 2 (GeV jc)2.
Experiment E950 involving the first measurementof the AN(t) was carried out at BNL-AGS in March
1999. The pC elastic scattering from a 21.7 GeV j cpolarized proton beam and an ultrathin carbon target
was identified by detecting only recoil carbons emitted
almost 90° to the beam direction, which had a very
low energy ranging from 100 ke V to a few MeV. The
experimental setup to measure the energy and the timeof flight (TOF) of recoil carbons consisted of two leftright detector arms of silicon strip detectors (SSDs)
and microchannel plate assemblies (MCP) with thincarbon foils. The details of the experimental setup
and the performance are described in detail in Refs. 1
and 2. In this article, we report the preliminary resultsof the analyzing power measurement.
Recoil carbon events were selected by making use of
kinematic relation between energy and TOF. Physics
backgrounds of 4.4 MeV C* excitation and Ll production were not kinematically allowed to come into thedetector acceptance. Other backgrounds were estimated to be less than 3% from target-empty data. Momentum transfer squared - t was determined kinematically from both energy and TO F. Energy loss of recoilcarbons at the carbon target, the thin carbon foil andthe dead layer of the SSDs were estimated and corrected to determine - t. The AN(t) was derived using

*1
*2

*3
*4

*5
*6
*7

236

Department of Physics, Kyoto University
Institute of Theoretical and Experimental Physics, Russia
Brookhaven National Laboratory, USA
Department of Physics and Astronomy, University of New
Mexico, USA
Indiana University Cyclotron Facility, USA
Department of Physics, Yale University, USA
Argonne National Laboratory, USA

0.03 .----- -- -- - - - - - -~- ----,

Preliminary

0.025 r-~ 0.02 r0..

gp 0.015.~ 0.01~ 0.005-<+o ~-I--I--I--I--I---I-~~~

o

0.005

0.01

0.015

0.02

0'l.025

0.03

0.035

0.04

-t(GeV/c)

Fig. 1. Preliminary results of the analyzing power AN asa function of momentum transfer -to The error bars
indicate statistical errors only.

a square root formula:AN(t) = -1 / Nl(t) . Nk(t) - / Ni(t) . Nk(t). (1)P B / Nl(t) . Nk(t) + / Ni(t) . Nk(t)Nl(t) (Nk(t)) represents the number of recoil carbon
events at -t , which were detected in the right (left)
detector arm with beam polarization up (down). P B
represents the beam polarization. It was measured independently and found to be approximately 40%. The
preliminary results of AN(t) are shown in Fig. 1. Error
bars indicate statistical errors only. Systematic errors
are still under study.
In summary, we succeeded in measuring the analyzing power for pC elastic scattering in the CNI region
with high statistical accuracy. The preliminary results
were presented. Our data will be compared with atheory including the contribution of hadronic spin-flip
amplitude. Hadronic spin-flip amplitude will be constrained from the further analysis.
References
1) J. Tojo et al.: RIKEN Accel. Prog. Rep. 32,52 (1999).
2) I. Alekseev et al.: RIKEN Accel. Prog. Rep. 33, 170(2000).
3) K. Kurita et al.: RIKEN Accel. Prog. Rep. 34, 234(2001).
4) T. D. Lee: Proc. Workshop on Hadron Spin-Flip at
RHIC Energies, Vol. 3, 1997-July-Aug., (RIKEN BNL
Research Center 1997).
5) B. Z. Kopeliovich: hep-ph/9801414.
6) N. H. Buttimore: AlP Conf. Proc. , 95, p.634 (1983).

RI KEN Accel. Prog. Rep. 34 (2001)

Construction of PHENIX South Muon Tracker
J. Murata, M .. L. Brooks, *1. D. S.*~rown,*2 N ..Bruner,*3 D. Fields,*3 H. Kobayashi, D. M. Lee,*1 S. Pate,*2
N. SaIto, T.-A. ShIbata, W. Sondhelm,*1 R. Towell,*1, M. Sugioka,*4 and C. Velissaris*2
Mechanical installation of the PHENIX south muontracker (MuTr) is now close to completion. The southmuon arm was installed in the PHENIX experimental hall by the end of 2000, after completion of thefront-end electronics (FEE) installation. In July 2000,
all cathode strip chambers, each consisting of threestations (#1, 2, 3) which were mainly constructedby the BNL, LANL and UNM staff, were installed
into the south muon magnet. The RIKEN team was
responsible for the chamber gas supply system andthe optical alignment system, which were constructed
and installed. 1) Before the chamber installation, the
RIKEN team also performed a resolution measurementof a test chamber using a prototype FEE at LANL in
1999, obtaining ()" = 165p,m which was determined bya simple center-of-gravity method. By using the actual PHENIX FEE with the actual #2 chamber, we
obtained a sufficient resolution of 100 p,m by a chargeratio method in the summer of 2000. The main reason
for the improvement is the difference in the position
determination method.
Although we have confirmed the sufficient quality of
the chamber and the FEE, an optical alignment system is required which monitors accurate chamber geometries in order to obtain the required momentum
resolution in the actual PHENIX system. This system
consists of a (62.5/125)-p,m-diameter fiber optics cable
at #1, a 1-cm-diameter convex lens at #2 , and a CCD
camera with a 8.8 x 6.6 mm (768 x 493 pixels) effective
region at #3. There are 56 such optic beams monitoring the relative X- Y positions between the threestations. Because the mechanical precision required
for each optics component must be within 25p,m, thelens and optics fiber are aligned to the center of mounting blocks with accuracy of 10 p,m by means of a special optical system. The position offsets of the CCD
cameras from the centers of the mounting blocks were
measured after tuning the camera position in order toobtain the focal image in the actual system. All optics
components were installed inside the muon magnet by
the end of 2000.
A data acquisition system for CCD image capturing has also been constructed. The 56 camera signals are fed into a video-signal switching box (Keithley
7001+7011S) ,2) which has one output port connected
to a frame-grabbing card (Scion Corp. , Pr-LG3)3) onan image-capturing PC. The digital I/O ports of the
Pr-LG3 control the switching of the 56 channels. We* 1 Los Alamos National Laboratory, USA*2 New Mexico State University, USA*3

University of New Mexico, USA

Fig. 1. Installing lens blocks on #2 chambers. The upper
half of the PHENIX south muon magnet is shown.

can control image capturing and also external I/O using the single software, Scion Image for Windows. 3 )This simplicity has huge advantage in terms of the stability of such digital systems which undergo frequentinterruption. The same macroscript also calculates thecenter position of the focal image and stores this in an
output file which is connected to the database.
We have also constructed the chamber gas supply
system. 4) The requirements of the gas system are: (1)usage of 50%Ar+30%C0 2 +20%CF 4 mixed gas, which
was selected mainly for its non-flammability and relatively small Lorentz angle; (2) full recirculation inorder to conserve the expensive CF 4 gas; and (3) stable pressure control that protects the thin #2 chamber windows. In order to satisfy these requirements,
we have designed and built a gas system which consists of the main control rack, a compressor panel anda distribution panel. The construction of each system
is almost completed. Following a system check andconstruction of the electric read-out system, the alarmsystem is now under construction.
In addition to these works, the RIKEN team is also
going to contribute to the MuTr software and FEE
development. The construction of MuTr chambers for
the PHENIX north muon arm has just started, and it
is expected to be completed in 2001.
References
1) J. Murata et al.: RIKEN Accel. Prog. Rep. 33, 165(2000) .
2) Keithley Instruments, Inc.: http://www.keithley.com
3) Scion Corporation: http://www.scioncorp.com
4) PHENIX
MuTr
Gas
SystemHome
Page:
http:// spin.riken. bnl.gov / - jiro /mutrgas.html*4 Tokyo Institute of Technology

237

RIKEN Accel. Prog. Rep. 34 (2001)

Performance of the PHENIX EMCal in First Physics Run
H. Torii,*l A. Bazilevsky, G. David,*2 H. En'yo,*l Y. Goto, K. Imai,*lE. Kistenev,*2 and N. Saito, for the PHENIX Collaboration
In the early summer of 2000, the PHENIX experiment for heavy-ion physics at RHIC has started, andwe will start that for spin physics in 2001. In thisexperiment, the electromagnetic calorimeter (EMCal)
plays an important role in detecting photons and electrons/positrons. In order to cover topics in both
physics, e.g., thermal photon measurement in heavyion physics, and prompt photon, nO and weak boson measurement in spin physics, the EMCal needs tocover a wide energy range from a few hundred MeV to
80 Ge V. Spin physics also requires the energy measurement to be within 2% accuracy to measure cross sections of prompt photons and nO production with 10%
errors, because the cross sections have steep transverse
momentum (PT) slopes. The PHENIX EMCal consistsof a lead scintillator (PbSc) and lead glass (PbGI). In
this paper , we will report only the performance of the
PbSc.
To fulfill the physics requirement, several beam tests
at BNL/ AGS and CERN/SPS 1 ,2) were performed.
From the beam tests, the energy resolution for PbSc
is known as (JE/E = 1.9% EB 8.2%/vE from 0.5 GeV/c
to 80 GeV / c, where EB represents the quadratic sum.
We obtained the energy measurement with 2% accuracy from 0.5 GeV to 80 GeV. This result is consistent with the expected results based on the uncertainty
of beam momentum, nonlinearity of photon multipliertube,3) readout electronics, and shower leakage effect.
At 10 GeV, the result shows 4% deviation, which will
be corrected in the future.
Before the physics experiment of 2000, the energy
scale for all towers was calibrated using a cosmic
muon traversing PbSc module, whose energy deposit
is 38 MeV in average. Figure 1 shows the energy
distribution using the PHENIX clustering algorithm
at Vs = 130 A GeV Au+Au collision. We observed
clearly the minimum ionization peak (MIP) by charged
hadron. The MIP energy was adjusted in each of the
144 towers of PbSc. After this adjustment, a 2% deviation was observed in a relative energy scale. The timedependence measured by the MIP energy was also corrected.
Figure 2 shows the two-photon invariant-mass spectrum with a nO peak after MIP correction. The peakexhibits a nominal nO mass within the 2% statisticalerror. We can conclude that the absolute energy scale
has 2% accuracy.
Table 1 shows the summary of performance. It appears to fulfill the physics requirement of 2% accuracy.

00

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0.45

0.5

Fig. 1.
Preliminary energy distribution by PHENIX
Au+Au collision at y's = 130 A GeV.

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0.45

0.5

GaV

Fig. 2. Preliminary two photon invariant mass distributionin PHENIX Au+Au collision at y's = 130AGeV.

Table 1. Summary of the performance of PHENIX EMCal.
Energy scale
Time dependence
Relative
Absolute

0.4% (after 7% correction)
2% (after < 6% correction)
2%

However, these performance tests are dominated byenergy clusters with less than 1 GeV because of the
280 MeV MIP energy and the steep PT spectrum of nO.
We plan to increase the statistics in the future, and determine the performance up to more than 10 GeV tosatisfy the physics requirement. The physics analysis
is in progress and results 4 ) will soon be available.
References

*1
*2

238

Kyoto University
Brookhaven National Laboratory, USA

1) Y. Goto et al.: RIKEN Accel. Prog. Rep. 32 , 47 (1999).
2) H. Torii et al.: RIKEN Accel. Prog. Rep. 33, 168 (2000).

3) G. David et al.: IEEE Trans. Nucl. Sci. 42, 306 (1995).
4) A. Bazilevsky et al.: RIKEN Accel. Prog. Rep. 34, 232(2001).

239

RIKEN Accel. Prog. Rep. 34 (2001)

Development of a Level-l Trigger for the
PHENIX Central Detector Arms
D. Galanakis,*l Y. Akiba,*2 K. Shigaki,*2 H. Sato,*3 J. Tojo,*3 V. Cianciolo,*4 P. Stankus,*4 A. Wintenberg,*4
G. Young,*4 B. Lillie,*5 G. Bunce, Y. Goto, M. Grosse Perdekamp, N. Hayashi, M. Ishihara, N. Saito,
H. Hamagaki,*6 T. Matsumoto,*6 K. Oyama,*6 K. Barish,*7 M. Bick,*7
B. Nandi,*7 W. Xie,*7 and M. Tamai*8
The PHENIX detector is a large multipurpose
detector at the Relativistic Heavy-Ion Collider at
Brookhaven National Laboratory.!) It consists of two
spectrometers for muon detection 1.2 < TJ < 2.4 andtwo central detector arms ITJI < 0.35 for high resolution detection of electrons, photons and soft hadrons.
The design of the PHENIX apparatus was initially optimized for the needs of heavy-ion physics. However,the detector is also being adapted to perform well inan environment of high-luminosity proton-proton collisions. This upgrade is required for the physics programwith polarized protons including measurements of thegluon-, quark- and antiquark-polarizations inside theproton.
In this paper, we discuss event selection electronics,
the so-called level-1 trigger, which will efficiently select events during high-luminosity proton-proton running. The trigger also has significant applications inheavy-ion physics and will be used, for example, forthe selection of J /'I! events in peripheral Au-Au andlight-ion collisions at increased luminosity.2) In heavyion physics, the total cross section corresponds to a
raw event rate of 14 kHz. This is well matched to the
12 kHz bandwidth of the PHENIX data acquisition.
In contrast, the maximum raw event rate from spinrunning will be 12 MHz. Therefore, no spin physics
program is possible in PHENIX without a substantial upgrade of the level-1 trigger. The upgraded trigger should efficiently select (> 80%) the interesting
physics events and substantially reduce background
events . The trigger requirements are further complicated by the necessity to be sensitive in parallel forseveral physics channels, which have small cross sections (e.g., heavy quark production, W production andDrell-Yan) , and the need to be taken in parallel withhigh event selection efficiency in each single channel.
In order to match the different physics channels withthe available data acquisition bandwidth, a reduction
factor of 5000- 10000 is needed in each channel.
We have designed and studied a level-1 trigger forthe central detector arms which performs the required
*1

*2

*3
*4

*5
*6
*7
*8

240

On leave from Aristoteles University, Greece
High Energy Accelerator Research Organization (KEK)
Kyoto University
Oak Ridge National Laboratory, USA
On leave from Reed College, USA
University of Tokyo
University of California at Riverside, USA
Waseda University

Fig. 1. The PHENIX level-1 trigger for the central detector
arms uses coincidences between the EMC and the RICH
in order to identify electrons and photons.
Table 1. Possible trigger scheme in the PHENIX central
arms. For electrons, the RICH threshold has been set
to three or more photoelectrons.

Channelsingle e
e-J.L
'Y

e (W)
Bias

EMC Thr.
700 MeV
700 MeV
5 GeV
10 GeV
4 GeV

Rej. Fac.
3000>250000>40000>40000>40000Rate
4 kHz<0.05 kHz
<0.3 kHz<0.3 kHz<0.3 kHzevent selection and data reduction. The trigger isbased on the combined information from the electromagnetic calorimeter (EMC) and the ring imaging
Cherenkov counter (RICH); the trigger's principle ispresented graphically in Fig. 1. Fast programmable
logic combines and processes information from four independent EMC thresholds and the RICH. Detailed
studies have confirmed that the trigger efficiently selects electrons, photons and jets of hadrons. 2,3) Table 1
summarizes a specific trigger scheme in which the
RICH threshold is set to the equivalent of three photoelectrons and the four EMC thresholds are set at
E = 0.7,4.0 , 5.0 and 10.0 GeV. The settings are chosen to simultaneously trigger on single electrons anddi-Ieptons (both as tags for heavy quarks) as well as
highly energetic photons (direct photon production)and electrons (W production). The trigger scheme pre-sented in Table 1 reduces the event rates in the central
arm to about half the PHENIX data acquisition bandwidth without necessitating a reduction of the event
rate prior to the event selection process. Both RICH
and EMC are required in order to achieve sufficient
raw event rejection.

N. Saito et al.: Nucl. Phys. A 638, 575 (1998).
2) T. Matsumoto: Talk at 55th Ann. Meet. of PhysicalSociety of Japan, Niigata, (2000).
3) W. Xie, B. Lillie, and D. Galanakis: Talks and Posters
at Division of Nuclear Physics of APS Meet. , Williamsburg, (2000).

References
1) D. P. Morrison et al.: Nucl. Phys. A 638, 565 (1998);

241

RIKEN Accel. Prog. Rep. 34 (2001)

Event Reconstruction in the PHENIX Muon Identifier
Y. Mao, V. Cianciolo,*1 A. Glenn,*2 K. Kurita, J. Murata, J. Newby,*2 K. Pope,*2
K. Read, *2 N. Saito, H. D. Sato,*3 S. Sorensen, *2, and A. Taketani
The PHENIX muon detector comprises two arms,
each of them includes a muon tracker, consisting of
three tracking stations, and a muon identifier, consisting of five gaps instrumented with 8.4 cm-wide Iarocci
tubes in horizontal and vertical orientations and interleaved with four layers of steel. 1)
Essentially, there are two goals for event reconstruction using the PHENIX muon identifier (MuID): (1)to find roads which will be used as initial tracks forthe muon tracker (MuTR) software since there are
too many combinations if started from the MuTR due
to both high multiplicity in gold-gold collision andfiner read-out in the MuTR ((Ix100 p,m), and (2)to do particle identification for reconstructed tracks.
To achieve both purposes, a road-finding algorithmwith two steps has been developed: 2 ) the phase-one
road finder, which presents a set of initial roads to
the MuTR software focusing on better match between
MuTR tracks and MuID roads for a higher muon reconstruction efficiency, and the phase-two road finder ,which retraces the roads accepted by the MuTR software and performs a more accurate hit pattern finding
for a better hadron rejection.
The phase-one road finding starts with a road seed,
which is constructed from a hit found in a seed gap
and vertex position measured by a vertex detector,
and then finds additional hits that are consistent withthe road trajectory. A hit closest to the projectionof the road to the gap, containing that hit within the
search window, is generally accepted. The projectionof the road is steered, and the size of the search window is adjusted to allow a deviation from a straightline trajectory due to multiscattering in the steel absorbers placed between gaps. As a default, two seedgaps are applied to handle the inefficient tubes. The
main problem in phase-one road finding is the compromise between high reconstruction efficiency and theleast number of ghost roads , in particular those due torelatively large MuID granularity: a tube is approximately 8.4 cm wide and 250- 502 cm long. We first
focus on higher reconstruction efficiency and then determine the following items to reduce the number ofghost roads: (1) X-V consistency; (2) X-V position
where the road projects to the z-vertex plane; (3) fit
quality of the road to a line; and (4) sharing of hits
between two roads. In addition, the phase-two roadfinding will further reduce the number of ghost roads
by combining information from both the MuID and the
f"..J

*1

*2
*3

242

Physics Division, Oak Ridge National Laboratory, USA
Physics Department , University of Tennessee, USA
Kyoto University

MuTR. The reconstructed roads are then available foruse as input for the MuTR software.
Once the MuTR software accepts the roads and finds
associated tracks in the MuTR, the result will be sent
back to the MuID software. The phase-two road finding performs two tasks: to further reduce the numberof ghost roads and to find all possible hits produced bya single particle penetrating the M uID. The phase-tworoad finding begins by checking the track identity andkeeps the best-matched track/road (least X2 ) if there
are multiroads pointing to the same track, which happens when a particle hits the tube overlap region in
the MuID. Furthermore, the match quality is also investigated for each matched track/road for ghost-road
reduction. The passed roads are retraced and , in general, all hits within the search window are accepted incontrast to the phase-one road finding which only accepts the closest hit, since hits associated with a roadare of crucial importance for the particle identification.
Then, we create a group of variables for each road , forinstance , the total number of hits in the road and thelast gap reached by the road, according to our previous
study on hadron/muon identification.
With all possible information for a track/road, particle identification is performed. Currently, a very
simple reference table, based on the particle momentum and the last gap, is used to separate muons fromhadrons. Two different approaches are being studied:the discriminant function analysis and extended multidimensional reference will be incorporated into the
MuID software in the near future.
The software has been intensively tested with simulated single-muon and single-pion events 3) and the latest result reveals a reconstruction efficiency of approximately 99% for muons in 2.5- 5.0 GeV /e and a pion
reduction rate of about 0.3% in the same momentum
region. We expect a better pion reduction rate after
new particle identification software becomes available.
The software has also been used to process the MuID
data during the last summer run and roads were successfully reconstructed, although the MuID was only
partially instrumented.
References
1) PHENIX Collaboration: http:/ / www.phenix.bnl.gov/
phenix/WWW /figures/jpg/2_9703phnx1.jpg
2) V. Cianciolo et al.: http://rhip.phys.utk.edu/rhip/
Phenix/muideventreconstruction.html
3) Y. Mao et al.: RIKEN Accel. Prog. Rep. 33, 46 (2000).

RIKEN Accel. Prog. Rep. 34 (2001)

Gluon Polarization Measurements in the PHENIX Central Arm
A. Bazilevsky, Y. Goto, and N. Saito
Polarized proton collisions, which we will perform at
RHIC /PHENIX, 1) are sensitive to gluon polarization,b.g( x), in the leading order. By measuring longitudinal spin asymmetry, ALL = (da++ - da+_)/(da++ +da+_), where da++ (da+_) represents the cross section with parallel (antiparallel) beam helicity, b.g(x)is extracted.
The PHENIX detector system consists of two central arms and two muon arms. In this report, we discuss physics signals in the central arms. Signals in themuon arms are discussed in another report. 2 ) In thecentral arms, each of which cover 1171 < 0.35 and 7r /2
azimuthal angle, we will measure prompt photon andneutral/charged pion production using a fine-segment
electromagnetic calorimeter (EMCal), tracking chambers and particle-ID detectors. The segmentation of
the EMCal is 0.01 radian in both the azimuthal andpolar directions.
The dominant process for prompt photon productionis the gluon Compton process, gq ~ '"'(q. We investigate the gluon distribution with a clear theoretical interpretation. The measurement is experimentally challenging because there are many backgrounds, mainly
from the two-photon decay of 7r 0 . The PHENIX detector has good background reduction capability with the
EMCal. Figure 1 shows the estimated statistical errorsof our ALL measurement of the prompt photon in one
year of full luminosity, 320 pb-I, at vis = 200 GeV. 3 )The statistics make a clear distinction between threemodels of GS95 NLO polarized PDF with different integrated gluon polarization values from 1.02 to 1. 71 at
Q2 = 4 GeV 2 • The raw ratio of experimental background to the prompt photon yield is 50% to 200% in
the Pr region from 10 to 30 GeV /e at vis = 200 GeV.
Due to the fine-segment EMCal, this ratio can be red uced by mass reconstruction of two photons and an
isolation cut down to less than 20%.4)
Pion production measurements are an alternative
to a jet measurement in a small acceptance detector.
Jet (or pion) production is sensitive to b.g(x) throughgluon + quark and gluon + gluon reactions and has
high statistics. We will be able to begin measurements
in RHIC year-2, the first year of the polarized proton collision with 10% luminosity. At PHENIX, 7r 0
is clearly identified by mass reconstruction with the
EMCal. We will obtain very clear statistics to distinguish between three models of GS95 NLO polarized
PDF. Because of the different fragmentation functionsof 7r 0 , 7r+ and 7r - from each quark, we will observe different asymmetries for each. Figure 2 shows asymmetries of 7r 0 , 7r+ and 7r- with the estimated statisticalerrors of our ALL measurement of 7r 0 in one year of 10%J

0 .2
0 . 15
0 .1
0 .05
0
-0.05
-0.1

Stotistics for 320pb"'

5

0

10

15

20

25
30
Pr (GeV/c)

Prompt -y Asym metry

Fig. 1. Statistical errors of our asymmetry measurementof the prompt photon in one year of full luminosity
at VB = 200 Ge V. The asymmetry calculations using three models of GS95 NLO polarized PDF are also
shown.

<t 0.07

0 .06
0 .05
0 .04
0 .03
0 .0 20 .01

o-0 .01-0 .02- 0.0 3 0········ ····· ·· ··········1

1-- - - - - - -- - -EJ-. -- oG ----Ill- - · .~. - - -$ -- -- ~ ---I ·--:::T" I."~tI'.'=..

St otis ti cs f or 32 pb-' 4 secto rs

2

4

6

8

10

12

PT(GeV/c)
Pion Asymmet ry

Fig. 2. Asymmetries of nO, n+ and n- with the estimatederrors of our ALL measurements of nO in one year of
10% luminosity, 32pb- 1 at VB = 200 GeV.

luminosity, 32 pb- 1 at vis = 200 GeV. This measurement is similar to the DIS semi-inclusive plus-charged
and minus-charged hadron measurement performed in
the HERMES and SMC experiments,5,6) where the researchers measured flavor decomposition of the quark
polarization. We will provide more information on theflavor decomposition of the quark polarization, in addition to the gluon polarization, in this measurement.
We will perform the direct measurement of b.g(x)at PHENIX using many channels and probes. Thesechannels cover complementary kinematic ranges of thegluon.
References
1) M. Ishihara et al.: RIKEN Accel. Prog. Rep. 34, 227(2001).
2) H. D. Sato et al.: RIKEN Accel. Prog. Rep. 34, 244(2001).
3) Y. Goto et al.: RIKEN Accel. Prog. Rep. 31 , 54 (1998);
A. Bazilevsky et al.: RIKEN Accel. Prog. Rep. 33, 44(2000) and references therein.
4) A. Bazilevsky: RIKEN Rev. 28, 15 (2000).
5) B. Adeva et al.: Phys. Lett. B 420, 180 (1998).
6) K. Ackerstaff et al.: Phys. Lett. B 464, 123 (1999).

243

RIKEN Accel. Prog. Rep. 34 (2001)

Prospects for Gluon Polarization Measurement with the PHENIX
Muon Arms
H. D. Sato,*l M. L. Brooks,*2 H. En'yo,*l N. Hayashi, K. Imai,*l K. Kurita, J. M. MOSS,*2 N. Saito, Y. Goto,
A. Taketani, and Y. Mao*3
One of the major goals of the RHIC spin project isto measure the gluon polarization (~G(x)/G(x); theratio of the polarized and unpolarized gluon density)in the proton using polarized pp collisions. The experiment will begin in 2001 at VB = 200 GeV. PHENIX,l)one of the large experiments at RHIC, is going to measure double-longitudinal spin asymmetries (ALL) for
many gluon-induced processes with which the magnitude of ~G(x) can be determined. 2) In this paper,
we focus on processes which can be studied with thetwo Muon Arms in PHENIX. Their kinematical acceptance is 1.2 < 1171 < 2.4 and ~¢ = 27[.
Since the open heavy-flavor production is dominatedby the gluon-gluon fusion process, its asymmetry is
sensitive to ~G(x).
Production of single muons with a high transverse
momentum is known to be dominated by semi-Ieptonic
decays of open heavy-flavors and has a large cross section. 300 k single muons with PT > 2 GeV / c from open
charm quarks with a 6pb- 1 luminosity are expected in
the first year. This yield corresponds to the statistical error of ALL, 8A LL (stat.) = 0.007, with 50% beampolarization. This accuracy is sufficiently precise to examine the prediction of one of the theoretical models 3)(ALL rv 0.02). It is important to measure ALL for the
hadronic decay and punch-through background since(1) ALL for the signal is diluted with it and (2) it will
also give us information on ~G(x) by itself.
Requiring the coincidence of an electron measured
in the two Central Arms, which covers 1171 < 0.35 and~¢ = 7[ , we can identify open heavy-flavors much moreclearly. Figure 1 shows the expected mass spectra
for unlike-sign and like-sign eJL pairs. We used the
PYTHIA event generator with the GRV94-LO parton distribution functions. While charm events appear
only in the unlike-sign pair, bottom events also contribute to the like-sign pair since some b-quarks decay
sequentially (b ~ c ~ l) and the sign of the lepton
is flipped. Major sources of the electron backgroundare the Dalitz decay of 7[0 and the photon conversion. Most of these can be rejected using the isolation
cut with the MVD (multiplicity vertex detector) which
covers 117 1 < 2.5 around the beam pipe. The reason forthis is that within a certain cone angle around a hit by
an electron (positron), another hit by the accompanying positron (electron) will be found. 4 ) Therefore we
can obtain ALL for both open charm and open bot* 1 Kyoto University*2 Los Alamos National Laboratory, USA*3 China Institute of Atomic Energy, China244

tom events separately using unlike-sign and like-sign
events. Both statistical and systematical errors are estimated to be sufficiently small to distinguish the different models of ~G(x) with a 320pb- 1 luminosity. 2)
ALL for the charmonium production will add another constraint to ~G (x). The detection of J /'Ij; isrelatively easy and its background is expected to besmall for the asymmetry determination. We will obtain roughly 40 k J /'Ij;'s with 6pb- 1 , which corresponds
to 8ALL(stat.) = 0.02 with 50% beam polarization.
We also plan to measure the production cross section
and the polarization of J /'Ij;. Those observables playa

e,mu mass(unllke sign pair),mu mass(lIke sign pair)

>CP

CJ

...
!.
'C

a;

:;

.

10

2

3

4

5

6

7

8

2

e,mu Mass (GeV)

3

4

5

6

7

8

e,mu Mass (GeV)

Fig. 1. Expected mass spectra for unlike-sign and likesign eJ.1- paris in pp collisions at Vs = 200 Ge V with a
320pb- 1 luminosity.

0

~
C.,)

>

10 3 t--- ------fj,~_=:Jl!l1X_--------t-7'

-

M

~

10 t---------+ --/x
Fig. 2. Sensitive regions of gluon x and Q2 for the different
processes.

crucial role in determining the production mechanismof the charmonium.
Figure 2 shows sensitive regions of gluon x and Q2for bb ---+ ef-LX , cc ---+ eX and the direct-photon production process. Since muon channels probe different
kinematical regions from those measured in the Central Arms, together they give us a more global pictureof ~G(x).

References
1) http://www.phenix.bnl.gov /2) A. Bazilevsky et al.: RIKEN Accel. Prog. Rep. 33, 44(2000) .
3) T. Gehrmann and W . J. Stirling: Phys. Rev. D 53, 6100
(1996).
4) W. Xie for the PHENIX Collaboration: American Physical Society Meet., Oct . (2000).

245

RIKEN Accel. Prog. Rep. 34 (2001)

Investigating Contact Interaction by Polarized pp Collision
J. Murata
One of the most vital tasks of an experiment usinga polarized hadron collider in a new energy region is
the study of physics beyond the standard model (SM).
In the past few years, several theoretical works havebeen devoted to the studies of contact interaction (or,compositeness) and new gauge bosons W'± and Z'.
In these theoretical works,1) it has been shown that
RHIC can reach a similar sensitivity to that of the
TEVATRON, due to its polarized beam.
The purpose of the present study is to explore thediscovery potential for physics beyond the SM from theexperimental perspective. In order to study physics
sensitivity and to determine a search window, simulation studies with an event generator are indispensable. Several non-SM scenarios can be examined using
PYTHIA. A contact interaction (CI), phenomenologically introduced as a 'residual interaction' which originates from interactions between quark and lepton subconstituents, can be also examined through it. However, as with all other subprocesses, PYTHIA includes
only helicity-averaged cross sections for the CI.
The author developed a plug-in program'POLBEYOND ' for PYTHIA by which helicitydependent matrix elements and spin asymmetries
for Drell-Yan and quark-scattering process can be
examined. Figure 1 shows the expected single spin
asymmetries AL = {a( -) - a( +)} / {a( -) + a( +)}at RHIC (JS = 500 GeV) in J.L+ J.L- pair production
assuming full acceptance and detection efficiency.
The results were obtained for various A, which isa model-independent scale parameter of the CI, defined as F(Q2) = (1 + Q2/A 2 )-1, where F(Q2) isa 'form factor ' of the quark and lepton. Helicitydependent matrix elements including CI terms wereobtained by crossing the electron-quark-scattering formula from the annihilation channel to the exchange
channel. Final hadronic spin asymmetries were estimated by accumulating events with the following
weight factors: helicity asymmetries of partonic levelcross sections, and polarized and unpolarized parton
distribution functions. The event generation was controlled by the unpolarized subprocesses, which are already included in PYTHIA for fermion pair creation
via
Z production including CI effects. The present
result shows that we can expect to observe an anoma-,* /<":: r---A .1TeV

f
~

0.06

0.04

1\_2TeVr
1\.3TeVr

0.02

1\ • • TeV
A_5TeV
S.M.

-0.02-0. 04-0.06-0.08 0

20

40

60

80

100 120 140 160

180 200

Mass (GeV/c2 )Fig. 1. AL values are plotted as functions of Drell-Yan
mass with selections of A and for the case of the 8M(A -+ (0). Present results are for the reaction of
pp -+ p,+ p,- at y's = 500 GeV, with a constructive
interference between the 8M and the left-handed CI.
G8-A 2) polarized parton distribution function is used.

Parity Violation in Jet Production by Contact Interaction at RHIC
(PYTHIA+POLBEYOND Oct 00 Jiro Murata)
:j

~

0.1
0.08
0.06
0.04
0.02

r--.,f-S-=5-0-0-G-e-V,-L-=-SO-O-p-b-:-1----::r-=--r--,.-,

A=1TeV.,fs=650GeV, L=SOOOpb- 1
A=1TeV
SM

o

o

-0.02
-0.04
-0.06
-0.08
-0.1

:j
0.1
~ 0.08
SMO.060.04
0.02

70% Polarization (dP=O)
Full Detection Efficiency
10% Systematic Error
pol-PDF = GS-95 NLO-A

o

50

100

150

-0.02
-0.04
-0.06
-0.08
-0.1

70% Polarization (dP=O)
Full Detection Efficiency
10% Systematic Error
pol-PDF =GS-95 NLO-A

0

50

100

150

P T (GeV/c)

Fig. 2. Parity-violating double-spin asymmetries Afr are plotted as functions of jet P t , for y's = 500 GeV
with 800 pb- 1 and y's = 650 GeV with 8000 pb- 1 .

246

lous parity violation if A rv 1 TeV; however , at least
the realistic detector acceptance should be considered
in order to predict a more accurate search limit. Furthermore, a full detector simulation is also possibleusing PYTHIA+POLBEYOND. Although the experimental signature of the Drell-Yan process is clean, its
small cross section in pp collisions, which requires sea
quarks, limits our sensitivity compared to the alreadyestablished limits in e+ e- collisions for the electronquark Cl (A > 5.4 TeV) by ALEPH and in frp collisions
for the muon-quark Cl (A > 2.9 TeV) by CDF. On theother hand, jet production has a larger cross section
and potentially provides better sensitivity. The estimated parity-violating asymmetries in jet production
are shown in Fig. 2. It is shown that we can reach morethan 3 TeV sensitivity, which is higher than the current

limit of 2.7TeV reported by DO for the quark-quark
Cl,3) with the current RHlC plan. It is also shownthat the sensitivity limit can be more than 6 TeV using the RHlC upgrade plan. To summarize, we notethat the observation of an anomalous parity vi<;>lation
would directly indicate the presence of new physics.
References
1) P. Taxil: Nuovo Cim. 16 No. 11, 1 (1993); P. Taxil andJ.-M. Virey: Phys. Rev. D 55, 4408 (1997); Phys. Lett.
B 404, 302 (1997); Phys. Lett. B 441 , 376 (1998); J.-M.
Virey: Eur. Phys. J. C 8 , 283 (1999).
2) T. Gehrmann and W. J. Stirling: Phys. Rev. D 53, 6100
(1996).
3) Particle Data Group: Eur. Phys. J. C 15, 852 (2000) .

247

RIKEN Accel. Prog. Rep. 34 (2001)

Polarized Parton Distribution Functions for Future Predictions
Y. Goto, N. Hayashi, M. Hirai,*1 H. Kobayashi, S. Kumano,*1 M. Miyama,*2 T. Morii,*3
N. Saito, T.-A. Shibata,*4 and T. Yamanishi*5
Based on measurements of polarized deep inelastic scattering (DIS), we determined polarized parton
distribution functions (pol-PD Fs). 1) The experimental
data of spin asymmetry A 1 at various x and Q2 are
combined in the functional fitting process using a Q2
evolution for polarized parton distributions.
The functional form of the pol-PDF fJ.!i(X, Q2) at
Q2 = Q6 (= 1.0 Gey2) is defined using four parameters
by taking into account the counting rule,

0.4..--------------------..
-

0.3

The subscript i denotes the four types of parton distributions: !i E {u v , dv , q, g}, where U v and d v are
valence quarks, 9 is the gluon, and q is a sea quark
representing all sea quarks:
fJ.u s = fJ.u = fJ.d s = fJ.d = fJ.s = fJ.s

=fJ.q.

(3)

The SU(3) symmetric sea at Q2 = Q6 is assumed,which is reasonable and within the current experimental accuracy of sea-quark measurement. The first moments of fJ. U v and fJ.d v are fixed by the ,B-decays ofneutrons and hyperons in accordance with the SU(3)symmetric sea assumption, thus the total number offree parameters is further reduced from 16 to 14.
The X2 minimization is performed using the CERN
library MINUIT. The parameters are determined byfitting the function to 375 data points of Al from DIS
experiments that are EMC, SMC, SLAC (EI30, E142,
E143, E154, E155) and HERMES. We obtained themin. value of X2 = 322.6 for the LO and X2 = 300.4
for the NLO, suggesting that the NLO is more suitable.
Figure 1 shows the determined polarized parton distribution functions for the NLO. We reported threesets of parameterization, namely, LO, NLO-1 and
NLO-2, in our previous publication,l) where the NLO1 function is fitted with 14 free parameters while the
NLO-2 function is fitted with 13 free parameters wherea q is fixed at a q = 1.0.
A FORTRAN program library used to reproduce thethree sets of pol-PDF is available from the AAC home
page. 2) The library uses grid data from pol-PDFs in
*1
*2

*3
*4

*5

248

Saga University
Tokyo Metropolitan University
Kobe University
Tokyo Institute of Technology
Fukui University of Technology

NLO....._.. x6ij(x) x 6

0.2_. - x6g(X)

E

~0.1

.'

11

o -----___ . ___ ____ ______ ~ _~ ._- . -where h(x, Qg) is the unpolarized PDF taken from the
GRY98 parameterization. The absolute value of polPDFs is constrained by the positivity condition,(2)

XdUv(X)--- xM ..(x)xFig. 1. Polarized parton distribution functions (pol-PDF)
in the next-leading-order (NLO-1) at Q2 = 1.0 GeV 2 •(x, Q2) space which covers the kinematical ranges of
10- 9 ::; x ::; 1.0 and 1.0 ::; Q2 ::; 105 Gey2. The
grid data was produced by the same Q2 evolution program used in the functional fitting. The pol-PDFs
and the structure functions gl for proton, neutron anddeuteron at a specified point of (x, Q2) are reproduced
by interpolating the grid data using the linear (forlog Q2) and cubic spline (for x) interpolation routines.
We confirmed that the library reproduces the x and Q2
dependences of pol-PDFs in our previous publication 1)
as well as the first moments. The library will be usefulfor future predictions of experimental results.
The study to determine the I-sigma boundary of
uncertainties of pol-PDFs is under way. The I-sigma
boundary can be estimated using the error matrix Vij
obtained from the functional fitting. The error of thefunction F can be calculated using the error propagation formula,(4)from the error matrix Vij of parameters ai and aj.
The level of uncertainty of fJ.g (x) that can be reduced
by including results from upcoming measurements at
DESY-HERMES, CERN-COMPASS and BNL-RHIC
is an interesting subject to which we can apply our
pol-PDF analysis.
References
1) Y. Goto et al.: Phys. Rev. D 62 , 34017 (2000); hep-ph/0001046.

2) http://spin.riken.bnl.gov/aac/RIKEN Accel. Prog. Rep. 34 (2001)

Future Transversity Measurements at RHIC
D. Boer, M. Grosse Perdekamp, and A. Ogawa*High-energy, deeply inelastic lepton-nucleon andhadron-hadron scattering cross sections can be described with the help of three independent nucleon
helicity amplitudes. Measurements of the nucleon
structure functions PI (x , Q2), the helicity average, andgl (x, Q2), the helicity difference, have explored the helicity conserving part of the cross sections with great
experimental accuracy.
In contrast, no information is presently available on
the helicity flip amplitude. The absence of experimental measurements is a consequence of the chiral-odd
nature of the helicity flip amplitude and the related"transversity quark distributions," 6q(x, Q2) , which
prevents the appearance of helicity flip contributionsat leading twist in inclusive deep inelastic scatteringexperiments.
r
The current interest in transversity distributions results from recent HERMES I ) and SMC results 2 ) insemi-inclusive deep inelastic scattering, which suggestthat Collins's function Hi- and the transversity distribution function 6q are different from 0 and measurable. Although precise statements on the shape andmagnitude of the functions cannot be made from thisdata, clearly the prospects of having a tool at handwhich, for the first time, provides access to the complete spin structure of nucleons in hard scattering processes are exciting. At DESY a significant fraction(2 years) of the extended HERMES experimental program has been designated for the measurement of thetransversity distributions. 3 )In a partonic picture of the nucleon, transversity distributions are interpreted as distributions that describe
the probability of probing a quark with spin parallel
minus the probability of probing a quark with spin
antiparallel in a transversely polarized nucleon target.
Some interesting characteristics of transversity distributions are as follows.
• Helicity flip gluon distributions are zero at leading
twist and thus there is no mixing between quarkand gluon degrees of freedom in the Q2 evolution.
• The relation between chiral symmetry breaking
and transversity in the nucleon. 4 )At RHIC , the proposal of Collins et al. 5 ) and Jaffe etal. 6 ) to utilize two meson interference fragmentation
appears to be promising7) for transversity measurements' studies of the projected asymmetry measure,8)
ments at RHIC have shown favorable results. The
relevant process is pion pair production in pp scatteringwith one proton transversely polarized. For example,
Pennsylvania State University, USA

Invariant Moss Resolution.~ 800Asymmetry vs Stat. Errors
i:-t;;5 700
RMS=12MeV

600
500

0.1 f-

EE~0.08

0.06 l-4000.04 f-300
200

0.02 f- •Statistical Errors only100

o I--,--------- ---r- .... -.... -,---

I

-0.1

10

15
p, of pcir IGeVJ

Fig. 1. Simulation studies of two-pion production in the
p-mass region for the PHENIX detector. Left plot: Invariant mass resolution for pion pairs. Right plot: Projected transverse single-spin asymmetries compared tostatistical errors, Ldt = 32 pb - 1.

Jin the p/ 0' invariant mass region, interference occurs
between two pions in a superposition of s-wave and pwave states. The spin-analyzing power of this process
is different from 0 in intervals of only a few 100 MeV
above and below the p- mass and is expected to change
sign at the p-mass. 6) Therefore, it will be important
in RHI C experiments to have sufficient invariant mass
resolution to observe the invariant mass dependence of
the analyzing power. The invariant mass resolution forpion pairs in the p-mass region is shown in Fig. 1 forthe example of the PHENIX experiment. The RMS of
the distribution is 12 MeV which is sufficient for an experimental determination of transversity distributions
at RHIC. Projected sensitivities, based on Tang's andJaffe's model calculations,6) are shown in the right plotof Fig. 1 assuming the acceptance of the PHENIX detector. The high rates will permit a transversity measurement, and a dedicated run has been added to the
future RHIC running schedule.
References
1) A. Airapetian et al.: Phys. Rev. Lett. 84, 4047 (2000).
2) A. Bravar et al.: Nucl. Phys. B 79, 520 (1999) .
3) HERMES Collaboration: The HERMES Physics Program & Plans for 2001-2006, DESY PRC (2000).
4) Talks of R. Jaffe and C. Weiss: Proc. RBRC Workshop on Future Transversity Measurements, BNL, Sept.
(2000).
5) J. C. Collins, S. F. Heppelmann, and G. A. Ladinsky:
Nucl. Phys. B 420, 565 (1994); J . C. Collins and G. A.
Ladinsky: hep-ph/9411444; J. C. Collins: Proc. RHIC
Spin Workshop, Oct. (1999), p.158.
6) R. L. Jaffe et al.: Phys. Rev. Lett. 80, 1166 (1998) ;Phys. Rev. D 57, 5920 (1998); J. Tang: hep-ph/9807560; J. Tang: Thesis, MIT (1999).
7) D. Boer: Proc. RBRC Workshop on Future Transversity
Measrements, BNL, Sept. (2000). For a discussion ofalternative channels.
8) M. Grosse Perdekamp: 8th Int. Workshop on Deep-

249

Inelastic Scattering, Liverpool, UK, 2000-8; Talks of A.
Ogawa and M. Grosse Perdekamp: Proc. RBRC Work-250

shop on Future Transversity Measurements, BNL, Sept.
(2000).

RIKEN Accel. Prog. Rep. 34 (2001)

An Electron-Nucleon/Nucleus Collider at BNL
A. Deshpande, G. Garvey,*l V. W. Hughes,*2 T. Ludlam,*3 L. McLerran,*3 P. Paul,*3 S. Peggs,*3
and R. Venugopalan
In the past one year considerable interest has developed in the experimental and theoretical nuclear
physics community to study the scope of a physics program that could be pursued if a high energy electron
beam facility is built at BNL and that beam is madeto collide with the already existing hadron beams from
RHIC. Such a facility is called eRHIC. 1 ) If the electron
beam is polarized then not only could one study unpolarized deep inelastic scattering (DIS) using the unpolarized protons (e-p) or heavy ions (e-A) at RHIC, butalso polarized DIS (e· PJ using the polarized protons
from RHIC.
The nominal electron beam energy under consideration at present is about 10 GeV, but it could be varied between 5 to 12 GeV. The variation of the proton
beam energy is already possible in the RHIC accelerators today, although this does affect the luminosity.
Using the highest possible value of the proton beamenergy possible in the present RHIC of 250 GeV anda 10 GeV electrons from a new facility one could en100 GeV. For polarized DIS
vision DIS with 0
which till now has only been pursued in fixed target
mode this would be a factor of
3 to
20 increasein the value of 0. The facility would deliver at least
1033 cm- 2sec- 1 luminosity. For unpolarized DIS off ofheavy ions, it is expected that RHIC would provide
beams of 100 GeV /nucleon. This implies that using a
10 GeV electron beam one could attain 0
60 GeVfor e-A collisions. Using the electron, proton beamenergies mentioned above and the the simple relation
between the kinematic variables it is obvious that with
eRHIC one can reach x as low as few x 10- 4 and as
high as 0.8 for Q2 ~ 1 Ge V 2. For a nuclear beam one
could reach x
10- 3 values for Q2 > 1 Ge V 2. Figure 1 shows the x - Q2 kinematic reach of the eRHIC(e-p) compared to the fixed target experiments of thepast and present.
In the case of polarized DIS off of proton beams the
program for such a collider facility is well defined: 2)
eRHIC will enable accucrate measurement of the spin
structure function of the proton and of neutron (if3He+ 2 can be stored in the RHIC ring) in the low-x
region which is the source of the largest uncertainty inthe first moments rf/ n and the Bjorken sum rule. The
spin carried by the polarized gluon inside a nucleon
is a yet unmeasured quantity. eRHIC would measurethat unambiguously and using theoretically and experimentally clean techniques of pQCD analysis at NLO,¢

Polarized ep with eRHIC 0~:::-....... SLAC + HERMES
--SMC

10

,,-,G

<Jo

olio

0'0

~0~

10 -4

x
Fig. 1. The x - Q2 kinematic coverage of the eRHIC
compared with the present and past fixed target polarized DIS experiments. A future fixed target experiment CO MPASS as CERN will cover the same kinematic range as that of SMC.

f"'V

f"'V

f"'V

f"'V

f"'V

*1

Los Alamos National Laboratory, USA*2 Yale University, USA•3

Brookhaven National Laboratory, USA

the photon-gluon-fusion process resulting in di-jet or
2 high PT oppositely charged tracks, and using photoproduction of di-jets and high PT tracks. Further
eRHIC facility would be unique in its ability to study
and resolve the polarized parton distribution inside apolarized photon. Investigations based on charged current e-p scattering would allow a first and unique measurement of the parity violating structure function g5'
There would also be other measurements possible with
eRHIC that would be semi-inclusive and exclusive innature, which will help resolve the spin structure of thenucleon along with the above mentioned measurementswith much better accuracy than possible in present day
DIS experiments and by those planned to be operational in a few years.
The investigations with e-A scattering would principally be concentrated around finding a novel state ofmatter of high parton density called in the literature
the Colored Glass Condensate (CGC).2) Indirect evidence for its existance seen from HERA data could be
confirmed with direct measurements of e-A at eRHIC.
Properties of CGC can be probed by measuring boththe inclusive as well as exclusive processes in e-A scattering. Understanding the CGC would be critical in
the investigations of QGP underway at RHIC.
References
1) For full information on the eRHIC project see
http://quark.phy.bnl.gov /-raju/eRHIC.html
2) A. Deshpande and V. Hughes: Proc. 2nd Workshop on
eRHIC at Yale, BNL Report 52592 (2000) .

251

RIKEN Accel. Prog. Rep. 34 (2001)

Computing Center in Japan for RHIC Physics (CC-J)
T. Ichihara, Y. Watanabe, N. Hayashi, S. Yokkaichi, S. Sawada,*l Y. Goto, N. Saito,
H. En'yo,*2 H. Hamagaki,*3 and M. Ishihara
The computing center in Japan (CC-J) for RHIC
physics l ) started operation in June 2000 at RIKEN.
The CC-J is aimed to be the principle site of computing for PHENIX 2) simulation, a regional PHENIX
Asian computing center, and a center for the analysis
of RHIC 3) spin physics. Since the PHENIX experiment at RHIC was scheduled to commence in 2000,
we started to construct the regional computing centerin Japan at the RIKEN Wako campus in April 1999. 4 )Prior to the construction, R&D for the CC-J started
in 1998 at the RIKEN BNL Research Center (RBRC).
The first PHENIX experiment at RHIC for Au +Au collision was carried out in the summer of 2000.
The raw data of approximately 1 TB was transferredfrom the RHIC Computing Facility (RCF) at the BNL
to the CC-J over the Wide Area Network (WAN).5)
The analyses for the first PHENIX experiment havebeen carried out successfully at the CC-J. The Ring
Imaging Cherenkov (RICH) detector demonstrated thegood identifications of the electron. 5) The calibrationof the Time-of-Flight (TOF) wall was carried out at
the CC-J and revealed clear particle identifications forhadrons. 6 ) A clear 7r 0 peak was extracted by the calibration of the Electromagnetic Calorimeter (EMCal)
and the background was evaluated by mixed event
analysis. 7 )The simulation of 100 K events for the PHENIX experiment under several conditions was carried out successfully using the PIS A code at the CC-J. 8) A fastMonte Carlo code was developed and simulation using
the code was carried out at the CC-J to evaluate theacceptance of the EMCal for 7r 0 .7)
Table 1 shows the size of the CC-J system. The CCJ is planned to reach its full scale in the three years.
At the opening of the CC-J (June 2000), the size of the
CC-J was about one-third of the goal, although almost
all the planned functions of the CC-J were completed
at that time. About 40 user accounts were created.
Figure 1 shows the configuration of the current CCJ system. The main components of the CC-J consistof (1) a High-Performance Storage System (HPSS), (2)Data servers and (3) CPU farms. Since the CC-J handles approximately 200 TB of data for year, the HPSS
was installed as a hierarchical storage system. 9 )Three SUN Enterprise 450 (E450) servers have been
installed. One E4S0 server (ccjsun) is used for login,
AFS client and general computing. AFS is a worldwide
distributed file system. External users are required tolog in to the server using Secure Shell (SSH) to access
*1

*2
*3

252

High Energy Accelerator Research Organization (KEK)
Kyoto University
Center for Nuclear Study, University of Tokyo

Table 1. The size of the CC-J system.

I 1999 I 2000 I 2001
CPU (SPECint95)
Tape Storage (TB)
Disk Storage (TB)
Tape I/O (MB/s)

CPU Farms (160 C

2400
100
2.0
45

5900
100
9
45

13000
100
15
112

RIKEN CC-J current system

32 Pentium III (700 MHz)
96 Pentium III (850 MHz)
32 Pentium III (1000 MHz)
256 MB Memory ICPU

Pentium III
Pentium III

bl
bl

RedhatLlnux

blPentium III Cd

Pentium III

LVD RAID

super
computerFig. 1. Configuration of the CC-J system.

the CC-J. Other two E4S0 servers are used for dedicated data servers. A 3.2 TB SCSI RaidS disk and a
S.7 TB Fiber Channel (FC) RaidS disk are connectedto the servers. A recent benchmark test for 2 GB fileaccess using Bonnie code revealed that the read access of the FC Raid disk (SO MB / s) is approximately
four times faster than that of LVD SCSI Raid disks(12 MB/s). The Veritas File System (VxFS), which isa type of logging file system, were adopted to obtainhigh performance in file operation and fast file system
recovery (fsck) after system failure.
These SUN E4S0 servers, HPSS servers and switching hubs for the Linux CPU farms are connected by
the Gigabit Ethernet to ensure fast file transfer andeleminate network traffic jams.

Fig. 2. Linux CPU farms.

The total required CPU performance for CC-J isabout 12 k SPECint95 (120 k SPECint2000). The mainpart of this is for simulation. We adopted the LinuxCPU farms to achieve this requirement. The current
CPU farms consists of Linux pc 's with 160 units ofIntel Pentium III processors at 700- 1000 MHz. We
adopted 10 boxes of Altacluster as a frame. Figure 2
shows a photograph of the current CPU farms. Eachnode is equipped with a dual CPU, 512 MB of ECC
memory, and a 14-18 G B local disk.
We have developed the kick-start installation
method for Redhat Linux 6.1 to the farms. The installation of Linux for each node can be carried out
with a floppy disk and a common NFS server. It takes
approximately 10 minutes to install one node and installation can be carried out simultaneously for several nodes. There is no need to use the keyboard ormouse during the installation. The post-installation
procedure is carried out automatically following the
kick-start installation.
We are currently using Linux kernel 2.2.14 and2.2.16. The NFSv3 patch for the Linux kernel significantly improved the NFS performance, particularly
for the NFS write operation. During job execution,
most of the disk lOs are carried out at the local disk
equipped for each node. At the beginning and endingof a job, file transfer will be carried out between theLinux local disk and central data server.
To keep the common software environment to be
RCF, AFS is used. To access AFS from the Linuxfarms stably, mirroring of the AFS contents to a local data server is carried out daily using the rsync
utility. AFS contents are accessed from the Linuxfarms through the NFS; thereby eliminating instabilities from the usage of AFS on the Linux platforms.
The mirrored contents of AFS at the CC-J will bemirrored again at the domestic collaborating institutes
using the rsync utility for fast update.
Since the PHENIX collaboration uses C++ for

its common software, Objectivity/DB was adopted.
Therefore, it is necessary to access the PHENIX Objectivity /DB at the RCF from the CC-J and this method
has been studied previously.l0)
The portable batch system (PBS), which is free software, was used for the batch queueing in the earlystage of the development. Job scheduler software wasdeveloped for the PBS. However , since we encounteredfreezing problems and instability in PBS, we changed
the batch queueing system from PBS to the Load Sharing Facility (LSF) in the summer of 2000. LSF is acommercial product. LSF ensures the stable operation of the batch queueing and offers the convenientfeatures of fairshare job scheduling and automatic job
recovery after node failure.
RIKEN is currently connected to Inter-Ministryresearch information network (IMnet) at the speedof 15 Mbps and this bandwidth will be updated to50 Mbps in early 2001. For the international connection, the CC-J joined the Asia-Pacific Advanced Network (APAN) which has a bandwidth of 70 Mbps overthe Pacific Ocean. Thanks to the APAN, stable access to the USA and Europe Energy Science Network(ESnet) sites has been achieved. Since the capability
for the huge data transfer (200 TB /year) between the
CC-J and the RCF is required, a data duplication facility using SD-3 tape cartridges was constructed at
the RCF and started operation in late 2000. 9 )The CC-J Planning and Coordination Office (PCO)
was established. Operation, maintenance and development of the CC-J are carried out under the charge of
the PCO. Research plans using the CC-J should besubmitted to the CC-J PCO.
The authors are grateful to Professor Bruce Gibbard
and the staff of the RCF for their earnest cooperation and discussions. They are also indebted to Professor William A. Zajc, Professor Barbara Jacak and
Dr. Dave Morrison for the coordination of the CC-J in
the PHENIX collaboration.
References
1)
2)
3)
4)

http://ccjsun.riken.go.jp/ccj/
http://www.rhic.bnl.gov /phenix/
http:/www.rhic.bnl.gov/
T. Ichihara et al.: RIKEN Accel. Prog. Rep. 33, 172(2000).
5) Y . Akiba et al.: RIKEN Accel. Prog. Rep . 34, 259(2001).
6) T. Chujo et al.: RIKEN Accel. Prog. Rep. 34, 260(2001).
7) T. Sakaguchi et al.: RIKEN Accel. Prog. Rep. 34, 261(2001), and private communications.
8) N. Hayashi et al.: RIKEN Accel. Prog. Rep. 34, 258(2001).
9) Y. Watanabe et al.: RIKEN Accel. Prog. Rep. 34, 254(2001).
10) S. Yokkaichi et al.: RIKEN Accel. Prog. Rep. 34, 256(2001).

253

RIKEN Accel. Prog. Rep. 34 (2001)

Technique for Huge Data (",200 TB /year) Storage and Transfer
between US and JapanY. Watanabe, H. En'yo,*l Y. Goto, H. Hamagaki,*2 N. Hayashi, T. Ichihara, N. Saito,
S. Sawada,*3 S. Yokkaichi, and M. Ishihara
The data volume of nuclear physics experiments has
continuously been increasing. The PHENIX 1 ) detector at the Brookhaven National Laboratory (BNL), 2)
in which the RIKEN Spin Physics project takes part,is producing 20 MB data per second. The 20 MB/s
is so large that at sucp a rate, a CD-ROM is filled
in only 30 seconds and the total nominal data volume will reach approximately 300 TB (10 9 Byte) per
year. In order to store and manage such a massive
amount of data, the primary analysis center for the relativistic heavy-ion collider (RHIC)3) named the RHIC
Computing Facility (RCF)4) introduced a huge tapelibrary system from StorageTek Inc. S ) as hardware,
which includes RedWood tape drives (11 MB/s), SD-3
cartridges (50 GB/cartridge , Fig. 1), and a huge taperobotics library PowderHorn9310 (Fig. 2) which canstore up to approximately 6,000 cartridges. This hardware is managed by the high-performance storage sys-

Fig. 1. SD-3 tape cartridge has 50-GB capacity in a small
dimension: 100 x 125 x 25 mm 3 .

tern (HPSS),6) which was developed by several US national laboratories and IBM Inc.
In RIKEN, on the other hand, we are constructing the PHENIX Computing Center in Japan (RIKEN
CC-J) 7) at Wako campus in order to maximize thephysics output of the Spin Physics project by analyzing data produced at the PHENIX detector. It is obviously important to transfer experimental data from
BNL to Wako campus. This means that the RIKEN
CC-J must also prepare a large storage system as large
as that of the RCF. Moreover, it is very importantto establish a large data transfer method between the
US and Japan. Practically, we do not have a plan totransfer an entire set of raw data but the entire datasummary tape (DST) produced after the initial analysis (reconstruction) at the RCF. However, the DST
volume is still expected to be as large as 150 TB/year.
Table 1 presents the summary of the original estimate
for the storage scale.
Figure 3 shows a schematic diagram of the storage
system of the CC-J. It is called "HPSS" because all the
hardware is controlled by HPSS which is the most upto-date hierarchical storage management (HSM) software. There is a PowderHorn9310 which is the samemodel as that of the ReF and has 5,000 SD-3 cartridges and 10 RedWood tape drives. It is shared by
the Computer and Information Division as a supercomputer's archive, and the CC-J keeps 2,000 cartridges(100 TB) and four drives for its own usage. Five IBM
RS/6000SP workstations are working to aid the traffic control of data flow among tapes and cache disks
attached on workstations and outside the HPSS (e.g .,computers for analysis). They are connected to eachother with four types of networks , as shown in Table 2.
Each type of network connection has a different function in order to avoid a traffic jam of the data flow .
The total volume and number of cache disks are also
obviously important for HSM. Our HPSS has a totalof 690 GB by five RAID5 disks for cache.
Owing to the HPSS, the storage system is taken for
Table 1. Summary of estimated volume size of data.

Fig. 2. PowderHorn931O is one of the largest tape libraries.
It can store up to approximately 6,000 cartridges.
*1
*2

*3

254

Kyoto University
Center for Nuclear Study, University of Tokyo
High Energy Accelerator Research Organization (KEK)

Raw Data
Calibration Data
Simulated Data
Data Summary Tape
Micro-Data Summary Tape
Total

PHENIX
290
0.1
30
150
45
rv515 TB

CC-J

a
0.1
30
150
45
rv225TB

100 TB The HPSS at RIKENToAnalysis

Fig. 3. Schematic diagram of the HPSS at RIKEN.
Table 2. Each RS/6000 is connected to the others withfour types of network connections to avoid a traffic jamof the data flow.
Gigabit Ethernet

Bandwidth1000 Mbps

SP Switch

1200 Mbps

100Base Ethernet

100 Mbps

lOBase Et4ernet

10 Mbps

PurposeData pathto outside
Data path
between RS /6000s
Control pathfor HPSS
Control pathfor Powder Hornan extra large (or almost infinite) disk by users which
can be accessed with only the ftp interface. As a matter of fact, users must use pftp (parallel ftp) which is
specially made for the HPSS and has the advantage ofhigher transfer speed than that of a single cache disk
or a single tape drive. Scalability is one of the big
advantages of HPSS, which means that the total processing capacity scales almost linearly to the amount of
hardware (e.g., workstations, tape drives, cache disks,
and tapes). This scalability was not realized until
the system built on the distributed computing environment was fabricated. The present HPSS has beenmeasured to have a continual write performance of
50 MB/s (peak), 12 MB/s (sustainable, when employing only two tape drives). Recently, we developed cftp
(CC-J ftp) by hacking pftp for users ' convenience andeasy management. Users can easily archive/retrieve
their own data from HPSS using cftp.
The data transfer method between US and Japanis another issue. As mentioned, 150 TB is estimatedas a nominal volume of data transferred from US to
Japan yearly. It requires 5 MB/s noninterrupted transfer for the entire year over the Pacific Ocean. In fact,
5 MB / s over the Pacific is now achievable. The AsiaPacific Advanced Network (APAN) which we are using has 70-Mbps (8.8 MB/s) bandwidth between the
US and Japan. On the other hand, the measured
transfer speed does not exceed 1 MB/s. The 15-Mbps(1.9 MB/s) bandwidth between APAN and RIKEN
may be one reason, but 0.2 s of signal delay (round-triptime) between BNL and RIKEN may be more serious.
It seems impossible to transfer all the data over the
network at present, but it may be possible in the near
future. Recently, we were pleased to find out that the
bandwidth between APAN and RIKEN will be tripled
in the near future. In addition, even 1 MB/s meansthat approximately 80 GB data can be transferred in
one day. A rate of 80 GB/day seems to be an adequatetransfer speed except for raw data or DST.
Thus, we decided to transport tapes which contain DST by air. Five MB/s means 3 TB/week whichis equal to 60 SD-3 cartridges (Fig. 1) whose dimensions are 100 x 125 x 25 mm 3 . We can archive
5 MB / s easily by placing these 60 cartridges in a boxof 400 x 125 x 375 mm3 and transporting it to the US
weekly. We are building up the duplication facility
at the RCF to copy data to our cartridges smoothly.
It consists of a RedWood tape drive and an RS/6000
workstation with a 200-GB hard disk as a data buffer.
The RedWood tape drive and 200 SD-3 cartridges are
already installed in the RCF's PowderHorn9310. The
procedure is as follows: (1) Each data set for export
is stored once in a local buffer disk of the RS/6000.
(2) When the total volume of data sets nears 50 GB,
the other local disk is set to the next buffer and makes
a tape archive of the previous disk by using a standard "tar" utility. (3) Then process (2) is repeated.
All hardware is already functioning and the first DSTexporting task is under way.
References
1)
2)
3)
4)
5)
6)
7)

http://www.rhic.bnl.gov /phenix/
http://www.bnl.gov/
http://www.rhic.bnl.gov /http://www.rhic.bnl.gov /RCF /http://www.storagetek.com/
http://www.sdsc.edu/hpss/
T. Ichihara et al.: RIKEN Accel. Prog. Rep. 34, 252(2001); http://ccjsun.riken.go.jp/ccj/

255

RIKEN Accel. Prog. Rep. 34 (2001)

Objectivity /DB System at CCJ for the PHENIX Experiment
S. Yokkaichi, H. En'yo,*l Y. Goto, H. Hamagaki,*2 N. Hayashi ,T. Ichihara, M. Ishihara, S. Sawada, *3 and Y. Watanabe
Recently, Object-Oriented (00) techniques for software development have attracted wide interest in thefield of experimental particle/nuclear physics. Manyexperiments in LHC, SLAC , FNAL and RHIC are developing their software using the OO-techniques. The
C++ programming language is the most popular 00programming language and many experiments adopt
this language at present.
In C++, it is not very easy to communicate outside of the process in the Object-Oriented manner.
Communication between Objects on memory is realized using a pointer or a reference, while it is nonsense
to write a pointer to a file. A user of C++ has todevelop his or her own methods to input/output the
ObjeCts to/from the files on a disk or to/from interprocess communication methods as a socket, because
C++ does not support such methods. In other words,
C++ supports only the Objects on memory, but does
not support the Objects on disk or Objects on network. The Object-Oriented Database (OODB) helps
to input/output the Objects to/from the disks transparently. The Objects persistently exist on the OODB
instead of existing transiently on the memory of eachprocess. (For the network case , the Object Request
Broker (ORB) helps.)
The Objectivity /DBl) system is one of the commercial Object-Oriented Database Management Systems.
It has been studied through the CERN RD45 project 2)
and the ATLAS experiment, and has already been usedin the BaBar experiment.
The PHENIX experiment also adopted C++ to develop their online/offline software, and decided to use
the Objectivity jDB for their main database. The main
DB includes detector calibration data, high voltage
values for the detectors , the run information and so on,
although there is no plan to include raw data or Data
Summary Tapes (DST). The high-voltage data part ofthis main DB system was already used throughout thelast run in 2000. The calibration-data part is partly
under development and is used in the reconstruction
process, which makes the DST from the raw data.
Collaboration-wide license of Objectivity/DB permits
the use of the system in any institute in the PHENIX
collaboration.
Also in CCJ,3) we are supporting the access of the
PHENIX official database (PHENIX-DB) for regional
users who would like to analyze the raw data. Various ways to support the database are discussed. (A)
*1
*2
*3

256

Kyoto University
Center for Nuclear Study, University of Tokyo
High Energy Accelerator Research Organization (KEK)

To make a 'snap-shot' of the original PHENIX-DB on
BNL using the tool built in the Objectivity/DB system. It supplies a dead copy of the PHENIX-DB on
the disk at CCJ and the user can read it and obtain thesame data as in BNL. (B) Direct access to the original PHENIX-DB on BNL from CCJ via a Wide Area
Network (WAN). Objectivity/DB supports two accessmethods via the network. One is via the Network File
System (NFS), and the other is via the Advanced Multi
Thread Server (AMS), which is the original techniqueof Objectivity/DB. In a WAN environment, AMS isa unique solution in fact. We have accessed via AMS
and measured the overhead time caused by WAN between CCJ and BNL. It is in the order of 20 to 30
minutes for a typical PHENIX official reconstruction
routine which requires only 20 to 30 seconds to reada local database. This overhead time is significant.
Moreover, possible locking of the PHENIX-DB causedby this long-time and unstable access may bother theusers in BNL. Users who were accessing the DB werealready bothered in the last run by the locking of the
PHENIX-DB caused by dead processes or living andforgotten processes in BNL.
Now method (A) is adopted in CCJ. Each time amajor update is made at BNL, a 'snap-shot' of the
PHENIX-DB is created and copied to CCJ by handusing the built-in commands 00 backup, oorestore andooinstallfd. Many users of CCJ have already used thecopied DB and analyzed raw data for their own interests as detector calibration.
The current size of the PHENIX-DB is approximately 600 MB, and the copying process takes about
10 minutes. It is not heavy at present, but it is projected that the DB size will reach an order of 10 GB.
In such a case, it is difficult to copy the entire DB; thusincremental copying is preferable. There are two methods to realize the incremental copying. One is (C) ,called Replication, supported by the Objectivity/DB
system, which makes a copy (or copies) of the DB inreal time. Connections between DBs are kept permanently and an update of one DB propagates to otherDBs automatically. However, the problem of locking
in the unstable WAN environment also exists. Another method, (D) , uses a special tool developed in
the BaBar experiment at SLAC. The people in BaBar
use Objectivity/DB for the data storage and copy thedata from Objectivity/DB to outside of SLAC incrementally using their special too1. 4 ) We plan to ~ontact
them and study their tool to determine whether it issuitable for our usage or not.

References
1) http://www.objectivity.com/
2) http://wwwinfo.cern.ch/asd/rd45/index.html

3) T. Ichihara et al.: RIKEN Accel. Prog. Rep. 34, 252(2001).
4) E. Leonardi and S. J. Patton: Proc. CHEP 2000.

257

RIKEN Accel. Prog. Rep. 34 (2001)

Large-Scale Simulation of Au-Au Collision for PHENIX Year-l
N. Hayashi , T. Ichihara, Y. Watanabe, S. Sawada,*l S. Yokkaichi , Y. Goto, H. En'yo,*2, H. Hamagaki,*3
M. Ishihara, and C. F. Maguire*4
The PHENIX 1) experiment at the Relativistic
Heavy Ion Collider (RHIC) successfully started in summer 2000. The first year, PHENIX collected of Au-Au
collision data mainly at ) S N N = 130 GeV (the centerof mass energy per nucleon), and its detector configuration evolved during that period. A large numberof Monte Carlo simulation (MC) data are necessary tounderstand the detector characteristics, such as acceptance or efficiency, and to evaluate our reconstruction
program. Thus , we started the generation of five different sets of 100 K MC events in various configurations.
The five sets are:
• Retracted configuration of the Central Arm withno magnetic field. PHENIX has two Central
Arms, East and West. Initially, they were both
open against a beam pipe about 40 em long. In
other configurations, the Central Arms are always
in a standard position.
• Zero magnetic field strength.
• Full magnetic field strength with 2D (two dimensional) field map.
• Full magnetic field strength with 3D (three dimensional) field map.
• Half magnetic field strength with 3D field map.
RIKEN CC-J (PHENIX Computing Center inJapan)2) has been established recently and one of its
major roles is to produce a large amount of PHENIX
simulated data.
The procedure for the project is described as follows.
(1) Minimum bias Au-Au collision event is generated
by HIJING event generator 3) and recorded into a
file.
(2) It is fed to the GEANT 4L based PHENIX detector
simulator, PISA. 5) This is the most CPU-intensive
step.
(3) The output needs to be processed through "response chain" to make a "fake" PHENIX Raw
Data File (PRDF) from the GEANT hit file. It
is also called a "digitization path" and produces
relational data to evaluate reconstruction programat a later time. The relational data describe therelation between the GEANT hit file and PRDF.
*1

*2

*3
*4

258

High Energy Accelerator Research Organization (KEK)
Kyoto University
Center for Nuclear Study, University of Tokyo
Vanderbilt University, USA

Table 1. Typical CPU time and Data size for a job. Presented CPU time is for the Pentium III (850 MHz) processor. Response chain's products are PRDF and relational data for later evaluation.
HIJING
PIS A
response
reconstruction
Total

CPU (hrs)
0.2
47
3.5
1.7
52.4

Data (MB)50
850
160 + 270401370(4) The event reconstruction program analyzes thisfake PRDF. In principle , it should be exactly thesame as one used for real data. Both "response"and "reconstruction" program are coded by C++
language based on the Root framework,6) an Object Oriented data analysis framework.
(5) All generated data are archived into the HPSS 7 )(High Performance Storage System) and transferred to BNL to make them available to all
PHENIX collaborators.
Typical parameters of one job (1000 events) is shownin Table 1. Each MC data set described above has 100
jobs and in total the factor 5 has to be multiplied to
the values listed in this table. This represents 26,000
hours of CPU time and 635 GB of data volume.
In order to archive files into HPSS , PftP (parallel ftp)
is used. Its speed is about 10 MB/sec.
Because the security at BNL is enhanced using afirewall technique, ftp does not work in practical application. We use scp (secure copy command) insteadof ftp to transfer data to BNL. The data transfer speed
realiy depends on the WAN condition, although 100150 kB/sec for one scp session can be achieved. We
also use TAPE media to transport some of the datafrom CC-J to BNL.
References
1) M . Ishihara and G. Bunce: RIKEN Accel. Prog. Rep.
34, 227 (2001) .
2) T. Ichihara et al.: RIKEN Accel. Prog. Rep . 34, 252(2001).
3) http://www-nsdth.lbl.gov;-xnwang/hijing/index.html
4) http://wwwinfo.cern.ch/asd/geant/index.html
5) http://www.phenix.bnl.gov /phenix/WWW / simulation/Simulation.html
6) http://root.cern.ch/7) Y. Watanabe et al.: RIKEN Accel. Prog. Rep. 34, 254(2001).

RIKEN Accel. Prog. Rep . 34 (2001)

Analysis of the PHENIX RICH Detector Using CC-J
Y. Akiba,*1 T. Sakaguchi,*2 S. Sawada,*1 K. Shigaki,*1 and S. Yokkaichi
Among four experiments at the Relativistic Heavy
Ion Collider (RHIC) , the PHENIX experiment has thebest capability for lepton measurements including electrons. The Ring Imaging CHerenkov (RICH) detector is the primary device for electron identification in
the PHENIX central arms. 1) It is a threshold-type gas
Cherenkov detector with 5120 photomultiplier tubes(PMTs) as photon detectors. Its Cherenkov thresholdfor pions is 4.9 GeV Ie with its CO 2 radiator.
In June 2000 , RHIC achieved the first collision, andthe first year data were taken during the summer with
Au + Au ions at JSNN = 130 GeV. PHENIX has
accumulated more than five million events.
In order to establish an effective way of identifying
electrons with RICH, fundamental analysis is necessary, including the determination of tos (start timingof TACs), TAC conversion coefficients, and gain coefficients for the ADC channels, slewing correction , efficiency correction for each ADC, and geometry correction for the mirrors. Analysis of the RICH performance is also necessary, such as determining thenumber of fired PMTs for electron candidates, and thenumber of photo-electrons per Cherenkov ring. Because all of these should be performed with real dataand electron production is a relatively rare process, alarge amount of PHENIX real data (PRDFs) must be
stored and processed. We have copied a large fractionof PRDFs from the RHIC Computing Facility (RCF)
to CC-J 2) through WAN, and they have been stored
on RAID disks and HPSS. Because of the rich storage area and the number of high performance CPU s at
CC-J, the analysis of PRDFs and resulting DSTs has
been smoothly iterated. DSTs for about 500 k eventswere produced, which were used also for the analysis of
the PHENIX time-of-flight detector. 3 ) As an exampleof the results, Fig. 1 shows the ring-shaped distribution of Cherenkov photons. The radius of the ring isabout 6 cm, which is consistent with the design value
for the CO 2 radiator. After determining the threshold for the number of photo-electrons per ring, electron candidates can be assigned. Figure 2 shows the
Elp ratio for all the tracks and for the electron candidates. Please note that the energy (E) is measured
using an electromagnetic calorimeter and the momentum (p) is determined from the track reconstruction.
It is evident that our RICH has an excellent capability
in distinguishing electrons. We are going to continue
to clarify the RICH performance in more detail, and toobtain physics results, such as vector mesons in hightemperature, in the near future.

Fig. 1. Accumulated ring image.

Fig. 2. E/p ratio for all the tracks and the electron candidates determined from RICH.

We would like to thank the members of the Radiation Laboratory for their support of our project,
especially Dr. T. Ichihara, Dr. Y. Watanabe, Dr. N.
Hayashi, and other CC-J staff. We are indebted to Dr.
Y. Goto for the data transfer from RCF to CC-J.
References
1) Y. Akiba et al.: Nucl. Instrum. Methods Phys. Res. A
433, 143 (1999).
2) T. Ichihara et al.: RIKEN Accel. Prog. Rep. 34, 252(2001) .
3) T. Chujo et al.: RIKEN Accel. Prog. Rep. 34, 260(2001).

*1 High Energy Accelerator Research Organization (KEK)*2

Center for Nuclear Study, University of Tokyo

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RIKEN Accel. Prog. Rep. 34 (2001)

Hadron Measurement at RHIC /PHENIX
T. Chujo,*1 A. Kiyomichi,*2 H. Ohnishi,*1 and M. Suzuki*2
Heavy ion collisions at ultra-relativistic high energy
offer the possibility of producing highly condensed nuclear matter, which may undergo a phase transition
from normal nuclear matter to a de-confined state,
the Quark Gluon Plasma (QGP). In the summer ofyear 2000, Relativistic Heavy Ion Collider (RHIC) at
Brookhaven National Laboratory (BNL) began its operation as the first Heavy ion collider and energy density producing via heavy ion collisions at RHIC will
be able to generate highest energy density ever have,indeed RHI C opens a door to new era to searching andstudying for QGP.
The phase transition to QGP should also make asignificant difference in the Equation of State (EOF)
of nuclear matter and may reveal itself in the dynamical evolution of the interaction region, i. e. dynamics
of hadrons might change its state before and after thephase transition. Identified hadron measurement arrows not only investigate QGP formation but also to
explore dynamical feature of heavy ion interaction. For
example, the systematic study of particle yields relates
to baryon stopping via proton/anti-proton ratios, tothe existence and mechanism of enhanced productionof light strange mesons via K/7r and K/p ratios, and tocomparisons with predictions of chemical and thermal
equilibration in these collisions.
The PHENIX experiment collected more than fivemillion of Au+Au collisions at VB = 130 GeV per nucleon during year 2000. Generated particle are detected by PHENIX-Central Arm spectrometer. Particle identification is performed by Time-of-Flight (ToF)
measurement. The PHENIX Beam/Beam Counter(BBC) provides start timing of ToF measurement. The
BBC consists of two arrays on either side of the interaction region; each consisting of 64 photomultipliertubes equipped with quartz Cherenkov radiators. Timing resolution ofBBC achieved 20ps at central Au+Au
collisions. The PHENIX ToF wall provides stop timing of ToF measurement, located about 5.0 m from thevertex. ToF consists of 960 elements of plastic scintillation counters with photomultiplier tube readouts. One
million of Au+Au collisions events out of five millions

*1
*2

260

Brookhaven National Laboratory, USA
University of Tsukuba~20 ~----------~--~~-----------oS

-'+
.c

.2'

'0

15

cb

E

i=1

-3

-2

-1

o

123

Momentum [GeV/c]

Fig. 1. Identified 7r± , K±, proton and anti-proton bands as
measured with ToF and tracking detectors.

events are analyzed at CC-J. 1,2) Detector calibrationof ToF wall is done at CC-J and finally, ToF resol ution is achieved 120 ps for overall ToF measurement.
Figure 1 shows the quality of particle identification for
hadrons measured with ToF and tracking detectors.
Clear separation for particles is seen in this figure.
In summary, PHENIX collected more than five million of Au+Au collisions at VB = 130 GeV per nucleon
during year 2000. The PHENIX ToF measurements
and tracking system are working as we expected andthe efforts to withdraw physics from the data are underway.
We would like to thank support from the membersof the Radiation Laboratory for our project, especially
Dr. T. Ichihara, Dr. Y. Watanabe, Dr. N. Hayashi , andother CC-J staffs.
References
1) T. Ichihara et al.: RIKEN Accel. Prog. Rep. 34, 252(2001).
2) Y. Akiba et al.: RIKEN Accel. Prog. Rep. 34, 259(2001).

RIKEN Accel. Prog. Rep. 34 (2001)

7r

0

Acceptance and Efficiency for PHENIXElectromagnetic Calorimeter

T. Sakaguchi,*l S. Botelho,*2 G. David,*3 H. Hamagaki,*l S. Kametani,*4 T. Matsumoto,*lS. Mioduszewski,*3 K. Oyama,*l T. Thomas,*3 H. Torii,*5 and C. Woody*3 for the PHENIX Collaboration
Directly radiated thermal photons are an interesting probe for investigating the characteristics of thequark gluon plasma (QGP) because they have a longmean free path compared to the size of the nuclear volume involved in relativistic heavy ion collisions. The
electromagnetic calorimeter (EM Cal) of the PHENIX
experiment 1) is a device used for identifying photons,
measuring their position and energy, and providing themeans to trigger rare events, where photons are produced with a high transverse momentum. 2)
To derive the component of thermal photons from alarge background due to , 's from 7r 0 and 7] decay, it isnecessary to obtain the precise numbers of 7r 0 and 7] ,the decay photons of which have to be subtracted fromthe measured inclusive gammas. Also, the 7r 0 spectra themselves may give information on nuclear effects
such as jet quenching. The production cross section of
7r 0 or 7] can be derived from the raw counts together
with the knowledge of the acceptance and efficiency ofthe detector.
We have developed a Fast Monte Carlo code whichenables faster calculation than by using PIS A 3) basedon the GEANT simulation code. The software generates 7r° ' S and 7]'S with rapidities and transverse momentums (PT'S) following the given rapidity and PT
distributions, respectively. The particles are generated
isotropically in azimuth. The software then generates
the secondary , 's decaying from primary particles witha specific branching ratio. The quantities recorded are
the four momenta of the primary particles (7r° ' S and7]'s) and the secondary , 'so The number of hits inboth fiducial areas and veto areas is recorded as well.
The software also records the invariant mass spectrum
calculated from the decayed gamma of 7r°'S and 7] 's.
The geometry of the calorimeter as instrumented for
RHIC Year-1 operation has been implemented using
the code with a simple plug-in.
In the simulated and real data analyses, the asymmetry (a) cut and PT cut are applied to derive a clear
7r 0 peak in invariant mass spectra. The asymmetry isdefined as a = lEa - Ebl/(Ea + Eb), where Ea and Eb
are the energies of ,'so To deduce the production crosssection of 7r°'S from the number of reconstructed 7r° ' S,
the acceptance and efficiency should be calculated asa function of a cut and PT cut.
Figure 1 shows the result of the acceptance calculation as a function of PT and a cut for 7r 0 . The PT
ranges from 0 to 10 GeV with a bin width of 0.25 GeV,
which is assumed to be a flat distribution in order toincrease statistics at higher PT, and the a cut ranges
from less than 0.1 to 1 with an increase of 0.1. The
rapidity distribution is assumed to be flat from -2 to2, resulting in 1600 particles per event. The smearing
effect on energies due to the detector resolution or electric noise is not included. Thus, the calculated value isderived only from the geometric factor of the detector.
We have divided the calculation into 40 energy bins
which are mutiplied by 10 asymmetry cuts, resulting
in 400 processes. Each calculation takes about 2 hours
for 50 K events. Using CC-J , we could run 90 processes
simultaneously, and thus obtain the results for a given
geometry in about 10 hours.
The software can play a role in efficiency calculations as well. We smear the energy of the photon witha known in situ detector resolution, then accept or reject it according to the energy-dependent photon PID
efficiency. Finally, we check if the invariant mass ofthe surviving photon pairs is still within the 7r 0 mass
window used in the data analysis. For this purpose,the software is rewritten in C to enable easy additionor modification. The efficiency calculation will also be
performed in the near future.

Center for Nuclear Study, University of Tokyo
University of Sao Paulo, Brazil
BNL, USA
Advanced Research Institute for Science and Engineering,
Waseda University
Department of Physics, Kyoto University

1) PHENIX Conceptual Design Report , BNL (1993) (unpublished).
2) G. David et al.: IEEE Trans. NucL Sci. 45, 692 (1998).
3) P. Chand et aL: PHENIX Technical Notes, BNL (1999)(unpublished).

*1
*2
*3

*4
*5

1.0
~ 0.8

;::

.s 0.6

~
~ 0.4

~

0.2

Fig. 1. The acceptance of KO as a function of transverse
momentum (PT) and asymmetry (ex) cut.

References

261

RIKEN Accel. Prog. Rep. 34 (2001)

Theoretical Activity In the RIKEN-BNL Collaborationt
T. D. Lee and N. P. Samios
This is the first time the theory division of the
RIKEN-BNL Research Center (RBRC) is contributing to the RIKEN Accelerator Progress Report. The
RIKEN-BNL Research Center was inaugurated on
September 22nd, 1997. It is a joint project of the Institute of Physical and Chemical Research (RIKEN)
of Japan and the Brookhaven National Laboratory(BNL) of the United States, dedicated to the researchof the strong interaction. The Center is located in thesame building with the Physics Department of BNL,and maintains close ties with nearby institutions suchas Columbia University in the City of New York, theState University of New York at Stony Brook, theMassachusetts Institute of Technology, as well as withRIKEN and BNL.
The Center aims at promoting young physicists: fellow appointments are for up to five years and postdoc appointments are for two to three years. In addition, several tenure-track positions are created jointlywith US universities interested in strong-interaction
researches. \iVhen the Center started, its theory division hired three postdocs (H. Fujii, M. Wingate and Y.
Yasui) and two fellows (D. Kharzeev and D. Rischke).
Since then seven more postdocs (D. Boer, S. Sasaki,
J. Schaffner-Bielich, Y. Nara, Y. Aoki, K. Itakura andK. Orginos) and two more fellows (T. Blum and W .
Vogelsang) have been hired. Nine joint-tenure track
fellows (S. Bass, D. Kharzeev, A. Kusenko, A. Sch~ifer,
D. Son, M. Stephanov, B. van Kolek, R. Venugopalan,
T. Wettig) also have been appointed. Among the four
postdocs who have left (Fujii, Yasui , Sasaki, Wingate),two (Fujii and Sasaki) have gone to take permanent positions in University of Tokyo. A fellow (Kharzeev) became a joint-tenure track fellow and then was tenured
at BNL. Another fellow (Rischke) is considering anoffer of a full-professorship in Europe. In contrast, all
the senior scientists (more than a dozen) , including
the director and deputy director, are volunteers fromJapanese and American institutions.
The activities of the Center cover most sub-fieldsof strong-interaction physics: phenomenological QCD(quantum chromodynamics) , perturbative QCD andlattice QCD. Understanding proton spin is one of

We thank RIKEN and the US Department of Energy

262

the biggest challenges in strong-interaction physics today. Another important frontier lies in the understanding of QCD under extreme conditions such as hightemperature and density. In both these frontiers the
RBRC members have been quite successful, attacking
the problems by both perturbative and lattice methods. Our strength in these two rigorous methods has
also attracted many creative phenomenologists.
In the fall of 1998 the RBRC completed a 600 Gflops"QCDSP" parallel super computer in collaboration
with Columbia University and BNL. It was awarded
the Gordon-Bell Prize at the "Super Computing 98"
international symposium in the same year. Since
then, a new "RIKEN-BNL-Columbia-KEK" lattice
QCD collaboration has been very successfully using
this computer and its 400 Gflops sister computer atColumbia University. In particular the collaboration pioneered the application of the five-dimensional
domain-wall fermion method in lattice QCD. To follow
up, RIKEN , Columbia University and IBM Research
agreed to start another collaboration to develop a newparallel computer for lattice QCD capable of 10 Tflops
called QCDOC (QCD "On a Chip").
The theory division maintains close cooperation
with the BNL theory groups as well as the experimentdivision of the Center, especially in holding seminars
and workshops. Four separate series of weekly seminars are held: (1) Spin Physics, Thesday, organizedjointly with experiment division, (2) High-Energy Theory, Wednesday, organized jointly with BNL highenergy theory group , (3) Nuclear Theory, Friday, organized jointly with BNL nuclear theory group, and (4)RBRC Lunch, Thursday, organized by Rischke (97- 98)
and Blum (98- 00). The Spin Physics series gathers
both theory and experiment members. Theory seminars are mainly for exchange of ideas with outsidetheorists. Lunch seminars are mainly for internal exchange. There have been thirty workshops, all published as proceedings. In addition 150 research papers
by RBRC staff scientists have been published. In thefollowing are the summary of our research activities forthis year.

