ISSN 0289-842X

RIKEN
Accelerator
Progress Report
vol.

33

理化学研究所

RIKEN (The Institute of Physical and Chemical Research)

RIKEN Accelerator Progress Report
January-December

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vol. 33

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RIKEN (The Institute of Physical and Chemical Research)
Wako, Saitama, 351-0198 JAPAN.
.'Editors

T. AbeA. GotoT. Ichihara

R. Kadono

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
1The Tandem Operation ..............................................................

3

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

4

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

6

III.

RESEARCH ACTIVITIES

1.

Nuclear Physics

Reaction Mechanism and Characteristics of T 20 in d+ 3 He Backward Elastic
Scattering at Intermediate Energies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

9Structure of Li Isotopes Studied by Gaussian Single-Particle Bases ........ . ..........

10

Molecular-Orbital Structure in Be Isotopes ............ . .............................

11

Model-Independent Analysis of the One-Body Density of Unstable Nuclei ............

13

Development of a New Code for Large-Scale Shell-Model Calculations Usinga Parallel Computer. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

14

Monte Carlo Shell-Model Study of Unstable Nuclei around N = 20 ...................

15

A Search for a Unified Effective Interaction for Monte Carlo Shell-Model
Calculations .........................................................................

16

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

17

The Nucleon Pair Approximation of the Shell Model. ... .. .. .... .... .... .. ........ .. .

18

Effects of the Dirac Sea on the Giant Monopole States ...............................

19

The Phonon Damping Model........................................................

20

Statistical Analysis of the Hot Giant Dipole Resonance with the Phonon Damping
Model................... . ...........................................................

21

Hot Giant Dipole Resonance in the Static Path Approximation ......................

22

Damping of Multiphonon Giant Resonances .........................................

23

Giant Dipole Resonance in Neutron-Rich Nuclei within the Phonon Damping
Model...............................................................................

24

Local Harmonic Approaches with Approximate Cranking Operators... .. .. . ........ ..

25

Relativistic Tilted Axis Cranking Model and Its Application to Shears Bandsin the A = 80 Mass Region ................... .. . ....................................

26

Wobbling Motion in the Multi-Bands Crossing Region ...............................

27

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

28

The r-Process Nucleosynthesis in Supernovae ........................................

29

Hydrodynamical Study of Neutrino-Driven Winds as r-Process Sites .................

31

.,

1.

.

is

44Ti: Its Effective Decay Rate iri Young Supernova Remnants, and Its Abundancein Cassiopeia A ................................................. . ....................

32

A New Parameterization of Polarized Parton Distribution Functions ......... , ... : ..

I

33

Large PT A! Production in Polarized PP Scattering.' ........ . : . . . . . . . . . . . . . . . . . .. . .. .

34

A: Productions in Polarized ep Reaction and Polarized Gluons in the Proton . '.' . . . . .

35

Behavior of Polarized Light Sea-Quarks in a Nucleon : .......... .. ...............: . ....

36

Color-Octet Contribution to the Photoproduction of 'lj;' ................ : .. ......".. '. . . .

37

Antiquar k Flavor Asymmetry in Polarized Drell-Yan Processes ......... ..... ......

7 • •

3,8

Nucleon-Structure Functions in the NJL Model ..................... . ............. '.. ,39

U A (1) Symmetry Breaking and Eta Prime Meson in the Bethe-Sal peter Approach . ...

40

Final Countdown to RHIC Spin Program ....... . ................... . ................

41

Measurement of the Charged Pion Asymmetry and Beam Polarization in AGS
E925 ......................... ... ... ...... ............ ..... .. ....... ...................

43

Sensitivities of the Gluon Polarization Measurement at PHENIX. . . . . . . . . . . . . . . . . . . . .

44

Performance of the PHENIX Muon Reconstruction Software .........................

46

Precise Measurement of the Muon Lifetime .......................... . .. . ............

48

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

49

Study of Muon Catalyzed Fusion in Solid D-T Mixtures ........................ .....

51

Electron Scattering at MUSES IRIBF ..........:..................... . ................

52

Kr;, d-p

Measurement of the Polarization Transfer Coefficients,
for
EI<;tstic
Scattering at Ed = 270 Me V ...... ............... .................. ..... .............

53

Measurement of the Cross Sections and Vector and Tensor Analyzing Powers
for d- P Elastic Scattering at Ed = 270 Me V ................................. .. ........

54

The 3He (d~ p ) 4He Reaction at Intermediate Energies .............................,' ...

55

J:Measurement of the Deuteron Spin-Flip Probabilities in the 28Si( d') Reactionat Ed = 270 MeV .......... '.................. .... .............. ..... ............ ...... ..

56

Proton Spectra from the 208Pb + 208Pb Reaction at 15 A MeV ...... ........ ... ....

57

GDR ,,-Rays from the Binary Reaction of 209Bi + 209Bi at 12 MeV lu ....... ......... .

58

Search for a Z = 118 Superheavy Nucleus in the Reaction of 84Kr with 208Pb

59

First Measuremep.t of the 8B(p,,,)9C Reaction by the Coulomb-Dissociation
Method .... ~ ................... ~ ................ ................. ; . . . . . . . . . . . . . . . . . .

60

Development of a Li-Ion Isotope Separation and Coun,ting System for a Precise
Measurement of the 11 Li Charge Radius ..... .' ... . ..... ...... : ...... . .................

61

Coulomb Dissociation of 12N and 13 0

63

Coulomb Dissociation of 13N and 14 0

65

Isobaric Analog State of 14Be

66

Coulomb Excitation of 15 0

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67

Coulomb Excitation of 28Ne and 32, 34 Mg . ... ... ... .. .................................

68

Po~ulation of Excited States in Unstable Nuclei Produced by the Fragmentationof 6Si ... . ... .... .... ............................. .............. ............... .'.....

69

Gamma-Ray Spectroscopy of the Very Neutron-Rich Nucleus 34Mg ........... ..... ...

70

Half-Life Determination of 44Ti Using a Radioactive Beam Technique..... .... ..... . .

72

Collective States of Neutron-Deficient Doubly Even Barium Isotopes .................

73

Production Cross Sections of Light Neutron-Rich Nuclei from 40 Ar Fragmentation

74

Atomic and Solid-State Physics
Positron Scattering by Polyatomic Molecules

75

Total Cross Sections for Electron and Positron Collisions with CF31 Molecules .......

76

Simulation of a Diatomic Molecule Colliding with Surfaces ...................... '. . . . .

77

Radiative Electron Capture of Swift Heavy Ions into the Continuum State ... .. ..... . . 78
Fullerene-like Fragment Ion Production in Fast Ion-C 60 Collision ... ........ ..... . ',' . .

79

Isotope Shifts between He-like 12C and 13C Ions ................................ '.....

80

Foil Ageing Problems in Beam-Foil Spectroscopy Continued. . . . . . . . . . . . . . . . . . . . . . . . . .

81

Time Delayed Spectral Lines in Beam-Foil Spectroscopy . ..... . .. .. .... .. ............

82

Spectroscopy of High Z Spin-Aligned States. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

83

High-Resolution Soft X-Ray Study of Ne Hollow Atoms Created by a Microcapillary
Target........................................ .......................................

84

Angular Dependence of Scattering Intensity in C 4+ + He ~ C 2+ + He 2+
at Collisional Energy of 120 eV / q ..................... ................ ...............

85

Acoustic Emission Following Fast Heavy-Ion Irradiation of Solids . ..... .. ,'...........

86

Defect Production via Electronic Excitation in Oxide Superconductors Irradiatedwith High Energy Heavy Ions ........................................................

87

Effects of Defect Morphology on the Vortex Dynamics in Bi2Sr2CaCu208+8
Irradiated with Ge V Heavy Ions .. .. .. ..... . ......................... .. ....... .......

88

Radiation Annealing Induced by Electronic Excitation in Iron . ......................

89

Infrared Spectroscopy Study on Vacancy-Oxygen Pairs in CZ-Si Irradiatedby 3.5 GeV Xe Ions . .............. . ....................................... : .........

90

Evaluation of SEB in Power MOSFETs Caused by Heavy Ions.......................

91

Dynamic Behavior of a Nuclear Probe 57Mn/57Fe in Si after Projectile-Fragment
Separation and Implantation ................................................. : ..... .

93

Atomic-Force-Microscopy Observations of FZ-Si after GeV- 57 Mn Implantation
Using RIKEN Projectile Fragment Separator (RIPS) ........................ ~. ... ....

94

A New Spin Polarimeter Proposed for Spin-Polarized Slow Positron Beams

95

3.

Xe Bubble Formation in Xe-Implanted Fe as Observed by the Channelling Method...

97

Observation of Ion Current in Superfluid Helium. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

99

Observation of a Full Dispersion Curve for the Low Energy Excitation in a Spin
Ladder..............................................................................

100{tSR Study on the 1/8 Effect in the Bi-2212 System ................................ : .

101

LF-{tSR Studies of the Vortex State in Bi2Sr2CaCu20x ..............................

102

Current-Induced Vortex Motion in Type-II Superconductors .........................

103{tSR Study on the Spin Dynamics of Kagome Antiferromagnet, m-MPYNN·BF 4104

Radio-frequency Muon Spin Resonance of a Haldane-Gap System NiC 2 0 4
2·(2-methylimidazole) ................................................................

105

Muon Spin Resonance Study on an Organic Radical TEMPO Derivative.............

106

Intra- and Inter-molecular Electron Transfer in Cytochrome c and Myoglobin
Observed by the Muon Spin Relaxation Method .....................................

107

Radiochemistry and Nuclear Chemistry
In-beam Mossbauer Study of 57Mn/57Fe in Si Following Projectile Fragmentation
and Implantation ....................................................................

109

Biological Transport of the Various Trace Elements in the Pregnant Rats and Fetus ..

111

Uptake of Zinc and Other Trace Metals in Tumor-Bearing Murines ..................

112

Biological Tissue Distribution of Vanadium in STZ-Induced Diabetic Rats:
Simultaneous Tracing of V, Cr, Mn, Fe, Co, Zn, and Se Using a Radioactive
Multitracer ..........................................................................

113

Metabolic Study of Trace Elements in Se-Deficient Rats (IV) ........................

114

Distribution of Bio-Trace Elements in Cell Fraction of Selenium-Deficient Rat Liver

116

Effect of Dietary Selenium Spedes and Doses on the Organ Distribution ofMultitracer ..........................................................................

117

Uptake Rates of Trace Elements in Zn-Deficient Mice...... ...... ... ............ . ....

118

Characterization of Manganese Transport System Using Cadmium-ResistantMetallothionein-Null Cells ................................................ . ..........

119

Biobehavior of Multitracers in the Brain and Other Organs of 1-, 3- and
8-Week-Old Mice...... .. .. ... .. .. ... ............ ......... ... .. ........ ... .. .. . . . ....

120

Effect of Oral Administration of NaFeEDTA on the Biodistribution of Trace
Elements ............................................................................

121

Contribution of Arbuscular Mycorrhizal Hyphae to Acquisition of Trace Elements
by Marigold......... ..... ..... .... ....................................... ....... ....

122

Influence of Zn on the Uptake of Various Elements into Carrot .......................

123

Enhanced Uptake of Mn by LeGlpl- Transgenic Tobacco Plants ......................

125

Selective Detection of EC-Decay Radionuclides in Multitracers: A Proposal ..........

127

Evaluation of the in vitro Stability of Radiolabeled DTPA and DOTA and Their
Conjugated Antibodies ..............................................................

128

4.

5.

HPLC Elution Behavior of Multitracer Metallofullerenes

129

Gamma-Ray Detection Systeln for Multitracer Research

130

Time Course Induction of p53 in Human Cell Lines131

Radiation Chemistry and Radiation Biology
Electron-Hole Plasma Luminescence from the Ion Track of Insulator Crystals

133

Luminescence Spectra and Decay Curves of Diamond Crystals Irradiated by
Heavy Ions ..... .. ... .... ........ ................. ......... ....... ...................

134

Ultrafast Luminescence and Exciton Dynamics in Ion-Irradiated RbI Single Crystal ..

135

Strontium Uptake by Yeast Schizosaccharomyces pombe ..... ............. ............

137

Influence of Endophytes on the Uptake of Radionuclides by Perennial Ryegrass ......

138

Analysis of Heavy-Ion Beam-Induced DNA Damage in Saccharomyces cerevisiae .....

139

Effective Plant-Mutation Method Using Heavy-Ion Beams (IV) ......................

140

Effects of Heavy-Ion Beam Irradiation on Shoot Elongation in Roses ..... ............

141

Adaptive Response of Human Cultured Cells to Heavy-Ion Irradiation ......... ......

142

Cytogenetic Effects of Heavy-Ion Beams on Mammalian Cells. ..... .... .. .. . .. ... . . . .

144

Effect of Heavy Ion Beams on Cell Cycle Progression ...... . .......... ...............

145

Recognition of Hit Sites within the Cells Exposed to Accelerated Iron Ions Using
CR-39 Plastics ...... . .......... ..... ........... . ............. .......................

146

Oxidation Degradation of High Density Polyethylene Irradiated with Ion Beam ......

147

Heavy Ion Beams: Application to Mouse Mutagenesis (II) ...........................

148

Instrumentation
Design of Liquid-He-Free Superconducting Solenoid Coils for Electron Cyclotron
Resonance Ion Source ...............................................................

149

Automatic 18F Supply System for a Slow Positron Beam .............................

151

Design and Simulation of an Electrostatic Spin-Polarized Positron Beam System
for Surface Magnetism Studies ..................................... ..................

152

Calibration of Beam-Line Polarimeter at Ed = 140 and 200 MeV. .. ... . .. .. . . .. .. .. ..

153

Absolute Calibration of the Deuteron Beam Polarization at an Intermediate Energy
via the 12C(d, a) Reaction ............... ........ ..... ... .................. ..... .....

154

Calibration of 3He Polarization Using Electron-Spin-Resonance Method ..............

156

Response of an Imaging Plate for Heavy Particles. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

158

Development of Time-of-Flight Detector with Streak Camera ........................

159

Development of a New Photon Detector System for Nuclide Identification. . . . . . . . . . . .

161

Development of High-Efficiency Delay-Line PPAC for High-Energy Light Ions.. .. ....

163

Construction of PHENIX Muon Tracking Chambers .................................

165

6.

7.

IV.

Status of PHENIX Muon Identifier Mechanics .......................................

166

High-Energy Beam Test of PHENIX EM Calorimeter at CERN. ... .. .. ......... .....

168

Feasibility Test of Proton-Carbon CNI Polarimeter for RHIC .............. . .........

170

PHENIX Computing Center in Japan (CC-J) ............... ... ................... ~ . .

172

A Workstation Farm Optimized for Monte Carlo Shell Model Calculations:
Alphleet .............................. . . .......................... . ...... . ...........

174

Development of High-Rate MUSIC .......... . .......... . ..... ... ....................

176

Calibration of Heavy Ion Telescope on Board MDS-l Satellite with 40 Ar Beam .......

177

Beam Calibration of Fiber Neutron Monitor onboard the Exposed Facility of theJapanese Experimental Module. .. .. .. . . .. . .. ... .... ... . .. . . . ... . . . .. .. . ... .. . .. .....

178

RF Ion-Guide System for Trapping Energetic Radioactive Nuclear Ions from
Fragment Separators ................................................................

180

Development of a Polarized Solid Proton Target by Means of the Integrated Solid
Effect (ISE) .........................................................................

182

Material Analysis
Development of a Highly Sensitive High-Resolution In-Air Particle-Induced
X-Ray Emission (PIXE) System: I ...................................................

183

PIXE Analysis of Lead in the Feather of a Jungle Crow Living in Tokyo .............

185

RBS Analysis of Na-Implanted Glassy Carbon . ......................................

186

Heavy-Ion Irradiation Effects in Bi-2223 Tapes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

187

ANew Method for Determining the Vacancy Formation Energy of Metals
Using the Positron Age-Momentum Correlation Technique ...........................

188

Miscellaneous
Neutrino Advanced Generation with Accelerated Muon

189

Light Hadron Spectrum in Quenched Lattice QCD ...................................

191

Monte Carlo Simulation of Supersymmetric Matrix Model ...........................

192

New Method for Trace Element Analysis Using the Electron Cyclotron ResonanceIon Source and Heavy-Ion Linac ..................................... . ...............

193

NUCLEAR DATA

Status Report of the Nuclear Data Group. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
V.

195

DEVELOPMENT OF ACCELERATOR FACILITIES

Biased Electrode Method for RIKEN 18 GHz ECRIS

197

Present Status of 14.5 GHz Caprice in RIKEN .......................................

199

Development of Compact High Current Multicharged Ion Source for RIKEN RI
Beam Factory .......................................................................

200

Laser-Plasma Production for Laser Ion Source at RIKEN ............................

202

Generation of Heavy-Ion Pulses with Short Width and Long Interval. . . . . . . . . . . . . . . . .

203

A Plan for a New Control System for the RIKEN Ring Cyclotron Using' EPICS ~;....

204"

Low Power Test of CSM Resonators ................ .. ...............................

206

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

208

Model Test of the RIKEN -IRC Main Resonator ......................................

210

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

212

Development and Construction of the SRC Sector Magnets ........ . .............. . ..

214

Quench Analysis of Stagnant Normal Zone in the RIKEN Prototype Sector Magnet. .

216

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

218

Superconducting Magnetic Channel for the RIKEN Superconducting Ring,
Cyclotron ...........................................................................

220

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

222

Design of the RIKEN-SRC RF System...............................................

224

Vacuum System for the RIKEN Superconducting Ring Cyclotron ....................

226

Influence of External Magnetic Field on the Performance of Cold Cathode Gauges ...

228

Design Studies on Beam Transport System of RIKEN RI Beam Factory. ........ . . . ..

230

Design Study of Beam Transport Lines from SRC to Three Big RIPSs ..... ..........

232

Design of a 2 T Room-Temperature Dipole Magnet for Beam Transport Lines
of RIBF Project........... .... .. ...... ... . ......... ....... ....... . .. ... ...... .. . ... .

234

Design of the BigRIPS Separator for the RIKEN RI-Beam Factory Project ..........

236

Design of a Superferric Quadrupole Magnet for the RIKEN RI-Beam Factory
Project .................... ... ....................................... .. ...............

238

Estimation of Deposited Heat and Damage by Neutrons on the Downstream
Superconducting Magnet of the Target Assembly ....................................

241

Shielding Design of RIKEN RI Beam Factory ................ . .......................

243

Refinement of Accumulator Cooler Ring Lattice Design ... . .. ........................

245

Development of ACR Electron Cooler (2) ......... . ..................................

247

Study of Pickup for Stochastic Cooling ..............................................

249

The Ferrite Test Cavity for MUSES (II) .............................................

251

Development of the Kicker Magnet for BSR ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

253

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

255

Preliminary Studies on CORBA-based RIBF Control System ........................

257

Spin Tracking with "Real" Siberian Snakes in Relativistic Heavy Ion
Collider(RHIC) ......................................................................

259

Ion Optics Study of RHIC OPPIS .................... . ....................... . ......

261

Ultraslow Muon Production Using the Resonant Ionization Method.. .. ....... . .. .. ..

263

VI.

RADIATION MONITORING

Radiation Safety Control System for the RIKEN Ring Cyclotron ..... .... ............

265

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

266

VII.

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

269

VIII.

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

276

IX.

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

279

X.

LIST OF SYMPOSIA

292

XI.

LIST OF SEMINARS .. ... ...............................................................

294

XII.

LIST OF PERSONNEL ..................................................................

299

AUTHOR INDEX

I. PREFACE

This issue of RIKEN Accelerator Progress Reportreports research activities of the RIKEN Accelerator
Research .Facility (RARF) during the calendar yearof 1999. The research programs have ,been coordinated in 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 or radiation application, basic studies on energy
production, basic studies on accelerator cancer therapy, material characterization, application to space science, accelerator physics and engineering, laser technology, and computational technology. These activities involved 12 laboratories in RIKEN and more than
300 researchers including outside users from domestic
and foreign institutions. Thirty-six universities andinstitutes from within Japan and 33 institutes from10 countries are included.
Major research activities of the RARF are basedon the heavy-ion accelerator complex consists of theK = 540 MeV RIKEN Ring Cyclotron (RRC) , theenergy-variable heavy-ion linear accelerator (RILAC)
and the K = 70 Me V azimuthally variable field cyclotron (AVF), which have altogether provided a beamtime (on the target) of more than 6500 hours throughthe year. The operation time is shorter than those of1998 because of the two and half months shutdown due
to the part of the construction-program of RI Beam
Factory.
The three accelerators deliver heavy-ion beams of avariety of elements with energies ranging from a few A
MeV to 135 A 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(5 A MeV) beam of 54Kr has been accelerated for the
study of superheavy elements. The beam current ashigh as 0.8 particle pA was delivered on the target.
Two new laboratories have been established. One isApplied Nuclear Physics Laboratory and the other is
Beam Dynamics Laboratory. The later is the laboratory that takes care of the construction of MUSES in

RI Beam Factory.
Two third of the RRC research beam time
( rv 5000 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.
The use of radioactive-ion (RI) beams cis" the .mainemphasis of the science at the RRC. Three different
types of radioactive beams, i.e., (1) projectile-fragment(PF) radioactive beam, (2) spin-polarized radioactive
beam, and (3) high-spin isomer beam, have been developed and used in a broad scope of nuclear research.
The PF beams are most widely used by virtue of
their versatility and prominent intensities. The spinpolarized beams are particularly useful for NMR experiments of radioactive isotopes. These beams areprimarily used for the study of nuclear physics. Major
subjects pursued are: (1) exotic nuclear structure andnew dynamics of extremely neutron-rich nuclei (suchas those with a neutron halo or skin), (2) nuclear astrophysics involving unstable-nucleus reactions, (3) synthesis of new unstable isotopes far from the valley ofstability, (4) extensive measurements of nuclear moments. Characteristic features of intermediate-energy
direct reactions are often exploited for such studies.
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
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.
Another remarkable development has been seen in
the application field of radioactive tracer technique.
High-energy heavy ion reactions facilitate productionof a wide variety of isotopes simultaneously. Thisfeature is exploited to cultivate a novel multi-tracer
methodology in which a radioactive tracer source con-

taining a variety of elements is prepared to be injected
into a sample. This enabled to study circulation behaviors of different elements for a common sample,
drastically improving reliability and efficiency over the
single-tracer experiments. Application of the method
is rapidly extending to the fields of bioinorganic chemistry, dietetics, toxicology, pharmacology, environmental issues, and medical fields in general.
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 incollaboration with the Ratherford-Appleton Laboratory (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. Studies of quarkgluon spin structure functions at BNL/RHIC are waiting for the commissioning of RHIC operation soon.
The RIKEN /BNL Research Center is in operation andattracts physicists from all over the world. The large
computer system for the analysis (CC-J) is under construction.
The RI beam factory project is going reasonably
fast. The construction of the sector magnet for thebooster cyclotron (ISR) has been completed and magnetic field measurements are in progress. Windings ofthe superconducting coil for the ring cyclotron (SRC,
K = 2500 MeV) is also in progress. The design workof MUSES (accumulator ring and colliding rings) has
been started.

1. Tanihata
Director
RIKEN Accelerator Research Facility

2

II.

OPERATION OF ACCELERATORSRIKEN Accel. Prog. Rep. 33 (2000)

The Tandem Operation
K. Ogiwara, E. Yagi , and T. Urai
The 1.7 MV tandem accelerator has been moved toa new experimentation hall, following the construction plan of the new accelerator facilities (RIBF) , and,
therefore, was shut down from March to the end of
August , 1999. It was, however, operated for 40 daysfor experiments, except for the machine inspection andbeam test, during the annual reporting period from
Nov. 1, 1998 to Oct. 31 , 1999.
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 II-VI compound semiconductors.
(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
using the channelling method.
(3) Particle-Induced X-ray Emission (PIXE)(a) Application of PIXE in the biomedical and materials sciences: Trace element analysis using energydispersive 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 II-VI ternary semiconducting crystals.

3

RI K EN A eeei. Prog. Rep. 33 (2000)

RRC and AVF Cyclotron Operations
M. Kase , A. Goto, T . Kageyama, M. Nagase, S. Kohara, T. Nakagawa, K. Ikegami, J. Fujita, N. Inabe,
O. Kamigaito , M. Kidera, M. Komiyama, A. Yoneda, 1. Yokoyama, H. Isshiki,* H. Akagi,* R. Abe,*N. Tsukiori,* K. Takahashi,* T. Maie ,* T. Homma,* R. Ohta,* K. Kobayashi,* and Y. Yano
The operation statistics of the RIKEN Ring Cyclotron (RRC) for 1999 are listed in Table 1. The
cumulative statistics since the beginning of operationin 1986 are shown in Fig. 1.
The total hours of operation in 1999 amounted to5060 hr. This is 20% less than that in the previous
year. The main reason for this decrease is the shutdown of all machines for two months due to the preparation for the RI Beam Factory (RIBF) project.
In order to clear the construction site for the new
RIBF .buildings, every power station, heat source andwater supply for all the existing machines was moved to
the west side of the Nishina Memorial Building. New

buildings for RF power supplies for RRC and RILAC
were constructed on the south and north sides of the
Nishina Memorial Building, respectively. Almost all
cables and pipes connecting the machines to these facilities outside of the building were replaced. The renovation began in February and was finished completely
in the middle of April.
The lower limit of output energy ' of RRC ,which had been 7 MeV/nucleon, was decreased to
5.5 MeV/nucleon using a harmonic number of 13. A
5.5 MeV/nucleon 84Kr beam was successfully accelerated with an intensity of 1 pJ.LA in September 1999.
The parameters are listed in Table 2. This' beam
was required in the research of superheavy elements(Z = 118) . The experiment in the GAs-filled Recoil
Isotope Separator (GARIS) was carried out in Octoberusing this beam for a duration of as long as two weeks.
The operation with a harmonics of 13 is extremely
inefficient, especially in RILAC. Only first three cavities of RILAC are operated with very low power levels.
To make the acceleration of a low energy beam more efficient , RILAC energy will be upgraded by using acceleration cavities of Charge State Multiplier (CSM). The
maximum energy will be 6 Mev/nucleon, which meetsthe requirements of superheavy elements research.
Six CSM cavities will be installed just after RILAC.

Table 1. Statistics of RRC Operation .
Category
Total of Operatiion Time
(Beam Tuning)(Nucl. Phys. Experiments)(Other Field Experiments)
Trouble Shooting
Open House for Guests
Construction
Holiday & Maintenacnee
Total

Hours
5060

1400
2980
680

460
40
1700
1500
8760
Construction Time

ConstructionTime
Holidays or
MaintenanceTroublesBeam
Tunni ng

4000

Non-Nucl.
Phys. Res.

3000
Nucl. Phys.
Res .

2000
1000

o

' 87

'88

'89

'90

'91

'92

'93

'94 '95

'96

'97

'98

'99

(Year)

Fig. 1. Statistics of the RRC operation during the twelve years from 1987 to 1999.
Sumiju Accelerator Service , Ltd.

4

Table 2. Acceleration Conditions for 5.5 MeV/nucleon 86Kr beam.
RF
Frequency

Cavity No.
of RILAC

Harmonics
ofRRC

ChargeStripper

18.7 MHz

3

13

No useBeam Intensities (p~)
Ion Source
Entr. of RRC
Target
6*

1.96

1.2

*18GHZ ECR*Enrichment 90%

The first two of them are acceleration cavities, whichwere designed as the first unit of the CSM and completed in March of 1999. Their frequency tunable
range is 36 to 78 MHz. On the other hand, the otherfour cavities, which have been fabricated, will be CSM
cavities without a course frequency tuner, operated
only at a frequency of 76 MHz. The entire accelerator
will be installed in June of 2000 and a high-intensity
low-energy beam, such as 6 MeV/nucleon 84Kr beamwith an intensity of more than 2 pJ.LA, will be available with stand-alone operation of RILAC in the autumn of 2000. In connection with this, GARIS will be
moved from the E1 experiment room of RRC to theNo.1 target room of RILAC in June of 2000, and the
RILAC-RRC operation will be stopped from May toAugust of 2000.
Machine troubles in 1999 were related mainly to alayer short in a main coil of the W-sector magnet of
RRC. A beam became unstable periodically in February 1999. Since, at the beginning, the effect was so
small and it lasted for a short duration, thus it wasvery difficult to identify the source of the disturbance.
After the long-term precise measurement of terminal
voltages of each coils as well as a magnetic field, it was
discovered that a very unstable and imcomplete shortcircuit between layers had occurred inside of the lower
main coil in the W -sector magnet.
The main coil consists of eleven pancakes, each ofwhich has a six-turn two-layer coil. Each conductor
was covered with glass insulation tape, and the entire
coil was molded with epoxy resin after being wound

and assembled. After a careful search on a surface ofthe molded coil by the thermoviewing method, the exact position where the layer short had been occuring
was found in May of 1999. Fortunately, it occurred
near the coil surface and also near to the coil terminal. By partially removing epoxy resin, the defective
hollow conductor with a square cross-sectional shapewas exposed. After the corner edge of each conductor
was scraped to create enough space between them, thistrouble was overcome completely.
A new ECR ion source using a super-conducting
solenoid was completed in the summer of this year anda plasma test was started in the autumn. An injection
beam line will be changed for two ECR ion sources, sothat one can be tested while the other can be used for
the AVF cyclotron.
During the shutdown period, improvement of injection system of RRC was done. Two sets of magnetic inflection channels (MIC1 & MIC2) were replacedwith new ones and the size of beam pipe was enlarged
slightly. Beam monitors along the injection line will
be replaced with new types of monitors, preparing forthe high intense beam injection in the future.
The radiation safety system has been changed to a
new system using distributed function via a network.
All the replacement was completed in the end of April.
In June of 2000, the spectrometers of DUMAS ,which are currently installed at the beam line on
RCNP, will be moved to experimental hall E7 in thecooperation with the Center of Nuclear Study of Tokyo
University.

5

RIKEN Accel. Prog. Rep . 33 (2000)

RILAC Operation
E. Ikezawa, S. Kohara, M. Fujimaki, T. Aihara,* T. Ohki,* H. Hasebe,*
H. Yamauchi ,* and M. Kase
During this reporting period, RILAC has been insteady operation and has supplied various kinds of ion
beams for various experiments. Table 1 shows thestatistics of RILAC operation from January throughDecember, 1999. The days taken for overhaul and improvement, as shown in Table 1, include two kinds oflarge works. First, the sub-power station for RILAC
was moved to a new site in order to open space in the
project for a RI Beam Factory. Second, improvementof the rf system of RILAC was carried out. Regular
RILAC operation was discontinued twice, from February 13 through May 28, 1999, and from November 22
through December 10, 1999.
Table 2 summarizes the number of days allotted todifferent research groups. The percentage of beam timeused by the RIKEN Ring Cyclotron (RRC) group was

Table 3. Statistics of the RILAC ion beams delivered using
the Cockcroft-Walton injector.
Ion
B
C
C
N
N
Ne
Ar
Ti

Kr
Nb
Rh

Xe
Ta

Hi

Mass
11

Beam time

%

121

33.2

Overhaul and improvement

134

36.7

Periodic inspection and repair

24

6.6

Machine trouble00.0

Scheduled shut down

86

23.6

365

100

Total

Table 2. Beam time allocated for different research groups.
Days%

Atomic physics

15

12.4

Nuclear physics

2

1.7

Radiation chemistry

16

13.2

Material analysis and development

12

9.9

Instrumentation

8

6.6

Accelerator research

5

4.1

Beam transport to RRC

63

52.1

121

100

Total

Sumijyu Accelerator Service, Ltd.

6

3

12

1,4

13

1,2
4
4
4
8
5
13
12
16
15
16
16

14
15
20
40
48
84
93
103
136
181
209
Total

Table 1. Statistics of RILAC operation from January 1
through December 31, 1999.
Days

Charge states

Days

2
7
2
4
2
4
2
1
6
3

2
4
41

Table 4. Statistics of the RILAC ion beams delivered using
the new preinjector.
Ion
0
Ar
Fe
Ni
Kr
Kr
Xe

Mass

Charge states

Days

16
40
56
58
78
84
136

4
8
8,11
9
18
10,11,17
18,20,27

2
9
3
10
2
23
31
80

Total

approximately 52% of the total. The 58Ni, 84Kr, 136Xe,
181Ta, and 209Bi ions accelerated by RILAC were injected to RRC. Tables 3 and 4 show the statistics ofthe number of days of the RILAC ion beams were delivered using the Cockcroft-Walton injector with an
8 GHz ECR ion source (NEOMAFIOS) and thosedelivered using the new preinjector (consisting of an
18 GHz ECR ion source and a variable-frequency RFQ
equipped with a folded coaxial resonator), respectively.
The ion beams of 15 elements were used for the experiments and beam acceleration tests. The percentage
of beam time using metallic ions amounted to approximately 21 % of the total.
We carried out the following machine improvements
during this reporting period.
(1) The No.6 and No . 5 rf systems were replacedwith newly designed ones in May 1999 and in De-cember 1999, respectively. The power amplifier chainof the new rf system consists of a solid-state amplifier (1 kW) as the first stage, a tetrode (SIEMENSRS2012CJ) as the second stage (15 kW), and a tetrode(SIEMENS-RS2042SK) as the final stage (300 kW).
The basic design is similar to that of RRC.
(2) A PC-based control system has been adopted forthe new rf system. Windows NT is used as the operating system of the personal computer. The systemcommunicates with programmable logic controllers by
InTouch software.
(3) Three sets of plate power supplies as the final
stages were replaced with newly designed ones in May
1999, because they were worn out from many yearsof operation. Rated output power is 480 kW for theNo.1 and No.2 rf systems, 700 kW for the No.3 andNo.4 rf systems, and 1120 kW for the No.5 and No.
6 rf systems. Maximum output voltages are 12 kV,
14 kV, and 16 kV, respectively. The ripple voltage at
the rated full load is 0.5% peak to peak.
(4) The power supplies for the bending magnet andquadrupole magnets of the beam transport line fromthe 450 kV Cockcroft-Walton injector were replacedwith new ones, because they were worn out from many
years of operation. Each new magnet power supply isa switching type.
(5) A PC-based control system for the new magnet power supplies was developed. This new system
uses a personal computer with a Windows NT operating system and an application program (HP-VEE).
Each new magnet power supply has a GPIB interface
module, and is connected to Ethernet LAN through
LAN/HP-IB Gateway E2050. The control system has
been used since September 1999.
We experienced the following machine troubles during this reporting period. (1) A GPIB card of thecomputer system controlling RILAC had trouble; wereplaced it with a spare one. (2) The No. 4 resonator had a small vacuum leak at the outer wall of
the rf feeder. (3) A power supply for the filament(4.5 V, 1640 A) of the final vacuum tube (No.1) had
trouble.

7

8

III.

RESEARCH ACTIVITIES1. Nuclear Physics

RIKEN Accel. Prog. Rep. 33 (2000)

Reaction -Mechanism and· Characteristics of T 20 in 'd + 3 He Backward
Elastic Scattering at Intermediate Energies
M. Tanifuji,*l S. Ishikawa,*l Y. Iseri,*2 T. Uesaka, 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
NUCLEAR REACTION, 3He(d~3He)d, Ed = 140,200,270 MeV, PWIA with one-proton-j[exchange
For the last few decades, the tensor analyzing power,
T20, of the backward elastic scattering of deuterons
by protons (d + p) at intermediate energies has been
intensively studied as an important source of information about nuclear interactions and reaction dynamics.
Since 3He has the same spin as proton, the spin structure of the scattering amplitude of the d+ 3He system
is similar to that of d+p when 3He is considered to bea single body. Thus, the backward elastic scatteringof the deuteron by 3He has attracted our attention forinvestigations of probable differences as well as similarities of information when compared to dp scattering. 1)
A d+ 3He experiment was carried out at the RIKEN
Accelerator Research Facility using polarized deuteronbeams of Ed = 140-270 MeV. The beam was provided
by a high-intensity polarized ion source. Three polarization modes (unpolarized and two tensor-polarizedmodes) were cycled every 5 seconds. The beam polarization was measured with a polarimeter based on
d+p elastic scattering. It was continuously monitored
during a run, and found to typically be 60- 80% of theideal value. Scattered 3He particles were momentumanalyzed in the magnetic spectrograph SMART and
detected by a multi-wire drift chamber and plastic scintillators placed at the focal plane. In an off-line analysis, data for (hab ::; 1.4° were used. The background
spectrum from the (d, 3He) reactions on Havar foils was
subtracted to obtain the net yield for d+ 3He events.
The signal-to-noise ratio at the peak region was 5-25,
depending on the beam energy.
In the d+p backward scattering, the assumption ofa mechanism by neutron transfer from the deuteronto the proton has been fundamentally successful in explaining the energy dependence of the observables. For
example, a simple PWIA calculation by the mechanism qualitatively describes the features of the measured tensor analyzing power, T 20 , and the polariazation transfer coefficient, K~ (d ----4 p), at a few hundred
MeV. In the case of a 3He target, the possible reaction
mechanism of the backward scattering of the deuteron
would be proton transfer from 3He to the deuteron.
For the transfer assumption,

T20 = {2v2R cos 8 - R2 - 32R,2+ 12RR' cos(8' - 8)}INR ,*1

Department of Physics , Hosei University*2 Department of Physics , Chiba Keizai College

0.3

0.0 I-::::::::....----tt---..:.,...~----------_+_t

;

· 0.3

,.,

,

' ... .

;j--'- ----_.-_._.---.- ~ .':i.. .. ~.)'.- .. -

"

·0.6

0.0

0.2

0.4

1.0

0.8

0.6

k (GeWe)

Fig. 1. T20 in d+ 3 He backward elastic scattering as a function of the p-d relative momentum in 3He, k.

with
N R = v2 + 2v2R2 + 34v2R,2 - 4R' cos 8',

where Rand R' are the magnitudes of the tensor scattering amplitudes relative to the scalar one; 8 and 8'
are their relative phases. In PWIA, Rand R' 'are given
by

.
WIth

w(k)

r = u(k) ,where u(k) and w(k) are the S- and D-wave functionsof the p-d relative motion in 3He, respectively. The p-d
relative momentum in 3He, k, is related to the incident
deuteron momentum, kd, as k = ~ kd. The 3He wave
function was obtained by solving the Faddeev equation with the AV14 nucleon-nucleon potential. 8 and
8' were treated as flexible parameters which describe
the effects of the virtual excitation of other reaction
channels.
Figure 1 shows the calculated and measured T 20 asa function of k, where the dashed, dotted, solid anddash-dotted lines are for 8' = 60°,120°, -60° and- 120°, respectively, e being fixed at 60°. All calculations with e = 60° describe well the present data,suggesting the importance of deuteron breakup effects.
The resonance-like structures around k = 0.4 GeV Ic in
the solid and dash-dotted lines stimulate us to conduct
an experimental examination if they are observed.
References
1) M. Tanifuji et al.: Phys. Rev. C 61, 024602 (2000).

9RIKEN Accel. Prog. Rep. 33 (2000)

Structure of Li 'Isotop'es Studied by Gaussian Single-Particle Bases
S. Haruyama, T. Otsuka, K. Varga,* and T. Mizusaki[Unstable nuclei, Clustering]
Each Li isotope has its own distinctive feature. For
example, 7Li has a clustering structure and 11 Li has a
halo structure. We have tried to calculate the structures of Li isotopes with some Gaussian single-particle
bases in order to explain these features systematicallywith only a few assumptions.
We have adopted a Gaussian function as a singleparticle wave function,'P~(r)=:

2 ) 3/4(..--..
c

-.:;
E
Q.)
E
E

3

0

()

2

.~

c:::
0>
rn

~

exp (-v(r - 8)2) 1;3),

where 1;3) is the spin-isospin wave function and v is theGaussian size parameter; vector 8 shows the center of
the Gaussian. Here, 1/ and s are variational parameters. There was no variational parameter on the spinisospin wave function in this work. We made a basis
function of a nucleus by a Slater determinant:Q.)~..--..
:::JE-0ro(l):::J ---0'_

4

Argonne National Laboratory, USA

10

6

7
8
Mass Number

0.2 ~ .
-2~E
t5 o ·LI}E -4('Pi (rd = 'P~\ (ri)) .

Here, {Iwi)} are non-orthogonal bases. The coefficients, {cd, were determined by diagonalization of the
Hamiltonian.
We selected parameters of the wave functions in astochastic manner. We also projected wave functions
onto eigenstates of the angular momentum and parity.
In calculations of stochastic selections and projections,
we used a parallel computing machine, called Alphleet.
In this study, we used a Modified Volkov No. 1
Force 1 ) (m = 0.58, b = 0.15, h = 0.05) as the central force and the G3RS force 2 ) as the spin-orbit force.
We used a Coulomb force approximated by the sum ofseven Gaussians.
We calculated the structures of the 6Li, 7Li, 8Li and
9Li ground . states. In the process of selecting basis
wave functions, the z-component of the angular momentum .and parity were projected. After we selectedwave functions, we projected then onto the eigenstateso2Iw) = A{'Pdri)} = det{'Pdri)},

We expressed the wave function of the total system
by superposing multi non-orthogonal many-body basesthat have different Gaussian size parameters,(b)

9

Fig. 1. Magnetic dipole (a) and electric quadrupole (b)moment of Li isotopes. The experimental data are indicated by the circles. 3 )of the total angular momentum and calculated the energies and moments. We show the calculated values ofthe magnetic dipole moments and electric quadrupole
moments in Fig. 1.
These calculated values show good agreement withthe experimental values, although the calculated valueof the magnetic moment of 8Li, 0.956, is smaller thanthe experimental value, 1.65. We suppose that thisdisagreement occurs because the spin wave function
had no variational parameter in this work.
References
1) A. B. Volkov: Nucl. Phys. 74, 33 (1965); T. Ando, K.
Ikeda, and A. Tohsaki-Suzuki: Prog, Theor, Phys. 64,
1608 (1980).
2) N. Yamaguchi, T. Kasahara, S. Nagata, and Y. Akaishi:
Prog. Theor. Phys. 62 , 1018 (1979); R. Tamagaki: Prog.
Theor. Phys. 39, 91 (1968).
3) P. Raghavan: At. Data Nucl. Data Tables 42, 189. (1989).

RIKEN Accel. Prog. Rep. 33 (2000)

Molecular-Orbital Structure In Be Isotopes
N. Itagaki, S. Okabe, and K. Ikeda[Cluster structure, Magic number]
Recently, the contributions of higher shells were analyzed in N = 8 nuclei. A calculation based on theshell model has shown that the slow ,6-decay of 12Be
to 12B can be explained as being due to an admixtureof the excitations from the p shell to the sd shell in
12Be (N = 8), where the single-particle energy is artificially modified. 1) This shows that the concept of magic
number is vague in 12Be. There have been pioneeringstudies for Be isotopes based on the molecular-orbit(MO) model,2-4) although the ground state of 12Be
has been analyzed to be dominantly the closed p-shell
configuration for the neutrons. Here, we propose a new
Q+Q+n+n+··· model based on MO, where the model
space for the valence neutrons is vastly extended.
In MO, the orbits for the valence neutrons are expressed as a linear combi!lation of orbits around eachQ-cluster. When a linear combination of two p-orbits
around the left-Q-cluster and the right-Q-cluster issummed up with the same sign, the resultant MO state
has negative parity and one node. It cannot spreadalong the z-axis where two Q-clusters are already located. If a linear combination of the p-orbit is summed
up with the opposite sign, the resultant J\;10 state has
two nodes and positive parity. The optimal directionof this MO becomes the Q-Q direction. In this way,
three basic orbits (K7r = 3/2-,1/2- (one node) and
4+12
4+-

W?)-

10
(2+)-

8 Be +n+ n

8

:>
6

4--

a't--2+
4't-1't--3+ 2+-

2't--

3--

0+-

1-- 2-

3--12

2-4-10
3--

0+-

1-~-

8

Q)

6

2L--

6

2't--

>-

OJ

CD
c:

W

4

4
2+-

2't--

2

o

2

-0--1:.....- - - - - - - - - - - - - - - - - - - - - - -<1"- - - - - - - - - - - - - - - - - -Experiment0

Calculation

Fig. 1. Calculated and experimental energy levels of lOBe.
The calculated levels are sorted into five columns. Fromleft to right: states whose dominant component is K7r =0+, 2+, and 1+. The fourth column is the second 0+
band characterized by the a-orbits. The fifth column isthe negative parity band.

1/2+ (two nodes)) for the valence neutrons are introduced. These orbits are described by a superpositionof the local Gaussians, whose positions are determinedvariationally for each Q-Q distance before the angularmomentum projection.
As an effective two-body N-N interaction, we introduce the Volkov No. 2 potential with M = 0.6,
B = H = 0.125 for the central part, and the G3RS potential with the strength parameter V = 2000 MeV forthe spin-orbit part. These parameters are determinedfrom the Q-Q, Q-N and N-N scattering phase-shifts.
First, we applied the model to lOBe (Q+Q+n+n);
the calculated energy levels are displayed in Fig. l.5)
The ground 0+ state (-61.1 MeV) has dominantly the(3/2-)2 component for the two valence neutrons, andthestate at 8.1 MeV (experimentally 6.263 MeV)
has dominantly not the (1/2-)2 component, but the(1/2+)2 component. Thus, the level inversion of thep-shell and the sd-shell is also found to be reflected inlOBe. The second 0+ state has a much larger charge
radius of 2.93 fm, (a proton radius of 0.813 fm isused), than the ground state, 2.51 fm, since the two valence neutrons occupy a higher nodal orbit along the
Q-Q axis and increase the distance between the two
Q-clusters so as to reduce the kinetic energy of the system. The state is the band head of enhanced clustering
states.
This (1/2+)2 configuration is also strongly mixed in
the ground state of 12Be. When the Q-Q distance issmall, for example 2 fm, the dominant configuration of
the last two valence neutrons is (1/2-)2 for the groundstate, which corresponds to the p-shell closed configuration at the limit of Q-Q distance of zero. However,the (1/2+)2 configuration for the last two valence neutrons becomes lower as the Q-Q distance is increased.
At an Q-Q distance of 3 fm, which is the optimal distance for 12Be, the ground 0+ state has a squared overlap of 0.41, with (1/2-)2, and a squared overlap of 0.64
with (1/2+)2. Therefore, in the ground state of 12Be,
two different configurations contribute, and the neutron magic number, N = 8, disappears.
One evidence of the mixing of the (1/2+)2 component is the ,6-decay probability from 12Be to 12B. Using the present model, the log(ft) value of 12Be(0+) -+12B(1 +) is calculated to be 3.81; this value agrees withthe experimental value of 3.8. However, if we restrict
the configuration of the last two valence neutrons to(1/2-)2, the log(ft) value becomes 3.51. Therefore,
the mixing of the (1/2+)2 component is found to suppress this transition and to increases the log(ft) value.

ot

11The agreement of the experimental and the theoreticallog(ft) values suggests that the breaking of the N = 8
magic number is realized in 12Be.
References
1) T. Suzuki and T. Otsuka: Phys. Rev. C 56 , 847 (1997).
2) Y. Abe , J. Hiura, and H. Tanaka: Prog. Theor. Phys .
49, 800 (1973).

123) H. Furutani, H. Kanada, T. Kaneko , S. Nagata, H.
Nishioka, S. Okabe, S. Saito , T . Sakuda, and M. Seya:
Prog. Theor. Phys. Suppl. 68 , 193 (1980) .
4) M . Seya, M. Kohno, and S. Nagata: Prog. Theor. Phys.
65 , 204 (1981).
5) N. Itagaki and S. Okabe: to be published in Phys. Rev.
C.

RIKEN Accel. Prog. Rep. 33 (2000)

Model-Independent Analysis of the One-Body Densityof Unstable Nuclei
A. Kohama, S. Yamaji, R. Seki, * and A. Arima[Unstable nuclei, Matter distribution, Proton-nucleus elastic scattering]
We have analyzed the matter distribution of unstable nuclei model-independently based on the experimental data of proton-unstable-nucleus elastic scattering. We applied the method of Friar and Negele.1)
This method was originally proposed to determine thecharge distributions of stable nuclei.
Since the first observation,2) the reaction cross sections of neutron-rich light nuclei have been found to
be quite large. This suggests an extended structureof the neutron-rich nuclei; information concerning theone-body matter distribution is indispensable to prove
this hypothesis.
In the formulation of Friar and Negele , the one-bodydensity, p(r), is expanded in terms of the FourierBessel series. No assumption is made concerning theform of the density. The expansion coefficients are determined by minimizing X 2 , defined as
1
X=~~
2

N
"""

0=1

0

(aexp ath ) 2

0

0

dO-dO

Here, N is the number of data points , and Eo isthe error of each data point. The superscript "exp"ofthe cross section implies the experimental data, and"th" implies the theoretically obtained value. We use

the expression of the first-order optical potential in
the Glauber approximation for the theoretical crosssection in this work. It includes the one-body density
explicitly. 3)
Detailed numerical calculations are in progress. We
simply point out that the previous work on the determination of the matter distribution of 6He and 8He 4 )may still be too naive. 5 ) The authors first assume
the function form of the density, and then make aparameter-fit using the experimental data. Byassuming the function form, theoretical prejudice could be
brought into the analysis, which is not a good way totreat this kind of problem. Presently, the available
data do not give the density with sufficient accuracy
in our formulation.
References
1) J. L. Friar and J. W. Negele: Adv. Nucl. Phys. 8 , 219(1975).
2) I. Tanihata et al.: Phys. Lett. B 160, 380 (1985).
3) A. Kohama, S. Yamaji, R. Seki , and A. Arima: in preparation.
4) G. D. Alkhazov et al.: Phys. Rev. Lett. 78, 2313 (1997).
5) R. Seki and I. Tanihata: preprint (1999).

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

13

RIKEN Accel. Prog. Rep . 33 (2000)

Development of a New Code for Large-Scale Shell-M9del
Calculations Using a Parallel Computer
T. Mizusaki[Shell model, Parallel computation]
The nulcear shell model is a fundamental framework for describing interacting nucleons. Therefore,
many efforts have been devoted to solve the shell-model
problem. Among these efforts, a numerical approachis quite important, especially for realistic shell-model
calculations. Due to the recent rapid progress of computer technology, several numerical methods 1 ,2) are being advocated, and can, indeed, come over the limitation of the conventional shell-model diagonalization in
many respects. However, up to now, only a shell-model
diagonalization method can grantee an exact (not approximate) solution in the case where a shell-model
calculation is possible. t Therefore, shell-model diagonalization still keeps its unique value in a nuclear spectroscopic study. In addition, shell-model diagonalization, itself, can also be further developed by the use ofmodern computational technology.
In this paper, we present the current largest shellmodel calculations based on a new shell-model codewith a massively parallel computer, called Alphleet.+
Alphleet was originally designed for Monte-Carlo shellmodel (MCSM) 1) calculations. In the MCSM, the numerical intensive part is an angular-momentum projection, performed by three-fold integration over theEuler angles. The strategy of parallel computation isdivision concerning the Euler angles. This parallelization is quite easy and its efficiency is quite high. On
the other hand , efficient parallelization of shell-model
diagonalization is difficult because it requires a quite
huge amount of numerical data. In the distributed
memory system, huge data transfer among CPU 's is inevitable. By developing an algorithm which minimizes
the data-transfer during shell-model diagonalization,a new shell-mode code on such a distributed memory
system becomes efficient. For instance , by 24 CPU's,
we can solve the shell-model problem with 0.1 billion
dimension. In this case, one Lanczos iteration requires
about 6600 seconds. Then, a converged solution canbe obtained within few days. The computational time
will be further shortened by using a larger number ofCPU's.
In Fig. 1, we show the pf-shell calculations ofIn the SMMC method , a notorious minus sign problem induces a large error bar for the ground-state energy, as shownin Fig. 1. In the MCSM method, its energy is quite precise,but is still variational upper limit
Alphleet is a customized parallel computer in the RI Beam
Factory in RIKEN

14

>v

-165

6

SMMC

~ -170I
106dimension

10

8

I

f

MCSM

Fig . 1. Yrast energy levels in 54Fe as a function of thedimension.

54Fe with the FPD6 interaction for 0+- 10+ , as an
example. The energy eigenvalues are shown as afunction of the dimension of the truncated shellmodel space, defined by EBs~t (h /2 )A-40-S (r)S, wherer means the 15/2 , P3/2 and P1/2 orbits and t is the maximum number of particle allowed to be excited. The
dimension is counted for Jz = 0 space. The results of
SMMC and QMCD methods for the ground-state arealso added as a reference. As the truncation space becomes larger , the eigenvalues converge. Consequently,
such a large-scale shell-model calculations are shown
to be quite useful for the yrast spectroscopy of the pf
shell region.
In summary, a new shell-model code has been developed, which is well optimized for massively parallel computers. By this code, shell-model calculations
with over 0.1 billion dimension become possible, andthe realm of full pf-shell calculations becomes enlarged.
References
1) M. Honma, T. Mizusaki, and T. Otsuka: Phys. Rev.
Lett. 75, 1284 (1995).
2) S. E. Koonin, D . J. Dean, and K. Langanke: Phys. Rep.
577, 1 (1996).

RIKEN Accel. Prog. Rep. 33 (2000)

Monte' Carlo Shen~Model Study of Unstable Nuclei Around 'N

20t

Y. Utsuno, T. Otsuka, T. Mizusaki, and M. Honma[NUCLEAR STRUCTURE shell model, Shell gap]
The N = 20 closed-shell structure is known experimentally to disappear in the neutron-rich region, for instance, by the 2t level!) and the large B(E2; ot -4 2t)
valtie 2) of 32Mg. The aim of this study was to clarify
the mechanism of the vanishing shell gap in terms of
the shell model. Because the shell-model dimension
is too large to diagonalize the shell-model Hamiltonian exactly, we adopted the Monte Carlo shell-model
calculation. 3) Since it is desirable to make a systematic calculation in this region to examine the mechanism, we performed shell-model calculations, in asingle framework , for even-even nuclei from 0 to Si.
The computations were carried out mainly using theAlphleet computer system at RIKEN.
Figure 1 shows the number of neutrons excited fromthe sd shell to the p f shell for the ground states of
Ne, Mg, and Si isotopes. Particle-hole excitation occurs considerably around N = 20 for Ne (Z = 10) andMg (Z = 12) isotopes , while the ground state of Si(Z = 14) primarily consists of the normal configuration. We note that the calculated states successfully
reproduce the energy levels and the B(E2) values.
3,.-....

0

>
Q)

~
"-"
~
~

CI}

-10

Q)

>
......
+->
C,)

~

4-i
Q)

-20
8

10

12

14

16

18

20

Z
Fig. 2. Effective neutron single-particle energies for N = 20
isotones as a func t ion of the proton number.

In order to analyze the result, the effective singleparticle energy (SPE) is very useful. Assuming thenormal configuration for N = 20 nuclei, we define theeffective SPE of a given orbit as the one-neutron separation energy from this orbit, and then the energy
is evaluated by the monopole interaction of the shellmodel Hamiltonian. From Fig. 2, it can be seen thatthe shell gap between Od3 / 2 and Of7/2 becomes wider as
Z increases, whereas the gap is quite small for Ne andMg isotopes. This occurs because the strong protonneutron monopole interaction within the same major
shell (sd shell) stabilizes the N = 20 shell closure.
We suggest that the narrow gap between the sd andp f shells is a cause of a vanishing of the dosed-shellstructure in the neutron-rich Ne and Mg isotopes , together with a preference for a prolate deformation ofthese isotopes.
References

Fig.!. Average number of neutrons in the pf shell subtracted by the corresponding number in the normal(i.e., filling) configuration. The triangles, diamonds,
and circles stand for the values of the Ne, Mg, and Si
isotopes, respectively. The solid line denotes the corresponding value of the N a and Mg isotopes, as predictedby the "island of inversion" of Ref. 4.

1) D. Guillemaud-Mueller et al.: Nucl. Phys. A 426, 37(1984).
2) T. Motobayashi et al.: Phys. Lett. B 346, 9 (1995).
3) T. Otsuka, M. Honma, T. Mizusaki: Phys. Rev. Lett.
81, 1588 (1998) and references therein.
'
4) E. K. Warburton , J. A. Becker , and B. A. Brown: Phys.
Rev. C 41, 1147 (1990).

Condensed from the article in Phys. Rev. C 60, 054315(1999)

15

RIKEN Accel. Prog. Rep. 33 (2000)

A 'Search for a Unified Effective Interaction for Monte Carlo
Shell-Model Calculations
M. Honma, B. A. Brown,* T. Mizusaki, and T. Otsuka[Shell model, Effective interaction]
The nuclear shell model has been successful as oneof the most fundamental models of nuclei. It has been
demonstrated by p- and sd-shell calculations that, oncea suitable effective interaction is found, the shell model
can describe various nuclear properties both accurately
and systematically in the whole major shell. In suchcases, the shell model acquires predictive power; one
can see an indication of new physics in any possible
deviation of new experimental data from shell-model
predictions. For such systematic studies, it is crucially
important to find a reliable effective interaction which
can properly reproduce the variation of the nuclear
structure over a wide mass-range.
On the other hand, the conventional shell-model diagonalization in a complete one-major-shell has beenpossible only up to the sd-shell, since the dimensionof the Hamiltonian matrix becomes too large to diagonalize for larger shells. In order to overcome this difficulty, we have proposed the Monte-Carlo shell model(MCSM)l) based on the quantum Monte-Carlo diagonalization (QMCD) method. In MCSM calculations,basis states are generated stochastically, and are either
adopted or discarded according to its importance forthe energy gain. The Hamiltonian matrix is then diagonalized in a subspace spanned by these small numberof selected basis states. By using MCSM we can carryout shell-model calculations in the pf- and larger shells
with reasonable accuracy.
For the pf-shell nuclei, various effective interactions
have been investigated. For example, the KB2) interaction has been constructed on the basis of the G-matrix
derived from an NN-potential. However, for quantitative studies, such a realistic interaction requires sizable empirical corrections to its monopole part. The
monopole-modified G-matrix interaction (KB3)3) has
been found to be successful in the lighter half of the
pf-shell (A ::; 52). However, the KB3 interaction isdangerous to use beyond 56Ni, because of its too-large
shell gap above the f7 / 2 orbit. A different strategy istaken for the FPD6 4 ) interaction, where an analytic
form of the two-body potential, which contains several
parameters, is assumed; these parameters are determined by a fit to the experimental data of A = 4149 nuclei. The FPD6 interaction is quite successful
for describing heavier pf-shell nuclei, such as 64Ge and56Ni. The difficulty of the FPD6 interaction is foundin the single-particle properties (a too-low £5/2 orbit),which can typically be seen in 57 Ni. There are several
other effective interactions for pf-shell nuclei, whichhave been evaluated with a certain truncation of themodel space.
However, such a truncation restricts the applicability and predictive power of the shell model to several
limited cases. Thus, it is a quite challenging problem toinvestigate whether it is possible to construct a unified
shell-model effective interaction for pf- and larger shells
which can describe various nuclear properties systematically over a wide model space, including both the
beginning and the middle of the shell. MCSM enables
us to study such a problem. Since MCSM utilizes general deformed bases, we can consider the whole model
space without any truncation.
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, leading to success concerning the USD
interaction. 5) In the USD interaction, 63 two-body matrix elements and 3 single-particle energies were fixed
in a fit to 447 energy data with an rms deviation of
185 keY. Practically, the 47 best-determined linear
combinations of parameters were determined in a fit,
and for the remaining 19 linear combinations the corresponding values of the G-matrix interaction were used.
In the case of the pf-shell, 195 two-body matrix
elements and 4 single-particle energies should be determined. Although the number of parameters becomes about 3-times larger than that of the sd-shell,
this method is still applicable if we can take a sufficiently large number of data. The shell-model calculations were carried out by a massive parallel machine,
Alphleet, at RIKEN. By taking 742 energy data wehave obtained a fit with an rms deviation 254 keY. We
are now searching for a better set of parameters bychanging the data selection and the number of linear
combinations to be determined by a fit.
References
T. Otsuka et al.: Phys. Rev. Lett. 81, 1588 (1998).
T. T. S. Kuo et al.: Nuel. Phys. A 114, 241 (1968).
A. Poves et al.: Phys. Rep. 70, 235 (1981).
W. A. Richter et al.: Nucl. Phys. A 523, 325 (1991).
B. A. Brown et al.: Ann. Rev. Nucl. Part. Sci. 38, 29

1)
2)
3)
4)
5)

(1988) .
Michigan State University, USA

16

.!

RIKEN Accel. Prog. Rep. 33 (2000)

Monte Carlo Shell-Model Calculations for Medium-Heavy Nuclei
N. Shimizu, T. Otsuka, T. Mizusaki, and M. Honma[Shell model , Nuclear structure, Collective motion, Computational physics]
It is known that a part of the even-even nuclei
around the rare-earth region shows a shape-phase transition, which is nothing but ·a gradual variation in thespherical-deformed change of the nuclear shape withincreasing neutron number . The properties of these
nuclei have been well studied using the Interacting
Boson Model (ex. see Ref. 1). The purpose of thisreport is to discuss this intriguing structure change
by utilizing a nuclear-shell-model description involving
fermions, not bosons.
We have focused on 138- 150 Ba isotopes, which areamong the above-mentioned nuclei. The single-particle
states of the nuclear shell model consists of N = 82132 and Z = 50- 82. The effective interaction which
we have used consists of the paring-type, quadrupolepairing-type and quadrupole-quadrupole-type interactions whose parameters were fitted for the excitationlevels of semi-magic nuclei, except for the protonneutron quadrupole-quadrupole interaction. We restricted the shell-model Hilbert space to that with anaxially symmetric deformation, which is considered to
be a good approximation for these nuclei. Since Hilbert
space is too huge to use the conventional shell-model
diagonalization method, we have used the Monte-Carlo
Shell Model method, which was recently developed by
M. Honma et al. 2 ) in order to overcome such a difficulty. In addition, we revised the method so as toutilize pair-bases.
Figure 1 shows a comparison between the experimental values and the MCSM results for the 2+ , 4+ ,6+, 8+ , 10+ levels of Ba isotopes. The experimental

4...

•" " " " "-

>
Q)

~

x
W

•

"-

"-

"-

\

'\

2

Neutron number

Fig. 1. Energy levels of Ba isotopes. The symbols and lines
denote the experimental values and theoretical results,
respectively.

energy levels show transition from vibrational nuclei(left-hand side) to rotational nuclei (right-hand side).
We can see that the theoretical results reproduce sucha character quite well.
These computations have been carried out mainly
using the Alphleet computer system at RIKEN.
References
1) O. Scholten: Phys. Rev. C 28, 1783 (1983).
2) T. Otsuka, M. Honma, and T . Mizusaki: Phys. Rev.
Lett. 81, 1588 (1998) and references therein.

17

RIKEN Accel. Prog. Rep . 33 (2000)

The .N ucleon Pair Approximation of the Shell Model
Y. M. Zhao, S. Yamaji, N. Yoshinaga, and A. Arima[Nucleon pair approximation, Shell model, Collective excitations]
We have completed a series of studies l - 4 ) on the nucleon pair approximation of the shell model. S )Firstly, the validity of the SD- pair truncation of theshell model was tested in a single-j shell and many-jshells within the framework of the nucleon pair shellmodel. It has been found that SD-pair truncation is agood approximation of the shell model in the singlej case when the Hamiltonian consists of (monopoleand quadrupole) pairing plus quadrupole-type interactions. The SD-pair truncation deteriorates if the
QQ-type interaction is artificially large compared withthe monopole pairing interaction. For multi-j shells,
schematic calculations in the degenerate sd, pj, andsdg shells were performed for the extreme case of apure QQ-type interaction. There is a large difference
between the binding energies in the SD- pair truncatedsubspace and those calculated in the full shell-model
space, as in the case of a single-j shell. However , it
has been found that the basic properties of the band
structure remain intact, and that the difference in theenergy levels, i.e., moments of inertia, can be easily
absorbed by adjusting the interaction strengths.
Secondly, calculations using the nucleon-pair shellmodel were performed in terms of the SD collective
pairs , which were obtained in a suitable way to obtainthe maximum collectivity. This method was applied
to even-even Sn, Te , Xe, Ba, and Ce isotopes near theA = 130 region using the (monopole and quadrupole)pairing plus quadrupole-type interactions by adjustinga very few parameters. The structure of the energy
levels for the quasi gamma band as well as the groundband has been well reproduced for each nucleus. Other
properties, such as B(E2) 's , agree with the experimental data very well. The calculated nuclear radii are wellconsistent with the relativistic mean-field calculation.
The overall fit with the experimental data is superior
to that of the previous calculations.
Thirdly, we investigated the role of the singleparticle energies on the low-lying states of 13 2 Ba, atypical 0(6) nucleus in the IBM and the FDSM. It
has been found that one can usually "restore" thephysics of a realistic problem with non-degenerate
single-particle energies using degenerate single particle
levels and a slightly different parametrization of thetwo-body interaction. However, if the single-particle

18

splittings are enlarged by a factor of 1.5, the 0(6) behavior of the nucleus is lost and a model that assumes
degenerate levels cannot describe its collective structure. The contributions from interactions other thanmonopole and quadrupole pairing and quadrupolequadrupole interactions have been found to be unimportant for the low-lying states. Although the role of
the abnormal parity level depends on the details of thesingle-particle structure, its effects can be "compensated" by using different Hamiltonian parameters anddegenerate single-particle levels in the FDSM treatment.
Fourthly, the Wick theorem for coupled Fermion
clusters has been used to derive the nucleon-pair approximation for an odd nucleus. The building blocksof the model space were constructed using one unpaired valence nucleon coupled with the collective nucleon pairs stepwisely. Analytical expressions for the
related commutators were derived , and formulas were
given for the matrix elements of a general Hamiltonian.
The formalism for an odd system was presented in asimilarly recursive way as the even system. By treating the two-body interaction as an integrated operator in the re-arrangement of the operators before computing the related commutators, the computing timeof a general two-body interaction matrix elements iscomparable to that of the one-body interaction matrix
elements , which is crucial for the nucleon pair approximation of an odd system to be realizable. This formalism unifies the analytical expressions of the Hamiltonian for an even system and an odd system (including odd-even, even-odd , a~d doubly odd cases).
We call this "the unified formalism for even and odd
systems" .
References
1) Y . M. Zhao, N. Yoshinaga, S. Yamaji , and A . Arima:
Phys. Rev. C, to be published.
2) Y . M . Zhao, S. Yamaji, N. Yoshinaga, and A. Arima:
Phys. Rev. C, to be published; RIKEN Aeeel. Prog.
Rep. 32, 18 (1999).
3) Y. M. Zhao, N. Yoshinaga, S. Yamaji , and A . Arima:
Phys. Rev. C, to be published.
4) Y. M . Zhao, N. Yoshinaga, S. Yamaji, J. Q. Chen, and
A. Arima: Phys . Rev. C, to be published.
5) J. Q . Chen: Nuel. Phys. A 626, 686 (1997).

RIKEN Accel. Prog. Rep. 33 (2000)

Effects of the Dirac Sea on the Giant Monopole States
H. Kurasawa* and T. Suzuki[Relativistic model, Effects of the Dirac sea, Giant resonance states]
The relativistic mean-field approximation (RMFA)
neglects the Dirac sea in describing the nuclear groundstate. Recently, however, it has been numericallyshown that in a relativistic random-phase approximation(RRPA) built on RMFA, the monopole states cannot be well described without Pauli blocking terms,
which express transitions between the Dirac sea andthe occupied Fermi sea. I) If the blocking terms are neglected, the excitation energies of the monopole states
in RRPA are much lower than those in the timedependent relativistic mean-field approximation. 2)
We show in an analytic way the role of the Diracsea in the excitation energy of the monopole states.
In the relativistic model, the excitation energy of themonopole states is expressed as 3 )EM =(fF7r2)) 1/2,

(1)where tF denotes the Fermi energy and (r2) the rootmean-square radius of the nucleus. The incompressibility coefficient, K, is expressed in terms of the relativistic Landau-Migdal parameters, Fo and FI , as

K = 3p~ 1 + FotF

(2)

1 + ~FI'PF being the Fermi momentum.

In order to see the effects of the Pauli blocking termson the monopole states, we derive the Landau-Migdal
parameters according to RRPA. We calculate the longitudinal RRPA correlation functions with and without the Pauli blocking terms. 4 ) By comparing themwith the correlation function of the Landau theory, we
can obtain the expressions of the Landau-Migdal parameters in each approximation.
Including the Pauli blocking terms, we obtain

F _ _
I -

v~Fv

1 + 1 v 2 F'
3 F

v

(3)

and w-meson, respectively, and M* denotes the effective nucleon mass. NF and VF represent the rel~tivistic
density of states at the Fermi surface and the relativistic Fermi velocity. The factor as, in Fo of Eq. (3), is
given by

a,F, =(2~)3 (::;J2

Jd3p~;

Op,(6)
where Bp denotes the step function, B(pF - Ipl).
If we neglect the Pauli blocking terms, we obtain theLandau-Migdal parameters as(7)

The difference between Eqs. (3) and (7) is very clear.

Fo and FI in Eq. (7) have no denominator. In fact,
we can show that the Landau-Migdal parameters in
Eq. (3) are those from the second derivative of thetotal energy density with respect to the quasiparticle
distribution. In order to obtain correct expressionsof Fo and FI within RMFA, we thus need to include
the Pauli blocking terms in the configuration space of
RRPA.
The values of K were calculated using the following
parameters 5 ) as an example:
M = 939,

ms = 520,

mv = 783 (MeV),g; = 109.626, g; = 190.431,(8)which reproduce the nucleon binding energy, EB =-15.75 MeV, at PF = 1.30 fm-I. In this case, we have
K = 544 Me V by taking the Pauli blocking terms into
account, and K = 357 MeV by neglecting them. Thus,
the value of K is fairly reduced, if the Pauli blocking
terms are neglected. In 208Pb, the reduction amounts
to about 2.7 MeV for the present parameters. This fact
may be observed in Ref. 1 by numerical calculations.

where we have defined(4)N_ 2pF E F
F -

7r 2

'

PF
VF = EF'

EF = (p~ + M*2)1/2.

(5)

In the above equations, gs and gv stand for the Yukawa
coupling constants, ms and mv the masses of the a-

References
1) N. V. Giai and Z. Ma: RIKEN Rev., No. 23, p. 69(1999).
2) D. Vretnar, H. Berghammer, and P. Ring: Nucl. Phys.
A 581, 679 (1995).
3) S. Nishizaki, H. Kurasawa, and T. Suzuki: Nucl. Phys.
A 462, 687 (1987).
4) H. Kurasawa and T. Suzuki: Nucl. Phys. A 445, 685(1985) .
5) C. J. Horowitz and B. D. Serot: Nucl. Phys . A 368,503(1981) .

Faculty of Science, Chiba University

19

RIKEN Accel. Prog. Rep. 33 (2000)

The Phonon Damping Model
N. Dinh Dang, K. Tanabe, and A. Arima
Hot giant dipole resonance, Double and triple giant dipole resonances, Damping, Exotic][nuclei
The Phonon Damping Model (PDM) was proposed
by Dinh Dang and Arima in 1998 1) as PDM-l. Its
further development, which includes all configuration
mixings up to two-phonon configurations, has been
carried out by Dinh Dang, Tanabe, and Arima (PDM2).2) The primary purpose of PDM is to describe thedamping of the giant dipole resonance (GDR) in highly
excited (hot) nuclei. This model has shown that themain mechanism that causes a sharp increase in the
GDR width at low temperatures, T ~ 3 MeV, andits saturation at high temperatures, T > 3- 4 MeV, is
coupling of the GDR phonon to the particle-particle(pp) and hole-hole (hh) configurations, which appear
due to the deformation of the Fermi surface at T #- o.
In PDM, a model Hamiltonian including coupling between the GDR phonon to all ph, pp, and hh configurations at T#-O is used, and the strength function
is calculated directly in the laboratory frame without
any need for an explicit inclusion of the thermal fluctuations of shapes or the angular-momentum effect. The
PDM has been proved to be quite successful in reproducing not only the the width, but also experimentallyobserved shapes of hot GDR in 120 Sn and 208Pb.
Very recently, in order to test the capability of PDM,
we have further developed and applied it to:(1) A statistical analysis of the shape evolution of
hot GDR in 120Sn;3)(2) A study of multiphonon GDRs, especially double
and triple GDRs in heavy nuclei;4)20(3) A study of damping of GDR in neutron-richnuclei. 5)
Our analysis of numerical calculations has shownthat:(1) The GDR shapes predicted by the PDM strength
functions in combination with the calculations 3) are in
overall reasonable agreement with the data from inelastic a-scattering experiments;(2) PDM can account reasonably well for the damping of double and triple GDRs, where a noticeable difference in the damping of the DGDRS in open-shelland double magic nuclei has been pointed out;4,6)(3) PDM is able to describe the damping of GDR in
exotic nuclei. In particular, it shows the appearanceof a low-lying dipole mode in neutron-rich nuclei, like
18,24 0, 60Ca, and 150Sn.5)
References
1) N. Dinh Dang and A. Arima: Phys. Rev. Lett. 80, 4145
(1998); Nucl. Phys. A 636, 427 (1998).
2) N. Dinh Dang, K. Tanabe, and A. Arima: Phys. Rev.
C 58, 3374 (1998); Nucl. Phys. A 645, 536 (1999).
3) N. Dinh Dang, K. Eiseman , J. Seitz, and M.
Thoennessen: Phys. Rev. C 61, 027302 (2000).
4) N. Dinh Dang, K. Tanabe, and A. Arima: RIKEN-AFNP-325 (1999).
5) N. Dinh Dang, T. Suzuki, and A. Arima: RIKEN-AFNP-331 (1999).
6) N. Dinh Dang, K. Tanabe, and A. Arima: Phys. Rev.
C 59, 3128 (1999).

RIKEN Accel. Prog. Rep . 33 (2000)

Statistical Analysis of the Hot Giant Dipole ,Resonancewith the Phonon Damping Model
N. Dinh Dang, K. Eisenman,* J . Seitz ,* and M. Thoennessen*[Giant resonances , Thermal and statistical models]The comparison between theory and experimental
data of the hot GDR is not straightforward. Typically, only the parameters of a Lorentzian strength

30 '--'--~--'-~--~--~-,

E* =

30MeV

Tmax= 1.24 MeV
T. v
1.1 MeV

.=

20
10

10
5
0

E* = 70MeV
Tmax= 2.02 MeV
Tav. = 1.8 MeV

,,-.,

!.l

'§ 10

1
,,-.,

5

;~

I:i:"

0
E* =

90MeV

Tmax= 2.43 MeV
T.v
2.2MeV

.=

10

5
0

E* = 110 MeV
Tmax= 2.79 MeV
T.v
2.4 MeV.=10function (resonance energy, width and strength) are
extracted from the data and compared to the theoretical values. In addition, the conversion of the experimentally measured excitation energy to the temperature which is calculated within theoretical models isdifficult and sometimes can even be misleading as has
been recently discussed. 1,2) Although the importanceof including the temperature dependence of the GDRparameters in the statistical model calculations waspointed out a long time ago , it was not crucial as longas the data were not compared to detailed models, but
only fitted to extract a functional form of the width
increase. Recently, a method has been proposed toincorporate the theoretical strength functions directly
into full statistical decay calculations. 2) This way, notonly the GDR energy and width , but also the entire
shape of the GDR strength functions, can be comparedwith the measured spectra. In this work, we have applied this method to the strength functions of the hot
GDR obtained within the PDM.3)
The strength functions of the hot giant dipole resonance (GDR) in 120Sn, obtained within the phonon
damping model (PDM) , have been included in complete statistical CASCADE calculations and comparedwith their experimental divided spectra as a function of
the temperature, T. The entire experimental shape ofthe hot GDR can be reproduced reasonably well using
the PDM strength functions. The effect of superfluid
pairing at T < 1 MeV is important to obtain better
agreement between theory and the experimental data

(Fig. 1).

5

5

10

15

20

25

30

35

Ey (MeV)Fig. 1. Experimental (shade areas) and theoretical divided
spectra calculated within the CASCADE without pairing (dashed curves) and including pairing (solid curves)at various excitation energies.

References
1) M. P. Kelly, K. A. Snover, J. P. S. van Schagen, M.
Kicinska-Habior, and Z. Trznadel: Phys. Rev. Lett. 82,
3404 (1999).
2) G. Gervais, M. Thoennessen, and W. E. Ormand: Phys.
Rev. C 58, 1377R (1998).
3) N. Dinh Dang and A. Arima: Phys. Rev. Lett. 80, 4145
(1998); Nucl. Phys. A 636, 443 (1998) .

National Superconducting Cyclotron Laboratory, Michigan
State University, USA

21

RIKEN Accel. Prog. Rep. 33 (2000)

Hot Giant Dipole Resonance In the Static Path Approximation
A. Ansari, * N. Dinh Dang, and A. Arima[Static path approximation , Ciant dipole resonances, Thermal fluctuations of shapes]
The effects of the thermal fluctuations of nuclear
shapes on the damping of the hot giant dipole resonance (CDR) have been the subjects of a numberof recent studies. These effects have usually been incorporated so far by averaging the I'-absorption crosssection, cr (E-y ), over all possible q uadru pole shapes using a Boltzman weight factor, e- FIT , where F is thefree energy, which depends on the quadrupole deformation parameters, (3 and 1', and temperature, T . In
the calculations of Ref. 1 the dipole strength function
is computed by a simple deformed harmonic-oscillator(HO) model. At the same time, for thermal averaging,a free energy is used corresponding to the macroscopicmicroscopic Strutinsky shell correction approach incombination with a parametrized expansion following the macroscopic Landau theory of phase transitions. Hence , a particular specific Hamiltonian has notbeen employed to calculate every quantity, such as the
CDR strength function. On the other hand, the thermal averaging can be performed in a consistent manner following the static path approximation (SPA)2)
for the grand canonical partition function using thesame Hamiltonian. The SPA allows one to include
the angular-momentum effects rather easily within thestandard cranking approach. Thus, thermal averaged
values, (fJ) and (1') , can also be computed at given
temperature and spin.
In this work, the CDR was calculated in 120Sn using
the linear response theory incorporating the thermal
shape fluctuations within SPA. This is the first application of such an approach to the CDR in a realistic
nucleus at finite temperature and angular momentum.
A model Hamiltonian with a quadrupole-quadrupole
interaction was used. The obtained results show thatthe thermal fluctuations of quadrupole shapes increase

Institute of Physics, Bhubaneswar, India

22

70
60
50
N

.§

40

;;:..

30

0'

20

w

10
10

15

20

25

30

Ey (MeV)Fig. 1. 1'-absorption cross section, a(E-y) , of the CDR in
120Sn at various angular momenta, J , and temperatures , T. The solid, dashed, dotted, and dash-dottedcurves correspond to the results obtained at (T, J) =(0.4 MeV , 5.24 h), (1 MeV , 7.1 h), (2 MeV, 13.5 h),and (3 MeV , 18.9 h), respectively.

the CDR width by only 40% at T = 3 MeV, compared
to its value at T = O. The effect of the angular momentum on the damping of the hot CDR is found tobe negligible for this nucleus up to T ~ 4 MeV andJ ~ 80 n. The combined effect of temperature and angular momentum leads to a CDR energy that is nearly
independent of the excitation energy (Fig. 1).
References
1) Y. Alhassid and B. Bush: Nucl. Phys. A 531, 39 (1991);
W. E. Ormand, P . F. Bortignon , R. A. Broglia, and A.
Bracco: Nucl . Phys. A 614 , 217 (1997); D. Kuznesov,
Y . Alhassid, and K . Snover: Phys . Rev . Lett. 81, 542(1998) .
2) B. K. Agrawal, A. Ansari , and P. Ring: Nuel. Phys. A
615, 183 (1997) .

RIKEN Accel. Prog. Rep. 33 (2000)

Damping of Mult.iphonon Giant Resonances
N. Dinh Dang, K. Tanabe, and A. Arima[Multiphonon giant resonance, Strength function , Anharmonicity]
Recent observation of the double giant dipole resonances (DGDR) in relativistic heavy-ion reactions
via the Coulomb excitation 1) and pion-induced chargeexchange reactions 2) has sparked intensive studies andhot debates on the issue of multiphonon excitations.
The harmonic picture represents the n-phonon giant
resonance as a result of folding n independent single
resonances. The energy of an n-phonon dipole resonance would be exactly n times of the energy of the giant dipole resonance (GDR), each with a width rGDR.
Hence , the width of the n-phonon GDR would be equal
to nfGDR. If a Gaussian distribution is used insteadof a Lorentzian to approximate the GDR, the widthof the n-independent-phonon GDR becomes fofGDR.
The data, however, have shown that there is a significant deviation from the harmonic picture of the
DGDR. In a closed-shell nucleus e08Pb) this deviation is much smaller than that in an open-shell one
36 Xe) . In 208Pb, the cross section of the DGDR in
the Coulomb excitation is about 33% larger than thevalue obtained by folding the cross sections of two independent GDRs (the folding results). In 136Xe, thecross section has been observed (215 ± 32 mb) to bestrongly enhanced about 2-3 times compared to thefolding results (70-87 mb). Since the harmonic picture neglects the coupling between the GDRs, the fundamental question is how large the anharmonicity is,or how strongly the coupling between GDR phonons
makes the description of the multiphonon resonancedeviate from the independent-phonon picture.
In this work, the phonon damping model (PDM)3)
was applied to derive a set of equations that describe the damping of n-phonon giant resonances(n > 1). As examples of the application of thisapproach, the results of numerical calculations forthe double giant resonance (DGDR) (n = 2) andtriple giant dipole resonance (TGDR) (n = 3) in
90Z r , 120Sn and 208Pb are discussed and comparedwith the folding results.
For the DGDR in the
double magic nucleus 208Pb, we found that theseresults are very close to the folding results. In the
open-shell nuclei 90Zr and 120Sn, a clear deviationfrom the folding results was obtained, in agreementwith the experimental trend. The results for the
integrated strength and energy of TGDR are found to
be much closer to the folding results in all three nuclei

20
15

w
x

W

(a) gOZr

triple GDR(b) 120Sn

triple GDR(c) 208 Pb

triple GDR

10

en

5
0
15

w
x

10

w

en

5

0

e

20
15

w
x

W

en

10
5

o

~~-=~~~~~~=-~-L~o 10 20 30 40 50 60 70 80 90
E (MeV)

Fig. 1. Energy-weighted strength functions of the TGDR in
90Z r (a) , 120Sn (b) , and 208Pb (c). The solid curves are
the results obtained within the PDM, while the dashedcurves are the folding results.
(Fig. 1). The TGDR widths in the open-shell nuclei
were found to be larger than the folding results. We
also show that a small deviation of the two-phonon
energy is sufficient to cause a noticeable change in the
DGDR strength compared to the independent-phonon
picture.
References
1) H. Emling: Part. Prog. Nucl. Phys. 33, 629 (1994) ; K.
Boretzky et al.: Phys. Lett. B 384, 30 (1996).
2) S. Mordechai et al.: Phys. Rev. Lett. 61, 531 (1988).
3) N. Dinh Dang and A. Arima: Phys. Rev. Lett. 80, 4145
(1998); Nucl. Phys. A 636 , 443 (1998).

23

RIKEN Accel. Prog. Rep. 33 (2000)

Giant Dipole Resonance in Neutron-Rich Nuclei
within the Phonon Damping Model
N. Dinh Dang, T. Suzuki, and A. Arima[Giant resonances, Pigmy resonance, Exotic nuclei, Thermal and statistical models]
When the binding energy approaches zero, coupling
to the continuum becomes very important. Large gaps
between the proton and neutron binding energies inexotic nuclei lead to a big difference in the neutron
and proton level spacing. As a result, the distribution of the giant dipole resonance (GDR) in exotic nuclei becomes more fragmented. These are some common features of the GDR in exotic nuclei that have
12
10
;;.
Q)

:::2:
'l'

0

s

J

en

(a)

8

6
4
2
0
12
10

;;.
Q)

:::2:
'l'

0

s
--;:.

w

en

8

6
4
2
0
16

;;.

12

(e)

Q)

:::2:

b

8

.".

4

s
w

rn

0
16
;;.

12

(d)

Q)

:::2:

'"b

8

--;:.

4

w

en

5 10 15 20 25 30 35 40 45
Ey (MeV)Fig. 1. CDR strength functions in 40Ca (a), 60Ca (b), 120Sn(c), and 150Sn (d).

24been obtained in a number of theoretical calculations
within the random-phase approximation,l) relativistic
RPA,2) self-consistent Hartree-Fock plus RPA,3) andlarge-scale shell-model calculations. 4) In these calculations, the damping of the GDR has not been explicitly calculated, but the strength distributions were justsmeared out by a Lorentzian with a finite width. The
question concerning the effect of damping of the GDR
on the strength of the pigmy resonance in exotic nuclei
still remains open.
In this work, the damping of the giant dipole resonance (GDR) in neutron-rich unstable nuclei 18, 24 0,
60Ca, and 150Sn was calculated within the phonon
damping model (PDM)5) and compared with those instable isotopes: 160, 40Ca, and 120Sn. The HartreeFock single-particle energies obtained employing the
SGn interaction were used in the calculations. The
PDM parameter for the (particle-hole)-phonon interaction between the levels close to the Fermi surface inexotic nuclei was chosen to simulate the strong coupling between the GDR phonon and the dense incoherent particle-hole configurations. The results of thecalculations show the appearance of a low-lying structure (pigmy resonance) in all neutron-rich nuclei underconsideration. Figure 1 shows the difference between
the GDRs in stable nuclei (40 Ca and 120Sn) and thosein unstable nuclei (60 Ca and 150Sn) obtained within the
PDM. The calculations at nonzero temperature showthat the GDR in a hot medium and heavy neutronrich nuclei exhibits a similar behavior to that of the
hot GDR in stable nuclei. The pigmy resonance issmoothed out with increasing temperature.
References
1) I. Hamamoto, H. Sagawa, and X. Z. Zhang: Phys. Rev.
C 53, 765 (1996); Phys. Rev. C 57, R1064 (1998); P.
G. Reinhard: Nucl. Phys. A 649, 305e (1999).
2) Z. Ma, H. Toki , B. Chen , and N. Van Giai: Prog. Theor.
Phys. 98 , 917 (1997) .
3) E. G. Lanza: Nucl. Phys. A 649, 344c (1999).
4) H. Sagawa and T. Suzuki: Phys. Rev. C 59, 3116 (1999);
T. Suzuki, H. Sagawa, and P. F. Bortignon: Nuel. Phys.
A (2000) , in press.
5) N. Dinh Dang and A. Arima: Phys. Rev. Lett. 80, 4145
(1998); Nuel. Phys. A 636, 443 (1998).

RIKEN Accel. Prog. Rep. 33 (2000)

Local Harmonic Approaches with Approximate Cranking Q,p erators
T. Nakatsukasa, N. R. Walet,*l and G. Do Dang*2[Collective models, Hattree-Fock, Random-phase approximations]
The selection of proper collective variables is an important problem in studying large-amplitude collective
motion. In the usual Constrained Hartree-Fock (CHF)
or Hartree-Fock-Bogoliubov (CHFB) calculations, thecollective subspaces are generated by a small numberof one-body constraint (also called cranking) operators, which are most commonly taken to be of themultipole form (rLYLK). In realistic calculations ofprocesses such as fission, because the number of coordinates used to describe the full nuclear dynamics caneasily become larger than can be dealt with in a satisfactory manner, a method to determine the optimal
combination needs to be devised. Even assuming thatsuch a method exists, there is no a priori reason tolimit oneself to multi pole operators, and the cranking
operators should be determined by the nuclear collective dynamics, itself, from the set of all one-body operators. This is clearly a difficult task, and one would
like to be able to select a small group of operators, andto find the optimal combination of these operators at
each point of the collective surface.
In our past work, we investigated a theory of adiabatic large-amplitude collective motion as a method
to generate self-consistent collective subspaces. 1 ,2) The
key ingredient of the method is the self-consistent determination of the constraint operator; as such, it may
provide an answer to the selection question discussed
above. Using the local-harmonic version of the theory,the local-harmonic approximation (LHA), we have recently embarked on a study of the properties of largeamplitude collective motion in systems with pairing. 2)
We would like to find the collective coordinate,q = q(~), for a classical Hamiltonian in a large configuration space {~a},1

H = 2Ba{37ra7r{3 + V(~).

(1)

In LHA, the collective path (or collective surface formore than one coordinate) is determined by solving
the CHFB problem with a cranking operator which isself-consistently determined by the local random-phaseapproximation (RPA). The usual RPA equation can be
expressed by

V,a, B ,i3 q,{3 = W 2 q,a,(2)where a comma denotes the derivative as

*1

*2

8q
q,a =

8~a'

(3)

We have shown that this RPA equation should be modified as follows, when the state is not a local minimum:-,{3
2
V;a, B q,{3 = W q,a,(4)
where the covariant derivative V;a, is defined by

V;a, = Y:a, - r~, Y:{3,(5)r{3a, = ~~q,a,.

(6)

The mass parameter, Ba{3, is also modified according
to the terms of the second order in momentum. This
modified RPA equation guarantees separation of the
spurious (N ambu-Goldstone) modes.
Since the LHA procedure requires us to solve RPAat each point on the collective path, it will be very
useful if the RPA eigenvectors can be approximatedby taking linear combinations of a small number of
one-body operators. This means that we can restrict
RPA diagonalization to this small space, rather thandeal with the full millions-by-millions RPA matrix. For
the pairing-plus-quadrupole model, we have examined
the possibility of expressing the self-consistent cranking operator in terms of a limited set of one-body operators. It seems to be very difficult to approximate
the normal-mode vectors using elementary one-bodyoperators. This difficulty disappears, however, when
we use a small number of state-dependent one-bodyoperators. This may reflect the importance of the selfconsistent determination of the collective coordinates
for large-amplitude collective motion, because the coordinates now have a state dependence as well. The
best cranking operator that we have found for describing the, vibration is the quadrupole operator, whose
two-quasiparticle matrix elements are weighted with afactor Eiq;. With the self-consistent cranking operators, LHA should provide a significant improvement
over the conventional CHFB calculation based on fixedcranking operators.
References
1) A. Klein, N. R. Walet, and G. Do Dang: Ann. Phys.
208, 90 (1991).
2) T. Nakatsukasa and N. R. Walet: Phys. Rev. C 57, 1192
(1998); Phys. Rev. C 58, 3397 (1998).

Department of Physics, UMIST, UK
Laboratoire de Physique TMorique, Universite de ParisSud, France

25

RIKEN Accel. Prog. Rep. 33 (2000)

Relativistic Tilted Axis Cranking Model and Its Application to
Shears Bands in the A == 80 Mass Region
H. Madokoro, J. Meng, M. Matsuzaki , and S. Yamaji[Relativistic mean field, Tilted axis cranking, Shears bands, 84Rb]
New shears bands in 82 Rb and 84 Rb were discovered
in a recent experiment. I) Many shears bands have been
observed in several mass regions, such as the A rv 200,
130 and 100 regions; this is the first experimental dataobtained in the A rv 80 mass region. Up to now, many
features of these shears bands have been well understood within the framework of Tilted Axis Cranking(TAC),2) by using the pairing+QQ model 3 ) and theshell model. 4) On the other hand, fully microscopic andself-consistent calculations have not been performed.
Therefore, for the first time we have applied the Relativistic Mean Field (RMF) model, which has gratefully
been successful in reproducing many properties of finite nuclei , to such tilted rotation.
For applications to rotating nuclei, the Lagrangian of
the RMF model must be generalized into a uniformly
rotating frame which rotates with constant rotationalfrequency, n. From this generalized Lagrangian, theequations of motion can be derived. This can be donein the same manner as that in the Principal Axis
Cranking (PAC) case. For details, see Ref. 5. The
method used to solve the coupled equations of motion is, again, the same as that in the PAC case. The
nucleon and meson fields are expanded in terms of 3dimensional harmonic-oscillator eigenfunctions.
In the actual calculation, we use a parameterset called NL3.
Here, we show the result for
84Rb as an example. The configuration is fixed to7r(lg 9/ 2)2 v (1g9/2)-3. The contribution to the total angular momentum mainly comes from 2 proton particles
and 3 neutron holes in the 199 / 2 orbital. The calculated quadrupole deformation at n = 0.1 MeV is /32 rv
0.2. This value seems to be slightly too large compared with the typical values observed in the shears
bands in other regions. In our present calculation, thepairing correlation is not taken into account. Notethat including the pairing correlation may reduce thequadrupole deformation. The triaxial deformations arerather small, which can be neglected.
Figures 1 and 2 show how the direction of the total
angular momentum vector changes with an increase of
the rotational frequency in 84Rb. Also shown are thenet contributions from proton particles and neutron
holes individually. From Figs. 1 and 2, we can see thatboth the proton and neutron angular momenta aligntowards the total spin as the rotational frequency increases. The direction of the total angular momentum
does not change very much. We thus observed thatthe shears mechanism does appear in this case. In the

26

20
Q=O.lMeV

15

...::

10

l tot
5

15

20

Fig.!. Composition of the total angular momentum at n
= 0.1 MeV. )rr and )v represent the contribution fromproton particles and neutron holes, respectively. l'tot is
the total angular momentum .

20
Q=0.5MeV

15

...::

10

l tot
5
~

5

10

15

20

Ix

Fig. 2. · Composition of the total angular momentum at n
= 0.5 MeV.

future, we will include a pairing correlation within theframework of the cranked relativistic Hartree Bogoliubov approach.
References
1) H. Schnore et al.: Phys. Rev. Lett. 82, 4408 (1999) .
2) S. Frauendorf, J. Meng, and J. Reif: Proc. Conf. on
Physics from Large ,),-Ray Detector Arrays, Vol. 2, p. 52(1994).
3) S. Frauendorf: Nucl. Phys. A 557, 259c (1993) .
4) S. Frauendorf, J. Reif, and G. Winter: Nucl. Phys. A
601, 41 (1996).
5) H. Madokoro and M. Matsuzaki: Phys. Rev. C 52,
R2934 (1997).

RIKEN Accel. Prog. Rep. 33 (2000),Wobbling ' Motion-in the Multi':'Bands Crossing Regiont
M. Oi , A. Ansari ,* T. Horibata, and N. Onishi[NUCLEAR STRUCTURE; Wobbling motion, Tilted cranking, Band crossing]The back-bending in the A ~ 180 mass region is expected to be caused by multi-bands crossing between
low-K (g- and s-bands) and high-K bands (K7r =8+).1,2) We have analyzed a mechanism for couplingthese bands in terms of a dynamical treatment for nuclear rotations, i.e., the wobbling motion. The wobbling states are produced through the generator coordinate method after angular momentum projection,in which the intrinsic states are constructed through2d-cranked HFB calculations. 3 ,4)We have investigated a mechanism of back-bending
and signature inversion in 1820s, by means of thegenerator coordinate method with angular momentum
projection (GCM after AMP) on the 2d-cranked
HFB states. Using this method, we qualitatively
reproduced the main feature of level structure showing
the signature inversion in the high-K band (seeFig. 1) . We interpret this result from the pointof view of an inter-band interaction between the
low-K and high-K bands.
We have shown thatthe perturbed states have characters of the wobbling

Yrare of the GeM states; 1.16
Yrare of the GeM states; 1;140.008 , . - - - , - - . - -- . - - , - - - - . - - - - , 0.009 ,.--,...-,..-..,---.--.---.---,---,
0.008 1-.. ...... ;.........;..........i ..... .

a.
co

"t:

~
,:;'"
"'6

~

g

0.007

; . ....... ;0.006..; .i ....;........... -I 0.007 1-

0.006 I-

0.005

. .,......... , ...... , ....... ~ . -.i....... i..

j..... ..... ;.

H··i.

,...

c ......

0.005
0.004

0.004
0.003

0.003
· H ···· i;···· ...... ·· -I 0.002

0.002
0.001

0.001

a

· 15

OL-~~~-L~~~~

·10

·5

10

15

-20 -15 ·1 0

-5

0

5

10

15

20

Yrast of the GeM states; 1=16
Yrast of the GeM states; 1;1 4
0.025 , . - - - , - - . - - - . -- , - - - - , - - - , 0.016 .__..--.---r--.----,----,----,---,

f
OJ

0,014

0.02

0,012
0.01 1-"""'" ." .. " ""'.; . ...

0.015

O,OOB

"0
Q)

0.01

~

0.005

(fJ

0.006
0.004
0.002

a

-15

O~~~

-10

-5
0
5
K-quantum number

10

15·20 ·15 ·10__-L~~~~·50
510K-quantum number

15

20

Fig. 2.
Graphs for the overlaps between the GCM
state and the spin-projected intrinsic states: gk ==(w (J, e) Ipi}K Iwit)· The left panels are for the GCM
states before band crossing (I = 14 n), and the rightpanels are for the states after crossing (I = 16 n). The
lower and upper panels show the yrast and first yrare
states, respectively. In each panel, the graphs are separately drawn for each tilt angle: e = 0°, ±7° and ±20°.

GeM Energy spectrum (J='4; n=")·40.5 ,.-----r-----r---=~_.__~-____r_---.__--,·4,.. ..'

Yrast:=! .
lst yrare·· ••_.
2nd yrare _.

'

-41.5

.. ..
'

-42

i

.. B·'· · ..'·
'

-42.5

>-

i

w

13

14

15
Angular momentum

16

17

18

Fig. 1. Energy spectrum calculated through GCM after
AMP. The angular momentum constraint for the intrinsic state is fixed to be J = 14 n. From an analysis of
the generator wave functions, the yrast and the second
yrare bands (.6.1 = 2-bands) are of the low-K characters, while the first yrare band (.6.1 = I-band) is of thehigh-K character. The signature inversion is seen at
the region 1 > 15 n.

motion, that is, dynamical-mode coupling low-K PAR
and high-K TAR states (see Fig. 2).
In termsof this wobbling model, we have discussed an enhancement of back-bending in the A ~ 180 region , in which the typical rotation-alignment issomewhat suppressed by the location of the Fermi level.
We have also shown that the solutions of the HillWheeler equation have a new type of symmetry ("signature" ) in the wobbling model, and that the restoration of the signature through the wobbling motion
is related to coupling between high-K and low-K
states.
References
1) T. Shizuma et al.: Phys. Lett. B 442, 53 (1998).
2) P. M. Walker et al.: Proc. Int. Conf. on the Future of
Nuclear Spectroscopy, Crete (1993).
3) T, Horibata and N. Onishi: Nucl. Phys. A 596, 251(1996).
4) A. Ansari, M. Oi, T. Horibata, and N. Onishi: Nucl.
Phys. A 654, 558 (1999).

Condensed from the article submitted to Phys. Lett. (1999)
Institute of Physics, Doordarshan Marg, India

27

RIKEN Accel. Prog. Rep. 33 (2000)

Relativistic Hartree-BogoliubovApproach for Nuclear Matterwith a Non-Linear Coupling Term
S. Sugimoto, K. Sumiyosh~, and H. Toki
[Relativistic Hartree-Bogoliubov theory, Pairing interaction]
We have developed the new method which can incorporate non-linear coupling terms of mesons into thepairing channel in the relativistic Hartree-Bogoliubov
theory(RHB). RHB theory is an extended version of
the relativistic mean-field theory (RMF),l) which cantreat both the pairing channel and the particle-holechannel self-consistently. We have applied it to nuclear
matter to see the effect of the non-linear coupling termsof mesons on the pairing channel, and found that theseterms reduce the pairing gap, ~, by a few l\IIe V.
Pairing interaction is a well-known residual interaction, which is especially important for open-shell nuclei. In the mean-field theory it is usually implemented
by a BCS-type scheme. In this scheme, because twonucleons which are in the time-conjugate states to eachother constitute a Cooper pair, the ground-state energy of the nuclei are lowered. It is known that BCS
theory works well in the region around the stable line.
However, the BCS scheme cannot properly incorporate the mean field of nuclei in the pairing channel.
The Hartree-Fock-Bogoliubov(HFB) theory can incorporate the mean field of nuclei in the pairing channel in addition to the usual mean-field effect, whichis brought by Hartree-Fock theory. The relativistic
Hartree-Fock-Bogoliubov(RHFB) theory is a relativistic version of the HFB theory, which was first derived
by K ucharek et al. 2) In RHFB theory the pairing interaction is mediated by mesons. We can treat theparticle-hole interaction and the pairing interaction
self-consistently and simultaneously within RHFB theory. Recently, RHFB theory and RHB theory, which
neglects the Fock term, have been applied to nuclear
matter 3 ) and finite nuclei,4) with satisfactory results.
However, by now the non-linear terms of mesons arebeing neglected in the pairing channel. In RMF theory these terms are needed to reproduce the properties of nuclear matter and the finite-nuclei properly.5 ,6)
We can believe that these terms may have some effect on the pairing channel in RHFB and RHB theory.
We have thus extended the RHFB theory to be able
to incorporate non-linear meson coupling terms in thepairing channels. In our framework, meson fields are
expanded around the classical mean field value, which
can reproduce the RMF theory, and the residual terms
mediate the pairing interaction.
For a detailed formulation we are presenting a paper.
In Fig. 1 we show the pairing gap, ~, at the Fermi
momentum, kp, in nuclear matter, calculated by the28-

With NL coupling;" .... - - .....
Without NL coupling ;
..

3

,

;

,:
,,

,,

,,
',,

.
,
.

,,
,

,

2

,,

\,

"

,

,,

,,

.,
,

o
0.0

0.2

0.4

0.6

0 .8

1.0

1.2

kF [fm- I ]Fig. 1. Pairing gap at the Fermi surface tl(kF) as a functionof the density characterized by the Fermi momentum,
kF. The solid line is obtained with the non-linear termof mesons in the pairing channel. The dashed line corresponds a scheme without the non-linear term effect.
RHB theory with the non-linear terms having an effect on the pairing channel. In Fig. 1 we also show
the result without the non-linear coupling term. We
use the TMI parameter set, which has non-linear aand w meson terms. 6) From Fig. 1 we can see that byincluding the non-linear terms the pairing gap is reduced by a few MeV. This is because the masses ofthe mesons increase effectively by the non-linear termsof the mesons. If we use the other parameter set, although the maximum ~(kp) values somewhat change,
all other tendencies are almost the same. Note that in
the calculation we introduce the cut-off parameter inthe pairing channel.
In summary, we extended the RHFB theory to include non-linear meson terms in the pairing channel.
We have applied it to nuclear matter, and have foundthat the non-linear terms reduce the ~ by a few MeV.
In the future we will apply it to finite nuclei.
References
1) B. D. Serot et al.: Adv. Nucl. Phys. 16, 1 (1986); P.
Ring et al.: Prog. Part. Nucl. Phys. 37, 193 (1996).
2) H. Kucharek et al.: Z. Phys. A 339 , 23 (1991).
3) F. B. Guimaraes et al.: Phys. Rev. C 54, 2385 (1996);
M. Matsuzaki: Phys. Rev. C 58 , 3407 (1998).
4) J. Meng et al.: Phys. Rev. Lett. 77, 3963 (1996) ; G. A.
Lalazissis et al.: Phys. Rev. C 60 , 014310 (1999).
5) J. Boguta et al.: Nucl. Phys. A 292 , 413 (1977).
6) Y. Sugahara et al.: Nucl. Phys. A 579 , 557 (1994).

RIKEN Accel. Prog. Rep. 33 (2000)

The r-Process Nucleosynthesis in Supernovae
M. Terasawa, K. Sumiyoshi, T. Kajino, and I. Tanihata[r-Process, Supernova]
All elements up to the region of the iron peak aresynthesized by the charged-particle-induced nuclear reaction in stars. If heavier elements above the ironpeak had been produced by silicon burning or anothercharged-particle-induced fusion reaction, their abundances would drop very steeply with increasing mass.
Actually, the observed solar-system abundance distribution of the heavy elements exhibits a much slower
decrease with mass number and much higher abundances than expected from charged-particle-induced
reactions. On the other hand, heavy elements easily
capture neutrons even at extremely low energy withno coulomb barrier to overcome. Moreover, the abundances of heavy elements have characteristics correlated with neutron captures. The most importantcharacteristic would be seen to be an enhanced stability of nuclei with magic numbers N = 50, 82, and 126
neutrons. We observe six peaks in the solar-systemabundance distribution, three at the number of theneutron magic number, and the other three at a number smaller than the magic number. The abundancesof the nuclear species seem to suggest that two different
types of neutron-capture processes (s-process and rprocess) have participated in the synthesis of the heavy
elements.
For the s-process, neutron capture is slower thanbeta-decay, and closely follows the valley of betastability. Thus, relatively stable nuclei at the magic
number are abundant. The astrophysical site where
the s-process occurrs is He ft.ash of an AGB star. Thishas been confirmed by an observation of 99Tc in S-typestars.
On the contrary, if neutron capture proceeds on a
rapid time sale compared with the beta-decay lifetimes,
the network of reactions is called the r-process, which
occurs in a very strong neutron ft.ux. The r-process follows a path at the extreme neutron-rich side of the valley of stability. Very neutron-rich nuclei also have theproperty of magic nuclei. Thus, magic nuclei are abundant. Once the neutron ft.ux ceases, neutron-rich matter produced evolves quickly by several beta-decays to
the region of stability. We observe the nuclei afterbeta-decay. Then, the nuclei at a smaller number thanthe magic number are abundant. Although many studies have been devoted for clarifying the origin and evolution of those nuclei, the astrophysical site for the rprocess still remains an unresolved mystery. The highneutron density and rapid expansion time scale associated with the r-process suggest core-collapse (type IIor type Ib) supernovae as being the most likely setting

0 .001 r - - . . , - - - - , - - - - - - , - - - - , - - - - , - - , - - - - , - - - - , - - 1
full net small net ... . .

0.0001

.J\

(I)

"
§'"

f\~!

le·05

~

i\/!r,''')

le.()6

le·07

LJ.i:1L..----'--~-1:-7.40::---:-:,60;:---:,-;;80:----;;,200~--;:22~O-~240

60

80

100

120

Mass Number

Fig. 1. Final abundances as a function of the mass number.
The solid line is in the case of including light neutronrich nuclei and the dotted line is that of including only
3-dody reactions.

for explosive nucleosynthesis, though the exact environment within supernovae is unclear . Most of the
focus of recent studies on the r-process has been on
the stellar wind or the atmosphere of a hot neutronstar to is formed as a remnant of collapsing iron coresof massive stars. This is because these models are directly relevant to SN 1987 A, and most of the collapse
models currently being studied are representative of
this progenitor mass, 15-20M0 .
Previous works in the literature have shown that 3body reactions (for example 30:) are most importantto create seed nuclei for the r-process. They ignored
light neutron-rich nuclei (Z < 10). This is because athigh temperature (T) and high density (p) the rateof 3-body reactions is higher than that of other reactions. However, in the r-process environment T varies
from 1 to 0.1 MeV and p from 109 to 10 2 glcc, typically. If T and p drop rapidly, seed nuclei must becontinually created when T and p get low. This implies the importance of no-3-body reactions. In studies of the r-process nucleosynthesis, the r-process could
occur in a low-entropy environment with a short dynamic time scale of the expansion. Thus, we included
light neutron-rich nuclei reactions in our network calculation. The results are shown in Fig. 1. In thiscalculation, we applied a short dynamic expansion
model(Sumiyoshi et al. 1999). Figure 1 shows thatthe light neutron-rich nuclei reactions play an important role in the r-process. We are now determining
what are the most important reactions.

29

References
1) S. E. Woosley, J. R. Wilson, G. J. Mathews, R. D .
Hoffman , and B. S. Meyer: Astrophys. J. 433, 229(1994).

30

2) Y.-Z. Qian, W. C. Haxton, K. Langanke, and P. Vogel:Phys. Rev. C 55, 1533 (1997).
3) K. Sumiyoshi, H. Suzu.ki, K . Otsuki, M. Terasawa, andS. Yamada: in preparation.

RIKEN Accel. Prog. Rep. 33 (2000)

Hydrodynamical Study of Neutrino-Driven Winds as r-Process Sites
K . Sumiyoshi, M. Terasawa, H. Shen,* K. Oyamatsu, H. Toki, H. Suzuki, and S. Yamada[EOS , Supernova, r-Process]The rapid neutron-capture process (r-process) is believed to be the origin of heavy elements in the U niverse. Although supernova explosions are most likely
to be the sites, where and how the r-process can occur in supernovae has not yet been clarified. We havestudied the neutrino-driven wind as an r-process siteby performing hydro dynamical simulations to clarify
whether the r-process nucleosynthesis can occur or
not. 1) We have simulated the hydrodynamics of thesurface layers just above the proto-neutron star, which
is born in a supernova explosion, and have performed rprocess network calculations using the trajectories obtained from the simulations.
We adopted a numerical code for the generalrelativistic, implicit hydrodynamics in sphericalsymmetry.2) The heating and cooling processes due
to neutrinos are added on top of the hydro code. As
for the equation of state (EOS) of dense matter, wehave adopted the table of the relativistic EOS, which
was recently derived for supernova simulations. 3) The
relativistic EOS is derived by the relativistic nuclear
many-body framework , which reproduces the nuclear
matter saturation and the properties of stable and unstable nuclei in the nuclear chart.4) The table covers awide range of density, electron fraction and temperature , which has enabled us to perform supernova simulations.
Figure 1 demonstrates the hydro simulations of theneutrino-driven wind. The surface layers above theproto-neutron star are heated up by neutrinos and

10-3
10-4
OJ

u

c

10-5

ro
"0

c

:J
..0

<t:

10- 6
10-7
10-8

100

150

200

A
Fig. 2. Calculated abundance of the r-process elements asa function of the mass number.

ejected as expanding matter. We have examined thisexpansion, which leads to nucleosynthesis, to judge
whether the r-process is possible from numerical simulations. We found that the expansion time scale isshorter than those in previous analytic studies. A
shorter expansion time scale is favorable for the rprocess, since it leaves a higher neutron-to-seed-nuclei
ratio.
Using the trajectory obtained from the simulations,
we performed the nuclear reaction network calculationsof the r-process. Figure 2 shows the calculated abundance of the r-process elements as a function of themass number. In this case, mass elements up to the
3rd peak (A = 195) are successfully created. We havefound that the r-process indeed occurs in the case of ashort expansion time scale with a massive and compact
neutron star having a high neutrino luminosity.
In summary, we have shown by hydro simulations
that the neutrino-driven wind in supernova explosions
is a promising site for the r-process to create heavy
elements.
References

time [sec]Fig. 1. Trajectories of mass elements in hydrodynamical
simulations displayed as functions of time.
Nankai University, China

1) K. Sumiyoshi, H. Suzuki, K . Otsuki, M. Terasawa, andS. Yamada: astro-ph/9912156, submitted to Publ. Astron. Soc. Jpn.
2) S. Yamada: Astrophys. J. 475, 720 (1997).
3) H. Shen, H. Toki, K. Oyamatsu, and K. Sumiyoshi:
Nucl. Phys. A 637, 435 (1998).
4) D. Hirata, K. Sumiyoshi, I. Tanihata, Y. Sugahara,
T. Tachibana, and H. Toki: Nucl. Phys. A 616, 438c
(1997).

31

RIKEN Accel. Prog. Rep. 33 (2000)

44Ti: Its Effective Decay Rate in Young Supernova Remnants, and
Its Abundance in Cassiopeia At
Y. Mochizuki, K. Takahashi,*l H. T. Janka,*l W. Hillebrandt,*l and R . Diehl*2[Nucleosynthesis, Supernovae]
Radioactive isotopes such as 44Ti probably offer themost direct probe into nucleosynthesis environmentsin the interior of exploding stars, when the associatedI'-ray activities in the explosion remnant are detected
and translated back to the isotopic abundances at thetime of the explosion. In this paper, we assert thatthe procedure may not necessarily be straightforward,
at least in the case of 44Ti, an orbital-electron capture
decay isotope.
The binding energy of the K-shell electrons of 44Ti
was calculated to be 6.6 keY. Hence, it is obvious that
44Ti is fully ionized when it is synthesized in a supernova explosion. After the explosion, the temperature of the ejected material decreases rapidly due toadiabatic cooling as the ejecta freely expands. Consequently, it is expected that the freshly synthesized
nuclei become neutral within about 1000 sec.
There is a possibility that 44Ti re-ionizes, however.
This is due to reverse-shock heating. The reverse shockis produced by high pressure behind the blast-wave
shock interacting with the surrounding circumstellar
medium. The reverse shock goes back into the ejecta
and heats up and ionizes it during the free-expansion
phase on the evolutional course of the supernova remnant.
Using the analytic model of McKee & Truelovel}for young supernova remnants, and assuming the existence of overdense 56 Fe-dominated clumps that also
contain 44Ti, we showed that a high degree of ionization may be caused 'by reverse shock, so that theelectron-capture rate of 44Ti can be significantly reduced from its laboratory value. Note that the decayrate measured in laboratories is for neutral atoms.
The nuclear I'-rays from 44Ti decay have been detected by COMPTEL experiments on the CGRO satellite from Cassiopeia A (Cas A), a nearby supernova
remnant. The I'-ray flux detection has a strong impact, since:we can test the theories of collapse-driven
supernova explosions through conversion of the flux
into the initial abundance of 44Ti at the time of the
explosion, employing the values of the decay rate, thedistance', and the age of Cas A.
In order to estimate the observable consequences of
the reduced,B-decay rates, one has to recall that ,t he

*1

*2

32

Condensed from the article in Astron. Astrophys. 346, 831(1999)
Max-Plank-Institut fUr Astrophysik, Germany
Max-Plank-Institut fur Extraterrestrische Physik, Germany~ 4-<.....,~

-<.I

3

0:
x
Q)

o

2

~
............

0.2

0.4

q

0.6

0.8

Fig. 1. The 44Ti radioactivity observable at time t ("age" inyears) relative to the case that assumes no reduction ofthe ,B-decay rate, as a function of the mass coordinate,q, within the ejecta.

measurable I'-ray activity per (normalized) unit massof the remnant is the product of the current ,B-decayrate and the current abundance, n(t)Aeff(t). Figure 1
illustrates the 44Ti radioactivity observable at time t("age" in years) relative to the case that assumes no
reduction of the ,B-decay rate. In the figure, the abscissa q shows the relative mass coordinate within theejecta.
In conclusion, we found that under certain conditions the ionization of 44Ti and the corresponding delay of its decay can yield up to three times higher
44Ti activity at the present time than predicted on
the grounds of the laboratory decay rate. This effectis large enough to reduce the apparent discrepancies
between the 44Ti production in the explosion inferredfrom the CO MPTEL I'-line measurements and the theoretical predictions from the current supernova nucleosynthesis models. This possibility is, however, subject
to various uncertanities, and particularly to the unknown properties and radial disbribution of the clumps
in the ejecta.
References
1) C. F. McKee and J. K. Truelove: Phys. Rep. 256, 157(1995) .

RIKEN Accel. Prog. Rep. 33 (2000)

A New Parameterization of Polarized Parton Distribution FUnctions
Y. Goto, N. Hayashi, M. Hirai, H. Horikawa, S. Kumano, M. Miyama,
T. Morii, N. Saito, T.-A. Shibata, E. Taniguchi, and T. Yamanishi[RHIC , Spin, Asymmetry, Polarized PDF, Polarized DIS]
We started a collaboration to determine the spin
contents of the parton distribution function (PDF) ina nucleon based on high-energy polarized experimental
data. 1) In this article, we report on our first result ofa world asymmetry data analysis . See Ref. 2 for thedetailed analysis and references therein.
The main sources of the PDF information are inclusive deep-inelastic-scattering (DIS) experiments. For
unpolarized PDF, the Drell-Yan process, the promptphoton process, and the jet-production process are alsoavailable to cover a wider kinematical region.
For the polarized PDF, we have only polarized DIS
data to determine the distribution , although there has
been progress concerning the data precision. Theoretically, there has been much progress, including a nextto-leading order (NLO) calculation. Many groups areanalyzing the polarized DIS data and parameterizing
the polarized PDF. Because the polarized DIS data
are still limited, there are many uncertainties in theanalysis. Conventional analyses show that the quark
contribution to the proton spin (.6.E) is only 20% to
30% of the total spin. To explain other contributions
to the proton spin, we need to know the gluon contribution, !::J.G .
Experimentally, in addition to the DIS data, there
have been several attempts to determine the gluon contribution to the proton spin. Charm production at
DESY-HERMES and CERN-COMPASS, and prompt
photon , heavy ft.avor and jet production in polarized pp
collisions at BNL-RHIC will constrain both the shapeand the first moment of !::J.G.
The parameterized polarized PDF provides predictions for current and future polarized experiments totest their analyses. After new data are obtained, parameterization will be performed by including all of
the new information.
In our model for the parameterization, we require
two natural , conditions: the positivity condition andthe counting rule. Its functional form at the initialscale Q5 is!::J.!i (X , Q6) = AixQi (1 + li XA i )!i(X, Q6)
for i = u v , dv , ij, g (valence u quark, valence d quark,sea quark, and gluon). Functions !i(X , Q6) show
the unpolarized PDFs, !::J.!i(X , Q6) show the polarized
PDFs, and Ai, ai , and Ai are parameters to be determined in the analysis. This form satisfies the counting
rule by requiring it on !i(X, Q5). The positivity condition is required by 1!::J.!i(x, Q6)1 < fi(x, Q6). Here, we
reduce the number of free parameters by assuming the

0.8.. . LO
-

0.6

·

·
0

""<-

0.4

·
0

2

Q =5GeV

2

NLO

El30
E143
EMC
SMC
HERMES

0.2

0

-0.2
0.001

0.01

0.1

x

Fig. 1. Comparison of our calculations with the experimental asymmetry, Al(x, Q2), data for the proton.
The leading-order (LO) and the next-to-Ieading order(NLO) results are shown by the solid and dotted lines,
respecti vely.

SU(3) ft.avor symmetry for the sea quarks.
The physical quantities to be fitted ate the crosssection asymmetry, Al (x, Q2), of the proton , neutron,and deuteron. The polarized PDFs are evolved to the(x,Q 2 ) points where the experimental data were taken
to calculate Al (x, Q2) for a X2 analysis. Figure 1 shows
Al (x, Q2) data for the proton and the fitting result of
our leading-order (LO) and the next-to-Ieading order(NLO) calculation.
In this analysis, we did not apply any theoreticalrequirements to restrict the small-x behavior of the
PDF , e.g. the Regge theory or perturbative QCD.
The amount of quarks carrying the nucleon spin is!::J.E = 0.201 in the LO , and .6.E = 0.051 in the NLO at
Q2 = 1 GeV 2 • Although these results confirm that thequarks carry a small amount of nucleon spin, it should
be noted that our !::J.E in the NLO seems to be considerably smaller than the conventional ' values. The
difference originates mainly from the small-x behaviorof the antiquark distribution. The existing data cannot fix it. In order ,to clarify the situation, we need tohave higher energy facilities.
We also obtained positive values of !::J.G in both LO
and NLO . However it is difficult to determine !::J.G, particularly in the LO. We need to wait for measurementsof .6.G at DESY, CERN and RHIC.
References
1) Y. Goto et al.: RIKEN Accel. Prog. Rep. 30,35 (1997);
31 , 44 (1998); 32, 37 (1999).
2) Y. Goto et al.: RIKEN-AF-NP-342 (1999); to be published.

33

RIKEN Accel. Prog. Rep. 33 (2000). :Large PT At Production In Polarized PP Scattering
K. Ohkuma, K. Sudoh, and T. Morii[pp interaction, Polarized gluon, At production]
The proton spin has been long considered to be givenby the sum of the constituent quark spin in the naive
quark model. However, recent experimental data on
.
.
f
I
p(n)
the polanzed
structure functIOns
0 nuc eons, g1,
have revealed that the amount of the proton spin carried by quarks is very small. 1 ) This has been called
the "proton spin puzzle". Actually, the proton spinis given by the sum of the spin of quarks, gluons andorbital angular momenta among them. To understandthe physical ground of this spin-sum rule, it is very
important to understand the behavior of the polarized
partons in the nucleon. However, knowledge about
the polarized gluon density, b:.g( x), in a nucleon is still
poor, though many processes have been proposed so
far to extract information about them.
Here, to extract the polarized gluon distribution,b:.g(x) , we propose another process, large PT At productions in polarized pp scattering, in anticipation of
the forthcoming RHIC experiment. The At spin isbasically carried by a charm quark, which is produced
by gluon-gluon fusion at the lowest order in this process. Hence, an observation of the spin of the produced
At provides information about polarized gluons in the
proton. To extract information about b:.g(x) , we calculated the spin-dependent differential cross section for
pp --+ At + X at the large-PT region and the spincorrelation asymmetry, ALL, defined byd(]"++ - d(]"+_ + d(]" __ - d(]"_+d(]"++ + d(]"+_ + d(]" __ + d(]"_+_ db:.(]"/dpT

ALL = --~----~-------------­-

da /dpT 'where d(]" +_, for example, denotes the spin-dependent
differential cross section with the positive helicity ofthe target proton and the negative helicity of the
produced At. Those values will be measured by theforthcoming RHIC experiment. To calculate the crosssection and asymmetry, ALL, we took the GS96 2 ) and
GRSV96 3 ) parameterization models for the polarized
gluon distribution function and the GRV95 4 ) model

34

0.35
0.3
0.25
0.2

ALL
0.15
0.1
0.05
0
2

4

6

8

PT

10

12

14

[GeVJ

Fig. 1. Spin correlation asymmetry, ALL, as a function of
PT at VB = 50 Ge V. The solid line and dotted lines
indicate the GS96 and GRSV96 models, respectively.
for the unpolarized one. The GS96 and GRSV96 models can excellently reproduce the polarized structure
function of nucleons, though the polarized gluon distributions for those models are quite different.
We show the numerical result of ALL in Fig. 1. Here,the difference can be seem between the solid and dottedlines corresponding to the GS96 and GRSV96 models,
respectively. As shown in Fig. 1, ALL is sensitive to thepolarized gluon distribution functions. Therefore, thisprocess which we proposed here could provide good information about the distribution of the polarized gluons in a nucleon.
References
1) D. Adeva et al., SMC Collab.: Phys. Lett. B 329, 399(1994); K. Abe et al., E143 Collab.: Phys. Rev. Lett.
14, 354 (1995).
2) T. Gehrmann and W. J. Stirling: Phys. Rev. D 53, 6100
(1996).
3) M. Gliick, E. Reya, M. Stratmann, and W. Vogelsang:
Phys. Rev. D 53, 4775 (1996).
4) M. Gliick, E. Reya, and A. Vogt: Z. Phys. C 61, 433(1995).

RIKEN Accel. Prog. Rep . 33 (2000)

A~ Productions in Polarized ep Reaction

and Polarized Gluons in the Proton
N. 1. Kochelev, T. Morii, and S. Oyama[Polarized gluon, At production, Semi-inclusive reaction]
Over the years, the spin structure of nucleons has
been one of the most challenging topics in nuclear andparticle physics. To understand it deeply, it is very
important to know the polarized gluon distribution .
However, knowledge about the polarized gluon distribution in a nucleon is still poor. To extract such information, we propose to study the process of semiinclusive At production in electron-polarized proton
scattering,e+jJ~ e+A~ +X.

In the naive quark model, the spin of At is equal
to the spin of the c quark. In addition, the c quarkis produced from protons just through gluon fusion in
the lowest order. Therefore, a measurement of the spinof At provides information about the polarized gluon
in the proton. Furthermore, since the process directly
depends on the polarized gluons in the proton, it must
be effective for testing the model of polarized gluons.
By using the typical parameterization models of polarized gluons , GS96 1 ) and GRSV96,2) we calculated thespin-dependent differential cross sections, d~(j-;dydz,
and their 2-spin asymmetry, ALL, between the protonand At on semi-inclusive At productions in electronproton scattering; y and z are dimensionless variables
used in semi-inclusive deep inelastic scattering. The
results are presented in Fig. 1.
In Fig. 1, we can see that the results largely depend on the models of the polarized gluon distribu-

0.3

GS96 A - GRSV96 -----------

0.25

>cr:

0.2

I-

'"

w

~

2

0.15

«

0.1
0.05

o

"

.......... ," . ......

>-

(J)

"

-- . ..................

1
L-~

o

-...... _---------__~__~__~~__~__~__~~__~

0.1

0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
YFig. 1. 2-spin asymmetry, ALL, between the proton and
At. Vs = 50 GeV and z = 0.05.

tions. Therefore, the process proposed here must be
promising for testing the polarized gluon distribution
in the proton, though we need to know the polarizedfragmentation function of the c quark to At decays tomake the numerical results more accurate.
References
1) T. Gehrmann and W. J. Stirling: Phys. Rev. D 53, 6100
(1996) .
2) M. GlUck, E. Reya, M. Stratmann, and W. Vogelsang:
Phys. Rev. D 53, 4775 (1996).

35

RIKEN Accel. Prog. Rep. 33 (2000)

Behavior of Polarized Light Sea-Quarks in a Nucleon
T. Morii and T. Yamanishi[Parton distribution, Sea quark, Structure function, Nucleon spin structure]
Experimental groups of NMC, E866/NuSea andHERMES observed a violation of the flavor symmetry in the unpolarized light flavor sea-quark distributions. Recently, this subject has been a challenging
topic in particle and nuclear physics. In the polarized
case, an important question is whether the symmetry of polarized sea-quarks of ~u and ~d is also violated at an initial Q6 in the nonperturbative region. So
far, several theoretical groups have presented excellent
parameterization models by analyzing high-precision
data of polarized deep inelastic scatterings based on
NLO of QCD. l ) From these analyses, we now have agood understanding of the polarized valence of u and dquarks. However, our understanding of polarized seaquarks and gluons is still very poor.
Here, we propose new formulas 2 ) for extracting
a difference in the polarized light sea-quark density, ~d(x) - ~u(x), from the present polarized
deep-inelastic semi-inclusive data. By using theseformulas together with suitable unpolarized quark
distributions and fragemtation functions, we haveestimated the values of ~d(x) - ~u(x) from the
h±
h±)
± )
data set of (Alp,AId
by SMC, and (h±Alp' A hPHe
3
and (Af:, A;3±He) by HERMES ,4) on the double
spin asymmetries. The result is shown in Fig. 1. To
extract some physics from this result, we parameterized the difference of the light flavor sea-quark
densities as tld(x) - ~u(x) = C xQ{d(x) - u(x)} at
22
Q2 = 4 Ge V , and carried out a X fitting to the result
presented in Fig. 1. The X2 fitting led to C = -3.40
and a = 0.567 for the GRV98(LO) unpolarized
parton distribution. C i= 0 is a remarkable result,suggesting an asymmetry of ~d(x) and ~u(x), as
shown in Fig. 1. It is interesting to note that thenegative value of C is consistent with predictions
from an instanton interaction or the chiral quark
soliton model. 5,6) However , it must be premature toemphasize this result, because the present data have

36

~ 2

,.

I:> 1

<I
I

-

0

(;'

o

,..1

I~

<I ·2

,...;.-

1

t

·3
·4

·5
0 .001

0.010

x

0.100

1.000

Fig. 1. x dependence of tl.d(x, Q2) - tl.u(x, Q2) at Q2 =4 GeV 2. The marks indicated by the open circle, solid
circle and solid square denote the results calculated
from the set of SMC data, HERMES data for charged
hadron productions and HEMRES data for charged
pion productions, respectively. The solid line indicatesthe result ofax2-fit by the parameterization formula
presented in the text.

errors that are too large. We urgently need to havemore high-precision data to confirm this result.
References
1) For examples, E. Leader, A. V. Sidorov, and D. B.
Stamenov: Phys. Rev. D 58, 114028 (1998).
2) T. Morii and T. Yamanishi: Phys. Rev. D 61, 057501(2000).
3) B. Adeva et al.: Phys. Lett. B 420, 180 (1998).
4) A. Simon: HERMES Internal Note 98-054.
5) A. E. Dorokov, N. I. Kochelev, and Yu. A. Zubov: Int.
J. Phys. A 8, 603 (1993); A. E. Dorokov and N. I.
Kochelev: Phys. Lett. B 304, 167 (1993).
6) M. Wakamatsu and T. Kubota: Phys. Rev. D 59,
034020 (1999).

RIKEN Accel. Prog. Rep. 33 (2000)

Color,;" Octet Contribution to the Photoproduction of .1jJ'
K. Sudoh and T. Morii[Color-octet model, NRQCD, Polarized gluon]
Heavy quarkonium productions and decays havebeen traditionaly calculated within the framework of
the color-singlet model based on QCD. However, thepredictions by the color-singlet model were too small to
explain the recent Tevatron and HERA data. 1 ) During
these years, the color-octet model has been discussed
as one of the most promising candidates that can remove such large discrepancies between the theoreticalprediction and the experimental data. A rigorous formulation of the color-octet model has been introduced
based on an effective field theory called nonrelativistic
QCD (NRQCD). 2) The cross section can be systematically calculated by the factorization approach basedon NRQCD. However, the validity of the NRQCD factorization approach has not yet been confirmed withgood accuracy. The discussion still seems to be controversial. It is thus important to test the model in otherprocesses.
In this work, to test the possible color-octet contribution, we propose the following process:i+p-t 'I/J' +X,
at small-PT regions, which might be observed in theforthcoming COMPASS or polarized HERA experiment , where the arrow attached to the particles meansthat these particles are longitudinally polarized. The
process is dominated by the color-octet subprocess,'Y + 9 -t (CC) octet, at small-PT regions, if the color-octetmechanism works. The conventional color-singlet subprocess , 'Y + 9 -t (CC) 8inglet + g, appears only as asecond order of the strong coupling constant, 0: 8 , Furthermore, since the process is dominantly produced inphoton-gluon fusion , the cross section is sensitive tothe gluon density in a proton. We can thus obtain
good information about the polarized gluon distribution functions, if the NRQCD factoriz ation approachis confirmed with good accuracy.
To test the color-octet mechanism and polarized
gluon, we calculated the two-spin asymmetry, ALL , for'I/J' production in the polarized process , which is definedby- [dO'++ - dO'+_ + dO'_ - dO'_+ ]A LL - [dO' ++ + dO' + _ + dO' _ + dO' _ +]dllO'
dAO'8 + dllO'ldO'
dO'§.. + dO'1.
where dO'+_ , for instance, denotes that the helicity ofthe beam particle is positive. and that of the target

proton is negative. If there is only the color-octet contribution, which is the lowest-order process in 0: 8 , theasymmetry of ALL can be given by a product of theratio of gluon densities and that of the color-octet longwhich could be deterdistance parameters , e andmined from other experiments, ase,e

The factor of e / has been extracted from recent analysis of the charmonium hadroproduction data,3) as follows:e8

To calculate ALL, we used the GS96 (set A andB)4) and GRSV96 5 ) parametrizations for the polarized gluon distribution. In the GS96 or GRSV96
parametrization model, which is widely used , the maximum value of llg(x)/g(x) becomes roughly 0.2-0.35.
Hence, if we rely on this value for the ratio of the gluon
distributions , the maximum value of the ratio of the
NRQCD matrix elements should be

ee ;S 5.0,
from the requirement that the ALL should be less than1.
In summary, to investigate possible color-octet contribution, we calculated the two-spin asymmetry, ALL,for various values of8/8, and found that ALL becomesquite large in the regions Js = 10-20 GeV. Therefore,
we can sufficiently test the color-octet model in thisprocess. In addition, the measurement of ALL is very
effective to severely constrain the value of the NRQCD
matrix elements, though it depends on the polarized
gluon distribution, llg(x) .
References
1) CDF Collab. , F . Abe et al.: Phys. Rev. Lett. 69, 3704
(1992); Phys. Rev. Lett. 71, 2537 (1993); HI Collab.,
C. Adloff et al.: Eur. Phys . J. C 10, 373 (1999).
2) G. T. Bodwin et al.: Phys . Rev. D 51, 1125 (1995).
3) M. Beneke et al.: Phys. Rev. D 54, 2005 (1996); A. K .
Leibovich et al.: Phys. Rev. D 56, 4412 (1997).
4) T. Gehrmann et al.: Phys. Rev. D 53, 6100 (1996).
5) M. GlUck et al.: Phys. Rev. D 53, 4775 (1996).

.37

RIKEN Accel. Prog. Rep. 33 (2000)

Antiquark Flavor Asymmetry In Polarized Drell-Yan Processes
S. Kumano and M. Miyama[Parton distribution, Structure function]
Light antiquark flavor asymmetry has been an exciting topic after the discovery of the Gottfried-sumrule violation in 1991.1) It is important for testing anonperturbative aspect of the nucleon structure. In
light of the RHIC-Spin project, the polarized version
should become an interesting topic in the near future.
In this report, we discuss the relation between the ratioof the proton-deuteron (pd) Drell-Yan cross section to
the proton-proton (pp) one, D,.(T)<Jpd/2D,. (T)<JPP == Rpd,
and the flavor asymmetry in polarized light-antiquark
distributions. 2 )A formalism of the polarized proton-deuteron DrellYan process is given in Ref. 3. The difference between the spin-parallel and anti-parallel cross sections
is given by
D,. (T) <Jpd <X

L e~ xwhere D,.(T) = D,. or D,.T, depending on the longitudinal or transverse case, and !::J.(T)qad and !::J.(T)~ arethe quark and antiquark distributions in the deuteron.
The pp cross sections are given in the same way simply by replacing the parton distributions in Eq. (1):qd ---7 q and Qd ---7 q.
We investigated the cross-section ratio, Rpd. If thevalence-quark distributions satisfy D,.(T)Uv(X ---7 1) »D,.(T)dv(x ---7 1) , the ratio Rpd at large XF = Xl - X2
becomes= ~ [1 + D,.(T) ~(X2) 1
D,.(T)U(X2)

.

(2)

X2->0

Thef(~_fore,

if the distribution !::J.(T) U is the same as
the ratio is simply given by one. The above
equation suggests that the deviation from one should
be related to the D,.(T)U/ D,.(T)d asymmetry. In this way,
we have found that the data in the large-x F region areespecially useful for ~easuring the flavor asymmetry
ratio , D,.(T)U(X)/ D,.(T)d(x). On the other hand , if another limit, X F ---7 -1, is taken, the ratio becomes
D,.(T)d,Rpd(XF ---7 -1) =~ [1 + D,.(T)d(xt) 1
2

4 D,.(T)u(xd

c2"
"0

= 1.0

fq

= 1.3

0.5

IS = 50 GeV

MJ.lJ.l= 5 GeV
O·~~~~~~~~~~~~~~~-1-0.8 -0.6 -0.4 -0.2

0

0.2

0.4

0.6

0.8

XF
cross-section ratio , Rpd_
The solid and dashed curves
are for the longitudinally and transversely polarizedcases, respectively.
1.

Drell-Van. (3)Next, we show expected pd/pp ratios numerically.
The leading-order (LO) results are shown in Fig. 1 at
yS = 50 GeV and M J-LJ-L = 5 Ge V. The Drell-Yan crosssection ratio , Rpd, was calculated in the longitudinallyand transversely polarized cases; the results are indicated by the solid and dashed curves, respectively. For
the transversity, we assumed that they are equal to
the longitudinal distributions at Q2 = 1 Ge V 2 . They
are evolved to those at Q2 = M2J-LJ-L with the LO evolution equations. 4 ) The flavor asymmetry ratio was taken
to be Tij == D,.(T)U/ D,.(T)d = 0.7, 1.0, or 1.3 at Q2 =1 GeV 2 . As shown in Fig. 1, the flavor asymmetryeffects are conspicuous especially at large x F.
We have shown that the difference between the pp
and pd cross sections is valuable for finding the flavor
asymmetry. It is especially important that we pointout the possibility of measuring the flavor asymmetry
in the transversity distributions, because it cannot befound in W-production processes and inclusive lepton
scattering due to the chiral-odd property. We hopethat the experimental possibilities are seriously considered at FNAL, HERA, RHIC , and JHF.

Xl->O

If the antiquark distributions are flavor symmetric, theratio is given by Rpd = 5/8 = 0.625. Comparing theabove equation with Eq. (2), we find a difference of afactor of 4. This suggests that the ratio Rpd for XF ---7
-1 should not be as sensitive as that in the large-x F
region, although the D,.(T)U/ D,.(T)d asymmetry could
also be found in this region.
38

fq

D.(T) (Jpd/2D.(T) (Jpp.

(1)

2

f(j = 0.7

Fig.
[D,.(T)qa(Xt) D,.(T )Q:(X2)aRpd(XF ---7 1)

l.5r--------------~

References
1) S. Kumano: Phys. Rep. 303, 183 (1998).
2) S. Kumano and M. Miyama: hep-ph/9909432.
3) S. Hino and S. Kumano: Phys. Rev. D 59, 094026(1999); Phys. Rev. D 60, 054018 (1999).
4) M. Hirai , S. Kumano, and M. Miyama: Comput. Phys.
Commun. 108, 38 (1998); Comput. Phys. Commun.
Ill, 150 (1998).

RIKEN Accel. Prog. Rep. 33 (2000)

Nucleon-Structure Functions In the NJL Model t
H. Mineo,* W. Bentz, and K. Yazaki[Quark distribution function, Faddeev approach, NJL model]
Quark light-cone momentum distributions in the
nucleon are calculated in a relativistic 3-body approach to the NJL modeI 1 ,2) by using a simple "static
approximation" 3) for the Faddeev kernel, which reduces the original three-body problem to an effective
two-body problem.
A method based on a straightforward Feynmandiagram evaluation is presented which automaticallysatisfies the number and momentum sum rules, evenin the regularized theory. In order to assess the sensitivity to the regularization scheme, two schemes which
can be formulated in terms of light-cone variables
are discussed. One is due to Lepage and Brodsky,4)which introduces a cut-off in the two-body invariant
masses. The other is due to Lenz et ai.,5) which introduces a cut-off only in the transverse directions,while renormalizing the longitudinal direction. A
comparison of the resulting distributions with theempirical ones after the Q2-evolution 6 ) indicatesthat the latter scheme is superior, which is similar tothe situation found previously for the distribution in
the pion. 7 )The effects of the (composite) pion cloud are taken
into account in a convolution approach, and the violation of the Gottfried sum rule is discussed. The
effects slightly improve the agreement with the empirical distributions and enhance the violation, but are
not sufficient to explain the observed asymmetry of
the sea-quark distributions.
References
1) Y. Nambu and G. Jona-Lasinio: Phys. Rev. 122, 345(1960); Phys. Rev. 124, 246 (1961).
2) T. Hatsuda and T. Kunihiro: Phys. Rep. 241, 221(1994).
3) N. Ishii, W. Bentz,
Yazaki: Nuel. Phys. A 518,
617 (1995).
4) G. P. Lepage and S. J. Brodsky: Phys. Rev. D 22, 2157
(1980).
5) F. Lenz, K. Ohta, M. Thies, and K. Yazaki: to be published.
6) S. Kumano: Phys. Rep. 303, 183 (1998); M. Miyama
and S. Kumano: Camp. Phys. Commun. 94,185 (1996).
7) W. Bentz, T. Hama, T. Matsuki, and K. Yazaki: Nuel.
Phys. A 651, 143 (1999).

ancrx.

