ISSN 0289-842X

RIKEN
Accelerator
Progress Report
vol.

32

理化学研究所

The Institute of Physical and Chemical Research (RIKEN)RIKEN Accelerator Progress Report i1 (Q) (Q) (6)January.December UfI fI (Q)voL

32

I~ it. ~ ~ff ~ jiJT

The Institute of Physical and Chemical Research (RIKEN)
Wako, Saitama, 3S1.0198 JAPANEditors

T. AbeA. GotoT. Ichihara

K. Ishida

T. Kambara

Y. Kobayashi

A. Ozawa

1. Shimamura

S. Yamaji

Y. Yamazaki

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

CONTENTS
Page
1

I.

PREFACEII.

OPERATION OF ACCELERATORSRILAC Operation ..................................................................

3

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

5

The Tandem Operation

7

III.

RESEARCH ACTIVITIES

1.

Nuclear Physics

Structure of N

f'..J

20 Unstable Nuclei Studied by Monte Carlo Shell Model

9

Monte Carlo Shell Model Calculation and Computers.. . .... .......... ..... ... ... ....

10

Relativistic Continuum Hartree-Bogoliubov Theory with Both Zero Rangeand Finite Range Gogny Force and Their Application ...............................

11

The Proton and Neutron Distributions in Na Isotopes: The Development of Haloand Shell Structure .................................................................

12

A Giant Halo at the Neutron Drip Line .............................................

13

Landau-Migdal Parameters, 9NN and 9N~...........................................

14

Excitation of Two-Phonon States through Exchange Current ........................

15

Variational Approach to Collective Excitations ......................................

16

Relativistic and Non-Relativistic Mean Field Investigation of the Superdeformed
Bands in 62Zn ........ . .............................................................

17

SD Pair Approximations of the Nuclear Collective Motion... .. ... .. ..... .. ... .. ... ..

18

The Pseudo-Spin Symmetry in Zr and Sn Isotopes from the Proton DripLine to the Neutron Drip Line . ....... . . ...... . ........................ .............

19

The Pseudo-Spin Symmetry in Relativistic Mean Field Theory ......................

20

The Pseudo-Spin Symmetry in Dirac Equation ......................................

21

Triaxial Deformation of Medium Heavy Nuclei in Relativistic Mean Field Theory
with Pairing Correlation ............................................................

22

SU(3) Symmetry in Oblate and Triaxial Nuclei. ........ .......... .... ... .. ... .. ... ..

23

Relativistic Mean Field Investigation of the Identical Bands and Band Crossingin the Superdeformed Eu-Gd Nuclei .................................................

24

Band Structures of 1820s Studied by GCM Based on 3D-CHFB .....................

25

Width and Shape of the Hot Giant Dipole Resonance ................................

26

Contribution of Higher-Order Processes to the Damping of Hot Giant
Dipole Resonance.... .... .. .. ........ .. .... . ........ .. .... . .... ...... .. .. . ....... ...

27

Damping of Hot Giant Dipole Resonance Due to Complex Configuration Mixing.... .

28

Shape Evolution of the Hot Giant Dipole Resonance29Damping of Double Giant Dipole Resonance ...................... . . . . . . . . . . . . . . . . . . .

30

Reaction Cross-Sections in the Quantum Molecular Dynamical Approach ............

31

Relativistic EOS Table Constrained by Unstable Nuclei for Supernova andr-Process Simulations ..................... ..................... .. ...................

32

The Long Half-Life of Highly Ionized 44Ti ...........................................

33

The Half-Life of 44Ti and SN 1987A .................................................

34

Correlation and Finite Interaction-Range Effects in High Energy Electron
Inclusive Scattering .................................................................

35

Transversity Distributions and Spin Asymmetries at RHIC ............... . ..........

36

A New Parametrization of Polarized Parton Distributions in the Nucleon ............

37

Semi-Classical Sine-Gordon Solitons on a Finite Interval .............................

38

Muon Catalyzed Fusion and Muon to 3He Transfer in Solid T2 Studied by X-Ray
and Neutron Detections.............. ................. ....... ........ ....... ... .....

40

Measurements of 3He Accumulation Effect on Muon Catalyzed Fusionin the Solid/Liquid D-T Mixtures .............. .... .................................

41

Muon to Alpha Sticking K,e/K a X-Ray Ratio in Muon Catalyzed D-T Fusion
at the RIKEN-RAL Muon Facility.............. ....................................

42

X-Ray and Neutron Measurement of a-Sticking Probability in Muon Catalyzed dt
Fusion at the RIKEN-RAL Muon Facility...................................... .. ...

43

RHIC Spin Project ....................................... ... .......................

44

Simulation of the J /'Ij; Production in Polarized Proton-Proton Collision ..... ........ .

45

Measurement of the Proton Polarization at 21.6 GeV /e for AGS E925 ...............

46

Performance of PHENIX EM-Calorimeter for Spin Physics ..........................

47

Construction and Quality Assurance of the Large Muon Identifier Panels
for PHENIX at BNL ................................................................

48

Installation and Quality Test of Muon Identifier in Japan for PHENIX. . . . . . . . . . . . . . .

50

R& D of CNI Polarimeter with Carbon Target ......................................

52

Plan for the PHENIX Computing Center in Japan ..................................

53

A High-spin Isomer in 143Nd ............... ........................... .. .. . .........

54

In-Beam Gamma-Ray Study with HSIB of 145mSm ................ . ...... .. ...... . ..

56

a-Decays of 1959,m At and 199Fr .... ......... ... ......... ........ .....................

57

Experimental Result of the 40 Ar + 238U Fusion Reaction ............................

58

Plan for Lifetime Measurements of Excited States Using the Recoil Decay
Tagging Technique with Gas-Filled Recoil Separator. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

59

Reaction Products from the 208Pb + 208Pb Reaction at 15A MeV ...................

61

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

62

3....

....

4

.

The He(d,p) He ReactIOn at Ed = 140 and 270 MeV ...............................

63

2.

Spectroscopy of 11 Be via 11 B( d , 2He) 11 Be Reaction at Ed = 270 Me V

64

Measurement of Elastic and Inelastic Scattering of Polarized Deuterons from
28Si at 270 Me V ....................................................................

65

Gamow-Teller Strength of 28Si , 32S, and 34S( d, 2He) .................................

66

Transverse Momentum Distribution of Fragments in Reaction 40 Ar + 9Be ............

67

Projectile-like Fragment Momentum Distributions from 40 Ar + natTa Reaction
at 94A MeV........................................................................

68

Measarement of Fusion Cross Section of Neutron-Skin Nucleus 6He ..................

70

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

71

Momentum Distributions of Projectile Fragments for Light Proton Drip-Line Nuclei. .

72

Charge Exchange Reaction of 14Be ..................................................

73

Coulomb Dissociation of 11 Be and 15C ............................................. .

74

Shell Structure Study of the Proton Rich Nucleus 17Ne via the (p, 2p) Reaction. . . . . .

75

Magnetic Moment and Electric Quadrupole MOIll€nt of the 18N Ground State ........

77

The First Measurements of Half Lives and Neutron Emission Probabilities ofVery Neutron Rich Nuclides of Mg, AI, Si, and P ....................................

78

Quadrupole Moment of 39Ca ........................................................

79

Production of 44Ti at the RIKEN RIPS Facility............. .. ............ . .........

80

Development of Polarized 129Xe Solid for Polarization of Unstable Nuclei ............

81

Coulomb Dissociation of 8B at 254A MeV............ . ..... ........ ......... . .......

82

Measurements of Interaction Cross-Sections for Carbon Isotopes at Relativistic
Energies and the Halo Structure in 19C ..............................................

83

Atomic and Solid-State Physics
Charge Transfer Processes in Collisions of H+ Ions with P Atoms at Low Energies

85

A Comparative Study of Electron- and Positron-Polyatomic Molecule Scattering .....

86

Low-Energy Positron Collisions with CH 4 Molecule and Ar Atom.. ... ...............

87

Close Coupling Calculation for e + Ps Scattering. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. .

88

Protonium Formation in p- H Collisions ..............................................

89

Time-of-Flight Mass Spectroscopy of Product Ions in Fast Ion-C60 Collision

90

Sub-State-Selective Differential Cross Sections of Electron Capture in
10 MeV Ar 8+ -He Collisions ............... . .........................................

91

Effects of the Ion Beam Energy on Atomic Lifetime Measurements Using
the Techniques of Beam-Foil Spectroscopy ...........................................

92

Beam Foil Spectroscopy of Highly Charged Erbium... ... .. ........ .. . .... ..... ... ...

93

Continued Studies of the Beam-Foil Technique for Atomic Lifetime Measurements
Using Li-like Ne ....................................................................

94

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

95

3.

Crossed Beam Experiment of Highly Charged Ion-Atom Collision in
the Energy Range below 100 eV /q ..................................................

96

Angular Distribution of Auger Electrons from Doubly-Excited N3+ Produced by
the 50 keV N 5+ -Ar Collisions .......................................................

97

Double Electron Capture vs. Target Excitation in Slow He 2+ + He Collisions

98

Ion-Velocity Effects on Defect Production in an Ion-Irradiated High-Tc
Superconductor. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

99

Vortex Pinning of Splayed Columnar Defects in Bi2Sr2CaCu20y .....................

100

Columnar Defect-Induced Strain and Superconductivity in Bi2Sr2CaCu20x
Observed by LT-STS/STM ..........................................................

102

Magnetic Excitations from the Two-Leg Spin Ladder in L8{)Ca8Cu24041 .............

103

Laser Spectroscopic Study of Metastable Ne Atoms in Gaseous and Liquid He .......

104

Channeling Analysis of ZnSeTe ......................................................

106

Single Event Burnout in Power MOSFET Caused by High-Energy Ions..............

107

Possibility of the "~ Effect" in the Zn-Substituted Bi-2212 System Studied by j.LSR ..

108

Muon Spin Resonance in (Ndl-ySmy)o.5Sro.5Mn03 ..................................

109

Level Crossing Resonance in 2H- NbSe2 ..............................................

110

Muon Spin Resonance in KCuC13 and TICuCl3 ......................................

112

j.L+SR Investigation of the Magnetic Ordering in Ce3Pd2oGe6 ........................

113

Muon Spin RF-Resonance of Haldane Gap Systems... ............. ..................

114

Spin Dynamics of 2D Kagome Antiferromagnet, m-MPYNNBF 4, Studied by j.LSR ...

115

j.LSR Studies on 4-Arylmethyleneamino-TEMPO .....................................

116

Muon Studies on Weak Organic Charge Transfer Compounds........................

118

Development and Test of the RF-/LSR System at RAL

119

Radiochemistry and Nuclear Chemistry

Comparative Regional Uptake Behaviors of a Radioactive Multitracer in Brain of
the Young and Aged C57BL/6N Mice ...............................................

121

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

122

Multitracer Study on the Soil-to-Plant Transfer of Radionuclides in Brassica rapa
L. var. perviridis Bail (Komatsuna) at Different Growth Stages .....................

123

Reduced Uptake of Mn in Cd-Resistant Metallothionein Null Fibroblast .............

124

Influence of Citrate Ions on the Complex Formation of Lanthanide Ions with Bovine
Serum Albumin and Transferrin. ..... ....... .. ... .. ... .. ... ..... .. ... ....... ....... .

125

Behavior of Various Trace Elements in Zinc Deficient Mice ..........................

127

Uptake and Distribution of Trace Elements in Yeast Saccharomyces cerevisiae ......

128

Bioaccumulation and Distribution of Sr, Tc and Cs in Soybean ......................

129

Uptake of Rare Earth Elements by Plants. ... .. ........ .. .. . .. .. .. . ... .. .. .. . .... ...

130

4.

5.

Study on the Uptake of Various Elements into Arbuscular Mycorrhizal Marigold byMultitracer Technique ..............................................................

131

Study on the Distribution of Various Elements in Arbuscular Mycorrhizal Marigold
by Multitracer Technique ...........................................................

132

Formation of Metallofullerenes Studied by the Multitracer Technique ................

133

Application of the Multitracer for Substoichiometric Determination of Trace
Elements: A Proposal ...............................................................

134

Intense 18F Positron Beam Source Electro-deposited on Graphite

135

Radiation Chemistry and Radiation Biology
A New 100 ps-Lived Luminescence in Ion Irradiated Insulator Crystals. . . . . . . . . . . . . . .

137

Ion-Induced Stimulated Emission of 326 nm Band in a-Alumina.. ..... ..... ..... .. ..

138

Luminescence Spectra and Decay Curves of Ion Irradiated CVD Diamond ...........

139

Intramolecular Electron Transfer in Cytochrome c Observed by the Muon Spin
Relaxation Method .................................................................

140

Translocation Behavior of Sr, Rb, and Zn in Soybean... .............................

142

LET Dependence of Survival in Arabidopsis thaliana Irradiated with Accelerated
Heavy Ions .........................................................................

144

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

145

Isolation of the Flower-Color Changing Mutant Using Heavy-Ion Beam Irradiation

146

Produciton of Non-Organogenic and Loosely-Attached Callus in Leaf Disk Cultureof Haploid Nicotiana plumbaginifolia by 14N Ion Beam Irradiation........... ... ...

147

Biological Effects of Heavy-Ion Beam on Budding Yeast Cells. . . . . . . . . . . . . . . .. . . . . . ..

148

Effects of Heavy-Ion Beams on Radio-Sensitive Mutant Cell Lines ...................

149

Potentially Lethal Damage Repair on the Human Skin Fibroblasts Irradiatedwith Ar Ions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . .

150

Judgement on "Hit or Non-Hit" by Time-Lapse Observations of CHO Cells Exposed
to Accelerated Iron-Ions ............................................................

151

Apoptosis Induction and Cell-Cycle Change of Human Cancer Cell-Line Caused by
Heavy-Ions and X-Rays .................................................... . ........

152

Influence of p53-Gene Function on the Specificity in hprt Mutations Induced by
Heavy-Ions .........................................................................

154

Induction of p53 and p21 in Human Cells after Heavy-Ion Irradiations ...............

155

Heavy Ion Beams: An Application to Mouse Mutagenesis.......... .. ..... ........ .. .

156

Instrumentation
Measurement and Simulation of the GARIS Quadrupole Magnet

157

Simulation of the Ion Trajectories in the Gas-filled Recoil Separator .................

158

New Data Acquisition Systems for the Spectrograph SMART.. .......... .. ..... .. ...

159

Improvement of Polarized 3He Target ...............................................

160

Construction of a New Low-Energy Deuteron Polarimeter ...........................

161

6.

IV.

Beam Calibration of Heavy Ion Telescope on Board MIDORI Satellite ...............

162

Calibration Test of Dose Monitor on Board the ADEOS-II ...........................

163

Performance Study of the Plastic Scintillator for BESS Experiment with
Heavy-Ion Beams ...................................................................

165

Construction of a Liquid Hydrogen Target. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

167

High Resolution MUltiple Sampling Ionization Chamber (MUSIC) Sensitive to
Position Coordinates. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

168

Fast-Neutron Measurement Using a Scintillating Fiber Stack with Neutron Beam
From 7Li(p, nrBe Reaction ................................... .. ................... .'169

Position Sensitive Detector Using Scintillation Fiber .................................

170

Measurement of the Energy of Heavy Ions at Around 100 MeV/nucleon with
Allene-Doped Liquid Argon Ionization Chamber .....................................

172

Multiwire Proportional Chamber Read-Out System for Pulsed Muon Facilities

173

Material Analysis
Chemical Shift Measurements of K Ctl,2 Lines Using an In-Air High-Resolution
PIXE System....... ............... ........................... .......... ............

175

Trace-Element Analysis of Feathers Using PIXE177

DEVELOPMENT OF ACCELERATOR FACILITIES

Improvement of Sextupole Magnet for RIKEN 10-GHz ECRIS

179

Off-Centered Compact Duoplasmatron Negative Hydrogen Ion Source with Small
Permanent Magnets...................................... ...........................

180

Advanced Acceleration Concept Taking Place in ECRIS (I) ..........................

182

Advanced Acceleration Concept Taking Place in ECRIS (II) .........................

184

Model Study of a Resonator for Flat-Top Acceleration System in the RIKENAVF Cyclotron.....................................................................

186

Measurement of the Pumping Speed and Pumping Capacity for Photon Detection
System.............................................................................

188

Present Status of RIKEN Microbeam Project ...................................... '.

190

Design of a Charge-State Multiplier System for the RIKEN RI-Beam Factory
Project .............................................................................

191

Status of the Two Booster Ring Cyclotrons for RIKEN RI Beam Factory ............

193

Design Study of the IRC for RIKEN RI-Beam Factory ..............................

195

Orbit Analysis of RIKEN Superconducting Ring Cyclotron ..........................

197

Beam Optics Study on Single-Turn Extraction for RIKEN Superconducting
Ring Cyclotron .....................................................................

199

Design and R&D Works for SRC Sector Magnets...................... ..............

201

Quench Analysis for Magnet Protection of RIKEN Superconducting Ring
Cyclotron ............................ ..................... ............. ........ . .. ..

203

V.

Leakage Magnetic Field from RIKEN Superconducting Ring Cyclotron ..............

205

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

206

Design of the RF Resonators for the New Booster Ring Cyclotrons ..................

208

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

210

Development of ACR Electron Cooler (1) ...........................................

212

Design Study of Electric Power Station for RIKEN-MUSES Project ..................

214

Design of a Slow Extraction System at Booster Synchrotron for MUSES .............

216

Ferrite Test Cavity for MUSES. ... .. . .................. .... ...... ... ..... ...........

218

Simulation of Coherent Behavior of Electron-Cooled Bunched Ion Beamat the Ion-Storage Ring of RIKEN RI-Beam Factory Project ........................

220

Calculation of Single-Bunch Instability of Electron Beam at DSR ....................

222

Design Study of Superconducting Quadrupoles for RIKEN Big RIPS ................

224

Symplectification for the Map of Orbital Motion in a Realistic Siberian Snake
Obtained by DA Approach ..........................................................

226

RADIATION MONITORING

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

229

Dose Rates Due to Residual Radioactivity in the Ring Cyclotron Facility ............

230

VI.

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

233

VII.

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

241

VIII.

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

243

IX.

LIST OF SYMPOSIA

257

X.

LIST OF SEMINARS

258

XI.

LIST OF PERSONNEL

261

AUTHOR INDEX

I. PREFACE

This issue of RIKEN Accelerator Progress Reportcommunicates the research activities of the RIKEN
Accelerator Research Facility (RARF) for the 1998 calendar year. The research programs have been coordinated with the framework of a project entitled Multidisciplinary Research 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 applications, basic studies on energy
production, basic studies on accelerator cancer therapy, material characterization, applications to spacescience, accelerator physics and engineering, laser technology, and computational technology. These activities involve 12 laboratories in RIKEN and more than
400 researchers including outside members from domestic and foreign institutions. Sixty-five universities
and institutes from with in Japan and 36 institutes
from 12 countries are included.
The major research activities of the RARF are basedon the heavy-ion accelerator complex consisting of theK = 540 RIKEN Ring Cyclotron (RRC) , the energyvariable heavy-ion linear accelerator (RILAC) and theK = 70 azimuthally variable field cyclotron (AVF) ,which have altogether provided a beam time (on thetarget) of more than 8000 h throughout the year.
The three accelerators deliver heavy-ion beams ofa variety of elements with energies ranging from a few
A MeV to 135A MeV. The two injector machines (AVF
and RILAC) are equipped with ECR heavy ion sources.
The AVF is additionally equipped with a polarized ion
source for vector and tensor polarized deuterons. Recently, the capabilities of the RILAC have been dramatically enhanced by addition of a new 18 GHz ECRion source followed by a frequency-variable RFQ preaccelerator. Heavy ion intensities have increased fromten to one hundred times that in the original setup.
The three accelerators have been used in various configurations. The RRC operates with the AVF or the
RILAC as the injector. The AVF provides beams ofions of mass number up to 60 and the RILAC provides
beams of ions of large mass number. In addition, theAVF and the RILAC can be used separately, when they
are not used as injectors, for low-energy applications.
Two-thirds of the RRC research beam time ('"'-'5000 h
in total) is allotted to nuclear physics and one-third
to atomic physics, material science, nuclear chemistry,
radiation biology and others. Incontrast, the RILAC
and the AVF beam times were used by fields other than
nuclear physics. The research beam times are 2100 h
for the AVF and 800 h for the RILAC.
The use of radioactive ion (RI) beams is the mainemphasis of the studies at the RRC. Three different
types of radioactive beams, i.e., (1) projectile-fragment(PF) radioactive, (2) spin-polarized radioactive, and(3) high-spin isomer beams, have been developed andused in a broad range of nuclear studies. PF beams aremost widely used by virtue of their versatility and highintensities. The spin-polarized beams are particularly
useful for NMR experiments with radioactive isotopes.
The isomer beam intensity has been significantly improved, and is approaching a realistic application level.
These beams are primarily used for studies in nuclear
physics. Major subjects pursued are (1) exotic nuclear
structure and new dynamics of extremely neutron-richnuclei (such as those with a neutron halo or skin) , (2)nuclear astrophysics involving unstable-nucleus reactions, (3) synthesis of new unstable isotopes far fromthe range of stability, (4) extensive measurements ofnuclear moments, and (5) high-spin physics investigated using isomer beams. The characteristic featuresof intermediate-energy direct reactions are often exploited for such studies.
The RI beams are useful for other domains of science as well. In particular, applications in condensed
matter science have been developed to a large extent
by exploiting the on-line capability of Mossbauer and
PAC spectroscopy techniques which are feasible onlywith RI beams.
Intermediate-energy heavy ions from the RRC havefound their own applications. A strikingly efficientmutagenic effect was observed when the embryo of a
Tobacco plant was bombarded by heavy ions. Highenergy heavy ions irradiated the plants which were
(naturally) placed in air to obtain a desirable amountof Linear Energy Transfer (LET) through the sample. This technique has made available a new schemeof mutant production which is efficient and well controlled. The method is so efficient that it is expected
to offer new possibilities in bioscience research throughcomparison of normal and mutagenized samples. To
obtain more detailed information, such as the crosstalks between cells, the development of a microbeam
is planned.
Another significant development has been seen in theapplication of the radioactive tracer technique. Highenergy heavy ion reactions facilitate the simultaneous
production of a wide variety of isotopes. This feature
is exploited to cultivate a novel multitracer methodology in which a radioactive tracer source containinga variety of elements is prepared for injection into asample. This method enables the study of the circulation behavior of different elements in a common sample, drastically improving the reliability and efficiency
1

over those of single-tracer experiments. The application of the method is rapidly extending to the fields of
bio-inorganic chemistry, dietetics, toxicology, pharmacology, environmental studies, and the medical field ingeneral.
The RARF hosts many international collaborations,among which are two large international collaboration
programs using overseas accelerator facilities: One is
the muon science project at ISIS in collaboration with
the Rutherford-Appleton Laboratory (RAL), and theother is the spin physics program at RHIC in collaboration with the Brookhaven National Laboratory (BNL).
The pulsed muon beam facility at ISIS has enteredinto a stage of steady operation. Great success wasachieved in observing the X-rays generated in J..L capture by alpha particles produced by muon catalyzed fusion. Studies of quark-gluon spin structure functionsat BNL/RHIC are in progress and will be ready forthe commissioning of RHIC operation in 1999. The
RIKEN /BNL Research Center is in operation and attracts physicists from all over the world.
The RI Beam Factory Project was started this year.
The construction of the test sector magnet for the Superconducting Ring Cyclotron (SRC, K = 2500 MeV)
has been started. Design work on the booster cyclotron(ISR) and the other facilities are also in progress.

I. Tanihata
Director
RIKEN Accelerator Research Facility

2

II.

OPERATION OF ACCELERATORSRIKEN Accel. Prog. Rep. 32 (1999)

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 in a
steady operation and has supplied various kinds of ion
beams for various experiments. Table 1 is the statistics of the number of days operated during January
through December, 1998. One day of the scheduled
beam time was forced to be cancelled owing to thefailure in the No. 1 rf amplifier. Table 2 summarizes the number of days allotted to different researchgroups. The percentage of the beam time used by thegroup of RIKEN Ring Cyclotron (RRC) was approximately 46% of the total. The ions of 160, 40 Ar, 58Ni,
84Kr, 128Te, 136Xe, 18 1Ta, 208Pb, and 209Bi accelerated by RILAC were injected to RRC . Tables 3 and 4
are the statistics of the number of days of the RILAC
ion beams delivered using the Cockcroft-Walton injector with an 8-GHz ECR ion source (NEOMAFIOS)

Table 3. Statistics of the RILAC ion beams delivered using
the Cockcroft-Walton injector.
Ion
He

Mass Charge states

4

2

B

11

1,3

C
N

12
15
16
20
24
27
40
166
181
208
209

1,2,4

0
Ne
Mg
AI
Ar
Er
Ta
Pb
Bi

3,4
3

4
5
6
8
18
16
11

16
Total

Days

9
9
7
9
2
3
9

2
6
7
3
4
71

Table 1. Statistics of the RILAC operation during January
1 through December 31, 1998.
Table 4. Statistics of the RILAC ion beams delivered using
the new pre-injector.

Days

%

Beam time

171

46.8

Ion
He

Overhaul and improvement

40

11.0

AI

Periodic inspection and repair

52

14.2
0.3

Machine trouble
Scheduled shut down
Total

101

27.7

365

100

Ar
Fe
Ni
Kr
Kr
Te
Xe

Mass Charge states

Days

1
7
5,8,9,11,12
15
9
18
11,13,19,20
19
18,20,27

1
3
23
4
9
2
5
8
45
100

4
27
40
56
58
78
84
128
136

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

Atomic physics

48

28.1

Nuclear physics

12

7.0

Radiation chemistry

17

9.9

Material analysis and development

4

2.3

Instrumentation3

1.8

Accelerator research

95.3

Beam transport to RRC

78

45 .6

171

100

Total

Sumijyu Accelerator Service, Ltd .

and those delivered using the new pre-injector (consisting of an 18-GHz ECR ion source and a variablefrequency RFQ equipped with a folded-coaxial resonator), respectively. The ion beams of 18 kinds ofelement were used for the experiments and beam acceleration tests. The percentage of the beam time tohave used metallic ions amounted approximately 35%of the total.
We carried out following machine improvements during this reporting period: (1) Aperture of the rebuncher installed after the RFQ has been enlarged
from 40 mm to 50 mm in diameter in order to accept the beam having an emittance larger than the designed value. (2) With NEOMAFIOS, we have tested
a method of production of metallic ions by using materials such as EU203. As a result, we were successful3to obtain the beam intensity of 28 eJ-lA for Eu 1.2+ and
4 eJ-lA for Eu 18+. The ions of 10 kinds of gaseous elements and those of 51 kinds of solid elements havebeen produced by the NEOMAFIOS till today. (3)The beam slits, Faraday cups, and beam profile monitors of the beam transport line A were replaced withnew ones in order to improve their strengths against
the high beam intensity extractable from an 18-GHz
ECR ion source. They were normally mounted on adiagnostic chamber.
We experienced following machine troubles during
this reporting period: (1) In the resonator No.6, a thincopper sheet (of 10 cm wide, 7 cm long, and 0.3 mm

4thick) used for electric contact was melted down due
to the excessive rf current and parasitic oscillation. (2)A potential transformer was worn out in a high voltage power supply (440 kW) for the final vacuum tube
(No.1 and No.2), and we replaced it with a new one.
(3) Power supplies for the screen grid (1.5 kV, 2.2 A) of
the final vacuum tube (No.6), for the filament (4.5 V,
1640 A) of the final vacuum tube (No.1), and for theplate (5 kV, 2 A) of the driving vacuum tube (No.3)
had troubles, and we replaced it with spare ones. (4)Three heat exchangers in a water cooling system wereover hauled because of a deterioration in the thermal
efficiency.

RIKEN Accel. Prog. Rep . 32 (1999)

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,*R. Ichikawa,* N. Tsukiori,* K. Takahashi,* T. Maie,* T. Homma,* K. Kobayashi,* and Y. Yano
During one year of 1998, the RIKEN Ring Cyclotron(RRC) and AVF cyclotron were in a favorable condition as in other years. Many kinds of beams were accelerated with RRC as shown in Fig. 1. Among them,nine kinds of beams were newly accelerated in 1998.
They are listed in Table 1 together with their acceleration data.

0.6

200
•

lons accelerated
from I \/87 to 1997olons accelerated in 1998

1:
co

:.J
....
o

>.

,-,. 150g

0.5 .[1
o

U:;:)

'ii

>

'g

~

..e
Q.)

e 100

A total of operation hours of the year 1998 amounted
6600 hr, and among those, 4840 hr were spent for socalled "beam time" for various experiments. 73% of
the beam time were devoted to the nuclear physics experiments and 27% to the other fields such as: medical
science, radio-chemistry, health physics, material science, biology, and atomic physics.
Figure 2 shows the operation statistics of twelve
years from 1987 to 1998. The fraction of the nuclear
physics experiments had a peak of 4300 hr in 1996, andthen decreased by 15% after that. This is due to thefact that an experiment in search of the super-heavy
element has been stopped since 1997. On the otherhands, the share to non-nuclear physics experiment isincreasing gradually, since the application for biological and biomedical reserach are being expanded. As
the results, a total of beam time have been kept around4700 hr since 1994.

"0
0.4 >

RILAC-RRC

Construction Time

(Hours)

/

9000

~

8OOOf-

0.3

V

HoHdaysor Mainlenance",V

Nuclear Physics

7000 1-

0.2

10

6OOOf-o

He Al Ar Fe
I

I' ' , '

"

Kr

Xe

"

i

i "',

.
I

Er Ta
it'

Bi

I'

100

5OOO f-

200
40001-

Atomic Mass Number
I

3000 f-Fig. 1. The performance of RRC. The beams which wereaccelerated newly during the year 1998 are shown by
open circles and those which have been accelerated since1987 are shown by solid circles.

P

Research

2000
1000

Ivl
1987

1988

fL-

1989

1990 1991 1992 1993 1994 1995 1996 1997 1998
(Year)

Table 1. List of new beams in 1998.
Particle

16
40
40
oI6
58

0

Charge state
IS
RRC
+3

+3

Fig. 2. Statistics of the RRC operation during these twelve
years from 1987 to 1998.

EnergyFrequency(~H z)

Harmonic
No. ( RRC )Injector(~eV/n)Beam Intensity
(pnA)

16

24.6

10

18ECR+RFQ+~C

>2000

Ar

+9

+9

24

27.0

18ECR+RFQt~C

UOO

Ca

+11

+18

100

29.0

IOECR.AVF

33

Ti

+12

+20

90

27.6

10000+AVF

Ni

'19

+9

25

21.S

18ECR+RFQ+~C

58 Ni

12
.

23

+16

+24

90

27.6

+19

+19

8.3

27.6

II

18ECR+RFQ+~C

Xe

+18

+18

7.6

18.8

11

I8ECR+RFQ+~C

5~

20IPb

+11

+30

9.S

19.1

10

? N-ECR~C

1.7

128

I36

Te

10ECR :

10000+AVF

1OGHz ECR Ion Source

18ECR:

18GHz ECR Ion Source

N-ECR :

Neomafios ECR Ion Source

Sumijyu Accelerator Service, Ltd .

A total of the unscheduled shutdown due to machine
troubles was 157 hr in 1998, the minimum in these
12 years. In this year, machine troubles were mainly
related to the low-level circuits of rf system, and any
big troubles relating to the vacuum leak did not occur.
AVF cyclotron was used as the stand-alone for
700 hr in 1998. Kinds of beam were limited to protonand polarized-deuteron. They were used for nuclear
physics, in-beam Mossbauer, and for slow positron
beam production.
In the end of 1997, the official limit for the maximum
beam intensities was raised for low-energy beams at
RRC. According to the new permission, the maximum
beam intensity is inversely proportional to a beam en5

ergy. For example, it has become 10 pJ-LA for beams
with energy of 13.5 MeV/nucleon, while it is still 1 pJ-LA
for 135 MeV/nucleon same as before. In February
1998, a 24 MeV/nucleon 40 Ar beam was accelerated
with the intensity more than 2 pJ-LA and was used fora simulation test of the rotation target prototype for
BigRIPS in RIBF. The input beam power was morethan 2 kW.
A gas target of RIPS for production of a high spinisomer beam became ready to use and was tested several times using a beam of 7.6 Me V / nucleon 136 Xe with
the intensity of 0.5 pJ-LA.
A drift of the magnetic fields in RRC sector magnets
has been frequently problem. In search of causes of thedrift, two kinds of devices were newly installed in thesummer 1998. A dc current transformer (DCCT) was
added to monitor an output of the main coil power supply. A precise measurement of dc current has become
possible independent of a feedback loop in the power
supply. And also NMR probes were installed in every
sector magnet at the radius of around 3500 mm. In
the S- and W-sectors, the probe position is fixed andin the N- and E-sectors the probes can be removed
remotely because they intercept the orbits of an extracted beam. Using also data of temperatures aroundthe sector magnets, the monitoring of the magnetic
field has now completed.
A sextupole magnet in 10 GHz ECR ion source wasconverted into a new type of N38H permanent magnets in the summer 1998. The maximum field strength

6of the new one is about l.6 times that of the old.
Since the confining magnetic field was strengthened,
the beam intensity as well as the stability of plasma
has been improved. A new ECR ion source using a
super-conducting solenoid are being fabricated in factories, and will be completed in the summer of 1999.
In order to prepare the space for RIBF, most of thebuilding on the east side of Nishina Memorial Building
will be removed in the spring of 1999. In advance to it ,the power substation for the all existing machines is going to be moved to the west side of the Nishina Memorial Building. Moreover, the houses for RF power supply for both RRC and RILAC will be changed to newones on this side. For two months from February to
April 1999, the whole machine will be shutdown due
to these changes of power line.
During the shutdown period, improvement of injection system of RRC is scheduled. Two sets of Magnetic
Inflection Channels (MICI & MIC2) will be replacedwith new ones and the size of beam pipe will be enlarged slightly. Beam monitors along the injection line
will be replaced with new types preparing for the highintense beam injection in the future.
Design of cavity for Charge State Multiplier (CSM)
is now in progress. In the summer of 1999, the first unitof CSM consisting of three cavities (two acceleratorsand one decelerator) will be installed in the second
target room of RILAC, along the injection beam line
to RRC.

RIKEN Accel. Prog. Rep. 32 (1999)

The Tandem Operation
K. Ogiwara, E. Yagi, and T. Urai
The 1.7 MV tandem accelerator was operated for
95 days, except for the machine inspection, beam test,
and so on, during the annual reporting period from
Nov. 1, 1997 to Oct. 31, 1998.
Experimental studies on the following subjects havebeen performed, and some of them are in progress:(1) Rutherford Backscattering Spectroscopy (RBS)(a) Behavior of the Xe atoms implanted into iron.
(b) Channeling analysis of dopants in II-VI compound semiconductors.
(c) RBS study of multilayer films , welded steel, andoxides.
(d) RBS analysis of the polystyrene surfaces andglassy carbon films modified by means of ion implantation.

(2) Nuclear Reaction Analysis (NRA)(a) Study on the lattice location of hydrogen in niobium alloys by a channeling method.
(3) Particle-Induced X-ray Emission (PIXE)(a) Application of PIXE to the biomedical and material sciences: Trace element analysis using energydispersive X-ray spectrometry, and chemical state
analysis using wave-dispersive X-ray spectrometry.
(b) Trace element analysis of feathers for monitoring
the environmental pollusion.
(c) Development of an in-air high-resolution PIXE
system for chemical state analysis.
(d) Characterization of II-VI ternary semiconducting crystals.

7

III.

RESEARCH ACTIVITIES1. Nuclear Physics

RIKEN Accel. Prog. Rep. 32 (1999)

Structure of N
20 Unstable Nuclei Studied
by Monte Carlo Shell Modelf'V

Y. Utsuno, T. Otsuka, T. Mizusaki, and M. Honma[Monte Carlo shell model, Shell closure]
The neutron-rich N
20 region is referred to as
the "island of inversion", where the N = 20 closed
shell structure vanishes. For instance, the N = 20
nucleus 32Mg has been proven to be well deformed
as confirmed by a observed B(E2; ot -+ 2t) value. 1)
We study the structure of nuclei around the "island"
within the framework of the large-scale shell-model calculation by the Quantum Monte Carlo Diagonalization(QMCD) method. 2,3)
The model space is the same as the one in Ref. 3. We
have already confirmed the feasibility of the QMCD
method in this model space and shown that the spurious center-of-mass motion can be removed. 3) We thenrefine the effective interaction, paying attention to themonopole terms and the paring interaction. We havefound that the interplay between the T = 0 and T = 1
monopole interactions plays an important role in thebinding energy and the deformation especially for theoxygen and the neon isotopes. The heaviest bound of
the oxygen isotopes is 240, which is reproduced by themodified interaction.
In order to see competition between the normal andthe intruder configurations intuitively, we calculate
the potential energy sueface (PES) within the shellmodel space. The PES is calculated by the constrained
Hartree-Fock method 4 ) with the constraints of <Jx >= y'I(I + 1), <Qo> = q, and <Q±I> = <Q±2> = O.
Figure 1 shows the PES of 32Mg. We see several local minima in Fig. 1, which suggest the shape coexistence. The lowest-energy state corresponds to the
2p2h excited state from the N = 20 core. We utilize
these minima as starting points of the sampling in the
QMCD method.
Figure 2 shows yrast energy levels of the magnesium
isotopes compared with the experiment. The excitation energies by the QMCD method are in agreementwith experimental ones, while the sd-shell model does
not reproduce the E x (2t) of 32Mg. We predict large
deformation structure for the N = 22 and 24 nuclei.
For these nuclei, the particle-hole excitation from theN = 20 core is still important.
f"V

-128

-130

-132

o

-100

100

q (fm2)

Fig. 1. Potential energy surface of 32Mg. The solid,
dashed, and dotted lines denote I = 0,2,4, respectively.

16

18

20

22

24

N

Fig. 2. Yrast energy levels of the magnesium isotopes. The
circles correspond to the experiment. The closed (open)
symbols are the QMCD calculation (sd-shell model).

References
1) T. Motobayashi et a1.: Phys. Lett. B 346, 9 (1995).

2) T. Otsuka, M. Honma, and T. Mizusaki: Phys. Rev.
Lett. 81, 1588 (1998) and references therein.
3) Y. Utsuno et al.: RIKEN Acce1. Prog. Rep. 31, 15(1998).
4) For instance, P. Ring and P. Schuck: in The Nuclear
Many-Body Problem (Springer, New York, 1980).

9

RIKEN Accel. Prog. Rep. 32 (1999)

Monte Carlo Shell Model Calculation and Computers
N. Shimizu, T. Otsuka, Y. Watanabe, A. Taketani,
T. Mizusaki, and S. Haruyama[Shell model, Nuclear structure, Computational physics]
The nuclear shell model is the most useful approachin describing the various nuclear properties: energy
levels, quadrupole moments, electromagnetic transition probabilities, and so on. In this model, Hamiltonian matrix in the full valence-nucleon Hilbert space
has to be diagonalized. It requires, in many cases,
enormous time even with the latest computers, becauseof huge dimension. For example, the matrix Hamiltonian for 154Sm with the 132Sn closed core has a 4 x 10 13-----~- ------~
~

~
,
.J

,
"

J = 0 basis dimension.
In order to overcome this difficulty, the Monte
Carlo approach incorporating both the diagonalization method and the auxiliary field technique has beendeveloped. 1-4) Because this approach handles a small
number of bases, it does not only decrease time tocalculate, but also makes parallel computation easierdrastically.
In Oct. 1998, we introduced the computer system
which consists of 34 Alpha CPUs in order to perform the above-mentioned large-scale calculations. As
well, this system is a prototype of larger system named"High Performance Personal Computer System" to beinstalled in March, 1999.
The framework of the prototype system is illustrated
in Fig. 1 and several features are listed as follows:• 8 Alpha CPUs (Red Hat Linux) at 533 MHz and

24 Alpha CPUs (Red Hat Linux) at 600 MHz serveas slave computers. They have no magnetic disks
and perform only parallel calculations.

• One Alpha CPU (Digital UNIX) at 667 MHz is
the front-end computer and is able to integrate
32 slave computers. The front-end computer always monitors their individual state (power supply and temperature) under watch respectively
with controller (referred as PSjT cont. in Fig. 1).

10

Fig. 1. Framework of computer system introduced in Oct.
1998.

• One Alpha CPU (Red Hat Linux) at 533 MHz is
prepared for the slave computers to boot throughthe network by using the Network File System.
• They are connected with each other by 100 Mbps
Ethernet. Although it is slower than many otherrecent parallel-computing systems , this is sufficient for the present Monte Carlo calculations.
References
1) M. Honma, T. Mizusaki, and T. Otsuka: Phys. Rev.
Lett. 75, 1284 (1995).
2) T. Mizusaki, M. Honma, and T. Otsuka: Phys. Rev. C
53, 2786 (1996) .
3) M. Honma, T . Mizusaki, and T. Otsuka: Phys. Rev .
Lett . 77, 3315 (1996).
4) T. Otsuka, M. Honma, and T . Mizusaki: Phys. Rev.
Lett. 81 , 1588 (1998).

RIKEN Accel. Prog. Rep. 32 (1999)

Relativistic Continuum Hartree-Bogoliubov Theory with Both Zero
Range and Finite Range Gogny Force and Their Application t
J. Meng[Relativistic continuum Hartree-Bogoliubov, Pairing correlation, Drip-line nuclei]
The Relativistic Mean Field (RMF) theory has received wide attention as a successful description formany nuclear phenomena during the past years. The
RMF has been used to describe binding energies, nuclear radii, nuclear density distribution, single particle
spectra, magnetic moments, collective excited states,
the dipole sum rule, shell effects in finite and exotic
nuclei; scattering processes of nucleons on nuclei atintermediate energies; collective excitations such as giant resonances and identical bands in rotating superdeformed nuclei, etc. Obviously, the RMF is one of thebest candidates for application to exotic nuclei. In all
the RMF studies mentioned above, however, the pairing correlation has been neglected or simply treated by
BCS approximation. In order to describe open shell
nuclei, the pairing correlation must be taken into account properly. This is particularly noteworthy since
describing the coupling to the continuum for exotic nuclei, which is very crucial for the description of drip line
nuclei, can only be done in the coordinate representation. This is because the expansion in a localized harmonic oscillator basis provides a poor approximation
to the continuum, even when a large number of oscillator shells are taken into account. For stable nuclei,
the BCS approximation is simple and practical. But
for exotic nuclei it will lead to a partial occupation ofunphysical states in the continuum and therefore to agas of evaporating neutrons.
Recently a fully self-consistent Relativistic Continuum Hartree-Bogoliubov (RCHB) theory, i.e.,
RHB theory in coordinate representation, has been
proposed. 1) It is relativistic in that it is able to take
into account the proper isospin dependence of the spinorbit term, which is crucial for a accurate reproductionof recent measurements of the isotopic shifts in the Pbregion and for a reliable description of nuclei far awayfrom the line of jJ-stability. In addition this theory
provides a self-consistent treatment of pairing correlations in the presence of the continuum. As has beenshown in Ref. 1, the scattering of Cooper pairs into thecontinuum containing low-lying resonances of small orbital angular momentum plays an important role forthe formation of a neutron halo. The dependence ofthe results on the box size was discussed in Ref. 2, in
which the formation of giant halos is discussed for the
first time.

Here we report on the RCHB theory and provide
details of the relevant numerical techniques. We haveundertaken a systematic study of the pairing correlation in the RCHB theory by considering the densitydependent 8-force and finite range Gogny force. The
techniques for the coupled differential equations andcoupled integro-differential equations are also included.
A preliminary application of the solution for the halo in
11 Li has been reported in Ref. 3. After taking into account the pairing and blocking effect, the ground state
properties of Na nuclei has been well reproduced, including the binding energies and rms radii, and thedevelopment of the halo and shell structure has been
discussed. 4 )The formalism for Relativistic Continuum HartreeBogolyubov (RCHB) theory, which is the extension of
the Relativistic Mean Field (RMF) and the Bogoliubov transformation in the coordinate representation
is presented. As the formalism allows for the proper
description of the coupling between the bound state
and the continuum by the pairing force, it is suitable
not only for stable nuclei but also the nuclei near the
drip line. The pairing correlations are taken into account by both a density-dependent force of zero range
and the finite range Gogny force. The development of
the formalism and the numerical techniques involved
are discussed in detail. The physics from the RCHB
and its understanding in the canonical basis are presented. The RCHB theory is used to describe the chainof nickel isotopes extending from the proton drip line
to the neutron drip line. The comparisons of the twoneutron separation energies S2n as well as the neutron,
proton and matter rms radii yield excellent agreement
between the calculations with both interactions andthe experimental values where they exist. Predictions
have also been made for the drip-line nucleus IooNi.
The pairing energies and single particle levels in the
canonical bases and their corresponding occupation
probabilities turn out to be similar.
References
1) J. Meng and P. Ring: Phys. Rev. Lett. 77,3963 (1996).
2) J. Meng and P. Ring: Phys. Rev. Lett. 80,460 (1998).
3) J. Meng et al: Z. Phys. A 358, 123 (1997).
4) J. Meng et al: Phys. Lett . B 419, 1 (1998).

Condensed from the article in Nuel. Phys. A 635, 3 (1998).

11

RIKEN Accel. Prog. Rep. 32 (1999)

The Proton and Neutron Distributions in Na Isotopes:
The Development of Halo and Shell Structure t
J. Meng, I. Tanihata, and S. Yamaji[Relativistic continuum Hartree-Bogoliubov, Neutron halo, Shell structure]
With the exotic matter distribution near the drip
line, many questions are still open; e.g., the relation between the halo and the shell effect, the difference about
the proton and neutron distributions on the stabilityline and away from the stability line. How is the halo
formed? Are there a rapid change from the normal nuclear density to the halo density or a gradual change inthe particle number? Because the matter distribution
is not measurable directly, a series of experiments at
different incident beam energy is necessary in order todetermine the density distribution of both proton andneutron model-independently. Among all the experiments carried out so far, N a isotopes provide a good
opportunity to study the density distributions over awide range of neutron numbers. I) We report in this article a systematic study of the nuclear density distributions in N a isotopes within the Relativistic Mean Field(RMF) theory, properly describing the pairing andthe blocking effect of odd particle system by HartreeBogoliubov theory in coordinate representation, andtry to answer some of the general questions in theselow-density nuclear matter.
People have applied so far rather different techniques
to describe halo phenomena in light nuclei. As for instance: the exact solution of few-body equations treating inert sub-clusters as point particles; the density dependent Hartree-Fock method in a localized mean fieldtaking into account all the particles in a microscopic
way; or a full shell model diagonalizations based on theoscillator spaces with two different oscillator parameters for the core- and halo-particles. Recently, however,a fully self-consistent calculation within the Relativistic continuum Hartree-Bogoliubov (RCHB) theory forthe description of the chain of lithium isotopes ranging
from 6Li to llLi was reported. 2) Here the matter distributions from the proton drip line to the neutron drip
line in Na isotopes have been systematically studied
and presented. The relation between the shell effects
and the halos has been examined. Tail of the matter
distribution shows a strong dependence on the shellstructure.
Summarizing our investigations, the development ofa proton skin as well as neutron skin has been systematically studied with a microscopic RHB model, where
the pairing and blocking effect have been treated selfconsistently. A systematic set of calculations for theCondensed from the article in Phys. Lett. B 419, 1 (1998).

12

ground state properties of nuclei in N a isotopes is presented using the RHB theory together with standard
Glauber theory. The RHB equations are solved selfconsistently in coordinate space so that the continuum
and the pairing have been better treated. 3 ) The calculated binding energies are in good agreement with theexperimental values. A Glauber model calculation has
been carried out with the density obtained from RHB.
A good agreement has been obtained with the measured cross sections for I2C as a target, and a rapid
increase of the cross sections has been predicted forneutron rich N a isotopes beyond 32N a. Systematicsof the proton and neutron distributions are presented.
After a systematic examination of the neutron, proton, and matter distributions in the N a nuclei fromthe proton drip-line to the neutron drip-line, the connection between the tail part of the density and theshell structure has been found. The tail of the matter
distribution is not so sensitive to how many particles
are filled in a major shell. Instead, it is quite sensitive to whether this shell has occupation or not. The
physics behind the skin and halo has been revealed asa spatial demonstration of shell effect: simply the extra neutrons are filled in the next shell and sub-shell.
This is in agreement with the mechanism observed so
far in the halo system but more general. As the 117/2
is very close to the continuum, the N = 28 closed
shell for stable nuclei fails to appear due to the coming
down of the 2P3/2 and 2PIj2 levels. Another important
conclusion here is that, contrary to the usual impression, the proton density distribution is less sensitive tothe proton to neutron ratio. Instead, it is almost unchanged from the proton drip-line to the neutron dripline . Similar conclusion has been obtained recently bycharge exchange reaction experimently.4) Influence ofthe deformation, which is neglected in the present investigation, is also interesting to us; more extensive
study to extend the present study for deformed cases
are in progress.
References
1) T. Suzuki et al.: Phys. Rev. Lett. 75, 3241 (1995).
2) J. Meng and P. Ring: Phys. Rev. Lett. 77, 3963 (1996) .
J. Meng: Nucl. Phys. A 635, 3 (1998).
3) J. Meng and P. Ring: Phys. Rev. Lett. 80,460 (1998).
4) O. Bochkarev et al.: submitted to Z. Phys.

RIKEN Accel. Prog. Rep. 32 (1999)

A Giant Halo at the Neutron Drip Line t
J. Meng and P. Ring*[Relativistic continuum Hartree-Bogoliubov, Giant halos, Zr-isotopes]
With perpetual improvement in the techniques of
producing radioactive beams , the study of exotic nuclei very-far away from the line of ,B-stability has now
become feasible. Experiments of this kind may cast a
new light on nuclear structure, and novel and entirely
unexpected features may appear: Neutron rich nuclei
can have a structure very different from that of normal nuclei. They consist of a normal core surrounded
by a skin of neutron matter. Close to the drip line,
where the coupling to the continuum becomes important, a neutron halo can develop, as it has been observed in several light nuclei. However, in all of thehalos observed so far, only one has a small number ofneutrons: namely, one or two are outside of the normal core. Even in the chain of He-isotopes, only 6Heshows indications of a possible halo containing 2 neutrons, whereas 8He with its large 2-neutron separationenergy of 2.24 MeV has only a neutron skin.
In order to study the influence of correlations andmany-body effects it would be very interesting to findalso the nuclei with a larger number of neutron distributed in the halo. Here, the Relativistic continuum
Hartree-Bogoliubov (RCHB) theory l) has been used
for the present investigation. It is a relativistic extension of conventional Hartree-Fock-Bogoliubov theory
in coordinate space. Being relativistic , it is able totake into account at the same time the proper isospin
dependence of the spin-orbit term, which is very crucial for an accurate reproduction of recent measurements of the isotopic shifts in the Pb region and fora reliable description of the nuclei far away from theline of ,B-stability. In addition, this theory provides aself-consistent treatment of pairing correlations in thepresence of the continuum. As it has been shown in
Ref. 1, the scattering of Cooper pairs into the continuum containing low-lying resonances of small angularmomentum plays an important role for the formationof a neutron halo. By using a density-dependent zerorange interaction, the halo in 11 Li has been successfully
reproduced in this self-consistent picture. To obtainthese results, a full solution of the RCHB equations
is necessary. The expansion in a harmonic oscillator
basis, which is quite useful only for the nuclei close to
the line of ,8-stability, provides only a very poor approximation in the continuum, even if a large numberof oscillator shells is taken into account. The simple"BCS" -approximation leads to a partial occupation ofunbound states in the continuum, and therefore leads
to a gas of evaporating neutrons. Here, we report on
calculations where the same method as in Ref. 1 has
been used to investigate the halos in Zr nuclei at theneutron drip line.
Because this theory takes into account the proper
isospin dependence of the spin-orbit term, it is able
to provide a good description of global experimental
data not only for stable nuclei but also for exotic nuclei throughout the nuclear chart. 2) In this report we
describe on the theoretical prediction of a giant neutron halo for the Zr isotopes close to the neutron drip
line. Up to six neutrons are formed outside of the 122Zr
core with the magic neutron number N = 82.
Summarizing our investigations, we predict neutron
halos in the Zr nuclei close to the neutron drip line,
which are composed not only by one or two neutrons,
as is the case in the halos investigated so far in light
p-shell nuclei, but which contain up to 6 neutrons.
This is a new phenomenon, which has not been observed experimentally so till today. It would allow the
study of collective phenomena in neutron matter oflow density. This prediction is based on relativistic
Hartree-Bogoliubov theory in the continuum. It combines the advantages of a proper description of the spin
orbit term with those of full Hartree-Bogoliubov theory for the continuum, which allows in the canonicalbasis the scattering of Cooper pairs into low-lying resonances for the continuum. A density-dependent forceof zero range has been used in the pairing channel.
It contains no free parameter, because its strength isadjusted for the isotope 116Zr to a similar calculation
with Gogny's force DIS in the pairing channel. The
halos are formed by two to six neutrons scattered as
Cooper-pairs mainly to the levels 3P3/2, 217/2, 3Pl/2,
and 215/2' This is made possible by the fact that theseresonances in the continuum come down very close to
the Fermi level in these nuclei and is made possible bytheir coupling with the loosely bound levels just below
the continuum limit.

References
1) J. Meng and P. Ring: Phys. Rev. Lett. 77, 3963 (1996) .
2) J. Meng: Nucl. Phys. A 635, 3 (1998) .

Condensed from the article in Phys. Rev. Lett. 80, 460(1998)
Technische Universitat Miinchen, Germany

13

RIKEN Accel. Prog. Rep. 32 (1999)

Landau-Migdal Parameters, g~N and g~L).
T. Suzuki and H. Sakai[Gamow-Teller giant resonances, Landau-Migdal parameters]
The Landau-Migdal parameters for nucleon-nucleon
andspindependent structure of nuclei. They dominate nuclear spin response functions for hadron and electron
scattering!) and the pion-condensation in high-density
nuclear matter. 2 ) Experimentally, however, those values are not known yet. Because of this fact, the socalled universality ansatz, 2,3) g~N = g~ ~ = g~~, hasbeen widely used.
We therefore try to estimate the values of g~N andg~~ from recent experimental data on the excitationenergy and strength of the Gamow-Teller (GT) state. 4)
For this purpose, we use the quark model 5 ) where theinteraction is assumed to be(g~N) '
together with the nucleon-L).(g~L).)
L).-L).(g~~) couplings, play a crucial role inwith (3 = 0.280.
Experimentally, the value of Q has been observed tobe 0.90 ± 0.05 for 90Nb,4) which yields
g~,6. = 0.18 + 0.05g~6.'

where the uncertainty in Q is not considered. Then, if
the value of g~,6. is assumed to be < 1.0,3) we obtain

0.18 < g~~ < 0.23.

·

2 3

where (f7,.jm-rr) = 392 MeV· fm. The spin andisospin operators are given by the sum over the threequarks inside the baryons as usual,(8)

On the other hand , the excitation energy of the GT
states provides us withAKru

= g~N (~:) 2 Po1
1 + {3g~,6. {I - (g~~)2 /(g~~g~N)}

(1)
with

(7)

1 + (3g~~(9)Here, AK:TCT is the strength of the spin-isospin interaction in the nucleon space, which has been already estimated to be 19.8 MeV from the excitation energy,6)and 'Y and Po denote the attenuation factor of the nuclear surface effects and the nuclear mat ter density,
respectively.6) Inserting Eq. (8) into Eq. (9) , we obtain:

0.591 < g~N < 0.594.

(10)

3

(aT)q =

L a(i)r(i).

(3)

i=l

The relationship between the above and LandauMigdal parameters is given by

g~N = G)' VNN , g~" = (D VN",
2g'c,,, =

G)'

V"".

(4)

Using the above interactions, we solve the equationof the random phase approximation in the space of theparticle-hole and L).-hole states, which yields the GT
strength:

I(GTI Lr_a_IO)/2 = Q

L /(p/r_a_/h)/2,

References

(5)

ph

where Q stands for the quenching factor and is given
by

(6)

14

Equations (8) and (10) clearly show that the universality ansatz does not hold.
In conclusion, we have estimated the values of the
Landau-Migdal parameters, g~N and g~,6. ' from recent experimental data on the excitation energy andstrength of the GT state. 4) They are about 0.6 and
0.2, if g~~ < 1, respectively. The value of g~~ is notknown, but the GT strength depends weakly on it . As
a result, the GT strength yields a strong constraint on
the value of g~,6.' Moreover, because of the small valueof g~~ , the excitation energy of the GT state is dominated by g~N" The universality ansatz cannot explain
the strength and excitation energy simultaneously.

1) K. Nishida and M. Ichimura: Phys. Rev. C 51 , 269(1995).
2) J. Meyer-ter-Vehn: Phys. Rep. 14 , 323 (1981) .
3) E. Oset and M. Rho : Phys. Rev . Lett. 42 , 47 (1979).
4) T. Wakasa et al.: Phys. Rev . C 55, 2909 (1997) .
5) T. Suzuki and M . Kohno: Prog. Theor. Phys. 68 , 690(1982).
6) T. Suzuki: Nuel. Phys . A 319 , 110 (1982); T. Suzuki:
Ann. Phys. Fr. (Paris) 9, 535 (1984).

RIKEN Accel. Prog. Rep . 32 (1999)

Excitation of Two-Phonon States throughExchange Current
T. Suzuki[Double giant resonances, Exchange current]
We have investigated photo-excitation of the twophonon states through exchange current. The photoabsorption cross section for dipole states is given innatural units by!)where k denotes the photon energy and j N the isovector nuclear current,(2)
If the nuclear interactions contain the isospin-isospin
interaction:
(3)

i,j

V·J· ex =-~~V(r. r .)
4i L..."t, Ji,j
x{8(r - ri) - 8(r - rj)}{T_iT+j - T+iT-j}.
(4)

We estimate the cross section for the two-phononstates by assuming the Bohr-Mottelson force,2,3)
A

V = ~xLLriYI~(ri)ri· LrjYI/-L(rj)rj,
2
.
.
/-L t
J

(5)

where the strength, X, of the interaction is determinedso as to reproduce the excitation energy, 2w, of the
giant dipole states,
mw 2

41

(9)

we obtain from the sum of Eqs. (7) and (8),O"ex =

5A

2.74

0"0 ~ A2/30"o,(10)where 0"0 denotes the cross section for the giant dipole
state to exhaust the value of the classical energyweighted sum rule and is given by

the exchange current is given by

X = 47r

Wo ~ W2 = 3w, WI = 2w, (r2) = ~(1.2AI/3)2,

16mw(r 2 )1 A· ·r·J'- - ~V(r t,· r·)r
V -2L..."Jt

A

where wo, WI and W2 stand for the excitation energiesof the one-phonon states with 0+,1- and 2+, respectively, and the one-phonon states are assumed to exhaust the values of the classical energy-weighted sum
rule. When we use the experimental values,4)A , (w = AI/3 MeV).

(6)This interaction yields the exchange current which
can excite two-phonon states with [0+ x 1-]I-(T =1, Tz = 0) and [2+ x 1-]1- (T = 1, Tz = 0), where
the one-phonon states with 0+, 1- and 2+ have theisospin quantum number, T = 1 and Tz = ± 1. The
cross sections for these states are calculated to be

0"0 = 7r

2 2

A

e 2m.

(11)

For an example, Eq. (10) gives the cross section for thetwo-phonon state to be about 23% of O"D in 4DCa.
Recently, the double giant dipole and quadrupole
states have been observed through relativistic heavy
ion reactions and through double charge-exchange
reactions. 5 ) Since their isospin is T = 0 or T = 2,
the exchange current cannot excite them, owing to theisospin selection rule. It is very interesting to excite
the two giant resonance states with T = 1 through theexchange current.
References
1) T. de Forest and J. D. Walecka: Adv. Phys. 15, 1(1966).
2) A. Bohr and B. R. Mottelson: Nuclear Structure, Vol.
II (Benjamin, Massachusetts, 1975).
3) T. Suzuki: Nucl. Phys. A 289, 461 (1977).
4) F. E. Bertrand: Ann. Rev. Nucl. Sci. 26, 457 (1976).
5) Ph. Chomaz and N. Frascaria: Phys. Rep. 252, 275(1995).

15

RIKEN Accel. Prog. Rep . 32 (1999)

Variational Approach to Collective Excitations
M. Sambataro* and N. Dinh Dang
[Variational approach, Random-phase approximation, BCS]
In this work we have examined a variational
approach to collective excitations within a boson
formalism. 1 ) Aiming at providing a simultaneous treatment of particle-hole and particle-particle(hole-hole)correlations, we have first introduced quasi-particles.
Bosons have been defined in correspondence with pairsof these quasi-particles. By means of a mapping procedure of Marumori-type we have constructed boson
images of fermion operators truncating the expansionof the boson operators at four-boson terms. RPA-type
phonons have been introduced as Bogolyubov transformations of the above bosons and we have also defined
the ground state of the system as the vacuum of thesephonons. The minimization of the expectation valueof the boson Hamiltonian in this vacuum with respect
to the variables defining the quasi-particles and thephonons operators has allowed to fix these variables.
Important features of this boson procedure are that
(1) no RPA-type inconsistency occurs, (2) no explicit knowledge of the ground state wave function is

National Institute of Nuclear Physics, Catania Section, Italy

16

required and (3) no ambiguities related to the noncommutativity of the phonon operators exist. Also
the variational aspect of the procedure is an importantfeature always allowing to identify the exact groundstate energy as a lower bound of the calculation.
As a test for our approach we have chosen an exactly solvable two-level model characterized by a pairing Hamiltonian. Ground state energies have beenfound in a quite good agreement with the exact results, always remaining located between these and the
BCS ones. We have also calculated the energy of thefirst 0+ excited state and compared it with the BCS
and QRPA values. Also in this case our approach hasoffered a quite good agreement with the exact results
providing globally the best results.
References
1) M. Sambataro and F. Catara: Phys. Rev. C 51, 3066(1995); M. Sambataro and J. Suhonen: Phys. Rev. C
56, 782 (1997).

RIKEN Accel. Prog. Rep. 32 (1999)

Relativistic and Non-Relativistic Mean Field Investigationof the Superdeformed Bands in 62Zn
H. Madokoro and M. Matsuzaki[Relativistic mean field, Superdeformed band, 62Zn]
We study the superdeformed(SD) bands in 62Zn,
which were recently discovered, using a Relativistic
Mean Field (RMF) model. This model starts fromthe Lagrangian which contains nucleonic and mesonicdegrees of freedom. We can extend this model to therotating frame by combining it with the cranking assumption. For detail, see Refs. 1 and 2.
In this study, the occupation numbers of protons ineach parity-signature block (7r = ±, T = ±i) are fixed
to 7r[8 + +; 8 + -; 7 - +; 7 - -]. As for the neutron
occupations, we consider followings,
A: v[8 + +i 8 + -i 8 - +i 8 - -]( 7rtot = +, Ttot = +1),
Dl: v[8 + +i 9 + - i 8 - +i 7 - -](7rtot = -, Ttot = +1),
D2: v[8 + +i 9 + -i 7 - +i 8 - -](7rtot = -, Ttot = -1),
D3: v[9 + +i 8 + -i 8 - +; 7 - -]( 7rtot = -, Ttot = -1),
D4: v[9 + +i 8 + -i 7 - +i 8 - -](7rtot = -, Ttot = +1),
C: v[9 + +i 9 + -i 7 - +i 7 - -]( 7r tot = +, Ttot = +1),
where the total parities and signatures were also
shown. As for the parameter sets, we adopt the ones
called NL1 , NL3, NL-SH, and TMl. Figure 1 shows
the calculated and experimental moments of inertia of
the several SD bands in 62 Zn. Calculation used the set
NLl. Several discontinuities are caused by the crossing between the [303 7/2] and [310 1/2] orbits. Apartfrom these crossings, the bands D3, D4, and C reproduce the experimental data fairly well. From the analysis of the effective alignments, the band C seems tobe the best candidate for the experimentally observed
one. However, we can not exclude the possibility of theband D4 because this band also gives good results if we
adopt the set TMl. As these two bands have different

25

...

~

20

NL1

""',

~.­

t~b~~~dD1 '"::::~~~::
5

D-band D2
D-band D3
D-band D4
SD-band C

62

Znparities, we can determine which one corresponds tothe experimentally observed one if the parity-signatureassignments are performed experimentally.
For comparison, we have also performed theSkyrme Hartree Fock(SHF) calculations using thecode HFODD. 3 ) The parameter sets adopted are SIll,
SkM*, SkP, and SLy4. Figure 2 shows the moments ofinertia of the same SD bands as those of RMF calculations. Calculation here used the set SLy4. Here wefound good agreements for the bands D1, D3, and C.
The analysis of the effective alignments tells us thatthe band C corresponds to the experimental data.
25

SLy4
20

"7; 154)SD-band A --SD-band Dl
SD-bandD2'-'..-,
SD-bandD3
5 D-band D4
SD-band C
exp ....-.
~

M'-' 10o

0.4 0.6 0.8

1

62

Zn

1.2 1.4 1.6

1.8.Q(MeV)

Fig. 2. The moments of inertia calculated by using theset SLy4. The experimental data are shown by black
circles.

We find that these SD bands which reproduce theexperimental moments of inertia fairly well are locatedmore than 1 Me V higher than the lowest SD band inboth RMF and SHF calculations. This may be connected with the unexpectedly high position of the g9/2
single neutron orbit. It seems that all the parameter
sets examined in this work have this feature, which isunresolved yet. In future, we will examine the effects
which are not taken into account in the present investigations. They are, for example, the pairing interactions, which may solve the problem discussed above.
References

0.4 0.6 0.81

1.2 1.4 1.6

1.8

Q(MeV)

Fig. 1. The moments of inertia calculated by using theset NL1. The experimental data are shown by black
circles.

1) W. Koepf and P. Ring: Nucl. Phys. A 493, 61 (1989).
2) H. Madokoro and M. Matsuzaki: Phys. Rev. C 52,
R2934 (1997).
3) J. Dobaczewski and J. Dudek: Comput. Phys. Commun. 102, 183 (1997).

17

RIKEN Accel. Prog. Rep. 32 (1999)

SD Pair Approximations of the Nuclear Collective Motion
Y. M. Zhao, S. Yamaji, N. Yoshinaga, and A. Arima[SD pair approximation, Excitations of medium-heavy nuclei]
Through the success of the IBM 1) and the FDSM,2)
it was recognized that the S D pairs play a dominantrole in the collective motions. In the IBM, S D pairs areapproximated as sd bosons. In the FDSM, SD pairs
are the SP(6) or SO(8) symmetry-dictated SD pairs.
Recently, Chen proposed a nucleon-pair shell modeI 3,4)
(NPSM). When one restricts the angular momenta byo and 2, the NPSM is reduced to the S D pair shellmodel (SDPM).
Numerical calculation in the SDPM is very timeconsuming (when nuclear pair number N 2: 4). The
reason is that one can not use CFP (coefficients offractional parentage) techniques since the subspace is
not closed. However, we point out that one may use
similar techniques which can be expected to reducethe cpu time drastically. Taking the overlap calculation as an example, since we construct the subspace
using only two kinds of nucleon pairs (i.e., collective
SD pairs), it is not difficult to see that there is only
one pair which goes beyond the subspace in the (N-l)pair overlaps. All the matrix elements with the samebuilding blocks are related to each other via coupling
coeffiGients. Therefore, one needs only a very small

18

part of the (N-l)-pair overlaps in the recursion formulae. Modification of the numerical code is still inprogress.
We have calculated 132Te, 130Te, 128Te, 134Xe,
13 2Xe, 130Xe, 136Ba, 134Ba, and 13 2Ba. The Hamiltonian includes the single-particle term, monopole andquadrupole pairing between like valence nucleons, and
Q-Q force for both like- and unlike-valence nucleons.
We use BeS pair for the S pair, and then construct
D pair by Dt = ~[Q, st]. The calculational results
reproduce the experimental data very well.
Extension of the S DPM to describe odd nuclei isstraightforward. We have developed several algorithms
which are suitable for numerical calculations. The program is under development.
References
1) F. Iaehello and A. Arima: The Interacting Boson
Model, (Cambridge Univ. , 1987).
2) C. L. Wu et al.: Phys. Rev . C 36, 1157 (1987).
3) J. Q. Chen: Nuel. Phys. A 626 , 686 (1990).
4) J. Q. Chen et al.: Nuel. Phys. A 639, 615 (1990).

RIKEN Accel. Prog. Rep. 32 (1999)

The Pseudo-Spin Symmetry in Zr and Sn Isotopes fromthe Proton Drip Line to the Neutron Drip Line t
J. Meng, K. Sugawara-Tanabe, S. Yamaji, and A. Arima[Pseudo-spin symmetry, Relativistic continuum Hartree-Bogoliubov, Drip-line nuclei]
The concept of pseudo-spin was originally found in
spherical nuclei 30 years ago,1,2) but later proved to
be a good approximation in deformed nuclei and remains an important physical concept even in the caseof triaxiality as well.
Since the suggestion of the pseudo-spin symmetry,much efforts has been made to understand its origin.
Based on the single particle Hamiltonian of the oscillator shell model the origin of pseudo-spin was proved tobe connected with the special ratio in the strength of
the spin-orbit and orbit-orbit interactions 3 ) and theunitary operator performing a transformation fromnormal spin to pseudo-spin space was discussed. However, it was not explained why this special ratio is allowed in nuclei. The relation between the pseudo-spinsymmetry and the relativistic mean field (RMF) theory
was first noted in Ref. 4, in which Bahri et al. foundthat the RMF explains approximately the strengthsof spin-orbit and orbit-orbit interactions in the nonrelativistic calculations. In a recent paper Ginocchio
took a step further and revealed that pseudo-orbital
angular momentum is nothing but the "orbital angular momentum" of the lower component of the Dirac
wave function. 5 )By relating the pseudo-spin symmetry back to theDirac equation through the framework of Relativistic
Continuum Hartree-Bogoliubov (RCHB) theory,6) the
pseudo-spin approximation in real nuclei was shown
to be connected with the competition between thepseudo centrifugal barrier (PCB) and the pseudo-spin
orbital potential (PSOP), which is mainly decided by
the derivative of the difference between the scalar andvector potentials. This is general for any Dirac spinors
system with spherical symmetry. With the scalar andvector potentials derived from a self-consistent Relativistic Hartree-Bogoliubov calculation, the pseudospin symmetry and its energy dependence have been
discussed in Ref. 7.
The highly unstable nuclei with extreme proton andneutron ratio are now accessible with the help of theradioactive nuclear beam facilities. The physics connected with the extreme neutron richness in these nuclei and the low density in the tails of their distributions have attracted more and more attention not
only in nuclear physics but also in other fields suchas astrophysics. It is very interesting to investigate

the pseudo-spin symmetry approximation both in normal and exotic nuclei. For this purpose, we use the
RCHB theory, which is the extension of the RMF and
the Bogoliubov transformation in the coordinate representation, and provides not only a unified descriptionof the mean field and pairing correlation but also theproper description for the continuum and its couplingwith the bound state. 6,8,9)
The pseudo-spin symmetry is found to be a good
approximation even for the exotic nuclei with highly
diffused potential. The above conclusion has been well
supported by RCHB calculations for Zr and Sn isotopes from the proton drip line to the neutron drip
line. From the simple Dirac equation, it has beenshown that there are two equivalent ways to solve thecoupled Dirac equation for the upper and lower components: i.e., the normal spin formalism and pseudospin formalism. Both formalisms are equivalent as
far as the energies and wave functions are concerned.
The pseudo-spin symmetry is a good approximation
for normal nuclei and become much better for exotic
nuclei with highly diffuse potentials. The pseudo-spinsymmetry has strong energy dependence. The energy
splitting between the pseudo-spin partners is smaller
for orbitals near the Fermi surface. The lower components of the Dirac wave functions for the pseudo-spin
partners are very similar and almost equal in magnitude. The similarity in the lower components of the
wave function for the pseudo-spin partners near the
Fermi surface is closer than for the deeply bound ones.
References
1) A. Arima, M. Harvey, and K. Shimizu: Phys. Lett. B
30, 517 (1969) .
2) K. T . Hecht and A. Adler: Nuc!. Phys. A 137, 129(1969) .
3) A. Bohr, I. Hamamoto, and B. R. Mottelson: Phys.
Scripta 26, 267 (1982).
4) C. Bahri, J. P. Draayer, and S. A. Moszkowski: Phys.
Rev. Lett. 68, 2133 (1992).
5) J. Ginocchio: Phys. Rev. Lett. 78, 436 (1997).
6) J. Meng: Nuc!. Phys. A 635, 3 (1998) .
7) J. Meng, K. Sugawara-Tanabe, S. Yamaji, P. Ring, and
A. Arima: Phys. Rev. C 58, R628 (1998).
8) J. Meng and P. Ring: Phys. Rev. Lett. 77,3963 (1996).
9) J. Meng and P. Ring: Phys. Rev. Lett. 80, 460 (1998).

Condensed from the article in Phys. Rev. C 59 (1999), in
press

19

RIKEN Accel. Prog. Rep. 32 (1999)

The Pseudo-Spin Symmetry in Relativistic Mean
Field Theoryt
J. Meng, K. Sugawara-Tanabe, S. Yamaji, P. Ring, * and A. Arima[Pseudo-spin symmetry, Relativistic mean field, Relativistic continuum Hartree-Bogoliubov]
The concept of pseudo-spin is that the single particle orbitals with j = l + 1/2 and j = (l + 2) - 1/2 lievery close in energy and can therefore be labelled as
pseudo-spin doublets with quantum number it = n - 1,l = l - 1, and s = s = 1/2. This concept is originallyfound in spherical nuclei,1,2) but later proved to bea good approximation in deformed nuclei as well. 3,4)The origin of pseudo-spin is proved to be connectedwith the special ratio in the strength of the spin-orbit
and orbit-orbit interactions S ,6) and the unitary operator performing a transformation from normal spin to
pseudo-spin space have been discussed. S ) However, it
is not explained why this special ratio is allowed in nuclei. The relation between the pseudo-spin symmetry
and the relativistic mean field (RMF) theory7) was first
noted in Ref. 8. In a recent paper Ginocchio taked a
step further and revealed that pseudo-orbital angularmomentum is nothing but the "orbital angular momentum" of the lower component of the Dirac wave
function. 9 )He also built the connection between the pseudospin symmetry and the equality in the scalar and vector potentials. Here we will show that the quality ofpseudo-spin symmetry is connected with the competition between the centrifugal barrier (CB) and thepseudo-spin orbital potential (PSOP), which is mainly
decided by the derivative of the difference between thescalar and vector potentials.
Here the Relativistic continuum Hartree-Bogoliubov(RCHB) theorylO) has been used for the present investigation. As this theory takes into account the proper
isospin dependence of the spin-orbit term, it is able
to provide a good description of global experimental
data not only for stable nuclei but also for exotic nuclei throughout the nuclear chart.ll) Starting from the
RCHB, instead of assuming the equality in magnitudeof the scalar and vector potentials, we treated the equation exactly and obtained a general formalism leading
to the pseudo-spin symmetry.
We use the non-linear Lagrangian parameter set
NLSH 12 ) which could provide a good description of all
nuclei from oxygen to lead. As we study not only theclosed shell nuclei, but also the open shell nuclei, theinclusion of the pairing is necessary. The pairing interaction is the same as Ref. 13. As shown in Ref. 11, theparticle levels for the bound states in canonical basis
are the same as those by solving the Dirac equation
Condensed from the article in Phys. Rev. C 58, R628 (1998)
Technische Universitat Miinchen, Germany

20

with the scalar and vector potentials from RCHB.
In conclusion, the pseudo-spin symmetry is examined in realistic calculation in the framework of RCHB
theory. We have proved that if dV/ dr = 0 is satisfied, the pseudo-spin symmetry is exact. Further, the. .
1 ~ dV~(1 - ~) .
new condItIOn - E
V - -d«2
IS found under
-

r

r

r

which the symmetry is preserved approximately. We
have examined under this condition how good approximation the pseudo-spin symmetry is in RCHB. For agiven angular momentum and parity channel, the ef~(~ -1)fective CB, (E - V)2
' becomes stronger for therless bound level, so the pseudo-spin symmetry for the
weakly bound state is better than that for the deeply
bound state, which is in agreement with the experimental observation. 1,2) The pseudo-spin symmetry isfound to be a good approximation even for exotic nuclei. The above conclusion has been well supported by
the examples of 88Z r and 120Zr. From the simple Diracequation, it has been shown that there are two equivalent ways to solve the coupled Dirac equation for theupper and lower components: i.e., the normal spin formalism and pseudo-spin formalism. Both formalisms
are equivalent as long as the energies and wavefunctions are concerned.
References
1) A. Arima, M. Harvey, and K. Shimizu: Phys. Lett. B
30, 517 (1969).
2) K. T. Hecht and A. Adler: Nucl. Phys. A 131, 129(1969) .
3) R. D. Ratna Raju, J. P. Draayer, and K. T. Hecht:
Nucl. Phys. A 202, 433 (1973); J. P. Draayer and K. J.
Weeks: Ann. Phys. (N. Y.) 156,41 (1984).
4) J. Y. Zeng et al.: Phys. Rev. C 44, R1745 (1991).
5) A. Bohr, I. Hamamoto, and B. R. Mottelson: Phys.
Scripta 26, 267 (1982).
6) O. Castanov, M. Moshinsky, and C. Quesne: Phys. Lett.
B 211, 238 (1992).
7) B. D. Serot and J. D. Walecka: in Advances in Nuclear
Physics, edited by J. W. Negele and E. Vogt, Vol. 16(Plenum, New York, 1986) p. 1.
8) C. Bahri, J. P. Draayer, and S. A. Moszkowski: Phys.
Rev. Lett. 68 , 2133 (1992).
9) J. Ginocchio: Phys. Rev. Lett. 18, 436 (1997).
10) J. Meng and P. Ring: Phys. Rev. Lett. 11,3963 (1996).
11) J. Meng: Nucl. Phys. A 635, 3 (1998).
12) M. Sharma, M. Nagarajan, and P. Ring: Phys. Lett. B
312, 377 (1993).
13) J. Meng and P. Ring: Phys. Rev. Lett. 80,460 (1998).

RIKEN Accel. Prog. Rep. 32 (1999)

The Pseudo-Spin Symmetry in Dirac Equation
K. Sugawara-Tanabe, J. Meng, S. Yamaji, and A. Arima[Pseudo-spin symmetry, Deformed Dirac equation]
The origin of the pseudo-spin symmetryl) has been
investigated with the purpose to find its root to therelativistic Dirac equation. 2- 4 ) By extending Ginnocchio's method,2) we found the more general and realistic condition for the hidden symmetry of pseudo-spin
approximation in the lower component (f) of Dirac
wave function in the spherical potentials. 3 ,4) The Diracequation for a nucleon with mass M moving in thevector potential (Vv (T)) and scalar potential (Vs (r))
is given by,[a· jJ + Vv(f) + (J(M + Vs(T) )]'l/J(f) = E'l/J(r).

(1)

Here a and (J are Dirac matrices. The spinor 'l/J(f) is
composed of the upper component (g) and the lower
component (i). In the spherical potential case, thesetwo components 9 and i are decomposed into the product of the radial part and the vector spherical harmonics with quantum numbers j, and jz, where j is the
single-particle angular momentum and is its orbital
angular momentum.
Now we extend our theory to the deformed case withaxially symmetric shape. In this case j is no longer agood quantum number, but there still remains a symmetry around the symmetry axis z characterized by
jz = O. We use the cylindrical coordinate (r 1., z, cp) tosolve the Dirac equation. Each of 9 and f has now twocomponents,eewhere E = E-M, VI = E- V, V2 = E+2M* - V with
V = Vv(T) + Vs(f) and M* = M + Vs(f). The coupledequations between g~ and g::' are given by exchanging
f~ by g~, and VI by V2 and vice versa. In the nonrelativistic theory, the levels labeled by (e z = A, SZ =1/2,jz = 0) and by (e z = A + 2, Sz = -1/2,jz =0+ 1) become the pseudo-spin pair of (lz = A + 1, Sz =-1/2,jz = 0) and (lz = A + 1, Sz = 1/2,jz = 0 + 1).
Comparing Eqs. (3) and (4), we find that is: and i::'+ 1
become pseudo-spin doublets as long as oV1 / 8r 1. = 0
and oVI/8z = O. Thus, we find the condition for thepseudo-spin symmetry in the deformed potential as(a) 8VI = 0,oz

oV1 - O·
Or 1.. - ,

(5)

(2)

(6)

Here i~ and g~ are the functions of r 1. and z , and± corresponds to ±1/2 of Sz. Inserting Eq. (2) into
Eq. (1) and eliminating f~ (g~), we get the coupledequations between g~ and g~ and also between f~ andf:3. Here we show the coupled equations for f + andf:!·

By applying the similar technique used in the spherical potentials, we found the condition for the hiddensymmetry of pseudo-spin in deformed nuclei for the
first time. The condition (a) in Eq. (5) is not always
satisfied in the real nuclei, but (b) in Eq. (6) is a moreplausible condition. Our next work is to evaluate (b)in Eq. (6) for the deformed nuclei with a realistic parameter set similar to the spherical case shown in Refs.
3 and 4.

2
0 f~ _ (0 - 1/2)2 fn
ori
+

ri

1 of~

02f~

+ - + -oz2r 1. or 1.

References~ oVI (Of~ _ 0 - 1/2 fn _ Of:!)VI Or 1. Or 1.

r 1.

+

0Z

~ oVI (Of:! + 0 + 1/2 f~ + Of~),
VI oz

or J..

r J..

oz

(3)

1) A. Arima, M. Harvey, and K. Shimizu: Phys. Lett. B
30, 517 (1969).
2) J. N. Ginocchio: Phys. Rev. Lett. 78,436 (1997).
3) J. Meng, K. Sugawara-Tanabe, S. Yamaji, P. Ring, and
A. Arima: Phys. Rev. C 58, R632 (1998).
4) J. Meng, K. Sugawara-Tanabe, S. Yamaji, and A.
Arima: Phys. Rev. C 59, 154 (1999).

21

RIKEN Accel. Prog. Rep. 32 (1999)

Triaxial Deformation of Medium Heavy Nuclei in Relativistic
Mean Field Theory with Pairing Correlation
S. Sugimoto, K. Sumiyoshi, D. Hirata, 1. Tanihata, and H. Toki
[Relativistic mean field theory, Triaxial deformation, Pairing]
We study the properties of medium heavy mass nuclei including the possibility of triaxial deformation in
the relativistic mean-field theory with pairing correlation. We calculate the energy surfaces of the even-evennuclei around 122Xe in the (3-, plane on the Fujitsu
VPP500/28 Supercomputer of the Computation Center in RIKEN.
The relativistic many body theory has been extensively applied to nuclei and nuclear matter with remarkable successes in recent years. The relativistic
mean-field (RMF) theory has been employed in large
scale to study the properties of stable and unstable
nuclei. The description of the ground state properties of stable and unstable nuclei with axial deformation in terms of the RMF has been found to bevery satisfactory. 1) However, it was found necessary
to extend the theory to include higher order deformations. In many cases, the axial symmetric calculations
give minima on both the prolate and oblate shapeswith energies very close to each other. In those cases,
the ground state configuration cannot be well distinguished and the shape coexistence or another typeof deformation should be also explored. The inclusion of triaxial deformation(r degree of freedom) to
the RMF approach was worked out and applied to
study the properties of light mass sulfur nuclei. 2) It
was found a smooth transition from prolate to oblate
shapes through triaxial shapes and eventually to thespherical shape. Similar behavior can be expected inother region of the nuclear chart. Here, we applied thisframework to the medium heavy region around 122Xe.
We found that in this region many nuclei have the possibility of the triaxial shapes in their ground state. We
also found the smooth shape transitions in the sulfur
region.
However, in those calculations we did not take into
account the effect of pairing correlations. This correlation may have large effect on nuclear deformations. We
include it in the calculation of the triaxial deformationin terms of the BCS theory. We use the extended RMF
theory which include the triaxial deformation degreeof freedom. The theory contains the meson masses,
the meson-nucleon coupling constants, and the meson
self-coupling constants as free parameters. The calculations are carried out using the parameter set TMA,
which was determined by fitting the experimental dataof masses and charge radii of nuclei in a wide mass
range, so as to reproduce nuclear properties quantitatively in the entire mass region. 3 ) The wave functions

22of nucleons and mesons are expanded in terms of theeigenfunctions of an triaxially deformed harmonic oscillator potential. The expansion method is describedin detail in the paper by Gambhir et al.,2,4) but one
more degree of freedom (r deformation) is included
newly.2) In the present calculation, we work with basisof the 12 major shells for fermions and 10 major shells
for bosons. In order to obtain the energy surfaces,
we perform the quadratic constrained calculations on
the quadrupole moments of nucleon distribution, Q20
and Q22.2 ,5) In the pairing channels we use the BCS
scheme by the constant gap approach. We note that inthis scheme pairing correlations are not treated on the
ground of relativistic framework. We are now investigating the theory which treats the pairing correlations
consistent with the relativistic framework.
We shall show one result. Figure 1 shows the energy surface of 124Xe in {3-, plane. The horizontal
axis (, = 0°) denotes the prolate shape and the tilted
axis (, = 60°) denotes the oblate shape. The region
among these axes denotes triaxially deformed shape.
The larger value of {3 indicates the stronger defomation. The energy difference between the contour isabout 1 MeV. In Fig. 1 the position of the absolute
minimum is denoted by the black area. From the Figure we see 124Xe has the axial deformed shape in the
ground state. The other nuclei are still under study.

,=60

0.0

0.1

0.2

0

0.3

0.4

/3
Fig. 1. The energy surface in the (3-, plane of 124Xe.
The positon of the absolute minimum is denoted by theblack area.
References
1) D. Hirata et al.: Nucl. Phys. A 616, 438c (1997) .
2) D. Hirata et al.: Nucl. Phys. A 609, 131 (1996).
3) Y. Sugahara: Doctor thesis, Tokyo Metropolitan University (1995).
4) Y. K. Gambhir et al.: Ann. Phys. 198, 132 (1990) .
5) H. Flocard et al.: Nucl. Phys. A 203, 433 (1973).

RIKEN Accel. Prog. Rep. 32 (1999)

SU(3) Symmetry in Oblate and Triaxial Nuclei
K. Sugawara-Tanabe and A. Arima[SU(3) symmetry, Oblate deformation, Triaxial shape]
We have previously shown that the new dynamical
SU(3) symmetry exists at the prolate deformed nuclei
when the two harmonic oscillator frequencies W..l andW z have the rational ratio. 1) In this paper we show that
we can similarly extend our discussion to the oblate
deformed nuclei and also to the triaxial shaped nuclei.
We adopt the harmonic oscillator Hamiltonian witha rational ratio a : b : c between three frequencies
W x , wyand W z . Then the energy eigenvalue becomesnWsh(Nsh + (a+b+c)/2) with the shell quantum number Nsh = an x + bny + cn z and the shell energy nWsh.
At first we consider the case of oblate superdeformation, in which Wx : Wy : W z = 1 : 1 : 2, and the deformation parameter () = 3(a - c)/(2a + c) = -0.75. We
construct new boson operators d and dt as a biproductof the harmonic oscillator bosons, c± and c~, wherec± = =t= (c x =t= cy)/ V2. Because of the biproduct of
c± , we have two kinds of bosons corresponding tond = n±/2 or nd = (n± - 1)/2:
d=

1

2

)2(1 + n±) c±,

d=

1

(1)

2

)2(2 + n±) c±,

where n± = c~c±. Both bosons do not mix each otheras they belong to different N sh . We obtain a new set ofgroup operators, and Pin the same way as in the prolate superdeformed case. In contrast to Elliott's case 2 )where ±2nwo excitations are excluded, our group operators exclude ±2nws h excitations. Moreover, this new
SU(3) has a dual nature because of two kinds of bosons.
Then we can summarise the clasification of the singleparticle states in a superdeformed oscillator ofand
Pz , which becomes completely the same as shown in
Table 1 in Ref. 1. Similarly, we can get the same classification of the single-particle levels for the case ofa : b : c = 1 : 1 : 3 as a : b : c = 3 : 3 : 1 inprolate hyperdeformation. In this case we introduce
three kinds of g-bosons corresponding to ng = n±/3
or ng = (n± - 1)/3 or ng = (n± - 2)/3:

0

00

g=

1

In this case SU(3) is triplicate. Similarly we can get
the same classification for a : b : c = 2 : 2 : 3 as a : b :c = 3 : 3 : 2, in which SU(3) has six-fold degeneracy. In
this case we adopt 9 bosons for ± axis and d bosons forz axis. Thus, we can conclude that there exists SU(3)symmetry even in the oblate deformation as long as
two frequencies have rational ratios.
Now we consider the triaxial case with a : b : c =1 : 2 : 3. We use 9 bosons for the x axis (c± in (3)should be replaced by cx ), d bosons for the y axis (c± in(2) should be replaced by cy ), and the usual harmonic
oscillator boson C z for the z axis. The Casimir operator
becomes,c = 2(ng + nd + nz)(ng + nd + n z + 3).

(3)

Although it has the nature of SU(3) for the triaxial
case with rational ratio of three frequencies, but there
is no degeneracy of SU(3) in different Nsh. Moreover,the single-particle levels are qualified only byand
Pz is no longer diagonal in this representation. Instead
we can use+= V6(ng - nd) as a order oftriaxiality. We can summarize the classification of thesingle-particle levels in the Table 1.

00,

02 0-2

Table 1. Single particle levels for triaxial (a : b : c = 1 : 2: 3) shape.
Nsh

0
1

2
3

4

ng
0
0
0
1
0
0
1
0
0
0

nd
0
0
0
0
0
0
0
0
0
0

nz
0
0
0
0
0
1
0
0
1
1

<c>

< Qo >

0
0
0
8
0
8
8
0
8
8

0
0
0
-1
0
2
-1
0
2
-1

3

)3(n± + 2)(n± + 1) c±,

Referencesg=13)3(n± + 3)(n± + 1) c±)

9 =~==============c±.

I} K. Sugawara-Tanabe and A. Arima: Nucl. Phys. A 619,
88 (1997).
2) J. P. Elliott: Proc. Roy. Soc. A 245, 128 (1958); 245,
562 (1958).

1v3(n± + 3)(n± + 2)

3

(2)

23

RIKEN Accel. Prog. Rep. 32 (1999)

Relativistic Mean Field Investigation of the Identical Bands andBand Crossing in the Superdeformed Eu-Gd Nuclei
H. Madokoro, J. Meng, M. Matsuzaki, and S. Yamaji[Relativistic mean field, Identical band, 148Eu, 149Gd]
8 new superdeformed(SD) bands in 148Eu were discovered in recent experiment,!) some of which havenearly identical transition energies and therefore identical moments of inertia to those in 149Gd, that is,they form the so-called identical bands. In addition,
there is another interesting observation of the 7r6 1-7r6 3band crossing which is the first experimental observation of this crossing. As for the identical bands, there
have been so many experimental observations of theidentical pairs in the A rv 130, 150 and 190 mass regions. From the theoretical side, there have been several attempts to explain the mechanism of these identical bands, for example, the one using the concept ofpseudo-spin symmetry.2) Why the transition energiesof these two bands become so identical within an accuracy of 0.1%, however, is still under debate.
In 1993, Munich group proposed a new explanationof the identical bands within the context of Relativistic Mean Field (RMF) model. They calculated thelowest SD band in 152Dy and one of the excited SD
bands in 151Tb which form the identical pair of bands.
In addition to the usual calculation, they performed
two types of calculations, one with neglecting the polarization effect induced by the neutron hole, anotherone with neglecting the effect of the space componentsof the vector mesons (nuclear magnetism). Both calculations did not give the identical transition energies
but acted in the opposite direction with approximately
the same magnitudes. Finally they concluded that acancellation occurred between the effect of the polarization and that of the nuclear magnetism, resulting
in the nearly identical transition energies .. Up to now,
this new mechanism has been examined only for thepair of 152Dy_151Tb nuclei. To see whether this mechanism is a general one or not , it is necessary to performthe same calculations for other pairs of bands. Therefore, as a first step, we investigate the identical pair of
148Eu_ 149 Gd nuclei , including recently discovered SD
bands in 148Eu, using RMF model.
RMF model contains nucleons and several kinds ofmesons as basis components. Starting from the Lagrangian containing these degrees of freedom, we canderive the equations of motion for nucleons and mesons
after applying the variational principle. In the application to rotating nuclei, we combine the RMF modeland the cranking assumption. Then the Lagrangianin the laboratory frame is generalized to the uniformly
rotating frame, from which the equations of motion in24

this frame are derived. For detail, see Refs. 3 and 4.
In the numerical calculations, the parameter set NLI
is adopted. At first we calculate the moments of inertia of the lowest SD band in 14 9Gd and the lowest two
SD bands in 148Eu. Apart from small deviations atlower frequencies, we obtain good agreements between
the calculated and the experimental values. Besides,
we find that the moments of inertia( or equivalently
the transition energies) become nearly the same values between 149Gd and 148Eu. Next, we perform two
different kinds of calculations following the previous
investigation of Munich group. (1) We calculate theSD bands in 148Eu using the wave functions of 149Gd,
without assuming self-consistency. This corresponds tothe calculation neglecting the effect of the polarizationinduced by a neutron hole. The resulting transition energies do not become identical at all. (2) We perform
a self-consistent calculation of the SD bands in 148Eu,
but the space components of the vector mesons, are neglected. Again the transition energies in this case do
not become the same. We find that, contrary to thecase of 152Dy_151Tb pair, both effects act not in the opposite direction but in the same direction. Thus a cancellation between (1) and (2) does not occur. It should
be noticed that the usual calculation where both thepolarization effect and the nuclear magnetism are included does give the identical transition energies, as westated before. This implies that the usual calculation
is not a simple summation of (1) and (2), and there
may be other effects which also contribute to the difference of the transition energies. Including these othereffects, together with (1) and (2), will finally lead tothe identical transition energies. Anyway we can saythat the cancellation between the effect of the polarization and that of the space components of the vector
mesons does not occur in the case of 149Gd_148Eu pair.
Clearly it is necessary to perform further systematicinvestigations to give a definite conclusion, and suchinvestigations in this mass region, together with thoseof the 7r6 1- 7[6 3 band crossing, are now in progress.
References
1) D. S. Haslip et al.: Phys. Rev. C 57, 2196 (1998).
2) W . Nazarewicz, P. J. Twin, P. Fallon, and D. Garrett:Phys. Rev. Lett. 64, 1654 (1990).
3) W. Koepf and P. Ring: Nucl. Phys. A 493, 61 (1989).
4) H. Madokoro and M. Matsuzaki: Phys. Rev. C 52,
R2934 (1997).

RIKEN Accel. Prog. Rep. 32 (1999)

Band Structures of 1820s Studied by GCM Based on 3D-CHFB
T. Horibata, M. Oi, N. Onishi, and A. Ansari*1,*2[Tilted rotation, Generator coordinate method, ,),-deformation]
We have carried out the angular momentum
and particle number constrained generator coordinate method{ GCM) calculations based on the threedimensional cranked Hartree-Fock-Bogoliubov approach (3D-CHFB). Compared to our previous
works, 1,2) we have refined the force parameters carefully so as to reproduce the characteristic features ofthe yrast states for the mass region of interest. With
our new set of force parameters the neutron gap parameter ~n vanishes almost, whereas the proton gap
parameter ~p survives still with the size of the groundstate one at J = I8h. In our calculation the bandcrossing occurs at J = 20h. After choosing the setof force parameters we have performed the 3D-CHFB
calculation along the prime meridian on the globe of
J = I8h sphere. We know from our previous study
that a calculation along the prime meridian always
gives a lower energy compared with the calculation
performed on the whole surface of the globe. Like theprevious calculation, we have confirmed the existenceof a stable tilted axis rotating(TAR) potential curve forthis time also. The TAR minimum appears at 'I/J = 24°.
Furthermore, we have found a negative potential curvenear the north pole. We have performed the GCM
calculation based on this new potential curve and discussed properties of the band structure of 182 Os. The
results can be summarized by stressing following threepoints.
First point is that by including the constrained terms
in the Hill-Wheeler equation the stability of the solutions is much increased and we can recognize in the
GCM solutions the appearance of wide-range plateaus
even in such a high angular momentum region as
J = I8h. This was not the case in our previous work.
The reason is that we can suppress a drift of the meanvalue of the square of angular momenta by the constrained term in the Hill-Wheeler equation and canprevent a contamination by the lower angular momentum components that are present in the cranking wave
function.
Second point is that from the symmetry propertyof the lowest GCM solution we can expect that this*1
*2

nucleus should be a tilted-rotor at J = I8h yrast state.
The tilt angle is about 'I/J = 12°. As discussed in Ref. 3
the TAR potential minimum will not be a necessary
condition for an occurrence of the tilted axis rotation. In our approach, only the GCM solutions canproperly predict the characteristic features of exotic
collective motions. In the fourth and sixth solutions
we have found an s-band character in the principal
axis rotational(PAR) region. We have found a signof multi-band mixing in this nucleus. If the sn-bandstates, such as the fourth or sixth solutions, come into
energetically-lower positions in the higher angular momentum region, we can say that the band mixing4)
will become a key concept in understanding the band
structure of the nucleus.
The last point is that we have found the new 3DCHFB solutions along the prime meridian, which havebeen obtained by the tilt-back calculation at J = I8h
state. From the characteristic features of the solution, we can say that a new type of seesaw vibrationalmode of the proton and neutron pairing occurs in the
backbending region in 182 Os. This mode accompanies a large ,),-oscillation. Thus, a wobbling motion
is expected to mediate a band crossing between theg- band and s-band in this nucleus. The GCM calculation which includes these new solutions to explore
the band structure of A
180 mass region will be thenext attractive subject. The preliminary results will
be appeared on Ref. 5 and the detailed discussions are
given in Ref. 3.
I"VReferences
1) T. Horibata, M. Oi, and N. Onishi: Phys. Lett. B 355,
433 (1995) .
2) T. Horibata and N. Onishi: Nucl. Phys. A 596, 251(1996) .
3) T. Horibata, M. Oi, N. Onishi, and A. Ansari: Nucl.
Phys. A 646, 277 (1999) (RIKEN-AF-NP-297).
4) P. M. Walker: Proc. Future of Nuclear Spectroscopy,
Crete (1993).
5) T. Horibata, M. Oi, and N. Onishi: J. Phys. G 25, 1(1999) (RIKEN-AF-NP-287).

Institute of Physics, Graduate School of Arts and Sciences,
University of Tokyo
Institute of Physi~s, Doordarshan Marg, India

25

RIKEN Accel. Prog. Rep. 32 (1999)

Width and Shape of the Hot Giant Dipole Resonance
N. Dinh Dang, K. Tanabe, and A. Arima[Single-particle levels, Thermal and statistical models, Giant resonances]
We have developed an approach to study the widthand shape of the GDR at various temperatures, which
includes all the forward-going processes up to twophonon ones in the second-order of the interaction
strength. The present paper shows that: (1) the total width r GDR of the hot GDR arises mainly fromthe coupling of the GDR vibration to all ph, pp andhh configurations. It increases sharply as temperature
increases up to T "-' 3 MeV. At higher temperatures
the width increase is slowed down to reach a saturated
value of around 12 MeV in 120Sn and around 10.5 MeV
in 208Pb at T,,-, 4- 6 MeV; (2) the quantal width rQ of
the GDR due to coupling of GDR vibration to only phconfigurations decreases as T increases. Neglecting thetwo-phonon processes in the expansion to higher-orderpropagators results in a quantal width, which is almost independent of T; (3) the calculated GDR shapein our model agrees reasonably well with the data. The
numerical calculations are limited within a schematiccase whose parameters were selected to reproduce theempirical values of the GDR width and its energy at
T = O. More refined microscopic studies in this direction are highly desirable since the actual complexity of
the wave functions can clarify in detail the relationship26

between the eigenstates of the model Hamiltonian andthe representation basis, and, therefore, may shed
more light on the physics of the problem. Other ingredients such as the temperature dependence of thesingle-particle energies, the contribution of the evaporation width at high temperatures, and the effects ofhigh values of the angular momentum have been also
left out in the present study. While there have beensome indications on that these effects may not be crucial within the temperature region under consideration
and/or in nuclei with mass number A 2: 120, they certainly deserve thorough studies in the future.
More details about our study of the hot GDR canbe found in the series of our papers in Ref. 1.
References
1) N. Dinh Dang and A. Arima: Phys. Rev. Lett. 80,
4145 (1998); Nucl. Phys. A 636, 443 (1998); N. Dinh
Dang, K. Tanabe, and A. Arima: Phys. Rev. C 58, 3374
(1998); Nuel. Phys. A 645 , 536 (1998); N. Dinh Dangand F. Sakata: Phys. Rev. C 55, 2872 (1997) ; Phys.
Rev. C 57, 3032 (1998) ; N. Dinh Dang: Phys. Rep.
264, 123 (1996); N. Dinh Dang: Nuel. Phys . A 504,
143 (1989).

RIKEN Accel. Prog. Rep. 32 (1999)

Contribution of Higher-Order Processes to the Dampingof Hot Giant Dipole Resonance t
N. Dinh Dang, K. Tanabe, and A. Arima[Single-particle levels, Thermal and statistical models, Ciant resonances]
The giant dipole resonance (CDR) is one of the mostspectacular and best known responses of nuclei. It is
generated by collective motion of protons against neutrons in the nucleus. Apart from the GDR built on the
ground state (g.s. GDR) , the CDR built on compound
nuclear states (hot GDR) has been the subject of aconsiderable number of experimental and theoreticalstudies during the last fifteen years.
Recently we have proposed an approach to the widthof the hot GDR, which has shown that the couplingof the collective dipole vibration (GDR phonon) to
the incoherent particle-particle (pp) and hole-hole (hh)configurations appearing at non-zero temperature (thethermal damping) is responsible for the width increaseat low temperature T and its saturation at high T.
It has also been concluded that the quantal damping due to coupling only to ph configurations decreases
slowly as the temperature increases. The applicationof this approach to a systematic study of the quantal and thermal dampings of the hot GDR in 90Zr,
120S n , and 208Pb has shown a reasonable agreementwith the experimental data. 1) In this work a systematic study is presented for three characteristics of the
giant dipole resonance (GDR): (1) its width, (2) its

shape and (3) the integrated yield of emitted I rays in
120Sn and 208Pb as a function of temperature T. The
double-time Green function's method has been used toderive a complete set of equations, which allows us tocalculate explicitly the GDR width due to coupling to
all forward-going processes up to two-phonon ones atmost in the second order of the interaction strength.
An overall agreement between theory and experimentis found for all the three characteristics. The results
show that the total width of the GDR due to couplingof the GDR phonon to all ph, pp and hh configurations
increases sharply at low temperatures up to T "-' 3 MeV
and saturates at T "-' 4-6 MeV. The quantal width rQ
due to coupling to ph configurations decreases slowly
with increasing T. It becomes almost independent of
T only when the contribution of two-phonon processes
at T i= 0 is omitted. The observed saturation of theintegrated yield above E* "-' 300 MeV is reproduced inboth the GDR region and in the region above it.

References
1) N. Dinh Dang and A. Arima: Phys. Rev. Lett. 80, 4145
(1998); Nucl. Phys. A 636, 443 (1998).

Condensed from the article in Phys. Rev. C 58, 3374 (1998)

27

RIKEN Accel. Prog. Rep. 32 (1999)

Damping of Hot Giant Dipole Resonance Due to Complex
Configuration Mixing
N. Dinh Dang, K. Tanabe, and A. Arima[Single-particle levels , Thermal and statistical models, Giant resonances]
A central problem in the study of giant dipole resonance (GDR) in highly-excited nuclei (hot GDR) during the last fifteen years has been the behavior of the
GDR width and shape as a function of temperature T.
The main part of the total GDR at T = 0 width comesfrom the spreading width due to coupling to complicated configurations such as 2p2h and even more complex ones. It turns out that the spreading width depends weakly on T within the extension of well-known
microscopic theories to non-zero temperature. 1) This
contradicts the experimental systematic which showsa rapid increase of the full width at half maximum(FWHM) at low excitation energies E* (or T) . At
higher E* the width increases slowly and even saturates at E* 2: 130 Me V in Sn isotopes. It has been
pointed out that not only the FWHM and energy, butalso the complete shape of the GDR should be considered to achieve a meaningful comparison between
theory and experiment. The saturation of the yield of, rays at E* 2: 300 Me V also requires further studies
to give an adequate answer on the persistence or disappearance of the GDR at high T. Recently we haveproposed a microscopic approach to the damping of
the hot GDR,2) which shows that the coupling of the28collective dipole vibration (GDR phonon) to particleparticle (pp) and hole-hole (hh) configurations appearing at T =I- 0 is decisively important for a consistentdescription of the width's increase and its saturation.
This work presents for the first time a complete approach, including explicitly all the forward-going processes up to two-phonon ones at T =I- O. Its application
will address all three issues: (1) the GDR width, (2)its shape and (3) ,-ray yield in l20Sn and 208Pb. The
calculated total width, strength function and the integrated yield of, rays of the GDR in 120Sn and 208Pb
are found in reasonable agreement with the data. Including two-phonon processes, the quantal width r Q
due to coupling to ph configurations alone decreases
with increasing T. It is shown that the GDR still persists up to T rv 6 MeV.

References
1) P. F. Bortignon et al.: Nuel. Phys. A 460 , 149 (1986);
N. Dinh Dang: Nuel. Phys. A 504, 143 (1989).
2) N. Dinh Dang and A. Arima: Phys. Rev. Lett. 80,4145(1998); Nue!. Phys. A 636, 443 (1998).

RIKEN Accel. Prog. Rep. 32 (1999)

Shape Evolution of the Hot Giant Dipole Resonance t
N. Dinh Dang, K. Tanabe, and A. Arima[Single-particle levels , Thermal and statistical models, Giant resonances]
A systematic description of the evolution of the giant
dipole resonance (GDR) at non-zero temperature T isgiven within the framework of two versions PDMl 1)
and PDM2 2) of the Phonon Damping Model (PDM).

The numerical calculations have been performed for
the GDR width, the strength function and the integrated yield of the ! rays in 120S n and 208Pb ato ::; T ::; 6 MeV. The results obtained agree reasonably

1.0
'0

0.8

(a) T=1.24 MeV

120Sn(c) T=2.61 MeV

120Sn(b) T=2.02 MeV

120Sn(d) T=3.12 MeV

120Sn

x 0.6

:>
Q)

e, 0.4
~

~

CI)

0.2
0
1.0

b

0.8

x 0.6
>
Q)

6

0.4

~

w
(j)

0.2
0
5

10

15
Ey (MeV)

20

25

30

5

10

15
Ey (MeV)

20

25

30

Fig. 1. GDR strength function in 120Sn calculated within PDM-1 at several temperatures. Solid:
results obtained with the effect of single-particle damping. Dashed: results without the effect of
single-particle damping. Diamonds: inelastic a-scattering data adapted in Ref. 3.

well with the most recent experimental data for allthese three characteristics including the saturation of
the yields within the GDR region and in the region
above it. An example is shown in Fig. 1. Predictions
have been made for the GDR shape in both nuclei at
T up to 6 Me V and for the integrated yield of ! rays
in 208Pb.

References
1) N. Dinh Dang and A. Arima: Phys. Rev. Lett. 80,4145(1998) ; Nucl. Phys. A 636, 443 (1998).
2) N. Dinh Dang, K. Tanabe, and A. Arima: Phys. Rev.
e 58, 3374 (1998).
3) T . Baumann et al.: Nucl. Phys. A 635, 428 (1998).

Condensed from the article in Nuel. Phys. A 645, 536 (1998)

29

RIKEN Accel. Prog. Rep. 32 (1999)

Damping of Double Giant Dipole Resonance
N. Dinh Dang, K. Tanabe, and A. Arima[Giant resonances, Thermal and statistical models, Relativistic heavy-ion collision]
An unambiguous signature of the double giant dipole
resonance (DGDR) has been obtained in pion-induced
charge exchange reactions and in relativistic heavy-ion
reactions via Coulomb excitation. 1) In the harmonic
picture a multiphonon excitation is considered as composed of independent phonons. Hence, the energy ofa multiphonon state is just the sum of energies of theconstituting single-phonon (boson) states. In reality
the main features of the observed DGDR can be summarized as follows. (1) The energy E DCDR of the
DGDR is about twice as large compared to the giant
dipole resonance (GDR): EDcDR ~ 2EcDR, i.e. welldescribed by the harmonic picture. (2) The observed
width r DC DR of the DGDR is in between J2r CDR
and 2r CDR, where r CDR is the GDR width. (3) The
magnitude of the measured total electromagnetic excitation cross section is found to be enhanced up to
more than three times larger than the one obtained in
the harmonic limit, depending on nuclei.
In this work a microscopic approach is proposed tothe damping of the DGDR. The double-time Green's
function method is used to derive a closed set of
coupled equations for the propagation of two-phonon

30

excitation through the field of incoherent nucleon pairs.
The analytical expressions for the width and energy
shift of the DGDR are obtained. The numerical calculations are performed for 90Zr, 90Sn, and 208Pb forseveral characteristics of the DGDR at zero as well
as nonzero temperatures T. The results are foundin reasonable agreement with existing experimental
systematics for the width and energy of the DGDR.
As compared to the estimation within the harmonic
picture, the anharmonicity leads to a noticeable enhancement of the integrated photoabsorption cross section (IPACS) over the DGDR region. The DGDR
width is found to increase sharply with increasing T at
T ::; 3 MeV, but comes to a saturation at T > 3 MeV.
The harmonic limit for the DGDR width is restored
already at T 2: 1.5 MeV. It is shown that the IPACSof the DGDR can also be enhanced compared to its
harmonic value if it is built on a hot GDR.
References
1) S. Mordechai et al.: Phys. Rev. Lett. 61, 531 (1988);
H. Emling: Part. Prog. Nucl. Phys. 33, 629 (1994); K.
Boretzky et al.: Phys. Lett. B 384, 30 (1996).

RIKEN Accel. Prog. Rep. 32 (1999)

Reaction Cross-Sections in the -Quantum Molecular
Dynamical Approach
T. Maruyama[Reaction cross-section, QMD]
Radii of exotic nuclei are experimentally determinedfrom measuring reaction cross-sections a R in nucleusnucleus collisions using the equation as(JR =K(Rp + RT)2,

Root-Mean-Square Radii(1)

where Rp and RT indicate projectile and target radii,
respectively. This equation is, however, satisfied only
for collisions above several hundred MeV lu, where
the elementary N N cross-section does not have strong
energy-dependence, and the trajectory of a projectile
nucleus is well approximate to be straight.
On the other hand we need to make theoretical analysis of experimental results with the beam energy below 100 MeV lu, where a lot of data is available fromRIKEN. In this calculation we must consider effects
of energy-dependence of the N N cross-section andcurved trajectory of initial nuclei in reaction around50- 100 MeV I u energy region.
The Quantum Molecular Dynamics (QMD)
approach 1 ,2) must be a powerful theoretical method forthis purpose. This approach is a semi-classical numerical simulation including a mean-field and elastic andineleastic N N collisions, and it can give consistent results in wide energy region: from several ten MeV lu
to several GeV lu. Furthermore this approach havesuccessfully explained many kinds of experimental results in nucleus-nucleus collisions,l) proton-induced
reactions,2) and so on. In this work we make initial
nulcei with correct root-mean-square radii while one
has not carefully treated them, and examine reaction
cross-sections in the QMD approach.
First we determine parameters of a mean-field togive correct root-mean-square radii of ground state
nuclei where each nucleon moves feeling force fromother nucleons. Figure 1 shows calculation results oftime-averaging root-mean-square radii of several nulcei, whose binding energies are given as experimental
data.
As a next step we calculate energy-dependencs of reaction cross-sections in the QMD approach. We definea reaction event where one N N collision occures, andevaluate the reaction cross-section by summing reaction probabilities for all impact-parameters.
In Fig. 2 we draw target-mass-number dependence ofreaction cross-sections for the carbon beam at 83 and300 MeV lu. We can see that the QMD approach nicely
reproduce exerimentl results 3 ) even below 100 Me V lu.
Then we can conclude that our approach is effective forthe present purpose. Now we are testing reactions with

-

~
....

4 r

-

"v 2 ro- 0 - OMD~~~~I__-L~LL~~I~-w

101

102

A

Fig. 1. Time averaging root-mean-square radius of groundstate nuclei. Open circles show the results of QMD andthe full squares indicate experimental results.

C + A CollisonsI

2000 f--

I

I

300 MeVfu

:a

,

-

.§.

g 1000 --o ~~--~I-+--+I--+--4I
I
II--~~
2000 -

83 MeVfu

.

./J/

:a

~

.§.

g 1000 -

o

if

/'

•

/;1 !

-

-0-

!

OMD
Kox etal.

~~--~I~--~
I--~~I--~~

10

20

30

40

50

(A~3 + A¥3)2

Fig. 2. Target-mass dependence of the reaction crosssections of collisions with the carbon beam at theincident energies 300 MeV lu (upper column) and
83 Me V I u (lower col umn). The experimental data aretaken from Ref. 3.

isotope beams. After that we will extend this approachto controle initail distribution and to determine theradii of exotic nuclei.
References
1) J. Aichelin: Phys. Rep. 202 , 233 (1991).
2) K. Niita, S. Chiba, T. Maruyama, T. Maruyama, H.
Takada, T. Fukahori , Y. Nakahara, and A. Iwamoto:Phys. Rev. C 52, 2620 (1995).
3) S. Kox et al. : Phys. Rev. C 35 , 1678 (1987).