RIKEN Accel. Prog. Rep. 34 (2001)

Soft-Gluon Effects in Prompt-Photon Production
W. Vogelsang
Prompt-photon production, pp,pp,pN ---+ ,X, hasbeen a classical tool for constraining the unpolarized
gluon density: a photon can be produced in the reaction qg ---+ ,q, giving rise also to a distinct clean signal. Using polarized proton beams at RHIC is a very
promising method for measuring the nucleon's spindependent gluon density, ~g , which is currently oneof the most interesting quantities in nucleon structure.
Figure 1 shows theoretical predictions 1 ) at the 'nextto-leading-order' level of QCD for the spin asymmetry
to be expected at RHIC, for various conceivable llg.
A pattern of disagreement between theoreticalpredictions and experimental data for unpolarized
prompt-photon production has been observed in recent years. The most serious problems are related to
the fixed-target region, where NLO theory dramatically underpredicts some data sets. At collider energies, there is less reason for concern, but also here theagreement is not fully satisfactory. In view of this, various improvements of the theoretical framework havebeen developed.
'Threshold' resummations have been applied 2 ) to theinclusive prompt-photon cross section. When the initial partons have just enough energy to produce thehigh-Pr photon and the recoiling jet , the phase space
available for gluon bremsstrahlung vanishes, resulting
in large logarithmic corrections to the partonic crosssection due to imperfect soft cancelations between realemission and virtual corrections. Threshold resummation organizes this behavior to all orders in as. For
prompt photons at fixed-target energies, one finds asignificant, albeit not sufficient, enhancement of thetheoretical prediction. 2 )If the initial partons, e.g. , in the Compton process

qg ---+ ,q have a nonzero kr, the ,q pair in the final state will acquire a net transverse momentum Qr,
which may make the process softer than it would beotherwise and result in an additional enhancement of
the photon Pr spectrum. First applications 3 ) of thisidea simply assumed a Gaussian dependence on kr andhad a marked phenomenological success. On the other
hand, they were lacking a solid theoretical framework.
This was provided in Ref. 4, where a simultaneous
resummation in both threshold and transverse momentum logarithms was achieved. Contributions to thehard scattering function associated with threshold resummation were redistributed over soft gluon transverse momenta, simultaneously conserving energy andtransverse momentum. Large logarithmic correctionsin Qr arising in the threshold region were resummed
jointly with threshold logarithms. The possibility of
performing this joint resummation is ensured by thefactorization properties of the partonic cross section
near threshold. The jointly resummed cross section isshown in Fig. 2. A substantial enhancement is found.
10 4
pN.

1111<0.75
102

:z
0

"A

~

100

"0.

'"

"b

;,
rz:l

10- 2

10-4

4
left: E",,=200 GeV
right: E",,=500 GeV

Ro=0.4.

"'71<0.35

1012
PT (GeV)Fig. 2. The prompt-photon cross section at NLO (dotted),
with pure threshold resummation (dashed) , and withthe joint resummation of Ref. 4 (solid). The data arefrom the E706 experiment. 5 )solid: GRSV SrD
dashed: GRSV MAXg
dotted: GS-C

0.2

E b..... = 530 GeV

b

't;<I

II

:I 0.1«0.0

1··1·····
1020··l· ·········f·····........

30

Por,. (GeV)

40

50

20

30

40

50

Por,. (GeV)

Fig. 1. Double-spin asymmetry for prompt photon production in polarized pp collisions at RHIC.l)

References
1) S. Frixione and W. Vogelsang: Nucl. Phys. B 568 , 60
(2000); see also, G. Bunce, N. Saito, J. Soffer, and W.
Vogelsang: hep-ph/000721S.
2) S. Catani, M. L. Mangano, P. Nason, C. Oleari, and W.
Vogelsang: JHEP 9903, 025 (1999).
3) L. Apanasevich et al.: Phys. Rev. D 59, 074007 (1999) .
4) E. Laenen, G. Sterman, and W. Vogelsang: Phys. Rev.
Lett. 84, 4296 (2000); hep-ph/OOlOOSO.
5) E706 Collaboration, L. Apanasevich et al.: Phys. Rev.
Lett. 81 , 2642 (199S).

263

RIKEN Accel. Prog. Rep. 34 (2001)

New Understanding of A Polarization from Unpolarized Scattering
D. Boer, M. Anselmino*l , U. D'Alesio,*2 and F. Murgia*2
Large asymmetries P N have been observed in p+p ~AT+ X in which the polarization of the A is orthogonal
to the production plane. Here P N is defined as= u(pp ~ ATX) - u(pp ~ A! X)P
Nu(pp ~ AT X) +u(pp ~ A! X) .

(1)

The main features of this asymmetry are as follows.
The magnitude grows as a function of Pr and XF =2PL/ yS; above Pr ~ 1 GeV it flattens off (for verylarge Pr it is expected-to fall-off completely, but thishas not been demonstrated experimentally yet); it is
to a large extent yS independent.
Many models exist that try to describe this asymmetry, but none of them allow for a perturbative QCD
analysis. However, for large yS and Pr, factorization(see Fig. 1) should hold. The question arises which
partonic functions fit into this description, since noneof the standard parton distribution and fragmentation
functions can generate such asymmetries. Perturbative QCD corrections do not produce large transverse
spin effects, since they are proportional to aSmq/~.
The new proposal l ) is to use the so-called Polarizing
Fragmentation Functions (PFFs). 2) Such functions describe the fragmentation of an unpolarized quark intoa transversely polarized hadron (for the case at handa A) plus anything else (Fig. 2). These functions are
dependent on the transverse momentum of the A compared to the parent quark (orthogonal to the transverse
polarization of the A) ; they require final state interactions to be nonzero, but they are allowed by parity
and time reversal invariance. It is crucial to note thatthe polarization only arises in the final state; the initial state only determines the relative amounts of ud, s quarks, that fragment into the final state. Thi~
picture should apply to the current (not to the target) fragmentation region and hence, generates different signatures from for example recombination models.
If fitted in one experiment, the PFFs can be used
to predict other observables. Thus the proposed approach is model independent , since it is a factorized
description. The polarizing fragmentation effect itself
can in principle be modeled, but in any case one does
not need to model the process(es) as a whole. This isa huge gain in predictive power.
So far only cross section expressions in terms of the
PFFs had been given. 2- 4 ) Recently the first quantitative study has been performed: l ) the fit to the PN
data using the PFFs has yielded very good results:
reasonable functions were obtained, all qualitative features of the asymmetry were reproduced, including the
*1
*2

264

Department of Theoretical Physics , University of Torino,
Italy
INFNjDepartment of Physics , University of Cagliari, Italy

Fig. 1. A factorized diagram contributing to PN.

fact that the asymmetry for A is consistent with zero.
These fits will allow to make predictions for near futuredata and this is in progress.
One near future experimental prospect is thatHERMES and COMPASS could measure semiinclusive DIS 3 ) (£ p ~ f' AT X) in the current fragmentation region. The other important near future
option is the BNL-RHIC collider, which can reveal
whether P N i- 0 persists at even larger values of yS
and whether it indeed falls off at high Pr. We notethat at RHIC energies the scale in the PFFs themselves need not be high (of order pr), unlike the case
~ AT jet X, where ALEPH andof e+ e- ~ Zo PAL have measured transverse polarization to besmall (percent level). This could be seen as an indication that the PFFs decrease with energy. Finally,
it is worth mentioning that in principle one would also
be able to measure PN in pA or AA ~ AT X at RHIC.
References
1) M. Anselmino, D. Boer, U. D'Alesio, and F. Murgia:
Phys. Rev. D 63 054029 (2001); hep-phjOOl0291.
2) P. J. Mulders and R. D. Tangerman: Nucl. Phys. B 461,
197 (1996).
3) D. Boer, R. Jakob, and P~ J. Mulders: Nucl. Phys. B
564, 471 (2000).
4) D. Boer, R. Jakob, and P. J. Mulders: Nucl. Phys. B
504, 345 (1997) ; Phys. Lett. B 424, 143 (1998).

RIKEN Accel. Prog. Rep. 34 (2001)

Hard QCD and RHIC Spin Physics
Y. Yasui
The RHIC Spin Physics Project plans to conduct
experiments on high-energy polarized pp collision. A
70% polarization of beams and the highest energy of
y's = 500 GeV at the center of mass system are expected to be realized. The main aim of this Project is
to study the origins of the nucleon spin. The Projectwill provide useful information on the proton spin
structure. 1) For example, the gluon component in thepolarized proton will be investigated by analyzing thesingle-photon production process (pp - t , + X) andthe jets production processes (pp - t J et8 + X). It is
widely believed that the gluon component in the polarized proton plays an essential role in causing the spin
crisis problem of the proton spin structure function gl.
In the parton model, the cross section of the highenergy pp collision is factorized into soft QCD parts(distribution functions and fragmentation functions)and hard QCD parts (cross sections of partonic subprocesses). The nature of the asymptotic freedom makes
it possible to analyze the hard parts within the framework of the perturbation theory. As in previous examples, perturbative QCD (pQCD) calculations of thejets production processes are necessary to investigate
the spin structure of the proton.
These pQCD calculations have conventionally been
carried out using Feynman rules and Feynman diagrams. However calculations for jets production processes often require a large number of Feynman diagrams. To make matter worse, due to the complicatedstructure of the gauge boson interactions, the calculations are extremely difficult even at lowest order of thepertur bation theory (tree level).
Recently, we have seen much progress in the methodsof perturbative calculations. 2 ) Mangano and Parke 3 )developed methods for simplifying multijets amplitudes at the tree level. In their methods, they categorized the color structure and the helicity of the initial and final particles. Then, they decomposed the full
amplitudes into color-ordered subamplitudes which aredescribed by the spinor helicity basis. They also introduced a new technique using supersymmetry. There
were also several breakthroughs on the higher order
pQCD calculations. Bern and Kosower 4 ) introduced a
new technique for computing the one-loop-level pQCD
amplitude, which is called the string-inspired method
and/or the Bern-Kosower rule. The idea is based on
the superstring theory. The background field gauge isanother powerful method. In this gauge, we can construct the gauge-invariant effective action, which is invariant under the gauge transformation of the classicalbackground field.
In this Project , we are conducting a theoretical
study on RHIC Spin Physics. In particular, we arefocusing our attention on the hard QCD parts of thejets production processes at the high-energy polarized .
pp collision. Because of the relatively large value ofthe QCD coupling constant, higher order corrections
are not negligible in the pQCD analysis. However, thenon-Abelian structure of the gauge boson coupling andthe large number of Feynman diagrams make higher
order calculations increasingly difficult. In Ref. 2, wepointed out that the combination of the backgroundfield gauge, the color decomposition and the spinor
helicity basis is a very powerful method for loop calculations in pQCD. This method simplifies the Feynman
rules and reduces the number of intermediate terms
and Feynman diagrams required for the calculations.
The simplification has been demonstrated in an example of a five-gluon amplitude at the one loop-level(gg - t ggg). This is one of the most difficult parts inthe calculation of the next to leading order contribution for the three jets production processes. 5 ) As a simplest example, we show a result of the one-loop-level
color-ordered five-gluon amplitude in the maximalhelicity-violating case (the polarizations of all external
gluons are +1),2,3)(MHV)m 5 ;1=i(y'2)5N
1
967r 2 (12) (23) (34) (45) (51)x [812823 + 823834 + 834845 + 845851 + <:(1 , 2,3,4))'

where 8ij = 2li . lj and E(ijkm) = i4EILVp(7lrljl~lc:n.
Here, li are external gluon momenta. We also use thenotation for the spinor helicity basis (ij) = y'Sije iOij .
Here, (}ij is the phase factor 2 ) and N is the color factor(N = 3 for the QCD theory).
In these analyses, we also use computer programs
written by analytical manipulation programs , namely,
FORM and MAPLE. These programs are widely applicable to pQCD analysis. For example, we can apply
these programs immediately to processes which include
massless fermions (Ex; qq - t ggg, qq - t gg" etc). The
extension of these techniques and methods to theories
with a spontaneously broken symmetry such as theelectroweak theory is straightforward.
References

1) G. Bunce, N. Saito, J. Soffer, and W. Vogelsang:
hep-ph/0007218, ISSN 1344-3879, RIKEN-AF-NP-360,
and references therein.
2) Y. Yasui: Phys. Rev. D 61, 094502 (2000), and references therein.
3) M. Mangano and S. Parke: Phys. Rep. 200, 301 (1991),
and reference therein.
4) Z. Bern and D. A . Kosower: Phys. Rev. Lett. 66 1669
(1991); Nucl. Phys. B 379, 451 (1992).
5) Z. Bern, L. Dixon, and D. A. Kosower: Phys. Rev. Lett.
70, 2677 (1993).

265

RI KEN Accel. Prog. Rep. 34 (2001)

Single Spin Asymmetries in Inclusive Hadronic Reactions
Y. Koike and Y. Kanazawa*
Single transverse-spin asymmetries for large PT pion
production in PP collisions have been receiving considerable attention since the large asymmetry wasreported by the FNAL E704 group. I) An ongoingexperiment at RHle is expected to provide moredata on the asymmetry. The process probes particular quark-gluon correlations (higher twist effect)in the nucleon not included in twist-2 parton densities. According to the generalized QeD factorization theorem,2) the polarized cross section for thisprocess consists of three types of twist-3 cross sections: (A) Ga(x~ , x~) ® qb(X) ® DC->7r( z ) ® aab->c,(B) 8qa(x') ® Eb(XI, X2) ® D C->7r(z) ® a-~b -->c' and (e)8qa(X') ® qb(X) ® D~~7r(ZI ,z2 ) ® a~b->c ' Here, the functions Ga(x~ ,x~), E b(XI,X2) and D~~7r( ZI,Z2 ) are thetwist-3 quantities representing, respectively, the transversely polarized distribution , the unpolarized distribution, and the fragmentation function for the pion,
and a , band c stand for the parton's species. Other
functions are twist-2 quantities; qb(X) the unpolarized distribution (quark or gluon), 8qa( x) the transversity distribution, and DC-->7r (z) the fragmentation function for the pion. The symbol ® denotes convolution.
a ab-->c etc. represents the partonic cross section for theprocess a + b -+ c + anything which yields large transverse momentum of parton c. Note that 8qa , Eb andD~~ 7r are chiral-odd.
Qiu and Sterman 3 ) reported on a systematic QeD
analysis of the chiral-even contribution (above (A)).
They showed that the (A) term dominates the crosssection at large XF, i. e., pion production in the forward direction with respect to the polarized nucleon
beam. Within the valence quark-soft gluon approximation and a model assumption for the valence twist-3
distribution G a , they reproduced the E704 data reasonably well. In a recent paper,4) we extended theanalysis to one of the chiral-odd contributions ((B)term) and presented a cross-section formula. We also
discussed the possibility that this term could be a large
source of the asymmetry at large negative x F in parallel with the argument for the chiral-even contribution.
It turns out , however, that the (B) term is negligible inall kinematic region due to the smallness of the hardcross section, even though the unpolarized twist-3 distribution Eb receives a significant enhancement. 5)
There is another chiral-odd contribution ((e) term)
to the asymmetry. In this term, 8qa(x') and D~~ 7r canform a closed Fermion loop in the Feynman diagram;
therefore , there is no apparent reason for the corre-

Department of Physics, Niigata University

266

sponding hard cross section to be suppressed unlike
the case for the (B) term. In addition, the (e) term
receives the contribution from the gluon distribution.
It is expected to give rise to a large asymmetry at large
x F -+ 1 as in the case for the (A) term. The analysisof this term is under way.
It is also a well-known experimental fact that hyperons produced in unpolarized nucleon-nucleon collisions are polarized transversely to the production
plane. 6 ) This is also a twist-3 process and its crosssection consists of two types of twist-3 cross section:(D) Ea(XI) X2) ® qb(X') ® 8qc->Y( z ) ® aab->c, and (E)qa(x) ® qb(X') ® G~~y(ZI' Z2 ) ® a-~b-->c' Here, the newfunctions G~~y( ZI' Z2) and 8qc->y(z) are the twist-3
fragmentation function and the transversity fragmentation function for the transversely polarized hyperon,respectively.
In our recent analysis ,7) we presented a cross-section
formula for the (D) contribution and estimated its
magnitude, following the valence quark-soft gluon
approximation. 3 - 5 ) As expected, it gives rise to a large
hyperon polarization at large x F comparable to the experimental data. 6 ) Anselmino et al. analyzed the sameprocess under the assumption that the spin effect in
the fragmentation process (similar to the (E) contribution) is the sole origin of the hyperon polarization. 8 )Our analysis shows that (D) should also be considered
to fully account for the polarization.
References
1) D. L. Adams et al.: Phys Lett . B 261,201 (1991); Phys.
Lett. B 264, 462 (1991) ; A. Bravar et al.: Phys. Rev.
Lett. 77, 2626 (1996).
2) J. C. Collins, D. E. Soper, and C. Sterman:
in Perturbative Quantum Chromodynamics, edited by
A. H. Mueller, (World Scientific, Sihgapore, 1989), p.1;
J. Qiu and C. Sterman: Nucl. Phys. B 353, 137 (1991).
3) J. Qiu and G. Sterman: Phys. Rev. D 59 , 014004 (1999).
4) Y. Kanazawa and Y. Koike: Phys. Lett. B 478, 121(2000) .
5) Y. Kanazawa and Y. Koike: Phys. Lett. B 490 , 99
(2000) .
6) G. Bunce et al.: Phys. Rev. Lett. 36, 1113 (1976); K.
Heller et al.: Phys. Rev. Lett. 41, 607 (1978); E. J.
Ramberg et al.: Phys. Lett. B 338 , 403 (1994); P. M.
Ho et al.: Phys. Rev. Lett. 65 , 1713 (1990); A. Morelos
et al.: Phys. Rev. Lett. 71 , 2172 (1993).
7) Y. Kanazawa and Y. Koike: hep-ph/0012225.
8) M. Anselmino, D. Boer, U. D 'Alesio, and F . Murgia:
hep-ph/0008186.

RIKEN Accel. Prog. Rep. 34 (2001)

Gluon Distribution in the Real Photon
M. Imoto*l and F. Kawane*2
The structure function of a photon has been investigated via deep inelastic electron-photon (e - 1')
scattering. Experimentally, information regarding thisfunction is extracted from the process (e+ e- -+ e+ ehadrons). The parton distributions of the photon consist of contributions corresponding to a hadron-partand a point-part of the photon. The hadron-part ofthe parton distributions for low Q2 ::; 1 Ge y2 are represented by the nonperturbative model. The distributions for low Q2 evolve according to the next-to-Ieading
order Dokshitzer, Gribov, Lipatov, Altarelli and Parisi(NLO-DGLAP) equations. Also, the photon structure
function is sensitive to the gluon distribution only at
small x , so the shape of the gluon distribution should
be determined from data at small x. In Ref. 1, thevector meson dominance model (YMD) is assumed forthe photonic input distributions, and the approximate
similarity of the vector meson and the pion is utilized.
For the photonic input distributions f 'Y = q'Y (= q-'Y ),G'Y , we take f'Y(x , q6) =f7r (x,Q6), where the inclusion of the wand 'P mesons in addition to the p isindicated by the value of /'i,. In the valence quark distribution, Regge behavior amplitude is used at small
x. However, we express the input distributions of thegluon and the sea quark in the Pomeron exchange cut
rather than the Pomeron exchange as follows,

10~-11------------"""""'~--___1

~

10- 1

10-3

10- 1

x

Fig. 1. Small-x behavior for xC (x) at Q2 = 100 Ge y2. The
solid curve is our result with K, = 1.0 and the dashedcurve is our result with K, = 1.6.

2/'i,7fXl - a ce D) )xG(x) = b ( In(l/x)(1 - X)3 ,Xl-a ce D) )X((X) =c ( In(l/x)

Fig. 2. Prediction for xG(x) at Q2 = 75 Gey2 with HERA(HI) measurements.

(1- X)5 ,where ac(t) = {ap(t) +ap(t) -I} gives the position of
the branch point trajectory. Taking ap(O) ~ 1.08, we
observe Lipatov behavior 2) x-A. The l/ln(l/x) termarises from the integral over the phase between the two
Pomeron-Pomeron poles. Therefore, using Pomeroncut exchange, we represent the situation where many
soft gluon emissions appear at small x and the rise insmall x is generated as a result. Also, the O( Q2) term
for the point-like parts of parton distributions is introduced in the framework of NLO-DGLAP equation.
Using the above distributions we have shown l ) thatpredictions for the photon structure function are consistent with experimental data3 ) in OPAL at small x.
Here, this approach is used in order to investigate thebehavior of gluon distribution. In Fig. 1, the x dependence of xG(x, Q2) is shown at Q2 = 100 Gey2. The
solid curve is our result enhanced by a factor /'i, = 1.0,
and the dashed curve is enhanced by /'i, = 1.6 for the*1 College of Science and Technology, Nihon University*2 Junior College Funabashi Campus, Nihon University

photonic input distributions at Q6. Our result with/'i, = 1.6 approaches the Gluck, Reya and Vogt (GRV)
predictions 4) (/'i, = 1.6), which are steep in the small x
region. Thus we can say that the hadronic component
is dominant at very small x. In Fig. 2, we compare
the x dependence of our gluon distribution with HI
measurements. 5 ) Our result is similar to the gluon of
SaS 1D 6 ) and shows the flatter small-x behaviour compared to GRV.4)
References
1) M. Imoto, H. Kan, and T. Kikuchi: Prog. Theor. Phys.
102, 819 (1999) .
2) L. N. Lipatov: SOy. J. Phys. 23, 338 (1976); E. A.
Kuraev , L. N. Lipatov, and Y. S. Fadin: SOy. Phys.
JETP 45, 199 (1977); Y. Balitskii and L. N. Lipatov:SOy. J. Nucl. Phys. 28,822 (1978).
3) OPAL Collab., K. Ackerstaff et al.: Phys. Lett. B 412,
225 (1997).
4) M. Gluck and E. Reya: Phys. Rev. D 26, 2749 (1983);
M. Gluck, E. Reya, and A. Yogt: Phys. Rev. D 46, 1973
(1992).
5) HI Collaboration, T. Ahmed et al.: Nucl. Phys. B 445,
195 (1995).
6) G. A. Schuler and T. Sjostrand: Z. Phys. C 68, 607(1995).

267

RIKEN Accel. Prog. Rep. 34 (2001)

Semi-inclusive A c+ Production in Polarized ep Reaction
with Polarized Gluons
S. Oyama,*l H.-W. Huang,*2 and T. Morii
To understand the spin structure of a nucleon inquantum chromo dynamics (QCD), it is very important to obtain information on the polarized gluon distribution. Although thus far we have good knowledgeof polarized quarks based on the data from numerous polarized experiments and detailed QCD calculations, information on polarized gluons is still lacking.
High-energy polarized experiments which are planned,
for instance, at eRHIC, are expected to be useful forstudying polarized gluons.
To investigate the behavior of polarized gluon~, we
propose a new semi-inclusive process eiJ ~ eAt X,
which can be studied in the forthcoming eRHIC experiment and is very useful for studying polarized gluons.
At consists of u, d and c quarks in a naive quark model,
in which the spin wave functions of u and d quarks are
antisymmetrically combined and then the spin of At
is the same as that of the c quark. Therefore, we can
expect that the spin of At largely depends on that of
the c quark in the hard process. Furthermore, the cquark is produced with a c by boson-gluon fusion in
the lowest order of QCD. Therefore, one expects that
this process can provide rich information on the polarized gluon in the proton. By assuming the helicity ofthe produced c quark is preserved by hadronizing thec quark to At, we calculated the spin-dependent differential cross section in the lowest order of QeD foreiJ ~ eAt X and the two-spin correlation asymmetry,d(J++ - d(J+ _ + d(J __ - d(J_+d(J++ + d(J+_ + d(J __ + d(J_+ALL = --~----~-------------­_ d~(J/dydz- d(J /dydz 'where d(J +_ is the spin-dependent differential crosssection for the proton with a positive helicity and theAt with a negative one, and y and z are dimensionlessvariables used in semi-inclusive deep inelastic scattering. In this calculation, we used the typical parameterization models of the polarized gluon distribution,
namely, GS96 set(A)l) and GRSV96 ,2) together withthe unpolarized model of GRV95. 3 )The case of the photon-gluon fusion was calculated

*1

*2

268

Graduate School of Science and Technology, Kobe University
Faculty of Human Development, Kobe University

0.25 .-----.----,-----,,-----.----r--.-- ,..9-6........,----_-r~GS
GRSV96 ............
0.2

O~1.~

' \ •.• ,

0.05

o

L-~~

__~~__~~__~~~___

o 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 O.g
Y

Fig. 1. Two-spin correlation asymmetry, ALL, between thepolarized proton and At at Js = 100 GeV and z = O.l.
The solid and dashed curves indicate GS96 set(A) and
GRSV96, respectively.

before at VB = 50 GeV.4 ) Here, we took into accountthe Zo interaction as well as the photon interaction,
foreseeing high energy polarized experiments.
Figure 1 shows the calculated result of the two-spincorrelation asymmetry, ALL, between the polarized
proton and the produced At at VB = 100 GeV andz = 0.1, whose energy is planned in the future eRHIC
experiment. In Fig. 1, it is evident that the asymmetry
largely depends on the models of the polarized gluon
distribution in some kinematical region, i.e., the asymmetry is sensitive to the models of the polarized gluon
distribution. Therefore, the process we propose here
could be useful in testing the models of the polarized
gluon distribution, thus providing rich information on
the structure of the proton.
References
1) T. Gehrmann and W. J. Stirling: Phys. Rev. D 53, 6100
(1996).
2) M. Gliick, E. Reya, M. Stratmann, and W. Vogelsang:
Phys. Rev. D 53, 4775 (1996).
3) M. Gliick, E . Reya, and A. Vogt: Z. Phys. C 67, 433(1995).
4) N.1. Kochelev, T. Morii, and S. Oyama: RIKEN Accel.
Prog. Rep. 33, 35 (2000).

RIKEN Accel. Prog. Rep. 34 (2001)

Single Diffractive At Productions at Relative Heavy Ion Collider:
A Test of Hard Diffractive Factorization and Polarized Gluon
Distribution Function
K. Ohkuma*l and T. Morii*1,*2
Studing the nature of a pomeron which plays a crucial role in diffractive scattering remains a challenging topic. To understand the diffractive process in theframework of Quantum Chromodynamics (QCD), Ingelman and Schlein suggested 1) that by assuming thatthe pomeron has a partonic structure, the observablesof the diffractive process can be calculated by a hard
diffractive factorization approach, i. e., the diffractive
structure function is given in the factorized form of
the pomeron flux and the pomeron structure function. However, the predicted cross sections by the hard
diffractive factorization approach for hadron-hadroncollisions are several times larger than the experimental data. 2) In order to overcome such inconsistency,
Goulianos proposed a phenomenological model. 2) In
this model, he introduced a renormalized pomeron flux
factor which is generated by renormalizing the stan-

dard pomeron flux in a proton to be unity (renormalized pomeron flux model). 2) Further tests using thismodel for various processes are interesting.
The RHIC experiment will commence soon. One of
the important objectives of this experiment is to extract information about the polarized gluon distribution in the proton. The obtained information will be
the key to understand the proton spin puzzle. Thusfar, there are many models which can excellently reproduce experimental data on the polarized structure
function of nucleons. However, the behavior of polarized gluons are quite different among those models. It
is interesting to test the models of the polarized gluon
distribution in the forthcoming RHIC experiments.
In this work, to test the hard diffractive factorization and polarized gluon distribution model, we propose another diffractive semi-inclusive process: p+p---+- - GRV95----- GS96-A---- GS96-B
0.06 r--..-,-..-,-..-r--"'''---''-- _____ GRSV96-

Gs96-A
10' .,...-.--,.--.--,.--r----"'r--"'''---''-- ----____ GS96-B----- GRSV96

,,

...

0.04

,

\
\\
0.02
\\
"', \ \
\ \\
'''\

:::l

0

~

\\\

-0.02

10-4

-0.04

3

5

7

9

11

13

15

-0.06 ~~~~~~~~~~~~~~
1
3
7
11
13
15
5
9
[GeV]

[GeV]

Fig. 1. The unpolarized and polarized differential cross sections (left panel) and the spin-correlation
asymmetry (right panel) as a function of PT at Vs = 500 GeV. The solid line in the left panel
represents the unpolarized differential cross section with the GRV95 model for the unpolarized gluon
distribution. The dashed, long-dashed and dot-dashed lines indicate the polarized differential crosssection calculated using the sets A and B of the GS96 model and the GRSV96 model, respectively,
is negative for PT and is. larger than the value
for the polarized gluon distribution. The value of ~~O"P
corresponding to the apparent sharp dip.
*1

*2

T

Graduate School of Science and Technology, Kobe University
Faculty of Human Development, Kobe University269

At + X. We have already analyzed this process in
the large PT region with interesting results. 3 )In this process, we calculated the spin-correlationdifferential cross section, d~O' / dp T using the renormalized pomeron flux model and the spin-correlation
asymmetry, ALL, defined byP+

d~O' _ dO'++ ---dO'+_ + dO' __ - dO'_+

dp T

dPT
- [dO'++ - dO'+_ + dO' __ - dO'-+l /dpT
A LL - [dO'++ + dO'+_ + dO' __ + dO'-+l /dP T_ d~O'/dpT= dO' /dP T 'where dO'+_ denotes the spin-dependent differential
cross section with the positive helicity of the target
proton and the negative helicity of the produced At .
d(~)O'/dpT and ALL will be measured in the forthcoming RHIC experiment . To calculate d~O' / dp T and
45
ALL , we used the GS96 ) and GRSV96 ) parameterization models for the polarized gluon distribution function and the GRSV95 6 ) model for the unpolarized one.

270

The PT distribution of d(~)O'/dpT and

ALL

for

VB = 500 GeV are shown in Fig. 1. As shown here,d~O' / dPT and ALL are sensitive to the polarized gluon
distribution functions. Note that if the renomalized
pomeron flux model is not taken into account in thepresent process , the polarized diffential and the unpolarized diffential cross sections become several times
larger than our calculation. This means that measuring these observables can be a test of the renormalized
pomeron flux model. Therefore, the process might beeffective for testing not only the hard diffractive factorization but also the polarized gluon distribution function.

References
1) G. Ingelman and P. E. Schlein: Phys. Lett. B 152 , 256(1985).
2) K. Goulianos: Phys. Lett. B 358, 379 (1995).
3) K . Ohkuma, K. Sudoh, and T. Morii: hep-ph/0009004.
4) T. Gehrmann et al.: Phys. Rev. D 53, 6100 (1996).
5) M. Gluck et al.: Phys. Rev. D 53 , 4775 (1996).
6) M . Gluck et al.: Z. Phys. C 67, 433 (1995).

RIKEN Accel. Prog. Rep. 34 (2001)

Polarized s-Quark Distribution in Semi-Inclusive A~ (A~) Production
K. Sudoh*
The proton spin puzzle is currently one of the mostchallenging topics in high-energy spin physics. As iswell known, a proton spin is composed of the spins
and the orbital angular momenta of quarks and gluons
which constitute a proton. The polarized parton distribution function plays an important role in an in-depth
description of the spin structure of a proton. However,the polarized sea quark distribution functions remain
now poorly clarified.
Recently, the HERMES group has reported that direct measurement of the strange sea is required to explain the violation of the Ellis-Jaffe sum rule.I) However, we do not have sufficient knowledge to determine
the polarized sea quark distribution. Here, I focus on
the polarized s or B quark distribution.
In this work, to examine the polarized s (B) quark
distribution, I studied semi-inclusive At and At leptoproduction, e+ + p --+ De + At + X and e- + p--+Ve

+ K; + X, in unpolarized lepton-polarized proton

collisions which might be observed in the forthcoming experiments at e-RHIC or TESLA-N, where thearrow attached to particles indicates that these particles are polarized. In the naive quark model, since theAt baryon is composed of a heavy c-quark and antisymmetrically combined light u- and d-quarks, we canassume that the polarization of the At baryon is thepolarization of the c-quark. In addition, At (At) is
dominantly produced by the fragmentation of c (c)quark which is produced by s (B)-quark through thet-channel W exchange in the leading order. Hence we
can expect that measurement of the produced At polarization will provide information about the polarizeds-quark distribution in a proton.
In these processes, I calculated the double spin
asymmetry ALL defined by

ALL(PT) =db.,CJ jdPT
dCJ jdPT '

(1)

where

For instance, in the At production, the spin-dependent
differential cross section generally has a form,

db.,CJ(At) = {U~sb.,s(x) + U~db.,d(x)} dx
x (d~a) di.t.D~;; (z)dz,(2)

where b.,s(x) and b.,d(x) are polarized s-quark andd-quark distribution functions, respectively. Here, I
Graduate School of Science and Technology, Kobe University",IiISOGeV', =lOOGoV~ L-----_

~

.....

0,3

0.2

_________'-----",~~

0,3.....~ 0,2---------------"°2~~--~,2-~-~~

P,

PT

[Goy]

[GoY]

Fig. 1. Double spin asymmetry in e+ +fJ --+ De+At +X as afunction of PT at ys = 50 GeV (left) and ys = 100 Ge V
(right). Solid and dashed lines represent the "standard
scenario" of GRSV96 and set A of GS96, respectively.
-oos_

-0_

0,6

- - - GSH-A- - - GS96-A',.SOGoV

I~

0.'

~

0,2

.J,.l00GtV

,..

.....

0.3

1..(

.e.

.eo

0

~

.....

2

------------------------ ----

0

12

7

P,

02

[Goy]

2

-------22

PT

[Goy]

Fig. 2. Double spin asymmetry in e- +iJ --+ l/e+K~ +X as afunction of PT at ys = 50 GeV (left) and ys = 100 Ge V
(right). Lines indicate the same cases as in Fig. 1.
used the GS96 2) (set A) and GRSV96 3) ("standard
scenario") parameterizations for the polarized parton-+

distribution. b.,D~c (z) is the polarized fragmentation
function and I used the Peterson model,4) assumingb.,D~-: (z) ~ D~-: (z).
The PT distribution of ALL in the At production
and the At production at center-of-mass energy VB =50- 100GeV are shown in Fig. 1 and Fig. 2, respectively. As shown in the figures, ALL in the At production largely depends on the models of the polarized
parton distribution function, and significant differences
can be observed among them. Therefore, I conclude
that measuring the double spin asymmetry in this process is very effective not only for testing the model ofthe parton distribution function but also for extracting
the polarized strange sea distribution clearly. On theother hand, for At production we cannot determine
the s-quark distribution clearly, since the contribution
from the valence d-quark is large.
References
1) HERMES collaboration: Phys. Lett. B 464, 123 (1999).
2) T. Gehrmann and W. J. Stirling: Phys. Rev. D 53, 6100
(1996).
3) M. Gluck et al.: Phys. Rev. D 53, 4775 (1996).
4) C. Peterson et al.: Phys. Rev. D 27, 105 (1983).

271

RIKEN Accel. Prog. Rep. 34 (2001)

Polarized Gluon Distributions from High-PT Pair
Charmed Hadron Leptoproductions
Y.-B. Dong,*l T. Morii,*2 and T. Yamanishi*3
Recently, new parametrization sets of the polarized parton distribution functions (pol-PDFs) were obtained from the fitting of polarized deep inelastic scattering (pol-DIS) with high precision for various targets
to experimental data. 1 ) However, knowledge of the behavior of polarized sea quarks and gluons is still limited
because it is difficult to directly obtain such information. Thus far, some interesting proposals for studying longitudinally polarized distributions of sea quarks
and gluons have been presented. 2,3) For the measurement of the polarized sea quark distribution, several researchers suggest the use of Drell-Yan processes,2) wboson productions and the semi-inclusive processes3)
in polarized experiments. For the polarized gluon
distribution, some interesting processes are also proposed: direct prompt photon production in polarized
proton-polarized proton collisions, open charm andJ /'I/J-pair production 4 ) in polarized lepton scatteringoff- polarized nucleon targets. Recently, the HERMES
group at DESY reported the first measurement of thepolarized gluon distribution by di-jet analysis of semiinclusive processes in pol-DIS, although only one data
point is given as a function of Bjorken x. 5 )Here, we extend the di-jet analysis of semi-inclusive
processes for any hadron pair productions to thecharmed hadron pair production in order to obtain accurate information on the polarized gluon distribution
in the nucleon . In general, the high-PT hadron pair
production is given by photon-gluon fusion (PGF) andQeD compton at the lowest order of QeD (Fig. 1).
The PGF gives us direct information on the polarized
gluon distribution in the nucleon, while QeD compton
becomes a background to the signal process for extracting the polarized gluon distribution. Here, we consider
charmed hadron pair production as the high-PT hadron
~
//

Q

/

t.Q

----------~./ ., 'I: --~==e(a)

( -)

g

OJ

h

pphoton-gluon fusion==:(' 'ii'p(b)

QeD compton

Fig. 1. Lowest-order Feynman diagrams for the high-PT
pair hadron production.
*1

*2

*3

272

Institute of High Energy Physics, Academia Sinica, China
Faculty of Human Development, Kobe University
Department of Management Science, Fukui University ofTechnology

pair production since we can safely neglect the contributions of the QeD compton process for heavy-quark
pair productions.
The double-spin asymmetry for a process of ,* +N ~ he + he + X is described asd!:::.O'
dO'_+ - dO'++(1)
A LL - dO'_+ + dO'++
dO"
where dO' _+ denotes the cross section for the leptonand nucleon with negative and positive helicities, respectively. The polarized differential cross section canbe calculated by

r

1

3

r

1

3

d !:::.O' = !:::.g(ry Q2)d6
d6 d !:::.adrydz 1 dZ2' J Z l 6 }Z 2 6 drydzedz ex 1)~c (~1)1)~c (~2) '

(2)

where

s

ry = -s ,p. P1
Zl = - p
.q ,

p. P2
Z2 = - P.q 'and at the partonic level,
P . PqZl
P . Pii
Z2
Ze = - = -6 , Ze = - = -.
p.q
p.q
6

(3)

(4)

In Eq. (2), !:::.g and 1)~te~hc) denote the longitudinallypolarized gluon distribution and fragmentation functions from a charmed quark to a charmed hadron,respectively. Here, we take the 1)*+- meson as thecharmed hadron because its fragmentation function
has been recently studied extensively.6)
In the future , we plan to numerically calculate thedifferential cross section given in Eq. (2) using various
parametrization models of the polarized gluon distribution function and to estimate the sensitivity of thisprocess on the polarized gluon.
References

1) L. E . Gordon , M. Goshtasbpour, and G . P. Ramsey:
Phys. Rev . D 58, 094017 (1998) ; G. P. Ramsey: Prog.
Part. Nucl. Phys. 39, 599 (1997) ; E. Leader, A. V.
Sidrov, and D. B. Stamenov: Phys. Rev. D 58 , 114028(1998); Phys. Lett. B 445, 232 (1998) ; Phys. Lett. B
462, 189 (1999) ; Y. Goto and Asymmetry Analysis Collaboration: Phys. Rev. D 62, 034017 (2000).
2) S. Hino and S. Kumano: Phys. Rev . D 59, 094026(1999); Phys. Rev. D 60, 054018 (1999) ; S. Kumano
and M. Miyama: Phys. Lett. B 479, 149 (2000).
3) T. Morii and T. Yamanishi: Phys. Rev. D 6 1, 057501(2000); Phys . Rev. D 62 , 059901 (2000).
4) A. Bravar, D . von Harrach, and A. Kotzinian : Phys.
Lett . B 421, 349 (1998).
5) A. Airapetian et al.: HERMES Collaboration, Phys.
Rev. Lett. 84, 2584 (2000).
6) J . Binnewies, B. A. Kniehl , and G . Kramer: Phys. Rev .
D 58 , 014014 (1998).

RIKEN Accel. Prog. Rep. 34 (2001)

Chiral Properties of Domain-Wall Quarks in Quenched QCD
Y. AokiNumerical simulation with lattice gauge theory is
a powerful nonperturbative tool for analyzing QCD.
It respects the gauge symmetry, which is one of themost important aspects of QCD. Another is the chiralsymmetry, which has not been satisfactory realized.
Against this long-standing problem of lattice gauge
theory, the domain-wall fermion l - 3 ) was proposed with
fascinating features. It is a five-dimensional Wilson fermion variant, characterized by the system length in thefifth direction Ns and the domain-wall height M. The
four-dimensional physical fermions are defined in termsof those fermions on the five dimensional boundaries.
Analytical studies have shown that this model has
the exact chiral symmetry in the limit Ns ~ (X)even at finite lattice spacings. Here we test it 4 ) nonperturbatively for QCD in the quenched approximation, where most of the applications have been done.
We focus on the anomalous quark mass, m5q , which
is defined through the symmetry-breaking term of
the pseudoscalar channel of the axialvector WardTakahashi identity. This quantity can be interpreted as
the additive correction of the fermion mass , and is expected to vanish in the limit Ns~(X) as m5 q rv e - f,N s .2)
We investigate two types of gluon action; one is theordinary Wilson plaquette action and the o~her is therenormalization group improved action (RG action) of
Iwasaki type, which, with the ordinary fermions , leads
to much better scaling toward the continuum limit
than the plaquette action. We expect that this improved scaling also affects the chiral properties.
Two lattice spacings, a = 0.1 and 0.2 fm , were
investigated in this study. While a wide range ofdomain-wall heights, 1.3 :::; M :::; 2.5, was surveyed for
a = 0.2 fm, we show the set of results at M = 1.7 as a
typical example. The domain-wall height at a = 0.1 fm
was fixed to M = 1.8.
In Fig. 1 we show the results of anomalous quark
mass. For the same action, one obtains better chiral properties with finer lattices. For the same latticespacing, the improved action yields better results. One
important practical suggestion here is that one should

10'

b) RG

(16'~~;Nj10'10'• 8=0.2 fm
0 8=0.2 fm (12' x24XNJ.8=0.1 fm (16' x32xNJ- fil with c+ae·~·--- mwithae· ~·

10'

30

30

N,

N,

Fig. 1. Anomalous quark mass m 5 q as a function of theextent of the fifth direction Ns for plaquette action a)and RG action b).

employ improved gauge action such as RG action to
reduce the amount of computation.
Let us examine the Ns dependence at a = 0.2 fm
for the plaquette action. The anomalous quark massdecreases as the length of the fifth direction Ns increases. However it does not decrease as fast as e-f,Ns ,but rather as c + ae-f,Ns with c > O. This implies
that the chiral symmetry is not realized in the infinite
Ns limit. This is also true for all other cases except
for a = 0.1 fm with RG action, for which the simple
exponential fit reproduces the data quite well. These
results indicate that the domain-wall fermion fails to
realize chiral symmetry in quenched QCD for at leasta 2:: 0.1 fm with the plaquette action and a 2:: 0.2 fm
with the RG action.
There are two other studies available for the anomalous quark mass at a = 0.1 for the plaquette action.
The authors of Ref. 5 have studied it for 4 :::; Ns :::; 10.
Our results are in very good agreement with theirs. We
can find the results for 12 :::; Ns :::; 48 in a recent paperby the RIKEN-BNL-Columbia collaboration. 6 ) Theirdata are consistent with ours , in the region where bothof them can be compared, but their point at Ns = 48
shows a tendency to decrease still more. Further study
is needed to clarify this difference.
We remain interested in the qualitative difference of
the anomalous quark mass for two actions and thatfor different lattice spacings. One way to further investigate this subject is to study the eigenvalues ofthe four-dimensional Wilson-Dirac operator, 7 ,8) whose
zero mode has one-to-one correspondence to the unittransfer matrix of the domain-wall fermion system inthe fifth direction. This might be also a good means
for the clarification of the large Ns behavior of m5q at
a = 0.1 fm for the plaquette action.
This report is a summary of works done in the CPPACS collaboration.
References
1) D. Kaplan: Phys. Lett. B 288, 342 (1992); Y. Shamir:
Nucl. Phys. B 406, 90 (1993).
2) V. Furman and Y. Shamir: Nucl. Phys. B 439, 54(1995).
3) For a review for the application of the domain-wall
fermion to QCD, see, T. Blum: Nucl. Phys. B Proc.
Suppl. 73, 167 (1999) .
4) CP-PACS Collaboration, A. Ali Khan et al.: hep-latj
0007014, to appear in Phys. Rev. D.
5) S. Aoki et al.: Phys. Rev. D 62, 094502 (2000).
6) T. Blum et al.: hep-latj0007038.
7) R. Edwards et al.: Phys. Rev. D 60, 034502 (1999).
8) CP-PACS Collaboration, A. Ali Khan et al.: hep-latj
0011032, to appear in Nuc. Phys. Proc. Suppl.

273

RIKEN Accel. Prog. Rep. 34 (2001)

Diquark Correlations and Flavor Dependence of Quark Distributions
H. Mineo,*l W. Bentz,*2 and K. Yazaki*3
The valence (v) quark distributions extracted fromexperimental nucleon structure functions show thatd v (x) is softer than U v (x).
This feature can be
explained l ) as an effect of diquark correlations in thescalar (J = 0) channel. We investigated 2) the role of
the axial vector (J = 1) channel as well, using the relativistic Faddeev approach to the Nambu-Jona-Lasiniomodel and the 'static approximation' of the quark exchange kernel. 3) We consider the three cases shownin Table 1 with different interaction strengths (r a) in
the J = 1 channel, fitting the interaction strength in
the J = 0 channel (r s) to the experimental nucleon
mass in each case. (The constituent quark mass is
M = 400 Me V). The resulting values for the scalar diquark mass (Ms) and the contribution of the scalar
channel to the baryon number (Ws) show that cases I
and III correspond to strong and weak J = 0 correlations, respectively. The ratio of the structure functions
F:; / Ff shown in Fig. 1 clearly indicates that the correlations in the J = 1 channel should not be too strong(Wa < 10%). Case II gives a reasonable description of
Table 1. Parameter sets used in the calculation and resulting values for Ms and Ws.
case
ra
rs
Ms [MeV]

Ws[%]

*1

*2

*3

274

0
0.73
600
100

II

III

0.25
0.63
684
90

0.66
0.50
766
60

Department of Physics, University of Tokyo
Department of Physics, Tokai University
College of Arts and Sciences, Tokyo Woman's Christian University

F1"/F:
I~--~----~---.----~--~----~--~~

u

CASEm

0.1

I

0.'

0 ..

UO-----~·,----U~---U~--~~----~U-----U~---&~7~
X

Fig. 1. Ratio of structure functions F:; / Ff for three casesof Table 1.

the valence quark distributions. These results, as wellas the static properties of the nucleon for the above
three cases and the effects of the pion cloud, will be
published soon. 2)
References
1) F. E. Close and A. W. Thomas: Phys. Lett. B 312, 227(1988).
2) H. Mineo, W. Bentz, and K. Yazaki: to be published.
3) H. Mineo, W. Bentz, and K. Yazaki: Phys. Rev. C 60,
065201 (1999).

RIKEN Accel. Prog. Rep. 34 (2001)

Renormalization Group Approach to the O(N) Linear Sigma
Model at Finite Temperature
K. Naito, T. Umekawa,* and M. Oka*
The Wilsonian renormalization group (RG) method
is applied to finite temperature systems for the studyof nonperturbative methods in the field theory. I) We
choose the O(N) linear sigma model as the first step.
Under the local potential approximation, we solve theWilsonian RG equation numerically as a nonlinear partial differential equation. The evolution of the domain
is taken into account using the simple cut and extrapolation procedure. The obtained effective potential isshown in Fig. 1. Our procedure is shown to yield thecorrect solution obtained by the auxiliary field methodin the large N limit. To include thermal effects, weemploy the imaginary time formalism. In our method,
the sum of the Matsubara frequencies is taken before
the scale is introduced. Then, the RG equation in thisscheme readsalit)

dllt(x) = ADAD {(N -1) In (1 + ~~dt
2A2 x ax

0.01 ,...--,.---.---.---.---.--.---.---.--.--.--:-,r.-,--.-.,...,..--,---r--..

//

i""
I""

0.008
0.006
0.004
Q002

j' ....

/ ....
//........-;.:::-:::-.. -.--:_/=~-'-..-...- - -+ - --0.004-0.006-0.008-0.01 0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

q,
Fig. 1. Effective Potential at the scale A = 1.0 (solid) ,exp( -0.5) (dotted), exp( -10.0) (dash-dotted) respectively.

0.08

0.06
II>

0.04

0.02

The temperature dependence of the condensate 1>
is shown in Fig. 2. We observe a second-order phasetransition. The critical exponents are calculated in
the Table 1 and are shown to agree with the world
best value. However, our approach has some numericalunstabilities. Further improvements are necessary.

(3
0.38
0.384

8
4.7
4.85

T

Fig. 2. The temperature dependence of the condensate.

References
1) T. Umekawa, K. Naito, and M. Oka: hep-ph/9905502.

Table 1. Critical exponents.

Our result
Monte-Carlo 2 )o2) K. Kanaya and S. Kaya: Phys. Rev. D 51 , 2404 (1995).

1.4
1.48

Tokyo Institute of Technology

275

RIKEN Accel. Prog. Rep. 34 (2001)

Chiral Condensates in a Light-Cone Vacuum
F. Lenz ,*l M. Thies,*l and K. Yazaki*2
The standard procedure to characterize the phasesof a system by appropriate ground-state expectation
values fails in light-cone quantization because of the"triviality" of the vacuum. 1 ,2) This poses conceptual
problems about the light-cone quantization in the nonperturbative regime,3) though its equivalence to more
standard quantizations has been established perturbatively.
We carefully examine the behaviors of the productsof field operators when their light-cone time coordinates are close to each other and demonstrate thatmeaningful quantities serving as order parameters are
obtained as expectation values of Heisenberg operatorsin the equal (light-cone) time limit. These quantities
differ from the purely kinematical expectation valuesof the corresponding Schroedinger operators, for which
the light-cone time coordinates of the field operators
are chosen to be the same from the beginning.
For the Nambu-Jona-Lasinio (NJL)4) and the GrossNeveu (GN)5) models, we apply the above procedure
to define the chiral condensates and describe the spontaneous breakdown of chiral symmetry by deriving the
gap equations and the values of the chiral condensateswithin the framework of light-cone quantization. In

*1

*2

276

Institute for Theoretical Physics III, University of Erlangen,Germany
College of Arts and Sciences, Tokyo Woman's Christian University

these models, dynamical time evolutions of the Heisenberg operators can be approximated by those of freefermions with constituent masses to the leading orderof liN expansion. 6 ) The results are found to be equivalent to those of more standard approaches.
We thus believe that the light-cone quantization has
no conceptual problem even in the nonperturbative
regime if the Heisenberg operators are used to define
the operators characterizing the nonperturbative features, and can provide us with a practical method ofstudying hadron structures and hadron spectra.
References
1) M. Burkardt: Adv. Nucl. Phys. 23, 1 (1996).
2) S. J. Brodsky, H.-C. Pauli, and S. S. Pinsky: Phys. Rep.
301 , 299 (1998).
3) K. Itakura and S. Maedan: Phys. Rev. D 61, 045009(2000).
4) Y. Nambu and G. Jona-Lasinio: Phys. Rev. 122, 345(1961); Phys. Rev. 124, 246 (1961).
5) D. J. Gross and A. Neveu: Phys. Rev. D 10, 3235
(1974).
6) W. Bentz, T. Hama, T. Matsuki, and K. Yazaki: Nucl.
Phys. A 651 , 143 (1999).

RIKEN Accel. Prog. Rep. 34 (2001)

K ~ 7r7r Decays with Domain Wall Fermions t
T. Blum
Recent measurements of direct C P violation (E' / E "#0) in K meson decays at FN AL and CERN allow
an important test of the Standard Model of particle physics, in particular, the Cabibbo-KobayashiMaskawa (CKM) mixing paradigm. The effective weak
Hamiltonian governing strangeness changing K decays
has been computed to next-to-Ieading order in QCD
and QED by the Munich and Rome groups.

H~S=l = V. V* G p
ud us

J2

[(1 + Vtd~~)
Vud Vt7s. (C1(P,)(Ql(P,) - Qlc(P,))+ C2(P,)(Q2(P,) - Q2c(P,)))-

T~d V.Vt: c(p,) . Q(p,)] ,
Vud

(1)

us

where Vij are the C K M matrix elements, Ci are
Wilson coefficients, and Qi are effective four quark operators. The C K M matrix elements are fundamental
parameters of the Standard Model, and the Wilson
coefficients have been computed in weak coupling perturbation theory. The remaining piece of the puzzle isthe computation of hadronic matrix elements of the operators of this effective weak Hamiltonian, (7r7r 1QilK).
These matrix elements are also needed for a first principles understanding of the empirical ~I = 1/2 rule ofkaon decays. The matrix elements must be computed .
nonperturbatively. The only viable first principles approach is lattice QCD.
In lattice QCD the recent advance of domain wall(and overlap) fermions which maintain chiral symmetry to a high degree of accuracy allows for a promising
new attempt at this long-standing problem. Chiralsymmetry of domain wall fermions provides a significant advantage when computing light quark QCD observables since the lattice artifacts that arise when thissymmetry is explicitly broken are greatly reduced.
The excellent chiral properties of domain wall
fermions allow a further simplification of the latticecalculation. We use lowest order chiral perturbation
theory to relate K ~ 7r7r matrix elements to a linear
combination of K ~ 7r and K ~ 10) matrix elements,
which are much easier to compute on the lattice. However, this simplification adds a systematic uncertainty

since final state interactions of the pions do not appear at lowest order in chiral perturbation theory. In
fact, present lattice methods can not treat these interactions.
In the past year we have completed three significant
quenched lattice QCD calculations using domain wall
fermions. In the first studyl) we precisely determined
the residual explicit chiral symmetry breaking effects ofdomain wall fermions in order that all of our domain
wall fermion calculations rest on a sound theoreticalfoundation. The results were quite satisfactory, andgave us confidence to proceed with the much more complicated matrix element calculations described above.
The second calculation 2 ) was a first study of operator renormalization using domain wall fermions andthe nonperturbative renormalization method of theRome-Southampton group. The use of this techniquewith domain wall fermions represents a significant advance over previous studies with conventional lattice
fermions. The renormalization of operators is an important aspect of all lattice matrix element calculations.
Finally, in our third study,3) we have completed thecomputation of all matrix elements of the effective
weak Hamiltonian in Eq. (1) needed to determine E' /E
and the ~I = 1/2 rule, as well as the corresponding operator renormalizations. The final results depend crucially on a complicated combination of all the matrix
elements of the operators appearing in Eq. (1) and theprecise removal of unphysical divergent terms arisingfrom the lattice regularization. There are many delicate cancelations from both procedures. Thus, greatcare must be taken in the final analysis to control statistical and systematic uncertainties. We are presently
in the final stages of this analysis.
References
1) T. Blum et al.: hep-lat/0007038, to be published inPhys. Rev. D.
2) C. Dawson: hep-Iat/OOll036; T. Blum et al.: submitted
to Phys. Rev. D, hep-lat/Ol02005.
3) T. Blum: hep-lat/00ll042 and R. Mawhinney: hep-lat/
0010030 for preliminary results.

This work was done in collaboration with N. Christ, C.
Cristian, C. Dawson, G. Fleming, X. Liao, G. Liu, S. Ohta,
A. Soni, P. Vranas, R. Mawhinney, M. Wingate, L. Wu, andY. Zhestkov. We thank RIKEN, BNL and the U. S. Department of Energy for providing the facilities essential for this
work

277

RIKEN Accel. Prog. Rep. 34 (2001)

QCDOC Super Computer for Lattice QCDt
D. Chen,*l N. Christ,*2 Z. Dong,*2 A. Gara, *l K. Garg,*2 B. JOO,*3 c. Kim,*2 L. Levkova,*2 X. Liao,*2
R. D. Mawhinney,* 2 S. Ohta,*4 T. Wettig,*5 and A. Yamaguchi*2
In the fall of 1998 the RIKEN-BNL Research Center (RBRC) completed a 500 Gflops "QCDSP" parallel
super computer in collaboration with Columbia University and Brookhaven National Laboratory (BNL).
It was awarded the Gordon-Bell Prize at the "Super Computing 98" international symposium in thesame year. A new "RIKEN-BNL-Columbia-KEK" lattice quantum chromodynamics (QCD) collaboration
has been very successfully using this computer and its
400 Gflops sister computer at Columbia University eversince. In particular the collaboration pioneered the application of the five-dimensional domain-wall fermion
method in lattice QCD. I ) To follow up, RIKEN,
Columbia University and IBM Research agreed to startanother collaboration to develop a new parallel computer for lattice QCD capable of 10 Tflops.2)
These QCDSP computers are constructed as fourdimensional hypercubic nearest-neighbor networks oftwelve thousand (at RBRC) and eight thousand (atColumbia) computing nodes.
Each node has a
50 Mflops DSP, 2 Mwords DRAM , and an application
specific integrated circuit (ASIC) of 250 K transistors
which provides an interface to the memory and eight
off-node communication ports.
In the machine now being designed , QCDOC (QCD
"On a Chip"), an entire node shrinks to fit in an ASIC
of about (1 cm)2 with 50 M transistors. A PowerPC
RISC integer processor and a 1 Gflops 54-bit IEEE
floating-point unit replace the DSP. Memory is expanded to 4 MBytes on chip, with possible extension
of up to 512 MBytes per node by adding a small,industry-standard, DIMM memory card.
Twelve,instead of eight, serial ports are each capable of
1 Gbit/sec off-node communication. They support a
six-instead of a four-dimensional network which can beeasily partitioned into five- or four-dimensional sublattices (see the example in Fig. 1).
The on-chip memory is joined to the processor witha very high bandwidth bus which provides a maximum data transfer rate between memory and processorof 8 Gbytes per second. This removes a troublesome
bottleneck in the QCDSP design and should permit
generic 'c' code to run with a reasonable efficiency on

*1

*2

*3
*4
*5

278

We thank RIKEN and the US Department of Energy
IBM T. J. Watson Research Center, Japan
Columbia University, USA
University of Kentucky, USA
Institute for Particle and Nuclear Studies, High-Energy Accelerator Research Organization (KEK)
Yale University, USA

Fig. 1. In this example a 4D hypercubic torus of 24 QCDOC nodes is partitioned into 6 x 2 (red) and 2 x 2(blue) 2D tori. Note a factor of 6 allows a flexible choiceof lattice sizes. Larger 6D networks will be even more
flexible. Periodic boundary conditions are understood.

the new QCDOC computer. In addition, each QCDOC
ASIC is equipped with an Ethernet controller and Ethernet access to JTAG debugging control. The Ethernet
controller will provide communications between eachnode and the host computer as well as access to disk
storage. An 8,192-node QCDOC machine will havean equal number of 100 Mbit/sec Ethernet ports, connected to provide a total possible bandwidth to disk
as large as 25 Gbytes/sec. The Ethernet-based JTAG
connection will permit Ethernet controlled booting aswell as a very powerful, multi-node debugging capability. We expect to achieve a cost performance for
QCDOC of less than $1 per sustained Mflops in construction and to consume only a couple of Watts per
node, making QCDOC about an order of magnitude
more cost effective than QCDSP in both its procurement and operation.
References
1) T. Blum et al.: hep-lat/0007038, to appear in Phys.
Rev. D; see also many contributions from the group in
recent "Lattice" series of international symposia, Nucl.
Phys. B Proc. Suppl.
2) D. Chen et al.: Proc. on Lattice 2000; hep-Iat/00l1004.

RIKEN Accel. Prog. Rep. 34 (2001)

String Tensions and Phase Structure of SU(4) Yang-Mills Theoryt
S. Ohta* l and M. Wingate*2
There are renewed interests in SU(Nc) pure YangMills theory with large (Nc ): (1) Finite-temperaturephase structure of quantum chromodynamics (QCD)
would be easier to understand if the SU(Nc ) pureYang-Mills system has a second order phase transition for Nc 2:: 4.1) (2) New developments in M/string
theory2) predict such things as glueball spectrum atlarge Nc and large g2 or ratio between different string
tensions for N c 2:: 4. 3 ) (3) The dimensionless ratio
T d/ fo of the deconfining temperature Td and string
tension a is expected to be independent of N c witha value J3lrr(D - 2) with D being the space-time
dimensions. 4 )To resolve these issues we numerically investigatedthe order of deconfining phase transition and the ratioof string tensions for Nc = 4. 5 ) We use single-plaquetteaction defined in the fundamental 4- representation of
the SU( 4) gauge group. Combinations of pseudoheatbath or Metropolis and over-relaxation algorithms
are used in updating 4, 6 and 8 x 83 , 123 , 163 or 20 3
lattices. We look at the following observables: plaquette, Polyakov loops, L(x) = (l/Nc)tr Il~::!l U(x, t ; i) ,in 4 (fundamental) , 6 (antisymmetric diquark), 10(symmetric diquark) and 15 (adjoint) representations,deconfinement fraction, and Polyakov loop correlation(L(O)L(f')*) r-v r- 1 exp( -F(r)/T) r-v exp( -Ltar - In r)
in 4 , 6 , 10 and 15 representations.
On a 6 x 20 3 lattice we confirmed coexistence of confined and deconfined phases at temperature (3 = 10.79:
This strongly suggests a first-order deconfining phasetransition. We plan further study with finite-size scaling. String tensions in SU(Nc) pure Yang-Mills system
is classified by its center Z(Nc ) Nc-ality. With N c = 4,
the fundamental (4) charge has 4-ality k = 1, the two
diquark (6 and 10) charges k = 2, and adjoint (15)k = 0. 3 ) Note also that N c = 4 is the first example withdifferent string tensions: in SU(3) pure Yang-Mills system the fundamental (3) and the symmetric diquark(6) tensions are the same.6 ) On a 6 x 163 lattice at(3 = 10.70 and at a weaker coupling of (3 = 10.85 on*1*20.0001
1e-05
1e-06
1e-07
1e-08
1e-09
1e-10

o

2

4

6

8

10

12

Fig. 1. Polyakov loop correlation function in 4 (top), 6(middle) , and 15 (bottom) representations on a 12 3 x 8
lattice at (3 = 10.85.

a smaller lattice of 8 x 123 (see Fig. 1) we find clear
difference between 4- and 6-string tensions extracted
from 4- and 6-Polyakov loop correlations. We also findflattening of the adjoint (15) correlation in the latter.
References
1) R. D. Pisarski and M. Tytgat : Proc. 25th Hirschegg
Workshop on QeD Phase Transition, Hirschegg, Austria, 1997-1 (1997) ; hep-ph/9702340.
2) J. Maldacena: Adv. TheoL Math. Phys . 2 , 231 (1998) ;Int. J. TheoL Phys. 38, 1113 (1999); hep-th/9711200.
3) M. J. Strassler: Proc. Yukawa Int . Seminar 97, p. 439(1997) ; hep-th/9803009.
4) R. D. Pisarski and O. Alvarez: Phys. Rev. D 26 , 3735
(1982).
5) M. Wingate and S. Ohta: to appear Phys. Rev. D, heplat/0006016.
6) S. Ohta, M. Fukugita, and A. Ukawa: Phys. Lett. B
173, 15 (1986).

We acknowledge helpful conversations with M. Creutz, R.
Pisarski , and M. Strassler. We thank RIKEN , BNL and the
US Department of Energy.
Institute for Particle and Nuclear Studies , High Energy Accelerator Research Organization (KEK)
Present address: Physics Department , The Ohio State University, USA

279

RIKEN Accel. Prog. Rep. 34 (2001)

Domain-Wall Fermion Lattice QCD Calculation of Nucleons t
T. Blum, S. Ohta,* l and S. Sasaki*2
The RIKEN-BNL-Columbia-KEK QCD Collaboration have been pursuing the domain-wall fermion(DWF) method in lattice quantum chromo dynamics(QCD).l) In DWF an extra fifth dimension is added to
the lattice. By manipulating a "domain-wall" structure in the fermion mass in this fifth dimension, we
control the number of light fermion species, chirality and mass in the other four space-time dimensions.
In particular: (1) fermion near-zero mode effects arewell understood, (2) small chiral symmetry breaking
induced by the finite extra dimension is described by asingle residual mass parameter in low-energy effective
lagrangian, which is very small in the present calculation, and (3) non-perturbative renormalization works
well. 2) Here we report our more recent studies about
the mass spectrum of the nucleon and its excited state
and the nucleon structure.
Our quenched DWF 3 ) calculation for the first time
succeeded in reproducing the large mass splitting between N(939) and N*(1535) (see Fig. 1). Phenomenological models like the non-relativistic quark model andthe MIT bag model have failed here: these models
must have only a couple of hundred Me V mass splitting
arising from orbital excitation of one valence quark.
We also obtain the isovector vector and axial
charges, gv and gA' of the nucleon. 4) These quantities are well known from the neutron (3 decay, gv =GFcos()e and gA/gV = 1.2670(35). Here G F denotes the Fermi constant and Be the Cabibbo angle.
gv = G F cos Be follows from vector current conservation. In contrast the axial current should receive astrong correction from QeD , resulting in the deviation of the ratio gA / gv from unity. In lattice calculations in general the two relevant currents get renormalized by the lattice cutoff. With conventional fermion
schemes this renormalization usually makes the calculations rather difficult, if not intractable, even forsuch simple quantities like gv and gA' An important
advantage here with DWF is that the lattice renormalizations, Zv and Z A' of the currents are identical

*1

*2

280

As part of the RIKEN-BNL-Columbia-KEK Collaboration:
T. Blum, N. Christ , C. Cristian, C. Dawson, G. Fleming, X.
Liao, G . Liu, R. Mawhinney, S. Ohta, A. Soni, P. Vranas,
M. Wingate, L. Wu, and Y. Zhestkov. We thank RIKEN ,BNL and the US Department of Energy
Institute for Particle and Nuclear Studies, High-Energy Accelerator Research Organization (KEK)
Department of Physics, University of Tokyo

1.6
preliminary

1.5 l-(exp.)**' N·N (exp.)1.4 I-

ID

1.3 I1.2 lCJ)
CJ)

<1l

E

c:

1.0 I-<1l

0.9 I-

~

..c

i

ill ~

X

iii

~

X

0.8 f-*

X
X

0.7 ..

Xx

X

0.6 0.5
0.4

Xi

1.1 l-

00

8 1+ (nucleon)
8(
8 2-

"""*
I

I

I

I

I

I

I

0.00

0.02

0.04

0.06

0.08

0.10

0.12

0.14

m: quark mass

Fig. 1. Dependence of calculated N (x) and N* (0 and <»mass on quark mass. They extrapolate linearly to agree
well with experimental values (blasts at zero quarkmass). All in lattice units, a-I ~ 2 GeV.
so that the lattice ratio (gA / gv ) lattice directly yields
the continuum value. The longitudinal and transverse
quark spin contents, D..q/ gv and 8q/ gv , are obtained at
the same time. Preliminary values from linear extrapolations in quark mass to zero are: gA/gV = 0.62(13) ,D..q/gv = 0.36(14) , and 8q/gv = 0.31(12) . The quite
low value of gA/ gv is under further investigation.
References
1) T. Blum et al.: hep-lat/0007038 , to appear in Phys.
Rev. D, and references therein.
2) C. Dawson: hep-lat/00ll036; Proc. Lattice 2000, editedby A. Patel et al.) Nuel. Phys. B Proc. Suppl. 94, 295(2001) .
3) S. Sasaki: Proc. NSTAR 2000; hep-ph/0004252, andreferences therein.
4) T. Blum, S. Ohta, and S. Sasaki: hep-Iat/OOllOll,
Proc. on Lattice 2000, edited by A. Patel et al.

RIKEN Accel. Prog. Rep. 34 (2001)

Numerical Lattice Field Theories Using
RIKEN VPP Super Computer
S. Kim*1 and S. Ohta*2
Lattice numerical calculation is often the only reliable method to extract quantitative knowledge from
non-perturbative quantum field theories such as quantum chromo dynamics (QCD), the fundamental theoryof the strong interaction. We have been very successful
in using RIKEN VPP vector-parallel super computing
facility for this purpose. In particular, our calculation of light hadron mass spectrum with quenched approximation of QCD (in which vacuum polarization ofquarks are neglected) and staggered fermion quarks is
considered the best available. I) With a very fine lattice spacing of 0.055(1) fm (or the inverse squared coupling of f3 = 6.5) and a large volume of (2.59(5) fm)3
(48 3 x 64 lattice), a realistic nucleon to p- meson mass
ratio of 1.23 ± 0.04 (statistical) ± 0.02 (systematic) was
obtained without chiral extrapolation, as our lightest
quark mass was made so light as about 4.5 MeV. The
flavor symmetry breaking which can arise from coarse
lattice spacing is no longer visible either.
Another application in lattice QCD where fine spacing and large volume are important is heavy quarkonium spectrum calculation. Again the problem addresses non-perturbative nature of the strong interaction and has many remarkable characters in production or decay of quarkonium. 2) However, it has beendifficult to place heavy quarkonium system on a lattice because heavy-quark Compton wavelength (about
1.2 fm for charm and 0.25 fm for bottom) has been too
short compared to the available lattice spacing (typically 0.1 fm or larger): such a coarse lattice spacing cannot resolve the structure of heavy quark wave
function . On the other hand, sufficiently fine latticespacing often meant unacceptably small physical lattice volume which cannot accommodate the extent ofquarkonium wave function. Thus lattice calculations
had to rely on either wild extrapolations from lightquark mass region to heavy quark mass region or uncontrolled approximation of expansion in the inverse ofheavy quark mass. 3 ) In order to overcome these problems, we started a quenched QCD calculation of heavy
quarkonium mass on a 48 3 x64lattice at f3 = 6.8. With
these parameters, lattice spacing is about 0.025 fm andphysical volume is about (1.2 fm)3. These should be
sufficient for charmonium and charmed mesons: only

*1
*2

interpolation in quark mass is required, and not extrapolation. Thus far, about 400 Monte Carlo samples of gauge configuration have been collected and theanalysis is in progress.
A few smaller-scale projects are also in progress:
Phase structure of 3D Thirring model in gauge theory formulation. This needs more accurate determination of the nature of phase transition in view of recent
works. 4 ) Thus, we are studying an application of histogram method to investigate the phase transition ofthis lattice model.
Phase structure of zero-temperature QCD withstaggered-fermion quarks. Here full dynamical treatment of vacuum polarization of quarks is essential, as
the phase structure is expected to depend on the number of light quark flavors. 5 )QCD at finite chemical potential. Monte Carlo algorithm for lattice QCD in general relies on the probability distribution interpretation of the Boltzmann kernelof the generating functional path integral,

where 'IjJ denotes quark fields and Aft gluon fields. If
the action functional S['IjJ, {;, Aft] is real, the Boltzmann
factor e- s can be interpreted as a probability distribution over configurations of quarks and gluons andMonte Carlo algorithms are applicable. Unfortunately
this does not hold for conventional lattice QCD system at finite quark chemical potential: the Boltzmann
factor becomes complex. We are pursuing a different
lattice formulation which can circumvent this problem.
References
1) S. Kim and S. Ohta: Phys. Rev . D 61 , 074506 (2000);
hep-lat/9912001.
2) G. T. Bodwin, E. Braaten, and G. P. Lepage: Phys.
Rev. D 51 , 1125 (1995); Phys. Rev. D 55, 5853 (1997).
3) C. Bernard: Proc. Lattice 2000, Nucl. Phys. B (Proc.
Suppl.), 94,159 (2001); hep-lat/0011064, and references
therein.
4) S. Hands and B. Lucini: Phys. Lett. B 461, 263 (1999);
hep-lat/9906008.
5) F. R. Brown et al.: Phys. Rev. D 46, 5655 (1992);
hep-lat/9206001, and references therein.

Sejong University, Korea
Institute for Particle and Nuclear Studies , High-Energy Accelerator Research Organization (KEK)281

RIKEN Accel. Prog. Rep. 34 (2001)

The Spectrum of the QeD Dirac Operator
T. Wettig
The spectrum of the QCD Dirac operator, D =,,/p,(8p, + gAp,), is of great theoretical interest , in particular because of its relation to spontaneous chiralsymmetry breaking. The Banks-Casher formula, ~ ==I(~'ljJ) I = 7r p( 0) IV, relates the chiral condensate to thespectral density of D defined by p(A) = (2: n l5(A-A n )),where the An are the Dirac eigenvalues and the average
is over the gauge fields weighted by the QCD action.
In various regions of the parameter space, the Dirac
spectrum can be computed analytically. 1) To better
understand the results of lattice gauge simulations, weare particularly interested in QCD in a finite volume V.
Figure 1 shows the energy scales that are relevant at
finite V. For energies below the rho mass, QCD can be
described by an effective chiral Lagrangian Leff. However, perturbative calculations break down for smallenergies of order 1IV~, i. e. chiral perturbation theory only works above this scale. For energies below
the so-called Thouless energy, given by Ee rv /;/~VV,
the theory is dominated by the zero-momentum modes
in Leff' i. e. the kinetic terms can be neglected. In
this regime QCD is described by a zero-dimensional
effective theory known as chiral random matrix theory(RMT). While it is possible (but very hard) to compute nonperturbative results from Leff' chiral RMT
provides a much more convenient mathematical tool(the results agree). There is a finite overlap region,
IIV~ < E < E e , in which both chiral RMT and chiral perturbation theory are applicable.
A typical nonperturbative quantity is the microscopic spectral density Ps of the Dirac operator,

Ps(Z) =

J~oo :~ P (;~) .

1

A,m, EV~

nonpert. regime
zero mode domain (RMT)
chiral pert. theory

Fig. 1. Applicability of various effective theories for QeD
in a finite volume.

282o~~~~~~~~~~

o

5

10

15

20

25

z

Fig. 2. Microscopic spectral density of D on the lattice(histogram) and in chiral RMT (dashed line).

10 2
10

0.1
0.01

10- 3
10- 4
10- 5
0.1

103

10 2

10

10 4

m

Fig. 3. Disconnected scalar susceptibility on the lattice, inchiral RMT, and in chiral perturbation theory. (Thechiral RMT curve is hidden by the data for small m.)dise ( )Xlattice m =This quantity describes the distribution of the individual low-lying Dirac eigenvalues. The result of anSU(2) lattice simulation,2) compared with the analytical RMT result, is shown in Fig. 2.
The disconnected scalar susceptibility is defined on
the lattice in terms of the Dirac eigenvalues,o(3=2.0, V= 10 4

1 /

~

1

N \k~1 (iAk + m)(iAl + m))

- ~/ti>'k~m)2.
\k=1

This quantity is of interest since it diverges at the chiral phase transition with a universal critical exponent.
The result of an SU(3) lattice simulation,3) comparedwith the analytical results of chiral RMT and chiralperturbation theory, is shown in Fig. 3. Clearly, there
is an overlap regime in which both theories describe
the data (m plays the role of an energy).
I would like to thank M. Gockeler, H. Hehl, P. E. L.
Rakow, and A. Schafer for fruitful collaborations.
References
1) J. J. M. Verbaarschot and T. Wettig: Annu. Rev. Nucl.
Part. Sci. 50, 343 (2000).
2) M. E. Berbenni et al.: Phys. Rev. Lett. 80 , 1146 (1998).
3) M. E. Berbenni et al.: Nucl. Phys. B Proc. Suppl. 83,
974 (2000).

RIKEN Accel. Prog. Rep. 34 (2001)

Parity and CP Violation in Hot QCD
D. Kharzeev*
One of the most exciting aspects of relativistic heavy
ion physics is the possibility to produce some truly exotic phases of matter. In this report we describe therecent work 1 ,2) on the topological effects near the deconfinement phase transition, and the related possibility to excite P and CP odd metastable vacuum states.
Consider a linear sigma model with a field <P. Thenthe effects of the anomaly enter exclusively through aterm rv det(<p). As in the nonlinear sigma model, when
the chiral symmetry is spontaneously broken, this term
generates a mass for the rl'. However, in the nonlinear
sigma model, at large N, there is only a mass term forthe r/; four point interactions between rl"s are inducedby the anomaly, but are suppressed by higher powersof 1/N 2 .
For U fields which are constant in spacetime, thepotential for U is
V(U) =

if(tr (M(U + ut)) - a(tr InU - 8)2). (1)The pion decay constant i 7r = 93 MeV, while M is
the quark mass matrix. When M = 0, m~, rv a, soa )",~,/N.
Taking M i j = 1-l;8ij , any vacuum expectation value(v.e.v) of U can be assumed to be diagonal, Uij =ei <Pi 8ij . The potential reduces tof'.JV(qii) = f; ( -~Jt: COS(qii) + ~ (~qii _ e) 2) .

ary point a little bit from 27r , 47r, etc. Because a isnonzero, they will become metastable, distinct fromthe usual vacuum. From (3), these states will act likeregions of nonzero e. Parity and CP are both violated
spontaneously in such a region.
What are the signatures of such exotic states? Most
notably, when the anomaly term a becomes small,there is maximal violation of isospin. At zero temperature, the nonet of pseudo-Goldstone bosons - the
7r'S, K's , ry , and ry', are, to a good approximation,
eigenstates of SU(3) flavor. When the anomaly term
becomes small, while the charged pseudo-Goldstonebosons remain approximate eigenstates of flavor, theneutral ones do not. Without the anomaly, the 7r 0
becomes pure UU , the ry pure dd, and the ry' pure ss.
Consequently, these three mesons become light. Thisis especially pronounced for the ry, as it sheds all of its
strangeness, to become purely dd. Thus the ry and ry'
would be produced copiously, and would manifest itself
in at least two ways. First, light ry's and ry"s decay into
two photons, and so produce an excess at low momentum. Secondly, these mesons decay into pions, which
would be seen in Bose-Einstein correlations. Further,through Dalitz decays, the enhanced production of ry's
and ry"s will enhance the yield of low mass dileptons.
There is another way to observe parity violation, by
measuring the following variable globally, on an eventby-event basis:

(4)

(2)
This is minimized for(3)
Note that as L: ¢i arises from tr In U, it is defined modulo 27r.
Now consider the limit of vanishing a: then there automatically other solutions besides ¢ = 0, ¢ = 27r,47r,
etc. These solutions are equivalent to the trivial vacuum, and so there is nothing new. But for small valuesof a, the term linear in a will only move the station-

Physics Department,

here i is the beam axis, and p are the three momenta of
the pions. This and similar observables are currently
under experimental study by the STAR Collaboration
at RHIC .
References
1) D. Kharzeev, R. Pisarski, and M. Tytgat: Phys. Rev .
Lett. 81, 512 (1998).
2) D. Kharzeev and R. Pisarski: Phys. Rev. D 61 , 111901(2000) .

Brookhaven National Laboratory,

USA

283

RIKEN Accel. Prog. Rep. 34 (2001)

Signature Neutrinos from Ultrahigh-Energy Photons
A. Kusenko*
The origin of ultrahigh-energy cosmic rays,l) withenergies beyond the Greisen-Zatsepin-Kuzmin (GZK)
cutoff}) remains an outstanding puzzle. 3 ) Many of the
proposed explanations invoke new sources, such as superheavy relic particles or topological defects, which
can generate photons at both low and high red shifts.
To understand the origin of the ultrahigh-energy cosmic rays (UHECR), it is crucial to distinguish such
sources from more conventional astrophysical ones.
The latter tend to produce more protons than photons.
In addition, the "astrophysical" candidate sources suchas, e.g., active galactic nuclei, have formed at relatively
low red shift. In contrast, topological defects could operate at much higher red shifts.
Sources of ultrahigh-energy photons that were active at red shift z > 3 can be identified by observationof neutrinos produced in interactions of energetic photons with the background photons. 4 ) This may help
understand the origin of UHECR.
At red shift z the cosmic microwave background radiation (CMBR) has temperature TCMB (z) = 2.7(1 +z) K. Because of this, at high red shift the photonphoton interactions can produce pairs of muons andcharged pions, whose decays generate neutrinos. This
is in sharp contrast with the z ;S 1 case, where thephotons do not produce neutrinos as they lose energy
mainly by scattering off the radio background throughelectron-positron pair production and subsequent electromagnetic cascade. The ratio of the CMBR density to that of universal radio background (RB) increases at higher z, and the process 'Y'YCMB ---+ J-l+ J-l- ---+
e+ e- iJp,vp,iJeve can produce neutrinos. The thresholdfor this lowest-energy neutrino-generating interaction
20. Vr;:.
10 eVIS
S > 2mp, = 0.21 G eV, or E-y > E th ()z =--r+.Z'
At z < 1 the main source of energy loss for photons is electromagnetic cascade that involves e+ e- pair
production (PP) on the radio background photons. 3 )The radio background is generated by normal and radio galaxies. Its present density is higher than thatof CMB photons in the same energy range. The radio
background determines the mean interaction length forthe e+e- pair production. At red shift z, however, thecomoving density of CMB photons is the same, while
the comoving density of the radio background is lower.
Let z R be the value of red shift at which the scatteringof high-energy photons off CMBR dominates over theirscattering off RB. Based on the models of RB, we takezR
3. Another source of energy losses in the electromagnetic cascade is the synchrotron radiation by thef'.J

Department of Physics and Astronomy, UCLA, USA

284

electrons in the intergalactic magnetic field (IGMF).
This is an important effect for red shift z < ZM' whereZM
5 corresponds to the time when IGMF is weak,
and the synchrotron losses are not significant.
Let us now consider the propagation of photons at
Z > Zmin = max (z R , Z M ). In particular, we are interested in the neutrino-generating process 'Y'YCMB ---+
J-l+ p,-. Although the cross section for the electron pair
production is higher than that for the muon pair production, neutrinos are nevertheless produced. This isbecause the high-energy photons are continuously regenerated in the electromagnetic cascade. 3 ) The energy
attenuation length Aeff is much greater than the pair
prod uction interaction length A('Y'YCMB ---+ e + e - ) .
Since Aeff » A('Y'YCMB ---+ J-l + J-l- ), in the absenceof dense radio background all photons with E > Ethpair-produce muons and pions before their energy is
reduced by the cascade. Due to the kinematics, oneof the two muons has a much higher energy than theother, in full analogy with the e+e- case. Muons decay
before they can interact with the photon background.
Each energetic muon produces two neutrinos and anelectron. The latter can regenerate a photon via inverse Compton scattering. This process can repeat
until the energy of a regenerated photon decreases below the threshold for muon pair production.
The flux of neutrinos from muon decays depends
on the cosmological evolution of sources. 4 ) Signatureneutrinos can be observed by such future detectors as
HiRes, Pierre Auger, EUSO, OWL, ICE CUBE, andothers.
This work was supported in part by the US Department of Energy grant DE-FG03-91ER40662, Task C,
as well as by a grant from UCLA Council on Research.
f'.J

References
1) M. Takeda et al.: Phys. Rev. Lett. 81 , 1163 (1998);
M. A. Lawrence, R. J. Reid, and A. A. Watson: J.
Phys. G 17, 733 (1991); D. J. Bird et al.: Phys. Rev.
Lett. 71, 3401 (1993); Astrophys. J. 424, 491 (1994); N.
Hayashida et al.: Astrophys. J. 522, 22·5 (1999); astroph/0008102.
2) K. Greisen: Phys. Rev. Lett. 16, 748 (1966); G. T.
Zatsepin, and V. A. Kuzmin: Pisma Zh. Eksp. Teor.
Fiz. 4, 114 (1966).
3) For review, see, e.g., P. L. Biermann: J. Phys. G 23, 1(1997); P. Bhattacharjee and G. Sigl: Phys. Rep. 327,
109 (2000).
4) A.· Kusenko and M. Postma: hep-ph/0007246.

RIKEN Accel. Prog. Rep. 34 (2001)

Light-Front Realization of Chiral Symmetry Breaking
K. Itakura and S. Maedan*
Finding an appropriate method of describing the chiral symmetry breaking is one of the most important
problems in the light-front (LF) formalism. This isbecause while in the usual quantization scheme thechiral symmetry breaking is attributed to a nontrivial vacuum structure, the vacuum in the LF quantization is kinematically forced to be the Fock vacuum andthus has no structure in it. More strictly speaking, thedispersion relationp_ = -=1..
p2 _
+_
m2
_
2p+

tells us that the sign of light-front energy p- and longitudinal momentum p+ are correlated, and thus imposing the semipositivity of the LF energy p- 2:: 0
indicates that p+ is also positive. If the p+ = 0
state with divergent LF energy is removed, then we
have only positive longitudinal momentum, which excludes the mixing of particle states with the vacuum
state having zero momentum. On the one hand, thisproperty is considered to be a great merit of the LF
formalism. Due to the simplicity of the vacuum, we
can describe excited states as valence states, which reminds us of the constituent picture of hadrons. On theother hand, the constituent picture is considered to berealized by the dynamical chiral symmetry breaking.
As mentioned above, this phenomenon is, in the usual
formulation, described by determining a new vacuum
which breaks the chiral symmetry but is energeticallyfavored. Therefore a question comes to mind: How
can the chiral symmetry breaking be realized in the
LF quantization which has a trivial vacuum?
In recent years, we have been studying this problem
using the chiral Yukawa model and the N ambu-JonaLasinio model. Details can be found in Ref. 1 and alsoa review of our approach is given in Ref. 2. Based on
careful analyses of the models, we found clear answers
to the following three fundamental questions:(1) How is the LF chiral transformation different fromthe ordinary chiral transformation? This should
be asked because the LF chiral transformation isdefined only on the "good" spinor component 'I/J+(independent degrees of freedom):'I/J+ ----+ eh5 () 'I/J+,
where 'I/J = 'I/J+ + 'I/J-, 'I/J± = 2- 1 / 2 "'j0"'j±'I/J.
(2) How does a gap equation for the chiral condensate
Finding a gap equation, a nonlinear
emerge?
equation for an order parameter, is a standard andimportant step to reach the symmetry breaking.

(3) What is the consequence of the coexistence ofnonzero chiral condensate (7j;'I/J) =I 0 and the trivial
Fock vacuum?

In the LF formalism, the longitudinal zero mode ofa scalar field and half of the spinor component (the"bad" component 'I/J-) are not independent degrees of
freedom. Therefore, we have constraint equations (thezero-mode and fermionic constraints) which make theanalysis extraordinarily difficult.
Answers to Question 1) were achieved after wesolved the constraints classically. We have verified that
the LF chiral transformation is eventually equivalent tothe usual chiral transformation in the massless fermion
case.
The answer to Question 2) is based on our recognition that the nonlinear constraints themselves are
the keys to the gap equation. Indeed, we found thatthe constraints become the gap equation if we treat
them nonperturbatively in a quantum theory. We also
noted that it was very important to carefully treat the
infrared divergences in p+ integrals when we identified
the constraints with the gap equations. By solving the
gap equation, we obtained a nonzero chiral condensate.
Question 3) is intimately related to another important problem: reconciliation between the invarianceof the vacuum under the LF chiral transformation
Q~F 10) = 0 and the nonzero chiral condensate. Bothare understood by the modified chiral transformation
laws for the dependent variables:

where both fermion bilinear operators contain the badcomponent and thus have different forms depending on
the solutions of the constraints (gap equations). The
unusual transformation law of the bad component also
indicates a surprising result

Eventually, the characteristic features of the LF chiralsymmetry in the broken phase are found to be that thechiral charge Q5 is no longer conserved and that thetransformation for the scalar and pseudoscalar fields
is modified. We have also succeeded in computing
the light-cone wave functions of the scalar and pseudoscalar mesons in the N ambu-J ona-Lasinio model.
References
1) K. Itakura and S. Maedan: Phys. Rev. D 61, 045009(2000); Phys. Rev. D 62, 105016 (2000).
2) K. Itakura and S. Maedan: hep-ph/0102330.