Condensed from the article in Phys. Rev. C 60, 065201(1999)
Department of Physics, Graduate School of Science, University of Tokyo

39

RIKEN Accel. Prog. Rep. 33 (2000)

UA(l) Symmetry Breaking and Eta Prime Meson In
the Bethe-Salpeter Approach
K. Naito, K. Yoshida,* Y. Nemoto, M. Oka,* and M. Takizawa[Chiral symmetry, U A (1) anomaly, Relativistic bound state1
Chiral symmetry and its spontaneous breakdown
are key concepts in hadron physics. Eight pseudoscalar mesons (7r, K, TJ) have been identified as the
Nambu-Goldstone bosons. Further, UA (l) symmety
breaking is also important , because it affects the chiral symmetry breaking and the properies of the ninth
pseudo-scalar meson, TJ' . Since the chiral symmetry is closely related to the Lorenz covariance, nonrelativistic approaches, such as the harmonic-oscillator
model, are not suitable. We use the fully relativistic Bethe-Salpeter approach and concentrate on thepseudo-scaler mesons : 7r, TJ and TJ'.
We employ the improved ladder gluon exchangeinteraction 1,2) and the 't Hooft-type three-flavor determinant interaction,-(Ie)5 {det[1j}(l - 15)1/;] + det[1j}(l + 15)1/;]} ,

mqR

m sR

Ie

MTJ

f~'

f~'

MeV MeV GeV- 1 MeV MeV MeV
0
0
0
0
0
0
0
0
5
5
5
5

0
0
0
0
100
100
100
100
100
100
100
100

0.0
1.6
2.0
2.4
0 .0
1.6
2.0
2.4
0 .0
1.6
2.0
2.4

0
0
194
0
350
0
634
0
723 - 101
731 -99764 - 881020 - 41723 -101
732 -98
777 -8611060 -36

(}TJ

deg

86
87
88
94
72
76
88
118
72

0
0
0
0
-54.7
-52.5
-45 .0-19.2-54.7
77 -51.8
90 -43.7
122 -16.4

M[MeV]

1000(1)

with the Gaussian form factor. The former reproduces
the asymptotic behavior of the quark propagator andthe latter brings a U(l)A symmetry breaking. The
quark full propagator is obtained by the SchwingerDyson (SD) equation shown in Fig. 1. The bound state
is obtained by the Bethe-Salpeter (BS) equation shownin Fig. 2. These coupled equations respect the chiralsymmetry and its spontaneous symmetry breaking.
The results are given in Table 1 and Fig. 3. We
choose the model parameters to bring out the strong
chiral symmetry breaking by the gluon exchange interaction mainly. The scale parameter is fixed at
AQCD = 600 MeV. This value is somewhat larger than
the standard value. This is because the lack of theinfrared enhancement of the gluon propagator we employed. In our approach, the BS amplitude is obtained

Fig. 1. SD equation.

Table 1. The 1J'-meson solutions of the BS equation.

900
800

0.8

1.6

1

2.4

lG [GeV- ]Fig. 3. Ie dependence of the mass of the 1J' meson with
mqR = 0 and msR = 100 MeV.

as a solution of the BS equation. Its flavor structure
depends on both the relative and total momenta of
the quark and anti-quark. We thus define the mixing angle from the decay constants, f8 and fo. In
the SU(3) symmetry limit , no flavor mixing occurs.
On the other hand , in the broken SU(3) case with
Ie = 0, TJ and TJ' are in ideally mixed states, i.e. ,811 , = arctan( -)2) = -54.7. The mixing angles, 811
and 811 " increase as Ie becomes strong. Physically,
the mixing angle for the TJ' meson, 811 " is more than
5/3-times the calculated mixing angle for the TJ meson.
This means that the momentum dependence of the flavor structures is not very small. In Fig. 3, the effectof the mixing of the u, d quark component seems to be
negligible, and the TJ' meson mass grows rapidly fromIe rv 2.0 GeV- 1 .
References

Fig. 2. BS equation.
Department of Physics, Tokyo Institute of Technology

401) K. Aoki, M. Bando, T. Kugo, M. G. Mitchard, and H.
Nakatani: Prog. Theor. Phys. 84, 683 (1990).
2) K. Naito, K. Yoshida, Y. Nemoto, M. Oka, and M.
Takizawa: Phys . Rev. C 59 , 1095 (1999).

RIKEN Accel. Prog. Rep. 33 (2000)

Final Countdown to RHIC Spin Program
H. En'yo, 1. Alekseev,*l T. Awes ,*2 M. Bai,*3 B. Bassalleck,*4 S. Bathe,*5 A. Bazilevsky, M. L. Brooks,*6
D. Bucher,*5 H. Buesching,*5 G. Bunce, V. Cianciolo,*2 A. Deshpande,*7 J. Doskow ,*8 S. Eilerts,*4
D. E. Fields,*4 Y. Goto, H. Hamagaki, N. Hayashi , H. Huang,*3 V. Hughes ,*7 T. Ichihara, K . Imai,
M. Ippolitov,*9 M. Ishihara, V. Kanavets ,*l D. M. Lee,*6 E. Kistenev,*3 L. Kotchenda,*lo K . Kurita,
K. Kwiatkowski ,*8 B. Lewis ,*4 Z. Li, B. Lozowski,*8 Y. Makdisi ,*3 Y. Mao, H.-O. Meyer,*8 V . Mexner,*5
J. Murata, M. Nakamura,*3 S. Pate,*11 T. Peitzman,*5 U. von Poblotzki,*5 K. Pope,*12 B. Przewoski,*8
K. Read ,*2,*8 T. Rinkel,*8 T. Roser,*3 A. Rusek,*3 N. Saito, T. Sakuma,*13 H. D. Sato, S. Sawada,
T .-A. Shibata, B. Smith,*4 W. Sondheim,*6 S. Sorenson,*12 M. Sugioka, D. Svirida,*1 M. Syphers,*3
A. Taketani, E. Taniguchi, T . L. Thomas ,*4 W . Tian,*2,*14 J. Tojo, H. Torii, D. Underwood,*15
C. Velissaris, *11 Y. Watanabe , S. White,*3 D. Wolfe,*4 K. Yamamoto ,*16 S. Yokkaichi, and L. Zhu[pp interaction, Struture function , Spin, Asymmetry, Polarized beam]

The relativistic heavy-ion collider (RHIC) will undergo its first collision in the year 2000. The RIKEN
collaboration of this international project has resulted
in strong enhancements to the collider, one of whichis the upgrade of the collider for the acceleration ofpolarized protons and another is the upgrade of the
PHENIX detector for the study of spin physics. The
RHIC has become the machine with which to explore"The creation of quark gluon plasma" which has been adream of physicists for over 20 years, as well as to solve"The spin puzzle of the nucleon" which relates to thefundamentals of quantum chromo dynamics (QCD).
The superspectrometer, PHENIX, which we areworking on, will play an important role in exploring such physics at RHIC . The collaboration includes
41 institutes and about 400 physicists and engineers.
The spectrometer consists of two arms for electron
and photon detection and another two for muon detection (see the figure below) . The second muon arm
was added to increase the spin physics capability of
PHENIX. These probes (leptons and photons) are essential for the investigation of the state of nuclear matter in heavy-ion collisions, and also for the detectionof possible spin carriers (gluons and antiquarks) to reconstruct the missing spin in a nucleon from individual constituents of a nucleon. The polarized proton
collider will enable us , for the first time, to directly
Institute of Theoretical and Experimental Physics, Russia
Oak Ridge National Laboratory, USA.3 Brookhaven National Laboratory, USA• 4 Department of Physics and Astronomy, University of New
Mexico, USA.5 University of Muenster, Germany.6 Los Alamos National Laboratory, USA.7 Department of Physics, Yale University, USA.8 Indiana University Cyclotron Facility, USA.9 Kurchatov Institute, Russia* 10 Interphysica, Russia.11 New Mexico State University, USA.12 University of Tennessee, USA. 13 Tokyo Institute of Technology.14 CIAE China.15 Argo~ne National Laboratory, USA.16 Department of Physics, Kyoto University·01.2

measure those spin carriers which remain unidentified
in former experiments using polarized lepton scattering.
In 1999 we passed a very important milestone withthe onset of RHIC operation with the successful storage of beam particles in the rings. The development of
the RHIC polarimeter is one of our major contributions
this year to the spin acceleration project at RHIC. Our
recent work has established a novel technique using
proton-carbon nuclear interference for the beam polarization measurements. I} The RHIC polarimeter design
is now in progress based on this method.
The successful completion of the muon identifier construction, which was carried out in Japan and theUSA,2,3) is now followed by efforts to make the detector
operational in the collision hall. 4) Since May 1999 wehave been contributing to the muon tracking-chamber
construction,5) another of the key detectors in themuon arms to be installed in the summer of 2000. The
quality assurance of the produced chambers is the oneof our major responsibilities.
For the detections of electromagnetic probes it isessential to understand the calorimeter response forhigh-energy particles. A test experiment was carried out at CERN in 19986) and the analysis is essentially finalized. 7) The outcome is very promising
for the direct "y and the W --+ e + l/ measurements
which are the key channels of the spin program. The
measured energy resolution of the calorimeter wasd(J / E = 1.9% + 8.2%/ VB with a linearity better than
2% up to the energy of 80 GeV .
The new project of constructing a computing complex containing 300 Linux-based PCs at Wako was begun in 1999,8) and is the key project in the analyses of the data. The goal of the project is to reach
10 k SPECint95 by the end of 2001. Even in the
preliminary stages of development in 1999, the simulation works have progressed significantly owing tothis new computing project. A possible new probe,
the coincidence signal of electron and muon, to detectgluon polarization was recently studied with the sim-

41

Fig. 1. The PHENIX detector. Two magnets with a flowerpot shape on the left- and right-hand sides
are the muon magnets (the left one is fabricated in Kobe, Japan). Adjacent to these, one can see
the panels of the muon identifiers. The central magnet and the frames of the central arms are seenat the center, pending the installation of the detectors for electrons and photons. [Photograph by
R. Stoutenburgh (BNL) 1

ulation, and proved to be sensitive to the gluon-gluon
scattering which produces a heavy quark pair with anexcellent signal-to- background ratio. 9 ) Progress is has
also been made in the muon identification and muontracking software 10 ) through the full simulation of thedetector response in the muon arms.
The final countdown to the first collision has begun.
Although a lot of work remains to be accomplished bythen, we enjoy marching towards the promised land of
spin physics (Fig. 1).
References
1) J. Tojo et al.: RIKEN Accel. Prog. Rep. 33,170 (2000).
2) K. Kurita et al.: RIKEN Accel. Prog. Rep. 32, 48

42(1999) .
3) A. Taketani et al.: RIKEN Accel. Prog. Rep. 32, 50(1999) .
4) A. Taketani et al.: RIKEN Accel. Prog. Rep. 33, 166(2000) .
5) J. Murata et al.: RIKEN Accel. Prog. Rep. 33, 165(2000).
6) Y. Goto et al.: RIKEN Accel. Prog. Rep. 32,47 (1999).
7) H. Torii et al.: RIKEN Accel. Prog. Rep. 33, 168 (2000).
8) T. Ichihara et al.: RIKEN Accel. Prog. Rep. 33, 172(2000).
9) H. D. Sato et al.: RIKEN Accel. Prog. Rep. 33, 44(2000).
10) Y . Mao et al.: RIKEN Accel. Prog. Rep. 33, 46 (2000).

RIKEN Accel. Prog. Rep. 33 (2000)

Measurement of the Charged Pion Asymmetry andBeam Polarization in AGS E925
N. Hayashi, C. Allgower,*1 M. Bai,*2 V. Baturine,*3 N. Belikov,*4 G. Bunce,*2 A. Derevschikov,*4 H. En'yo,
V. Ghazikhanian,*5 Y. Goto, M. Grosse Perdekamp, T. Ichihara, G. Igo,*5 T. Kasprzyk,*4 Y. Kondo,*6
K. Krueger,*1 H. Huang,*2 S.-Y. Lee,*7 Y. Matulenko,*4 Y. Makdisi,*2 Y. Nakada, M. Nakamura,*6
L. Nogach,*4 S. Nurushev,*4 N. Saito, H. Sakai, H. Sato, A. Taketani, A. Ogawa,*3 M. Okamura,
A. Pavlinov,*4 T. Roser,*2 H. Spinka,*1 M. Syphers,*2 S. Trentalange,*5 D. Underwood,*1
A. Vasiliev,*4 T. Wakasa, C. Whitten,*5 K. Yako, A. Yokosawa,*1 and 1. Zhu[RHIC, AGS, Spin, Asymmetry, Polarized beam, Polarimeter]
We have measured the inclusive charged pion asymmetry at the large-x F and high-PT region for 22-Ge V / ctransversely polarized protons scattered from carbon
or liquid-hydrogen targets. 1) This phenomenon has
been considered in relation to such phenomena as hyperon polarization from unpolarized beams and theproton spin crisis. The mechanism may be studied via
inclusive hadron production in polarized proton interactions.
The experiments were performed in November, 1997,
with a carbon target and in March, 1999, with a hydrogen target. This paper presents the results of the
carbon target; an analysis of hydrogen data using thesame procedure is under way.
The polarized proton beam was extracted from the
BNL AGS and it's polarization, P , was measured by
PP elastic scattering with a CH 2 target. In 1997 thepolarization P was determined to be P = 0.271 ±0.059(stat.) ± 0.028(syst.). A detailed description
can be found in a previous report. 2)
Inclusive measurements were carried out using an independent set of counters (BLl-4, BRl-4, FLA(B) andFRA(B)) for the elastic arm (see Fig. 1). Pion triggers
from a 4.0-cm thick carbon target were defined as the
combination of three counter hits (Sl, S2 and S3) andthree out of four hodoscopes (Hl-4). The spectrometer magnet gave a transverse momentum kick, PT, of
about 1 GeV / c. Its magnetic field was reversed periodically to accept both positive and negative pions.
From the position information in each hodoscope, theparticle momentum as well as Feynman's XF and PT
were extracted. A threshold-type Cerenkov counter
filled with about 2 bar of CO 2 was used to separate
pions from other hadrons.
The asymme~ry, AN, of inclusive pions was measured as a function of x Fusing."
Nl - NT
AN = P[Nl + NT _ 2NB]'(1)
Argonne National Laboratory, USA
Brookhaven National Laboratory, USA*3 Pennsylvania State University, USA*4 Institute of High Energy Physics, Russia*5 ' UCLA , USA*6 Kyoto University*7 Indiana University, USA

DFRA
MAGNET . ... . ........................... -

DFLA

DFRB
DFLB

Fig. 1. Schematic drawing of the E925 setup.

0 .50

a)

!

f

z

<

J/
r-- t .~ .~ .~................
__b)!
...... / '

0.25

I

- - - - - -!l - -x .I.. IL _

0.00

~

-0.25

I

1f+

0 1f-

Ii P

~

--

r-·-~-ot-0.50 L..--...J....-l_-'-----'-_-'----l
.2
.3
.4
.5
.6
.7
.8.2

c---

t

1f+

0 1f

-

.3

.4

.5

.6

~.

.7

).
.8

Fig. 2. Inclusive asymmetry, AN , measured as a functionof XF at a) 22 GeV Ie and b) ,200 GeV Ie.

where Nl (NT) is the normalized number of produced
particles going to the right when the polarization of
the beam is pointing up (down). N B is the normalized
number of estimated background events.
The obtained value of AN is shown in Fig. 2 a).
Here, they are compared with the results from experiment FNAL-E704 (Fig. 2 b)) (200 GeV Ie polarized
proton beam on a hydrogen target). 3) It should be
noted that the asymmetry is large and the x F dependence similar to the E704 results in the large-x F region,
despite the large difference in the beam momenta andproduction targets. This feature could be exploited asa high-energy proton beam polarimeter for accelerators, such as RHIC or HERA.

*1*2

References
1) K. Krueger et al.: Phys. Lett. B 459, 412 (1999).
2) N. Hayashi et al.: RIKEN . Accel.Prog. ,Rep .. 32, 46(1999).
3) D. L. Adams et al.: Phys. Lett. B 264, 462 (1991).

43

RIKEN Accel. Prog. Rep. 33 (2000)

Sensitivities of the Gluon Polarization Measurement ·at PHENIX
A. Bazilevsky, H. En'yo, Y. Goto, N. Hayashi, K. Imai, K. Kurita, Y. Mao, N. Saito,
H. D. Sato, T . Sakuma, T.-A. Shibata, and A. Taketani[RHIC, PHENIX, Spin, Asymmetry, Gluon polarization]
Polarized deep inelastic scattering experiments showthat the fraction of the quark polarization in the proton is only about 30% of the proton spin. The remaining fraction needs to be explained by other sources.
We plan to directly measure the gluon polarizationin the proton at PHENIX using RHIC polarizedproton collisions. This will be carried out by utilizing gluon+quark and gluon+gluon reactions. At
PHENIX, we have two kinds of detector systems todetect many channels of physics signals from these reactions. Two Muon Arms detect muons in the forward
pseudo-rapidity region, 1.2 < 1171 < 2.4. Two Central Arms detect photons, hadrons, and electrons in
the central pseudo-rapidity region, 1171 < 0.35. Each ofthese channels covers different kinematical range complementally. The range of the momentum fraction of
the gluon in the proton, x g , extends from 0.005 to 0.3
totally.
The open and bound-state heavy-flavor production are to be identified by detecting lepton(s) using the Muon Arms and the Central Arms. Since
these reactions are dominated by the gluon fusion process at RHIC energy, a measurement of the doublelongitudinal spin asymmetry, ALL, is sensitive to thegluon polarization, b,.G(x)/G(x), in the proton. We
show three channels used to probe the heavy-flavor
production: di-muon, high-PT single electron, andelectron-muon pair. We have estimated the ratios ofthe signal and background events, and have investigated the sensitivities to the gluon polarization measurement in each channel.
Prompt photons and nOs are detected in the Central
Arms. The prompt photon production is theoreticallya clean channel, because it is dominated by the gluon
Compton process. By measuring ALL, we can determine the gluon polarization by using knowledge of thequark polarization from the polarized deep-inelasticscattering experiments and the calculable asymmetryof the gluon Compton process. A measurement of nO
serves both as a background estimation of a prompt
photon measurement, and as a measurement of thegluon polarization by itself. .
We studied the sensitivities of our measurements using the PYTHIA event generator and the GRV-94LO
parton distribution function for PP collisions. To evaluate ALL, three models of the polarized parton distribution function (GS-A, GS-B, and GS-C) with different
gluon polarization are used. I)
Table 1 summarizes the estimated statistical errors

44

Table 1. Summary of the estimated statistical errors andpredicted values of the ALL and the Xg range to becovered by each channel. The statistical errors show theabsolute values for 10% luminosity 32pb- 1 for channels
indicated by,·) and full luminosity 320pb- 1 for otherchannels.

ALL

ProbesALL Predictions

Xg

Errors

GS-A

GS-B

GS-C

Range

J/'I/J -7 J1-J1-

0.006

0.01

0.01

0.002

0.005 - 0.01

cC -+ eX0.001*)

-0.02

-0.01

-0.0003

0.005 - 0.2

cC -+ eJ.tX

0.006

-0.05

-0.02

-0.0001

0.005 - 0.2

bb -+ eJ.tX

0.006

0.01

0.01

-0.0004

0.01 - 0.3

prompt I

0.006

0.05

0.03

0.001

0.1 - 0.3

?To

0.001*)

0.02

0.01

0.00010.05 - 0.3

and predicted values of the ALL and the Xg range to becovered by each channel. We encountered systematic
errors from a background subtraction procedure andbeam-polarization and -luminosity measurements.
We can clearly identify J l'ljJs by reconstructing theinvariant mass of di-muons with a mass resolution of
100 Me V I e2 . We also plan to measure the polarizationof J I'I/J to investigate its production mechanism. We
have a large yield of single electrons with PT > 1 Ge V I efrom open charm quarks and have good sensitivity with
only 10% of the full luminosity to distinguish the threemodels. We can perform this measurement in the firstyear of the RHIC polarized-proton run (2000-). We
can reduce the major background from nO Dalitz decays and 'Y conversions effectively by detecting charged
tracks. An electron-muon pair is also a useful probe
for open heavy-flavor production because of the low
background event rate. The background from hadrons
can be estimated and subtracted by comparing likesign and unlike-sign pairs.
We can detect prompt photons in the PT range ofmore than 10 GeV Ie using a background-reduction
technique, like an isolation cut. For a nO measurement,
we have a large yield at Pr > 5 Ge V I e. Identificationof nOs can be achieved by mass reconstruction of 2 photons with a small background in this Pr range. The

measurement can be performed fr6m 2000.
In summary, we can start the gluon polarization measurement from the first year of the RHIC
polarized-proton run with many feasible channels.

References
1) T. Sakuma et al.: RIKEN Accel. Prog. Rep. 32, 45(1999); Y. Goto et al.: RIKEN Accel. Prog .. Rep. 31,
54 (1998) and references therein.

45

RIKEN Accel. Prog. Rep. 33 (2000)

Performance of the PHENIX Muon Reconstruction Software
Y. Mao, M. L. Brooks,*l N. Hayashi, K. Kurita, J. Murata, K. Pope,*2 K. Read,*2 N. Saito, H. Sato,
S. Sorenson, *2 and A. Taketani[Reconstruction efficiency, Road finding , Track finding]
We have been developing and testing offline softwareto reconstruct muon events for the PHENIX experiment. The integrated muon offline software has been
established, and has been used for various studies, suchas Mock Data ChaUenge(MDC)l) and a study of thebeam pipe shielding for south muon arm. Single-muon
events were simulated and reconstructed to check thereconstruction efficiency of the software; single-pion
events were simulated and passed to the whole analysis chain to see the hadron rejection capability as well.
The performance of the software to analyze data inhigh multiplicity was also investigated by mixing J /'I!
signal events with central Au-Au background events.
The complete data-simulation procedure is as follows: Generate events with a event generator, for example a PYTHIA event generator; pass the events to
PHENIX Integrated Simulation Application (PISA) tosimulate the detector response; convert the PISA output to PHENIX Raw Data Format (PRDF); reconstruct the PRDF events and save them as Data Summary Tape (DST). The PHENIX muon detector comprises two arms with a tracking part (MuTR) and an
identification part (MuID) in each arm. The reconstruction of an event can be briefly described as: (1)find the clusters in each gap of the MuID; (2) findroads in the MuID based on the clusters; (3) pass thefound roads to MuTr track finding; (4) apply a particleidentification algorithm with such information as themomentum and the depth in MuID of a found track.
We improved our road-finding algorithm2) during a
study for beam shielding for the south muon arm. A
new version of the road finder was optimized in order tosatisfy the following requirements: a higher reconstruction efficiency and a smaller number of ghost roads
by allowing a smaller cluster size and a larger searchwindow and implementing a share-hit method to drop
ghost roads. It is possible to study specific physics bysetting the control parameters; for example, one canchoose a narrow search window and a deeper depth if
a high-momentum muon is interesting. One can also
use a looser cut for p-p and a tighter cut for the AuAu collision to drop ghost roads for the multiplicity ismuch less in the former case.
We analized 3000 single muon events and 30000 single pion events to check the muon software performance. The muons and/or pions were launched fromthe collision point with an emission angle of 135 0 ± 20

and an azumithal angle of 155 0 • The results had, as
shown in Table 1, a road-finding efficiency of about
99% and a track-finding efficiency of about 96-98% formuons in 2.5-5.0 GeV /c momentum region, while thepion-reduction rate was about 3.1 x 10- 3 in the same
momentum region. The efficiency loss was only a few
precent after applying muon identification.
To check the performance in high multiplicity, we
analized 2000 J /'I! mixed with Au-Au central events.
Figure 1 shows the mass spectrum of the mixed events.
The J /'11 resonance was clearly seen , even mixed withsuch strong background, the multiplicity being about
3000/event in a muon arm. The signal/noise ratio wasabout 15 : 1 in the J /'11 mass region. The number ofreconstructed J /'I! muon pairs in Fig. 1 was consistent
with the numbers in Table 1 after considering the efficiency loss due to t he chamber framework of MuTRand the absorber of MuID.
As a result from our evaluation work as well as from
our MDC1 and MDC2, we have confirmed that themuon offline software is in good shape, and is satisfactory for our current requirement. Some more refinements are necessary in the muon-identification module
Table l. The performance of muon software.

MomentumRoad
TrackfinderfinderGeV/cMuon reconstruction efficiency
2.5
99.2%
95.7%
3.0
99.7%
96.5%
5.0
99.9%
98.2%
Pions reduction rate
2.5
3.5 x 10- 3 2.5 X 10- 3
3.0
5.1 X 10- 3 3.9 X 10- 3
5.0
8.5 X 10- 3 5.8 X 10- 3*2

46

Physics Division, LANL, USA
Physics Department , University of Tennessee, USA

98.7%
99.8%
99.9%
2.2 X 10- 3
3.2 X 10- 3
3.8 X 10- 3

120

100 -

80

60

40

20

0.5

·01

Identification

1.5

2
2.5
3
3.5
Dimuon Invariant Mass (GeV)

4.5

Fig. l. The reconstructed dimuon mass spectrum.

to reject more hadrons and in the ghost track drop
module to throwaway more ghost tracks while keeping a relatively high muon reconstruction efficiency.

Shimane.
2) Y. Mao: http://www.phenix.bnl.gov /phenix/WWW /publish/mao/roadfinder / algorithm/

References
1) H. Sato et al.: Japan Physics Society Meet., 1999 Fall,

47

RIKEN Accel. Prog. Rep. 33 (2000)

Precise Measurement of the Muon Lifetime
S. N. Nakamura, D. Tomono,*l Y. Matsuda, K. Ishida, T. Matsuzaki, 1. Watanabe,
K. Nagamine, M. Iwasaki, S. Sakamoto , and G. Mason*2[Standard model, Fermi coupling constant, Muon lifetime]
The Fermi coupling constant (G F) is one of the mostbasic parameters of the standard model. The standard
model requires at least three electroweak parametersfrom the experimental measurements; usually Q (thefine structure constant), M z (the mass of Z) and G F
are used. The uncertainty of Q, Mz and G F are, respectively, 0.045 ppm, 77 ppm and 17 ppm;l) thus, theM z uncertainty dominated until now. However, therecent preliminary LEP results yield an uncertainty ofthe Z mass of 20 ppm or less;2) the situation is changing.
The muon lifetime is directly associated with G F
by the muon lifetime formula. 3 ) The input uncertaintyof G F is dominated by the muon lifetime (TJ.L) uncertainty (PDG average 18 ppm). The uncertainty of the
2-loop electroweak calculation (10-15 ppm) has also
been limiting the accuracy of the theoretical application with G F defined by the muon lifetime formula in
the standard model. However, a precise 2-loop electroweak calculation was recently carried out 4 ) with anaccuracy of better than 1 ppm; thus, the accuracy of
G F is now limited by the uncertainty of the experimentally measured muon lifetime.
The last J.L+ lifetime measurements ( rv 30 ppm accuracy) were performed more than 10 years ago at
TRIUMF5) and Saclay,6) and no improvement has
been made so far (Fig. 1). These experiments observed
one muon decay in an observation time window to
avoid any pileup detection of positrons which distorts
the muon decay-time spectrum. With this method, because the data-acquisition rate is simply limited by the

60,-8Accuracy of Mz
103

:>,
()

cD
s...
;J
()

10 2

()

Fig. 2. Setup of the f..L+ lifetime experiment placed at theport 2 beamline of the RIKEN-RAL Muon Facility. One
set of the MWPCs for positron detection can be seen in
front of the target, and the other set is hidden by thetarget and the helium bag.
width of the time window, there exists a practical accuracy limit with a realistic beamtime. It is essential todevelop a multi-decay per one time window method formore accurate muon lifetime measurements. We designed a new experimental setup 7) (Fig. 2) and started
to observe 109 -10 10 muon decays at the RIKEN-RAL
Muon Facility. We used a holmium plate as a muon
stopping target to minimize the effect of the muon polarization. The target was placed in a helium bag to reduce the number of the muons stopped around the target. Multiwire proportional chambers (MWPC) wereused as a positron timing and tracking device to realize
a fine segmentation which reduces the pileup effect. A
clock system with GPS (global positioning system) was
newly developed to achieve very good differential andintegral linearity. We will finish the first-stage dataacquisition (rv5 x 10 9 muon decays = 10-20 ppm) by
the end of 1999; a preliminary analysis of the acquired
data is now in progress.

<t:
Q)

.5
.....,

10 1 f - - -- [-oo-p- Q-E-D -co- r-re-c -t io- n - -- - - - - " ----1

2

2

::3

Year
Fig. 1. History of the f..L+ lifetime accuracy. The accuracyof the Z mass is also plotted as a reference.
*1 Department of Physics, Tokyo Institute of Technology
Department of Physics and Astronomy, University of Victoria, Canada*2

48

References
1) C. Caso et al.: Review of Particle Physics, European
Physical Journal C 3 , 1 (1998).
2) The LEP Collaborations: CERN-PPE/96-183 (1996).
3) W. J. Marciano and A. Sirlin: Phys. Rev. Lett. 61, 1815
(1988).
4) T . van Rrmbergen and R. G. Stuart: hep-ph/9904240(1999).
5) K. L. Giovanetti et al.: Phys. Rev. D 29, 343 (1984).
6) G. Bardin: Phys. Lett. B 137, 135 (1984).
7) S. N. Nakamura et al.: RIKEN Rev., No. 20, p. 58(1999); RIKEN Accel. Prog. Rep. 32, 173 (1999).

RIKEN Accel. Prog. Rep. 33 (2000)

Measurement of the Ortho-Para Effect in Muon-Catalyzed
dd-Fusion
A. Toyoda, K. Ishida, K. Shimomura, Y. Matsuda, W. Higemoto, S. N. Nakamura,
T. Matsuzaki, and K. Nagamine[Keyword J.LCF, Ortho-para effect]
This measurement will provide a new test of oneof the most important theories in muon-catalyzed
fusion (J.LCF) , namely the resonant formation of amuonic molecule. It will also provide a critical teston the puzzling "solid state" effect in J.LCF.
The muon acts as a catalyst in the fusion process
through forming a ddJ.L muonic molecule. Here , resonant formation of ddJ.L, dJ.L + D2 -+ [(ddJ.L) dee] plays
an important role. Because of the finite muon lifetime(2.2 J.Lsec) , the ddJ.L formation rate is quite importantin achieving a high fusion yield . By artificially changing the initial molecular state, we expect to increase
the formation rate, and thus enhance the overall fusion
cycling rate. 80 far, there have been three parameters

8000

i

i

!

7000

6000

j

,

.. ';.

.. :..

-

,

,
5000

~~. ,
."

~\

' .

;!"

3000

~\.
:;: · l:-

2000

' 000

used to change the D2 state: (1) the temperature, (2)the phase, and (3) the density. This experiment aims
to control the fourth parameter, namely the rotational
state, which can be achieved by changing the ortho
and para ratio of the deuterium.
Furthermore, some theories predicted that the ddJ.L
formation rate decreases rapidly with reducing thetemperature below 20 K, although the experiments
measured no formation rate change below 20 K. 1 ,2)At present , there are several possible explanations. 3- 5)
The para deuterium plays an essential role in the current explanations for this discrepancy. Our measurement will test these mechanisms by reducing the paraconcentration.
In the experiment, we measured fusion protons,
J.Le-decay electrons, and various muonic X-rays. We
formed a solid deuterium target in a vacuum so as tominimize the material between the target and the proton detector. 6 ) For fusion proton detection, we use apair of silicon surface barrier (8SB) detectors. The
3 MeV proton passes the first SSB detector for ~E(25 J.Lmt) and stops in the second one for E-~E(150 J1mt).
The experiment is being carried out at the RIKENRAL Muon Facility in the UK. Figure 1 shows a scatter: .

~i?~ '1..

o 0

'000

2000

3000

,.:

8000

"

'.

..

"(
5000

.

4000

..... \.........
.. · .. f .. · ....
.... ·1.. ·· ..

'/:.

'j

.~'.

.

i

~:7

i'"
o

~ .~~ il~~
II

j

.

I

j

j

i

.
,

...

:}l·,

'000

•

r~ n

r.

2000

8000

6000

i

~A

3000

5000

i

7000

6000

4 000

•.

10

'.

;......';..

'.

II

....

!

"'"

!

i

, 000

2000

3 000

4000

f~:~~

I

5000

6000

7000

8000

SSBl(keV) vs SSB2(keV)".

,.........-.. -.. ... ..

"Fig. 1. Scatter plots for the proton detectors. The top
figure is for a normal deuterium target and the bottom
figure is for an empty target. The horizontal axis is forthe energy deposited in the first SSB (in ke V) and thevertical is for the second SSB.

500

1000

1500

2000

2500

3000

Timing (nsee)
Fig. 2. Fitting result of the fusion proton time spectrum.

49

plot of the two SSB detector's output pulse height.
The fusion protons are clearly seen in the region
around ADC1(~E) = 0.6 MeV and ADC2(E-~E)= 2.4 MeV. The ~E-E particle-identification method
greatly suppressed the background noise, such as byscattered muons and J.Le-decay electrons to achievea sufficiently high SIN ratio( rv5) of fusion protons;
nevertheless, we placed the proton detectors nearto the muon beam. Figure 2 shows a typical fusion
proton time spectrum with fast and slow components. This spectrum also reflects the double-pulsed
muon beam structure of the ISIS synchrotron. The
dotted line corresponds to the background level,
which was estimated from the data without thedeuterium target.
It is theoretically predictedthat the slow component is less dependent on theortho-para state of deuterium than the fast component; therefore, we compared 33% para(normal)
data, 5% para data, and 0.8% para data by observing

50

the fusion proton yield from the fast component. The
detected fusion protons with a fast component normalized by detected electrons from J.L-e decay in the
deuterium target was 6.4(13) x 10- 3 for normal deuterium , 5.6(16) x 10- 3 for the 5% para case, and
5.8(24) x 10- 3 for the 0.8% para case. We are planning
further experiments under more sophisticated conditions to improve the statistics.
References
1) D. L. Demin et al.: Hyperfine Interact . 101/102 , 13(1996).
2) P . E. Knowles et al. : Hyperfine Interact. 101/102, 21(1996) .
3) L. I. Menshikov et al. : Hyperfine Interact. 101/102 ,207 (1996).
4) A. Adamczak: Hyperfine Interact. 101/102 , 113(1996) .
5) G. L. Gurin et al.: Hyperfine Interact. 118 , 147 (1999) .
6) P. Strasser et al. : Phys. Lett. B 368, 32 (1996).

RIKEN Accel. Prog. Rep. 33 (2000)

Study of Muon Catalyzed Fusion in Solid D-T Mixtures
N. Kawamura, K. Nagamine, T. Matsuzaki, K. Ishida, S. N. Nakamura, Y. Matsuda, S. Sakamoto, M. Tanase,
M. K ato, K. Kurosawa , H. Sugai, K. Kudo,*1 N. Takeda,*1 and G . H. Eaton*2[Muon catalyzed fusion]
Through the muon catalyzed fusion (J-lCF) studies
at the RIKEN-RAL Muon Facility since 1995, we haveobtained t he muon cycling rate (A c) in solid/liquid
deuterium and tritium (D-T) mixtures with various
tritium concentration (Ct ) .1 )According to Vesman's mechanism, which is basedon resonant dtJ-l formation through a two-body collision, i.e. tJ-l + D2 ~ [(dtJ-l )dee] , Ac was expected as constant to the D-T mixture density. In order to remove
any trivial density dependence, Ac is already normalized by the target density. However, Jones et al. foundan unexpected density dependence 2) (Fig. 1). Our dataalso showed such a tendency,l) and they were comparable to data at above 100 K , although they were obt ained at much lower temperatures, 20 K (liquid) and
16 K (solid). On the other hand, a theoretical calculation based on Vesman's mechanism indicated a steep
decrease of Ac with the temperature decreasing below
about 100 K.3 )Menshikov and Ponomarev introduced the idea of
three-body collision 4 ); tJ-l + D2 + D 2' ~ [(dtJ-l)dee] +D 2' , where the third particle, D 2' , absorbs any excess energy in dtJ-l formation. This explains the highmolecular-formation rate at low temperature; also, thedensity dependence is explained by the contribution

..--.
I

rn

150

3

~

-<

Q)

~

100

1-0
QlJ

.S
U
>,
()

50

~

o
;j
:::g
oL-~~~~-L~~~

0 .0

0 .5

__~L-~~~~-L~~
1.0

1.5

Density ¢ (in unit of liq. hydrogen density)

Fig. 1. Density dependence of the muon cycling rate. The
liquid and solid data are shown around </> = 1.2- 1.3 (circle) and </> = 1.4-1.5 (cross), respectively. The reference
data are taken from the following articles: "S . E. Joneset al., Phys. Rev . Lett. 56, 588 (1986)" (LAMPF),
and "W. H. Breunlich et al., Phys. Rev. Lett. 58, 329(1987)" (PSI).
*1*2

Electrotechnical Laboratory (ETL)
Rutherford-Appleton Laboratory (RAL) , UK.--, 140
I

rn

3120

QlJ

.S

80

U>,
()

C

60

0

~

::.s

40
5

10

15

20

Temperature at sensor [K]Fig. 2. Observed temperature dependence of the muon
cycling rate.

of D 2'. FUkushima takes into account the effect ofphonons in a solid , which play the role of a third
particle. 5 ) However, still, no theory can provide a quantitative understanding of the unexpected high Ac at
low temperature. Observing the temperature dependence of Ac can supply new important information to
the theory of dtJ-l formation.
In order to investigate this problem, we started a
J-lCF study in a cryo-solid from 16 K to 5 K, and a
preliminary analysis was performed . . Figure 2 shows
the temperature dependence of Ac. For each Ct,
Ac decreases by about 15% with decreasing temperature. This can be explained by a decrease of the dtJ-lmolecule formation rate in collision between (tJ-l)F=O
and D2 (A~:O ,D2): 420 J-lS - 1 (16 K) ~ 300 J-lS- 1 (5 K),
where F denotes the hyperfine level. However, there
is a slight possibility that the change of a different parameter, such as the muon transfer rate from (dJ-l) Is to(tJ-lhs (Adt) , would cause a decrease of Ac. Byanalyzin} the Ct dependence of Ac , Ac can be dissolved into
Adt:O,D2 and Adt terms. In the coming experiment, we
will use a high-Ct target and determine the cause of
the decrease of Ac.
References
1) K. Nagamine et al.: Hyperfine Interact. 119, 273(1999).
2) S. E. Jones et al.: Phys. Rev. Lett. 56, 588 (1986) .
3) M. P. Faifman et al.: Phys. Lett. B 265, 201 (1991).
4) L. I. Menshikov and L. I. Ponomarev: Phys. Lett . B
167, 141 (1986).
5) K. Fukushima: Phys. Rev. A 48, 4130 (1993).

51

RIKEN Accel. Prog. Rep. 33 (2000)

Electron Scattering at MUSES jRIBF
T. Suda, K. Maruyama, and 1. Tanihata[Electron scattering, Charge form factor, Unstable nuclei]
The working group for the electron-nucleus (eA) collider of MUSES has been working to design an electron
spectrometer. The main efforts have so far been paid
to clarify the necessary performances which an electron spectrometer must have for measuring the elastic
electron scattering cross section from unstable nuclei.
As is well known, the charge form factor of a nucleus
is deduced from the elastic electron-scattering crosssection. The charge distributions, such as radii andshapes, of many unstable nuclei will be determined byelastic electron scattering at MUSES. Simulations haveshown that the charge radii can be determined for unstable nuclei whose luminosities (L) are greater than
10 25 cm - 2 S -1, and that the shape of the charge distribution will be studied for L 2: 10 27 cm- 2 S-l. Many
unstable nuclei, whose life time is longer than about
1 minute, are expected to be studied at MUSES.
To determine the shape of the charge distribution in
unstable nuc;1ei, the charge form factor must be measured over a wide momentum transfer (qNR) range by
the elastic electron scattering. Here, qN R is defined in
the nucleus-rest (NR) frame. Since the elastic crosssection changes rapidly as a function of qN R , it is important to determine qN R with high precision. In addition, a good energy-transfer resolution, !:1w N R, is also
necessary to identify the elastic-scattering process.
We set our goal concerning the charge form factor
measurements at MUSES as follows:(1) qNR range: qNR = 100-400 MeV Ie(2) qN R resolution: !:1qN RI qN R rv 10- 3(3) WNR resolution: !:1wNR::; 1 MeV
The difficulties to design an electron spectrometerto carry out such measurements are related to thelimited luminosities for unstable nuclei. Because theconventional electron spectrometers which hasve good
momentum resolution (typically 10- 4 ) but a small
solid angle (rv 30 msr) , can not be our solution, alarge-acceptance spectrometer must be necessarily employed.
The performances that such a large acceptance electron spectrometer must have can be summarized asfollows:(1) High momentum resolution: !:1plp:::; 10- 3(2) Accurate determination of the scattering angle:!:1B rv 10- 3 rad.

52

Here, let us discuss an optimum electron beam energy (Ee) for the charge form-factor measurements at
MUSES. From the point of view of luminosity, a higher
Ee is favorable. Higher energy is also better to suppress any multiple scattering effects of electrons in thematerials of the spectrometer, such as trackers. In fact,
suppressing the multiple-scattering effect is a key toachieving good momentum and angular resolution for
scattered electrons.
On the other hand, the minimum electron scattering angle, corresponding to qNR = 100 MeV Ie, becomes large for lower Ee. For example, they are 12,
8 and 6° for electron-beam energies of Ee = 500, 750
and 1000 MeV, respectively, which are almost independent of the mass number , A , and the energy of nuclear
beam. A lower Ee frees us from serious interference
between the spectrometer and the MUSES rings.
Simulations assuming a large acceptance magnetic
spectrometer with tracking devices have shown thatthe optimum electron beam energy will be in the rangeof Ee = 500-750 MeV, and that the necessary performances of an electron spectrometer for this energy
range are:(1) coverage of a polar angle of B = 8- 40°(2) coverage of an azimuthal angle of ¢ = 27r(3) field integral greater than 2 Tm
(4) total thickness of material, X ::::; 0.3% of radiation length
Currently, two types of magnetic spectrometers arebeing intensively discussed. They are spectrometerswith a solenoid- and toroidal-magnetic field. Detailed
simulations including various effects, such as beamemittance, and multiple scattering, are now under way.
In addition to the simulation, the detection of recoiled nuclei in the storage ring to identify the elastic
scattering is also being discussed simultaneously withthe design group of MUSES.
In summary, the eA working group has been focusing on designing an electron spectrometer, which will
be used for elastic electron-scattering experiments at
MUSES to determine the charge distribution of many
unstable nuclei. The performances required of thespectrometer have been clarified, and detailed simula-·
tions for two types of large-acceptance magnetic spectrometers are in progress.

RIKEN Accel. Prog. Rep. 33 (2000).

y~Measurement of the Polarization Transfer Coefficients, K ij ,for d-p Elastic Scattering at Ed ~ 270 MeV
H. Kato , H. Sakai, A. Tamii, T. Ohnishi, K. Sekiguchi, K. Yakou, S. Fukusaka, S. Sakoda, M. Hatano,
Y. Maeda, N. Sakamoto, T. Uesaka, Y. Satou, K. S. Itoh, H. Okamura, K. Suda, and T. Wakasa

Measurements of the cross sections as well as thevector- and tensor-analyzing powers for deuteronproton (d-p) elastic scattering at 270 Me V have beenreported by Sakamoto et al. 1 ) and Sekiguchi.2) The results are interesting because the observables are sensitive to the effect of the three-nucleon force (3NF).3 4)
The differential cross sections are in excellent agreement with calculations including 3NF by Wit ala etal. 3 ) Although the vector-analyzing powers are also ingood agreement, that at the tensor-analyzing powers
is rather poor.
As new research on 3NF, we measured the polarization transfer coefficients (Ki~ , K~~ , Ki~ ) and the ind uced polarization (Pyl) for d-p elastic scattering at
270 MeV. The measurement was performed using thespectrometer SMART and polarized deuteron beams.
First, polarized deuterons were bombarded onto apolyethylene (CH 2) target. Secondly, the emitted protons were scattered by a car bon target at the second
focal plane of SMART. Finally, the scattered protons
were detected by a focal-plane polarimeter DPOL, bywhich the polarizations of the emitted protons were
measured.
The relation between the polarizations and the observables can be represented by
1

dO'

dO'o (

Pyl dO = dO

3

y'

2

y'

Pyl + 2PyKy + '3PxzKx z

where x , y and z are the coordinates of the incident
deuterons; x' , y' and z' are those of the emitted protons ; and ~ means the differential cross section with
unpolarized beams.
The results of the measurement are ploted in Fig. 1.
by the solid circles with statistical errors. The solid
curves are theoretical predictions with 3NF and thedashed curves are those without 3NF. Both predictions
were calculated by Wit ala et al. 3 ) The horizontal axis(() em) is defined as the angle between the incident andK Y' zz
0.50
0.25
0 .25
0 .00 t-="----"......-----jJ-------'''-l

0.00

-0.25
-0.25
-0 .50-O.tlO

50

100

150

CD-Bonn(3NF)- - CD-Bonn50

8 o .m . [deg]

100

150

8 o.m . [deg]KY' zz
0.4

0.50
0.2
0.25
0.00
- 0.2
-0.25
-0.4

50

100

8 o .m . [deg]

150

50

100 '

150

8 o.m. [deg]Fig. 1. K~~, Kt~ , K~: and Pyl for the d-p elastic scatteringat Ed = 270 Me V. The solid circles are the experimental
results . The dashed curves are theoretical predictionsof the Faddeev calculation using the N N CD-Bonn potent ial without 3NF. The solid curves are those of acalculation which included the effect of 3NF.

outgoing deuterons in the center-of-mass system.
As a result, K~~ and Ki~ are rather consistent withthe predictions with 3NF. However, Ki~ is rather consistent with the predictions without 3NF.
It cannot be concluded from only this experiment
whether the effect of 3NF was observed or not. Clear
evidence may be obtained by an additional study atmore forward angles, where the discrepancy between
those with and without 3NF is much larger.
References
1)
2)
3)
4)

N. Sakamoto et al.: Phys. Lett. B 367, 60 (1996).
K. Sekiguchi: Master thesis , University of Tokyo (1999).
H. Witala et al.: Phys. Rev. Lett. 81, 1183 (1998).
S. Nemoto et al.: Phys. Rev. C 58, 2599 (1998).

53

RIKEN Accel. Prog. Rep. 33 (2000)

Measurement .of the Cross Sections and Vector and Tensor Analyzing
Powers for d-p Elastic Scattering at Ed = 270 MeV
K. Sekiguchi, H. Sakai, N. Sakamoto, H. Okamura, A. Tamii, T. Uesaka, Y. Satou, T. Ohnishi, T. Wakasa,
K. Yakou, S. Fukusaka, S. Sakoda, K. Suda, H. Kato, Y. Maeda, K. S. Itoh, and T. Niizeki
NUCLEAR REACTIONS, IH(d~ d), Ed = 270 MeV measured: a(fJ), Ay(fJ), Ayy(fJ), Axx(fJ),][ Axz(fJ)A study of the nucleon-deuteron system has madesubstantial progress both experimentally and theoretically. We have shown in Ref. 1 that there is a discrepancy in the cross section minimum between thedata and the Faddeev calculations without the three
nucleon force (3NF) at an intermediate energy. It wasrecently shown that this discrepancy can be explainedby 3NF. 2 ,3)We have made precise measurements of the crosssections and vector and tensor analyzing powers ford-p elastic scattering at Ed = 270 MeV. The angular range was fJ c . m . = 10°-180°. A CH 2 target with athickness of 46.7 mg/cm 2 was bombarded by a polarized deuteron beam, and either scattered deuterons or
protons were momentum analyzed by the spectrograph
SMART and detected at the focal plane, depending on
the scattering angle.
The experimental results are shown with solid circles
in Figs. 1 and 2. The errors are only statistical ones.
The open circles are the measurement by Sakamoto
et at. 1) Since the two independent measurements provide almost the same values in the overlapping region,

-0.2

50

100

8 o.m . [deg]

150

50

100

150

8 o .m . [deg]Fig. 1. A y , A yy , A xx , Axz for the d-p elastic scattering at
E~ab = 270 MeV. The solid circles are the results of thisexperiment and the open squares are those of Ref. 1.
The solid curves and dashed curves are the Faddeev
calculations with and without 3NF, respectively. CD
BONN potential is taken as N N interactions. Coulomb
force is not included. The dotted curves are the Faddeev
calculations without 3NF. The Argonne V14 potential isused as N N interactions.

54

10.0

0.5

0.1 L-l..-'---'--'--.1--L......'--'---'--1-.L.-'---'--'--.1-..L.......I--I
o
50
100

8 o.m . [deg]Fig. 2. The cross section for the d-p elastic scattering at
E~ab = 270 Me V. The solid circles are the results of thisexperiment and the open squares are those of Ref. 1.
The solid dashed and dotted curves are the same as
Fig. 1.

the systematic errors seem to be small. The dashedand solid curves in Figs. 1 and 2 are results of the calculations with and without 3NF by Witala et at. 2 ,4)
The CD BONN potentialS) is taken as N N interactions. Note that the Coulomb interaction is not included. The dotted curves are the Faddeev calculations without 3NF in which the Argonne V14 6 ) potential is used. 1) For the cross sections, the calculation
with 3NF shows an excellent fit almost over all angles.
Thus, the discrepancy in the cross section minimum
is indeed reproduced by including 3NF. The observed
vector analyzing power, A y , is also in good agreementwith the calculations with 3NF. However, none of thecalculations shows superiority in describing the tensor
analyzing powers (Ayy, Axx and Au). It should be
noted that the agreement is deteriorated when 3NF is
included. These results indicate that there seems to be
ambiguity of the spin-dependent parts of 3NF as well
as N N interactions.
References
1) N. Sakamoto et al.: Phys. Lett. B 367,60 (1996).
2) H. Witala et al.: Phys. Rev. Lett. 81, 1183 (1998).
3) S. Nemoto et al.: Phys. Rev. C 58, 2599 (1998).
4) H. Kamada: private communications.
5) R. Machleidt et al.: Phys. Rev. C 53, R1483 (1996).
6) R. B. Wiringa et al.: Phys. Rev. C 29, 1207 (1984).

RIKEN Accel. Prog. Rep. 33 (2000)'The 3He( 1, p )4He 'Reaction at Intermediate Energies
T. Uesaka, H. Sakai, H. Okamura, A. Tamii, Y. Satou, T. Ohnishi, K. Sekiguchi, K. Yako, S. Sakoda,
N. Sakamoto, T. Wakasa, K. Itoh, and K. Suda

[3He(d,p)4He , Ed = 140, 200, and 270 MeV, Measured analyzing powers]
The high-momentum component of the deuteronwave function provides a unique opportunity to reveal
the short-range behavior of the nucleon-nucleon (NN)interaction. 1 ,2) Especially, the D-state wave function,
which arises from the existence of the tensor component in NN interaction, manifests its importancein the short-range (r < 1 fm) or high-momentum(k > 1 fm- 1 ) region.
The 3 He( d~ p) 4 He reaction can be an effective probe
to the deuteron D-state wave function because of its
strong spin-selectivity. 3) We measured, for the firsttime at Ed = 270 MeV and Blab = 4° , the polarization correlation coefficient, Gil, which is proportional
to the D-state density within the framework of onenucleon-exchange (ONE) approximation. The resultof Gil was found to be more than a factor of 2 smaller
than the expected value calculated with the ONE approximation and the realistic NN potential model. It
is important to investigate the relevance of the reaction mechanism in order to assess the deuteron D-state
wave function by using the polarization observables.
Following this line, we have recently measured thecross sections and analyzing powers (Ay, A yy , and Axx)
for the 3He(d~p)4He reaction in the angular range ofBl ab = 0°-25° and at Ed = 140, 200, and 270 MeV.
Details of the experimental procedure are described inRef. 4.
In Fig. 1, polarization observables at three energies
are plotted as a function of the scattering angle in the

140 MeV

200MeV

270MeVII
0.0
II~ - 0 .5

0 .5

0.0

a

~N -0.5-1. 0

ONE calculation-1.5 ~'---'--'--'----"--'--'---'--..L--'--L..-'---'-~-'-'--""""""'.............I......J-J'--'-'--'---L-J

o

100

200

300

400

500

600

k [MeV Ie]

Fig. 2. T 20 at zero degree for the 3He(J:p)4He (*), thed+p backward scattering (0), and the deuteron inclusive
breakup (.).
center-of-mass system. The solid lines represent the result of ONE calculations. The vector analyzing power,
which is expected to be identical to zero in the ONE approximation , takes large negative values (-0.3- -0.6)
at forward angles. It is also clearly seen that the magnitude of the tensor-analyzing powers is much smaller
than the prediction of the ONE calculation. Thus, it isconcluded that the ONE approximation is insufficient
to describe the 3He(J:p)4He reaction in these energy
regions.
The tensor-analyzing power, T 20 [= - ~ (Ayy +Axx)], at zero degree is also compared with those forthe d + P backward scattering and the deuteron inclusive breakup data (Fig. 2). The comparison exhibits
the similarity among these reactions. This result indicates that the reaction mechanism of the 3He(d,p)4He
reaction is similar to those of the d + P backward scattering and the deuteron inclusive breakup, and therefore the reaction models which have been developed todescribe the latter reactions can also be applicable tothe 3He(d,p)4He reaction.
References
1) A. P. Kobushkin: Phys. Lett. B 421 , 53 (1998) and-1.0...............~...L...............J........oI...........-'--'-.J'-'--'-'-'-'-~......L.......:
20
30
40 0
10
20
30

_ 1.5t......................J..~........L....~...L......~'-'--'-'-

o

10

20

30 0

10

8 ern [deg]Fig. 1. Polarization observables at Ed = 140, 200, and270 MeV. The solid lines are the result of ONE calculations.

references therein.
2) L. S. Azhgirey et al.: Phys. Lett. B 391, 22 (1997) andreferences therein.
3) T. Uesaka et al.: Phys. Lett. B 467, 199 (1999).
4) T. Uesaka et al.: RIKEN Accel. Prog. Rep. 32, 63(1999).

55

RIKEN Accel. Prog. Rep. 33 (2000)

Measurement of the Deuteron Spin-Flip Probabilities in
the 28Si(d, d!) Reaction at Ed = 270 MeV
Y. Satou, S. Ishida, H. Sakai, H. Okamura, N. Sakamoto, H. Otsu, T. Uesaka, T. Wakasa, T. Nonaka,
T. Ohnishi, G. Yokoyama, K. Sekiguchi, K. Yakou, S. Fukusaka, K. Itoh, T. Ichihara,
T. Niizeki, and K. Hatanaka
NUCLEAR REACTION, 28Si(polarized d, polarized d') Ed = 270 MeV; deuteron sPin-fliP][ probabilities 8 1 and 8 2
Inelastic scattering of polarized deuterons provides
a unique tool to study nuclear spin responses. Since
it is able to transfer spin b..8 = 1 without transferring isospin b..T = 0, the (d, d') reaction is an efficient
probe of isoscalar spin excitations. 1) In addition, being a probe with spin equal to one, the (d, d') reaction provides an opportunity to search for the possible
existence of b..8 = 2 excitations, such as the Double
Gamow-Teller states. 2)
We .report here on a 28Si(d~ d') forward-angle measurement of the cross section and eight polarization
observables (Ay, A yy , pyl, pylyl, K~/, K~~, Ktyl andKt~yl), which aims to understand the isoscalar spinstrengths in 28Si. For the deuteron two spin-flip probabilities (SFPs), 8 1 and 8 2 can be defined corresponding to a change of 1 and 2 units in the componentof the deuteron's spin perpendicular to the scattering
plane. The SFPs, 8 1 and 8 2, are expected to be useful signatures of the b..8 = 1 and b..8 = 2 excitations,
respectively. These are expressed in terms of the polarization observables, as follows:
1

I

I

I

I

8 1 = -9 (4 - Py y - A yy - 2KYyY'
Y )

(1)

1
8 2 = -18 (4 + 2PY y + 2A YY - 9KYy + KYYYY)'
I

I

"

I

(2)

The experiment was carried out using SMART. The
270 Me V vector and tensor polarized deuteron beams
from the RIKEN Ring Cyclotron were focused on a58.1 mg/cm 2-thick natSi target 8Si: 92.2%). The
beam swinger magnet was set at 5° , covering an angular range of 2.5° < Blab < 7.5°. The scattereddeuterons were detected at the focal plane of SMART
with a multiwire drift chamber backed with two plastic scintillation counters. The polarizations of thescattered deuterons were determined by a focal-plane
deuteron polarimeter, DPOL. DPOL had a 2.5 cmthick polyethylene block as the second scatterer, andmade use of the 12C(d,d) and IH(d,pp) reactions
for the vector and tensor polarization measurements,
respectively. 3)
Figure 1 (a) shows the excitation energy (Ex) spectrum of the cross section. A known spin-flip 1+ state at
9.50 MeV is clearly excited as well as non-spin-flip collective states, such as 4+ at 4.62 MeV, 0+ at 4.98 MeV,
2+ at 7.40 MeV and 7.93 MeV and 3- at 6.88 MeV

e

56

r.:I
'tl

c
'tl
.......

930(a) 320

..b
'tl

28 Si

(d.ch at E~=270 MeV.+

81ab=6.0o-7.5°

10

0.2

0.0 I - - - : J < : - - - - i f - - - - - l - - - - - -- - - - i

(c)
0.2

S2

0.1
0.0

,t-+--...\ :±++¥t+=th,+tH' •
10

I

I

I

15

=+-=..~+
20

Excitation Energy (MeV)

Fig . 1. Measured (d, d') spectra on 28Si at Ed = 270 MeV.
(a) Double-differential cross section. (b) Spin-flip probability, SI. (c) Double-spin-flip probability, S2.

and 10.18 Me V. Figure 1 (b) shows the spectrum of

8 1 . The isoscalar 1+ state at 9.50 Me V is enhanced inthis spectrum, while other non-spin-flip states are all
suppressed, in accordance with spin-flip nature of thesestates. One may also see slightly enhanced 8 1 values
relative to those for free deuteron-nucleon (d-N) scattering (shown by the dashed line) over the excitationenergy Ex ~ 11-18 MeV region. It would be interesting to note that several T = 0, 1+ states have recently
been reported over the Ex region of 9.7-15.8 MeV. 4 )Figure 1 (c) shows the 8 2 spectrum. The 8 2 values arefound to be close to zero for all of the measured Ex region. Within the framework of PWIA, it is necessary
to have 8 2 = 0 if we assume a one-step reaction process
without any contribution from the tensor terms in thed-N t-matrix. 5 ) Such an assumption is expected to bevalid in the low-momentum transfer kinematics of thepresent experiment.
References
1) M. Morlet et al.: Phys. Lett. B 247 , 228 (1990).
2) P. Vogel et al.: Phys. Lett. B 212 , 259 (1988); N. Auerbach et al.: Ann. Phys. 192 , 77 (1989).
3) S. Ishida et al.: AlP Conf. Proc. 343 , 182 (1995).
4) Y. Fujita et al.: Phys. Rev. C 55 , 1137 (1997).
5) T. Suzuki: Prog. Theor. Phys. 86 , 1129 (1991).

RIKEN Accel. Prog. Rep. 33 (2000)

Proton Spectra from the 208Pb+ 208 Pb Reaction at 15 A MeV,;
K. Yoshida, M. Shimooka, R. Wada, T. Nakagawa, K. Nakagawa,1. Tanihata, Y. Aoki, J. Kasagi, and W. Q. Shen*[208Pb+ 208 Pb 15 A MeV, Fission]
The proton energy spectra have been measured forthe 208Pb+ 2o8 Pb reaction at 15 A MeV to investigate
the formation of a very heavy compound nucleus. Dueto the strong Coulomb repulsion, it has been thoughtthat the formation of a compound nucleus is strongly
hindered in collisions between heavy nuclei, such as
208Pb+ 2o8 Pb. However, recent theoretical calculations
suggest that a heavy compound nucleus can be formedin heavy nucleus-nucleus collisions at sufficiently highincident energies to overcome the strong Coulomb repulsion. The proton energy spectrum is expected to bea good measure of the formation of the compound nucleus, since the large Coulomb barrier strongly affects
the protons evaporated from the compound nucleus.
In order to minimize the strong contribution from thedeep inelastic scattering, protons were detected in coincidence with three large fragments, which were produced from the compound nucleus through ternary fission.
The experiment was performed at the RIKEN Ring
Cyclotron. 208Pb beams with an energy of 15 A MeV
and an intensity of 0.1 pnA were bombarded onto a
99.9%-enriched 208Pb foil of 1 mg/cm 2 in thickness
backed with 20 J-lg/cm 2 collodion. Protons were detected with BaF 2 phoswich detectors,l) which covered130-165° laboratory angles around the beam axis. A
large PPAC/IC chamber 2) was placed at 25-75° laboratory angles in order to measure the energies andvelocities of the fission fragments.
The proton spectra have been deduced for two typesof the spatial distributions of three detected fragments.
One is the asymmetric one: one of the folding angles ofthe fragments is about 60°, and the others are about
150° . The other is a symmetric one: all three folding angles are nearly 120°. The correlation among thevelocities of the fragments suggests that the former
events come from the fission of the projectile or target
nuclei after deep inelastic scattering, and the latter isassociated with a simultaneous breakup of three fragments .
The proton spectra observed at two different laboratory angles are shown in Fig. 1 for two types of fragment distributions. As can be seen, the spectra forboth cases are similar except for Ep < 10 MeV. Yieldsof the protons decreased exponentially with increasing
their energies. Below 8 MeV, the yield decreased alongwith a decrease in the proton energy for the symmetric

b)

a)

0.1

0.01
::::l

.i
"0

Q5

>= 0.001

0.0001

10-5u..........I...l....&..I..J...I....i...........L.Lu..~...I...l....&..J...o..I..A..u.....I..J...I....i...L..L...L.Ju........u...U...u..L.1..I..>-L....u...Ju..J...Jo

5

10 15 20 25

05

10 15 20 25 30

Ep (MeV)Fig. 1. Proton energy spectra in coincidence with threefragments from the 208Pb+ 2o8 Pb reaction at 15 A MeV.
a) Protons coincidence with the asymmetric distribution of the three fragments . b) Protons for the symmetric distribution of the fragments. Lines are resultsof the Monte CaIro simulation.

distribution, whereas the spectra for the asymmetric
distribution remain almost constant.
Monte Cairo simulations were performed to investigate the proton spectrum expected from the statistical
decay of the fragments. The code SIMON 3 ) was employed to simulate , the fission of the nuclei from thedeep inelastic scattering; the results were comparedwith the spectrum for the asymmetric distributions.
For symmetric distributions, a special code was developed to simulate the ternary fission following thecomplete fusion. The results are shown by the lines inFig. 1. The observed spectra were reasonably reproduced by those simulations.
References
1) Y. Futami et al.: Nucl. Instrum. Methods Phys. Res. A
329, 513 (1993).
2) K. Yoshida et al.: RIKEN Accel. Prog. Rep. 31, 165(1998).
3) D. Durand: Nucl. Phys. A 541, 266 (1992).

Shanghai Institute of Nuclear Research, Chinese Academyof Science, China

57

RIKEN Accel. Prog. Rep. 33 (2000)

GDR f.-rays from the Binary Reaction of 209Bi + 209Bi ~t 12 MeV lu
Y. Aoki, J. Kasagi, K. Yoshida, T. Nakagawa, and K. Nakagaw&
NUCLEAR REACTION, 209Bi+ 2o9 Bi EI A = 12 MeV lu; Inelastic scattering; Measured][ high energy "'( rays, protons, and residues; Deduced GDR response
A study of the GDR built on highly excited nuclei is
one of the interesting subjects to understand the properties of hot nuclei. There have been many studies
concerning on the GDR of hot nuclei in the Sn region.
These studies show that the width of the GDR increases with an increase in the nuclear temperature up
to 3 MeV, and then saturates at higher temperature.
For heavier nuclei, the experimental data are scarce.
The GDR of hot 208Pb excited up to the nuclear temperature T = 2 MeV by Q inelastic scattering!) showsthat the width of GDR increases rapidly along withan increase of the temperature. In order to study
the GDR of heavy nuclei at higher temperature, wemeasured GDR ",(-rays from the 209Bi + 209Bi inelastic
scattering.
The experiment was carried out at the ASCHRA
chamber in the RIKEN RING Cyclotron. An accelerated 209Bi beam with an energy of 12 MeV lu andan intensity of 0.1 pnA irradiated a 1 mg/cm 2 209Bi
self-support target . The residual nuclei of the reaction
were detected by 3 large PPAC+lonization chambers.
The Tof and position of the residues were measured by
PPACs, and their energy was measured by ionizationchambers. The masses of the residues were deduced
from these information. The high-energy "'( rays were
measured by 2 sets of high-energy "'(-ray detectors consisting of 7 BaF 2 scintillators. The multiplicities ofthe "'( rays and the charged particles were also measured by a crystal ball consisting of 65 BaF 2- plastic
phoswich detectors.
The "'( ray spectra were obtained for the four excitation bins by selecting the observed masses larger than175. The excitation energies were calculated from theangles and velocities of the detected residues by assuming 2-body kinematics. The excitation energies of
the residues were ensured by the shape of the energy
spectra of protons detected with the crystal ball. The
observed spectra were well reproduced by statisticalmodel simulations with the excitation energies being
deduced from 2-body kinematics.
The "'(-ray spectra were compared with statistical-

58,-.., 20

>
IU

6 18
16
14

12
8:
r.,....'"

10
8
6
4

2

o0

0.5

1.5

T

2

2.5

3

3.5

4
(MeV)

Fig. 1. CDR width plotted against the nuclear temperature. The closed circles are the present results and theopen circles are from Ref. 1. The solid line represents
the calcution of Ormand et al. 2 ) The dashed line is therelation rCDR = 4.0 + 0.89 T2.

model calculations using the code CASCADE. The
GDR energies and widths were deduced from a X 2 fitting of the calculated spectra and experimental spectra. In Fig. 1, the deduced GDR widths are plottedversus temperature along with the data from Ref. 1.
As can be seen, the present result agrees with the datafrom Ref. 1. The G D R widths increase in proportion to
T2 in low excitation energies. At higher temperatures,
however, the widths saturate at r G = 11 MeV. The
result agrees well with the theoretical work of Ormand
et al. 2 ) in all temperature regions.
References
1) E. Ramakrishnan et a1.: Phys. Lett. B 383, 252 (1996).
2) W. E. Ormand et a1.: Phys. Rev. Lett. 77, 607 (1996).

RIKEN Accel. Prog. Rep. 33 (2000)

Search for a Z = 118 Superheavy Nucleus
in the .Reaction of 8 4 Kr with 208Pb
K. Morimoto, 1. Tanihata, N. Iwasa,R. Kanungo, T. Kato, K. Katori, H. Kudo, K. Morita, T. Suda,
S. Takeuchi, F. Tokanai, K. Uchiyama, Y. Wakasaya, T . .Yamaguchi, A. Yoneda, and A. Yoshida[NUCLEAR REACTION, Gas-filled recoil ~eparator, Alpha-decays]
Recently, three decay chains for a reaction of 86Kr
with 208Pb were reported by a Lawrence Berkeley Laboratory group . 1) The observed chains are consistent
with the formation of 293 118 and its sequential Q decays. However, the decay chains are not connected to
any known nuclei. The observed production cross section is 2.2 (+2.6, -0.8) pb. This experiment was performed following a recent prediction of Smolanczuk,2)which indicates that the cross section of a cold-fusion
reaction of 86Kr with 208Pb is 670 pb. This is a drastically larger value than scientists have thought.
In a private communication, T. Wada, M. Ohta,
Y. Aritomo, and Y. Abe suggest that the cross sectionof a cold-fusion reaction of 84Kr with 208Pb should bealmost the same as that of 86Kr with 208Pb. If thecross section of 86Kr with 208Pb is confident, we havea chance to observe 291 118 with decay chains connectedto the known nuclei. From that view, we conducted anexperiment to observe the superheavy nucleus 291 118
produced in the reaction of 84Kr with 208Pb.
The experimental set up is shown in Fig. 1. The target thickness was 300 j.1g/ em 2; it was evaporated onto
the downstream side of a 100 j.1g/cm 2 carbon foil. Six
segments of it were mounted on a wheel that rotated
at 600 rpm. The beam energy was 446 MeV, and the
maximum beam current was 1000 particle nanoamperes. The incident beam energy at the center of thetarget was 442.2 MeV. To avoid the primary beam from
Elastic Monitor ~
(SSD)
/

SSD

GARIS

/

I

Primary beam

r
PSD

/

/

T 0 F

Stripper foil

Fig. 1. Schematic drawing of the setup.

impinging on the silicon detector in the event of abroken target, a carbon foil of 30 j.1g/cm 2 thick was
mounted as a charge stripper of primary beams. The
beam intensity was monitored through elastic scattering by a silicon detector installed at 45 degrees withrespect to the incident beam.
The reaction products recoiling out of the target
were separated from the. primary beam by using a
gas-filled recoil separator, GARIS. 3) The separator was
filled with He gas at one torr. The optimal magnetic
field setting was obtained by scaling the value fromthe measured focal plane evaporation residue distribution of 84Kr+107 Ag. We have estimated the magnetic rigidity (Bp) to be 2.2 Tm. After the separator the recoil particles were implanted in a positionsensitive silicon detector (PSD), which had an active
area of 60 x 60 mm with a depth of 300 j.1m. Passingthrough light particles were anti-coincided with veto
SSD mounted after the PSD . Total counting rate of
the PSD was several counts/sec under the condition
with 1000 particle nanoamperes beam intensity. The
time-of-flight measurement was additionally performed
using a micrO-channel plate assembly (MCP) and thePSD.
We had two experimental machine times. The firstexperiment (4 days) was performed for a test of targets,an estimation of the magnetic rigidity (Bp), calibrations of detectors and a check of the data-acquisition
system. The second experiment (10 days) was performed to accumulate a dose of 2 x 10 18 ions, but nocandidate of the evaporation residue was found.

V.'o $,"

References
1) V. Ninov et al.: Phys. Rev. Lett. 83, 1104 (1999) .
2) R. Smolanczuk: Rhys. Rev. C 59, 2634 (1999).
3) K. Morita et al.: Nuel. Instrum. Methods Phys. Res. B
70, 220 (1992).

59

RIKEN Accel. Prog. Rep. 33 (2000)

First Measurement of the 8B(p,,)9C Reaction by
the Coulomb-Dissociation Method
T. Motobayashi, 1. Hisanaga, H. Akiyoshi, Y. Ando, H. Fujiwara,·l N. Fukuda, Zs. Fiilop,
T. Gomi, K. 1. Hahn,·2 Y. Higurashi., M. Hirai, M. Ishihara, N. Iwasa, H. Iwasaki,
Y. Iwata,·3 T. Kijima,·4 S. Kubono, T. Minemura, T. Nakamura, M. Notani,S. Ozawa, S. Shimoura, S. Takeuchi, T. Teranishi, and Y. Yanagisawa[Pb(9C,BB p)Pb, Coulomb dissociation, Astrophysical S-factor for BB(p,,)9C]
The first experimental study of the BB(p,,)9C reaction was performed with the Coulomb-dissociation
method. This reaction at low energies is one of the
key processes in the hot pp mode nuclear burning. I)
At very high temperatures of around lOB K and highdensities of p > 10 5 g/cm 3 in a hydrogen-rich circumstance, the proton capture of BB becomes faster thanthe (3+ decay of BB. The reaction is also related tothe 7Li production in novae. 2) No experimental information is available so far for the BB(p,,)9C reaction,
because its direct-capture experiment is very difficult
due to the short h'a lf life of 770 ms for BB. Thoughexperiments in inverse kinematics, where a radioactive
BB beam bombards a hydrogen target, is in principle
possible, the Coulomb-dissociation method has an advantage of high experimental efficiency caused by thelarger cross section and the allowance of using a muchthicker target.
The RIPS system provided radioactive 9C beams
at 65 A Me V using the projectile fragmentation of a
135 A MeV 12C beam with a 1.64 g/cm 2 9Be target.
The secondary 9C beam bombarded a 100 mg/cm 2
lead target set at the final focal point of the RIPS. The
outgoing proton and BB were detected in coincidence
by a plastic-scintillator hodoscope of 1 x 1 m 2 area ina vacuum chamber, the details of which have been reported elsewhere. 3) From the measured time-of-flightand hit positions of the two fragments, their relative
energy, which corresponds to the center-of-massenergy for the BB(p,,)9C reaction, was obtained.
The extracted Coulomb-dissociation yield is plottedin Fig. 1 as a function of the p_BB relative energy.
The histogram represents the result of a simulation
calculation that accounts for the detector response,
which is affected by the uncertainties of the angle- andenergy-determination in the hodoscope and the coincidence efficiency for the pair of fragments. A constantastrophysical S-factor of 100 eV-b was assumed for
the BB(p,,)9C reaction in the simulation. The data
were reasonably well reproduced by the simulation,* 1 Accelerator Engineering Corporation
Department of Physics Ewha Womens University, Korea*3 National Institute of Radiological Sciences*4 Faculty of Engineering, Yokohama National University

*2

·60

15

+ 9 C+Pb ~ 8B + p +Pb+ +++E =65 A MeV
in

+

o

+

~~~~~~~~~~~~~~~~~

o

0.5

1.5
E rel [MeV]

2

2.5

3

Fig. 1. Relative energy spectrum obtained for the protonand 8B produced by the Coulomb dissociation of 9C.

except for the excess of the yield at around 1 MeV,
originating from the first excited state in 9C at Ex =2.218 MeV, corresponding to the relative energy Erel =0.922 MeV.
The present result suggests that the S factor for theBB(p,,)9C reaction for the continuum region is approximately 100 eV-b. This value is closer to a predictionof Descouvemont 4 ) of about 70 eV-b than that of Wiescher et at.,l) who estimate an averaged S factor of
210 eV-b for Ecm < 0.8 MeV. Further analysis including an evaluation of the nuclear contribution is inprogress.
References
1) M . Wiescher et al.: Astrophys . J. 343 , 352 (1989).
2) H. M. J. Boffin et al.: Astron . Astrophys.

279, 173(1993).
3) N. Iwasa et al.: J. Phys . Soc. Jpn. 65 1256 (1996);
I. Hisanaga et al.: RIKEN Accel. Prog. Rep. 31 , 162(1998).
4) P. Descouvemont: Astrophys. J. 405, 518 (1993).

O.5mmt Stainless Steel Chamber for Vacuum

O.Smmt Plastic Scintillation Counter
Light Guide
Photo Multiplier Tube

Fig. 2. A schematic layout of plastic scintillation counters for {3-ray counting around theceratron as a beam catcher. The {3-ray counter telescope can be separated into 5 plastic
scintillation counters. Each scintillation counter has a photomultiplier tube. Eight orfour twisted light guides connect between the photomultiplier tube and scintillators.

structed an ion separator and a set of /3-ray counters.
A schematic drawing of the separation and counting
systems is shown in Fig. 1. This beam line has two foci.
One dipole magnet is used to separate 11 Li (or otherlithium isotopes) from other species of ions.The Li-ion
counting system around the final focus (® in Fig. 1)
is shown in Fig. 2. A ceratron (channel type electron
multiplier) is placed in a plastic scintillation counter
telescope as a beam catcher. The plastic scintillation
counters are suitable for one-by-one counting of the /3
rays emitted from 8Li, 9Li or 11 Li nuclei, which stopin the catcher, while the ceratron is used as well forthe detection of Li isotope ions through the currentof secondary electrons which they produce.
The
plastic scintillation counter telescope consists of threelayers, i.e., inner, middle and outer layer, which coverabout 27r of the solid angle around the catcher. The

62

inner counter is made with 8 scintillator plates combined as an octagon prism. The middle counter consists of two parts, which covers the upper and lower
half (7r solid angle) of the catcher. Both parts are madewith 4 plastic scintillator plates, and are constructedwith the same configuration as the inner counter. The
outer counter has the same structure as the middle
counter. The signals from two middle (and the outer)counters are used to produce anticoincidenced logic signals to reduce the background from cosmic rays.
At present , the construction of this system has been
completed, and its beam-transport efficiency is to bemeasured by using stable Li ions. The stable Li
beam had been introduced to the first focal point until
November, 1999; the lithium beam for this test will betransported to the final catcher soon.

RIKEN Accel. Prog. Rep. 33 (2000)

Coulomb Dissociation of 12N and 13 0
T. Minemura, T. Motobayashi, S. Shimoura, H. Murakami, Y. Ando, T. Teranishi, N. Aoi, Zs. FUlop, M. Hirai,
H. Iwasaki, N. Imai, N. Iwasa, M. Kurokawa, H. Akiyoshi, Y. Yanagisawa, Y. Iwata, S. Ozawa, S. Takeuchi,
Y. Higurashi, M. Serata, H. Kobayashi, K. Yamada, T. Gomi, H. Sakurai, K. Yoshida,
Z. Liu, and M. Ishihara

1

208 Pb (12 N ,lIC p)208Pb, 208Pb( 13 0, 12 N p)208Pb, Coulomb d"lssoclation, Re1ative energy[spectra
The Coulomb breakup technique was employed todetermine the radiative width of excited levels in 12N
and 130, which dominate the low-energy cross sections of the l1C(P,r) 12 N and 12N(P,r)130 reactions.
These reactions are important in the hot pp mode
nuclear burning in hydrogen-rich massive objects. I)
Under a high-temperature and high-density condition,these capture reactions become faster than the ;3+ decay of l1C and 12N. However, these lIC(P,r) 12 N and
12N(P,r) 13 0 reactions are difficult to study experimentally because the life times of llC and 12N are too shortto prepare them as targets.
For the present 12N-dissociation experiment, therelative-energy resolution is better than that in theexperiment at GANIL,2) and a lower background was
realized compared with our previous measurement at
RIKEN.3) The latter improvement was achieved by installing the entire detector in a vacuum chamber. In
the energy region of astrophysical interest, two resonant states are known for 12N, 2+ at Eex = 0.960 MeV
and 2- at Eex = 1.19 MeV, corresponding to the
p_llC center-of-mass energy, Eern = 0.359 MeV and
0.589 MeV, respectively. For 13 0, only one resonant
state is known at the p_12N center-of-mass energy Eern
= 1.23 MeV, corresponding to the excited state at Eex= 2.75 MeV, whose spin has not been confirmed.
The experiments have been performed at
RIKEN using the secondary beam line, RIPS. A
77.0 MeV/nucleon 12N beam and a 83.5 MeV/nucleon
130 radioactive beam were produced through fragmentation reactions of a primary 135 MeV/nucleon
160 beam. A 30 mg/cm 2 208Pb target was bombarded
by a secondary 12N beam, and a 55 mg/cm 2 208Pb
target was bombarded by a secondary 13 0 beam. The
breakup fragments, llC and a proton or 12N and a
proton, were detected in coincidence after travelingthrough a 5.1 m flight-path by a plastic scintillator
hodoscope. From the fragments' velocities, measured
by their time-of-flight and their hit positions in thehodoscope, we could reconstruct the p_llC and thep_12N relative energies.
The p_lIC relative-energy spectrum obtained in the
12N-dissociation experiment is shown in Fig. 1 (a). The
open circles represent the data obtained in this work.
The solid curve shows the result of a Monte Carlo simulation assuming three contributions, two resonances at2(E.- 1.19)

0.03

:;-

2+

:::2

(E.-O.96)eV"..0 0.02
Czl°'tI(a) 1\ c( p. 'Y )la N

V

Q)

t

t

'b' 0.01
'E

0.00
3

:;Q)

:::2

".c

S
'8

2

Czlu
'tI

"0

'E

0

0

0 .5

Fig. 1. (a) Relative energy spectrum obtained for the
208Pbe 2N,l1C p)208Pb reaction. The solid curve represents the results of a Monte-Carlo simulation, comprising the three components shown by the dashedcurves. (b) Relative energy spectrum obtained for the
208Pbe 3 0/ 2N p)208Pb reaction .

Eern = 0.359 MeV and 0.589 MeV, and a direct proton
capture, whose magnitudes were treated as fitting parameters. As can be seen in Fig. 1, the bump observedat around 0.6 MeV is found to be mainly due to theE1 transition from the 1+ ground state to the 2- state
at Eex = 1.19 MeV. The r-width of the 2- state is extracted from the fit to be r 'Y ~ 20 meV, which is in between the two different predictions by Wiescher et al. 4 )(2 meV) and Descouvemont and Baraffe 5 ) (140 meV),and disagrees with the results of the GANIL experiment (6~~.5 meV).
For 13 0 dissociation, the experimental relativeenergy spectrum shown in Fig. l(b) exhibits a bump.
It might contain some extra strength in addition to theE1 strength to the resonance at Eex = 2.75 MeV. The
sum of these strengths corresponds to r 'Y ~ 3 eV, which
is much higher than expected in Ref. 4 (Wiescher).
A more complete analysis of the data, including acorrection due to the 12N ~ P + lIC* and 130 --t p +12N* channels, is under way.

63

References
1) A. Jorissen and M. Arnould: Astron. Astrophys. 221,
116 (198~).
2) A. Lefebvre et al.: Nucl. Phys. A 592, 69 (1995).
3) T. Minemura et al.: RIKEN. Accel. Prog. Rep. 31 , 69

64

(1998).
4) M. Wiescher, J . Gorres, S. Graff, L. Buchmann, and F .
K. Thielemann: Astrophy. J. 343, 352 (1989).
5) P. Descouvemont and I. Baraffe: Nucl. Phys. A 514, 66(1990).

RIKEN Accel. Prog. Rep. 33 (2000)

Coulomb DissociatJon of 13Nand 14 0
M. Serata, T. Motobayashi, S. Shimoura, H. Akiyoshi, Y. Ando, N. Aoi, Zs. FUlop, T. Gomi, Y. Higurashi,
M .. Hirai, K .. Ieki, N. Imai, N. Iwasa, H. Iwasaki, Y. Iwata, H. Kobayashi, M. Kurokawa, T. Minemura,
H. Murakami, S. Ozawa, H. Sakurai, S. Takeuchi, T. Teranishi, K. Yamada, Y. Yanagisawa,
K. Yoshida, Z. Liu, and M. Ishihara
NUCLEAR REACTIONS: 208Pbe 40,p 13 N)208Pb, 85 A MeV; 208Pbe3N,p12C)208Pb,][ 76 A MeV
The Coulomb dissociation method 1) has been successfully applied to various astrophysical (p,l') reactions. However, the validity of the method has notbeen tested to high precision. For that purpose, we
studied the Coulomb dissociation of 13N and 14 0. The
12C(p,I')13N reaction, which corresponds to 13N dissociation, has been well studied, and its cross section is known to good accuracy. Experiments concerning 13N and 14 0 dissociation have already been
performed at RIKEN. 2) Dissociation of 14 0 has also
been studied at GANIL .3) The results of these experiments agree with a direct measurement performed at
Louvain-La-Neuve 4) within the errors. However, these
agreements are confirmed at accuracies of around 30%.
The present experiment is aimed at improving the experimental accuracy by reducing the systematic uncertainties with a lower background and a higher relative
energy resolution.
Beams of 13N and 14 0 were produced by using the
projectile fragmentation of a 135 MeV/nucleon 16 0
beam on a 1480 mg/cm 2 9Be target. These beams
were separated by the RIPS from other fragments, andwere focused on a Pb or a C target with the thickness of 55 or 37 mg/cm 2, respectively. The thickness of the Pb target was about seven-times as thin
as that used in a previous experiment. 2) This reduced
multiple scattering of the products, and hence improved the angular resolution. The averaged energies
were 76 MeV/nucleon and 85 MeV/nucleon, respectively, for 13N and 14 0 at the middle of the target.
Outgoing charged particles were detected by a ~E-E
hodoscopes. 5 ) The velocities of the particles were determined by their time-of-flight(TOF) for a path lengthof 5 m. The momentum vectors of the particles were
determined by combining their velocities with the hit
positions on the hodoscope, and were used to calculate
the relative energies of the breakup fragments measured in coincidence. Together with an improved energy resolution, resulting from the TOF measurement,a better relative-energy resolution was possible compared with that in a previous experiment. 2)
Figure 1 shows the relative energy spectra forthe correlated p_12C 'and p_13N pairs generating,counts
600
500

I
F-

400

F-

200

F-

100

F-

0
0

I

0

-

J

o

2

4

relative energy (Mev)counts
120
100
80

60

40
20
2

relative energy (Mev)

Fig. 1. Relative energy spectrum for the Coulomb dissociation of 13N and 14 0 .

respectively, from the Coulomb dissociation of 13N and
14
0. The prominent peaks around at 500 keV correspond to the lowest E1 resonances in 13N and 14 0. It
is known that the (p,l') processes through these resonances dominate in stellar burning. Therefore, any
comparision to the direct-capture data should be madeconcerning their yield. The widths (FWHM) of thepeaks in the observed spectra were 310 keV ( 14 0) and250 keV 3 N) . These resolutions are better by a factor of two than those in the previous experiment at
RIKEN. 2) This is because of the better angular andenergy resolutions of the present measurement.
An accurate determination of the r'Y values of the E1
transitions, which determine the (p,l') reaction rates,
is now in progress.

e

References
1) G. Baur et al.: Nucl. Phys. A 458, 188 (1986) . .
2) T . Motobayashi et al.: Phys . Lett. B 264, 259 (1991) .
3) J. Kiener et al.: Nucl. Phys. A 552, 66 (1993).
4) P. Decrock et al.: Phys. Rev. Lett. 67, 808 (1991).
5) 1. Hisanaga et al.: RIKEN. Accel. Prog. Rep. 31, 162(1998).

65

RIKEN Accel. Prog. Rep. 33 (2000)

Isobaric Analog State of 14Be
S. Takeuchi, S. Shimoura, T. Motobayashi, H. Akiyoshi, Y. Ando, N. Aoi, Zs. Ftilop, T. Gomi, Y. 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
NUCLEAR REACTIONS: 1,2H(14Be,14B*), 74 A MeV; Charge exchange reaction; Isobaric][ analog state; Neutron halo
The Isobaric Analog State (lAS) of the neutron halo
nucleus, 14Be, has been investigated using the chargeexchange reaction 14Be(p,n)14B* in inverse kinematics at E(14Be) = 74 A MeV. The present study was
aimed at determining the energy ofIAS(14B*), and understanding the neutron halo structure of 14Be. The
charge-exchange reaction is useful to study lAS, andwas successfully applied in a recent study on the neutron halo nucleus 11 Li. 1,2) The lAS of 14Be is characterised by its isospin of T = 3, while other populated states are mostly of T = 2, and it decays to the
12Be+p+n channel (T = 3 and 2) because of isospin
conservation. Thus, the lAS can be revealed by detecting a 12Be, proton and neutron in coincidence.
A secondary 14Be beam was produced by using the
projectile fragmentation of a 100 A MeV 18 0 beam
at a 1110 mg/cm 2 gBe target and focused on (CH 2 )nand C targets . The decay particles from 14B* weredetected by ~E and E hodoscopes, which were located492 cm downstream of the target; the time-of-flight(TOF) from the target to the hodoscopes and the hit
position were measured. The momentum vectors ofthe decaying particles were determined by combining
their velocities and hit positions on the hodoscope.
The extracted momentum vectors were used to construct the decay energy spectrum of the 12Be+p+nsystem, which is the difference between the invariant
mass and the threshold energy, L,iMi (total rest massof all decay particles):Ed = Me 4 B*) - EiMi.

,.......,

(1)

0.8

0.8

0.6

0.6

>
()

0.4

"t:I
(""I"

>

Q)

::!1

...........

,.c

()

S 0.4-

CD

L--I

~

'tI

::I

r.:l

'U

...........
b

()

0.2

0.2

CD

'U
\Ll

0.0
0.0

0.5

1.0

1.5

2.0

2.5

3.0

0.0

2
Blab

3

4

[deg]

Fig. 2. Angular distribution of 14B*. The solid line represents a Gaussian distribution.
Figure 1 shows the decay energy spectrum of the
12Be+p+n system for the (p,n) reaction, which was
obtained by subtracting the spectrum of the C target
from that of the (CH 2 )n target. A sharp peak is observed at Ed ~ 0.3 MeV, which is not observed in the
C target spectrum. Most of the events consisting of thepeak were derived from the Fermi transition which was
suppressed in a reaction using a C target. The peak
was fitted with a Gaussian function; the effects of the
Ed resolution and the detector acceptance were taken
into account in the fitting procedure. The energy ofthe lAS was deduced to be 0.29 ± 0.03 MeV, where theerror was derived from the uncertainty in the absolutemagnitude of the TOF. Using a threshold energy of
16.77 MeV for 12Be+p+n channel, the excitation energy of the lAS was determined to be 17.06±0.03 MeV
with respect to the ground state of 14B.
The angular distribution of 14 B *(lAS) is shown in
Fig. 2, where the events in the lAS peak are plotted
as a function of the angle of the center-of-mass for the
12Be+p+n system. The distribution is forward peaking and can be approximated by a Gaussian function
centered at 0 degree. Such an angular distribution
is characteristic of the t:::.L = 0 angular momentum
transfer, which is required for Fermi transitions. Thus,
the observed forward peaking angular distribution supports the assignment of the peak in Fig. 1 to the lASof 14Be populated by the Fermi transition.

Ede 2 Be+p+n) [MeV]
References
Fig. 1. Decay-energy spectrum of the 12Be+p+n system.
The solid line shows the detector acceptance.

661) S. Shimoura et al.: Nucl. Phys. A 630, 387c (1997).
2) T. Teranishi et al.: Phys. Lett. B 407, 110 (1997) .

RIKEN Accel. Prog. Rep. 33 (2000)

Coulomb Excitation of ~50
K. Yamada, T. Motobayashi, S. Shimoura, Y. Iwata, S. Ozawa, H. Kobayashi, T. Gomi, M. Serata, S. Takeuchi,
Y. Higurashi, T. Minemura, Y. Yanagisawa, N. Aoi, H. Iwasaki, N. Imai; H. Sakurai, T. Teranishi, K. Yoshida,
H. Akiyoshi, N. Iwasa, M. Kurokawa, Z. Liu, Zs. Fiilop, and M. Ishihara
NUCLEAR REACTIONS: 208Pbe 50, 15 0*), 100 MeV lu; Coulomb excitation reaction, NU-]
[ clear astrophysics,
The CNO cycle has a certain effect on the rate ofnuclear burning in the sun. At solar temperatures,the reaction 14N(p,,)150 determines the rate of themain CNO cycle, because its reaction rate is almost
100-times slower than the other CNO reactions. The
behavior of the 14N(p,,)150 cross section at energies
close to the threshold is not fully understood. Especially, a significant contribution to the ground-state
capture from the subthreshold resonance at 504 ke V
below the p + 14N threshold, which corresponds tothe 3/2+ state at 6.79 MeV in 15 0, has been pointed
out ,l) but has not been studied experimentally. The
present study was aimed at measuring r'Y of 15 0 in
order to clarify the role of this subthreshold state by
the Coulomb excitation method.
A beam of 15 0 was produced by using the projectile fragmentation of a 135 MeV lu 160 beam incident
on a 9Be target, and selected by the RIKEN projectileflagment separator (RIPS). The 15 0 beam was focused
onto a 1480 mg/cm 2 208Pb target at 300- 400 kcps. The
average beam energy was 85 MeV lu at the middle ofthe target. A 1.0 mm thick plastic scintillator was located at the first achromatic focal plane of RIPS (F2).
Particle-identification of the 15 0 beam was carried out
by a time-of-flight measured between F2 and the cyclotron RF signals. A plastic scintillator hodoscope 2)
consisting of ~E and E walls was placed 499 cm downstream from the target to detect the scattered 150,
which was identified by measuring the energies deposited in the ~E and E detectors together with thetime-of-flight. An array of 64 NaI(TI) scintillators set
around the target was used to detect ,-rays with anefficiency of 20% for 6.79 MeV photons from 15 0 nuclei in flight with f3 = vic ~ 0.4. The Doppler effects
were corrected by the ,-ray emission angle determinedfor each crystal.
The histograms in Fig. 1 show the Doppler-corrected,-ray spectra measured in coincidence with inelastically scattered 15 0 at e = 63° and 86°, respectively.
No distinct peak can be observed at 6. 79 MeV, sufferedby the background photons originating from the target excitation. The distributions exhibiting peaks in
Fig. 1 represent the spectra expected for two different

63

800
I'll
+J

600

0

400

~
;:j

u

0

200

10

8
4
6
E1[Me V] layerO

600
I'll
+J

~

;:j

(b)
By = 86r;,= O.87eV

0

400

0

u
200

4

6
8
E1[Me V] layer 1

10Fig. 1. Doppler-corrected ,-ray spectrum measured at thedetector angles e = 63° (a) and e = 86° (b).

r'Y values, 0.87 eV3 ) and 6.3 eV. 1) The detector responce was calculated by a Monte-Carlo simulation.
Apparently, the larger value of 6.3 eV can be excluded
by a comparison with the data, whereas the lower estimate, r'Y = 0.87 eV, is compatible with the data. Thus,
the present results suggest that r 'Y ~ 1 eV, pointing
to only a minor effect of the 6.79 MeV state in 15 0 on
the low-energy 14N(p,,)150 cross section.
References
1) U. Schroder et al.: Nucl. Phys. A 467, 240 (1987).
2) I. Hisanaga et al.: RIKEN Accel. Prog. Rep. 31, 162(1998).
3) R . Moreh et al.: Phys. Rev. C 23, 988 (1981).

67

RIKEN Accel. Prog. Rep . 33 (2000)

Coulomb Excitation of 28Ne and 32, 34 Mg
H. Iwasaki, T. Motobayashi, K. Yoneda, T. Gomi, H. Sakurai, N. Aoi, N. Fukuda, ZS. Fiilop, U. Futakami,
Z. Gacsi, Y. Higurashi, N. Imai, N. Iwasa, T. Kubo, M. Kunibu, M. Kurokawa, Z. Liu, T. Minemura,.
A. Saito, M. Serata, S. Shimoura, 8. Takeuchi, Y. X . Watanabe, K. Yamada,
Y. Yanagisawa, and M. Ishihara
NUCLEAR REACTIONS: Pb, C[excitation, Deduced B(E2)eBNe, 2B Ne,), e2Mg, 32 Mg,), e4Mg,34 Mg,), coulomb]

The first experiment involving the Coulomb excitation of 32Mg has demonstrated the usefulness of theintermediate-energy Coulomb excitation technique forstudies of low-lying states in nuclei far from the stability line. 1) Experimental studies with this techniquehave revealed that some neutron-rich nuclei, such as
32Mg and 448, have large quadrupole collectivity inspite of the neutron-shell closures at N = 20 and
N = 28. 1 ,2)
We performed measurements of the excitation energies and B(E2) values for the 2t states of the neutronrich nuclei 28Ne and 32,34 Mg via intermediate-energy
Coulomb excitation. Here, we report on the experimental arrangement.
The nuclei studied in the present work were produced by fragmentation of a 95 MeV /u 40 Ar beam
impinging on a 463 mg/cm 3 9Be target. The reaction
fragments were collected and analysed by the RIKEN
projectile-fragment separator (RIPS)3) operated at
the maximum values of the momentum acceptanceand solid angle. A thick aluminum wedge was used toallow a unique isotopic identification of the fragments.
The obtained intensities for secondary beams weretypically 100 s-1 8Ne), 1000 s-1 2Mg), and 4 S-1
4Mg). Particle identification of the incident beam
was carried out event-by-event using the time-of-flight(TOF)-~E method.
The TOF was determined by
two 0.3 mm thick plastic scintillators placed 5.2 m
apart in the beam line. The ~E information wasmeasured by a 0.35 mm thick silicon detector placedat the first achromatic focal plane (F2) of RIPS. The
horizontal and vertical positions of the fragments
at F2 were measured by a parallel-plate avalanche
counter (PPAC). The horizontal position at F2 wasincorporated in the particle identification.
Leadtargets were placed at the final focal plane (F3)and used to excite the projectiles. The thicknessesof the lead targets were 693 mg/cm 3 for the 28Ne
and 34 Mg measurements and 573 mg/ cm 3 for the
32Mg measurement. In addition, measurements withcarbon targets were performed in order to study any
possible contributions of nuclear excitations. The
position and incident angles of the beam at the target were measured by two sets of PPAC's placed at F3.

e

68

e

e

The number of the incident beam was counted by a
0.3 mm thick plastic scintillator placed 40 cm downstream of the target.
Scattered particles were detected by a counter telescope located 43 cm downstream of the target. The
telescope comprised 4 layers of ion-implanted silicondetectors. The thicknesses of the silicon detectors were0.5, 1.0, 1.0, 0.5 mm, respectively. The first silicondetector was a double-sided type , which divided into
16 strips both horizontally and vertically. The positions of scattered particles were determined by the
16 x 16 segments of the detector. The scattered particles of interest stopped in the second or the third
detector. Each silicon detector provided independent
energy-loss information, while the whole telescope provided total energy deposit information. An isotopic
identification of scattered particles was achieved by the~E- E method . The counter telescope with an active
diameter of 92 mm covered the scattering angle up to
about 6 degrees. The scattering angle was determinedby the hit positions in the two PPAC's at F3 and thefirst silicon detector.
De-excitation , rays were measured in coincidencewith the scattered particles. A granular array of
66 NaI(TI) scintillators was placed around the target
and used for ,-ray detection. Each scintillator crystal
had a rectangular shape with a size of 6 x 6 x 12 cm 3
coupled with a 5.1 cm ¢ photomultiplier tube. Theenergy and efficiency calibrations of each NaI(TI) detector were made by using standard 22Na, 60Co, 88y,and 137 Cs sources.
Our data include the first measurement of the B(E2)value for the 2t state in 34Mg. The number of accumulated events for the 28Ne and 32Mg measurementsin the present experiment was 3-10 times more thanthose in previous experiments;I,4) more detailed information on the collective behaviour in these nuclei is tobe obtained. An analysis of the data is now in progress.
References
1) T. Motobayashi et al.: Phys. Lett. B 346 , 9 (1995).

2) T. Glasmacher et al.: Phys. Lett. B 395, 163 (1997).
3) T. Kubo et al. : Nucl. lnstrum. Methods Phys . Res. B
70, 309 (1992).
4) B. V. Pritychenko et al. : Phys. Lett. B 461,322 (1999).

RIKEN Accel. Prog. Rep. 33 (2000).,. Population(.' o f ,Excited States ' in U ristable N llclei '. Prod Heedby the Fragmentation of 36Si
T , Gomi, K. Yoneda, H. Sakurai, S. Shimoura, 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. Takeuchi, Y. X. Watanabe, K. Yamada,
Y. Yanagisawa, K. Yogo, A. Yoshida, and M. Ishihara[com

N~CLEAR REACTION: 9Bee 6 Si,X), Ee 6 Si) = 50 A MeV; MeaSUred(fragment)gamma-]

We measured , rays in coincidence with fragments
produced by the 36 Si+ 9Be reaction at 50 A MeV. Fromthe measured yield of ,-ray lines we extracted the population ratios of excited states in several unstable nuclei. They are related to the reaction mechanism of
the projectile fragmentation, and provide useful information for exploring the possibility of spectroscopic
studies of unstable nuclei.
The experiment was performed in the RIPS beamline. The setup is described in Ref. 1. Figure 1 shows
typical ,-ray energy spectra with a Doppler-shift correction obtained for 180, 22Ne, and 28Mg. Two lines
are observed in each spectrum. They correspond to
the known 2+ --t 0+ and 4+ --t 2+ transitions.
The population ratio for an excited state can be
expresed as
Preliminary

100

x : P(2+)

g
Cl.,'Preliminary<> : P(4 +)

BO

60

40

20

0

5

0

10

6A

Fig. 2. Plots of the population ratios, P(2+) and P(4+),
as a function of ~A. The solid curve represents predictions for P(2+) within the framework of the abrasionablation model, and the dashed curve for P(4+).

1000

P = N "{/c(E"{)

800

Nf

600
400
200

>CD
~

0
C\l

"""
fIl

.~

~
;:j

0

0
1500
1000
500
0

()

1500
1000
500
1000 2000 3000 4000'

where N"{ represents the peak yield of the ,-ray; c(E"{)
the photo peak efficiency as a function of the ,-rayenergy, and N f, the number of identified fragments.
We obtained P(2+) when we counted the peak yieldcorresponding to the 2+ --t 0+ transition, and P( 4 +)for the 4+ --t 2+ transition.
In Fig. 2, the preliminary results of P(2+) and P(4+)
obtained for even-even isotopes with Z = 8- 12 areplotted as a function of the number of nucleons removed from the projectile (~A). The solid curve represents predictions for P(2+) based on a theoretical calculation within the framework of the abrasion-ablation
model,2) and the dashed curve for P(4+). From the experimental data, we found that the population ratios
increase when ~A increases; this tendency is in accord
with the theoretical one. As can be seen in Fig. 2, thepopulation ratio reaches 10% at ~A ~ 5 for 2:+ and~A ~ 10 for 4+.
ReferencesjFig.!. Doppler-corrected ')'-ray energy spectra associated.''with 18d, ' i2 Ne, and 28Mg.

1) K . Yoneda . et al.: RIKEN Accel. fr9g. Rep., 33, ; 70
(2000).
2) M. de Jong et al.: Nucl. Phys. A 613, 435 (1997).

69

RIKEN Accel. Prog. Rep. 33 (2000)

Gamma-·R ay Spectroscopy of the Very Neutron-Rich .Nucleus 34Mg
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
NUCLEAR REACTION: 9Bee6Si, X), E = 50 MeV/nucleon; Measured .fragment,-coin;][ Deduced Ex of 34Mg
We have observed the ,-ray transitions in the very
neutron-rich nucleus 34Mg for the first time. The excited 34Mg nuclei were created by the projectile fragmentation reaction induced by a 50 MeV/nucleon radioactive beam of 36Si.
The experiment was carried out at RIPS. A primary
40 Ar beam of 95 MeV/nucleon with a typical intensityof 60 pnA bombarded a 9Be production target with
462.5 mg/cm 2 thickness to obtain a radioactive beamof 36Si. The 36Si nuclei in the beam were separated
event by event from the main contaminant 37p using
time-of-flight (TOF) information between two plastic
scintillators. The purity of the 36Si beam was approximately 80% and the intensity was around 2 x 10 4 S-1.
A secondary target of 385 mg/cm 2 9Be was placed at
the focal plane of RIPS. The beam lost its energy in thetarget from 50 MeV/nucleon to 30 MeV/nucleon. The
reaction products from the 36Si + 9Be fragmentation
were detected by four sets of counter telescopes in a
2 x 2 matrix placed 56 cm away from the target. Each
telescope consisted of three layors of ion-implanted silicon detectors of 50 x 50 mm 2 effective area and 350 J.lm
thickness, followed by a 1 mm thick Si(Li) detector
with the same size to identify unwanted light particles that punched through the three ion-implanted
detectors. Particle identification was achieved by thetlE-E information from the the first three detectors,
combined with the TOF information between the secondary target and a parallel-plate avalanche counter(PPAC) located 48 cm downstread of the target. A
good resolving power of the detectors enabled us to
identify A and Z for reaction products with Z = 8-12.
Sixty-six NaI(TI) scintillators surrounded the target
to detect, rays emitted from the excited fragments.
Each scintillator crystal was of rectangular shape witha size of 6 x 6 x 12 cm 3 coupled with a 5.1 cm ¢ photomultiplier tube. Their energy resolution was typically
7.5% for a 662 keY ,ray. The high granularity ofthe setup allowed us to measure the angle of the, rayemission with approximately 20° accuracy, enabling us
to correct for the large Doppler shift of v / c ~ 0.3 according to the detector angle with respect to the beam
direction. The total full-energy peak efficiency was calculated to be 18% for a 1 MeV, ray. A lead shield with
5 cm thickness surrounded the NaI(TI) for background
reduction .

70

60
50

>

Q)

40

~

0

~

~
(f)
..j..ol30~

1430keV

;::J
0

U

20

10

OLL~~-LLL~~-L~~~~~~~~UU

o

500

1000

1500

2000

2500

3000

Energy (keV)
Fig. 1. Doppler-corrected )'-ray spectrum in coincidencewith 34Mg, produced by the 40 Ar + gBe fragmentation
reaction.

Figure 1 shows the, ray energy spectrum associatedwith 34Mg identified in the detectors. It was obtained
as a sum of each Doppler-corrected spectrum of all the
NaI(TI) scintillators. As one can see in Fig. 1, twofull-energy peaks were observed. The energies wereprelimnarily determined to be 670 keY and 1430 keY.
The first peak can be tentatively assigned to be corresponding to the 2t --t O;'s. transition, since it is thestrongest and its energy is the lowest in the spectrum.
The energy resolution deduced by fitting the first peakis 80 keY (FWHM), which is mainly due to Doppler
broadening with the finite angular resolution of each
NaI(TI) crystal.
The energy 670 keY is very low compared with thoseof the first 2+ states in the neighbouring nuclei. Using an empirical formura for the relation between the
excitation energy and the deformation parameter, 1)

E(2+) = 1224((,B2)A 7 / 3 )-1 ,the energy of 670 keY leads to a large deformation of 34Mg with ,B ~ 0.7. Within the frameworkof the shell model, the excitation energies of thefirst 2+ ' and the first 4+ state were recently calcu~
lated to be 620 ke V and 2460 ke V, respectively,2)which agree · well with the energies extracted 'in
the present work (670 keV and 2100 keV) , if one
assumes that the second ,-ray peak corresponds todeexitation from the first 4+ state to the first 2+
state. Furthermore, the energy ratio E(4+)/E(2+)
is deduced to be 3.1, which is close to the 3.3

expected for the rotational barid of deformed nuclei.
References
1) D. Guillemaud-Mueller et al.: Nucl. Phys. A 426, 37(1984).
2) Y. Utsuno, T. Otsuka, T . Mizusaki, and M. Honma:
Phys. Rev. C 60, 054315 (1999).

71

RIKEN Accel. Prog. Rep. 33 (2000)

Half"7Life Determination of 44Ti Using a Radioactive Beam TechniqueZs. FUlop, Y. Wakasaya, C. Bordeanu, M. Golovkov, R. Goswami, T. Kato, K. Kimura, H. Kudo, *1
Y . Mochizuki, H. Otsu, A. Ozawa, H. Petrascu, H. Sakurai, T. Suzuki, 1. Tanihata, K. Yoshida,
R. N. Boyd, A. Krasznahorkay,*2 and E . Somorjai*2[Half-life, Nucleosynthesis]
In addition to studies of exotic nuclei, radioactive
ion beam (RIB) technique also proved to be a useful
tool to determine the half-life of 44Ti when a relative
method is used. 1) Here, we propose a novel method tothe fast and reliable absolute half-life determination
and apply it to the same isotope. In order to perform a meaningful analysis of the observed results ofthe E-y = 1157 keY line -characteristic to the decayof 44Ti- in the Cassiopeia A 2) supernova and the recently discovered RX J0852.0-4622/GRO J0852-4642
supernova remnant,3) an accurate determination of thehalf-life of 44Ti is necessary.
Because of the relatively long half-life of 44Ti
( rv 60 y), several years are needed to follow its decay
until the desired accuracy in half-life can be reached.
According to recent measurements,4,5) 2-5 years ofdata-taking resulted in 1- 3% relative errors when the
44Ti half-life was determined relative to that of sources
as 60Co, 22Na, and 207Bi. However, for an absolutemeasurement,6) where the absolute activity of a sample
has been determined several times, a period of 20 years
was needed to reach a similar error level. The availability of 44Ti as RIB offers an alternative method to determine the half-lives via implanting a known amountof 44Ti into a stopper, and to measure the activity relevant to the decay of 44Ti. Gorres et at. 1) measured
the half-life of 44Ti relative to that of 22Na, emphasizing that it is questionable to apply the RIB techniqueto absolute half-life determination because of the low
expected count-rates and the systematic errors.
Our aim was to establish a method that allows anabsolute half-life determination with minimum systematic error and maximum versatility. It is also desirable
that the measurement should give a reasonable error
without years of data-taking. In our approach, thesecondary beam is optimized not for the highest available intensity, but to reach an isotopic ratio where thetime-of-flight (TOF) technique is enough for the separation. Since plastic scintillators can be used for TOF,
the isotopic ratio can also be monitored under highintensity irradiation. Details about the preliminary
tests, secondary beam production, the irradiation andthe off-line activity measurement setup have alreadybeen published elsewhere. 8 ) The 44Ti was produced byfragmentation of 90 A MeV 46Ti on a beryllium target.

*1
*2

72

Niigata University
ATOMKI, Hungary

Through appropriate settings of the fragment separator we achieved a secondary beam intensity of
2·10 5/s without implanting isotopes contributing to
the gamma activity of the stopper. Also, we kept thecontent of 42SC (same A/Z as 44Ti, i.e. TOF determination is not enough to separate this isotope from
44Ti) to a minimum «0.5%).
The separated fragments were implanted into a
1 mm thick plastic scintillator stopper, allowing a lossfree determination of the number of implanted ions.
Behind the stopper, an additional plastic scintillator
served to check the presence of ions penetrating the
stopper. We also investigated the effect of the breakupof the already separated 44Ti ions.
The ,-activity of the implanted sample has been
investigated by a well-shielded high-efficiency HPGE
gamma detector. There is no contamination observedin the gamma spectra of the irradiated sample. The
efficiency determination has been carried out by using 65Zn and 60Co sources, and the effect of extended
sources has also been investigated.
In summary, we have implanted 2.7 x 109 44Ti ions
into the stopper, and during the off-line measurement
the count-rate in the detector relevant to the 1157 keY(44Ti-related) peak was 50 counts/hour. On the other
hand, the measured photopeak efficiency is 1.3 x 10- 2in the used source-detector geometry. Our preliminary
half-life value for the 44Ti is 62.1 ± 1.6 y. The relative error of this method is comparable to the previous
measurements, although only one day of irradiationand two weeks of activity measurement were necessary. Preliminary studies showed that the presented
method can be applied to isotopes 39 Ar and 32Si.
References
1) J. Gorres et al.: Phys . Rev. Lett. 80 , 2554 (1998) .
2) A. F. Iyudin et al.: Astron. Astrophys. 284, L1 (1994).
3) B. Aschenbach et al.: Astron. Astrophys. 350, 997(1999).
4) E. B. Norman et al.: Phys . Rev. C 57, 2010 (1998).
5) I. Ahmad et al.: Phys. Rev. Lett. 80 , 2550 (1998).
6) F. E. Wietfeldt et al.: Phys. Rev. C 59, 528 (1999).
7) Y. Chen et al.: Phys. Rev. C 47, 1462 (1993).
8) Zs. Fiilop et al.: Proc. 'Nuclei in the Cosmos V', editedby N. Prantzos and S. Harissopulos, p. 281 (1998).

RIKEN Accel. Prog. Rep. 33 (2000)

Collective States of Neutron-Deficient Doubly Even Barium Isotopes
K. Uchiyama, H. Sakamoto,* and K . Furuno[B(E2) , Ba isotopes, Boson expansion theory]
The experimental B(E2; ot ~ 2t) values in theneutron-deficient doubly even Xe and Ba isotopes show
significant increase in the midshell region without any
concomitant change in the energies of the low-lying
states. 1,2) Recently, for Ba isotopes , improved experimental results have been reported, and an old compilation of experimental data3) includes a questionable result, which is described below. To provide the systematic behavior correct ly, we recompiled the experimental B(E2; ot ~ 2t ) values of Ba isotopes, and thencompared these experimental data with new resultsfrom a microscopical calculation using t he normalordered linked-cluster boson expansion theory.4)
All available experimental data and our adopted values are given in Table 1. We should mention thatthe value 0.504(71) e 2b 2 reported by Towsley et al.
in Ref. 5 has been ignored, because the description in
Table 1. Experimental B(E2 ; ot ~ 2t ) values in Ba isotopes .
NuclideB(E2) [e 2b 2]

MethodReference'

1220a

2.77(25)
2.77(25)

Delayed Coincidence
Adopted value

P RC46(1992) R6

I2<Ba

1.34(12)1.99(8)2.09(9)2.09(9)Delayed Coincidence
Reco il Distance
Recoil Distance
Adopted value

PRC46( 1992)R6
P RCS2( 1995) 1380
I::P J A2(1998)13

1.28(24)
1.99(32)

Recoil DisLR.oc:eRecoil Dista nce

NPA93(1967)272
pR.eS( 1972) 1658
I'L080(19 79 )345
J I'G 1S( 1989) L85
I' ltC46( 1992)R6
l'HCS4( 1996)R2119

126B.

1.83~g: ~~2.03(15)
1.69(17)
1.69(S)
1.72(5)

Recoil Distance
Recoil DistanceDelayed Coincidence
Recoil Distance
Adopted val ue

1281l.

1.50(32)
1.46(8)1.38(9)1.46(8)

Recoil Dist ance
Reco il Distance
Reco il Dist a nce
Adopted value

PRC5( 1972)1658
NI'A543(1992)589
I' RCS3( 1996) 160G

130Ba

0.7S(19)
1.36( 14)
1.21(38)
1.163(13)

1' 1t109( 1958) 100
NPA94( 1967)177
JPSJ 34( 1973)442
NPA494 (1989)102

l.I7(2f

Coulomb Exc it.ation
Coulomb Exci tation
Coulomb Excit ation
Coul omb E xcita t ion
Adopted value

I32Ba

0.73(18)0.859( 41 )0.859(41 )Coulomb Excitation
Coulomb Exci tation
Adopted value1'1{]09(1958)100
NI'A432(1985)5 14

I3< Ba0.75(25)
0.672 (16)0.700 (15 )0.672(15)0. 665 (6)0.669(5)Coulom b Excita t ion
Coulomb Excitation
Coulomb Excitation

AD DT36(1987)1
PR.C6(1972) 1016
NPA283(1977)526
NPA432(1985)514
NPA494(1989)102

0.53(16)
0.4 18( 11 )0.353(49)0.399(3)0.394(13)Coulomb Excitation
Coulomb Excitation
Doppler Shift Attenuation

OA I 8(4)Coulomb Excita t ion
Adopted value

136Ba

0.406(3)Coulomb Excit a t io n

C-oulomb Excitation
Adopt ed value

Cou lomb Excitation
Coul omb Excitati on

4
N~

3.5

:0-

3

-+
C\J

2.5

A
II

2

+

a

1.5

~

N-

W

CO

1

0.5

o

~~~

__

~~

__

• •

~-L_ _~~~_ _~~60 62 64 66 68 70 72 74 76 78 80 82
Neutron Number

Fig.!. Experimental and theoretical B(E2; ot ~ 2t) values in Ba isotopes. The solid circles express the experimental data and the solid line denotes calculations of
the boson expansion theory.

Ref. 5 contradicts itself; it is thus impossible to judge
whether this value is the result for either 134Ba or for
136Ba. Indeed, this value had been referred to as theresult for 134Ba in Ref. 3; on the other hand, it had
been used as the result for 136Ba in Ref. 6. Although
our newly adopted value of 130Ba is about 9% smaller
than our previous one,2,7) the new value is more desirable from systematic point of view. The difference
between the newly adopted values and the previous
ones is less than 2%, except for 130Ba, as mentioned
above.
The experimental data and calculations based on theboson expansion theory are shown in Fig. 1. The int eraction strengths were changed for each nuclide, but
a common effective charge of 0.550 was adopted forall of the Ba isotopes considered. The calculations arein fairly good agreement with the experimental data
without any serious problems which had appeared inother calculations. 1,7) In addition, it is worth noticingthat the experimental B(E2) values of the 4t ~ 2t
and 6t ~ 4t transitions for 124- 128 Ba could be reproduced with same parameters. The detailed results ofthese new calculations will be described elsewhere.
References

ADNDT36(1987}l
PRC6( 1972) 1016
AD'WT36(1987)1
PItC29(1984)1672
NI'M32(1985)514
I'RC34( 198G)732

t P RC , EPJA , NPA, PLO , J PG, PR, JPSJ and ADN DT mean P hysical Review C, European
Physical Journal A, Nuclear P hysics A, P hysics Letters B, Journ al of Physics G , PhysicalReview, J ournal of the Physical Society of J apan and Atomic Data a nd Nuclear Data Tables,
respect ively.

1) S. Raman et al.: Phys. Rev . C 52, 1380 (1995).
2) K . Uchiyama et al.: Eur. Phys. J. A 2 , 13 (1998) .
3) S. Raman et al.: At. Data Nucl. Data Tables 36, 1(1987).
4) H. Sakamoto: Phys. Rev. C 52, 177 (1995).
5) C. W . Towsley et al.: J. Phys . Soc. Jpn. 34, Suppl.
p . 442 (1973).
6) M. J. Bechara et al.: Phys. Rev. C 29, 1672 (1984).
7) M. Sugita et al.: Phys. Lett. B 440, 239 (1998).

Faculty of Engineering, Gifu University

73

RIKEN Accel. Prog. Rep. 33 (2000)

Production Cross Sections of Light Neutron-Rich Nuclei
from 40 Ar Fragmentation
A. Ozawa, O. Bochkarev,*l L. Chulkov,*l D. Cortina,*2 H. Geissel, M. Hellstrom,*2 M. Ivanov,*3 R. Janik,*3
K. Kimura, T. Kobayashi , A. A. Korsheninnikov, G. Munzenberg,*2 F. Nickel,*2 A. A. Ogloblin,
M. Pfi.itzner,*2 V. Pribora,*l H. Simon,*2 B. Sitar,*3 P. Strmen,*3 K. Summerer,
T. Suzuki, 1. Tanihata, M. Winkler, and K. Yoshida
NU?LEAR REACTIONS; 40 Ar + Be, E rv 1 A GeV; Secondary beams; Production cross-][sectlOns
Since the pioneering experiments at Berkeley,1) projectile fragmentation has been widely used to produce
radioactive isotopes far from stability. Measurementsof the production cross sections ((] F) are important toassess the feasibility of secondary-beam experimentswith them. This work represents the first measurements of (] F from 40 Ar fragmentation at relativisticenergies which extend far into the region of neutronrich isotopes.
We measured (] F from 40 Ar fragmentation by using the FRagment Separator (FRS) facility at GSI. A
primary beam of 40 Ar with an energy of rv 1 A Ge V impinged on a Be target with typically 4.0 g/cm 2 thickness . A secondary electron transmission monitor wasused to determine the primary-beam intensity. At thefirst fo cus at FRS, we placed a scitillation counter tostart the TOF. This detector was also used as an active
monetum slit (~p/p = ±0.6%). At the intermediate
focus, we placed a scitillation counter stack comprising
five scintillation counters. One of them served as a stop
signal of the TOF. The corrected pulse-height data of
the counters gave ~E for the fragments. The magnetic
field in the second dipole gave Bp for the fragments.
Thus , we applied the Bp-~E- TOF method in order to
identify the fragments.
In order to determine (] F , the counting rates of different isotopes obtained from the particle identification spectra were corrected for any transmission losses
in the FRS, for losses due to secondary interactionsin the target as well as in the detectors and for thedead time of the data acquisition. The transmission
losses and secondary interaction losses were estimatedfrom a Monte-Carlo type calculation, a code called
MOCADI,2) where we assumed a Gaussian curve forthe momentum distributions of the fragments. The
obtained (] F are shown in Fig. l.
In Fig. 1, the experimental results are compared tothose previously measured with a C target at relativistic energies at LBL. 3,4) Both results are very consistent. In Fig. 1, our experimental results are also
compared with those from the the empirical parametarization EPAX. 5 ) For nuclei near to the line of beta,01

*2
*3

74

Kurchatov Institute, Moscow , Russia
GSI, Darmstadt, Germany
Comenius University, Bratislava, Slovak Republic

10"
10-6

10-'

10-'0
10-"
10-2

,......,

e
\:)

u..

\

\'\

10-6

~.,

10-'

"':'"

10"
10-6
10"
10-'0

10"' 210-2\10-' 010"' 2
10

12

14

~

B

.,

16

c

12

N

22

16

~

18 20

22

24

26

28

30

A

",

18 20

14

0

.
24

26

28

30

A
Fig. 1. Experimental production cross sections (() F) for
B to F isotopes produced with an 40 Ar primary beam
at 1 A GeV in a Be target. The closed circles show
the present data. The open circles (squares) show theexperimental data previously measured with a C target
at 213 A MeV (1.6 A GeV), respectively. The ()F arecompared to the previous version of the EPAX formula(dashed line) and to the modified version (solid line) .

stability, these quantities are in good agreement. However, for more neutron-rich nuclei , the measured (] Fare
smaller than those from the EPAX prediction. Veryrecently, K. Si.immerer and B . Blank have suggested amodified EPAX formula.6 ) The modified version predicts the measured (] F with better accuracy than theoriginal version.
References
1) D. E. Greiner et al.: Phys. Rev. Lett. 35 , 152 (1975).
2) N. lwasa et al.: Nucl. lnstrum. Methods Phys. Res. B
126 , 284 (1997) .
3) Y. P. Vioggi et al.: Phys. Rev. Lett. 42 , 33 (1979).
4) C. Tull: Ph. D. thesis, LBL -(1990).
5) K. Siimmerer et al.: Phys. Rev. C 42, 2546 (1990).
6) K. Siimmerer and B. Blank: Phys. Rev. C, in press.

2. Atomic and Solid-State Physics

RIKEN Accel. Prog. Rep. 33 (2000)

Positron Scattering by Polyatomic Molecules
T. Nishimura and 1. Shimamura
Theoretical cross sections for elastic scattering of
positrons from Ne, Ar, CH 4 , and SiH 4 targets are reported. The latter two molecules belong to the Td
point group, and the effects of molecular anisotropy
in these collision systems are minimal. The present
work was inspired partly by the experimental elastic
differential cross sections (DCSs) recently reported for
CH 4 1) and Ar2) over a large range of scattering anglesof 30°-135°. The present work is based on the fixednuclei approximation. The interaction potential between a positron and a target is represented in the formof a local potential that consists of electrostatic andpolarization components. For the latter component, aparameter-free model potential is adopted for the smallvalues of the positron-target distance (say, less thanseveral a. u.). This model potential is associated withthe asymptotic form of the dipole polarization potential at the position where the two kinds of potentials
first cross. The wave function of the scattered positron
satisfies a set of coupled differential equations derived
from the Schrodinger equation for the total collisionsystem . By solving these equations, the scattering matrix is obtained from the asymptotic form of the wave
function, and is transformed into the cross sections.
Throughout the present calculation, no positronium(Ps) formation channel is taken into account. Therefore, the present calculations are only carried out below
the Ps formation threshold energy (Eps).
The theoretical elastic integrated cross section(ICS) from the present calculation for Ne is in very
good' agreement with the measured total cross section(TCS)3) (see Fig. 1). As the quantity Eps of eachsystem becomes smaller, however, a disagreement between the theoretical elastic 1CS and the experimental
TCS 3) becomes larger .. The result suggests that theeffect of the Ps formation channels on the cross sections is strong, particularly when the Eps is small. As
for Ne, a minimal 1CS called the Ramsauer-Townsend
mimimum, is seen at around 0.8 eV,and is caused bya phase shift for a dominant partial wave component
being close to an integral multiple of 7r. The minimum
disappears as the absolute value of the dipole polarizability of the target becomes larger, i.e., in the orderof Ne, Ar, CH 4 , and SiH 4 , because the effect of thedominant partial wave component becomes more ambiguous due to a superposition of higher partial wave
components. The present elastic DCS for each target
has a notable minimum at around 40°-50° (see Fig. 2).
For Ar and CH 4 , the shapes of the theoretical DCSs
are generally in good agreement with the measured
ones 1 ,2) which are normalized to the elastic DCSs fromthe present calculations at a scattering angle of 90
0

c:

.~

••, ~ ,., ; ,., ~, .. ~ , .. ,., ~ ,., ~ .+, ! ,., ! ,., ~,., ~ •

en

....

2

u

\

~~

•

I

~

,'

6

8

12

10

Collision Energy ( eV )Fig. 1. Elastic ICSs of positrons from Ne, Ar, CH 4 , andSiH 4 below the Eps (14.8, 9.0, 5.8, and 4.8 eV, respectively). The present calculations for Ne (short dashes),
Ar (long dashes), CH 4 (full), and SiH 4 (chain) are compared with the respective experimental TCSs 3 ) (diamonds, open circles, full circles, and triangles, respectively).

'"7~

N§
'C

~
C

'~
en

0.1

'"e

u

OJ
.~

0.01

~

~

is

0.001
20

40

60

80

100

120

140

160

180

Scattering Angle (deg.)

Fig. 2. Elastic DCSs for Ne (short dashes) and Ar(longdashes) at 5 eV, and those for CH 4 (full) and SiH 4(chain) at 4 eV. Comparisons are made with the experimental DCSs for Ar (open circles)2) at 5 eV andCH 4 (full ones)1) at 4 eV.

We have also found a similarity between the theoretical
DCSs for CH 4 and Ar not only in terms of shape but
also magnitude. This may be attributed to a quantitative similarity between the interaction potentials forthe two systems at intermediate and asymptotic values of the positron-target distance. A theoretical study
on the positron-hydrogen molecule collision taking Ps
formation channels into account is under way.
References
1) D. A. Przybyla et al.: Phys. Rev. A 55, 4244 (1997),
2) S. J. Smith et al.: Phys. Rev. Lett. 64, 1227 (1990).
3) W. E . Kauppila and T. S. Stein: Adv. At. Mol. Opt.
Phys . 26, 1 (1989).

•

75

RIKEN Accel. Prog. Rep. 33 (2000)

Total Cross Sections for Electron and Positron Collisions
with CF 31 Molecules
O. Sueoka,* A. Hamada,* M. Kimura, and 1. Shimamura
Because of the basic importance of the fundamental
understanding of electronic and molecular structures,and scattering processes, for applications in various
fields, particularly to plasma processing, a study on
the total, elastic and inelastic processes of electron
scattering from CF3I has attracted much interest in
recent years. Due to its short lifetime in the stratosphere, this molecule has potential for application inplasma processing as a next-generation process gas. 1)
Therefore, it is essential to establish all cross-section
data for the electron scattering of this molecule bycompiling the existing experimental and theoreticalresults. Furthermore, a comparative study of electron
and positron scattering is expected to provide deeper
insight to the fundamental aspects of atomic andmolecular dynamics in hydrocarbons and the interaction mechanisms. To the best of our knowledge, nocomplete study of total cross sections (TCSs) basedon both electron and positron scattering has yet been
carried out. Hence, we have initiated the present joint
experimental and theoretical investigations on theseprocesses for CF3I to provide comprehensive TCSs
for assessing the magnitudes of other weak inelastic
channels, as well as dynamical information to derivea guiding principle for applications to other plasma
etching gases. The experimental apparatus and themeasurement method of TCSs have been reported
earlier. 2,3) In brief, a 22N a radioisotope of 90 I1Ci andbaked tungsten ribbons were used as the positronsource and the positron moderator for low-energy
positrons, respectively.
For the electron source,slow electron beams were produced after secondary
electrons were moderated by multiple scattering in
the tungsten ribbons. A retarding potential unit
was combined with the TOF system for eliminationof elastically and inelastically scattered projectiles.
The theoretical approach employed is the continuum
multiple-scattering (CMS) method, which is a simple
but efficient model for treating electron scattering from polyatomic molecules. 4 ) Figure 1 presents

Faculty of Engineering, Yamaguchi University

76

,

.
•

CF 31
,:w,"""••• •• • .ee:--CF3140...-..

N

E

(.)
<0

I"
0
...........

•
••

30

•

c
0

:+J

• ••

(.)
Q)

rJ)
rJ)
rJ)

20

•

' ~~?!ffP oe:tPc90 0 • •
0 o.

~

t;

oo

ro

f-

,

0

.....'" c9

0

15

0

•
••
••

10

o.
o.
o.

o

0

0

O~~~I~~~~~~~~~~--~~~~

10°

10 1

102

103

Energy (eV)Fig. 1. Total cross sections of the CF3I molecule following
positron (0) and electron (.) impacts.

the TCSs for both electron and positron impacts with
CF 3I, from 0.7 eV to 600 eV. Novel results can besummarized as follows: (1) The cross section following electron impact has two small, conspicuous peaks
at 8 and 40 eV due to shape resonances, while thatof positron impact shows clear structures above 6 eV
due to positronium formation, followed by direct ionization. (2) Neither cross sections appear to merge,
even beyond 500 e V.
References
1) L. G. Christophorou et al.: J. Phys. Chern. Ref. Data25, 1341 (1996).
2) O. Sueoka and S. Mori: J. Phys. B 19, 4035 (1986).
3) O. Sueoka et al.: J. Phys. B 27, 1453 (1994).
4) M. Kimura and H. Sato: Comments At. Mol. Phys. 26,
333 (1991).

RIKEN Accel. Prog. Rep. 33 (2000)

Simulation of a Diatomic Molecule Colliding with Surfaces
M. Kimura and 1. Shimamura
Collisions of an O 2 molecule with a Ni surface
are studied using a simulation based on the classicalmotion of equations. Taking the Morse potentials
among all the colliding particles, i.e., atom-atom in themolecule, molecule-surface, and surface atom-surface
atom, the simulation is carried out by changing theparameters of the surface temperature, kinetic energy,
and rovibrational state of the molecule. It is clearlyseen for various cases that: (1) the incoming molecule
collides with the surface and bounces back, (2) the
molecule collides and is adsorbed on the surface by giving off its kinetic energy and creating surface phonons,(3) the molecule fragments on the surface upon collision, (4) the molecule penetrates inside the solid, and(5) upon collision, the quantum state (rovibrational
state) of the incoming molecule changes. Study ofthe vibrational excitation dynamics on surfaces has
been an area of active research in the field of surface

-=

Hl

.

.

'

ii t ... =O.1
1.0

I t _ l = 27.0
! t _ r = 0.0; t_v= 0.0l.'~~:. .;~t.
~.

. ( ~!.~, ·· :~t7 ~

.!\~~

.~

'\~

..
i .. ....
., •
i".
;

i

I~
I

,~

'

'

• .,
••
•tp

'ijtr

<~l"

~~.
.~

.~

~

~.
~,

ti

1%
,~

(to

~

.

.~s:~:

\

.~

,~

.~

~
,~

~

'Sf"

•

~

';"

If#.!

I

'

.

,

•

ftIr.U:3

t ..... = 19.051
t_=I.Ot_:I.O;i~·\-:t;::.~~",~:{: .~... ,;~'~.,'~:: t~;:!(.F{S:;c(:7. ;~ ::" ~l.<i:~i'·:'.'!~ ·.• !t~ ~" <"iii 'iii." ;'Ij:'F'"::i'.!t" ~!)'.' ~~~;a :~.l ,:o;) ~·;l:~ ·~.lo ~ l1'-i-(;".!i) ';~':'''';(;'.'qi~" r'~'''''i~+ ·C'!i "r~
1~"UIi:.! ;' :~~;!':l 'i...,Q(}.'1 ' ':)7."''''i~J t\lf{; g: . .!+ji~',:: ~.nr-<:-;: \~:;(";~"'l~;~~; (r'.

Ie' .f.tjI~t~' 'I?~",;ri" ·:r~;(l' <~(~:" \::1ff~ ::.t.,.~:" ;,;~.rrtt;.. p~;§~ /'I~I,'l)- I~'iIic)~')!S1 (~::;);I C~lt;' ;:J'~;gt.)!;Jy.~'J? 'Q:Ci~ ; c.~ ~,~~l-: :i,~~~J; .:~:{.~\

Fig. 2. The same as in Fig. 1, but the incident energy of
the 02 molecule is 0.1 eV. The 02 molecule is adsorbedon the surface giving off its kinetic energy a nd creating
surface phonons.

"r.:i

.:

•

_=1.0

teIIPS = 1.6~

Fig. 1. Simulation of an 02 molecule colliding with an Ni
surface in which the O 2 molecule has a collision energyof 1 e V. The incident O 2 molecule is reflected from thesurface and leaves the field.

sciences as well as in applied fields. Vibrational excitation is governed sensitively by the characteristics ofthe potential energy surface and by the energy transfer
between the electronic and vibrational degrees of freedom. Since the quantum of the internal vibrational
excitation of O 2 is approximately threefold the Debye
energy of Ni, the scattering of O 2 of the Ni surface isakin to the scattering of a hard ball on a soft wall.
This leads to phonon creation at the surface in the
scattering event, but not to O 2 stretch vibrations. The
experimental results indicate that vibrational heating
occurs: The ratio of the excitation intensity for v =1 to that for v = 0 is approximately a factor of three
above the simple Boltzmann factor. We present representative examples of the simulation for this collisionsystem. (Figs. 1 and 2)

77

RIKEN Accel. Prog. Rep. 33 (2000)

Radiative Electron Capture of Swift Heavy Ions
into the Continuum StateT. Azuma, T. Ito, Y. Taka b ayas hi , K. Komaki, T. Kambara,
Y. Kanai, Y. Nakai, T. Kojima, and Y. Yamazaki
In heavy-ion-solid collisions, target bound electrons
have a chance of being captured into the continuum
state of projectiles satisfying energy and momentum
conservation by emitting photons. This process iscalled "radiative electron capture into the continuum
state (RECC)" as an analogy to radiative electron capture into the discrete bound state (REC), where discrete X-rays are emitted. The RECC process is accompanied by the emission of continuum X-rays witha maximum edge energy corresponding to the energyof electrons of the same velocity as the projectiles. The
resultant electrons in the continuum state travel in theforward direction, and a portion of them are expected
to emerge as "convoy" electrons with a cusp-shaped
energy peak after passing through the solid target. Understanding of the convoy electron formation following
the RECC process is very limited, although it is a fundamental process. We investigate it through the coincidence measurement of the spectra of emitted X-rays
and cusp electrons.
Bare Kr 36 + ions of 36 and 70 MeV/nucleon passed
through a carbon foil tilted by 45° from the beam direction. Emitted X-rays at the collisions were observed
either by a HPGe or Si(Li) detector located at an angle of 90° from the beam direction. Secondary electrons were measured using a compact magnetic analyzer coupled with a channeltron-type electron detector. The charge distribution of emerged projectiles wasmeasured using a combination of a magnetic analyzer
and position sensitive detectors at the downstream endof the beam. The signals from the charge distributionof the projectiles, X-rays, and secondary electrons wereaccumulated in a list mode.
The X-rays emitted from REC into the K- and Lshell, the continuum X-rays from RECC, and the characteristic X-rays of the projectiles on the shoulder ofthe curve for the RECC component were observed asshown in Fig. 1. The characteristic X-rays are emitted following capture of target electrons into the L or
higher states of the projectiles. Although the crosssections of all processes decrease with higher projectile
energy, Vp , the intensities of REC and RECC decrease
more slowly (ex Vp- 5 and ex Vp-2) than those for nonREC processes (ex V;l1). Therefore, X-rays emitted
from REC and RECC are more clearly observed in the
spectra for higher projectile energies. Concerning thesecondary electron spectra, we clearly observed a binary encounter electron peak for both projectile energies. A cusp peak at the equivelocity of the projectiles
is noticeable only for 36 Me V /nudeon Kr 36 + ions, as

78(a) X ray for 36 Me V In KrJ6 +[xl04 ]'" lOS~=.Q~104r'-------------------------------~.0(b) X ray for 70 MeV/n Kr J6 +

'c;;

=
~ 10

.s

3

\~
K,
K.REC
'-1:~ -1'~~ .. ~.~~EC / \\REC'C~\": .

~tt:-<.:y . :.: ,'. : '10o~~~~~~~~~~~~~~~~

o500

Channel

1000

1500

Fig.!. X-ray energy spectra for Kr 3 6 + ions of (a) 36 and (b)70 MeV/nucleon passing through a 85 J1-g/cm 2 carbon
foil. Detector efficiency is not taken into account.

Secondary Electron for 36 MeV/u Kr36 +\",,",\

103~~~~~~~~~~~~~~~~

0.05

0.1

0.15

0.2

0.25

0.3

0.35

Electron momentum [arb. unit]

Fig. 2. A secondary electron energy spectrum for Kr 36 +ions of 36 Me V / nucleon passing through a 85 J1-g/ cm 2
car bon foil.

shown in Fig. 2, due to the larger capture cross section.
Considering the projectile energy dependence for
X-rays and cusp electrons, the coincidence experiments are suitable at the projectile energy of
36 MeV /nudeon. We are now preparing to carry out
coincidence measurements by applying a large acceptance angle Si(Li) detector to obtain a higher coincidence rate.

RIKEN Accel. Prog. Rep. 33 (2000)

Fullerene-like Fragment Ion Production in Fast Ion-C 6o Collision
Y. Nakai, T. Kambara, A. Itoh, H. Tsuchida, 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, that is the internal energy of the precursor of fragmentation. We reported that high-energy
deposition by fast heavy ion impact causes only multifragmentation. 1) On the other hand, in low-energy deposition by electrons, atoms and collisions with thesurface, C 60 emits small neutral clusters in a few microsecond or longer time scale after excitation.2- 5 ) In thelatter 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 of 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 under the WileyMcLaren spatial-focusing condition to obtain information on the fragmentation mechanism. A beam of
10 MeV He 2 + and 25 MeV C 6 +, provided by the RILAC, passed through a C 60 vapor target. The electrons
extracted from the collision region were used as thestart signal of the TOF measurement. The TOF spectra were obtained using a multi-hit time-to-digital converter. We can separate the peaks of c~t(q = 1,2,3)
which contain different amounts of 13C as shown in
Fig. 1.
In Fig. 1, TOF peaks of c~t (q = 1,2,3) generated
in the collision with the He 2 + beam are shown. Thesepeaks are asymmetric. We also show the TOF spectra
obtained by Monte Carlo simulation for c~t ~c~t +C 2
(q = 1,2,3) with a lifetime of fragmentation and a
0.4 eV kinetic energy release.7) These tails at longer
TOF are reproduced by simulation with a fragment
lifetime of 2.0 f.1sec, 1.75 f.1sec, and 1.1 f.1sec, respectively. This indicates that the internal energy ofdelayed-fragment precursors increases with increase of
the charge state because the activation energies of theemission of C 2 from c~t (q = 1,2,3) do not depend on
the charge state within the experimental uncertainty. 4)
However, the peak shape in the shorter TOF region can
not be reproduced by simulations with a single lifetime
component.
The peak intensities for doubly and triply ionizedfragment ions decrease more rapidly towards a smaller
fragment ion in the collision with He 2 + than C 6 +whereas the intensity ratios for singly ionized fullerene-

200
CZl

150

- lifetime =2.0Jls
Experiment.... Experiment*0.004

+-'

§ 100
o

U

CZl

+-'
~

;::::l0U5013850 13900 13950 14000 14050 14100 14150 14200 14250
800•- - lifetime = 1.75JlS
600• Experiment.... Experiment*0.03400••~,..-....
t\ C602+ - >C 582++ C 2
200
I
/'

.

'.

0
9800
500
400
CZl

+-'

300

9850
9900
- - lifetime = 1.IJlS
Experiment............. Experiment*0.1

9950

10000

10050

~

;::::l

0

U

200
100
0
8000

8050

8100

8150

8200

TOF (ns)Fig. 1. TOF peaks for C;t,H,3+ generated in the collision
with He 2 + are shown. The solid circles represents experimental data. The solid lines represents the resultof Monte Carlo simulation. The dotted lines represents
experimental data showing TOF resolution.

like fragment ions are almost constant. The asymmetric peak shape of fullerene-like fragment ions areobserved in both cases. These results indicate that theinternal energy distributions of the parent C 60 ion ofmultiply ionized fullerene-like fragments are different
between He 2 + impact and C 6 + impact, but that theirproduction mechanisms are similar.
References
1) Y. Nakai et al.: J. Phys. B: At. Mol. Opt. Phys. 30,

2)
3)
4)
5)
6)
7)

3049 (1997).
M. Foltin et al.: J. Chern. Phys. 101, 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).

79

RIKEN Accel. Prog. Rep. 33 (2000)

Isotope Shifts between He-like 12C and 13C Ions
S. Ozawa, T. Ariga, N. Inabe, M. Kase, 1. Tanihata, M. Wakasugi, and Y. Yano
With the ultralow-background photon detection system which we previously designed,1,2) we measured theisotope shifts between He-like 12C and 13C ions in the
1s2s 3S 1-1s2p 3P O,1,2 transitions.
A NEOMAFIOS 8 GHz ECR ion source which
was placed in. the RILAC terminal produced pos12C ions were accelerated to
itive carbon. ions.
0.9 MeV/nucleon by RILAC and stripped by a carbon foil with a thickness of 10 J-Lg/cm 2 . 13C ions wereaccelerated to 0.6 MeV/nucleon before being strippedby the carbon foil. Then 4+ charge state ions weredirected to the experimental area. One percent of all

1s2p 3 p

1s2s 3 S=r~27nml'

T300ev----~oFig. 1. Level scheme of He-like carbon ions.

j227.155

227 180 }--~---:-:-~-2~
37-...J.650--7\JlK/n>'~ 1"/J C

O.6M.Vlu

Isoto;:Shijt

227.18 '/235.370

235.395I

235.420

Wavelength (nm)Fig. 2. Fluorescence spectra of the transition from 3S 1
to 3P2. These four resonance spectra were measured
separately.