31

RIKEN Accel. Prog. Rep. 32 (1999)

Relativistic EOS Table Constrained by Unstable Nuclei for
Supernova and r-Process Simulations
K. Sumiyoshi, H. Shen, K. Oyamatsu, S. Yamada, H. Suzuki, and H. Toki
[Dense matter, Supernova, r-process, Heavy elements]
The physics of supernova is fascinating since it is the
key to understand the stellar evolution and the originof the heavy elements. The mechanism of supernova
explosion is still one of big mysteries in astrophysics.
Whether the r-process nucleosynthesis to create heavy
elements happens in the supernova is also an important question to be answered at the same time. To attack these problems, one has to perform sophisticatednumerical simulations with the reliable information of
nuclear physics at extreme conditions.
One of essential ingradients from nuclear physics isthe equation of state (EOS) of dense matter. The
challenge is to describe both unstable nuclei anddense matter covering the wide region of high density,
neutron-rich and high temperature during supernova
explosion. Because of the lack of the EOS table tocover all conditions, it has been difficult to perform
simulations to follow the series of phenomena: gravitational collapse, core bounce, the birth of a neutronstar, neutrino wind to lead r-process, and explosion.
To provide the properties of unstable nuclei anddense matter in supernova conditions within a reliable nuclear many body framework, we have completed
the EOS table for supernova simulations within therelativistic mean field (RMF) framework. The RMF
framework has been successful to describe the structure of unstable nuclei as well as stable ones. The
effective lagrangian with non-linear (7 and w terms isconstructed based on the relativistic Bruckner HartreeFock theory. The parameters of the lagrangian are
constrained by fitting the experimental data of massand charge radii of stable and unstable nuclei. We apply the same RMF framework to calculations of the
EOS table in the wide region of the environment byadopting the Thomas-Fermi approach. 1 ,2)This relativistic EOS table enables us to performthe full simulations of supernova phenomena from thegravitational core collapse to the cooling of the neutronstar newly formed. We are applying the relativistic
EOS table to the hydro dynamical calculations of corecollapse, the supernova neutrinos from the birth of neutron star, and the neutrino wind from. proto-neutronstar. 3 ) Here we show an example of the application of
the EOS table to hydrodynamical calculations.
Figure 1 shows the calculated trajectory of mass elements in the collapse of the core of a massive star as
a function of time. After the core collapses gravitationally, the bounce occurs at high density, leaving acompact object at center. The shock wave is launched32

10 5 ~~~~~~~~~~~~~~~
0.15
0.16
0.17
0.18
0.19
0.20

Time [sec]Fig. 1. Trajectory of mass elements during gravitationalcore collapse.

at the bounce, and propagates towards the surface,leading to a successful explosion. Although this is atest calculation treating only hydrodynamics without
the neutrino transfer, which is an another key part , wehave found that the EOS table works quite well evenfor dynamical situations. We are currently working on
the full simulations of hydrodynamics with the neutrino transfer to clarify the mechanism of explosion.
We have performed also the numerical simulationsof the neutrino wind from a proto-neutron star bornright after the core bounce. At the surface of the protoneutron star, the matter is heated up due to neutrinos
and escapes as a wind. This wind between the stellar
surface and the shock front is believed to be a site forthe r-process nucleosynthesis. However, the hydrodynamical condition of the wind, such as entropy, electron fraction and dynamical time scale, has a large uncertainty in previous studies. We are now exploring the
dynamics of the wind by hydrodynamical simulations
to determine these conditions and to clarify whether
the r-process occurs and how r-process products are.
References
1) H. Shen, H. Toki, K. Oyamatsu, and K. Sumiyoshi:
Nucl. Phys. A 637, 435 (1998).
2) H. Shen, H. Toki, K. Oyamatsu, and K. Sumiyoshi:
Prog. Theor. Phys. 100, 1013 (1998).
3) K. Sumiyoshi, H. Suzuki, and S. Yamada; in preparation.

RIKEN Accel. Prog. Rep . 32 (1999)

The Long Half-Life of Highly Ionized 44Ti
Y. Mochizuki[Nucleosynthesis, Supernova remnants]ti/~ = 60 ± 1 yrs.
We emphasize here that the laboratory half-life measurements are for the neutral atoms. As mentioned before, 44Ti can be ionized during the evolution of a SNR.
In this case, the resulting "effective" half-life becomes
longer than the experimental value. This is because
44Ti decays 100% by electron capture. The orbitalelectron-capture decay (observed in laboratory) is suppressed, when the nucleus possesses no or a few electrons in astrophysical situation.
In Fig. 1, the calculated results of the effective halflife, using ti/~ = 60 yrs, are shown as a function of
the post-shock electron temperature. In the figure, wehave assumed that the reverse shock hits a layer of
44Ti at 100 yrs after the explosion. The age of Cas A
and the electron density are assumed to be 320 yrs and20 cm -3, respectively. The initial ionization structureof the shocked 44Ti has been taken to be complete
0-, 1-, 2-, 3-electron system, or that under the Collisional Ionization Equilibrium condition. It is clear
from Fig. 1 that the effective half-life becomes longer
because of the retardation of the electron-capture decay.

ne ", 20 Icc
t sh ",100yr

4

g
~

::i

1000

.,!..

Cij

I
Q)

>

t5
1-electron system

Q)

iTI
100

2-

_ _ _ _ _ _ _ _- L_ __ __ _ _ _- L_ _ _ _ _ _~_ __ _ _ _

~

~

33

The half-life of 44Ti measured in laboratory cannot
be applied directly to the astrophysical situation. Thisis because the half-life values measured so far are forneutral atoms. Since 44Ti decays by electron capture
only, the ionization can affect on the decay rate. In thispaper, I discuss the ionization effect on the half-life,
taking into account the evolution of a supernova remnant in which 44Ti was synthesized. A simple model istaken to demonstrate the retardation of the decay as
the first step.
The binding energy of the K-shell electrons of 44Ti iscalculated 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 theejected material decreases rapidly due to the adiabatic
cooling as the ejecta freely expands. Consequently, it isexpected that the created nuclei become neutral within
about 1000 sec.
However, there is a possibility that 44Ti is madeto be ionized again: This is due to a reverse-shockheating. The reverse shock is produced by the highpressure behind the blast-wave shock interacting withthe 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 a supernova remnant (SNR). The reverse shock becomes important, say, from rv 100 yrs
after the explosion.
44Ti is radioactive, and the nuclear ,-rays from its
decay have been detected with COMPTEL in SNR
Cassiopeia-A (Cas-A). The flux detection has a strong
impact, since we can check the theory of collapsedriven supernova explosions through the conversion of
the flux into the initial abundance of 44Ti at the timeof the explosion, using the other observed values of thehalf-life, the distance, and the age of Cas-A.
A hindrance here is the half-life, which is not easy
to be determined experimentally, because the value isof the time scale of human life. For this and for the
astrophysical importance, several measurements of the
44Ti half-life have been done so far. The latest halflife values determined from experiments converge into

10

2

Post-shock Temperature (keV)

Fig. 1. The effective half-life of 44Ti as a function of
post-shocked electron temperature.

33

RIKEN Accel. Prog. Rep. 32 (1999)

The Half-Life of 44Ti and SN 1987 At
Y. Mochizuki, S. Kumagai, * and 1. Tanihata[Nucleosynthesis, Supernovae]
The radioactive nuclei, 56Ni, 57Ni, and 44Ti, are believed to be synthesized in the o:-rich freeze-out process, which occurs in neutrino-driven winds within
about one second after core bounce in supernovae. I)
These nuclei are proton rich, and hence decay bypositron emission or by electron capture. The ,-rayphotons coming out from the decay sequence of 44Ti is
now a strong candidate to explain the late light curveof SN 1987A. In this paper, we discuss the abundanceof 44Ti in relation with its unestablished half-life value
by comparing the theoretical light curves with the observed luminosity of SN 1987A.
It is noted that the production of 44Ti is important to understand the dynamics of core collapse supernova explosions. The 44Ti yield at the time of an
explosion depends strongly on the location of the masscut, electron fraction, and entropy condition in the 0:rich freezeout. Hence, the initial yield of 44Ti provides
unique information to constrain the explosion models.
In the above, the mass cut is the position in a star that
separates the supernova ejecta and the materials whichcollapse into a central compact object, a neutron staror a blackhole.
In Fig. 1, we show the calculated UV-IR light curvesof SN 1987A and the observed luminosities. Our calculation of the light curve is based on Kumagai et al. 2) It
has been established that the observed of light curve ofSN 1987A in early time is first governed by the decay<o7COj""CO>=1.710""<'"n/"Ni>= 1.5

10'"

soo

1000

1500

2000

2500

3000

3500

4000

days after explosion

Fig. 1. The observed luminosities of SN 1987A and thecalculated light curves.
Condensed from the article in Origin of Matter and Evolution of Galaxies, edited by S. Kubono et al. (World Scientific), in press; RIKEN-AF-NP-289 (preprint)
Department of Physics, College of Science and Technology,
Nihon University

34

sequence 56Ni --+ 56 CO --+ 56 Fe, and then by 57Ni --+57 Co--+ 57 Fe. As we can see in Fig. 1, the slowness of the observed decline of the light curve becomes especially distinguished after ",1500 days from the explosion. The
dominant energy source at this time can be attributed
to the 44Ti decay; 44Ti decays by electron capture to
44SC, emitting 67.9 keY (100%) and 78.4 keY (98%)
lines. 44SC then decays mainly by the positron emission into 44Ca, which emits a 1157 keY (100%) line.
The energy release from the 44Ti decay depends
strongly on its half-life. However, the published experimental values for the half-life display a large spread,
ranging from ",35 to ",68 years. In Fig. 1, the halflife of 44Ti is assumed as 60 yrs and as 100 yrs. The
solid lines in the figure denote the calculated evolutionof the total luminosity, corresponding to each value ofthe half-life. Contributions from the decays of 56,57 Co
and 44Ti are also shown, respectively, with the labeled
dotted lines and the dash-dotted lines.
To explain the latest observed luminosity3) which isabbreviated with CTIO + HST in Fig. 1, (44Tij56Ni)= 1.5 has been assumed as for the initial abundance of 44Ti.
Here, (44Tij 56 Ni) is defined as
the ratio of 44Tij56Ni in amounts in the supernova
remnant to 44Caj56Fe in the solar neighborhood,i.e., (44Tij 56 Ni) == [X(44Ti)j X( 56 Ni)] j [X(44Ca)jX( 56 Fe)] o ·We have found that the deduced synthesized mass of
44Ti is consistent with recent nucleosynthesis calculations for the half-life value of 60 yrs, which is the latest
suggested value from experiments, within the uncertainty of the observed luminosity (Fig. 1). It has been
also found that the observed luminosity can be rea- .
sonably explained by the energy release from the 44Ti
decay under the above-mentioned range of the half-lifevalues obtained experimentally so far.
Finally, we note that further observations of the luminosity of SN 1987 A a few years later are greatly
encouraged to reduce the uncertainty that comes fromobservations. It is also noted that the half-life of 44Ti
should be pursued not only for the neutral atom underusual laboratory conditions, but also from the theoretical point of view to study the effect of ionization on
the half-life under possible supernova conditions.
References
1) S. E. Woosley et al.: Astrophys. J. Suppl. 26, 231(1973).
2) S. Kumagai et al.: Astron. Astrophys. 273 , 153 (1993).

3) N. B. Suntzeff: in SN1987A: Ten Years After, edited by
M. M. Phillips and . B. Suntzeff, in press.

RIKEN Accel. Prog . Rep. 32 (1999)

Correlation and Finite Interaction-Range Effects in High Energy
Electron Inclusive Scattering
A. Kohama, K. Yazaki, and R. Seki*[Glauber approximation, Electron inclusive scattering]
We calculate cross sections of high energy electron
inclusive scattering off nuclear matter in a new andconsistent formulation based on the Green's function
method 1) with the Glauber approximation. We suggest the superiority to other formulation 2 ) for a description of this kind of process. Our formulation is anextension of our previous work on the nuclear transparency in (e, e'p) reaction. 3 )Since we are interested in the nucleon quasi-elastic
region, the elementary process is considered to bemostly the eN elastic scattering, e + N --+ e + N. Theenergy loss, w, is roughly 2 [GeV]. We do not intend to
explain the inelastic channel of the eN cross section,
which takes part in the data in high-w region.
The inclusive cross section is written as

dO'eA _ (dO'eN )S(w)dndw dO. el,on,q ,where S(w , q) is the response function. The cross section on the r.h.s. is the on-shell eN elastic scattering cross section, and (... ) implies averaging over spin,i~ospin, and the Fermi motion.
We examine two zero-range approximations for the
N-N potential, which is constructed from the N-N amplitude obtained experimentally. One is the zero-range
approximation in z-direction only (ZRl), and anotheris the zero-range approximation in the whole direction(ZR2). We find out that the ZRl is a good approximation for the finite-range interaction.
The numerical results of the inclusive cross section
are shown in Fig. 1. The incident electron has theene~y, € = 3.595 [GeV], and its scattering angle is() = 30°. The PWIA result directly reflects the momentum distribution of a nucleon in the nuclear matter. Including only the final-state interaction (FSI)
broadens the cross section, but adding the nuclear correlation (ZRl and ZR2) reduces the broadening, thatis, the effect of the FSI.
Although ZRl includes the major part of the finiterange interaction, the cross section of ZRl still overestimates the experimental cross section for low-w region. It seems to contradict our insistence that ourformulation is a consistent treatment of the FSI for
the inclusive process. Furthermore, ZR2 comes closer
to the experimental data than ZRl does, though ZR2
is more approximate expression than ZRl.
Department of Physics and Astronomy, California State
University, Northridge, and W. K. Kellogg Radiation Laboratory, Caltech, USA

10- 2

~
t:l
...

10- 3

~
.0

- - ZRl

2.
3

'tl

10- 4

- - - ZR2c:- .- .-'tl........

No Correlation. PWIA

.,b
'tl

10- 5

0.75

1.25

1.5

Energy Loss", [GeV]

Fig. 1. The cross sections of the inclusive scattering
off nuclear matter. The dotted curve is the case of
PWIA. The dash-dotted curve is the case of only the
FSI (no correlation effect). The solid curve (ZRl) andthe dashed curve (ZR2) are the results of the calculations including both the FSI and the nuclear correlation
with each zero-range approximation. The experimental
data are from Ref. 4.

One reason why this comes about is our use of the
on-shell eN cross section. Since the electron hits abound nucleon, we should use an off-shell eN crosssection, but in principle we cannot determine it by experiments. In order to see the off-shell behavior of thecross section, we should consider it theoretically bymaking a model for the bound nucleon taking accountits internal structure. Since it is beyond the scope of
this work, we just use the on-shell cross section for the
calculations in order to avoid to bring about other ambiguity in our discussion here. Thus, we concentrate on
a consistent treatment of the FSI of the struck nucleon
in the Glauber approximation, and the agreement of
the numerical results with the experimental data is notnecessarily our objective of this work. These facts push
us to study the off-shell cross section, and we leave thestudy in our future work.
References
1) O. Morimatsu and K. Yazaki: Prog. Part. Nuc!. Phys.
33, 679 (1994).
2) H. A. Gersch, L. J. Rodriguez, and P. N. Smith: Phys.
Rev. A 5 , 1547 (1972).
3) A. Kohama, K. Yazaki , and R. Seki: Nuel. Phys. A 551,
687 (1993).
4) D. B. Day et al.: Phys. Rev. C 40, 1011 (1989).

35

RIKEN Accel. Prog. Rep. 32 (1999)

Thansversity Distributions and Spin Asymmetries at RHIC
S. Hino, M. Hirai, S. Kumano, and M. Miyama*[Parton distribution, Structure function]
Transversity distributions, !:::..rq, will be measured
by using the Drell-Yan process at RHIC (Relativistic
Heavy Ion Collider). Major reasons for studying the!:::..rq are following. Because the transversity Q2 evolution is quite different from the longitudinal Q2 evolution, perturbative QCD could be tested by finding thedifference between the transversity and longitudinallypolarized distributions. Furthermore, this difference
could shed light on the relativistic aspect of nucleon
structure in the sense that nonrelativistic quark models predict the same distributions.
First, we have investigated the Q2 evolution equation for the transversity distributions and obtained its
numerical solution. I) Because of the chiral-odd natureof the transversity distributions, the gluon does notparticipate in the Q2 evolution equation. Even thougha distribution is not flavor-nonsinglet, the evolution
equation looks like the "usual" nonsinglet one withouta coupling to the gluon term. Therefore, the results ofQ2 evolution are quite different from the longitudinal
ones. For example, although the identical singlet distributions are assumed at Q2 = 4 Ge y2, the evolvedtransversity distribution, !:::..rqs, at Q2 = 200 Gey2 issignificantly smaller than the longitudinal distribution,!:::..qs, in the region x rv 0.1. The magnitude of !:::..rqs
itself is also smaller than that of !:::..qs at a very smallx( < 0.07) at Q2 = 200 Gey2.
Second, we have studied antiquark flavor asymmetry, !:::"ru/ !:::..rd, by two different descriptions: a mesoncloud model and an exclusion mode1. 2) The p-meson
clouds could contribute to the flavor asymmetry, forexample, because of the d-quark excess in p+. Exclusion effects also affect on the asymmetry because of thedifference in polarized quark probabilities in the SU(6)quark model. Although these mechanisms are muchdifferent, it is interesting to find that both models predict !:::..r d excess over !:::..r u. Next, the obtained flavorasymmetric distributions are used for calculating thetransverse double spin asymmetry, A rr . In comparison with the flavor symmetric double spin asymmetry,significant deviation was found in the proton-proton*1

36

Department of Physics, Saga University, http://www2.
cc.saga-u.ac.jp/saga-u/riko/physics/quantuml/structure.
html.

(pp) reaction. However, the single process is not sufficient for investigating the flavor asymmetry. We
therefore proposed that the flavor asymmetry can bemeasured by using the polarized proton-deuteron (pd)Drell-Yan process in combination with the polarized
pp reaction.
Because the Drell-Yan formalism with the spin-1
deuteron had not been available, we have investigated
the general formalism of the Drell-Yan processes with
spin-1/2 and spin-1 hadrons. 3 ) Imposing Hermiticity,
parity conservation, and time-reversal invariance, we
found that 108 structure functions exist in the DrellYan processes. The number reduces to 22 after integrating over the virtual-photon transverse momentum, QT, or after taking the limit QT -+ O. It wasalso shown that fifteen spin asymmetries can be investigated. Because the deuteron is a spin-one hadron,
there are additional structure functions to those of the
proton. In particular, it is interesting to measure thequadrupole spin asymmetry, A uQo ' which is related tothe tensor polarized distributions, bq. The Jq should
be interesting quantities because the tensor structure isnot clarified within the parton model. If the deuteronacceleration is realized at RHIC in the future, The Jq
can be measured. The polarized hadron reactions havean important advantage over the lepton reactions inmeasuring the antiquark tensor polarization. 3 ) Because
the essential pd formalism is now completed, it is possible to study the !:::"ru/ !:::..rd by measuring the Arr andthen by taking the difference between the polarized pp
and pd cross sections.
References
1) S. Kumano and M. Miyama: Phys. Rev. D 56, 2504
(1997); M. Hirai, S. Kumano, and M. Miyama: Comput.
Phys. Commun. 108, 38 (1998); 111, 150 (1998).
2) S. Kumano: Phys. Rep . 303, 183 (1998); S. Kumano
and M. Miyama: research in progress.
3) S. Hino and S. Kumano: preprints SAGA-HE-136-98,
SAGA-HE-139-98.

RIKEN Accel. Prog. Rep. 32 (1999)

A New Parametrization of Polarized Parton Distributionsin the Nucleon
Y. Goto, N. Hayashi, M. Hirai, H. Horikawa, S. Kumano, M. Miyama, T. Morii,
N. Saito, T. Shibata, E. Taniguchi, and T. Yamanishi[Polarized partons, NLO analysis, Nucleon spin structure]
To study how the partons polarize in the nucleon is
crucially important to understand the spin structureof the nucleon. Recently there has been a renewed interest on polarized parton distributions in the nucleon,
largely stimulated by acquisition of the high-precision
polarized data on various targets 1 ) and by developmentof the next-to leading order (NLO) QCD calculationsof polarized parton distribution functions. 2)
In this work, introducing reasonable physical conditions, i.e., the positivity condition and the counting rule for the helicity-dependent parton distributionfunctions, we propose a new parametrization 3 ) of thepolarized parton distribution with initial scale Q5,

analysis is absolutely necessary to extract informationon the polarized parton distribution. We have also
compared our results of x~dv(x) and ~dv(x)/dv(x)with the Spin-Muon-Collaboration(SMC) data7 ) at
Q2 = 10 GeV2 as shown in Fig. 1.

(a)

0.001

0.01

0.1

0.2 , - - - - - - -- - - -- - - - - - - - ,x'>-0 -0.2 I - - - -- - - - - - ' - - - - - -f-t-- - t - - ' - - + - - + - - - - - l<JX-0.4 1--- - -- - - - - - - - - + - - - - 1~fi(X, Q6) = Ai XQi (1 + ri X'xi) h(x, Q6) .

(1)-0.6 '------_ _ __ _ _ _ _ _ _ __ _----1

Here, i = uv(valence u quark), dv(valence d quark),q(sea quark) and g(gluon); ~fi(X, Q5) and ii(X, Q5)
are the polarized and unpolarized distribution functions, respectively; and Qi, ri and .Ai are the free parameters; and Ai is a normarization factor. The counting rule naturally leads to the condition for polarized
distribution functions 4 )

(2)

x

(b)

0.001

0.1

0.Q1

1.0

X

'>
~

0.5
0.0

x'> -0.5

r----.....!

where it (ii-) represents the distribution function of
the parton helicity parallel(anti-parallel) to the nucleon helicity. This condition, together with a reasonable assumption that the first moment of each polarized parton distribution should not become infinite
at Q5, constrains the parameters in Eq. (1) as Ai =1:'"Yi' Qi ~ 0, ri i- -1, .Ai > -Qi . Further constraints are given for the valence quark distributions:
From the weak decay constants, F and D, obtained
from the ,a-decays of neutron and hyperons, we candetermine the first moment of the polarized valence u
and d quark distributions by assuming the SU(3) flavor
symmetry, thus constraining the free parameters for~uv and ~dv. Then, we have finally 10 remaining parameters, Qu v , ru v , Qd v ' rd v ' Q~, rq, .A q , Qg, rg, .A g , which
can be determined by the X - analysis of the experimental data of a virtual photon asymmetry, A 1(x, Q2),
for the proton, neutron, and deuteron targets.
Using the Gliick-Reya-Vogt(GRV) parametrization
for unpolarized parton distribution functions 5 ) and using the R19906) for the value of R which is the ratio of
the longitudinal to transversal virtual-photon nucleon
cross sections, we have carried out the x2-analysis tothe data. The obtained parameters can reproduce wellthe experimental data. The results of x2-analysis aresubstantially better for the NLO(X2 / d.o.f = 0.897)
than for the LO(X2/d.o.f = 1.088). Thus, the NLO

hJt I ~ ';'-J-0<J -1.0t-1.5

xFig. 1. Calculated distributions of (a) xfldv(x) and (b)fld v (x) / d v (x) at Q2 = lOGe V 2 . Data shown by closed
circles are from Ref. 7.

Our parametrization looks promising. We have proposed an input polarized distribution by introducing
physical conditions of positivity and counting rule, andobtained better results than other works done so far.
References
1) D. Adams et al.: CERN-EP/98-85 (1998); B. Adeva etal.: Phys. Lett. B 412, 414 (1997); K. Abe et al.: SLACPUB-7753 (1998); A. Airapetian et al.: hep-ex/9807015(1998) .
2) R. Mertig and W. L. van Neerven: Z. Phys. C 70, 637(1996); W. Vogelsang: Phys. Rev. D 54, 2023 (1996).
3) Y. Goto et al.: in preparation.
4) S. J. Brodsky, M. Burkardt, and 1. Schmidt: Nucl. Phys.
B 441, 197 (1995).
5) M. Gliick, E. Reya, and A. Vogt: Z. Phys. C 67, 433(1995).
6) L. W. Whitlow et al.: Phys. Lett. B 250, 193 (1990).
7) B. Adeva et al.: Phys. Lett. B 420, 180 (1998).
37

RIKEN Accel. Prog. Rep. 32 (1999)

Semi-Classical Sine-Gordon Solitons on a Finite Interval
T. Matsuki[Topological soliton, 1+1 D, Sine-Gordon model]
Recently, a non-perturbative method based on treating the system on a light-like finite interval has attracted much attention. A vast number of theories have been treated, starting from the 1+1 dimensional(D) Yukawa model,!) upto QCD 1 + 1 . 2)
The Sine-Gordon model has also been studied in
the soliton charge Q = 0 sector,3) from which one
observes the soliton-antisoliton threshold, but cannot
derive the conclusive evidence of existence of the onesoliton state. If the method is truly non-perturbative,
it must be capable of incorporating the nonperturbative states, the solitons, which arise in theories with
topology or spontaneous symmetry breakdown (SSB).
One of the problems of the formalism is that we areworking on a finite interval. Care must be taken due tothe boundary conditions(B. C.) which are clearly different from the infinite interval problem. In order toinvestigate this problem, we concentrate on a semiclassical description in the equal time formulation , andsee if one can deduce the quantum mass of the one soliton state. The linearized eigenfunction can be utilized
for the light-front formulation.
We first construct the one soliton classical solution
in the Sine-Gordon model. The Lagrangian is given by

J.l2£, = ojL¢ojL¢ - {32 (1 - cos({3¢)).

The static solution is given by solving the Lagrangian £, = _¢'(X)2 - V(¢(x)) under the boundary condition that is periodic modulo 27r / {3, which isa B. C. that conserves momentum. This can be interpreted as the single particle mechanics with the Hamiltonian H = i;2 - V (x), if we do the replacements x --+ tand ¢ --+ x. Let the energy of the particle be given by
H = E. Then, the finite interval problem corresponds
to E > O. Solving
1
J.l2
ri;2 - {32 (1 - cos(x)) = E ,calculate the classical mass of the soliton:
M = J[~¢'2 + V(¢)]

2 2J.l 2= {32 y[2E(k) - (1 - k )K(k)]= ~[1 + 4e- 2jLL + O(e- 6J-LL)](L --+ (0)
7r

38

2

1 4

(1)

[-O~ + J.l2{2Sn2(-Ix , k) -1}]?J;n = w~,?J;n.
Replacing x by u = -(J.l/k)x, we have[o~ + {h n - 2k 2Sn(u, k)2}]?J;n = 0,

where h n = k 2 (1 + ~). This equation is known as the
J-L
Lame equation of order one.
The eigenfunction for L ,. . . , 0 can also be obtainedby perturbing with the parameter k. For example inthe case of the even Lame function Ec( u), expand it as?J;(v) = Ao + I: n A2n cos(2nv) where sin v == Sn(u, k) .
The Lame equation then becomes equivalant to thefollowing recursion relation 4 ,5)

1/2[(2 - 2n)(2n + 3)k2]A2n+2+[2(h - k 2 ) - 4n 2(2 - k2)]A2n+1/2[2n( - 2n + 3)k 2jA 2n _ 2 = 0
Perturbing with small k 2 , i.e. with small L, it gives
Wn

Here, k = V/2T
E+'2~2" and Sn(u, k) denotes the Jabobianform of the elliptic function. In order to determinek, we look at the boundary condition 1f2L = 2K(k) ,where K (k) is the first complete elliptic integral. Solving this equation for k, we have k = k(L).
Now that we have the classical solution, we can1[where E(k) is the complete elliptic integral of the second kind, and ~ = (J.l/7r)L. Notice that it gives thecorrect limit at L --+ 00, and that the expression diverges as L --+ 0
We may discuss the semi-classical nature of the soliton by expanding the field around the classical solution. The linearized equation of motion of the fluctuation becomes

and with the original notation, we obtain

2-1 (Sn(-k[x-xo],k).
J.l)¢(x)=-gcos

2= {32 L 1 + 2~ - 2~ + .. ], (L --+ 0),= "; (1 + 4n21_ 1

e + ...) ,where ~ = (J.l/7r)L. We can treat the odd Lame function in a similar way.
The eigenvalues allows us to calculate the quantum
mass correction for L ,. . . , O. Taking care of the vacuum
energy and the boson mass renormalization,6)1

7r ( -2~
1 2 + [12ln 2 - 24
13 + 8((3)
1~M = L~ 4 + .... )we can finally obtain a finite result. Notice that thedependence of 6.M on L differs significantly from thatof the classical mass given by Eq. (1). It is impossible, unlike the infinite interval case, to include thequantum effect by redefining the coupling constant as{32 -+ {32 / (1 - (32 / 87r), at least not in a L- independent
fashion.
To summarize, we have obtained the classical onesoliton solution on a finite interval. We have obtained
the dependence of the classical soliton mass on theinterval length. The classical solution is at the sametime the solution on the light-front. Moreover, we have
performed the semi-classical quantization of the soliton, by taking into account the fluctuation around theclassical solution. Thus we have shown that the semiclassical treatment is indeed possible on a finite interval. It is uncertain , however, whether the system still
maintains its semi-classical exactness.
References
1) H-C. Pauli et al: Phys. Rev. D 32, 1993 (1985).
2) K. Hornbostel et al: Phys. Rev. D 41, 3814 (1990).
3) M. Burkardt: Phys. Rev. D 47, 4628 (1993).
4) E. L. Ince: Proc. Royal Soc. Edinburgh 60 , 47 (1940).
5) E . L. Ince: Proc. Royal Soc. Edinburgh 60 , 83 (1940).
6) Kikkawa and Sakita: in Quantum Mechanics of Many
Body Systems by Path Integral (Iwanami Publ., 1986),
p. 181 (in Japanese).

39

RIKEN Accel. Prog. Rep. 32 (1999)

Muon Catalyzed Fusion and Muon to 3He Transfer in Solid T2
Studied by X-ray and Neutron Detections
T. Matsuzaki, K. Nagamine, K. Ishida, S. N. Nakamura, N. Kawamura, M. Tanase, M. Kato,
K . Kurosawa, M. Hashimoto, H. Sugai, K. Kudo,*1 N. Takeda,*1 and G. H. Eaton*2[Muon catalyzed fusion, Exotic atom, Muonic X-ray, t-t fusion neutron]
After a series of muon catalyzed fusion experimentswith a liquid/solid D-T mixture at RIKEN-RAL Muon
Facility by detecting the X-ray and neutrons originatedfrom the d-t fusion process,I) we have conducted a similar measurement of muon catalyzed t-t fusion and of
the related phenomena with a solid T2 target. This
experiment is important not only for the back-up to
analyze the data of muon catalyzed d-t fusion, but also
for a study of the new type of physics related to thet-t fusion.
The experiment has been conducted at RIKEN-RAL
Muon Facility by using the same set-up already installed for the d-t muon catalyzed fusion experiment. 1)
The T2 gas target (T: 99.1% and H: 0.9%, 56 TBq:
1500 Ci) prepared at JAERI was installed to the tritium gas handling system 2) which can purify the target
gas at the site of experiment by removing 3He impurity
just before the measurement.
The muon catalyzed t-t fusion reactions in the solid
T 2 target are expressed as following,t + t + j.L- ---t a + 2n + j.L- + Q(I1.33 MeV)

(1)---t (j.L- a) + 2n + Q.

(2)

Regarding the reaction (2) as the muon-to-a sticking process, we have directly deduced the X-ray yield
related to the sticking probability (w s ) by observing
Ko: X-ray from the (j.L-a) atom, where the Doppler
width of observed Ko: X-ray line has also given us an
information on the motion of (j.L - a) atom in solid T 2
medium. The observed X-ray spectrum is shown in
Fig. 1. We have also deduced the (ttj.L) molecule formation rate, A(ttj.L) , and effective sticking probability,
W s (ttj.L), for the t-t muon catalyzed fusion process by
combining the X-ray and neutron data.
It is known in a series of our experiments that 3He,a decay product of tritium, is accumulated in the solid
T2 target, and muon does transfer from (tj.L - ) to 3He
through the (t 3 Hej.L-) molecule formation while emitting the characteristic 6.7 ke V photons. As shown in
Fig. 1, we have observed the photons to deduce themolecule formation rate A( t 3 Hej.L -) and radiative decay branching ratio of the (t 3 Hej.L -) molecule.
A strange 3He accumulation effect in solid T2 wasobserved in the time dependence of t-t fusion neutron
disappearance rate, An , after solidification, as shownin Fig. 2. The An, determined by the time spectrumof t-t fusion neutron, increases linearly (as shown by

II§
0

u.....

t'He#

4000

toGO

2000

1000

10

12

14

EnergY[bV)Fig. 1. Observed X-ray spectrum for p,- in solid T2 target
in the time domain from 80 to 2080 nsec after p, - pulse.
The clear peaks at 6.7, 8 .2 and 9.7 keY are assigned asradiative-decay photon from the (t 3Hep,) molecule, andthe KQ and K.a X-rays from the (p,- a) atom.

~fI) z.t

E:u 1---+--- +-+~u~~~-~~~tM-~~
AI
fl 2

8

1.1

~u

~-'-+---""";-l---+---++-'-AI-4,!I4"1~ I.' ~4-l'--l-t--+Ht-H-+--~~ 1,2 __-"-+----+--+-----i'---t-+- ......,~

;a
§ '.

~OAI__~---+-+_-+-~~

::s

~

0

Time20after ~olidificati~n [hiFig. 2. Time dependent fusion-neutron disappearance
rate, .An, in T 2 as a function of the time after the solidification which can be considered as the time after
the 3He removal. As a reference, the same data for the
DO.3To.7 mixture is shown.

filled circles) with time in the beginning, and then depicts a leveling-off behavior at around 20 h, followed
by a gradual decrease until 60 h. The strange turnover of An at around 20 h should be compared withthe similar phenomena in the DO .3TO.7 data (shown by
open circles) at 30 h. This phenomenon can probably be explained by a 3He bubble formation througha rapid diffusion of 3He in solid T2 or D-T mixture
to find out another 3He. The critical 3He concentration of around 125 ppm in both cases seems to be an
important parameter for the phenomenon.
References

*1

*2

40

Electrotechnical Laboratory (ETL)
Rutherford Appleton Laboratory (RAL), UK

1) K . Ishida et al: RIKEN Accel. Prog. Rep. 31, 49 (1998).
2) T. Matsuzaki et al: RIKEN Accel. Prog. Rep. 30, 151(1997).

RIKEN Accel. Prog. Rep . 32 (1999)

Measurements of 3He Accumulation Effect on Muon Catalyzed
Fusion in the Solid/Liquid D-T Mixtures t
N. Kawamura, K. Nagamine, T. Matsuzaki, K. Ishida, S. N. Nakamura, Y. Matsuda, S. Sakamoto,
M. Tanase, M. Kato , K. Kurosawa, H. Sugai, K. Kudo,*1 N. Takeda, *1 and C. H. Eaton*2[Muon catalyzed fusion, Fusion produced neutron]
Through the D-T muon catalyzed fusion (J-LCF)
experiments carried out at the RIKEN-RAL Muon
Facility,1) we found the 3He accumulation phenomenon: the 3He originating from tritium (3 decay
was trapped in the solid D-T system, while that inliquid was diffused and evaporated into the D-T gas.
In the present work, the D-T target was initiallypurified by the tritium gas handling system,2) for the
3He concentration to be reduced to < 1 ppm. Afterwards, 3He concentration increases by the rate of
1.55 x 10- 4 x C t per day, where C t is the original tritium concentration.
Figure 1 shows typical timing spectra of fusion neutrons. Clear difference is seen between solid and liquid,i.e. the neutron disappearance rate An increases withtime in solid, while no visible change was observed inliquid. Further analysis gives us the following featureof this phenomenon: (1) only in solid, the neutron disappearance rate increased with the time after condensation; (2) by melting solid, the neutron disappearance
rate returns to the original value measured at the timeright after solidification.
Solid

Liquidinating from tritium {3-decay, C Hc , changes with timein a unit of hour, and a muon trapped by such a 3He
is lost out of the JICF cycle, and W increases. Thus
increase of An is explained by the 3He accumulation
effect. By using the muon transfer rate from (dJ-L) and(tJI) to 3He, AdHeIL and AtHeIL' and the capture rate to
3He from free muon, Aa , the increase of An defined as
AHc (= An(T) - An(T = 0)) is dissolved as:

AHe = ¢ (fdILAdHeIL + ftILAtHeIL + faAa) CHe(T),where, fx is the ratio of muon residing time in thestate x (= dJ-L, tJI, a(free)). During the typical experimental periods of 4- 5 days, CHe = AtTCt is a good
approximation, in which At is the tritium decay rate.
In Fig. 2, AHe is plotted with various C t as a functionof the time after solidification and after liquefaction, T.
The tendency shown in this figure is consistent withthe model supposing the 3He accumulation. Namely,
An increases linearly in each C t , and the slope of the
T-AHe plot increases with C t only in solid.
According to our further analysis,2) fdIL' ftIL and
fa were determined, and we obtained the result of
AdHeIL = (6 ± 2) x 108 S-1 and AtHeIL = (4.2 ± 0.3)
x 109 S-1, which is consistent with the theoreticalprediction. 3)(a) Solid(b) Liquid

Fig. 1. Typical time spectra of fusion neutrons of jLCF
in D-T mixture: solid and liquid with Ct = 0.7 at (a)T = 0-10 h, (b) 10-20 h and (c) 20- 30 h after condensation.
The An is dissolved into two parts as An = Ao +W ¢Ac, where Ao is the muon decay rate , W is thetotal muon loss probability per cycle, ¢ is the D-T target density normalized by the liquid hydrogen density,
and Ac is the muon cycling rate in dt- JICF. In the intended system, only the concentration of the 3He orig-*1*2

Condensed from the article in Hyperfine Interact. 118/119(1999), in press .
Electrotechnical Laboratory (ETL)
Rutherford Appleton Laboratory (RAL), UK

Fig. 2. The plot of AH e in (a) solid and (b) liquid withvarious Ct.

References
1) K. Nagamine et al. : Hyperfine Interact. , 118/119(1999) , in press.
2) K. Ishida et al.: Hyperfine Interact., 118/119 (1999),
in press.
3) A. V. Kravtsov et al.: J. Phys. B 19, 2579 (1986).

41

RIKEN Accel. Prog. Rep. 32 (1999)

Muon to Alpha Sticking K,a/K a X-ray Ratio in Muon Catalyzed
D-T Fusion at the RIKEN-RAL Muon Facilityt
S. N. Nakamura, K. Nagamine, T. Matsuzaki, K. Ishida, N. Kawamura, Y . Matsuda,
S. Sakamoto, M. Iwasaki, M. Tanase, M. Kato, K. Kurosawa, H. Sugai,
K. Kudo,*1 N. Takeda,*1 and G. H. Eaton*2[Muon catalyzed fusion, Exotic atom, Muonic X-rays]
The negative muon (/-L-) to a initial sticking probability (w~) calculated with nuclear reaction theory cannot be compared directly with the experimentally observable effective sticking probability (ws).
In order to associate these two quantities, detailed
knowledge about atomic processes of the /-L - a atom
is essential. In reality, the value of experimentally observed Ws is smaller than that of theoretically predicted
one. 1) However, it was difficult to identify which causes
the discrepancy, w~ calculation or atomic process calculations.
Study of the intensity ratio between K.e and Ka Xrays from /-L- a atom can contribute much to answer
the above question; because such a ratio is nearly independent of the initial sticking process, but is very
sensitive to the atomic process. However, the observation of K.e X-ray had been impossible thus far due toa large bremsstrahlung background from the tritium
j3 decay. Measurement of the X-rays and neutrons
from muon catalyzed d-t fusion was carried out at the
RIKEN-RAL Muon Facility.I) The world highest intensity pulsed muon beam has enabled us to observe
K.e X-ray for the first time.
Experiments to measure the K.e /K a intensity ratio
were performed for D- T mixtures with different tritium
concentrations.
The area of K.e and Ka X-ray signals in the energy
spectrum was obtained for each tritium concentration,and it was corrected for a difference of attenuationby the materials between D- T target and Si(Li) Xray detector. Figure 1 shows the result. The averaged
K.e/Ka intensity ratios for liquid and solid were 7.5 ±
1.0% and 6.0 ± 1.2% (the errors are purely statistical), respectively. The preliminary experimental result
tends to give smaller K.e /Ka intensity ratio than thetheoretical values, though the K.e / Ka ratio is sensitive

•1

*2
42

Condensed from the article in Hyperfine Interact. 118/119(1999), in press .
Electrotechinical Laboratory (ETL)
Rutherford Appleton Laboratory (RAL), UK

Kp / Ka Intensity Ratio
15.0

Markushin 3 )

12.5

g

Cohen 2 )Cohen 4 )10.0

01---+--..!#---"*--+---;r~----1I--j Cohen 4) w / Full Stark

....,
(\j

0::

Upperlimit (C, =0 .04";)
by H.Bo.sy el al O )(PSI) 95";C .L.

7 .5

tI

~

"'-..

...

5.0

~

2.5

o

Liquid•Solido.0 '--'-....J...J.J'--'---'--'--'-..L-J.--'----'--'--'-.L.-L--'--'---'--~
o
W
~
~
~

Tritium Concentration, Ct (%)

Fig. 1. The K/3/Ka X-ray intensity ratio. Open circles are
liquid data points and closed ones solid. Solid lines aretheoretical predictions and dashes line is an upper-limit
obtained by the previous experiment. The larger points
show our averaged results.

to the way of background subtraction.
In order to obtain more reliable data, a high precision experiment for the K.e/Ka X-ray intensity ratio isin progress at the RIKEN-RAL Muon Facility.
References
1) K. Nagamine et a1.: Contribution to EXAT98, Hyperfine Interact., in press; T. Matsuzaki et a1.: Contribution to EXAT98, Hyperfine Interact., in press; K. Ishida
et a1.: Contribution to EXAT98, Hyperfine Interact., inpress; N. Kawamura et a1.: Contribution to EXAT98,
Hyperfine Interact., 118/119 (1999), in press.
2) J. S. Cohen: Muon Cata1. Fusion 3, 421 (1988).
3) V. E. Markushin: Muon Cata1. Fusion 3, 395 (1988).
4) J. S. Cohen: private communication (1998).
5) H. Bossy et a1.: Phys. Rev. Lett. 55, 1870 (1987).

RIKEN Accel. Prog. Rep. 32 (1999)

X-ray and Neutron Measurement of a-Sticking Probability
in Muon Catalyzed dt Fusion at the RIKEN-RAL
Muon Facility
K. Ishida, K. Nagamine, T. Matsuzaki, S. N. Nakamura, N. Kawamura, S. Sakamoto, Y. Matsuda,
M. Tanase, M. Kato, K. Kurosawa, H. Sugai, K. Kudo,*l N. Takeda,*l and G. H. Eaton*2[Muon catalyzed fusion, Muonic X-ray]
The muon to alpha sticking probability (w s ) is themain component of muon loss in muon catalyzed fusion (J.LCF) and thus determines the maximum numberof fusions catalyzed per muon. However, the measurements so far, mainly by fusion neutron detection, havealways shown smaller value of Ws than that by theoretical calculations and this has been the most significant
puzzle in J.LCF. To solve this problem, we started measurement of X rays from the (aJ.L)+ ion, which is adirect product of the sticking.
Measurements were made for liquid and solid
D 1 - x Tx mixtures with x = 0.1, 0.2, 0.28, 0.4, 0.5,
0.6 and 0.7.1) With the use of the world strongest
pulsed muon beam at the RIKEN-RAL Muon Facility,
a clear Doppler broadened X-ray peak was sucsessfully
observed 2 ) above the bremstrahlung background fromtirtium .a-decay.
The effective sticking probability Ws was determinedby subtracting the ddJ.L and ttJ.L side channel contributions from the muon loss probability W obtainedby neutron detection. The obtained value of Ws wasconsistent with the measurements done at PSI and
LAMPF and the discrepancy between experiments andtheories was again confirmed.
'
The Ko: X-ray yield per dt-fusion Y(Ko:), as shown in
Fig. 1, was determined by dividing the X-ray yield by
the number of fusion neutron (Yx/Yn ) and subtracting
contributions due to dd/1 and ttJ.L side channel (Ydd and

ytd:
0.4 -

1

0.3 -

Liquid 1

y~~~~:Q

I. 1_

Y.~~t~--Y(K,,)
Q

0.2/rPSI

-

01

1

1

1

1

0 :4 -

1

Solid

I

I

O.3~_~_••Y(K.)-~2 --O. 1 L-<-.'-'-'-.L..-.o.:-1"-'--'-.l........o-I-,-,--,-.L..L.
1...........-,---,-1-,-,---,-,---,
0.0

0.2

0.4

0.6

0.8

1.0

Tritium Fraction (C t )Fig. 1. The Ka X-ray yield per fusion. The filled squares
are the measured number of X-rays per fusion neutron. The open squares are the values with ddJ-t andttJ-t-contributions (Ydd and Yit) subtracted.
*1*2Electrotechnical Laboratory (ETL)
Rutherford Appleton Laboratory (RAL), UK

The obtained values of Ws and Y(Ko:) are plottedin Fig. 2 and are compared with theories. The theoretical values were calculated by combining the initial
sticking probability calculation (w~ = 0.912%)3) andthe atomic process calculations4 - 6 ) (R: regeneration
probability, ,Ka : X-ray yield per initial sticking). The
measured Y (K 0:) was smaller than most of the theoretical calculations, but the deviation was not as significant as the case for the effective sticking Ws' Thissuggests that there might be some unknown factor in
aJ.L atomic process that makes the regeneration probability R larger than expected.
Thi s expo Theory(¢ = 1.2)
O Cohen(88)• Solid
Liquid L:, Markushin~Cohen(98)

+

0.30

o

3'"

:!l

i"-

II

0.25

a
;:,::
>:' 0.20
o. 15

L-..L.""'"-"--'--'-"'--'---'--'----'--'--'--'~___"_'---'-~'--....l

0.3

0.4

0.5

0.6

0 .7

Effective Sticking c.J. :0 c.J. DO- R )Fig. 2. Comparison of our measurement and calculations 4 - 6 ) of effective muon sticking probability Ws andthe sticking J-to: X-ray yield Y(Ka).
This X-ray result, in combination with additional ,finding for the K,a/Ko: intensity ratio,7) will be used tosolve the puzzle of muon to alpha sticking.
References
1) K. Ishida et al.: Proc. of Monte Vertia Workshop
on Exotic Atoms, Molecules and Muon Catalyzed Fusion (EXAT98), Ascona (1998); Hyperfine Interact.
118/119 (1999), in press.
2) K. Ishida et al.: RIKEN Accel. Prog. Rep. 30, 39(1997); K. Ishida et al.: RIKEN Accel. Prog. Rep. 31,
49 (1998).
3) Chi-Yu Hu, G. M. Hale, and J. S. Cohen: Phys. Rev. A
49, 4481 (1994).
4) M. Struensee and J. S. Cohen: Phys. Rev. A 38, 44(1988).
5) V. E. Markushin: Muon Catal. Fusion 3, 395 (1988).
6) J. S. Cohen: RIKEN Rev. No. 20, p. 8 (1999).
7) S. N. Nakamura et al.: RIKEN Accel. Prog. Rep. 32,
42 (1999).

43

RIKEN Accel. Prog. Rep. 32 (1999)

RHIC Spin Project
Y. Batygin, H. En'yo, Y. Goto, N. Hayashi, T. Ichihara, K. Imai, M. Ishihara, T. Katayama, T. Kawaguchi ,K. Kurita, Y. Kondo, Y. Mao, A. Masaike, R. Muramatsu, J. Murata, Y. Nakada, M. Nakamura,
H. Okamura, M. Okamura, N. Saito, H. Sakai, Y. Sakemi, T. Sakuma, H. Sato, H. Sato,
T-A. Shibata, H. Takahashi, A. Taketani, E. Taniguchi, J. Tojo, T. Tominaka, H. Torii,
T. Wakasa, Y. Watanabe, H. Wu, M. Xiao, K. Yamamoto, and M. Yosoi[ pp interaction, Structure function, Spin, Asymmetry, Polarized beam]
RHIC Spin project is the integrated efforts of accelerator, experimental, and theoretical physics to study
the polarization phenomena in high energy hadron reactions using polarized proton beams at RHIC. This isa report of the forth year of this project.
For the accelerator part, a major progress was thecompletion of the design of the RHIC as a polarized
collider, which is now summarized in design manual. 1)
The polarized ion source from KEK has been modified
at TRIUMF to strengthen its current by a factor of
10 or more. In addition, the beam transport from theion source to RFQ is being designed to minimize depolarization of the proton beam. Furthermore, the firstfull-length helical dipole magnet is being fabricated at
BNL, and the field analysis method has been developed
using three dimensional model calculations.
The polarization of the beam will be measured withtwo methods in the RHIC polarized-beam commissioning. One is to utilize the asymmetry AN for inclusive
pion production at large-xF (pion polarimeter). Another is to use the theory prediction on AN for elastic
scattering of the proton on carbon in Coulomb-nuclearinterference (CNI) region: CNI Polarimeter. The ideaof pfon polarimeter has been verified using a 22 Ge V / cpolarized proton beam extracted from AGS in the experiment E925. 2 ) The CNI polarimeter will be installedin AGS at BNL soon for the test as the experiment
E950. We have finalized the detector setup based on
the test experiments at Kyoto University and .Indiana
University Cyclotron Facility.3)
The magnet for PHENIX Muon Arm has been fabricated at MELCO, Japan, and assembled at BNL(Fig. 1). It was successfully excited up to the full field,
and the field will be mapped precisely soon.
A major progress on the detector construction has
been marked by the completion of the installation ofmuon identifier (MuID). The MuID panels are fabricated in a Japanese factory and in BNL. The detailsof the fabrication are described in Refs. 4 and 5.
We have exposed the PHENIX electromagnetic
calorimeter to high-energy beams (6.0 to 80 GeV) at
CERN to investigate the performance at high energy.
Its linearity, shower profile, and hadron response havebeen studied. The analysis is still going on, and thepreliminary results are presented in Ref. 6.
A computing center for the PHENIX data analysis
and simulation in Japan is proposed. We have finalized
its conceptual design 7) and it has been reviewed by the
RHIC Computing Facility review committee. A prototype of the CPU farm and file server system has been
44

Fig. 1. Recent photograph of PHENIX detector system.
successfully built at BNL. Most of the PHENIX standard software has been installed, and they are runningon the CPU farm for the evaluation of the prototype.
In addition to the previous simulation works on
prompt photon and W productions, we have extended
our studies to include the J /'I/J production, whichshould be sensitive to the gluon polarization Llg( x)in the proton. ALL has been evaluated8 ) using models
on Llg(x). This study will be extended to determine
the production mechanism of J / 'I/J and to evaluate thesensitivity to Llg(x).
We have formed a working group on polarized parton distribution with theorists to perform a global fitof existing experimental data to the formulae in both
leading order and next-to-Ieading order in perturbative
QCD. Preliminary results are discussed in Ref. 9.
References
1) Design Manual of Polarized Proton Collider at RHIC,
July 1998.
2) N. Hayashi et al.: RIKEN Accel. Prog. Rep. 32, 46(1999).
3) J. Tojo et al.: RIKEN Accel. Prog. Rep. 32 , 52 (1999).
4) A. Taketani et al.: RIKEN Accel. Prog. Rep. 32, 50(1999).

5) K. Kurita et al.: RIKEN Accel. Prog. Rep. 32, 48(1999).

6) Y. Goto et al.: RIKEN Accel. Prog. Rep. 32,47 (1999).
7) Y. Watanabe et al.: RIKEN Accel. Prog. Rep. 32, 53(1999).
8) T. Sakuma et al.: RIKEN Accel. Prog. Rep. 32, 45(1999).
9) Y. Goto et al.: RIKEN Accel. Prog. Rep. 32, 37 (1999) .

RIKEN Accel. Prog. Rep. 32 (1999)

Simulation of the J /1/J Production in Polarized
Proton-Proton Collision
T. Sakuma, Y. Goto, K. Kurita, N. Hayashi, N. Saito, and T-A. Shibata[RHIC , Spin, Asymmetry, Jj'I/J, Color-octet, MuID]
We have studied the J /'I/J production in polarized
proton-proton pp collision for the RHIC-Spin l ) in order to probe the gluon inside the polarized proton. Although the J /'l/J production is sensitive to the gluon distribution function, the production mechanism has not
yet known completely. There is Color-Octet Model 2 )(COM) that is considered as the most powerful modeland is successful in explaining the direct J/ 'I/J cross section at the CDF which is one of pp collider experiment.
We performed the J /'I/J Monte Carlo simulation withmodified PYTHIA3) event generator in which COM
was implemented. 4 ) We considered the gg -+ gJ /'I/J
subprocess only as the first step.
We generated direct J / 'I/J events in pj5 collision at.jS = 1.8 Te V and extracted color-octet matrix elements(0Io;/1/J(3SdI0) = 4.0 x 10- 3(OIO;/1/JeSo)lo) + ~2 (OIO;/1/Je Po)IO) = 6.1 X 10- 3c5from CDF data. ) Using this matrix elements, we predicted the direct J / 'I/J cross section and spin asymmetry
in pp collision at RHIC energies (.jS = 200,500 GeV).
Expected direct J / 'I/J cross sections are shown in
Fig. 1. All points were multiplied by the muon branching fraction B(Jj'I/J -+ J-L+ J-L-) = 0.0601. PHENIX
Muon Arms acceptance cut (1.2 ~ IrJl ~ 2.4) was also
applied.
10
I

..-

I

yield of an unpolarized event was weighted by~G(XI ' Q2) ~G(X2' Q2)C(Xl, Q2)A

C(X2' Q2) aLL,since the PYTHIA is an unpolarized generator.

G(x , Q2) (~G(x, Q2)) is the gluon (helicity) distribution function at a given Bjorken's x and momentum
scale Q2. Xl and X2 are fractions of the proton momentum carried by the gluon. The quantity aLL is thegg -+ J/'l/Jg subprocess asymmetry at COM.6) In fact,
to determine aLL, one has to disentangle I So and 3 Po
contributions to the matrix elements. Figure 2 shows
the asymmetries with three different ~C inputs,7) but
neglecting 3 Po contribution. From these asymmetries,
one can show the experimental sensitivities. Although
the size of asymmetries are rather smal~ (1 to 1.5% at
maximum), there is significant statistic at lower Pr region, Pr < 11 or 7 (GeV /C)2 for .jS = 500 and 200
Ge V, respectively.
We will extend this work further. For example, we
can evaluate an analysis program and method by showing how well one can recover an input gluon and its
helicity distribution.
! . . sop ~v : 1.~< 11 ,2 .
• GS95LO(A~ ! ; ! , ,• $S~LQ(B~"-+ " +-'+"'~'-' I-'"
d~S95L(?(C~~, : ! . ' . ..

~.IJol;+:r::pl. rl:"" ~~T;n-'~-l'

1.2 dIll < 2.4

I ;-1-~--.sOO-G-~.

,'2QO Ge-0.01 0

2

4

6

8

101'2~1~ ' 16 '"lj8~20

PT (GeV/c)

o 2

4

6

8 10 12 14 16 18 20
PT (GeV/c)

Fig. 2. Prediction of J /'1/; spin asymmetry at PHENIX.

Fig. 1. Prediction of J / 'I/; cross section.
The asymmetry ALL can be written in terms of crosssection,d3~(JALLd 3 (J= E d 3p / E d 3p .
d3~(JReferences
1) H. En'yo et al.: RIKEN Accel. Prog. Rep. 31, 52 (1998).
2) P. Cho and A. K. Leibovich.: Phys. Rev. D 53, 150(1996); Phys. Rev. D 53, 6203 (1996).
3) T. Sjostrand.: Comput. Phys. Commun. 82, 74 (1994).
4) B. Cano-Coloma et al.: Nucl. Phys. B 508, 753 (1997).
5) CDF Collaboration.:
Report No. Fermilab-Conf95/128-E (1995) .
6) A. Tkabladze and O. Teryaev.: Phys. Rev. D 56, 7331
(1997).
7) T. Gehrmann and W. J. Stirling.: Phys. Rev. D 53,
6100 (1996).

To extract the spin dependent cross section E d 3 p ,45

RIKEN Accel. Prog. Rep. 32 (1999)

Measurement of the Proton Polarization
at 21.6 GeV Ie for AGS E925
N. Hayashi, H. En'yo, Y. Goto, T. Ichihara, Y. Kondo, Y. Nakada, M. Nakamura, N. Saito,
H. Sakai, H. Sato, H. Okamura, M. Okamura, and T. Wakasa[RHIC, AGS, Spin, Asymmetry, Polarized beam, Polarimeter]
The polarization measurement of the proton beam
up to 250 GeV / e is very important to lead the
RHIC/Spin project!) into success. One of proposed
methods utilizes the transverse spin asymmetry, AN,in p t + C --t 7r± + X. The experiment E925 of the
AGS was proposed to confirm independence of thisasymmetry from the target material and beam energy.
The experiment uses the polarized proton beam extracted from the AGS and the beam polarization isdetermined by measuring the AN in ~p elastic scattering. The first E925 run with the carbon target was
performed on November 1997. This article describes
the measurement of the beam polarization.
The design concept of the polarimeter was described
previously.2) We measured the ~p elastic scattering
asymmetry at t = -0.15 (GeV /e)2, where t represents the square of the momentum transfer. Analyzing power in this momentum region was obtained
to be AN = 0.040 ± 0.004 from a phenomenologicalanalysis based on previous experimental data. 3 ) The
present set-up is shown in Fig. 1. From the previous set-up only the position of the forward counters(FRA, FLA, FRB, and FLB) were modified. Since
we used a polyethylene (CH2 ) target, we subtracted
carbon contributions from the raw data.

107- 108 per burst. (one burst every 3 seconds.) The
events were triggered by only the backward (recoil)arm counters, namely B1 ® B2 ® B3 ® B4 (B1 denotes
BL1 and/or BR1 , and B2 , B3 and B4 denote similarly). Trigger rate was up to 70-80 events/burst. We
reversed the magnet polarity of 7r spectrometer occasionally in order to take both 7r+ and 7r- for the pionarm.
Raw asymmetries E were extracted from the following formula:(1)

NL (N R ) is the number of counts detected in theleft (right) arm and the superscript t (.l.) indicatesup (down) polarization. Systematic asymmetry errors,
detector acceptance, and beam intensity for each polarization state are almost canceled by using this formula.
We have obtained the asymmetry for the C H 2 target:ECH2

MAGNET __ • ____ ••••••••••••••••••••••••• -

OFRB
oFLB

Fig. 1. A schematic drawing of the E925 set-up. The
C-TGT (Carbon target) and Cerenkov counter arm isfor the pion detection part. The other parts, CH2 target, two backward arms, and four forward counters consist ~p elastic part.
Initially, the proton beam momentum was 22.75
Ge V / e, but a rather strong depolarization resonancein the AGS was found at this energy. Thus, we set
the beam momentum at 21.6 GeV /e in order to preserve the beam polarization. Beam intensity was about

46

(2)

The error indicated above is only statistical one. The
asymmetry Ep of the proton was deduced from the ECH2
after subtracting the carbon contributions as:
Ep

OFRA
0FLA

= 0.0107 ± 0.0023.

= 0.0108 ± 0.0024(stat.) ± O.0003(syst.).

(3)

The first and second uncertainties are the statisticaland systematic errors, respectively. The systematic
error depends on the asymmetry EC for the carbon
target, which we had to assume.
The polarization P was determined from P =Ep/AN asP = 0.271 ± 0.059(stat.) ± 0.028(syst.).

(4)

The error of AN contributes to the systematic error.
References
1) H. En'yo et al.: RIKEN Accel. Prog. Rep. 31, 52 (1998).
2) H. En'yo et al.: RIKEN Accel. Prog. Rep. 31, 173(1998).
3) D. G. Crabb et al.: Nucl. Phys. B 121, 231 (1977); M.
Borghini et al.: Phys. Lett. B 36, 501 (1971); A. Gaido
et al.: Phys. Lett. B 61, 103 (1976).

RIKEN Accel. Prog. Rep. 32 (1999)

Performance of PHENIX EM-Calorimeter for Spin Physics
Y. Goto, K. Imai, N. Saito, and H. Torii[ pp interaction, Structure function, Spin, Asymmetry, Polarized beam]
EM calorimeter plays an important role in both theheavy ion physics and the spin physics in the PHENIX
experiment at RHIC. 1 ,2) To cover both physics topics,
it is required to cover a wide range of energies withgood linearity, resolution, and hadron rejection. The
heavy ion physics wants an access to the low PT region e~tending down to a few hundred Me V / e in order to detect the soft photon signal from the quark
gluon plasma (QGP) state. The detection of soft plural photons in this region requires rejection of low energy anti-neutrons and other hadrons with the timing
measurement. It requires the threshold energy as low
as possible. In the spin physics at Vs = 500 GeV, a copious weak bosons are produced and the maximum energy of decay electron/positron reaches approximately
80 Ge V. Prompt photon measurement also requires a
PT range up to 30 Ge V / e.
The EM calorimeter was originally designed for theheavy ion physics. The spin physics requires the nonlinearity less than 1% for the steep slope cross section
measurement of prompt photon and 7r 0 production. To
fulfill the requirements, we have to perform a high energy beam test of the EM calorimeter, a test of theelectronics, and a development of the necessary software. We also need a good calibration system. We
have a cosmic muon system for the absolute and relative energy scale determination, and a laser system tocorrect the time dependence.
The high energy beam test was already done at
the CERN /SPS H6 beam line. One lead- scintillator(PbSc) super module and 4 lead glass (PbGI) supermodules were placed on a movable platform to change
the position and angle of the incident beam on thecalorimeter. All the necessary data which we planned
were obtained, although some of them had a less statistics than expected. The following is the summary ofour data sets:• Energy scan data (6, 10, 15, 20, 30, 40, and 80
GeV /e e- beams at 0 degree on the calorimeter)• Non-perpendicular incident beam data (10, 15,20,
30, and 40 GeV /e e- beams at 10 and 20 degrees
on the calorimeter)• Position scan data (20 GeV /e e- beam)• Hadron response data (40 GeV / e 7r+ beam)• Energy calibration data (10 GeV /e f-l- beam for
PbSc and 10 GeV /e e- beam for PbGI)The energy scan data will serve for the energy linearity and resolution measurements. The non-orthogonal

incident beam data and the position scan data arenecessary mainly for the software development: e.g.,
shower reconstruction program and shower simulation
program. Hadron response data can be used for the
hadron background estimation. We took energy calibration data with a purpose to calibrate the energy
scale tower by tower.
The data analysis is now in progress. Figure 1
shows a preliminary result of the PbSc response for the
40 GeV /e e-, 7r+ and f-l+ beams. Preliminary muonand laser calibration have been done. The peak position for the 40 GeV /e e- beam and the peak positionsfor 7r+ and J.L+ beams are all consistent with the predictions by calculation.
Further work we have to do is the test of electronics
for the calorimeter. Some parts of electronics design
were modified to cover the high energy region. We
have to check the front-end-module to confirm the energy coverage and linearity of the calorimeter. As forthe software development, a fast Monte Carlo simulation program is necessary to make our simulation
program run faster. We have to utilize the results ofour high energy beam test, such as the shower shape,
to make the simulation program reproduce the real
shower shape precisely. Shower reconstruction program also has to be checked and developed to obtain agood, / 7r 0 discrimination and a good electro-magneticshower/hadron-shower discrimination at the higher energy region.

40GeV beam

l~[
00

l~

Preliminary
n+
1

10

20

30
50
40

AI
40

50

GeV

J.l+MI

30
20

10
0

Fig. 1. Preliminary result of PbSc response for the 40
GeV Ie e-, 7r+ and fL+ beams.

References
1) H. En'yo et al.: RIKEN Accel. Prog. Rep. 31, 52 (1998).
2) Y. Goto et al.: RIKEN Accel. Prog. Rep. 31, 54 (1998).

47

RIKEN Accel. Prog. Rep. 32 (1999)

Construction and Quality Assurance of the Large Muon
Identifier Panels for PHENIX at BNL
K. Kurita, A. Taketani, Y. Goto, M. Ishihara, T. Ichihara, Y. Watanabe, N. Saito, N. Hayashi,
H. En'yo, Y. Nakada, H. Sato, K. Imai, Y. Mao, and W. Tian
[PHENIX experiment, Muon Identifier, Production factory]
We have built, installed, and tested forty PHENIX
Muon Identifier (MUID) large panels in Brookhaven
National Laboratory (BNL) as shown in Fig. 1. 1- 3 )Twenty small MUID panels which cover the large
panel gaps were fabricated in Japan and shipped to
BNL for installation during the large panel construction period. The detail of the MUID fabrication procedure at Japanese factory is described elsewhere inthis report. 4 ) Since the same fabrication procedure wasadopted in both MUID factories, in present article wereport our quality assurance (QA) test results of MUID
tubes and the installed panel test in PHENIX Experimental Hall (PEH).

tubes which passed the leak test into wooden crates
before they are dried. Therefore the water vapor wastrapped in the crates and diffused into the tubes on
their way to BNL.
It turned out that the bad tubes can be spotted bysimply measuring the resistance (Rae) with a megaOhm meter between the anode and cathode of a tube.
Normal tubes had resistance above 100 GO but thebad tubes showed much lower values as low as 10 MO.
We could recover bad tubes by flowing a large volumeof dry gas before our QA procedure. Most tubes recovered to 100 GO in a day or two. The tubes whichwere recovered by this method were about 4000 out of
10000 total tubes we used for the large panel construction. When we informed this problem to the Italianfactory, they changed the shipping procedure so thatlittle water is left in the tube container. The low Rae
problem disappeared after the alteration of tube shipment procedure.
Though most bad tubes were recovered, their failure
rate in our QA test was about twice higher than thatof a good batch of tubes. Final QA results are summarized in the Table 1 above. Once passed the QA test,
the recovered tubes had the same efficiency as that ofother good tubes.
Table 1. Summary of the results of tube QA test.

Fig. 1. Photograph of PHENIX Experimental Hall(PEH):
MUID panels are located behind the lamp-shade shape
MUON magnets.
The MUID detector's sensitive element is the rectangular shape plastic tubes (8.3 cm (W) x 1 cm (H) x
510/502 cm (L)) supplied by an Italian company,
pol.hi.tech. The same company supplied the tubes to
the Japanese factory. However, we had a major problem with the tubes, which Japanese factory did notexperience.
/
It was a large leakage current between the cathodeand anode when a high voltage was applied on them.
The cause turned out to be the humidity inside thetubes. When pol.hi.tech tested the gas tightness before
the shipment of the tubes to BNL, they submerged thetubes under water. If a certain amount of air bubbles
a tube was observed from a tube, it was marked as aleaky tube and thus rejected. They then packed the48

Tube length
510cm
502cm
total

Total #
4,876
5,256
10,132# failed
764
740
1,504

Failure rate
15.7%
14.1%
14.8%

The construction and installation of all the MUID
panels were finished in late September 1998, and currently the installed panel test is under way. We
brought in two portable gas supply stations: one insouth and another in north of PEH. We flow pure CO 2
into panels. Due to the limitation of the number ofsupply lines, we can supply gas only to three large
panels at a time.
The panel-check procedure in PEH is following: (1)Flow enough CO 2 to flush all unwanted components,
such as oxygen and humidity, through tubes which normally takes two days. (2) Slowly raise the HV allowing
over current no more than 10 j.LA. (3) Look at the signal
shape on an oscilloscope for each channel at full operating voltage 4.3 kV. (4) Measure the counting rate ofcosmic ray and compare with the panel test result in
the factory.
We have checked 36 large panels and all 20 small
panels. In general the panel performance turned out
to be good, but we found a few minor problems. They
are: (1) We have to flow more gas to the panels withbad tubes before applying high voltage. (2) We can
not apply high voltage at all on one segment of a small
panel which corresponds to 1/6 of a panel. (3) There
are about 20% of tubes which show sparks of various

levels. They are expected to be suppressed by further conditioning with more gas flow and high voltage
cleaning.
References
1) H. En'yo et al.: RIKEN Accel. Prog. Rep. 30, 33 (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).

49

RIKEN Accel. Prog. Rep. 32 (1999)

Installation and Quality Test of Muon Identifierin Japan for PHENIX
A. Taketani, K. Kurita, M. Ishihara, T. Ichihara, Y. Watanabe, N. Saito, N. Hayashi,
H. En'yo, Y. Nakada, H. Sato, K. Imai, H. Torii, T-A. Shibata, T. Sakuma,
E. Taniguchi, Y. Mao, Z. Li, J. Tojo, M. Sekimoto, and H. Funahashi[PHENIX experiment, Muon Identifier, Production factory]
The fabrication of muon identifier (MUID) was doneat KEK and at BNL. This paper will summarize the20 of small panels fabricated in KEK. The muon identification plays quite important role at RHIC spin
project. 1) The muon detector will cover from 10 to
35 degrees in azimuthal angle. The MUID panel consists of Iarocci tubes,2) electronics, frame, and covers.
The size is 2.9 m(H) x 4.4 m(V) and weight is 600 kg,
which is fabricated in KEK.
The Iarocci tubes were fabricated in Italy andshipped to KEK factory. There are two types oftubes. One is 2.5 m and another 3.82 m long, so called
short and long tubes, respectively. We have tested
2031 short tubes and 1165 long tubes.
At first, the resistances of anode-anode, anodecathode, cathode-cathode, and capacitance of anodecathode are measured. The tubes which are identified
as broken wire or broken connection are rejected. The
electrically qualified tubes are tested with 30 cm-waterequivalent overpressure and measured for their leakage.
The tubes with relatively small leakage are fed withpure C02, and then a high voltage up to 4.8 KV has
been applied for five days. At the end of the burn in,
the pulse height spectrum of cosmic ray signal is taken.
Also, single count rate by the cosmic ray is measured
for each tube. These values are used to identify theoperational tubes.
105 tubes are recovered by adding glue in the cracks
between jacket and end plug. The tubes which arerejected by too much current during burn in or by badsignal-to-noise ratio were recovered with 5 more daysof conditioning.
About 150 tubes were processed per week. The processes of tube quality assurance are proceeded independently from panel assembling. Table 1 shows thereasons of final failure and number of tubes. Finally,
2840 tubes were qualified for the installation.
Table 1. Number of failed tubes and the reasons.
Reasonelectricallygas leakover current
signalShort Tube
24
58
8
35

Long Tube
41
173
4
13

Total
65

231
12
48

The assembling procedure has been described
before. 3 ) Figure 1 shows a photo of flipping panel. At
50

KEK factory there are no air conditioners to maintain stable temperature and low humidity. Humidity
causes problems with high voltage(HV) circuit. We
try to keep clean and dry all HV equipments during
the burn in period, especially for HV connectors. To
avoid the humidity in the panel volume, dry nitrogengas was fed into the space among tubes, panel frame,and covers at the end of every single panel fabrication.
It prevents high voltage sparks at outside tubes quite
well.

Fig. 1. Photo of flipping panel.
Temperature excursion affects during day and nighton the accuracy of the tube leakage rate measurement.
When temperature of the tube changes, pressure in
the tubes might be changed since tubes are closed systems. We evaluates the relationship among the insidepressure, outside pressure, and temperature by simple
measurements. The leakage rates were corrected.
The signal shapes are checked by the oscilloscope
and the single count rate from cosmic ray are measured
for individual tubes. About 5 percent of the two packs
are noisy due to the discharging in the tubes. We try
burn in at first panels for additional hours, and thenthe problem goes away. These discharging are regarded
as recoverable by additional burn in, thereby at thismoment.
I t takes for almost one month to assemble the firstpanel by five physicists and two technicians. We reviewed all procedure to reduce the time very carefully.
At the end of the fabrication, it takes 3 days typically.

Most of the efforts are reducing the total number ofsteps of person walking during the assembling and installing of two packs of tubes. Also a time sharing
method works it well. In the morning, technicians install two packs, then a physicist checks gas leakage
in the early afternoon. In the late afternoon , technicians install the preamps. The burin in takes anotherfew hours and another physicist checks all signals. We
were succeed to reduce the fabrication time and man
power.
The panel is relatively heavy, big and not rigid.
Three aluminum rods of square cross-section are attached under the panel. They across the panel to support the tube weight through the cover. Two rods areattached over the longer frames. In order to attach therods, the blocks are installed in the frame permanently.
Rods are fixed by bolts that are easy to install and remove. A single crane can lift the panel by 3 person
safely in 30 minutes.
We chose the surface shipping although the delivery
time is quite different. The biggest concern to reject
the airplane is an environmental pressure change during the take-off and landing. The pressure decreases
from 1 to 0.8 atoms in 15 minutes at take-off. We areafraid that tubes might expand with rapid pressurechange and break. Also, during the landing the tubes
may suck the dusty environmental air.
Five panels are stacked in the same package due tothe crane capacity at the factory. The 10 cm thickstyrofoam separates each panel. Three squared crosssection aluminum rods are attached under the eachpanel to enable a horizontal handling. An aluminized
plastic bag wraps five panels together. The bag is
pumped out and then closed in order to shut the dirty
and humid air out during the transportation.
We shipped four times. Each shipment lasts for one
month. After arriving at BNL, 10 out of 20 panels are
opened and investigated. One percent of the tubes had
broken wire.
We started the fabrication in December 1997 andfinished at June 1998. The last 5 panels are shipped
to BNL in early July 1998.
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).

51

RIKEN Accel. Prog. Rep. 32 (1999)

R&D of CNI Polarimeter with Carbon Target
J. Tojo, A. Ichikawa, K. Imai , Y. Kondo, R. Muramatsu, J. Murata,
M. Nakamura, H. Takahashi, K. Yamamoto, Y. Goto, N. Hayashi,
M. Ishihara, K. Kurita, M. Okamura, and N. Saito

As a RHIC polarimeter, the pC Coulomb Nuclear Interference (CNI) polarimeter using the elastic protoncarbon scattering in the CNI region was recently proposed. 1 ,2) The maximum analyzing power of 2 to 4%
is expected at the kinematic region where the energyof the recoil carbon ion is below 1 MeV. This regionis suitable for polarimetry. The energy of such carbon ions has to be measured in coincidence with thebeam pulse in order to identify the elastic scattering
as a function of the momentum transfer squared. We
proposed to use the combination of two micro channel
plates (MCP) and a silicon strip detector (SSD) for
the detection of recoil carbon ions as shown in Fig.l.
Both the time-of-flight (TO F) measurement between
two MCPs and the pulse height measurement with the
SSD provide the particle identification and the energyof recoil carbon ions. With the proposed polarimeter,
the beam polarization can be measured within a few
minutes at an accuracy of 10%. Uncertainty on the
hadronic spin flip amplitude dominates the ambiguityof this measurement. The quality of the RHIC polarized proton program heavily depends on the success ofthe development of the polarimeter.
Test experiments to detect such low energy carbon
ions with the MCP were carried out at the Tandem
Van de Graaff in Kyoto University. A 10 MeV proton
beam and a thin carbon target of S J-lg/cm 2 in thickness were used to measure the elastic proton-carbon
scattering. The scattered protons were detected witha plastic scintillator mounted on a photomultiplier.
In order to maximize the detection efficiency and to

MCP

I~~~::k~~~/~~///I
"

/

I,

'~"

'\

"I

I

',--"

C foilelectrostatic mirror

//

1//

\

C targetpbeam
Fig. 1. Schematic view of the recoil arm.

52

SSD

design the polarimeter, the recoil carbon ions were detected with the detector system including MCP. Three
configurations were tested as the detector system; (1)only MCP, (2) combination of MCP and SSD(Au surface) with an electrostatic mirror , and (3) combinationof MCP and a thin carbon foil (5 J-lg/cm 2 ) with an electrostatic mirror. From the TOF measurement , which
can be converted to the energy spectra of the carbon
ions, the low energy carbon ions as low as 200 ke V
were successfully detected with each setup. From theefficiency measurement , the method shown in Fig. 1
was found suitable for detecting lower energy carbon
ions.
We are developing a Si strip detector and a fast
preamplifier in collaboration with BNL instrumentation division. Si detector simulation shows that we candetect the recoil Carbon down to 200 keV. The purposeof the customized design is to minimize the noise dueto the large capacitance of commercially available Si
detectors. A minor modification to one of the preamplifiers which were developed by the instrumentation
division earlier will be made to accommodate our Si
detector. The performance of the Si detector and thepreamplifier will be evaluated on a test bench prior to
the beam test at the BNL-AGS.
The Si detector is expected to be fabricated by the
middle of Dec. 1998. Then, the Si detector in combination with MCP will be tested using the proton
beam at the Kyoto Tandem for the carbon detectionin early Jan. 1999. Then, finally the polarization measurement with the proposed setup will be performed at
BNL-AGS using the polarized proton beam expected
to be available in Mar. 1999. The experiment E9S0 will
use two recoil arms to measure the analyzing powerfor proton-carbon elastic scattering in the CNI region-t = 0.003- 0.01 (GeV Ic)2 at beam momentum of
23 GeV Ic.
References
1) Proc. Workshop on Hadron Spin-Flip at RHIC Energies,
RIKEN BNL Research Center, July 21-Aug. 22, edited
by T. D. Lee., Vol. 3 (1997).
2) B. Kopeliovich: High-Energy Polarimetry at RHIC,
hep-ph/9801414.

RIKEN Accel. Prog. Rep. 32 (1999)

Plan for the PHENIX Computing Center in JapanY. Watanabe and T. Ichihara
Now the start of experiments with RHIC 1) (Relativistic Heavy Ion Collider) is close , within a year. As
the construction of accelerators and detectors is goingat a high pace, the computer system has to be prepared in real earnest since the most important partis data analysis once the experiments start. As wereported in the last issue of this report,2) the RCF 3 )(RHIC Computing Facility) is going to be establishedat BNL 4) (Brookhaven National Laboratory) which isthe central computer center for all four experiments
at RHIC, and we are also preparing to build a similar
facility named CC-J (PHENIX Computer Center inJapan) at RIKEN Wako campus as a base of analysis
for Japanese and Asian colleagues.
The purposes of the CC-J are focused to the following three points:• Detector simulations and theoretical model calculations: These CPU intensive tasks are invaluablefor the extraction and understanding of resultsfrom PHENIX measurements. The CC-J will handle the bulk of the simulation tasks of PHENIX,
and it should be noted here that both the RCF
and the PHENIX collaboration already assume
the CC-J to provide this service.
• PHENIX regional computing center in Asia: The
CC-J is intended to be a regional center for thesimulation and analysis of PHENIX physics results. Existence of a regional access to the computing and physics data will encourage a strong
participation from the PHENIX collaborators ofJapanese and Asian regions. Primary DST (Data
Summary Tape) production will take place in
the RCF directly from the raw data, and so the
CC-J will emphasize micro-DST production andlater physics analysis. The CC-J will significantly
enhance the prospects in timely production ofphysics results from PHENIX.
• SPIN physics analysis: Although the workforce forcarrying out the SPIN physics program at RHIC
is centered at the RIKEN BNL Research Center,
it is very important to keep maintain a strong locus of activity in Japan. The importance of thisprinciple has long been accepted by the RIKEN
BNL Research Center and by the RIKEN head-quarters. The CC-J should help draw the attention of Japanese people, attract new people, andserve in its home ground as a showcase of thisRIKEN project.
In order to realize such purposes, we wrote a
proposal 5 ) stating RBRC 6 ) (RIKEN BNL ResearchCenter) should build a strong channel with SPIN
physics at RIKEN , and intends to establish the CC-J
after JFY 1999 by three years. We let the proposal bereviewed by an advisory committee consisting of four
excellent physicists who have also a good ability incomputers. Some important numbers which describe
a planed capability of the CC-J are following Table 1.
Table 1. Planed scale of the CC-J.
Total CPU power
Fixed disk
Tape robots capacity
Speed of data archive
Total capacity of tapes'" 10,000 SPECint95
15 TBytes
100 TBytes
110 MBytes/s
250 TBytes/year

These numbers indicate that the size of CC-J will become about 1/3- 1/2 of the RCF's.
We are making two prototype facilities in this year.
One is the simulation and data analysis facility, andanother is the data duplication facility to transfer datafrom BNL to RIKEN. The former consists of 10-unit
LINUX boxes (each box has two Pentium II CPUs)
as a PC farm and one-unit SUN E450 as a RAID fileserver. For the latter, we will purchase a tape drive(STK Redwood) to attach to the STK silo of RCF.
We acknowledge Prof. Hideto En'yo, Prof. Hideki
Hamagaki, Prof. Jyunsei Chiba, and Prof. Ryugo
Hayano for their earnest discussions with us.
References
1) http://www.rhic.bnl.gov/
2) Y. Watanabe et al.: RIKEN Accel. Prog. Rep. 31 , 171(1998) .
3) http://www. rhic. bnl.gov/htmljRDG.html
4) http://www.bnl.gov/5) http://spin. riken. bnl.gov/ccj/doc/plan/6) http://www.rarf.riken.go.jp/rarj/rhic/bnlj

53

RIKEN Accel. Prog. Rep. 32 (1999)

A High-spin Isomer in 143N dx. H. Zhou, H. Tsuchida,* Y. Gono , A. Odahara, E. Ideguchi, T. Morikawa, M. Shibata, H. Watanabe ,M. Miyake,* T. Tsutsumi,* S. Motomura,* T. Kishida, S. Mitarai, and M. Ishihara[NUCLEAR REACTION: ISO + 130Te at Elab = 80 MeV; ,-,-t coincidence measurementl
High-spin isomers were observed systematically in
the N = 83 isotones with proton number Z from68 to 61,1) the characteristics of these high-spin isomers can be well described in the framework of adeformed independent particle model (DIPM).2) The
DIPM calculations assigned the isomers to be of thestretched configurations [v(f7 /2 h 9/2 i I3/2)7r(hi1/2) lt9/2
and [v(f7 /2h9j2i13/2)7r( d~/2hi1/2)Jt7 in the odd andodd-odd N = 83 isotones, respectively. I) These configurations may induce oblate deformations, while thelower-spin states have near spherical shapes. Therefore, the high-spin isomers in the N = 83 isotones
were interpreted to be caused by sudden changes innuclear shape, which was confirmed by the deformation parameters of the yrast isomers in 147 Gd deduced
from the experimental quadrupole moments. 3,4) The
purpose of the present investigation is to search forthe corresponding high-spin isomer in 143Nd with aproton number of 60. The level structure of 143Nd wasstudied by several groups,5-S) but no high-spin isomerhas been reported so far.
The excited states in 143Nd were populated using
the 130Te(lsO, 5n)143Nd reaction at a beam energy of
80 MeV. Measurements of delayed ,-, coincidences,,-ray angular distributions, and ,-ray linear polarizations were performed. Linear polarization measurements are useful in determining the electric or magnetic character of ,radiation. By combining the results of ,-, coincidences, linear polarization, and angular distribution measurements, a new level scheme
is proposed to 143Nd as shown in Fig. 1. The level at8989 ke V with spin and parity values of 49/2+ is identified to be an isomer. Above the 8989-keV isomer the, rays have considerable populations. This makes it
possible to extract the half-life of the 8989-keV isomerfrom the ,-,-t data. Figure 2( a) shows the time distribution between the two ,-ray groups, which lie aboveand below the isomeric state, respectively. And thetime distribution between prompt coincidence , rays
is presented in Fig. 2(b) for comparison. The latter
distribution represents the time jitter of the detection
system and its associated electronics. A half-life of
35 ± 8 ns was extracted for the isomer at 8989 ke V
from an exponential fit to the curve in Fig. 2(a).
The deformation parameters (3 for the yrast statesin 143Nd are calculated with the deformed independent particle model. The calculation shows that, below
the 49/2+ isomer, the yrast states have near spherical
Department of Physics, Kyushu University

54

143Nd

Fig. 1. Level scheme of 143Nd proposed in the present
work.

Time (ns)Fig. 2. (a) The time distribution between the two ,-raygroups lying above and below the isomeric state, respectively, and (b) the time distribution between prompt
coincidence, rays.

shapes with small deformations ranging from 0 to
-0.1, but the deformation is increased suddenly at
the 49/ 2+ isomeric position. A f3 value of -0.18 is
obtained for the 49/ 2+ isomer in 143Nd. In 143Nd
the 49/2+ isomer has a full neutron configurationof [(d;}2)of7/2h9/2i13/2], the large deformation of the
49/2+ isomers is caused by the two (d;/2)0 neutron
holes in this configuration, since the large quadraticterm in the dependence of the energy of the d 3/ 2 orbit on f3 drives the nucleus towards a large oblate
deformation. 2) As the isomers in the heavier isotones ,the occurrence of the 49/2+ isomer in 143Nd can beinterpreted as a shape isomer.
References
1) A. Odahara et al.: Nucl. Phys. A 620, 363 (1997) .
2) T. Dossing et al.: Phys. Scr. 24, 258 (1981) .
3) O. Hausser et al.: Nucl. Phys. A 379, 287 (1982).
4) E. Dafni et al. : Nucl . Phys. A 443, 135 (1985) .
5) O. J. Tekyi-Mensah et al.: Phys. Rev. C 50, R1759(1994).
6) S. M. Aziz et al.: Phys. Rev. C 41, 1268 (1990).
7) D. D. Caussyn et al.: Phys. Rev. C 43, 2098 (1991).
8) M. Fauerbach et al.: Phys. Rev. C 58, 826 (1998) .

55

RIKEN Accel. Prog. Rep. 32 (1999)

In-Beam Gamma-Ray Study with HSIB of 145mS m
E. Ideguchi, Y. Gono, T. Kishida, T. Kubo, X. H. Zhou, T. Morikawa, A. Odahara, H. Tsuchida,
M. Shibata, H. Watanabe, M. Miyake, S. Motomura, T. Tsutsumi, K. Yoneda,
B. Cederwall, T. Back, T. Murakami, and M. Ishihara[NUCLEAR REACTIONS 160(136Xe, 7n)145mS m , 12C(145mSm, xn)157-XEr, High spin isomer beam]
Recently, the search for the hyperdeformed states
has collected much attention after they were predictedin the extremely high spin states.!) Large Ge arrays
such as EUROBALL and Gammasphere have been
constructed in order to investigate such high spinstates. 2) However, unambiguous experimental evidence
to confirm the existence of the hyperdeformed states
has not been found yet. The most important experimental difficulty seems to be how to make such an
extremely high spin state.
The High Spin Isomer Beam (HSIB) was developedin RlKEN Accelerator Research Facility in order to
excite very-high spin states. Since the HSIB itself has ahigh angular momentum, the secondary fusion inducedby HSIB will excite much higher spin states.
The secondary fusion experiment induced by HSIB
was carried out by using the 12C(145msm, xn)157-XEr
reaction. HSIB was produced by using the 160(136Xe,7n)145mS m reaction. 136Xe beam was accelerated to
7.6 MeV /u by RIKEN Ring Cyclotron and maximum
beam intensity of 136Xe was about 100 pnA.
In order to avoid a melting problem possible withusual thin metal foil due to the high intensity of primary beam, the CO 2 gas target system, which was
originally developed in Kyushu University,3) was used.
Pressure inside the gas cell of the system was kept
50 Torr during its operation. This condition corresponds to the thickness Img/cm 2 of 16 0. The lengthand diameter of the cell were 10 cm and 6 mm, respectively. After the gas target the HSIB was focused on
the usual primary target position of RIPS 4) by using asolenoidal magnet, and it was separated from the primary beam and transported to the final focal plane byusing RIPS.
At the final focal plane the 145m Sm isomer beam
was obtained at the intensity of more than I0 5pps.
The secondary target of 12C was used with the thickness of 1.86 mg/cm 2 . The Ge telescope system 5) wasused to detect , -rays with high efficiency and to correct Doppler effects. In the secondary reaction to use
HSIB the velocity of the secondary beam is expected to
be about 10% of the speed of light , which will cause aserious Doppler broadening. The Ge telescope system
consists of a segmented Ge and a Clover Ge detector.
The segmented Ge detector, which was a planar typeGe and was segmented into 25 pieces, was set in frontof the Clover detector. This setup can determine theangle of a , ray emitted from the target with the information which segment was fired. These results were
utilized for Doppler correction. Sixteen Ge detectors
were also used to make a " coincidence measurement
together with the telescopic Ge system.
In the secondary fusion experiment a large back56

ground level in the , -ray spectrum is due to the decay,-rays from the high spin isomer. In order to reduce
this background of isomer the neutron detectors fromGettingen University6) were used as a gate together
with the Ge detectors because the neutrons and ,-rays
are emitted at the same time in the secondary fusion
reaction.
In Fig. 1, the , -ray spectra without (a) and with (b)the information gated by the neutron detectors areshown, respectively. The background from the highspin isomers were much reduced by the neutron gate.
In the spectrum gated by neutron detectors, Doppler
shifted, peaks are observable. These peaks were corrected by using the Ge telescope as shown in the frame(c) in Fig. l.
Data analysis of the secondary reaction experimentis still in progress.

(al

)~k~"
JM~

(/)

c

8 ~

I

)J~
OJ

I

C

::J

8 200

~\~

i
j

(el

~~I~

"'"

"~-

E~ (keV)Fig. 1. Gamma-ray spectra obtained at the secondary
target position. (a) Without a neutron gate, (b) Witha neutron gate, and (c) Doppler corrected spectrum.

References
1) S. Aberg: Nucl. Phys. A 557, 17c (1993).
2) C. W. Beausang and J. Simpson: J. Phys. G 22, 527(1996).
3) K. Sagara et al.: Nucl. lnstrum. Methods Phys. Res. A
378, 392 (1996).
4) T. Kubo et al.: Nucl. lnstrum. Methods Phys. Res. B
70, 309 (1992).
5) E. ldeguchi et al.: RlKEN Accel. Prog. Rep. 27, 121(1993) .
6) V. Kunze et al.: Nucl. lnstrum. Methods Phys. Res. A
361 , 263 (1995).

RIKEN Accel. Prog. Rep. 32 (1999)

a-Decays of 1959,mAt and 199Fr
Y. Tagaya, S. Hashimoto, K. Morita, A. Yoshida, Y. Pu, T. Ariga, K. Ohta,
T. Ishizuka, T. Minemura, 1. Hisanaga, T. Motobayashi, and T. Nomura[NUCLEAR REACTION, 169Tme6 Ar, ex6n), 169Tme6 Ar, 6n), 1959,m At, 199Fr, ex-decays, Gas-filled separator]
The ex-decay of 195 At was first studied by Treytl andValli 1) and later by Leino. 2) Although possible assignment of the ground-state ex-decay was reported in Ref.
2, it has not been adopted in recent compilations 3)
presumably due to the poor statictics and complicatednature of the observed decays. We have therefore reinvestigated the 195 At, and have successfully identified the ex-decays from both the ground-states (g) andisomeric-states (m) produced in the 169Tme6 Ar, ex6n)
reaction. In addition, the first evidence for the ex-decayof 199Fr produced in the 169Tme6 Ar, 6n) reaction has
been found.
Metallic 169Tm targets of about 0.44 mgjcm 2 thickness evaporated onto a 13 /lm thick aluminium foil
were fixed on a rotating disk, which was 150 mm in diameter and rotated at 10 rps. Each piece of the target
effectively covered 30°, and there was 30 0 dead space
between two neighbouring targets. The pulsed 36 Ar
beam with 8.3 ms duty-on and 8.3 ms duty-off periods
was used. The bombarding energy and beam intensity
were monitored by measuring the elastically-scattered
36 Ar with a small Si-detector placed at 46.10 with respect to the beam direction. The beam intensity was
1.0 x 10 12 S-l on the average, while the beam energy of
273.6 MeV from the cyclotron was degraded throughan aluminium foil down to 215 ± 5 MeV.
Reaction products recoiling out of the target wereseparated from the primary beam with a gas-filled recoil separator GARIS,4) and were detected with a twodimensional position sensitive detector (PSD) placedat the focal plane of the GARIS . A Si detector of almost same size placed 0.5 cm behind the PSD was used
as a veto counter, which turned out quite effective inorder to reduce the backgrounds such as light particles
coming into the PSD. A micro-channel-plate (MCP)
assembly was also placed 70 cm upstream of the PSD.
In the analysis, all the PSD signals in coincidencewith MCP signals were regarded as the evaporation
residues (ER), while those without MCP signals weretreated as the possible ex-decay events. Three successive events consisting of ER, first ex-decay (ex 1),
and second ex-decay (ex2) in this time sequence weresearched on condition that they occured within thesmall area on the PSD at adequate time intervals, ~hand ~t2 ' which are those between the first two and second two events, respectively. The present assignmentis based on the agreement of the ex2-decay properties(energies Ea and lifetimes T 1/2) with the properties
previously known.
All the decay properties concerned with 1959,m At

and 199Fr were tabulated in Table 1. Assignment of
the 195m At was based on the observation of the ER195m At_ 191m Bi correlations with a low background (SeeFig. 1) and on the agreement of the 191mBi ex-decay energy and lifetime with literature values. 5,6) Assignmentof the 1959 At was based on the observation of the ER1959 At_ 191g Bi correlations with a low background andon the agreement of the 1919Bi ex-decay energy and lifetime w"ith literature values. 5 } Assignment of the 199Fr
was based on the observation of the ER_199Fr_195g At
correlations with a low background and the agreementof the 1959 At a-decay energy and lifetime with the measured values in this experiment.
Table 1. The a-decay properties measured in present experiment.
Nuclide195m At
191mBi1959 At
1919Bi
199Fr

Present
Eo (keV) T l / 2 (ms)6960±20385~~i6869±20156~~b7091±40
144~i!
6316±2013±2 s
12~!O7655±40

Literature
Eo (keV) Tl/2 (ms)6876±5 5)150±156 )6311±5 5 )12±1 S5)'." ;:
~

'~\'

'

.

6900 '-'--L....l...-'--'--'-'--'-'-.1-.J.-.L--L--'-'-,-,-.L.-L-J
6600
6700
6800
6900
7000

Ecx2[keV]
Fig. 1. The ER-a1-a2 correlations . 6.tl ~ 1.0 s, 6.t2 ~0.5 s. Group A: ER_l!)5m At_ 191m Bi.

References
1) W. Treytl and K. Valli: Nucl. Phys. A 97, 405 (1967).
2) M. Leino: Ph. D. thesis, Dept. of Phys., Univ. of
Helsinki (1983).
3) For example, see Table of Isotopes, 8th edition, Vol. 2,edited by R. B. Firestone and V. S. Shirley (John Wiley& Sons. Inc. , 1996).
4) K. Morita et al.: Nucl. Instrum. Methods Phys. Res. B
70, 220 (1992).
5) E. Coenen et al.: Phys. Rev. Lett. 54, 1783 (1985).
6) M. Leino. et al. : Phys. Rev. C 24, 2370 (1981).
57

RIKEN Accel. Prog. Rep. 32 (1999)

Experimental Result of the 40 Ar + 238U Fusion Reaction
Y. Tagaya, K. Morita, K. Uchiyama, T. Ariga, T. Hirakawa, K. Suda,
M. Okada, K. Ohta, T. Ishizuka, K. Sueki,*l T. Motobayashi,
H. Miyatake, S. Jeong, and T. Nomura*2[NUCLEAR REACTION, 238U(40 Ar, a2n), 272Hs, Deformed closed shell, Gas-filled recoil separator]
Existence of the deformed closed shell near N = 162
was predicted in the shell model calculation. 1) Although the a-decay energies (Ea) near N = 162 2) havebeen measured a few times, more data beyond N = 162
are necessary to prove the existence of such shell. We
have therefore performed an experiment to produce
272Hs (Z = 108) from the 238U(40 Ar, a2n) reaction
and to determine the Ea and the half-life (T 1/2) of
272Hs. The same reaction experiment was performed
previously,3) but the result was ambiguous due to thepoor statistics. In the current setup, both the beam
intensity and the position resolution of the detector
have been improved significantly.
The 0.5 mg/cm 2 thick U0 3 target material waselectro-deposited on the aluminum foils, and thesepieces of target were mounted on a disk. The disk
was rotated at 10 rps for the irradiation of the pulsed
40 Ar beam (duty factor 0.7) from the RIKEN Ring
Cyclotron. Bombarding energies at the half thicknessof the target were 209 ± 3 MeV and 201 ± 3 MeV.
Beam intensity was 0.3 pJ-LA on average, and the total
dose was 9.0 x 1034 cm- 2 for 209 MeV bombardment .
They were 0.4 pJ-LA and 4.0 x 1035 cm- 2 respectively
for 201 MeV bombardment. The evaporation residue
was separated from the primary beam by using thegas-filled recoil separator (GARIS).
Two dimensional position sensitive detector (PSD)
was placed at the focal plane, and the energy, position and absolute time of all events were measured at
the place. Another silicon detector was placed behind
the PSD to reduce the event triggers originated fromthe arrivals of light particles. A micro-channel-plate(MCP) assembly was placed 70 cm upstream of the
PSD , and its signals were used for the time-of-flightmeasurement between the MCP and PSD and for thediscrimination of arrival events from decay events. The
beam energy, intensity, and status of the target weremonitored by measuring the elastically scattered projectiles with a silicon detector.
Firstly, the correlations consisting of the arrival of
the evaporation residue (ER) and the first a-decay (aI ,272Hs) were searched on the conditions that the timedifference between ER and al (~t) is smaller than 2 s,
the Ea is between 9.0 and 9.5 MeV, the horizontal position difference (Llx) is smaller than 320 J-Lm, and thevertical one (~y) is smaller than 500 J-Lm. Then, one
correlation was found, whose Ea was 9352 ± 40 keY
*1
*2

58

Tokyo Metropolitan University
KEK Tanashi

and ~t was 40 ms. The al event of this correlation was
during the beam-on period in 201 MeV bombardment.
Secondly, all the events following the above correlation were searched for the second a-decay (a2' 268Sg)
and for the spontaneous fission (SF, 264Rf), within thesame position gate as ER-a 1. However, no correlation
was found . Observed Ea and Llt were consistent withthe properties of two correlations in the previous experiment (Eo = 9353 keY, ~t = 16 ms; Ea = 9376 keY,
Llt = 47 ms 3}) which formed a short half-life group.
Other three candidates (Ea = 9347 ke V, ~ t = 949 ms;
Ea = 9357 keY, Llt = 949 ms; Ea = 9401 keY,
Llt = 953 ms 3 )) which formed a long half-life groupwere also observed in the previous experiment, but
no corresponding correlation was found in present experiment. If the observed event comes from 272Hs, theEa sytematics suggests a manifestation of the shell effect (Fig. 1). The experimental cross-section of theobserved event was calculated to be 0.1 nb assumingthat the transmission efficiency of the GARIS was 5%.
12000

I

I

I

Z = 110
-

I-

11000

~

Z = 108(Hs) \~1:5

r-Z= 10~

i:,
10000

1-

272
lOS Hs\+. ~ '- 0 /

900 0

150

~

?
-

I

"I

I

155

160

165

170

Neutron Number

Fig. 1. Eo, systematics for heavy elements. The data
shown by square markers were taken from the eariler
works. The datum of cross marker is from present work.

References
1) Z. Patyk and A. Sobiczewski: Nucl. Phys. A 533, 132(1991).
2) For example, Yu. A. Lazerev et al.: Phys. Rev . C 54,
620 (1996).
3) T. Nomura et al.: RIKEN Int. Workshop on HeavyIon Reactions with Neutron-Rich Beams, Wako, p. 269(1993).

RIKEN Accel. Prog. Rep. 32 (1999)

Plan for Lifetime Measurements of Excited States Using the Recoil
Decay Tagging Technique with Gas-Filled Recoil Separator
K. Uchiyama, K. Morita, K. Furuno, and Y. Tagaya[Lifetime measurement, Recoil decay tagging, Gas-filled recoil separator]
We propose in-beam ,-ray spectroscopy experiments
using the recoil decay tagging 1) and also lifetime measurements of excited states with RIKEN GAs-filled Recoil Isotope Separator (GARIS). The main purpose is
to study the nuclear structure of the low-lying statesin neutron deficient isotopes near and beyond the leadregion. The study of nuclear structure in this region is quite challenging. For instance, Dracoulis etal. reported the irregular yrast sequence in 174Pt. 2)
They had to identify the nuclides based on ,-X coincidence informations. The recoil decay tagging technique makes isotope identifications easier. So it will become possible to use more complex reaction channels
which are needed to produce more neutron deficientisotopes by fusion-evaporation reaction. The recoil decay tagging is suitable for systematic study of this irregular sequence. This is the reason why we propose
the recoil decay tagging experiments using GARIS.
In addition to the energy level schemes, the reduced
transition probability deduced from the lifetime of excited states is indispensable especially for studying
anomalous behavior of the low-lying states like mentioned above. In the Ba isotopes, for an example ofthe extreme case, pairwise proton transfer causes toenhance the B(E2 : ot ~ 2t) values of the isotopes
in mid-shell region without a concomitant change inthe energies of low-lying states. 3 ) An intrusion of the
proton core orbit into valence shells is concerned withthis phenomenon. So it is impossible to indicate thiswithout an information of reduced transition probability. More complex phenomena are expected nearand beyond the lead region. Therefore, it is necessary
to measure not only ,-ray spectra but also lifetimes
of excited states. Fortunately, the lifetime measurements can be performed using almost the same setup
as of the recoil decay tagging, in principle. We will
briefly describe here about the concept of this lifetime
measurement combined with the recoil decay tagging
technique.
Our plan of lifetime measurements is a modified recoil distance method, like the differential plunger proposed by Dewald et a1. 4) The conventional recoil distance method is performed using target and stopper,
and the decay curves are determined by the following
relation:(1)
where D is the distance between target and stopper,I s and Iu are the Doppler shifted and unshifted peakintensities, respectively. The stopper should be thickenough to stop the recoiling nuclei because the Doppler
unshifted peak intensity is needed to make the decay
curves. In the case of using the mass separator, thestopper must be replaced by the "retardation" foil for
introducing the recoiling nuclei into the mass separator. A schematic drawing of the setup is shown in
Fig. 1. The recoiling nuclei are separated from the primary beam by the GARIS, and then are implanted intoa two dimensional position sensitive silicon detector(PSD). The implantation of the evaporation residues
and their a decays are detected by this PSD. The timeof flight measurement is additionally performed using
a micro-channel plate assembly (MCP) and the PSD.
The ,-ray detectors around the target are used to measure both the fully Doppler shifted and the reduced
Doppler shifted, rays which are in coincidence with
the implantation signal of the PSD. Distance between
the target and the retardation foil can be varied bymoving the position of the retardation foil to determine decay curves of the excited states.
y-ray
detectors Target

GARIS

(:pI

o

PSD

MCP

Primary beam

III

TOF

•

Retardation foil

Fig. 1. Schematic drawing of a setup for lifetime measurements using the recoil decay tagging with the GARIS.

The main purpose of using the retardation foil isto determine the fully Doppler shifted peak. Therefore the retardation foil must be thin enough for therecoiling nuclei to pass through and to make the signal in the focal plane detector. But it must be thickenough to reduce the velocity of the recoiling nuclei.
For instance, the schematic ,-ray spectra of the fully
Doppler shifted peak and the reduced Doppler shiftedpeak of 2t ~ ot transition in 174Pt, produced by thereaction 11 5 In (63 Cu, 4n), are shown in Figs. 2 and 3.
These spectra are the results of drastically simplified
Monte Carlo simulation, where assumed are the following conditions: the distance between the target and theretardation foil is 200 {Lm, the retardation foil is a gold
one, the energy of the, ray is 394.2 keY, the detector
angle is 150 with respect to the beam axis, the lifetime
059140000
120000100000
C/)

1:

80000

0

60000

:J

0

40000
20000
0
740

750

760

770

780

790

800

ChannelFig. 2. A spectrum consisting of the fully Doppler shiftedpeak and the reduced Doppler shifted peak of-+transition in 174pt. The thickness of the retardation
foil was 2 mg/cm 2 • Other parameters are described in
the text.

2t ot

retardation foil. Figure 3 shows the schematic spectrum when a 4 mg/cm 2 thick gold foil was used as aretardation foil. In this case, it is possible to divide
it into two peaks. The kinetic energy of the recoiling
nuclei is about 48 MeV in the laboratory frame after
passing through the 4 mg/cm 2 retardation foil. Thisvalue 48 Me V is enough high.
In present case, ! decay occurs not only near the target position but also inside the GARIS. So the decay
curve R(D) cannot be determined by Eq. (1) because
the total intensity, that is the denominator of Eq. (1),cannot be determined correctly. This situation is similar to the conventional recoil distance measurementwith inverse reaction made by H. Emling et al.7) In
their case , it is difficult to determine the intensity of
the unshifted peak due to the long slow-down time inthe stopper foil. So, they used the equivalent relationship:

R(D) = 1 _ 18(D) .

18(00)

140000fully shifted
120000reduced shifted~/'

100000
C/)

1:
:J
0

0

80000
60000

20000
0
740

750

760

770

780

790

800

ChannelFig. 3. A spectrum consisting of the fully Doppler shifted-+peak and the reduced Doppler shifted peak oftransition in 174pt. The thickness of the retardation foil
was 4 mg/cm 2 . Other parameters are same as Fig. 2.

2t ot

is 28.1 ps estimated by empirical relations,3,5) and theenergy of recoiling nuclei is 103. 7 MeV in the laboratory frame. The energy loss in the retardation foil was
estimated using the stopping-power table 6 ) and somecorrections; however, the energy straggling, multiple
scattering in foils etc., were not included in these simulation. Figure 2 shows the schematic spectrum whena 2 mg/cm 2 thick gold foil was used as the retardation
foil. Obviously, it is impossible to divide the spectrum into two peaks when the thinner foil is used as a

60

Consequently, in present case, the decay curve R(D)can be determined simply by the fully Doppler shiftedcomponent If8(D) and by using the following relationship:

R(D) = 1 _ If8(D)If8(00) ,

40000

(2)

(3)

where D is the distance between the target and theretardation foil. The normalization to If 8 (D) at every
distance can be performed using the total number ofthe recoiling nuclei, which can be deduced from the 0'decay spectrum detected by the PSD. We should mention that the value of If8(00) can be measured fromthe setting without a retardation foil. This is just thenormal recoil decay tagging setup. More detail on the
setup, method of data analysis, and so on are underdiscussion.
References
1) K. Helariutta et al.: Phys. Rev. C 54 , R2799 (1996) .
2) G. D. Dracoulis et al.: Phys. Rev. C 44 , R1246 (1991).
3) M. Sugita et al.: Phys. Lett. B 440, 239 (1998).
4) A. Dewald et al.: Z. Phys. A 334, 163 (1989).
5) S. Raman et al.: Phys. Rev. C 37, 805 (1988).
6) L. C. Northcliffe and R. F. Schilling: Nucl. Data Tables
A 7, 233 (1970).
7) H. Emling et al.: Phys. Lett. B 98, 169 (1981).

RIKEN Accel. Prog. Rep. 32 (1999)

Reaction Products from the 208Pb + 208Pb Reaction
at 15A MeV
K. Yoshida, M. Shimooka, R . Wad a , T. Nakagawa, K. Nakagawa, I. Tanihata,
Y. Aoki, J. Kasagi, and W . Q. Shen*[208Pb + 208Pb, 15A MeV, Fission]
The energies and velocities of reaction products havebeen measured for the 208Pb + 208Pb reaction at 15A
Me V to investigate the formation of a very heavy compound nucleus. Due to the strong Coulomb repulsion,it has been thought that the formation of a compound
nucleus is strongly hindered in the collision between
heavy nuclei such as 208Pb + 208Pb. However, recent theoretical calculations suggest that a heavy compound nucleus can be formed in heavy nucleus-nucleus
collision at sufficiently high incident energies to overcome the strong Coulomb repulsion. Such a heavy
compound nucleus, if it is formed, will decay to plural
fragments by fission. In the experiment, we focusedon the detection of all the fragments from a ternary
fission of the heavy compound nucleus, since the fragments from usual binary fission are known to distributein space similar to the reaction products of a deep inelastic reaction.
The experiment was performed at the RIKEN Ring
Cyclotron. 208Pb beams with an energy of 15A MeV
was bombarded on a 99.9% enriched 208Pb foil of
1 mg/cm2 in thickness backed with 20 J.Lg/cm 2 collodion. Fission fragments were detected with the large
PPAC/IC chamber l ) which covered 25-75 laboratory
angles around the beam axis. The chamber is divided azimuthally into 12 identical units with a minimum dead space in between. A backward hemispherewas covered with BaF 2 phoswich detectors 2) to detectcharged particles as well as ,-rays.
Figure 1 shows the correlation of relative azimuthal
angles among the three fragments detected by the
PPAC/IC chamber. As seen, most events have an
asymmetric character: one of the angle is about 60 0
and the others are about 150 0 • In these events, thetwo fragments with a small folding angle have a strong
correlation in their velocities. This suggests that theevents come from the fission of projectile or target nuclei after the deep inelastic scattering.

180
160
140

en
Q)

~
('f)

C'l

-e-

120
100
80
60
40
20
20

40

60

80 100 120 140 160 180<1>12 (deg)Fig. 1. Correlation of relative azimuthal angles between
two fragments from the three-fragment events in the
208Pb + 208Pb reaction at 15A MeV. The definition of
the relative azimuthal angles is schematically shown in
inset.

0

Yield of the symmetric event, of which all three folding angles are nearly 120 0 , is about 1% of the total
three-fragments events. There is no strong correlationin velocities of these fragments. This can be interpreted as a signature of the simultaneous break up of
three fragments. Analysis of the deduction of massof the fragments and analysis of the charged particle
spectra are now in progress.
References
1) K. Yoshida et al.: RIKEN Accel. Prog. Rep. 31, 165(1998).

2) Y. Futami et al.: Nucl. Instrum. Methods Phys. Res. A
329 , 513 (1993).

Shanghai Institute of Nuclear Research, Chinese Academyof Science, Shanghai, China

61

RIKEN Accel. Prog. Rep. 32 (1999)

Measurement of the Cross Sections and the Vector and Tensor
Analyzing Powers for d-p Elastic Scattering at Ed == 270 Me V
K. Sekiguchi, 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, T. Niizeki, and H. Sakai[NUCLEAR REACTIONS, 1 H(J: d), Ed = 270 MeV measured: O"(B), Ay(B) , Ayy((;}), Axx(B), Axz((;})]
The measurement of the cross sections and the vector and tensor analyzing powers A y , A yy , A xx , Axz
for the deu teron-proton (d-p) elastic scattering at
270 MeV has been reported by Sakamoto et al.l) Theirresults are shown in Figs. 1 and 2 by the open squares.
The solid curves are the three-body Faddeev calculations which take into account the NN interactionsof j ::; 4. Although the fit of the analyzing powers
is generally good, the calculated differential cross sections are smaller by 30% than the observed values at
the angles where the differential cross sections become
minimum. Recently it is pointed out that this discrepancy might be due to the effect of three nucleon force(3NF).2,3) Since the previous measurement covers only
the limited angular range Bc .rn . = 57.0°-137.8°, we extended the measurement to a wide angular range.
The differential cross sections and the vector andtensor analyzing powers A y , A yy , A xx , A xz were measured at Ed = 270 MeV for the forward angles 10°-60°
and for the backward angles 125°- 180°. The CH 2 target with a thickness of 46.7 mg/cm 2 was bombarded

0 .5

0 .0 P - - -..........----.l<----"'I-0.5

0.0 ~-------jir-l

-0.5

Ayy

1.0

1.0

0.5

0.5

0 .0

0 .0 1 - - " - - - - - - - - - - \

0

50

100

ec .m . [deg]

150

o

50

100

150

ec .m . [deg]Fig. 1. Ay, Ayy, A xx , A xz for the d-p elastic scattering
at E~ab = 270 Me V. The solid circles are the resultsof this experiment and the open squares are those ofRef. 1. The solid curves are the theoretical predictionsof the Faddeev calculation taking into account NN partial waves j ~ 4. The dashed lines are theoretical predictions including the effect of 3NF.
62

0 .6

50

100

150

8 c .m ,[deg]Fig. 2. The differential cross sections for the d-p elastic
scattering at E~a b = 270 MeV. The solid circles are
the results of this experiment and the open squares arethose of Ref. 1. The solid and dashed curves are thesame as Fig. 1.
by a polarized deuteron beam and either scattereddeuterons or protons were detected by the spectrograph SMART depending on the scattering angle.
Present results of the analysis are shown with solid
circles in Figs. 1 and 2. The errors are statistical ones
only and their sizes are smaller than the symbols. Since
the two independent measurements provide almost thesame values in the overlapping region , the systematic
errors seem to be small. The dashed curves in Figs. 1
and 2 are the calculations by Wit ala et al. 2,4) whichtake into account the effect of 3NF. Note that the
Coulomb interaction is not included in this calculation. The calculation with 3NF shows an excellent fit
over the whole observed angular range. Thus the discrepancy in the cross section minimum seems to beaccounted for by 3NF. The observed vector analyzing
powers Ay are also in good agreement with the calculations with 3NF. However the agreements in the tensor
analyzing powers Ayy and A xx are rather poor.
Further analysis for the very forward angles are in
progress together with those for the Axz data.
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.

RIKEN Accel. Prog. Rep. 32 (1999)

The 3He(J,p)4He Reaction at Ed = 140 and 270 MeV
T. Uesaka, H. Okamura, Y. Satou, T. Ohnishi, K. Sekiguchi, K. Yakou, S. Sakoda,
N. Sakamoto, T. Wakasa, K. S. Itoh, K. Suda, and H. Sakai[3He(d,p)4He, Ed = 140, 270 MeV, Measured analyzing powers]
The high momentum component of deuteron is offundamental interest because it is directly connected tothe interaction between two bound nucleons in specificquantum states. The 3He(d,p)4He reaction at intermediate energy is considered to provide a way to study thehigh momentum component of deuteron D-state wave
function.!) A prior study was made at Blab = 4° byusing a 270 Me V polarized deuteron beam at RARF.
The results of this experiment, however, show polarization observables in significant disagreement with both
PWBA and DWBA. For the purpose of a detailed theoretical investigation regarding the reaction mechanismof the 3He(J: p )4He reaction, systematic study is necessary, such as measurement of angular distribution andenergy dependence of polarization observables and differential cross section is necessary.
We have measured the angular distributions of differential cross section, vector and tensor analyzing
powers for the 3He(J:p)4He reaction at Ed = 140 and
270 MeV.
The new cryogenic-gas-target was constructed forthis experiment. The schematic view of the target isshown in Fig. 1. 3He gas was enclose in a copper container which is contacted to a refrigerator. The target
dimensions were 13 mm (20 mm) wide, 15 mm (20 mm)
high and 20 mm (10 mm) thick in the case of 270 MeV(140 MeV) measurement. Entrance and exit windows
were 6 J.tm thick Habar foils. The gas container andthe second stage of the refrigerator were shaded fromthermal radiation of the circumstances with a SUS pipe
which is attached to the first stage (77 K) of the refrigerator. The SUS pipe was also wrapped with superinsulator foils. Temperature of the target was measured by using a diode thermo-sensor and found to beabout 11 K throughout the experiment. The densityof the 3He gas reached 6.6 x 10 20 cm- 3 (6.7 mg/cm 2 ).
A polarized deuteron beam from the Ring Cyclotron
was used to bombard the target. The scattered protons were momentum-analyzed in a magnetic spectrograph SMART and detected at the second focal plane.
The detector system consisted of an eight-plane multiwire drift chamber and three plastic scintillators. Obtained energy spectrum is shown in Fig. 2. The peakat Ex = 0 MeV is from the 3He. Other peaks at higher
excitation energies are from Habar foils.
The further analysis is in progress.

6000

>'
QJ

..'.<:a':::'4000

...,
til

C

;::l

diode themo-sensor

SUS pipeo~"d 2000

3Hegas

/

Q)

:;::
-5

o

5

10

E % [MeV]oFig. 2. Excitation energy spectrum for the 3He(d,p)4He
reaction at Ed = 270 Me V.

1st stage of refrigerator (77K)
2nd stage of refrigerator (11K)
SOmm

thermocouple

References
1) T . Uesaka et al.: Nucl. Instrum. Methods Phys. Res. A

Fig. 1. Schematic view of the cryogenic gas target.

402, 212 (1998).