Department of Physics, Tokyo National College of Technology

285

RIKEN Accel. Prog. Rep. 34 (2001)

Transport Model for Relativistic Nuclear Collisions
Y. Nara, S. E. Vance,*1 and P. Csizmadia*2
Data from the first run at the Relativistic Heavy
Ion Collider (RHIC) at Brookhaven National Laboratory have shown a large elliptic flow 1) and a moderate
number of charge particles. 2) Collisions at RHIC energies are different from those in previous experiments atlower energies since many minijets (semi-hard partons)
are produced in the initial condition.
Many microscopic models of heavy-ion interactions
such as 3- 6) do not include parton degrees of freedom
and only include soft hadronic resonance and Regge
physics which are crucial in understanding interactions
at AGS and SPS energies. On the other hand, the
HIJING modeI 7 ,8) focuses only on the minijet initialcondition and at present does not include either parton or hadron rescattering. Thus, new models that include both partonic and hadronic physics are needed.
One attempt at the development of such a model canbe found in Ref. 9. In this report, a new transportmodel is presented through which the importance ofthe rescattering of the initially produced partons at
RHIC energies can be studied.
This model contains the following elements. First,
minijets produced in AA collisions are calculated assuming Eikonal approximation for pQCD (HIJING) as
an initial condition of parton transport. Using thisinitial condition, we evolve the initially produced partons using the relativistic Boltzmann equation in which
the parton-parton cross sections are calculated from
pQCD. The processes g + g --+ g + g , g + g ~ q + ii,
g + q --+ g + q and g + ii --+ g + ii, along with radiation associated with the outgoing partons (final stateradiation) are included. This calculation is a full 3-D
simulation where assumptions such as boost invarianceare not made. Once the partons finish rescattering, theminijets are fragmented into hadrons. Future additions
to this model must be to include the rescattering of the
produced hadrons.
The effect of these interactions is to increase u and dquarks jets by 80%, s quark jets by 50%, and c quark
jets by 20%. In addition, these newly produced jets
are shown to have smaller mean PT. Figure 1 shows
the gluon transverse momentum distributions from ourcalculations at vis = 130 A GeV for central Au+Au
collisions (b < 3 fm). The result of the rescattering including the final-state radiation of the gluon jets is aloss of energy of minijets at high PT and a slight increase in the low 1 Ge V < PT < 2 Ge V region. The
transverse energy (dET/dy) at mid-rapidity decreases
due to the parton-parton collisions. g) The effect of the
*1

*2

286

Physics Department , Brookhaven National Laboratory,USA
KFKI Research Institute for Particle and Nuclear Physics(RMKI) , Hungary-------- lOltla a uoo.s .
1- radiation-- 2 ~

Au + Au, b<3fm
s 1/2=130AGeV

10
NI-

C.1

~
"

10-1
-2

10

10-3

2

3

456
PT (GeV)

7

8

9

10

Fig. 1. Minijet gluon transverse momentum distributions
for Au+Au collisions (b < 3 fm) at y's = 130 A GeV.
The dotted line denotes the gluon distribution from theinitial conditions and the solid line represents gluon distribution after rescattering.

final state radiation among minijet interactions are
small in our model. In comparison, other models of
jet energy loss, such as the HIJING jet quenching calculation, increase hadron yields. In this work, softmode of the plasma is treated by string and we do notinclude interaction of strings. Instead of strings , soft
gluons can be included. Then we can follow the time
evolution of the soft mode.
Other possible signatures of this scattering phase are
the K+ /7r+ yields as a function of PT and the acoplanarity of the D and Jj meson pair. Work is in progress
to extract those observables.
References
1) STAR Collaboration: Phys. Rev. Lett. 86 , 402 (2000).
2) PHOBOS Collaboration: Phys. Rev. Lett. 85, 3100
(2000) .
3) B. Andersson et al.: Z. Phys. C 57, 485 (1993).
4) H. Sorge: Phys. Rev. C 52, 3291 (1995).
5) K. Werner: Phys. Rep. 87, 232 (1993).
6) S. A. Bass et al.: Prog. Part. Nucl. Phys. 41 , 225 (1998).
7) X. N. Wang and M. Gyulassy: Phys. Rev. D 44, 3501
(1991) .
8) M. Gyulassy and X. N. Wang: Compo Phys. Comm. 83,
307 (1994).
9) B. Zhang, C. M. Ko , B. -A. Li, and Z. Lin: Phys. Rev.
C 61 , 067901 (2000).

RI KEN Accel. Prog. Rep. 34 (2001)

Properties of Gluons in Color Superconductors
D. H. Rischke
Cold, dense quark matter is a color superconductor.l) Thanks to asymptotic freedom, one can compute quantities of this phase at large quark chemical potentials, j.l, in a controlled way. For instance,
the magnitude of the color-superconducting gap parameter, ¢, can be self-consistently computed froma Dyson-Schwinger equation in one-loop approximation. 2 ) Commonly, one uses the "hard, dense loop
(HDL) approximation" 3) for the gluon propagator in
the loop. In cold, dense quark matter, quark particlehole excitations constitute the dominant contribution
to the gluon self-energy. In the HDL approximation,
however, the quarks are assumed to be those in a normal conductor, not of a superconductor. This is inprinciple incorrect, and the correct solution could leadto changes in the magnitude of ¢.
In order to test this hypothesis, one has to computethe quark loop in the gluon self-energy with quark
propagators appropriate for a color-superconducting
medium, res urn the resulting expression to obtain thegluon propagator, and finally use this modified propagator when solving the gap equation.
This is an ambitious program which has not been
completed up to date. I report here on a first step inthis direction, namely the computation of the gluon
self-energy in the limit of vanishing gluon energy andTable 1. Results for the Debye and Meissner masses in
two- and three- flavor color superconductors, mg ==JNj/6gJ-L/7r.

I flavor II gluon color

I
I

2
2
2

3

II
II

1-3
4-7
8
1-8

-II~~(O)
0

!m!

3m.
21

A In2 m2JS!ln~n(O)
0t:l

2I-~ln2 m~

momentum. 4 ) In this limit, the self-energy of electricgluons determines the Debye mass, and that of magnetic gluons the Meissner mass. The results for the
Debye and Meissner masses in color superconductors
with Nf = 2 and Nf = 3 flavors of massless quarks
are summarized in Table 1. Calculations of the gluon
self-energy for Nf = 2 and Nf = 3 at non-vanishingenergy and momentum are presently under way.
References
1) D . Bailin and A. Love: Phys. Rep. 107, 325 (1984).
2) For instance, R. D. Pisarski and D. H. Rischke: Phys.
Rev. D 61, 051501, 074017 (2000).
3) M. Le Bellac: Thermal Field Theory, (Cambridge University Press, Cambridge, 1996).
4) D. H. Rischke: Phys. Rev. D 62, 034007, 054017 (2000).

287

RIKEN Accel. Prog. Rep. 34 (2001)

Phases of QeD at High Baryon Density
T. Schafer
We have studied the phase structure of QCD at very
high baryon density p » A"Qb D' In this regime thenatural degrees of freedom are quasi particles and holes
in the vicinity of the Fermi surface. Since the Fermi
momentum is large, asymptotic freedom implies thatthe interaction between quasiparticles is weak. We
know from the theory of superconductivity that the
Fermi surface is unstable in the presence of even an
arbitrarily weak attractive interaction. At very large
density, the attraction is provided by one-gluon exchange between quarks in a color anti-symmetric :3
state. QCD at high density is therefore expected tobehave as a color superconductor. 1 ,2)Color superconductivity implies that the local gauge
symmetry is broken by a Higgs mechanism. There isa gap in the fermion excitation spectrum and gauge
fields are screened by the Meissner effect. In addition
to that, color superconductivity can lead to the breakdown of global symmetries. In particular, for Nf > 2,chiral symmetry is broken even at asymptotically large
baryon density.
If the density is large, the gap can be calculated in
weak coupling perturbation theory. The gap equation
is dominated by magnetic gluon exchange and we find 3 )

(1)

288

In this regime, we can also study the phasestructure. 3 ) The super conducting order parameter depends sensitively on the number of flavors and theirmasses. For two degenerate flavors the superconducting phase breaks color SU(3) --+ SU(2) but leaves chiral symmetry unbroken. 2 ) In the case of three degenerate flavors the color SU(3) and chiral SU(3) x SU(3)symmetry are broken, but a diagonal SU(3)v symmetry survives. If the strange quark mass is included ,one finds a first order phase transition between this twophases. For Nf > 3 chiral symmetry is broken, but thechiral symmetry breaking pattern is different from theone at zero density. For Nf = 1, one finds a spin 1 superconductor where the color and rotational symmetry
are broken according to SU(3) x SO(3) --+ 80(3).
References
1) D. Bailin and A. Love: Phys. Rep. 107, 325 (1984).
2) R . Rapp, T. Schafer, E. V. Shuryak, and M. Velkovsky:
Phys. Rev . Lett. 81 , 53 (1998); M. Alford , K.
Rajagopal, and F. Wilczek: Phys. Lett. B 4 22 , 247(1998).
3) T. Schafer: nucl-th/0010049 , and references therein.

RIKEN Accel. Prog. Rep. 34 (2001)

Signals of Hypermatter at RHIC
J. Schaffner-Bielich, R. Mattiello, *1 and H. Sorge*2
We investigated the production and decay of possible bound states of one hyperon with a nucleon andof two hyperons at the Relativistic Heavy Ion Collider(RHIC) at Brookhaven National Laboratory.1) Up to
200 hyperons may be produced in a single central collision of two gold nuclei at RHIC. This opens up the
possibility of forming and detecting new states of matter with hyperons. The production rates for forming dibaryon states with hyperons has been estimatedusing the wave function coalescence model. The initial phase space distribution of the single baryons was
taken from the event generator RQMDv2.4. The wave
function of the dibaryon states was approximated by a
Hulthen wave function. We obtained production estimates in the range of 10- 2 to 10- 4 per central collision.
The rapidity distribution is fiat, enabling detection at
forward and backward rapidity and at mid-rapidity.
The production numbers will be enhanced if a chirally
restored phase or a quark-gluon plasma is formed in
the collision. In the former case, the baryon masses
drop and thus more baryons are produced. In the latter case, the number of strange quarks will increasein the plasma, generating more strange hadrons in the
final state.
The strange dibaryons, if formed and bound, can bedetected by their weak decay. We calculated the lifetime as well as the branching ratios of various strange
dibaryon candidates. We use SU(3) symmetry to describe the weak nonleptonic decay of hyperons. The
weak operator is assumed to be proportional to theGell-Mann matrix >'6 which ensures hypercharge violation I~YI = 1, the ~I = 1/2 rule and the LeeSugawara relation for the parity-violating amplitudes.
The parity-violating as well as the parity-conserving
amplitudes can be described effectively by the Lagrangian:.[ = DTrBB [P, >'6] + FTrB [P, >'6] B+ GTrBP'Y5B>'6 + HTrB>'6'Y5 BP+ JTrB{P, >'6}'Y5B.
Here, B stands for the baryons and P for the pseudoscalar mesons. The five parameters D to J are fitted
to the measured 14 amplitudes and the fit results in areasonable description of all measured amplitudes. We
note that the standard model for the weak nonleptonic
decay of hyperons, the pole model, fails to explain theparity-conserving amplitudes. 2) The nonmesonic decay
modes of the strange dibaryons are modeled by the exchange of pions and kaons using the above interaction
for the weak vertex and SU(6) symmetry for the strong*1*2

vertex. The wave function of the dibaryons is again assumed to be of Hulthen-like shape with varying binding
energy.
The calculated lifetimes of the strange dibaryons are
somewhat shorter than the ones for hyperons in freespace, i. e. the decay lengths are about CT = 1- 5 cm.
The lifetime decreases with binding energy as the twobaryons are closer together in phase-space. We alsofind that the branching ratios depend sensitively on thebinding energy. The mesonic decay dominates at smallbinding energies of approximately 1- 3 MeV, while thenonmesonic decay is most pronounced for larger binding energies. This is to be expected as this behaviour
has been observed experimentally for the weak mesonicand nonmesonic decay of hypernuclei. In particular,
the nonmesonic decay is of interest for heavy-ion experiments, as it involves only two hadrons in the final state. For a possible bound dilambda state, wefind that the main decay channel is AA ---+ ~- +p, thesame as for the hypothetical H-dibaryon. 3 ) The 3 0 p
dibaryon decays mainly to a A and a proton, while theA3° dibaryon can be seen by its decay to a 3- and a
proton. Doubly negatively charged dibaryons, like the~-3-, can decay to two ~- 's, a unique decay prong.
Strange dibaryons, bound or not , can be detected by
the following means:(1) Experiments with a time-projection chamber can
track for unique exotic decays like a charged particle
decaying to two charged particles or tracks forming avertex a few cm outside the target.
(2) Experiments sensitive to hyperons can look forpeaks in the invariant mass spectrum of pp, pA, AA,
p3-, and A3- by background subtraction using event
mixing. This method is sensitive to both bound states
as well as unbound states close to the threshold witha small decay width.
(3) The strong interaction force of AA and A3- andpossible resonance structures can be probed in correlation functions as they depend sensitively on final-stateinteractions. Note that the Coulomb potential does
not mask the strong interactions so that information
about the presently unknown hyperon-hyperon forces
can be extracted directly.4)
References
1) J. Schaffner-Bielich, R. Mattiello, and H. Sorge: Phys.
Rev. Lett. 84, 4305 (2000).
2) J. F. Donoghue, E. Golowich, and B. R. Holstein: Phys.
Rep. 131, 319 (1986).
3) R. L. Jaffe: Phys. Rev. Lett. 38, 195 (1977).
4) A. Ohnishi, Y. Hirata, Y. Nara, S. Shinmura, and Y.
Akaishi: Nucl. Phys. A 670, 297 (2000).

Niels Bohr Institute, Denmark
State University of New York, USA

289

RIKEN Accel. Prog. Rep. 34 (2001)

Bottom-Up Thermalization In Heavy-Ion Collisions
R. Baier,*l A. H. Mueller ,*2 D . Schiff,*3 and D. T. Son*2
It is possible that at RHIC, for the first time , heavyion collisions occur at energies high enough to be described by perturbative QCD. At the Large Hadron
Collider (LHC) , perturbative QCD is expected to work
even better. The relevant hard scale is the saturation
scale Qs, estimated to be 1 GeV at RHIC and 2- 3 GeV
at LHC. 1- 5)
The single most important issue in the physics ofheavy-ion collisions is thermalization. The conventional argument in favor of thermalization is that atlarger collision energies , more gluons are freed in thefirst moment after the collision, and these gluons collide more frequently with each other. However, thedistribution of these gluons is initially very far fromthermal equilibrium. In addition, the strong coupling
constant decreases at high energies, making thermalization harder to achieve. Whether the system hasenough time to equilibrate before falling apart is thus
a delicate issue requiring detailed consideration of different physical processes.
In a recent paper,6) we show that in the limit
Q s » AQCD corresponding to very large nuclei and/ora very high collision energy, thermalization occurs relatively fast while the system is still undergoing onedimensional expansion. The unexpected feature of ouranalysis is the manner in which thermalization occurs.
During the first period, the most important process isthe emission of soft gluons. At first , these soft gluons are too few to have any influence on the evolution of the whole system, but at approximately time
7 rv 0'. - 3/ 2Q-;1 , where 0'. is the strong coupling constant at the scale Qs, soft gluons begin to dominate theDebye screening even while their density is still muchsmaller than that of the hard ones. The number of soft
gluons becomes comparable to that of the hard ones
at time 7 rv 0'. - 5/ 2Q-;1 , after which most gluons aresoft. The soft gluons then collide very frequently witheach other and achieve thermal equilibration amongst
themselves. At first , the temperature of the thermalbath formed by soft gluons is 0'.1 / 2Qs, and soft gluons
carry only a fraction 0'.1/2 of the total energy. The
system as a whole is still not in thermal equilibrium,
since most of the energy is carried by a small numberof hard gluons . These few gluons collide with the soft
gluons of the thermal bath and constantly lose energy
to the latter, heating up the soft thermal bath. During this time, the temperature of the soft thermal bathgrows linearly with time, T rv 0'.3Q;7. Full thermal-

*1
*2
*3

290

Universibit Bielefeld , Germany
Columbia University, USA
Universite Paris-Sud, France

ization is achieved when the primary hard gluons havelost all their energy. Parametrically, this happens at
7 rv 0'.-13/ 5Q-;1 , at which time the temperature of thesystem achieves the maximal value of 0'.2/ 5Qs.
We have derived the kinetic equations that describe
the evolution of the system during the last period
Q s7 »0'.-5/ 2. At these times, the system is characterized by the temperature of the soft sector T and
the energy spectrum of the hard gluons E(p) , which
evolve with time according to the following equations~! (H(p)) "~! j dx h(x) [x! E(~) - ~E(P) l,
=

o
7

:/3

aa7 (7 4/ 3gET4) = bho0'.2N~ p-olimp~E(p) ,where gE = 7[2(N; -1)/15, N = ~(N; -1)T3, h(x) =h o(1 - x + x 2)5/2(X - x 2)-3/2 , b ~ 4.96 , and

N;

_ 2
1/2
5
2
ho - 7[1/2 (N; _ 1)1/2 In [0'. (Q s 7) ].

Surprisingly, the time dependence of the temperatureof the soft sector in the (admittedly narrow) region
0'.-5/ 2 « Qs7 « 0'.-13/5 can be found almost analytically, and the result depends only on the total numberof primary hard gluons (but not on their distributionfunction).
Although the analysis requires a small coupling, one
can hope that many qualitative features of this picture
are already present in heavy-ion collisions at LHC oreven at RHIC energies. At the very least , the finding
gives us confidence that thermalization always occurs
in heavy-ion collisions at sufficiently high energies.
References
1) L. V. Gribov, E . M. Levin, and M. G. Ryskin: Phys.
Rep. 100, 1 (1983).
2) J.-P. Blaizot and A. H. Mueller: Nucl. Phys. B 289 , 847(1987).
3) L. McLerran and R. Venugopalan: Phys. Rev. D 49 ,
2233 (1994); Phys. Rev. D 49, 3352 (1994); Phys. Rev.
D 50 , 2225 (1994).
4) J. Jalilian-Marian, A. Kovner, L. McLerran, and H.
Weigert: Phys. Rev. D 5 5 , 5414 (1997).
5) K . J . Eskola, K . Kajantie, P. V . Ruuskanen, and K.
Thominen: Nucl. Phys. B 570 , 379 (2000).
6) R . Baier, A. H. Mueller, D. Schiff, and D. T . Son: Phys.
Lett. B, in press; hep-ph/0009237.

RIKEN Accel. Prog. Rep. 34 (2001)

Isospin Dense Matter and Quark-Hadron Continuity
M. A. Stephanov*l and D. T. Son*2
Good knowledge of QCD in the regime of finite temperature and baryon density is crucial for understanding a wide range of phenomena, from heavy-ion collisions to neutron stars and cosmology. To understandthe regime of finite baryon density, one should be able
to follow the transition from hadronic to quark degrees
of freedom by increasing the density of a conserved
charge (such as baryon number) , i. e., without invoking the temperature. This is the motivation for us toturn to QCD at finite chemical potential J.LI of isospin(more precisely, of the third component, h). Natureprovides us with nonzero J.L! systems in the form ofisospin-asymmetric matter. However, such matter contains both isospin density and baryon number density.
In contra..')t , the idealized system considered in this report does not carry baryon number: the chemical potentials of the two light quarks, u and d, are equal inmagnitude, IJ.LII/2 , and opposite in sign.
Small isospin densities- When J.LI is small comparedto the chiral scale (mp) , we can use chiral perturbation
theory. For zero quark mass and zero J.LI , the pions
are massless Goldstone bosons of spontaneously broken
SU(2) L x SU(2) R chiral symmetry. The Lagrangian
describing the pion fields to lowest order in J.LI, m andderivatives has the form:
2f2
f2.c eff = 2.TrV'~V'~t_mn n ReTr~
(1)
4
v
v
2
'

start from a theory with three pions, there are two
massive modes which can be identified with 7[0 and alinear combination of 7[+ and 7[-. At the condensationthreshold , mno = mn and the mass of the other mode
is 2m n , while for IJ.LII » m n , both masses approach
IJ.LII·The isospin density is determined by differentiating
the ground state energy with respect to J.LI and is equalto:where the covariant derivative is defined as(5)
Due to the Cooper pairing, the fermion spectrum acquires a gap ~ at the Fermi surface, where(2)
Using Eq. (1) one can straightforwardly determine
the vacuum alignment of ~ as a function of J.LI and thespectrum of excitations around the vacuum.
(i) For lJ.Lrl < m n , the system is in the same groundstate as when J.LI = 0: ~ = 1. This is because thelowest-lying pion state costs a positive energy mn -IJ.L! I
to excite, which is impossible at zero temperature.
(ii) When 1/111exceeds mn it is favorable to excite
7[- quanta, which form a Bose condensate. In the language of the effective theory, such a pion condensate is
described by a tilt of the chiral condensate ~,~ = cos a + i( T1 cos ¢ + T2 sin ¢) sin a;

cos a = m;/ J.LJ.

(3)

The tilt angle a is determined by minimizing the vacuum energy. The energy is degenerate with respect tothe angle ¢, corresponding to the spontaneous breaking of the U(l)L+R symmetry generated by h in the
Lagrangian (1). The ground state is a pion superfluid, with one massless Goldstone mode. Since we*1*2

University of Illinois at Chicago, USA
Columbia University, USA

m!)

2 sm
. 2 a = fnJ.LI
2 ( 1 - J.LY
nI = fnJ.LI.

(4)

Asymptotically high isospin densities- In the opposite limit of very large isospin densities, or IJ.LI I » m p ,the description in terms of quark degrees of freedom
applies since these degrees of freedom are weakly interacting due to asymptotic freedom. In our case oflarge negative J.LI , or nI , the ground state consists ofd quarks and u antiquarks which, neglecting the interaction, fill two Fermi spheres with equal radii IJ.LII/2.
Turning on the interaction between the fermions leads
to instability with respect to the formation and condensation of Cooper pairs, similar, to an extent, to thediquark pairing at high baryon density. In our case,
J.LI < 0, the Cooper pair consists of a u and a d inthe color singlet channel. The order parameter has
the same quantum numbers as the pion condensate atlower densities ,~ = blJ.LIlg - 5 e- c / g ,c = 37[2/2,(6)and g should be evaluated at the scale IJ.LII.
Quark-hadron continuity- Since the order parameter (5) has the same quantum numbers and breaks thesame symmetry as the pion condensate in the lowdensity regime, it is plausible that there is no phasetransition along the J.LI axis. In this case, the Bose
condensate of weakly interacting pions smoothly transforms into the superfluid state of ud Cooper pairs. The
situation is very similar to that of strongly coupled
superconductors with a "pseudogap," and possibly ofhigh-temperature superconductors. This also parallels the continuity between nuclear and quark matter in three-flavor QCD as conjectured by Schafer andWilczek. We hence conjecture that in two-flavor QCD
one can move continuously from the hadron phase to
the quark phase without encountering a phase transition. Since a first-order deconfinement phase transition at intermediate isospin chemical potential cannot
be rigorously ruled out (though it is unlikely) , this conjecture needs to be verified by lattice calculations.

291

RIKEN Accel. Prog. Rep. 34 (2001 )An Effective Theory of Nuclear MatterU. van Kolck*
The description of relativistic heavy-ion collisions requires an understanding of the hadronic phase of the
QCD phase diagram. We have been developing a systematic framework to predict matter at finite baryonicdensity p and temperature T based on QCD , throughthe use of effective field theory (EFT) methods. The
most general Lagrangian involving low-energy degrees
of freedom and consistent with the symmetries of QCD
is constructed. Interactions are ordered according to
an expansion in powers of momenta (related to p andT). To any given order, observables are written interms of a finite number of parameters, which in principle can be calculated from details of the QCD dynamics (for example, through lattice methods). As in
the case of a pion gas,1) the breakdown of the expansion in T at finite p should signal the position of thetransition.
Two EFTs are being considered. At lowest energies,
nucleons have only contact interactions. At higher energies , pions (but not heavier mesons) are accounted
for explicitly as well, and chiral symmetry plays an essential role in guaranteeing that the nuclear potential
has an expansion in momenta.
The two-nucleon system has been investigated 2 ) including some issues of renormalization stemming

University of Arizona, USA

292

from the singular nature of the potentiaI 3 )- and thethree-nucleon system solved 4 ) in leading order. We
are currently working on the four-nucleon system inorder to complete the determination of the leading fewnucleon forces. Due to the Pauli principle, interactions
with more than four nucleons should involve derivatives and thus be suppressed.
At the same time, the first steps are being taken
in developing the tools for calculating nuclear matter
properties. Using Monte Carlo methods in a spatial
lattice, we have solved 5 ) exactly the toy problem of
nucleons interacting via two-body contact forces withfree coefficients, at finite T. Generalization to EFT
interactions is in progress.
References
1) P . Gerber and H. Leutwyler: Nuel. Phys. B 321, 387(1989).
2) U. van Kolek: Prog. Part. Nucl. Phys. 43, 337 (1999).
3) S. R. Beane, P. F. Bedaque, L. Childress, A. Kryjevski ,J. McGuire, and U. van Kolek: quant-ph/0010073.
4) P. F. Bedaque, H . W. Hammer, and U. van Kolek: Nuel.
Phys. A 676, 357 (2000).
5) H. M. Miiller, S. E. Koonin , R. Seki, and U. van Kolek:
Phys. Rev. C 61 , 044320 (2000).

RIKEN Accel. Prog. Rep. 34 (2001)

Looking for a Colored Glass Condensate in High Energy Collisions
R. Venugopalan*
We have learnt from HERA that the gluon density
in a proton grows very rapidly at small values of X Bj'
At sufficiently small values of XBj, if the density ofgluons in a proton is so large that they begin to overlap, the many body repulsive and attractive interactions among the gluons conspire to form a novel stateof matter we will call a Colored Glass Condensate l )(CGC). The reason for this terminology is as follows.
The matter is colored since gluons carry color charge;
it is a glass because there is a formal analogy between
the infrared properties of this theory and that of a spinglass; it is a condensate because most of the gluons areconcentrated in a narrow band of momentum states ofhigh occupation number.
The properties of the colored glass condensate aredescribed by a classical effective field theory (EFT)of QCD. 2 ) The EFT is characterized by a bulk scale
Q;- the gluon density per unit area of modes with x's
greater than the x value of interest. Since it is the
only scale in the EFT, if Q 8 » AQC D , the physics
of the CGC can be studied using weak coupling techniques. It has been shown recently3) that Wilsonian
renormalization group techniques can be applied to
the EFT- the scale Q8 grows with decreasing XBj ' In
the limit of low parton densities, the standard QCD
evolution equations, known by the acronyms DGLAP
and BFKL, are recovered. 4 ) The regime of high partondensities is described by a non-linear renormalizationgroup equation. In the large Nc limit, it agrees withan equation derived by Balitsky and Kovchegov independently using different techniques. 5 )Since the current and future generation of collider
experiments will begin probing large parton densities,
it will be interesting to look for signatures of the CGC.
In the context of heavy ion collisions, A. Krasnitz andI have shown that the initial energy and number distribution of produced gluons is directly and simply related to the scale Q 8 of the condensate. 6 ) Further, J.
Bjoraker and I have shown that the equilibration time
and the initial temperature of the quark gluon plasma
can be related to the scale Q8 . 7 ) This was also shown
independently by Baier, Mueller, Schiff and Son, who
also included 2 -? 3 processes that were not included
in our approach. 8 ) Work is underway to see if RHIC
data can be understood in this framework.

Signatures of the CGC can also be observed in pA
and eA collisions. We will focus here on eA collisions. 9 )In a high energy eA collider (the proposed eRHIC
at BNL) the properties of the CGC can be studied
through a variety of inclusive and semi-inclusive measurements. For instance, one expects a striking deviation in dF2/dln(Q2) (F2 is the electromagnetic form
factor of a nucleus) versus Q2 for a fixed x - from the
QCD-DGLAP predictions. A maximum is also predicted in the ratio FL/ FT. Note that the longitudinal
structure function FL will be measured at eRHIC for
the first time. Semi-inclusive measurements will provide striking measures of the CGC. For instance, one
expects hard diffractive events - those events witha hard final state (Mx » AQC D) and a large rapidity gap - to be about 30% of the cross-section!
Also, diffractive versus inclusive vector meson production should be very different depending on whether thesize of the meson Rv is larger or smaller than 1/Q8'
If Rv > 1/Q8' (as for the p, the w, and the ¢) thenone expects (}~ffractive = 0.5(}i~clusive · For Rv < 1/Q8'() ~ffractive « () ~clusive (as is the case for the Y).
References
1) L. McLerran: BNL-Rep. 52606, 59 (2000), see Ref. 9.
2) L. McLerran and R. Venugopalan: Phys. Rev. D 49,
2233 (1994); Phys. Rev. D 49, 3352 (1994); Phys. Rev.
D 50, 2225 (1994).
3) J. Jalilian-Marian, A. Kovner, L. McLerran, and H.
Weigert: Phys. Rev. D 55, 5414 (1997) .
4) J. Jalilian-Marian, A. Kovner, A. Leonidov, and H.
Weigert: Nucl. Phys. B 504, 415 (1997); Phys. Rev.
D 59 , 014015 (1999).
5) Y. V. Kovchegov: Phys. Rev. D 60, 034008 (1999);
1. Balitsky: Nucl. Phys. B 463, 99 (1996); E. Iancu,
A. Leonidov, and L. McLerran: SACLAY-TOO-166;
BNL-NT-00-24, Los Alamos e-Print Archive; hep-ph/001124l.
6) A. Krasnitz and R. Venugopalan: Phys. Rev. Lett. 84,4309 (2000); hep-ph/0007108.
7) J. Bjoraker and R. Venugopalan: Phys. Rev. C 63,
024609 (2001).
8) R. Baier, A. H. Mueller, D. Schiff, and D. Son: hep-ph/0009237.
9) Proc. of the eRHIC Summer Meet., BNL Formal Rep.
BNL-52606, (2000).

Brookhaven National Laboratory, USA

293

RIKEN Accel. Prog. Rep. 34 (2001)

Leading Local Operator Analysis of .pI ---+ .p1T"1T" Processes
H. Fujii
Quarkonium (<p) is a QeD bound state of a heavy
quark Q and a heavy antiquark Q, such as J/'I/J and
Y. Due to the heavy mass of its constituents, its size
is very small as compared with the typical QeD scale
AQ~D rv 1 fm. Quarkonium is, therefore, thought to bea clean theoretical laboratory to carry out the perturbative treatment (asymptotic freedom). However, thenonperturbative aspects must be taken into accountproperlyl) when studying the interaction of quarkonium with other light hadrons , which is essential for
drawing a conclusion from the anomalous suppressionof J /'I/J observed in heavy-ion experiments.
Here we calculate the decay rate of <P' -4 <P7r7r basedon the factorization ansatz at the scale of the quarkonium size. The coupling between <p (/) and soft gluons
is described by the perturbation theory, which leads tothe multipole expansion of the color fields. Then the
hadronization amplitude of the soft gluons to the light
hadrons is estimated using the low-energy theorem.
In the leading order of the multi pole expansion, theamplitude for <P' -4 <P7r7r is written as
M ab= g2 (¢7r a 7r b lriEiA
61.

H8 + E' + 'lDor j EjAI¢/),

where g is the strong coupling constant, EA the color
electric fields and r the relative coordinate between Q
and Q. This expression simply indicates that the initial quarkonium (internal) state changes into the octet
state via the color E1 transition, propagates with the
Hamiltonian H8 with energy -E ' - iD o, and returns tothe singlet state again via the color E1 transition.
Although crude, we approximate this amplitude bya factorized form:
2

M ab rv2

L ao d \7r a 7r b IE iA EiA IO) ,2 EO

where 8ij (a6/ Eo)d:::: ~ Jot:. d~ (¢lri(H8+ E' +Q) - Irjl¢/)is calculable using the quarkonium wave function, andb. = mq,' - mq,.
The remaining part of the pion matrix element contains the physics of the long-distance part. We evaluate this part using the low-energy theorem for the
QeD stress tensor: 2 )Mob ~ (:~d) (4;2) sF(s)oob,

where s = (PI + P2)2, and the form factor (Omnes
function) F( s) obtained from the 7r7r phase shift data
is included here in order to take the pion final stateinteractions into account.
In numerical calculation, we take the Coulomb wave
function for the quarkonium internal state ¢, fixing the294

Table 1. Decay width for 'Ij;' ---+ J /'Ij;7r7r and Y' ---+ Y7r7r inunit keY.
mode'Ij;' ---+ 'lj;7r7r
Y' ---+ Y7r7r

2.5

F omn

F=l

expo

260

70
0.64

135 ± 20
12 ± 4

2.3

(a)

~

~

1 .5

~
0.5

0.2

0.4

0 .6

0.8

x =(M",,-2m,,)/(m2S-m1 S-2m,,)

2.5

(b)

~

~

1 .5

~
0 .5

0 .2

0.4

0 .6

0.8

x=(M",,-2m,,)/(m2S-m1 S-2m,,)

Fig. 1. Distribution of the invariant mass m7T7T for (a) '1/;' ---+
J/'I/;7r7r and (b) Y' ---+ Y7r7r decays. Data are taken from
Fig. 7 of Ref. 3. The solid (dashed) line indicates theresult without (with) the form factor F .

parameters with the binding energy EO = 2mD -2mJj'f/;
and me = 1.5 GeV for J/'I/J (similarly for Y). The
resulting decay widths listed in Table 1 agree withthe experimental values within a factor of 5. In ourframework, the shape of the pion invariant mass distribution is determined mainly by the matrix element\7r7rIE . EIO). Based on Fig. 1, we find the need for aform factor which enhances the rate in the 0.5 GeV region, as well as the importance of the chiral symmetry
constraint which suppresses the rate in the thresholdregion. Note that we did not attempt any fitting inthis calculation.
This result suggests that our simple framework correctly describes the process of quarkonium interactions
up to a factor of 5. However, it is known that the process Y(3S) -4 Y(lS)7r7r has a different feature compared to that shown in Fig. 1; accordingly, it seems
that other elements need to be included.
References
1) H. Fujii and D. Kharzeev: Phys. Rev. D 60 , 114039(1999), and references therein.
2) M. Voloshin and V. Zakharov: Phys. Rev. Lett. 45, 688(1980).
3) H. Albrecht et al. (ARGUS): Z. Phys. C 35,283 (1987).

8. Miscellaneous

RI KEN Accel. Prog. Rep. 34 (2001)

Topological Modes of Solidification in Liquids
with a Confined Geometry
S. Ishimoto,*l T. Kobayashi,*2 K. Morimoto,*l I. Nomura,*3 S. Suzuki,*lY. Takahashi,*4 I. Tanihata, and T. Tsuru*l
On cooling liquid hydrogen, argon, nitrogen andneon in a small copper cell from the upper side, we
found new modes of solidification with topologicalnatures,l) i.e., an evolution of a "solid string" and apileup of half-ellipsoidal solid films inside the liquid.
The string continued to develop as a three-dimensionalknotwork in the liquid surrounded by the solid growing on the cold sidewall until the entire liquid solidified. The string was found to have a structure with abubble front and a following tubular solid. Therefore,
these modes are understood as ways of forming void
spaces in a confined liquid required for contraction of
the volume during the solid growth. When these liquids were solidified in a closed cell, it was expected thata porous isotropic solid would grow at the center part.
However, these topological modes and solid tubes havenot been reported to our knowledge.
The main part of our experimental apparatus was aunit of two small cells for solidification and made ofpure copper as shown in Fig. 1. The upper cell wasi

LIQUID HeHEAT EXCHANGERGAS INLET

a flat cylinder with its axis in the vertical direction.
The lower cell was a hole of 25 mm in diameter with
its axis in the horizontal direction bored in a rectangular block of copper (72 mm x 72 mm x 10 mm). Bothsides of the hole were sealed with 5-mm-thick silica
windows. A straight hole of 7 mm in diameter drilledin the copper block connected these cells. The unit was
firmly attached to a helium continuous-flow cryostat.
Gas was introduced into the upper cell through its top
flange. An appropriate amount of gas was first introduced and, then, liquid helium was slowly introduced
to the upper part of the heat exchanger.
The gas liquefied and solidified. Solidification first
took place in the upper cell and blocked the holes,
confining the liquid in the lower cell. Figure 2 showsa hydrogen string near 13.8 K. The front of the string
moved downward, forming a transparent and uniform
solid string after it. It reached then reflected off thecopper sidewall or the growing solid surface, and moved
straight ahead to the opposite side until it was reflectedagain there.
Figure 3 shows an argon string near 83.8 K. The
argon string was thick, uniform and straight. The front
part had the brightness of metallic silver, which was
clearly the total reflection. Sometimes we observed
bubbles moving upward inside the lines. This indicatedclearly that the string was a tube made of a thin solid
wall and not a solid bar. The moving bubbles inside theargon tubular string, which show the situation mostclearly, are shown in Fig. 4. A bubble appeared at thebase of the string. In the diffusive transmitted light,
the remnant seemed to be a pair of thin parallel lines

Pt-Co
THERMOMETER

INDIUM

LOWER CELLSILICA GLASSFRAME....---_~

COPPER BLOCK( 10 mm thick)Fig. 1. Experimental apparatus.
*1
*2
*3
*4

High Energy Accelerator Research Organization
Faculty of Science, Tohoku University
National Institute for Fusion Science
Research Center for Nuclear Physics, Osaka University

Fig. 2. Hydrogen string near Tt = 13.8 K.

295

Fig. 3. Argon string near T t = 83.8 K.

which appeared similar to a transparent plastic tube.
We also observed strings in nitrogen and neon liquid.
In conclusion, we observed that the liquid with aconfined geometry generally adopts several topologicalmodes of solidification, when the volume of the system must contract in the solid formation. The mostinteresting mode is the evolution of the solid string.
We found a peculiar structure of the string, in that it296

Fig. 4. Bubbles moving inside the solid tube of string inliquid argon.

consists of a bubble front and a following solid tube.
References
1) S. Ishimoto, T. Kobayashi, K. Morimoto, I. Nomura,
S. Suzuki, Y. Takahashi, I. Tanihata, and T. Tsuru:
RIKEN-AF-NP-354, KEK Preprint 2000-42 H, to be
published.

RIKEN Accel. Prog. Rep. 34 (2001)

Possible Mobile TeV Muon Source for Disasters Prevention
K. Nagamine
For the purpose of probing the internal structure ofa very large object such as a volcanic mountain, thenear-horizontal cosmic-ray muons with energies higher
than Ge V, produced as secondary cosmic rays by theinteraction of the primary cosmic-ray protons in the atmospheric air, are most suitable (range of 1 TeV muonin a rock mountain: 1 km) , provided that the size ofthe detection system is realistically large for a limited
muon flux (10- 2 j(cm 2 . s . str . TeV) at 1 TeV). The
basic idea of the method can be summarized as follows: a) The cosmic-ray muon energy spectrum andits dependence on the vertical zenith angle are almost
unique. b) The range of cosmic-ray muons throughthe mountain is uniquely determined by electromagnetic interactions. c) Thus, the intensity of cosmic-ray
muons (NJ.L) penetrating through rock with thickness
X is uniquely determined. d) The cosmic-ray muon
path through the mountain can be determined by employing a position-sensitive detection method. Basedon test experiments conducted at Mt. Tsukuba 1 ) and
Mt. Asama, a new method for the prediction of volcanic eruptions via the detection of near-horizontal
muons passing through the active part of the volcano
has been proposed.
In order to overcome the intensity-limitation problem, it is indispensable to consider the use of an accelerator. A reasonable way to obtain a mobile TeV
source might be to produce muons using the somemodest low-energy proton accelerator and accelerate
the thus-produced muons up to TeV by employing an
acceleration scheme developed in either 11+ 11- colliders
or in a neutrino factory.
It is also interesting to point out that many of theactive volcanoes are situated near the seaside. Thus,
an on-ship mobile 1 TeV accelerator, if it is realized atall, will be the most powerful tool to explore a time-dependent change in the inner structure of a volcano.
A "compact" and mobile Te V muon source canbe realized by employing various new acceleration
schemes and the ultraslow muon method. 2 ) Here, we
consider the most compact scheme of TeV muon source
to be realized by the presently available technologies
and consider mounting--it onto a "mobile" aircraft carrier ship.
The scheme shown in Fig. 1 is currently proposed.
For the muon production, a compact proton accelera-~e~~:nSIOW

I/

Generation

HeV Muon
Recirculation
Linac

SOm

Fig. 1. Schematic view of a mobile 1 Te V muon source.

Table 1. The expected performance of the mobile Te V muon source.

Expected numbers

Conditions(s-I)

Nil -stoP
Nth.MuN u.s.ll +N ~''.f(1 TeV)

Remarks

1.9 X 10 12
2.4 X lOll

0.8 GeVX31lA
4cm Carbon

6.0 X 109

Pion Capture: 2.9 T, 20 cm bore X 1.5 m
Muon Decay: 3.0 T, 25 cm bore X 10 m
20 X 100 IlmW

Ref. [4JP : 88(42) MeV

c: th.Mu: 0 .04
c: ion : 0.8

2000 KhotW
Laser Resonant Ionization

2.9 X 109
1.2 X 108
LO X 108108

a t~~ : 28 mb

Il

c: cap. : 1.0
c: acc. : 1.0;!: total7r + at production target, NIl+ : total 11+ at the exit of decay solenoid, N ~top : W stopping number atthermal Mu producing material, N th.Mu : thermal Mu yield, Nu.s.ll+ : ultra-slow W yield after thermal Mu ionization.

N297

tor either a conventional synchrotron or a FFAG (fixed
field alternating gradient) synchrotron up to 1 GeV will
be used. There, with minimum use of proton linac, acompact synchrotron can be constructed within a circular space of 50 m diameter. Then, following the installation of a super-super muon channel with a large
acceptance and superconducting pion collector and asuperconducting decay solenoid,3) the ultra-slow /-l+generation setup will be installed using hot tungsten
for thermal muonium (Mu) production and laser resonant ionization of the Mu. 2 ) The thus-realized intenseand high-quality muon ion source will have various advantages for further acceleration up to TeV energy: (1)an extremely small phase space, and (2) a small energy
spread (±0.2 eV).
A compact linac will be employed to accelerate /-l+from 0.2 eV to 4 GeV. Then, a recirculating accelerator
as realized for the electron accelerator at CEBAF will
be used to accelerate /-l+ from 4 GeV to 1 TeV. According to the latest arguments,4) the entire installation

298

will require the space shown in Fig. 1. A small energy
spread is very helpful for a compact design of the "arc"for the recirculation linac. The expected performanceof the proposed muon accelarator is summarized in Table 1; easily a 10 10 increase will be realized from thevalue for cosmic-ray muons referred at the beginning.
The required space should be compared to the spaceof 80 m x 350 m available for the existing Kitty Hawk
air craft carrier.
The author thanks Dr. G. Reece for helpful discussion and Dr. K. Shimomura for providing the drawing.
References
1) K. Nagamine et al.: Nucl. lnstrum. Methods Phys. Res.
A 356, 585 (1995).
2) K. Nagamine et al.: Phys. Rev. Lett. 74, 4811 (1995).
3) K. Ishida and K. Nagamine: KEK Proc. 98-5 II, (1998),
p.12.
4) J. S. Berg: AlP Conf. Proc. 580, p.13 (2000).

IV. NUCLEAR DATARI KEN Accel. Prog. Rep. 34 (2001)

Measurement of Neutron Production Cross Sections
by High-Energy Heavy Ions
H. Sato,*1 H. Iwase,*1 T. Nakamura,*1 T. Kurosawa,*2
N. Nakao,*3 and Y. Uwamino
We measured the double-differential cross sections(DDX) of neutrons from thin C, AI, Cu, and Pb targets
bombarded by 135 MeV /nucleon C, Ne, and He ions,and by 95 MeV/nucleon Ar ion.
The experimental spectra were compared with thecalculation using the two heavy-ion Monte Carlo codesof the internuclear-cascade and evaporation model(HIC) 1) and the quantum molecular dynamics model(QMD).2)
The measurements were carried out in the E4 experimental room in the RIKEN Ring Cyclotron. A
schematic view of the experimental setup is shown in
Fig. 1. The NE213 liquid scintillator (12.7 cm diameterby 12.7 cm thick), which was designed to expand the
dynamic range of output pulses for high-energy neutron measurements, was used as the E counter, andthe NE102A plastic scintillator (15 cm by 15 cm squareand 0.5 cm thick) used as the f:j.E counter was placedin front of the E counter to discriminate charged particles from noncharged particles, neutrons and photons.
The target thicknesses are 1 mm of C, 0.6 mm of AI,
0.3 mm of Cu, and 0.3 mm of Pb. The direction of
the incident beam was rotated around the target fromo to 110 degrees using the beam swinger, in order
to measure the energy-angle distribution of neutrons
produced from the target by the time-of-flight (TOF)
method having the flight path of 847 cm. The measurements were carried out at 0, 15, 30, 50, 80, and
110 degrees.
Figures 2 and 3 show the experimental and calculated neutron energy spectra. The neutron energy
spectra measured in the forward direction have a peaknear the projectile energy per nucleon. This peakis due to a knock-on process in which a neutron isknocked out by the direct collision between the target nucleon and the projectile nucleon. This peak becomes more prominent in the forward direction and fora lighter target. The high-energy end of neutrons in
the forward direction reaches about 300- 400 MeV.
Two calculations using HI C and QMD show a tendency to underestimate the high-energy neutron components beyond the peak. At large angles, the calculated spectra are in good agreement with the measured
spectra. In general, the QMD gives better agreementwith the experimental results, especially for a heavy
target, than the HIC.

*1

*2
*3

Tohoku University
Electrotechnical Laboratory
High Energy Accelerator Research Organization

110 deg

Flight path 847cm

Fig. 1. Schematic view of the experimental setup.

1000

...co

<:

o

~ 0.001
co
co

..,~

10-5

100

1000

neutron energy [leV]Fig. 2. Double-differential cross sections for 135 MeV jnucleon C ion on Pb target.

1000

..
~

0. 1

!

IS 0. 001

¥..
~

10-5

100

1000

neutron energy [leV]Fig. 3. Double-differential cross sections for 135 MeV jnucleon Ne ion on C target.

References
1) H. W. Bertini, T. A. Gabriel, R. T. Santoro, O. W.
Hermann, N. M. Larson, and J. M. Hunt: ORNL-TM4134 (1974).
2) J. Aichelin: Phys. Rep. 202, 233 (1991).

299

300

V. DEVELOPMENT OF ACCELERATOR FACILITIESRIKEN Accel. Prog. Rep. 34 (2001)

RI Beam Factory Project: Progress Report
Y. Yano, T. Katayama, A. Goto, and M. Kase
Figure 1 shows the layout of the Radioisotope Beam
Factory (RIBF) which is under construction as an extension of the RIKEN Accelerator Research Facility(RARF). This new facility will add new dimensions
to the RARF's existing capabilities. At present, theRARF has a world-class heavy-ion accelerator complex.. ACR
...
.. ..
.. ..

consisting of a K540-MeV ring cyclotron (RRC) andtwo types of injectors: a variable-frequency Wideroelinac (RILAC) and a K70-MeV AVF cyclotron (AVF).
Moreover, its projectile-fragment separator (RIPS)
provides the world's most intense light-atomic-mass
RI beams. In the factory, a new cyclotron cascade

Phase II

Phase I

Experimental Room

Existing Facility:
RILAC: Frequency-variable Heavy-ion Linac,
CSM: Charge State Multiplier,
RRC: K540MeV Ring Cyclotron,
AVF: K70MeV AVF Cyclotron,
RIPS: Projectile Fragment Separator.
RIBF Phase I:
SRC: K2500MeV Superconducting Ring Cyclotron,
IRC: K980MeV Ring Cyclotron,fRC: K520MeV Fixed-frequency Ring Cyclotron,
BigRIPS: Projectile Fragment Separator.
RIBF Phase II:
ACR: Accumulator Cooler Ring,
e-RI Collider: Electron-RI Beam Collider.

Fig. 1. The layout of the RI Beam Factory (RIBF). The first phase of the RIBF is now under construction
and will be completed in 2003. The construction of the second-phase building, the layout of which ispreliminarily depicted here, is planned to begin in 2002 and will be completed in 2005.

301

consisting of a K510-MeV fixed-frequency ring cyclotron (fRC) , a K980-MeV intermediate-stage ring
cyclotron (IRC) and a K2500-MeV superconducting
ring cyclotron (SRC) will be the post-accelerator forthe existing RRC. This new cyclotron system will
be able to boost the RRC beam's output energy to
400 MeV /nucleon for light ions and 350 MeV/nucleon
for very heavy ions. The goal for the beam intensity ishigher than 1 pf-LA.
As in the existing RIPS, RI beams will be generated
mostly by projectile fragmentation. In addition, inflight fission of a uranium beam will be used for theefficient production of very neutron-rich isotopes in themedium mass region. A BigRIPS will be installed togenerate such RI beams with much grater magnetic
rigidity.
The RIBF includes the multi-use experimental storage rings (MUSES) consisting of an accumulator cooler
ring (ACR) and an electron-RI beam collider (e-RI
Collider). The MUSES will enable us to conduct various types of advanced experiments: electron scatteringon unstable nuclei, precision mass measurements, andatomic physics with cooler electron beams. In the original MUSES project, ion-ion merging or head-on col-302

lis ions and X-ray spectroscopy of unstable nuclei areplanned. We will be requesting the budget to realize
these as an RI-beam application program.
The construction of the RIBF is scheduled to be implemented in two phases: in the first phase, the new
cyclotrons and the BigRIPS will be built, and the RIbeam experimental installation and the MUSES will
be constructed in the second phase.
The construction of the first-phase building, and thefabrication of the IRC, the SRC and the BigRIPS will
be completed early in 2003. In 2003, the overall installation and final tuning of these machines will be
carried out. We will submit the budget for the fRC in
FY2002, and we expect to install this cyclotron during
the above-mentioned final tuning work. The first RIbeam production by the BigRIPS is scheduled for thespring of 2004.
The construction of the second-phase building will
begin in 2002 and will be completed in 2005. After its
completion, major experimental installations, e.g., alarge acceptance spectrometer and a gamma-ray detector, will be realized. The ACR will be commissioned
in 2006. The first electron scattering experiment on
unstable nuclei is scheduled for 2009.

RIKEN Accel. Prog. Rep. 34 (2001)

Dependence of Beam Intensity on Plasma Electrode Size and Position
for RIKEN 18 GHz Electron Cyclotron Resonance Ion Source
Y. Higurashi,* T. Nakagawa, M. Kidera, Y. Miyazawa, M. Hemmi,
T. Chiba, M. Kase, T. Kageyama, A. Goto, and Y. Yano
In the last decade, we have applied many kinds oftechniques to increase the beam intensity of highly
charged heavy ions produced from the RIKEN 18 GHz
electron cyclotron resonance ion source (ECRIS), e.g. ,by gas mixing, the biased electrode method, the wall
coating method and so on, and successfully increased
the beam intensity of highly charged heavy ions. 1) This
year we focused on the effects of position and size ofthe plasma electrode on the beam intensity produced
from the RIKEN 18 GHz ECRIS, and studied theseeffects systematically.
Details of the design and performance of the RIKEN
18 GHz ECRIS are described in Ref. 1. Figure 1 showsa cross-sectional view of the RIKEN 18 GHz ECRIS.
The axial confinement of plasma is achieved using twosolenoid coils which generate a magnetic mirror field.
The mirror ratio has the nominal value of 2.8. The
maximum magnetic field strength in the axial direction is 1.4 T. To achieve the radial confinement ofplasma, we use a hexapole magnet. The field strength
at the surface is about 1.4 T, the operational frequency
is 18 GHz and the maximum RF power is 1.5 kW.

In this experiment, to investigate the effect of theelectrode position, we measured the beam intensities
of Ar ions at two positions, A and B, as shown in
Fig. 1. At electrode position A, we measured the beam
intensity using plasma electrodes with different holesizes (8 , 10, and 12 mm in diameter) to investigate theeffect of hole size.
Figure 2 shows the beam intensities of Ar ions at
the two electrode positions. It is clear that the beam
intensity of Ar 8 + increases from 600 to 750 ep,A , whenchanging the electrode from A to B. In this experiment, the extraction voltage was 12 kV, the typicalgas pressure was 1.2 x 10- 6 Torr, the RF power was
530 W. Incontrast, the number of highly charged Ar
ions, such as Arll+ and Ar I2 + , decreases dramatically.
The beam intensity of highly charged heavy ions isstrongly dependent on the electrode position. An optimum electrode position to maximize the beam intensity of multi-charged Ar ions may exist.
Figure 3 shows the beam intensities of Ar ionswhen using electrodes with different hole sizes. Lower
charge-state Ar ions (Ar 8 +) increase with increasing
hole size. However, the beam intensity of the higher
charge state Ar ions (Ar I2 + and Ar 13 +) does not depend on the size of the hole, and is almost constant.
From this experimental result, we may conclude thatthe higher charge-state Ar ions, such as Ar12+ andAr 13+, stay in the central part of the ECR plasma,
while, the lower charge-state Ar ions, such as Ar 8 + ,exist over a wide area of the ECR plasma.

60 0

'<
2,

~
~

:5

4 00

~

III

200

I.
:

.1

Position A l l
125mm
1

1
1

:..

1

Position B
135mm

1

Plasma chamber

1

.1

:

Fig. 1. Cross-sectional view of the RIKEN 18 GHz ECRIS.

10Charg e State of Ar

12

14

Fig. 2. Beam intensities of Ar ions at two electrode positions (A and B).

Rikkyo University

303

References

6001) T. Nakagawa, Y. Miyazawa, M. Hemmi, T. Chiba, N.
Inabe, M. Kase, T. Kageyama, O. Kamigaito, A. Goto,
and Y. Yano: Jpn. J. Appl. Phys. 35, L1124 (1996) andreferences therein.

12¢

'<
3
>.

400

~

E
~

~

8¢

200

12
Charge State of Ar

14

Fig. 3. Beam intensities of Ar ions when using the electrodes of different hole sizes.

304

RIKEN Accel. Prog. Rep. 34 (2001)

Investigation of Bias Disk Effect in RIKEN 18 GHz ECRIS under
the Pulsed Mode Operation of Bias Voltage
Y. Higurashi,* T. Nakagawa, M. Kidera, Y. Miyazawa, M. Hemmi, T. Chiba, M. Kase,
T. Kageyama, A. Goto, and Y. Yano
Last decade, many laboratories attemped to increase
the beam intensity of highly charged heavy ions prod uced by Electron Cyclotron Resonance Ion Sources(ECRIS), using many techniques. 1) One of them isthe biased electrode method. Although this method
is used successfully in many laboratories, the mechanism to increase the beam intensity is still unclear.
In order to investigate the mechanism of enhancement of the beam intensity using an electrode, several
experiments have been conducted. 2- 4 ) One of them isthe time-resolved measurement. 2) In this experiment,
the Frankfurt group found that the ion current reacted
promptly against a change of the bias. From this experimental result, they concluded that the bias disk
effect is mainly due to the improvements of the extraction conditions at the source. In our experimental
results , however , it is clearly seen that the distributions of highly energetic electrons were affected by thebiased electrode 3 ) and that beam intensity is strongly
dependent on the position of electrode. 4 ) In spite of thegreat success of this method, the mechanism is still unclear. To investigate the mechanism in detail, we conducted a new experiment to learn the time response of
the beam intensity. For this test experiment, an electrode (18 mm in diameter) was installed in the plasmachamber of the RIKEN 18 GHz ECRIS, as shown in
Fig. l.
Initially, to check the dependence of the beam intensity of highly charged heavy ions on the negative bias
voltage and the position of the electrode, we have supplied the negative bias voltage in the continuous voltage mode (DC mode). Figure 2 (a) shows the beam
intensity of Ar 8 + ,11+ ions as a function of electrodeposition. The gas pressure was 2 x 10- 6 Torr. The extraction voltage and RF power were 12 kV and 400 W,
respectively. Figure 2 (b) shows the beam intensity of
Ar 8 + as a function of negative bias voltage at the electrode positions of L = 3.31 and 6.67 cm. The electrodeposition of L is defined in Fig. l. The beam intensity
increases with increasing negative bias voltage up to-50 V and then decreases at L = 3.31 cm. It corresponds to the position of maximum magnetic fieldstrength (Bmax) on the axial direction. On the other
hand, at L = 6.67 cm, the beam intensity gradually increased with increasing bias voltage from 0 to -200 V.
Generally speaking, the negative bias voltage which
gives the maximum beam intensity gradually increases
with increasing L.
Rikkyo University

5o Electrode position (L)(cm)

Fig. 1. Cross-sectional view of the RIKEN 18 GHz ECRIS
with bias disk.

To get information on the response time of the
ECRIS to the bias voltage, we made time-resolved
measurements of the beam intensity when supplying
the negative bias voltage the time structure shown in
Fig. 3 (a). The maximum and minimum bias voltage
were kept at 0 and -50 V , respectively, at the electrode position L = 3.31 cm. We changed the tlt from1 s to 1 ms without changing any other ion source parameters (e.g., magnetic field strength, RF power, gaspressure and extraction voltage). this indicates thatthe value of I:::.. VI tlt was changed from 0.05 V Ims to
50 V Ims. If the response time of the beam intensity to
the bias voltage is very fast, as described in Ref. 2, thetime structure of the beam intensity should not change
under the present experimental conditions. However,
it is clear that the time structure of the beam intensityof Ar 8 + was changed at 10 ms, and the saturation timeof beam intensity is delayed at less than I:::..t = 10 ms,
as shown in Fig. 3 (a). From this experimental result,
it is concluded that t he response time of the extracted
beam to bias voltage is slower than 10 ms at the electrode position of L = 3.31 cm under this experimen-

305

1000

o A11+
r
• A~+

1
.!..

<:::t

,!!.100400
3.31cm

~ 300

~
en
c

';

.5
E

.E
E

C

S

.!
I'CI

200

CIS

10

Q)

G)

CD

m 100

-300
2.0

4.0

6.0

B.O

-200

-100

0

Bias Voltage (V)Electrode Position (cm)Fig. 2. (a) Beam intensity of Ar 8 +.1 1+ ions as a function of electrode position. (b) Beam intensity of
Ar 8 + as a function of bias voltage at the electrode position of L = 3.31 and 6.67 cm.