80

IsotopeJ

Energy(cm- 1 )Reference 3 )(cm- 1 )

12C4+

0
1
2

43899.749(30)43887.173(19)44023.404(13)

43899
43886
44022

13C4+

0
1
2

43901.556( 41)43889.133(26)44025.207(18)Isotope shift012-1. 807(51)-1.960(32)-1.803(22)Transition

12C_13C

He-like ions are in the 38 1 metastable state and havea 200 ms lifetime. The level scheme of He-like carbon
ions is shown in Fig. 1. A laser beam excites ions in
the 38 1 state and induces fluorescence from the 3P O,1,2
states. To reduce the uncertainty in the absolute ion
beam velocity, each transition energy was measured by
two laser beams which propagate in the directions parallel and anti-parallel to the ion beam. For the wavelength calibration of the laser beam , the absorption
lines in Te2 were measured simultaneously.
According to the Doppler-shift formula, the absolute energies Eo for each transition are determined
as Eo =
EpEap, where Ep and Eap are the resonance energies for the parallel and ant i-parallel laser
beams, respectively. The relationships between theresonance wavelength by the parallel and ant i- parallellaser beams are shown in Fig. 2. Figure 2 also illustrates the isotope shift. The measured absolute energies and the isotope shifts in each transition are shownin Table 1.

.J

Parallel Laser Lli.parauelLase

c............_--:---=:--~~ V 130

Table 1. Transition energies from 3S 1 to each level of 12C
and 13C. Values in parentheses indicate 10'.

References
1) M. Wakasugi et al.: Phys. Scr. T 73 , 70 (1997).

2) M. Wakasugi et al.: Nucl. Instrum. Methods Phys. Res.
A 419, 50 (1998).

3) C. E. Moor: Atomic Energy Levels, NBS, Washington
D.C., p. 30 (1949).

RIKEN Accel. Prog. Rep. 33 (2000)

Foil Ageing Problems In Beam-Foil Spectroscopy Continued
R. Hutton, Y. Zou, S. Huldt , 1. Martinson, K. Ando, and H. Oyama
In a previous article l ) we discussed an effect which
seems to have overlooked detailed study but , however,which is very important to the methods of beam-foil
spectroscopy. The effect is the change in light intensity
in a given spectral line as a function of the exposure
time of the foil. This effect had been discussed previously by Soerensen. 2 ) It has been long known that the
charge state fraction after the foil interaction changes
as function of time, due to foil thickening for example.
However we observe that the light intensity in certain
spectral lines changes at a rate much faster than thechange in the charge state balance, see Fig. 1. Thishas been found to depend on the particular ion andenergy being stripped/excited by the foil. In the previous report we discussed a limited amount of data,
i.e. 0.4 MeV /u Ne and 0.4 and 2.5 MeV /u Mg. In thisreport we will discuss new data showing the foil ageing
effect to be more difficult to deal with than previously
thought. The number of elements for which data isavailable has been increased to cover Ne, Mg, AI , Fe,
Kr and Nb. In Fig. 1 the effects of foil ageing on lines
from 0.8 and 2.5 MeV /u Al are illustrated. The Li-likeresonance lines, (28 2Sl/2-2p 2 Pl/2 ,3/2) , decrease in intensity at both beam energies, however the decrease isslower for the lower energy beam. This is opposite towhat one may expect , for example the foil will breakquicker at the lower beam energy. Also shown in Fig.
1 is the line resulting from 5-6 transitions in the Helike ion. This is only seen for the 2.5 MeV /u beam
as there is a very small fraction of He-like ions at thelower energies, Here a slight increase in line intensity
is observed. Similar, but on a much weaker scale, wasseen for 2.5 MeV /u Mg. For the heavier beams studies
so far , (Fe, Kr and Nb), there has been little or no noticeable effect of the foil age on the light intensity. The
effect of light intensity changing as a function of foil
exposure time has been confirmed by data obtained at
the university of Lund using much lower energy beams
and thinner foils.3) Thus with the existing amount ofdata it is not possible to know in what experiments foil
ageing will be a problem, much more data is needed.

o

45

o
o

40

2.5 MeV/u
Li-like line (11.4 h)

0.8 MeV/ul>.
Li-like line (52.7 If)

o

20

o

15

He-like line
10L-~~~~~--~~--~~--~-J

2

4

6

10

12

14

16

18

20

22

Time (h)Fig. 1. This figure shows that although the Li-like 2s-2presonance line intensity decays as a function of the foil
exposure time the intensity of the 5g-6h He-like transit ion increases (at least at 2.5 MeV lu). Also seen is thatthe 2s-2p intensity decays slower for the lower energy
beam , maybe in contradiction to what one may imagine as foils usually last longer for higher beam energies.
The "h" refers to hours of foil expose to the beam andcomes from a single exponential fit to the data, this fit isdone only for purposes of comparing numbers and has
no physical significance as far as we know. The lightintensity has been normalised to charge collected in agiven time.

References
1) R. Hutton et al.: RIKEN Accel. Prog. Rep. 32 , 95
(1999).
2) G. Soerensen: 1975 Beam Foil Conf., Tenn. , USA,
Plenum Press, p. 165 (1976).
3) 1. Kink: private communication.

81

RIKEN Accel. Prog. Rep. 33 (2000)

Time Delayed Spectral Lines In Beam-Foil Spectroscopy
R. Hutton , Y. Zou , S. Huldt , 1. Martinson, K. Ando, and H. Oyama
It has long been known that spectral lines can be observed at large distances behind the exciter foil used inbeam-foil spectroscopy. This has been observed mostdrastically for Li-and N a-like ions. However, the limit
as to how far spectral lines could be followed has been
set by the noise of the detector. This is still true in the
spectra to be discussed here, except we are now using
a low noise CCD detector system and have been able
to follow spectral lines over a time scale of 100 lifetimes, or more , of the radiating level. Of course thefact that radiation can still be observed is due to cascade re-population of the upper levels. This illustrates
the already known fact that very high n, l states are
populated by the beam-foil interaction mechanism. In
Fig. 1 we compare data taken for a beam of 2 MeV /uNb after ionisation/excitation by a thin carbon foil.
The spectra are recorded with 0 and 200 mm separations between the spectrometer entrance slit and thefoil position. These separations correspond to time delays of 0 and 10 ns respectively. We should point out
here that the lifetime of the 3p 2 P3 /2 level for Na-like
Nb is only 0.029 ns. 1 ) For the 2 P3 / 2 level 10 ns represents a time delay of 340 lifetimes, however , it is clearthat it is still possible to observe this line, at 135.14 A,of course this is because of cascade re-population of theupper level from the high n, l states. Also seen is the
3p 2 P 3 / 2 -3d 2 D 5 / 2 line at 131.7 A. However, the interesting thing now is that lots more lines are seen in the
delayed spectra and not all of these can be assigned toallowed transitions. It may now be possible to identify
slow decaying lines like E2 and M1 transitions in beamfoil spectra due to the low noise offered by the CCD
detector. Moreover the well known allowed transitions
can be used to calibrate the spectrometer.

82

7

10 ns delay

foil zero2

90

100 110 120 130 140 150 160 170 180

wavelenght, A
Fig. 1. Beam-foil spectra for 2 MeV lu Nb ions take withtwo different time delays , 0 (foil zero) and 10 ns. It isseen that lines beyond around 150 A are much more
prominent in the delayed spectra. The 10 ns delayed
spectrum was recorded with a much longer time integration (4 hours) than the foil zero spectrum (1 minute),
and the data intensity normalized for display purposes,
hence different intensity scales.

References
1) R. Hutton et al.: Phys. Rev. A 51 , 143 (1995).

RIKEN Accel. Prog. Rep. 33 (2000)

Spectroscopy of High Z Spin-Aligned States
R. Hutton, Y. Zou, S. Huldt, 1. Martinson, K. Ando, and H. Oyama
The structure of spin-aligned states is best known
for fairly low Z Li-like ions where the ls2s2p 4 P5/2
level is metastable against X ray decay and Coulomb
auto-ionisation. However, there is a Breit induced
part to the autoionisation which is quite strong evenfor moderatly charged ions in the Li I sequence. 1)
There is a similar situation in Na-like ions where the
2p 5 3s3p 4 D7/2 level is also metastable. In this casethe Breit induced autoionisation is not so dominate
as in the Li-like case and the 2p 5 3s3p 4 D7 /2 levelremains long lived even for very highly charged ions,2)e.g. the 4D7/2 lifetime for Na-like Xe is predicted
to be 2.32 ns. 2 ) The metastability of this level wasdemonstrated using electron spectroscopy3) however as yet no lifetime measurement exists. In a
recent work the 2p 5 3s3d 4 F9/2 4) level was studied
for a number of elements in the Na I sequence
using VUV photon spectroscopy.
This level isalso metastable with regards to X-ray and auger
decay but it has an allowed El transition to themetastable 2p5 3s3p 4 D7/2 level. After the identification of the 2p53s3p 4 D7 /2-2p53s3d 4 F9/2 transition anumber of other VUV transitions within the coreexcited complex were identified for Na-like Sand Cl. 5 )In this work a few transitions within the core-excitedconfigurations of Mg-like ions will be examined for anumber of elements in the Mg I sequence. The ions investigated here are S V, CI VI, Ar VII, Ti XI, Mn XIV,Fe XV, Co XVI, Ni XVII and Cu XVIII. The data for
Ti, Fe and Ni have been recorded at RIKEN using the
RILAC accelerator. The other data come from various
other beam-foil laboratories (Lund, Bochum and Argonne National Lab.) and a fuller report is being prepared for publication. 6 ) The transitions of interest are
betweent the 2p 5 3s3p2 and 2p5 3s3p3d configurations,where again the maximum j level is the one giving rise
to a VUV decay channel.
References
1) M. H. Chen et al.: Phys. Rev. A 26, 1441 (1982).
2) M. H. Chen: Phys. Rev. A 40, 2365 (1989).
3) D. Schneider et al.: Phys. Rev. A 40, 4313 (1989).
4) C. Jupen et al.: J. Phys. B 21, L347 (1988).
5) C. Jupen et al.: Phys. Ser. 42, 44 (1990).
6) R. Hutton et al.: Manuscript in preparation.

83

RIKEN Accel. Prog. Rep. 33 (2000)

High-resolution Soft X-ray Study of Ne Hollow Atoms Createdby a Microcapillary Target
S. Thuriez , Y. Iwai, Y. Kanai, H. Oyama, R. Hutton, H. Masuda, * and Y. Yamazaki
This work presents the first high-resolution soft Xray study of the interaction of highly charged ions withmicrocapillary targets. A micro-capillary target consists of many 100-nm-diameter and 700-nm-long capillaries. For this experiment we used a beam of 5 ke V / q
Ne 9 + ions from a 14.5 GHz ECR ion source (Caprice).
Figure 1 shows the spectrum obtained after 0.2 ns fromthe capillary target as compared with a typical spectrum obtained when Ne9 + ions impinge on a flat surface. When we changed the target from a flat surface
to a bundle of capillaries, a drastic change in the Xray spectra and thus in the electronic population of theexcited state is observed. Such a shift toward high energies for the microcapillary target is consistent withan interaction above the surface. 1)
Figure 1 shows three peaks which are observed in theenergy range of our spectrometer, after the beam hasinteracted with the microcapillary target. The maximum of the main peak between channels 48 and 49 has
an energy of 913.3 ± 1.3 eV. It may correspond to thepure helium-like 18o- 3P 1 transition at 914.9 eV, which
may be shifted in energy by the effect of spectator electrons.
The peak maximum at channel 46 (Fig. 1) of energy

Channel number
20

30 40

50

60

70

80

140

"

? ~ ~----~------~~'§ 100
~

"-'

100

'" ,
?

,-., 120

.0

90

Q

(l)

~

_

-e - -

Flat surface

80

0'00 60
I:

B
I:

40

o~~~~~~~~~~~~~

996

940

889

842

799

X-ray energy (eV)Fig. 1. Typical spectra emitted from microcapillary andflat surface targets.

School of Engineering, Tokyo Metropolitan University

84

10 ~~~~~~~~~~~~~~

o

0.2

0.4

0.6

0.8

1.2

1.4

Time (ns)Fig. 2. Total photon emission after the passage of Ne 9 +ions through the microcapillary as a function of thetime after passing through the target.

919 ± 1.3 eV may correspond to the He-like 1S0_1 PI(922 .1 eV) , again possibly shifted by the effect of spectator electrons.
The peak maximum at channel 56 corresponds to anenergy of 894.4 ± 1.3 eV. For Ne 7 +, 1s2s2p 4p states
have a long lifetime: 0.4 ns for 4P1/2, 0.6 ns for 4P 3 / 2
and 12 ns for 4P 5 / 2. The dominant decay channels are
4P 1/ 2 ---+ 1s22s 28 1/ 2 and 4P 3 / 2 ---+ 1s 22s 28 1/ 2 withthe emission of a 895.0 eV photon. 2) The line that wemeasured may originate from this decaying scheme. It
is also consistent with the fact that the observation
point is within 0.2 ns of the target end.
We have also measured the total photon emission as
a function of the distance from the target (Fig. 2). The
time resolution, To (Fig. 2) of the spectrometer is 0.2±
0.01 ns. We observe different lifetime components, oneof which is very long (longer than about 1.4 ns). Thisis consistent with previous measurements performed at
low resolution. 2)
References
1) J . P. Briand et al.: Phys. Rev. A 53, R2925 (1996).
2) Y. Yamazaki et al. : J . Phys. Soc. Jpn. 65, 1199 (1996).

RIKEN Accel. Prog. Rep. 33 (2000)

Angular Dependence of Scattering Intensity in
C + + He ~ C 2 + + He 2 + at Collisional Energy of 120 e V / q
4

M. Hoshino, M. Kitajima, Y. Nakai, Y. Kanai , and Y. Yamazaki

Very slow collisions in ion-atom and ion-molecule
systems are interesting because the angular differential
cross sections are more sensitive to the shapes of active potential curves at lower collision energies. Since
it is difficult to produce a very slow and well-collimatedhighly charged ion beam below about 200 eV /q, where
q is the charge state of the projectile ion , experimental studies in this energy range have been fairly limited. Recently, we have developed a crossed-beam experimental setup for angle resolved energy gain spectroscopy in very slow collisions between highly charged .
ions and atoms or molecules. We utilize the ion beamfrom the 14.5 GHz Caprice electron cyclotron resonance (ECR) ion source at RIKEN.1)
Figure 1 shows the angle-dependent scattering intensity for double electron capture for 120 eV /q
C 4 + (ls2) + He ~ C 2 + (ls22s2) + He 2+. Only small contributions from other final states of C 2+ + He 2+ havebeen observed in the energy gain spectrum. Energy
and angular resolutions are estimated to be 0.75 eV /q
and 0.5 0 , respectively. It is estimated that the statistical uncertainty for each scattering intensity is lessthan 10%. Weak Stueckelberg angular oscillations,which result from interference between several outgoing waves with different scattering paths, are seen in
the experimental data.
Charge exchange processes in C 4 + + He collisions
have been widely studied above 200 eV / q. All of
the experimental and theoretical studies have shownthat the most dominant process above 200 eV / q is
the C 4 + (ls2) + He ~ C 2 + (ls22s2) + He 2+ process,which was explained by a two-state curve crossing
model. Barany et al. have measured differential crosssections for C 4 + (ls2) + He ~ C 2+ (1s22s2) + He 2+
at a collision energy of 380 eV /q ,2) which enabled
Boyed et al. to determine the diabatic coupling
potential for the double electron capture process inthis system. 3 ) We have applied this two-state diabatic
coupling potential for our experimental conditionand calculated the differential cross section. The
results are shown in Fig. 1 by curves. It is foundthat the results of calculations derived form thepotential estimated at 380 eV / q do not reproduce
the present experimental results at 120 eV /q. This

/1
/ \
1\

I
I
I
I
I
I
I

120 eV/q (480 eV)

I
I
I
\
I
I
I

I

I
I
I
I

I
I

• !
I

•

I

•
o

••

8

Scattering Angle SLab (deg.)
Fig. 1. The angular dependence of the scattering intensity
for the C4 + (1s2) + He ~ C2+ (1s22s2) + He 2+ collisionobtained at a collision energy of 120 eV /q (e). Calculated cross sections using the diabatic coupling potential for the C4 + + He system (- - -) and those convoluted
with the angular resolution of ±0.5° (-) are shown
together.
shows that potential curves derived from experimental
data at higher energies are not accurate enough. It
should be noted that not enough is known about interaction potentials between highly charged ions andatoms even in the case of extensively studied systems,
such as the C 4 + + He system. Experimental studies
over a wide collisional energy region, especially at very
low energies, are expected to reveal further informationon collisions between highly charged ions and atoms or
molecules.
References
1) M. Kitajima, Y. Nakai , Y. Kanai, Y. Yamazaki, and Y.

Itoh: Phys. Scr. T 80, 377 (1999).
2) A. Barany et a1.: J . Phys. B 19, L427 (1986).
3) R. Boyd et a1.: J. Chern. Phys. 106, 6548 (1997).

85

RIKEN Accel. Prog. Rep. 33 (2000)

Acoustic Emission Following Fast Heavy-Ion Irradiation of Solids
T. Kambara, Y. Kanai, T. M. Kojima, Y. Nakai, Y. Yamazaki, and K. Kageyama
We observed, for the first time, acoustic emission up
to about 2 MHz from solid materials (metal, oxide andalkali-halide) after short pulses of high-energy heavyions. The objective of this work was to study in realtime the transient deformation caused by fast heavyions, which deposit kinetic energy in the material byelectronic stopping. A Xe-ion beam was accelerated
by the RILAC and the RIKEN Ring Cyclotron up to
26 Me V I u and was guided to an experimental beamline. The beam was chopped after being extracted
from the 18-GHz Electron Cyclotron Resonance (ECR)
ion source to short pulses whose width was shorter than
1 f-.Ls. Since the elastic vibrations in our samples lasted
as long as a few milliseconds, the interval between the
beam pulses was chosen to be longer than 10 ms. The
shortest pulse which we obtained consisted nearly of asingle bunch with a length of about 3 ns. The numberof ions in each pulse was 10 4 - 10 5 depending on thepulse width. Details about the short-pulse generation
are described elsewhere. I)
The beam was then guided to a vacuum chamberwhere the irradiated sample was mounted. The beam
spot size on the sample was about 4 mm x 4 mm.
The sample materials were single crystals of Ab03,
KCI, and metallic polycrystalline Al with a common
dimension; 40 mm long, 10 mm wide and 5 mm thick.
According to calculations with the TRIM code,2) the
range of the ions in the samples is between 170 f-.Lm and
380 f-.Lm, which is much smaller than the sample size.
Therefore all of the ions were stopped in the material
near the incidence surface.
The ultrasonic signals were detected by two piezoelectric ultrasonic sensors equipped with head amplifiers (Fuji Ceramics, M304A). The sensor3) is highly
sensitive to longitudinal waves up to about 2 MHz
and exhibits the highest sensitivity at about 300 kHz.
The ion beam was incident perpendicularly to the
40 mm x 10 mm face of the sample, and two sensors at
both ends of the sample detected the acoustic signals
propagating perpendicularly to the beam direction. A
digital oscilloscope recorded the waveform of the acoustic signals for each pulse of the incident beam.
Figure 1 shows the acoustic signals from a single
crystal of A1 20 3. The acoustic signals have oscillatory
structures whose frequencies distribute up to aboutl.3 MHz. T~e frequency distribution is affected by
the resonant vibration frequencies of the sample andthe characteristics of the sensors. The acoustic signalsof the Al 20 3 have an amplitude lower than that ofmetallic AI, while those of KCI have the highest amplitude. The signal-propagation velocity in the sample
was estimated from the arrival-time difference between

86~ 0.01
<!J

tll)

;s

c

o----.. . .

>

"50..
"5 -0.01

o-O.020!:--~---,l10=----'---2::l::0-~-::3...,..0-'----:'40

Time (Ils)Fig. 1. Acoustic waveform of a single-crystal Ab03 sample irradiated by a nearly single- bunch pulse of theion beam. The displayed waveform is an average over
100 pulses.
5'c'"::I 4-e-S 3
<!J

]

2

0..
E 1

-<

0
0

• O.4MHzo O.3MHz+ 0.6MHz

~

.~9

•

~

t#~;
++++~.~~
•

•

0

+

+

+

+ +

20
10
4
Pulse Intensity (10 ions)30

Fig. 2. Amplitudes of the Fourier components of the acoustic signals observed for an Ab03 single crystal plotted
as a function of the intensity of the ion pulse.
the two sensors as a function of the irradiation position. The result for Al 20 3 single crystal was about
10 4 mls which was in good agreement with the speedof the longitudinal wave estimated from the modulus
of elasticity.
We have studied the frequency spectra of the acoustic signals from the Al 2 0 3 sample as a function of theion-pulse intensity. The amplitude spectrum has peaks
around 0.3, 0.4 and 0.6 MHz. The amplitude of theFourier component is plotted in Fig. 2 as a function of
the ion-pulse intensity. The amplitudes of the Fouriercomponents are found to be nearly proportional to theion-pulse intensity, indicating a linear increase with thetotal energy deposited in the material.
References
1) A. Yoneda and T. Kambara: RIKEN Accel. Prog. Rep.
33, 203 (2000).
2) J. F. Ziegler, J. P. Biersack, and U. Littmark: The Stop ping and Range of Ions in Solids, (Pergamon Press, New
York, 1985).
3) M. Shiwa, H. Inaba, and T. Kishi: J. JSNDI 39, 374(1990).

RIKEN Accel. Prog. Rep. 33 (2000)

Defect Production via Electronic Excitation in Oxide
Superconductors Irradiated withHigh Energy Heavy Ions
N. Ishikawa, Y. Chimi, A. Iwase, N. Kuroda, O. Michikami,* H. Wakana,* and T. Kambara
When oxide superconductors are irradiated withhigh-energy heavy ions, and the energy transferred tothe electrons of the target is high enough, columnar
defects are created along the ion paths. The creationof such -defects results in an increase in electricalresistivity, and this increase strongly depends on thesize of the columnar defects and the inside resistivity(resistivity inside the columnar defects).l) In order
to investigate the defect production mechanism, theresistivity has been measured for ion-irradiated oxide
superconductors. Oxide superconductor EuBa2CU30y(EBCO) thin films were prepared by the rf magnetron
sputtering method and were irradiated with various
ions in the energy range from 125 MeV to 3.8 GeV.
The irradiating ions were 125 MeV 79Br10+ produced
from a tandem accelerator at JAERI-Tokai (Japan
Atomic Energy Research Institute; Tokai Establishment) , and 0.7 GeV 84Krll+, 3.5 GeV 136Xe31+, and
3.8 GeV 181Ta37+ from the RIKEN Ring Cyclotron.
All irradiations were performed at a fixed temperatureof 100 K. The values of 6.p/ Po were measured insitu as a function of ion fluence , 4> , at 100 K by thestandard four-probe method, where 6.p is the change
in resistivity and Po the resistivity before irradiation.
Generally the electronic stopping power, Se , which isdefined as the energy transferred from the irradiating
ion to the target electrons per unit path length , isaccepted as one of the characterization parametersof the defect production process. However, in theprevious -study, ion-velocity dependence in defectproduction has been observed even for the same Se
value. 2 ,3) In this report, we propose an alternative
parameter for describing defect production; the primary ionization rate is represented by dJ /dx, where
J is the number of target atoms primarily ionizedby .the irradiating ion and ' x is the path length of
the irradiating ion. 4,5) Figure 1 shows the change
in resistivity as a function of ion fluence in EBCO
irradiated with ions with the same dJ / dx value.
Irradiation with the same dJ / dx value results inalmost the same resistivity-fluence curve. Therefore,
the primary ionization rate, dJ /dx, is a much better parameter than the electronic stopping power,

Os

I

...

00
0 0 0.84
0
00
00
00
00

1.0o

a...
----..

a..
<l[;0
0.5 - cPQ>

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° . . ..
6> ",,'"...

j,d ,......

o.o;!'"
o

...

...
...

...

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

...

...

0.48

-

-

o 125MeV Bt
o 3.8GeV Ta"" 3.5GeV Xe. . 0.7GeV Kr
I

10

20

30

FLUENCE ( 1011 ions / cm2)
Fig. 1. The value of (j.p/ po plotted as a function of fluence for irradiations with 125 MeV Br and 3.8 GeV
Ta. These two irradiations have the same dJ / dx value,
0.84 ± 0.01 (arbitrary units) . The data for irradiations
with 3.5 GeV Xe and 0.7 GeV Kr are also plotted.
These two irradiations have the same dJ / dx value, 0.48
(arbitrary units).

Se, for describing the defect production process. This
result is consistent with the results of a previous studyof lattice parameter change in ion-irradiated EBCO. 6)
These results suggest that the atomic displacements
are triggered by Coulomb repulsion between primarily
ionized atoms.

References
1) N. Ishikawa et al.: Mat. Res. Soc. Symp. Proc. 504, 171(1998) .
2) N. Ishikawa et al.: RIKEN Accel. Prog. Rep. 32 , 99
(1999).
3) N. Ishikawa et al. : Phys. Scr. T 80, 559. (1999).
4) H. A. Bethe: Ann. Phys. 5, 325 (1930).
5) R. L. Fleischer et al.: Phys. Rev. 156, 353 (1967).
6) N. Ishikawa et al.: Nucl. Instrum. Methods Phys. Res.
B 135, 184 (1998).

Faculty of Engineering, Iwate University

87

RIKEN Accel. Prog~ . Rep . 33 (2000)

Effects of Defect Morphology on the Vortex Dynamics in
Bi2Sr2CaCu208+~ Irradiated with GeV Heavy Ions
N. Kuroda, N. Ishikawa, S. Okayasu, A. Iwase, H. Ikeda, R. Yoshizaki,* and T. Kambara
Previous experiments on swift heavy-ion irradiationof high-Tc superconductors show that the morphology of defects depends strongly on electronic stopping
power Se. 1 ) When Se is less than about 2 keY/A, elliptical defects are formed at intervals along an ion
path, whereas, when Se greater than about 2 keY / A,a continuous columnar defect (CD) is formed. We havestudied the effects of defect morphology on the vortex
dynamics in a Bi2Sr2CaCu208+8 (Bi-2212) high-Tc supercond uctor.
Bi-2212 single crystals (Tc ~ 90 K) were irradiatedwith the heavy ions 0.7 GeV 84Kr, 3.5 GeV 136Xe,
3.8 GeV 181Ta, and 3.1 GeV 209Bi, at the RIKEN Ring
Cyclotron. In order to characterize the morphology ofirradiation-induced defects, transmission electron microscopy (TEM) observations were carried out parallelto the ion path · which was also parallel to the c-axisof the samples. The TEM micrographs were taken at
the Foundation for Promotion of Material Science andTechnology of Japan (MST). Figure 1 shows the statistical distribution of the radii of defects in the ab-planefor 0.7 GeV 84Kr (Se ~ 1.4 keY / A), 3.5 GeV 136Xe(Se ~ 1.7 keY / A), 3.8 GeV 181Ta (Se ~ 3.1 keY / A),and 3.1 GeV 209Bi (Se ~ 4.1 keY / A). The defect radius increases with increasing Se of the irradiating ion.
For Kr irradiation with the smallest Se, the radii ofdefects in an ab-plane are more widely distribute thanfor Bi irradiation with the largest Se. This shows thatthe defect radius strongly fluctuates along the ion pathfor Kr irradiation.
The vortex dynamics was investigated from theac susceptibility. We obtained the relation between
the frequency f and the loss-peak temperature T p ,at which the imaginary part of the ac susceptibility
showed a maximum. The ac susceptibility was measured under the ac field of 0.5 Oe and the dc field of
0.3 T. Both magnetic fields were applied along the caxis of the sample and were much lower than the doseequivalent field Bcp of 0.8 T (fluence = 4 x 10 10 /cm 2).
As is excepted for a glass transition, the power law behavior f rv (Tp - Tg)n can be observed, where Tg is
the glass temperature. The exponent n is 3.2 ± 0.3(Tg = 67.0 ± 0.4 K) for Xe irradiation, 3.9 ± 0.4(Tg = 67.5 ± 0.4 K) for Ta irradiation, and 4.3 ± 0.3(Tg = 68.7 ±0.3 K) for Bi irradiation, showing a univer-

Cryogenics Center, University of Tsukuba

88

0.21
0.1
0.0
0.2
o. 1

f

o 0.0

3

4

5

6

7

R (nm)
Fig. 1. Distribution of the radii of irradiation-induced defects for (a) 0.7 GeV 84Kr, (b) 3.5 GeV 136Xe, (c)3.8 GeV 181Ta, and (d) 3.1 GeV 209Bi . The lines show
the Gaussian fits.

sal power law of the Bose-glass transition which resultsfrom the production of CDs. For the Bose-glass transition, the value of the exponent n is expected to be
3.5-4.5. 2 ) For Kr irradiation with low stopping power,
however, a much larger exponent than for other irradiations, n = 9.6 ± 1.9 (Tg = 60.2 ± 1.8 K), was obtained.
In the Kr irradiation with Se ~ 1.4 keY / A, complete
CDs are not produced, thus the vortex dynamics isdifferent from that in Xe, Ta, and Bi irradiations.
References
1) Y. Zhu, Z. X. Cai, R . C. Budhani, M. Suenaga, and D.
O. Welch: Phys. Rev. B 48, 6436 (1993).
2) M. Wallin and S. M. Girvin: Phys. Rev. B 47, 14642(1993).

RIKEN Accel. Prog. Rep. 33 (2000)

Radiation Annealing Induced by Electronic Excitation in Iron t
Y. Chimi, A. Iwase, N. Ishikawa, N. Kuroda, and T. Kambara
The interactions between energetic particles and aniron target have been studied. Polycrystalline iron thinfilms ",200 nm thick were irradiated at a low temperature (",77 K) with 0.5-2.0 MeV ions using a 2 MV Van
de Graaff accelerator,l) with 84-200 MeV heavy ionsusing a 20 MV tandem accelerator,2) both at JAERITokai (Japan Atomic Energy Research Institute, Tokai
Establishment) and with 3.1-3.8 GeV heavy ions using the RIKEN Ring Cyclotron. Defect accumulation
behavior during irradiation was observed by measuring
the increment in electrical resistivity of the specimen as
a function of ion fluence. The defect annihilation crosssection, a r , for each irradiation was derived from thedefect accumulation behavior. In the present report,
we mention the effects of electronic excitation in iron,focussing on radiation annealing, i.e., annihilation of
defects during irradiation.
Compared with ",1 MeV ion irradiation, we haveobserved strong radiation annealing for '" 100 MeV
and GeV heavy-ion irradiations.
In these cases,
the elastic collision not only is not dominant for
defect annihilation, but is negligible. We plotted a r
for '" 100 MeV and GeV ion irradiations in Fig. 1
against the electronic stopping power, Se, which isthe energy transferred through electronic excitation
per unit length along the ion path. The value ofa r is nonlinearly correlated with Se (a r '" S;- 3).
However, ar's for some ions are different even at thesame Se. This result shows what is called the velocity
effect. The slower ions are more efficient for defectannihilation. The velocity effect indicates that Se is
not the most appropriate parameter for describing
this phenomenon. The excited state of secondary
electrons and the energy spectrum of excited electrons
are different for different ion velocities even at thesame Se. A similar ion velocity effect on damage
creation has also been observed in bismuth. 3 ) It is
insisted that the experimental track radii agree withthe theoretical ones estimated in the framework of
the thermal spike mechanism. 4) It is noted that inan oxide superconductor a primary ionization rate,
dJ / dx, is the dominant parameter for describing
atomic displacements. 5 ,6) The value of dJ / dx indicates the number of atoms ionized by an incident ion
per unit length along the ion path. Therefore, theresult of irradiation experiments in the oxide superconductor implies that defect production, especiallytrack formation, can be explained by the ion explosion
mechanism proposed by Fleischer et al. 7 ) In the case10-11~--~~~~~~I~--~~~~~r:• ~ 1OOMeV Ion Irradiations• GeV Ion Irradiations

10-12~,...-.,

10-13

/

e/

//

b

S
()
01-<

I • • -:

Sc

//

/

L.-...J

10-

14

15

10-

•

/
S 3/

(".l

Au

Cl

p

1=

•

•

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•

Ni.

Ta

• • Xe

B'1

-:

•

-;
/

""

E"-

",

C

•

10-16
10°

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...,

e

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102

Fig. 1. Defect annihilation cross section, (Yr, for ",,100 MeV
and Ge V ion irradiations plotted against the electronic
stopping power, Be.

of iron, we also have to find a pertinent parameter,other than Se, for describing this phenomenon. For
defect production in iron irradiated with GeV heavyions, Dunlop et al. suggest the parameter TJ = Zivo/v ,where Zi is the ion effective charge, Vo the Bohr velocity and v the ion velocity.8) They claimed that the
Coulomb explosion causes defect production in iron.
However, it remains uncertain whether or not the parameters dJ / dx and TJ can be applied to the radiation
annealing process.
References
1) Y. Chimi et al.: J. Nucl. Mater. 271/272, 236 (1999).
2) Y. Chimi et al.: Mat. Res. Soc. Symp. Proc. 504, 221(1998).
3) Z. G. Wang et al.: Nucl. lnstrum. Methods Phys. Res.
B 107, 175 (1996).
4) Z. G. Wang et al.: J. Phys.: Condens. Matter 6, 6733
(1994); J. Phys.: Condens. Matter 7, 2525 (1995).
5) N. Ishikawa et al.: Nucl. Instrum. Methods Phys. Res.
B 135, 184 (1998).
6) A. Iwase et al.: Nucl. lnstrum. Methods Phys. Res. B
146, 557 (1998).
7) R. L. Fleischer et al.: Phys. Rev. 156,353 (1967).
8) A. Dunlop et al.: Nucl. lnstrum. Methods Phys. Res. B
90, 330 (1994).

Condensed from the article in Nucl. Instrum. Methods Phys.
Res. B (2000), in press

89

RIKEN Accel. Prog. Rep. 33 (2000)

Infrared Spectroscopy Study on Vacancy-Oxygen Pairs In
CZ-Si Irradiated by 3.5 GeV Xe Ions
X. Diao, Y. Yoshida, K. Hayakawa,* F. Shimura,* T. Kambara, A. Iwase , and Y. Yano
Irradiation effects have been extensively studied for
decades, especially for electrons, neutrons and lowenergy ions. 1- 3 ) Defects are always produced and electronic properties are modified by irradiations or deliberate implantations. However, little is known so far
about the irradiation effects of high-energy GeV heavy
ions in Si.
In the present investigation, Czochralski-grown (CZ)
silicon was chosen as a target because it contains arather high concentration of oxygen, i.e., around 10 18
atoms/cm 3 , and therefore, the oxygen atoms can act
as sensitive probes to detect defects in infrared spectroscopy of Si. In addition, a conventional micro-FTIR spectrometer would make it possible to observe thedefect distribution directly along the ion tracks with aresolution of 20 /.Lm , since the ion range reaches up to
several hundreds of mm in Ge V ion irradiation.
Both CZ-Si and floating zone (FZ)-Si samples were
irradiated with 3.5 GeV Xe ions at total doses of
1.0 x 10 13 Xe/cm 2 and 1.0 x 10 12 Xe/cm 2 . The irradiations were performed from the (100) direction of
the Si crystal at room temperature. After the irradiation, the sample irradiated with the higher Xe dose
was prepared for micro-FT-IR measurements. All IR
spectra were measured at room temperature.
The infrared spectra of both nonirradiated and irradiated CZ-Si are shown for the different Xe doses
in Fig. 1. After irradiation, clear bands were found at
830 and 1107 cm- 1 , which can be assigned to vacancyoxygen (VO) pairs and interstitial oxygen , respectively.
The VO pairs were first observed in electron-irradiated
CZ-Si.l) In FZ-Si, on the other hand, we did not findthese oxygen bands. By comparing the interstitialoxygen concentration before and after the irradiation ,the production rate of VO pairs was determined to be'f7 = 2.9 X 10 2 pairs/ion.
The depth dependence of the infrared spectra in theion incident direction was obtained using a micro-FTIR spectrometer with a 20 x 600 /.Lm aperture, andthe results are shown in Fig. 2. The 830 cm -1 bandis clearly detected in the depth range between 0 and
350 /.Lm. The intensity of the band varies dependingon the depth. In the shallow region near the surface,
the band shows a broad tail, possibly due to otherdefects, which may be produced by a primary reaction between Xe ions and the Si surface. In the region
deeper than 350 /.Lm , the band at 830 cm- 1 completely
disappears. This indicates that the ions did not penetrate beyond a depth of about 350 /.Lm, which is in good
Shizuoka Institute of Science and Technology

90'7

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(a)

()

E

(b)

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\ Non-irradiated1200 1100 1000 900 800

1 200 1100 1000 900 800

1Wavenumber (cm- )Fig.!. IR spectra of CZ-Si irradiated with 3.5 GeV Xe
at total doses of (a) 1.0 x 10 13 Xe/cm 2 , and (b) 1.0 x
1012 Xe/cm 2 .

3~
2 c:~

1-eo

0]

«

1200

1100

1000

900

800

1
Wavenumber (cm- )Fig. 2. Depth dependence of the IR spectra of CZ-Si irradiated at the dose of 1.0 x 1013 Xe/cm 2 .

agreement with the ion penetration range evaluated bythe "TRIM" calculation. Because the electronic stopping power dominates the slowing down process for the
GeV region , the nuclear collisions are thought to contribute to the energy loss only at the ends of the ion
tracks. Accordingly, the present results strongly suggest that the VO defect was created by the energy loss
due to electronic excitation prosesses.
References
1) J. W. Corbert, G. D. Watkins, R. M. Chrenko, and R.
S. McDonald: Phys. Rev. 121, 1015 (1961).
2) P. C. Newman and D. H. J. Totterdell: J. Phys. C: Solid
State Phys. 8, 3944 (1975).
3) H. J. W. Zandvliet, H. B. Elswijk, E. J. van Loenen, 1.
S. T. Tsong: Phys. Rev. B 46, 7581 (1992).

RIKEN Accel. Prog. Rep. 33 (2000)

Evaluation of SEB in Power MOSFETs Caused by Heavy Ions
S. Matsuda, S. Kuboyoma, T. Takahashi, T. Suzuki, T. Hirose, H. Ohira, Y. Nagai, and M. Kase
Semiconductor devices used for artificial satellites
and spacecrafts are affected by radiation in space.
It is well known that the incidence of high-energy
heavy ions into semiconductor devices causes fourkinds of anomalies: single-event upset (SEU), singleevent latchup (SEL), single-event burnout (SEB) andsingle-event gate rupture (SEGR). Among them, SEB
was identified as a possible catastrophic failure modefor power MOSFETs with a double-diffused MOS(DMOS) structure. To date, numerous tests on SEB of
power MOSFETs have been performed, and its mechanism is becoming clear. SEB is triggered when aheavy ion passes through a power MOSFET biased
in the OFF state. Transient currents generated by theheavy ion turn on a parasitic bipolar transistor (BJT)
inherent to the device structure. Due to a regenerative feedback mechanism, a second breakdown sets in,creating a short circuit between the source and drain
which destroys the device. 1) Therefore, it is necessar;
to increase SEB tolerance in power MOSFETs to enable space application. National Space Development
Agency of Japan (NASDA) has studied SEB in power
MOSFETs caused by heavy ions from the RIKEN Ring
Cyclotron. 2)
Previously, the 250V-class power MOSFET,
2SK3041, for space application was developed. Currentry, we are trying to improve SEB tolerance inWe have
power MOSFETs using new methods.
performed irradiation tests with a beam of Ni 25 + at
25 MeV /u (total energy of 1450 MeV) on several. types of samples and have studied the breakdown
voltage data associated with SEB. Because the Ni-ion
beam passes through the atmosphere, the energy of
the ion at the sample was degraded to approximately
286 MeV. Therefore, the linear energy transfer(LET) of the ions at the sample surface (Si) was
about 26.7 MeV /(mg/cm 2) and the range was about
44.7/-L m .
First, we study the effect of the diffused selfalignment (DSA) process on SEB tolerance. Generally the DSA process has been used for commercial
devices. Usually, many different lithography processes
are needed to form IC patterns, but the DSA process
makes it possible to reduce the number of processes.
-- --- The advantage of the DSA process is to make the channellength short, thus it can be expected to improve theelectrical characteristics.
Four types of samples of 250V-class power MOSFETs were prepared. Three types of samples were fabricated using different DSA processes (DSA-l,2,3) andone sample was the reference sample (non-DSA process). We performed irradiation tests for these sam-

> 250
L..J

225

'-

> 200

'-

if)

0

175
-c
Q)
150

f-

0

(/)

It'-

lo....

-c

ICO

125

(/)

100

w

•

•
•

::Q

I

2SK3041

1

DSA-l

DSA-3

DSA-2

Fig. 1. DSA dependence on SEB threshold.

pIes. Figure 1 shows the test results of the DSA process effect on the SEB threshold. In Fig. 1, the SEB
threshold of the DSA sample is higher than that of
the reference sample (non-DSA process). It is clearthat the DSA process is effective in improving SEB
tolerance. Among the three DSA processes, the DSA2 process is the most effective, however, its mechanism
is not yet clear.
Second, we study the effect of the lifetime of carriers in power MOSFETs on SEB tolerance. It is known
that the voltage drop generated by the current along
the body layer cause the activation of the parasitic
BJT as a trigger of SEB.2) Thus it can be expectedthat SEB tolerance increases as the number of holes
injected into parasitic BJT (decreasing the lifetime ofcarriers) decreases. To control the lifetime of the carriers, we performed electron irradiation for power MOSFET, called "Lifetime Control" (LTC). The lifetime ofcarriers is governed by the electron dose and the annealing conditions.
Many LTC samples were prepared. These samples
were based on 2SK3041 (250V-class power MOSFET)
which NASDA had developed previously. To evaluate
the lifetime of the carriers, the reverse recovery time,...., 350
~

•

• ••
••

rJ)

~ 300

f-

"'0

0

~

~ 250
lo....

.s:.

+-'

CD
W

rJ)

1

200
100

200

·1
300

1

400

••
• •
500

600

Reverce Recovery Time Trr ens]
Fig. 2. Trr dependence on SEE threshold.

91

(t rr ) of these samples was measured. A short trr meansa short lifetime of carriers. It is expected that the SEB
tolerance increases as trr decreases. Irradiation test
results are shown in Fig. 2.
In Fig. 2, the SEB threshold VDS does not depend
on t rr , contrary to our expectation. The reason is
not yet clear, but it is apparent that LTC has no effect on SEB tolerance. We expect that such test results

92

will be applicable to improve SEB tolerance in power
MOSFETs.
References
1) M. Allenspach et al.: IEEE Trans. Nucl. Sci. NS-43,
2927 (1996) .
2) S. Kuboyama et al.: IEEE Trans. Nuc. Sci. NS-39,
1698 (1992).

RIKEN Accel. Prog. Rep. 33 (2000)

Dynamic Behavior of a Nuclear Probe 57Mn/57Fe in Si after
Projectile-fragment Separation and Implantation
Y. Yoshida, Y. Kobayashi, X. Diao, K. Hayakawa,* K. Yukihira,* F. Shimura,* A. Yoshida,
Y. Watanabe, F. Ambe, and Y. Yano
An on-line isotope separator after projectile nuclear
fragmentation (RIPS) can be applied to produce aradioactive isotope for 57Fe Mossbauer spectroscopy,that is, 57Mn decaying to 57Fe with a half-life of
1.45 min. The highly energetic particles with several
GeV from the separator can be implanted even in thedepth range of several hundreds pm from the surface,providing atomistic information on both the local surroundings and the dynamics of the pro be atoms at the
final lattice sites through hyperfine interactions. It istherefore appealing that this method opens a new possibility for nanometer-scale materials science particularly in bulk materials, which would be complementary
to high-resolution electron microscopy for thin samples, or scanning probe microscopy for surface.
The 57Mn beam was separated using RIPS after
the projectile fragmentation of 59Co nuclei with a
Be target with a thickness of 185 mg/cm 2 . Theenergy and intensity of the primary 59Co beam
were 80 MeV/nucleon and approximately 300 enA(I"V 12 pnA), respectively. In order to stop all the 57Mn
nuclei in the sample, the beam energy had to be suppressed by using a 470-pm-thick Al plate as a degrader. Finally, the implantation energy was several
MeV /nucleon, leading to the implantation depth of
100 ± 10 pm. The intensity of the 57Mn secondary
beam was typically 2 x 105 particles / s.
In order to investigate the dynamical behavior of
57Fe atoms in the Si matrix, we used two different
floating-zone (FZ) Si wafers for two different experimental periods ; a (100) oriented Si wafer and a (111)oriented Si wafer with thicknesses of 530 pm and525 pm, respectively. These samples enabled us tomeasure Mossbauer spectra from different orientations.
The resistivities of the samples were 100 and 10 ncm,
respectively, corresponding to boron concentrations of2 x 10 16 and 2 x 10 15 /cm 3 . The 14.4-keV ,),-rays
from 57Fe/ 57 Mn were monitored by a CdZnTe detector. Mossbauer spectra were measured by a parallelplate avalanche counter with a stainless-steel absorberwhich was 95% enriched by 57Fe. This counter w~
mounted on the velocity transducer. The measuring
time and the total implantation dose of 57Mn necessary for one spectrum were approximately 10 hours
and 10 10 57Mn, respectively.
Figure 1 shows the Mossbauer spectra of 57Mn/57Fe
in FZ-(111) oriented Si, which were measured between
350 and 650 K. The spectrum at 350 K can be fitted'·r~~~
r. ·. ...
...' '.. . .,~
100

110
105

550 K

(

2 100 ~..
c

5

U 110
105
"(J

OJ

~

N

ro 110

§

105

Z

100

475 K

••
-~-

100

~~
..:-:."""""'~.!-...t..t....!.,;,I

f

425K

••••

110

,. [ .....A.~.....
'00

~

·2

3iOK
;.

]

~

.,

Velocily (mmfs)
Fig. 1. 57Fe Mossbauer spectra in FZ-Si following projectile
fragmentation and implantation of 57Mn.

by two components corresponding to interstitial Fe on
the left-hand side (8 = -0.76(2) mm/s) and substitutional Fe on the right-hand side (8 = 0.02(5) mm/s) ,which are in good agreement with those obtained at
300 K in the first experiment on FZ-(100)Si.1) As thetemperature is elevated, the area intensity of the interstitial line decreases, while the substitutional line
increases and is accompanied by broadening in bothlines. In addition, the interstitial fraction decreases
above 500 K.
In order to interpret the dynamical behavior observed in the present study, we must consider two characteristic times, namely 100 sand 100 ns due to thelifetime of 57Mn and 57Fe, respectively. It is expectedfrom the tracer diffusivity of Fe in Si that the jump
frequency of interstitial Fe atoms reaches 2 x 103 and2 x 106 at around 400 K and 600 K, respectively. This
would lead to a kinetic reaction, on one hand, between
Fe interstitals and vacancies produced by the slowingdown process of 57Mn, and on the other hand, diffusional line broadening accompanied by a relaxation
effect on the isomer shift. Details will be discussed
elsewhere.
References
1) Y. Kobayashi et al.: RIKEN Accel. Prog. Rep. 33, 109

Shizuoka Institute of Science and Technology(2000).
93

RIKEN Accel. Prog. Rep. 33 (2000)

Atomic-Foree-Microscopy Observations of FZ-Si after GeV- 57 Mn
Implantation Using RIKEN Projectile Fragment Separator (RIPS)
X. Diao, Y. Yoshida, Y. Kobayashi, A. Yoshida, Y. Yano, K. Hayakawa,* and F. Shimura*
It is known that ion tracks can be introduced in thewake of high-energy ions passing through solid materials, and to date they have been found in mica, graphite,some metal alloys and most insulators. 1 ,2) However in
Si, noone has observed the ion tracks after monoatomic
GeV-heavy-ion irradiation. In the present investigation, atomic force microscopy (AFM) is used to search
for ion tracks in a cleaved Si surface.
Two floating-zone (FZ) Si (100) samples were obtained after in-beam Mossbauer-spectroscopic experiments, which achieved the implantation of 3.2-GeV57Mn into FZ-Si using an on-line isotope separatorof projectile fragments (RIPS) and simultaneously,
Mossbauer measurements were made of 57Fe decayedfrom 57Mn. The results are also presented in thisreport. 3 ) The first sample was obtained from lowtemperature measurements at 30, 100, 150, 250 and
300 K, and the second sample from high-temperature
measurements at 300, 500, 600 and 700 K. The total
implantation dose of 57Mn ions for both samples wasaround 5.0 x 10 10 Mn/cm2. In order to observe the ion
tracks, the implanted sample was cleaved in the (110)plane and was immediately placed in the AFM vacuum
chamber. Pumping to 1.0 x 10- 6 mbar requires around
15 minutes.
Typical AFM micrographs of the first sample areshown in Fig. 1. The implantation was performed
from the (110) direction of the Si crystal, i.e., incident at 45° to the (100) Si surface. The present
geometry enables us to observe the region from thesurface to the ion range, which is also illustrated inFig. 1. Two types of swellings are clearly observed on
the cleaved surface with diameters of approximately
100 Jlm and 20 nm. The larger mountainlike bumps are
distributed among the smaller bumps with mono disper sed sizes. The number of smaller bumps is approximately 1.5 x 10 10 cm- 2, which is close to the total implantation dose. The swellings disappear around theion range with a sharp boundary. Figure 2 shows an
AFM micrograph observed in the second sample. Only
pin-shape bumps can be seen with a diameter of approximately 30 nm, but the number of the bumps isabout 1.5 x 109 cm- 2, one order of magnitude lower
than the total implantation dose. This suggests thatthe swellings are annihilated considerably at high temperatures.
The swellings observed in the present investigation
are believed to be related to the ion tracks. However,the formation mechanism of the swellings from the ion
Shizuoka Institute of Science and Technology

94

AFM image ofMn irradiatedFz-Si(100).

Total dose:
5.0X 10 10
Mn/ cm2

Fig. 1. AFM micrographs of cleaved FZ-Si implanted with
57Mnj57Fe at low temperatures from 30 K to 300 K.

Fig. 2. AFM micrograph of cleaved FZ-Si implanted with
57Mnj57Fe at high temperatures from 300 K to 700 K.

tracks is still not clear after the samples were cleaved,
and further experiments are necessary.
References
1) F. Thibaudau, J. Cousty, E. Balanzat, and S. Bouffard:
Phys. Rev. Lett. 67, 1582 (1991).
2) G. Szenes: Phys. Rev. B 51, 8026 (1995).
3) Y . Yoshida et al.: RIKEN Accel. Prog. Rep. 33, 93(2000) .

RIKEN Accel. Prog. Rep . 33 (2000)

A New Spin Polarimeter Proposed for
Spin-Polarized Slow Positron Beams
Y. Nagai,· J. Kim , Y. Nagashima, Y. Itoh, and T. Hyodo
A new spin polarimeter for the spin-polarized slow
positron beam l ) is proposed. The Doppler broadening method with an a-Si0 2 sample is utilized. The
polarization is determined from the magnetic field dependence of the S-parameter, i.e. , the ratio of counts
in the central portion of the annihilation photopeak of
the Doppler broadening spectra to the total counts inthe peak.
The S-parameter is related to the fraction of thepositronium (Ps) which self-annihilates into 21' Ips as
S = cdps + /3, where Q and /3 are constants. Ips isrepresented by
I_ K,I'p
Ps -

y2

K,I'p

1

p
-r -+1
2 Fo ' + -r -1-yp'
+ y2 F "(1)0'

where F o' and F p ' are the fractions of the perturbed
ortho-Ps and the perturbed para-Ps formed in a magnetic field B;
1

Fo' = 8(1 + y2) [(1 + y)2(1 - P) + (1 - y)2(1 + P)]
(2)
and
1
F p' = 8(1 + y2) [(1 - y)2(1 - P) + (1 + y)2(1 + P)].

(3)

y is given by y = x/[(1 + x 2 )l/2 + 1] with x =4J.LB / K,hwo, and P is the positron spin polarization
along B at the instant of the Ps formation. J.L is themagnetic moment of the electron and hwo is the hyperfine structure splitting between the ortho-Ps and thepara-Ps in vacuum. K, is the electron-positron contact
density of Ps in the sample relative to that in vacuum.
r 0' and r p' are the annihilation rates of the perturbed
ortho-Ps and the perturbed para-Ps in the sample andare given as follows

r

0'

= K,

1'0 + y21'p
1 + y2 + I'pi ckoff

(4)

and

r p' --

2

y 1'0 + I'p
K,
1 + y2 + I'pickoff·(5)

1'0 and I'p are the self-annihilation rates of ortho-Ps

and para-Ps in vacuum, respectively, and I'pickof f is
the Ps pickoff annihilation rate in the sample. Figure 1 shows the dependence of Ips on B. The asymmetry around B = 0 is ascribed to the positron spin

P=O.3 "Y pickoff=O

0.5/----~-----------,\ i ,/ P=O.3 "Y piCkou=O.63ns-

1_P=: 'Y PiC\U=O.63ns \.

0.3
0.2

. . . . . . .~

! ;'

\1,'

,"
'J.,' ~ :/'- . ___ L--'
.

_.-,

--

P=O.3 "Y plckou=2ns~

1Magnetic flux density (T)Fig. 1. Theoretical values of Ips for samples with K = 1 asfunctions of the magnetic flux density.

polarization along the magnetic field. The polarization
can be determined if the magnetic field dependence of
Ips or S-parameter is measured for materials with asuitable pickoff rate. One of the best materials for thispurpose is a-Si0 2, not only because the pickoff rate issuitable but also because the Ps formation efficiency isvery high (",,80%).
The polarization of the spin-polarized slow positron
beam has so far only been measured using the lifetime
method using a channel electron multiplier array.2,3)
The data analysis of the lifetime spectra is complicatedbecause Ps thermalizes slowly. The method proposed
here provides a much simpler way to measure the polarization of the beam.
In order to examine the sensitivity of this method,
we have measured the polarization of the positrons
from 22N a. 4) An 22N a source of 8 J.LCi was deposited 'between two identical Kapton foils of 7.5 J.Lm thickness. The source was held between an a-Si0 2 sample and a stack of 15 Kapton foils of 0.125 mm thickness. Positronium is not formed in Kapton. Magnetic
fields up to 20 kG were applied using an electromagnet. I'pi ckof f was determined using the conventional
positron lifetime method. The optimized value of polarization is 0.327 ± 0.015.
If we assume that the reflection of positrons from astack of Kapton foils and the absorption of positrons in
the Kapton foil holding the source are negligible, thetheoretical value of the polarization is O.5(v/c), where(v / c) = 0.67 is the longitudinal polarization averaged
over the (3+ spectrum of 22Na. The polarization determined above is consistent with this value within theInstitute of Materials Reserch, Tohoku University

95

range of statistical error.
References
1) J. Kim et al.: RIKEN Accel. Prog. Rep. 33, 216 (2000).

962) A. Rich et al.: Appl. Phys. A 43, 275 (1987).
3) T. Kumita et al.: Appl. Surf. Sci. 116, 1 (1997).
4) Y. Nagai et al.: submitted to Nucl. Instrum. Methods
Phys. Res. B.

RIKEN Accel. Prog. Rep. 33 (2000)

Xe Bubble Formation in Xe-Implanted Fe as Observedby the Channelling Method t
E. Yagi, T. Sasahara,*1 T. Joh,*2 M. Hacke,*3 T. Urai, T. Sasamoto,
N. Tajima, T. Watanabe, and S. T. Nakagawa*2

It has been demonstrated that heavier inert gas
atoms (Ar, Kr and Xe) implanted into metals at room
temperature precipitate into a solid phase at high implantation doses. 1-3) These are often referred to as
solid inert gas bubbles or solid inert gas inclusions. In
fcc metals, they have an fcc structure which is crystallographically well aligned with the matrices. Although
the growth of such bubbles has been extensively studied by transmission electron microscopy (TEM), there
have been only a few studies on their nucleation andformation processes. For studies such as that of thenucleation of bubbles in the initial stage of implantation, which is unobservable by conventional TEM, thechannelling method is very useful because it gives information on the lattice locations of implanted atoms.
In previous channelling studies on Kr-implanted Al(fcc), the nucleation of Kr bubbles and their solidification processes have been extensively studied. 4- 9 ) In
the present study, to observe the difference in the stateof heavier inert gas atoms in the initial stage of implantation between fcc and bee metals, channelling experiments are performed on Xe-implanted a-Fe (bee) andthe initial stage of Xe bubble formation is discussed.
Xe+ ions were implanted into Fe single crystals
at room temperature at an energy of 150 keV atfour different doses 10 14 , 4 X 10 14 , 10 15 and 10 16 Xeions / em 2. Channelling angular scans were performedat room temperature for (100), (110), (111) and {100}channels by means of the Rutherford-backscattering
method with a 1.5 MeV He+ beam provided by a tandem accelerator.
The channelling angular profiles of the yields of He
ions backscattered by Fe atoms (the Fe angular profile) and those by Xe atoms (the Xe angular profile)for the 10 14 and 4 x 10 14 Xe ions/cm 2-implanted specimens are shown in Fig. 1. In the 10 14 Xe ions/cm 2implanted specimen, the Xe angular profile exhibitsa shallow dip, which has a fine structure, with a relative depth of about 50% of that of the Fe angularprofile (the Fe dip) and with approximately the sameangular half-width as that of the Fe dip for all thechannels investigated. On the Xe dip, a small central
peak is superimposed for the (100) and (110) channels and small double peaks around ±0.15° for the

*1
*2

*3

Condensed from the article in J. Phys. Soc. Jpn. 68, 4037
(1999)
Department of Physics, Chuo University
Department of Applied Physics, Okayama University of Science
Institut fUr Schicht- und Ionen-technik, Forschungszentrum
Jtilich GmbH, Germany(111) channel. In the 4 x 10 14 Xe ions/cm 2-implanted
specimen, the Xe dips become shallower. On the Xe
dip, small off-centre peaks are superimposed around±0.2° for the (100) channel and a small narrow dip
for the (111) channel. For the (110) channel a finestructure is not clearly observed. With increasing
implantation dose, the Xe dips become much shallower and the fine structures are no longer clearlyobserved.
These results suggest that the majority of the Xeatoms are distributed over substitutional (S) sites andrandom (R) sites. The remainder are located at thesites responsible for the fine structures, which are considered to be tetrahedral (T) interstitial sites in the
10 14 Xe ions/cm 2-implanted specimen and the (111)displaced (D) site, i.e., the site displaced from an S
site in the (111) direction in the 4 x 10 14 Xe ions/cm 2implanted specimen.
The lattice locations of the Xe atoms and their distribution were determined by comparing the observed
Xe angular profiles with those calculated taking into
account the four kinds of sites, i.e., the S, R, T and D
sites, for various distributions and various magnitudes
of displacement of the D site. For the 4 x 10 14 Xe
ions/cm 2-implanted specimen the Xe angular profiles
can be successfully reproduced by taking the magnitude of displacement of the D site to be 0.085 nm fromthe S site and for a distribution of Xe atoms of 40-43%
at S, 50-53% at Rand 5-10% at D sites. For the 10 14
Xe ions/cm 2-implanted specimen, they can be r,eproduced for the distribution of 47-50% at S, 35-38% at
R, 9-12% at T and 3-6% at D sites. With increasing implantation dose, the S-site occupancy decreases,
whereas the R-site occupancy increases. The changesof T- and D-site occupancies are more complex, but
generally tend to decrease with increasing dose.
The S, D, T and R site occupancies are ascribed
to isolated Xe atoms at S sites, Xe atoms associatedwith one vacancy (XeV) at one of their nearest neighbour sites as a result of a strong interaction between
Xe atoms and the vacancies (V) introduced during Xe
implantation, Xe atoms associated with four vacancies(XeV4 ) and Xe atoms associated with a much larger
number of vacancies, respectively.
From the above discussion, it is concluded that at
the initial stage of Xe implantation in Fe, Xe-vacancy
complexes, i.e., XeV, XeV4 and Xe atoms associatedwith a larger number of vacancies are formed, and they
act as nucleation centres for the subsequent growth of
Xe inclusions (bubbles). For the sake of comparison,

97

o
(a)

T
(lOO>

o

~~
o

T
(110)

T

<111>

o

T

noo} oFe
eXe

1.0:g 0.5
\l)

>-

"2

.!::!

0
(b)

"0

E

o 1.0

z

0.5

0L-~~-L~~~~L-~-L~~L-~~~2~L-~-L~~~~~~-L~~----~--~

Angle (deg)Fig. 1. Channelling angular profiles obtained at room temperature for (a) the 1014 and (b) 4 x 10 14 Xe
2ions/cm -implanted specimens. Solid curves and dotted curves have been drawn to guide the eye. In
the upper part, the projections of the 0 and T sites onto the plane perpendicular to the channel inquestion are shown by open squares with the relative weights. The open circles and lines represent
the projections of the atomic rows and planes, respectively.

it should be noted that in the case of Kr in Al (fcc)
also, the Kr-vacancy complexes, i.e., KrV4, KrV6 andKr atoms associated with a larger number of vacancies
act as nucleation centres. A more detailed description
is given in Ref. 10.
References
1) A vom Felde, J. Fink, Th. Muller-Heinzerling, J.
Pfluger, B. Scheerer, G. Linker, and D. Kaletta: Phys.
Rev. Lett. 53, 922 (1984).
2) C. Templier, C. Jaouen, J. P. Riviere, J. Delafond, andJ. Grilhe: C. R. Acad. ScL, Ser. 2 299, 613 (1984).
3) J. H. Evans and D. J. Mazey: J. Phys. F 15, L1 (1985) .
4) I. Hashimoto, H. Yorikawa, H. Mitsuya, H. Yamaguchi,
K. Takaishi, K. Kikuchi, K. Furuya, E. Yagi, and98

M. Iwaki: J. Nucl. Mater. 149, 69 (1987).
5) E . Yagi, M. Iwaki, K. Tanaka, I. Hashimoto, and H.
Yamaguchi: Nucl. Instrum. Methods Phys. Res. B 33,
724 (1988).
6) E. Yagi: Nucl. Instrum. Methods Phys. Res. B 39, 68(1988).
7) E. Yagi, I. Hashimoto, and H. Yamaguchi: J. Nucl.
Mater. 169, 158 (1989) .
8) M. Hacke and E. Yagi: J. Phys. Soc. Jpn. 64, 800(1995).
9) E. Yagi: Phys. Rev. Lett. 67, 3804 (1991).
10) E. Yagi, T. Sasahara, T. Joh , M. Hacke, T. Urai,
T. Sasamoto, N. Tajima, T. Watanabe, and S. T.
Nakagawa: J. Phys. Soc. Jpn. 68, 4037 (1999).

RIKEN Accel. Prog. Rep. 33 (2000)

Observation of Ion Current in Superftuid Helium
Q. Hui and Y. Matsuo

During the past two decades, laser spectroscopic
studies of impurities trapped in liquid helium have provided much insight into the quantum liquid. Although
the first experiment of this kind was performed with
Ba+ trapped in superfluid helium in 1986 by the Heidelberg group,l) later studies were carried out exclusively on neutral species. Recently, in our experimental
and theoretical studies on neutral Ag and light alkaline
earth atoms such as Be and Mg, we have found thata stronger attractive force between the excited stateof these atoms and helium atoms results in dynamics totally different than those of other atoms whichhave a weaker attraction to helium. Metal-helium exciplexes have been found to be formed when the Ag,
Be and Mg atoms were excited to a p-orbital. 2) Singly
changed alkaline earth ions have a strong attraction tohelium atoms and suitable transitions in UV and visible regions, and are very good candidates for studying
dynamics of the exciplex formation process. We are
currently preparing experiments with Ca + and Sr+ insuperfluid helium. In this paper we will report ourrecent progress.
The experimental setup is illustrated in Fig. 1. A
metal cryostat (Oxford) with quartz windows wasfilled with He II. A quartz cell was placed above theliquid and the cell itself was also filled with He II.
A metal sample was suspended about 1 cm above
the quartz cell. An ablation laser beam (532 nm,",20 mJ /pulse) was focused onto the sample throughone of the windows. Three electrodes were immersedin the liquid in such a way that the upper one remained
just 1-2 mm below the liquid surface. The upper
electrode (extractor) was typically at + 100 V andthe middle one at about +20 V. The third electrode(collector) was grounded through the impedance of adigital oscilloscope. The sample was at about +200 V.
The distance between the extractor and collector was
1- 2 cm. The positively charged ions produced via thelaser ablation were extracted into He II by the electricfield and the ion current was monitored on the digital

sample +200V
Hell----@'" ---:====t:1

Helltransfer
tube

+20V

excitation laser

PMT~

monochromator

oscilloscope

Fig. 1. Experimental setup.
oscilloscope. When the setup is complete, A CW laser
beam (under preparation) will be used to intersect theions below the extractor and excites the ions. The laser
induced fluorescence (LIF) emitted by the ions will be
detected at a right angle by a photomultiplier (PMT)through a monochromator.
We have observed the ion current produced by laser
ablation on a Sr sample. To increase sensitivity, theimpedance of the digital oscilloscope was set to 1 MO.
The pulsed current signal was composed of two parts.
Immediately after the laser pulse, a relatively sharp
peak appeared which was assigned to electrons. The
current signal corresponding to positively changed Sr+ions appeared about 1 J-lsec after the laser pulse andextended to about 1 msec. The intensity of the signal was found to depend sensitively on the laser power
and the surface condition of the sample. A rough estimation showed that about 106 to 108 Sr+ ions were
produced in the liquid by each laser pulse. An LIF
experiment using a CW laser and a photon-counting
method will be performed very soon.
References
1) H. J. Reyher et al.: Phys. Lett. 115, 238 (1986).
2) J. L. Persson et al.: Phys. Rev. Lett. 76, 1501 (1996) .

99

RIKEN Accel. Prog. Rep. 33 (2000)

Observation of a Full Dispersion Curve for the Low Energy
Excitation in a Spin Ladder
M. Matsuda, K. Katsumata, R. S. EccIeston,*1 S. Brehmer,*2 and H.-J. Mikeska*2
Low-dimensional antiferromagnets show novel phenomena originating from quantum fluctuations. The
spin ladder system is interesting as a system between
one- and two-dimensions. Extensive theoretical andexperimental studies have been performed on spin ladder systems. 1) La6CaSCu24041 consists of both chains
and two-leg ladders of copper ions. The structure of
the CU203 ladder is shown in Fig. 1. The CU203 ladder is a good example of an S = ~ Heisenberg two-leg
ladder.
Neutron scattering experiments were carried out
in single crystals of La6CaSCu24041 on the high energy transfer (HET) chopper spectrometer on the ISIS
pulsed neutron source at the Rutherford Appleton
Laboratory.
Figure 2 shows the experimental w-Q dispersion
relation for the two-leg spin ladder in La6CaSCu24041.
As is evident from this figure, we were successful inobserving a full dispersion curve from the spin-ladder.
As far as we are aware, this is the first experimental
observation of a full dispersion curve. The standard
analysis of experimental data for spin ladders uses
only the two parameters J 1eg and J rung , assuming thesimplest 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 (Le. 24 spins) and periodic
boundary conditions. We obtained the best fit toour data for Jrung = 65 me V and J 1eg = III me V
(Jleg / J rung = 1.7).
These values are not consistent(1) with the expectation from a geometrical consideration that the Cu-O-Cu exchange on legs andrungs should be approximately equal and (2) with theresults of an exact diagonalization calculation for thelleg

Jrung~L61 :
eu 0

!]

Fig. l. Structure of the CU203 ladder. Various interactions
between copper ions are also shown.

*1
*2

100

ISIS Facility, Rutherford Appleton Laboratory, UK
Institut fUr Theoretische Physik, Universitiit Hannover ,Germany

300

1S0meVEi _ _ J 1eg =111meV _____ J 1eg =112meV•o 300meVEis;- 250... SOOmeVEi
600meVEi

CD

J rung =65meVb.

E

J rung = 102me V
J ring =10.2meV':' 200

CDenc
as 150'->- 100

C)
'-

CD

c

w

50
0

0

2

a (A-1 )3

4

5

Fig. 2. w-Q dispersion relation for the two-leg spin ladder. The solid and dotted curves are the theoretical ones with Jleg = 111 me V and J rung = 65 me V
and with Jl eg = 112 meV , J rung = 102 meV, andJ ring = 10.2 meV, respectively. These theoretical curves%1f
are drawn through the points calculated for Q(n = 0, 1,' . ·, 6).

electronic state of cuprates performed by Mizuno etal., which gives Jleg/Jrung = 1.1. 2)
We then calculated the dispersion with an additional ring exchange J ring , which was recently proposed by Brehmer et al. 3 ) It was shown that the ringexchange reduces the gap energy at Q = 1f considerably, thereby requiring larger values for J rung andJ 1eg . The dotted curve in Fig. 2 is the theoreticalone with J rung = 102 meV, Jleg = 112 meV, andJ ring = 10.2 meV. These results suggest that a moderate amount of ring exchange around the basic ladderplaquettes (about 10% of the main Cu-O-Cu bilinear
exchange) should be included into the Hamiltonian of
the two leg ladder, which is quite consistent with recent
theoretical calculations. 4)
References
1) For a review, see E. Dagotto and T. M. Rice: Science
271, 618 (1996).
2) Y. Mizuno, T. Tohyama, and S. Maekawa: Phys. Rev.
B 58, R14713 (1998) .
3) S. Brehmer et al.: Phys. Rev. B 60, 329 (1999).
4) Y. Mizuno, T. Tohyama, and S. Maekawa: J. Low
Temp. Phys., in press.

RIKEN Accel. Prog. Rep. 33 (2000)

p,SR Study on the 1/8 Effect in the Bi-2212 System
I. Watanabe, M. Akoshima,* Y. Koike, and K. Nagamine

The "1.8 effect" 1-4) is now one of the most important problems in the study of the mechanism ofhigh-Tc superconductivity (SC). Recently, anomalous
suppression of the SC around the hole concentrationp = ~ per Cu was observed in a Zn-substituted Bi2212 system by Akoshima et al. 5 ) We carried out muon
spin relaxation (J.tSR) measurements of Zn-substituted
Bi2Sr2Ca1-x Yx(Cu1-yZnyh08+8 in order to examine
the existence of the ~ effect in the Bi-2212 system. 6 ,7)Samples of Bi2Sr2Ca1-x Yx(Cu1-yZnyh08+8 wereprepared by the conventional solid-state reaction
method. 5) J.tSR measurements were carried out at
the RIKEN-RAL Muon Facility in the UK. A spinpolarized pulsed surface muon beam with a momentumof 27 MeV Ic was used.
'
Figure 1 shows the temperature dependence ofthe zero-field (ZF) J.tSR time spectrum of the Znsubstituted sample with x = 0.3125 (p rv k per Cu)
and y = 0.025 in which the high-Tc SC is anomalously
suppressed. 5) The absence of the statically orderedstate of the Cu spins in the Bi-2212 system is contrary
to the case of the La-124 systems in which long-range
magnetically ordered states have been observed. 2- 4)
Figure 2 shows the x dependence, namely, p dependence of the depolarization rate of the Zn-substituted
samples at 0.30 and 1.8 K. Large depolarization rates
at x ::::: 0.5 are due to the appearance of a magnetically ordered state of the Cu spins in the underdoped

S 1.0

Bi2Sr2Ca l.xY x(Cu 1.7ny)20S+0
x=O.3125. y=O.025

(1)

§
;:>.
r:./)

--<
"0

0.5

(1)

N

.l""4

..CI:S.O.30K6. 1.8 K
019.2 Kx 287K

§
0

Z

a

0

Bi 2Sr2Ca l.xYiCu l·7ny)zOS+6

".-..

--;'
()

100

100

(l)
r:./)

~

::i.

.'..

(,)"3

~

:'~'"

'-"

~

.... Tc (y=O.025)

'-"
(1)
~

~

10

~

~
0

.l""4
~

~

N

0

e:"

~

0.1

(1)

y=O.025

e: 0.30 K

Q

~

50

1.0

.~

..-

,..-..

0.. ':,~/

E1
0
D~

0: 1.8 K

0.01 L-.l--L~.......L...--1-....l.-..L-.i.-....l---l----'---l 0

0.7

0.6

0.5

0.4

0.3

0.2

Y-Concentration

X

0.1

Fig. 2. x dependence of the zero-field muon spin depolarization rate of BbSr2Cal- xY x(Cul-yZnyh08+8 with
y = 0'.0'25 at 0'.30 and 1.8 K. Dotted lines show the x dependence of Tc with y = 0.025 determined by Akoshima
et at. from the transport measurements. S )region. The depolarization rate decreases rapidly withincreasing p and increases anomalously around p = ~per Cu. This result indicates that the Cu-spin fluctuations slow down around p = k per Cu. This relationship between the slowing-down behavior of the Cu
spins and the suppression of SC is analogous to thatof the ~ effect established in the La:-124 systems. 3 ,4)Therefore, in conjunction with the results of the transport measurements,5) we can conclude that the k effectis likely to exist in the Bi-2212 system as well. Thisconclusion supports the suggestion that the ,k, effect is
a common feature in the high-Tc SC oxides which havea CU02 plane.
References

5

10Time (f.1sec)
Fig.!. Temperature dependence of the zero-field J,LSR timesp~ctrum of BbSr 2Cal- xY x(Cul-yZnyh08+0 withx = 0'.3125 and y = 0'.0'25 where 'the high-Tc superconductivity is anomalously suppressed. s ,7)1) A. R. Moodenbaugh et al.: Phys. Rev. B 38, 4596
(1988); K. Kumagai et al.: J. Mag. Mag. Mater. 76/77,
60'1 (1988).
''
2) G. M. Luke et al.: Physica C 185/189, 1175 (1991).
3) I. Watanabe et al.: J. Phys. Soc. Jpn. 61, 3058 (1992).
4) I. Watanabe et al.: Hyperfine Interact. 86, 60'3 (1994).
5) M. Akoshima et al.: Phys. Rev. B 57, 7491 (1998).
6) I. Watanabe et al.: Physica B 259/261, 557 (1999).
7) I. Watanabe et al.: Phys. Rev., B 60', R9955 (1999).

Graduate Schoql of Engineering, Tohoku University

lOl

RIKEN Accel. Prog. Rep. 33 (2000)

N. Nishida, W. Higemoto, 1. Watanabe, R. Kadono, K. Nagamine,
T. Mochiku , K. Hirata,*1 R. Sugano,*2 and T. Onogi*2
The behavior of flux and vortex lines in hightemperature copper-oxide superconduvstors (HTSC 's)
have been intensively studied from both academic
points of view and the viewpoint of practical application purposes. In HTSC's, due to their short coherent length, the two-dimensional nature of their superconductivity and the high superconducting transition
temperature, thermal fluctuation effects are remarkable and Hc2 (T) cannot be well defined, unlike conventional type-II superconductors. In Bi2Sr2CaCu20x(Bi-2212), the Josephson coupling between superconducting CU02 layers is so weak that in magnetic fields
higher than 0.03- 0.05 T , the interlayer Josephson coupling is destroyed and a "pancake" vortex is formed ineach layer, as schematically illustrated in Fig. 1. The
pancake vortices attempt to find stable places in each
CU02 layer, interacting magnetically with each other.
As a result, the flux lines tend to bend in Bi-2212.
The Josephson plasma resonance experiments have revealed the degree of this bending of flux lines. 1) Below
20- 30 K, the pancake vortices are static and exhibit
a vortex glass state. At higher temperatures, the vortices become mobile and a vortex liquid state has been
proposed on the basis of transport and magnetization
measurements. This behavior has been studied by thetranseverse magnetic field J.l+ spin rotation methods(TF-J.l+SR) by Lee et al. 2 ) It is important and interesting to measure the characteristic time of flux line motion in the vortex liquid state. However, the TF-J.L+SR
method is not able to determine whether the origin oftransverse J.l+ spin depolarization is due to the static
inhomogeneity of internal magnetic fields or due to the
dynamic fluctuations. We have calculated the transverse component, Bab, of the internal magnetic fields
in Bi-2212 in the vortex state, as depicted in Fig. 1
in the magnetic fields of 0.03 T and 0.05 T applied
perpendicular to the c-plane at various temperaturesby computer simulation. The average Bab values havebeen calculated as 4 t'V 9 X 10- 4 T with increasing temperature from 4.2 K to 80 K. If this magnitude of Bab
exists and fluctuates dynamically, then the characteristic fluctuating time can be determined by the longitudinal magnetic field J.l+ spin relaxation method (LFJ.L+SR) from an exponential damping of the J.L-e decay
asymmetry. Thus, we performed LF-J.l+SR on single
crystals of underdoped Bi-2212 (Tc = 83 K) with highstatistics (t'V 108 events in each J.L+SR spectrum) at the
RIKEN-RAL Muon Facility. Figure 2 shows the time
evolution of the muon spin polarization under a LF of_--t-_~ Bc~ab t~+

(a)

~+

-+

(bl

Fig. 1. Pancake vortices are schematically depicted. Small
arrows indicate the initial muon spin direction for (a)LF-J.LSR and (b) TF-J.LSR.

0.1 2
0.1

I

I

0.08
0.06
0.04

~
G)
E

~

Bi 2Sr2CaCU20y
LF 200 G 100 K

0.02
0
0.1
0.08
0.06
0.04
0.02
o

LF 200 G 60 K~~~~~~~~~~~~o10Time(j.l.S8C)

15

20

Fig. 2. Time evolution of muon spin polarization under a
LF of 0.02 T at 100 K and 60 K.

0.02 T at 100 K (normal phase) and 60 K (superconducting phase and immediately above the vortex lattice melting temperature, Tm). The Tm is determinedto pe 55 K at 0.02 T by the magnetization measurement. We observed no significant differences between
the data. This implies that the timescale of the vortex
dynamics is beyond the time range of the LF- J.l + measurements, that is, the fluctuating time is either fastor static. A detailed analysis is now in progress.
References

*1
*2

102

NRIM
Advanced Research Laboratory, Hitachi Ltd.

1) S. 1. Lee et al.: Phys. Rev. Lett. 75,922 (1995).
2) Y. Matsuda et al.: Phys. Rev. Lett. 78, 1972 (1997).

RIKEN Accel. Prog. Rep. 33 (2000)

Current-Induced Vortex Motion in Type-II Superconductors
W. Higemoto, 1. Watanabe, K. Nagamine, S. Kuroda,* and K. Takita*
One of the central issues with regard to type-II superconductors is the structure and dynamics of theflux-line lattice (FLL). In the mixed state of type-II
superconductors, an external applied electric current
imposes the Lorentz force on flux lines, and the motionof the FLL is inhibited by the randomly distributed
pinning potential of material defects. Beyond a critical current density, FLL can become free of its pins
and flow. This process is complex and its microscopic
nature is not well understood. In particular, little is
known about the detailed structure and dynamics of
FLL as it becomes depinned and flows in response to
applied current. Theoretically, the moving glass stateis predicted under an external driving force. For example, Koshelev and Vinokur predict the existence ofa dynamic phase transition at a characteristic current
j = jt from the motion of the amorphous vortex configuration ("plastic flow" ) at j < jt to the motion of
the vortex crystal at j > jt ("elastic flow"). 1)
We report the muon spin rotation experiment on
high-quality single crystals of 2H-NbSe2. The j.L+SR
experiment was carried out at Port 2 of the RIKENRAL Muon Facility in the UK. Current flow was synchronized to the pulsed muon beam to prevent an excess Joule heating.
Under the current of 500 A/cm 2 , we did not observe
any significant effect of the current in j.LSR spectra forthe normal phase of 2H-NbSe2. Thus, we consider thatthe magnetic field induced by a current of 500 A/cm 2
is negligibly small for our measurements of 2H-NbSe2.
Figure 1 (a) and (b) show the j.LSR spectra under afield of 100 G of 2H-NbSe2 in the absence of current.
As shown in Fig. 1 (a) (normal phase) and (b) (superconducting phase), fast dumping of the muon spinrotation amplitude was observed only in the superconducting phase due to a field distribution in the vortex
state. We have fitted the data by the following simple
muon spin relaxation function:

P(t) = (Aexp( _(j2 t 2) + B) cos(wt + ¢).

(1)

The solid lines in Fig. 1 are fitting results. By fitting
the data, we obtained an asymmetry value of sample A
rv 0.013 and one of background B rv 0.010. In the superconducting phase, we found that the relaxation rate
under a current of 500 A/cm 2 , (jON = 0.78(5) j.LS- l ,did not differ from that without current, (jOFF =0.80(5) j.LS-l, within the error. This result indicatesthat the structures of FLL are nearly the same and theflow velocities of FLL are slower than 1 m/s. 2 ) Elastic
flows of FLL have been observed under a current

0.03
0.02
0.01
0
-0.01
-0.02

2H-NbSe 2

0.03

5.0K Current OFF(b) II J I
0.02

I I

~

+-'

(])

0.0 1

E
E
~

0

I

en

« -0.01
-0.02

0.03
0.02
0.01

0
-0.01
-0.02
-0.03
0

0.5

1

1.5

2

Time (Jlsec)
Fig. 1. j.tSR spectra of 2H-NbSe2 under a magnetic field of
100 G (a) at 10.0 K (normal phase) and I = 0, (b) at
5.0 K and I = 0, and (c) at 5.0 K and I "" 500 A/cm 2 .

greater than rv30 A/cm 2 in 2H-NbSe2 by Yaron et al. 3 )If we assume that our experiment is also in the elastic flow region and that the velocity of FLL is slow,
the structure of FLL under the current was not significantly different from that without current.
In conclusion, our result shows no significant difference in the structure and dynamic behavior of FLL
between the presence and absence of an external current in the time window of j.LSR in 2H-NbSe2.
References
1) A. E. Koshelev and V. M. Vinokur: Phys. Rev. Lett.
73, 3580 (1994).
2) W. Higemoto et al.: Physica B, in press.
3) U. Yaron et al.: Nature 376, 753 (1995).

Institute of Materials Science, University of Tsukuba

103

RIKEN Accel. Prog. Rep. 33 (2000)

p,SR Study on the Spin Dynamics of Kagome Antiferromagnet,
m-MPYNN·BF 4
1. Watanabe, N. Wada, K. Awaga,* S. Ohira, and K. Nagamine
The two-dimensional organic antiferromagnet, mMPYNN·BF 4 , has a radical with S = ~ on each unit
molecule which forms the Kagome lattice. I ) Two radicals form a dimer spin state with S = 1 through theintradimer ferromagnetic interaction 2Jo/ kB = 23.3 K
and two dimer spins couple through the interdimer antiferromagnet interaction 2Jo/k B = -3.1 K.2) Wada etal. suggested, based on a susceptibility measurement,that the dimer spin system showed a spin-gap statewith a nonmagnetic ground state. 3 ) We have carriedout j.lSR measurements at the RIKEN-RAL Muon Facility in the UK using an intense pulsed muon beamin order to investigate the magnetic properties of the
dimer spins.
Figure 1 shows the zero-field j.lSR time spectrum of
m-MPYNN·BF 4 obtained at 0.30,165 and 270 K. The
total number of muon events was 100 million. The recovery of the asymmetry parameter is clearly observedat around t = 8 j.lS at low temperatures. This indicates that the muon spin mainly depolarizes due torandomly distributed static internal fields.
The time spectrum was analyzed using the functione-),t x Gz(t, ~) . The first term represents the influence of the dynamically fluctuating dimer spin. The
second term is the static Kubo-Toyabe function which
represents the muon-spin depolarization due to nuclear
dipole fields. 4 )Figure 2 shows the temperature dependence of the
dynamic muon spin depolarization time,
The de-±.

m-MPYNNBF4 , ZF
00.30 K
0165 K6. 270 K

1.0

0.5

o

L-L-~~~~~-L-L~~~~~~~

o

5

10

15

Time (f.-isec)Fig.!. ZF-Il-SR time spectrum of m-MPYNN ·BF 4 at 0.30,
165 and 270 K. The total number of muon events was
100 million.
Graduate School of Arts and Sciences, University of Tokyo

104

~

u

7.0

Q)
C/'J

::i.

m-MPYNNBF4

'-'

6.3

.-

5.6

Q)

S

~

.-

aT

0
0

.-

4.9

,......;

4.2

~

~

N

~

0

0..

0

0

0000

Q)

Q

3.5

0.1

1

10

100

Temperature (K)Fig. 2. Temperature dependence of the dynamic muon spin
depolarization time which correlates with the dimer
spin fluctuations. The dimer spin fluctuations are constant below about 20 K (",dimerization temperature).

polarization time is constant below about 20 K where
two radicals form a dimer spin state, showing that the
dimer spin fluctuation frequency becomes also constant
below this dimerization temperature. The depolarization time exhibits an almost linear temperature dependence above 20 K .
After the dimer spin state is formed, quantum spin
fluctuation due to the intradimer ferromagnetic interaction between two radicals is expected.
Thisfluctuation frequency depends upon the exchange energy 2Jo, according to the wave function of quantum mechanics. Since the ferromagnetic exchange
energy is 2Jo/kB = 23.3 K,2) the quantum fluctuation overcomes the thermal fluctuation of the radical
spins below the dimerization temperature. When the
ferromagnetic quantum exchange fluctuation is dominat, the fluctuation frequency of the dimer spin is
ruled by this quantum fluctuation and is expected
to be independent of temperature. Therefore, theconstant fluctuation frequency observed below about
20 K indicates that the climer spin fluctuation is dominated by the intra-dimer ferromagnetic quantum fluctuation.
References
1)
2)
3)
4)

K. Awaga et al.: Chern. Phys. Lett. 195, 21 (1992).
N. Wada et al.: Phys. Rev. B 49,3975 (1993).
N. Wada et al.: J. Phys. Soc. Jpn. 66 , 961 (1997)
Y. J. Uemura et al.: Phys. Rev. B 31, 546 (1985).

RIKEN Accel. Prog. Rep. 33 (2000)

Radio-frequency Muon Spin Resonance of a Haldane-gap System
NiC 2 0 4 2 (2-·m ethylimidazole)eA. Fukaya, 1. Watanabe, S. Ohira, and K. Nagamine
Low-dimensional quantum spin systems with antiferromagnetic interactions, e.g., the Haldane-gap andspin ladder systems, have attracted much attention.
Since these systems possess a nonmagnetic singlet
ground state with an energy gap, it is expected thatmuon spin relaxation cannot be observed at low temperatures. In many compounds, however, an enhancement of muon spin relaxation was observed at low
temperatures. In order to clarify the origin of thisanomalous enhancement, it is important to examine
the spin susceptibility at the muon stopping site. If
implanted muons do not affect the magnetic property
of a sample, the spin susceptibility at the muon siteshould follow the bulk susceptibility. We have measured the muon spin resonance with a radio-frequency
field (RF-j.LSR) for a Haldane gap system NiC 2 0 4 2·(2methylimidazole) in which the anomalous enhancement of muon spin relaxation was observed at low
temperatures . 1)
We used the powder sample of NiC 2 0 4 2·(2methylimidazole). RF-j.LSR measurements were performed using a pulsed surface muon beam at the
RIKEN-RAL Muon Facility in the UK. We fixed thefrequency at 52.800 MHz and swept the longitudinal field (LF). The resonance amplitude is defined as
A on / A off, where A on ,off == (N~n,off _ N~n,off) / (N~n , off +N~n,off). N~n ,off and N~n ,off denote the integratedpositron-count rate in forward and backward directions, respectively, with the RF power on or off.
The LF dependence of the resonance amplitude(resonance curve) is shown in Fig. 1 (a).
As areference, the temperature dependence of the bulk
susceptibility, X, is shown in the inset. X includes
the Curie-Weiss term due to impurities; the bulk
susc.eptibility corrected by the Curie-Weiss term,
Xcorr , is shown by the solid curve. The width of theresonance curve increases and the amplitude decreases
with decreasing temperature. It is known that thepresence of longitudinal or transverse relaxation
increases the width and reduces the amplitude of
the resonance curve. The change of the width andamplitude at low temperatures suggests that thelongitudinal or transverse relaxation is enhancedwith decreasing temperature, which is consistent
with the previous results of muon spin relaxation
measurements. 1) We fitted the LF dependence ofthe resonance amplitude by a Lorentzian function.
The shift of the resonance field, K, obtained byfitting, is shown in Fig. 1 (b). K is negative. With decreasing temperature, K increases and shows a peak at(a).

1.0 --~--- ------- - - - ---------- --- -------- - - -- --

j:E;]

0.6

:
6
C

0.4

2

1

<-<

0.2

00

3840

3860

3880

3900

100
200
T(K)

3920

3

3940 3960

LF (G)
(b)

0.00

----

~ -0.02 ~

•
•

,

'-'"

~

+

002t=J,....... 0.00
!'§?

,.

.... _ ... -+- ---;;-0.02 __ - - - - •

-0.04
-0.04
0.0

X

1.0

2.0

3.0

(10-Semu/g)

COIT

-0.06
0

50

100

150

200

250

300 .

T (K)
Fig. 1. (a) Longitudinal field dependence of the resonanceamplitude. The inset shows bulk susceptibility, X. The
solid curve shows Xcorr . (b) Temperature dependenceof K. The inset shows K as a function of Xcorr.

around 50 K.
If we assume the existence of a temperatureindependent shift of rv-0.025%, K seems to show alinear relation with Xcorr , as shown in the inset of
Fig. 1 (b). This means that K follows the bulk susceptibility. However, the temperature independent shift ofrv - 0.025% is much higher than the well-known chemical shift. The origin of the shift has not yet beenclarified.
In order to clarify the whole picture of the anomalous enhancement of muon spin relaxation of quantum
systems, further study is necessary.
References
1) A. Fukaya et al.: Hyperfine Interact. 120/121, 619(1999).

105

RIKEN Accel. Prog. Rep. 33 (2000)

Muon Spin Resonance Study on an Organic Radical
TEMPO Derivative
S. Ohira, T. Ishida,* T. Nogami,* 1. Watanabe, and K . Nagamine
Organic radical magnets with a 2,2,6,6-tetramethylpiperidin-1-yloxyl (TEMPO) group have been developed, and their magnetic properties have been studied
by various methods. 1 ,2) The crystal structures of thesesystems are known to have a strongly two-dimensional(2D) arrangement of nitronyl radicals, which are localized on each N-O site and contribute to the magnetism.
We have previously carried out muon spin relaxation(I-LSR) studies on some TEMPO derivatives in order tomicroscopically observe magnetic transition and critical phenomena. 3 ,4) However, the I-LSR time spectra oforganic materials are sometimes difficult to interpretbecause it is suggested in general that a muonium or
muonium-like radical state tends to form in molecularbased materials, namely, muons experiencing large hyperfine fields exist. These components are the so-calledparamagnetic muons. In order to clarify the muon sites
in the TEMPO derivatives and to observe behavior forjust a diamagnetic muon by distinguishing it from theparamagnetic one, a muon spin resonance study witha radio-frequency field (RF-I-LSR) was carried out on
4-(p-chlorobenzylideneamino)-TEMPO (Fig. 1).
The experiment was carried out at the RIKEN-RAL
Muon Facility in the UK. Single crystals were preparedand mounted on a mylar sheet so that the a-axis wasperpendicular to the longitudinal field, H o, which wasapplied along the initial spin direction of the muon.
The RF field was applied perpendicular both to H oand to the a-axis with a frequency of 52.8 MHz.
The muon spin resonance in a diamagnetic environment was observed in the time evolution of themuon spin polarization. Figure 2 shows the resonancecurves at 2.5 K, 5 K and 270 K. The double ratio
is defined as A on / A off , where A on and A off are theasymmetries under the conditions where the RF
power is on and off, respectively. One resonance peak
was observed at each temperature, and a shift ofthe peak position was observed. The shift provides
information about the hyperfine field at the muonsite, A~f' Although some possible positions of the
diamagnetic muon are suggested from theoretical
calculations,5) no fine structures were observed in
the resonance curves.
The observed shift is expected to be a paramagnetic shift. The hyper fine

University of Electro-Communications
106

CI-{ >-CH~A

N~-O'

Fig. 1. Molecular structure of 4-(p-chlorobenzylideneamino)-TEMPO.

1.0

0

:;:;

0 .8

cO
~

II)

:c
~

0.6

0

6.: 2.5KCl. : 5K

0 .4

0: 270K

0 .2

3860

3880

3900
H0

3920

3940

3960

[G]

Fig. 2. Resonance curves at 2.5 K, 5 K and 270 K. The
muon spin resonance in a diamagnetic environment wasobserved.

field at the muon site was found to be approximately
115 G / I-LB from the plot of the shift against the susceptibility (K -X plot). The order of the hyperfine field iscomparable with the internal magnetic field observedin our previous ZF-I-LSR ("-'230 G),3) though the hyperfine field value is half that of the internal field value.
References
1)
2)
3)
4)
5)

M. Yasui et al.: Mol. Cryst. Liq. Cryst. 279, 77 (1996).
T . Nogami et al.: Chern. Lett. 1995, 635.
R. Imachi et al.: Chern. Lett. 1997, 233.
S. Ohira et al.: RIKEN Rev., No. 20, p. 48 (1999).
J. Jeong et al.: Physica B, in press.

RIKEN Accel. Prog. Rep. 33 (2000)

Intra- and Inter-molecular Electron Transfer in Cytochrome c andMyoglobin Observed by the Muon Spin Relaxation Method
K. Nagamine, F. 1. Pratt, S. Ohira, 1. Watanabe, K. Ishida, S. N. Nakamura, and T. Matsuzaki
Electron transfer processes in macromolecules, suchas the transfer in proteins, are an important part ofmany biological phenomena. In order to understandthe details of electron transport it is very important touse methods that provide information at a microscopic
level.
Among various types of proteins, cytochrome c has
attracted much attention, since it plays an essential
role in the respiratory electron transport chain in mitochondria, occupying a position next to the final processof the cycle, in which it transfers electrons to the surrounding oxidase complexes. Also, myoglobin is known
to serve an important role in oxygen transport and it
has a basic molecular structure similar to an electrontransfer protein.
In order to obtain microscopic information on electron transfer in the macromolecule, the muon spin relaxation (J..LSR) method offers great potential. During
the slowing process, the injected J..L+ picks up one electron to form a neutral atomic state called muonium,
which is in many ways analogous to a hydrogen atom.
The muonium is then thermalized followed by chemical bonding to a reactive site on the molecule. Then,
depending upon the nature of the molecule, the electron brought-in by the J..L+ can take on several characteristic behaviors, including localization to form aradical state and/or a linear motion along the molecular chain. These behaviors, by setting a time origin ofelectron movement, can be detected most sensitively
by measuring the spin relaxation process of the J..L + ,which occurs through a magnetic interaction between
the J..L+ and the moving electron produced by the J..L+
itself, using the J..LSR method.
Progress has been made in the theoretical understanding of this paramagnetic relaxation process by
Risch and Kehr who considered the direct stochastic treatment of the random walk process of a spin
which is rapidly diffusing along a topologically onedimensional chain. I) An error-function-type longitudinal relaxation function (hereafter called the R-K function), G(t) = exp(ft) erfc(ft)I/2, was proposed forAtmax » 1, where A is the electron spin flip rate, t max
the experimental time scale and f a relaxation parameter. In this theoretical treatment, f is proportional
to l/B ext .
Experiments on the J..L + relaxation in cytochromec and myoglobin have been conducted using an intense pulsed beam (70 ns pulses at 50 Hz repetitionrate) of 4 MeV J..L+ at the RlKEN-RAL Muon Facility at the Rutherford Appleton Laboratory, UK. The
cytochrome c used here is Fe(3+) type in a poly-

crystalline powder form extracted from horse heart(Wako Chemical product), while myoglobin was extracted from horse muscle (Sigma Co., Ltd.).
At each of the measurement temperatures, the J..L+
relaxation function was found to have an external fielddependence in the cases of cytochrome c with Fe(3+)
and myoglobin. The observed relaxation functions
G(t) were fitted with the R-K function,l) and the longitudinal relaxation parameter r obtained at various
temperatures were seen to decrease monotonically withincreasing B ext . On closer inspection of the Bext dependence of f, there were two components: (1) a region of weak field dependence (lower field) and (2) a(Bext)-I-dependent region (higher field). The latterregion exhibits the characteristic J..L+ spin relaxation
behavior due to the linear motion of a paramagnetic
electron. The critical field (hereafter, we refer to thisas the cutoff field) where the second region takes overfrom the first region has a significant temperature dependence; the cutoff field is seen to reduce with decreasing temperature.

•

-

o

......... Myoglobin

Cytochrome c

,-..

'~
D....

2

.....<I..........O .......... ··· .. ···..,···· ...... · ......· .. · .. •··· ..· .. · .. ·· · ..Il3

0.3£...................
0.OQ4

0.006

X
············· ..····1..........

0.008

0.1

0.01

11 T (1('1)

Fig. 1. The upper plot shows the temperature dependence of the parallel diffusion rate of an electron incytochrome c and myoglobin derived from the B- 1 _dependent part of the relaxation parameter. The lower
plot shows the perpendicular diffusion rate, derived
from the cutoff field, plotted against inverse temperature.

107

All of these results lead to the following microscopic
picture of the electron transfer process for the muoninjected electron in cytochrome c and myoglobin.
(1) Topologically linear motion exists along thechain of the cytochrome c.
(2) The intersite diffusion rate along chain D II , which
can be obtained from the measured r and the hyperfine coupling constant (500 MHz) estimated from therecovery curve of the initial asymmetry, becomes of theorder of 10 12 rad/s and almost temperature independent (Fig. 1).
(3) The cutoff process represents departure on along time scale from the topologically one-dimensional
diffusion which occurs on a short time scale. Depending upon the temperature region, the obtained
D..L in cytochrome c is dominated by two different
processes , as seen in the temperature dependence

108(Fig. 1); the characteristic change at 200 K of the
D..L seems to be related to the well-known structuralchange of some proteins, which has been suggested to
be a glass-like transition. On the other hand, D..L in
myoglobin shows only one component , reflecting th~different protein dynamics of this molecule for interchain electron trasfer.
The most important unknown pieces of information
are the distribution of the locations of the J.-L+ bondingsites and the corresponding electronic structure around
the J.-L+ at the site where the electron begins its linear
motion. For this purpose, as reported later, muon spin
RF resonance has been conducted on the J.-L+ in both
cytochrome c and myoglobin.
References
1) R. Risch and K . W. Kehr: Phys. Rev. B 46,5246 (1992).

3. Radiochemistry and Nuclear Chemistry

RIKEN Accel. Prog. Rep. 33 (2000)

In-beam Mossbauer Study of 51Mn/51Fe in Si Following
Projectile Fragmentation and Implantation
Y. Kobayashi, Y. Yoshida, A. Yoshida, Y. Watanabe, K. Hayakawa,* K. Yukihira,* F. Shimura,* and F. Ambe
. A radioactive isotope beam (RI beam) produced asa secondary beam after projectile fragmentation of nuclei is becoming very attractive in materials science
research. The combined on-line technique of ion implantation using an energetic RI-beam and Mossbauer
spectroscopy provides unique features in contrast
to conventional-implantation Mossbauer-effect studies
and in-beam Mossbauer spectroscopy. The implantation energy of the secondary RI-beam reaches GeV levels , i.e. , several orders of magnitude higher than thoseused in conventional implantation. Thus , it is possible to implant Mossbauer probes into hundreds of /-Lm
depth with a straggling range of a few /-Lm. In addition, we may be able to vary the range of the measuring
time after implantation using different nuclear probes.
In the case of 57Mn, for instance, which decays to 57Fe
with a half-life of 1.45 min, a Mossbauer measurement
can be started about 2 minutes after implantation.
In the present study, 57Mn ions were implanted intoa lightly B-doped FZ-Si crystal. We have succeeded in
obtaining well-resolved Mossbauer spectra of 57Fe in
Si following the decay of 57Mn between 30 and 296 K.
A secondary RI-beam of 57Mn was produced bya projectile-fragmentation reaction between a 59Co
primary beam and a 1-mm-thick Be production target. The energy and intensity of the primary beam
were 80 MeV/nucleon and about 200 enA, respectively. The 57Mn beam was directly implanted into
the Si sample after passing through an Al degrader.
The total dose was about 2 x 10 10 57Mn ions. Twoparallel-plate avalanche counters (PPAC) with 57Fe_
enriched stainless-steel foil, which were mounted on the
Mossbauer transducers, were used for ,-ray detection.
According to TRIM1) calculation, the projected
range of 57Mn nuclei was estimated to be 150 /-Lm fromthe surface. The vacancy concentration was 6.7 x 10- 4/ A/ion, which was much lower than that in the case of
the low-energy implantation. 57Fe Mossbauer spectrain Si were measured at different temperatures between
30 and 296 K, as shown in Fig. 1. All spectra could be
fitted by two singlets of components (A) and (B). The
component (A) at 296 K , which has an isomer shift of
0.86(2) mm/s and an area fraction of 0.59, can be assigned to interstitial Fe atoms in Si. The same component was also observed in an in-beam experiment using
Coulomb excitation and recoil implantation. 2 ) On theother hand , the component (B) has an isomer shift of-0.05( 4) mm/s , which can be attributed to Fe atoms
at the substitutional sites in Si by the calculation of
Shizuoka Institute of Science and Technology

110

100
110

!
f

~o 100 ~

i

110!

E 100

~ f
110

1QO

110

~

1 ~

1

30K

100t-1/ft~'I~II~I~~=1~~}==t=~91!"t~lt~tt~gt!!t~ttQt~lltfitt!~~ ' i . t' '!i (f .f!-3

-2

-1

0

1

2

3

Velocity (mm/s)
Fig. 1. Mossbauer spectra of 57Fej57Mn implanted into theSi sample, obtained between 296 K and 30 K.

o(Fesub.) = -0.064 mm/s. 3 ) The area fraction of thecomponent (A) did not change at temperatures below
296 K. This means that 60% of the 57Fe atoms were
ultimately at the interstitial sites in Si and 40% at thesubstitutional sites.
The FWHM of component (B) increased with decreasing temperature below 150 K, so it was considered
to have a tendency to be a doublet at low temperatures due to the interaction with vacancies introducedby irradiation with 57Mn ions. It is interesting to notethat none of the spectra measured in the present study
contain the doublet corresponding to an "amorphous"state observed in a former study 2) (0 = 0.23(1) mm/s,
r = 0.74(2), EQ = 0.83(1) mm/s at 300 K) . The difference seems to be either due to the different time
range of measurement after the implantation or due todifferent defect structures around the probes.
Since a secondary RI beam produced via a
projectile-fragmentation reaction still maintains alarge momentum from the energetic primary beam,
one might think that the measured spectrum would bestrongly affected by the radiation damage produced
109during the slowing process of such energetic ions in
the probes. However, we observed well-resolved spectra, which can be analyzed in terms of two components
corresponding to the Fe atoms at the interstitial andsubstitutional sites. Accordingly, this method offers
easy analysis to a wide variety of Mossbauer spectroscopic probes, which provide atomistic information regarding physical quantities at different types of sites

110of the probe atoms in a lattice immediately after implantation.
References
1) J. P. Biersack and L. Haggmark: Nucl. Instrum. Methods 174, 257 (1980).
2) P. Schwalbach et al.: Phys. Rev. Lett. 64 , 1274 (1990).
3) G. Langouche: Hyp. Interact. 72, 217 (1992).

RIKEN Accel. Prog. Rep. 33 (2000)

Biological Transport of the Various Trace Elements in
the Pregnant Rats and Fetus
S. Enomoto, R. Hirunuma, H. Tamano , and Y. Kawamura
The placenta functions as a barrier between fetus
and mother, providing regulation of heat exchange,
respiration, nutrition, and excretion for the fetus.
There is limited information on the transport of traceelements from the mother to the fetus.
The multitracer technique is useful tool for
metabolic studies of trace elements and can containmany isotopes simultaneously. In this paper, the multit racer technique was applied to study the maternaltransfer of trace elements via the placenta to the fetus.
The radioactive multitracer solution was preparedfrom an Ag target irradiated with a 135 MeV /nudeon
12C, 14N, or 16 0 beam accelerated in the RIKEN Ring
Cyclotron. After chemical separation, the multitracerphysiological saline was injected to 17 days pregnant
Wistar rats. The pregnant rats were sacrificed under
ether anesthesia at 3, 12, 24 and 48 hours after injection. The maternal bloods, placentas, fetuses , fetus brains, and amniotic fluids were taken out fromthe rats and collected. The radioactivities were determined by ,-ray spectrometry using pure Ge detectors.
In this experiment, the multitraer solution contained
the following nuclides: 7Be, 22Na, 46Sc , 48V, 52 Mn,
59Fe, 56CO, 65Zn, 67 Ga, 74 As, 75S e , 84Rb, 85S r , 87y,
88Z r , 96Tc and 103Ru. We examined the time dependence of the uptake of various elements. From theseresults, we observed a significant difference in timedependency between each element. The elements weredivided into three groups (Fig. 1). In the first group,
Be, V, As, Ru, Y, Zr and Tc were transported to theplacenta from the maternal blood and only accumulates in the placenta. In the second group, N a, Sc, Co,

Matenal Blood

Placenta

Amniotic Fluid

Be2+
Fetus

Na+ Sc3+--~c"~
Accumulation

0-'

sr2+
Ga3+

Mn2+ F.,3+
Se032.
Zn2+- - i t -..... Rb+

Placenta

Fig. 1. Transport of trace elements from the maternal
blood to the placenta and fetus. Chemical forms ofvarious tracers in saline are indicated.

Ga, and Sr were transported to the placenta from thematernal blood and accumulates in the placenta, fetus,
and amniotic fluid. In the third group elements, Mn,
Fe, Se, Zn , and Rb were transported to the' placenta
from the maternal blood and mainly accumulates in
the fetus. Based on the above results, it was consideredthat the placenta is highly selective because essential
elements such as those in the third group are readilytransported across placenta/membranes to the growing fetus, whereas nonessential metals such as those in
the first group hardly penetrated the placental barrierthat protects the fetus from toxic effects.

111

RIKEN Accel. Prog. Rep . 33 (2000)

Uptake of Zinc and Other Trace Metals In Tumor-bearing Murines
H. Tamano, S. Enomoto, and A. Takeda
Zinc is an important nutrient for both normal andmalignant tissues. 1) The growth of malignant tissue iseffectively inhibited by zinc deprivation. 2 ,3) Therefore,a host response of zinc mobilization might influence
the proliferation of malignant tissue, and a competition for zinc might occur between host and malignant
tissue. Clarification of the zinc mobilization pattern
after tumor transplantation is important for an understanding of zinc homeostasis. In the present study,
the zinc uptake in tumor-bearing murines was examined. Furthermore, uptakes of other trace elements intumor-bearing mice were also examined by the multitracer technique.
Male rats of the Donryu strain (160-180 g) were
subcutaneously (s.c.) transplanted with ascitic fluid
from rats with hepatoma (1 x 10 7 /ml, 0.2 ml/rat)
and male mice of the ddY strain (25-30 g) were s.c.
transplanted with Ehrlich carcinoma cells (1 x 10 7 /ml,
0.2 ml/mice). Ten days after the tumor transplantation, radiolabeled zinc chloride (65 ZnCl 2 purchasedfrom Du Pont/NEN Research products, Boston, MA)
in 0.1 M acetate buffer (pH 4.0) was intravenously (i.v.)
injected into the control and tumor-bearing murines.
One hour after the injection, blood was drawn andthe tissues to be studied were excised. The radioactivity level of the specimens was determined using a,),-counter. As shown by the data in Fig. 1, one hour
after the i.v. injection, the 65Zn uptake by the tumor
was lower than that by liver, kidney and pancreas. On
the other hand, the hepatic 65Zn level in tumor-bearing
rats was significantly higher than that in control rats,
while the blood 65Zn level in the former was significantly lower than that in the latter. Similar results
were also observed in tumor-bearing mice.
The uptake of other radioactive metals, which wereprepared as a multitracer solution, was determined in
Ehrlich carcinoma-bearing and control mice (7 days
after transplantation) 3, 24 and 48 hours after the injection. The multitracer solution contained radioactive

112

Pancreas m~~..;.:.r;.;,;",;,;~
MuscleBrain[J Control

Blood

mTumor-bearing

Tumor

o

2

3

4

65Z n (%doselg tissue)

Fig. 1. 65Zn uptake by tissues in rats 10 days after thetransplantation of AH7974F (*, P < 0.05).
Be, Sc, Zn, Rb, Y, Zr, Te, Ba, Hf, Ir, Pt, Ce, Eu , Gd,
Yb and Lu. The ')'-ray spectra in excised tissues were
measured using a germanium detector. At 48 hours
after the injection, the uptake of some radionuclides,
e.g., Sc and Y, by the tumor was relatively high compared to that in normal tissues such as the liver, muscle
and blood.
In conclusion, these results suggest that, in tumorbearing murines, the Zn uptake is preferentially increased in the liver. Moreover , using the multitracer
technique, some rare earth elements were observed toaccumulate more in tumor tissue than in normal tissues.
References
1) B. L. Vallee and K. H. Falchuk: Physiol. Rev. 73 , 79
(1993).
2) D. T. Minkel, P. J. Dolhun, B. L. Calhoun, L. A. Saryan,
and D. H. Petering: Cancer Res. 39, 2451 (1979).
3) L. A. Saryan, D. T. Minkel, P. J. Dolhun, B. L. Calhoun,
S. Wielgus, M. Schaller, and D. H. Petering: Cancer
Res. 39, 2457 (1979).

RIKEN Accel. Prog. Rep. 33 (2000)

Biological Tissue Distribution of Vanadium in STZ-Induced
Diabetic Rats: Simultaneous Tracing of V, Cr, Mn, Fe,
Co, Zn, and Se Using a Radioactive Multitracer
H. Yasui, T. Takino, J. Fugono, R. Hirunuma, S. Enomoto, and H. Sakurai
The biological actions of vanadium have been investigated by many researchers. The insulin-mimetic
effect of vanadium is the most remarkable amongits several biological actions. Recently, vanadyl ions(+4 oxidation state of vanadium) and its complexes
have been shown to normalize the blood glucose
levels in streptozotocin-induced diabetic rats (STZinduced diabetic rats). We have carried out experiments to find vanadyl complexes with more effective
insulin-mimetic activity and prepare less toxic complexes using various types of coordination modes. 1)
Vanadyl-methylpicolinate complex (VO-MPA) containing VO(N 2 0 2 ) exhibited more effective and longer
lasting insulin-mimetic activities and less toxicity after oral administration than other complexes in the invivo experiments. 2 )In the present investigation of the metabolism oftrace elements, we studied the biological tissue distribution of vanadium as well as other trace elements
in normal, STZ-induced diabetic , and vanadyl sulfate (VS)-administered rats, to elucidate the relationship between the blood glucose normalizing effects andglobal disposition of trace elements including vanadium. In this experiment, we used VS as a positive
control compound to examine the effects of vanadiumon the tissue distribution of trace elements before testing VO-MPA.
A multitracer solution containing the radioisotopesof 20 elements was prepared from an Ag target irradiated by a heavy-ion beam of 135 MeV/nucleon accelerated by the RIKEN Ring Cyclotron. Vanadyl sulfate (VOS04 . 4H 2 0) was purchased and used as the
positive control compound. Male Wistar rats (bodywt. rv250 g) were divided in three groups, that is ,normal, STZ-induced diabetic, and VS-administeredgroups. Rats treated with VS were administered three
intraperitoneal (i.p.) injections of VOS0 4 at doses of
10 mgV /kg body weight once a day for three days.
The multitracer solution was injected intraperitoneally(1.0 ml/rat). The rats were sacrificed at 12, 24 and72 hrs after the administration, and blood samples
were collected and selected organs (liver, kidney, muscle, and bone) were removed from the rats in eachgroup (n = 4). The radioactivity levels in their blood,
liver, kidney, muscle, and bone was determined by "1ray spectrometry. The observed "I-rays were analyzed
in terms of their energies and half-lives. The individual behavior of Be, Na, Ca, Sc, V, Cr, Mn, Fe1 Co, Zn,
Ga, As, Se, Rb, Sr, Y, Zr, Tc, Ru, and Rh was examined. The obtained time courses of amount of eachof the trace element in each organ were evaluated bynoncompartmental analysis (moment analysis). Furthermore, we developed a novel evaluation method to
directly compare the biodistribution of trace elements
in normal rats with that in STZ-induced diabetic rats,
using the ratio plots of tissue uptake (% of dose) of
every trace element.
The mean tissue uptake rates of 48V by the four tissues and blood of the rats were determined. The highest uptake of 48V was observed in the kidney of allgroups. The uptake rates of 48V were observed to decrease with time except for that by the bone, which wasincreased at 72 hr in comparison with that at 12 and24 hrs. These results are in good agreement with ourprevious pharmacokinetic analyses of the tissue distribution of vanadyl compounds by means of neutron
activation analysis (NAA).
In addition, the amounts of other trace elements accumulated in the tissues were simultaneously determined by the radioactive multitracer technique. The
effect of preadministered VS on the accumulation of
trace elements in the tissues was most significant in
the bone. These results suggest that the accumulationof vanadium in the body may alter the global disposition and tissue distribution processes of several traceelements. Therefore the relationship between the antidiabetic activity of the vanadyl compounds and thebiobehavior of other essential trace elements must be
clarified in detail.
References
1) H. Sakurai, H. Watanabe, H. Tamura, H. Yasui, R.
Matsushita, and J. Takada: Inorg. Chim. Acta 283,
175 (1998).
2) S. Fujimoto , K. Fujii, H. Yasui, R. Matsushita, J.
Takada, and H. Sakurai: J. CHn. Biochem. Nutr. 23,
113 (1997).

113

RIKEN Accel. Prog. Rep. 33 (2000)

Metabolic Study of Trace Elements in Se-Deficient Rats (IV)
R. Hirunuma, K. Endo, and S. Enomoto
Selenium is an essential element to mammals but
poisonous at high doses. 1) It was reported that Se
exhibits a competitive or synergetic relationship withseveral elements such as Hg and Cd. 2 ,3) Therefore, thedistribution of other trace elements in various organs
is expected to be influenced by the amount of Se fed tomammals. However, no systematic study has been reported on the behavior of trace elements in Se-deficientrats. This paper describes the uptake and distributionof trace elements in Se-deficient rats by the multitracer
technique and instrumental neutron activation analysis (INAA).
Wistar male rats bred from fetal stage on a Sedeficient diet (produced by Oriental Yeast Co., Ltd.)
were used in these experiments as Se-deficient rats.
Control rats were fed with the Se-deficient diet supplemented with 0.2 ppm of Se (adequate level of Se fornormal growth).
In the first experiment, a multitracer solution containing various kinds of radionuclides was preparedfrom an Ag target irradiated with 14 N beam of
135 MeV/nucleon accelerated in the RIKEN Ring Cyclotron. The multitracer solution was injected intravenously into each rat . The Se-deficient and control
rats were sacrificed at 3, 12, 24, and 72 hours after
injection, and the radioactivities in the brain, liver,kidney, spleen, and testicles were measured using highpurity Ge detectors. The distribution of Se, Fe, and
Zn in various organs of the rats was evaluated.
In the second experiment, the 12-week-old Sedeficient and control rats were sacrificed and the organs
were obtained. Each organ was lyophilized, pulverized,
and then irradiated with the thermal neutron flux of

1.5 X 10 12 n cm- 2 s-1 at F-24C in TRIGA II nuclear
reactor of Rikkyo University.
Table 1 shows the Se, Fe, and Zn concentration invarious organs of each rat determined by INAA. As
for the Se-deficient rats, only a small amount of Se
was found in all organs. Iron concentration in the liverand spleen of Se-deficient rats was higher than that ofcontrol ones. However, no difference in the concentration of Zn between Se-deficient and control rats wasobserved.
Figure 1 shows the uptake of Se, Fe, and Zn invarious organs of the Se-deficier1t and control rats, as
determined by the multitracer technique. Influences
due to Se-deficiency were observed on the distribution
pattern of Se and Fe in various organs. The uptakeof Se was higher in the brain of the Se-deficient rats
than in that of the control ones. In the liver, theuptake of Se in the control rats was higher than thatin the Se-deficient ones. In the case of control rats,
the uptake of Se in the liver was much higher thanthat in the brain. However , the uptake in the liver was
Table 1. Concentration (ppm) of Se, Fe, and Zn in variousorgans of Se-deficient and control rats.
Se
Se-deficient
ControlFe
Se-deficient
Control
Zn
Se-deficient
Control

Se ~ 2~rain 20~i~~ey 4°Biv~r
~ I

g.

10

~--'-x 20

X---X.)(-_·_-x
0 0 0o 20 40 (iO SO 0 20 40 60 SO () 20 40 60 80
Time (h)Time (h)Time (h)

Fe

Brain

KidneyLiver

SpleenTesticles

0.6±0.1
l.0±0.1

0.6±0.1
7.9±l.0

0.07±0.03
3.1±O.3

0.3±0.1
2.3±O.2

2.4±0.2
1O.3±1.4

Brain

KidneyLiver

SpleenTesticles

130±20160±24300±35258±26654±41452±452434±247
I43I±241157±1O150±13Brain

KidneyLiver

SpleenTesticles

6I±3
59±4

I 24±23
lOO±17

97±9
87±6

86±4
90±6

202±1O215±19:g""" ': T~"'"
I

.~

o

o 20 40 60 80
Time (h)4[aPleen-0- Se-deticient

2- 'X'" Controlc..

)E-._-Xo 20 40 60 !l0o-.---)(o 20 40 60 80
Time (h)zn~ :D"'" ':~ld~ :~'(:I :t:~1-

0 20 40 60 80
Time (h)

~20

::> 0

-"!

O~r-~~,.-...4°rzJiver

~

:3'

. __

10

*--~

0 0 0
o 20 40 60 80 () 20 40 60 SO () 20 40 60 80
Time (h)Time (h)Time (h)o 20 40 60 80
Time (h):T"tid"

0 20 40 60 80
Time (h)Fig. 1. Uptake of Se, Fe, and Zn in various organs of the Se-deficientand control rats.

114

almost comparative to that in the brain of Se-deficientrats. It is reported that a small quantity of Se fed
to Se-deficient rats is absorbed preferentially in thebrain over the liver. 1) It is considered that the results
described above are attributed to this reason. No
difference was detected in the uptake of Zn between
Se-deficient and control rats. On the other hand,
uptake of Fe in Se-deficient rats was higher thanthat in control ones. The uptake of Fe in the liver of
Se-deficient rats increased with time. The increasein Fe uptake by Se-deficient rats suggests an increasein Fe-containing proteins. The concentration of Fecontaining proteins, such as hemoglobin, transferrin,
and ferritin was measured in the serum of Se-deficientand control rats. The concentration of ferritin in Sedeficient rats was found to be high. The increase in
Fe uptake by Se-deficient rats caused an increase in
the concentration of Fe-binding proteins, such as ferritin. We suggest that ferritin in excessive amounts
promotes peroxidation of cell membranes that resultsin cell damage.
References
1) D. Behne et al.: Biochim. Biophys. Acta 966, 12 (1988).
2) T. Drano et al. : Biochem. Biophys. Res. Commun. 239,
862 (1997).
3) J. Gambhir and R . Nath: Indian J. Exp. Biol. 30, 597(1992).

115

RIKEN Accel. Prog. Rep. 33 (2000)

Distribution of Bio-Trace Elements in Cell Fraction of
Selenium-Deficient Rat Liver
K. Matsumoto, Y. Ueda,* K. Endo, R. Hirunuma, and S. Enomoto
Selenium (Se) is the essential trace element that
constitutes the active center of glutathione peroxidase(GSH-Px). It is believed that Se plays a protectiverole against oxidative stress in living organisms. On
the other hand , it is known that Se interacts withother metal ions in biological systems. For example,
the accumulation of iron (Fe) in Se-deficient rat liver,kidney, and spleen has already been reported in a previous paper, and we observed that Fe uptake increasedin Se-deficient rat liver. 1) However, the mechanism of
Fe accumulation in the liver of Se-deficient rats has
not yet been clarified. In living organisms, Fe constitutes the active center of catalase, cytochrome P-450 ,and xanthine oxidase, and is related to the digestionand synthesis of reactive oxygen species. Therefore,
the change of in vivo redox reaction valence due todecreased GSH-Px activity is expected to cause thechange of the Fe dynamics in Se-deficient rats.
In this experiment, using instrumental neutron activation analysis (INAA) and multitracer analysis(MTA) , we examined the dynamics of metal ions which
are related to in vivo redox regulation systems such as
Se, Fe, manganese (Mn), cobalt (Co) , and zinc (Zn) inliver cell fractions of Se-deficient rats.
Se-deficient and normal male Wistar rats (8 weeksold) were sacrificed by bleeding from the abdominal
aorta under anesthesia. Subsequently, the liver was
perfused with 0.9% NaCl. The liver was removed andhomogenized with a threefold volume of 1.15% KCl.
Then , nuclear (NU) , mitochondrial (MT) , microsomal(MC), and cytosolic (CS) fractions were separated bycentrifugation. In the INAA experiment, each fraction was lyophilized. Then, an aliquot of each powdered fraction was weighed and sealed in polyethylene.
Neutron irradiation was carried out in the TRIGA
II nuclear reactor of Rikkyo University. Bovine liver(NBS SRM 1577) was used as a standard sample. In
the MTA experiment, each cell fraction was prepared
2 days after intravenous administration of the multitracer. An aliquot of each wet fraction was put intoa plastic tube. The ,,-ray spectra of the INAA andMTA samples were measured with a high-purity Ge
semiconductor detector equipped with a multichannel
analyzer. In the present study, we focused our spectral
analysis only on Se, Co, Mn, Zn, and Fe.
The Se contents of the separated fractions of thenormal rats obtained by INAA were 2.5 ppm in MT,
1.5 ppm in MC, and 3.1 ppm in CS, respectively. In
contrast, the Se contents in all the separated fractionsof the liver homogenates of Se-deficient rats were below the detection limit , which was estimated to be
0.04 ppm in the dried sample as the upper limit for Se
under the present experimental conditions. The peakidentification of ,,-ray spectra was based on a criterionof grater than 3<1' (three times the standard deviationof the background counts).
The uptake of Se was determined using MTA. The
results indicated that the uptake (percentage to thestandard) of Se into each fraction of rat liver homogenates was not significantly different. This is believed to be due to the absence of a specific transportation system for Se.
The content of Co also decreased in Se-deficient rats
compared with the normal ones, and this was believed
to be due to the low content of Co in the diet. However ,MTA data indicated that the uptake of Co increasedin cell fractions other than CS , suggesting that theenhancement of the uptake was due to the supplement
effect because of the insufficient content of Co in the
Se-deficient diet.
The uptake of Mn into the MT, MC, and CS fractions of Se-deficient rats was lower than that of normal
rats except for increased uptake into the NU fraction.
The uptake of Zn into the CS fraction of Se-deficient
rats decreased, although the uptake of Zn into theother fractions increased. The INAA data indicatethat the contents of Mn and Zn in the MT and CS
fractions of liver were lower in Se-deficient rats thannormal rats. These two elements are known to be theactive centers of Mn-SOD and CU,Zn-SOD, and arelocated mainly in MT and CS fractions, respectively.
The lower uptake and contents of Mn in the MT fraction and Zn in the CS fraction of Se-deficient rat liver
may be responsible for the decrease of the SOD activity
in these cell fractions.
The content of Fe significantly increased in Sedeficient rats, especially in the MC fraction. This is believed to be due to the change of activity of cytochrome
P-450 which exists in the MC fraction. On the other
hand, if the Fe existed as free-ion form (or could be coordinated by easily exchangeable ligand molecules) , anincrease of hydroxyl radical synthesis through the Fenton reaction and peroxidation of the lipid membrane
could be expected. Although Fe uptake increased in
the MC fraction of Se-deficient rat liver, its increment
was not large (less than 0.2%).
References
1) R. Hirunuma et al.: J. Radioanal. Nucl. Chern. 239,
213 (1999).

Showa College of Pharmaceutical Sciences

116

RIKEN Accel. Prog. Rep. 33 (2000)

Effect of Dietary Selenium Species and Doses on the Organ
Distribution of Multitracer
Y. Shiobara, Y. Ogra, R. Hirunuma, S. Enomoto, and K. T. Suzuki
Selenium (Se) is an essential trace element for mammals, and both inorganic and organic Se can be utilized as a nutritional source by the body. Inorganic Se
in the form of selenite and selenate and organic Se in
the form of selenocysteine (SeCys) are reduced by glutathione and glutathione reductase and metabolized by,8-lyase, respectively, to the assumed key compound,selenide (H 2 Se). Selenide is, then, utilized for the synthesis of selenoproteins or excreted in urine and/or by
respiration after being methylated. On the other hand,selenomethionine (SeMet) taken up by the body is incorporated either into general proteins without being
distinguished from methionine or metabolized to selenide.
Our previous study showed that the chemical species
and concentration of Se in the diet influence the concentration of Se in hair, blood,1) liver and kidneys.
In particular, the Se concentration in hair, blood, liverand kidneys of rats fed with a SeMet-excessive diet was
higher than that of rats fed with a selenite-excessive
diet. Selenium has been known to interact with toxic
heavy metals (e. g., Hg and Cd) and to decrease thetoxicity of Se and other metals.
In the present study, effects of the chemical species
and concentration of Se in the diet on the uptake, distribution and excretion of other metals (Mn, Co, Zn,
Se and Hg) administered intravenously (iv) at a low
dose, were examined by the multitracer technique.
A multitracer solution containing radioiotopes of 17
elements (Be, Na, Ca, Sc, V, Cr , Mn, Fe, Co, Zn,
Ga, As, Se, Rb , Y, Zr and Tc) was prepared froman Ag target irradiated with a heavy-ion beam of
135 MeV/nucleon accelerated by the RIKEN Ring Cyclotron. Then, the multitracer solution was mixed witha 203Hg solution, and administered iv to rats at a doseof 0.2 ml/rat.
Male rats of the Wistar strain (4 weeks old) were fed
a Se-deficient (concentration of Se, less than 0.03 mg
Se/kg diet), selenite-adequate (0.2 mg Se/kg diet),selenite-excessive (2.0 mg Se/kg diet), SeMet-adequate(0.2 mg Se/kg diet) or SeMet-excessive (2.0 mg Se/kg
diet) diet for 2 weeks. At 6 weeks of age, all groups ofrats were administered a multitracer solution containing 203Hg, and sacrificed 96 hr after the injection. The
radio/activities in the organs (liver, kidneys, testes,
spleen and brain), whole blood, plasma, hair, urine
and feces were determined by [-ray spectrometry andthe observed [ rays were assigned in terms of their energies and half-lives to the individual behavior of Mn,
C9, Zn, Se and Hg.

Table 1. Effect of dietary Se on uptake of tracers (Mn andSe) in the liver and kidneys.
liver (% of recovery)
group
Se-deficient
Selenite-adequate

kidney (% of recovery)

MnSe

6.45 ± 0.07
7.99:1: 0.43*

5.16 ± 0.13
8.12 ± 0.26*

Mn
3.38 ± 0.13
3.15 ± 0.25

Se
5.08 ± 0.25
3.38 ± 0.17*

Selenite-excessive 5.74 ± 0.22*

2.41 ± 0.20*

2.24 ± 0.37*

0.94 ± 0.07*

SeMet-adequate

7.31 ± 0.47

7.52:1: 0.05*

2.86 ± 0.17*

SeMet-excessive

5.58 ± 1.15

2.30 ± 0.19*

2.38 ± 0.35*

2.91 ± 0.11 *0.90:1: 0.10**Significant difference from the Se-deficient group at p<0.05 (n=3).

The behavior of radioisotope Se in each group
showed that the 75Se distribution levels in the plasma,kidneys, testes, spleen and brain were inversely proportional to the dietary Se concentration. However, inthe liver and blood, the 75Se recovery of the adequategroups were higher than that of the deficient group.
These results were assumed to be caused by the dilution of 75Se with dietary Se. The behavior of theradioisotope Hg in each group showed that the 203Hg
distribution level in the liver was inversely proportional
to the dietary Se concentration.
With respect to Zn and Co, there was almost no
influence on the uptake, distribution and excretion by
the chemical species or concentrations of the dietarySe.
In the liver, kidneys, testes, spleen, plasma and feces, the distribution of Mn was similar to that of 75Se
(Table 1). In other words, the Mn distribution levelin the kidneys, testes, spleen, plasma and feces wasinversely proportional to the dietary Se concentration.
The mechanism underlying the similarity of the Mn
uptake to that of 75Se is not clear at present becauseof the diverse biological functions of Mn in the body.
However, the accelerated uptake of Mn may be relatedto oxidative stress under Se-deficient conditions.
Statistical analysis was performed by two-way
AN OVA to compare the mean values between excessiveor adequate and deficient groups.
In conclusion, although the effects of chemical
species of dietary Se on the distributions of Zn, Co,
Mn, Se and Hg were not observed, the effects of deffering concentrations of dietary Se on the distributions of
Se, Hg and Mn were demonstrated.
References
1) Y. Shiobara et al.: Toxicol. Appl. Pharmacol. 152 , 309(1998).

117

RIKEN Accel. Prog. Rep. 33 (2000)

Uptake Rates of Trace Elements in Zn-Deficient MiceT. Ohyama, T. Yoshida, M. Iwama, M. Yanaga, M. Noguchi,*l T. Omori,*2 R. Hirunuma, and S. Enomoto
Zinc is one of the most essential trace elements in living organisms, and is second only to iron in abundance.
More than 300 Zn-proteins have been identified, anddeficiency of this element leads to various symptoms,
such as growth retardation, hypogonadism, immunodeficiency and alopecia.
The concentrations of Zn and other trace elements invarious organs and tissues of Zn-deficient and control
mice were determined by instrumental neutron activation analysis (INAA) .1,2) Zinc concentrations in thebone and pancreas of Zn-deficient mice were significantly lower than those in control mice, although thosein the other organs and tissues of Zn-deficient mice
were not. It is believed that Zn is supplied from thebone to other organs, where it supports various functions. The Co concentrations in Zn-deficient mice, in
however, were significantly increased in all organs andtissues.
The multitracer technique is a suitable method to investigate the behavior of these trace elements in vivo.
This technique enables us to trace various elements simultaneously under identical conditions. In this study,
the uptake rates of trace elements in Zn-deficient mice
were examined using the multitracer technique andcompared with the results obtained previously using
INAA.
Seven-week-old male mice of the ICR strain werepurchased and fed with a commercial diet and tap
water. After one week, they were divided into twogroups. The Zn-deficient group was fed Zn-deficient
diet and distilled water (Zn-deficient mice), and thecontrol group was fed control diet (the control dietconsisted of the raw materials for the Zn-deficient dietand Zn in the form of zinc car bonate) and distilledwater (control mice). After three weeks, a multitracer
physiological saline solution, which was prepared from
Ag foil by a previously reported method,3) was injected
intraperitoneally into each mouse (0.2 ml/mouse). Six,
24 or 72 hours after the injection, they were sacrificed under diethyl ether anesthesia. Then, the brain,
liver, kidney, pancreas, spleen, testis, skeletal muscle,bone and skin were removed. These organs and tissues were weighed immediately and their radioactivity
levels were measured with HP Ge detectors.
The uptake rates of various trace elements by thebone are shown in Fig. 1. The uptake rate of Zn 24 and72 hours after the injection of Zn in Zn-deficient micedecreased significantly compared with that in control
mice. On the other hand, the uptake rates of Zn in
*1

*2

118

Department of Biology and Geosciences, Shizuoka University
Radiochemistry Research Laboratory, Shizuoka University

i:~::~':~o20

40 60 80 100
Tim. (h)

0

20

40

60

80 100

0

20

40

60

80 100:~:~::EJ
o

20

40

60

80

100

0

20

40

60

80

100

0

20

40

60

80 100

o

20

40

60

80 100

0

20

40

60

80

100

0

20

40

60

80

iE:J ::EJ :E1

100

Fig. 1. Uptake rates of trace elements by the bone of Zndeficient mice (0) and control mice(.) 6-72 hours after
intraperitoneally injection of a multitracer saline solu-

tion.
the liver, kidney and spleen in Zn-deficient mice werehigher than those in control mice (data not shown), although the Zn concentrations determined by INAA inthese organs of Zn-deficient mice were similar to thosein control mice. These findings suggest that Zn is not
only transferred from the bone to the liver, kidney andspleen, but is also taken up by these organs preferentially. Our previous works have shown that the Co concentrations in all the organs and tissues of Zn-deficient
mice were higher than those in control mice. 1,2) However, there were no significant differences in the uptake
rates of Co in most of the organs and tissues between
Zn-deficient mice and control mice. Our experiments
using the INAA method showed that the accumulation of Co in Zn-deficient mice was saturated withina three-week treatment period. This might be one ofreasons why no significant differences were recognizedin the uptake rates of Co. It was found, furthermore,that the behavior of Sr was similar to that of V and
Y in both Zn-deficient and control mice, as shown in
Fig. 1. However, the uptake rate of the typical boneseeking element, Sr, was decreased in Zn-deficient micewith the passage of time after injection.
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., inpress.
3) M. Yanaga, T. Ohyama, M. Iwama, T. Yoshida, M.
Noguchi, T. Omori, R. Hirunuma, and S. Enomoto:
RIKEN Accel. Prog. Rep. 32, 127 (1999).

RIKEN Accel. Prog. Rep. 33 (2000)

Characterization of Manganese Transport System Using
Cadmium-Resistant Metallothionein-Null Cells
T. Yanagiya, N. Imura,*l S. Enomoto, Y. Kondo,*2 and S. Himeno
Cadmium (Cd) is an environmental pollutant thathas adverse effects on cells and animals. Despite thetoxic effects of Cd in animals being well documented,
the transport mechanisms of Cd are poorly understood. Previously, we reported that a Cd-resistantcell line (Cd-rB5) derived from immortalized metallothionein (MT)-null fibroblasts exhibited a marked
decrease in cadmium uptake as compared with thatby the parental MT-null cells, suggesting that changes
in the cadmium transport mechanism are responsible
for resistance to cadmium. 1) Furthermore, when a multitracer solution was added to the medium of Cd-rB5
and parental cells, only Mn uptake was reduced in CdrB5. 2) However, the reduced uptake of Mn was observed only at low concentrations, suggesting that ahigh-affinity component of the Mn transport system isdown regulated in Cd-rB5 cells. 2)
In the present study, to investigate the substratespecificity of the high-affinity Cd-Mn transporter, we
examined the inhibitory effects of metal ions such as
Zn, Co, Ni, Fe and Cu on the cellular uptake of Cd and
Mn in parental cells. As shown in Fig. 1, the uptakeof Cd was inhibited by Zn as well as Mn, but not by
Co, Ni, Fe and Cu. Similary, cellular uptake of Mn
14

£

>

-

(5
U
«S

12

10

L-

.Q

~

L-

"0

0

0>

C
0

8

U

'0

6

~
~

4

0

2

(-)

Mn Zn

Co

Ni

Fe

MetalsFig. 1. Effects of various metals on the uptake of Cd byparental cells. Parental cells were exposed to 0.03 /LM[109Cd]-CdCh in the presence of 5-fold excess amountsof MnCh, ZnCh, CoCh, NiCh, FeS04 or CuCh for
15 min. Significantly different values were obtained in
the absence of metal inhibitors (**, p < 0.01).

*1
*2

A

B
15

15
c:

c:

'iii
[

'iii

~ 10

10

.§

'"

~

(5

(5

! 5

E

.e 5
'0

~

o

~s

&0 &s
pH

~o

~5

ao

o~~~--~~~~~~o~s&0 &s ~o

~5

ao as

pH

Fig. 2. pH-dependency of Cd and Mn uptake by CdrB5 and parental cells. A: Cd-rB5 (closed circles) andparental cells (open circles) were exposed to 0.03 /LM[109Cd]-CdCh for 15 min in the medium adjusted to a
specific pH. B: Cd-rB5 (closed circles) and parental cells(open circles) were exposed to 0.03 /LM [54 Mn]-MnCh
for 15 min in the medium adjusted to a specific pH.
was inhibited by Zn and Cd, but not by Co, Ni, Fe andCu (data not shown). These results suggest that thehigh-affinity Cd-Mn transport system may, at least inpart, involve the mechanism for Zn transport.
Recently, Gunshin et al. reported that a divalent
metal transporter 1 (DMT1), a proton symporter, isinvolved in Fe, Zn, Mn, Cd, Co, Ni, Cu and Pb incorporation into the intestinal mucosa. 3 ) Since DMT1 cantransport metal ions only at acidic pH, we examined
the pH dependency of Cd and Mn uptake by Cd-rB5
and parental cells. As shown in Fig. 2, maximal uptakeof Cd and Mn was observed at neutral pH in parental
cells, but no uptake of either metal was observed at
physiological pH in Cd-rB5. These findings suggestthat the high-affinity Cd-Mn transporter that is suppressed in Cd-rB5 cells is not DMTl.
Application of the multitracer technique has enabled us to detect the transport system for both
Mn and Cd.
Further study is needed to elucidate the molecular mechanisms of Cd and Mn
transport.
References
1) T. Yanagiya et al.: Life Sci. 65, PL177 (1999).
2) T. Yanagiya et al.: J. Pharmacol. Exp. Thrap., in press.
3) H. Gunshin et al.: Nature 388, 482 (1997).

School of Pharmaceutical Sciences, Kitasato University
Department of Urology, Nippon Medical School

119

RIKEN Accel. Prog. Rep. 33 (2000)

Biobehavior of Multitracers in the Brain and Other Organs of
1-, 3- and 8-Week-Old MiceT. Tarohda,*1 R. Amano, K. Sakamoto,·2 and S. Enomoto
Manganese, copper and zinc are known for theirnutritional roles in animals; Mn definitely and possibly Cu and Zn have important biological functions
in various metabolic processes. 1) Homeostasis and interactions among these microessential elements during
growth and developmental processes remain to be thoroughly studied. In this study, we focused on the transportation and retention of Mn , Zn, Se and Rb trace elements in the brain, liver, pancreas, spleen and kidney,utilizing a radioactive multitracer technique developedby us.
A carrier-free multitracer was obtained from an Ag(purity: more than 99.99%) target irradiated by the
12C-ion 135 MeV/ nucleon beam from RIKEN Ring
Cyclotron . The multitracer solution, which was prepared according to the method of Ambe et al. 2- 4 ) at
the Radioisotope Center of Kanazawa University, contained 17 radioisotopes of 14 elements. The physiological saline solution (0.9% NaCI in O.OOIN HCI, pH 2-3)
containing the multitracer was prepared for intraperitoneal (ip) injection. Table 1 lists the radioisotope
specifications of a O.l-ml multitracer solution injected
into a 5-g mouse.
Sixty normal ICR mice used in this experiment weredivided into three groups according to the age (1-, 3and 8-week-old mice) An appropriate amount of themultitracer solution (0.1 ml/ 5-g weight of mouse) was
injected intraperitoneally into each mouse. At 6, 12, 24
and 48 hr after ip injection, the mice were dissected andperfused with 0.9% NaCI solution under ether anesthesia. The brain, liver , pancreas, spleen and kidney samples were excised, and t hen weighed immediately andTable 1. Specificat ions of a 0.1 ml multitracer solution
injected into a 5-g m ouse .
Radioactive tracer
'Be
4BSC
48

V

51Cr
52Mn
54

Mn

58

CO
59 Fe

85

Zn

'5 S ..