63

RIKEN Accel. Prog . Rep. 32 (1999)

Spectroscopy of IIBe via IIB(d, 2He)IIBe Reactionat Ed == 270 MeV
T. Ohnishi, H. Sakai, H. Okamura, T. Niizeki, K. S. Itoh , T . Uesaka, Y. Satou,
K. Sekiguchi, K. Yakou, S. Fukusaka, N. Sakamoto, and H. Ohnuma
NUCLEAR REACTION: 11B(polarized d, 2He)11Be at[ Ed = 270 MeV; Measured (J, A y , A yy , and Axx; Neutron halo
The neutron halo nucleus 11 Be has been studied bymany experiments and theoretics. Particularly, theground state is interesting, since it has a spin andparity of ~ + due to the inversion the 1s- and Op-shellorbits. The effect of the neutron halo is expected toappear in the dipole transition. From the theoretical
calculation for the spin- and isospin-flip dipole transition, the effects of the neutron halo are as follows 1):
Firstly, the peak position of the dipole transition withhalo appears at an excitation energy around 10 MeV. It
is smaller than that without halo. This is because thesmallness of the gap between 1s- and Op-shells. Secondly, the strength of the dipole transition is enhanced.
This is because the operator for the dipole transition
has a radial part, r. Therefore, the matrix elements
involving a halo have a better overlap at a large radius owing to the large mean square radius comparedto that of the core.
In the present measurement, we have studied 11 Be
excited states by using the 11 B(d, 2He)11 Be reaction at
270 MeV. 2He indicates proton-proton system coupled
to the singlet S-state. The (d, 2He) reaction excites
exclusively spin- and isospin-flip excitation: GamowTeller (GT) type transitions (~L = 0), and spin-flip
dipole (SD) transitions (~L = 1), and so on. The
spectroscopic application of the (d, 2He) reaction at intermediate energy is well tested by the 12C(d, 2He)12B
measurement. 2) The measurement using the same reaction was performed at 70 MeV.3) Though the effectsof the neutron halo were measured, some ambiguity ofthe deduction of ~L remained. Thus, to deduce ~L
more clearly, we have measured the 11 B(d, 2He)11 Be
reaction at angles where the value of the cross section
for the dipole transition becomes largest.
The present measurement was performed at RIKEN
Accelerator Research Facility by using the polarized
deuteron. The thickness of the 11 B self-supporting
target was 18.9 mg/cm 2. The contribution of thecontamination was negligibly small. The scattered
two protons were momentum analyzed by the spectrograph, SMART, and were detected by a multi-wiredrift-chamber and a scintillator hodoscope located at
the first focal plane. The angular distributions of thedifferential cross section and the analyzing powers,
A y , A yy , and Axx were measured in the range eL =0°-16°. The typical spectra of the differential crosssection and the tensor analyzing power Axx are shownin Fig. 1.
64

1

>
Q)

~
~
1'1.1

...........

.0

8

'-'

c~

o.

~ 0.020~ 0.015

o

5

10

15

20

u Be Excitation Energy (MeV)
Fig. 1. (a) Spectrum of the differential cross section at
Oem = 0°-2° , (b) Oem = 4°_6°, and (c)Oem = 12°-14°.
(d) Spectrum of the tensor analyzing power Axx at
Oem = 7°- 10°.

In Fig. 1 (a)- (c), several GT transitions are clearlyseen at low excited energy region. In addition, a newpeak which is considered to be GT transition is foundat E x = 8.4 MeV.
The broad bump appears at around Ex = 10 MeV.
Since the broad bump becomes larger at the finite angle, it is considered to be consisted of the spin-dipole
transitions and higher ~L transitions . Further analysis is in progress.
Finally, we thank Bill Lozowski at the Indiana U niversity Cyclotron Facility for making the 11 B target
for us.
References
1) T. Hoshino et al.: Nucl. Phys. A 523, 228 (1991).
2) H. Okamura et al.: Phys. Lett. B 345, 1 (1995).
3) H. Sakai et al.: Phys. Lett. B 302, 7 (1993).

RIKEN Accel. Prog. Rep. 32 (1999)

Measurement of Elastic and Inelastic Scattering of Polarized
Deuterons from 28Si at 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. S. Itoh, T. Ichihara, T. Niizeki, and K . Hatanaka[NUCLEAR REACTION, 28Si(polarized d, d') Ed = 270 MeV; measured a(B), Ay(B), Ayy(B)]
Optical model potentials determined from elastic
scattering are often necessary inputs for the calculation of inelastic scattering. At intermediate energies(E/ A > 100 MeV) deuteron-nucleus elastic scattering
data, however, are very scarce and no global opticalmodel potentials are available at present. In order toobtain optical potential parameters, we have measured
the elastic scattering of polarized deuterons from 28Si
at Ed = 270 MeV. Since 28Si is a strongly deformed
nucleus with strong excitation of the first 2+ state, thechannel coupling could be important. The data for the
inelastic excitation to the 2+ level were also acquired.
The measurements were performed in the E4 experimental room using a 270 MeV polarized deuteron beamfrom the RIKEN Ring Cyclotron, as part of an experiment devoted to the determination of the deuteronspin-flip probabilities, 8 1 and 8 2, in the 28Si(d~ d!)reaction. 1 )In Fig. 1, measured angular distributions of the crosssection a, and ·analyzing powers, Ay and A yy , for theelastic scattering are shown. The solid lines in Fig. 1
are the results of the optical model (OM) fits. The
OM parameters in the notat ion of Ref. 2 were obtained from the simultaneous analysis of a , Ay andAyy by using the code ECIS by Rayna1. 3 ) The data are
well reproduced by the OM calculation. In the present
OM analysis an imaginary central potential having a
Wood-Saxon term (a volume absorption term) as well
as a derivative of the WS term (a surface absorptionterm) in the ratio of about 14 : 1 was required. This isin disagreement with the extrapolation from the lower
energy analysis,2) in which the surface imaginary term
was indicated to decrease as a Gaussian function of theform Wexp[-(E/IOO)2], where E is the c.m. kinetic
energy.
In Fig. 2, data for the inelastic scattering to the first2+ state are displayed. The solid lines in Fig. 2 are
the results of the coupled-channel (CC) macroscopic
calculation, where the coupling between the ground 0+
and the first 2+ states were taken into account under
the framework of the rotational model which assumes
an oblate deformation for all the potential terms. The
agreements between data and theoretical curves are
satisfactory. In order to obtain simultaneous fits to all
the data, the OM parameters had to be varied fromoriginal ones. The most significant of these was thesurface imaginary potential, which decreased by about
80%. This may indicate that the surface absorption
term required in the present OM analysis is responsible
for the absorption due to the 0+-2+ channel coupling,
and that it no longer plays an important role in the CC
calculation in which the channel coupling is explicitly
taken into account.

1. 00

2· 5i ( d. d' )( 2 +; 1. 78MeV)

0.75

E.=270 MeV

0.50
0.25
0.00
1.00
0.75

,--.....
L
(f)

0.25

0.75

E.= 270 MeV

~
.D

0.00

0.50
0.25

E 10 2o0.00"'---"

C

0.50

1.00

2. 5 ;( d.d)(O+:gnd .)

10 4

1.00

E
U 100

0.75
050

V
~

0.25

~ 10- 2

10

B cm .

20

30

(deg)

40

0

10

20

30

40

e c.m . (deg)Fig. 2. Data for the 28Si(cI: d')(2+ ; 1.78 MeV) reaction at
Ed=270 Me V. Solid lines are results of the CC calculation.

0.00

o

10

B em.

20

30

(deg)

40

0

10

20

30

40

e em. (deg)Fig. 1. Deuteron elastic scattering data on 28 Si at Ed =270 MeV. Solid lines are results of the OM calculations.

References
1) Y. Satou et al.: RIKEN Accel. Prog. Rep . 31,62 (1998).
2) W. W . Daehnick et al.: Phys. Rev. C 21, 2253 (1980).
3) J. Raynal: Computer code ECIS, IAEA-SMR-8/8, p . 75
(1972).

65

RIKEN Accel. Prog. Rep . 32 (1999)

Gamow-Teller Strength of 28Si, 32S, and 34 S(d, 2He)
K. S. Itoh, T. Niizeki, T. Ichihara, H. Sakai, H. Okamura, S. Ishida, N. Sakamoto,
T. Uesaka, Y. Satou, T. Ohnishi, Y. Tajima, G , Yokoyama, K. Sekiguchi,
K. Yakou, S. Fukusaka, H. Ohnuma, and H. Orihara[NUCLEAR REACTION (d, 2He), GT (3 decay]
We present preliminary (d, 2He) reaction spectra on
the target of 28Si,32S, and 34S at a small angle. We
make a comparison of the (d, 2He) spectra with theGamow-Teller strength from (p , n) reaction for N = Z
8Si, 32S) nuclei. Then, we compare these spactrawith shell-model calculations for the N = Z + 2 4 S)
as well as N = Z nuclei.
The experiment was performed using a 270 MeV
deuteron beam available from RIKEN Ring Cyclotron,a large solid-angle and wide momentum-acceptancemagnetic spectrometer system, SMART. The 2He nucleus was detected by a pair of Multi-Wire Drift
Chambers(MWDC).1) Since 2He is at unbound state,
the pairs of two protons whose relative energy is within
1.0 MeV were actually detected. Targets were selfsupporting foils: 25.5 mg/ cm 2 thick natSi, 38 mg/cm 2
thick nats, and 37 mg/cm 2 thick 34S enriched to 99.4%.
For N = Z nuclei the GT+ strength should be equivalent to the GT _ strength. Actually, the (d , 2He) spectra on both of 28Si and 32S seem to be in good agreement with the (p, n) data as shown in Fig. 1. 2,3)Comparisons of experimental data with shell-model
calculation is shown in Fig. 2. Shell-model calculations

e

e

1.5

50 0

(a)
1.2

400

;;>
0

~ 300

0.9 f=:'

D

0

~

"'Cil

§ 200

O.Sa:;

0

U

0.3

100
0

0
5

0

1.5

SOO

(b)

500

;;>
~ 400

f=:'

N

D

~ 300

~

c

al

;:l

8 200

0.5

100
0
5

0

1.5

250

shell-model
2 00~

Bth(GT)

(C)

I

1.2

0

400

;;>

34S(d,2He)34p
Ed=270MeV
O-l.Odeg.

~ 150

28S i (p,n)28p
E p ",135MeVI•

Bpn(GnI0~c;:l 100

(a)
1.2

D

::E'

O.sal

U

50

0.9 f=:'

0

0.9~

0

0

~ 3 0010

Ex(MeV)

;;>
500

10

Ex(MeV)D~ 2 00

'2'

o

O.S:

0

U

5
Ex(MeV)

10100
0Fig. 2. Comparison of the (d, 2He) excitation-energy spectra with the GT strengths of shell-model calculation by
OXBASH on (a) 28Si, (b) 32S, and (c) 34S.

0
0

5

10

Ex(MeV)
600
500

;;>

~ 40 0N

1.5

32S(p,n)3 2Cl
E p =135MeV

(b)

I •

r::;'

D

~ 30 0

~

'i::
;:l

Q.

co

8 200

0.5

100
0
0

5

10

0

Ex(MeV)

Fig. l. Spectra (a) and (b) are for comparison of the (d,2He) with (p, n) reactions on 28Si and 32S , respectively.
Bpn(GT) from (p, n) experiments at IUCF. 2,3 )66

can reproduce well the (d, 2He) spectra on 28Si, 32S
and 34S. In Fig. 2(c), the spectrum of (d, 2He) on 34S(N = Z + 2 nucleus) agrees well with the shell-model
calculation by OXBASH code. Therefore, present data
indicates that the (d, 2He) reaction is a useful tool forthe study of GT strength in the N 2 Z nuclei.
References
1) H. Okamura et al.: Nucl. Instrum. Methods Phys. Res.
A 406, 78 (1998).
2) B. D. Anderson et al.: Phys. Rev. C 43, 50 (1991) .
3) B . D. Anderson et al.: Phys. Rev. C 36 , 2195 (1987).

RIKEN Accel. Prog. Rep. 32 (1999)

Transverse Momentum Distribution of Fragments
in Reaction 40 Ar + 9Be
S. Momota, M. Notani, N. Fukuda, H. Iwasaki , K. Yoneda, H. Ogawa, N. Aoi, S. Ito, T. Teranishi,
N. Inabe, T. Kubo, T. Nakamura, H. Okuno, A. Ozawa, H. Sakurai, T. Suzuki,
Y. Watanabe, A. Yoshida, and I. Tanihata
NUCLEAR REACTIONS: 9Be(40 Ar, X ), E(40 Ar) = gOA MeV,
Angular distribution of projectile-like fragments
The momentum distribution of projectile-like fragments provides us information on the nuclear reaction
through which fragments are produced. We have performed a systematic observation of momentum distribution for projectile fragments in the transverse direction.
The projectile fragments were produced by the reaction 9Be(40 Ar, X)AZ at the beam energy E(40 Ar) =gOA MeV. The produced fragments were selected andanalyzed with a RIPS spectrometer. I ) The 40 Ar beam
was deflected by a swinger magnet before the 9Be
target with a recoil angle of Ox, and its acceptanceof RIPS was defined by x-y slits after the 9Be target. The magnetic rigidity of the RIPS was set at
3.71 Tm. The rigidity acceptance of the RIPS was
set at ~BplBp = 1% by a slit at the momentumdispersi ve focal plane (F 1) .
Particle identification (PI) was performed event by
event by measuring the time-of-flight (TOF) and theenergy loss (~E). The detectors for PI, that is two silicon counters (SSD's) and a plastic scintillation counter(PL) were located at the momentum-achromatic focal plane (F2). The TOF of each fragment over the21.3 m of flight-path between the 9Be target and F2
was determined by the PL timing and the RF timingof RIKEN Ring Cyclotron. The ~E was measured
by SSD's. Observed production rate of fragments was
normalized by the beam current monitored by two setsof current-monitor counters, placed on the upstreamand downstream-side of the 9Be target. The profileof the secondary beam at F2 was monitored by theparallel-plate avalanche chamber (PPAC).
Figure 1 shows a typical transverse-momentum distribution of fragments observed. As seen in Fig. 1,
the result is well reproducible by a Gaussian distribution, and its dispersion, O'T can be derived by fitting. Figure 2 shows the (iT obtained as a functionof the longitudinal momentum PL per unit mass. A
correlation between O'T and PL is found in Fig. 2.
In the region PL > 440A Me V I c, (iT is well reproduced by the formulae in Refs. 2 and 3. In the region
PL < 440A 'MeV Ic, O'T increases as PL decreases. This
correlation suggests the contribution of multi-step process in the nuclear reaction at the intermediate beamenergy, E = gOA MeV.

2~1

1
I

I

... ~

1 ~

-

6
4

~\

2

\, -

0.1 ~
6
4

~

2

0.01 -

I

I

I

1-

0

2

4

6

Recoil Angle [deg.]
Fig. 1. Observed angular distribution of 21 0

400...g... Be (9-12), ____ B (11-15)
~

300
U

..........

:>C (14-18), __ N (16-21)-A- 0 (19-23) , __ F (22-26)-4- Ne (25-28) , __ Na (28-31)

200

(lJ

6 100
E-<

0

b
<l

-100
-200 =-----'-_....L...-.&-..I..._-'-----'-_-'----'-_-1..I
360
400
440
480
520
PL per unit mass [MeV lei A]
Fig. 2. Correlation between O'T and PL The contributiohs
from the Fermi momentum of removal nucleons, O'F,2)and from the deflection of projectiles in the field of thetarget nucleus, O'D,3) are subtracted from O'T to derive
6,O'T.

References
1) T. Kubo et al.: Nucl. Instrum. Methods Phys. Res. B
70, 309 (1992).
2) A. S. Goldhaber: Phys. Lett. B 53, 306 (1974).
3) K. van Bibber et al: Phys. Rev. Lett. 43, 840 (1979).

67

RIKEN Accel. Prog. Rep. 32 (1999)

Projectile-like Fragment Momentum Distributions from40 Ar + natTa Reaction at 94A MeV
Z. Liu, M. Notani, H. Sakurai, S. M. Lukyanov, 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,Yu. E. Penionzhkevich, T. Teranishi, Y. X. Watanabe, K. Yoneda, and A. Yoshida
NUCLEAR REACTIONS: natTa(40 Ar, X), EIA = 94 MeV; Measured[ 0° momentum distributions of projectile-like fragments
The production of neutron-rich isotopes by projectile-like fragmentation shows a very strong target
dependence 1 ,2) at intermediate energies. To understand underlying mechanism, parallel momentum distributions of projectile-like fragments (PLFs) includingtransfer reaction products were measured.
The present measurement was performed at RIPS.3)
The 40 Ar beam at 94A MeV bombarded a 17 mgl cm 2
natTa target. The beam current was monitored by twoplastic hodoscopes around the target. RIPS was operated in a double achromatic mode. The angular acceptance was set to be ±12.5 mrad in both horizontal
and vertical direction. At this energy, PLFs were fully
stripped. Particle identification was done unambiguously by a combination of time of flight (TOF), energy
loss (f)..E) and magnetic rigidity (Bp) measurement.
The TOF of a fragment was measured by two plastic
detectors at F2 and F3. The tJ.E was determined by
two 1.1 mm SSD detectors at F3. The Bp was obtained by position information provided by the PPACat F1 together with NMR measurements of the RIPS
dipole fields. Momentum distributions of PLFs were
measured at 30 Bp settings covering a range of 2.533.97 Tm with momentum acceptance tJ.plp = ±0.5%
at lower Bp settings and ±2 .0% at higher Bp settings.
The double differential cross sections d 2 (j I dpdo' around
0° have been deduced by taking into account of PPAC
detection efficiency, and dead time correction. The momentum broadening due to the target thickness is only
0.5% for the fragments very close to the projectile. No
correction for momenta was performed. To avoid too
high count rate on PPACs beam current on the target
was adjusted at every Bp setting. The error in beam
current evaluation is less than 20%.
Momentum distributions have been obtained for 70
individual PLFs of elements ranging from B (Z = 5)
to K (Z = 17). As an example, the momentum distribution of 24Na is shown in Fig. 1, with the bin size
corresponding to tJ.plp = 1.0%. Only stastical error
is shown in Fig. 1. The low-momentum side is wider
than the high-momentum side for every fragment. Except the low-momentum tail, the whole of the distribution is resonably described by an asymmetric Gaussian function with different standard deviations (jh and(jl on the high and low-momentum side, respectively.
The widths (jh obey very well the Goldhaber law4) extracted from "pure" fragmentation at relativistic en68

1

10 1

'"i:'
CIl
""Q
"":>
::s

100

(11

""..0

10- 1

5
c

'tj

<""-

10- 2

0..

'tj

~

10- 3

b

N'tj

10- 4

0 .7

0.8

0.9

1.0

1.1

1.2

P fi P projectile

Fig. 1. Momentum (expressed in momentum per nucleon)
distributions of 24Na from the 40 Ar+natTa reaction (diamond) and the 40 Ar+ 9 Be reaction (square). Momenta
have been normalized to the beam momentum in the
middle of the target. Solid lines represent the fittings
using the asymmetric Gaussian function.

ergies. The best fit to (jhS gives a reduced width of= 85.1 MeV Ic, in agreement with the systematics
in the intermediate energy domain. 5 )Some proton pickup PLFs were observed, of which
momentum distributions have been obtained for
38,39,40 K. Their most probable momenta are lower thanthose of the neighboring nucleon removal PLFs, due
to the dissipative nature of the nucleon transfer process. Interestingly, their most probable momenta and(jh widths can be well explained by simply assumingthat one proton is picked up from the target with amomentum of 270 MeV Ic (Fermi momentum of Ta)
oriented along the beam direction by the Ar PLFs withthe same N. The cross sections of these K isotopes are
1- 2 order of magnitude smaller than those of the Ar
PLFs with the same N.
Comparison was made between the present data andthe Be target data6 ) (40 Ar beam at 90A MeV). Momentum distrubution of 24Na from the Be target reaction is also shown in Fig. 1. Compared with the
Ta target data, the most probable momenta in the
Be target are systemactically shifted downwards andthe widths are wider, especially on the low-momentum
side. These observations indicate that fragments consume more beam energy in the Be target than in the(j0Ta. Thus the prefragments produced in the reaction
with Be target may be hotter, which may hinder the
production yields of very neutron-rich isotopes. On theother hand, it has been suggested that transfer process is responsible for the production of very neutronrich isotopes with heavy targets. 1) Then larger energy
consumption for fragments from Ta target if the reaction mechanism is the same for Be target and Ta
target. However, our result is contrary to this hypothesis. For further investigation on the production mechanism of neutron-rich isotopes, we will study productcross section as a function of Z for a given mass A andcompare them between light and heavy targets.
References
1) D. Guerreau: Nucl. Phys. A 447, 37c (1985).
2) H. Sakurai et al.: Nucl. Phys. A 616, 3Uc (1997) .
3) T. Kubo et al.: Nucl. Instrum. Methods Phys. Res. B
70, 309 (1992).
4) A. S. Goldhaber: Phys. Lett. B 53, 306 (1974).
5) V. Borrel et al.: Z. Phys. A 324, 205 (1986).
6) M. Notani: private communication.

69

RIKEN Accel. Prog. Rep. 32 (1999)

Measurement of Fusion Cross Section of Neutron-Skin Nucleus 6He
Y. X. Watanabe, N. Aoi, N. Fukuda, T. Fukuda, M. Hirai, N. Imai, M. Ishihara, H. Iwasaki,
Y. Mizoi, M. Notani, H. Ogawa, H. Sakurai, Y. Watanabe, K. Yoneda, and A. Yoshida[NUCLEAR REACTION 40Ar(6He,X), ECM = 3- 15 MeV]
In the energy region near and below the Coulomb
barrier, the fusion cross section of a neutron-rich nucleus is expected to be strongly enhanced as compared
to a usual nucleus due to the extraordinary structureof the neutron-rich nucleus. 1 ,2) We have measured thefusion cross section between a neutron skin nucleus 6He
and 40 Ar in the vicinity of the Coulomb barrier withRIPS at the RIKEN cyclotron facility. We report theexperiment and the present status of the analysis.
A 9Be production target with 1656 mg/cm 2 thickness was bombarded with a 11 B beam. The energy
and intensity of the primary beam were 70 MeV lu and
200 pnA, respectively. The 6He beam was separated
by RIPS from other reaction fragments. The secondary
beam was decelerated with an aluminum degrader, andthe beam energies in the center of mass system at thereaction were from 3 Me V to 15 MeV. The energy of
6He was determined event by event by measuring atime of flight between two plastic scintillators placed
at intervals of 5.3 m. The 6He beam was led into a
multiple-sampling and tracking proportional chamber(MSTPC),3) which had been developed by our group
to detect a three-dimensional image of several tracks
of charged particles and to detect the energy loss of
those particles along their tracks. The MSTPC was
filled with a mixed gas (argon:98%, methane:2%) at
100 torr pressure, where the gas acted as a target aswell as a detection gas. The positions and energy lossesof charged particles were sampled by 64 cathode plates(called PAD's) aligned at 11 mm intervals along thebeam line.
Figures 1 and 2 show an example of the energy
losses for a fusion event and an elastic scattering event,

0.35

0.3
0.25

~
~ 0.2
~
i!0.15
JC~'CI 0.1
0.05

00

5

10

15

20

25

30

35

40

45

PAD#

Fig. 2. An example of the energy losses for an elastic
scattering event. Abscissa indicates the PAD number.
Dotted line shows the energy losses in the case of noreaction.

respectively. In both figures, the abscissas indicate the
PAD number, and the ordinates give the energy loss
dE I dx. Figure 3 shows an example of the tracks ofthe projectile and target nuclei in an elastic scattering event. The abscissas indicate the PAD number,and the ordinate of the upper (lower) panel gives thehorizontal (vertical) position. Size of the circles is proportional to the magnitude of the energy loss. We canpick up fusion events out of other reaction events byexamining the tracks and the energy losses. The further analysis is in progress.

8

0 dE/dx-200K.V/PAJ.>

-E4 .
~~

:..

o

0°,

'He

°t············'\:),,g~ §~ -4

He

Ar

a.

-8 ~

20~~~~~~~~~~~~~

0.4

e '6

0.35

_u

0.3

1: 0

:J ';;'12

0.2°°0 'He~09

5 1'0 15 20

,

25
PACt

30 35 41, 4S

Fig. 3. Horizontal and vertical tracks of elastic scattering
event.

0.1 _

0.05

PAD#

Fig. 1. An example of the energy losses for a fusion event.
Abscissa indicates the PAD number. Dotted line showsthe energy losses in the case of no reaction.
70

Ar

4

00

';0.15

~

•
He

,

:I
"CI

~

81'···· .. ·······0
~

~i

_0.25

c
c
~

OdE/dx-200K.V/PAIl

References
1) N. Takigawa et al.: Phys. Rev. C 47, R2470 (1993).
2) J. A. Christley et al.: Nucl. Phys. A 587, 390 (1995).
3) Y. Mizoi et al.: RIKEN. Accel. Prog. Rep. 30, 143(1997) .

RIKEN Accet. Prog. Rep. 32 (1999)

Observation of Excited State in 7He with Unusual Structure
A. A. Korsheninnikov, M. S. Golovkov, A. Ozawa, E. A. Kuzmin, E. Yu. Nikolskii,
K. Yoshida, B. G. Novatskii, A. A. Ogloblin, 1. Tanihata, Zs. Fiilop, K. Kusaka,
K. Morimoto, H. Otsu, H. Petrascu, and F. Tokanai
NUCLEAR REACTIONS, Radioactive nuclear beam, p(8He, d), p(8He, d 6He),[ p(8He, d 4He), p(8He, dn), p(8He, dn 6He), p(8He, dn4He), EI A = 50 MeV
A novel step in the experiments with exotic nuclear
beams, namely, investigation of transfer reactions, isreported. We studied the reaction p(8He, dfHe forthe spectroscopy of 7He.
It is well known that nuclei have excited states.
There is a famous exception from this rule, the absence of excited states in 3He and 3H. Another kindof exception was considered to be 7He. This nucleus
was investigated for 30 years in many reactions withstable beams, and no excited states were found. As aresult, 7He began to be considered as a nucleus which
may not have excited states.
Exotic nuclear beams are the most promising tool
to study as neutron rich systems as 7He. We usedbeam of 8He at 50 A MeV, that was produced by the
RIPS facility, and studied the p(8He,d)7He reaction
with the CH 2 and C targets. To study transfer reactions with exotic beams, a special detection system, the
RIKEN telescope, was designed (Fig. 1). It represents
a stack of solid-state position-sensitive detectors thathave large area and annual hole. Using this telescope,
we detected deuterons at small angles in the laboratory
system (5°-25°) corresponding to a high cross section.
Particles from the 7He decay (6He, 4He, and neutrons)
were measured by the downstream detectors (Fig. 1).
The obtained deuteron spectra (inclusive and detected in coincidence with 6He, 4He, and neutron)
showed not only the well known ground state of 7He,
but also an excited state. For example, this excitedstate is seen in Fig. 2, where we show the spectrumof deuterons detected in coincidence d + 4He + n.
The ground state is not seen in this spectrum, because
7He g .s . is lower than the 4He-decay threshold. The
most interesting finding is that the revealed excited180~--~--------~

60

E above n+6He (MeV)
Fig. 2. Deuteron spectrum from reaction p(8He, dna).

'He
3.3±0.3 MeV

r-2.2MeV
I.80MeV
n+6He*(2+)
0.44 MeV
r=O.l6MeVoVe
0.975 MeV
3n+4HeFig. 3. Decay scheme of 7He.

state decays predominantly into 3n + 4He, but notinto n + 6He. The obtained parameters of 7He* are
E = 3.3 ± 0.3 MeV (energy above the n + 6He threshold), r = 2.2 ± 0.3 MeV, and the decay branchingra/r tot = 0.7 ± 0.2. The 7He decay scheme is shownin Fig. 3.
Most likely, the 7H~ excited state ' has a structurewith an excited neutron on the top of 6He-core thatis in the excited 2+ -state. It is consistent with thestructure of 8He used as a beam: the 8He wave function
obtained in the a + 4n model l ) shows 2 ) that the 6Hesubsystem has mainly J7r = 2+. The measured decaybranching gives a weight of 6He* in 7He* as P = 0.9 ±0.1.
References

Fig. 1. Scheme of the experimental setup.

1) M. V. Zhukov, A. A. Korsheninnikov, and M. H.
Smedberg: Phys. Rev. C 50, R1 (1994).
2) M. V. Zhukov: private communication.

71

RIKEN Accel. Prog. Rep. 32 (1999)

Momentum Distributions of Projectile Fragmentsfor Light Proton Drip-Line Nuclei
M. Mihara, M. Fukuda, T. Fukao, M. Tanigaki, T. Onishi, K. Matsuta, Y. Nojiri, T. Minamisono,
T. Ohtsubo, M. Ishihara, T. Nakamura, S. Fukuda, S. Ito, T. Kobayashi, S. Momota,
A. Ozawa, T. Suzuki, I. Tanihata, and K. Yoshida
NUCLEAR REACTIONS: 9C + Si, E = 55 MeV/nucleon, 7Be, 8B, 9C + Be, C, AI,[ E = 30-70 MeV/nucleon; Measured momentum distributions
In order to elucidate the nature of loosely bound proton, we have measured the longitudinal and transverse
momentum distributions of 7Be and 8B fragments resulting from the breakup of 9C on a thin Si target collided at an energy of 55 MeV/nucleon. The transverse
momentum distributions of fragments for the eBe,
6Li), (8B, 6Li), (9C, 8B), and (9C, 7Be) processes werealso measured with thick Be, C, and Al targets at 3070 MeV/nucleon of collision energy.
Unstable secondary nuclear beams of 7Be, 8B, and
9C were produced through the 12C + Be collision of
a 135A MeV 12C primary beam with the intensity",,500 pnA provided by the RIKEN ring cyclotron, andwere separated by the RIKEN projectile-fragment separator (RIPS). A secondary beam intensity of 2001000 pps was achieved. The particle detector system
was consisted of three parallel-plate avalanche counters (PPACs) placed at intervals of about 30 cm along
the beam axis, four thin (100 and 150 11m) Si counters, and a large (60 cm x 60 cm x 3 mm thick) plastic
scintillator placed about 2 m away from a vacuum
detector chamber within which the most downstream(3rd) PPAC and Si counters were set. For the thin Si
target runs, the 2nd and 3rd Si counters were used as areaction target with the thickness of 250 11m which wasenough thin to suppress the energy spread of projectile fragments in the target, and the next (3rd and/or
4th) counters after the target were used for particle
identification. For the thick Be, C, and Al target runs,
each target was inserted between the 1st and 2nd Si
counters so that the incident particles lose their kinetic
energy by about 20 MeV/nucleon in the target. The
projectile fragments produced in each reaction target
were clearly identified by means of tlE in the Si andplastic counters and by the time-of-flight (TOF) between the PPACs and the plastic counter. The longitudinal momentum of the projectile fragments was deduced from the TOF, and the transverse momentum
from the horizontal positions of the PPACs and plastic counter which gave the horizontal emerging angleof fragments.
The widths (FWHM) of the momentum distributions were deduced from the width of present spectra by subtracting that of the system resolutions,72

1

which were compared with the Goldhaber model. 1) In
Fig. 1, ratios of the present momentum widths to theones expected from the Goldhaber model are plotted
as a function of the separation energy of removed nucleons. The transverse momentum widths for eachfragmentation process does not show any dependenceson the target and beam energy, so that the averaged
values were possible to show in this figure. The result reported previously on the momentum distributions of 7Be observed through the 8B fragmentation 2)
is also shown. The widths which become narrower
with decreasing the separation energy are, however,much broader than those for the case of neutron richnuclei 3- 5 ) as seen in Fig. 1. The transverse momentum
widths are about 50% larger than the longitudinal ones
for the case of the one-proton removal from 8B and 9C.

1.2 ~----.---~----.--~--~-~----,
8_______._ ___ ___ ___ ._ _ _____ ___ ._.. _ ___ ______7~ .f._ ~ _ _

1.0

...
GI
.0
CII

r.

~\

0 .8

'0

~~ "0.6 ®

-

8

Q.
Ie

~w 0.4

!

B

g
12

Be

0

0 .2

D~1
11

0.0

a

Li

14

•
•

Be

o
o

Be

2

Separation

3·Jp.PI!,-')p , PIh·jn,PI!
· 2n , PI!

4

5

Energy

(MeV)

®
181

-Jp,p.!.
.')p,p.!.

6

Fig. 1. Ratio of the experimental momentum width to thewidth expected from the Goldhaber model plotted as afunction of the separation energy of removed nucleon( s).

References
1) A. S. Goldhaber: Phys. Lett. B 53, 306 (1974).
2) M. Mihara et al.: RIKEN Accel. Prog. Rep. 30, 55(1997).
3) J. H. Kelly et al.: Phys. Rev. Lett. 74, 30 (1995).
4) F. Humbert et al.: Phys. Lett. B 347, 198 (1995).
5) M. Zaher et al.: Phys. Rev. C 48, R1484 (1993).

RIKEN Accel. Prog. Rep. 32 (1999)

Charge Exchange Reaction of 14Be
S. Takeuchi, S. Shimoura, T. Motobayashi, H. Akiyoshi, Y. Ando, N. Aoi, Z. Fiilop, 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, L. Zhong, and M. Ishihara
NUCLEAR REACTIONS: 1,2H(l4Be, 14B*), 74 A MeV;
[ Charge exchange reaction; Isobaric analog state; Neutron halo
Charge exchange reaction 14Be(p, n) 14 B* in inverse
kinematics has been performed to investigate the Isobaric Analog State (lAS) of 14Be and its neutron halo
structure. The present reaction is useful to excite lAS,
as shown in the recent work 1,2) of the neutron halo
nucleus 11 Li. The lAS of 14Be is characterized by
its isospin of T = 3 while the other populated states
are mostly T = 2 states. It is expected that T = 2
states of 14B* decays to many channels, but only the
12Be + p + n channel (T = 3 and 2) is relevant to
the lAS because of the isospin selectivity (see Fig. 1).
Thus, the lAS can be revealed by detecting 12Be, proton, and neutron in coincidence.

T=3
16.73

T=3 /~~

14:g'«IAS) ......... 16.77

T=3,2

12J3e + p + n

14Be

14.55

T=2

113e + d
11.46

T=2,1

l1Be + t

o

T=2

1'13
Fig. 1. Energy level scheme associated with the charge
exchange reaction and particle decay of 14B*. Energies
are shown in MeV.
In order to identify the Fermi transition of 14Be tolAS, the (d, 2n) reaction was also measured in thepresent experiment. The (d, 2n) reaction does not populate Fermi states, while the (p, n) reaction can cause
the Fermi transition and the Gamow-Teller transition.
The lAS excited by Fermi interaction can be identified

1

by subtracting the yield of the Gamow-Teller transition.
The 14Be beam was produced by using the projectile fragmentation of a 100 A MeV 18 0 beam on1110 mg/cm 2 9Be target. Energy of the incident 14Be
beam was determined event-by-event by measuring thetime of flight (TO F) between F2 and F3 plastic scintillators whose thicknesses was 0.5 and 0.3 mm, respectively. After traversing the beam detectors at F2
and F3 , the 14Be beam was focused on the (CH 2 )n,(CD 2 )n, and C targets with the thicknesses of 187,
204, and 152 mg/cm2, respectively. The average beamenergy was 74 A Me V at the middle of the target witha typical intensity of about 104 cps. The C target
was used for subtracting the contributions from carbon nuclei in the (CH 2 )n and (CD 2 )n targets. Outcoming charged particles were detected by ~E andE hodoscopes which were located at 492 cm downstream from the target. Those hodoscopes consistedof vertically segmented 5 mm thick plastic scintillators and two layers of horizontally segmented 6 cm
thick plastic scintillators. Velocities of charged particles and of neutrons were determined by the TOF
over the 492 cm flight path between the target and thehodoscope. Charged particles were identified by usingthe ~E-E and TOF-E methods.
The decay particles from 14B* were detected in coincidence, from which the momentum vectors were determined by combining their velocities with hit positionon the hodoscope. The energy and width of lAS will
be obtained from the decay energies of 12Be, proton,and neutron.
In the present states we are working on the calibration and particle identification. Momentum resolution(~P / P) is about 1.5% for charged particles. Further
analyses are in progress to determine the energy andwidth of lAS.
References
1) S. Shimoura et al.: Nucl. Phys. A 630 , 387c (1997).
2) T. Teranishi et al.: Phys. Lett. B 407, 110 (1997).

73

RIKEN Accel. Prog. Rep. 32 (1999)

Coulomb Dissociation of 11 Be and 15C
N. Fukuda, T. Nakamura, T. Kobayashi, H. Otsu, N. Aoi, N. Imai, H. Iwasaki,
T. Kubo, A. Mengoni, M. Notani, H. Sakurai, S. Shimoura, T. Teranishi,
Y. X. Watanabe, K. Yoneda, and M. Ishihara[11 Be+ Pb, lSC + Pb, Coulomb dissociation, Direct breakup, Coulomb post-acceleration]

We have measured the Coulomb dissociation of 11 Be
as well as lSC using the radioactive beam line RIPS at
RIKEN Ring Cyclotron Facility.
A significant El strength at lower excitation energy
has been observed by the Coulomb dissociation experiment for the neutron halo nuclei 11 Bel) and 11 Li. For
the explanation of this characteristic feature, following three intuitive pictures are proposed 2 ): a direct
breakup mechanism; a resonant breakup mechanism;
and a free-particle breakup mechanism. The results ofthe previous 11 Be Coulomb dissociation experiment 1 )support the direct breakup mechanism based on the
shape of the low-lying strong E1 distribution andbased on the significant longitudinal momentum difference between the halo neutron and the core nucleus :namely, Coulomb post-acceleration effect.
Though the direct breakup mechanism provides agood discription of the experimetal results, the mixture
with the free-particle mechanism cannot be excluded,
which can be probed by the transverse Coulomb postacceleration effect. Aming at the more detailed understanding of the reaction mechanism, we did experiment with emphasis on the measurement of thetransverse Coulomb post-acceleration effect. Breakup
of lSC as well as 11 Be has been measured, scince lSC
is similar nucleus to 11 Be having a 231/2 valence neutron, whereas , its one-neutron separation energy (Sn =1.2 MeV) is larger than that of 11 Be (Sn = 0.5 MeV).
The comparison between these nuclei may give us aknowledge of the dependence of the reaction mechanism on the one-neutron seperation energy.
Another interest is a higer order effect in the
Coulomb dissociaion. In the previous experimental results, the angular distribution of the outgoing particle
suggests that the E1 transition is dominated in the
Coulomb dissociation. But, it was difficult to make aquantitative discussion about the mixture with higher

74

order effects due to the insufficient statistics. We havemeasured the angular distribution of outgoing particles
more precisely than measured in previous experiment.
In present experiment, the momentum vectors of thetwo outgoing particles, lOBe + neutron 4 C + neutron), have been measured in coincidence for the reaction of 11 Be + Pb esC + Pb) at 74 MeV/nucleon. The
11 Be and lSC ion beams have been produced from the18
0 primary beam at 100 MeV/nucleon. The typicalsecondary beam intensities were about 50 kcps for both
nuclei. The experimental setup was almost the sameas that for the previous 11 Be Coulomb dissociation experiment. The energy of the beam was determinedfrom the time of flight measured with two thin plastic
scintillators which were placed 4.65 m apart along thebeam line. The position and direction of the beam were
measured with two sets of Multi-Wire Drift Chamber(MWDC). The momentum of the outgoing charged
particle was measured by the magnetic spectrometerwith a tracking drift chamber and by the plastic scintillator hodoscopes. For the neutron detection , a special
care was taken to determine the transverse momentum shift with a high precision. We used two layers of
the plastic scintillator hodoscope (2.1 x 0.9 m 2 ) whichis composed of long plastic scintillator bars in order
to cover a large angular acceptance. The neutron hodoscopes were placed at the 0 degree position covering
angles up to 17 degree, corresponding up to 112 Me V / cin momentum. The number of accumulated events inthe current experiment are about twenty times as manyas that in the previous experiment. The analysis of theexperimental data is in progress.

e

References
1) T. Nakamura et al.: Phys. Lett. B 331, 296 (1994).
2) T. Kido et al.: Phys. Rev. C 53, 2296 (1996).

RIKEN Accel. Prog . Rep . 32 (1999)

Shell Structure Study of the Proton Rich Nucleus
17Ne via the (p, 2p) Reaction
H. Otsu, T. Kobayashi, T . Ujiie, M. Sekiguchi, T. Okuda, A. Ozawa, K. Yoshida,
T. Suzuki, 1. Tanihata, S. Ito, T. Nakamura, and N. Fukuda[NUCLEAR REACTIONS IH(17Ne, 2p)p I5 0, E/A = 60 MeV/ul
The 17Ne(p,2p) reaction was measured by meansof an inverse kinematics method with the radioactive
17Ne beam.
A variety of new features in nuclear structures havebeen revealed via studies to use unstable nuclei. N eutron skin or halo structuresl} are the topic of thisdecade. On the other hand, the proton shell structures should be also studied in order to answer thequestions such as: (1) Can protons also form the skinor halo structure? (2) How the Coulomb interaction
destructs the isospin symmetry feature?
One of the best ways to obtain the proton shell information is to ' measure the proton knock-out (p, 2p)
reaction. 2,3) The direct knock-out reaction becomesdominant by means of the probes with a high energy
enough to interact with individual nucleons in the nucleus. For nucleon probes, such energies are in theregion larger than 100 MeV where the de Broglie wavelength becomes the same order of the size of nucleons.
By means of the inverse kinematics, the (p, 2p) reaction
is utilized to study for structures of unstable nuclei.
A proton rich nucleus like l7Ne is one of the candidates for the proton halo nucleus, while the protonshell configuration of 17Ne is not well known. If a proton 8 shell is dominant in the ground state configuration, it is possible to form the proton halo structure.
On the other hand, if a proton d shell is dominant, thehalo structure is not formed because of the centrifugal
force. One supporting evidence for the 8 shell intrusion
is indicated from low lying states of the neighborhood
nucleus 16F. Note that the 8 shell intrusion means thatthe 8 shell is below the d shell in terms of energy. Figure 1 shows the level schemes of 16F and 150 with areference of the 17Ne ground state. The ground and
0.193 MeV states correspond to (281/2tr E9 (IPl/2)V,while the 0.424 MeV and 0.721 MeV states correspondto (ld 5/ 2)7l'E9(1Pl/2)v, In this way, the 281/2 shell islocated below the Id 5 / 2 shell in 16F. Such an intrusion
may also occur in 17Ne.
The proton ground state information can be derived
from the final state of the proton knock-out reaction.
The 16F nucleus , which is a residual nucleus, decays
to p + 150. A decay to the excited states of 150 is notpossible energetically from the states less than
4.65 MeV. The state of 16F can be reconstructed via
the invariant mass method from 4-momentum vectorsof proton and 150. The proton shell configuration of
l7Ne can be obtained from population to these four

5.183 1/2+

3.7581+---0.7213---0.4242---0.1931----~O-~. ~.5~~ .
1.4790I

17Ne

Fig. 1. Low lying states and their spin parity in 16F and
15 0 with the 17Ne ground state as a reference.

states.
The 17Ne beam around 60 MeV /u on target wasprovided by the RIPS facility. The typical 17Ne beam
intensity was 4 x 10 4 S-I. The beam was accompanied
by other particles, mainly 15 0 and 2oNe. Then, thetotal beam intensity was 10 times larger than that of
the 17Ne beam. Each beam particle was detected andidentified event by event with two plastic scintillators.
One of the plastic scintillator was located at F2 position of the RIPS and the other scintillator was locatedjust upstream the target position. Two drift chambers for beam track reconstruction were set between
the downstream plastic scintillator and the target position. Each of the drift chamber had 4 planes for x
and 4 planes for y. A CH 2 target with a 200 mg/cm 2
thickness was used. A carbon target with equivalent
thickness for same beam energy loss was also used
for subtraction of carbon contribution from the CH 2
target. Scattered and knocked-out protons were detected in coincidence by two proton telescopes locatedat ±43.5°, respectively, and 30 em away from the target. The proton telescope consisted of 8 planes of drift
chambers and a NaI scintillator. The residual particles, proton and 150, were detected in coincidence andparticle-identified by .6.E - E detector hodoscopes located at 0° and 5 m downstream of the target. The.6.E

75

hodoscope consi$ted of ten plastic scintillators withsize of 100(H) x 1000(V) x 5(t) mm 3 . The E hodoscope consisted of 16 plastic scintillators with sizeof 1100 x 60 x 60 mm3 . A Helium-bag was inserted
along the flight path of the residual particles in order to decrease the multiple scattering effect, especially for 15 0. The energies of residual proton and 15 0
were determined by the time of flight obtained by thesignals from the ~E - E hodoscopes and from thebeam detectors. The momenta were determined from76

the positions on the detector walls and from the energies.
The analysis is now in progress.
References
1) 1. Talmi and 1. Unna: Phys. Rev. Lett. 4 , 469 (1960).
2) G. Jacob and Th. A. J. Maris: Rev. Mod. Phys. 38, 121(1966).
3) K. Hatanaka et al.: Phys. Rev. Lett. 78, 1014 (1997);
T. Noro et al.: Nucl. Phys. A 629, 324 (1998).

RIKEN Accel. Prog. Rep. 32 (1999)

Magnetic Moment and Electric' Quadrupole Momentof the I8N Ground State
H. Ogawa, K. Asahi, K. Sakai, A. Yoshimi, M. Tsuda,*1 Y. Uchiyama, T. Suzuki, K. Suzuki, N. Kurokawa,*2
M. Adachi, H. Izumi, H. Ueno, T. Shimoda, S. Tanimoto,*3 N. Takahashi, W.-D. Schmidt-Ott,
M. Schafer,*4 S. Fukuda,*5 A. Yoshida, T. Kubo, H. Okuno, H. Sato, M. Notani,
N. Aoi, K. Yoneda, H. Iwasaki, N. Fukuda, M. Ishihara, and H. Miyatake[18N g .s .; ,8-NMR; Measured magnetic moment, Electric quadrupole moment]
The magnetic moment and electric quadrupole moment of the neutron-rich nucleus 18N have been determined by a ,8-NMR method, taking advantageof the fragment spin polarization induced in theintermediate-energy projectile fragmentation reaction.
To assure the existence of a sufficient polarization
prior to the resonance search, a scheme of polarization measurement by means of an adiabatic field rotation has been developed and successfully incorporated in the ,8-NMR experiment. The polarization
P = 2.2 ± 0.7% has been obtained for 18N fragments from the 22Ne(110 MeV /u) + 12C reaction at(1£ = 3.5 ± 1.0° and p = 8.07 - 8.32 GeV /e. And
from the observed resonance in a Pt stopper, the magnetic moment for the 18N ground state has been determined to be Iltl = 0.3279 ± 0.0013 ItN. The 18N
fragments have also been implanted in a single crystal
Mg stopper. From the observed quadrupole frequency
leqQ/hl = 73.2 ± 1.4 kHz, the electric quadrupole moment IQI = 12.3 ± 1.2 mb has been deduced by using
the field gradient q given Refs. 1 and 2.
Shell model calculations were made using the
OXBASH code 3) with the two sets of effective twobody interactions, PSDMK3,4) and PSDWBT. 3,5) In
Fig. l(a) the experimental magnetic moment (negative in view of the calculated It values) is comparedwith the theoretical It. The agreement is quite goodwith the PSDMK interaction calculation. On the other
hand, the PSDWBT calculation underestimates the Iltl
value slightly. The experimental electric quadrupole
moment is compared with the shell model calculationsin Fig. l(b). The calculated Q's seem to be quite stable against the choice of the effective interaction, butthere appear substantial deviations from the experimental Q when the standard values for the neutron
effective charge en are employed. The agreement improves by taking a much smaller value of en = 0.3. The
quenching of en in a neutron-rich nucleus was previously indicated in the Q-moment measurement for 14B
and 15B.6)
*1
*2

*3
*4
*5

Ultrasound Engineering Department, GE Yokokawa Medical
System, Ltd.
Research Laboratory for Nuclear Reactors, Tokyo Instituteof Technology
Central Research Laboratory, Hitachi, Ltd.
Roland Berger and Partner GmbHThe Energy Research Center, Wakasa Bay

PSDMKPSDWBT

(b)
o

-0.1

-0.2

-0.3

-0.4 0MagnetiC moment (1lN)(mb)

Fig. 1. Comparisons of the experimental (expt.) J.L andQ values for the 18N ground state (I1T = 1-) withshell-model calculations using two different effective interactions (PSDMK, PSDWBT). Broken lines accompanying the experimental line indicate the experimental error. (For J.L the error is so small that these lines
may not be well identified). In the Q moment calculations, the effective charge for neutrons was varied fromen = 0.3 to 0.5, while that for protons was fixed at
e p = 1.3 (because it hardly affects the Q value).

The It value recently reported 7 ) and the Q value inferred in Refs. 7 and 8 from the level mixing resonanceexperiments by Leuven group are different from thepresent results by factors of about 0.5 and 3, respectively. Our NMR and NQR spectra, however, clearly
indicate that there exist no resonances at the frequencies corresponding to such It, Q values.
References
1) T. Minamisono et al.: Phys. Lett. B 420, 31 (1998).
2) M. Tokman et al.: Chern. Phys. Lett. 265, 60 (1997).
3) B. A. Brown, A. Etchegoyen, and W. D. M. Rae:OXBASH, MSU Cyclotron Laboratory Report, No. 524,
p. 1 (1986).
4) D. J. Millener and D. Kurath: Nucl. Phys. A 255, 315(1975).
5) E. K. Warburton and B. A. Brown: Phys. Rev. C 46,
923 (1992).
6) H. Izumi et al.: Phys. Lett. B 366, 51 (1996).
7) G. Neyens et al.: Presentation in EN AM98 Conf.
(1998) .
8) G. Neyens et al.: Phys. Lett. B 393, 36 (1997).

77

RIKEN Accel. Prog. Rep . 32 (1999)

The First Measurements of Half Lives and Neutron Emission
Probabilities of Very Neutron Rich Nuclides of
Mg, AI, Si, and P
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. X. Watanabe, A. Yoshida, X. Zhou, and M. Ishihara[RADIOACTIVITY 31-33Na , 32-37 Mg , 34-39 Al , 37- 42 Si " 41- 43p. measured T 1/ 2, delayed n-emission probabilities]
We report on the measurement of j3-decay half lives(Tl/2) and j3-delayed neutron emission probabilities(Pn ) for very neutron-rich nuclei with Z = 11-15.
This was the first measurement for 35-37 Mg, 36-39 AI,
37-42 Si, and 43p.
The experiment was carried out at RIPS. Neutronrich nuclei were produced by the projectile fragmentation reaction of 70 MeV/nucleon 48Ca beam with 9Be
and 181Ta targets. Each fragment was identified online by measuring its time of flight and energy deposits
in two Si detectors (0.35 mmt and 0.5 mmt). The nuclei were implanted separately into an active stopper,a 3 mmt Si detector. When a nucleus with Z 2: 11 was
identified, the primary beam was then turned off for aperiod much longer than the expected Tl/2' and during
this beam-off period the j3 decay of the implanted nucleus was observed. The stopper Si detector was used
for the detection of {3 rays. A neutron detector system
was placed around the stopper to detect j3-delayed neutrons in coincidence with j3 rays. The neutron detector
consisted of 46 proportional counter tubes (32 mm diameter and 300 mm length) filled with 4 atm 3He. The
tubes were surrounded by organic glass for moderationof neutrons.
The preliminary results on T 1 / 2 are summarized
in Fig. 1. Tl/2 were deduced from the maximumlikelihood fits to the decay curves, obtained from thetime difference between the implantation of a nucleus
and the detection of j3 rays.
The tentatively deduced Pn are shown in Table 1.
Multiple neutron emission events are clearly indicatedby Pn > 100%. The efficiency of the neutron detector
was calibrated to be 11.4 ± 2.3% from the measurement of j3-delayed neutrons of 15B, which has a known
Pn of 100%.1) The efficiency was also deduced to be
21.5 ± 4.2% from the measurement of j3-delayed neutrons of 14Be, which is a low energy neutron emitter(290 keV)2) compared to 15B.l) Here we adopted theefficiency obtained from the measurement of j3-delayed
neutrons of 15B, and it should be noted that the errors
do not include ambiguities resulting from the energy
dependence of the efficiency.

78<> IIao~----XAI

0111
):( P

18

20

22

24

28

26

30

Neutron Number

Fig. 1. Plot of half lives versus neutron number. The
preliminary results of this work are plotted together
with the literature values (dashed lines) compiled inRef. 3
Table 1. Preliminary results on ,B-delayed neutron emission
probabilities Pn .
nucleusPn (%)

nucleusPn (%)

31Na

82 ± 4237AI

55 ± 1132Na

59 ± 1738Al

84 ± 1933Na

136 ± 34

39Al

97 ± 22

32Mg

6±4

37Si

15 ± 833Mg

50 ± 1838Si

28 ± 734Mg

58 ± 1239Si

60 ± 1335Mg

52 ± 1140Si

53 ± 1238Mg

103 ± 48

48 ± 12

41Si

34Al

30 ± 641p

71 ± 2135AI

43 ± 942p

57 ± 1336AI

55 ± 1143p

84 ± 47

References
1) R. Harkewicz et al.: Phys. Rev. C 44, 2365 (1991).
2) N. Aoi et al.: Z. Phys. A 358, 253 (1997).
3) G. Audi et al.: Nucl. Phys. A 624 1, (1997).

RIKEN Accel. Prog. Rep. 32 (1999)

Quadrupole Moment of 39Ca
K. Matsuta, T. Minamisono, M. Fukuda, M. Mihara, T. Onishi, K. Sato, M. Sasaki, K. Minamisono,
C. Ha, T. Miyake, H. Akai,*1 T. Ohtsubo, S. Momota, Y. Nojiri, S. Fukuda,*2 K. Yoshida,
A. Ozawa, T. Suzuki, I. Tanihata, G. F. Krebs,*3 J. R. Alonso,*3 and T. J. M. Symons*3
NUCLEAR STRUCTURE, Nuclear magnetic resonance,[ Measured quadrupole moment of 39Ca ground state
The electric quadrupole (Q) moment of 39Ca (In =3/2+, TI/2 = 0.86 s) has been determined for the firsttime by applying the {3-Nuclear Quadrupole Resonance((3-NQR) technique.
The experimental procedure is basically the same as
the previous work. l ) The polarized {3-emitter 39Ca wasproduced through the projectile fragmentation process
in the 100A-MeV 40Ca on Au collision and was purified
using the fragment separator RIPS. For the optimum
polarization, the 39Ca nuclei which were ejected at 2.0 0
with the momentum higher than that of the beam velocity by 1.0% were selected. Thus polarized 39Ca nuclei were slowed down by an energy degrader of controllable thickness and were implanted into a single crystal
CaC03. The CaC0 3 catcher was placed in a strong
magnetic field Ho = 9 kOe, in order to maintain thepolarization and for the NMR. The crystal c-axis wasset perpendicular to the field. For the detection of thequadrupole coupling eqQ/h, the {3-NQR method wasused. In this method, the polarization was inverted byapplying 6 rf oscillating magnetic fields sequentially,
while the polarization was monitored through the {3ray asymmetry. The set of frequency was programmed
for each quadrupole coupling constant based on the
known magnetic moment f..L = 1.0217 f..LN. The present
Larmor frequency is 4.673 MHz.
Figure 1 shows the observed (3-NQR spectrum. Although the detected polarization effect for 39 Ca in
CaC0 3 was 10 times smaller than the one in CaF 2 , thepresent resonance is identified for the 39Ca in the substitutional site, since we detect no other significant resonance for leqQI/h at frequencies lower than 3.2 MHz.
From the chi-square fitting analysis on the spectrum,
the quadrupole coupling constant was determined tobe leqQI/h(39Ca in CaC0 3) = 0.60 ± 0.04 MHz. The
electric field gradient (EFG) at the substitutional siteof Ca in the crystal was predicted to be q = (7.0 ±1.0) x 10 20 V /m 2 from the first principles calculation of

*1

*2

*3

1

~ 0.4
'-'
d.)

~ 0.2
..d

U 0.0
S-0.2
d.)

§ -0.4a)~~ -0. 6 1:::L....-________---1-......J.........J..._..l..._..l..._..l...___L.___L.---L~.......

500 1000 1500 2000 2500 3000
eqQ/h(kHz)~ 0.5 n---.----r---,---.----r----.-----.__r--r--...---.,...--n
'-'

~ 0.4

a 0.3

b)

..d

U 0.2
0.1

S

S O.OI----+--'I=-++-----P-+--+--lS -0.1~~.......

-0.2 ~-'--.....I...._.....I.-___I_---1-......J..._..l...___L.___L.---L---'-____.:Il
0
500
1000

eqQ/h (kHz)Fig. 1. NQR spectrum for 39Ca in CaC0 3. a) Over-all
view, b) Close- up view.

electronic band structure based on the KKR method.
Since the EFG has not been measured yet, this predicted value of EFG was used for the determination of the Q moment. As a result, the quadrupole
moment of 39Ca was determined to be IQ(39Ca)1 =36 ± 7 mb. The shell model value 26 mb predicted by
the OXBASH code agrees with the present quadrupole
moment.
References
1) K. Matsuta et al.: RIKEN Accel. Prog. Rep. 29, 60(1996).

Department of Physics, Osaka University
Energy Research Center, Wakasa Bay
LBL, USA

79

RIKEN Accel. Prog. Rep. 32 (1999)

Production of 44Ti at the RIKEN RIPS Facility
Zs. FUlop, M. Golovkov, T. Kato, K. Kimura,*l H. Kudo,*2 Y. Mochizuki, H. Otsu,
A. Ozawa, H. Petrascu, H. Sakurai, T. Suzuki,*2 I. Tanihata, Y. Wakasaya,
K. Yoshida, R. N. Boyd,*3 and E. Somorjai*4[Half-life, N ucleosynthesis]
The observation of the E, = 1157 keY line -characteristic to the decay of 44Ti- in the Cassiopeia AI)
supernova called for the accurate determination of thehalf-life of 44Ti (T 1/2 rv 60 y). In lack of reliable halflife data the initial amount of 44Ti ejected by the Cassiopeia A cannot be given with a precision needed totest the various supernova models. In fact, since 44Ti
can also be produced in meteorites by means of cosmicray interactions, the half-life of 44Ti also has impact on
the galactic cosmic ray flux and its modulation by solar
activity.2) The abundance of 44Ca in th~ solar system
also may depend on the half-life of 44Ti.3)
In our study we have tested the feasibility of the
RIKEN RIPS radioactive beam facility to produce 44Ti
beam. In order to estimate the half-life of 44Ti with theimplantation method (1) known amount of 44Ti shouldbe implanted to a stopper (or stack of stoppers) and (2)the ,-activity with respect to a 44Ti characteristic line
should be determined. During our test measurement
the 44Ti was produced by fragmentation of 2 particle nA, 90 A MeV 46Ti on 200 mg/cm 2 thick Beryllium target. The projectile fragments were separated
by the RIPS fragment separator with a 221 mg/cm 2
thick Aluminium wedge degrader placed between the
two analyser dipole magnets. Through appropriate
settings of the fragment separator we achieved highsecondary beam intensity (2.10 5 Is) with high ratio of
44Ti nuclei (> 50%) without implanting isotopes contributing to the gamma activity of the sample. Also,
we kept the content of 42SC (same A/Z as 44Ti, i.e.
TOF determination is not enough to separate this isotope from 44Ti) to minimum « 5%).
Plastic scintillators have been mounted at F2 andF3 foci for on-line TOF measurements at full intensity,
while a Si-detector at F2 focus for low intensity (200/s)
energy loss measurements during the secondary beamtuning. The separated fragments have been implanted
into a 1 mm thick plastic scintillator stopper allowing
a loss-free determination of the number of implanted
ions. Behind the stopper, an additional plastic scintillator served to check the presence of ions penetrating
the stopper. In addition, two Parallel Plate Avalanche
Counters 4) (PPAC) have been mounted to F3 focus todetermine the distribution of the implanted ions in the*1 Nagasaki Institute of Applied Science
*2

.. 3
.. 4

80

Niigata University
Ohio State University, USA
ATOMKI, Hungary

stopper plastic scintillator. The information on the
distribution can be used to take into account the effectof the finite source size on the activity determination.
The ,-activity of the implanted sample has been investigated by high-efficiency (120%) HPGE gamma detector. The laboratory background was suppressed by
a 10 em lead shield with additional 1.5 mm copper and
10 mm steel layers. A Lucite plate with a thickness of
2 mm supported the irradiated scintillator at 27 and
57 mm from the detector. Point-like sources of 60 Co
and 22N a have been used for efficiency calibration.
There is no contamination observed in the gamma
spectra of the irradiated sample with the exceptionof the 44SC m isomeric state decay (E')' = 271 keY,
T 1/2 = 58.6 h). After 12 h of irradiation the decay
yield of 44Ti (detected as the gamma-decay of the 44Sc
daughter at 1157 keY) is higher than the 40K laboratory background. Due to the excellent shielding of thesystem and the very small ,-contamination in the irradiated scintillator from the implantation, the 1157 keY
peak originating from the decay of 44Ti is the strongest
in the spectrum. To follow the errors in the determination of the activity of the implanted 44Ti we compared
the yield of the 44SC daughter 1157 keY ,-line at twosource-detector distances, one week and 14 weeks after the implantation. Having taken into the accountthe contribution of the 44SC m isomeric state decay, nodifference in the determined activities have been foundwithin the achieved statistical limit (5%). It supportsthat no loss in the implanted 44Ti occurred via diffusion and also proves the reliability of the efficiency
determination.
Since the 1157 keY line is not the only one characteristic to the decay of 44Ti, also an investigation isunder course concerning the systematic errors occurring at the determination of the 44Ti half-life using low
energy (68, 78 keY) gamma lines from its decay.
References
1) A. F. Iyudin et al.: Astron. Astrophys. 284, L1 (1994).

2) G. Bonino et a1.: Science 270, 1648 (1995).
3) D. Bodansky et al.: Phys. Rev . Lett. 20, 161 (1968).
4) H. Kumagai and 1. Tanihata: RIKEN Accel. Prog. Rep.
31, 164 (1998).

RIKEN Accel. Prog. Rep. 32 (1999)

Development of Polarized 129Xe Solid for Polarizationof Unstable Nuclei
K. Sakai, Y. Mizumura, T. Suzuki, K. Asahi, H. Ogawa, A. Yoshimi, Y. Uchiyama,
M. Nagakura, H. Sato, A. Yoshida, T. Kubo, H. Okuno, M. Ishihara,
K. Yoneda, M. Notani, H. Izumi, and S. Fukuda*[Polarized 129Xe solid, Cross polarization, Nuclear magnetic moment]
We have developed a polarized 129Xe solid as animplantation medium (stopper) in which unstable nuclei are implanted and and their spins are polarized
by the cross polarization process. A stopper for sucha purpose should span a sufficiently large volume forthe implantation, and should afford a high polarization P solid , a long spin relaxation time T 1 , and a small
spin-depolarization rate Dcross during the polarizationtransfer under a few gauss (G) field. As we reported
previously,1,2) about 80 mg of the 129Xe solid has beenobtained with Psolid f".J 1%, about 0.27 times the 129Xe
gas-phase spin polarization (Pgas ) produced with optically polarized Rb atoms, and T1 f".J 25 min. This
result implies that there is a large polarization loss
(D1os s f".J 73%) during the condensation from the gas tosolid phases, suggesting the importance of decreasing
Dloss as well as of increasing P g as and Tl for achieving
higher Psolid. In present report, we describe the resultof recent improvements aiming at decreasing the D1os s .
In a typical procedure to produce a polarized 129Xe
solid, a 129Xe gas at a pressure PXc = 1-3 atm is introduced into a cylindrical glass cell, 4 cm long and
2 cm in diameter, together with a small amount of Rbvapor. The optical pumping is carried out by warming
up to 350 K and illuminating it with a circularly polarized light from diode lasers. After the polarization the
P gas reaches 3- 10%, the cell is cooled down by putting
its bottom part (8 x 20 x 2 mm 3 ) into contact with aliquid nitrogen vessel. Thus, the 129Xe gas condenses
into a solid, maintaining its polarization in part.
The large Dloss observed previously is supposed tohave resulted from i) the interaction between the 129Xe
and Rb in the gas phase and ii) short relaxation time
Tl after the condensation. The short Tl may b e due
to a relatively high final temperature (> 140 K) for thesolid phase, since Tl estimated for the solid at such atemperature was less than 4 min. 3 ) In order to remove
the Rb vapor from the gas as soon as the pumping
was finished, we cooled the main part of cell without
a delay to about 270 K by blowing the cell with a cold
nitrogen vapor before a liquid nitrogen was poured in.

Furthermore, in order to cool the 129Xe solid to alower temperature in a shorter time, the thermal contact between the cell and liquid nitrogen vessel was reinforced by introducing a cold finger and copper wire
structure. With such efforts, the 129 Xe gas of PXc ::; 2
atm turned to be able to condense within 5 min after
the cooling was initiated. The various Psolid attainedwith different initial gas pressures were: Psolid = 5%
at 1 atm (f".J80 mg), 3.6% at 1.5 atm (f".J 120 mg), and
0.13% at 2 atm (f".J160 mg). The corresponding polarization losses during the condensation process were:
D10s s ~ 24% at 1 atm, 20% at 1.5 atm, and 96%
at 2 atm. The large Dloss observed at 160 mg may
be explained by a longer time required for the larger
amount of 129Xe to cool down to below 140 K. We
also measured the spin relaxation time T1 after thesolid reached an equilibrium temperature, and measured D cross during the cross polarization process. The
typical value for Tl was about 50 min (Tl ~ 100 min
at largest), while Dcross ~ 5%. The increased Tl indicates that lower temperatures were attained for 129Xein the solid phase.
We plan to apply the present cross-polarization technique for the purpose to polarize 11 Be nuclei. The
presently achieved values for Psolid and T 1 , both forthe 80 and 120 mg 129Xe solids, seem to satisfy therequired conditions for the planned experiment with
11 Be beam. In respect of the volume available for the
implantation, the 120 mg cell would be preferred to the
80 mg one. The time (Tm cas ) available for the measurement of the 11 Be polarization in such a planned experiment depends largely on D cross as well as on T 1 . At
present , T mcas ~ 13 min is essentially determined by
D cross rather than T 1 • The preparation of the plannedexperiment with the 120 mg cell is in progress.
References
1) H. Sato et al.: RIKEN Accel. Prog. Rep. 30 , 64 (1997).
2) H. Sato et al.: Nucl. Phys. A 402, 241 (1998) .
3) M. Gatzke et al.: Phys. Rev. Lett. 70, 690 (1993).

The Energy Research Center, Waka sa Bay

81

RIKEN Accel. Prog. Rep. 32 (1999)

Coulomb Dissociation of 8B at 254 A MeV
N. Iwasa, F. Boue,*I,*2 G. Surowka,*I ,*3 K. Siimmerer,*1 T. Baumann,*1 B. Blank,*2 S. Czajkowski,*2
A. Forster, *4 M. Gai, *5 H. Geissel, *1 E. Grosse, *1 M. Hellstrom, *1 B. Kohlmeyer, *6 P. Koczon, *1
R. Kulessa,*3 F. Laue,*1 C. Marchand,*2 T. Motobayashi, H. Oeschler,*4 A. Ozawa,
M. S. Pravikoff,*2 E. Schwab,*1 W. Schwab,*1 P. Senger,*1 J. Speer,*6 C. Sturm,*4
A. Surowiec,*1 T. Teranishi, F. Uhlig,*4 A. Wagner,*4 and W . Walus*3[ 208Pb(8B, P 7Be)208Pb, Coulomb dissociation]
The Coulomb dissociation of 8B is an alternative
method for extracting the astrophysical S 17 factors forthe 7Be(p, I )8B reaction. I) The S 17 factor at zero energy is the most uncertain input to solar models, andis directly related to predictions of the high-energy 8B_
neutrino flux from the sun: relevant to the "solar neutrino problem." Recently, two Coulomb dissociation
experiments were performed at E(8B) ~ 50 A MeV
at RIKEN,l,2) and the S17 factors were successfully
extracted for the pJBe relative-energy (Erel ) regionsof Erel = 0.6- 1.7 MeV and 0.4- 3.0 MeV, respectively.
These results were found consistent with the results ofthe direct measurement by Filippone et al., Vaughn etal., and Hammache et al. 3)
We have studied the 8B Coulomb dissociation process at 254 A MeV at GSI to obtain the 817 factors for
the El multipolarity at low center-of-mass energies,
and to extract information on the E2 admixtures. A
radioactive 8B beam produced by the Fragment Separator (FRS) at GSI bombarded an enriched 208Pb target with a thickness of 200 mgjcm 2 . The outgoing reaction products, proton and 7Be, were analyzed by theKaon Spectrometer (KaoS) which has a large momentum acceptance of Pmax/Pmin ~ 200% and an angular
acceptance of 140 and 280 mrad in horizontal and vertical direction, respectively. Two pairs of silicon microstrip detectors were installed at about 14 and 31 cm
downstream from the target, respectively, for measuring x- and y-positions of the products before entering
the KaoS magnet. The vertex information was used
to eliminate a large amount of the background events
produced in layers of materials other than the target.
The Coulomb dissociation yields were extracted asa function of the E rel or of the scattering angle 08 of
the p- 7Be center-of-mass with respect to the beam direction. The resultant E rel and 08 distributions were
well reproducible by Monte-Carlo simulations using
the non-resonant-E1 cross section predicted by Typelet al. 4) as well as the resonant-M1 cross section measured by Filippone et al. 3) We also have tried to extract the upper limits for a possible E2 contribution by
*1

*2
*3
*4

*5
*6

82

GSI, Germany
CEN Bordeaux, France
Jagellonian University, Poland
Technische Hochschule Darmstadt, Germany
University of Connecticut, USA
Universitat Marburg, Germany

comparing the experimental and simulated 08 distributions including E2 contributions. We obtained only
a very small E2 amplitude, which is consistent with
the Coulomb dissociation result of Kikuchi et al.;2)
but is not consistent with the result of longitudinalmomentum measurements by Davids et al. 5) Considering this discrepancy, further experimental and theoretical studies are desirable to clarify the amount of
E2 admixture.
By comparing the resultant E re l distribution withthe simulation, the experimental S17 distribution was
extracted. Figure 1 shows our preliminary S 17 factors
at Ere! = 0.25-2.8 MeV. We have omitted the data
points in the region of the M1 resonance (0.5- 0.8 MeV)
because we are primarily interested in the E1 component. Our results are consistent with existing (p, I)
data3) and with other Coulomb dissociation data. 2 )

:e 60
>'.

~40

....

020 1-. ,. . 6"I'm~o o: ----- - --L--- -- ---L2

-

---J

3

Erel [MeV]Fig. 1. Preliminary results for the 5 17 factor (filled circles) together with the (p, .,,) results 3 ) and the Coulomb
dissociation results. 2 ) The solid curve shows the best fit
with the theoretical energy dependence calculated byTypel et al. 4 )References
1) T. Motobayashi et al.: Phys. Rev. Lett. 70,2680 (1994);
N. Iwasa et al.: J. Phys. Soc. Jpn. 65, 1256 (1996).
2) T . Kikuchi et al.: Phys. Lett. B 391, 261 (1997); T.
Kikuchi et al.: Eur. Phys. J. A 3, 209 (1998).
3) B. W. Filippone et al.: Phys. Rev. C 28 , 2222 (1983) ;F . J. Vaughn et al.: Phys. Rev. C 2, 1657 (1970) ; F.
Hammache et al.: Phys. Rev. Lett. 80, 928 (1998).
4) S. W. Typel et al.: Nucl. Phys. A 613, 147 (1997).
5) B. Davids et al.: Phys. Rev. Lett. 81, 2209 (1998).

RIKEN Accel. Prog. Rep. 32 (1999)

Measurements of Interaction Cross-Sections for Carbon Isotopes
at Relativistic Energies and the Halo Structure in 19C
A. Ozawa, o. Bochkarev,*1 L. Chulkov,*1 D. Cortina,*2 H. Geissel,*2 M. Hellstrom,*2 M. Ivanov,*3 R. Janik,*3
K. Kimura, T. Kobayashi, A. A. Korsheninnikov, G. Miinzenberg,*2 F. Nickel,*2 Y. Ogawa, A. A. Ogloblin,*1
M. Pfiitzner,*2 V. Pribora,*1 H. Simon,*2 B. Sitar,*3 P. Strmen,*3 K. Siimmerer,*2
T. Suzuki, I. Tanihata, M. Winkler,*2 K. Yamashita, and K. Yoshida[NUCLEAR REACTIONS; 40 Ar + Be, E "-' 1 A MeV; Secondary beams; (jI(12-20C)]
Measurements of the interaction cross-sections ((j I)at relativistic energies allow us to determine the nuclear matter radii because of the simple reaction
mechanism. 1) Since the nuclear radii are directly related to the density distributions, the measurements of(j I have been utilized to deduce the density distributions of some halo nuclei. Among the C isotopes , 19C
is one of the most interesting candidates for a neutronhalo nucleus. Its one-neutron separation energy (Sn)is the lowest (= 240 ± 100 ke V) among C isotopes.
The longitudinal-momentum distribution of lSC , after
the one-neutron breakup of 19C, has been measured
at 77 A MeV. 2) The observed narrow width of momentum for lSC indicates a one-neutron halo of 19C.
However, the density distribution of 19C has not been
determined till today. Therefore, measurements of (j I
are indispensable. Our experimental setup and experimental conditions are readily described in the previous
progress report. 3)
The (j I plotted as a function of the mass number(A) of the C isotopes are shown in Fig. 1. Observed (jI
increases monotonically with A. The solid line in the
figure shows the (j I calculated by the equation: (j I =11" [RI(C) + ToAl/3]2, where R1(C) is the interaction
radius of 12C and TO is a number selected to reproduce
the 12 C cross-section. The broken line in Fig. 1 showsa systematic increase obtained by simply fitting the (j Iof l7C, ISC, and 20C. Observed (jI for the 19C is muchlarger than the systematic trend by about three (j's.
Thus, an anomalous structure is evident for 19C.

For further quantitative discussions, we have performed calculations similar to those in Ref. 4. Matterdensity distribution of the core eSC) has been
parametrized to reproduce the observed (j] of lSC witha C target. The density distribution for the valence
neutron of 19C was calculated by a simple potential
model,4) where single-nucleon density distributions forthe s, p and d orbitals in a core plus nucleon potential were calculated for given values of the separationenergies. In the calculations, we assumed a WoodsSaxon shape potential; fixed the radius and diffusenessparameters; and we adjusted the depth of the potential so as to reproduce the Sn of 19C. The resulting
single-neutron distribution was added to the core density distribution, taking into account the difference inthe center of mass for the composite system. The spin
and parity of 19C are not known experimentally. If weassume J7r = 1/2+ for 19C, a 46% (54%) occupation
probability for the 0+ 0 2s 1/ 2 (2+ ® 1ds / 2) configurationis necessary to reproduce the observed (jI. The matterdensity distribution with the above mixed configurations is shown by the solid line in Fig. 2. Since the
distribution has a large tail component, a neutron halo
structure of 19C is clearly demonstrated in this figure.

~

0.1

:a

0.01

I

0.001

.~ 0.0001

~

1O.~

~

10-6

::E
1300

g

-:0

llOO

;

1000

10

.' :".

1200

r

,r

~.

900
800
700
8

10

12

14

A

16

18

20

22

Fig. 1. (J I for C isotopes on C targets. The filled circles
are data points obtained in this work. The blank circles
are data from previous studies at LBL.
*1 Kurchatov Institute, Russia*2*3

GSI, Germany
Comenius University, Slovak Republic

15

20

(fm)

Fig. 2. Density distributions of 19C based on a core plus
neutron structure. The dashed, and dotted lines show
the density distributions assumed pure 0+ 0 2s 1 / 2 andpure 2+ 0 1d 5 / 2 configurations, respectively. The solidline shows the density distribution required to reproduce the observed (JI for 18C and 19C.
References
1) 1. Tanihata et al.: Phys . Rev. Lett. 55, 2676 (1985).
2) D. Bazin et al.: Phys. Rev. Lett. 74, 3569 (1995).
3) A. Ozawa et al.: RIKEN Accel. Prog. Rep. 31, 79(1998).
4) M. Obuti et al.: Nucl. Phys. A 609, 74 (1996).

832. Atomic and Solid-State Physics

RIKEN Accel. Prog. Rep. 32 (1999)

Charge Transfer Processes in Collisions of H+ Ions
with P Atoms at Low Energies
J.-P. GU,*1 G. Hirsch,*l R. J. Buenker,*l M. Kimura,
C. M. Dutta, *2 P. Nordlander, *2 and 1. Shimamura
The use of heavy ions in radiation therapy is expected to provide an advantageous therapeutic effectfor tumors which are deeply seated and radioresistantprovided that an effective dose distribution can be
made. In particular, at the near end of the particle
track, a sharp Bragg peak is known to be present forheavy ions. This is one of their special features that is
considered to be most useful for treating tumors deep
inside the body. I) An efficient exploitation of this advantage of heavy ions in radiation therapy requires acareful treatment plan that enables one to concentrate
an efficient and sufficient dose to a target region andspare surrounding critical organs. Since phosphorus(P) atoms are abundant in human bodies, it is important to examine the collision dynamics by proton
impact. We have investigated charge transfer and excitation of P atoms in collision with H+ ions at lowto-intermediate collision energies based on a molecular expansion method. The processes in which we areinterested are shown below, together with the corresponding asymptotic energy defects.
(i) Ground - statePatoms :P(3s 23p 3 : 4S0) + H+ --t
P+(3s 23p2 : 3p) + H(ls) + 25099 cm- l(1)(ii) Metastable - statePatoms :P(3s 23 p 3 : 2DO) + H+ --t
P+(3s 23p2 : IS) + H(ls) + 14885 cm- l(2)

In the present CI calculations, the atomic orbital(AO) basis set employed for the phosphorus atomis (12s9p) contracted to [6s5p]. The basis set for
the hydrogen atom is a (7s3pld)/[5s3pld] contracted
set. The first step in the theoretical procedure is
to carry out an SCF calculation using the above
AO basis sets to generate MOs which are employed*1*2

as an orthonormal basis for a multireference singleand double excitations (MRD-CI) configuration interaction treatment. 2) A semiclassical MO expansion
method with a straight-line trajectory of the incident
ion was employed to study the collision dynamics below
10 keY /u. 3 ) The molecular states included in the dynamical calculations are the two sets of states: (i) quartet states, and (ii) doublet states. First we consider thecollision process (1). Below 1 keY ju, P+(3s 13p 3 : 5S0)state formation becomes a strong channel for chargetransfer although below 0.1 keY /u or so, 3 4r- statetakes over. Above /"VI keY ju, P+(3s 23p2 : 3p) is foundto be produced more efficiently, but as the energy decreases, P+(3s 13p 3 : 5S0) production dominates down
to 0.03 keY ju. Below this energy, P+(3s 23p2 : 3p)
production takes over again. Around I keY ju, bothproductions are comparable in magnitude. The production ofP+(3s 23p2 : 3p) peaks near I keV/u, but issmall in the entire energy range calculated here. For
the process (2), at higher energy, the 3 2r- state and
4 2r- radial coupling dominates, while as the energy
decreases, 2 2r- state and 4 2r- coupling takes overthe dynamics. In addition, 2 2r- state and 3 2r- radial coupling play some part at intermediate energy.
Naturally, charge transfer from the metastable atom
is much larger than that from the ground state in allenergies studied.
ReferencesI} Proc. NIRS Int. Seminar on the Application of Heavy
Ion Accelerator to Radiation Therapy of Cancer, Chiba,
1994-11, edited by A. Maezono (1994).
2) R. J. Buenker and S. D. Peyerimhoff: Theor. Chim.
Acta. 35, 33 (1974).
3) M. Kimura and N. F. Lane: Adv. At. Mol. Opt. Phys.
26, 76 (1989).

Theoretische Chemie, Bergische Universitat-Gesamthochschule Wuppertal, Germany
Department of Physics, Rice University, USA

85

RI KEN Accel. Prog. Rep. 32 (1999)

A Comparative Study of Electron- and PositronPolyatomic Molecule Scat tering
M. Kimura, I. Shimamura, O. Sueoka, A. Hamada,*1 and Y. Itikawa*2
The study of positron collisions with molecules has
a long history. Interest in positron-molecule collisions
arose from a study of positron annihilation in a molecular gas and its related subject, the slowing down ofa positron in a molecular gas. Due to rotational andvibrational excitation processes, molecules are more efficient than atoms for slowing down positrons, particularly at low incident energies. With a simple model,
rotational excitation cross sections for positron collisions with molecules were estimated and a significant difference between positron collisions and electron collisions in the process was demonstrated. We
briefly summarize the characteristics of the problem,
first in comparison to positron-atom collisions and thento electron-molecule collisions. The potential generated by a molecule is always anisotropic. Molecules
have electric multipole (i.e., dipole, quadrupole ,"')
moments. The interactions of an incident positronwith these multipoles are usually anisotropic and oflong range. This feature is one of the noticeable differences between the positron-atom and -molecule collisions. Molecules have rotational and vibrational degrees of freedom. If the interaction potential has astrong anisotropy, rotational motion can be easily excited. An anisotropic and long-ranged interaction between the incident positron and molecular multipoles
is very effective in the excitation of molecular rotation.
Molecular vibration is excited through the distortionof the electronic cloud of the molecule induced by thecollision with the incident particle. In this sense, vibrational excitation is more sensitive to the short range
part (i.e., near the molecular nuclei) of the interaction. Dissociation of a molecule can be regarded asa limit of vibrational excitation. In many cases the

*1

*2

86

Faculty of Engineering, Yamaguchi University
Institute of Space and Astronautical Science

dissociation products are active species (i.e., atoms andradicals). In this regard, the electron impact dissociation is of practical importance and has been studied
extensively. Information is rarely available, however,on positron-impact dissociation. In relation to the dissociation process, the following process is of particularinterest for a positron collision:e + + AB -+ A + + PsB.

(1 )This kind of Ps compounds are interesting objects inatomic physics. They offer another test of many bodytheory. A more challenging process is
e+ + AB -+ Ae+ + B.

(2)

Positron collisions with a Li-containing molecule could
give experimental evidence of such an exotic positiveion. It is unlikely for a simple molecule to capture a
positron and form a shape resonance. A large polyatomic molecule, however, may have the possibility tocapture a positron. A polyatomic molecule has multiple modes of vibration and the dependence on the
projectile may be different for different modes. For
the same reason , preferable dissociation channels in
the positron molecule collision may differ from thosein the electron molecule collision. The present study isconcerned more with polyatomic molecules than with
diatomic and triatomic molecules, which were mainly
treated in the earlier review article by Kauppila andStein. 1)
References
1) W. E. Kauppila and T . S. Stein: Adv. At. Mol. Opt.
Phys. 26, 1 (1989).

RIKEN Accel. Prog. Rep . 32 (1999)

Low-Energy Positron Collisions with CH4 Moleculeand Ar Atom
T. Nishimura and 1. Shimamura
Theoretical work on vibrationally-elastic scatteringof positrons (e+) from two kinds of targets CH 4 andAr is reported. The present theory is an extension of
the previous work on the e- + CH 4 collision. 1) In addition, the fact that the behavior of the differential crosssection (DCS) recently measured for the elastic process of e+ + CH4 2 ) is quite similar to that of e+ + Ar 3)
has stimulated our interest to study these processes
theoretically.
The present theory is based on the fixed-nuclei
approximation. 1) Then, the wavefunction of the scattered positron satisfies a set of coupled differential
equations derived from the Schrodinger equation for
the total collision system. By solving these equations,the scattering matrix is obtained from the asymptotic
form of the wavefunction, and is transformed into thecross sections. The interaction potential between apositron and a target is represented in the form of a
local potential which consists of the electrostatic andthe polarization potentials. As for the latter potential,
a model potential (veorr) which is based on the correlation energy of a positron in a homogeneous electron
gas4 ) is adopted for the smaller values of the positrontarget distance, r. This potential is connected withthe long-range asymptotic form (Vpol) of the dipole
polarization potential (ex r- 4 ) at the position of r = rewhere the two potentials v eorr and V pol cross eachother. Throughout the present calculation, no positronium (Ps) formation channel is taken into account at
collision energies of 0.2- 10 eV.
Figure 1 shows the vibrationally-elastic integral
cross sections (ICS) for the e+ + CH 4 and e+ + Ar systems as a function of the collision energy. Below the Ps
formation threshold (i.e., 5.80 eV for CH 4 and 8.96 eV
for Ar), the present ICSs for both CH 4 and Ar well
reproduce the corresponding experimental total crosssections (TCSs). 5 ,6) Qualitatively, the calculated ICS
for CH4 has a behavior which happens to be similar
to that of Ar in the low energy region of 0.2- 3 eV.
Quantitatively, however, they are quite different. The
difference mainly comes from the difference in the magnitude of the potential near r e , which in turn comesfrom the difference in the value of r e , that is, 3.24 au
for CH 4 and 2.85 au for Ar. Above the threshold for Ps
formation, the TCSs are not appropriate quantities tocompare with the present ICSs, since contributions of
Ps-formation cross section to the TCSs become rapidly
large.
Figure 2 shows the elastic DCS for e+ + CH 4 atenergy of 6 eV and for e+ +Ar at 5 eV, where theexperimental data are available. Since the measured
DCSs are on a relative scale, they are normalized at ascattering angle of 90° to those of the calculated DCS.
The shapes of the measured 2,3) and calculated DCSs
are seen to be similar to each other. Furthermore, wehave found similarites between the present DCSs of thetwo systems for energies of 3-10 eV, which can be attributed to an accidental similarity of the interaction
potential between the two systems; not in shape but inmagnitude. Further details will be reported elsewhere.

- - CH4: 6 eV (Present)
- - -

•

CH4: 6 eV (Exp.)

AI: 5 eV (Present)°

AT: 5 eV (Exp.)

100

120

~

o

.~
CIl

'" 0.1
Vl

~

<a
.~

e

~ 0.01

is

20

40

60

80

140

160

180

Scattering Angle (deg.)

- - -

!

Ar (Present)! It I I~.yoFig. 2. Differential cross sections of the elastic scatteringin the e+ + CH4 system at energy of 6 eV and in thee+ + Ar system at 5 eV.

6

CIl

4

References
1) T. Nishimura and Y. Itikawa: J. Phys. B 27, 2309

10

Collision Energy (eV)Fig. 1. Integral cross sections of the elastic scattering in
the e+ + CH 4 and e+ + Ar collision systems.

(1994).
2) D. A. Przybyla et al.: Phys. Rev. A 55, 4244 (1997).
3) S. J. Smith et al.: Phys. Rev. Lett. 64, 1227 (1990).
4) E. Boronski and R. M. Nieminen: Phys. Rev. B 34,
3820 (1986).
5) O. Sueoka and S. Mori: J. Phys. B 19, 4035 (1986).
6) W. E. Kauppila et al.: Phys. Rev. Lett. 36, 580 (1976).

87

RIKEN Accel. Prog. Rep. 32 (1999)

Close Coupling Calculation for e + Ps Scattering
A. Igarashi
Nowadays the positronium beam has become available , and the collision experiments with protons,
atoms, and molecules have been reported. I)
Since the positronium consists of two particles withthe same mass and opposite charge, the static potential between a positronium and a collision partner vanishes. Therefore, the main interactions in the e + Ps
scattering are the electron exchange and polarization.
We apply the usual close coupling or coupled channel method to the e + Ps system, and the integrodifferential equations for radial functions are solved
with a B-spline method. B-spline function is a piecewise polynomial, which is easy to handle and is quite
flexible to interpolate a function. Some applicationsof the B-spline function in atomic physics are found in
Ref. 2.
The total wave function of the Ps- system is expanded in terms of B-spline functions in the radial
range of 0 ::::; R ::::; Rmax(R = RI or R 2) as

and five d orbitals and (iv) 27 states: ten s, nine p andeight d orbitals. The results are tabulated in Table 1
for S- and P -wave phase shifts for some total energies
below the Ps(n = 2) threshold. The variational calculation by Ward et al. 3) is also included for comparison.
It is clear that the present phase shifts with basis setsof 18 states and 27 states show good convergence andthey are in agreement with the variational values.
To end, the close coupling method was successfully applied to the calculation of the e + Ps scattering
phase shifts. This method will be extended to calculatecomprehensive cross sections in the e + Ps scattering.
Table 1. Phase shifts in e + Ps scattering at collision
momentum k (a.u.) for the symmetry 25+1 L .

k

1 state 3 state

18 state

27 state

Ward et aI. 3)

2.049

0.1

1.655

1.860

2.056

2. 056

0.2

0.988

1.166

1.378

1.378

1.378

0.3

0.585

0.761

0.983

0.983

0.984

0.4

0.320

0.508

0.746

0.746

0.748

N

W=

L LCf(Bi(RI)¢JL(rllRd

JL = Ii+( _1)5 B i (R 2)¢JL(r2, R 2)) =:L Cr BJL ,i, (1)

3S

JL ,t

where rl (r2) is the position vector of electron 1 (2)from positron, RI (R2 ) the position vector of the otherelectron from the center of mass of positronium of
positron + elecron 1 (2), Bi the B-spline function, ¢JL
the atomic base, S the total spin of two electrons, N
the number of atomic basis functions, andis anexpansion coefficient. Rmax should be chosen as large
as the exchange coupling can be neglected.
From < Bv,j IH - Elw >= 0, the homogeneous algebraic equation for the row vector c =: {Cf} is givenasCrAc = 0, (A)iljl = < BJL ,iIH - EIBv,j > .

(2)

In the above equation, N independent solutions of c,that is, N independent sets of radial solutions can befound for 0 ::::; R :S Rmax. Because the radial equations
are of local potentials for R I , R2 > R max , they can besolved forward direction in the usual manner. Asymptotic radial solutions are matched with the scatteringboundary condition, and hence the scattering matrix
is extracted.
Four different Ps-basis sets of real states or Sturmian
functions are considered here as following; (i) 1 state:Is, (ii) 3 states: Is , 2s, 2p, (iii) 18 states: seven s, six p,

88

0.1

-0.570-0.538-0.536-0.536-0.5360.2-1.064-1.037-1.033- 1.033-1.0350.3-1.457- 1.437- 1.430-1.430-1.4320.4-1.761-1.745-1.736-1.736-1.739-0.038Ip
0.1-0.058-0.042-0.038-0. 0380.2-0.264-0.241-0.235-0.234-0.2350.3-0.498-0.474-0.463-0.463-0.4630.4-0.682-0.652-0.634-0.634-0.635

3p
0.1

0.107

0.166

0.192

0.192

0.192

0.2

0.476

0.628

0.707

0.707

0.707

0.3

0.586

0.699

0.778

0.778

0.778

0.4

0.519

0.608

0.687

0.687

0.687

References
1) A. J. Garner et al.: J. Phys. B 29 , 5961 (1996); J. P.
Merrison et al.: Phys. Rev. Lett. 78, 2728 (1997) .
2) Many-body Theory of Atomic structure and Photoionization, edited by T. -N. Chang (World Scientific, Singapore, 1993).
3) S. J. Ward et al.: J. Phys. B 30, 127 (1987) .

RIKEN Accel. Prog. Rep. 32 (1999)

Protonium Formation in p-H Collisions
R. J. Whitehead, J. F. McCann, and I. Shimamura
The existence of long-lived antiprotons p in liquid helium!) was explained 2 ) by the existence ofmetastable atomic states of antiprotonic helium He+p
where p is captured into high-n, high-l orbitals. The
subsequent decay and annihilation processes of He+p
are fairly well understood. 3 ,4) However, the details of
the capture process are less well known. 5) In this work
the classical-trajectory Monte-Carlo (CTMC) method
has been used to determine ionization and capture
cross sections for collisions between p and atomic hydrogen H. The results we obtain are an improvement,in terms of accuracy and statistical error, on previous
work. 6) For p capture (or the production of protoniumpp) the nature of the orbit can be characterized by thequantum numbers (n, l) obtained through the correspondence principle 7) by relating the classical energy
and angular momentum to the corresponding quantum
numbers. We present some of our results which indicated the pp distribution over the n.
Cross sections for p- H collisions are presented inFig. 1. For ionization, the results near the peak
(ECoM ~ 0.65 a.u.) are substantially higher thandata previously obtained by CTMC simulations. 6) The
p capture cross section rises steeply below the collisional ionization threshold. We have found that thelow-energy capture cross section curve can be represented accurately by the Langevin formula 8 ): (J =1
7r (20:/ E) 2. A numerical fit to the data found a valueof 0: ~ 0.15, substantially less than the static polarizability of the hydrogen atom. In comparison with thedata of Cohen,5,6) our results predict capture cross sections to be slightly larger, though the overall trend isvery similar. In order to reduce the statistical error tovalues smaller than the size of the data points plotted,
we used typically 5000- 50000 trajectories to construct

8

•~
I

~

;j

~
b

6

r::
.9
....

4

a

\
\

§\

0

V'J
V'J
V'J

E= 0.05

,.--,

~ 4

~

b

r::
.9
t)
0

V'J
V'J
V'J

E=0.1
3
2

a

U
0

20

30

40

50

60

70

Captured quantum number, n

2. Partial cross sections Un for pp formation in
15 + H collisions. E attached to each curve is the cen-Fig.

ter-of-mass collision energy in a.u.

The results show that pp is formed in high-n, highl orbits in support of the Condo hypothesis 2 ) and inagreement with the conclusion obtained by Cohen. 5,6)
This work was supported by the British Council and
the Japan International Science and Technology Exchange Center .
References
1) M. Iwasaki et al.: Phys. Rev. Lett. 67, 1246 (1991).
2) G. T. Condo: Phys. Lett. 9, 65 (1964).

\, Capture
"-

;-"~
9 ".,

Ionization

o'*-

2

5

I
I

~

u

each point.
Displayed in Fig. 2 are cross sections for pp formation in different shells ((J n). These distributions indicated the tendency towards high n, a result consistent
with classical capture from large impact parameters.
Comparison with results obtained by Cohen 6) for the
average value of n when capture occurs shows good
agreement. However, the results for the l-distributions
show significant differences. In particular, we find that
our simulations predict larger populations for high-l
states.

~I

U
Collision energy, ECoM [a.u.]

Fig. 1. Capture (.) and ionization (.) cross sections
for p + H ' collisions as functions of the center-of-masscollision energy. 0: Cohen's results. 6 )3) V. 1. Korobov and D. D. Bakalov: Phys. Rev. Lett. 79,
3379 (1997) .
4) V. 1. Korobov and 1. Shimamura: Phys. Rev. A 56 , 4587
(1997).
5) J. S. Cohen: Electromagnetic Cascade and Chemistry of
Exotic Atoms (Plenum Press, New York, 1990).
6) J. S. Cohen: Phys. Rev. A 36, 2024 (1987).
7) R. E. Olson: Phys. Rev. A 24,1726 (1981).
8) Y. Kaneko: in Molecular Processes in Space, edited
by T. Watanabe, 1. Shimamura, M. Shimizu, and Y.
Itikawa (Plenum Press, New York, 1990) , p. 117.

89

RIKEN Accel. Prog. Rep. 32 (1999)

Time-of-Flight Mass Spectroscopy of Product Ions
in Fast Ion-C 6o Collision
Y. Nakai, T. Kambara, A. Itoh, H. Tsuchida, and Y. Yamazaki
A number of measurements of the C 60 ionization andfragmentation have been performed by using various
excitation probes (photon, electron, ion etc). The intensity distributions of product ions strongly dependon the internal energy of precursor of fragmentation.
We have reported that only a multiple fragmentation
occurs in the hard collision by fast heavy ion. 1) On theother hand, in the case of lower excited energy by electron impact or by very low energy collision with atomand surface, C 60 emits a small neutral carbon cluster in the micro second time scale after excitation. 2,3)
In these cases, the internal energy can be estimatedby comparing the experimental intensity ratio between
the C 60 ion and the fullerene-like fragment ion with thetheoretical one.
The time-of-flight (TOF) peak profile of each product ion has information of the initial kinetic energy,
reaction rate coefficient of fragmentation, and so on.
However, a part of such information is often lost because of the poor experimental resolution of TOF
measurement. We intend to collect such information by applying a high-resolution TOF mass spectroscopy. The Wiley-McLaren's spatial-focusing condition was used for the TOF measurement. The beams of
2.5 MeV lu He 2+ and C6+ were accelerated by RIkenLinear-ACcelerator(RILAC) and collimated upstreamof the target of C 60 vapor. The C 60 target was prepared by evaporating the commercial C 60 powder ina temperature-controlled oven. The effusive C 60 was
collimated by a slit located below the collision region. Base pressure in the collision chamber was kept
below 2 x 10- 8 Torr. The electrons extracted fromcollision region were used to trigger the TOF measurement. The ion detector was a three-stage multichannel plate (MCP) and the electron detector wasa two-stage MCP. Each detector has an impedancematched anode for a fast timing read-out. TOF spectra were obtained using a multi-hit time-to-digital conions
verter (TDC). In Fig. 1, the peaks of TOF ofare shown. Each peak is corresponding to C60 , whichcontains the different number of 13C. We can separate the peak with 720 amu(12C 6o ) and from thet with
721 amu(12C 59 13 C).We suppose that the reason for ourhigh resolution is due to the good collimation of ion
beam and the C 60 molecular beam, and a fast timing
readout.
In Fig. 2, the TOF-peak of Ct8 produced by the
2.5 MeV He 2+ impact is shown. This peak has an
asymmetric shape. This asymmmetric shape does notcome from the mass difference in C60 with different
number of 13C. As shown in Fig. 1, the thermal motionof C 60 target does not cause such a broad peak of Ct8'
In Fig. 2, we show the TOF-peaks obtained by Monte
CaIro simulation for--t Ct8 +C 2 with a certain lifeof fragmentation (0.0 f-lsec and 2.0 f-lsec) and a 0.4 eV
kinetic energy release. In the case of 2.0 f-lsec, the

cto

cto

90

300000Experiment I

I
250000C +60m=720amu
200000~ m:121~"V)

c::> 150000
0U!~~ m:722~".~~

100000

50000

...J
10080

.

/\

101 20

10100

10140

TOF (ns)cta

Fig. 1. TOF-peaks ofions are shown. Each peak iscorresponding to C 60 which contains the different number of 13C. The width of each peak is considered to bea resolution of our system.

Hfe = O.OI1S KER = OAeV-.. .. •. .. Hfe = 2.01LS KER = OAeV•

200

Experiment

150

c:'"

is 100U

50

I';,~~".. "/:.,~.:•.... ".. ..
;

13850

13900

13950

14000

14050

14100

14 15014200

TOF (ns)Fig. 2. TOF-peak of cta ions is shown. Solid circle
is experimental data. Solid line is the result of Monte
CaIro simulation with the fragmentation life of 0.0 Jlsec.
Dashed line is the result of Monte CaIro simulation withthe life of 2.0 Jlsec. In the case of 2.0 Jlsec, the simulation result also shows the asymmetric tail on the sideof longer TOF similarly to the experimental result. A
huge jump of experimental data at the later TOF is arise of

12cta'

simulation result also shows a symilar asymmetric tailon the side of longer TOF as observed by experiment.
This means that Ct8 is mainly produced in the delayedemission of C 2 from excited
We are continuing theanalysis of the data now.

cto.

References
1) Y. Nakai et al.: J. Phys. B: At. Mol. Opt. Phys. 30,3049 (1997).
2) M. Foltin et al.: J. Chern. Phys. 107, 6246 (1997).
3) P. Weis et al.: J. Chern. Phys. 104, 6246 (1996).

RIKEN Accel. Prog. Rep. 32 (1999)

Sub-State-Selective Differential Cross Sections ofElectron Capt ure in 1 0 MeV Ar 8 + - He Collisions t
T. Kambara, M. Kimura, Y. Awaya, Y. Nakai, T. M. Kojima, V. Mergel,* and H. Schmidt-Bocking*We have studied the electron capture processes,
using atomic target and highly-charged heavy ions,through measurements of the final-state-selective differential cross sections. Constituents of the collision
process investigated here are an Ar 8 + ion and a He
target and the reaction is:

Ar8 +(1s22s 22p 6 ) + He(ls2) -+Ar7 +(1s22s 2 2p 6 nl) + He+(n'l').

(1)

Here the projectile (Ar 8 +) energy used was 10 MeV
which corresponds to a velocity of 3.17 atomic unit(au). Since an Ar 8 + ion has a neon-like electron configuration, the electron can only be captured to then = 3 or higher orbital. We have measured the longitudinal momentum (parallel to the projectile momentum) PIIR and the transverse one PJ..R of the recoil
He+ ion applying the cold target recoil ion momentum spectroscopy (COLTRIMS)l) in coincidence withthe projectile which captures one electron. To obtain P J..R dependent differential cross sections of theelectron capture to different final states, we fitted the
PI I R distributions in different P J..R regions by a sumof Gaussian peaks which correspond to the final statesof n = 3-5. We have described the measurements andhave presented the differential cross sections dO" I dp J..Rof electron capture to the n = 3-5 states, previously.2)
A peak-fit analysis of the n = 3 final state yields therelative differential cross sections to the substates ofn = 3: i. e., 3s and 3p. The results are shown in Fig. l.
The experimental cross section to the 3d state is not

C\I--:;'"

Co 0.1

I
I 2Q

U
Q)

f ------- -~- -2--- ~- -"'"

Cf)

en
en

i

e 0.0
()

~

""""

:...............~ ............................... j', 2

:s::
(5

Exp. Theor.
3s •
3p 0
3d

~

.

1
234
Transverse Momentum (a.u)

Fig. 1. Differential cross sections of electron capture ton = 3 substates. Symbols denote the experimental results for 3s and 3p, and lines are the calculation results.

shown in the figure since the relative uncertainty ishigh, although it was included in the peak-fit analysis.
The experimental results of the differential crosssections are compared with calculations of the closecoupling approximation based on a molecular representation. We have employed the configuration interaction (CI) method to obtain molecular electronic
states of the collision system. 3 ,4) The pseudopotential
method was adopted to represent Ar 8 + core, because
it enables us to reduce the many-electron system tomore tractable two-electron system. The Slater-type
orbitals were used to construct the basis sets, andSlater exponents were given before. 3 ) The present levelof precision of all electronic states considered is lessthan 2 % compared with experimental asymptotic levels. All states corresponding to Ar 7 + (n = 3, 4 and
5; l ::; n - 1) were obtained. The series of avoided
crossing between the initial Ar 8 + IHe channel and thefinal Ar 7 +(n = 5)/He+, Ar 7 + (n = 4)/He+, and Ar 7 +(n = 3)/He+ levels takes place around 8, 7 and 5.5 au,
respectively. These crossings playa key role for capture processes depending upon the collision energy.
The calculated 3l (l = s, p and d) substate dependence of the capture cross section is compared withthe experiment in Fig. 1. Because of diabatic natureof the curve-crossing for higher l partial states with
the initial channel such as d and f states, capture to p
state is found to be generally dominant, and then followed by d state. For Ar 7 +(n = 3) formation, capture
to the p state is larger than sand d states by a factorof two. There are some differences between the theory
and experiment in details; but the theory is in a reasonable accord with the measurement, thus providing
a rationale to the observation.
References
1) J. Ullrich, R. Moshammer, R. Dorner, O. Jagutzki, V.
Mergel, H. Schmidt-Backing, and L. Spielberger: J.
Phys. B: At. Mol. Opt. Phys. 30, 2917 (1997).
2) T. Kambara, Y. Nakai, T. M. Kojima, V. Mergel, H.
W. Schmidt-Backing, and M. Kimura: RIKEN Accel.
Prog. Rep. 31, 90 (1998).
3) M. Kimura and R. E. Olson: Phys. Rev. A 31, 489(1985).
4) M. Kimura and N. F. Lane: in Advances in Atomic,
Molecular and Optical Physics, Vol. 26 (Academic Press,
1989) p . 79.

Condensed from the article in J. Phys. B: At. Mol. Opt.
Phys. 31, L909 (1998)
Institute for Nuclear Physics, University of Frankfurt,. Germany91

RIKEN Accel. Prog. Rep. 32 (1999)

Effects of the Ion Beam Energy on Atomic Lifetime Measurements
Using the Techniques of Beam-Foil Spectroscopy
R. Hutton, Y. Zou,*l S. Huldt,*2 I. Martinson,*2 K. Ando,
T. Kambara, H. Oyama, and Y. Awaya
In a previous article l ) we have discussed possible inherent problems with atomic life time measurements
using the beam-foil technique. These problems are related to contamination of spectral lines by satellite line
decays. As an example ·we have chosen to study the
decay of the 1s22s 2Sl/2-1s22p 2Pl/2,3/2 Li-like transitions. The satellite line contamination will then befrom Be-like lines of the form 1s22snl- 1s22pnl. In
Ref. 2 the fact that for some value of n (dependingon the atomic number, Z, of the ion) such configurations will go above the 1st ionisation limit of the Lilike ion is mentioned. For higher n levels these satellites will become less troublesome with regard to Li-likelifetime measurements due to the open autoionisation
channels. Another way to minimize the effect of thesesatellites is to choose the beam energy so as to minimize the Be-like charge state fraction of the ion beam
while maintaining a usable Li-like beam fraction. In
a recent study of the 1s22p 2p levels in Li-like Mg
this model was studied by choosing suitable beam energies. Beams of Mg ions were obtained from the RILAC at the energies of 0.4, 1.3 and 2.5 MeV lu. The
calculated charge state fractions for Li- and Be likeions at these energies are shown in Table 1 (the tables of Shima et al. 3) are used here). At the highest
energy used the satellite contamination should be verysmall and we would expect almost no contamination of
the Li-like resonance line. On the other hand for the
0.4 MeV lu ions we would expect a large satellite contamination, and hence decay curves measured at thisenergy to be inconsistent with theoretical predictions
Table 1. This shows the charge state distribution for Liand Be-like Mg ions after stripping by a foil at the energies of 2.5, 1.3 and 0.4 MeV lu.
Ion

E
MeV/u

Mg

2.5
1.3
0.4

Be-likepercent
0.8
1517Li-likepercent
15
42
3

BelLi ratio
0.053
0.357
5.67

*1 Applied Physics Department, Shanghai Jiaotong Un iversity,.2

92

P. R. China
Department of Physics, University of Lund, Sweden

for the 1s22p 2p level lifetimes. In Fig. 1 the decay of
the 2p 2P3/2 level is shown for the three beam energies
used. It is clear that the decay curves differ. The
date recorded at 0.4 MeV lu decaying faster than thatat the higher energies. This would appear to confirm
the satellite contamination model as discussed above.
More experiments are being performed with other Lilike ions.

,-..,

C/"J
.....
'2 10 1
~
9

.e

~

8
7
6

~

.<;:::
C/"J

s::
d)
.....
s::

OAMeV/u

10° '---~-~-~-~---'

0.0

0.8

l.6

2.4

3.2

4.0

Time (ns)Fig.
1.
Decay curves for the Li-like Mg 1s 22s
2S1/2-1s22p 2P3/2 transition recorded at three different
beam energies, 2.5, 1.3 and 0.4 MeV lu. The decay constant obtained from the 2.5 MeV lu measurement agrees
with the theoretical lifetime for the 2p 2P 3 / 2 level.
References
1) R. Hutton et al.: RIKEN Accel. Prog. Rep. 31, 94(1997).
2) R. Hutton et al.: RIKEN Accel. Prog. Rep. 32, 94(1998) .
3) K. Shima et al.: NIFS-DATA-lO, 1991.

RIKEN Accel. Prog. Rep. 32 (1999)

Beam Foil Spectroscopy of Highly Charged Erbium
R. Hutton, Y. ZOU,*I S. Huldt ,*2 1. Martinson,*2 K. Ando, T. Kambara, and H. Oyama
Using the techniques of beam-foil spectroscopy at
the RILAC we have begun a study of highly-charged
very-heavy ions. The reason for these studies is theinterest in fusion plasma diagnostics. I) It is expectedthat Xe (Z = 54) gas will be injected into the ITER
fusion device as a diagnostic element. As it has 54 electrons in the neutral atom and as the last electron has
a high ionisation energy, it should give rise to useful charge states throughout the plasma (Le., different ionic stages appearing at many different temperatures). Also it may be that W (Z = 74) will be used
as a material in the construction of the ITER device.
However the spectroscopy of these elements in many of
the charge states is relatively unknown. For a numberof charge states, however, the spectroscopy is expected
to be relatively simple: e.g., the Cu- and Zn-like charge
states. The Cu-like system is effectively a 1 active electron system and the Zn-like system a 2 active electron
system. Wavelengths for the resonance lines in these
two sequences are already known from laser produced
plasma experiments. However, some of the problems
in investigating spectra of these elements can be understood from Fig. 1. This shows beam-foil spectra of
1.5 MeV lu Er (Z = 68) taken at two different foil positions. Although Erbium is not of interest to ITER
diagnostics it was a convenient element to study interms of accelerator beam currents etc. The results canof course be compared in an isoelectronic way with Xeand W. The spectrum taken where the foil is very close
to the spectrometer entrance slit shows a multitude oflines and it is an almost impossible task to identify any
single feature. However, as a time delay is introduced
between the foil excitation and the observation windowa group of quite well resolved lines becomes apparent,
see Fig. 1. Closer study shows one of these lines infairly good wavelength agreement with a calculation of
the Zn-like intercombination line (4s 2 I So - 4s4p 3 PI)
by Beimont. 2) We subsequently measured decay curves
for this group of lines by recording light intensity as
a function of foil position. In particular, the intensity
decay of the line corresponding to the calculated wavelength of the 4s4p 3 PI level decay was analyzed. A decay curve was constructed from which a lifetime for the
4s4p 3 PI level was obtained. A decay time of around1 ns was found for this line. However in previous reports we have discussed problems related to satellite

*1
*2

350

250

150

(b)
40

100

200

300

Wavelength, A
Fig. 1. This shows beam-foil spectra recorded using abeam of 1.5 MeV lu Erbium . The two spectra are taken
at different foil positions: (a) very close to the foil and(b) with a time delay of around 0.25 ns between excitation and observation.

line contributions to spectral lines and the influenceof such satellites on lifetime measurements. 3 ) In particular we have shown a shortening of measured decay
times compared to theoretical counterparts due to thesatellite contamination. In the experiment done here
we expect satellite contamination to be quite large , andtherefor our experimental decay time should be shorter
than the true level lifetime. However, the theoretical
lifetime given in Ref. 2 is 86 ps which is already shorter
than our measured value. The only conclusion we candraw at this moment is that more investigation, boththeoretical and experimental, is called for.
References
1) F. W. Meyer: Comments At. Mol. Phys. 33, 193 (1997).
2) E. Biemont: At. Data Nucl. Data Tables 43, 163 (1989).
3) R. Hutton: RIKEN Accel. Prog. Rep. 32, 94 (1999).

Applied Physics Department, Shanghai Jiaotong University,
P. R. China
Department of Physics, University of Lund, Sweden

93

RIKEN Accel. Prog. Rep. 32 (1999)

Continued Studies of the Beam-Foil Technique for Atomic
Lifetime Measurements Using Li-like Ne
R. Hutton, Y. ZOU,*1 S. Huldt,*2 1. Martinson,*2 K. Ando, T. Kambara, and H. Oyama
In a previous report we have discussed problems
which arise due to satellite contamination of spectral lines in beam-foil spectroscopy and in particular,
the influence on lifetime measurements using the Lilike resonance lines of Ar as an example. 1) There, we
showed that at the beam energy used (2.5 MeV lu) the
decay of the Li-like Ar resonance line could be contaminated by Be-like satellite line decays. The role thebeam energy plays in such measurements is describedin Ref. 2. In this report we will describe an experiment
to measure the Li-like resonance line lifetime for Neon.
It turns out that only a few satellite lines can affectthe decay of the resonance line. This is due to (a)wavelength considerations, i.e. the satellite line must
blend the transition of interest, also (b), lifetime considerations, i.e. if the initial state of the satellite level
decays with a rate very much faster than the excitedstate giving rise to the resonance line , then the effectis small. The upper satellite level in the cases studied
here is 2pnl and this configuration will go above the18 228 ionisation limit for some value of n. Once theinitial state of the satellite line is above the ionisation
limit, very fast autoionisation channels become open
for many of the levels of the 2pnl configuration. Thisis shown graphically in Fig. 1, where the n value forwhich the 2pnl configuration goes above the 18 228 ionisation limit is shown as a function of Z. From Fig. 1
we see that already for n = 7 the 2pnl levels go above
the ionisation limit for Ne. However the 2p61levels are
predicted (Cowan code calculations)3) to decay quite
fast (at least a factor of 10 faster) compared to the
decay of the ls22p level, and therefore the effect of thesatellite contamination on the resonance line lifetime
may be minimal. To test this we recorded decay data
for the Li-like N e resonance lines. The lifetimes forthese levels have been measured in a previous work by
Knystautas et al. 4 ) In Fig. 2 we show a decay curvefor the stronger of the the two resonance lines, the281/ 2 - 2P3/2 transition. We paid particular attention
to recording many points close to the foil zero position as it is in this region that deviations from a single
exponential decay can be expected. We found, however, a single exponential decay with a decay constantmatching the theoretical lifetime of the 2p 2P3 / 2 level.
This is in agreement with the model described above
and in Ref. 1.

*1
*2

94

Applied Physics Department, Shanghai Jiaotong University,
P. R. China
Department of Physics, University of Lund, Sweden

12

10

6

4

2~--~--~--~--~~

o

15

45

30

60

Z

Fig. 1. This shows the value of n in 1s22pnl for which
autoionisation becomes energetically allowed as a function of Z for Be-like ions. The value of n was obtained
from calculations using the Cowan computer code.

Decay of the 2P3/21evel in Li·like Ne

C

.~

~
.~
~

10'

,

.
1

,

0.5

1.0

2.0

2.5

).0

Time after excitation. ns

Fig. 2. This shows the decay curve for Li-like Ne measured
at a beam energy of 0.4 MeV lu. The decay curve is astraight line, (on a log scale), showing that the decay isprobably not contaminated by satellite transitions.

References
1) R. Hutton et al.: RIKEN Accel. Prog. Rep . 31 , 94
(1998) .
2) R. Hutton et al.: RIKEN Accel. Prog. Rep. 32, 93(1999) .
3) R. D. Cowan: The Theory of Atomic Structure andSpectra (University of California Press, Berkeley, 1981).
4) E. J. Knystautas et al.: J. Quant. Spectrosc. Radiat.
Trasfer 11, 75 (1971).

RIKEN Accel. Prog. Rep. 32 (1999)

Foil Ageing Problems in Beam-Foil Spectroscopy
R. Hutton, Y. Zou,*l S. Huldt,*2 I. Martinson,*2
K. Ando, T. Kambara, and H. Oyama
The target in beam-foil spectroscopy is often a thincarbon foil with a thickness of between 2 and several
hundred microgramms per square cm. The status of
the foil is very important to the photon generation by
the subsequently decaying foil excited ions. In the extreme case of a foil with holes both the current, measured in a Faraday cup (for normalizing the measurement time), and the light yield in a particular line will
decrease, and not necessarily in a proportional way.
In a series of beam foil spectroscopy experiments performed at RILAC, foils with thickness of either 10 or
40 J.tg/cm 2 have been used. It was considered that
1 hour exposure to the beam would be sufficient to
prepare the foil for stable use. However, we have foundthat the foil actually never really stabilizes, or that it
does so after more than 20 h which was the longest
time we have ever used a single foil. In measuring
lifetime decay curves for foil excited ions we chose afixed foil position to measure the foil aging properties.
That is the foil was returned to a fixed slit-foil separation every 1 or 2 h and spectra were recorded. We
found that the foil aging property depends on bothbeam energy and the ion species passing through thefoil, and maybe, to some extent, on the type of foilused. We have little data here, so this needs further
investigation. Foil aging properties are shown graphically in Fig. 1. In Fig. 2 we show the effect on the
spectra at two quite different times, i.e. after 2 hand
after 10 h. The beam used here was Mg at an energyof 2.5 MeV lu. The charge state before the foil was
Mg6+. It can be seen that not only the intensity but
also the charge state distribution changes. The more
highly charged ions, e.g. He-like Mg, becoming relatively more predominant at longer times, given thatthe light intensity from a given charge state follows the
charge state fraction in the beam. This may require
the ionisation and excitation processes in the ion-foil
interaction to be similar which need not be true . These
effects can be of course taken into account when measuring lifetimes using the beam-foil method, but suchcorrections are not often discussed in the literature.