Imax
Beam intensity

/

a)

~~~~~
V= 0--50V
'iii'
E

20

~ 16

.1.T=15 msq+b)~T=20 ms

~
G)
G)

Co

III

I

Ar
L=6.67cm

12

G)

III
C

.1.T=10 ms

Y=

0
Co

III

8

G)

a::

4
~T=5 ms

Time (ms)

7

8

9

10

11

Charge State (q)Fig. 3. (a) Time structure of the beam intensity of Ar 8 +. (b) Fastest response time of the beam intensityof highly charged Ar ions to bias voltage at the electrode position L = 3.31 and 6.67 cm.

tal condition, which corresponds to .6. VI.6.t = 5 V Ims.
At L = 6.67 cm , we observed that the response timeof Ar 8 + was slower than 5 ms , which corresponds tothe 20 V Ims. Figure 3 (b) shows the critical value of.6. VI.6.t (it is defined as the value at which the saturation time of the beam intensity starts to be delayed.) for highly charged Ar ions at two positions.
The response time of the extracted beam near the ECR
zone is much faster the those in the Bmax region. It
is also observed that the response time become fasterfor higher charge state heavy ions. The electrons fromthe biased electrode may change the electric field in
the plasma. From these experimental results, it may
be concluded that the biased electrode does not affectthe density of ECR plasma, but simply increases theflow rate of highly charged heavy ions to the extracted306

region of ion source.
References
1) R. Geller: Electron Cyclotron Resonance Ion Sources
and ECR Plasma (lOP, Bristol, 1996) and references
therein.
2) K. E. Stiebing et al.: Phys. Rev. ST: Accel. Beams.
(WEB) 2, 123501 (1999).
3) M. Kidera, Y. Higurashi, T. Nakagawa, S. Biri, G.
Shirkov, M. Hemmi, T. Chiba, M. Kase, T. Kageyama,
A. Goto, and Y. Yano: Proc. 14th Int. Workshop on
ECR Ion Sources (CEARN, Geneva, 1999), p.86.
4) S. Biri, T. Nakagawa, M. Kidera, Y. Miyazawa, M.
Hemmi, T. Chiba, N. Inabe, M. Kase, T. Kageyama,
O. Kamigaito , A. Goto, and Y. Yano: Nucl. Instrum.
Methods Phys. Res. B 152, 386 (1999).

RIKEN Accel. Prog. Rep. 34 (2001)

Status of Liquid He Free Super Conducting Electron Cyclotron
Resonance Ion Source
T. Nakagawa, T. Kurita,* M. Imanaka,* M. Kidera, T. Kawaguchi, and S.-M. Lee*
Recently, for the production of intense beams ofhighly charged heavy ions, two ECR ion sources havebeen constructed in RIKEN and U nversity of Tsukuba.
At RIKEN, one of the new ion sources will be used to
inject an intense beam of highly charged heavy ions,such as Kr and Xe, to the RIKEN AVF cyclotron. In
the University of Tsukuba, the ion source will be used
to study dynamic behaviors of metal clusters, such as
fission and multifragmentation.1) In this paper, we report the structure and initial results of using the new
ECR ion source operated in the Unversity of Tsukuba.
The design of the ion source is described in detailin Ref. 2. Figure 1 shows the cross-sectional view ofthe liquid-He-free SC-ECRIS. The superconducting
solenoid coils are cooled in a small Gifford-McMahon
type refrigerator at temperatures below 5 K. The refriderator maintains the superconductivity of solenoid
coils without requiring a supply of liquid He. Thesesolenoid coils are used to supply the mirror magnetic field to confine the plasma in the axial direction.
The hexapole magnet which consists of 24 segmentsof permanent magnets is used to confine the plasma
in the radial direction. The maximum strengths ofthe mirror magnetic field are 3 and 2 T at the microwave injection side (Binj ) and the beam extracG·M refrigeratorstion side (B ext ), respectively. The minimum magnetic
field strength of the mirror magnetic field (Bcenter) isapproximately 0.3 T. The inner and outer diametersof the hexapole magnet are 80 and 174 mm, respectively. The maximum magnetic field strength at the
inner surface of the plasma chamber is 1 T. The innerdiameter of the plasma chamber is 72 mm. To protect the hexapole magnet from demagnetization due
to high temperature, the plasma chamber wall has adouble-wall structure to allow the flow of cooling water. The injected microwave frequency is 14.5 GHz.
The maximum power is 2 k W. For the production of
Xe ions, we used enriched 136Xe gas (enrichment of85%). As the gas mixing method is very effective forall elements which have heavier masses than that ofcarbon, in the present case, we used oxygen gas as the
mixing gas. Also, a negatively biased electrode placedin the plasma chamber is utilized to increase the beam
intensity.3) The electrode is a circular disc (25 mm indiameter) made of stainless steel.
Figure 2 shows the typical charge-state distributionof Xe ions when the ion source was tuned to produce
Xe 30 + ions. The beam intensity of 10 eJ-LA for Xe 30 +ions was obtained at an injected microwave power of
650 Wand an extraction voltage (V ext ) of 15 kV. The
beam intensity of Xe 30 + ions produced from liquidHe-free SC-ECRIS is almost the same as those produced from the two ECRISs (upgrade version of theadvanced ECRIS in Lawrence Berkeley National Laboratory (AECR-U)4) and SC-ECRIS in the Laboratorio Nazionale Sud, Catania (SERSE)5)), which can
produce one of the highest beam intensities of highly
charged ions in the world. Comparing our results with-

1~~+ionc(::i

RF power 650 W
Vexl
15 kV

.!,
~30

.;
C

04+

S
.5
.......1Mr'[~UU lis)

Microwave Injectionside~______________~jde

1m

2

M/q
Fig. 1. Cross-sectional view of liquid-He-free SC-ECRIS.
University of Tsukuba

Fig. 2. Charge distribution of Xe ions. The ion source wastuned to produce Xe 30 + ions.

307those of the two ECRISs, our results are very remarkable, because an injected microwave power higher than
1.2 kW was required to obtain almost the same resultsin the other two ECRISs.
References
1) F. Chandenzon, C . Guet, B. Huber, D. Jalabert, M.
Maurel, E. Monnand, C. Ristori, and J. Rocco: Phys.
Rev. Lett. 74, 3784 (1995).

3082) T. Kurita, T. Nakagawa, T. Kawaguchi, and S.-M. Lee:
Rev. Sci. Instrum. 71 , 909 (2000).
3) For example, S. Biri et al.: Nucl. Instrum. Methods
Phys. Res. B 152, 386 (1999).
4) Z. Q. Xie: Rev. Sci. Instrum. 69, 625 (1998).
5) S. Gammino, G. Ciavola, L. Celona, M. Castro, F.
Chines, and S. Marietta: Rev. Sci. Instrum. 70, 3577
(1999).

RIKEN Accel. Prog. Rep. 34 (2001)

Plasma Measurements on the Pulsed High-Power Microwave
Ion Source at RIKEN
S. Bhattacharjee, T. Nakagawa, M. Kase, A. Goto, and Y. Yano
We have undertaken the development of a novel
pulsed high-power microwave ion source at RIKEN 1,2)
with a view to obtaining intense, multicharged, pulsed
ion beams. This ion source employs short-pulse (0.051.0 j.Ls), high-power (",100 kW) microwaves of 9.45 GHz
which are launched into a circular conducting tube
with a radius smaller than the cutoff value (cutoff frequency ",9.77 GHz), which forms the plasma chamber.
The plasma is confined by a minimum-B field generated by permanent magnets surrounding the tube,
in the form of a multicusp (10 poles) with a lengthof 30 cm and inner diameter of 7 cm. The absenceof axial magnetic fields generated by electromagnetic
coils makes the device compact. A modification of
the plasma refractive index at the tube entrance helps
the high-power waves to propagate through the peripheral plasma region 3- S ) with a reduced wavelength,
thereby overcoming the geometrical cutoff limitation.
The narrow tube dimension enhances the microwave
power density (rv 100 kW /cm 2 ), which favors the production of a high-density plasma (> the cutoff density)with a high electron temperature. 4- 6)
Our recent measurements 2 ) using argon as the test
gas indicate that the plasma build-up is extended beyond the end of the pulse, with the peak density attained several tens of j.LS later in the power-off phase, as
shown in Fig. 1, where the end of the microwave pulse
is also indicated. In general, the plasma build-up time
T.p, defined as the time to obtain the peak density fromthe end of the pulse, increases with increase in pressure. Depending on the pressure and the microwave
power, the ionization frequency in the power-off phasecan be sufficiently high so as to balance the plasma
losses by recombination and diffusion. This results ina density flat-top that is maintained for several tens ofj.Ls , as shown in Fig. 2, and is a unique feature compared to conventional afterglows. These results indicate the generation and maintenance of a high electron temperature in the plasma even in the poweroff phase, conforming to our previous time-resolved
measurements 4 ,S) and recent numerical simulations,6)
which indicate that at lower pressures (collision frequencies V c ~ (0.1 - 1) x 10 9 s- 1), electron temperatures of several keY are obtained and the temperature build-up continues beyond the end of the pulse.
Multiply-charged states can be produced by the Augeror electron shake-off processes 7 ,8) during the transienthigh-power pulse when the electric field is strong, while
stepwise ionization would be predominant in the interpulse regime where the plasma is still active. Bothprocesses are important for the generation of multiply

Fig. 1. Temporal variation of the electron current density
J e with pressure p as a parameter.

• (po)

Fig. 2. Temporal variation of the electron current density
J e ) showing the development of a density flat-top in theinterpulse regime. The discharge pressure pis 36 mTorr
and the pulse repetition frequency fr = 100 Hz.

charged states.
Under pulsed operation, the gaseous breakdown conditions in the narrow tube 9 ) (plasma chamber) is an
important factor which determines the operating pressure of the ion source. The breakdown threshold depends on the ionization energy of the gas, the characteristic diffusion length (which is a function of the
tube radius), the pressure and the source frequency.
Breakdown occurs initially at the tube entrance by
the evanescent electric field. The spatial extent ofbreakdown was estimated 9 ) from the microwave discharge theory, and for important waveguide modes,
TEll, TMo1 and TE o1 , from the requirements of thethreshold electric field. It was found that the breakdown extent is the longest (rv6 cm) in the case of the
TEll mode, followed by that of the TMOl (rv 1 cm)
and TEOl (rvO.5 cm) modes. A numerical calculation 9 )of the radial distribution of the electric field indicatesthat the TEll and TMOl modes peak at the tube center while the TEOl mode peaks half way to the chamber wall. These results are important for investigatingplasma production and density uniformity in the chamber. Figure 3 shows the variation of the peak (electron)

309

!.

!,

10
-0-

248Hz

- - 1 00Hz
•

50 Hz

Solid Syrnbol l ; J_Open symbob: t.

-0-. 25 Hz

Trianp: 30 mTorr
Inlt:rpulle llme limit ~~i ~T:!OIT

I

P

100
p (Torr)

Fig. 3. Variation of the peak electron
current density J m e with pressurep and pulse repetition frequency
ir as a parameter.

p(Tl,lrr)

Fig. 4. Variation of the electron confinement time Ie with pressure p
and pulse repetition frequency iT
as a parameter.

current density Jme with pressure p and pulse repetition frequency ir as a parameter. The plasma can besustained at a pressure range of 10- 3 Torr- 1 Torr, andfor this condition a maximum current density of approximately 100 mA/cm 2 can be obtained. It is notedthat for lower values of ir (:::; 50Hz), the current isuniform over a wider pressure region.
The particle confinement time was investigated from
temporal measurements of the currents in the interpulse (power-off) phase of the high-power microwave
pulses. Without external energy to sustain the plasma,particle generation occurs by ionization due to the highelectron temperature and losses occur due to volume
recombination and diffusion to the walls. Particles are
confined by the bottle structure of the minimum-B
magnetic field and the plasma space potential whichpeaks at the tube center. The electron confinement
time I e may be taken as the sum of the build-up time
Ip and decay time Id. Id is defined as the time required
for the electron current to decay from its peak value
to a zero level current when measured with the highest sensitivity (",0.1 p,A). Figure 4 shows the variationof Ie with pressure p and pulse repetition frequency
ir as a parameter. I e was found to increase steadily
from ",0.1 ms at 3 mTorr to approximately 10 ms at 40
mTorr, which was the maximum value. Beyond thispressure, Ie decreased and then tended to be ",3 ms at
1 Torr.
The pulse repetition frequency ir was found to influence the plasma properties at a lower pressure. Figure 5 shows the variation of J me and I e with ir andpressure p as a parameter. At a lower p (7 mTorr and
10 mTorr) both J m e and I e are seen to increase rapidly
with in however, above 10 mTorr (e.g., 30 mTorr) the
dependence on ir seems to be small. Above 100 Hz , Ie
is seen to decrease, this is because of the limitation in
the measurement of Ie due to a smaller interpulse time.
The transition is marked as "Interpulse time limit" inthe figure.

310'.( H~)

Fig. 5. Variation of the electron confinement time I e and the peakelectron current density J m e withpulse repetition frequency iT andpressure p as a parameter. Solidsymbols: J m e , open symbols: I e
and triangles: 30 mTorr , squares:
10 mTorr and circles: 7 mTorr.

High-power pulsed ion sources of the present typehave applications to areas where there is a requirement for intense multicharged pulsed ion beams. The
achievement of high electron temperature both within
the pulse and its maintenance after the end of the pulse
will be favorable for the generation of multicharged
ions within a short interval of time. The capability tooperate at a higher pressure is another advantage, andwill be useful in applications where a close coupling of
the ion source is required in areas having large pressure gradients, such as where it is required to tolerate
vapor loads greater than 10- 4 Torr. The possibility ofobtaining Jme ~ 100 mA/cm 2 at 10 mTorr indicatesa high ionization efficiency even at higher pressures.
This is due to the realization of a high microwave power
density in the narrow tube. The electron confinement
time of about 104 times greater than the pulse duration will be favorable for the production of higher
charged states by having an increased interaction timeof energetic electrons with ions.
References
1) S. Bhattacharjee et al.: RIKEN Accel. Prog. Rep. 33,
200 (2000).
2) S. Bhattacharjee, T. Nakagawa, and Y. Yano: Bull. Am.
Phys. Soc. 45, 230 (2000) .
3) S. Bhattacharjee and H. Amemiya: Jpn. J. Appl. Phys.
37, 5742 (1998).
4) S. Bhattacharjee and H. Amemiya: J. Phys. D: Appl.
Phys. 33, 1104 (2000).
5) S. Bhattacharjee and H. Amemiya: Vacuum 58, 222(2000).
6) S. Bhattacharjee, H. Amemiya, and Y. Yano: J. Appl.
Phys. (2001), in press.
7) A. Septier: IEEE Trans. Nucl. Sci. 19, 22 (1972).
8) T. A. Carlson and M. O. Krause: Phys. Rev. A 140,
1057 (1965).
9) S. Bhattacharjee, H. Amemiya, and Y. Yano: Bull. Am.
Phys. Soc. 45, 369 (2000).

RIKEN Accel. Prog. Rep. 34 (2001)

First Beam Measurement of Laser Ion Source at RIKEN
T. Takeuchi,*1 T. Katayama,*1 T. Nakagawa, M. Okamura, K. Yano,
B. Sharkov,*2 and S. Kondrashev*2
At RIKEN RI Beam Factory, the maximum intensityof primary beams from the Super-conducting Ring Cyclotron (SRC) is assumed to be 1 pf..LA. In order to obtain more exultant results in the MUSES project,l) an
upgrade of the beam intensity will be one of the mosteffective efforts, and thus is the most required. Therefore, we are developing a laser ion source (LIS)2,3) as a
new dedicated pulsed ion source for the MUSES. The
average charge state of ions in the expanding laser
plasma strongly depends on power density [W / cm 2]
deposited by laser beam. 4 ) To obtain sufficient power
density to produce highly-charged-state ions in our LIS
system, we optimized the gas mixing ratio, the laser
pulse shape and the focal spot size. We then maximized the power density and measured the beam current for the condition of no extraction potential.
A transverse electric atmospheric (TEA) CO 2 laser 5 )(wavelength: A = 10.6 f..Lm) with the energy of 10 J andthe repetition rate of 10 Hz is chosen as a driver for the
LIS. Excitation to the laser transition level of 10.6 f..Lm
is provided by glow discharge in the gas containing
CO 2 , N 2, and He. Therefore, the laser output energy
and repetition stability depend on the gas mixing ratioof CO 2 , N 2, and He. In addition, the optimal condition for gas mixing is different for individual CO 2 laser
systems because the discharging characteristic of thepreionization and the pumping strongly depends on
the shape of the electrodes and the volume in which
the gas is contained. 6 ) For these reasons, we measured
the mean energy and the stability of the energy for
20 shots using several gas mixing ratios of CO 2 , N 2,
and He, as listed in Table 1. We obtained the maximum output energy of 12.1 J for the gas mixing ratioof CO 2 : N2 : He = 1: 2: 4, and the best stability for thegas mixing ratio of CO 2 : N2 : He = 1: 1: 8.
The pulse shape of the CO 2 laser was measured using a photon drag detector. The typical laser pulse
shape obtained is presented in Fig. 1 (a) and (b) for
different time scales. A laser pulse usually consistsof two components (a short high gain first peak anda low gain long tail). 7) Only the first peak is effective for the generation of laser plasma which produces
highly charged heavy ions. Therefore, we maximized
the total power of the first peak by varying the gas
mixing ratio (C0 2 : N2 : He = 1: 1 : 4, 1: 1 : 8, 1: 2: 4,
2: 1 : 2, 2: 1 : 4, 2: 1 : 6, and 3: 1 : 4). The best result
was obtained at the gas mixing ratio of CO 2 : N 2 : He
= 2: 1 : 4. The power ratio of the first peak to the total*1*2

Center for Nuclear Study, Graduate School of Science, University of Tokyo
Institute of Theoretical and Experimental Physics, Russia

Table 1. Laser mean energy and the stability for 20 shotsof TEA C02 laser. Total gas pressure is 1.5 kg/cm 2,
the conductance is 10liter/min and the flow is about
1800 Torr liter/sec. Air pressure in the pre-spark gap
is 1.3 kg/ cm 2 .
CO 2 :N2 :He

Mean Energy (J)

1:1:4
1: 1:8
1:2:4
2:1:4

7.41
6.71
8.16
6.96

Standard
Deviation (1)
0.73
0.51
0.80
0.58

Stability (%)
9.90
7.56
9.80
8.43

(a)

~

~Jh...
fl rl

05

1

15

2

25

Time [J.1S]
-

(b)

J

J I~

1'~
--

1

15

Time [J,ls]
Fig. 1. Typical C02 laser pulse shape ((a) rough time scale;(b) zoomed time scale).
integrated power of the laser pulse was 58 ± 3%. The
laser power of the first peak was PI = 110 ± 30 MW(the energy: El = 4.1 ± 0.6 J and the pulse duration
time is 38 ± 5 ns).
A new target chamber (Fig. 2.) designed and manufactured by ITEP was delivered to RIKEN.8,9) The
diameter and height of the chamber are 360 mm and
300 mm, respectively. N aCl is used as the input window material for the infrared laser beam. Two adjustable copper mirrors (plane and focusing mirrors)
are installed inside the chamber. The laser beam isreflected by the plane mirror and then focused by aconcave mirror with a focal length of 135 mm. The
distance between the focusing mirror and the target
surface is changeable without breaking the vacuum. A

311

200

i:l
Q)

150

A

100

I\

t::::s
u

i:l
Q)
E
Q)
I-<

::s

50
0

c;f.)

C>I

To

- - - - - - - _ ..._--_•. _--------_....._--._-.-----

<'
~

~

~

-50

~

\

~
25

50

75

100

Time [/Js]
Fig. 3. Faraday Cup signal for the suppressor potential of-2 kV. The target material is aluminum. The Faraday
cup is located at a distance of 3250 mm from the target.
Fig_ 2. Schematic view of a new target chamber with arotatable target and two copper mirrors.

target rotation mechanism enables us to operate sequentiallaser shots in the order of 10 4 times on a new
surface. The focal spot size (2dj) of the CO 2 laser obtained using this target chamber is 44 j.Lm. Our CO 2
laser has an unstable resonator and does not produce
a Gaussian-shaped beam. Therefore, we adopted another factor , 50%, for the laser power, as suggested ina Ref. 2. Using this factor , we can estimate the valueof the power density on the target surface asI~~~

27fd j 2 'Substituting P 1 and dj, the power density obtained forour experimental setup is 9 x lOll W /cm 2 .
In the setup mentioned above, we measured thebeam current with a Faraday CUplO) located 3250 mm
away from the target. The measured data is shownin Fig. 3. The electrode potential of the Faraday cup
was -2 kV. The target material was aluminum. The
first peak (consisting mainly of highly-charged-stateions) and a very small hump (consisting mainly of lowcharged-state ions) were observed at about 2 j.LS and

312

about 8 j.LS , respectively. The measured current for the
first peak was 180 j.LA . The current of the first peakcorresponds to the ion current density of 230 j.LA/cm 2 .
The energy and pulse duration time of the ions for the
first peak were about 551 eV /u and 10 j.LS (FWHM) ,respectively. We are planning to increase the beam
current using other types of the extraction system forthe ion source. 2 ,1l)
References
1) T. Katayama et al.: MUSES Conceptual Design Report
2000, Internal Report.
2) T . Katayama et al. : MUSES Conceptual Design Report
2000 , Sect. 2, Internal Report.
3) T . Takeuchi et al.: RIKEN Accel. Prog. Rep. 33, 202(2000) .
4) B . Sharkov et al.: in Handbook of Ion Sources, edited
by B. Wolf, (CRC Press, Boca Raton , 1995) , p.149 .
5) T. Takeuchi et al.: Proc. EPAC2000, (2000) , p.1622.
6) V. Yu. Baranov et al.: Preprint of Kurchatov InstituteIAE-2398 , Moscow, Russian , 1974.
7) R. Scrivens: Doctoral Thesis, May 1999.
8) S. Kondrashev et al.: Rev. Sci. Instrum. 7 1, 1409
(2000) .
9) S. Kondrashev et al.: Proc. EPAC2000, (2000) , p.551.
10) T . Takeuchi et al.: CNS Annu. Rep. 1 999, 36.
11) M. Okamura et al.: Proc. EPAC2000, (2000) , p .848.

RIKEN Accel. Prog. Rep. 34 (2001)

Development of Long-Lived Carbon Foil
for Charge Stripper in RILAC
H. Hasebe,* l 1. Sugai,*2 and M. Kase
The production of long-lived C-foils (carbon foils) forthe charge stripper of heavy-ion beams has been very
important for present heavy-ion accelerators in the
RIKEN Accelerator Research Facility (RARF) and it
will be more urgently required for the RIKEN RI-Beam
Factory (RIBF) project. We have decided to produce
C-foils ourselves because the commercially available
foils do not satisfy our requirements.
At the end of 1999, a high vacuum evaporation system (EBX-2000C by ULVAC) was purchased and installed in the RILAC building as shown in Fig. 1.
The system has a vacuum chamber with a volume of
750 mm x 750 mm x 900 mm and has two oil-sealed
pumps and a 5000l/s cryogenic pump. The ultimate
vacuum pressure is 1.0 x 10- 5 Pa and it takes less than
15 minutes to evacuate the chamber from atmosphericpressure to 1.3 x 10- 4 Pa. In March of 2000 , we started
to produce C-foils with an ac and a dc arc discharge
evaporation source.
After production of the C-foils, their durability under beam irradiation was measured. The beam was
136Xe9+ with an energy of 32 keY /nudeon and a sizeof 5 mm x 5 mm. Attention was paid to forming a uniform beam that was as long as possible. C-foils with athickness of 10 mg/cm 2 were tested. Under these con-ditions, the lifetime of commercially available C-foils(Arizona Carbon Foil Co.) with the same thickness islimited to within 60 s. The angle between the direction of arc discharge and the foil surface was variablefrom 0 to 45 degrees. Figure 2 shows the result of the
lifetime of a C-foil depending on the angle of arc discharge. The C-foils have long lifetimes in the cases ofodegrees for the ac discharge and 30 degrees for the dc
one. Next , six types of graphite from three companies
were tested as a source of the C-foil. The results areshown in Fig. 3. The best results were obtained in thecase of OT-5200N(S) for ac discharge and EG-20SH
for dc discharge. Figure 4 shows the result depending upon the discharge current. The lifetime becomes
longer as the discharge current is increased. The lifetime of C-foils depends upon the parting agent. Threeo DC300A• AC300Ao

4S

30
Discharge angle (degrees)Fig. 2. The result of C-foil lifetime dependence on the
direction of arc discharge. Zero degrees corresponds tothe discharge direction parallel to the foil surface.

o AC300A.DC300A

.,

.,

.E
~

:.J

Fig. 1. High vacuum evaporation system (EBX-2000C by
ULVAC).
*1

SHI Accelerator Service, Ltd.

*2 High Energy Accelerator Research Organization (KEK)

EG-20SH

EG-30XSH ER-38NSH

ER-38SH

OT5200N(S)G140Type of graphite

Fig. 3. The dependence of C-foil lifetime on the type ofgraphite.

313

2000 . - - - - - - - - - - - - - - - - ,1800 1 - - - - - - - - - - - - -..........
___-----i./'
1767
1600 I -_ _ _ _ _ _ _~--..c..------I
1400

3: 1200

1--------~""---------1~1347__________--1

1--_.....IiII:;~~

1230
E 1000 1 - - - - - - - - - - - - - - - - - 1.Z'~

800 1 - - - - - - - - - - - - - - - - - 1
600 1 - - - - - - - - - - - - - - - - - 1
400 1 - - - - - - - - - - - - - - - - - 1
200 1 - - - - - - - - - - - - - - - - - 1

o ~---~----~----~
100

200
AC discharge current (A)300

Fig. 4. The dependence of C-foil lifetime on the ac discharge current.

314

parting agents (LaCL 3 ) NaCI, and NiCb) were tested
and NiCl 2 was found to be preferable. The lifetime was
improved by 20% when a dc arc discharge was appliedwith N2 gas flow.
We have obtained a C-foil with a lifetime 40 times
longer than the standard one. We are expecting an
increase of durability by an additional twenty percent
soon.

RIKEN Accel. Prog. Rep. 34 (2001)

Development of Liquid Film Charge Stripper
H. Akiyoshi, T. Chiba, M. Kase, and Y. Yano
Charge strippers are widely used in heavy ion accelerators. Commonly used methods are foil stripping and gas stripping. Gas stripping has the advantages of causing less energy straggling and less multiple scattering, and being able to withstand intense
heavy ion beams, but has the disadvantage of producing lower average charge states than foil stripping.
Foil stripping has the advantage of producing higher
average charge states but has the disadvantage thatit breaks down with short lifetimes under bombardment by high-intensity heavy ion beams according tostructural changes induced by radiation damage andpossibly beam heating. I) With higher intensity andhigh-mass beams of RIBF, the foil lifetime is expected
to drop markedly to as low as one minute. Substantial
progress has been made in developing carbon foil production techniques that result in foil lifetime enhancement factors of up to 2 orders of magnitude as compared to foils fabricated by the conventional method. 2 )A different approach to solving the stripper foil lifetime
problem was first suggested by Cramer et al., 3) anduses a thin free-standing oil film spun from the edge ofa razor-sharp-edged rotating disc touching the surface
of an oil reservoir. Leemann et al. 4 ) developed anotherliquid film stripper based on the same concept. The
status of the liquid film charge stripper system in thedeveloping stage for RIBF based on the same concept
is described here.
Figure 1 shows a conceptual diagram of the liquidfilm production apparatus. A disc with diameter 9 cm
is rotated by the magnetically suspended motor of aturbomolecular pump. The motor has been modified
to be frequency tunable. The lower edge of the disc is
immersed in a reservoir of silicone oil. We used SH200
silicone oil with kinematic viscosity of 50 cSt, as suggested in Refs. 3 and 4. The reservoir is suspended byslide rods so that the depth to which the disc is immersed in oil is adjustable over a range from zero toabout 3 cm. A 'scraper' is mounted on a separate po-sitioning mechanism so that it can be moved ±2.5 cm
in horizontal direction and ±4 cm in vertical direction.
The disc, the oil reservoir and the 'scraper' are placedin a vacuum chamber.
At first, we adopted a disc such as those used inRefs. 3 and 4, and observed the three types of films
described in Ref. 3. If the disc is immersed very deeply
in the oil, a thick film of large area can be produced
when the disc is rotated at a very low frequency. Thesefilms exhibited no distinguishable optical interference
pattern. The next type of films showed strong interference colors and were of small area. The third typeof films was observed to flicker in and out of existence,and showed a large area comparable to the first typeof films .
We succeeded in making films with strong interference colors and large area by changing the shapes of
the rotating disc and the 'scraper. ' Higher rotating
frequencies of the disc generally produced larger areas with the thinnest bands, as described in Ref. 4.
We observed an area in which no interference color appeared at the upper edge of the film upon increasing
the rotating frequency and using oil of lower viscosity.
Therefore, the thickness of the thinnest part of the film
was assumed to be about 0.3 p,m.
The stability of the film became worse when the rotating frequency was increased. One possible sourceof this instability is disc vibration. We measured thevibration of the disc using an inductive displacement
sensor, and found that the displacement in the normal
direction against the disc was as large as about 50 p,mwhen the disc was rotated at 30 Hz. It is likely thatthe vibration is large when the disc is rotated at 30 Hz ,because the motor we adopted is normally operated ata much higher frequency when it is used for the rotation of a turbomolecular pump rotor. The present
rotation mechanism has another problem as its size is
too large to arrange the beam duct. Modification of
the rotation mechanism is in progress.

Fig. 1. Conceptual diagram of liquid film charge stripper.

1) E. Baron: IEEE Trans. Nucl. Sci. 26, 2411 (1979) .
2) 1. Sugai, M. Oyaizu, H. Kawakami , C. Ohmori, T.
Hattori, K. Kawasaki , M. J. Borden, and R. J. Macek:
Nucl. Instrum. Methods Phys. Res. A 362, 70 (1995).
3) J. G. Cramer, D. F. Burch, R. Rodenberg, and P. B.
Cramer: Nucl. Instrum. Methods 185 , 29 (1981).
4) B. T. Leemann , P. Merrill, H. K. Syversrud, R. Wada,
and R. B. Yourd: IEEE Trans. Nucl. Sci. 28, 2794
(1981) .

References

315

RIKEN Accel. Prog. Rep. 34 (2001)

Construction of a Test Cavity for Sliding Rf Contacts
O. Kamigaito, N. Sakamoto, E. Ikezawa, Y. Miyazawa, T. Chiba, M. Hemmi, S. Kohara,
A. Goto, M. Kase, Y. Yano, K. Uno, * and T. Sakata*
Sliding rf contacts or contact fingers, are indispensable for frequency-tuning mechanisms in rf cavities,
such as movable shorting-plates and tuners . A typical rf contact is illustrated in Fig. 1. The main bodyof the contact is a finger-shaped metallic plate, which
is usually made of copper-beryllium alloy and platedwith silver. On the surface of each finger , one or twopieces of silver tips are welded. The plate is fixed on
the boundary of the shorting plate, and the silver tips
are pressed onto the cavity wall by the elasticity of thefingers. When the electric current across the silver tips
is large, pneumatic cylinders are used from the back of
the fingers to press the tips firmly. At present , various
types of rf contacts are commercially available in different sizes and materials. The guaranteed limit of suchcontacts against the current density is around 60 Alcm
at maximum for rf frequencies below 100 MHz.
There is a growing demand for the sliding rf contacts
which can withstand much higher current density.l ,2)However, it has been very difficult to examine the limitations of the contacts against the rf current density
precisely; conventional measurements with dc-currents
do not give substantial information. Therefore, a test
cavi ty has been constructed for the development of therf contacts for the high current density.
Figure 2 shows the schematic drawing of the test
cavity. It is based on the folded-coaxial structure,
which gives a low resonant frequency with compact
dimensions. 3 ) The design was made using the computercode MAFIA.
Almost all the components of the cavity are madeof oxygen-free copper. The sliding rf contacts are seton the shorting plate surrounding the inner conductor.
Pneumatic cylinders for the contacts are also preparedon the shorting plate. The water channels are arranged
based on the heat calculation. The total water flow is
52 I/min. The cavity is equipped with a turbomolecu-

lar pump of 350 lis.
According to the MAFIA calculation, the current
density reaches 100 Alcm when the gap voltage is
210 kV. The gap voltage is monitored with the calibrated signal from the loop pickup on the base plate.
Therefore, the current density is deduced from the
pickup signal during the operation. There are fiveviewing ports for monitoring the contacts. Two ofthem are located in the ceiling plate and the otherthree are on the sidewall.
Table 1 shows the rf characteristics of the cavity.
The measured resonant frequency is in good agreementwith that using the MAFIA calculation. The measured
Q-value is about 75% of the calculated ones. From
this result, the estimated power loss is 39 kW for thecurrent density of 100 AI cm.
This cavity can be also used for the investigation of
the sparking under a high rf voltage. The top pieceof the inner conductor can be replaced by an electrodewhich has the same shape as the drift tube of the CSM
cavities. 1 ,4) When the distance between the electrodeand the trimmer is 20 mm, the surface electric fieldreaches 16 MV 1m for a gap voltage of 120 kV. This
field strength is the same as that required in the CSM, shortingplate

E-field test

pneumatic cylinder.'~

metallic plate

o
I

I

2

3

4

I

I

I

I

o
I

I

20 em
I

feederFig. 2. Schematic drawing of the test cavity.
cavitywall

movable shorting plate

5 em

I

Fig. 1. Conceptual drawing of an rf contact.
Sumitomo Heavy Industries , Ltd.

316

10

Table 1. Frequency and Q-value of the test cavity.
f calcQ ca lc

69.0

fm easQmeas

Qm eas /Q ca lc

9,600

(%)
69.0

(MHz)

(MHz)
13,90069.8

cavities.
The test cavity is already set in the RILAC building.
High-power tests have just started using one of theamplifier systems for the CSM.5)
References
1) O. Kamigaito et al.: RIKEN Accel. Prog. Rep. 33, 206(2000) .

2) N. Sakamoto et al.: RIKEN Accel. Prog. Rep. 32, 208(1999) .
3) O. Kamigaito et al.: Rev. Sci. Instrum. 10, 4523 (1999).
4) O. Kamigaito et al.: RIKEN Accel. Prog. Rep. 34, 322(2001).
5) Y. Murakami et al.: Proc. 12th Symp. on Accelerator
Science and Technology, Wako, (1999), p.239.

317

RIKEN Accel. Prog. Rep. 34 (2001)

New Control System for the RIKEN Ring Cyclotron Using EPICS
M. Kobayashi-Komiyama, I. Yokoyama, M. Kaji,*l M. Sugimoto,*2
M. Nagase, T. Tanabe, and M. Kase 'In the last progress report, we reported the necessityof renewing the present control system of the RIKEN
Ring Cyclotron (RRC).1) One reason for this is somecurrent operational problems, mainly occurring aroundthe touch panel, man-machine interface recently, andthe other reason is the request to expand the system toachieve compatibility with the RIKEN RI Beam Factory (RIBF) project. To maintain compatibility withthe present control system, a partial system replacement plan has been under investigation since last year
by using the Experimental Physics and Industrial Control System (EPICS).2) Considering the fact that the
RRC is constantly in operation, the system replacement must be carried out in stages. Under the present
condition of RRC operation, we cannot take a sufficiently long period at anyone time to replace the large
quantity of low level control parts. Therefore, we areattempting to replace only the high level control partsof the system, including the touch panel as the firststage, and the low level control parts are being left
as they are. However , by this replacement method,
the maximum control ability of the present equipment
is expected to be realized. The actual replacement isplanned for the end of March 200l.
In Fig. 1, the part surrounded by the dashed line
is newly introduced to the system to replace the minicomputer, Mitsubishi M60/ AR, which is the host computer in the present system. Our present system isbased on a CAMAC serial crate network and is supported by two types of modules, communication in-

terface modules (CIMs) and device interface modules(DIMs). These modules were originally developed by
RIKEN in order to assist the main computer in its
tasks. Almost all magnet power supplies and beam diagnostic devices such as beam profile monitors, beambaffies, beam slits, main differential probes and Faraday cups are controlled by them. As shown in Fig. 1,
only high level control parts are replaced in the firststage of the system replacement. This means that the
low level control parts including a CAMAC loop areleft as they are and they must be controlled by EPICS.
In the EPICS control system, VME single board computers are used as Input/Output Controllers (IOCs),
which function as distributed servers of EPICS. EPICS
IOC applications consist of the IOC core, record support , device support and driver support. When using
hardware not currently supported by EPICS, a hardware driver and/or device support routine needs to becreated. Since CIM and DIM are our original modules ,the device supports to control them must be developedby us.
On the other hand , we create graphic user interfaces (GUls) for operation on the EPICS Workstation (EWS) which is used as the Operator Interface(OPI). The EPICS protocol between IOC and OPI iscalled the Channel Access (CA) protocol. The CA
client applications run on OPls such as Motif-based
Editor/Display Manager (MEDM) and Archiver (AR,EPICS logging tool). In our new system, we create
GUls by using MEDM/DM2K if our objective opera-

Partial Replacement Plan Using EPICS

Ethernet
10BaseTNEW!

Accelerator System'--_ _-.r-C_AM_A_C_L_0-li0p. (Optical Fiber) )'--_4o_o_m_ _ ...-_--J#1

W

OPtlc~;:-m ,. #7 ~ .

f ..'MagnetPower Supply

I. , Max 12-,30m t~IOIMI IOIMI

IOIMI

IBOil

•

I

BOA unit

Beam Diagnostics

I

Vacuum, Cooling, RF

Fig. 1. New control system using the EPICS.
*1
*2

318

Mitsubishi Electric Corporation
Mitsubishi Electric Control Software Corporation

Data

CapFast(CAD Tool)

MEDM(EPICS Tool)

EPICS
Template~DM

Template

SWC~~=(MEDMDef.)

Operation
Window

I_I

Fig. 2. Sample of GUI created by using MEDM.
Fig. 3. EPICS configuration generation.

tions are realized using the objects prepared in them
(DM2K is the upgraded version of MEDM, which wasdeveloped by BESSy3»). As mentioned later, the configuration files of the operation windows on MEDM areautomatically generated using data stored in an Oracle
database. When we require more complex functions on
GUI, we must create them by writing programs in C.
In the new system, we prepared programs to show thegraph of data measured by a profile monitor, a Faraday cup and a main differential probe. Though MEDM
has a graph object, it has functions which are too simple for our requirements. However , for the present,
almost all operation windows were created by MEDM.
Figure 2 is a sample GUI created by MEDM for thecontrol of a magnet power supply.
Also as shown in Fig. 1, we newly introduced Oracle
to our system. We planned to consolidate all accelerator system data on this relational database management system. It concretely manages the properties of
the control devices such as the device name, control
address and specifications .
The preliminary system for controlling the magnet
power supplies, profile monitors and Faraday cups of
the RRC was tested last year, and we obtained results
which indicated that the fundamental operations could
be performed using EPICS. This year , we are testing
the operation of all the accelerator devices which arecontrolled by the CAMAC-CIM/DIM system. In orderto do this, the EPICS database file must be preparedfor each operation; the details of this are mentioned
in Ref. 4. This is a text-based configuration file of
the real-time process database in the IOC core, and isgenerated from an EPICS template file and an EPICS
parameter file. Figure 3 shows the scheme for generating the EPICS database files and the MEDM definition files automatically from the Oracle database.
The EPICS template file has the control logic for specific types of equipment such as magnet power supplies
and profile monitors. There are two files for controlof the magnet power supplies, and eight files for eachbeam diagnostic device, and some for others in the system now. On the other hand, the EPICS parameter

file has a set of parameters for each existing device.
They are automatically created by programs written
by PL/SQL in Oracle. The parameters in this file are
required by its related EPICS template file.
At present, almost all RRC devices connected to
the CAMAC-CIM/DIM system can be controlled by
EPICS. Now we are examining how to maintain theoperational log, and we are attempting to use AR.
Moreover, we have also decided to replace the highlevel control part of the RILAC control system by using EPICS as well as the RRC. In the present RILAC
control system, the same minicomputer is used in thesame position as in the RRC system. Therefore, thecontrol of the devices in the RILAC will be made possible only by adding the operational data into the Oracle
database. However, it is available only for the devices
controlled by the CAMAC-CIM/DIM system. The RILAC has a more complex control system than the RRC
because of its longer history. Some devices are controlled by the CAMAC-CIM/DIM system as well as
the RRC system, while others are controlled by a GPIB and a programmable logic controller (PLC), and a
network I/O (NIO) system in the future. As the firststage of the investigation of the RILAC system replacement , we are attempting to operate the magnet power
supplies controlled by GP-IB by EPICS. There are no
significant differences in the construction of the EPICS
database between a CAMAC-CIM/DIM system and a
GP-IB. The device supports will be developed for each
GP-IB device, and their operation will be tested fromthe same GUI as the CAMAC system. The results ofthe test have not been obtained yet. We continue theinvestigation of the RILAC control system as well as
the RRC control system.
References
1) M. Kobayashi-Komiyama et al.: RIKEN Accel. Prog.
Rep. 33, 204 (2000).
2) http://www.aps.anlgov /epics/3) http://www-csr.bessy.de/control/4) M. Kaji et al.: Proc. 12th Symp. on Accelerator Scienceand Technology, Wako , (1999) , p.441.

319

RIKEN Accel. Prog. Rep. 34 (2001)

CORBA-EPICS Server
T. Tanabe, T. Masuoka, and M. Kase
The common object request broker architecture(CORBA)l) is the standard distributed object architecture for an open software bus, which allows object components created by different operating systems(OSs) and languages to interoperate. We have investigated the possibility of using CORBA for communication in the new control system for Radio Isotope Beam
Factory (RIBF). 2) Riken Accelerator Research Facility(RARF) controls are currently being upgraded with
Experimental Physics and Industrial Control System(EPICS)3) so a mechanism must be developed to allow
for the old and the new controls to communicate witheach other. CORBA is often used to integrate legacy
systems with various kinds of wrapper softwares. However, in our case, it is easier to set up a gateway computer which acts as a translator between the two systems. The CORBA-EPICS (CE) server scheme fulfils
this need.
The CORBA server used for the test is the one used
for the main-coil power supply of an intermediate-stage
ring cyclotron (IRC). The version of EPICS installed
in a Sun Workstation (UltralO Model 360, Solaris 2.6)
is R3.13.2 and a portable channel access (CA) server
program runs in it. The ORB is VisiBroker 4 ) for C++ver. 3.3. Sun Workshop3 C++ 4.2 was used for thecompiler. Since CORBA and EPICS environments are
in different network segments, some routing operationis required. Figure 1 shows the system configuration
for this server.
The characteristics of the developed software are as
follows:

The operation from EPICS to CORBA is initiatedby a CA client. It specifies the records to process in
the CE server and a modified portable CA server program passes data to the CORBA client program in it.
This CORBA client connects CORBA servers in the
CORBA domain. A sample program (excas) has been
modified to accommodate the following functions in
the CA server:• To make new record-type definitions for CORBA
operations.
• To determine the necessary CORBA operation forthe corresponding record type.
• To get/put necessary records for a CA client.
• To stop scanning the record when the task is finished.
From CORBA to EPICS, the CORBA client has toknow the records to be accessed in the CA server inthe EPICS domain. After the CORBA server program
receives the call from the CORBA client, it calls a
CA client in the CE server to connect to CA servers
in the EPICS domain. Schematic diagrams of both
operations are given in Fig. 2 (a) and (b).
The interface definition language (IDLs) defined in
the CORBA part are in the following.
module C_ E_ SERVER {interface CORBA_to_EPICS
any EpicsGet( in string Str_Epics);• Fully multithreaded operation is performed to allow simultaneous operation from both directions.

long EpicsPut( in string Str_Epics); }; };• It is possible to read, write and execute in either
direction.
• The CORBA client knows the record name anddata so that the CORBA server calls the CA clientto access the CA server.
Network Selllentl

Network S.....,t2 : - (IP:.... 8I...... YYY(IP: •••.•8I..... xxx)- :~bbb.bbb.bbb.xxx)
I

I
I
I
I

any

CorbaGet( in string Str_ Corba );long

CorbaPut( in string Str_ Corba); }; };:- Network s.....t3i (lP:bbb. bbb. bbb. yyy)

:

I
I

:

Fig. 1. CORBA-EPICS server system configuration.

320

(8)

From EPICS(b) From CORBA
Realtime
DataBase

I

I

•

2

6

3-------.t Realtime

11. . . _C_A_--,
7----.J CI i ent

DataBase

leAl~:Se~.r: I
3

5

2

4

Fig. 2. (a) Schematic diagram of EPICS to CORBA operation. 1. The client accesses a record (put/get).
2. The record accessed is referred to by the CA server program (put/get). 3. The data set in therecord are delivered to the CORBA client program (put/get). 4. Received data are delivered to the
CORBA server (put/get). The data from the CORBA server returns to the CORBA client (get) .
5. & 6. A reply from the CORBA server is reflected in the record (get). 7. The CA client gets a
result from the record (get). (b) Schematic diagram of CORBA to EPICS operation. 1. The record
to be accessed is specified in the CORBA server (put/get). 2. Received data are delivered to the CA
client (put/get). 3. Data are put to or get from the specified record (put/get). 4. Acquired data aredelivered to the CORBA server (get) . 5. The data are delivered to the CORBA client via CORBA(get) .

The "any" data type has been chosen for these operations because there are several different data types
allowed in EPICS calls.
There are a few aspects to be modified if the CE
server is used in real controls. First, data consistencies
have to be monitored and maintained in some ways if"put" operations from both sides are permitted. Second, in this test, it was assumed that one record contained one piece of data. It is necessary to modify

the CORBA part of programs if multiple data such asarrays are used for the record .
References
1) http://www.omg.org/
2) http://accelconf.web.cern.ch/accelconf/eOO/PAPERS/TUP4B15.pdf
3) http://www.aps.anl.gov /epics/docs/4) http://www.inprise.com/

321

RIKEN Accel. Prog. Rep. 34 (2001)

Construction of the High-Energy Part of the CSM
O. Kamigaito, N. Sakamoto, M. Kase, E. Ikezawa, S. Kohara, M. Hemmi,
Y. Miyazawa, T. Chiba, Y. Chiba, A. Goto, and Y. Yano
As reported in the last issue,1) the low-energy partof the charge-state multiplier (CSM) was constructedbased on the quarter-wavelength resonator, which has
shown good rf characteristics such as a wide variabilityof the frequency and high Q-values. This year , thehigh-energy part of the CSM was designed based on
the same principle, and the resonant cavities of theaccelerator section were constructed.
Figure 1 shows a conceptual drawing of the CSM.
The "unit" of the CSM is a combination of two accelerator cavities and one decelerator cavity. The numberof units has been reduced to three , while it was fourin the original design,2) because of the lack of space in
the RILAC building. Although the maximum energy
at the charge stripper decreases by 20% compared tothe original value, a uranium beam of one particle microampere will still be available at a final energy of
100 MeV /u.
The acceptable charge-to-mass ratio (A/q) of thehigh-energy part of the CSM was chosen to be thesame as that of the first unit. Using the CSM frequency j, A/q of the accelerator cavities is 32 ,000/ j2 ,which gives the same limitation as the RILAC , andthat for the decelerator cavities is expressed as A/ q =16,000/ j2. The input and output energies of each tank
Charge-State Multiplier (CSM)

A6
~ AS
''-::
.~

"2A4
.9

are proportional to the square of the frequency. Table 1
summarizes the coefficients of this relationship.
Each cavity in the same unit · has the same shapeand dimensions except for the drift tubes. The number of gaps of the third-unit cavities is chosen to be
six while the others are eight , so that the cavity length
can be made less than 1.3 m. The required gap voltages are approximately 500 k V , as shown in Table 1,
which might be a critical condition for the cw-mode
operation.
Schematic drawings of the cavities of the high-energy
part are shown in Figs. 2 and 3. The dimensions were
optimized using the MAFIA code. The stroke of theshorting plate was determined so that the frequency
range from 36 to 76.4 MHz could be covered. The estimated current density on the sliding contacts aroundthe shorting plate is 60 A/ cm at maximum.
Before making the full structure, the lower parts of
the accelerator cavities were constructed , as shown in
Figs. 2 and 3. They are operated at a fixed frequencyof 75.5 MHz. All the components except for the baseplate of the cavity are made of oxygen-free copper. Thebase plate is made of steel which is plated with copper by 50/--tm. An important point in this structure isthat the cavity wall is cut from a single piece of copper block in order to avoid possible vacuum leakage
and to keep the machining accuracy. The drift tubes
have an inner diameter of 35 mm and an outer diameter of 55 mm. They are aligned within an accuracy of±0.15 mm. The water channels are arranged based on
the heat calculation. The total water flow per tank is6001/min. Each cavity is equipped with a turbomolecular pump of 520 l/s and a cryogenic pump of 4000 l/s.
Table 2 summarizes the rf characteristics of the cavities. As shown in Table 2, the measured frequencies
are in good agreement with those obtained by MAFIA

e A3
11
Q)

~ A2

Table 1. Design parameters of the high-energy part of the
CSM.

AI

-- 1.05 MeV/u ---- --

RRC

RILAC

U 49+
100 MeV/u

Fig. 1. Conceptual drawing of the CSM. The cavities are
represented by open circles. The numbers in the circles
indicate the "unit" of the CSM. The energy and frequency are chosen for the uranium acceleration up to
100 MeV lu after the SRC, as an example. The stripping efficiency in the CSM is 12% in this case.

322

Tank

G in

a

G out

b

Vgap

Lgap

(kV)
(mm)
7.71
470
93
A3
6.78
7.71
470
A4
8.65
99
6.78
470
96
D2
8.65
104
A5
8.65
9.40
500
10.16
108
A6
9.40
500
106
D3
10.16
8.65
500
a: The mput energy IS gIVen by
E in (MeV lu) = G in X f2 X 10-4,
where f is the CSM frequency in MHz.
b: Same as a but for the output energy.

Table 2. RF characteristics of the high-energy part of the
CSM.

Designed (A3, A4, D2) : 36 - 76.4 MHz variable

Tank
Height (mm)j calc (MHz)

A3
747
73.5
32,00075.5
25,0000.78
67

Q ca lc(MHz)

j rneasQm ea sQm ea s /Q calc
Plos s

(kW)

A4
734
73.5
31,00075.5
24,200
0.78
72

A5
820
73.5
31,00075.5
23,700
0.76
63

A6
812
73.5
30,00075.5
23,1000.77
67( 5.85 MeV/u ( Nq < 5.6»
Side View,

Front View[. :'3-', (D3) W

A6
Vl
<)

I

.=.~

(designed)· ·:01... A4
0

I
I

~
"8

~

()

U

Constructed (A3, A4) : 75.5 MHz fixed><:~- :.~2~.: (D2) Q
OJ

AS

~.
~.

A3

U

-< A2
Al

Fig. 2. Schematic drawing of a second-unit cavity.

RRC
Rll..AC/-- - - - - - - - - - - - - - - - - - - - - ----- - - - - - - - - - - - - - - - \Designed (A5, A6, D3) : 36 -76.4 MHz variableoIfull strucutre
c....

0

lower part

existing .... :design only

Fig. 4. Present status of the CSM.

Side View,

Front View

- - - - - - - - - - - - - - --- -- - - - - - - - - - - - - - ---- - - - - - - , ,cavity are around 70 kW at maximum, which can besupplied by the existing power amplifier. 3 )The cavities of the high-energy part, as well as thoseof the first unit, have already been settled in the RILAC building. High-power tests of the cavities havebeen performed since September 2000. The installation of various utilities 4 ) and the beamline5 ) is also inprogress. The present status of the CSM is illustrated
in Fig. 4. By using the accelerator cavities, ions whichhave a mass-to-charge ratio of less than 5.6 will be accelerated up to 5.85 MeV lu. The first beam test is
expected to be performed in the spring of 2001.
References

Constructed (A5, A6) : 75.5 MHz fixed\_- - - - - - - - - - - - - - - - - - - - - - - --- - - - - - - - - - - - - - - - ,Fig. 3. Schematic drawing of a third-unit cavity.

prediction. The measured Q-values are about 70- 80%of the calculated ones. The estimated power losses per1) O. Kamigaito et al.: RIKEN Accel. Prog. Rep. 33, 206(2000).
2) O . Kamigaito et al.: RIKEN Accel. Prog. Rep. 32, 191(1999).
3) Y. Murakami et al.: Proc. 12th Symp. on Accelerator
Science and Technology, Wako, (1999), p.239.
4) E. Ikezawa et al.: RIKEN Accel. Prog. Rep. 34, 3(2001).
5) N. Fukunishi et al.: RIKEN Accel. Prog. Rep. 34, 327(2001) .

323

RIKEN Accel. Prog. Rep . 34 (2001)

Indication System for Charge-State Multiplier Resonator Voltage
S. Kohara, T. Ohki,* T. Aihara,* M. Fujimaki, O. Kamigaito, and M. Kase
An indication system for the resonator voltage ofthe charge-state multiplier (CSM) 1) has been designed
and constructed in order to display the condition of theresonance voltage in the control room at RILAC. The
amplitude, the phase and the tuning of the frequencyof the resonator voltage are all controlled by control
circuit to ensure good operation of the rf system.
The CSM consists of six acceleration resonators, acharge stripper and three deceleration resonators. The
resonant frequency is varied from 36.0 to 76.4 MHz.
The maximum gap voltage of the resonator is 500 kV.
The voltage ratio of the voltage pickup to the resonator
voltages is about 3.33 x 10- 6 ; the maximum pickup
voltage is 1.67 V. Each CSM resonator has two voltage pickups; one is used as the control signal for the
automatic control system and the other is used as thevoltage indication signal. The voltage pickup on the
upstream side is connected to a selector switch througha coaxial cable to indicate the resonator voltage.
A block dia.gram of the indication system for the
resonator voltage of the CSM is shown in Fig. 1.
The system consists of a remote control unit, selector switch, dividers , oscilloscope, vector voltmeter,and personal computer control system. The remotecontrol unit is installed in the control room. The
selector switch is installed in the basement of the
RILAC vault. The remote control unit can be operated in two ways; one is manual control with theinternal mode and the other is the personal computer control with the external mode. The remotecontrol unit sends an ON/OFF signal to the selector
switch in order to choose the resonator voltage of theCSM. Other input channels of the selector switch

which do not correspond to the remote control unit
are terminated to 50 n so that interference among the
input channels does not occur due to by rf noise. In
the external operation mode, the remote control unit isconnected to the WE7000 measuring station throughan I/O module and controlled with the personal computer. The ON/OFF status of the input channel of theselector switch is shown on the display of the personal
computer. Communication between the personal computer and WE7000 measuring station is carried out
through an ethernet module.
The chosen resonator voltage and the reference signal from the synthesizer are sent to the vector voltmeter and the oscilloscope in the control room througha coaxial cable to display the amplitude and the phase.
The resonator voltage is compared with the reference
signal to measure the phase. The oscilloscope is employed to monitor the condition of the resonance voltage. The operator adjusts the control circuit of the rf
system when the resonance voltage is abnormal or unstable. Output terminals for the amplitude and thephase of the vector voltmeter are connected to theWE7000 measuring station through an isolated digitizer module. These data on the resonator voltage
are sent to the personal computer through the ethernet module for the monitoring and recording. The
recorded data are then used for parameter setting at
the start of the rf system and for analysis of the stability of the resonator voltage.
References
1) O . Kamigaito et al.: Proc. 12th Symp. on Accelerator
Science and Technology, Wako, (1999), p.233.

CSM

I----"-. ..---~ Resonator I

2-8

From synthesizer

Fig. 1. Block diagram of the indication system for the resonator voltage of the CSM.
SHI Accelerator Service, Ltd.

324

RIKEN Accel. Prog. Rep . 34 (2001)

Compact Beam Diagnostic System for CSM
M. Fujimaki and M. Kase
A beam diagnosis device for CSM (charge state multiplier) was developed. This beam diagnosis chamber is required to be compact to enable installation in
the space between the CSM accelerators which are as
small as 130 mm. Three detectors of the phase probe(Fig. 1 @) , the profile monitor (Fig. 1 @) and the Faraday cup (Fig. 1 @) as well as the gate valve (Fig. 1 ~)are installed in this chamber.
The structure of the gate valve is shown in Fig. 2.
The beam entrances to the vacuum chamber are closedwith the gate valve by one movement , simultaneously
separating the diagnosis chamber from the beam-line
vacuum. Therefore, the profile monitor and the Faraday cup can be maintained without breaking the vacuum for the beam line.
Although the profile monitor and the Faraday cup
are designed to be smaller than the former design,these two detectors cannot operate simultaneously because they share the same space in the beam center.
This is a disadvantage of this diagnosis chamber. We
plan to improve this problem beginning immediately.
Because it seldom breaks down, the phase probe isarranged on the outside of the gate valve. The phaseprobe is installed in the section of the short beam
pipe which connects the CSM cavity with the diag-nosis chamber. The phase probe has a ring electrodewith a diameter of 40 mm and a thickness of 8 mm, andits signal line exits the chamber through the vacuumsealed SMA connector whose ground side is floated.
The gate valve, the profile monitor and the Faraday
cup are actuated by air cylinders. Each air cylinder
is equipped with a speed controller so that these devices do not collide mechanically with each other. It
must be adjusted so that insertion is slow and withdrawal quick. A control circuit was designed for thesolenoid-operated valves. In the case of vacuum trouble or when an electric power down occurs, the gate
valve is closed after the profile monitor and the Faraday cup have been withdrawn completely. To guarantee this sequence there is a small buffer tank for airpressure uppers ide solenoid-operated valves when an
electric power down occurs.
The control system for the profile measurements was
improved so that the probe head will return to theoutside position immediately after the measurement isfinished.
Additionally, a limitation circuit is inCluded so thatthe profile monitor can be removed forcibly when the
Faraday cup is inserted. The Faraday cup operation
has priority in the control system, because it works as

~
,

". ~

L.U

Fig. 1. The cutting view from the diagnosis chamber.

325

f<.-. -- -- - -- -210
- --:--.1oE----""l.:!

115

!

i

j '

'

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I'

,

'I

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,

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Fig. 2. The side view of the gate valve mechanism.

a beam-stopping device in the beam interlock system.
It is designed to work in an emergency although theinsertion speed is set to be slow as mentioned above.
Scanning of the profile monitor should be programmed

326

as it starts to scan the beam if the Faraday cup in
the same space is accurately withdrawn and another
Faraday cup downstream is accurately inserted.

RIKEN Accel. Prog. Rep. 34 (2001)

New Beam Transport System of RILAC
N. Fukunishi , M. Fujimaki, E. Ikezawa, o. Kamigaito, M. Kase, and Y. Yano
We have started the construction of a new beamtransport system for RIKEN heavy-ion linac (RILAC)
in order to insert a charge state multiplier (CSM) l )system between RILAC and RIKEN Ring Cyclotron(RRC). The new beam transport system is illustrated
in Fig. 1. It has one main line and six branches. The
main line transfers ions from RILAC to RRC via CSM.
CSM consists of three separate sections: an accelerator, a charge stripper and a decelerator. The accelerator consists of six accelerating cavities (CSM AI- A6
in Fig. 1) and increases the stripping energy to produce highly charged ions required by RI Beam Factory(RIBF) project. 2 ) The bending magnet BM90 separates the desired charge state from the others by utilizing the difference in magnetic rigidity. Four successive
dipole magnets (SW, BA-A, BA-B and BM85) bend
the beams further. The total bending angle is 355
degrees. This structure produces a space for the decelerator section of CSM. The decelerator consists of one
decelerating cavity (CSM Dl) , and slows down ions totheir initial velocities so that RRC can accept themwithout changing its injection radius. The decelerated
ions are transferred to RRC using the existing beamline. The section from the charge stripper to the decelerator is designed to be achromatic and isochronous
like a ring cyclotron. These features are effective to
avoid complicated coupling of the longitudinal motion
driven by CSM and the horizontal motion caused by
the beam line magnets. The results of ion-optical studies are shown in Fig. 2.
The six branches (beam line el- e6) aim to provide beams accelerated by CSM for use in several
experiments. The maximum beam energy is now
6 MeV/nucleon whereas that of RILAC is limited to
4 MeV/nucleon. It enables us to conduct new typesof experiments in RILAC facility. The most important example is the search for super-heavy elements via
a sub-barrier fusion reaction. Experiments for superheavy elements have been performed in the El experimental hall of RRC facility using the lowest energy
beams of RRC. Because RILAC facility is more suitable for this experiment after the installation of CSM,-- - -- ------

I- -l------ ______________ __ _______ __ _______ __ ____ l _- --Fig. 1. The new beam transport system in RILAC facility is illustrated. CSM consists of six acceleration
cavities (AI- A6) , a charge stripper and a decelerator (Dl). The beam transport system has one
trunk line from RILAC to RRC and six branches for experiments. Four sets of quadrupole magnets(TQI- TQ4) are newly fabricated.

327

OP

BM90

sw

BA-A

BA-B

BM8S

Omm/6mOmm/-6m

Fig. 2. Beam envelope and dispersion are calculated forthe beam transport system from the object point (OP)to the decelerator section of CSM. The emittance assumed here is 22.47r mm· mrad for both horizontal andvertical directions. The momentum spread is assumed
to be 0.15%. Rectangular boxes represent dipole andquadrupole magnets.

OP

Fig. 3. Beam envelope and dispersion are calculated for the
beam transport system from the object point (OP) tothe target of GARIS. The emittance assumed here is
22.47r mm . mrad for both horizontal and vertical directions. The momentum spread is assumed to be 0.15%.
Rectangular boxes represent dipole and quadrupole
magnets.

the experimental setup including the gas-filled recoil
isotope separator (GARIS) was moved to RILAC facility.
In the case of GARIS experiments, we first accelerate ions using CSM and produce a waist beam at
the charge stripper position. A charge-stripping process is not necessary for GARIS experiments but emittance matching is performed there. Ions are transferred to the target of GARIS through BM90 and SW
magnets. We adopted both point-to-point and waistto-waist imaging for the section from the object point
to the target so that the beam tuning can be easily performed. The results of ion-optical studies are shown in
Fig. 3.
The maximum magnetic rigidity is limited to 2.1 Tm
for the beam lines e2 and e3 and 1.2 Tm for beam lines

328

Table 1. Specifications of newly constructed dipole magnets.

sw~~
Deflection angle (degree)
Curvature radius (m)BM90Maximum field (T)Pole gap (mm)Pole face rotation (degree)
Total number of coil windings
Maximum excitation current (A)Maximum vo1tase (V)

1.50

1.50

60
25125

60

90

30

1.4

1.6

432
200
65

BM85

60
0.8

010

1.50
0130

432
200
37

24
0.8

60
25125

432
200
42

e4, e5 and e6. In contrast, the maximum magnetic
rigidity of the beams accelerated by CSM is 4 Tm.
Beam line e1 accepts all the beams because there isno insertion of bending magnets.
The new beam transport system is mainly composedof the devices used in the old beam lines. What wehave newly constructed are three dipole magnets, four
quadrupole triplets, power supplies for the quadrupole
magnets and several beam-monitoring devices . For the
new dipole magnets, we use existing power supplies.
The specifications of the dipole magnets are summarized in Table 1. We should mention that the tape coiltechnique is used for these magnets. This technique
has been widely used for the magnets of RILAC facility to reduce power consumption and space. Because
we use the existing power supplies that were originallydesigned for magnets with tape coils, magnets withtape coils are best fitted to the power supplies. These
dipole magnets were fabricated by TOKIN.
The new quadrupole magnets (TQI- TQ4) have
two features. Firstly, the maximum field gradient is
25 T jm, which is much larger than those of magnets
used in other beam lines. A strong focusing power isrequired to focus a divergent beam produced by theRF fields of CSM. Note that CSM does not containany quadrupole magnets in its accelerating cavities.
The second is that these quadrupole magnets function
as a steering magnet. It is due to the lack of spacefor steering magnets. A dipole field is excited by applying different excitation currents to the four polesof a quadrupole magnet. To this end, we also fabricated new power supplies. The new beam-monitoring
devices are designed to be very compact and can beinserted between the accelerating cavities of CSM.
We plan to finish the construction of the beam lineby the end of this year and start beam services in J anuary 2001.
References
1) O. Kamigaito et al.: Proc. 12th Symp. on Accelerator
Science and Technology, Wako , 1999-10 (RIKEN, 1999),
p.233.
2) Y. Yano et al.: Proc. 1997 Particle Accelerator Conference, Vancouver, Canada, 1997-5 (IEEE, 1998) , p.930.

RIKEN Accel. Prog. Rep. 34 (2001)

Dipole and Quadrupole Magnets for Beam Transport System of
RIKEN Heavy-Ion Linac and RI Beam FactoryN. Fukunishi, K. Kusaka, T. Nagafuchi, H. Kouzu, T. Kubo, and Y. Yano
Seven dipole magnets and forty-three quadrupole
magnets were completed at the end of July 2000. The
specifications of these magnets are summarized in Tables 1 and 2. Two types of quadrupole magnets (Q190
and Q380) are used to focus beams accelerated bya charge state multiplier (CSM).l) Because the electric field of CSM acts as a strong defocusing lens, thefield gradient required by these quadrupole magnets is
25 T jm, which are larger than those required by otherquadrupole magnets. The remaining magnets will be
used in the beam transport system of RIKEN RI beamfactory (RIBF). The first three types of dipole magnets(DM90, DM30 and DM24) bend beams accelerated byIRe, the maximum magnetic rigidity of which is 3 Tm.
Other dipole magnets are for the beam transport system from IRC to SRC. The maximum magnetic rigidity is 4.6 Tm in this case. Q220 and Q420 magnets arecommonly used for these two beamlines. The maximum field gradient is designed to be 15 T jm, which isthe same as those of quadrupole magnets used in theexisting RARF facility. The dipole magnets are manufactured by Sumitomo Heavy Industries (SHI) and thequadrupole magnets are manufactured by Toshiba.
The specifications listed in the Tables were easily
realized by the present technology for conventional
normal-conducting magnets. All the products fulfilled

the required specifications. The deviation of the magnetic field is less than 1 x 10- 3 in the required region
for all the dipole magnets. For quadrupole magnets,
Toshiba examined the mixing of other multipole components using the harmonic coil method. Values of themultipole components relative to the quadrupole one
are typically 1 x 10- 3 .
One interesting point here is to confirm the accuracy of recent magnetic-field calculations by comparing calculations with measured data.
We determined the cross-sectional shapes of these magnets by two-dimensional magnetic-field calculations inwhich the computer code OPERA-2D was used. We
also estimated the maximum excitation currents using the computer code OPERA-3D that is very useful for three-dimensional magnetic-field calculations.
The end profile of magnets is followed by the existing magnets 2 ,3) and checked by three-dimensional
magnetic-field calculations. We adopted the BH curvesof pure iron and low-carbon iron for dipole andquadrupole magnets, respectively. These BH curves
are based on measurements.
First , we compare the uniformity of the magnetic
fields in Fig. 1. Measured data for two dipole magnets
that have the same cross-sectional shape are shownin the figure. Magnetic-field measurements were per-

110-

Table 1. Parameters of dipole magnets.

3r-----------------------------,-+-90A (DM24/0.511T)

T~~
Deflection angle (degree)

Curvature radius (m)Maximum field (T)Pole gap (mm)Pole face rotation (degree)
Size of hollow conductor (mm)Total number of coil windings
Maximum excitation current (A)Maximum voltage (V)Number of maLl.nets

DM90

DM30

DM24

DM28

DM13

90
2.0
1.50
60
24/24
013-$8
280
300
94.2

30
2.0
1.50
60
15/15
013-$8
280
300
41.1
2

24
2.0
1.50
60
12112
013-$8

27.5
3.0
1.53
60
010
013-$8

12.5
3.0
1.53
60
010
013-$8

280
300
35.6
2

280
330
55.2

280
330
29.7

Table 2. Parameters of quadrupole magnets.
T~~
Aperture (mm)

Q220

Q420

Q190

70

70

Length(mm)220Effective length (mm)

250

420
450

Maximum field gradient (TIm)
Size of hollow conductor (mm)

15
06-$3

06-<1>3

60
190
220
25
06-<1>3
63
160
23.1
8

15

Number of coil windings (lpole)

52

52

Maximum excitation current (A)

158
17.7
23

158
27.0

Maximum voltage (V)Number of ma~ets

8--+- 300A (DM24/1 .538i)~ 90A (Calc.lO.525T)

510- 4-+- 288A (Calc.l1 .538i)...•.. - 90A (OM3010.511T)...•... 300A (DM30/1.544i)-5 10- 4

Q380

60
380
410
25
06-<1>363-1 10-3~~~~~~~~~~~~~~~
194
196
198
200
202
204
206

R (em)

160
34.8
4

Fig.!. Deviations of magnetic field (tlB / B) are illustrated
for DM24 and DM30.

329

1.6 r - - - - - - - - - - - - - - - - .
1.4

20

-Data
........ Calculation

1.2
1.0

i='

-- 0.8
III

0.6
0.4

15

-0220 106"··"'0220-107-····0220-108-·_··0220-109
0220(Calc.)

•

E

~ 10
><
>..
III

5

0.2
0.0 !-'-............~..................J........................L......................-L....................o....L.......................Jo
50
100 150 200 250 300
current (A)Fig. 2. Magnetic flux density is plotted as a function of
excitation current.

formed by SHI using a Hall probe calibrated by a NMR
probe. We find that the maximum difference between
the calculation and the measured data is 3 x 10- 4 in theregion where the radius R is 200 ± 5 cm. The differenceis sufficiently small for conventional beamline magnets.
We also find that the difference between DM24 andDM30 is 2.5 x 10- 4 in the same region. This difference
results from errors in processing poles of magnets. Thisimplies that numerical errors in magnetic-field calculation may be smaller than 3 x 10- 4 .
Second, we compare the magnetic flux densities atgiven excitation currents to investigate the effectiveness of three-dimensional magnetic-field calculations.
We show magnetic flux density as a function of excitation current in Figs. 2 and 3. Magnetic-field measurements for Q220 magnets are performed by Toshibausing the harmonic coil method. The difference between the calculation and the measured data is 1.5%
for DM24 and 2% for Q220, which is sufficiently accurate when we determine maximum excitation currents. However, we should mention that sizable errors
exist in three-dimensional magnetic-field calculations.
The reason is as follows. A magnetic-field calculation
gives the deviation from the ideal magnet made of ironwith infinite permeability. For an ideal dipole magnet,

330

OL..o......................................""'-'-.o...J...."-'-'..........................I....J.............L................J..................Jo 20 40 60 80 100 120 140 160
current (A)Fig. 3. Field gradient By / x is plotted for Q220 magnets.
Measurements were performed for four magnets (106J09).

the magnetic flux density B is given by the equation
B = 1/ (J..-Lo x g). Here, I is total ampere turns, J..-Lo
is the permeability of air and 9 is the pole gap. In
the case of DM24, the present calculation predicts a
11.2% decrease of the magnetic flux density from theideal magnet. On the contrary, the measured data givea 12.6% decrease. The difference between the calculation and the measured data is more than 10%. The disagreement may be due to the following three reasons.
The first is that we neglected relatively less-important
structures in our calculations. The second is that the
adopted mesh size in the finite-element method is not
sufficiently small due to limitations of our computerresource. The last is that the BH curve used in the calculation differs slightly from the actual one. The comparison demonstrated here revealed the limitations ofrecent three-dimensional magnetic-field calculations.
References
1) O. Kamigaito et al.: Proc. 12th Symp. on Accelerator
Science and Technology, Wako , (1999) , p.233.
2) K. Hatanaka et al.: Proc. 11th Conf. on Cyclotrons andtheir Applications, Tokyo, (1987) , p.523.
3) M. Kumada et al.: Proc. 2nd Symp. on Accelerator Science and Technology, (1978) , p.73.

RIKEN Accel. Prog. Rep. 34 (2001)

Construction of the IRC for RIKEN RI Beam Factory
T. Mitsumoto,* A. Goto, M. Kase, J. Ohnishi, O. Kamigaito, N. Sakamoto, K .. lkegami, H. Okuno,
Y. Miyazawa, T. Hiasa,* Y. Kumata,* and Y. Yano
The intermediate ring cyclotron (IRC) is a roomtemperature ring cyclotron with four sectors that will
be utilized in the RIKEN RI-beam factory.1) It will
be installed as the intermediate stage between theexisting RIKEN Ring Cyclotron (RRC) and the superconducting ring cyclotron (SRC). The IRC , having a K value of 980 MeV, accelerates the extracted
beam from the RRC; the maximum acceleration energy
and the maximum magnetic rigidity of the IRC are
126.7MeV/nucleon and 4.57Tm, respectively. 2) The
main parameters of the IRC are listed in Table 1.
The construction of the IRC started in 1998. The
E-sector magnet was completed in April, 2000. All sector magnets were completed in December 2000. Figure 1 (a) shows a photo of the E-sector magnet. Figure 1 (b) shows a photo of the S- and W -sector magnets. Field measurement for the magnetic field of theE-sector magnet was performed. Details of the measurement are described in this report. 3 ) The field measurement for the other sector magnets will begin in
January 2001.
The main coil of the sector magnets consists of 11
pancakes of coils , which are divided into two parts.
These parts are excited independently by two power
supplies, the Ml power supply for 6 pancakes and theM2 power supply for 5 pancakes. The Ml power supply
with the maximum current of 450 Amperes is equippedwith a 3-Ampere bypass power supply in order to realize sufficient resolution for the excitation current.
The M2 power supply with the maximum current of
450 Amperes is equipped with four 15-Ampere bypass
power supplies which realize independent control of theexcitation currents of the four sector magnets.
The trim coils of the sector magnet consist of 20
pairs. The first three pairs and the last three pairsof each sector are excited by an independent power
Table 1. Main parameters of the IRe .
K-value
Number of sectors

Velocity gain factor
Number of cavities

(a)

(b)

Fig. 1. (a) E-sector magnet was completed at Niihama
works, Sumitomo Heavy Industries, Ltd. (b) S- andW -sector magnets. This photo was taken in September
2000.

Table 2. Specifications of 15 kW switching power supply
for trim coil.

980 MeV
4

Nominal input voltage

7

Maximum output power

15 kW

Injection

2.77m

Nominal output current

500 Amperes

Extraction

4.15 mHarmonics
Average radius

supply. The rest of the trim coils are connected inseries among sectors. The number of power supplies
for trim coils is 38. We adopted a switching type of
power supply for trim coils. The volume of the power
supply is almost 1/4 that of the dropper type. Table 2
shows the specifications of a 15 kW power supply for

Main

1.5
2

Flat-top
RF frequency (main resonator)
Cyclotron frequency

Sumitomo Heavy Industries, Ltd.

Nominal output voltage

400VAC

30V

Efficiency

90% typical

Cooling

Water cooled

Ripple and noise
18.0- 38.2 MHz

Stability

2.57-5.45 MHz

EMI
Size
Weight

50 mVp-p
Maximum output 10 ppm for 8 hours
Meets CISPR Pub. 22 Class A
486mm(W) 444rnm(H) 879rnm(D)120 kg331

the trim coils.
The first main resonator (ES-resonator) was assembled in November, 2000. Figure 2 shows a photo of
the resonator. A low-power test was performed. The
results of the test are described in this report. 4 )Manufacturing of all components of the IRe will becompleted in March 2001.
References

Fig. 2. The first resonator for the IRC. Flapping panels areshown.

332

1) Y. Yano et al.: Proc. 15th Int. Conf. on Cyclotrons andTheir Applications, Caen, France, (1998), p.696.
2) T. Mitsumoto et al. : RIKEN Accel. Prog. Rep. 33, 208(2000).
3) J. Ohnishi et al.: RIKEN Accel. Prog. Rep. 34, 333(2001).
4) N. Sakamoto et al.: RIKEN Accel. Prog. Rep. 34, 335(2001).

RIKEN Accel. Prog. Rep. 34 (2001)

Magnetic Field Measurement of the IRe Sector Magnets
J. Ohnishi, T. Mitsumoto,* A. Goto, and Y. Yano
The IRC sector magnets are under construction at
Sumitomo Heavy Industries, Ltd. and three of four sector magnets have been completed this year. We started
the magnetic field measurements of the first completed