83Rb
84Rb
85

88
89

Sr
Zr

Zr
!I'Ru
lO1mRh

*1

*2

1.20

Half life (d )Radioactivi9! ( kBg) Estimated mass ( E!g: )53.29
83.8 1
15.97
27.70
5.59
312.1270.92
44.50
244.26
119.773.669
0.06 1
0.523
1.721
0.356
0.445
0.792
0.130
0.432
1.167

0.28
0.05
0.08
0.50
0.02
1.55
0.67
0.06
1.42
2.17

86.20
32.77
64.84
83.40
3.27
2.90
4.34

2.345
0.367
3.574
3.703
4.040
2.625
5.677

3.47
0.21
4.08
5.63
0.24
0.15
0.52

Chemical forn
Be2 •
Sc 3+
( ?)
Cy3+
Mn 2 •
Mn 2+
Co 2+
Fe 3+

BW

lW
83Rb

10

--+

I.....

7Se

II..,r ---r

o

10

20

30

T""" (h)

40

so 0

....-

3Rt

...- ...- ~ ;;:;
~

~

I...-

- ,~

W

~

r-tt"'
10

20

30Time (h)

40

SOo

10

ss.j

'1
20

30

40

so

Time (h)Fig. 1. Brain upt ake rates for Se, Mn , Zn and Rb in normal
mice at 6, 12, 24 and 48 hr after ip injection of themultitracer solution.

then freeze-dried. The dried samples were subjected to, -ray spectrometry using pure Ge detectors with reference to an appropriate standard. The uptake behavior
was evaluated in terms of organ uptake rate (the radioactivity percentage of injected dose per gram of theorgan of interest , % dose/g). Data are expressed as
the mean ± SD (standard deviation) for five animals.
Figure 1 compares the brain uptake rates for 54Mn,
65Zn , 75Se and 83Rb tracers in mice at 6, 12, 24 and48 hr after ip injection. The multitracer technique enabled simultaneous tracing of the elements Mn , Se, Zn
and Rb in the identical brain samples and an accuratecomparison of their biobehavior. The results revealthat the brain uptake rate increased with time in 1-,
3- and 8-week-old mice. On the other hand, the uptake
rates for the four tracers in the other organs decreased
with time. Moreover, the uptake rates for all fo ur tracers in the brain of 1-week-old mice were fou nd to bemuch higher than those of 3- and 8-week-old ones. The
uptake rate in the brain of l -week-old mice was in thefollowing order : 83 Rb> 54Mn > 65 Zn > 75Se. However ,in t he case of 3- and 8-week-old mice, the rates werein the following order: 83Rb>65Zn > 54 Mn> 75S e . Thisobserved higher uptake and retention of Mn in younger
mice suggest some active involvement of this element inimportant brain functions during the growth period. 5)

Zn 2+

References

SeO/-

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) S. Ambe et al.: Chem. Lett. 1991 , 149.
3) S. Ambe et al.: Anal. Sci. 7, Suppl., p. 317 (1991).
4) S. Ambe et al.: J. Radioanal. Nucl. Chern. 195, 297(1995).
5) S. Oishi et al.: J. RadioanaJ. Nucl. Chern. 239, 411(1999).

Rb+
Rb+

Sr2 Zr0 2+(?)
Zr0 2+(?)
(?)
Rh 3+

Graduate School of Natural Science and Technology,
Kanazawa University
Faculty of Science, Kanazawa University

RIKEN Accel. Prog. Rep. 33 (2000)

Effect of Oral Administration of N aFeEDTA on
the Biodistribution of Trace Elements
K. Igarashi, Y. Nakanishi, R. Hirunuma, S. Enomoto, and S. Kimura*
Iron deficiency anemia is one of the major micronutrient deficiencies in the world, particulally in developing countries. Recent research has shown an association between iron deficiency anemia and adverse effects on the intelligence quotient in infants and children. One of the method to prevent iron deficiency
anemia in developing countries may be the fortifica~tion of food products with iron. Iron bioavailability
depends on the chemical formula of iron and also theon food component. In developing countries, available foodstuff consists mainly of plant foods. I) The useof NaFe-ethylenediaminetetraacetic acid (EDTA) as afood additive has recently been reviewed by the International Nutritional Anemia Consultative Group andwas strongly recommended as the most suitable iron
fortificant for use in developing countries. However,
EDTA is a chelating agent. 2 ) Thus it may possibly react with other minerals. We considered the influenceof NaFeEDTA on the biodistribution of other trace elements as examined by the multitracer technique. Thisis a part of the previous study of the examination.
As the experimental animal, male wistar rats were
and werepurchased (Charles River Japan, Inc.)
housed in stainless steel cages. The cages were placedin an air-conditioned room and subjected to 12 h oflight. They were fed a standard laboratory diet andhad free access to drinking water prior to the tracer
experiment. A multitracer solution was obtained froman Ag target irradiated by the heavy-ion beam fromthe RIKEN Ring Cyclotron. To elucidate the effect oforal administration of N aFeEDTA on the biodistribution of trace elements, two type of solutions containing ferrous sulfate and N aFeEDTA were prepared. An
equivalent molar solution of EDTA was also prepared
to examine the effect of EDTA itself. Saline was useda control. Finally four groups were arranged. The solutions of ferrous sulfate and NaFeEDTA were orally
administrated to each rat (3 mg Fe/kg B.W.). EDTA
solution and saline was also orally administrated to therats. An amount (0.2 ml) of the multitracer solution
was continuously orally administrated into rats of eachgroup. The rats were sacrificed at 7 hours after administration of the multitracer solution. The radioactivity
levels of their organs were determined by ')'-ray spectrometry.
The uptake of radioactive Fe in organs of the control
rats was the highest among the four groups (Fig. 1).
It is believed that the uptake of radioactive Fe was

1.5

2

1

1.5

,-....
~

0

'-"

cu

1

~

~.o.5
0

Liver

-

0.5
0

Blood

0.4

8

~

0.3

6

(1)

0.2

4

,-....
'-"~

g. 0.12

00SpleenKidney,.-...

o saline

0.09~ 0.06

I1]FS

(1)

~
cd

BaEDTA• NaFeEDTA.... 0.03

g-

o
Brain

Fig. 1. Uptake of Fe in the liver, blood, kidney, spleen andbrain of group I, II, III and control rats.

influenced by presupplied cold Fe such as ferrous sulfate or NaFeEDTA. The uptake of radioactive Fe washigher in organs of group I (ferrous sulfate) than inthose of group II (NaFeEDTA). In addition, the uptake of radioactive Fe in organs of group II (EDTA)
was lower than that in organs of the control group.
The uptakes of radioactive Zn in organs of groups II
and III were lower than those in the organs of control
and group 1. The behavior of Co was similar to that of
Zn. The results in this experiment showed the adverse
effects of NaFeEDTA on the biodistribution of various
elements. Thus , it is difficult to evaluate the effect of
N aFeEDTA in this study. However, this experiment
was carried out using an system of Fe-containing solutions and multitracer solutions in the absence of food ,that is without an inhibitors condition. We require
more experiments to determine the role of the mechanism of NaFeEDTA in the absorption study and thebiodistributions of other minerals.
References
1) L. Davidsson et al.: J. Nutr. 128, 1139 (1998).
2) L. Davidsson et al.: Am. J. Clin. Nutr. 60, 231 (1994).

Graduate School, Showa Women's University

121

RIKEN Accel. Prog. Rep. 33 (2000)

Contribution of Arbuscular Mycorrhizal Hyphae to
Acquisition of Trace Elements by Marigold
H. Suzuki, H. Kumagai ,·l K. Oohashi,·2 and S. Enomoto
The plant roots infected with the arbuscular mycorrhizal fungi (AMF) are known to have higher phosphorus (P) absorption capacities compared to thoseof non-mycorrhizal roots. Difference in this capacity
between mycorrhizal and non-mycorrhizal roots was
based on the increase in P absorption by the arbuscular mycorrhizal hyphae (AMH).l) Similar results are
obtained in experiments involving N, Zn, and Cu. 2) In
the present study, we have examined the absorptionof other trace elements by AMH in the symbiotic system of marigold plants (Tagetes patula L. cv. Bonanza
spray) and AMF (Glomus etunicatum) using a multitracer technique, because the absorption of trace elements by AMH is still rather obscure.
Preparation of a multitracer is described in theliterature. 3,4) A plant container (240 ml pot) was
divided into the "root compartment" (RC) , for thegrowth of the roots and AMH , and the "hyphal compartment" (HC) , for the growth of AMH , by a 20 pm
nylon mesh as shown in Fig. 1. The HC contained
120 g of river sand with a multitracer solution containing the radionuclides of 7Be, 22Na, 46SC , 51Cr,
54Mn , 59Fe, 56Co, 65Zn, 75Se, 83Rb, 85Sr, 88y, 88 Zr ,and 95mTc. The chemical forms of the tracers on application were assumed to be Be2+ , N a +, Sc 3+, Cr 3+,
Mn2+ , Fe3+ , Co 2+ , Zn 2+ , Se032- , Rb+ , Sr 2+, y3+ ,Zr 4+ , and Tc04 - , respectively. 3) The RC was filledwith 280 g of river sand. A marigold seed was sown in
the RC. In the mycorrhizal plant, the spore of Glomus
etunicatum (Becker and Gerdemann) was added to thecenter of the RC. A non-mycorrhizal marigold was usedas the control plant. The plants were grown in thebiotron with a 16/8 hr day/night regime, at 15000 lux,
65% relative humidity, and 25°C. The experiment was
carried out at 35% of the water holding capacity of thegrowth medium. The plants were harvested at 40 and
60 days after sowing (DAS). The radioactivity levelsin the plants were measured with Ge semiconductor
detectors.
Figure 2 shows the relative uptake (% of dose) ofradionuclides in the entire plant. The relative uptakeof 22Na, 65Zn, 75Se, 83Rb, and 85S r in the mycorrhizal
plant was higher than that in the control plant. Although the relative uptake of 54Mn and 88y was lessthan 0.2%, that of 88y in the mycorrhizal plant wasapproximately two times higher than that in the control plant at 60 DAS. In the case of 95mTc, the uptake
in the mycorrhizal plant was similar to that in the control plant. The radioactivities of 7Be, 46S c , 51Cr,59Fe,
•1

*2

122

Radioisotope Research Center, Chiba University
Faculty of Pharmaceutical Sciences, Chiba University

20um nylon
meshFig. 1. The experimental system. RC , root compartment;
HC, hyphal compartment; MT, multitracer.

30~....0 20
**
C1l
Vl

Na

0

**

"C

#.

10
0

C1l
Vl

0

"C

03i:] 15iJJ
Mn

Zn

1

0.2
0.1

0.5

d n

0

d

0

d

ZO'Ii] 15iilj Z'Ia]40

1.4'0 0.7#.

40

60

0OOO6thE 450.g 0.04~ 0.02
Vl

0

40
Y

40

0

60

**

Days after sowing

60

M
Tc

40
0.03
0.02

15

0.01

40

60

Days after sowing

*

0

30

0
60

0.7

40

60

1.4

*

1
0.5

*

40

60

0

60

Cr, Zr, Be,
CO,Sc,Fend nd nd nd

40

60

Days after sowing

Fig. 2. Relative upt ake (% of dose) of trace elements inthe mycorrhizal (black bars) and control plants (whitebars) at two cultivation periods. Each value in the figure represents the mean value ± standard deviation obt ained from four preparations (* P < 0.05 ; ** P < 0.01 ;*** P < 0.001) .

56CO, and 88 Zr could not be detected in any plant.
The results show that AMH can absorb Na, Zn, Se,
Rb , Sr, and Y from the soil and translocate these elements to the plant.
References
1) L. H. Rhodes and J. W. Gerdemann: New Phytol. 75 ,
555 (1975).
2) H. Marschner and B. Dell: in Management of Mycorrhizas in Agriculture, Horticulture and Forestry, editedby A. D. Robson, L. K. Abbott, and N. Malajczuk,(Kluwer Acad. Publ., Dordrecht, 1994), p. 89.
3) RIKEN Rev., No. 13, edited by F. Ambe (1996).
4) H. Suzuki et al.: RIKEN Accel. Prog. Rep. 32, 131(1999).

RIKEN Accel. Prog. Rep. 33 (2000)

Influence of Zn on the Uptake of Various Elements into Carrot
T. Ozaki, Y. Kawamura, and S. Enomoto
To satisfy their growth requirements , plants absorb
cations and anions from their surroundings. The generally accepted theory of ion uptake by plant cells
is that specific molecular carriers transfer the ionsthrough cell membranes which are otherwise almost
impermeable. Zinc is one of the essential elements for
all plants, and it is involved in a number of proteinsand biochemical reactions. 1 ,2) At the same time, toomuch Zn is known to be deleterious to plants. 3 ) Thus,
the effect of Zn on the behavior of other elements merits investigation, particularly for acquiring information
about the interaction between Zn and other elements
around carriers on the surface of cell membranes. In
the present paper, we report the effect of ZnCh on the
uptake of various elements (Be, Na, Mn, Co, Zn, 8e,Rb , Sr, Rh, Ce, Pm, Cd) by carrot, using the multitracer technique developed at RIKEN. 4)
Carrot (Daucas carota cv. U. S. harumakigosun)
seeds were rinsed with distilled water and then allowed to germinate on filter paper. Germinated seeds
were grown on K ureha horticulture soil, and kept ina growth chamber at 23 ± 2°C under supplemental
lighting of 150 /-Lmol·m- 2 ·s- 1 with a 12 h photoperiod. Twenty days after germination, when the lengthof plant bodies and roots was approximately 7 cm, thecarrots were transplanted into ultrapurified water andkept for three days with constant bubbling of air under
the same photoperiod and temperature as above. Justprior to the uptake experiment, all roots were again
washed with ultrapurified water.
An uptake experiment was conducted over two days
with roots of samples maintained in 50 mL ZnChmultitracer solutions (pH 4.5 ± 0.2). After the uptake period, the roots were thoroughly washed with
distilled water and 0.1 mol·L -1 HCI, then wiped withfilter paper. The plant bodies were divided into roots
and upper parts. The uptake ratio for each part was

05

2500

~

2000

~

1500

~
0

~
Cl>

.:::t:.

co

0..

600

(a) Co

T

~

-=0-

0

80
0

200

n
...

..
C\J

0

C\J

8C\J

0

0

0

0
0

0

2000

300

~

500

3000

(b) Rb500
400

I ~.T T1000~

defined as: uptake ratio (%/g)= 100x (radioactivity
in each part/total amount of radioactivity added tothe uptake solution) /fresh weight of the corresponding
part. Each datum point in the figures was given as themean ± standard deviation of five replications.
The portion adsorbed on the surface of roots is considered to be desor bed by washing with 0.1 mol· L -1
HCl. On the other hand , the portion that has permeated the cytoplasm or the unexchangeable fraction in
the so-called apoplast, which is a cell wall continuum inroots where carboxilic groups act as cation exchangers,
cannot be washed out. Based on the above assumption, we discuss the effect of ZnCl 2 on the uptake ofother elements.
The uptake ratios of Co, Rb, and Se for roots areshown in Fig. 1 (a)- (c) . The uptake of Co decreased
with the increase of ZnCl 2 concentration (Fig. 1 (a)).
Two ppm of ZnCl 2 suppressed the uptake of Co to approximately 0.2-fold compared to that in the absenceof ZnCh. To be transported to the cytoplasm via carriers, ions must be adsorbed onto the transport sites of
the carriers in the plasma membrane. Competition between ions with the same electrical charge can thus beexpected. Therefore, the decreases observed in the uptake of Co are suggested to be due to the competition
with Zn for the transport sites of Co.
Interestingly, the uptake of Rb was also suppressedby the addition of ZnCh (Fig. 1 (b)). The decrease
observed in the uptake of Rb+ suggests that Zn2 + has
an affinity for the binding sites of transporting compounds by which Rb+ is transported.
Interactions between anions are also reported, suchas between CI- and N0 3 - or between 80 4 2 - and
M00 4 2 -. In the present study, the concentration of
CI- was also changed, along with the change of Zn2 +concentration. As shown in Fig. 1 (c), however, no influence was observed on the uptake of Se. Considering

80
N

1 ~T
r.:==:-:

1000

1(c) Se

11
T

:::T

100

..

0

0
0
0
0

0

C\J

0

C\J

0
0

0

0

0

0
0

0

C\J

0
0
0

N

0
0
0

0

C\J

0

0

0

0
0

C\J

0

8C\J
0

80
N

Concentration of ZnCI2 (ppm)Fig. 1. Uptake of Co, Rb, and Se into roots.

123

600

--

CJ)

~

~
0

400

~

300

Q)

200

.::t:-

eo
.....
c.

:::J

300

(a) Co

500

100

I
..

100

..

100

j

50

0
0

N

0
N

0
0
N

0

0

0

0

0

N

0
0

0

0
0

(c) Se1::::.. I
..

'7

..

50

a
0

150

I

200

..
..

150

(b) Rb

250

a

a
0

0
0

0

N

0
0

0

0
N
0

0

0

0

0
0
0

0

N

,~

.. ..
0

0

0

N

0

0

0

f
0
N

0

0

T

T

0

!

..
8N

..
80

0

N

Concentration of ZnCI2 (ppm)Fig. 2. Uptake of Co , Rb, and Se into leaves.

the preparation procedure of the multitracer solution,
the chemical form of Se in the multitracer solution isconsidered to be Se032-. The result obtained in thisinvestigation suggests that Se is distinguished from CI
during the uptake into roots , and they are recognized
as different ion species with low physicochemical similarities.
The uptake of Co, Rb , and Se by leaves is shown in
Fig. 2 (a)-(c). Apparent decreases in the uptake byleaves were also observed for N a, Sr, Mn, and Zn withincreasing ZnCh concentration (data not shown). For
the elements which exhibited a decrease in uptake

124

by the leaves, the degree of the decrease was almost
proportional to the decrease in the uptake by the roots.
This indicates that the competition of these elementswith Zn for the binding sites occurred mainly outside
the cytoplasm in the process of entering it, and notinside it.
References
1) B. L. Vallee and D. S. Auld: Biochemistry 29, 5647
(1990).
2) J. E. Coleman: Annu. Rev. Biochem. 61, 897 (1992).
3) G. D. Jessica and M. S. Larry: Soil Sci. 155,376 (1993).
4) S. Ambe et al.: Chern. Lett. 1991 , 149.

RIKEN Accel. Prog. Rep. 33 (2000)

Enhanced Uptake of Mn by LeGlpl-Transgenic Tobacco Plants
M. Takahashi, K. Sasaki,* T. Kitano,* Y. Kawamura, and S. Enomoto
Plants require sources of the inorganic nutrients C,
N, P, and S to synthesize organic cell constituents.
Eleven other inorganic ions have been proven essential for plant growth. Soil is the storehouse of allof these nutrients , except CO 2. Nutrient uptake byplant roots involves an ion-protein interaction in whichtransporter molecules in the root plasma membranerecognize specific ions in the soil solution and absorb
them against a concentration gradient at the expenseof membrane potential, ~pH or ATP.l) It is believedthat the transporter molecule has a site that is essential
for the binding to the ions to be transferred. ABC-typetransporters contain a membrane-peripheral substratebinding subunit.
Metal ions toxic or inadvantageous to plant
metabolism might be inevitably absorbed through thetransporters , mistaken for essential ions with similar
chemical characteristics, such as ionic radius and electronic charge. These ions should be detoxicated byinclusion in stable chelating molecules or by exudation after being absorbed. Metal-protein interaction
may be the most important process involved in metal
homeostasis. Metal-binding proteins may be involved
in individual metal-ion-requiring functions . Transition
metals coordinate with the N in the amino, the S in thethiol, the 0 in the carboxyl and hydroxyl side chains of
the protein molecule. Four to six ligands form an arraywith an interval adequate for forming a metal-binding
pocket. Although some ligands are localized with along interval so that they are distributed over different
strands, some are within the same strand. We developed a screening method for metal-binding proteins,
especially for the membrane protein and the proteinwith metal binding sites unexposed to the solvent. Using this screening method, a metal binding site wasisolated from tomato roots and cDNA was cloned. A
full-length cDNA (LeGlpl) of 828 bp was shown to
encode a precursor protein of 23797 Da having a 27amino-acid leader sequence at the NH2 terminus . The
metal-binding site is located in the NH 2-terminal region of the I97-amino acid-long mature protein, however, the specificity of metals bound to this site is not
yet clear. Tobacco plants (Nicotiana tobaccum SRI)
were transformed with LeGlpl cDNA to express themetal-binding protein in whole tissues. In this study,
the uptake, by LeGlpl-transgenic plants, of the metal
ions in a multitracer was compared with those by nontransformed control plants and GUS (a control gene)transformed plants to identify the metal which predominantly accumulates in the plant expressing the
Department of Applied Biological Chemistry, Osaka Prefecture University

protein with the metal-binding site.
The aforementioned three lines of tabacco plants
were hydroponically grown at 25°C under 18-h-light/6h-dark cycle with Hyponex for two months followed by
distilled water supplemented with a multitracer for 2days. Multitracers were extracted from irradiated Agtargets as described,2) mixed with 59Fe, and subjectedto the growth medium. Plants were further chasedwith Murashige-Skoog's medium for 3 days. With a 1day interval, the radioactivity of Mn, Fe, Co, Zn, and
Rb in the roots and leaves of the subject plants were
determined by a Ge detector (EG & G). Figure 1 shows
the bioaccumulation (% of dose (g of dry wt.)-l) of Mn
in the roots and leaves of the three lines of tobacco
plant. Newly absorbed Mn was transferred to aerial
parts of tobacco plants 3 days after the addition of
54 Mn into the growth medium. Metal-binding LeGlp1expressing transgenic tobacco accumulated most in theleaves of the plants, although the amount of Mn inroots was comparable irrespective of the expression of
LeGlpl. The time course of bioaccumulation of othertransition metals , such as Fe, Co , and Zn, was similar
to that of Mn, with Fe being most rapidly absorbed,
however , the amounts of Fe, Co, and Zn, as well as Rb
did not differ between the three lines of tobacco plants(data not shown).
LeGlpl has a binding site, presumably composed of
two cysteines, for transition metal ions. LeGlpl itself
is localized in tomato roots, not in the leaves. The

20
Gus

LeGlp1

Wild

15
c

0

~

0
0.
0
10
0
c
c

~

Root
5
0-0

o0:d
o

2

4

60

2
4
60
Time, days

2

Fig. 1. Bioaccumulation of Mn in the leaf (open circles)
and root (closed circles) of LeGlpl-transformed (left),
GUS-transformed (middle), and untransformed control(right) tobacco plants.

125

multitracer experiment indicates that accumulation of
Mn in leaves is enhanced in the transgenic plant that
expresses LeGlpl without any tissue specificity, suggesting that Mn is the intrinsic bound metal ion in the
LeGlpl molecule.
References
1) L. V. Kochian: in Micronutrients in Agriculture, 2nd126ed., edited by J . J . Mortvedt, F. R. Cox, L. M. Shuman, and R. M. Welch, (Soil Science Society of America,
Madison, 1991), p . 229 .
2) M. Yanaga, T . Ohyama, M. Iwama, Y. Yoshida, M.
Noguchi, T . Ohmori, R. Hirunuma, and S. Enomoto:
RIKEN Accel. Prog. Rep. 32, 127 (1999).

RIKEN Accel. Prog. Rep. 33 (2000)

Selective Detection of Ee-Decay Radionuclides
in Multitracers: A Proposal
Y. Minai and S. Enomoto
The multitracer technique has been recognized as
an innovative radioanalytical method to study the behavior of trace elements in biological, analytical, andenvironmental systems. Usually, the behavior of eachelement in the system is estimated from its distribution
determined by "(-ray spectrometry. The high resolution of germanium semiconductor detector is responsible for deconvoluting the "(-ray spectrum to obtain the
distribution of the elements applied as multitracers.
Such use of the germanium semiconductor detector
has been very popular in activation analysis for determining trace elements. The high resolution of thedetector changed activation analysis from a monoelemental analytical technique accompanied by tediousradiochemical separation procedures to an instrumental technique for simultaneous determination of multiple elements. Accuracy of instrumental activation
analysis largely depends on the degree of over lap of
the photopeaks from different radionuclides. Careful
examination of each photopeak must be carried out
to avoid overestimation of peak intensity due to theoverlap of the photo peak from another radionuclide.
Such a situation also occurs in the radioassay of themultitracer solution or of systems containing the multitracer. Extremely complex structure of the spectra,
which are sometimes encountered in studies using themultitracer, may influence the accuracy of distribution data on each element. Radiochemical separationof particular group of elements has been applied to reduce the frequency of photopeak overlap in the "(-rayspectra. 1)
As an alternative to the radiochemical methods
for separation of particular elements, detection ofanother radiation from the corresponding radionuclides other than ,,(-rays is proposed. Preparation of
the multitracer at RIKEN starts from production ofradionuclides in the target material by heavy-ion bombardment. Nuclear spallation reaction accompaniedwith bombardment can generate neutron-defficientradionuclides. Those nuclides tend to decay via EC
processes. Utilizing the intense nature of the characteristic X-rays emitted after electron capture, detection of this radiation may be used to evaluate distribution of the EC-decay radionuclides, such as 64Cu,
69mZ n , 109Pd, 107 Cd, and 122Sb.
In earlier studies on use of Si(Li) detectors for neutron activation analysis, great improvement was shownin analytical performance for the determination ofmany EC-decay radionuclides. 2) A relatively simple
structure of the X-ray spectra can reduce ambiguity
in deducing the spectral data. The potential factor
affecting the accuracy of the peak intensity for a particular radioelement with an atomic number Z is the
production of other radionuclides emitting the same
X-ray: ,6-decay radio nuclides with Z-2 and IT-decay
radionuclides with Z-l. As EC-decay involves the ionization of the inner sphere of an electron shell, it was
found that the intensity of the characteristic X-rays ismuch more intense for those nuclides than for the ,6or IT-decay nuclides in analytical condition. 2)
It is noteworthy that the X-ray spectral structure,even as indicated by a simple parameter like the
Ka/K,B ratio, is a function of the oxidation state andthe nature of chemical bonding. 3 ,4) In an application
study, the dissolved species of radionuclides in the multitracer solution are not well recognized. The spectral feature of the emitted X-ray may be a clue in theevaluation of the species in the solution even if theamount of the radionuclide is extremely low relative
to the amounts of nonradioactive components in thesystem.
References
1) S. Arnbe et al.: RIKEN Rev., No. 13, p. 3 (1996).
2) M. Mantel et al.: Anal. Chern. 44, 548 (1972).
3) K. E. Collins et al.: Radiochirn. Acta 28, 7 (1981).
4) Y. Tarnaki et al.: Radiochern. Radioanal. Chern. Lett.
37, 39 (1979).

127

RIKEN Accel. Prog. Rep. 33 (2000)

Evaluation of the in vitro Stability of Radiolabeled DTPA and
DOTA and Their Conjugated Antibodies
Y. Kawamura, S. Enomoto, and R. Amano
In the field of radiopharmaceutical science, radioactive metal ions chelated to small molecules, peptides,
or proteins, such as monoclonal antibodies, have beenused clinically for the diagnosis of cancers and for fundamental studies on the function of various organs. 1)
For example, monoclonal antibodies labeled with radioisotopes such as 67 Ga, 111 In or gOy are used in radioimmunoimaging and radioimmunotherapy. In theselection of suitable isotopes for radiopharmaceuticaluses, we usually compare the in vitro and in vivo
behavior for each labeled compound, which is timework. Moreover, slight changes in the conditions areinevitable in experiments for each radionuclide. With
the multitracer technique, we can obtain much information at one time under identical experimental conditions.
In this work, labeling of antibodies, immunoglobulin G (IgG), with a multitracer was investigated using Diethylenetriamine-pentaacetic acid
(DTPA) and 1,4,7,10-Tetraazacyclododecane-1,4,7,10tetraacetic acid (DOTA) ,2) which is a strong chelating
agent for many metal ions. We attempted to establish a procedure to evaluate the in vitro stability of
the chelate with various metals and the efficiency andselectivity of DTPA and DOTA with metals.
A carrier- and salt-free multitracer solution was prepared from Au foil irradiated with a 135 MeV/nucleon
14 N beam at the RIKEN Ring Cyclotron. Details of
the procedure for multitracer preparation was reported
previously.3) The multitracer solution containing radioisotopes of N a, Sc, Mn, Fe, Co, Zn, Se, Rb, Sr, Rh,
Ag, Ir and lanthanide was evaporated to dryness andthe radioisotopes were dissolved in water.
The efficiency of the radiolabeled chelate was confirmed by paper chromatography (saline), using Whatman No.1 paper strips pretreated with 2.5% albumin.
In the paper-chromatographic system, radio colloids remain at the origin, and the labeled and the free chelate
move with the solvent front.
The spectra of the chromatographed fractions obtained using a high purity germanium gamma (HPGe)
detector were quantitatively analyzed.
The radioisotopes of Zr, Hf, Y and lanthanide were
found to combine with DTPA and DOTA to make stable complexes, while the other radioisotopes, such as
those of the nonmetallic element Se, the alkali metals
Na and Rb and the alkaline earth metal Sr, did not
combine with these ligands. The other metals of Co,
Ga, Mn, Sc also did not form stable complexes.
Conjugation of DTPA cyclic dianhydride to IgG was
performed by the addition of 0.2 ml DTPA cyclic

128

dianhydride in dimethyl sulfoxide (DMSO) solution(5 mg/ml) to 200 ILl of the IgG (ChromPure) solution 11.3 mg/ml containing 0.5 M of NaCI and 0.01 M
of sodium phosphate buffer to ensure a pH of 7.6. After standing at room temperature for 5 min, the mixture was loaded into a Sephadex G-50 (fine) column(of 20 cm height and 1.5 cm I.D.). The column was
eluted with 0.05 M sodium citrate (pH = 5.6). The
fractions showing absorbance at 280 nm (corresponding to IgG-DTPA) were collected. The multitracer solution was added to the IgG-DTPA fraction. After
standing for two hours at room temperature, an IgGDTPA-multitracer fraction was separated from the freemultitracer ions using a molecular cut filter. The radioactivity remaining in the dialysis bag was measured
with a HPGe detector. As a control, the same labelingprocedure was performed with another IgG solution in
the absence of DTPA.
In our experiment, the conjugation efficiency was determined to be 40%. Radioisotopes of Sc, Fe, Co, Zn,
Ag and lanthanide were found to combine with IgGDTPA. The radioisotopes of Se, N a and Rb did not
combine with the conjugating species. Only a small
fraction of the Mn, Rh and Ir radioisotopes combinedwith IgG-DTPA. These results suggest that the stability of the metal DTPA complex was the main factor determining the labeling efficiency. For the control
sample without DTPA, the amounts of radioisotopes
combined with IgG were below the detection limit.
This indicates that once metal ions combine with
IgG-DTPA, the chelate is stable under the conditions
studied. The DTPA and DOTA were recognized as
ligand chelates for particular cations. The conjugatedligands with IgG had an affinity with these cations.
This indicats that steric factors relating to the formation of conjugates with IgG were not a major factor
controlling the affinity with the radioisotopes studied.
These results were confirmed by both ion size chromatography and the adsorption method. This implies
that the simple method applied in this work efficiently
evaluated the efficiency and purity of the labeled compounds. A detailed study of in vitro and in vivo properties of IgG labeling by the multitracer technique isunder way and is expected to provide important information for further radiopharmaceutical studies.
References
1) L. Yuanfang et al.: Pure Appl. Chem. 63,427 (1991).
2) O. A. Gansow et al.: Int. J. Rad. Appl. Instrum. B. 18 ,
369 (1991).
3) S. Ambe et al.: Chem. Lett. 1991, 149.

RIKEN Accel. Prog. Rep. 33 (2000)

HPLC Elution Behavior of Multitracer Metallofullerenes
K. Sueki, K. Akiyama,* H. Nakahara, K. Kikuchi,* S. Ambe, F. Ambe, and S. Enomoto
The formation of metallofullerenes has been reported for the group 2 elements (Ca, Sr and Ba), forthe group 3 elements (Sc , Y and lanthanoids), andfor the group 4 and 5 elements (Zr , Hf and Nb). 1)
In this study, the elution behavior of radiotracer metallofullerenes was examined in two types of stationary
phases for high performance liquid chromatography(HPLC) . A Buckyprep column has a nonpolar stationary phase, but a Buckyclutcher I column has a polar
stationary phase. By combining these two columns ofdifferent characters, it was expected that isomers of
M@C 82 could be identified by their subtle differences
during the retention time.
Crude with multitracer metallofullerenes dissolved
in toluene was passed through a Buckyprep columnof the size i.d.
(Cosmosil, Nacalai Tesque Inc.)
10 mm x 250 mm with a flow rate of 3.2 mLjmin.
Fractions of the eluant were collected every three minutes, and the radioactivity of a specific nuclide in eachfraction was assigned and determined by ,-ray spectrometry using an HPGe detector. In the second ex0.3---e-- 85Sr---0- BBy

0.2----A-- 88Z r

0.1

0.0

.0

0.2

·S

+=
(.)
"::(

0.1

0.0

0.2

0.1

0.0
30

40

50

60

70

Retention time/min

Fig. 1.
HPLC elution curves of multitracer metallofullerenes obtained by ')'-ray measurements. HPLC column: Buckyprep , i.d. 10 mm x 250 mm. Flow rate:
3.2 mL/min. Eluent solvent: toluene.

Retention time/min

Fig. 2. HPLC elution curves of M@CS2 obtained by ')'-raymeasurements. HPLC column: Buckyclutcher I, i.d.
10 mm x 250 mm. Flow rate: 2.0 mL/min. Eluent
solvent: toluene and hexane (7 : 3).

periment, the M@C 82 fractions eluted from the Buckyprep column were submitted to the Buckyclutcher
I column (Regis Chemicals Corp., the size of Ld .
10 mm x 250 mm, a flow rate of 2.0 mLjmin) for
separation with a mixture of toluene and hexane (7: 3) as solvent. Elution was monitored using a UV
on-line monitor, and by ')'-ray off-line measurements ofthe eluted fractions (0.5 min) using an HPGe detector.
The elution curves for an HPLC Buckyprep column
obtained by ]'-ray measurements are summarized inFig. 1 for 85Sr, 88y, 88Z r , 139Ce, 143Pm, 149Eu, 146Gd,
169Yb and 175Hf. The result shows that these curves
can be classified into three groups: group I (85 Sr, 149Eu
and 169Yb), group II (88y, 139Ce, 143Pm and 146Gd) ,and group III (88Z r and 175Hf) .
The elution curves of M@C 82 for an HPLC Buckyclutcher I column obtained by ')'-ray measurements
are summarized in Fig. 2 for 858r, 88y, 139Ce, 143Pm,
146Gd and 169Yb. The result shows that the retention
time at the point of maximum activity depends on theradionuclide detected; being around 20 min for .85 Srand 169Yb, 27 min for 139Ce and 143Pm, and 29 minfor 88y and 146Gd.
These results indicate that the distributions of theradionuclides in the metallofullerene species differ, andthat the retention time of M@C S2 for the second column depends on which radionuclide is examined.
References
1) K. Sueki et al.: Chern. Phys. Lett. 300, 140 (1999).

Graduate School of Science, Tokyo Metropolitan University

129

RIKEN Accel. Prog. Rep. 33 (2000)

Gamma-ray Detection System for Multitracer Research
Y. Yang, Y. Gono, S. Motomura, S. Enomoto, and Y. Yano
Multitracer research is a rapidly developing field
since it improves the reliability and efficiency comparing with those of single-tracer research. Multitracer
in an aqueous solution can be prepared by chemical
separation from a target irradiated by intermediateenergy heavy ion beams. To study the dynamic behavior of nuclides in a sample, their positions in thesample must be measured. Here we propose a detector
system called a Multitracer Gamma Emission Imaging
System (MT-GEI) , which can be used to assign the '"'(rays of different nuclides and measure the positions ofdifferent nuclides without sacrificing the sample.
The proposed detector system consists of two segmented HPGe detector arrays and is shown in Fig. 1.
The '"'(-rays emitted from samples are measured directly
at two consecutive interaction positions Xl and X2 of
two segmented detector arrays. The total '"'(-ray energy is then obtained by adding the energies depositedin two detector arrays once the scattered '"'(-rays havebeen fully absorbed in the second detector array. N uclides can be identified based on the total '"'( energy
because of the very good energy resolution of HPGe
detectors. The Compton scattering angle e is thencalculated from total '"'( energy and '"'( energy loss inthe first detector array using Compton scattering kinematics. Therefore the emission point must lie on thesurface of a cone defined by lines with angle e to thevector XI-X2 through Xl. For a point source, a succession of emissions generates a number of cones whichhave a common point of intersection, thereby defining
the source position.
Monte-Carlo simulations were performed for the
proposed detector system, and a point '"'( source withan energy of 1.332 MeV using the GEANT program. I)
The efficiency of the detector system is defined by the
number of '"'(-rays that undergo Compton scatteringin the first detector array and then are absorbed in
the second detector array divided by the number of'"'(-rays emitted from the source. The detector system
consists of two square arrays, each containing 25
segments of 1 cm x 1 cm x 2 cm. When the sourceis situated in the center of the surface of the firstarray and the distance between the centers of thetwo arrays is 2 cm, the efficiency is estimated tobe 5 x 10- 3 . If the distance from the source to thefirst array and between the two arrays is 10 cm, theefficiency is 3 x 10- 5 . In the Monte-Carlo simulations, the centers of the segments are considered tobe the interaction positions. A three-dimensional
histogram can be obtained by summing a number ofcones generated by a successive emissions of '"'(-rays.

130

Fig. 1. The principle of MT-GEI.

Each cone consists of a number of points that are uniformly distributed on its surface. A one-dimensional
position spectrum in each direction can be obtained
from the projection of the three-dimensional histogramby zooming a region near the source position in theother two directions. The width of the position spectrum decreases as decreasing the size of the segment
and the distance from the source to the first array, andincreasing the distance between the two arrays. The
coordinates of the source position are obtained by fitting the one-dimensional spectra in three directions.
The positional accuracy is defined by the difference
between the actual source position and the source position determined by the simulations. The positional
accuracy is improved by decreasing the width of theposition spectrum and increasing the number of cones
which form the histogram. Simulations were carriedout under the conditions of a 1 cm x 1 cm x 2 cm
segment size in both arrays, and 6 cm distances between both the source and the first detector and thetwo detectors. When the number of cones was 8000, a
positional accuracy of ±0.5 mm in the x and y directions (parallel to the detector array plane) and ± 1 mm
in the z direction was obtained. Further simulations
to optimize the detector system are still ongoing, andbased on the simulations, a detector system will be
developed in the next two years. We are also doing
research to determine '"'( interaction positions with ahigher accuracy than the size of segments using the induced signals in the neighbouring segments. A muchbetter source-position accuracy is expected with thismethod.
References
1) R. Brun et al. : GEANT3 Users' Guide, DD/EE/84-1,
CERN 1987.

RIKEN Accel. Prog. Rep. 33 (2000)

Time Course Induction of p53 in Human Cell Lines
A. Gordon, S. Morimoto, N. Fukunishi, T. Kurobe, T. Mizuno, F. Hanaoka, and F. Yatagai
To assess the influence of mutant p53 gene on mutagenesis, we are characterising the nature of the mutations induced by heavy ions of various LET (Linear Energy Transfer) in the human lymphoblastoid celllines WI-L2-NS (mutant p53) and TK6 (wildtype p53)
which are derived from the same spleen. 1) We are also
monitoring the time course of p53 induction in thesecell lines, and how heavy ions of various LET affectthe cell cycle.
Cell cycle analysis is achieved by the analysis of
DN A content by laser-scanning cytometry of propidium iodide-stained cells at various times after heavyion treatment. At various times after heavy-ion treatment, whole cell extracts are made and used in western blotting analyses using anti-bodies against p53,
p53-phosphorylated at Ser15, p21 and actin. Mutation studies involve the generation and characterisation of hypoxanthine phosphoribosyltransferase gene
(hprt) mutations induced by heavy ions in the two cellline backgrounds.
hprt mutations were induced in TK6 and WI-L2NS cells by irradiation at a LET of 23, 67, and1000 keY / J.Lm for C- , Ne- and Fe-ions, respectively.
WI-L2-NS cells were more radio-resistant than TK6cells after such exposure to these heavy-ions, as they
were to X-ray exposure. hprt mutation induction
under these exposures was also higher in WI-L2-NS
cells. 2 ) Two hours after 3 Gy irradiation (C-ion of
22 keY / J.Lm, Fe-ion of 1000 keY / J.Lm and X-ray irradiation), both p53 and p21 proteins are induced in the
TK6 cell line. However, p53 and p21 are not inducedin the WI-L2-NS cell line after any type of irradiation;
c::

.2

g 0.8

"0

c

.~

0.6

'Q)

ea.

0.4

g? 0.2~~

O~~I""T"""-"-'-''-'-'rT"..,....,.-r-,.....,...''''-''.,.-l

un 0 2 3 4

6

9

12

18

hours after irradiation

Fig. 1. Time course of p53 induction after heavy ion and
X-ray irradiation. The protein was extracted at thetimes indicated after 3 Gy irradiation of 2 x 10 7 cells.
Equal amounts of protein (60 f..Lg) were loaded into eachlane in a 15% SDS-PAGE mini-gel, electrophoresed,and blotted onto a PVDF membrane and probed withmonoclonal antibodies against p53 (DO-I, Santa Cruz
Biotech). X-ray (average of two experiments), diamonds; C-ion (average of two experiments), squares;
Fe-ion (one experiment), circles.

80,---------------,

60
50

40
30
20

10
~

~

~

.r;

o~~~~~~~~~~~

80~---------------~
70

()

as
Q)
.5

60

!!l

50
40 l ......r--o............

~

30

'0

20

1:
~

Oo....--_~~~~~~_

10
O~~~~~~~~~~~

()

8.

80
70

-r--------------------~

I)

80

::~
20~
10

unO

2 34

6

12

18

hours after irradiation

Fig. 2. Cell cycle distribution after heavy ion and X-ray
irradiation. At appropriate times after treatment, cells
were washed with PBS and fixed in 100% ethanol. Propidium iodide and RNase were added and the cells incubated at 37°C for 30 min. Cells were centrifuged and resuspended in PBS and concentrated unto the glass slide
surface by a centrifugation step and then analysed for
DNA content by microscopy. A, X-ray (average of two
experiments); B, C-ion (average of three experiments);
C, Fe-ion (one experiment). G1 phase, diamonds; S
phase, squares; G2 phase, triangles.

in WI-L2-NS p53 is constitutively expressed and p21
is not produced (due to the mutant nature of p53).
The type of irradiation did not alter the p53/p21 response of each cell line as monitored at 2 h. However, the time course of p53 induction appears to bedifferent after the three irradiation treatments, with
X-rays and C-ions producing an earlier maximal levelof p53 induction compared to that induction produced
by Fe-ion irradiation (Fig. 1).3) Cell cycle analysis suggests that X-ray irradiation produces the strongest G2
block, Fe-ion iradiation produces the weakest G2 blockand C-ion irradiation produces a G2 block intermediate between X-rays and Fe-ions. No Gl block was seenin these lymphoblastoid cell lines (Fig. 2).3)
References
1) Y. Kagawa et al.: Mutagenesis 14, 199 (1999).
2) S. Morimoto et al.: submitted for publication.
3) A. Gordon et al.: manuscript in preparation.

131

132

4. Radiation Chemistry and Radiation Biology

RIKEN Accel. Prog. Rep. 33 (2000)

Electron-Hole Plasma Luminescence from the Ion Trackof Insulator Crystals
K. Kimura, S. Sharma, and J. Kaneko
Recently, we found a new extremely fast luminescence band by measuring time-resolved luminescence
spectra (its time resolution of 100 ps) of heavy-ionirradiated a-alumina, and proposed that the origin is
the electron-hole plasma (e-h plasma) or the free exciton complex,1) hereafter, referred to as the e-h plasma.
If this proposal is valid, the corresponding luminescence should be observed not only for alumina but also
for other insulator crystals. We have examined thisfor single crystals of LiF, NaF , NaCI, KCI, KBr, KI,
RbI , CsCI, CsBr, CsI , MgO, Si02, and diamond, andobserved the corresponding luminescence in all crystals except for Si0 2 and diamond. Figure 1 a and b(for KCI) and c and d (for MgO) show decay curves atvarious wavelengths and time-resolved spectra of luminescence, respectively. The luminescence showed thefollowing common characteristics of these samples. (1)The lifetimes were 100 ps or shorter. (2) The band
widths were unusually broad and the wavelength positions were different from all known bands. (3) The
efficiency increased super.linearly with an increase in
the excitation density. (4) The decay rate temperature and the efficiency were almost invariant to temperature changes. These results imply that the originof the luminescence concerned is not self-trapped excitons, free excitons, excited defects, and excited impurity centers which have been reported so far, and alsothat it is not due to a localized excited state but a multiply bound state among short-lived (at most 100 ps)
excited states. The state which suits these characteristics may be the e-h plasma or the free exciton complex, considering that almost all energy deposited byions (as large as a few handled eV / A) is given to electronic systems to produce e-h pairs. The e-h plasma
may decompose stepwise with emissions of photons ofwhich energy is less by binding energy than that of thefree exciton , analogous to excitonic molecules in semiconductors. This is expressed schematically as follows.

KCl/Xeab

6K
xl0**-2
3

MgO/ Xecx10**-2

d

6K
Dns• 0.15ns

x 10:U-2

3

O.4ns

2
1

•

Ins
2.5ns
4ns
500
WAVELENGTH (nm)oa.J!.OUI.O~2.50a::i3.Xi:
O:i:i:4~200
TIME (ns)600

Fig. 1. Figures a and b, decay curves at various wavelengths and time-resolved spectra of luminescence from
KCI irradiated by Xe ion at 6 K; c and d, similar figures
for MgO. The dotted lines represent the peak positionsof the known bands.

hv ==:= Efree exciton -Ebinding -K 2 /4M(==:= 0).

Other emission processes induced by direct electromagnetic interaction between ion beams and substances, e.g., transition radiation, Bremsstrahlung and. Cherenkov radiation, were ruled out by the estimationof luminescence yield and the measurement of light polarization and its spatial pattern.
References
1) K. Kimura, J. Kaneko, S. Sharma, W. Hong, and N.
Itoh: Phys. Rev. B 60, 12626 (1999); K. Kimura, J.
Kaneko, S. Sharma, and N. Itoh: Nucl. Instrum. Methods Phys. Res . B 154, 318 (1999).

n(e-hole) ----t (e-hole)n ----t (e-hole)n_l + hv
n = 1,2, ..

133

RIKEN Accel. Prog. Rep. 33 (2000)

Luminescence Spectra and Decay Curves of Diamond Crystals
Irradiated by Heavy Ions
J. Kaneko, K. Kimura, and S. Sharma
Cathode luminescence analysis is a standard method
for the characterization of diamond crystals, because
it is possible to extract information about band-gap
energy, centers of impurities and vacancies. Synthetic
diamond crystals were irradiated by several kinds ofions from the RIKEN Linear Accelerator for purposes of characterization and study of luminescencecaused by high-density excitation. Luminescence spectra from the synthetic diamond crystals were measured
at 77 K. Time-resolved spectra were measured by using
a single-ion-hitting and single-photon-counting (SISP)
system!) whose time resolution was better than 100 ps.
In this paper, experimental results using heavy ions,
i.e., Xe, were described.
A high-purity type IIa single diamond crystal grownby a high-pressure and high-temperature (HP-HT)
synthesis and a high-purity chemical vapor deposition(CVD) diamond polycrystal were used in this experiment. The type IIa diamond that had almost ideal
crystallinity was estimated to contain less than two
ppm of impurities. The CVD diamond polycrystal
whose grains had a size of several Ilm was estimatedto contain fewer impurities than that of the type Ira
diamond crystal.
In general, a luminescence band, called band A, is
predominant in cathode luminescence spectra of diamond crystals. When the type IIa and the CVD diamond crystals were irradiated by light ions, e.g., He
and Ar, at 77 K , the luminescence spectra had thecenters of band A at 520 2 ) and 360 nm 3 ) respectively.
Figure 1 shows luminescence spectra from the typeIra and CVD diamond crystals irradiated by Xe 27 +at 77 K. There are peaks of free-exciton recombination
luminescence at 235 nm in each spectrum. Sensitivity dependence on wavelength was not calibrated forthese spectra; thus it should be kept in mind that theluminescence yield in the short-wavelength region was
higher than that in long-wavelength region. The luminescence peak located around 520 nm is still predominant in the luminescence spectrum of the type IIa diamond, though there are several peaks at 300 nm thatwere not observed in luminescence caused by light-ion
irradiation. On the other hand, the fine structure ofpeaks around 360 nm became clear in the luminescence
spectrum of the CVD diamond; there are peaks around520 nm that were not observed in luminescence caused
by light-ion irradiation. A peak located at 270 nm is
unique to the luminescence spectrum of the CVD diamond. This peak is probably related to grain boundaries.
Figure 2 shows a time-resolved luminescence spec-

134

(b)
1000

:I~ .
500

N::

! ~.

Wavelength (nm)Fig. 1. Luminescence spectra of (a) HP-HT type IIa and(b) CVD diamond crystals irradiated by Xe 27 + ions at
77 K.

en xlO**-2
=E

4

::J

.0
'-

('tj

---

Fig. 2. Time-resolved spectrum of the CVD diamond crystal irradiated by Xe 27 + at 77 K.

trum up to 4 ns of the CVD diamond crystal irradiatedby Xe 27 +. Although the free-exciton recombination
luminescence was predominant in a time-resolved luminescence spectrum of the CVD diamond irradiatedby Ar 8 +, luminescence peaks around 360 nm became
predominant in the time-resolved spectrum caused by
Xe 27 +. Additionally, there is no peak around 270 nm
in the time range; thus the peak at 270 nm had a slow
decay time.
References
1) K. Kimura and J. Wada: Phys. Rev . B 48,15535 (1993).
2) J. Kaneko and K. Kimura: RIKEN Accel. Prog. Rep .
31, 153 (1998).
3) J. Kaneko and K. Kimura: RIKEN Accel. Prog. Rep .
32, 139 (1999).

RIKEN Accel. Prog. Rep. 33 (2000)

Ultrafast Luminescence and Exciton Dynamics in
Ion-Irradiated RbI Single Crystal
S. Sharma, J. Kaneko, and K. Kimura
We are conducting a study of the luminescence andits decay of ion-irradiated wide-band-gap crystals, using a fast decay measurement technique. Heavy-ion irradiation is a useful method for high-density excitationof such crystals. Our recent studies of ion irradiated Qalumina l ) and alkali halides revealed the formation ofa new 100-ps-lived band. This new finding prompted
us to investigate in detail the luminescence and exciton
dynamics in RbI. Many spectroscopic studies of RbI irradiated with electrons and photons have been carriedout in the recent past. 2 ,3) The three self-trapped exciton (STE) luminescence bands at 320 (0"), 400 (Ex)and 540 nm (1f) have been well identified. RbI appears
to be a unique material in which all the three types of
STE luminescence bands coexist.
The luminescence decay was measured using thesingle-ion-hitting single-photon-counting (SISP) technique with a time resolution of 100 ps.4) The projectile ions He l +, Ar 8 +, Kr l8 +, and Xe 20 + accelerated
by the RILAC were used and the ion energies were
2.0 MeV/nucleon. The time-integrated luminescence

(c)

1.5

0,5

(b)

Wavelength (nm)spectra obtained by ion irradiation, composed of bands
at 320,400, and 540 nm, were similar to those obtainedby electron and photon irradiation. 2 ,3) In contrast, thetime-resolved luminescence spectra showed only the0" band and a new short-lived luminescence component. Figure 1 (a) shows the wavelength-dependent
decay curves obtained by Xe ion irradiation of RbI,
while Fig. 1 (b) shows the time-resolved spectrum. In
these figures , a fast decaying component spread overboth sides of the 320 nm band can be easily noticed.
The half lifetime of this component was estimated to
be about 100 ps, which is the time resolution of ourequipment. The intense band due to the 0" excitons
at 320 nm masks the peak of the 100 ps component,
however the shape of this peak may be similar to thatshown in Fig. 1 (c) which was obtained by subtracting
a suitably enlarged spectrum at 4 ns from the spectrum
at 0 ns.
The excitation density (ED) dependence of the
100 ps component at 400 nm, where the new band isalmost free from the superposition of the 320 nm band,is shown in Fig. 2. It is evident from the equiheight decay curves (Fig. 2 (a)) that the decay rate constant is
scarcely influenced by the ED. This suggests that the
decay rate of the 100 ps component once it is formed,
is no longer influenced by the ED. The luminescence
efficiency however, was largely enhanced with increasing ED (Fig. 2 (b)). The ratio of the efficiencies at t =o (actually in a period of 20 ps) for Ar, Kr, and Xe ion
irradiation was 1 : 7.6 : 53. The intensity by He ion
irradiation was too weak to be evaluated. The intensity ratio for Ar, Kr, and Xe ion irradiation is muchlarger than the corresponding ratio of ED (1 : 1.8 :2.4) and also its square (1 : 3.2 : 5.9), which suggeststhat the 100 ps component originates from multiple
bindings among the primary excited states, i.e., an ex-(b)1

en . 10-3
X

.-g

::l

.ci

~
O:,\;"-"--M.,........-';;';;'~;;\;-"-'Ar~8.....
0.0

.0

4.0

Time (ns)Time (ns)Fig. 1. Luminescence spectra obtained by Xe ion irradiation of RbI at 5 K. (a) 3-D plot of the wavelengthdependent decay curves; (b) time-resolved spectrum;(c) shape of the 100 ps component.

Fig. 2. Ion dependent decay curves of the 100 ps component of RbI measured at 400 nm. (a) Equi- height decay
curves; (b) intensity normalized for the ion count.

135

citon complex. This complex may be formed by thebinding among the electron-hole pairs that are formed
at extremely high densities in the ion track.
The ratio of the luminescence efficiencies of the (Jband (320 nm) for Ar, Kr, and Xe ion irradiation, 1 :
2.1 : 12, is much greater than even the corresponding
ratio of (ED)2, which suggests not only distant radiative interaction between the excited states, but also
stimulated emission.
Further studies related to the exciton reaction in136

wide-band-gap crystals are in progress.
References
1) K . Kimura, J. Kaneko , S. Sharma, W. Hong, and N.
Itoh: Phys. Rev. B 60 , 12626 (1999).
2) K . S. Song and R. T. Williams: in Self-Trapped Excitons, edited by M. Cardona, (Springer, Berlin, 1995),
p. 123.
3) R . T. Williams, H . Liu , G. P. Williams, Jr., and K. J.
Platt: Phys. Rev. Lett. 66, 2140 (1991).
4) K. Kimura and W. Hong: Phys . Rev. B 58 , 6081 (1998).

RIKEN Accel. Prog. Rep. 33 (2000)

Strontium Uptake by Yeast Schizosaccharomyces pombe
Y. Nose and I. Yamaguchi
The disposal of radioactive wastes and nuclear facility accidents are serious social problems. For nuclear
safety assessment, we have been researching the uptakeof various radionuclides by living organisms, particularly yeast. Recently, we demonstrated by using themultitracer technique 1,2) that the yeast Saccharomyces
cerevisiae JCM7255 took up various radionuclides, including strontium-85. Radioactive strontium has been
regarded as one of the most hazardous elements because of its high yields in 23 5U-fission products in nuclear facilities. Therefore, we planned a series of studies viz. (1) the characterization of Sr uptake by yeast
and (2) identification of the genes and proteins related
to Sr uptake. In this article, we report the properties
of Sr uptake by yeast.
In the experiment, the yeast Schizosaccharomyces
pombe was used. The nuclear phase of the strain of S.
pombe was one, whereas that of S. cerevisiae JCM7255
was four. Therefore, S. pombe was considered to be
more suitable for genetic experiments. First, we studied the radionuclides uptake activity of S. pombe. The
yeast was cultured in 10 ml of YEL medium (0.5%(w Iv) Bacto Yeast Extract, 3% (w Iv) glucose) at 25°C,
on a shaker. Cells were collected by centrifugation at
1000 x g, for 5 min. To remove the YEL medium, thecell pellets were suspended in D.W. and recentrifuged
under the same conditions three times. Then, thecells were suspended in 3.5 ml of 10 mM MES buffer(pH 6.0) with 3% glucose. One ml of the cell suspension was transferred into a 1.5-ml tube, and shaken at
25°C. After 30 min, 10 Jll of the multitracer solution
containing 1362.2 Bq of 7Be, 18.6 Bq of 22Na, 95.2 Bqof 46Sc, 313.2 Bq of 54Mn, 83.1 Bq of 56Co, 1063.2 Bq
of 65Z n , 205.5 Bq of 75Se, 3372.8 Bq of 83Rb, 3024.0 Bqof 85 Sr, 1886.4 Bq of 88y, 1318.8 Bq of 88 Zr and 14.1 Bqof 95mTc, was added to the suspension, and which wasthen. incubated at 25°C for 30 min on a shaker. The
cells were collected by centrifugation and washed with
D.W. three times. The cell pellets were subjected to,-ray measurement and protein assay. Table 1 showsthat the yeast S. pombe had the ability to take up various radionuclides, including 858r. In the next step,a single tracer, 85SrCl, was used instead of the multitracer solution. The yeast cells were cultured in 1.5 ml
of YEL medium, and washed and collected in the samemanner described above. The cells were suspended in
1.5 ml of 10 mM MES buffer (pH 6.0) with or without
3% glucose, and shaken at 25°C. After 30 min, 85SrCI
was added, and the cells were incubated at 25°C for
30 min. Then the cells were washed, collected and subjected to ,-ray measurement and protein assay by thesame procedure described above. Figure 1 shows that

Table 1. Uptake of various radionuclides by Schizosaccharomyces pombe. Data represent the the 'Y-ray activity(Bq) of each radionuclide per microgram of cell protein.
N.D. : not detectable.
NuclidesBq/ /.i. g protein (X 10 -I)
Ave.
±
SD

Be- 7
Na- 22Sc- 46
Mn-54
Co- 56Zn- 65Se-75
Rb-83
Sr- 85
Y - 88Zr- 88
Tc- 95m

4.32
N.D.
0.04
2.93
0.70
9.13
0.11
21.04
8.75
8.25
0.27
N.D.

0.46
0.01
0.29
0.09
0.92
0.02
2.27
1.02
1.02
0.08

12000
10000

.~
8Po. 8000
Oll

i
~

6000
4000
2000

3% glucose

+ -

+ -

Initial cone. of
SSSrCI2 (J). M)

0.1

0.5

+ -

+ -

Fig. 1. 85Sr uptake by Schizosaccharomyces pombe. Data
represent the 'Y-ray activity (cpm) per milligram of cell
protein.

the amount of 85Sr taken up by S. pombe in the buffer
with glucose (+glucose) was significantly larger thanthat in the buffer without it (- glucose). In +glucose,
the amount of 85Sr taken up increased depending on
the amount of 85Sr added to the cell suspension. However, in -glucose, the amount taken up remained at alow level over the entire 85Sr concentration range examined (0.5- 2 11M).
To identify the gene(s) related to the Sr uptake, weare planning to produce transformants of S. pombe by
restriction-enzyme-mediated integration (REMI). The
transformants will be tested for the Sr uptake, in order
to select the cells with low or high Sr uptake ability.
The genes disrupted by REMI event will be identified;
and further more, the uptake of various metals by thetransformants will be studied by the multitracer technique.
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).

137

RIKEN Accel. Prog. Rep. 33 (2000)

Influence of Endophytes on the Uptake of Radionuclides
by Perennial Ryegrass
T. Soshi, T. Arie, Y. Nose, and 1. Yamaguchi
Radionuclides released by nuclear power plants into
the environment are a potential risk to human health.
Consumption of food contaminated with radionuclides,
due to their transfer from soil to plants and then to
livestock, is a significant pathway for human exposure
to radionuclides. To decrease such exposure doses ofhumans , it is desired to eliminate radionuclides fromthe soil. Phytoremediation is a good method to remove radionuclides from the soil. We have shown thatseveral factors influence the uptake of radionuclides byplants, including soil profile, pH and microorganisms
in the soil. 1 ,2) But the influence of microorganisms on
the uptake of radionuclides by plants remain unclear.
Endophytes are fungi that live inside grass, for example, in tall fescue (Festuca arundinacea) and perennial ryegrass (Lolium perenne). The relationship between grasses and endophytes is symbiotic. The endophytes do not harm the grasses , but they sometimes
produce toxins that are harmful to livestock. 3) Infected
plants can grow better and show higher drought tolerance and resistance to insects than noninfected ones.
In this paper, we report the influence of an endophyteon the uptake of radionuclides by perennial ryegrassusing a multitracer.
Genetically identical strains of perennial ryegrassthat were infected with an endophyte (Neotyphodium
lolii) and noninfected strains were kindly supplied by
Dr. Shimanuki (National Grassland Research Institute,
MAFF , Tochigi). Five plants were used in each treatment , and grasses were grown in five plastic pots containing 150 g of sterilized horticulture soil (K ureha engei baido , Kureha Chemical Industry Co. Tokyo). A
solution of diluted multitracer and radioactive cesium
was administered to each pot. The same amounts ofsolution were absorbed by filter paper for comparison.
Plants were cultivated in a green house at 25-30°C andunder 15000 to 17000 lux light for 12 hrs a day. After
4 weeks, aerial parts of plants were collected and driedat 50°C. Then the radioactivity was measured using
hyper pure Ge detector and the results were expressedas the uptake percentage compared to the control pergram dry weight of the plant.
Figures 1 and 2 show the uptake rate of several
elements (Sc, Mn, Co, Zn, Se, Rb, Sr, Cs in Fig. 1, Na
and Tc in Fig. 2). In the noninfected strain, the uptake

138

0 : Endophyte . : Endophyte +

o
Mn

Sc

Co

Zn

Se
Element

Sr

Rb

Cs

Fig. 1. Influence of endophyte presence on the uptake rateof eight elements by perennial ryegrass.
50

~

40

tIC

30

0 : Endophyte . : Endophyte +

~
0

"-

~
Q)

+J

~

20

Q)

x
~

a.
:::>

10

0

Tc

Na

Element

Fig. 2. Influence of endophyte presence on the uptake rateof Na and Tc by perennial ryegrass.
rates of Na and Tc were high, about 10% for Na and
32% for Tc. For other nuclides , such as Sc, Mn, Co, Se,
Rb and Sr, the uptake rates were relatively low (1 % to8%). The uptake rate of Cs and Zn was less than 1 %(0.14 % Cs and 0.77% Zn). In the endophyte infectedstrain, almost all of the element's uptake rates werereduced.
References
1) S. Gouthu et al.: RIKEN Accel. Prog. Rep. 30, 117(1997).
2) S. Gouthu et al.: RIKEN Accel. Prog. Rep. 31, 146(1998).
3) M. R. Seigel et al.: Ann. Rev. Phytopathol. 25, 293(1987).

Analysis of Heavy-Ion Beam-Induced DNA Damage in
Saccharomyces cerevisiae
M. Yoshimasu, T. Abe, S. Yoshida, F. Ling, and T. Shibata
It has been reported that a heavy-ion beam induced
DN A double-strand breaks in the diploid cells of Saccharomyces cerevisiae and caused both point mutations and deletions of genomic DNA in a human cellline. 1 ,2) In this study, we reported that the nuclear
mutations were induced in the haploid cells of S. cerevisiae by accelerated heavy-ion beam irradiation. To
identify these mutations, the sequence alternations inan open reading frame (ORF) of the URA3 gene were
examined.
We used the haploid cells ofIL166-187 (a, leu2, trpl,[p+])3) to induce the damage by a heavy-ion beam into
the genomes. The cells, grown in a glucose medium at
30°C for 3 days were spread on 1% agar plates without the amino acids required for cellular growth. The
plates were exposed to irradiation with 5 to 200 Gyof the 2oNe-ion beam (135 MeV lu) accelerated by the
RIKEN Ring Cyclotron. The linear energy transferof the 2oNe-ion corresponded to 63.4 ke VI j.Lm. Afterthe irradiation, the cells were suspended in sterilized
water and then spread on glucose plates. After incubation at 30°C for 4 days, the survival rates at various
doses of the 2oNe-ion beam were calculated. 4 ) Then,the cells irradiated at 50 Gy with 32% of survival rate
were spread on 5-fiuoroorotic acid (FOA) containing
plates to select the cells required for uracil (ura-). After that, the whole cellular genomes were purified fromthe ura- cells and used for amplification of the ORF of
the URA3 gene by PCR. The PCR products were digested by Apa I and the sizes of the PCR products werecompared with that of the URA3 gene amplified fromwild-type cells through acrylamide gel electrophoresis.
As shown in Fig. 1, all PCR-amplified DNA fragmentsfrom 20 mutant clones had the same length. Since it
has been reported that heavy-ion beams caused deletions of genomic DNA with eighty base pairs in animalcells,2) if any deletions occurred, different sizes of PCR
products would be observed. Finally, we examined thesequences of the PCR-amplified ura3 gene in 6 clones(Table 1). Among the sequenced fragments, only point
mutations with base transition from C to T or G to A
were detected.
The heavy-ion beam induced DNA deletions inanimal and plant cells, but we could not detect deletions on the genomes in our experiment. It is likelythat there are different cellular systems corresponding
to the biological effects of a heavy-ion beam on the

500 400-

8bp..... 524bp

500 400..... 438bp

Fig. 1. Electrophoresis in acrylamide gel of DNA fragmentsof the ura3 gene mutated by the heavy-ion beam.
Table 1. Ne-ion beam-induced point mutations.
Clone
number4

Mutation
point

Transition ofbases

Replacement ofamino acids

ura3-134

403 C~T

134 Gln~stopura3-202

608 C~T

202 Pro~Leu

ura3-203

611 G~A

203 Giy~Asp

genomes between yeast and animal or plant cells.
References
1) S. Ikpeme et al.: Radiat. Environ. Biophys. 34, 95(1995).
2) Y. Kagawa et al.: J. Radiat. Res. 36, 185 (1995).
3) F. Ling et al.: EMBO J. 14,4090 (1995).
4) M . Yoshimasu et al.: RIKEN Accel. Prog. Rep. 32, 148(1999).

139

RIKEN Accel. Prog. Rep. 33 (2000)

Effective Plant-Mutation Method Using Heavy-Ion Beams (IV)
T. Abe, M. Miyagai, and S. YoshidaIn the previous paper 1 ) we have reported that tobacco is quite sensitive to the irradiation with heavyion beams during the stage of fertilization. However,
it is difficult to apply this method at this particular
stage for plants that have several seeds per flower. In
this paper we report the effect of heavy-ion beams on
dry seeds, imbibition seeds and calli of tobacco.
Tobacco seeds (Nicotiana tabacum cv. Xanthi and
BY-4) were incubated in 1/2MS agar medium for
24 hrs before irradiation. The imbibition seeds anddry seeds were irradiated with N or Ne-ion beams(135 MeV /u) within a dose range of 5 to 200 Gy. The
linear energy transfer of the Nand Ne ion corresponded
to 30 and 63 ke V / J,lm, respectively. One month after
the irradiation, we determined their germination percentage, growth rate and morphological abnormalities.
Calli (BY-4) were irradiated with N or Ne-ion beams(135 MeV /u) within a dose range of 5 to 50 Gy. After
irradiation, calli were cultured on MS medium containing 1mg/L 2,4-D at 25°C under continuous light. Callus growth was measured after two weeks. The growthrate was calculated by dividing the increment in the
fresh weight by the initial weight.
The germination and survival rates were not affectedby ion beam irradiation in the case of dry seeds (Table 1). In the case of imbibition seeds, the germination
rate was reduced when irradiated at 100 and 200 Gy,
and the germinated plants produced no leaves and diedat doses higher than 20 Gy (Fig. 1). The irradiation of
Table 1. Effect of heavy-ion beams on seed germination.
Germination (%)
XanthiIon

Gray

Control 0
N

5

10
20
50
100
200
Ne

5

10
20
50
100
200

140

Dry
98.8
98.7
98.9
97.2
99.5
98.6
98.8
99.6
100.0
98.8
99.6
99.6
99.2

BY-4

125
100

~
~

"C

75

.s..<::
~

8

50

~

25

Dose (Gy)Fig. 1. Effects of irradiation of imbibition seeds with Ne-ion
beams on the growth rate. 0: Xanthi and .: BY-4.

4~------------------~

3

10

100

Dose (Gy)Fig. 2. Effects of irradiation of the callus with ion beams
on growth. 0: N ion and .: Ne ion.
dry seeds with N ions resulted in variegation in Xanthi (1 plant/1239 germinated plants) and formation ofpale green leaves in one plant of BY-4 (1/1010) of the
Ml progeny. The frequencies of morphologically abnormal plants, obtained following N-ion irradiation ofembryos during fertilization cycle, were 18.1 and 0.82%
for Xanthi and BY-4, respectively,2) whereas the frequencies were 0.08% for Xanthi and 0.1% for BY-4 ofdry seeds. Callus growth was inhibited at doses higher
than 10 Gy (Fig. 2). The results indicate that there isa difference in sensitivity to ion beams between organsof tobacco. The sensitivity of these organs decreased in
the following order: calli, ' embryos during fertilization
cycle, imbibition seeds, dry seeds.

Imbibition

97.4

Dry
99.0
98.4
97.2
96.3
98.8
100.0
98.8
100.0
100.0
99.6

98.5

References

97.9

99.4

95.6

97.1

100.0

75.9

ND

99.5

ND

1) T. Abe et al. : in Modification of Gene Expression andNon-Mendelian Inheritance, edited by K. Oono and F.
Takaiwa, (NIAR, 1995), p. 469.
2) T. Abe et al.: RIKEN Accel. Prog. Rep. 30, 127 (1997).

Imbibition
98.8
96.9
95.6
94.7
96.0
93.8
73.6
93.3
96.9

99.0
91.7
97.5
98.0
98.2
38.7
7.7
99.0
98.3

RIKEN Accel. Prog. Rep. 33 (2000)

Effects of Heavy-ion Beam Irradiation on Shoot Elongation in Roses
T. Kitaura, Y. Hara, T. Abe, K. Miyoshi, and S. Yoshida
Breeding programs of roses through conventionalcrossing methods have proven difficult for its genetic
improvement due to the variation in ploidy levels, highsterility and genetic heterozeigosity. The spontaneous
as well as artificial mutations in a crop, which can beeasily propagated vegetatively, will accelerate its genetic improvement. Mutants of rose have been successfully induced yielding alteration of growth habitat
and flower color by treatment with chemical mutagen
and radiation. Heavy-ion beam irradiation, which isconsidered to result in new variations in phenotype of
induced mutants, has recently been reported as an alternative method of inducing mutation in some crops.
The objective in the present study is to determine theeffect of heavy-ion beam irradiation with 20Ne and 14N
on rose mutation breeding, particularly the effect of
exposure dose on shoot elongation of spray type roses.
Two spray type rose cultivars, namely 'Love me tender' (pink flower) and 'Bridal Fantasy' (white flower)
were used. Ten offshoots (ca. 70 mm long) were used
for each treatment. The explant contained one winter bud. Irradiation treatments were conducted in thedose range of 5, 10, 20, and 50 Gy for 20Ne ions and 5,
10, 20, 50, and 100 Gy for 14N ions with control (0 Gy)
at an energy of 135 MeV lu. The buds were grafted on
the rose stock one day after irradiation. Survival of
bud and length of shoots from the grafted bud wererecorded one and two months after grafting, respectively.
Survival rates of buds and length of shoots decreased with the increase in exposure dose. Survival
rates and shoot length were lower after 20Ne beamtreatment than that of 14N of the same exposure dose.
No clear-cut genotypic difference was found in the
response to irradiation. The values of LD so for thetwo varieties were found to be 10-20 Gy of the 20Ne
ion and 20-50 Gy of the 14N ion, respectively (Tables 1

Table 1. Effect of 20Ne heavy-ion beam irradiation on
growth of roses.
Cultivar
Love me tender

Bridal fantasy

Dose
(Gy)
0
5
10
20
50
0
5

10
20
50

No. plants

Survival
(%)

10
10
10
10
10
10
10
10
10
10

90
80
80
50
10
100
70

50
50
0

Shoot length
(em)
24.9
24.1
20.5
1.9
0.0
46.4
9.1
12.6
1.1
0.0

Table 2. Effect of 14N heavy-ion beam irradiation ,o ngrowth of roses.
Dose No. plants Survival Shoot length
(em)
(Gy)
(%)
24.9
Love me tender
0
10
90
34.2
5
10
100
10
22.5
10
90
20
10
90
35.6
50
9
56
0.6
100
10
30
0.0
Bridal fantasy
46.4
0
10
100
100
39.5
5
10
22.3
100
10
10
36.6
20
10
100
50
10
40
0.4
44
0.0
100
9
Cultivarand 2). Some chimeric tissues, such as the red sector
in the petals of the pink flower, from irradiated buds
were observed. Further experiments to induce moreshoots from the putatively mutated sections should be
conducted to obtain the mutants of roses.

141

RIKEN Accel. Prog. Rep . 33 (2000)

Adaptive Response of Human Cultured Cells to
Heavy-ion Irradiation
S. Morimoto, A. Gordon, N. Fukunishi, T. Kurobe, F. Hanaoka, and F. Yatagai(1000 ke V / J.Lm) . The cells were then challenged by
X-ray irradiation and the survival, mutation induction
and protein induction were determined (Fig. 1). Under

Cells can become resistant to cytotoxic treatment after a low-dose exposure to various physical and chemical agents. This phenomenon is observed not only inprokaryotic cells but also in fish, plant and mammaliancells, and is defined as adaptive response. The basic
mechanism of this adaptive response is not yet wellunderstood but is regarded as an important index toestimate the risk of low-dose radiation.
The reaction kinetics of the radioadaptive response
to low-dose X-ray exposure have been studied in quiescent cultured mouse cells. 1) Mouse m5S cells preexposed in the G1 phase to low doses of X-rays became
insensitive to the induction of chromosomal aberrations, mutations causing 6-thioguanine resistance andcell killing. 2) In this study, we focused on such a response to heavy-ions since this subject has not beenthoroughly studied.
Human lymphoblastoid TK6 cells were incubated for 2 hours at 37°C after pre-exposure to
5, 10 or 20 cGy of C-ions (22 keY / J.Lm) or Fe-ions

pre-irr1ati~n.......

o2hincubation time

4h..
Survival
assay
Mutationassay

Fig. 1. Time schedule of the survival, mut ation and protein
assays. After 5, 10 and 20 cGy X-rays, 22 ke V / p,m Cion and 1000 keY / p,m Fe-ion pre-irradiation , cells wereincubated for 2 hours at 37°C in 5% CO 2 and thenchallenged with X-rays.

Fe-ion (1 OOOkeV/~m)

C-ion (22keVI~m)

X-ray

X.-r...................... .

c

o
.j..J

u

~

0.1

LJ..

~

OcGy
ScGy
- 0'. 10cGy--0·· 20cGy

O'l
C

>

~

OcGy
ScGy
- 0'. 10cGy--0-· 20cGy

-n.

0.01

.~

:J

-n.

t/')

2
Dose (Gy)

3 0

1

2

3 0

Dose (Gy)12Dose (Gy)3

Fig. 2. Survival curves against X-ray dose after 5, 10, and 20 cGy X-rays , 22 keY / p,m C-ion and1000 keY / p,m Fe-ion pre-irradiation.

~

~
~

rr

( xl 0 '5)( X 1 0 .5 )4 i----~------------~(

X 1 0 .5 ),------------------,

X-ray
C-ion (22keV/iJm) Fe-ion (lOOOkeV/IJm)
3 ~4----4----------~~~______~~____~ r-----------------~

Q)
~

u.

c

2

o

.~

ctI

~

~

~

0

Fig. 3. Hprt mutation frequency after exposure to 1 Gy X-rays. 2 hours before the challenge, cells werepre-irradiated by 5 cGy X-rays, 22 ke V / p,m C-ions and 1000 ke V / p,m Fe-ions. There are no standard
error bars for Fe-ions due to the results of a single experiment.

142

(a)
+-'

(1 ) pre-X-ray(2) pre-C-ion(3) pre-Fe-ion

pre +pre pre +pre pre +3 ,...:..-_ _ _-.:.1. . ;1_ _ _----...:.. .-----1-1-------, .---_ _ _ _1_1_ _ _---.
pre -

c

::J

~ 2

«
(l)

>

'+:i

ro

Q)
0::::

(b)
+-'

c

0'---

o

pre -

2

o

2

pre +

020

pre +

pre -

o

2

o

2

o

2

o

2

pre +

pre -

I I

3

::J

~ 2

«

(l)

>

'+:i

C'\I

Q)
0::::

(c)
+-'

c

0

o

2

o

2

o

2

o

2

pre +

pre -

pre +

pre -

pre +

pre I I

3

::J

~ 2

«

(l)

>

'+:i
C'\I

Q)
0::::

0 1......1_.----'

o

2

o

Challenge dose (Gy)

2

o

2

0

2

Challenge dose (Gy)

o

2

0

2

Challenge dose (Gy)Fig. 4. Western blot analysis of (a) p53 , (b) p53-Ser15-P and (c) p21 protein induction after 2 Gy X-ray
irradiation with and without 5 cGy pre-irradiation. The same amount of protein was loaded in eachlane and the blots were probed with DO-1 (Santa Cruz Biotechnology), Ab-1 (Oncogene Research
Products) and phospho-p53 antibody (BioLabs) . The amouts of protein were corrected using actin
and the amount of protein induced after 2 Gy X-ray irradiation with no pre-irradiation was arbitrarily
set to a value of 1.

the present condition of pre-irradiation and subsequent
radiation treatment , the cells did not acquire any significant radioresistance (Fig. 2). Similarly almost no
reduction in hprt mutation induction was observed following these heavy-ion irradiations (Fig. 3). To determine the survival fraction and the mutation frequency,
we followed the procedure described by Kagawa et al. 3 )Since such an adaptive response was not clearly detected even with pre-X-ray irradiation (Figs. 2 and 3),
we would like to consider the possibility that this lymphoblastoid cell line exhibits poor adaptive responses,
unlike the aforementioned mouse cells. Consistent withthese results, the induction patterns of p53 , p53-ser15phosphorylated and p21 were similar between the
X-ray- and the heavy-ion-irradiated groups (Fig. 4).
Here, we would like to emphasize the relatively
high level of induction of the above protein following

exposure to a very small dose of 5 cGy for all tested
types of radiation. It is thus important to study thecellular responses to low-dose radiation, including thatto heavy-ions. FUrthermore, the adaptive responsemust be evaluated not only in terms of the survival
and mutation rate but also in terms of the characteristics of the mutations. Toward this end, we are now
analyzing the induction of the TK mutation using thesame cell line. FUrthermore, we plan to use a fibroblast
cell line to carry out a similar study.
References
1) M . Sasaki: Int. J. Radiat. BioI. 68, 281 (1995).
2) M. Sasaki : Radiation Biology Center of Kyoto University, personal communication.
3) Y. Kagawa, T. Shimazu, A. J . Gordon, N. Fukunishi, N .
Inabe , M. Suzuki, M . Hirano , T. Kato, M. Watanabe , F .
Hanaoka, and F. Yatagai: Mutagenesis 14, 199 (1999) .

143

RIKEN Accel. Prog. Rep. 33 (2000)

Cytogenetic Effects of Heavy-Ion Beams on Mammalian Cells
N. Shigematsu,* S. Yamashita,* N. Ihara,* T. Kawata,* O. Kawaguchi,* A. Kubo,*
H. Ito, * T. Kanai, Y. Furusawa, and F. Yatagai
Previous studies have shown that heavy particles
are more lethal to mammalian cells than sparsely ionizing radiation such as , or X-rays.1- 5) Induction of
mutations by high-LET ions was investigated in rodent and human cells using the well-known HPRTlocus and TK-Iocus models, and the results revealed
higher levels of mutation than that induced by lowLET radiation. 3-5) Transformations caused by heavy
ions are dose- and LET-dependent and are more frequent than those induced by X-rays. It has also beenshown that high-LET particles induce high rates of
DNA strand breaks and chromosomal breakage andrearrangement. 6-9) Chromosomal rearrangements induced by sparsely ionizing radiations are well known,and cytogenetic analyses of irradiated human lymphocytes have been widely applied to biological dosimetry.
However , much less is known about chromosome aberrations induced by high-LET particles.
Most of the studies on chromosomal aberrations induced by heavy-ion radiation reported thus far havebeen performed using Giemsa-stained or R-bandedchromosomes and have dealt with dicentric, fragment and ring formation as indicators of chromosomalchanges. However , other types of aberrations such astranslocations and insertions cannot be detected using
these techniques. Chromosome staining by the FISH
technique will facilitate simple and accurate analysis,
particularly of translocations in metaphase chromosomes.
To investigate (1) whether the energized-charged
particles have a more efficient effect than sparsely ionizing radiations in inducing chromosomal aberrations,(2) whether the chromosomal aberrations is dose- andLET-dependent, and (3) whether the different effects
are observed in different types of particles as we showedby HPRT-Iocus mutations caused by carbon and neon

Department of Radiology,
Medicine
144

Keio University School ofparticles used at the same LET level,3- 5) we will carryout the experiment with the following plan.
The cultured cell samples and blood samples collected from human donors are irradiated at room temperature. Heavy-ion irradiation will be performedin the plateau region of the Bragg curve with various shielding, using carbon, neon and argon. One
to three hours after irradiation (samples on on ice in
the interim) , the samples will be distributed in culture
tubes , and cells in metaphase will be harvested after acolchicine block to score chromosome aberrations using the FISH technique with chromosome #1 and #2
paint probes.
References
1) E . A. Blkely, F. Q . H. Ngo, S. B. Curtis , and C. A.
Tobias: Adv . Rad . BioI. 10, 191 (1983).
2) P. L. Petti and A. J. Lennox: Ann. Rev. Nucl. Part Sci .
44, 155 (1994).
3) K . Toya, N. Shigematsu, H . Ito, S. Yamashita, A. Kubo,
and T . Kanai: Nippon Acta Radiol. 56, 736 (1996).
4) T. Kawada, N. Shigematsu, H. Ito, S. Yamashita, K.
Toya, A. T . Yida-Sakate, A . Kubo, and T. Kanai:
RIKEN Accel. Prog. Rep. 30, 134 (1997) .
5) T. Kawada, N. Shigematsu, H. Ito, S. Yamashita, A.
Takeda, K. Toya, R . Ishibashi, A. Kubo, T . Kanai, Y.
Furusawa, and F. Yatagai: RIKEN Accel. Prog. Rep.
31 , 149 (1998).
6) R. Roots, W . Holley, A. Chatterjee, M. Irizarry, and G.
Kraft: Int. J . Radiat. BioI. 58 , 55 (1990).
7) J. A. Stanton, G. Taucher-Scholz, M. Schneider, J.
Heilmann, and G . Kraft: Radiat. Environ. Biophys. 32,
21 (1993).
8) G . Taucher-Scholz, J. A. Stanton, M. Schneider, and G.
Kraft: Adv. Space Res. 12, 73 (1992).
9) T. Kanai, Y. Furusawa, K. Fukutsu, H. Itsukaichi, K .
Eguchi-Kasai, and H . Ohara: Radiat. Res. 147, 78(1997).

RIKEN Accel. Prog. Rep. 33 (2000)

Effect of Heavy Ion Beams on Cell Cycle Progression
K. Eguchi-Kasai, H. Itsukaichi, M. Murakami, T. Kanai, and F. Yatagai
The analysis of chromosome aberration is an effective method to estimate the radiation dose during aspace mission or at an accident at an atomic power
station. Since mitotic delay is dependent on radiationdose and radiation quality, it is important to study cell
cycle disturbance after irradiation with various typesof radiations and at various doses using different typesof cells. We studied the cell cycle progression in normal
human fibroblasts (NBIRGB) or rodent cells (V79) after irradiation with carbon-ion beams.
The cells were irradiated with carbon-ion beams
from the Ring Cyclotron at RIKEN, the Heavy Ion
Medical Accelerator in Chiba (HIMAC) and the Cyclotron Facility at NIRS. Initial accelerated energies ofcarbon ions were 135 MeV I nucleon at RIKEN, 135 and
290 MeV Inucleon at the HIMAC and 12 MeV I nucleon
at the Cyclotron Facility. Linear energy transfer(LET) of the beams on the target was changed byinserting a plastic plate in front of the target. The
LET range was 30- 250 keY I J.Lm at the sample center.
The radiation dose rate ranged from about 1-5 Gy 1m.
The reference radiation was 200 kVp X-rays filteredthrough 0.5 mm Al and 0.5 mm Cu with a dose rateof 0.9 Gy 1m. After irradiation, the cells were incubated with 5 J.LM bromodeoxyuridine (BrdU) if necessary, and the cells were then trypsinized and fixedwith 70% ethanol. The cells were stained both withpropidiumiodide to measure the total DNA contents ina cell and anti-BrdU-fluorescein for the newly synthesized DNA, and analyzed with a flow cytometer. Cell
cycle distribution was analyzed using the ModiFit LT(Becton Dickinson).
For the asynchronous V79, more than 80% of thecells were in the G2/M phase from 4 to 12 h after
irradiation, with a peak at around 6 h. The maximum
value and the width of the peak increased with bothincreasing LET and radiation dose. The relative biological effectiveness (RBE) of G2 arrest was calculatedusing the width of the peak at the half values. RBE increased with LET up to 180 keY I /-lm. RBE values forG 2 arrest above 30 ke VI J.Lm were greater than those forthe cell inactivation in which the RBE-LET curve hada peak around the LET of about 100 keY I /-lm. Moreprecise analyses were carried out using BrdU. Because
the cells were continuously labeled with BrdU after irradiation, cells in the G 1 and the S phases at the timeof irradiation incorporated BrdU. Labeled cells exhibited G 2 arrest from 6 to 16 h after irradiation, depending on LET and radiation dose. In contrast, unlabeledcells exibited little G2 arrest. Therefore, the high percentage of V79 cells exhibiting G2 arrest was due tothe populations in the Gland the S phases at thetime of irradiation. There was no G 1 arrest for V79
cells. This is natural because p53 gene of the V79 cells
was mutated in a presumed DNA binding domain. I ) In
contrast, there was a high percentage of NB1RGB cells
exhibiting G 1 arrest, and a low percentage of those exhibiting G2/M arrest; these cells have the normal p53
gene. 2)In our first experiment of cell cycle analysis of V79
cells at the RIKEN Ring Cyclotron, a low percentage
of cells in the G2/M phase was observed after 8 h incubation following the C-ion irradiation with LET of
153 keY l/-lm. The cells may have been synchronized
during the time they were transported from NIRS to
RIKEN . More carefully prepared samples are necessary.
References
1) W. Chaung et al.: Nucl. Acids Res. 25, 992 (1997).
2) K. Tsuboi et al.: Int. J. Radiat. BioI. 74, 71 (1998).

145

RIKEN Accel. Prog. Rep. 33 (2000)

Recognition of Hit Sites within the Cells Exposed to
Accelerated Iron Ions Using CR-39 Plastics
H. Sasaki, P. Mehnati, * F. Yatagai, and F. Hanaoka
Since the distribution of ionization is sparse and homogeneous for low-LET radiations but it is dense andinhomogeneous for high-LET radiations, the probability that no ionization occurs within the cell target ismuch higher for the latter than for the former radiation when compared at the same dose level. Assumming a Poisson distribution of hit-events, the fractionof cells whose nuclei are not transversed by iron ions
(4 Gy, 2000 keV/J-L) was calculated to be about 20%.
Previously, we observed CHO cells by time-lapse photography for three to five generations after exposure
to the same dose of iron ions and found that about
20% of the cells (18%: 25/136) showed no division delay at the irradiated generation and continued dividing
with a cell cycle time similar to that of nonirradiatedcells. This suggests that a single hit by an iron ion toa cell nucleus induces an early cellular response suchas division delay. In order to verify this possibility, we
have to identify cellular sites (nucleus or cytoplasm)
through which the iron ions transversed and then determine whether growth arrest did or did not occur forindividual cells.
In this study, we used a CR-39 plastic (solidstate nuclear track detector: Harzlas/TNF-l) as thedetector of hit sites.
First, the optimum etching condition was examined using the plastics which
had already been exposed to iron ions (1-4 Gy:
2000 keY /J-Lm).
When the plastics were etched following a generally
adopted procedure (7N NaOH at 60°C), it took about
30 minutes to produce a microscopically recognizable
pit size (¢: > 1 J-Lm). However, we could treat theplastics under very mild condisions (10 min at 37°C)
using PEW (KOH : Ethanol: Water = 3D 15wt% :65% : 20wt%, recommended by Dr. N. Yasuda: NIRS,
Chiba) as an etching solution. Next, CR-39 plastics
were attached to the bottom outside face of a culture
flask in which Mongolian gerbil fetal (MGF) cells

Faculty of Medicine, Kyushu University146

were grown and treated with PEW solution at 37°C
for 10 min. Two micrographs were taken under aphase-contrast microscope within the same area, one
focused on the cells and the other foccused on the pits
on the CR-39 plastic surface, and then they were superimposed using a computer. An example of suchsuperimposed microphotographs is shown in Fig. 1
where CR-39 plastics were exposed to 1 Gy of ironions. Thus, we can recognize hit sites within thecells exposed to accelerated very high LET heavy ions
(Fe or Ar ions). This study is in progress to elucidate whether early-responding gene products (p53,poly(ADP-ribose)polymerase) are expressed within
the cells whose distinct sites (nucleus or cytoplasm)
have been transversed by accelerated iron ion .

Fig. 1. A superimposed photograph showing MGF cells
and tracks of transversed iron ions .

RIKEN Accel. Prog. Rep. 33 (2000)

Oxidation Degradation of High Density Polyethylene
Irradiated with Ion Beam
T. Oka, F. Yatagai, and Y. Rama
The transformation proceeding over a very longterm was investigated in the inner region of a highdensity polyethylene (RDPE) slab (2 mm thick). A
block of twelve piled samples, the length of which islonger than the range of the ion, was irradiated atroom temperature in air with ion beams. We could notobserve such a phenomenon for low density polyethyFigure 1
lene (LDPE) in our other experiment.
shows the depth profiles of carbonyl group measured
at different dates after irradiation with 135 MeV lu
Ne 10 + in air . These profiles were obtained by microfourier transform infrared spectroscopy (micro-FT-IR)
measurement. The carbonyl group yield in the inner
region is found to increase significantly by a longstorage in air. We have found that it was more marked
for the sample stored for about 3 years. This suggeststhat the oxidation reaction has been taking place
very slowly in the inner region over a long period.
We have confirmed by electron spin resonance (ESR)
measurement that there are no radicals remaining
On the other hand,in HDPE irradiated in air.
the increase in carbonyl group concentration wasobserved even when the same sample was irradiatedin vacuum with 10 MeV lu 0 6 + and then exposed toair. The radicals produced in HDPE by irradiation
under vacuum are stable at room temperature,
but they disappear immediately when the sample
is exposed to air. This finding suggests that thedisappearance of the radicals could be caused by any

0.20

Jan., 1998 (Irradiated)
101, 2700 MeV Ne +, 40kGy, 1712cm , HOPE
Dec., 1998 (Measured)..... May. , 1999 (Measured)§

0.10 '

~
<C

0.05

:a
o

5

10

15

20

Depth [mm]Fig. 1. Depth profiles of the carbonyl group content measured at different dates after irradiation.

oxidation reaction. This oxidation reaction, however,does not immediately produce carbonyl groups. Therefore, any group which does not include a carbonylgroup may be produced, e.g., hydroperoxide -OOH. It
is also known that the degradation reaction in HDPE
proceeds very slowly through the photo- or thermallyinduced cyclic chain reaction. This observation leads
us to the conclusion that there are many initiators that
do not include a carbonyl group, such as the -OOH
group, but which can induce the chain reaction andthey transform very gradually into the structures that
include the carbonyl group by photo- or thermally induced chain reaction.

147

RIKEN Accel. Prog. Rep. 33 (2000)

Heavy Ion Beams: Application to Mouse Mutagenesis (II)A. Yoshiki, N. Hiraiwa, F. Ike, T. Tsukada, N. Fukunishi, M. Kase, Y. Yano, and M. Kusakabe
Mouse mutants are useful animal models for humandiseases. We have attempted to use heavy ion beams
to induce germline mutations in mice. We used two
strategies to induce germline mutations, one is the irradiation of sperm solution followed by sperm injection into the egg cytoplasm to produce G 1 founders,and another is the irradiation of male testes followedby conventional mating to produce G1 founders. These
G 1 founders can be directly analyzed for dominant mutations which exhibit the phenotype in a heterozygous
state. However, a number of abnormalities in humans
and mice are known to be caused by recessive mutations, and can be detected only in the homozygous
state.
In this report, we focused on the screening of recessive mutations with morphological phenotypes during
early embryogenesis. Males of C57BL/6J (B6) strain
mice were anesthetized, held on a plastic board andirradiated with 12C, and 14N ion beams at dosagesof 3 Gy and 5 Gy, respectively. The exposure to theheavy ion beams was restricted to the inguinal regionof the body. Six weeks later successful irradiation of
the testes was indicated by coat color changes in theventral and dorsal skin. These irradiated GO males
were crossed with nonirradiated B6 or BALB / c females
to create G 1 founders. Subsequently, the G 1 founders
were crossed with BALB/c females to produce G2 females, half of which were heterozygous for the newly
induced mutations inherited from the G 1 founders.
Then, G2 females were backcrossed with their fathers,
and sacrificed on day 10 of gestation for the screening of G3 embryos. Morphological abnormalities wereobserved under a dissecting microscope. If the phenotypes are caused by one or two recessive mutations
with high penetrance, similar phenotypes should beobserved repeatedly. Therefore, a G 1 founder which
produced two or more embryos with a similar phenotype was considered as a potential carrier of recessive
mutations.

To date, we have examined 26 G 1 males, and determined that 23 were fertile and 3 were sterile. Withthe 23 fertile G1 males, 110 G2 females became pregnant, and had 985 morphologically normal embryos,
50 morphologically abnormal ones, and 54 absorption
sites. Six G1 males out of23 (6/23 = 26.1%) produced
two or more embryos with the similar phenotypes, andthus were selected as potential mutant carriers (lines
B117, B170, B171, B25, B92, and B134), as summarized in Table 1. Samples of morphologically abnormal
embryos are shown in Fig. 1 A and B. These six G 1
founders have been kept for further breeding to confirm the phenotype heritability and to establish new
mutant lines.

Fig.!. Morphologically abnormal embryos found in G3.

Table 1. Potential mutant lines and their phenotypes.
MutantBeam
Dose
Phenotypes on embryonic day 10
lines
(Gy)
B1l7
12C
5
developmental retardation at E9
B170
12C
5
developmental retardation at E8
B170
12C
5
yolk-sac-like structure without a proper embryo
B171
12C
5
left-turning tail
B171
12C
5
defect in neural tube closure
12C
5
left-turning tail
B25
B25
12C
5
developmental retardation at E9
B92
14N
3
developmental retardation at E8
B 134
14 N
3
developmental retardation at E8
Mutant lines of B170, BI71, and B25 produced two different types of abnormal embryos,
indicating that each G 1 may carry mUltiple mutations.

148

5. Instrumentation

RIKEN Accel. Prog. Rep. 33 (2000)

Design of Liquid-He-Free Superconducting Solenoid Coils forElectron Cyclotron Resonance Ion Source
T. Kurita, T. Nakagawa, T. Kawaguchi, and S. M. Lee
In recent years, we have constructed a facility forexperiments to study the dynamic behaviors of metalclusters shch as fission and multifragmentation. Oneof the main features of this facility is the production of multiply ionized clusters with soft peripheral
collisions of highly charged ions with metal clusters.
This method allows the multiple ionization of a metalclusters without strong additional excitation. 1) This
offers the possibility to study the dynamic behavior of a metal cluster. To produce an intense beamof highly charged ions for this experiment, we constructed an electron cyclotron resonance (ECR) ion
source which consists of liquid-He-free superconducting solenoid coils and a permanent hexapole magnet. 2)
Solenoid coils are used for axial plasma confinement
in an ECR ion source. A superconducting magnet provides a high magnetic field which can't be achievedby room-temperature magnets, and a higher magnetic
field makes an ECR ion source deliver highly charged
ions. 3 ,4) One of the main features of this source is theuse of Gifford-McMahon refrigerators for cooling thesolenoid coils instead of liquid-He. This feature enables
lower cost, lesser complexity and greater compactness
than those of conventional superconducting magnets
produced using liquid-He. A schematic drawing of our
superconducting coil system and the highest axial magnetic field profile are shown in Fig. 1. The magnetic
system for the axial magnetic field consists of a set offour solenoid coils divided into three groups. The central one operates in a reverse current to increase themirror ratio of the axial magnetic field. These superconducting coils have the following characteristics:(1) Internal diameter of all coils: 290 mm(2) External diameter of the coils other than thecentral coil: 445 mm(3) External diameter of the central coil: 380 mm(4) Thickness of the coils other than the inner coilon the injection side: 80 mm(5) Thickness of the inner coil on the injection side:
48.1 mm(6) Conductor: NbTi/Cu(7) Maximum current density: 100 A/mm 2(8) Axial mirror-to-mirror distance: 400 mm
Two refrigerators, a low-power one and a high-power
one, are used. The low-power refrigerator cools thecurrent leads and prevents heat invasion of the solenoid
coils through the current leads. The high-power refrigerator cools the solenoid coils via a cooling conductor
to the temperature of 4 K. The cryostat is enclosed ina 5 cm-thick iron yoke. When using the refrigerators,
it is necessary to minimize the unbalanced electromag-

Current Lead

4.2K1s0K Refrigerator
20Kl80K Refrigerator

Thermal Shield~-V",rllllrr ChamberSuperconducting
Solenoid Coil

Thermal Insulating Support

RF 14.SGHz

3.0- - --

Calculated Profile

2.5
2.0

1.5
1.0

0.5
0.0 ~==;:::=---,---,---.----.--.--~r=====;
o200
400 600
800-800-600 -400 -200

Fig. 1. A schematic drawing of the ECR ion source using
liquid-He-free superconducting solenoid coils and axial
magnetic profiles. The solid line indicates the calculated profile obtained using code-Opera. The squaresymbols indicate the measured magnetic profile. The
current density of both profiles is 95 A/mm 2 .
netic force which must be supported by thermal insulating supports, because of the associated low coolingpower (--,..,1 W at 4.2 K). Our conclusion in the design was that the unbalanced axial force should be lessthan 15 kN. To minimize the force, we studied the coilarrangement, the axial position of the yoke and theoperation conditions using code-OPERA.
Figure 2 shows a cross-sectional view of our superconducting solenoid coils and their electrical connections. The unbalanced electromagnetic force is maximum when some coils are quenched. To reduce theunbalanced electromagnetic force without expanding
the iron yoke, the injection-side coils consist of twosolenoid coils (Coil 3 and Coil 4), and the extractionside coil (Coil 1) and Coil 4, i.e., the outer of injection-

149

Case

-;

.J..

The electromagnetic force:

14 .4 kN

3.0
Coil 2

2.5

,,

E 2.0
a>
u

'';:;

1.5
Case 2The electromagnetic force:

,,

<l)

c

Ol

ro

::E

Fl

OA/rrun 2

,,

-0

<C

", \

13 .8 kN

1.0
0.5

OA/mm

0.0
-600

-400

-200

0

200

400

600

9SA/mmZ Axis [mm]22OA/rrun 2. ~95A/~2~~

Fig. 2. The injection-side coil is divided and the external aspect of the injection side and the extraction
side coil are connected in series. The magnetic field profile and the unbalanced electromagnetic force
when the forece is maximum are shown in the case of this magnetic configuration.

side coils are connected in series.
The severest conditions, under which the electromagnetic force becomes maximum are the following
configurations:
Case 1: When all coils except Coil 3 are quenchedunder the condition to yield a maximum axial field,
the peak of the magnetic field on the extraction side
vanishes. The magnetic field of 3 T generated by the
induced current in Coil 3 will remain on the injection
side. In this case, the electromagnetic force pushing
Coil 3 toward the injection side will become maximum.
The magnetic field profile in this case is indicated by
the solid line in Fig. 2. Since the position of the peakshifts to the inside, the electromagnetic force will be
reduced compared with an undivided coil.
Case 2: When only Coil 1 and Coil 2 are excited witha maximum current, the electromagnetic force toward
the extraction side becomes maximum. The magnetic
field profile of this case is indicated by the dashed line
in Fig. 2. Because Coil 1 and Coil 4 are connected
in series, there are always two magnetic field peaks
formed on both sides. This property contributes tothe reduction of the electromagnetic force between the150

iron yoke and the coils. .
As an optimized and calculated result, the electromagnetic stress become less than 15 kN , as shown in
Fig. 2. With our magnetic configuration, we can success fully reduce the electromagnetic stress without expanding the iron yoke. The measured unbalanced force
in Case 2 is 13 kN. This is consistent with the calculated value. If the injection-side coil is not divided,and Coil 1 and Coil 4 are not connected in series, thenthe electromagnetic force will be greater than 30 kN insome cases. To summarize, it has been demonstrated
that we can reduce the electromagnetic force between
the iron yoke and the solenoid coils, and we have succeeded in designing a com pact magnetic system for an
ECR ion source.
I'V

I'V

References
1) F. Chandenzon et al.: Phys. Rev. Lett. 74 , 3784 (1995).
2) T. Kurita et al.: RIKEN Accel. Prog. Rep. 31, 156(1998) .
3) R. Geller: Annu. Rev. Nucl. Part. Sci. 40, 15 (1990).
4) G. Ciavola and S. Gammino: Rev. Sci. Instrum. 63,
2881 (1992).

RIKEN Accel. Prog. Rep. 33 (2000)

Automatic 18F Supply System for a Slow Positron BeamF . Saito, N. Suzuki, J. H. Kim , Y. Nagashima, T. Kurihara, Y. Itoh, T. Hyodo, and A. Goto
The spin-polarized slow positron beam is a promising probe for surface magnetism. A spin-polarized
positron beam is conveniently produced using a {3+decay radio-isotope (RI) source. However, the activity of 22Na which is routinely used, is at most 6 GBq.
Recently we have developed a practical way of producing an 18F (half-life 110 min, (3+ endpoint energy
635 ke V) positron source for use in materials research.
To perform continuous measurements for a few days,
however, the process of fabricating the source has tobe simple and rapid. In the present paper, we report an automatic system which rapidly supplies an
18F positron source produced by the AVF cyclotron at
RIKEN.
18F is produced via the 180(p, n)18F reaction. The
apparatus used is similar to that used routinely forthe production of 18F as a PET (Positron Emission
Tomography) source. A 14-MeV proton beam from the
AVF cyclotron is used for the bombardment of liquid
H 218 0. The activity of 18F is about 4 GBq after anhour of proton irradiation at 2 j.LA. The 18F solution
is automatically transferred by He gas at a pressureof 1.5 atm through a Teflon capillary from the target
container in the AVF cyclotron vault to the experimentvault downstairs.
An automated electro deposition and source-supply
mechanism, which is controlled by a personal computer, is shown in Fig. 1. It has two rotatable discs.
One serves as a turntable which carries 12 electrodeposition cells made of platinum. The cell acts as acathode as well as a vessel for the 18F solution. Twelve
graphite rod anodes of 3 or 5 mm are installed on
the side of the second disc, which is perpendicular tothe horizontal turntable, rotatable and movable vertically. When the cell is filled with the 18F solution,
the turntable rotates to set the cell at the position forelectro deposition, directly below the source windowof the slow positron beam apparatus. Then the second disc descends until the end of a graphite rod dips
0.2 mm below the surface of the solution. The position of the liquid surface is detected by monitoring theelectric current passing through the graphite rod. The
typical electro-deposition time is about 15 min. Afterthe electro deposition, the vertical disc is raised to theoriginal position and rotated by 180 degrees. It is thenraised farther about 7 mm so that the graphite rod is
close at 1 mm to the positron incidence Ti window of
the beam apparatus. The source is placed outside thebeam apparatus so as not to break the vacuum in theapparatus. The entire procedure takes only 20 min
including the liquid transfer time and the 15 min ofelectro-deposition.

AW18 Cyclotroo
1-1

Slow Positron Beam
!

i

I~

!

modera~«"·i;.:·····.j................

0 (p, n) 18F

cap i II aryelectrodeFig. 1. Figure of automated electro-deposition and source
supply system, cells are placed on a turntable. Carbon
rods are placed on the side of a vertical rotatable disc.
18F solution is transferred through the capillary.

While 18F is being electro deposited and used asa source, the next batch of 180-water is loaded in thetarget container and irradiated by protons. In this way,
the 18F source is supplied continuously throughout theexperiments.
The highest efficiency of electro deposition was 97%
using 2 GBq 18F solution deposited on a 5 mm¢>graphite rod for 30 min. The fraction of the positrons
emitted from of the surface was 45%. Thus, as muchas 42% of the {3+ from the 18F in the 180-water canbe used as a source of the slow positron beam.
The maximum activity of 18F was estimated fromthe density of the 19F carrier which was used forelectro-deposition. it was three orders of magnitudelarger than that .of 2 GBq 18F. Since both 19F and
18F are electro deposited with the same efficiency, we
expect that an 18F activity of at least 2 TBq can beelectro-deposited on a 5 mm¢> graphite rod, provided
we produce 18F with such an activity. For example, if
a small cyclotron commonly used for PET, having a
proton beam current of 50 j.LA, is available, a positronsource of 100 GBq can be easily produced and about
10 7 slow positrons per second would be produced witha tungsten moderator.

151

RIKEN Accel. Prog. Rep. 33 (2000)

Design and Simulat'ion of an Electrostatic Spin-Polarized Positron
Beam System for Surface Magnetism Studies
J. H. Kim, N. Suzuki, F. Saito, Y. Nagashima, T. Kurihara, A. Goto, Y. Itoh, and T. Hyodo

Spin-polarized low-energy positrons are considered
to be useful as probes for studying electron spin statesof both surface and bulk materials. Positrons are polarized along their momentum directions when they are
emitted from a radioactive source. I) The formation of
positronium (Ps, an electron-positron bound system)
can be distinguished from the formation of different
electron spin states due to the spin-dependent interactions between positrons and electrons on the surface.
This method has the advantage of combining spin sensitivity and surface selectivity. Recently, a positronsource of I8F (half-life 110 min, Emax = 0.635 MeV)
has been developed for a polarized slow positron beam
at RIKEN. 2 )We are in the process of designing an electrostatic
positron beam system in combination with a spin rotator that can change the spin direction of the positrons
without changing the beam optics. This design of thebeam system can will be applied to the investigation ofboth surface and interface magnetism. Moreover, thebeam system may be applicable to studies of polarized low energy positron diffraction or polarized Augerlineshape.
An overview of the positron beam optics is shown in
Fig. 1. Positrons from a moderator are extracted andaccelerated in a spin rotator, bent 90° by a parallelplate analyzer, and finally focused onto the target by aseries of electrostatic lenses. For the rays of positrons,
we have chosen 33 trajectories (ranging from -80° to+80°) which are evenly spaced on the moderator witha diameter of 6 mm in the x-y plane. The distance fromthe parallel-plate to the sample is about 1500 mm. The
spatial separation prevents the ,-rays, emanating fromthe source region, from reaching the sample.
After spin-polarized positrons are extracted from amoderator (A), they enter the spin rotator (B) where
the angle of the positron spin direction rotates along
the magnetic field due to Lamor precession, while theirpath is not changed. The parallel-plate mirror (D)bends the positron beam 90° in order to prevent thefast positrons and ,-rays emitted by the source fromreaching the sample. Although the positron's momentum direction is changed, its spin direction remains thesame in an electric field. By the combination of thespin rotator and the parallel-plate bender, both longitudinal and transversal spin components of positrons
can be adjusted at the sample.

152

(A)

t t Positron spin

(X)

(y)

direction

Fig. 1. An overview of the positron beam optics. The
positrons were traced through the beam optics using
SIMION, which is a charged-particle trajectory program with space charge effects neglected. Positrons
from a moderator are extracted and accelerated intoa spin rotator, bent 90° by a parallel-plate analyzer,
and finally focused onto the target by a series of electrostatic lenses. The arrow indicates the direction of
positron spin in the case of 90° rotation at the spin rotator. Three different views are shown: side view (X),front view (Y) and top view (Z).

The source-moderator chamber is insulated from thesample chamber and floats at voltages from 0.1 to
30 kV to accelerate positrons while the sample is maintained at ground potential. The voltages at the end ofa linear-type accelerator (F) are adjusted to vary the
positron beam energies. The beam diameter at the
sample (H) is simulated to be 2-6 mm in the range ofbeam energy from 0.1 to 30 ke V. A set of lenses witha 20 mm inner diameter is used to transport the accelerated positrons onto the sample through the electromagnet (G) that will produce a magnetic field at
the sample. The observation of reflections of positrons(lower than 2 keY beam energy) near the sample when
12 KGauss is applied indicates that further consideration of beam design is required for a better positronpolarimeter.
References
1) L. A. Page and M. Heinberg: Phys. Rev. 106, 1220
(1957).
2) 1. Fujiwara, Y. Itoh, R. Iwata, F. Saito, and A. Goto:
Appl. Surf. Sci. 149, 30 (1999).

RIKEN Accel. Prog. Rep. 33 (2000)

Calibration of Beam-Line Polarimeter at Ed = 140 and 200 MeV
T . Uesaka, H. Sakai, H. Okamura, A. Tamii, Y. Satou, T. Ohnishi, K. Sekiguchi, K. Yakou,
S. Sakoda, N. Sakamoto, T. Wakasa, K. Itoh, and K. Suda
The deuteron polarimeter, which is based on the d +p elastic scattering, was calibrated at Ed = 140 and

200 MeV.
The d + p elastic scattering has several advantages
in polarimetry for an intermediate-energy deuteron
beam: (1) It is expected to have large vector and tensor analyzing powers. (2) A high signal-to-noise ratio isattainable because the coincidence measurement of thescattered deuterons and recoiled protons is applicable.
(3) We can use a polyethylene (CH 2 ) film as a "hydrogen target" because the coincidence measurement
described above makes the contribution from carbons
in CH 2 less important. A thin CH 2 foil (",,50 J1m) is
nondestructive to the beam quality, easy to use, andinexpensive, therefore, it is desirable as a target for abeam-line polarimeter.
In the calibration measurement , the polarizations ofa deuteron beam were measured using a low-energy
polarimeter 1 ) before acceleration in the Ring cyclotron.
It is assumed that depolarization during the acceleration process is negligible. It should be noted that wehave recently carried out the measurement of absolute polarization via the 12C(d~ a)loB*(2+) reaction 2)
independent of this assumption. The typical beam polarization was 70-80% of the ideal value.
A I-mm-thick polyethylene target was bombarded
by the polarized deuteron beam. Scattered deuterons
and recoiled protons were detected in coincidence withplastic scintillation detectors. A schematic depictionof the detector setup is presented in Fig. 1. Four setsof deuteron and proton detectors, Left, Right, Up, andDown, were used to reduce systematic uncertainties inanalyzing powers (only the Left and Right detector sets

abeam

o.

0 .5
!l a 0<1'..>-' 0.0

- o.S

-.,

0

..

.£

··· · ····· ··· ···········2

~'-

0

~

~

0 .8
0 .6
~

0 .4

<t:

0.2
O.O

.. ~

-0 .2 F-+-+--+-+-++-+--+--+--+--+-+--+---+-1-+->-+--+--+-+-+-+-+-+-+--+-t-+-r+--+--+~~
0 .2.... · ··· ······ ··········1 ··· ];.. ·······

2!lLr•• ~

.~"..

-0.6

I·l

-0.8 ~~~~~~~~~~~~~~~~~~~

o

so

100

so

150

100

150

8 0m [deg]Fig. 2. Analyzing power data (.). Left and right panels
represent data at Ed = 140 and 200 MeV, respectively.
Open circles (0) represent data at slightly different energies (Ed = 144 and 191 MeV) taken at Saturne. 4 )Table 1. Analyzing powers used to measure the beam polarization.

Ay
Ayy
Axx

Ed = 140 MeV

Ed = 200 MeVBern = 110°
-0.519 ± 0.005
0.541 ± 0.005
0.017 ± 0.007

Bern = 82.5°-0.332 ± 0.005
0.306 ± 0.005-0.313 ± 0.006

are illustrated in Fig. 1). Details of the experimental
setup are described in Ref. 3.
In Fig. 2, vector (Ay) and tensor (Ayy and Axx) analyzing powers for the d + p elastic scattering are shown.
Full and open circles represent the present results andthe data taken at Saturne,4) respectively.
The angles used in the polarimeter were chosen to
be Bern = 110° and 82.5° at Ed = 140 and 200 MeV,
respectively. The analyzing powers at these angles arelisted in Table 1.
References

Fig. 1.
Detector setup of the deuteron polarimeter.
Deuteron and proton detectors (plastic scintillation detectors and photomultipliers) are placed at forward andbackward angles, respectively.

1) T. Uesaka et al.: RIKEN Accel. Prog. Rep. 32, 161(1999).
2) K. Suda et al.: RIKEN AcceL Prog. Rep. 33, 154(2000).
3) N. Sakamoto et al.: Phys. Lett. B 367, 60 (1996).
4) W. G. H. Witala et al.: Few Body Systems 15, 67(1993).

153

RIKEN Accel. Prog. Rep. 33 (2000)

Absolute Calibration of the Deuteron Beam Polarization atan Intermediate Energy via the 12C(d, a) Reaction
K. Suda, H. Okamura, N. Sakamoto , A. Tamii, T. Uesaka, T. Ohnishi, K. Sekiguchi,
J. Nishikawa, H. Kato, M. Hatano, and H. Sakai
The polarization of the deuteron beam accelerated
by AVF and Ring cyclotrons is measured using a polarimeter (high-energy polarimeter) , which applies thed-p elastic scattering as a polarimetry. 1) The analyzing
powers for the reaction were calibrated against the polarization measured using the 12C(d,p)13C reaction at
the exit of the AVF cyclotron. 1) However, the analyzing powers calibrated in this manner inevitably havesystematic errors because the uncertainty of the analyzing powers for the reference 12C( d, p) 13C reactionis already significant in amount. Moreover, systematic
uncertainty also arises from the long-term instabilityof the polarization because measurement of the beampolarization and the analyzing powers for the d-p elastic scattering cannot be carried out simultaneously at
RARF. Therefore, it has become necessary to calibrate
the high-energy polarimeter directly using nuclear reactions , the absolute values of the analyzing powersof which are unambiguously known. Although such areaction is not known for the vector analyzing power ,a few reactions exist for the tensor analyzing power.
One of those is the 160(d, ex) 14 N(0-, 4.92 MeV) reaction, and was used at a low energy.2) At intermediate
energies, however, it is considerably difficult to use thereaction since an energy resolution better than 200 ke V
is required and the cross section is rather smaller thanthat at a low energy. As an alternative, we propose to
use the 12C(d, ex)10B reaction for calibrating the absolute value of the polarization. In this reaction at 0°, if
the final state of lOB has natural parity except for 0+,
it can be shown that the tensor analyzing power Azz
is unity due to the parity conservation. Among thelevels of lOB, the 2+ state at 3.59 MeV excitation isadvantageous because energy differences between adjacent levels are more than 1 MeV. Moreover, even if
the tensor polarized beam has a component of vector
polarization, it does not influence on the measurementof the tensor polarization because Ay = 0 at 0°.
The absolute calibration of the high-energy polarimeter using the above reaction was carried out fora 270 MeV deuteron beam. For the measurement ofthe (d , ex) reaction, we used the spectrometer SMART.
A self-supporting natural-carbon foil with a thicknessof 10.94 mg/cm 2 was used as the target. The scatteredparticles were momentum-analyzed by the SMART
and detected using a multiwire drift chamber and threeplastic scintillators at the second focal plane. The exparticles were identified using the light output fromthe plastic scintillators. A typical excitation-energy
spectrum is shown in Fig. 1. The cross section for the154

2+ state is 5 Jlb/sr at 0°. In the analysis, we limited the scattering angle to less than 1° in a laboratory system because Azz for the (d, ex) reaction varies

12C(d,a)10B at Ed. =270MeV
8 1ab =oo - 4°
0.00,3+:> 2000
Q)~.,......,

1500

0
~
rJ)

...j...J

~
;j

0
U

1000

500

O--~~~~~J-~~~~~-k~~~~

-2

0

2

4

6

B

Excitation Energy (MeV)
Fig. 1. A typical excitation-energy spectrum for the
12C(d, a)lOB reaction at (Jlab = 0°_4° is shown withsolid circles. The broken line shows the result of a Gaussian fit for each peak. The solid line shows the sum of
the fit results. A hatched peak represents the 2+ stateof interest at the excitation energy of 3.59 MeV.

Ayy
0.6

9+
0.4

•

•

•

+

+

+

-0.2

Axx
-0.4

~.

+

•

• t

•

-0.6

60

80

100

120

140

8 CM (deg)Fig. 2. The analyzing powers Ayy and Axx for the d-p
elastic scattering. The present data are indicated byopen diamonds. The data obtained from Ref. 1 are
indicated with solid circles.

considerably near 0°. The horizontal and vertical angular resolutions of the SMART, which are 0.19° and
0.22° , respectively, are sufficiently good. Simultaneously with the measurement of the (d, 0:') reaction, theasymmetry of the d-p elastic scattering was measured
using the high-energy polarimeter. With the polarization obtained using the (d,O:') reaction, the analyzing powers Ayy and Axx for the d-p elastic scattering
were determined. The analyzing powers are comparedwith the data reported in Ref. 1. The results are ingood agreement with the statistical errors, as shownin Fig. 2. The systematic errors are estimated to beequal to orstatistical errors.
In the detection of the Q particle, the signal-to-noise ratio was very low due to the small cross section.
The beam intensity was limited to less than 20 nA toprevent the loss of detection efficiency. As a result, thestatistical errors of the present data are twice as large
as those in Ref. 1. In order to improve the statisticalaccuracy, we will repeat the experiment again with increased beam intensity and reduced background. Further, we plan to calibrate of the high-energy polarimeter at 140 MeV.
References
1) N. Sakamoto et al.: Phys. Lett. B 367, 60 (1996).
2) S. Kato et al.: Nucl. Instrum. Methods Phys. Res. A
238, 453 (1985).

155

RIKEN Accel. Prog. Rep. 33 (2000)

Calibration of 3He Polarization Using
Electron-Spin-Resonance Method
S. Yamamoto, T. Uesaka, T. Wakui , H. Sakai, and Y. Yano
The RIKEN spin-exchange-type polarized 3He target was applied to nuclear physics experiments in1996 1 ) and 1998. 2 ) It is important to accurately det ermine the absolute polarization of 3He in such applications. At present , the most common method of 3He
polarimetry is based on nuclear magnetic resonance(NMR) of adiabatic fast passage (AFP), which we areusing. Through this method, however, we can only
determine the relative value of polarization.
To calibrate the absolute value of polarization, we
measured Boltzmann polarization signals from protons
in a sample of water using AFP-NMR (proton NMR)
under the same conditions as those used to measure
3He polarization. Though it is easy to measure theproton NMR signals , there are considerable systematic errors due to the small strength of proton NMR
signals. Thus, we have introduced a method based on
the frequency shift of the Rb electron-spin resonance(ESR).3)
The frequency shift is proportional to the polarization of 3He, the density of 3He, and the Rb- 3He spinexchange constant 1'\,0 . The value of 1'\,0 is determinedaccurately as 4.52+0.00934 xT [oC].4) The uncertainty
in 1'\,0 is l. 5 % at 175°C. 4) Therefore the precision of thiscalibration depends on the precision of measurementsof the Rb ESR frequency shift and the density of 3He.
We measured the frequency of Rb ESR in a magnetic field of 30 G as follows: firstly, 85Rb atoms in
the cell , containing 3 amagats t of 3He gas and a few
mg of Rb metal, were optically pumped with circularly polarized light ((7 +) tuned to the D1 transition(795 nm) from the ground state 5 2 8 1 / 2 to the excitedstate 52 P1/2' The population of all the Zeeman sublevels in the ground state was thereby depleted except
for the mp = +3 Zeeman sublevel of the F = 3 hyperfine state. This led to a decreased absorption of
the pumping laser light; consequently, the fluorescenceintensity was markedly reduced. Secondly, we appliedan RF field to repopulate the depleted mp = 2 levelat a frequency corresponding to the ESR transition
between mp = +2 and +3 , and the fluorescence intensity was immediately increased. Therefore, the Rb
ESR frequency could be determined as the peak position in the fluorescence spectrum by scanning the
RF frequency. In this experiment, the frequency was
locked at peak position using a feedback system, andwas measured by a frequency counter.
The measurements of the ESR frequencies were performed in the cases where 3He nuclear spin K is parAn amagat is a unit of density corresponding to 1 atm at
O°C

156

aIle I (jK jB) and antiparallel UK j B) to a magnetic
field B. Figure 1 shows the ESR frequency which wasalternately obtained for each case. The frequency shift/:1lJ is given with the Rb ESR frequencies lJ(jKiB) andlJ(! K i B ) as/:1lJ = lJ(j K i B ) -lJ(! K i B )

lJB9s

81T

3

h (21 + 1) 1'\,0 3 lJHe [ HeJP3He,
where lJB is the Bohr magneton, 9s is the electron 9factor , 1 is the nuclear spin of 85Rb, [3HeJ is the densityof 3He, and P 3He is the polarization of 3He. Figure 2
shows the frequency shift and polarization as a function of the NMR signal. In Figs. 1 and 2, error bars
are as large as 5 kHz , which indicate an uncertainty inpolarization of about 40%. This large uncertainty is
due to the instability of the magnetic field. An error
12.21 2N>.
uc

12.206cr"
Q)......
t.L.

12.204

et:::

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i

i

i

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f

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12.200++6 12.208
Q)
;:j

L

L

12.210

~

0

5

10
15
Time [arb. units]

25

20

Fig. 1. A typical set of ESR data. We measured the ESR
frequencies in the cases where 3He nuclear spin K isparallel (TK TB) and anti-parallel UK TB) to a magnetic field B .

30

14
N 12

~

24

:.c

18 [

""0

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CI)

>.
u

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Q)

;::l

0'

~

~

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0

8

t'ol

~

6

12

4

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u.l

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0

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0.2

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NMR Signal Amplitude [V]Fig. 2. The relationship between the frequency shift (polarization) and the amplitude of the NMR signal.

of 5 kHz corresponds to an instability of 20 mG. To
decrease the uncertainty of polarization to less than
5%, we have to decrease the instability to less than
3 mG. We are planning to improve the stability of themagnetic field by introducing a feedback circuit witha magnetometer.

References
1) T . Uesaka et al.: RIKEN Accel. Prog. Rep. 30, 139(1997) .
2) M. Kurokawa et al.: private communication.
3) B. C. Grover et al.: Phys. Rev. Lett. 40, 391 (1978).
4) M. V. Romalis et al.: Phys. Rev. A 58, 3004 (1998).

157

RIKEN Accel. Prog. Rep . 33 (2000)

Response of an Imaging Plate for Heavy Particles
S. Gunji, H. Sakurai, N. Sato, K. Morimoto , F. Tokanai, 1. Tanihata, Y. Wakasaya, and T. Kato
We are investigating the response of an imaging
plate (IP) for heavy particles for use as a detector ofultraheavy cosmic rays.l ,2) It is well known that photostimulated luminescence (PSL) occurs when the positions injected with heavy particles are illuminatedusing a laser. By detecting the PSL value using aphotomultiplier, we can obtain information about the
injection positions of the particles and the depositedenergy. However , due to the fading effect, information on the deposited energy of the positions fades aswith time. 3 ) Therefore, it is very important to detect
the PSL in real time. In order to do so, it is necessary to know where the particles are injected. We plan
to locate the position using the prompt luminescence 4 )from the IPs. We irradiated the IPs with Bi 10 A MeV
and Kr 70 A MeV in the RIKEN cyclotoron accelerator, and attempted to detect the prompt luminescencefor each particle.
For this experiment, the setup shown in Fig. 1 wasused . The four-channel multianode photomultipliermounted on the side of the IP was used to detect the
prompt luminescence , and the plastic scintillator in
front of the IP was used to confirm that the heavy
particles passed through the IP. The flux of the heavy
particles was adjusted to about 1000 counts/sec for an
area of 30 cm 2. The trigger condition was the coincidence of the plastic scintillator with the four channelThesignals of the multianode photomultiplier.
output signals from each channel of the multianode

Plastic

Multianodephotomultipliert"\:Gate Signal
Logic Module

Fig. 1. Experimental setup , consisting of the IP, the plastic
scintillator, and the four-channel multianode photomultiplier.

158

200

175

150

/25

fJl JOO

§
c3

75

50

25

250

500

750

1000

1250

J500

1750

2000

ADC channel
Fig. 2. Summed pulse height distribution for the four channel signals. The clearly observed broad peak is due tothe injection of Bi 10 A MeV.
photomultiplier were acquired by the CAMAC systemusing the trigger condition.
Using this setup , we succeeded in detecting theprompt luminescence of the particles for both Bi 10 A
MeV and Kr 70 A MeV. In Fig 2, the summed pulse
height distribution for all four channel signals is shown.
A broad peak which corresponds to the deposited energy of Bi 10 A MeV, is clearly observed.
In a future work, we will investigate the proportionality of the prompt luminescence to the deposited energy. Moreover, we plan to identify the injection positions by mounting four photomultipliers on the corners of the IP and determining the differences between
their signals. We will also investigate the wavelengthand the time profile of the prompt luminescence.
References
1) G. Kanase et al.: IEEE Proc., N12-6 (1998).

2) S. Gunji et al.: IEEE Proc. , Nll-4 (1999).
3) A. Taniyama et al.: Electron Microsc. 45, 232 (1996).
4) K. Sakasai et al.: Proc. 7th Int. Conf. on Nuclear Engineering, Seattle (1999).

RIKEN Accel. Prog. Rep. 33 (2000)

Development of Time-of-Flight Detector with Streak Camera
F. Tokanai, K. Morimoto, M. Kurata-Nishimura, I. Tanihata, and S. Yamada*In high-energy physics, time-of-flight (ToF) measurement has commonly been used to determine themass and energy of heavy ions. One of the main requirements for any ToF detector is good time resolution. A time resolution of up to about 150 ps has beenachieved. A time resolution of 150 ps allows for a separation of masses of around 4 amu with an energy of 6.8
Ge V for aIm flight path. However masses of around
200 amu can be separated only up to 136 MeV. 1 ) Recently, construction of the radioactive ion beam facility(RIBF) was begun at RIKEN. 2 ) In this facility, heavy
ions will be accelerated to energies up to 400A Me V
for light nuclei and 150A MeV for the heaviest nuclei.
Therefore, if we separate masses of around 200 amu
an the energy of 30 GeV, a time resolution of 10 psis required for aIm flight path. For this purpose,
we have been developing a novel ToF detector with a
10 ps time resolution, which utilizes a streak camera.
The configuration of the new ToF system is shown
schematically in Fig. 1. This system consists of two
identical sets of streak cameras (systems 1 and 2). The
system 2 streak camera is placed at a distance L (m)from system 1. These systems are tilted at 45 degrees
with respect to the heavy-ion path. Foil is mounted
at the center of each system to emit secondary electrons. This foil divides each streak camera system

Streak Image
Detector

into a streak-image detector and a center-image detector. An acceleration mesh is mounted on both sidesof the foil at a distance of 2.7 mm. In the streakimage detector section, the secondary electrons fromthe foil are accelerated by the electric field of the meshand focused by an electronic lens. These electrons are
swept by applying a 100 MHz sine wave voltage to thevertical and horizontal diffraction plates. The sweptelectrons image appears as a circle of 16 mm diameter on the phosphor screen. In the center-image detector section, the secondary electrons are accelerated,focused by an electric lens, and directly impinge on thephosphor screen (not swept). The position of the electron image on the screen represents the center of thecircle from the streak-image-detector section. Theselight images for both detector sections are recorded bya two-dimensional position-sensitive detector such as
an image intensifier.
Since the sweeping electric fields of each system
are operated at the same period (angular velocityw), when a heavy ion passes through this system, we obtain the streak image of eo = wto ande1 = w(to + cSt) on a circle for system 1 and system 2,
respectively.
Using the relationship between 6t
and L, we can obtain the velocity of a heavy ion.
Therefore, this system can be used as a ToF detector.

RF Signal Supply(lOOMHz)~el~;;'(tO+~t)
Screen--......,.,.,....,....,....·--,

8 1 - 80= 2D1t + W 8t"'"Streak Camera'"",,~ystem2

6J.Ull Cupper Mesh
(Open Fraction 50%)

Fig. 1. Schematic view of the new ToF detector system.
National Institute of Radiological Sciences

159

In order to investigate the performance of the ToF
system, we carried out test measurements using one
streak camera system for the heavy-ion beams. The
performance test of the streak camera system wascarried out using lOB and 12C beams of 2.5A energy
MeV from the RIKEN heavy-ion linear accelerator(RILAC). The streak and center images on thephosphor screen were lens-coupled to a CCD camera.
Figure 2 shows the streak image obtained for thelOB beam at 2.5A MeV energy.
The center imageis also shown in Fig. 3. The beam rate was about
10 4 particles/so We used a gated signal of III ms
width for the CCD, thus a total of 1110 events was
acquired. These images are binned in a 2 x 2 CCDchannel (13.4 f.Lm x 13.4 f.Lm). We can see two clusters
The bright clusterin the center-position image.
was defined as the focused lOB beam profile witha diameter of about 2 mm and the faint cluster as
the effect of the beam attenuator at the beam line.
We could not distinguish the two images from the
CCD images of the ZnS scintillation light. Therefore,

979 .00

499.0019.00.•. J.".

400

r

;
' ,I

,- ~

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1"

I
'j,

~

o

100

200

300

....

:,

400

500

600

I X-axis I
Fig. 2. Streak-position image for lOB beam at 2.5A MeV
energy.

160

622.00342.00

62.00

500

400

~ 300

~
~

>. 200
100

o

100

200

300

400

500

600

I X-axis I
Fig. 3. Center-position image for lOB beam at 2.5A MeV
energy.

the center-image part of this system will be useful formonitoring both the position and the shape of theheavy-ion beam spot. Moreover, the position information of a heavy ion reduces the uncertainty of theflight path between two ToF systems, which is causedby angular straggling in the target. The streak images
corresponding to the center-position images are clearlyseen in Fig. 2. However, it is not a circular image, but
an elliptical one. This is due to the interface between
the horizontal and vertical electric fields in the sweep
region in the streak image section. This can be fixedby using an electric shield between the horizontal andvertical electrode.
We are currently working on improving the detection
efficiency and the event acquisition rate.
References
1) G. W. Buyler, A. M . Poskanzer, and D. A. Landis: Nucl.
lnstrum. Methods. 89, 189 (1970).
2) I. Tanihata: J. Phys. G: Nucl. Part Phys. 24, 1311
(1998).

RIKEN Accel. Prog. Rep. 33 (2000)

Development of a New Photon Detector System for
Nuclide Identification
K. Uchiyama, K. Ohta, T. Ishizuka, K. Akimoto,* S. Aoyagi,* T. Hirose,* K. Morita, and N. Sugimoto*Over the past few years, several experiments for producing and identifying new isotopes have been performed by the a-a delayed coincidence method using
the RIKEN gas-filled recoil separator (GARIS).1-3)
This method is very useful for identifying new isotopes when the a-decay of the daughter nucleus iswell known. However, there are cases in which thismethod is not effective, such as when the a-decay energies of the daughter nucleus are unknown, or when
the branching ratio of a-decay for its daughter nucleus
is much smaller than the detection limit. In such cases,
additional information, for example, the characteristic X-rays oriented from reaction products, measured
around a focal plane detector of the separator, is required for identification.
CdTe and CdZnTe semiconductor detectors are suitable for measurements of rare events such as the production of new isotopes because of the high efficiency
per volume due to their large absorption cross section compared with those of conventional X-ray detectors, Ge or Si(Li) detectors. The band gap of CdTeor CdZnTe is sufficiently wide to allow operation atroom temperature, so it is expected that low runningand maintenance costs will be achieved. However, the
CdTe and CdZnTe detectors have several problems,
including a low energy resolution compared with Ge
or Si(Li) detectors, and difficulty with producing large
crystals. As a result of the latter, although the priceof one CdTe or CdZnTe crystal is much lower thanfor a Ge crystal, the size of a commercially available
CdTe or CdZnTe crystal is much smaller than that ofa Ge crystal. In our experiments, X-ray detectors will
be placed around the focal plane detector, so the distance between reaction products which are implantedin the focal plane detector and X-ray detectors will
be restricted by the optical condition of the separator. In addition, the detectors should be placed far
enough from the focal plane so as not to be damagedby charged particles, and yet close enough to the focal
plane to achieve a high detection efficiency. Consequently, the total detection efficiency will be strongly
affected by the detector crystal sizes; we must use
many crystals set around the focal plane detector inorder to cover a sufficiently large solid angle. Thus,
the total price of the CdTe or CdZnTe system will become even higher than that of the Ge system; this is
the problem which must be solved when the CdTe or
CdZnTe detector system is constructed. To find the
optimum solution for our new photon detector, we inDepartment of Physics, Saitama University

vestigated the basic performance of CdTe and CdZnTe.
First, a Schottky CdTe detector 4 ) was tested using
the setup shown in Fig. 1. A single crystal of CdTew hose effective area is 10 mm x 10 mm and thickness
is 0.3 mm was mounted on a boron nitride base. The
vacuum region(-10- 5 torr)
Peltier module

atmosphere

CdTe

Be window/

Drradiation
sourceflangeFig. 1. Schematic diagram of a setup for test experimentsof a Schottky CdTe detector .

CJ)C:::::I

0

<-)

80
70
60
50
40
30
20
10
0
100

200

300

400

500

600

ChannelFig. 2. The ')'-ray spectrum of a 133Ba standard source atroom temperature obtained using the Schottky CdTe
detector. Positive bias, + 100 V, was applied to theindium electrode. The statistics of this spectrum arepoor because the radiation sources are weak.

161

CdTe crystal can be cooled using a Peltier module.
The CdTe detector in the vacuum chamber was irradiated by radiation sources through the 0.5-mm-thickmetal beryllium window. Figure 2 shows the ,-ray
spectrum of a 133Ba standard source at room temperature. The peaks at 359 channel, 387 channel and449 channel correspond to 276.4 keV, 302.9 keV and
356.0 keV, respectively. The value of the full-widthat half maximum (FWHM) in these energy regions isabout 22 keV, and this value is about tenfold that ofa sufficient resolution. Although the energy region ofcharacteristic X-rays is lower, we have not yet achieveda sufficient resolution.
The main reason for insufficient resolution is thelarge electric noise of the preamplifier. It is expectedthat the photon detectors will be placed in muchworse environments with respect to electric noise thanthe present one. At present, only a standard preamplifier which had been used for our silicon solid-state
detectors surrounded by the focal plane detector of the162

GARIS is used, so the development of specific preamplifiers may be necessary. On the other hand, the costof our photon detection system using this CdTe detector may become much higher than that of Ge or
Si(Li) detectors if specific preamplifiers which significantly improve the resolution must be used for eachcrystal. If so, it will be difficult to use the CdTe detector, from an economic point of view. The CdTe
detectors discussed above have many merits, and thus
the improvement of the resolution and other investigations, including the testing of CdZnTe detectors, arepresently in progress.
References
1) K. Morita et al.: Z. Physik A 352, 7 (1995).
2) Y. H. Pu et al.: Z. Physik A 357, 1 (1997).
3) Y. Tagaya et al.: Eur. Phys. J. A 5, 123 (1999).
4) C. Matsumoto et al.: IEEE Trans. Nucl. Sci. 45, 428(1998).

RIKEN Accel. Prog. Rep. 33 (2000)

Development of High-Efficiency Delay-Line PPAC for
High-Energy Light Ions
H. Kumagai, N. Fukuda, A. Ozawa, K. Summerer, and 1. Tanihata
The facilities that produce radioactive secondary
beams by projectile fragmentation need to routinely
measure the positions of a wide range of energetic ions.
For position measurements, two-dimensional parallel
plate avalanche detectors (PPAC) based on chargedivision read-out have been used at the fragmentseparator facilities in RIKEN 1) and NSCL.2) The detectors have proven to be highly versatile and reliable. However, signal pileup becomes a serious problem when counting rates are higher than 5 k S-l forsuch detectors. This is a natural limitation in the caseof slow ion signals. Thus, we have developed delayline read-out models. We have successfully achieved
reasonable position and timing resolution for counting
rates of 10 6 S-l for an earlier mode1. 3) However, due toa smaller induced signal from the electrons, the previous type was effective only for low energies (less than
15 A MeV) or for large Z ions at high energies.
In order to improve detection efficiencies for highenergy light ions, we needed to improve the signal-tonoise ratio of the PPAC. Since it is difficult to enhance
the signal in the delay-line PPAC, the only way to improve the signal-to-noise ratio is to decrease the noiselevel in the PPAC. There are two major noise sources;
one is the noise from external electronic devices, suchas the power supply of pre-amps and turbo-molecular
pumps, and the other comes from internal electronics in the PPAC. To decrease external noise, we carefully mounted the PPAC in such a way that it was
isolated from the beam-line and its vacuum chamber.
The main source of internal noise is the pre-amp. In
order to decrease the noise level, we developed a new
design for the pre-amp, using a low-noise transistor.
We succeeded in decreasing the noise level by a factorof two.
We measured detection efficiencies, position resolution, and time resolution for the newly designed delayline PPAC at the RIPS in RIKEN and the KAOS facility in GS1.
We produced several types of secondary fragments
at the RIPS, namely, lOBe with 75 A MeV, 8Li with 6168 A MeV, and 7Li with 87-91 A MeV. We mounted aplastic scintillator in front of the PPAC to count the
number of fragments passing through. In order to measure the position resolution of the PPAC, we mounted
a small photomultiplier with three fiber scintillators on
the exit window of the PPAC. The distance between
fiber scintillators was 10 mm and the scintillators weresquare in shape with a size of 0.5 x 0.5 mm 2. For the
PPAC, we used C3F8 gas at 30 Torr and flow rates ofabout 6-10 l/h. We achieved about 95% detection effi-

ciency for the above fragments even for a 105 S-l countrate. To obtain the position resolution, we measured
the position spectra of the PPAC coincident with thefiber scintillators. We obtained a 1.2-1.5 mm (FWHM)
position resolution for the PPAC, including the size ofthe scintillators. We also measured the time resolution between the signal of the front plastic scintillator
and the anode signal of the PPAC. The measured time
resolution was 1.6-1.7 ns (FWHM), including the intrinsic time resolution of the scintillator. It was notedthat the flow rate of the gas affects the bias voltage of
the PPAC. For a flow rate of 6 l/h, we achieved 96%
efficiency at 1750 V. On the other hand, for a flow rateof 10 ljh, we achieved 95% at 1820 V. The reason forthe difference is unclear. Probably, it is due to the purity of the gas and/or the out-gas from materials inside
the PPAC chamber. The higher flow rate is preferable
for stable PPAC operation.
In one experiment, we applied high count rates(about 25 k S-l) for about 7 hours to check the longterm stability of the PPAC. During the measurements,
the PPAC was damaged due to discharges. After themeasurements, we compared the damage of the cathodes, with Al and Au platings, due to the discharges.
We observed a marked difference in the trace of discharges. The damage in the case of Au plating as
greater than at in the case of Al plating. The difference may be due to the different melting points forboth metals. Therefore, we chose Al for the final plating. However, the contact between the delay-line andthe cathode plate was formed by Au evaporation tomaintain a good electronic contact.
We installed two new delay-line PPACs at the KAOS

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=.
.

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=~

-0-- PPAC-l ~;.---e-- PPAC-2:=

I i i ,

I i i ii1720 1740 1760 1780 1800 1820 1840 1860
Anode Bias (V)Fig. 1. Bias voltage dependence of the detection efficiency
for thenewly designed delay-line PPAC measured by themixed 8B beam.