*1*2

2.5 MeV/u Mg

6

8

10

12

14

16

18

20

Foil age in hourFig. 1. The measured photon intensity in one of the Li-likeresonance decays for different beams plotted as a function of the time after which the foil was first exposed tothe ion beam. Here, "foil age in hours" means the number of hours after the foil was first exposed to the ion
beam. The data was recorded with foil-spectrometer
slit separation of around 2 mm.
205 r----~--~-----~------,a

10 hours
c

200

195

.~.

190

§ 185

.5 180175

170
165 L -_ _
605

~

610

__

~

615

_

_

~

__

620

~

_ _- - '625

630

Wavelength, A

Fig. 2. This shows that the photon intensity in Li-likelines decreases with time after the foil is first exposedto the beam, whereas the photon intensity in He-like
transitions increases. The two spectra are recorded ata fixed foil position 2 and 10 h after the foil was exposedto the beam. The two Li-like 2s-2p resonance lines areat 609.5 (a) and 624.5 A (c). A feature from high nl
He-like lines is seen at around 618 A (b).

Applied Physics Department, Shanghai Jiaotong University,
P. R. China
Department of Physics, University of Lund, Sweden

95

RIKEN Accel. Prog. Rep. 32 (1999)

Crossed Beam Experiment of Highly Charged Ion-Atom
Collision in the Energy Range below 100 eV /q
M. Kitajima, Y. Nakai, Y. Kanai, Y. Yamazaki, Y. Awaya, and Y. Itoh
The study of multi-electron capture processes inthe slow collisions between highly charged ions andatoms or molecules has been the subject of considerable experimental and theoretical investigations. Recently, experimental techniques utilizing a recoil ion
source for producing very slow ion beam for the angular differential cross section measurements have beenpresented. 1 ,2) The intensity of the very-slow ion beamis, however, extremely small and species of the ions arelimited for these experiments.
Here we present an experimental setup for measurementts of the state selective angular differential
cross section of multi-electron capture processes in thevery-slow collisions between highly charged ions andatoms or molecules. It utilizes the ion beam fromthe 14.5 GHz Caprice electron cyclotron resonanceion source (ECRIS) at RIKEN. 3 ) Using the direct ion
beam from the ECRIS has the advantage to achievea high-intensity beam, even after the deceleration of
the ion beam. Highly charged ions produced in the ion
source are extracted at a beam energy of 2 ke V / q into
the beam line, and then the mass to charge ratio (mlq)
is selected with an analyzing magnet. The ion beam
is decelerated down to desired energy in two steps using deceleration lens and energy selected by a double
hemispherical analyzer. The target gas is introduced
by a multi capillary and intersects with the ion beamat right angles. Scattered ion energies are analyzed bya hemispherical analyzer, which is set on a turntable.
Typical currents of the ion beam measured rightafter the mlq selection (2 keY Iq) and those at theintersection region (decelerated beam) are shown in
Table 1. The intensity of very-slow ion beams obtained in the present ECRIS setup is much higher thanthat obtained with the recoil ion source by a factor of
10 4 . An overall energy resolution of about 1/180 of thebeam energy was achieved in the present apparatus.
Table 1. Currents and energy widths of ion beams obtainedin the present experimental setup.
Ions 2ke V /q b eam Decelerated b eam Beam ene rgy Ene rgy width(J.£A)(pA)(eV /q)(eV jq)
Ar 8 +
13
22
0.20
35
Ar 6 +
300
0.27
9
50
Ar4+
3
135
60
0.66
He 2 +
20
250
0.58
70
He+
10
300
0.33
60
He+
30
180
40
0.33
He +
20
7
20
0.18

96

The energy distributions of scattered ion in the36.6 eV Iq (7.3 eV lu) Ar8 + -N2 collisions at the scattering angles from 0° to 10° are shown in Fig. 1. The
intense peak seen at 44 e V I q for Lab = 0°, originatingfrom single electron capture, rapidly decreases with increasing the scattering angle. The neighboring peak at
46 eV I q also decreases at larger angles. At 53 e V I q,a multi-component peak due to the double electron
capture processes is seen, the intensity of which decreases rather slowly. The peak at 56 e V I q does notdecrease its intensity with scattering angle in contrast
to the other peaks. These different scattering angle
dependencies confirm the fact that single electron capture occurs mainly in the glancing collisions with small
scattering angle. On the other hand, multiple electron
capture occurs in the close collisions with large scattering angle.

e

40

50
Energy (eV/q)

60

Fig. 1. Energy distributions of scattered ion (Ar 8 +, Ar 7 +,and Ar 6 +) in the 36.6 eV Iq (7.3 eV lu) Ar 8 + -N2 collisions at the scattering angles () Lab as indicated.

References
1) H. Cederquist et al.: Phys. Rev. A 39, 4308 (1989).
2) S. Yaltkaya et al.: Phys. Rev. A 48 , 382 (1993).
3) Y. Kanai et al.: Proc. 12th Int. Workshop on ECRIS,
edited by M. Sekiguchi and T. Nakagawa, INS-J-182(Tokyo, 1995), p. 312.

RIKEN Accel. Prog . Rep. 32 (1999)

Angular Distribution of Auger Electrons from Doubly-Excited
N 3 + Produced by the 50 ke V N 5 +-Ar Collisions
T. Kamei, K. Ogura, T. Takayanagi, K. Wakiya, Y. Kanai, and Y. Nakai
To study the double-electron capture processes ofhighly-charged ions, we have measured Auger electrons emitted from Be-like doubly-excited states. 1 ,2)In some collision systems, the Auger electron intensities from triplet states were predominant in the spectra
measured at 0° .1,2) To comfirm that the triplet states
are indeed produced dominantly in those collision systems, we need the Auger spectra over the whole angular range in the scattering plane. This is because
the angular distribution of ejected electrons from multiply excited states produced by the multiple electron
capture from target atom is strongly anisotropic.
Here we present the spectra of Auger electrons
from the doubly excited N3+**(1.~3l3l'), which were
measured at different observation angles by using a
toroidal-type electron energy analyzer. 3 ) These states
were produced by the double-electron capture processes in the collision of the 50 ke V NS+ ions withAr atom. The 50 ke V NS+ ions were extracted fromthe 14.5 GHz Caprice ECR ion source. 4 ) Typical spectra measured at 0, 30, and 90 degrees are shown in
Fig. 1. Theoretical Auger transition energies are also
indicated in Fig. 1. 2 ) The intensities of the Auger electrons from the triplet states are evidently stronger thanthose from the singlet states. All spectra measured at
0° to 180° have had this feature. Up to now, we havenot calibrated the absolute efficiency of the detector,
and therefore we can not extract the production crosssections of the doubly-excited states from our spectra.
However, at least we can mention that the intensitiesof triplet states are predominant at all observation angles. This means that in this collision system, the production of the triplet states are dominant processes
in the double-electron transfer processes. To discuss
about the mechanism to enhance the production crosssections of triplet states, we need more precise measurements.

'L-ls'2p'L -b'2s

10

15

20

25

30

35

Electron Energy reV]
Fig. 1. Ejected electron spectra from the doubly-excitedstates of N 3 +**(1i3l3lj produced by collisions of N 5 +ions with Ar atoms at three observation angles. Arrows
and solid lines indicate the theoretical Auger transition energy to the N 4 +(1s22s) and the N 4 +(1s22p), respectively. Upper-left descriptions are the singlet doubly-excited states and the triplet doubly-excited states.

References
1) Y. Kanai et al.: Nucl. Instrum. Methods Phys. Res. B
98 , 81 (1995).
2) S. Kitazawa et al.: J. Phys. B 31, 3233 (1998).
3) Y. Tamagawa et al.: RIKEN Accel. Prog. Rep. 30, 145(1997).
4) Y. Kanai et al.: RIKEN Accel. Prog. Rep. 30, 168(1997).

97

RIKEN Accel. Prog. Rep. 32 (1999)

Double Electron Capture vs. Target Excitation in
Slow He 2 + + He Collisions
B. Nystrom, Y. Nakai, T. Kambara, and Y. Kanai
Photon emission following slow ion-atom collisions
has been observed for the collision system He 2+ +2

He + + He® x -o • EEl -

+ -

Pls2p
Tls2p
Pls3p
Tls3p
Pls4p
Tls4p

10' L--_'--_'--_"--_'--~'----.J,-------'---I
o
10
20
30
40
50
60
70

Collision Energy [keV]

Fig. 1. Beam-energy dependent photon-emission intensities from the lowest singlets in neutral helium. Datafor the excited projectiles after double-electron capture
processes are plotted with encircled marks and denotedby P in the legend, whereas those for the excited target are plotted without circles and denoted by T. These
data points are intensity-calibrated in order to facilitate
direct comparison.

98

He. The energy of the incoming beam of helium
ions was varied between 18 and 36 keY. In particular, the velocity-dependent photon emission for theIs2 ISo-lsnp IP 1 (n:S; 4) resonance series in neutral
helium were measured. The measurements were donein such a way that the Doppler shift is used to separate whether the photons originated from the projectileions or the target atoms. To our knowledge, this is thefirst time that these two processes, Double-Electron
Capture (DEC) and Target Excitation (TE), are separated for this collision system using photon emission
spectroscopy. The work has been performed with the
14.5-GHz Caprice ECR ion source at RIKEN 1 ) by using a recently installed l-lLm grazing incidence VUVspectrometer. 2)
Figure 1 shows the development in the measured
photon emission intensity with the energy of the impinging beam of He 2+ ions. The intensity response forthe setup is calibrated with the help of known photon emission cross sections 3 ) for Xe 7 +, 8 + . Some morework is still needed in order to make a detailed comparison with theory, primarily to correct for possible
lifetime effects and for the finite observation window. 4 )However, there are resemblance between the measured
data and the theoretical calculations. 5)
References
1) Y . Kanai et al.: RIKEN Accel. Prog. Rep. 30, 168(1997).
2) B. Nystrom et al. : RIKEN Accel. Prog. Rep. 31, 96(1998).

3) M. Druetta et al.: Nucl. Instrum. Methods Phys. Res.
B 98, 211 (1995).
4) R. K. Janev et al.: Phys. Rep. 117, 265 (1985).
5) W. Fritsch.: J. Phys. B: At. Mol. Opt. Phys. 27 3461
(1994).

RIKEN Accel. Prog. Rep. 32 (1999)

Ion-Velocity Effects on Defect Production in an Ion-IrradiatedHigh-T c Superconductor
N. Ishikawa, Y. Chimi, N. Kuroda, A. Iwase, and T. Kambara
In the present paper, we report our recent resultson the defect production by swift heavy ions in highTc superconductors EuBa2CU30y with the emphasis on the velocity effect. Thin films of the highTc superconductor EuBa2CU30y (EBCO) were prepared on MgO substrates by an rf magnetron sputtering method. The EBCO thin films were c-axis oriented and thickness of the samples was about 0.3 /-Lm.
These samples were irradiated with the following highenergy ions at low-temperature (100 K): 120 MeV
35CI8+ , 90 MeV 58Ni6+ , 90 MeV 127 19+, and 200 MeV
197 Au 13+ produced from the tandem accelerator at
JAERl (Japan Atomic Energy Research Institute)Tokai, and 3.54 GeV 136Xe31+ and 3.84 GeV 181Ta37+
from the Ring Cyclotron at RIKEN (The Institute ofPhysical and Chemical Research). Using the above
ions we varied the values of electronic stopping power
Se from 10 to 47 MeV /(mg/cm 2 ). In-situ measurements of the fluence dependent electrical resistivity
were performed at a fixed temperature (100 K) byemploying the conventional four- probe method. It should
be noted that the sample thickness (0.3 J.Lm) is muchsmaller than the ion ranges (> 7.4 J.Lm), meaning thatthe energy loss of incident ions during their passage
through the sample is much smaller than the incident
ion-energy, and that the irradiating ions do not remainin the sample as impurities. Since the irradiations andmeasurements are performed at low temperatures, we
can rule out the possibility of thermal annealing of theirradiation-induced defects. Figure 1 shows the resistivity change (tlp/ p) as a function of the fluence of
irradiation for various high-energy ions. Low-energy( rv 1 Me V) ion irradiations were performed for EBCO
thin films previously, and we found that for the lowenergy ion irradiation the defect production is dominated by elastic interaction between irradiating ionsand target atoms. 1,2) By comparing the results between low and high energy ion irradiations, we findthat resistivity change by the high-energy ion irradiations, shown in Fig. 1, is much larger than that by the
low-energy ion irradiations. This indicates that mainly
the electronic excitation contributes to the defect production in EBCO when irradiated with high-energy(90 MeV-3.84 GeV) ions. Generally the Se which isdefined as an energy transferred from the irradiating
ion to the target electrons per unit path length hasoften been accepted as one of the parameters to characterize the defect production process. However, in
this study, the ion-velocity dependence in the defectproduction has been observed even for the same Se.
In Fig. 2, a comparison of resistivity-fluence curves
is made for two irradiations with the same Sc values(1"V28 MeV /(mg/cm 2)) but with much different velocities. A 3.54 GeV Xe ion is 6.1 times faster than a
90 MeV I ion. From this figure, we see that even forthe same Se value, irradiation effect differs for different velocities: the faster ion causes a smaller change inresistivity, thereby showing the velocity effect.

o

Q

Q

<l

~. "

4

.. ·····3.54GeVXe

8cD ( 1011 cm-2)

12Fig. 2. The value of 6.pj po plotted as a function of
ftuence for irradiations with 90 MeV I and 3.54 GeV
Xe. These two irradiations have the same Se values,
rv28 MeV j{mgjcm 2 ). A 3.54 GeV Xe ion is faster thana 90 MeV I ion.

Fig. 1. The resistivity change, 6.p, norrrialized by theresistivity before irradiation, po, plotted as a functionof ftuence <P for the EBCO irradiated with various highenergy ions.

References
1) N. Ishikawa, A. Iwase, Y. Chimi, H . Maeta, K. Tsuru,
and O. Michikami: Physica C 259, 54 (1996).
2) N. Ishikawa, Y. Chimi, A. Iwase, K. Tsuru, and O.
Michikami: J. NucL Mater. 258/263, 1924(1998).

99RIKEN Accel. Prog. Rep. 32 (1999)

Vortex Pinning of Splayed Columnar Defects in Bi2Sr2CaCu20y
N. Kuroda, N. Ishikawa, S. Okayasu, A. Iwase, H. Ikeda,* R. Yoshizaki, * and T. Kambara
A limit on technological advances of high temperature superconductors comes from the intrinsically
low critical current density J e stemming from vortex motion. Columnar defects produced by the irradiation with swift (rv 1 Ge V) heavy ions can pin
down the magnetic vortices much more effectively
than the other kinds of defects such as point defects.
Recently, in YBa2Cu307-8 (YBCO) a dispersion (orsplay) in the orientation of the columnar defects has
been found to improve the pinning efficiency strongly,
compared to a parallel set of columns,1) as predicted
theoretically. 2) We have investigated the "splayed effect" in Bi2Sr2CaCu20y (Bi-2212) single crystals toevaluate the influence of anisotropy on the splayed effect. The anisotropy of Bi-2212 with an anisotropy parameter 'Y ~ (me/mab)1/2 rv 200 is much higher thanthat of the YBCO with 'Y rv 6, where me is the effective
mass along c-axis and mab is that in ab-plane.
Bi-2212 single crystals were grown by a travelingsolvent floating zone (TSFZ) method and were irradiated with 3.8 GeV 181Ta37+ at the RIKEN Ring
Cyclotron. The three samples used' for irradiation
were cleaved and cut from one large crystal with T e of91 K. Three samples had almost the same dimensionsof 1.4 x 1.7 x 0.04 mm 3. The ion beam was tilted fromthe c-axis by ±20°, +20°, and 0° to produce splayed,
inclined, and parallel columnar defects. The pinning
properties of Bi-2212 with different configurations ofcolumnar defects were compared with one another. In
all cases, the total pin density in ab-plane of the crystal was 8 x 10 10 /cm 2 , which corresponds to a doseequivalent matching field B4> = 1.6 T. The irradiation
reduced T e by 6 K to be 85 K because of the production of damage.
We found that the splayed effect was not significant in Bi-2212 at low temperatures well below Te.
Figure 1 (a) shows the magnetic hysteresis loops at
30 K. The width of hysteresis loop ~M proportional
to the critical current J e was smaller for splayed configuration (±200) than that for parallel one (0°) at allmeasured fields. Moreover, ~M for ±20° was smaller
than that for + 20°. The difference in the critical current originates from the difference in the vortex state
among splayed, inclined, and parallel columnar defects. The vortex lines at low temperatures for splayed,
inclined, and parallel columnar defects 2,3) are illustrated in Fig. 2. The vortex lines are entangled for
splayed columnar defects. 2) If the potential barrier tovortex-line cutting U x 4) is large compared to the thermal energy, entangling vortex lines can lead a viscous
behavior with much improved transport properties.
Cryogenics Center, University of Tsukuba

100

-1. 0
-1.5~~~~~~~~~~~~~~-0. 02-0. 01

0

O. 01

O. 02

B (T)
ex

Fig. 1. Magnetic field dependence of magnetization in
Bi-2212 with splayed, inclined, and parallel columnar
defects (a) at 30 K and (b) at 77.3 K . The external
field Bex is parallel to the c-axis.

splayed defects

inclined defects

parallel defects

Fig. 2. Illustration of vortex lines for splayed, inclined,
and parallel columnar defects.

However, in Bi-2212, the anisotropy is so high that thevortex-line cutting barrier U x (ex: 1/ 'Y ) is very low. As aresult, the "splayed effect" is not significant. Furthermore, in extremely anisotropic Bi-2212, the unpinnedvortices produced by splay at the defect-defect intersections where two defects cross each other are easy
to move, stimulating vortex to creep. A large numberof intersections exist in the sample with the density of
2tan20° / d 3 rv 10 16 / cm3 , where d is the average spacing between two defects. For the inclined columnar
defects, a small part of vortex line cannot be pinned
in the columns, owing to the mismatch between themagnetic field direction and the direction of column.
This causes the pinning efficiency of the inclined defects (+20°) to reduce less than that of parallel defects(0°).
On the other hand, at 77.3 K, the splayed defects

slightly enhance the width of hysteresis loop ~M, compared with the inclined and parallel columnar defects,
as shown in Fig. 1 (b). This may be due to the enhancement of c-axis coupling of vortices, resulting from theincrease of coherence length along the c-axis near T c'
References
1) L. Krusin-Elbaum et al.: Phys. Rev. Lett. 72, 1914
(1994) .
2) T. Hwa et al.: Phys. Rev. Lett. 71, 3545 (1993).
3) G. Blatter et al.: Rev. Mod. Phys. 66, 1346 (1994).
4) C. Carraro et al.: Phys. Rev. B 51, 534 (1995).

101

RIKEN Accel. Prog. Rep. 32 (1999)

Columnar Defect-Induced Strain and Superconductivity in
Bi2Sr2CaCu20x Observed by LT-STS/STM
N. Nishida, H. Sakata, S. Kaneko, Y. Ono, and T. Kambara
Recently, uniaxial strains on high-Tc copper oxide superconductors (HTSC) have attracted muchattention, because a thin film of the epitaxiallygrown La1.9SrO.l CU04 single crystal (Tc ~ 25 K) on
LaSrAI0 4 has been reported to show 100% increase in
the superconductng transition temperature (Tc) due
to the epitaxial compression in ab-plane. 1) In HTSC
the irradiation of high energy heavy ions can generatecolumnar defects which are amorphous regions along
the ion tracks of 3- 12 nm in diameter. We have irradiated Bi2Sr2CaCu20x single crystals (Tc ~ 86 K) with
3.5 GeV 135Xe31+ ions, 3.8 GeV 181Ta37+ ions, and
3.1 GeV 209Bi 37 + ions at RIKEN Ring Cyclotron, andhave studied the generated columnar defects by a lowtemperature scanning tunneling spectroscopy and microscopy (LT-STS /STM) and by a transmission electron microscope (TEM). A columnar defect has been
observed as an insulating and amorphous region as reported before. 2) Columnar defects induce strains in thesurrounding crystalline region because the volume in
the amorphous region is locally increased. We havesucceeded in observing the strain around columnar defects and in measuring the local density of states ofquasi-particles, Ns(E, r) , by LT-STS/STM. Here we
report influence of strain on the superconductivity of
Bi2Sr2CaCu20x (x rv 8).
The samples were irradiated by heavy ions both inparallel and in perpendicular to the c-plane. Figure 1

shows the strain observed by STM on c-plane surfaceof BbSr2CaCu20x. Heavy ions were injected almostin parallel to the c-plane and in the [100] direction The
columnar defect runs about 6 nm beneath the surface.
The injection angle has been found to be 5° from theelongated shape of the columnar defects on the c-planesurface. The white region along the [100] direction in
the middle part of Fig. 1 indicates the geometrical protrusion due to the columnar defect running beneath thesurface. A superstructure can also be seen as a modulation with about 25 A cycle along the [010] direction.
We have found that the swell of the surface is abouta few tenths of nanometer high and 20 nm wide, fromthe profile shown in Fig. 2. The tensile strain in thisregion was estimated to be 10- 3- 10- 4 •

E 0.1
.s
N

a..

distance (nm)Fig. 2. The STM profile measured along the arrow line
marked in Fig. 1.
In the case of the columnar defect running perpendicular to the c-plane, on the other hand, a compressive strain of the similar magnitude as the case of thetensile strain is induced on the c-plane around it. In
both cases we have measured the differential tunneling conductances, dI/ dV , around the columnar defects
by LT-STS/STM to obtain Ns(E, r). The measured
Ns (E, r) 's have not exhibited an appreciable change
and were the same as those previously observed 3) on
the flat c-plane surface of Bi2Sr2CaCu20x' It can besaid therefore that in Bi2Sr2CaCu20x the strain in theorder of 10- 3-10- 4 does not bring about a remarkablechange in the superconductivity, whether it is tensile
or compressive.

Fig.

1.

Constant-current STM topographic image(50 nm x 50 nm) of c-plane of BbSr2CaCu20x (x r-v 8)
obtained at 4.2 K with tunneling current of 0.2 nA andbias voltage of 0.5 V. A columnar defect runs along [100]direction 6 nm beneath the surface.

102

References
1) J. -Po Locquet et al.: Nature 394, 453 (1998).
2) N. Nishida et al.: RIKEN Accel. Prog. Rep. 30, 101(1997).
3) S. Kaneko et al.: Physica C 298, 105 (1998).

RIKEN Accel. Prog. Rep. 32 (1999)

Magnetic Excitations from the Two-Leg Spin Ladderin La6Ca8Cu24041
M. Matsuda, K. Katsumata, and R. S. Eccleston*One- and two-dimensional antiferromagnets show
novel phenomena originating from quantum fluctuations. A spin ladder system is important to study
a crossover from one- to two-dimensions. Extensive
studies have been performed on the spin ladder systemboth theoretically and experimentally. 1) An interesting
property is that the ladders with even-numbers of legs
have an excitation gap but those with odd-numbersof legs show gapless excitations. It is also predictedthat superconductivity occurs if the ladders with evennumbers of legs are doped with carriers.
We report on the magnetic excitations from S = ~two-leg ladder (Fig. 1) in L8{)CasCu24041 single crystals.
Hr·}·······
....

-

1+

....

,,

It or

....

....
..,

....

It
It
It

t~
,

>t~
,,
(>t~

cL

,,

t~

a

• Cu
0

0

,

>t~

,,

..,

....

~

,,

(t~
"..,

,

I~ .. -..........

Figure 2 shows a summary of the inelastic neutron
experiments on L8{)CasCu24041 measured at 20 K.
The broken curves are scan loci. The closed circles andthe solid straight lines between them represent the positions where peaks are observed in neutron inelastic
spectra. Magnetic excitations from the two-leg ladderexist between ",35 and ",200 meV. The solid curves
are guides to the eye.

::

,

t~

The neutron scattering experiments were carried out
on the High Energy Chopper Spectrometer (HET) on
the ISIS Pulsed Neutron Source at the Rutherford Appleton Laboratory. The experiments were carried out
with incident neutron energies of 150, 300 , 500, 600,
and 800 me V which are monochromated by a rotating
Fermi chopper which is phased to the source.

Fig. 2. w - Q dispersion relation in La.t>Ca8Cu 24 041 measured at T = 20 K.

We are now completing the measurement of full dispersion curve for the S = ~ two-leg l(l.dders. The experimental curve will then be fitted with a theoretical calculation from which one can determine the exchange interactions between copper spins parallel andperpendicular to the ladder. It is also interesting to see
the effect of the holes on the excitation spectrum bycomparing the results of La6CaSCu24041 with those of
Sr14CU240 41,2)
References
1) E. Dagotto and T. M. Rice: Science 271 , 618 (1996).
2) R. S. Eccleston, M. Uehara, J. Akimitsu, H. Eisaki, N.
Motoyama, and S. Uchida: Phys. Rev. Lett. 81, 1702(1998) .

Rutherford Appleton Laboratory, UK

103

RIKEN Accel. Prog. Rep. 32 (1999)

Laser Spectroscopic Study of Metastable Ne Atoms
in Gaseous and Liquid He
Q. Hui, E. B. Gorden, M. Nakamura, and M. Takami
We are currently preparing a CW-Iaser system forstudying the laser induced fluorescence (LIF) spectrum from the singlely-charged atomic ions with one
unpaired valence electron, i.e. alkaline earth ions. In
the meantime, using a similar experimental setup andpulsed lasers, we are also trying to measure the LIF
spectrum of metastable Ne atoms in the gaseous andliquid helium. It is well known that valence electrontransitions of neutral atoms in liquid He show a large
line-shift and broadening. This is resulted from theinteraction between the valence electrons of neutral
atoms and the surrounding helium atoms. A so-called"bubble model" has been successfully applied to interpret the observed line-shifts and broadening. I) Recently experiments by our group and by other groups
have revealed non-radiative relaxation in the Ag andalkali atoms excited to a p-state. 2 ) This observation
has been explained as a result of a metal-helium exciplex formation. 3) Metastable Ne atom is similar to
the alkali atoms and alkaline earth ions in its electronic structure, and is expected to show a similar
dynamics in liquid helium as those observed with alkali atoms and Ag. A preliminary experiment withthe metastable Ne atoms dispersed in liquid helium
showed almost identical line position and width as ingas phase. 4 ) Present work is also aimed to clarify thismystery.
The experiments were carried out in a similar cryostat as reported in the last issue of this Progress
Report. 5) Instead of a laser-sputtering ion source, agas-phase discharge in a glass capillary at above liquid
helium was used to produce metastable Ne atoms, Ne*.
The Ne* atoms were transported into superfluid heliumin a glass cell hanging above the bulk liquid helium by
a He gas jet through an orifice. A pulsed dye laser
was used to excite the Ne atoms from the long-lived
2p5(2P 3 / 2 0)3s[3/2bo metastable state. Laser induced
fluorescence (LIF) was collected at a right angle by aphotomultiplier via a monochromator (Fig. 1).
As the first step of the experiments, we have observed the LIF from metastable N e atoms in the He gas
jet 1-2 cm below the orifice. Excitation spectrum of
the 2p5(2P3 / 2 °)3p[3/2bo f- 2p5(2P 3 / 2 0)3s[3/2ho line
(614 .3 nm in free spac), recorded by scanning thedye laser wavelength and monitoring the emission
at 692.9 nm, shows a nearly symmetric profile with.-vI cm- I line-width (FWHM). We were unable to observe the emission spectrum on the same line becauseof the strong scattering of laser. Emission spectrumof the 692.9 nm line, which has the same upper stateas the 614.3 nm line, shows an asymmetric shape with104

discharge

Helltransfer
tube

monochromator

cell

He II

dye laser

Fig. 1. Experimental setup.

a steep rising edge on the short-wavelength side anda smoother falling edge on the long-wavelength side
(Fig. 2). The emission line-width is .-v6 cm- I , which ismuch wider than the excitation line. The asymmetricprofile and large broadening of the emission line havenot been reported before.
In the upper state of the 692.9 nm line , an unpaireds-electron in the lower state is excited to a p-orbital.
According to the theoretical model proposed to explain
the LIF spectra of the alkali and Ag atoms in liquid

692

693

694

695

Wavelength (run)Fig. 2. Emission spectrum of Ne atoms in cold He jet.

helium and cold gas helium,3) a number of helium
atoms are attracted by the charged ion-core of the Ne*
atom to the nodal plane of p-orbital where the electron
distribution is zero, thereby forming a Ne*He n exciplex. This will reduce the total energy of the system
and will result in a red-shift and line-broadening.
We have also observed a narrow excitation line whenthe excitation laser beam was moved into superfluid
helium as in Ref. 4. However, it cannot be excluded
that the signal was actually from Ne* atoms in gas
phase, which may be excited by scattered laser light.

We plan to improve the setup to reduce this scatteringand repeat the experiment.
References
1) A. P. Hickman and N. F. Lane: Phys. Rev. Lett. 26,
1216 (1971).
2) J. L. Persson et al.: Phys. Rev. Lett. 76, 1501 (1996).
3) Z. J. Jakubek et al.: Phys. Rev. Lett. 79, 629 (1997).
4) E. B. Gordon: unpublished material.
5) Q. Hui and M. Takami: RIKEN Aceel. Prog. Rep. 31,
104 (1998).

105

RIKEN Accel. Prog. Rep. 32 (1999)

Channeling Analysis of ZnSeTe t
T. Maruyama, T. Hasegawa,* N. Komuro,* H. Yamada,* W. Ohtsuka,*
K. Akimoto, K. Maeda, and E. Yagi
ZnSeTe is an important material in application to
the blue-green laser diodes. However, it is difficult tocontrol the electronic properties in the n-type ZnSeTeeven at low content of Te, while ZnSe is generally of
the n-type. Our previous extended X-ray absorption
fine structure (EXAFS) study suggests that some kindof acceptors not related to CI atoms are formed in the
Cl-doped ZnSeTe layer and that they compensate its
n-type conductivity expected to be induced by the CIdoping.1) In order to clarify this compensation mechanism, we have carried out Rutherford backscattering
spectrometry lion channeling (RBS/C) and particle induced X-ray emission/ channeling (PIXE/C) measurements for undoped ZnSeTe.
The undoped ZnSeTe thin films were grown on GaAs
(100) substrate by means of molecular beam epitaxy.
The content of Te atoms in the sample was 27%. Typical thickness of the samples was about 1.5 j.Lm.
The lattice location of the constituent atoms of the
ZnSeTe layer was investigated by RBS/C and PIXE/C
using a 2 MeV He+ beam provided from a small tandem accelerator. The backscattering angle was 150 0
and the characteristic X-rays were collected by a Si
(Li) detector placed at an angle of 135 0 with respect
to the incident beam.
Figure 1 shows the channeling angular profiles of the
Se Ka. and Te La. X-rays in ZnSeTe across the <100>and <110> axes obtained by the PIXE/C measurements. The intensities of X-ray from the Se and Te
atoms give rise to channeling dips in both directions.
For both <100> and <110> channels, the angular profiles are much shallower than those in ZnSe and ZnTe.
This deterioration reflects the structural inhomogeneity induced by the local distortion in the ternary compounds. Further, the Se and Te X-rays exhibit almost
same channeling dips for the < 100> channel, whereas
the Te-dip is shallower than the Se-dip for the < 110>channel, although their angular half-widths are approximately same. These results indicate that for the<100> channel the Te atoms are shadowed by the Se
atomic rows, whereas for the <110> channel most ofthem are shadowed by the Se atomic rows, but some
portion of them are displaced from the Se atomic rows.
The sites which are shadowed by the <100> atomic
rows, but not shadowed by the < 110> atomic rows,
are tetrahedral (T) interstitial sites. Therefore , it canbe said that most of the Te atoms replace the Se atoms
and the rest are located at T sites. Previous ab initio
Condensed from the article in Proc. 2nd Int. Symp. on Blue
Laser and Light Emitting Diodes (2nd ISBLLED).
On leave from Insti t ute of Materials Science, University ofTsukuba

106

0.8
"0
Q)

A

1<100>1

a

(a)

~

6
D

>= 0.7 -

6
D

"C

~

Q.)

.~

6

(ij

D

E 0.6 ~

A
6
D

0

Z

6

~

D

6
D~

0.5

o Se

6

I

I

I

I

I

I

I

-0.8 -0.4 0.0 0.4 0.8
Tilt Angle (deg)
0.8

D

-

1<110>1

6

6

(b)
D

"C

Q)

>= 0.7 -

D
6
6

D

D

"C
Q)

6

.~

(ij

6

r/'6

E 0.6 -

10..

D
66

D~

0

Z

aD~
.. D

0.5

I

I

I .

a~
~ Te
o Se

I

I

I

-0.8 -0.4 0.0 0.4 0.8
Tilt Angle (deg)Fig. 1. PIXE angular scans of Se K a and Te L a for
ZnSeTe across the (a) <100> and (b) <110 > axes.

pseudo-atomic-orbital calculation on native defects in
ZnTe showed that Te atoms at T sites act as acceptors
in an n-type conductivity, whether Te atoms are surrounded by Zn atoms or by Te atoms. 2 ) Therefore , itis considered that Te atoms at T sites act as acceptors
in ZnSeTe and compensate its n-type conductivity.
From the PIXE/C and RBS/C results, it was foundthat some portion of Te atoms are located at T sites
in ZnSeTe ternary compounds. This intrinsic defectis a strong candidate of the compensation center in
ZnSeTe.
References
1) K. Akimoto et al.: Nonlinear Optics 18, 235 (1997).
2) R. W. Jansen and O. F. Sankey: Phys. Rev. B 39, 3192
(1989).

RIKEN Accel. Prog. Rep. 32 (1999)

Single Event Burnout in Power MOSFET Causedby High-Energy Ions
S. Matsuda, S. Kuboyama, T. Suzuki T. Hirose, H. Ohira, T. Kohno, and M. Kase
Semiconductor devices to be used for artificial satellites and spacecrafts are affected by the radiation in
space. It is well known that the incidence of high energy heavy ions into semiconductor devices causes several kinds of anomalies called single event phenomena(SEP): i.e., single event upset (SEU) on memory device, single event latch up (SEL) on CMOS and LSI
etc., and single event burnout (SEB) caused by theheavy ion passing through the active area of PowerMOSFET. National Space Development Agency ofJapan (NASDA) has studied SEB in Power MOSFET
with heavy ions from the RIKEN Ring Cyclotron. I)
Power MOSFET's of 200 V class have been developed to be used for the future artificial satellites.
To determine the design parameters of the PowerMOSFET, we have performed irradiation tests on
several types of samples with a beam of Ni 25 + at
25 MeV /u (total energy of 1450 MeV), and studied
the breakdown voltage data concerning with SEB. Because the Ni ion beam passes through the atmosphere,
the energy of ion beam on the samples was approximately 286 MeV. Therefore, the linear energy transfer(LET) of the ions in the sample surface(Si) was about
26.7 MeV /(mg/cm2 ), and the range was about 44.7 /-Lmin Si.
From our previous study, it is known that SEB tolerance of Power MOSFET depends on the Drain-Source
Breakdown Voltage (BVDs) and the cell geometry. But
it was not enough to fix all the design parameters.
Therefore, several types of samples which were fabricated with various parameters for space applications
were prepared. The irradiation test results are shownin Figs. 1 and 2. Figures 1 and 2 show the p-pitch (distance between the two p-Iayers in Power MOSFET)
dependence and n+ layer As-doping density (in the n+layer in Power MOSFET) dependence on SEB threshold, respectively. Cell geometry of all the samples wasa stripe cell, because the stripe cell had better SEB tolerance than the square one according to our previous
irradiation tests.
Effect of the p-pitch size on the SEB tolerance wasstudied first. In general, when p-pitch is smaller, theSEB tolerance increases; but the Ron (a resistancevalue when the transistor is "ON" state) characteristic is degraded, in contrast. Therefore, p-pitch size
was reduced from 9 /-Lm for our samples. As shownin Fig. 1, as p-pitch was reduced, SEB threshold increased until 6 /-Lm; but SEB threshold decreased at
3 /-Lm of p-pitch size. Therefore it seems that there isan optimum p-pitch size in Power MOSFET.
Effect of the n+ layer As-doping density was studied

280
260
240
....., 220
G
200
(I)
Cl 180
160

0
0

iii

•

I

>

140
120
100

03.50E+15
2

3

4

5

6

.4.00E+15
7p-pitch [J.l m]

8

9

10

Fig. 1. The p-pitch dependence on SEB threshold.

300
280
,--,

260

G240

•

~ 220

> 200

•
•

•

•

180
160 '---_ _........_ _---''--_ _-'--_ _---1
2:.5E+15

3.0E+15

3.5E+15

4.0E+15

4.5E+15

As-doping density [atm/cm2J

Fig. 2. The n+ layer As-doping density dependence on
SEB threshold.

next. From the previous study, the SEB mechanismof Power MOSFET is known that the parasitic bipolar junction transistor (BJT), inherent to the doublediffused MOS (DMOS) structure, is turned on by incidence of high-energy ions. 2 ) It is thus expected thatthe decrease of current gain (hFE) of the parasitic BJT
can increase SEB tolerance. To decrease hFE of parasitic BJT, the As-doping density in the n + layer was
decreased. As shown in Fig. 2, SEB threshold was increased as As-doping density was decreased. But, decrease of the As-doping density degrades the electricalcharacteristics such as Ron. It is necessary to consider
this point.
Considering the several irradiation test results andthe electrical characteristics, we found the optimum
design parameters, and developed two types of PowerMOSFET (2SK3041, 2SK3146) for space applications.
2SK3041 will be used for the artificial satellite named
ETS-VIII, which will be launched in 2002.
References
1) S. Kuboyama et al.: IEEE Trans. Nucl. Sci. NS-39,
1698 (1992).
2) M. Allenspach et al.: IEEE Trans. Nucl. Sci. NS-43,
2927 (1996).

107

RIKEN Accel. Prog. Rep. 32 (1999)

Possibility of the "~ Effect" in the Zn-Substituted
Bi-2212 System Studied by p,SR
1. Watanabe, M. Akoshima,* Y. Koike,* and K. Nagamine"keffect", meaning that
Existence of the so-called
the high-Tc superconductivity (SC) is anomalously
per Cu-atom,
suppressed at the hole density of p =has been established in the La2-xBaxCu04 system. 1- S )A magnetically ordered state was confirmed by previous muon spin relaxation (j.LSR) studies when the SC
was suppressed. 4,S) Subsequently, a stripe structure ofa spin density wave state and a charge density wave
state was suggested from a neutron scattering study.6)
Relationship between the magnetically ordered state
and the suppression of the SC has been discussed.
Recently, Akoshima et al. suggested from transport
studies a possibility of the existence of theeffect"in the Zn-substituted Bi-2212 system,
Bi2Sr2Cal-x Yx(Cul-yZnyhOs+8.7) They found similar anomalous suppression of the SC in the Znsubstituted samples at p rv
They suggested thatthe substituted Zn played as a pinning center to makea charge and/or a spin ordered state. We applied j.LSR
measurements to investigate magnetic properties of theZn-substituted Bi-2212 samples. Preparation procedures of sintered samples are written elsewhere. 7) The
j.LSR measurements in the zero-field (ZF) were carriedout at the RIKEN/RAL Muon Facility in the UK. A
pulsed positive surface muon beam was used. Measured temperature range was from 0.3 to 300 K.
Figure 1 shows the ZF-j.LSR time spectra of the Znsubstituted sample with x = 0.3125 and y = 0.025
at 0.30, 1.74 and 19.2 K. The preliminary analysis
showed that the depolarization behavior deviates fromthe Gaussian-type to the exponential-type below 10 K,

k

"k

k.

indicating the appearance of an effect of dynamicallyfluctuating internal fields at a muon site. S)
Figure 2 shows the temperature dependence of the
exponential component of the depolarization rate. Enhancement of the depolarization rate was observed below about 10 K in the Zn-substituted sample at p rv
where the SC is anomalously suppressed. The enhancement of the depolarization rate can be regarded as that
the Cu spins show the slowing down behavior which is
caused by the enhancement of the magnetic correlation
between the spins. No enhancement of the depolarization rate was observed in the non-Zn-substituted samples and the Zn-substituted samples with p far from
As a result, the present j.LSR study revealed that bothof p being and the Zn-substitution are essential forthe suppression of the high- Tc SC and the enahancement of the magnetic correlation. This relationshipis similar to that estabilshed in the La-systems. 1- S )Therefore, it can be concluded that the existence oftheeffect" in the Bi-2212 is likely.

k

k.

k

"k

----.
U

d)

<:Il

0.3
0.25

~

0:::
c:
0

0.2

0

0.15
0

~

N

0.1

0-

0.05

f1)

0.0
0.1

~

CI)

<
'"CI
~

0

8 B
10

100

0.5
1.74

References

§
o

Z
5

10

Time (J-lsec)
Fig. 1. ZF-j.LSR time spectra of the Zn-substituted sample
with x = 0.3125 and y = 0.025 at which the high-Tc SC
is anomalously suppressed.
Graduate School of Engineering, Tohoku University

108

0

0

Fig. 2. Temperature dependence of the muon spin depolarization rate of the exponential component of the Znand non-Zn-substituted samples.

;>.

.....~

0Temperature (K)BizSrZCal_x YiCu, -,zo,hOS+<I=<>.3125, y=O.025

1.0

0

'.;:j

·c
ell
'0

0: =0.3125. )'=0.025

0: =0.3125. )'=0.0
0: =0.20. y=O.025" : =0.20. )'=0.0

3

Cl

g

BilSrlCa,., Y.(Cu, .yZnyhOS+61) A. R. Moodenbaugh et al.: Phys. Rev. B 38, 4596
(1988).
2) K. Kumagai et al.: J. Mag. Mag. Mater. 16/11, 601(1988).
3) K. Kumagai et al.: Physica C 235/240, 1715 (1994).
4) 1. Watanabe et al.: J. Phys. Soc. Jpn. 61,3058 (1992).
5) 1. Watanabe et al.: Hyperfine Interact. 86, 603 (1994).
6) J. M. Tranquada et al.: Nature (London) 315, 561(1995).
7) M. Akoshima et al.: Phys. Rev. B 51, 7491 (1998).
8) 1. Watanabe et al.: Physica B (1999), in press.

RIKEN Accel. Prog. Rep. 32 (1999)

Muon Spin Resonance in (Ndl-ySmy)O.5SrO.5Mn03
W. Higemoto, K. Nishiyama, I. Watanabe, K. Nagamine,
A. Asamitsu,* H. Kuwahara, * and Y. Tokura*
Recent systematic studies on the perovskite typemanganese oxide (Ndl_ySmy)o.sSro.sMn031 ,2) haverevealed a competitive n at ure existing between the ferromagnetic double-exchange interaction and the antiferromagnetic charge ordering instability, which gives
rise to a temperature, magnetic field , and pressure induced transition from the ferromagnetic metal (FM)to antiferromagnetic insulator (AFI). This transition isaccompanied with a change of the resistence by several
orders of magnitude, and the phenomenon is known as
the colossal magneto resistence (CMR). The competition between the FM state and AFI state is rather
sensitive to the Mn-O-Mn bond angle or Sm ratio, y.
In particular, a metastable FM phase appears in the
0.85 < y < 1 region below 100 K . It was suggested
that the suppression of ferromagnetic double-exchangeinteraction by a competing antiferromagnetic chargeordering instability occur also in paramagnetic phasefrom the magnetic scesepitibility measurements 2,3) andmuon spin relaxation measurements(J1+SR).4) Paramagnetic shift measurement is very useful to know thehyperfine coupling constant. To investigate the detailof the magnetic state in the paramagnetic phase , wehave applied the RF muon spin resonance technique(RF-J1+SR).
RF -J1+SR experiments were carried out at Port-2 of
RIKEN-RAL Muon Facility. Multidomain crystals of(Ndl-ySmyh-xSrxMn03 (x ,. . ., 0.48, y ,....., 0.875) weregrown by travelling floating zone method and were cut
to disk shape.
We have clearly observed the resonance curve under
the RF field of 47.0000 MHz as shown in Fig. 1. The
local magnetic field BJ-L at J1+ sites can be expressed,
in general, as

47r
Bp. = HhJ + Hdip + (3 - N)M + Ho·(1)

Here, HhJ is the hyperfine field, Hdip the dipolar field
due to the surrounding magnetic atoms inside theLorentz cavity, N the demagnetization coefficient, M
the host magnetization, and Ho the external field. We
define the shift K as

K = HhJ = B/-L - Ho .
Ho
Ho

(2)

Here, we have neglected the term corresponding to
the dipolar field because of the symmetry of the crystal. Figure 2 shows the preliminary results of K-X
plot. Surprisingly, the slope of the K-X plot suddenly
changes at ",,200 K. This result suggests that the hyperfine coupling constant AhJ changes at ,.....,200 K.
JRCAT

0.200
0 .1800.120
0. 1000.165~Q) 0.160

Y(a)Graphite

E
E
0.155
>.

I/')

<t: 0 .150
'0

Q)
«i
0.145

~ 0.140

£

(b)

290K
3400

3500

3600

0.1 400.1315

0.136

0.134
0.132

(c)

150K

0.130 '---_--'-_----'~_-'-_
3300
3400
3500
3600

____'o---.J

3700

Field{G)Fig. 1. RF-p,SR spectrum in (a) Graphite as a reference and (b, c) in (Ndo.125Smo.875)o.52Sr0.48 under the
RF-field.

Paramagnetic Phase
290k·,~
-0.50

..

,

. , ,.

-1.00

142K~

-1.S0 L......o-....................L~...................J..~..............'-'-'-~
o 0 .02 0.04 0.06 0.08 0.1 0.12 0.14

X(emu/mol)

Fig. 2. K-x plot in the paramagnetic phase.
However , such anomalies at ,.....,200 K are not observedin the other experiments. Possible states are underconsideration.
References
1) Y. Tokura et al.: Phys . Rev. Lett. 76 , 3184 (1996).
2) H. Kuwahara et al.: Phys. Rev. B 56, 9386 (1997) .
3) H. Kuwahara et al.: Science 272, 80 (1996).
4) W. Higemoto et al.: Physica B, in press; RIKEN Accel.
Prog. Rep. 31 106 (1998).
109

RIKEN Accel. Prog. Rep. 32 (1999)

Level Crossing Resonance in 2H-NhSe2
W. Higemoto, K. Nagamine, S. Kuroda, and K. Takita
The compound 2H-NbSe2 is a 2H type transition
metal dichalcogenide. As shown in Fig. 1, 2H-NbSe2
possesses a layered structure with the layers weakly
coupled by Van der Waals' forces. Since two dimensionality dominates the system, a weak incommensurate state of the charge-density-wave (CDW) appears
below T CDW rv 32 K. Superconductivity (SC) coexists with the CDW state below Tsc "-' 7 K.l) It is
well known that the behavior of positive muons (f.L+)strongly depends on the conduction electron characterin some cases: for example, the muon quantum diffusion phenomena depend critically on the nature of the
Fermi surface. 2) We are investigating the relation between the muon behavior and the CDW and the SC
states in 2H-NbSe2 at RIKEN-RAL muon facility. In
addition, transition metal dichalcogenides are known
to be able to intercalate molecules or atoms into theinterlayer. In 2H-NbSe2' the muon is expected to behave as a hydrogen-like intercalant, and its behavior
is also interesting from an intercalation chemistry perspective.

93Nb nuclei has spin J = ~ and quadrupole moment
Q = 0.16 x 10-24 cm 2. The quadrupole frequency, w Q ,is represented by
3e 2 qQ

Q _

hw

(1)

- 4J(2J - 1)

The level crossing resonance occurs when quadrupolar splitting energy at 93Nb site matches with a corresponding Zeeman splitting energy of muon. Although,electric field gradient (EFG) at 93Nb site is known fromthe NMR experiment (e 2 qQ/h = 61.98 ± 0.2 MHz at
77 K) ,4) that of our system was not known because the
EFG at 93Nb nucleus site is produced also by muon itself. This contribution is important for determining
the muon site in LCR measurement.
Figure 2 shows the dependence of applied longitu-

0.29

290K

0.285
0.28
0.275
0.27

I

~

I

l

0.265

OSe

0.26

I

0.255
0.29

>.

Fig. 1. Crystal structure of 2H-NbSe2.

b(l) 0.285
E 0.28E~ 0.275

In this article , we report the results of muon levelcrossing resonance experiment (f.L-LCR) in 2H-NbSe2.
As we previously reported,3) microscopic state of thepositive muon in 2H-NbSe2 has been studied using
the muon spin relaxation method (f.L+SR). We foundthat the f.L+SR spectra consist of two components.
The ratio of the two components and the dynamics
of the muon change both at 140 K , at the chargedensity-wave transition temperature (32 K) , and again
at the superconducting transition temperature (7 K).
These facts clearly show that the muon states are affected by the CDW state as well as the SC state.
At T C DW , an energy gap appears in the Fermi surface and the density of states (DOS) decreases. It
is known that hopping motions of muons in a metal
are related to the conduction electrons near the Fermi
surface through the electron-drag effect. The hopping
rate increases in the SC phase. 2) However, clear explanation of our observation does not exist yet. To know
the muon position and the local state of 2H-NbSe2' wehave applied level crossing resonance (LCR) method.
110

<t:
"0

0.27

II

(l)

~ 0 .265
~

0>

(l)

......

0 .26.E 0 .255
0.29
0.285
0.28
0.275
0.27

II
I

0.265
0.26
0.255
0.25
0

100

200

300

400

500

600

Magnetic Field (G)Fig. 2. Longitudinal magnetic field dependence of themuon spin polarization. Six peaks, which are indicating
the level crossing resonance , are observable.

dinal field on the integrated asymmetry, (NF NB)/(NF + NB), which corresponds to the muon spinpolarization. Here, N F and N B are the total numberof emitted positrons counted at forward counters andbackward counters, respectively. We can clearly see thesix resonance peaks. We found that the amplitudes
of LCR peaks are reduced below 30 K. This featureclearly shows the effects of the state of charge-densitywave. To know the details of the muon position andof the local state of 2H-NbSe2' theoretical calculationis going on.
In general, microscopic muon state is very important
for the j.L+SR studies of matter. We consider that our

re~ult can be regarded as a new feature of the muon

behavior which will strongly reflect the electric state
like CDW state in particular, and will contribute to
the understanding of the microscopic muon state inmatter.
References
1) R. Sooryakumar and M. V. Klein: Phys. Rev. Lett. 45,
660 (1980).
2) For example, R. Kadono et al.: Phys. Rev. B 39, 23(1989).
3) W. Higemoto et al.:Hyperfine Interact., in press;
RIKEN Accel. Prog. Rep. 31, 110 (1998).
4) H. Ehrenfreund et al.: J . App. Phys. 42, 1491 (1971).

111

RIKEN Accel. Prog. Rep. 32 (1999)

Muon Spin Resonance in KCuCl 3 and TICuCl3
W. Higemoto, H. Tanaka, I. Watanabe, and K. Nagamine
Recently, a low dimensional magnetic system which
possesses the spin singlet ground state has been attracting a great deal of attention. From recent studies
by Tanaka et al., it was suggested that the ground stateof KCuCl3 and TICuCl 3 are spin singlet state with afinite spin gap. I) Figure 1 illustrates the exchange interactions. These systems can be described as S = 1/2
Heisenberg spin ladder systems with additional interactions. In these systems, because of the spin singlet
ground state, non-magnetic state is expected to arize
at low temperatures. If the system is non-magnetic
state, no muon spin relaxation is expected to occur.
However, as we previously reported,2) muon spin isstrongly depolarized in both systems. The origin of
the local field at muon site is still unclear. One possible origin is due to the contribution of the impurities
or chain ends. In KCuCI 3 , amount of such impurities
or chain ends is too small to induce the large magnetic
field to the whole system observed by muon. Thus, it
is unlikely that this relaxation phenomena arose fromthe impurities. One of the other possibility of the origin of the local field is due to the formation of an exotic muon state. Muon spin resonance technique isa strong tool for the investigation of the muon state.
In particular, time dependence of the muon state canbe investigated. We therefore applied this method on
KCuCl3 and TICuCh to know the time dependenceof the muon state at RIKEN-RAL muon facility. In
TICuCI3 , we have observed the muon spin relaxation
which has spectra quite similar shape as the other puresystem but of somewhat different from KCuCI 3 . So,
muon spin resonance experiments for these two materials give us much variety of the information about themuon state and magnetism in the spin singlet system.
A reference spectrum is shown in Fig. 2(a). Figure 2(b)shows the RF-J.L+SR spectra in KCuCh at various temperatures under the RF-field of 47.0000 MHz. We define "integrated asymmetry" as (NF - N B) / (NF + N B)'
Here N F and N B are total number of emitted positrons. .• .• .,~I"
I I ' .'.
\.,'
I

~

~

•••• J2
...
•

A

P

I,'.
1"3'.
I "....'.
I"
I
'.
I
'.
I
'. I
I
... I
~

a- axisFig. 1. Spin configuration of the double chain and theinteractions 1t , hand h.
112

1.10

Graphite
1.00

~

Q.i

E
E
>.

'"
""0

0.90
0.80

c(
Q)

0.70

~

CI
Q)

0.60

E
0.50
0.40

~

1.00

E
E

0.90

Q.i

>.

'"

c(

""0

.l!!

0.80

~

CI
Q)

E 0.70(b)
0.60

TICuCI 3
~

1.00

Q.i

E
E
>.

0.80

'"
""0
c(
Q)

iii

0.60

C,
Q)

E

0.40

(c)
0.20
3460

3480

3500

3520

3540

3560

Field(G)Fig. 2. Muon spin resonance spectra in (a)graphite (reference data), (b)KCuCb, and (c)TICuCb.
counted at forward counters and backward counters,
respectively. Above 5 K, we observed the muon spinresonance with a very small paramagnetic shift under
the DC-longitudinal field of 3.5 kG which was applied
parallel to the initial muon spin direction. However,
we could not observe the muon spin resonance below
5 K. This indicates that muon state or magnetic statearound muon site is different above and below 5 K.
This fact is consistent with the muon spin relaxation
results.
In TICuCI3 , the muon spin resonance was observed
even in a lower temperature (Fig. 2 (c)). We consider
that the muon spin relaxation mechanism in TICuCl 3
is different from the case of KCuCl3 at low temperatures.
References
1) H. Tanaka et al.: J . Phys. Soc. Jpn. 65, 1945 (1996).
2) W. Higemoto et al.: Phys. Lett. A 243, 80 (1998);
RIKEN Accel. Prog. Rep. 31, 105 (1998).

RIKEN Accel. Prog. Rep . 32 (1999)

JL+SR Investigation of the Magnetic Orderingin Ce3Pd2oGe6
V. V. Krishnamurthy, I. Watanabe, K. Nagamine, J. Kitagawa,*1
M. Ishikawa,*1 and T. Komatsubara*2
The Kondo-lattice compound Ce3Pd2oGe6 exhibits
heavy-fermion behaviour characterized by a huge linear specific heat coefficient CIT '" 8J I (Ce mol K2)
below 1 K and crystal field split ground state of Ceions. 1) This compound forms in a cubic phase with
Cr23C6 type superstructure, in which Ce atoms occupy two crystallographic ally inequivalent sites. The
crystal structure consists of a simple cube formed by
8 Ce(2) atoms embedded in a FCC type cubic arrangement of Ce(l) atoms. Magnetic susceptibility Xac(T)of Ce3Pd2oGe6 follows a Curie-Weiss law for temperatures above 50 K with an effective moment f..Leff =2.45 PBICe and exhibits a sharp cusp at 0.7 K.1) Electrical resistivity p(T) exhibits a minimum near 10 K,
a broad peak around 2 K characterising Kondo lattice
behaviour and an inflection point at 0.7 K. The specific heat C(T) demonstrates two anomalies, a sharp
peak at 0.7 K and a broad peak at 1.2 K. The anomaly
found at 0.7 K in X(T), p(T) and specific heat measurements has been suggested as long range antiferromagnetic (AFM) ordering. By considering the huge valueof magnetic entropy Smag C-vR In4 at 10 K), the 1.2 K
anomaly has been interpreted as quadrupolar ordering
due to a crystal field split rs quartet ground state of
Ce3+ (J = 5/2) ions. Since there isn't any suitable
nuclear probe of Ce for a microscopic investigation of
Ce3Pd2oGe6 single crystal, we have applied p+SR togain knowledge on the magnetic structure of Ce ions in
the antiferromagnetic state. Further, if the transition .
at 1.2 K is a pure quadrupolar ordering, then there
should be no anomaly in the local magnetic properties
measured by p + SR.
Ce3Pd2oGe6 single crystal was prepared in a triarc
furnace. An 8 mm diameter and 1 mm thick disc of
the crystal, with its plane perpendicular to the [110]direction was glued to a 25 pm thick silver plate andwas cooled in a 3He cryostat. p+SR measurements
were performed in zero-field, transverse field and longitudinal field conditions in the ARGUS spectrometer following the implantation of p+ pulsed beam of
momentum 27 MeV Ic at RIKEN-RAL muon facility.
Figure 1 displays few examples of zero-field spectra
measured in the paramagnetic and antiferromagnetic
regions. The spectra above 0.7 K could be fitted by an
exponential relaxation function with a nearly temperature independent relaxation rate of 0.03 pS-l. The
spectra below 0.7 K, clearly shows coherent and spontaneous precession of muons and could be reasonably
fitted byGz(t) = Aoexp( -tIT1 ) + Aexp( -At)COS(wt + ¢),*1*2

Institute for Solid State Physics, University of Tokyo
Tohoku University

where Ao is the asymmetry of the only-relaxing component and A is the amplitude of the precessing component. 11T1 is the muon spin-lattice relaxation rate.
lip. = W 127r is the muon spin precession frequency which
gives a measure of the strength of the local magnetic
field present at the muon site. A is the line width and¢ is the phase angle. The temperature dependence of
11T1 and 1/11- are displayed in Fig. 2. 11Tl does notexhibit an anomaly at TN = 0.7 K and at TQ = 1.2 K.
While the lack of an anamoly in 11T1 at TQ indicatesthat the changes in the electronic structure around Ce
due to quadrupolar ordering are minimal, the reason
for the absence of an anomaly at 0.7 K is not clear.
The discontinuous drop of lip. at 0.7 K seem to suggest
a first order antiferromagnetic transition. The coherent precession of muons below TN implies a collinear
antiferromagnetic structure.

I:::f: ,=' :.:: -::g:::r;w:~; ;.~
·

0

1

2

3
T ime

4

5

(..sl

Fig. 1. J,.L+SR time spectra in Ce3Pd2oGe6 measured forthe initial muon polarization vector P J.L (0) parallel to[llOJ direction of the crystal.

N

10

::r:
~

v\

•

~

~

.

.. , .

Ce 3Pd 20Gee.

~

PIl(O) II [1101

rQ

TN

.l!!
~

c:

~

~
a;

1fT,

0.1

\

a: 0.03

A

:

AA~~

0.01 0.2 0.3 0.4 0.5 0.6 0.7

A

A

.A

o.e 0.9 1.0 1.1

1.2 1.3

A

Temperature (I<)

Fig. 2. Temperature dependence of 11Tl and VJ.L in
Ce3Pd2oGe6 single crystal.

References
1) J. Kitagawa et al.: Phys. R ev. B 53 , 5101 (1996).

113

RIKEN Accel. Prog. Rep . 32 (1999)

Muon Spin RF-Resonance of Haldane Gap Systems
A. Fukaya, I. Watanebe, M. Hagiwara, and K. N agamine
Low-dimensional quantum spin systems with antiferromagnetic interactions, e.g. Spin-Peierls andHaldane-gap systems, have attracted much attention.
It has been clarified that the ground states of thesesystems are non-magnetic. However, enhancement of
the muon spin relaxation was commonly observed ata low temperature. 1-4) The origin of this enhancement
has not been clarified yet.
In order to resolve this problem, it is important toexamine the local field at the muon site. We have measured the muon spin resonance with radio frequency(RF-{LSR) on the two polycrystalline samples of Haldane gap systems: Ni(C2H8N2hN02(CI04) (NENP)
and NiC 20 4 2·2MIz (2MIz = 2-methylimidazole). In
these systems, an enhancement of the muon spin relaxation was observed at low temperatures as usual. 2-4) In
this report, we demonstrate only the results ofRF-{LSRin the NENP (whose gap energy Eg rv 14 K 5 )).
The RF-{LSR measurements were carried out using a pulsed surface muon beam at the RIKEN-RAL
Muon Facility in the UK. The frequency was 47.0 MHz.
Double ratio is defined as A onlAoff , where Aon,off ==(N~n ,off _ N~n ,off) /(N~n ,off + N~n,off). The N~n ,o ff andN~n,off denote the integrated positron counts in theforward and backward directions with the RF poweron or off, respectively. We analyzed the longitudinal
field dependence of the double ratio (resonance curve)
using a Lorentzian function. The resonance position
is defined as the field at which resonance curve depicts the minimum. In this experimental condition,
the resonance position in non-local field is estimatedas 3468 G.
In Fig. l(a) , the resonance curves measured at 2.7 K
and 80 K are shown. The resonance positions at 2.7 K
and 80 K are 3470 G and 3468 G, respectively. Thus,
the average local field at the muon site changes only
rv2 G even at the low temperature (2.7 K). This isinconsistent with the result of the previous {LSR measurement, which showed the magnitude of local field
rv90 G. 3 ) The width of the resonance curve is wider
and the depth is much smaller at 2.7 K than at 80 K.
Figure 1 (b) shows the temperature dependence ofthe resonance position. The inset shows the full widthat half maximum (FWHM) of the resonance curve. As
the temperature decreases below rv20 K , the resonanceposition shifts to a slightly higher field. The FWHM ofthe resonance curve becomes wider at the temperature
below rv20 K , indicating that the distribution of local
fields becomes wide. According to Ref. 4, the temperature at which the muon spin relaxation in zero fieldstarts to be enhanced also is rv20 K. 4)
From these results, we have attempted to consider

114

0

'p

Q2

.£
.t:l
::s
0
0

0.9

\

V

0.8

0.7
3440

3400

3480

3520

Logitudinal field (G)
3474

i~D

(b)

~3472
'p

'~3470 t+
8
~

=
~3468

++

Q)

100

+

40 60
T(K)

80

100

+

~

20

20

40

60

80

100

T(K)

Fig. 1. (a) Resonance curves at 2.7 and 80 K. Solidand dotted lines are the results of fits to a Lorentzianfunction, and the broken line represents a base line.
(b) Temperature dependence of the resonance position.
The inset shows the FWHM of resonance curves.

the cause of enhancement of the muon spin relaxation.
In some insulators, a part of implanted muons is boundwith an electron to form a muonium. In this sample,
most of implanted muons is unbound at high temperatures. As temperature decreases, a part of muons isbound with electrons. Such muons do not show resonance in this experimental condition, while they cause
a strong muon spin relaxation . The others remain unbounded and the change of local field at the unboundmuon site is quite small.
We have measured the RF-{LSR also in NiC 20 4
2·2MIz, and have obtained similar results as the caseofNENP.
At present , the cause of a slight change of the resonance position and of the increase of FWHM are still
unclear. Further study is necessary in order to clarify the whole picture of the anomalous enhancementof muon spin relaxation in the quantum spin systems.
References
1) A. Sohma et al.: J. Phys. Soc. Jpn. 64 ,3060 (1995).
2) A. Fukaya et al.: Hyperfine Interact., in press .
3) B. J. Sternlieb et al.: J. Mag. Mag. Mater. 104/107,
801 (1992) .
4) M. Motokawa et al.: Physica B 177, 389 (1992).
5) J. P. Renard et al.: Europhys. Lett. 3 , 945 (1987).

RIKEN Accel. Prog. Rep. 32 (1999)

Spin Dynamics of 2D K agorne Antiferromagnet,
rn-MPYNNBF 4, Studied by fLSR
I. Watanabe, N. Wada,* S. Ohira, and K. Nagamine

Two dimensional (2D) Kagome antiferromagnet,
called m-MPYNNBF 4 , shows a spin dimer state with
S = 1 w~ich is formed below 23 K by two radical electrons through an intra-dimer ferromagnetic
interaction. 1 ,2) The ground state has been found to
be non-magnetic by our previous muon spin relaxation(p,SR) measurement at KEK-MSL. 3 ,4) But, because of
the restriction of statistics of the muon events, detailsof the dimer spin dynamics have not become clear yet.
We have therefore carried out zero-field (ZF) p,SR measurements at the RIKEN-RAL Muon Facility in the
UK to clarify these problems by using an intense pulsed
muon beam.
Figure 1 shows the ZF-p,SR time spectrum of mMPYNNBF 4 at 0.30 K. The total number of the muon
events was 100 million. Depolarization behavior due
to the randomly distributed static fields of 19F nuclear dipoles was observed also in the previous p,SR
at KEK-MSL. 3 ) Precession of the muon spin with asmall amplitude was clearly observed in this system,
proving the existence of the Fp,F state which is likethe hydrogen bonding state.
>.
1.0
I-<

m-MPYNBF4V

ZF-J.lSR Time Spectrum
O.30K

~
>.

<'" 0.5

using the above analysis function.
Figure 2 shows the temperature dependence of thefluctuation rate of dynamical Kubo-Toyabe term in theanalysis function . The fluctuation rate is almost constant below about 10 K and shows a linear temperature dependence above 20 K. The linear temperaturedependence of the fluctuation rate implies that the origin of fluctuating internal field at the muon site is notdue to the thermal activation of muon hopping.
It is suggested from the susceptibility and heat capacity measurements that two radical spins can form
the dimer state below about 23 K by the intra-dimer
ferromagnetic exchange interaction, JO .1,2) In this case,the fluctuation frequency of the internal field below
23 K is dominated by Jo, resulting in the temperatureindependent depolarization rate of m~on spin. This
ferromagnetic exchange energy is overwhelmed by thethermal fluctuation energy above 23 K. In this case,the fluctuation frequency is dominated by the thermalenergy of kB T instead of J o, resulting in the linear
depolarization rate with temperature. The observed
temperature dependence of the fluctuating rate of themuon spin shows a good agreement with the spin dynamics feature which is expected from the susceptibility and heat capacity measurements. Thus, our p,SR
result has revealed the existence of the dimer spin stateand its spin dynamics.

"'0
<l)

.~

,-...

~

~

§
0

Z

0<00

0'18 00'

0

0

6'0 00 0

0

00
0

0.15

I

u
<9

o~o 0

Q)
<Il

0

2: 0.12 -

-

Q)

0

5

10

15

20

Time (p,sec)Fig. 1. ZF-J.LSR time spectrum of m-MPYNNBF 4 at
0.30 K. The total muon events was 100 million.

~
~
!=:

0.09 -~

0.06 ;:0

.S
N

0

0

0

0

m-MPYNNBF4o Dynamical K-T

'C
ro

'0

-

<)

0.03 !--

0..
Q)

Recovery of the asymmetry at the region after 7 p,sec
was clearly observed. This recovery is described as the"~-tail" of the Kubo-Toyabe function. The "~-tail"shows a slow depolarization behavior due to the dynamically fluctuating local fields at a muon site. The
time spectrum was analyzed by utilizing the following
analysis function: A 1e(-A 1 t) i3 + A2GZ(~, t, .\2)' The
first term describes the muons which interact with surrounding electrons. The second term is the dynamical Kubo-Toyabe function, while .\2 is the dynamically fluctuating rate of internal fields at the muonsite. Solid line in Fig. 1 is the best-fit curve fitted by

0

0.0

I

0

50

100

Temperature (K)Fig. 2. Temperature dependence of the .\2 of dynamical
Kubo-Toyabe term in the analysis function used.
References
1) K. Awaga et al.: Phys. Rev. B 49 , 3975 (1993).
2) N. Wada et al.: J. Phys. Soc. Jpn. 66, 961 (1997).
3) 1. Watanabe et al.: Phys. Rev. B 58, 2438 (1998).
4) 1. Watanabe et al.: RIKEN Accel. Prog. Rep. 31, 111(1998) .

Graduate School of Arts and Sciences, University of Tokyo

115

RIKEN Accel. Prog. Rep. 32 (1999)

p,SR Studies on 4-Arylmethyleneamino-TEMPO
S. Ohira, I. Watanabe, T. Ishida, * T. Nogami,* and K. Nagamine
Organic radical magnets having a 2,2,6,6-tetramethylpiperidin-l-yloxyl (TEMPO) group are known
to have a strongly 2D structure in their N-O network.
Radicals are localized at the N-O site and contributeto the magnetism of the system. A long-range magnetic ordered state in some TEMPO derivatives wasobserved by various methods. I}
Our previous two J.LSR experiments performed on
p-chlorobenzylideneamino-TEMPO (p-CI-C 6 H4 -CH =N-TEMPO, 1) and on p-phenylbenzylideneaminoTEMPO (p-Ph-C 6 H4-CH = N-TEMPO, 2) showed
clear oscillation signals below 275 and 225 mK, respectively; thus indicating the existence of a long-range
ferromagnetic ally ordered state. 2 ) These two radicals
have a quite similar structure in the N-O sheet. The
distance between the sheets of 2 is longer than that of
1. A mechanism for the intra-sheet ferromagnetic interaction has already been suggested based on the overlap of the molecular orbitals.3 ) On the other hand, themechanism of the inter-sheet magnetic interaction isstill unclear. In order to study critical behavior of thesesystems , we have carried out longitudinal field (LF)
and transverse field (TF) J.LSR measurements down toabout 0.30 K.
The experiments were carried out at the RIKENRAL Muon Facility in the UK. Figure 1 (a) and (b)show the LF-J.LSR time spectra of 1 at 0.30 K and 2 at
0.32 K , respectively. The LF decoupling behavior for
1 reveals the existence of random static internal fields
at the muon site. The width of the internal field distribution at 0.30 K increases with increasing LF andeventually saturates.4) A random internal field was notobserved in the LF spectra of 2. The muon spin was
decoupled under LF above 50 G. The decoupling behavior of 1 at 1.5 K is quite similar to that of 2 asshown in Fig. 1 (b). In the case of 2 , the measured temperature was too high to observe such an LF-induced
secondary field.
Because the shapes of both samples are needle-like,
two axes directions perpendicular to the longitudinal
direction are random for LF, while the other axis canbe parallel to TF. In order to clarify the dependence offield direction on the magnetic properties of the system
at above the Curie temperature Te , TF-J.LSR studies
were carried out on these systems. Two precession frequencies of the muon spin were observed under the TF.
The muons which precess with the frequency "(p,HTF
make up one large amplitude component, where "(p, isa gyro magnetic ratio of muon. The other oscillation
component showed a higher frequency with a smaller
amplitude. Figure 2 shows the temperature depenUniversity of Electro-Communications

116

(a)
0.15

A: 100 G
0: 200 G.: 300 G

0 : 0 G
. : 25 Gt:; : 50 G

>.
s...

+'
(])

8
8
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0 .10

C/l

<

'0

2

()
(])

s...
s...

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0 .05

u

0.00

2

0

4

3

Time [J.Ls]

(b)

0 .15

>.
s...

+'

0

oG

•

50 G

t:; : 200 G
A: 300 G

(])

8
S
>.

0 .10

C/l

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'0
(])

+'
()

(])

s...
s...

0.05

0

u

2 3 4

Time [,us]Fig. 1. Time spectra of (a) 1 at 0.30 K and (b) 2 at
0.32 K.

80

o

TF

70

~
>,
()

60

C

<1>
;j

0'

<1>

s...

40 G

o

50

"'"'
40

o

t •

00

0

o

o

30
0 .2

0 .4

0.6

0.8

Temp e rature [K]Fig. 2. Temperature dependence of the precession frequency which is not due to the diamagnetic muon spin
precession, under TF of 40 G. Open and closed circles
respectively show the results for 1 and 2 .

dence of the latter precession frequency under the TF
of 40 G, for both derivatives.
The internal fields observed in LF- and TF-p'sR havethe similar magnitude and temperature dependences.
Therefore, both the random static internal fields observed in LF-p'sR and the additional field in TF-p'sR
are expected to originate from the same magnetic property. Either a low-dimensional fluctuation or else a hyperfine field from the radical and the electron whichforms muonium (J-L+ +e-) can be a candidate to explain
the unusual magnetic state just above Tc observed inthese J-LSR studies.
References
1) T. Nogarni et al.: Chern. Lett. 1995, 635.
2) R. Irnachi et al.: Chern. Lett. 1997, 233.
3) T. Nogarni et al.: Bull. Chern. Soc. Jpn. 69, 1841 (1996).
4) S. Ohira et al.: to be submitted.

117

RIKEN Accel. Prog. Rep. 32 (1999)

Muon Studies on Weak Organic Charge
Transfer Compounds
R. M. Macrae, I. D. Reid,*1 R. Kadono, K. Nagamine, and J. U. von Schiitz*2
Weak organic charge transfer compounds formed by
1 : 1 co-crystallisation of planar aromatic molecules(Fig. 1) are of interest from the perspective of molecular dynamics and, through the behaviour of triplet excitons in these systems, as models of low-dimensional
excitation transport. I ) Muon techniques offer a unique"handle" on these properties in that a single j.L+generated free radical probe can be utilised to study
both thermal excitations and molecular reorientational
dynamics (using conventional j.LSR techniques) andphotoinduced behaviour and excitonic dynamics (using synchronous excitation j.LSR2)), separating two
influences the effects of which are usually superposed. Initial tests were carried out on the system
anthracene/tetra- cyanobenzene (A/TCNB) at PSI
and RIKEN, and preliminary reports of the results areavailable. 3 ) To summarise, j.LSR is sensitive to quite
subtle changes in the molecular dynamics, and also apparently- to changes in the degree of static order.
Synchronous excitation studies await the developmentof a suitable laser setup at RIKEN /RAL.

Anthracene (A)

-0.08

*

>. -0.09

Hexamethylbenzene (HMB)

N
NCXX
I~
NC
.#

Naphthalene (N)N

Subsequently, studies on A/TCNB were extended
to include temperature-dependent high-resolution TF
j.LSR on a single crystal sample, and ALC-j.LSR measurements were carried out on polycrystalline samplesof two other systems in which the "acceptor" molecule
remains TCNB, but the "donor" molecule has been
replaced by naphthalene (N /TCNB) and hexamethylbenzene (HMB/TCNB) respectively. (Through systematic changes of donor and acceptor, the properties
can to a certain extent be "tuned".) The free radical
species formed were identified through their characteristic values of B o, the b.M = 1 lineshape envelope
origin, by comparison with values of AJ.L' the isotropic
component of the muon-electron hyperfine coupling ,to which it is proportional. Values were taken both*1

118

11 -0.10

E
S

-0.11

r,

~\
II

\

v.
~
t-f-..,f-H-H+++++++-+-I-+-1f-H-++-++-+++++-H~ -0.10<-0.11

1.2.4.5-Tetracyanobenzene (TCNB)

Fig. 1. Donors and acceptors.

*2from the experimental literature 4 ,5) and from the results of first principles calculations using the densityfunctional-based method B-PW91. 6 )The results were striking in two major ways. Firstly,
in no case was the adduct to the TCNB moiety observed. This can be only partially due to the somewhat greater steric freedom of the donor species andthe concomitant stabilisation of radical adducts to it,
and must have implications with regard to the formation mechanism of the radical, suggesting that in systems of this type, at least in the solid state, ionic intermediates are not involved. Secondly, the results, particularly in N /TCNB in which the lineshape is highly
complex and undergoes subtle temperature-dependentchanges (see Fig. 2), indicate that ALC-j.LSR is particularly effective in distinguishing changes in static orderin these systems, implying, in the cases of A/TCNB
and N /TCNB, in which the parent molecule lies in an
only slightly unsymmetric double potential well, that
small intermolecular effects have a considerable influence on the radical hyperfine interaction.

Paul Scherrer Institut, Switzerland
3. Physikalisches Institut, Universitiit Stuttgart, Germany-0.12- O. 13 L-I.-L-J......\-L....L-L..-I......L....L..J......L....l-./--'-'--JL....L...J---'--L....L....L....L...L....J......L....L-.L.J
10000
12000
14000
16000
16000
20000
22000

Field/G

Fig. 2. ALC-j.tSR spectra for N /TCNB at 200 K and 50 K.

References
1) J. Krzystek and J. U. von Schutz: Adv. Chern. Phys.
86, 167 (1993); and refs. within.
2) R. Kadono, A. Matsushita, R. M. Macrae , K.
Nishiyama, K. Nagamine: Phys. Rev. Lett. 73 , 2724
(1994).
3) R. M. Macrae, T. M. Briere, C. J. Rhodes , 1. D. Reid,
J. U. von Schutz: Proc. Int. Workshop on JHF Science (JHF98), in press; also see PSI and RIKEN reports
1997.
4) 1. D. Reid and E. Roduner: Struct . Chern. 2,419 (1991).
5) E. Roduner: Hyperfine Interact 65, 857 (1990).
6) L. A. Eriksson, O. L. Malkina, V. C. Malkin , and D. R.
Salahub: J. Chern. Phys. 100, 5066 (1994).

RIKEN Accel. Prog. Rep. 32 (1999)

Development and Test of the RF-ILSR System at RAL
I. Watanabe, F. L. Pratt, and K . Nagamine

Muon spin resonance technique using a radio frequency (RF-J.LSR) field together with a static longitudinal magnetic field (LF) is a powerful method to investigate hyperfine interactions at muon sites in magnetic
materials. I) A pulsed muon facility has certain advantages in carrying out the RF -J.LSR. The detail design of
the RF -system and the first report of the development
work have been reported in the previous RIKEN Accel.
Prog. Rep.2 ) In this letter, we report test results of applications with a real muon beam using the developed
RF system.
The RF-J.LSR on carbon powder was tested firstto check the effect of the temperature on the probe.
Figure 1 shows the field dependence of the RF-J.LSR
time spectrum of the carbon powder at 280 K. The
output power from the RF amplifier was 50 Wand the
RF frequency was 47.000 MHz. The RF pulse width
was 30 J.Lsec. The 4He gas with the pressure of 1 atm
was used as an exchange gas to cool down the probe.
The absolute value of the LF is not correct because of
an offset on a read-back system of the field.
Clear muon spin precession pattern around HI wasobserved near the resonance field of 3.5 kG. The precession frequency showed a minimum on the resonance condition. The estimated strength of HI was
about 6 Gauss because of the restriction of the discharge. It was found that the discharge was suppressed when the N 2 gas with the pressure of 1 atm
was used instead of the 4He gas.
In this case,about 17 Gauss of the HI was obtained in maximum. However, 4He gas must be used below about
80 K to cool down the probe.
As long as the

Carbon Powder
280K, 47MHz, SOW
34800
o

4He gas is used, the HI is restricted to be a couple ofGauss because of the discharge . This restriction is oneof the problems which we have to solve out as soon as
possible.
The resonance frequency and other physics information are obtained by calculation of the double ratio of
the time spectrum, i.e. the ratio of the time averaged
asymmetry in field to the time averaged asymmetry inzero field. Figure 2 shows a resonance curve which was
determined by the double ratio calculation at 280, 100
and 5.3 K. The time range for averaging was from 0 to
15 J.Lsec. The resonance position was obtained from thefitting of the resonance curve assuming the Lorentziantype function. Tanking into account the offset field, it
was found that the resonance position showed the zerotemperature shift.
The width of the resonance curve is mainly determined by the inhomogeneity and the amplitude of HI.
If the RF coil deforms at low temperatures, the deformation causes a change in the homogeneity of HI
leading to a change in the resonance curve width. However, no evidence of the deformation of the RF coil wasobserved down to 2 K.
The probe was also tested with other materials as
follows.
(1) Oxides:
La-Co-O, La-Sr-Nd-Mn-O(2) Low dimensional materials:
TI-Cu-CI, Ni-C-O, NEMP
(3) Organic materials:
polyaniline, polybutadiene,
polypyridine, cytochrome-C
On behalf of these systems, a representative test result of the RF-J.LSR study on LaCo0 3 is simply reported in this letter.
LaCo0 3 shows the temperature dependence of the

0

1.2
0

Carbon Powder, 47MHz, SOW

1.0

'.0
~

~

0.8

(L)

:c::s 0.6
0o 280K
6. lOOKo S.3K

0 0.4
35400

0.2
3480 3490 3500 3510 3520 3530 3540 3550

o

246

8

10

Time (J.Lsec)
Fig. 1. Field-dependence of the RF-J.LSR time spectrumof the carbon powder at 280 K.

Field (G)Fig. 2. Resonance curve of the carbon powder sample
at 280, 100 and 5.3 K obtained from the double ratio
calculation.
119

Co-spin state, going from a high-temperature highspin state (8 = 1) to a low-temperature low-spin state(8 = 0). Detail of the physics background is reported
in other papers. 3 - 5 ) The susceptibility of the systemshows a maximum around 90 K and vanishes below
20 K. Thus, this system is a good example to checkthe performance of the newly developed system andto test whether the RF system can detect a change inthe magnetic properties from the measurement of the
diamagnetic shift of the resonance frequency.
Figure 3 shows the resonance curves obtained at 280,
100 and 5.6 K. "Solid lines in the figure are the best fit
results. Figure 4 shows the temperature dependenceof the resonance frequency. A small shift in the positive direction was observed, indicating the existence ofa positive hyperfine field at the muon site. The shift
is less than 1%, but it is still observable. This resultshows that the system can be used to measure diamagnetic shifts as small as 0.1 %.
The test results show good performance of the developed RF probe around 50 MHz. However, it was foundthat there were still some problems and requirementson this test probe as follows:(1) Much higher H I is required(2) Low frequency RF-J.LSR system is desired(3) Discharge should be prevented
The requirement (1) is correlated to (3) because
the discharge is the factor restricting the maximum
voltage applied to the RF coil.
This restriction

LaCo03 • 47MHz. sow

1.0

.9
~

~

0.8

~

.go 0.6o 280K
b.1OOKo S.6K (lOOW)o

0.4

0.2 '----'---'---''---''---'------'______'____L____L--L--L--.L---'-----J
3480 3490 3500 3510 3520 3530 3540 3550

Field (G)Fig. 3. Resonance curve of LaCo0 3 at 280, 100 and 5.6 K.
The RF frequency was 47.000 MHz.

120

3520.01

LaC~. 47.000MHz,?

3517.5 f-

3515.0 -

1

sow

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0

8
·_·_·-t:r·_·_·_·_·_·_·_·_·_·_·_·_·_·.A..·_·_·_·- ts ·fa 3512.5 r- CaJbon(O-shift)

-

-

=

o

VJ

a)

~

3510.0 '--'--'--.J.....J.....LLJ.JI'------'---'--'--'....L..L.Ll.~
1____L______'___"__..1
10100

Temperature (K)Fig. 4. Temperature dependence of the diamagnetic shift
in LaCo0 3 .
suppresses the strength of HI. We need more treatments and tests on matching capacitors to prevent thedischarge. The higher HI more than 20 Gauss is especially needed in the time-delayed RF-J.LSR measurement, changing the timing of the RF trigger. The time
evolution of the state of the muon can be investigatedby this measuremant.
The requirement (2) was needed to carry out thefield dependence (RF frequency dependence) of the
RF-J.LSR. The electric circuit of the probe has to bechanged to another type when the RF frequency islower than about 20 MHz, which corresponds to an
external field of about 2 kG. The "high-impedance"
matching method adopted in the present test probe is
not efficient for the lower frequency, so that we haveto use a "low-impedance" matching method in which
the matching capacitor and the RF coil are connected
in series. The field variable RF-J,tSR is the next stepof the development work which will be started soon.
References
1) K. Nishiyama: in Perspectives of Muon Science, edited
by T. Yamazaki, K. Nakai, and K. Nagamine (NorthHolland, Amsterdam, 1992), p. 199.
2) 1. Watanabe et al.: RIKEN Accel. Prog. Rep. 31, 116(1998) .
3) K. Asai et al.: Phys. Rev. B 50 , 3025 (1994).
4) M. Itoh et al.: J. Phys. Soc. Jpn. 64,3967 (1995).
5) M. A. Korotin et al.: Phys. Rev. B, in press

3. Radiochemistry and Nuclear Chemistry

RIKEN Accel. Prog. Rep. 32 (1999)

Comparative Regional Uptake Behaviors of a Radioactive
Multitracer in Brain of the Young and Aged C57BL/6N MiceR. Amano, S. Oishi, T. Tarouda,* and S. Enomoto
The unique properties of cerebral capillary endothelial cells restrict the passage of water and nutrientsselectively between blood and brain, by forming theblood-brain barrier (BBB). We focused on studies of
the transportation of various trace elements throughBBB and of their retainment in the brain, utilizing theradioactive multitracer technique. 1- 4) In the preceding
reports , we compared the uptake behaviors of radioactive Sc, Mn, Fe, Co, Zn , Se, Rb, and Zr in the brain
and other organs of C57BL/6N mice. 3,4) The present
work aims to study regional cerebral uptake behaviors
of a multitracer of 46Sc, 48V, 54Mn, 58Co, 65Zn, 75Se,
83Rb, and 88Z r among 7 brain regions (corpus striatum, cerebellum, cerebral cortex, hippocampus, midbrain, olfactory, and pons and medulla) and blood of
the young and aged C57BL/6N mice. The multitracer
solution is expected to give us new findings concerning the relationship between the regional BBB function
and the uptake behavior of some trace elements.
Four groups of male C57BL/6N mice having different ages (6, 10, 28, and 52 weeks after birth) wereused. The mice had been purchased from Charles
River Japan, Inc. These groups were then housed in
the plastic and steel cages at the Laboratory for Experimental Animals, Kanazawa University. They were
fed on a standard laboratory diet and had free accessfor drinking water during more than 1 week prior toadministration of multi tracer. Five of the mice wereused in each group. A carrier-free multitracer solution was obtained from an Ag (purity: better than
99.99%) target irradiated by the heavy-ion beam fromRIKEN Ring Cyclotron. The multitracer solution was
prepared after the method by Ambe et a1. 1 ,2) at the Radioisotope Center, Kanazawa University. The solution
contained 12 radioisotopes of 10 elements at 3 weeks
after the beam bombardment. For injection to mouse,
the physiological saline solution (O.OOlN HCI, pH 2- 3)
containing the radioactive multitracer was prepared.
An appropriate amount (0.2 ml) of the multitracer
solution was intraperitoneally(i.p.) injected into eachmouse. At 48 h after this i.p. injection, the mice weresacrificed under ether anesthesia, and about 0.2 ml ofblood was collected in a test tube. Then, brains were
excised and separated into 7 regions (corpus striatum,
cerebellum, cerebral cortex, hippocampus , midbrain,
olfactory bulb, and pons plus medulla). These separated regions were weighed immediately and freezedried. The dried samples were measured by 'Y-ray
spectrometry with pure Ge detectors in reference toan appropriate standard to obtain "the regional upAsanogawa General Hospital, Kanazawatake rate" (percentage of injected dose per gram of theregion: %dose/g of region) for different tracers. We
carefully avoided the adhesive water in weighing theregional samples.
As the results, the multitracer solution enabled a simultaneous tracing of the elements Rb, Zn, Se, Mn, Sc,
and Zr elements in each region and a strict comparisonof their biobehavior. The regional uptake rates of Rb,
Zn, Se, Mn, Sc, and Zr tracers at 48 h after the i.p.
injection are shown in Fig. 1. Rubidium, Zn and Se inaged mice were found to be distributed fairly evenly inthe regions, and the uptake rates of these elements arehigher in aged mice than in young ones. However, theuptake rates of Mn, Sc, and Zr tracers in aged mice
have a fairly-large difference among regions, and thoseof Sc and Zr in aged mice are higher than in young
ones, and highly concentrated in certain regions. The
behaviors of ·Sc, Mn, and Zr may be ascribed to thedegenerative variation of the function of BBB due toaging.

10=·i0...'"'
0

~ 1
~

't:I

~

10 ~--------~10~--------~

Rb

Zn

Se

~
• Striatum• Cortex
Hlppocampua

0
0

,.

Cerebellum
Pon8+Med.

10 0 10 20 30 40 SO 60 10 0 10 20 JO 40 SO 60 1 0 10 20 JO 40 SO 60

Mn

o 10 20 JO 40 50 60

Sc

0 10 20 JO 40 SO 60

Zr

0 10 20 JO 40 SO 60

Age (week)

Fig. 1. Aging effect on the regional uptake rates of 6 elements in the brain of normal C57BL/6N mice.
References
1) S. Oishi et al.: J. Radioanal. Nucl. Chern. 239, 411(1999) .
2) R. Amano et al.: On line Proc. 5th Internet World
Congr. on Biomedical Science '98.
3) R. Amano et al.: RIKEN Accel. Prog. Rep. 31, 126(1998).
4) S. Oishi et al.: RIKEN Accel. Prog. Rep. 31, 127 (1998).
121

RIKEN Accel. Prog. Rep. 32 (1999)

Metabolic Study of Trace Elements in Se-Deficient Rats (III)R. Hirunuma, K. Endo, S. Enomoto, S. Ambe, and F. Ambe
Selenium has a property to interact with several metals in mammals. 1 ,2) Therefore, it is quite interestingand important to compare the distribution of traceelements in various organs between Se-deficient andSe-sufficient rats. However, no systematic study has
been performed on the behavior of trace elements in
Se-deficient rats. In the present study, the uptake anddistribution of trace elements in control and in two
types of Se-deficient rats were examined by the multitracer technique, a useful technique to evaluate thebehavior of many elements under the identical experimental condition. The rats bred on Se-deficient dietfrom fetus were used in experiments as Se-deficient (I)rats. Se-deficient (II) rats were fed on Se-deficient dietfrom the weanling period.
A multitracer solution containing 20 elements of radioisotopes was prepared from an Ag target irradiatedby a heavy-ion beam of 135 MeV/nucleon accelerated
by RIKEN Ring Cyclotron. Wistar male rats bornto Se-deficient dam were fed on Se-deficient diet (produced by Oriental Yeast Co., Ltd.) for 12 weeks after birth to convert them Se-deficient rats (I). Wistar
male rats (4 weeks old) were fed on Se-deficient dietfor the next 8 weeks to convert them Se-deficient rats
(II). Four-week-old Wistar male rats were fed on Sesufficient (containing 0.2 ppm of Se) diet for 8 weeks
to convert them control rats. The multitracer solution was injected intravenously (0.1 ml/rat). The rats
were sacrificed at 72 hrs after injection, and the radioactivity of their organs was determined by a ,-ray
spectrometry. The observed ,-rays were assigned interms of their energies and half-lives. The individual
behavior of Be, Na, Ca, Sc, V, Cr, Mn, Fe, Co, Zn, Ga,
As, Se, Rb, Sr, Y, Zr, Tc, Ru, and Rh was examined.
The influence exerted by Se-deficiency was observedon the behavior of Se, As, Fe, and Sc in various organs of Se-deficient rats (I) or (II). Figure 1 shows
the uptake of Se in the brain, testicles, and liver of
the Se-deficient (I), (II), and control rats. The uptake of Se was higher in the brain of the Se-deficient
rats (1) and (II) than in that of the control ones. On
the other hand, the uptake of Se in the testicles washigher only for the Se-deficient rats (II) than that forthe control ones. And, there was almost no influenceon the uptake for the Se-deficient rats (1) . In the liver ,the uptake of Se in the control rats was the highest,
and that in the Se-deficient (II) was higher than thatin the Se-deficient ones (1). It is suggested that the organs such as brain and testicles need Se even a small
amount: Se plays a very important and acute role inthese organs. It is considered that the morphology ofthe spermatozoa of Se-deficient rats (I) has changed
because they were maintained for a prolonged period
on a Se-deficient status. As a result , we suggest thatthe spermatozoa of Se-deficient rats (1) can not uptake
Se.

122

Brain

:~::::I;:EJ~"trolo

EJ t lTesticles

1

2
Uptake (%)

3

Liver

~

0

10

20
Uptake (%)

30

0

10

20

30

Uptake (%)

Fig. 1. Uptake of Se in the brain, testicles, and liver of
the Se-deficient (1), (II) , and control rats.
The characteristic results obtained on As, Fe, and Sc
in the liver are shown in Fig. 2. The uptake of As, Fe,
and Sc was larger in the liver of the Se-deficient rats (I)than that of the Se-deficient (II) and control ones. Selenium enhances As excretion in to bile in the rats.3 ,4)The observed accumulation of As in Se-deficient rats
(1) suggests that the bile excretion of As was decreased
by Se-deficiency. Increase of Fe uptake in the liver of
Se-deficient rats (I) suggests an accumulation of the
Fe-binding protein, such as catalase or ferritin. Interestingly, the uptake behavior of Sc and Fe was similarin the liver of the Se-deficient (I), (II) and control rats.
One of the reasons why the uptake behavior is similar
between Sc and Fe is presumably due to the similarityof their ionic valence and of their ionic radii (0.73 A for
Sc 3 + and 0.64 A for Fe3 +).
The behavior of trace elements except Se in the Sedeficient rats (II) was not different from that in thecontrol ones. The uptake of As, Fe, and Sc was higher
in the Se-deficient rats (I) than in the control ones. It
is suggested that the metabolism of these elements is
affected by Se-deficiency for fetus.

S:d::~::'(::E> , >: I e--l Fl
Cootrol

As

.. ..

o 2.5

5

7.5 10Uptake (%)

U
0

10

U

20

30

Uptake (%)

40

0

10

20 30 40

Uptake (%)

Fig. 2. Uptake of As, Fe, and Sc in the liver of the
Se-deficient (1), (II), and control rats .
References
1) T . Urano, N. 1mura, and A. Naganuma: Biochem. Biophys. Res. Commun. 239 , 862 (1997).
2) J. P. Berry, L. Zhang, and P. Galle: J . Submicrosc.
Cytol. Pathol. 27, 21 (1995).
3) O. A. Levander and C. A. Baumann: Toxicol. Appl.
Pharmacol. 9 , 98 (1966) .
4) O. A. Levander and C. A. Baumann: Toxico!. Appl.
Pharmacol. 9 , 106 (1966).

RIKEN Accel. Prog. Rep. 32 (1999)

Multitracer Study on the Soil-to-Plant Transfer of Radionuclides
in Brassica rapa L. yare perviridis Bail (Komatsuna)at Different Growth Stages
S. Ambe, T. Ozaki, S. Enomoto, and T. Shinonaga
The transfer factor, which is defined as the ratio of
the radioactivity concentration in plant to that in soil,
is widely used for the evaluation of the uptake of radionuclides by plants from the soil. The transfer factor
is greatly affected by growth conditions such as composition of soil, particle size of soil, soil pH, climate, andso on. Most of the transfer factors have been reported
for the edible parts of mature plants. Some leafy vegetables are harvested as foods from young to mature
growth stages. It was shown that the translocation
rate of I34CS from leaves to tubers is greatly affectedby the development stages when radioisotopes are applied to potato plants. I} This suggests the importanceof studies on the uptake of radionuclides by various
plants at different development stages. However, thevariability of transfer factors depending on the growthstage has not been studied comprehensively. In thisstudy, the uptake of radionuclides of Na, Mn, Co, Zn,
Se, Rb, Sr, Y, Zr, Tc, Rh, and Cs by komatsuna (Brassica rapa L. var. perviridis Bail) was determined simultaneously by the multitracer technique.
Commercially available Kureha soil was mixed wellwith the multitracer solution and the pH of the soil
solution (soil water volume ratio: 1 : 2.5) was determined to be 6.0. About ten seeds of komatsuna weresown and cultured on the soil ( about 2 kg dry weightof soil) in a pot. Five pots for the transfer factor study
and three pots as control were placed in a plant-growthchamber maintained at 23°C and 70-80% relative humidity under about 13000 lx-light exposure from fluorescent lamps 16 h a day. The komatsuna plants weregrown for 14, 20, 26, and 33 days from sowing. Two to
4 plants on day 14, 2 plants on day 20, and one planteach on days 26 and 33 were harvested, and then they
were divided into leaves and roots. The samples weredried at 60°C for one day. The dry samples mounted
in a plastic vessel (60 mm¢» were subjected to ,-raymeasurement.
The transfer factors were obtained as average values of five samples with standard deviations. Figure 1
shows the time dependence of the transfer factors ofthese elements except Co, Se, Y, Zr, and Rh. The
decrease in the transfer factors from l.9 to l.3 for
Rb, from 50 to 17 for Tc, and from 0.016 to 0.0065
for Cs was observed in the leaves of komatsuna withincreasing culture period with the multitracer, while
those of Na (l.3), Co (0.03), Se (0.06), and Sr (0.28)
in leaves remained almost constant. In contrast, thetransfer factor of Mn increased from 0.11 to 0.25 withtime. The transfer factor of Zn (0.52) on day 14 (the

2.0
(A)

1.5

j
Ii

1.0

";I

~

0.5

0.0
60
(8)

o+----,----.--~__,_--f
0.020,--------,
(e)

0.015

0.010

0.005

0.000+----,-----,--.,...--.--1
0.8..--------,
(0)

0.6

~

"'ii 0.4

1>-

0.2

O.O+----,----.--~____._----l

10

15

20

2S

30

35

OaYSlfter SOIMng

Fig. 1. Time dependence of the transfer factors of N a(0), Rb (0), and Sr (0) (A), Tc (B), Cs (C), and Mn(0) and Zn (0) (D) obtained from komatsuna leaves.
If error bars are not shown, the standard deviations arewithin symbols.

youngest stage) was higher than that on other days, although the standard deviation was large. Technetium
gave the highest transfer factor among the elements
studied, followed by a marked decrease in the transfer
factor with time. The radioactivities of Y and Zr in theleaves collected from the plants cultured for 14, 20, 26,
and 33 days were below the detection limit. A small
amount of Rh was found in the leaves of the plants
cultured for 33 days and its transfer factor was 0.003.
Extraction of multitracer from the soil was carriedout in order to study the correlation between the transfer factor and the aging effect of the tracers in soil. The
transfer factors for leaves and roots exhibit no correlation with the extractability of the tracers from soil.
References
1) T. K. Riesen, J. Egli, and R. Y. Andres: Radiat. Environ. Biophys. 36, 293 (1998).

123

RIKEN Accel. Prog. Rep. 32 (1999)

Reduced Uptake of Mn in Cd-Resistant Metallothionein
Null Fibroblast
S. Himeno, T. Yanagiya, N. Imura,* R. Hirunuma, and S. Enomoto
Cadmium (Cd) is a heavy metal known as a causative agent of Itai-itai disease. Orally ingested Cd ispreferentially accumulated in the kidney, thus leading
to a characteristic nephrotoxicity known as Fanconi's
syndrome. Metallothionein (MT) is a low-molecularweight cysteine-rich protein that can efficiently bindto metals such as Zn, Cu, and Cd. Important rolesof MT in the detoxification of Cd have been well
documented. However, other factors that can modulate the toxicity of Cd have not yet been fully elucidated. Recently, MT null mice in which MT-I and II
genes were disrupted have been developed. 1 ,2) We established a SV 40-transformed embryonic fibroblast cellline from MT null mice so as to obtain apparently immortalized cells lacking MT expression. 3 ) Furthermore,
we developed a Cd-resistant cell line from the SV 40transformed MT null cells to investigate the resistancefactors to the Cd irrelevant to MT. This Cd-resistantMT null cells (Cd-r) showed a markedly reduced accumulation of Cd compared to the parental cells. In thepresent study, we have investigated the uptake of various kinds of metals in Cd-r cells using a multitracer
technique, and found a marked decrease of Mn uptake
in Cd-r cells.
Cd-r and parental MT null cells were exposed to a
multitracer dissolved in the serum-free medium. Afterthe incubation for 2 h, cells were washed twice with
PBS( -) and the radioactivities of metals including Zn,
Fe, Mn, Co, Be, Sc, Cr, Se, Rb, Y, and Zr in the cells
were determined. As shown in Fig. 1, Mn uptake in
Cd-r was as low as about 10% of that in the parental
cells. The uptake of Co in Cd-r was also reduced to14.-----------------------~o Parantal (MT nUll)~

12

Cd-Raalstant (MT nUll)

10
(II

:g

8

'0

6

(f.

4

Q

2
~

~

~

~

~

~

~

~

~

y

~

MetalsFig. 1. Uptake of various elements into the Cd-resistantand parental metallothionein null cells. A multi tracer
was added in the medium of Cd-resistant and parental
metallothionein null cells, and incubated for 2 h. The
uptake of each element was expressed by the % of added
dose.
School of Pharmaceutical Sciences, Kitasato University

124

about 70% of the parental cells. Other metals including Zn and Fe did not show any significant difference
between the two cell lines. Since the accumulation of
Cd in Cd-r cells was also reduced to about 10% of theparental cells, it is suggested that Cd and Mn may
share the similar system for their incorporation into
the cells and that this system may be disrupted in
Cd-r cells.
To further clarify the incorporation system common
for Cd and Mn, we have examined inhibitory effects of
Mn on the uptake rate of 109Cd. Addition of Mn into
the medium efficiently inhibited the uptake of Cd in
the parental cells, while no inhibition of Cd uptake by
Mn was observed in Cd-r cells. These results strongly
suggest that the major part of Cd is incorporated into
the cells via a pathway inhibited by Mn and that thispathway is suppressed in Cd-r cells.
Therefore, we have next examined the accumulationof Mn in the Cd-r and parental cells using 54Mn asa tracer. Mn was incorporated into the cells timedependently, but the rate of uptake is markedly reduced in Cd-r cells. However, this reduction was observed only in the low concentrations of Mn (less than
300 nM), and no difference was observed at concentrations higher than 1 pM, suggesting that there may
exist at least two pathways for Mn to incorporate into
the cells, and that only the high-affinity pathway for
low Mn concentrations may be disrupted in Cd-r cells.
In support of this hypothesis, inhibition experiments
showed that the addition of Cd into the medium efficiently inhibited the uptake of Mn (100 nM) even at
the equimolar concentration. Therefore, it is suggested
that Cd may be transported into the cells via the highaffinity uptake system for Mn.
The mechanism of Cd uptake into cells has not yet
been fully understood. Based on the facts that theionic radius of Cd is very close to that of Ca, and that
Cd is an efficient blocker of Ca channel, it has been
considered that Cd traverses the cell membrane via
Ca channel. However, the present study to have used
the multitracer technique suggested a possibility that ahigh-affinity transportation system of Mn could be themajor pathway for Cd uptake into cells. Further study
is required for the identification of the transporter that
we have characterized here.
References
1) A. E. Michalska et al.: Proc. Natl. Acad . Sci. USA 90 ,8088 (1993).
2) B. A. Masters et al.: Proc. Natl. Acad. Sci. USA 91,
584 (1994).
3) Y. Kondo et al.: Life Sci. 64 , PL145 (1999).

RIKEN Accel. Prog. Rep. 32 (1999)

Influence of Citrate Ions on the Complex Formation of Lanthanide
Ions with Bovine Serum Albumin and Transferrin
K. Endo, N. Sotogaku, K. Matsumoto, R. Hirunuma, S. Enomoto, S. Ambe, and F. Ambe
A number of low molecular-weight ligands, suchas citrate, lactate, hydrogen carbonate, amino acids,
polyphosphates etc. are contained in blood as well as
serum proteins, and these compounds coordinate tometal ions. Several biologically important compoundswith low molecular weight have been shown to form
stable complexes with metal ions, and many of them
have been implicated to play some roles in the absorption of metal ions. For example, lactate appears totake part in specific protein binding, and citrate inprotein and metal binding. 1) It seems that metal ionsare present as coordination chemical species in equilibrium with serum proteins and low molecular weightligands in living body. Although transferrin has been
known to be the predominant transporter for iron ionsin blood, it may be also considered to be importantfor Ln (lanthanide) ions. 2,3) In the present study, theinfluence of citrate on the complex formation of bovine
serum albumin and transferrin with metal ions was examined using the Ln multi tracer.
The Ln multitracer was prepared from gold foil irradiated with a 135 MeV/nucleon N-14 beam at RIKEN
Ring Cyclotron. The preparation of the multitracer
solution was followed by the established procedure. 4 )Fatty acid free bovine serum albumin (BSA) was dissolved in 50 mM HEPES/NaOH (pH 7.4). Apotransferrin was dissolved in 50 mM HEPES/NaOH
and 5 mM NaHC0 3 (pH 7.4) since synergistic C0 32ion is required for metal ion binding to transferrin. Sodium citrate of 0.01 M buffered with 50 mM
HEPES/NaOH was used. The ionic strength was adjusted to 13 mM with NaC!. Each protein solution(0.9 mL) was mixed with the Ln multitracer solution(0.1 mL) containing citrate, the final concentrationof the protein being 1.49 j.LM. For carrier free experiment, the protein and the Ln multitracer solutions
were mixed together and incubated at 37°C for 2 h.
In order to estimate the complex stability constants,
the carriers for the Ln multitracers were added, where
CeCI3, EuCI3·6H20, GdCh·6H 20, Tm203, YbCI 3,
and LU203 were used. The weighted oxides or chlorides were mixed together, and dissolved in 6 M HCl.
After being evaporated into dryness, the Ln carriers
were dissolved in HEPES/NaOH (pH 7.4). This Ln
carrier solution was added to the reaction mixture.
The final concentration of each Ln 3+ (Ln = Ce, Eu,
Gd, Tm, Vb, and Lu) was 50 nM. The concentrationof NaH 2 citrate was 10 mM and the ionic strength of
the solution being adjusted to be 13 mM with NaCl.
The mixture was then incubated at the same condition. After incubation, the mixture was ultrafilteredusing a millipore filter of Molcut II (the molecular cutoff of the filter was 10000 Da). The ,-ray spectra of thefilters were measured by pure Ge detectors and werecompared with those of the standard Ln multi tracer
solution.
The binding percentages of the Ln ions to serum albumin without citrate are shown in Fig. l(a) and thosewith 10 mM sodium citrate in Fig. l(b). Similar results were obtained for the binding affinity of Ln ionsto transferrin. The affinity without carriers was higher
than that with carriers for most of the Ln 3+ studied.
Apparently, the lower affinity observed for the sample with carriers can be explained in terms of the lowered specific activity in the Ln-protein complex. In thepresence of citrate, the binding percentage increased
with increasing atomic number, while in the absenceof citrate such tendency was small. The results clearlyshow that the complex formation of Ln 3+ with albumin
and transferrin are influenced by citrate. The trend
was remarkable for the lighter Ln 3+. It is known thatthe stability constants of Ln ions with simple ligands
such as OH-, C0 32- , and (COOh 2- increase withan increase in the atomic number of the Ln 3+ ions,which is due to the Zeeff /r, i.e., the complex formation enthalpy is more favored for heavier Ln3+. In thepresence of multidentate ligand, the complex formation
is favored further by the chelating effect (entropy effect). In fact, the complex formation of Ln-citrate has
been explained by an increase in the freedom by the
replacement of mono dentate ligands such as H 20 and
OH- with a multidentate citrate ion. S ) However, in thecase of protein being ligand molecule, the formationof metal-protein complex gives unfavorable entropy

50

(b)

10

Co

Eu

Gel

Tm

Vb

Lu

ElelllcotJ- 0 - C.rricrfree

C.

Eu

Gd

Tm

Vb

lu

[ .... eats
_ _ Carrier odded

Fig. 1. Binding percentages of the Ln ions to serum
albumin without citrate (a), and those with 0.01 M
sodium citrate (b). Open squares show the results obtained for the carrier free sample, and filled ones forthe sample with 50 nM carriers. Each datum represents the mean value ± standard deviation obtained by
five measurements.

125

effects involving conformational change of flexible ligand on complexation. In addition, the citrate chelate
is formed through 7-membered ring. The 7-memberedring is more compatible geometrically for Ce ions witha larger ionic radius, although the stability constantof Ln(cith 3 - goes greater for heavier Ln 3 + due to anincrease in Zeeff II. It is also noted that N-atom with astronger ligand field is involved in the ligating atoms ofprotein, which contributes to form more covalent (andstable) bonding than O-atom in carboxyl group in Ln
citrate complex. It is, therefore, concluded that the geometrical compatibility of lighter Ln 3 + ions for forming
citrate chelate will be a dominant factor for explaining
the affinity dependence under the presence of citrateions. These will be possible reasons responsible for thefact that the formation of Ln protein complex for thelighter Ln 3 + was affected more remarkably than theheavier one under a presence of citrate.
Similar values of the binding affinity observed for albumin and transferrin may indicate that both serum
proteins are good transporter for Ln ions in blood

126

if they are present equally in amount. Actually albumin concentration is 3500- 5500 mg in 100 mL ofblood plasma, and transferrin 200- 400 mg. 6 ) These indicate that roughly 11 times larger amount of albumin
is present than transferrin in blood plasma, and thatalbumin is the major transporter for Ln ions.
References
1) J. D. Bell, C. C. Brown, and P. J. Sadler: FEBS Lett.
235, 81 (1988).
2) A. Bezkorovainy: in Biochemistry of Nonheme Iron
(Plunurn Publ., New York, 1980), p. 127.
3) T. Yarnamura et a1.: Nippon Kagaku Kaishi, No . 4,
p. 452 (1988), in Japanese.
4) S. Arnbe, S. Y. Chen, Y. Ohkubo, Y . Kobayashi, H.
Maeda, and M. Yanokura: J. Radioanal. Nuel. Chern.
195, 305 (1995).
5) H. Li, P. J. Sadler, and H. Sun: Eur. J. Biochern. 242,
387 (1996).
6) O. Yamauchi: in Seitai to Kinzoku Ion (Gakkai Shuppan Center, Tokyo, 1991), p. 187, in Japanese.

RIKEN Accel. Prog . Rep. 32 (1999)

Behavior of Various Trace Elements in Zinc Deficient MiceM. Yanaga, T. Ohyama, M. Iwama, T. Yoshida, M. Noguchi,*1
T. Omori,*2 R. Hirunuma, and S. Enomoto
Zinc is one of the most important essential elements
in living organisms and it influences on the activity ofmore than 300 enzymes that participate in a wide variety of metabolic processes, such as, the metabolism
and the synthesis of proteins and nucleic acid etc.
Therefore, it is known that deficiency of this element
leads to skin injury, alopecia, loss of senses, growth
retardation and so on.
In the present work, the multitracer technique wasapplied for investigation of the behavior of trace elements in zinc deficient mice. The technique is thought
to be suitable for this purpose because zinc interacts
with many other trace elements and various kinds ofelements are dealed with simultaneously using thistechnique. Neutron activation analysis is also useful
method for analysing multielement simultaneously inorgans and tissues of living bodies in order to investigate the behavior and roles of Zn. Yanaga et ai. determined six elements in ten organs and tissues of Zn deficient adult mice by means of instrumental neutron activation analysis. 1) They reported that Zn concentrations in organs of Zn deficient mice were not distinctly
lower than those of control mice except for bone andpancreas indicating that Zn had been supplied fromthese organs, mainly bone, to other organs and tissues. They also reported that Co content increased
significantly in all organs and tissues of Zn deficient
mice compared with control mice indicating the partial
substitution of Co with Zn in metal proteins or othermaterials in the Zn deficient mice. It is considered that
there is a possibility that other metal elements substitute with Zn. However, contents of many metal elements are larger than content of Co, then, the slightchange of concentration of the other elements is notreadily detectable in analytical experiment. On the*1*2other hand, tracer experiment may avoid this problem.
In the present tracer experiment, multitracer
solution was prepared as following procedures.
Silver target was irradiated with 12C6+ beam(135 MeV jnucleon) accelerated by RIKEN Ring Cyclotron. The irradiated target was first dissolved in(1 : 1) HN0 3 . Then, Ag was precipitated as AgClwith conc. HCI. After the precipitate was filtered out,
remained multi tracer solution was evaporated under
reduced pressure. The residue was dissolved in physiological saline for administration.
Twenty-one male mice of the ICR strain, 7-week old(32- 34 g), were purchased. These mice were raised ina facility with 12-h light-dark cycle at 24 ± 1°C withcommercial food pellet and tap water ad libitum. After a week, they were divided into two groups. Elevenmice were fed with Zn deficient diet pellets and distilled water, and the other ten with control diet pellets and distilled water. After three weeks of feeding,an appropriate amount of the multitracer physiologicalsaline solution was injected intraperitoneally into eachmouse. One day after injection, about 1 ml of blood
was collected from heart under diethyl ether anesthesia, and then, 10 organs and tissues, such as brain,
liver, kidney, spleen, pancreas, testis, skeletal muscle,bone, small intestine, and skin and hair, were removed.
They were weighed and bottled. The radioactivities ofthe samples were measured with HP Ge detectors. Behaviors of various elements, such as, V, Mn, Co, Zn, Se,
Rb, Sr, Ru, etc., in Zn deficient mice were satisfactory
traced.
References
1) M. Yanaga, M. Iwarna, K. Takiguchi, M. Noguchi, andT. Omori: J. Radioanal. Nucl. Chern. 231,187 (1998).

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

127

RIKEN Accel. Prog. Rep. 32 (1999)

Uptake and Distribution of Trace Elements in Yeast
Saccharomyces cerevisiae
Y. Nose and 1. Yamaguchi
Disposal of the radioactive wastes and nuclear facility accidents are serious problem in worldwide. It has
been known that nuclear facilities produce not only
90Sr and 137 Cs but also various radionuclides. In addition, several radionuclides, including 99mTc, 57 Co and
97Ru, have been used in radiotherapy. Therefore, it isnecessary to construct a recover system of various radionuclides for nuclear pollution countermeasures. To
achieve this aim, metal uptake by microorganisms has
been researched by many investigators for its potential
application to remove the radionuclides from radioactive wastes and environment. 1- 3) Recently, we tested
the uptake of various radionuclides by yeast Saccharomyces cerevisiae, as a model of RI accumulating microbe using a multitracer technique,4,5) and found thatradionuclides of Be, Sc, V, Cr, Mn, Fe, Co, Zn, As, Se,
Sr, Y, Zr, Ru and Rh were taken up by the yeast. 5) In
this paper, we show that tracers of Be, Sc, Mn, Co, Zn ,Se, Sr, Y and Zr were present both on the cell surface
and inside the cell.
S. cerevisiae (JCM7255) was grown in Difco Yeast
Nitrogen Base (Difco) with 0.5% (w/v) glucose at
25°C in a shaker. The cells of 700 ml of cultures(OD 66o = 1.0) were collected, washed twice with a
5 mM 2-(N-morpholino) ethanesulfonic acid (MES)NaOH (pH 5.4), and suspended in 30 ml of the same
buffer. An aliquot of multitracer solution was added,
and the yeast suspension was then incubated for 30 min
at 25°C in a shaker. After incubation, spheroplasts
were prepared as described by Bowser and Novick. 6)
The spheroplasts were homogenized, centrifuged at
1,000,3,000,10,000 and 100, OOOxg to produce precipitate (ppt) 1,2,3 and 4, supernatant (sup) 4 and floating substances, respectively. Each sample was subjected to l'-ray measurement with high-purity Ge detectors.
Figure 1 shows the distribution of 9 tracers in theyeast. All tracers were detected from both digested
cell wall fraction and spheroplasts fraction. In spheroplast, tracers of Sc, Mn, Co , Zn, Se, Sr and Y were

128

Fig. 1. Typical pattern of distribution of 9 tracers in theyeast S. cerevisia e. Each datum represents the relative,-ray activities .

mainly detected from ppt 1 and sup 4 fractions. On theother hand, tracers of Be and Zr were detected fromppt 1, and little or no tracers were detected from ppt 4
and sup 4. These data suggested that all tracers tested
were present both on the cell wall and inside the cells.
Inside cells, tracers of Sc, Mn, Co , Zn, Se, Sr and Y
were present partly as insoluble form possibly bound toorganelles, and those of Be and Zr were mainly present
as insoluble form.
N ext step is to identify the transport systems of tracers from outside to inside the cell.
References
1) L . E . Macaskie and A. C . R. Dean: Biotechnol. Lett. 7,627 (1985).
2) J. S. Watson et al.: Appl. Biochem. Biotechnol. 20,699(1989).
3) G. W. Granham et al.: J. Appl. Phycol. 5 , 307 (1993).
4) S. Ambe et al.: Anal. Sci. 7, Suppl. , p. 317 (1991).
5) Y. Nose et al.: RIKEN Accel. Prog. Rep. 31, 141 (1998).
6) R. Bowser and P. Novick: J. Cell BioI. 12, 1117 (1991).