E-sector magnet in order to verify the magnetic performance and to obtain the magnetic field data necessary
for the orbit calculations. This report describes themagnetic field measuring system and preliminary results.
Figure 1 shows a plan view of the field measuringapparatus. Eight Hall probes are placed on the Hall
assembly at intervals of 200 mm. The Hall assembly isdriven in the radial and the azimuthal directions withpneumatic pistons. This driving system was the sameas that developed for the magnetic field measurementof RRC. 1 ) The parameters of the driving are listed inTable 1. It takes longer than 3 sec for one driving time
because the friction of air flow is large in the tube
with a length of greater than 30 m. Figure 2 showsa block diagram of the control system. The signals
from a DO board on the computer control the electromagnetic valves which supply the driving pistons of
the Hall assembly with air. The positional accuracy of
the Hall probes was within about 1 mm, which was obtained from alignment error of the rails and the slackof the driving system.
The Hall probes (HHP-MU, AREPOC Ltd.) were
calibrated with an NMR gaussmeter in advance. Since
the temperature coefficients of the Hall probes were5- 7 x 10- 4 per degree, we measured the temperatureof the probes and corrected the output voltages by
the temperature coefficient of each probe. As a result
the measuring accuracy of magnetic fields was within
about 5 x 10- 4 . The output voltages of the Hall probes
and the temperature sensors (Pt resistor) were measured with a data acquisition unit (AT34970A) with a
GPIB interface.
Figure 3 shows a time chart of the excitation current
pattern. Settlement times when the deviation fromthe final magnetic field reaches 5 x 10- 5 are 2 and 4
hours for the maximum field strength (1.9 T) and low
field level « 1.4 T), respectively, which each include
1.3 hours of the initialisation. Reproducibility of themagnetic field was smaller than 1 x 10- 4 . Figure 4
shows the excitation curve of the IRC E-sector magnet.
The deviation from the calculation by TOSCA 2) was
Magnetic Field Measurement System

Hall Assembly(8 Hall probes)

Fig. 2. Block diagram of the control and measurement
system.

Fig. 1. Plan view of the IRe magnetic field measuringapparatus.

II

Max.
1. 01

Current

I

Table 1. Parameters for driving of the Hall assembly.
Range

Step

Time

R

730mm

IOmm. 20mm. 30mm

3.5 sec

Theta

180°

0.25°.0.50°.0.75°

3.8 sec

Sumitomo Heavy Industries, Ltd.

1. 00

0.99

I

o

I

I

I

I

30

60

90

Time(min. )Fig. 3. Time chart of the excitation current pattern.

333

Table 2. Difference between the measurement and the calculation by TaSCA. Bax indicates magnetic
field strength on the centreline of the sector magnet and Bave the average in the region of 90 degrees.
Bax(R=3500mm) [m TJ
Current

Measurement

100A

597

170A
240A

Bave(R=3500mm) [m T]
Measurement

Calculation

Measurement341

343(0.82%)

1.754

Calculation
1.739(-0.85%)1006

1009(0.29%)

573

580(1.21%)

1.755

1.739(-0.90%)

1397(0.41 %)

792

803(1.27%)

1.756

1.7 41(-0.85%)

290A

1392
1602

1596(-0.36%)910

913(0.36%)

1.760

1.748(-0.72%)

380A

1815

1802(-0.76%)

1026

1024(-0.17%)

1.769

1.759(-0.59%)

445A

1918

1904(-0.75%)

1080

1078(-0.22%)

1.776

1.766(-0.53%)

Excitation Curve
2.0 , - - --Kb=Bax/Bave

Calculation
597(-0.04%)

E-Sector 445.5A---,-----,----,-----,------,

1.5

SCD

1.0 1- ................,..... .

line: O.OIT
0.5 1- ... .. ... .. .. ..

Fig. 6. Contour plot of the magnetic field of the E-sector
magnet.
0.0 "---_ _--'-_ _ _--"-_

o100_ __'____ ----'-_ _ _- J

300

200

400

500

almost within 1%, as evident in Table 2.
Figure 5 shows the magnetic field distributions along
the pole centreline of the E-sector magnet. Figure 6
shows an example of a contour plot of the magnetic
field obtained from the mapping measurements. The
size of the mapping mesh was 10 mm and 0.25° in theradial and the azimuthal directions, respectively, inthe pole edge area where the magnetic fields change
rapidly. On the other hand, the mesh size was 20 mm
and 1.0° in other regions. It took 8.5 hours to measure
all of the points of 17196. The measuring time will
be improved to about 6 hours by using a digital voltmeter with better performance for the measurement of
the Hall voltages.
Next year we will measure the magnetic fields produced by trim coils and the interference with the next
sector magnet as well as the other sector magnets , andobtain the magnetic field data necessary for cyclotron
operation.

I (A)Fig. 4. Excitation curve of the E-sector magnet.

E-Sector
1.005

1.000

0.995

~
0.990
0
0

<.0
CV')

S 0.985
CD

"CD
0.980

-e-100A(0.6T)-v--- 170A (1. OT)- - 240A(1.4T)--*- 290A(1. 6T)- + - 380A (1 .8T)
- 0 - 445A (1. 9T)

0.975

O. 970 '-------'-~----'-------'------'---'

2500

3000

3600

4000

4500

R(rrm)

Fig. 5. Magnetic field distributions on the centreline of theE-sector magnet.

334

References
1) H. Takebe et al.: RIKEN Accel. Prog. Rep. 16 , 188(1982).
2) OPERA-3d/TaSCA, Vector Field, Ltd. , UK.

RIKEN Accel. Prog. Rep. 34 (2001)

Construction of the rf-Resonator for the RIKENIntermediate-Stage Ring Cyclotron
N. Sakamoto, O. Kamigaito, Y. Miyazawa, T. Mitsumoto, A. Goto, and Y. Yano
The four-sector intermediate-stage ring cyclotron(IRel») in the RIKEN RI-Beam Factory has two
single-gap-type accelerating resonators whose operational frequency range is 18.0- 40.5 MHz. 2) The resonant frequency is tuned by adjusting two flapping panels which are placed symmetrically to the median planeand finely tuned by block tuners (details are in Ref. 2).
The shapes of the resonators are optimized using thecomputer code MAFIA 3) so that the Q-values are aslarge as possible. The fabrication of one of the resonators is almost completed and low-power tests havebeen conducted (Fig. 1).
As shown in Fig. 2, the resonant frequency varies
from 17.8 to 41.3 MHz by changing the flapping panel
angle from 0° to 90°. The block tuner changes theresonant frequency more than 0.7% over the entire frequency range. The measured results are in good agreement with the MAFIA prediction (Table 1). The unloaded Q-values were obtained from measured loaded
Q and SWR. The Q-values were as large as 74- 79% of
the calculated values.
The higher modes appear at f > 80 MHz as shownin Fig. 3. These are well reproduced by a MAFIA
calculation; flux patterns of the magnetic field for eachmode are schematically illustrated in Fig. 4.
The vertically unbalanced rf field problem is one of
the most important issues for this resonator. Misalignment of the flapping panels and dee causes a vertical

Table 1. Measured (Estimated) resonant frequencies andQ-values at the panel angles of 0 deg. and 90 deg.

o deg.

Flapping panel
Frequency (MHz)

17.83(17.58)0.80(0.80)
21600(29300)(trimmer) 111/1 (%)

Q unloaded
Fig. 1. The IRe accelerating resonator. The side flange on
which the dee electrode is attached is removed.

90 deg.
41.34(40.74)0.80(0.80)
29500(37500)( ) values estimated using MAFIA code

45

40
,--,
N

::r::

::g

25000

::r::

£>

L.......J

c

:>,
()

~

~

20000 0"

30

~

p.

(J)

;::l
0"'
(J)

,--,
N

35

C1I

P.

25

6

:>,
()

~

(J)

;::l
0"'

60

...... ....
.....

(J)

~

~

15000
20

~

~

40

20

o

20

40

60

80

Flapping Panel angle [deg . ]Fig. 2. Measured resonant frequency and unloaded Qvalues.

o

20

40

60

80

Flapping- Panel angle [deg .]Fig. 3. Frequencies of the higher modes.

335

Basic

@)e

- 20

2nd

~ -30

.:s

........

c......
feeder

3rd

<.>

~

:::,..

~ -50
~

4th

I

...;:s... -40:::,..

I

Ie

--0

'r;;
.D

<

-60

-70
100

tliJ

Q)

Fig. 4. Schematic views of the magnetic flux pattern of thehigher harmonics.

.:s

50

~
;:s

...

<.>

~

:::,..

electric field at the median plane and the leakage ofthe rf field power into the vacuum chamber. In theworst case, elements such as the phase probe are damaged by the leaked rf power. To detect the verticalcomponent of the electric field at the median plane, abalance monitor (capacitive pickup) is installed in the
beam chamber outside the resonator. Using this monitor, the leakage can be minimized by offsetting one
flapping panel to the other. An example at 18 MHz
shown in Fig. 5 indicates that an offset angle of 0.2
degrees is needed to cancel the vertical field due to themisalignment of the dee.
We plan to measure the electric field distribution
using a perturbation method. The fabrication of the
No . 2 resonator is now in progress.
References
1) T. Mitsumoto et al.: Proc. 12th Symp. on Accelerator
Science and Technology, Wako, 1999-10, RIKEN (1999) ,

336

0

~

~

~

-50

t;D
~

<

- 100
0.6
-0 .2
0 .2
0.4
0 .0
Flapping-Panel(upper side) offset angle [deg.]

Fig. 5. Leakage field detection. The sign of the phasereflects the direction of the leakage field.

p.183.
2) N. Sakamoto et al.: Proc. 12th Symp. on Accelerator
Science and Technology, Wako, 1999-10, RIKEN (1999) ,p.224.
3) The MAFIA collaboration, User's Guide MAFIA Version 4.0, CST GmbH, LauteschagerstraBe 38, D-64289 ,Darmstadt, Germany.

RIKEN Accel. Prog. Rep. 34 (2001)

Status of the SRC for the RIKEN RI Beam Factory
A. Goto, H. Okuno, J. Ohnishi, T. Mitsumoto, N. Fukunishi, s. Fujishima, T. Tominaka, K. Ikegami,
N. Sakamoto, Y. Miyazawa, O. Kamigaito, T. Morikawa, M. Kase, and Y. Yano
We have made significant changes to the design ofthe sector magnet of the SRC (superconducting ring
cyclotron). The changes are as follows:(1) A pair of large active magnetic-shield coils has
been replaced with soft iron slabs that cover the valley
regions.
(2) The cold-pole scheme has been replaced with thewarm-pole scheme.
In the new design, the cyclotron is almost completely

covered with soft-iron slabs about 1 m in thickness, except in the central region. Some of these iron slabs arebridged on the top and bottom of the valley regions
between the sector magnets. The others of them areplaced vertically between these top and bottom slabs
so as to cover the space between the back yokes of
the neighboring sector magnets. The total weight ofthis falling-U-shaped iron-slab structure (referred to as
the "iron cover") is about 3,000 tons (the total weightfrom IRe
Magnetic shield (side)~ to Big RIPS
Fig. 1. Plan view of the newly designed SRC.

337

of the SRC amounts to 7,800 tons). The vertical outside slabs are assembled to form a double-leafed hinged
door to be opened when the maintenance is carried out
for the rf resonators, vacuum pumps, and so on in thevalley region.
The "iron cover" yields the following good results:(1) The SRC can be self-radiation-shielding.
(2) The stray field in the valley is reduced from
0.5 T to 0.1 T at maximum. The maximum sector field
needed to bend, for example, U 58 + 150 MeV /u is accordingly reduced from 4.3 T to 3.7 T because of thisreduction of negative stray field, with the K-value ofthe SRC being kept at 2,500 MeV. According to thislower flutter, we relocate the operating domain of thevertical betatron frequencies from the values between
1.0- 1.5 to those between 0.5- 1.0. The decrease of thevertical betatron frequencies causes an increase in thevertical beam size by a factor of about 1.4, but thispresents no problem because of sufficient acceptanceof the injection and extraction elements. This decrease
also makes the tolerances of the main and trim coils
and poles tighter, but they are still tolerable. According to the reduction of the maximum sector field,
the maximum magnetomotive force required is also
reduced from 5.4 MA/sector to about 3.8 MA/sector.
Now we adopt the solenoid windings of main coils of
22 layers times 18 turns (30 layers times 20 turns in theold design). The maximum stored energy and the electromagnetic forces exerted on the main coil are greatly
reduced from 390 MJ to 235 MJ and from 400 ton/m to
260 ton/m, respectively. This small stray field in thevalley allows us to use cryopumps, motors, control devices, and so on in a safe situation.

338(3) Superconducting magnetic channels for beam injection and extraction are not necessary. Now all the
injection and extraction magnetic channels inside thesector magnets are normal with the moderate power
consumption and their structures are very similar to
those for the RRC and the IRC.
(4) The shift of the injection and extraction trajectory depending on the negative stray field strength isgreatly reduced (almost no shift).
(5) The stray field outside the SRC is reduced: about
200 gauss at the maximum near the yoke and the vertical outside shield-wall. We need neither the active
magnetic shielding which is difficult to fabricate nor
the thick iron plates enclosing the huge SRC vault. We
place the rf oscillators near the SRC like they are for
the RRC and the IRC. The SRC vault is now very safefor those working at the site even inside the cyclotron.
For the warm-pole scheme, details are given elsewhere in Ref. 1.
We have decided not to conduct tests of the prototype sector magnet. We learnt many important thingsfrom this prototype that has accomplished its mission.
The new design of the sector magnet has almost been
finalized. Winding of the main coil is scheduled to startaround May 2001. Design of the other components
such as the injection and extraction magnetic channels
and an rf resonator is currently in progress.
The layout of the newly designed SRC is shown in
Fig. 1.
References
1) H . Okuno et al.: RIKEN Accel. Prog. Rep. 34, 339(2001).

RIKEN Accel. Prog. Rep. 34 (2001)

Design of Sector Magnets for Superconduct.ing Ring Cyclotron
H. Okuno, T. Mitsumoto,*l N. Fukunishi, J. Ohnishi, S. Fujishima,*2 T. Tominaka,*3
K. Ikegami, Y. Miyazawa, A. Goto, and Y. Yano
Significant changes have been made to the sector
magnets of the superconducting ring cyclotron (SRC),
as mentioned in Refs. 1 and 2. Here, the new design
will be reported briefly, focusing on the changed parts.
Figure 1 shows a cross-sectional view and a planview of the sector magnet and its basic parameters arelisted in Table 1. The main components of the magnet
are its superconducting and normal-conducting coils,
a cryostat which consists of 80-K thermal shields andvacuum vessels, poles and a yoke. Two types of superconducting coils are used: a pair of main coils and agroup of trim coils. Both coils are located on the upperand lower sides with respect to the midplane. A groupof normal-conducting trim coils for fine magnetic-fieldcorrection is also arranged on the upper and lower sidesof the beam chamber. The cold mass is supported bythree types of thermal insulating support (i.e., Fr, Fq,
Fz support) from the cryostat wall at room temperature.
In the new design we adopted a warm-pole arrangement, as shown in Fig. 2. The main coil vessel, composed of 50-mm-thick stainless-steel plates, is of aroundish trapezoidal shape. This vessel surrounds theupper iron pole at room temperature. The width of

the gap between the 4.5-K vessel and the 300-Kiron
pole is designed to be more than 110 mm, enough toincorporate an 80-K thermal radiation shield. A pairof approximately I-m-wide and 20-mm-thick stainlesssteel plates link the inner corners of both long-section
sides of the coil vessel, as shown in Fig. 1. The plate in
the upper corners crosses through the rectangular hole(1.2 m wide and more than 100 mm high) of the warm
iron pole. This hole helps to form isochronous fields.
Although the mechanical stiffness of this structure decreases compared with that of the cold pole structure,
it is still rigid enough to support the electromagnetic
forces because the magnetic forces decrease due tothe reduction of the total magnetic motive forces, asmentioned in Ref. 2. By adopting the warm pole arrangement we can avoid the problem that soft iron,which has the property of brittleness in the ultralowtemperature region, is used as material for the main
support structure against huge magnetic fields as it

Table 1. Main parameters of the sector magnets.
Average radii of beam injection
extraction
Sector angle of main coil
Maximum magnetic fieldin the beam orbital areain the main coilin the trim coil
Main-roil's ampere turns per magnets
Magnetic stored energy for six magnets
Maximum operation currents-for main coil-for trim coil

3.56m
5.36m
25 degrees
3.8T
4.5T
5.1 T
3.96MA
240MJ
5<XX}A3(0) A
8500 ton

Main CoiMP

Fig. 1. A cross-sectional view and a plan view of the sector
magnet.
*1*2*3

Sumitomo Heavy Industries, Ltd.
Ishikawajima-Harima Heavy Industries Co., Ltd.
Hitachi, Ltd.

Fig. 2. Warm-pole arrangement.

339

Table 2. Main specifications of the superconducting coils
for the sector magnets.
unit

Property

Main Coil

S. C. Trim Coil

7.5
6
200

7
4setx6

Solenoid
396

Double pancake

Overall size:
Size m2
Number pairs
Weight ton

9

Coils:
WmdingTurns/coilNominal cwrent
Overall cwrent
densityStored energy
Peak field
Cooling method5(0)A
Almm2 33.3

MJ

T

16/50128/32
3<xx)

25

235
4.5
Bath cooling2
5.1
Two-phase forced
flow cooling

8x 15
AI stabilizedNbTi
cable
18.5:0.84: 1
14970@5 T, 4.5 K

8x 15
AI stabilized NbTI
cable
18.5:0.84: 1
14970@5T,4.5 K-

Conductor:
Size mm2
Structure
Ratio Al:Cu:NbTi
Critical current A
Stabilized current A> 6<mAhas been for more than thirty years in the cold polearrangement.
Table 2 summarizes the specifications of the superconducting coils for the sector magnet. The solenoid
winding of 22 layers times 18 turns using superconducting wire of 8 mm x 15 mm (30 layers times 20 turns
in the old design) was adopted for the main coil. We
apply a cryogenic stabilizing method for the main coilto prevent the coil from quenching. The gaps between

340

turns and between layers of the main coils were designed to be 0.8 mm and 1.5 mm in distance, respectively. These gaps are held with numerous glass-fiberreinforced plates. Flat plates are adopted for the insulation between turns in order to increase the reliabilityof electric insulation.
In the old design of the trim coils, solenoid windings
using superconducting wire of 2.9 mm x 3.6 mm in size
were bath-cooled in He vessels and the cryogenic stabilizing method was applied. However, we have been
bothered by the problem that the evacuation of He
bubbles, which is important to keep the coils superconducting during bath cooling, is very difficult in thetrim coils because they are flat and thin and available
spaces in the vertical direction are narrow. In orderto solve this problem we decided to adopt the doublepancake windings that are indirectly cooled by forced
two-phase helium through a system of tubes attachedto the coil casing. The same conductor as that of themain coil will be used for easier winding. The coil isnonstabilized but there are many successful cases using
such types of superconducting coils. The design of thedetails of the superconducting trim coil is currently inprogress and is being undertaken carefully to realize
the required performances.
References
1) Y. Yano et al.:

RIKEN Accel. Prog. Rep. 34, 301(2001).

2) A. Goto et al.: RIKEN Accel. Prog. Rep. 34, 337(2001).

RI KEN Accel. Prog. Rep. 34 (2001)

Design of the Injection and Extraction Systems for the
RIKEN Superconducting Ring Cyclotron
S. Fujishima,* H. Okuno, A. Goto, and Y. Yano
Along with the change of the design of the sector magnets of the RIKEN Superconducting Ring Cyclotron (SRC), the design of the injection and extraction systems for the SRC has also been changed significantly compared to the previous design last year. 1 )The basic layouts and specifications of the injectionand extraction elements were determined by numericalanalysis of the injection and extraction trajectories. In
the analysis, much care was taken in particular to minimize not only the required fields of the elements but
also the differences between various beam trajectories
in the elements.
The stray field from the sector magnets depends
non-linearly on the magnetic rigidities of the beams,
and causes the difference between various beam trajectories in the elements. Larger differences in the trajectories require a wider bore of the element.
In the previous design of the SRC, stray field fromthe sector magnets had increased to -0.6 T at the maximum and had caused large differences in the trajectories. But, in the present design, stray field from thesector magnets decreased to about -0.06 T because of
the iron yoke covering the SRC, so that the differencesin the trajectories also decreased.
However, the injection and extraction elements
should be installed in a small space limited by thevacuum chamber for the beams or thermal insulating
vacuum vessels of the sector magnets, and moreover,should generate sufficiently high fields to bend a beam
which has a high magnetic or electric rigidity.
Because of these difficulties, it remains a challenge
to design the injection and extraction systems.
Table 1 shows the energies and magnetic rigidities of three typical beams. The beam of 238U78+(100 MeV lu) has the lowest magnetic rigidity. The
beam of 238U88+ (350 MeV lu) has the highest magnet rigidity at extraction. The beam of 238U49+(100 MeV lu) has the highest magnetic rigidity at injection. The beam of 238U88+ (350 MeV lu) also has

Table 1. Energies and magnetic rigidities of typical beams.

U 78+
U 88+
238 U 49+
238
238

Energy [Me V/0]
Inj.
Ext.

Inj.

Ext.

40.4
115.2
40.4

2.82
4.31
4.49

4.51
7.94
7.1 8

100
350
100

B p [Tm]

Ishikawajima-Harima Heavy Industries Co. , Ltd.

the highest electric rigidity.
In the first stage of the analysis, magnetic fieldsof the sector magnets were calculated with a threedimensional computer code, "TOSCA." However, thedesign of the normal-conducting trim coils of the sector
magnets has not been optimized perfectly, thus the calculated fields of the sector magnets include about 0.3%
error. This causes shifts of the injection and extraction trajectories. To compensate them, the energies of
the injection or extraction beams were slightly changed
as the length of the first or the last equilibrium orbit
become equal to the design value, respectively. And
then, to trace the beam trajectories, the equation of
motion was solved with using the Runge-Kutta-Gill
method. In the calculation, the electric or magnetic
field of each element was superimposed on the field of
the sector magnets.
Figure 1 shows a schematic layout of the injectionand extraction elements, and shows the trajectoriesof two typical beams of 238U78+ (100 MeV lu) and
238U88+ (350 MeV lu). Because of the suppression of
the stray field in the valley, the difference between two
trajectories is indiscernibly small in the figure. Thislayout has not been optimized completely, so it may
need to be partly modified.
The injection system consists of one superconducting bending magnet (SBM) , two normal-conducting
magnetic inflection channels (MIC1 and MIC2), andone electrostatic inflection channel (EIC). The extraction system consists of one electrostatic deflection
channel (EDC), three normal-conducting magnetic deflection channels (MDC1, MDC2 and MDC3) , and one
normal-conducting bending magnet (EBM).
In the previous design, the extraction system did
not include the MDC1 , and the EDC required a considerably high field of -105 k V I cm. To suppress therequired field of the EDC, the MDC1 was added tothe system and supplemented the bending power ofthe EDC.
Because the injection beam will be introduced crossing the ErC and EDC , their respective electrodes haveholes to pass the beam. To minimize the hole diameter, each trajectory is adjusted with several steering
magnets to cross at the same point on the respective
electrodes of the EIC and EDC.
All magentic channels are installed in the gap between upper and lower coils of the sector magnets.
Table 2 shows the specifications of the injection andextraction elements.
Each magnetic element consists of main dipole coils
and compensation coils to suppress the fringe field on341

Fig. 1. Schematic layout of the elements and trajectories of typical beams.
Table 2. Specifications of the injection and extraction elements.
Radius
[em]
EIC
MIC1
MIC2
SBM
EDC
MDC1
MDC2
MDC3
EBM

342

Angle
[deg.]

Length[em]

BorE (max.)[T],[kV/em]

130.0
119.7
154.2
170.5

90
0.285 (Normal)
0.969 (Normal)
3.794 (Super)

-

-

140.0
122.0
120.6

49.0
72.4
81.0

-

-

220.0
232.0
260.0
368.0

13.0
37.0
39.6
54.2

228.0
49.9
149.8
179.7
348.1

-90
- 0.060 (Normal)- 0.200 (Normal)- 0.540 (Normal)- 2.102 (Normal)

the first or the last equilibrium orbit.
To reduct fabrication cost , and to improve feasibility, all magnetic channels were specified as normalconducting magnets.
The length of each element was determined taking
into consideration the balance between the differenceof the trajectories in the element and the required fieldof the element.
References
1) S. Fujishima et al.: RIKEN Accel. Prog. Rep. 33, 218(2000).

RIKEN Accel. Prog. Rep. 34 (2001)

Design of Superconducting Bending Magnet forSuperconducting Ring Cyclotron
H. Okuno, S. Fujishima,*! T. Tominaka,*2 K. Ikegami, J. Ohnishi, A. Goto, and Y. Yano
The significant point in the new design of the superconducting ring cyclotron (SRC) is that iron plates ofabout 1 m thickness cover the valley regions for additional magnetic and radiation shielding. They suppress
the leakage field from the sector magnets, decreasing magnetic motive forces for the maximum bending
power, which makes the critical parts of the SRC easier to design and produce. A superconducting bending
magnet (SBM) for beam injection, which is one of the
key elements in the SRC, can also benefit from the additional shield. An iron return yoke can be used for
the SBM, while in the previous design, the iron placedin the center region did not work due to saturation
without the iron cover. An iron-shielded magnet does
not need such a large magnetic motive force and has asimple coil structure compared to an iron-free magnet
with an active-shield coil proposed previously.!) In thefollowing, the design and R&D work of the SBM aredescribed.
The main parameters of the SBM are listed in Table 1. The SBM needs to generate a magnetic field of
about 4 T along the beam trajectory with a curvatureof about 1.2 m. Figure 1 shows the proposed cross section and a plane view of the SBM. The two coils, theiron poles and the yokes generate the required fields.
Flat coils are adopted since they can be wound andsupported easily. The iron pole is used for the mandrel
in the coil winding. The yoke is divided into two parts:
the cold yoke and warm yoke. The cross section of thecold yoke, through which about half of the flux passes,
is bilaterally symmetric. This configuration decreases
sifting forces and unbalanced forces on the cold mass,
while the weight of the cold mass is not as large (about
3 tons). The C-shape of the warm yoke is adopted be-cause the available space for the warm yoke at the sideof the sector magnet is very narrow, as shown in Fig. 1of Ref. 2. A warm duct is installed for the ion beams.
Iron shims and water-cooled baffle slits are attached tothe duct.
Test coils were fabricated and tested for the designof the real SBM. The main parameters are listed inTable 2. Two types of coil structure were tested: onehas vertical channels at every second layer (Coil A)
and the other has no vertical channels (Coil B). Theirwinding method and support structure were designed
to be as close as possible to those of the real SBM. The
test coil was tested in a field of about 4 T generated
with a bias split coil in order to simulate the real operation. Figure 2 shows a photograph of the test coilwith the bias coil. Figure 3 shows the results of theexcitations of the two coils under real SBM operating
conditions. They were tested under the base field of 0 T
or 4 T. The results for Coil B are very promising since
the quenches occurred at a more severe condition thanthat of the SBM. Transversal quench propagation velocities were obtained from measurements of voltages
between the taps placed at every fifth layer for the twocoils. These results show that the normal zones in CoilB propagate in a layer direction more than three times

Table 1. Main parameters of the SBM.

Fig. 1. (a) Plane view of SBM and (b) cross-sectional viewof the inside of the cryostat.

Item
Type
Required field
Maximwn field in the coilStored energy
Homogeneity
Beam bore
Radius
Angle
Coil size
*1

*2

Value
Flat coil, Iron pole
Iron yoke (cold and wann)
4.0T
4.5T
0.56MJ
2-3 x 10-3
40 (H) x 30 (V) nun2
1208.4 nun (R. T.)
75.72 degree
55 x58 nun2

Ishikawajima-Harima Heavy Industries Co., Ltd.
Hitachi, Ltd.

Table 2. Main parameters of the test coils.

Item
Curvatme [nun]Angle [deg.]
Width of the inner
mandrel [nun]Width and height ofthe coil [nun2]
Total tum
He channel(vertical channel)

CoilA
960
68
52

CoilB
96)

68
52
23.4 x
22.5
233
2 No

23.3 x 22.5
197
Each
layer

SBM
1208
76
142
58x
55
1317
Each
layer

20

343

2500
•

2000

Coil Bg 1500
C

~
~

()

1000
500

,
'\

0
0

2

4

6

8

10

Field in the coil (T)Fig. 3. Quench history. White squares and black circles indicate the points where the quench of Coil A and Coil B
occurred, respectively. Lines which start from 0 T (4 T)
at zero current indicate excitation curves in the case of
the bias-off (bias-on). Currents in parentheses indicatethat the excitation terminated for reasons other thanquench.
Fig. 2. Assembled test coil.

March 2001.
faster than in Coil A, which means that Coil B is safer
than Coil A when quenches occur. From these results,
the coil structure of the SBM was designed based onthat of Coil B.
The fabrication of the SBM will be completed by

344

References
1) H. Okuno et al.: RIKEN Accel. Prog. Rep. 33, 220(2000) .
2) A. Goto et al.: RIKEN Accel. Prog. Rep. 34, 337 (2001).

RIKEN Accel. Prog. Rep . 34 (2001)

Measurement of Outgassing Rates of Materials Used in the Vacuum
Chamber for RIKEN Superconducting Ring Cyclotron andIntermediate Ring Cyclotron
K. Sugii, K. Ikegami, A. Goto, and Y. Yano
The vacuum chamber of the RIKEN superconducting ring cyclotron (SRC) and the intermediate ring
cyclotron (IRC) which is under construction in the
RIKEN RI-Beam Factory Project uses various materials such as stainless steel (SUS), elastomer O-rings
and a super insulator. For evaluation of the gas load
due to outgassing from these materials and corresponding pumping requirements, measurements of the outgassing rates are indispensable.
A schematic diagram of the experimental setup forthe measurement of outgassing rates is shown in Fig. 1.
A vacuum chamber is composed of an upper dome anda lower dome. A fiat plate having a central circularorifice is mounted between the upper dome and thelower dome. The orifice is 10 mm in diameter, and its
conductance is 9.2 x 10- 3 m 3 /s for N 2 • The chamber
and the fiat plate are made of stainless steel (SUS304),
and are prepared by electropolishing. A sample formeasurement of the outgassing rate is placed into theupper dome. In the case of the measurement of an 0ring sample which is used for sealing, the O-ring was
set in a groove (see Fig. 1). Gas fiow rate through theorifice (Q) is given by the following equation,

Q = C x (PI - P2),
where PI and P2 are the pressures of the upper dome
and the lower dome, respectively, and C is the conduc-tance of the orifice. When amounts of outgassing for
the upper dome including a sample (Qt) and the upper dome without a sample (Qc) are measured respectively by the above equation, an amount of outgassing
for only the sample (Qs) is calculated fromQs = Qt - Qc.
In order to reduce the Qc as background and prepare
the initial surface state, the chamber was baked at
150°C for about 24 hours , and was then exposed toair. The Qc was measured after these operations. Figure 2 shows amounts of outgassing which were measured for two elastomer O-rings at room temperature.
The two types of O-rings are the following: (1) general
fiuoroelastomer and (2) high-quality fiuoroelastomer:
FLID ARMOR (NIPPON VALQUA INDUSTRIES,
LTD). The size and surface area of each O-ring are
ID139.1 x OD153.0 x ¢ 6.98 mm and 1.0 x 10- 2 m 2 ,respectively. The results are shown as follows: (1)for the general fiuoroelastomer when the entire O-ring
surface was exposed to ultra-high vacuum (Qga), (2)for the general fiuoroelastomer when an O-ring sample was used for vacuum sealing (Qgs), (3) for FLID
ARMOR when the whole of O-ring surface was exposed
to ultra-high vacuum (Qfa), and (4) for FLID ARMOR
when an O-ring sample was used for vacuum sealing

Upper dome

L-. L. . L. .J.- -L-. L. .Lt.Ll~!.Il.lII~J. L-.~

10.7
10-'

10°

10'

10 2

Time (h)Fig. 1. Experimental setup for measurement of outgassing
rate.

Fig. 2. Measurement results of amounts of outgassing for
unbaked fiuoroelastomer O-rings.

345

( Qfs). Outgassing rates of the general fl uoroelastomer
and FLID ARMOR after pumping for 100 hours were
1.5 x 10- 4 Pam 3/s/m 2 and 8.7 x 10- 5 Pam 3/s/m 2, respectively. From making comparisons at each point
between the Qga and the Qfa or the Qgs and theQfs, we found that the outgassing rate for FLID ARMOR was 56- 78% of the value of the general fluoroelastomer. The difference between the O-rings was not
significant. The treatment and preservation of O-rings
appears to be more important than the choice material for them. Then, from making comparisons at eachpoint, between the Qga and the Qgs, we found that
the Qgs was 25- 40% of the Qga. (In the case of FLID
ARMOR, the Qfs was 20- 40% of the Qfa.) Therefore,
it is considered that 20- 40% of the O-ring surface is exposed to vacuum when the O-ring is set into a groove
for vacuum sealing. We consider that these results will
be helpful in estimating the amount of outgassing in
vacuum systems that use elastomers, such as the SRC
or the IRC.
A super insulator which is used as a covering aroundshields at 80 K for superconducting coils for sector
magnets cooled at 4.5 K is used to reduce radiation loss
from the wall of the vacuum chamber of the cryostat.
Figure 3 shows outgassing rates of the super insulator(SI-1) with time after the start of pumping. The super
insulator (SI-1) is multilayerinsulation and is made ofaluminum vaporized polyester sheets. SI-2 values areshown in the graph comparison with the measurement
values for SI-1. SI-2 is made of commercially avail-

346

10-9

----j---i-- - . 11

10°

10

i I Ii f1

10

. .

2

10

3

Time (h)Fig. 3. Measurement result of outgassing rates for super
insulators.
able polyester and its outgassing rate was measured
by the National Institute for Fusion Science (NIFS)'
group (Akaishi et al.). 1) The outgassing rate of SI-1 is
2 x 10- 5 Pam 3 Is/m 2 after 10 hours, and of the order of
rv10-7Pam3/s/m2 after 400 hours and is higher thana factor of 3 of that of SI-2.
These measurement results will be reflected in thedesign of the pumping system for the vacuum chambersof the SRC and the IRC.
References
1) K. Akaishi et al.: J. Vac. Soc. Japan 37, 56 (1994).

RIKEN Accel. Prog. Rep. 34 (2001)

Helium Cooling System of the RIKEN Superconducting
Ring Cyclotron
K. Ikegami, T. Kawaguchi, H. Okuno, M. Ohtake, J. Ohnishi, A. Goto, and Y. Yano
the twelve main coils are installed in the liquid helium
vessel of the control dewar. The total helium mass flowof seven current leads is estimated to be 391/h. Fifteen
current leads (five pcs of 4 kA and ten pcs of 300 A)
of twelve sets of trim coils are also installed in the liquid helium vessel of the control dewar. In this case,the total helium mass flow of fifteen current leads isestimated to be 711/h. The superconducting conductors of the coils are electrically connected to the power
leads in the liquid helium vessel of the control dewar.
The thermal shields of the cryostats are cooled down
to 50 K- 60 K by gas helium supplied from the refrigerator. The required capacity of thermal shields is 2900 W
at 60 K. Twelve sets of main coils are cooled down to
4.5 K by liquid helium from the refrigerator. Twelve
control valves are installed in the control dewar to control the flow of liquid helium. The flow will be adjusted
to minimize the temperature difference between eachcoil. The required capacity of main coils is 353 W at
4.5 K. Twelve sets of trim coils are cooled down to
4.5 K by the two-phase forced cooling method. The
helium flow is adjusted similarly using twelve control
valves. The required capacity of trim coils is 52 W at

The design of the superconducting ring cyclotron(SRC) having a K-value of 2500 MeV, which is to bebuilt in the RIKEN RI-Beam Factory project, was significantly changed at the beginning of December 1999.
Instead of using the superconducting active shield coilsof Helmholtz coil type, iron magnetic shields l ) are used
for the valley regions of the SRC to reduce the large
leakage flux from the six sector magnets. The designof the superconducting main coils and superconducting trim coils of the sector magnet which are set ina single cryostat, was changed as well. The design ofthe injection system 2 ) for the SRC was also changed.
Only one bending magnet in the injection system will
be superconducting.
Figure 1 shows the entire flow of the helium cooling system for the SRC. The cooling system will be aclosed-circuit system without liquid nitrogen. It consists of the six cryostats of the sector magnets , thecryostat of the bending magnet in the injection system, a control dewar, a refrigerator, three compressors
and five buffer tanks. A control dewar will be locatedon the top of the six sector magnets. Seven current
leads (2 pieces (pcs) of 5 kA and 5 pcs of 100 A) forfrom SBM

Emergency bypass line~from SBM.:==l

Rupture disk
Relief valve
Con ro dewar.~~Charge valv
I 11 11II

1I I I 11

Heat exchange

-

...

.

cv

CV

CV

'"

'"
'"

-

:: :1[1:: :111 :

11

11

II

..

.. "

1111

" II

1111

:: :: ~:: :: ~::::11 :::::11

II

..

co~

11rH±±=1-fI-+j1 ....

3:p=~.

H.

=P 3
~Ml

~~3MPa=Main coil Ie ~ds

im

SM2

SM3

SM4

SM5

SM6

He refrigerator

SBM
Fig. 1. The helium cooling system for the SRC with a bending magnet.

347

Table 1. Required capacities of the sector magnets and thebending magnet for the injection system.
Capacity

Sector magnets
Main coils

Coils at 4.5 K

353 W

Thermal shield

2900W

Current leads

39 D/h

Bending magnet

Capacity

Refrigerator

Coils at 4.5 K

445 x 1.3 <600 W

Trim coils
52 W

40W

Thermal shield

3500W

56W

Current leads

120 Il Ih

71 D/h

1.7 D Ih

4.5K.
The coil of the superconducting bending magnet iscooled down to 4.5 K through transfer lines connectedto the control dewar. A control valve is installed in
the control dewar to adjust the helium flow. The totalrequired capacity is 40 W at 4.5 K: 5 W from radiation
loss of the wall, 10 W from loss of transfer lines, and
25 W from heat deposit by neutron radiation. The
thermal shield loss is 56 W at 60 K. The total helium
mass flow for the current leads of the magnet is 1.7l/h.
All required capacities of the SRC are listed in Table 1.

348

Table 2. Capacities of the refrigerator for the SRC.

The refrigerator has a capacity of 600 W (445 W multiplied by a safety factor of 1.3) at 4.5 K for the coils,
3500 W at 60 K for thermal shields, and 120 l/h for current leads, as listed in Table 2. The total refrigeration
capacity at 4.5 K is approximately 1.5 kW.
References
1) Y. Yano et al.: RIKEN Accel. Prog. Rep. 34, 301(2001).
2) H. Okuno et al.: RIKEN Accel. Prog. Rep. 34, 339(2001).

RIKEN Accel. Prog. Rep. 34 (2001)

New Liquid Helium Supply and Recovery System
K. Ikegami, M. Ohtake, and Y. Yano
The refrigerator having a maximum capacity of
501jh was installed in the RIKEN main building located in the center of RIKEN before ten years ago andis operated to supply liquid helium for the researchers.
With year, the refrigerator often was broken down, andhad to be repaired it. It's capacity gradually became
lower 40 ljh on an average. On the contrary, as researchers using a liquid helium increased with year,
it was difficult to supply liquid helium of more than
300001 per a year by using this old refrigerator to them.
A new liquid helium supply and recover system tosupply liquid helium for RIKEN's whole researchers
was renovated at the last year. The building for thesystem is completed at the end of November in thisyear. The system will be installed in the building after
completing at the end of next March. Operation of thesystem will be started at the beginning of next April.
The system has the maximum capacity of 200 ljh tosupply liquid helium consists of pure gas helium cadres,a buffer tank of 15 m 3 , a valve stand, a compressor of
355 kW, an oil remover, a liquid nitrogen tank of 11 m 3 ,an refrigerator of a type of TCF-50 made by LINDE, aliquid helium vessel of 7 m 3 , impure gas cadres, a gas
dryer and purification device, and a recovery system
as shown in Fig. 1. Gas helium from pure gas cadres is
introduced to the compressor, compressed, introduced
to the refrigerator, and liquefied. Liquid helium madeby the refrigerator is saved in the helium vessel andwill be supplied to the researchers.

Gas Recovery Pipelines(To Each Area)-...c..a-----'

Fig. 1. A block diagram of the liquid helium supply andrecovery system.

Table 1. The liquid helium supply and recovery system.
Ncrne
Refrigerator

Capacity em size
200 aJhat 4.5 K

Type em pressure
TCF-50Circulation compressor

355 KW

1.7 MPa

Gas cadre (pure)

630 rri

14.7 MPa

Gas cadre (impure)1800 rri14.7 MPa

Liquid nitrogen tank

11 rri0.93 MPa

Buffer tank

15 rri0.93 MPa

Gas dryer

130 Nrri/h

14.7MPa

Liquid helium vessel

7rri

Recovery gas I:aJ

120 rri

50 rrmAq

Recovery compressor

130 Nrri/h

14.7 MPa

Recovery gas holder

20 rri

50 nmAq

Recovery blower

80 Nrri/h

50 nmAq

0.2013 MPa

The recovery system consists of a recovery compressor of 130 Nm 3 jh, a gas bag of 100 m 3 , and three recovery stations whose each station has one gas holder of
20 m 3 and one blower. One recovery station is placednear the new building located in south side of RIKEN.
The second recovery station connected to the systemthrough a recovery pipe of length of 500 m, is put in
RIKEN main building. The third recovery station connected to the second recovery station through a recovery pipe of length of 400 m is put in behind of the east
brain building located in east side RIKEN. The RARF
(RIKEN accelerator facility) is connected to the third
staion through a recovery pipe whose length of 150 m.
The recovered gas from each station is saved in the gas
bag first. After compressing saved gases to 15 MPa by
the recovery compressor, one part of the gas is saved
in impure gas cadres through a dryer. Another partof compressed gas after passing dryer, is purified , introduced to the refrigerator and liquefied again. Eachcapacity of the system is listed in Table 1.
The system and all recovery stations can be operated
automatically from the controller using the computer
installed the system side.
This system will be used to test as a superconducting bending magnet for the superconducting ring cyclotron (SRC) and the superconducting triplet quadruple magnet for the big projectile fragment separator(BIGRIPS).

349

RIKEN Accel. Prog. Rep. 34 (2001)

Prototype of Superferric Quadrupole Magnets
for the BigRIPS Separator (I)
H. Kouzu,*l T. Kubo, T. Tominaka,*2 K. Kusaka, M. Okamura, Y. Yano,
O. Ohsaki,*l T. Tsuchihashi,*l and T. Hirumachi*l
In the RIKEN RI-beam factory project, radioactive
isotope (RI) beams are to be produced using projectile fragment separators called BigRIPS. Superferricquadrupole magnets (iron-dominated superconducting
quadrupole) are to be used for the BigRIPS separatorsin order to efficiently produce RI beams. A prototype
consisting of a superferric quadrupole triplet has been
fabricated for R&D studies on the basis of the design
reported in Refs. 1 and 2. In this report, we outline
the prototype and describe the results of testing.
The prototype quadrupole triplet is installed in asingle cryostat. Cross-sectional views are shown in
Figs. 1 and 2. The iron yokes and superconducting
coils installed in a helium vessel are cooled by theliquid-He bath cooling method. The three quadrupoles
are connected rigidly to each other by stainless steel
bars. The helium vessel is supported from the vacuum vessel of the cryostat by six axial and eight radial
supports that are made of glass-fiber-reinforced plastic (GFRP) or carbon-fiber-reinforced plastic (CFRP).
The lengths of the radial supports can be adjusted fromthe outside of the vacuum vessel in order to align thequadrupoles with respect to the beam axis. An 80 K
shield with a cooling pipe surrounds the helium vessel,
and is cooled with liquid-N 2 . The 80 K shield is sup-ported from the vacuum vessel and the helium vessel.
Three quadrupoles have an identical cross section.
Their pole-tip radius and warm bore radius are 170 mm
and 140 mm, respectively.
The nominal effective
lengths of the quadrupoles are 500 (Q500), 800 (Q800),
and 500 (Q500) cm, respectively. The maximum poletip fields are 2.4 T , corresponding to the field gradientof 14.1 Tim. The main parameters of the quadrupoles

He vessel801( shield

*1

350

Toshiba Corporation
Hitachi Ltd.

Vacwn vessel
SOK shIeld

He vessel
Vacu.n vessel

Fig. 2. Cross-sectional view perpendicular to the beamaxis.

Fig. l. Cross-sectional view parallel to the beam axis.

*2/

Table 1. Main parameters of the quadrupoles.
Effective magnetic length (m)Pole tip radius (mm)Warm clear bore radius (mm)Field gradient (T/m)
Winding of coil
Nominal current per pole (kA)
Nominal current (A)Nominal turn number
Nominal current density (Nmm:!)
Cross section of coil (mm:!)
Straight length of coil (mm)Total length of coil (mm)Length of iron (mm)Outer radius of yoke (mm)Q500(* 1)

Q800(*2)

~0.54

~0.84

170
140
14.1

170
140
14.1

orderlyorderlv

199
142
1403

190
13G
140a
110
17:30
740
940
740
480

115

17:30
440
G40
440
480

(*1) The quadrupole whose design effective length is
500cm.
(*2) The quadrupole whose design effective length is
800cm.

Fig. 3. Schematic view of the superconducting coil.
Table 2. Main parameters of the superconducting wire.
Insulated diameter(mm)Bore diameter(mm)eu/super ratio
RRR ofCu
Filament diameter('1 m)

1.15
1.10
G.G
100-10575

are listed in Table 1.
The superconducting quadrupole coils are of the
racetrack type which was described in our previous
reports. 1 ,2) This type allows ordered coil winding. A
cross-sectional view and a schematic view of the coil
are shown in Figs. 2 and 3, respectively. We used a
NbTi superconducting wire whose specifications are
summarized in Table 2. The specifications are determined based on the quench protection analysis described in Refs. 1 and 2. Each coil that consists of 53
layers was wound orderly on a mandrel by wet winding
method. Epoxy was applied to the coils layer-by-Iayer
during the winding. The epoxy contains fillers so thatIii·-r-·-·-·-·-·-·-·- ·I·---·---·---·--'-·· .

\
"
\

i
i
i

!

I

\

/

/

i . ·. .

i

..

i

Yoke

Screw

Kapton foil and G 10 sheet

Fig. 4. Coil support.
its thermal contraction rate is similar to that of the superconducting wire. During the winding, the coil waspressurized twice by a plate and the glass tapes thatwere impregnated with the resin were inserted several
times in order to adjust the coil height. The coils were
cured at 100 0 e in an oven after the winding. The design values of the coil height and the coil width are
55.8 mm and 35.8 mm, respectively. Twelve coils inall were wound for the quadrupole triplet (4 coils x 3
quadrupoles). We measured the size of all the coils.
The coil height deviation was 0.5 mm except for the
first coil, which was 0.9 mm. The width deviation wasmeasured to be within 0.5 mm. Magnetic field calculations reveal that the deviations are within allowablevalues.
The coils are supported by the iron yoke, as shownin Fig. 4. A stainless steel bar which we call a 'wshaped' support is used to support the coils againstelectromagnetic force. This w-shaped support is placed
between the yoke and the coils, being continuous forthe length of the yoke. The coils are pushed against
the w-shaped support by tightening screws, as shownin Fig. 4. The shimming arrangement is also shown in
Fig. 4. The shim between the coil and the w-shaped
support is a wedge shaped stainless steel piece, which
provides a self-tightening effect when the coils shrink
due to cooling. The Kapton foil and the G 10 sheet
provide electrical insulation. The shim of the copper
sheets was also used to adjust the position of the coils.
In order to verify that three quadrupoles were properly fabricated, we tested each quadrupole using aliquid-He open dewar. We measured the field gradients, performed a quench protection test, and observed
acoustic emissions. Table 2 summarizes the test results.
The three quadrupoles were successfully excited
without quenching up to 163 A, which is about 120% of
the maximum operation current. The field gradientswere measured by a Hall probe installed in the pole
gap. Excitation curves were found to match well withcalculations.

351

Table 3. Dewar test results.

Maximum field gradient(1'/m)
Maximum current(A)Maximum excitation rate(Als)
QuenchDetected Voltage in the quench
test with heater (at 135A)
Stability judged from acoustic
emission

Q500
A
15.2
163
1
No
16G

Q800
15.6
163
0.75
No
284

-1.6

-1.2

8
~

1

I

C)

t
I

I

-0.8

~

,

:

i.
i

~

i

I

I

~

i

!1 :

i

!

Ii

i i I 1 I

I

I

,I

!

, ! I
, ! ! !

!

!

50

II

I

i

!

;
I !I I
i

,

I

! i

!I i

,

!

o

I

!
!

!

I

! i
I ! I

0.2

,

I

I

i~ I I I

I

;

j

:
,

I~

I

0

•• i
!

!

.1

-0.2

i

i

I : ..,.

-0.4 I-t---t-"
~ i

b.O
C\S

fi

!

j

I :
: i 1.~!

I i

! !

i

:

! :

I

-0.6

~

Stable11iQ)

Stable

; ,

i i

-1

~

Stable

I

I

'"0

.~

The quench protection test was performed at 136 A,
corresponding to the maximum operation current, using heaters attached to the coils. A quench was artificially generated by turning on the heaters at 3 W for a
few seconds. We measured the coil voltage generated
by quenching and compared it with the prediction by
the quench analysis. 2 ) The coils were designed to be
self-protected against quench, so that they can survive without an external resistor. The quench analysis
without the external resistor 2 ) revealed that the generated coil voltage of the Q800 reaches 670 V, which
is far below our design criterion, 1 kV.2) In the caseof the Q500, a lower voltage is produced because it
has a smaller inductance. However, in the test, an
external resistor of 0.48 n was used due to the restrictions of the test facility. The measured voltages arelisted in Table 3. In the case of the Q800, the coilvoltage was measured to be 284 V, while the quench
analysis with an external resistor predicts the voltage
to be 310 V. This indicates that the quench analysis
can well predict the voltage and hence the predictedvoltage without the external resistor is reliable. It canbe concluded that the coil is self-protected.
Mechanical stability of the coils was tested by observing the acoustic emissions produced by movementof the coil or superconducting wire. An event rateof the acoustic emission increased as the current increased during a virgin excitation. However, the event
rate decreased as the current increased after the virgin excitation, which indicates that the coils became
stable.
We performed a cooling test and an excitation test
after the quadrupoles were assembled and installed in
the cryostat. The consumption rate of the liquid-He
was measured to be 3.1l/h when the magnet was not
excited, while the consumption rate of the liquid-He
was measured to be 4.1l/h when the magnet was excited at 146 A. These consumption rates are almost thesame as those of the design values. Each quadrupolewas excited up to 165 A without quenching. Field gra-

352

-1.4

Q500
B
15.3
16:1
1
No
157

I ;I

100

i

I
I

150

200

Current (A)Magnetic field By at x = 100 mm, Y = 0, and z = o.
• indicates measured magnetic fields.
• indicates calculated magnetic fields.
Fig. 5. Excitation curve of the Q800.

30.0

~800

1'-25.0

Q500A
20.0

E 15.0

II!"

'"

~

Q500B~~~-l--L(Q800)'1 -- L(Q500A)

-u
.....

, -ir- L(Q500B)-m

L-e- L( Q500

10.0

de~ign)

5.0
0.0
0.0

100.0

50.0

150.0

I(A)

Fig. 6. Inductance vs. excitation current.

dients were measured by a Hall probe installed in thepole gap. Excitation curves were found to match thecalculations well, as shown in Fig. 5. Figure 6 shows
the inductance derived from the measured current andvoltage. The inductance decreases as the current increases due to saturation.
The prototype of the superferric quadrupole magnet
has been successfully fabricated. As the next step, aprecise field-map measurement will be performed in
the near future.
References
1) T. Kubo et al.: RIKEN Accel. Prog. Rep. 33, 238(2000) .
2) T. Hirumachi et al.: IEEE Trans. Appl. Supercond. 10,
238 (2000).

RIKEN Accel. Prog. Rep. 34 (2001)

Prototype of Superferric Quadrupole Magnets
for the BigRIPS Separator (II)T. Tominaka,*l T. Kubo, H. KOUZU,*2 K. Kusaka, M. Okamura, Y. Yano, T. Senba,*l and S. Suzuki*l
A superferric quadrupole with superconducting sextupole and octupole coils has been constructed as aprototype for the projectile fragment separator named
BigRIPS.1) In our previous report, we designed two
types of superferric quadrupole called Type A andType B. 2 ,3) The fabrication of the quadrupole in thepresent report is based on the design of Type B.
The fabrication of Type A quadrupoles is described
elsewhere. 4 ) In this report, the design and constructionof Type B superferric quadrupole magnet with superconducting sextupole and octupole coils are described,
together with the experimental results.
The original design of these quadrupole, sextupole and octupole coils, which have been developed as the superferric quadrupole magnet system at NSCL/MSU 5 ) was based on results of a
two-dimensional magnetic field calculation performed
mainly with OPERA-2d, and those of a threedimensional magnetic field calculation performed withTOSCAjOPERA-3d. 6 ) The main parameters for one
Type B superferric quadrupole magnet system arelisted in Table 1. The mechanical parameters are also
listed in Table 2. The cross section and schematic
view of the prototype quadrupole magnet are shownin Figs. 1 and 2.
In order to reduce the 12-pole component (b6) due tothe end effect of the iron pole, a chamfer is adopted .
The reduction of the 12-pole component results in abetter uniformity of the gradient field. With the chamfer , the uniformity of the field gradient is greatly improved in the low-excitation region, but the uniformity
Table 2. Mechanical parameters of prototype quadrupole
magnet.
Inner tube for correction coils
Inner diameter (rrun)
Outer diameter (mm)Outer tube for correction coils
Inner diameter (rrun)
Outer diameter (mm)Pole tip radius (rrun)
Iron yoke
Inner diameter (rrun)
Outer diameter (mm)Length of iron yoke (rrun)

Field intensityQs

Octupole coil
Quadrupole coli

14.1

15

40

(T/m2)(T/m 3)

253

28.2

10.1

Nominal current (A)

158

48.6

48.1

Tum number

1600

580

210

Nominal current density(A/nun 2)

115

84

86

Nominal current per pole
(kA)

*1

*2

Peak field on conductor (T)

3.8

2.9

2.9

Cross section of coil (mm 2)

2209

335

118

Shape of cross section
Opening angle (pole angle)& thickness [for shell]rectangular
47 nunx47mm

shell
59(21) deg
x 6.5 mmshell
44(16) deg
x 3.0 nun

Inner radius (nun)

152.0

159.5

Outer radius (nun)

158.5

162.5

Straight length of coil (nun)

450

445

465

Total length of coil (mm)

",630

",600

Nominal effective length
(nun)

500

"'600
500

Inner tube forcorrection coils

960mm

Fig. 1. Cross section of prototype superferric quadrupole
magnet (B).

500

Inductance (H)

'" 27

1.3

0.38

Winding of coil

Semiorderly

randomrandomHitachi , Ltd.
Toshiba Corporation

Outer tube forcorrection coils

0

(Tim)

295
480
450

Iron yoke

Table 1. Main parameters of prototype quadrupole (Q),sextupole (S) and octupole (0) coils.
Coil

SUS316L
144
151
SUS316
163
166
170

Fig. 2. Schematic view of prototype quadrupole magnet(B), together with sextuple and octupole coils (graphical output of calculational model for TOSCA).

353

is a slightly deteriorated in the high-excitation region.
We think that the uniformity is improved over the entire excitation region with the chamfer. A comparison
between with and without chamfer is also given in Table 3.
All flat quadrupole coils are wet wound with Stycast 2850 FT epoxy and Catalyst 11 in a winding form
with a V-shaped groove. As the cross section of thequadrupole coils is diamond-shaped, the latter half ofwinding is not carried out in a winding form . After the
R&D of winding, the coil is cut to observe the crosssection. It is observed that the winding of the initialhalf is a slightly more dense than that of the latter
half. After winding, the two outer surface planes arepressed with a jig for the trimming treatment of thecross-sectional shape. The coils are then oven cured.
The surfaces of the coils are finally treated with Stycast 2850 FT epoxy and Catalyst 9. A set of four coils
is then assembled around the pole tips. The coils areshimmed in place with SUS and GFRP spacers. All
sextupole and octupole thin coils are also wet wound
in a racetrack shape with Stycast 2850 FT epoxy and
Catalyst 11 in a flat winding form. The sextupole andoctupole coils are then deformed into a saddle shapeand oven cured. Finally, the sextupole and octupole
coils are assembled on the tube of SUS316L (designed
as the inner tube of a helium vessel), together with
the insulating plate of GFRP and then rigidly fixed
to the outer SUS tube and the key connecting the inner and outer tubes to sustain a large electromagnetic
force. The parameters of the superconducting wires
are summarized in Table 4.
In order to verify the magnet performance, the prototype magnet has been tested in an open verticallyoriented helium vessel up to 120% of nominal operation
current . One quench for the quadrupole coil at 119% of
nominal operation current and one quench for the sextupole coil at 120% of nominal operation current on the
excitation of the octupole coil were observed. For therough measurement of the magnetic field produced dueto the quadrupole, sextupole and octupole coils, seven
Hall probes were installed in the middle plane verticalto the magnet (or beam) axis. As a result , an agreement between the measured and calculated results has
been obtained, as shown in Fig. 3. In Fig. 3, the measured results are indicated by stars, and the calculated
results by diamonds. In order to measure the strain of
the supporting tube sextupole and octupole coils dueto the electromagnetic force, four strain gauges were
installed on the inner supporting tube. As a result ,it was confirmed that the measured azimuthal strain(1.7 x 10- 4 ) roughly agrees with the calculated value(1.3 x 10- 4 ).
The superferric quadrupole magnet with correction coils which produces field intensities of 14.1 Tim,
15 T 1m2 , and 40 T 1m3, over a 120-mm radius with uniformity of approximately 0.5%, have been constructed

354

Table 3. Comparison between with and without chamfer.
Type

With
chamfer

Without
chamfer-

Chamfer
Axial and radial lengths (mm)19 x 30

Field gradient (TIm)

4.0-14.1

4.0 - 14.1

Current per pole (kA)

46.1 - 253

46.1 - 253

Effective length (m)0.544 - 0.513

0.555 - 0.515

b6 (x 104 )-23.5 -40.8-43.2 - 35.9

blO (x 104 )-2.0 - 2.6-1.4 - 2.5

Table 4. Main parameters of superconducting wire for prototype quadrupole (Q) , sextupole (S) and oct up ole (0)coils.
SandO

Coil

Q

Insulated diameter (mmC\»

1.15

0.71

Bare diameter (mm</l)

1.10

0.648

6.6

4.0

100 - 150

100 - 150

Filament diameter (~mC\»

75

45

Number of filament

28

42Insulator

FormvarFormvarIe (A)

415@4T,4.2K

250@3T,4.2K

Culsuper Ratio
RRRofCu

15
12.5
10
7.5

100

50
I

150

(A)

Fig. 3. Comparison between measured and calculated excitation curves of field gradients.

and successfully tested with the confirmation of theirmagnet performance.
References
1) T. Kubo et al.: RIKEN Accel. Prog. Rep. 33, 236(2000).
2) T. Kubo et al.: RIKEN Accel. Prog. Rep. 33, 238(2000).
3) T. Hirumachi et al.: IEEE Trans. Appl. Supercond. 10,
236 (2000).
4) H. Kouzu et al.: RIKEN Accel. Prog. Rep. 34, 350(2001) .
5) A. F. Zeller et al.: IEEE Trans. Appl. Supercond. 9 ,693 (1999).
6) OPERA-2d and OPERA-3d/TOSCA, Vector Field,
Ltd., Oxford, UK.

RIKEN Accel. Prog. Rep. 34 (2001)

Pulsing Magnet Power Supply for the RIKEN RI-Beam
Factory Project
H. Kouzu,* T. Kubo , K. Kusaka, Y. Yano, Y. Chiba, C. Yamazaki, * and T. Saito*
In the RIKEN RI-beam factory project ,l) radioactive isotope (RI) beams will be produced using projectile fragment separators called BigRIPS.
Two
BigRIPS separators will be constructed, so that two
different RI-beam experiments can be conducted at
the same time. These two BigRIPS separators will
share primary beams from the SRC cyclotron by meansof time sharing. A pulsing dipole magnet will be installed in the beam line from the SRC cyclotron to
the BigRIPS production targets. The primary beams
will be transported to one line when the pulsing dipole
magnet is excited. On the other hand, they will betransported to another line when the pulsing dipole
magnet is not excited. A power supply for the pulsing
dipole magnet has been designed and fabricated. In
this report, we describe the design and the test resultsof the pulsing dipole magnet power supply.
As regards the type of pulsing dipole magnet , wechoose a c-type dipole magnet with a bending radiusof 5.5 m and a bending angle of 20 degrees. The fieldstrength is 1.41 T and the pole gap is 60 mm. The main
parameters of the pulsing dipole magnet are listed inTable 1. The pulsing magnet is large compared withordinary pulsing magnets.
The pulsing magnet will be operated in both pulse
and DC modes.
In the case of the pulse mode,both flat-top period and flat-base period are 450 ms or
longer. Its operation pattern is shown in Fig. 1. The
output current is 0 A during the flat-base period. Bothflat-top and flat-base periods can be changed dependTable 1. Parameters of the pulsing magnet.
Malmetic rigidity
Bending radius
Bending angle
Dipole field strength
Pole gap
Turn number per pole
Hollow conductor size
Nominal current
ResistanceInductanceGood field region
Magnetic field uniformity
Weight7.52Tm5.5m
20degree
1.41T
60mm
24
13.5mm x 13.5mm- <p 8mm
1445A
33.3mO25.9mH± 50mmBetter than 4 x 10 •6.3t

ing on the requirement of the experiments. Furthermore, the ratio of these two periods can be changed aswell.
The switching time should be as short as possible since primary beams cannot be delivered to the
BigRIPS during this period. We aimed at a switchingtime shorter than 50 ms. Current accuracy, such as
ripples , long-time stability, and reproducibility, is required to be better than 1 x 10- 4 p-p for both flat-top
and flat-base periods. The current accuracy for theflat-base period is defined in terms of the flat-top current. This current accuracy must be achieved within
50ms.
The pulsing magnet power supply consists of two
circuits: one is a forcing circuit and the other is themain circuit. These two circuits are connected in series. A schematic block diagram of the circuit is shownin Fig. 2. The forcing circuit provides the pulsing magnet with a high voltage in order to quickly raise thecurrent from the flat-base to the flat-top. On the other
hand , the main circuit controls the current accurately
by using a transistor dropper. This current control
begins to work when the current almost reaches theflat-top. In the case of the DC mode, only the main
circuit is operated. The main parameters of the pulsing magnet power supply are listed in Table 2.
The operating sequence of the pulse mode is as follows:
Sequence 1: Two gate turn off thyristors (Gl, G2) inthe forcing circuit and a transistor dropper (Tr) in themain circuit are turned on. The current rises quickly
due to the high voltage produced by an electric charge
stored in a condenser (Cl) in the forcing circuit.
Sequence 2: G2 is turned off and Tr in the main circuit
starts controlling the current just before the current

load

1.TI, T2: Transformer
CI , C2: Condenser
GI, G2: Gate turn off thyrister
Tr:
Transistor dropper
CT :Current transformer
Fig. 1. Operation pattern of the pulsing mode.
Toshiba Corporation

Fig. 2. Schematic block diagram of the pulsing magnet
power supply.

355

Table 2. Parameters of the pulsing magnet power supply.
Maximum output current
Maximum outpu t voltage
Load resistanceLoad inductance
Ripp leReproducibility
Stability
Operation mode
Rising switching time
Descending switching time
Flat top time
Repetition period

Table 3. Test results.
RippJe(@1600A)
RippJe(@800A)
Stability(@1600A)
Stability(@800A)
Reproducibility(1600A)
Reproducibility(800A)
Rising time(@1600A)
Rising time(@800A)
Descending time(@1600A)
Descending time(@800A)

1600A
2170V
33.3mQ25.9mH;:;;! 1 x lO - ·p· p(* 1)~ 1 X 10 'p.p(* 1);:;;! 1 X 10 'p.p(* 1)
PulselDC;:;;!50ms;:;;! 50ms

2.9 X 10 ''pop
5.1 X 10 "p.p
1.0 X 10 .p-p
1.0 X 10 ' p-p0.45 X 10 'pop
0.33 x 10 .p.p
35ms
44ms
17ms
llms

~450ms~ Is(* I)Ranging from 50% of maximum current to 100%.

reaches the flat-top current.
Sequence 3: The current is accurately controlled by Tr
during the flat-top period.
Sequence 4: Gland Tr are turned off. Energy stored
in the pulsing magnet recovers to Cl and the current
decreases towards the flat-base. The power supply isswitched off and the output current is not controlledduring the flat-base period.
The maximum output current and voltage are chosen to be 1600 A and 2170 V, based on the design of thecircuit and the pulsing dipole magnet. The maximum
current is chosen to be 10% larger than the magnet
current listed in Table 1, because the design of thepulsing magnet has not been finalized .
In designing the power supply, we have made circuit
simulation by using the code EMTDC,2) in order tofind the conditions that achieve the required current
accuracy within 50 ms. It is found that the output
current must rise as fast as 20 ms, and current control
by the transistor dropper must begin when the output current reaches about 98% of the flat-top current.
This is because it takes t ime to damp current fluctuation. The output voltage is determined based on thesimulation results .
We fabricated the power supply, and performed atest operation by using a test load in order to measure switching time and current accuracy. The inductance and the resistance of the test load are 5.6 mR and10.5 mn, respectively. Voltage in the test is lower thanthat in the case of using the pulsing magnet because
the inductance of the test load is lower than that of thepulsing magnet. The output voltage is about 800V.
The operation test was performed at 1600 A and800 A, respectively. The test results are summarizedin Table 3. In order to optimize the rising switchingtime, the timing of sequence 2 is adjusted during themeasurement . An example of observed output currents
is shown in Fig. 3 for the case of rising. The risingswitching time at 1600 A and 800 A are measured to
be 35 ms and 44 ms, respectively. The rising switchingtime of 800 A is longer than that of 1600 A, because
the turn-off time of G2 is optimized for 1600 A. An
example of observed output currents is shown in Fig. 4
for the case of descending. The descending switchingtime at 1600 A and 800 A is measured to be 17 ms and356

Fig. 3. Example of observed currents for the case of rising.

I

~

~

I

I I

~....-+ -1'1

Fig. 4. Example of observed currents for the case of descending.

11 ms, respectively. These values well achieve the requirement. Long-time stability and reproducibility are
well achieved.
It is expected that the similar results will be obtained when the actual pulsing magnet is used as theload, although some adjustments are needed.
The specifications required for the pulsing magnet
power supply have been achieved. The power supply
will be tested again in the combination with the pulsing
magnet to be fabricated in a few years.
References
1) Y. Yano et aL: Proc. 15th Int. Conf. on Cyclotrons andTheir Applications, Caen, France, (1998) p .696.
2) EMTDC, Manitoba HVDC Research Centre, Canada.

RIKEN Accel. Prog. Rep. 34 (2001)

New Lattice Design of ACR for MUSES
K. Ohtomo,* T. Tanabe, N. Inabe, M. Wakasugi, and T. Katayama
The Accumulator Cooler Ring (ACR)l) is newly
designed to study the accumulation and cooling of
RI beams for Multi-USe Experimental Storage rings(MUSES). RI beams with large momentum spreads
and emittances, after passing through a fragment projectile separator (Muses-RIPS), should be manipulated
before injecting them into the ACR. The longitudinal momentum spread of dp/p = ±O.5% is reduced
to ±0.15% by debuncher cavities 2 ) located 80 m downstream from the M-RIPS. The transversely horizontal
emittance is expected to become large due to a degrader in the M-RIPS.3) Solenoids or skew quadrupoles
should be installed in the injection beam line to transfer emittance from the horizontal plane to the verticalone. A rapid repetitive cycle of multiturn injection
and RF stacking is required to build up a RI beam
current. The cooling time required in electron cooling(EC) and stochastic cooling (SC) should be approximately as small as the RF stacking time, which is a50-100 msec period. The lattice of the ACR should bedesigned to fulfill the following conditions which areimportant for rapid cooling and effective accumulation.

(1) A large acceptance in the horizontal plane(Ax = 125i mm mrad) , in the vertical plane (Ay =407r mm mrad) and a large momentum spread acceptance (tJ..p/p = ±l.O%).
(2) A long dispersion-free space (10 m long) withsmall {3x function (less than 5 m) for the EC.
(3) A pair of dispersion-free spaces (6 m long) for
the SC pickup and the SC kicker. The betatron phaseadvance tJ..p,pk between them should be k7r /2 (k: odd
integer) and the local transition 'Yirk should be nearly
the same as relativistic 'Y for efficient cooling. 4 ) Here,'Yirk is defined as1- -2 = a pk = ""pkItr

1 lsckicker D~dstJ..L SCpickupP,

where a pk is a local momentum compaction factor, tJ..L
the distance from the SC pickup to the SC kicker, Dx
the horizontal dispersion, and P the curvature of theorbit.
(4) A space with certain dispersion (3 m long) for
multiturn injection. A pair of spaces, where the beta-

to

lJ..
CI
Q.

.... II)<t<t;;~OlJ..O

zo
::!i"

"::!iCl ClCl
Co

()
rJ)

Parameters of ACR
Circumference [m]Orbit Width and Depth [m]Magnetic Rigidity [Tm]
Max. Acceptance Ax andAy [ltIrun.rnrad]Max. Momentum Spread Acceptance [%]Injection Emittance Ex and &y [1tmm.rnrad]
Injection Momentum Spread [%]Betatron Tune Qx I Qy
Transition Ytr__.__--- _.
't

tll
(t

Ql

3

()

III

W
OJ
()

lJ..
D:

Cooling
Isochronous
mode
mode
134.787

50.7/29.8
4-8

125/40

5/40

±1.0

±D.2

5/40

5/40

±0.15

±0.15

3.228/2.575

1.325/2.292

2.562

1.302

..

.... II)<t<t~~OlJ..O"::!iClClCl

~

"'(')

~o
::!iCl

tll
(.0)

~

()
rJ)

Fig. 1. Layout of ACR with parameters.
Sumitomo Heavy Industries, Ltd.

357

40r-----~----r_----r_----r_----r_----r_----r_----r_----r_--~1m)
Horlzon1al
betatron--+----+-~/

flmction

betatronflmction

1m)

Horlzon1al
dispersion
flmctiono I---r'r---ro134.

-zo~----~----~----~----~----~----~----~----~----~--~

Fig. 2. Twiss functions.

tron phase advance is nearly 7r between them, is also
required for the installation of bump magnets.
(5) A dispersion-free space (3m long) for a tunable
RF stacking cavity.
According to the above requirements, the ACR lattice has been designed using MAD5) and WinAGILE.6)
The resultant layout with parameters and Twiss functions is shown in Figs. 1 and 2.
The ACR consists of two types of lattice arcs which
are connected in long straight sections. One lattice,called A-arc, has large dispersion to satisfy condition(3) mentioned above. Another lattice, B-arc, has relatively small dispersion to satisfy condition (4) and toadjust betatron tunes of the total ACR.
The A-arc is described as follows:
A-arc = SC- QD3-B-B- QF2- QD2- B- QD1- BQF1- B-QD1- B- QD2-QF2- B- B- QD3- SC,
where QF1,2 and QD1 ,2 are focusing and defocusing
quadrupoles, respectively, and B is a bending magnet.
The dispersion function increases along the bendingarc and reaches the maximum of 15.3 m at QFl. The
total arc functions as a dispersion suppressor. From
the SC kicker to the SC pickup, ~/-L~k and b./-L~k are
37r /2 and 'Yfrk is l.688.
The B-arc is described as follows:
B-arc = B- B- QD7- QF7- INJ- QF8- QD8- B- BQF9- QD9- (symm. )- QD9- QF9- B- BQD8- QF8- QF7-QD7-B- B,
where QF7,8,9 and QD7,8,9 are focusing and defocus-

358

ing quadrupoles, respectively, and INJ the injection
point. The B-arc is a two-folded structure and eachhalf-arc is a dispersion suppressor. The injection point
is located at the first arc where the dispersion has amaximum of 4.38 m in the B-arc. Also, the tune of the
B-arc is adjusted so that the total horizontal betatrontune Q x becomes 3.228, nearly kj4 (k: odd integer) ,to obtain good efficiency by multi turn injection, andthe total vertical betatron tune Qy becomes 2.575, farfrom the strong resonance lines.
The connection section is described as follows:
STR = QD4- QF4- QD5- (EC or EXT)- QF5- QD6RF- QF6,
where QF4,5,6 and QD4 ,5,6 are focusing and defocusing quadrupoles , respectively, RF the RF cavity, andEXT the extraction. The horizontal and vertical betatron functions at the center of EC are 4.03 m and14.34 m, respectively, enabling the electron flow of the
EC to cover RI beams with large emittance.
The total ACR is described as follows:
ACR = A-arc-STR(EC)- B-arc- STR(EXT).
The large-momentum spread operation requires sextupole magnet correction. However, an excessive sextupole correction results in a reduction of the dynamic
aperture. The dynamic aperture with bare lattice andsextupole correction was determined and it was verified to be several times as large as the designed valueof acceptance. Also, 20000 turn tracking has been performed with particles having dp/p of ±1 % and bound-

2000
1800

~

1600

~

1400

c:

10 tumS/Septum Thick.
- .-2mm676%_ _ 4mm 650%
- 4 - 6mm 624%

20 tums/Septum Thick.
· ... .. · 2mm1174%...•... 4mm 1085%-- ..... .. 6mm 856%

a.

1000

~

32

800

..0

600

c:
0

~ 1200.'.•.•.'>-

g 1000

'

1200

'5

1400

... .. ....

. . ......
.
.
.. ...'
.
.' .'

Q)

'0

IE
Q)

40 tums/Septum Thick.
.. ··· . .. ·.. 2mm1688%• . 4mm 1128%..... &-.... 6mm 567%

n

400

E:

200

.

.' .'
. . •.•. .'

.!!!
u

~

~

~

........... .. ..............

Cl

c:
:i:
u

400

.!!l

........

(/).........
10

600

.a

.. . .. .. .. .....
.. ... ... ..

'

Q)

800

a.

200

0

20

30

40

Turn number

Fig. 3. Multiturn injection efficiency with various parameters.
Bump fields decay linearly.
Injection
beam emittance is 57r mm mrad, ACR acceptance is1257r mm mrad, injection beam momentum displacement is + 1%, and injection beam momentum spread
is ±0.15%.
ary emittances ExlEy of 150/487r mm mrad; all particles have survived.
Multiturn injection efficiency was determined with
fixed parameters, which are the injection beam emittance and acceptance in Fig. 1, and optimized parameters, which are the turn number of multiturn, thicknessof injection septum, and betatron function of injection
beam line. It was proved that the total buildup efficiency reached about 1000%, as shown in Fig. 3.
The RF stacking process has been simulated in thesame manner as the optimized parameters, which are
the stack number of RF stacking, and the initial and final RF voltages. It was observed that the total buildup
efficiency reached about 1000%, as shown in Fig. 4.
Currently, the cycle of multiturn injection, RF stacking, and cooling is expected to be 5- 10 Hz and the total

0

10

15

20

Stacking number

Fig. 4. RF stacking efficiency with various RF voltages.
Vcap is the initial RF voltage at the capturing process,whereas V comp is the final RF voltage at the compressing process by RF buckets.
beam current might be built up 600- 2000 times the injected beam at the AeR.
The isochronous mode operation in Fig. 1, whichmeans that the ACR will be used as a mass spectrometer of RI beams, should be studied carefully in the
future.
References
1) K. Ohtomo et al.: Proc. of European Particle Accelerator Conf. 2000, p.566 (2000).
2) K. Ohtomo and T. Katayama: RIKEN Accel. Prog.
Rep. 31, 225 (1997).
3) C. C. Yung: MUSES Meet. (2000).
4) M. Wakasugi et al.: Proc. of European Particle Accelerator Conf. 2000, p.1274 (2000).
5) H. Grote and F. C. Iselin: CERN/SL/90-13 Rev.5(1996).
6) P. J. Bryant: Proc. of European Particle Accelerator
Conf. 2000, p.1357 (2000).

359

RIKEN Accel. Prog. Rep. 34 (2001)

Space-Charge-Dominated Ion Beams Cooled by Electron Cooling
M. Takanaka
At low energies, a high-current beam is led tobetatron-tune shift, resonance trapping, emittance
growth, and instability by a self-induced field. Electron cooling is a very effective method for decreasing
longitudinal and transverse emittances of low-current
beams. When ion beams are stored, electron-cooled,and stable in a ring, how large are the beam currents?
In order to answer this question, we studied spacecharge-dominated beams using beam-tracking simula:tion.
In the beam-tracking simulation, we took the following sources of force into account: (1) longitudinal monopole space-charge impedance, (2) transverse
space-charge field, (3) transverse dipole broadband
impedance based on the broadband impedance model,(4) electron-cooling force, (5) solenoid field of theelectron-cooling section, (6) beam twist due to thetoroid field at both ends of the electron-cooling section, (7) a constantly focusing section and the drift
electron-cooling section of which the ring is assumed
to consist, and (8) RF field for beam bunching.
Using 40,000 macroparticles, we simulated u~~t ion
beams at 150 MeV lu. Table 1 shows the parametersof the ring and the electron cooling used for the simulation.
We present the simulation results of coasting u~~t
ion beams of 33 rnA and 330 rnA and the results ofa bunched beam of 33 rnA. The beams initially had
a Gaussian momentum distribution with a spread of
10- 3 at sixfold rms, and transverse rms emittances of
10- 6 mxrad and 2 x 10- 6 mxrad for the beam currentsof 33 rnA and 330 rnA, respectively.
Figure 1 shows the evolution of the coasting beam of
33 rnA. The electron cooling is evidently more effective
in decreasing the momentum spread than in decreasing the transverse emittances. The momentum spreadreached an equilibrium at 13 ms. Figure 2 shows thatthe beam has a dense core at the center of the crosssection. Part of the beam betatron oscillates with abetatron amplitude several times larger than the core.
Ions in the core have their incoherent tunes shifted
over 2 and are isolated from the rest. This indicatesthat even if part of the core beam is trapped into a