163

800
700

]

I

!

:

600

§ 500
400

..d

u
-...

:

...............-~

c:: 300

::l
0

u

200
100
0

.J l
-20

-10

)

\..
o

X(mm)

10

20

Fig. 2.
Position spectra (X-axis) of the newly designed delay-line PPAC coincident with fiber scintillators (0.5 x 0.5 mm 2 size) measured by the mixed 8B
beam.

facility in CSI in order to check the performance ofthe detectors at relativistic energies. We produced
three types of beams, namely 12C with 174 A MeV,
12C with 335 A MeV, and a mixed beam of BB with

164

254 A MeV and 7Be with 216 A MeV, from the FRS facilityat CSI. The typical count rate was about 100 s-l
for the mixed beam. We achieved about 99% detection efficiency for the 12C beams and about 95% detection efficiency for the mixed BB beam. In Fig. 1,
bias voltage dependence of the detection efficiency forthe mixed BB beam is observed. To obtain the position resolution, we measured the position spectra of
the PPAC coincident with the fiber scintillators. We
obtained 1.1-1.2 mm (FWHM) position resolution for
the PPAC , as shown in Fig. 2 for the mixed 8B beam.
We also measured the time resolution between the two
PPACs. The measured time resolution was 1.2- 1.4 ns(FWHM).
References
1) H. Kumagai and K . Yoshida: RIKEN Accel. Prog. Rep.
28 , 127 (1995) .
2) D . Swan, J. Yurkon, and D. J. Morrissey: Nucl. Instrum. Methods Phys. Res. A 348 , 314 (1994).
3) H. Kumagai and I. Tanihata: RIKEN Accel. Prog. Rep.
31, 164 (1998).

RIKEN Accel. Prog. Rep. 33 (2000)

Construction of PHENIX Muon Tracking Chambers
J. Murata, M. L. Brook, D. M. Lee,*1 S. Pate,*2 N. Saito, T. Shibata,
W. Sondheim, *1 M. Sugioka, and C. Velissaris*2
The PHENIX muon arm consists of a muon identifier(MuID), muon magnets and a muon tracker (MuTr).
Muon magnets and MuID panels have been built andinstalled in the experimental hall. 1) In May 1999, a
RIKEN team joined the MuTr construction team towork mainly on: (1) Chamber quality assurance (QA)
system construction, (2) Optical alignment system development, (3) Gas system design and construction,(4) Position resolution evaluation.
Each arm of the MuTr consists of three stations ofcathode-strip tracking chambers, which are mounted
inside the muon magnets. Each station is now underconstruction 1) at factories in BNL, LANL, UNM (U niversity of New Mexico) and NMSU.
(1) The QA test system at the BNL factory, for testing stations 2 and 3 has been built . The QA system
consists of a test system for the high anode-voltage
supply and a cathode-signal readout system for evaluation using the ,6-source. A CAMAC-based data acquisition system (DAQ) has been built and checked using
signals from scintillators. The 32-octant chambers ofstations 2 and 3 are being checked using this system.
The total number of channels is 44544 (cathode strips)
and 26496 (anode wires).
(2) A real time relative-position monitoring system 2)
has been prepared. The initial placement of the chambers is possible to an accuracy of a few millimeters;
however, sufficient resolution can be obtained by measuring the relative alignment of the chambers to within
25 J-lm using the optical alignment system. The role ofthis system is not only to measure the initial alignment, but also to monitor the thermal expansion or
movements of the chambers. The system comprises
an optical fiber connected to a visible-light source, aconvex lens and a position-sensing CCD camera. We
have developed a DAQ system for CCD utilizing commercially available software. The CCD camera has asensing area of 8.8 x 6.6 mm with the effective pixelsof 768 x 493. Therefore, the pixel resolution is approximately 12 J-lm and the centroid resolution is approximately 2 J-lm. We will use seven alignment monitors per chamber. Preparation for the installation isin progress.
(3) The chamber gas supply and recirculation systemdesign has been completed. 3 ) Ar(50%) + CO 2(30%) +CF 4(20%) mixed gas was selected with considerationof non-flammability, Lorentz angle, cathode charge distribution, efficiency and so forth. In order to reducethe cost of the expensive CF 4 gas, a system enabling*1

Fig. 1. Experimental setup of the position resolution measurement for the test chamber at LANL. Another two
drift chambers and a trigger scintillator are located below the test chamber.

almost complete recirculation has been designed using
gas purification filters. Safety precautions with respect
to protect against too high and too low pressure havebeen taken, with particular consideration of the thingas windows of station 2. The system design has been
approved by the RHIC safety review committee andconstruction will start soon.
(4) The position resolution of a test chamber which
has the same strip structure as the real chambers of
the MuTr has been measured. The primary purpose
for constructing the test chamber is to check the performance of the front end electronics before their mass
production. However, this measurement in itself is important because it is the only reference data for the resolution. The cosmic-ray measurement was carried out
in October 1999 at LANL using four delay-line drift
chambers 4) as reference chambers (Fig. 1). The drift
chambers have the position resolutions in the range of
80-100 J-lm. Further calibration and analysis is wellunderway and the position resolution of 100 J-lm is expected for the test chamber.
References
1) PHENIX Muon Arms Status,
September 1999,(PHENIX, Brookhaven National Laboratory, New
York, 1999).
2) M. L. Brooks et al.: IEEE Trans. Nucl. Sci. 44, 683(1997) .
3) J. Murata: Muon Tracker Gas System Design (1999);
http://spin.riken.bnl.gov ;- jiro/mutrgas.html
4) L. G. Atencio et al.: Nucl. Instrum. Methods Phys. Res.
187, 381 (1981).

Los Alamos National Laboratory, USA*2 Department of Physics, New Mexico State University, USA
165

RIKEN Accel. Prog. Rep. 33 (2000)

Status of PHENIX Muon Identifier Mechanics
A. Taketani, V. Cianciolo, *1 H. En'yo, N. Hayashi, T. Ichihara, K. Imai, M . Ishihara,
L. Kotchenda,*2 K. Kurita, Z. Li, Y. Mao, K. Read,*1 ,*3 N. Saito, H. D. Sato,T. Shibata, E . Taniguchi, W. Tian, *3,*4 and Y. Watanabe
The installation and testing of the muon identifier(MUID) for the PHENIX detector was completed in
1998. Since then, we have been maintaining the detectors and designing the gas supply system for thislarge-scale detector. In this article we report on themechanical maintenance of the MUID, focusing on therecovery procedure following a major accident whichhappened in Jan. 1999, and the progress of the gas
supply system design and construction.
The MUID detector plays an important role in the
RHIC spin program 1) as well as in the heavy ion program. The detector systsem cosists of a range stackformed by the sandwiching of five absorber steel plates
and proportional chambers made of plastic larroci
tubes. 2 ) In order to cover a large acceptance of 10
to 35 degrees in () and 360 degrees in ¢ at 7 m fromthe reaction point , the area which must be covered is
10 m high and 13 m wide. The detector covers the forward and backward regions, so-called south and northarms , respectively. We segmented a total of 10 gaps .
Each gap has 6 of panels which are into 60 which areformed a proportional tube array housed in the aluminum cases. The MUID panels were fabricated 3) andinstalled in the fall of 1998.4,5)
The PHENIX experimental hall was flooded on
Jan. 2, 1999.
The rapid increase in temperaturemelted the accumulated snow on the ground, but did
not melt the ground ice. A large amount of muddy
water flooded the PHENIX Interaction Region (IR)where all of the MUID panels were installed. All of
the water receded the following day, it was observedthat the water level had reached about 10 em above
the bottoms of the lower MUID panels. In the following paragraphs, we describe how we recovered thedetector following this disaster.
We partially opened one MUID panel and inspected
the internal parts. The flood line reached the electronics boards which contain the preamplifier and the highvoltage distributor. However it did not reach the lower
end of the larroci tubes, indicating that the chamber
vol ume was not soaked in water. Holes, 6 mm in diameter, were drilled on the side of the bottom rails inorder to drain the trapped muddy water. After mostof the water was drained, nitrogen gas was introduced
into the secondary volumes, which contain the tubes
and the electronics, to dry them out until we finishedchecking all the soaked panels. The electric connec*1
*2

*3

*4

166

Ork Ridge National Laboratory, USA
Interphysica, Russia
University of Tennessee, USA
China Institute of Atomic Energy, China

tors, which serve as the interface between the MUID
panels and external electronics, were cleaned with alcohol. The expected resistance between the terminals of
the low- and high-voltage lines was confirmed before
applying the operation voltages. Pure CO 2 gas wasthen introduced into the chamber volume. The highvoltage was applied after flow the gas for three volume
exchanges. Then, the signal shapes from each tube
were checked using an oscilloscope. The signal rates,
which are the incidences of cosmic rays, were measured. These data were compared with those whichwere taken before the disaster . The details of thechecking procedure are described in Ref. 4. All thepanel tests were completed on Feb. 2, 1999. Two HVchannels were found to be newly sparking under thenormal operation voltages. We expect that they will
recover with further conditioning.
The mud, which was carried along with the water,
still remains in the secondary volumes. It cannot be
removed since most of the panels are buried in between
absorber steel plates, and the secondary volumes of thepanels are inaccessible.
To prevent future flooding, permanent drain pumps
were set up in the IR and the landscape around the IR
was altered to minimize the possible water flow into
the IR.
Next, we describe the gas system design and construction. The outstanding requirements of the MUID
gas system are as follows.
(1) Large volume of gas (50 m 3) and high flow rate
(17 l/min).
(2) Large number of segmentations of the gas volume.
(3) Widely scattered locations of the panels in the
PHENIX IR.
(4) Supply of primary gas (pure CO 2, CO 2 -iC 4H lO
mixture which contains a flammable fraction up to
25 percent) and secondary gas (dry air or N 2)'
Figure 1 shows the schematic diagram of our gas system composed of two major parts. One is located in
the IR and the other in the mixing house located outside of the building which contains the IR. The mixing
house contains the gas supply and recirculation system. A large portion of the gas piping is in the IR.
The CO 2 and iC 4H lO gasses are fed to the south
and north arm chambers through the mass flow controllers which regulate the mixing and flow rates. Up
to half of the chamber gas is recirculated through thecompressor and purifier. The remaining portion is exhausted into the atmosphere in a safe manner. The

Mixing
House

Intera ct ion
RegionC02

Purge Go.s
N2 / Dry Air

Fig. 1. Schematic view of the MUID gas system.
gas qualities , which reflect the chamber performance,at the inlet and outlet are periodically monitored by
the analyzers. When the system detects degradationof the gas quality, a warning signal is triggered. If thedegradation is in the fatal level, the system will shut
off the HV supplied to the chambers in order to avoid
catastrophic failure.
The purpose of having the secondary gas flow is
twofold. One is to keep the volume clean and dry.
Another is to dilute and purge any leakage of primary
flammable gas. The leakage rate from the chamber
volume is estimated to be maximum 10 percent of thetotal flow even without catastrophic failure. Nitrogengas is sucked from the secondary volume and periodically monitored for its flammability using the nitrogensniffing system. If the iC 4 H lO fraction in the sucked ni-

trogen exceeds 25 percent of the lowest explosion limit(LEL), the flow of iC 4 H lO , as well as the high-voltage
and low-voltage power, will be shut off.
The analyzers, pressure gauges, flow meters , andsolenoid valves that open/close each gas circuit are remotely controlled by a PC in the mixing house. The
PC maintains the system.
The design of the gas supply system was reviewed
by the RHIC safety committee. The main concern ofthe committee was preventive measures against fire accidents. Parts in the flammable gas flow line and thosevery close to the flammable gas flow line must not provide any possible ignition sources. The time periodrequired for flammability to increase in the secondary
volume due to a cat astrophic leak was estimated. It
takes 70 minutes to reach 25 percent of the LEL. In ourdesign, the nitrogen-sniffing interval for each monitoring point is 30 minutes, so that the system can detect
a leak well before it reaches dangerous levels. The gas
flow indicators monitor the difference between the inlet and outlet flow rates and are able to trigger thewarning signal once leakage is detected. The system isalready under construction. The major pipes between
the mixing house and IR has been completed.
References
1) H. En'yo et al.: RIKEN Accel. Prog. Rep. 30, 34 (1997) .
2) Y. Mao et al.: RIKEN Accel. Prog. Rep. 30, 36 (1997).
3) A. Taketani et al.: RIKEN Accel. Prog. Rep. 31, 172(1998).
4) A. Taketani et al.: RIKEN Accel. Prog. Rep. 32, 50(1999).
5) K. Kurita et al.: RIKEN Accel. Prog. Rep. 32, 32(1999).

167

RIKEN Accel. Prog. Rep. 33 (2000)

High-Energy Beam Test of PHENIX EM Calorimeter at CERN
H. Torii, T. Awes,*l S. Bathe,*2 D. Bucher,*2 H. Buesching,*2 H. En'yo, Y. Goto, K. Imai, M. Ippolitov,*3
E. Kistenev, V. Mexner,*2 U. von Poblotzki,*2 T. Peitzmann,*2 N. Saito, and S. WhiteThe PHENIX experiment at RHIC 1 ) will start soon,
first for heavy-ion physics, and next for spin physics.
In this experiment, an electromagnetic (EM) calorimeter plays an important role in detecting photons andelectrons/positrons. In order to cover topics in bothheavy-ion and spin physics, e.g., thermal photon measurement in heavy-ion physics, and prompt photon, nO
and weak boson measurements in spin physics, the EM
calorimeter needs to cover a wide energy range from a
few hundred MeV to 80 GeV. Spin physics also requires an energy measurement to within 2% accuracy
to measure the cross sections of prompt photons andnO s with less than 10% error, because the cross sections
fall steeply as their energy increases.
The EM calorimeter was originally designed forheavy-ion physics. There are two kinds of calorimetersin the PHENIX detector. One is a lead- scintillator
sampling calorimeter (PbSc) and the other is a lead
glass calorimeter (PbGI). Table 1 shows their basic
parameters. A "supermodule" is composed of 12 x 12
channels for PbSc and 4 x 6 channels for PbGl. The
total EM calorimeter system in the PHENIX detector
consists of these PbSc and PbGI supermodules.
The performance of both calorimeters for accuracy
and resolution of energy measurement, and hadron rejection was measured at BNL/ AGS up to 7 GeV. In
order to measure the performance up to 80 GeV, thehigh-energy beam test was performed at CERN /SPS. 2)
One PbSc supermodule and four PbGI supermodules
were located at the H6 beam line, and all were tested
with electron beams from 6 GeV /e to 80 GeV /e andn+ beams of 40 Ge V / e. In this report , we present the
preliminary results of PbSc.
Figure 1 shows the setup of the beam test. The

Table 1. Basic parameters of the two kinds of PHENIX
EM calorimeters.
Channelcross section(mm 2 )
depth
(mm)
radiation length(Xo)
Moliere radius(mm)
Supermodule
number of channels
Total system
number of channels

*1
*2
*3

168

PbSc

PbGl

52 .5 X 52.5
375
18
rv30

40 X 40
400
14.4
36.8

144 (12 X 12)

24 (4 X 6)

15552

9216

Oak Ridge National Laboratory, USA
Institut fuer Kernphysik, University of Muenster, Germany
Kurchatov Institute, Russia

Om

i

51

i

CERN 5P5;

H6 beam line

movable nld,tf" ..rn
,
i

15m

+

iron block! muon countersFig. 1. Setup of the beam test. Each component is de-scribed in the text.
EM calorimeters were placed on a movable platform toallow change of the position and angle of the incident
beam on the calorimeters. Delay-line wire chambers(DWC) were located just in front of the colorimeters
for measurement of the vertical and horizontal beamincident positions. Incident position dependence of theenergy deposit was measured and corrected using the
DWCs. Two scintillators (S1 and S2) were used as
trigger counters, and two other scintillators were set
behind iron blocks to identify muons in the beams. We
used 10 GeV /e muon data for the channel-by-channel
gain adjustment of each PbSc channel in addition to
the electron-beam data. To correct time-dependent
gain drift, we applied a laser monitoring system to thecalorimeters.
As a result, we obtained the energy resolution for anelectron beam. The result is consistent with the AGS
data. 3) Figure 2 shows all the data points of the energy
resolution measured at AGS and CERN. These points
are fitted and expressed by the formula(IE/ E = 1.9% EB 8.2%/VE,

Resolutlo,; , I

o/~4
12
10

Preliminary••

BNUAGS•CERNISPS

8
6

4

•

•

•

2

Fig. 2. All data points of the energy resolution measurements at AGS and CERN. The fitting result, 1.9% EB
8,2%VE is also shown.

measurement for an electron beam is in progress. In
this test, we can investigate the accuracy of energy
measurement to within a ±2% limit. The major limit
comes from the remaining error of the channel-bychannel gain adjustment. In this limit, we have foundthat PbSc has a 2% accuracy of energy measurementin the energy region between 20 GeV and 80 GeV. At
10 GeV Ie, we observed a shift of the measured energy
larger than 2% of the beam energy. We need to understand the source of this shift, e.g., photo-multipliertube,4) front-end electronics, or accuracy of the beamenergy itself.
In the present analysis stage, PbSc almost satisfies the physics requirements to cover both heavy-ion
physics and spin physics, although we need greater understanding of its behavior. The PbGI data are also
under analysis. We will conclude our analysis for both
PbSc and PbGI before the PHENIX experiment starts.
Referenceswhere EB represents the quadratic sum. We need more
systematic understanding of the correlatoin between
the AGS data and the CERN data.
An analysis of the accuracy of the energy

1) Y. Batygin et al.: RIKEN Accel. Prog. Rep. 32, 44(1999).
2) Y. Goto et al.: RIKEN Accel. Prog. Rep. 32, 47 (1999).
3) A. Bazilevsky: private communication.
4) G. David et al.: IEEE Trans. Nucl. Sci. 42, 306 (1995).

169

RIKEN Accel. Prog. Rep. 33 (2000)

Feasibility Test of Proton-Carbon CNI Polarimeter for RHIC
1. Alekseev,*1 M. Bai,*2 B. Bassalleck,*3 G. Bunce,*2 A. Deshpande,*4 J. Doskow,*5 S. Eilerts,*3 D. E. Fields,*3
Y. Goto, H. Huang,*2 V. Hughes, *4 K. Imai , M. Ishihara, V. Kanavets, *1 K. Kurita, K. Kwiatkowski, *5
B. Lewis,*3 B. Lozowski,*5 Y. Makdisi,*2 H. O. Meyer,*5 M. Nakamura, B. Przewoski,*5 T. Rinckel,*5
T. Roser,*2 A. Rusek,*2 N. Saito, B. Smith,*3 D. Svirida,*l M. Syphers,*2 A. Taketani,
T. L. Thomas ,*3 J. Tojo, D. Underwood,*6 D. Wolfe,*3 K. Yamamoto,*7 and L. Zhu*7
At Brookhaven National Laboratory (BNL) construction of helical dipole magnets for accelerationof polarized proton beams in RHIC rings is underway. Successful commissioning of the helical dipole
magnets (what we call "Siberian Snakes") will enable
us to do experiments with polarized protons up to
JS = 500 GeV in collider mode for the first time. In
the commissioning phase of the polarized proton acceleration, a reliable polarimeter is crucially required. It
was proposed in 1997 to use proton-carbon elastic scattering in the Coulomb-nuclear interference (CNI) region for the polarimeter. 1 ,2) This polarimeter is called
the "pC CNI polarimeter". In the CNI region, wherea range of momentum transfer squared t (GeV le)2 is
10- 3 < -t < 10- 2, the theoretically predicted analyzing power AN (t )3,4) has the maximum value of about
4% at -t = 2.3 x 10- 3 (GeV le)2 and decreases as - t
increases. This polarimetry has the following advantages: (1) the reaction mechanism is theoretically wellunderstood , (2) the analyzing power weakly depends
on beam energy and (3) its figure of merit is large owing to the large cross section.
Experiment BNL-AGS E950 was proposed in August 1998 to test the feasibility of the pC CNI polarimeter for RHIC using a polarized proton beam at
the AGS. Our goals are to measure the pC CNI analyzing power AN(t) for the first time at the RHIC injection energy and to test experimental devices at the
AGS environment. The challenge is in detecting elastic
pC scattering in a high background and noise environment inside the AGS ring. The proposed method of
identifying pC scattering is detecting only recoil carbons , because the scattering angle of the incident protons in the CNI region is too small to detect. These
recoil carbons have a very low energy, ranging from100 ke V to a few Me V, and recoil angles are almost
90 degrees with respect to the beam direction. The
experimental setup, consisting of a carbon target anddetector arms, is schematically shown in Fig. 1. The
entire setup was installed in the AGS ring. The target
was a "microribbon carbon target" which had been
*1

*2
*3
*4

*5

*6
*7

170

Institute of Theoretical and Experimental Physics , Russia
Brookhaven National Laboratory, USA
Department of Physics and Astronomy, University of New
Mexico , USA
Department of Physics, Yale University, USA
Indiana University Cyclotron Facility, USA
Argonne National Laboratory, USA
Department of Physics , Kyoto University

Sl~~~~Q~¥~bQn )J~I~

Ace. Grid
Electrostatic Mirror I

o

I
13

I
25cm

Fig. 1. Schematic layout of the experimental setup (horizontal view upstream of the target).

developed at IUCF 5). It was 6 f-Lm wide, 4 f-Lg/cm 2
thick and 3 cm long. This extremely thin target makes
it possible to extend its lifetime by reduction of theheating, to suppress the blowup of the beam emittance and to decrease energy loss and multiple scattering of recoil carbons in the target. The silicon strip
detector (SSD) had a thickness of 400 f-Lm and wassegmented into six strips. Each strip was 4 mm wide
and 10 mm long. The surface of the SSD had a special feature of markedly thin Boron implantation withsmall aluminum wire electrodes so that low-energy recoil carbons could penetrate the surface without being
hindered by the electrodes. The micro channel plate(MCP) assembly, consisting of two layers of MCPs anda single anode , had a sensitive area of 27 mm in diameter. It detected secondary electrons emitted from a
5-f-Lg/cm 2-thin carbon foil primarily by the passage ofrecoil carbons. The secondary electrons were accelerated and reflected toward the MCP by both an accelerating grid and an electrostatic mirror. The system ineach arm provides the measurements of energy, timeof-flight (TOF) between the MCP and the SSD andparticle emission angle to the beam direction event by
event.
The experiment was carried out in March 1999. The
proton beam transversely polarized in the vertical direction was accelerated to 21.7 GeV Ie. The polarization sign was flipped each spill in order to reduce systematic errors. The polarization measured by the AGS
internal polarimeter was about 40%. The beam had abunch structure of 4-6 x 109 protons per bunch with awidth of 6 ns and a crossing frequency of 370 kHz. The
trigger was a coincidence between signals from any of
the SSD strips and a beam pulse (RF) from the AGS.
The trigger rate was about 2 x 10 3 per spill. ADCs and
TDCs of all detectors were obtained with the ADC gate
and the TDC start which were generated by the RF.

300
.""

0.01

250
0.008

i

=0.006

200
'Y'
Q,I

=-

~50
.9
E-t

lO.004+0.002 ~

100

°0~~~~2~~~4~~~6~~

Time bin50°0

250 500 750 1000
ADC(ch)250 500 750 1000

Fig. 3. Preliminary result of the raw asymmetry as a function of time bin on arrival time from the target to theSSD. The error bars are statistical only.

ADC(ch)Fig. 2. On-line histograms taken from one of the SSD
strips. The left histogram was obtained without the
microribbon carbon target whereas the right one wasobtained with the target.

The polarization sign and the beam intensity were provided from the AGS. To demonstrate the performanceof our detectors , two on-line histograms obtained fromone of the SSD strips are shown in Fig. 2. The vertical axis is the timing information obtained from the
TDC value and the horizontal axis is the ADC value.
The left histogram was obtained without the taro-etb
whereas the right one was obtained with the target.
Signals from recoil carbons are clearly seen in the righthistogram.
Off-line data analysis is still under way but preliminary results are reported in this article. The strong
correlation between ADC and TDC values of the SSD
in the right histogram in Fig. 2 was noted and thevalues were used to select recoil carbon events. Theenergy calibration of the SSD was carried out by measuring the energy deposition of 5.48 MeV a particles
from an 24 1 Am source. The calibration of arrival timefrom the target to the SSD was performed as follows :(1) TDC data of the SSD are found to be dependent
on the pulse height (slewing e~ect). The dependence
was corrected with recoil carbon kinematics using theenergy value and TOF between the MCP and the SSD.
(2) Time-zero of the arrival time was calculated using
the energy value and recoil carbon kinematics. Aftercalibration procedures (1) and (2) , the time resolution
was defined by the deviation from the center of the carbon locus on the arrival time vs energy plot. The obtained values were 7.3-9.1 ns on each SSD strip. These
values were consistent with the width of the AGS beam
bunch. To study - t dependence of raw asymmetry, a
10 ns time bin was defined on the arrival time vs energy plot. Raw asymmetries in each time bin were

calculated using a so-called square root formula:

JNI· NA - JNt . Nk

Araw = ~r======-~r======JNI· NA + JNt . Nk'(1)

Nl(NA)

where
indicates the number of events inthe left (right) recoil arm with beam polarization up(down) . The result of the raw asymmetry as a function of time bin is shown in Fig. 3. The error bars
are statistical only. - t is a decreasing function of thetime bin number; therefore, the measured raw asymmetry decreases as -t increases. The trend in time bin
dependence of the raw asymmetry is consistent withthe theory. Further analysis will be conducted to derive the pC CNI analyzing power AN(t) from the raw
asymmetry and the beam polarization data of the AGS
internal polarimeter. We will estimate physics backgrounds which could affect the raw asymmetry andcalculate possible systematic errors from them.
In summary, the feasibility of a pC CNI polarimeter
was tested using a 21. 7 GeV / c polarized proton beamin the AGS environment. Low-energy recoil carbons
were detected inside the AGS ring. The preliminary
result of the raw asymmetry revealed the behavior as
the theory predicts. Based on the success of this experiment, a pC CNI polarimeter for RHIC is underconstruction at BNL.
References
1) Proc. Workshop on Hadron Spin-Flip at RHIC Energies ,Vol. 3, RIKEN BNL Research Center, July 21-Aug. 22,
edited by T . D . Lee (1997).
2) J. Tojo et al.: . RIKEN Accel. Prog. Pep. 32, 52 (1999).
3) B. Kopeliovich: High-Energy Polarimetry at RHIC ,hep-phj9801414.
4) N. H. Buttimore: AlP Conf. Proc., No. 95, p. 634(1983) .
5) W. R. Lozowski and J . D. Hudson: Nucl. lnstrum.
Methods Phys . Res. A 303, 34 (1991).

171

RIKEN Accel. Prog. Rep. 33 (2000)

PHENIX Computing Center in Japan (CC-J)
T . Ichihara, Y. Watanabe , N. Hayashi, S. Sawada, S. Yokkaichi,
A. Taketani, Y. Goto, H. En'yo, and H. Hamagaki
The RHIC experiment is scheduled to start in early
2000. To ensure prompt physics output, we havebeen preparing to construct the PHENIX Computing
Center in Japan (CC-J).1 ,2) R&D for CC-J started in1998 at the RIKEN BNL Research Center (RBRC).
The construction of CC-J at the RIKEN Wako
campus , which will extend over a three year period,
began in April 1999. CC-J is intended as the principlesite of computing for PHENIX simulation, a regional
PHENIX Asian computing center , and as a centerfor the analysis of RHIC spin physics. The planned
computing capacity will be sufficient to meet the bulkof the simulation needs of PHENIX. By providing
a vital source of regional computing, CC-J will also
encourage collaborators from China, Korea, India andJapan to be actively involved in analysis of PHENIX
physics data. These capabilities of CC-J are in accord
with the research plans of RIKEN and RBRC, which
initiated the RHIC spin program and which plan
to expand their involvement in the entire PHENIX

program.
Figure 1 shows the concept of the CC-J system.
During the RHIC experiment, data acquisition, andraw data recording and monitoring will be performedat the RHIC Computing Facility (RCF) located at
the BNL. After the track reconstruction, the datasummary tapes (DST) will be produced, duplicatedand exported to the CC-J. Data mining will be carriedout at CC-J as well as at RCF from the DST to
produce micro-DST, filtered by the physics interest.
Simulation for the PHENIX experiments will be
performed at CC-J and this output will be exported
to RCF. Table 1 shows the planned size of CC-J.
Table 1.
CPU (SPECint95)
Tape Storage (TB)
Disk Storage (TB)
Tape I/O (MB/s)

Dec . 1999
2400
100

2.0
45

PHENIX Computing Center In Japan
current config .

updated on 14 Jan. 2000

SUN E450

Main
Camp.
Bldg.

supercomputer
ACSLS

Fig. 1. Concept of the CC-J system.

172

Dec. 2000
5900
100
10
90

Dec. 2000
10700
100
15

112

I

Duplicating Facility

PHENIX CC -J

importDST

Export
Sim.

I

!lOST
sim.

Fig. 2. Configuration of the CC-J system.

Figure 2 shows the configuration of the current CCJ system. A high performance storage system (HPSS)
was installed in early 1999 as a hierarchical storage
system. The HPSS consists of five nodes of an RS6000/SP2 server, a cache disk of 720 GB, four RedWood tape drivers, and a tape robotic storage of
100 TB. A transfer rate of greater than 50 MB/s has
been obtained by parallel ftp (pftp) between HPSSclients and HPSS servers over the Gigabit Ethernet.
The test of date exchange between CC-J and RCF using the SD3 tape cartridge has been carried out successfully.
Linux pc's with Intel Pentium II/III processors areused for the CPU farms. Each node is equipped witha dual CPU, 512 MB of memory and a 14- 18 GB
local disk. Portable batch system (PBS) are used forthe batch queueing. The multi router traffic grapher(MRTG) is used for monitoring the network traffic,

CPU load and free memory. The wide network bandwidth between CC-J and RCF has been achieved by
the Asia-Pacific Advanced Network (APAN). The filetransfer performance of 600 kB/s has been obtainedusing the large TCP window-size of 256 kB. This enables us to synchronize the data base between CC-J
and RCF.
Stress tests for the entire system were carried out
successfully in May, July and December 1999. During the tests, the physics simulation outputs were obtained. We plan to start the operation of CC-J in
April 2000.
References
1) http://ccjsun.riken.go.jp/ccj
2) Y. Watanabe and T. Ichihara: RIKEN Accel. Prog.
Rep. 32, 53 (1999).

173

RIKEN Accel. Prog. Rep . 33 (2000)

A Workstation Farm Optimized for Monte Carlo Shell Model
Calculations: Alphleet
Y. Watanabe, N. Shimizu, S. Haruyama, M. Honma, T. Mizusaki, A. Taketani, Y. Utsuno, and T. Otsuka
We have built a workstation farm named "Alphleet",which consists of 140 COMPAQ Alpha 21264 CPUs,
for Monte Carlo Shell Model (MCSM) calculations. It
has achieved a more than 90% scalable performancewith 140 CPUs when performing the MCSM calculations using PVM (Parallel Virtual Machine) libraryand 61.2 Gflops of LINPACK benchmark application .
We have proposed and developed the Quantum
Monte Carlo Diagonalization (QMCD) method forsolving the many-body problem with a two-bodyinteraction. 1- 4 ) In the QMCD, the most important basis vectors of the many- body Hilbert space are searched
for stochastically, and the Hamiltonian is diagonalizedwith respect to them. Contrary to the conventional
Quantum Monte Carlo (QMC) methods, the minus
sign problem is absent, and energy eigenvalues, matrix elements and wave functions can be 0 btained not
only for the ground but also the excited states. In
the nuclear shell model, the matrix of the Hamiltonianis diagonalized for a given many-body system whereparticles are interacting through a two-body system.
The dimensions of the Hamiltonian matrix are often
too large to carry out the conventional exact diagonalization . On the other hand , the shell model calculations play an indispensable role in going beyond mean
field approximations. Thus, an alternative approachis needed in order to solve the shell model. The shellmodel calculations based on the QMCD are referred toas the Monte Carlo Shell Model (MCSM).
The MCSM is found to be extremely useful for understanding the nuclear shell model, particularly forlarge systems. Such large systems are of particular significance in the study of nuclei far from the stabilityline which are being explored by means of radioactive
nuclear beams. The MCSM calculation is characterized as the importance truncation to the full exact diagonalization of the Hamiltonian matrix,S) because it
produces a good approximation with a small number(about several tens) of optimally selected importantbasis vectors .
In the QMCD calculation, it takes almost all the
CPU time to calculate each Hamiltonian matrix element with many trial basis vectors to determine the(nearly) optimal transformation. This characteristic issuitable for implementation in a parallel calculation using many CPUs , particularly in a loosely coupled system because the calculation of each matrix element canbe divided into individual segments which can be processed in parallel without interacting with each other.
We decided to develop a computer system known as
a "cluster" or "farm" because of the absence of a com-174

mercially available computer system which realizes thissimple parallelism. Every parallel computer available
on the market is extremely sophisticated and too costly
for our purpose. The performance of floating point
calculations is also crucial. However vector CPU s are
not suitable for our calculation because our calculation
does not produce long enough vector which make vector CPUs work efficiently. We chose the Alpha 21264
which has the highest floating point calculation performance (58 .7 SPECfp95 at 500 MHz) in scaler CPUs.
It is about fourfold faster than most popular CPUs in
the commodity market.
The workstation farm that we have built is named"Alphleet" , which consists of many "Alpha" CPUs ina "Fleet" . Figures 1 and 2 show a schematic diagram
and a photograph (half nodes) of the Alphleet, respectively. The Alphleet consists of 71 COMPAQ DS20 s(a server and 70 clients) connected to each other via
a high speed network. Each client has two Alpha21264 CPUs (500 MHz) , 512 MB of memory, Myrinet 6 )and 100 BASE-T network interfaces but no hard disks.
On the contrary, the server which also functions as
a firewall, is well equipped with UPS, 36 GB Disk,
Myrinet and four 100 BASE-T network interfaces, but
only one CPU and 256 MB of memory. Three NFS
groups divided by the 100 BASE-T interfaces of theserver (Fig. 1) may relieve the network congestion of
NFS. Each client node power supply is connected to a
power controller, which enables us to switch the powerof each node on/off remotely from the server.
1.28 Gbps + 1.28 Gbps

Alphleet Configuration

IOOMbps

L...-~------,x70

RlKENintranel

ServerFig. 1. Schematic diagram of the Alphleet: The Alphleet
consists of 71 COMPAQ DS20 s (a server and 70 clients)
connected by both Myrinet 6 ) and 100 BASE-T to eachother. Each client node power supply is connected to a
power controller, which enables us to switch t he powerof each node on/off remotely from the server.

•
•
•
c.:i

•

Q)

~
Q)

E

50

::e

50

0~-1~
6--3~2--~~6~4~--~~--1~278~

Number of CPU

Fig. 2. The Alphleet: This photograph shows the serverand half client nodes of the Alphleet.

It is our goal for this system to maximize performance for the MCSM calculation and to minimize
management tasks. The latter is desired to enable easy
management of such a large scale system for nonprofessional computer users. Therefore, we decided to design a diskless configuration for clients. We will havealmost no reason to service to these clients if they do
not have hard disks which are very costly but fragile. This means that each client must be booted up by
the server through the network. The power controllers
prevent the server from overloading when booting up
the entire system by automatically supplying power toeach client at 30 sec intervals. Thus the entire system can be booted up within about 40 min. without
any difficulties. Moreover, the diskless configuration
enables the power to each client node to be switched
off with no risk at any time. This feature also enables
power to be recycled for each client node from a remotesite using power controllers, even if a client has hungup without any response. The lack of local swap space
is another difficulty associated with a diskless configuration. Therefore, we added 512 MB memory to eachclient which is estimated to be sufficient for the MCSM
calculation. This approach should be worthwhile forother single purpose computer systems for which thememory consumption can be estimated.
Each node has two types of network interfaces; oneis the 100 BASE-T for NFS, also used for booting up,
and the other is Myrinet, used only for interprocess
communications, which is a 1.28 Gbps + 1.28 Gbps
duplex switched network. Because of the Myrinet, theAlphleet achieved a 93% scalable performance when

Fig. 3. Scalability of the Alphleet parallel calculation:
Filled circles represent measured calculation time of
MCSM as a function of number of CPUs. Solid line isa guide for the eyes showing complete scalability. The
Alphleet shows a more than 90% scalable performanceeven with 140 CPUs.

performing the MCSM calculations, with 140 CPUs
(Fig. 3). In addition, the Alphleet also achieved the61.2 Gflops LINPACK benchmark without any precise tuning. It was ranked 169th on the "14 th TOP
500 List,,7) for the world's fastest computer systems,
published in November 1999.
The Alphleet, which consists of many ready-madecomponents, has achieved superior performance without presenting management difficulties. We demonstrate one sample system which has the advantage ofbeing a single purpose system, in this report. On theother hand, we would like to mention that this technique as a "farm" is useful not only for parallel computing for a few users but also for a more general multipurpose, multiuser system, because job independence ofeach user should be offered by a loosely-coupled multiCPU system.
References
1) M. Bonma, T. Mizusaki, and T. Otsuka.: Phys. Rev.
Lett. 75, 1284 (1995).
2) T. Mizusaki, M. Bonma, and T. Otsuka.: Phys. Rev. C
53, 2786 (1996).
3) M. Bonma, T. Mizusaki, and T . Otsuka.: Phys. Rev.
Lett. 77, 3315 (1996).
4) T. Otsuka, M. Bonma, and T. Mizusaki.: Phys. Rev.
Lett. 81, 1588 (1998).
5) T. Otsuka, T. Mizusaki, and M. Bonma.: J. Phys. G
25, 699 (1999).
6) http://www.myri.com/
7) http://www.top500.org/

175

RIKEN Accel. Prog. Rep. 33 (2000)

Development of High-Rate MUSICK. Kimura, T. Kato, T. Ohtsubo, A. Ozawa, T. Suzuki, I. Tanihata, and Y . Yamaguchi
At the forthcoming RI beam factory, the high rateparticle identification system is expected to be very
useful for the experiments using radioactive secondary
beams. We have thus constructed a new type ofmultiple sampling ionization chamber (MUSIC) which
can be used stably with high-intensity beams, andtested it by measuring projectile fragments of 40 Ar at
E j A = 92 Me V for comparison with the normal type ofMUSIC which we had developed previously. The newhigh-rate MUSIC (HR-MUSIC) has a simple construction as shown in Fig. 1. It consists of multiple anodes
and cathodes made of thin foil (4 J.tm thick mylar aluminized on both sides) tilted by 30° toward the center
axis. Eight layers of anode and cathode pairs, each separated by a 20 mm space, are stacked together. Thus ,the effective length of the HR-MUSIC is 16 cm. The
counter was operated using P-10 gas at the pressure of
740 Torr.
Four anode signals were separately amplified using the conventional charge sensitive preamplifier andspectroscopic amplifier systems. Since this IC has no
grid , both electrons and slowly moving positive ionscontribute to anode signals. Slow positive ion tails
could be completely rejected using bipolar signals fromthe spectroscopic amplifier.
Energy loss of the projectile fragments was measured
by the HR-MUSIC and the ordinary MUSIC sharing
common gas, located in tandem at the fragment separator course of RIKEN (RIPS). The latter MUSIC isa gridded ionization chamber having five anode pads,

mylar window (50 I1mx60 4»

Fig. 1. High-rate multiple sampling ionization chamber(HR-MUSIC).

176

0.5 r - - - - - r - - - - - r - - . . , . - - - - - r - - - r - - - - - ,

0.4

c

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~

::J

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oC/)

Q)
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N

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/1.'/

¥.. '

0.1

•

HR-MUSIC- - &:=0.817t ·1/2 +0.027
A

MUSIC

....... &:=0.815t ·1/2 +0.022
0.0 L...-_-'--_--'-_---'_ _.l-_.....L.-_---J
0.0
0.1
0.2
0.3
0.4
0.5
0.6

t

·1/2

(em

-1/2

)

Fig. 2. Z-resolutions of MUSIC and HR-MUSIC as a function of gas thickness t in cm.

whose total length is 50 cm. From the energy loss spectra for AjZ = 2 particles, we obtained Z-resolutions,defined as twice the FWHM of a Z - peak divided by
the difference of peak channels for Z + 1 and Z - 1.
Figure 2 shows the Z-resolutions of the two MUSICs
for Z = 14 as a function of t- 1 / 2 , where t is gas thickness in cm. They were obtained by plotting the energy
loss spectra for the average of various numbers of themultiple anode signals. Z-resolutions of the two MUSICs fall on a straight line. This dependence indicatesthat the resolutions are almost entirely determined by
the straggling of the energy loss. Contributions fromother effects like electronic noise are represented by theoffset of the straight line, about 0.02.
As for the rate dependence of Z-resolutions, we haveinvestigated it under various fragment intensities from
0.4 kcps to 60 kcps and no significant dependence wasfound. In order to obtain higher rate capabilities of the
HR-MUSIC, we have further tested it under higher intensities using a primary 40 Ar beam. It was found thatthe resolution remains constant up to about 100 kcps
and it deteriorates gradually above that. A pileup of
the anode pulses appears to be mostly responsible forthis effect and not the intrinsic detector performance.

RIKEN Accel. Prog. Rep . 33 (2000)

Calibration of Heavy Ion Telescope on Board MDS-l Satellitewith 40 Ar Beam
H. Matsumoto, H. Koshiishi, T. Goka, H. Katoh, and H. Miyasaka
The satellite MDS-1 will be launched into geostationary transfer orbit in 2001 from Tanegashima spacecenter. A heavy ion Telescope (HIT) will be on board
this satellite to observe galactic cosmic rays. The geometric factor of the HIT is rv25 cm 2 ·sr and the observable energy range is, e.g., 11- 83 MeV/nucleon foroxygen.
An 40 Ar beam with an energy of 95 MeV/nucleon
was irradiated to examine the particle identification
ability of the HIT. The irradiation test was carriedout at the E3 of the ring cyclotron of the Institute of Physical and Chemical Research. The energy resolution was tested at four different energies
by placing Al moderators of different thickness before in front of the HIT. In the charge discrimination test the secondary particles produced by the nuclear reaction of the 40 Ar beam with acrylic were
measured.
Figure 1 shows the test configuration with a cross-

4O:rOd~ratl At rl:-~~D:2 PINH6

sectional view of the telescope. The HIT consists of
two position sensitive detectors (PDS) and sixteen PIN
type detectors. The PSD1 has a 62 mm x 62 mm
effective area with a 0.2 mm thickness , PSD2 has a
62 mm x 62 mm effective area with a 0.4 mm thickness
and the PIN type detectors have an 85 mm-diametercircular effective area and a 0.42 mm thickness. The
telescope is optically shielded by 0.7 mm-thick aluminum foil.
As a result of the energy resolution test, the peakloss energy of each detector comes within 5% of thetheoretical value, and the full-width at half maximum
is also about 5%.
In the charge discrimination test, nuclear fragmentation from helium to oxygen were measured. Figure 2
shows the histograms of atomic number resolution obtained by the .6.E-E method. This result undicatesthat the isotope discrimination ability of the HIT isabout 0.5 amu (FWHM).

Acrylic Fragment IHIT I---+~ ~

95MeV/nuc

...

U--

4°Ar
95MeV/nuc10m" 62mm'b) Charge discrimination testa) Energy resolution test

Fig. 1. Cross-sectional view of the telescope and the beam arrangement.

FWHM=O.34amu

U
FWHM=O.55amu

2

5

He

3

4

mass_number

6

7

mass_number

6

Be

B

FWHM=O.38amu

FWHM=O.41 amu

7

8 9 10mass_number

9 10 11
mass_number

C
FWHM=O.53amu

10 11 12 13 14
mass_numberNo

FWHM=0.47amu

FWHM=O.40amu

13 14 15
masA_number

14

15 16 17 18
mass_number

Fig. 2. The atomic number histograms.

177

RIKEN Accel. Prog. Rep. 33 (2000)

Beam Calibration of Fiber Neutron Monitor onboard the Exposed
Facility of the Japanese Experimental Module
K. Koga, T. Goka, H. Matsumoto, H. Kato, H. Miyasaka, and Y. Muraki*
A new type of neutron detector, the FIB (FIBer neutron monitor), is under development at NASDA (National Space Development Agency of Japan). The FIB
uses scintillation fibers and multianode PMTs (photomultiplier tubes). It measures the high-energy neutrons, such as those of solar origin and albedo neutrons, in the energy range from 15 MeV to 100 MeV.
The main applications of this detector are to informthe cosmonauts of the arrival of strongly charged particle radiation, and to elucidate the ion acceleration
mechanism at the solar surface. This detector will belaunched in the JEM (Japanese Experimental Module) exposed facility of the ISS (International Space
Station) in the year 2003.
A high-energy neutron undergoes elastic collision
with a hydrogen atom in the scintillator and produces
a recoil proton. Since the produced recoil proton penetrates two or more scintillators, the energy of an incident neutron can be determined by measuring thepath length and the trajectory of the recoil proton using 512 ch outputs of the scintillators which are placedin the two orthogonal directions, X and Y, if only theincident direction of a neutron, e.g., a neutron of solar origin, is known. The light emitted by the scintillator is transported by 15- 20 cm-Iong optical fibers
to the PMT. Hamamatsu H4140-20 photomultipliertubes are used as the multianode (256 ch) photomultiplier tubes in the X and Y directions. The signals
from the two PMTs are sent to the electronic equipment, which consists of a charge amplifier, an analog memory and a data-processing board. The circuit
was designed using CMOS circuits by the KEK (High
Energy Accelerator Research Organization) advanced
technology group. Figure 1 shows the structure of the
FIB. Figure 2 shows a picture of the FIB sensor.
The EM (engineering model) of this FIB was investigated using an accelerated beam. The EM is devoid of the problems of crosstalk and anticoincidence
experienced by the BBM (bread board model). The
hydrogen molecular ion beam bombards the sensor after passing through aluminum plates of different thicknesses. Figure 3 shows the irradiation test conditions.
Beam Energy: 120 MeV (Ht)Beam Intensity: 1 x 103 -1 X 106 p/sec.
Moderator: 0, 5, 10, 15, 20, 30, 60 mm (Aluminum)
We used aluminum plates (0-60 mm thickness) as
both the moderator and the target to obtain a mixed
source of protons and neutrons of different energies.
The following issues were investigated in this test:
Solar-Terrestrial Environment Laboratory, Nagoya University

178

Anti-PMT

256ch
Multianode
PMT
Fig. 1. Structure of the FIB.

Fig. 2. Picture of the FIB sensor.

(1) Energy calibration(2) Crosstalk between fibers(3) Discrimination of neutrons from protons(4) Performance of anticoincidence
Figure 4 shows actually obtained typical tracks inthe sensor. From these tracks, we can distinguish between neutrons and protons. The track of the proton
started from the first layer of the fiber and advanced in
the incidence direction. The track of the proton thatwas recoiled from the neutron started from the optional
layer and proceeded at an angle from the incidence direction. The crosstalk between fibers decreased further
in the EM than in the BBM. In the case of the BBM,
the track was spread out more than three pixels aroundthe exact track. The main modifications to the EM toreduce crosstalk were the shading of each fiber using
an aluminum evaporation film, the end-face processing of fibers for use as the reflector and the integrated
shaping of the light-guide.

Scintillator

Aluminum plates

Scintillatoro· ·1· ·111 B Be; cOp, nFig. 3. Irradiation test conditions.

Table 1 shows the energy resolution for protons fromthe anode and the dynode-sum of a 256 ch PMT. For
protons with the energy of 96.84 MeV, the energy resolution is 63% from the anode output and 30% fromthe dynode-sum output. The realization of an energy
resolution in the range better than that for the anode or dynode-sum is under investigation. The performance of anticoincidence is confirmed. The rate of
unexpected defeat of protons is from 0.004 to 0.02% .
From irradiation tests of the EM, the performanceof the FIB is confirmed. However, there remains some

Table 1. Energy resolution.

The incident
energy (Me V)

33.69
48.80
60.86
71.29
80.68
96.84

Energy resolution Energy
from output of resolution from
outputofanode.
(FWHM:MeV)
dynode-sum(FWHM:MeV)
15.82
9.48
9.98
17.16
8.65
17.95
9.52
14.80
8.78
14.69
18.64
22.68

crosstalk which is caused by the joint between thefibers and the PMT. This problem should be solved
before construction of the FM (flight model). Except
for this problem, it was almost possible to complete thedesign of the FM. Manufacture of the FM of the FIB
will be started in 2000 and it will launched in 2003.
References
1) I. Imaida et al.: Nucl. Instrum. Methods Phys. Res. A
421, 99 (1999).
Fig. 4. Actually obtained typical tracks in the sensor.

179

RIKEN Accel. Prog. Rep. 33 (2000)

RF Ion-Guide System for Trapping Energetic Radioactive
Nuclear Ions from Fragment Separators
M. Wada, 1. Katayama, S. Okada, K. Okada, K. Noda,*l H. Kawakami,*2 and S. Ohtani
The projectile fragment separator provides a wide
variety of radioactive nuclear ions without any restrictions on chemical property or lifetime limit of the ions,which are unavoidable problems in the ordinary ionsource-based ISOL (isotope separator on-line) facilities. The beam energy and quality in terms of thelongitudinal and transverse emittance is, however, notadequate for low-energy beam experiments, in particular for trapping experiments.
We have proposed a new scheme to provide
low-energy high-quality beams from such fragment
separators. 1 ,2) The system is comprised of a primarydegrader, a large He gas cell and a beam guide. The degrader reduces the beam energy to about 5 MeV lu. If
the primary energy of a beam is 100 MeV I u, more than
50% is in the energy range of 0 to 5 MeV I u after passing through a degrader foil of suitable thickness. The
medium energy beam thus obtained is then injected
into the He gas cell. In order to stop the 5 MeV I u
beams, the cell is required to be 2 m in thickness with
0.2 atm of He . The thermalized ions should be extracted from the exit of the cell and then guided toa high vacuum region by the RF sextupole ion beam
guide (SPIG) through multiple skimmers. 3 ,4)The main part of the system is the He gas cell. The
system is based on the same principle as that of theion guide ISOL (IGISOL), but a significant difference
is in the cell size. In the ordinary IGISOL, a typical cell

Hegas

size is 1 cm which corresponds to a stopping capabilityof 10 keY lu. This limits the effective thickness of thetarget and the corresponding yield. The reason a small
cell size is used in the IGISOL is that the transport ofthe ions in the cell is performed only by the gas flow.
If a large cell were used in the ordinary IGISOL, it
would take many minutes to extract ions which would
cause severe loss of ions due not only to the lifetime
limit but also to other processes such as neutralizationand diffusion. In the proposed system, on the other
hand, ions in the cell are totally under the control ofan electric field. Many ring electrodes are placed in
the cell, which produces a superposition of a DC field
and an RF field (RF ion guide). The DC field gives
the ions a relatively high velocity in order to quickly
exit the cell and the RF field focuses the ion beam tothe small exit hole. This allows the use of a large-size
gas cell and a small exit hole.
Numerical simulations were performed for the RF
ion-guide system. A single ion motion in the electric field was traced by the Runge-Kutta integration
method. The effect of gas collision was taken into account by the Monte Carlo method. The kinematics
of each collision was simulated in two different ways.
In the simpler one, isotropic scattering at the center of the mass system was assumed and the mean

~ PumpF up

oFig. 1. Schematic diagram of an off-line test. A part of
the gas cell which contains 80 ring electrodes with aninterval of 2.5 mm is used for the test. RF and DC
potentials are applied to the ring electrode. Metallicions are produced by irradiation of a pulsed YAG laser
in a small gas cell. Ions from the small cell are guided
by the RF ion guide to a Faraday cup.
*1

*2

180

National Institute for Radiological Science
Institute of Particle and Nuclear Studies, High Energy Accelerator Research Organization

Fig. 2. Preliminary results of an off-line test. Ion current
detected at the Faraday cup is plotted as a function of
RF voltage and DC electric field of the RF ion guide.
Total current was measured at the exit of the small cellfor normalization. He pressure of 20 Torr and maximum
voltage of 125 Vpp were limited by a discharge problem
at the feed through of the present setup.

free path was chosen to emulate the experimental result of the ion mobility in He gas (",20 cm 2 /Vs at
760 Torr). In the more complex one, a classical scattering model in a semi-empirical potential, which was
determined by Mason and Schamp from their mobility measurements ,5) was used. The estimation of thesimulation results is under progress.
A test bench for the RF ion-guide system witha gas cell of 60 cm in length has been constructed
at KEK-Tanashi. The gas throughput is designed
to be 2 Torr l/s which allows the use of turbomolecular pumps and highly pure He gas.
The
entire cell is capable of baking and a gas purification system (SAES Monotorr) is used to prevent
possible losses due to charge exchange with impurities. Off-line tests are under progress using apulsed ion source. In the present test, pulsed metallic ions were produced in the gas cell by irradiation of a

YAG laser and the transported ions were detected bya Faraday cup which is , for the moment , still locatedinside the cell. A schematic diagram of the test setup
is shown in Fig. 1 and preliminary results are shownin Fig. 2.
On-line test experiments are scheduled to be performed at the RIKEN RIPS facility aiming at the laser
spectroscopy experiment of trapped Be isotopes.
References
1) M. Wada et al.: 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) H. Xu et al.: Nucl. Instrum. Methods Phys. Res. A
333, 274 (1993).
4) S. Fujitaka et al.: Nucl. Instrum. Methods Phys. Res.
B 126, 386 (1997).
5) E. A. Mason et al.: Phys. Rev. 112, 445 (1958).

181

RIKEN Accel. Prog. Rep. 33 (2000)

Development of a Polarized Solid Proton Target by Meansof the Integrated Solid Effect (ISE)
M. Hatano, H. Sakai, A. Tamii, T. Uesaka, and T. Wakui
We have recently begun developing a polarized proton target system using a single crystal of naphthalene
doped with pentacene as the target. The protons in
the crystal are polarized by means of the integrated
solid effect (ISE).l-S) The most significant advantageof this method is its applicability at a high temperature(;::: 77 K) and in a low magnetic field (::::; 3 kG).
The target is appropriate for investigating the structure of unstable nuclei via the inverse kinematics
method. In such investigations, it is crucial to be able
to detect low momentum recoil protons to achieve highangular and energy resolutions. The polarized proton
target is also useful in other experiments , for example,
measurement of d + p polarization correlation.
The protons are polarized by repeating the following
processes (Fig. 1) .
. (a) Pentacene molecules are excited to one of higher
singlet states by a pulsed laser beam .
. (b) About 2% of the pentacene molecules de-excite to
the lowest triplet state (To), and have large electron
population differences among the three Zeeman sublevels. This indicates that electrons are polarized.
(c) The polarization of the electrons in the To stateis transferred to the protons by irradiation of a microwave and sweeping of the magnetic field (ISE).
(d) The pentacene molecules de-excite to the groundstate (So).
(e) The proton polarization is transferred to the neighboring protons by the spin-spin interaction.
In process (b), the population differences among thethree Zeeman sublevels are governed by a selection
rule in the transition from singlet excited states to the

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0, --t>76%( C)
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1-1, --t>12%

nonradiative process
radiative process

Fig. 1. Energy levels of pentacene. 5 )

182

12%

1+1,-+>

I

~

!

So

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triplet state, and therefore have little temperature dependence.
The ISE method, in process (c), is a kind of dynamic
nuclear polarization (DNP)l) method. In a low magnetic field, the electron spin resonance (ESR) line of
the electrons in the To state consists of many narrowand independent ESR lines of spin packets.l ,S) By theclassical DNP method, in which a static magnetic field
is applied, the polarization transfer is inefficient in a
low magnetic field due to the destructive contribution
from many spin packets. However , in the ISE method,the external magnetic field is swept through the ESR
line. The polarization is transferred via the following
sequence for each spin packet:

(1)

(3)
After the magnetic field is swept, the polarizationsof electron spin packets are constructively transferredto the protons, even in a low magnetic field.
In process (d), the molecules de-excite to the So statewith a lifetime of 20 f-.Lsec, which is much shorter than
the relaxation time of the electron polarization. Since
the So state is diamagnetic , the proton polarization
is maintained for a long time, even at a temperature
higher than 77 K.
In the actual experiment, we use an Ar+ laser beamwith a wavelength of 514 nm, which is chopped by an
optical chopper with a duty factor of 1.0 x 10- 2 • We
use an NMR system to measure the proton polarization. A C-type magnet, which achieves a homogeneityof 10- 3 in a 3 x 3 x 3 cm3 volume, will be available soonfor practical use. A cavity for 9.3 GHz will be readyfor mounting in the magnet in a few months. We are
now preparing for the manufacturing of single-crystal
samples.
References
1) A. Henstra et al.: Ph. D. thesis, Leiden University(1964).
2) A. Henstra et al.: Chern. Phys. Lett_ 165, 6 (1990).
3) A_ Henstra et al.: Phys. Lett. A 134, 134 (1988).
4) D. J. van den Heuvel: Master's thesis, Leiden University(1991) (unpublished).
5) M. !inuma: Ph. D. thesis, Kyoto University (1997).

· 6. Material Analysis

RIKEN Accel. Prog. Rep. 33 (2000)

Development of a Highly Sensitive High-Resolution In-Air
Particle-Induced X-Ray Emission (PIXE) System: I
K. Maeda, K. Hasegawa,* and H. Hamanaka*
A crystal spectrometer combined with a positionsensitive X-ray detector is demonstrated to be suitable for measuring particle-induced X-ray emission(PIXE) spectra with high energy resolution. Recently,
we developed a compact crystal spectrometer system equipped with a position-sensitive proportionalcounter (PSPC) for a high-resolution PIXE study in
air at atmospheric pressure. 1) The utility of the system
for in situ chemical state analysis was demonstrated
by measuring the Ka and K{3 spectra of third period
elements. 2 ,3) The chemical state analysis was applicable to minor elements down to the order of 0.1 %. The
system requires a small sample amount (0.1-1 mg) , a
small target area (1-10 mm 2 ) and a short measuring
time «1 h) to obtain a spectrum using a moderatebeam current (10-100 nA).
A very low beam current is required for delicate samples. If we intend to use the system for the mappingof chemical states, the measuring time required mustbe significantly reduced. Therefore, we constructeda prototype of a highly sensitive crystal spectrometersystem using a newly developed large-window PSPC 4 )in order to increase the efficiency of X-ray detection by
one order of magnitude.
The experimental setup is almost the same as that
described in previous papers l - 3 ) except for the PSPC.
The large-window PSPC used here is a laboratory
built, resistance anode type (see Fig. 1 (a)). It employs seven carbon fibers of 7 /-lm diameter as anodes.

The sensitive area is 44 mm in width and 52 mm intotal height. The number of effective analyzing channels is 310 x 7.
The block diagram of a signal processor for theseven-anode PSPC is shown in Fig. 1 (b). The sevenanodes operate independently as a single PSPC. Bothends of each anode wire are connected to ' chargesensitive amplifiers (preamplifiers), A and B. After
passing through mixing amplifiers with seven inputs,
MIX AMP A and B, pulses from the seven anodes
are converted into digital signals using a 512 x 7 ch
charge-division analyzer and then stored on a computer. A 512 x 7 ch histogram memory is used for 2D
measurements. The 7 ch memory address lines correspond to the seven anodes. A set of two output pulses,
A and B, of MIX AMP A and B gives informationon the absorbed X-ray position. The selection of oneof seven lines is carried out with a combination of an
ADDER and a 7 ch DISCRIMINATOR. X-rays with
undesirable energies are eliminated by the DISCRIMINATOR. We can simultaneously obtain seven spectra.
As an example of test experiments of rapid measurements, phosphorous Ka spectra (2.0 keV) obtained
from BP powders are shown in Fig. 2 (a). A proton
beam of 2.1 MeV was used for excitation. The proton
beam current was 30 nA and the measuring time
was Is. A Ge(lll) crystal was used as an analyzing
crystal. The conversion of the seven measured spectra
into one spectrum was carried out by software. Each

(a)

(b)

t
t--

60mm ~

8.5mm Mylar 'Mndow
I

Cathode1i 2mm Olvergence Silt
I

I

/ \

Anode

\
CathodeFig. 1. (a) Schematic illustration of the seven-anode PSPC. (b) Block diagram of thesignal processor.
College of Engineering, Hosei University

183

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BP

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250

300

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sum

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~

:.

0

'.

...

:.,

10

~
No.1

30

>OJ .....:

0

20

x

20

10

'.
.... ,'::....j.;;....I.'i:;..

20

.!:.
?: 10

Z; 50

.... ';..

P KP

No.6

..

:1.. "

'" 10

!ic:

c:

IU

.0\.

, _1.'·.i~:~"..

~::..~':.

0

;.,

-'=
..,

(d)

..

. ".-ii:-;:~-. .

20. 1 ••

.r:

20

..

,

10

]

Q=1IlC
No.7

c 20

....

P KP

'

Gi

No.4

E 10

X

10

.I~

10

BP

20

x

~

.s
-=

I

~

~.
:~

.":,;.
.".

::I

,"m

40,

No.5

10

11
~

-,.}.

(e)

~

I ••

10

Q=0.03 IlC

~
No.6

20

P Ka.

J -',
Ka, .•
0~-2-50--de-3~00=~~-3-50~)M~-40~0~

;

30

BP

1::1 "'., '.'.

Q z O.03I1C"...

' "'""- .~ d,_~'l·'·- "'':'
No.2.('-:-~"'-' ... ~_,,'.f-'~"' ,
No.1

20
10
0
150

NO.3

.:::"

....i~
350
300
250
200
PSPC Position (channel number)

200
250
300
350
PSPC Position (channel number)~x
Fig. 2. (a) 7 ch spectra of the P Ka from BP; (b) summed spectra of the P Ka from BP;(c) 7 ch spectra of the P K,6 from BP; (d) summed spectra of the P K,6 from BP; (e)summed spectra of the P K,6 from CaHP0 4 ·2H20. Q is the accumulated projectile
charge.
spectrum has its own offset channel and channel-toposition conversion factor. Figure 2 (b) is the sumof spectra No.1- No.7 after correction of the offset andconversion factors. Here , the correction factors wereobtained by measuring the peak channel of P Kal ,2 atdifferent positions of the PSPC mounted on a sliding
stage for a sufficiently long measuring time.
In order to examine the energy resolution of theseven-anode PSPC spectrometer, the full-width at half
maximums (FWHMs) of the P Kal ,2 lines were measured by a 140 s measurement under the same condition. Line broadening due to aberration of the X-ray
flux was observed on the highest (No.7) and lowest(No.1) anodes. However, the effect of line broadening
on the summed spectrum is not large: The FWHM
of Kal ,2 in the summed spectrum (2.8 eV) is 0.4 eVlarger than that of the previous single-anode PSPC
spectrometer.
Although the K,8 spectra reflect the chemical bonding nature more prominently than the Ka spectra, theproduction cross sections of K,8 X-rays are one or twoorders of magnitude smaller than those of Ka X-rays.
The seven-anode PSPC spectrometer was applied tomeasure the P K,8 spectra (2.1 ke V) of BP. Figure 2(c) is a 7 ch spectra obtained with a 30 s measuring

184

time. The shape of each spectrum is not clear. However, the asymmetric feature of the P K,8 ofBp 2 ) is well
reproduced in the summed spectra shown in Fig. 2 (d).
The K,8 spectrum of P in CaHP0 4 ·2H 2 0 is also shownin Fig. 2 (e). The low-energy satellite peak K,8' , whichis evidence of P -0 bonding, is clearly observed. The
peak-to-background ratio is somewhat poorer thanthat obtained by the previous spectrometer. 2 )The high sensitivity of the crystal spectrometer
combined with a large-window multianode PSPC wasdemonstrated. Further improvements of energy resolution and suppression of background noise are requiredas the next step.
References
1) K. Maeda, K. Hasegawa, H. Hamanaka, and K. Ogiwara: Nucl. Instrum. Methods Phys. Res. B 134, 418(1998).
2) K. Maeda, K. Hasegawa, H. Hamanaka, and M. Maeda:
Nucl. Instrum. Methods Phys. Res. B 136/138 , 994(1998).
3) K. Maeda, A. Tonomura, H. Hamanaka, and K.
Hasegawa: Nucl. Instrum. Methods Phys. Res. B 150,
124 (1999).
4) K. Hasegawa, K. Maeda, S. Nakayama, A. Tonomura,and H. Hamanaka: Int. J. PIXE 8, 47 (1998).

RIKEN Accel. Prog. Rep. 33 (2000)

PIXE Analysis of Lead in the Feather of a Jungle Crow
Living in Tokyo
H. Yoshiki, K. Maeda, A. Tonomura, and H. Higuchi*
Examination of bird feathers is considered to bevaluable for monitoring the environmental pollutionof the bird species' habitat. 1) For evaluation of thepollutants, heavy metals, such as cadmium, lead, andmercury, absorbed by the feathers, are often analyzed
by atomic absorption spectrometry. We demonstrated
that particle-induced X-ray emission (PIXE) was useful for the analysis of heavy metals in feathers without
any pre-treatment. 2) This method enables the analysis of heavy metals in various parts of the feather. In
this report, we describe the PIXE analysis of lead concentrations in different parts of the feather of a jungle
crow living in Tokyo. Moreover, we discuss how leadis excreted from the body to the feather.
A feather of an adult jungle crow ( Corvus
macrorhynchos) was collected from Meguro-ku inTokyo on October 4, 1997. The length of the vanein the feather was approximately 18 cm. The feather
was cleansed with an ultrasonic cleaner in a commercial neutral detergent (Iuchi Seieido Co., Clean Ace S)
for 1 hr, and then thoroughly washed with deionizedwater. The feather was bombarded in air with a 1.6MeV proton beam of 3 mm diameter. X-rays emitted
from the feather were detected using a Si(Li) solidstate detector through an 8-pm-thick Be window (EG& G Co.). A graphite sheet with a 0.3-mm-diameter
pinhole (graphite pinhole absorber) or 74-pm-thick Al
was used as an absorber to attenuate the X-rays in the
low-energy region. The concentration of each traceelement was estimated from the sulfur concentration
determined by an ion gas chromatograph (Yokogawa
Co. IC100), the peak area, and the ratio of the theoretical X-ray yield calculated by the computer program
THICK in PIXAN.3)
Figure 1 illustrates the relationship between the concentration of the detected trace elements and the distance from the top of the feather. Measurements werecarried out at points along the shaft of the feather: 2,4, 6.5, 9, 11.5, and 15 cm from the top of the vane, andapproximately 1 cm away from the shaft. The concentration of lead decreased towards the bottom of thevane. At 2 cm from the top, the lead concentration
was 100 ppm, but at 15 cm from the top, it decreased
to 9 ppm. A similar trend was observed for zinc which
was also detected by the above method; however, therate of decrease of zinc concentration was lower thanthat for lead, as shown in Fig. 1. On the other hand,different elemental distributions on the vane were observed for manganese and iron. The concentrations of
School of Agriculture and Life Sciences, University of Tokyo

500

E
a.

•

.9:
co

0

~

50

C

!1.l

8

• Pb
&Zn

•

• Mn
•

F.

5
2

4

6

8

10

20

Distance from top of feather (cm)Fig. 1. Concentrations of lead, zinc, manganese, and ironin the feather of a jungle crow living in Tokyo detectedby PIXE analysis.
manganese were almost constant throughout the vane.
However, the concentrations of iron increased towards
the bottom of the vane.
A similar result was obtained from the measurements along the barb. The concentration of lead was
44 ppm at the top of the barb and 19 ppm near theshaft. It is known that feather replacement occurs regularly with change of season. In this replacement, a
new feather starts forming from the top of the vane andshaft in the first stage and then grows rapidly towards
the bottom of the vane. 4 ) Therefore, these results may
indicate that lead, as a toxic substance taken into thebody of jungle crows, is preferentially excreted intofeathers in comparison with other trace elements.
In summary, a PIXE analysis has been carried out
on different parts of the feather of a jungle crow livingin Tokyo. At 2 cm from the top of the vane, 100 ppm
of lead was detected. The amount of lead decreased towards the bottom of the vane. However, this tendency
was not observed for either manganese or iron detectedin the same vane. Therefore, lead appears to be preferentially excreated from the body to the feather duringfeather formation. We expect that the PIXE analysis
of different parts of feathers will be useful to understand and clarify the process of elimination of heavy
metals in birds.
References

1) L. L. Getz, L. B. Best, and M. Prather: Environ. Pollut.
12, 235 (1977).
2) H. Yoshiki, K. Maeda, A. Tonomura, T. Tsuruda, and
H. Higuchi: Proc. 4th Asian Symp. on AAWM, p. 288(1998).
3) E. Clayton: PIXAN: The Lucas Heights PIXE Analysis

Computer Package AAECjM113 (1986).
4) F. B. Gill: in Ornithology, (W. H. Freeman and Company, New York, 1990), p. 65.
185

RIKEN Accel. Prog. Rep. 33 (2000)

RBS Analysis of Na-Implanted Glassy Carbon
M. Iwaki and A. Nakao
Depth profiles of Na implanted in glassy carbon
have been obtained and analyzed using Rutherford
backscattering spectrometry (RBS).
Substrates used were glassy carbon (GC) sheets,
GC-20 made by Tokai Carbon with a size of 10 x
10 mm 2 and thickness of 1 mm. Before ion implantation, the surfaces were mechanically mirror-polishedby using a buffing wheel with diamond slurry. N aions were implanted at doses of 1 x 10 16 , 5 X 10 16 and1 x 10 17 ions/cm 2 and an energy of 150 keV at room
temperature. The beam current density was about
0.5 /-tA/cm2 to prevent surface heating by the beam itself. RBS measurements were carried out with 1.5 MeV
He ions and a fluence of 10 /-tC, using a Tandem-type
accelerator. A He-ion beam was irradiated in the direction normal to the specimen surface and the detector
angle was 168 degrees.
Figure 1 shows the RBS spectra for Na-implanted
GC at the doses of 1 x 10 16 , 5 X 10 16 , and1 x 10 17 ions/cm 2 . Arrows of C, 0 and Na indicate the positions of C, 0 and Na atoms at thesurface, respectively. The N a depth profiles are Gaussian at the doses of 1 x 10 16 and 5 x 10 16 ions/cm 2 .
The atomic ratio of Na/C is 0.03 at the maximum Naconcentration at the dose of 1 x 10 16 ions/cm 2 . At
the dose of 1 x 10 17 ions/cm 2 , the concentration of
N a atoms increased at the surface and it remained
constant in the implanted layers. The profile is considered to reflect high Na concentrations, generationof high compression and consequent migration of Na
atoms toward the surface. High concentrations of

186

3500

Na

3000
~ 2500c::l~ 2000~ 1500>= 1000
500
300

400

500

600

700

800

ENERGY (keV)

Fig. 1. RBS spectra of Na-implanted glassy carbon.
O-atoms can be seen at the surface. The appearanceof 0 atoms seems to be due to surface migration andoxygenation of Na atoms during and/or after ion implantation. The atomic ratios of Na/C and O/C atthe surface are 0.06 and 0.16 , respectively. Such phenomena have been observed in the case of Li and K
implantation in GC.
The depth at the peaks can be calculated from theenergy loss from the surface, assuming the atomiC density of implanted layers. However, it is difficult to determine the atomic density because the structure of
implanted layers changes from glassy to amorphous;consequently the depth profile of Na could not be obtained.

RIKEN Accel. Prog. Rep. 33 (2000)

Heavy-Ion Irradiation Effects in Bi-2223 Tapes
H. Ikeda, N. Kuroda, A. Iwase, T. Kambara, and R. Yoshizaki*
We have investigated the effect of columnar defects
on the irreversibility line for the point-pin-enrichedsample of Bi-2223 tapes. I) Since irradiation can introduce defects in a controlled manner, it can be used asa useful tool to probe the response of the a flux line
system to the known defect structure. Whether or notcolumnar defects act cooperatively with point defects
to pin vortices is not a trivial question.
Ag-Cu alloy sheathed tapes were prepared by the
powder-in-tube method. Ag-Cu alloy sheaths in thisstudy were filled with eu-poor Bi-2223 powder, sincecopper atoms were expected to diffuse into the inneroxide core from the outer Ag-Cu alloy sheath. We
introduced Hf elements into the Ag-Cu alloy sheathed
Bi-2223 tapes. This resulted in the improvement of thetransport J c' The details of the preparation method
and the fundamental properties of the samples havebeen reported elsewhere. 2)
Bi-2223 tapes with 3.0 x 3.0 x 0.1 mm 3 dimensions
were irradiated with 3.5 GeV 163Xe31+ ions irradiation at the RIKEN ring cyclotron facility to introduce columnar defects perpendicular to the tape surface direction. The total pin density was estimatedto be 7.2 x 10 10 cm- 2 , which corresponded to a doseequivalent matching field of B¢ = 1.4 ± 0.2 T . This
type of irradiation has produced continuous amorphous track with a diameter of ~ 6 nm throughout
the thickness of the Bi-2223 sample. We estimatedsample qualities using X-ray diffraction measuremens
and transmission electron microscopy. We confirmedthat the Hf atoms were substituted for 0.5-1% of
Sr by high-resolution analyztical electron mi-croscopy(HRAEM) .3) The magnetic properties were measured
using a superconducting quantum interference device(SQUID) magnetometer. The magnetic field was applied perpendicular to the wide surface of the tape.
Figure 1 shows the magnetic field versus the irreversibility temperature (Tirr ),using by solid symbols
for the irradiated Ag and Ag-Cu alloy sheathed Bi2223 tapes with columnar defects and open symbols
for the unirradiated tapes. We can observe that theirreversibility line curve for the irradiated Ag sheathedtapes is located on the higher temperature side of
the unirradiated tape samples below 4 T and merges
with the line curve for the unirradiated tape samples
at a magnetic field of about triplicate of B<f>. We
found that the irreversibility line curve for the Ag-Cu
alloy sheathed tapes was drastically shifted to higher
temperatures in the measured magnetic field up to 5 T

6Bi-2223

...-.

C

-

5

Xe-irradiation

4

irradiated- . - Ag-sheath---- Ag-Cu sheath

"C
Q)

I.L.

\\

.-+..I0Q)c:unirradiated" 6," Ag-sheath·n· Ag-Cu sheath

b

3

~\

2

bD

ca

:::E

~\.

···iit.... .251..." .."O~~~~~~~~--~~

o

20

40

60

80

100

120

Temperature (K)Fig. 1. The irreversibility temperatures are plotted in the
H-T plane using by solid symbols for the irradiated Ag
and Ag-Cu alloy sheathed Bi-2223 tapes with columnar
defects and open symbols for the unirradiated tapes.

following Xe-ion irradiation. This behavior suggeststhat the pinning force of the irradiated Ag-Cu alloy
sheathed tapes is larger than that of the Ag sheathedones.
In fact , according to the results of the pinning force
measurement , the field dependence of F p of the Bi2223 tape samples was improved by the Hf substitution
for Sr due to the collective pinning. 3) Therefore, it isexpected that the columnar defects will function as
effective pinning centers in cooperation with the point
defects induced by Hf doping.
We observed the effect of the columnar defects in the
Bi-2223 tapes. We found that the irreversibility curveof the irradiated Ag-Cu alloy sheathed tape sample islocated on the higher temperature side of the irradiated Ag sheathed tape sample even in magnetic field
higher than the triplicate of the matching field B<f>.
References
1) L. Civale et al.: Phys. Rev. Lett. 71, 4124 (1993).
2) M. Ishizuka et al.: Physica C 252, 239 (1995).
3) H. Ikeda et al.: in Advances in Superconductivity IX,
edited by S. Nakajima and M. Murakami, (SpringerVerlag, Tokyo, 1997), p. 847.

Institute of Materials Science, University of Tsukuba

187

RIKEN Accel. Prog. Rep. 33 (2000)

A New Method for Determining the Vacancy Formation Energy ofMetals Using the Positron Age-Momentum Correlation Technique t
N. Suzuki, Y. Nagai,* and T. Hyodo
The positron lifetime spectra for materials containing mono-vacancies consist of two components. The
shorter lifetime is the inverse of the sum of the positron
annhilation rate in the bulk and the trapping rate into
vacancies. Thus it is possible, in principle, to determine the vacancy formation energy from the temperature dependence of the shorter lifetime.
The analysis used to obtain the vacancy formationenergy is, however , usually performed using the averaged lifetime, since it is difficult to obtain a reliablevalue for the short lifetime, which is usually shorter
than the instrumental time resolution. 1)
In this report we present a new method for separating the short-lifetime component using the positron
age-momentum correlation (AMOC) technique. 2 )This method characterizes the AMOC spectrum
N (p , t) (number of counts vs, the momentum of theannihilating electron-positron pairs and the positron
lifetime) in terms of the time-dependent line-shape parameter 5(t).2) When the positrons annihilate fromtwo different states which have different S parameters,
5(t) is written as,5( ) = 51 ·ll(t) + 52 ·l2(t)

t

,

(1)

N(p: t)dp,

(2)

L(t)

L(t) = h(t) + l2(t) =J

where li(t) and 5 i denote the lifetime spectrum andthe time-independent specific 5 value for the i-th state,
respectively. It then follows thath(t) =

81t ) -552 . L(t) ex (5(t) - 52) . L(t).
1 -

(3)

2

If the lifetime of the second component is apprecia-

bly longer than that of the first, 8 2 is determined byaveraging 5(t) in the time range where the second component is dominant. It is then possible to isolate theshorter lifetime component II (t), apart from the normalization factor, solely from the AMOC data.
The reconstructed short-lifetime spectrum of Zn at
453 K is shown in Fig. 1. The lifetime 11 of this spectrum can be obtained by simply fitting these data toa single-component exponential decay function convoluted with the resolution function. The solid curve
represents the result of the fit and reproduces the spectrum very well.
The values of 11 thus obtained are plotted against
temperature in Fig. 2. The line represents the result oft

188

Condensed from the article in Phys. Rev. B 60, R9893(1999)
Institute for Material Reserch, Tohoku University

100 ~--~----~--~L-~U=~RR~

0 1 2

time (ns)Fig. 1. Reconstructed positron lifetime spectrum for the
shorter lifetime component for Zn at 453 K.

Fig. 2. The shorter lifetime values plotted against the temperature.
fitting using the two-state trapping model. l ) The fit issatisfactory. The vacancy formation energy ED for Zn
determined from the fitted curve is 0.50 ± 0.06 (eV).
This value is in good agreement with the reported
value.
Note that ED was determined using only the data forthe temperature range 383-513 K, considerably lower
than the melting point of Zn (693 K). In the conventional determination of ED by positron techniques, itis necessary to perform measurements at temperatures
close to the melting point to estimate the parameters
for fully trapped positrons.
Utilizing this advantage, we are now planning to determine the vacancy formation energy of alloys that
undergo a structural phase transition, which prevent a
consistent analysis of the data, at high temperatures.
References
1) See for example, R. N. West: in Positron in Solids,
edited by P. Hautojiirvi, (Springer, Berlin, 1979), p. 89.
2) N. Suzuki, Y. Nagai, and T. Hyodo: Radiat. Phys.
Chern. (to be published).

7. Miscellaneous

RIKEN Accel. Prog. Rep . 33 (2000)

Neutrino Advanced Generation with Accelerated Muon
K. Nagamine
A neutrino (ve, De, VJ-L' DJ-L' Vn Dr), a massless elementary particle, if generated in the form of an intense andhigh-quality energetic beam, can be useful not only forparticle-physics experiments such as neutrino oscillation studies, but also for probing the inside of gigantic
objects such as the earth itself. Some proposals l ) suggest using neutrinos to explore the nature of the earth.
An intense neutrino beam is proposed to be generatedusing an intense and high-energy (multi-TeV) proton
accelerator. However, because of the limited qualityof the neutrino beam, the idea should be consideredunrealistic, or at least very difficult to be realized.
Using high-energy proton accelerators which produce energetic pions (7r+, 7r-), one can expect two
methods for neutrino generation: (1) A pion decay to aneutrino through 7r+ ---+ J..L+ + vJ-L or 7r- ---+ J..L- + DJ-L' (2)A muon decay to neutrinos through J..L+ ---+ e+ + Ve + DJ-L
or J..L- ---+ e- +De+vJ.L' Thus far, most of the acceleratorbased neutrino experiments, including the inner-earth
studies described above, are considered using an energetic neutrino beam obtained through the decayof energetic pions or muons based upon the decaykinematics law. The quality of the neutrino beam canbe considerablely improved once the beam quality ofthe parent particle, pions or muons, can be improved.
Recently, the concept of ultra slow J..L+ was
proposed 2 ) and realized at KEK-MSL.3,4) In addition,
the possibility of the use of this ultra slow J..L+ as the ion
source for further acceleration towards J..L +J..L- colliders
has been emphasized. There are two processes in therealization of an ultra slow J..L+ source: (1) Thermal Mu(J..L+e-) production in vacuum by stopping J..L+ at therear side of the selected metallic material, such as hottungsten, followed by J..L+ diffusion towards the surface
as well as Mu evaporation from the surface of the foil,(2) Efficient muonium ionization using a method suchas laser-resonant ionization via 1s---+ 2p ---+ unbound excitation utilizing intense pulsed lasers in combination
with a pulsed muon beam.
Recently it has been noted that, in combination
with the large-solid-angle MeV muon source, anintense ultra-slow J..L+ source with an intensity of
10 12 J..L+ /s and an emittance of better than 10- 7 rad·m
can be generated in the setup shown in Fig. 1. In thissetup a thick carbon target with a large-solid-angle
pion collector will be installed at the external beamline of medium-energy, such as 1 GeV, protons
followed by the pion decay section (super-super muonchannel) coupled with the ultra slow J..L+ generator
mentioned above. Preliminary optics design workfor the gO-degree muon extraction from the proton
beam has been done in strong collaboration with
K. Ishida. By adopting a strong superconducting
solenoid for pion collection and a reasonable lengthof a decay solenoid installed at the strongest existing
pulsed proton beam line of the ISIS synchrotron
at RAL (UK), one can obtain a source with anintensity of greater than 10 10 J..L+ Is. The momentum spread of the J..L+ obtained at the end of the
decay solenoid is very large (nearly ± 40%). However,
MirrorHotW

SlowJ!

+

Decay Solenoid
Pion

Production Target
Fig. L Intense ultra slow J.L+ production employing high-intensity muon production via a large acceptancepion collection.

189

Pion capture &Decay Solenoid//

lOkeV It+ generator

Race Track
Storage Ring

Fig. 2. Proposed scheme of the advanced generation of a neutrino beam based upon adecay of the muon accelerated from the ultra-slow J.L + ion-source.
it becomes possible to stop generated J-l+ inside a multilayer of hot W , so that an intense ultra slow J-l+ beam
can be generated by the method of laser-resonant ionization of thermal muonium emitted from the surfaceof hot W. Simulation calculations are in progress toconfirm the characteristic features of the ultra slow J-l+
produced after optimization.
The high-intensity ultra slow p,+ produced can beapplied as an ion source for acceleration, by installing radio frequency quadropole (RFQ) and drifttube linac (DTL) preaccelerators followed by, e.g., asuper-conducting linac. One of the most important
applications of the intense low-energy p,+ source is as
an advanced source of neutrinos (iiJ.t, ve ) with accelerated p,+. By installing a relevant decay section for
the accelerated p,+, intense and high-quality neutrinos
would be produced via p,+ ~ iiJ.t + Ve + e+ , employing
the setup shown in Fig. 2.
The key factors in the realization of this advanced
neutrino beam can be summarized as follows.
(1) Quality of the accelerated muons
One can expect a greater than 10 10 p,+ source withan extremely small phase space (0.2 eV x (cm)2).
(2) Muon decay section
A race-track-type muon storage ring, as shown in

190

Fig. 2, is an attractive idea.
(3) Quality of the produced neutrino beam
Regarding the decay cone, the opening half-angle,
BJ.t , becomes smaller at higher muon energy (EJ.t), withthe relationship of mJ.tIEw
Using the future intense pulsed proton source (withmore than MW-order power) to be available also fora spallation neutron source, an intensity of 10 12 p,+ Is
can be obtained. A rough estimate for other proton
accelerators can be obtained by scaling to the proton
beam power.
Helpful discussions with Drs. · K. Ishida and Y.
Miyake are acknowledged.
References

1) A. De Rujula, S. L. Glashow, R. R. Wilson, and G.
Charpak: Phys. Rep. 6 , 341 (1983) .
2) K. Nagamine and A. P. Mills, Jr.: Los Alamos Report
LA10714-C, 21 (1986); K. Nagamine: At. Phys. 10,
225 (1987).
3) K. Nagamine, Y. Miyake, K. Shimomura, P. Birrer, J . P.

Marangos, M. Iwasaki, P. Strasser, and T. Kuga: Phys.
Rev. Lett. 74, 4811 (1995).
4) Y. Miyake, J. P. Marangos, K. Shimomura, P. Birrer,
T. Kuga, and K. Nagamine: Nucl. Instrum. Methods
Phys. Res. B 95, 265 (1995).

RIKEN Accel. Prog. Rep. 33 (2000)

Light Hadron Spectrum in Quenched Lattice QeD
S. Kim* and S. Ohta
Reproducing the known light hadron mass spectrum
is the most important test that the numerical lattice quantum chromo dynamics (QCD) has yet to pass,in spite of the steady progress I ) since the pioneering
works of Weingarten and Hamber and Parisi. 2) The
main obstacle is the difficulty in including light dynamical quarks, and consequently, the available full-QCD
calculations still suffer from a too heavy quark mass,
too coarse lattice spacing or too small lattice volume.
However, with the quenched approximation in which
one neglects dynamical quark loops, recent calculations have used sufficiently fine lattice spacing and sufficiently large lattice volume to allow understanding of
the systematic errors arising from them. Indeed, recent
quenched-approximation calculations have collectively
revealed that both of these errors are smaller than thestatistical noise, albeit with rather heavy quarks. Nevertheless these calculations leave three major problems
unresolved: The nucleon to p-meson mass ratio is too
high, the pion to p-meson mass ratio is too high, andextrapolation to realistically light quark mass values
is necessary. Hence quenched-approximation calculations with realistically light quark mass values on a
sufficiently large and sufficiently fine lattice such as
the one we report here 3) are desired.
We chose a gauge coupling of 619 2 = 6.5 and alattice volume of 48 3 x 64. These pa~a~rp.eters correspond to the lattice spacing of a = 0.0544(9) fm orthe cutoff of a-I = 3.63(6) GeV and a spatial volume of (2.59(5) fm)3. We use a staggered quark because it is superior to the Wilson one for controlling
the quark mass; the quark mass is well defined andprotected by the remnant U (1) chiral symmetry in
the former, while in the latter, one encounters the intractable problem of defining the critical hopping parameter under the inevitable presence of exceptional
gauge configurations. 4) For the gauge part, we use asingle-plaquette Wilson action. This is because ourlattice spacing is sufficiently fine and we do not require any help from action improvement to approachthe continuum limit.
The main result is summarized in our Edinburgh
plot (Fig. 1) where two mass ratios, mN Imp andm 1i /m p , are plotted against each other. For our lightest bare quark mass of mqa = 0.00125 (approximately
4.5 MeV), we obtain mN Imp = 1.230 ± 0.035 andm1i/mp = 0.273 ± ·0.006. The former is in good agreement with the observed value, although the latter remains approximately 50% larger. The proximity ofthese results to the continuum limit is measured by
the extent of breaking of the flavor symmetry in pion

1.6

~o
Q"

E

"E
z

1.0

0.00

0.25

0.50

0.75

1.00

Fig. 1. The nucleon to p mass ratio vs pion to p mass
ratio at 61 l = 6.5 for mqa = 0.05, 0.04, 0.03, 0.02,
0.015, 0.01, 0.0075, 0.005, 0.0025, and 0.00125. The
lower circle represents the experimental value and theupper circle represents the nonrelativistic limit.

and p meson channels (m7l'2a-m1ia) and (m p2 a-m pa).
These breakings are expected to decrease as O(a 2 ), as
the lattice spacing a approaches the continuum limit
value of O. We can see that they are hidden below statistical errors for sufficiently light quark mass values:
The symmetry is restored adequately. In other words,
the lattice is sufficiently close to the continuum limit.
In conclusion, we achieved a realistic nucleon to pmeson mass ratio of mN Imp = 1.23 ± 0.04 (statistical) ± 0.02 (systematic) in our quenched lattice QeD
numerical calculation with staggered quarks, without
relying on any extrapolation. The systematic error ismostly due to the finite-volume effect, and the finitespacing effect is negligible. The breaking of the flavor
symmetry in the pion and p meson is no longer evident.
References
1) See recent "Lattice" Conference Proceedings for theCurrent Status, e.g., Nucl. Phys. B (Proc. Suppl. ) 63
(1998).
2) D. Weingarten: Phys. Lett. B 109, 57 (1982); H. Hamber and G. Parisi: Phys. Rev. Lett. 47, 1792 (1981).
3) S. Kim and S. Ohta: Phys. Rev. D, in press. (heplat/9912001) and references therein.
4) W. Bardeen et al.: Phys. Rev. D 57, 1633 (1998); Nucl.
Phys. B (Proc. Suppl.) 63, 141 (1998).

Sejong University, Korea

191

RIKEN Accel. Prog. Rep. 33 (2000)

Monte Carlo Simulation of Supersymmetric Matrix Model
J. Nishimura and T. Hotta
Large N reduced models are the zero-volume limit
of gauge theories . They have been developed for the
study of gauge theories at the large N limit. I) Recently
there has been a revival of interest in these models in
the context of nonperturbative formulations of string
theory.2,3) An important feature in this context is thepresence of supersymmetry. The bosonic counterpartof the model is well understood,4) but the inclusion offermions makes the system far more complicated. In
our project, we study such a supersymmetric model
numerically. The partition function of the model that
we investigate is given byz=JdA e- Sb

J

d1jJd1jJ* e- S ',1

2

Sb = - - 2 tr[AJl, Avl ,4g
Sf = -:2 1jJ~(rJl)oO[AJl' 1Pol) ,
tr(

(1)

where AJl (J.-L = 1,···4) are N x N traceless Hermitian matrices and 1jJo (0 = 1,2) are traceless N x N
complex matrices. This model is manifestly invariant
under Lorentz transformation, where AJl transforms asa vector and 1/Jo transforms as a Weyl spinor. r Jl are
2 x 2 matrices acting on the spinor components:rl = iO'l, r2 = i0'2, r3 = i0'3, r4 = r:--(2)

The model can be regarded as the four-dimensionalcounterpart of the IIB matrix model. 3)
The integration over fermionic variables can be done
explicitly and the result is given by det M, M beinga 2(N 2 - 1) X 2(N 2 - 1) complex matrix. Hence thesystem we want to simulate can be written in terms ofbosonic variables asz = ~4

J

dA e-

Sb

detM.

(3)

The determinant det M is known to be real positive.
We therefore introduce a 2(N 2 - 1) X 2(N 2 - 1) Hermitian positive matrix D = Mt M, so that det M =Vdet D, and the effective action of the system takes
the form
1

Seff = Sb - '2lndetD.

(4)

We apply the hybrid R algorithm 5) to simulate thissystem. We use the exact result,192

to check the code and the numerical accuracy.
We first study the space-time structure of the reduced model. In the IIB matrix model, the eigenvalues of the bosonic matrices AJl are interpreted
as space-time coordinates. 3,6) We measure the extent
of the eigenvalue distribution and find that it scales
as y0NI/4, which is consistent with the branchedpolymer picture based on one-loop ·expansion. 6)
We then study the large N scaling of correlation
functions of Wilson loop operators, which correspondto string creation operators in the IIB matrix model. 7)
This issue has been addressed in the two-dimensional
Eguchi-Kawai model, where nontrivial large N scaling has been observed. B) We measured the correlation
functions up to three-point functions , and found thatthey scale universally in the large N limit.
Finally, we also study whether the large N reduced
model is equivalent to the ordinary gauge theory aspresented by Eguchi-Kawai.l) For this purpose, it isconvenient to consider a model without a traceless condition on Aw Such a model has the U(1)4 symmetry
AJl ~ AJl + 0J.L' which is spontaneously broken. Hencethe equivalence to ordinary gauge theory is nontrivial,
since this equivalence is' guaranteed only if the symmetry is not broken. However, the breaking is much
milder than in the bosonic case; the attractive potential among the eigenvalues of the AJl's, which induces
the spontaneous symmetry breaking, is suppressed by'liN due to supersymmetry.6) We found that in the
supersymmetric case, the equivalence does hold in theintermediate scale but not throughout the entire scale,
while in the bosonic case, the equivalence does not holdin any range of the scale.
References
1) T. Eguchi and H. Kawai: Phys. Rev. Lett. 48, 1063
(1982) .
2) T. Banks, W. Fischler, S. H. Shenker, and L. Susskind:
Phys. Rev. D 55, 5112 (1997).
3) N. Ishibashi, H. Kawai, Y. Kitazawa, and A. Tsuchiya:
Nucl. Phys. B498, 467 (1997).
4) T. Hotta, J. Nishimura, and A. Tsuehiya: Nuel. Phys.
B 545, 543 (1999).
5) S. Gottlieb, W. Liu, D. Toussaint, R. L. Renken, and
R. L. Sugar: Phys. Rev. D 35, 2531 (1987).
6) H. Aoki, S. Iso, H. Kawai, Y. Kitazawa, and T. Tada:
Prog. Theor. Phys. 99, 713 (1998):
7) M. Fukuma, H. Kawai, Y. Kitazawa, and A. Tsuehiya:
Nucl. Phys. B 510, 158 (1998).
8) T. Nakajima and J. Nishimura: Nuel. Phys, B 528 , 355(1998) .

RIKEN Accel. Prog. Rep. 33 (2000)

New Method for Trace Element Analysis Using the Electron
Cyclotron Resonance Ion Source and Heavy-Ion Linac
M. Kidera, T. Nakagawa, K. Takahashi, S. Enomoto,T. Minami,* M. Fujimaki,
E. Ikezawa, O. Kamigaito, M. Kase, A. Goto, and Y. Yano
We measured the contamination in an Al 2 0 3 rod
and in composite elements of cinnabar (collected fromthe Tenjinyama ancient tomb) using the electron cyclotron resonance ion source (ECRIS) and the RIKEN
linear accelerator (RILAC) complex. Elements of mass
number smaller than 100, such as 50y, 55Mn and 75 As,
were mainly identified by the system.
Since the 1960s, the technique of accelerator mass
spectrometry (AMS) has been developed in cooperation with an electrostatic-tandem accelerator. A negative ion source is conventionally used for a tandem
accelerator , and the development of an ion source isan important research theme. The negative ionizationof the element strongly depends on its electron affinity. For the production of negative ions from elementswith low electron affinity, great effort is required forsample preparation. In particular, it is impossible toproduce negative ions from rare gases, such as Ar andKr . In many cases, the measurement has a large margin of error due to the effect of the various treatmentsof the element. These are some of the disadvantagesof using a tandem accelerator for AMS. In addition,
when using a tandem accelerator to identify impurities
in materials, automation for scanning both the analyzing magnet of the injection and extraction side of
the accelerator is required, which is quite complicated,leading to uncertainties in the determined amount of
impurities. To overcome this, we combined the ECRIS
and heavy-ion Linac to conduct experiments of element
analysis . The 18 GHz ECRIS 1) at RIKEN was used as
the external ion source of the RIKEN linear accelerator (RILAC). 2) The production of positive ions does
not depend on ionization tendency in the ECR plasmaand highly charged positive ions were produced in the
ECR plasma for all elements at a high temperature.
The acceleration and transportation depends only on
the mass-to-charge ratio (Ajq). Ions with the same
Aj q were simultaneously analyzed and detected by thissystem. With Ajq = 3, 4, and 5, approximately 90%
of all elements can be accelerated and analyzed.
The composite elements of cinnabar from the Tenjinyama ancient tomb were measured using the same
system. Approximately 100 mg of cinnabar was placed
into a 4-mm-diameter, 2-mm-thick Ta tube. The tipof the Ta tube was closed using pliers, and two 1mm-diameter holes were formed in the upper side of
the Ta tube. The powdered sample was heated by
ECR plasma. The particles with Alq = 5, anaCollege of Toyooka(20Ne)

35

C1 ( 40Ar)

Sn,Cd
C30 Xe)

I. 1
o

1000
~E(Channelnumbe~

Fig. 1. D..E spectrum for measurement of cinnabar.
lyzed using the first analyzing magnet, were accelerated to 1.0 MeY lu using RILAC and the variablefrequency RFQ (radio-frequency quadrupole linac)
pre-accelerator. 3)
The ~E spectrum is shown in Fig. 1. By fixing theacceleration parameter to Ajq = 5, the mass number ofdetected elements is a multiple of 5. The accelerator
has large ambiguity in terms of mass resolution due
to influences such as the fluctuation of the RF phase;
however, in the system used in this investigation, thedetected elements were almost certain to have AI q =5, because elements were reselected by the analyzing
magnets.
We established a method for the measurement of therelative abundance of elements in a sample by using
ECRIS. Unlike conventional AMS, this system allows
the measurement of numerous elements at the sametime. The effect of spectroscopic interference is negligible owing to ionization in the high-temperature fieldby the ECR plasma, implying that the number of elements was increased and the margin of measurement
error was decreased.
References

1) T. Nakagawa et al.: Nucl. lnstrum. Methods Phys. Res.
A 396, 9 (1997).
.
2) M. Odera et al.: Nucl. Instrum. Methods 227, 187(1984) .
3) O. Kamigaito et al.: Rev. Sci. lnstrum. 70,4523 (1999) .

193

194

IV.

NUCLEAR DATARIKEN Accel. Prog. Rep. 33 (2000)

Status Report of the Nuclear Data Group
Y. Tendow, A. Yoshida, and K. Kitao
Until now, the RIKEN Nuclear Data Group has continued three kinds of long-term nuclear data activity
described below.
(1) Nuclear reaction cross section data (EXFOR)
Since 1983, our group has been a member of theworldwide network for the compilation of the charged
particle nuclear reaction cross sections coordinated by
the IAEA Nuclear Data Section (NDS). The tasks ofthis network are to collect charged particle reaction
cross sections and compile them into a special format
called EXFOR (EXchange FORmat). The compiled
data are incorporated into the master database andprovided to clients free of cost upon request.
First we limited data collection to the cross section data of important reactions producing the following twenty typical radioisotopes for medical applications: 11C, 13N, 15 0, 18F, 28Mg, 52Fe, 67Ga,
68Ge, 74 As, 77Br, 82Br, 77Kr, 81 Rb, 82m Rb, 111 In,
123Xe, 127 Xe, 123 1, 124 1, and 1251. Subsequently, inorder to maintain the completeness of the database,we extended the scope of data collection to the important reaction data not included in the EXFOR
master file.
So far, we have added 53 entries, 'R0001' through'R0053' containing as many as 535 excitation functions
in total to the EXFOR database.
(2) Evaluated Nuclear Structure Data File (ENSDF)
We have been participating in the ENSDF compilation network coordinated by the Brookhaven National
Nuclear Data Center (NNDC). The task of the network is to evaluate various existing experimental nuclear structure data to construct and recommend a reliable nuclear data set and level scheme for each nuclide
in a mass chain.
We have thus far evaluated nuclear structure data
for mass chains A = 120, 121 , 127 and 129, andthe results have been published in the Nuclear Data
Sheets.1- 5)
A draft of a new evaluation of the A = 120 masschain is now under the author's review prior to theprinting. Because much new data on high-spin states
for A = 129, as well as for other neighboring masses,
have been accumulating since our last evaluation,

we are planning to make partial update of A = 129
mass chain in the near future.
(3) Nuclear Science References (NSR)
We are engaged in collecting and compiling the secondary references printed in Japan (unpublished works
such as annual reports, conference proceedings, etc~)
into the Nuclear Science References (NSR) file format
and transmitting them to the NNDC. The NSR data
are disseminated through on-line network services andalso in print as 'Recent References'.
The compilation of the 1998 annual report containing 150 papers has already been completed and transmitted to the NNDC. The Japanese secondary sources
surveyed were as follows (shown in the NSR file codename):RIKEN (RIKEN Accel. Prog. Rep.),
JAERI-TV (JAERI Tandem & V. D. G. Rep.),
JAERI-TIARA (JAERI Takasaki Ion Acc. Advanced Rad. Appl.),UTTAC (Univ. Tsukuba Tandem Accel. Center),
RCNP (Res. Center Nucl. Phys., Osaka Univ.),
OULNS (Osaka Univ. Lab. Nucl. Studies),
CYRIC (Cyclo. Radioisot. Center, Tohoku Univ.),
KUTL (Kyushu Univ. Tandem Accel. Lab.).
The compilation of works for the 1999 annual report
is now in progress.
The RIKEN Nuclear Data Group could not sparethe manpower in recent years to carry out other workthan the three database activities mentioned above.
With the upcoming reorganization of the Radiation
Laboratory, we will have to reconsider our activities asa whole.
References
1) A. Hashizume, Y. Tendow, and M. Ohshima: Nucl.
Data Sheets 52, 641 (1987).
2) T. Tamura, Z. Matumoto, A. Hashizume, Y. Tendow,
K. Miyano, S. Ohya, K . Kitao, and ' M. Kanbe: Nuel.
Data Sheets 26, 385 (1979).
3) A. Hashizume, Y. Tendow, K. Kitao, M. Kanbe, and T.
Tamura: Nuel. Data Sheets 35, 181 (1982).
4) K. Kitao and M. Ohshima: Nuel. Data Sheets 11, 1(1996).
5) Y. Tendow: Nuel. Data Sheets 11, 631 (1996).

195

196

V.

DEVELOPMENT OF ACCELERATOR FACILITIESRIKEN Accel. Prog. Rep. 33 (2000)

Biased Electrode Method for RIKEN 18 GHz ECRIS
Y. Higurashi, T. Nakagawa, M. Kidera, Y. Miyazawa, M. Hemmi , T. Chiba,
M. Kase, T. Kageyama, A. Goto, and Y. Yano
In order to increase the beam intensity of highly
charged heavy ions from ECRIS , several methods havebeen suggested and successfully applied in many laboratories in the last decade. The installation of anelectrode into the plasma chamber is one of the mostpopular methods. In RIKEN, we have also applied thismethod and successfully increased the beam intensityof highly charged heavy ions. In spite of the great success of this method, the mechanism is still not completely clear. As a first step toward understanding themechanism of this method, we measured the beam intensity while changing the electrode position and thebiased voltage.
The design and performance of the RIKEN 18 G HzECRIS without using the biased electrode is describedin Ref. 1. Figure 1 shows the cross-sectional view of
the RIKEN 18 GHz ECRIS with a stainless steel electrode. The diameter and thickness of the electrode are
18 and 1 mm, respectively. A negative bias voltage isapplied between the electrode and plasma chamber asshown in Fig. 1. The electrode can also be used at thefloating potential by disconnecting it from the electric
power supply. The electrode is placed on the axes ofthe plasma chamber. The position of electrode (L) is

defined in Fig. 1. The axial position of the electrode isremotely controlled with an accuracy of 0.1 mm.
For all elements heavier than carbon, gas mixing
is usually used to obtain a higher intensity of highly
charged heavy ions. In the present case, we usedoxygen as a mixing gas to produce Xe ions. The plasma
1000
84Kr
136Xe

~

(85% enriched)..!..100

24+

:i.

~

'0
c:
(I,)

-

.=

E
C'CS

(I,)

m
32+

20

Charge State
Fig. 2. Beam intensity of highly charged ions from gaseous
elements. Open and closed circles are results without
using and using the disc, respectively.

;0

2

j

o Electrode position (L)(em)

Fig. 1. Cross-sectional view of RIKEN 18 GHz ECRIS.

3

4

5

6

7

8

Eleetode Position (L) ( em)Fig. 3. Beam intensity of Xe 20 + as a function of the electrode position at the RF power of 200 w.
197

60

L=4.2cm

60

L=4.46cm

60

L=5.5 cm

<'::t
II)

~40

40

40

"ij

c

II)

c
E
20
as

20

II)

m

o 100 200 300 400 500

0 100 200 300 400 500

60

0 100 200 300 400 500
Negative Bias Volatge (V)L=7.0cm

40

20

I

I

I

I

o 100 200 300 400 500

Negative Bias Volatge (V)0 100 200 300 400 500
Negative Bias Volatge (V)Fig. 4. Beam intensity of Xe 20 + as a function of the negative bias voltage for several
electrode positions.

chamber wall is covered with aluminum tubing (of1 mm thickness). The aluminum oxide surface emits
several secondary electrons per primary electron impact, which helps increase the plasma density. I)
Figure 2 shows the summary of the beam intensities
inclesise of the highest beam intensity of the gaseous
elements. The closed and open circles are the results
obtained using and without using the electrode, respectively. The beam intensity of highly charged ions
was strongly enhanced with the use of the electrode,e.g. , the intensity of 300 ettA of Ar l l + is almost two
times higher than that resulting whithout using theelectrode. 2 ,3 )The measurement was performed under the condition that the ion source was tuned for producing
a Xe 20 + beam at the bias voltage of 0 V. The gaspressure of the plasma chamber was 7 x 10- 7 Torr.
The maximum and minimum magnetic field strengthof the mirror magnetic field were 1.4 and 0.47 T ,respectively. The extraction voltage was 10 kV. The
injected microwave power was 200 W. For the experiment, we did not change these parameters except for
the negative bias voltage and position of electrode.
Figure 3 shows the beam intensity of Xe 20 + as afunction of electrode position at a bias voltage of 0 V.
The beam intensity strongly depends on the positionof the electrode. It oscillated as the electrode position

198

changed from L = 2 to 6 cm. We infer this oscillation
may be caused by the standing waves of the micro-wave(18 GHz rv 17 mm) ,4) however its mechanism is still
not clear. Additionally, when the electrode position(L) is near the ECR plasma (L = 6- 7 cm), the beam
intensity decreased as a function of L.
Figure 4 shows the beam intensity dependence Landthe negative bias voltage. At smaller values of L, thebeam intensity decreases with increasing negative bias
voltage. However, the beam intensity increases withnegative bias voltage when the electrode is placed far
from the chamber wall.
References
1) 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. 4077
(1996).
2) T. Nakagawa, S. Biri, M. Kidera, 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).
3) 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).
4) M. Delaunay, B . Jacquot et, and M. Pontonnier: Nucl.
Instrum. Methods Phys. Res. A 305, 223 (1991).

RIKEN Accel. Prog. Rep. 33 (2000)

Present Status of 14.5 GHz Caprice in RIKEN
Y. Kanai, Y. Nakai, H. Ohyama, T. Kambara, and Y. Yamazaki
The ECRIS (14.5 GHz Caprice) and the experimental beam lines were built in 1994- 1995 in the accelerator research annex for atomic physics experiments. 1)
This year, we moved the ECRIS and all setups to the
Nishina building. The ECRIS and the beam transportline (analyzing magnet and triplet quadrupole magnets) were transferred to the ion source room for the
AVF cyclotron. The experimental beam line (switching magnet and four beam lines) and experimental setups were transferred to the new experimental hall for
low-energy highly charged ions. The beam transportline passes through the wall between the ion source
room and the experimental hall. The power supplies
for the ECRIS and the beam transport line were situated in the ion source room. The ECRIS and the beamtransport system are controlled from the control deskin the experimental hall.
On this movement, we have not changed the configuration of the beam focussing elements. 1) Due tothe 56 cm difference in the floor level between the ion
source room and the experimental hall, the height ofthe beam lines was about 94 cm and 150 cm in the ion
source room and in the experimental hall , respectively.
The double-wall plasma chamber made of stainlesssteel (SUS) with an aluminum sheet was replacedwith a single-wall aluminum (AI) chamber, which is
expected to provide higher charge state ions. 2 ) In the
middle of October , we conducted a test of the ECRIS
and beam transport system. Typical ion currents
before and after the replacement are summarizedin Table 1. The extraction voltage was 15 kV andthe size of the beam was collimated by the slits to
18 mm x 18 mm before the Faraday cup. The data
indicate that the Al single-wall chamber provides
higher currents, particularly at higher charges, as
expected. We note that by using the Al sheet, theion currents at a higher charge state were increased
as compared to those with the simple SUS chamber, as

Table 1. Typical ion currents from 14.5 GHz Caprice in
RIKEN. Extraction voltage is 15 kV. Beam is collimated by slits to 18 mm x 18 mm. a: single-wall plasmachamber made of aluminum, b: double-wall plasmachamber made of stainless steel with aluminum sheet.

Ions currents (eJ-LA)
0 3+
0 5+
0 6+
0 7+
Ar 8 +
Arl1+
Ar 14 +
Ar 16 +

740 a
232 a
330 a
60 a
175 a
64 a
5a
0.3a

464 6

370 b
350 b
37 b
291 b
68 b
3.5 b
0.12b

reported before. 3 ) On the basis of the present results,
we can put forth that the Al single-wall plasma chamber is more effective than the SUS double wall plasmachamber with the Al sheet to obtain the higher charge
state ions. This is due to the difference in the area of
the Al surface in the plasma chamber between the Al
chamber and the SUS chamber with the Al sheet. 2)
We will test the deceleration mode of the beamtransport to use the very slow highly charged ionsat the experimental setups.4) Following this test, we
will start the experiments using ion beams from the
ECRIS.
References
1) Y. Kanai et al.: RIKEN Accel. Prog. Rep. 29, 208(1996) .
2) D. Hitz et al.: Rev. Sci. Instrum. 67, 883 (1996).
3) Y. Kanai et al.: RIKEN Accel. Prog. Rep. 30, 168(1997).
4) M. Kitajima et al.: RIKEN Accel. Prog. Rep. 31, 157(1998) .

199

RIKEN Accel. Prog. Rep. 33 (2000)

Development of Compact High Current Multicharged Ion Source
for RIKEN RI Beam Factory
S. Bhattacharjee, T. Nakagawa, M. Kase, A. Goto, and Y. Yano
Ion sources form an integral part of an accelerator facility. 1,2) High-current multicharged ion beams
are one of the major requirements of the RIKEN RI
beam factory. Electron cyclotron resonance ion sources(ECRIS) have been successfully applied for several
years. However, specific needs such as high-current
maximally charged heavy ions and the increasing demand for higher beam intensities 3 ) have initiated aquest for new types of ion sources. To address theforthcoming challenges, the development of ion sources
using novel concepts is essential.
The performance of an ion source is greatly determined by the characteristics of the source plasma. 3- 5 )In order to obtain higher beam intensities and multicharged states, it is imperative to increase the electron density, the electron temperature and the ion andelectron confinement times. With such an objective,
we attempt to improve upon these plasma parameters
using methods that have not been previously explored.
In ECRIS, the bore of the plasma chamber is usually made larger than the cutoff dimension of the fundamental waveguide mode to permit wave propagationand plasma sustenance. The waves are launched withthe propagation vector parallel to the axial magnetic
field, created by electromagnetic coils. The axial mirror field, although useful for plasma confinement andheating, has a loss cone and instability, such as drift
instability. Moreover, the plasma uniformity can become poor and heating can be inefficient when there
are large gradients of the magnetic field. 6 )Studies 7 ) have shown that, for waves launched perpendicular to the magnetic field, a peripheral arrangement of permanent magnets in a multicusp geometryaround the waveguide (plasma chamber) helps to obviate the geometrical cutoff problem. In this way thelaunched microwaves can be efficiently guided into theplasma chamber with a cross section even smaller thanthe cutoff value. The reduced bore diameter increases
the microwave power density which aids in the production of a plasma much denser than the cutoff density.
Moreover, perpendicular wave launching favors resonance heating such as upper hybrid resonance, which is
unexpected for waves launched parallel to the magnetic
field. The absence of electromagnetic coils results in
a compact device. Experiments with continuous mode(cw) microwaves of 2.45 GHz indicate that the plasma
density is > 10 11 cm -3. Good radial and axial uniformity are obtained within a 40 mm diameter and along
the length of the chamber (rv400 mm) , respectively.
The low-energy electron temperature, measurable bya probe, lies in the range of 10-14 eV, which is muchhigher than for other high-density microwave plasmas
such as surface-wave or helicon-wave sources.
To further raise the electron temperature and theplasma density, it is desired to increase the power ofthe microwaves. Pulsed mode microwaves are usefulin this regard because higher powers can be obtained.
Moreover , the pulse repetition frequency and the pulse
width provide additional control of the plasma and theextracted beam. We have considered the application

SL

Fig. 1. Schematic of the experimental facility. TR: Trigger signal for pulse initiation, OSC: Magnetron
oscillator, CR: Circulator, TWG: Tapered waveguide, AT: Attenuator, H: Rectangular bend, PM:
Power monitor, M: E-H tuner, INS: Insulator, WG: Rectangular waveguide, W: Quartz window, PL:
Plasma, C: Vacuum chamber, GF: Gas feed, Me: Multicusp, TMP: Turbomolecular pump, EL: Einzel
lens , SM: Sector magnet, SL: Slit, FC: Faraday cup.

200

of high-power short-pulse microwaves. The strong electric fields with a short interval accelerate electrons tohigh energies during the pulse. 8 ) The high electron
temperature persists in the interpulse regime with adecay constant much smaller than those of the charged
particles. This can be helpful for successive ionization
whereby the possibility for obtaining multiply charged
states is increased. The increase in power density inthe narrow tube leads to nonlinear effects such as ponderomotive force and nonlinear dispersion. These effects, together with the anisotropic diffusion of theplasma, are expected to be favorable for increasing thebeam intensity.
The experimental findings in cw and pulsed
microwaves are expected to have great implications in applications where collimated, intense
and multicharged ion beams are required.
We
are currently undertaking feasibility studies of
the above concepts for ion source applications.
Figure 1 shows a schematic of the experimental
system . The design of the vacuum chamber, plasmachamber, microwave circuitry and pumping system
has been accomplished. The components are currently being assembled and the experimental facility

constructed. Ports have been provided on the vacuum
chamber to access the plasma from the radial and axial directions and for beam extraction. Beam intensity
and charge states will be measured. There will be provisions for plasma diagnostics such as X-ray, optical,
probe and electromagnetic field measurements. Investigations will be carried out to obtain an optimized
beam using waves in cw, pulsed or a superposition of
the two modes.
We would like to thank Mr. T. Chiba for assisting
us with the technical drawings. S. B. thanks Dr. H.
Amemiya for his encouragement.
References
1) T. Nakagawa et al.: Rev. Sci. Instrum. 69, 637 (1998).
2) T. Nakagawa et al.: Jpn. J. Appl. Phys. 37, 6215
(1998).
3) C. Perret et al.: Phys. Plasmas 6, 3408 (1999).
4) A. Girard et al.: Rev. Sci. lnstrum. 65,1714 (1994).
5) G. Melin et al.: Rev. Sci. lnstrum. 61, 236 (1990).
6) H. Koivisto et al.: Rev. Sci. lnstrum. 70, 2979 (1999) .
7) S. Bhattacharjee and H. Amemiya: Jpn. J. Appl. Phys.

37, 5742 (1998).

8) S. Bhattacharjee and H. Amemiya: J. Appl. Phys. 84,
115 (1998).

201

RIKEN Accel. Prog. Rep. 33 (2000)

Laser-Plasma Production for Laser Ion Source at RIKEN
T. Takeuchi, T. Katayama, T. Nakagawa, M. Okamura, K. Yano,
T. Hattori,*l K. Sasa, *2 B. Sharkov, *3 and S. Kondrashev*3
In the MUSES project at RIKEN,l) a pulsed-ion
source for highly charged heavy ions is required. A
laser-ion source (1IS)2) is expected to satisfy MUSES
requirements. A test bench at RIKEN is now being developed to investigate the laser plasma for the pulsedion source. A schematic drawing of the test bench isshown in Fig. 1. A TEA CO 2 laser and a YAG laser
are used for producing the laser plasma. The maximum energy and the pulse duration of the TEA CO 2
laser (A = 10.6 J..Lm) are 10 J and 100 nsec, respectively.
A convex BeCu mirror (20¢, 5 t, R = 5 m) and a concave BeCu mirror (50¢, 10 t, R = 10 m) are used as aresonator system for the CO 2 laser. We have obtained
an output energy of 5.7 J using this resonator system
under the gas mixture condition (C0 2 : N2 : He = 1: 1 : 8). On the other hand, the Nd:YAG laser (INDI50, Spectra-Physics; A = 1.064 J..Lm) has a maximum
output energy of 500 mJ and the pulse duration of 67 nsec. The repetition rate is up to 10 Hz for bothlasers. An aluminum target is located in the center ofthe vacuum chamber. The focused laser irradiates thetarget at an incident angle of 36 degrees. The laser
plasma expands perpendicular to the target surface.
Using a streak camera and CCD camera set, one canobtain data of the plasma expansion as a function oftime. We obtained results using the Nd:YAG laser; alaser-produced plasma image using of a 250 mJ laser
pulse is presented in Fig. 2. After about 100 pulses,
the crater shape became an ellipse with a long axis of
700 J..Lm and a short axis of 500 p,m, as shown in Fig. 3.

Fig. 2. Photo of laser-produced plasma of the 250 mJ
Nd:YAG laser.

Fig. 3. Target surface for the 250 mJ Nd:YAG laser.

The power density [W / cm 2] on the target surface canbe estimated as 10 10 W /cm 2 from the size of the ellipse, the laser energy (250 mJ) and the laser-pulse
duration (100 ns). From this value, it is expected thatthe charge state of aluminum ions is at least 3-4. 3)
References

C02 TEA Laser
IOJ. lOOns

Fig. 1. Schematic of RIKEN LIS test bench.

*1

*2
*3

202

Research Laboratory for Nuclear Reactors, Tokyo Instituteof Technology
Tandem Accelerator Center, University of Tsukuba
Institute for Theoretical and Experimental Physics,
Moscow, Russia

1) T. Katayama et al.: Nucl. Instrum. Methods Phys. Res.
A 626, 545c (1997).
2) B. Sharkov et al.: in Handbook of Ion Sources, edited
by B. Wolf, (CRC Press, Boca Raton, 1995), p. 149.
3) R. Scrivens et al.: Rev. Sci. Instrum. 71, 924 (2000).

RIKEN Accel. Prog. Rep. 33 (2000)

Generation of Heavy-Ion Pulses with Short Width andLong Interval
A. Yoneda and T. Kambara
A beam chopping and bunching system has been developed for the generation of nearly single-bunch pulsesof a heavy-ion beam from the RILAC and RIKEN
Ring Cyclotron. With this system, the beam-pulse
frequency can be set to any value between DC and
1 MHz. The source timing signals are sent from either
the control room of the Ring Cyclotron or an experimental site.
Figure 1 shows the system used to generate and monitor the short pulses. A heavy-ion beam is chopped byelectric pulses at a vertical deflector after the 18 GHz
ECR ion source. Then the beam is modulated by asubharmonic RF buncher for time focusing and accelerated by the RFQ linac, RILAC and Ring Cyclotron.
The microscopic time structure of the beam is monitored by secondary-electron monitors before and after
the acceleration by the Ring Cyclotron. In the monitor, the ion beam crosses a tungsten wire which emits
secondary electrons. The wire has a 0.3 mm diameterand it negligibly affects the overall beam characteristics. The secondary electrons are collected by an electrostatic field and amplified by a microchannel plate(MCP). A similar monitor, with aluminum foil for thesecondary-electron emitter, is also set on the experimental beam line (E5A).
The system has been tested with a Xe-ion beam accelerated up to 26 MeV lu. The accelerators were operated at a frequency of f = 28 MHz. The chopping voltage at the deflector had an amplitude of about 500 V,

SecondaryElectron
Monitor

SecondaryElectron
Monitor~~_

ESA
Beamline: I lL 'l
Beam onFig. 1. Generation and measurement systems of short beampulses.

~-O.2

~-0.4
:::s

o

~ -0.6u~ -0.8;:;.9<-0.4:::s

Expandedo[) -0.6~ -0.8~5~0~~~500~~~~55~0~~~600
Time (ns)Fig. 2. Time structure of t he beam bunch.

width of 250 ns for beam ON and interval of 25 ms.
The subharmonic buncher was operated at a frequencyof f 17. The time structure, shown in Fig. 2, was obtained at the E5A beam line. The highest peak had awidth of about 3 ns. The additional periodical peaks
with an interval of about 35 ns were microbunches,
which were not collected by the sub-harmonic buncher.
A relatively high peak later than the main peak by
about 320 ns (9 x microbunch period) was a microbunch extracted from the cyclotron one turn later
than the main bunch (the harmonic number of the
Ring Cyclotron was 9). The number of ions in a pulse
was estimated to be in the range of 10 4 . . The beamleakage, that is the beam intensity in the OFF status,
was lower than 10- 4 of that in the ON status.
This system has been successfully used in experiments reported elsewhere. 1 }References
1) T. Kambara et al.: Nucl. Instrum. Methods Phys. Res.
B (2000), in press.

. I

20~

RIKEN Accel. Prog. Rep. 33 (2000)

A Plan for- a New Control System for the RIKEN Ring Cyclotron
Using EPICS
M. Kobayashi-Komiyama, M. Kaji,*l M. Nagase, 1. Yokoyama, T. Tanabe, M. Sugimoto,*2 and M. KaseWith regard to the control system of the RIKEN
RI beam factory (RlBF) project,l) it has become necessary to expand the present control system of the
RIKEN ring cyclotron (RRC) to maintain compatibility with the RIBF project. Therefore, we are searching for the optimum means of extending the present
system to improve its compatibility. In this paper, we
report a plan which uses the Experimental Physics andIndustrial Control System (EPICS). 2)
Figure 1 shows a block diagram of the present control system of the RRC. It has been more than 13 years
since system operation was started. The main concerns
regarding this system are as follows:(1) A host computer (minicomputers, Mitsubishi
M60/500) is the only brain in the present control system. As a result, it plays many roles in the system. These roles include the operator interface, input/output control and data storage (which are theparameters of RRC operation). In order to aid in
the tasks of the host computer, intelligent modules
are used for the interface between CAMAC modules
and control devices. Two types are used: one is a CAMAC module called a communication interface module(CIM), and the other is a terminal module for highspeed local control of accelerator devices, called a device interface module (DIM). Both module types weredeveloped in our laboratory. The details of these modules are given in Refs. 3 and 4. As there is an expan-

sion limit to the control ability of this system, it is notsuited for expansion.
(2) The components of the system have become old.
Thus, the system maintenance cost has become high.
The age of the touch panel in particular has become aserious problem. Most man-machine interactions are
performed using the touch panels: however, sometimes
they do not respond during beam operation. Replacing
the panels with new ones would require developing new
applications; this would not be easy in any respect.
(3) Both control data and logic are written in thesame application code. In other words, the current
control system does not separate control data andlogic. This type of system is not suited for extension.
In order to solve these problems, a plan for an alternative new control system of the RRC using EPICS
was proposed last year. We employed part of the alternative system this year as a preliminary test.
The EPICS is the distributed supervisory control
system which has many servers (usually on VMEbus).
Present and future developments are being carried out
cooperatively by the EPICS collaboration, originallydeveloped by ANL and LANL. Currently, the collaboration is expanding and now includes several laboratories around the world (not only in the US). The
real-time operating system VxWorks runs on the VME
computers. As shown in Fig. 2, the operator interface(OPI) and input/output controllers (lOCs) are connected using Ethernet, and thus the number of IOCs
is not limited. Therefore, the EPICS is suited for large

Optical Dataway

Ethernet

CAMAC Serial Highway
Highway
U Port400m
Optical Fiber '--------;?""ok-'

CAMAC Serial Highway

CAMAC Serial .-------, r - -.............----,
Highway
UPort400m
Optical Fiber

Power
SupplyUnit

Diagnostics

Power
SupplyUnit

Fig. 1. The present control system of the RRC.
Diagnostics
.. 1
.. 2

204

Mitsubishi Electric Corporation
Mitsubishi Electric Control Software Corporation

Fig. 2. The new control system using the EPICS .

Table 1. Comparison between- the M~O computer system and the EPICS.
<Hardware>
ComputerPresent System

New EPICS

Minicomputers M60

Network

CAMAC Crate Controllers
CAMAC Serial Highway(UDP Optical Fiber)

Operational Screen

Character-Based Touch Panels<Software>OS

M60: OS60/UMX

Middleware
Control Logic

None
Fortran Programs

VME Computers (for I/O Controller)
EWSs (for Operator Interface)
CAMAC Crate Controllers
CAMAC Serial Highway(UDP Optical Fiber)
Ethernet (between EWS and VME)
Graphic User Interface (Motif-Based Windows)

Present Systemprojects such as the RIBF when we take into consideration the cooperative development and control of many
accelerators. The EPICS has been used at a numberof sites not only in particle accelerators and telescopes
but in general enterprises at more than 70 sites aroundthe world. Furthermore, use of the EPICS is free forpublic research institutes.
The replacement plan using the EPICS is shownin Fig. 2. The M60 computer system is removed
and VME computers and engineering workstations(EWSs) are installed in its place. Software on t he M60
computer system is replaced by the EPICS and an Oracle (a relational database management system)- based
software system. In the new control system , we plan tostore all accelerator system data using in Oracle. This
enables the sharing of data between users and prevents dual storage of the control data. This databasemanages the properties of the control devices such asdevice name, control address and specifications. As
shown in Fig. 2, the remaining components, including
the CAMAC loop , are not replaced. Taking into
consideration the fact that the RRC is in operation,
we plan to replace the M60 computer system and the
man-machine interface components first , so as not tosignificantly influence the RRC operation. However,by replacing the M60 computer system with EWS andVME computers, the present equipment is expected
to realize maximum control ability. A comparison

New EPICS
VME: VxWorks 5.2 (Included by Tornado 1.0)
EWS : HP-UX 10.20
EPICS R3. [3, Oracle Workgroup Server 8.0
EPICS DevicelDriver Supports (Low Level)
EPICS Database (Middle Level)
EPICS Cli ent Applications (High Level)

between the present system and the new system isshown in Table 1.
We have tested the preliminary system for controlling the power supplies, profile monitors and Faraday
cups of the RRC. The graphic user interfaces (GUIs)for controlling the above equipment were prepared, andthey exhibited the same responses as the current system. Furthermore, the access speed between the OPI
and the DIM was 30 times faster (3 ms) for each accessin the new system; this speed is very fast and we expect smoother operation because of this. However , thetest situations differed between both systems, so an
accurate comparison of the two may not be possible.
Therefore, it has been verified that fundamental operations can be performed using the preliminary system. From this point , the development of the control
system replacement will continue and the actual replacement will be performed.
References
1) Y. Yano et al.: Proc. 15th Int. Conf. on Cyclotrons andTheir Applications 1998, Caen, p . 696 (1998).
2) L. R . Dalesio et al.: Proc. Int.Conf. on Accelerators and Large Experimental Physics Control Syste.m s(ICALEPCS' 93), Berlin, p. 179 (1993).
3) T . Wada et al.: Proc. 11th Int. Conf. on Cyclotrons andTheir Applications, Tokyo, p . 407 (1987) .
4) T. Wada et al.: IEEE Trans. Nucl. Sci. NS-32, 2095
(1984).

205

RIKEN Accel. Prog. Rep. 33 (2000)

Low Power Test of CSM Resonators
O. Kamigaito, M. Kase, Y. Miyazawa, T. Chiba, N. Sakamoto, M. Hemmi,
s. Kohara, E. Ikezawa, A. Goto, and Y. Yano
The resonators of the first unit of the Charge-State
Multiplier (CSM)l) have been constructed and low
power tests were carried out.
Table 1 summarizes the design parameters of thefirst unit. It consists of two acceleration tanks andone deceleration tank, each of which has eight rf-gaps
with a maximum gap voltage of 450 kV. The resonant
frequency was chosen to be twice the fundamental frequency; it varies from 36.0 to 76.4 MHz. The designed
voltage-gain of each tank is about 2.9 MV over theentire frequency range.
The resonator structure of the first unit is illustrated
in Fig. 1. It is based on a A/4-coaxial resonator witha movable shorting plate. By using the computer code
MAFIA , the shape of the stems as well as the size of thecoaxial part were optimized so that the current density
on the sliding contact would be as small as possible.
In the final design, the current density is estimated to
be 60 A/ cm at the maximum gap voltage.
All three resonators have the same dimensions except for the drift tubes and the stems. The rf-poweris fed through a capacitive feeder. A capacitive tuner
is used for the fine tuning of the resonant frequency.
Each resonator is equipped with a cryogenic pump of
4000 l/s and a turbomolecular pump of 500 l/s.
Cooling is one of the most significant problems associated with these resonators. According to the calculation, the maximum power loss in each end-stemamounts to 9 kW. Therefore, the arrangement of thecooling channels has been carefully designed based on
the heat analysis. The maximum displacement of thedrift tubes due to thermal deformation is estimatedto be 0.06 mm in the vertical direction. Taking theseanalyses into account , the drift tubes have been alignedwith an accuracy of ±0.15 mm in the transverse direc-$500; Shorting
Plate

Fig. 1. Schematic diagram of the resonator of the firstunit . Dimensions are given in mm. All components ofthe three resonators are the same size except for thedrift tubes and stems.

tion and ±0.3 mm in the longitudinal direction.
Figure 2 shows the resonant frequency of the fundamental mode in the first acceleration tank. As shown in
the figure, movement of the shorting plate by a strokeof 1300 mm varies the resonant frequency from 34.8
to 81.5 MHz. The measured results are in good agreement with the MAFIA prediction. Similar results havebeen obtained in the other two resonators. We havealso seen that the capacitive tuner changes the reso90

80

Table 1. Designed parameters of the first unit.
Tank
Frequency (MHz)mlq
E in (MeV lu)
E out (MeV lu)
N umber of gaps
Gap voltage (kV)
Synchronous phase
Bore radius (cm)
Inner length (m)Power loss (kW)b.d
Zs (MS1/m)c.d

Accel.2
36.0-76.4
24.7 a-S .Sb
O.76 a-3.43 b
O.88 a-3.96 b
450

Decel.
36.0-76.4
12.0a_2.7 b
0.88 a- 3.96 b
0.65a-2.91 b
8
450

- 25°

+ 25°

1.75
1.3
61
152

1.75
1.3
58
146

8

a : At 36.0 MHz (lowest frequency)

b: At 76.4 MHz (highest frequency)
c: At 54.4 MHz d: MAFIA prediction

206

N::r: 70

Acce1.1
36.0-76.4
24.7a -S.S b
0.65a- 2.91 b
0.76 a-3.43 b
8
450
- 2S0
1.75
1.3
58
147

Front View

Side View6t"> 60~~~~t------I-.

I- - ---MAFIA ~_I --.- Measured

I

I '~
I
~-.-- - -----t--B::3
g 50 d::40 ~-~_' l~ ~

II~ ~":::i

600

800

~

~ ~ ~ ~ ~

I

30

1000

1200

1400

1600

1800

Position of shorting plate (mm)Fig. 2. Measured resonant frequency of the first acceleration tank (solid line) along with the MAFIA calculations (dashed line).

3

1-•

30000 I---__'""'-::::::t:-I------+----~ ----_t__----'='_i_--_I

Measured
MAFIA

I
~

25000 I-----l-- --I----.+---+---+--~.,..,.....ri=F::"I---e""!!~~~~_...-.....=-...-~....
~;;;;;;--:-",,~+I-.-G)~ 20000

-

-

J)

-

~

_-----------;>& 15000 f - - - -.- c - - - --I--..- --- j - - - - - j -- - -- + - - --!

~- - . 70%MAFIA- - - -. 60%MAFIA--.---. --+- Measured ~

~ ~
--'

o ~~~~~~~~~~~~~~~~~~
30

40

50

60

70

80

o

-

__ J
o

90

nant frequency more than 0.5% in the whole frequency
range.
The second and third higher modes appear around
100 and 150 MHz, respectively. These frequencies arewell reproduced by the MAFIA calculation.
The measured Q-values of the first acceleration tankare shown in Fig. 3 along with the MAFIA calculations. As shown in the figure, the measured values arearound 20000. They are approximately 63-71 % of thecalculated ones. The results for the other tanks arequite similar to that observed for the first tank. By
comparing these results with the MAFIA calculations,the maximum power loss is estimated to be 90 kW.
We also measured the parallel shunt resistance (Rs)of the first tank by using the calibrated pickups of theresonator. Rs is related to the power loss P and thegap voltage V by P = V 2 / (2Rs). The obtained values are about 1.5 MO over the entire frequency range,
which gives the power loss of only 70 kW at the maximum gap voltage. It is known, however, that this measurement overestimates Rs; an estimation given by the
Q-value above would be more reliable.
Figure 4 shows the electric-field distribution of the

.,

.

I
I

20

- .-~~~_

J~...- -'--~.

-- .--

-.~

-I
•-,

~

30

40

50

•

U
60

70

l~

I-

rr

••l
I

80

90

100

110

120

r-..-

~

130

Z (em)

Frequency (MHz)Fig. 3. Measured Q-values of the the first acceleration tankalong with the MAFIA calculations. The dashed curvesindicate the calculated values scaled by 70 and 60%.

JO

I

I

10000 1--- -1- - - - - ' .------- . - .--- - - MAFlA
5000 ~-.- -.-------. ----- --- --------\ij

Fig. 4. Electric-field distribution on the acceleration axis
measured for the fundamental mode at the lowest frequency (34 MHz). The solid curve indicates the measured data. MAFIA prediction is indicated by closed
circles.

fundamental mode on the acceleration axis, which wasmeasured by means of a perturbation method. Since
the gap length is long, the field strength is minimum atthe center of each gap. Moreover , the strength on theupper drift tubes is larger than that on the lower ones,
which reflects the vertical asymmetry of the resonatorstructure. These results are well reproduced by the
MAFIA calculations, as shown in the figure.
The power amplifiers have already been fabricatedbased on a tetrode tube, SIEMENS RS2058CJ. The
output power of 100 kW has been successfully achieved
over the entire frequency range required for the operation. Details of the amplifiers are given in Ref. 2.
The three tanks will be installed in the RILAC building within the next year. Acceleration tests will be
carried out after high power tests using the amplifier.
References
1) O. Kamigaito et al.: Proc. 12th Symp. on Accelerator
Science and Technology, Wako, p. 233 (1999).
2) Y. Murakami et al.: Proc. 12th Symp. on Accelerator
Science and Technology, Wako, p. 239 (1999).

207

RIKEN Accel. Prog. Rep. 33 (2000)

Construction of the IRC for RIKEN RI Beam Factory
T. Mitsumoto, A. Goto, M. Kase, J. Ohnishi, O. Kamigaito, N. Sakamoto, K. Ikegami, K. Sugii,
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 is
utilized for the RIKEN RI-Beam Factory. It will be
installed as the intermediate stage between the existing RIKEN Ring Cyclotron (RRC) and the Superconducting Ring Cyclotron (SRC).l) 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 is126.7 MeV/nucleon and 4.57 Tm, respectively.2)
Figure 1 shows a plan view of the IRC, which consists mainly of four sector magnets, two main RF resonators, one flattop resonator, and injection and extraction devices. The main components of the IRC are
installed in an area of 14 meters square.
The IRC will be operated at a harmonic value of 7,
while that of the RRC is 9. Thus, the injection radiusof the IRC is determined to be 7/9 of the extraction
radius of the RRC. The main parameters of the IRC
are listed in Table 1.
The fundamental structure of the sector magnet of
the IRC is similar to that of the RRC. The main coilsof the sector magnets are designed to be of a low power
consumption type. The maximum power of the main
coils is suppressed at 70% of that of the RRC, although
the maximum magnetic field is higher than that of the

I~

14000

~///
E8M2

Table 1. Main parameters of the IRC.
980 MeV
4

K-value
Number of sectors

7

Harmonics
A verage radius
Velocity gain factor
Number of cavities

Injection

2.77 mExtraction

4.15 m

Main

1.5
2

Flat-top
Cyclotron frequency

2.57-5.45 MHz

RRC. The temperature increase of the cooling water
due to the main coils is calculated to be less than 10 degrees.
Manufacturing of the sector magnets is in progressat the Niihama works of Sumitomo Heavy Industries,
Ltd. The machining of yoke plates and poles for four
sector magnets has already been completed. Figure 2
shows a photograph of the lower yoke of the first sector
magnet (E-sector) being assembled. Figure 3 shows themain coil of the sector magnet.
The first sector magnet will be completed in February of year 2000. Magnetic field measurement of thesector magnet will start from March of year 2000.
Firstly, measurement for one sector magnet will be performed. After that, two sector magnets will be alignedwith a configuration that is the same as the actualone. Then, field mapping of a 180 degrees region will
be performed in order to measure the coupling effectof the sector magnets. The field mapper of the IRC isdesigned to be able to measure 360 degrees mapping_: /1:~BM1w-

E-

s-

Fig. 1. Plan view of the IRC.
Sumitomo Heavy Industries, Ltd.

208

Fig. 2. Lower yoke of the E-sector magnet being assembled
at Niihama works, Sumitomo Heavy Industries, Ltd.

Fig. 3. Main coil tor the sector magnet.

Fig. 4. Main resonator of the IRC.

after installation of the entire sector magnets into the
RIKEN site.
Two types of resonators are adopted for the IRe:
Two main resonators and one flattop resonator. The
main resonators are of a single-gap type with flapping
panels for changing the resonant frequency.3) Figure 4
shows the stainless steel wall of the main cavity being
constructed. The flattop resonator is of a single-gap
type with shorting plates. In order to realize ultrahigh vacuum, a duplicated-wall structure is adopted. 4)
Manufacturing of the main resonators has been

started and will be completed in the summer of 2000.
References
1) Y. Yano et al.: Proc. 1997 Particle Accelerator Conf.,
Vancouver, 1997, p. 930 (1998).
2) T. Mitsumoto et al.: RIKEN Accel. Prog. Rep. 32, 195(1999).
3) N. Sakamoto et al.: Proc. 12th Symp. on Accelerator
Science and Technology, Wako, 1999, p. 224 (1999).
4) T. Hiasa et al.: Proc. 12th Symp. on Accelerator Scienceand Technology, Wako, 1999, p. 293 (1999).

209

RIKEN Accel. Prog. Rep. 33 (2000)

Model Test of the RIKEN-IRC* Main Resonator
N. Sakamoto, O. Kamigaito, Y. Miyazawa, T . Chiba, A. Goto, and Y . Yano
The intermediate-stage ring cyclotoron, IRC, whichis the first stage booster in the RIKEN RI beamfactory,l) consists of four normal conducting sector
magnets, two acceleration resonators and one flat-top
resonator. 2) The frequency range of the acceleration
resonators is from 18.0 to 38.2 MHz. In order to obtaina sufficient turn separation as large as 6 mm at the extraction orbit , the acceleration voltage is required to be
1.2 MV /turn in the case of 38.2 MHz operation. The
acceleration resonator is a single-gap-type resonator
whose structure is basically the same as that of the
Research Center for Nuclear Physics (RCNP), Osaka
University, ring cyclotoron. Its geometrical design has
been optimized using a three-dimensional rf calculation
code, MAFIA.3 ) In order to determine the accuracy ofthe calculated frequencies and the Q-values in comparison with the theoretical ones, a 1/5 scale model
was built and test measurements were performed. A
theoretical Q-val ue of the model is 1/ J5 that of the actual resonator , while a resonant frequency is five times
higher.
A schematic drawing of the model is shown in Fig. 1.
A resonant frequency of the resonator is tuned by flapping two panels which are located symmetrically on the
median plane. The calculated rf characteristics of themodel are shown in Table 1.
In order to evaluate the Q-values accurately in comparison with the calculated ones, the mechanical designof the model was carefully carried out to simulate thestructure of the actual resonator. To know the realistic
760mm
360mm

Table 1. The calculated resonant frequencies and Q-values
using MAFIA.

o deg.