RIKEN Accel. Prog. Rep. 32 (1999)

Bioaccumulation and Distribution of Sr, Tc and Cs in Soybean
Y. Nose and 1. Yamaguchi
Various radionuclides released from nuclear facilities into the atmosphere can be accumulated in humanbody through food chains. Especially, radioactive Sr,
Tc and Cs have been regarded as the most hazardous
radionuclides, because of its high yields in products ofnuclear facilities and its long half lives. For nuclear
safety assessment, it is necessary to research behaviorsof these 3 radionuclides from soil to crops. In this experiment, we studied the bioaccumulation and distribution of 85Sr, 95mTc and 137Cs from soil to soybean
in short term (0- 480 hr) exposure to a multitracer.
Soybean plants Glycine max were cultured in pots for
2 months. The multitracer containing 85Sr, 95mTc and
137 Cs dissolved in distilled water was applied to thepots. After several hours incubation, the plants were
harvested , dried, and subjected to ,-ray measurementwith high-purity Ge detectors.
Figure 1 shows the bioaccumulation (% dose/g dryweight) of 3 radionuclides from soil to soybeans. The
bioaccumulation reached the maximal levels at around20 hr incubation with a multi tracer , but more than
24 hr incubation (~480 hr) led no significant changes
in the levels.

Figure 2 shows distribution ratios of 3 radionuclides
in fruits , leaves, stems and roots. Radioactive Sr was
detected from all tissues, but its distribution rate wasvaried irrespective of the incubation time. In Tc, relative amounts in roots were decreased from 70 to 10%,
but that in other tissues increased from 25 to 80% dependent on the incubation time. More than 80% of
Cs were distributed into roots, and little amount weredetected from fruits, leaves and stems.
Sr 100

D:Fruits

80

III : Leaves

60~ : Stems

40.

: Roots

20

o.u. .u..w. .u.~. .u.
Tcloo
80

60

40

20
O.u. .u..w..............u.

Csloo
80
60

40

20

o LaI......................
~oos:l~?:l2S~f::!?:l~~~

t~~c~
~

15

Ol)

10

-NM~

Incubation time (hr)

•

] ~

;

,

,

,

,

,

~

0.3

Cs

0.2

Incubation time (hr)Fig. 1. Time dependent bioaccumulation of 85 8r, 95m Tc
and 137 Cs from soil to soybean. Each datum represents
the mean of three trials ± standard deviation.

Fig. 2. Time dependent distribution of 858r, 95mTc and
137 Cs in soybean. Each datum represents the mean ofthree trials.
In this experiment, we show that soybean plants
took up radioactive Sr, Tc and Cs by several hours
exposure to these radionuclides. More than 48 hr incubation resulted in the contamination of edible parts(fruits) by these radionuclides. In addition, the affinity of soybean for Tc was relatively high: about 60% of
Tc administered into soil was taken up, whereas 0.253% of other elements (data not shown) . This property
may be possible to apply to phytoremediation of soil
Tc. That is, soybean leaves accumulate Tc from soil,
and those are harvested and insulated.

129

RIKEN Accel. Prog. Rep. 32 (1999)

Uptake of Rare Earth Elements by Plants
T. Ozaki, S. Enomoto, and Y. Makide*
Under natural conditions, plants absorb a very small
amount of rare earth elements (REEs). The most stable oxidation state of REEs is trivalent, and they aretightly bound to surfaces of rocks and organic substances such as humic acid. Under natural conditions ,plants absorb a very small amount of REEs. However,some plant species, such as Dryopteris erythrosora, absorb a large amount of REEs.l) Considering the low
availability of these elements under natural conditions,some special mechanism, involved in the uptake ofthe elements, is expected to exist in the accumulating
species.
In the present investigation, we have studied the uptake behavior of REEs by several kinds of plant species,
including accumulating and non-accumulating species
for REEs, using the multitracer technique.
Eleven plant species listed in Table 1 were grownon soil, being kept under the controlled climatic conditions (day/night 16/8 h; light intensity 10000 lux;
temperature 25 ± 2°C; and relative humidity 70-80%)
until the shoot length became about 7 cm. Before theuptake experiment , they were kept in the ultrapurified
water for 1 week to reduce the influence of adheringsoil. During this period, the water was changed every
several hours. The pH of the water was adjusted to
5.8 ± 0.1 using 0.01 M of HCI, and the volume was adjusted to 50 ml. After this period, the roots of plants
were kept in a multitracer solution with the same pH
and volume as the preceding treatment. After 1 week,
the roots were washed with 0.1 M HCI to get rid of

the REEs adhered to the surface of roots. Gamma-ray
from both roots and leaves of the plant samples wascounted with a germanium detector.
A multitracer of REEs was produced by the irradiation of Au with a 135 MeV/nucleon 14N ion beam
accelerated by the RIKEN Ring Cyclotron. Additional
details are described in the literatures. 2 ,3)As shown in Fig. l(A) , no appreciable difference
was observed among the plant species in the uptakeof REEs into their roots. For leaves, 9 plant species(a, b, c, d, e, f, g, h , and i) , which do no accumulate REEs 4) showed an anomalously high uptake of Y
among REEs (Fig. l(B)). On the other hand, accumulating species for REEs (j and k) showed no anomaly
with Y. From this, it is suggested that some unknown
mechanisms should exist for the uptake of REEs III
Dryopteris erythrosora and Crytomium fortun ei.

LuYb YGd EuPmCe

LuYbYGdEuPmCe

(a)
(b)
(c)

(d)

(e)

(1)
(g)
(h)
(Q

(j)
(1<)

Table 1. Names of the plant species used for the study.
0.8

Plant species (common name)(a) Luffa cylindrica Roem. (sponge gourd)(b) Antirrhium majus (snapdragon)(c) Pisum sativum (pea)(d) Abelmoschus esculentus Moench (okra)(e) Nicotiana tabaccum (tabacco)(f) Cucumis melD (melon)(g) Amaranthus mangostanus (edible amanranthus)(h) Poa pratensis (kentuchy blue grass)(i) Colysis pothifolia (fern)
G) Cyrtomium fortunei (fern)(k) Dryopteris erythrosora (fern)

Radio Isotope Center, University of Tokyo

130

0.9

1.0

1.1

Ionic radius (A)

0.8

0.9

1.0

1.1

Ionic radius (A)Fig. 1. Uptake of rare earth elements into roots (A) andleaves (B) of plant species. Dotted lines correspond to
the ionic radius of Y.
References
1) T . Ozaki et al.: J. Radioanal. Nucl. Chern. 217, 117(1997).

2) S. Ambe et al.: Anal. Sci. 7, Suppl. , p. 317 (1991).
3) F . Ambe ed.: RIKEN Rev. No. 13 (1996).
4) T. Ozaki: unpublished data.

RIKEN Accel. Prog. Rep . 32 (1999)

Study on the Uptake of Various Elements into Arbuscular
Mycorrhizal Marigold by Multitracer Technique
H. Suzuki,*l H. Kumagai,*l K. Oohashi ,*2 S. Enomoto, and F. Ambe
The roots of most higher plants are colonized by
specific soil fungi to form the arbuscular mycorrhizae
which is an important part of the absorbing root system of the plant. It is well known that the arbuscular
mycorrhizal (AM) colonization enhances the uptake ofphosphorus by plants.!) A few papers have suggested
that AM colonization can also promote the uptake ofother elements. 2) In the present study, we have examined the effect of AM colonization on the uptake ofvarious elements in the symbiotic system of marigold(Tagetes patula L. cv. Bonanza spray) and Glomus
etunicatum (Becker and Gerd) using a multitracer
technique.
Seeds of marigold were sowed in the autoclaved riversand inside a 9 cm pot (240 ml in volume). One
ml of the spore suspension (containing approximately
200 spores) of Glomus etunicatum was pipet ted tothe center of the hole (2 cm in depth) of the growth
medium, prior to sowing, for the mycorrhizal inoculation. A non-mycorrhizal plant was used as control
plant. Plants were grown in an RI-biotron with 16/8 hr
day /night regime, 15000 lux, 65% relative humidity,and 25 0 C. The marigold seedlings were thinned to one
per pot on the 7th day after sowing. The experiment
was carried out at 55% of the water holding capacityof the growth medium.
A multitracer solution was prepared from a Ag foil
which was irradiated with a 135 MeV/nucleon 14N
beam accelerated by RIKEN Ring Cyclotron. The Ag
foil was dissolved in HN0 3, and then the Ag itself was
separated from the multitracer by the form of Agelprecipitate. The filtrate was evaporated to dryness
and dissolved in fertilizer solution. A multitracer solution containing the radionuclides of 7Be, 22Na, 46Sc,
51Cr, 54Mn, 59Fe, 56Co, 65z n , 74 As, 75Se, 83Rb, 85Sr,
88y, 88Z r , and 95 m Tc was administered on the 29th day
after sowing. The plants containing root, shoot , andflower were sampled for analysis on the 7th and 21stdays after the administration of a multitracer solution.
The effect of AM colonization on the uptake of multitracer elements was complex (Fig. 1). On 36th day
after sowing (7 days after multitracer application), theuptake rate (% of dose) of Zn and Tc in the mycorrhizal plant was approximately 2 and 1.5 times large
compared with that in the control plant. On the other
hand, the uptake rate of Sc, Co, and Sr in the mycorrhizal plant was lower than that in the control plant.
On 50th day after sowing (21 days after multitracer
application), the uptake rate of Be, Na, Cr, Fe, Zn,*1*2

Radioisotope Research Center, Chiba University
Faculty of Pharmaceutical Sciences, Chiba University:J?I ::I2J ]~lr:J~ 1 ::12l ]"2J
j

36

36

50

50

36

50

36

50

0 .5

~~
15lE!J 40i2j;...---m
36

50

~
~ 9.~
3

36

50

36

50

20
0

36

50

~15r2J~ 10
0

Rb .**
'O~
45

~

5

20

36

50

36

50

:1HJ
36

50

]2J
36

50

~:12] ::IE] '::~
36

50

Days after sowing

36

50

Days after 'sowing

36

50

Days after sowing

Fig. 1. Uptake rate (% of dose) of various elements inthe mycorrhizal ()() and control plants (0) at two cultivated stages. Each data point in the figure represents
the mean value ± standard deviation obtained fromat least seven preparations (* P < 0.05; ** P < 0.01;** * P < 0.001).
and Tc in the mycorrhizal plant was higher than thatin the control plant, while the rate of Sc, Co, and Rb
in the mycorrhizal plant was lower than that in thecontrol plant. The uptake rate of Mn, As, Se, Y , and
Zr of the mycorrhizal plant was similar to that in thecontrol plant on 36th and 50th days after sowing.
The results show that AM colonization affects theuptake of Be, Na, Sc, Cr, Fe, Co, Zn, Rb, Sr, and Tc
in marigold. The enhancement of uptake of Zn by AMcolonization is probably based on the well-establishedactivity of external mycelium.2) However, the decreasein the uptake of Sc, Co, Rb, and Sr by AM colonization
is not clear. To elucidate this point, further investigation is required.
References
1) K. M. Cooper and P. B. Tinker: New Phytol. 81, 43(1978).
2) H. Marschner and B. Dell: in Management of mycorrhizas in agriculture, horticulture and forestry, edited by
A. D. Robson, L. K. Abbott, and N. Malajczuk (Kluwer
Acad. Publ., Netherlands, 1994), p. 89.

131

RIKEN Accel. Prog. Rep. 32 (1999)

Study on the Distribution of Various Elements in Arbuscular
Mycorrhizal Marigold by Multitracer Technique
H. Suzuki,*l H. Kumagai,*l K. Oohashi,*2 S. Enomoto, and F. Ambe
As shown in the preceding paper, the arbuscular mycorrhizal (AM) colonization increased the uptake of
Be, Na, Cr, Fe, Zn, and Tc in a multitracer solution,
while it inhibited the uptake of Sc, Co, Rb, and Sr.
In this report, we have investigated the effect of AM
colonization on the translocation of various elements.
The experiments were carried out like described in thepreceding paper.
Figure 1 shows the distribution of elements (% ofdose) in the root. On 36th day after sowing (7 days after multitracer application), the distribution of Sc, Co,
and Rb in the root of the mycorrhizal plant was lower
than that of the non-mycorrhizal (control) plant, andthe distribution of Zn in the root of the mycorrhizal
plant was higher than that of the control plant. The
distribution of Be, Na, Cr, Fe, Zn, Sr, and Y in theroot of the mycorrhizal plant was higher than that of
the control plant on 50th day after sowing (21 days after multitracer application). These results show that
AM colonization can promote the accumulation of Be,
Na, Cr, Fe, Zn, Sr, and Y in the root.
The distribution of elements in the shoot is shownin Fig. 2. The distribution of Co, Sr, and Y in the~:]E] ':r2J :~
36

36

50

36

50

36

36

50

36

50

36

50

0-- ::IBJ
36

50

36

50

~'J2J 'JM :~
36

50

36

50

36

50

~ :~ ::1EJ :f936

50

Days after sowing

36

50

Days after sowing

36

50

Days after sowing

Fig. 1. Distribution (% of dose) of various elements in
the root of the mycorrhizal ()() and control plants (0)at two cultivated stages. Each data point in the figure
represents the mean value ± standard deviation (S.D.)
obtained from at least seven preparations (* P < 0.05;** P < 0.01; *** P < 0.001).
*1

.2

132

50

36

50

36

50

36

50

36

50

36

50

36

50

Days aftar sowing

Days after sowing

Days aft a r sowi ng

Fig. 2. Distribution (% of dose) of various elements inthe shoot of the mycorrhizal (x) and control plants (0)at two cultivated stages. Each point is the same as
described in the legend to Fig. 1.

I':r;Il oleJ:~ J?1 ::f)lo~ oLCJ
0.5iL-J
36
50

36

50

36

50

36

50

40FJl 3~ 0.2]Yil lOp:]~ 1~ ':LLJ ':WJ :UiJ
36

50

Days after sowing

36

50

Days after sowing

36

50

Days after sowing

36

50

Days after sowing

50!':J?l :IrlJ J"2ll4fEJ
7~05l1:J
36
50

36~:Yl ,:~ '::r.~llLEJ oleJ 30~~~:~ ::tt!J ]]2!l

,:r:r
::~
tl!:!J 10i!:!J

50

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

Fig. 3. Distribution (% of dose) of various elements inthe flower of the mycorrhizal ()() and control plants(0) at two cultivated stages. Each point is the same as
described in the legend to Fig. 1.
shoot of the mycorrhizal plant was lower than that of
the control plant on 36th and 50th days after sowing,
while the distribution of Zn and Tc in the shoot of themycorrhizal plant was higher than that of the control
plant. The distribution of Se and Rb in the shoot of themycorrhizal plant was lower than that of the control
plant on 50th day after sowing. These results suggestthat AM colonization affects the translocation of Co,
Zn, Se, Rb, Sr, Y, and Tc from the root to the shootin plants.
The distribution pattern of Mn, Co, Se, Rb, Sr, andY in the flower was similar to that in the shoot (Fig. 3).
The distribution of Zn in the flower of the mycorrhizal
plant was higher than that of the control plant, andthe distribution of tracers except Mn and Zn in the
mycorrhizal plant was lower than that in the control
plant on 50th day after sowing.
Our results show that AM colonization affects on
the translocation of Co, Zn, Se, Rb, Sr, Y, and Tc
in marigold. To elucidate the inhibition of translocation of these elements except Zn by AM colonization,
further investigation is required.

RIKEN Accel. Prog. Rep. 32 (1999)

Formation of Metallofullerenes Studied
by the Multitracer Technique
K. Sueki, K. Kikuchi, K. Akiyama,* T. Sawa,* H. Nakahara,
S. Ambe, S. Enomoto, and F. Ambe
Formation of metallofullerenes, especially stable inair and in organic solvents, has been reported only forthe group 2 elements (Ca, Sr and Ba), and for thegroup 3 elements (Sc, Y, and lanthanoids). In thisstudy, formation of metallofullerenes was examined fora large number of elements belonging to the various
groups in the periodic table.
Experiments were performed by use of themultitracer 1} prepared from the 197 Au target bombarded with 12C heavy-ion beam at the Ring Cyclotron. After chemical separation from the target material, the tracer was found to contain 33 kinds of radioisotopes of 28 elements with the number of atomsof each isotope ranging from 2 x 10 10 to 6 X 10 12 .
The amount of each isotope was monitored and determined by ')'-ray measurements with an HPGe detector.
The multitracer and 3 grams of La nitrate were dis. solved in ethanol and adsorbed into a porous carbonrod (1.24 g/cm 3 ). Platinum was not adsorbed into therod. After proper heat treatment of the rod, it wasused as an electrode for fullerene production by thearc discharge method in a vacuum chamber designed
for safe handling of radioactive soot. Sodium and Rb
were lost by the heat treatment at 1200°C. The sootproduced inside the chamber was washed out by CS 2
solvent. No Cr and Os found in the extract. The
fraction of each element in the fullerene-like species
extracted into CS 2 was quantitatively determined by')'-ray spectrometry.
The results are shown in Fig. 1 by solid points•

against the group number of each element in the periodic table. The CS 2 extract was injected into an HPLC
column (5PBB column, 10 mm</> x 250 mm) and eluted
with CS 2 at the flow rate of 1.98 ml/min. The elution was monitored on-line by UV absorption, and theeluted fractions were collected for everyone-minute for')'-ray measurements.
Observed elution curves are given in Fig. 2 (a), (b)and (c). In the last figure is included the elution curvesof the newly discovered metallofullerenes of Zr, Hf and
Nb. The elution peaks were also observed for trivalent
Sc and lanthanoid elements of La, ee, Pm and Gd
and divalent Eu and Yb,2} whereas their curves weresimilar to those for Y and Sr, respectively. The sum of
the radioactivity observed in the column fractions for
Sr, Sc, Y and the lanthanoid, and for Zr, Hf and Nb
is shown in Fig. 1 by open circles. The upper limits of
the yields for Mn and Fe were also estimated from thebackground radioactivity and shown in the figure forcomparison.

Crude/Sooto E1 uote fro ott on/Soot
10 .2

S':

0

!

Retention time I min

•

REE

.~

0::
"tl

y

10·'

'ii

;;:

°J

o HI
Se
Z,o

I

Fig. 2. Elution curves for (a) empty fullerenes, (b) theradioisotopes mostly eluted before C60 (7Be, 58CO, 75Se
and 103Ru), and (c) those eluted at the retention time
expected for the known metallofullerenes.

•

10'"

References
1) S. Ambe, S. Y. Chen, Y. Ohkubo, Y. Kobayashi, M.
Iwamoto, M. Yanokura, and F. Ambe: Chern. Lett.
Group

Fig. 1. Yield of each element extracted into CS 2 solvent
and those of metallofullerenes as a fraction of the respective radioactivity initially present in the soot.
Graduate School of Science, Tokyo Metropolitan University

1991, 149.
2) K. Kikuchi, K. Sueki, K. Akiyama, T. Kodama, H.
Nakahara, 1. Ikemoto, and T. Akasaka: in Fullerenes
4: Recent Advances in the Chemistry and Physics ofFullerenes, edited by K. Kadish and R. S. Ruoff (1997),
p.408.

133

RIKEN Accel. Prog. Rep. 32 (1999)

Application of the Multitracer for Substoichiometric
Determination of Trace Elements: A Proposal
Y. Minai and S. Enomoto
Isotope dilution analysis has been regarded as a
successful application of radioisotopes in analyticalchemistry. I) This technique has been used for determining a single element or component because radioassay was usually achieved by using NaI(TI) gamma
spectrometry or ,B-counting techniques conventionalin tracer studies. Recent development of multitracer
technique allows simultaneous application of various
radiotracers in a particular system. This implies thatisotope dilution analysis, a classical method in radiometric analysis, can revive as a sophisticated methodin multielemental or multicomponent analysis by application of the multitracer detectable by ,-ray spectrometer using Ge semiconductor detector .
One of the difficulties in application of multi tracer
technique to isotope dilution analysis is that the
specific activities of the radioisotopes in the multitracer solution are unknown or diffcult to be determined. Isotope dilution analysis has some variations
like the direct dilution, reverse dilution, and double dilution methods. Direct dilution method is applied for determination of a non-radioactive component. It is necessary to know, in application of thismethod, the specific activity of the radioisotope or labelled compound spikes in the sample solution. Radiochemical separation of radioisotopes in preparation of the multitracer solution needs application ofvarious reagents in glassware under ambient atmosphere. Potentially, contamination takes place fromthe reagents, target material, glasswares, and laboratory air. This implies that monitoring of the levelof non-radioactive components in the multitracer solution is necessary in application of the solution to isotope dilution analysis. However, the non-radioactive
components are sometimes difficult to be determinedbecause of higher detection limit than in radioassay.

134

In substoichiometric analysis developed by Suzuki,2)and independently by Zimakov and Rozhavskii,3) it isunnessary to know the specific activity applied in thesystem. Radioassay after chemical separation is the
only procedure required in this method. It is obvious that substoichiometric method allows us to avoid
ted ius determination of the specific activities of thecomponents. The most important point in substoichiometric analysis is the choice of reagent reactingwith the element or component determined. Principal
requirements for the reagent are as follows:• High stability of the reaction product in solutions,• Moderate or high reaction rate,• Negligible adsorption on surface of vessels, etc.
Use of multitracer is particularly beneficial for determination of the elements or components whose
properties in solutions are quite similar: e.g., lanthanides(III), platinum group elements, Zr-Hf pair,
Nb-Ta pair, and actinides of the same oxidation state.
Due to their similarlity, we can determine those elements or components by applying such a single reagent
that fulfill the requirements mentioned above. As thefirst stage of this research project, simultaneous determination of lanthanides by substoichiometric analysis
using di( ethylhexyl)phosphoric acid will be studied in
the 1999.
References
1) J. Tolgyessy and W. Kyrs : Radioanalytical Chemistry I(Ellis Horwood Ltd., Chichester, 1989).
2) N. Suzuki: Nippon Kagaku Zasshi 80, 370 (1959) , inJapanese.
3) 1. E. Zimakov and G. S. Rozhavskii: Zavodsk. Labs. 24,
922 (1958).

RIKEN Accel. Prog. Rep. 32 (1999)

Intense 18F Positron Beam Source Electro-deposited on Graphite
Y. Itoh, I. Fujiwara, Y. Nagashima, F. Saito, T. Kurihara, N. Suzuki, T. Hyodo , R. Iwata, and A. Goto
An positron source of 18F (half-life 110 min) has
been developed for a polarized slow positron beams.
The radioactive 18F was produced in 2 ml of 180-watertarget via the 180 (p, n) 18 F reaction. A 14 MeV proton
beam from the AVF cyclotron at a current of 1 p,Awas used. The water containing the produced 18F was
diluted and was electro-deposited in a cell on a carbonrod, which serves as a positron source.
The positron emission yield was investigated as functions of applied voltage and deposition time. Graphiterods (diameter 3 or 5 mm) or a glassy carbon rods
(diameter 3 mm) were used for the anode. The voltage was varied from 100 to 180 V. The deposition time
was varied from 5 to 30 min (Fig. 1). The positronemission yield is defined as the product of the electrodeposition efficiency and the fraction of the positrons
emitted from the anode rod surface. It represents thefraction of the positrons available for the slow positronbeam.

lr----.-----r-,---.-----r-,---.-----r, ---,

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rod with 30 min deposition. The result with the 3 mm
graphite rod was 58%. The result with the 3 mmglassy carbon was a little better than that with 3 mm
graphite.
Fraction of the positrons emitted from the electrodesurface was measured with a brass positron annihilation target was visible through a 5 mm gap of a leadslit. The result shows that the fraction of positronemission was about 51% for the 3 and 5 mm graphite,
and about 53% for the 3 mm glassy carbon rods.
Multiplying these values by the corresponding electrodeposition efficiency, the positron yield of the present
system was 44, 30 and 35% for the 5 mm, 3 mm
graphite rod and 3 mm glassy carbon rod, respectively.
For high activity 18F electro-deposition in .the future, an automated electro-deposition and source- supply system designed (Fig. 2). In this system, several
electro-deposition cells are placed on a turn table. The
cells are made of copper gilded with rhodium. They
serve both as cathodes and vessels for the 18F water.
The carbon rod anodes are arranged on the side of avertical rotatable disc, whose center is directly below
the source window of the slow positron beam apparatus. After the cathode cell is filled with the irradiated18F water, it is moved to the position right below thecenter of the vertical disc. The vertical disc is thenlowered for the electro-deposition. After the deposition , the disc is raised to its home position, rotated by
180 degrees, and then raised for the carbon rod to face
the positron incidence window.

-

[8]

I

I

I

10

20

30

Time [min]Fig. 1. Deposition time dependence of the positron emission yield. The results obtained by using graphite rod
3 mm¢, 5 mm¢ and glassy carbon rod 3 mm¢ are indicated by., 0 and 0 , respectively. The deposition was
performed applying 120 V.
To measure the electro-deposition efficiency, the0.511 MeV annihilation I rays from the carbon electrode were counted with a high-purity Ge detector ata fixed distance. The electro-deposition efficiency calculated from the obtained counts was independent of
the applied voltage in the voltage range investigated.
Electro-deposition efficiency increases as a function of
the deposition time, up to 30 min, as expected. The
best result of 83% was obtained for the 5 mm graphite

Fig. 2. Design of an automated electro-deposition andsource supply system. Cells [AJ are placed on turn table. Carbon rods [B] are placed on the side of a verticalrotatable disc. 18F solvent is transferred through thecapillary [C].

1354. Radiation Chemistry and Radiation Biology

RIKEN Accel. Prog. Rep . 32 (1999)

A New 100 ps-Lived Luminescence in Ion IrradiatedInsulator Crystals
K. Kimura, S. Sharma, J. Kaneko, and N. Itoh
Ion irradiation ionizes solid materials at extremely
high density. Except metals, ejected electrons andholes may relax immediately into electron-hole pairs in
one case, and into recombination giving rise to atomic
displacement in another case. The electron-hole pairs,
which are often free excitons, relax by self-tr'a pping,
defect formation, photo-emission, or energy transfer(to defect sites or impurities and to phonon). Ion irradiation adds the density effect to each of all the above
steps. This may induce quite different irradiation effect from that by photon and electron irradiation. It is
our objective to observe these steps directly. Our interest is concentrated in dynamics of the excited states(excitons). So far, the luminescence and its decay havebeen measured for ion-irradiated alkali, alkaline-earth
halides, rare gases, and ion-irradiated oxides using afast decay measurement technique with time resolutionof 100 ps.1) We have found characteristic phenomenaof the high-density excitation by ion irradiation. 1) In
this report, finding of a new extremely-fast-decaying(less than 100 ps) luminescence band is described. We
could observed such band in many insulator crystals
of KBr, KI, RbI, CsCI, CsBr, CsI, NaCI, and A1 20 3 ,but it has not been reported in case of photo- andelectron-irradiation of these crystals. This extremely
short-lived broad band may be ascribed to the collective states of electron-hole pairs. Such finding canevolve not only new track-effect of ions but also newprimary excitation mode in the wide band-gap materials. Now, let us present the result of RbI single crystal
as an example.
A photo- and electron-excited RbI single crystal iswell known to give rise to luminescence bands withpeaks at 320,400, and 540 nm due to three self-trapped
excitons,2) and the weak free exciton band at 213 nm. 3 )The lifetime of the 320 nm-band (named a) is 3 ns;
400 nm-bands are 16 ns (singlet) and 22 f..LS (Ex);
540 nm-bands, 100 ns (singlet) and 11 f..LS (7r).2) By contrast, the time-resolved luminescence spectra of heavy
ion-irradiated RbI revealed a 100 ps-lived broad luminescence band in addition to the a band at 320 nm;
the other bands aforementioned were not recognized in
the range of 20 ns. Figure 1 shows the time-resolved
spectra obtained by Ar-, Kr- and Xe-ion irradiation
at 6 K. The 100 ps-lived luminescence band was too
weak in case of He-ion irradiation to be discerned fromthe noise level of the base line. In addition, the new
100 ps-lived luminescence band showed the large enhancement by excitation-density. The ratio of the luminescence efficiency at time t = 0 (actually, in 20 ps)
was 1 : 7.6 : 53 for Ar : Kr : Xe ions, respectively.

a

2.0

3.0

4.

Time (os)Fig. 1. Wavelength-dependent luminescence decay-curves
Ar-, Kr-, and Xe-ion irradiated RbI at 6 K. a: Ar-ion
irradiation; b: Kr ion; c: Xe ion; d: an expanded plotof c.
This ratio is large far beyond the square of the excitation density ratio, 1 : 1.8 : 2.4.4) This suggests thebindings among many excitons: that is, probably acollective phenomenon like electron-hole plasma in theion track.
References
1) K. Kimura, K. Mochizuki, T. Fujisawa, and M.
Imamura: Phys. Lett. A 78, 108 (1980); K. Kimura andJ. Wada: Phys. Rev. B 48, 15535 (1993); K. Kimura:
Nucl. Instrum. Methods Phys. Res. B 90, 100 (1994);
K. Kimura: Phys. Rev. A 47, 327 (1993); K. Kimura
and W. Hong: Phys. Rev. B 58, 6081 (1998).
2) K. S. Song and R. T. Williams: Self-trapped excitons,edited by M. Cardona (Springer, 1995).
3) H. Nishimura, C. Ohhigashi, and Y. Tanaka: J. Phys.
Soc. Jpn. 43, 157 (1977).
4) K. Kimura, S. Sharma, J. Kaneko, and N. Itoh: to be
published on Nucl. Instrum. Methods Phys. Res. B.

137

RIKEN Accel. Prog. Rep. 32 (1999)

Ion-Induced .Stimulated Emission of 326 nm Band in a-Alumina
S. Sharma, J. Kaneko, and K. Kimura
Numerous spectroscopic studies on the a-alumina
irradiated with electrons, photons, and low and highenergy ions have been carried out in the last decade. 1 ,2)This crystal is a radiation resistive material and also anefficient base material for excitation energy donor for
lasers. Ion irradiated a-alumina shows luminescencebands at 280, 326, 422, 688, and 709 nm. We report
here that out of these bands the 326 nm band shows
stimulated emission.
The luminescence decay was measured using the single ion hitting single photon counting (SISP) technique with a time resolution of 100 ps.3) The projectile ions He 1+, N3+, Ar 8 + , and Kr 13 + accelerated
by the RILAC were used and the ion energies were
2.0 MeV/nucleon. Though the time integrated luminescence spectrum of ion irradiated a-alumina is almost similar to that obtained by electron irradiation,
the decay curves are very different. As mentioned
above, ion irradiated a-alumina shows several luminescence bands though, the decay measurements ofeach luminescence band showed no appreciable intensity from 0 to 25 J-tS except the decay of the 326 nm
band and of a new extremely short-lived band. The decay curve of the 326 nm band was different from thatobtained by electron irradiation. In the case of ion irradiation the decay curve was quite different from asingle exponential, and the initial change was muchlarger than that of an exponential. The decay curves
consisted of a main part (which can be simulated by adouble exponential) and a fast decaying part (Fig. 1a).
The fast decay component is reported in another paper

1.5

3''§ 0.5

Ar

of$

kr

0

References

~

b
kr

1

Ar

0.5
0
0.0

5.0

1. Baryshnikov, E. F. Martynovich, T. A.
Kolensnikova, and L. 1. Shchepina: Sov. Phys. Solid
State 30,868 (1988); E. D. Aluker, V. V. Gavrilov, andS . A. Chernov: Phys. Stat. Sol. (b) 171, 283 (1992).
2) A. Al Ghamdi and P. D. Townsend: Nucl. Instrum.
Methods Phys. Res. B 46, 133 (1990); K. Kimura, W.
Hong, J. Kaneko, and N. Itoh: N ucl. Instrum. Methods
Phys. Res . B 141, 425 (1998) .
3) K. Kimura, K. Mochizuki, T. Fujisawa, and M.
Imamaura: Phys. Lett. A 78, 108 (1980).
4) D . J. Dexter: J. Chern. Phys. 21,836 (1953).
5) Th . Foerster: Ann. Physik 2, 55 (1948).

1) V.

1.5

10.0

Time (ns)Fig.

1. a: Equi-height decay curves of a -aiumina at
330 nm obtained by He-ion irradiation at 170 K, N-ion
at 150 K, and Ar- and Kr-ions at 293 K. b: Ion dependent decay curves of a-alumina measured at 330 nm,

where the intensity was normalized for ion count.
138

in this progress report. As can be seen from the figure, the rate of decay increases with increasing the ion
mass, which is equivalent to excitation density. Curve
fitting gave the following values for the lifetimes 71 and
72 : 1.4 and 8.2 ns (N ions), 1.2 and 4.4 ns (Ar ions),
and 0.76 and 2.6 ns (Kr ions), respectively. Namely thevalues of 71 and 72 decreased with increasing excitation
density. This result implies that the excited states decay by a strong interaction between themselves or withthe other intermediates.
The luminescence efficiency per ion was also foundto enhance with increasing excitation density as shownin Fig. lb. The ratio of the luminescence efficiency at
the time t = 0 is 1 : 3.4 : 44 for N : Ar : Kr ions respectively, while the corresponding ratio of the excitation
density is 1 : 3 : 5.5. The ratio of the luminescence
efficiency is much larger than that of the square of theexcitation density. This super-linear increase as well as
the increase in the decay rate indicates that emission
may be enhanced by the radiative interaction between
the excited states. Since this radiative interaction isstill inadequate to explain the observed luminescence
efficiency ratio, the stimulated emission by the emitted
photons can be considered.
The decay rate was found to increase with decreasing temperature in the case of Ar and Kr ion irradiation, and had a maximum value at 6.7 K at which
the trapped excited states and trapped centers arefrozen. Therefore, not only the luminescence fromthe recombination of the trapped centers but also theradiative contact interaction due to the diffusion of
the excited states are ruled out. Hence , the interaction must be a distant interaction: i.e., the interaction being effective without contact collisions, similar
to exchange 4 ) and/or dipolar interaction,5) and stimulated emission by the emitted photons. The excitation
density-enhanced stimulated emission through a distant interaction is the first finding and is contrary to
the usual results of scintillation research.

RIKEN Accel. Prog. Rep . 32 (1999)

Luminescence Spectra: and Decay Curves of Ion Irradiated"CVD Diamond
J. Kaneko and K. Kimura

Cathode luminescence is a standard method forcharacterization of diamond crystals, because it is possible to extract some information about band-gap energy, centers of impurities and vacancies. A high purity
Chemical Vapor Deposition (CVD) diamond polycrystal was irradiated by several kinds of ions, i.e., He,
Ar and Kr from the RIKEN Linear Accelerator. The
luminescence from the CVD diamond crystal irradiated by ions was measured at room temperature andat around 77 K. Moreover, a time-resolved spectrum
was measured by using Single Ion hitting and Single
Photon counting (SISP) system!) whose time resolution was better than 100 ps.
A high purity CVD diamond polycrystal which was
produced by a plasma assisted chemical vapor deposition technique was used in this experiment. The CVD
diamond crystal was estimated to contain fewer impurities than a type IIa single diamond crystal produced
by a High Temperature and High Pressure (HTHP)
method. Each grain of the CVD diamond crystal had
size of several /-Lm. A full width at half maximum of
Raman peak of the CVD diamond crystal was the sameas that of a type Ib single diamond crystal producedby the HTHP method; besides, any carbide component was not observed in a Raman spectrum of the
CVD diamond crystal.
In general, a luminescence band called as a band
'A' is predominant in cathode luminescence spectra of
diamond crystals. The CVD diamond crystal had a luminescence center of the band 'A' at 350 nm at 80 K.
On the other hand, a high purity type IIa single diamond crystal had the luminescence center of the band
'A' at 545 nm at the same temperature. 2 ) The originof the band 'A' in the cathode luminescence spectrumof diamond is not clear at present. Therefore, it isdifficult even to make a qualitative understanding on
the difference of the band 'A' of these two diamond
crystals. However, each grain size of the CVD diamond was bigger enough than an effective volume indiamond that suffered an influence of an ion bombardment, i.e., ionization. Therefore, it probably caused bya difference in quality of single crystals, not caused bya difference between a single crystal and a polycrystal,i.e., existence of grain boundaries.
Figure 1 shows a time-resolved spectrum of the CVD
diamond bombarded by Ar 8 + ions whose energy was
2.0 MeV at 74 K. Usually, luminescence in the band
'A' has a long decay constant in the order of ms.
This time-resolved spectrum was measured in the time

range of 20 ns. Hence, the band 'A' luminescence was
not observable in this spectrum. A peak located ataround 235 nm was caused by the recombination of
free-excitons. This free-excition recombination luminescence reflects band-gap energy of diamond: thus,
it is considered as an index of diamond crystal perfection. Figure 2 shows a decay curve of free-exciton
recombination luminescence. It consisted of two decay constants of 0.32 and 4.8 ns. The time resolutionof the SISP measurement system was about 100 ps.
Therefore, there was a possibility that the fast decay
constant of 0.32 ns slightly deteriorated. The slower
component with decay time of 4.8 ns had the same luminescence structure to continue up to 400 nm as seenin Fig. 1.

Fig. 1. Time-resolved spectrum of the CVD diamond
crystal irradiated by Ar 8 + at 74 K.

300
CVD Diamond
Temperature: 80K

r--I

:::J

ro

200

8

'---'

-C
Q)

t

Ion: At , 2.0MeVIn

100

>=
0
0

23456
Time [ns]Fig. 2. Decay curve at the 240 nm line from the CVD
diamond irradiated by Ar 8 + ions at 74 K.

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).

139

RIKEN Accel. Prog. Rep. 32 (1999)

Intramolecular Electron Transfer in Cytochrome c Observedby the Muon Spin Relaxation Method
K. Nagamine, F. L. Pratt, S. Ohira, 1. Watanabe, K. Ishida, S. N. Nakamura, and T. Matsuzaki
Electron transfer in macro-molecules such as protein
is the most important mechanism for various biologicalphenomena. A number of experimental investigations
have been carried out to explore the electron transfer phenomena in proteins and related chemical compounds. However, almost all the existing informations
on the electron transfer has been obtained by essentially macroscopic methods, which measure the evolution of the complete electron transfer from donor toacceptor.
Among various types of proteins, cytochrome c attracts much attention, since it plays an essential rolee.g. in the respiratory electron transport chain in mitochondria; it holds a position next to the final processof the cycle and transfers electrons to the surroundingoxidase complex.
In order to obtain microscopic information on electron transfer in the macro-molecule, the muon spin
relaxation (J.LSR) method, offers a great potential. Depending upon the nature of the molecule, the electron
picked-up by the J.L+ during the slowing-down process
in the molecule can take characteristic behaviours including a localization to form a radical state, and/or
a linear motion along the molecular chain, etc. Thesebehaviours can most sensitively be detected by measuring the spin relaxation process of the J.L+ using the
J.LSR method.
Experiments on the J.L+ relaxation in cytochrome chave been conducted by using an intense pulsed beam
(70 ns pulses at 50 Hz repetition rate) of 4 MeV J.L+ at
the RIKEN -RAL.
At each of the measurement temperatures, theJ.L+ relaxation function which corresponds to a timedependent change of the J.L+ polarization, was foundto have an external field dependence (see Fig. 1). The

observed relaxation functions G(t) were fitted with therelaxation function proposed by Risch and Kehr andthe longitudinal relaxation parameter r obtained atvarious temperatures is seen to decreases monotonically with increasing B ext (Fig. 2). On closer inspection of the Bcxt dependence of r, there seems to be
two components, (1) a region of weak-field dependence
region (lower field) and (2) a (Bexd dependence region(higher field). The latter region exhibits the characteristic J.L+ spin relaxation behaviour due to a linear motion of a paramagnetic electron. The criticalfield (hereafter, we refer to this as the cutoff field)
where the second region becomes significant over the
first region has a significant temperature dependence;the cutoff field is seen to reduce with decreasing temperature (Fig. 3) . It can be seen that the temperature dependence of the cutoff field can be represented
by the sum of two activated components of the form
exp( - Ea/kT) , where Ea is an activation energy; one
with an activation energy of 150 me V (dominant above
200 K) and the other with an activation energy of lessthan 2 meV (dominant below 200 K). A naive picture based upon the previous J.L+SR studies on highmolecular weight conducting polymers would suggest
an increase in the effective dimensionality of the diffusion rate. In the context of protein such as cytochrome

N

g

30

300K

250K

275K

a>

~

10

N

30

g
Gl

2S~------~~------~

SKr-------~

110K

280 K

~
c

10

~

3

.g

..

'0;

50GB

CI:

:.::
CI:

N

g

30

a>

'@

10

c

.Q
~

~

3

0;

CI:

o 2

4

6

8

Tlme (1'-5)

10

0

2

4

6

e 10

Tlme (1'-5)

0

2

4

6

8

10

TIme u,.s)Fig. 1. Typical p,+ spin relaxation time spectra in cytochrome c at 5, 110 and 280 K under externallongitudinal fields of 0, 50 and 500 G (above) . For finite fields
the curves show best fits using the R-K function.

140

:.::
a:

30

100 300 1000 3000

MagnetiC Field (G)30

100 300 1000 3000

Magnetic Field (G)30

100 300 1000 3000

MagneUc Field (G)Fig. 2. The R-K relaxation parameter r versus externallongitudinal magnetic field for the p, + in cytochrome c
at various temperatures.

3x10

10

12

12

.a--<>-

.!EO
3x10

11

3000

~

1000

"=

~

rrY
300

EA <2meV

0.004

0.006

O.OOB

0.01

Fig. 3. The upper plot shows the temperature dependenceof the inter-site diffusion rate of electron derived fromB- 1 dependent part of r and the lower plot shows thecutoff field against inverse temperature.

c with coils and folds in its structure, the 'inter-chain'diffusion might perhaps be interpreted as 'inter-loop'
jumps, which could well be strongly activated by theincreased thermal displacement of the polymer occurring above the glass transition .
The most important unknown factors in the present
J.L+SR studies are the distribution oflocations of the J.L+
bonding-sites with corresponding uncertainty in theelectronic structure of the J.L+ and the site from where
the electron starts its liner motion. For this purpose,muon spin RF resonance as well as level crossing reasonance will be most helpful. These experiments are
now in progress.
Although, as mentioned above, there are still some
unknown factors at this stage concerning the detailed
nature of the probe state, it is clear that the electrontransfer process through a microscopic section of cytochrome c was directly detected in the present experiment. The J.L+SR measurement, where high efficiencyof the measurements should be emphasized, is easily
able to be extended to cytochrome c in various chemical and biological environments. Most importantly,
because of original high energy nature of the probe,
this method can be applied to a protein in vivo.

141

RIKEN Accel. Prog . Rep. 32 (1999)

Trans~ocation Behavior of Sr, Rb, and Zn in Soybeant
S. Gouthu, T. Arie, and 1. Yamaguchi
Monitoring the uptake and translocation behaviorof radio nuclides in plants is important to know how
nuclides with contrasting behavior enter through theplant system and ultimately reach edible parts. The
ready mobility coupled with the demand by the growing parts of the plant can carry some nuclides to edible
parts in high quantities. In this study we monitoredtranslocation of strontium (85 Sr), manganese (83 Rb.),
and zinc (65 Zn) in soybean plant with plant growth.
Soybean (Glycine max Merr.) seeds were germinated on sterile sand supplemented with nutrient solution made from Gamborg's B5 medium salt mixture (Wako Pure Chern. Indust., Ltd.). Fresh nutrient solution was added every 4 days until the seedlings
were 2 weeks old. Then the plants were removed fromthe sand and were kept in aerated deionized water for
1 week to facilitate rapid absorption of radionuclides
later. From deionized water plants were transferred tonutrient solution in 300 ml flasks. Each plant was supplied equal amount of multitracer solution. The plants
were maintained in the growth chamber at 24°C, 75%
humidity, and 9000 lux light intensity with a 16 h photoperiod for 10 days. The volume of nutrient solution
in the flasks was maintained with deionized water. After 10 days the plants were removed from the multitracer solution and were transplanted to soil (Kureha
Eng. Co. Ltd., Kureha Chern. Indust. Co., Ltd.). Soybean developmental stages at the time of sampling
were described following the scheme of Fehr et al. l )V 4, V5, and V7 indicate the plant vegetative stages
with 4, 5 and 7 nodes on the main stem respectively.
R1 indicates the starting of flowering; R3, emergenceof pod; R5, beans just beginning to develop; and R6,
pod containing full size green beans. Thirty-one day
old plants at V 4 stage, recovered from multitracer andtransplanted to soil, as mentioned above , were allowed
one week for acclimatization. From V5 stage, plants
were sampled six times (three replicates) at 6 day intervals up to the fruiting stage (R6). Ten days wereallowed between R5 and final sampling at R6 stage
to complete seedfill in the pods. The sampled plants
were separated into root, stem, leaf, flower, pod, andseed and were dried at 50°C for 4 days. Translocationof absorbed nuclides within the plant was assessed bymeasuring the activity of the nuclides in the samples
harvested at different growth stages. Activity measurements were performed using hyper-pure Ge-detectors.
The amount of each nuclide was expressed as percentage of the total nuclide absorbed by the whole plant.
Figure 1 shows the partitioning of Sr, Zn, and Rb
among different organs of soybean with plant matuCondensed from the article submitted to Environ. Toxico!.
Chern.

142

Sr

100
80

c::

•

0

Seed

II PodEI Flower

.~ 60

:s

~ LeafStem~ Root

CI)

0

6 40
~

20
0
V5 V7 Rl R3 R5 R6
Rb

Growth stage

100
c::

80

0

' ':;)

E 60
'5

B40

~

20
0
V5 V7 Rl R3 R5 R6
Growth stage
Zn

100
c::

80

.9

~ 60

B40

~

20
0
V5 V7 Rl R3 R5 R6
Growth stage

Fig. 1. Distribution of total accumulated Sr, Rb, and Zn insoybean tissues at different growth stages. Distribution
is expressed as percentage of plant accumulated nuclide
partitioned in root, stem, leaf, flower, pod , and seed.
Each value is the mean of three replicates.

ration. At 1st sampling (V5 stage) more than 95%
of the absorbed Sr was already translocated from theroot. Stem and leaves were the primary sinks until R3 stage. During this vegetative period the leaf
biomass was increasing and there was clear movementof Sr from stem to developing leaves. As flowering progressed (R3 to R6), most of the Sr was remobilized into
the inflorescence with leaf and stem activity decreasing
concomitantly. At the time of the final sampling (R6),
the Sr partitioning in the inflorescence was as much as70%, with only 10% moving into the pod and none intoseed. Zinc showed the same type of trend throughout

the vegetative stage, but once flowers and fruits wereformed about 33% was translocated into the fruits, ofwhich 8% was in the pod and 25% in the seed. Rb
showed a similar trend of partitioning, but the content
of Rb in the root fluctuated with plant growth stage.
At R6 stage about 43% was partitioned into the fruitwith 31 % in the seed and the rest in the pod.
From Fig. 1, mobilization of Sr, Rb, and Zn fromthe older parts to new growth with plant maturity was
clear. The initial increase observed in the leaves wasdue to the movement of these nuclides from stem tonewly formed and rapidly growing leaves. As the plant
entered reproductive growth (R3 to R6) there wasrelatively little increase in the leaf biomass. Substantial amounts of these nuclides were then lost from theleaves and transported into flower and fruit parts. Thissuggests that these elements are mobile and physiologically important in the actively growing plant tissues.
Pod and seed acted as a sink for 40% of the Rb and30% of the Zn with most activity concentrating in theseed, whereas Sr was not translocated to fruits in significant quantities.
References
1) W. R. Fehr, E. Caviness, D. T. Burmood, and J. S.
Pennington: Crop Sci. 11, 929 (1971).

143

RIKEN Accel. Prog. Rep. 32 (1999)

LET Dependence of Survival in Arabidopsis thaliana Irradiatedwith Accelerated Heavy Ions
N. Shikazono, A. Tanaka, Y. Hase, H. Watanabe, S. Tano,* N. Fukunishi, and S. Kitayama
The biological effects of heavy charged particles,
measured by the relative biological effectiveness (RBE)on lethality as a function of linear energy transfer (LET), have been extensively studied in bacteria,
yeast, and mammalian cells. In these unicellular systems, it was observed that the RBE on reproductive
death was found to peak around 100 keY / 11m.!)
The effects of heavy ions on multicellular organisms
are still not fully understood. The A rabidopsis thaliana(1.) Heynh. is a particularly suitable multicellular organism for studying the effects of heavy ions and otherkinds of radiation because its seeds and plants are
small, it produces a large number of seeds, and because
its life cycle is short.2) We had investigated the effectsof heavy ions on the survival of A rabidopsis using various kinds of ions with LETs of 17-549 keY / 11m, andreported that the highest RBE value was obtained by
Ar ion irradiation (LET 252 keY /l1m. 3 ) More recently,
using Ne and Ar ions at the RIKEN Ring Cyclotron,
we elucidated that RBE value of survival seems to havea peak at LET over 300 ke V / 11m. To further investigate the dependence of RBE on LET in A rabidopsis,
we used carbon (C) ions at various LETs.
For irradiation, the dry seeds of A rabidopsis thaliana
ecotype Columbia were carefully sandwiched as a single
layer between kapton films (7.5 11m thickness). Seeds
were exposed to the C ions accelerated by RIKEN Ring
Cyclotron or by AVF Cyclotron at J AERI (Takasaki).
The LETs for C ions (72, 113, 152, 214 keY / 11m) werevaried by placing absorbers in front of the irradiationsite. The plants were grown at 23°C under continuous
light (40 I1E/m 2 /s). One month after sowing, plants
with expanded rosette leaves were scored as survivors.
RBE value was estimated by comparing D37 for electrons with that for C ions.
The survival curves for C ions with LET 72, 113,
152 and 214 keY / 11m are shown in Fig. 1. C ions with
LETs of 214 keY /l1m had the smallest shoulder andthe highest RBE. The RBE increased with LET. In
Fig. 2, RBEs of C ions are plotted as a function of LET,
together with those of Ne and Ar ions which were measured previously. The RBE for lethality of A rabidopsis
seems to have a peak at LET over 300 ke V / 11m.
Recently, it was reported that the peak of RBE
on the interphase death compared to the reproductive
death is shifted to a larger LET (around 230 keY / 11m)
in mammalian cells. 4 ) The difference in LETs of thepeak of RBE between unicellular systems and A rabidopsis may be explained by assuming that the
JAERI, Takasaki Radiation Chemistry Research Establishment

144

~

0

>
>

LET72
LET113
LET152
LET214

•

a

~

::J
(/)

•

0.1

0.01

o

100

200

300

400

500

600

Dose(Gy)

Fig. 1. Effects of C ion beams with different LETs on
survival. 0: LET 72 keV//-Lm,.: LET 113 keV//-Lm, 0:
LET 152 keY / /-Lm, .: LET 214 keY / /-Lm.

15

LI.J

co
0::

10

5

o

c

•

Ne

a

Ar

1000

100

LET(keV / ~ m)

Fig. 2. RBE for lethality with C(o), Ne(.) and Ar(o) ionsas a function of LET.

interphase death rather than the reproductive deathof cells have major influence on lethality of Arabidopsis plants. Alternatively, different repair mechanism(s)may be the main cause of the different LETs to givethe peak of RBE on survival in unicellular systems andin A rabidopsis.
To verify the latter possibility, RBE values on chromosome aberrations are now being investiagted byvarying the LETs.
References
1) G . Kraft: Nucl. Sci. Appl. 3, 1 (1987).
2) U. Bork et al.: Adv. Space Res. 9, 117 (1989).
3) A. Tanaka et al.: lnt. J. Radiat. BioI. 72, 121 (1997).
4) H. Sasaki et al.: Radiat. Res. 148, 449 (1997).

RIKEN Accel. Prog. Rep. 32 (1999)

Effective Plant-Mutation Method Using
Heavy-Ion Beams (III)T. Abe, S. Sekido, L Yamaguchi, and S. YoshidaIn the previous paperl) we have reported that thefertilization cycle of tobacco is quite sensitive to theirradiation of heavy-ion beams. However, it is difficult
to use this special stage for the plants that have several
seeds per flower . In this paper we report the effect ofheavy-ion beams on imbibition seeds, and on selectionof chlorophyll mutants in M2 progeny.
The rice seeds (Oryza sativa cv. koshihikari) were
soaked for 3 days in water with 0.8% agar at 30 cc
under dark. The imbibition seeds were irradiated by
Ne-ion beams (135 MeV lu) within a dose range of 5
to 100 Gy. Linear energy transfer of the Ne ion was
63.4 ke V I j.lm. After the irradiation, seedlings weretransplanted into soil in pots, and grown in a greenhouse at 20-26 cC. One month after the irradiation,
numbers of the survival plants and morphologically abnormal plants were counted. M2 seeds from selfed Ml
strains were harvested approximately four months after the irradiation. M2 seeds were sown on seed beds,
and grown in a greenhouse. After 3-weeks, the numberof chlorophyll mutants was recorded.
High irradiation dose caused a decrease in the survival rate and an increase in the frequency of morphologically abnormal plants (Fig. 1). The morphologically abnormal plants had a retarded growth, adwarfism, or white stripes or split shape of leaves
in the M 1 progeny. There were 8 sterile plants in
36 typical abnormal plants. Thirty-seven M2 progeny
out of 730 treated-strains were segregated into green
and chlorophyll mutants as the albino or the stripedleave phenotypes (Table 1). The heigher frequencies of chlorophyll mutants (CM) 11.6 and 6.12%
are obtained by the irradiation of Ml strains with
20 and 10 Gy, respectively, whereas the frequency
was 2.18% with ,-ray irradiation of dry seeds. 2) Although mutants with the yellowish green or pale green
leaves were more frequent by ,-rays than by ionbeams, the albino phenotypes were more frequent by
ion-beams than by ,-rays. Above work has shownthat ion-beams irradiation on imbibition seeds can

100ur~~------------------~

o

so

25

75

100

125

Dose (gray)Fig. 1. Effects of imbibition seeds with Ne-ion beams on
the suvival rate (0) and on the frequency of morphologically abnormal M1-plants (.).
Table 1. Frequency of chlorophyll mutants (eM) inducedby ion-beam treatment.
No. of ~ strains

Dose

No. of(Gy)

M. strains

Albino5

225

10

total No. ofFrequency ofWhite stripes

CM

CM(%)

2

0

2

0.89

196

II

1

12

6.12

20

181

21

0

21

11.60

50

115

0

2

2

1.74

100

13

0

0

0

0

Total

730

34

3

37

5.07

give a higher mutation rate and a wider range in thetype of mutants compared to the case of ,-ray irradiation.
References
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) H. Nakai et al.: Breed . Sci. 44, Suppl. 1, p. 290 (1994).

145

RIKEN Accel. Prog. Rep . 32 (1999)

Isolation of the Flower-Color Changing Mutant Using
Heavy-Ion Beam Irradiation
K. Suzuki, T. Abe, Y. Katsumoto,* Y. Fukui,* S. Yoshida, and T. Kusumi*
Flower color is the most important characteristics offloricultural crops. Isolation of mutants with a highfrequency is a powerful tool to generate new kind offlower colors. The newly identified mutations could
be later transported to other plants by a traditional
breeding system. Petunia altiplana, one of the parentof P. hybrida, shows a dominant purple flower color.
It is, however, difficult to isolate the plants which contain homozygous recessive mutant alleles, because of
the self-incompatibility found in many native Petunia
species.
Using the ovaries with pistil excised after pollination, we first found that the expected time for fertilization following pollination in P. altiplana was about
36 to 48 h. We tried to use ethyl methanesulfonate(EMS), a common and quite efficient chemical mutagen in plants. The P. altiplana pollinated ovaries
were incubated on a 10% EMS solution. However, nomutant phenotype was observed among the flowering
plants derived from EMS mutagenized seeds. As analternative, we used a method involving the heavy-ion
beam irradiation on fertilized egg cells for the isolationof flower color mutants in P. altiplana. After 44 h ofpollination, ovaries were irradiated with 5 to 200 Gyof the 20Ne heavy-ion beam at 135 MeV lu. The linear
energy transfer (LET) of the Ne ion was adjusted to
be 63.0 ke V I j.lm. In the irradiation with a dose above
100 Gy, ovaries to develop for mature fruits were notobserved. In contrast, many mature seeds were derived from the ovaries irradiated with a dose less than
50 Gy. The germination rate of the mutagenized seeds
decreased with the intensity of the irradiation (Fig. 1).
Out of the 102 M1 plants, derived from the 5 Grayirradiated ovaries and cultivated in a green house, we
isolated one flower-color changing mutant called pnel.
The pnel flower presented a whitish pink color withpink veins in its corolla tube. High performance liquid
chromatography (HPLC) analysis of the anthocyanins
extracted from limbs and corolla tubes indicated a verysignificant reduction in the amount of malvidin 3-(pcoumaroyl)-rutinoside-5-glucoside, final product in theanthocyanin pathway, in the pnel mutant comparedwith the wild-type (Fig. 2). The pnel mutation has adominant character as determined from the result ofInstitute for Fundamental Research, Suntory Ltd .

146

100~----------------------------------1

Petunia altlplanal

44 hours after pollination
135 MeV/u 2°Ne

80

i60
c
o

~

.540
E

~

20

200

150
100
50
Heavy Ion Ne beam Irradiation (Gray)

Fig. 1. Germination rate from the seeds derived from
irradiated ovules of P. altiplana.
Delphinidin
600<='500i.~... ""().(lie

0MalvidinPetunidin

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

011

011

H

011

Ole-o

().(l~....c""

oc~

Ole-o

..--

100

...WT

pne1
limb

pM1
lube

WT

pne1
limb

().(lJo.O.Aho-Cou

pne1
lube

WT

-

pne1
limb

pne1
lube

Fig. 2. Accumulation of anthocyanidins in wild-type andpnel mutant. The structures of anthocyanin which derive from each anthocyanidin and mainly accumulate in
P. altiplana flower are shown.

backcrossing pnel with wild-type P. altiplana. Previously, we identified some vein-type mutants, similar topnel among natural population. The mutations presented in these plants were also dominants. The frequency of flower-color changing mutants following theirradiation of 5 Gy 20Ne heavy-ion beam was about
1% in our petunia system, indicating an increase in themutation rate about 100 times compared with natural
conditions in petunia (0.01 %).
References
1) T. Abe et al.: RIKEN Accel. Prog. Rep. 31, 148 (1998).

RIKEN Accel. Prog. Rep. 32 (1999).

Produciton of Non-Organogenic and Loosely-Attached Callus In
Leaf Disk Culture of Haploid Nicotiana plumbaginifolia
by 14N Ion Beam Irradiation
H. Iwai, T. Abe, S. Yoshida, H. Kamada,* and S. Satoh*
Leaf disks of the haploid and diploid Nicotiana
plumbaginifolia were irradiated by 14 N heavy-ion
beam, and then they were cultured in shoot-inducing
medium in order to produce mutants for the elucidation of the functions of the cell wall in plant morphogenesis. Haploid plants are desirable for making mutants in tissue culture because recessive mutations appear directly in the phenotype in such plants.
All samples were irradiated with a 135 MeV /u 14N
ion beam accelerated by the RIKEN Ring Cyclotron.
Linear energy transfer (LET) of the 14N ion corresponded to 34 ke V / j..lm. Leaves placed in plastic petri
dishes aseptically were exposed to the 14N ion beam
for specific periods of time, corresponding to doses
ranging from 1.25 to 40 Gy. Then the leaves (including veins) were immediately cut into pieces (approximately 6 x 6 mm). The leaf disks were cultured on the
Murashige and Skoog's agar media containing 1 mg/l
benzyl adenine for shoot induction under a continuous
light conditions for three months. The normal callus
formed hard cell-clusters with multiple shoots, but apaste-like callus with weak intercellular attachments
was found in the irradiated culture.
We confirmed the characteristics of the paste-likeloosely-attached callus by touching it with tweezers.
The survival rate was defined as the percentage of theleaf disks that avoided entire browning. The frequency
of cell proliferation was defined as the p ercentage of theleaf disks on which callus and/or adventitious shoot areformed.
Normal leaf disks began to form the callus with multiple shoots and adventitious shoot after about tendays of culture. The frequency of cell proliferation decreased in parallel to increasing dose in both haploidand diploid leaf disks. The frequency of cell proliferation in diploid was higher than that in haploid, as
shown in Fig. 1. A decrease in survival rate (up to80%) was observed at 40 Gy in the haploid plants;
there was no change in the diploid plants. The frequency of formation of non-organogenic and looselyattached callus in the culture of haploid leaf disks wasmuch higher than that of the diploid disks (Fig . 2).
The highest frequency was obtained at 5 Gy of irradiation in the cultures of both haploid (11.8%) anddiploid (4.1 %) leaf disks. The cells stimulated by theheavy-ion beam were observed with a scanning electron microscope to be loosely attached to each other,resulting in a random morphology of cell clusters.

-.- -.----~----------~

100""'..........

1

100

2n

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

~ 80

80

n

c:

.2

~ 60

~

60

=40
Q)

40

I
I

:

l
Q)

ea.

~
«i
>

()

.~

'0

::s
20

~ 20
c:

C/)

Q)

::s

0~

~

0

~

o

__

~

__

~~

10

__

15

~

20

__

L_~

2S

__

30

~

__

3S

~

0

40

Dose (Gy)Fig. 1. Effects of the dose of 14N-ion beam on theleaf disks of haploid (n) and diploid (2n) Nicotiana
plumbaginifolia. Results are expressed by the percentages of non-browning leaf disks (survival rate) and thatof callus- and/or shoot-forming leaf disks (frequency ofcell proliferation).
o
'2:

~

12,--y----r---,----.----,----,-------,-----.----.,--,

o

c:

co
~

10

C:

g- 8

'O~
c:rJl

g~

~~

6

..... '0

.Q~
~g

4

-:=
~ 2

a

~Q5

c:rJl

~

g 0

,~~

.... 'u~0----5L---L---~--~---L--~--~----~
10

15

20

25

30

35

40

Dose (Gy)Fig. 2. Effects of the dose of 14N_ion beam on the
production of non-organogenic and loosely-attachedcallus. Results are expressed by the as percentageof the leaf disks on which the non-organogenic andloosely-attached callus are formed.

On the other hand, the normal cells formed a tight callus with multiple shoots. These results show that the
14N ion beam irradiation is a powerful tool for obtaining mutants at a high occurrence rate if the haploid
plants are used.

Institute of Biological Sciences, University of Tsukuba

147

RIKEN Accel. Prog, Rep , 32 (1999)

Biological Effects of Heavy-Ion Beam on Budding Yeast Cells
M. Yoshimasu, T . Abe, S. Yoshida, T. Inoue, * F. Ling, and T. Shibata
Mutants are required for identifying novel genes andtheir roles. Many mutants have been isolated frombudding yeast Saccharomycese cerevisiae, which is regarded as a model of eukaryotes. Generally, this process starts by treating yeast cells with mutagens suchas ethylmethansulfonate (EMS), nitrosoguanidine, orultraviolet (UV) light. For the isolation of different
mutations, the kind of mutagen is an important factor. Recent studies showed that the exposure of cells
to the heavy-ion beam introduced DNA double-strand
breaks in diploid yeast cells or in a human tumor cellline. 1 ,2) Double-strand breaks are known to be repairedby error-free recombinational repair or by error-prone(i.e., mutable) end-joining.
First, we examined the relative biological effects on
the survival of yeast cells (IL166-6b , a leu2, ura3, trpl[p+J) .3) The cells, grown in glycerol medium at 30°C
for 3 days, were spread on an 1% agar containing plate
without the required amino acids for its growth. Thesecells were then irradiated by N-ion beam within therange of dose 20 to 1000 Gy or by Ne-ion beam within
the range of 5 to 200 Gy using RIKEN Ring Cyclotron.
The linear energy transfer (LET) of the Nand N e ions,:ere adjusted to be 28.5 and 63.0 keY / /-Lm, respectIvely. After the irradiation, cells were suspended insterilized water , and then spread on glucose plates toform about 300 colonies per plate at 30°C for 4 days.
As shown in Fig. 1, when cells were irradiated by
the N ion, viable cells decreased exponentially in therange from 0 to 250 Gy. In the case of Ne-ion irradiation, we observed exponential decrease in the viability in the range from 0 to 50 Gy. This result
suggests that the yeast cells were differently susceptible to the two types of heavy ion used in this study.
N ext, we compared the effects of irradiation of N e
ion with those of EMS treatment or UV irradiation
on .the induction of temperature sensitive (TS) mutatIOns (Table 1). After the treatments with various
mutagens, cells at the same mortality (31.8 ± 1.8%)
were selected and spread on glucose plates. After incubation at 30° C for 4 days, colonies on each plate

Table 1. Induction of TS mutations by various mutagens.

~
B
~

>
.;:
::s
V)
~

(;j
;.

7

0.064

2,060

32

1.6

2,490

49

2.0

EMS

UV

100
50

0: Wild type (ILl66-6b)6. : Mutant (FL 67)

25

~

20

Q)

15

10
5

10

~

u

c:
0

'(J
<;::
0

"0

~

.g

5
ll.

1
0

- ------

10,795

Ne beamwere replicated to other three glycerol plates. These
plates were independently incubated for 5 days at 16
30 , and 37°C. The cells that were able to grow at 30°C:
but not at 16 or 37°C, were counted as the TS mutants.
We observed that the mutation rate induced by theirradiation of Ne ion was 25 or 31-fold lower than thattreated by EMS or UV irradiation. We can consider apossibility that the heavy ion caused mutations by anmechanism different from the cases of UV and EMS .
Then, we examined effects of irradiation of N e ion
on induction of the respiration-deficient progenies from
FL67 (mhrl-l) mutant . The higher rate of such induction than the case of wild type cells was regarded due
to a deficiency in mitochondrial DNA repair.3 ) We observed that a very low fraction (less than 3%) of viable
cells lost its respiration function at a mortality of 30%(Fig. 2). However, at the same mortality caused by
UV irradiation, the FL67 mutant produced more than
45 % of respiration-deficient progenies. 3 ) This result hassuggested that heavy-ion beam induced such damagesof cells that can not be repaired by mitochondrial recombination. DNA double-strand breaks were shown
to be repaired by the genetic recombination in variousorganisms. Thus, our results suggest either that the
double-strand breaks are not major DNA lesions, orthat the DNA damages are not a major cause of thedegenerative effect of heavy-ion beam in mitochondria.

Cii

~
~ 10

Mutation rate
(10- 2)Viable cells

TS : Temperature Sensitive

~

100
50

TS mutants

Mutagen50 100 150 200250

0

~

'0..
OIl
0

IX

Dose (Gy)

'E 5
:l

(/)

1 ~~~~~~~~~--~~~

o 50 100 150200 0 250500 7501000 1250
Dose (Gy)Dose (Gy)Fig. 1. Survival curves of yeast cells after irradiation ofheavy-ion beam.
College of Bioresource Sciences, Nihon University

148

Fig. 2. Effect of heavy-ion beam on induction of respiration deficient cells.
References
1) T. C. Akpa et aI.: Int. J. Radiat. BioI. 6 2, 279 (1992).
2) K. J. Weber et aI.: Int. J. Radiat. BioI. 64, 169 (1993) .
3) F. Ling et aI.: EMBO J. 14,4090 (1995).

RIKEN Aeeei. Prog. Rep. 32 (1999)

Effects of Heavy-Ion Beams on Radio-Sensitive
Mutant Cell Lines
K. Eguchi-Kasai, H. Itsukaichi, M. Murakami, T. Kanai, F. Yatagai, and K. 8ato*
Main cause of severe lethal effect by the high Linear
Energy Transfer (LET) radiation to include heavy ion
beams is due to a high induction of non-repairable double strand breaks (dsb). The Relative Biological Effectiveness (RBE) of the high LET radiations for total
dsb induction is not large compared with their lethal
effect. The ratio of non-repairable dsb to total dsb increases with LET. But the nature of non-repairable dsb
is not clear, nor is it that repair system really acts withthe strand breaks induced by ion beams with veryhigh LET, because every method which is employed
to detect dsb actually detects not only dsb but single
strand breaks (ssb) etc. Here, we compared the effects of charged particles on cell killing in a pair of themouse cell lines which are normal (LTA) or defectivein the repair of DNA dsb (8L3-147).
Charged-particle beams used were Ne ion of
135 MeV /u, Ar ion of 83 or 90 MeV /u, and Fe ion of
90 MeV /u. Inactivation cross sections were calculated
from 37% survival dose of the survival curves fitted
by a linear regression analysis to the linear quadraticmodel.
In the dsb repair deficient cells, the RBE values
were close to unity for the cell killing induced bycharged particles with the LET up to 200 ke V / /-lm,
and were even smaller than unity at the LET region
larger than 300 keV/J-Lm (Fig. 1). The inactivation
cross section (IC8) increased with LET for both celllines (Fig. 2). The ICS of dsb repair deficient mutants is larger than that of their parents for the LET
up to 2000 keV / /-lm. With increasing LET, the difference of IC8 between the mutant and its parent became
smaller. This suggests that the repair system of parent cell line did not work well for the breaks inducedby high LET ion beams. That is, repairable dsb decreases, and the ratio of non-repairable dsb to total
dsb increases with increasing LET. This difference in
ICS disappeared at the LET of about 3000 ke V / /-lm ..

4

UJ 3

m

a:

o

2

I'
1

o 1

•

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

10

10

2

10

3

10

4

LET (keV/llm)
Fig. 1. RBE of heavy ion beams for cell inactivation.
Closed symbols represent the dsb repair deficient cells(SL3- 147) and open symbols the wild type cells (LTA).

-

.,

( 'II

eE

Fe

c

6.

0

:s

10~

CD

en
en
en

0
a..

(,)

C
0

;:
cu
>
;:
(,)
cu

.E 10.7
10'

10 2

10 3

LET (keV/pm)
Fig. 2. Inactivation cross section of heavy ion beams.
Symbols are the same as in Fig. 1.

School Biology-Oriented Science and Technology, Kinki
University

149

RIKEN Accel. Prog. Rep . 32 (1999)

Potentially ,L ethal Damage Repair on the Human Skin Fibroblasts
Irradiated with Ar Ions
H. Maezawa and F. Yatagai
Previously it was reported that the carbon ionsabove 58 ke V / J..Lm produced less repairable damage infibroblasts. I} For C ions (135 MeV/nucleon) the LET
from 22 to around 300 ke V / J-Lm was available. Higher
LET ions around 1000 keY / J-Lm, which is given by
Ar ion, might produce different types of damage fromaround 100 keY / J-Lm. Present study was conducted
to find the relative biological effectiveness (RBE) of
lethal sensitivity and potentially lethal damage repair(PLDR) in normal human skin fibroblasts after the irradiation of Ar ions.
Fibroblasts were grown (at 37°C) to a stationary
phase in plastic flasks (T25), and were irradiated (atroom temperature) with the Ar ions accelerated to
95 MeV /nucleon by RIKEN Ring Cyclotron. Using thequasi-monoenergetic ion beam, different LETs (2961597 keY / J-Lm) were produced by inserting absorberplates of appropriate thicknesses. Cells were resuspended by trypsinization immediately after irradiation, and were plated for colony formation. In PLDR
assay cells were incubated for 24 h at 37°C after irradiation, and then plated.
Figure 1 shows the survival of fibroblasts with andwithout PLDR. At 306 ke V / J-Lm cells were killed exponentially with increasing dose. There appeares ashoulder on the survival curve at 1597 ke V / J-Lm. After repair-incubation for 24 h the survival increased
at 1597 ke V / J-Lm, but did not at 306 ke V / J-Lm. These
results indicate that the characteristics of damage aredifferent between 306 and 1597 keY / J-Lm. It is interested that the particular group of damage produced
by Ar ions at 1597 keY /J-Lm is repairable. RBE (whichis the ratio of the dose required for 10% survival with
Ar ions to that with Co-60 gamma-rays) at a given
LET is shown in Fig. 2. RBE decreased with increasing LET values from 296 to 1597 keY / J-Lm and reached
to around 1 at 1000 keY / J-Lm.
Present results suggest a possibility that the radiation, such as Ar ions, above 1000 ke V / J-Lm produces less-cytotoxic and more-repairable damages ascompared with the radiation at lower LET (100300 keY / J-Lm).

150

\

Ar-40
HSF

\

~

•~

0.1

-;
.?:

'~

~

'~

~

:J
U)

O,~

0.01

'"Ll
,
'.\
-o-SF1597(-)'.\___ Sf1597(+)- . -SF306(+)--o--SF306(-)

'.'

'.'

'\

0.001
0

2

3

4

5

6

7

Dose(Gy)

Fig. 1. Survival curves with (closed) and without (opened)
PLDR of human fibroblasts irradiated with Ar ions.

LU
In

a:

LET (keV/micron)Fig. 2. LET-RBE relationship of fibroblasts exposed to
Ar ions.

References
1) H. Maezawa and F. Yatagai: RIKEN Accel. Prog. Rep.
28, 116 (1995) .

RIKEN Accel. Prog. Rep . 32 (1999)

Judgement on· "Hit or Non-Hit" by Time-Lapse Observations of
CHO Cells Exposed to Accelerated Iron-ions
H. Sasaki, P. Mehnati,* F. Yatagai, and F. Hanaoka
It is well known that the cell killing effect of ionizing radiation depends on the linear energy transfer (LET) and that its relative biological effectiveness(RBE) reaches a maximum at an LET of around100- 200 ke V / pm and then decreases with further increase in LET. To answer why the cell killing effect decreases with extremely high-LET radiation, an "OverKilling Effect" hypothesis has been proposed. However, an alternative explanation is possible on the basisof microdosimetric points of view. Since the distribution of ionization is sparse and homogeneous for lowLET radiations but it is dense and concentrated forhigh-LET radiations, the probability that no ionization
occurs within the cell target is much higher for the latter than for the former radiation when compared at thesame dose level. Assume that cells (target = nucleus :",130 pm 2 ) are exposed to 4 Gy of accelerated ironions (LET: 2000 ke V / pm). After converting the dose
(4 Gy) to the fiuence (1.25 X 10- 2 / pm 2 ) and assumming a Poisson distribution of hit-events, the fractionof cells whose targets are not transversed by iron-ions(non-hit) was calculated to be about 20%. This value
is roughly equal to the surviving fraction (about 30%)of cells after exposure to 4 Gy of iron-ions.
Division delay is an early cellular response in which
all irradiated cells, except those in late G 2 /M phase,are temporarily prevented from undergoing G 2 /M
transition and cell division. In this study, we have tried
to measure the fraction of non-hit cells using the division delaly as an indicator of a "hit". Whether divisiondelay did occur or did not occur (hit or non-hit) was
determined for individual cells which were observedwith time-lapse photography before and after exposure to 4 Gy of iron-ions (LET: 2000 ke V / pm). Results are shown as pedigrees of individual CHO (Chinese hamster ovary) cells in Fig. 1. In Fig. 1, arrows
indicate the point where cells were exposed to ironions and the numbers on the left and right sides of thearrows correspond to the time after division at irradiation (cell age) and the time interval from irradiation
to post-irradiation first division , respectively. Therefore, the sum of these two numbers correspond to thecell cycle time at the irradiated generation. As seen
for No.5, 6 and 7 cells, the cell cycle time at the irradiated generation is apparently prolonged as compared to that before irradiation (12- 13 h). Furthermore, the cell abnormality such as incomplete division
leading to sister-cell fusion and binucleate-cell formation took place for No. 7 cell. Therefore, these cells
were judged as hit-cells. Whereas, No.8 cell showed
no division delay at the irradiated generation, and continued dividing with cell cycle time similar to those of
non-irradiated cells. Consequently this was judged asa non-hit cell. Twenty five non-hit cells were found in a
Faculty of Medicine, Kyushu University

Fig. 1. Pedigrees of CHO Cells Exposed to 4 Gy of accelerated iron-ions (LET: 2000 ke V / /-LID) .

total of 136 cells. The fraction of non-hit cells (25/136:
18%) is comparable to the value calculated according
to a Poisson distribution of hit-events (about 20%) but
slightly lower than the surviving fraction (about 30%).
This suggests that some hit-cells can survive even after
exposure to an extremetly high-LET radiation. An example of the pedigree of surviving hit cell is shown in
Fig. 2. On the other hand, CHO cells exposed to 4 Gyof X-rays (30% survival) were also observed by thetime-lapse photography. However, non-hit cells suchas those found in the iron-irradiated cells could not be
identified.

8

~ 14

12

Fig. 2. A pedigree of CHO Cell which retained a reprodutive capacity after exposure to 4 Gy of accelerated
iron-ions.
151

RIKEN Accel. Prog. Rep. 32 (1999)

Apoptosis Induction and Cell-Cycle Change of Human Cancer
Cell-Line Caused by Heavy-Ions and X-Rays
N. Shigematsu,* S. Yamashita, N. Ihara,* T. Kawata,* S. Kutsuki,* K. Toya,*
A. Kubo,* H. Ito, T. Kanai , Y. Furusawa, and F. Yatagai
A number of studies have been carried out about
apoptosis by applying X-ray irradiation thus far, but
the studies reporting about the apoptosis induction after heavy-ion irradiation is very few. This article is apreliminary report for comparison between heavy-ion
beam and X-rays over the apoptosis induction ability
on cultured cells. Previously, we reported that heavyion beams (carbon and neon) showed much more powerful cell-killing effects than X-rays, and showed thehigher frequency of DNA mutation compared with Xrays. I) During this reporting period, we investigated
the apoptosis induction and cell-cycle change after irradiation using three human cell-lines: MDA-MB231(breast cancer origin), T24 (bladder cancer origin) andKB3-1 (epidermoid cancer origin). JURKAT (humanT-cell lymphoma origin) was used as a control to see
the apoptotic effect. The heavy-ion beam which we
employed this time was a carbon beam at the energy of 290 Me V / u. Cell apoptosis was detected byflow-cytometer using AP02.7 monoclonal antibody.
AP02.7 is an antibody against the 7A6-antigen which
is 38kD protein and appears at mitochondrial membrane of apoptotic cells. 2 ,3) Cell-cycle was also analyzed by flow-cytometer. Cells were harvested andthen analyzed by flow-cytometer, by the procedure asshown in Fig. 1. Typical charts of flow-cytometer isshown in Fig. 2.
Big shift to G2 was observed after X-ray (150 kV)
irradiation, and this effect was dose-dependent. Apoptotic fraction increased with dose, but it reached to aplateau around 50- 60% at the dose of approximately
15 Gy. These effects were observed also in the othercell lines we used (Fig. 3).
lOGy

Control

Apoptotic cell fractioD

~
26-;"

1-;.

20Gy

ISGy

~
75%

74-;.

Fig. 2. Apoptosis induction and cell-cycle change in the
MDA-MB231 cell-line at the time 72 h after X-ray irradiation.
100

cell suspension ( ....... l06cells )

~

-!..

cL.I spin (1500rpm, Gmin, room temp.)

v.l---v.l~pellet~ PBS2mi~

digitonin
0<100/.1.1 (100 /.1. g/ml)

0

C, 20min)~ PBS2ml

20 /.1. 1

incubation (room temp.. IGmin)~PBS2ml

petlet~PBS 1ml
flow -cytometer analysis

Fig. 1. The procedure outline of detecting apoptosis.

152

30

(Gy)

.

c..b spin (lGOOrpm, 6min, room temp.)
I

Department of Radiology,
University

20

Fig. 3. Apoptosis induction curves of MDA-MB231, T24 ,and KB3-1 against X-ray dose, comparing with JURKAT as a control.

pelletAP02.7

10

IRRADIATION DOSE

7 spin (1500rpm, amin, room tempJ- ---'--.,

If-

T24

~

I
pelletincubation (4

KBJ·l
50

0

J..,
., spin (lGOOrpm, 5min, room temp.)

I

JURKAT........

School of Medicine,

Keio

This observation was not caused by the procedure
itself, since the similar experiment using JURKAT
cell showed a quite high frequent apoptosis with thismethod. The effect of carbon beam irradiation onthese cell-lines was very similar to that of X-ray. In
summary, G2-block was observed after carbon beamirradiation, and apoptosis occurred with dose dependent and then reached to a plateau around 60- 80% at
the dose of apploximately 4-6 Gy (Fig. 4).

The reason why such a different effect was observedby heavy-ion beam and X-ray can not be explained
now, since a number of cell lines is too small to explain
whether it was caused from specific cell-line or specificheavy-ion particle. Elaborate analysis will be continued by using other human cell-lines and with otherkinds of heavy-ions (e.g., neon- and argon-beams) .

100

~
~

CI.l

0

E-4

50

~

0

tl.

-<
0

2

4

IRRADIATION DOSE

6

8

(Gy)

Fig. 4. Apoptosis induction curves of MDA-MB231, TE24,
and KB3-1 against the carbon beam dose.

References
1) T. Kawata et al.: RIKEN Accel. Prog. Rep. 31, 149(1998).
2) S. K . Koester et al.: Cytometry 29, 306 (1997).
3) C. Zhang et al.: J. Immunol. 151, 3980 (1996).

153

RIKEN Accel. Prog. Rep. 32 (1999)

Influence of p53-Gene Function on the Specificity in hprt
Mutations Induced by Heavy-Ions
S. Morimoto, A. Gordon, N. Fukunishi, F. Hanaoka, and F. Yatagai
An attempt has been made to elucidate the mutational specificity of the heavy-ions at various LET (Linear Energy Transfer), which may contribute to the estimation of radiation risk as well as to the basic understanding of mutation induction mechanisms. The LET
is defined as the energy deposition along the heavyion truck and usually considered as an expression of
the status of initial interaction with the matter. Since
the risk of exposure to high-LET heavy-ions seems to
be increased in recent days, we have focused our effort on such radiation-induced mutations in humancells. It is also of our interest to study the natureof mutations caused by such a high-LET radiation,
which is suggested to produce a DNA damage different
from that produced by conventional ionizing radiation.
In fact, our analyses of hypoxanthine phosphoribosyltransferase (hprt) mutations in human cultured cells
revealed the heavy-ion energy dependent mutational
spectra. For example, this is a high frequency recovery of the point mutations caused by a high-level of
LET, in which ions will lose most of their total energy and stop shortly after passing the cells. 1- 3 ) In thissame energy region, we have also observed the mutational events that represent complex loss of multiple
non-contiguous exon regions. 3 )Recently, the tumor suppressor gene p53 has cometo be regarded as a guardian of cells against not only
radiation but also various chemicals. Along this line,
the influence of mutant p53 gene on X-ray-induced
mutagenesis has been studied by some groups using
the human lymphoblastoid cell lines derived from thesame human spleen, WI-L2-NS (mutant p53) and TK6(wildtype p53). We extended this type of approach tothe hprt mutational peculiarity studies for heavy-ions.
Similar to the results of X-ray irradiation,4) WI-L2NS was more radioresistant and mutable than TK6
after the C-, Ne-, and Fe-ion irradiations at a particular level of high beam-energy (LET: 22, 67, and 1000
keY / J,Lm, respectively). (Fig. 1 and Table 1). The hprt
mutations obtained after the irradiations of above ionswere analyzed mainly by the multiplex PCR of exon region. After the C- and Fe-ion irradiations, a relatively
frequent recovery of point mutation was observed in
WI-L2-NS compared to the TK6 cells (Fig. 2). A
majority of the mutations recovered after exposure to
Ne-ion was a partial deletion event in both two celllines, but deletion events on the 5'-side of the gene
were found in only TK6 cells (data not shown). Since
characteristic of the Ne-ion induced hprt mutation is

154

s::

0.1

0

'p

u

CIS

<l::
et)
s::

'> 0.01
'E
='

CI)

0.001

2

0

3

4

Dose (Gy)Fig. 1. Survival curves against 22 ke V / J..Lm C-ions.
Table 1. hprt mutation induction after the exposure ofheavy-ions.
TK6
Ion(LET: ke V/~m) Dose(Gy)
C (22)
2.0
Ne (67)1.0
Fe (lOOO)
2.0

SF

MF(X 10-6 )

0.058
0.056
0.24

7.2
9.9
7.6

WI-L2-NS IWTK1~Dose
MF (X 10'" )
SF
(Gy)
2.4
0.068
9.8
1.2
0.14
31
2.4
17
0.27

SF: Surviving fraction
MF: Mutation frequency

C(22)Ne(67) Fe(1000)

C(22)Ne(67) Fe(lOOO)

Fig. 2. Relative distribution of the hprt mutational classes
determined by multiplex PCR pattern: (a) TK6 and (b)WI-L2-NS. Here, .: point mutation (normal amplification), 0: partial deletion (some regions are amplified),and 111: complete deletion (no amplification).

quite peculiar, we plan to do the experiment to confirm
the results. The peculiar differences of the p53 genefunction are significant, which requires further study.
References
1) M. Suzuki et al.: Adv. Space Res. 18, 127 (1995).
2) Y. Kagawa et al.: J. Radiat. Res. 36, 185 (1995).
3) Y. Kagawa et al.: Mutagenesis, in press.
4) E. N. Phillips et al.: Radiat. Res. 143 , 255 (1995).

RIKEN Accel. Prog. Rep . 32 (1999)

Induction of p53 and p21 in Human Cells after
Heavy-Ion Irradiations
A. Gordon, N. Fukunishi, and F. Yatagai
Recently, the tumor supressor gene p53 has cometo be regarded as a guardian of cells against not only
radiation but also various chemicals. Damaged DNA
can trigger the p53 checkpoint response, p53 centeredstress signaling can determine the fate of a stressed
cell. As a transcription factor, p53 upregulates many
genes including WAF-l (p21). To assess the influenceof mutant p53 gene on mutagenesis, we have undertaken the elucidation of the mutational specificity ofheavy ions of various LET (Linear Energy Transfer) .
The induction of p53 and p21 after X-ray irradiation
has been extensively studied by many groups using human lymphoblastoid cell lines derived from the same
human spleen, namely, cell lines WI-L2-NS (mutant
p53) and TK6 (wildtype p53).1) After irradiation (Cion of 22 ke V / J-tm and Fe-ion of 1000 ke V / J-tm as wellas X-ray irradiation), both p53 and p21 proteins were
induced in the TK6 cell line (Fig. 1). However, p53
and p21 were not induced in the WI-L2-NS cell line
after any type of irradiation including the above heavyion; p53 was constitutively expressed and p21 was notproduced (due to the mutant nature of p53). This isconsistent with the results of Little. 2 ) for the same/or
similar cell lines. The type of irradiation did not alter
the p53/p21 response of each cell line. The significance of this response in relation to the specificity ofheavy-ion induced hprt mutations is now under study.

Dose (Gy)

p53

...

p21

...

X-ray

C-ion
22 keVlJ.1m

Fe- ion1000 keV/J.1m

TK6

TK6

TK6

0

WI-L2-NS3

0

3

WI-L2-NSo 3 0 3o

WI-L2-NS3

03

Fig. 1. Western Blot analysis. The protein was extracted
2 h after 3 Gy irradiation of 2 x 10 7 cells. Equal amounts
of protein (60 J.Lg) were loaded into each lane in a 15%
SDS-PAGE mini-gel, electrophoresed, and blotted onto
a PVDF membrane and probed with monoclonal antibodies against p53 (DO-I, Santa Cruz Biotech) andp21 (EAIO, Oncogene Sciences). Each panel represents an independently processed blot and therefore
only qualitative comparison may be made between panels.

References
1) S. A. Amundson, F. Xia, K. Wolfson, and H. L. Liber:
Mutat. Res. 286, 233 (1993).
2) J. B. Little, H. Nagasawa, P. C. Keng, Y. Yu, and C.
Li: J. BioI. Chern. 270, 11033 (1995).

155

RIKEN Accel. Prog. Rep. 32 (1999)

Heavy Ion Beams: An Application to Mouse Mutagenesis
A. Yoshiki, N. Hiraiwa, T. Tsukada, Y. Yoda, C. Poirier, F. Ike,
N. Fukunishi, M. Kase, Y. Yano, and M. Kusakabe
Mouse mutants are a quite useful animal model tostudy the gene functions and pathogenesis of humandiseases. However, we do not have enough kinds ofmutants with phenotypes which reveal functions of all
the genes and which correspond to every human diseases. For this reason, we need more effort to create
and find new phenotypes in mouse mutagenesis. In thispaper we report an application of heavy ion beams formouse mutagenesis.
C57BL/6J (B6) mice were used for this experiment.
Mature males were sacrificed by cervical dislocation
after anesthesia, and the cauda epididymidis were removed from the testes. Postmeiotic incapacitated spermatozoa were collected from the cauda epididymidis bya fine-needle, suspended in 1.5 ml centrifuge tubes containing 1 ml of M2 medium,l) and stored at 4 °C until
irradiation. The tubes were centrifuged briefly at room
temperature, and were exposed to heavy ion beams(40 Ar at 95 MeV lu, 56Fe at 90 MeV lu, and 2oNe, 14N
and 12C at 135 MeV lu) with dose ranges of 5, 10, 20,
30, 50, 75, and 100 Gy at RIKEN Ring Cyclotron Facility. After irradiation, sperm suspensions were stored
at 4 °c until manipulation. Mice were created artificially in vitro by using a micromanipulator as shownin Fig. 1. Mouse eggs were collected from oviducts
after treating females with pregnant mare's serum gonadotropin and human chorionic gonadotropin . The
eggs were held by a holding pipette, a single spermatozoon was picked up by another micropipette andinjected into the egg cytoplasm (Fig. lA). Manipulated eggs were incubated in M16 medium 1) overnight,
then successfully cleaved 2-cell embryos (Fig. IB) weretransferred into oviducts of pseudopregnant mothers
to produce GI mice. GI mice were crossed with wild
type B6 mice to produce G2 mice. G2 mice were
backcrossed to GI to produce G3 mice. GI and G2
mice were screened for dominant mutations, and G3 forrecessive mutations. So far we found external anomalies in G1, G2 , and G3 generations as summarized inTable 1.
We have also tried to induce mutations in male premeiotic germ cells. B6 male mice were deeply anesthetized with 10% nembutal solution, and their hypogastric and scrotum regions were exposed to heavy
ion beams (40 Ar , 56Fe , 20Ne , 14N , and 12C) with dose
ranges of 0.5, 1, 3, and 5 Gy. Testis tissues wereseverely damaged after irradiation. Germ cells in
seminiferous epithelium decreased significantly with ahigher dose of heavy ion beams. Following the sterile
periods , some male mice could restart reproduction.
We have paired irradiated males with untreated females to produce G I mice. We examined these G 1
generation during embryonic periods for morphological anomalies to assess which male mice have highpotential to produce mutants more effectively. In G I
embryos morphological anomalies were found in different organs and systems , such as microphthalmia,
anophthalmia, exencephaly, edematous skin, and paleanemic embryos. In further study we plan to selectseveral irradiated male mice as potential breeders for
efficient mutant production.
Table 1. The LET of 12C, 14N, 2°Ne, and 56Fe ion beams
were 23, 31 , 61, and 620 keY / /-Lm, respectively. Here,Gen. denotes the generation of mice.

Beam DoseGen.

Affccted tissue!
organ/system

Anomaly30

01

coat color

non·pigmented hair around eye. and on the back

"N

10

"N

50
10

01
01

reproduction

01

skin, eyereproduction
hair. eye

"C

~Ne

"Ne

10

01

"Ne

JO

01

"Ne
"Ne

10

01

50

01

"Ne

50

01

eye

"C

30

02

coal color

''C

30

02

hair

<terile female
dermatitis and corneal inflamation
steri Ie malecomplete loss of hair and microphthalmia

hair. skin. eye complele loss of hair. dennatilis and caUlraCI
tailround lai I tip
cataract and anophthalmia
many non-pigmented hairs
loss of hair or naked

30

02hair. eye

75

G2

tooth

"N

50

02

eye

long teeth
cataraci

uN

50
50

02
02

tooth

long

reproduction

50

02

lail

G3

brain. eye

03
G3
03
03

tooth
eye
skeleton

"N
UN

uN
uN

30
50

"Ne

20
20
20

~Ne

"Ne

156

cataracl' Fe"C

Fig. 1. (A) Microinjection of irradiated sperm cells into
the egg cytoplasm. (B) A successfully cleaved 2-cellembryo after sperm injection. Length of bar: 50 /-Lm.

eye

No. of miceskin

microphthalmia and hair loss

vagina not open
kinkyhydrocephalus and anophthalmia
hypcpigmentalion until 10 days of age
long
microphthalmia
abnonnal shape ofvenebrate

References
1) B. Hogan et aL: in Manipulating the mouse embryo, 2nded. (Cold Spring Harbor Laboratory Press, New York,
1994), p. 385.

5. Instrumentation

RIKEN Accel. Prog. Rep . 32 (1999)

Measurement and Simulation of the GARIS Quadrupole Magnet
K. Uchiyama, K. Morita, and Y. Tagaya
For the past few years , several experiments for producing and identifying new isotopes have been performed using the GAs-filled Recoil Isotope Separator (GARIS).!) The GARIS consists of three magnets
which are arranged in a D-Q-Q configuration. It was
found recently that the maximum magnetic field gradients of these two quadrupole magnets are not highenough to focus the recoils heavier than transactinide
region onto a proper point. Trajectory of the 272 108
which can be produced by the reaction 238U (40 Ar,a2n) was calculated using the TRANSPORT code. 2)
The magnitude of the dipole magnet field was estimated to be 15.21 kG under the assumption that therecoil energy of 272 108 is 29.0 MeV in the laboratory
frame and equilibrium charge is 5.84. The values offield gradient of the quadrupole magnets are set tothe maximum ones, 52.0 kG/m. From the results ofthis calculation, the image size on the focal plane of
GARIS was found to become 13.4 cm horizontally and48.8 cm vertically. This does not satisfy the double focusing condition at all. Obviously, an improvement offocusing elements is needed for the GARIS. Thus, wehave performed a simulation of magnetic field of thequadrupole magnet in order to search for the method
how to improve the GARIS.
Both quadrupole magnets are identical, whose pole
length is 500 mm and bore radius is 150 mm. The
pole length is much shorter compared with the bore
radius. Therefore, a three dimensional simulation isrequired to take into account of the fringing-field correctly. Figure 1 shows the magnitude of vertical component of the magnetic field in the median plane at
108 mm away from the center point, as a function of
the current drawn by the coils of quadrupole magnet.
The open squares denote the measured values, while
the solid line shows the three dimensional calculation
result obtained by using the computer code TOSCA.
The calculation well reproduces the measured values.
The error of these simulation results is less than 1%.
The saturation occurs at and over 200 A.
In order to achieve the double focusing condition forthe case of 272 108, the field gradient 85.6 kG/m for
the Q1 and 83.3 kG/m for the Q2, that is 9.24 kG and
8.99 kG at 108 mm away from the center respectively,
are required. The double focusing condition was calculated by the TRANSPORT code. But, it is not arealistic solution to increase the current drawn by thecoils. Figure 2 (B) shows the magnitude of magnetic
field of the iron and air regions along the center line ofthe pole piece. The current for the coils was the maximum current , 350 A. It was found that the saturation
mainly occurs in the pole piece which is wrapped by
the coil. Therefore , it is impossible to add the ironto the saturated place, although this is one of the solutions to ease the saturation usually. Consequently,
if we stay with the same geometry, we should change
the design of the quadrupole magnet to the one whosepole piece is thick enough not to cause a saturation.
It will be then possible to achieve the double focusing
condition using the same magnets. But, in the lattercase we will lose the total collection efficiency due tothe smaller acceptance angle. The future plan of the
GARIS is under discussion.

(A)

25000

Air

Air

';;;"

il
Q

20000

(8) J

15000

J

10000

.11

II

go

5000

2
15

30

45

60

75

90

Oi,lance [em)

8000
7000

~

6000

!2.

5000

iil

"0

"iii

u::

.!<

~

g'
:2

4000
3000
2000
1000
100

200

300

400

500

600

700

Current [AI

Fig. 1. The magnitude of vertical compon~nt of the magnetic field in the median plane at 108 mm away fromthe center as a function of the input current. The open
square and the solid line denote the measured and calculated values, respectively.

Fig. 2. (A): Schematic of the quadrupole magnet. The
eight pentagons show the cross sections of the coils. The
arrow corresponds the abscissa for Fig. 2B. (B): Magnetic field strength in the iron and in the air along thecenter line of the pole piece. The current drawn by thecoils was 350 A. The abscissa shows the distance fromthe center of the quadrupole magnet. The four regionsof quadrupole magnet (air region inside the magnet,
pole piece, return yoke, and outer air region) are indicated in the upper part of this figure.

References
1) K. Morita et al. : Nucl. lnstrum. Methods Phys. Res. B
70, 220 (1992).
2) K. L. Brown et al. : SLAC-91 , Rev . 1 (1974).

157

RIKEN Accel. Prog. Rep. 32 (1999)

Simulation of the Ion Trajectories in the Gas-filled Recoil Separator
Y. Tagaya, K. Morita, K. Uchiyama, and T. Nomura*
The RIKEN gas-filled recoil separator (GARIS)1)
was designed to separate the fusion reaction products from the primary beam with a high transmission efficiency. Many new isotopes have been produced and their decay properties determined in thoseexperiments 2 ) using the GARIS. Cross-sections besides
their decay properties of isotopes are of great physicalinterest. However, we can not discuss them because of
the ambiguous transmission efficiency of the GARIS.
Therefore, we are currently improving the simulation
code 3) of the ion trajectories in the GARIS in orderto calculate its transmission efficiency followed by theexperimental cross-sections. The code is also useful todetermine the parameters of: the dipole magnet, twoquadrupole magnets, and gas pressure of the GARIS
prior to the experiment.
Trajectory of ions is governed bydv-

m dt = qv x B,
where m is the ion mass , v the ion velocity, q the ion
charge and B the magnetic flux density. This equation
can be solved by the Runge-Kutta method, and thewhole trajectory from the target position to the focal
plane can be calculated. The images of particles at thevarious planes can be drawn by the two-dimensionalplots. The energy and angular spreads of the ion in theenergy degrader and target material, both of which areat the target position, are taken into account to calculate the image size correctly. The vertical components
of magnetic flux density at the medium plane (Byo)were calculated to fit with the measured data and all
the other components were calculated from the Byo by
the expansion equations.
To check the magnetic flux density in the code, we
performed the simulation of the experiment, in which
36 Ar 5 + ions passed through 1.5 J.Lm Al foil at the target position and various charge states of 36 Ar were created. In the experiment , the magnetic flux density waschanged for each charge state of 36 Ar , so that the image
center appears at the focal position of the GARIS andthe transmission efficiency becomes maximum. TheGARIS was kept in vacuum, so the collisions of theions with the gaseous molecules can be ignored. The
step size of the calculation Idil, in which i is the ion
position, was fixed to 1 cm which was small enoughnot to introduce much of calculation error.
Figure 1 shows the calculated image of 36 Ar 13 + ions.
The calculated image size (FWHM) was 0.7 cm in horizontal direction and 0.9 cm in vertical direction, while
the measured image size (FWHM) was 1.0 em in both
directions. This discrepancy is probably due to the calculation of the angular spreads of ions,4) which is not
KEK Tanashi

158

s
()

'"2'

:3"c;j

0

o
0..
~

~

...

- 1

Q)

:>

2

3

4

5

Horizontal Posilion[ em]Fig. 1. Calculated image of 36 Ar 13 + ions at the focal
plane. The horizontal position of the image increases
as the value of the magnetic rigidity increases.

optimized for the Ar-AI combinations at the energiesof this experiment.
Figure 2 shows the calculated horizontal positionsof the image center at the focal plane for all charge
states. The deviations of the calculated positions fromthe experimental ones were between 3 cm and 5 cm
on the high magnetic rigidity side. This suggests thatthe magnetic flux density in the code is slightly weaker
than the actual field at the same current. Change ofthe fringing magnetic flux density of the GARIS dipole
magnet at a high current, which is not included in thecode, probably causes the enhanced shifts for the low
charge state ions. We are now modifying the magnetic
flux density in the code to reproduce the experimental
results.
6

S

I

I

I

I

I

I

~

:§

-

5-

j:l

0
N

.~

.J::
0

::r:

$:;'

-

H --

., ., ., ., .,
., .,

v

-;::
v

u

.e;;e

3 -

&
~
Q)

j:l
tl()

., -

Q)

«l

:::<1

tl.O

<C

.§
I

I

I

I

I

I

10

12

14

16

18

Ion Charge

Fig. 2. Calculated horizontal positions of the center ofthe image at the focal plane as a function of the ion
charge state. The horizontal positions derived from theexperiment were at 0 em for all charge states.

References
1) K. Morita et al.: Nucl. Instrum . Methods Phys. Res. B
70, 220 (1992).
2) For example, K. Morita et al.: Z. Phys. A 352,7 (1995).
3) A. Yoshida: Tokyo lnst. Technol., Master thesis (1989).
4) J. D. Jackson: Classical Elecrtodynamics, Chapter 13.

RIKEN Accel. Prog. Rep. 32 (1999)

New Data Acquisition Systems for the Spectrograph SMART
H. Okamura
Two types of data acquisition (DAQ) system havebeen introduced for the experiments at E4 area. Theircommon features are: (a) the cost-effectiveness realized by the use of personal computers (PC) runninga free UNIX-clone, Linux, (b) the network capabilities
which allow on-line analyses and/or the data recording
on remote machines, and (c) the graphical user interface (GUI) composed by using Tcl/Tk. 1)
The first type is a high-speed DAQ system, about
ten times faster than the previous one,2) but dedicatedto the use of LeCroy 4300B (FERA) and FERA compatible modules, such as LeCroy 3377 drift-chamber
TDC. These modules are reasonably fast and commonly used in medium-scale experiments, but the low
band-width of CAMAC bus becomes a "bottle-neck"limiting the total DAQ speed. In the present system,
instead, data are accumulated in a CES High Speed
Memory (HSM) 8170 on VME through the FERA bus(20 MB/sec at maximum), and are DMA-transfered toa PC through a Bit3 617 VME/PCI interface (and optionally through a Bit3 400-5/50 optical link) at eachtime when a 64-kB block is filled (Fig. 1). The device
driver for Bit3 617, developed at NIKHEF, is used,3)but modified to handle interrupts from the VME bus.
It should be noted that there is no CPU on the VME
bus, and the resource additionally required is verysmall.

instead, considerably depends on the event rate as wellas on the system load, as summarized in Fig. 2.
The second type DAQ system is a conventional one
using an intelligent auxiliary crate controller (ACC)on the CAMAC bus. It is a renewal of the previous system 2) which consists of aCES 2180 ACC, a
Kinetic 2922 Q-bus interface, and a VAX/VMS hostcomputer. They were replaced with a Kinetic 3976
68030-based ACC, a Kinetic 2915 PCI interface, anda PC running Linux, respectively. The Kinetic 3922
crate controller is still used because of its cable-driver(up to 90 m) and DMA capabilities.
The source code, previously running on CES 2180,
has been ported to Kinetic 3976 by K. Yoshida, 4) andis assembled by the assembler written by M. Iwasaki. 5 )The device driver for Kinetic 2915 developed at NIAS
and Jefferson Lab. is used,6) but was extensively modified for stable and efficient DMA operations.

CAMAC

3

10

2

Data Recording
Event Rate 1 kcps
Live Time 98%
Data Rate 114 kB/sec

W/ 0

1

10
10°
()
Q)

1/1

E 10

0

VME

10

3

w/o Dato Recording
Event Rote 31 kcps
Live Time 57%
Doto Rate 2 MB/sec

10 21';;;- 10
~ 10°
~

III

3

10
2
10
10 1
10°

7

8

9 10
20
Transfer Period per Block (msec)

30

Fig. 2. Typical distribution of DMA-transfer period undervarious conditions. Triggers were generated by a random pulser with an event-length of 57 (16-bit) words.
The block size is 64 kB.

Fig. 1. A simplified scheme of the FERA/VME-based
data acquisition system. For polarization experiments,
the 4-gate 16-channel VME scaler, V-TS801, has been
newly fabricated by Technoland Corp.

Since HSM 8170 allows a memory access from the
FERA bus even when a DMA transfer is in progresson the VME bus (i.e. "double-buffer" mode), the DAQ
speed is not affected by the system load in spite of thefact that Linux is not a real-time OS. The DMA speed,

References
1) Tcl/Tk, http://www.tclconsortium.org.
2) T. Ichihara et al.: IEEE Trans. Nucl. Sci. NS-36, 1628
(1989).
3) N. Kruszynska: vmehb-1.2,
ftp://ftp.nikhefnl/pub/projects/vmehb.
4) K. Yoshida: private communications.
5) S. N. Nakamura and M. Iwasaki: RIKEN Accel. Prog.
Rep. 30, 152 (1997).
6) Y. Tanaka et al.: k2915_v2.00,
http://www.elc.nias.ac.jp/~daq/software/k2915.

159

RIKEN Accel. Prog. Rep. 32 (1999)

Improvement of Polarized 3He Target
T. Uesaka, s. Yamamoto, T. Wakui, H. Sakai, and Y. Yano
The RIKEN spin-exchange-type polarized 3He target was applied to a nuclear physics experiment for
the first time in 1996. 1 ) At that time the fraction ofpolarization was about 12%. Such a small fraction ofpolarization was due to a loss of pumping-laser lightat the surface of target cell. Because transmission of
the laser light through the glass surface decreases with
the incident angle, the cell should have a small curvature in order to achieve an efficient optical pumping.
The target cell which was used in the experiment had
a cigar shape of 15 mm radius.
Recently we therefore introduced a double-cell
design 2 ) to ease the difficulty. A schematic view of
the cell is shown in Fig. 1. Target and pumping cells
are connected with a 8 mmet> glass tube. The pumping
cell has a fiat surface to where the laser light is incident. The old cell design which was used in the priorexperiment is shown with broken line in Fig 1.

We have measured the 3He polarization enclosed in
the cell. Density of 3He gas was 8.9 x 10 19 cm- 3. The
result of measurement is plotted in Fig. 2. The horizontal axis is the amplitude of NMR signal which is
proportional to the 3He polarization. To obtain theabsolute value of polarization, calibration by a proton
NMR method is necessary. Though we have not yet
carried out the calibration for the present cell, a roughestimation can be done on the basis of the calibration
made for the old cell. Here we took the difference ofthe cell size into account and neglected the differenceof the cell shape. The 3He polarization thus estimatedat equibrillium is thus estimated to be 40-50%.
600

500

·a-'
400
.c

•

•

;:l

I-

~
~

300

:3
CIl

N

.J::
CIl

200

'0

P..

TARGET CELL
SOmm
10

15

20

25

30

Time [hours]

PUMPING CELL

...

_

FLAT
SURFACE

_

(

-:.)

Fig. 2. The results of polarization measurement. Solidline represents the fitting.

..

References
Fig. 1. Schematic view of the new cell.

1601) T. Uesaka et al.: RlKEN Accel. Prog. Rep. 30, 139(1997).
2) H. Middleton et al.: AlP Conf. Proc. 293, 244 (1993).

RIKEN Accel. Prog. Rep . 32 (1999)

Construction of a New Low...;Energy Deuteron .P olarimeter
T. Uesaka, H. Okamura, Y. Satou, T. Ohnishi, K. Sekiguchi, K. Yakou, S. Sakoda,
N. Sakamoto, T. Wakasa, K. S. Itoh, K. Suda, and H. Sakai
Since the polarized deuteron ion source began toprovide the beams at RARF in 1992, our group hasconcentrated in experiments with a 270-MeV polarized
deuteron beam. Therefore, a high-energy deuteron polarimeter which was constructed in the beam delivery
room has been calibrated only at Ed = 270 MeV. The
vector and tensor analyzing powers were determined as~Ay/Ay rv 1% and ~Ayy/Ayy rv 2%, respectively. Recently, however, polarized deuteron beam at the otherenergies (i.e., Ed = 140 and 200 MeV) came to be indemand, and the high-energy polarimeter have to becalibrated at these lower energies with a precision as
high as at Ed = 270 MeV.
Because there are no standard polarimetry for high-energy deuteron, the high-energy polarimeter has tobe calibrated by using a polarized deuteron beam
whose polarization is determined prior to the accel.e ration in Ring cyclotron. In the low energy region(Ed < 15 MeV), the 3He(J:p)4He reaction is known
to be a well-established polarimetry for deuteron. 1,2)
Both vector and tensor analyzing powers have been
determined with a statistical precision of 1 %.
We have constructed a new low-energy deuteron polarimeter at the C03 beam-line in the AVF-Cyclotronroom.
The schematic view of the polarimeter is
Two sets of detectors, 0° andshownin Fig. 1.
backward-angle detectors, were used to measure thetensor and vector analyzing powers, respectively.
lOOmm

2 plastic scintilla tors

ZnS

SSD collimator
Fig. 1. Schematic view of the new low-energy deuteron polarimeter.

At 0°, two 1 mm- thick plastic scintillators wereplaced downstream from the beam stopper. Because ofa large positive Q-value ( 18.4 MeV) of the 3He( d, p )4He
reaction, the incident beam and any other reaction
product can be stopped in the beam stopper or anenergy degrader placed in front of the detectors, andonly protons from the 3He(d,p)4He reaction reaches tothe detector.
At backward angles, two 0.5 mm-thick silicon detectors were used to detect protons. In the both casesof 0° and backward angles, hardware discrimination of
the 3He(d,p)4He event was successful, and no software
gate was used to obtain the beam polarization.

The first measurement was carried out by using a
8-MeV polarized deuteron beam. The target density
was 2.7xl019 cm- 3. Typical counting rate was about
1 kcps and 25 cps for 0° and backward angles, respectively, when the beam intensity was rv350 nA. The
vector and tensor polarizations were determined withstatistical errors of 1% and 0.7%, respectively, in aneight-minute measurement.
References
1) W. Griiebler et al.: Nucl. lnstrum. Methods Phys. Res.
203, 235 (1982).
2) N. Nishimori : Kyushu University, Ph. D. thesis (1996).

161

RIKEN Accel. Prog. Rep. 32 (1999)

Beam Calibration of Heavy Ion Telescopeon Board MIDORI Satellite
H. Miyasaka, T. Kohno, T. Goka, and H. Matsumoto
The satellite MIDORI was launched by NASDA for
the Earth observation. A Heavy Ion Telescope (HIT)
was on board this satellite to observe the galactic cosmic rays and the geomagnetically trapped particles. I)
Geometric factor of HIT is ",25 cm 2 ·sr and observableenergy range is e.g. 18-53 MeV/nucleon for oxygen.
The 40 Ar beam with energy of 95 MeV/nucleon wasirradiated to examine the particle identification abilityof the HIT. Figure 1 shows the configuration of thisbeam test with cross sectional view of telescope. As
Fig. 1 shows, HIT consists of two position sensitive detectors (PSD) and four pin type detectors. The PSD
has 62 mm x 62 mm effective area with 0.4 mm thickness and the pin type detectors has 85 mm diametercircular effective area and 0.5 mm thickness. The telescope is optically shielded by 0.1 mm aluminum foil.
A collimator was placed in front of the telescope. The
collimator has 5 mm thickness of brass with 13 x 13
grid of nallow holes at 5 mm interval.
Figure. 2 shows the histogram of atomic number resolution obtained by tlE-E method. The mean charge
is 17.9 and resolution is 0.66 (FWHM). This result
demonstrate the satisfactory performance of HIT.
We examined the distortion of PSD with this collimator. Center panel of Fig. 3 shows the distortionof PSD 1. The circles represent the locations of holes

Collimator

AI

PSD1

PSD2

PIN1 -2,..-'"-.

90°

~

E

¢

E
o

40 Ar

ui
co

95 MeV/nucleon

1
y

30
20
10

E
.5
><

0
- 10
-20
-30

-30 -20 - 10

0

10

20

X (mm)

Fig. 3. Position distribution of PSDl. The vector represent the distortion of observed position. Mean deviation
lengths projected at X and Y-axis are also shown withfitting curves.
of collimator and arrows represent the difference between observed position and position of the hole of thecollimator. Cross marks at right and bottom panel ofFig. 3 shows the mean deviation length projected at
Y-axis and X-axis respectively. Fitting curves of deviation length are also shown with solid lines. Using thisfitting curve, we can correct this PSD distortion.
From two PSD position information, we determine
the particle incidence angle. Figure 4 shows the distribution of observed particle incidence angle in thetilted beam measurement at 20° (top) and 35° (bottom). The broken lines represent the non-corrected
results and solid lines represent the corrected results.
Mean angle of each corrected case is 20.1° and 34.5°
and the FWHM is 0.9° and 1.3° respectively.

I

'.

I

: '1 8 Dmm: 13,Omm :62 .0mm]g:;

Fig. 1. Cross sectional view of the telescope and the beamarrangement.

20 degree

'~

100
'

'0

.

....