resonance due to imperfection of the ring magnets, itescapes the resonance easily because a very small increase in the betatron amplitude causes a large tune
shift, and that the electron cooling confines the beamtransversely.
Since the core beam has a very small betatron amplitude, it is difficult to observe the tune of the core
beam practically using monitors.
Figure 3 shows the evolution of the coasting beam of
330 rnA. The electron cooling was not sufficient for the
momentum spread and the transverse emittances todecrease. Figure 4 shows that there is no core structure
due to the electron cooling evident from the transverse
beam profile or the betatron-tune distribution.
Between 33 rnA and 330 rnA is a threshold of beam
current at which beams are confined by the electron
cooling.
101

1.2:0CI:I
....

*S

10°

~ 0.8

a 0.6

10. 2

's 0.4

10- 3

t:

tU

a
....

g

'"

'"e
~

0.2

10- 4 E0

10. 5 E

ac::

~

~

'J:i

c.o~

Q)
()

~

E

*
ci.
1
10. c..

'D~

§

~

tU

0

E-<

5

10

15

25

20

Time (ms)0::sFig. 1. Evolution of a coasting u~~t ion beam of 33 rnAduring electron cooling. The bandwidth of the longitudinal space-charge impedance changed from 13 GHz to
16 GHz at 21 ms.

Table 1. Parameters of the ring and the electron cooling.
Circumference 271T
Transition,
Betatron tune (v x / Vy)
Chromaticity (f"x / f"y)Beta function ({3x / {3y )Beta function at EC section center ({3; / {3;)Inner radius of the chamber
RF harmonics
Electron current
Section length
Electron beam radius
Cathode temperature kTc
Solenoid field
Expansion factor

360

134.8m2.562
3.228/2.575
0.0151/0.0001
r/vx/r/vy
4.0/14.3m
4.0cm
16
4. A
3.6m
28.4mm
O.leV
2kG
20.

No. of particles

IO
IO
IO

0.5
-5

x (mrn)oIOx(mrn)

Fig. 2. 'Transverse beam profile and betatron-tune distribution of the coasting u~~t ion beam of 33 rnA at 25 ms.

::0til

...

3

,}~

2.5

*S

g

6

ex

2

·s~

1.5

4

0.

~

til

E!::

~

c.o.
"0

's "g~ 0.4

'-"'

t:

~

2

op/p

Q)

§ 8 0.2

~

S

0.5

1A B
~ ;3
;> 8

B
;::
Q)

0

0

5

10

15

20

~

Time (ms)Fig. 3. Evolution of a coasting u~~t ion beam of 330 rnAduring electron cooling.

L--LL-_L-_L-_L-_L-_L-_L-~O

j ~

S
0

0

E

b_ c.o-a: 08.
.
8b~ :::: 0.6

~

Q)

;::

~

E ~.

til

§
~

5

3

Q)

Q)

~

*
\0

ci.

ey

Q)

u

::0- ';ii' 1.2 ~-'----'----'---'---.---.---r---, 15

4

12

8

.. 3.5 . - - - -- - - - ---,"· r;~'.:l·",;.~:(I" .

>'" 3.25::?:~ ~ " ;:;;.:> 'tIWrl~?": '

40
35
30
25
20
15
10

3.15~

'

'.

-. " f~/'

3.1~

3.051-o3
15 10 5
x(mm)

0

28

32

3~
2.5 f--

2 F-·"- ·T·- ~-.,"'"<',~; '~ .

:\ .~:'1,..

. :. ':! ~.~'

1.5 ~

'

, ~.:.

I f--

3 .075~3.025~

24>" 3 . 5 . . - - - - -- ----,.

.

3.125~

5

20

Fig. 5. Evolution of the bunching of a u~~t ion beam of
33 rnA during electron cooling.

;>

No. of particJe.._s:r::-::--_ _ __16

Time (ms)

I

-10

-2
I

o

I

o

2
Cl>rf(rad)1..l...L.L.L.l1--'-..L.L.LJ
0.5 t::..L.l--'-..L.LL.
1LLJ.-1.
-10
-5
0
10

x (mm)

10x(mm)Fig. 4. Transverse beam profile and betatron-tune distribution of the coasting u~~t ion beam of 330 rnA at 20 ms.

After the coasting beam of 33 rnA was cooled to a
momentum spread of 4.5 x 10- 4 , it was bunched using
an RF system. During the bunching, the RF voltage
increased in such a way that the momentum spread wasmaintained at 4.5 x 10- 4 . Figure 5 shows the evolutionof the bunching. After 25 ms, the momentum spread
did not decrease, and the RF voltage was constant. In
contrast, not only did the vertical emittance increaseat 11 ms, but also the horizontal emittance slowly increased at 20 ms. Figure 6 shows that the bunchedbeam loses a dense core at the bunch center. The electron cooling became insufficient to confine the beam at
the bunch center where the instantaneous beam cur-Fig. 6.
Incoherent betatron-tune distribution of thebunched u~~t ion beam of 33 rnA along the bunch at
20ms.

rent was 150 rnA.
By a beam-tracking simulation of a space-charge
dominated beam, we confirmed that the beam confined by the electron cooling contains a small, dense
core or cores. The ions in the cores have their incoherent betatron tune shifted largely, for example, over 1
by the space-charge effects. We ensure d t h at U 92+.
238 IOn
beams of 150 MeV lu can be confined to about 150mA
at the instantaneous beam current in the ring with theparameters listed in Table 1.
In analyzing the results of the simulation, checking
whether beams contain the cores or not becomes an important factor for determining the beam confinement.

361

RIKEN Accel. Prog. Rep. 34 (2001)

Development of the Kicker Magnet for MUSES
T. Ohkawa,*! T. Takeuchi,*2 M. Wakasugi, and T. Katayama
In the MUSES project, kicker magnets are used forthe ion-beam injection and fast extraction. The injection kicker field must fall from approximately 90%
to 10% of the full strength and the extraction kicker
field must rise from approximately 10% to 90% of thefull strength during the time interval between bunches.
The high performance of the kicker magnet is important in the efficiency of beam injection and extraction.
In this paper, the development of kicker magnets for
MUSES are presented.
We have adopted a traveling-wave-type kicker magnet, which is often used to generate a high magnetic
field with a rapid rise and fall time.!) When the PFN
is charged at 100 kV , the kicker magnet is expected to
produce a magnetic field of 0.084 T with a flat top of
1 J-LS and a rise time of 95 ns. The design parameters
are listed in Table I and a photograph of the kicker
magnet is shown in Fig. 1.

As shown in Fig. 2, the power supply of the kicker
magnet consists of a DC high-voltage power supply, a
PFN, a thyratron, and a terminator. Table 2 presents
the parameters of the power supply. We use the transmission cable with a length of 100 m so that reflectedcurrent does not disturb the waveform at the flat top.
To avoid the mismatch of impedance between the
kicker magnet and feedthrough , we have developed a
feedthrough with a coaxial structure whose characteristic impedance is designed to be 25 n. The structureof the feedthrough is shown in Fig. 3.
The impedance of the feedthrough from the connector to the inlet of the kicker magnet measured by the
TDR method is shown in Fig. 4. The result of the measurement shows that the impedance of the feedthroughis approximately 27 n except at the part of the connector.
A current transformer (PEARSON-IIO) and asingle-turn long search coil are used for the measure-

Table 1. Parameters of the kicker magnet.

Thyratron
ITEM
Gap heightGap width
Total core length
Cell number
Inductance of unit cell
Capacitance of unit cell
Characteristic impedance
Gap field
Coil current
PFN voltage
Field rise time

DESIGN VALUE
30mm
130mm
225mm
9

0.l36 J.1H
108.9 pF
25Q
0.084 T
2000 A
100kV
95 ns

Fig. 1. Photograph of the kicker magnet.

r------.

PFN
DC high-voltag
power supply

Transmissio
cable

KickermagnetFig. 2. Schematic of the kicker magnet system.
Table 2. Parameters of the power supply.

ITEM
Charging voltage
Current
Pulse width
Pulse interval
Repetition
JitterThyratron
Termination resistance

DESIGN VALUE
100kV
2000 A1125 ns
more than 0.3 s
1 Hz
±5ns
CX1l71 (EEV)
24±2Q(variable)-7Cable

*1

*2

362

Mitsubishi Heavy Industries, Ltd.
Center for Nuclear Study, Graduate School of Science, University of Tokyo

Fig. 3. Structure of the feedthrough.

50

§
G)

~

~

G)

:>

40
30 \

C

~-

1.60

0.16

0.80

0.08

0.00

0.00

~
cu

-----/

'E;;-

20

§ 10

~

C)

=
..s
~

o L -_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
0.1
0.2
0.3
0.4
o
~

Connector

~

~

~

1.1::
.~

6h
cu

::E

-0.16

-1.60
Time (ns)Fig. 6. Magnetic field and induced voltage.

Fig. 4. Impedance of the feedthrough.

0.1

2500

p 0.08:s 0.06
!

2000

...."

/""1

S 1500

.j:J

C
1000
II)

1

t:

a 500

~

0
-500

-0.08

-0.80

Inlet of the kicker magnet

Length(m)

~

Q)

2

II)

E

(

1000

2000

2:!

~~

~

3000

4000

50 o

0.04

~ 0.02~00Time (ns)

20

40

60

80

100

Moltage of power supply (kV)Fig. 5. Current waveforms at the outlet of the thyratronand inlet of the termination resistor.

Fig. 7. Dependence of the peak magnetic field on voltageof the power supply.

ment of the current and the magnetic field, respectively. The search coil is a one-turn coil 5 mm wide and
470 mm long. The diameter of the wire is 0.5 mm. Output voltages are measured with a high-voltage probe
and digital oscilloscope. The waveform of the magnetic
field is obtained by integrating the induced voltage atthe end of the search coil.
Figure 5 shows the current waveforms at the outlet of
the thyratron and inlet of the termination resistor. Reflection currents are observed immediately after falling
due to the mismatch of impedance between the PFN
and transmission cable. Figure 6 shows the waveformsof the induced voltage and the magnetic field in thecore gap at 100 kV. The rise time of the waveform isapproximately 104 ns, flat-top time is 922 ns. The risetime of the magnetic field becomes longer than the expected value (95 ns).
The dependence of the peak magnetic field on voltage of the power supply is shown in Fig. 7. The difference between the measured result and the calculated
result is less than ±3%.
We intend to perform further tests and study theultimate kick strength and amplitude stability.
References
1) T. Ohkawa et al.: Proc. EPAC2000, p.2113 (2000).

363

RIKEN Accel. Prog. Rep. 34 (2001)

Ferrite Evaluation Test for MUSES
Y. Chiba and K. Ohtomo
The ferrite core used for accelerator cavities has unfavorable features in that its loss factor (inverse of magnetic Q-value) rapidly increases with rf power level
and a "high loss effect" 1) occurs above the threshold power level. The high loss effect is characterized by a short period , less than a few ms, of normal
cavity voltage followed by a voltage decrease at theonset of rf excitation. During the high loss period,
the loss factor increases further and also the appearance of noise in the amplitude and phase of the cavity
voltage was reported. 1) These features govern the risein core temperature under high-voltage operation andlimit the maximum voltage sustained by a core; they
impose serious limitations in the design of a ferriteloaded cavity. To investigate these problems, a ferrite
test cavity 2,3) was constructed as part of the MUSES
project at RIKEN.
The accumulation cooler ring (ACR)4) in MUSES
uses a cavity frequency in the vicinity of 33 MHz.
Characteristics of a Ni-Zn ferrite sample, type V2Ffrom TDK Co. , Ltd., were measured at 33 MHz using
the test cavity. The core is a candidate for the ACR
cavity and has a size of 127 (inner diameter) x 203(outer diameter) x 25.4 (thickness) mm.
The measurement was carried out by varying the rf
input power at a fixed bias current. A pulse excitationof 20 ms duration with 5% duty was used. The data
were obtained at two positions on the time scale. The
first was at 0.5 ms after the rise in pulse excitation andthe second was at 16 ms after the rise. These corresponded to before and after the onset of the high loss
effect, respectively. Tuning and impedance matchingwere adjusted as accurately as possible for each data
point.
The effective value of relative permeability (p,),
stored energy density (Em) in the ferrite averaged over
the radius, power dissipation (Pt) in the entire volumeof the ring core, loss factor of the ferrite , and rf voltage (Vf) across the core thickness at the inner radius
were deduced from measured data on the basis of theradial-mode field distribution because the test cavity
was a radial-mode resonator with an open aperture at
the inner radius . For simplicity of analysis, a radially constant effective p, was assumed, although actualp, increases with the radius due to a 1/r decrease in
the bias magnetic field. Results for p, of 3.9, 8.2 and
15.4, which correspond to bias fields of 5530, 2270,
and 780 AT 1m, respectively, are given below. Figure 1
shows loss factor vs Em and Fig. 2, Pt vs Vf.
A decrease in voltage due to the high loss effect wasobserved on the oscilloscope in the range of rf power
level where separation of the two data lines was recognized in both figures. The threshold of the high364

0.012 ,---~--~-~--~-~-----.

0.010 .

... 0.008 ..

~J!! 0.006 .
II)
II)

.2
0 .004 . "..g::>: ----.,----.

0.002

0.000 ' - -_ _ _ _ _ _ _ _ _
0.0

0.5

1.0

1.5

~

_ _ __ _ _ . J

2.0

2.5

3.0

Em (Joules/cubic meter)

Fig. 1. Loss factor (inverse of magnetic Q-value) of theferrite at 33 MHz as a function of stored energy density (Em) in the ferrite. Square and plus marks show
the data obtained at 0.5 and 16 ms after the rise in rf
excitation, respectively.

~('CJ~ 1~ ~~=h~~~=~~~=&.

a:
2000
,

I

500 1'=8.2

500 1'=3.9

1000

1500

1000

Vf (O-Peak Volts)

Fig. 2. Total power loss (Pt) in the ferrite core at 33 MHz
as a function of the rf peak voltage (Vf) across the core
thickness at the inner radius. Square and plus marks
indicate the same as in Fig. 1.

loss effect in Em was estimated to be about 0.5 to
1.2 J 1m3 from Fig. 1. These figures are larger thanthose (0 .3 ± 0.1 J/m 3 ) given in Ref. 1. No appearanceof noise in the high loss region was observed in any
case. If the self heating of about 300 W in this corecan be cooled, the maximum usable voltage of the core
would be 700 to 900 volts (peak value), corresponding
to the p, range of 4 to 15 as shown in Fig. 2.
References
1) J. E. Griffin and G . Nicholls: IEEE Trans. Nucl. Sci .
26, 3965 (1979) .
2) K. Ohtomo and Y. Chiba: RIKEN Accel. Prog. Rep.
33, 251 (2000) .
3) K. Ohtomo et al.: Proc. EPAC2000, (2000), p.1987.
4) K. Ohtomo et al. : RIKEN Accel. Prog. Rep. 34, 357(2001).

RIKEN Accel. Prog. Rep. 34 (2001)

Helical Partial Snake Magnet for AGS
M. Okamura, T. Tominaka,*l T. Takeuchi,*2 and T. Katayama
For AGS synchrotron, Brookhaven National Laboratory has introduced a partial snake, which helps toovercome the imperfection resonances that appear during the acceleration of polarized protons. The existing
partial snake is a solenoid magnet located at the CI0
straight section of the AGS, and its field rises at thesame rate as that of the AGS main magnet. The longitudinal (Bz) component of the solenoidal partial snake
introduces linear coupling of the transverse coordinatesof the beam. This linear coupling appears on the single turn first-order transfer matrix of the AGS, andone of its effects is to realize additional intrinsic resonances which cause depolarization of the beam. To
achieve high polarization in RHIC, overcoming intrinsic resonance in the AGS is indispensable. In order toreduce the coupling caused by the solenoidal magnet,
an alternative partial snake which is a helical dipole
magnet has been proposed. The AGS partial helicalsnake would be composed of a single normal conducting helix with steering magnets on either side.
The designed 3D view is shown in Fig. 1. The effective magnetic length is 1500 mm and the bore is
150 x 150 mm in a square shape. Required magnetic
field strength for 9 degree spin rotation at G"( = 8.68
beam is 1.61 T. Here, G is called the 'anomalous magnetic moment' and is 1.7928 for protons. "( represents
the mass ratio in relativistic motion. Due to the useof a helical structure with a 360-degree rotation of themagnetic field, deflections of beam orbits will be canceled. However, considering the fringing fields in thereal magnet, there should be a correct rotation angle
which is less than 360 degrees. The optimized rotation angle of the iron pole determined using TOSCA
is 334.67 degrees and its length is 1393.2 mm. Consid-

ering the 3D-effect, the size, height and width of the
return yoke were determined not to exceed 1.5 T of the
field strength in the iron, except in the pole face region.
The yoke would be laminated in order to form such acomplex twisted structure. The assumed current is
198000 A turn for 1.61 T. The design parameters are
summarized in Table 1.
Figure 2 shows a comparison of the helical snakewith the existing solenoidal snake. In this graph, theintegrated longitudinal field along the beam trajectories are plotted for the both snakes. The operating G,of the AGS is from 4.7 to 47. Therefore, within the entire energy range of the AGS , the helical partial snake
induces much less longitudinal field and has a great
advantage in suppressing the coupling resonance. We
believe that the new snake system will be effective in
reducing depolarization in the AGS.

Table 1. Design Parameters.
Value

Parameter
Coils
CWTent density (Ncm 2)
Total CWTent (A turn)Power dissipation (kW)
Conductor size (mm)Diameter of hollow (mm)Total turns
Inductance (mH)
Number of turns

754
19800019
11.5 x 1l .5

7.5
1728

95
168 (14 x 12)

Yoke
Height(mm)Width(mm)Rotation angle (degrees)
Length(mm)Packing factor (%)

560
870
334.67
1393

99

5
,,

Snake I
4 H-Helical-----Solenoidal Snake I
,

3

,,

2
,,

Fig. 1. 3D view of helical partial snake.

o

,,

o

,,

,

,
,,

,,

,,

,

,
,,

,,

,,

,

,,

,
,,

,

,,

10

30

20

40

50

Gy
*1
*2

Hitachi, Ltd.
Center for Nuclear Study, Graduate School of Science, University of Tokyo

Fig. 2. Comparison of integrated longitudinal field.

365

366

VI. RADIATION MONITORINGRIKEN Accel. Prog. Rep. 34 (2001)

Routine Work for Radiation Safety in the Ring Cyclotron Facility
S. Fujita, S. Ito, H. Sakamoto,*l A. Uchiyama,*2 N. Hirao,*2 M. Kase, and Y. Uwamino
105

Here we report on the residual radioactivity andleakage radiation level of the Ring Cyclotron Facility.
Residual radioactivities in the Ring Cyclotron Facility were measured at various locations using ionizationchamber survey meters.
The measurements were performed after almost every beam experiment as well as during the routine overhaul period. The routine overhaul started immediately
after the experiment which was carried out with a polarized deuteron beam of 270 MeV in the E4 experimental vault from Aug. 1 to 3, 2000. The dose rates atthe deflectors of the RIKEN Ring Cyclotron and the
AVF Injector Cyclotron were measured from Aug. 22
to 23. These values were measured immediately before the maintenance of deflectors during the routine
annual overhaul, and Fig. 1 shows them over the lastfifteen years.
In the period from Oct. 1, 1999 to Sep. 30, 2000 ,dose rates were measured along the beam lines. The
spots a - z 1 marked by bullets in Fig. 2, are the places
where the dose rates exceeded 50 f..LSV Ih. Table 1 summarizes the observed dose rates and gives the dates

•
10

-

RINGI

AVF

4

103

..t:

en>::J..

102

10 1

year
Fig. 1. Variation of the dose rates at the deflectors of
the RIKEN Ring Cyclotron and the AVF Injector Cyclotron.

)(

y

xel·

X
yn

E4

~~:)

E3

E1

Fig. 2. Layout of the RIKEN Ring Cyclotron facility as of 2000. Measured locations of residual radioactivities along the beam lines are shown by bullets a- z.
*1*2

SRI Accelerator Service, Ltd.
Faculty of Science, Science University of Tokyo367

Table 1. Summary of the dose rates measured along
the beam lines using ionization-chamber survey meters.
The detection points a - z indicate the measured locations shown in Fig. 2.
Detection Measured
point dose rate

Date(~Sv/h)

a
b
c
d
e
f
g
h
j
k
m
n
0

p
q
r

s
t
u
v

w
X

Y
z

368

100
55
200
72
6000
2000
200
150
350
83
680
150
10000
350
300
450

SO
200
120
120
100
1800
3000
250
800
150

May 10, '00
May 10, '00
Aug 7, '00
Aug 7, '00
May 2, '00
May 2, '00
May 2, '00
May 2, '00
Jan 6, '00
Apr 14, '00
May 10, '00
May 10, '00
Apr 18, '00 .
Apr 14, '00
Jan 6, '00
Jan 6, '00
Ju1 25, '00
JuI 25, '00
Jan 25, '00
Jan 25, '00
Aug 1, '00
Nov 16,'99
Feb 15, '00
Oct 29,'99
May 2, '00
Nov 29,'99

Particle Energy Intensity Period(MeV/u)
100
100
270
270
270
d
270
d
270
d
270
d
135
0-18
100
Ca-40
100
Ca-40
100
0-18
100
0-18
100
135
d
d
135
He-4
135
He-4
135
N-14
135
N-14
135
N-14
135
135
N-14
N-14
135
210
p
270
d
d
70

Ca-40
Ca-40
d
d
d

(enA)
85
85
100
100
110
110
110
110
320
4400
85
85
4400
4400
320
320
800
800
5
5
800
700
800
660
110
82

(days)
3
3
2
2
2
2
2
2
6
10
3
3
10
10
6
6

1
2
2
1
2
2
7

when the measurements were performed. The maximum dose rate was 10 mSv /h at the target chamber ofthe RIKEN projectile-fragment separator, denoted bym in Fig. 2. Whenever we observed a high dose rate,
we roped off the area and posted a sign warning that it
was dangerous to remain in that area for a long periodof time.
We also continuously monitor the leakage radiationfrom the Ring Cyclotron Facility.
Having analyzed the collected data of leakage neutrons, we found that the radiation levels in the controlled area were much lower than the allowable dose
limit. The leakage of ,),-rays and neutrons was below
the detection limit of the environmental monitors. We
evaluated the radiation level at the boundary of the accelerator facility using the monitor which was installedin the computer room on the ground floor immediately
above a bending magnet which guided the beams fromthe ring cyclotron vault to the distribution corridor. As
a result, we obtained a radiation level of approximately
5 p,Sv / year which was much lower than the allowable
dose limit (1 mSv/year).

RIKEN Accel. Prog. Rep. 34 (2001)

Improvement of Drain System in the Ring Cyclotron Facility
S. Fujita, Y. Uwamino, S. Ito, H. Sakamoto,*l A. Uchiyama,*2 N. Hirao,*2 and M. Kase
The drain system of the Ring Cyclotron Facility has
been working steadily since 1986, and we have beenmonitoring the radioactive wastewater continuously.
The concentration of radionuclides in the wastewater

Fig. 1. Storage tank on the rooftop.

Fig. 3. New monitor panel board in the radiation safetycontrol office.

Fig. 2. New control panel board in front of the storage
tank.

*1

is measured using the method of evaporating a sampleof water until it is dry. During the time interval between the sampling and the measurement - that is,about 10 days - the wastewater is kept in a storagetank and the new wastewater is contained in anothertank. This time-consuming process has been necessary
since very-low-concentration limits were applied to theradioactive wastewater in the Japanese legislation forradiation safety.
The former drain system consisted of two I-m3 tanks
and a 1.5-m3 tank in the 2nd basement for storage, andtwo 2.5-m 3 tanks on the roof for dilution and automatic ,radioactivity measurement.
The volume of the wastewater, however, has augmented due to an increase in the number of users, andwe recently needed large storage tanks to meet the current demand. Hence we built two storage tanks withcapacities of 20 m 3 on the roof of the Ring Cyclotron
Facility this year, as shown in Fig. 1. The control andthe monitor panel boards for the entire drain systemwere replaced , and Figs. 2 and 3 show them, respectively.

SRI Accelerator Service, Ltd.

*2 Faculty of Science, Science University of Tokyo

369

370

VII. LIST OF PUBLICATIONS
1.

Accelerator
physics

development

andaccelerator

H. Okuno, T. Tominaka, S. Fujishima, A. Goto, and Y.
Yano: "Design study of the superconducting magnets for the injection system of the superconducting
ring cyclotron", Proc. 15th Int. Conf. on Magnet
Technology (MT15), Beijing, China, 1997-10, pp.
57-60 (1997).
H. Okuno, T. Tominaka, S. Fujishima, A. Goto, andY. Yano: "Design study of the injection and extraction systems for the RIKEN superconducting ring
cyclotron", Proc. 15th Int. Conf. on Cyclotrons andTheir Applications 98, Caen, France, 1998-06, editedby Eric Baron and Marcel Lieuvin, lOP Publishing,London, pp. 37- 40 (1998).
J .-W. Kim, A. Goto, T. Mitsumoto, T. Kawaguchi,
H. Okuno, T. Kubo, T. Tominaka, S. Fujishima,
K. Ikegami, N. Sakamoto, S. Yokouchi, K . Sugii,
J. Ohnishi, T . Morikawa, T. Wada, and Y . Yano:"Trim coil design for RIKEN superconducting ring
cyclotron", Proc. 15th Int. Conf. on Cyclotrons andTheir Applications 98, Caen, France, 1998-06, editedby Eric Baron and Marcel Lieuvin, lOP Publishing,London, pp. 207-210 (1998).
N. Sakamoto: "Design of the rf resonators for the newbooster ring cyclotrons in the RIKEN RI Beam Factory", Proc. 15th Int. Conf. on Cyclotrons and Their
Applications 98, Caen, France, 1998-06, edited by
Eric Baron and Marcel Lieuvin, lOP Publishing,London, pp. 223- 226 (1998).
J.-W. Kim, A. Goto, T. Mitsumoto, T. Kawaguchi,
H. Okuno, T. Kubo, T. Tominaka, S. Fujishima, K.
Ikegami, N. Sakamoto, T . Morikawa, K. Sugii, J.
Ohnishi, S. Yokouchi, T. Wada, and Y. Yano: "A
single-turn extraction study for the RIKEN superconducting ring cyclotron", Proc. 15th Int. Conf. on
Cyclotrons and Their Applications 98, Caen, France,
1998-06, edited by Eric Baron and Marcel Lieuvin,lOP Publishing, London, pp. 503- 506 (1998).
Y. Yano, A. Goto, and T . Katayama: "Overview
of RIKEN RI Beam Factory Project", Proc. 15th
Int. Conf. on Cyclotrons and Their Applications 98,
Caen, France, 1998-06, edited by Eric Baron andMarcel Lieuvin, lOP Publishing, London, pp. 696703 (1998).
Y. Goto: "Sensitivity to gluon polarization at RHIC",
Nucl. Phys. B (Proc. Suppl. ) 79, 588- 590 (1999).
S. Kohara, T. Nakagawa, O. Kamigaito, M. Fujimaki,
M. Kidera, T. Aihara, T. Ohki , H. Hasebe, H.
Yamauchi, M. Kase, A. Goto, and Y. Yano: "Status
report on RIKEN heavy ion linac", Proc. 12th Symp.
on Accelerator Science and Technology, Wako, 199910, edited by Y. Yano, RIKEN, pp. 168- 170 (1999).
M. Kidera, T. Nakagawa, K. Takahashi, S. Enomoto,T. Minami, M. Fujimaki, E. Ikezawa, O. Kamigaito,
M. Kase, A. Goto, and Y. Yano: "New method fortrace element analysis using the electron cyclotron
resonance ion source and heavy ion linac", Proc.
12th Symp. on Accelerator Science and Technology,
Wako, 1999-10, edited by Y. Yano, RIKEN, pp. 188190 (1999).
K. Sugii, K. Ikegami, S. Yokouchi, A. Goto, and Y.
Yano: "Vacuum system for the RIKEN superconducting ring cyclotron", Proc. 12th Symp. on Accelerator Science and Technology, Wako, 1999-10,
edited by Y. Yano, RIKEN, pp. 281- 283 (1999) .
K. Sugii, K. Ikegami, M. Ohtake, S. Yokouchi, A. Goto,
and Y. Yano: "Influence of external magnetic fieldon the performance of cold cathode gauges", Proc.
12th Symp. on Accelerator Science and Technology,
Wako, 1999-10, edited by Y. Yano, RIKEN, pp. 284286 (1999).
T. Kawaguchi, H. Okuno, A. Goto, J. Ohnishi, T .
Tominaka, T. Mitsumoto, and Y . Yano: "Superconducting sector magnets for the RIKEN superconducting ring cyclotron", Proc. 12th Symp. on Accelerator Science and Technology, Wako, 1999-10,
edited by Y. Yano, RIKEN , pp. 322- 324 (1999) .
N. Fukunishi, S. Ito, Y. Uwamino, and Y. Yano:"Shielding design of RIKEN RI Beam Factory",
Proc. 12th Symp. on Accelerator Science and Technology, Wako, 1999-10, edited by Y. Yano, RIKEN ,pp. 349- 351 (1999).
N. Fukunishi, K . Kusaka, H. Sakurai, T. Kubo, T .
Nagafuchi, H. Okuno, T. Mitsumoto, S. Fujishima,
M. Kase, A. Goto, and Y. Yano: "Design studies on beam transport system of RIKEN RI Beam
Factory", Proc. 12th Symp. on Accelerator Scienceand Technology, Wako, 1999-10, edited by Y. Yano,
RIKEN, pp. 438- 440 (1999).
M. Takanaka and T . Katayama: "Transverse instability due to the space charge during the electroncooling bunching of ion beams", Proc. 1999 Particle
Accelerator Conf., New York, USA, 1999-03, editedby A. Luccio and W. MacKay, Brookhaven National
Laboratory, New York, pp. 1719- 1721 (1999).
T. Kawaguchi, H. Okuno, A. Goto, T. Mitsumoto, T.
Tominaka, J. Ohnishi, and Y. Yano: "Developmentof sector magnets for the RIKEN superconducting
ring cyclotron", Teion Kougaku 34, 405- 413 (1999).
T . Kawaguchi, H. Okuno, A. Goto, T . Mitsumoto, T.
Tominaka, J. Ohnishi, and Y . Yano: "Developmentof sector magnets for the RIKEN superconducting
ring cyclotron", Teion Kougaku 34, 414- 423 (1999) .
S. Bhattacharjee, T . Nakagawa, and Y. Yano: "Particle confinement time in a plasma produced by shortpulse high-power microwaves" , Bull. Am. Phys. Soc.
45, 230- 231 (2000).
S. Bhattacharjee, H. Amemiya, and Y. Yano: "Mi-371

crowave breakdown of gas in a circular tube witha radius below the cut-off value", Bull. Am. Phys.
Soc., 45 , 369- 369 (2000).
S. Bhattacharjee and H. Amemiya: "Production ofpulsed microwave plasma in a tube with a radiusbelow the cut-off value", J . Phys. D 33, 1104- 1116
(2000).
Y. Kawamura, D. Li , R. Shlomo, T. Tanabe, andK. Toyoda: "Laser undulator radiation", Nucl. Instrum. Methods Phys. Res. A 445 , 241- 246 (2000).
V. Banerjee, A. Chakrabarti, A. Bandyopadhyay,
S. Chattopadhyay, A. Polley, T. Nakagawa, O.
Kamigaito, A. Goto, and Y. Yano: "Design of a
two-ion-source (2-IS) beam transport line for the
production of multi charged radioactive ion beams",
Nucl. Instrum. Methods Phys. Res. A 447, 345- 349(2000).
S. Bhattacharjee and H. Amemiya: "General properties of high power short pulse microwave plasmas", Proc. 17th Symp. on Plasma Processing,
Nagasaki, 2000-01 , edited by H. Sugai, Divisionof Plasma Electronics, Japan Soceity of Applied
Physics , Tokyo, pp. 61- 64 (2000).
M. Niimura, M . Lamoureux, A. Goto, and Y. Yano:"Dynamic simulations of the interchange instability, ion production, and electron heating processes inan electron cyclotron resonance ion source plasma" ,Rev. Sci. Instrum. 71 , 846- 849 (2000).
S. Bhattacharjee and H. Amemiya: "Pulsed microwave
plasma production in a conducting tube with a radius below cutoff" , Vacuum 58, 222- 232 (2000).
2.

Nuclear physics and nuclear instrumentation

K. Varga and Y. Suzuki: "Solution of few-body problems with the stochastic variational method 1. Central forces with zero orbital momentum", Comput.
Phys. Commun. 106, 157- 168 (1997).
F. Soramel, C. Signorini, L. Muller , Z. C. Li, A.
Andrighetto, Z. H. Liu , A. Yoshida, Y. Pu , T.
Fukuda, K. E. G. Lobner, K. Rudolph, C. Zotti,
and J. L. Sida: "Influence of break-up on fusion of
9,11 Be+ 209 Bi'', Perspectives in Heavy Ion Physics:
3rd Japan-Italy Joint Symposium '97, Padova, Italy,
1997-10, edited by C. Signorini, F. Soramel, andT. Kishida, World Scientific, Singapore, pp. 83- 91(1997).
T. Kikuchi, T. Motobayashi, N. Iwasa, Y. Ando, M.
Kurokawa, S. Moriya , H. Murakami, T. Nishio, J.Z. Ruan, S. Shirato, S. Shimoura, T. Uchibori, Y.
Yanagisawa, T. Kubo , H. Sakurai, T. Teranishi , Y.
Watanabe, M. Ishihara, M. Hirai, T. Nakamura, S.
Kubono, M. Gai, R. H. France III, K. 1. Hahn, T.
Delbar, P. Lipnik, and C. Michotte: "Experimental
determination of the E2 component in the Coulomb
dissociation of BB", Phys. Lett. B 391 , 261- 266(1997).

372

Y. Suzuki, J. Usukura, and K. Varga: "New description of orbital motion with arbitrary angular momenta" , J. Phys. B 31 , 31- 48 (1998).
G. Ryzhikh, J. Mitroy, and K. Varga: "The stabilityof the ground state for positronic sodium", J. Phys.
B 31 , L265- L271 (1998).
M. Oi, N. Onishi, N. Tajima, and T. Horibata: "Signature and angular momentum in 3d-cranked HFBstates" , Phys. Lett. B 418 , 1- 6 (1998).
T. Ohnishi, H. Sakai, H. Okamura, S. Ishida, H. Otsu,
N. Sakamoto, T . Uesaka, T. Wakasa, Y. Satou, T.
Fujita, and E. J. Stephenson: "Measurement of acomplete set of analyzing powers for deuteron elastic
scattering from 40Ca at 270 Me V and an investigation of tensor potentials", Phys. Lett. B 438 , 27- 34(1998).
M. R. Ahmady, V. Elias, and E. Kou: "Nonperturbative QCD contribution to gluon-gluon-'T}' vertex" ,Phys. Rev. D 57, 7034- 7036 (1998).
M. R. Ahmady, E. Kou , and A. Sugimoto: "Nonspectator contribution: A mechanism for inclusive
B ---7 X s'T}' and exclusive B ---7 K( *) 'T}' decays" , Phys.
Rev. D 58, 14015-1- 14015-5 (1998).
T. Ariga and K. Suda: "Gas flow simulation of a gas
cell of IGISOL", RIKEN Rev., No. 19, p . 13 (1998).
Y. Mochizuki, K. Takahashi, H.-Th. Janka, W.
Hillebrandt , and R. Diehl: ,,44Ti: its effective decayrate in young supernova remnants and its abundancein Cassiopeia A", Astron. Astrophys. 346, 831- 842(1999) . .
E. Ideguchi, X. Zhou , Y. Gono, S. Mitarai , T.
Morikawa, M. Kidera, H. Tsuchida, M. Shibata, H.
Watanabe, M. Miyake, A. Odahara, M. Oshima, Y.
Hatsukawa, S. Hamada, H. Iimura, M. Shibata, T.
Ishii, T . Kishida, and M. Ishihara: "A new high spinisomer in 146 Eu", Eur. Phys. J. A 6 , 387- 390 (1999).
S. N. Nakamura, K. Bartlett , G. A. Beer, D. R. Gill,
R. Hayano, T. Ito, M. Iwasaki, L. Lee, G. Mason, A.
Olin, H. Outa, M. Salomon, R. Seki, T. Taniguchi,
T. P. Terada, G. Trayling, Y. Yamashita, and S.
Yen: "Observation of kaonic hydrogen atom X-ray",Hyperfine Interact. 118, 45- 51 (1999).
C. Petrascu, S. Bianco, A. M. Bragadireanu, F.
L. Fabbri, C. Guaraldo, :M. Iliescu , T. M.
Ito, V. Lucherini, M. Bregant , E. Milotti, A .
Vacchi , E. Zavattini, M. Augsburger, D. Chatellard ,P. Knowles , F. Mulhauser , L. A. Schaller, L.
Schellenberg, H. Schneuwly, J.-P. Egger , D. Varidel,
W. H. Breunlich, M. Cargnelli, B. Gartner , R. King,
B. Lauss, J. Marton, J. Zmeskal, T. Ponta, S. N.
Nakamura, T. Koike, R. S. Hayano, M. Hori, T.
Ishikawa, T . Ishiwatari, M. Iwasaki, Y. Akaishi, G.
Beer, A. C. Sanderson, and R. Seki: "Disentangling
the K-complex of kaonic hydrogen with DEAR",
Hyperfine Interact. 118, 53- 57 (1999).
S. N. Nakamura, K. Nagamine, T. Matsuzaki, K.
Ishida, N. Kawamura, S. Sakamoto, M. Iwasaki ,M. Tanase, M. Kato, K. Kurosawa, H. Sugai, 1.
Watanabe, K. Kudoh, N. Takeda, and G. H. Eaton:"Measurement of the K.e IKa ratio for muon alphasticking X-rays in muon catalyzed d-t fusion at the
RIKEN-RAL Muon Facility" , Hyperfine Interact.
118, 209- 212 (1999).
T. Matsuzaki, K. Nagamine, K. Ishida, S. N.
Nakamura, N. Kawamura, M. Tanase, M. Kato, K.
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E. Zavattini, M. Augsburger, D. Chatellard,
P. Knowles, F. Mulhauser, L. A. Schaller, L.
Schellenberg, H. Schneuwly, J.-P. Egger, D. Varidel,
W. H. Breunlich, M. Cargnelli, B. Gartner, R. King,
B. Lauss, J. Marton, J. Zmeskal, T. Ponta, S.
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T. Matsuzaki, K. Nagamine, M. Tanase, M. Kato, K.
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K. Matsuta, T. Onishi, M. FUkuda, T. Minamisono,
M. Mihara, M. Sasaki, T. Yamaguchi, T. Miyake, K.
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Tsubota, T. Sumikawa, A. Kitagawa, M. Torikoshi,
M. Kanazawa, T. Nishio, S. Koda, T. Ohtsubo,
S. Fukuda, Y. Nojiri, S. Momota, A. Ozawa, K.
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S Hanna, J. R. Alonso, G. F. Krebs , T. J. M.
Symons, and K. Tanaka: "Spin polarization of j3emitting fragments in high energy heavy ions on Be
collisions", Hyperfine Interact. 120/121 , 713- 717(1999).
T. Kishida, Y. Gono , M. Shibata, H. Watanabe, T.
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T. Horibata, M. Oi, N. Onishi, and A. Ansari: "Erratum to "Band structures of 1820S studied by GCM
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N. Saito: "RHIC spin physics: Status of polarized collider and spin-flavor structure of the nucleon" , Nucl. .
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V. Nogach, S. B. Nurushev, A. 1. Pavlinov, A. N.
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Y. Kondo, Y. Nakada, M. Nakamura, H. D. Sato,
H. Okamura, H. Sakai, T. Wakasa, V. Baturine, A.
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A. A. Korsheninnikov , M. Golovkov , A. Ozawa, E.
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A. Ogloblin, 1. Tanihata, Zs. Fiilop , K. Kusaka, K.
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Y. Mochizuki: "The origin of neutron star glitches",
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Y. Mochizuki: ,,44Ti: its effective decay rate in young
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K. Kusaka, T. Sakai, and H. Toki: "Bethe-Salpeter
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H. Madokoro and M. Matsuzaki: "Relativistic andnon-relativistic mean field investigation of the superdeformed bands in 62Zn", Prog. Theor. Phys.
101 , 1027- 1041 (1999).
N. Dinh Dang and U. Garg: "Introduction to the proceedings on selected topics in nuclear collective excitations" , RIKEN Rev. , No. 23 , p. 1 (1999).
Y. Matsui:"Nucleon-trinucleon scattering with
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S. Bianco, A. M. Bragadireanu, F. L. Fabbri , C.
Guaraldo, M. Iliescu, T. M. Ito, V. Lucherini,
C. Petrascu, M. Bregant, E. Milotti, A. Vacchi ,E. Zavattini, M. Augsburger , D. Chatellard,
P. Knowles , F. Mulhauser, L. A. Schaller, L.
Schellenberg, H. Schneuwly, J.-P. Egger, D. Varidel ,W. H. Breunlich, M. Cargnelli , B. Gartner, R. King,
B. Lauss, J. Marton, J. Zmeskal, T. Ponta, S.
N. Nakamura, T. Koike , R. Hayano, M. Hori , T.
Ishikawa, T . Ishiwatari , M. Iwasaki , Y. Akaishi, G.
A. Beer, A. C. Sanderson, and R. Seki: "The DEAR
case", Riv. Nuovo Cimento 22 , 1- 45 (1999).
X. Zhou , E . Ideguchi , T. Kishida, M. Ishihara, H.
Tsuchida, Y. Gono , T. Morikawa, M. Shibata, H.
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Ideguchi , X. Zhou, A. Odahara, S. Kubono , J. H. Ha,
M. K. Cheoun, C. Lee, J. C. Kim, C. B. Moon, S. J.
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band in 155Gd", Eur. Phys. J. A 7, 11- 14 (2000).
T. Ohnishi, H. Sakai, H. Okamura, S. Ishida, H. Otsu,
N. Sakamoto, T. Uesaka, T. Wakasa, and Y. Satou:"Measurement of deuteron elastic scattering at Ed =270 Me V and a comparison with sudden approximation", Few Body Systems Supp!. 12: Few Body
Problems in Pysics '99, Kashiwa , 1999-08, edited by
S. Oryu, M. Kamimuna, and S. Ishikawa, Springer,
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H. Sakai, K. Sekiguchi, H. Kato, A. Tamii, T. Ohnishi,
K. Yako , S. Sakoda, Y. Maeda, M. Hatano, N.
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K. Sekiguchi , H. Sakai, and H. Okamura: "Measurement of cross sections and vector and tensor analyzing powers for d-p elastic scattering at Ed =270 MeV", Few Body Systems Supp!. 12: Few Body
Problems in Pysics '99, Kashiwa, 1999-08, edited by
S. Oryu, M. Kamimura, and S. Ishikawa, Springer ,Wien, pp. 474- 478 (2000).
H. Okamura: "Fast data acquisition system for the
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A. Ozawa, O. V. Bochkarev, L. Chulkov, D. CortinaGil , H. Geissel , M. Hellstrom, M. Ivanov, R. Janik,
K. Kimura, T. Kobayas hi , A. A. Korsheninnikov , G.
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V. Pribora, H. Simon, B. Sitar, P. Strmen, K.
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and K. Yoshida: "Prod uction cross-sections oflight neutron-rich nuclei from 40 Ar fragmentation atabout 1 GeV /nucleon" , Nucl. Phys. A 673 , 411- 422(2000).
L. Chulkov, O. V. Bochkarev, D. Cortina-Gil, H.
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Miinzenberg, F. Nickel , A. A. Ogloblin, A. Ozawa,
M. Pfiitzner, V. N. Privora, M. V. Rozhkov, H.
Simon, B. Sitar, P. Strmen, K . Summerer, T. Suzuki,
1. Tanihata, M. Winkler, and K. Yoshida: "Total
charge-changing cross sections for neutron-rich lightnuclei", Nucl. Phys. A 674, 330- 342 (2000).
N. Dinh Dang, K. Tanabe, and A. Arima: "Damping ofmultiphonon giant resonances", Nucl. Phys. A 675 ,
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R. Kanungo, I. Tanihata, Y. Ogawa, and A. Ozawa:"Halo structure in 19C: A Glauber model analysis" ,Nucl. Phys. A 677,171- 186 (2000).
K. Asahi: "Nuclear and fundamental physics with
spin-polarized nuclei", Nuclear Study 44, No.4, pp.
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S. N. Nakamura, K. Nagamine, T. Matsuzaki, K.
Ishida, N. Kawamura, Y. Matsuda, M. Tanase, M.
Kato, K. Kurosawa, H. Sugai, and G. H. Eaton:"The first observation of muon-to-alpha sticking Kj3
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H. Kurasawa and T. Suzuki: "Effects of the Dirac sea
on the giant monopole states", Phys. Lett. B 474,
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T. Nakatsukasa, N. R. Walet, and G. D. Dang: "Local harmonic approaches with approximate cranking
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X. Zhou, H. Tsuchida, Y. Gono, A. Odahara, E.
Ideguchi, T. Morikawa, M. Shibata, H. Watanabe,
M. Miyake, T. Tsutsumi, S. Motomura, T. Kishida,
S. Mitarai, and M. Ishihara: "Level structurein 143Nd", Phys. Rev. C 61, 014303-1- 014303-11(2000).
M. Tanifuji, S. Ishikawa, Y. Iseri, T. Vesaka, N.
Sakamoto, Y. Satou, K. Itoh, H. Sakai, A. Tamii,
T. Ohnishi, K. Sekiguchi, K. Yako, S. Sakoda, H.
Okamura, K. Suda, and T. Wakasa: "Reaction
mechanism and characteristics of T 20 in d+ 3He backward elastic scattering at intermediate energies",
Phys. Rev. C 61 , 024602-1-024602-8 (2000).
N. Dinh Dang, K. Eisenman, J. Seitz, and M.
Thoennessen: "Statistical analysis of the hot giant
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V. Y. Denisov and S. Yamaji: "Single- and doublephonon giant monopole resonances in a nonlinear
approach", Phys. Rev. C 61, 044318-1- 044318-9(2000).
N. Dinh Dang, T. Suzuki, and A. Arima: "Giant dipole
resonance in neutron-rich nuclei within the phonon
damping model", Phys. Rev. C 61 , 64304-1- 64304-2(2000) .
A. Ansari, N. Dinh Dang, and A. Arima: "Hot giant dipole resonance with thermal fluctuation corrections in the static path approximation", Phys.
Rev. C 62, 11302-1- 11302-4 (2000).
Y. M. Zhao, N. Yoshinaga, S. Yamaji , J. Q. Chen,
and A. Arima: "Nucleon-pair approximation of theshell model", Phys. Rev. C 62 , 014304-1- 014304-9(2000).
Y. M. Zhao, S. Yamaji, N. Yoshinaga, and A. Arima:"Nucleon-pair approximation of the nuclear collective motion", Phys. Rev. C 62, 014315-1- 014315-10(2000).
Y. M. Zhao, N. Yoshinaga, S. Yamaji, and A. Arima:"Validity of SD-pair truncation of the shell model",Phys. Rev. C 62, 014316-1- 014316-9 (2000).
N. Dinh Dang and A. Arima: "Extended renormalized random phase approximation", Phys. Rev. C
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K. Tanabe and N. Dinh Dang: "Exact form of the random phase approximation equation at finite temperature including the entropy effect", Phys. Rev. C 62,
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Y. M. Zhao, N. Yoshinaga, S. Yamaji, and A. Arima:"Relationship between fermion dynamical symmetric model Hamiltonian and nuclear collective motion", Phys. Rev. C 62 , 024322-1- 024322-6 (2000).
Y. Fujita, B. A. Brown, H. Ejiri, K. Katori, S.
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isovector, orbital, and spin contributions in M1
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J. Golak, H. Kamada, H. Witala, W. Glockle, J. KurosZolnierczuk, R. Skibinski, V. V. Kotlyar, K. Sagara,and H. Akiyoshi: "Faddeev calculations of protondeuteron radiative capture with exchange currents",
Phys. Rev. C 62, 054005-1- 054005-16 (2000).
H. Kurasawa and T. Suzuki: "Effects of the neutron
spin-orbit density on the nuclear charge density inrelativistic nuclear models"., Phys. Rev. C 62,543031- 54303-4 (2000).
R. Bieber, W. Glockle, J. Golak, M. N. Narakeh,
D. Hiiber, H. Huisman, N. Kalantar-Nayestanaki,
H. Kamada, J. G. Messchendorp, A. Nogga, H.
Sakai, N. Sakamoto, M. Seip, M. Volkerts, S. Y.
Van der werf, and H. Wit ala: "Three-nucleon force
and the Ay puzzle in intermediate energy p + d andp elastic scattering", Phys. Rev. Lett. 84, 606609 (2000).
A. Ozawa, T. Kobayashi , T. Suzuki, K. Yoshida, and
I. Tanihata: "New magic number, N = 16, near
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A. A. Korsheninnikov, M. Golovkov, A. Ozawa, E.
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A. Ogloblin, 1. Tanihata, Zs. Fiilop, K. Kusaka, K.
Morimoto, H. Otsu, H. Petrascu, and F. Tokanai:"Excited state of 7He and its unique structure",
Phys. Scr. T 788, 199-202 (2000).
Y. Mochizuki: "Half-lives of unstable nuclei producedin supernovae", Proc. 2nd Symp. on Science ofHadrons under Extreme Conditions, pp. 139- 141(2000).
T. Ichihara, Y. Watanabe, N. Hayashi, S. Sawada, S.
Yokkaichi, A. Taketani, Y. Goto, H. En'yo, and H.
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N. Dinh Dang: "Single and multiphonon resonances
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H. Kamada, T. Uesaka, W. Gloeckle, H. Sakai, S.
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T. Otsuka, N. Shimizu, S. Haruyama, M. Honma,
T. Mizusaki, A. Taketani, Y. Utsuno, and Y.
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Y. Watanabe, N. Shimizu, S. Haruyama, M. Honma,
T. Mizusaki, A. Taketani, Y. Utsuno, and T. Otsuka:"A workstation farm optimized for Monte Carlo
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3.

Atomic and solid-state physics

Y. Kobayashi, Y. Yoshida, K. Hayakawa, K. Yukihira,J. Nakamura, H Haesslein, S. Nasu, N. Inabe, Y.
Watanabe, A. Yoshida, M. Kase, A. Goto, Y. Yano,
E. Yagi, and F. Ambe: "In-beam Mossbauer spectrometers for materials science at RIKEN Accelerator Research Facility", Hyperfine Interact. C 3 , 273276 (1998).
V. V. Krishunamurthy, I. Watanabe, K. Nagamine, C.
Geibel, G. Sparn, and F. Steglich: "J..L +SR study ofheavy-fermion magnetism in Ce(Cul- xNixhGe2",
Hyperfine Interact. 120/121 , 607- 610 (1999).
J. Arai , T. Ishiguro, I. Watanabe, and K. Nagamine:"J..LSR study in La2-xSrxCul-yZny04 with x
1/8" , J. Low Temp. Phys. 117, 377- 382 (1999).
I. Watanabe,
M. Akoshima, Y. Koike, S.
Ohira, and K. Nagamine:"J..L+SR study on
Bi2Sr2Cal -x Y x(Cul-y Znyh08+8 around the holeconcentration of ~ per Cu", J. Low Temp. Phys.
117, 503- 507 (1999).
M. Akoshima, H. Noji, Y. Koike, T. Nishizaki, N.

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Kobayashi, I. Watanabe, and K. Nagamine: "Transport and J..LSR studies at pl'V~ in the Bi-2212 and Y123 phases", J. Low Temp. Phys. 117, 1163- 1167
(1999).
Y. Yamazaki: "Trapping, cooling and extraction of antiprotons, and the ASACUSA project", Non-neutral
Plasma Physics III, edited by John J. Bollinger, etal., American Institute of Physics, New York, pp.
48-58 (1999).
T. Ichioka, H. Higaki, M. Hori, N. Oshima, K. Kuroki,
A. Mohri, K. Komaki , and Y. Yamazaki: "Multiring trap as a reservoir of cooled antiprotons",
Non-neutral Plasma Physics III, edited by John J.
Bollinger, et al., American Institute of Physics, New
York, pp. 59- 64 (1999).
K. Awaga, N. Wada, I. Watanabe, and T. Inabe: "Unusual crystal structures and properties of nitronylnitrooxide radicals. Possible RVB states in moleculebased magnets", Philos. Trans. R. Soc. London. A
357, 2893- 2922 (1999).
I. Watanabe, M. Akoshima, Y. Koike, and K.
Nagamine: "Anomalous slowing down of Cu-spin
fluctuations observed by muon spin relaxation in the
Zn-substituted Bi2 Sr2Cal- xYx(Cul-yZnyh08+8
system around the hole concentration of ~ per Cu" ,Phys. Rev. B 60, R9955- R9958 (1999).
Y. Yamamoto , Y. Miyako, S. Kawarazaki, T. Takeuchi,
M. Ocio, P. Pari, J. Hammann, I. Watanabe,
K. Nishiyama, K. Shimomura, and K. Nagamine:"Low temperature properties of the heavy-fermion
Ce(Rul-xRhxh Sb at the magnetic-nonmagnetic
boundaries", Physica B 259/261, 66- 67 (1999).
V. V. Krishunamurthy , I. Watanabe, S. Ohira, K.
Nishiyama, K. Nagamine, M. Ishikawa, D. H.
Eom, and N. Takeda:"J.l+SR observation ofmagnetic ordering and non-Fermi liquid scalingin CeCoGe1.8Sh.2 ", Physica B 259/261, 374- 375(1999).
I. Watanabe and K. Nagamine: "J..LSR study of magnetically ordered state of the Zn-substituted La-Sr
system", Physica B 259/261 , 544-545 (1999).
I. Watanabe, M. Akoshima, Y. Koike , and K.
N agamine: "J.lSR study on the magnetic stateof the Zn-substituted Bi-2212 system", Physica B
259/261,557- 558 (1999).
W. Higemoto, K. Nishiyama, I. Watanabe, K.
Nagamine, A. Asamitsu, H. Kuwahara, and Y.
Tokura: "J..L+SR study on (Ndl-ySmy)o.sMn03" ,Physica B 259/261, 822- 823 (1999).
T. Nishimura and I. Shimamura: "Elastic scatteringof positrons from Ne, Ar, CH 4, and SiH 4", RIKEN
Rev. , No. 25, pp. 12- 13 (1999).
T. Iitaka and T. Ebisuzaki: "Efficient algorithm forcalculating two photon absorption spectra", RIKEN
Rev. , No. 25, pp. 84- 86 (1999).
H. Ikeda, N. Kuroda, Y. Tanaka, T. Kambara, K.
Yoshikawa, and R. Yoshizaki: "Magnetic properties

of Bi-2223 tapes irradiated by Xe ion" , Advances inSuperconductivity XII, Morioka, 1999-10, edited by
T. Yamashita and K. Tanabe, Springer, Tokyo, pp.
377- 378 (2000).
Y. Kanai, K. Iemura, and X.-M. Tong: "Production of
doubly excited He atoms in collisions of He 2+ ionswith alkaline-earth atoms", AlP Conf. Proc. , 500,
606- 615 (2000).
M. Hase, K. Ishioka, M. Kitajima, K. Ushida, and
S. Hishita: "Dephasing of coherent phonons by lattice defects in bismuth films", Appl. Phys. Lett. 76,
1258- 1260 (2000).
Y. Yamazaki, Y. Morishita, S. Ninomiya, and R.
Hutton: "Production of meta-stable multi-Rydberg
states: Resonant electron transfer into slow highly
charged ions" , Butsuri 55 , 430- 433 (2000).
E. Yagi: "Ion beam materials analysis-NRD (nuclear reaction detection method)", Ion beam materials analysis and materials modification, edited by
Fuminori Fujimoto and Kenichiro Komaki , Uchida
Rokakuho Publishing, Tokyo , pp. 37- 58 (2000).
N. Ishikawa, A. Iwase, Y. Chimi, O. Michikami, H.
Wakana, and T. Kambara: "Defect production induced by primary ionization in ion-irradiated oxide
superconductors" , J. Phys. Soc. Jpn. 69, 3563- 3575
(2000).
Y. Nagashima, T. Kurihara, F. Saito, Y. Itoh, A. Goto,
and T. Hyodo: "Stable, high-efficiency moderator
with tungsten mesh" , Jpn. J. Appl. Phys. 39, 53565357 (2000).
E. Yagi: "Application of accelerators in various
research fields: Solid state physics" , Kasokuki
Kougaku Handbook, edited by Y. Hirao, M. Odera,
H. Kamitsubo, and T. Fuketa, Nihon Genshiryoku
Sangyo Kaigi, Tokyo, pp. 235- 254 (2000).
A. Igarashi, 1. Shimamura, and N. Toshima: "Photo detachment cross sections of the positronium negativeion", New J. Phys. (Web) 2, 17.1- 17.14 (2000).
Y. Chimi, A. Iwase , N. Ishikawa, N. Kuroda, and T.
Kambara: "Radiation annealing induced by electronic excitation in iron", Nucl. Instrum. Methods
Phys. Res. B 164/165, 408- 414 (2000).
T. Kambara, Y. Kanai, T. M. Kojima, Y. Nakai, A.
Yoneda, K. Kageyama, and Y. Yamazaki: "Acoustic
emission from fast heavy-ion irradiation on solids",
Nucl. Instrum. Methods Phys. Res. B 164/165,
415- 419 (2000).
V. V. Krishunamurthy, 1. Watanabe, K. Nagamine, H.
Kuwahara, and Y. Tokura: "Critical spin dynamics
in Ndl- xSrxMn03 with x :;:::j 0.5", Phys. Rev. B 61,
4060- 4069 (2000).
M. Matsuda, K. Katsumata, R. S. Eccleston, S.
Brehmer, and H.-J. Mikeska: "Magnetic excitations
and exchange interactions in the spin-1/2 two-leg
ladder compound La6CaSCu24041 " , Phys. Rev. B
62, 8903- 8908 (2000).
N. Nishida, S. Kaneko, H. Sakata, H. Kajiwara,

M. Matsumoto, T. Mochiku, K. Hirata, and T.
Kambara: "Studies of boundary effects and symmetry of Cooper pairing in Bi2Sr2CaCu20x by LTSTS" , Physica B 284/288, 967- 968 (2000).
V. Krishnamurthy, K. Nagamine, 1. Watanabe, K.
Nishiyama, S. Ohira, M. Ishikawa, D. H. Eom,and T. Ishikawa:"N on-Fermi liquid behavior
in CeCoGe3 -x Six alloys" , Physica B 289, 47- 51(2000).
V. Krishnamurthy, 1. Watanabe, K. Nagamine, H.
Kuwahara, and Y. Tokura: "Spin dynamics in
Nd 1- xSr xMn03 with x = 0.5", Physica B 289, 5660 (2000).
S. Ohira, T. Ishida, T. Nogami, 1. Watanabe, F.
L. Pratt, and K. Nagamine: "J..LSR studies on
the organic radical magnet, 4-arylmethyleneaminoTEMPO", Physica B 289, 123- 127 (2000).
T. M. Briere, J. Jeong, T. P. Das, S. Ohira, and
K. N agamine: "Ab initio molecular orbital studies of the positive muon and muonium in 4arylmethyleneamino-TEMPO derivatives" , Physica
B 289, 128- 131 (2000).
J. Jeong, T. M. Briere, N. Sahoo, T. P. Das, S. Ohira,K. Nishiyama, and K. Nagamine: "Hartree-Fock investigation of muon trapping in the chemical ferromagnet 4-(p-chlorobenzylideneamino)-TEMPO" ,Physica B 289, 132- 136 (2000).
M. Matsuda, 1. Watanabe, and K. Nagamine: "Magnetic ordering in La2Cu205", Physica B 289, 161164 (2000).
M. Mekata, K. M. Kojima, 1. Watanabe, K. Nagamine,and H. Ikeda: "Magnetic ordering and fluctuationsin Ising spin nets Rb 2Co 1- xMg x F 4'" Physica B 289 ,
194-197 (2000) .
J. Arai, T. Ishiguro, M. Hirai, H. Shinmen, J.
Yokoyama, 1. Watanabe, and K. Nagamine: "Zninduced magnetic order detected by J..LSR aroundx =in La2-xSrxCUl-yZny04", Physica B 289,
347- 350 (2000).
F. L. Pratt, S. J. Blundell, Th. Jestadt, B. W.
Lovett, A. Husmann, 1. M. Marshall , W. Hayes,
A. Monkman, 1. Watanabe, K. Nagamine, R. E.
Martin, and A. B. Holmes: "J..LSR of conducting andnon-conducting polymers", Physica B 289,625- 630(2000).
Y. Miyake, K. ShimoInura, Y. Matsuda, R. J.
Scheuermann, P. Bakule, S. Makimura, P. Strasser,
S. N. Nakamura, K. Ishida, T. Matsuzaki, 1.
Watanabe, and K. Nagamine: "Construction of theexperimental set-up for ultra slow muon generationby thermal Mu ionization method at RIKEN-RAL",
Physica B 289 , 666- 669 (2000).
A. Fukaya, 1. Watanabe, S. Ohira, and K.
Nagamine: "Radio-frequency muon spin resonanceof Haldane-gap systems, Ni(C2HsN2hN02(CI04)
and NiC 20 4 2· (2-methylimidazole)" , Physica B
289/290 , 185- 188 (2000).

k

377

J. Kim, F. Saito, Y. Nagashima, T. Kurihara, A. Goto,
Y. Itoh, and T. Hyodo: "The design of a spinpolarized slow positron beam", Rad. Phys. Chern.
58, 759-762 (2000).
N. Suzuki, A. Takamori, J. Baba, J. Matsuda, T.
Hyodo, Y. Okamoto, and H. Miyagi: "Positron annihilation study of high impact polystyrene", Radiat.
Phys. Chern. 58 , 593- 596 (2000).
N. Suzuki, Y. Nagai, and T. Hyodo: "Can a newly
developed AMOC technique be applied to determine the para-positronium lifetime?", Radiat. Phys.
Chern. 58, 777- 780 (2000).
H. Torii , Y. Morishita, Y. Yamazaki, K. Komaki , K.
Kuroki, R. Hutton, K. Ishii, K. Ando, H. Masuda,
M. Sekiguchi, M. Hori, E. Widmann, and R. S.
Hayano: "Spectroscopy of high Rydberg states ofhighly charged ions and antiprotonic helium atoms",
RIKEN Rev., No. 31, pp. 30-33 (2000) .
Y. Iwai, S. Thuriez, Y. Kanai , H. Oyama, K. Ando,
R. Hutton, H. Masuda, K. Nishio, K. Komaki, andY. Yamazaki: "High-resolution soft X-ray measurements in slow Ne9 + ions transmitted through a
micro capillary" , RIKEN Rev., No. 31, pp. 34- 37(2000).
Y. Nakai, T. Kambara, K. Ando, H. Oyama, and Y.
Yamazaki: "Plan of multiple ionization experimentwith ultra fast TW-Iaser in RIKEN", RIKEN Rev.,
No. 31, pp. 45- 47 (2000).
M. Wada, I. Katayama, S. Okada, Y. Ishida, T.
Nakamura, Y. Nakai, T. M. Kojima, Y. Kanai, T.
Kambara, Y. Yamazaki, Y. Okada, K. Noda, H.
Kawakami, and S. Ohtani: "Slow or trapped RIbeams from projectile fragment separators and theirlaser spectroscopy", RIKEN Rev., No. 31, pp. 56- 58(2000).
Y. Kanai, D. Dumitriu, Y. Iwai, T. Kambara, M.
Kitajima, T. M. Kojima, A. Mohri , Y. Morishita,
Y. Nakai, N. Oshima, H. Oyama, M. Wada, and Y.
Yamazaki: "Present status of slow highly charged
ion facility at RIKEN", RIKEN Rev. , No. 31, pp.
62- 64 (2000).
N. Oshima, T. M. Kojima, D. Dumitriu, A. Mohri,
H. Oyama, T. Kambara, Y. Kanai , Y. Nakai, M.
Wada, and Y . Yamazaki: "A new positron accumulator with electron plasma" , RIKEN Rev., No. 31,
pp. 65-69 (2000).
T. M. Kojima, N. Oshima, D. Dumitriu, H. Oyama, A.
Mohri, and Y. Yamazaki: "An ion trap for cooling ·MCIs with cold positrons", RIKEN Rev. , No. 31 ,pp. 70- 73 (2000).
H. M. Shimizu, T . Ikeda, H. Kato, K. Kawai, H.
Miyasaka, T. Oku, W. Ootani, C. Otani, H. Sato,
Y. Takizawa, and H. Watanabe: "Development ofsuperconductor radiation detectors", RIKEN Rev. ,No. 31 , pp. 74- 80 (2000).
E. Yagi: "The study on the state of hydrogen dissolved
in metals by means of the channelling method",378

Zairyo to Kankyo 49 , 282-287 (2000).
4.

Radiochemistry, radiation chemistry, and radiation biology

K. Matsumoto: "Foliar uptake and translocation of radionuclides in plants", Data Base for Nuclear Base
Technology, Radiation Application Development Association, No. 160006 (1998).
Y. Einaga, O. Sato, T. Iyoda, Y. Kobayashi, F. Ambe,
K. Hashimoto, and A. Fujishima: "Characterization of cobalt iron cyanide by 57Fe Mossbauer spectroscopy", Hyperfine Interact. C 3, 236- 239 (1998) .
Y. Kobayashi, Y. Yoshida, A. Yoshida, Y. Watanabe,
N. Aoi, K. Hayakawa, K. Yukihira, S. Nasu, J.
Nakamura, and F. Ambe: "In-beam Mossbauer
spectroscopy for materials science at RIKEN accelerator research facility", Proc. Specialist Research
Meet. on Solid State Physics with Probes of Radiations and Nuclei, edited by S. Nasu, Y. Kawase ,and Y. Maeda, Research Reactor Institute, Kyoto
University, pp. 88-90 (1998).
Y. Einaga, O. Sato, T. Iyoda, Y. Kobayashi, F. Ambe ,K. Hashimoto, and A. Fujishima: "Characterization of cobalt-iron cyanide by 57Fe Mossbauer spectroscopy" , Proc. Specialist Research Meet. on Solid
State Physics with Probes of Radiations and Nuclei, edited by S. Nasu, Y. Kawase , and Y . Maeda,
Research Reactor Institute, Kyoto University, pp.
114- 11 7 (1998).
S. Enomoto and N. Takematsu: "Theoretical consideration on the distribution of rare earth elements invarious organs of rats and mice" , Biomed. Res. Trace
Elements 10, 53- 56 (1999).
S. Ambe: "Multitracer studies on the absorption ofradionuclides via plant roots", Data Base for N uclear Base Technology, Radiation Application Development Association, No. 160005 (1999) .
T. Arie: "Stidies on the foliar uptake of radionuclides
in the air and their translocation in soybean plant" ,Data Base for Nuclear Base Technology, Radiation
Application Development Association , No . 160013(1999).
T. Shinonaga: "Studies on the uptake of radionuclides
by various plants from soil and on the subcellular
distribution of radionuclides in plants", Data Basefor Nuclear Base Technology, Radiation Application
Development Association, No. 160014 (1999) .
C. H. Bae, T. Abe, H.-Y. Lee, D.-C. Kim, K.-S.
Min, K.-S. Choi, T. Matsuyama, T. Nakano, andS. Yoshida: "Characterization of albino tobaccos(Nieotiana tabaeum L.) derived from leaf bladesegments cultured in vitro", J. P lant Biotech. 1 ,101- 107 (1999).
T. Funayama, I. Narumi, M. Kikuchi, S. Kitayama, H.
Watanabe, and K. Yamamoto: "Identification anddisruption analysis of the TeeN gene in the extremelyradioresistant bacterium Deinococcus mdiodumns" ,Mutat. Res. 435 , 151- 161 (1999).
H. Wang, N. Takematsu, and S. Ambe: "Effects of soil
acidity on the uptake of trace elements in soybean
and tomato plants" , Appi. Radiat. Isot. 52, 803- 811(2000).
H. Tamano, E. Igasaki , S. Enomoto, N. Oku, N. Itoh,
T. Kimura, K. Tanaka, and A. Takeda: "Hepatic
zinc response via metallothionein induction after tumor transplantation", Biochem. Biophys. Res. Commun. 270, 1140- 1143 (2000).
K. Ushida, M. Hase, K. Ishioka, and M. Kitajima:"Use of coherent phonon spectroscopy as a probe
for distribution of defects in solids" , Nonlinear Opt.
26, 145- 152 (2000).
F. Saito, Y. Nagashima, T. Kurihara, 1. Fujiwara, R.
Iwata, N. Suzuki, Y. Itoh, A. Goto, and T. Hyodo:"Spot 18F positron source electro-deposited on agraphite rod", Nuci. Instrum. Methods Phys. Res.
A 450, 491-494 (2000).
T. Matsuyama, T. Abe, C.-H. Bae, Y. Takahashi,
R. Kiuchi , T. Nakano, T. Asami , and S. Yoshida:"Adaptation of Restriction Landmark Genomic
Scanning (RLGS) to plant genome analysis", Plant
Mol. BioI. Rep. 18, 331- 338 (2000).
C. H. Bae, T. Abe, N. Nagata, N. Fukunishi, T.
Matsuyama, T. Nakano, and S. Yoshida: "Characterization of a periclinal chimera variegated tabacco(Nicotiana tabacum L.) ", Plant Sci. 151 , 93- 101(2000).
F. Saito, N. Suzuki, Y . Itoh, A. Goto, 1. Fujiwara, T.
Kurihara, R. Iwata, Y. Nagashima, and T. Hyodo:"Automatic 18F positron source supply system fora monoenergetic positron beam", Rad. Phys. Chern.
58, 755- 757 (2000).
K. Ushida, M. Hase, K. Ishioka, and M. Kitajima:"Study on ion-irradiated materials as probed by coherent phonon spectroscopy", Radiat. Chern. , No.
70, pp. 26-30 (2000).
H. Suzuki, H. Kumagaya, K. Oohashi, S. Enomoto,and F. Ambe: "Uptake of 15 trace elements in arbuscular mycorrhizal marigold measured by the multitracer t echnique", Soil Sci. Plant Nutr. 46, 283- 289(2000).
5.

Material analysis

K. Kholmurodov, K. Yasuoka, T. Ebisuzaki, and B.
Smith: "Thning DL_POLY for vector computers",
HPC Profile, No. 24, pp. 10-11 (1999).
J. Kawai , K. Hayashi, and K. Maeda: "EXEFS", Adv.

X-ray Anal. 42 , 83- 90 (2000).
H. Hamanaka, T. Hasegawa, K. Hasegawa, K. Maeda,
and S. Yumoto: "PIXE analysis of Al compounds
using a wavelength-dispersive spectrometer with
PSPC(3)" , Report of Research Center of Ion BeamTechnology Hosei University, No. SuppI.18, pp. 139140 (2000).
J. Kawai, Y. Mizutani, T. Sugimura, M. Sai, T.
Higuchi, Y. Harada, Y. Ishiwata, A. Fukushima, M.
Fujisawa, M. Watanabe, K. Maeda, S. Shin, and
Y. Gohshi: "High resolution soft X-ray absorption
spectroscopy for the chemical state analysis of Mn" ,Spectrochim. Acta B 55 , 1385- 1395 (2000).
6.

RIKEN-BNL Collaboration on Spin Physics Program

K. Itakura and S. Maedan: "Effects of topology on thelight front", Nuci. Phys. A 670, 76c- 79c (2000).
D. Boer, R. Jakob, and P. J. Mulders: "Angular dependences in electroweak semi-inclusive leptoproduction", Nuci. Phys. B 564, 471- 485 (2000).
D. Boer and P. J. Mulders: "Color gauge invariance inthe Drell-Yan process", Nuci. Phys. B 569 , 505- 526(2000).
K. Itakura and S. Maedan: "Dynamical chiral symmetry breaking on the light front: DLCQ approach",Phys. Rev. D 61, 045009-1- 045009-18 (2000).
D. T. Son and M. A. Stephanov: "Inverse meson massordering in the color-flavor-locking phase of highdensity QCD", Phys. Rev. D 61, 074012-1- 074012-8(2000).
K. Itakura and S. Maedan: "Dynamical chiral symmentry breaking on the light front II: The NambuJona-Lasinio model", Phys. Rev. D 62 , 15016-115016-19 (2000).
K. Suzuki, A. Hayashigaki, K. Itakura, J. Alam, andT. Hatsuda: "Validity of the color dopole approximation for diffractive production of heavy quarkonium", Phys. Rev. D 62 , 031501-1- 031501-4 (2000).
D. Boer: "Double transverse spin asymmetries in vector boson production", Phys. Rev. D 62, 094029-1094029-9 (2000).
D. T. Son: "Hydrodynamics of nuclear matter in thechirallimit" , Phys. Rev. Lett. 84, 3771- 3774 (2000).
D. T. Son and M. A. Stephanov: "QCD at finite isospin
density", Phys. Rev. Lett. 86, 592- 595 (2000).
D. Boer: "Transverse polarization distribution andfragmentation functions" , RIKEN Rev. , No. 28, pp.
26- 30 (2000).

379

VIII. LIST OF PREPRINTS2000

RIKEN-AF-NP
338 T. Suzuki, R. Kanungo, O. Bochkarev, L. Chulkov, D. Cortina, M. Fukuda, H. Geissel, M. Hellstrom,

M. Ivanov, R. Janik, K. Kimura, T. Kobayashi , A. A. Korsheninnikov, G. Munzenberg, F. Nickel , A. A.
Ogloblin, A. Ozawa, M. Pfiitzner, V. Pribora, and H. Simon: "Nuclear radii of 17, 19 B and 14Be"
339

R . Kanungo, 1. Tanihata, and C. Samanta: "Soft dipole resonance in 11 Li"

340

K. Sugawara-Tanabe, S. Yamaji, and A. Arima: "The pseudospin symmetry in the Dirac equatin with
deformed potential"

341

T. Suzuki: "A few topics on giant resonance states"

342 Y. Goto, N. Hayashi , M. Hirai, H. Horikawa, S. Kumano, M. Miyama, T. Morii, N. Saito, T.-A. Shibata, E.

Taniguchi, and T. Yamanishi: "Polarized parton distribution functions in the nucleon"
343 Y. M. Zhao, R. F. Casten, and A. Arima: "The NpNn scheme for heavy odd-A and doubly odd nuclei"
344 Y. M. Zhao, R. F. Casten, and A. Arima: "Effective valence proton numbers for nuclei near the Z = 64

subshell"345

N. Itagaki, S. Okabe, and K. Ikeda: "Important role of the spin-orbit interaction in forming the 1/2 + orbital
structure in Be isotopes"

346

N. Dinh Dang and A. Arima: "Extended renormalized random phase approximation"

347 H. Iwasaki, T. Motobayashi , H. Akiyoshi, Y. Ando, N. Fukuda, H. Fujiwara, Zs. FUlop, K. 1. Hahn, Y.

Higurashi, M. Hirai, 1. Hisanaga, N. Iwasa, T. Kijima, T. Minemura, T. Nakamura, M. Notani, S. Ozawa, H.
Sakurai, S. Shimoura, S. Takeuchi , T. Teranishi, Y. Yanagisawa, and M. Ishihara: "Quadrupole deformationof 12Be studied by proton inelastic scattering"
348 S. Ishimoto, T. Kobayashi, K. Morimoto, 1. Nomura, S. Suzuki, Y. Takahashi, 1. Tanihata, and T. Tsuru:"A windowless solid hydrogen target"
349 N. Dinh Dang, V. Kim. Au, and A. Arima: "Electromagnetic cross sections of double giant dipole resonancesin 136Xe and 208Pb within the phonon damping model"
350

A. Ozawa, T. Kobayashi , T. Suzuki, K. Yoshida, and 1. Tanihata: "A new magic number, N = 16, near to
the neutron drip-line"

351

A. Ozawa, O. Bochkarev, L. Chulkov, D. Cotia, H. Geissel, M. Helstrom, M. Ivanov, R. Janik, K. Kimura,
T. Kobayashi, A. A. Korsheninnikov, G. Munzenberg, F. Nickel, A. A. Ogloblin, M. Pfiitzner, V. Pribora, H.
Simon, B. Sitar, P. Strmen, K. Siimmerer, T. Suzuki, 1. Tanihata, M. Winkler , and K. Yoshida: "Production ·cross-sections of light neutron-rich nuclei from 40 Ar fragmentation at about 1 GeV jnucleon"

352

R. Kanungo, 1. Tanihata, Y. Ogawa, H. Toki, and A. Ozawa: "Halo structure in 19C: Aglauber model
analysis"353 H. Kurasawa and T. Suzuki: "Effects of the neutron spin-orbit density on nuclear charge density in rela-tivistic models"
354 S. Ishimoto, T. Kobayashi , K. Morimoto, 1. Nomura, S. Suzuki, Y. Takahashi, 1. Tanihata, and T. Tsuru:"Topological modes of solidification in liquids with a confined geometry"

380355 S.-G. Zhou, J. Meng, and S. Yamaji: "Relativistic mean field description of nitrogen isotopes"
356 N. Dinh Dang: "Description of single- and multiple-phonon giant dipole resonances within the phonon
damping model"
357 H. Iwasaki, T. Motobayashi, H. Akiyoshi, Y. Ando, N. Fukuda, H. Fujiwara, Zs. Fiilop, K. I. Hahn, Y.
Higurashi, M. Hirai, I. Hisanaga, N. Iwasa, T. Kijima, A. Mengoni, T. Minemura, T. Nakamura, M. Notani,S. Ozawa, H. Sagawa, H. Sakurai, S. Shimoura, S. Takeuchi, T. Teranishi, Y. Yanagisawa, and M. Ishihara:"Low lying intruder I-state in 12Be and the melting of the N = 8 shell closure"358 H. Madokoro, J. Meng, M. Matsuzaki, and S. Yamaji: "Relativistic mean field description for the shears
band mechanism in 84 Rb"
359 N. Saito: "Polarized parton distribution functions in the nucleon"
360 G. Bunce, N. Saito, J. Soffer, and W. Vogelsong: "Prospects for spin physics at RHIC"
361 N. Dinh Dang, A. Ansari, and A. Arima: "Angular-momentum effect on the width of hot giant dipole
resonance within the phonon damping model"
362 A. Ansari, N. Dinh Dang, and A. Arima: "Thermal shape and orientation fluctuation corrections for the
hot giant dipole resonance within the static path approximation"
363 Y. M. Zhao and A. Arima: "On predominance of 0+ ground states in even-even many-body system using
random two-body interactions: Single-j cases"
364 H. Sagawa, T. Suzuki, H. Iwasaki, and M. Ishihara: "Low energy dipole strength in light drip line nuclei"
365 K. Yoneda, H. Sakurai, T. Gomi, T. Motobayashi, N. Aoi, N. Fukuda, U. Futakami, Z. Gacsi, Y. Higurashi,
N. Imai, N. Iwasa, H. Iwasaki, T. Kubo, M. Kunibu, M. Kurokawa, Z. Liu, T. Minemura, A. Saito, M.
Serata, S. Shimoura, S. Takeuchi, Y. X. Watanabe, K. Yamada, Y. Yanagisawa, K. Yogo, A. Yoshida, and
M. Ishihara: "Large deformation of the neutron-rich isotope 34Mg from in-beam ,-ray spectroscopy using
RI beam fragmentation"
366 Y. Goto: "Sensitivities of the gluon polarization measurement at PHENIX"
367 K. Kurita: "Study of the spin structure of the nucleon with RHIC-PHENIX"
368 Y. M. Zhao, R. F. Casten, and A. Arima: "Systematics of nuclear deformation for large regions"
369 H. Kumagai, A. Ozawa, N. Fukuda, K. Siimmerer, and I. Tanihata: "Delay-line PPAC to high-energy lightions"
370 A. Arima, W. Bentz, T. Suzuki, and T. Suzuki: "Delta-hole interaction in nuclei and the Gamow-Teller
strength in 90Nb*"
371 K. Asahi, K. Sakai, H. Ogawa, H. Miyoshi, K. Yogo, A. Goto, T. Suga, H. Ueno, Y. Kobayashi , A. Yoshimi,
T. Kubo, Y. X. Watanabe, H. Imai, K. Yoneda, N. Fukuda, N. Aoi, M. Ishihara, W.-D. Schmidt-Ott,
G. Neyens, and S. Teughels: "Electromagnetic moments of neutron-rich nuclei measured with polarizedradioactive ion beams"
372 T. Motobayashi: "Nuclear astrophysics experiments with intermediate-energy radioactive ion beams"
373 I. Tanihata: "Nuclear radii and change in shell structure a halo driven new magic number N = 16"374 N. Dinh Dang, V. Kim. Au, T. Suzuki, and A. Arima: "Pygmy and giant dipole resonances in neutron-richnuclei within quasiparticle representation of phonon damping model"

381

375 M. Ishihara: "In-beam gamma-ray spectroscopy with RIB on very neutron-rich nuclei"
376 A. Ozawa, O. Bochkarev, L. Chulkov, D. Cortina, H. Geissel, M. Hellstrom, M. Ivanov, R. Janik, K. Kimura,
T. Kobayashi, A. A. Korsheninnikov, G. Munzenberg, F. Nickel, Y. Ogawa, A. A. Ogloblin, M. Pfiitzner,
V. Pribora, H. Simon, B. Sitar, P. Strmen, K. Siimmerer, T. Suzuki, 1. Tanihata, M. Winkler, and K.
Yoshida: "Measuremets of interaction cross-sections for light neutron-rich nuclei at relativistic energies anddetermination of effective matter radii"
377 N. Dinh Dang, T. Suzuki, and A. Arima: "Description of Gamow-Teller resonance within phonon damping
model"
378 M. Hirai, H. Kobayashi , and M. Miyama: "Determination of polarized parton distribution functions"
379 M. Petrascu, 1. Tanihata, K. Morimoto, T. Kobayashi, K. Katori, 1. Cruceru, M. Giurgiu, A. Isbasescu,
H. Petrascu, R. Ruscu, M. Chiba, S. Nishimura, A. Ozawa, T. Suda, K. Yoshida, C. Bordeanu, and A.
Tudorica: "Neutron pair pre-emission in the fusion of 11 Li halo nuclei with Si targets"
380 N. Dinh Dang and A. Arima: "Phonon damping model using random-phase-approximation operators"

RIKEN-AF-NC
17 Y. K. Batygin: "Particle-in-cell code BEAMPATH for beam dynamics simulations with space charge"
18 P. Zenkevich, T. Katayama, and A. Sidorin: "Problems of ion beam stability for MUSES storage rings"
19 A. Sidorin and I. Mesh: "Ion bunch stability in the double storage ring"
20 E. Syresin and T. Tanabe: "A proposal and simulations of a DSR electron cooling system"
21 A. Siminov, A. Sidorin, E. Syresin, I. Meshkov, T. Tanabe, and T. Katayama: "Computer simulation of
ECOOL and IBS process in ACR and DSR using BETACOOL program"
22 T. Katayama and D. Koshkarev: "New injection scheme for accumulator cooler ring"
23 D. Koshkarev: "Electron cooling and intrabeam scattering"
24 G. Shirkov, Y. Alexandrov, V. Presendorf, V. Shevtsov, R. Komisarov, M. Koryovkina, E. Shirkova, O.
Stekalovsky, N. Tokareva, A. Tuzikov, V. Vatulin, E. Vasina, V. Fomin, A. Anisimov, R. Veselov, A.
Golubev , S. Grushin, V. Povyshev, A. Sadovoi, and E. Don: "Physical and numerical basement of ECR
plasma simulation with particle-in-cell model"
25 A. Sidorin, P. Zenkevich, A. Bolshakov, and T , Katayama: "Optimization of intense ion beam parameterson ACR by use of the electron cooling system"382

IX. PAPERS PRESENTED AT MEETINGS
1.

Accelerator
physics

development

andaccelerator

T. Uesaka, T. Wakui, T. Ohnishi, H. Okamura, Y.
Satou, S. Ishida, N. Sakamoto, H. Otsu, T. Wakasa,
T. Nonaka, G. Yokoyama, K. Itoh, K. Sekiguchi,
S. Haruyama, T. Ikeda, M. Wakasugi, H. Sakai,
and Y. Yano: "Polarized 3He project at RIKEN" ,7th RCNP Int. Workshop on Polarized 3He Beams
and Gas Targets and Their Application, Kobe, Jan.
(1996).
S. Watanabe and T. Katayama: "Power supply system
for the RIKEN-MUSES project", 6th European Particle Accelerator Conf. (EPAC '98), (MSL), Stockholm, Sweden, June (1998).
T. Kawaguchi , H. Okuno, A. Goto, T. Mitsumoto, T.
Kubo, T. Tominaka, J.-W. Kim, K. Ikegami, and Y.
Yano: "Design of the sector magnets for the RIKEN
superconducting ring cyclotron", 15th Int. Conf. on
Cyclotrons and Their Applications (Cyclotrons '98),(GANIL), Caen, France, June (1998).
T . Kawaguchi, H. Okuno, A. Goto, T. Mitsumoto, T.
Tominaka' and Y. Yano: "Design of structure andquench-stability of sector magnets for RIKEN superconducting ring cyclotron", Applied Superconductivity 98, (LBL), Parm Springs, USA , Sept. (1998).
M. Takanaka and T. Katayama: "Transverse instability due to the space charge during the electroncooling bunching of ion beams" , 1999 Particle Accelerator Conf., (Brookhaven National Laboratory),
New York, USA, Mar. (1999).
T. Kurita, T. Nakagawa, T . Kawaguchi, and S. M. Lee:
"Design of electron cyclotron resonance ion source
using liquid-helium-free superconducting solenoid
coils", 8th Int. Conf. on Ion Sources (ICIS '99),(Kyoto University), Kyoto, Sept. (1999).
T. Hirumachi, T. Tominaka, T. Kubo, H. Sakurai, T.
Nagahuchi, K. Kusaka, M. Okamura, T. Fujioka,
T. Tsuchihashi, O. Osaki, T. Senba, and S. Suzuki:"Design of a superferric quadrupole magnet for the
RIKEN RI-Beam Factory project", 16th Int. Conf.
on Magnet Technology (MT16), (National High
Magnetic Field Laboratory), Ponte Vedre Beach,
USA, Sept. (1999).
N. Sakamoto: "Model test of the RIKEN-IRC main
resonator", 12th Symp. on Accelerator Science andTechnology, Wako, Oct. (1999).
N. Sakamoto: "Design of the RIKEN-SRC RF systern", 12th Symp. on Accelerator Science and Technology, Wako, Oct. (1999).
S. Kohara, O. Kamigaito, M. Kase, E. Ikezawa, Y.
Miyazawa, T. Chiba, and A. Goto: "Model test ofa resonator for flat-top acceleration system in the
RIKEN AVF cyclotron", 12th Symp. on Accelerator
Science and Technology, Wako, Oct. (1999).

T. Tanabe, T. Rizawa, K. Ohtomo, T . Katayama, E.
Syresin, A. Sidorin, and I. Meshkov: "Electron coolers for the MUSES project", 12th Symp. on Accelerator Science and Technology, Wako, Oct. (1999).
S. Bhattacharjee and H. Amemiya: "General properties of high power short pulse microwave plasmas", 17th Symp. on P lasma Processing, (The Association of Super-advanced Electronics Technologies(ASET)), Nagasaki, Jan. (2000).
A. Goto and Y. Yano: "Construction of the superconducting ring cyclotron for the RIKEN RI-Beam
Factory", 1st Workshop on Future P lan for Ion
Beam Application at JEARI-Takasaki, Takasaki,
Feb. (2000).
T. Takeuchi, T. Katayama, T. Nakagawa, M.
Okamura, K. Yano, B. Sharkov, S. Kondrashev,
and A. Shumshurov: "Laser ion source for RIKEN
MUSES project", 7th European Particle Accelerator
Conf. (EPAC2000), Vienna, Austria, June (2000).
T. Takeuchi, T. Katayama, T. Nakagawa, M.
Okamura, K. Yano, B. Sharkov, and S. Kondrashev:"Laser ion source f6r RIKEN MUSES project", 7thEuropean Particle Accelerator Conf. (EPAC2000),
Vienna, Austria, June (2000).
K. Ohtomo, N. Inabe, T. Katayama, T. Tanabe, andM. Wakasugi: "New lattice design of Accumulator
Cooler Ring for MUSES" , 7th European Particle Accelerator Conf. (EPAC2000), Vienna, Austria, June
(2000).
K. Ohtomo, Y. Chiba, T . Rizawa, and M. Wakasugi:"Ferrite evaluation test for MUSES", 7th European Particle Accelerator Conf. (EPAC2000), Vienna, Austria, June (2000).
T. Rizawa, T. Katayama, T. Tanabe, S. Takama, andA. Yamashita: "Design study of the ACR electroncooler for RIBF" , 7th European Particle Accelerator
Conf. (EPAC2000), Vienna, Austria, June (2000).
T. Tanabe, T. Masuoka, and M. Kase: "Preliminary
design of RIBF control system using CORBA and
RTOS" , 7th European Particle Accelerator Conf.
(EPAC2000), Vienna, Austria, June (2000).
S. Bhattacharjee: "Interpulse plasmas of high power
short pulse microwaves", 27th IEEE Int. Conf. on
Plasma Science (ICOPS 2000), New Orleans, USA,
June (2000).
H . . Hasebe, E. Ikezawa, Y. Miyazawa, M. Hemmi,
T. Aihara, T . Ohki, and H. Yamauchi: "Development of long-life carbon-foil by flashlight irradiation
method", 24th Linear Accelerator Meet. in Japan,(Hokkaido University), Sapporo, July (2000).
A. Goto: "Beam dynamics in cyclotrons", Accelerator School 2000, (BATAN), Yogyakarta, Indonesia,
Sept. (2000).

383

2.

Nuclear physics and nuclear instrumentation

Y. Gono: "In-beam gamma-ray spectroscopy", Int.
Workshop on JHF Science (JHF98), (KEK),
Tsukuba, Mar. (1998).
Y. Gono: "A windowless gas target for secondary
beam production", 19th World Conf. of INTDS ,Nuclear Targets Preparation, Characterization andUse, (Oak Ridge National Laboratory) , Oak Ridge,
USA , Oct. (1998).
A. Goto, K. Sakai, T. Suzuki, K. Yo go , K. Asahi,
H. Ogawa, A. Yoshimi , M. Nagakura, T. Suga, M.
Utsuro, and M. Hino: "Measurement of energy distribution in spallation neutron source for Sisythus
UCN production method", 1999 Fall Meet. of Physical Society of Japan, Matsue, Jan. (1999).
K. Morimoto, F. Tokanai, M. Nishimura, and 1.
Tanihata: "Development of beam monitor using
scintillating fiber", 54th Ann. Meet. of Physical Society of Japan, Higashihiroshima, Mar. (1999).
N. Dinh Dang and U. Garg: "Introduction to theproceedings on Selected Topics in Nuclear Collective Excitations", RIKEN Symp. and Workshop on
Selected Topics in Nuclear Collective Excitations ,Wako, Mar. (1999).
N. Dinh Dang, K. Tanabe, and A. Arima: "Microscopic description of the hot giant dipole resonance" ,RIKEN Symp. and Workshop on Selected Topics in
Nuclear Collective Excitations, Wako, Mar. (1999).
N. Dinh Dang, K. Tanabe , and A. Arima: "Damping of
giant dipole resonance as a probe into the order-tochaos transition in hot nuclei", RIKEN Symp. andWorkshop on Selected Topics in Nuclear Collective
Excitations, Wako, Mar. (1999) . .
K. Asahi , H. Ogawa, K. Sakai, A. Yoshimi, M. Tsuda,
Y. Uchiyama, T. Suzuki, K. Suzuki, N. Kurokawa,
M. Adachi, A. Yoshida, S. Fukuda, M. Notani, T.
Kubo , H. Okuno, H. Sato, N. Fukunishi, N. Aoi,
K. Yoneda, H. Iwasaki, N. Fukuda, M. Ishihara,
H. Izumi, H. Ueno, T. Shimoda, S. Tanimoto,
N. Takahashi, H. Miyatake, W. D. Schmidt-Ott,and M. Schoefer: "Nuclear moments measurementswith polarized radioactive beams", 4th Int. Workshop on Laser Spectroscopy on Beams of Radioactive Nuclei, (Adam Mickiewicz University), Poznan,
Poland, May (1999).
T. Suda: "Photodisintegration of few-nucleon systerns", Nuclear Science Seminar, (U niversity ofTokyo) , Tokyo, May (1999) .
T. N akatsukasa: "Selfconsistent determination of collective coordinates" , Nuclear Theory Seminar at Niigata University, Niigata, May (1999).
T. N akatsukasa: "Selfconsistent determination of collective coordinates", Seminar at Nuclear Theory
Group of University of Tokyo, Tokyo, May (1999).
T. N akatsukasa: "Selfconsistent determination of collective coordinates", Nuclear Theory Colloquium at

384

Kyoto University, Kyoto, June (1999).
T . Nakatsukasa: "Selfconsistent determination of collective subspace", Nuclear Theory Seminar at Tokyo
Metropolitan University, Hachioji, June (1999).
Y. Mochizuki: "Exotic nuclear rod model for the origin of neutron star glitches", Seminar at National
Astronomy Observatory, Mitaka, June (1999).
T. Nakatsukasa: "Determination of collective coordinates for low-energy collective motion", Nuclear
Theory Seminar at Chiba University, Chiba, July
(1999).
H. Sakai, K. Sekiguchi, H. Kato, A. Tamii, T. Ohnishi,
K. Yako, S. Sakoda, Y. Maeda, M. Hatano, N.
Sakamoto, T. Uesaka, Y. Satou, H. Okamura, K.
Suda, and T. Wakasa: "Precise measurement of d p
elastic scattering at 270 MeV" , Asia Pacific Conf. on
Few-Body Problems in Physics (APFB 99) , (Science
University of Tokyo) , Kashiwa, Aug. (1999).
T. Ohnishi, H. Sakai, H. Okamura, S. Ishida, H. Otsu,
N. Sakamoto, T. Uesaka, T. Wakasa, Y. Satou, andT. Nonaka: "Measurement of deuteron elastic scattering at Ed = 270 MeV and a comparison withsudden approximation", Asia Pacific Conf. on FewBody Problems in Physics (APFB 99), (Science University of Tokyo), Kashiwa, Aug. (1999).
Y. Mochizuki: "44Ti in Cas A as a test of modelsof core collapse supernovae", Int. Conf. on Astrophysics at High T and Low Tau, (RIKEN & Ohio
State University), Sedona, USA , Aug. (1999).
K. Katori: "Roles of nucleon spin in nuclear structure" ,Polusion99, (RCNP of Osaka University), Osaka,