Flapping panel
Frequency
Q-value

89.8 MHz
12970

90 deg.
193.6 MHz
16550

Q-values is crucial in determining the rf power and thecoupler size of the actual resonator.
The conductive parts of the model were made ofcopper. The contact fingers and contact strips wereused to reduce the resistivity between the conductive
parts. The overall geometrical misalignment was lessthan 0.3 mm. The rf power was fed using an inductive
coupler which was located at the center of the rear wall,as shown in Fig. 1. The resonant frequencies and the
Q-values were measured using a network analyzer with
an S-parameter test set (HP8753E). Two pickup loops
were used , one for excitation and the other for detection. These loops were identical and were very weakly
coupled to the resonator. Figure 2 shows the measured
resonant frequencies and Q-values. The measured resonant frequencies were slightly high in comparison withcalculated values (compare Tables 1 and 2). The Qvalues were as large as 63- 71 % of the calculated values.
The coupler was an inductive type whose coupling
could be varied by changing the cross section of theloop. A schematic drawing of the coupler for themodel is shown in Fig. 3. A characteristic impedanceof the coaxial part was set to be 50 n. By sliding thecoupler position I = 14- 35 mm, the input impedanceof the resonator could be matched to 50 n and the

270mm

E
E

~

M

N

::r:

90 deg,Q- factor_ x - -K - - 'X
-* -

200
X

175
/

I

150

Q)

J.-.

~

,,(

I
I

x

::i
0'
Q)

0
/

;<

:>-.
s:1

10000

/0

/

~
()

AJ

/x

X
/

X

/

'"

/

10
I

~
c:

10

/

CD
Vl

0
/

125

7500

/
/

pJ
I

100

,1- -- -- .- .- .- -- -- ,- -- ,- ,- .- . - ,--- -, - ,- ,- ,- ,- ,- ,-

o
75

o

(16,0 MH )

20

40

60

80

5000

Tuning Panel Position [deg.]
Fig. 1. Schematic drawing of the 1/5 scale model.
Intermediate-stage Ring Cyclotron

210

Fig. 2. Measured resonant frequencies and Q-values for the
1/5 scale model.

Table 2. Measured resonant frequencies and Q-values atthe panel angles of 0 deg. and 90 deg.
Flapping Panel
Frequency
Q unloaded
loadedo deg.
91.69 MHz
8190 (63%)
4190

1.0

o deg.

90 deg.
196.05 MHzxx

11710 (71%)

5840

N umbers in parenthesis indicate the ratio to thetheoretical values listed in Table 1.

)!(

x

0 .9

):(
)!(

Ii

tl

f::
~

X

x 0 deg . (90.003 MHz)0}:(30 deg. (139.575 MHz)'-.....
~)!(

x 60 deg. (174 .284 MHz)

x

0 .8

090 deg. (196 .343 MHz)
x
0

-

MAFIA

90 deg.

200

300

400

Position x [mm]Fig. 4. Gap voltage distribution. Curves were obtainedusing MAFIA.

Matching

0° 1 = 35

90

0

1= 14
N ConnectorU

gap voltages were obtained , as shown in Fig. 4. The
voltage distribution was found to be in good agreement with the MAFIA calculation. According to theresult of the frequency measurement, a gap size between the flapping panel and the dee surface at thepanel position of 0 deg. was reduced by 5 mm (original 100 mm ~ new 95 mm) so as to reduce the lowest frequency. The size of the coupler was decided tobe five times larger than the model coupler, that is,
the margin of the coupling size is about 50%. The
results of the model test are being considered in thedesign of the actual resonator which is now underconstruction.

Fig. 3. Schematic drawing of the coupler.

8 11 was less than -50 dB for the entire frequency
range. The loaded Q-values were almost 50% of theunloaded ones (see Table 2). A measurement of theelectric field distributions was performed using the
perturbation method. A spherical field perturbator(3/8" ¢) made of Teflon was used. By integrating
the field strength distribution along the beam orbit,

References
1) Y. Yano et al.: Proc. 1997 Particle Accelerator Conf.,
Vancouver, 1997, p. 930(1998).
2) N. Sakamoto et al.: Proc. 15th Int. Conf. on Cyclotrons
and Their Applications, Caen, 1998, p. 223(1999).
3) The MAFIA Collaboration, User's Guide MAFIA Version 4.0, CST GmbH, LauteschagerstraBe 38, D-64289,
Darmstadt, Germany.

211

RIKEN Accel. Prog. Rep. 33 (2000)

Status of the SRC for the RIKEN RI Beam Factory
A. Goto, H. Okuno, T. Kawaguchi, J. Ohnishi, T. Mitsumoto, T. Tominaka, S. Fujishima,J. W. Kim, K. Ikegami, N. Sakamaoto, K. Sugii, Y. Miyazawa, O. Kamigaito,
M. Kase, T. Wada, T. Morikawa, T. Chiba, and Y. Yano
The layout of the SRC (Superconducting Ring Cyclotron) has been changed from the previous design, as
shown in Fig. 1. The changes are as follows.
(1) Injection and extraction are carried out in thesame valley chamber.
(2) An electrostatic inflection channel (EIC) and anelectrostatic deflection channel (EDC) are set in opposite valley chambers, so that the injection beam does
not pass through holes of both channels but only thehole of EIC.
(3) The flat-top resonator is placed beside one of thefour acceleration resonators in the same valley chamber.
Fabrication of the prototype sector magnet is continuing. As of December 1999, both the upper andlower cold masses, including main coils, trim coils andpoles, have been completed. Figure 2 shows a photograph of the upper and lower cold masses that havebeen preliminarily assembled. The cryostat is nearlycomplete and the assembly of the cold masses in thecryostat is about to start. Lower and side yokes havebeen installed at the factory test site. Scheduling of a

Fig. 2. Photograph of upper and lower cold masses thathave been preliminarily assembled.

test of the prototype sector magnet has been delayed
due mainly to the electrical shorts in the main coil;a cool-down test of the entire system, as well as themeasurement of magnetic fields, has been rescheduled
to take place by the summer of 2000.

Sector Magnet

Fig. 1. Plan view of the redesigned SRC.

212

Connecting Plate

Welding

Upper Pole

Coil Vessel

Lower Pole

CotterFig. 3. Cross-sectional view of the main coil, coil vessel andcold pole.

We encountered some serious problem in the courseof the fabrication of the prototype sector magnet; electrical shorts were found in both the upper and lower
main coils when the coil winding was almost completed, as well as in the trim coil. For details, see
Ref. 1. We have made a major change in the methodof fixing the main coil vessel to the pole of the prototype sector magnet . The "hooks" anchoring the main
coil vessel to the pole in the upper cold mass have been
replaced by two connecting plates covering the surfacesof the pole, as shown in Fig. 3.
The second international technical advisory committee (TAC) for the review of the sector magnet was heldin May 1999.
Design and/or R&D of other components of theSRC, such as a superconducting injection channel andan rf resonator, are also being carried out. A prototype of superconducting inflection channel MIC2 isbeing fabricated, and will be tested in the prototype
sector magnet . A 1/5-scale model of the resonator for
the IRC, which is quite similar to that of the SRC, wasfabricated and tested. A coaxial rf resonator has also
been produced in order to develop rf contacts that canendure high current density.
References
1) T. Kawaguchi et al.: RIKEN Accel. Prog. Rep. 33, 214(2000) .

213

RIKEN Accel. Prog. Rep. 33 (2000)

Development and Construction of the SRC Sector Magnets
T. Kawaguchi, H. Okuno, A. Goto, J. Ohnishi, T. Tominaka, T. Mitsumoto, and Y. Yano
Six superconducting sector magnets 1 ) are to
be incorporated into the superconducting ring
cyclotron(SRC)2) for the RIKEN RI beam factory. A
full-scale prototype magnet 3 ) is currently under construction. The construction status of the prototype at
December 1999 is as follows: Two sets of the superconducting main and trim coils were completed; thevacuum vessel was completed; the 80 K thermal shieldis under production; 14 sets of the thermal insulating support rods for fixing the coil position were completed; a group of sliced plates for the yoke, with a
total weight of 730 tons, was completed and is now
being assembled at a cold test facility. The assembly
and the cooling/excitation test of the prototype will
be completed in the spring and summer of 2000, respectively.
During prototype construction, we experienced someproblems . The first problem was the occurrence ofelectric turn-shorts in the main coils. In the lower
main coil , turn-shorts were found at 12 points after
the closing of the bolt-type vessel. 3 ) Uncoiling of theshorted lower coil and rewinding using the same superconducting wire were adopted as a remedy. As a result ,it took another four months to obtain a satisfactorycoil. Upon the uncoiling, all of the turn-shorts wereobserved in both turn-transition and layer-transition
regions shown in Fig. 1. We concluded that the turnshorts occurred because of the following causes. (1)The transition regions of the wire, initially formed into
the designed shape by a forming tool, were stretchedand deformed by winding tension. (2) The local coilsize at the transition regions became larger than thesize at the normal region due to the unmatched transition shape. (3) Coil pressing of the lower coil was
carried out so as to obtain the same coil size. Thus,
the transition regions were over pressed and some of
the transition regions made the turn-shorts. The imLA YER TRANS ITION
NO .1 LAYER

NO .1 LAYER
NO.2 LAYER .//,%/ -----~~ ~>SI//NO .2 LA YER

':;"
g

/~

TURN TRANS ITION\'~'''''''

proved items applied to the lower coil are as follows.
(1) The transition regions of the wire were initiallyover formed with a change of the forming tool shape,
so as to be of the designed shape after the application of winding tension. (2) The winding tension was
decreased from 260 kg to 170 kg. (3) The electric insulation of the transition regions was reinforced. (4)A continuous electric inspection was performed during the entire winding process. These improvements
should be applied to the serial production of the SRC
sector magnets.
In addition to those in the main coils, turn-shorts
were found at two points in the upper coil after the
final welding of the upper coil vessel. The upper coil
was wound by a different company than the lower coils.
The shorts were also located in the transition regions.
The repair of the shorts was carried out by inserting
additional insulating film between the shorted turns
through two holes which were drilled in the coil vessel
for the repair.
The second problem was regarding the structure design of the weld-type upper coil vessel. The maximum
stress at the "Hook-connection" 3) in the cold-pole wascalculated to be 370 MPa against the main coil's electromagnetic force. On the other hand, the measured
result of the fatigue strength of pure iron which wasused as the cold-pole material, showed the minimum
strength to be 510 MPa after 10000 cycles of load at
78 K. The safety factor of 510/370 = 1.34 was muchless than our criterion of 2.0. After some studies anddiscussions, the connection structure of the prototype
was finally changed to the "Connecting-plate" shownin the figure of Ref. 4.
The third problem was again turn-shorts, this timein a trim coil. These shorts were caused by the me-

LA YER DIRECTION.,../' -Ci, ~\~~ =s------------~,:
... ,

4

-

-

LAY ER TRANSITION

NO.3 LAYER

/

I

\.

NO.1 LAYER

NO .2 LAYER

NO .3 LAYER

Fig. 1. Schematic drawing of the transition regions in themain coil winding.

214

Fig. 2. The proto-trim-coil vessel after the closing weld.
The numerous circular marks indicate the stay-rod
welds.

Table 1.
Comparison of the calculated and measured results of the unbalanced magnetic forces at
6 MA/magnet in the case without trim coils.
DIrection

Arrangement

Calculated

MeasuredRadialRadialRadialI-sector
3-sector
6-sector-56 tons
Not calculated
100 tons-30 at 4.5 MA' * 1
37 tons
72 tons *2

I-sector

7 to 12 tons/mm 8 tons/mm *3

I-sector
3-sector

Not calculated
Not calculated-_.

Vertical'--AzimuthalAzimuthalFig. 3. The three-sector arrangement of the 1/6-scale test
magnets for the magnetic force measurement.

chanical deformation of the trim coil vessel due to thestay-rod welds shown in Fig. 2. Many turn-shorts were
found in one of the six sub-coils. In the end, this one
sub-coil was electrically bypassed to allow the use of
the five sound sub-coils. As the basic improvement forthis problem has not yet been applied to the prototrim-coil, the solution should be studied before the
manufacture of the SRC sector magnets.
Other R&D works are mainly as follows.
(1) Measurement of the unbalanced magnetic forces
Three sets of 1/6-scale Cu/lron magnets were fabricated, and the unbalanced magnetic forces between thecoil/pole and yoke were measured in both one-sector
and three-sector arrangements. Figure 3 shows a photograph of the three-sector arrangement. These test
magnets were cooled to 78 K and excited in pulse forl .to 2 seconds. The maximum magnetic field reached
4.0 T, which corresponds to 90% of the maximum valueof the actual superconducting sector magnet. The
measured results can be converted to the value for the
full-scale magnet by using a scaling law. Table 1 shows
the converted values in comparison with the calculated
ones.
(2) Estimation of the eddy current loss in the coldpole
For the study of the thermal effects on the helium- 0.8 ton/mm *3-0.15 ton/mm *3*1 The maximum occurred at 4.5 MA in the measurement.
*2 This is an estimated value from the three-sector measurement.
*3 Plus indicates decentering and minus recentering force.

cooling system,I) the eddy current loss in the cold-poleat the time of magnetic field change was estimated.
The electric resistance of pure iron was measured at
4.2 K in 0 to 4 T, and a value of 1.0 x 10- 8 to 1.2 X
10- 8 Ohm-m was obtained as the specific resistance.
Using this resistance number, the eddy current losses
under two conditions were calculated. In the case ofcurrent ramping from a A to 5000 A (corresponding to
4.5 T) in 2 hours, the average eddy current loss wascalculated to be 22 W per magnet. Also, in the caseof current break with a time constant of 52 seconds for
emergency safety operation at the magnet failures suchas coil quench, the total loss during the current break
was calculated to be 4 MJ per magnet. This value
corresponds to 6% of the total magnetic stored energyof 65 MJ. These estimated values are not thought tobe a cause of serious problems for the helium coolingsystem.
References
1) T. Kawaguchi et al.: RIKEN Accel. Prog. Rep. 32, 201(1999).
2) A. Gotoetal.: RIKEN Accel. Prog. Rep. 32,193 (1999).
3) T. Kubo et al.: RIKEN Accel. Prog. Rep. 31, 210(1998) .
4) A. Goto et al.: RIKEN Accel. Prog. Rep. 33, 212 (2000).

215

RIKEN Accel. Prog. Rep. 33 (2000)

Quench Analysis of Stagnant Normal Zone in the RIKEN
Prototype Sector Magnet
J.-W. Kim, A. Goto, and Y. Yano
The prototype sector magnet under construction at---RIKEN is designed to be cryostable with cooling bypool boiling. However, a quench may occur when conditions for cryostability is not met in the actual coilvessel. A likely quench scenario in a cryostable coil, besides accidents and unexpected quenches, is that heatgeneration larger than critical quench energy initiates
a quench in a poorly cooled region where a section of
conductor is exposed to helium vapor.
The effects of existence of uncooled conductor werestudied using the one-dimensional heat diffusion equation. It is assumed that a normal conducting region is
initiated in the 2L long section of uncooled conductor,
and that the initial normal conducting region has no
cooling throughout the quench propagation. The equation has a symmetry point at zero of the x-coordinate
along the conductor length as given by
C(T)A

oT

0 ( K(T)A aT).
ox + ~(T)2p(X, T),

Eit = oxx < L, (1)

C(T)A

aT

a ( K(T)A aT)
ax + i(T)2p(X, T)

Eit = axx > L,-h(T)(T - Tb),(2)

where C(T) is the specific heat of conductor, K(T) is
the thermal conductivity, A is the cross sectional area,p(x, T) is the resistivity, h(T) is the heat transfer coefficient between the conductor and LHe, and Tb is the
LHe bath temperature. The temperature distribution
corresponding to a normal conducting domain is plotted in Fig. 1. It is prescribed in the ohmic heatingterm i(T)2p(X, T) that the sharing of current in thetemperature range between Tb and conductor criticaltemperature Te is linear with temperature. I) The heattransfer is thought to be static because of the slow
propagation of normal conducting region in the poolboiling coil.
Because the cooling can deteriorate also in the regions outside the initially uncooled section, degradation of the cooling was taken into account by adapting cooling efficiency (t) to the heat tr ansfer term as
th(T)(T - Tb). The resultant partial differential equations were solved using the NAG Fortran Library employing a finite difference method.
There is a minimum uncooled length of the conductor, beyond which a normal conducting region can
propagate at small perturbations, i.e. in the order of
10 4 J 1m 3 for the conductor of the prototype magnet.
Critical lengths of the uncooled conductor (Le) were
calculated as a function of t at the maximum excitation with a current of 5 kA as shown in Fig. 2. If
the uncooled section is shorter than the critical length,
minimum quench energies are appreciably high, so thatquench is normally unexpected. When L is shorter
than L e , T m 's are plotted in Fig. 3 for two given cooling efficiencies 1 and 0.5. The minimum quench energies are in the order of one hundred J, and the energy
densities are over 106 J 1m 3 , which are considered sufficiently large for the coil to be cryostable.
Figure 4 shows quench propagation initiated from a
section of the uncooled conductor slightly longer than
Le. The cooling efficiency is set to be 0.5. It is clearlyshown that the normal zone propagates slowly, namely
a growing stagnant-zone is established. Part of the
conductor is then overheated. Quench detection using

60+---~--J---~--J---+

50
T

40

normal

30
u

-1

20
10
o~--~--~----~--~--~

0.0
L

x

Fig. 1. Temperature distribution in a normal conducting
domain used for the heat diffusion equation.

216

0.2

0.4

0.6

0.8

1.0

Cooling efficiency (e)Fig. 2. Critical lengths of the uncooled conductor versus
cooling efficiency.

100
80

....-- 60~..--...

~=1.0'---'"

E

I-

60

~

'-" 50
Q)

~ 40
o

+-'

40

l:=0.5

~ 30
0.

E
20
Q)

20

I-

0+--.--.--.-.,-.--.--.--.-.--+

10o 5 10 15 20 25 30 35 40 45 50
50 100 150 200 250 300 350
Length (em)L (em)
Fig. 3. Temperature at the center of the normal conducting
zone as a function of uncooled conductor length, when L
is shorter than L e , for two different cooling efficiencies.

voltage taps cannot be facilitated in this case becauseof low levels of resistive voltage drop. For the prototype it appears that the supports and insulators laidin the coil vessel are configured to avoid a wide-range
bubble trap.

Fig. 4. Propagation of the normal conducting zone when
L is slightly longer than Le. Temperature distributions are plotted along the conductor length at different
times: tl = 20 S, t2 = 40 s, and t3 = 60 s'.

References
1) M. Wilson: Superconducting Magnets, (Oxford University Press, 1983).

217

RIKEN Accel. Prog. Rep. 33 (2000)

Analysis of the Injection and Extraction Systems for the .
RIKEN Superconducting Ring Cyclotron
S. Fujishima, H. Okuno, A. Goto, and Y. Yano
Design of the injection and extraction systems for
the RIKEN Superconducting Ring Cyclotron (SRC)
is in progress. 1) The purpose of the present analysis
is the optimization of the layouts and specificationsof the injection and extraction elements of the SRC.
In the analysis, a lot of care was taken especially tominimize not only the required fields of the elements
but also the differences between the trajectories in theelements.
The sector magnets of the SRC generate strong fieldof 4.3 T at the maximum, and also generate a strayfield in the valley originated from saturation of theiron yokes. This stray field gets up to -0.6 T at the
maximum and depends non-linearly on the magnetic
rigidities of the beams. Thus, the trajectories of various beams differ considerably from each other. Large
difference between the trajectories requires wide boreof the element. Besides, the injection and extraction elements should be installed in a small space limited withthe vacuum chambers of the sector magnets. Becauseof the space limitation and high rigidity of the beam,
the injection and extraction elements should generateconsiderably high fields. These difficulties make thedesign of the injection and extraction systems quite
challenging.

Table 1 shows the energies and magnetic rigiditiesof three typical beams. The beam of 16 0 7 + (1) has
the lowest magnetic rigidity. On the other hand, thebeam of 238U58+ has the highest one. Between these
two beams, the difference of trajectories is most remarkable. The beam of 16 0 7 + (2) requires the highest
electrostatic fields of the electrostatic channels.
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, so thecalculated fields of the sector magnets include about

Table 1. Energies and magnetic rigidities of typical beams.

16 0 7+ (1)16 0 7+ (2)238 U 58+

Energy [Me Vlu]
Inj.
Ext.

B p [Tm]
Inj .
Ext.

74.2
126.7
58.0

2.89
3.83

4.90
7.25

4.57

7.52

200
400
150

Fig. 1. Schematic layout of the elements and trajectories of two typical beams.

218

Table 2. SpeCifications of the inject'ion and extraCtion elements.
Radius[cm]

Angle[deg.]

Length[cm]

BorE (max.)[T],[kV/cm]

EIC
MIC1
MIC2
BM1
BM2
BM3
BM4
BM5
BM6

928~3217

variable
45.5
69.3
49.0
49.0
-

101.7
89.5
115.5
100.1
100.1
49.6
49.6
49.6
49.6

100
0.30 (Normal)
1.12 (Super)
4.70 (Super)
4.40 (Super)
0.25 (S uper)
1.36 (S uper)
0.90 (S uper)- 1.00 (Super)

EDC
MDC1
MDC2
MDC3
EBM1
EBM2

1578~3611

variable
37.0
39.0
36.8
17.7
39.1

212.5
119.5
129.3
130.7
52.3
104.0

-105

112.7
95.6
117.0
117.0
straight
straight
straight
straight

185.0
190.0
203.5
169.4
152.4

- 0.15 (Normal)- 0.27 (Normal)- 0.51 (Normal)- 4.00 (Super)- 4.54 (Super)

0.3% error. Error of the field causes position error
to the injection and extraction trajectories. To correct relative position error of the trajectories, the energies of the injection or extraction beams were slightly
changed as the length of the first or the last equilibrium
orbits become equal to the design value, respectively.
And then, to trace the beam trajectories, the equationof 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 16 0 7 + (1) and 238U58+. Thislayout has not been optimized completely, so it may
be modified partly. Because of the stray field in thevalley, two trajectories differ considerably from eachother. The injection system consists of six bending
magnets (BM1-BM6), two magnetic inflection channels (MIC1 and MIC2), and an electrostatic inflection
channel (EIC). The extraction system consists of two

Table 3. Differences of the trajectories and bores in ·theelements.
Difference[mm]Bore [mm]verti. X horiz.

61

MIC2~BM2=;: 13BM3 ~ BM6~70

12 (horiz.)
30X35
30X40
30X 100

EDC (movable)

75
=;:13

12 (horiz.)
30X40

EIC (movable)
MIC1

MDC1~EBM2

5

bending magnets (EBM1 and EBM2), three magnetic
deflection channels (MDC1, MDC2 and MDC3), andan electrostatic deflection channel (EDC). All MICs
and all MDCs are installed between upper and lower
coils of the sector magnets. The injection beams are
introduced crossing the EIC, so that the EIC has ahole to pass the beams. To minimize the hole diameter,each trajectory was adjusted to cross at the same pointon the electrode of the EIC.
Table 2 shows the specifications of the injection andextraction elements. The MIC1 and all MDCs consist .
of normal-conducting coils. The MIC2, all BMs andall EBMs consist of superconducting coils. The BM1
and BM2 have identical structure and size to reduce
fabrication costs. For the same reason, the BM3, BM4,
BMS and BM6 are identical. Each magnetic element
consists of main dipole coils and compensation coils tosuppress the fringe field on the first or the last equilibrium orbits. Gradient-field-coils are additionally built
in the MIC2, BM1 and BM2 to adjust the injection
beam envelopes. The length of each element was determined in consideration of the balance between the
difference of the trajectories in the element and therequired field of the element. Table 3 shows the differences of the trajectories and bores in the elements.
References
1) S. Fujishima et al.: Proc. 12th Symp. on Accelerator
Science and Technology, Wako, p. 435 (1999).

219

RIKEN Accel. Prog. Rep. 33 (2000)

Superconducting Magnetic Channel for the RIKEN Supercond~cting
Ring Cyclotron
H. Okuno , S. Fujishima, T. Tominaka, J.-W. Kim, J. Ohnishi, T. Kawaguchi, M. Okamura,
A. Goto, and Y. Yano
A six-sectored superconducting ring cyclotron(SRC) is designed to boost the energy of the ion
beams available from the Intermediate Ring Cyclotron(IRC).l) The extraction energies of the SRC beams
will be 400 Me V jnucleon for light ions such as carbon
and 150 Me V j nucleon for heavy ions such as uranium
with an intensity of 1 pJ.1.A. Figure 1 shows the trajectories of injected and extracted beams in the SRC
consisting of six sector magnets 2 ) and four acceleration
resonators. 3 ) Among the elements of the injection andextraction systems, the MIC2, BMl-2, EBMI-2 are difficult to design and further research and development
are required, because their coils are curved very tightly
and the required fields in the coils are as high as 6 T
and because the spaces for the installation are limited.
In this report , the plan and status of R&D for the
MIC2 is described.
The main parameters of the MIC2 are listed in Table 1. It needs to generate a magnetic field of about 1 T
on the base field of 4 T of the sector magnet , along thebeam trajectory, which is curved with a curvature ofabout 1 m. Figure 2 shows the proposed cross section
and 3D-view of the coil structure. Six current sheets(center coils and half of side coils) located close to theTable 1. Main specifications of the MIC2.

Item
Type

Coil configuration
Required field
Required gradient field
Maximum field in the coil
Homogeneity
Beam bore
RadiusValue
Iron free, Active shield type
Center coil, Side coil
-1.12 T

About2T/m
6.12T
J
1 x lU
240 (H) x 30 (V) mm
955mm

Angle

73 degree

Fringe field at the 1tt. E.O.

< 100 gauss
3D View

Cross Section

Center coil x
Side coil x

Shield the field

®
,;;.~

CUrrent Direction (from us to paper)
CUrrent Direction (from paper to us)
Beam Bore-..

Ruxli'le@Fig. 2. Coil structure of the MIC2.

Fig. 1. A schematic layout of injection and extraction elements for the SRC along with trajectories of the injected and extracted beams.

220

beam axis generate a magnetic field in the beam bore,
and the other two current sheets (half of side coils)
generate a field that cancels the fringe field from thesix current sheets. Such configurations of the current
sheets can realise the structure of coils that need not
be bent up at the ends of the channel, which makes
coil winding and coil supporting easier. The overall
current density is required to be about 150 Ajmm 2 toachieve the required field for the MIC2. Rectangularmonolithic (0.8 mm x 2.4 mm) wire was adopted forwell-aligned winding. The conductor was coated withpolyimide of 50 J.1.m in thickness for electrical insulation. Polyimide was adopted because of its strength
against radiation.
Coil winding is one of the key problems for the MIC2
production because the coils of the MIC2 have negative
curvature, which cannot be wound with any tension.
The winding method shown in Fig. 3 was adopted. In

Fit to negative curvature

One-layer winding

Fig . 3. Concept of the winding.
Cross sectionjGradient Coilx4

I
He Vessel
CenterGoil x 2
Set Screw

Bias Coil-

Nut

--\

Side Coilx2

Fig. 5. A coil configuration for the test center coil.

Table 2. Preliminary results of the test of the first test
coil for the MIC2. The operational condition is also
indicated in the last column.
Vertical Bolt 1

Vertical Bolt 2

No.

Fig. 4. Coil support of the MIC2.

the first step, the coil is wound into a shape with tension , which has no negative curvature. The circumference of the coil should be the same as that of the final
shape of the MI C2 coil. After winding of one layer , thelayer is pushed to the mandrel to form the proper shapeof the coil. The merit of the method is that the timerequired for winding can be shortened without a decrease in performance. The coils are mainly supported
in the horizontal and vertical directions with a pair ofcontinuous clamps and bolts, respectively. The prestress required to maintain the coil compression whenthe magnet is excited is provided by set-screw bolts , a
nut at the end of the set-screw bolt and vertical bolts
as shown in Fig. 4. The support structure was adopted
since so many zigs are not necessary to press the coils.
Ti will be used for the inner mandrel of the center coil
to decrease the degradation of the stress of the coil.
Two coils which simulate the center coils of the
MI C2 were produced and are being tested. Theircoil size, winding method/winding structure, support

Bias Field
(f)
1
0
2
2
4
3
4
4
5
0
Operation 4

Current Field in
Coil(f)
(A)
2.7
500
4.5
500
460
6.2
6.7
550
800
4.2
340
6.5

the joverall(Nmm2)
222
222
204
244
356
150

Comment
No Quench
No Quench
OuenchNo Ouench
No Quench

structure were designed to be as close as possible tothose of the real one. The coils are tested in the field
generated with a bias split coil in order to simulate thereal operation as shown in Fig. 5. Table 2 shows a briefpreliminary result for the first coil which was alreadytested. The result is promising because the quench
current is fairly larger than the operational current.
Fabrication and tests of the other coil are in progress.
References
1) T. Mitsumoto et al.: RIKEN Accel. Prog. Rep. 33, 208(2000).
2) T. Kawaguchi et al.: RIKEN Accel. Prog. Rep. 33, 214(2000) .
3) N. Sakamoto et al.: RIKEN Accel. Prog. Rep. 33, 224(2000) .

221

RIKEN Accel. Prog. Rep. 33 (2000)

Helium Cooling System of RIKEN Superconducting Ring Cyclotron
K. Ikegami, T. Kawaguchi, H. Okuno, M. Ohtake, A. Goto, and Y. Yano
A superconducting ring cyclotron (SRC) is to bebuilt in the RIKEN RI-Beam Factory Project as oneof the post accelerators of the existing KS40 ring
cyclotron. I) The SRC is designed to have a K-value of
2S00 MeV, and consist of six superconducting sector
magnets. The cold part of each sector magnet consistsof superconducting main coils, cold poles and superconducting trim coils, which are installed in a single
cryostat. The superconducting active shield coils of
a Helmholtz coil type will be installed outside of the
SRC to decrease leakage of magnetic fields producedby the SRC. 2 ) Figure 1 shows a plane view of the SRC
and active shield coils, together with the injection andextraction systems.
The injection system of the SRC consists of fivebending magnets (BMl , BM2, BM3, BM4, and BMS),
two magnetic inflection channels (MICI and MIC2)
and an electrostatic inflection channel (EIC). The
extraction system consists of two bending magnets(EBMI and EBM2), three magnetic deflection channels (MDCl, MDC2 and MDC3) and an electrostatic
deflection channel (EDC). 3) Five magnets in the injection system (MIC2, BMl, BM2, BM3, BM4, and BMS)
and two magnets in the extraction system (EBMI and
EBM2) are superconducting.
Figure 2 shows a cooling system for the SRC andactive shield coils. The cooling system will be a closedcircuit system without liquid nitrogen. It consists ofa refrigerator, the cryostat of the SRC and the active
shield coils, three compressors and five buffer tanks.
The refrigerator has a capacity of 8S0 W for thecooling of cold mass at 4.S K, and SOOO W for thecooling of thermal shields at 70 K. The cooling capacity

Fig. 1. A plane view of the SRC and active shield coils.

Rifrigerator
Buffer Tanks

Compressor

Recovery Line
4.5 K

Fig. 2. The cooling system for the SRC with an active shield.

222

for current leads is 70 llh. ,The'coil vessels which accommodate the main and trim coils are mechanicallydesigned assuming a maximum pressure of 0.5 MPa.
The cold mass weight of the six sector magnets is
360 tons. It will take 45 days to cool them from room
temperature to 4.5 K. Three compressors will be operated in this case. After the cooling is finished, oneof the three compressors will be stopped and maintained as a standby. Each buffer tank has a volumeof 100 m 3 and is connected through air valves to thecompressors and the recovery tube line, as shown in
Fig. 2. A recovery tube line will be used to introduce
evaporated helium gas into the buffer tanks if an electric power failure suddenly happens. The active shieldcoils will be cooled down to 4.5 K by the forced coolingmethod , in which supercritical helium with a pressureof 1.2 MPa is used.
Refrigerator

Buffer Tanks

Helium Compre ~sor

Recovery Li ne

Table 1. Cooling capacities ·of refrigerators for the sector
magnets and active shield coils, and the injection andextraction systems.
Capacity

Sector magnets andactive shield coils

Injection andextraction systems

Coils at 4.5 K( W)

850

160

Thermal shield at 70 K(W)

5000

1000

70

12

Current lead ( Q!h )The coil vessels of superconducting magnets in theinjection and extraction systems will be designed assuming a maximum pressure of 0.3 MPa. Because themaximum pressure and the cooled volume of the magnets are small compared with those of the SRe , another cooling system will be used for the injection andextraction systems. Figure 3 shows the cooling system
for the injection and extraction systems. The coolingsystem consists of a refrigerator, the cryostat of themagnets, a compressor and two buffer tanks. The refrigerator has a capacity of 160 W for cooling at 4.5 K,
and 1000 W for the cooling of thermal shields at 70 K.
The cooling capacity for current leads is 12 llh. Eachbuffer tank has a volume of 50 m 3 and is connected
through air valves to the compressor and the recovery
tube line. The cooling capacities of the refrigerator
for the sector magnets and active shield coils, and theinjection and extraction systems are listed in Table 1.
References

70K

Safty ValveandInjection
Extraction
Systems

J~~~~~~_ _4.5 K

Fig. 3. The cooling system for the injection and extraction
systems.

1) A. Goto et al.: RIKEN Accel. Prog. Rep . 32, 193 (1999).
2) J. Ohnishi et al.: RIKEN Accel. Prog. Rep. 32, 205(1999).
3) H. Okuno et al.: Proc. 12th Symp. on Accelerator Science and Technology, Wako , p. 334 (1999).

223

RIKEN Accel. Prog. Rep. 33 (2000)

Design of the RIKEN-SRC* RF System
N. Sakamoto, O. Kamigaito, A. Goto, Y. Miyazawa, T. Chiba, H. Okuno, T. Mitsumoto, and Y. Yano
For the RIKEN RI-Beam Factory (RIBF)l) the newbooster ring cyclotrons, the Intermediate-Stage Ring
Cyclotron (IRC) and the superconducting Ring Cyclotron (SRC), are planned to be constructed to boost
the energy of heavy-ion beams from the RIKEN Ring
Cyclotron (RRC) to the intermediate energy region of
60-400 MeV lu with a beam intensity of 1 pJ-LA.
The SRC 2 ) requires acceleration resonators 3) with awide frequency range from 18 to 38.2 MHz to suit thecondition of the RRC operation.
The maximum magnetic field of the SRC sector magnet is as large as 4.2 T. Because of the strong magnetic
field, a high acceleration voltage is also required in order to obtain a large turn separation. A large turnseparation at the extraction orbit is crucial to reducethe beam losses at the extraction devices. For example, in the case of 16 0 7 + ion acceleration up to the
maximum energy of 400 MeV lu at the rf frequency of
38.2 MHz with a harmonic number h = 6, an acceleration voltage of 2.4 MV Iturn is required to obtaina turn separation larger than 4 mm at the extraction
orbit.
A flat-top system is also helpful in reducing thebeam losses at the extraction because the energy
spread of the accelerated beam can be reduced by flattop acceleration. The phase acceptance /:l¢, which isdefined by IV(/:l¢)IIV(¢ = 0) :::; 10- 4, for non-flat-top
acceleration and flat-top acceleration are ±0.81° and±7.3°, respectively.
In order to realize a large turn separation, four acceleration resonators are employed. The peak voltageof the resonators is set to be 600 kV pi gap at the highest frequency operation. One flat-top resonator withthe third-harmonic of the acceleration resonator is employed and its peak voltage is set to be about 11% of
the acceleration voltage.
The key parameters of the present design of the resonators are listed in Table 1. Since the location of theflat-top resonator has been moved from the center region of the valley chamber to next to the acceleration
resonator (see Fig. 1), a new design of the fiat-top resonator has been introduced. The dimensions of theaccelerator resonator have also been rearranged.
For the flat-top system the third-, fourth-, and fifthharmonics are used. This is helpful for the mechanicaldesign of the flat-top resonator because the frequency
range becomes narrower. The frequency range of the
new flat-top resonator is 85.97-114.6 MHz instead of
54.0-114.6 MHz which is for the third-harmonic system. The phase acceptances of the fourth- and thefifth- harmonic flat-top system (Fig. 2) are sufficiently
Superconducting Ring Cyclotron

224

Table 1. Key parameters of the acceleration and the flattop resonator for the SRC.
resonators
No. of units
Frequency [MHz]Ace. gap[mm]
Aperture[mm x mm]Coarse tuner
Tuner stroke
Trimmer
FeederMax.V p [MV /gapj
Voltage stability
Phase stability
Max. power [kW]Q-values

flat-top
acce!.
1
4
18-38.2
85.97-114.6
single gap
120
250
60 H
60 H
x 2240 w
x 1975 w
shorting plate
flapping panel
0-90°
500-1100 mm
block tuner
inductive loop
0.6
0.36
10- 4
10- 3
±0.1 °
±0.3°
81
43
37000
25000

Fig. 1. Top view of acceleration resonator No.4 and flattop resonator.

"'.:"-- 1.0004
I......

S-:s:

1.0002~~ l .oooof- ··· ·· ·:· .. f / , .. ,.. ·,· .. ·

(J

00.:
i;; 0.9996
(:S

I

~
V; 0 .9996
o

(J

- 10

a
¢ (deg.)10

Fig. 2. Acceleration voltage with a flat-top resonator. !:J.¢
IV(!:J.¢)I/V(¢ = 0) ::; 10- 4=

large to accept the beam from the RRC.
The acceleration resonator is a single-gap type whose
structure is basically the same as that of the RCNP
ring cyclotron (RCNP-RC).4) The resonant frequency

is tuned by adjusting two flapping panels which areplaced symmetrically to the median plane.
The rf characteristics of the acceleration resonatorare calculated at the flapping panel positions of 0° and
90° by MAFIA,5) as shown in Table 2. Since the Qvalue and the shunt-impedance of the actual resonatorare expected to be 60-70% of the theoretical values ,6)
the maximum rf power dissipation of the actual resonator is estimated to be 115- 135 kW. The calculated
current density at the sliding contacts (see Fig. 3) isless than 60 A/cm.
The new design of the flat-top resonator for the
SRC is shown in Fig. 2. Resonant frequency tuningis achieved by moving the shorting plates which areplaced symmetrically with the median plane. By utilizing the multi-harmonic numbers of 3, 4, and 5, therequired frequency range becomes 85.97-114.6 MHz.
As shown in Fig. 4, the frequency range is successfully covered by moving the shorting plate from 500 to
100 mm with large Q-values (Fig. 5) . The maximum
wall loss is estimated to be 85 kW if the Q-value of theactual resonator is 50% of the theoretical value.
The main parameters of the rf amplifiers are listed
in Table 3. The design of the final stage amplifier
for the acceleration resonator is the same as that of
the RRC. Since the transmitter tubes do not functionin the strong magnetic field, the amplifiers are to beplaced where the leakage field of the SRC sector magnets becomes smaller than 50 Gauss. The length ofthe power transmission lines is estimated to be 50 m.
Table 2. The calculated rf characteristics of the acceleration resonator obtained by MAFIA.
Flapping Panel
Frequency [MHz]Q-valueRs [MnJ
Vp [kV]
pw.l. [kW]o deg.
17.474
28200
0.63
250
50

90 deg .
38.607
36649
2.23
600
81

I

t

2025

...

~
~Nr~T
---~~

Fig. 4. Schematic view of flat-top resonator.

140
Ul

Q

~

C!

g.

III

I

20000 '< "0':r:j<ll

III§JlJ _M.H_z__ ________ ~_____ _

~

cr
Q)

P'
.o~

~§'

~ ~[ X 1/ 50)g>.. 100
Q)

25000

I')

fr equency

80

PPl

b ~
.., CD
15000

2

60
250

500

10000
1500

750

Position of the Shorting Plate [mJ

Fig. 5. Calculated rf characteristics of the flat-top resonator obtained by MAFIA.
Table 3. Characteristics of the RF amplifier.
Frequency
Wide band amp.
2nd stage
Output power
Final stage
Output power
Trans. line

[MHz]
[kW]
[kW]
[kW]

flat-top
acceleration
85 .97-114.6
18.0-38 .2
1
1
RS2012CJ
15
5RS2042SK
RS2058CJ
300
100
WX152D/50n

References

Fig. 3. Schematic view of acceleration resonator. Resonances with the lowest and highest resonant frequencies
are obtained when the flapping panel is horizontal (0°)
and vertical (90°) , respectively.

1) Y. Yano et al.: Proc. 1997 Particle Accelerator Conf.,
Vancouver, 1997, p. 930 (1998).
2) A. Goto et al.: Proc. 12th Symp. on Accelerator Scienceand Technology, Wako, 1999, p. 7 (1999).
3) N. Sakamoto et al.: Proc. 15th Int. Conf on Cyclotrons
and Their Applications, Caen, 1998, p . 223 (1999).
4) T. Saito et al.: Proc . 12th Int. Conf. on Cyclotrons andTheir Applications, Berlin, 1989, p. 201 (1990).
5) The MAFIA Collaboration, User's Guide MAFIA Version 4.0, CST GmbH, LauteschagerstraBe 38, D-64289,
Darmstadt, Germany.
6) N. Sakamoto et al.: Proc. 12th Symp. on Accelerator
Science and Technology, Wako, 1999, p. 224 (1999) .

225

RIKEN Accel. Prog. Rep. 33 (2000)

Vacuum System for the RIKEN Superconducting Ring Cyclotron
K. Sugii, K. Ikegami, S. Yokouchi, A. Goto, and Y. Yano
Beam transmissions are aimed to be above 99% for
all ion beams available in the RIKEN Superconducting
Ring Cyclotron (SRC). We have estimated the requiredpressure of the beam chamber on the basis of the relationships between pressure and beam loss which is
caused by a change in the charge state of the beam
due to collisions with residual gas. As an example,
Fig. 1 shows the beam transmission of 238U58+ ionsas a function of pressure of the beam chamber, since
the charge-exchange cross section of heavy ions suchas 238U58+ is very large. As can be seen from Fig. 1,
the required pressure should be below 1 x 10- 5 Pa in
order to achieve the goal of 99% beam transmission.
The vacuum chamber of the SRC consists of six
beam chambers each in the sector magnet , four RF resonators, a flattop resonator, two valley chambers , andbeam pipes for injection and extraction (see Fig. 2).
Table 1 gives the total volume of the vacuum chamber
and the surface areas of the main materials in the vacuum chamber. We plan to use 18 cryopumps with a
total pumping speed of 170 m 3 Is as the main pumping system in order to achieve the required range ofpressure as quickly as possible.
Figure 3 shows the design of the pumping system forthe vacuum chamber of the SRC. The pumping system
consists of a roughing system, a high-vacuum system,
an ultrahigh-vacuum system and a differential pumping system. The surface areas of the RF resonatorsand the flattop resonator are very large, since the resonators have a duplicated wall structure same as the.~ ....... . .

··· ·· · _· ..·.. _··- ::·: :·:· : ::: · :·: : : : : ·h

. .. ............. ... ...... .... - .

:·: :....

0.8.\ ...

0.6....... . ..... .......................... . : .... ....... . ...

§ -- ---- -=:=~: - -:~j,.. . . . . . . . . . . . . . . . . . . . . . . . .
.
.
·
·
.
·
·. . r·g 0.4 U

-i

[/)

I-

~
Q.)

CO 0.2 I-

238

58+

T inj . = 58.0 MeV/nucleon

Text. = 150 MeV/nucleon(J= 4 X10- 18 cm2T

t = 5.8 X 10-

10-5

5

sec
10-4

10- 3

10-2

Pressure (Pa)Fig. 1. Beam transmission of 238U58+ ions at the injectionenergy of 58.0 MeV/nucleon as a function of pressureof the beam chamber.

226

Fig. 2. Plan view of the SRC.

Table 1. Total volume of the vacuum chamber and thesurface areas of main materials exposed to ultrahighvacuum. The values including the extent of subvacuum
are shown in parentheses.

Area Stainless steel
CopperFPM (O-ring)
Volume197 (442) m:l
356 (605) m:l
3.4 (5) m:l85 (90) m;)

IRC resonators; copper plates with a thickness of approximately 4 mm are located on 25 mm away fromthe stainless steel vacuum walls.!) We plan to evacuate
the gas in the subvacuum space between the vacuum
walls and the copper plates by a differential pumping
system in order to reduce the gas load for the cryopumps. Therefore, it is necessary to minimize theleak rate from the subvacuum space to the ultrahighvacuum space. The roughing system is composed ofa roots pump of 2600 m 3 /h and a rotary pump of
290 m 3 /h, and is installed at each valley chamber. The
high-vacuum system is composed of a turbomolecularpump of 5.5 m 3 Is and a rotary pump of 155 m3/h. This
high-vacuum system is installed at each RF resonator.
The high-throughput-type turbomolecular pump will
be used for the following reasons: (1) to shorten thepumping time prior to the ultrahigh-vacuum systemby switching from the roughing system to the highvacuum system at a high pressure (about 70 Pa), and(2) to prevent the contamination in the RF resonator8eamline for in'ection

Roughing system

CP1: cryopump of 10 m3/s. CP2: cryopump of 5 m3/s
TMP 1: turbomo 1ecu lar pump 0 f 5,5 m3/s. TMP2: turbomo 1ecu 1ar pumpRP1~3: rotary pump.
MBP: roots pump
SV. SV2: safety valve~

cold cathode gauge@ pirani gauge~

Q9 hot cathode gauge [B-Al~

mass spectrometerpressure switch

Differential pumping systemFig, 3. Pumping system for the vacuum chamber of the SRC.

caused by the backflow of oil vapor from a rotary pumpby the same switch. If the ultrahigh-vacuum systemwith cryopumps starts to operate at a pressure of 1 x
10- 3 Pa, the total pumping time required to reduce theatmospheric pressure to 1 x 10- 3 Pa using the roughing pump and the turbomolecular pump is calculated
to be approximately 22 hrs. The ultrahigh-vacuum
system deploys 18 cryopumps: 16 of which are 10 m 3 /sand two of which are 5 m 3 /s. The 5 m 3 /s cryopumps
are installed at the flattop resonator and the 10 m 3 /s
cryopumps are distributed to the two valley chambers
and each of the RF resonators. We chose cryopumps
as the main pump for the ultrahigh-vacuum system,
because they have high pumping speeds against thewater vapor and hydrogen gas, both of which are thepredominant residual gas components in an unbaked
vacuum system. Furthermore, they can be operated
even under a large environmental magnetic field. The
total effective pumping speed of the cryopumps is approximately 75 m 3 /s. Considering this pumping speed
and the published data for the outgassing rate of materials, the pumping-down time to achieve the order of
10- 6 Pa is estimated to be a few hundred hrs.

The pressure in the vacuum chamber of the SRC will
be measured with a nude-type hot ionization gauge
during a nonoperation period of the SRC. During the
SRC operation, a cold cathode gauge will be used, since
a hot ionization gauge is impractical use due to a large
leakage flux from the sector magnet . A cold cathodegauge is equipped with a permanent magnet, therefore, it is expected to be usable even in an external
magnetic field. Measurement of pressure using a cold
cathode gauge under an external magnetic field wasreported.2 ) However, we also measured the influenceof an external magnetic field on cold cathode gauges,
because the pressure measurement is limited by a large
leakage flux from the SRC magnet. 3 )References
1) T . Hiasa et al.: Proc. 12th Symp. on Accelelator Scienceand Technology, RIKEN, p. 293 (1999).
2) N. Yasumitsu: Proc. 8th Meet. on Ultra High Vacuum
Techniques for Accelerators and Storage Rings, KEK ,p . 75 (1992).
3) K. Sugii et at.: RIKEN Accel. Prog. Rep. 33,228 (2000).

227

RIKEN Accel. Prog. Rep. 33 (2000)

Influence of External Magnetic Field on the Performance ofCold Cathode Gauges
K. Sugii, K. Ikegami, M. Otake, S. Yokouchi, A. Goto, and Y. Yano
A Cold Cathode Gauge (CCG) is used to monitor
the pressure of a vacuum chamber during the operationof the Superconducting Ring Cyclotron (SRC) sector
magnet. To examine the effect of external magnetic
fields on the performance of CCGs, an experiment using an electromagnet was carried out. Since the pressure required for the beam chamber of the SRC is estimated to be of the order of 10- 6 Pa,l) the vacuum
gauge used in the SRC beam chamber is required ,tohave a minimum measuring range which is one orderor more lower than the order of the required pressure.
Therefore, we chose two types of CCGs available on themarket, that is, (1) Balzers: IKR060 and (2) Leybold:
PR36.
A schematic diagram of the experimental setup is
shown in Fig. 1. Figure 2 shows a photograph of the
CCG set in a magnet gap. Both CCGs were positioned
in such a way that the direction of the magnetic fields
generated by the permanent magnets coincided withthose of the external magnetic fields. For testing inan external magnetic field with a gradient, the eeGs
were placed around the pole edge. The gradient of
the external magnetic field at that position was estimated to be about -0.74 Tim at a uniform field of 1 T.
The measurement was performed under the following
four conditions: (1) without a permanent magnet in a
uniform external magnetic field, (2) without a permanent magnet in a nonuniform external field, (3) witha permanent magnet in a uniform external field, and(4) with a permanent magnet in a nonuniform external field. For the measurement without a permanent
magnet, the pressure at zero field was measured using
a permanent magnet.

Fig. 2. eeGs in the pole gap.
Figure 3 shows the changes in pressure as a functionof the external magnetic field near IKR060 without apermanent magnet when the external field is uniform.
The pressure increases as the external field increases
in the case of a low initial pressure. Figure 4 shows
the changes in pressure without a permanent magnet
of both CCGs when the external field is not uniform.
In the case of IKR060, the trend of change at pressures
above 3 x 10- 5 Pa is similar to that in the case of a uni-

--

a

~

ro 10- 4

~

.....

~

'-"

....

~

::J
CI)
CI)

Cl.>

ct 10- 5~

IL-- with a permanent magnet ( ....... 0.1 T)

lMP (300 LIs)
Pirani
The dircction of the magnctic fieldsof the CCGs and electromagnet

Fig. 1. Schematic diagram of the experimental setup.

228

-----

-.

~

I

I

I

I

0.2

0.4

0.6

0.8

External magnetic field (T)CCG : IKROGO (Balzers)

Fig. 3. Changes in pressure as a function of the magnetic
field near IKR060 without a permanent magnet whenthe external field is uniform.

... -.. ..

...

......

-.... ~.,/',~~ with a permanent magnet (-0.' T)~-------1'--/1-.

~~! - - - with a permanent magnet (-0.'4 T)

\

7

0.2

0.4

0.6

External magnetic field (T)

(a)

0.2

0.8

CCG : IKR060

0.4

\

0.6

0.8

External magnetic field (T)(b)

CCG : PR36

Fig. 4. Changes in pressure as a function of the magnetic field near CCGs without a permanent magnet
when the external field is not uniform: (a) IKR060 and (b) PR36.

:..---+- ......

-

r--

.....

.........

N

~

....-

~

-+

~

----

~
~ f-----'~.... --.

--

V

.1

....

~

f---.
~

....

.

7

0.5

1
1.5
Magnetic field (T)

2

0.5

1
1.5
Magnetic field (T)2

CCG : IKR060

CCG : IKR060

Fig. 5. Changes in pressure as a function of the magnetic
field near IKR060 with a permanent magnet when theexternal field is uniform.

Fig. 6. Changes in pressure as a function of the magnetic
field near IKR060 with a permanent magnet when theexternal field is not uniform.

form magnetic field. In the case of PR36 , the change
in pressure is larger than that for IKR060. The causeof this instability is thought to be due to the fact thatthe axis of PR36 was not exactly parallel to the lines ofthe external field; PR36 was located slightly away fromthe median plane of the magnet (see Fig. 2). Figures 5
and 6 show the changes in pressure as a function of themagnetic field near IKR060 with a permanent magnet.
The .results in the case of a uniform field are shown in
Fig. 5. It can be seen from this figure that the pressure de<tre~ses ~uddenly in the range of 0- 0.25 T anderrors in measurement are observed when the pressure
at zer~ . fi~ld was above lO-5, ,Pa. The results in thecase ,of a ,nonuniform field are .shown in Fig. 6. It canbe o.bserved ,that the pattern of change in pressure issimilar totpat seen in Fig. 5., 'We conclude that we can use CCQs to monitor thepressure of a vacuum chamber in leakage flux of the
SRC sector magnet unless we wish to pursue a more
precise measurement. It is recommended to use a
CCQ without a permanent magnet because the external magnetic field during SRC operation is expected tobe below 0.3 T, in which range measurement using a
CCQ with a permanent magnet becomes erroneous forunknown reasons . Moreover, we must determine thecause of errors in measurements using a CCQ withouta permanent magnet when the external field is verysmall (0-0.1 T).
References
1) K. Sugii et al.:(2000) .

RIKEN Accel. Prog. Rep. 33, 226

229

RIKEN Accel. Prog. Rep. 33 (2000)

Design Studies on Beam Transport System of
RIKEN RI Beam FactoryN. Fukunishi, K. Kusaka, H. Sakurai, T. Kubo, T. Nagafuchi, H. Okuno, T. Mitsumoto,S. Fujishima, M. Kase, A. Goto, and Y. Yano
The beam transport system in the RI Beam
Factoryl) (RIBF) consists of four parts; one is a beamline from the RRC to the IRC. The maximum magnetic
rigidity (Bp) required for the beam line is 2.94 Tm
which corresponds to a 24.5-MeV /nucleon 238U58+
beam. The second is a beam line from the IRC to the
SRC. The maximum Bp is 4.57 Tm corresponding to a58.0-Me V /nucleon 238U58+ beam. The third is beamlines from the SRC to experimental halls through the
Big-RIPS. The last one is a beam line that returns
the beams accelerated by the IRC to the RARF. In
this report, we will explain the present status of design studies on the beam line from the RRC to the
IRC and that from the IRC to the SRC. The layout of
the beam lines is illustrated in Fig. l.
The beam line from the RRC to the IRC mainly consists of five bending magnets, eight quadrupole triplets ,two quadrupole doublets and seven quadruple singlets.
In addition , there is another Q-doublet in the injection
system of the IRC (QDI3) . The functions required forthe beam line are the dispersion matching, the matching of phase-space ellipses in the transverse direction(beam shaping) and the RF-phase matching.
For the dispersion matching, the bending magnet(BMl) in the injection system of the IRC is designed
to produce the desired dispersion. The actual condition required for the beam line is to make a doubly
achromatic beam immediately before the BMI. The

Fig.!. Layout of the beam transport system of the RIBF.

230

spatial dispersion of the RRC beam is roughly 2.5 m
at the Electric Deflection Channel (EDC). The angulardispersion is zero at the EDC. The 90-degrees bending magnet (BM90) in the El experimental hall makes
a doubly achromatic beam (see Fig. 2). In addition,
the section from the EDC to the QTE13 is an entirely
doubly telescopic system. This enables us to perform
an emittance measurement for a beam at the PI pointin the beam line. The momentum analysis will be also
performed with the bending magnet BM90.
The beam shaping is carried out using four Qsinglets (QSI2-QSI5). To this end, the beam line isdesigned to have horizontal waists at the QSI2 and the
QSI4, and to have vertical waists at the QSI3 and the
QSI5. The section from the BM24-1 to the BM24-2 isdoubly achromatic and matches the beam direction to
the injection system of the IRC. The section from the
BM30-I to the BM30-2 is also doubly achromatic andlowers the beam line by 3 m. This vertically achromatic feature causes a beam to be defocused in thehorizontal direction. To avoid the divergence of thebeam, the Q-doublet QDI2 focuses the beam before
this section.
We show the results of an ion-optical calculationin Fig. 2. The calculation was performed using the
TRANSPORT code. 2) The emittance of the beam is
57r mm mrad and the momentum spread is ±0.05%
in the present calculation. The assumed value of theemittance is based on the observation but depends on
the actual beam tuning. For the momentum spread,here we use double the observed half-width. The maximum value of the quadrupole-filling factor is designed
to be 50%.
With respect to the beam bunching, detailed investigations are necessary. The RF-phase width of the
RRC is 10 degrees. On the contrary, the RF-phase acceptance of the IRC is 20 degrees because a flattop resonator is introduced. The first-order ion-optical calculation with ±O.05% of the momentum spread predicts
that the full width of the beam pulse at the Electric Inflection Channel (EIC) of the IRC is 24 degrees, which
nearly corresponds to the RF-phase acceptance. Notethat the assumed value of the momentum spread isdouble the observed half-width.
The functions required for the beam line from the
IRC to the SRC are the dispersion matching and thebeam shaping. The beam bunching is not necessary because the beam transport system is sufficiently short.
The beam line consists of two bending magnets, seven
Q-singlets and a Q- doublet. In addition, the injection

OTA02

20mm

OTE12

BM90

OTE13

P14m

enve lope (vertical)
dispersion (vertical)
20mnf~1__~Q~0~11_____Q=S"I~1~~O~S~13~~O~SrI5~B~M2~4~.1~B~Mr2~4.~2~~B~M~30r·1~Q"TI~1~B~M~30r·2~m-______~OOnlr3~B~M_1.-__1~ns~id~e_IR~C--,4m

o 12

OSI4

OSI6

OSI7

0012

OTl2

Fig. 2. Beam envelopes and dispersion calculated for the beam line from the RRC to the IRC. Thick andthin lines represent the horizontal and vertical directions , respectively. The full scale is 20 mm for the
beam envelope and 4 m for the dispersion.

system of the SRC has another Q-doublet. In the beamline, there are no sections that are doubly achromatic.
Hence, the beam shaping and the dispersion matching
couples mutually. The roles of the Q-magnets are as
follows. The QSSI changes the beam shape for bothhorizontal and vertical directions but has little effecton the dispersion. The QSS2 is very sensitive to thebeam shaping in the horizontal direction. On the contrary, the QSS3 mainly changes the beam shape in thevertical direction. The QSS4 and the QSS6 are mainly
used for the dispersion matching. Moreover, the firstmagnet of the QSDI is important for both the beam
shaping and the dispersion matching. By adjusting
the six Q-magnets as mentioned above, the beam accelerated by the IRC is matched to the conditions ininjecting to the SRC.
We show the result of an ion-optical calculation in
Fig. 3. In this calculation, the matching conditions are
given at the entrance of the BM2 magnet of the injection system of the SRC. From the BM2 to the EIC of
the SRC , orbit calculations were performed. The assumed emittance of the beam is 3.37r mm mrad and theassumed momentum spread is ±0.05% in this calculation. The quadrupole-filling factor is less than 50% forthis beam line. The dispsersion (horizontal) calculated
here is also shown in Fig. 3. It should be noted here

EBM2

ass,

Fig. 3. Beam envelopes and dispersion for the beam linefrom the IRC to the SRC.

that the matching conditions in the present calculation
are given only for a 238U58+ beam that corresponds tothe highest magnetic rigidity. In the area near the
SRC, there exists the strong stray field from the sector magnets of the SRC that depends nonlinearly on
the magnetic rigidity of the beam. 3 ) In this sense, weneed to study beams with low magnetic rigidity, eventhough the present design of the beam transport system is designed to match various conditions.
References
1) Y. Yano et al.: Proc. 1997 Partlicle Accelerator Conference, 1, 930 (1997).
2) K. L. Brown et al.: SLAC91, Rev. 1 (1991).
3) S. Fujishima et al.: Proc . 15th Int. Conf. on Cyclotrons
and Their Applications 1998, p. 485 (1998).

231

RIKEN Accel. Prog. Rep. 33 (2000)

Design Study of Beam Transport Lines from SRC toThree Big RIPSs
K. Kusaka and T. Kubo
In the RI-Beam Factory (RIBF) project,l) energetic
heavy-ion beams from the RIKEN superconducting
ring cyclotron (SRC) will be delivered to projectile
fragment separators, called Big RIPS,2) to produce RI
beams. Constructions of three Big RIPSs are being
planned. Two of them, called Big RIPS I and II, arededicated to ordinary RI-beam experiments. The third
Big RIPS will be for the Multi-USe Experimental Storage rings (MUSES), in which produced RI-beams are
injected into the accumulator cooler ring (ACR). These
three separators share the primary beams from SRC bymeans of time sharing. A design study of beam transport lines from SRC to Big RIPS's has been carriedout , taking constraints of building layout and designof magnets into account.
In this design study, we consider the following timesharing system. Since ACR can accept short-pulsed
beams with a small duty factor, we consider a kicker
magnet (KM) to deliver primary beams to MUSES
lines. A strong KM , which bends SRC beams by 7° atan orbit radius of 9 m in a period of ",50 j1sec, is underconsideration. The time sharing between Big RIPS I
and II is designed to be realized by a fast pulse magnet(PM) with a ramping time of less than 50 msec. Its
bending angle is 20° and the orbit radius is 5.5 m. R
& D studies of these magnets are in progress. A highfield normal conducting bending magnet (HFBM) is
also under consideration, since bending magnets withsmall orbit radii are indispensable for fitting the beamlines in a limited area of the new RIBF building. Although a superconducting magnet is possible, we prefer
HFBM from the view point of cost and ease of operations. The maximum field of HFBM is assumed tobe 2 T. A design study of HFBM has shown that it ispossible to build such a high-field magnet with a goodfield uniformity of 10- 4 . 3)
A possible layout of beam lines together with SRC
and Big RIPS I is schematically shown in Fig. 1. Three
quadrupole doublets (QDs) transport a primary beamfrom SRC to a bending magnet (BM). The BM changes
the direction of the beam 30° making the beam achromatic together with two QDs, so that the beam focuses at the intermediate focus IF. A 60 0-HFBM, together with two quadrupole triplets (QTs), transports
the beam from IF to the KM. While the KM is excited, pulsed beams are delivered to the MUSES line.
While the KM is off, on the other hand, an unkickedbeam is transported to the pulsing magnet (PM). The
PM, when excited, steers the beam to the beam line
to the target T1 for Big RIPS 1. The beam line after
PM consists ofQD- 700-HFBM-QT-QT. When the232

PM is off, the beam is delivered to a branch line to thetarget T2 for Big RIPS II which consists of QD-200BM-QD-700-HFBM- QT- QT. The last QT pairs
focus the beam on the targets T1 and T2. Both beamlines from IF to T1 and to T2 are achromatic pointto-point focusing. For the quadrupole multiplets , wehave assumed two types of magnets. One has a 40 cm
magnetic length and the others 75 cm. Figure 2 shows
an example of calculated first order beam envelopes ofthese beam lines from the EBM2 exit to T1 and T2.
The assumed beam is 238U59+ with an energy of 150
MeV lu, emittance of t:x = t:y = 57r mm mrad , andmomentum spread of b..plp = ±0.05%. The calculated
field gradients of quadrupoles are typically 10-15 Tim
and the beam spot size on the target Tl and T2 is
1.2 mm in this case.
We have demonstrated that primary beams from
SRC can be delivered to the three Big RIPSs bytime sharing in the present floor-plan of the new
RIBF building without introducing any superconducting magnet. Further optimization of the layout andmagnet design is in progress.

Dc

10 m

Fig. 1. Schematic layout of the beam transport line from
SRC to Big RIPSs.

IF

4cm r

KM

~

~

o

"'. - ~
V

~

I>r'

---~

I---- l'- V~k ~V i'--~ .. .. -V'---.... .... ,
'---

~.

off) PM
.-

---

~

HFBM
r--

-,,-~v

ffl ---- r\ II

L

--:=

lJ 1\

~f'.

BM

4cm ' -

Big RIPS II branch

10 m

horizontal

verticalI'

HFBM

r- . .

tv

T2-------

Fig. 2. First-order beam envelope.

References
1) Y. Yano et al.: Proe. 15th Int . Conf. on Cyclotrons andTheir Applications, p. 696 (1998) .
2) T. Kubo et al.: RIKEN Aceel. Prog. Rep. 33, 236(2000).
3) T. Nagafuehi et al.: RIKEN Aecel. Prog. Rep. 33, 234(2000).

233

RIKEN Accel. Prog. Rep. 33 (2000)

Design of a 2 T Room-Temperature Dipole Magnet for BeamTransport Lines of RIBF Project
T . Nagafuchi, M. Okamura, and T. Kubo
In this report, we describe the design of a highfield room-temperature dipole magnet to be used in
the RIKEN RI-beam factory (RIBF) project. 1)
In the RIBF project, heavy ion beams extracted
from the superconducting ring cyclotron (SRC)2) areto be delivered to the target positions of BigRIPS(RIKEN projectile fragment separator)3) to produce
RI beams. The beam transport lines between SRC
and BigRIPS are being designed. 4) According to thebuilding layout for the project, the beam lines must
be bent by a total of 150 degrees to reach the target
positions . This bend is to be made using two dipole
magnets, between which a number of quadrupole magnets, a kicker magnet , and a pulsing magnet are to
be placed. The kicker and pulsing magnets are used
for the time sharing of a primary beam. 4 ) It is foundthat the limited space in the building makes it difficult to install these magnets, if the dipole magnets aredesigned to be conventinal room-temperature magnets
with the field strength of 1.5 to 1.6 T .
One solution to this problem is to build superconducting dipole magnets with high fields such as 3 T .
In this case, although the fabrication cost is high,much more space becomes available , since the magnets become much smaller. Another solution is tobuild room-temperature iron-dominated dipole magnets with high fields. An optics design of the beamlines has shown that sufficient space becomes available if the field strength chosen is 2 T. 4) The key
points to be considered in this case are: (1) sufficiently
good uniformity at such high fields , and (2) efficientwater-cooling of magnet coils. We decided to examine
the second solution, because not only can the roomtemperature magnet be designed easily, but also it canbe fabricated at a low cost , as compared with superconducting ones.
As for the type of dipole magnet , we chose the modified window-frame type as shown in Figs. 1 and 2,
because a large space can be made available for thecoils as compared with other types, hence facilitating
the cooling, and it was expected that this type might
have a good uniformity. We have developed the design by means of a two-dimensional filed calculation,
taking field uniformity into consideration. The coilcooling was also taken into account simultaneously.
The calculation was carried out using the code
OPERA-2d.
The modified window-frame-type dipole magnet has
an inner coil and an outer coil as shown in Fig. 2. It was
found in the course of designing that the field uniformity was sensitive to the coil geometry. Therefore, in

234

I'

3927.0 (60' ) • 458l. 5 (70' )I~------+-------t
I

Fig.!. Schematic diagrams of a 2 T dipole magnet.
1zoo
600

Fig. 2. Cross-sectional view of a 2 T dipole magnet.

the design we optimized the field uniformity by adjusting the horizontal and vertical dimensions of the coils,
particularly those of the outer coil. The dimension of
the hollow conductor as well as the horizontal and vertical turn numbers were adjusted in the optimization.
The geometry of pole pieces such as chamfering of theside edge was also optimized. Figure 2 shows a crosssectional view of a magnet thus optimized. Some basic
parameters of the magnet are listed in Table 1. The inner and outer coils are connected in series , but consistof different conductors whose specifications are given
in Table 1. The turn numbers per pole are 10 for the
inner coil (horizontally, 5 and vertically, 2), and 60 for
the outer coil (horizontally, 10 and vertically, 6). The
nominal operation current is 723 A for 2 T. The coilcooling is divided into eight circuits (2 for the innercoil and 6 for the outer coil). The temperature riseof the coil at 2 T is estimated to be about 14 degrees
at a cooling-water pressure of 3.5 kg/cm 2, when thebending angle is 70 degrees.

Table 1. Main parameters of a 2 Tdipole magnet.

Magnetic rigidity
Bending radius
Bending angle
Dipole field strength
Pole gap
Thrn number per pole
Thrn number of inner coil per pole
Thrn number of outer coil per pole
Hollow conductor of inner coil
Hollow conductor of outer coil
Nominal current
Good field region
Magnetic field uniformity

7.52 Tm
3.75 m60, 70 degree
2.01 T
60 mm
70
10
60
11.5 mmW x 11.5 mmH- if; 8 mm
16 mmW x 16 mmH- if; 10 mm
723 A±50 mmBetter than 2 x 10- 4

1.5E-04

2.5-ir-793 AI
2.1149 T

1.0E-04-+-422N
1.2333 T>-coEc. 2.0
~

/

4Il

>-

. .•••• good fieldregionco.........

/ V

5.0E-05-a-&-211 N
0.6171 T_ _ 633 AI

O.OE+OO

1.8011 T-e--844N
2.1816 T-5.0E-05

a

20

40

60

x [mm]-£ 1.5

....o
-a

] 1.0

//

o

.~

~

~ 0.5

/

V

/
0.0
a

L

V

---

~

100 200 300 400 500 600 700 800 900 1000 11 00
Excitation current [A]Fig. 3. Midplane field uniformity of a 2 T dipole magnet
shown as a function of horizontal position X. X = 0
denotes the center of the magnet.

Figure 3 shows field uniformity as a functionof horizontal position on the median plane of themagnet. It is shown that the field uniformity of about
1 x 10- 4 has been achieved at the horizontal positionof ±50 mm up to the field strength of 2 T. It issurprising that an iron-dominated dipole magnet can
exhibit such good uniformity at such a high field. It isinterpreted that this is because the field distribution
generated by the coils cancels well that generated by
the iron pole pieces. Note that the field distributionsof these two contributions behave in opposite ways:
one increases while the other decreases at larger
horizontal positions. It was found that suitable coildimensions had to be selected, so that the two contributions could cancel each other well. For instance,
if the turn number of the outer coil is chosen to be

Fig. 4. Excitation curve of a 2 T dipole magnet as functionof operation current.

eight both horizontally and vertically, the uniformity
becomes about 1 x 10- 3 , which is 10 times worse thanthat shown in Fig. 3.
Figure 4 shows the excitation curve as a functionof operation current. The power consumption is estimated to be about 100 kW at a 2 T in case of a bending
angle of 70 degrees.
References
1) Y. Yano et al.: Proc. 15th Int. Conf. on Cyclotrons andTheir Applications, Caen, France, 1998, p. 696 (1998).
2) A. Goto et al.: Proc. 15th Int. Conf. on Cyclotrons andTheir Applications, Caen, France, 1998, p. 148 (1998) .
3) T. Kubo et al.: RIKEN Accel. Prog. Rep. 33, 236(2000).
4) K. Kusaka and T . Kubo: RIKEN Accel. Prog. Rep. 33,
232 (2000).

235

RIKEN Accel. Prog. Rep. 33 (2000)

Design of the BigRIPS Separator for the RIKEN
RI-Beam Factory Project
T. Kubo, H., Sakurai, K. Kusaka, and 1. Tanihata
In the RIKEN RI-b eam factory project, two new cyclotrons, IRC and SRC, are to be built as post accelerators of the existing cyclotron RRC. 1 ) The cascadeof these cyclotrons will be able to accelerate heavy ion
beams up to e.g., 400 MeV lu for relatively light heavy
ions like oxygen, 300 MeV lu for Kr ions, 200 MeV lu
for Xe ions, and 150 MeV lu for U ions. The expectedbeam intensity is as high as 1 pJ.LA. Such capability
allows efficient production of radioactive isotope (RI)
beams using the projectile fragmentation method,2) inwhich RI beams are produced by a magnetic spectrometer called the projectile-fragment separator. The
separator collects and isotopically separates RI beams
which are produced in heavy-ion collisions with target nuclei, such as projectile fragmentation of various
heavy ions and projectile fission of uranium ions.
Three projectile-fragment separators, which are
named BigRIPS separators, are planned to be built
in the RI- beam factory project, and to be placed after
the SRC cyclotron. The project is divided into twophases called the phase I project and phase II project(or MUSES project). Two BigRIPS separators are intended for use in the phase I project in which ordinary
RI-beam experiments are to be carried out. The other
BigRIPS separator is for use in the MUSES project inwhich RI-beam colliding experiments are to be carriedout. These three BigRIPS separators are to share a
primary heavy-ion beam from the SRC by means oftime sharing. 3 ) In this report, we describe the designof the BigRIPS separator for the phase I project.
As production reactions for the BigRIPS separator, we are planning to use projectile fission as wellas projectile fragmentation , because projectile fission
was found to be very powerful for the productionof neutron-rich RI beams. 4 ) The acceptance of the
BigRIPS separator has been determined considering
the kinematics of the reactions to be used.
The angular spread of projectile fragments is notvery large in the case of projectile fragmentation. The
most severe is the case when light projectiles are used
to produce RI beams which are far from the projectiles.
For instance, the full angular spread is estimated to beabout 40 mr when 11 Li beams are produced from 18 0
beams at 400 MeV lu. On the other hand, the spread isquite large in the case of projectile fission of U beams.
The full angular spread is estimated to be as large as
about 200 mr at 150 MeV lu. In designing the BigRIPS
separator, we aimed to achieve an angular acceptanceof around 100 mr , so that the separator could coverhalf of the angular spread of fission fragments. The
momentum spread of projectile fragments is estimated236

to be about 4% for the case mentioned above. The
momentum spread of fission fragments is estimated to
be as large as about 20%. However , due to the angle
and momentum correlation in reaction kinematics , thespread is reduced to a few percent when the angular
acceptance is assumed to be 100 mr. In the design, we
aimed at achieving momentum acceptance of around
6% , considering the broadening of momentum spread
due to energy loss in the production target as well as
the momentum spread in the case of projectile fragmentation. Larger momentum acceptance allows theuse of a thicker production target . These values of acceptance enable the collection of fission fragments at
an efficiency of about 10%.
The maximum magnetic rigidity (Bp) of the separator was set at 9.5 Tm, considering light neutron-rich RI
beams produced by projectile fragmentation. This Bp
value, corresponding to fragments with A/Z (mass-tocharge ratio) of 3 and energy of 400 MeV lu, is about
26% larger than that of the SRC cyclotron (7.52 Tm).
The maximum Bp value necessary for projectile fission
is estimated to be 5 to 6 Tm.
We chose a mirror-symmetric achromatic systemwith four bends for the BigRIPS separator.
Its
schematic diagram is shown in Fig. 1. The configuration may be written as TQ-D-TQ-F-TQ-D-TQ-FTQ-D-TQ-F-TQ-D-TQ , where TQ, D and F represent
quadrupole triplet magnets , a dipole magnet and anintermediate focus, respectively. Not only the configuration but also the first-order optics are mirrorsymmetric with respect to the midfocus, where thewaist condition should be fulfilled. The wedge-shaped
energy degrader is placed at the midfocus for isotope
separation. We chose the mirror-symmetric achromatic system with four bends , because (1) two bends
allow a high momentum resolution at the midfocus,
hence a better isotope separation, (2) some geometrical aberrations disappear because of the symmetry,and (3) the system has high flexibility in terms of its
optics design. A large value of image magnification at
the midfocus gives rise to the emittance growth of RI

Fig.!. A schematic diagram of the BigRIPS separator.

beams when the ~nergy degrade~ is placed. Hence weaimed at small values around 1. The system shouldhave different operation modes, since two kinds of reactions are to be used.
Quadrupole magnets used for the BigRIPS separator should have not only large apertures but also highfields , because large acceptance and high Bp values are
required. In designing the separator , we assumed theuse of the iron-dominated superconducting quadrupole
magnets, by which high pole-tip fields such as 2.4 T canbe achieved .5) Their aperture and length were determined based on the optics design, in which the maximum pole-tip fields were assumed to be 2.4 T. The
dipole magnets were assumed to be room-temperaturemagnets with maximum fields of 1.6 T and a mean radius of 6 m. The bending angle was chosen to be 30 degrees, considering the constraints of the new building.
The optics design of the BigRIPS separator was
made using the code GIOS and taking into accountthe aforementioned considerations and assumptions.
The basic parameters of the BigRIPS separator are
given in Table 1. The parameters are listed for two
different operation modes of the same system, which
Table 1. Basic parameters of the BigRIPS separator.

~8[mr]High acceptancemode

High resolution
mode

80

40

~<I>[mr]100

80~P/P[O/O]

7

4~Q[msr]

8

3.2

(x/x)

1.02

(x/o) [cm/%]

1.48
3.52

4 .87

(y/y)

1.73

1.21

P/~P*

2380

4770

Max. Bp[Tm]

7.52

9.5

Length[m]42.8* First-order momentum resolution at the mid focus.
A beam spot size of 1 mm is assumed.

-m ay be called the high acceptance mode and highresolution mode. The high acceptance mode has afirst-order momentum resolution of about 2400, almost
achieving the desired acceptance for projectile fission.
This momentum resolution is satisfactory because theisotope separation power is limited due to the energy
straggling effects caused by the degrader. Although
it has smaller acceptance values, the high resolution
mode has a momentum resolution of about 4800, which
is a factor of two better than that of the high acceptance mode. The maximum Bp value of high resolution
mode is 9.S Tm, achieving the desired value for projectile fragmentation. Because of the large acceptancevalue, the correction of optical aberrations is necessary to improve the isotope separation. The important aberrations are the second-order chromatic term
(x/eo) and some third-order terms. The aberration
correction is in progress using sextupole and octupole
magnets.
The superconducting quadrupole magnets of the
BigRIPS separator have large apertures. For example,
the quadrupole triplets between the first and fourth
dipole magnets have a pole-tip radius of 17 cm anda warm-bore radius of 12 cm. These triplets consistof three iron-dominated superconducting quadrupoles
with effective lengths of 50, 80 (or 100), and SO cm.
Their maximum pole-tip fields are about 2.4 T as assumed in the optics design. Design studies of thesuperconducting quadrupoles have been made,6) andconstruction of a prototype triplet is in progress.
References
1) Y. Yano et a1.: Proc. 15th Int. Conf. on Cyclotrons andTheir Applications, Caen, France, p. 696 (1998).
2) B. M. Sherrill: Proc. 2nd Int. Conf. on Radioactive Nuclear Beams, Louvain-Ia-neuve, Belgium, p. 3 (1991).
3) K. Kusaka and T. Kuho: RIKEN Accel. Prog. Rep. 33,
232 (2000).
4) M. Bernas: Proc. ENAM98 Conf. on Exotic Nuclei andAtomic Masses, Bellaire, Michigan, p. 664 (1998).
5) A. F. Zeller et a1.: IEEE Transactions on Applications
and Superconductivity 9, 693 (1999).
6) T. Hirumachi et al.: Proc. 16th Int. Conf. on Magnet Technology, Florida, 1999, in press; T. Kubo et al.:
RIKEN Accel. Prog. Rep. 33, 238 (2000).

237

RIKEN Accel. Prog. Rep. 33 (2000)

Design of a Superferric Quadrupole Magnet for the RIKEN
RI-Beam Factory Project
T. Kubo, T. Hirumachi, T. Tominaka, H. Sakurai, T. Nagafuchi, K. Kusaka, M. Okamura,
T. Tsuchihashi,*l O. Ohsaki,*l T. Senba,*2 and S. Suzuki*2

In the RIKEN RI-beam factory project,l) radioactive isotope (RI) beams are to be produced using
projectile fragment separators called BigRIPS. 2) A
BigRIPS separator is designed to be a magnetic spectrometer consisting of dipole, quadrupole, sextupole
and octupole magnets. The quadrupoles must havea large aperture and a high field gradient, becausea large acceptance as well as high magnetic rigidity are required for the BigRIPS separator.
An
optics design of the separator led us to conclude
that the quadrupoles must be superconducting tomeet the requirements. With respect to the typeof superconducting quadrupoles, we considered two
types: the superferric quadrupole (iron-dominatedsuperconducting quadrupole) which has been developed at NSCL/MSU3 ,4) and the COS(2B) quadrupole.
We have chosen the superferric quadrupole for the
BigRIPS separator, considering the liquid helium consumption as well as the fabrication cost. A prototypeof the superferric quadrupole will be built for R&D
studies. The prototype will be a quadrupole triplet
mounted in a single cryostat.
The prototype quadrupole triplet consists of three
superferric quadrupoles with identical cross sections.
They are installed in a single helium vessel and cooledby the liquid-He bath cooling method. Their schematic
depiction is shown in Fig. 1. The quadrupoles havea pole-tip radius of 170 mm and a warm bore radius of 120 mm. The design effective lengths of thequadrupoles are 0.5, 0.8, and 0.5 m. The maximum

pole-tip fields are chosen to be 2.4 T, corresponding
to the field gradient of 14.1 T /m, because the uniformity of the field gradient is found to rapidly worsen at
higher fields. Correction coils such as sextupole andoctupole coils are to be installed in the gap between
the pole tip and the inner pipe of the helium vessel.
In designing the prototype superferric quadrupoles,
we studied two types which have different quadrupole
coils. One is the race-track type (or £lat-winding type)whose coils can be wound by ordered winding. The
other is the NSCL/MSU type, which is essentially thesame as that developed at NSCL/MSU. 3,4) In this case,the coils are wound by random winding. The reason
for choosing to also study the race-track type is that
it was expected that ordered coil winding would be
more feasible and coil quality could be controlled moreeasily, as compared with the NSCL/MSU-type random
winding. Hereafter, these two types are referred to as
type A and type B, respectively.
The uniformity of the field gradient has been optimized by means of a two-dimensional (2D) magnetic
field calculation, in which the codes OPERA-2d and
OPERA-3d/TOSCA 5) were used. In order to derive
quadrupole fields as well as higher multipole fields suchas 12-pole and 20-pole fields, the calculated fields wereanalyzed by the multipole analysis method, in which
the reference radius was chosen to be 120 mm. The
cross-sectional shape and position of coils were adjusted looking at the 12-pole fields, since this component was expected to most strongly affect the uniformity. The current density of coils was kept at around

300
250
~ 200
~ 150

Iron

100

,// \ A.ir

50

,/

'~

""'(!'(::~\

coilV i\o .':------- ------.---~ - -------- -- -----~::::: ..
Fig. 1. Schematic depiction of the prototype quadrupole
triplet.
*1

*2

238

Toshiba Corp.
Hitachi Ltd.

o

100

200
X

300

400

(rom)

Fig. 2. Octant of optimized cross section for type A (solidline) and type B (dashed line) superferric quadrupoles.

100 A/mm 2 , considering the quench protection and thesuperconducting wire to be used. Care was taken toprevent the interference between the correction coils
and quadrupole coils at the coil end. The optimized
cross sections are shown in Fig. 2 for both type A andtype B quadrupoles. It can be seen that ordered coilwinding is possible for type A, while it is difficult for
type B. Some main parameters for the quadrupoles arelisted in Table l.
Figure 3 shows the 12-pole and 20-pole fields derived
from the 2D calculation as a function of quadrupole
field gradient. The 12-pole and 20-pole fields are shown
as a ratio to the quadrupole fields. It can be seen thatthe 12-pole fields are the most important. The 12-polefields of type A and B quadrupoles behave similarly atfield gradients larger than 12.5 T /m. However at lower
field gradients , the 12-pole fields of type B are muchsmaller than those of type A. With respect to the 2D
calculation, type B has better uniformity than type A.
A three-dimensional (3D) field calculation has been
performed , since end effects were expected to be large
due to the large aperture and the short magnet length.
Table 1. Main parameters of type A and B quadrupoles(0.5 m).

'" 0.54170

B'" 0.53
170

orderly

random

190
127
1500

240
136
1760
104
2300
450
626
450
480

A

Type
Effective magnetic length (m)Pole tip radius (mm)Winding of coil
Nominal current per pole (kA)
Nominal current (A)Nominal turn number
Nominal current den sity (A/mm 2)
Cross section of coil (mm 2)
Straight length of coil (mm)Total length of coil (mm)Length of iron (mm)Outer radius of yoke (mm)

III

1720
440
640
440
475

The calculation was made using the code OPERA3d/TOSCA. In this case, the multipole analysis was
carried out position-by-position along the magnet axis,
and then the derived fields were integrated over theaxis. Figure 4 shows the integrated 12-pole and 20pole fields at a radius of 120 mm . The fields are shownas as ratio to the integrated quadrupole fields, and areplotted as a function of quadrupole field gradient at
the middle of magnet axis. It is can be seen that the
12-pole fields, which make dominant contributions, aremuch larger in low and high field-gradient regions ascompared with those of the 2D calculation. Furthermore, the behavior of type A is very similar to that oftype B quadrupoles. The results of the 3D calculation
indicate the large end effects, as anticipated. In order to understand the end effects, the calculated fields
were decomposed to two components: those generated
by coil contributions and those by iron contributions.
It was found that the large 12-pole fields in the low field
gradient region arose from the effects of the iron poleend , while those in the high field gradient region arosefrom the effects of the coil end part. Furthermore, it
was found that the 12-pole fields in the low field gradient region could be reduced by chamfering the poleends, and those in the high field gradient region could
also be reduced by adjusting the distance between thepole end and the coil end part so that the two contributions could negate each other. The optimization of
the magnet end is in progress.
The superconducting wire for the quadrupole coils
was chosen mainly based on the requirements of low
current operation, hence low helium consumption, andself-protection against quenching. The coils must notbreak down even if all the stored energy is dissipatedinto one of four quadrupole coils. Some of the main parameters of the chosen superconducting wire are listed
in Table 2, and were determined based on the quench

0.006
0.004

L

0.002

blOIS.I _ _

0.004
0.002
~

.Q

b'10(B}0--_........_---_.......__. _ - - -- --,-0.002b'6(B)

o

2.5

5

7.5

g

10

12.5

15

(Tim)

Fig. 3. Twelve-pole (b6) and 20-pole (bID) fields at a radiusof 120 mm derived from the 2D calculation. These fields
are shown as a ratio to the quadrupole fields, and areplotted as a function of quadrupole field gradient g.
Types A and B are indicated in parentheses.

-0.006_-'-/_____ ____ ___---- -- 0.004-0.004b' 10 (A)

/ ,/

0

2.5

5

b' 6 (A)

7.51012.515

gO (Tim)Fig. 4. Integrated 12-pole (b'6) and 20-pole (b'10) fields
at a radius of 120 mm derived from the 3D calculation. These fields are shown as a ratio to the integrated quadrupole fields, and are plotted as a functionof quadrupole field gradient at the center of magnet axis
gO. Types A and B are indicated in parentheses.

239

Table 2. Main parameters of superconducting wire.

Parameter
Insulated diameter (mm<\»
Bare diameter (mm<\»Cu/super Ratio
RRR ofCu
Filament diameter (/-tm<\»

1.15
1.10
6.6

100 - 150
75

Table 3. Calculated results of quench protection.
Quad.

I

L

E, •

Tma ,

Type

(A)

(H)

(MJ)

(K)

V max
(V)

VL.ma,
(V)

b

RnJ

c

(Q)

0.30
670
29
153
26
100
44
170
0.48
110
880
33
a E,: stored energy,b VL.max : maximum voltage between layers,
Rn . t : final resistance of the normal zone.
A

13

B

15

L'

160
'O~

~~

cO-

800
Voltage140........,

120

"

~OJ

I

,ex; H

100

l
I

~

80

.l /

-;:j
~

~

cO

H

OJ OJ

40

UE-<

20

;:j OJ

,.

.....

500

...'.....

300

"

/"

<
0
t-'

rt

400

~

,'-",'-

600

Temperature,::....... - - - - - - - - - .

.ill"

60

~

H
H

:'

700

"

'." ...

200...... ......... -..

PJ
lO

ro

<

100

0

0
0

4

6

8

10

Time (s)Fig. 5. Current decay, temperature rise and voltage development after quenching of the type A quadrupole whose
effective length is 0.8 m.

240protection analysis.
The quench protection analysis was carried out for
the quadrupole with the effective length of 0.8 m , because it has the largest stored energy. For safety, theexcitation current was chosen to be 20% larger than
the nominal maximum value. As the worst case, it
was assumed that the quenching occurs in one of four
coils, while the rest of them remains superconducting.
As the design criteria, the maximum allowable voltage
and temperature were taken to be 1 kV and 100 K ,respectively. The calculated results are listed in Table 3. Quench characteristics such as current decay,temperature rise and voltage development are shownin Fig. 5 for the type A quadrupole. It is shown thatthe quadrupole coils wound with the chosen wire canbe self-protecting.
The basic design of the superferric quadrupoles
which produce a maximum field gradient of 14.1 Tim
over a 120 mm radius with the uniformity of about
0.5%, has been carried out with 2D and 3D magnetic
field calculations. The mechanical design is being studied on the basis of the field calculation.
References
1) Y. Yano et al.: Proc. 15th Int. Conf. on Cyclotrons andTheir Applications, Caen, France, p. 696 (1998).
2) T. Kubo et al.: RIKEN Accel. Prog. Rep. 33, 236(2000).
3) A. F. Zeller et al. : IEEE Transactions on Applications
and Superconductivity 9, 693 (1999).
4) B. Zhang: Ph. D. thesis, Michigan State University.
5) OPERA-2d and OPERA-3d/TOSCA, Vector Field,
Ltd. , Oxford, England.

RIKEN Accel. Prog. Rep. 33 (2000). Estimation of Deposited Heat and Damage by Neutrons on the
Downstream Superconducting Magnet of the Target Assembly .
T. Mukhopadhyay, T. Kubo, and T. Maruyama
When radioactive ion beams are produced by the
Big-RIPS separator, superconducting magnets locatedimmediately after the production target are exposed tointense neutrons with high energy. The cooling capacity of the cryogenic system of the magnet must take
into account the heat deposited by the neutrons on
the magnet. Theoretical estimations of the power deposited by the neutrons on the magnet, assumed to bea solenoid for simplicity, in a geometrical setup as inFig. 1, have been performed based on the measured
or computed production yield of neutrons for several
beam-target combinations. A study of radiation damage, based on the maximum absorbed dose per unit
mass on the magnet, leads to estimates of lifetime ofoperation of the magnet. Similar radiation damage
study on the epoxy of the magnet coil has also been
carried out using KERMA (kinetic energy released inmaterial) values.
First, the computed or measured differential yieldor cross-section for neutron production in heavy ion
collisions with the target material is necessary. Let~(E, 8) be the double differential yield of neutrons as
a function of neutron energy E and the angle 8 of thebeam-target combination. Using the ~(E, 8) values wecalculate the average number of neutrons fi per incident ion, the mean neutron energy £ and the total
neutron power (P) released in the region of space occupied by the downstream solenoid.
The average number of neutrons produced per incident beam particle, covering the space at the entranceof the solenoid, is given by

(1)

I~

do

-----+j
Solenoid

Beam axis

Fig. 1. Cross-sectional view of the target and solenoid
setup.

where Ei-Ef is the total energy range of the neutrons
and 8i -8 f is the angular space covered by the solenoidwith respect to the centre of the target and the beamaxis. Similarly, the average energy £ of the neutron
produced is given by

E = 27r

JJ

E'L,(E, 8) sin 8d8dE In.

(2)

The total power in the space at the entrance of thesolenoid is then given by P = ClonE, where 10 =the primary beam intensity in particles per second andC = 1.60217733 * 10- 13 joules/MeV.
We next proceed to calculate the similar quantities,n' and £, in the space at the exit of the solenoid
after the neutrons pass through the material of thesolenoid. A simple method to carry this out is to
assume that while the neutrons traverse through thematerial of the solenoid, the energy weighted neutron
flux is attenuated exponentially with the distance travelled within the material, which is a current technique in accelerator shielding. This means that thequantity Io~(E, 8)E at the entrance of the solenoid
becomes Io~(E, 8)Eexp( -L(8)/ )"(E)) at the exit of
the solenoid. The distance L( 8) traversed within thesolenoid by a neutron moving at an angle 8 with thebeam axis can be determined easily from the geometry of the setup. For attenuation length )"(E) as
a function of energy E, we have used a set of )"(E)values calculated with RETe code, which is basedon the cascade and evaporation model,1) to interpolate the values of ).. at required energies. In thismethod, iron is assumed to be the only constituent
material of the magnet. With the transformed variable ~'(E,8) = ~(E,8)exp(-L(e)/)"(E)), the new average values (n', E'), and the power (P') at the exit of
the solenoid can be easily calculated. The power loss
within the solenoid is then given by

H = ~p = Clo(n£ - n' £').

(3)

Results are shown in Table 1.
Experimental
measurements 2 ) have demonstrated that such resultsof deposited neutron power based on the theoreticalmodel are overestimated by a factor of 2.4-4.5. Although inaccurate, such results are useful in determining various scaling factors between theoretical and experimental estimates, between cases of thin and thicktargets, and between different geometries. In spite offavorable scaling factors, the high values of depositedheat call for special arrangements for the cold part ofthe magnet .
We next study the distribution of radiation dose deposited per unit mass of the maget, called the gray241

Table 1. Neutron power absorbed in the solenoid. ri =20.0 cm, ro = 48.0 cm, di = 50.0 cm, length= 250.0 cm.
The various cases cited are (i) 400 MeV lu 20Ne beam
on a Cu target thick enough to stop the beam. (ii)
400 MeV lu 18 0 beam on a thin (1 gm/cm 2 ) 9Be target .
(iii) 400 MeV lu 40 Ar beam on a thin (1 gm/cm 2 ) 9Be
target. Intensity of the beam was 10 = 6.24 * 10 12 pps
C= 1 pj.tA) in each case.
Case

fi

E

p

(MeV)

(wt)

fi'

E;'

p'

6.P

(MeV)

(wt)

(wt)

(i)

2.1861151.21330.5

0.3546144.03

51.1

279

(ii)

0.3035312.0694.7

0.0383256.63

9.8

85

(iii)

0.7174340.77244.4

0.0732287.66

21.1

223

value, expressed in Gray (:= Joules/Kg ). To calculate
the gray value distribution, the solenoid is divided into
smaller cells along its length and thickness. To calculate energy loss by a neutron in a particular cell, one
has to account for the energy loss of the same neutron
along its earlier journey in the solenoid. The energy
loss in a cell can be calculated from
6.E = 21f10

JJE~/(8,E)[1-e- tC<B)/,),(E) ]sin8d8dE , (4)where L'.'(fJ , E) = L'.(e, E) * e- 1. (O)/)"(E), lc = path
length in the cell, and ls = path length traversed in
the solenoid before entering the cell.
Based on the maximum gray value estimate and theradiation damage safety criteria of a maximum allowable dose of 1 x 10 7 Gy /year (1 year of operation time:= 20% of 4800 hr) on any part of the magnet and associated coil, we estimate the lifetime of operation of
the magnet , shown in Table 2.
We have also studied the radiation damage to theepoxy of the superconducting coils of the magnets using KERMA values. The purpose of the epoxy is torestrain coil wire motion, which can result in a quench.
Considerable damage resulting in the degradation of
the compressive strength of the epoxy can occur withradiation. Earlier studies 3 ) have shown a 20% reduction in compression strength of the epoxy with a radiation dose of about 2 x 10 7 Gy. For our calculation wetake 1 x 10 7 Gy as the total dose limit for acceptablecoil lifetime.
Table 2. Calculations of yearly radiation dose to superconducting magnet.
Case

Av. GrayMax. Gray

Av. dose
4Max. dose7

Lifetime(wt/Kg)(wt/Kg)(10 Gy/yr)(10 Gy/yr)(Years)

(i)

0.024

0.327

8.29440.11309(ii)

0.00730.06442.516

0.022345(iii)

0.0192

0.189

6.63550.065315

242

Table 3. Calculations of radiation dose to superconducting
coil epoxy (by KERMA). Cross-section set used wasthat of case (iii) in Table 1.
Coil angle

Yearly Dose

Lifetime

Distance (em)(Degree)7(10 Gy)(Years)64

10.1705664

100.030133

64

200.0043

231

64

30

0.0010981

100.1005

10

Target-to-Coil35

The calculation is similar to that of a dose to a tissue
in biological applications using KERMA values. The
KERMA is defined as the expectation value of the kinetic energy transferred to the charged particles perunit mass at a point in matter , whereas the KERMA
factor refers to the KERMA per unit neutron fluence.
The partial KERMA factor for a certain secondary
charged-particle type is obtained from the product of
the cross section [b] and the average energy [MeV], inunits of b·MeV /atom which can be converted to the 81
unit of Gy·m 2 .
Only the main molecular component in stycast
epoxy, butyl glycidyl ether, (C 4 H lO 0 2 N 2 )n, where n
is a large number, is considered in estimating thedamage. Tables of KERMA factors for H, C, N,
and 0 are available for neutron energies of 1 Me V
to 150 MeV from Los Alamos T2 group Information
Service. 4 ) These factors are weighted by stoichiometric ratios , and then summed to obtain the effective
KERMA value for the molecule as a function of neutron energy. For neutrons with energy higher than
150 MeV, these factors are extrapolated.
The energy delivered by neutron collisions to a 1 cm 3
sample of epoxy placed at a distance and angle fromthe neutron source can be calculated using

D = Ionotp x 10- 3

J,,£(E, no)K(E)dE,(5)

where K(E) in Gy·cm 2 is the effective KERMA value
in epoxy at energy E, no is the average solid angle subtended by the sample at the source, t in sec is the effective operation time in a year (960 hr) and p in gm/cc
is the density of the epoxy. The results, as shown in
Table 3, show reasonably acceptable values.
References
1) N. Fukunishi: private communication.
2) E. Baron, L. Bianchi, J. Dural, and C. Grunberg: Proc.
3rd Europe Particle Accelerator Conf., Berlin, 1992,
Vol. 1 (Editions Frontiers), p. 1555 (1992).
3) R. Ronningen, B. Mukherjee, and A. Zeller: NSCL Report 1998 (unpublished).
4) T2 Information Service: http://t2.lanl.govIRIKEN Accel. Prog. Rep. 33 (2000)

Shielding Design of RIKEN RI Beam FactoryN. Fukunishi, S. Ito, Y. Uwamino, and Y. Yano
We have studied the radiation shield of the RI
Beam Factory for two years. New experimental results
were obtained this year, which are very useful forthe precision check of our method of estimating theradiation dose. One of these results are from shielding
experiments performed with 400-MeV lu 12C beams
accelerated by the RIMAC of the NIRS. Two of theauthors (S. 1. and Y. U.) contributed to one of theseexperiments. We summarize in Table 1 the comparison
between the experimental results and our estimatedresults. We find that our method reproduces wellthe experimental results, except for the O-degree
direction, where we find a large discrepancy between
the estimated results and the experimental results.
This discrepancy comes from the fact that we neglect

the diffusion effect of neutron flux in the shielding material due to the multiple scattering of neutrons in
the present estimation. The diffusion effect is marked
when the distance from the source to the shield issmall (1.5 meters in the experiment) in the O-degreedirection shielding. We estimated the reduction of
the radiation dose due to the diffusion effect with the
RETC-3step code. 3 ) The reduction factor is 43% for a
1.5-meter-thick shield of normal concrete. The shielding thickness in the experiment is 2.8 meters. As thenumerical simulation for the actual experimental setup
is too time-consuming, we did not execute it.
Other useful experimental results were given
by Kurosawa et al. 4- 6 ) They measured the double10

Table 1. Comparison of the shielding calculation values
with experimental values. 1 ,2) The beam intensity is
3 x 108 pps except for the first two data (1 x 108 pps) .
Quantity L is the distance from the source to the point
where the radiation dose was measured. Quantity t
is the thickness of the shield (normal concrete). Angle () refers to the angle from the beam axis. The
unit of effective dose is j.LSV Ih. (* 380-cm-thick normal concrete + 50-em-thick iron).

1~ 1 0°
C/')

Obs.

5.0

280

0.00

66

498

10.0

505*

0.00

1.5

1.26

13.86

286

13.38

16.8

24.9

12.98

268

21.48

13 .9

Calc.

19.7

12.3 8

256

30.56

6.5

13 .6

12.12

250

40.29

3.15

5.66

12.40

256

54.95

0.75

1.02

"' ,"'....

I

1 0'1 ::j \ ',:

t5
10'
Q)

,'.

" \

(- ",,,--,-,,.
,~\. /.,ofI.,,I,,,• IO

W-: ,:,- :!/ .' . . . . ' . \ . . . .

,.,. I 'O--~7"'", -~.a.:~=-~=~__,:~~:: :.::-: .....• , __ :::-.., ,._..; ;.\ .. \ ....

1--.
/.:-,';+;" : II

::1.

-Q)

.-

teem) e(d~g.)-.

..--..

'

'.

"

:~,:~

2

'!I:,"
IL,

• ...

.

' , I'.... .:-' :,' : . \ ~:: f , . ' 0:y.., ..''

I'

"

I

...

"

'."
\
I
,

" :: \ i :,== ~:j~ . ,.. . '-I,i:..','::",\------- A=5m
_ •.• - A=7m';.' ,/-:'r'- . -. - A=9m

:'.,

J~
-----A=15.m'.
----2.5mlcroSv/h.

til.:·---A=llm... - A=13m
I..

,./.7/..\. . ,":.' I , • . " \
'f"/'

'.

".;
~ II'

i~I :. .

~L(m)~----------------------------------~

50

100

:: \', "," I' \

I

\

"

I"

:'," '., \

.

150

200

,

1:\,

': \ ',\250

4> (degree)
Fig. 1. Effective dose distribution on the SRC roof. The
position on the roof is given by the polar coordinates R
and ¢. The origin is just above the machine center of
the SRC. At the extraction point , the beam direction
is 150 degrees.

~1},~$llWtMl lron shieldP',) . ,. I concreteFig. 2. Plane figure of the radiation shield of the Big-RIPS. We assume that secondary neutrons areproduced at the "albedo point". The "albedo surface" determines the injection and scattering anglesof the neutrons.

243differential neutron yields for' various combinations ofbeams and targets. From these experiments, we candetermine how the radiation dose depends on the mass
number and the energy of the ion that hits the target.
Our speculation was that the effective dose which originated from a heavy-ion beam was proportional to theion mass and the square of the ion energy per particle.
The series of experiments revealed that our speculation
was valid. We hence chose a 300-MeV /u-Kr beam asa model beam for the shielding design of the RIBF because the radiation produced by this beam is predicted
to be the most serious concern in the RIBF.
Here, we shall explain some results of the shielding
calculations. We illustrate in Fig. 1 the effective doseon the roof of the SRC room, which is 3-meter-thicknormal concrete. In addition, there also exists a
3-meter-thick local shield of normal concrete placed
just above the EDC of the SRC. The EDC is assumed
to be the main source of radiation. We found that a
6-meter-thick shield of normal concrete is sufficient fora beam loss of 10 pnA. Another example is the shieldof the Big-RIPS which is shown in Fig. 2. Downstream
from the second bending magnet, secondary neutrons
are the most serious radiation. The words "secondary
neutrons" indicate the neutrons generated by theneutrons bombarding the iron shield. To estimate
the reflection rate of radiation on the iron shield,
we calculated double differential albedo functions of
the effective dose using the HETC code. Results
are shown in Fig. 3 for the case when neutrons are
injected into the iron shield at an injection angleof 75 degrees. The design of the local iron shieldshown in Fig. 2 was determined taking into account
this effect. More detailed aspects of our estimation244~ 10° r-- -- - - - - - - - - - - - ,:::::;;,
Q)

en

o

o

Q)

1; 10.

1

()

~

iii
'0
Q.)

en 10.

2

a:
c

o

U
Q.)

==:~1566liJd3~)-·····f=28.125 deg.

_ .... f=39,375 deg.
- . _ .. f=50,625 deg.
- • · f=61.875 deg.
. . ... f= 73,125 deg.
----·f=84.375 deg.

115
a: 10'3 0~~~u50~~~1~00~~~15~0~~

Angle e (degree)
Fig. 3. Double-differential albedo functions of the effective
dose. The source neutrons are from the experimental
results of a 400 MeV lu 20Ne beam on a thick Cu target(0 degree). The shielding material is iron in this case.

are summarized in Ref. 7.
References
1) Two O-degree data are from Y. Kumamoto: private
communication.
2) Other data are from S. Ito et al.: private communication.
3) P. Cloth et al.: Jiil-2203 , Kernforshungsanlage , Jiilich(1988) .
4) T. Kurosawa et al.: J. Nucl. Sci. Technol. 36, 1 (1999).
5) T. Kurosawa et al.: Nucl. Sci. Eng. 132 , 30 (1999).
6) T. Kurosawa et al.: private communication.
7) N. Fukunishi et al.: Proc. SAST99, p. 349 (1999).

RIKEN Accel. Prog. Rep. 33 (2000)

Refinement of Accumulator Cooler Ring Lattice Design
K. 0 htomo and T. Katayama
Preliminary lattice design of the Accumulator
Cooler Ring (ACR)l) has been focused on the accumulation and cooling of radioactive isotope (RI) beams.
Beam momentum spreads of 8p/p = ±0.5% after passing through a fragment projectile separator (BigRIPS),
will be reduced to 8p/p = ±0.15% by a debuncher
cavity2) located 80 m downstream of the BigRIPS.
Devices for multiturn injection and RF stacking areneeded to enhance the beam current. Then beam emittance and momentum spreads should be cooled by theelectron cooling and stochastic cooling devices in the
ACR. The lattice of the ACR should be designed bytaking the following device constraints into account:(1) The electron cooler (EC) requires a long straightdispersion-free space (over 12.0 m long). The horizontal betatron function at an EC should be less than 5 m
because an electron beam size covers the RI beam size.
(2) Stochastic cooling devices require a few pairs ofdispersion-free spaces for a pickup and a kicker, andthe phase advance of the betatron oscillation between
them should be nearly k7r /4 (k: odd).
(3) Multiturn injection requires sections where thephase advance of the betatron oscillation is nearly 7r,
to arrange kickers and septum magnets.
(4) RF stacking requires a dispersion in the multiturn injection section and a space for a tunable RF
cavity.
(5) Accumulation of high current beams requires alarge acceptance in the horizontal plane (Ex = 125 7r .
mm . mrad) and a large momentum spread(~p/p =±2.0% ).

Table 1. Parameters of the ACR.
Circumference
Max. magnetic rigidity
Max. beam energy (A/ Z = 2.3)
Injected beam emittance (Hor./Ver.)
Injected beam moment urn spreads
Stored beam emittance (Hor./Ver.)Stored beam momentum spreads
Betatron tune (Hor.jVer.)
Transition gamma
Max. beta functions (Hor.jVer.)
Max. dispersion

168.4836 m
8Tm
400 MeV /u
10/10 7r' mm· mrad±0.15%
125/10 7r' mm· mrad
±2.0%
3.440/3.540
4.533
28.58 m/28.04 m
3.96 mRefined design of the lattice is shown in Table 1 andFigs. 1 and 2.
The ACR lattice consists of four arc sections, twolong straight sections and two short straight sections,as shown in Fig. 1 and is described as follows:
ACR = STRL- ARC- STRS- ARC-STRLARC-STRS-ARC,
where STRL denotes a long straight section, STRS a
short straight section and ARC an arc section.
An ARC is symmetric and is based on the FO DO
lattice cell.
ARC = QF-B-QD-QD-B-QF-QF3-QD3(IN J)-QD3-QF3-QF-B-QD-QD-B-QF,
where QF and QD are the main focusing andBeam direct i on
OUT

•

l6pOO

I

I

6600

I

I
Of1 001 QF2\5.~~~~~--------~---------~
1i

Stochast i c I
Kickerii

iY=35.6m

I

I
I

I

i

-----------------r--x-=~'--~------~J743
Stochast ic

Pickup!

Electron l Cooler-E3----tlllt-e-A..sz~ ........~--~.

Fig. 1. The layout of the ACR.

245

Fig. 2. Twiss parameters. The periodic solid line represents the horizontal betatron function, the periodic
dashed line the vertical betatron function, the periodic dotted line the dispersion function, the increasing
dashed-dotted line the horizontal phase advance andthe increasing solid line the vertical phase advance.

Fig. 3. Tune diagram. Operation points are represented bya thick bent line.

defocusing quadrupoles, respectively, QF3 and QD3
the dispersion adjustable quadrupoles, and the B bending magnets. The drift space between QD3s is assumed
as an injection point. The ARC functions are assumed
as dispersion suppressers. Four families of sextupoles
are installed each drift space for chromaticity correction.
The long straight section is defined as follows:
1

STRL = -QF2-QDI-QFI-QFI- QDI- QF2-,
where QF1 , QD1 and QF2 are quadrupoles. The
triplets make the horizontal betatron function at thesymmetry point less than 5 m. The middle straightsection , which has a length of 15 m , is assumed tobe the position of the electron cooler or an equipment
for experiments. At both end straight sections, of 6 mlength, stochastic cooler devices and extraction kickers
are installed.
The short straight section is defined as follows:
STRS = -QD2- QD2-,
where QD2s are quadrupoles to adjust the tune andbeta functions ' amplitude at STRS. A tunable RF cavity will be located in this section.
Horizontal tune is selected to be nearly a half integer because the betatron tune advance between every
opposite pair of straight sections become nearly a quarter integer, i.e., constraint (2) is satisfied (Fig. 3). The
large acceptable momentum spread operation makes
the half integer stop band large. It causes a betatron
modulation with a different momentum. However, themodulation amplitude was turned to be at a tolerable
level.
Dynamic aperture of the lattice without a horizontal or vertical orifice has been calculated (Fig. 4).

246

0.0 - - ~ -'-"
-/0.
-8.

Horizontal ratio

Fig. 4. Dynamic aperture with a bare lattice. Number
indicates the ratio of betatron amplitude to normalized horizontal and vertical emittance of 125 and 10
7!'·mm·mrad, respectively.
Solenoids and deflections by troidals of the electron
cooler causes the dynamic aperture to shrink but nosevere influence is noted under the condition where afirst ordered compensation had been added.
Discussion about the momentum compaction factor
between stochastic cooler pickup and kickers to shorten
stochastic cooling time3 ) is underway. The scalable
transition gamma lattice 4 ) will be considered in future
research.
References
1) K. Ohtomo et al.: RIKEN Accel. Prog. Rep. 30, 211(1997) .

2) K. Ohtomo and T. Katayama: RIKEN Accel. Prog.
Rep. 31, 225 (1998).
3) M. Wakasugi: MUSES Meet.
4) A. Dolinskii et al.: Proc. European Particle Accelerator
Conf. '96, p. 596 (1996).

RIKEN Accel. Prog. Rep. 33 (2000)

Development of ACR Electron Cooler (2)T. Tanabe, K. Ohtomo, T. Rizawa, and T. Katayama
The highlight of the cooler design in the accumulator
cooler ring (ACR) in MUSES project 1 ,2) is the gun section which utilizes a He-free superconducting solenoidwith an output of 4 T. To optimize the cost and uniformity of the solenoid field, a smaller gun and an acceleration tube are preferred. However, without thepossibility of placing vacuum pumps in the vicinity of
the cathode, high-vacuum conductance must be maintained through to ensure ultra-high vacuum (UHV.)
Poor vacuum would cause contamination of the cathode surface, lowering of the discharge limit due to ahigh voltage (HV) , and an increase of unnecessary radiation hazard. Both Egun 3 ) and SAM 4 ) are used to
examine the behavior of an electron beam (e-beam) to
optimize the design. Figure 1 shows results of EGUN
simulation with the current design.
Optimization of the design of the magnetic shieldand solenoids is directed toward the uniformity of the
field over the acceleration area, the minimization of
the shield thickness , and the reduction of the adiabatic
parameter, which is defined as

_

27r~

eB

(2)

.

EGN : 3 . OJSCYCLE=

1:fIi: ~S....-;(
240r

SC Coil-\

E-t.... 3

/

480

720

960

1200

1440

1680

RI EC 99 / 08 / 27

Fig. 1. EGUN simulation of the electron gun section.

-0.2

Nonnal Coil

/

0.2

0.4

0.1

t

i....

0.08 f?
n

'II

,

1\/

-/,y
0

-

:

0.06 ~EAo

A cross-sectional view of the design of an electron
gun, an acceleration tube, a superconducting solenoid,
a warm solenoid, and magnetic shielding are delineatedin Fig. 2. The magnetic field distribution and the adiabatic parameter are shown in Fig. 3.
The electrons are further perturbed when they passthrough the toroidal sections. This perturbation isobserved in electrons which are displaced from theequilibrium axial trajectory. When the electrons passthrough a toroidal magnet, additional drift velocity
appears which is inversely proportional to the squareof the radius of the axial electron trajectory in thetoroidal section. 5) Hence, the discontinuity of the magnetic field at the entrance/exit of toroidal magnets generates additional transverse temperature which can be

o

5 -

0.12

(1)

where B is the solenoid magnet field and Ae is the spirallength of the cyclotron motion\

61

x = ~I:!I ,.l\e -

Fig. 2. Layout of (1) a superconducting solenoid, (2) awarm solenoid and (3) magnetic shielding.

O.O~ ~
It"\. . . r--.~

""-1-

0.6

0.8

Z

[m]

0.02 ~

0
1

1.2

1.~

1.6

Fig. 3. The longitudinal magnetic distribution and the adiabatic parameter .

reduced by increasing the toroidal radius and decreasing the adiabatic parameter at the entrance/exit of
toroidal magnets.
The initial design of the ACR collector was basedon the TARN II collector. Various improvements havebeen incorporated during the past year. The geometryof the new collector section is given in Fig. 4.
The ratio of the current density of the reft.ected secondary electrons that escape a collector to those of theincoming beam is proportional to 5 )jr~f ~ a e (<pmin) 2
J

7r

Ueol

Beot
B<p min,(3)

where j is the incoming beam current, a e ~ 1 is the secondary emission coefficient, Beol and Ueol is the magnetic field and voltage on the collector surface, respectively, ¢min is the minimum poteintial on the axis andB<pmin is the magnetic field in the region of minimum
potential value. The types of modifications applied
were as follows:(1) The collector diameter was increased to reducethe magnetic field on the collector surface, Beol.
(2) To increase B<pmin, a permanent magnet coil was
247

Table 1. Parameters of ACR-EC .
Acceleration Voltage
Magnetic Field (gun/cooling)
Field Uniformity (gun/cooling)
Cathode Diameter
Maximum E-Beam Current
Gun Perveance
Anode-Cathode Voltage
Main Solenoid Length
Toroidal Angle / RadiusCollector Efficiency

30,,-, 250 kV
4 T / 0.2 T
1 x 10- 4 / 2 X 10- 5

12.7 mm
4A

0.79 J.LP
30 kV
3.6 m

90° / 1.5 m> 99.98%

Fig. 4. The design of the collector. 1 indicates the drift
chamber , 2 the deceleration tube, 3 the repeller, 4 thecollector electrode, 5 the solenoid of electron cooling, 6magnetic shielding, 7 the permanent magnet coil placedat the collector entrance, and 8 the permanent magnet
coil placed on the collector surface.
placed inside the repeller electrode with a magnetic
field of 2 kG.
(3) A permanent magnet coil was placed on the collector surface to reduce Beol.
(4) The collector radius was reduced at the entrance
to shift the position of the virtual cathode to a regionof higher magnetic field.
The collector perveance is estimated as Peol =I/Ueol 3/2 ~ 25 rv 30 p,A/V 3 / 2 . The permanent magnets produce a negative radial magnetic field on thecollector surface in the region of 44 cm < z < 51 cm(magnetiG-insulated region). Consequently, the current loss was reduced by one order of magnitude compared to the old design.
A diagnostic setup for an e-beam can be separated in two categories of devices: Conventional andspecial ones. The conventional diagnostic devices
measure electrode potential, e- beam current and ebeam loss current. The special devices are used forthe measurement of the transverse electron temperature, the parameters of the neutralized electron beam ,and the characteristics of the secondary electrons andions.
The details of the designs have yet to beestablished.
Table 1 shows the latest parameters of the device,248

I----------l1mFig. 5. Cross-sectional view of the MUSES-ACR EC . The
gun section is on the right-hand side and the collector
section is on the left-hand side.
and the cross-sectional view of the entire EC system isshown in Fig. 5.
References
1) T. Katayama et al.: Proc. EPAC98 , p. 529 (1998).
2) T. Tanabe, K. Ohtomo, T. Rizawa, and T. Katayama:
RIKEN Accel. Prog. Rep. 32, 212 (1999).
3) B. Herrmansfeld: SLAC 226, NC. 28.
4) M. Tiunov, B. Fomel, and V. Yakovlev: Preprint INP,
Novosibirsk, p. 85 (1996).
5) E. Syresin: Nucl. Instrum. Methods Phys. Res. A 391,
114 (1997).
6) MUSES Conceptual Design Report, RIKEN, Chap. 4(1997) .

RIKEN Accel. Prog. Rep. 33 (2000)

Study of Pickup for Stochastic Cooling
N. Inabe, M. Wakasugi, M. Kanazawa, and T. Katayama
Stochastic cooling 1 ) is used for beam cooling of Accumulator Cooler Ring (ACR) .2) The cooling timein ACR should be short (rv 100 ms) since fast beamcooling must be realized for Radioactive Isotope (RI)
beams with very short intrinsic lifetimes. The stochastic cooling system is composed of pickups, preamplifiers , amplifiers , filters , and kickers; it forms a feedback
loop from the pickups to the kickers. In order to obtaina short cooling time a large gain, a low noise and a wide
frequency band are required for the system. 3 ) To develop such a system we need a highly sensitive pickup,
a low-noise preamplifier and a large gain amplifier fora wide frequency region (0.3-2.0 GHz). As the firstdevelopmental step , we fabricated a pickup and tested
it using a beam from the HIMAC 4 ) synchrotron.
Figure 1 depicts a pickup system. The pickup system is composed of 16 pairs of electrodes, a groundbox, and a vacuum chamber. Each electrode is a loop
typed coupler and its length (50 mm) is chosen so as tobe maximally sensitive around 0.5- 1 GHz. The electrode width (81 mm) and gap (60 mm) are determinedso as not to disturb HIMAC beam. The signal picked
up by the electrode is sent to two terminals locatedat either edge of the electrode through a stripe-line ofterminal(downstream)
terminal(upstream)
configuration of electrodes (side view)

50 0 composed of the electrode and the ground box.
Each terminal is connected by a coaxial cable (Dipsol Co. Ltd. ; Cu-s5DDs-08) having a wide frequency
band and low outgas and the signal is sent outside
the vacuum chamber through an original feed-throughconnector. Since the voltage of the output signal fromthe terminal depends on the beam velocity, we prepared two terminals so that we can choose the larger
signal of the two terminals. When using the system,
the terminal with the smaller signal is terminated by
the 50-0 terminator.
In order to have adequate vacuum pressure (rv 10- 10Torr) in the synchrotron the vacuum chamber has two
ion pumps (400 lis each). Before the pickup system
was installed into the synchrotron we backed it. The
baking temperature was raised to 180°C over two days
and kept at the temperature for another two days. One
week after the end of baking, the vacuum pressure became 2 x 10- 9 Torr. One month after installation thepressure was 5 x 10- 10 Torr.
A beam test for the pickup system was performed
using a carbon beam of 290 MeV /u from the HI MAC
synchrotron. The intensity of the beam was 1.9 x 109
particles per second and it was very stable. In the test
we measured signals picked up by the electrodes for abunched beam and a coasting beam after acceleration
with respect to the time and frequency domains. In themeasurement for the coasting beam the RF voltage ofthe cavity was turned off. Figure 2 shows an electricalcircuit for the measurement. A pulse from the synchrotron produced at the finishing time of acceleration
was used as a gate signal for the measurement. For
the measurement of the bunched beam, an RF signal
was used to mark the time origin. The signal fromthe electrode was sent to a sampling oscilloscope forthe time-domain measurement and a spectrum analyzer for the frequency-domain measurement. In themeasurement , when the signal from one terminal was
Frequency domain

ion pump

ion pump

Fig . 1. Schematic depiction of the pickup system.

Fig. 2. Electrical circuit for measurement of the pickup
signal.

249

measured, the other terminal was terminated. Since
this measurement was the first test of the pickup system, we concentrated on observing any signals and did
not use a preamplifier.
Figures 3 and 4 show the time- and frequency- domain signals for the bunched beam. The interval between peaks in Fig. 3 shows the time interval between
bunches. The interval between peaks in Fig. 4 shows
the RF frequency of the synchrotron. The measured
values of 166 ns in Fig. 3 and 6 MHz in Fig. 4 wereconsistent with RF frequency set for the synchrotron(5.998 MHz). In Fig. 4 one can see that the peak heightdecreases as the frequency becomes higher. The bunch
length of the beam was long and the electromagnetic
field produced by this long bunched beam has a strong
component in the low- frequency region. The tendency
of decreasing peak height results from the long bunch
length.
We attempted to reproduce the time-domain signal0.02,-,. 0.01

:>
'--"
Q)

Oil

~ 0.00

o

:>
-0.01

-:--'--"----'----'--400-'-:--1-.-L-.--'----'--:6..J...00~-0 .02 0'--"----'-----'---'--2--'00

Time (ns)Fig. 3. A time-domain signal from an electrode of the
pickup system.

1.010'2-1.510.2-2.0 10. 2

L.....J...-'--.&....J..~.........-L............__'_...L.....I..__'_.L-.J.__'_..........-.I-...........~

o

20

40

60

80

100

120

Time (ns)Fig. 5. Calculated and measured time spectra for bothterminals of one electrode.

on the basis of theoretical calculation. 5) In the calculation, the distribution of the bunched beam wasassumed to be the Gaussian part plus the fiat partsand frequency up to 100 MHz was taken into accountfrom Fig. 4. The widths of the Gaussian and the fiat
part as well as the sensitivity of the pickup were parameters for the reproduction. Here, sensitivity is aquantity defined by Vout/Ibeam, where V out is the output voltage measured in the sampling oscilloscope andIbeam is the average beam current. In Fig. 5, the reproduced spectra for the two terminals of one electrodeare shown with measured signals. In the figure, widthsof the Gaussian and the fiat parts are common for thetwo curves. The obtained half-width of the Gaussianpart is 2.0 m and that of the fiat part is 0.85 m. The
obtained sensitivity of the pickup around 100 MHz is
5 n for the upstream terminal and 1.5 n for the downstream terminal. These values are rather high compared to the ones from the theoretical calculation.
Unfortunately, we can not measure the frequency
spectrum of the coasting beam because the signal isvery small. However, this is not inconsistent with thetheoretical calculation. In the next experiment scheduled on January in 2000, we will measure the spectrum
by using of a preamplifier and obtain a sensitivity up
to 2 GHz. Moreover, we will examine how to combine signals from various electrodes using the pickup
system.
References

o

20

40

60

80

100

Frequency (MHz)Fig. 4. A frequency spectrum from an electrode of the
pickup system.

2501) S. van der Meer: CERN Report, CERN/ISR-PO/72-31(1978).
2) K . Ohtomo et al.: Proc. 17th PAC , Vancouver, May,
p. 1072 (1997).
3) N. Inabe et al.: Proc. 6th EPAC, Stockholm, June,
p. 1037 (1997).
4) Y. Hirao et al.: Nucl. Phys. A 538, 541c (1992).
5) D. A. Goldberg et al.: LBL Report, LBL-25924 (1989).

RIKEN Accel. Prog. Rep. 33 (2000)

The Ferrite Test Cavity for MUSES (II)K. Ohtomo, T. Rizawa, and Y. Chiba
We reported on a ferrite test cavity in the last issueof this annual report,1) used for measuring the characteristics of ferrite at the same high rf power level asthat planned for the booster synchrotron of the MultiUSe Experimental Storage rings (MUSES) project; anaccelerating cavity is required to generate 25 k V in
the frequency range of 25 to 53 MHz. In this issue, wereport on the further improvement and calibration of
the system. Figure 1 shows a schematic of the cavity.
Improvement of the system: In the first step of theexperiment with the cavity, unstable behavior of the
Q value of the cavity itself, without the ferrite, wasidentified. This behavior was caused by a malfunctionof the contact fingers used on the cylindrical surfaces
a, b, c, d and e shown in Fig. 1. Improvements weremade by replacing the contact fingers with a Helicoflex
metal gasket at a and c, a flat face metal-metal contact
at b and another type of contact spring at d and e.
Calibration of the system: The system is divided
into two parts, as seen Fig. 1, by taking the junction
plane at S. The admittance of the upper half with theferrite is denoted by Ym and that of the lower half,
by Y c. The entire system is formed by the parallel
connection of Ym and Y c. Ym is inductive at theresonance frequency and Yc , capacitive. Hereafter, G
and B denote the real and imaginary parts, respectively, of the admittance Y, e.g. , Ym = Gm+iBm andY c = Gc + iBc. The resonance condition is given by
Bm = -Bc.

b

6

a 5

unit:1TITI

II
II
/I

//

~

110

~

200

c

600

l:ferrite ring
2:ferrite vessel
3:tuning capacitor Ct
4: impedance matchingcapacitor em
5:bias conductors
6:removable cross bar
7:voltage and current
monitors
8:voltage monitor
9:rf input terminal
lO:water cool ing pipe

Fig. 1. Schematic diagram of the ferrite test cavity.

The relative permeability, /-L, and magnetic Q value,
Qm, of ferrite are determined from Ym. This processdepends on the electrical model describing the ferrite vessel containing the ferrite. The simplest model is

I Ct=3~

1.0 ~~---+~~-+~- +~~----4-------+---1

20

(a)

Frequency [MHz]

(b)

30

40

50

60

Frequency [MHz]Fig. 2. (a) Real part ofYc and (b) imaginary part ofYc. Circles indicate calibration points, e.g., points
on the dotted line labeled J..L4 represent measurements with a reference stub corresponding to a J..L of
4. Points with the same Ct are connected by a solid line. Ct varies from 38 to 60 with an intervalof 2. Squares indicate points corresponding to a J..L of 25, which are estimated using the transmission
line approximation.

251

one that ignores the radial dependence of /-L due tothe bias field and assumes a low frequency limit. This
yields an effective /-L by (f· Bm '/-Lo' t ·In(b/a))-l and
Qm by IBm l/Gm, where f is the measuring frequency,/-Lo is the permeability of vacuum, and t , b and a are
the thickness and the outer and inner radii of the ferrite ring, respectively. We use a model based on thetransmission line approximation, in which the vessel istreated as a radial mode transmission line and a radially constant /-L is assumed. This model is appropriate
for the frequency range studied here and can be solved
numerically.
With the value of voltage, V, across Ym, and input power , P, at the resonance frequency, Gm is directly obtained from (P /V2)-Gc using a precalibrated
value of Gc. Bc is dependent on the frequency and thevalue of the tuning capacitor, Ct, while the impedance
matching capacitor contributes only a small correction. Bc can be estimated with reasonable precisionon the basis of the transmission line calculation but
Gc must be estimated by measurements, because of
the contribution from the resistance of the structuralcontact surfaces and the loss factors of the tuning capacitor. Therefore, both quantities were estimatedusing calibration measurements as a function of frequency and division number of the revolution dial

252of the tuning capacitor.
Four types of reference admittance are provided.
They are nearly equivalent to the admittance of ferrite
rings (8"outer diameter, 5" inner diameter and l"thick)with /-L equal to 1, 4, 8.5 and 16.5. They consist of
simple coaxial stubs whose admittance, Gr + iBr, iseasily calculated. Replacing the ferrite vessel with areference stub, the resonance frequency and the conductance of the entire system , Gs, are measured using
an impedance analyzer connected to the junction point
on plane S. Thus, Y c is determined at the resonancefreq uency as Y c = (Gs - G r) - iBr. For each reference
stub , calibration is made at 12 positions of the tuning
capacitor between the number of dial divisions Ct = 38
to 60, which corresponds to a real capacitance of 642
to 70.5 pF. Results are shown in Fig. 2 (a) for the realpart and Fig. 2 (b) for the imaginary part.
/-L and Qm are calculated from the measured databy linear interpolation between the calibration points;
measured data are f (MHz) , Ct (division) , V (volt)
and P (watt).
References
1) K. Ohtomo and Y. Chiba: RIKEN Accel. Prog. Rep.
32 , 218 (1999).

RIKEN Accel. Prog. Rep. 33 (2000)

Development of the Kicker Magnet for BSR
T. Ohkawa, T. Katayama, M. Wakasugi, and Q. You
In the booster synchrotron ring (BSR), kicker magnets are used for ion-beam injection and ion-beam andelectron-beam fast extraction. The injection and extraction kicker field must rise and fall from approximately 5% to 95% of full strength during the timeinterval between bunches (about 50 ns) .1) The highperformance of the kicker magnet is crucial for the efficiency of beam injection and extraction. In this paper, the development of a kicker magnet for BSR ispresented.
We have adopted the Pulse Forming Network(PFN)- type kicker magnet which is often used to generate a high magnetic field with a rapid rise and falltime. The characteristic impedance Z is related to the
inductance Lo and capacitance Co of the unit cell by(1)

Z = y'L o/2C oand the transmission time Tm of the total magnet is
calculated byTm =Ny'2L oCo,

The characteristic impedance and the transmission
time are measured using a low-voltage short pulse. A
schematic of the measurement system is depicted inFig. 1. The kicker magnet and pulse generator areconnected by the 50 n transmission cable. In orderto match the impedance, a matched resistor R1 is installed between the inlet of the magnet and the 50 ntransmission cable and the outlet of the magnet is terminated in the matched resistor R2. The reflected signal follows the input pulse and can be presented in
the same oscilloscope record. The amplitude of the reflected pulse serves as an indicator of the matching. In
the ideal case the pulse travels to the matched resistor and there should be no reflected pulse. Figure 2
presents the results of the 0.5 V pulse with a flat topof 1 I1S and a rise time of 65 ns. Figures 2 (a) and(b) show the reflected voltage pulses when one of thematched resistors Rl and R2 is changed while the other(2)

50 .Q transmission cable

where N is the cell number. The relationship between
Z and Tm is obtained by Eqs. (1) and (2) asTm(3)= NLo/Z.

Therefore, decreasing the impedance causes an increase of the transmission time. In order to generatea magnetic field of the design value in a core gap of
30 mm, PFN voltage is required up to 100 kV. Whenthe PFN is added with 100 kV, the kicker magnet can
produce a magnetic field of 0.084 T with a flat top of
1 J.ls and a rise time of 65 ns. The design parameters arelisted in Table 1. The height and width of the kicker
magnet aperture are 30 mm and 130 mm, respectively.
The kicker magnet has a transmission-line structure ofnine cells and the characteristic impedance is 25 n.

Fig. 1. Schematic of the measurement system.
0.05

-..

G

j- R I =25 Q

0.025

I

CI)

~

- - R I =27 0~> -0.025,- - R I = 28 0

-0.05

--500

Time (ns)0.05

DESIGN VALUE
30mm
130mm
225 mm90.136 !lH
108.9 pF
25 Q
0.084 T
2000 A
100kV
65 ns

terminated(a) R1 is changed

Table 1. Design parameters for the kicker magnet.
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

- - R I =26 0

I

0

~
CI)

0{)

.--R2 = 220

0.025--R2=2300!--R2=24 Q~

I.!§ -0.025--R2 = 250

>

-0.05

--500

Time (ns)terminated(b) R2 is changed
Fig. 2. Low-voltage pulse and reflection. (a) Rl is changed,(b) R2 is changed.

253

one is kept constant.
The reflected pulse is delayed by approximately
160 ns with respect to the initial signal because weobserve both of them on the same oscilloscope. Figure 2 shows that the characteristic impedance of the
kicker magnet is 23 n.
The voltage pulses at the electrodes of each cell are
shown in Fig. 3.
The measurement shows that the transmission timeof the kicker magnet is 59 ns and the field risetime is 69 ns. The calculated results of the inductance Lo and capacitance Co of the unit cell are obtained by Eqs. (1) and (2) as Lo = 0.14 J.LH, Co =136 pF. The calculated value of the inductance is almost the same as the designed value, but the calculated value of the capacitance is larger than the design value. The reason why the capacitance of theunit cell is larger than the design value is that thereis floating capacitance between the electrodes and the
housing.
We designed, produced and tested the PFN-type
kicker magnet. We determined that the characteristic
impedance of the kicker magnet is 23 n, the transmission time of the kicker magnet is 59 ns and the field rise

254

0.2
--- 0.0
:>
"--'
Il)

OJ)

....
~

-0.2

"0

:> -0.4-0.6Time (ns)Fig. 3. Voltage pulse at the electrode of each cell.

time is 69 ns. The measurements demonstrate that thedesign of the kicker magnet for BSR is quite realistic.
We intend to perform further tests and study the kickstrength and the amplitude stability.
References
1) T . Ohkawa et al.: Proc. 17th PAC , Vancouver , 1997,
p. 1024 (1998).

RIKEN Accel. Prog. Rep. 33 (2000)

Development of a High-Intensity Slow-Positron Source for
Cooling of Highly Charged Ions
N. Oshima, D. Dumitriu, T. M. Kojima, A. Mohri, H. Oyama, T. Kambara, Y. Kanai,
Y. Nakai, M. Wada, and Y. Yamazaki
We study positron cooling of highly charged ionsin an electromagnetic trap in which more than 108
positrons must be prepared. In order to stack sucha large number of positrons at a high accumulation
rate, a high-intensity slow-positron source is under development.
Slow positrons are generally produced by moderation of fast positrons which can be obtained by (3+decay of radioisotopes or pair production using an accelerator. Fast positrons injected into a moderator lose
their energy via inelastic collisions and a considerable
fraction is ejected into vacuum as slow positrons. Theenergy spread of slow positrons is typically less than
3 eV, hence , slow positrons are controllable as a beam
by beam optics.
In our study, rare-gas-solid moderators such as thosemade from Ne, Ar, and Kr are used.
Rare-gassolids are well known to be efficient moderators of
positrons. 1) When the positron energy becomes lessthan the inelastic threshold of the moderator, thepositron energy loss is reduced drastically since phonon
excitation becomes the dominant process of the energy
loss. Threshold energies are relatively large in rare-gas
solids , therefore, positrons can diffuse long distances
about 1 /.Lm , and the reemission probability into vacuum increases.
Figure 1 shows a shcematic of the slow-positron

positron source

source. An encapsulated 22N a positron source ismounted on the top of a refrigerator and is cooled down
to 5 K, so that a rare-gas-solid moderator is formed on
its front face (see, Fig. 2). Slow positrons are thenextracted using an electrostatic field and guided magnetically to an electromagnetic trap.
The trap is set in a superconducting magnet which
generates a strong magnetic-field, BT = 5 T, to achievea stable confinement of positrons. When positrons are
injected into a strong magnetic field, they are subject
to a repulsive force. This is called the magnetic mirror
effect. Under the assumption that positrons are guided
adiabatically into the trap, the positrons must have akinetic energy of greater more than a threshold energy
Ea to overcome the magnetic mirror effect. Ea is calculated as Ea = E..l.BT/B o, where Bo is the magnetic-

refrigerator 5K

NAI insulator
positron source

Na-2250mCi

refrigerator

slowe+

extraction &ground grid
thermal shield

20K
Fig. 2. Positron source and moderator assembly.

s

Table 1. Expected specifications of the positron source.

Fig. 1. Design of a slow-positron source.

positron source
beam intensity
beam energy
energy spreadbeam diameter
magntic field strength
at a moderator

22Na (50 mCi)
10 7 positrons/sec
0-500 eV
2 eV
5 mm
0-0.25 T255

field strength at the moderator and E..L (= 2 eV) is
the positron kinetic energy component perpendicular
to the magnetic field at the moderator. We designed
coils around the moderator which can form a magnetic
field of up to Bo = 0.25 T ; hence, Ea is expected to be
only 40 eV . Consequently, almost of all of the generated slow positrons can be injected into the trap at anenergy of more than 40 e V.
The expected specifications of the new slow-positron256

source are listed in Table 1. The high-intensity slowpositron source will be used not only for a positroncooling study but also for other experiments, such as
positron-ion collisions and a positronium beam production, and simulations of antihydrogen formation
techniques.
References
1) R. G. Greves et al.: Can. J . Phys. 74, 445 (1996).

RIKEN Accel. Prog. Rep. 33 (2000)

Preliminary Studies on CORBA-based RIBF Control System
T. Tanabe, T. Masuoka, and M. Kase
The common object request broker architecture(CORBA)l) provides a means of communication between applications regardless of their physical location
or design. The object request broker (ORB) allows
client objects to invoke methods in a server object
without having to know specific information about themachine the server is running on, its programming language, or where it is located. The ORB intercepts
method calls and attempts to find an object which canperform the request . The Internet inter-ORB protocol (IIOP), which is used for communication among
ORBs, is expected to become one of the next standard
communication protocols for the internet.
CORBA would prevent us from becoming vendor dependent because it allows different operating systems(OSes) and platforms to communicate with each other.
It would also make integration of legacy controls easier, which is suited for the RIBF project as it is an
expansion of existing facilities. There are several accelerators and telescopes currently in operation aroundthe world whose controls are based onCORBA. However , the use of ORBs on real-time operating systems(RTOSes) in VME is just starting and very few examples exist. Therefore, as a part of the R&D work for
the RIKEN RIBF control system, we have conductedvarious tests of ORBs for RTOSes on VME/CPCI.
The main purposes of our R&D are:(1) To establish CORBA-based communications
among different CUls (created in C++ and Java) andVME/CPCI running different RTOSes.
(2) To estimate the total operational overhead dueto the use of CORBA.
(3) To confirm interoperability through IIOP among
different ORBs.
(4) To clarify the deficiencies, if any.
In addition to the interoperability test, the ORB
chosen for use in all components was VisiBroker 2 )due to the availability of both VxWorks 3 ) andpSOSystem 4 ) as well as its widespead use throughout the Netscape browser. Visual C++ 6.0 is used
for C/C++ applications and Visual Cafe for Enterprise
Edition 5 ) is used for Java applications. Figure 1 shows
the system configuration for this R&D.
A few CUI applications are written using C++ which
utilizes conventional socket functions to communicate
with VxWorks running on a PowerPC 604 based VME(Motorola MVME 2600). We have installed and tested
the function of a variety of VME I/O boards with a
VxWorks driver. Then, sources for each layer weremodified and compiled with links to CORBA libraries.
Using CORBA, one can discard routines for socket
functions which require detailed information on the

CPU ,Pentium II )(eon .!5OIoIHz

I~ c

CORBA Server (WS)
Solarls2.6
Various ORBs,-,,<tPCIOIO t l ' l ! .

~~:!~=loa
Memory:faMlt
pSOS:Uva.leroMr :11.2.' (e...1

S. i tdlBox

tl'l!NJIlAOIO't1E.

cptJ :Motcwoa. MVMueoo
PowerttClO4t33MHt='~.

L -_ _ _ _ _ _----'~3.2.1.2(c..)

Fig. 1. CORBA test system configuration.

hardware characteristics of both sending and receivingsides. The client, who may not know the details of theserver, simply invokes the server object to complete a
two-way communication.
Under normal circumstances for accelerator controls,
the interface information is known and static. Therefore, static invocation interface (SII) is adequate. Dynamic invocation interface (DII) can be used when thetypes of parameters used in the programs are unknown.
The program of the client using DII will be more complex because operations, such as looking up the argument of the server and returning the value must be
carried out dynamically. As far as RIBF controls areconcerned, DII is deemed unnecessary. A naming service (NS) is useful in the case one type of ORB is used
for the entire system.
For comparison, the response times for various I/Oboards have been measured for three different methods. Test routines include the following: (a) Server returns I/O values at the request of a client. (b) Client
invokes the object 100 times and the elapsed time ismeasured. This routine is repeated 10 times to obtain
more reliable statistics.
In addition to VisiBroker, a free ORB (for noncommercial use only) such as ORBacus,6) was used toevaluate the interoperability among different ORBs.
The interoperable naming service is not available until
CORBA 3.01) so one way to pass the object reference
across different ORBs is as follows: (1) Interoperable
object reference (lOR) is changed into a string, and aserver side writes it to the file. (2) A client side reads
the file created on the server side, and returns a string
to lOR. A file is delivered with FTP, NFS, and so on.
The times for two-way calls for different configurations
have been measured and compared. The method is asfollows: (a) Server returns a random number (float)257

when it is called upon by a client. (b) Client invokes
the object 10000 times and the elapsed time is measured. This routine is repeated 10 times to obtain morereliable statistics.
One of our goals is to establish a heterogeneousenvironment for the accelerator controls. Therefore,a RTOS other than VxWorks should be tested. A
pSOSystem has been chosen due to the availability ofORBs, particularly VisiBroker. A compact PCI CPU
board (AVAL DATA ACP-100)7) is used as the main
controller. A DIO board by the same manufacturer 8 )is installed for comparison as a corresponding VME
board. However, numerous unforeseen problems prevented us from completing this test in time for publication.
For the measurement of response times for various
I/O boards, Windows-NT 4.0 is used as the client OS
and Visual C++ 6.0 is used as the compiler. For th~server, VxWorks 5.3.1 running on PowerPC 604 andits C++ compiler are employed. VisiBroker is used forboth the client and server. Table 1 lists the measurement times in msec for different methods. It seems
that the rather large fluctuation in the response forsocket communication is due to the use of an eventdriven socket library (CAsynchSocket). Events not related to this test might have ffected the results duringtransmission. As for the DII cases, this particular test
somewhat sacrifices the generality. The server interface definition languages (IDLs) are given a priori sothat the time during which the DII searches for theinterfaces is shortened .
The results of interoperations among different ORBs
and OSes are listed in Table 2. The numbers withan asterisk indicate that a VisiBroker function utilizing interprocess communication is used. So far, only
ORBacus for Java has been tested for Java/CORBA
implementation. JDK 1.2 has been used for the evaluation. It suggests that Java client implementation
for this particular ORB is approximately 2.5-3.5 times
slower than C++ implementation for the same task. It
is yet not certain whether variations in response among
different. OSes are due to those in hardware performance or in software design. It appears that VxWorks
as a server gives smaller fluctuations in response thanother OSes as expected for RTOS.
For comparison, the times using socket programmingare shown in Table 3. Instead of the event driven socket
library (CAsyncSocket) , winsock.dll is used to measure
Table 1. Response Times for Various I/O Boards [msec].
SIl

DI
AI
DO

AO :.:

258

Drr (Sv. idls knownNS

Smart A£e nl
SmanA enl & NS
Av,
Av.
SId. Dev.
Std. Dev.