'~

Q)

.D

§

20 0

Z

600

30

~~~--~~~--~~~--~~~--~°°

35 degree

j

.IlL
10

20

:10

40

50

Incident angle (degree)

500

Fig. 4. Histogram of observed incident angle for 20° (top)and 35° (bottom). Solid lines and broken lines represent corrected and non-corrected for PSD distortion
respecti vely.

400
300
200
100

)

o '-----'----'---~~~
10

11

12

13

14

15 16 17 18
atomic No,

19

20

21

Fig. 2. The atomic number histogram.
162

22

23

References
1) T. Kohno et al.: Proc. 25th Int . Cosmic Ray Conf. 2,
317 (1997).

RIKEN Accel. Prog. Rep . 32 (1999)

Calibration Test of Dose Monitor on Board the ADEOS-II
Y. Kimoto, H. Matsumoto, T. Goka, T. Kohno, S. Badono, Y. Ushio, and M. Kobayashi
Calibration test of a radiation monitor for spacecraft
was done. By the calibration test, most of the functionof detectors and of the signal circuit of radiation monitor were confirmed. This radiation monitor named
dose monitor (DOM) on board the ADEOS-II will belaunched by NASDA into a sun synchronous orbit at
800 km with an inclination of 98 degree in the year
2000. The DOM measures the energy spectrum of theelectron, proton, alpha particle and of the heavy ionsheavier than Li. The sensor of DOM consists of seven
PIN-type detectors (PINs) and an anti-coincidence detector (ANTI). The telescope is optically shielded by
0.1 mm thick aluminum foil. The nuclide is discriminated by ~E- E method. The discrimination data weretranslated as telemetry data.
The H2 beam with energy of 70 MeV jnucleon wasirradiated in order to confirm the function of the sensor and electronics. Figure 1 shows the configuration
used for the beam test and shows the cross sectionalview of DOM. In this test, the output of each detector
was obtained. The beam was irradiated to the aluminum shields with various thicknesses from the frontof DOM. Various thicknesses were 0, 9.5, 11.0, 13.0,
15.0, 16.5 and 18.5 mm. The beam size was made as
small as possible. The electronics parts were shielded.
DOM is expected to be exposed to about 4.22 x 103
rad(Si) for three years in this orbit.

Fig. 1. The configuration of the beam test and DOM.

Figure 2 shows the simulated-pulse height distribution of each PIN detector observed by the pulse height
analyzer. The thickness of aluminum shield was mm.
Most of the peak voltages of each PIN were consistent
with the expectation values. Some PIN data showed
two peaks because it detected two particles incident into the detector at the same time. Figure 3 shows thepulse height distribution for the case of AI-thickness of
9.5 mm. Some peaks in each PIN were consistent withthe expectation values, but some were not.
Then, the experiment and expectation values foreach shields were compared. Figures 4 and 5 show thePINI & PIN3 deposition energy peak values of the experiment and expectation for each shield. From thesecharts, the experimental data are found to correspondto the expectation values except for thick shields. In
the PINs and ANTI, some detectors had good corre-

204E
25824ct

°

•

PINl

15279ct, ; ,6246ct

PINS

I ~ I II~~:'~' :A1.44V
2. 25V~~---PIN-2--j.!:~~~~¥8v~·' ==------PI-N-6---1

204S

14065ct 5106ct,1749,?ct 7124ct~~~~--~~~:~~'~~:-'~'----~~~,~j~~~: ~;~.:~---------~' '1.31V 2.70V

8 2048
=:I

3 .2V
6.04V
13907ct l0144ct

PIN3

e : t~ : ~ :204E~' 1.4V 2.78V
13653ct,~ : 8016ct:;, :j\ :
0: '

.

PIN4

PIN7

,13857ct;: :4,921ct,A : A: 1.49V

O.74V
13847ct 5001ct
rIt\

1023 0

I

:!~
1.97V

I

:

ANTI

II

I I

3.97V

11323

O.71V 1.59V

ChannelFig. 2. The pulse height distribution from each PIN detector (Shield = 0 mm).

163

25€

: 5446ct

PIN 128711<'

2953ct

•

I

,

,

~~;.;

~

'2.2V 3.41V

25€

PINS

PIN2

1.2i~

PIN6

2185ct 3300ct

5407ct,I,~!::. .. • Experiment[MeVl - 0. - Expectation[Mevl l, 6.02V

24~V '3.04V

PIN3

:>

15

Q)

~

~10

:;~~;
5593ct

I-..

I

PIN?

Qi

c:
Q)

3581ct 1806ct

I

':111

~

j:\ '
2.02"'; '2.56V

PIN4

ANTI

3245ct ,) 2193ct

o:.r~\ :

1023 01023

4.24 "; 4.66V

Channel

o

5

'0

15

20

Shield[mm)Fig. 3. The count data from each PIN (Shield = 9.5 mm).

Fig. 5. The experimental and expectation values of deposition energy peak versus shield thickness (PIN3).

1---1:>--- Experiment[MeVl - 0 - ExpectatiOn[Mevl !

:>

2

Q)

~1 . 5
Cl

«i

c:
Q)

c:

~

.~ 0.5
0.
Q)

o

o

o

5

10

15

20

Shield[mmlFig. 4. The experimental and expectation values of deposition energy peak versus shield thickness (PIN1).

164

spondence between the experiment and expectation,others did not. When the outputs of the preamp wereanalyzed after the experiment, it was found that thisdisagreement was caused by the interference from otherdetectors. The configurations of the lines and circuits
were rearranged. Each crosstalk was thus improved after that which was confirmed by electronic pulse test.
In electronic pulse test, pulses with different energies
were simulated. Then the output of the energy deposition was confirmed too. The leak current of theeach PIN detectors was measured. There was no difference between the peak currents before and after theirradiation experiment.

RIKEN Accel. Prog. Rep. 32 (1999)

Performance Study of the Plastic Scintillator for BESS Experimentwith Heavy-Ion Beams
H. Fuke, T. Kaneko, A. Matsuda, Y. Yamamoto, K. Yoshimura, and H. Sakurai
BESS (Balloon-borne Experiment with a Superconducting Magnet Spectrometer)l) has been performed
since 1993 in order to measure the precise energy spectrum of cosmic-ray particles. Figure 1 shows the crosssectional view of the BESS spectrometer. It has a large
acceptance (0.3 m 2 Sr.) and a wide energy range (0.2100 Ge V). Most of scientific data were collected at altitudes of about 36 km during the balloon flights overthe northern Canada.
PRESSURE VESSEL

units : mm
R756

Fig. 1. BESS spectrometer. The dotted line shows where
the new counter will be placed.
It is important to measure fluxes of cosmic heavyions (3-6 :S Z :S 30) for determination of the cosmicray propagation mechanism. It is also of interest to
search for cosmic strange matters. 2 ) The present BESS~! range is, however, specialized in the 1 :S Z :S 8
region. Therefore, a prototype of a new plastic scintillation counter to use on board the BESS has beendeveloped and tested with RIPS produced heavy-ion
beam. In this report we present data for the luminescent response of the plastic scintillator to heavy ions.
Figure 2 shows an overview diagram of the plastic
scintillation counter, where the counter consists of alarge diffusion box made from aluminium. It contains
plastic scintillator (BC408) viewed by eight 2-inch diameter fine-mesh PMTs at the both ends. The surfaceof the inner side is covered with a reflector (Goretex).
The dotted line in Fig. 1 shows where the new counter
will be placed in the BESS spectrometer. The following are the characteristics of the counter.
(1) Thin plastic scintillator: 3 mm thick(2) Large sensitive area; but light in weight(3) Good uniformity(4) Good energy response resolution(5) Wide range in charge state (3 :S Z ~ 30) by one
single setup before PMTs' saturation.
(6) The counter should operate in the fringe magnetic
field of "-'0.2 T when the counter is incorpolated
into the BESS spectrometer. The angle between
PMT axes and the horizontal axis is not zero but
finite.
The experiment was carried out using RIKEN
Projectile-fragment Separator (RIPS). The beam was
obtained from the fragmentation of 58Ni projectiles at
90 MeV/nucleon on a Beryllium target, by selecting
the emission angle and momentum. The beam was detected by a 0.5 mm thick silicon detector and a 0.5 mm
thick plastic scintillator (PL) located at the final focal
plane (F3) of RIPS. The magnetic rigidity of RIPS was
set to be 2.4 or 2.6 Tm. The particle-identification of
the fragments was carried out event-by-event by meansof measurement of time-of-flight (TOF) and energy deposit (6.E). The TOF of fragments between the production target and F3 was obtained from the PL timing and RF signal of the cyclotron. The 6.E of heavy
ion was obtained from the silicon detector.
Figure 3 shows four data points where the beam wasspotted.
Figure 4 shows a scatter plot of the light signal fromour scintillator versus 6.E of the silicon detector, eachin units of minimum ionization. The response resolu-

Plas /lc SCln/llla/or(8[4 0 8 3mm)

Beam.: spqt
size$1cm

beam test

R7 12

Fig. 2. Overview of the plastic scintillation counter.

Fig. 3. Locations where the beam was spotted.
165

F = ! In( 2m e c2 jJ2,2 ITo) - {32
2 In(2mec2 (32,2 11) - jJ2 'Sci nti VS Silicon...o

Jg 2000:g 1750'(3

en 1500
1250

1000
750
500

250
o ~~~~~~~~~~

o 50010001500200025003000
SiliconFig. 4. Scatter plot of scintillator light output vs. silicon~E.

tion of the scintillator is better than 4% for the particles which passed through the plastic, which is similar
to the resolution of the silicon detector.
Again in Fig. 4, the light signal from the scintillator was calculated as a simple sum of 8-PMTs' signals.
This value shows the following relationship among different beam spots in Fig. 3, which is independent ofdEdx'

M : N : P : Q = 1.067 : 1.078 : 1.000 : 1.015(1)Thus, the counter has a small un-uniformity of lessthan 4%.
.
In recent years, a number of considerable works havebeen done to understand the scintillation response,
which is a function of the incident particle's energy,
charge, and mass. The complex response, however,poses a challenge in their calibration. Birks 3 ) proposed a simple expression which took into account thequenching of the light output for the cases of very large
energy loss. Meyer and Murray 4} suggested a model
which also took high energy electrons into account, or"delta rays," which escape from the primary inonization column (MM-model). Here, we present an interpretation of the scintillator response data based on the
MM-model. In this model, the differential light output~~ arises from the two sources:(1) A primary column of ionization centred along thepath of the incident particle.
(2) Energetic secondary electrons which escape theprimary column.
The scintillation efficiency in the primary column
is taken to be a saturation function of ~~ such as theBirks' formula (~~ < 1), while delta rays produce lightwith high efficiency (~~ ~ 1). If F represents the fraction of the energy carried away by delta rays, then the
differential light output may be expressed as

dL
dx
166

S(l - F)dE

_ _ _ _--=d=x-:-;::::-

l+(l-F)kB~~

dE
+ SF-

dx'

(2)

(3)

where {3 and, are calculated from the velocity of theincident particle, me is the electron rest mass, I is theionization potential of the scintillator, and To is theminimum electron energy needed to escape from theprimary column.
Thus, there are three parameters in this expression:
the scintillation constant S, the quenching factor kB,
and the electron kinetic energy cutoff To. We fitted these 3 parameters to the data with the X2 minimization technique, and obtained the following values:
kB = 12 mg/cm 2 MeV, To = 3.8 keV, and residual
errors ::; 1% for Z ~ 4 particles (S depents on the device).
Figure 5 shows the predicted (doughnut marks) andmeasured (filled circles) peak values of some nuclei.
The horizontal and vertical axes show the theoreticaltlE and the light output data, each in units of minimum ionization. It is obvious that the scintillation
light output is not a simple single-variable function oftlE but a two-variable function of {3 and charge state
Z, which we succeeded in describing precisely.
Although the above mentioned analysis is not yet
final, it can be concluded that our plastic scintillation
counter has a good response resolution (::; 4%) and asmall un-uniformity (:S 4%). In addition, we could reproduce the data by a model which takes both quenching and delta-ray effects into account.
Response dependence on Z,fj

c:
:[140
><

:3 120/Ornodel dUdx / '.
=d: E/d~/ :

"0

':

':

/

60

.... _/

40

/

~=0.9

da~a
.
~=0.6
.

, ... - fj:O.3~

13-0.2~ ).~" .. p=O.'

o~~~~~~~~o50 100 150 200 250 300

dE/dx (mip)Fig. 5. The result of 3-parameters fitting. The scintillation
light output is a two-variable function of (3 and charge
state Z , and the fit can reproduce it precisely.

References
1) S. Orito et al.: Phys. Rev . Lett. 75 , 3792 (1995); Phys .
Lett . B 422 , 319 (1998); Phys. Rev. Lett. 81, 4052
(1998).
2) T. Saito et al.: Phys. Rev. Lett. 65 , 2094 (1990) .
3) J. B. Birks: Proc. Phys. Soc. A. 64 , 874 (1951).
4) A. Meyer et al.: Phys. Rev. 122 , 815 (1961).

RIKEN Accel. Prog. Rep. 32 (1999)

Construction of a Liquid Hydrogen Target
H. Akiyoshi, K. Sagara, and T. Motobayashi
A liquid hydrogen target for the experiments withsecondary beam has been designed and is currently under construction. The design has been made to meetthe following requirements. The thickness of hydrogen is typically 100 mg/ cm 2 . The ratio of hydrogento other materials should be by far larger than thatof polyethylene foil which is a typical hydrogen target. The target system should be easy to mount anddismount.
Figure 1 shows a schematic view of the liquid hydrogen target. The target cell is attached to the cold-headthrough a copper-rod. The target cell is connected toa gas reservoir with a thin stainless steel pipe. The
volume of the reservoir is 10 f. The cryogenic refrigerator cools hydrogen gas in the target cell down toabout 20 K, and liquefies it. The hydrogen gas issealed in the closed system, so the gas pressure decreases steeply when the hydrogen is liquefied. The gaspressure is measured by a pressure transducer . Temperature of the target cell is measured by a Si diodethermometer. Another Si diode thermometer is attached on the copper-rod (see Fig. 1) . Excitation current for the Si diode thermometers is supplied by battery powered current sources. The room-temperatureis measured by a thermocouple on the reservoir. A
heater is mounted on the copper-rod. The temperature is controlled by changing the power to heater.
The target cell, the copper-rod, and the cold-headare surrounded by an aluminum heat shield at the temperature of about 80 K. The shield has two 25 mm
diameter holes for the beam entrance and exit. The
target can be lifted up by 10 cm, so that one can use
other foil targets.
Figure 2 shows a cross section of the target cell. The
window foils are made of 12.5 J-Lm thick aramid foil.
The window foil is pressed by a foil-cover which has
a 24 mm diameter hole for beam. Due to the innergas pressure of 1500 hPa, the window foils swell out.
Thickness of the hydrogen is designed to be 14 mm.
The thickness can be changed by replacing the target
cell.
Digitized data on the data acquisition/switch unit
which is connected to the thermometers and pressuretransducer are acquired by a computer located outsideof the experimental hall. Remote control of the DC
power supply for heater is possible by the computer.
The data acquisition and the control of heater power
are made by a software on LabVIEW 1 ) which sends
GPIB commands through Ethernet.
When the output from one of the Si diode thermometers become smaller than the lower limit of temperature, an alarm system is turned on and the refrigerator is turned off. When the output from one of the Si
diode thermometers reaches beyond the higher limit,
an alarm is turned on and the heater power is turned
off. The safety system is deployed locally, so as to work
even when the computer or network downs.

Hydrogen
Gas

Cryogenic Refrigerator
Pressure Transducer

Bellows

Reservoir

VacuumAramid Foi I
lHeatefBeam

Thermometer

Target Ce II
Fig. 1. Schematic front view of the liquid hydrogen target
system.

Fig. 2. Schematic side view of the target cell cross section.

References
1) LabVIEW 5.0.1, National Instrument Corporation.

167

RIKEN Accel. Prog. Rep. 32 (1999)

High Resolution MUltiple Sampling Ionization Chamber (MUSIC)
Sensitive to Position Coordinates
H. Petrascu, H. Kumagai, 1. Tanihata, and M. Petrascu*
A new type of MUSIC sensitive to position coordinates has been developed recently. The development
is based on the theoretical analysis of Ref. 1. Thisdetector will be used in experiments on fusion to use
radioactive beams, and is suitable, due to the high resolution, for identification and tracking of low Z (downto Z = 1) particles. One of our goals, when we started
to work, was to reduce, as much as possible, the Zvalue of particles that can be "seen" by an ionizationchamber.
The resolution was improved by connecting preamplifiers directly to the MUSIC's pads. These preamplifiers are able to work in the vacuum and very low
gas pressure. In this way the value of S / N ratio wasincreased by a factor of ""10.
The detector is a Frisch grid type, with the anodesplit ted into 10 active pads. It is the first model of theionization chamber with the field shared between theposition grid and the anode pads. The Frisch grid wasnecessary because the detector is originally designed
for very accurate energy measurements and particle
identification. A drawing of this detector is shown in
Fig. 1.

the support of the 20 11m W wires spaced by 0.3 mm.
For the position grid we used 10 groups of wires madefrom Au-plated W with 20 Mm in diameter. Everygroup is composed from 5 wires spaced by 0.9 mm connected in parallel. Both Frisch grid and position grid
wires are parallel to the beam direction. The anodepads are transversal to the beam direction, and eachof them has an area of 7.8 mm x 60 mm. Every padand every group of wires from position grid is directly
connected to a charge sensitive preamplifier.
The chamber's energy resolution was first tested using a P-10 gas (Ar 90% + CH 4 10%) at the pressures
between 200-300 Torr. As a radioactive source we used
a 241 Am 0: source with an activity of 5 kBq. We usedalso a 4 mm diameter collimator for beam, located at
20 mm away from the 0: source. The drift velocity ofthe electrons in cage was selected to be 5 to 8 cm/ MS.
A typical pulse distribution in the chamber is shownin Fig. 2. When P = 250 Torr, we obtained FWHM
value of 10.4% on the 7th pad, and 8.5% on the 9th
pad. One may recognize a "Bragg curve" behavior of
the peaks over different pads.
Determination of the position resolution is inprogress.

135

L

100

'" I

"

-l-

0.1 mmCathodeCUiBe wires

.

2000

I-HV

Qj

c:

~
u

-:-

ID
Beam

•

~ ~

'C• •

-'

'!I-

~ Nr=.-

Gri .

r-

0:

It
Frame with pas rtionwire

~

1000

C
::;J
o
()

500

o

~D

~ Anode with 10 active pads

1500

~

Pre mp . l"' Connector 1
Connector 2
Preamp . 2

10

9
8

,()

7

<>'0-

6

"V">6 5 4 ..:...------"'..,------'--/
Ill,.

Fig. 1. Schematic picture of MUSIC.

3 ~-----'o,:----~---<I
2

1

The detector itself consists of four main parts. The
first one is the constant field-gradient cage, sandwichedin between the cathode and the Frisch grid. The second
is the Frisch grid. The third is the position grid locatedunder the Frisch grid. The last one is the plate withthe anode pads. The cage is 60 mm wide and is madeof 100 Mm Cu-Be wires. Every wire is tensioned withthe weight representing a half of its breaking limit. The
Frisch grid was fabricated using an aluminum frame for

Horia Halubei National Institute of Nuclear Physics and Engineering, Romania

168

100

50
Channel number

Fig. 2. Pulse distribution at P = 250 Torr. The pulse
height is near approximately 5 V.

References
1) G. D. Badhwar:(1973).

Nuel. lnstrum. Methods 109 , 119

RIKEN Accel. Prog. Rep. 32 (1999)

Fast-Neutron Measuremept Using a Scintillating Fiber Stack with
Neutron Beam From 7Li(p, n)7Be Reaction
K. Terasawa, T. Doke, J. Kikuchi, S. Takenaka, M. Yamashita, M. Kase, T. Uesaka, and T. Ohnishi
Radiation dosimetry in space is essential for astronauts in spacecraft. The measurement of radiationdose from ionizing radiation has been made by various
detectors. 1 ,2) However, contribution from the fast neutrons has not been measured well, because the neutron
dosimetry in space is not so easy as the ionizing radiation dosimetry. To evaluate neutron dose more accurately, the 3-dimensional imaging detector consistingof a scintillating fiber stack has been developed.
Generally, fast neutrons are efficiently scattered bylight nuclei. The energy of recoil nucleus is given by(1)
where, Er and En are the energies of the recoil nucleus and incident neutron, respectively; fJ is the recoil angle of the nucleus; and A the mass number of
the target nucleus. The recoil nuclei produced by thecollision with fast neutron can be identified from thepenetrating charged particles by observing the track of
the recoil nuclei appearing inside the stack. Then , therecoil nuclei and electrons produced from, rays can be
identified by observing each scintillation intensity perunit length along the track. The lower threshold energy measurable by a neutron dosimeter is determinedby the technical limit of n-, discrimiriation.
So far, it is confirmed that identification of penetrating protons and recoil protons from neutron interaction can be made easily and that lower energy limit
to identify neutrons and , rays is estimated to be 12 MeV in the scintillating fibers of 0.5 x 0.5 mm. 3 )Here, we report the energy calibration for fast neutrons
and its lower energy limit by using rv66 Me V neutron
beam produced from 7Li(p, n) 7Be reaction with proton energy of 70 MeV in the E4 beam line of RIKEN
cyclotron. Using the information on the incident direction of neutrons, the recoil angle of protons and therange of recoil protons in the stack, the relation between recoil proton energy and recoil angle given by
Eq. (1) ,was experimentally checked, and the result isshown in Fig. L Here, it was assumed that all tracks
originating from the inside of the stack were consideredas the tracks of recoil protons for simplicity. If the energy of neutrons was completely monochromatic, data
points would have been concentrated near the line of
neutron 66 MeV, within the resolution of the detector,
in Fig. 1. However, data are widely scattered below
the line because they have wide energy spectra andbecause the range of the recoil protons with higher energy is frequently over the detector size. Taking theabove conside'r ations into account, Eq. (1) can be confirmed roughly on its validity. Figure 1 depicts no data

70

Neutron 66MeV

>" 60

;

>,

./'

Expen/~"Wd~
.
/'

50

~

~

40

g

30

.

(5

.

~ 20

o
~

,~

' ..

:0-,.

10

S.~0--~0~.2--~0~.4----0~.6~--~0.8~--~l.O
COS\Recoil an Ie)

Fig. 1. Relation between recoil angle and recoil protonenergy.

below 10 MeV, because the image intensifier was triggered by coincident signals from two photomultipliers.
Therefore, no event with the range less than rvl mm
was recorded. If the image intensifier was triggered bysignals from a single photomultiplier, the recoil protons
with the energy lower than 10 MeV could be detected.
The data plotted in Fig. 1 include only recoil protons
which stopped inside the stack. In order to evaluate
the recoil protons penetrated the stack, the relation between the light yield and the light intensity per CCD
pixel is plotted in Fig. ·2. The range of the electrons
at the energy from rvl MeV to rvl0 MeV is several
teri times longer than that of proton at the same energy. The difference of the light intensity per CC'D
pixel between electrons and protons in Fig. 2 ·isconsistent with that expected from the range-energy relation. The experiment using the neutrons produced by
the D-D or D-T reaction, which is scheduled for thenear future, will clarify the response of this method in
the low energy region and will find lower energy limit
for identifying neutrons and electrons.

"I

0+.

.c::

sl

Stopping protons
Penetrating protons
137
CS

3 20

O~~~~~~~---L--~~

o

10

20

30

40

50

60

70

Light yield normalized by 137es .

Fig. 2. Light intensity per unit length along the track.

References
1) G. D. Badhwar et al.: Nucl. Tracks Radiat. Meas. 20,
13 (1992).
2) T. Doke et al.: Nucl. lnstrum. Methods Phys. Res. A
365, 524 (1995).
3) K. Terasawa et al.: loniz. Radiat. 24, 119 (1998).

RIKEN Accel. Prog. Rep. 32 (1999)

Position Sensitive Detector Using Scintillation Fiber
K. Morimoto, F. Tokanai, and M. Kurata
A Scintillating Fiber Imager (SFI)1) has been developed for the Restriction Landmark Genomic Scanning (RLGS)2) technology. The RLGS technology isa powerful and relatively rapid method for the genetic
analysis of mouse and human genome as well as thatof other animals and plants. RLGS employs a direct
end labeling of the genomic DNA digested with a restriction enzyme, high resolution two-dimensional gel
electrophoresis, and autoradiography. The restriction
enzyme site labeled with beta-emitting radionuclide of
32p can be used as landmark loci. Hereafter we callthe restriction enzyme as genome spot. There are morethan two thousand genome spots in a single dried gel of
40 x 40 cm 2. Film-based autoradiography is one of themost useful methods to obtain the genomic information, because of its large detection area and excellent
spatial resolution. However, it has two disadvantages:i.e., (1) long exposure time (about two weeks) due tothe low sensitivity, and (2) lack of quantitative information due to the non-linear response and limited dynamic range. The present system, on the other hand,offers a real time acquisition and easy quantification of
RLGS data compared to film-based autoradiography,
and it is proved to be a powerful position sensitive detector for measurements in nuclear physics . .Test measurements have been carried out with genomic linkage
map labeled with 32p (f3-ray emitter) and 58Ni beam at
90 A Me V as well. The RLGS map used in the detector
Projection X

1~~
50

100

150

test was processed at the Genomic Science Laboratory
of RIKEN. The map was electrophoresised to two dimensional and dried on filter paper. We carried out theobservation of the genome spots labeled with 32p one
day after the RLGS process. Figure 1 shows the imageof genome spots in a single dried gel sheet. The genomic spots are clearly seen and each one can be distinguished. It took about 50 h to accumulate the statistics applicable to quantitative analysis. This showsthat SFI shall need much shorter time to measure the
RLGS map compared to the film-based autoradiography, since the autoradiography takes about two weeks
to obtain the image.
However, the detection efficiency was smaller than
expected (roughly 12 h). This lack of detection effi-

PPAC

B2

Bl
-

Scintillator
for beam trigger

SF!

-

Focus of beam

106 em51.5 em••Fig. 2. Layout of detectors in 58Ni beam measurement.
PPAC is the position sensitive Parallel Plate Avalanche
Counter. B1 and B2 are plastic scintillation beam counters.

(mm)

The anode output of irradiated fiber

o

100

200
300
400
500
pulse height (ADC Channel)

600

700

10000l The anOd~ut of neighboring chan nel

1I~~~t=::\oFig. 1. Image of RLGS map labeled with 32p. The genome
spots are clearly seen.

170

100

200
300
400
500
pulse h e ight (ADC Channel)

:
1

600

700

Fig. 3. Pulse height spectra of 58Ni beam: (a) Spectrumof output from the anode watching the irradiated fiber.
(b) Spectrum from the anode watching the neighboring
fiber.

ciency could be explained by the cross-talk of scintillating photons at joining points between the fibers
and the photo-cathode of Multi Anode Photo Multiplier Tube (MAPMT), since the anode pitch of thisMAPMT is too narrow to collect all of the photons
emitted by corresponding fibers. In order to investigate a detection efficiency of SFI and a cross talkbetween fibers and the photo-cathode of MAPMT, we
carried out a test measurement with the heavy ionsproduced by the RIKEN Ring Cyclotron. The incident beam was 58Ni at 90 A Me V of energy. The
layout of the detectors is illustrated in Fig. 2. Figure 3(a) shows an example of pulse height distribution
obtained with one anode watching the irradiated fiber,where the highest pulse is selected in all anodes for one
beam event. Then, Fig. 3(b) shows the pulse height

distribution of output from the anode watching theneighboring fiber at the same event. We found that40- 50% the scintillated photons from the edge of thefiber were collected by neighbors. If we could avoid
this cross-talk, the detection efficiency for the RLGS
map would increase. The detection efficiency of SFI
is 70% of the beam trigger. The main reason of the
reduced detection efficiency is due to the 74% effective
area of SFI against the beam of vertical incidence. We
have shown that the SFI is applicable to not only the/3-ray but also heavy-ion detections.
References
1) K. Morimoto et al.: RIKEN Accel. Prog. Rep. 31, 163(1998).
2) Y. Hayashizaki et al.: Genet. Soc. Am. 138, 120 (1994).

171

RIKEN Accel. Prog. Rep. 32 (1999)

Measurement of the Energy of Heavy Ions at Around
100 MeV/nucleon with Allene-Doped Liquid
Argon Ionization Chamber
A. Yunoki, T. Doke, M. Kase, T. Kato, J. Kikuchi, K. Masuda,*l M. G. Niimura,
K. Ozaki,*2 E. Shibamura,*3 M. Tanaka,*2 and I. Tanihata
An allene-doped liquid argon ionization chamberwith 48 mm x 48 mm x 40 mm sensitive volume has
been constructed for precise energy measurement ofheavy ions at around 100 MeV/nucleon. The energy
resolution of 0.6% (FWHM) was achieved for 40Ca ionsat 94 MeV /nucleon. 1,2) We expected that a better energy resolution would be obtained for lighter ions suchas 0 and Ne because Hitachi and coworkers obtained
better energy resolution for 16 0 ions than that for 36 Ar
ions at around 30 MeV /nucleon. 3)
The detector system was the same as that used in
the experiment with 40Ca ions. Allene concentration
into liquid argon (LAr) was 10, 20, and 80 ppm.
Energy resolution of the gridded ionization chamber was investigated with 0 (.) and Ne (., a) ions ataround 100 MeV/nucleon. Figure 1 shows the fractionof collected charge Q/Qo as a function of an external
electric field (E). The Q/Qo was obtained from the collected charge (Q) divided by the total ionization yield(Qo), which was given from the total absorbed energy
in the LAr divided by the W-value in LAr. The maximum value of Q/Qo was 40% which was obtained under E = 4 kV /cm for 16 0 ions at 133 MeV/nucleon in
20 ppm allene-doped LAr. Figure 2 shows the energy
resolution as a function of the E. The energy resolution was obtained by subtracting in quadrature thewidth of test pulses from that of the charge signal anddividing it by the peak channel of the charge signal.
The best energy resolution in Fig. 2 is 1.1% (FWHM)
under E = 1 kV/cm for 20Ne at 133 MeV/nucleon
in 10 ppm allene-doped LAr. The energy resolution
was improved as E was increased from 0.5 kV /cm to
1 k V / cm, and was degrading as E was increased from

1.5 to 4 kV /cm. Figure 3 shows the energy resolution as a function of the beam intensity under E =1.5 kV /cm, which includes the energy resolution for
40 Ar at 94 MeV/nucleon (.). The energy resolution
started degrading as the beam intensity increases.
Contribution of the fluctuation of energy loss in thematerial existing upstream of the chamber to the energy resolution was estimated to be 0.2% (FWHM).
The experimental result was worse than this estimation by a factor of 5. The reason why the energy resolution would not improve with increase of the external
electric field is not understood yet. The degradationof the energy resolution may be due to the variationof the Q/Qo made by positive ions left in the sensitive
volume of the chamber. Based on a simple model, an
additional electric field is estimated to be an order of
1 kV /cm for a beam intensity of 100 cps.

100.1
External electric field [kV/cm]

Fig. 2. Energy resolution as a function of the E.

10
100
1000
Beam intensity [particle/s]

External electric field [kV/cm]

Fig. 1. Fraction of charge collection (Q/Qo) as a functionof the E. Symbols of (.), (.) and (.) represent the dataof 10, 20, and 80 ppm, respectively.

Fig. 3. Energy resolution as a function of the beam intensity at E = 1.5 kV/cm. Symbols of (.) represent thedata of 40 Ar ions in 80 ppm allene-doped LAr.
References
1) A. Yunoki et al.: RlKEN Accel. Prog. Rep. 30, 148(1997).

*1
*2
*3

172

Solar-Terrestrial Environment Laboratory, Nagoya U niversity
Advanced Research Institute for Science and Engineering,
Waseda University
Saitama College of Health

2) A. Yunoki et al.: to be published in Nucl. lnstrum.
Methods Phys. Res. A.
3) A. Hitachi et al.: Nucl. lnstrum. Methods Phys. Res. A
340, 546 (1994).

RIKEN Accel. Prog. Rep. 32 (1999)

Multiwire Proportional Chamber Read-Out System for Pulsed
Muon Facilities
S. N. Nakamura, Y. Matsuda, K. Ishida, T. Matsuzaki, K. Nagamine, D. Tomono,* and M. Iwasaki
Multiwire Proportional Chamber (MWPC) is a gas
chamber with thin wires on which high voltage applied
to. It provides us a good spatial resolution (determinedby a wire pitch, typically ",2 mm) of the particle tracks
as well as a good timing resolution (",10 ns).
With its spatial and timing resolution, it can serve
for many applications at a pulsed muon facility. For
example:• precise measurement of muon lifetime,• test of the exponential decay law,
• muon tomography, and• advanced J.LSR experiments.
However, conventional MWPCs are designed forcontinuous beam facility or for pulsed beam facility
to study short-life particles. They are not suitable atpulsed muon facilities where the time structure of signals is quite unique. Emission of the e± from J.L± decay
distributes upto several 10 J.Ls (TJ-L = 2.2 J.Ls), and signal rate is quite high (2 x 103 /100 ns/total solid angle",20 CHz/total solid angle at the RIKEN-RAL Muon
Facility) just after a burst of muon beam. Therefore,dead time of read-out system of conventional MWPC
is too long to use at pulsed muon beam facilities. We
have been developing a MWPC system with multi-hit
capability, which can be used at a pulsed beam facility
such as the RIKEN-RAL Muon Facility. 1)
We have fabricated two sets of MWPCs (C1 and C2)
with 320 mm x 320 mm effective area. Each MWPC
had X and Y planes and each plane consisted of 160
anode wires (gold plated tungsten of 20 J.Lm diameter)with 2 mm spacing. Each wire planes were separated
by the cathode planes made of aluminized mylar sheet(12 J.Lm thick) and the distance between anode wires
and cathode plane was 4 mm. Typical operational voltage was -3 kV.
Two types of gases (Magic Cas, Ar + Ethane 50/50)
were tested. Magic Cas (Ar, Freon, and Isobutane gas
mixture) allowed a higher operational voltage and ahigher gain output. However, a change of gas mixture
leads to an efficiency drift, and thus the gas mixture
should be carefully controlled. On the contrary, thegas mixture control was not required for Ar + Ethane
50/50 gas, which was pre-mixed at a factory, but it
gives a smaller gain output and a slightly poorer time
resolution. Now, we are testing both gases and further
study is in progress.
Figure 1 shows a schematic diagram of MWPC readout circuit. The induced charge at each wire was preamplified and transferred to the amp-discriminator,
where the signals were shaped and converted to belogic signals.
Department of Physics, Tokyo Institute of Technology

Pre-Amps

ex plane)

32 chlmodule

11~~UU ~ a

I II~
Mwre

Pre-Amps (Y plane)

10 MHzDiscriminator

32 cblmodulet

GPS ClockFig. 1. Schematic diagram of the MWPC read-out circuit.

Two types of time to digital converters (TDC) have
served to obtain position and timing information from
the MWPC. The first one is used to receive fired-wires
information from a particle passed position, and theother is for very precise timing experiments. The firstone should have small least-significant bit (LSB, ortime binning) to select simultaneous hits on X andY wires which give particle hit positions. However,excellent integral and differential linearities are notrequired. We adopted LeCroy long-range multi-hit
CAMAC-TDC 3377 for this purpose. It has 16 multihit capability and 32 J.LS time range with 500 ps LSB.
Each module contains 32 channel and we will use 20
modules of them.
One the contrary, some experiments require very
accurate time information (e.g., J.L+ lifetime measurement), and TDC3377 cannot serve for this purpose. In this case, very accurate integral and differential linearities are essential, but modest LSB (50100 ns) is enough. We are developing latching memory
with global positioning system (CPS) for this purpose(Fig. 2).
.
The CPS receiver (Hewlett Packard HP58503A) has
a very accurate quartz clock, and furthermore it is continuously calibrated by atomic clocks (10- 12 accuracy)
on CPS satellites. The latching memory records thewire information (fired or not-fired) at the timing ofsampling clock which is provided by the CPS frequency
receiver. Therefore, integral and differentiallinearities
are expected to be extremely good. One module accumulated 48-wires information to 2048 samples. The
external clock was 10 MHz, and thus the time window
was able to open up to 200 J.LS.
Overall accuracy of our clock system is better than",20 ps (r.m.s.) which is restricted by an instability ofthe discriminator rather by than the accuracy of the
CPS clock itself.
The MWPCs have 640 wires in total and each of173

Latching Memory (RPC.28l)

Wire Information
MWPC Wire Information
ECL signals from
Amp·Discriminator (RPV·020)

Clock

1 0000001000 ...0000
0001000000 ... 0000
0000000000 ... 0 100

48 wires2048 0000000000 ... 0000
CAMAC Bus

10 MHzGPS Frequency Referenc
Receiver HP·58503A

Fig. 2. MWPC wire information is sampled by a latchingmemory at the timing of an external clock provided by
the GPS frequency reference receiver.
them provides 1 bit of information (hit or no-hit) inevery 100 ns for 100 J.LS. Therefore, we have 80 kB datain every 20 ms (4 MB / s) and it is not trivial to read
all the data without a serious dead time. A CAMAC
block read-action takes typically 1.5 J.Ls/16 bits andhence rv60 ms is necessary for just reading all the wire
information. Therefore, we have divided the latchingmemory modules into four CAMAC crates and eachequipped with an Auxiliary Crate Controller (ACC),
Kinetics Model K3976, which was a single-board computer with MC68030 CPU (40 MHz) and 1 MB memory. The basic concept of the data acquisition system
was already reported in another paper. 2) We used fourof such system in parallel. Figure 3 shows schematically the data acquisition system.
Signals from C1-X, C1-Y, C2-X, and C2-Y planesof MWPCs were distributed to four CAMAC crates,and each CAMAC crate contained the latchingmemory modules which recorded the wire information.
The ACC read and compressed the recorded data. After closing the time window, the trigger logic issued atrigger signal to one CAMAC crate (named the main
crate) and it provided trigger signals to the other ones.
Receiving the trigger signal, the ACC started to collect the wire information from the latching memory
modules and compressed data to store in its memory.
When the memory of the ACC became full, it transfered data to a host computer for the on-line analysis
and data storage. In order to associate recorded data
separately in different CAMAC modules, the main
crate issued an event identifier (14 bits digit = 016383) to the other three CAMAC crates at every trigger. Therefore , the data which belonged to the sametime-window had the same event identifier even though
they were recorded in different CAMAC crates and in
host computers. The event identifier was an unique
number in the last 5.5 minutes acquired data at therepetition rate of ISIS. Thus we were able to gather
separately accumulated data without a confusion in
the off-line analysis.
We have developed a multiwire proportional chamber system for pulsed muon beam facilities. It was
equipped with an excellent integral and differential linearity clock system. In order to handle a large amountof data from MWPC system, we have also developed
a parallel CAMAC data acquisition system.
The system is being checked with a test beam at
port 3 of the RIKEN-RAL Muon Facility (Fig. 4).
The system will be used for the measurement of the
precise J.L+ lifetime and for the test of the exponential
decay law which will start in early 1999.

105

10 4

GPS External Clock (10 ·12 accuracy)

[/J

+>

I=:

Data Acquisition Trigger

;:J

103

MWPC with LM+CPS

0
U
10 2

10 1

100

0

10000

20000

30000

40000

Time (ns)Fig. 4. Time spectra of 11+ decays. The time spectrum measured by a plastic counter with LeCroy TDC(20 ns/bin) has a large distortion at t
0 due to a
count loss, while such a problem cannot be seen for thetime spectrum measured by the present MWPC withlatching memory + GPS clock system (100 ns/bin).
I'V

References
1) K. Nagamine et al.: Hyperfine Interact. 101/102 , 521(1996).

Fig. 3. Configuration of the data acquisition system.
1742) S. N. Nakamura and M. Iwasaki: Nucl . Instrum. Methods Phys. Res. A 388, 220 (1997).

6. Material Analysis

RIKEN Accel. Prog. Rep. 32 (1999)

Chemical Shift Measurements of K Q1,2 Lines Using
an In-Air High-Resolution PIXE System
K. Maeda, A. Tonomura, H. Hamanaka, * and K. Hasegawa *High-resolution PIXE (particle induced X-ray emission) spectroscopy using crystal spectrometers is quite
suitable for investigation of the chemical environments
of atoms in small amounts of target materials. Recently we have developed a compact crystal spectrometer equipped with a position-sensitive proportionalcounter (PSPC) for high-resolution PIXE analysis in
atmospheric air. I ) Utility of this spectrometer system
for in situ chemical state analysis was demonstrated
by measuring fine structures in K (3 spectra of third
period elements. 2)
Although the chemical effects reflected on K Q spectra are not so prominent as those on the K {3 spectra,
the production cross sections of K Q X-rays are one
or two orders of magnitude larger than those of K (3X-rays. Energies of K QI ,2 line in spectra of chemical compounds differ slightly, e.g. 0- 2 eV for third period elements, one from the other. It is expect ed thatchemical state analysis of the minor elements of 10- 110- 2% concentration is possible if the K Q line shift
can be measured with the precision of rvO .1 eV. We
examine here the ability of the in-air high-resolution
PIXE system for measurements of chemical shifts of
K Ql,2 lines, taking PIXE spectra of various samples
containing Si or P.
Details of the experimental setup are described in
the previous papers. 1-3) A target sample was placed in
air and bombarded with a 2.1 Me V proton beam of
1 mm x 1.5 mm rectangle. The emitted X-rays werediffracted by a flat analyzing crystal, detected by a
PSPC and recorded on a 512 multichannel analyzer.
Two laser pointers were set in front of the target forexact target positioning. The sample was set on an Al
target holder attached on an X-Y-Z stage. The stage
was adjusted so as to converge the two laser beams on
the surface of the target.
The chemical shifts of K Q1 ,2 lines were measured
with respect to the K QI ,2 line of a reference material. A silicon crystal (c-Si) was used as reference
for Si K Q and BP powder for P K Q. PIXE spectrafrom the sample and reference targets were recordedin succession in order to minimize experimental errors.
Measured samples were powders of chemicals of SiC,
Si3N 4, Ca3(P04h , CaHP0 4·2H 20 , Ca(H 2P0 4h·H 20,
plates of fused quartz (Si02), stainless steel N AS126(Si 3.5%), duralumin JIS2017 (Si 0.2- 0.8%) and GaP,P doped hydrogenated amorphous silicon deposited onquartz substrate (a-Si:H(P), P 0.7%) , a fragment of anearthenware of 2500 B. c. (P 0.8%) and a darkened partin the inner bottom of an Al pan.

Some of the measured Si K Ql ,2 and P K QI,2 spectra
are shown in Fig. 1. An InSb(111) crystal was used for
Si K Q as the analyzing crystal and a Ge( 111) crystal
for P K Q. One channel of the PSPC corresponds to0.106 eV in the region of Si KQ1 ,2 and 0.137 eV in theregion of P K Q1 ,2' As seen in the figure, energy shiftsof the K QI,2 peak position were clearly observed not
only for main components but also for minor components of the order of 10 - 1%.
The measured chemical shifts of Si K Q1,2 andP K QI,2 lines are listed in Table 1. The precision of
measurements (standard deviation) of less than 0.1 eV(a) P Ka 1,2,.....
"0
Q)

N

1.0

~

0.5

E
~

(b) Si Ka 1,2

0

0.0

'-"

1.0

1.0

.....>. 0.5

0.5

c

CI)

c

Q)

.....
c

0.0

0.0 ~1I!!8I!t~-~.31!ai1m1lilm¢

1.0:::~:~+..

>. 0.5

(OJ
~

I

><

0.0
160 180

200 220240

0.0 L.+-::-.-.:'----"-...:.....-.::........I
160 180 200 220 240

PSPC position (channel number)
Fig. 1. K Q1 ,2 spectra of P and Si.

Table 1. Chemical shift (.6E) of K 0.1,2 lines. n is thenumber of measurements and S. D. is the standard deviation. The reference material is c-Si for Si K Q and
BP for P Ka.
Element Sample
Si

P

n

I1E(eV)

5
Sial
5
Si3N4
SiC
5
duralumin (l1S2017) 2
steel (NAS 126)
2

0.68*
0.47*
0.21*
0.14, 0.16
0.20,0.26

+0.09
+0.05
:±0.05~(P04)Z4

CaHP°4e2HzO
Ca(Hl P04)ZeHz°
GaP
a-Si:H(P)Al panearthenware

4

0.85*
0.88
0.84*
- 0.06*- 0.030.81
0.82,0.83

±0.04
±0.07
±0.14
±0.06
±0.07
±0.06

4
8
4
4
2

S. D. (eV)*The shifts are similar to those obtained by X-ray fluorescence method. 3)

College of Engineering, Hosei University

175was obtained except for Ca(H 2 P0 4 h·H 2 0. This precision is enough for estimation of chemical bonding
states of the third period elements. This is, to ourknowledge, the first experiment in which the chemical
state analysis of minor elements (10-1 % order) contained in small amount of samples (10-1 mg order)
was directly performed in atmospheric air.

176

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., in press.

RIKEN Accel. Prog. Rep. 32 (1999)

Trace-Element Analysis of Feathers Using PIXE
H. Yoshiki, K. Maeda, A. Tonomura, T. Tsuruda, and H. Higuchi*
It is known that birds molt their feathers every year
and remove wastes such as heavy metals through thefeathers from the body.l ,2) Therefore, feathers may
have any information concerning annual emission of
toxic substances to air, water, and land. In this study,
we tried to analyze trace elements in feathers using
particle induced X-ray emission (PIXE).
Three individuals used in this study and their sampling locations are follows: adult jungle crow (Corvus
macrarhynchos) in Tokyo; adult bonin petrel (Pterodrama hypoleuca) on Haha Jima; adult white's thrush(Zoothera dauma) on Haha Jima. The biological dataof each species lists in Table 1. After being cleansedwith an ultrasonic cleaner in a commercial neutral detergent (Iuchi Seieido Co., Clean Ace S) for 1 h, thefeather was bombarded in air by 1.6 MeV proton beamof 3 mm diameter. A Si(Li) solid state detector with
8 J.lm thick Be window (EG & G Co.) and a graphite
sheet with 0.3 mm diameter pinhole (graphite pinhole
absorber) or 74 J.lm thick Al absorber was used to detect the X- rays emitted from the feathers.
Table 2 represents the concentrations of trace elements detected in the feathers. The concentration ofeach trace element was estimated from the sulfur concentration determined by an ion gas chromatograph,the peak area, and the ratio of X-ray yield. The feathers contained Ca on the order of 103 ppm dry weight,
Fe and Zn on the order of 10 2 ppm dry weight, Ti and
Sr on the order of 10 1 ppm dry weight, and Cu, Pb,
Se, Br on the order of 100 ppm dry weight except for

Table 1. Biological data of species used as samples.
Species

Distribution and habitat

Food

Total length(cm)

Body weight(g)Jungle crowSoutheastern Asia,
Forests and Cities
Ogasawara Islands,
Sea
Old World,
Forests

Animal carcasses,
Garbage, etc.
Fishes,Cuttle fishes, etc.
Earth-worms, Insects,
Fruits in forest, etc.

56.0

600 -750

30.0

150 - 200

29.5

130

Bonin petrel
White'S thrush

Table 2. Concentrations of trace elements in feathers.
Species

Ca

Ti

Mn

Fe

Jungle crow
Bonin petrel
White's thrush

4500
400
1200

45
15
<6

58
4
180

240
150
19

several data.
There existed significant differences in the concentrations of trace elements in the individual feathers.
The jungle crow's feather had higher concentrationsof Cu, Zn, and Pb than those in other feathers. In
particular, the concentration of Pb was much higher
in comparison with other feathers which contained Pb
less than minimum detectable concentration. A similar result has been obtained from the analysis of thefeathers of birds living in urban and rural areas using an atomic absorption spectrometry. 1) Taking consumption and disposal of many chemical substances
around Tokyo into account, these results indicate thatthe detected trace elements with high concentrations
result from man-made pollution.
On the other hand, the feather of the bonin petrel
had higher -concentrations of Se and Br. It is known
that marine products are rich in Se and Br. Since the

Ni
Cu
Zn
(ppm dry weight)
2
n.d.
n.d.

30
2

400
51
61

Se

Br

Sr

Pb

16

4
33
4

31
12

64
<4
<2

bonin petrel inhabits the sea and eats fishes and cuttle
fishes mainly, these differences seem to originate fromfood. The differences of concentrations of Ti, Mn, andFe between the bonin petrel and the white's thrush
seem to be related with the life environment such as
soil and water. However, since there is no reliable data
about the environment of Haha Jima, it is difficult to
discuss in detail.
In summary, the usefulness of PIXE was demonstrated for the multi-element analysis in the feathers
without any complex pre-treatment. In future, wewould like to apply the PIXE analysis of feathers to
the evaluation of environmental pollution.
References
1) L. L. Getz , L. B. Best, and M . Prather: Environ. Pollut.
12, 235 (1977).
2) K. Dmowski and M . A. Karolewski: Ekol. Pol. 27,333(1979).

School of Agriculture and Life Sciences, University of Tokyo

177

IV.

DEVELOPMENT OF ACCELERATOR FACILITIESRIKEN Accel. Prog. Rep. 32 (1999)

Improvement of Sextupole Magnet for RIKEN
lO-GHz ECRIS
M. Kidera, T. Kageyama, T. Nakagawa, J. Fujita, M. Kase, A. Goto, and Y. Yano
The 10-GHz Electron Cyclotron Resonance Ion
Source (ECRIS) at RIKEN is used as the injector of
AVF cyclotron accelerator. 1) Various heavy ions such
as C, N, 0, and Ar are produced by this ion source, andare supplied for various experiments. For a long-time
operation, a main problem of this source was a lackof stability in the beam intensity. Supply of a stablebeam is quite important for better experiments. 2 )In order to improve the performance of this ECRIS
we have designed a new sextupole magnet, and installed it in September '98. The maximum strengthof the new sextupole magnet is about 1.6 times that of
the old one. Cross-sectional view of the new sextupole
magnet is shown in Fig. 1. The specifications for the
new magnet are described in Ref. 2.
From September to October, the 11 B, 12, 13 C, 14N,
20Ne, 40 Ar, 56Fe, and 84Kr beams were stably supplied
from the mew ECRIS for users via AVF. The stabilityof the ECR plasma has clearly increased. Moreover,the stable beam eased the transportation of extracted
beam, because the beam tuning is usually done bymonitoring the change of the beam current received

permanent magnets

I,

o

"

I

50mm

Fig. 1. Cross-sectional view of the new sextupole magnet.

by the Faraday-cup in the beam-line. A comparison in
the beam intensity before and after the improvement
is shown in Table 1. Extracted beam intensity was
about 1.5 times greater than the old one for the low

Table 1. Intensity of ion beams from RIKEN 10-GHz ECRIS.

Old type

20

35

35

60

37

20

0.6

New type

36

74

75

135

68

35

3.0

charge state, and was about 5 times for the high charge
state(Kr 20 +). The ECR plasma was tuned to supply
a specified ion beam for the user for a limited beamtime only. Therefore, the beam intensities in Table 1
are not yet optimized for the each charge states of ions.

References
1) T. Nakagawaet al.: Jpn. J. Appl. Phys. 32,1335 (1993).
2) M. Kidera et al.: RIKEN Accel. Prog. Rep. 31, 182(1998).

179

RIKEN Accel. Prog. Rep. 32 (1999)

Off-Centered· Compact Duoplasmatron Negative Hydrogen Ion
Source with' Small Permanent Magnets
H. Tawara, K. Hosaka, and T. Tonuma
Experiments on the electron detachment from Hions under collisions with high-energy (MeV /amu)
highly-charged ions are under way,!) and we need areliable, compact H- ion source. Generally, negativeions can be obtained either through the double electron capture into positive ions, or by the direct ion
extraction from plasma sources. But the qualities of
directly extracted beam are known to be much better
than those formed by electron capture. The direct extraction of negative ions from electric-discharge plasma
sources is always accompanied with an intense electron
current which is usually more than three orders of magnitude larger than the extracted H- ion current (in hydrogen discharge plasmas), requiring a huge extraction
power supply for the ion source. Thus it is always a serious problem how to maximize the extracted negativeions and how to simultaneously minimize · the loading
electron beam current.
The most important processes in H- ion production in hydrogen plasma sources can be separated into
the following three steps:2) The first step' is the process of production of the vibrational excited hydrogenmolecules (H2 *), which requires relatively high energy
electrons:(1)
The second step is the process of slow electron attachment onto the vibrationaUy excited hydrogenmolecules H2 * (v). The cross sections for forming thetransient negative hydrogen molecular ions H2 - (forexample at v = 5~6) are known to become large resonantly more than six orders of magnitude than thosefor the vibrationally ground state molecules:

concentrate near the relatively cold, arc-edge region,and that at the arc-center region where the plasma~shot, the positive ions such as protons are dominant.
The present air-cooled, compact off-centered duoplasmatron ion source is shown in Fig. 1, where two
small ferrite permanent magnets (each 60 mm diameter and 5 mm thick) are used to focus the arc, flowing
out of the snout (intermediate electrode with a 2 mmdiameter hole), onto the anode aperture (0.3 mm' diameter) made of a 0.5 mm thick Ta plate which isinserted onto a soft iron plate. The maximum arc current which can run on this source is about 0.5 A.' Its
basic features of construction of the ion source are thesame as those describedbefore. 5 )A few parameters can be used to optimize the Hion output from the duoplasmatron ion source. One ofthem, which are most often used, is to change the relative position of the arc from snout against the ailOdeaperture. Most of the observations performed thus far'had confirmed that the ratios of the extracted negative ion current to the electron beam current can be
maximized: (1) by displacing the arc position relative to the anode aperture, (2) by changing the gaspressure in the ion source and (3) by changing the
distance between the snout and the anode aperture.
But the most important parameter is the displacement of the snout position relative to the anode aperture. It should be noted that even at the optimum
displacement, the ratio of H- ion current to electron current is a few % at best. It has also been
confirmed in the present ion source that the relative(2)
The third step is the process of dissociation of theseresonant state negative hydrogen molecular ions (H2 -)into the H- ion plus the ground state H(ls) atom:(3)
In the present collision experiments, small-scaled
negative ion sources with small arc power are more convenient. One of such negative hydrogen ion sources wasto use duoplasmatron ion source. It was noted sometime ago that proper displacement of the snout relative
to the anode (ion exit) aperture position in the duoplasmatron ion source had resulted in the productionof relatively intense H- ions, while significantly reducing the electron current. 3 ,4) Now this feature can beunderstood due to the fact that the H2 * (v) molecules
which are responsible to the production of H- ions180

Fig. 1. Schematic of the present off-centered duoplasmatron ion source for producing H- ions.

position ,o f the arc from snout against the anode aperture is quite sensitive to the H- ion production, as
observed previously. But the movement of the arc or
snout during the operation is quite cumbersome andsometimes not reproducible.
Moving the position of the snout is complicated, inparticular when the ion source is at a high voltage terminal. We have found that another procedure is moreconvenient and reproducible. It is to change the arc
current, which results in the change of the arc position
as well as the arc-column size. This is in principle

equivalent to moving the snout . Typical results areshown in Fig. 2, where the H - ion current is shown
as a function of the arc current and also as a function of the gas pressure in the ion source. As seenin Fig. 2(a), as the arc current increases, the drained
current increases steadily, meanwhile there is a sharp
optimum arc current which is equivalent to an optimum displacement of the snout and at the optimum
H- ion current is enhanced by a factor of roughly 10.
Also, some optimum gas pressure in producing H- ions
was found, as seen in Fig. 2(b).

(a)
0.70 . . . . - - - - , - - - . - - - - - , --1c:~--,r--- - , - ---,-

--,

0.60

:I

U

6

0.50

~

0.40

n•
:!
{!.

.

-g

0.30

C

..:.
c

0.20

~

:I

U

,g

0.10

____ H(·)1on- -8 - - Total ExIractIon Current (mA):i:

0.0 L-_--'-_ _L-..._--'-_
0.1

0.15

0.2

0.25

_

' - -_ - - . L_ - - - ' L - . _ - l

0.3

0.35

0.4

3

0.45

3.5

4

4 .5

Pressure (10'"3 Torr)

Arc Current (A)Fig. 2. (a) H- ion current as a function of the arc current. Also the total drained current (mostly due to the electron
current) is shown by dotted line. (b) H- ion current as a function of the gas pressure in the ion source at a constantarc current. Variation of the arc voltage as a function of pressure is also shown by open squares.

These observed features can be qualitatively understood through our present knowledge of H- ion production mechanisms described above. 2 ) Namely, because the electron attachment to the vibrationally excited hydrogen molecules, step (2) process, is strongly
enhanced at the low temperature plasma region, themaximum H- ions are naturally expected to be obtained at the plasma outer edges, instead of the plasma
center. Since the electron attachment to the vibrationally excited hydrogen molecules is expected to occur more abundantly near the circular, cold arc edge
region, we have also tried to extract H- ions frommulti-apertures (6 holes each 0.15 mm diameter) cocentered with the snout hole along 1 mm radius locatedon the anode. More ion beam has been extracted but
its quality was not always good.

By shifting the snout position toward the anodeaperture center, intense proton beam up to 10-50 /-LA
is easily obtainable from this compact duoplasmatron
ion source.
References
1) T. Tawara, T. Tonuma, H. Kumagai, T. W. Imai, D.
B. Uskov, and L. P. Presnyahkov: Phys. Scripta T, inpress.
2) J. M. Wadera and J. N. Bardsley: Phys. Rev. Lett. 4 1 ,1795 (1978).

3) G. P. Lawrence, R. K. Beauchamp, and J. L. McKibben:
Nucl. Instrum. Methods 32, 357 (1965).
4) L. E. Collins and R. H. Gobbett: Nucl. Instrum. Methods 35, 277 (1965).
5) H. Tawara, S. Suganomata, and S. Suematsu: Nucl.
Instrum. Methods 31, 353 (1964).

181

RIKEN Accel. Prog. Rep. 32 (1999)

Advanced Acceleration Concept Taking Place in ECRIS (I)
M. G. Niimura, A. Goto, and Y. Yano
For designing the next-step ECR ion sources(ECRIS) that can meet goals in upcoming projects,
a profound understanding of the physics taking place
inside the source is essential. The so-called third
generation ECRIS is required to deliver beams ofhighly-charged ions (HCI) at ever higher intensity, efficiency, and stability for the high-brightness hadroncollider, spallation and/or ECRIS-on-line radioisotope(RI) beam generation, and precision atomic physics
data acquisition, respectively.
Answer to the above requirements should be possible
if the electron temperatures and their spatial distributions are programmable based on the knowledge of theelectron acceleration mechanisms leading to the electron heating. As for this knowledge, however, we arestill on a half way at most, since the established theory
can not always predict what we observe: e.g., the radially hallow structure in the density as well as temperature distributions of electrons in ECRIS. Throughout
the history, the stochastic acceleration (STA) of gyrating electrons has been considered as the only mechanism leading to the electron heating. Naturally, thisprocess should not be all. Because, not all EM-waves
propagate in parallel to MMF particularly in a multimode cavity, not all wave elctric fields are of the EMwaves in a plasma medium, and not all electrons are
drifting along the magnetic field lines.
We have hence suggested another mechanism called
the cross-field acceleration (CFA) ,1,2) which we foundcomlementary to STA. For an example, the abovementioned hallow structure is impossible to explain
without a second harmonic (2we) heating for thecase of axisymmetric ECRIS. However, the 2we (orB EcR /2 resonance) heating should not become obsevable before raising the electron temperature (Tc)
above 200 ke V or unless kpL 2: 1.5, since the heating rates are proportional to the squared Bessel functions: J 12(kpL) and J 0 2(kpL) for the 2we and We

Ion Cyclotron

heatings, respectively. The aut hours anticipate that
STA alone would not achieve this T c within the timescale the hollow structure becomes observable.
The CFA can quickly raise T e of background electrons for STA. It is because CFA has two characteristicfeatures: one is the ability to accelerate cold electrons
even those at room temperature, and another is, unlike to the case of STA, the fast process that does notneed to wait the slow bouncing period before the next
heating takes place.
CFA is the result of an extraordinary (X) wave,
propagating perpendicular to the MMF, B zo . X-wave
can form regions of compression and rarefaction in electron density, thereby generating ES potentials along
the radial (r) direction of propagation. Oscillating ES
potential means oscillating longitudinal electric field,
E~s. This E~s and B zo are cross fields each other, basic configuration for CFA. Figure 1 shows schematic
views of the three acceleration mechanisms: Ion Cyclotron, STA, and CFA neglecting the scale of their orbitals. Only the STA and CFA are taking place insideof ECRIS, of course. Unlike the other two, the CFA isan advanced acceleration concept because the strengthof acceleration field does not directly depend on theimposing rf-power. It is internally generated together
with ES waves by a collective motion of charged particles. Internally generated E;s can grow significantly
larger than the externally applied rf wave electric field(ElM) by increasing the electron density (ne1)' [See,Eq. (15)]
For the ion cyclotrons, as is well known, the energy
gain per evolution is Ze E~Ml which is constant for agiven device. Here, 1 is the total length of acceleartion
gap. For the STA, on the other hand, the gain in thetransverse velocity (.6.v 1..) is constant per evolution.
From Fig. 1 we can express

Stochastic Acceleration (STA)(1)

Cross-Field Acceleration (CFA)

Fig. 1. Acceleration mechanisms taking place in ECRIS, to be compared with ion cyclotron accelerator.

182

Table 1. Difference and similarity of three acceleration
mechanisms.
lwhere Wpo ~ Jnco e2 /€om and W e ~ eBzo/mc ofplasma.
In order to investigate the relativistically accelerated
2D-motion of electrons under the cross-field condition,
we rewrite Eqs. (3) and (4) back to the original forms:
dVlr

-

e
I'mo

= - --[Elrdt+ V19 X Bzol

(10)e-dvtO = ---[-Vtr
X Bzol. /2I' == 1/y 1- (3; - (30'

acceleration

When an electron gyrates synchronously with E~M of
the right-hand polarized (RHP) wave [See, Table 1],
the effective interaction time (t e) is 27r / We per evolution. Then, Eq. (1) gives the velocity gain:
EEM

Bzo

-iwmVlr = -eElr - eVloBzo

(3)
(4)

-iwmVlz = 0(5)-iwnel = -ik· neovlr(ne = -ne V' v)(6)ik . EoEJr = -enel(V , D = p)

(7)Here, the suffixes zero (0) and one (1) indicate
the equilibrium and perturbed quantities, respectively. Perturbed electron density is thus in the form:
nel = nelei(kr-wt). Equations (6) and (7) tell that the
propagation direction of ES-waves is ID or ko = k z = 0
when El = Elrr is the only driving field considered.
Substitution of the V16 of Eq. (4) into Eq. (3) gives
VIr = (eElr/imw)(1 - w;/w 2 )-1, with which Eq. (6)yields:eEtr/ imw

(13)

V19

-iwmVIO = -evlrBzo

k

(12)

1/ Jl - ,B;h and ,Bph ~ V ph/C. Equation (11) gives
azimuthal electric field, along the wave front:(2)

Since E~M '" 30 kV /m and B zo '" 0.5 T typically,
Eq. (2) gives ~v 1- = 3.76 X 10 5 m/s per evolution.
However, notice that ~ v 1- = 0 if Bzo is uniform andif the parallel drift velocity (v / /) is much faster thanthe phase velocity of EM-wave, i.e., if v / / » W /k. Another difficulty for STA to explain 2we heating or hollow structure.
We have extended our previous works 2 ) treating the
problem of CFA by mathematically-rigorous and fullyrelativistic manners.
We have investigated the collective electron motion
when perturbed by the rf-field Elr(~ E~S) of X-wave(E lr ..1 Bzo). Such a system may be described bya set of the linearlized fluid equations in cylindricalcoordinates:= w-nco 1 -We21 W 2'

V19

Integration of Eq. (11) gives Vi6' in the moving frame:~V.L = 27r~ per evolution.

n el

Vtr

«(3r == - , (38 == -).
CcNow, we imagine a radially-moving frame moving at
the phase velocity V ph, where variables are expressedby the prime (') mark. Then, the particles are rest in
the r-direction or v~r = O. Since, r' = ,ph (r - V ph t) by
Lorentz transform, we have v~r = ,ph (VIr - V ph) = 0
and thus obtain VIr = V ph in Eq. (11). Here, ,ph ~during azimuthal
acceleration

(11)

I'mo

dt

(wlk = V ph)',pr)
= VphWe *,t , We* =_ W-:;'et, = I'ph (tV
- ~

(14)

However, VIe' = Vl8 because the frame is moving onlyin the r-direction, and t' ~ ,ph t if t » 0.3 ns, because
ric ::; 0.3 ns in our geometry and because V ph/C ::; 1
always.
Now that we know Wh/k = V ph, Eq. (8) can beused to obtain the amplitude of ES drive wave
E lr = Elrei(kr-wt+~):.~net mwpo Vph-IEtr = --.::..-~n eoeW2]-1/2[1 +--.£.
w~(15)

Here we used Eq. (9) for w, and nel/neo ~ 8 is thefraction of the electron density participating the longitudinal oscillation. Notice that the phase of E lr
is advanced by 7r /2 against the wave-potential, ¢ =- J eE1rdr = -(A/2)eE lr .
Since general operation condition of ECRIS is We ' "Wp '" Wrf, one can evaluate Eq. (15) in the form:
~

rv

Elr =

8 mwpo V ph c><
M- 2.26 8V ph ,
v2
e

(16)

if ne ~ 10 12 cm- 3 . The value of V ph can grow by the
background electron temperature according to the dispersion relation of Bn-waves. 3 ) For the Case 1 of Fig. 2
in Part II we have V ph = 6.47 X 10 7 mis, with which
Eq. (16) gives
Elr ~ 1.468 X 10 8 V 1m = 1468 MV 1m.

(17)

Therefore, the internally generated Elr is much bigger
than the externally imposed rf field (= 23 kV /m for
Minimafios) when 8 '" 0.01% or larger.

(8)

References

Substitution of Eq. (8) into Eq. (7) tells us that thesystem oscillates at the upper hybrid resonance (UHR)
frequency(9)1) K. S. Golovanivsky: Rev. Sci. lnstrum. 63, 2886 (1992).
2) M. Niimura: lnt. Workshop on ECRlS, INS-J-182, 141(1995); also, ECRIS-13th, Texas, p. 52 (1997).
3) 1. Bernstein: Phys. Rev. 109, 10 (1958).

183

RIKEN Accel. Prog. Rep. 32 (1999). Advanced Acceleration Concept Taking Place in ECRIS (II)M. G. Niimura, A. Goto, and Y. Yano
Mechanism of detrapping: Using the notationsof (I) , the radial force exerting on a trapped electron can be expressed by F~r = -e(Elr + Vle'Bzo),and Lorentz transform for the phase of E lr ==Elrcos(kr - wt + 11"/2) is given by kr - wt + 11" /2 =krf /,ph + (kV ph - w)t' + 11"/2 = krf /,ph + 11" /2. Then,
using the VIe' given by Eq. (14) in (I), we have
F 'r = - e[E, -krf + V ph B zowc* t 'J .
- A
Ir S1n(1),ph

The first term of Eq. (1) is the drive field, which canaccelerate the electrons trapped inside the space where
Elr s:: 0 or -sin krf /,p s:: 0 towards the positive rdirection. However, the second term is a deceleration
field: -Elr == VIe' xB zo . Therefore, as the time passes,
not only the I F~rl but also the radial size where Elr s:: 0
decreases [Fig. 1], thereby detrapping some of electrons
from the beginning (t :::: 0). Namely, all particles will
be detrapped if
Elr ::; 'ph V phBzow~t,(0.3 ns « t ::; to)(2)and the time of detrapping is given by
Elr- to= - __'ph V phBzoW~(3)

Since c :::: V ph and t :::: 1/We, if Elr is large enough tosatisfy(4)then once trapped particles will never be detrapped
before reaching the ECR-zone from inside.

\,+~'+T"'-t - 2~'­-It.*L~=I;'' ~phB.oW:

r(t) = Vpht + r' /,ph + rUHR

(5)

Os(t) = Vphw~t2 /2r + Os-I .

(6)

t'

i

Fig. 1. Detrapping dynamics of wave-trapped electrons.

184

r...J.

The figure plots the 2D-positions of a trapped-electronby the time-step of T e /l0 or of T == t/T e = 0.1 , 0.2 ,... ,till the detrapping time to. After each trip, the newvalues of Elf) to, and V ph were re-calculated with the
new Te resulted .
Forced detrapping on ECR-surfaces at We, 2w e ,21t~-+--~"""-t-~Figure 1 illustrates the dynamics of the particle detrapping, step by step: Oscillation in electron density
creates an ES potential (¢) wave, which can trap cold
electrons whose energy E: s:: ¢ = -(A/2)eE lr . Due tothe finite thermal energy of trapped electrons and dueto the focusing force of potential-well, only the domain [11"/2,11"] is considered as the useful phase. In theframe moving with V ph, trapped electrons feel a dc
azimuthal electric field Eo = (V ph X B~o)/( -e) which
accelerates them along the wave-front. However, a radially deceleration field, -Elr, is generated becauseof the V ph. Because this - E lr == Eir* in Fig. 1 andEir* = -VphBzow~t' from the second term of Eq. (1),the magnitude grows linearly with time (t = 0,1,2, ... ).
Consequently, as seen from Fig. 1, the radial domain
where E lr s:: 0 as well as the magnitude IF;rl decreases
gradually, thereby detrapping the trapped-electrons in
the layer marked by t = 0 rv 1 first , and t = 1 rv 2
next, followed by the layer t = 2
Skipping the mathematical details, here we will explain only what happens for trapped electrons during
the transient phase before the trapped particles canreach the ECR zone. Figure 2 displays total 9-trips ofthe longitudinal waves being launched from the UHRsurface. The very first trajectory had to = 0.123 ns.
The numbers indicate the V ph of the ES wave deduced
from dispersion relation of the electron Bernstein (Bn)wave. This is a single particle simulation, whererf (coordinates from the origin of moving frame) = O.
Trajectory of a trapped electron is governed by theset of equations:Fig. 2. Trajectories of trapped electrons for increasing
V ph.

... : Let us consider the case of strong- Eln so thatthe detrapping radius (ro) exceeds the ECR radius: i.e., ro == ~ro + r UHR ~ r ECR , since we define:~ro == ro - r UHR ' In this case, Elr is forced to decay
at r = rECR because there Bn-waves can satisfy theresonance (Vph = 0) condition: WBn = W~CR /q, whereq = 1,2, .. .. These particles have experienced the maximum acceleration time, until the forced detrap at
r = rECR, given byrECR - fUHR ~tmax =(Elr »"YphBzow~~fECR)(7)
Vph
Since VUJ = V phw~t from Eq. (14) in (I), we have at

1000

2000

3000

4000

5000

Mirror Magentlc Reid, B.. (Gauss)t = t max

vu;ax == VphW~tmax = W~~fECR'(8)

where ~rECR == r ECR - r UHR ' The kinetic energy atshell isw 8max = 21 m*(We*~ fECR )2 = IIlo
(9)2')' (~We
rECR )2 .
Thus, we obtain a formula for the shell energy calculation:o 1 _ WOax _ 1 (eBzo/mo)2 (~)2(10)')'8 moc2 - 2
')'c2
fECR
Here, the 'Y is given by Eq. (12) in (I), and obviouly'Y ~ 'Yo for the present case. Since f30 = viO ax / c ~ome9ae~rECR/'YO, we have 'Yo =+ (we~rECR)2 /c 2.
Therefore, Eq. (10) can be written as

VI')'0 - 1 = Woax = ~
moc2

This

gives

a

2c

(We~rEcR)2.

(11)

Vc2 + (We~fECR)2convenient

formulatocalculate

Woax (keV):_
W8max -

8.79 x 1O-5B;o(G)(~fECR)2(12)

VI + 3.43 x 1O-7Bio(G)(~rEcR)2

Here, we take Bzo(G) in Gauss unit and ~rECR in cm.
Equation (12) was evaluated for three different cases
listed in Table 1. These 3-cases are when the acceleration length (~r) is equal to ~rECR = 0.4 cm.
Figure 3 plots Eq. (12) for different ~rECR' It
is seen that W 0 increases quadratically with B zo inthe beginning, but increases linearly later for a large
Bzo. Wo = 1 MeV is found possible from Fig. 3 if
B zo = 3 kG and ~r ECR = 2.5 cm.
It is interesting to find that Eq. (9) is in the form:
Table 1. Hot electron energy W 8 at the shell for threecases.

.

Case 1
Bzo (kG) in the core:II) r{radls)m{cnr3)rII) / lo)!!

.v

vb

o

in the core:in the core:in tht: core:(em/sec) initial:~ 3.4110 :4. 14x10ll
6.9xlO'6.0xI0

0 .8&: 3.21: I.IxlO

3.50
10

Il

6.16xlO
4.Sx10

10

10

4.96

i 1.351 JO

I 2.1 Ox I 0

: 128

: 133

II:

I 1.31 x I 0

Wp{keV)at Ar-o.4 em: : 68

Case 3: Case 2

2.35

9

9

Fig. 3. Hot electron energy on the ECR-surface as afunction of the MMF, Bzo.
W max
8

1 (B

~

= 2m* e zo fECR

)2 _

p2

= 2m*

(13)

and p == eBzo~r ECR'
Since the magnetic rigidity is equal to a relativistic momentum, i.e.,eBZO~rECR = 'Ymv, Eq. (13) is a relativistically valid
formula.
CFA has the same formula as the ion
cyclotron to determine energy provided that ~r ECR== rECR - r UHR is used rather than the radius (r) itself
for the magnetic rigidity.
CFA mechanism can explain the formation of aclosed-shell (ring) and discrete spots of hot electrons
for the axisymmetric (or radially max-Bzo) ECRIS andnon-axisymmetric (min-B) ECRIS, respectively. In theaxisymmetric case, only the 2we surface is resonant forradially expanding cyclindrical waves, thereby creating a single hot-electron ring on the midplane (where
B zo ..L VB zo ) eventually due to a restoring force of theinflated line of force of MMF there. In the min-B case,the We surface is not always a circle but often follows
the multi-cusp geometry, to which cylindrical waves
are expanding. Then, the contact points of the wavefront and We surface are discrete spots, not a ting, as
observed'!)Cnclusions are: (1) Expression of the longitudinal
wave electric field valid under B zo was derived, (2) Detrapping dynamics was clarified, (3) The resonantly
detrapped electron energy was formulated relativistically for the first time; (4) Most significantly, strong
B zo was found to heat up the hot electrons effectively.
If hot electrons form a ring and if its current is large,
the diamagnetism depletes the Bzo field inside of it:then cooling of hot electron ring starts and all other parameters start oscillating. 2) Presence of a hot electron
ring surrounding ECR-zone in the mid-plane means an
extra space charge, creating a deeper and wider potential well. Axial e-beam injection seems to enhance thiseffect. 3 )References
1) J. Vamosi et al.: ECRIS-13th, Texas, p. 206 (1997).
2) M. Lamoureux et al.: ECRIS-13th, Texas, p. 67 (1997).
3) T. Nakagawa: private communication.

185

RIKEN Accel. Prog. Rep. 32 (1999)

Model Study of a Resonator for Flat-Top Acceleration Systemin the RIKEN AVF Cyclotron
S. Kohara, O. Kamigaito, M. Kase, E. Ikezawa, Y. Miyazawa, T. Chiba, and A. Goto
A full-scale model of the flat-top resonator to be used
for a flat-top acceleration system in the RIKEN AVF
Cyclotron was fabricated, and was coupled to the existing main resonator in order to verify the design. 1 ,2)The flat-top accelerating voltage is generated by a superimposition of the fundamental-frequency and 5thharmonic-frequency voltages. The flat-top resonatoris used to generate the 5th-harmonie-frequency voltage. The fundamental-frequency voltage is generated
by the main resonator. The fundamental-frequency
range is from 12 to 23 MHz. Due to the 5th-harmonicfrequency the frequency range is required to be from 60
to 115 MHz. Result of the cold model test performed
with the flat-top acceleration system is described inthis report. 3 )The cross-sectional views of the main resonator andflat-top resonator are shown in Fig. 1. The flat-top
resonator shown inside the square of dashed line isdesigned to be a coaxial resonator with a movable
shorting plate, and is coupled with the main resonator
shown in the left hand side of Fig. 1 via the coupling
capacitor (Cc). A photograph of the flat-top resonator
prototype installed on the existing main resonator isshown in Fig. 2.
In the cold model test, the resonant frequency of 5thharmonic voltage was measured to see if the required
frequency range can be achieved. In the measurement,

Fig. 2. Photograph of the model flat-top resonator installed on the existing main resonator.
both the coupling capacitor (Cc) and the movable
shorting plate of flat-top resonator (L5) were adjusted
after the movable shorting plate of main resonator(Lavf) was set for the fundamental frequency. In thiscase, the 5th-harmonie-frequency signal was fed into
the flat-top resonator through the voltage pick-up of
5th-harmonic frequency and was monitored by the dee-

Movable shorting plate~

Flat-top resonator

70

()

~
0

60
c

0

Main resonator

150

~

~

50

~

.5
0

-5
o

40

c..
co

e

:g

I
4CW50,OOOE A -------------~

Vacuum capacitor

=:

IOU

~

30

0

~

Capacitive tuner

L:::,.
20

0

c

0

0

10 ~

6.

0

.

~

C.",dtivef<ede<~\---r='--<IC'\ 4JJ1-----rr--

50

6.

.s
~

0

~

~

50

60

70

80

90

100

110

~

o
c
o

~

120

Stb-hannonic-resoo.nl frequency (MHl>Dee-voltage pickup

o

50

lOOcm

Fig. 1. Cross-sectional view of the resonators of flat-top
acceleration system for the RIKEN AVF Cyclotron.
186

Fig. 3. Positions of the movable shorting plates ofthe flat-top and main resonators as a function of the
5th-harmonic resonant frequency. The capacitance ofthe coupling capacitor (Cc) was 16 pF. Circles represent the position of the shorting plate of the flat-top
resonator. Triangles represent the position of the shorting plate of the main resonator.

voltage pickup. It was found that the 5th-harmonicresonant frequency was successfully generated on thedee in the whole required frequency-range along withthe fundamental-resonant frequency. The measured
positions of the movable shorting plates of the flat-top
and main resonators are shown in Fig. 3 as a functio of the 5th-harmonie-resonant frequency. This result gives the specifications of flat-top resonator, which
proves achievement of the required frequency range.
The moving distance of shorting plate and the lengthof resonator should be at least 57 and 66 em, respectively, when the coupling capacitance (Cc) is set to be
16 pF. The measured 5th-harmonie-resonant frequency
was found to be very close to the frequency 5 times
2500

0

. .
0

2000

0

0

0

1500

Oc

1000

as large as the fundamental frequency. The measured
Q-values of the fundamental and 5th-harmonic modes
as a function of the resonant frequency are shown in
Fig. 4 (a) and (b) , respectively. The measured Q-value( Q 1) of the fundamental mode was found to vary from1500 to 2400 , while the measured Q-value (Q5) of the
5th-harmonic mode was from 300 to 740.
In the cold model test, the flat-top accelerating voltage was generated by feeding low-level signals of thefundamental and 5th-harmonic frequencies at the sametime. In this case, the fundamental-frequency signal
was fed into the resonator through the vacuum capacitor, while the 5th-harmonie-frequency signal was fed
into the resonator through the capacitive feeder of theflat-top resonator. The flat-top accelerating voltage
generated on the dee was measured by the dee-voltage
pickup. The amplitude and phase of the 5th-harmoniefrequency signal were adjusted to obtain the flat-top
voltage on the dee after those of the fundamentalfrequency signal were fixed. It was found that the flattop voltage can be generated in the whole frequency
range. The typical wave form of the flat-top voltage isshown in Fig. 5. Design of the real resonator is underprogress.

500

(a)
IO

12

14

16

18

20

22

24

Resonant frequency (MHz)

800

•

o
700

•

0

600

500

g

6"

o

o

400

o
o

300

.

200

100

Fig. 5. Typical wave form of the flat-top voltage measured
by the dee-voltage pickup. The fundamental frequency
was 23.55 MHz and the 5th-harmonic frequency was
117.75 MHz. Horizontal time scale: 5 ns/div., Verticalvoltage scale: 5 mV/ div .

(b)
50

60

70

80

90

100

110

120

Resonant frequency (MHz)Fig. 4. (a) Q-value of the fundamental mode as a function of the resonant frequency. (b) Q-value of the
5th-harmonic mode as a function of the resonant frequency.

References
1) S. Kohara et al. : Proc. 11th Symp. on Accelerator Science and Technology, Harima, p. 194 (1997).
2) S. Kohara et al.: RIKEN Accel. Prog. Rep. 31, 198(1998) .
3) S. Kohara et al. : Proc. 15th Int. Conf. on Cyclotrons
and Their Applications, to be published.

187

RIKEN Aeeei. Prog. Rep. 32 (1999)

Measurement of the Pumping Speed and Pumping Capacity for
Photon Detection System
K. Ikegami, D. Wu, and M. Wakasugi
The pumping speed and pumping capacities of aphoton detector l ) were measured. The photon detector (PD) in question is the one developed to measure the atomic transition energy precisely in the highenergy and highly-charged ion beams. Technology ofa cryopump was applied for this detector to reducethe background produced by collisions between the ion
beam and residual gas. This detector has two cylinders
inside the vacuum chamber as shown in Fig. 1. The
inner cylinder was made of copper and painted black,and charcoal chips were pasted at its central region.
The inner cylinder was connected to the second stageof refrigerator of the cryopump and was cooled down

300 - - - - . ; . - 300~

to 18 K. The size of the inner cylinder was 112 mm
in inner diameter and 960 mm in length. The outercylinder is a heat shield to protect the inner cylinderfrom any thermal radiation. Diameter of the outercylinder was 150 mm. This was also painted black andcooled down to 80 K by connecting it to the first stageof refrigerator. These cylinders have 22 holes at thedetection region in order to mount ten photon-counting
units (two holes for each unit) and two vacuum gauges.
The total radiation power on the surface of the innercylinder was estimated to be 9.5 W. The refrigerator
has a cooling capacity of 10.5 W for the second stage
at 18 K and of 68 W for the first stage at 80 K.

3001
Photomultipliers
I

Dichroic FiltersIuv Quartz Lenses

Charcoal Pannel
2nd. Stage Cooler (15 K)
1st. Stage Cooler (80 K)

Fig. 1. The photon detector.

One side port of the PD was connected to a calibrated gas flow controller and another side port was
to a turbo-molecular pump through a valve. To measure the characteristics of performance of the PD wefirst evacuated the detector with the turbo-molecularpump and then started a cryopump.
The cool down time of the second stage to 17K was
7 hours as shown in Fig. 2, while the pressure was below 1.8 x 10 - 6 Pa. After closing the valve the pumping
speed of cryopump was determined from the pressureand gas flow rate. The measured pumping speeds for

188

nitrogen and hydrogen were 7 x 10 5 Zisec and 80 Ilsec,
respectively.
We have also measured the pumping capacities fornitrogen and hydrogen keeping the flow rate of gases
constant. In the case of nitrogen, after keeping a
constant flow rate of 9.52 x 10- 6 m 3 Pa/sec for 195
hours, pressure and temperature rose slowly at firstand rapidly later. Figures 3 and 4 show the changes oftemperature and pressure with time when nitrogen gas
was admitted at a constant flow rate. Pumping capacity for nitrogen was estimated to be 6.7 m 3 Pa. In the

300

'~

250

g
e
~

200

~

150

,

~

50

. J
Temp. _

g

L,

100

I
~

Temp.

j

~

~

Q.)

Eo<

100

I

~

)....

............ '" ....,............

.-.,I...., ....,,...., --.

o

50

100

~

~

~

~

-

"

'1(~
I~~

o
o

100

200

300

500

400

lO

150

200

Cooled down time (min)Evacuation time (hours)

Fig. 2. The cool down time of the second stage for thephoton detector.

Fig. 4. Temperature rise with time when nitrogen was
admitted at a constant flow rate.

----.- Pressure
lO·2
';'

E::!~

51
~

t:l..

lO-3

.......-... ____ If'--.........

~

50

100
Evacuation time (hours)

150

~

200

case of hydrogen, after keeping a constant flow rate of
3.33 x 10- 8 m 3 Pa/sec for 240 minutes, the pumping
capacity was estimated to be 2.6 x 10- 4 m 3 Pa.
The pumping speed and pumping capacity of thehydrogen were much smaller than those of the nitrogengas due to a small amount of activated charcoal chips
pasted. Nevertheless, it was found sufficient to keep
the operating pressure of order of 10- 6 Pa for 2 or 3
weeks (in the case of long machine time). Because, in
general, the main component of residual gases in theunbaked chamber is the water vapor.
If hydrogen is assumed to be the main component ofresidual gases at the pressure of 5 x 10- 6 Pa, we can
expect that the pressure can be kept constant for morethan 3000 hours.
References

Fig. 3. Pressure rise with time when nitrogen was admitted at a constant flow rate.

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

189

RIKEN Accel. Prog. Rep. 32 (1999)

Present Status of RIKEN Microbeam ProjectN. Fukunishi, M. Kobayashi, A. Yoneda, M. Kase, and Y. Yano
We have made several researches to realize a heavyion microbeam which is a new powerful tool in biophysics. To start with the project, we chose a beamcollimation method for the purpose to produce aheavy-ion microbeam. In this method, we inserted avery fine collimator just before a target and ideally
speaking, a very small part of the beam should havepassed through the collimator before hitting the target. We tried this method, but failed to obtain a finebeam. The heavy ions scattered from the collimator
might have worsen the beam quality. Thus, we have
tried an alternative method as follows.
We employed an energy degrader with a very small
hole instead of a collimator. Some heavy ions will lose
their energies here, but a few ions may pass throughthe hole without losing energies. We separate theenergy-lowered ions by using the slits inserted on thedispersive focal point of the beam course. The ionswhich passed through the hole are collected on thetarget. The energy degrader and the slits are inserted
in the upper stream of the beam course (Fig. 1), andtherefore the scattered ions will give little effect on thetarget. The size of the beam is determined by the sizeof the hole times the magnification factor of the beamtransport system.
We made an experiment to testify the effectiveness of the method. We chose a 80 J.Lm-thick eu foil
as the energy degrader, which had many holes (seeFig. 2). The diameter of the hole was 100 J.Lm. The
135 MeV/nucleon 2oNe 10+ ion will lose 1% of its energy when passing through the energy degrader. On
the dispersive focal point, the separation of the beam isFig. 1. Setup of the test experiment.

190

(mm)

0
-0.25
-0.5
-0.75

beam (object)beam(ima e)• •• • ••O.1mm<l>•

••
••••
••

-1

-1.25
-1.5
-1.75
-2

-1

-0.5

0

0.5

1
(mm)

Fig.
2. Result of the experiment of beam size inx(mm)-y(mm) coordinates. The energy degrader isplaced at the object point of the ion optical system.
The energy degrader has many holes as shown in the
figure(object). The ideal image of the beam at the PSD
position(image) is also shown.

26 mm, much larger than the beam extent. The magnification of the beam was 0.63 for the horizontal direction and 1.26 for the vertical direction in present case.
Position-sensitive Si detector (PSD, S2044 HAMAMATSU) was set at the end of the E3A beam course tomeasure the size of the beam. The position of the ion
was determined based on the charge division method.
The sensitive area of the PSD is 4.7 mm x 4.7 mm.
The experimental setup is summarized schematicallyin Fig. 1.
The performance of the PSD was examined by using
241 Am-a source. The result showed a good positionlinearity even if an ion hit the edge of the detector. We
also found that the PSD had a sufficient position resolution at least for the a-particle emitted from 241 Am.
We obtained very sharp peaks as shown in
Fig. 2.
Each peak corresponds to a hole of theenergy degrader. The size of the peak is roughly
70 J.Lm(horizontal) x 300 J.Lm(vertical). The resultshows that the new method works well, basically. On
the other hand, the beam size in the vertical direction
is much larger than the ideal value (126 J.Lm). We also
found by moving the slits that image of the holes is rotated by nearly 45 degrees. It means that the opticalsystem for ions and/or its tuning is poor. We are now
investigating these points.

RIKEN Accel. Prog. Rep. 32 (1999)

Design of a Charge-State Multiplier System for the RIKEN
RI-Beam Factory Project
O. Kamigaito, M. Kase, Y. Miyazawa, T. Chiba, M. Hemmi,
S. Kohara, E. Ikezawa, A. Goto, and Y. Yano

In the RIKEN RI-Beam Factory project, a ChargeState Multiplier (CSM) system is planned to be placed
between the existing heavy-ion linac (RILAC) and ring
cyclotron (RRC) in order to increase the charge-tomass ratio (q/m) of the heavy-ion beams. It consists ofan accelerator, a charge stripper, and a decelerator. 1 )The accelerator section increases the stripping energy
further and the decelerator section brings the beamenergy down to the initial value. For the accelerator
and decelerator sections, drift tube linacs of variablefrequency type will be used. The total voltage-gain
required for the accelerator and decelerator sectionsare 25.6 and 12.5 MV, respectively.
In the initial design,2) four accelerator tanks and two
decelerator tanks were proposed, where 16 or 18 rf-gaps
were included in each tank. The resonator is based on
the Interdigital H-mode (IH) structure with a movable
shorting plate. The maximum gap voltage was chosen
430 kV in order to put the whole CSM system within
the present RILAC building. However, the estimatedpower consumption per tank becomes too high to beprovided with a conventional rf-amplifier. Moreover,the calculated current density reaches 90 A/em, whichis quite high, on the sliding contact around the cornerof ridge of the IH-structure.
Therefore, we have changed the configuration of the
CSM as shown in Fig. 1. Now the accelerator and decelerator sections are divided into eight and four tanks,
respectively. Each tank has now only eight rf-gaps
in it. The tanks are independently operated at the:-Ch~g-e-St~;e-M~itipli;r-(CSM) ,3.8 MeV/usecond harmonic frequency of the fundamental, whichmeans that the frequency of the CSM ranges from 36
to 76 MHz. The last single tank of the decelerator
covers the same energy-range as the first two tanks of
the accelerator. In the same way, there are a pair ofaccelerator tanks and a decelerator tank which work inthe same energy region. A quadrupole triplet is placed
between every two tanks.
The synchronous phase of the accelerator tanks is
chosen to be -25° , while that of the decelerator tanks
is 25°. The total length of the accelerator and that ofthe decelerator will be about 16 meters and 8 meters,
respectively. The drift-tube parameters have been optimized by using a beam simulation program which was
newly developed based on a first-order calculation procedure. According to the simulation, the beam transmission through the CSM is fairy good for the assumed
transverse emittance of En = 1.8 7r mm·mrad and longitudinal one of EL = 500 7r keY /u·deg at 54.4 MHz.
Construction of the low energy part of the CSM,
indicated by the three hatched circles in Fig. 1, hasstarted, and the mechanical design of the resonators
has been almost finished. The main parameters of thelow energy part are listed in Table 1. _The resonatoris based on a quarter-wavelength resonator of circularcylinder, as shown in Fig. 2. The resonant frequency
Table 1. Main parameters of the low energy part of the
CSM tanks. Acel and Acc2 are the accelerator tanks,and Dec is the decelerator tank. cPs denotes the synchronous phase. The input (Ein) and output (Eout )energies correspond to the acceleration condition at
54.4 MHz. The effective shunt impedance (Zeff ) is estimated at this frequency. The maximum current density
on the sliding contacts (J) and the power loss (P) are
estimated at the highest frequency of 76 MHz.
Tank

Accl

Acc2

Dec

Frequency (MHz)

36-76

36-76

36-76

Mass to charge (m/q)

26-6

26-6

12-2.7

Input energy* (MeV/u)

1.48
1.74

1.74

2.01

2.01

1.48
1.3

Output energy* (MeV/u)
Inner length (m)

1.3

1.3

Number of gaps

8

8

8

Bore radius (cm)

1.75

1.75

1.75

Synchronous phase (<1>.)

-25 0

-25 0

+25 0

Max. gap voltage (kV)

450

450

450

Max. power loss (P: kW)**

50

52

50

Zefr (Mn/m)*

171

178

169

Max. current (J: Alcm)**

58

61

58

* : At 54.4 MHz

Fig. 1. Schematic layout of the CSM. The beam energies
shown are those at the frequency of 54.4 MHz.

** : At 76 MHz (the highest frequency)

191

2.4

Dec ____

a 2.3

,,~

~

6
Q)
(,)

22

§

1
.§ 2.l$1300••.......•.
...•...

i:::;:s

..c

$500

2.0

U)

.....•.....

1.9
30

Shorting
Plate

'

40

70
50
60
Resonant Frequency (MHz)80

Fig. 3. Calculated shunt impedances of the resonatorsof the low energy part. The solid, dotted, and dashedcurves represent the impedance of the accelerator1, accelerator2, and the decelerator tank of the CSM, respectively.
Side View

Fig. 2. Schematic drawing of a tank of the low energy
part.
can be changed by a movable shorting plate. The rfpower is fed through a capacitive feeder. A capacitive
tuner is used for the fine tuning of the resonant frequency. The rf-characteristics of the resonators havebeen studied with the MAFIA code. All the three resonators have the same dimensions except for the drift
tubes and their stems. The size of the coaxial part aswell as the shape of the stems for the first and final
drift tubes were optimized so that the current density
on the sliding contact becomes minimal. The calculation predicts that a stroke of 1300 mm of the movable
shorting plate can cover the required frequency-range
from 36 to 76 MHz. The current density on the sliding
contacts is estimated to be 60 AI cm at the maximum
gap voltage of 450 kV.
Figure 3 shows the calculated shunt impedances.
The shunt impedance Rs is defined in present paper
by V 2 /(2P), where P is the rf-power consumption and
V is the peak value of the gap voltage. From this result, the maximum power loss is calculated to be about
50 kW per tank. The actual shunt impedances of theresonators will be, however, less than the calculatedones, mainly due to the sliding contacts around theinner conductor of the coaxial part. Therefore, we areplanning to construct the amplifiers whose maximum
power is 100 kW in the required frequency-range. The
calculated Q-values are about 30000, and they are almost constant over the frequency range of our interest.
The gap voltage distribution is not flat along thebeam direction in these resonators, particularly not at
the high frequency. As shown in Fig. 4, the gap voltage

192

~
~

I v--:,"" "" "O';'::;"""••• •• /r _~0.9.... /

o:s

~

/

/

.........

'.:::~.:.=.~~:: 34MHz'. 57MHz~\,>-§- 0.8 J/ t - - - - - - - - - - - - - - - - j 78MHzo
0.7 L-_~_.l....__.l....__....I...__....I...__...L_------'
2
4
6
1
Gap Number

Fig. 4. Calculated gap voltage in the second accelerator
tank. The resonant frequencies are indicated ouside of
the frame of graph.
in the end cells is only about 80% of that in the inner
cells at the highest frequency (78 MHz). The effect of
this voltage distribution on the beam transmission has
been estimated with the beam simulation. According
to the simulation, the transmission will become goodenough if the average gap voltage is made larger thanthe designed value.
Construction of the low energy part will be completed in 1999. The three tanks will be installed andtested in the beam line between the RILAC and the
RRC within the same year. The rest of the CSM tanks
will be designed based on the test results of the low energy part.
References
1) Y. Yano et al.: Proc. PAC97, TRIUMF, May 12- 16,
1997, in press.
2) A. Bandyopadhyay et al. : RIKEN Accel . Prog. Rep. 31,
203 (1998).

RIKEN Accel. Prog. Rep. 32 (1999)

Status of the Two Booster Ring Cyclotrons
for RIKEN RI Beam Factory
A. Goto, H. Okuno, T. Kawaguchi, J. Ohnishi, T. Mitsumoto, T. Tominaka, S. Fujishima,
J.-W. Kim, K. Ikegami, N. Sakamoto, K. Sugii, T. Wada, T. Morikawa,Y. Miyazawa, O. Kamigaito, M. Kase, and Y. Yano
Construction of both of IRC (Intermediate Ring Cyclotron) and SRC (Superconducting Ring Cyclotron)has been approved to start from the fiscal year of 1998.
Fabrication of the sector magnets of IRC has alreadystarted. Each of the upper and lower poles of IRC isdesigned to be divided into two slices for the simplification of assembly of the sector magnet in the cyclotron vault: i.e. the two slices faced to each otherwith respect to the median plane are assembled together with a vacuum chamber at the factory, and thewhole assembled components are to be delivered to thecyclotron vault (see Fig. 1). A Purcell gap of 1 mm is
designed between the pole and the yoke. Fabricationof the materials of the poles and yokes has been almost
completed.
SRC has been redesigned to have four main rf resonators from three in previous design (see Fig. 2). Thisdecision was made to obtain a better beam extraction
efficiency by enlarging the turn separation, despite that

Yoke

Fig. 1. Cross section of the pole part of IRC along thesector center line.

design of the components such as injection and extraction elements, a flattop resonator, and beam diagnostic
devices becomes tight due to the lack of available space.
These components have been redesigned accordingly.

~sooo~
Fig. 2. Plan view of the redesigned SRC with four main rf resonators.

193

Fabrication of the prototype sector magnet of SRC
is still being continued. In spring 1998, two sets of themodels of main coil assembly in the straight section,
which have a real-size cross section and are 60 cm inlength, were made to study the assembling and mechanical stiffness in the two adopted schemes (screwtype and hook-type) .1) A photograph of the model ofthe screw-type is shown in Fig. 3. The main coil winding of the prototype sector magnet started in August
1998. As of December 1998, the winding has been
completed and the final assembling of the remaining
coil vessel plates is being made. Figure 4 shows a photograph of the main coil vessel where several turns ofmain coils are being wound. Three sets of 1/6-scaled
sector magnets with normal conducting coils, which
are to be operated in a pulse mode, are being con-Fig. 4. Photograph of the main coil vessel where several
turns of main coils are to be wound (hook-type).

structed to measure the unbalanced magnetic forces in
x, y, and z directions. Its testing will be completed
around the end of December 1998. The results will beutilized for the design of thermal-insulation supportsof the cold mass. Fabrication schedule for the wholesystem of the prototype is delayed: cool down test of
the whole system and measurement of magnetic fields
have been rescheduled to b~ made in the summer of
1999.
An international technical advisory committee(TAC) was held in May 1998 for the review of designof the superconducting sector magnet of SRC. Detailsof each component are given elsewhere in this progress
report.
References
Fig. 3. Photograph of a model of main coil assembly inthe straight section (screw-type).

1941) T. Kubo et al.:(1998).

RIKEN Accel. Prog. Rep. 31, 210

RIKEN Accel. Prog. Rep. 32 (1999)

Design Study of the IRe for RIKEN RI-Beam Factory
T. Mitsumoto, A. Goto, M. Kase, H. Okuno, J. Ohnishi, O. Kamigaito,
N. Sakamoto, Y. Miyazawa, and Y. Yano
The RIKEN Intermediate Ring Cyclotron (IRC)
is a booster ring cyclotron for the RIKEN RI-Beam
Factory,l) which accelerates the extracted beam fromthe existing RIKEN Ring Cyclotron (RRC). Required
performance for the IRC is shown in Fig. 1 by lightgray area. The maximum energy and the maximum
magnetic rigidity is 126.7 MeV/nucleon and 4.57 Tm,
respectively.
Figure 2 shows a plan view of the IRC. Four sector magnets , two main RF resonators, one flat-top resonator, and injection and extraction devices are shown.

Diameter of the cyclotron is 14 meters. Main parameters of the IRC are listed in Table 1.
Table 1. Main parameters of the IRe.
Number of sectors
Harmonics
Average radius:
Velocity gain factor
Number of cavities

4

Injection

7
2.77 mExtraction

5.36m
1.5
2

Main
Flat-lop

Gyration frequency

2.57-5.45 MHz

140
120

C

g

100

'0

::I

c:

:>

80

Q)

~
>-

60

!:!'
Q)
c:

UJ

40

IRe
24.4

20
0
0

0.1

0.3

0 .2

0.4

0.5

q/A

Fig. 1. Required performance for the IRe is shown by
light-gray area. The performance of the RRC is shownby dark-gray areas.

14000_.+ ._-- -The fundamental structure of the sector magnetsof the IRC is quite similar to that of the RRC. Parameters of the sector magnets are listed in Table 2.
Cross-sectional size of the main coil is 160 mm (width)by 390 mm (height). Overall current density of themain coil becomes less than 1.5 A/mm 2 • This realizes
low power consumption of main coils. The magnet is
equipped with 20 sets of trimcoils. The trimcoils areattached on the pole pieces, where the vacuum is separated from that for the beam by stainless steel membrane. The trimcoils are carefully designed to be of low
power consumption. A so-called Purcell gap of 1 mm

Table 2. Main parameters of the sector magnets.

Pole gap

8cm

Sector angle

53 degree

Total hight

5.2m

WeightMaximum magnetic field

640 X 4 ton
1.9 T

Main coil
Maximum current
Maximum excitation current
Current stability
Power consumption of main coils

450 A
5

1.78 X 10 At

2 X 10 -5
82 X4kW

TrimcoilNumber of trimcoils
I
I
I
I.. ----1.-.-.-- 1

20

Maximum current

500 A

Current stability

5 X 10.4

Power consumption of trimcoils

45 X4kW

Fig. 2. Plan view of the IRe.
195

is designed to ~e set between the pole and the yoke.
The pole gap of 80 mm is estimated to decrease by
0.4 mm at maximum due to a bend of the pole , whichis caused by the magnetic and vacuum forces.
Magnetic field of the IRC was calculated by using
TOSCA-3D magnetic field calculation program. 2 )Equilibrium orbits and isochonous conditions werethen calculated by using the result of magnetic fieldcalculation. The main coil and trimcoil currents are
optimized by several iterations of the field calculations. Figure 3 shows the tune diagram of the IRe.
By optimizing 20 sets of trimcoil currents, errors toisochronous condition can be less that ±0.05 % for all
acceleration regions.

qli\=IU~8

X200.0/)J

Fig. 4. Geometrical sizes of the sector magnet of the IRefor calculation.

24.4M~V/1iN>

0.5~---:-'-:------:"':---~~--:-I-:-_ _~

1.0

1.3

1.4

Radial betatron frequency v r

Fig. 3. Tune diagram of the IRe.

onator was adopted. Frequency is adjusted by the flapof two panels in the cavity. This type of resonator hasa large advantage in that the area of sliding RF contact
can be minimized. The maximum voltage is supposed
to be 600 kV for one resonator.
For the flat-top cavity, however, a single gap typewith conventional short plates was adopted because oflimited space. Required voltage is about 1/9 of thevoltage needed originally by two main resonators.
Construction of the sector magnets has been started.
The whole components of the IRC will be completed
at the end of the fiscal year 2000.
References

Figure 4 shows the model for calculation of the sector
magnet with TOSCA.
For the main RF resonators, a single gap type res-

196

1) A. Goto et al.: RIKEN Accel. Prog. Rep. 31, 205(1998).
2) Vector Fields Limited, Oxford, England.

RIKEN Accel. Prog. Rep. 32 (1999)

Orbit Analysis of RIKEN Superconducting Ring Cyclotron
T. Mitsumoto, A. Goto, J. W. Kim, T. Kawaguchi, H. Okuno, J. Ohnishi, S. Fujishima,
T. Tominaka, N. Sakamoto, Y. Miyazawa, and Y. Yano
The RIKEN Superconducting Ring Cyclotron(SRC) utilizes the leakage magnetic field in its valleys
in order to increase the vertical focusing force. The
leakage field is still large outside of the cyclotron vault.
At the points 50 m away from the SRC center, it is estimated that more than 1 Gauss will be observed. 1) In
order to cancel the field outside the cyclotron vault,
two methods are considered. One method is to use aniron plate surrounding the vault. Thickness of the ironplate is required to be 16 cm. Total weight of the ironplate is approximately 2600 tons. The other method is
to use shielding coils. The shielding coils will be put on
the wall of the vault. Radius of the coil is 12 meters.
Required current is 360 kA.2)
From the orbit analysis point of view, both methods
affect on the field distributions and beam dynamics .
Figure 1 shows the influence of two shielding methods
on the betatron frequencies. In the case of the ironplate method, vertical betatron frequency decrease by
0.01 because the plates work as a return yoke. The
shield coil method does not change the betatron frequency much.
We plan to adopt the shield coil method from theview point of copstruction cost.
During mechanical design . of the sector magnet, wehave to be careful about difference between the calculation model and the real magnet. We started froma simple calculation model. For example, iron poles

23B U5B+ 150 MeV/nucleon

Original

\

>()
c:

ell
::I

0'

~
c:

e

1ii
Q)

method

.0

iii
()

1.43

ell

1.42

t

>

Iron plate method

1.41
1.40
1.15

1.20

1.25

1.30

1.35

Radial betatron frequency

Fig. 1. Influence of the magnetic shielding on betatronfrequencies.

were considered to be solid plates. The real iron poles,
however, have many holes and cuts for fixing the main
coil vessels, trim coil vessels, pole links and so on. It isdifficult to make a model which adopts all these withaccurate shapes because of limited node numbers of the
program by TOSCA.3) So, equivalent BH curves areused for modeling the holes of the iron pole. Figure 2
shows the regions used for equivalent BH curves in theiron pole. In these regions, new BH curve is calculated by taking the volume ratio of the iron to air into

r;'150.0I

Ie link screws
r;'100.0

L!-150.0- 1200 .0-)...Z200.0

1"-100.0

Holes for thel.Z250.0/"V-150.0/

I

Fig. 2. Calculation model of the iron pole. In hatched regions, equivalent BH curves are used.

197

account.
Figure 3 shows a model of iron yoke of the sector magnet . Holes of Fz supports and holes ofr'300.0

position monitors are considered for the iron pole.
The BH curve is also important to decide the structure of the magnet. Iron which has high saturation
magnetic flux will reduce the vertical betatron frequency as well as the excitation current.
The final structure of the sector magnet will be determined soon to satisfy the condition that the minimum value of the vertical betatron frequency should
be larger than 1.05 and that the maximum should besmaller than 1.5. This adjustment can be accomplishedby changing the cross-sectional size of the upper andlower yokes.
References

Fig. 3. Calculation model of the yoke.

1981) T. Mitsumoto et al.: Proc. 12th Int. Conf. on Cyclotrons
and Their Applications, Caen, to be published.
2) J. Onishi et al.: RIKEN Accel. Prog. Rep. 32, 205(1999) .
3) Vector Fields Limited, Oxford, England.

RIKEN Accel. Prog. Rep. 32 (1999)

Beam Optics Study on Single-Turn Extraction for RIKENSuperconducting Ring Cyclotron
J.- W. Kim, T . Mitsumoto, A. Goto, and Y. Yano
Beam dynamics has been examined for the RIKENSuperconducting Ring Cyclotron (SRC) to assess the
single-turn extraction. In fact, evaluations on optics in
the SRC alone can not assert a full assessment because
optics calculations are made upon rather idealized conditions, and because the SRC is a high-energy end of
the accelerator chain so that instabilities in a preceding machine will affect on the extraction. Nevertheless
it is essential that a single turn extraction is assured
for the SRC in terms of beam optics. The last-turnseparation should be sufficiently larger than the beamwidth, and the beam quality should be well preserved
throughout the acceleration. Usually, the turn separation is enhanced by off centering the beam. The beamin the SRC is to be off-centered at injection.
Design particle is the 0 7 + accelerating from 127 to
400 MeV lu because of its largest turn number i.e. thesmallest last-turn separation. The last-turn separationis plotted in Fig. 1 as a function of the energy gain
per turn (~E) when the turn separation is determined
only by the rf acceleration, and when enhanced by theoff-centering injection, which induces a precession. A
larger amplitude of precession can be induced with alarger ~E.

,.....

I

14

E 12E

/

......... 10c
0

~

0

8

Accel.

\....

0
0..

I

+ Precession

6-

Q)

(I)

C

4

~
Acceleration only

\....

::::l

r- 2
0

I

1.0

1.5

,
2 .5
2.0
~E (MV /turn)

-94
-9S
-96
=i

~ -97

cl::

.,
,
',>

-98
-99
-100
497 498

401
t-

.-

400

~

~399-

~

>

:~

2-398

---.

>,

01

~ 397

i

"

w

499 SOO".......

396

"

501

S02

395 -t-----r---.---,---...-j-r
70 80
90 100 110 120

r (em)Il¢ (degree)

Fig. 2. Phase space motion of the last five turns in thetransversal and longitudinal phase spaces.
width is assumed as 20°. The energy gain per turnis 1.6 MV which is obtainable when three rf cavities are arranged. If four cavities are employed, theminimum last-turn separation increases from 8 mm to
11 mm, while other beam behaviors remain essentiallythe same. By adopting a third harmonic fiat-topping
cavity the phase acceptance is larger than 20°, so thatthe beam phase width can be widened to lessen longitudinal space-charge forces.
A major resonance to affect the beam quality is
Vr =1.5 for the light nuclei accelerating to 300400 MeV lu. The gradient of the third harmonic field
causes the resonance in lowest order, and its constantfield component in the next lowest order. The static
phase trajectories are plotted in Fig. 3 below and above
the resonance. The eigen-ellipse changes its shapeat traverse of the resonance. As a result, the beam

tt-

3.0

Fig. 1. The turn separation at extraction versus the energy
gain per turn when the beam is injected centered (acceleration only) and off-centered (accel. + precession).
The orbit tracings have been carried out using theparticles randomly distributed in a 4-D phase space involving longitudinal and transversal phase spaces. The
vertical phase space is not included because the effects
on beam behavior by coupling to other phase spaces
are considered to be weak. Figure 2 shows the last
five turns prior to the extraction with 200 particles
tracked. The transverse emittance is 3.4 7r mm·mrad,
the energy spread is ±0.05%, and the initial phase

15

15

10

10

5

5

E

E

~

~

0

ct

0

ct
-5

-5

- 10

-10

-15 -t--,--,--..,-----r--,,---'f-

4S4 455 456 457 458 459 460

r (em)

,

456

458

460

462

r (em)

Fig. 3. Static phase-space trajectories below and above
the resonance shown in the left and right hand frames,
respectively. Beam energies of the 0 7 + are 306 and308 MeV ju, where the tunes are 1.496 and 1.503, respectively.
199

phase space becomes mismatched, by which the effective beam width broadens. When the error of field
gradient is 0.4 gauss/ em, the phase space motions near
the extraction will become the like displayed in Fig. 4
when the beam at the injection is centered without
precession and off-centered with precession. The phase+-96~-----L----~----~------L---__

witho ut precession- 98 -,--.., "'-;-

space oscillates due to a mismatch with a new eigenellipse after traverse of the resonance , and the last-turnseparation can not be effectively enlarged even with
off-centering. The gradient error allowable is thus considered to be below 0.1 gauss/em under a conservative
estimation.
The limiting current due to longitudinal spacecharge forces has been evaluated using a uniform ellipsoidal beam charge distribution. The electric fieldat the azimuthal edges of the beam is then given byl)pa

Eo=-g,
2Eo

0-100
::J

~
x
Q

-102

-104

-106~-----r-----.-----.------.-----+

496

497

498

499

R (em)

SOD

501

Fig. 4. The phase space motions near the extraction radius
when a third harmonic field gradient is 0.3 gauss/cm,
with and without an off-centered injection. Due to amismatch with a new eigen-ellipse above the resonance,
phase ellipses oscillate.

200

(1)

where a is a half of the beam vertical width, 9 is a form
factor, and p is the charge density. For 0 7 + beam, a isroughly 0.25 em, and 9 is 1.4. At 1 pp,A of beam current, Eo is calculated to be 9 V /m near the extraction.
The energy spread accumulated throughout the acceleration is about ±54 kV /u. Upon orbit tracings in a
4-D phase space such as shown in Fig. 2, the last-turnseparation disappears by ~E / E of about 2 x 10- 3 evenwith an off-centered injection. The limiting current isthen calculated to be 10 pp,A assuming that the initialenergy spread is ±5 x 10- 4 .
References
1) W. Joho: Proc. 9th Int. Conf. Cyclotrons and Their
Applications, p. 337 (1981).

RIKEN Accel. Prog. Rep. 32 (1999)

Design and R&D Works for SRC Sector Magnets
T. Kawaguchi, H. Okuno, A. Goto, J. Ohnishi, T. Tominaka, T. Mitsumoto, and Y. Yano
The RIKEN superconducting ring cyclotron, SRC,
has been started already in its construction.!} Six superconducting sector magnets 2 ) are one of the main
components of the SRC, and a prototype superconducting sector magnet 3 ) is now under fabrication. Figure 1 shows a cross-sectional view of the sector magnet, and a photograph of the main coil winding for the

prototype magnet is shown in Fig. 2. Main parameters of the sector magnets are following. The maximum
magnetic field in the beam orbit: 4.5 T, maximum operation current: 5000 A for the main coil and 500 A
for the trim coils, and the total weight of the six sector
magnets including yokes: 4300 tons. To avoid a coilquench, a cryogenic stabilizing method is applied to

FXSUPPORT
YOKE

COtDPOlE

I

I

MAIN COIL(super)& VESSEL

E

I/)

~

TRIM COIL(super)& VESSELz,
I- . ~-

Ix
I
I
MIC·3
I

~
MOC·3
7.75m

1.9Sm

BEAM CHAMBER& TRIM COIL(normal)

VACUUM VESSEL

Fig. 1. Cross-sectional view of the SRC sector magnet.

Fig. 2. A photograph of the coil winding for the prototype
sector magnet.

both of the main and trim coils. 4 )Design and R&D works completed and/or achieved
during 1998 are summarized as follows: (1) Detailed
design for fabrication of the cold mass (main and trim
superconducting coils, coil vessels, and cold-pole). (2)Mechanical and thermal analyses of the cryostat (vacuum vessel, thermal shield, and thermal insulating support system) and determination of their dimensions.
The detailed design work for their fabrication is undergoing. (3) Detailed configuration and dimensions of
the yoke. Effect of iron purity of yoke material on themagnetic field was investigated. Pure iron as the material for the yoke is being ordered for its fabrication.
(4) A design review meeting for the sector magnets washeld for 3 days in April '98 by an international technical advisering committee (TAC) which consisted of201

four experts on superconducting magnets. (5) A cooling system for the six sector magnets was redesigned
after a further study of the system's reliability referringto the TAC review. Two cold-box type arrangement of
the previous design 2) was changed to one cold-box typeto make the system simpler and less expensive. Figure 3 shows the cooling system diagram for the sector
magnets and for the active-shield-coils. Six sector magnets generate a leakage magnetic field in the areas not
only inside but also outside of the SRC-room. Therefore, a pair of superconducting active-shield-coils is being planned in order to minimize the leakage magnetic
field, especially in the outside area of the SRC-room.
Superconducting magnets for the injection and extraction beam channels of the SRC will be cooled down by
a separate cooling system. (6) The mechanical rigidityof the main coil was studied by measuring various small
straight coils (pack of wires and G II-spacers) and twocross-section-models. We found that the compressive
Young's modulus of the main coil is three to four times
lower than the calculated value which was obtained byassuming an ideal surface contact between wires andspacers. Compressive pre-stress for the main coil fabrication was decided to be 1 kg/mm2. (7) Mechanicalproperties of the AI-stabilized superconducting wiresuch as static strength, fatigue strength, and creep
characteristics were measured at room temperature
and at 78 K to investigate and confirm the mechanicaldesign. (8) Some important elements of the main coilvessels were mechanically tested at 78 K, and the results were satisfactory with our design. (9) Two crosssection-models, 1) based on the two different designs 3 )about the main coil/vessel configuration, were fabricated at Hitachi Ltd. and Mitsubishi Electric Corpo-

RIJP'IURE
DISK--- ------ - 8_. . ---MAIN
COMPRESSOR(oneil spair)------ - ------- --- _.-------. _ _ . __ .. - - --6 SECTOR MAGNETS

COlD-BOXACTIVE-SHIELD-COIL

Fig. 3. Cooling system diagram.

202

Fig. 4. A photograph of the one set of the 1/6-scale
Cu/lron magnets for the magnetic force measurement.

rations in order to assure the assembly process andto measure the mechanical rigidity. (10) Three setsof the I/6-size Cu/Iron magnets were fabricated, anda measurement of the unbalanced magnetic forces in
x , y, and z directions was started in December '98 andwill be finished in January '99. The magnets are cooled
down to 78 K to reduce the electric resistance of the Cu
coil, and excited by pulse for one to two seconds with adirect current generator which has a capacity of 750 V
and 5000 A. The maximum current density of the coilwill reach 200 A/mm 2. The coil/pole assembly unit is
supported by the yoke with the rods arranged in x, y,
and z directions, and magnetic forces exerted on thecoil/pole unit are measured by using strain gages on
the rods. The measured results will be compared withthe calculation results,2) and will be used to finalize
the designs of the prototype and six sector magnets.
Figure 4 shows the photograph of the one magnet on
a preliminary measurement test at room temperature.
(11) Protection analysis at coil quench was made,S)and effect of the eddy current in cold-pole due to achange in coil current is under study.
References
1) A. Gotoet al.: RIKEN Accel. Prog. Rep. 32,193 (1999).
2) T. Kawaguchi et al.: RIKEN Accel. Prog. Rep. 31, 208(1998).
3) T. Kubo et al.: RIKEN Accel. Prog. Rep. 31, 210(1998).
4) T. Kawaguchi et al.: RIKEN Accel. Prog. Rep. 31, 212(1998).
5) T. Tominaka et al.: RIKEN Accel. Prog. Rep. 32, 203(1999) .

RIKEN Accel. Prog. Rep. 32 (1999)

Quench Analysis for Magnet Protection of 'R IKEN
·S uperconducting Ring Cyclotron
T. Tominaka, T. Kawaguchi, J.-W. Kim, A. Goto, and Y. Yano
The quench characteristics of the superconducting
main and trim coils of the RIKEN Superconducting
Ring Cyclotron (SRC) ' were studied, using the computer program "QUENCH-M" which was developed on
the basis of the program "QUENCH" .1,2) In this calculation, it was assumed that the normal zone propagates
adiabatically and its shape is ellipsoidal. Since thewhole protection circuit of the superconducting main
and trim coils is complicated, the analysis of the magnet protection was made only for some simplified circuits.
The principal circuit diagram for the superconducting main coils of the SRC which consists of 6 sectors
can be divided into 2 sections in order to protect themain coil more safely during the quench without a violation of the balance of electromagnetic force (Fig. 1).

-

Ip.......

Ip - I

Rml--...

;-R;,.- -- •----_.•

Sector#l

Sector#3 Sector#S

Fig. 2. Protection circuit for the 3-sectorsuperconducting
main coils for the purpose of quench analysis.

:Ip

-

:Ip -

J:l

25

Rml

Rm1

-

---

J:l

Sector'1 Sector'3

-

:Ip -

:I2

12

Sectorll5 Sectorll2 Sectorll4 Sectorll6::_=__:::__:::_:::__ __ __5 _=-_ =-_ =-_=-_ ::.=-_.~__~~_~:=:_=-:=.:_=:-_~:-=_=-~_'=-~_~=-_~=-_:,..;:=-::,.:_=-~_:-~_

o~----~----~------~~~~--~~

123
I

Fig. 1. Protection circuit for the whole 6-sector superconducting main coils of RIKEN SRC.

Inductive coupling between the two sections (3 sector magnets per section) is small: namely the calculated value of the coupling constant is k = -0.034(without iron). As a result, it was confirmed that the
coupling effect is negligible in the quench characteristics.
Therefore, the circuit diagram for only the 3 sector
magnets as shown in Fig. 2 was analyzed extensively
for the purpose of protection of the superconducting
main coils. In this analysis, it was assumed that either
the upper or lower coil quenches.
Inductance of the superconducting main coil of
RIKEN SRC depends on the exciting current becauseof the presence of the iron pole and yoke. The nonlinear inductance depending on the current L(I) (=dE/IdI), can be calculated from the stored energy E.
The nonlinear inductance L(I) is shown in Fig. 3, together with two constant inductances Lo (dashed line)
calculated from the stored energy at I = 5 kA for thecase with iron, and Lair (dotted line) calculated for the

4

5

(kA)

Fig. 3. Inductance of the I-sector superconducting maincoil. The approximated nonlinear inductance, L(I), isshown by solid line; the constant inductance Lo for thecase with iron is shown by dashed line; and the constantinductance Lair without iron is by dotted line.

case without iron. It seems reasonable that the nonlinear inductance L(I) approaches Lair as the exciting
current increases.
The results calculated for three extreme cases areshown in Table 1 and in Figs. 4, 5, and 6. In thesecalculations, Run# 1 (black curve) corresponds to thecase with the nonlinear inductance and with the initial normal zone propagation velocity of Vi = 7.6 m/s;
Run#2 (gray curve) is the case with the constant inductance; and Run#3 (dashed curve) is the case with
Vi = 0.1 m/s. The calculated current decays shownin Fig. 4 are consistent with the expectation from theinductance and the total resistance, Rm1 + Rn (sum of
the dump resistor and the resistance of normal zone ofquenched coil). The time variations of the maximum
temperatures shown in Fig. 5 are also consistent withthe change expected from each current decay. The
203

Table 1. Calculated results of the quench analysis for the circuit shown in Fig. 2.
Run#
1
2
3

L

Rm'

(H)

(Q)

L(I) x 3
5.4 x 35.4 x 3

0.3
0.3
0.3

Vi
(m/s)
7.6
7.6
0.1

Tmax
(K)

140
140
300

Vmax
(kV)
1.5
1.6
1.5

L : Inductance of 3 sectors,
Rm' : Dump resistance,
Vi : Initial propagation velocity of normal zone,
Tm• x : Maximum temperature,
Vmax : Maximum voltage in the circuit,

6~--------~--~----~--~

VL.max
(V)

42
48
17

Eout
(MJ)
120
120
200

E in
(MJ)
87
85
0.72

Rn.r
(Q)

0.57
0.56
0.006

t.w

(s)
1.0
1.0
1.0

VL.max : Maximum voltage between layers,
Ein : Dissipated energy in the superconducting
coil,
E"tlt : Dissipated energy in the dump resistors,
Rn.r : Final resistance of normal zone, andtsw : Swich-off time of power supplies.

2r-----~--~----~--------~

1.75
..,
\
1.5
::'1.25 iI \ \ ~\

">

--5

~4

i
1 i

>

,~

'\

'
0.75 I~ 0.5 ii~~><

0.25 I

""

o

---

o

100

50

150

200

Fig. 4. Current decays of the superconducting main coilof the SRC during quench: black curve (Run#l), graycurve (Run#2), and dashed curve (Run#3) with dump
resistor of Rml = 0.3 n.
350~--~----~------~----~

300
Q' 250

".

".

I

200
>< 150
~ 100
50

/

E-i

/

o

50

100

150

200

250

Time (s)Fig. 5. Temperature rise of the superconducting main
coil of SRC during quench: black curve (Run#l), graycurve (Run#2), and dashed curve (Run#3) with dump
resistor of Rml = 0.3 n.

maximum temperature of Run#3 is equivalent to theso-called hot spot temperature. The maximum voltages during the quench shown in Fig. 6 are almost thesame to V max ~ 1.5 kV ~ Rml .10 , which is determined

204

50

100

150

200

250

Time (s)250Time (s)\"" . ___. _~ _________ _Fig. 6. Time dependence of the maximum voltage of thesuperconducting main coil of SRC during quench forthe circuit shown in Fig. 2: black curve (Run#l), graycurve (Run#2), and dashed curve (Run#3) with dump
resistor of Rd = 0.3 n.

by the dump resistor Rml = 0.3 n. For the smaller
dump resistor, Rml < 0.3 n, the calculated maximum
temperature reaches to a dangerous range hotter than
the room temperature. On the other hand, for thelarger dump resistor RmI > 0.3 n, the maximum voltage becomes too high to treat. Therefore, the dump
resistor of Rml = 0.3 n was chosen in Table 1 and in
Figs. 4, 5, and 6.
Furthermore, the quench analysis for system of themain and trim superconducting coils was also studied. The dump resistors of 5 trim coils are determinedso that the current will not increase when the power
supply is switched off after the quench of main coil. In
addition, effect of the cold iron pole as a secondary circuit for the superconducting coil system is to be taken
into account.
References
1) M. N. Wilson:
Rutherford Laboratory Report,
RHEL/M-151 (1968).
2) T. Tominaka et al.: IEEE Trans. Magn. 28, 727 (1992).

RIKEN Accel. Prog. Rep. 32 (1999)

Leakage Magnetic Field from RIKEN Superconducting
Ring Cyclotron
J. Ohnishi, T. Mitsumoto, A. Goto, and Y. Yano
When the light ions such as carbon are accelerated in
the RIKEN Superconducting Ring Cyclotron (SRC),
the axial betatron frequency decreases in the extraction side of the cyclotron, and approaches to the integer resonance at l/z = 1.0. 1 ) To keep the axial betatronfrequency away from the resonance, we need to havea strong inverse magnetic field in the valley regions sothat the edge-focusing force increases. Since the shapeof yoke of the sector magnet is designed according to
the above strategy, the SRC produces a large leakage
magnetic field around it.
The magnetic field strength is about 4 T in the beam
accelerating regions in the pole gap when the SRC sector magnets are excited at the maximum current. As
the area of the pole where these fields are induced isabout 7 m 2 , the total amount of magnetic flux is estimated to be 28 Wb per sector magnet. On the other
hand, as the area of the return yoke is about 6.5 m 2 andas the magnetic field strength there is 2 T due to themagnetic saturation of iron, the return flux becomes
13 Wb. Therefore, the magnetic flux of 15 Wb leaks
out from each sector magnet to its outside. This value
is nearly equivalent to the amount of the magnetic flux
to be produced by the coils.
Although there exists no law in Japan to regulate
the strength of the leakage magnetic fields, we set thefollowing two limitations:(1) The region where the strength of the leakage fields
is higher than 5 G should be restricted from entering.
(2) The strength of leakage field should be lower thanthe earth magnetic field (0.35 G) outside of the institute site.
The leakage fields from the SRC have to be shielded tosatisfy above limitations. One method is to cover thewhole room of the SRC with iron plates. Another isto place large Helmholtz coils around the SRC.
Figure 1 shows the distributions of the leakage fieldstrengths leaking from the SRC for the following threecases: (1) without magnetic shield, (2) with the passive shield to use iron plates, and (3) with the active
shield to use Helmholtz coils. These data were calculated with a three-dimensional magnetic field computation code "Radia". 2) In these calculations the magnetomotive force of the SRC is 5.3 MA turns per sector
magnet.
The shape of iron shield assumed for calculations isa cylinder whose diameter, height and thickness are

1000
~

0

015

0

..

n~O

100

No Shield
Shield wi th I ron Plates .
Shield wi th Coi Is, ..

.... " ......

V;

o~

10

0

I/)

:J

8
CD

0
0

N

0

I!I

0.1

0.01
10

R[m]

100

Fig. 1. Leakage magnetic field distributions (B z ) on
the median plane with and without magnetic shields
when the SRC is operated at the maximum current(5.3 MA/magnet). These data are calculated at the
points along the extension of the center line of the sector magnet. The abscissa indicates distance from thecenter of the SRC.

26 m, 12 m, and 16 cm, respectively. The total weightwas calculated to become about 2600 tons. On theother hand, the diameter of the Helmholtz coils is 24 m
and the distance of the two coils is 5.2 m. The magnetomotive force of the coils is 360 kA turns, and thetotal dissipation of electric power is anticipated to become approximately 1 MW if normal conducting coils
are used.
As shown in Fig. 1, the strength of the leakage field is
reduced to about one tenth of the case without shielding, and becomes smaller than the earth magnetic fieldat the distance of 40 m away from the center of theSRC.
We have decided to use the magnetic shield to use aset of Helmholtz coils because there are some difficulties in the construction of the building in the case of
the iron shield.
References
1) T. Mitsumoto el a1.: RIKEN Accel. Prog. Rep. 31, 206(1998).
2) P. Elleaume, O . Chubar, and J. Chavanne: Proc. 17th
Particle Accelerator Conference, in press.

205

RIKEN Accel. Prog. Rep. 32 (1999)

Analysis of. the Injection and Extraction Systems for RIKENSuperconducting Ring Cyclotron
S. Fujishima, H. Okuno, T. Tominaka, T. Mitsumoto, A. Goto, and Y. Yano
The injection and extraction systems for RIKENSuper.conducting Ring Cyclotron (SRC) had been designed as a three-RF-cavity system. I} But recently, toincrease energy gain per turn, the number of the RFcavities was changed from three to four. 2) To realize
the four-RF-cavity system, the injection and extraction systems should be changed significantly. Designof the injection and extraction systems is now morechallenging because the space to install the injectionand extraction elements has decreased.
The SRC has a strong stray field originated from thesector magnets, and this field depends non-linearly on
the magnetic rigidities of the beams. Thus, the trajectories of various beams differ considerably from eachother. Besides, the injection and extraction elements
should be installed in a small space limited with thesector magnets, RF-cavities, and vacuum chambers.
These difficulties make the design of the injection andextraction systems quite challenging.
Purpose of present analysis is to optimize the layout and specification of the injection and extraction
elements in the SRC. For optimization, the required
fields of the elements and the differences of trajectories in the elements are minimized.

To trace the beam trajectories, an equation of motion was solved with Runge-Kutta-Gill method. In thecalculation, electric or magnetic field of each element
was superimposed on the field of the sector magnets
which was calculated with a three-dimensional computer code, "TaSCA". 3)
Table 1 shows the energies and magnetic rigiditiesof three typical beams. The beam of 16 0 7 + (1) has
the smallest magnetic rigidity. On the other hand,the beam of 238U58+ has the largest one. Between
these two beams, the difference of trajectories is mostpronounced. The beam 'of 16 0 7 + (2) has the largest
Table 1. Energies and magnetic rigidities of three typicalbeams.

16 0 7+ (1)16 0 7+ (2)238 U 58+

Energy [MeVlu]
Inj.
Ext.

Inj.

Ext.

74.2
126.7
58.0

2.89
3.83
4.57

4.90
7.25
7.52

200
400
150

Fig. 1. Schematic layout of the elements, and the trajectories of typical beams.

206

B P [Tm]electric rigidity.
Figure 1 shows a schematic layout of the injectionand extraction elements, and shows the tr'ajectories of
two typical beams of 16 0 7 + (1) and 238U58+. Because of the stray field in the valley, two trajectories differ considerably from each other. The injection system consists of four bending magnets (BMl,BM2, BM3, and BM4), 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), andan electrostatic deflection channel (EDC). The beams
from a pre-accelerator are introduced crossing the EIC
and EDC, so that the EIC and EDC should have holes
to pass the beams. All MICs and MDCs are installed
between upper and lower main coils of the sector magnets. And each magnetic element consists of main
dipole coils and compensation coils to suppress fringe
field on the first or the last equilibrium orbit.
Table 2 shows specification of the injection elements.
Required magnetic field of the MICI has increased toalomost twice that in the case of previous three-RFcavity systE1m. , Table 3 shows specification of the extraction elements. Length of each element was determined inconsideration of the balance between the difference of trajectories in the element and the required
field of the element.
Further optimization is in progress.

Table 2. Specification of the injection elements.
Radius
[em]
EIC
MIC1
MIC2
BM1
BM2
BM3
BM4

Angle
[deg.]

000~4280 variable

108.5
96.0
132.0
132.0
466.8
240.8

53.2
72.0
52.0
42.0
5.0
14.5

Length[em]

BorE
maximum

102
101
121
120
97
41
61

110 kV/cm
0.32 T
1.12 T
4.36 T
3.64T
0.50T-0.91 T

Table 3. Specification of the extraction elements.
Radius[em]

Angle[deg.]

1691 ~4405 variable
EDC
MDC1
185.0
30.0
MDC2
190.0
37.7
221.0
MDC3
32.0
EBM1
595.0
6.0
EBM2
170.0
54.4

Length[cm]

BorE
maximum

213
97
125
123
62
161

-110 kV/cm-0.15 T
-0.27 T
-0.97 T
-0.32 T-4.20 T

References
1) S. Fujishima et al.: RIKEN Accel. Prog. Rep. 31, 214(1998).
2) A. Goto et al.: RIKEN Accel. Prog. Rep. 32,193 (1999).
3) T . Mitsumoto et al.: RIKEN Ac'cel. Prog. Rep. 32, 197(1999) .

207

RIKEN Accel. Prog. Rep . 32 (1999)

Design of the RF Resonators for the New
Booster Ring Cyclotrons
N. Sakamoto, O. Kamigaito, T. Mitsumoto, Y. Miyazawa, T. Chiba,
H. Okuno, A. Goto, and Y . Yano
The new booster ring cyclotrons IRC and SRC in the
RI Beam Factory require their acceleration resonators
to operate with a wide frequency range from 18 to38.2 MHz in the case of harmonic number 6. It is alsoneeded to obtain a large gap voltage around 600 kV at
38 MHz.I)
The present design of the acceleration resonator is

6 onuna single-gap type whose structure is basically same asthat of te RCNP(Osaka Univ.) ring cyclotron. 2 ) An
effort has been made to modify the frequency range ofthe former design from 23 to 46 MHz1) to the new operation range from 18 to 38.2 MHz. Schematic drawingsof the new design are shown in Fig. 1. The sizes of theresonators have become larger than the former ones .
. RF characteristics of the new resonators have been
investigated by using a three dimensional RF calculation code, MAFIA.3) A brief summary on the RF characteristics of resonators with the tuning panel angles of
0° and 90° are shown in Table. 1. The maximum powers for the IRC and the SRC resonators are estimatedto be 90 and 50 kW /resonator with a peak voltage of
0.6 MV /gap, respectively, at the highest operationalfrequency of 38.2 MHz.
The maximum acceleration voltage is anticipated toTable 1. RF Characteristics of the acceleration and flattop
resonators for SRC and IRC.
flattopresonaotrs

SRC accel.

IRC accel.

tuner position

0°

90°

0°

90°

1210 mm

1l0mm

17.3

38.4

17.95

38.7

53.7

118.4

(17.8)(39.0)b) IRC Acceleration resonator
fo [MHz]

650=

1800=

1350mmRs [MOl

0.52

2.12

0.69

2.48

0.87

0.72

Q

27000

37000

29000

37000

30000

28000

3800nun
75nun

-It-

Date in ( ) were obtained from the measurement with 1/10 scaled model.

§

~ ~

0

~

00

~\D

~ !§§
200nun

/////
/////

/////
/////

I

/////

/////
/////
/////

/////
/////
/////
/////

/////
/////

,.

/ / /////~~~~c) FLATIOP resonator~j ~~3550nun/ / " /'/////~~~~~r---"'---'////,.
///,./

/////
/////

,./,. / /////,.
//,./////////,.//

/////
/////

~~~~~f------I////,.
/////

350nun

2400nun!~:~~:9i

[Ell

1.0

2.0

.....................u..L....'---'----J'mFig. 1. Schematic drawings of the acceleration and flattop
resonators.