Aug. (1999).
R. Kanungo , 1. Tanihata, Y. Ogawa, A. Ozawa, and
H. Toki: "Halo structure in 19C", 1999 Fall Meet. ofPhysical Society of Japan , Matsue, Sept. (1999).
A. Yoshimi, K. Asahi , K. Sakai, H. Ogawa, T. Suzuki,
M. Nagakura, T. Suga, A. Goto, and K. Yogo: "Thecharacteristics of 129Xe nuclear spin maser", 1999
Fall Meet. of Physical Society of Japan, Matsue,
Sept. (1999).
K. Sakai, Y. Uchiyama, T. Suzuki, M. Nagakura,
A. Goto, K. Asahi, H. Ogawa, A. Yoshimi, Y.
Mizumura, K. Yo go , T. Suga, M. Utsuro, K.
Okumura, and M. Hino: "Spin-flip magnetic deceleration of neutrons for the UCN production (I)", 1999
Fall Meet. of Physical Society of Japan, Matsue,
Sept. (1999).
Y. Mochizuki: "Exotic nuclear rod model for the originof neutron star glitches", 1999 Fall Meet. of PhysicalSociety of Japan, Matsue, Sept. (1999).
A. Ozawa: "Measurements of interaction cross sec- 'tions for unstable nuclei", Fuantei-kaku, HyperKaku Goudou Benkyoukai, (Ministry of Education ,Science, Sports and Culture) , Wako , Sept. (1999).
K. Asahi: "Nuclear moments measurements with polarized radioactive nuclear beams at RIKEN" , Int.
Workshop on Symmetry and Spin, (Faculty of Math-ematics and Physics, Charles University), Prague,
Czech Republic, Sept. (1999).
Y. Mochizuki: "Exotic nuclear rod model for the originof neutron star glitches" , Seminar at Tokyo Instituteof Technology, Tokyo, Sept. (1999).
T. Suda: "Photo disintegration reactions of 3He and
4He at TAGX" , 2nd KEK- Tanashi Int. Symp. on
Hadron and Nuclear Physics with Electromagnetic
Probes, Tanashi, Oct. (1999).
Y. Watanabe, N. Shimizu, S. Haruyama, M. Honma,
T. Mizusaki, A. Taketani, Y. Utsuno, and T. Otsuka:"A workstation farm optimized for Monte Carlo
Shell Model calculations: Alphleet", 5th Int. Conf.
on Computational Physics (ICCP5), (Kanazawa
University), Kanazawa, Oct. (1999).
T. Otsuka, N. Shimizu, S. Haruyama, M. Honma,
T. Mizusaki, A. Taketani, Y. Utsuno, and Y.
Watanabe: "Monte Carlo Shell Model calculations
for atomic nuclei and their parallel computing",
5th Int. Conf. on Computational Physics (ICCP5) ,(Kanazawa University) , Kanazawa, Oct. (1999).
Y. Mochizuki: "Exotic nuclear rod model for the originof neutron star glitches", Physical Society Meet. of
Korea, Pusan, Korea, Oct. (1999).
R. Kanungo , 1. Tanihata, and C. Samanta: "Inverse proton reactions of unstable nuclei withhalo", RCNP-TMU Symp. on Spins in Nuclear andHadronic Reactions, Ibaraki , Oct. (1999).
T. Suda: "eA (RI) collider for charge form factor measurements", Int. Workshop on Physics on eA Collider at MUSES , Wako, Nov. (1999).
S. Takeuchi, S. Shimoura, T . Motobayashi , H.
Akiyoshi, Y. Ando, N. Aoi , Zs. Fiilop, T. Gomi ,K. Higurashi , M. Hirai, N. Iwasa, H. Iwasaki, Y.
Iwata, H. Kobayashi , M. Kurokawa, T. Minemura,S. Ozawa, H. Sakurai, M. Serata, T. Teranishi , K.
Yamada, Y. Yanagisawa, Z. Liu, and M. Ishihara:"Charge exchange reaction of 14Be" , YITP Workshop on Structure and Reaction of Unstable Nuclei,
Kyoto, Nov. (1999).
N. Dinh Dang and A. Arima: "Introduction to theproceedings on quasiparticle and phonon excitations
in nuclei", RIKEN Int. Symp. on Quasiparticle andPhonon Excitations in Nuclei , Wako, Dec. (1999).
K. Morimoto: "Application for experiments using
heavy ion beam", RIKEN Symp. on Applicationof Superconductor Radiation Detectors, ST J Workshop , Wako, Dec. (1999).
Y. Mochizuki: "Exotic nuclear rod model for the origin of neutron star glitches", Seminar at Tokyo
Metropolitan University, Hachioji, Dec. (1999).
Y. Mochizuki: "44Ti in Cas A, SN 1987 A, and in laboratories", Seminar at University of Tokyo, Tokyo,
Dec. (1999).
Y. Mochizuki: "Effective halflife of ionized 44Ti and supernova remnants Cas A, RX J0852.0-4622" , Symp.
of Japanese Theoretical Astronomers , Tokyo, Dec.

(1999).
T. Kishida: "The future project at the RIKEN Accelerator Research Facility" , Workshop on Frontierof Gamma-ray Spectroscopy and Short-lived Nuclei,(JAERI), Tokaimura, Dec. (1999).
T. Nakatsukasa: "Extention of the RPA with Green's
function method to deformed states" , Workshop
on Frontier of Gamma-ray Spectroscopy and Shortlived Nuclei , (JAERI), Tokaimura, Dec. (1999).
K. Sekiguchi, H. Sakai, and H. Okamura: "Measurement of cross section and analyzing powers fordp scattering at intermediate energies and threenucleon force effects", 14th Int. Spin Physics Symp.
(SPIN 2000) , (Research Center for Nuclear Physics,
Osaka University) , Osaka, Jan. (2000) .
Y. Mochizuki: "44Ti in supernova remnants Cas A,
RX J0852-4642" , Int. Symp. on the Origin of Matterand Evolution of Galaxies 2000 (OMEG2000), (CNS
University of Tokyo, RIKEN , NAO, and KEK) ,Tanashi, Jan. (2000).
K. Ishida: "Muon catalyzed fusion experiment at
RIKEN-RAL (II)", Present Status of Nuclear Fusion Research and Muon Catalyzed Fusion, Wako,
Jan. (2000) .
T. Matsuzaki: "Muon catalyzed fusion research at
RIKEN-RAL", Present Status of Nuclear Fusion
Research and Muon Catalyzed Fusion, Wako, Jan.
(2000).
R. Kanungo , 1. Tanihata, Y. Ogawa, A. Ozawa, and H.
Toki: "Halo structure in 19C" , 10th RIKEN Winter School on Nuclear Physics with Electromagnetic
Probes at RIKEN RI-Beam Factory, Akita, Jan.
(2000).
T. Nakatsukasa and K. Yabana: "Random-phase approximation with Green's function method in deformed states", 10th RIKEN Winter School on
Nuclear Physics with Electromagnetic Probes at
RIKEN RI-Beam Factory, Akita, Jan. (2000).
K. Asahi: "Electromagnetic moments of unstable
nuclei", 10th RIKEN Winter School on Nuclear
Physics with Electromagnetic Probes at RIKEN RIBeam Factory, Akita, Jan. (2000).
Y. Mochizuki: "Half-lives of unstable nuclei produced in supernovae", Workshop on Hadron Physics
at Extreme Conditions, (JAERI), Tokaimura, Jan.
(2000).
K. Sakai and K. Asahi: "Experimental test of neutron
deceleration for Sisyphus UCN production" , Workshop on Nuclear Physics and Fundamental Physics
with Neutrons V, (KEK), Tsukuba, Jan. (2000) .
T. Ichihara, Y. Watanabe, N. Hayashi , S. Sawada, S.
Yokkaichi, A. Taketani, Y. Goto, H. En'yo, and H.
Hamagaki: "PHENIX Computing Center in Japan(CC-J) ", Int. Conf. on Computing in High Energy
and Nucler Physics (CHEP 2000), (INFN), Padova,
Italy, Feb. (2000).
Y. Mochizuki: "How nuclear and atomic physics affects385

on the maximum luminocity and the decay time oftype Ia supernovae", RIKEN Workshop on Structure
and Reaction of Nuclei: Assignments and Prospects
towards 21th Century, Wako, Feb. (2000).
H. Kato, Y. Satou, and H. Sakai: "Measurement of
deuteron polarization transfer coefficients at highly
excited continuum of 12C", 2000 Fall Meet. of the
Physical Society of Japan, Niigata, Mar. (2000).
Y. Mochizuki: "44Ti in Cas A as a test of models ofcore collapse supernovae", 2000 Spring Ann. Meet.
of Astronomy Society of Japan, Tokyo, Mar. (2000).
K. Sekiguchi, H. Sakai, and H. Okamura: "Measurement of cross section and analyzing powers for dp
scattering at intermediate energies", 2000 Spring
Meet. of the Physical Society of Japan, Suita, Mar.
(2000).
H. Kato, H. Sakai, and A. Tamii: "Measurement of polarization transfer coefficients in ap elastic scattering
at 270 MeV", 2000 Spring Meet. of the Physical Society of Japan, Suita, Mar. (2000).
M. Hatano, T. Wakui, and H. Sakai: "Developmentof a polarized proton solid target by means of integrated solid effect at high temperature and low
magnetic field", 2000 Spring Meet. of the PhysicalSociety of Japan, Suit a, Mar. (2000).
N. Kawamura, K. Nagamine, T. Matsuzaki, K. Ishida,
S. N. Nakamura, Y. Matsuda, S. Sakamoto, M.
Tanase, M. Kato, K. Kurosawa, H. Sugai, K. Kudoh,
N. Takeda, and G. H. Eaton: "Muon catalyzed fusion experiment for D-T mixture at RIKEN-RAL
muon facility: p,CF in cryo-solid" , 2000 Spring Meet.
of the Physical Society of Japan, Suita, Mar. (2000).
H. Ogawa, K. Asahi, M. Nagakura, T. Suzuki, A.
Goto, T. Suga, K. Yogo, H. Miyoshi, T. Honda, K.
Sakai, A. Yoshimi, H. Ueno, Y. Watanabe, N. Imai,
K. Yoneda, N. Aoi, N. Fukuda, Y. Kobayashi, A.
Yoshida, T. Kubo, H. Sakurai, W.-D. Schmidt-Ott,
G. Neyens , and S. Teughels: "The measurement of
15C magnetic moment", 2000 Spring Meet. of the
Physical Society of Japan, Suit a, Mar. (2000).
T. Suzuki, H. Ogawa, K. Asahi, H. Miyoshi, M.
Nagakura, A. Goto, T. Suga, K. Yogo, T. Honda,
K. Sakai, A. Yoshimi , H. Ueno, N. Imai , K. Yoneda,
N. Fukuda, Y. Watanabe, N. Aoi, Y. Kobayashi, A.
Yoshida, T. Kubo, H. Sakurai, W.-D. Schmidt-Ott,
G. Neyens, and S. Teughels: "Electric quadrupole
moment of neutron halo nucleus 17B", 2000 Spring
Meet. of the Physical Society of Japan, Suit a, Mar.
(2000) .
K. Yo go , H. Ogawa, K. Sakai, A. Yoshimi , T. Suzuki,
M. Nagakura, A. Goto, T. Suga, and K. Asahi:"Cross polarization effect on LMR of 18N implantedin Mg", 2000 Spring Meet. of the Physical Societyof Japan, Suita, Mar. (2000) .
Y. Mochizuki: "Nuclear , -ray astronomy", 2000
Spring Meet. of the Physical Society of Japan,
Higashiosaka, Mar. (2000).

386

K. Asahi: "Electromagnetic moments of light neutronrich nuclei measured with polarized radioactive ion
beams", Int. RIKEN Symp. on Shell Model 2000,
Wako, Mar. (2000).
H. Ogawa, K. Sakai, T. Suzuki, M. Nagakura, H.
Miyoshi, K. Asahi, K. Yo go , A. Goto, T. Suga, T.
Honda, A. Yoshimi, H. Veno, N. Imai, Y. Watanabe,
K. Yoneda, N. Fukuda, N. Aoi, Y. Kobayashi, W.-D.
Schmidt-Ott, G. Neyens, S. Teughels, A. Yoshida,
T. Kubo, and M. Ishihara: "The measurement of
15-C magnetic moment and 17B electric quadrupole
moment", Int. RIKEN Symp. on Shell Model 2000,
Wako, Mar. (2000).
K. Sekiguchi, H. Sakai, and H. Okamura: "Measurement of cross sections and analyzing powers for thed-p elastic scattering at intermediate energies", 16th
IUPAP Int. Conf. on Few-Body Problems in Physics,
Taipei, Taiwan, Mar. (2000).
H. Sakai: "Polarization transfer measurements fordp scattering at 270 MeV" , 16th IUPAP Int. Conf.
on Few-Body Problems in Physics, Taipei, Taiwan,
Mar. (2000).
T. Uesaka, H. Sakai, H. Okamura, A. Tamii, Y. Satou,
T. Ohnishi, K. Sekiguchi, K. Yako, K. Suda, S.
Sakoda, J. Nishikawa, M. Hatano, H. Kato, Y.
Maeda, N. Sakamoto, T. Wakasa, and K. Itoh:"3 He(J:p)4He reaction at intermediate energies",
16th IUPAP Int. Conf. on Few-Body Problems in
Physics, Taipei, Taiwan, Mar. (2000).
T. Kishida: "Secondary fusion reaction of high spinisomeric beams" , Work on Science with Low-energy
Radioactive Nuclear Beams 2000 , (High Energy Acclerarater Research Organization) , Tanashi, Mar.
(2000).
T. Kishida: "Gas target system for production of
secondary beams and study of nuclear structure",Work on Science with Low-energy Radioactive Nuclear Beams 2000, (High Energy Acclerarater Research Organization) , Tanashi, Mar. (2000).
H. Ogawa, K. Asahi, M. N agakura, T. Suzuki, A.
Goto, T. Suga, K. Yogo, H. Miyoshi, T. Honda, K.
Sakai, A. Yoshimi, H. Veno, Y. Watanabe, N. Imai,
K. Yoneda, N. Aoi, N. Fukuda, Y. Kobayashi, A.
Yoshida, T. Kubo, H. Sakurai, W.-D. Schmidt-Ott,
G. Neyens, and S. Teughels: "Electromagnetic moment of 17B and 15C", Work on Science with Lowenergy Radioactive Nuclear Beams 2000, (High Energy Acclerarater Research Organization), Tanashi,
Mar. (2000).
T. Suda: "e-A collider at RIKEN/MUSES", Workshop on eA Collider, (Gesellschaft Schwerionenforschung), Darmstadt, Germany, Mar. (2000).
K. Ishida: "X-ray studies on muon sticking and regeneration in D-T p,CF", Workshop on Muon Catalyzed Fusion Studies: Interaction between Theoretical and Experimental Studies, (KEK-MSL and
RIKEN-MUON), Tsukuba, Mar . (2000).

T. Matsuzaki: "Recent experimental results on t-t
muon catalyzed fusion", Workshop on Muon Catalyzed Fusion Studies: Interaction between Theoretical and Experimental Studies, (KEK-MSL and
RIKEN-MUON), Tsukuba, Mar. (2000).
K. Yoneda, H. Sakurai, T. Gomi , T. Motobayashi,
N. Aoi, N. Fukuda, U. Futakami, Z. Gacsi, K.
Higurashi, N. Imai, N. Iwasa, H. Iwasaki, T . Kubo,
M. Kunibu, M. Kurokawa, Z. Liu, T. Minemura,
A. Saito, M. Serata, S. Shimoura, S. Takeuchi, Y.
Watanabe, K. Yamada, Y. Yanagisawa, K. Yogo,
A. Yoshida, and M. Ishihara: "Gamma-ray spectroscopy of 34Mg via RI beam fragmentation", 5thInt. Conf. on Radioactive Nuclear Beams (RNB5) ,(CERN and the ISOLDE collaboration), Divonne,
France, Apr. (2000).
M. Matsuo, T. Nakatsukasa, and K. Matsuyanagi:"Adiabatic collective path for large amplitude shape
dynamics", YITP Workshop on Dynamical Process
in Nuclear Structure and Low-Intermediate Energy
Heavy-Ion Nuclear Reactions, (Kyoto University),
Kyoto, Apr. (2000).
A. Ozawa: "Nuclear radii and halo", Int. Symp. on
Exotic Nuclear Structures, (ATOMKI), Debrecen,
Hungary, May (2000).
S. N. Nakamura: "Measurement of the Fermi coupling constant", NuFact '00 Workshop (Muon Storage Ring for a Neutrino Factory), (Lawrence Berkeley National Laboratory) , Monterey, USA , May(2000).
T. Matsuzaki: "Tritium gas handling system at
RIKEN-RAL muon facility", RIKEN Symp. on Scientific Research Using Tritium and Related Engineering, Wako, May (2000).
N. Dinh Dang: "Single and multiphonon resonances
at zero and finite temperatures within the phonon
damping model" , Structure of Nucleus at the Dawnof the Century (Bologna 2000), (University of
Bologna) , Bologna, Italy, 11:ay (2000).
T. Matsuzaki: "Muon catalyzed fusion research at
RIKEN-RAL muon facility", Denki Kagakukai the
4th Seminar, Tokyo, June (2000).
T. Ohnishi, H. Sakai, H. Okamura, T. Niizeki, K.
Sekiguchi, N. Sakamoto, T. Uesaka, H. Ohnuma, Y.
Satou, and K. Yakou: "Study of spin-isospin excitations in 11 Be via the (d, 2He) reaction at 270 MeV" ,Int. Conf. on Giant Resonances (GR2000), (RCNP
of Osaka University), Osaka, June (2000).
K. Katori: "Isospin symmetry-structure study at new
high-resolution course of RCNP", Int. Conf. on Giant Resonances (GR2000), (RCNP of Osaka University), Osaka, June (2000).
N. Dinh Dang: "Description of the hot GDR, multiphonon GDR in stable nuclei, and GDR in unstable nuclei within the phonon damping model", Int.
Conf. on Giant Resonances (GR2000), (RCNP of
Osaka University), Osaka, June (2000).

V. Kim Au, N. Dinh Dang, and A. Arima: "Electromagntic cross sections of double giant dipole
resonances in 136Xe and 208Pb within the phonon
damping model", Int. Conf. on Giant Resonances(GR2000), (RCNP of Osaka University), Osaka,June (2000).
K. Eisenman, J. Seitz, N. Dinh Dang, and M.
Thoennessen: "Evolution of the giant dipole resonance width with nuclear temperature in 120Sn" ,Int. Conf. on Giant Resonances (GR2000), (RCNP
of Osaka University), Osaka, June (2000).
A. A. Korsheninnikov, M. Golovkov, A. Ozawa, K.
Yoshida, I. Tanihata, Z. Fulop, K. Kusaka, K.
Morimoto, H. Otsu, H. Petrascu, F. Tokanai,
D. Bogdanov, M. Chelnokov, A. Fomichev, V.
Gorshkov, Y. Oganessian, A. Rodin, S. Sidorchuk, S.
Stepantsov, G. Ter-Akopian, R. Wolskii, W. Mittig,
P. Roussel-Chomaz, H. Savajols, E. Kuzmin, E.
Nikolskii, and A. Ogloblin: "Superheavy hydrogen
5H. Spectroscopy of 7He", Int. Conf. on Nuclear
Physics, Clustering Phenomena in Nuclear Physics,
St. Petersburg, Russia, June (2000).
Y. Mochizuki: "Ionization effects of 44Ti in Cas A, RX
J0852-4622, and SN 1987A", Int. Symp. on Nuclei
in the Cosmos 2000, (Univesity of Aarhas), Aarhus,
Denmark, June (2000).
N. Nakao, T. Kurosawa, T . Nakamura, and Y.
Uwamino: "Development of quasi-monoenergetic
neutron field and measurements of response functionof organic scintillator for neutron energy range from66 to 206 MeV", Int. Workshop on Neutron Field
Spectrometry in Science, Technology and Radiation
Protection, (Physikalisch-Technische Budesanstalt),Pisa, Italy, June (2000).
A. A. Korsheninnikov, M. Golovkov, I. Tanihata,
D. Bogdanov, M. Chelnokov, A. Fomichev, V.
Gorshkov, Y. Oganessian, A. Rodin, S. Sidorchuk, S.
Stepantsov, G. Ter-Akopian, R. Wolskii, W. Mittig,
P. Roussel-Chomaz, H. Savajols, E. Kuzmin, E.
Nikolskii, and A. Ogloblin: "Superheavy hydrogen 5H" , Nucleus-Nucleus Collisions 2000, (GANIL ,GSI), Strasbourg, France, July (2000).
N. Nakao, T. Shibata, T. Nunomiya, T. Nakamura,
E. Kim , T. Kurosawa, S. Taniguchi, M. Sasaki, H.
Iwase , Y. Uwamino, S. Ito, P. Wright, and D. R.
Perry: "Deep penetration experiment at ISIS", 5thSpecialists' Meet. on Shielding Aspects of Accelerators, Targets and Irradiation Facilities (SATIF5) , (OECD/Nuclear Energy Agency), Paris, France,
July (2000).
Y. Mochizuki, I. Tanihata, and Y. Yano: "Video: The
quest for the origin of the elements", CNS /RIKEN
Symp. on Physics of RI-Beam at Low Energy, Wako,
Aug. (2000).
Y. Mochizuki: "Recent topics in neutron star physics
and in nuclear gamma ray astronomy", Lecture Series (invited) at 14th Symp. of Hokkaido Theoretical387

Nuclear Physics Group, Sapporo, Aug. (2000).
T. Nakatsukasa and K. Yabana: "Linear response theory in the continuum", RIKEN Workshop on Computational Physics Approaches in Nuclear Mean
Field Theory, Wako, Aug. (2000).
T. Nakatsukasa and K. Yabana: "The RPA with
Green's function method on 3D real space", 55th
Ann. Meet. of Physical Society of Japan, Niigata,
Sept. (2000).
A. Ozawa: "A new magic number, N = 16, near to
the neutron drip-line", 55th Ann. Meet. of PhysicalSociety of Japan, Niigata, Sept. (2000) .
Y. Aoki, K. Yoshida, T. Nakagawa, K. Nakagawa, and
J. Kasagi: "Hot Giant Dipole Resonace of 209Bi'',
55th Annual Meeting of the Physical Society ofJapan, Niigata, Sept. (2000).
Y. Mochizuki, 1. Tanihata, and A. Ozawa: "On themagic numbers related to r-process nucleosynthesis", 55th Annual Meeting of the Physical Societyof Japan, Niigata, Sept. (2000).
H. Sakai: "dp and rid scatterings at intermediate energy and three-nucleon force effects", 17th European
Conf. on Few-Body Problems in Physics, (University
of Evora), Evora, Portugal, Sept. (2000).
K. Yoshida: "DGR observed through heavy ion reactions", Symp. on "2 Phonon Giant Resonance"and "Change of Nuclear Lifetime", (Laboratory of
Nuclear Science, Tohoku University), Sendai, Sept .
(2000).
H. Kato, Y. Satou, and H. Sakai: "Deuteron polarimeter DPOL and calibration of the system", 14th Int.
Spin Physics Symp. (SPIN 2000), (RCNP, Osaka
University), Osaka, Oct. (2000) .
T. Ohnishi, H. Sakai, H. Okamura, T. Niizeki, K .
Sekiguchi, N. Sakamoto, T. Uesaka, H. Ohnuma, Y.
Satou, and K. Yakou: "Systematic study of spinisospin excitations in neutron rich light nuclei via
the (d,2He) reaction at 270 MeV", 14th Int. Spin
Physics Symp. (SPIN2000), (RCNP of Osaka University), Osaka, Oct. (2000).
T. Wakui, M. Hatano, H. Sakai, A. Tamii, and T.
Uesaka: "Development of a polarized proton target in a low magnetic field at high temperature",
14th Int. Spin Physics Symp. (SPIN2000), (RCNP
of Osaka University), Osaka, Oct. (2000).
T. Uesaka, J. Nishikawa, H. Okamura, H. Sakai,
M. Hatano, K. Itoh, H. Kato, Y. Maeda, T.
Ohnishi, T. Saito, N. Sakamoto, S. Sakoda, Y.
Satou, K. Sekiguchi, K. Suda, A. Tamii, N.
Uchigashima, K. Yako, S. Yamamoto, T. Wakasa,
and T . Wakui: "Role of deuteron internal variablesin the 3He(d,p)4He reaction", 14th Int. Spin Physics
Symp. (SPIN2000) , (RCNP of Osaka University),
Osaka, Oct. (2000).
Y. Mochizuki: "Evolution of the elements in the universe", Lecture Series (invited) at Department of
Physics, Shizuoka University, Shizuoka, Oct. (2000).

388

T. Nakatsukasa and K. Yabana: "Linear response theory in the continuum", Nuclear Physics Seminar at
Tohoku University, Sendai, Oct. (2000).
Y . Mochizuki: "Retardation of 44Ti decay in supernova remnants and its importance", Seminar at Department of Physics, Chiba University, Chiba, Oct.
(2000).
Y. Mochizuki: "Exotic nuclear rod model for the originof neutron star glitches" , Seminar at Department of
Physics, Sophia University, Tokyo, Oct. (2000).
A. Ozawa: "New magic number, N = 16, near theneutron drip line", 2000 Symp. on Nuclear Data,(JAERI), Tokaimura, Nov. (2000) .
A. Ozawa: "Measurement of interaction cross-sections
and related topics", Int. Symp. on Perspectives
in Physics with Radioactive Isotope Beams 2000 ,Hayama, Nov. (2000).
Y. Mochizuki: "Retardation of 44Ti decay in supernova remnants and its importance", Nuclear Physics
Seminar at Hosei University, Tokyo, Nov. (2000).
S. Fujii and S. Fujii: "Shell-model calculations forlambda hypernuclei using microscopic effective interactions", RIKEN-RCNP Workshop on Exotics in
Hadron Many Body Systems, Nara, Nov. (2000).
Y . Mochizuki: "Exotic nuclear rod model for the origin of neutron star glitches", Theoretical Nuclear
Physics Seminar at the University of Tokyo, Tokyo,
Nov. (2000).
A. Ozawa: "Recent RI beam program at RIKEN
and related topics" , Int. Symp. on Nuclear Physics(ISNP2K), (Bhabha Atomic Research Center),
Mumbai, India, Dec. (2000).
Y. Mochizuki: "How can glitches in neutron stars occur?", Lecture at Department of Physics, Ryukyu
University, Okinawa, Dec. (2000).
Y. Mochizuki: "Nuclear Astrophysics: Evolution of
the elements in the universe", Lecture Series (invited) at Department of Physics, Ryukyu University,
Okinawa, Dec. (2000).
Y. Mochizuki: "On the magic numbers related to rprocess nucleosynthesis", 13th Symp. of Associationof Japanese Theoretical Astronomers, Kyoto, Dec.
(2000).
Y. Mochizuki: "Retardation of 44Ti decay in supernova
remnants and its importance", Theoretical Nuclear
Physics Seminar at the University of Tokyo, Tokyo,
Dec. (2000).

3.

Atomic and solid-state physics

1. Watanabe,

M. Akoshima, Y. Koike, and K.
Nagamine: "Possibility of '~ problem' in Zn-doped
Bi-2212 system", Int. Workshop on JHF Science(JHF9S), (Meson Science Laboratory, High Energy
Accelerator Research Organization and Meson Science Association) , Tsukuba, Mar. (199S).
N. Wada, A. Yamaguchi, H. Yano, K. Awaga, 1.

Watanabe, S. Ohira, and K. Nagamine: "Twodimensional S = 1 spin-gap antiferromagnet mMPYNN·BF 4", Int. Workshop on JHF Science(JHF98), (Meson Science Laboratory, High Energy
Accelerator Research Organization and Meson Science Association), Tsukuba, Mar. (1998).
S. Ohira, 1. Watanabe, R. Imachi, N. Ishida, T.
Nogami, and K. Nagamine: ",uSR studies on organic radical ferromagnets, 4-anylmethyleneaminoTEMPO", Int. Workshop on JHF Science (JHF98),(Meson Science Laboratory, High Energy Accelerator Research Organization and Meson Science Association), Tsukuba, Mar. (1998).
J. Arai, T. Ishiguro, 1. Watanabe, and K. Nagamine:",uSR study in Lal-xSrxCuo.ggFeo.01 0 4" , Int. Workshop on JHF Science (JHF98), (Meson Science Laboratory, High Energy Accelerator Research Organization and Meson Science Association), Tsukuba,Mar. (1998).
K. Shimomura, 1. Watanabe, and K. Nagamine:"Muon dynamics in GaAs under laser irradiation",
Int. Workshop on JHF Science (JHF98), (Meson
Science Laboratory, High Energy Accelerator Research Organization and Meson Science Association), Tsukuba, Mar. (1998).
V. V. Krishunamurthy, 1. Watanabe, H. Kuwahara,
Y. Tokura, and K. Nagamine: "Magnetism andnon- Fermi liquid scaling in Kondo lattice systems" ,Int. Workshop on JHF Science (JHF98), (Meson
Science Laboratory, High Energy Accelerator Research Organization and Meson Science Association), Tsukuba, Mar. (1998).
T. Takabatake, D. T. Adroja, 1. Watanabe, and K.
Nagamine: ",uSR studies of a Heavy-Fermion compound Ce7Ni3 with inequivalent Ce sites", Int.
Workshop on JHF Science (JHF98), (Meson Science Laboratory, High Energy Accelerator Research Organization and Meson Science Association), Tsukuba, Mar. (1998).
1. Watanabe, M. Akoshima, Y. Koike, and K.
N agamine: "Magnetic instability observed by ,uSR
in Zn-doped Bi-2212 system at the hole density of~", NEDO Workshop on Strongly Correlated Electron Systems, Los Angels, USA, Mar. (1998).
1. Watanabe, M. Akoshima, Y. Koike, and K.
N agamine: ",uSR on magnetic state of Zn-doped
Bi-2212 system", Int. Conf. on Strongly CorrelatedElectrqn Systems (SCES98), Paris, France, July
(1998).
1. Watanabe and K. N agamine: ",uSR study of magnetically ordered state of Zn-doped La-Sr system at holedensity of around ~", Int. Conf. on Strongly Correlated Electron Systems (SCES98), Paris, France,
July (1998).
V. V. Krishunamurthy, 1. Watanabe, S. Ohira, K.
Nishiyama, K. Nagamine, M. Ishikawa, and D.
H. Eom: ",u+SR observation of magnetic orderingand non-Fermi liquid scaling in CeCo(Gel.sSi1.2)",
Int. Conf. on Strongly Correlated Electron Systems(SCES98), Paris, France, July (1998).
Y. Yamamoto, Y. Miyako, T. Takeuchi, 1. Watanabe,
K. Nishiyama, K. Shimomura, and K. Nagamine:"Low temperature properties of the Heavy-Fermion
Ce(Rul-xRhxhSi2 at the magnetic-nonmagnetic
boundaries", Int. Conf. on Strongly Correlated Electron Systems (SCES98), Paris, France, July (1998).
V. V. Krishunamurthy, 1. Watanabe, K. Nagamine, H.
Kuwahara, and Y. Tokura: ",u+SR observation ofcritical spin dynamics at the ferromagnetic orderingin Ndo.sSro.sMn04", 11th Int. Conf. on Hyperfine
Interactions, Durban, South Africa, Aug. (1998).
V. V. Krishunamurthy, 1. Watanabe, K. Nagamine, C.
Geibel, G. Sparn, and F. Sterlich: ",u+SR study on
Heavy-Fermion magnetism in Ce(Cul-xNixhGe2",
11th Int. Conf. on Hyperfine Interactions, Durban,
South Africa, Aug. (1998).
1. Watanabe, M. Akoshima, Y. Koike, and K.
Nagamine: "Possibility of '~ problem' in Zn-doped
Bi2212 system", 3rd Workshop on Neutron Science
Project: Science and Technology in the 21st Century Opened by Intense Spallation Neutron Source,(JAERI), Tokaimura, Mar. (1999).
Y. Koike, M. Akoshima, T. Adachi, N. Kakinuma, H.
Noji, T. Nishizaki, N. Kobayashi, 1. Watanabe, and
K. Nagamine: "~problem in the La-, Bi and Ybased cuprates and new anomalies in the overdoped
region of the La-based cuprate", 2nd Int. Conf. on
New Theories, Discoveries, and Applications of Superconductors and Related Materials, Las Vegas,
USA, May (1999).
1.
Watanabe,M.
Akoshima,
Y.
Koike,
andK.
Nagamine:",u+SR study on
Bi2Sr2Cal-x Y x(Cul-yZnyhOs+8
aroundthehole concentration of ~ per Cu", Int. Conf. on
Physics and Chemistry of Molecular and Oxide
Superconductors (MOS99), Stockholm, Sweden,
July (1999).
J. Arai, T. Ishiguro, 1. Watanabe, and K. Nagamine:",u+SR study in La2- xSrxCUl-yZny04 with x"'~" ,Int. Conf. on Physics and Chemistry of Molecularand Oxide Superconductors (MOS99), Stockholm,
Sweden, July (1999).
M. Akoshima, H. Noji, Y. Koike, T. Nishizaki, N.
Kobayashi, 1. Watanabe, and K. Nagamine: "Transport and ,u+SR at P"'~ in the Bi-2212 and Y123 phases", Int. Conf. on Physics and Chemistryof Molecular and Oxide Superconductors (MOS99),
Stockholm, Sweden, July (1999).
1. Watanabe, M. Akoshima, Y. Koike, S. Ohira, W.
Higemoto, and K. Nagamine: ",uSR studies on the'~effect' in Zn-substituted Bi2212 system", 22nd Int.
Conf. on Low Temperature Physics (LT22), Helsinki,
Finland, Aug. (1999).
1. Watanabe, N. Wada, K. Awaga, S. Ohira, and K.

389

N agamine: "p'sR study on dynamics of dimer spin in
the 2D organic antiferromagnet, m-MPYNN ·BF 4'"
22nd Int. Conf. on Low Temperature Physics(LT22), Helsinki , Finland, Aug. (1999).
I. Watanabe, M. Akoshima, Y. Koike, S. Ohira, W.
Higemoto, and K. Nagamine: "p,SR study on the
spin/ charge ordered state of the hole-doped high Tc
oxides around the hole concentration of ~ " , 8th Int.
Conf. on Muon Spin Rotation, Relaxation and Resonance (p,SR99), Les Diablerets, Switzerland, Aug.
(1999).
I. Watanabe, N. Wada, K. Awaga, S. Ohira, and K.
Nagamine: "p,SR study on the 2D S = 1 Kagomeorganic antiferromagnet , m-MPYNN·(BF 4,CI0 4)" ,8th Int. Conf. on Muon Spin Rotation, Relaxation
and Resonance (p,SR99), Les Diablerets, Switzerland, Aug. (1999).
W. Higemoto, H. Tanaka, I. Watanabe, S. Ohira, A.
Fukaya, and K. Nagamine: ':Anomalous magnetic
field dependence of the muon spin relaxation in
S = 1 double chain systems KCuCl 3 and TICuCI 3" ,8th Int. Conf. on Muon Spin Rotation, Relaxation
and Resonance (p,SR99) , Les Diablerets, Switzerland , Aug. (1999).
T. Ishiguro, M. Hirai , H. Shinmen, J. Arai, I.
Watanabe , and K. Nagamine: "Zn-induced magnetic order detected by p,SR around x = ~ inLa2- xSrxCUl-yZny04", 8th Int. Conf. on Muon
Spin Rotation, Relaxation and Resonance (j./,SR99),
Les Diablerets, Switzerland, Aug. (1999).
M. Mekata, K. M. Kojima, I. Watanabe, K. Nagamine,and H. Ikeda: "Magnetic ordering and excitationin Ising spin nets Rb 2Co 1 - xMgx F 4", 8th Int. Conf.
on Muon Spin Rotation, Relaxation and Resonance(p,SR99) , (Paul Scherrer Institut , EPS , Universitas
Turicensis, and ETH), Les Diablerets , Switzerland,Aug. (1999).
M. Matsuda, I. Watanabe, and K. Nagamine: "Magnetic ordering in La2Cu205", 8th Int. Conf. on
Muon Spin Rotation , Relaxation and Resonance(p,SR99) , (Paul Scherrer Institut, EPS , Universitas
Turicensis, and ETH), Les Diablerets, Switzerland,Aug. (1999).
V. V. Krishunamurthy , I. Watanabe, K . Nagamine,
H. Kuwahara, and Y. Tokura: "Spin dynamics in
Ndl- xSrxMn03 with x = 0.5 and x = 0.55" , 8thInt. Conf. on Muon Spin Rotation , Relaxation andResonance (p,SR99), (Paul Scherrer Institut , EPS ,Universitas Turicensis , and ETH), Les Diablerets,
Switzerland, Aug. (1999).
F. L. Pratt, S. J. Blundell, Th. Jestadt , B. W. Lovett ,A. Husmann , I. M. Marshall, W. Hayes, A. P.
Monkman, I. Watanabe, and K. Nagamine: "p,SRon conducting and non-conducting polymers", 8thInt. Conf. on Muon Spin Rotation, Relaxation andResonance (p,SR99), (Paul Scherrer Institut, EPS,
Universitas Turicensis, and ETH), Les Diablerets,

390

Switzerland , Aug. (1999).
W. Higemoto, I. Watanabe, K. Nagamine, S. Kuroda,and H. Takita: "Investigation of the dynamics of flux
line lattice under an electric current", 8th Int. Conf.
on Muon Spin Rotation , Relaxation and Resonance(p,SR99) , (Paul Scherrer Institut , EPS, Universitas
Turicensis, and ETH) , Les Diablerets, Switzerland ,Aug. (1999).
F. L. Pratt, S. J. Blundell, A. Husmann , I. M.
Marshall, B. W. Lovett, W. Hayes , S. L. Lee, C.
Ager, T. Sasaki, T. Toyoda, V. N. Laukhin, E.
Laukhina, I. Watanabe, and K. Nagamine: "BEDTTTF superconductors studied by p,SR", 8th Int.
Conf. on Muon Spin Rotation, Relaxation andResonance (p,SR99) , (Paul Scherrer Institut, EPS,
Universitas Turicensis, and ETH), Les Diablerets,
Switzerland , Aug. (1999).
S. Ohira, I. Watanabe, F. 1. Pratt, N. Ishida, T.
Nogami, and K. Nagamine: "Muon spin relaxation
and resonsnce studies on the organic radical magnet,
4-arylmethykeneamino-TEMPO", 8th Int. Conf. on
Muon Spin Rotation, Relaxation and Resonance(p,SR99) , (Paul Scherrer Institut, EPS, Universitas
Turicensis, and ETH) , Les Diablerets , Switzerland,Aug. (1999).
Y. Miyake, K . Shimomura, Y. Matsuda, R. J.
Sheuermann, P. Bakule, S. Makimura, P. Strasser, S.
N. Nakamura, K. Ishida, T . Matsuzaki, I. Watanabe,
and K. Nagamine: "Set-up for the ultra slow muon
experiment by laser resonant ionization method at
RIKEN-RAL" , 8th Int. Conf. on Muon Spin Rotation, Relaxation and Resonance (p,SR99) , (PaulScherrer Institut, EPS, Universitas Turicensis, andETH) , Les Diablerets, Switzerland, Aug. (1999).
A. Kratzer, G. M. Kalvius , T. Takabatake, K.
Umeo, D. T. Adroja, Y. Echizen, I. Watanabe, R.
Wappling, D. R. Noakes, C. U. Jackson, and C. E.
Stronach: "p,SR studies of Ce7Ni3" , 8th Int. Conf.
on Muon Spin Rotation, Relaxation and Resonance(p,SR99) , (Paul Scherrer Institut, EPS , Universitas
Turicensis , and ETH), Les Diablerets, Switzerland,Aug. (1999).
V. V. Krishunamurthy , I. Watanabe, K. Nagamine,
J. Kitagawa, M. Ishikawa, and T. Komatsubara:"p,+SR study of ordering phenomenon in the HeavyFermion state of Ce3Pd2oGe6 single crystal", 8thInt. Conf. on Muon Spin Rotation, Relaxation andResonance (p,SR99), (Paul Scherrer Institut, EPS ,Universitas Turicensis , and ETH), Les Diablerets,
Switzerland, Aug. (1999) .
V. V. Krishunamurthy, K. Nagamine, I. Watanabe,
K. Nishiyama, S. Ohira, M. Ishikawa, and D. H.
Eom: "Non-Fermi liquid behavior in CeCoGe3-xSix
alloys", 8th Int. Conf. on Muon Spin Rotation, Relaxation and Resonance (p,SR99), (Paul Scherrer Institut, EPS, Universitas Turicensis, and ETH), Les
Diablerets, Switzerland, Aug. (1999) .

Y. Kobayashi, Y. Yoshida, A. Yoshida, Y. Watanabe,
K. Hayakawa, K. Yukihira, F. Shimura, and F.
Ambe: "In-beam Mossbauer study of 57Mn/57Fe
in Si following projectile fragmentation and implantation" , Int. Conf. on the A pplication of
the Mossbauer Effect 1999, Garmish-Partenkirchen,
Germany, Aug. (1999).
1. Shimamura: "Dynamics of three-body and fourbody exotic-atom systems", ITAMP Workshop on
Fragmentation and Recombination in Novel 3- and
4-Body Systems, (Institute for Theoretical Atomic
and Molecular Physics), Cambridge, USA, Nov.
(1999).
M. Akoshima, Y. Koike, 1. Watanabe, and K.
Nagamine: "Suppression of the high-Tc superconductivity and the stripe correlations in the Bi-2212
and Y-123 phases around pt'-.Jl/8", Dai 54-kai Ohyobutsuri Gakkai Tohoku-shibu Gakujutsu Koen-kai,
Sendai, Dec. (1999).
Y. Morishita: "Study of initially populated states ofslow highly charged ions interacting with Ni micro
capillary" , RIKEN Symp. on Studies on Condensed
Matter Physics, Atomic Physics, Hyperfine Interactions and Biomedical Sciences Using RIKEN Accelerators, Wako, Jan. (2000).
T. Azuma and Y. Yamazaki: "Coherent resonant excitation and high resolution spectroscopy", RIKEN
Symp. on Studies on Condensed Matter Physics,
Atomic Physics, Hyperfine Interactions and Biomedical Sciences Using RIKEN Accelerators, Wako, Jan.
(2000).
Y. Koike, M. Akoshima, 1. Watanabe, and K.
Nagamine: "Transport and /LSR studies on the ~anomaly in the Bi-2212 and Y-123", US-Japan Neutron Scattering Workshop on Stripe in Transition
Metals Oxides, Honolulu, USA, Jan. (2000).
Y. Koike, M. Akoshima, 1. Watanabe, and K.
Nagamine: "~anomaly in the Bi-2212 and Y-123
phases" ,6th Int. Conf. on Materials and Magnetismof Superconductivity and High Temperature Superconductors, Houston, USA, Feb. (2000).
1. Shimamura, M. Kimura, and G. Va. Korenman:"Metastable antiprotonic Lithium", Workshop on
the Theory of Antimatter Science Using Antiprotons, Atami, Feb. (2000).
Y. Yamazaki: "Production of ultra slow antiproton beams and elementary collision processes withatoms", Workshop on the Theory of Antimatter Science Using Antiprotons, Atami, Feb. (2000).
T. Ishiguro, T. Oda, H. Shinmen, M. Hirai, J.
Yokoyama, J. Arai, 1. Watanabe, and K. Nagamine:"Zn-substitution effect in La2-xSrxCU1-yZny04
around the optimul doped region studied by /L+SR" ,2000 Spring Meet. of the Physical Society of Japan,
Suita, Mar. (2000).
M. Mekata, K. M. Kojima, S. Ito, 1. Watanabe, and K.
Nagamine: "Process of the ordering of the diluted

ising-spin net", 2000 Spring Meet. of the PhysicalSociety of Japan, Suita, Mar. (2000).
M. Akoshima, 1. Watanabe, K. Nishimaki, M. Aoyama,
Y. Koike, S. Ohira, W. Higemoto, and K. Nagamine:" ~ anomaly in YBa2Cu3-2xZn2y07-<5 observed by/LSR" , 2000 Spring Meet. of the Physical Society ofJapan, Suita, Mar. (2000).
Y. Yoshida, Y. Kobayashi, F. Ambe, A. Yoshida, Y.
Yano, and F. Shimura: "Studies on jump process of
Fe atoms located at interstitial and substitutional
position in Si", 2000 Spring Meet. of the PhysicalSociety of Japan, Suita, Mar. (2000).
M. Wada, S. Okada, Y. Okada, 1. Katayama, H.
Kawakami, K. Noda, T. Nakamura, S. Ohtani, Y.
Nakai, T. M. Kojima, Y. Kanai, T. Kambara, andY. Yamazaki: "RF ion guide for collecting ions inenergetic radioactive beams", 2000 Spring Meet. of
the Physical Society of Japan, Suita, Mar. (2000).
T. Kambara, Y. Kanai, T. M. Kojima, Y. Nakai,
Y. Yamazaki, and K. Kageyama: "Acoustic emission from solid irradiated by fast heavy ions", 2000
Spring Meet. of the Physical Society of Japan, Suita,
Mar. (2000).
Y. Iwai, S. Thuriez, R. Hutton, Y. Kanai , H. Oyama,
K. Ando, H. Masuda, T. Azuma, K. Komaki, and Y.
Yamazaki: "High resolution soft X-ray spectroscopyof slow highly charged ions through Ni microcapillary" , 2000 Spring Meet. of the Physical Society ofJapan, Suita, Mar. (2000).
D. Murakoshi, N. Okabayashi, Y. Iwai , H. Torii, K.
Kuroki , H. Masuda, K. Komaki, and Y. Yamazaki:"Measurement of charge state distribution of Xe q +transmitted through Ni micro-capillaries", 2000
Spring Meet. of the Physical Society of Japan, Suita,
Mar. (2000).
A. Endo , N. Okabayashi, H. Torii, K. Kuroki, K.
Komaki , and Y. Yamazaki: "The design of a miniEBIS using high-T c superconductors", 2000 Spring
Meet. of the Physical Society of Japan, Suita, Mar.
(2000).
M. Hoshino , M. Kitajima, Y. Nakai, Y. Kanai, andY. Yamazaki: "The collision energy-dependence of
double electron capture cross sections in low energy
C4 + -He collision" , 2000 Spring Meet. of the PhysicalSociety of Japan, Suita, Mar. (2000) .
Y. Morishita, Y. Yamazaki, K. Kuroki , H. Torii, K.
Komaki, H. Masuda, R. Hutton, K. Ando, K. Ishii,
and M. Sekiguchi: "Visible light emission from slow
highly charged ions transmitted through Ni microcapillary (3)", 2000 Spring Meet. of the Physical Society of Japan, Suita, Mar. (2000).
T. Ichioka, H. Higaki, M. Hori, K. Yoshiki Franzen,
N. Kuroda, B. Ujbari, N. Oshima, K. Kuroki, A.
Mohri, K. Komaki, and Y. Yamazaki: "Developmentof a trap for experiments using ultracold antiprotons(II)", 2000 Spring Meet. of the Physical Society ofJapan , Suita, Mar. (2000).

391

Y. Yamazaki: "Research of ion-matter interaction at
RIKEN RI-Beam Factory", 2000 Spring Meet. of the
Physical Society of Japan, Suita, Mar. (2000).
N. Oshima, T. M. Kojima, D. Dumitriu, A. Mohri , H.
Oyama, Y. Kanai, T . Kambara, Y. Nakai, M. Wada,and Y . Yamazaki: "Development of a slow positron
beam using a rare gas solid moderator" , 2000 Spring
Meet. of the Physical Society of Japan, Suit a , Mar.
(2000).
X . Diao, Y. Yoshida, K . Hayakawa, F . Shimura, T.
Kambara, and A. Iwase: "IR study on the V-O
pairs and oxygen-interstitials in CZ-Si irradiated by
3.5 GeV Xe", 2000 Spring Meet. of the Physical Society of Japan, Suita, Mar. (2000).
T. Ishida, T . Ise , T. Nogami, S. Ohira, 1. Watanabe,
and K. N agamine: "p'sR on Ar-CH= N-TEMPO
magnets (Ar=Biph,Ph,4-Py)", 78th National Meet .
Chemical Society of Japan, Funabashi, Mar. (2000) .
1. Shimamura: "Collision calculations for muonicfew-body systems", Workshop on Muon Catalyzed
Fusion Studies: Interaction between Theoreticaland Experimental Studies, (KEK) , Tsukuba, Mar.
(2000).
1. Watanabe, N. Wada, K . Awaga, S. Ohira, and K.
N agamine: "Dynamical and static internal fields infrustrated materials observed by the muon spin relaxation method" , Workshop on Frustration and Kiral Ordering for the Cerebration of the Foundationof The Kyoto Institute of Technology, Kyoto, Apr.
(2000).
Y. Koike , M. Akoshima, M. Aoyama, K. Nishimaki ,1. Watanabe, S. Ohira, W. Higemoto, and K.
Nagamine: " ~ anomaly and stripes in the Bi-2212
and Y-123 phases", Int. Workshop on Superconductivity, Structure and Property Relationship for
Applications of High-Temperature, Matsue, June
(2000).
Y. Kanai , D. Dumitriu, Y . Iwai , T. Kambara, T.
M. Kojima, Y. Morishita, Y. Nakai, H. Oyama,
N. Oshima, and Y. Yamazaki: "Present status ofslow highly-charged ion facility at RIKEN", 10th
Int. Conf. on the Physics of Highly Charged Ions
(HCI-2000) , (American Vacuum Society, Universityof California, and United States Department of Energy) , Berkeley, USA, July (2000) .
A. Itoh, T. Majima, H. Tsuchida, Y. Nakai, and T.
Kambara: "Charge-state dependence of C 60 - multifragmentation in collisions of 30 MeV Ne 2 - 9 + ions",
10th Int. Conf. on the Physics of Highly Charged
Ions (HCI-2000) , (American Vacuum Society, University of California, and United States Departmentof Energy) , Berkeley, USA , July (2000).
M. Huang, R. Hutton, Y. Zou, K . Ando, H. Oyama,and M. Huang: "The continuing saga of the Si-likeintercombinat ion lines in highly charged ions, Si-likerhodium", 10th Int. Conf. on the Physics of Highly
Charged Ions (HCI-2000) , (American Vacuum Soci-392

ety, University of California , and United States Department of Energy) , Berkeley, USA, July (2000).
R. Hutton, Y. Zou, K. Ando , and H. Oyama: "Optical transitions between spin-aligned levels of highly
charged Mg-like ions", 10th Int. Conf. on the Physics
of Highly Charged Ions (HCI-2000) , (American Vacuum Society, University of California, and UnitedStates Department of Energy), Berkeley, USA , July
(2000).
M. Hoshino, M. Kitajima, Y. Kanai, Y . Nakai, H.
Tanaka, and Y. Yamazaki: "Angular resolved energy gain spectroscopy to study of double electron
capture processes in very slow C 4 + -He collisions" ,10th Int. Conf. on the Physics of Highly Charged
Ions (HCI-2000) , (American Vacuum Society, University of California, and United States Departmentof Energy) , Berkeley, USA, July (2000) .
T. Azuma, T. Ito, Y. Takabayashi, K. Komaki, Y.
Yamazaki, E . Takada, and T. Murakami: "Resonant
coherent excitation of hydrogen-like Ar ions to then = 3 states" , 10th Int . Conf. on the Physics ofHighly Charged Ions (HCI-2000) , (American Vacuum Society, University of California, and UnitedStates Department of'Energy) , Berkeley, USA , July
(2000) .
Y. Zou, R. Hutton, S. Huldt , K. Ando , and H. Oyama:"Effects of foil aging properties on the intensities
of atomic transition lines following ion-foil interaction", 10th Int. Conf. on the Physics of Highly
Charged Ions (HCI-2000) , (American Vacuum Society, University of California, and United States Department of Energy) , Berkeley, USA, July (2000).
Y. Koike, M. Akoshima, M. Aoyama, K. Nishimaki,
T. Kawamata, T. Adachi, H. Noji, 1. Watanabe, S.
Ohira, W . Higemoto, K. Nagamine, H. Kimura, K .
Hirota, K. Yamada, and Y . Endoh: "Impurity effect on the stripes in the La-124, Bi-2212 and Y-123
phases" , Int. Symp. on Physics in Local Lattice Distortions (LLD2K), Tsukuba, July (2000).
K. Nagaya, Y. Teranishi, and H. Nakamura: "Newway of controlling molecular photo dissociation withuse of the complete reflection phenomenon" , 25th
Ann. Meet. of Society for Atomic Collision Research,
Okazaki, Aug. (2000) .
N. Oshima, T. M. Kojima, D. Dumitriu, A. Mohri,
H. Oyama, Y. Kanai, T. Kambara, Y. Nakai, M.
Wada, and Y . Yamazaki: "Research plans using
slow positron beam" , 25th Ann. Meet. of Society for
Atomic Collision Research, Okazaki, Aug. (2000) .
M. Hoshino, M. Kitajima, Y. Kanai , Y. Nakai, H.
Tanaka, and Y. Yamazaki: "Present status of very
low energy highly charged ion: Atom collision experiment", 25th Ann. Meet. of Society for Atomic
Collision Research , Okazaki, Aug. (2000) .
Y. Morishita, H. Torii, Y. Yamazaki, K. Kuroki, K.
Komaki , R. Hutton, K. Ando, K. Ishii, H. Masuda,and M. Sekiguchi: "Visible light spectroscopy of ·highly charged ions transmitted through a Ni microcapillary", 25th Ann. Meet. of Society for Atomic
Collision Research, Okazaki, Aug. (2000).
T. Azuma, T. Ito, Y. Takabayashi, K. Komaki , Y.
Yamazaki, E. Takada, and K. Murakami: "Resonant
coherent excitation of relativistic highly charged
ions: Excitation from the ground state of hydrogenlike ions to the n=3 states" , 25th Ann. Meet. of Society for Atomic Collision Research, Okazaki, Aug.
(2000).
T. Ito, Y. Takab ayas hi , T. Azuma, K. Komaki, Y.
Yamazaki, E . Takada, and K. Murakami: "Possible
application of resonant coherent excitation to highresolution atomic spectroscopy" , 25th Ann. Meet.
of Society for Atomic Collision Research, Okazaki,
Aug. (2000).
T. Nishimura and 1. Shimamura: "Calculation of
positronium formation cross section on positronhydrogen molecule collision", 25th Ann. Meet . of Society for Atomic Collision Research, Okazaki, Aug.
(2000).
Y. Iwai, S. Thuriez, R. Hutton, Y. Kanai, H. Oyama,
K. Ando, H. Masuda, K . Nishio, T. Azuma, K.
Komaki, and Y. Yamazaki: "Soft X-ray spectroscopy of slow highly charged ions through microcapillary" , 25th Ann. Meet. of Society for Atomic
Collision Research , Okazaki, Aug. (2000).
N. Suzuki, Y. Nagai, and T. Hyodo: "Vacancy
formation enregy of metals determined by using positron age-momentum correlation technique",12th Int. Conf. on Positron Annihilation (ICPA-12),
Mlinchen, Germany, Aug. (2000).
L. Wei, N. Suzuki, J. Kim, F. Saito, Y. Itoh, A. Goto,
T. Kurihara, Y. Nagashima, and T. Hyodo: "Slowpositron yields from a new type of moderator",
12th Int. Conf. on Positron Annihilation (ICPA-12) ,Mlinchen, Germany, Aug. (2000).
T. Nakatsukasa and K. Yabana: "Linear response in
the continuum" , Physics Division Seminar, (OakRidge National Laboratory), Oak Ridge, USA, Aug.
(2000).
N. Suzuki, Y . Nagai, Y. Itoh , A. Goto, and T. Hyodo:"Vacancy formation energy of metals determinedby using positron age-momentum correlation technique" , 55th Ann. Meet. of Physical Society ofJapan, Niigata, Sept. (2000).
T. Nakatsukasa and K. Yabana: "Real-space calculation method of continuum spectra" ,55th Ann. Meet.
of Physical Society of Japan, Niigata, Sept. (2000).
T. Nakamura, M. Wada, Y. Okada, I. Katayama,
S. Ohtani, and H. A. Shuessler: "Precision spectroscopy of the hyperfine structure of 9Be+ ion ina strong magnetic field using a combined linear ion
trap", 55th Ann. Meet. of Physical Society of Japan,
Niigata, Sept. (2000).
Y. Okada, L. Boesten, M. Wada, T. Nakamura, S.
Ohtani, and I. Katayama: "Development of a cryo-genic linear ion trap for spectroscopic application",
55th Ann. Meet. of Physical Society of Japan,
Niigata, Sept. (2000).
.
M. Hoshino, M. Kitajima, Y . Nakai, Y. Kanai, H.
Tanaka, and Y. Yamazaki: "Angular distribution measurements of electron capture processes
for X4 + (X=C,N,O)-He collision at low energy region" ,55th Ann. Meet. of Physical Society of Japan,
Niigata, Sept. (2000).
Y. Takabayashi, T . Ito, T. Azuma, K. Komaki, Y.
Yamazaki, E. Takada, and T. Murakami: "Convoy electron production with relativistic heavy ions:
Projectile charge state dependence" , 55th Ann.
Meet. of Physical Society of Japan, Niigata, Sept.
(2000).
T. Azuma, T. Ito, Y. Takabayashi, K. Komaki, Y .
Yamazaki, E. Takada, and T. Murakami: "Resonant
coherent excitation of hydrogen-like Ar ions to then = 3 states", 55th Ann. Meet. of Physical Societyof Japan, Niigata, Sept. (2000).
T. Ito, Y. Takabayashi, T. Azuma, K. Komaki , Y.
Yamazaki, E. Takada, and T. Murakami: "Resonant
coherent excitation of relativistic highly charged
ions II: Possibility of high resolution atomic spectroscopy", 55th Ann. Meet. of Physical Society ofJapan , Niigata, Sept. (2000).
T. Majima, A. Itoh, H. Tsuchida, Y. Nakai, and
T. Kambara: "Multiionization and multifragmentation processes of C 60 molecules induced by 30 Me V
Ne 2 - 9 + impacts: Projectile charge dependences",
55th Ann. Meet. of Physical Society of Japan,
Niigata, Sept. (2000).
A. Endo, K. Yoshiki Franzen, H. Torii, K. Komaki, andY. Yamazaki: "The development of a mini-EBIS using high-T c superconductors (II)", 55th Ann. Meet.
of Physical Society of Japan, Niigata, Sept. (2000).
T. Ichioka, H. Higaki , K. Yoshiki Franzen, Z. Wang, N.
Kuroda, M. Hori, N. Oshima, B. Ujbari, K. Kuroki,
A. Mohri, K. Komaki, and Y. Yamazaki: "Negativehydrogen ions and protons in the trap and their manipulation", 55th Ann. Meet. of Physical Society ofJapan, Niigata, Sept. (2000) .
Y. Iwai , S. Thuriez , R. Hutton, Y. Kanai, H. Oyama,
K. Ando, H. Masuda, K. Nishio, T. Azuma, K.
Komaki, and Y. Yamazaki: "High resolution soft
x-ray spectroscopy of highly charged ions throughNi micro capillary target (II)", 55th Ann. Meet. ofPhysical Society of Japan, Niigata, Sept. (2000).
T. Kambara, Y. Kanai, T. M. Kojima, Y. Nakai, Y.
Yamazaki, A. Yoneda, and K. Kageyama: "Acoustic
emission from solids irradiated by fast heavy ions(II)" , 55th Ann. Meet. of Physical Society of Japan,
Niigata, Sept. (2000).
Y. Nakai, T. Kambara, A. Itoh, H. Tsuchida, andY. Yamazaki: "Ionization and fragmentation of C60
by fast ion impact- Analysis of TOF spectra profile
of fullerene-like fragment ions", 55th Ann. Meet. of393

Physical Society of Japan, Niigata, Sept. (2000).
T. M. Kojima, N. Oshima, Y. Kanai , A. Mohri,
and Y. Yamazaki: "Development of an ion trap
for multi-charged ions cooled with cold positron
coolant", 55th Ann. Meet . of Physical Society ofJapan, Niigata, Sept. (2000).
N. Oshima, T. M. Kojima, D. Dumitriu, A. Mohri, H.
Oyama, Y. Kanai, T. Kambara, Y. Nakai , M. Wada,and Y. Yamazaki: "Development of a slow positron
beam using a rare gas solid moderator (II)", 55th
Ann. Meet. of Physical Society of Japan, Niigata,
Sept. (2000).
M. Takekawa and Y. Ichikawa: "Elastic scatteringof electron by OCS molecule", 55th Ann. Meet. ofPhysical Society of Japan, Niigata, Sept. (2000).
S. Morishima, H. J. Bang, Y. Hagio, T. Mochizuki,
T. Maruyama, K. Akimoto, M. Nomura, and E.
Vagi: "Concentration quenching of Eu related luminescence in Eu-doped GaN studied by EXAFS
analysis", 61st Autumn Meet. 2000 of The Japan
Society of Applied Physics, Sapporo, Sept. (2000).
H. J. Bang, S. Morishima, T. Maruyama, K. Akimoto,
M. Nomura, and E. Vagi: "Growth and characterization of Tb doped GaN", Int. Workshop on Nitride
Semiconductors (IWN2000), (The Japan Society ofApplied Physics) , Nagoya, Sept. (2000).
1. Shimamura: "Resonances in Coulomb few-body systerns", Int. Workshop on Resonances in Few-Body
Systems, (ATOMKI), Sarospatak, Hungary, Sept.
(2000).
N. Suzuki, H. Saito, Y. Nagai, T. Hyodo, H. Murakami,
M. Sano, Y. Itoh, S. A. Kuten, and 1. V. Vondarev:"Search for positronium quadrupole interaction in
crystalline solids", 43rd Symp. on Radiochemistry,
Wako , Oct. (2000).
Y. Yamazaki: "An ion beam to probe ions and an
ion beam to probe targets", Quantum Science andEngineering Center Symposium, Kyoto University,
Kyoto, Oct. (2000).
Y. Yamazaki: "Energy deposition mechanism withheavy particles: From slow highly charged ions torelativistic heavy ions" , RIKEN Symp. on Dynamics
of High-Energy and High-Density Excited ValenceElectrons in Matter, Wako, Oct. (2000).
T. Kambara: "Acoustic emission from solids irradiatedby fast heavy ions" , RIKEN Symp. on Dynamics
of High-Energy and High-Density Excited ValenceElectrons in Matter, Wako, Oct. (2000).
E. Vagi: "The study on the state of hydrogendissolved in metals by means of the channelling
method", Dai 11 Kai Suiso to Zairyou Kinou
Kyoudou Kenkyuukai, (The Japan Institute of Metals), Tokyo, Nov. (2000).
T. Kambara, Y. Kanai, T. M. Kojima, Y. Nakai,
A. Yoneda, Y. Yamazaki, and K. Kageyama: "Ultrasonic pulse from fast heavy-ion irradiation on
solids", 16th Int. Conf. on the Application of Ac-

394

celerators in Research and Industry (CAARI 2000),
Denton, USA , Nov. (2000).
N. Suzuki, Y. Nagai, Y. Itoh, A. Goto, and T.
Hyodo: "Vacancy formation energy of metals determined by using positron age-momentum correlation technique", Specialist Research Meet. on
Positron Beam Techniques for Science and Engineering, (Research Reactor Institute Kyoto University),
Kumatori, Nov. (2000).
N. Oshima, T. M. Kojima, D. Dumitriu, A. Mohri,
H. Oyama, Y. Kanai, T. Kambara, Y. Nakai, M.
Wada, and Y. Yamazaki: "Present status of thepositron cooling for highly charged ions", Specialist Research Meet. on Positron Beam Techniques for
Science and Engineering, (Research Reactor Institute, Kyoto University), Kumatori, Nov. (2000) .
H. Higaki , T. Ichioka, K. Yoshiki Franzen, N. Kuroda,
Z. Wang, S. Yoneda, H. Torii, K. Komaki, and Y.
Yamazaki: "Non-neutral plasma and production ofultra slow antiproton beam", 2nd Workshop on the
Theory of Antimatter Science by Use of Antiprotons
and 8th RIKEN Symp. on the Theory of Atomic andMolecular Processes: Antimatter Science by Use of
Antiprotons, Fujiyoshida, Dec. (2000).
1. Shimamura: "Influence of a laser field on the formation of antihydrogen", 2nd Workshop on the Theoryof Antimatter Science by Use of Antiprotons and
8th RIKEN Symp. on the Theory of Atomic andMolecular Processes: Antimatter Science by Use of
Antiprotons, Fujiyoshida, Dec. (2000).
T. Nakatsukasa and K. Yabana: "Calculations ofresponse function in the continuum", Computational Physics in Condensed Matter Research , (Institute for Solid State Physics, University of Tokyo) ,Kashiwa, Dec. (2000).
T. Ichioka, H. Higaki, K. Yoshiki Franzen, Z. Wang, N.
Kuroda, S. Yoneda, H. Torii, K. Komaki, M. Hori,
K. Kuroki, A. Mouri , and Y. Yamazaki: "ASACUSA
trap system for high intensity ultra slow antiprotonbeam" , Seminar of Atomic and Molecular Processesin Space, (The Institute of Space and Astronautical
Science) , Sagamihara, Dec. (2000).
4.

Radiochemistry, radiation chemistry, and radiatiqn biology

Y. Einaga, O. Sato, T. Iyoda, Y. Kobayashi, F. Ambe,
K. Hashimoto, and A. Fujishima: "Characterization of cobalt iron cyanide by 57Fe Mossbauer Spectroscopy", Int. Conf. on the Applications of the
Mossbauer Effect 1997, Rio de Janeiro, Brazil, Sept.
(1997).
C. H. Bae, T. Abe, T. Matsuyama, T. Nakano, andS. Yoshida: "Effect of heavy-ion beam irradiation
on mutation induction in plants at pollination stage(III)", 93rd Congr. of the Breeding Society of Japan,
Yokohama, Mar. (1998).

S. Sharma, J. Kaneko , and N. Ito: "Stimulated emission and exciton complex formation in some insulator crystals irradiated by heavy-ions", 7th Workshop on Fast Ion-Atom Collisions, Debrecen, Hungary, Sept. (1998).
K. Ushida, K. Ishioka, S. Hishita, K. G. Nakamura,and M. Kitajima: "Acceleration of dephasing of coherent phonons induced by ion implantation", 1998
Asian-Pacific Forum on Science and Technology:
Optical Probing and Creation of Advanced Photoactive Materials, (Japan Advanced Institute of
Science and Technology, Hokuriku), Tatsunokuchi,
Nov. (1998).
K. Ushida, K. Ishioka, S. Hishita, K. G. Nakamura,and M. Kitajima: "Effect of disorders artificiallygenerated by ion beam irradiation on the dephasing of coherent phonons", 1st Int. Symp. on Atomic
Scale Processing and Novel Properties in N anoscopic
Materials, (The Institute of Scientific and Industrial Research CaE, Osaka University), Suita, Nov.
(1998).
T. Matsuyama, T. Abe, C. H. Bae, T. Nakano,
T. Asami, and S. Yoshida: "RLGS analysis inplant genome", Ann. Meet. of Japan Society
for Bioscience, Biotechnology, and Agrochemistry,
Fukuoka, Mar. (1999).
Y. Nose, S. Enomoto, S. Ambe, F. Ambe, and 1.
Yamaguchi: "Multitracer study on biosorption ofvarious trace elements in yeast Saccharomyces cerevisiae", RIKEN Symp. on Bio-Trace Elements '99,
Wako, Mar. (1999).
C. H. Bae, T. Abe, N. Nagata, T. Matsuyama, T.
Nakano, H.-Y. Lee, and S. Yoshida: "A chlorophyll deficient mutant that has an altered amount ofchloroplast genes", 1999 Korea-Japan Joint Symp.:
New Approaches to Understand Gene Function in
Plants and Application to Plant Biotechnology,(Seoul National University), Seoul, Korea, July
(1999).
S. Sharma and J. Kaneko: "Extremely short-lived
track luminescence of ion irradiated insulator crystals", 1Oth Int. Conf. on Radiation effects in Insulators, Jena, Germany, July (1999).
K. Kimura, S. Sharma, and J. Kaneko: "New 100 pslived uv luminescence of ion track in wide band-gap
crystals" ,21st Int. Conf. on the Physics of Electronicand Atomic Collisions (XXI-ICPEAC), Sendai, July
(1999).
S. Sharma and J. Kaneko: "A new 100 ps-lived luminescence of ion tracks in insulator crystals", 18th
Int. Conf. on Atomic Collisions in Solids, Odense,
Denmark, Aug. (1999).
H. Tamano , S. Enomoto, E. Igasaki, N. Oku, N. Itoh,K. Tanaka, and A. Takeda: "Tumor growth after subcutaneous transplantation is affected by hepatic zinc metallothionein level", Metallothionein 99,(Osaka University), Osaka, Nov. (1999).

Y. Nose, S. Ambe, S. Enomoto, T. Arie, T. Soshi, and1. Yamaguchi: "Uptake and distribution of various
radionuclides in soybean", RIKEN Symp. on BioTrace Elements '99.12 , Wako, Dec. (1999).
H. Tamano, S. Enomoto, and A. Takeda: "Tumor andtrace elements", RIKEN Symp. on Bio-Trace Elements '99 .12, Wako, Dec. (1999).
F. Yatagai, T. Nomi, and M. Kusakabe: "Mutation induction by heavy-ion irradiation of gpt~ transgenic
mouse", (The Institute of Space and Astronautical
Science), Sagamihara, Jan. (2000).
Y. Kobayashi:"In-beam Mossbauer studies of
57Fe( f - 57 Mn) atoms via projectile fragmentationand implantation", RIKEN Symp. on Studies on
Condensed Matter Physics, Atomic Physics, Hyperfine Interactions and Biomedical Sciences Using
RIKEN Accelerators, Wako, Jan. (2000).
F. Yatagai: "Biological effect of p53 after the heavyion exposure", Int. Workshop on Dose-Effect Relationship of Particle Radiations, (National Instituteof Radiological Sciences), Chiba, Feb. (2000).
M. Hase, K. Ishioka, K. Ushida, and M. Kitajima:"Dephasing of coherent phonons induced by latticedefects in thin film of bismuth", 28th Workshop of
the Surface Science Society of Japan, Tsukuba, Feb.
(2000).
Y. Yoshida, A. Saeki, T. Kozawa, S. Seki, K. Ushida,
Y. Numata, and S. Tagawa: "Geminate ion recombination in liquid alkane studied by subpicosecond andpicosecond pulse radiolysis", 78th National Meet.
Chemical Society of Japan, Funabashi, Mar. (2000).
Y. Kobayashi, A. Yoshida, K. M. Kubo, Y. Yamada,and F. Ambe: "Characterization of Fe atoms bymeans of 57Mn beam and the in-beam Mossbauer
technique", 78th National Meet. Chemical Societyof Japan, Funabashi, Mar. (2000).
Y. Kobayashi, A. Yoshida, K. M. Kubo, and Y.
Yamada: "In-beam Mossbauer studies on valence
states of 57Fe ions decayed from 57Mn" , Work on Science with Low-energy Radioactive Nuclear Beams
2000, (High Energy Acclerarater Research Organization), Tanashi, Mar. (2000).
Y. Konomi, T. Abe, F. Sugawara, and S. Yoshida:"Salt resistant mutation using heavy-ion beams",
2000 Ann. Meet. of Japan Society for Bioscience,
Biotechnology, and Agrochemistry, Tokyo, Apr.
(2000) .
K. Tokuhara, T. Abe, K. Miyoshi, and S. Yoshida:"Effects of heavy-ion beam irradiation on PLB development in several orchids", 97th Congr. of the
Breeding Society of Japan, Tsukuba, Apr. (2000).
H. Tsujimoto, T. Yamada, and T. Abe: "Breakage of wheat chromosomes by irradiation of heavyion beam", 97th Congr. of the Breeding Society ofJapan, Tsukuba, Apr. (2000).
A. Yoshiki, N. Hiraiwa, C. Yoshida-Noro, N.
Fukunishi, M. Kase, Y. Yano, and M. Kusakabe:395

"A novel method for production of mutant mice byheavy ion beams", 33rd Ann. Meet. of the JapaneseSociety of Developmental Biologists, Kochi, May(2000).
H. Tamano, S. Enomoto, E. Igasaki, N. Oku, N. Itoh,K. Tanaka, and A. Takeda: "Tumor growth after
subcutaneous injection is affected by hepatic zincmetallothionein level", 6th Int. Symp. on Metal Ions
in Biology and Medicine, (Armed Forces Institute of
Pathology), Puerto Rico, USA, May (2000).
H. Tamano, S. Enomoto, and A. Takeda: "Zinc-65
imaging of rat brain tumors", 11th Ann. Meet. of
the Japan Society for Biomedical Research on Trace
Elements, Nagoya, June (2000).
S. Enomoto, R. Hirunuma, H. Tamano, and Y.
Kawamura: "Transfer of various elements from theplacenta to the fetus", 11th Ann. Meet. of the Japan
Society for Biomedical Research on Trace Elements,
Nagoya, June (2000).
K. Matsumoto, R. Hirunuma, S. Enomoto, and K.
Endo: "Contents and uptakes of various elements
in Se-deficient rat liver cell-fractions", 11th Ann.
Meet. of the Japan Society for Biomedical Researchon Trace Elements, Nagoya, June (2000).
Y. Taroda, R. Amano, and S. Enomoto: "Concentration and behavior of Mn in the brain of young mice" ,11th Ann. Meet. of the Japan Society for Biomedical
Research on Trace Elements, Nagoya, June (2000).
K. Ushida, M. Hase, K. Ishioka, and M. Kitajima:"The evaluation of defects formed in solids on ion
irradiation as probed by coherent phonon spectroscopy", Gordon Research Conf. on Radiation
Chemistry, Plymouth, USA, June (2000).
T. Matsuyama, T. Abe, C.-H. Bae, R. Kiuchi, T.
Nakano, T. Asami, and S. Yoshida: "Plant genome
DNA analysis by two-dimensional gel elecrophoresis", 2000 Japan-Korea Joint Symp. of Plant Science on Plant Responses to Environments: Molecular Mechanisms and Applications to Biotechnology,(The Botanical Society of Japan), Shizuoka, July
(2000).
T. Abe, H. Takahashi, C.-H. Bae, N. Nagata, T.
Matsuyama, and S. Yoshida: "Physiological responses of normal and albino tobacco to clomazone treatment" , 2000 PGRSA/ JSCRP Ann. Meet.,(Plant Growth Regulation Society of America),
Kailua-Kona, USA, July (2000).
T. Abe, T. Matsuyama, N. Fukunishi, S. Sekido, S.
Yoshida, and 1. Yamaguchi: "An effective mutation
method for plants using heavy-ion beams (II)", 18th
Ann. Meet. and Symp. of Japanese Society for Plant
Cell and Molecular Biology, Shizuoka, July (2000).
F. Saito, L. Wei, N. Suzuki, J. Kim, Y. Itoh, A.
Goto, T. Kurihara, Y. Nagashima, and T. Byodo:"Separation of 18F for the radio-pharmaceuticals of
PET from 180-water by electro-deposition", 37th
Ann. Meet. on Radioisotopes in the Physical Sci-

396

ence and Industries, (Japan Radioisotope Association), Tokyo, July (2000).
T. Abe: "Salt tolerant mutants obtained by ion beamirradiation" ,37th Gamma Field Symp., (MAFF, Institute of Radiation Breeding NIAR), Mito, July
(2000).
M. Hase, K. Ishioka, M. Kitajima, and K. Ushida:"Effect of lattice defects on LO phonon-plasmon
coupled modes in n-GaAs", 12th Int. Conf. on Ultrafast Phenomena, (Optical Society of America),
Charleston, USA, July (2000).
T. Abe: "EffeGt of heavy-ion beam irradiation on mutation induction in plants.", 6th VIBRC Colloq.
for Young Scientist, (Iwate Biotechnology ResearchCenter), Kitakami, July (2000).
F. Saito, N. Suzuki, J. Kim, L. Wei, Y. Itoh, A. Goto,
T. Kurihara, Y. Nagashima, and T. Hyodo: ,,18F
source for a slow positron beam", 12th Int. Conf.
on Positron Annihilation (ICPA-12), Miinchen, Germany, Aug. (2000).
C. Egawa, Y. Takahashi, S. Enomoto, R . Hirunuma,
and H. Shimizu: "Multitracer study on the diffusion of various trace elements in a granite", 2000
Ann. Meet. of the Geochemical Society of Japan,
Yamagata, Sept. (2000).
F. Saito, 1. Fujiwara, N. Suzuki, J. Kim, L. Wei, Y.
Nagashima, T. Kurihara, Y. Itoh, A. Goto, andT. Hyodo: "Electro-deposition of 18p for a slow
positron beam source and recovery of 180-water insynthesis of [18F]FDG", 43rd Meet. of Radiation
Chemical Society of Japan, Wako, Sept. (2000).
M. Base, K. Ishioka, K. Ushida, and M. Kitajima:"Annihilation of coherent LO phonon-plasmon coupled modes by lattice defects in n-GaAs", 25th Int.
Conf. on the Physics of Semiconductors (ICPS 25),
(IUPAP, The Science Council of Japan, The Physical Society of Japan, and The Japan Society of Applied Physics), Osaka, Sept. (2000).
M. Kitajima, M. Base, K. Ishioka, and K. Ushida:"Dephasing of coherent phonons by lattice defects" ,Koushi Kekkan Forum, (The Physical Society ofJapan), Niigata, Sept. (2000).
Y. Kobayashi, K. M. Kubo, Y. Yamada, A. Yoshida,
H. Ogawa, B. Ueno, K. Asahi, and F. Ambe: "Inbeam Mossbauer studides on chemical states of 57Fe
atoms decaying from 57Mn" , 44th Symp. on Radiochemistry, Kobe, Sept. (2000).
C. Egawa, Y. Takahashi, S. Enomoto, R. Hirunuma,
and B. Shimizu: "Multitracer study on the diffusionof various elements in a granite", 44th Symp. on
Radiochemistry, Kobe, Sept. (2000).
M. Base, K. Ishioka, K. Ushida, and M. Kitajima:"Electron-phonon dynamics in ion-implanted semiconductors by using coherent phonon spectroscopy",
43rd Meet. of Radiation Chemical Society of Japan,
Wako, Oct. (2000) .
A. Saeki, T. Kozawa, S. Seki, K. Ushida, Y. Yoshida,

and S. Tagawa: "Study on geminate ion recombination in n-dodecane using subpicosecond pulse radiolysis", 43rd Meet. of Radiation Chemical Society ofJapan, Wako, Oct. (2000).
F. Yatagai, T. Kurobe, T. Nomi, M. Kusakabe, K.
Masumura, A. Yoshiki, H. Yamaguchi, K. Kuniya,
F. Hanaoka, and Y. Yano: "Mutation induction by
heavy ion irradiation of gpt ~ transgenic mice", 14th
Ann. Meet. of Japanese Society for Biological Sciences in Space, Fukushima, Oct. (2000).
1. Honda, M. Wada, T. Abe, T. Asami , and S. Yoshida:"Application of heavy-ion bombardment to mutate
wheat and barley", 2000 Int. Workshop Molecular
Plant Breeding and Utilization of Genetic Resources,(STA, JISTEC , and MAFF), Tsukuba, Nov. (2000).
1. Honda, M. Wada, T. Abe, T. Asami, and S. Yoshida:"A novel barley mutant induced by heavy ion bombardment", 35th Ann. Meet. of the Society for theChemical Regulation of Plants, Wako, Nov. (2000).
H. Nagase, A. Yoshiki , C. Yoshida-Noro, and M.
Kusakabe: "Possible use of somatic and germ-line
mutation induced by heavy ion beam (HIB) irradiation in mouse carcinogenesis models", 14th Int.
Mouse Genome Conf. (IMGC 2000), Narita, Nov.
(2000).
A. Yoshiki, C. Yoshida-Noro, H. Nagase, N. Hiraiwa,
A. Kogiso, T. Masuda, and M. Kusakabe: "A novel
strategy for mutagenesis in the mouse: Heavy ion
beams and fetal phenotype screening (II)", 14th Int.
Mouse Genome Conf. (IMGC 2000) , Narita, Nov.
(2000).
M. Kusakabe, A. Yoshiki, N. Hiraiwa, F. Ike, C.
Yoshida-Noro, H. Nagase , and Y. Yano: "A novel
strategy for mutagenesis in the mouse: Heavy ion
beams and fetal phenotype screening (II)", 14th Int.
Mouse Genome Conf. (IMGC 2000) , Narita, Nov.
(2000).
C. Yoshida-Noro, H. Nagase, A. Yoshiki, and M.
Kusakabe: "A novel strategy for mutagenesis in
the mouse: Heavy ion beams and fetal phenotype
screening (III)", 14th Int. Mouse Genome Conf.
(IMGC 2000) , Narita, Nov. (2000).
F. Saito, L. Wei, N. Suzuki, J. Kim, Y. Itoh, A. Goto,
T. Kurihara, Y. Nagashima, and T. Hyodo: "Development and application of spin polarized positron
beams" , Specialist Res. Meet. on Positron BeamTechniques and Condensed Matter, (Research Reactor Institute, Kyoto University), Osaka, Nov. (2000).
F. Saito, 1. Fujiwara, N. Suzuki, J. Kim, L. Wei, Y.
Itoh, A. Goto, T. Kurihara, Y. Nagashima, andT. Hyodo: "Electro-deposited 18F source for slow
positron beam", 11th Symp. on Beam Engineering ofAdvanced Material Syntheses, Tokyo, Nov. (2000).
H. Yasui, T. Takino, J. Fugono , R. Matsushita, J.
Takada, R. Hirunuma, S. Enomoto, and H. Sakurai:"Metallokinetic analysis of blood disposition andbiodistribution of vanadyl complexes in rats", 2000

Int . Chemical Congr. of Pacific Basin Societies(PACIFICHEM 2000), Honolulu, USA, Dec. (2000).
S. Morimoto, T. Kato, M. Izumi, N. Fukunishi , M.
Honma, F. Hanaoka, and F. Yatagai: "Cellular responses after low-dose exposure to heavy ions" , 23rd
Ann. Meet. of Japanese Society of Molecular Biology, Kobe, Dec. (2000).
C. Yoshida-Noro, A. Yoshiki, H. Nagase, N. Hiraiwa,
F. Ike , and M. Kusakabe: "A novel approach for mutagenesis in t he mouse: Heavy ion beams and fetal
phenotype screening", 23rd Ann. Meet. of JapaneseSociety of Molecular Biology, Kobe, Dec. (2000).
T. Soshi, T. Arie, and 1. Yamaguchi: "Influence ofFusarium on the uptake of radionuclides by tomato" ,RIKEN Symp. on Bio-Trace Elements 2000, Wako,
Dec. (2000).

5.

Material analysis

T. Sugimura, J. Kawai, K. Maeda, A. Fukushima, andS. Shin: "F K-edge X-ray absorption spectroscopy
for chemical state analysis", Eur. Conf. on Energy
Dispersive X-Ray Spectrometry 2000, (Universityof Mining and Metallurgy) , Krakow, Poland , June
(2000).
N. Handa, O. Nureki, K. Kurimoto, S. Fukai , 1.
Kim, H. Sakamoto, Y. Shimura, Y. Muto, and S.
Yokoyama: "Crystal structure of the Sex-lethal protein in complex with the transformer mRNA precursor at 1. 7 A resolution", 2nd Ann. Meet. of the
RNA Society of Japan, Yokohama, July (2000).
T. Sugimura, J. Kawai, K. Maeda, A. Fukushima, S.
Shin, M. Motoyama, and T. Nakajima: "F K-edge
soft X-ray absorption spectroscopy", 36th Meet. for
X-ray Chemical Analysis Japan, (Discussion Groupof X-Ray Analysis, The Japan Society for Analytical
Chemistry) , Neyagawa, Nov. (2000) .
K. Maeda, K. Ogiwara, H. Hamanaka, K. Hasegawa,and G. Ito: "Mini position-sensitive spectrometerwith a limit ted diffraction angle range designed forchemical analysis of adjacent elements", 17th PIXE
Symp. , Hakodate, Nov. (2000).

6.

RIKEN-BNL Collaboration on Spin Physics Program

Y. Nara: " Par~on cascade description of nuclear col:"lisions at RHIC", Nihon Genshiryoku Kenkyujyo
Kenkyukai Dai 2 Kai Kyokugen Jyouken ni okeru
Hadron Kagaku, Tokaimura, Jan. (2000).
Y. N ara: "Parton cascade prediction of baryon distribution in ultra-relativistic heavy ion collisions" , 3rdCatania Relativisitc Ion Studies (CRIS 2000), (Italian National Institute of Nuclear Physics (INFN)
and the University of Catania) , Acicastello, Italy,
May (2000).
D. Boer: "Transversely polarized A production",
7th Conf. on Intersections of Particle and Nuclear

397

Physics (CIPANP2000) , Quebec City, Canada, May(2000).
Y. Nara: "Hadron observables from hadronic transport model with jet production at RHIC", Structureof Nucleus at the Dawn of the Century (Bologna
2000) , (Italian National Institute of Nuclear Physics(INFN) and The University of Bologna) , Bologna,
Italy, May (2000).
Y. Aoki, A. Ali Khan, S. Aoki, R. Burkhalter, S.
Ejiri, M. Fukugita, S. Hashimoto, N. Ishizuka, Y.
Iwasaki, Taku Izubuchi, K. Kanaya, T. Kaneko,
Y. Kuramashi, T. Manke, K. Nagai , J. Noaki, M.

398

o kawa , H. Shanahan, Y. Taniguchi, A. Ukawa,and T. Yoshie: "Chiral properties of domain-wallquarks in quenched QCD", Int. School of Subnuclear Physics: 38th Course, Theory and Experiment
Heading for New Physics , (EMFCSC) , Erice, Italy,
Aug. (2000).
K. Suzuki and K. Itakura: "Constraints on color
dipole-nuclear cross section from diffractive heavy
quarkonium production" , Int. Workshop on Diffraction in High-Energy Physics (Diffraction 2000) ,(U niversitadella Calabria U niversitadi Torino) , Centraro, Italy, Sept. (2000).

x. LIST OF SYMPOSIA(Jan.- Dec. 2000)
1) RIKEN Symp. on Present Status of Nuclear Fusion Research and Muon Catalyzed Fusion
6 Jan. , Wako, Muon Science Lab. , RIKEN
2) 10th RIKEN Winter School on Nuclear Physics with Electromagnetic Probes at RIKEN RI-Beam Factory:
Unstable Nuclei and Hadrons
9- 14 Jan., Akita, RI Beam Science Lab. , RIKEN
3) Workshop on J et Tagets at RHIC
26- 28 Jan. , New York, USA, RIKEN BNL Research Center
4) RIKEN Symp. on Studies on Condensed Matter Physics, Atomic Physics, Hyperfine Interactions, andBiomedical Science Using RIKEN Accelerators
31 Jan., Wako, Cellular Physiology Lab., Muon Science Lab., Applied Nuclear Physics Lab., Atomic Physics
Lab. , Cyclotron Center, RIKEN
5) RIKEN Workshop on Nuclear Structure and Reaction for the 21st Century
4- 6 Feb. , Wako, Cyclotron Center, RIKEN
6) RIKEN Int. Workshop on Shell Model 2000
5- 8 Mar., Wako, Cyclotron Center, RIKEN
7) Event Generator for RHIC Spin Physics III: Towards Precision Spin Physics at RHIC
6- 17 Mar. , New York, USA, RIKEN BNL Research Center
8) Predictions and Uncertainties for RHIC Spin Physics
6- 31 Mar., New York, USA, RIKEN BNL Research Center
9) Workshop on Muon Catalyzed Fusion Studies: Interaction between Theoretical and Experimental Studies
21- 23 Mar. , Tsukuba, Muon Science Lab. , KEK-MSL and RIKEN-MUON
10) RIKEN Symp. on Scientific Research Using Tritium and Related Engineering
15-16 May, Wako, Muon Science Lab., RIKEN
11) RIKEN Symp. on The Development and Application of Neutron Optics
17- 18 May, Wako, Image Information Div., RIKEN
12) Workshop on Physics at RI Beam Factory: The First Experiments
21 June, Wako, RI Beam Science Lab., RIKEN
13) eRHIC Summer Meeting at BNL
26 June- 14 July, New York, USA , RIKEN BNL Research Center
14) Spin Physics Topics to be Pursued at EPIC and eRHIC
27 June, New York, USA, RIKEN BNL Research Center
15) Equilibrium and Non-Equilibrium Aspects of Hot, Dense QCD
17- 30 July, New York, USA, RIKEN BNL Research Center16) Meeting on Year-2 RHIC Spin Running
3 Aug. , New York, USA, RIKEN BNL Research Center17) RIKEN Workshop on Cluster Structure of Nuclei: Tensor Force and Nuclear Structure
19-22 Aug., Wako, RI Beam Science Lab. , RIKEN

399

18) CNSjRIKEN Workshop on Physics with Low Energy RIB
23- 25 Aug. , Wako, Applied Nuclear Physics Lab., RI Beam Science Lab. , Radiation Lab. , CNSjRIKEN
19) Future Transversity Measurements
1.8- 20 Sept., New York, USA, RIKEN BNL Research Center
20) RIKEN Symp. on Dynamics of High-Energy and High-Density Excited Valence Electrons in Matter
6 Oct., Wako, Beam Technology Div. , RIKEN21) RIKEN Symp. on Recent Topics on Magnetic Correlations in High Tc Superconductors
11 Oct., Wako, Muon Science Lab. , RIKEN
22) Int. Workshop on Polarized Partons at High Q2 Region in Kyoto
13-14 Oct. , Kyoto, RIKEN BNL Research Center
23) Int. Spin Physics Symp. on SPIN2000 in Osaka
16- 21 Oct., Osaka, RIKEN BNL Research Center24) RIKEN Conf. on RIBOO: Int. Symp. on Perspectives in Physics with Radioactive Isotope Beams 2000
13- 16 Nov., Hayama, Applied Nuclear Physics Lab., RI Beam Science Lab. , Radiation Lab., RIKENjCNS25) RIKEN-GSI Workshop on Electron-(Unstable) Nucleus Collider
17- 18 Nov., Wako, RI Beam Science Lab., Beam Physics and Engineering Lab. , RIKEN
26) RIKEN-RCNP Workshop on Exotics in Hadron Many Body System
22- 24 Nov., Nara, RI Beam Science Lab. , RIKEN27) Workshop on Rapid Stochastic Cooling23- 24 Nov. , Minakami, Beam Physics and Engineering Lab. , RIKEN28) RIKEN Symp. on Bio-Trace Elements 2000
1 Dec., Wako, Cyclotron Center, RIKEN
29) 8th RIKEN Symp. on The Theory of Atomic and Molecular Processes: Antimatter Science Using Antiprotons
15- 17 Dec., Fujiyoshida, Atomic Physics Lab., RIKEN

400

XI. LIST OF SEMINARS(Jan.- Dec. 2000)
Radiation Lab., RI Beam Science Lab., Applied Nuclear Physics Lab., and Beam Technology Div.

1) P. Moller, Los Alamos National Laboratory(USA) , 11 Jan.
"Barriers for fission and fusion in the heavyelement region"2) M. Smith, Oak Ridge National Laboratory(USA) , 24 Jan.
"New radioactive beam measurements and theoretical calculations relevant for novae and X-ray
bursters"
3)

J. Wallenius, KTH (Sweden) , 26 Jan.
"Accelerator driven systems for transmutation oflong lived nuclear waste"4) M. G. Itkis, Flerov Laboratory of Nuclear Reac-"A model for the 3He( d~ p )4He reaction at intermediate energies"
12) N. V. Giai, Institut de Physique Nucleaire(France) , 17 Mar.
"Microscopic description of (p, p') reactions on
unstable oxygen, sulfur and argon isotopes"

13) F . Iachello, Yale University (USA) , 12 Apr.
"The discovery of supersymmetry in nuclei"
14) Y. Akaishi, KEK (Tsukuba), 28 Apr.
"Coherent lambda-sigma coupling in light hypernuclei"15) S. Kuyucak, Australian National University (Australia), 10 May"Description of quadrupole-oct up ole collectivity
in boson models"

tions, JINR (Russia), 27 Jan.
"Fission of heavy and superheavy nuclei at low
excitation energies"16) K. Kazunori, YITP, Kyoto University (Kyoto) , 11May
"Standard theory of big-bang nucleosynthesis andpresent observation of light elements"

5) S. Amari, Washington University (USA), 28 Jan.
"Abundance analysis for presolar grains found inmeteorites: Nucleosynthesis studied with isotopic. anomaly"17) T. Muto, Chiba Institute of Technology(Narashino) , 15 May"Nuclear experiment on the giant Gamow-Teller
state and pion condensation"

6) A. Gorine, Institute of High Energy Physics(IHEP, Protvino) (Russia) , 10 Feb.
"Recent development of fiber detectors using
position-sensitive pmt"

18) C. Samanta, Saha Institute of Nuclear Physics(India) , 7 June
"Proton elastic scattering from 4,6,8He and6,7,9,11 Li"

7) L. Schroeder, LBNL (USA) , 16 Feb.
"Nuclear physics at the Berkeley Lab. "19) M. Thoennessen, MSU (USA) , 8 June
"Structure of the particle-unbound nuclei 7,9He
and lOLi"

8) A. B. Kurepin, Institute for Nuclear Research,
Russian Academy of Sciences (Russia) , 22 Feb.
"Possible observation of a phase transition toquark-gluon plasma in nuclear matter"20) H. Utsunomiya, Konan University (Kobe), 16
June"Photodisintegration of 9Be for nuclear astrophysics"

9) U. Garg, University of Notre-Dame (USA) , 24
Feb.
"Additivity of incremental alignment in superdeformation bands in the A 150 region"21) T. Aumann, GSI (Germany), 19 June
"Electromagnetic excitation of relativistic secondary beams"10) C. Baktash, Oak Ridge National Laboratory(USA), 13 Mar.
"Research opportunities with radioactive ion
beams at ORNL"

22) P. von Neumann-Cosel, Institut fur Kernphysik,
TU Darmstadt (Germany), 19 June
"Electron scattering and elementary excitation
modes of nuclei"11) H. Kamada, Institut fUr Theoretische Physik II
Ruhr-UniversiUit Bochum (Germany) , 16 Mar.

23) A. Mengoni, ENEA-Bologna and INFN-Bologna(Italy) , 20 June401

"Nuclear Physics and Astrophysics at CERN-n
TOF"24) N. Kalantar-Nayestanaki, KVI Groningen (TheNether lands), 23 June
"Probing
few-bodysystems
withBremsstrahlung"25) S. Shlomo, Cyclotron Institute, Texas A&M University (USA), 7 July
"Microscopic calculation of excitation of isoscalar
giant resonances by inelastic alpha scattering"26) G. Colo', Universita' degli Studi (Italy), 12 July
"Giant resonances in stable and unstable nuclei"27) H. Nakada, Chiba University (Chiba), 13 July
"Microscopic calculation of nuclear level densities
applying the shell model Monte Carlo method"28) Y. Miake, Institute of Physics, University ofTsukuba (Tsukuba), 18 July
"QGP formation and collective flow in high energy heavy ion collisions"29) K. Chmielewski, Institut fUr Theoretische Physik,
Universitat Hannover (Germany), 28 Aug.
"Elastic and inelastic neutron-deuteron scatteringwith .6.-isobar excitation"30) E. Ideguchi, Royal Institute of Technology (Sweden), 30 Aug.
"'Enhanced' superdeformation in 91Tc"
31) S. WenQing, Shanghai Institute of Nuclear Research, Chinese Academy of Science (China), 11
Sept.
"Research on isospin effect of projectile fragmentation reaction and BUU calculation of total reaction cross section"35) J. Tojo, Kyoto University (Kyoto), 25 Oct.
"Measurement of the analyzing power for protoncarbon elastic scattering in the Coulomb-nuclear
interference region with a 22 Ge V / c polarized proton beam"36) Ch. Stoyanov, Institute for Nuclear Research andNuclear Energy (Bulgaria), 6 Nov.
"Microscopic description of newly discovered
mixed symmetry states"37) M. Zhukov, Chalmers University of Technology(Sweden), 9 Nov.
"Can we discuss a proton halo in 8 B 7"38) H. Koura, Waseda University (Tokyo), 27 Nov.
"New mass formula and suggested properties of
instable nuclei"39) A. 1. Malakhov, JINR (Russia), 11 Dec.
"Some results and research program of Laboratory of High Energies (JINR, Dubna)"40) A. P. Kobushkin, Bogolyubov Institute for Theoretical Physics (Ukraine), 11 Dec.
"Deuteron spin structure at short distances fromexperiments with polarized deuteron beams"41) P. Moller, Los Alamos National Laboratory(USA), 28 Dec.
"New results from calculations of fission and fusion barriers in five-dimensional, multi-milliongrid-point deformation spaces"42) Y. Hasegawa, Atominstitut (Austria), 28 Dec.
"Quantum mechanics from interference experiment"

Atomic Physics Lab.

1) O. Jagutzki, IKF , Universitat Frankfurt (Ger32) P. K. Sahu, Hokkaido University (Sapporo), 2
Oct.
"Nuclear equation of state and its application to
heavy-ion collisions and neutron star"many), 2 Feb.
"Position and time resolved MCP read-out withdelay-line anodes: Novel techniques, applications
and future developments"

33) S. WenQing, Shanghai Institute of Nuclear Research, Chinese Academy of Science (China), 4
Oct.
"Program for RIB physics and nuclear astrophysics in China and preliminary plan of Shanghai laser electron gamma source"2) T. Hirota, University of Tokyo (Tokyo), 16 Feb.
"Chemical composition and evolution of mattersin the core region of dark nebulas"34) Y. A. Plis, Joint Institute for Nuclear Research(Russia), 11 Oct.
"The new possibilities for polarized ion beam production"4023) E. Lindroth, Stockholm University (Sweden), 6Mar.
"What is known and what is not known on thehigh resolution spectroscopy of few body high z
system"4) C. C. Havener, Oak Ridge National Laboratory