SmartA2enl & lR
Av.
Sid. Dev.

1.25
1.41
1.29
1.27

1.25
1.25
1.27
1.28

0
0
0.09
0.05

1.12
1.24
1.19
1.22

0.07
0.05
0.08
0.07

0.00
0.00
0.05
0.07

SocketCAsyncSocket
Av.

SId.Dev.

1.00
1.68
3.44
1.89

0.91
0.34
1.61
0.28

Table 2. Response time matrix for various ORBs and OSes(average [std. dev.] in I-tsec). Asterisked numbers using
IPC are 446 and 177 I-tsec, respectively.
SUD
NT
~
nt.
519*[0.0819] 428 [0.191];j:~;;:'.. ORB,

VisiBroker (c++)(;Ii ..

VisiBroker Sun
(C++)

NT

ORBacu&~?:,:: Sun(C;+) I"i,,/.:: NTSun
ORBacusNT(Java)

VxWorksSun, ':' '~ '~~J;:(~NT

735 [0.0481] 380 [0.0525] 455 [0.178]
492 [0.191) 317*(0.00876] 664 [0.0154] 413 [0.0838) 321 (0.0115]
768 [0.0467] 351 (0.158] 460 [0.422]
466 [0.103] 417 (0.269]
497 [0.0886] 327 [0.0158] 727[0.00422] 406 [0.179] 328 [0.00738]
1340 [0.129] 1237 [0.102] 1635[0.0706) 1243 [0.0953) 1256 [0.0644]

Table 3. Response time for socket communication [l-tsec].

~

ClientSocket · Sun
,

..

NT

,,',:

, ':,7
Socket ,:" ,',::
VxWorksSunNT
110 [0.0242 180 [0.0389] 185 [0.0094]
180 [0.0283 121 [0.0135] 165 [0.0080]

VxWorks

genuine elapsed time for socket communication.
It is now preferable to create GUls for OPI in Javabecause of its portability among different platforms.
Sharing codes with other laboratories is one of themost important benefits of using Java/CORBA. Visual Cafe has been tested to create GUls using Javabeans 9 } component. We also plan to test more Java implementation of ORBs both as a client and a server toaugment the matrix for interoperation. An object oriented database management system (OODBMS) may
replace the relational database management system(RDBMS) for CORBA-based accelerator controls. Objectivity/DB for Linux 10 ) is being tested for future application.
It has been shown that replacing socket communication with a CORBA layer significantly improves the
manageability of accelerator controls. There appears
to be no significant problem associated with VisiBroker on VxWorks. For the pSOS version, there appear
to be more problems, but these may also be due to ourlack of experience on this OS. Interoperability between
ORBacus and VisiBroker is found to be satisfactoryand response times do not vary greatly with different combinations. Without using product dependent
CORBA services, the flexibility of the system codes
can be improved at the expense of finding ways to sharethe stringified objects.
References
1) http://www.omg.org/
2) http://www.borland.com/visibroker /3) http://www.windriver.com/products/html/vxworks.htm4) http://www.isi.com/
5) http://www.microsoft.com/
6) http://www.ooc.com/
7) http://www.avaldata.co.jp/jpn/index.html
8) http://elc.aska.or.jp/electro/index.html
9) http://www.javasoft.com/
10) http://www.objectivity.com/

RIKEN Accel. Prog. Rep. 33 (2000)

Spin Tracking with "Real" Siberian Snakes in Relativistic
Heavy Ion Collider(RHIC)
M. Xiao and T. Katayama
To achieve high-energy polarized proton collision in
Relativisic Heavy Ion Collider (RHIC), the polarized
protons should be accelerated to a high energy without losing their polarization, which requires an understanding of the evolution of spin during accelerationand the tools to control it. The spin of a polarized
proton in external magnetic fields is governed by theThomas-BMT equation!)

dB

e

~

~

~

di = -Cym )[(1 + G'Y)B.l + (1 + G)Blil x S,

(1)

where the polarization vector § is expressed in theframe that moves with the particle. jj.l and jj/ / arethe magnetic field components perpendicular and paralell to the velocity iJ of the particle, respectively. G
is the anomalous gyromagnetic g-factor, G = 1.7928
for the proton. 'Y = E / m, ,mc2 is the energy of themoving particle. The orbit motion of the particle isgovened by the Lorentz force equation as follows

diJe~dt = -('Ym) [B.l] x iJ.

(2)

From the comparison of these two equations it canreadily be seen that in a pure vertical field, the spinrotates G'Y times faster than the orbital motion. In
this case, the factor G'Y gives the number of full spin
precessions for every full revolution, and we define it
as spin tune, v sp'
The polarization of polarized protons can be destroyed at many energies during the acceleration in
RHIC , known as the depolarizing resonances with two
types, the intrinsic resonances and imperfection resonances. Intrinsic resonances arise from the spin motion
coupling with horizontal magnetic fields due to vertical betatron oscillations. Imperfection resonances arecaused by orbit distortions due to field errors. The
resonance conditions 2 ) are vsp = kP ± Vy for intrinsic
resonances and vsp = k for imperfection resonances.
Here, k is an integer and P is the superperiodicity of
the accelerator; P = 3 in RHIC. Vy is a vertical betatron tune; Vy = 29.18 for RHIC.
The Siberian Snake is a local spin rotator, which
is proposed to rotate the spin by 180 0 around a horizontal axis with no effect on the orbit motion of theparticle. Figure 1 shows the rotations of three components of the spin in the ring with two Siberian Snakes
installed. It was found that the kick of transverse magnetic field perturbations on spin can be cancelled every
two revolutions if the axes of the two Siberian Snakes
are perpendicular to each other. Therefore, with the
installation of two Siberian Snakes in each ring of the

Fig.!. Rotations of three components of the spin in thering with two Siberian Snakes.

RHIC, the spin tune becomes one-half and is independent of the beam energy. Clearly, the depolarizing resonance conditions cannot be satisfied anymore, and no
depolarization would occur .
The depolarization due to the resonances can bestudied by numerically tracking protons with spin.
The equations of spin motion are linear, and hence thetransformation of the spin variables can be describedby a matrix, whose elements depend only on the orbital quantities. The spin rotation matrices of someordinary magnets such as dipole, quadrupole and sextupole magnets were obtained. 3 ) Based on the numerical field map generated by TOSCA, the study of spin
precession and orbital motion in a Siberian Snake wascompleted. 4 ) The work gave the energy-dependent numerical symplectic orbital matrices and unitary spin
matrices of the snakes and the results were used inspin tracking with "real" Siberian Snakes in RHIC forthe entire acceleration and storage period.
The tracking code SPINKS) was upgraded for the
spin tracking with "real" snakes in RHIC. The general idea is to track one or a certain number of protons, located on the contour of a phase-space ellipse
or randomly generated inside a phase-space volume
with Gaussian distribution, through the machine lattice. Each proton is characterized by four normalized259

transverse canonical variables of phase space, (x,Px =Px/Ps,Y,Py = Py/Ps), the longitudinal one pair ofcanonical variables,( -c~t, Pt = ~E)
and three compoP.C
nents of a real unitary vector of spin, § = (sx, Sy, sz).
The quantities Px and Py are transverse momenta, and
Ps is the momentum of the particle. ~E = E - Eo,
where E and Eo are the total and design energies, respectively. 5s is defined as ~,and ~t is the relativePo
time respect to synchronous particle. We define f) as
the vertical coordinate for a horizontal ring.
Orbital tracking is carried out using symplectified
first-order "transport" maps provided directly by the
optical code MAD.6) To study the problems of lattice misalignments and field errors, MAD transmits to
SPINK on the errors (measured or randomly assumed)of each machine element and corrected closed orbit distortion. SPINK accordingly displaces and rotates thecorresponding orbit transport maps.
The numerical matrices of two types of Siberian
Snakes in RHIC are inserted into the lattice as follows

r-r-

(a)

'fj

'~

(b)

1

"rr

1.0
0.0
.1.0
1.0
0.0
·1.0
1.0

ii'

0 .0
·1.0
1.0

·1.0
100

200

300

400

500

Gy

Fig. 2. Spin tracking with Real Snakes in RHIC, ideal
machine (a) 5 1Tmm·mrad, (b) 10 1Tmm·mrad, (c)15 1Tmm·mrad, and (d) 20 1Tmm·mrad.

'r rCa)

1-

260

(d)

0 .0

(3)
where M represents both MT and Ms. MT is a 6D symplectic orbital map of the snakes, and DL/2 isthe drift matrix of the half length of the snake. Sinceboth orbital maps and spin matrices of the snakes areenergy-dependent, their interpolation is necessary ata certain energy during the acceleration of the polarized proton. Special care has been taken to keep
the interpolated orbital map symplectic and the spin
matrix unitary. The spin tracking with real Siberian
Snakes in RHIC has been completed through the acceleration from the injection energy 25 GeV to the
top energy 250 GeV. The momentum gain per turnis 3 x 10- 5 Ge V /C. Figure 2 gives the single particle tracking results in RHIC with no misalignment in
the lattice. The particle is extracted from the contourof phase space, with an emittance of 5 7rmm·mrad,
10 7rmm·mrad, 15 7rmm·mrad and 20 7rmm·mrad,
shown in (a )-( d) respectively. The depolarizations of
the spin in this figure are only caused by intrinsic resonance. Figure 3 indicates the single particle tracking
results in RHIC with the misalignments asigned randomly by a truncated Gaussian distribution, the r.m.S
value of 2.5 mm and the stardard deviations of 1 mm
for the position in x and y directions and 1 mrad forthe rotation angle around the s-direction. The corrected closed orbit distortion is 0.2 mm (r.m.s.). The
depolarizations of the spin in this figure are caused byboth intrinsic and imperfection resonances.
It has been shown that (1) "real" Siberian Snakes
can maintain the polarization of the protons throughthe acceleration of more than 95% in a RHIC machinewith no closed orbit distortion, and of more than 88%
in a machine with corrected closed orbit distortion of
0.2 mm (r.m.s) if the polarized proton is extracted froma contour of less than 10 7rmm·mrad. (2) symplec-

(e)

'rr

-1

~~f

H'

(b)

-1

....,.

11'

"I~("

11"

IT~~"'"

-1

(dl

-1

100

200

Gy

300

400

500

Fig. 3. Spin tracking with Real Snakes in RHIC, misalignment randomly assigned, COD ~ 0.2 mm (a)5 1Tmm·mrad, (b) 10 1Tmm·mrad, (c) 15 1Tmm·mrad,and(d) 20 1Tmm·mrad

tic problems on orbital motion are one of the key issues for the spin tracking for over 10 7 turns. We solve
this problem, and make it possible to predict the "actual" operation conditions in RHIC with real Siberian
Snakes.
References
1) V. Bargmann et al.: Phys. Rev. Lett. 2, 15 (1959).
2) S. Y. Lee: AlP Conf. Proc., No. 223, p. 30 (1990).
3) T. Katayama: Basic Theory of Spin Dynamics in RHIC,
1996.
4) M. Xiao: Spin note AGS/RHIC/SN, No. 078, BNL Internal Paper, Sept. 10 (1998).
5) A. Luccio: Spin note AGS/RHIC/SN, No. 011, BNLInternal Paper, Sept. 14 (1995).
6) F. Christoph: The MAD Program Version 8.13 Physical
Method Manual., Geneva, Jan., 1994.

RIKEN Accel. Prog. Rep. 33 (2000)

Ion Optics Study of RHIC OPPIS
T. Takeuchi, M. Okamura, and A. Zelenski*
A new optically pumped polarized ion source(OPPIS)l) has been developed for the relativistic
heavy-ion collider (RHIC) which is now under construction at Brookhaven National Laboratory (BNL),New York, United States of America. In order toachieve a luminosity of 2 x 10 32 /s cm 2 in RtIIC, the
new source is designed to deliver polarized protons of
1.S mA and 200 J-lS with a polarization of more than
8S%. We have studied the beam optics and depolarization effect of this beam extraction system at this highcurrent.
A schematic view of the OPPIS is shown in Fig. 1.
The protons pick up a polarized electron in the Rb cellto become neutral. The neutralized H beam drifts,
without being affected from the magnetic fields tothe sodium cell, where it picks up an electron to become H-. The H- beam then leaves the OPPIS under the influence of the fringing field of the ionizer
solenoid. The beam emittance and the polarization
are determined at the ionizer solenoid, which consistsof a solenoid magnet and a sodium jet cell.
To investigate the effect of multiple charge exchange
processes and the degradation of a longitudinal spinpolarization caused by a fringing field of the solenoidal
magnet, the optics and the polarization of the particles were tracked by a combination of the Runge K utta
method and the Monte Carlo method. A magnetic fieldmap (Br,Bz) in the Runge Kutta simulation was obtained by OPERA-2D and the Monte Carlo method forthe charge exchange processes. Further details on the
numerical simulation have already been published. 2 )In this simulation, SOOO particles of HO atoms, weretracked from 20 cm upstream of the center of thesodium cell ([20 cm] x¢[2.0 cm]), to 30 cm downstreamof it. The assumed incident HO beam was almost parallel, the phase ellipse of which was (±10 mm: circle) x (±1 mrad). We assumed H°--+H- and H- --+Hoas charge exchange processes (CEP) between hydro-

I><J
HO__

~

__

I_- ____________ ~~-----~I---~

ECR Cavity

Rb Cell

Sona Field

H+

~_+_.

Superconducting Solenoid
2.ST

~

H-

~

Na Cell

Ionizer Solenoid
1.4 kGauss•Area of Calculation•
Fig. 1. Schematic view of RHIC OPPIS.

gen and sodium atoms, with cross sections of about
0.03 x 10- 14 cm 2 and 0.30 x 10- 14 cm 2 , respectively,
which are obtained from Ref. 3, respectively. At thebeam energy of 3.S keY from the ECR ion source,other cross sections for CEP are some orders of magnitude smaller than the cross sections of the processes
mentioned above and are negligible for this calculation. The sodium vapor distribution was assumed to
be Gaussian and the total vapor thickness was set to
be 10 15 atoms/cm 2 . In the spin calculation, it was assumed that the nuclear spin of incident HO atoms has
100% polarization. 4 ,5)Figure 2 shows the calculated results of the beam
trajectory. The point Z = 0 is the center of the sodium
vapor cell (length = 20.0 cm). In Fig. 2(a), the thickand thin solid lines indicate the magnetic field distribution and the sodium vapor density distribution
with (J = 3.0 cm, respectively. Figure 2(b) and (c)shows the HO and H- trajectories of the transverse X
projection, respectively, where only 100 particles areshown. It is clearly seen that the H- ions diverge fromthe Z axis due to the existence of the fringing field

'"'E
~
8

~~

-s
O'

Hz :::: ~
0

-0.2

0.04

.s--.:><: -0.02
0
0.02

-0.1

0

0.1

0.1

~------

0.2

0.3

0.2

:
0.3

I

I

0.2

0.3

'P:5~

0.05 ~

oi

e-

0.4

i

lIiilll~!

I(c) If ~ . . -.
••
_
.
I
I
-O·~O·<-:::.2"'-"-~--}-O.-:-"1--'--'~o!:-'-"""--'--'-O;::"-~l:;-'--'~~-'-'-~;;-'::-'~~
0.3
0.4
0.2

1

Z(m)

Fig. 2. The beam trajectory and charge exchange points
in the case of the sodium vapor density distribution of(J = 3.0 cm. The point, Z = 0, corresponds to the center of the sodium jet cell (length = 20 em). In (a), thethick and thin lines indicate the magnetic field distribution and the sodium density distribution, respectively;(b) and (c) show HO and H- trajectories of the transverse X projection, respectively, where 100 particles aretraced. In (d) , the charge exchange points of H°--+Hand H- --+Ho are plotted.

TRIUMF , Canada

261

0.3
0.98

0.4
0.14
0.12
0.1

0.96

~
0.94
0.92
0.3

t::I:I~

0.08~
0.06,g
0.04
0.02
0
0.4

Z(m)

Fig. 3. Motion of the longitudinal spin polarization. The
thick line indicates the field strength along the beamaxis. Thin lines indicate the longitudinal spin polarizations.

emanating from the solenoid magnet. On the other
hand, many of the HO atoms pass straight through thesodium jet ionizer cell. The points where the charge
exchange of H°-+H- or H- -+Ho occurs are plotted inFig. 2(d). The H- ion production yield was estimated262

to be 9.0%. The beam radius and the normalized beamemittance for the H- ion are about 13 mm and 2.4
7r mm mrad, respectively. Figure 3 shows the degradation of the nuclear spin polarization. The nuclear spinpolarization is 94-100% at 30 cm downstream of thesodium ionizer cell. S } .
Based on the results of the simulation describedabove, the beam extraction system and the low energy
transport line were optimized and are being fabricatedat BNL.
References
1)
2)
3)
4)

A. N. Zelenski et al.: Proc. PAC99 , New York.
T . Takeuchi et al.: Rev. Sci. Instrum. 69 , 412 (1998).
M. Tanaka et al.: Phys. Rev. A 50, 1184 (1994).
T. Takeuchi et al.: Spin Note AGS/RHIC/SN, No. 077,
BNL Internal Paper, Sept. 10 (1988).
5) T. Takeuchi et al.: Proc. Int. Workshop on Polarized Sources and Targets (PST99) , Erlangen, Germany,
1999, to be published.

RIKEN Accel. Prog. Rep . 33 (2000)

Ultraslow Muon Production Using the Resonant Ionization Method
Y. Matsuda, Y. Miyake, K. Shimomura, P. Bakule, R. Scheuermann, P. Strasser,
S. N. Nakamura, N. Kawamura, K. Ishida, T. Matsuzaki, and K. Nagamine
Muons have been used in numerous research fields ,such as muon-catalyzed fusion, material sciences, andfundamental physics. In particular, the use of polarized muons as spin probes in matter (I-LSR method) has
been used by many researchers, and it is widely recognized that the I-LSR method provides a unique tool forstudying various aspects of matter.
The muon beam for I-LSR is delivered from an accelerator facility, such as ISIS, where the RIKEN-RAL
muon facility operates. Certain characteristics of themuon beam, however, may limit its application. For
example, the energy of the produced muons is in the
Me V range and their energy spread is approximately
10%. In practice, this limits the application of the I-LSR
method to the study of characteristics of bulk matter
only. In order to study surface characteristics or different implantation depths in a material, it is essential touse a polarized muon beam with variable energy froma few eV to a few tens of keY, with small energy distribution. The realization of such a muon beam will
open new possibilities for I-LSR studies.
An apparatus for production of ultraslow muons isunder construction now at the RIKEN-RAL muon facility.
A muon beam with an energy of approximately
4 Me V is injected into a thin tungsten foil which isheated up to about 2000 K. Muonium atoms withthermal kinetic energy are evaporated from the surface after its formation following electron-capture in
the foil. l ) Then, the electrons of the muonium atoms
are removed by irradiation with VUV laser light toproduce ultraslow muons (Fig. 1) .

muomummuon beamtungs ten film
laser light
Fig. 1. Schematic diagram of the resonant ionization
method to produce ultraslow muons.

This resonant ionization method has been developed at the Meson Science Laboratory of High Energy
Accelerator Research Organization (KEK). 2) Anothermethod using cryogenic moderators has been developed at the Paul Scherrer Institute (PSI)3) and is also
used on the RAL EC site (DEVA area). Using thecryogenic moderator method at a pulsed muon facility,
the time resolution for I-LSR experiments is determinedby the pulse width of the primary muon beam, which
is approximately 100 ns (or 450 ns at higher intensities). The laser resonant ionization method offers amuch better time resolution since the time structureis determined by the temporal width of the VUV laser
pulse, which is approximately 5 ns. That is, by using the resonance ionization method, we can also overcome the current limitation of time resolution of pulsed
muon beams.
The experimental apparatus mainly consists of twoparts. One is the laser system for generation of the
VUV laser light to ionize muonium in the region of
the hot tungsten target. The second part is the beamtransport system, in which the ultraslow muons are
extracted and delivered to the sample region.
We ionize muonium through the 1S~2P~unboundtransitions. The energy difference between IS and 2P
states is 122.05 nm in the case of muonium atom. To
obtain the required 122 nm photon, we adopt the sumdifference frequency mixing method, using two photons of 212.55 nm for two-photon excitation of the4P 5 5P[1/2, OJ state in krypton, subtracted by a photonof a tunable difference wavelength. 4)
To generate 212.55 nm light, we first obtain singlemode 850 nm light with an OPO(Optical Parametric
Oscillator) system. Then, the 850 nm light is amplified by a Ti:Sapphire crystal which is pumped byfrequency-doubled Nd:YAG laser light. The output
energy of the amplifier is approximately 230 mJ /pulse
with a 25 Hz repetition rate. This beam is split
into two light paths. By using Ba2B04 crystals forfrequency-quadrupling, two beams, each with a wavelength of 212.55 nm and an energy of 6 mJ /pulse, aregenerated.
The difference wavelength is generated by a system
consisting of OPO and OPA(Optical Parametric Amplifier) crystals which is driven by a frequency-doubled
Nd:YAG laser. We obtain 25 mJ /pulse at a wavelengthof 820 nm and with a 25 Hz repetition rate.
Another 355 nm of photons from a frequency-tripled
Nd:YAG laser are used to remove electron throughtransition from the 2P state to an unbound state. This
scheme is illustrated in Fig. 2.

263

OPO &
T i:S al} l}h ire

pre-amp.

OPO &
OPA

e

Fig. 2. Diagram of the laser system which is used in the resonant ionization method to
obtain 122 nm photons and 355 nm photons for ionizing muonium atoms.

]
Laser Cabin

J

2m 4m
I

I

Fig. 3. Layout of the RIKEN-RAL muon facility and the laser cabin constructed for theultraslow muon generation experiment. The temperature in the cabin is stabilized
within 1 K .

The ultraslow muons generated at the production
region are accelerated up to 10 keY, and then transported to a microchannel plate (MCP) detector locatedat the end of the transport system. The muons are
identified by their charge( Q) / mass ratio which was selected by adj usting the magnetic field of a bending
magnet in the transport system, and by their time-offlight (TOF) spectrum.
The construction of the apparatus is now underway. The laser cabin was constructed next to thePort 3 experimental area at the RIKEN-RAL muon facility (Fig. 3). Installation of the laser system is now in

264

progress. The beam transport system is currently being tested in Japan. The installation of the optics will
be carried out in spring of year 2000, and we aim tostart the experiment in June 2000.
References
1) A. P. Mills et al.: Phys . Rev. Lett. 56, 1463 (1986).
2) K. Nagamine et al.: Phys. Rev. Lett. 74, 4811 (1995).
3) E. Morenzoni et al.: Hyperfine Interact. 106, 229(1997) .
4) J. P. Marangos et al.: J. Opt. Soc. Am. B 7,1254 (1990).

VI.

RADIATION MONITORINGRIKEN Accel. Prog. Rep. 33 (2000)

Radiation Safety Control System for the RIKEN Ring Cyclotron
S. Fujita, S. Nakajima, S. Ito, H. Sakamoto,·1 A. Fujiwara,·2 A. Uchiyama,·2
M. Kase, and Y. Uwamino
The radiation safety control system 1) was in operation from 1986 until the first of February 1999.
This system, based on a minicomputer MITSUBISHI
MX-3000, is now out-of-date and trivial troubles,such as data transfer errors through an optical fiber,
often occurred. We replaced the old system with a new

network system when the Ring and AVF cyclotrons
were shut down for the relocation of the electric powersource. The new system consists of five different subsystems;(1) Radiation ·monitoring system(2) Access control system

The Radiation Safety Control System
Network
SystemRadiation Monitoring System
Enviromental Area Monitors
Inside Area Monitors
Room Air Monitors
Ventilation Monitor
Drain Monitors

Access Control System
Touch Panel for Entry
Gate
Operation Status Lamp
Radiation Level Indicator
Hand-Foot-Clothes Mon itor
Key BoxWorkstation

Central Surveillance System
Data Acquisition Equipment
Web Server
Beam Application system
Beam Application Equipment
Beam Shutter
Rotary ShutterInterlock Control System
Gate Status
Key Box Data Status
Radiation Level Status
Shie ld Door Status
Hand-Foot-Clothes Status
Ventilation Damper Status
Alarm Lamp Statu~

Fig.!. A block diagram of the new radiation safety control system .

(3) Beam application system(4) Inter lock control system(5) Central surveillance system.
The subsystems, based on a personal computer
and/or UNIX server, are interconnected via a network
system. A block diagram of this connection is shownin Fig. 1. The radiation monitoring system observes
the status of the radiation monitors and collects thedata from them. The collected data can be shown as
numerical values or on a graph. These data are transmitted to the central surveillance system through the
network, edited and stored on data acquisition equipment.
Several functions have been added to the new system. One of them is the display of names of people
staying in the safety controlled room on the monitor
screen set on the gate bar console, as is shown in Fig. 2.
The new system has been working continuously since
the middle of April 1999.
References
Fig. 2. Names of people in the safety controlled room aredisplayed on the screen on the gate bar console.

*1*21) 1. Sakamoto, S. Fujita, T . Wada, and H. Takebe:
RIKEN Accel. Prog. Rep. 20, 206 (1986).

Sumijyu Accelerator Service, Ltd .
Faculty of Science, Science University of Tokyo

265

RIKEN Accel. Prog. Rep. 33 (2000)

Routine Work for Radiation Safety in the Ring Cyclotron Facility
S. Fujita, S. Nakajima, S. Ito, H. Sakamoto,*l A. Fujiwara,*2 A. Uchiyama,*2 M. Kase, and Y. Uwamino
Measurement of Residual Radioactivity
Residual radioactivities in the ring cyclotron facility
were measured on the surface at various locations using
ionization-chamber survey meters. The measurements
were performed during the routine overhaul period aswell as after almost every beam experiment.
An experiment was carried out with a 59Co beamof 80 MeV/nucleon in the E6 experimental vault from
July 31 to Aug. 3, 1999, as the last beam experimentof the spring term. The routine overhaul started justafter that date. The dose rates in the ring cyclotron
and in the AVF cyclotron were measured from Aug. 9
to 31. The results are shown in Figs. 1 and 2 alongwith the date of measurement.
In the period from Oct. 1, 1998 to Sept. 30, 1999,
dose rates were measured along the beam lines. The
spots a-z, marked by bullets in Fig. 3, are theplaces where the dose rates exceeded 50 jlSv /h. Table 1 summarizes the observed dose rates and gives
the dates when the measurements were performed.
The maximum dose rate was found to be 17 mSv /h(1 7000 jlSV /h) at the target chamber, denoted by x in
Fig. 3. Whenever we observed a high dose rate, We
roped off the area and posted a sign warning that it
was dangerous to remain for long a time in that place.

DOSE UNIT: J.lSv/h
Beam

Fig. 2. Dose rates measured inside the injector AVF cyclotron. They are given in units of j..LSV Ih. The measurements were done on *1, Aug. 9 and *2, Aug. 11(1999) .
Table 1. Summary of the dose rates measured along thebeam lines with ionization-chamber survey meters. The
detection points a-z indicate the measured locations
shown in Fig. 3.
Detection Measured
point dose rate
(p.Sv/h)
a

b
c

d
e
f
g
h
j
k

i
In

n
0

DOSE UNIT: ~Sv / h
Beam~Fig. 1. Measured locations around the RIKEN Ring Cyclotron: EDC, electrostatic deflection channel; MDCl,
magnetic deflection channel 1; MDC2, magnetic deflection channel 2; MDPl, main differential probe 1;
MDP2, main differential probe 2; and MDP3, main differential probe 3. The numbers are dose rates in unitsof j.LSV Ih. The measurements were carried out on *1,
Aug. 26 and *2, Aug. 31 (1999).
*1 Sumijyu Accelerator Service, Ltd.
*2 Faculty of Science, Science University of Tokyo

266

p
q
r

s
t
u

v
w
x
Y

z

100
110
75
240
650
85
140
80
280
150
1650
300
50
90
60
55
90
105
80
3500
1950
100
220
17000
450
1100

Date

Particle Energy Intensity Period(MeV /u) (enA) (days)Jui 9, '99 dJui 9, '99 dJui 9, '99 dApr 15, '99 Ni-58
Apr 15, '99 Ni-58
Apr 15, '99 Ni-58
Sept 24, '99 Ne-20
Nov 9, '98 Ar-40
Nov 13, '98 Xe-136
Jan 5, '99 Co-59
Apr 15, '99 Xe-136
Sept 24, '99 C-12
Jun 9, '99 C-13
Nov 27, '98 Ne-20
Nov 27, '98 Ne-20
Nov 13, '98 Kr-84
Nov 26, '98 Ne-20
Dec 1, '98 C-12
Jui 12, '99 N-14
Jui 12, '99 N-14
Dec 1, '98 C-12
Jun 17, '99 dJui 9, '99 dJun 17, '99 dJui 9, '99 dJun 21, '99 d

135
135
135
25
25
25
135
95
7.6
80
7.6
135
100
135
135
70
135
135
135
135
135
135
135
135
135
135

100
2
2
100
100
2
500
2
2
500
2
500
630
1
750
3
1000
3
250
8
4500
4
1200
2
3200
12
1600
1
1
1600
7.5 3
1
1600
2000
2
1500
2
2
1500
2000
2
250
3
2
100
250
3
2
100
250
3

Measurement of Leakage Radiation Level
Having analyzed the collected data of leakage neutrons, we found that the radiation levels in the controlled area were much less than the allowable dose
limit. Leakage of -y-rays and neutrons was below theFig. 3. Layout of the RIKEN Ring Cyclotron facility as of 1999 . Measured locations of residual radioactivities along the beam lines are shown by bullets a - z.

detection limit of the environmental monitors. We
evaluated the radiation level at the boundary of theaccelerator facility using the leakage recorded with themonitor which was installed in the computer room on
the ground floor just above a bending magnet which

guided the beams from the ring cyclotron vault to the
distribution corridor. As a result , we obtained a radiation level of about 3 pSv /year which was much lessthan the permissible dose limit (1 mSv/year).

267

268

VII. LIST OF PUBLICATIONS
1.

Accelerator
physics

development

andaccelerator

A. Goto, H. Okuno, T. Kawaguchi, T. Mitsumoto,T. Tominaka, S. Fujishima, J.-W. Kim, J. Ohnishi,
K. Ikegami, N. Sakamoto, S. Yokouchi, K. Sugii, T.
Wada, T. Morikawa, T. Kubo, and Y. Yano:. "TheK2500 superconducting ring cyclotron of RIKEN RI
Beam Factory: Overview and status", Proc. 15th
Int. Conf. on Cyclotrons and Their Applications
1998, Caen, France, 1998-06, edited by Eric Baronand Marcel Lieuvin, pp. 148-155 (1998).
S. Kohara, Y. Miyazawa, O. Kamigaito, T. Chiba,
E. Ikezawa, M. Kase, and A. Goto: "Model studyof a resonator for a fiat-top acceleration system in
the RIKEN AVF cyclotron", Proc. 15th Int. Conf.
on Cyclotrons and Their Applications 1998, Caen,
France, 1998-06, edited by Eric Baron and Marcel
Lieuvin, pp. 219-222 (1998).
H. Okuno, T. Tominaka, S. Fujishima, T. Mitsumoto,T. Kubo, T. Kawaguchi, J.-W. Kim, K. Ikegami, N.
Sakamoto, S. Yokouchi, T. Morikawa, Y. Tanaka, A.
Goto, and Y. Yano: "Design study of the injectionand extraction systems for the RIKEN Superconducting Ring Cyclotron", Proc. 1997 Particle Accelerator Conf. (PAC )97), Vancouver, Canada, 199705, edited by Mike Craddock, pp. 21-23 (1998).
S. Hasegawa, A. Fujiwara, H. Yano, T. Nishimura, S.
Sasaki, H. Ohashi, T. Iwai, K. Kobayashi, and H.
Shibata: "Design of electrostatic accelerators for thedevelopment of microparticle detectors in Japan",Adv. Space Res. 23, 119-122 (1999).
S. Bhattacharjee and H. Amemiya: "Characteristics
of a plasma produced by high power short pulse microwaves", Bull. Am. Phys. Soc. 44, 252- 253(1999).
S. Bhattacharjee and H. Amemiya: "Production of microwave plasma in a waveguide with a dimension below cutoff", J. Tech. Phys. 40,213- 216 (1999).
D. Toprek, A. Goto, and Y. Yano: "Beam orbit simulation in the central region of the RIKEN AVF Cyclotron", Nucl. Instrum. Methods Phys. Res. A
425, 409- 414 (1999).
A. Goto and Y. Yano: "Construction of the RIKENSuperconducting Ring Cyclotron" , Proc. 12th Symp.
on Accelerator Science and Technology, Wako, 199910, edited by Y. Yano, RIKEN, pp. 7-9 (1999).
T. Takeuchi, T. Katayama, T. Nakagawa, M.
Okamura, T. Hattori, K. Sasa, and S. Kondrashev:"Development of laser ion source at RIKEN", Proc.
12th Symp. on Accelerator Science and Technology,
Wako, 1999-10, edited by Y. Yano, RIKEN, pp. 203205 (1999).
O. Kamigaito, M. Kase, Y. Miyazawa, T. Chiba, M.
Hemmi, N. Sakamoto, S. Kohara, E. Ikezawa, A.

Goto, and Y. Yano: "Construction of the chargestate multiplier system for the RIKEN RI-beamfactory" , Proc. 12th Symp. on Accelerator Scienceand Technology, Wako, 1999-10, edited by Y. Yano,
RIKEN, pp. 233- 235 (1999).
S. Fujishima, H. Okuno, A. Goto, and Y. Yano: "Analysis of the injection and extraction systems for the
RIKEN Superconducting Ring Cyclotron", Proc.
12th Symp. on Accelerator Science and Technology,
Wako, 1999-10) edited by Y. Yano, RIKEN, pp. 435437 (1999).
J.-W. Kim, A. Goto, T. Mitsumoto, and Y. Yano:"Studies on single turn extraction for a superconducting cyclotron", Proc. 1999 Particle Accelerator
Conf., New York, USA, IEEE, pp. 2268-2270 (1999).
O. Kamigaito, M. Kase, Y. Miyazawa, T. Chiba, M.
Hemmi, S. Kohara, E . Ikezawa, A. Goto, and Y.
Yano: "Construction of the first unit of the chargestate multiplier system for the RIKEN RI beam factory", Proc. 24th Linear Accelerator Meet. in Japan,
Sapporo, 1999-07, pp. 146-148 (1999).
S. Bhattacharjee and H. Amemiya: "Production of microwave plasma in narrow cross sectional tubes: Effect of the shape of cross section" ,Rev. Sci. Instrum.
70, 3332-3337 (1999).
O. Kamigaito, A. Goto, Y. Miyazawa, T. Chiba, M.
Hemmi, M. Kase, S. Kohara, Y. K. Batygin, E.
Ikezawa, T. Nakagawa, and Y. Yano: "Constructionof a variable-frequency radio-frequency quadrupolelinac for the RIKEN heavy-ion linac", Rev. Sci. Instrum. 70, 4523-4531 (1999).
A. Goto: "A superconducting ring cyclotron for the
RIKEN RI Beam Factory" , Teion Kougaku 34, 376384 (1999).
S. Bhattacharjee and H. Amemiya: "Build up characteristics of a plasma produced by high power shortpulse microwaves", XXIV Int. Conf. on Phenomena
in Ionized Gases, Proc. Contributed Papers Vol. 1,
Warsaw, Poland, 1999-07, edited by P. Pisarczyk,
T. Pisarczyk, and J. Wolowski, Space Research Centre, Polish Academy of Sciences, Poland, pp. 133- 134(1999).
2.

Nuclear physics and nuclear instrumentation

I. Tanihata: "The new RIB project at RIKEN", Nucl.
Instrum. Methods Phys. Res. B 126, 224- 230(1997).
K. Varga, Y. Suzuki, K. Arai, and Y. Ogawa: "Microscopic description of light unstable nuclei with thestochastic variational method", Nuc!. Phys. A 616,
383c-391 c (1997).
I. Tanihata: "Planned storage ring facilities in Japanand in China", Nucl. Phys. A 626 , 531c-544c(1997).
269

N. Tanaka, Y. Suzuki, and K. Varga: "Exploration ofresonances by analytic continuation in the coupling
constant", Phys. Rev. C 56, 562-565 (1997) .
Y. Mochizuki and S. Kumagai: "The half-life of titanium 44 and SN 1987 A", The Hot Universe: Proc.
18-8 th Symp. of the Int. Astronomical Union, editedby K. Koyama, S. Kitamoto, and M. Ito, Kluwer
Academic Publishers, The Netherlands, pp. 241-242(1998).
Y. Mochizuki, T. Izuyama, 1. Tanihata, and K.
Oyamatsu: "A microscopic model of neutron starglitches", 1997 Pacific Rim Conf. on Stellar Astrophysics, ASP Conf. Ser., Vol. 138, pp. 245-248(1998) .
T. Uesaka, H. Sakai, H. Okamura, S. Ishida, N.
Sakamoto, H. Otsu, Y. Satou, T. Ohnishi, T.
Wakasa, T. Nonaka, G. Yokoyama, K_ Itoh, K.
"StudySekiguchi, T. Wakui, and Y. Yano:of deuteron high momentum component via the
3He(d~ p)4He reaction at 270 MeV", Int. Symp. on
New Facet of Spin Giant Resonances in Nuclei,
Tokyo, 1997-11, edited by H. Sakai, H. Okamura,and T. Wakasa, World Scientific, Tokyo, pp. 477479 (1998).
K. Yoneda, N. Aoi, H. Iwasaki, H. Sakurai, H. Ogawa,T. Nakamura, W. D. Schmidt-Ott, M. Schafer, M.
Notani, N. Fukuda, E. Ideguchi, T. Kishida, S. S.
Yamamoto, and M. Ishihara: "Half-life measurements of the neutron drip line nuclei 19B, 22C and
23N", J. Phys. G 24 , 1395-1398 (1998).
T . Suzuki, H_ Geissel, O. Bochkarev, L. Chulkov,
M. Golovkov, N_ Fukunishi, D. Hirata, H. Irnich,Z. Janas, H. Keller, T. Kobayashi, G. Kraus, G.
Miinzenberg, S. Neumaier, F. Nickel, A. Ozawa, A.
Piechaczeck, E. Roeckl, W. Schwab, K. Siimmerer,
K. Yoshida, and 1. Tanihata: "Nuclear radii of Na
and Mg isotopes", Nucl. Phys. A 630, 661-677(1998) .
L. Ya. Glozman, Z. Papp, W. Plessas, K. Varga, and
R. F. Wagenbrunn: "Light and strange baryons in achiral quark model with Goldstone-boson-exchangeinteractions", Nucl. Phys. A 631, 469c-472c (1998).
T. Uesaka, H. Sakai, H. Okamura, S. Ishida, N.
Sakamoto, H. Otsu, Y. Satou, T. Ohnishi, T .
Wakasa, T. Nonaka, G. Yokoyama, K. Itoh, K.
Sekiguchi, T. Wakui, Y. Yano, and M. Wakasugi:"Measurement of polarization correlation coefficientfor the 3He(d,p)4He reaction", Nuclear Study 43,
No.2, pp. 89-98 (1998).
K. Sumiyoshi and T. Ebisuzaki: "Performance of parallel solution of a block-tridiagonal linear system on
Fujitsu VPP500", Parallel Comput. 24 , 287-304(1998).
N. Dinh Dang, K. Tanabe, and A. Arima: "Dampingof hot giant dipole resonance due to complex configuration mixing", Phys. Lett. B 445, 1-7 (1998).
N. Dinh Dang, K. Tanabe, and A. Arima: "Contribu270

tion of higher-order processes to the damping of hot
giant dipole resonance", Phys. Rev. C 58, 33743387 (1998).
K. Varga, J. Usukura, and Y. Suzuki: "Second boundstate of the positronium molecule and biexcitons",
Phys. Rev. Lett. 80, 1876- 1879 (1998).
Y. Mochizuki, S. Kumagai, and 1. Tanihata: "The halflife of 44Ti and SN 1987 A", Proc. Int. Symp. on Origin of Matter and Evolution of Galaxies 97, edited
by Kubono et al., pp. 327-334 (1998).
Y. Mochizuki: "The origin of neutron star glitches",
Astron. Her. 92, 19-31 (1999).
Y. Mochizuki, T_ Izuyama, and 1. Tanihata: "Dynamics of exotic nuclear rod formation for the origin ofneutron star glitches", Astrophys. J. 521, 281-296(1999).
H. Miyasaka: "Observation of trapped anomalous cosmic rays with MIDORI satellite", Cosmic Radiation
1,117-125 (1999).
Yu. Ts. Oganessian, A. V. Yeremin, G. G. Gulbekian,S. L. Bogomolov, V. 1. Chepigin, B. N. Gikal, V.
A. Gorshkov, M_ G. Itkis, A. P. Kabachenko, V.
B. Kutner, A. Yu. Lavrentev, O. N. Malyshev, A.
G. Popeko, J. Rohac, R. N. Sagaidak, S. Hofmann,
G. Milnzenberg, M. Veselsky, S. Saro, N_ Iwasa, K.
Morita, and V. 1. Chepigin: "Search for new isotopesof element 112 by irradiation of 238U with 48Ca",
Eur. Phys. J. A 5, 63-68 (1999).
N. Dinh Dang, K. Tanabe, and A. Arima: "Temperature dependence of quantal and thermal dampings ofgiant dipole resonance due to complex configuration
mixing", Highlights of Modern Nuclear Structure, S.
Agata sui due Golfi, Italy, 1998-05, edited by A. Covello, World Scientific, Singapore, pp. 459-466 (1999).
K. Ishida, K. Nagamine, T. Matsuzaki, S. N.
Nakamura, N. Kawamura, S. Sakamoto, M. Iwasaki,
M. Tanase, M. Kato, K. Kurosawa, H. Sugai, 1.
Watanabe, K. Kudo, N. Takeda, and G. H. Eaton:"Measurement of X-rays from muon to alpha sticking and fusion neutrons in solid/liquid D-T mixturesof high tritium concentration", Hyperfine Interact.
118,203-208 (1999).
K. Sato, T. Miyake, A. Morishita, K. Matsuta, T.
Minamisono, M. Tanigaki, S. Takeda, M. Mihara,
M. Fukuda, Y. Nojiri, K. Minamisono, T. Fukao, Y.
Matsumoto, T. Ohtsubo, S_ Fukuda, S. Momota, K.
Yoshida, A. Ozawa, T. Kobayashi, 1. Tanihata, H.
Sagawa, H. Kitagawa, G. F. Krebs, J. R. Alonso, andT. J. M. Symons: "Hyperfine interactions of 19 0 in
Ti02 and quadrupole moments of 13, 19 0" , Hyperfine
Interact. 120/121,661-665 (1999).
K. Matsuta, T . Onishi, M. Fukuda, T. Minamisono,
H. Akai, M. Sasaki, T. Yamaguchi, T. Miyake, K.
Sato, K. Minamisono, F. Ohsumi, Y. Muramoto, S.
Oui, C. Ha, K. Tanaka, K. Kidera, A. Morishita, A.
Kitagawa, M. Torikoshi, M. Kanazawa, T. Nishio, S.
Koda, T. Ohtsubo, S. Fukuda, Y. Nojiri, S. Momota,
A. Ozawa, K. Yoshida, T. Suzuki, T. Kobayashi, 1.

Tanihata, S. S Hanna, J. R. Alonso, G. F. Krebs,
and T. J. M. Symons: "Electromagnetic momentsof short lived f3 emitters 21 F , 23Mg, 27Si and 39Ca",
Hyperfine Interact. 120/121,673- 677 (1999) .
E. J. Kim, T. Nakamura, Y. Uwamino, N. Nakanishi,
M. Imamura, N. Nakao, S. Shibata, and S. Tanaka:"Measurements of activation cross sections on spallation reactions for 59CO and natcu at incident neutronenergies of 40 to 120 MeV", J. Nucl. Sci. Technol.
36, 29-40 (1999).
T. Horibata, M. Oi, and N. Onishi: "Band crossing
studied by GCM with 3D-CHFB", J. Phys. G 25 ,885-888 (1999).
N. Nakao, Y. Uwamino , T. Nakamura, T. Shibata, N.
Nakanishi, M. Takada, E. Kim, and T. Kurosawa:"Development of a quasi-monoenergetic neutron fieldusing 7Li(p,nfBe reaction in the 70-210 MeV energy
range at RIKEN", Nucl. Instrum. Methods Phys.
Res. A 420 , 218-231 (1999).
T. Kurosawa, T. Nakamura, N. Nakao, T. Shibata,Y. Uwamino, and A. Fukumura: "Spectral measurements of neutrons, protons, deuterons and tritons
produced by 100 MeV/nucleon He bombardment",
Nucl. Instrum. Methods Phys. Res. A 430, 400422 (1999).
Y. Mizoi, T. Fukuda, Y. Matsuyama, T. Miyachi,
J. Nakano, N. Fukuda, M. Hirai, H. Kobinata,
Y. Watanabe, H. Sakurai, Y. Watanabe, and A.
Yoshida: "Multiple-sampling and tracking proportional chamber for nuclear reactions with low-energy
radioactive isotope beams", Nucl. Instrum. Methods Phys. Res. A 431, 112-122 (1999).
N. Dinh Dang, K. Tanabe, and A. Arima: "Shapeevolution of the hot giant dipole resonance", Nucl.
Phys. A 645, 536- 558 (1999).
T. Horibata, M. Oi, N. Onishi, and A. Ansari: "Bandstructures of 1820s studied by GCM based on 3DCHFB", Nucl. Phys. A 646, 277-295 (1999).
N. Dinh Dang, K. Tanabe, and A. Arima: "Quantal
and thermal damping of the hot giant dipole resonance due to complex configuration mixing" , Nucl.
Phys. A 649, 201c- 204c (1999).
1. Tanihata: "Reaction with radioactive ion beams" ,Nucl. Phys. A 654 , 235c-251c (1999).
A. Ansari, M. Oi, N. Onishi, and T. Horibata: "Highspin structure of 182, 184 0 s in tilted axis cranking approach", Nucl. Phys. A 654, 558- 578 (1999).
Y. Koike: "Twist-3 effects in polarized Drell-Van andsemi-inclusive DIS", Nucl. Phys. B (Proc. Supp!.)79, 626-628 (1999).
T. Kurosawa, N. Nakao, T. Nakamura, Y. Uwamino,
T. Shibata, N. Nakanishi, A. Fukumura, and K.
Murakami: "Measurements of secondary neutrons
produced from thick targets bombarded by highenergy helium and carbon ions", Nuc!. Sci. Eng.
132, 30- 57 (1999) .
H. Sakurai, S. M. Lukyanov, M. Notani , N. Aoi,
D. Beaumel, N. Fukuda, M. Hirai, E. Ideguchi,

N. Imai, M. Ishihara, H. Iwasaki, T. Kubo, K.
Kusaka, H. Kumagai, T. Nakamura, H. Ogawa, Y.
E. Penionzhkevich, T. Teranishi, Y. Watanabe, K.
Yoneda, and A. Yoshida: "Evidence for particle stability of 31 F and particle instability of 25N and 28 0" ,Phys. Lett. B 448 , 180-184 (1999).
M. H. Smedberg, T. Baumann, T. Aumann,
L. Axelsson, U. Bergmann, M. J. G. Borge,
D. Cortina-Gil, L. M. Fr aile , H. Geissel, L.
Grigorenko, M. Hellstrom, M. Ivanov, N. Iwasa,
R. Janik, B. Jonson, H. Lenske, K. Markenroth, G.
Miinzenberg, T. Nilsson, A. Richter, K. Riisager, C.
Scheidenberger, G. Schrieder, W. Schwab, H. Simon,
B. Sitar, P. Strmen, K. Siimmerer, M. Winkler, and
M. V. Zhukov: "New results on the halo structure of
8B", Phys. Lett. B 452, 1-7 (1999).
T. Suzuki and H. Sakai: "The Landau-Migdal parameters, g'NN and g'Nll", Phys. Lett. B 455, 25-29(1999).
K. Matsuta, K. Sato, M. Fukuda, M. Mihara, T.
Yamaguchi, M. Sasaki, T. Miyake, K. Minamisono,
T. Minamisono, M. Tanigaki, T. Ohtsubo, T. Onishi,
Y. Nojiri, S. Momota, S. Fukuda, K. Yoshida, A.
Ozawa, T. Kobayashi, 1. Tanihata, J. R. Alonso, G.
F. Krebs, T. J. M. Symons, H. Kitagawa, and H.
Sagawa: "Quadrupole moment of the proton dripline nuclide 13 0", Phys. Lett. B 459, 81- 85 (1999).
A. Ansari, M. Oi, N. Onishi, and T. Horibata: "HighK exotics in osmium isotopes", Phys. Lett. B 460,
24-30 (1999).
T. Uesaka, H. Sakai, H. Okamura, T. Ohnishi, Y.
Satou, S. Ishida, N. Sakamoto, H. Otsu, T. Wakasa,
K. Itoh, K. Sekiguchi, and T. Wakui: "Polarization
correlation coefficient for the 3He( d,p) 4 He reaction" ,Phys. Lett. B 467, 199-204 (1999).
J. Meng, K. Sugawara-Tanabe, S. Yamaji, and A.
Arima: "Pseudospin symmetry in Zr and Sn isotopes
from the proton drip line to the neutron drip line",
Phys. Rev. C 59 , 154-163 (1999).
M. Sambataro and N. Dinh Dang: "Variational approach to collective excitations", Phys. Rev. C 59,
1422-1431 (1999).
N. Dinh Dang, K. Tanabe, and A. Arima: "Dampingof double giant dipole resonance" , Phys. Rev. C 59,
3128-3138 (1999).
N. Dinh Dang, K. Tanabe, and A. Arima: "Evolutionof the hot giant dipole resonance as a manifestationof the order-and-chaos coexistence", Phys. Rev. C
60 , 034306-1-034306-7 (1999).
H. Okamura: "Three-body treatment of the (d,2He) reaction on the basis of the adiabatic approximation" ,Phys. Rev. C 60, 064602-1- 064602-8 (1999).
A. A. Korsheninnikov, M. Golovkov, A. Ozawa, E.
A. Kuzmin, E. Y. Nikolskii, K. Yoshida, B. G.
Novatskii, A. A. Ogloblin, I. Tanihata, Zs. Fiilop,
K. Kusaka, K. Morimoto, H. Otsu, H. Petrascu, andF. Tokanai: "Observation of an excited state in 7Hewith unusual strucuture", Phys. Rev. Lett. 82 ,271

3581-3584 (1999).
N. Iwasa, F. BOUE~, G. Sur6wka, K. Summerer, T.
Baumann, B. Blank, S. Czajkowski, A. Forster,M. Gai, H. Geissel , E. Grosse, M. Hellstrom , P.
Koczon, B. Kohlmeyer, R. Kulessa, F. Laue, C.
Marchand, T. Motobayashi, H. Oeschler, A. Ozawa,
M. S. Pravikoff, E. Schwab, W . Schwab, P. Senger,
J. Speer, C. Sturm, A. Surowiec, T. Teranishi, F.
Uhlig, A. Wagner, W. Walus, and C. A. Bertulani:"Measurement of the Coulomb dissociation of 8B at
254 MeV/nucleon and the 8B solar neutrino flux",
Phys. Rev. Lett. 83, 2910-2913 (1999).
T. Suzuki, H. Sakai, and T. Tatsumi: "The LandauMigdal parameters, g'NN and g'Ntl and pion condensation", Proc. Int. Conf. on Nuclear Responses andMedium Effects, Osaka, 1998-11 , edited by T. Noro,
H. Sakaguchi, H. Sakai, and T. Wakasa, Universal
Academy Press, Tokyo, pp. 77- 85 (1999).
K. Ishida, T. Matsuzaki, and K. Nagamine: "Recent
topics in muonic atom, molecule and muon catalyzed
fusion", Proc. Workshop on Atomic and Molecular
Processes in Space, Sagamihara, 1998-12 , edited by
Y. Ichikawa, Institute of Space and Astronautical
Science, pp. 37-40 (1999) .
K. Ishida: "Plans of high intensity muon channels at
RIKEN-RAL and KEK-MSL", Proc. Workshop on
High Intensity Secondary Beam with Phase Rotation, Uji, 1998-09, edited by Y. Kuno and N. Sasao,
Kyoto, pp. 128-135 (1999) .
K. Ishida, K. Nagamine, T. Matsuzaki, S. N.
Nakamura, N. Kawamura, S. Sakamoto, M. Iwasaki,
I. Watanabe, M. Tanase, M. Kato, K . Kurosawa, K.
Kudo, N. Takeda, and G. H. Eaton: "Recent p,CF research - p,CF experiment at RIKEN-RAL(l) X-ray
and neutron studies on muon to alpha sticking in
D-T p,CF" , Proc. Workshop on Ultra-high Intensity
Muon Beam and Muon Science in the 21st Century,
Tsukuba, 1999-03, edited by S. Sakamoto, High Energy Accelerator Research Organization, Tsukuba,
pp. 105-108 (1999).
K. Ishida, T. Matsuzaki, I. Watanabe, S. N. Nakamura,
Y. Matsuda, and K. Nagamine: "Design of an ultrahigh intensity muon channel for the second phase of
the RIKEN-RAL Muon Facility", Proc. Workshop
on Ultra-high Intensity Muon Beam and Muon Science in the 21st Century, Tsukuba, 1999-03, edited
by S. Sakamoto, High Energy Accelerator Research
Organization, Tsukuba, pp. 61-66 (1999).
K. Ishida, K. Nagamine, T. Matsuzaki, S. N.
Nakamura, N. Kawamura, S. Sakamoto, M. Iwasaki,
I. Watanabe, M. Tanase, M. Kato, K. Kurosawa, K.
Kudo, N. Takeda, and G. H. Eaton: "X-ray andneutron studies on muon to alpha sticking in D-Tmuon catalyzed fusion", RIKEN Rev., No. 20, pp.
3-7 (1999).
S. N. Nakamura, Y. Matsuda, K. Ishida, T. Matsuzaki,
I. Watanabe, K. Nagamine, M. Iwasaki, D. Tomono,
S. Sakamoto, and M. Gren: "A new approach to272

measure the positive muon lifetime and test the exponential decay law" , RIKEN Rev. , No. 20, pp. 5863 (1999).
T. Suzuki: "E1 x E1 and E1 x E2 giant resonances",
RIKEN Rev ., No. 23, pp. 119-122 (1999).
H. Kurasawa, N. Uchiyama, and T. Suzuki: "Giant
resonance states of atomic clusters", Tohoku LNS
Report LNS1011- 99, 181-189 (1999).

3.

Atomic and solid-state physics

Y. Kobayashi, J. Nakamura, A. Yoshida, Y. Watanabe,
N. Aoi , N. Inabe, M. Kase, A. Goto, Y. Yano, M.
Ishihara, F. Ambe, Y. Yoshida, K. Yukihira, K.
Hayakawa, M. Miyasaka, S. Hiyama, Y. Kobayashi,and S. Nasu: "In-beam Mossbauer spectroscopy using a 57Mn beam from RIPS of RIKEN", Proc.
Specialist Research Meet. on Solid State Physics
with Probes of Radiations and Nuclei (I), pp. 7173 (1997).
T. Kambara: "Atomic physics at the planned new
RIKEN facility", Hyperfine Interact. 115 , 101-106(1998).
A. Iwase, N. Ishikawa, Y. Chimi , K. Tsuru, H. Wakana,O. Michikami, and T . Kambara: "High energy
heavy ion irradiation damage in oxide superconductor EuBa2CU30y", Nucl. Instrum. Methods Phys.
Res. B 146, 557-564 (1998).
N. Kuroda, N. Ishikawa, S. Okayasu, A. Iwase,
H. Ikeda, R. Yoshizaki, and T. Kambara: "Vortex dynamics in Bi2+xSr2_(x+y)LayCu06+§ and
Bi2Sr2CaCu2 0y irradiated with heavy-ions: Correlation between the Bose-glass behavior and the coupling of pancake vortices", Nucl. Instrum. Methods
Phys. Res. B 146,572-576 (1998).
Y. Yamazaki: "Stabilized multiply excited states produced with highly charged ions passed through microcapillaries", Photonic, Electronic and Atomic
Collisions, Vienna, Austria, 1997-07, edited by F.
Aumayr and H. Winter, World Scientific, pp. 693702 (1998).
S. Okayasu, N. Kuroda, A. Iwase, and T. Kambara:"Recoupling vortices due to columnar defects in 3.5
GeV Xe-irradiated QMG-YBCO", Advances in Superconductivity XI (Proc. 11th Int. Symp. on Superconductivity (ISS'98)), Fukuoka, 1998-11, edited by
N. Koshizuka and S. Tajima, Springer-Verlag, Tokyo,
Hong Kong, pp. 287-290 (1999).
H. Ikeda, N. Kuroda, A. Iwase, T. Kambara, andR. Yoshizaki: "Vortex state of heavy ion irradiatedNi-doped Bi-2212", Advances in Superconductivity
XI (Proc. 11th Int. Symp. on Superconductivity(ISS '98)), Fukuoka, 1998-11, edited by N. Koshizuka
and S. Tajima, Springer-Verlag, Tokyo, Hong Kong,
pp. 291-294 (1999).
Y. Awaya, T. Kambara, and Y. Kanai: "Multiple Kand L-shell ionizations of target atoms by collisions

with high-energy heavy ions", Int. J. Mass Spectrom. 192, 49-63 (1999).
Y. Yamazaki: "Beam capillary spectroscopy", Int. J.
Mass Spectrom. 192,437-444 (1999).
T. Maruyama, T. Hasegawa, N. Komuro, H. Yamada,
W. Ohtsuka, K. Akimoto, Y. Kitajima, K. Maeda,
and E. Vagi: "Compensation centers in ZnSeTe", J.
Appl. Phys. 86, 5993-5999 (1999).
H. Sakairi, E. Vagi, and A. Koyama: "Annealing of
CU3Au irradiated with protons, a -particles and C
ions at liquid nitrogen temperature" , J. N ucl. Mater.
271/272 , 194- 199 (1999).
S. Uramoto: "Superexcited states of the hydrogenmolecule converging to the first excited state of thehydrogen molecular ion", J. Phys. Soc. J pn. 68 ,
1541-1547 (1999).
E. Vagi, T. Sasahara, T. Joh, M. Hacke, T. Urai,
T. Sasamoto, N. Tajima, T. Watanabe, and S. T.
Nakagawa: "Xe bubble formation in Xe-implanted
Fe as observed by the channelling method", J. Phys.
Soc. Jpn. 68 , 4037- 4044 (1999).
Y. Yamazaki: "Production of ultra slow antiprotons, its application to atomic collisions and atomic
spectroscopy-ASACUSA project", Nucl. Instrum.
Methods Phys. Res. B 154, 174-184 (1999).
B. Sulik, K. Tokesi, Y. Awaya, T. Kambara, and Y.
Kanai: "Single and double K-shell vacancy production in N 7 + + Ti collisions", Nucl. Instrum. Methods Phys. Res. B 154, 286-290 (1999).
Y. Zou, R. Hutton, S. Huldt, I. Martinson, K. Ando, T.
Kambara, H. Oyama, and Y. Awaya: "Improvementin the reliability of lifetime measurements for highly
charged ions in the 0.01-100-ns range", Phys. Rev.
A 60, 982-985 (1999).
Y. Morishita, S. Ninomiya, Y. Yamazaki, K. Komaki,
K. Kuroki, H. Masuda, and M. Sekiguchi: "Visible
light emission from slow highly charged ions transmitted through a Ni microcapillary", Phys. Scr. T
80,212-214 (1999).
M. Kitajima, Y. Nakai, Y. Kanai, Y. Yamazaki, and Y.
Itoh: "Crossed beam experiment for multi-electron
capture in ion-atom collision in the energy range of
10-100 eV /q", Phys. Scr. T 80, 377- 378 (1999).
K. Tokesi, Y. Awaya, T. Kambara, Y. Kanai, and B.
Sulik: "Double K-shell vacancy production in N 7 ++ Ti collisions", Phys. Scr. T 80,408-410 (1999).
K. Ishii, S. Kawae, T. Nakano, K. Ando, H. Oyama,
and T. Kambara: "Beam-foil spectra of highly
charged Neon ion in visible region", Phys. Scr. T
80, 458- 459 (1999).
Y. Zou, R. Hutton, S. Huldt, I. Martinson, K. Ando, H.
Oyama, B. Nystrom, T. Kambara, and Y. Yamazaki:"Limitations of the beam-foil method in lifetime
measurements" , Phys. Scr. T 80, 460- 462 (1999).
R. Hutton, Y. Zou , S. Huldt, 1. Martinson, K.
Ando, B. Nystrom, T. Kambara, H. Oyama, andY. Awaya: "A CCD detector system for beam-foil
spectroscopy", Phys. Scr. T 80, 532- 533 (1999).

N. Okabayashi, K. Kuroki, Y. Tsuruta, T. Azuma, K.
Komaki, and Y. Yamazaki: "Measurements of potential sputtered H+ with 2D position sensitive detector", Phys. Scr. T 80, 555-556 (1999).
K. Kuroki, T. Takahira, Y. Tsuruta, N. Okabayashi,
T. Azuma, K. Komaki, and Y. Yamazaki: "Charge
state dependence of proton sputtering from solid surfaces with slow highly charged ions", Phys. Scr. T
80,557-558 (1999).
N. Ishikawa, Y. Chimi, N. Kuroda, A. Iwase, and T.
Kambara: "Ion-velocity effects on defect production
in high-T c superconductors and metals irradiatedwith swift heavy ions", Phys. Scr. T 80, 559-561(1999).
N. Kuroda, N. Ishikawa, Y. Chimi, A. Iwase,
S. Okayasu, H. Ikeda, R. Yoshizaki, and T.
Kambara: "Vortex dynamics in Bi2(Sr,LahCu06+8
and Bi2Sr2CaCu208+8 single crystals with columnar
defects", Physica C 321, 143-150 (1999).
E. Vagi: "Formation of solid krypton bubbles in aluminium as investigated by a channelling method",Rad. Eff. Def. Sol. 148, 193-211 (1999).
N. Kawamura, K. N agamine, T. Matsuzaki, K. Ishida,
S. N. Nakamura, S. Sakamoto, I. Watanabe, M.
Iwasaki, M. Tanase, M. Kato, K. Kurosawa, K.
Kudo, N. Takeda, and G. H. Eaton: "Measurementsof He accumulation effect on muon catalyzed fusionin the solid/liquid D-T mixtures", RIKEN Rev., No.
20, pp. 14-17 (1999).
I. Shimamura: "Atomic physics of muon-catalyzed
fusion", Supercomputing, Collision Processes, andApplications, edited by Bell et al., Kluwer Academic/Plenum Publishers, New York, pp. 269-278(1999).

4.

Radiochemistry, radiation chemistry, and radiation biology

S. Gouthu, T. Arie, and I. Yamaguchi: "Uptake of
137 Cs and 90Sr by cucumber in three soil-types",
Comparative Evaluation of Environmental Toxicants: Health Effects of Environmental Toxicants
Derived from Advanced Technology, edited by J. Inaba and Y. Nakamura, National Institute of Radiological Sciences, pp. 275-276 (1998).
K. Kimura, W. Hong, J. Kaneko, and N. Itoh: "Extremely fast decay component of UV luminescencefrom 2-MeV /amu ion irradiated alumina", Nucl. Instrum. Methods Phys. Res. B 141,425-430 (1998).
K. Kimura and W. Hong: "Decay enhancement of selftrapped excitons at high density and low temperature in an ion-irradiated BaF 2 single crystal", Phys.
Rev. B 58, 6081-6089 (1998).
R. Hirunuma, K. Endo, S. Enomoto, S. Ambe, and
F. Ambe: "Study on the distribution of radioactive
trace elements in vitamin D-overloaded rats using
the multitracer technique" , Appl. Radiat. Isot. 50,
843-849 (1999).
273

I. Fujiwara, Y. Itoh, R . Iwata, F. Saito, and A. Goto:,,18F intense spot positron source for spin polarized
positron beam", Appl. Surf. Sci. 149,30- 33 (1999).
T. Abe: "A new mutation method for plants using
heavy-ion beams", Biosci. Ind. 57, 39- 40 (1999).
K. Sueki, K. Kikuchi, K. Akiyama, T. Sawa, M.
Katada, S. Ambe, F. Ambe, and H. Nakahara: "Formation of metallofullerenes with higher group elements", Chern. Phys. Lett. 300, 140- 144 (1999).
S. Ambe, T. Shinonaga, T. Ozaki, S. Enomoto, H.
Yasuda, and S. Uchida: "Ion competition effects on
the selective absorption of radionuclides by komatsuna (Brassica rapa var. perviridis) " , Environ. Exp.
Bot. 41, 185-194 (1999).
S. Ambe, T. Ozaki, S. Enomoto, and T. Shinonaga:"Multitracer study on the soil-to-plant transfer of radionuclides in komatsuna at different growth stages" ,Environ. Technol. 20, 111-116 (1999).
S. Gouthu, R. G. Weginwar, T. Arie, S. Ambe, T.
Ozaki, S. Enomoto, F. Ambe, and I. Yamaguchi:"Subcellular distribution and translocation of radionuclides in plants", Environ. Toxicol. Chern. 18,
2023-2027 (1999).
M. Kikuchi, I. Narumi, S. Kitayama, H. Watanabe,
and K. Yamamoto: "Genomic organization of theradioresistant bacterium Deinocuccus radiodurans:
Physical map and evidence for multiple replicons" ,FEMS Microbiol. Lett. 174, 151- 157 (1999).
T. Arie, S. Gouthu, H. Hirata, S. Ambe, and I.
Yamaguchi: "Plant uptake of radionuclides and rhizosphere factors", Final Reports on Nuclear CrossOver Research (II): Transfer Models and Parametersof Radionuclides in Terrestrial Environment, editedby Promotion Committee on Nuclear Cross-Over Research, Tokyo, pp. 97-107 (1999).
K. Ushida, Y. Yoshida, T. Kozawa, S. Tagawa, andA. Kira: "Evidence of oxidation of aromatic hydrocarbons by chloromethyl radicals: Reinvestigation ofintersolute hole transfer using pulse radiolysis", J.
Phys. Chern. A 103, 4680--4689 (1999).
T. Nozaki, Y. Itoh, Z.-L. Peng, N. Nakanishi, A. Goto,
Y. Ito, and H. Yoshida: "Preparation of 18F source
for slow positron beam by proton bombardment of
180-water", J. Radioanal. N ucl. Chern. 239, 175178 (1999).
R. Hirunuma, N. Sotogaku, K. Endo, S. Enomoto, S.
Ambe, and F. Ambe: "Time dependence of distribution of radioactive trace elements in Se-deficient
rats: Application of the multitracer technique" , J.
Radioanal. Nucl. Chern. 239, 213- 215 (1999).
S. Oishi, R. Amano, A. Ando, S. Enomoto, and F.
Ambe: "Simultaneous biobehavior of trace elements,
Sc, Mn, Fe, Co, Zn, Se, Rb, and Zr in the brain
and other organs of C57BL/6N mice", J. Radioanal.
Nucl. Chern. 239, 411-416 (1999).
N. Sotogaku, K. Endo, R. Hirunuma, S. Enomoto, S.
Ambe, and F. Ambe: "Binding properties of various
metals to blood components and serum proteins: A
274

multitracer study", J. Trace Elements Med. BioI.
13, 1-6 (1999).
T. Arie, S. Gouthu , H. Hirata, S. Ambe, and I.
Yamaguchi: "Plant uptake of radionuclides andrhizosphere factors", JAERI-Conf., edited by S.
Matsumoto, S. Uchida, H. Yamazaki, and H.
Amano, Japan Atomic Energy Research Institute,
Tokaimura, pp. 202- 212 (1999).
K. Ishioka, K. Ushida, K. G. Nakamura, S. Hishita,
and M. Kitajima: "Effect of ion irradiation on coherent phonon dynamics in bismuth", J pn. J. Appl.
Phys. 38, L446-L447 (1999).
Y. Kagawa, T. Shimazu, A. Gordon, N. Fukunishi,
N. Inabe, M. Suzuki, M. Hirano, T. Kato, M.
Watanabe, F. Hanaoka, and F. Yatagai: "Complex
hprt deletion events are recovered after exposure ofhuman lymphoblastoid cells to high-LET carbon andneon ion beams", Mutagenesis 14, 199- 205 (1999).
K. Kimura, W. Hong, J. Kaneko, and N. Itoh: "Stimulated emission and exciton complex in some insulator
crystals irradiated by heavy ions" , N ucl. Instrum.
Methods Phys. Res. B 154, 318-324 (1999).
K. Kimura, J. Kaneko, S. Sharma, W. Hong, and N.
Itoh: "Stimulated emission at 326 nm and an ultrafast 100-ps-lived luminescence component by ion
irradiation of a-alumina", Phys. Rev. B 60, 1262612634 (1999).
H. Iwai, T. Abe, S. Yoshida, H. Kamada, and S.
Satoh: "Production of non-organogenic and loosely
attached call us in leaf disk cultures of haploid Nicotiana plumbaginifolia by 14N ion beam irradiation",
Plant Biotechnol. 16, 307- 309 (1999).
T. Shinonaga, G. Prohl, H. Muller, and S. Ambe: "Experimentally determined mobility of trace elements
in soybean plants" , Sci. Total Environ. 225, 241248 (1999).

5.

Material analysis

K. Hasegawa, K. Maeda, S. Nakayama, A. Tonomura,and H. Hamanaka: "Crystal spectrometer PIXE system equipped with a multi-anode PSPC" , Rep. Res.
Cen. Ion Beam Technol., Hosei Univ. , No. 18, pp.
35- 39 (1997).
K. Hasegawa, K. Maeda, S. Nakayama, A. Tonomura,and H. Hamanaka: "A multianode position-sensitive
proportional counter for in-air high-resolution PIXE
using a crystal spectrometer", Int. J. PIXE 8,47- 56(1998).
Y. Tokimitsu , K. Maeda, S. Murao, and E. Henseler:"External-PIXE identification of material for popular music pipes during the late Meiji era, Japan",Int. J. PIXE 8 , 155- 166 (1998).
H. Hamanaka, A. Tonomura, K. Hasegawa, K. Maeda,
and S. Yumoto: "PIXE analysis of Al compounds
using a wavelength-dispersive spectrometer with
PSPC(l)" , Rep. Res. Cen. Ion Beam Technol.,
Hosei Univ., Suppl. No. 16, pp. 87- 92 (1998).

K. Maeda, A. Tonomura, H. Hamanaka, and K.
Hasegawa: "Chemical shift measurements of PIXE
spectra using a position-sensitive crystal spectrometer", Nucl. Instrum. Methods Phys. Res. B 150,
124- 128 (1999).
H. Hamanaka, A. Tonomura, K. Hasegawa, K. Maeda,
and S. Yumoto: "PIXE analysis of Al compounds

using a wavelength dispersive spectrometer 'w ith
PSPC(2)", Rep. Res. Cent. Ion Beam Technol.
Hosei Univ., Suppl. No. 17, pp. 141- 145 (1999).
W. Hong, S. Hayakawa, K. Maeda, S. Fukuda, and
Y. Gohshi: "Light element analysis in steel by highenergy heavy-ion time of flight elastic recoil detection
analysis" , Spectrochim. Acta B 54, 151- 157 (1999).

275

VIII. LIST OF PREPRINTS1999
RIKEN-AF-NP
303 V. B. Carlson and D. Hirata: "The Dirac-Hartree-Bogoliubov approximation for finite nuclei"
304 H. Ogawa, K. Asahi, K. Sakai, A. Yoshimi, M. Tsuda, Y . Uchiyama, T. Suzuki, K.Suzuki, N. Kurokawa,
M. Adachi , H. Izumi, H. Ueno, T. Shimoda, S. Tanimoto, N. Takahashi, W.-D. Schmidt-Ott, M. Schafer, S.
Fukuda, A. Yoshida, M. Notani, T. Kubo, H. Okuno, H. Sato, N. Aoi, K. Yoneda, H. Iwasaki, N. Fukuda,
N. Fukunishi, M. Ishihara, and H. Miyatake: "Magnetic moment and electric quadrupole moment of the
18N ground state"
305 A. Ansari, M. Oi, N. Onishi, and T. Horibara: "High exotics in osmium isotopes"
306 A. Ansari, M. Oi, N. Onishi, and T. Horibata: "High spin structure of 182, 184 0 S in tilted axis cranking
approach"
307 Y. Mochizuki, K. Takahashi, H.-Th. Janka, W. Hilenzaki, and R. Diehl: ,,44Ti: Its effective decay rate inyoung supernova remnants, and its abundance in Cas-A"
308 H. Madokoro and M. Matsuzaki: "Relativistic and non-relativistic mean field investigation of the superdeformed bands in 62 Zn"
309 N. Saito: "Measurement of anti-quark polarization in the proton and its flavor decomposition with PHENIX
at RHIC"
310 Y. Goto: "Gluon polarization measurement with photon detection at PHENIX"
311 M. R. Ahmady and E. Kou: "A more careful estimate of the charm content of ry"
312 A. A. Korsheninnikov , M. S. Golovkov, A. Ozawa, E. A. Kuzmin , E. Yu. Nikolskii, K. Yoshida, B. G.
Novatskii, A. A. Ogloblin , 1. Tanihata, Z. Fulop, K. Kusaka, K . Morimoto, H. Otsu, H. Petrascu, and H.
Tokanai: "Observation of the 7He excited state with unusual structure"
313 Y. Mochizuki , T. Izuyama, and 1. Tanihata: "Dynamics of exotic nuclear rod formation for the origin ofneutron star glitches"
314 N. Itagaki and S. Okabe: "Nucleon-alpha chain states in lOBe"
315 N. Dinh Dang, K. Tanabe , and A. Arima : "Evolution of the hot giant dipole resonance as a manifestationof the order-and-chaos coexistence"
316 A. Kohama, K. Yazaki, and R. Seki: "Correlation and finite interaction-range effects in high-energy electron
inclusive scattering"
317 T. Suzuki, H. Sakai, and T. Tatsumi: "The Landau-Migdal parameters, g'NN and g/ND. and pion condensation"
318 T . Suzuki: "E1 x E1 and E1 x E2 giant resonances*: Effects of the exchange current on the excitation of
double giant resonance states"
319 H. Okamura: ((Three-body treatment of the (d, 2He ) reaction on the basis of the adiabatic approximation"
320 V. Yu. Denisov and S. Yamaji:
approach"276((One and double-phonon giant monopole resonances in the nonlinear

321 T. Nakamura, N. Fukuda, T. Kobayashi, N. Aoi, H. Iwasaki, T. · Kubo, A. Mengoni, M. Notani, H. Otsu,
H. Sakurai, S. Shimoura, T. Teranishi, Y. Watanabe, K. Yoneda, and M. Ishihara: "Coulomb dissociationof 19C and its halo structure"
322 Y. Goto: "Sensitivity to gluon polarization at RHIC"
323 N. Saito: "RHIC spin physics-status of the polarized collider and spin-flavor structure of the nucleon"
324 N. Dinh Dang, K. Eisenman , J. Seitz, and M. Thoennessen: "Statistical analysis of the hot giant dipole
resonance with the phonon damping model"
325 N. Dinh Dang, K. Tanabe, and A. Arima: "Damping of multiphonon giant resonances"
326 A. Ansari, N. Dinh Dang, and A. Arima: "Hot giant dipole resonance in static path approximation"
327 H. Kurasawa and T. Suzuki: "Effects of the Dirac sea on the giant monopole states"
328 T. Maruyama and S. Chiba: "Isoscalar giant quadrupole resonance state in the relativistic approach withthe momentum-dependent self-energies"
329 N. Itagaki and S. Aoyama: "Systematic study on He-isotope with antisymmetrized molecular dynamics plus
generator coordinate method"
330 T. Uesaka, H. Sakai, H. Okamura, T. Ohnishi, Y. Satou, S. Ishida, N. Sakamoto, H. Otsu T. wakasa, K.
Itoh, K. Sekiguchi, and T. Wakui: "Polarization correlation coefficient for the 3He(d~p)4He reaction"
331 N. Dinh Dang, T. Suzuki, and A. Arima: "Giant dipole resonance in neutron-rich nuclei within the phonon
damping model"
332 S. Sugimoto, K. Sumiyoshi, D. Hirata, B. V. Carlson, 1. Tanihata, and H. Toki: "Systematic study of triaxial
deformation in the relativistic mean field theory"
333 N. Itagaki and S. Okabe: "Molecular orbital structures in lOBe"
334 M. Tanifuji , S. Ishikawa, Y. Iseri, T. Uesaka, 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+ 3 He backward elastic scattering at intermediate energies"
335 M. Oi, A. Ansari, T. Horibata, and N. Onishi: "Wobbling motion in the multi-bands crossing region"
336 K. Tanabe and N. Dinh Dang: "Exact form of the random phase approximation equation at finite temperature including the entropy effect"
337 K. Sumiyoshi, H. Suzuki, K. Otsuki , M. Teranishi, and S. Yamada: "Hydrodynamical study of neutrinodriven wind as an r-process site"

RIKEN-AF -NC
12 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: "Production of highly charged ions in the RIKEN 18 GHz ECR ion
source using an electrode in two modes"
13 G. Shirkov: "Multicomponent consideration of electron fraction of ECR source plasma"
14 E. Syresin, T. Tanabe, T. Rizawa, T. Katayama, and 1. Mashkov: "Simulation and design of an electron
cooling system for ACR"
277

15 S. Kondrashev: "Laser ion source-intense pulsed source of highly-charged ion beams for RIKEN MUSES
Project"
16 P . Zenkevich and T. Katayama: "Storage of ion beams in ACR by use of charge-exchange injection"

278

IX. PAPERS PRESENTED AT MEETINGS
1.

Accelerator
physics

development

andaccelerator

1. Watanabe, T. Tanabe, K. Ohtomo, and T.
Katayama: "Electron cooling at ACR in MUSES
project", 6th European Particle Accelerator Conf.
(EPAC '98) , (MSL), Stockholm, Sweden, June
(1998).
T. Tanabe, Y. Watanabe, and M. Kase: "RIKENRIBF control system", 2nd Workshop on PCs andParticle Accelerator Control (PCaPAC '99), (KEK) ,Tsukuba, Jan. (1999).
T. Tanabe, K. Ohtomo, T. Rizawa, and T. Katayama:"Development of MUSES-ACR electron cooler",
1999 Particle Accelerator Conf.
(PAC '99),(Brookhaven National Laboratory), New York, USA ,Mar. (1999).
O. Kamigaito: "A pre-injector RFQ and a 'chargestate multiplier ' system of the RIKEN heavy ion!inac", 4th Korea-Japan Joint Symp. on Cyclotrons
and Nuclear Science, (Korea Cancer Center Hospital), Seoul, Korea, Mar. (1999).
T. Tanabe, T. Rizawa, K. Ohtomo, T. Katayama, E.
Syresin, 1. Meshkov, and A. Yamashita: "Design ofan electron cooling device for the accumulator cooler
ring in MUSES project", ECOOL '99 Workshop on
Electron Cooling and Related Topics Incorporating
5th Workshop on Medium Energy Electron Cooler(MEEC), (Svedberg Laboratory), Uppsala, Sweden,
May (1999).
M. Kidera, K. Higurashi, T. Nakagawa, S. Biri, G.
Shirkov, Y. Miyazawa, M. Hemmi, T. Chiba, T.
Kageyama, M. Kase , A. Goto, and Y. Yano: "Effect of biased electrode to high energetic electronsin plasma of RIKEN 18 GHz ECRIS", 14th Int.
Workshop on ECR Ion Sources(ECRIS99), (CERN),
Geneva, Switzerland, May (1999) .
T. Tominaka, T. Kawaguchi, J.-W. Kim, H. Okuno, J.
Ohnishi, A. Goto, and Y. Yano: "RIKEN Superconducting Ring Cyclotron (III): Quench protection of
sector magnet", 60th Meet. on Cryogenics and Superconductivity, (Cryogenics Association of Japan) ,Sapporo, June (1999).
A. Goto and Y. Yano: "RIKEN Superconducting Ring
Cyclotron (I): Overview and status", 60th Meet. on
Cryogenics and Superconductivity, (Cryogenics Association of Japan), Sapporo, June (1999).
A. Goto: "Superconducting ring cyclotron for RIKEN
RI Beam Factory", 1999 1st Chou-Dendou Ouyou
Kenkyuukai, Tsukuba, July (1999).
S. Bhattacharjee and H. Amemiya: "Build up characteristics of a plasma produced by high power shortpulse microwaves", 24th Int. Conf. on Phenomena in Ionized Gases (ICPIG), Warsaw, Poland , July
(1999) .

S. Bhattacharjee and H. Amemiya: "Production of microwave plasma in a waveguide with a dimension below cutoff", Int. Symp. PLASMA'99 on Researchand Applications of Plasmas, (Polish Academy of
Sciences) , Warsaw, Poland, July (1999).
O. Kamigaito, M. Kase, Y. Miyazawa, T. Chiba, M.
Hemmi, S. Kohara, E. Ikezawa, A. Goto, and Y.
Yano: "Construction of the first unit of the chargestate multiplier system for the RIKEN RI-Beam Factory", 24th Linear Accelerator Meet. in Japan, (Laboratory of Energy Convension Engineering, Graduate School of Engineering, Hokkaido University),
Sapporo, July (1999).
K. Higurashi, T. Nakagawa, M. Kidera, Y. Miyazawa,
M. Hemmi, T. Chiba, M. Kase, T. Kageyama, A.
Goto, and Y. Yano: "The effect of an electrode inplasma chamber of electron cyclotron resonance ion
source (ECRIS)", 1999 Fall Meet. of Physical Society of Japan, Matsue, Sept. (1999).
T. Kurita, T. Nakagawa, T. Kawaguchi, and S. M. Lee:
"Design of ECR ion source using liquid-helium-freesuperconducting solenoid coils", 1999 Fall Meet. ofPhysical Society of Japan, Matsue, Sept. (1999).
S. Bhattacharjee and H. Amemiya: "Pulsed microwave
plasma production in a conducting tube with a radius below cutoff", 11th Int. School on Vacuum,
Electron and Ion Technologies (VEIT'99), (Institute of Electronics at the Bulgarian Academy of Sciences), Varna, Bulgaria, Sept. (1999).
M. Kidera:"Status and future plan of RIKENECRIS", Int. Workshop on Ion Sources for Producing the Intense Beam of Multi-charged Metallic Ions,
Wako, Sept. (1999).
T. Takeuchi: "Future plan of laser ion source at
RIKEN", Int. Workshop on Ion Sources for Producing the Intense Beam of Multi-charged Metallic
Ions, Wako, Sept. (1999).
M. Kase, T. Masuoka, J. Ohnishi, T. Tanabe, andY. Watanabe: "CORBA based control system with
RTOS on VME/CPCI", 7th Int. Conf. on Accelerator and Large Experimental Physics Control Systems (I CALEPCS) 99 , (Sincrotrone 'frieste), 'frieste,
Italy, Oct. (1999).
K. Higurashi, T. Nakagawa, M. Kidera, Y. Miyazawa,
M. Hemmi, T. Chiba, M. Kase, T. Kageyama, A.
Goto, and Y. Yano: "The effect of an electrode inplasma chamber of RIKEN 18kHz ECRIS(Electron
Cyclotron Resonance Ion Source)", 12th Symp. on
Accelerator Science and Technology, Wako, Oct.
(1999) .
O. Kamigaito, M. Kase , Y. Miyazawa, T . Chiba, M.
Hemmi, N. Sakamoto, S. Kohara, E. Ikezawa, A.
Goto , and Y. Yano: "Construction of the chargestate multiplier system for the RIKEN RI-Beam Factory" , 12th Symp. on Accelerator Science and Technology, Wako, Oct. (1999).
279

T. Rizawa, K. Ohtomo, and T. Katayama: "Electron
coolers in MUSES project", 12th Symp. on Accelerator Science and Technology, Wako, Oct. (1999).
T. Rizawa, A. Yamashita, S. Takama, M. Ushijima,
T. Katayama, and T. Tanabe: "Experimental studies of discharge under magnetic field for the electron
gun design of the ACR electron cooler", 12th Symp.
on Accelerator Science and Technology, Wako, Oct.
(1999).
A. Goto, M. Kase, J. Ohnishi, O. Kamigaito, N.
Sakamoto, K. Ikegami, K. Sugii, H. Okuno, Y.
Miyazawa, T. Hiasa, Y. Kumata, and Y. Yano:"Construction of the IRC for RIKEN RI-Beam Factory", 12th Symp. on Accelerator Science and Technology, Wako, Oct. (1999).
S. Bhattacharjee and H. Amemiya: "Characteristics
of a plasma produced by high power short pulse
microwaves", 41st Ann. Meet. of the Division of
Plasma Physics, (American Physical Society), Seattle, USA, Nov. (1999).
A. Goto: "Non-nuclear physics researchers at RIKEN
accelerator research facility", BATAN-JAIF Bilateral Seminar on Accelerator Technology and Its
Applications, (Research and Development Centre
for Advanced Technology), Yogyakarata, Indonesia,
Nov. (1999).
T. Tominaka, H. Okuno, and T. Kubo: "2D magnetostatic field calculation with mathematica", 61st
Meet. on Cryogenics and Superconductivity, (Cryogenics Association of Japan), Hachioji, Nov. (1999).

2.

Nuclear physics and nuclear instrumentation

I. Tanihata: "The RI Beam Factory and planned experiments related to astrophysics", Int. Conf. on
Neutron Stars and Pulsars: Thirty Years after the
Discovery, (Rikkyo University), Tokyo, Nov. (1997).
I. Tanihata: "New horizon in nuclear physics and astrophysics using radioactive nuclear beams", 11th
Nishinomiya-Yukawa Memorial Symp., Hyogo , Nov .
(1997) .
T. Kishida: "Windowless gas target system for high intensity beam", 53rd Ann. Meet. of Physical Societyof Japan, Funabashi, Apr. (1998).
A. Ozawa, A. A. Korsheninnikov, Y. Ogawa, I.
Tanihata, and K. Yoshida: "Measurements of interaction cross-sections for C-isotopes at relativistic energies", 74th Korean Physical Society Meet. , Seoul,
Korea, Apr. (1998).
T. Matsuzaki, K. N agamine, K. Ishida, S. N.
Nakamura, N. Kawamura, M. Tanase, M. Kato, K.
Kurosawa, M. Hashimoto, H. Sugai, K. Kudoh, N.
Takeda, and G. H. Eaton: "Muon catalyzed fusion
and muon to 3He transfer in solid T2 studied by xray and neutron detection" , Monte Verita Workshop
on Exotic Atoms , Molecules and Muon Catalyzed
Fusion, (Paul Scherrer Institute and University ofFri bourg), Ascona, Switzerland, July (1998).
280

T . Matsuzaki, K. Nagamine, M. Tanase, M. Kato, K.
Kurosawa, K. Ishida, S. N. Nakamura, I. Watanabe,
and G. H. Eaton: "Tritium gas handling system
for muon catalyzed fusion research at RIKEN-RAL
muon facility", Monte Verita Workshop on Exotic Atoms , Molecules and Muon Catalyzed Fusion,(Paul Scherrer Institute and University of Fribourg),
Ascona, Switzerland, July (1998).
Y. Mochizuki: "The long half-life of highly ionized
44Ti", Nuclei in the Cosmos V, VoIos, Greece, July
(1998).
Y. Mochizuki: "A microscopic model of neutron starglitches", Seminar at Max-Plank Institut fur Astraphysik, Garhing, Germany, July (1998).
T. Fujita, K. Tsuruta, T. Yagita, H. Okuda, M.
Kondo, Y. Tachikawa, H. Urabe, M. Nakamura, K.
Shigenaga, H. Nakamura, K . Sagara, T. Nakashima,and H. Akiyoshi: "Precise measurement of Ay forthe nd scattering at 16 MeV", 1998 Fall Meet. ofPhysical Society of Japan, Akita, Oct. (1998).
T. Onishi, T. Kawa, K. Matsuta, M. Mihara, M.
Fukuda, T. Minamisono, T. Miyake, M. Sasaki, T.
Yamaguchi, K. Sato, K. Minamisono, A. Morisita,
K. Tanaka, K. Kidera, T. Ohtsubo, S. Momota,
Y. Nojiri, A. Kitagawa, M. Torikoshi, S. Kouda,
S. Nishio, A. Ozawa, K. Yoshida, I. Tanihata, S.
S Hanna, J. R. Alonso, G. F. Krebs, and T. J.
M. Symons: "The quadrupole moments of 27Si and39Ca" , 1998 Fall Meet. of Physical Society of Japan,
Akita, Oct. (1998).
T. Matsuzaki: "Studies on j.LCF and muon transfer inpure T2 target", RIKEN Symp. on Muon Science'98: New Direction in Muon Catalyzed Fusion j.LSR
Studies and Fundamental Muon Physics, Wako, Oct.
(1998).
N. Kawai, M. Matsuoka, A. Yoshida, T. Mihara, T.
Kotani, H. Negoro, Y. Shirasaki, I. Sakurai, K.
Torii, H. Tsunemi , E. Miyata, M. Yamauchi, andK. Yoshida: "MAXI (Monitor of All-sky X-ray Image) for JEM on the space station", Small Missions for Energetic Astrophysics: Ultraviolet throughGamma-Ray, (Los Alamos National Laboratory),
Los Alamos, USA , Feb. (1999).
K. Yoneda, H. Sakurai, N. Aoi, N. Fukuda, T. Gomi , E.
Ideguchi, N. Imai , H. Iwasaki, T. Kubo, Z. Liu, S. M.
Lukyanov, T. Nakamura, M. Notani, H. Ogawa, Y.
E. Penionzhkevich, W. D. Schmidt-Ott, S. Shimoura,
E. Sokol, Y. Watanabe , A. Yoshida, X. Zhou, and
M. Ishihara: "Measurements of beta decay half lives
and betadelayed neutron emission probabilities fornuclei near the neutron drip line (Z=12-14)", 54th
Ann. Meet. of Physical Society of Japan, Higashihiroshima, Mar. (1999).
F. Tokanai, K. Morimoto, M. Kurata, I. Tanihata, andS. Yamada: "Development of time-of-flight detector
with streak camera I", 54th Ann. Meet. of PhysicalSociety of Japan, Higashihiroshima, Mar. (1999).
H. Madokoro and M. Matsuzaki: "Systematic study ofthe superdeformed bands in the A=60 mass region" ,54th Ann. Meet. of Physical Society of Japan, Higashihiroshima, Mar. (1999).
T. Matsuzaki, K. Nagamine, K. Ishida, S. N.
Nakamura, N. Kawamura, Y. Matsuda, S. Sakamoto,
M. Tanase, M. Kato, K. Kurosawa, H. Sugai, K.
Kudo, N . Takeda, and G. H. Eaton: "Muon catalyzed D-T fusion experiment at RIKEN-RAL muon
facility (12)", 54th Ann. Meet. of Physical Societyof Japan, Higashihiroshima, Mar. (1999).
K. Sumiyoshi, H. Suzuki, and S. Yamada: "Hydrodynamics of neutrino-driven wind for r-process", 54th
Ann. Meet. of Physical Society of Japan, Higashihiroshima, Mar . (1999).
A. Ozawa, O. Bochkarev, L. Chulkov, D. Cortina-Gil,
H. Geissel, M. Hellsroem, M. Ivanov, R. Janik,
K. Kimura, T. Kobayashi, A. A. Korsheninnikov,
G. Muenzenberg, F. Nickel, A. A. Ogloblin, M.
Pfutzner, V. Pribora, C. Sheidenberger, H. Simon,
B. Sitar, T. Suzuki, P. Strmen, K. Suemmerer, I.
Tanihata, M. Winkler, and K. Yoshida: "Measurements of interactions cross-sections for oxygen isotopes", 54th Ann. Meet. of Physical Society ofJapan, Higashihiroshima, Mar. (1999).
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 ofsuperconducting devices for radiation detection at
RIKEN", CRL(Communications Research Laboratory) Int. Symp ., Tokyo, Mar. (1999).
K. Ishida: "Second phase of RIKEN-RAL", MSL99
Workshop on Super High-Intensity Muon Beam andMuon Science in 21st Century, (Meson Science Laboratory, High Energy Accelerator Research Organization; RIKEN) , Tsukuba, Mar. (1999).
T. Matsuzaki, K. Ishida, S. N. Nakamura, and N.
Kawamura: "Recent f..LCF research - f..LCF experiment
at RIKEN-RAL", MSL99 Workshop on Super HighIntensity Muon Beam and Muon Science in 21st Century, (Meson Science Laboratory, High Energy Accelerator Research Organization; RIKEN), Tsukuba,Mar. (1999).
T. Suzuki: "E1 x E1 and E1 x E2 giant resonances",
RIKEN Symp. and Workshop on Selected Topics in
Nuclear Collective Excitations, Wako, Mar. (1999).
S. Yamaji: "Damping of isoscalar monopole resonanceat highly excited nuclei", RIKEN Symp. and Workshop on Selected Topics in Nuclear Collective Excitations, Wako, Mar. (1999).
Y. Mochizuki: "Seeking mysterious universe with RI",
Tokubetsu-Danwa-Kai, Nagoya University, Nagoya,Mar. (1999).
K. Ishida:"Muon catalyzed fusion experiments,
present status and future plans", Workshop on Intensity Secondary Beam with Phase Rotation, (Institute of Advanced Energy, Kyoto University), Uji,
Mar. (1999).
K. Ishida: "Super-super muon channel at RAL",

Workshop on Intensity Secondary Beam with Phase
Rotation, (Institute of Advanced Energy, Kyoto University), Uji, Mar. (1999).
T. Suzuki: "Sum rule approach to double giant resonances", Double Giant Resonances in Nuclei, (European Center for Theoretical Studies in Nuclear
Physics and Related Areas), Trento, Italy, May(1999).
N. Dinh Dang, K. Tanabe, and A. Arima: "Damping of double giant dipole resonance", Double Giant
Resonances in Nuclei, (European Center for Theoretical Studies in Nuclear Physics and Related Areas),
Trento, Italy, May (1999).
N. Dinh Dang, K. Tanabe, and A. Arima: "Shape evolution of the hot giant dipole resonance", Int. Conf.
on Achievements and Perspectives in Nuclear Structure, (Institute of Nuclear Physics NCSR Demokritos), Crete, Greece, July (1999).
H. Madokoro, J. Meng, M. Matsuzaki, and S. Yamaji:"Relativistic tilted axis cranking", Int. Symp. on
Models and Theories of the Nuclear Mass, Wako,
July (1999).
K. Sumiyoshi: "Unstable nuclei and EOS table for supernova explosion and r-process in relativistic many
body approach", Int. Symp. on Models and Theories of the Nuclear Mass, Wako, July (1999).
A. Yoshida: "Fusion cross section of neutron-rich Be
isotopes 1l,lO,9Be+ 209 Bi", Workshop on the Nuclear
Sciences of the Heaviest Elements, (JAERI), Tokaimura, July (1999).
K. Sekiguchi, H. Sakai, H. Okamura, N. Sakamoto, T.
Uesaka, A. Tamii, Y. Satou, T. Ohnishi, T. Wakasa,
K. Yako, S. Fukusaka, K. Suda, S. Sakoda, H. Kato,
Y. Maeda, K. Itoh, and T. Niizeki: "Measurement ofcross sections and vector and tensor analyzing powers for d-p elastic scattering at Ed = 270 MeV",
Asia Pacific Conf. on Few-Body Problems in Physics(APFB 99), (Science University of Tokyo), Chiba,
Aug. (1999).
T. Uesaka, H. Sakai, H. Okamura, J. Tamii, Y. Satou,
T. Ohnishi, N. Sakamoto, K. Itoh, K. Sekiguchi,
K. Yako, S. Sakoda, K. Suda, and T. Wakasa:"3He(d,p)4He reaction at intermediate energies",
Asia Pacific Conf. on Few-Body Problems in Physics(APFB 99), (Science University of Tokyo), Chiba,
Aug. (1999).
K. Naito, T. Umekawa, and M. Oka: "Study of linear
sigma model at finite temperature using the nonperturbative renormalization group" , Kiken 'Thermal Field Theory and Its Application', (Yukawa Institute for Theoretical Physics, Kyoto University),
Kyoto , Aug. (1999).
T. Uesaka, H. Sakai, H. Okamura, A. Tamii, Y. Satou,
T. Ohnishi, N. Sakamoto, K. Itoh, K. Sekiguchi,
K. Yako, S. Sakoda, K. Suda, and T. Wakasa:"3 He(d ,p)4He reaction at intermediate energies", 4thWorkshop on Polarized Nuclear Fusion, (ResearchCenter for Nuclear Physics, Osaka University), Os281

aka, Aug. (1999).
K . Yoneda, T. Gomi, H. Sakurai, T . Motobayashi,
N. Aoi, N. Fukuda, U . Futakami, Z. Gacsi, K.
Higurashi, N. Imai, N. Iwasa, H. Iwasaki, M. Kunibu,
M. Kurokawa, T. Kubo, 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: "Spectroscopy of neutronrich nuclei via the projectile-fragmentation reactionof unstable nuclei 36Si", 1999 Fall Meet. of PhysicalSociety of Japan, Matsue, Sept. (1999).
T. Gomi, K. Yoneda, H. Sakurai, S. Shimoura, 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. Takeuchi, Y.
Watanabe, K . Yamada, Y. Yanagisawa, K. Yo go ,A. Yoshida, and M. Ishihara: "Production rates of
excited unstable nuclei by the projectile fragmentation of 36Si" , 1999 Fall Meet. of Physical Society ofJapan, Matsue, Sept. (1999).
T. Minemura, T. Motobayashi, S. Shimoura, H.
Murakami, Y. Ando, T. Teranishi, N. Aoi, Zs.
Fiilop, M. Hirai, H. Iwasaki, N. Imai, N. Iwasa, M.
Kurokawa, H. Akiyoshi, Y. Yanagisawa, Y. Iwata,
S. Ozawa, S. Takeuchi, K. Higurashi, M. Serata, H.
Kobayashi, K. Yamada, T. Gomi, H. Sakurai, K.
Yoshida, Z. Liu, and M. Ishihara: "Coulomb dissociation of 12N and 13 0", 1999 Fall Meet. of PhysicalSociety of Japan, Matsue, Sept. (1999).
K . Suda, H. Okamura, N. Sakamoto, A. Tamii, T.
Uesaka, T. Ohnishi, K. Sekiguchi, J. Nishikawa, H.
Kato, M. Hatano, and H. Sakai: "Absolute calibration of the deuteron beam polarization at intermediate energies via the 12C(d, a) reaction", 1999 Fall
Meet. of Physical Society of Japan, Matsue, Sept.
(1999).
K. Naito, Y. Nemoto, K. Yoshida, M. Takizawa, andM. Oka: "Study of chiral symmetry breaking using the CJT effective potential", 1999 Fall Meet. ofPhysical Society of Japan, Matsue, Sept. (1999).
H. Madokoro, J. Meng, M. Matsuzaki, and S. Yamaji:"Relativistic mean field model applied to tilted axis
rotation", 1999 Fall Meet. of Physical Society ofJapan, Matsue, Sept. (1999).
K. Sumiyoshi, H. Suzuki, K. Otsuki, M. Terasawa, andS. Yamada: "r-Process condition by simulation ofneutron-driven wind", 1999 Fall Meet. of PhysicalSociety of Japan, Matsue, Sept. (1999).
K. Ishida: "Design of ultra intense muon channel" , 1999 Nendo Zenki Kyoudou Riyou Jikken
Houkokukai & Meson Science Working Group Workshop, (Meson Science Laboratory, High Energy Accelerator Research Organization; Meson Science Association), Tsukuba, Sept. (1999).
T . Uesaka, H. Sakai, H. Okamura, J. Tamii, Y.
Satou , T. Ohnishi, N. Sakamoto, T. Wakasa, K.
Itoh, K. Sekiguchi, K. Yako , S. Sakoda, K. Suda,
282

M. Kurokawa, T. Motobayashi, S. Shimoura, H.
Akiyoshi, T. Teranishi, S. Takeuchi, H. Iwasaki,
N. Imai, T. Gomi, M. Serata, Y. Yanagisawa, S.
Kubono, S. Yamamoto, T. Wakui, and Y. Yano:"Nuclear physics experiments with polarized 3Hetarget at RIKEN", Int. Workshop on Polarized
Sources and Targets, (Erlangen University), Erlangen, Germany, Sept. (1999) .
F. Tokanai, K. Morimoto, M. Kurata, 1. Tanihata, andS. Yamada: "Development of time-of-flight detector with streak camera" , 1999 IEEE Nuclear Science
Symp. and Medical Imaging Conf., Seattle, USA,
Oct. (1999).
T. Uesaka, H. Sakai, H. Okamura, J . Tamii, Y.
Satou, T. Ohnishi, N. Sakamoto, T. Wakasa, K.
Itoh, K. Sekiguchi, K. Yako, S. Sakoda, and K.
Suda: "3He(d,p)4He reaction at intermediate energies", RCNP-TMU Symp. on Spins in Nuclear andHadronic Reactions, (Research Center for Nuclear
Physics, Osaka University, and Tokyo Metropolitan
University), Tokyo, Oct. (1999).
K. Sumiyoshi, H. Shen, K. Oyamatsu, Y. Sugahara,
M. Terasawa, K. Otsuki , H. Suzuki, S. Yamada, T.
Kajino, H. Toki , and 1. Tanihata: "Unstable nuclei
and EOS for supernova and r-process" , RCNP-TMU
Symp. on Spins in Nuclear and Hadronic Reactions ,(Research Center for Nuclear Physics, Osaka University, and Tokyo Metropolitan University), Tokyo,
Oct. (1999).
H. Madokoro, M. Matsuzaki, and M. Matsuzaki:"Largely deformed states in nuclei close to the N=Z
line" , YITP Workshop on Structure and Reaction of
Unstable Nuclei, (Yukawa Institute for Theoretical
Physics , Kyoto University) , Kyoto , Nov. (1999).
K. Sumiyoshi: "Unstable nuclei and EOS table forsupernova and r-process simulations in relativistic
many body approach", YITP Workshop on Structure and Reaction of Unstable Nuclei, (Yukawa Institute for Theoretical Physics, Kyoto University),
Kyoto, Nov. (1999).
H. Madokoro, J. Meng, M. Matsuzaki, and S. Yamaji:"Shears bands in the A=80 region", Ganmasen Kakubunkou to Tanjumyoukaku no Furontia,(JAERI), Tokai-mura, Dec. (1999).
K. Naito, T. Umekawa, and M. Oka: "Study of thermal system using the non-perturbative renormalization group" , KEK Tanashi Kenkyuukai on QCD and
Hadron Physics , Tanashi, Dec. (1999).
T. Suzuki: "Effects of the Dirac sea on nuclear responses" , New Developement of the Field Theory for
Many-Body System, (Yukawa Institute for Theoretical Physics , Kyoto University), Kyoto, Dec. (1999).
T. Uesaka: "Study of the short-range structure of lightnuclei via the nucleon transfer reactions at intermediate energies", RCNP Workshop on TARN-II,(Research Center for Nuclear Physics, Osaka University) , Osaka, Dec. (1999).
T. Suzuki: "A few topics on giant resonance states",

RIKEN Int. Symp. on Quasiparticle and Phonon
Excitations in Nuclei, Wako, Dec. (1999).

3.

Atomic and solid-state physics

I. Shimamura: "Hyperspherical close-coupling calculations on the dynamics of three-body systems", Int.
Lectures on Atomic and Molecular Physics, Asia Pacific Center for Theoretical Physics (APCTP), Seoul,
Korea, Apr. (1998).
Y. Morishita, S. Ninomiya, Y. Yamazaki, K. Kuroki,
K. Komaki, H. Masuda, and M. Sekiguchi: "Visible
light emission from slow highly charged ions interacting with micro capillaries", 23rd Ann. Meet. ofSociety for Ato~ic Collision Research, Yokohama,Aug. (1998).
N. Okabayashi, K. Kuroki, T. Azuma, K. Komaki, H.
Masuda, and M. Sekiguchi: "Two dimensional velocity distribution of hydrogen ions potential-sputteredby highly charged ions", 23rd Ann. Meet. of Society for Atomic Collision Research, Yokohama, Aug.
(1998) .
A. Fukaya, I. Watanabe, M. Hagiwara, and
K. Nagamine:"Muon spin resonance of the
Haldane-gap systems NENP and NiC 2 0 4 2(2methylimidazole)" , 1998 Fall Meet. of Physical Society of Japan, Okinawa, Sept. (1998).
A. Koyama: "Auger electron spectra induced by heavy
ion impact", 15th Int. Conf. on the Application of
Accelerators in Research and Industry, (Universityof North Texas), Denton, USA , Nov. (1998) .
T. Kambara: "Atomic physics experiments at RIKEN
Accelerators" , Busshitsu Kagaku Symp. on Tandem
Ryouiki no Jyuuion Kagaku Kenkyuukai, (Japan
Atomic Energy Research Institute), Mito, Jan.
(1999).
I. Shimamura: "Photon-impact emission of an electronfrom two-electron atoms and collision processes involving muonic hydrogen atoms", Workshop on Hyperspherical Harmonic Methods in Atomic, Molecular, and Nuclear Physics, (University of Washington) , Seattle, USA, Jan. (1999) .
T . Nishimura: "Elastic scattering of positrons fromrare gases and simple polyatomic molecules", Genshibutsurigaku Seminaa, (The Institute of Space andAstronautical Science) , Sagamihara, Feb. (1999).
T. Kambara: "Acoustic emission from heavy-ion irradiation on solids", RIKEN Symp. on Studies on
Condensed Matter Physics , Atomic Physics, Nuclear
Chemistry, and Biomedical Science Using RIKEN
Accelerators , Wako, Feb. (1999).
Y. Nakai: "Ionization and dissociation of fullerene byfast heavy ion impact" , RIKEN Symp. on Studies on
Condensed Matter Physics , Atomic Physics, Nuclear
Chemistry, and Biomedical Science Using RIKEN
Accelerators, Wako, Feb. (1999).
N. Ishikawa, A. Iwase, Y. Chimi, N. Kuroda, K. Tsuru,
O. Michikami , H. Wakana, and T. Kambara: "De-feet production through electronic excitation in oxide
superconductors irradiated with swift heavy ions",
54th Ann. Meet. of Physical Society of Japan, Higashihiroshima, Mar . (1999) .
Y. Kanai, T . Kamei, K. Ogura, T. Takayanagi, K.
Wakiya, and Y. Nakai: "Angular distribution ofAuger electrons from doubly-excited states producedby highly-charged ion-atom collisions", 54th Ann.
Meet. of Physical Society of Japan, Higashihiroshima, Mar. (1999).
Y. Morishita, Y. Yamazaki, K. Kuroki, H. Torii, K.
Komaki, H. Masuda, and M. Sekiguchi: "Visible
light emission from slow highly charged ions transmitted through Ni microcapillary(2)", 54th Ann.
Meet. of Physical Society of Japan, Higashihiroshima, Mar. (1999).
Y. Iwai, S. Thuriez , R. Hutton, Y. Kanai, H. Oyama,
H. Masuda, T. Azuma, K. Ando, K. Komaki, and Y.
Yamazaki: "Study of hollow atom with high resolution soft X-ray spectrometer", 54th Ann. Meet. ofPhysical Society of Japan, Higashihiroshima, Mar.
(1999).
Y. Nakai, T. Kambara, A. Itoh, H. Tsuchida, and Y.
Yamazaki: "Ionization and fragmentation of C 60 byfast ion impact in MeV region-TOF spectrum profile
II", 54th Ann. Meet. of Physical Society of Japan,
Higashihiroshima, Mar. (1999) .
T. Nishimura and I. Shimamura: "Elastic scattering of
positrons from Ar atoms and CH 4 molecules", 54th
Ann. Meet. of Physical Society of Japan, Higashihiroshima, Mar. (1999).
J. Wang, T . Saito, M. Takahashi, T . Shishido, T .
Fukuda, E. Vagi, M. Takeda, and J. Wang: "Measurement of 155Ga Mossbauer spectra", 76th National Meet. of the Chemical Society of Japan, Yokohama, Mar. (1999).
T. Nishimura:"Elastic scattering of positrons
from rare gaseous atoms and simple polyatomic
molecules", Seminars for Theory of Atomic/
Molecular Processes, Tokyo, Mar. (1999).
T. Kambara: "Heavy ion accelerators and atomic
physics", 6th Genshi Shototsu Kenkyu Kyokai Seminaa, Wako, Apr. (1999).
T. Nishimura:"Theoretical study for positronmolecule collisions", Kisobutsurigaku Kenkyuujo
Kenkyuukai, (Yukawa Institute for Theoretical
Physics, Kyoto University), Kyoto, May (1999).
J. Kim, F. Saito, Y. Nagashima, A. Goto, Y. Itoh, andT. Hyodo: "Design of an electrostatic positron beam
for spin state study" , 6th Int. Workshop on Positronand Positronium Chemistry, Tsukuba, June (1999) .
E. Vagi, T. Urai, and S. Koike: "The state of hydrogen in Nb-Mo alloys as observed by a channelling
method", 14th Int. Conf. on Ion Beam Analysis, (Forschungszentrum Rossendorf, Institute of Ion
Beam Physics and Materials Research), Dresden,
Germany, July (1999).
E. Vagi, T. Sasahara, T. Joh, T. Urai, T. Sasamoto, N.
283

Tajima, T . Watanabe, and S. T . Nakagawa: "Channelling studies on the Xe bubble formation in Xeimplanted Fe", 14th Int. Conf. on Ion Beam Analysis, (Forschungszentrum Rossendorf, Instite of Ion
Beam Physics and Materials Research), Dresden,
Germany, July (1999).
R. Hutton, S. Thuriez, Y. Iwai, Y. Kanai, H. Oyama,
H. Masuda, and Y. Yamazaki: ~~Cascade filling of
hollow atoms produced with micro-capillary targets", 21st Int . Conf. on the Physics of Electronicand Atomic Collisions (XXI-ICPEAC), (Society for
Atomic Collision Research, Japan, Physical Societyof Japan, and Chemical Society of Japan), Sendai,
July (1999).
S. Thuriez, Y. Iwai , Y. Kanai, H. Oyama, R. Hutton ,H. Masuda, and Y. Yamazaki: "High-resolution
studies of light hollow atoms created using a microcapillary target", 21st Int. Conf. on the Physics
of Electronic and Atomic Collisions (XXI-ICPEAC),(Society for Atomic Collision Research, Japan, Physical Society of Japan, and Chemical Society ofJapan), Sendai, July (1999).
S. Uramoto, I. Shimamura, and H. Sato: "Superexcited states of the hydrogen molecule lying below
the third ionization limit", 21st Int. Conf. on the
Physics of Electronic and Atomic Collisions (XXIICPEAC), (Society for Atomic Collision Research,
Japan, Physical Society of Japan, and Chemical Society of Japan), Sendai, July (1999).
M. Kimura and I. Shimamura: "Vibrational excitation of CO molecule adsorbed on Ag surfaces", 21stInt. Conf. on the Physics of Electronic and Atomic
Collisions (XXI-ICPEAC), (Society for Atomic Collision Research , Japan, Physical Society of Japan, andChemical Society of Japan), Sendai, July (1999).
A. Iwase, Y. Chimi, N. Ishikawa, and T. Kambara:"Atomic displacements induced by high density electronic excitation in iron", 21st Int. Conf. on the
Physics of Electronic and Atomic Collisions (XXIICPEAC), (Society for Atomic Collision Research,
Japan, Physical Society of Japan, and Chemical Society of Japan) , Sendai, July (1999).
X. P. Xie, W. Sun, W. Huang, P. Xue, C. B. Xu,
X. Xu, J .-2. Tang, and I. Shimamura: "Photoionization of He up to the threshold of production of
He+ (N=10): Hyperspherical close-coupling calculations", 21st Int. Conf. on the Physics of Electronicand Atomic Collisions (XXI-ICPEAC), (Society for
Atomic Collision Research, Japan , Physical Societyof Japan , and Chemical Society of Japan), Sendai,
July (1999).
T. Watanabe , X.-M. Tong, S. Ohtani, K. Iemura, Y.
Kanai, and H. Suzuki: "Mechanism of doubly excited He by double electron transfer from neutral
atoms", 21st Int. Conf. on the Physics of Electronicand Atomic Collisions (XXI-ICPEAC), (Society for
Atomic Collision Research, Japan, Physical Societyof Japan, and Chemical Society of Japan), Sendai,
284

July (1999).
Y. Kanai: "Production of doubly-excited He-atoms incollisions of He 2 + -ions with alkaline-earth atoms",
21st Int.
Conf.
on the Physics of Electronicand Atomic Collisions (XXI-ICPEAC), (Society for
Atomic Collision Research, Japan, Physical Societyof Japan, and Chemical Society of Japan), Sendai,
July (1999) .
Y. Nakai, T. Kambara, A. Itoh, H. Tsuchida, andY. Yamazaki: "Time-of-flight profile of fullerene-likefragment ions in fast He 2 + -C 60 collision", 21st Int.
Conf. on the Physics of Electronic and Atomic Collisions (XXI-ICPEAC), (Society for Atomic Collision Research , Japan, Physical Society of Japan, andChemical Society of Japan), Sendai, July (1999).
Y. Nakai, T. Kambara, A. Itoh, H. Tsuchida, and Y.
Yamazaki: "Asymmetric fission of multiply charged
C 60 ion by fast C 6 + impact", 21st Int. Conf. on the
Physics of Electronic and Atomic Collisions (XXIICPEAC) , (Society for Atomic Collision Research,
Japan, Physical Society of Japan, and Chemical Society of Japan), Sendai, July (1999).
R. J. Whitehead, I. Shimamura, and J. F. MaCann:"Protonium formation in p-H collisions", 21st Int.
Conf. on the Physics of Electronic and Atomic Collisions (XXI-ICPEAC), (Society for Atomic Collision Research, Japan, Physical Society of Japan , andChemical Society of Japan), Sendai, July (1999).
I. Shimamura, M. Kimura, and G. Ya. Korenman:"Formation of metastable antiprotonic lithium" ,21stInt. Conf. on the Physics of Electronic and Atomic
Collisions (XXI-ICPEAC), (Society for Atomic Collision Research, Japan , Physical Society of Japan, andChemical Society of Japan), Sendai, July (1999).
S. Kitazawa, M. Sataka, H. Tawara, M. Imai , H.
Shibata, K. Komaki, K. Kawatsura, and Y. Kanai:"Ejected electron spectra from high energy highly
charged oxygen ions in collisions with atoms", 21stInt. Conf. on the Physics of Electronic and Atomic
Collisions (XXI-ICPEAC), (Society for Atomic Collision Research, Japan , Physical Society of Japan, andChemical Society of Japan), Sendai, July (1999).
K . Ogura, M. Okamoto, T. Takayanagi, K. Wakiya,
Y. Nakai , and Y. Kanai: "A toroidal-type electronenergy analyzer for ion-atom collisions", 21st Int.
Conf. on the Physics of Electronic and Atomic Collisions (XXI-ICPEAC), (Society for Atomic Collision Research, Japan , Physical Society of Japan, andChemical Society of Japan) , Sendai, July (1999).
M. Kitajima, Y. Nakai, Y. Kanai, M. Hoshino, Y.
Yamazaki , and Y. Itoh: "The angular dependenceof the scattering intensity in double electron capture of C 4 + - He at the collisional energy of 116.8
eV /q", 21st Int. Conf. on the Physics of Electronicand Atomic Collisions (XXI-ICPEAC), (Society for
Atomic Collision Research, Japan, Physical Societyof Japan, and Chemical Society of Japan), Sendai,
July (1999).

T. Nishimura and 1. Shimamura:"Low-energy
positron collisions with methane molecules and argon
atoms", 21st Int. Conf. on the Physics of Electronicand Atomic Collisions (XXI-ICPEAC), (Society for
Atomic Collision Research, Japan , Physical Societyof Japan, and Chemical Society of Japan), Sendai,
July (1999).
E. Yagi: "Investigation of the state of hydrogen in crystals by the nuclear-reaction channelling method",Japan Institute of Metals Seminar on the Up-to-date
Methods for Hydrogen Detection and the Preventive
Measures for the Hydrogen Embrittlement, Tokyo ,July (1999).
1. Shimamura:"Atomic three-body dynamics",
RIKEN Symp. on the Theory of Atomic and Molecular Processes, Wako, July (1999).
T. Nishimura: "Positron scattering by polyatomic
molecules" , RIKEN Symp. on the Theory of Atomic
and Molecular Processes, Wako, July (1999).
Y. Yamazaki: "Trapping, cooling and extraction of antiprotons, and the ASACUSA project", 1999 Workshop on Nonneutral Plasmas, (Princeton University), Princeton, USA, Aug. (1999).
N. Kuroda, N. Ishikawa, Y. Chimi, A. Iwase, S.
Okayasu, H. Ikeda, R. Yoshizaki, and T. Kambara:"Effect of damage morphology on the pinning andvortex dynamics in Bi2Sr2CaCu208+<5 irradiatedwith GeV heavy-ions", 22nd Int. Conf. on Low Temperature Physics, (Low Temperature Laboratory,
Helsinki University of Technology), Espoo, Helsinki,
Finland, Aug. (1999).
Y. Yamazaki: "Atomic physics and related field withRIKEN MUSES", CCAST-WL Workshop Series:
Vol.IOI on New Atomic Physics Opportunities at
HIRFL-CSR, (Institute of Modern Physics , Chinese
Academy of Sciences), Beijing, China, Aug. (1999) .
Y. Chimi, A. Iwase, N. Ishikawa, N. Kuroda, and T.
Kambara: "Radiation annealing induced by electronic excitation in iron" ,Int. Conf. on Atomic Collisions in Solids (ICACS-18), (Physics Department ,Odense University), Odense, Denmark, Aug. (1999).
T. Kambara, T. M. Kojima, Y. Kanai, Y. Nakai, A.
Yoneda, K. Kageyama, and Y. Yamazaki: "Acoustic emission from heavy-ion irradiation", Int . Conf.
on Atomic Collisions in Solids (ICACS-18), (Physics
Department, Odense University), Odense, Denmark,Aug. (1999).
A. Fukaya, 1. Watanabe, S. Ohira, and K.
Nagamine: "Muon spin resonance of Haldane-gap
systems, Ni(C2HsN2)2N02(CI04) and NiC 20 4 2·(2methylimidazole)" , 8th Int. Conf. on Muon Spin
Rotation , Relaxation and Resonance, (Paul Scherrer Institut , EPS , Universitas Turicensis, ETH) , Les
Diablerets, Switzerland , Aug. (1999).
A. Fukaya, W. Higemoto, M. Hagiwara, and K.
Nagamine: "p'sR study of a spin ladder system(Cul_xZnxh(1,4-diazacycloheptane)2CI4", 8th Int.
Conf. on Muon Spin Rotation, Relaxation and Res-

onance, (Paul Scherrer Institut, EPS, Universitas
Turicensis , ETH), Les Diablerets, Switzerland, Aug.
(1999).
Y. Yamazaki: "Atomic spectroscopy and collisions using slow antiprotons", 18th Int. Conf. on X-ray
and Inner-Shell Processes, (Argonne National Laboratory), Chicago, USA, Aug. (1999).
1. Shimamura: "Application of the hyperspherical coordinate method to atomic processes", Int. Symp.
on Atomic Physics (ISAP99) , Hanoi, Vietnam, Aug.
(1999).
Y. Chimi, A. Iwase, N. Ishikawa, N. Kuroda, and T.
Kambara: "Electronic excitation and atomic displacements induced by high-energy heavy ion irradiation in Fe(II)", 1999 Fall Meet. of Physical Societyof Japan, Morioka, Sept. (1999).
E. Yagi, T. Sasahara, T. Joh, M. Hacke, T. Urai,
T. Sasamoto, N. Tajima, T. Watanabe, and S. T.
Nakagawa: "Investigation of the bubble formation
process in Xe-implanted Fe by means of the channelling method", 1999 Fall Meet. of Physical Societyof Japan, Morioka, Sept. (1999).
Y. Yoshida, Y. Kobayashi, A. Yoshida, F. Ambe, Y.
Yano, and F. Shimura: "Studies on jump process
and lattice position in Si of 57Mn/57Fe atoms prod uced by projectile-fragmentation reaction", 1999
Fall Meet. of Physical Society of Japan, Morioka,
Sept. (1999).
H. Matsushima, Y. Yamazaki, Y. Nakai, A. Hitachi, N.
Kiyoto, T . Hosobuchi, N. Kouchi, and Y. Morishita:"Quenching of long decay components in plastic scintillators", 42nd Symp. on Radiation Chemistry, Hiroshima, Sept. (1999) .
M. Matsuda, K. Katsumata, R. S. Eccleston, S.
Brehmer, and H.-J. Mikeska: "Magnetic excitations
from the 5=1/2 two-leg ladders in La6Ca8Cu24041 ",44th Ann. Conf. on Magnetism and Magnetic Materials, (American Institute of Physics), San Jose,
USA, Nov. (1999).
E. Yagi: "Observation of lattice locations of hydrogendissolved in alloys by means of the nuclear reaction
channelling method", 138th Fall Meet. of Ion andSteel Institute of Japan, Kanazawa, Nov. (1999).
T. Maruyama, H. Yamada, T. Mochizuki, K. Akimoto,and E. Yagi: "Luminescence quenching mechanism
in Sm doped ZnS" , 9th Int.
Conf.
on II-VI
Compounds(II-VI '99), (Japan Society for the Promotion of Science), Kyoto, Nov. (1999).
Y. Nakai and T. Kambara: "Application of STJ
for molecular-, atomic-physics and ion irradiation",
RIKEN Symp. on Application of Superconductor
Radiation Detectors, ST J Workshop, Wako, Dec.
(1999) .
Y. Yamazaki: "Summary of beam microcapillary spectroscopy", RIKEN Symp. on Production of Ultra Slow Highly-Charged Ions and Its Application,
Wako, Dec. (1999).
Y. Iwai: "Soft X-ray spectroscopy of slow highly285charged ions through micro capillary" , RIKEN
Symp. on Production of Ultra Slow Highly-Charged
Ions and Its Application, Wako, Dec. (1999).
M. Wada: "Slow or trapped RI-beams from projectile
fragment separators and their laser", RIKEN Symp.
on Production of Ultra Slow Highly-Charged Ionsand Its Application, Wako, Dec. (1999).
Y. Kanai: "Slow HCI production and facility at
Atomic Physics Lab.", RIKEN Symp. on Production of Ultra Slow Highly-Charged Ions and Its Application, Wako, Dec. (1999).
N. Oshima: "Development of a new positron accumulator using an electron cooling technique", RIKEN
Symp. on Production of Ultra Slow Highly-Charged
Ions and Its Application, Wako, Dec. (1999).
T. M. Kojima: "MCI cooling with cold positrons ina penning-malmberg trap", RIKEN Symp. on Production of Ultra Slow Highly-Charged Ions and Its
Application, Wako, Dec. (1999).
Y. Nakai: "Plan of multiple ionization experiment of
neutral atom with ultra fast TW-Iaser in RIKEN",
RIKEN Symp. on Production of Ultra Slow HighlyCharged Ions and Its Application, Wako, Dec.
(1999).
Y. Yamazaki: "Phase II research with slow highly
charged ions", RIKEN Symp. on Production of Ultra Slow Highly-Charged Ions and Its Application,
Wako, Dec. (1999).

4.

Radiochemistry, radiation chemistry, and radiation biology

Y. Einaga, O. Sato, T. Iyoda, Y. Kobayashi, F. Ambe,
K. Hashimoto, A. Fujishima, and K. Hashimoto:"Characterization of cobalt-iron cyanide by 57Fe
Mossbauer spectroscopy", Proc. Specialist Research
Meet. on Solid State Physics with Probes of Radiations and Nuclei, (Research Reactor Institute, Kyoto
University), Kumatori, Nov. (1997).
Y. Kobayashi, Y. Yoshida, A. Yoshida, Y. Watanabe,
N. Aoi, K. Hayakawa, K. Yukihira, J. Nakamura,
S. Nasu, and F. Ambe: "In-beam Mossbauer spectroscopy for materials science at RIKEN Accelerator Research Facility", Specialist Research Meet. on
Solid State Physics with Probes of Radiations andNuclei, (Research Reactor Institute, Kyoto University), Kumatori, Nov. (1997).
T. Abe, H. Takahashi, S. Kumada, C. H. Bae,T. Matsuyama, and S. Yoshida: "Effective plantmutation method using heavy-ion beams", Ann.
Meet. of Japan Society for Bioscience, Biotechnology, and Agrochemistry, Nagoya, Mar. (1998).
S. Enomoto, R. Hirunuma, T. Ozaki, S. Ambe, and
F. Ambe: "Dynamics of various trace elements in
Se-deficient rats", 2nd Int. Symp. on Metals andGenetics, Toronto, Canada, May (1998).
R. Amano, S. Oishi, S. Enomoto, and F. Ambe: "Aging effects on regional cerebral uptakes and concen286

trations of some trace elements in normal mice",
2nd Int. Symp. on Metals and Genetics, Toronto,
Canada, May (1998).
S. Enomoto, R. Hirunuma, J. Chou, S. Ambe, and F.
Ambe: "Transfers of trace elements from the placenta to the rat fetus", 42nd Symp. on Radiochemistry, Sendai, Sept. (1998).
S. Enomoto and F. Ambe: "The multitracer techniquein bio-trace element research", Int. Conf. on Nuclear
Analytical Methods in the Life Sciences (NAMLS),(China Institute of Atomic Energy), Beijing, China,
Oct. (1998).
S. Sharma, K. Kimura, and J. Kaneko: "New 100
ps-lived luminescence from ion-irradiated RbI" ,41stSymp. on Radiation Chemistry, (Japanese Societyof Radiation Chemistry), Kobe, Oct. (1998).
T . Abe: "Biological effects of heavy-ion beam onplants", 8th Chromosome Colloq., Tsukuba, Nov.
(1998).
S. Kitayama, 1. Narumi, M. Kikuchi, K. Sato, T.
Funayama, and H. Watanabe: "uvrC gene and its
mutation in Deinococcus radiodurans" , 41st Ann.
Meet. of Japan Radiation Research Society, N agasaki, Dec. (1998).
K. Satoh, 1. Narumi, M. Kikuchi, T. Funayama,
T. Yanagisawa, S. Kitayama, and H. Watanabe:"Cloning of recA gene of a radioresistant bacterium,
Deinococcus radiodurans and its expression in E.
coli.", 41st Ann. Meet. of Japan Radiation ResearchSociety, Nagasaki, Dec. (1998).
T. Funayama, 1. Narumi, K. Satoh, O. Kou, S.
Kitayama, H. Watanabe, and K. Yamamoto: "DNArepair gene deletion mutants of radioresistant bacteria by the insertion of drug-resistant gene cassette" ,41st Ann. Meet. of Japan Radiation Research Society, Nagasaki, Dec. (1998).
S. Kitayama, 1. Narumi, M. Kikuchi, K. Sato, T.
Funayama, H. Watanabe, and K. Sato:"Nucleotide excision repair in a radioresistant bacterium,
Deinococcus radiodurans" , 21st Ann. Meet. ofJapanese Society of Molecular Biology, Yokohama,Dec. (1998).
R. Amano, S. Oishi, and S. Enomoto: "Regional uptake behaviors of radioactive Rb, Zn, Se, Mn, Sc
and Zr tracers in brain of young and aged C57BL/6N
mice" ,5th Internet World Congr. on Biomedical Science '98, (McMaster University), Hamilton, Canada,Dec. (1998).
S. Enomoto: "Distribution of vanadium in various disease animals", Symp. on Vanadium, (Kyoto Pharmaceutical University), Kyoto, Dec. (1998) .
S. Sharma and J. Kaneko: "Extremely short livedluminescence components in ionic crystals excited athigh density by heavy-ion irradiation", 54th Ann.
Meet. of Physical Society of Japan, Hiroshima, Jan.
(1999).
K. Ushida, K. Ishioka, and M. Kitajima: "Coherent phonon spectroscopy applied to the surface

modification by ion beams", 22nd Hyomen-Kagaku
Kenkyukai, Tsukuba, Feb. (1999).
C. H. Bae, T. Abe, T. Nakano, T. lVlatsuyama, N.
Nagata, and S. Yoshida: "A novel albino mutant,alth deficient in chloroplast gene expression", 1999
Ann. Meet. of Japanese Society of Plant Physiologists, Sendai, Mar. (1999).
C. H. Bae, T. Abe, T. Nakano, T. Matsuyama, N.
Nagata, and S. Yoshida: "A novel albino mutant,alth deficient in chloroplast gene expression", Ann.
Meet. of Japan Society for Bioscience, Biotechnology, and Agrochemistry, Fukuoka, Mar. (1999).
H. Takahashi, T. Abe, K. Sekino, C. H. Bae, T. Andoh,
and S. Yoshida: "Effect of clomazone on carotenogenesis of tobacco", 24th Ann. Meet. of Pesticide
Science Society of Japan, Utsunomiya, Mar. (1999).
F. Saito, J. Kim, Y. Itoh, A. Goto, 1. Fujiwara, T.
Kurihara, N. Suzuki, Y. Nagashima, and T. Hyodo:"Development of intense 18F positron source electrodeposited on graphite", 54th Ann. Meet. of PhysicalSociety of Japan, Higashihiroshima, Mar. (1999).
R. Hirunuma, S. Enomoto, and K. Endo: "Behavior ofradioactive trace elements in Se-deficient rats using
the multitracer technique", 119th Ann. Meet. of thePharmaceutical Society of Japan , Tokushima, Mar.
(1999) .
T. Yanagiya, S. Himeno, N. Imura, Y. Kondo, R.
Hirunuma, and S. Enomoto: "Alteration in metaltransport in cadmium-resistant metallothionein nullcells", 119th Ann. Meet. of the Pharmaceutical Society of Japan, Tokushima, Mar. (1999).
R. Hirunuma, S. Enomoto, K. Endo, S. Ambe, and
F. Ambe: "Behavior of multitracer in Se-deficientrats", RIKEN Symp. on Bio-Trace Elements '99,
Wako, Mar. (1999).
K. Matsumoto, K. Endo, R. Hirunuma, S. Enomoto,
S. Ambe, and F. Ambe: "Distribution of various elements in cell fraction of liver of Se-deficient rats",
RIKEN Symp. on Bio-Trace Elements '99, Wako,
Mar. (1999).
T. Oyama, T. Yoshida, M. Iwama, M. Yanaga, S.
Enomoto, R. Hirunuma, M. Noguchi, and T. Omori:"U ptake of various elements in Zn-deficient mice",
RIKEN Symp. on Bio-Trace Elements '99, Wako,
Mar. (1999).
H. Suzuki, H. Kumagaya, K. Oohashi, K. Sakamoto,
K. Inubushi, S. Enomoto, and F. Ambe: "Uptake of various elements into Arbuscular Mycorrhizal
Marigold", RIKEN Symp. on Bio-Trace Elements'99, Wako, Mar. (1999).
T. Yanagiya, S. Himeno, N. Imura, Y. Kondo, R.
Hirunuma, and S. Enomoto: "Study on metaltransport pathway using cadmium-resistant metallo
thionein null fibroblasts", RIKEN Symp. on BioTrace Elements '99, Wako, Mar. (1999).
T. Ozaki, S. Enomoto, Y. Minai, and Y. Makide:"Study on the uptake mechanism and behavior ofrare earth elements in plants", RIKEN Symp. on

Bio-Trace Elements '99, Wako, Mar. (1999).
M. Kusakabe, T. Tsukada, N. Hiraiwa, C. Poirier,
F. Ike, Y. Yoda, N. Fukunishi, M. Kase, Y. Yano,and A. Yoshiki: "Heavy ion beams: An application
to mouse mutagenesis", 32nd Ann. Meet. of theJapanese Society of Developmental Biologists, Kobe,
May (1999).
R. Hirunuma, S. Enomoto, S. Ambe, and F. Ambe:"Distribution of selenium, arsenic, iron, and scandiumin selenium-deficient rats using the multitracer
technique", 10th Int. Symp. on Trace Elements
in Man and Animal, (Joseph Fourier University) ,Evian, France, May (1999).
S. Enomoto, R. Hirunuma, T. Ozaki, S. Ambe, and
F. Ambe: "Transfers of trace elements from the placenta to the fetus of pregnant rat by using the multitracer technique", 10th Int. Symp. on Trace Elements in Man and Animal, (Joseph Fourier University), Evi;:m, France, May (1999).
R. Hirunuma, S. Enomoto, F. Ambe, and H. Sakurai:"Behavior of trace elements in Se-deficient rats",
16th Symp. on Trace Nutrients Research, Kyoto,
May (1999).
F. Yatagai, A. Gordon, S. Morimoto, N. Fukunishi,
M. Honma, T. Sofuni, and F. Hanaoka: "Hprt mutation induction in human cells by heavy-ion irradiation", 10th Ann. Space Radiation Health Investigator's Workshop, (NASA), New York, USA, June
(1999) .
F. Saito, Y. Itoh, A. Goto, 1. Fujiwara, T. Kurihara,
N. Suzuki, Y. Nagashima, and T. Hyodo: "Preparation of 18F source for slow positron beam by proton
bombardment of 180-water", 6th Int. Workshop on
Positron and Positronium Chemistry, Tsukuba, June
(1999).
M. Takahashi, K. Sasaki, and S. Enomoto: "Metal uptake by a transgenic tabacco with Mdip 1 gene that isexpressed in Mn-depleted tomato root" , Ann. Meet.
of Japanese Society of Soil Science and Plant Nutrition, Sapporo, July (1999).
H. Suzuki, H. Kumagaya, K. Oohashi, K. Sakamoto,
K. Inubushi, S. Enomoto, and F. Ambe: "Analysis of the uptake of trace elements in arbuscularmycorrhizal plant using multitracer technique (1) ",Ann. Meet. of Japanese Society of Soil Science andPlant Nutrition, Sapporo, July (1999).
F. Saito, N. Suzuki, Y. Itoh, A. Goto, I. Fujiwara, T.
Kurihara, Y. Nagashima, and T. Hyodo: ,, 18 F for
positron beam source produced by AVF cyclotron",36th Ann. Meet. on Radioisotopes in the PhysicalScience and Industries, (Japan Radioisotope Association), Tokyo, July (1999) .
F. Saito, N. Suzuki, Y. Itoh, A. Goto, I. Fujiwara, T.
Kurihara, Y. Nagashima, and T. Hyodo: "Development of intense 18F source for slow positron beamby AVF cyclotron", 21st Int. Conf. on the Physics
of Electronic and Atomic Collisions (XXI-ICPEAC) ,Sendai, July (1999).
287

Y. Furusawa, M. Saitou, T. Kanai, F. Yatagai, M.
E. Vazguez, and T. C. Yang: "LET-RBE spectra
for cell survival upon V79 cells exposed to accelerated silicon-, argon-, and iron-ion beams", lIth Int.
Congr. of Radiation Research, Dublin, Ireland, July
(1999).
F. Yatagai, A. Gordon, S. Morimoto, N. Fukunishi, M.
Honma, T. Sofuni, and F. Hanaoka: "Nature of hprt
mutations induced by heavy-ion irradiation", lIth
Int. Congr. of Radiation Research, Dublin, Ireland,
July (1999).
F . Saito, N. Suzuki, Y. Itoh, A. Goto, 1. Fujiwara, T.
Kurihara, Y. Nagashima, and T. Hyodo: "Development of intense 18F source for slow positron beam",
10th Workshop on Low-Energy Positron and Positronium Physics, Tsukuba, July (1999).
Y. Kobayashi: "Experiments of 106 Sg element withlong half-life in Dubna (Russia)", Workshop on Nuclear Science of Heavy Elements, (Japan Atomic Energy Research Institute), Tokaimura, July (1999).
M. Kusakabe, A. Yoshiki, N. Hiraiwa, T. Tsukada, F.
Ike, C. Poirier, and Y. Yano: "Novel methodology
for mouse mutagenesis by heavy ion irradiation" , Research Meet. on SMXA Mice, (Institute for Laboratory Animal Research, Nagoya University School of
Medicine), Nagoya, Aug. (1999).
K. Ushida, H. Sato, K. Ando, T. Kozawa, and A. Kira:"Instability of dimer radical anion of aromatic hydrocarbons", 1999 Bunshi Kouzou Sougou Touronkai,(Chemical Society of Japan), Osaka, Sept. (1999).
K. Kimura, S. Sharma, and J. Kaneko: "Abnormallyshort lived-luminescence of alkali halides and metaloxides excited using heavy ions", 1999 Fall Meet. ofPhysical Society of Japan, Morioka, Sept. (1999).
K. Kimura, S. Sharma, and J. Kaneko: "Extremely
short lived-luminescence of ion-excited wide-bandgap crystals", 1999 Fall Meet. of Physical Societyof Japan, Morioka, Sept. (1999).
K. Ushida, M. Hase, K. Ishioka, M. Kitajima, andK. G. Nakamura: "Application of coherent phonon
spectroscopy to probing the distribution of latticedisorders", 1999 Fall Meet. of Physical Society ofJapan , Morioka, Sept. (1999).
M. Hase, K. Ishioka, K. Ushida, S. Hishita, and M.
Kitajima: "Dynamical effect of ion irradiation on Bi
crystal lattices by coherent phonon spectroscopy",
1999 Fall Meet.
of Physical Society of Japan,
Morioka, Sept. (1999).
P. Mehnati, F. Yatagai, Y. Kobayashi, F. Hanaoka,
T. Tsuzuki, and H. Sasaki: "Recognition of hit-sites
within the cells exposed to accelerated iron-ions (using CR-39 plastics) ", 42nd Ann. Meet. of Japan Radiation Research Society, Hiroshima, Sept. (1999).
S. Morimoto, G. Alasdair, N. Fukunishi , F. Hanaoka,
and F. Yatagai: "Effect of pre-irradiation by small
dose heavy-ions in human-cells", 42nd Ann. Meet. ofJapan Radiation Research Society, Hiroshima, Sept.
(1999).
288

A. Gordon, S. Morimoto, N. Fukunishi, F. Hanaoka,
and F. Yatagai: "P53 and p21 protein induction in
TK6 and NS human lymphoblastoid cells after Xray and heavy-ion irradiations" , 42nd Ann. Meet. ofJapan Radiation Research Society, Hiroshima, Sept.
(1999).
S. Sharma and J. Kaneko: "New 100 ps lived UV luminescence of ion track in wide band-gap crystals",
42nd Symp. on Radiation Chemistry, (JapaneseSociety of Radiation Chemistry), Higas hihiroshima,
Sept. (1999).
S. Sharma and K. Kimura: "Ion-induced luminescencein alkali iodides: A new 100 ps-lived component",
42nd Symp. on Radiation Chemistry, (JapaneseSociety of Radiation Chemistry), Higashihiroshima,
Sept. (1999).
Y. Yoshida, A. Saeki, T. Kozawa, M. Miki, K. Ushida,
and S. Tagawa: "Study of geminate ion recombination by means of laser-synchronized picosecond andsubpicosecond pulse radiolysis" , 42nd Symp. on Radiation Chemistry, (Japanese Society of Radiation
Chemistry), Higashihiroshima, Sept. (1999).
K. Ushida, H. Sato, K. Ando, T. Kozawa, and A. Kira:"Why does the dimer radical anion of aromatic hydrocarbons not form?", 42nd Symp. on Radiation
Chemistry, (J apanese Society of Radiation Chemistry), Higashihiroshima, Sept. (1999).
M. Hase, K. Ishioka, K. Ushida, and M. Kitajima:"Phonon dynamics in ion-implanted bismuth asprobed by femtosecond laser spectroscopy", 42ndSymp. on Radiation Chemistry, (Japanese Societyof Radiation Chemistry), Higashihiroshima, Sept.
(1999).
S. Morimoto, G. Alasdair, N. Fukunishi, F. Hanaoka,
and F. Yatagai: "Adaptive response in human cultured cells by the heavy-ion irradiation with a small
dose", 13th Ann. Meet. of Japanese Society for Biological Sciences in Space, Tokyo, Sept. (1999).
T. Kitaura, Y. Hara, T. Abe, K. Miyoshi, and S.
Yoshida: "Effect of heavy-ion beam irradiation onshoot elongation in garden roses", 96th Congr. ofBreeding Society of Japan, Okayama, Sept. (1999).
H. Tamano, S. Enomoto, E. Igasaki, N. Oku , N. Itoh ,K. Tanaka, and A. Takeda: "Thmor growth after
subcutaneous transplantation is affected by hepatic
metallothionein leveF' , 2nd Int. Workshop on Metallothionein, (Institute for Reference and Measurements), Geel, Belgium, Oct. (1999).
T. Abe, J.-M. Wang, T. Asami, and S. Yoshida: "Herbicide resistant mutation using heavy-ion beams",
2nd Pan Pacific Conf. on Pesticide Science, (The
Agrochemicals Division of the American Chemical
Society), Honolulu , USA, Oct. (1999).
Y. Kawamura, S. Enomoto, R. Amano, and T. Ozaki:"Synthesis of labeled organometallic chelating agent
using multitracer technique", 43rd Symp. on Radiochemistry, Tsukuba, Oct. (1999).
T. Matsuyama, T. Abe, R. Kiuchi, T. Nakano, T.