208

Fig. 2. Flexible panels are used to make contact between
the wall and the tuning panel.

be restricted mainly by cooling problem at the flexible
panels which are installed to make an electric contact
between the tuning panel and the wall (Fig. 2). The
power loss limit at the flexible panel is 4.7 W / cm 2
which corresponds tothe current density of 100 A/cm
at 100 MHz. In the acceleration resonators, the wallloss at the root of the tuning panel is rather large.
From the MAFIA calculation for the SRC resonator,
the maximum power loss at the flexible panel is turned
out to be 0.4 W /cm2 at 38 MHz with the gap voltageof 600 kV.
In order to find the accuracy of the resonant frequencies obtained from MAFIA calculations, a 1/10
scaled model of the SRC acceleration resonator wasconstructed (Fig. 3). The model was made of woodN~.......

i400~

j----------------~~ 82 MHz
!

>t
()

~

OJ

..

300

&
OJ

-,.'

H

~

200

i

(390 MHz)•.

, , ......

.IJ...... .. '

N"'"

I,

,-,-

"

I, ,.,.'".""i_! ""( 1 7 8 MHz)!

180 MHz,-----------------:

o

20

40

60

80

Panel Angle [deg.]
Fig. 4. Measurement of the resonant frequency with the
1/10 scaled model.

less than ±5.0 MHz which corresponds to ±500 kHz
for 1/1 scaled cavity. As shown in Fig. 3, the resonant
frequency is quasi-proportional to the tuning panel angle. The resonant frequencies at the panel angles of 0°
and 90° are well reproduced by the MAFIA calculation with an accuracy of a few percent (see Table 1).
The test with the 1/10 scaled model demonstra:tes thereliability of the MAFIA calculation for this structure.
The details of the dimension will be determined fromthe result of the calculation. Further investigation on
the feasibility of our RF system will be made by using
a 1/5 scaled model which is now under construction.
The size of the inductive coupler will be determined byusing the 1/5 scaled model.
Fig. 3. Photograph of the model of the SRC acceleration
resonator. 1: tuning panel, 2: Dee,3: feeder,4: pickup.

boards covered with an aluminum foil with a thicknessof 15 j.Lm. The resonant frequencies were measured byusing a network analyzer for the tuning panel angles
of 0° to 90° with a step of 15° (Fig. 4). We estimatedthe error due to a misalignment of the tuning panels and/or due to a deformation of the cavity to be

References
1) N. Sakamoto et al.: RIKEN Accel. Prog. Rep. 31, 222(1998) ,2) T . Saito et al.: Proc. 12th Int. Conf. on Cyclotrons andTheir Applications, Berlin, 1989, p . 201 (1989).
3) The MAFIA collaboration, User's Guide MAFIA Version 3.2, CST GmbH, LauteschagerstraBe 38, D-64289,
Darmstadt, Germany.

209

RIKEN Accel. Prog. Rep. 32 (1999)

Vacuum System for RIKEN Superconducting Ring Cyclotron
K. Sugii, K. Ikegami, s. Yokouchi, A. Goto, and Y. Yano
In this report, we describe the current design ofthe pumping system for beam chamber and other vacuum chambers of the Superconducting Ring Cyclotron(SRC).l) Aiming at a beam transmission over 99% for
all the ion beams available in the SRC, we have estimated the required pressure of a beam chamber fromthe relationship between the pressure at beam chamber and the beam loss which is caused by a change ofcharge state due to collisions of the beam against residual gas. 2 ) The result shows that the pressure at thebeam chamber should be reduced down to the order of
10- 6 Pa in order to restrict the beam loss within 1%
for very-heavy ions. On the other hand, it is presumed
that the outgassing rate for the materials exposed tohigh vacuum is very high since the bake-out of vacuum chamber will not be carried out. The vacuum
chamber of the SRC consists of six sector-beam chambers, four rf cavities, one unit of flattop cavity, andone unit of valley chamber. Table 1 shows the total
volume of the vacuum chamber and the surface areasof main materials exposed to high vacuum. In order toachieve the required range of pressure described above
as quick as possible, we are planning to use sixteen
cryopumps with a total pumping speed of 150 m 3 /sec
as main pump.

CPi and CP2: cryoPulIg. TI4': turbo-molecular PUIIg
RPi and FF2: rotary pump. PEP; roots pump
IV: isolation valve lair operated)

Table 1. Total volume of the vacuum chamber and thesurface areas of main materials exposed to high vacuum.

397 m

Copper

572 m

2

FPM (O-ring)

5 m

2

Chamber volume

85 m

I><l a ir operated va 1ve

Fig. 1. Pumping system for the vacuum chamber of the SRC.

210

3

Figure 1 shows the pumping system for the vacuum
chamber of the SRC. The pumping system consists of aroughing system, a high vacuum system and an ultrahigh vacuum system. The roughing system is composed of a roots pump of 2600 m 3 /h and a rotary pumpof 290 m 3 /h. This roughing system is installed at theflattop cavity and the valley chamber. The high vacuum system is composed of a turbo-molecular pumpof 5.5 m 3 /sec and a rotary pump of 155 m 3 /h. This
high-vac system is installed at each rf cavity. The
turbo-molecular pump of high-throughput type is to
be used. The reason for it is to shorten the pumping
time prior to the ultra-high vacuum system by switching the pumping system from the roughing system to@ cold cathode gauge ® hot cathOde gauge IB-A)@ mass spectrometer@ pirani gauge® pressure swi tch

2

Stainless steel

the high vacuum system at a higher pressure (about
70 Pa). If the ultra-high vacuum system starts to operate at the pressure of 1 x 10- 3 Pa, the total pumping
time during the operation of the roughing system andhigh vacuum system is calculated to take about 9 hours(from the atmosphere to 1 x 10- 3 Pa) .
The ultra-high vacuum system deploys 16 cryopumps: fourteen of 10 m 3 /sec and two of 5 m 3 /sec.
The two cryopumps of 5 m 3 /sec are installed at theflattop cavity and those of 10 m 3 /sec are distributed
to be installed at the valley chamber and to all of therf cavities. We chose cryopumps as the main pump of
ultra-high vacuum system, for they have large pumping
speeds against the water vapor and hydrogen gas , bothof which are predominant residual gas components inan unbaked vacuum system. Furthermore, they canbe operated even in a large environmental magnetic
field. Total effective pumping speed of the cryopumps
is about 66 m 3 /sec at the beam passage. By using thispumping speed and the published data for outgassing
rate of materials, the pumping-down time to achieve
the order of 10- 6 Pa is estimated to be more than afew hundred hours.
An isolation valve is installed between the cryopump

and the vacuum chamber, so that the maintenance foreach of them can be made independently. The isolation valve is required to be compact since the space
available for its installation is extremely limited. We
are currently making trial of a manufactured valve.
The pressure of the vacuum chamber of the SRC
will be measured with a nude type of hot ion gauge
during a shutdown period of the SRC. During the SRC
operation, since a hot ion gauge is of no practical use
due to a large leakage flux from the sector magnet,
we are supposed to use a cold cathode gauge. Being
constructed with a permanent magnet, it is expected
to be usable even in a large external magnetic field.
Measurement of pressure using a cold cathode gauge
under an external magnetic field is actually reported. 3 )We are currently investigating the effect of an external
magnetic field on a cold cathode gauge.
References
1) A. Goto et a1.: RIKEN Accel. Prog. Rep. 32,193 (1999) .
2) K. Sugii et a1.: RIKEN Accel. Prog. Rep. 31,224 (1998).
3) N. Yasumitsu: Proc. 8th Meet. on Ultra High Vacuum
Techniques for Accelerators and Storage Rings, KEK,
p. 75 (1992).

211

RIKEN Accel. Prog. Rep. 32 (1999)

Development of ACR Electron Cooler (1)T. Tanabe, K. Ohtomo, T. Rizawa, and T. Katayama
An electron cooler (EC) has been proven to be oneof the most effective devices to reduce the phase spacevolume of charged particle beams in the accelerators.
A scheme of adiabatic transverse expansion 1) has beenchosen for the Accumulator Cooler Ring (ACR) cooler
to further reduce the electron transverse temperaturethan a normal configuration. It is well known that the
average transverse energy of the ensemble of electrons
divided by the axial magnetic field is adiabatic invariant:<E..L> IB = const.
Therefore, by changing the strength of solenoid fieldfrom the gun section to the interaction region adiabatically, where the length of field change is much larger
than electron's gyration radius, the transverse temperature of the electron beam could be reduced by a factor
of Bf/B j • Here, the subscript f indicates the final value
and i the initial value. The electron kinetic energy Ec
can be determined by the nominal energy of the ion
beam E j according to the following relation:(1)
where Ce = 0.511 MeV and Cj = 931.501 MeV lu. The
ion energies in ACR vary from 60 to 400 MeV lu, whichtranslates to the electron energies from 30 to 250 ke V
to cover the entire range.
The beam diameter of 50 mm is derived from therequirement to cover the horizontal size of ion beams(maximum emittance of 1257r mm·mrad and horizontal betatron function of 4.34 m). An axial magnetic
field of 0.2 T is chosen to satisfy magnetization condition for the lightest ions. The expansion factor of
25 corresponds to the field of 5 T in the gun section.
The maximum available current is determined by theperveance of the gun which is fixed by the geometry
and extraction voltage, and it is practically limited by
the electrical discharge limit. In our case the electron beam current of 4 A is considered to be viable.
Length of the cooler is 3.6 m within ACR perimeter of
168.48 m, which translates to the relative cooler lengthof 0.02136. Other pertinent parameters are summarized in Table 1.
The result of our initial investigation of the electron
Table 1. Other ACR-EC parameters.
Toroidal angle/radius
Field uniformity
HVPS stability
Collector efficiency
Betatron tunes
Beta functions at EC

212

90 0 /1200 mm
0.2% (gun)/±5 x 10 ·4±1 x 10 . !J
> 99.98%
Qx = 4.555, Qy = 3.540{3x = 4.339, (3y = 3.281 [mJ

gun with the adiabatic beam expansion scheme has
been reported elsewhere. 2 ) Currently, a new design ofthe gun and accelerating tube is being investigated toreduce the bore radius of a superconducting solenoid
surrounding the gun section. The collector design has
been chosen similar to the one used for TARN-II withsome modifications to accommodate the higher beam
current and more vacuum capability. The designs ofshakers and clearing electrodes are underway.
Effects of the main solenoid on ion beam have beenstudied using MAD 3 ) program. A toroidal field has
to be approximated by the combination of 'thin lens'
kicker fields (H& V) and two effective solenoid fields on
both sides with following relations:

B(R) = BoRol R; R = Rol cos ¢,(2)

BI/ = B(R) . cos ¢; Bh = B(R) . sin ¢,(3)

s = s(¢o) - R o ' tan¢,

(4)

1
fO
BoRo
8 s = Bp . }e/Jo B h · ds = 13P¢o,

(5)

BoRa
8 h = - l3Pln(cos ¢o),(6)(BP) e81/ = (B ) . tan ¢o·

(7)

P wn

Here, ¢ is the angle from the center of the toroid and¢o is half the toroidal angle (45 0 ). Bo is the solenoid
field strength and Ro is the toroidal bending radius.
Table 2 summarizes the configuration of the magnets
used in the simulation.
Table 2. Configuration of the magnets for CSs and kickers.
ELEMENT
CSOL
OCSOL
SOl
00S2
BM
0022
CHK2
0022
QF
001
QO
OSOL
CVKl
CHK2
OSOL
TSOL2
SOLVK
SOLHK
TSOLI
SOLO

LENGTH[MJ
Variable
0.15
0.1
0.35
1.896
0.3
o (0.2)
0.3
0.4
0.2
0.4
0.5
o (0.05)o (0 .2)
0.5
0.6
0
0
0.6
1.8

B FIELD [TJ- 0.2*1.37124

ANGLE

1.5

22.5deg(0.254)7.02mrad10.32T /m-1O.73T/m( -0.0348)( -0.67)-0.24mrad-18 .50mrad

0.2*0.6435
0.24mrad11.48mrad
0.2 *0.9273
0.2

Compensation solenoids (CSs) are located in the adjacent straight sections. Correction kickers are placedin the same straight section as the main solenoid. Single particle tracking with 20000 turns was conducted
for each case. The observation point is at the centerof the main solenoid. The results are summarized inTable 3, which indicates that the vertical beam sizewith the presence of the main solenoid increases bymore than a factor of two, without any compensation.
(Figs. 1 and 2)
The result of a tracking with correction kickers andCSs is shown in Fig. 3. The vertical beam size has
been reduced close to the value without the EC. The
integrated field of the solenoid for this case turns out
to be half a value, which the calculation from Eq. (2)(7) implies. The reason for this discrepancy is deemedin the following: The calculation assumes that all thecompensations are done in the same straight section.
However, in the tracking, CSs are placed in the adjacent straight sections. Therefore, the uncompensatedbeam experiences quadrupole and dipole fields which.OJ50:§: .0125
.....

.OJOO
.0075
.0050

Fig. 2. A single-particle tracking result after 20000 turns
with main solenoid, but without any compensation.

Table 3. Ion beam size with varying CS field.
Integrated compensation
solenoid field (T)No EC (Fig. 1)o (Fig. 2)
0.25*2[mJ*0.274[TJ
0.5*2[mJ*0.274[TJ (Fig. 3)
0.75* 2[mJ*0.274[TJ
1.00* 2[mJ*0.274[TJ

Beam size in
X (mm)
23.5
25.0
24.0
23.5
24.0
23.7

Beam size inY (mm)
6.0
13.2
10.0
6.5
7.8
11.5

.006

:§:

.....

Fig. 3. A single-particle tracking result after 20000 turns
with main solenoid, compensation solenoids, and correction kickers with proper strengths .

modify the dynamics of beam before entering a CS.
Further investigation on the subject is being undertaken at present .
We have not ruled out the possibility to modify thelattice of ACR to accommodate EC, correction kickers,
and CSs in one straight section. In this case, use of
superconducting solenoids for CSs is contemplated.

.005

.004
.003
.002
.OOJ
0.0
-.OOJ

-.002
-.OOj

References

-.004
-.005

-.~

. x(in 5

Fig. 1. A single-particle tracking result after 20000 turns
without main solenoid.

1) Y. N. Rao et al.: Electron Cooling at ACR 1996, Proc.
EPAC '96, p. 1182 (1996).
2) 1. Watanabe et al.: Electron Cooling at ACR in MUSES
Project, Proc. EPAC '98, p. 2258 (1998).
3) MAD program, version 8.22., copyright by CERN.

213

RIKEN Accel. Prog. Rep. 32 (1999)

Design Study of Electric Power Station
for RIKEN-MUSES Project
S. Watanabe and T. Katayama
The accelerator complex of MUSES project comprises an accumulator ring (ACR), a booster synchrotron ring (BSR), and a double storage ring (DSR).
There are so many electric power supplies with an assumption of electric power up to 15 MVA.l) Considerable line impedance of AC power line branched under the electric- power company will bring unavoidable voltage drop not only at the accelerator complex
but also at experimental apparatus. A designed synchrotron power supply of BSR will induce both a large
reactive power and a higher ripple current because of
the 12-phase thyristor rectifier. 2 ) An energy bill relating with the operation of BSR will become a large partof considerable running cost. Thus, the design studyof site-specific power station is focused on a cleaned
AC power line, a good power factor, and an optimizedenergy bill. The present paper is concerned with theadvanced study of BSR power supply and with thebrief description of R&D relating with the switch-mode
power supply for the ACR lattice magnet.
The operating conditions of BSR have been studied
from the power supply point of view. The following
operating conditions fulfill the combination of different
ion species or of ion-electron acceleration: (1) Polarity
change is no longer required in order to inject different
ion species; (2) Pulse-to-pulse operation for different
ion species requires complicated current pattern control; and (3) Deceleration of an accelerated beam isrequired to decrease the radioactive contamination at

beam-damp courses. 3 ) Unfavorable remnant field due
to a hysteresis loop should be corrected for the dipole,quadrupole, and sextupole families. 4 ) An example ofthe measured hysteresis is shown in the literature. 5 )The result of analysis shows that the Fourier component of excitation pattern should be optimized since
the area of hysteresis curve is proportional to the repetition cycle of magnetic field as is well known. An
eddy current in the magnet gap and vacuum chamberof the ring gives an excess of sextupole excitation to
the beam optics. The tune tracking and chromaticity
control are influenced by the magnetic saturation effects. The study of BSR power supply will be focusedin the near future on those tricky problems.
By using the synchrotron power supply of the coolersynchrotron TARN-II, an R&D has been conductedaiming at the ripple reduction of BSR. The old DCCT
to have measured the magnet current was replacedwith HOLEC- DCCT. A normal-and-common mode
filter was installed in the line circuit of the dipole magnet strings. The new DCCT has the accuracy of 1 ppm
during the past one and a half years. The typical ripple
current measured by the new pick-up coil in the magnet gap was dramatically reduced by -40 dB comparedwith the original data. 6 )A line voltage fluctuation called flicker would be
deduced from the induced reactive-power due to thepulse operation of BSR. The site-specific power station is subject to stabilize the line voltage of RI-beamscorl. : Kglllm (torq)
KW ( p ....r)R.glRlg

Fig. 1. Flow simulation of the BSR power station.

214

factory, so that the interference between the electricpower line of BSR and the outside of BSR electricpower line should be minimized. Induced reactivepower is compensated with a hybrid power-saving system located in the BSR power station. The hybrid
power-saving system (HPSS) comprises a Static-VarCompensator (SVC) and motor- generator (MG) tostabilize the primary line-voltage of 6.6 kV and to suppress the 3rd, 5th, 7th and higher harmonic currents.
The dipole-magnet power supply is branched directly
under the HPSS. The power supplies of quadrupolemagnet group are branched under the HPSS throughthe sub-power station with local SVC.
The simulation of BSR power station has been
done with MATLAB. Figure 1 illustrates the MG
with flywheel system, BSR power supply model, line
impedance, and turn-on sequence with closed loop circuit.
MG-parameters were estimated as follows: The
power ratings of induction motor and AC generator
are 1.65 and 12.95 MW, respectively. The inertial moment of flywheel is designed at 7.2 [ton m 2 ] to achieve
the frequency stability of 0.5% at a rotation speed of
600 rpm. The dissipation of stored energy in the flywheel is illustrated as the sum of the negative energies
due to the apparent power of BSR. To shorten the calculation time, parameters in the flow simulation was
optimized. The examples of simulation are shown in
Fig. 2 and 3, respectively. Figure 2 shows the AC line

Fig. 2. Rise of AC line voltage after turn-on of MG system.

.
..
.

···
··

..
..

..

..

.
..
.
. .. ':. ... .. .:. . . .. . .. .:. ......... .... .. .. .
.
.
..
·
.
,
·
...
...
..
.
··
.
.
.
~

Fig. 3. Voltage drops of the MG output due to repetitive
BSR operation.

voltage after turn-on and continuous operation of the
MG system.
Fluctuation of the AC line voltage due to the repetitive operation of BSR is calculated as shown in Figure 3. The voltage drops due to the pattern operation
are seen in the figure . The apparent power of BSR is
calculated at peak.
The power line accident would occur due to any reason. The diesel engines would be used during the peakelectricity days to reduce the energy bill. The solutionof redundancy, adapted directly onto the 6.6 kV lineof the 10 MVA peak-power requirement, is a new wayof supplying electricity to all the sensitive equipmentsof MUSES complex. Thus, RI-beam factory considers the power plant that is composed of 2 sub units of
1 MVA, each connected in parallel in a N + 1 redundant way. The parallelism is performed at the 6.6 kVlevel. This means that the system is composed of two
6.6 kV bus bars one for the input and another for the
output. The motor generator mentioned above is mechanically connected to those diesel engines with themagnetic-crutch.
The design study of ACR magnet power supply has
been performed. The lattice structure of ACR is basedon the race-track FODO functions with a large beam
acceptance. A switching dc-power supply with power
rating of 20 or 2 KVA can be used to excite thequadrupole and sextupole magnets. Difficulty for themagnet power supply is to make the ripple field low as
required for the beam cooling experiments. Designed
switching regulator is described as follows: One ACDC converter and four inverters comprise a complete
unit of switching power supply. The AC-DC converterdelivers pre-regulated dc power to each inverter unit.
Each inverter unit is a pulse- width-modulation typeswitched regulator that is composed of insulated-gatebipolar transistor, coupling transformer, rectifier, andcurrent control loop. To suppress the ripple current,
the polyphase technique is applied to the inverter unit.
The normal and common mode filters are equippedin the polyphase inverter unit to suppress a ripple
current up to 120 KHz. The electromagnetic shielding is subjected to suppress the radiated electromagnetic field from the switching elements. The commonmode filter is equipped in the AC-DC converter to suppress the leak-noise entering into the primary AC lines.
A combination of the 12-phase thyristor rectifier andtransistor-type series dropper is considered as the ACR
dipole-magnet power supply.
References
1) T. Ohkawa et al. : Proc. EPAC98, p. 2123 (1998).
2) S. Watanabe et al.: Proc. EPAC96, p. 2340 (1996).
3) S. Watanabe et al.: Proc. EPAC98, p. 2082 (1998).
4) B. C. Brown et al.: FERMILAB-Conf-97/ 147 (1997).
5) S. Watanabe: INS-T-533, Accelerator-20 (1995).
6) S. Watanabe et al.: Proc. 11th JPAC, p. 101 (1997).

215

RIKEN Accel. Prog . Rep. 32 (1999)

Design of a Slow Extraction System at Booster
Synchrotron for MUSES
T. Ohkawa and T. Katayama
In Booster Synchrotron Ring (BSR) the accelerated
ion and electron beams will be fast extracted, and subsequently injected into Double Storage Rings (DSR)
by one turn injection. As an alternative mode of operation, the ion beam will be slowly extracted for theexperiments. In this paper the slow extraction procedure of ion beam at the BSR is presented.
For slow extraction process, firstly, the sextupole
magnets as a resonance exciter are excited. Secondly,
the horizontal tune is changed from the operating value
6.691 to a certain value near the third order resonance (20/3) by controlling the excitation currents of
the quadrupole magnets. Beams which have deviatedmore than 25 mm inside from the central orbit at theentrance of the electrostatic septum (ES) are deflected
inward as large as 3 mrad by the static high-voltage ofES.
The Hamiltonian can be expressed by the following
relation
H = _~(X'2 + y'2) _ f3gJ A2 + B2 (X'3 _ 3X'Y,2)
2
3Jl + Q2'

from which we can obtain following three unstable
fixed points:e~

A: (X' Y') - (l' 1 {3gJ A 2 + B2 '(_!x, -J3 x,)

C : ( X '3 , Y 3') =(1, 2J3 ,)

2

l'

-2X1'

2

.

Thansforming back to the (x, x') plane , we obtain thefollowing three unstable fixed points: l )( - G cos(1II - X),~ G cos(1II + X) )( - G cos ( III - X +

~

7r )

tanx=~-a216) )~1f) ,~ G cos ( III + X - ~7r
where

4

f3gv A2 + B2

The turn separation ~x during three turns can be derived from the Hamiltonian as follows:~x= [~+al~(~X'cosW-~Y'sin w)

J2+ [~- al~(~X'sin w+~Y'cosw)
where~X' == dX' = _ aH = eY' _ 2f3gV A2 + B2 X'Y'ay'~y' _ dY' _aH= dv - - ax'
dv

Jl + a 2= -eX' _ f3gJf'7A"""2-+--=B"2 (X,2 _ y'2).
VI +a 2

If we use two sextupole magnets as a resonance exciter,
their strengths are given bygl =(A2 tan 3w + B2)COS 3wJ A2 + B2
A2Bl - AIB2g

w = 32°
gl = 1.461 m- 3
g2 = -0.333 m -3.
Result of tracking is shown in Fig. 1, where the outgoing trajectory at the entrance of ES is different fromthat obtained by the theory.
We therefore tracked of the orbit with computorchanging W as a parameter, and chose the best strenghsof the sextupole magnets.

,~ G cos ( III + X + ~7r( -G cos ( III - X -e(l+a 2);!

But, there is a little difference between the separatrices obtained by the theory and the orbit tracked
with computor, because we take only one of the nonlinear terms which has the largest contribution to theresonance orbit.
For example, if we assume S to be 107r mm· mradand ~x to be 5 mm, we have 2 )

1

X1

G=

Altan 3w + Bl
g2 = - A 2tan 3w + B2 gl'

0)

B: (X'2, Y')
=
2

and

W = 29°gl = 1.166 m- 3
) ),g2 = 0.025 m - 3 .
Result of tracking is shown in Fig. 2, where the outgoing trajectory at the entrance of ES is very close tothat obtained by the theory.

PHASE SPACE
10

5

I

g.= 1.461 m-3
gz= - 0.333 m-30

Qx=6.675
Qy=6.212><

If the area of the triangular separatrix becomes
smaller, the particles with larger amplitude will reachthe separatrix to escape from the stable region. As
soon as single particle escapes from the stable region,
its amplitude will blow up rapidly along the out-going
separatrix, and will finaly jump into the gap of the ES.
The amount of reduction of the triangular separatrix
is given by-5
theorytracking

- 10
- 40

- 20

0

20

40

X[mm]

Fig. 1. The separatrices and outgoing trajectories at theentrance of ES (w = 32°).

which indicates that the extracted particle numbers
can be controlled by the phase shift E. We have calculated relation between tune and extracted particle
numbers. Result of the calculation is shown in Fig. 3.

1- -PHASE SPACE-COUNTS I

I-TUNEI

10

5
:0

6.676

500

6.674

400

6.672

0
300 c

6.67

200

6.668

100

gl= 1.166m-3

i 0

gl = 0.025 m-3~

Qx=6.615
Qy=6.212

-5
-10
- 40

theorytracking- 20

0
X [mm]

20

40

(')

~

;:>
f-o

~
Vl

~

6.666 .................................................................I...I..&...L.......~ a
0.06

0.08

0.1

0.12

0.14

0.16

0.18

TIME(S)

Fig. 2. The separatrices and outgoing trajectories at theentrance of ES (w = 29°).

Next, we calculate the number of extracted particles.
The area of the triangular separatrix in the (x, x ')plane is given by·
2X I ~G2
3v'3 sm
S = -4{31

3v'3 .

=

4(1 + a 2)22

1sm 2xI {33 2(A2 + B2) E .
g

Fig. 3. Tune and extracted particle numbers per second
vs. time for Gaussian distribution (Ap/p = 0).
We have found that a slow extraction of ion beam
can be carried out by using the third order resonance(vres = 20/3). This procedure needs to be investigatedfurther for the installation of all necessary hardwares.
References
1) Y. Kobayashi: Nucl. lnstrum. Methods 83, 77 (1970).
2) T. Ohkawa and T. Katayama: Proc. 6th EPAC,
Stokholm (1998).

217

RIKEN Accel. Prog. Rep. 32 (1999)

Ferrite Test Cavity for MUSESt
K. Ohtomo and Y. Chiba
In the project MUSES, it is urgent to develop a ferrite loaded cavity for the Booster Synchrotron Ring.
The cavity should operate with the frequency range
from 25 to 53 MHz, the voltage 25 kV per cavity, andthe repetition frequency 1 Hz. For this purpose, it isnecessary to meet the following characteristics of theferrite material: the relations between permeability (J-L)
and bias current, magnetic Q-value (Qm) and RF flux
density, and between high loss threshold 1 } and bias
sweep rate. Moreover, these measurements have to be
performed with the real size of ferrite and with real
RF power level of operation. We therefore designed
and manufactured a test cavity for investigating the
RF properties of ferrite. Table 1 shows the parametersof the test cavity.
Table 1. Parameters of the ferrite test cavity.
Cavity type
Frequency range
Ferri te size
Tuning elements
Bias conductor
Cooling of ferrite
RF source
Bias current
Impedance matching>../2 coaxial resonatorloaded with capacitor
20-60 MHz5" (I.D.) x8" (O .D.) x I" (thick)400 mm max. in O.D.
Bias current,
Variable capacitor
10 turns of watercooled hollow conductor
Water in cooling plate
A 3kW solid-state
wide-band amplifier
2500 A
Variable capacitor in series

Figure 1 shows a schematic drawing of the ferrite
test cavity. It consists of three coaxial arms: F, S, andC arms. The F and S arms are aligned in line andform a ),,/2 resonator loaded with a tuning capacitancein C arm. In order to operate under the above frequency range at high power and high loss threshold, awater cooled vacuum variable capacitor (30- 650 pF) is
employed. Ferrite is tightly in contact with the cavity
wall on both sides, and cooled through the wall by water. The size of. ferrite is fixed to be 5 inches in innerdiameter, 8 inches in outer diameter (O.D.) and 1 inch
in thickness. We can test another size of ferrite with
O.D. up to 400 mm by replacing the ferrite vessel.
Conductor for bias current are passing through inside the inner pipe, and wind ten turns around theferrite ring. The upper parts of conductor are removable for exchange of ferrite. Thus, RF power is confined in the cavity, and does not affect measurement
nor biasing system. A water-cooled hollow conductor
Condensed and revised from the article in Proc. 6th Eur.
Part. Accel. Conf., p. 1823 (1998)

218

Fig. 1. Schematic drawing of cavity. I-ferrite ring, 2-ferrite vessel, 3-tunig capacitor, 4-impedance matching
section, 5-bias conductor, 6-removable cross bar, 7-voltage and current monitor, 8-2nd voltage monitor, 9-RF
input terminal, and 10-water cooling pipe.
is used. Maximum bias current is set to be 2500 A.
Most of the material of this cavity including a fixedstub is aluminum except the cooling parts.
Impedance matching between 50 n RF source andinput impedance of the cavity is necessary to performthe test in high RF power level. Impedance conversion
to use a series of variable capacitor (6-500 pF) was
adopted. A current transformer and a voltage divider
are installed at the entrance of the matching section inorder to monitor the input impedance and input RF
power. The 2nd voltage monitor is located at the entrance of the ferrite vessel. Figure 2 shows calculated

30

40

50

60

70

Frequency [MHz]Fig. 2. Tuning capacitance and frequency at resonance.
Marks represent experimental data and solid line wasobtained by calculation without ferrite. Dashed lines
are by calculations with ferrite for different J.L as shownin figure.

tuning curves of the system, where a transmission line
calculation was used. Measured data on the empty
ferrite vessel are plotted by filled squares. Unknown J.L
can be determined from these tuning curves. For measuring Qm, input RF power and 2nd monitor voltage
are measured, which determines the shunt resistanceat the position of the 2nd monitor. Qm can be calculated from the shunt resistance after corrected with
contribution from the cavity system.
Test measurements of J.L and Qm were carried out

for the ferrite MIlE by TDK. It was clarified that thebias current of 1000 A (10000 A-Turns) is enough forthis ferrite to reduce the J.L to become 2 (Le., J.L = 2).
Tentative results are shown in Figs. 3 and 4.
An unstable contact was found at the contact fingers
used in the ferrite vessel. An improved vessel is being
manufactured.

11.5

180
160

D~

11.0

- . - 19.3-+25.0MHz- - 35.4-+67.9MHz

25

-0

140

700

{;)
20~~----+-----r---~~~-+----~~600

::1.

10.5

120 <
Q)

C

100 CD°- - 0 - -0
500
15r-~----+---~~~~-----+----~~

10.0

400 "

80

<
Q)

10~-r

__~+-----~--~-----+----~~300 C
CD

9.5

0

200

500

1000

1500

60
2000

Input power [W]

5~~--~~----~--~-----+----~~

100
1- 1= =1= 1
O~~~--~~--L-~~--~~--~-L~O

o

5000

10000

15000

20000

25000

Bias current [A Turns]

Fig. 3. Ferrite J.L and Qm as a function of bias current
under low power test. Filled marks are J.L and blankones Qm. Resonance frequency range are represented
in the inset.

Fig. 4. Ferrite J.L and Qm as a function of the dissipation
power at ferrite under high power test. Bias current is
20 A and resonance frequency is 28.6 MHz.

References
1) J. E. Griffin and G. Nicholls: IEEE Trans. Nucl. Sci.
NS-26, 3965 (1979).

219

RIKEN Accel. Prog . Rep . 32 (1999)

Simulation of Coherent Behavior of Electron-Cooled
Bunched Ion Beam at the Ion-Storage Ring of
RIKEN RI-Beam Factory Project
M. Takanaka and T. Katayama
lon-beam bunching under electron cooling was studied by using a computer simulation for realizationof the bunched beams required for collision experiments. The simulated results1) have predicted that(1) the beam has wide tune spreads longitudinally andtransversely, (2) the beam is not trapped into resonances due to the nonlinear fields of magnets, and (3)the beam is stable longitudinally under a broad-band
impedance based on the broad-band impedance model.
A 150-MeVlu u~~t -ion beam at 3.4 rnA has been
simulated, and has the profile shown in Fig. 1 under thefundamental-RF (h = 87) voltage 16 kV and the thirdRF-harmonic voltage 24 kV. Results of the coherent
behavior of the beam are reported here.
The beam has a maximum instantaneous current of 45 rnA at the bunch center.
The beamhas very wide incoherent tune spreads as shown in
Fig. 2, because of the intense, small-sized charge distribution which is not flat in the transverse directions and parabolic in the horizontal direction. The
spreads make synchrotron-tune multiples overlapped,and make the betatron and synchrotron tunes over-lapped at the betatron-side bands. This is why one
can not use the Sacherer method as a tool to predict
instability phenomena.
Following equations are used to describe the coherent behaviors of the longitudinal beam intensity
I and of the transverse dipole moment h (transverse
displacement x I):

I(t,s) = LAI(n , n)exp (-int+i";:) ,n,nII (t,s) = LAh(O , n)exp (-iOt+ir;:) ,n ,nwhere A is the amplitude of the component, t the time,s the longitudinal position, 0 the coherent frequency,n the oscillation mode along a ring, and R is the mean
radius of the ring.
The longitudinal spectrum of the coherent behavior, or A1(O , n) as shown in Fig. 3, has three kinds

Ampl itude

y(m)
0.01
0 .0075 + . .... " ........ .
0. 005 ~. .. ..... :" ......................................,........ ,....... ,.: .,..................................... .
0.002510
10o-0.0025-o~gn l :::::::::::::::::: ;:::~~.

10-0.01 t:===t==~4

x(m)

0 .1

-0.1

-0.2

0.2

z(m)

L

250

Fig. 1. Beam-bunch profile in the three-dimensional space.

:::

~
~

3000
;r>08

<U

2500
2000
1500

0:

1

~g~

j~

-I

L-=-:""'"_ - ' -_ _---'_ _ _--'--_ _

o

0.05

0.1

0. 15

---'~
0.2

Vs

4

5

v

6

7

8

Fig. 2. Tune distributions of 5000 particles.
220

Fig. 3. Spectra of the longitudinal and the transverse oscillations. The upper spectrum is for the longitudinaloscillation, which is normalized so that the DC component is 1. The lower spectrum is for the transverse
oscillation. The both spectra have the low signals cutaway.

of signals: a signal along ffjwo - n == 0 ' due to thelongitudinal parabolic charge dist~i.bution (monopoletype); signals along n/wo - n = ±1 due to the oscillation of the bunch length (quodrupole type) , whose
frequency is equal to the revolution frequency Wo in thecase where the RF cavities are installed at a position
along the ring; and signals around n/wo - n = ±1/2
(dipole type). No signal due to the synchrotron tune
is observable here, because of the overlap . .
The transverse spectrum, or Ah (0., n), has two signals of the fast and slow waves along n/wo - n = ±7.4.
Behavior of the bunch after shifting the bunch fromthe synchronous particle by 4 cm has been simulated
for the sake of checking the longitudinal stability. As
shown in Fig. 4, the longitudinal oscillation is seen
to be damped within several periods of synchrotron
oscillation.

3.5 10"6 :0~

1

1 10.6c:-2

5 10"7

;::l

co

c:

I

2

:eCl

0

....

-2

0-

11)

c:

11)
Co)

.c.

~

55

.___ 11 fi\\".........-..... .__ .................. _. _....... _...._....__. - .........
i

54
53

E
c:

:~o
...0-o

c:

;:l

-8 !
41.4

41.6

41.8
42
Time [ms]42.2i

2.5 10-6

g

2 10.6

.~

E

i

-1

1 10"6-a-2

5 10"7.~Co

3 10.6

1.5 10"6oL-_~_---I~_~_---I

41.4

41.5

41.6

41.7

_ _- L - _ - - - l 0

41.8

41.9

c:o

o
::t:

42

Time [ms]

~

.:::

00
c:

~

Co)

c:

;:l

co

-4

51

§

50

\0

Co)

co

2

E.

E

.:::

52

0

§

Time [ms]3 ,---....,-----,...-----,.----,---.---::.----, 3.5 10-6 :0c;l-3Center position

i.E-3 L-_~_---I_ _--l..-_--L_ _ - L - _ - - - l 041.4 41.5
41.6
41.7
41.8
41.9
42

co

I

1.5 10"6

-1

1:.
u

*'"'

E

o

u

::I

~

2 10.6c:oc:E

2.5 10.6:~o...0-o

u

56

1

c:

1:.
u
4 ;i

3 10"6

Fig. 5. Transverse oscillations. The upper figure is for thetransverse shift distance of 0.5 mm. The lower figure
is for the transverse shift distance of 2 mm. The thickcurves are for the emittance, and the thin ones for thecenter position.

*

49

Fig. 4. Damping of the longitudinal oscillations.

Stability of the transverse behavior of the bunch after its shift from the central orbit is seen to be dependent on the shift distance, as shown in Fig. 5. The
shift makes a dipole, or a pair of the dense and lightspaces in the transverse phase space. In the unstable case of the shift distance of 2 mm, the dipole isincoherently mixed and the dipole moment decreases
until 41.52 ms, but after then the dipole is coherently
enhanced. The transverse emittance increases simultaneously, as shown by the thick curve in the lower ofFig. 5.
The transverse results have been obtained by using

the transverse space-charge impedance model basedon the following transverse charge distribution of thedipole mode, p(r). The p(r) is more realistic than
the ring-type distribution on the assumption that thetransverse charge distribution of the beam is not flat
but Gaussian with the deviation a:p(r) = 2hn(r) cos 0,
where

r

(r2
)
20-

n(r) = - - exp - -2 .
47r0-4

References
1) M. Takanaka and T. Katayama:
Proc. PAC'97,
p. 1807 (1997); M. Takanaka and T. Katayama: Proc.
EPAC'98, p. 1014 (1998).

221

RIKEN Accel. Prog. Rep. 32 (1999)

Calculation of Single-Bunch Instabilityof Electron Beam at DSR
M. Wakasugi and T. Katayama
In the RI beam factory project,1) we will construct an accelerator complex, which is called MUSES
project. 2 ) At the double storage ring (DSR) in the
MUSES, we plan to make unique experiments such as
electron to RI collision and X-ray to RI collision experiments. This is why we have to store a high-quality electron beam with a large average current into the DSR.
Especially, for the X-ray to RI collision experiment,
the electron beam emittance should be on the order of
10- 9 m·rad to produce a high-brilliance soft X ray byusing an undulator. 3) Design of the DSR lattice 4 ) fora small-emittance electron beam may give us a serious
problem of the beam instability. We have to speciallycare about the instability to achieve the targeted current of 500 rnA in the energy range of 0.3-2.5 GeV. As
the first step to study the beam instability at DSR, wehave calculated the single-bunch instability caused bybroadband impedances for a small-emittance mode ofoperation of the presently designed DSR.
The calculations were performed in both the frequency domain and time domain using a computercode made by ourselves. Various sources of the broadband impedance and their values were referred tothoses of SPring-S 5 ); they are listed here in Table 1.
Instability calculation in the frequency domain is basedon treatment of the eigen-equation derived from wellknown Sacherer's equation:. m e2 wo <Po(0 - mws)Rm(r) = -1-/32ETor

L lex>
ex>m'=-ex>",Rm,(r )r dr i

~ ZL(w')
L-t -w-,-JmCw , r)Jm'(w , r),

m-m'

p=-oo

0

( 1)

for longitudinal oscillation and

Table 1. List of sources of broadband impedance.
Elements
Bellow
Taper
Vacuum port
Button electrode
FlangeWeldment
Valve
Space charge
Resistive wall

No.
50
2
90
20
300
200
30

ZL/n(Q)-0.637 i-0.0008 i-0.0027 i-0.076 i-0.003 i-0.0006 i
12/n - 0.001 i-0.0006 i
0.6(1-i)/;-nZT(MQ/m)-0.087 i-0.0001 i-0.0004 i-0.0103 i-0.0004 i-0.00008 i
14/n - 0.001 i-0.00008 i
0.08(1-i)/r n

Cavity2

8000(1+i)/nrn

1098(1+i)/nrnof excited m-th mode of instability. Assuming a Gaussian distribution for <po(r), we can express Rm(r) by theLaguerre polynomial Lh(R). Finally, these equations
reduce to an eigen value problem for the frequency
shifts.
For example, one of the results of frequency domain
calculation is shown in Fig. 1. This shows the eigen
values for modes m = 0, 1, and 2 as a function of theelectron beam current at the energy of 1 Ge V. The
mode coupling, which is a source of strong instability,
happens at the single-bunch current of about 0.77 rnA.
lt gives a threshold current of instability. In the sameway, we found that the threshold current is 6.6 rnA at
the energy of 2 Ge V. The threshold current depends
on the RF voltage, because the bunch length changes
by the RF voltage. Relation between the thresholdcurrent and the bunch length is shown in Fig. 2. Opencircles indicate the threshold current at each RF voltage. The threshold current increase with increasing RF
voltage. Its bunch length is, however, getting shorter
with RF voltage. This bunch shortening limits the

4 r-r-r-r-,....,.....,,....,.....,--r--r-,--,.---.,-:r-r~...,...-r~...,...-r~-r-r-.-,-.-r;•••;-r-'I

L io
ex>

Ee = 1 GeV[ ex>

m'=-ex>Rm,(r')r'dr'jm-m'

3

0
,

,

~ wO

,,~ wO ')ZT(w )JmCw r - -r)Jm,(w r - - r
1]

(2)

2

.......

1]p=-ex>

.....

.....

.........

.....

......

.....···"imaginary Part

for transverse oscillation, where w' = pWO + 0, Rm(r)is the radial part of the perturbed quantity <PI (r) of
the particle distribution <p(r) given by

.....

o

.....

-1
<per) = <po(r) + <PI (r) = <po(r) +L-t Rm ( r ) c im .p

'"""

(3)

m=-ex>

in the longitudinal phase space, J m is Bessel function,and the others are conventional notations. Solutions to
the frequency shifts O-mws and O-w/3-mw s are complex numbers; the imaginary part gives the growth rate222

-2 ~~~w-~~~~~~~~~~~~~~

0.4

0.6

0.8
1
1.2 1.4 1.6
Single bunch current [rnA]

1.8

2

Fig. 1. Eigenvalues of the longitudinal oscillation modes
as a function of the single-bunch current at 1 GeV.

also added as:

3
Be = 1 GeV

~ai=

2.5

S
~
-5
eJ)
s::

V.,"T€O- - V i e i2.w I

(7)

T{3

Transverse
Mode-Coupling

for transverse and

2

~

(8)

..r:: 1.5~=~

, ',,-- Long itudinal.,, Mode-Coupling

0.4 0.6

0.8
1
1.2 1.4 1.6
Bunch current [rnA]

1.8

2

Fig. 2. Bunch lengthening due to the potential-well distortion. The starting points of mode coupling are indicated by open circles together with lines for the guideof eyes.
possible maximum current. It is anticipated from thefigure that the maximum would not exceeded 1.5 rnA
for the case of 1 Ge V. That is about one order less thanour target current at 1 GeV. We found, however, thatthe upper limit of the current larger than the targetedcurrent can be expected at 2 Ge V.
Another approach adopted here is calculation in thetime domain. This calculation is based on the tracking calculation using equations of motion including the
wakepotential produced by a bunched beam itself at
the source of impedance listed in Table 1. We canmake relvant equation of motion for the betatron amplitude ai (B) as:

j=l

for longitudinal, where ~ T is the time advance, co theequilibrium emittance, TfJ the betatron damping time,
Te the synchrotron damping time, (J e the equilibrium
energy spread, Vi and Uj are the random number forming a Gaussian distribution with rms = 1, and Wi is
the random number forming a uniform distribution.
Growth of the amplitude (ai) at several bunch currents is shown in Fig. 3. The 0 mA means no wakefield; and in this case, the amplitude decreases due tothe radiation damping. In the case of 1 mA or 5 mA,
it seems that there is no positive growth. Over 10 mA,
especially for the case of 20 mA, however, it seems thatthe amplitude growth starts from about 8 msec. Thissituation may be made clearer by continuing the calculation for a longer time range. These results meanthat the threshold current is supposed to be at around
10 rnA.

Ee=2GeV
1.95 lO-4m=l1.9310. 4

for transverse andlO

Vo- To (1 + 20j},
dTi

17 hv

d8 = -R oi ,Fig. 3. Amplitude growth as a function of time .
(5)

for longitudinal, where N p is the number of particles ina bunch, Qj the charge of j-th particle, N z the numberof the source of impedance, and (Jm the beta function
at m-th source. The radiation damping effect has tobe taken into account as:(6)

where at is the amplitude of betatron oscillation at theentrance of the RF cavity. The radiation excitation is

References
1) Y. Yano et al.: Proc. PAC97, Vancouver, p. 930 (1997).
2) T. Katayama et al.: Nucl. Instrum. Methods Phys. Res.
A 626, 545c (1997).
3) M. Wakasugi et al.: Proc. PAC97, Vancouver, p. 3521
(1997).
4) N. Inabe et al. : Proc. PAC97, Vancouver, p. 1400
(1997).
5) T. Nakamura: Proc. EPAC 96, Barcelona, p. 1099
(1996).

223

RIKEN Accel. Prog. Rep. 32 (1999)

Design Study of Superconducting Quadrupoles
for RIKEN Big RIPS
T. Tominaka and T. Kubo
For the superconducting quadrupoles of RIKEN Big
RIPS, the magnetic characteristics of two types of superconducting quadrupoles, that is, superferric andcos2B (or shell) types have been studied using the2D /3D electromagnetic field calculation codes of "PCOPERA" and "TOSCA/OPERA-3d" .1 ,2)For the 2D field calculation of the quadrupole withhomogeneous quadrupole field region of r < 100 mm,
two superferric type quadrupoles (#1 and #2) shownin Figs. 1 and 2, together with one cos2B type
quadrupole shown in Fig. 3, are compared on the parameters listed in Table 1.
As a result of the field analysis, the following characteristics have become clear for the three quadrupoles.
The superferric # 1 quadrupole magnet can produce
the homogeneous quadrupole field with small multipoles of higher order, but only on the low excitation
region as shown in Fig. 4. Contrarily, the superferric

300
250--. 200§

Air-- 150;>, 100

50

X (IIU11)

Fig. 3. Cross section (1/8 sector) of a cos20 type
quadrupole magnet for 2D field analysis.
Table 1. Major parameters of superconducting quadrupoles (2D calculation).
Type350~--~----~--~~~~--~

300
250
~ 200
;>,

Air

150

400

100

Pole tip diameter(mm)
Warm clear bore(mm)
Current density

superfenic
(#1)
240

superfenic
(#2)
240

cos(2e)

200

200

200

150

100

180

1600

1340

1630

2.40x10 51.34xI0'i

2.93xl0 5

19.9

19.6

20.4

4.0

3.1

3.8

(300)*(Almm 2 )

100
50
400

500

Cross section ofcurrent blocks(mm 2)
Total current/pole(A)

Field gradientFig. 1. Cross section (1/8 sector) of a superferric #1
quadrupole magnet for 2D field analysis.

(Tim)

Maximum field**(T)*) inner diameter of coil

300
250

0.002~--------~------~--. 200

g

0.001

-150
;>,

-+- b6

Air

* b10

~

100

..Q

50

-0.001.•- 0.002b14- .,- b1B
400
X (IIU11)

Fig. 2. Cross section (1/8 sector) of a superferric#2 quadrupole magnet (almost equivalent with Q1 at
MSU) for 2D field analysis.

224

o

50

100 150 200

I (kA)
Fig. 4. Allowed normal multipole coefficients vs. exciting current for the superferric #1 quadrupole magnet
shown in Fig.!.

#2 quadrupole magnet (MSU type) can produce theho~ogeneous quadrupole field only on the high exci-

tation region as shown in Fig. 5. 3 ) Furthermore, thecos2B type quadrupole magnet can produce the homogeneous quadrupole field on the almost entire excitation region as shown in Fig. 6. Comparison between
MSU and cos2B types are made in Table 2.
For the RIKEN Big RIPS, approximately 40- 50 setsof the triplet quadrupoles are to be operated at different exciting currents. As a result, a low-current operation is indispensable, thereby reducing the heat input
through the current leads. Therefore, for the super-

0.003~~--~--------~---'

0.002
0.001

----+- b6

O--~~--~r-~~~'-~~.a -0.001* . b10.. ...* .. ...*.

-0.002-0.003-0.004

o

20 40

.•

b14

-1Ir-

b18

60 80 100120
I (kA)

Fig. 5. Allowed normal multipole coefficients vs. exciting current for the superferric #2 quadrupole magnet
shown in Fig. 2.

o ---IIr--- .. - - - - 4-0.0002-+- b6s:: -0.0004..Q.* b10-0.0006-0.0008o

50 100 150 200 250 300
I

•

b14

-1Ir-

b18

ferric quadrupole at MSU, the major coils were woundby a fine conductor with the diameter of less than
1 mm.
On the other hand, for the cos2B type
quadrupole, the multi-strand cable of the so-called
Rutherford type 2 ) with a large current capacity can
not be adopted. Instead of the Rutherford cable, theflat cable with parallel unconnected strand (so-calledribbon conductor)2) become a candidate for the conductor.
Because the winding by a ribbon conductor seems to
be costly and difficult for the cos2B type quadrupole,
we are planning to try the superferric type quadrupole
first. Now, the triplet set with length of 0.5, 0.8, and
0.5 m of the superferric #2 quadrupole magnets, having a large bore radius for homogeneous quadrupole
field region r < 120 mm, is under study, in orderto improve the field homogeneity. Characteristics ofthe quadrupole coil under study are listed, together
with those of sextupole and octapole coils are listed inTable 3. A cross-sectional view of their coils is shownin Fig. 7.
Table 3. Major parameters of a superconducting quadrupole magnet with the effective length of 0.8 m (2D &3D calculation).

Field
Total current(A) Ipole
Length (m)[straight]
Length (m)[end]Quadrupole14.1 Tim
2.7x105

sextupole
20.8 T/m 2
3.9xI04

octupole

0.7

0.7

0.7

0.1 x 20.1 x 20.1 x 2174 T/m 3
2.9xlO4(kA)

Fig. 6. Allowed normal multi pole coefficients vs. exciting
current for the cos20 type quadrupole magnet shown in
Fig. 3.

Quadrupole coil (4.5 K)
Sextupole coil (4.5 K)
Octupole coil (4.5 K)

Table 2. Comparison between superferric and cos20 types(2D & 3D calculation).
Type
Homogeneity ofgradient field(straight region)
Contribution ofiron
Maximum field
Maximum
current density
Winding andconductor types

Magnetic force
Fabrication costsuperferric (#2)
Ig - gol < 4 %cos28
Ig - gol < 0.5 %

62%

28 %

3.14 T
j=IOO A/mm 23.77 T.i=180Nmm 21) random
winding(MSU)I) ribbon
conductor (CERN)
2) automatic
winding (BNL)
large
large

small
small

Beam pipe (300 K)

Fig. 7. Cross section of a superconducting quadrupole
magnet equipped with the sextupole and octupole coils.

References
1) Vector Fields Limited, Oxford, England.
2) K.-H. Mess, P. Schmiiser, and S. Wolff: Superconducting
Accelerator Magnets (World Scientific, 1996).
3) B. Zhang: Ph. D thesis, MSU (1997).

225

RIKEN Accel. Prog. Rep. 32 (1999)

Symplectification for the Map of Orbital Motion in a Realistic
Siberian Snake Obtained by DA Approach
M. Xiao, E. Forest, * and T. Katayama
The issue of symplectic integration has been addressed by several authors. 1- 3 ) Grossly speaking, symplectic integrators can be divided into the explicit andimplicit types. Most accelerator physics codes, of the"kick-code" variety, are explicit integrators. These
codes are fast and conceptually simple because a variety of effects can be added to them in a more or lessself-consistent way. Unfortunately, it seems very hardto produce explicit symplectic integrators for a nonideal magnetic field, the complexity is compounded by
the absence of an analytical representation for the magnetic field.
Therefore, we have opted here to keep using an ordinary integrator, from which we extract a map. This
has a small advantage: because the integrator is not
symplectic, any violation of the symplectic condition
will be a reflection of the integration accuracy or of the
non-Maxwellian aspects of the fields. In other words
it gives us an idea of the absolute error before any
symplectic "fudging" algorithm masks it.
The DA(Differential Algebra) approach pioneeredby Berz in beam physics permits the calculation of atruncated Taylor map of an arbitrary element to any
order, and the Taylor coefficients of the resulting truncated map will be accurate to machine precision. It
is a technique to propagate the derivatives of a function f(Xi) systematically through mathematical transformations on f by simply applying the familiar sum,product and chain rules of differentiation. The derivatives of any complicated function, which may be obtained by successive mapping, can be calculated by extending any function f to a vector f which contains thevalue of the function as the first element and the valuesof the derivatives with respect to all the variables up
to the desired order in the subsequent elements. These
vectors are called "DA-vectors,,4,5)of
02f{f,··,-;;-··,··o 0 .. , ... }UXi

Xivariables is replaced by a vector operation. Then, atruncated Taylor map

could be obtained.
The LBNL version of the DA package written by
Berz was introduced, and Program SSSTRA was modified into a DA-version, named DA-SSSTRA. Field distribution of the helical magnet in Siberian Snake wasgiven numerically. In order to make use of DA, themagnetic field was reconstructed again to the second
order as follows,

obw(x,y,s)ox.X2
obw(x, y, s)
1 0 bw(x, y, s)2+oy. Y + "2 .
Ox2.X

B w( X, y, s ) = bw (X, y, s ) ++02bw(x,y,s)
1 02bw(x,y,s)2
8x8y. xy + 2 .
oy2. Y + ...
w = x,y, or s

Where bw(x, y , s) as well as its first and second derivatives are expressed by spline interpolation functions 6 )fitted from the numerical field data. Since the spline
function is smooth in the first derivatives and continuous in the second derivatives, the truncated Taylor
map to the second order can be obtained around any
ray started from the entrance of the snake.
The field strengths of each helical magnet for
Siberian Snake Type I (Spin axis is 45° with respect
to s-direction) were optimized first in order to makethe spin precession turn 180 0 at the storage mode
(E = 250 GeV). Then, the four-dimensional map to
the second order around any ray can be extracted automatically. Linear matrices for the motion at injection mode (E = 25 Ge V) and at storage mode aroundthe center ray are given as follows ,Xj-0.0004-0.0038-0.0002

0.9971

12.2738
0.99740.02410.00650.00110.00010.9336-0.0107-0.0255]

0.9999-0.0000
MTs = [ -0.0000-0.0000

12.2799
0.99990.0001-0.0001

0.0000-0.0000
0.9995-0.0001-0.0003][{f, ··fXi .. , . .fxi X)"" ... }.
For map-tracking, all phase-space coordinates Zi become the DA vectors Zi. The first element of Zi contains the current value of the coordinates Zi, and thesubsequent elements contain the derivatives with respect to the initial values of Zi . The vectors Zi are initialized by setting the first element to the initial valueof Zi, the element which contains the first derivativewith respect to the ith initial coordinate is set to beunity(I), and all the other elements are zero. Eachmathematical operation which involves phase-space
High Energy Accelerator Research Organization (KEK)

226

MT/ =

-0.0050
11.9255
0.9347-0.0001
12.27770.9995A 2n x 2n matrix, M, is said to be symplectic if

MT ·J·M = J ,where MT is the transpose of M, and J is the matrix,

a Poisson bracket approximating this general vector
field. We then compute
Here each entry in J is an n x n matrix, I denotes then x n identity matrix, and all the other entries are
zero. It follows that a symplectic matrix has a unit
determinant.
Checking of the symplecticity for maps of the snake
was made, and the results showed that although a deviation of the determinant of M T [ and MTs from 1 isas small as 8.6597396 x 10- 15 and 2.8199665 x 10- 14 respectively, it does not satisfy the symplectic conditions
completely: the maximun error among the matrix elements is 9.1694 x 10- 2 for M T [ and -1.2853 x 10- 5 forMTs' The Maxwellian property of the magnetic fieldaround the central ray was checked and it was foundthat the maximum error is around 10- 2 , the same order as the symplectic property of the orbital matrix.
The Dragt-Finn factorization states that a map near
the identity can be expressed as follows, 1)

MK = exp(F . \1)1 d,
where I d=identity map. The Poisson bracket operator, [j, g], is a special case of the general vector field
operator: I: §= [j,gj = \1IT. J. \1§= -J\1I·\1§,~

F

where § is an arbitary vector function of phase space.
Then,
x

.....

,

1= 0 J. F· dx.
/.

If F is symplectic, then this computation involves anintegral of a curl free function. Thus, the function I
is unique. If F is slightly non-symplectic, then thefunction I is one of possible symplectifications of thevector field F, and it will depend on the path of theintegration.
We know that the map M (including second order)
from the entrance to exit of the snake is nearly the map
for a drift of the length equal the full snake. Therefore,
one needs to construct a new map M K given by

MK = D_1(L)

2' M . D_1( L)

2'

where D(L/2) is a drift of half length of the full snake.
So the linear part of the M K is a matrix near the identity.
In the program DA-SSSTRA, a possible symplectic
matrix Mx:. for MK was computed by an iterative process as follows. First, we compute the vector F in sucha way that MK = exp(F .\1) I d. Later, we will findvectorm = exp( -Fj . \1) . MK - 1d
as a correction of F, and check whether vectorm isclose enough to zero. If not, then we set

Fj +1 ¢= Fj + vectorm
and repeat the iteration.
Notice that this computation does not separate themap to be symplectified into the first and second orders, so it can be used for the symplectification of arbitrary order.
Once, : I : is obtained from F, the resulting symplectified map is

M = D(L/2) . MK . D(L/2)= D(L/2) . exp(: f :)ld· D(L/2) .
The maps for the Siberian Snake generated by numerical magnetic field including second order were
symplectified, and the following are the symplectified
linear matrices M T [ and MTs obtained by DA

M T[ =-0.0037 -0.0294][ -0.0004
0.9971 12.2740
0.9975 -0.0001 -0.0016
0.0008-0.0001

0.02730.00290.9336-0.0107

11.92560.93480.9999-O.OOOQ
MTs = [
0.0000-0.0000

12.2799
0.99990.0002-0.0001-0.0000-0.0000
0.9995-0.0001-0.0004]-0.000212.27770.9995The symplectification results show that there is alittle adjustment for the linear map of the snake calculated by DA to be symplectic, but for the second ordermap, the elements corresponding to the cross terms
such as Xo . PX o change significantly.
Further work is being done to put the symplectified
map into the full lattice of RHIC for spin tracking.
The accuracy will have to be gauged in an actual run.

References
1) A. J. Dragt: AlP Conf. Proc. 87, 147 (1982).
2) H. Yoshida: in Celestial Mechanics and Dynamical Astronomy (1993) p. 56.
3) E. Forest et al.: KEK Report 92-14, Sept. (1992).
4) M. Berz: in Particle Accelerators, Vol. 24 (1989) p. 109.
5) F. Willeke: Proc. CAS (CERN Accelerator School)
Fifth Advanced Accelerator Physics Course, CERN 9506, Greece, 1993 (1995).
6) M. Xiao et al.: Spin note AGS/RHlC/SN No. 078, Sept .
10 (1998).

227

v.

RADIATION MONITORINGRIKEN Accel. Prog. Rep. 32 (1999)

Routine Works for Radiation Safety in
the Ring Cyclotron Facility
S. Fujita, S. Nakajima, S. Ito, T. Arakawa,* A. Fujiwara,* M. Kase, and Y. Uwamino
The radiation safety control system has worked
steadily during this year (1998) so as to enable us to
execute the radiation monitoring service continuously
and automatically.
From the accumulated data of leakage neutrons, theradiation level in the controlled area was found muchless than the recommended dose limit (0.3 mSv /week).
Leakage of neither f rays nor neutrons was detectedwith environmental monitors installed outside thebuilding during this reporting period. Then, we haveevaluated the radiation level at the boundary of the accelerator facility. The leakages was recorded with themonitor installed in the ground-floor computer room
which is just above a bending magnet that guides thebeams from the Ring Cyclotron vault to the distribution corridor. The radiation level (4.5 /-lSV /year)
was much less than the recommended dose limit(1 mSv/year).
Two hand-foot-cloth (HFC) monitors with (3( f) detector had been used at the entrance of the controlledarea before the last winter-98. When one of the HFC
monitors was out of order, we could use only one HFC
monitor. So many people could not get out smoothly
during that period. To improve the situation, we haveinstalled a new HFC monitor which can detect a-rays
as well as (3(,) February-1998. Usually, two HFC monitors are connected to the computer system and one
HFC is reserved. Using a newly made switching box,
we can easily swap the connection. Therefore, we areable to use two HFC monitors always, even if a trouble occurred to one of the HFC monitors. In addition,

the system is able to check a rays for enhanced safety.
Figure 1 is the photograph showing the new HFC monitor and the switching box at the entrance into thecontrolled area.
Around February-1999, we are going to replace
the computer system by Radiation Safety Control
System l ) with new one.

Fig. 1. Photograph of the new hand-foot-cloth monitor
on the right hand side which is able to detect both (3(r)
and Q: rays, and of the new switching box at the foot of
the old hand-foot-cloth monitor seen in the left.

References
1) 1. Sakamoto, S. Fujita, T. Wada, and H. Takebe:
RIKEN Accel. Prog. Rep. 20, 206 (1986).

Faculty of Science, Science University of Tokyo

229

RIKEN Accel. Prog. Rep. 32 (1999)

Dose Rates Due to Residual Radioactivity
in the Ring Cyclotron Facility
S. Fujita, T. Arakawa, * A. Fujiwara, * S. Nakajima, S. Ito,
M. Kase, and Y. Uwamino
Residual radioactivities in the Ring Cyclotron Facility were measured on the surface at various spots using
ionization-chamber survey meters. The measurements
were performed during the routine overhaul period aswell as after almost every beam time. In the following,
we report the significant dose rates observed throughmeasurements.
A client experiment was carried out with an 18 0
beam of 100 MeV/nucleon in the E6 experimental
vault from July 22 to July 31,1998, as the last beamtime of the spring term. As the last beam of the term, aproton beam was accelerated up to the energy 14 MeV
in the AVF cyclotron vault on Aug. 3. The routine
overhaul started just after that date. The dose rates
in the Ring cyclotron and in the AVF cyclotron were
measured from Aug. 21 till 31 in this period. The results are shown in Figs. 1 and 2.
In addition to the above routine measurement, dose
rates inside the AVF cyclotron were measured onJune 11 when its acceleration chamber was opened due
to a trouble of insulation of the deflector in vacuum.
The result is also shown in Fig. 2.

Deflector~~====== Pro b e

DOSE UNIT

Beam

~Sv/h

Fig. 2. Dose rates measured inside the injector AVF cyclotron. They are given in units of j.LSV Ih, and asterisk( *) indicates an extra measurement made on June 11.

Table 1. Summary of the dose rates measured along thebeam lines with ionization-chamber survey meters. The
detection points a-w indicate the measured spots shownin Fig. 3.
Detection Measured
point dose rate

Date(~v/h)

a
b
c
d

e
f
g
h

j
k
m
n

Fig. 1. Measured spots around the RIKEN Ring
Cyclotron: EDC, the electrostatic deflection channel;
MDC1, the magnetic deflection channel 1; MDC2, themagnetic deflection channel 2; MDP1, the main differential probe 1; MDP2, the main differential probe 2;
and MDP3, the main differential probe 3. The numbers are dose rates in units of J.LSV Ih.

0

P
q
r

s
t
u
V

w

Faculty of Science, Science University of Tokyo

230

70
100
150
230
1200
1000
100
180
150
580
70
230
950
220
4000
400
80
1500
300
3400
1500
450
700

lun 11, '98
lui 17, '98
lun II, '98
Mar 13, '98
lui 2, '98
Apr 2, '98
lui 2, '98
Apr 30,'98
Apr 2, '98
lun 11, '98
Dec 8, '97
Mar 13, '98
Aug 3, '98
Feb 19, '98
Apr 6, '98
lun 11, '98
Dec 8, '97
May 27,'98
Dec 8, '97
Apr 24,'98
Apr 24,'98
Oct 16,'97
lun 29,'98

The ex~riment ,ereceded
particle energy intensity period(MeV/n) (enA) (days)
d
135
210
4
0-18
100
1200
6
d
135
210
4
Ca-40
100
600
6
C-13
115
1200
4
0-18
100
3000
13
C-13
115
1200
4
135
N-14
1560
0-18
100
3000
13
d
135
210
4
Co-59
80
300
5
Ca-4O
100
600
6
0-18
100
3690
9
8-11
70
1560
4
0-18
100
3000
13
d
135
210
4
Co-59
80
300
5
C-12
135
580
5
Co-59
80
300
5
N-14
135
2000
4
N-14
135
2000
4
d
70
310
3
d
135
940
6

Fig. 3. Layout of the RIKEN Ring Cyclotron Facility as of 1998. Measured spots ofresidual radio-activities along the beam lines are shown by bullets a-w.

In the period from Oct. 1, 1997 till Sept. 30, 1998,
dose rates were measured along the beam lines. The
spots a-w marked by bullets in Fig. 3 are the places
where the dose rates exceeded 50 J-lSV Ih. Table 1 summarizes the observed dose rates with the dates whenthe measurements were performed. The maximum

dose rate was found to be 4 mSv Ih (4000 J-lSv Ih) at
the target chamber, denoted by the spot 0 in Fig. 3.
Whenever we observed a high dose rate in some place,
we roped the area and posted a sign warning that it
was dangerous to stay long in that place.

231

-

VI. LIST OF PUBLICATIONS
1.

Accelerator
physics

development

andaccelerator

A. Goto, Y. Yano, and T. Katayama: "RIKEN RI
Beam Factory project", Proc. 6th China-Japan Joint
Symp. on Accelerators for Nuclear Science and Their
Applications, Chengdu, China, 1996-10, edited by S.
Guanqing and L. Zhengda, pp. 28- 31 (1996).
A. Goto, Y. Miyazawa, M. Kase, O. Kamigaito, T.
Nakagawa, M. Hemmi , T. Chiba, N. Inabe, S.
Kohara, T. Kageyama, Y. Batygin, E. Ikezawa,
and Y. Yano: "New pre-injector system of the RILAC for the RIKEN RI Beam Factory project",
Proc. 6th China-Japan Joint Symp. on Accelerators for Nuclear Science and Their Applications,Chengdu, China, 1996-10, edited by S. Guanqing and
L. Zhengda, pp. 161-165 (1996).
T. Nakagawa, M. Kidera, Y. Miyazawa, M. Hemmi,
T. Chiba, N. Inabe, M. Kase, T. Kageyama, O.
Kamigaito, A. Goto, and Y. Yano: "Production ofmulticharged Os ion beams from organic metal compounds using a RIKEN 18 GHz electron cyclotron
resonance ion source", Jpn. J. Appl. Phys. 36,
7375-7376 (1997).
T. Nakagawa, J. Arje, Y. Miyazawa, M. Hemmi ,T. Chiba, N. Inabe, M. Kase, T. Kageyama, O.
Kamigaito, A. Goto, M. G. Niimura, and Y. Yano:"Production of highly charged metal ion beams
from organic metal compounds at RIKEN 18 GHzECRIS" , Nucl. Instrum. Methods Phys. Res. A
396, 9-12 (1997).
T. Katayama, Y. Batygin, N. Inabe, K. Ohtomo, T.
Ohkawa, M. Takanaka, M. Wakasugi, S. Watanabe,
Y. Yano, K. Yoshida, J. Xia, Y. Rao, and Y. Yuan:"The MUSES project at the RIKEN RI Beam Factory", Nucl. Phys. A 626, 545c- 560c (1997).
M. Niimura, A. Goto, and Y. Yano: "Structure of
the ECRIS-nucleus: Evidence of a high-energy electron layer", Proc. 13th Int. Workshop on ECR Ion
Sources , College Station, USA, 1997-02, edited by D.
P. May and J. E . Ramirez, pp. 52- 66 (1997).
A. Goto, Y. Yano, and T. Katayama: "RIKEN RIBeam Factory project", J. Phys. G: Nucl. P art. Phys.
24, 1341- 1345 (1998).
J .-W. Kim, A. Goto, T. Mitsumoto, T . Kubo, H.
Okuno, T. Kawaguchi, T. Tominaka, S. Fujishima,
K. Ikegami, N. Sakamoto, S. Yokouchi, T. Morikawa,and Y. Yano: "Trim coil system for the RIKEN Superconducting Ring Cyclotron", Proc. 1997 Particle
Accelerator Conf. (PAC '97), Vancouver, Canada,
1997-05, edited by M. Craddock, pp. 3422-3424(1998).
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T. Nakagawa, J. Arje, Y. Miyazawa, M. Hemmi, T.
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Nuclear physics and nuclear instrumentation

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K. H. Kim and T. Otsuka: "Multiphonon structure ina ,-unstable fermionic model", Phys. Rev. C 52,
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Y. H. Zhang, Y. Gono, A. Ferragut, K. Morita,
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Komatsubara, J. Lu, S. J. Chae, C.-J. Kim, and B.-J.
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M. Shibata, A. Odahara, S. Mitarai, Y. Gono, M.
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N. Sakamoto, H. Okamura, T. Uesaka, S. Ishida, H.
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A. Yoshida, C. Signorini, T. Fukuda, Y. Watanabe, N.
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T. Mizusaki, M. Honma, and T. Otsuka: "Quantum
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H. Sakurai, N. Aoi, A. Goto, M. Hirai, N. Inabe, M.
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Y. Watanabe, and A. Yoshida: "Production andidentification of new neutron-rich nuclei, 31 Ne and37Mg, in the reaction 80A MeV 50Ti + 181Ta", Phys.
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T. Akiba, E802 Collaboration, K. Kurita, and H.
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K. H. Kim, T. Otsuka, A. Gelberg, P. von Brentano,and P. van Isacker: "Supersymmetric multiphonon
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T. Otsuka: "Microscopic basis of the interacting Boson
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N. Yoshinaga, T. Mizusaki, A. Arima, and Y. D. Devi:"Microscopic foundations of the interacting Boson
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T. Mizusaki and T. Otsuka: "Microscopic calculations
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M. Honma and T. Otsuka: "Superdeformation in
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Y. Miyake, K. Shimomura, A. Milles, P, and K.
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A. A. Gusev, T. Kohno, W. Spjeldvik, 1. M. Martin,
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T. Takashima, T. Doke, T. Hayashi, J. Kikuchi, M.
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C. Kato, K. Munakata, T. Kohno, K. Kondoh , H.
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Y. Mochizuki, K. Oyamatsu, and T. Izuyama: "Exotic
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Y. H. Zhang, Y. Gono, T. Morikawa, E. Ideguchi,
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K. Morita, A. Yoshida, H. Kumagai, T. Murakami,
M. Oshima, H. Iimura, M. Shibata, S. Hamada, H.
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Z. Ren, T . Otsuka, H. Sakurai, and M. Ishihara:"Skyrme-Hartree-Fock approach to proton halo in
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H. Miura, T. Tachibana, K. Sumiyoshi, Y. Mochizuki,
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Y. Ogawa and 1. Tanihata: "Momentum distributionof 7Be from (8B, 7Be) reaction within the Glaubermodel", Nucl. Phys. A 616, 239c-246c (1997).
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A. A. Korsheninnikov, E. Y. Nikolskii, C. A. Bertulani,
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J. K. Ahn , E224 Collaboration, Y. Goto, and N. Saito:"Scalar and vector meson production and two-stepprocesses in the (K-, K+) reaction on 12C", Nucl.
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K . Nagamine: "Probing inner-structure of volcano
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T. Kikuchi , T. Motobayashi, N. Iwasa, Y. Ando, M.
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M. Petrascu, I. Tanihata, T. Kobayashi, A. Isbasescu ,H. Petrascu, A. A. Korsheninnikov, E. Nikolski, S.
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H. Nakada and T. Otsuka: "Microscopic analysis ofquadrupole collective motion in Cr-Fe nuclei: II.
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Lefebvre, 1. Linck, W. Mittig, T. Motobayashi, F.
de Oliveira Santos, P. Roussel-Chomaz, C. Stephan,and J. P. Thibaud: "Fragment angular correlation in
the breakup of 16 0 ions at 95 MeV/A" , N ucl. Phys.
A 633, 373- 387 (1998).
K. Oyamatsu, 1. Tanihata, Y. Sugahara, K. Sumiyoshi,
and H. Toki: "Can the equation of state of asymmetric nuclear matter be studied using unstable nuclei?" ,Nucl. Phys. A 634, 3-14 (1998).
N. Dinh Dang and A. Arima: "Temperature dependence of quantal and thermal dampings of the hot
giant dipole resonance", Nucl. Phys. A 636, 427451 (1998).
D. L. Adams, Fnal E704 Collaboration, Y. Goto, and
N. Saito: "Measurement of single spin asymmetryin 1]-meson productions in PrP and PrP interactions
in beam fragmentation region at 200-GeV Ie", Nucl.
Phys. B 510, 3- 11 (1998).
E. Kim, T. Nakamura, A. Konno, Y. Uwamino, N.
Nakanishi, M. Imamura, N. Nakao, S. Shibata, and
S. Tanaka: "Measurements of newtron spallation
cross sections of 12C and 209Bi in the 20- to 150MeV energy range", Nucl. Sci. Eng. 129, 209- 223(1998).
Y. D. Devi, A. Arima, and N. Yoshinaga: "Nuclear
shell model and interacting Boson Fermion approximation", Phys. Lett. B 418 , 13- 19 (1998).
J . Meng, 1. Tanihata, and S. Yamaji: "The proton andneutron distributions in Na isotopes: The development of halo and shell structure", Phys. Lett. B
419, 1-6 (1998).
J. A. Tostevin, S. Rugmai, R. C. Johnson, H.
Okamura, S. Ishida, N. Sakamoto, H. Otsu, T.
Uesaka, T. Wakasa, H. Sakai, T. Niizeki, H.
Toyokawa, Y. Tajima, H. Ohnuma, M. Yosoi, K.
Hatanaka, and T. Ichihara: "Coulomb breakup oflight composite nuclei", Phys. Lett. B 424, 219-225(1998).
M. Sugita, K . Uchiyama, and K. Furuno: "Quadrupole
deformation of barium isotopes" , Phys. Lett. B 440,
239-245 (1998).
N. Pietralla, T. Mizusaki, P. von Brentano, R . V.
Jolos, T. Otsuka, and V. Werner: "2i andstatesin collectiv nuclei multiple Q-phonon excitations",
Phys. Rev. C 57, 150-158 (1998).
M. Schafer, W.-D . Schmidt-Ott, T. Dorfier, T. Hild,
T. Pfeiffer, R . Collatz, H. Geissel, M. Hellstrom, Z.
Hu, H. Irnich, N. Iwasa, M. Pfiitzner, E. Roeckl, M.
Shibata, K. Asahi, H. Izumi, H. Ogawa, H. Sato, H.
Ueno, and H. Okuno: "Polarization in fragmentation
and 9 factor of 35K", Phys. Rev. C 57, 2205- 2214
(1998).
N. Dinh Dang and F. Sakata: "Relation between
damping of the hot giant dipole resonance andthe complex admittance of an irreversible process",
Phys. Rev. C 57, 3032-3048 (1998).
J. Meng, K . Sugawara-Tanabe, S. Yamaji, P. Ring,
and A. Arima: "Pseudospin symmetry in relativistic
mean field theory", Phys. Rev. C 58, R628-R631(1998).
H. Okamura, S. Ishida, N. Sakamoto, H. Otsu,
T. Uesaka, T. Wakasa, H. Sakai, T. Niizeki, H.
Toyokawa, Y . Tajima, H. Ohnuma, M. Yosoi, K.
Hatanaka, and T. Ichihara: "Mechanism of theforward-angle (d, pn) reaction at intermediate energies", Phys. Rev. C 58, 2180-2191 (1998).
T. Ito, R. S. Hayano, S. N. Nakamura, T. P. Terada,
M. Iwasaki, D. R. Gill, L. Lee, A. Olin, M. Salomon,
S. Yen, K. Bartlett, G. A. Beer, G. Mason, G.
Trayling, H. Outa, T. Taniguchi, Y. Yamashita, and
R. Seki: "Observation of kaonic hydrogen atom X
rays", Phys. Rev. C 58, 2366-2382 (1998).
M. R. Ahmady, E. Kou , and A. Sugimoto: "Intermediate psuedoscalar resonance contributions to
B~Xs'Y'Y", Phys. Rev. D 57, 1997- 2000 (1998).
R. L. Jaffe, X. Jin, and J. Tang: "Interference fragmentation functions and valence quark spin distributionsin the nucleon", Phys. Rev. D 57,5920-5922 (1998).
K. Bora and R. L. Jaffe: "Double-scattering contribution to b1(x, Q2) in the deuteron", Phys. Rev. D
57, 6906-6911 (1998).
N. Dinh Dang and A. Arima: "Quantal and thermal
dampings of giant dipole resonance in 90Zr, 120Sn,
and 208Pb'', Phys. Rev. Lett. 80,4145- 4148 (1998).
T. Kohno, H. Miyasaka, H. Kato, C. Kato, T. Goka,
and H. Matsumoto: "Heavy ion radiation in spaceobserved by Japanese satellite" , Proc. 3rd Int. Workshop on Radiation Effects on Semiconductor Devices
for Space Application, Takasaki, pp. 90-95 (1998).
T. Goka, H. Matsumoto, S. Takagi, T. Kohno, andF. Makino: "Empirical radiation belt models basedon the Japanese satellites measurements", Proc. 3rd
Int. Workshop on Radiation Effects on Semiconductor Devices for Space Application, Takasaki, 1998-10,

2t

237

pp. 96- 101 (1998).
1. M. Martin, A. A. Gusev, T. Kohno, G. 1. Pugacheva,
and W. Spjeldvik: "Space distribution of energetic
He ion flux in magnetosphere: Ohzora observations
during 1984-1986", Proc. 5th Congo Int. Brazilian
Geophysical Society, Sao Paulo; 1997-10, edited by
Y. R. Marangoni et al., pp. 1085- 1088 (1998).
A. A. Gusev, 1. M. Martin, G. 1. Pugacheva, A. Jr.
Turtelli, T. Kohno, and W. Spjeldvik: "The secondary proton radiation belt: Origin and dynamics" ,Proc. 5th Congo Int. Brazilian Geophysical Society,
Sao Paulo, 1997-10, edited by Y. R. Marangoni etal., pp. 1093-1097 (1998).
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. Kudoh, N. Takeda, and G. H. Eaton:"Muon catalyzed fusion (J.lCF) experiment at the
RIKEN-RAL Muon Facility (I): X-ray and neutron
measurement of J.l to a sticking probability", Proc.
Int. Symp. on Laser Application to Muon Science,
Tsukuba, 1998-03, edited by Y. Miyake, K. Shimomura, and K. Nagamine, High Energy Accelerator
Research Organization, pp. 126- 130 (1998).
K . Ishida and K. Nagamine: "Simulation of solenoidal
capture of high intensity muon beam at RIKEN /RAL and KEK-MSL", Proc. Int. Workshop on JHF
Science (JHF98), Tsukuba, 1998-03, edited by J.
Chiba et al., High Energy Accelerator Research Organization, Tsukuba, pp. 12- 15 (1998).
J. Kodaira, T. Nasuno, H. Tochimura, K. Tanaka, andY. Yasui: "Renormalization of gauge-invariant operators for the structure function 92 (x, Q2)", Prog.
Theor. Phys. 99, 315-320 (1998).
E. C. Adelberger, S. M. Austin, J. N. Bahcall, A. B.
Balantekin, G. Bogaert, L. S. Brown, L. Buchmann,
F. E. Cecil, A. E. Champagne, L. de Braeckeleer,
C. A. Duba, S. R. Elliott, S. J. Freedman, M. Gai,
G . Goldring, C. R. Gould, A. Gruzinov, W. C.
Haxton, K. M. Heeger, E. Henley, C. W. Johnson,
M. Kamionkowski, R. W. Kavanagh, S. E. Koonin,
K. Kubodera, K. Langanke, T. Motobayashi, V.
Pandharipande, P. Parker, R. G. H. Robertson, C.
Rolfs, R. F. Sawyer, N. Shaviv, T. D. Shoppa, K. A.
Snover, E. Swanson, R. E. Tribble, S. Turck-Chieze,
and J. F. Wilkerson: "Solar fusion cross sections",
Rev. Mod. Phys. 70, 1265- 1292 (1998).

3.

Atomic and solid-state physics

E. Torikai, K. Nagamine, K. Nishiyama, E. Hirose,
Y. Ikedo, T. Hashimoto, P. Birrer , T. Tanaka, H.
Kojima, S. Srinivas, T. P. Das, S. Maekawa, K.
Yamada, S. Hosoya, and Y. Endoh: "Probing interaction of paramagnetic electron with conduction
electrons in high Tc superconductor LaSrCuO by(J.l - O) spin relaxation", Hyperfine Interact. 105,
175- 179 (1997).
238

R. M. Macrae, R. Kadono, F. L. Pratt, K. Tanigaki,
K. Nishiyama, and K. Nagamine: "Longitudinal field
repolarization studies of reorientational dynamics inthe fullerences C 60 and C 70 ", Hyperfine Interact.
106, 175- 180 (1997).
A. Matsushita and K. Nagamine: "Muonium desorption to vacuum from hot iridium surface", Hyperfine
Interact. 106, 283- 289 (1997).
T. Azuma, T. Ito, K. Komaki, T. Tonuma, M. Sano,
A. Kitagawa, E. Takada, and H. Tawara: "Relativistic heavy collisions studies at HIMAC: X-rays fromradiative electron capture into continuum and secondary electrons from binary encounter collisions",
Nucl. Instrum. Methods Phys. Res. B 132, 246-249(1997) .
F.1. Pratt, S. J. Blundell, W. Hayes, K. Nagamine, K.
Ishida, and A. P. Monkman: "Anisotropic polaron
motion in polyaniline studied by muon spin relaxation", Phys. Rev. Lett. 79, 2855- 2858 (1997).
S. Makino, T. Matsuo, M. Mizuno, M. Sano, T.
Kohno, T. Tonuma, H. Tawara, A. Kitagawa, andT. Murakami: "Net-ionization cross sections of raregases by fully-stripped heavy ion impact" , Phys. Scr.
T 73, 238-239 (1997).
T. Azuma, T. Ito, K. Komaki, H. Tawara, T. Matsuo,
T. Tonuma, K. Shima, A. Kitagawa, E. Takada, T.
Murakami, and A. Warczak: "RECC and REC measurements for heavy ion impact on foil targets at relativistic energies", Phys. Scr. T 73, 250-251 (1997).
E. Yagi: "State of hydrogen in Nb-based Nb-Mo alloys
as observed by a channelling method utilizing a nuclear reaction lH(llB, a)aa", RIKEN Rev., No. 16,
pp. 3-4 (1997).
K. Tanaka, E. Yagi, N. Masahashi, Y. Mizuhara, K.
Tatsumi, and T. Takahashi: "Lattice location of B
atoms in an intermetallic compound Nio.75Alo.l5Ti o.lo as observed by a channelling method", RIKEN
Rev., No. 16, pp. 5- 6 (1997).
T . Minamisono, K. Matsuta, M. Fukuda, M. Tanigaki,
Y. Nojiri, H. Akai , M. Mihara, T. Yamaguchi, M.
Sasaki, T. Miyake, T. Onishi, K. Minamisono, K.
Sato, T. Ohtsubo, S. Fukuda, K. Yoshida, A. Ozawa,
S. Momota, and 1. Tanihata: ",B-NMR detections ofshort-lived ,B-emitters 13 0 and 23Mg implanted in Pt
for the studies on anomalous Knight shifts" , RIKEN
Rev. , No. 16, pp. 7-8 (1997).
Y. Ohkubo, Y. Kobayashi, K. Harasawa, S. Ambe, T.
Okada, K. Asai, S. Shibata, and F. Ambe: "TDPAC and emission Mossbauer studies on 99Ru in
YB2CU306.8 and YBa2Cu306", RIKEN Rev., No.
16, pp. 11-12 (1997).
T. Okada, Y. Noro, Y. Kobayashi, J. Nakamura, H.
Kitazawa, and F. Ambe: "Giant hyperfine magnetic
field at 61 Ni in spinel-type chromites", RIKEN Rev.,
No. 16, pp. 23-24 (1997).
J. Nakamura, Y. Noro, T. Okada, Y. Kobayashi, H.
Kitazawa, and F. Ambe: "Hyperfine interaction of
61 Ni in CU1-xNixCr204: The effect of unquenchedorbital angular _momentum", RIKEN Rev., No. 16,
pp. 25-26 (1997).
T. Nishimura: "Vibrationally elastic scattering of
positrons from CH 4 molecules", At. Collision Res.
Jpn: Prog. Rep. 24, 7- 9 (1998).
Y. Sakura:i: "High energy inelastic scattering beamline
for electron momentum density study", J. J pn Soc.
Synchrotron Rad. Res. 11, 114- 121 (1998).
T. Kambara, M. Kimura, Y. Awaya, T. M. Kojima, V.
Mergel, Y. Nakai, and H. Schmidt-Backing: "Stateselective differential cross sections of electron capturein 10 MeV Ar 8 + -He collisions", J. Phys. B: At. Mol.
Opt. Phys. 31, L909-L914 (1998).
T. Nishimura: "Theoretical study of electron scattering from CH 2 F 2 molecules", J. Phys. B: At. Mol.
Opt. Phys. 31,3471- 3478 (1998).
E. Yagi and S. Koike: "Change of site occupancy ofhydrogen in Nb on alloying with undersized Mo", J.
Phys. Soc. Jpn. 67, 340-344 (1998).
E. Yagi: "Studies on hydrogen in metals and alloys
by the nuclear reaction channelling method", Met.
Technol. 68, 49-58 (1998).
N. Ishikawa, Y. Chimi, A. Iwase, H. Maeta, K . Tsuru,
O. Michikami, T. Kambara, T. Mitamura, Y. Awaya,
and M. Terasawa: "Electronic excitation effects in
ion-irradiated high- Tc superconductors", Nucl. Instrum. Methods Phys. Res. B 135, 184-189 (1998).
Y. Sugaya, D. Ashery, J. Chiba, H. Ito, K. Kimura,
Y. T. Kiselev, S. Koda, K. Miyano, T. Murakami,
J. Murata, T. Nagae, Y. Nakai, M. Nomachi, M.
Numajiri, H Ochiishi, S. Sawada, M Sekimoto, T.
Shibata, T. Suzuki, K. H. Tanaka, M. K. Vlasov,Y. Yamanoi, K. Yasuda, and Y. Yoshimura: "Subthreshold antiproton production in pA, dA and aAreactions", Nucl. Phys. A 634, 115-140 (1998).
I. Shimamura: "Antiprotonic helium" , Photonic, Electronic and Atomic Collisions, Vienna, Austria, 199707, edited by F. Aumayr and H. Winter, World Scientific, pp. 631-638 (1998).
D. Bakalov, K. Bakalova, V. I. Korobov, H. J.
Monkhorst, and I. Shimamura: "Fine and quadrupole structure of the weakly bound systems(dtj.t)l1 dee and (ddj.t) 11 dee", Phys. Rev. A 57, 33703375 (1998).
A. Igarashi, I. Shimamura, and N. Toshima: "Hyperspherical close-coupling study of hyperfine transitions in low-energy p + pj.t and e± + Ps scattering" ,Phys. Rev. A 58, 1166-1173 (1998).
V. Mergel, M. AchIer, R. Dorner, Kh. Khayyat,
T. Kambara, Y. Awaya, V. Zoran, B. Nystrom,
L. Spielberger, J. H. McGuire, J. Feagin, J.
Berakdar, Y. Azuma, and H. Schmidt-Backing: "Helicity dependence of the photon-induced three-body
Coulomb fragmentation of helium investigated bycold target recoil ion momentum spectroscopy",
Phys. Rev. Lett. 80, 5301- 5304 (1998).
M. Terasawa, N. Takezawa, K. Fukushima, T.
Mitamura, X. J. Fan, H. Tsubakino, T. Kohara,

K. Ueda, Y. Awaya, T. Kambara, M. Matsuda,
and G. Tatar a: "Flux pinning and flux creep
in La2-xSrxCu04 with splayed columnar defects",
Physica C 296, 57-64 (1998).
E. Yagi: "Studies of impurities in metals by a channelling method utilizing a nuclear reaction", Proc.
Int. Workshop on JHF Science (JHF98), Tsukuba,
1998-03, edited by J. Chiba et al., High Energy Accelerator Research Organization, Tsukuba, pp. 380383 (1998).
Y. Nakai, A. Itoh, T. Kambara, Y. Bitoh, Y. Awaya,
and Y. Yamazaki: "Fragmentation of C 60 in close
collision with fast carbon ions", RIKEN Rev., No.
17, pp. 55-56 (1998).
H. Tsuchida, A. Itoh, Y. Nakai, K. Miyabe, M. Imai,and N. Imanishi: "Effects of collective excitation
on ionization and fragmentation of C 60 by high energy H+ impacts", RIKEN Rev., No. 17, pp. 57-58(1998) .
T. Nishimura: "Vibrationally elastic scattering of
positrons from CH 4 molecules", RIKEN Rev., No.
19, pp. 65-66 (1998).
E. Yagi: "Ion beam analysis with accelerators" , Vac.
J., No. 56, pp. 20-21 (1998).
4.

Radiochemistry, radiation chemistry, and radiation biology

I. Narumi,

K. Cherdchu, S. Kitayama, and H.
Watanabe: "The Deinococcus radiodurans uvrA
gene:
Identification of mutation sites in two
mitomycin-sensitive strains and the first discovery
of insertion sequence element from deinobacteria",
Gene 198, 115- 126 (1997).
T. Ban-nai, Y. Muramatsu, S. Yoshida, S. Uchida, S.
Shibata, S. Ambe, F. Ambe, and A. Suzuki: "Multitracer studies on the accumulation of radionuclides
in mushrooms", J. Radiat. Res. 38,213- 218 (1997).
S. Gouthu, T. Arie, S. Ambe, and I. Yamaguchi:"Screening of plant species for comparative uptake
abilities of radioactive Co, Rb, Sr, and Cs from soil",J. Radioanal. Nucl. Chern. 222,247-251 (1997).
S. Kitayama, M. Kohoroku, A. Takagi, and H. Itoh:"Mutation of D. radiodurans in a gene homologous
to ruvB of E. coh" , Mut. Res. 385, 151-157 (1997).
Y. Ohkubo, S. Uehara, Y. Kawase, J. Nakamura, T.
Okada, S. Ambe, and F. Ambe: "Time-differential
perturbed-angular-correlation studies on 117In andl11Cd in Lio.99sCdo.oosNb03", Phys. Rev. B 56,
10730- 10733 (1997).
S. Gouthu , T. Arie, S. Ambe, and I. Yamaguchi: "Selection of plants for phytoremediation of soil contaminated with radionuclides and the impact of someparameters on plant uptake", Proc. Int. Meet. on
Influence of Climatic Characteristics upon Behaviorof Radioactive Elements, edited by Y. Ohmomo and
N. Sakurai, Institute for Environmental Sciences, pp.
221-228 (1997).
239

H. Wang, S. Ambe, N. Takematsu, and F. Ambe: "Influence of acid rain and organic matter on the adsorption of trace elements on soil", Proc. Sci. Meet.
on Behavior and Distributions of Trace Substancesin the Environment, 1997-12, edited by M. Fukui and
H. Matsuzuru, Res. Reactor Inst., Kyoto Univ., No.
KURRI-KR-18, pp. 33-38 (1997).
K. Ushida, A. Kira, Y. Yoshida, T. Kozawa, S. Tagawa,and H. Shibata: "Self exchange electron transfer andultrafast formation of dimer radical ions", RIKEN
Rev., No. 15, pp. 59-60 (1997).
K. Ushida, A. Kira, Y. Yoshida, T. Kozawa, and S.
Tagawa: "Inter solute hole transfer competing withgeminate ion recombination", RIKEN Rev., No. 15,
pp. 61- 62 (1997).
Y. Hatano and N. Hatano: "Anomalous transport ofions in porous media", RIKEN Rev., No. 15, pp. 9192 (1997).
Y. Kobayashi, Y. Yoshida, K. Hayakawa, K. Yukihira,J. Nakamura, S. Nasu, N. Inabe, Y. Watanabe, A.
Yoshida, M. Kase, A. Goto, Y. Yano, and F. Ambe:"In-beam Mossbauer spectroscopy of 57Fe using a
57Mn beam from RIPS of RIKEN Ring Cyclotron",
RIKEN Rev., No. 16, pp. 21-22 (1997).
S. Ambe and F. Ambe: "Emission Mossbauer spectroscopy of 119Sn using 119Sb as the source nuclide:
Defect studies", RIKEN Rev., No. 16, pp. 33-34(1997).
F. Ambe, T. Okada, and S. Ambe:"Emission
Mossbauer spectroscopy of 11 9 Sn using 119Sb as thesource nuclide: in situ surface studies" , RIKEN Rev.,
No. 16, pp. 37- 38 (1997).
K . Eguchi-Kasai, M. Murakami, H. Itsukaichi, K.
Fukutsu , F. Yatagai, T. Kanai, H. Ohara, and K.
Sato: "Repair of DNA double-strand breaks and cellkilling by charged particles", Adv. Space Res. 22,
543- 549 (1998).
H. Wang, S. Ambe, N. Takematsu, and F. Ambe:"Model study of acid rain effect on adsorption of
trace elements on soils using a multi tracer", J. Radioanal. Nucl. Chern. 235, 295-300 (1998).
T. Shinonaga, S. Ambe, and I. Yamaguchi: "Uptake
rate of trace elements by soybean plants", J. Radioanal. Nucl. Chern. 236, 133- 137 (1998).
S. Ambe, K. Yashiki, H. Maeda, S. Enomoto, T. Ozaki,
and F . Ambe: "Multitracer study on permeation ofrare earth elements through a supported liquid membrane", J. Radioanal. Nucl. Chern. 236 , 181-185(1998).
T. Abe: "The use of heavy-ion beams for mutationinduction", Kagaku To Seibutsu 36, 477-482 (1998).
S. Ambe, T. Shinonaga, T. Ozaki, S. Enomoto, H.
Yasuda, and S. Uchida: "Multitracer study on uptake of elements by komatsuna" , Proc. Int. Meet. on
Influence of Climatic Characteristics upon Behaviorof Radioactive Elements, Rokkashomura, 1997-10,
edited by Y. Ohmomo and N. Sakurai, Institute for240

Environmental Sciences, Japan, pp. 174-180 (1998).
T. Shinonaga, S. Ambe, and I. Yamaguchi: "Uptake and translocation of Sr, Tc, and Cs in soybean plants", Proc. Int. Meet. on Influence of Climatic Characteristics upon Behavior of Radioactive Elements, Rokkashomura, 1997-10, edited by Y.
Ohmomo and N. Sakurai, Institute for Environmental Sciences, Japan, pp. 197-204 (1998).
Y. Ohkubo, S. Uehara, S. Shibata, Y. Kawase, J.
Nakamura, T. Okada, S. Ambe, F. Ambe, K. Asai,
Y. Murakami, and T. Saito: "TDPAC studies on
1171n and 11lCd in Lio.995Cdo.oo5Nb03", Proc. Specialist Res. Meet. on Solid State Physics with Probesof Radiations and Nuclei (II), 1998-02, edited by S.
Nasu, Y. Kawase, and Y. Maeda, Res. Reactor Inst.,
Kyoto Univ., No. KURRI-KR-22, pp. 47-51 (1998).
S. Ambe, T. Okada, and F. Ambe: "In situ emission Mossbauer studies on carrier-free 57 Co 2+ and
119Sb5+ ions at interfaces between spinel-type oxides and aqueous solutions", Radiochim. Acta 80,
101-108 (1998).
T. Shinonaga and S. Ambe: "Multitracer study on absorption of radionuclides in atmosphere-plant model
system", Water, Air, Soil Pollut.
101, 93- 103(1998).
5.

Material analysis

W. Hong, S. Hayakawa, K. Maeda, S. Fukuda, M.
Yanokura, M. Aratani, K. Kimura, Y. Gohshi , and
I. Tanihata: "Development of a high mass-resolution
TOF-ERDA system for a wide mass range from hydrogen to middle heavy elements", Anal. Sci. 13,
365-368 (1997).
K. Katsumata, H. Aruga Katori, S. M. Shapiro, and
G. Shirane: "Neutron-scattering studies of a phasetransition in the metamagnet FeBr2 under external
magnetic fields", Phys. Rev. B 55 , 11466- 11470(1997) .
N. Yamada, T. Fuwa, J. Nakamura, and T. Okada:"Moss bauer study on 57Fe in YSr2Cu3-xFex07+6",
RIKEN Rev., No. 16, pp. 27-28 (1997).
Y. Takano, T. Okada, and T. Yamadaya: "Antiferromagnetic spin clusters in the 2126 type cuprate",
RIKEN Rev., No. 16, pp . 29- 30 (1997).
J. Kawai, N. Inada, and K. Maeda: "X-ray emission
due to charge-up", Adv. X-Ray Chern. Anal. Jpn.
29,203-222 (1998).
K. Maeda, K. Hasegawa, H. Hamanaka, and K.
Ogiwara: "Development of an in-air high-resolution
PIXE system", Nucl. Instrum. Methods Phys. Res.
B 134, 418- 426 (1998).
K. Maeda, K. Hasegawa, H. Hamanaka, and M.
Maeda: "Chemical state analysis in air by highresolution PIXE", N uel. Instrum. Methods Phys.
Res. B 136/138, 994- 999 (1998).