(USA), 21 Mar.
"Low energy ion-atom collisions using merged
beams"
5) M. Inokuti, Argonne National Laboratory (USA),
28 Mar.
"Dielectric-response function: Data analysis withthe use of sum rules and dispersion relations"6) J. Haynes, Institute of Physics (UK), 29 Mar.
"The future of physics communication"7) T. Matsumoto , ERATO , JST (Tsukuba), 19 Apr.
"Negative muon capture processes in hydrogenterminated silicon nanocrystal"8) A. Czasch, IKF, Universitat Frankfurt (Germany) , 20 Apr.
"Fragmentation of diatomic molecules in slow
scattering processes".9) H. A. Schuessler, Texas A&M University (USA) ,21 Apr.
"Ultra-sensitive trace detection by laser spectroscopy"10) T. Kuwamoto, Kyoto University (Kyoto) , 28 Apr.
"Search for permanent electric dipole momentwith cooled Yb atoms"
11) Y. Fukuda, University of Tokyo (Tokyo), 1 May"VUV spectroscopy of rare gas dimers: Ion coretransfer in high Rydberg states"
12) L. G. Christophorou, National Institute of Standards and Technology (USA), 25 May"Electron interactions with excited atoms andmolecules"
13) X.-M. Tong, Cold Trapped Ion Project, ICORP,
JST (Chofu), 21 July
"Density functional theory with optimized effective potential: An application to energy structureof hollow atoms and ions"14) S. Hasegawa, Institute of Space and Astronautical
Science (Sagamihara), 23 Aug.
"Acceleration of submicron and micron particles
by an electrostatic accelerator"17) H. A. Schuessler, Texas A&M University (USA) ,4 Dec.
"Nonlinear properties of laser-generated giant
surface acoustic wave pulses in solid materials"18) E. D. Donets, JINR (Russia) , 18 Dec.
"N uclear and atomic researches with an ion
trap apparatus, using dense electron beams andstrings: Results and project proposals"
RIBF Project Office, Beam Physics and Engineering
Lab ., Beam Dynamics Div., and Beam Technology
Div.

1) M. Xiao , University of Tokyo (Tokyo), 10 Feb.
"Spin dynamics of polarized proton beams in relativistic heavy ion collider (RHIC)"
2) R. Jameson, LANL (USA), 7 Mar.
"Some fundamental questions of space-charge
physics"
3) S. Adam, Paul Scherrer Institut (Switzerland) , 21
Apr.
"Routine operation of the PSI Accelerator Facility at a beam power of 0.9 megawatt"4) G. Melin, CEA-Grenoble (France) , 18 May"Evolution of electron cyclotron resonance ion
source (ECRIS) of highly charged ions from classical to superconducting sources"5) G. Shirkov, JINR (Russia), 4 Sept.
"Physical and numerical basement of ECR
plasma simulation with particle-in cell model"
6) T. Hori , Sumitomo Heavy Industries Ltd.
(Tanashi) , 28 Sept.
"Present status and design concept of compact
SR source AURORA2S"
7) A. Dael, CEA-Saclay (France), 5 Dec.
"BO construction and Saclay activities"
8) S. M. Lund, LLNL (USA) , 11 Dec.
"Axial bunch compression ion rings through fastbunch"
Radioisotope Technology Div.

15) J. Eichler, Hahn-Meitner-Institut Berlin (Germany) , 10 Nov.
"Ion-atom collisions at relativistic velocities"

1) S. Kodama, Nagasaki University (Nagasaki), 11
Oct.
"Mechanisms of radiation-induced genetic instability"16) C. T. Whelan, University of Cambridge (UK), 24Nov.
"( e, 2e) and related processes"

2) K. Ohta, RIKEN (Wako), 11 Oct.
"The role of Mre-ll in DNA recombination andtelomere main tenance"

403

RIKEN BNL Research Center
1) J. Smith, SUNY, Stony Brook (USA) , 5 Jan.
"Variable flavor number schemes for heavy quark
electroprod uction"2) J. Raufeisen, Institut fUr Theoretische Physik,
University Heidelberg (Germany), 14 Jan.
"Light-cone approach to nuclear shadowing in
DIS and to the Drell-Yan process"3) E. Souza Fraga, BNL (USA), 20 Jan.
"The role of fermions and dynamical viscosity innucleating bubbles"4) S. Raha, BNL (USA)jBose Institute (Calcutta),
21 Jan.
"Some aspects of strangeness in astrophysics andcosmic rays"
5) Y. Kuramashi, Washington University (USA) , 26Jan.
"N ucleon decay matrix elements from lattice
QCD"6) S. White, BNL (USA) , 27 Jan.
"A program of measurements with an internal
target at RHIC"
7) M. Baker, BNL (USA) , 1 Feb.
"Transversity"
8) F. Maltoni, University of Illinois at UrbanaChampaign (USA) , 2 Feb.
"Quarkonium phenomenology: Status and directions"
9) F. Gelis, BNL (USA) , 3 Feb.
"Photon and dilepton production by a quarkgluon plasma"10) R. Rapp, SUNY, Stony Brook (USA) , 4 Feb.
"Thermal dileptons: Chiral restoration and QGP
radiation"11) M. Alford, MIT (USA) , 9 Feb.
"Scalar mesons and pion scattering on the lattice"12) J. Ollitrault , Saclay (France) , 11 Feb.
"Effects of HBT correlations and momentum conservation on flow at SPS"
13) A. Henneman , Vrije University (The Netherlands) , 15 Feb.
"Soffer-like bounds on distribution functions withtransverse momentum"40414) M. Neubert, Cornell University (USA) , 16 Feb.
"Theory of hadronic B decays"15) J. Schaffner-Bielich, RIKEN BNL Rresearch Center (USA), 17 Feb.
"Weak decay of strange dibaryons"16) R. Malfliet, ECT* (Italy), 18 Feb.
"Non-classical behaviour in non-equilibrium
quantum systems"17) S. White, BNL (USA) , 22 Feb.
" A~ measurement at RHIC"
18) J. Verbaarshot , SUNY, Stony Brook (USA), 23
Feb.
"Exact results for QCD dirac spectra at zero andfinite baryon density"19) A. Peshier, BNL (USA) , 24 Feb.
"Thermodynamics of the QGP at finite chemical
potential"
20) S. Bass, lV1ichigan State University (USA) , 25
Feb.
"Dynamics of hot bulk QCD matter: From QGP
to hadronic freeze-out"21) W . Guryn, BNL (USA), 29 Feb.
"Summary of the J et target workshop"
22) D. Bodeker, Niels Bohr Institute (Germany), 1
Mar.
"The dynamics of magnetic scale gluons"23)

S. Jeon, Ernest Orlando LBNL (USA) , 3 Mar.
"Charged multiplicity ratio fluctuations as a QGP
signal"24) G. Weiglein, Conseil Europeen pour la Recherche
Nucleaire (Switzerland), 8 Mar.
"Higgs and electroweak precision physics atpresent and future colliders"25) A. Hebecker, University of Heidelberg (Germany), 10 Mar.
"Diffractive parton distributions"
26) D. Wackeroth, University of Rochester (USA) , 15Mar.
"Four-fermion production at present and future e+e- colliders: Precise predictions fromRACOONWW"
27) D. Rischke, BNL (USA) jRIKEN BNL ResearchCenter (USA) , 17 Mar.
"Color superconductivity in cold dense quark

matter"28) T. Csorgo, Columbia University (USA)/KFKI(Hungary), 23 Mar.
"Back-to-back correlations of bosons andfermions at RHIC"
29) G. J. Lolos, University of Regina (Canada), 24Mar.
"Mass and helicity modifications in low energy p
photoprod uction""Leptogenesis from preheating in hybrid inflation"41) N. Saito, RIKEN (Wako)/RIKEN BNL ResearchCenter (USA) , 2 May"Report from DIS2000"42) E. Simmons, Boston University (USA), 3 May"Exploring new electroweak interactions for thethird generation"30) F . Meissner, DESY-Zeuthen (Germany), 27 Mar.
"Spin asymmetry in vector meson production in
HERMES"

43) T . D. Lee , Columbia University (USA)/RIKEN
BNL Research Center (USA), 4 May"A new method to derive n-dimensional quantum
wave functions"31) X. Wang, Ernest Orlando LBNL (USA) , 30 Mar.
"Multiple scattering and parton energy loss in eA
collisions"44) A. Dumitru, Columbia University (USA), 5 May"Coupling of soft and hard modes of chiral condensates in real time lattice simulations"32) D. Riska, University of Helsinki (Finland), 31
Mar.
"The strange form factors of the proton: SAMPLE, HAPPEX, and the anapole moment"45) M. Perdekamp, RIKEN BNL Research Center(USA) , 9 May"More report from DIS2000"

33) R. Jakob, Wuppertal University (Germany), 4
Apr.
"Interference fragmentation funct ions"34) R. Lebed , Jefferson Laboratory (USA) , 11 Apr.
"Masses of orbitally excited baryons in large Nc
QCD"35) M. Diehl, Stanford Linear Accelerator Center(USA) , 11 Apr.
"Deeply-virtual Compton scattering"36) T. Schaefer, RIKEN BNL Research Center(USA)/SUNY, Stony Brook (USA) , 13 Apr.
"Gluino condensation and instantons"37) M. Diehl, Stanford Linear Accelerator Center(USA) , 14 Apr.
"Learning more about the proton structure: Parton distributions and beyond"38) D. Son, Columbia University (USA)/RIKEN
BNL Research Center (USA) , 20 Apr.
"Avoiding the sign problem: QCD at finite
isospin density"39) A. Muronga, University of Minnesota (USA) , 21
Apr.
"Dissipative fluid dynamics for relativistic nuclear
collisions"40) J. Garcia-Bellido, Imperial College (UK), 26 Apr.

46) E. Shuryak, SUNY, Stony Brook (USA)/RIKEN
BNL Rresearch Center (USA) , 18 May"Instanton-induced effects and high energy processes"47) M. Bai, BNL (USA) , 23 May"Improving polarization at AGS"48) L. Everett , University of Michigan (USA) , 24 May"CP violat ion and flavor in type I superstringmodels"49) R. Kaiser, DESY-Zeuthen (Germany) , 30 May
at"Polarized
electron-nucleon
scattering
TESLA"
50) R. Kaiser , DESY-Zeuthen (Germany) , 30 May"The HERMES RICH detector"51) C. Aragao de Carvalho, Universidade Federal do
Rio de Janeiro (Brazil) , 31 May"Phase transitions in field theories"52) G. Carter, SUNY, Stony Brook (USA), 2 June
"Neutrino propagation in color superconducting
quark matter and protoneutron stars"53) A. Belitsky, SUNY, Stony Brook (USA) , 6 June
"Extraction of skewed parton distributions"54) L. Lellouch, CPT, CNRS Luminy (France), 7
June"Non-leptonic weak decays from euclidean corre-405

lation functions"age rings"

55) A. Yelkhovsky, Budker Institute (Russia), 14
June"Ground state of the helium atom"70) M. Nowak, Jagellonian University (Poland) , 22
Sept.
"piO ---+ I I in dense QCD"

56) K. Melnikov, Stanford Linear Accelerator Center(USA), 21 June"Three loop renormalization of QED and QCD"

71) M. Stratmann, Regensburg University (Germany) , 26 Sept.
"Polarized heavy flavor production in NLO QCD"

57) Z. Bern, UCLA (USA), 28 June
"NNLO QCD"

72) M. Polyakov, St. Petersburg, INP (Russia)/Ruhr
University (Germany), 26 Sept.
"Stratmann and ubar- dbaqr asymmetry in the(polarized) nucleon sea"

58) Z. Duan, Yale University (USA), 29 June
"Low energy theory for two flavors at high density
QCD"59) F. Sannino, Yale University (USA) , 30 June
"Entropy and phases of chiral gauge theories"60) S. Pate, New Mexico State University (USA), 6
July"Polarized lambda production"61) R. Yoshida, Argonne National Laboratory (USA) ,11 July"Proton structure measurements from HERA"
62) A. Arbuzov, INFN (Italy), 12 July
"Radiative corrections to e+e- scattering"63) S. Bueltmann, University of Virginia (USA) , 18
July
"Recent results from E155"
64) M. H. G. Tytgat , Conseil Europeen pour la
Recherche Nucleaire (Switzerland) , 26 July
"Surfing on non-commutative waves"65) 1. Ya. Glozman, University of Graz (Austria), 11
Aug.
"Baryon structure in the low-energy regime of
QCD"66) M. Stratmann, Regensburg University (Germany) , 12 Sept.
"Current issues in polarized PDF analyses"
67) S. Nussinov , Tel Aviv University (Israel), 13 Sept .
"The rise and fall of the crossection"68) M. Nowak, Cracow, 14 Sept.
"Disorder in QCD and diffusion of the lightquarks in t "69) Y. Derbenev, DESY (Germany) , 21 Sept.
"Stern gerlach polarization of antiprotons in stor-

40673) K. Sasaki, Yokohama National University (Yokohama) , 27 Sept .
"Parton distributions in the polarized virtualphoton target"74) G. Sterman, SUNY, Stony Brook (USA) /BNL(USA) , 11 Oct.
"Combining threshold and transverse momentum
resummations"75) M.-A . Halasz , University of Pennsylvania (USA) ,20 Oct .
"Random matrices and the sign problem in QCD
at finite mu"76) I. Zahed, SUNY, Stony Brook (USA) , 27 Oct.
"Non-perturbative approach to high energy scattering in QCD"
77) M. Muehlleitner, DESY (Germany), 1 Nov .
"Higgs pair production at high-energy colliders"78) T. Fugleberg, BNL (USA) , 2 Nov.
"A signal for induced theta vacua"79) E. Gubankova, North Carolina State University(USA) , 3 Nov .
"Solving QCD Hamiltonian for bound states"80) I. Balitsky, Jefferson Laboratory (USA)/Old
Dominion University (USA), 8 Nov.
"Renormalons as dilatation modes in the functional space"81) F. Laue, M. Calderon, A. Poskanzer, 9 Nov.
"STAR data from RHIC: HBT, h-spectra, flow"82) S. Soff, BNL (USA), 14 Nov.
"Strangeness, collective flow and correlations asprobes of excited nuclear matter"83) D . Zeppenfeld, University of Wisconsin (USA) , 15Nov.
"Prospects for intermediate mass higgs studies atthe LHC"84) A. Basilevsky, S. Mioduszewski, J. Burward-Hoy,
RIKEN BNL Research Center (USA), 16 Nov.
"PHENIX: Transverse energy; Neutral pion production; Charged hadron pt"
85) J. Raufeisen, Ernest Orlando LBNL (USA), 17
Nov.
"QCD coherence effects in high energy reactions
with nuclei"86) D. Boer, RIKEN BNL Research Center (USA),
28 Nov.
"Towards a global transversity analysis"

nite temperature"92) B. Fox, University of Colorado (USA), 12 Dec.
"Deeply virtual Compton scattering"93) H. Cheng, Academia Sinica (Taiwan)jBNL(USA) , 13 Dec.
"Some aspects of hadronic charmless B decays"94) D. Kharzeev, BNL (USA), 14 Dec.
"What do we learn from the first data on hadronproduction at RHIC?"
95) M. Okawa, KEK (Tsukuba) , 20 Dec.
"Toward the 2 + 1 flavor QCD simulation withexact fermion algorithm"
Image Information Div.

87) Y. Aoki, RIKEN BNL Research Center (USA),
30 Nov.
"Chiral properties of domain-wall quarks inquenched QCD"
88) J. Bowers, MIT (USA), 1 Dec.
"Crystalline color superconductivity"89) T. Tait, Argonne National Laboratory (USA), 6
Dec.
"Flavor and supersymmetry breaking from asmall extra dimension"90) A. Zhitnitsky, British(Canada) , 7 Dec.
"QCD domain walls"

Columbia University91) J. A. Wirstam, BNL (USA), 7 Dec.
"Effective actions and world-line methods at fi-

1) Y. Otake, RIKEN (Harima), 7 June
"The possibility of the detection between the coherency and decoherence"2) J. Kawarabayashi, Nagoya University (Nagoya),
29 June"Single electron transistor for radiation measurement application"3) F. Klose, Spallation Neutron Source (USA) , 10Nov.
"Optical components for reflectometer at SNS(Spallation Neutron Source)"4) D. Fukuda, University of Tokyo (Tokyo), 13 Nov.
"Development of radiation detectors with superconductive materials"407

XII. LIST OF PERSONNELRIKEN ACCELERATOR RESEARCH FACILITYTANIHATA Isao ~ ~ffi ~ ~ (Facility Director)
YANO Yasushige 9C if 17: 1i (Vice Facility Director)
Linac Division

FU JIMAKI Masaki Hi ~ lE tM
KASE Masayuki DO ~ ~
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IKEZAWA Eiji 7fu rR "!1i:
KOHARA Shigeo IJ'\ J]{ 1i ~Ring Cyclotron Division=

FUJITA Jiro Hi 83~~
INABE Naohito tIB ill. raJ A
KAMIGAITO Osamu ..t!~)1.{I~­KOHARA Shigeo IJ'\ J]{ 1i ~NAGASE Makoto -R 11~
OGIWARA Kiyoshi ~ J]{
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Experimental Support Division

ICHIHARA Takashi rtf J]{
KAN AI Yasuyuki 31£:# 1* Z
MORITA Kosuke ~i~ 1r
YATAGAI Fumio ~m~Jt~*

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IKEGAMI Kumio 7tt!...tn=~
KAG EYAMA Tadashi ~ LlJ
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KASE Masayuki DO ~ ~*1
KUBO Toshiyuki j... 1* fW. ¥NAKAGAWA Takahide 9=' )11 1f. ~OKUNO Hiroki ~ if It. tifz

KAMBARA Tadashi 1$ J]{lE *1
MATSUZAKI Teiichiro t~~t~rtf~~
WATANABE Yasushi iJi jI
EftRadioisotope Facilities Division

KOBAYASHI Yoshio

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IJ'\

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YATAGAI Fumio~EB~Jt~ *1

Radiation Protection Group
FUJITA Shin Hi~}f * 1
OGIWARA Kiyoshi ~)Jj(
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ITO Sachiko

Administration Division
MANABE Tadashi ~ ~NUMATA Shigeo ii3 m

NAKAMURA Toshikomr.!! *2a~Steering Committee
ASAHI Koichiro M fjj: - ~~HANAOKA Fumio 1E /trrJ Jt ift
KAMBARA Tadashi 1$ J]{
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KATAYAMA Takeshi h LlJ
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MANABE Tadashi ~ ffUJr.!!
NAG AMINE Kanetada 71<. ~ ~ ,[I,TANIHATA Isao ~ ~ffi ~ ~YAN 0 Yasushige
if 17: 1i
YOSHIDA Shigeo E rn
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* 1 Group Leader , *2 Manager,408

a*3 Chairperson

1fr Hi tif +9=' ft t L +GOTO Akira 1& Hi~
ICHIHARA Takashi rtf J]{
KASE Masayuki DO ~ ~ Z
KATSUMATA Koichi ~ X tt MATSUZAKI Teiichiro tj}~tJrmf!~
SAWA Hiroshi
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YAMAZAKI Yasunori LlJ i1J~ ~ m*3
YATAGAI Fumio ~mJ!Jt~*i'*******************************************
Members (included Special Postdoctral Researcher,
RIKEN Fellow, and Contract Researcher)*******************************************
Cosmic Radiation Laboratory
Members
KATO Hiroshi 110 jj'i
tf
YOSHIDA Atsumasa E B3 _ iE

MIYASAKA Hiromasa

g ~ i~ iE

Visiting Members
GOKA Tateo Ii~:;k: (NASDA)
KOSHIISHI Hideki ~ E 3i; tt:!" (NASDA)
MATSUMOTO Haruhisa tt::$: 8Ff -)... (NASDA)*

Radiation Laboratory
Head
TANIHATA Isao ~m~ :;k:Members
ICHIHARA Takashi rtf JJj{¥
YOSHIDA Atsushi
B3~i
SAITO Naohito ~ jj'i ~ A
WATANABE Yutaka iJi it
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HAYASHI Naoki~ tt:!"YASUI Yoshiaki 1;:#-,& ~

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WATANABE Yasushi iJi ii
KISHIDA Takashi
B3~~
TAKETANI Atsushi it ~_MURATA Jiro tt B3
f1~
NAITO Kenichi I*J jj'i ~ ISHII Noriyoshi E:#-:@ {I~**Visiting Members
AKIBA Yasuyuki fx ~ E1t Z (KEK)
ANDO Yoshiaki 1; jj'i ~ ~ (ColI. Sci. , Rikkyo Univ.)AOI Nori W:#~
(Dept. Phys. , Grad. Sch. Sci., Univ. Tokyo)
AS AI Masato ¥3t:#A (J AERI)AS AMI Hiroyasu ¥3t iHi: ~L 1* (KEK)
AWAYA Yoko ~ ~ ~.:r (Musashino Art Univ.)
BAUMANN Thomas(Natl. Superconducting Cycl. Lab., Michigan State Univ., USA)
BECK F. A.
(CRN, France)
BENTZ Wolfgang(Dept. Phys. , Grad. Sch. Sci., Univ. Tokyo)
BROGLIA R.
(Univ. di Milano, Italy)
BROOKS Melynda (LANL, USA)
BURWARD-HOY Muriel Jane
(Dept. Phys., SUNY, Stony Brook, USA)CASTEN Rick(Phys. Dept., BNL, USA)CHUJO Tatsuya ~ {I* Jl tIL (Phys. Dept. , BNL, USA)COLO Gianluca (Univ. di Milano, Italy)
CRIST Norman(Columbia Univ., USA)DOOI Makoto 1it:#•(Inst. Phys. , Univ. Tsukuba)
EN'YO Hideto }[ --9- ~ A (Fac. Sci., Kyoto Univ.)
FLOCARD Hubert(Div. Phys. Theor. lPN, Inst. Phys. Nucl. , France)
~f ~
(KEK)
FUCHI Yoshihide i*~
FUJII Hirotsugu jj'i:#- 1.l(Grad. Sch. Arts Sci., Univ. Tokyo)
FUJIKAWA Kazuo jj'i)ll fO ~ (Fac. Sci., Univ. Tokyo)
FUKUDA Mitsunori 1~ B3 Jt jllJ[ (Grad. Sch. Sci. , Osaka Univ.)
FUKUDA Naoki 1~ B3 ~ tt:!" (Dept. Phys., Grad. Sch. Sci., Univ. Tokyo)
FUKUDA Tomokazu 1~ B3 ~ fo (KEK)
FURUTAKA Kazuyoshi ~ ~ fo t~ (JAERI)GELBERG Adrian(Koln Univ., Germany)
HAMAMOTO Ikuko i~::$: W.:r (Univ. Lund, Sweden)
HATSUDA Tetsuo f}] B3 ~ ~ (Fac. Sci. , Kyoto Univ.)*Jf (Dept. Phys., Grad. Sch. Sci. , Univ. Tokyo)
HAYASHIGAKI Arata

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409

HORIUCHI Hisashi Wi I*J
m! (Fac. Integr. Human Studies, Dept. Fundamental Sci., Kyoto Univ.)
HOTTA Tomohiro Wi E8 ~ 7$ (Grad. Sch. Arts Sci., Univ. Tokyo)
ICHIMURA Munetaket;J m: (Grad. Sch. Arts Sci., Univ. Tokyo)
IDEGUCHI Eiji #-f-D5R¥S (Dept. Chern. Washington Univ. , USA)
IEKI Kazuo *:9iX; ~D(ColI. Sci., Rikkyo Univ.)
IMAI Kenichi ~ # ~ (Fac. Sci. , Kyoto Univ.)
J1[ -T (Lab. Phys., ColI. Sci. Technol. , Nihon Univ.)
IMOTO Michiko #ISHII Tetsuro E # :tg~}j (J AERI)IWASAKI Hironori :5 Ill~ ~L. $(Dept. Phys., Grad. Sch. Sci., Univ. Tokyo)
IZUMI Hideaki /:H 7k Jij S)j (Grad. Sch. Sci., Osaka Univ.)
JIN Genming 1fJf
fi S)j (Inst. Modern Phys., Chinese Acad. Sci., China)
KAKI Kaori a m ~ (Fac. Sci., Shizuoka Univ.)
KAMAE Tsuneyoshi ~ iI ~ ~f (Fac. Sci. , Univ. Tokyo)
KASAGI Jirota !2:*¥S~~* (Lab. Nucl. Sci., Tohoku Univ.)
KATO Seigo DO ni ijf::g. (Fac. Ed., Yamagata Univ.)
KIM Jong Chan i:~l j{(Dept. Phys., Seoul Natl. Univ., Korea)
KISTENEV Edouard(Phys. Dept. , BNL, USA)KITAO Kensuke %~~~1iJJ (Data Eng. Inc.)KODAIRA Jirou IJ~ if ¥S ~~ (Fac. Sci. , Hiroshima Univ.)
KOHAMA Akihisa IJ~ it 7$ ~ (Fac. Sci., Univ. Tokyo)
KOIKE Yuji IJ~ n!!
I5J (Fac. Sci. , Niigata Univ.)
KUMANO Shunzo ~.~ it 1~ = (Fac. Sci. Eng., Saga Univ.)
KUNIHIRO Teiji ~ ~L. 'I~(YITP, Kyoto Univ.)~(Fac. Ed. , Chiba Univ.)
KUSAKARI Hideshige 1i-){1j
LIU Guanhua ~U
7tt(Inst. Modern Phys., Chinese Acad. Sci., China)
LIU Zhong(Inst. Modern Phys. , Chinese Acad. Sci. , China)
LOMON Earle(Massachusetts Inst. Technol. , USA)
MAO Yajun(Phys. Dept., BNL, USA)
MATSUDA Satoshi tl E8~(Fac. Integr. Human Studies, Dept. Fundamental Sci., Kyoto Univ.)
MATSUI Tetsuo t~ # ~ §15 (YITP, Kyoto Univ.)
MATSUYANAGI Kenichi tl tgp ~Jf (Fac. Sci., Kyoto Univ.)
MENGONI Alberto(Phys. Div., ENEA, Italy)~~(Inst. Phys., Univ. Tsukuba)
MIAKE Yasuo =: I3Ji
MIN Byung-Joo 00~:f*(Korea Atomic Energy Res. Inst., Korea)
MITARAI Shiro 1wP-f-j7t;t:~~ (Fac. Sci. , Kyushu Univ.)
MIYAMA Masanori iW. LiJ lE if2. (Fac. Sci. , Tokyo Metrop. Univ.)
MIYATAKE Hiroari '8 m:ill (KEK)
MOLLER Peter(LANL, USA)MORII Toshiyuki ~ # 1~ 1-1 (Fac. Human Dev., Kobe Univ.)
MORIKAWA Tsuneyasu ~ JII 'I:l~: 17: (Fac. Sci. , Kyushu Univ.)
MORINOBU Shunpei ~ 1~ 1~ if (Fac. Sci., Kyushu q niv.)
MOTOBAYASHI Toru~
(ColI. Sci. , Rikkyo Univ.)
MOTTELSON Ben R.
(Nordita; Nordisk Inst. Teoretisk Fysik, Denmark)
MUELLER Ludwig(Phys. Dept. , Univ. di Padoba, Italy)
MURAKAMI Takeshi t;J 1:.
~(Natl. Inst. Radiol. Sci.)
MURAKAMI Hiroyuki t;J 1:. i~ Z (ColI. Sci., Rikkyo Univ.)
NAGAI Yasuki 71<. # ~ tM (RCNP, Osaka Univ.)
NAGAMIYA Shoji 71<. '8 lE is (KEK)
NAKAJIMA Mitsuo r:p!ZJ 7C(Grad. Sch. Nagatsuta, Tokyo Inst. Technol.)
NAKAMURA Shogo r:p t;J lE 1fr (Fac. Ed., Yokohama Natl. Univ.)
NAKAMURA Takashi r:p f;J ~i I5J (Tokyo Inst. Technol.)
NAKAMURA Masanobu r:p f;J lE 1~ (Fac. Sci., Kyoto Univ.)
NAKAYAMA Shintaro r:pLiJ1~*~~ (Fuc. Integr. Arts Sci., Univ. Tokushima)
NEMOTO Yukio fi *"$(RCNP, Osaka Univ.)
NIIZEKI Takashi *Jf 1*1~i(Tokyo Kasei Univ.)
NISHIMURA Jun W tt?¥ (Cen. Integrated Res. Sci. Eng., Nagoya Univ.)
NORO Tetsuo it g ~(RCNP, Osaka Univ.)

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ODAHARA Atsuko 1j-,83)Jj(W-f- (Nishinippon lnst. Technol.)
OGAWA Masao IJ\)l1 ~ ~ (Tokyo Inst. Technol.)OHSHIMA Kazuto~~
A (Gunma Natl. ColI. Technol.)
OKAMURA Hiroyuki ItliJ 11" ~t. Z (Fac. Sci., Saitama Univ.)
OOISHI Ryutaro *Eil:k~~ (lnst. Phys., Univ. Tsukuba)
ORIHARA Hikonojyo ~)Jj(~zZ1S (Cycl. Radioisot. Cen. , Tohoku Univ.)
OSHIMA Masumi
1ft/;; ~ ii:(JAERI)j~ 1f. ~5(Fac. Sci., Univ. Tokyo)
OTSUKA Takaharu
PAN Qiangyan it~m:fi(lnst. Modern Phys., Chinese Acad. Sci.)
PENIONZHKEVICH louri(Flerov Lab. Nucl. React. , Joint Inst. Nucl. Res., Russia)
PIERROUTSAKOU Dimitra(Sez. Napoli (INFN), Italy)
REN Zhongzhou if:
9=J 11+1 (Nanjing Univ. , China)(Cen. Math. Sci., Univ. Aizu)
SAGAWA Hiroyuki 1~]II ~L. ¥SAKAGUCHI Harutaka :t& D ~5~.i (Fac. Sci., Kyoto Univ.)
SAKURAGI Hiroyuki tM~t. Z(Fac. Sci., Osaka City Univ.)
SAKURAI Hiroyoshi tM it tf" (Dept. Phys. Grad. Sch. Sci., Univ. Tokyo)
SASAKI Shoichi 1!4:;if:M}- (Dept. Phys. Grad. Sch. Sci., Univ. Tokyo)
815 (KEK)
SATO Hikaru 1tc Iii
SATO Hiroki 1tc Ji tf *2. (Fac. Sci. , Kyoto Univ.)
SAWADA Shinya i' 83 ~ ill (KEK)
SCHAEFER Markus(Phys. lnst., Univ. Goettingen, Germany)
SCHMIDT-OTT Wolf-Dieter(Phys. lnst. , Univ. Goettingen, Germany)
SEDERWALL Bo(Royal lnst. Technol., Sweden)
SHIBATA Toshiaki ~ 83 tlJ ~ (Tokyo lnst. Technol.)
SHIGAKI Kenta iE':!~ Jf:k (KEK)
SHIMIZU Hajime 1ff 71<.
~
(Fac. Ed., Yamagata Univ.)
SHIMIZU Yoshifumi ¥ff 71<. .& X (Fac. Sci., Kyushu Univ.)lE (Grad. Sch. Sci. , Osaka Univ.)
SHIMODA Tadashi r 83
SIGNORINI Cosimo(Phys. Dept. , Univ. di Padoba, Italy)
STROE Lucian(Phys. Dept., Univ. di Padoba, Italy)
SUGAWARA Masahiko 1f JJi( ~ ~ (Chiba Inst. Technol.)
SUGITATE Toru ;f~ JL
11& (Fac. Sci., Fac. Sci. Hiroshima Univ.)
SUZUKI Yasuyuki ~~:;if: Jt Z (Fac. Sci., Niigata Univ.)
SUZUKI Katsuhiko ~~:;if: R ~ (Dept. Phys., Grad. Sch. Sci., Univ. Tokyo)
SUZUKI Toshio ~~:;if: fW. ~ (Fac. Eng., Fukui Univ.)
TAJIMA Yasuhisa 83 1ft/;; i~:A (Cycl. Radioisot. Cen. , Tohoku Univ.)
TAKADA Eiichi ~ 83 %: (Natl. Inst. Radiol. Sci.)(Inst. Space Astro. Sci.)
TAKAHASHI Tadayuki ~ ifi }~, ¥TAKEMOTO Hiroki ¥r
7i ~l (JAERI)
TAKIGAWA Noboru ?~]II.Jt (Grad. Sch. Sci., Tohoku Univ.)
TAKIZAWA Makoto iln~(Showa ColI. Pharm. Sci.)
TAMIl Atsushi ~ it(Fac. Sci., Univ. Tokyo)
TANAKA Masahiko 83 $ ~ ~ (KEK)
TANOKURA Atsushi 83fl'~ ~5c (Fac. Sci. Technol. , Sophia Univ.)
TENDOW Yoshihiko ~ ~ 7i ~TERAKAWA Atsuki ~ JII • lit (Cycl. Radioisot. Cen., Tohoku U niv.)TORII Hisayuki ,~it:A iT (Fac. Sci., Kyoto Univ.)
TOYAMA Takeshi ji- ill~(KEK)
TOYOKAWA Hidenori ':')11 ~ ~J11 (JASRI)
UEMATSU Tsuneo f~ 1~ 'Ili ~ (Fac. Integr. Human Studies, Dept. Fundamental Sci., Kyoto Univ.)
UENO Hideki .1. fl' ~ lit (Lab. Nucl. Studies, Fac. Sci. , Osaka Univ.)
UNO Masahiro
fl' lE 7i (Min. Ed. Sci. Sports Culture)
WAKAMATSU Masashi ~ ti} lE iE': (Lab. Nucl. Studies, Fac. Sci., Osaka Univ.)
WAKASA Tomotsugu ~ ~X ~ ifflm (RCNP, Osaka Univ.)
WHITE Sebastian(Phys. Dept., BNL, USA)XU Shuwei 1~
lit ~ (Inst. Modern Phys., Chinese Acad. Sci., China)
YAMANISHI Teruya ill 1ZB ~l ill (Fac. Eng., Fukui Univ. Technol.)

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411

YAMASHITA Yoshiki LlJ T 7i 111" (Hirosaki Univ.)(Tokyo Women's Chr. Univ.)
YAZAKI Koichi "*- ~~ {fk YOKKAICHI Satoshi [zg 8 m 'It (Fac. Sci., Kyoto Univ.)
YOSHIMURA Koji E ft
15] (Int. Cen. Element. Part. Phys., Univ. Tokyo)
YOSHINAGA Naotaka E 1K ri16 4(Fac. Sci., Saitama Univ.)YOSOI Masaru w.~# 11 (Fac. Sci., Kyoto Univ.)
ZHANG Yu-Hu ~.:E dE. (lnst. Modern Phys., Chinese Acad. Sci., China)
Ij,(lnst. Modern Phys., Chinese Acad. Sci., China)
ZHOU Xiaohong mJ
ZHU Lihua(China Inst. Atom. Energy, China)

i*

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Trainees
BABA Hidetada ,~j:~I~'(ColI. Sci., Rikkyo Univ.)
DEMICHI Kimihiko I:IJ JEt 1= ~ (ColI. Sci., Rikkyo Univ.)
FUKUCHI Tomonori tm it!? ~D ~Ij (Fac. Sci., Kyushu Univ.)
FUSAWA Hirofumi tJ i'tf X (Fac. Sci., Niigata Univ.)
FUTAKAMI UdaiJ:.
r*J (ColI. Sci., Rikkyo Univ.)
GOMI Tomoko 11.
~)j(ColI. Sci., Rikkyo Univ.)
HASEGAWA Hirokazu *~Jlli*- (ColI. Sci., Rikkyo Univ.)
HATANO Michio r~tp.ffJEt:}( (Dept. Phys., Grad. Sch. Sci., Univ. Tokyo)
HIGURASHI Yoshihide 8 ~ ~ ~ (ColI. Sci., Rikkyo Univ.)
HIRAI Masanori 5:f #- IE *-2. (Fac. Sci. Eng., Saga Univ.)
IKEDA Hiroshi rt!! B3
E8 (Tokyo lnst. Technol.)
INOUE Masaki #- J:. IE 111" (Fac. Sci., Kyushu Univ.)
ISHIDA Tomoyuki JEi E8 ~ Z(Dept. Phys., Grad. Sch. Sci., Univ. Tokyo)
KANEKO Emi ~2: ~ (ColI. Sci., Rikkyo Univ.)
KANNO Syouko ;g ff t.f(ColI. Sci., Rikkyo Univ.)
KASHIYAMA Osamu ~ ill
11~(Fac. Sci., Kyushu Univ.)
KATO Hiromitsu TIO Ji tft 7E (Dept . Phys., Grad. Sch. Sci., Univ. Tokyo)
KAWASAKI Hiroaki iPT ~~ i$ ijf (ColI. Sci., Rikkyo Univ.).KINUGAWA Hiroto tf.. JlI 1ft A (ColI. Sci., Rikkyo Univ.)
KISHI Chieko
T 2:(ColI. Sci., Rikkyo Univ.)
KIYOMICHI Akio 1~ ~ EY3 ~ (lnst. Phys., Univ. Tsukuba)
KOBAYAKAWA Akira Ij'!f!.JII ~ (Dept. Phys., Grad. Sch. Sci., Univ. Tokyo)
KUNIBU Makoto ~ 5t
WiX;
(ColI. Sci., Rikkyo Univ.)
KUROKAWA Minako ~]lI=::~r (Tokyo Inst. Technol.)
MAEDA Yukie 1W B3 $.£ (Dept. Phys. , Grad. Sch. Sci., Univ. Tokyo)
MATSUURA Taeko f~ iffl ~tJ;
(Dept. Phys., Grad. Sch. Sci., Univ. Tokyo)
MATSUYAMA Yuuichi tl UJ tft (ColI. Sci., Rikkyo Univ.)
MINEMURA Toshiyuki
ft 1~ 1T (ColI. Sci., Rikkyo Univ.)
MIURA Motooki :::: iffl 5C ~f (Tokyo lnst. Technol.)
MIYAKAWA Takahiko g]ll" ~ (Fac. Sci., Tokyo Metrop. Univ.)
MORINAGA Mitsutoshi ~ 1K 7t 5f1j (Dept. Phys. , Grad. Sch. Sci., Univ. Tokyo)
MOTOMURA Shinji
ft 1§" ¥is (Fac. Sci., Kyushu Univ.)
MUTO Ryotaro m:Ji ;t*f1~ (Fac. Sci., Kyoto U niv.)
NAKAJIMA Noriaki ~ liJJ ~ BB (RCNP, Osaka Univ.)
NAKAMURA Hideki . ~ ft 1§ ;.ftt (Dept. Phys., Grad. Sch. Sci., Univ. Tokyo)
NAKANO Jo q:r ff
nl (Dept. Phys., Grad. Sch. Sci., Univ. Tokyo)
NAKANO Eiji 1rp ff
15] (Fac. Sci., Tokyo Metrop. Univ.)
NARUSHIMA Koichi nX: 1Il~ Jj] (ColI. Sci., Rikkyo Univ.)
OHKUMA Kazumasa
1f~ - IE
(Fac. Human Dev., Kobe Univ.)
ONO Masaya Ij, If :fft ill (Inst. Phys., Univ. Tsukuba)
SAHA Pranab(KEK)
SAITO Koji ~ Ri15] (Fac. Sci., Kyushu Univ.)
SAITO Takaaki ~ Jii 4 ~ (Dept. Phys., Grad. Sch. Sci., Univ. Tokyo)
SAITOU Akito ~ Jii Sf] ~ (ColI. Sci., Rikkyo Univ.)
SAKODA Seitaro :i§B3IDOC*f1~ (Dept. Phys., Grad. Sch. Sci., Univ. Tokyo)
SATO Kyosuke it Jii
t{] (ColI. Sci., Rikkyo Univ.)

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SHIMBO Ken fJf 1~~(Dept. Phys., Grad. Sch. Sci. , Univ. Tokyo)
SUDOH Kazutaka ~J{ ~ ;fo ijX (Fac. Human Dev. , Kobe Univ.)
SUETSUGU Kentaro **1l*~~ (Tokyo Inst. Technol.)(Tokyo Inst. Technol.)
SUGIMOTO Takashi if~
SUZUKI Miwako ~iJ*~;fOr (Inst. Phys. , Univ. Tsukuba)
TAKESHITA Eri tT T
JJ. (ColI. Sci. , Rikkyo Univ.)
TOJO Junji *:tJ&; }Ir~ is (Fac. Sci. , Kyoto Univ.)
11 (ColI. Sci., Rikkyo Univ.)
TOZAWA Yuichi iff
TSURUOKA Hiroshi t.~ IiYiJ± (Inst. Phys., Univ. Tsukuba)
UCHIGASHIMA Nobuyuki P'17 ~If%Z (Dept. Phys. , Grad. Sch. Sci. , Univ. Tokyo)
tt (ColI. Sci. , Rikkyo Univ.)
YAMAMOTO Minoru LlJ(Fac. Sci. , Kyushu Univ.)
YANAKA Shuichi B3 q:t mJ -

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TANIHATA Isao ~ 1m ~ :jc
Members
FUKUYAMA Yoshimitsu fi LlJ 1$ 7t
KORSHENINNIKOV Alexei A.
KUSAKA Kensuke B T llf;b
MOCHIZUKI Yuko ~ Ji 1~
NAKATSUKASA Takashi Ii=' ~1t
NISHIMURA Shunji "@ ift ~ONISHI Takashi *"@SUDA Toshimi ~J{ ffi flj ~WAKUI Takashi i~ itit
YAMAZAKI Toshimitsu LlJ i1J~ fit 7t

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MATSUO Yukari t~~EE~flJ
MORIMOTO Koji ~¥ P]
NISHI Yuji "@~OZAWA Akira IJ'\ tR~~
ONHISHI Tetsuya"@ :rg- t!1
SUMIYOSHI Kohsuke 11 fi 7t 1r
YAMAGUCHI Takayuki LlJ 0 .. ZYOSHIDA Koichi fi ffi 7t -**=Visiting Members
AOYAMA Shigeyoshi W LlJ Jf ~ (Kitami Inst. Technol.)(ICFD)ADACHI Shizuko 1i: Ji ~AHMADY Mohammad(Western Ontario Univ., Canada)
ARATANI Michi 5iL ~ ~ ~ (Inst. Environ. Sci.)
BOLBOT Michael(Notre Dame Univ. , USA)
BOYD Richard(Ohio Univ., USA)
BROCKMANN Roff (Inst. Phys. , Univ. Mainz, Germany)
CRUCCERU Ilie
(Horia Inst. Eng., Romania)
DATAR Vivek(Bhabha Atom. Res. Cen., India)
DAVID Dean J.
(CALTEC , USA)DEMYANOVA AlIa S.
(Kurchatov Inst. Atom. Energy, Russia)
DOKE Tadayoshi ~,~, ~(Adv. Res. Inst. Sci. Eng. , Waseda Univ.)
ENYO Yoshiko ~ W.1t
(Cen. Nucl. Study, Univ. Tokyo)
FOMITCHEV Andrei(JNRF, Russia)
FUJIWARA Mamoru ~ W~
(RCNP, Osaka Univ.)
FULOP Zsolt(ATOMIKI, Hungary)
GACSI Zoltan(ATOMKI, Hungary)
GEISSEL Hans
(GSI, Germany)
GIURGIU Mircea (Horia Inst. Nucl. Eng., Romania)
GOLOVKOV Mikhail S.
(Kurchatov Inst., Russia)
GONCHAROV Sergei A.
(Kurchatov Inst. , Russia)
GORINE Alexander (IHEO , Russia)
GOSWAMI Ranjana (Variable Energy Cycl. Cen. Calcutta, India)
GUNJI Shuichi
P] {I~ (Fac. Sci., Yamagata Univ.)
HASEBE Nobuyuki -R~:g:~1$1T (Fac. Sci. Eng. , Waseda Univ.)
NGUYEN THUC Hien
(Hanoi Univ. , Vietnam)

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HIRENZAKI Satoru ItJl~~ 'I~ (Fac. Sci., Nara Women's Univ.)
HORIGUCHI Masakatu #Hi 0 iE MJ (Horiguchi Ironworks)
HORIUCHI Hisashi #Hi P'J
7N! (Fac. Sci. , Kyoto Univ.)
IKEDA Kiyomi ?lli EEl ~l ~ISHIHARA Masayasu D}Jj( iE(RIKEN BNL Res. Cen.)(KEK)
ISHIMOTO Shigeru E 5C
ITAGAKI Naoyuki ti~ Z(Fac. Sci. , Univ. Tokyo)
IWAMOTO Akira E:;$:
BE (JAERI, Tokai Res. Estab.)
IWASA Naohito :E ft ~ 1= (Fac. Sci. , Niigata Univ.)
IWASAKI Aiichi :fi ~~ ~ (Nishogakusya Univ.)
IZUMIKAWA Takuji jJt}ll ~ P] (Fac. Sci. , Niigata Univ.)
IZUYAMA Takeo 1frR LlJfl~ (Fac. Sci. , Toho Univ.)
KANEKO Kazuya i: -=f-tl1 (Kyushu Sangyo Univ.)
KANUNGO Rituparna (Saha Inst. Nucl. Phys., Calcutta, India)
KATORI Kenji Ji[ ~ ~KIKUCHI Jun ~?ill
JII& (Sci. Eng. Res. Lab. , Waseda Univ.)
KIMURA Kikuo *tt%Y\1ift (Fac. Eng. , Nagasaki Inst. Appl. Sci.)
KOBAYASHI Toshio IJ'\ 1ft 1~ ftl (Fac. Sci. , Tohoku Univ.)
KOLATA James(Notre Dame Univ. , USA)
KOUZMINE Evgueni(Kurchatov Inst , Russia)
KRASZNAHORKAY Attila(ATOMKI , Hungary)
KUMARU Suresh(Bhabha Atom. Res. Cen. , India)
LE HONG Khiem(Inst. Phys. , Natl. Cen. Sci. Technol., Vietnam)
LIU Xin(Inst. Nucl. Study, Univ. Tokyo)
MARUYAMA Koichi :tL LiJ i~ (Inst. Nucl. Study, Univ. Tokyo)
MARUYAMA Tomoyuki :tL LiJ ~ ¥(Nihon Univ.)
MATSUOKA Nobuyuki tJ} It?iJ 1$ iT (RCNP, Osaka Univ.)
MATSUTA Kensaku tJ} ~ ~ rfi (Fac. Sci. , Osaka Univ.)
MATSUYAMA Yoshitaka tJ} LiJ 7i "4 (Inst. Nucl. Study, Univ. Tokyo)
MINAMISONO Kei ~ IJJ§(Fac. Sci. , Osaka Univ.)
MINAMISONO Tadanori 1¥J IJJ ,[I,]:lU (Fac. Sci. , Osaka Univ.)
MITTING M.
(GANIL , France)
MIHARA Mototugu =: }Jj( £ Iffl~ (Fac. Sci. , Osaka Univ.)
MIRGULE Ekanath Tanu
(Bhabha Atom. Res. Cen. , India)
fIJi (Fac. Sci., Univ. Tsukuba)
MIYAKE Yasuo = ~MIYAMURA Osamu '8 ft
11t (Fac. Sci. , Hiroshima Univ.)
MOMOTA Sadao 8EEl1ft:~~ (Kochi Univ. Technol.)
MORITA Hiroaki ~ EEl ~t. Ejj (Horiguchi Ironworks)
MURAOKA Mitsuo tt It?iJ 7t:!J5 (Fac. Eng., Aomori Univ.)
NOJIRI Yoichi lff JJL i$ (Kochi Univ. Technol.)
NOMURA Izumi lff tt
jJt(NIFS)
OGAWA Kengo IJ'\ Jllfl::g. (ColI. Arts. Sci. , Chiba Univ.)
OGAWA Yoko IJ'\}II i$(Fac. Sci., Osaka Univ.)
OGLOBLIN Alexei A.
(Kurchatov. Inst. , Russia)
OHTSUBO Takashi -)( if~i(Fac. Sci. , Niigata Univ.)
OMATA Kazuo IJ'\ 1~~(Inst. Nucl. Study, Univ. Tokyo)
ORYU Shinsho ~ JL. 1!f r$ (Fac. Sci. Technol. , Sci. Univ. Tokyo)
OTSU Hideaki -)( if~(Fac. Sci. , Tohoku Univ.)OTSUKA Takaharu -}(:t~"4 16 (Fac. Sci. , Univ. Tokyo.)OYAMATSU Kazuhiro ~1 tli~(Aichi Shukutoku Univ.)
PETRASCU Horia(Horia Inst. Phys. Nucl. Eng. , Romania)
PETRASCU Marius(Horia Inst. Phys. Nucl. Eng., Romania)
POLLACCO Emmanuel(EAC , France)
ROUSSEL-CHAMAZ P.
(GANIL , France)
SAGAWA Hiroyuki 1ft: )11 ~t. ¥(Cen. Math. Sci., Univ. Aizu)
SAKAGUCHI Harutaka :t& 0 16 ~i (Grad . Sch., Kyoto Univ.)
SAKAI Hideyuki i@ if 1i: iT (Fac. Sci. , Univ. Tokyo)

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SAKURAI Hirohisa tf # ~ 0. (Fac. Sci., Yamagata Univ.)
SASA Hiromasa 1t 4 t-f i& (Horiguchi Ironworks)
SATO Hiroshi 1t Ii
ff.k (Seikei Univ.)
SATO Kazuhiro 1t Ii *O?.f: (Tokyo Fire Dept.)(GANIL, France)
SAVAJOLS H.
SCHROEDER Lee S.
(Laurence Berkeley Lab. r USA)
SEKI Ryoichi I'Ml
7C (California Univ. , USA)
(Michigan State Univ. , USA)SHERRIL B.
SHIBATA Mitihiro ~ E8 :00 ~ (Dept. Energy Eng. Sci., Nagoya Univ.)
SHIBATA Toru ~ E8
11& (Sci. Eng. , Aoyama Gakuin Univ.)
SUGANUMA Hideo ;g:fi; ~ (RCNP, Osaka Univ.)
SUGAWARA Masahiko ;g:)}j( ~ j¥J (Fundam. Sci. , Chiba Inst. Technol.)
SUMMERER Klaus(GSI, Germany)Z (KEK)SUZUKI Hideyuki jiJ
SUZUKI Takeshi ~iJ
1l (Fac. Sci., Niigata Univ.)
SUZUKI Tsuneo jiJtg(Fac. Sci. , Kanazawa Univ.)
fW. 515 (Sci. Eng., Fukui Univ.)
SUZUKI Toshio jiJ
SUZUKI Yasuyuki jiJ'§" Z(Fac. Sci., Niigata Univ.)
TACHIBANA Takahiro f~[@j t-f (Sen. High Sch., Waseda Univ.)~ ¥(Alabama Univ., USA)
TAKAHASHI Yoshiyuki [@jTAKAHASHI Yutaka ~-=- (Fac. Sci. , Osaka Univ.)
TAKANO Masatoshi • If iE *U (Fac. Sci. Eng., Waseda Univ.)
TER-AKOPIAN G.
(Dubna, Russia)
THIROLF P.
(Univ. Munchen, Germany)
TOKANAI Fuyuki r~ pt ~ tit (JST)TOKI Hiroshi ± Ii&:
t-f (RCNP, Osaka Univ.)TORBJOEN Baeck (Stockholm Univ., Sweden)
TOSTEVIN Jeffrey A.
(Univ. Surry, India)
UCHIHORI Yukio I*J ffil ¥ ~ (Inst. Rad. Sci.)
UTSUNO Yutaka *iflf fll (Tokai Research Establishment)
UTSUNOMIYA Hiroaki *~~8~.k$: (Fac. Sci. , Konan Univ.)
VARGA Kalman(Inst. Nucl., Hungarian Acad. Sci. , Hungary)
WADA Takahiro *0 E8 ~i 7.i (Fac. Sci., Konan Univ.)
WINKLER Martin(GSI, Germany)
YAGI Hirosuke }\¥~ 'ifi(Fac. Sci. , Univ. Tsukuba)
YAMADA Shoichi LIJ E8(Fac. Sci. , Univ. Tokyo)
YAMAGUCHI Yoshio LIJ 0 & ~ (Inst. Nucl. Study, Univ. Tokyo)
YORANN Alhassid(Yale Univ. , USA)YUZUKI Akira tm~(Toshiba Corp.)
ZAHAR Mohamed(Dept. Phys., Notre Dam Univ. , USA)ZHENG Tao
(Fac. Sci. Technol. , Sci. Univ. Tokyo)m*** *a**mm* -= -**

Trainees
AOKI Yuka W EE W (Fac. Sci. , Tohoku Univ.)
CHIBA Masami T ~ ~~ 7C (Fac. Sci. , Tohoku Univ.)
FUZIMURA Takeshi Ii ft-ffi (Sci. Eng., Aoyama Gakuin Univ.)
HARA Kenichiro )}j( ~ - f!Jj (Fac. Sci. Eng., Waseda Univ.)
HARUKI Masamichi
iE ~ (Fac. Sci. Eng., Waseda Univ.)
HIBINO Masaru B ltlff 11 (Fac. Sci. Eng., Waseda Univ.)
IHARA Akifumi #'*£1[*'2.9:: (Fac. Sci. Eng., Waseda Univ.)
HASHIMOTO Izumi*0 jj:t (Fac. Sci., Osaka Univ.)
ITO Hiroshi 1¥ Ii ¥~ E (Fac. Sci. Eng. , Waseda Univ.)
KATO Tomomi :Do Ii 1r ~ (Fac. Sci., Niigata Univ.)
KATO Toshiyuki :Do Ii 1~ ¥(Fac. Sci. Eng., Waseda Univ.)
KAWA Tadahisa iPJ,~, 0.
(Fac. Sci., Osaka Univ.)
KAWAMURA Yoshie 111 ft ~ ~ (Fac. Sci. Niigata Univ.)
KIHIRA Eiichi fi(Fac. Sci. Eng. , Waseda Univ.)

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KITANI Takao *:fr"(Fac. Sci. Eng., Waseda Univ.)
KIYAMU Atushi %:frm:~9:. (Fac. Sci. Eng., Ibaraki Univ.)
KOBAYASHI Shingo fj_
Ji ft (Fac. Sci. Eng., Waseda Univ.)
KOIKE Takayuki fj-?ill"" Z(Fac. Sci. Eng., Waseda Univ.)
KUDO Syuichi I Ri fl~ (Fac. Sci., Osaka U niv.)
KURIYAMA Koji W: LlI ¥ ¥B (Sci. Eng., Aoyama Gakuin Univ.)
MASUMURA Takahiro ±~ ft ~ i$ (Fac. Sci. Eng., Waseda Univ.)
MIYAKE Toru =: ~f1& (Fac. Sci., Osaka Univ.)
MUTO Nobuo m: Ri 1§ it (Fac. Eng., Aoyama Gakuin Univ.)
NAGATOMO Kiyoshi :Ii: 1ft:.
~(Fac. Sci., Osaka Univ.)
NISHIKIDO Humihiko ~ p )( rJj (Fac. Sci. Eng., Waseda Univ.)
OGURA Masako fj_ ~ ~ -T (Fac. Sci., Osaka Univ.)OHZEKI Kazuki ]( M fo" (Fac. Sci., Tohoku Univ.)
OKA Aihiro ffliJ
3t ~L (Fac. Sci. Eng., Waseda Univ.)
OKUDA Takashi ~ ffi .. i1t (Fac. Sci., Tohoku Univ.)
OKUDAIRA Osamu J!: ~fl~(Fac. Sci. Eng., Waseda Univ.)
OZAKI Kiminori fit. W* 0 ~ (Fac. Sci. Eng., Waseda Univ.)
SAKAGUCHI Takao :t& 0 .... ~ (Fac. Sci. Eng., Waseda Univ.)
SASAKI Makoto 1£ 4
IDOC (Fac. Sci., Osaka U niv.)
SATO Kazunori 1£ Hi fo ~u (Fac. Sci., Osaka Univ.)
SEKIGUCHI Masatugu M 0 ~ fffim (Fac. Sci. , Tohoku Univ.)
SHIMIZU Noritaka rt 7)( ~Ij ~ (Fac. Sci., Univ. Tokyo)
SOURI Hirofumi ~*flj§:9:. (Fac. Sci. Eng., Waseda Univ.)
SUGIMOTO Satoshi if~~~(RCNP, Osaka Univ.)
TAKEMURA Atsushi tT ft
j~(Fac. Sci., Osaka Univ.)
fL (Fac. Sci. Eng., Waseda Univ.)
TAKEMURA Haruyuki tt ft
TAKENAKA Sunao tT 9='~(Fac. Sci. Eng., Waseda Univ.)
TAKENOUCHI Masatoshi tTzl*JiE1~ (Fac. Sci. Eng., Waseda Univ.)
TAKEUCHI Satoshi m: lAJ~~(Fac. Sci., Rikkyo Univ.)
TANAKA Motoyuki EB 9=' £ Z (Fac. Sci., Waseda Univ.)
TAZAWA Shinya ffi ¥R 1$ ill (Fac. ScL, Tohoku Univ.)
TERASAWA Kazuhiro =tf rR fo i$ (Fac. Sci. Eng., Waseda Univ.)
TERASAWA Mariko =tfi*J{~-T (Fac. Sci., Univ. Tokyo)
TERUHI Shigeru P.R B~(Fac. Sci. Eng., Waseda Univ.)
UMEMURA Tomohiro t~ ft m~ ~L (Fac. Sci. Eng. , Waseda Univ.)
UZIIE Toru .E\:;
11& (Fac. Sci., Tohoku Univ.)
WAKASAYA Yoshiaki E~~:fr~aJ:l (Fac. Sci. Technol., Sci. Univ. Tokyo)
WANG Haiming .:E
7~ qllb(Fac. Sci., Univ. Tokyo.)
WATANAE Shigeo iJi jJ 1f ~ (Fac. Sci., Niigata Univ.)
YAMADA Kazunari LlI ffi - pj(: (Fac. Sci., Rikkyo Univ.)
YAMAGUCHI Yoshitaka LlJ 0 EE ~ (Fac. Sci., Niigata Univ.)
YAMASHITA Masaki LlI T ~ fit (Adv. Res. Inst. Sci. Eng., Waseda Univ.)
YAMASHITA Naoyuki LlI T ~ Z (Fac. Sci. Eng., Waseda Univ.)
it i$: (Fac. Sci. Eng. , Waseda Univ.)
YASHIRO Junichi
YOSHIOKA Hideki E ffliJ:fit (Fac. Sci. Eng., Waseda Univ.)

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Applied Nuclear Physics Laboratory
Head
ASAHI Koichiro 1@ fjf:- rm
Members

KOBAYASHI Yoshio
SATO Wataru 1£ Ri
YOSHIMI Akihiro E J! ~ i$

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UEN 0 Hideki .l. ff:fit
YONEDA Kenichiro *EB. - ~~WATANABE Hiroshi iJi jJ
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Visiting Members
EINAGA Yasuaki
l3Jj (Fac. Sci., Univ. Tokyo)
1M AI Nobuaki A, it 1$ l3Jj (Fac. Sci., Univ. Tokyo)
KUBO M. Kenya ~ 1:* ~ ijz (Fac. Sci., Univ. Tokyo)
OGAWA Hiroshi IJ'\}l1 tt!j: Iffl~ (Fac. Sci., Tokyo Inst. Technol.)
SAKAI Kenji i~ it 1l(Fac. Sci., Tokyo Inst. Technol.)
YAMADA Yasuhiro LlJ e3
it (Fac. Sci., Sci. Univ. Tokyo)
NAKAHARA Hiromichi 9=J mt ~L. JH (Fac. Sci., Tokyo Metrop. Univ.)
SHIMIZU Suguru
71<.
~(Fac. Sci., Osaka Univ.)
ADACHI Minoru JE~
OKADA Takuya ItliJ e3 !j[ ill

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1f. ¥ (Fac. Sci., Tokyo Inst. Technol.)
SUGA Toshitaka ~Jt ~ 1W. ~ (Fac. Sci., Tokyo Inst. Technol.)
YOGO Katsunori ~ ~g. 52: ff.2. (Fac. Sci., Tokyo Inst. Technol.)
GOTO Atsushi Ii ~~X
(Fac. Sci., Tokyo Inst. Technol.)
HONDA Toshiki~ f~;fit(Fac. Sci., Tokyo Inst. Technol.)
HORI Kentaro #ill 1l*~~ (Fac. Sci., Sci. Univ. Tokyo)
KATSUMATA Keiichi M¥ X ~ (Fac. Sci., Sci. Univ. Tokyo)
MIYAZAKI Junn g Iil~
j.!j!.
(Fac. Sci., Sci. Univ. Tokyo)
MIYOSHI Hisanori := ~f jK:g (Fac. Sci., Tokyo Inst. Technol.)
KAMEDA Daisukee3'llf (Fac. Sci., Tokyo Inst. Technol.)
NAGAKURA Masaki~ lE;fit(Fac. Sci., Tokyo Inst. Technol.)
SATO Keisuke 1ft: Jii.
Jr (Fac. Sci., Tokyo Inst. Technol.)
OONO Kenichi
ff ~ (Fac. Sci., Tokyo Inst. Technol.)
KAIHARA Jou ffiJ. mt }£(Fac. Sci., Tokyo Inst. Technol.)
OGAWA Shigeru IJ'\}l1(Fac. Sci., Shizuoka Inst. Sci. Tech.)
ONO Yuki IJ'\ ff f-b;fit (Fac. Sci. , Sci. Univ. Tokyo):* (Fac. Sci., Sci. Univ. Tokyo)
SAITO Takashi ~ Jii.
SHIMAZAKI Hideo ~ Iil~ 3'1; ~ (Fac. Sci., Sci. Univ. Tokyo)
ISHIKAWA Yumiko 1]JII E8~r (Fac. Sci., Sci. Univ. Tokyo)
SHIMIZU Yasunori ~.- 71<.
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Head
YAMAZAKI Yasunori LlJ Iil~

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IKEDA Tokihiro ng e3 ~ i1!f
KANAI Yasuyuki i: it 1:* Z
MORISHITA Yuichiro ~Tftl - ~~NAKAMURA Takashi 9=J ft .. ~NISHIMURA Tamio W ft .§!; ~OURA Masaki
lE ;fitSHIMAMURA Isao ~ ft~
TERANISHI Yoshiaki ~ W 1§"

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KOJIMA Takao M. IJ'\ ~ ~i ~NAKAI Yoichi 9=J # 1% NISHIDA Masami W ill ~ ~OSHIMA Nagayasu
lEJ jKOYAMA Hitoshi
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TAKEKAWA Michiya it]ll JH ill
WAD A Michiharu ;to 83 JH 16

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Visiting Members
ANDO Kozo 1; Ei Ilfillj
AZUMA Toshiyuki
f~ 1T(Dept. Phys., Tokyo Metrop. Univ.)
BRAGE Tomas(Dept. Phys. , Univ. Lund, Sweden)
CHIMI Yasuhiro 920 J!
~L.
(JAERI, Tokai Res. Estab.)
DIAO Xungang ?J
WI! Ilfillj (Shizuoka Inst. Sci. Tech.)
DUMITRIU Dana (Natl. Inst. Phys. Nucl. Eng., Romania)
EICHLER Jorg
(Hahn-Meitner Inst. Berlin, Germany)

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417

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FAIFMAN Mark
(Russian Res. Cent., Kurchatov Inst., Russia)
FUJIMA Kazumi ni Fa' (Fac. Eng., Yamanashi Univ.)
13t 1r (Dept. Gen. Ed. , Tsukuba CoH. Technol.)
HARA Shunsuke
HATTORI Toshiyuki m~!~ 1~ ¥(Res. Lab. Nucl. React., Tokyo Inst. Technol.)(Inst. Appl. Phys., Univ. Tsukuba)
HINO Ken-ichi . B 1ff ~ HITACHI Akira Jj tB:$': (Kochi Med. Sch.)
HUTTON Roger(Dept. Phys., Lund Univ., Sweden)
ICHIMURA Atsushi
ft {!f- (Inst. Space Astr. Sci.)
ICHIOKA Toshiyasu
IRiJ flj(Grad. Sch. Arts Sci., Univ. Tokyo)
IGARASHI Akinori 1L+;~()IJHW (Fac. Eng., Miyazaki Univ.)t~(Univ. Tsukuba)
IKEDA Hiroshi rtf! H3
INOKUTI Mitio # D J:g ~ (Argonne Natl. Lab., USA)ISHII Keishi :0 # !t Z (Fac. Sci. Eng., Ritsumeikan Univ.)
ISHIKAWA Norito :0 JII 1t A (JAERI, Tokai Res. Estab.)
ITO Takaomi f]T ni ~ b! . (Grad. Sch. Arts Sci., Univ. Tokyo)
ITOH Akio f]T ni t;k ~ (Fac. Eng., Kyoto Univ.)
ITOH Yoh 1t'" ni~~(Fac. Sci., Josai Univ.)
IWAI Yoshio :E # .N.:1: (Dept. Phys., Grad. Sch. Sci. , Univ. Tokyo)
IWASE Akihiro :E ifli ~ 1.i. (JAERI , Tokai Res. Estab.)
KAGEYAMA Kensuke Ii LlI ~ 1r (Fac. Eng., Saitama Univ.)
KAWATSURA Kiyoshi JlI 00
1i (Fac. Eng. Design, Kyoto Inst. Technol.)fj ~(Fac. Eng., Kyoto Univ.)
KIMURA Kenji
KIMURA Mineo
fj ~ (Fac. Eng., Yamaguchi Univ.)
KITAJIMA Masashi ~t lifb ~ 5t:. (Fac. Sci. Technol., Sophia Univ.)
KOBAYASHI Nobuo IJ'\ ift 1~:1: (Dept . Phys. , Tokyo Metrop. Univ.)
KOIKE Fumihiro IJ'\ itP. )( t~ (Sch. Med., Kitasato Univ.)
KOIZUMI Tetsuo IJ'\ ~ tg- ~ (Dept. Phys., Rikkyo Univ.)
KOMAKI Ken-ichiro IJ'\tl~JiJf-~~ (Grad. Sch. Arts Sci., Univ. Tokyo)
KOWARI Kenichi IJ'\ ~U ~ (Dept. Appl. Phys. Chern., Univ. Electro-Commun.)
KURODA Naoshi ~ H3 @:;t: (JAERI, Tokai Res. Estab.)
KUROKI Kenro ~1l f!~ (N atl. Res. Inst. Police Sci.)
LINDROTH Eva(Dept. Atom. Phys., Stockholm Univ., Sweden)
MATSUNAMI Noriaki t~ ill if.2. 13)3 (Sch. Eng., Nagoya Univ.)
MATSUO Takashi t~ ~(Dept. Pathol., Tokyo Med. Dent. Univ.)
MATSUZAWA Michio tl if :im ~ (Dept. Appl. Phys. Chern. , Univ. Electro-Commun.)
MITSUKE Koichiro ~J#~ - f!~ (Inst. Mol. Sci.)
MIZOG AWA Tatsumi i1i-)II J.OC E (N agaoka ColI. Technol.)M 0 HRI Akihiro ~ flJ 13)3 t~
MUKOYAMA Takeshi [QJ LlI~(Inst. Chern. Res., Kyoto Univ.)
OHTANI Shunsuke
13t 1r (Inst. Laser Sci., Univ. Electro-Commun.)
OKABAYASHI Norio IRiJ ift ~1j:1: (Grad. Sch. Arts Sci., Univ. Tokyo)
OKADA Kunihiro IRiJ H3 f~ 1.i. (Fac. Sci. Tech., Sophia Univ.)
OKAYASU Satoru IRiJ Y:'It- (JAERI, Tokai Res. Estab.)
OKUNO Kazuhiko Jb 1ff$(Dept. Phys., Tokyo Metrop. Univ.)
ONO Fumihisa IJ'\ 1ff )().... (Dept. Phys., Okayama Univ.)
ROSMEJ Frank B.
(GSI, Germany)
SAKAI Akio ~ # BB:1: (Vacuum Products Co.)
SATO Hiroshi 1t JIi i11r 5t:. (Fac. Sci., Ochanomizu Univ.)
SHIMA Kunihiro lifb
f~ t~(Tandem Accel. Cen. , Univ. Tsukuba)
SHIMAKURA Noriyuki lifb ~ *2, Z (Fac. Sci., Niigata Univ.)
TONUMA Tadao p rg 1£ a (Adv. Res. Inst. Sci. Eng. , Waseda Univ.)TORII Hiroyuki ,~m ~ Z (Grad. Sch. Arts Sci., Univ. Tokyo)
TOSHIMA Nobuyuki p i\J,~ 1~ ¥(Inst. Appl. Phys., Univ. Tsukuba)
TSUCHIDA Hidetsugu ± H3
(Fac. Sci. , Nara Women's Univ.)
UEDA Kiyoshi 1:. H3i~(Res. Inst. Sci. Meas., Tohoku Univ.)
WATANABE Shinichi ill ill f~ (Dept. Appl. Phys. Chern., Univ. Electro-Commun.)
YAGISHITA Akira t~p T
13)3
(KEK)

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418

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YOSHIDA Yutaka E EEl(Shizuoka Inst. Sci. Tech.)ZOU Yarning(Shanghai Jiao Tong Univ., China)
Trainees
EBIHARA Takashi i~~JJj(.1§I] (Fac. Sci. Technol., Sophia Univ.)
ENDO Atsumi ii Xi J!I.:!lt (Dept. Phys., Grad. Sch. Sci., Univ. Tokyo)
HASEGAWA Tadayuki -R~JIj}~,z (Grad. Sch. Eng., Tokai Univ.)iE fij (Dept. Phys., Grad. Sch. Sci., Univ. Tokyo)
HORI Masaki #lli
HOSHINO Masamitsu .£ ff lE 7t (Grad. Sch. Sci. Eng., Sophia Univ.)
KURODA Naofumi ~ EEl 1l 9:. (Dept. Phys. , Grad. Sch. Sci., Univ. Tokyo)
MAJIMA Takuya Fa' U!~ 11] ill (Grad. Sch. Eng., Kyoto Univ.)
MURAKOSHI Dai f;J ~-}( (Grad. Sch. Arts Sci., Univ. Tokyo)
NIIGAKI Megumi %'JT iH
Nl- (ColI. Arts Sci., Univ. Tokyo)
OSHIMA Tatsuaki -}( ~ Ii~ ~ (Grad. Sch. Sci., Tohoku Univ .)SAKAGUTI Syuiti :tN 0 {I~ (Grad. Sch. Sci. Tech., Saitama Univ.)
SHIMADA Hiroyuki ~ EEl *1L 1T (ColI. Arts Sci., Univ. Tokyo)
SONODA Tetsu III EEl:1'& (Grad. Sch. Sci., Tohoku Univ.)
TAKABAYASHI Yuichi iW:i(Dept. Phys. , Grad. Sch. Sci., Univ. Tokyo)
TAKAHASHI Takehisa iW:i ~~(Dept. Phys. , Grad. Sch. Sci., Rikkyo Univ.)** m:a -Muon Science Laboratory
Head
NAGAMINE Kanetada

7K ~ ~ ,'iL',

Members
BAKULE Pavel
HASHI Kenjiro ~iffl ~=f1~
KAWAMURA Naritoshi iilJ f;J pJt ~MATSUDA Yasuyuki t~ EEl¥
MATSUZAKI Teiichiro t~lijft~mf1~
OHIRA Seiko~ ~STRASSER Patrick
YAGI Eiichi )\

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ISHIDA Katsuhiko :fi EEl 1m ~KOYAMA Akio IJ . . LlJ BB a
MATSUSHITA Akira fi} T~
NAKAMURA Satoshi N. q:t f;J
PRATT Francis L.
WATANABE Isao iJi jJ Jj]aVisiting Members
ADROJA Devashibhai(Fac. Sci., Hiroshima Univ.)
AJIRO Yoshitami *~ it 7i.a: (Fac. Sci., Kyushu Univ.)
AKIMITSU Jun f* 7t*~(ColI. Sci. Eng., Aoyama Gakuin Univ.)
5'2: i$ (Inst. Mater., Univ. Tsukuba)
AKIMOTO Katsuhiro f*
AKOSHIMA Megumi ~ilJ r~66 <" h- (Fac. Eng. , Tohoku Univ.)
ARAI Juichiro %'Jf#:m: - ~~ (Sci. Univ. Tokyo)
ASAI Kichizo i~ # E iii (Univ. Electro-Commun.)
AWAGA Kunio ~ilJ¥lt~ J:~~ (Grad. Sch. Arts Sci., Univ. Tokyo)
BOGDANOVA N. Ludmila(Inst. Theor. Exp. Phys., Russia)
BRIERRE Tina M.
(KEK)
BROWN Douglas H.
(KEK)
DAS Prasad Tara
(Dept. Phys., State Univ. New York, Albany, USA)
FUJIOKA Manabu Xi ItliJ
5f. (Cycl. Radioisot. Cen., Tohoku Ulniv.)
FUKUSHIMA Kenji tli?i ~ ~HIGEMOTO Wataru t~
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(KEK)
HONDA Morihiro
EEl ~ Jt.. (Inst. Cosmic Ray Res., Univ. Tokyo)
HIYAMA Emiko ~~LlJMc~r (KEK)
IKEDA Susumu 7th EEl:i1t (KEK)ITO Atsuko {ft iIi J!I.
IWASAKI Masahiko :E ilJ~ ~ ~ (Dept. Phys., Tokyo Inst. Technol.)
KADONO Ryosuke r~ ff .& ~ (KEK)

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KAMIMURA Masayasu L tt iE(Fac. ScL, Kyushu Univ.)
Hi ~ 4: (JAERI, Tokai Res. Estab.)
KATO Mineo
KINO Yasushi
ff~(Fac. Sci., Tohoku Univ.)
KOIKE Youji IJ'\ 7lli i$(Fac. Eng.; Tohoku Univ.)
KUNO Yoshitaka ~ H .&:Jf. (KEK)
KUROSAWA Kiyoyuki ~ iR 1w 1-1 (JAERI, Tokai Res. Estab.)(Notre Dame Radiation Lab., USA)
MACRAE Roderick M.
MAKIMURA Syunsuke ~ tt f3f: !tJJ (KEK)(KEK)
MARUTA Goro JL E8 Hf;:r (Fac. Eng., Fukui Univ.)
MEKATA Mamoru § 11
MINAMISONO Tadanori T¥J [I] ,~, ~Ij (Fac. Sci., Osaka Univ.)
tt (KEK)MIYAKE Yasuhiro =: ~fM 1= (Fac. ScL, Osaka Univ.)
MIYAKO Yoshihito t~
MOCHIKU Takashi a m~ ± (Natl. Res. Inst. Metals)
MORITA Masato ~ EE iE A (Fac. Sci. , Josai Univ.)
MORITA Reiko ~ EE 1% -T (Josai Jr. ColI. Women)
NISHIDA Nobuhiko W EE 19 ~ (Fac. Sci., Tokyo Inst. Technol.)NISHIYAMA Kusuo W LlJ ff 4: (KEK)
PONOMAREV Leonid 1.
(Kurchatov Inst., Russia)
SAKAMOTO Shinichi t& 5C !J! (KEK)
SATO Kazuhiko ft Mi - ~ (Fac. Sci., Saitama Univ.)
SHIMOMURA Koichiro Ttti15-fJ~ (KEK)
STORCHAK Vyacheslav G.
(Kurchatov Inst., Russia)
SUGAI Hiroyuki ~J J! 1i 1-1 (JAERI, Tokai Res. Estab.)
TAKABATAKE Toshiro ~ ~ fi& fJ~ (Grad. Sch. Adv. Sci. Matter, Hiroshima Univ.)
TAKEDA Keiji
E8 § P] (Hokkaido Univ.)
1= (Inst. Solid State Phys.)
TAKIGAWA Masashi ilJ~}l1
TANASE Masakazu fJill ~ lE *0 (JAERI, Takasaki)
TORIKAI Eiko ,~:if ~ -T (Fac. Eng., Yamanashi Univ.)
UEDA Kazuo L EE *O::t: (Inst. Solid State Phys.)
UMEO Kazunori 1~ fif. *0 ~Ij (Fac. Sci., Hiroshima Univ.)
WADA Nobuo *0 E8 fg(Grad. Sch. Arts Sci., Univ. Tokyo)
1J (Int. Chr. Univ.)
WATANABE Tsutomu ill:g:~
YAMADA Kazuyoshi LlJ E8 *0 7i (Inst. Chern. Res., Kyoto Univ.)

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MIYAD ERA Haruo g =#= BR ::t: (Grad. Sch., Univ. Tokyo)(Grad. Sch., Nagoya Univ.)
TANAKA Hiroyuki EE ~ 1i ¥TOYODA Akihisa .:. EE :1b ~ (Grad. Sch., Univ. Tokyo)

Magnetic Materials Laboratory
Head
KATSUMATA Koichi Mf X {fft Members
HAGIWARA Masayuki**-)Jj( i& ¥MATSUDA Masaakit} EE ~ ~Beam Physics and Engineering Laboratory
Head
KATAYAMA Takeshi h LlJ
R]m:Members
CH 0 UFFANI Khalid
NAKAMURA Masato ~ tt 1= i§OKAZAKI Kiyohiko \iliJ1iJ~1wlt~

420

HAMAGAKI Manabu ifr- t~~
OKAMURA Masahiro \iliJ tt ~ 1i
SAKUMI Akira it ~~

TAKANAKA Masao ~ 1$ i& it
WATANABE Tamaki iJi jI~YANAGISAWA Yoshiyuki 1~P~ 1T
YUN Chong-Cheoul jt
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TAMBA Moritake ft ¥&: ~i m:
XIAO Meiqin ~~ ~YOKKAICHI Satoshi 1m B m '1%

Visiting Members
BOLSHAKOV Alexander(ITEP, Russia)
CHAI Jong-Seo(CALK, Korea)
DIKANSKI Nikolai(Budka Inst. Nucl. Phys. , Russia)
HARA Tamio~ ~(Toyota Technol. Inst.)(Canon Inc.)HASHIMOTO Yuichi m hi (Res. Lab. Nucl. React., Tokyo Inst. Technol.)
HATTORI Toshiyuki m~ ~~ ~ ¥JAMESON Robert(Los Alamos Natl. Lab., USA)
KATO Shigeki nD Hi
fM (KEK)KOCHKAREV Dmitry(ITEP, Russia)
KONDRASHEV Sergei(ITEP, Russia)
KOROTAEV Iouri(JINR, Russia)
MATSUMOTO Takashi ti} 5C it ~ (CNS , Univ. Tokyo)
MESHKOV Igor
(JINR, Russia)
MOON Sang-ik(CALK, Korea)
OGAWA Masao IJ'\)l1 ~ ~ (Tokyo Inst. Technol.)
OGURI Yoshiyuki IJ'\ ~ ~ Z (Res. Lab. Nucl. React. , Tokyo Inst. Technol.)
SAKAKIBARA Takeshi #$IMlIJ(Chuo Univ.)hi (Nichimen Co.)
SAKAMOTO Yuichi :t&
SERATA Masaki -tit HEBJO¥: (CoIl Sci., Rikkyo Univ.)
SHARKOV Boris(ITEP, Russia)
SIDORIN Anatoly (JINR, Russia)
SKRINSKY Alexander(ITEP, Russia)
SYRESIN Evgeny(JINR, Russia)
TAKEUCHI Takeshi
I*J 3i (CNS, Univ. Tokyo)
YUKITAKE Mitsuteru ~Jt(Hitachi Ltd.)ZENKEVITCH Pavel(ITEP, Russia)
GALSTER Wilfried(CNS , Univ. Tokyo)
HAMAGAKI Hideki i~fit (CNS, Univ. Tokyo)
HIRANO Midori ifff""t~ ~(CNS, Univ. Tokyo)(CNS , Univ. Tokyo)
KOHNO Kiyoji iPJ If 1~
KUBONO Shigeru j.J*1f Dt (CNS , Univ. Tokyo)
KUBOTA Shogo j\f*EB~~ (CNS , Univ. Tokyo)-'if. (CNS, Univ. Tokyo)
MIYACHI Takashi '8:i=lli.
(CNS, Univ. Tokyo)
NISHIMURA Shunji [!3 ft ~NOTANI Masahiro ff ~ ~q. rt (CNS , Univ. Tokyo)~ ¥ 7t(CNS , Univ. Tokyo)
OHSHIRO Yukimitsu
OZAWA Kyoichiro IJ'\rR~ - ~~ (CNS, Univ. Tokyo)(CNS , Univ. Tokyo)
SAKAGUCHI Takao :t& 0
SHIMOKOSHI Fumio~ ;i: ~(CNS , Univ. Tokyo)
SHIMOURA Susumu -r imc!F (CNS, Univ. Tokyo)
TAKAKU Seisaku ~ -A 7~ it (CNS, Univ. Tokyo)
TANAKA Yoshito EB q:t • A (CNS , Univ. Tokyo)
TERANISHI Takashi ::!f [!3~(CNS , Univ. Tokyo)
UESAKA Meiko .l:t& ~(CNS , Univ. Tokyo)
WATANABE Shin-ichi iJi :i2l1$ (CNS, Univ. Tokyo)
YAMAMOTO Yasushi LlJ(CNS, Univ. Tokyo)
YAMAZAKI Norio LlJ Ill~ ~Ij ~ (CNS , Univ. Tokyo)

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Cellular and Molecular Biology Laboratory
Head
SHIBATA Takehiko ~ ffi m:mMembers
LING Feng~~

Cellular Physiology Laboratory
Head
HANAOKA F'urnio 1t. IiYi1 Y:.

aMembers
YATAGAI F'urnio~ffi~Y:.~

Visiting Members
ANDO Koichi 1;: Ji. ~ (Natl. Inst. Radiol. Sci.)
FURUSAWA Yoshiya [jt!1 (Natl. Inst. Radiol. Sci.)
HAM A Yoshirnasa i~~ J§(Sci. Eng. Res. Lab., Waseda Univ.)
HASE Yoshihiro :&:a- *if!: 7i (JAERI, Takasaki Rad. Chern. Res. Estab.)
HOSHINO Kazuo £ ~ - tl (Natl. Inst. Radiol. Sci.)
ITO Hisao 1fr"* 0. ~ (Sch. Med., Chiba Univ.)
ITS UKAI CHI Hirorni .li B rtF} .0 c1}. (N atl. Inst. Radiol. Sci.)
KANAI Tatsuaki ~ # Ji ~ (Natl. Inst. Radiol. Sci.)
KASAl Kiyorni j£ # r.. ~ (Natl. Inst. Radiol. Sci.)
KAWACHI Kiyornitsu illJ I*J rff 7t (N at I. Inst. Radiol. Sci.)
KOBAYASHI Yasuhiko /J"~(JAERI, Takasaki Rad. Chern. Res. Estab.)
MATSUFUJI Naruhiro {~Ji. nX: ~t. (Natl. Inst. Radiol. Sci.)MINOHARA Shinichi ~}Jj( 1$ (Natl. Inst. Radiol. Sci.)
MURAKAMI Masahiro ft 1::. lE ~t. (Natl. Inst. Radiol. Sci.)
SAITO Mizuho 1f Ji. 100 ~ (Natl. Inst. Radiol. Sci.)
SASAKI Hiroshi 1t4* ~t. (Fac. Med., Kyushu Univ.)
SHIKAZONO Naoya Jl ~ Il ~ (JAERI, Takasaki Rad. Chern. Res. Estab.)
SOGA F'urninori ~;ft Y:. if (Inst. Nucl. Study, Univ. Tokyo)
TANAKA Atsushi ffi if'i¥ (JAERI, Takasaki Rad. Chern. Res. Estab.)
TOMURA Hirorni ~ ft i1!i ~ (Natl. Inst. Radiol. Sci.)
WATANABE Masarni iJi illlE(Fac. Pharrn. , Nagasaki Univ.)
YAMASHITA Shoji LLr T J§
(Natl. Saitarna Hospital)

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LI Ryonpha

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Plant Functions Laboratory
Head
YOSHIDA Shigeo E ffi ~ !!J3
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ABE Tornoko ~ilJ g:~ 92D
SAKAMOTO Koichi ~Nr* i1!i -=MATSUYAMA Tornoki{~Li.J 92D ;fit

Visiting Members
FURUKAWA Koji [j]ll r1!i
(Mukoyarna Orchids Ltd.)HAMATANI Misako i~:a-~ft r(Hiroshima City Agric. Forest. Prornot. Cen.)
HARA Yasuhide }Jj(~~ ~(Kanagawa Inst. Agric. Sci.)
HASHIMOTO Takashi ;{i~i(Dept. Biosci., NAIST)HONDA Ichiro~~~(N at I. Agric. Res. Cent., MAFF)

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422

KITAURA Takeo ~r.?m 1l ~ (Kanagawa Inst. Agric. Sci.)
MIYOSHI Kazumitsu .=-: E - -Jt (Fac. Bioresource Sci., Akita Pref. Univ.)
SATO Fumihiko it Ri Y. ~ (Dept. Agric. Chern. , Kyoto Univ.)
SATO Shinobu it Ri!.], (Inst. BioI. Sci., Tsukuba Univ.)
SUZUKI Kenichi ~i1~(Suntory Ltd.)TSUJIMOTO Hisashi :it /.$:~
(Kihara BioI. Res. Inst. , Yokohama City Univ.)* -Trainees
KOMOMI Yuki

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(Fac. Sci. Tech., Sci. Univ. Tokyo)

Microbial Toxicology Laboratory
Head

YAMAGUCHIIsamu

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ARIE Tsutomu :ff iI
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SOSHI Takayuki ~ JIti ~i 1T

NOSE Yasuhiro

CYCLOTRON CENTER
Chief Scientist
YANO Yasushige
ff 17; I*RIBF Project Office
Head

YANO Yasushige* ff I
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Members
DINH DANG Nguyen
it ~KIM Ka-hae it
KUBO Toshiyuki 0. 1* fi9. ¥MIYASAKA Hiromasa g toc ¥~ iE
YAMAJI Shuhei ilJ lEEr 11~ f

INABE Naohito fiB ill fo1 A
KOHAMA Akihisa IJ\ it i$ :9<:
MADOKORO Hideki Fa' pJT jtj {lijWAKASUGI Masanori ~ if~ ~ i~Visiting Members
ANSARI Ahmad(Inst. Phys., India)
ARAKAWA Kazuo :m}ll *0 X (JAERI, Takasaki Rad. Chern. Res. Estab.)
ARIMA Akito 1r.~ tlfI A (Former President, RIKEN)BANDYOPADHYAY Arup
(Variable Energy CycI. Cen., India)
BAO Jing-Dong(Peking Normal Univ., China)
CHAKRABORTY Tapan(Variable Energy CycI. Cen. , India)
CHATTOPADHYAY Subrata (Variable Energy CycI. Cen. , India)
COLO Gianluca (Univ. Milano, Italy)
EISENMAN Kaury(Michigan State Univ. , USA)
FUJINAWA Tadashi Ri ~~(Mitsubishi Electric Co. , Ltd.)FU JISHIMA Shiro Ri ~ 9:: fm (LH.I.)
FUKUDA Mitsuhiro tM B3 -Jt 1i (JAERI, Takasaki Rad. Chern. Res. Estab.)
HIASA Toshikazu B~)j f*: (Sumitomo Heavy Ind., Ltd.)HIRUMACHI Tamiko ~£IHJ~~-=t- (Toshiba Corp.)
HONMA Toshihiro /.$: Fa' % rt (N.I.R.S.)
KAWAGUCHI Takeo JII 0 it ~ (Mitsubishi Electric Co., Ltd.)KIDO Syuuichi
p 11~ (Hitachi Ltd.)KOSSENKO Grigori(Omsk State Univ., Russia)
KOZU Hideo f$ ~~ jtj:a (Toshiba Corp.)
KUNO Kazuo 0. ff *0 it (Mitsubishi Electric Co., Ltd.)MASUNO Shin-ichi ~ ff ~ (Mitsubishi Electric Co. , Ltd.)*

423

MASUOKA Toshikatu Icl: I1YiJ 1~ 1m (Hitachi Zosen Corp.)
MATSUI Ju-Mei t} it m: SjJ (Mitsubishi Electric Co., Ltd.)MENG Jie(Peking Univ. , China)
MIDORIKAWA Shouichi ~;!J<}l1 ~ (Fac. Eng., Aomori Univ.)
MIRONOV Vladmir(J.I.N.R., Dubna, Russia)
MITSUMOTO Toshinori tIT::$: 1~ $(Sumitomo Heavy Ind., Ltd.)JII ii -tQ
M0 RIKAWA Tetsuya
MOTONAGA Shoushichi 5C 7]<. BB 1::
NAKAZAWA Taro $ ~R~~
OHKAWA Tomohiro 7:.}l1 ~ 7i: (Mitsubishi Res. Inst. Inc.)OHTOMO Kiyotaka 7:. 1£ iN ~f (Sumitomo Heavy Ind. , Ltd.)POLLEY Asis
(Variable Energy Cycl. Cen., India)
SAKURAGI Hiroyuki tf~t. Z(Fac. Sci., Osaka City Univ.)
SEITZ Jeremy(Michigan State Univ., USA)SEKINE Hirotaka ~ fl ~t. ~fSHEN Caiwan(Inst. Theor. Phys. , China)
SIDORIN Anatoly(J.LN.R. , Dubna, Russia)
STOYANOV Chavdar(Sch. Bulg. Acad. Sci. Nucl. Phys., Bulgaria)
TANAKA Yasushi 83 $ 1* it- (Kyokuto Boeki Kaisha, Ltd.)TEZUKA Hirokazu =F ;I:~ i$ (Dept. Liberal Arts, Fac. Literature, Toyo Univ .)THOENNES SEN Michael(Michigan State Univ., USA)TOMINAKA Toshiharu ~ $ ~IJ ¥il (Hitachi Ltd.)UESAKA Tomohiro L t& 1£ i$ (Fac. ScL , Saitama Univ.)
VO Van Thuan(Inst. Nucl. Sci. Tech. , Vietnam Atom. Ener., Vietnam)
ZHOU Shan-Gui(Peking Univ. , China)

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ASANO Tomomasa i~ lH
ff (Fac. Sci., Konan Univ.)
ICHIKAWA Takatoshi
111 ~f fW. (Fac. Sci., Konan Univ.)
OZAWA Shuichi /J~
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GOTO Akira

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FUKUNISHI Nobuhisa t~ [9 ~ roJ
OHNISHI Jun-ichi 7:. [9 *iJ! SAKAMOTO Naruhiko t& 2\( pJG
SUZUKI Naoki ~il
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SATOU Yoshiteru 1t ~ •Visiting Members
CHAKRABARTI Alok
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FUJISAWA Takashi iii rR ~ it (N.I.R.S. )ITOH Yoshiko 1¥
7i' -f- (Adv. Res. Inst. Sci. Eng. , Waseda Univ.)
KIM Jaehong
OKAMURA Hiroyuki I1YiJ ft ~t. Z (Fac. Sci., Saitama Univ.)
SAITO Fuminori 1f iii X fl~
VOROJTSOV Serguei(J.I.N.R., Dubna, Russia)
WEI Long(LH.E.P, China)*

Trainees
KUMASAKA Hirokazu ~~ t& ~t. (Fac. Sci., Saitama Univ.)
MORI Masahiro~ Jt.
(Fac. ScL, Saitama Univ.)
SAKODA Seitaro :iE!rnID&;*~~ (Fac. Sci., Univ. Tokyo)
SATOMI Takehisa ltt J!
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SUZUKI Ryoko jy;
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TAKI Reiko ~~~ r(Pac. Sci., Saitama Univ.)*

Liquid Helium Service Division
Head
YANO Yasushige *- mf $; ~Members
IKEGAMI Kumio

7tf!J:::fL:::: ~OTAKE Masao-)( tT is(a

Beam Technology Division
Head
KASE Masayuki 110 iI ~ Z
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AKIYOSHI Hiromichi f;k E § 7E
FU JIMAKI Masaki Jii ~ lE tit
FUJITA Jiro Jii EEl
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TANABE Toshiya EEl ill fii.9: i:!1
YONEDA Akira
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FUJITA ShinJii EEl*Jf
IKEZAWA Eiji ¥t!! iR
KAGEYAMA Tadashi ~ LlJ
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KIMURA Kazuie
tt MASUDA Akiko irl: EEl ~NAGASE Makoto ffi: iI
IDiX:
OGIWARA Kiyoshi ~)Jj(
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USHIDA Kiminori :It EEl 0 m

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ABE Yasuhisa ~ar:g:~:m 0. (Yukawa Inst. Theor. Phys., Kyoto Univ.)~(NASDA)ABURAYA Takashi im ~ALEXANDROV Vladmir(J.I.N.R., Dubna, Russia)
11~(NASDA)ANZAWA Osamu $; iR
PJ ~~ (NASDA)
AOKI Jiro W
AOYAMA Kazuhiro ' W LlJ
Jt (NASDA)# 11~ :Ie. (Grad. Sch. Inf., Kyoto Univ.)
ARAI Nobuaki
ARITOMO Yoshihiro ~ 1ft:.. & i~ (J.I.N.R., Dubna, Russia)
BABA Shinji .~ jJJi 1;3 ~ (NASDA)
BANERJEE Vaishali(Variable Energy Cycl. Cen. , India)
BHATTACHARYA Sudeb(Saha Inst. Nucl. Phys., India)
BHATTACHARYA Sankar(Variable Energy Cycl. Cen., India)
CHEVTSOV Vladmir(J.I.N.R., Dubna, Russia)
CHIBA Toshiya -T jj€ flj ~FUJIOKA Manabu Jii WiJ?if- (Cycl. Radioisot . Cen., Tohoku Univ~+ ~­FUJIWARA Ichiro Jii)Jj( - ~~ (Dept. Economy, Otemon Gakuin Univ.)
FURUSE Kaoru il 7~
I! (NASDA)
FUTAMI Yasuyuki~
Z (N.I.R.S.)
GOKA Tateo 1i~ ~(NASDA)
HARADA Toru )Jj( EEl~~(Pac. Soc. Inf., Sapporo Gakuin Univ.)¥E (Fac. Sci. , Tohoku Univ.)
HASHIMOTO Osamu tt
HATANAKA Kichiji iII! J:jJ E ¥E (RCNP, Osaka Univ.)(JAERI, Tokai Res. Estab.)
HATSUKAWA Yuichi fJJ)l1
HATTORI Toshiyuki ~Ii:g:~ 13e ¥(Res. Lab. Nucl. React., T.I.T.)
HAYANO Ryugo, S. !f. mf Ii~ 1i (Pac. Sci., Univ. Tokyo)
HEMMI Masatake ~ ~ is(
HIEDA Kohtaro lWf*t:7t*~~ (ColI. Sci., Rikkyo Univ.)

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m

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a-

m:

425

HIROSE Takayuki Jt. 1W~ q:. ¥(NASDA)HIROTA Teruo /J{ EB ~'f ~ (Yanagawa Engineering Co., Ltd.)HONMA Michio
Fa' ~ til (Cen. Mathe. Sci., Univ. Aizu)
HORIBATA Takatoshi ifttl!fffij q:. 1~ (Fac. Eng. , Aomori Univ.)
HORIUCHI Hisashi ifttl P'J
m! (Grad. Sch. Sci., Kyoto Univ.)
HYODO Toshio :% ~Ji 1~ ~ (Grad. Sch. Arts Sci., Univ. Tokyo)
ICHIMURA Munetake rTf ft
lEt (Fac. Gomput. & Inf., Hosei Univ.)
IDESAWA Masanori tB i~ lE fIB (Univ. Electro-Commun.)no Seiji iii f=§ a1f(Sumitomo Heavy Ind., Ltd.)IKEDA Akitsu ?Ii! EB f* if (Shizuoka Inst. Sci. & Tech.)
IKEZOE Hiroshi ?Ii!?~
tt (JAERI, Tokai Res. Estab.)
ISHIZUKA Takeo E ±~ lEt ~ (Fac. Sci. , Saitama Univ.)
ITO Yasuo if!" Wi~(Atomic Energy Res. Cen., Univ. Tokyo)
ITOH Kazuya if!" Wi :to -tf1 (Tandem Accel. Cen., Univ. Tsukuba)
IWAI Satoshi :E:J:t.
fW. (Nuclear Development Co., Ltd.)BE (JAERI, Tokai Res. Estab.)
IWAMOTO Akira :E
IWATA Ren :E EB
wi (Cycl. Radioisot. Cen., Tohoku Univ.)
JEONG S. C.
(High Energy Accel. Res. Organization)(Fac. Sci., Kyushu Univ.)
KAMIMURA Masayasu 1::. ft lE
KANAMORI Takashi ~ ~(NASDA)KATAYAMA Ichiro h LlJ - ~~ (High Energy Accel. Res. Organization)
KATO Kiyoshi ti~ Wi ~ 7i (Fac. Sci., Hokkaido Univ.)
KATSURAGAWA Hidetsugu ;ft 111
ffii~(Fac. Sci., Toho Univ.)
KAWAI Jyun illT -'fri~(Grad. Sch. Eng., Kyoto Univ.)
KAWAZU Akira illT if~(Techno Riken Co. , Ltd.)KOBAYASHI Takao IJ\ iff i%5 ~ (Sansho Setsubi Corp.)
KOMIYAMA Misaki J6 LlJ ~ ~KUBOYAMA Satoshi )\i*LlJ~PJ (NASDA)
KUDO Hisaaki I ~ iA. BE (Fac. Sci. , Niigata Univ.)
KUMADA Masayuki ~~ B3 !1t Z (N.I.R.S.)~(High Energy Accel. Res. Organization)
KURIHARA Toshikazu ~LEE San-mut§ Dt (Inst. Phys., Univ. Tsukuba)
LU Hongfeng(Peking Univ. , China)
MAKIHARA Akiko t~,*~ff.2.r (NASDA)
MATSUDA Sumio l~ EB *tt!. ~ (NASDA)
MATSUNAMI Noriaki 1~ i~ ff.2. 13)j (Sch. Eng. Nagoya Univ.)(Yuuai Corp.)
MATSUO Junko tl ~ *tt!.
MATSUSE Takehiro tl 71 J: 1~ (Fac. Textile Sci. Tech., Shinshu Univ.)
MATSUYANAGI Kenichi 1~ 1'gp liJf (Grad. Sch. Sci. , Kyoto Univ.)
MATSUZAKI Masayuki tl U1~ t!§ Z(Fac. Ed., Fukuoka Univ. Ed.)
MECHTCHERIAKOV Nikolai(Inst. Theor. Eng. Phys., Russia)
MELIN Gerard(Service Ions, Atoms Agregate, CEA, France)
MINAMISONO Tadanori ifj III I~' ~Ij (Grad. Sch. Sci., Osaka Univ.)-tf1 (High Energy Accel. Res. Organization)
MIYATAKE Hiroari '8 lEt
MIYAZAWA Yoshitoshi '8 rR it ~MIZUSAKI Takahiro 7](!iI~ i%5 ¥~ (Fac. Sci., Univ. Tokyo)
MURAKAMI Tetsuya t1" 1::. ~ 1ft (Grad. Sch. Sci. , Kyoto Univ.)
MUTA Atsushi .¢ EB
j!if. (Inst. Phys., Univ. Tsukuba)
MUTO Kazuo lEt ~ - til (Fac. Sci. , T.I.T.)
NAGAI Yuki 71<.:J:t. EI3 *2. (NASDA)
NAGASHIMA Yasuyuki ft ~~Z (Grad. Sch. Arts Sci. , Univ. Tokyo)
NAKADA Hitoshi 9=J EB
1= (Fac. Sci, Chiba Univ.)
NAKAMURA Takashi 9=J tt fi6 ~ (Cycl. Radioisot. Cen., Tohoku Univ.)
NAKAO Noriaki 9=J ~ fIB ~ (High Energy Accel. Res. Organization)
NEMOTO Norio tl
m. ~ (NASDA)
NOMURA Toru It t1"-7 (High Energy Accel. Res. Organization)
NOZAKI Tadashi It U1~
lE (Purex Co.)

*

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*

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*

r

*

*

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426

OGANESSIAN Yuri
(J.I.N.R. , Dubna, Russia)
OGAWA Kengo IJ'\]l1 m.g. (Fac. Sci., Chiba Univ.)(NASDA)OHIRA Hideharu -)( ~ 1§
OHTA KiyoshiEB
1N (Fac. Sci. , Saitama Univ.)
OHTSUKI Tsutomu -)( ifmfJJ (Lab. Nucl. Sci., Tohoku Univ.)e~ (NASDA)
OHYA Jiro -)(OHZONO Hironobu -)( III r15- Z (NASDA)
ONISHI Naoki -)( 1§ ~ ~ (Fac. Eng., Yamanashi Univ.)
001 Makito -}(#7Jif.2.A (Dept. Phys., Sch. Sci. , Univ. Tokyo)
OOTOMO Hiromitsu -)( 17:. ?$ -Jt (NASDA)
POPOV Anatoli(Univ. Latvia, Latvia)
SAGARA Kenshi *§.&}t ~ (Fac. Sci. , Kyushu Univ.)
SAKAI Hideyuki ?~ # ~ 1"1 (Dept. Phys., Sch. Sci. , Univ. Tokyo)
SATO Ken-ichi 1~ Hi ~ (Dept. Phys., Tohoku ColI. Pharm.)
J! (Mitsubishi Res. Inst. Inc.)
SATO Osamu 1tr: Hi
SEKINE Toshiaki ~ ;fN.1~ ~ (JAERI, Takasaki Rad. Chern. Res. Estab.)
SHIMADA Osamu ~ EBfl~
(N ASDA)SHINDO Hiroyuki *JT Hi r15- Z (NASDA)
SHINOZUKA Tsutomu m~$@(Cycl. Radioisot. Cen., Tohoku Univ.)
SHIRKOV Grigori(J.I.N.R., Dubna, Russia)
SOMEKAWA Shuji t4J: iPJ 1§ 16 (NASDA)§ 1)'- (Fac. Sci., Tokyo Metrop. Univ.)
SUEKI Keisuke~(KEK)
SUGAI Isao ;g #SUGAWARA-TANABE Kazuko EB:ill ~D -T (Otsuma Women's ColI.)
SUGIYAMA Hiroki ;f~ LlJ -)( ~j (NASDA)
lE ~ (Irie Koken Co., Ltd.)SUZUKI Masami j~
SUZUKI Toshio j~
1~ ~(ColI. Hum. Sci., Nihon Univ.)~(Inst. Phys., Univ. Tsukuba)
TAGISHI Yoshihiro EB
TAJIMA Naoki EB ~~ ~ ~j (Fac. Eng. , Fukui Univ.)
TAKADA Norio ~ EB ~!:t (NASDA)
1~ ¥6(Mitsubishi Res. Inst. Inc.)TAKAGI Syunji ~TAKEMASA Tadashi m: i& ¥ ± (Kyoto Univ. Edu.)
TAKIGAWA Noboru ?tg)ll~(Fac. Sci., Tohoku Univ.)
TANABE Kosai EB:ill -1!f. ~ (Fac. Sci., Saitama Univ.)
TANAKA Kazuhiro EB ~ ~D rt (Medical Dept. , Juntendo Univ.)
TOHYAMA Mitsuru Ji LlJ?PfiJ(Kyorin Univ.)
TOMODA Toshiaki 17:. EB fit ~ (Fac. Eng., Aomori Univ.)
TOYOKAWA Hiroyuki 1l JII "5t. Z (Electrotechnical Lab. , Agency Ind. Sci. Tech.)
TSUBAKI Noriyuki fi~Ij $(NASDA)
UEHARA Takashi L
Ji (Nuclear Development Co., Ltd.)URITANI Akira JJl ~~(Dept. Phys. , Grad. Sch. Sci., Nagoya Univ.)
UTSUNOMIYA Hiroaki *t~g"5t.~ (Fac. Sci. , Konan Univ.)
VUONG Kim-Au(Inst. Physics-Hanoi-Vietnam, Vietnam)
WADA Ryoichi ~D EB .& (Texas A&M Univ. , USA)
WADA Takahiro ~D EB ~.t(Fac. Sci. , Konan Univ.)
WAKAI Masamiti ~ # JE ill (Grad. Sch. Sci., Osaka Univ.)
YABANA Kazuhiro
115- (Fac. Sci. , Niigata Univ.)
YAMAKI Tsutomu }\ ~~YAMAZAKI Hirohito LlJ /IJ~ ~ f= (Lab. Nucl. Sci., Tohoku Univ.)
YOKOYAMA Ichiro li LlJ - e~
YOSHIDA Nobuaki B'" EB '§> ~ (Fac. Inf. , Kansai Univ.)
YOSHINAGA Naotaka B'" 71<. raJ -1!f. (Fac. Sci., Saitama Univ.)
YOSHIOKA Yasuhiro B'" [iliJ '*"5t. (NASDA)ZHAO Yuliang(Fac. Sci., Tokyo Metrop. Univ.)
ZHAO Yu Min(South East Univ., China)

*

*

*-

*

**

*** *
*

'*

*

*-:rr. -427

Trainees
FUJIMOTO Rintaro ~/.$:***~~ (Dept. Phys. , Sch. Sci., Univ. Tokyo)
HARUYAMA Seigo
WilE:g. (Dept. Phys., Sch. Sci., Univ. Tokyo)
HIGURASHI Yoshihide B ~ ~$ 1!f (ColI. Sci. , Rikkyo Univ.)
IWASE Hiroshi E iii
rt (Fac. Sci., Tohoku Univ.)
KOSHIMIZU Masanori ~ 7.K lE $(Dept. Eng., Grad. Sch. Eng., Univ. Tokyo)
KURITA Tetsuro ~ EEl tg- ~~ (Inst. Phys., Univ. Tsukuba)
MAKIHARA Yasuhiro ~}](
1ft (Dept. Phys., Grad. Sch. Sci. , Nagoya Univ.)
NISHIKAWA Jun 1!9}11;f.tt! (Fac. Sci., Saitama Univ.)
NUNOMIYA Tomoya /ffJ g ~ -ill. (Fac. Sci., Tohoku Univ.)
SASAKI Michiya 16":4*J1i!-ill. (Grad. Sch. Sci., Tohoku Univ.)
SATO Hisaki 16": ~ % it (Fac. Eng. , Tohoku Univ.)
SHIOMI Tomoyuki ~~~ J!
(Fac. Eng., Tohoku Univ.)
SUDA Kenji ~Ji: 83 ~ Iffi~ (Fac. Sci., Saitama Univ.)
TSURUTA Kaoru ~ EEl•(Interdisciplinary Grad. Sch. Eng. Sci. , Kyushu Univ.)
UMEBAYASHI Tsutomu t~
1JJJJ(Dept. Eng. , Grad. Sch. Eng., Univ. Tokyo)
YAGITA Takanori )\*EEI-.$ (Interdisciplinary Grad. Sch. Eng. Sci. , Kyushu Univ.)
YAMAMOTO Sumiko W /.$: *ItJ: -=f (Fac. Sci., Toho Univ.)
YASHIMA Hiroshi }\ lil5
¥15(Fac. Eng., Tohoku Univ.)

*

"*

*;t;

**

Radioisotope Technology Division
Head
YATAGAI Fumio ~EEl~Jt:;K*-

Members
ENOMOTO Shuichi ti /.$:YAN AG IYA Takahiro f~P ~ ~1 7.i
HIRUNUMA Rieko !l!ImtlJiI-=f

OZAKI Takuo ~ IIJ~ !j[ ~~TAMANO Haruna ~ ~J¥j*Visiting Members
GORDON Alasdair
KAGAWA Yasuhiro W )11¥15- (Toray Res. Cen. Inc.)
PJ
KATO Takesi 110 ~KAWAMURA Yoshihiro )II *1" ~ Jr
MAEZAWA Hiroshi lW
tf!i: (Fac. Med. Technol., Univ. Tokushima)
MORIMOTO Shigeko ~ /.$: a-=f
OGURA Koichi IJ'\ ~ *iL (ColI. Ind. Technol. , Nihon Univ.)
YAN G Yongfeng ~71< iii!
AMANO Ryohei X ~ '&.!f (Fac. Med., Kanazawa Univ.)
HIMENO Seiichiro ~llffm:-~~ (Sch. Pharm. Sci., Kitasato Univ.)
INAGE Hiroko frB =B Jr(Showa Women's Univ.)
MATSUMOTO Ken-ichiro ifJ}/.$:~-~~ (Showa Pharmaceutical Univ.)
MINAI Yoshitaka ~ ~ it "if:. (Cen. Art . Sci., Musashi Univ.)
MINAMI Takeshi(Dept. Living Sci., Kinki Univ., Toyooka Jr. ColI.)
NABEKURA Tomohiro J~ ~ ~~.L. (Fac. Pharm. Sci. , Kinki Univ.)
NAKANISI Tomoko I=jJ 1!9 B:.
(Univ. Tokyo)
NAKANISHI Yukiko 9='@Ei:r*-=f (Showa Women's Univ.)
OGURA Yasumitsu IJ'\;fJit
7t (Fac. Pharm. Sci. , Chiba Univ.)
SAKURAI Hiromu ftc #~.L.
(Kyoto Pharmaceutical U niv.)
SHIBATA Sadao #!!§ EEl ~ ~ (N atl. Inst. Radiol. Sci.)
SHINOHARA Atsushi ~}](
IT¥. (Osaka Univ.)
SUZUKI Hiroyuki ~fi~.L. iT(RI Res. Cen. , Chiba Univ.)
SUZUKI Kazuo ~fi
fD ~ (Fac. Pharm. Sci. , Chiba Univ.)
TAGAMI Keiko EEl 1::. ~ -=f (Natl. Inst. Radiol. Sci.)
TAKAHASHI Masaaki ~:.m lE BE (ColI. Agric. , Osaka Pref. Univ.)
TAKAHASHI Yoshio ~:.m~(Fac. Sci., Hiroshima Univ.)

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428

TAKEDA Atsushi lR: EI3 ~ R] (Sch. Pharm. Sci., Shizuoka Univ.)
UCHIDA Shigeo I*J B3 irt::K (Natl. Inst. Radiol. Sci.)
YAMASAKI Mineo LlJ IIJ~ ili!::K (Nara Med. Univ.)
YANAGA Makoto
71<. [lit A (Fac. Sci., Shizuoka Univ.)YASUI Hiroyuki !fi # tft Z (Kyoto Pharmaceutical Univ.)*-

Trainees
INOUE Kensuke it 1: ~ 11'- (Fac. Sci. Eng., Waseda Univ.)
KITO Masatoshi .7l ~j J§ flj (Fac. Sci. Eng. , Waseda Univ.)
KUROBE Toshihiro !!fA:g:B flj tt (Fac. Sci. Eng., Waseda Univ.)•(Fac. Sci. Eng., Waseda Univ.)
OKA Toshitaka [tliJ
GOTO Sachiko 1~Hi1tr:~-=f (Fac. Pharm. Sci., Nagasaki Univ.)
FUGONO Jun ~ If
*It! (Kyoto Pharmaceutical Univ.)
FURUKAWA Jun il JII*It! (Univ. Tokyo)
IGARASHI Kaori 1i.+it~~ (Showa Women's Univ.)
KANAYAMA Yousuke :ili: LlJ i$ 11'- (Fac. Med., Kanazawa Univ.)
MAETSU Hitomi 1W if 1= ~ (Fac. Sci., Shizuoka Univ.)
NAKAYAMA Akihiro q:t LlJ ~ ~t. (Kyoto Pharmaceutical Univ.)
OHYAMA Takuya
LlJ to ttt (Fac. Sci., Shizuoka Univ.)
OIDA Takashi 5.tB3~1Jo5l: (Fac. Sci., Shizuoka Univ.)
SHIOBARA Yamato ij[ JJi(
fO (Fac. Pharm. Sci. , Chiba Univ.)
TSUJI Takae it~ 11(Fac. Med., Kanazawa Univ.)
YOSHIDA Shozo ~ B3 BE = (Nara Med. Univ.)
YOSHIDA Tsutomu "f]" EI3
M (Fac. Sci., Shizuoka Univ.)

*

*

*

ADVANCED ENGINEERING CENTER
Research Instruments Development Division
Head
SENOO Katsumi tl* ~ R C
Members
IKEGAMI Yuji ?tl! 1: ;f,t R]
NOMIYA Yoshio If '8 7f 41
SHIMODA Susumu ~ EI3:i1t
SU G AHARA Seigo 1f JJi( lE 1Ir
URAl Teruo ii # *l ::K
YAMADA Shogo LlJ B3 lE 1Ir

KITSUNAI Tokuji f~ I*J ~ PJ
SHIGA Tsunenobu it- ~ 1t 1§"
SHIRAISHI Akira B 15~
TAJIMA Norio EI3 ~ $ ::K
WATANABE Tokuji i~ ill1.t ?is
YAMADA Yutaka LlJ EI3~Contracting Members
KANEKO Naoe :ili: -=f ~ ~KUBO Ushizo ~ f* :tt Ii
MATSUMOTO Akira 1J}
BE
NIIOKA Yuzo *JT [tliJ ~SASAMOTO Tetsuji tit~ PJ
TAKAHASHI Kiyoji r%J ift it
TOKIWA Saburo 1t ~ =: fm
YAMAMOTO Sumio LlJ
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Surface Characterization Division
Head
IWAKI Masaya :5lE ~*Members
NAKAO Aikoq:t ~ ~ -=f

WATANABE Kowashi

iJi ill

IM]IJ

429

IJ'\

KOBAYASHI Tomohiro

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ADVANCED COMPUTING CENTER
Computational Science Division
Head

EBISUZAKI Toshikazu

fJt 1lI~ 1~ -Members~ ~ fi9. :Yt

IITAKA Toshiaki

Image Information Division
Head

SHIMIZU Hirohiko

7. *- 1ft ~Members

OTANI Chiko -)( t:l- ~D 1T
OKU Takayuki ~~i Z
WATAN ABE Hiroshi iJi ill
tf
KAWASAKI Yoshiya )II 1lI~ it iQ

SATO Hiromi itc ni rt i4ii:
TAKIZAWA Yoshiyuki ~ i' )jt Z
MIYASAKA Hiromasa §:t& i~ iE
ADACHI Tomohiro 17: jl ~*-Visiting Members

KURAKADO Masahiko
SAKAI Kenji i@ # 'OO!

~ r~ ~ ~=BIOGENIC RESOURCES CENTER
Experimental Animal Research Division
Head

KUSAKABE Moriaki

B Tt1~~BB

Members

HIRAIWA Noriko if:E ~ T
IKE Fumio nt!.
fl~ ~KOJIMA Masayo IJ'\ 1fib ~ it
YOSHIDA-NORO Chikako fl'g~1JDTTSUKADA Teruyo j~ rn ::i it
YAMANOUCHI Jyun illzl*J ff
Visiting Members

YODA Yoshika

1t{ rn it W (Japan Sci. Technol. Corp.)

RIKEN BNL Research Center
Head

LEE Tsung-Dao*l
SAMIOS Nicholas P. *2*1 Director, *2 Deputy Director
Experimental
Group Leader

ISHIHARA Masayasu

430D)Jj{ IE ~m

HU JIWARA Kyoko ni)Jj{
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KOGISO Aya IJ'\*~ *3
KUBOTA Yukihiko 'l\f*rn¥~
POIRIER Christophe
YAMAGUCHI Hirotake ill 0 ~L. ~YOSHIKI Atsushi E
i!J:*Deputy Group Leader
BUNCE Gerry M.
Members
BAZILEVSKY Alexander
ICHIHARA Takashi
JJi(!j[
SAITO Naohito ~ ii ~ A
KURITA Kazuyoshi ~ EB to ~tmVisiting Members
JACAK Barbara V.
KOBAYASHI Hideyuki

Ij,

DESHPANDE Abhay
WATANABE Yasushi iJi jf:
GOTO Yuji 1& ii
GROSS PERDEKAMP Matthiasa='*** * ¥

TheoryGroup Leader
LEE Tsung-Dao
Deputy Group Leader
BALTZ Anthony J.

*

Members
AOKI Yasumichi W 1* ~BOER Daniel
NARA Yasushi
RISCHKE Dirk-Hermann
VOGELSANG Werner*.&

BLUM Thomas C.
ITAKURA Kazunori t~ ~ ~ ~[.
ORIGINOS Konstantinos N.
SCHAFFNER-BIELICH Jurgen

Visiting Members
BASS Steffen A.
(Duke Univ. , USA)BODEKER Dietrich(Niels Bohr Inst. , Denmark)
GYULASSY Miklos(Columbia Univ. , USA)
JAFFE Robert L.
(Massachusetts Inst. Technol., USA)
KUSENKO Alexander(Univ. California, Los Angels, USA)
MAWHINNEY Robert(Columbia Univ., USA)OHTA Shigemi
EB i~ ~ (KEK)
SCHAEFER Thomas(State Univ. New York, Stony Brook, USA)SHURYAK Edward V.
(State Univ. New York, Stony Brook, USA)SON Dam Thanh(Columbia Univ., USA)
(Univ. Illinois, Chicago, USA)
STEPHANOV Mikhail A.
VENUGOPALAN Rajagopal
WETTIG Tilo
(Yale Univ., USA)van KOLCK Ubirajara(Arizona Univ. , USA)"*

Administration
ESPOSITO Pamela
GREENBERG Rae
HEINZ Tammy Anne
ITO Taeko W iii ~j -=fAdministrative Manager
NODA Toshihito mt EB ~ A
Deputy Administrative Manager
HaRlE Hironori #ill
tYf :f;rI

431

International Frontier Research Group on Earthquakes
Members
WATANABE Hiroshi iii ill.
tf

Safety Center
Members
FUKAZAWA Kunio 1* 1R 00
KAGAYA Satoru 1JDJi~ 'I'!
MIYAGAWA Makoto g }II ~ j§
SHINOHARA Shigemi ~G
YOSHIKI Hajime E ~
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m: a

432

m:

HARASAWA Kaoru
7R •KOBAYASHI Hiroshi IJ,
tf
SHIMAGAKI Masayuki ~~ m IE ZUWAMINO Yoshitomo J:~~~)j*

AUTHOR INDEXABE Ryo~PJ$~

BOTELHO Suzanna

5261

ABE Tomoko~PJ:g:~~T

167, 168, 169, 171, 172

BOYD Richard N.

55

ABE Yasuhisa~iiJ:g:~~~36, 37

BREHMER Sven

121

ADACHI Takashi

JtJi: ~ 117
AIHARA Toshimitsu ~,*flJ:7t 3,324

BROOKS Melynda L. 237, 244
BROWN B. Alex 15,17

AKAGI Hiroyasu $*** 5
AKAISHI Yoshinori ${:i ~*,2. 40

BROWN David S.

229, 234, 237

BRUNER Nichelle

237

AKIBA Yasuyuki ~jdfU1tz 240, 259
AKIYOSHI Hiromichi fj(::g§JE 65, 75, 193, 315

BUCURESCU Dorel 56,206
BUENKER Robert J. 79
BUNCE Gerry 227,229,234,236,240

AKOSHIMA Megumi ~PJ-=f~~ <"hALEKSEEV Igor 229, 234, 236 '117

CEDERWALL Bo

56,206AMANO Ryohei::Rmt N..!f 132, 134, 136, 147

CHAKRABARTI Alok

AMBE Fumitoshi*:g:~JtfVk

CHELNOKOV Maxim 1.

ANDO Kozo

94, 96, 125*niIMJ1J:::: 105

ANDO Yoshiaki *ni&~
ANSARI Ahmad 31,32
~

li#

73,75

CHIBA Masami

f-~:/~7E

63, 179, 209

CHIBA Toshiya

f-~fIJ~

303, 305, 315, 316, 322

264

CHIBA Yoshiakif-~HI3J:1

322,355,364

CHIMI Yasuhiro~~JjJt~~90, 91, 93

W*1;Jfh~

AOKI Yasumichi

61

278

65, 73, 75, 206

ANSELMINO Mauro
AOI Nori

CHEN Dong

74

273

AOKI Yuka li*EI3w 58
AOYAMA Masashi liUJ~1t!:

117

CHRIST Norman 278
CHU J 0 Tatsuya 9=t 1,*Jt ttL 260
CIANCIOLO Vince 230,240,242

ARIE Tsutomu::ffrI 1J

165

CRUCERU Ilie

63

ARIMA Akito:ff.~i!nA

13, 19, 20, 25, 26, 28, 30, 31,

CSATLOS M.

67

32

ASAHI Koichiro

1I!!

66, 68, 70, 157, 181, 190,

CSIZMADIA Peter 286
D'ALESIO Umberto 264

200, 208, 214, 215

DAVID Gabor

ASAMI Tadao~~~.[l,~fjj: - i!~

232, 238, 261

DEMICHI Kimihikolliit1=~AZUMA Toshiyuki~~T 88
BAcK Torbj6rn 56, 206
BABA Hidetada .~~~,[l, 65, 67, 73, 75, 221

DESHPANDE Abhay

229, 234, 236, 251

BAI Mei 236
BAIER Rudolf 290

DINH DANG Nguyen ~~~DOKE Tadayoshi it*,[l,tt;

171

"*

BANDYOPADHYAY Arup
BANERJEE Vaishali
BAO Jing-Dong

74

DIAO Xungang?J

DOMBRADI ZS.

~JIIIMJIJ

94, 96, 98, 99, 100

236

BAZILEVSKY Alexander

232, 238, 243

BEAUMEL Didier

74

BENTZ Wolfgang

26, 274

BHATTACHARJEE Sudeep309

13, 28, 29, 30, 31, 32

204
272

236

DUMITRIU Dana

106, 114

DUTTA Chizuko M.

79

EADES John

~JC

67

DOSKOW Jack240

BASSALLECK Bernd

229,234

DONG Yu-Bing ii *~DONG Zhihua 278

74

36

BARISH Kenneth

DHAWAN Satish

73

123

EATON Gordon H. 46, 47
ECCLESTON Roger S. 121

BICK Michael

240

EGAWA ChierIJI I ?§l*~

BLUM Thomas

277,280

EILERTS Scott

236

EN'YO Hideto~W-~A

229,230,232,234,238,244,

ENDO Atsumi

Jini~~

116

BOER Daniel

249,264

BOGDANOV Dmitrii D.
BOILLEY David36

BORDEANU Cristina 63

61

153

252, 254, 256, 258

ENDO Kazutoyo

Jinifo.:!: 130

tl*~-ENOMOTO Shuichi

FULOP Zsolt

126, 127, 128, 129, 130,

243, 244, 248, 252, 254, 256,

131, 132, 134, 136, 137,

258

139, 140, 141, 143, 145,

GROSSE PERDEKAMP Matthias

147, 148, 150, 151, 153,

GU Jiang-Pin

155, 157

GULyAS J.

83

FAMIANO Michael

55

FIELDS Douglas E.

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132, 134, 136~i',*1~

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236

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LILLIE Benjamin
LIU X.

240

67
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LOZOWSKI William
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175, 176
91

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75

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65, 67, 73, 75, 183

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77

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MADOKORO Hideki ra~PJT*~f 22, 24
MAEDA Kuniko lW83j:5r 224
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101
130

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MCLERRAN Larry

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22

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MICHIKAMI Osamu ~J:.

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119, 162, 212, 297

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339

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MURATA Jiro ft83*e~
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111, 112, 202

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OHTANI Shunsuke*ti-1~1r

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PIERROUTSAKOU Dimitra

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103

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PRATT Francis L.

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PRZEWOSKI Barbara V.
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RINKEL Tom

236

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