Asami, and S. Yoshid a: "RLGS (Restriction Landmark Genomic Scanning) analysis in plant genomes" ,63rd Ann. Meet. of the Botanical Society of Japan ,Akita, Oct. (1999).
H. Takahashi, T. Abe, K. Sekino, T. Andoh, and S.
Yoshida: "Effect of clomazone on carotenogenesis of
tobacco", 34th Ann. Meet. of the Society for theChemical Regulation of Plants, Tottori, Oct. (1999).
A. Yoshiki, N. Hiraiwa, T. Tsukada, Y. Yoda, C.
Poirier, F. Ike, N. Fukunishi, M. Kase, Y. Yano, and
M. Kusakabe: "Heavy ion beams: An application
to mouse mutagenesis", 13th Int. Mouse Genome
Conf. , Philadelphia, USA, Oct. (1999).
T. Tsukada, M. Furutsu, A. Kogiso, H. Yamaguchi, Y.
Kitasaka, M. Kojima, N. Hiraiwa, A. Yoshiki, and M.
K usakabe: "Mouse mutagenesis by heavy ion beams:
Detection of mutant mice by random amplified polymorphic DNA (RAPD)", 13th Int. Mouse Genome
Conf., Philadelphia, USA, Oct. (1999).
F. Yatagai, G. Alasdair, S. Morimoto, T. Mizuno, T.
Kurobe, N. Fukunishi, and F. Hanaoka: "Heavy-ion
exposure effects in human cultured cells and their
response at the molecular level", 22nd Ann. Meet.
of Japanese Society of Molecular Biology, Fukuoka,
Dec. (1999).
M. Yoshimasu, T. Abe, S. Yoshida, T. Inoue , F. Ling,
and T. Shibata: "Analysis of the biological effectsof heavy-ion beam on budding yeast cells", 22nd
Ann. Meet. of Japanese Society of Molecular Biology, Fukuoka, Dec. (1999).
S. Morimoto, G. Alasdair, T. Kurobe, N. Fukunishi,
M. Honma, T. Kato, F. Hanaoka, and F. Yatagai:"Adaptive response in human cultured cells by theheavy-ion irradiation with a small dose", 28th Ann .
Meet. of the Japan Environmental Mutagen Research Society, Gifu, Dec. (1999).
F. Yatagai, G. Alasdair, S. Morimoto, T. Mizuno,
N. Fukunishi, and F. Hanaoka: "Induction of p53
and its related proteins in human cultured cells by
the heavy-ion irradiation", 28th Ann. Meet. of
the Japan Environmental Mutagen Research Society, Gifu , Dec. (1999).
S. Enomoto, R. Amano, and Y. Kawamura: "The Multitracer: Production and application to chemistry
and biology", 16th Int. Symp. on Separation Chemistry, (National Institute for Research in Inorganic
Materials), Tsukuba, Dec. (1999).
K . Ushida, M. Hase, K. Ishioka, and M. Kitajima:"Use of coherent phonon spectroscopy as a probe for
distribution of defects in solids", Int. Workshop on
Molecular Design of Photonic Materials, (Osaka National Research Institute (ONRI), Science and Technology Agency (STA)), Takarazuka, Dec. (1999).
Y. Kawamura, S. Enomoto, and R. Amano: "Synthesis of labeled organometallic chelating agent using
multitracer technique" , RIKEN Symp. on Bio-Trace
Elements '99.12 , Wako, Dec. (1999).
T . Soshi, T. Arie, Y. Nose, and I. Yamaguchi: "Influ-

ence of endophyte on radionuclide-uptake by perennial ryegrass", RIKEN Symp. on Bio-Trace Elements '99.12 , Wako, Dec. (1999).
K. Ushida, M. Hase, K. Ishioka, and M. Kitajima:"A new probing method for lattice defects generated by ion beam irradiation: Coherent phonon spectroscopy", 8th Symp. of Research Center for Nuclear
Science and Technology, University of Tokyo, Tokyo,
Dec. (1999).

5.

Material analysis

I. Watanabe, S. Nakajima, K. Nagase, T. Matsuzaki,
K. Ishida, and K. Nagamine: "J1'sR on the magnetically ordered and superconducting states ofTIBa2 Y l-xCaxCU20y", 1996 Fall Meet. of Physical Society of Japan, Yamaguchi, Sept. (1996).
I. Watanabe, N. Wada, H. Yano, A. Yamaguchi, T.
Okuno, K. Awaga, S. Ohira, K. Nishiyama, and K.
N agamine: "Ground state of 2-dimensional organic
magnet, m-MPYNN·BF 4 , observed by J..LSR" , 52nd
Ann. Meet. of Physical Society of Japan, Nagoya,Mar. (1997).
S. Ohira, N. Ishida, T . Nogami, 1. Watanabe, and
K. Nagamine: "J..LSR study on magnetic properties of the organic radical ferromagnet, Ar-CH=NTEMPO", 1997 Fall Meet. of Physical Society ofJapan, Kobe, Oct. (1997).
1. Watanabe, S. Ohira, K. Nagamine, N. Wada, H.
Yano, A. Yamaguchi, and K. Awaga: "J..LSR study
on magnetic properties of the 2-dimensional antiferromagnet, m-MPYNN·BF 4 ", 1997 Fall Meet. ofPhysical Society of Japan, Kobe, Oct. (1997).
Y. Yamamoto, Y. Miyako, K . Nishiyama, I. Watanabe,
and K . Nagamine: "Long-range ordering and spin
fluctuations of Ce(Rul-xRhxhSi2", 1997 Fall Meet.
of Physical Society of Japan, Kobe, Oct. (1997).
I. Watanabe, K. Asai , Y. Kobayashi, N. Yamada, and
K. Nagamine: "Magnetic properties of LaCo0 3 studied by J..L+SR" , 53rd Ann. Meet. of Physical Societyof Japan, Funabashi, Apr. (1998).
S. Ohira, I. Watanabe, K. Nakayama, N. Ishida, T.
Nogami, and K. Nagamine: "J..LSR study of themagnetic properties of the organic ferromagnet , phCH=N-TEMPO", 53rd Ann. Meet. of Physical Society of Japan, Funabashi, Apr. (1998).
J. Arai, T. Ishiguro, M. Ariyama, K. Ozawa, K.
Nakai, 1. Watanabe, and K. Nagamine: "Muon spin
relaxation in (Lal-xSrxhCuo.ggFeo.ol", 53rd Ann.
Meet. of Physical Society of Japan, Funabashi, Apr.
(1998).
M. Akoshima, H. Noji, Y. Ono, Y. Koike, 1. Watanabe,
and K. Nagamine: "Anomalous electronic properties
in Bi2212 phase around53rd Ann. Meet. ofPhysical Society of Japan, Funabashi, Apr. (1998).
K. Hasegawa, K . Maeda, S. Nakayama, A. Tonomura,and H. Hamanaka: "In-air high-resolution PIXE system with a multiwire proportional chamber", 8thprvk",

289

Int. Conf. on PIXE and Its Analytical Applications ,Lund , Sweden , June (1998).
K. Maeda, A. Tonomura, H. Hamanaka, and K.
Hasegawa: "Chemical shift measurements of PIXE
spectra using a position-sensitive crystal spectrometer", 8th Int. Conf. on PIXE and Its Analytical
Applications , Lund , Sweden, June (1998).
M. Akoshima, H. Noji, Y. Ono, Y. Koike, T. Nishizaki,
N. Kobayashi, 1. Watanabe, and K. Nagamine:
problem in Bi- and Y-systems", Dai36kai Choudendou Magunetikusu Kenkyuukai, Tokyo, July (1998).
1. Watanabe, M. Akoshima, Y. Koike, and K.
Nagamine: "Muon-spin relaxation anomaly in Bi2212 system around the hole concentration of1998 Fall Meet. of Physical Society of Japan, Naha,
Sept. (1998).
1. Watanabe, S. Ohira, K. Nagamine, N. Wada, H.
Yano, and K. Awaga: "/-L+SR study on the spin fluctuation of the 2-dimensional organic antiferromagnet, m-MPYNN·BF 4", 1998 Fall Meet. of PhysicalSociety of Japan, Naha, Sept. (1998).
N. Wada, K. Awaga, and 1. Watanabe: "/-LSR and 2dimensional spin-gap state in the Kagome organic
antiferromagnet", 1998 Fall Meet. of Physical Society of Japan, Naha, Sept. (1998).
S. Ohira, Y. Akui, T. Ise, N. Ishida, T. Nogami,
1. Watanabe, and K. Nagamine: "/-LSR study onmagnetic properties of the organic ferromagnet, ArCH=N-TEMPO", 1998 Fall Meet. of Physical Society of Japan, Naha, Sept. (1998).
M. Akoshima, H. Noji, Y. Ono, Y. Koike, T. Nishizaki,
N. Kobayashi, 1. Watanabe, and K. Nagamine:"Anomalous electronic state in the Bi-2212 phaseatII", 1998 Fall Meet. of Physical Society ofJapan, Naha, Sept. (1998).
T. Takabatake, A. Kratzer, 1. Watanabe, D. T.
Adroja, K. Umeo, G. M. Kalvius, and K. Nagamine:"J.lS R study on the spin fluctuations in Ce7Ni3", 1998
Fall Meet. of Physical Society of Japan, Naha, Sept.
(1998).
J. Arai, T. Ishiguro, K. Nakai, 1. Watanabe, and K.
Nagamine: "Muon spin relaxation in La2 -x SrxCu04
around x=k", 1998 Fall Meet. of Physical Society ofJapan, Naha, Sept. (1998).
K. Hasegawa and K. Maeda: "Development of a crystal
spectrometer for PIXE using a multianode PSPC",
Technical Meet. on Nuclear Energy (NE-98), lEE
Japan, Tokyo, Sept. (1998).
M. Akoshima, H. Noji, Y. Koike, T. Nishizaki, N.
Kobayashi, 1. Watanabe, and K. Nagamine: "Supression of the superconductivity around the holeconcentration of
in Bi-2212 and Y-123 phases",
Ouyoubutsurigakkai Touhokushibu Dai53kai Gakujutsukouenkai, Sendai, Dec. (1998).
1. Watanabe, M. Akoshima, Y. Koike, and K.
N agamine: "/-LSR study on the problem of the Bi2212 system", 54th Ann. Meet. of Physical Societyof Japan, Higashihiroshima, Mar. (1999).

"k

k",

prvk

prvk

k

290

J. Arai , T. Ishiguro, K. Nakai, 1. Amamiya, 1.
Watanabe , and K. Nagamine: "Muon spin relaxation of La2- xS rxCU l-yZny04 around x=O.115",
54th Ann. Meet. of Physical Society 6f Japan , Higashihiroshima, Mar. ( 1999) .
M. Akoshima, K. Nishimaki, H. Noji, Y. Koike, 1.
Watanabe, and K. Nagamine: "Anomalous electronic properties in the Bi-2212 phase aroundIII", 54th Ann. Meet. of Physical Society of Japan,
Higashihiroshima, Mar. (1999).
Y. Yamamoto, Y. Miyako, 1. Watanabe, and K.
Nagamine: "/-LSR study on the non-Fermi liquid:Ce(Rul-xRhxhSi2" , 54th Ann. Meet. of PhysicalSociety of Japan , Higashihiroshima, Mar. (1999).
S. Ohira, 1. Watanabe, N. Ishida, T. Nogami, and K.
Nagamine: "/-LSR study on the magnetic propertiesof the organic ferromagnet Ar-CH=N-TEMPO II",
54th Ann. Meet. of Physical Society of Japan, Higashihiroshima, Mar. (1999).
1. Watanabe, N. Wada, K. Awaga, S. Ohira, and K.
Nagamine: "J.lSR study of the quantum spin fluctuation of the ferromagnetic dimer with 5 = 1", 1999
Fall Meet. of Physical Society of Japan, Morioka,
Sept. (1999).
1. Watanabe, N. Wada, K. Awaga, S. Ohira, and K.
N agamine: "/-LSR study on the 2-dimensional organic
antiferromagnet, m-MPYNN·(BF 4,Cl0 4)", 1999 Fall
Meet. of Physical Society of Japan, Morioka, Sept.
(1999).
M. Mekata, K. M. Kojima, H. Ikeda, 1. Watanabe,
and K. Nagamine: "/-LSR on 2-dimensional Ising-spin
antiferromagnet Rb2Col-xMgxF4", 1999 Fall Meet.
of Physical Society of Japan, Morioka, Sept. (1999).
S. Ohira, Y. Akui, T. Katayama, T. Miyake, N.
Ishida, T. Nogami, and K. Nagamine: "/-LSR study
on the organic magnet 4-Pr-CH=N-TEMPO", 1999
Fall Meet. of Physical Society of Japan, Morioka,
Sept. (1999).
T. Ishiguro, H. Shinmen, M. Hirai, J. Arai, 1.
Watanabe, and K. Nagamine: "/-LSR study on
La2-x SrxCUl-yZny04 in an underdoped region" ,1999 Fall Meet.
of Physical Society of Japan ,Morioka, Sept. (1999).
1. Watanabe, M. Akoshima, Y. Koike, S. Ohira, W.
Higemoto, and K. Nagamine: "/-LSR study on the
problem in Bi-, Y- and La-systems", 1999 Fall Meet.
of Physical Society of Japan, Morioka, Sept. (1999).
M. Akoshima, K. Nishimaki, H. Noji, Y. Koike,
1. Watanabe, S. Ohira, W. Higemoto, and K.
Nagamine: "The problem in Bi- , V-systems studies by transport measurements and /-LSR", 1999 Fall
Meet . of Physical Society of Japan, Morioka, Sept.
(1999) .
J. Arai , T. Ishiguro, 1. Watanabe, and K. Nagamine:"The Zn-substituion and the stripe structure inLa2- xSrxCUl-yZny04 studied by /-LSR" , 1999 Fall
Meet. of Physical Society of Japan, Morioka, Sept.
(1999).

prvk

k

k

M. Kidera, T. Nakagawa, K. Takahashi, S. Enomoto,T. Minami, M. Fujimaki, E. Ikezawa, O. Kamigaito,
M. Kase, A. Goto, and Y. Yano: "Measurementsof 26 Al using high-performance ECR ion source plus
heavy ion linac" , 8th Int. Conf. on Accelerator Mass
Spectrometry, (VERA Laboratory, University of Vienna), Vienna, Austria, Sept. (1999).
I. Watanabe, M. Akoshima, Y. Koike, S. Ohira, W.
Higemoto, and K. Nagamine: "~problems in high-Tc
oxides", RIKEN Symp. on Frontiers of Magnetism
Studies with Microscopic Probes: Space-Time Correlation of Spins, Kofu, Oct. (1999).
K. lVlaeda, K. Hasegawa, H. Hamanaka, A. Tonomura,and M. Maeda: "Chemical specification by in-air

high-resolution PIXE" , 3rd Int. Symp. on BioPIXE , (Kyoto University), Kyoto , Nov. (1999).
H. Hamanaka, T. Hasegawa, K. Hasegawa, K. Maeda,
and S. Yumoto: "PIXE analyses of Al compounds
by means of wavelength dispersive spectrometer",
3rd Int. Symp. on Bio-PIXE, (Kyoto University),
Kyoto, Nov. (1999).
H. Hamanaka, T. Hasegawa, K. Hasegawa, K. Maeda,
and S. Yumoto: "Chemical state analysis of Al compounds by crystal spectrometer PIXE (3)", 18th
Symp. on Materials Science and Engineering Research Center of Ion Beam Technology, Hosei U niversity, Koganei, Dec. (1999).

291

x. LIST OF SYMPOSIA(Jan.- Dec. 1999)
1) Symp. on Studies on Condensed Matter Physics, Atomic Physics, Nuclear Chemistry, and Biomedical Science
Using RIKEN Accelerators
2 Feb., Wako , Cellular Physiology Lab., RIKEN
2) RBRC Workshop on Hard Parton Physics in High-Energy Nuclear Collisions
1-5 Mar., New York, USA, RIKEN BNL Research Center3) RBRC Workshop on Event Generator for RHIC Spin Physics
15- 19 Mar., New York, USA, RIKEN BNL Research Center
4) RIKEN Symp. and Workshop on Selected Topics in Nuclear Collective Excitations
20-24 Mar., Wako, Cyclotron Lab., RIKEN
5) RBRC Workshop on Numerical Algorithm at Non-Zero Chemical Potential
27 Apr.-l May, New York, USA, RIKEN BNL Research Center6) RBRC Workshop on Gauge-Invariant Variables in Gauge Theories
27- 29 May, New York, USA, RIKEN BNL Research Center
7) Int. Workshop on Space Factory on JEM/ISS
7- 9 June, Tsukuba, Computational Science Div., Advanced Computing Center, RIKEN
8) RBRC Workshop on OSCAR II: Predictions for RHIC
9- 16 July, New York, USA, RIKEN BNL Research Center
9) Int. Workshop on Atomic Collisions and Atomic Spectroscopy with Slow Antiprotons
19-21 July, Yokohama, Atomic Physics Lab., RIKEN
10) RIKEN Int. Symp. on Models and Theories of the Nuclear Mass
19-23 July, Wako, RIBF Project Office, Cyclotron Center, RIKEN
11) 15th Symp. on Academic Activities for Waste Management
22-23 July, Wako, Safety Center, RIKEN
12) RIKEN Symp. on the Theory of Atomic and Molecular Processes (VII)
31 July-1 Aug. , Wako, Atomic Physics Lab., RIKEN
13) RIKEN Int. Conf. on Astrophysics High T and Low Tau
8- 14 Aug., Sedona, USA, RI Beam Science Lab., RIKEN
14) RBRC Workshop on Coulomb and Pion Asymmetry Polarimetry and Hadronic Spin Dependence at RHIC
Energies
18 Aug., New York, USA, RIKEN BNL Research Center15) 7th RIKEN Workshop for RI-Beam Physics
23 Aug., Wako, RI Beam Science Lab., RIKEN
16) 8th RIKEN Workshop for RI-Beam Physics on Unstable/Hyper Nuclei
2- 3 Sept. , Wako , RI Beam Science Lab., RIKEN
17) RBRC Workshop on RHIC Spin Physics
6- 8 Oct., New York, USA, RIKEN BNL Research Center18) 12th Symp. of Accelerator Science and Technology29227- 29 Oct. , Wako, RIKEN Accelerator Research Facility19) RIKEN Symp. on Frontiers of Magnetism Studies with Microscopic Probes: Space-Time Correlation ofSpins
29- 30 Oct. , Kofu , Muon Science Lab., RIKEN20) RIBF Workshop on Physics on eA collider at MUSES
1- 2 Nov. , Wako , RI Beam Science Lab., RIKEN21) RIKEN Symp. on Large Scale Calculation of Electronic States: Exploring Dynamical Properties of Materials
4-5 Nov. , Wako , Computational Science Div., Advanced Computing Center, RIKEN
22) 9th RIKEN Workshop for RI-Beam Physics
23-24 Nov. , Wako, RI Beam Science Lab., RIKEN
23) RIKEN Symp. on Production of Ultra Slow Highly-Charged Ions and Its Application
2- 3 Dec., Wako , Atomic Physics Lab., RIKEN
24) Int. Symp. on Quasiparticle and Phonon Excitations in Nuclei in Memory of Professor Vadim Soloviev(Soloviev 99)
4- 7 Dec. , Wako , Cyclotron Center, RIKEN

293

XI. LIST OF SEMINARS(Jan.- Dec. 1999)

Radiation Lab., RI Beam Science Lab., andBeam Technology Div.
1) K. Turner, BNL (USA) , 12 Jan.
"W charge asymmetry at the tevatron"
2) S. N. White, BNL (USA), 19 Jan.
"Luminosity measurement"
3) N. Saito, RIKEN (Saitama) and RBRC (USA), 26
Jan.
"Report of hadron collider physics XIII in India"
4) B. A. Brown, Michigan State University, NSCL
(USA), 1 Feb.
•
"Single-nucleon knock out from halo nuclei"
5) V. Yu. Denisov, Institute for Nuclear Research,
Kiev (Ukraine), 2 Feb.
"Subbarrier heavy ions fusion enhanced by subbarrier nucleons transfer and subbarrier fusion of
nuclei far from the beta-stability line. Formationof superheavy elements (SHEs) in cold fusion reactions"
6) L. C. Bland, Indiana University (USA), 4 Feb.
"Determining the gluon contribution to the proton's spin with STAR"
7) J. Symons, Lawrence Berkeley National Laboratory (USA), 9 Feb.
"Photon detection with the STAR detector at
RHIC"
8) J. Moss, Los Alamos National Laboratory (USA),
9 Feb.
"Spin-flavor structure of the nucleon"
9) V. Rykov, Wayne State University (USA) , 9 Feb.
"CP-odd single and double spin asymmetries in
W /Z-production by polarized hadrons and leptons"
10) N. Itagaki, Graduate School of Science, Hokkaido
University (Hokkaido), 10 Feb.
"Development of cluster structure in neutron richnuclei"Stoney Brook (USA) , 16 Feb.
"Spin asymmetries in drell-yan production of lepton pairs"
13) P. Moller, Los Alamos National Laboratory(USA) , 17 Feb.
"Topology of 1000000 grid-point fission potentialenergy surfaces"
14) A. de Roeck, DESY (Germany), 18 Feb.
"The polarized HERA project: Machine aspects
and physics program"
15) L. N. Satpathy, Institute of Physics, Bhubaneswar(India), 23 Feb.
"How to go from finite nuclei to infinite nuclear
matter"16) E. Shuryak, State University of New York, Stoney
Brook (USA), 23 Feb.
"Why and how the nucleon spin penetrates into
the glue and the sea quarks"17) K. Otsuki, National Astronomical 0 bservatory ofJapan (Tokyo), 25 Feb.
"Effect of neutrino-driven wind during a supernova explosion on nucleosynthesis through the [process"18) M. Perdekamp, RBRC (USA), 2 Mar.
"Determination of boG in compass"
19) T. Blum, RBRC (USA), 9 Mar.
"Spin on lattice"20) R. L. Jaffe, MIT (USA), 16 Mar.
"Transversity and interference fragmentation
functions"21) N. Makins, University of Illinois (USA), 18 Mar.
"Spin measurements from HERMES"22) S. Ohta, KEK (Tsukuba), 23 Mar.
"Spin on lattice II"23) A. Deshpande, Yale University (USA), 30 Mar.
"Bj sum, ~G, and O's(Q2) using pQCD analysisof gl"
24) B. Ibrahin, Cairo University (Egypt), 5 Apr.
"A method for calculating the complete expansionof the Glauber amplitude and its application to
p+6He scattering"11) K. Goeke, University of Bochum (Germany), 16
Feb.
"Deeply virtual compton scattering: Skewed parton distributions and their theory"25) M. Tannenbaum, BNL (USA), 6 Apr.
"kT issues"12) W. Vogelsang, State University of New York,26) D. Kharzeev, RBRC (USA), 13 Apr.

294

"Onia and ~G"

22 June"Transversity at STAR"27) T. Nakatsukasa, RIKEN (Saitama), 19 Apr.
"Self-consistent determination of collective coordinates"

41) A. Bruell, MIT (USA), 29 June
"HERMES results"28) M. Perdekamp, RBRC (USA) et al., 27 Apr.
"Report from DIS99"

42) D. A. Kosower, Sacley (France) , 29 June
"Parton distribution with errors"29) W. Vogelsang, State University of New York,
Stoney Brook (USA), 4 May"Further discussions on DIS99 and on the
HERMES measurement of two-hadron production"

43)30) J. Meng, Peking Univesity (China), 10 May"The surface diffuseness and the spin-orbital splitting in relativistic continuum Hartree-Bogoliubov
theory"31) M. Perdekamp, RBRC (USA), 11 May"More news from DIS99"
32) S. Pittel, Bartol Research Institute, University of
Delaware (USA), 12 May"An improved single-particle basis for nuclear
structure studies far from stability"
33) J. Pretz, BNL (USA) , 18 May"SMC's semi-inclusive measurements"34) H. Spinka, Argonne National Laboratory (USA),
25 May"Polarimetry /luminosity issues"35) G. Schrieder, Technische Universitat Darmstadt( Germany), 27 May"1) Fragment-neutron correlation in fragmentation of Halo Nuclei; 2) Tentative plans for a HIElectron-Photon Collider at GSI"36) G. Roepke, University of Rostock (Germany) , 28May
"Clusters in dense nuclear matter"37) A. Deshpande, Yale University (USA) and G.
Bunce, BNL and RBRC (USA), 1 June
"Highlights of the Hamburg meeting on polarization at HERA"
38) T. Roser, BNL (USA), 8 June
"Machine aspect of HERA-spin workshop"

s. Xu , Institute of Modern Physics, Chinese
Academy of Sciences (China), 13 July
"Beta-delayed proton decay near the proton-dripline"44) E. J. Stephenson, Indiana University (USA), 13
July"Spin dependence in charge exchange scattering"45) S. Nagataki, University of Tokyo (Tokyo), 26 July
"Explosive nucleosynthesis in SN 1987A: Jet-like
explosion inferred from the observations of 44Ti
and Fe"46) M. Anselmino, Torino University (Italy), 10 Aug.
"Single transverse spin asymmetries"47) K. Imai, Kyoto University (Kyoto), 17 Aug.
"Polarimetry at collision point"48) Y. H. Zhang, JAERI and IMP (China), 20 Aug.
"Rotational band structures in odd-odd 178, 18o Ir"49) J. Tostevin, University of Surrey (UK), 23 Aug.
"Theoretical methods for reactions of composite
nuclei"50) J. Tostevin , University of Surrey (UK) , 23 Aug.
"Exotic nucleus spectroscopy using nuclear reactions"51) E. Leader, University of London (UK), 24 Aug.
"How well do we understand the spin structure of
the nucleon?"52) A. Ansari, Institute of Physics, Bhubaneswar (India), 27 Aug.
"A microscopic study of giant dipole resonancesin hot and rotating nuclei"53) E. Leader, University of London (UK), 31 Aug.
"Collins effect"39) W. Vogelsang, State University of New York ,Stoney Brook (USA) , 15 June
"Prompt photons"54) M. Matsuzaki, Fukuoka University of Education(Fukuoka), 1 Sept.
"Constructing relativistic effective nucleonnucleon interaction for superfluid gap equation"40) A. Ogawa, Pennsylvania State University (USA),

55) J. Meng, Peking University (China), 1 Sept.
295

"Proton-neutron interactions in an extended
P+QQ force model""The structure of superheavy elements newly discovered in the reaction of 86Kr with 208Pb"
56) S. Sasaki, RBRC (USA), 7 Sept.
"Spin on lattice III"

57) A. Contogouris, Athens University (Greece), 21
Sept.
"Determinations of the polarized gluon distribution"
58)

N. Buttimore, University of Dublin (Ireland), 28
Sept.
"Spin flip in proton-carbon polarimetry"59) E. Stein, Regensburg University (Germany), 15
Oct.
"Higher twist effects for gl"60) J. Q. Chen, Nanjing University (China), 18 Oct.
"Nucleon-pair shell model calculations of theeven-even Xe and Ba nuclei"61) K. Yabana, Institute of Physics, University ofTsukuba (Ibaraki), 19 Oct.
"Time-dependent mean-field theory applied to finite electronic systems"
62)

Z. Feng-Shou, Institute of Modern Physics, Chinese Academy of Sciences (China), 26 Oct.
"Chemical instability and nuclear multifragmentation in heavy ion collisions"63) S. Kretzer, Dortmund University (Germany), 26
Oct.
"Charm production in charged current DIS"
64) R. Johnson, Surrey University, (UK), 29 Oct.
"Applications of the adiabatic approximation totransfer reactions, break-up and scattering of halo
nuclei"65) G. Baur, IKP, FZ, Julich (Germany) , 29 Oct.
"New possibilities for Coulomb dissociation"66) Y. Chen, China Institute of Atomic Energy(China), 8 Nov.
"The axial symmetry break in superdeformed nuclei"67) T . Blum, RBRC (USA), 16 Nov.
"Spin on lattice IV"

296

K.
Kaneko,Kyushu(Fukuoka), 19 Nov.

Sangyo71) H. Sato, Kyoto University (Kyoto), 23 Nov.
"Open heavy flavor production"
72)

M. Wiescher, Notre Dame University (USA), 24
Nov.
"Trigger and endpoint of the rp-process"73) Y. Zhuo, China Institute of Atomic Energy(China), 24 Nov.
"Brownian motors driven by non-equilibrium fluctuations"74)

P. Bonche, Saclay (France), 24 Nov.
"Survey of mean-field theories and beyond, from
Hartree-Fock to projected configuration mixing"75) R. Seki, California State University, Northridge,
and Kellogg Radiation Laboratory, Caltech(USA), 30 Nov.
"N uclear physics in atmospheric neutrino oscillation"76) D. Boer, RBRC (USA), 30 Nov.
"Transverse spin effects: Theory"
77)

M. Perdekamp , RBRC (USA), 7 Dec.
"Transverse spin effects: Experiment"78) M. Junker, Laboratori Nazionali del Gran Sasso(Italy), 10 Dec.
"LUNA: An underground accelerator facility for
nuclear astrophysics"79) E. Lomon, MIT/KEK-Tanashi (Tokyo), 13 Dec.
"Hadronic and quark/gluon degrees of freedom inhadron interactions"80) D. T. Khoa, Institute for Nuclear Science andTechnique, Vietnam Atomic Energy Commission(Vietnam), 14 Dec.
"Consistent study of asymmetric nuclear matter and interaction potential between neutron-richnuclei"81) F. Ivanyuk, Institute for Nuclear Research, Kiev
(Ukraine), 20 Dec.
"The pairing and shell effects in the transport coefficients of collective motion"68) T. Roser, BNL (USA), 16 Nov.
"New idea to operate snake at RHIC"
69)70) G. Levai, Institute of Nuclear Research of the
Hungarian Academy of Sciences (Hungary), 22
Nov.
"Symmetry aspects of nuclear cluster systems"

University

Atomic Physics Lab.
1) M. Kawai, T. Yoneda, and H. Okuyama, RIKEN(Saitama), 26 Jan.
"Behavior of hydrogen on surfaces"
2) S. Huldt , Lund University (Sweden), 29 June
"Instrumentation and applications for optical
spectroscopy"3) B. Zygelman , University Nevada (USA), 5 Feb.
"Spin exchange in cold collision of hydrogenatoms"

4) P. C. Stancil, Oak Ridge National Laboratory(USA), 26 Mar.
"Atomic and molecular processes in the early universe"5) M. Wada, RIKEN (Saitama), 19 Apr.
"Trapping unstable nuclear ions from RIPS andtheir applications"14) A. Kheifets , Australian National University (Australia), 8 July
"Determination of energy-momentum distributionof electron in solids by electron momentum spectroscopy"15) J. Sanderson, University College London (UK),12 July"Coulomb explosions of simple molecules in intense femtosecond laser pulses"
16) F. A. Gianturco, University of Rome (Italy), 13
July"Molecular physics at the millikelvins: Do Efimov
states exist in He clusters?"17) R. J anev, Research Center for Energy Macedonian Academy of Sciences and Arts (Macedonia) ,15 Oct.
"Atomic and molecular processes in fusion plasmas"

6) C. Guet, CEA-Grenoble (France), 20 Apr.
"Theoretical approaches to collisions of metalclusters with ions and electrons"18) Y. Iwata, Cluster Science Laboratory, ETL(Ibaraki), 12 Nov.
"New cluster beam source developed for nanometer scale patterned media technologies"

7) T. Miura, University of Tsukuba (Ibaraki), 21Mar.
"Modified interatomic potential in atom-C 60 collisions"19) I. Sakurai, RIKEN (Saitama), 26 Nov.
"Anomalous gas amplification of Xe + CO 2 proportional counter"8) N. Cherepkov, State University of Aerospace Instrument (Russia) , 4 June
"Photoionization of fixed-in-space molecules, orcomplete photoionization experiments with diatomic molecules"
9) K. Yamanouchi , University of Tokyo (Tokyo), 10
June"Chemistry in intense laser field"10) Y. Yoshida, Shizuoka Institute of Science andTechnology (Shizuoka), 11 June
"Material science with Mossbauer spectroscopy at
RI Beam Factory"
11) T. Suda, RIKEN (Saitama) , 18 June
"Production of linearly polarized photons by coherent bremsstrahlung, and a pair polarimeter"12) M. Inokuti, Argonne National Laboratory (USA),
25 June"Topics of my current and unfinished research"
13) S. J. Buckman, Australian National University(Australia), 8 July
"Cooling and trapping of metastable helium"20) H. Shiromaru, Tokyo Metropolitan University(Tokyo), 20 Dec.
"Molecular structure and equilibrium nuclear configuration revealed by Coulomb explosion"

RIBF Project Office
1) Y. Mori, KEK (Ibaraki), 12 Jan.

"High-gradient RF cavity"

2) Y. Batygin, A. Goto, and J. Kim, RIKEN(Saitama), 27 Jan.
"High current beam dynamics problems in RIBF
project"
3) T. Satow, NIFS (Chiba), 18 Mar.
"The first excitation of the Large Helical Device(LHD) "
4) M. Kaji, Mitsubishi (Tokyo), 23 Apr.
"EPIC"
5) S. Kato, KEK (Ibaraki), 23 Apr.
"How to wash surfaces of vacuum chambers"
6) J. Hasegawa, Tokyo Institute of Technology(Tokyo), 23 Aug.
297

"Development of a high brightness laser ion
source"7) S. Runkel, Frankfurt University (Germany), 16
Sept.
"The Frankfurt ECR- (ve) RFQ-Facility"
8) T. Mukhopadhyay, VECC (India), 15 Oct.
"Calculation of neutron heat loads and damages
to superconducting magnets"
9) K. Chouffani, Hiroshima University (Hiroshima),
22 Oct.
"Parametric X radiation and diffracted transition
radiation at REFER electron ring"

Radioisotope Technology Div.
1) K. Komatsu, Hiroshima University (Hiroshima),
4 Oct.
"Cloning and protein function of DNA doublestrand break repair gene NBSl"
2) A. Grosovsky, University of California (USA), 12
Nov.
"Radiation-induced genomic instability"

Computational Science Div.

"Material circulation in subduction zones"5) T. Yamamoto , RIKEN (Saitama), 13 May"Application of the molecular orbital calculation
to the atomic spectroscopy of low-Z elements"
6) K. Ohguchi, RIKEN (Saitama), 20 May"Molecular mechanism of binary nucleation in vapor phase"7) M. Matsui , Kyusyu University (Fukuoka), 11 June
"Molecular dynamics simulation of mantle minerals"8) F. Phicherri, RIKEN (Saitama), 17 June
"Probing DNA modifications by means
quantum-chemistry"of9) Y. Hamahata, Tohoku University (Miyagi), 22
June"Molecular Dynamics (MD) estimation of theelastic wave velocity and anisotropy of MgO and
MgSi03 perovskite under the lower mantle conditions"10) T. Narumi, RIKEN (Saitama), 29 June
"Progress report on the development of MDM:
Special-purpose computer for molecular dynamics
simulations"

1) R. Osman, Mount Sinai Medical University(USA) , 18 Mar.
"MD simulation of biopolymer"11) Y. Oono, RIKEN (Saitama) , 8 July
"TOMBO Project performance of prototype"2) M. Payne, University of Cambridge (UK), 19 Mar.
"Finite temperature simulations of metal surfaces
and zeolites"12) R. Susukita, RIKEN (Saitama), 26 Aug.
"MDGRAPE-2: A special-purpose computer formolecular dynamics"

3) Y. Kobayashi, Soka University (Tokyo), 25 Mar.
"Physicochemical mechanism of protein folding"13) K. Sato, RIKEN (Saitama), 15 Sept.
"The effect of quasi-liquid layer in the unstable
growth of snow crystals"

4) H. Iwamori, University of Tokyo (Tokyo), 1 Apr.

298

XII. liST OF PERSONNELRIKEN ACCELERATOR RESEARCH FACILITYTANIHATA Isao
YAN 0 Yasushige:§ tIH ~ :K

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(Facility Director)(Vice Facility Director)

Linac Division
IKEZAWA Eiji 7th iR ~KOHARA Shigeo IJ,
~ :K

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KASE Masayuki

Ring Cyclotron Division=

FUJITA Jiro Ji 83~~
IN ABE N aohito fiB:ill f6J A
KAMIGAITO Osamu J::±~)rH'~­
KOHARA Shigeo IJ~
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OGIWARA Kiyoshi ~
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KASE Masayuki 110 ~ J§
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KUBO Toshiyuki ~ {;If: ~ ¥NAKAGAWA Takahide 9=J JII ~ 3§:
OKUNO Hiroki ~ let Jt fitzExperimental Support Division

ICHIHARA Takashi
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KANAI Yasuyuki ~MATSUZAKI Teiichiro ~~dltj1~m e~
WATANABE Yasushi iJi:ii"*'*

KAMBARA Tadashi 1$
iE * 1KUMAGAI Hidekazu ~~:§ 3§: 5fD
MORITA Kosuke ~ 83 i~ 1r
YATAGAI Fumio :§H3ffitx:jc

Radioisotope Facilities Division
KOBAYASHI Yoshio IJ~:t* ~ ~YATAGAI Fumio

Radiation Protection GroupFU JITA Shin Ji 83 *Jf * 1
NAKAJIMA Shunji 9=J!ffb ~¥ITO Sachiko fft Ji :ff -=f
OGIWARA Kiyoshi ~Administration Division
NAKAMURA Toshiko
TAKEYAMA Ken-ichi=

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Steering Committee
ASAHI Koichiro 1l.!! vt-!m
HANAOKA Fumio ~ lUi] )c t.ft
ISHIHARA Masayasu 15iE ~KASE Masayuki DO 11 J§ Z
KATSUMATA Koichi .1m X W: NAGAMINE Kanetada j1<. ~ Mft I~'
TAKEYAMA Ken-ichi lEt LlJ Mft YAGI Eiichi )\YAN 0 Yasushige
let 17: ~YOSHIDA Shigeo E 83 7i:. ~

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NUMATA Shigeoi~m83 JJ. ~GOTO Akira f:&. Ji ~ICHIHARA Takashi mlj[
KAMBARA Tadashi 1$
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KATAYAMA Takeshi h LlJ lEt P]
MATSUZAKI Teiichiro ~~ilitJ1~me~
SAWA Hiroshi
7.i.
TANIHATA Isao :§ ~HI ~ :K
YAMAZAKI Yasunori LlJ ib~ ~ ~J! *3
YATAGAI Fumio :§83J!)c:K

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Cosmic Radiation Laboratory
Members
KATO Hiroshi
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YOSHIDA Atsumasa~ EEl ~ 1I*

Visiting Members and Postdoctoral Fellows
GOKA Tateo Ii~:;K(NASDA)
KATO Chihiro~ -T ~(Fac. Sci., Shinshu Univ.)
KOGA Kiyokazu ti ~ 1N (NASDA)
KOSHIISHI Hideki ~ D "!i: f!J (NASDA)
Bff ~ (NASDA)
MATSUMOTO Haruhisa tJ}
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MUNAKATA Kazuoki

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MIYASAKA Hiromasa

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Radiation Laboratory
Head
ISHIHARA Masayasu

D JJj{ 1I ~Members
ICHIHARA Takashi
JJj{lj[
SAITO Naohito 71f jffi @[ A
TAKETANI Atsushi ¥r ~ ~YOSHIDA Atsushi ~ EEl ¥.tm(Grad. Sch. Sci. Eng., Saitama Univ.)

KISHIDA Takashi J¥ EEl ~i
SAKURAI Hiroyoshi tl it t.f ~WATANABE Yasushi Vi jf

Visiting Members and Postdoctoral Fellows
ABE Yasuhisa ~iiJ ir5~(YITP, Kyoto Univ.)
ANDO Yoshiaki~ ¥o ~(ColI. Sci., Rikkyo Univ.)AOI Nori W it 1f (Dept. Phys., Grad. Sch. Sci., Univ. Tokyo)
ASAI Masato r~ it ~ A (J AERI)
AWAYA Yoko ~ §f ~ ~ (Musashino Art Univ.)
BECK F. A.
(CRN, France)
BENTZ Wolfgang(Dept. Phys., Grad. Sch. ScL, Univ. Tokyo)
BROGLIA R.
(Univ. Milano, Italy)(LANL, USA)BROOKS Melynda L.
CASTEN Rick(Phys. Dept., BNL, USA)
CRIST Norman(Columbia Univ., USA)DOOI Makoto lit it ~ (Inst. Phys., Univ. Tsukuba)
EN'YO Hideto ~ W. 1§ A (Fac. Sci., Kyoto Univ.)
FLOCARD Hubert(Div. Phys. Theor. lPN, Inst. Phys. Nucl., France)
FUCHI Yoshihide i~U ~f 1§ (KEK, Tanashi)
FUJII Hirotsugu jffi it 7i:.
(Grad. Sch. Arts Sci., Univ. Tokyo)
FUJIKAWA Kazuo ~ 111 fO ~ (Fac. Sci., Univ. Tokyo)
FUKUDA Mitsunori f~ EEl 7t)il~ (Grad. Sch. Sci., Osaka Univ.)
FUKUDA Tomokazu t~ EEl ~ fO (KEK)
FUKUDA Naoki t~ ill @[ ltt (Dept. Phys., Grad. Sch. Sci., Univ. Tokyo)
FURUTAKA Kazuyoshi ti?£s fO t~ (J AERI)GELBERG Adrian(Koln Univ., Germany)
GO NO Yasuyuki ms Jl ~tf Z (Fac. Sci., Kyushu Univ.)
GOTO Yuji 1& Ji iii
HAMAGAKI Hideki i~:l:l! 1§ fM (Cen. Nucl. Study, Univ. Tokyo)
HAMAMOTO Ikuko i~
1f ~ (Lund Inst. Technol., Univ. Lund , Sweden)
HATSUDA Tetsuo fJJ EEl :gr:513 (Fac. Sci., Kyoto Univ.)
HAYASHI N aoki@[ t!tHAYASHIGAKI Arata*Jf (YITP, Kyoto Univ.)

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**:1:]:'*HIRAI Masaaki f # iE EljJHORIUCHI Hisashi :ifttl I*J 7j{! (Fac. Integr. Human Studies, Dept. Fundamental Sci., Kyoto Univ.)
HOSAKA Masahito {*:t&;jq. A (KEK, Tanashi)
HOTTA Tomohiro :tJili EEl ~ ~$ (Grad. Sch. Arts Sci., Univ. Tokyo)
ICHIMURA Munetake mft
fElt (Grad. Sch. Arts Sci., Univ. Tokyo)
IDEGUCHI Eiji #~D*is (Phys. Dept. Frescati, Royal Inst. Technol., Sweden)~ fO 72:(ColI. Sci., Rikkyo Univ.)
IEKI Kazuo
IMAI Kenichi 4- # )f- (Fac. Sci., Kyoto Univ.)
IMOTO Michiko #:@(Lab. Phys., CoIl. Sci. Technol., Nihon Univ.)
ISHII Tetsuro E # ~ f!~ (J AERI)
ITAKURA Kazunori f.oc ~ fO ~c (YITP, Kyoto Univ.)
IWASAKI Hironori :'5 1iJ~ '5t. ~ (Dept. Phys., Grad. Sch. Sci., Univ. Tokyo)
IZUMI Hideaki ill~ EY3(Grad. Sch. Sci., Osaka Univ.)
JIN Genming ~Jf t~ EY3 (Inst. Modern Phys., Chinese Acad. Sci., China)
KAKI Kaori ~:m~(Fae. Sci., Shizuoka Univ.)
KAMAE Tsuneyoshi ~ iI 1ft ~f (Fac. Sci., Univ. Tokyo)
KASAGI Jirota j£*ise~* (Lab. Nucl. Sci., Tohoku Univ.)
KATAYAMA Ichiro h ill - e~ (Cen. Nucl. Study, Univ. Tokyo)
K~TO Seigo 110 Ji m- ~(Fae. Ed., Yamagata Univ.)(Lab. Nuel. Studies, Fac. Sci., Osaka Univ.)
KATORI Kenji J1[ JfX: ~KAWASHIMA Hideo )11 ~ "!i:.
(KEK, Tanashi)
KIM Jong Chan i: Jl j{ (Dept. Phys., Seoul Natl. Univ., Korea)
KISTENEV Edouard(Phys. Dept., BNL, USA)KITAO Kensuke %~~§!IJJ (Data Eng. Inc.)KODAIRA Jirou IJ'\ f is e~ (Fac. Sci., Hiroshima Univ.)
KOHAMA Akihisa IJ'\ it ?$ ~ (Fac. Sci., Univ. Tokyo)
KOIKE Yuji IJ'\ illi tfi P] (Fac. Sci., Niigata Univ.)
KUBONO Shigeru ~f*ff(Cen. Nucl. Study, Univ. Tokyo)
KUMANO Shunzo ~~ mt 1~ := (Fac. Sci. Eng., Saga Univ.)
KUNIHIRO Teiji ~ '5t. 'It(Ryukoku Univ.)
KURITA Kazuyoshi ~ EEl fO ~fKUSAKARI Hideshige 1fI)(1j"!i:.
(Fac. Ed. , Chiba Univ.)
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)LUCCIO Alfredo(Phys. Dept., BNL, USA)
MAO Yajun(Phys. Dept., BNL, USA)
MATSUDA Satoshi t;} EEl ~ (Fac. Integr. Human Studies, Dept. Fundamental Sci., Kyoto Univ.)
MATSUI Tetsuo t~;#: =rg-:!13 (YITP, Kyoto Univ.)
MATSUYANAGI Kenichi t;} tgp fiJf (Fac. Sci. , Kyoto Univ.)
MENGONI Alberto(Phys. Div., ENEA, Italy)
MIN Byung-Joo 00 ~(Korea Atom. Energy Res. Inst., Korea)
MITARAI Shiro 1~~i7t;:te~ (Fac. Sci., Kyushu Univ.)
MIYAMA Masanori i* ill iE if.2. (Fac. Sci. Eng. , Saga Univ.)
MIYATAKE Hiroari '8-ti2 (KEK, Tanashi)
MIZOI Yutaka iff.;#: i-j5:
MORII Toshiyuki ~;#: 1~ iT (Fac. Human Dev., Kobe Univ.)
MORIKAWA Tsuneyasu ~)II tg Y: (Fac. Sci., Kyushu Univ.)
MORINOBU Shunpei ~ 18" {~f (Fac. Sci., Kyushu Univ.)
MOTOBAYASHI Tohru~(ColI. Sci., Rikkyo Univ.)
MOTTELSON Ben R.
(Nordita; Nordisk Inst. Theoretisk Fysik, Denmark)
MUELLER Ludwig(Phys. Dept., Univ. Padoba, Italy)
MURAKAMI Takeshi ft L 1l: (N atl. Inst. Radiol. Sci.)
MURATA Jiro tt EEle~
NAGAI Yasuki 7k;#: ~ fit (RCNP, Osaka Univ.)
NAGAMIYA Shoji 7k '8 iE is (KEK)
NAITO Kenichi I*J Hi ~ -

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NAKAMURA Shogo $ ~t 1£ 1fr (Fac. Ed., Yokohama Natl. Univ.)
NAKAMURA Takashi $ ~t ~i 1§1 (Natl. Supercond. Cycl. Lab. , Michigan State Univ. , USA)
NAKAMURA Masanobu $ ft 1£ 1~ (Fac. Sci. , Kyoto Univ.)
NAKAYAMA Shintaro $ UJ1~* e~ (Fac. Integr. Arts Sci. , Univ. Tokushima)
NEMOTO Yukio fN.
¥ il (RCNP, Osaka Univ.)
NIIZEKI Takashi *fT IMj ~i (Fac. Sci., Tokyo Inst. Technol.)NISHIMURA Jun 1§ ft ?.!f. (Cen. Integr. Res. Sci. Eng., Nagoya Univ.)
NISHIMURA Syunji 1l!3 ft 1~(Cen. Nucl. Study, Univ. Tokyo)
NORO Tetsuo ff g ~ X (RCNP, Osaka Univ.)
NOTANI Masahiro ff ~ *1- rt
ODAHARA Atsuko IJ'\EEJjj(~-=t- (Nishinippon Inst. Technol.)
OG AWA Masao IJ'\ ]II ~ ~ (Tokyo Inst. Technol.)EE irt ~ (KEK)
OHTA Shigemi
01 Makito *#7Jif-CA (Cen. Nucl. Study, Univ. Tokyo)
OKAMURA Hiroyuki IHiJ ~t 51\ Z (Dept. Phys. , Grad. Sch. Sci. , Univ. Tokyo)
OOISHI Ryutaro *Dii*e~ (Inst. Phys., Univ. Tsukuba)
OOYAMA Ken
UJ ~ORIHARA Hikonojyo tlJjj(jfgzZR (Cycl. Radioisot. Cen., Tohoku Univ.)~ ~ M(J AERI)
OSHIMA Masumi
OTSUKA Takaharu±~ 1f:- 16(Fac. Sci., Univ. Tokyo)
PENIONZHKEVICH Iouri(Flerov Lab. Nucl. React. , Joint Inst. Nucl. Res., Russia)
PIERROUTSAKOU Dimitra (Sez. Napoli (INFN) , Italy)
REN Zhongzhou 11 $ ifH (Nanjing Univ., China)
SAGAWA Hiroyuki 1!]l1 5L. ¥(Cen. Math. Sci., Univ. Aizu)
SAKAGUCHI Harutaka tx 0 16 ~i (Fac. Sci., Kyoto Univ.)
SAKAI Kenji ?~ # ~(Tokyo Inst. Technol.)
SAKURAGI Hiroyuki tf
5L. Z (Fac. Sci., Osaka City Univ.)
SATO Hikaru 1! Jli BB (KEK)
SATO Hiroki D. 1! Jli tf oc (Fac. Sci., Kyoto Univ.)
SAWADA Shinya if EE ~ ill (KEK)
SCHAEFER Markus(Phys. Inst., Univ. Goettingen, Germany)
SCHMIDT-OTT Wolf-Dieter(Phys. Inst., Univ. Goettingen, Germany)
SEDERWALL Bo(Royal Inst. Technol., Sweden)
SHIBATA Toshi-Aki ~ EE flj Bjj (Tokyo Inst. Technol. )~(Fac. Ed., Yamagata Univ.)
SHIMIZU Hajime ¥w
SHIMIZU Yoshifumi 1W.& Y:. (Fac. Sci., Kyushu Univ.)
SHIMODA Tadashi r EE 1£ (Grad. Sch. Sci., Osaka Univ.)
SHIMOURA Susumu r iffi
(ColI. Sci., Rikkyo Univ.)
SIGNORINI Cosimo I.
(Phys. Dept., Univ. Padoba, Italy)
STROE Lucian(Phys. Dept. , Univ. Padoba, Italy)
SUGAWARA Masahiko ;g Jjj( J§ jfg (Chiba Inst. Technol.)
SUGIOKA Makoto ifb IHiJ IDit
SUN Zuxun(China Inst. Atom. Energy, China)
SUZUKI Yasuyuki ~fl
1L Z (Fac. Sci., Niigata Univ .)SUZUKI Katsuhiko ~fl
E jfg (RCNP, Osaka Univ.)
SUZUKI Toshio ~fl
fit J.J (Fac. Eng., Fukui Univ.)
TAJIMA Yasuhisa EE ~ ~~ 0.. (Cycl. Radioisot. Cen., Tohoku Univ.)
TAKADA Eiichi ~ EE
(N atl. Inst. Radiol. Sci.)(Inst. Space Astro. Sci.)
TAKAHASHI Tadayuki ~ mJ~' ¥TAKAKU Seisaku ~ 0.. ¥w fF (KEK, Tanashi)
TAKIGAWA Noboru r~]l1 ~ (Grad. Sch. Sci., Tohoku Univ.)
TAKIZAWA Makoto in if IDit (Showa ColI. Pharm. Sci.)
TAMIl Atsushi ~ #?.!f.
(Fac. Sci., Univ. Tokyo)
TANAKA Masahiko EE $ ~ jfg (KEK, Tanashi)
TANOKURA Atsushi EE~j'- ~i (Fac. Sci. Technol. , Sophia Univ.)
TENDOW Yoshihiko 7( ~ 7i "&

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302

TERAKAWA Atsuki ~]l1 J.: Ut (Cycl. Radioisot. Cen., Tohoku Univ.)
TERANISHI Takashi ~ 1§ ~ (Cen. Nucl. Study, Univ. Tokyo)
TORI! Hisayuki ,~# ~ iT (Fac. Sci., Kyoto Univ.)
TOYAMA Takeshi )t} LlJ ~ (KEK)
TOYOKAWA Hidenori ':']11~)II
UEMATSU Tsuneo M: tl 'tg:t: (Fac. Integr. Human Studies, Dept. Fundamental Sci., Kyoto Univ.)
UENO Hideki ...t!fUt (Lab. Nucl. Studies, Fac. Sci., Osaka Univ.)
UNO Masahiro +!f 1£ 1i (Min. Ed. Sci. Sports Culture)
WAKAMATSU Masashi ~ f11£ it (Lab. Nucl. Studies, Fac. Sci., Osaka Univ.)
WAKASA Tomotsugu ~ ~ ~ fffl~ (RCNP, Osaka Univ.)
WATANABE Yutaka ili:ill
WATANABE Hiroshi ili 51 J! (Fac. Sci., Kyushu Univ.)
WHITE Sebastian(Phys. Dept., BNL, USA)XU Shuwei 1~ fit ~ (Inst. Modern Phys., Chinese Acad. Sci. , China)
YAMAMOTO Su'keyasu LlJ
t.tJ ~~ (Fac. Sci. Technol., Sophia Univ.)-tQ (Fac. Eng., Fukui Univ. Technol.)
YAMANISHI Teruya LlJ 1§
YAMASHITA Yoshiki LlJ T 7i fM (Hirosaki Univ.)
YANAGISAWA Yoshiyuki f#P rR if iT (Cen. Nucl. Study, Univ. Tokyo)(Tokyo Woman's Chr. Univ.)
YAZAKI Koichi 9c 1iJ~ ffft YOKKAICHI Satoshi 1m B
H~·
(Fac. Sci., Kyoto Univ.)
YOSHIMURA Koji E tt ilff PJ (Int. Cen. Element. Part. Phys., Univ. Tokyo)
YOSHINAGA Naotaka E j1< r116 ~ (Fac. Sci., Saitama Univ.)YOSOI Masaru W~# 11 (Fac. Sci., Kyoto Univ.)
ZHANG Yu-Hu~~
I re (Inst. Modern Phys., Chinese Acad. Sci., China)
ZHU Lihua(China Inst. Atom. Energy, China)

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Trainees
BABA Hidetada ,~:t~,'i!;, (ColI. Sci., Rikkyo Univ.)
FUKUCHI Tomonori 1M:Iili ~O ~u (Fac. Sci., Kyushu Univ.)
FUKUSAKA Shouichi 1M tx ~q. (Dept. Phys., Grad. Sch. Sci., Univ. Tokyo)
FUTAKAMI Udai =...tr*J (ColI. Sci., Rikkyo Univ.)
GOMI Tomoko Ii ~ ~J3 r(ColI. Sci., Rikkyo Univ.)
HATANO Michio r~83!fill:t: (Dept. Phys., Grad. Sch. Sci., Univ. Tokyo)
HIRAI Masanori ~ # 1£ *2. (Fac. Sci. Eng., Saga Univ.)
IMAI Nobuaki ~ # 1$ ~(Dept. Phys., Grad. Sch. Sci., Univ. Tokyo)
KASHIYAMA Osamu ~ LlJ 11~ (Fac. Sci., Kyushu Univ.)
KATO Hiromitsu DO Hi
7C (Dept. Phys., Grad. Sch. Sci., Univ. Tokyo)
KINUGAWA Hiroto 7f.)l1
A (ColI. Sci., Rikkyo Univ.)
KOBAYASHI Hiroshi IJ'\
J! (ColI. ScL, Rikkyo Univ.)
KUNIBU Makoto ~ 5t m (ColI. Sci., Rikkyo Univ.)
MAEDA Yukie 1W 83 ¥ £(Dept. Phys., Grad. Sch. Sci., Univ. Tokyo)
MICHIMASA Shinichiro ill1£*Jf-~~ (Fac. Sci., Univ. Tokyo)
MINEMURA Toshiyuki
tt 1~ iT (ColI. Sci., Rikkyo Univ.)
MITSUHASHI Toshiya
flJ -tQ (Dept. Phys., Grad. Sch. Sci. , Univ. Tokyo)
MIYAKAWA Takahiko 8)11 J.: ~ (Fac. Sci. , Tokyo Metrop. Univ.)
MOTOMURA Shinji
tt 1~ r5 (Fac. Sci., Kyushu Univ.)
MUTO Ryotaro m:Hi3t*~~ (Fac. Sci., Kyoto Univ.)
NAKAJIMA Noriaki ~ ~ ~ BE (RCNP, Osaka Univ.)
NAKANO Eiji frp!f 9!i: PJ (Fac. Sci., Tokyo Metrop. Univ.)
NAKANO Jo ~!f Ml (Cen. Nucl. Study, Univ. Tokyo)
OHKUMA Kazumasa~~
1£ (Fac. Human Dev., Kobe Univ.)
SAHA Pranab(KEK)
SAITO Koji ~ ji r~ PJ (Fac. Sci., Kyushu Univ.)
SAITOU Akito ~ Hi B~ 1t (CoIl. Sci., Rikkyo Univ.)
SAKODA Seitaro :i.E!83m*~~ (Dept. Phys., Grad. Sch. Sci. , Univ. Tokyo)
SERATA Masaki iit.&83~* (ColI. Sci., Rikkyo Univ.)
SUDOH Kazutaka 3..E{ Ji fo tjX (Fac. Human Dev., Kobe Univ.)

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303

SUETSUGU Kentaro *;X'&t*~~ (Tokyo Inst. Technol.)
TANIGUCHI Etsuji B- 0 'l:R. ~ (Tokyo Inst. Techno!.)TOJO Junji~ )II¥i ¥6(Fac. Sci., Kyoto Univ.)
WATANABE Eitoku ill ill #i; if- (Dept. Phys., Grad. Sch. Sci., Univ. Tokyo)
YAKO Kentaro *roJ~*~~ (Dept. Phys., Grad. Sch. Sci., Univ. Tokyo)
YAMADA Kazunari UJ 83 - $: (ColI. Sci., Rikkyo Univ.)
YONEDA Kenichiro *EBll-~~ (Dept. Phys ., Grad. Sch. Sci., Univ. Tokyo)"*

RI Beam Science Laboratory
Head
TANIHATA Isao

B- iff! ~ ~Members
KORSHENINNIKOV Alexei A.
MATSUO Yukari tJ}~Ef3ji~1j
OZAWA Akira /J'\ 7R ~Ji
SUMIYOSHI Kohsuke 11 E It 1r
YOSHIDA Koichi E 83 It -* *KUMAG AI Hidekazu 1f~ Bfo
MORIMOTO Koji ~¥ PJSUDA Toshimi ~J{ 83 ~Ij ~TO NUMA Tadao P ¥f5 iE tit

Visiting Members and Postdoctoral Fellows
AOYAMA Shigeyoshi W UJ~
(Kitami Inst. Tech.)
ADACHI Shizuko 1i: Jt II- T(ICFD)
AHMADY Mohammad(Western Ontario Univ. , Canada)
ARATANI Michi 5iL B- ~ ~ (Inst. Environ. Sci.)
BOLBOT Michael(Notre Dame Univ., USA)BORDEANU Cristina (Horia Hul. Natl. Inst. , Romania)
BOYD Richard(Ohio Univ., USA)
BROCKMANN Roff (Inst. Phys., Univ. Mainz, Germany)
CRUCCERU Hie(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 ~,'i!;!, ~ (Adv. Res. Inst. Sci. Eng., Waseda Univ.)
ENYO Yoshiko ~ W f1 T
(Cen. Nucl. Study, Univ. Tokyo)
FU JIWARA Mamoru jffi W- ~ (RCNP, Osaka Univ.)
FULOP Zsolt(ATOMIKI, Hungary)
GACSI Zoltan(ATOMKI, Hungary)
GEISSEL Hans
(GSI, Germany)
GIURGIU Mircea(Horia Inst. Nucl. Eng., Romania)
GOLOVKOV Mkheil S.
(Kurchatov Inst., Russia)
GONCHAROV Sergei A.
(Kurchatov Inst., Russia)
GOSWAMI Ranjana (Variable Energy Cycl. Cen. Calcutta, India)
GUNJI Shuichi W PJ 1~ (Fac. Sci., Yamagata Univ.)
HASEBE Nobuyuki ffi:B-g.~f$1T (Fac. Sci. Eng., Waseda Univ.)
HIRENZAKI Satoru Itj!!ll~ 'I! (Fac. Sci., Nara Women's Univ.)
HORIUCHI Hisashi tlli pq 7N! (Fac. Sci., Kyoto Univ.)
ISHIMOTO Shigeru fj 5C(KEK)
ITAGAKI Naoyuki ~.&: j:~ @: Z
IWAMOTO Akira -;fiBB (JAERI, Tokai Res. Estab.)IZUYAMA Takeo ffl"RLlJ'&t~ (Fac. Sci., Toho Univ.)
KANEKO Kazuya ~ T fo -lli (Kyushu Sangyo Univ.)
KANUNGO Rituparna(Saha Inst. Nuc!. Phys., Calcutta, India)
KATORI Kenji F.l If~ ~KIKUCHI Jun $jij?ill }/I¥i (Sci. Eng. Res. Lab., Waseda Univ.)
KIMURA Kikuo *;ft%~tit (Fac. Eng., Nagasaki Inst. App!. Sci.)

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304

**

KOBAYASHI Toshio IJ . .
1~ it(Fac. Sci., Tohoku Univ.)
KOLATA James(Notre Dame Univ., USA)KUMARU, Suresh(Bhabha Atom. Res. Cen., India)
KUSAKA Kensuke B T ~ tt
LE Hong Khiem(Inst. Phys., Natl. Cen. Sci. Technol., Vietnam)
LIU Xin(Inst. Nucl. Study, Univ. Tokyo)
MARUYAMA Koichi 1L!lJ 115- (Inst. Nucl. Study., Univ. Tokyo)
MARUYAMA Tomoyuki 1L!lJ ~ ¥(Nihon Univ.)
MATSUOKA Nobuyuki *~ lUi] {$ iT (RCNP, Osaka Univ.)(Fac. Sci., Osaka Univ.)
MATSUTA Kensaku t~ ~ ~MATSUYAMA Yoshitaka tl!lJ 7i ~ (Inst. Nucl. Study., Univ. Tokyo)
MINAMISONO Tadanori J¥j I:IJ ,'iE', ~IJ (Fac. Sci., Osaka Univ.)
MITTING M.
(GANIL, France)
MIYAKE Yasuo =: ~ ~~}j (Fac. Sci., Univ. Tsukuba)
MIYAMURA Osamu g 1-1 {I~ (Fac. Sci., Hiroshima Univ.)
MOCHIZUKI Yuko ~ J:I f~ ::;MOMOTA Sadao 8HHt~!:t (Kochi Univ. Technol.)
MURAOKA Mitsuo f1 lUi] 7t!J5 (Fac. Eng., Aomori Univ.)
NAKATSUKASA Takashi $ f~ ~NOJIRI Yoichi ~ JJL i$ (Kochi Univ. Technol.)
OGAWA Kengo IJ . . }l1 ~ 1J- (ColI. Arts. Sci., Chiba Univ.)
OGAWA Yoko IJ . . JII i$::;- (Fac. Sci., Osaka Univ.)(Kurchatov. Inst., Russia)
OGLOBLIN Alexei A.
OHTSU Hideaki "*~.f
B% (Fac. Sci., Tohoku Univ.)
OHTSUBO Takashi
r-f ~j: (Fac. Sci., Niigata Univ.)
OMATA Kazuo IJ . . 1* *O:}( (Inst. Nucl. Study, Univ. Tokyo)
ONISHI Takashi
I!§"
ORYU Shinsho ~ fL. 1f;f.f (Fac. Sci. Technol., Sci. Univ. Tokyo)
OYAMATSU Kazuhiro ~1 t~ *0 115- (Aichi Shukutoku Univ.)
PETRASCU Horia (Horia Inst. Phys. Nucl. Eng., Romania)
PETRASCU Marius(Horia Inst. Phys. Nucl. Eng., Romania)
SAGAWA Hiroyuki {t)ll ~t. ¥(Cen. Math. Sci., Univ. Aizu)
SAKAI Hideyuki ?@ if: "!i: iT (Fac. Sci., U niv. Tokyo)
SAKURAI Hirohisa tM if: f;jX 7.,. (Fac. Sci., Yamagata Univ.)
SATO Kazuhiro {t ni *0 ~$ (Tokyo Fire Dept.)
SEKI Ryoichi ~ :/Ij (California Univ., USA)SHERRIL B.
(Michigan State Univ., USA)SHIBATA Mitihiro ~ 83 ~J. ~ (Dept. Energy Eng. Sci., Nagoya Univ.)
SHIBATA Toru ~ 83 fiji (Sci. Eng., Aoyama Gakuin Univ.)
SUGANUMA Hideo 1f ¥t5 *:}( (RCNP, Osaka Univ.)
SUGAWARA Masahiko 1f JJj{ @§ ~ (Fundam. Sci., Chiba Inst. Technol.)
SUMMERER Klaus(GSI, Germany)SUZUKI Hideyuki ~f;"!i: Z (KEK)SUZUKI Takeshi ~f;~(Fac. Sci., Niigata Univ.)
SUZUKI Tsuneo ~f;,\:g it (Fac. Sci., Kanazawa Univ.)
SUZUKI Yasuyuki ~f;'g Z(Fac. Sci., Niigata Univ.)
TACHIBANA Takahiro t~ ~ t-t (Sen. High Sch., Waseda Univ.)
TAKAHASHI Yoshiyuki ~ m ~ ¥(Alabama Univ., USA)
TAKAHASHI Yutaka ~(Fac. Sci., Osaka Univ.)
TAKANO Masatoshi JI ~ lE flj (Fac. Sci. Eng., Waseda Univ.)
TOKANAI Fuyuki r~ pt ~ tM (JST)TOKI Hiroshi ± II&: tf (RCNP, Osaka Univ.)TORBJOEN Baeck (Stockholm Univ., Sweden)
TOSTEVIN Jeffrey A.
(Univ. Surry, India)
UCHIHORI Yukio I*J m ¥:}( (Inst. Rad. Sci.)
VARGA Kalman(Inst. Nucl., Hungarian Acad. Sci., Hungary)
WADA Takahiro *0 83 ~i 7i:. (Fac. Sci., Konan Univ.)

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305

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WINKLER Martin(GEl, Germany)
YAGI Hirosuke J\
i1!r ,iii (Fac. Sci., Univ. Tsukuba)(Fac. Sci., Univ. Tokyo)
YAMADA Shoichi LlJ B3 • YAMAGUCHI Takayuki LlJ 0 .. ZYORANN Alhassid(Yale Univ., USA)YUZUKI Akira 1m(Toshiba Corp.)
ZAHAR Mohamed(Dept. Phys., Notre Dam Univ., USA)ZHENG Tao
(Fac. Sci. Techno!., Sci., Univ. Tokyo)

* .;

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Trainees
AOKI Yuka W
E13 W (Fac. Sci., Tohoku Univ.)
FUZIMURA Takeshi Jii ft ffi (Sci. Eng., Aoyama Gakuin Univ.)
HARA Kenichiro '* ~-~J3 (Fac. Sci. Eng., Waseda Univ.)
HIBINO Masaru B ltlff fl (Fac. Sci. Eng., Waseda Univ.)
IHARA Akifumi #'*BEJf.2.~ (Fac. Sci. Eng., Waseda Univ.)
KATO Tomomi DO Jii ~(Fac. Sci., Niigata Univ.)
KATO Toshiyuki DO Jii {~¥ (Fac. Sci. Eng., Waseda Univ.)
KAWA Tadahisa i~ ,~, A (Fac. Sci., Osaka Univ.)(Fac. Sci. Eng., Waseda Univ.)
KIHIRA Eiichi E ~KITANI Takao
B- ..
(Fac. Sci. Eng., Waseda Univ.)
KIYAMU Atushi %B-lE\:~.se. (Fac. Sci. Eng., Ibaraki Univ.)
KURIYAMA Koji ~ LlJ ¥ 18 (Sci. Eng., Aoyama Gakuin Univ.)
MASUMURA Takahiro :t~ ft ~ i$ (Fac. Sci. Eng., Waseda Univ.)
MINAMISONO Kei i¥i III §(Fac. Sci., Osaka Univ.)
MUTO Nobuo lE\: Jii {g- iLft (Fac. Eng., Aoyama Gakuin Univ.)OHZEKI Kazuki 7:. ~(Fac. Sci., Tohoku Univ.)
NISHIKIDO Humihiko JIfl p )("& (Fac. Sci. Eng., Waseda Univ.)
OKUDA Takashi ~ 83 .. it (Fac. Sci., Tohoku Univ.)
OKUDAIRA Osamu ~ ~ {~ (Fac. Sci. Eng., Waseda Univ.)
OZAKI Kiminori ~ III~ 0: ~t (Fac. Sci. Eng., Waseda Univ.)
SAKAGUCHI Takao :fR 0 .. 5J5 (Fac. Sci. Eng., Waseda Univ.)
SASAKI Makoto 1tc4* ~ (Fac. Sci., Osaka Univ.)
SATO Kazunori 1tc Jii
J:IIJ(Fac. Sci., Osaka Univ.)
SEKIGUCHI Masatugu ~ 0 J§ ffii~ (Fac. Sci., Tohoku Univ.)
SHIMIZU Noritaka ¥w
J:IIJ 4(Fac. Sci., Univ. Tokyo)
SUGIMOTO Satoshi t~
If:t (RCNP, Osaka Univ.)
TAKEMURA Haruyuki rr ft
tL (Fac. Sci. Eng., Waseda Univ.)
TAKENAKA Sunao rr ~ ~ (Fac. Sci. Eng., Waseda Univ.)
TAKENOUCHI Masatoshi rrZr*fiE{~ (Fac. Sci. Eng., Waseda Univ.)
TAKEUCHI Satoshi m: I*J If:t (Fac. Sci., Rikkyo Univ.)
TANAKA Motoyuki 83 ~ ~ Z (Fac. Sci., Waseda Univ.)
TAZAWA Shinya 83 ¥R 1$ iQ (Fac. Sci., Tohoku Univ.)
TERASAWA Kazuhiro ~ ¥R fo i$ (Fac. Sci. Eng., Waseda Univ.)
TERASAWA Mariko ~i'JnI~ (Fac. Sci., Univ. Tokyo)
TERUHI Shigeru ~~ B ~ (Fac. Sci. Eng., Waseda Univ.)
UMEMURA Tomohiro ffiJ ft ~J.I"5t. (Fac. Sci. Eng., Waseda Univ.)
UZIIE Toru ~fiji (Fac. Sci., Tohoku Univ.)
WAKASAYA Yoshiaki ~5;1{B-~tl~ (Fac. Sci. Techno!., Sci. Univ. Tokyo)
WANG Haiming 1: iti ~~ (Fac. Sci., Univ. Tokyo)
YAMAGUCHI Yoshitaka LlJ 0 E13 ~ (Fac. Sci., Niigata Univ.)
YAMASHITA Masaki LlJ T ~ fM (Adv. Res. Inst. Sci. Eng., Waseda Univ.)
YAMASHITA Naoyuki LlJ T ~ Z (Fac. Sci. Eng., Waseda Univ.)
YASHIRO Junichi
1t i¥ (Fac. Sci. Eng., Waseda Univ.)** * a-

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306

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Applied Nuclear Physics Laboratory
Head
ASAHI Koichiro 1t!! fjj:- ~~Members
KOBAYASHI Yoshio

IJ,

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Visiting Members and Postdoctoral Fellows
EINAGA Yasuaki %::&
f!J3 (Fac. Sci., Univ. Tokyo)
KUBO Kenya IJ\ 1~ ~ ~ (Fac. Sci., Univ. Tokyo)
OGAWA Hiroshi IJ,]II tf ffiim (Fac. Sci., Tokyo Inst. Technol.)
SAKAI Kenji ?~ #- ~(Fac. Sci., Tokyo Inst. Technol.)
UENO Hideki J:. If ~:fit (Fac. Sci., Osaka Univ.)
YAMADA Yasuhiro Ll.J EEl
i$ (Fac. Sci., Sci. Univ. Tokyo)='*

Trainees
GOTO Atsushi Ii. ~ ~t (Fac. Sci., Tokyo Inst. Technol.)~ 1~:tit(Fac. Sci., Tokyo Inst. Technol.)
HONDA Toshiki
HORI Kentaro ifttl ~*~~ (Fac. Sci., Sci. Univ. Tokyo)
KATSUMATA Keiichi JJ9} X § (Fac. Sci., Sci. Univ. Tokyo)
MIYAZAKI Junn '8 ~~ j.!f- (Fac. Sci., Sci. Univ. Tokyo)
MIYOSHI Hisanori =: ~f ,1<. tg- (Fac. Sci., Tokyo Inst. Technol.)
NAGAKURA Masaki :&:§- iE:tit (Fac. Sci., Tokyo Inst. Technol.)
OGAWA Shigeru Ij,)l1 1f (Fac. Sci., Shizuoka Inst. Sci. Tech.)
ONO Yuuki Ij, If *ti :tit (Fac. Sci., Sci. Univ. Tokyo)
SHIMAZAKI Hideo ~ ~~ ~ ~ (Fac. Sci., Sci. Univ. Tokyo)
SHIMIZU Yasunori
JjJ (Fac. Sci., Shizuoka Inst. Sci. Tech.)
SUGA Toshitaka ~J{ ~ fijk 1f. (Fac. Sci., Tokyo Inst. Technol.)SUZUKI Takayuki
j~1f. ~ (Fac. Sci., Tokyo Inst. Technol.)
YOGO Katsunori ~ ~ft 5'2: *C (Fac. Sci., Tokyo Inst. Technol.)
YOSHIMI Akihiro ~ J! '~i$ (Fac. Sci., Tokyo Inst. Technol.)

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Atomic Physics Laboratory
Head

YAMAZAKI Yasunori

Ll.J ~~* 1J?

Members
KAMBARA Tadashi 1$ JJj( iE
KOJIMA Takao M. Ij, ~ ~i ~NISHIDA Masami I§ EEl ~ ~OYAMA Hitoshi
Ll.J ~
WADA Michiharu *0 EEl ili*-

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KANAI Yasuyuki ~ # 1* Z
NAKAI Yoichi 9 # 1% oURA Masaki
iE :titSHIMAMURA Isao ~ ft ~*-?m

Visiting Members and Postdoctoral Fellows
ANDO Kozo ti: Ri jMJlj =:AZUMA Toshiyuki~ 1T(Inst. Appl. Phys., Univ. Tsukuba)
BRAGE Tomas(Dept. Phys., Univ. Lund, Sweden)
CHIMI Yasuhiro ~O J!
~t.
(JAERI, Tokai Res. Estab.)
CIORTEA Constantin(Nat!. Inst. Phys. Nuc!. Eng., Romania)
DATZ Sheldon(Oak Ridge Nat!. Lab., USA)
DEPAOLA Brett(Dept. Phys. Kansas State Univ. , USA)
DUMITRIU Dana
(Nat!. Inst. Phys. Nuc!. Eng., Romania)
EICHLER Jorg
(Hahn-Meitner Inst. Berlin, Germany)
FAIFMAN Mark
(Russian Res. Cent., Kurchatov Inst. , Russia)
FUJIMA Kazumi Ri Fa' - ~ (Fac. Eng., Yamanashi Univ.)

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307

'*

HARA Shunsuke
1~ 11'(Dept. Gen. Ed., Tsukuba CoIl. Techno!.)HATTORI Toshiyuki m~ ~~ 1~ $(Res. Lab. Nucl. React., Tokyo Inst. Technol.)(Inst. App!. Phys., Univ. Tsukuba)
HINO Ken-ichi B If 1l HITACHI Akira fj ill :!l! (Kochi Med. Sch.)
HULDT Sven
(Lund Univ., Sweden)
HUTTON RogerICHIMURA Atsushi rTf t-t ?¥ (Inst. Space Astr. Sci.)
ICHIOKA Toshiyasu rTf IUU flJ ~ (Grad. Sch. Arts Sci., Univ. Tokyo)
IGARASHI Akinori .li+oo)3)HIIJ (Fac. Eng., Miyazaki Univ.)
IKEDA Hiroshi 7th ill tf (Univ. Tsukuba)
ISHII Keishi 15 # ~ Z (Fac. Sci. Eng., Ritsumeikan Univ.)
ISHIKAWA Norito 15 111 1t A (JAERI, Tokai Res. Estab.)
ITOH Akio 1ll" Ji. l* ~ (Fac. Eng. , Kyoto Univ.)
ITOH Yoh fit Ji. 1% (Fac. Sci., Josai Univ.)
IWAI Yoshio :E # .&:t: (Grad. Sch. Arts Sci., Univ. Tokyo)
IWASE Akihiro :E iii ~ 7i: (JAERI, Tokai Res. Estab.)
KAGEYAMA Kensuke Ii ill fjt 11'- (Fac. Eng., Saitama Univ.)
KANEKO Shinichi ~ -f- ~ (Fac. Sci., Tokyo Inst. Techno!.)KAWATSURA Kiyoshi }II Iffi M (Fac. Eng. Design, Kyoto Inst. Techno!.)KHEIFETS Anatoli (Australian Nat!. Univ., Australia)ft ~(Fac. Eng., Kyoto Univ.)
KIMURA Kenji
KIMURA Mineo
ift ~ ~ (Sch. Allied Health Sci., Yamaguchi Univ.)
KITAJIMA Masashi ~r. 1f!b J§ 9:. (Fac. Sci. Techno!., Sophia U niv.)
KOBAYASHI Nobuo IJ'\ if* 1~:t: (Dept. Phys., Tokyo Metrop. Univ.)
KOIKE Fumihiro IJ'\ 7th X tf (Sch. Med., Kitasato Univ.)
KOIZUMI Tetsuo IJ'\ jjt :gr:t: (Dept. Phys., Rikkyo Univ.)
KOMAKI Ken-ichiro IJ'\tttM-f!~ (Grad. Sch. Arts Sci., Univ. Tokyo)
KOWARI Kenichi IJ'\ ~U ~ (Dept. Appl. Phys. Chern., Univ. Electro-Commun.)
KURODA Naoshi If. ill ~;:t, (JAERI, Tokai Res. Estab.)
KUROKI Kenro If.
~ f!~(Nat!. Res. Inst. Police Sci.)
MANN Ady(Phys. Dept., Israel Inst. Techno!., Israel)
MARTINSON Indrek (Dept. Phys., Univ. Lund, Sweden)(Dept. Pathol., Tokyo Med. Dent. Univ.)
MATSUO Takashi ;f~ tt.
MATSUZAWA Michio t;} if im ~ (Dept. Appl. Phys. Chern., Univ. Electro-Commun.)
MITAMURA Tohru ='illft frIt (Fac. Eng., Himeji Inst. Techno!.)MITSUKE Koichiro J!j)ft4-f!~ (Inst. Mol. Sci.)
MIZOGAWA Tatsumi i1f.)l1 JJX E (Nagaoka CoIl. Technol.)
MO HRI Akihiro ~ flJ 1¥1 tf
MUKOYAMA Takeshi [tiJ LlJ ~ (Inst. Chern. Res., Kyoto Univ.)
NISHIDA Nobuhiko ID3 ill f"§"& (Fac. Sci., Tokyo Inst. Techno!.)NISHIMURA Tamio ID3 ft .§:; ~OHTANI Shunsuke~ f~ 11'(Inst. Laser Sci., Univ. Electro-Commun.)
OKADA Kunihiro IUU ill ~~ 7i: (Fac. Sci. Tech., Sophia Univ.)
OKAYASU Satoru IUU 1i: fB- (JAERI, Tokai Res. Estab.)
OKUNO Kazuhiko ~ If fD"& (Dept. Phys., Tokyo Metrop. Univ.)
ONO Fumihisa IJ'\ If )c J\ (Dept. Phys., Okayama Univ.)
OSHIMA Nagayasu
1f!b 71<
SAKAI Akio :t& # BB:t: (Vacuum Products Co.)
SAKATA Hideaki :t& ill "!If I3jJ (Fac. Sci., Tokyo Inst. Technol.)
SATO Hiroshi 1t Ii i1!f 9:. (Fac. Sci., Ochanomizu Univ.)
SATOH Kazuhiko 1t Ii -"& (Fac. Sci., Tokyo Inst. Technol.)
SHIMA Kunihiro li!J ~~ tf (Tandem Accel. Cen., Univ. Tsukuba)
SHIMAKURA Noriyuki li!J ~ ;f-2. Z (Fac. Sci., Niigata Univ.)
SOEJIMA Kouichi ~Jj li!J i1!f (Fac. Sci., Niigata Univ.)
TAKEKAWA Michiya
JII Ji t!1
TERANISHI Yoshiaki ~ ~ ~ 19"
TERASAWA Mititaka ~ if ffil 4(Fac. Eng., Himeji Inst. Technol.)

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THURlEZ Sebastien
TONUMA Tadao p
iE:li1 (Adv. Res. Inst. Sci. Eng., Waseda Univ.)(Inst. Appl. Phys., Univ. Tsukuba)
TOSHIMA Nobuyuki p ~~ 1~
TRIKALINOS Christos(Univ. Athens, Greece)
TSUCHIDA Hidetsugu ± E8 *:.j( (Fac. Sci., Nara Women's Univ.)
UEDA Kiyoshi 1: E8 i~ (Res. Inst. Sci. Meas., Tohoku Univ.)
WAKIYA Kazuyoshi n~ ~ - ~ (Fac. Sci. Technol., Sophia Univ.)
WATANABE Shinichi rOC :i2l1~ (Dept. Appl. Phys. Chern., Univ. Electro-Commun.)
YAGISHITA Akira t~n T
Bjj
(KEK)
ZOU Yarning (Shanghai Jiao Tong Univ., China)m*

Trainees
BOYD Micah (Dept. Phys., Univ. Lund, Sweden)
ENDO Atsumi :ii Ai if- ~ (Dept. Phys. , Grad. Sch. Sci., Univ. Tokyo)
HASEGAWA Tadayuki -Ef~JlU1'.Z (Grad. Sch. Eng., Tokai Univ.)
HORI Masaki #m iE fit (Dept. Phys., Grad. Sch. Sci., Univ. Tokyo)
HOSHINO Masamitsu £ lff iE 7t (Fac. Sci. Technol., Sophia Univ.)
IIDA Ryouichi
E8 ~ (Univ. Electro-Commun.)
ITO Akira fft ni Wt (Dept. Phys., Rikkyo Univ.)
ITO Takaomi fft Iii 1% ~ (Grad. Sch. Arts Sci., Univ. Tokyo)
KAMEl Takehito ~ it
1= (Fac. Sci. Technol., Sophia Univ.)
MAJIMA Takuya ra, ~,~ 1:.0 ill (Fac. Eng., Kyoto Univ.)
MATSUSHIMA Hiroshi t~ ~ rt (Dept. Phys., Grad. Sch. Sci., Univ. Tokyo)
MORISHITA Yuichiro ~Til-~~ (Dept. Phys., Grad. Sch. Sci., Univ. Tokyo)
MURAKOSHI Dai tt ~(Grad. Sch. Arts Sci., Univ. Tokyo)
NAKAMURA Takashi ~ tt • it (Univ. Electro-Commun.)
OGURA Kunihiro ;j'\ ~ t~ 7i (Fac. Sci. Technol., Sophia Univ.)~Ij ~(Grad. Sch. Arts Sci., Univ. Tokyo)
OKABAYASHI Norio fifiJ
OKADA Shinichi fifiJ E8 ~ (Fac. Sci. Technol., Sophia Univ.)
OONO Takayuki
lff ~i Z (Fac. Sci. Technol., Sophia Univ.)
TAGUCHI Yoshio EB 0 ~:lil (Fac. Sci., Tokyo Inst. Technol.)
TAKABAYASHI Yuichi ;§'j;ft iit -- (Dept. Phys., Grad. Sch. Sci., Univ. Tokyo)
TAKAHASHI Takehisa ;§'j:m m: % (Dept. Phys., Rikkyo Univ.)
YAMASHITA Kenya ill T If ~ (Dept. Phys., Grad. Sch. Sci., Univ. Tokyo)

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Head

NAGAMINE Kanetadalk ~ ~ I~'

Members
ISHIDA Katsuhiko E EEl Jm
MATSUDA Yasuyuki t~ E8 ~NAKAMURA Satoshi N. ~ tt
YAGI Eiichi )\
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MATSUZAKI Teiichiro f~~tjtm ~~WATANABE Isao rOC it J}] ift

Visiting Members and Postdoctoral Fellows
AKIMlTSU Jun ~* 7t ~ (ColI. Sci. Eng., Aoyama Gakuin Univ.)
AKIMOTO Katsuhiro ~*~ r$(lnst. Mater., Univ. Tsukuba)
ARAl Juichiro *Jfit~-~~ (Sci. Univ. Tokyo)
ASAl Kichizo ~~ it ~ Ii (Univ. Electro-Commun.)
BAKULE Pavel
DAS Prasad Tara
(Dept. Phys., State Univ. New York, Albany, USA)
FUKAYA Atsuko i* ~ ~±HASHI Kenjiro ffl $=~~HASHIMOTO Masashi :m~ 9:. (JAERl, Tokai Res. Estab.)

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HIGEMOTO Wataru n~
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HIYAMA Emiko n~ ill ~~r
ITO Atsuko 1ft~
IWASAKI Masahiko E ~~ ~(Dept. Phys., Tokyo Inst. Technol.)
KADONO Ryosuke r~ H- N. ~ (KEK)
KATO Mineo 110 ~ ~ ~ (JAERI, Tokai Res. Estab.)
KAWAMURA Naritoshi ?riJ ft nX: •KINO Yasushi
If(Fac. Sci., Tohoku Univ.)
KOIKE Youji IJ" 7tl! i$(Fac. Eng., Tohoku Univ.)
KRISHNAMURTHY Vemuru
KUNO Yoshitaka ~ If N. 1f- (KEK)
KUROSAWA Kiyoyuki m. lR
1T (JAERI, Tokai Res. Estab.)
MACRAE Roderick M.
MARUYAMA Takahiro 1L ill ~1115- (Inst. Mater., Univ. Tsukuba)
MATSUSHITA Akira f~ T~
MEKATA Mamoru § 15 ;j: (Fac. Eng., Fukui Univ.)
tf (KEK)MIYAKE Yasuhiro -=: ~MIYAKO Yoshihito t~ f~ 1= (Fac. Sci., Osaka Univ.)
MOCHIKU Takashi
i% ± (Natl. Res. Inst. Metals)
MORITA Masato ~ 83 iE A (Fac. Sci., Josai Univ.)
MORITA Reiko ~ 83 ~ r(Josai Jr. ColI. Women)
NISHIDA Nobuhiko "@ EB 19(Fac. Sci., Tokyo Inst. Technol.)NISHIYAMA Kusuo "@ ill If ~ (KEK)
PRATT Francis L.
SAKAMOTO Shinichi :!& 5C ~ (KEK)
SATO Kazuhiko 1t ~ (Fac. Sci., Saitama Univ.)
SCHEUERMAN Robert
SHIMOMURA Koichiro Tfti~-e~ (KEK)
STRASSER Patrick
SUGAI Hiroyuki @[ J! 7i 1T (JAERI, Tokai Res. Estab.)
TAKABATAKE Toshiro ~ ~ fit e~ (Grad. Sch. Adv. Sci. Matter, Hiroshima Univ.)
TAKIGAWA Masashi ~~ JII 1= (Inst. Solid State Phys.)TANASE Masakazu 1M. iE fD (JAERI, Tokai Res. Estab.)
TORIKAI Eiko ,~. ~(Fac. Eng., Yamanashi Univ.)
UEDA Kazuo J:. EB fo ~ (Inst. Solid State Phys.)
UMEO Kazunori f~ ~ fD J'llj (Fac. Sci., Hiroshima Univ.)
WADA Nobuo fo EB 19 til (Grad. Sch. Arts Sci., Univ. Tokyo)
WATANABE Tsutomu Vi!~ 1J (Int. Chr. Univ.)m r** '*;t:=

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OHIRA Seikoif ~ r(Grad. Sch., Univ. Tokyo)
TANAKA Hiroyuki EB $ 7i ¥(Grad. Sch., Nagoya Univ.)
TOYODA Akihisa
83 :Jb ~ (Grad. Sch., Univ. Tokyo)"*.aMagnetic Materials Laboratory

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Head
KATSUMATA Koichi~ X ffft. -Members
HAGIWARA Masayuki~ JJjt 1&¥

MATSUDA Masaaki

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Head
KATAYAMA Takeshi

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AMEMIYA Hiroshi
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NAKAMURA Masato ~ tt 1= if
TAMBA Moritake
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HAMAG AKI Manabui~!~~
OKAZAKI Kiyohiko
IilUm~iff lttJ
YANO Katsuki
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Visiting Members and Postdoctoral Fellows
CHOUFFANI Khalid
TAKEUCHI Takeshi
tT r*J ~~YUN Chong-Cheoul
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Cellular and Molecular Biology Laboratory

Head
SHIBATA TakehikoMembers
LING Feng~~ E8 fElt

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Visiting Members and Postdoctoral Fellows
YOSHIMASU Masatoshi E ~ ~ 13i:

Cellular Physiology Laboratory
Head

HANAOKA Furnio

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Members
KITAYAMA Shigeru~t LiJinYATAGAI Furnio~E8Jt)(::K

Visiting Members and Postdoctoral Fellows
ANDO Koichi ~ Hi ~ (N atl. Inst. Radiol. Sci.)
FURUSAWA Yoshiya tJ i'1t -tQ (Natl. Inst. Radiol. Sci.)
HAMA Yoshirnasa i~ ~ J§ (Sci. Eng. Res. Lab., Waseda Univ.)
HASE Yoshihiro 1f ~ ;{iit! 7i; (JAERI, Takasaki Rad. Chern. Res. Estab.)
HOSHINO Kazuo £ ff (Natl. Inst. Radiol. Sci.)
ITO Hisao W ~:t: (Sch. Med., Chiba Univ.)
ITSUKAI CHI Hirorni 1i B TIH} -0 J}. (N at I. Inst. Radiol. Sci.)
KANAI Tatsuaki i: # Ji 13)3 (Natl. Inst. Radiol. Sci.)
KASAl Kiyorni jt: # iff ~ (N at I. Inst. Radiol. Sci.)
KAWACHI Kiyornitsu iPJ r*J iff Jt (Natl. Inst. Radiol. Sci.)
KOBAYASHI Yasuhiko IJ\~(JAERI, Takasaki Rad. Chern. Res. Estab.)
MATSUFU JI N aruhiro 1~ Ji nX: 51. (N atl. Inst. Radiol. Sci.)MINOHARA Shinichi ~ mt 1$ (Natl. Inst. Radiol. Sci.)
MURAKAMI Masahiro tt 1: lE 51. (Natl. Inst. Radiol. Sci.)
SAITO Mizuho 1f Hi fffij:f,! (N at I. Inst. Radiol. Sci.)
SASAKI Hiroshi {t4* 51. (Fac. Med., Kyushu Univ.)
SHIKAZONO Naoya J1[ III ~ ~ (JAERI, Takasaki Rad. Chern. Res. Estab.)
SOGA Furninori ~ ft )( g
(Inst. Nucl. Study, Univ. Tokyo)
TANAKA Atsushi E8 ~ ?¥ (JAERI, Takasaki Rad. Chern. Res. Estab.)
TOMURA Hirorni ji- 1-t 1-i5- ~ (Natl. Inst. Radiol. Sci.)
WATANABE Masarni ioc illlE ~ (Fac. Pharm., Nagasaki Univ.)
YAMASHITA Shoji LiJ T J§
(Natl. Saitama Hospital)

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LI Ryonpha

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Plant FUnctions Laboratory
Head
YOSHIDA Shigeo ~ B3 1f. ~Members
ABE Tornoko~ilJ ~~ *tJ -=f

MATSUYAMA TornokitJ} ill ~o 1M

Visiting Members and Postdoctoral Fellows
HARA Yasuhide mt y~!Ji; (Kanagawa Inst. Agric . Sci.)/$: ~l (Dept. Biosci., NAIST)HASHIMOTO Takashi
KITAURA Takeo ~t ilfl ~ ~ (Kanagawa Inst. Agric. Sci.)
KIU CHI Reikor*J ~ -=fMIYAGAI Mashu '8 j} Iff mJ
MIYOSHI Kazurnitsu -= ~ - -Jt (Fac. Bioresource Sci., Akita Pref. Univ.)
SATO Furnihiko 11: Ri X ~ (Dept. Agric. Chern., Kyoto Univ.)
SATO Shinobu 11: Ri ?]. (Inst. BioI. Sci., Tsukuba Univ.)Jf - (Suntory Ltd.)SUZUKI Kenichi JfJ

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KOMOMI Yuki ff ~ 1tJ if.[. (Fac. Sci. Tech., Sci. Univ. Tokyo)
TAKAHASHI Hideki ~:m!Ji; 1M (ColI. Agric. Vet. Med. , Nihon Univ.)

Microbial Toxicology Laboratory
Head
YAMAGUCHI Isarnu ill 0~
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ARIE Tsutornu

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NOSE Yasuhiro ~~ ~~SOSHI Takayuki ~ JIIi ~l 1T

CYCLOTRON CENTER
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YANO Yasushige
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YANO Yasushige

Members
IKEGAMI Kurnio
7t!!L1L = ~KAMIGAITO Osarnu
L:tiIj1-fl~OHNISHI Jun-ichi
i!:!3 ~ OTAKE Masao
it 1& 41TANABE Toshiya
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Visiting Members and Postdoctoral Fellows
AKIYOSHI Hirornichi
l:k ~ § 1C

312

INABE Naohito
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KUBO Toshiyuki~ 1~ ~ ¥OKUNO Hiroki~ ~ rt :fi:t
SAKAMOTO Naruhiko~ /$: nX: ~WAKASUGI Masanori~ ;f~ J§ re

AMANO Ryohei
7( ti' .& -0/(Fac. Med., Kanazawa Univ.)
ARAKAWA Kazuom)II lo ~ (JAERI , Takasaki Rad. Chern. Res. Estab.)
BATYGIN Yuri
BHATTACHARJEE Sudeep
CHATTOPADHYAY Subrata(Variable Energy Cycl. Cen., India)~ flj ~CHIBA Toshiya
CHIBA Yoshiaki~ ~t ElJ3DIAO Xungang
DINH DANG Nguyen
ENDO Kazutoyo
J! ~ fo -=- (Showa ColI. Pharm. Sci.)
FUJINAWA Tadashi~~(Mitsubishi Electric Co., Ltd.)
FUJIOKA Tsutomu~ Ii.ITJ$@(Toshiba Corp.)
FUJISAWA Takashi~ ¥R ~ it:(N.LR.S.)FUJISHIMA Shiro~ ~ 9: fm(LH.L)~~ E8 7t 1i(JAERI, Takasaki Rad. Chern. Res. Estab.)FUKUDA Mitsuhiro
FUKUNISHI Nobuhisa~~"@ ~ fi6
HEMMI Masatake~ J! i& if\:
HIMENO Seiichiro~~ffIDit-f!~(Sch. Pharm. Sci., Kitasato Univ.)
ftllJJ~~-r(Toshiba Corp.)
HIRUMACHI Tamiko
HONMA Toshihiro
ra~ %: J1:(N.LR.S.)
INAGE Hiroko
fill::f J! -=r- (Int. Life Sci. Inst., Showa Women's Univ.)
IN AMURA Takashi T.
fill ft ¥IWASA Naohito:5 ftc I[ 1=
KAWAGUCHI Takeo
111 0 if\: ~ (Mitsubishi Electric Co., Ltd.)KIDERA Masanori~ lE ~KIM Jong-Won
K 0 HAMA Akihisa'J, iJ: if :R:
KOZU Hideo
1$ i$: #i: t.ft (Toshiba Corp.)
MADOKORO Hideki
Fa' pJT ~ 1Y:t
MASUOKA Toshikatu~ Ii.ITJ 1~ ~(Hitachi Zosen Corp.)
MATSUMOTO Ken-ichiro
tl*Mrt-f!~(Showa ColI. Pharm. Sci.)
MATSUSHITA Akira f2- T
ElJ3(NASDA)MINAI Yoshitaka~ ~ 1! -2f.
(Cen. Art. Sci., Musashi Univ.)
MINAMI Takeshi
1¥J if\: it (Dept. Living Sci., Kinki Univ., Toyo-Oka Jr. CoIl.)
MIRONOV Vladmir(J.LN.R., Dubna, Russia)
MITSUMOTO Toshinori
1~ ~(Sumitomo Heavy Ind., Ltd.)g ¥R 1! fi&
MIYAZAWA Yoshitoshi
MORIKAWA Tetsuya~ )II ~ t!1
MOTONAGA Shoushichi
5C jK BH -t
NAGAFUCHI Teruyasu
71< ?~u p.~(Toshiba Corp.)
NAKANISHI Yukiko$"@ffi$-=r- (Int. Life Sci. Inst., Showa Women's Univ.)
NUMURA Masanobu*Jf ft iE f8"
NODA Koji
ti' E8 fjj: P] (N.LR.S.)
OGURA Yasumitsu'J" ;fJjt 7t (Fac. Pharm. Sci., Chiba Univ.)
OHKAWA Tomohiro
JII ~ 1i (Mitsubishi Res. Inst., Inc.)OHTOMO Kiyotaka
8:.. 1~ ~i (Sumitomo Heavy Ind., Ltd.)OKAMOTO Youichi
Ii.ITJ
if (Showa ColI. Pharm. Sci.)
OKAMURA Masahiro
IUiJ ft ~ 1i
OKUMURA Susumu~ ft:i1t (JAERI, Takasaki Rad. Chern. Res. Estab.)RIZAWA Takahito
flJ iR ~i A (Toshiba Corp.)
SAITO Fuminori
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SAKURAI Hiromu
t~ #~t.
(Kyoto Pharmaceutical Univ.)
SATOU Yoshiteru
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SEKINE Hirotaka~ fi ~J,. ~i
SHINOHARA Atsushi
1i JJR ~ (Res. Reactor Inst., Kyoto Univ.)
SIDORIN Anatoly(J.LN.R., Dubna, Russia)
SUGU Kazuo;f~ #- - ~(Osaka Vacuum, Ltd.)

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SUZUKI Hiroyuki
iiJ "51. 1-y (RI Res. Cen., Chiba Univ.)
SUZUKI Kazuo
iiJ *O;i( (Fac. Pharm. Sci., Chiba Univ.)
iiJ @: ~~SUZUKI Naoki
TAKAHASHI Masaaki~ tit 1£ BB(ColI. Agric., Osaka Pref. Univ.)
TAKAHASHI Yoshio~:fit ¥c(Fac. Sci., Hiroshima Univ.)
TAKANAKA Masao~ 1$ 1& t.l
TAKEDA Atsushi
m: EB JIf. PJ (Sch. Pharm. Sci., Shizuoka Univ.)
TAKEUCHI Suehiro
rr I*J rt (JAERI, Tokai Res. Estab.)
TANAKA Yasushi
EB 9=' 1~ it (Kyokuto Boeki Kaisha, Ltd.)TOMIMASU Takio~±~~%;i((Free Electrons Laser Res. Inst.)
TOMINAKA Toshiharu~ 9=' flJ is(Hitachi, Ltd.)~ iR 1£ A.
(KEK)
TOMIZAWA Masahito
L :!& f!.!j -=f
UESAKA Meiko
UESAKA Tomohiro
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WATANABE Ikuo
Vi ill. fl~ ~ (Toshiba Corp.)
iJi :ill 1$ (Cen. Nucl. Study, Grad. Sch. Sci., Univ. Tokyo)
WATANABE Shin-ichi
WU Dezhong(Scintia Sinica, China)
XIA Jia-Wen][ 1* X (Inst. Modern Phys., Academia Sinica, China)
YAMASAKI Mineo
LlJ 1lI~ Ill!;i( (Nara Med. Univ.)7]( IDiX: A(Fac. Sci., Shizuoka Univ.)
YANAGA Makoto
YANG Youg Feng
(Scintia Sinica, China)
YASUI Hiroyuki
1i it ttl- Z (Kyoto Pharmaceutical Univ.)
YOKOUCHI Shigeru
fft I*J tt (Osaka Vacuum, Ltd.)fft LlJ - e~
YOKOYAMA Ichiro
YONEDA Akira
EB ~YOSHIDA Yutaka~ EB~(Shizuoka Inst. Sci. Tech.)

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ARIGA Takehiro'*i ~ 1@ tf (Fac. Sci., Toho Univ.)
FUGONO Jun
if lff *'1! (Kyoto Pharm. Univ.)
n+.oo.W~(Int. Life Sci. Inst., Showa Women's Univ.)
IGARASHI Kaori:5 rEI' £ ~JlI (Fac. Sci., Shizuoka Univ.)
IWAMA Motonori
IJ,jJt~*O-=f(Int. Life Sci. Inst., Showa Women's Univ.)
KOIZUMI Miwako
KURITA Tetsuro~ EB 13" e~(Inst. Phys. , Univ. Tsukuba)
MAETSU Hitomi
lW i4t 1= ~ (Fac. Sci., Shizuoka Univ.)
OHNISHI Tetsuya"@ =m ~
(Fac. Sci., Univ. Tokyo)
LlJ ro {Q (Fac. Sci., Shizuoka Univ.)
OHYAMA Takuya
IJ'{~(Coll. Sci., Rikkyo Univ.)
OZAWA Shuichi
SEKIGUCHI Kimiko~ 0(Dept. Phys., Grad. Sch. Sci., Univ. Tokyo)
SHIOBARA Yamato
ij[(Fac. Pharm. Sci., Chiba Univ.)¥~ lff 1~(Kyoto Pharm. Univ.)
TAKINO Toshikazu
r*J LlJ 115- it (Inst. Phys., Univ. Tsukuba)
UCHIYAMA Koji
XIAO Meiqin~~ ~(Cen. Nucl. Study, Grad. Sch. Sci., Univ. Tokyo)
YOSHIDA Shozo~ EB BB :=(Nara Med. Univ.)
YOSHIDA Tsutomu~ EB"M (Fac. Sci., Shizuoka Univ.)**
7*'* *1=::r*0*0Beam Technology DivisionHead
YAN 0 Yasushige
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FU JIMAKI Masaki
Ji ~ 1£ tjt
FUJITA Shin
Ji EB *If
IKEZAWA Eiji
?ill iR ~KAGEYAMA Masashi
J3 LlJ 1£
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Hi EB e~GOTO Akira
1& Hi ,;ITO Sachiko
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KASE Masayuki
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IVJ ill ~~NAGASE Makoto
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NAKAJIMA Shunji !f1 ~ ~~USHIDA Kiminori:fr ill i~ m
YAMAJI Shuhei
III ~ 1~ ~=MORITA Kosuke~ EB i! 1r
NAKAGAWA Takahide!f1)1I"4 3%
OGIWARA Kiyoshi~it
WADA Takeshi
EB
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ABE Yasuhisa ~iiJ:g:~ ~)... (Yukawa Inst. Theor. Phys. , Kyoto Univ.)
ABURAYA Takashi ¥B:! ~it- (NASDA)
ANZAWA Osamu 1;: iR 1~ (NASDA)
P] Em(NASDA)AOKI Jiro W
J1: (N ASDA)
AOYAMA Kazuhiro W ill
ARIMA Akito :;ff.~ t'~ A (Former President, RIKEN)
ARITOMO Yoshihiro :;ff 0:.
i! (J.I.N.R., Dubna, Russia)
BABA Shinji .~ jli {~* (NASDA)
BAN Syuichi f$ 3% (KEK)
BHATTACHARYA Sankar(Variable Energy Cycl. Cen., India)
CHAKRABARTI Alok
(Variable Energy Cycl. Cen., India)
DATE Schin W Jt {$ (J ASRI)
DENISOV Vitali(J.I.N.R., Dubna, Russia)
EJIRI Hiroyasu iI JK~(RCNP, Osaka Univ.)
FUJIOKA Manabu Hi fRij ~ (Cycl. Radioisot. Cen., Tohoku Univ.)
FUJITA Yoshitaka Ii ill {! 1f. (Fac. Sci., Osaka Univ.)
FUJIWARA Ichiro ~~~(Dept. Economy, Otemon Gakuin)
FUJIWARA Mamoru JJi~(RCNP, Osaka Univ.)
FURUNO Kohei ~ ff J!. 3f (Inst. Phys., Univ. Tsukuba)
FURUSE Kaoru ~ 7ii ~ (NASDA)
FUTAMI Yasuyuki
J! ~ Z(N .I.R.S.)
GOKA Tateo Ji
JI::K (NASDA)(I.M.S.)
HAMA Hiroyuki i~ It ¥HARADA Toru
ill ~~ (Fac. Social Inf., Sapporo Gakuin Univ.)it (Fac. Sci., Tohoku Univ.)
HASHIMOTO Osamu
HATANAKA Kichiji :J:m!f1 E it (RCNP, Osaka Univ.)(JAERI, Tokai Res. Estab.)
HATSUKAWA Yuichi :fJJ)l1
HATTORI Toshiyuki ~Ii:g:~ f$: =¥ (Res. Lab. Nucl. React., T .I.T.)
HAYANO Ryugo S. !f. ff ff~ Ji (Fac. Sci., Univ. Tokyo)
HIEDA Kohtaro tw{1:7t*~~ (CoIl. Sci., Rikkyo Univ.)
HIGUCHI Tatsuro tim 0 J! e~ (NASDA)
HIRAO Yasuo ~ ~ ~ ~ (N.I.R.S.)HIROSE Takayuki rt. ~ "4 ¥(NASDA)ra, ~ til (Cen. Mathe. Sci., Univ. Aizu)
HONMA Michio
HORIBATA Takatoshi #ill !iNti 1f. 13t (Fac. Eng. , Aomori Univ.)
HORIGUCHI Takayoshi W1 0 ~l A (Dept. Clinical Rad., Hiroshima Int. Univ.)
HORIUCHI Hisashi W1 I*J 7N! (Grad. Sch. Sci., Kyoto Univ.)
HOSONO Kazuhiko *HI ff
1ft (Dept. Eng. Sci., Himeji Inst. Tech.)
HYODO Toshio ~ ~j f$:::K (Grad. Sch. Arts Sci., Univ. Tokyo)
IDESAWA Masanori tl:1?, iE f.!f, (Univ. Electro-Commun.)
IGARASHI Toshio Ji+oo.1i&a (NASDA)
IKEDA Akitsu 7fu EB ~)c if (Shizuoka Inst. Sci. Tech.)
IKEDA Nobuo 7fu EB {$ ::K(Fac. Sci., Kyushu Univ.)
IKEZOE Hiroshi 7fu i~ tw: (JAERI, Tokai Res. Estab.)(Fac. Sci., Kyoto Univ.)
IMAI Kenichi ~:#IMAMURA Mineo ~ fttil (National Museum of Japanese History)
INOUE Makoto :#- L
1~(Res. Reactor Inst., Kyoto Univ.)
ISHIZUKA Takeo 15 ~~(Fac. Sci., Saitama Univ.)
ITO Yasuo 1fT li~(Atomic Energy Res. Cen., Univ. Tokyo)
ITOH Kazuya 1fT ~-ill. (Tandem Accel. Cen. , Univ. Tsukuba)

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ITOH Yoshiko {]I"
7i -=f (Adv. Res. Inst. Sci. Eng., Waseda Univ.)
ITOH Yutaka {]I" iii Jt (KEK)
IVANYUK Fedir(Inst. Nucl. Res., Ukraine)
IWAI Satoshi :E:j:j: fii.9:. (N uclear Development Co., Ltd)IWAMOTO Akira :E
BH (JAERI , Tokai Res. Estab.)
IWASHITA Yoshihisa :E T 7j ~ (Inst. Chem. Res., Kyoto Univ.)
IWATA Ren :E B3 ~* (Cycl. Radioisot. Cen. , Tohoku U niv.)
IZUMOTO Toshiaki jJt
flj ~ (ColI. Tourism., Rikkyo Univ.)
JEONG S. C. lIS ?~ ~ (KEK)
KAMIMURA Masayasu L ft lE(Fac. Sci., Kyushu Univ.)
KANAZAWA Mitsutaka i: 7R -Jt ~l (N.I.R.S.)
KANEKO Junichi i: -=f 1M! (JAERI, Takasaki Rad. Chem. Res. Estab.)
KATO Kiyoshi 1.10 iii ~ 7j (Fac. Sci., Hokkaido U niv.)
KATSURAGAWA Hidetsugu fl}ll:f;; oom (Fac. Sci., Toho Univ.)
KAWAZU Akira ?aJ if I&! (Techno Riken Co., Ltd.)KIM Eun Joo(Fac. Eng., Tohoku Univ.)
KIM Jaehong
KOBAYASHI-KOMIYAMA Misaki :ib LlJ ~ !!*KUBOYAMA Satoshi ~{~LlJ~~ (NASDA)
KUDO Hisaaki I iii ~ BE (Fac. Sci., Niigata Univ.)
KUMADA Masayuki 1f~ B3 ~ Z (N .I.R.S.){~(KEK)
KURIHARA Toshikazu ~LEE San-Mu
tEl(Inst. Phys., Univ. Tsukuba)
LI Hongling (RCAST, U niv. Tokyo)
MATSUDA Sumio f~ B3 1M! ~ (NASDA)
tiE ~ (Inst. Chem. Res. , Kyoto Univ.)
MATSUKI Seishi f~B)'t i$(NASDA)
MATSUMOTO Akihiro t~
MATSUSE Takehiro f~?fJi::st ¥1!f (Fac. Textile Sci. Tech., Shinshu Univ.)
MATSUYANAGI Kenichi f~ f~n -liJf (Grad. Sch. Sci., Kyoto Univ.)
MATSUZAKI Kazuhiro f~ ~~ - ¥1!f (NASDA)
MATSUZAKI Masayuki f~ ~~ ~ Z (Fac. Ed., Fukuoka Univ.)
MENG Jie(Peking Univ., China)
MINAMISONO Tadanori 1¥J ~ I~' ~Ij (Grad. Sch. Sci., Osaka Univ.)-tl1 (KEK)MIYATAKE Hiroari § m:
MIZUNO Yoshiyuki :7]( ~ ~ Z (RCNP, Osaka Univ.)
MIZUSAKI Takahiro :7]( ~~ ~ ¥1!f (Fac. Sci., Univ. Tokyo)
MORI Yoshiharu ~ ~ d; (KEK)MUKHOPADHYAY Tapan(Variable Energy Cycl. Cen., India)
MURAKAMI Hideoki ft L "!Ii:. ~ (Fac. Ed., Tokyo Gakugei Univ.)
MURAKAMI Tetsuya tt L =rg- -tl1 (Grad. Sch. Sci., Kyoto Univ.)
MUTA Atsushi
83 ?¥ (Inst. Phys., Univ. Tsukuba)
MUTO Kazuo m: ~ -:fti (Fac. Sci., T.I.T.)
NAGAI Yasuki 71<.:j:j:~t(RCNP, Osaka Univ.)
NAGAI Yuki 71<.:j:j: E8 {f.C (NASDA)
NAGASHIMA Yasuyuki :R ~.~ ~ Z (Grad. Sch. Arts ScL , Univ. Tokyo)
NAKADA Hitoshi ~ B3 1= (Fac. ScL, Chiba Univ.)
NAKAJIMA Hiroshi ~ Jffb 7i (JAERI, Takasaki Rad. Chem. Res. Estab.)
NAKAMURA Hiroyuki ~ ft 1ft Z(Kitakyushu Nat I. ColI. Tecnol.)
NAKAMURA Ichiro ~ ftfl~(Fac. Sci., Saitama Univ.)
NAKAMURA Takashi ~ ft ~ ~ (Cycl. Radioisot. Cen., Tohoku Univ.)
NAKAO Noriaki ~ ~ ~ a~ (KEK)
NEMOTO Norio fl
1J! ~ (NASDA)
NODA Akira ff B3 ~ (Inst. Chem. Res., Kyoto Univ.)
NOMURA Toru ff ft :!f (KEK, Tanashi)
NOZAKI Tadashi ff ~~ iE (Purex Co.)
OGAWA Kengo IJ\}lI}l:g- (Fac. ScL, Chiba Univ.)
if 1# (NASDA)
OHIRA Hideharu

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316

OHTA Kiyoshi -}.:::. 83 j~ (Fac. Sci., Saitama Univ.)
OHTSUKI Tsutomu#:1 in (Lab . Nucl. Sci. , Tohoku Univ.)
OHYA Jiroe~ (NASDA)
01 Makito *#7J*-cA (Dept. Phys., Grad. Sch. Sci., Univ. Tokyo)
OKAMOTO Hiromi 1m]
7i:. E (Grad. Sch. Adv. Sci. Matter, Hiroshima Univ.)
OKAMURA Hiroyuki 1m] ft "51. ~ (Fac. Sci., Saitama Univ.)
ONISHI Naoki
1m ~ ~ (Fac. Eng., Yamanashi Univ.)
OOTOMO Hiromitsu
1;:. i$ 7t (NASDA)OTSUKA Takaharu
j~ -4 is(Fac. Sci., Univ. Tokyo)
SAGARA Kenshi l§'& ~ ~ (Fac. Sci., Kyushu Univ.)
SAITO Motozo ~ Mi tJ.i1 =:SAKAI Hideyuki i~ +1= "?Ii:. iT (Dept. Phys., Grad. Sch. Sci., Univ. Tokyo)(Dept. Phys., Tohoku ColI. Pharm.)
SATO Ken-ichi 16: Mi ~ SATO Kenji 1t£ Mi f@(RCNP, Osaka Univ.)
SATO Osamu 13:: Hi :f-' (Mitsubishi Res. Inst., Inc.)
SATO Yukio 16: Hi ¥::K (N .I.R.S.)
SEKINE Toshiaki ~ ;fl1~ SA (JAERI, Takasaki Rad. Chern. Res. Estab.)
SHARMA Sumit(Pune Univ ., India)
SHENG Yeng Ching(Shanghai Inst. Nucl. Res., China)
SHIBATA Tokushi ~ EE ~ ,~, (KEK)
SHIMADA Osamu !f!b H3 {~ (NASDA)
SHIMIZU Akira 1~;7}( BB (RCNP, Osaka Univ.)
SHIMOMURA Koichiro Tft¥~-e~ (KEK)
SHIN Kazuo ~ *0 ~ (Fac. Eng., Kyoto Univ.)
SHINDO Hiroyuki $Jf Hi i~ Z (N ASDA)
SHINOZUKA Tsutomu ~ j~ ~ (Cycl. Radioisot. Cen., Tohoku Univ.)
SHIRAI Toshiyuki B +1= #i!l. Z (Inst. Chern. Res., Kyoto Univ.)
SHUGYOU Shinichi {~iT $Jf (NASDA)
SUEKI Keisuke~ 1r(Fac. Sci. , Tokyo Metrop. U niv.)
SUGAI Isao -g it ~ (KEK)
SUGAWARA-TANABE Kazuko 83 ill. *0 -=f (Otsuma Women's ColI.)
SUGIYAMA Hiroki lb LlJ~j(NASDA)SUMIYOSHI Hiroyuki 11 E rt iT (Matsusho-Gakuen Jr. ColI.)~~ tt(N ASDA)SUZUKI Takahiro ~iJ
SUZUKI Toshio ~iJ
1~ ~(ColI. Hum. Sci., Nihon Univ.)
SUZUKI Toshio ~iJ#i!l. ~ (Fac. Eng., Fukui Univ.)
SYRES SINE Evgueni(J.I.N.R., Dubna, Russia)
TAGISHI Yoshihiro H3 J¥ ~ 7i:. (Inst. Phys., Univ. Tsukuba)
TAJIMA Naoki IE ~,~ ~ 1M (Fac. Eng., Fukui U niv.)
TAKADA Masashi j!§'j H3 ~ ~ (N.I.R.S.)
TAKADA Norio J@j H3~(NASDA)
TAKAGI Syunji j@j
1~ is(Mitsubishi Res. Inst. , Inc.)
TAKAHASHI Takehide j@j 11 j: ~ (NASDA)
TAKEMASA Tadashi
1& jl- ± (Kyoto Univ. Ed.)
TAKIGAWA Noboru ~;)l1 ~ (Fac. Sci., Tohoku Univ.)
TAKIZAWA Yoshiyuki ?; if ~ ~TANABE Kosai H3 ill. -4 ~ (Fac. Sci., Saitama Univ.)
TANAKA Jinichi H3 I=fJ 1=(KEK)
TANAKA Kazuhiro EE I=fJ *0 JJi (Dept. Phys., Sch. Med., Jyuntendo Univ.)TANIKAWA Masashi ~ )11 MJ ~ (Fac. Sci., Univ. Tokyo)
TEZUKA Hirokazu =¥- j~ ?$ (Dept. Liberal Arts, Fac. Literature, Toyo Univ.)
TOHYAMA Mitsuru Ji LlJ if&] (Kyorin Univ.)
TOMITANI Takehiro ~ ~i~(N.I.R.S.)TOMODA Toshiaki 1;:. EE fiW. ~ (Fac. Eng., Aomori Univ.)
TORIYAMA Tamotsu ,~LlJ 1~ (Dept. Phys., Musashi Inst. Technol.)
TOYOKAWA Hiroyuki ~ )11 "51. ~ (Electrotechnical Lab., Agency Ind. Sci. Tech.)
TSUBAKI Noriyuki 11 ~Ij ¥(NASDA)

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317

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UEHARA Takashi .l.
li (Nuclear Development Co., Ltd.)URITANI Akira J.R B- iiI (Dept. Phys., Grad. Sch. Sci., Nagoya Univ.)
UTSUNOMIYA Hiroaki *~~g~LiiI (Fac. Sci., Konan Univ.)
VUONG Kim-Au(Inst. Physics-Hanoi-Vietnam, Vietnam)
WADA Ryoichi *0 EB .& (Texas A & M Univ. , USA)
WADA Takahiro *0 EB ~i 1i (Fac. Sci., Konan Univ.)
WAKAI Masamiti ~ if lE j}i (Grad. Sch. Sci., Osaka Univ.)
YABANA Kazuhiro
1t (Fac. Sci., Niigata Univ.)
YAMAZAKI Hirohito LlJ i1J~ J[ 1= (Lab. Nucl. Sci., Tohoku Univ.)
YOSHIDA Nobuaki E EB '§: iiI (Fac. Informatics, Kansai Univ.)
YOSHINAGA Naotaka E 7k raJ 1!f. (Fac. Sci., Saitama Univ.)
YOSHIOKA Yasuhiro 15 lUi]
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(NASDA)ZHAO Yuliang(Fac. Sci., Tokyo Metrop. Univ.)
ZHAO Yu MinZHOU Shan-Gui(Peking Univ., China)

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Trainees*

AOKI Yuka W
ill W (Fac. Sci., Tohoku Univ.)
ARIGA Takehiro /(f ~ iii! tf (Fac. Sci., Toho Univ.)
FU JISAKI Takashi hi i1J~ .. Z (ColI. Sci. , Rikkyo Univ.)
FU JITA Tatsuru hi EB }l (Fac. Sci., Kyushu Univ.)
HARUYAMA Seigo
LlJ ill::g. (Dept. Phys., Grad. Sch. Sci., Univ. Tokyo)
HIGURASHI Yoshihide 8 ~ :tf ~ (CoIl. Sci., Rikkyo Univ.)
IWASE Hiroshi :6 ~ rt (Fac. Sci., Tohoku Univ.)(Fac. Eng., Tohoku Univ.)
KIM Eun Joo
KOBORI Tomohiro IJ'\ #ttl ~ ~L (Fac. Sci., Saitama Univ.)
KURITA Tetsuro ~ E8 =rg- f,!~ (Inst. Phys., Univ. Tsukuba)
KUROSAWA Tadahiro ~~L(Grad. Sch. ScL, Tohoku Univ.)
NISHIKAWA Jun 1§ )11 ~ (Fac. Sci., Saitama Univ.)
NUNOMIYA Tomoya
g ~ ill (Fac. Sci., Tohoku Univ.)
OHNISHI Tetsuya
1!§' =rg- ~(Fac. Sci., Univ. Tokyo)
OKAMOTO Tomoko Wi.!:::$: ~D -f- (Fac. Sci. Tech., Sci. Univ. Tokyo)
OKUDA Hikaru ~ EB 7t (Fac. Sci., Kyushu Univ.)
OZAWA Shuichi IJ'\ i' 1~ (ColI. Sci., Rikkyo Univ.)
SASAKI Michiya ft4*J!!ill (Grad. Sch. Sci., Tohoku Univ.)
SATO Hisaki 1~ hi ~ wf (Fac. Eng., Tohoku Univ.)
SEKIGUCHI Kimiko ~ 0 1= -f- (Dept. Phys., Grad. Sch. Sci. , Univ. Tokyo)
SHIOMI Tomoyuki ifn ~it (Fac. Eng., Tohoku Univ.)
SUDA Kenji ~J{ EB ~ mi~ (Fac. ScL, Saitama Univ.)
TAGAYA Yu ~1JD~ :ft (Fac. Sci., Univ. Tokyo)
TANIGUCHI Shingo ~ 0 ~:g. (Grad. Sch. Sci., Tohoku Univ.)
TOKUNAGA Youji ~ 7k i$ d; (Grad. Sch. Eng., Osaka Univ.)
TSURUTA Kaoru ~ EB •(Interdisciplinary Grad. Sch. Eng. Sci. , Kyushu Univ.)
UCHIYAMA Koji I*J LlJ
it (Inst. Phys., Univ. Tsukuba)
UTSUNO Yutaka *t~ff fi (Fac. Sci., Univ. Tokyo)
WAKUI Takashi iffi #it (Fac. Sci., Tohoku Univ.)
XIAO Meiqin(Cen. Nucl. Study, Grad. Sch. Sci., Univ. Tokyo)
YAGITA Takanori }\*EB"~ (Interdisciplinary Grad. Sch. Eng. Sci., Kyushu Univ.)
YAMAMOTO Sumiko LlJ:::$: ~ -f- (Fac. Sci., Toho Univ.)
YASHIMA Hiroshi }\ lib(Fac. Eng., Tohoku Univ.)*

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Radioisotope Technology Division
Head
YATAGAI Fumio ~EBJ!-X=K

318

Visiting Members and Postdoctoral Fellows
ENOMOTO Shuichi II~
GO RDO N Alasdair
HIRUNUMA Rieko ~mflJiI-fKAGAWA Yasuhiro w)1Ii1i (Toray Res. Cen. Inc.)~
KATO Takesi 1m ni
KAWAMURA Yoshihiro JII ft J§ Jt
MAEZAWA Hiroshi -mr
tf (Fac. Med. Technol. , Tokushima Univ.)
Jf-fMORIMOTO Shigeko ~OGURA Koichi IJ, ~ Ml (ColI. Ind. Technol. , Nihon Univ.)
OZAKI Takuo ~ 1IJ~ ~ e~
TAMANO Haruna I mi¥JYANAGIYA Takahiro 19P ~ ~i 7i

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Trainees
INOUE Kensuke # J::
1r (Fac. Sci. Eng., Waseda Univ.)
KITO Masatoshi~j J§ flJ
(Fac. Sci. Eng., Waseda Univ.)
KUROBE Toshihiroj}~ flj tf(Fac. Sci. Eng., Waseda Univ.)(Fac. Sci. Eng., Waseda Univ.)
OKA Toshitaka ItliJ •* m. **ADVANCED ENGINEERING CENTER
Research Instruments Development Division
Head
SENOO Katsumi P* ~ 5le.

Members
IKEGAMI Yuji ?t!! J:: f,tJ ~NOMIYA Yoshio m- '8 7i W
SHIMODA Susumu ~ EE i1!
SUGAHARA Seigo 1f JJj( IE 1!r
TAKAHASHI Norikazu ~~!J WATANABE Tokuji Vi:ill f.&, is
YAMADA Yutaka LlJ EE ~m

KITS UN AI Tokuji f~ I*J f.&, ~SHIGA Tsunenobu ~ ~ -m 1~
SHIRAISHI Akira B:ti a~
TAJIMA Norio E8 ~ ~ ::t:URAl Teruo ?m # ~ ::t:
YAMADA Shogo LlJ E8 IE 1!rContracting Members
KANEKO Naoe ~ -f- ~ ~KUBO Ushizo 0-.1*:I:t TIl
MATSUMOTO Akira t~BB
NIIOKA Yuzo *fr ItliJ ~SASAMOTO Tetsuji:gr ~TAKAHASHI Kiyoji ~ tl1W
TOKIWA Saburo -m ~ :::: e~
YAMAMOTO Sumio LlJ
& it

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CHARACTERIZATION CENTER
Surface Characterization Division
Head
IWAKI Masaya -;filE ~*Members
NAKAO Aiko I=P ~ ~ -fYAGI Ei-ichi }\** -WATANABE Kowashi

iJi:ill

jlijjlj319

Visiting Members and Postdoctoral Fellows
KOBAYASHI Tomohiro IJ':f* *D i$

ADVANCED COMPUTING CENTER
Computational Science Division
Head
EBISUZAKI Toshikazu iX!IJ~ 1~ Members
IITAKA Toshiaki~ ~ fi! ~SUN OUCH I Kei

ifHz!*J §Visiting Members and Postdoctoral Fellows
MAKINO Yuko 4t If fii
MIURA Hitoshi:t5j
SHIMIZU Tetsuya ¥1lf£~ ill= imr*

BIOGENIC RESOURCES CENTER
Experimental Animal Research Division
Head
KUSAKABE Moriaki B "Tl}5~BB
Members
HIRAIWA Noriko
TSUKADA Teruyo-"¥:fi ~ -=f.±~ EE ~ it

IKE Fumio it!! 1i~ ~YOSHIKI Atsush fi*i~Visiting Members and Postdoctoral Fellows
KOGISO Aya IJ"*~ *3
KOJIMA Masayo IJ" $fb ~ it
KUBOTA Yukihiko )"'1¥EE$&
NORO Chikako !fg~DtJDr
POIRIER Christophe
YAMAGUCHI Hirotake ill 0 ~J,. ~YAMANOU CHI J yun ill Z!*J i~
YODA Yoshika
EE ~ W (Japan Sci. Technol. Corp.)*

Safety Center
Members
CHIBA Shigeo -f- ~ N. ~HARASAWA Kaoru JJj( iR ..
MATSUZAWA Yasuhide l~ if $:SHINOHARA Shigemi g JJj( N. C'..
YOSHIKI Hajime fi ~ ~"*FUKAZAWA Kunio i* iR 00 ;41
KAGAYA Satoru 1JD~...% 'I'!
MIYAGAWA Makoto g 111 ~ i§
UWAMINO Yoshitomo -.t:i: ~ m~

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320

i

AUTHOR INDEXABE Ryo~PJ:g:~~

4~PJ:g:~~-f-

ABE Tomoko

139, 140, 141~JJj{fIJJG

AIHARA Toshimitsu

7ff-*~*AKAGI Hiroyasu

6

AKOSHIMA Megumi ~PJ-f-~iJ <" h.
ALEKSEEV Igor 41, 170
ALLGOWER Chris

CORTINA Dolores

74

DESHPANDE Abhay

4

f*LlJfom 129
fKfi§7E 60, 63, 65, 66, 67

AKIYOSHI Hiromichi

41, 166

DEREVSCHIKOV Anatoly

f***PJ 161

AKIMOTO Keiji
AKIYAMA Kazuhiko

CIANCIOLO Vince

101

43

41,170DIAO Xungang

90,93,94

DIEHL Roland

32

MJi 1% 20, 21, 22, 23, 24

DINH DANG Nguyen

DO DANG Giu 25
DOSKOW Jack 41, 170
D UMITRIU Dana255

AMANO Ryohei:R!f .EFf

120, 128

EATON Gordon H.

51

AMBE Fumitoshi*:g:~Jtfit

93, 109, 129

ECCLESTON Roger S.

*ms~-f-

AMBE Shizuko*iii~IJ':::

ANDO Kozo

81, 82, 83

ANDO Yoshiaki*iii~!it

ANSARI Ahmad

22,27

AOI Nori

1!f#

AOKI Yuka~

1i.~e~A

ARIMA Akito

BAKULE Pavel13, 18, 20, 22, 23, 24

43

BENTZ Wolfgang

39

41, 170

iii~9:fm

FUJITA JiroiiiEE=~F>

FUJITA Shin

iiEE

74

~

265,266

FUJIWARA Hideki

iiJJj{~:ttt

60

FUKAYA Atsuko

i*~~-f-FUKUDA Naoki

mEEf!!:ttt 60, 68, 69, 70, 163

FULOP Zsolt

m~~;r-~lff~f68, 69, 70

GEISSEL Hans

74

16

GHAZIKHANIAN Vahe41, 168

GOKA Tateo

41, 168

CHIBA Toshiya+jj€flJ~

CHIBA Yoshiaki+jj€HElJ3 251

CHIMI Yasuhiro:9:IJ~"*~.L.

CHULKOV Leonid

74

197, 206, 210, 212, 224
87,89

43

1i~nt:RGOLOVKOV Mikhail

177,17872li}*~~-f-

GOMI Tomoko

41,43, 170

GONO Yasuyuki

60,63,65,66,67,68,69, 70~Rtj~zGORDON Alasdair

131, 142

GOSWAMI Ransana

72

GOTO Akira

144=-.t.¥I*J 68, 69, 70

GACSI Zoltan

BUCHER Damian

BUESCHING Henner

53, 54, 56

73~ii1t-t!1

BROWN B. Alex

BUNCE Gerry

131, 142, 148,230,243

60, 63, 65, 66, 67, 68, 72

FUTAKAMI Udai
41, 165

105

miffi~ro1

FURUSAWA Yoshiya

100

BROOKS Melynda L.

265,266

iiiJJj{~~FURUNO Kohei

72

212, 218, 220, 230

4

FUJIWARA Atsushi

FUKUSAKA Shoichi
200

72

BREHMER Sven

FIELDS Douglas E.

FUKUNISHI Nobuhisa

BORDEANU Cristina
BOYD Richard N.

129, 130, 193

FUJISHIMA Shiro

41,44

BHATTACHARJEE Sudeep
BOCHKAREV Oleg

111, 112, 113, 114, 116,
117, 118, 119, 120, 121,

78

43

BELIKOV Nikolai

114, 116~I*~-

FUGONO Jun ;§:!f *if!. 113
FUJIMAKI Masaki ii~lE:ttt 6, 193

41, 170

BAZILEVSKY Alexander~iifO~

ENDO Kazutoyo

10441, 168

BATURINE Vitaly

41, 43, 44, 166, 168, 172

122, 123, 125, 127, 128,

263

BATHE Stefan

21}!W~ A

80* 13tfr

BASSALLECK Bernd

EISENMAN Kaury

ENOMOTO Shuichi

41, 168

AZUMA Toshiyuki
BAI Mei 41, 43, 170

145

41, 170

161~PJrlt~~~:R

AWAGA Kunio

7ID-~#t~~138

1]

1i~fltf

ARIGA Takehiro

AWES Terry

57, 58

1iiI

EILERTS Scott
EN'YO Hideto

1!ff~P£~AOYAGI Shigenori
ARIE Tsutomu

60, 63, 65, 66

63, 65, 66, 67, 68, 69, 70

1!f;1q:tr~

100

EGUCHI-KASAI Kiyomi

129

43

130

f&ni ,; 4, 151, 152, 193, 197, 200, 206,

GOTO Yuji

f&Jiiat =208, 210, 212, 214, 216, 218,

HULDT Sven

220, 222, 224 , 226, 228; 230

HUTTON Roger

81,82,83,84

HYODO Toshio~~JH3t*33,41,43, 44, 168, 170, 172

GROSSE PERDEKAMP Matthias
GUNJI Shuichi

mp]fl~ -HACKE Marcus

97

HAHN Kevin Inshik

60

IGO George

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HAMADA Akira

i~83

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147

HANAOKA Fumio

Y~*

141

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HARUYAMA Seigo

ffi::~g~rfrtit

HASEBE Hiroo

41,172i*9='tJ(.w. 183
fEliftJxtit 131, 142, 146

LW-

10,174

6

ffi::~JII'if-

HASEGAWA Kenichi*

183:.tHI9='"EiiJ 56
ilt83lffil* 53, 154, 182

IMAI Ken'ichi~:ft.~-

41, 44, 166, 168, 170

1M AI Nobuaki~:ft.1$8jJ

63, 65, 67, 68, 69, 70:ft.Hf$1£ 119

IMURA Nobumasa

f;a:ill~A

ijlig~~$202

ISERI Yasunori

HAYAKAWA Kazuo.!f'-}lI-~

90,93,94,109

ISHIDA Katsuhiko

~Ji

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197, 206

ISHIDA Satoru::O83~~

48,49, 51, 107, 263::0 83 'I! 56::0 83 fi!ij lr 106::OLW-1£~

ISHIHARA Masayasu

41, 60, 63, 65, 66 , 67,

208

f~*

HIGEMOTO Wataru

4, 80, 249

41, 168#ff,**-1t 9

ISHIDA Takayuki

B WH~-

4, 208, 212, 222, 226, 228

nhrR*= 6, 193, 206

HATTORI Toshiyuki

HEMMI Masatake
HIASA Toshikazu

11

nhJ:JL-=~IKEGAMI Kumio

INABE Naohito

74

tw: 88, 187

IKEZAWA Eiji

IPPOLITOV Mikhail** ml{lt 33,41,43,44,46 , 166, 172

121

148

nh831~~

IKEDA Kiyomi

HATANO Michio

HELLSTROM Margarett

41,43,56, 166, 172:ft.JE(Jl-r 144

IKE Fumio illi fl~*
IKEDA Hiroshi nh83

HATANAKA Kichiji

HAYASHI Naoki

95, 151, 152, 188
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IHARA Noriko

76

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HAMANAKA Hiromi

ICHIHARA Takashi

IEKI Kazuo ~VAX;5fO
65
IGARASHI Kaori 11+i,W~

158

HAMA Yoshimasa

HARA Yasuhide

43

81,82,83g

68 , 69, 70, 166, 170
49, 102, 103

t;mDJt:;;: 185
HIGURASHI Yoshihide B iHf* 60, 63, 65, 66, 67, 68,
HIGUCHI Hiroyoshi

69, 70, 197

EJilitA 87,88,89
ISHIKAWA Souichi EJIIH- 9
ISHIKAWA Norito

ISHIZUKA Takeo ::o:t~m:~ 161
ISSHIKI Hiroshi -~ it 4

HIRAI Masaaki

f&ffi:mlz 11
1frJi:[0.* 144
ITO Sachiko 1friitf-r 243, 265, 266

HIRAI Masanori

ITO Takaomi

HILLEBRANDT Wolfgang

ITAGAKI Naoyuki

32

YIl~IDit-~~

HIMENO Seiichiro

119

f#1£EjJ 60,63, 65, 66
f# 1£*2. 33
HIRAIWA Noriko f:fi:!J4.-r 148
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HIRATA Kazuto

ITO Hisao

ITOH Akio

1¥ii~~f¥iif:k~102

ITOH Kazuya S.

r.tllJt~$

91

ITOH Yoshiko

HIROSE Toshirou

r.tllJtf;j!{~J.I

161

ITSUKAICHI Hiromi

ftlllJ~~-r

238

IVANOV Marian

118, 121IWAKI Masaya:fi*1£~IWAMA Motonori:firB'£~HI 118:fi1tr:ml1= 59, 60, 63, 65, 66, 67, 68, 69,~

60

HOMMA Takayuki*rB'~iz

4

IWASA Naohito

HONMA Michio *rB,iE!tit 15,16,17,174
HORIBATA Takatoshi ;m~~{3t 27j},fi83~i$

HOTTA Tomohiro
HUANG Haixin

41, 43, 170

HUGHES Vernon

41 , 170

HUI Qin
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99

74

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0.71<.

;m}IItw:Iffl~-mlt 1:> J.;. 145

IWAI Yoshio

HISANAGA Isamu£~ IE7\:11 B

Ill , 113, 114, 116, 117,

ftmflJiI-r

HOSHINO Masamitsu

9, 53, 54, 55, 56, 153

ffr*7f-r 95, 151 , 152

HIRUNUMA Rieko

HORIKAWA Hirotsugu

79

ffrJii5fo-ti!

HIROSE Takayuki

HIRUMACHI Tamiko

78

192

186

70

IWASAKI Hironori:fii/J~~1-:!J4.

IWASAKI Masahiko:fii/J~~~

33
85

60, 63, 65, 66, 67, 68, 69,
70:fi~';~IWASE Akihiro
IWATA Yoshiyuki
JANIK Rudo:fi83{3~z74

JANKA Hans-Thomas

32

48

87, 88, 89, 90, 187
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J 0 H Tetsuo

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KITANO Takahiro~tlff~:l:102

KITAO Kensuke~~~~IlJJ,195

iiLlJ1lk 86
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KITAURA Takeo~timit~141

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