VII. LIST OF PREPRINTS1998
RIKEN-AF-NP
278 K. Varga, J. Usukura, and Y. Suzuki: "Second bound state of the positronium molecule and biexcitons"
279 M. R. Ahmady, V. Elias, and E. Kou: "Nonperturbative QCD contribution to gluon-gluon-eta vertex"
280 H. Kurasawa and T. Suzuki: "Double giant resonance states"
281 H. Kurasawa and T. Suzuki: "Spin dipole states deformed nuclei"
282 N. Saito: "Spin physics with the PHENIX detector system"
283 N. Saito: "High-energy spin physics with RHIC"
284 H. Okamura, S. Ishida, N. Sakamoto, H. Uesaka, T. Wakasa, H. Sakai, T. Niizeki, H. Toyokawa, Y. Tajima,
H. Ohnuma, M. Yosoi, K. Hatanaka, and T. Ichihara: "Mechanism of the forward-angle(d,pn) reaction atintermediate energies"
285 N. D. Dang, K . Tanabe, and A. Arima: "Damping of hot giant dipole resonance due to complex configuration
mixing"286 N. D. Dang, K. Tanabe, and A. Arima: "Contribution of higher-order processes to the damping of hot giant
dipole resonance"
287 T. Horibata, M. Oi, and N. Onishi: "Band crossing studied by GCM with 3D-CHFB"
288 M. Oi, N. Onishi, and T. Horibata: "Wobbling motion in band crossing"
289 Y. S. Mochizuki, S. Kumagai, and I. Tanihata: "The half-life of 44Ti and SN 1987A"
290 N. D. Dang, K. Tanabe, and A. Arima: "Width and shape of hot giant dipole resonance"
291 Y. Ogawa, K. Arai, and K. Varga: "Microscopic four-cluster description of lOBe and lOC with the stochastic
variational method"
292 M. R . Ahmady and E. Kou: "Possible large direct CP asymmetry in hadoronic B± ---+ Jr±r/ decays"
293 N. Hayashi , Y. Goto, and N. Saito: "RHIC spin physics"
294 A. Ozawa, O. Bochkarev, L. Chulkov, D. Cortina, H. Geissel, M. Hellstrom, M. Ivanov, R. Jank, K. Kimura,
T. Kobayashi, A. A. Korsheninnikov, G. Miinzenberg, F. Nickel, Y. Ogawa, A. A. Ogloblin, M. Pfiitzner, V.
Pribora, H. Simon, B. Sitar, P. Strmen, K. Siimmerer, T. Suzuki, I. Tanihata, M. Winkler, K. Yamashita,
and K. Yoshida: "Measurements of interaction cross-sections for carbon isotopes at relativistic energies andthe halo structure 19C"
295 M. R. Ahmady and V. Elias: "Nonperturbative QCD corrections to the effective coefficients of the four-Fermi
operators"
296 N. D. Dang, K. Tanabe, and A. Arima: "Shape evolution of the hot giant dipole resonance"
297 T. Horibata, M. Oi, N. Onishi, and A. Ansari: "Band structures of 1820S studied by GCM based on
3D-CHFB"
298 M. Sambataro and N. D. Dang: "Variational approach to collective excitations"241299 T. Suzuki and H. Sakai: "The landau-migdal parameters, g'NN and g'N~"
300 N. D. Dang, K. Tanabe, and A. Arima: "Damping of double giant dipole resonance"
301 H. Toki and T. Tanihata: "Implication of recent (p, n) spin experiments and the necessity of relativity innuclear physics"
302 K. Kato, T. Yamada, and K . Ikeda: "Dynamical effects on the 9Li-n interaction induced by the pauliblocking of the J7r = 0+ pairing correlation"

RIKEN-AF-NC
4 G. Shirkov and T. Nakagawa: "Numerical simulation of highly charged ion production in RIKEN 18GHz
ECR ion source"
5 G. Shirkov, Y. Batygin, and Y. Yano: "Particle-cell model for numerical simulation of multicomponent ECR
plasma and electron-ion beams"
6 O. Kartavisev and G. Shirkov: "Role of charge exchange processes in the plasma of ECR ion sources"
7 E. Syresin, T. Tanabe, and I. Watanabe: "Simulation of electron and collector for ACR electron coolingsystem"8 I. Meshkov, E. Syresin, T. Katayama, and Y. Yano: "Single turn injection scheme for ACR"
9 T. Katayama, I. Meshkov, A. Sidorin, and E. Syresin: "Electron cooling at DSR"
10 Y. Batygin and T. Katayama: "Luminosity of particle collider"
11 M. Wakasugi, Y. Batygin, N. Inabe, T. Katayama, K. Maruyama, K. Ohtomo, T. Ohkawa, M. Takanaka, T.
Tanabe, I. Tanihata, S. Watanabe, Y. Yano, and K. Yoshida: "Storage rings at RIKEN RI Beam Factory"

242

VIII. PAPERS PRESENTED AT MEETINGS
1.

Accelerator

development

andaccelerator

physics
J.-W. Kim, T. Kubo, and T. Kawaguchi: "A superconducting solenoid for heavy ion beam focusing", 1997
Particle Accelerator Conf. (PAC '97), (IEEE, APS),
Vancouver, Canada, May (1997).
J.-W. Kim, A. Goto, T. Mitsumoto, T. Kubo, H.
Okuno, T. Kawaguchi, T. Tominaka, S. Fujishima,
K. Ikegami, N. Sakamoto, S. Yokouchi, T. Morikawa,and Y. Yano: "'frim coil system for the RIKEN Superconducting Ring Cyclotron", 1997 Particle Accelerator Conf. (PAC'97), (IEEE, APS), Vancouver,
Canada, May (1997).
J.-W. Kim and J. S. Chai: "Design study of a linear accelerator system for neutron capture therapy", 1997
Particle Accelerator Conf. (PAC'97), (IEEE, APS),
Vancouver, Canada, May (1997).
O . Kamigaito, A. Goto, Y. Miyazawa, T. Chiba, M.
Hemmi, S. Kohara, M. Kase, T. Nakagawa, Y.
Batygin, Y. Yano, E. Ikezawa, T. Aihara, T. Ohki,
H. Hasebe, and H. Yamauchi: "Performance testsof a variable-frequency RFQ linac for RILAC", 22nd
Linear Accelerator Meet. in Japan, Sendai, Sept.
(1997).
T. Takagi, S. Fujiwara, K. Wakashima, S. Eguchi,
H. Mukai, and 1. Sakamoto: "Radiation safety control system for SPring-8" , 11th Symp. on Accelerator Science and Technology, (JASRI), Harima, Oct.
(1997).
N. Sakamoto: "Atomic hydrogen beam production at
RIKEN polarized ion source", 14th RIKEN Symp.
on Atomic Physics Using Accelerators: Atomic
Physics with Slow Antiprotons, Wako , Dec. (1997).
A. Goto, Y. Yano, and T. Katayama: "RIKEN RIBeam Factory project", Int. Workshop on Physics
with Radioactive Nuclear Beams, Puri, India, Jan.
(1998) .
1. Tanihata: "RI Beam Factory project" , RIKEN
Symp. on Nuclear Chemistry of Heavy Elements at
RIKEN RI-Beam Factory, Wako, Jan. (1998).
Y. Yoshida, Y. Mizutani, T. Yamamoto, M. Miki ,Y. Izumi, K. Ushida, S. Seki, T. Kozawa, and
S. Tagawa: "Improvement of femtosecond lasersynchronized pulse radiolysis system and its application to ultrafast processes" ,5th Int. Workshop on
Femtosecond Technology, Tsukuba, Feb. (1998).
M. Niimura, A. Goto, and Y. Yano: "Accelerationand heating mechanisms of the hot electron ring
and warm core plasma: The consequence on performance of ECRIS", 1st Asian Particle Accelerator
Conf. (APAC98) , (KEK), Tsukuba, Mar. (1998).
K. Yuasa-Nakagawa: "Reaction mechanism study using total kinetic energy and precision particle multiplicity in medium mass nuclei", RIKEN Symp. on
Dynamics in Hot Nuclei, Wako, Mar. (1998).

T. Tominaka, K. Kusaka, and T. Kubo: "Design
study of the superconducting quadrupole magnets
for RIKEN Big RIPS (1)", 58th Meet. on Cryogenics and Superconductivity, (Cryogenic Association ofJapan), Fujisawa, May (1998).
T. Tominaka, H. Okuno, S. Fujishima, A. Goto, and Y.
Yano: "Optimization of the superconducting dipole
coils for injection system of superconducting ring
cyclotron", 58th Meet. on Cryogenics and Superconductivity, (Cryogenic Association of Japan), Fujisawa, May (1998).
K. Ohtomo and T. Katayama: "Injection simulation study at accumulator cooler ring at RI Beam
Factory", 6th European Particle Accelerator Conf.,(Manne Siegbahn Laboratory), Stockholm, Sweden,
June (1998).
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 superconduction Ring Cyclotron of RIKEN
RI Beam Factory", 15th Int. Conf. on Cyclotrons
and Their Applications (Cyclotrons'98), (GANIL),
Caen, France, June (1998).
T. Tominaka, H. Okuno, S. Fujishima, A. Goto, andY. Yano: "An optimal design for the injection andextraction elements for the RIKEN Superconducting
Ring Cyclotron", 15th Int. Conf. on Cyclotrons andTheir Applications (Cyclotrons'98), (GANIL), Caen,
France, June (1998).
A. Goto, J.-W. Kim, J. Ohnishi, T. Kawaguchi, H.
Okuno, S. Fujishima, T. Tominaka, and Y. Yano:"Orbit analysis of the RIKEN Superconducting Ring
Cyclotron", 15th Int. Conf. on Cyclotrons andTheir Applications (Cyclotrons'98), (GANIL), Caen,
France, June (1998).
S. Kohara, Y. Miyazawa, O. Kamigaito, T. Chiba,
E. Ikezawa, M. Kase, and A. Goto: "Model studyof a resonator for a flat-top acceleration system in
the RIKEN AVF Cyclotron" , 15th Int. Conf. on
Cyclotrons and Their Applications (Cyclotrons'98),(GANIL) , Caen, France, June (1998).
S. Fujishima, H. Okuno, T. Tominaka, T. Mitsumoto,
A. Goto, and Y. Yano: "Analysis of the injection andextraction trajectories in the RIKEN Superconducting Ring Cyclotron", 15th Int. Conf. on Cyclotrons
and Their Applications (Cyclotrons'98) , (GANIL),
Caen, France, June (1998).
H. Shibata, K. Kobayashi, T. Iwai, M. Narui, T.
Ornata, S. Sasaki, Y. Hamabe, A. Fujiwara, S.
Hasegawa, T. Nishimura, H. Yano, H. Ohashi, and
K. Nogami: "Experiment for dust acceleration",
23rd Ann. Meet. of the Society for Atomic Collision Research, Yokohama, Aug. (1998).
O. Kamigaito, A. Goto, Y. Miyazawa, T. Chiba,
M. Hemmi, M. Kase, S. Kohara, E. Ikezawa, T.
243

Nakagawa, M. Kidera, and Y. Yano: "Recent developments of the folded-coaxial RFQ for the RIKEN
Heavy Ion Linac", 19th Int. Linac Conf., (ANL,
FNAL), Chicago, USA, Aug. (1998).
O. Kamigaito, A. Bandyopadhyay, M. Kase, Y.
Miyazawa, T . Chiba, M. Hemmi, S. Kohara, E.
Ikezawa, A. Goto, Y. Yano, and A. Bandyopadhyay:"Design of a charge-state multiplier system for the
RIKEN RI-Beam Factory", 19th Int. Linac Conf.,(ANL, FNAL), Chicago, USA, Aug. (1998).
O. Kamigaito, M. Kase, Y. Miyazawa, T . Chiba, M.
Hemmi, E. Ikezawa, S. Kohara, A. Goto, and Y.
Yano: "Development of a charge-state multiplier system for the RIKEN RI-Baem Factory" , 23rd Linear
Accelerator Meet. in Japan, (Electrotechnical Laboratory), Tsukuba, Sept. (1998).
M. Niimura, A. Goto, and Y. Yano: "Study of the
hot-electron acceleration and warm-electron heating
mechanisms in an ECR ion source for high-brightness
hadron colliders" , High Energy Accelerator Conf.
(HEACC'98), (Joint Institute of Nuclear Research),
Dubna, Russia, Sept. (1998).
T. Kawaguchi, T . Nakagawa, and T. Kurita: "Development of a He-free SCM for ECR ion source",
59th Meet. on Cryogenics and Superconductivity,(Cryogenics Association of Japan) , Yamaguchi, Oct.
(1998) .
T. Kawaguchi, H. Okuno, A. Goto, and Y. Yano: "Development of the sector magnets for the Superconducting Ring Cyclotoron", 59th Meet. on Cryogenics and Superconductivity, (Cryogenics Associationof Japan), Yamaguchi, Oct. (1998).
T. Tominaka, M. Okamura, T. Kawaguchi, and T.
Katayama: "R&D of helical dipole magnets", 59th
Meet. on Cryogenics and Superconductivity, (Cryogenics Association of Japan), Yamaguchi, Oct.
(1998).
T. Tominaka, H. Okuno, S. Fujishima, A. Goto, and Y.
Yano: "Optimization of the superconducting dipole
coils for injection system of Superconducting Ring
Cyclotron(2)" , 59th Meet. on Cryogenics and Superconductivity, (Cryogenics Association of Japan),
Yamaguchi, Oct. (1998).
Y. Mizutani, A. Saeki, K. Okamoto, M. Miki, S. Seki,
T . Kozawa, K. Ushida, Y. Yoshida, and S. Tagawa:"Development of picosecond pulse radiolysis by using
femtosecond laser synchronized with L- band linac",
41st Symp. on Radiation Chemistry, (Japanese Society of Radiation Chemistry), Kobe, Oct. (1998).
H. Shibata, K . Kobayashi, T. Iwai, M. Narui, T.
Ornata, S. Sasaki, Y. Hamabe, A. Fujiwara, S.
Hasegawa, T. Nishimura, H. Yano, H. Ohashi, and
K. Nogami: "Design of electrostatic acceleration system for microparticles to hypervelocites and its application" ,41st Symp. on Radiochemistry and AsiaPacific Symposium on Radiochemistry, (The Chemical Society of Japan), Kobe, Oct. (1998).
244

2.

Nuclear physics and nuclear instrumentation

T. Motobayashi: "New measurement of 8B Coulomb
dissociation and E2 component", 4th Int. Conf. onRadioactive Nuclear Beams (RNB4), Omiya, June
(1996) .
T. Motobayashi: "Measurement of the E2-component
in the Coulomb dissociation of BB", 4th Int. Symp.
on Nuclear Astrophysics (NIC96), (Notre Dame University), Notre Dame, USA , June (1996).
T. Motobayashi: "Radiative capture process of astrophysical interest studied by Coulomb dissociation of
unstable nuclei" ,9th Int. Symp. on Capture, Rays
Spectroscopy and Related Topics (cgs9), Budapest,
Hungary, Oct. (1996).
K. Asahi: "Polarized heavy ions and their application", 7th RCNP Int. Workshop on Polarized
3He Beams and Gas Targets and Their Application,
Kobe, Jan. (1997).
T. Matsuzaki, K. Nagamine, K. Ishida, S. N.
Nakamura, N. Kawamura, S. Sakamoto, M. Tanase,
M. Kato, K. Kurosawa, M. Hashimoto, K. Kudoh, N.
Takeda, and G. H. Eaton: "Muon catalyzed fusion
research at RIKEN-RAL Muon Facility: (5)Target
gas purification system and He-3 accumulation effect" , 52nd Ann. Meet. of Physical Society of Japan,
Nagoya, Mar. (1997).
K. Yoshida: "Search for super heavy compound nuclei", RIKEN Symp. on Dynamics in Hot Nuclei,
Wako, Mar. (1997).
H. Sakurai: "RIBF-facility development and unstable
nuclear physics", Symp. on RI Beam Factory andAstrophsics, Wako, Apr. (1997).
Y. Mochizuki: "Neutron stars and RI Beam Factory",
Symp. on RI Beam Factory and Astrophysics, Wako,
Apr. (1997).
T. Kishida: ",-ray detector for RI Beam Factory",
Workshop on Physics in RI Beam Factory, Wako,
May (1997).
H. Sakurai: "Particle identification and new isotope
search", Workshop on Physics in RI Beam Factory,
Wako, May (1997).
H. Sakurai: "Nuclear mass measurement", Workshop
on Physics in RI Beam Factory, Wako, May (1997).
Y. Gono: "Position sensitive gamma-ray detection",
3rd Japan China Joint Nuclear Physics Symp. on
Recent Topics in Nuclear Physics, Sendai, June
(1997) .
N. Saito: "Spin physics at PHIC", 1997 QCD in Nuclear Physics Gordon Research Conf., (Salve Regina
University in Newport, RI), Rhode, Island, July
(1997) .
T. Otsuka, T. Mizusaki, and M. Honma: "Monte-Carloshell model calculations", 3rd Japan China Joint Nuclear Physics Symp. on Recent Topics in Nuclear
Physics, Sendai, July (1997).
K. Asahi, K. Sakai, H. Ogawa, A. Yoshimi , M. Tsuda,
Y. Uchiyama, T. Suzuki, K. Suzuki, N. Kurokawa, H.

Sato, M. Adachi, A. Yoshida, S. Fukuda, T. Kubo, H.
Okuno, N. Fukunishi, M. Notani, N. Aoi, K. Yoneda,
H . Iwasaki, N. Fukuda, M. Ishihara, H. Izumi, H.
Deno, T. Shimoda, S. Tanimoto, N. Takahashi, W.D. Schmidt-Ott, and M. Schafer: "Experiments withpolarized RI Beam Factory at RIKEN", 3rd Japan
China Joint Nuclear Physics Symp. on Recent Topics in Nuclear Physics, Sendai, July (1997).
T. Nakamura: "Coulomb excitation of 11 Be", 3rdJapan China Joint Nuclear Physics Symp. on Recent Topics in Nuclear Physics, Sendai, July (1997).
H. Sakurai: "New neutron-rich nuclei isotopes close to
the neutron drip-line", 3rd Japan China Joint Nuclear Physics Symp. on Recent Topics in Nuclear
Physics, Sendai, July (1997).
Y. Ogawa: "The momentum distributions of the corefragment from the nuclear breakup reaction within
the glauber model", 3rd Japan China Joint Nuclear
Physics Symp. on Recent Topics in Nuclear Physics,
Sendai, July (1997).
K. Nagamine: "Muon catalyzed fusion", 9th TRIUMF
Summer Institute, Vancouver, Canada, July (1997).
T. Kishida: "RI Beam Factory and -y-ray detector",
Workshop on ! Spectroscopy with Using Heavy Ion. Photon· RI Beam, TOkai-mura, July (1997).
Y. Mochizuki, T. Izuyama, 1. Tanihata, and K.
Oyamatsu: "Exotic nuclear rod form ation for theorigin of neutron star glitches", 1997 Pacific Rim
Conf. on Stellar Astrophysics , Hong Kong, China,
Aug. (1997).
Y. Mochizuki and S. Kumagai: "The half-life of titanium 44 and supernova remnants", Int. Astronomical Union General Meet., Symp. No. 188, Kyoto,
Aug. (1997).
K. Sumiyoshi, Y. Sugahara, D. Hirata, 1. Tanihata,
and H. Toki: "Light unstable nuclei in relativistic mean field theory", Workshop for Physics of RI
Beams: Physics of Cluster in Unstable Nuclei, Wako,
Aug. (1997).
H. Ogawa, K. Asahi, K. Sakai, M. Tsuda, A. Yoshimi,
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, T. Kubo , H.
Okuno, H. Sato, M. Notani, N. Aoi, K. Yoneda, H.
Iwasaki, N. Fukuda, M. Ishihara, and H. Miyatake:"Measurement of the magnetic moment and electric
quadrupole moment of a neutron-rich nucleus 18N",
1997 Fall Meet. of Physical Society of Japan , Hachioji, Sept. (1997).
N. Saito: "High energy spin physics with using RHIC" ,1997 Fall Meet. of Physical Society of Japan, Hachioji, Sept. (1997).
K. Yoshida, M. Shimooka' T. Nakagawa, K. Nakagawa,1. Tanihata, R. Wada, Y. Aoki, and J. Kasagi: "Construction of a large area PPAC/ion chamber", 1997
Fall Meet. of Physical Society of Japan, Hachioji ,Sept. (1997).

K. Kusaka and H. Toki: "Non-perturbative renormalization of the fermion mass term in the DysonSchwinger equation", 1997 Fall Meet. of PhysicalSociety of Japan, Hachioji, Sept. (1997).
Y. Mochizuki, T . Izuyama, 1. Tanihata, and K.
Oyamatsu: "Pycnonuclear fusion reactions as theorigin of neutron star glitches", 1997 Fall Meet. ofPhysical Society of Japan, Hachioji, Sept. (1997).
I. Imaida, Y. Muraki, Y. Matsubara, K. Masuda,
T. Koi, H. Tsuchiya, T. Hoshida, T. Goka, H.
Matsumoto, T. Omoto, A. Takase, K. Taguchi, M.
Nakazawa, 1. Tanaka, M. Fujii, T. Kohno, H. Ikeda,
and T. Sako: "Beam experiment results of multi anode neutron sensor", 1997 Fall Meet. of PhysicalSociety of Japan, Hachioji, Sept. (1997).
H. Miyasaka, I. Yamagiwa, C. Kato, T. Goka, and H.
Matsumoto: "Observation results of heavy ions withADEOS satellite", 1997 Fall Meet. of Physical Society of Japan, Hachioji, Sept. (1997).
H. Sakurai: "New neutron-rich nuclei found with a 70A
MeV 48Ca beam", 6th Int. School-Seminar, HeavyIon Physics, Dubna, Russia, Sept. (1997).
T. Suzuki, H . Geissel, O. Bochkarev, L. Chulkov,
M. Golovkov, D. Hirata, H. Irnich, Z. Janas, H .
Keller, T. Kobayashi, G. Kraus, G. Muenzenberg, S.
Neumaier, F. Nickel, A. Ozawa, A. Piechaczeck, E.
Roeckl , W. Schwab, K. Suemmerer, K. Yoshida, and
I. Tanihata: "Neutron skin of Na isotopes and an
application to the EOS", 6th Int. School-Seminar,
Heavy-Ion Physics, Dubna, Russia, Sept. (1997).
T. Otsuka, T. Mizusaki, Y. Utsuno, and M. Honma:"Stochastic approach to nuclear shell model", Int.
Symp. on Atomic Nuclei and Metallic Clusters: Finite Many-Fermion Systems, Praque, Czech, Sept.
(1997).
T. Matsuzaki, K. Ishida, S. N. Nakamura, N.
Kawamura, and K. Nagamine: "Muon catalyzed
fusion research at RIKEN-RAL Muon Facility",
RIKEN Symp. on Muon Science '97: Muon Condensed Matter Studies and Muon Catalyzed Fusion,
Wako, Sept. (1997).
K. Nagamine, T. Matsuzaki, K. Ishida, S. N.
Nakamura, and N. Kawamura: "Experimental resultof RIKEN-RAL Muon Facility: Muon catalyzed fusion", RIKEN Symp. on Muon Science '97: Muon
Condensed Matter Studies and Muon Catalyzed Fusion, Wako, Sept. (1997).
H. Sakurai: "Research with radioactive beams at
RIKEN", School-Seminar on RI Beams, Lanzhou,
China, Sept. (1997).
K. Nagamine: "Muon science", UK-Japan Collaboration Assisted by The British Council, Tokyo, Sept.
(1997).
T. Kohno and H. Miyasaka: "Heavy ion observation with ADEOS satellite", Workshop on Dynamics of Magnetospheric High Energy Particles at
Solar Terrestrial Environment Laboratoly, (SolarTerrestrial Environment Laboratory, Nogoya Univer245

sity), Nagoya, Sept. (1997).
Y. Suda, Y. Ogawa, H. Iwasa, F. Hiraga, T.
Kamiyama, Y. Kiyanagi, T. Oku, H. Kato, H. M.
Shimizu, and T. Wakabayashi: "Focus of cold neutron beam using neutron lens", 1997 Fall Meet. of
the Atomic Energy Society of Japan, Ginowan, Oct.
(1997).
T. Otsuka, T . Mizusaki, Y. Utsuno, and M. Honma:"Monte Carlo shell model calculations for stable andunstable nuclei", 3rd INFN-RIKEN Meet. on Perspectives in Heavy Ions Physics, (Padova Univ. andNational Laboratories of Legnaro) , Padova, Italy,
Oct. (1997).
T. Kishida: "RI Beam Factory Project at RIKEN",
3rd INFN-RIKEN Meet. on Perspectives in Heavy
Ions Physics, (Padova Univ. and National Laboratories of Legnaro), Padova, Italy, Oct. (1997).
M. Ishihara: "Direct reaction spectroscopy of very neutron rich nuclei", 3rd INFN-RIKEN Meet. on Perspectives in Heavy Ions Physics , (Padova Univ. andNational Laboratories of Legnaro), Padova, Italy,
Oct. (1997).
T. Nakamura: "Coulomb dissociation of halo nuclei" ,3rd INFN-RIKEN Meet. on Perspectives in Heavy
Ions Physics, (Padova Univ. and National Laboratories of Legnaro), Padova, Italy, Oct. (1997).
Y. Gono: "HSIB and Ge-telescope", 3rd INFNRIKEN Meet. on Perspectives in Heavy Ions Physics,(Padova Univ. and National Laboratories of Legnaro) , Padova, Italy, Oct. (1997).
K. Asahi, H. Ogawa, K. Sakai, A. Yoshimi, M. Tsuda,
Y. Uchiyama, T. Suzuki, K. Suzuki, N. Kurokawa,
H. Sato, M. Adachi, H. Izumi, H. Ueno, T. Shimoda,
S. Tanimoto, N. Takahashi, W. D. Schmidt-Ott, M.
Schafer, S. Fukuda, A. Yoshida, T. Kubo, H. Okuno,
N. Fukunishi, M. Notani, N. Aoi, K. Yoneda, H.
Iwasaki, N. Fukuda, and M. Ishihara: "Recent results of nuclear moment measurements with polarized radioactive beams", 3rd INFN-RIKEN Meet. on
Perspectives in Heavy Ions Physics , (Padova Univ.
and National Laboratories of Legnaro), Padova,
Italy, Oct. (1997).
A. Ozawa: "Measurement of interaction cross sections for light neutron rich nuclei", 3rd INFNRIKEN Meet. on Perspectives in Heavy Ions Physics,(Padova Univ. and National Laboratories of Legnaro), Padova, Italy, Oct. (1997).
Y. Mochizuki: "A microscopic model of glitches: N uclei and superfluidity inside neutron stars", Astrophysics Seminar at Tokyo-Metropolitan University,
Tokyo, Oct. (1997).
T. Kohno, H. Miyasaka, I. Yamagiwa, C. Kato, T.
Goka, and H. Matsumoto: "Observation results ofheavy ions with ADEOS satellite", Plenary Meet. ofSociety of Geomagnetic and Planetary Physics, Sapporo, Oct. (1997).
Y. Ogawa: "The momentum distributions of the corefragment from the nuclear breakup reaction within
246

the glauber model", Structure and Reaction of Unstable Nuclei, Kyoto, Oct. (1997).
T. Kohno, T . Goka, and H. Matsumoto: "Heavy ion
observation with ADEOS satellite", Workshop on
Space Radiation Environment Modelling: New Phenomena and Approaches, (Skobeltsyn Institute of
Nuclear Physics of Moscow State University, RusianFoundation for Fundamental Research, COSPAR),
Moscow, Russia, Oct. (1997).
T. Nakamura: "Coulomb excitation of neutron richhalo nuclei", YITP Workshop on Structure and Reaction of Unstable Nuclei, Kyoto, Oct. (19.97).
Y. Mochizuki, T. Izuyama, I. Tanihata, and K.
Oyamatsu: "A microscopic model of neutron starglitches", Int. Conf. on Neutron Stars and Pulsars:
Thirty Years after the Discovery, (Rikkyo University), Tokyo, Nov. (1997).
T. Otsuka and T. Suzuki: "Spin-isospin degree of freedom in unstable nuclei", Int. Symp. on New Facetof Spin Giant Resonances in Nuclei, (University ofTokyo), Tokyo, Nov. (1997).
T. Teranishi, S. Shimoura, Y. Ando, M. Hirai, N.
Iwasa, T. Kikuchi, S. Moriya, T. Motobayashi, H.
Murakami, T. Nakamura, T. Nishio, H. Sakurai,
T. Uchibori, Y. Watanabe, Y. Yanagisawa, and M.
Ishihara: "Isobaric analog state of 11 Li (experiment)", Int. Symp. on New Facet of Spin Giant
Resonances in Nuclei, (University of Tokyo), Tokyo,
Nov. (1997).
H. Okamura, T. Wakasa, Y. Satou, T. Ohnishi, T.
Nonaka, H. Sakai, S. Ishida, N. Sakamoto, T. Uesaka,
T. Ichihara, T. Niizeki, and H. Ohnuma: "Spindipole resonance studied by the (d~2He) reaction",
Int. Symp. on New Fact of Spin Giant Resonancesin Nuclei, (University of Tokyo), Tokyo, Nov. (1997).
Y.
Mochizuki, S. Kumagai, K. Nomoto, and I.
Tanihata: "The half-life of 44Ti and supernova remnants", Int. Symp. on Origin of Matter and Evolution of Galaxies 97, Atami, Nov. (1997).
K. N agamine: "Recent progress in muon catalyzed fusion and related muon science: Muons for humanlife", Oxford Physics Colloquium, (Oxford U niversity), Oxford, UK, Nov. (1997).
Y. Utsuno, T. Mizusaki, T. Otsuka, and M. Honma:"Structure of unstable nuclei studied by Monte Carloshell model", 17th RCNP Int. Symp. on Innovative Computational Methods in Nuclear Many-Body
Problems, (RCNP), Osaka, Nov. (1997).
Y. Ogawa: "The momentum distributions of the corefragment from the nuclear breakup reaction within
the glauber model", 17th RCNP Int. Symp. on Innovative Computational Methods in Nuclear ManyBody Problems, Osaka, Nov. (1997).
Y. Mao: "SPIN experiment at PHENIX", RIKEN
Symp. on Quarks and Gluons in the Nucleon, Wako,
Nov. (1997).
T. Otsuka, T. Mizusaki, Y. Utsuno, and M. Honma :"Monte Carlo shell model calculations for proton-rich and neutron-rich unstable nuclei", Workshop
on the Structure of Atomic Nuclei in Exotic States,(GANIL), Caen, France, Nov. (1997).
Y. Mochizuki: "A microscopic model of glitches: Nuclei and superfluidity inside neutron stars", Hadron
Transfer Group Seminar at Japan Atomic Energy
Research Institute, Tokai-mura, Dec. (1997).
N. Saito and Collaboration Phenix: "Spin physics
with the PHENIX detector system", 13th Int. Conf.
on Ultra Relativistic Nucleus-Nucleus Collisions,
Tsukuba, Dec. (1997).
D. Kharzeev: "Summary theoretical interpretations of
J/\I! suppression", Quark Matter '97, Tsukuba, Dec.
(1997).
K. Nagamine: "New directions in muon atomic physics
research", 14th RIKEN Symp. on Atomic Physics
Using Accelerators: Atomic Physics with Slow Antiprotons, Wako, Dec. (1997).
1. Tanihata: "RI Beam Factory project", RIKEN
Symp. on Materials Science in RIKEN RI Beam
Factory, Wako, Dec. (1997).
Y. Kobayashi, Y. Yoshida, A. Yoshida, Y. Watanabe,
N. Aoi, K. Hayakawa, K. Yukihira, S. Nasu, J.
Nakamura, and F . Ambe: "In-Beam Mossbauer
spectroscopy for materials science at RIKEN Accelerator Research Facility", Specialist Res. Meet. on
Solid State Physics with Probes of Radiations andNuclei, (Kyoto University), Kumatori, Dec. (1997).
K. Nagamine: "Recent progress in muon catalyzed fusion and related muon science: Muons for humanlife", Birmingham University Colloq., Birmingham,
UK, Jan. (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 measurementof the drip line nuclei 19B, 22C and 23N" ,Int. Workshop on Physics with Radioactive Nuclear Beams,
Puri, India, Jan. (1998).
T. Motobayashi: "Coulomb excitation studies with radioactive nuclear beams" , Int. Workshop on Physics
with Radioactive Nuclear Beams, Puri , India, Jan.
(1998).
T. Motobayashi: "Coulomb dissociation studies for
astrophysical thermonuclear reactions", Int. Workshop XXVI on Gross Properties of Nuclei and Nuclear Excitations, Hirschegg, Austria, Jan . (1998).
'K. Morita: "Experiment for Synthesising heavy elements at RIKEN", RIKEN Symp. on Nuclear Chemistry of Heavy Elements at RIKEN RI-Beam Factory,
Wako, Jan. (1998).
T. Matsuzaki, K. Nagamine, K. Ishida, and S.
N. Nakamura: "Muon catalyzed fusion research
at RIKEN-RAL Muon Facility", RIKEN Symp.
on Studies on Condensed Matter Physics, Atomic
Physics, Nuclear Chemistry, and Biology andMedicine Using RIKEN Acccelerators, Wako, Jan.
(1998).

H. Sakurai: "Search for new neutron-rich isotopes",
6th RIKEN Winter School, Kusatsu, Jan. (1998).
Y. Satou, S. Ishida, H. Sakai, H. Okamura, H. Otsu,
N. Sakamoto, T. Uesaka, T. Wakasa, T . Ohnishi,
T. Nonaka, G. Yokoyama, T. Ichihara, T. Niizeki,
K. Ito, K. Sekiguchi, K. Yako, S. Fukusaka, and K.
Hatanaka: "Measurement of the 28Si(d~ J) reactionat Ed=270 MeV", 53rd Ann. Meet. of Physical Society of Japan, Funabashi, Mar. (1998).
H. Iwasaki: "E2 strength of neutron-rich neuclei 12Be",
53rd Ann. Meet. of Physical Society of Japan, Funabashi, Mar. (1998).
T. Motobayashi, T. Kikuchi, N. Iwasa, Y. Ando, M.
Kurokawa, S. Moriya, H. Murakami, T. Nishio, S.
Shirato, S. Shimoura, T. Uchibori, Y. Yanagisawa,
T. Kubo, H. Sakurai, T. Teranishi, Y. Watanabe,
M. Ishihara, M. Hirai, T. Nakamura, S. Kubono, M.
Gai, R. H. III France, K. 1. Hahn, Th. Delbar, P.
Lipnik, C. Michotte, and J .-Z. Ruan: "S-factor determination of solar neutrino reaction ,7Be(p,,)8B",
53rd Ann. Meet. of Physical Society of Japan, Funabashi, Mar. (1998).
T. Matsuzaki, K. Nagamine, K. Ishida, S. N.
Nakamura, N. Kawamura, S. Sakamoto, M. Tanase,
M. Kato, K. Kurosawa, K. Kudoh, N. Takeda, G.
H. Eaton, M. Hashimoto, and H. Sugai: "Muon catalyzed dt fusion research at RIKEN-RAL Muon Facility(8): Pure T2 Target", 53rd Ann. Meet. ofPhysical Society of Japan, Funabashi, Mar. (1998).
S. N. Nakamura, K. Nagamine, T. Matsuzaki, K.
Ishida, N. Kawamura, S. Sakamoto, M. Tanase, M.
Kato, K. Kurosawa, M. Hashimoto, H. Sugai, K.
Kudoh, N. Takeda, and G. H. Eaton: "Muon catalyzed dt fusion research at RIKEN-RAL Muon Facility (9): High tritium concentration DT target",53rd Ann. Meet. of Physical Society of Japan, Funabashi, Mar. (1998).
Y. Mochizuki, T. Izuyama, 1. Tanihata, and K.
Oyamatsu: "A microscopic model of neutron starglitches", Ann. Meet. of Astronomy Society ofJapan, Hachioji, Mar. (1998).
Y. Mochizuki and 1. Tanihata: "The half-life of 44Ti
and supernova remnants", Ann. Meet. of PhysicalSociety of Japan, Funabashi, Mar. (1998).
K. Ishida: "Solenoid capture/phase rotation simulation at RIKEN /RAL", Int. Workshop on JHF Science (JHF98), (KEK), Tsukuba, Mar. (1998).
T. Otsuka: "What are interesting in nuclear physics?",
Int. Workshop on JHF Science (JHF98), (KEK),
Tsuku ba, Mar. (1998) .
K. Ishida: "Beams in future-solenoid capture at
RIKEN /RAL", Int. Workshop on JHF Science(JHF98), (KEK), Tsukuba, Mar. (1998).
T . Otsuka, T. Mizusaki, Y. Utsuno, and M. Honma:"Monte Carlo shell model calculations", Int. Workshop on Mean-Field Methods in Low-Energy Nuclear
Structure, (ECT*) , Trento, Italy, Mar. (1998).
247

K. Sumiyoshi: "Systematic study of structure of unstable nuclei: Quest for the shape of nucleus", RIKEN
Symp. on Computational Science with Supercomputer and Special-Purpose, Wako, Mar. (1998).
K. Varga: "Applications of the stochastic variational
method", RIKEN Symp. on Computational Science
with Supercomputer and Special-Purpose, Wako,
Mar. (1998).
K. Sumiyoshi, S. Sugimoto, D. Hirata, H. Toki, and 1.
Tanihata: "Systematic study of structure of unstable nuclei: Shape of nuclei" , RIKEN Symp. on Computational Science with Supercomputer and SpecialPurpose, Wako , Mar. (1998).
K. Sugawara-Tanabe and K. Tanabe: "Some aspects
in thermal field theory and its application" , RIKEN
Symp. on Dynamics in Hot Nuclei, Wako, Mar.
(1998).
N. Dinh Dang and A. Arima: "Temperature dependence of quantal and thermal dampings of hot giant
dipole resonance", RIKEN Symp. on Dynamics in
Hot Nuclei, Wako, Mar. (1998).
S. Yamaji: "Temperature dependence of friction",
RIKEN Symp. on Dynamics in Hot Nuclei , Wako ,Mar. (1998).
K. Yoshida: "Search for super heavy compound nuclei", RIKEN Symp. on Dynamics in Hot Nuclei ,Wako, Mar. (1998).
H. Sakurai: "New neutron rich isotopes close to theneutron drip line" , RIKEN Symp. on Dynamics in
Hot Nuclei, Wako, Mar. (1998).
T. Matsuzaki, K. Ishida, S. N. Nakamura, N.
Kawamura, and K. Nagamine: "Results on muon
catalyzed fusion experiments in solid/liquid D-T and
T2 at RIKEN-RAL" , RIKEN Symp. on Muon Life
Science, Muon Catalyzed Fusion and Muon Fundamental Physics, Wako, Mar. (1998).
K. Ishida: "Muon catalyzed fusion (J.LCF) experimentat the RIKEN-RAL Muon Facility: (1) X-ray andneutron measurement of J.L to Q sticking probability",
Symp. on Laser Application to Muon Science, (Meson Science Laboratory, IMSS, KEK(KEK-MSL)) ,Tsukuba, Mar. (1998).
T. Matsuzaki: "Facility and Apparatus for muon catalyzed fusion research at RIKEN-RAL Muon Facility", Symp. on Laser Muon Science, (KEK) ,Tsukuba, Mar. (1998).
N. Dinh Dang, K. Tanabe, and A. Arima: "Temperature dependence of quantal and thermal dampingsof the hot giant dipole resonance", 6th Int. Spring
Seminar on Nuclear Physics 'Highlights in Modern
Nuclear Structure' , (INFN Napoli and Universita di
Napoli), Varenna, Italy, May (1998).
Y. Satou, S. Ishida, H. Sakai, H. Okamura, H. Otsu,
N. Sakamoto, T. Uesaka, T. Wakasa, T . Ohnishi,
T. Nonaka, G. Yokoyama, T. Ichihara, T. Niizeki,
and N. Nishimori: "Study of isoscalar spin strength
via the 12C (d~ d) reaction", Topical Conf. Giant
Resonances, (Istituto N azionale di Fisica N ucleare),248

Varenna, Italy, May (1998) .
N. Dinh Dang, K. Tanabe, and A. Arima: "Temperature dependence of quantal and thermal dampingsof the hot giant dipole resonance" , Topical Conf. on
Giant Resonances, (Istituto Nazionale di Fisica Nucleare), Varenna, Italy, May (1998).
K. Sugawara-Tanabe, A. Arima, and N. Yoshida: "Thedeformation effect on the pairing gap", Int. Conf. on
Nuclear Structure at the Extremes, Lewes, UK, June
(1998).
K. Sugawara-Tanabe, A. Arima, S. Yamaji, and J.
Meng: "The pseudo-spin symmetry in Dirac equation", Int. Conf. on Nuclear Structure at the Extremes, Lewes, UK, June (1998).
T. Horibata, M. Oi, and N. Onishi: "Band crossing
studied by GCM with 3D-CHFB", Nuclear Structure
at the Extremes, Lewes, UK , June (1998).
T. Goka, H. Matsumoto, S. Takagi, and T. Kohno:"Empirical radiation belt models based on theJapanese satellites measurements", 1998 Western
Pacific Geophysics Meet. , (American GeophysicalUnion), Taipei, Taiwan, July (1998).
T. Kohno, H. Miyasaka, C. Kato, 1. Yamagiwa, T.
Goka, and H. Matsumoto: "Heavy ion observation with MIDORI satellite", 1998 Western PacificGeophysics Meet., (American Geophysical Union),
Taipei, Taiwan, July (1998).
K. Nagata, T. Kohno, H. Murakami, A. Nakamoto, N.
Hasebe, J. Kikuchi, and T. Doke: "Pitch angle distributions of the low latitude precipitation electrons" ,1998 Western Pacific Geophysics Meet., (American
Geophysical Union), Taipei, Taiwan, July (1998).
H. Miyasaka, T. Kohno, 1. Yamagiwa, H. Kato, C.
Kato, T. Goka, and H. Matsumoto: "Observation oftrapped anomalous cosmic rays with MIDORI satellite" , 32nd COSPAR Scientific Assembly, (The International Council of Scientific Unions), Nagoya, July
(1998).
C. Kato, K. Munakata, T. Kohno, H. Miyasaka, 1.
Yamagiwa, T. Goka, and H. Matsumoto: "Pitch angle distribution of He observed at MIDORI satellite" , 32nd COSPAR Scientific Assembly, (The International Council of Scientific Unions), Nagoya, July
(1998).
G.1. Pugacheva, A. A. Gusev, T. Kohno, 1. M. Martin,and W. Spjeldvik: "An investigation of the spatial
and time variations of the energetic trapped helium
ions with Japanese OHZORA and AKEBONO satellites", 32nd COSPAR Scientific Assembly, (The International Council of Scientific Unions) , Nagoya,
July (1998).
A. A. Gusev, T. Kohno, 1. M. Martin, G. 1. Pugacheva,
and W. Spjeldvik: "The spatial distribution and dynamics of MEV proton fluxes under earth's radiation belt", 32nd COSPAR Scientific Assembly, (TheInternational Council of Scientific Unions), Nagoya,
July (1998).

K. Uchiyama, M. Sugita, and K. Furuno: "Systematic study of B(E2; ot -+ 2t) for the Ba isotopes",
JAERI Symp. on Frontier of Gamma-Ray Spectroscopy, (Japan Atomic Energy Research Institute) ,Tokai-mura, July (1998).
H. Madokoro, J. Meng, M. Matsuzaki, and S. Yamaji:"Relativistic mean field description of the identicalbands and band crossing in superdeformed Eu-Gd
nuclei", JAERI Symp . on Frontier of Gamma-Ray
Spectroscopy, (Japan Atomic Energy Research Institute), Tokai-mura, July (1998).
K. Ishida, K. Nagamine, T. Matsuzaki, S. N.
Nakamura, N. Kawamura, S. Sakamoto, M. Iwasaki,
M. Tanase, M. Kato, K. Kurosawa, H. Sugai, I.
Watanabe, K. Kudoh, N. Takeda, and G. H. Eaton:"Measurement of X-rays from muon to alpha sticking
and fusion neutrons in solid/liquid D-T mixtures ofhigh tritium concentration" , Monte Verita Workshop
on Exotic Atoms, Molecules and Muon Catalyzed
Fusion, (Paul Scherrer Institute and the University
of Fribourg), Ascona, Switzerland, July (1998).
S. N. Nakamura, K. Bartlett, G. A. Beer, D. R. Gill,
R. S. Hayano, T. M. Ito, M. Iwasaki, L. Lee, G.
Mason, A. Olin, H. Outa, M. Salomon, R . Seki, T.
Taniguchi, T. P. Terada, G. Trayling, Y. Yamashita,
and S. Yen: "Observation of kaonic hydrogen atom
X rays", Monte Verita Workshop on Exotic Atoms,
Molecules and Muon Catalyzed Fusion, (Paul Scherrer Institute and the University of Fribourg) , Ascona,
Switzerland, July (1998).
S. N. Nakamura, K. Nagamine, T . Matsuzaki, K .
Ishida, N. Kawamura, S. Sakamoto, M. Iwasaki,
M. Tanase, M. Kato, K. Kurosawa, H. Sugai, I.
Watanabe, K. Kudoh, N. Takeda, and G. H. Eaton:"K.e/Ka ratio of muon to alpha sticking X-ray inmuon catalyzed dt fusion at RIKEN-RAL Muon Facility", Monte Verita Workshop on Exotic Atoms,
Molecules and Muon Catalyzed Fusion, (Paul Scherrer Institute and the University of Fribourg) , Ascona,
Switzerland, July (1998).
K. Sugawara-Tanabe: "Pseudospin-orbit interaction
and normal spin-orbit interaction", Predeal Int.
Summer School on Structure and Stability of N ucleon and Nuclear Systems, Predeal, Romania, Aug.
(1998).
A. Ozawa: "Measurement for interaction cross-sections
for carbon isotopes at relativistic energy and the halo
structure in 19C", '98 Seminar on Nuclear Physics
with Radioactive Ion Beam and High Spin Nuclear
Structure, Lanzhou, China, Sept. (1998).
K. Ishida: "Projects of high-intensity muon channels at RIKEN-RAL and KEK-MESON Facilities",
PRISM KUICR98 Workshop, (Institute for Chemical Research, Kyoto University), Uji , Sept. (1998).
Y. Mochizuki, K. Takahashi, T. Janka, W. Hillebrand,
and R. Diehl: "The long half-life of highly ionized
44Ti" , 1998 Fall Meet. of the Physical Society ofJapan, Akita, Oct. (1998).

H. Madokoro, J. Meng, M. Matsuzaki, and S. Yamaji:"Relativistic mean field description of the identicalbands and band crossing in superdeformed Eu-Gd
nuclei", 1998 Fall Meet. of the Physical Society ofJapan, Akita, Oct. (1998).
K. N agamine, T. Matsuzaki, K. Ishida, S. N.
Nakamura, Y. Matsuda, S. Sakamoto, M. Tanase, M.
Kato, K. Kurosawa, H. Sugai, K. Kudo, N. Takeda,
and G. H. Eaton: "Muon catalyzed fusion experiment for D-T system at RIKEN-RAL Muon Facility(10): Helium accumulation effect", 1998 Fall Meet.
of the Physical Society of Japan, Akita, Oct. (1998).
K. Nagamine, K. Shimomura, S. Sakamoto, and K.
Nishiyama: "Study of the energy spectrum emitted
from the nuclear-captured jl-", 1998 Fall Meet. of
the Physical Society of Japan, Akita, Oct. (1998).
K. Ishida, K. Nagamine, T. Matsuzaki, S. N.
Nakamura, N. Kawamura, Y. Matsuda, S. Sakamoto,
M. Tanase, M. Kato, K. Kurosawa, H. Sugai, K.
Kudoh, N. Takeda, and G. H. Eaton: "Muon catalyzed dt fusion research at RIKEN-RAL Muon Facility (11): Muon sticking probability", 1998 Fall
Meet. of the Physical Society of Japan, Akita, Oct.
(1998).
H. Fuke and K. Yoshimura: "Response of the BESS
scintillator for heavy ions", 1998 Fall Meet. of the
Physical Society of Japan, Akita, Oct. (1998).
K. Uchiyama, M. Sugita, and K. Furuno: "Systematic
study of B(E2; ot -+ 2t) for the Ba isotopes", 1998
Fall Meet. of the Physical Society of Japan, Akita,
Oct. (1998).
C. Kato, K. Munakata, T. Kohno, H. Miyasaka, I.
Yamagiwa, T. Goka, and H. Matsumoto: "The
pitch angle distributions of trapped particles observed with MIDORI", 1998 Fall Meet. of the Physical Society of Japan, Akita, Oct. (1998).
T. Goka, H. Matsumoto, S. Takagi, T. Kohno, andF. Makino: "Empirical radiation belt models basedon the Japanese satellites measurements", 3rd Int.
Workshop on Radiation Effects on Semiconductor
Devices for Space Application, (Japan Atomic Energy Research Institute, National Space Development Agency of Japan), Takasaki, Oct. (1998).
T. Kohno: "Heavy ion radiation in space observed
by Japanese satellite", 3rd Int. Workshop on Radiation Effects on Semiconductor Devices for Space
Application, (Japan Atomic Energy Research Institute, National Space Development Agency of Japan),
Takasaki, Oct. (1998).
Y. Mochizuki, K. Takahashi, T. Janka, W. Hillebrand,
and R. Diehl: "The long half-life of highly ioniezed 44Ti and cassiopeia A" , Nihon Tenmon Gakkai
1998nen Syuki Nenkai, Yamagata, Oct. (1998).
K. Ishida: "X-ray and neutron studies on a-sticking
in D-T jlCF", RIKEN Symp. on Muon Science'98: New Direction in Muon Catalyzed Fusion jlSR
Studies and Fundamental Muon Physics, Wako, Oct.
(1998).
249

H. Madokoro and M. Matsuzaki: "The superdeformed
bands in proton rich A=60 nuclei" , YITP Workshop
on Structure and Reaction of Unstable Nuclei, Kyoto, Nov. (1998).
Y. Mochizuki: "A microscopic model of neutron starglitches", Workshop on the Birth and Evolutionof Neutron Stars, (Tokyo University), Tokyo, Dec.
(1998).
Y. Mochizuki: ,,44Ti: Its effective half-life in young supernova remmants and abundance in Cas-A", Workshop on the Birth and Evolution of Neutron Stars,(Tokyo University), Tokyo, Dec. (1998).

3.

Atomic and solid-state physics

Y. Yamazaki: "Interaction of highly charged ionswith matter from meV to TeV", 3rd RIKEN Symp.
on Studies on Condensed Matter Physics, Atomic
Physics, Nuclear Chemistry, and Biomedical Science
using RIKEN Accelerators, Wako, Jan. (1997).
1. Shimamura: "Rich structure in atomic photoionisation cross sections", Congr. 97(The Institute ofPhysics Ann. Congr.), Leeds, UK, Mar. (1997).
T. Matsuo, T. Kohno, S. Makino, M. Sano, T.
Tonuma, H. Tawara, A. Kitagawa, and T. Murakami:"Net ionization cross sections for molecular targets
in 6 MeV /amu fully-stripped ion impact", 20th Int.
Conf. on Physics of Electronic and Atomic Collisions, Vienna, Austria, July (1997).
1. Shimamura: "Long-lived antiprotonic helium", 20thInt. Conf. on the Physics of Electronic and Atomic
Collisions, Vienna, Austria, July (1997).
1. Shimamura: "Antiprotonic atoms", 7th Asia PacificPhysics Conf., Beijing, China, Aug. (1997).
Y. Kobayashi, Y. Yoshida, K. Hayakawa, K. Yukihira,J. Nakamura, H. Haesslein, R. Sielemann, S. Nasu,
N. Inabe, Y. Watanabe, A. Yoshida, M. Kase,
A. Goto, Y. Yano, E. Yagi, and F. Ambe: "Inbeam Mossbauer spectrometers for materials science at RIKEN Accelerator Research Facility", Int.
Conf. on the Applications of the Mossbauer Effect,(ICAME97), Rio de Janeiro, Brazil, Sept. (1997).
M. Matsumoto, E. Idesawa, K. Makishima, M.
Kokubu, M. Tashiro, T. Murakami, K. Takizawa,
Y. Saito, and Team Hxd: "Develop~ent of a fine
X-ray collimator for the hard X-ray instrument onboard ASTRO-E", Nihon Tenmon Gakkai 1997nen
Syuki Nenkai, Utsunomiya, Sept. (1997).
S. Sakamoto and A. Matsushita: "Experimental result and proposal of RIKEN-RAL Muon Facility:
Elementary Particle, Nuclear and Atomic Physics",
RIKEN Symp. on Muon Science '97: Muon Condensed Matter Studies and Muon Catalyzed Fusion,
Wako, Sept. (1997).
W. Higemoto: "Experimental result and proposalof RIKEN-RAL Muon Facility: p,SR(2)", RIKEN
Symp. on Muon Science '97: Muon Condensed Mat250

ter Studies and Muon Catalyzed Fusion, Wako, Sept.
(1997).
V. Krishnamurthy: "Experimental result and proposalof RIKEN-RAL Muon Facility: p,SR(l)", RIKEN
Symp. on Muon Science '97: Muon Condensed Matter Studies and Muon Catalyzed Fusion, Wako, Sept.
(1997).
K. Nagamine: "Direct observation of electron transfer
in protein by muon", 3rd RIKEN Symp. on .Studies on Condensed Matter Physics, Atomic Physics,
Nuclear Chemistry and Biomedical Science Using
RIKEN Accelerators, Wako, Jan. (1998).
Y. Yoshida: "Materials science at the RI Beam Factory", 3rd RIKEN Symp. on Studies on Condensed
Matter Physics, Atomic Physics, Nuclear Chemistry
and Biomedical Science Using RIKEN Accelerators,
Wako, Jan. (1998).
E. Yagi: "Analysis of the state of hydrogen by the
nuclear-reaction channelling method" , Symp. on the
Suppression of the Degradation on Highly Strengthened Materials used under the Environmental Conditions, (The Iron and Steel Indtitute of Japan),Awaji, Feb. (1998).
T. Nishimura: "Elastic scattering of positrons frommethane molecules", 53rd Ann. Meet. of PhysicalSociety of Japan, Funabashi, Mar. (1998).
Y. Kobayashi, Y. Yoshida, K. Hayakawa, A. Yoshida,
Y. Watanabe, Y. Yano, and F. Ambe: ,, 57 Fe
Mossbauer spectroscopy using 5 7 Mn nuclei by aprojectile-fragment reaction", 53rd Ann. Meet. ofPhysical Society of Japan, Funabashi, Mar. (1998).
Y. Yoshida, Y. Kobayashi, K. Hayakawa, K. Yukihira,F. Ambe, and S. Nasu: "The dynamic behaviorof Fe atoms in solid Ar depending on both thespecimen-thickness and the measuring-time", 53rd
Ann. Meet. of Physical Society of Japan, Funabashi,
Mar. (1998).
M. Kitajima, Y. Nakai, Y. Kanai, Y. Yamazaki, and
Y. Itoh: "Present status of the differential cross section measurement experiment of multi-electron capture in the low energy ion-atom collision" , 53rd Ann.
Meet. of Physical Society of Japan, Funabashi, Mar.
(1998).
Y. Takabayashi, T. Ito, T. Azuma, K. Komaki, Y.
Yamazaki, M. Torikoshi, A. Kitagawa, E. Takada,and T. Murakami: "Okorokov effect with relativistic heavy ions (3)", 53rd Ann. Meet. of PhysicalSociety of Japan, Funabashi, Mar. (1998).
S. Kaneko, H. Sakata, Y. Ono, Y. Taguchi, N. Nishida,
and T. Kambara: "STS observations of columnar
defects in layered materials", 53rd Ann. Meet. ofPhysical Society of Japan, Narashino, Mar. (1998).
N. Kuroda, N. Ishikawa, S. Okayasu, A. Iwase, H.
Ikeda, R. Yoshizaki, and T. Kambara: "AC susceptibility measurements in Bi-based oxide superconductors irradiated with GeV heavy ions", 53rd Ann.
Meet. of Physical Society of Japan, Narashino, Mar.
(1998).

T. Kamei, T. Takayanagi, K. Wakiya, Y. Nakai, Y.
Kanai, and T. Kambara: "Measurement of angular
distribution in collision of N5+ -Ar by Toroidal Spectrometer", 53rd Ann. Meet. of Physical Society ofJapan, Narashino, Mar. (1998).
S. Uramoto, 1. Krajcar-Bronic, and M. Kimura:"Charge transfer process of 0+ +H collision nearthreshold", 53rd Ann. Meet. of Physical Societyof Japan, Narashino, Mar. (1998).
K. Kuroki, Y. Turuta, N. o kabayashi , T. Azuma, Y.
Yamazaki, and K. Komaki: "Proton spattering byslow multiply charged ions", 53rd Ann. Meet. ofPhysical Society of Japan, Narashino, Mar. (1998).
T. Kambara: "Atomic collision study with recoil ion
momentum spectroscopy", Int. Symp. on Atomic
Process of Highly Charged Heavy Ions and Cluster
Ions, (Himeji Institute of Technology), Himeji, Mar.
(1998).
Y. Yamazaki: "Potential sputtering of hydrogen atoms
on a surfaces with slow highly charged ions", Int.
Symp. on Atomic Process of Highly Charged Heavy
Ions and Cluster Ions, (Himeji Institute of Technology), Himeji, Mar. (1998).
E. Yagi: "Studies of impurities in metals by achannelling method utilizing a nuclear reaction",
Int. Workshop on JHF Science (JHF98), (KEK),
Tsuku ba, Mar. (1998).
J. Nakamura, K. Asai, N. Yamada, Y. Noro, H.
Kitazawa, T. Okada, Y. Kobayashi, and F. Ambe:"The studies on magnetics materials by means of
121Sb and 61 Ni Mossbauer spectroscopy", RIKEN
Symp. on RI as Probes and Tracers '98, Wako, Mar.
(1998).
Y. Yoshida, K. Hayakawa, K. Yukihira, Y. Kobayashi,
F. Ambe, and S. Nasu: "Direct observation of thejump processes of 57Fe atoms in solids by in-beem
Mossbauer spectroscopy", RIKEN Symp. on RI as
Probes and Tracers '98, Wako, Mar. (1998).
Y. Kobayashi, A. Yoshida, Y. Watanabe, N. Aoi,
J. Nakamura, Y. Yano, F. Ambe, Y. Yoshida,
K. Hayakawa, and K. Yukihira: "57Fe in-beam
Mossbauer spectroscopy using 57Mn nuclei by aprojectile-fragmentation", RIKEN Symp. on RI as
Probes and Tracers '98, Wako, Mar. (1998).
E. Yagi: "Feasibility of channelling experiments utilizing a short-lived radioactive ion beam" , KEK Seminar, Tanashi, Apr. (1998).
A. Iwase, N. Ishikawa, Y. Chimi, K. Tsuru, O.
Michikami, and T. Kambara: "High energy heavy
ion irradiation damage in oxide superconductor
EuBa2Cu30y", 4th Int. Symp. on Swift Heavy Ionsin Matter(SHIM98), Berlin, Germany, May (1998).
N. Kuroda, N. Ishikawa, S. Okayasu, A. Iwase, H.
Ikeda, R. Yoshizaki, and T. Kambara: "Pinning andVortex dynamics in Bi-based oxide superconductors
irradiated with heavy-ions", 4th Int. Symp. on Swift
Heavy Ions in Matter(SHIM98), Berlin, Germany,
May (1998).

T. Nishimura: "Interest in positron-molecule collision", The Society for Atomic Collision Research,
The Meet. for Youth, '98 Summer School', Oarai,
July (1998).
A. Igarashi, 1. Shimamura, and T. Tonuma: "Hyperfine transitions in low-energy p + PIL scattering: A
hyperspherical close-coupling study", Monte Verita
Workshop on Exotic Atoms, Molecules and Muon
Catalyzed Fusion, Ascona, Switzerland, July (1998).
Y. Takabayashi, T. Ito, K. Komaki, Y. Yamazaki, T.
Azuma, H. Tawara, M. Torikoshi, A. Kitagawa, E.
Takada, and T. Murakami: "Convoy electron prodution with relativistic heavy ions", 23rd Ann. Meet.
of the Society for Atomic Collision Research, Yokohama, Aug. (1998).
Y. Yamazaki: "Historical review and perspective of
atomic collision research from atomic physics andparticle-beam physics views", 23rd Ann. Meet. of
the Society for Atomic Collision Research, Yokohama, Aug. (1998).
B. Nystrom: "Noise reduction of CCD-images used
in VUV-spectroscopy: A statistical approach", 23rd
Ann. Meet. of the Society for Atomic Collision Research, Yokohama, Aug. (1998).
T. Azuma, T. Ito, Y. Takabayashi, K. Komaki, Y.
Yamazaki, M. Sano, M. Torikoshi, A. Kitagawa, E.
Takada, and T. Murakami: "Observation of Okorokov effects with relativistic heavy ions", 23rd Ann.
Meet. of the Society for Atomic Collision Research,
Yokohama, Aug. (1998).
T. Ito, K. Komaki, Y. Yamazaki, T. Azuma,
M. Torikoshi, A. Kitagawa, E. Takada, and T.
Murakami: "Energy loss measurements of chargestate-frozen Ar 17 + ions", 23rd Ann. Meet. of theSociety for Atomic Collision Research, Yokohama,Aug. (1998).
B. Nystrom, T. Kambara, Y. Kanai, and Y. Nakai:"Double electron capture vs. target excitation inslow He 2+ + He collisions", 23rd Ann. Meet. of theSociety for Atomic Collision Research, Yokohama,Aug. (1998).
S. Uramoto, H. Sato, and 1. Shimamura: "Twoelectron excited states of the hydrogen molecule",
23rd Ann. Meet. of the Society for Atomic Collision
Research, Yokohama, Aug. (1998).
T. Ichioka, H. Higaki, H. Matsushima, Y. Yamazaki,
K. Komaki, M. Hori, K. Yamashita, N. Oshima, A.
Mouri, and K. Kuroki: "Developments of charged
particle trap of ultra slow antiproton experiments" ,23rd Ann. Meet. of the Society for Atomic Collision
Research, Yokohama, Aug. (1998).
T. Nishimura: "Polarization effects on the vibrationally elastic scattering of positrons from methane
molecules", 23rd Ann. Meet. of the Society for
Atomic Collision Research, Yokohama, Aug. (1998).
E. Yagi , T. Sasahara, T. Joh , M. Hacke, T. Urai,
T. Sasamoto, T . Watanabe, and S. T. Nakagawa:"State of Xe atoms implanted in Fe" , 1998 Fall251

(123rd) Meet. of Japan Institute of Metals, Matsuyama, Sept. (1998).
H. Yamada, T. Hasegawa, N. Komuro, T. Maruyama,
K. Akimoto, and E. Vagi: "Characterization of undoped ZnSeTe by RBS, PIXE/ channelling measurements" , 1998 Fall Meet. of Japan Society of Applied
Physics, Higashihiroshima, Sept. (1998).
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" , 1998 Fall Meet. of the Physical Societyof Japan , Nishiharacho, Sept. (1998).
Y. Takabayashi, T. Ito, T. Azuma, K. Komaki, Y.
Yamazaki, H. Tawara, M. Torikoshi, A. Kitagawa,E. Takada, and T. Murakami: "Convoy electron production with relativistic heavy ions", 1998 Fall Meet.
of the Physical Society of Japan, Nishiharacho, Sept.
(1998).
T. Ichioka, M. Hori, K . Yamashita, H. Matsushima, H.
Higaki, N . Oshima, Y. Yamazaki, K. Komaki, and
R. Hayano: "Experiments with electrons confined ina penning trap", 1998 Fall Meet . of the PhysicalSociety of Japan, Ginowan, Sept. (1998).
Y. Morishita, S. Ninomiya, Y. Yamazaki, K . Kuroki,
K. Komaki, H. Masuda, and M. Sekiguchi: "Visible
light emission from slow highly charged ions transmitted through Ni microcapillary", 1998 Fall Meet.
of the Physical Society of Japan, Nishiharacho, Sept.
(1998) .
M. Kitajima, Y. Nakai, Y. Kanai, Y. Yamazaki, and
Y. Itoh: "Doubly differential cross section measurements of multi-electron capture in the low energy
ion-atom collision" , 1998 Fall Meet. of the PhysicalSociety of J apan, Nishiharacho, Sept. (1998).
T. Kamei, K. Ogura, T. Takayanagi, K. Wakiya, Y.
Nakai, and Y. Kanai: "Angular dependence of theemitted electron spectrum in the collision of N5+
and Ar", 1998 Fall Meet. of the Physical Societyof Japan , Nishiharacho, Sept. (1998).
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", 1998 Fall Meet. of the Physical Society ofJapan, Nishiharacho, Sept. (1998).
T. Ito , Y . Takabayashi, K . Komaki, Y. Yamazaki, T.
Azuma, M. Torikoshi, A. Kitagawa, E. Takada, T.
Murakami, and S. Datz: "Okorokov effect with relativistic heavy ions (4)", 1998 Fall Meet. of the Physical Society of Japan , Nishiharacho, Sept. (1998).
T. Azuma, T. Ito, Y. Takabayashi, K. Komaki , Y.
Yamazaki, M. Sano, M. Torikoshi, A. Kitagawa, E.
Takada, and T. Murakami: "Observation of Okorokov effect with relativistic heavy ion beams", 1998
Fall Meet. of the Physical Society of Japan, Nishiharacho, Sept. (1998).
Y. Yamazaki: "Production of ultra slow antiprotons
and atomic physics/atomic collisions", 1998 Fall
252

Meet. of the Physical Society of Japan , Nishiharacho, Sept. (1998).
E. Vagi: "State of inert gas atoms and hydrogenin metals as observed by the channelling method",1998 Fall Meet. Phys. Soc . Jpn., Lattice DefectSymp. on Recent Progress in Experimental Studies
on Point Defects and the Related Problems, Naha,
Sept . (1998).
T. Maruyama, T. Hasegawa, N. Komuro, H. Yamada,
W. Ohtsuka, K. Akimoto, Y. Kitajima, E. Vagi, andK. Maeda: "Analysis of Cl-doped ZnSeTe using EXAFS , RBS and PIXE" , 2nd Int. Symp. on Blue
Laser and Light Emitting Diodes(2nd ISBLLED),
Kisarazu, Sept. (1998).
E. Vagi: "Analysis of the state of hydrogen dissolved
in metals by means of a nuclear-reaction-channelling
method", 136th Fall Meet. of The Iron and SteelInstitute of Japan, Symp. on Studies on the Effectof Hydrogen on the Embrittlement of, Matsuyama,
Sept. (1998).
N. Ishikawa, Y. Chimi , N. Kuroda, A. Iwase, and T.
Kambara: "Ion-velocity effects on defect production
in metals and high-Tc superconductors irradiatedwith swift heavy ions" ,9th Int. Conf. on the Physics
of Highly Charged Ions (HCI-98), Bensheim, Germany, Sept. (1998).
K. Ishii, S. Kawae, T. Nakano, K. Ando, H. Oyama,
and T. Kambara: "Beam-foil spectra of highly
charged Neon ion in visible region", 9th Int. Conf.
on the Physics of Highly Charged Ions (HCI-98) ,Bensheim, Germany, Sept. (1998).
Y. Zou, R. Hutton, S. Huldt, 1. Martinson, K. Ando, T.
Kambara, B. Nystrom, and Y. Awaya: "limitationsof the beam-foil method in lifetime measurements",
9th Int. Conf. on the Physics of Highly Charged
Ions (HCI-98), Bensheim, Germany, Sept. (1998).
R. Hutton, Y. Zou, S. Huldt, 1. Martinson, K.
Ando, T. Kambara, B. Nystrom, H. Oyama, and Y.
Awaya: "A CCD detector system for beam-foil spectroscopy" , 9th Int. Conf. on the Physics of Highly
Charged Ions (HCI-98), Bensheim, Germany, Sept .
(1998).
T. Kamei, K. Ogura, K. Wakiya, T. Takayanagi, Y.
Kanai, and Y. Nakai: "Angular distribution of Auger
electrons from doubly-excited N3+ produced by 50
keV N5+ -Ar collisions", 9th Int. Conf. on the
Physics of Highly Charged Ions (HCI-98), Bensheim,
Germany, Sept. (1998).
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" , 9th Int. Conf. on the Physics ofHighly Charged Ions (HCI-98), Bensheim, Germany,
Sept. (1998).
K . T6kesi , Y. Awaya, T. Kambara, Y . Kanai, andB. Sulik: "Double K-shell vacancy production in
N 7 + + Ti collisions" ,9th Int. Conf. on the Physics ofHighly Charged Ions (HCI-98), Bensheim , Germany,Sept. (1998).
N. 'Okabayashi, ' K: Kuroki, Y. Turuta, T. Azuma, K.
Komaki, and Y. Yamazaki: "Two dimensional velocity distribution of potential sputtered hydrogen ionswith slow highly charged ions" ,9th Int. Conf. on'the
Physics of H.ighly Charged Ions (HCI-98), Bensheim,
Germany, Sept. (1998).
K. Kuroki, T. Takahira, Y. Turuta, ,N. o kabayashi ,T. Azuma, K. Komaki, and Y. Yamazaki: "Charge
state dependence of proton sputtering from solid surfaces with slow highly charged ions", 9th Int. Conf.
on the Physics of Highly Charged Ions (HCI-98),
Bensheim, Germany, Sept. (1998).
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", 9th Int. Conf.
on the Physics of Highly Charged Ions (HCI-98) ,Bensheim, Germany, Sept. (1998).
Y. Takabayashi, T. Ito, T. Azuma, K. Komaki, Y.
Yamazaki, H. Tawara, M. Torikoshi, A. Kitagawa,E . Takada, and T. Murakami: "Convoy electron production in 390 MeV l u Ar 17 + ion collisions with thinfoils", 9th Int. Conf. on the Physics of Highly
Charged Ions (HCI-98), Bensheim, Germany, Sept.
(1998).
T. Ito, T . Azuma, K . Komaki, Y. Yamazaki,
M. Torikoshi, A. Kitagawa, E. Takada, and T.
Murakami: "Direct observation of energy loss ofcharge-frozen hydrogen-like Ar ions" ,9th Int . Conf.
on the Physics of Highly Charged Ions (HCI-98),
Bensheim, Germany, Sept. (1998).
I. Shimamura: "Atomic physics of muon-catalyzed
fusion", Symp. on Supercomputing, Collision Processes and Applications, Belfast, UK, Sept. (1998) .
Y. Yamazaki: "Atomic physics and related fields",
1998 Fall Meet. of the Physical Society of Japan,
Akita, Oct. (1998).
Y. Yamazaki, N. Okabayashi, K. Kuroki, and K.
Komaki: "Angular distribution of potential sputtered hydrogen ions with slow highly charged ions",
2nd Japan-Russia Symp. on Interactions of Fast
Charged Particles with Solids, (Nagoya University
and Atomic Energy Society of Japan) , Nagoya, Oct.
(1998) .
I. Shimamura: "Extraordinarily long-lived hadronic
helium", Int. Meet. on Frontiers of Physics(IMFP98), Kuala Lumpur, Malaysia, Oct. (1998).
Y. Yamazaki: "Aiming at antimatter production:
Developments of slow antiproton beams andatomic physics·atomic collisions", Rikkyo Daigaku
Rigakubu Butsuri Danwakai, Tokyo, Nov. (1998).
K. Ishida, K. Nagamine, and T. Matsuzaki: "Topics
on muonic atoms and molecules and muon catalyzed
fusion" , ISAS 1998 Workshop on Atomic and Molecular Processes in Space' Atomic and Molecular Processes Involving Exotic Particles', (The Institute ofSpace and Astronautical Science), Sagamihara, Dec .

(1998).
Y. Yamazaki: "Developments 'of new ,fields with ultra slow highly charged ions and antiprotons" , Nihon
Butsuri Gakkai Kyushu-shibu Reikai , (The 'PhysicalSociety of Japan), Miyazaki, Dec. (1998).
I. Shimamura: "Atomic physics of exotic atoms",
Uchu-Kagaku Kenkyuusyo Uchu Kuukan Genshi Bunshi Katei Kenkyuukai, (The Institute ' ofSpace and Astronautical Science), Sagamihara, ' Dec.
(1998).
'
A. Igarashi, I. Shimamura, and N. Toshima: "Atomic
collisions involving positrons and muons", UchuKagaku Kenkyuusyo Uchu Kuukan Genshi Bunshi
Katei Kenkyuukai, (The Institute of Space and Astronautical Science), Sagamihara, Dec. (1998). 'Y. Yamazaki:"Production of slow antiprotons
and atomic collisions: Ionization and anti protonic
atom formation", Uchu-Kagaku Kenkyuusyo Uchu
Kuukan Genshi Bunshi Katei Kenkyuukai, (The Institute of Space and Astronautical Science), Sagamihara, Dec. (1998).
T. Nishimura: "Elastic scattering of positron fromatoms and molecules", Uchu-Kagaku Kenkyuusyo
Uchu Kuukan Genshi Bunshi Katei Kenkyuukai,(The Instit ute of Space and Astronautical Science),
Sagamihara, Dec. (1998).

4.

Radiochemistry, radiation chemistry, and radiat ion biology

Z. Du, I. Narumi, S. Kitayama, and H. Watanabe:"Molecular cloning of the Deinococcus mdiodurans
pprA gene involved in DNA repair", Ann. Meet.
of Japan Society for Bioscience, Biotechnology, andAgrochemistry, Tokyo, Apr. (1997).
I. Narumi, Z. Du , S. Kitayama, and H. Watanabe: "A
new DNA repair gene, pprA of Deinococcus radiodurans is functional in E. col-t, Ann. Meet. of Japan Society for Bioscience, Biotechnology, and Agrochemistry, Tokyo, Apr. (1997).
S. Ambe, H. Maeda, S. Enomoto, T . Ozaki, and F.
Ambe: "Multitracer study on permeation of rareearth elements through a supported liquid membrane", 4th Int. Conf. on Methods and Applications of Radioanalytical Chemistry, (American Nuclear Society), Hawaii, USA, Apr. (1997) .
H. Wang, S. Ambe, N. Takematsu, and F. Ambe:"Multitracer study of acid rain effect on adsorption of trace elements on soils", 4th Int. Conf. on
Methods and Applications of Radioanalytical Chemistry, (American Nuclear Society), Hawaii, USA,
Apr. (1997).
I. Narumi, K. Cherdchu, S. Kitayama, and H.
Watanabe: "uvrA gene of radioresistant bacterium,
Deinococcus radiodurans and mutation site in two radiosensitive mutants" , 70th Ann. Meet. of Japanese
Biochemical Society, Kanazawa, Sept. (1997).
253

W. Hong, J. Kaneko, and N. Ito: "Extremely fast decay
component of UV luminescence from 2 Me V / amu ion
irradiated alumina" ,9th Int. Conf. on Radiation Effects in Insulators-9 (REI-9), Knoxville, USA, Sept.
(1997).
F. Ambe: "Multitracer-A tracer technique developed by using RIKEN Ring Cyclotron", Asia-PacificSymp. on Radiochemistry '97 (APSORC '97), (Kumamoto University), Kumamoto, Oct. (1997).
Y. Kobayashi, Y. Yoshida, K. Hayakawa, K. Yukihira,J. Nakamura, H. Haesslein, R. Sielemann, S. Nasu,
N. Inabe, Y. Watanabe, A. Yoshida, M. Kase,
A. Goto, Y. Yano, E. Yagi, and F. Ambe: "Inbeam Mossbauer spectroscopy in materials science at
RIKEN Accelerator Research Facility", Asia-PacificSymp. on Radiochemistry '97 (APSORC'97), (Kumamoto University), Kumamoto, Oct. (1997).
S. Gouthu, T. Arie, and 1. Yamaguchi: "Selectionof plants for phytoremediation of soil contaminatedwith radionuclides and the impact of some parameters on plant uptake", Int. Meet. on Influenceof Climatic Characteristics upon Behavior of Radioactive Elements, (Institute for Environmental Sciences), Rokkashomura, Oct. (1997).
S. Kitayama, 1. Narumi, and H. Watanabe: "RecR mutation of D. radiodurans" , 40th Ann. Meet. of Japan
Radiation Research Society, Kyoto, Nov. (1997).
K. Funayama, M. Kikuchi, S. Kitayama, and H.
Watanabe: "Analysis of the contriol region of genes
in a radioresistant bacterium, Deinococcus radiodurans" , 40th Ann. Meet. of Japan Radiation Research Society, Kyoto, Nov. (1997).
1. Narumi, o. Kou, S. Kitayama, and H. Watanabe:"Induction of a new DNA repair gene, pprA of
Deinococcus radiodurans" , 40th Ann. Meet. ofJapan Radiation Research Society, Kyoto, Nov.
(1997).
M. Kikuchi, 1. N arumi, S. Kitayama, and H.
Watanabe: "New style of genome formation estimated by physical mapping of genomes in radioresistant bacterium Deinococcus mdiodurans" , 40th Ann.
Meet. of Japan Radiation Research Society, Kyoto ,Nov. (1997).
K. Satoh, 1. Narumi, M. Kikuchi, T. Yanagisawa, S.
Kitayama, and H. Watanabe: "Molecular analysis of
the cinA -recA operon of Deinococcus radiodumns",
20th Ann. Meet. of Japanese Society of Molecular
Biology, Kyoto, Dec. (1997) .
1. Narumi, S. Kitayama, and H. Watanabe: "Analysis
of DNA-binding ability of Deinococcus radiodurans
pprA gene product", 20th Ann. Meet. of JapaneseSociety of Molecular Biology, Kyoto, Dec. (1997).
S. Kitayama, 1. Narumi, M. Kikuchi, T. Funayama,and H. Watanabe: "DNA recombination and Repair
in Deinococcus radiodurans" , 20th Ann. Meet. ofJapanese Society of Molecular Biology, Kyoto, Dec.
(1997) .
F. Ambe: "Nuclear Chemistry in the last decade '88254'98", 3rd RIKEN Symp. on Studies on Condensed
Matter Physics, Atomic Physics, Nuclear Chemistry
and Biomedical Science Using RIKEN Accelerators ,Wako, Jan. (1998).
S. Yoshida: "An effective mutation method for plants
using heavy-ion beams" , 3rd RIKEN Symp. on Studies on Condensed Matter Physics, Atomic Physics,
Nuclear Chemistry and Biomedical Science Using
RIKEN Accelerators, Wako, Jan. (1998).
S. Enomoto, R. Hirunuma, J. Chou, S. Ambe, and F.
Ambe: "Transfers of various elements from the placenta to the fetus of pregnant rat" , 118th Ann. Meet.
of the Pharmaceutical Society of Japan, Kyoto, Mar.
(1998).
F. Ambe, S. Enomoto, R. Hirunuma, and S. Ambe:"U ptake of various trace elements in HeLa cell",
118th Ann. Meet. of the Pharmaceutical Societyof Japan, Kyoto, Mar. (1998).
R. Hirunuma, S. Enomoto, S. Ambe, F. Ambe, and
K. Endo: "Dynamics of various trace elements in
Se-deficient rats", 118th Ann. Meet. of the Pharmaceutical Society of Japan, Kyoto, Mar. (1998) .
K. Matsumoto, N. Sotogaku, S. Ueda, K. Endo, S.
Enomoto, S. Ambe, and F. Ambe: "Affinity of biotrace elements to cell componet, in vivo study using
multitracer", 118th Ann. Meet. of the Pharmaceutical Society of Japan, Kyoto, Mar. (1998).
N. Sotogaku, K. Matsumoto, K. Endo, R. Hirunuma,
S. Enomoto, S. Ambe, and F. Ambe: "The influence of citrate acid on the complex formation ofserum protein with various trace elements", 118th
Ann. Meet. of the Pharmaceutical Society of Japan,
Kyoto, Mar. (1998).
M. Miki, Y. Mizutani , K. Okamoto, Y. Izumi, T.
Kozawa, K. Ushida, Y. Yoshida, and S. Tagawa:"Study on the behavior of geminate ion pair in alkane
by using picosecond pulse radiolysis: Electron scavenging effect", 74th Natl. Meet. of the Chemical
Society of Japan, Kyoto, Mar. (1998).
S. Enomoto: "Biological application of the multitracer
technique", RIKEN Symp. on RI as Probes andTracers '98, Wako , Mar. (1998).
S. Ambe: "Applications studies on environmental science by using the multitracer technique", RIKEN
Symp. on RI as Probes and Tracers '98, Wako, Mar.
(1998).
z. Chang: "A study of metal-ion bindings to humic
acid by multitracer" , RIKEN Symp. on RI as Probes
and Tracers '98, Wako, Mar. (1998).
Y. Einaga: "The 57Fe Mossbauer studies of lightinduced magnetic properties of cobolt-iron cyano
complexes", RIKEN Symp. on RI as Probes andTracers '98, Wako , Mar. (1998).
R. Amano: "Behavior of trace elements in the brain",
RIKEN Symp. on RI as Probes and Tracers '98,
Wako, Mar. (1998).
Y. Takahashi, Y. Minai , Y. Makide, S. Ambe, and F.
Ambe: "Multitracer study for chemical speciation

of various elements on the environment: Focusing on
their complexation with humic acid" , RIKEN Symp.
on RI as Probes and Tracers '98, Wako, Mar. (1998).
R. Hirunuma, S. Enomoto, K. Endo, S. Ambe, and F.
Ambe: "Behavior of trace elements in Se-deficientrats", RIKEN Symp. on RI as Probes and Tracers'98, Wako, Mar. (1998).
T. Ozaki, Y. Makide, S. Enomoto, S. Ambe, F. Ambe,and Y. Minai: "Study on the uptake of rare earth
elements by Dryopteris erythrosom", RIKEN Symp.
on RI as Probes and Tracers '98, Wako , Mar. (1998).
N. Sotogaku, K. Matsumoto, K. Endo, R. Hirunuma,
S. Enomoto, S. Ambe, and F. Ambe: "Binding properties of various metals to serum proteins", RIKEN
Symp. on RI as Probes and Tracers '98, Wako, Mar.
(1998) .
S. Gouthu, T. Arie, and 1. Yamaguchi: "Role of plants
in bioremediation of soils and the influence of soiltypes and soil-microbes", RIKEN Symp. on RI as
Probes and Tracers '98, Wako, Mar. (1998).
F. L. Pratt, S. Ohira, and K. Nagamine: "Electrontransfer in cytochrome-c observed by J-L+ spin relaxation", 7th RIKEN-RAL PAC, Wako , Mar. (1998).
H. Iwai; T. Abe, S. Yoshida, and S. Satoh: "Production and morphological analysis of the mutants
correlated with intercellular attachment in haploid
Nicotiana plumbaginifolia" , 1998 Ann. Meet. of theJapanise Society of Plant Physiologists, Sapporo,
May (1998).
R. Hirunuma, S. Enomoto, T. Ozaki, S. Ambe, and
F. Ambe: "Transfers of trace elements from the placenta to the fetus of pregnant rat using the multitracer technique", 9th Symp. on Roles of Metals
in Biological Reactions , Biology and Medicine, (The
Pharmaceutical Society of Japan), Kumamoto , May(1998).
R. Hirunuma, K. Endo, S. Enomoto, S. Ambe, and
F. Ambe: "Study of behavior of trace elements in
Se-deficient rats", 8th Ann. Meet. of the Japan
Society for Biomedical Research on Trace Elements,
Sapporo, June (1998).
F. Yatagai, Y. Kagawa, A. Gordon , N. Fukunishi, T.
Shimazu , K. Tatsumi , A. Fujie , and F. Hanaoka:"Mutational events after heavy-ion exposure", 32nd
Scientific Assembly of COSPAR, Nagoya, July
(1998).
Y. Furusawa, M. Saitou, K. Fukutsu, F. Yatagai, M.
Vazquez, T. C. Yang, and T. Kanai: "Different cellular effects of heavy ions at the same LET" , 32nd Scientific Assembly of COSPAR, Nagoya, July (1998).
K . Suzuki, T. Abe , Y. Katsumoto, Y. Fukui, S. Tuda,
S. Yoshida, and T. Hisazumi: "Isolation of flower
color changing mutants using heavy-ion beams irradiation", 16th Ann . Meet. and Symp. of JapaneseSociety for Plant Cell and Molecular Biology, Sendai,
July (1998).
C. H. Bae, T. Abe, T. Matsuyama, T. Nakano, and S.
Yoshida: "Production of tobacco mutants inducedwith heavy-ion beams irradiation", 16th Ann. Meet.
and Symp. of Japanese Society for Plant Cell andMolecular Biology,' Sendai , July (1998).
T. Abe, S. Yoshida, N. Fukunishi, N. Inabe, M. Kase,
A. Goto, and Y. Yano: "An effective mutation
method of plants using heavy-ion beams", 16th Ann.
Meet. and Symp. of Japanese Society for Plant Celland Molecular Biology, Sendai, July (1998).
F. Yatagai, A. Gordon, S. Morimoto, N. Fukunishi, M.
Honma, T. Sofuni, and F. Hanaoka: "HPRT mutation induced by heavy-ion irradiation, the effect ofp53", Gordon Reseach Conf. on DNA Alteration~
in Transformed Cells, New Hampshire, USA, Aug.
(1998).
K. Ushida: "New phorochemistry and new radiation chemistry: Beyond Synchrotron Radiation" ,9th
Riron Kagaku Symp., Seto, Aug. (1998).
K. Ishioka, K. Ushida, S. Hishita, K. Nakamura, andM. Kitajima: "Phonon dynamics in ion-irradiatedbismuth", 1998 Fall Meet. of the Physical Society ofJapan, Naha, Sept. (1998).
S. Ambe, T. Ozaki, T. Shinonaga, H. Wang, and S.
Enomoto: "Factors affecting the absorption of traceelements by plants" , 42nd Symp. on Radiochemistry,
Sendai, Sept. (1998).
Z. Chang, S. Ambe, N. Takematsu, K. Takahashi, Y.
Takahashi, and F. Ambe: "Multitracer study on
the binding of trace elements to humic acid", 42ndSymp. on Radiochemistry, Sendai, Sept. (1998).
F. Yatagai, T. Saito, A. Takahashi, and T. Ohnishi:"Mutation induction in the rpsl gene on an E. coli-B.
subtillis shuttle vector by space flight on MIR" , 49th
IAF Cong., (The International Astronautical Federation, The International Academy of Astronautics,
and The International Institute of Space Law) , Melbourne, Australia, Sept. (1998).
1. Fujiwara, Y. !toh, R. Iwata, F. Saito, and A. Goto:,,18F intense spot positron source for spin polarized positron beam", 8th Int. Workshop on Slow
Positron Beam Techniques for Solid and Surfaces,(Union of Cape Town), Cape Town , South Africa,
Sept. (1998).
1. Fujiwara, Y. !toh, R. Iwata, T. Nozaki, and A.
Goto: "Preparation of an intense positron source byelectro-deposition of 18F on a graphite-electrode",
OECD /NEA Workshop on Ion and Slow Positron
Beam Utilization, Lisbon, Portugal, Sept. (1998).
S. Yoshida and T. Abe: "Plant biotechnology using
heavy-ion beams" , 1998 Fall Meet. of the PhysicalSociety of Japan , Akita, Oct. (1998).
C. H. Bae, T. Abe , T. Matsuyama, T. Nakano, K.
Miyoshi, and S. Yoshida: "Mutants induction using
heavy-ion beams irradiation in ovules and cultured
anthers of tobacco plants" ,94th Congr. of the Breeding Society of Japan , Iwate, Oct. (1998).
T . Matsuyama, T. Abe, Y. Takahashi, C. H. Bae, T.
Nakano, T. Asami , and S. Yoshida: "RLGS analysis in plant genome: Preliminary studies for mutant
255

analysis", 94th Congr. of the Breeding Society ofJapan, Iwate, Oct. (1998).
M. Miki, Y. Mizutani, K. Okamoto, Y. Izumi, T.
Kozawa, K. Ushida, Y. Yoshida, and S. Tagawa:"Study on the behavior of geminate ion pair in alkane
by using picosecond pulse radiolysis : Measurement
by using white light continuum", 41st Symp. on Radiation Chemistry, Kobe, Oct. (1998) .
K. Ushida, K. Ishioka, S. Hishita, K. Nakamura, andM. Kitajima: "Coherent phonon spectroscopy on
ion-beam irradiated solids", 41st Symp. on Radiation Chemistry, Kobe, Oct. (1998).
S. Morimoto, A. Gordon, N. Fukunishi, M. Honma, T.
Sofuni, F. Hanaoka, and F. Yatagai: "HPRT mutation induction by heavy-ion irradiation: The effect ofmutant p53 gene", 27th Ann. Meet. of the Japan
Environmental Mutagen Research Society, Osaka,Nov. (1998).
T. Arie, S. Gouthu, S. Ambe, and 1. Yamaguchi:"Plant uptake of radionuclides and rhizosphere factors", A Nuclear Cross-Over Research Symp.: New
Approaches in Environmental Radioactivity, (Promotion Committee on Nuclear Cross-Over Research,
Japan and Specialist Committee on Assessment andReduction of Radiation Risks, Japan), Wako, Nov.
(1998).
M. Yoshimasu, T. Abe, S. Yoshida, T. Inoue, F. Ling,
and T. Shibata: "Biological effects of heavy-ion
beam on budding yeast cells", 20th Ann. Meet. ofJapanese Society of Molecular Biology, Yokohama,Dec. (1998).
P. Mehnati, F. Yatagai, F. Hanaoka, T. Tsuzuki, and
H. Sasaki: "Judgement on 'Hit or Non-hit' by timelapse observations on CHO cells", 41st Ann. Meet.
of the Japan Radiation Research Society, Nagasaki,
Dec. (1998).
T. Kato, H. Tauchi, K. Komatsu, K. Ishizaki, F.
Yatagai, and M. S. Sasaki: "Mutation spectrum forhuman tumor cell deficient in mismatch repair gene
hMSH3", 41st Ann. Meet. of the Japan Radiation
Research Society, Nagasaki, Dec. (1998).
M. Saitou, Y. Furusawa, T. Kanai, M. E. Vazguez, T.
C. Yang, F. Yatagai, and F. Soga: "RBE of lethal
effects on V79 cells by high-LET heavy-ions", 41stAnn. Meet. of the Japan Radiation Research Society, Nagasaki, Dec. (1998).
T. Kanai, N. Matsufuji, Y. Futami, and F. Yatagai:"Radiation dosimetry and LET estimation for biological irradiation with heavy charged particles",
41st Ann. Meet. of the Japan Radiation ResearchSociety, Nagasaki, Dec. (1998).
S. Morimoto, A. Gordon, N. Fukunishi, M. Honma, T.

256

Sofuni, F. Hanaoka, and F. Yatagai: "Analysis of
HPRT mutation induced by heavy-ion irradiation",
41st Ann. Meet. of the Japan Radiation ResearchSociety, Osaka, Dec. (1998).

5.

Material analysis

A. Tonomura, K. Maeda, H. Hamanaka, and K.
Hasegawa: "Chemical shift measurements using
high-resolution PIXE system with position-sensitive
crystal spectrometer", 45th Spring Meet., 1998, The
Japan Society of Applied Physics and Related Societies, Hachioji, Mar. (1998).
H. Yoshiki, K. Maeda, A. Tonomura, T. Tsuruda,
and H. Higuchi: "PIXE Analysis of trace elementin feathers", 4th Asian Symp. on Academic Activities for Waste Management, (Asian Association of
Academic Activities for Waste Management), Seoul,
Korea, Aug. (1998).
T. Kobayashi, G. Dorenbos, C. F. McConville, M.
Iwaki, and M. Aono: "Depth profiling and lattice
location of Sb atoms in a Si/Sb( 8-doped) lSi structure formed by solid phase epitaxy using a MECAICISS", 59h Autumn Meet., 1998, The Japan
Society of Applied Physics, Higashihiroshima, Sept.
(1998) .
K. Maeda, K. Hasegawa, A. Tonomura, H. Hamanaka,
and M. Maeda: "Chemical state analysis by in-air
high-resolution PIXE(I) : Kf3 spectra", 16th PIXE
Symp., Ha.chimantai, Oct. (1998).
A. Tonomura, T. Hasegawa, H. Hamanaka, K.
Hasegawa, and K. Maeda: "Chemical state analysis by in-air high-resolution PIXE(2): KQ spectra",16th PIXE Symp., Hachimantai, Oct. (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",
16th PIXE Symp., Hachimantai, Oct. (1998).
H. Yoshiki, K. Maeda, A. Tonomura, and H. Higuchi:"PIXE analysis of lead in Jungle Crow's feather",
16th PIXE Symp., Hachimantai, Oct. (1998).
T. Kobayashi, T. Sakurai, T. Matsuo, H. Matsuda,
M. Iwaki, and M. Aono: "Medium-energy coaxial impact-collision ion scattering spectrometer",Symp. on Charged Particle Optics, (132nd Committee, Japan Society for the Promotion of Science),
Tsukuba, Oct. (1998).
J. Kawai, K. Hayashi, T. Yamamoto, M. Yamaguchi,
A. Nisawa, K. Okuda, and K. Maeda: "EXEFS of Al
in TiAI" , 34th Meet. for X-Ray Chemical Analysis
Japan, Sendai, Nov. (1998).

IX. LIST OF SYMPOSIA(Jan.-Dec. 1998)
1) RIKEN Symp. on Studies on Condensed Matter Physics, Atomic Physics, Nuclear Chemistry, and Biomedical Science Using RIKEN Accelerators
26 Jan., Wako, RIKEN, Nuclear Chemistry Lab.
2) RIKEN Symp. on Nuclear Chemistry of Heavy Elements at RIKEN RI-Beam Factory
27-28 Jan., Wako, RIKEN, Nuclear Chemistry Lab.
3) RIKEN Symp. on Dynamics in Hot Nuclei
13-14 Mar., Wako, RIKEN, Cyclotoron Lab.
4) RIKEN Symp. on RI as Probes and Tracers '98
17 Mar., Wako, RIKEN, Nuclear Chemistry Lab.
5) Int. Technical Advisory Committee Meet. on the Sector Magnets of RIKEN Superconducting Ring Cyclotron(SRC)
11-13 May, Wako, RIKEN, RI Beam Factory Project Office6) RIBF Workshop on Effective Interaction and Unstable Nuclei
14 Sept., Wako, RIKEN, Cyclotoron Lab.
7) RIKEN Symp. on Muon Science '98, New Direction in Muon Catalyzed Fusion and IlSR Studies andFundamental Muon Physics
7- 8 Oct., Wako, RIKEN, Muon Science Lab.
8) RIBF Workshop on Structure of Unstable Nuclei
16-18 Nov., Wako, RIKEN, Cyclotron Lab.
9) RIKEN Symp. on The Theory of Atomic and Molecular Processes (VI)19 Nov., Wako, RIKEN, Atomic Physics Lab.
10) RIKEN Symp., A Nuclear Cross-Over Research Symposium: New Approaches in Environmental Radioactivity
26- 27 Nov., Wako, RIKEN, Microbial Toxicology Lab.
11) RIKEN Symp. on Space Charge Dominated Beam Physics for Heavy Ion Fusion
10-12 Dec., Wako, RIKEN, RI Beam Factory Project Office12) Symp. on Present Status and Future of the RIKEN-RAL Muon Facility Project
14 Dec., Wako, RIKEN, Muon Science Lab.

257

x. LIST OF SEMINARS(Jan.-Dec. 1998)
Radiation Lab., Cyclotron Lab., andLinear Accelerator Lab.

1) R. Suda, Tokyo Metropolitan University (Tokyo),
KEK B-factory BELLE Group (Ibaraki), 24 Feb.
"The development of low-refractive-index silica
Aerogel Cerenkov Counter (ACC) "2) A. Kohama, RIKEN (Saitama), 9 Mar.
"Nuclear transparency in a relativistic quark
model"
3) Y. M. Zhao, RIKEN (Saitama), 23 Mar.
"Regional regularities of low-lying excitations in
nuclei"4) H. Geissel, GSI (Germany), 25 Mar.
"Precision experiments with relativistic heavy
ions at the FRS-ESR facilities"5) K. Suemmerer, GSI (Germany), 26 Mar.
"Recent results from Ar-40 fragmentation at 1000
MeV /nucleon studied at GSI"
6) N. van Do, National Center for Natural Scienceand Technology (Vietnam), 30 Mar.
"Some aspects on the exploitation of small accelerators in Vietnam"7) G. Kalinka, Institute of Nuclear Research of the
Hungarian Academy of Sciences (Hungary), 28Mar.
"Development of high performance CsI(TI) scintillator + Si pin photo diode charged particle detectors for the EUROBALL"
8) N. Pietralla, University of Koeln (Germany), 6
May"Low-lying collective dipole modes and isovector
excitations in the valence shell of heavy nuclei"
9) H. Madokoro, RIKEN (Saitama), 18 May"Relativistic mean field description of nuclear collective rotation"10) Xu Shuwei, IMP (CHINA), 19 May"Decay properties of neutron-deficient nuclei andnew nuclides near the proton-drip line"
11) E. A. Cherepanov, Flerov Laboratory of Nuclear
Reactions, Joint Institute for Nuclear Research(Russia), 22 May"The role of the quasi-fission in the reactions used
for the synthesis of superheavy elements"
25812) G. 1. Kosenko, Flerov Laboratory of Nuclear Reactions, Joint Institute for Nuclear Research (Russia), 22 May"Use of the combined dynamical evaporation approach to the calculations of the characteristics offission of excited nuclei"13) T. Tanimori, Department of Physics, Tokyo Institute of Technology (Tokyo), 22 May"The new gas PSD applicable to high count rate"14) B. R. Barrett, Department of Physics, Universityof Arizona (USA), 26 May"Large-Basis No-Core Shell-Model calculations
for light nuclei"
15) T . Kifune, Institute for Cosmic Ray Research,
University of Tokyo (Tokyo), 16 June
"Superhigh energy gamma ray astronomy by theground observation"16) N. Ohnishi, Graduate School of Arts and Sciences, University of Tokyo (Tokyo), 29 June
"Pairing correlation studied in generator coordinate method"17) A. Ansari, Institute of Physics, Bhubaneswar (India), 27 July
"Calculation of nuclear level densities incorporating corrections for thermal and quantum fluctuations"18) T. Nakatsukasa, University of Manchester (UK),12 Aug.
"Selfconsistent determination of collective coordinates in nuclear collective motion"19) C. Samanta, Saha Institute of Nuclear Physics(India), 7 Sept.
"6Li projectile breakup reaction at 0.1 A GeV"
20) A. Krasznahorkay, Institute of Nuclear Research(Hungary) , 8 Sept.
"Super- and Hyperdeformed states in the Actinide
Region"21) K. Hara, Technische Universihit of Miinchen(Germany), 16 Sept.
"How the Projected Shell Model (PSM) works"
22) M. Tanaka, Kobe Tokiwa College (Kobe), 21
Sept.
"Production of polarized 3He beam and its application"23) M. Schaedel, GSI (Germany), 28 Sept.
"Nuclear reaction paths into the region of superheavy elements and prospects of heavy element

research with radioactive beams"24) M. !inuma, Advanced Sciences of Matter, Hiroshima University (Hiroshima) , 8 Oct.
' ''Dynamic nuclear polarization in the hightemperature low-magnetic-field condition for polarized proton target"25) H. Kamada, Ruhr University (Germany), 14 Oct.
"The proton-deutron scattering and the threebody effect"26) M. N. Harakeh , KVI Groningen University (TheN ether lands), 24 Nov.
"Recent results from AGOR"
27) G. M. Jin, Institute of Modern Physics, Chinese
Academy of Science (China), 30 Nov.
"The progress of physics research in IMP"
28) G. M. Jin, Institute of Modern Physics, Chinese
Academy of Science (China), 2 Dec.
"Study on the properties of hot nuclei in IMP"
29) R. Seki, California State University, Kellogg Radiation Laboratory (USA) , 8 Dec.
"Model-independent determination of matter distributions of neutron-rich nuclei"

Atomic Physics Lab.
1) H. Shibata, RCNST, University of Tokyo(Ibaraki), 30 Jan.
"Production, acceleration, and detection of
charged fine particles"2) B. H. Gilbody, Queen's University (UK), 10 Feb.
"State-selective charge transfer collisions involving slow multiply charged ions"
3) P. C. Stancil, Oak Ridge National Laboratory(USA), 11 Mar.
"Low-energy atomic collisions in astrophysics"4) T. Kitamori, University of Tokyo (Tokyo) , 13
Mar.
"Photothermal spectroscopy and ultimate measurements - Single molecule detection in liquids
and femtosecond time resolved measurement- "5) N. Watanabe, Hokkaido University (Hokkaido),
13 Mar.
"Formation of H2 molecules on the amorphous water ice"6) M. Stockli, Kansas State University (USA), 19
Mar.
"New experiments and developments with the

KSU-EBIS"
7) P. H. Mokler, GSI (Germany), 26 Mar.
"The two-photon decay in heavy He-like ions"8) H. Geissel, GSI (Germany), 27 Mar.
"Slowing down of relativistic heavy ions and new
applications"
9) T. Goto, Nagoya Institute of Technology(Nagoya)., 27 Mar.
"Absolute measurements of Auger electrons"10) S. Datz, Oak Ridge National Laboratory (USA),
17 Apr.
"Atomic collision physics at ultra-relativisic energies"
11) K. Kageyama, Saitama University (Saitama), 1
May"Basis of non-destructive inspections by ultrasonic waves"
12) M. Lamoureux (University of Paris) and M. Niimura RIKEN (Saitama), 8 May"ECRIS oscillatory regime discussed in relation
with their performances"
13) N. Kabachnik, Moscow State University (Russia),
19 May"Multiple ionization of atoms and molecules by
fast ion impact"
14) H. M. Shimizu, Cosmic Radiation Laboratory,
RIKEN (Saitama), 21 May"Development of superconducting tunnel junctions"
15) B. Sulik, ATOMKI (Hungary), 5 June
"Experimental separation of two- and three- bodyeffects in the ionization of Li by the impact of fast,
highly charged ions: Analogies between photonand ion-impact ionization"16) T. Ishikawa, SPring-8, RIKEN (Saitama) , 19
June"Study of X-ray optics at SPring-8"17) H. Dezso, RMKI (Hungary), 26 June
"Brief review of anticyclotron"18) H. Tsuchida, Nara Women's University (Nara),
28 July"Mechanisms of ionization and fragmentation in
fast ion-C 6o collisions"19) T. Azuma, University Tsukuba (Ibaraki), 18 Aug.
"Correlation between radiative electron capture259,

into continuum and convoy electron"20) A. Dalgarno, Harvard-Smithsonian Center for Astrophysics (USA), 6 Oct.
"Ultra-cold collisions of atoms and molecules"
21) J . S. Cohen, Los Alamos National Laboratory(USA), 9 Oct.
"Isotope effects on capture of exotic particles"22) M. Inokuti, Argonne National Laboratory (USA),
10 Dec.
"Electron degradation in gaseous media"
23) K. Ueda, Toyota Technological Institute (Nagoya),
17 Dec.
"Behavior of hydrogen on metallic and semiconductor surface studied by electron -excited ion detachment"24) Chii-Dong Lin, Kansas State University (USA) ,18 Dec.
"Visualization of correlations in triply excitedstates of atoms"25) Chii-Dong Lin, Kansas State University (USA),
18 Dec.
"Weakly-bound atomic and molecular systems"

RI Beam Factory1) T. Saitoh, RCNP, Osaka University (Osaka), 8
Jan.
"Present Status of the RCNP Ring Cyclotron"
2) F. Caspers, CERN (Switzerland), 21 Jan.
"Topics around stochastic cooling"3) N. Takahashi, Okayama University (Okayama), 5
Feb.
"Overview of calculation of electromagnetic force
in three dimensional analysis on magnetic fields
and calculation of electromagnetic forces of theSuperconducting Ring Cyclotron"
4) G. Wei, Institute of Modern Physics , Chinese
Academy of Science (China), 9 Feb.
"About stochastic cooling"5) E. Syresin, JINR(Russia),l1 Mar.
"Theory and experimental investigations of EBISin the reflection operation mode"
6) V. Mirnov, JINR(Russia), 14 May"Plasma investigation in PPL"

260

7) S. Pal, VECC(India),15 May"Cryogenic system for K-500 Superconducting
Cyclotron at VECC"
8) M. Lamoureux, University of Pierre and Marie
Curie (France), 4 June
"Characteristics and role of the hot electrons in
the ECR ion sources"
9) P. Sigg, PSI(Switzerland), 28 July
"Recent experimence with high beam power operation and improvements of the PSI RF-System"10) V. Shevtsov, JINR(Russia), 26 Aug.
"N umerical simulation of charged particle dynamics in transportation"11) A. Denker, Hahn Meitner Institute(Germany), 22
Oct.
"Inverstigation of objets d'Art with PIXE using
68 MeV protons"
12) U. Trinks, University of Miinchen(Germany) , 27
Oct.
"Superconducting cyclotron development in Munich"13) E. Baron, GANIL(France), 29 Oct.
"Status of the GANIL operation and of the SPIRAL project"
14) E. Baron, GANIL(France), 4 Nov.
"Heavy ions traversing foils: Charge state distribution, energy spread, emittance growth and foil
lifetime"
15) G. Ryckewaert, Louvain-la-Neuve(Belgium), 9
Dec.
"Status of the cyclotrons at the University in
Louvain-Ia-Neuve: Uses for research and development"

Muon Science Lab.
1) G. zu Putlitz, University Heidelberg (Germany),
14 Dec.
"Report of the external review committe on
RIKEN-RAL Muon Facility Project"

Microbial Toxicology Lab.
1) E. E. T. Smolders, Leuven University (Belgium),
16 Dec.
"Transfer of radionuclides and related elementsfrom soil to plant and their mobility in soil"

XI. LIST OF PERSONNELRIKEN Accelerator Research Facility

TANIHATA Isao
YANO Yasushige~:J:HI ~:t
lff tc ~(Facility Director)(Vice Facility Director)*-=

Linac Division
IKEZAWA Eiji ?ill rR ~KOHARA Shigeo IJ'\ JJj{ ~ ::k=KASE Masayuki

11D iii J§ z * 1

Ring Cyclotron Division
FUJITA Jiro ~ EE
fm
IKEGAMI Kumio 7tt!LfL '::: ~KAGEYAMA Tadashi ~ ill iE
KASE Masayuki 11D mi J§ Z
KUBO Toshiyuki A 1* ~ ¥NAKAGAWA Takahide q:t]ll 1f.
OKUNO Hiroki J1lff J1: ~t

GOTO Akira fi ~ ~*1
INABE Naohito flB:ill ro1 A
KAMIGAITO Osamu -.t:rn9~{~ ­KOHARA Shigeo IJ'\}jj( ~ :t
NAGASE Makoto -ft mi IDit
OGIWARA Kiyoshi M( JJj{ 1t
YOKOYAMA Ichiro tl ill - fm

Experimental Support Division
I CHIHARA Takashi
JJj{¥
KAN AI Yasuyuki 1ii if f* Z
MATSUZAKI Teiichiro ;f~ ijf1~mfl~
WATANABE Yasushi Vi jl

KAMBARA Tadashi t$ JJj{ iE * 1
KUMAGAI Hidekazu 1f~ ~*0
MORITA Kosuke ~ EE rtff 1}
YATAGAI Fumio ~EEJtJt:t

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Radioisotope Facilities Division
KOBAYASHI Yoshio IJ'\;ft ~ ~Radiation Protection Group
FUJITA Shin ~ EE *jf*l
NAKAJIMA Shunji r:p ~ ~¥=Administration Division
NAKAMURA Toshiko q:t ft L-=f
NUMATA Shigeo rt5 EE If ~cSteering Committee
GOTO Akira fi JJi ~ISHIHARA Masayasu D)Jj( iE ~KASE Masayuki 110 iii J§ Z
MATSUOKA Masaru ;f~ Wi] )}9}
NAG AMINE Kanetada 71<. ~ ~ ,~,SAWA Hiroshi if
7i:.
TANIHATA Isao ~ iffi ~ ::k=YAMAZAKI Yasunori ill ~~~1*3
YATAGAI Fumio ~H3J!Jt::k=**1 Group Leader, *2 Manager,

ITO Sachiko -fft ~ :ff. -=f
OGIWARA Kiyoshi M()Jj(

NISHIGUCHI Fumiyoshi

1t~ 0 Jt H~*2

HANAOKA Fumio Th Wi] Jt 1$
KAMBARA Tadashi t$}jj( iE
KATSUMATA Koichi )}9} X *1L MATSUZAKI Teiichiro ;f~ijH~mfl~
NISHIGUCHI Fumiyoshi ~ 0 Jt H*
TAKAMI Michio 1Jj J? ~ ~YAGI Eiichi )\YAN 0 Yasushige
lff tc I
YOSHIDA Shigeo E H3 If ~**-* -*3 Chairperson

261

RI Beam Factory Project Office
Head
YANO Yasushige-':k ff 1;: £Members
IKEGAMI Kurnio ntLtn =:!15
KAMIGAITO Osarnu J::tlIj}fl~­
OHNISHI Jun-ichi
1!9 ~ SAKAMOTO Naruhiko ~px rJ
WAKASUGI Masanori ~ if~ J§ ~* *INABE Naohito fIB ill rEJ A
KUBO Toshiyuki j.... 1* fi& ¥OKUNO Hiroki J!: ff Jt. tn
TANABE Toshiya EB ill fit:. i:!1

Visiting Members and Postdoctoral Fellows
AMANO Ryohei 7( lij- .& If (Fac. Med., Kanazawa Univ.)
ARAKAWA Kazuo JiE JII *0 ~ (J AERI, Takasaki Rad. Chern. Res. Estab.)
BANDYOPACHYAY Arup
(Variable Energy Cycl. Cen., India)
BATYGIN Yuri
CHATTOPADHYAY Subrata(Variable Energy Cycl. Cen., India)
CHIBA Toshiya T ~ flJ ~CHIBA Yoshiaki T ~ ~t lJ)j (Tokyo Electr. Tech. Serv.)
DINH DANG Nguyen
ENDO Kazutoyo J!: ~ *0 1£ (Showa ColI. Pharrn. Sci.)
ENOMOTO Shuichi tI~
FUJISAWA Takashi Hi rR ~ iit (Denki Kogyo Co., Ltd.)FUJISHIMA Shiro ~ ~ ~ ~~ (I.H.I.)
FUKUDA Mitsuhiro ti H3 7t 7i (JAERI, Takasaki Rad. Chern. Res. Estab.)
FUKUNISHI Nobuhisa ti 1!9 ~ r#J
HEMMI Masatake ~ ~ 1&
HIMENO Seiichiro ~1l'fIDiX:-e~ (Kitasato Univ.)
HIRUNUMA Rieko !I!I¥BflJiI-fHONMA Toshihiro
Fa' ~ It. (N.I.R.S.)
IN AMURA Takashi T. fiB tt
IWAMA Motonori ~ ra, £ ~)l1 (Shizuoka Univ.)
KATAYAMA Takeshi h LlJ
RJ (Cen. Nucl. Study, Grad. Sch., Sci. Univ. Tokyo)
KAWAGUCHI Takeo JII 0~(Mitsubishi Elec. Co., Ltd.)KIM Jong-Won
MATSUMOTO Ken-ichiro tl*~-~~ (Showa ColI. Pharm. Sci.)
MINAI Yoshitaka ~ ~ 1t -2f:. (Musashi Univ.)it (N ara Medical Univ.)
MINAMI Takeshi 1¥J
MIRONOV Vladmir(J.I.N.R., Dubna, Russia)
MITSUOMOTO Toshinori
1~ ~(Surnitorno Heavy Ind., Ltd.)it fit:.
MIYAZAWA Yoshitoshi '8
MORIKAWA Tetsuya ~]l1 Ji i:!1
MOT ONAGA Shyoushichi 5C 71<. BH -t
NAGAFUCHI Teruyasu 71<. i~U ~f. Eft (Toshiba Corp.)
NIIMURA Masanobu $Jf tt IE 1-g; (Sch. Sci. Eng., Waseda Univ.)
NODA Kouji lij- EB *fI: RJ (N.I.R.S.)
OHKAWA Tomohiro
JII 9§I 7i (Mitsubishi Heavy Ind., Ltd.)OHTOMO Kiyotaka -}( 17:. it ~~ (Surnitorno Heavy Ind., Ltd.)OHYAMA Takuya
LlJ 11) i:!1 (Shizuoka Univ.)
OKAMOTO Youichi Wi]
i$ (Showa ColI. Pharm. Sci.)
OKAMURA Masahiro [RiJ tt J§ 7i
OKUMURA Susumu J!: tt ~ (JAERI, Takasaki Rad. Chem. Res. Estab.)
SAITO Furninori 1f Ai Y. f~
SEKINE Hirotaka ~ tK ~t. ~~SIDORIN Anatoly(J.I.N.R., Dubna, Russia)
SUGn Kazuo if~ #- -!:t (Osaka Vacuum, Ltd.)SUZUKI Hiroyuki jfJ~t. iT(Chiba Univ.)

* m:

*

-*

m:
m:

m:

*i* *

*
* *
*

262

TAKAHASHI Masaaki ~ tl iE BH (Osaka Prefect. Univ.)
TAKANAKA Masao ~ ftp i& it
TAKEUCHI Suehiro ¥r P'J
rt. (JAERI, Tokai Res. Estab.)
TANAKA Yasushi H3 J:j:l f~;=E- (Kyokuto Boeki Kaisha, Ltd.)TOMIMASU Takio ~±~~%~ (Free Electrons Laser Res. Inst.)
TOMIN AKA Toshiharu ~ J:j:l flJ i5 (Hitachi, Ltd.)TOMIZAWA Masato ~ if iE A (KEK)
1$ (Cen. for Nucl. Study, Grad. Sch., Sci. Univ. Tokyo)
WATANABE Shin-ichi ioc
WATANABE lkuo
fl~ ~(Toshiba Corp.)
WU Dezhong(lnst. Modern Phys., Academia Sinica, China)
XIA Jia-Wen Ji fi X (Inst. Modern Phys., Academia Sinica, China)
YANAGA Makoto *- ,]<. W&. A (Shizuoka Univ.)
YANAGIYA Takahiro t~D:e:- ~i 11:. (Kitasato Univ.)
YOKOUCHI Shigeru ;fft P'J tt (Osaka Vacuum, Ltd.)YOKOYAMA Ichiro ;fft ill - ~~YONEDA Akira
H3 ~ (Houshin Corp.)
YOSHIDA Tsutomu E H3 ~ (Shizuoka Univ.)
YOSHIDA Yutaka E H3 ~ (Shizuoka lnst. Sci. Tech.)*roc:ill:ill*

Cosmic Radiation Laboratory
Members
KATO Hiroshi tm Ji. t.f
YOSHIDA Atsumasa E EE ~ iE

KOHNO Tsuyoshi

iPJ ~

~

Visiting Members and Postdoctoral Fellows
BADONO Shinro .~ »& ji ~ (Mitsubishi Elec. Corp.)}l:K (NASDA)
GOKA Tateo Ii
HASEBE Nobuyuki *:e:-~B1~1T (Waseda Univ.)
KASHIWAGI Toshisuke ;ffi
flJ 11- (Fac. Eng., Kanagawa Univ.)
KATO Chihiro DD Ji. --T ~ (Fac. Sci., Shinshu Univ.)
KIMOTO Yugo
fit:g. (NASDA)
KOBAYASHI Motohiro Ij, if* ~ 11:. (Mitsubishi Elec. Corp.)
Bff IJ-.. (NASDA)
MATSUMOTO Haruhisa t1
MUNAKATA Kazuoki
it - ~ (Fac. Sci., Shinshu Univ.)
MURAKAMI Hiroyuki tt L 115 Z (Fac. Sci., Rikkyo Univ.)
NAGATA Katsuaki 71<. EE Mf ijl] (Fac. Eng., Tamagawa Univ.)
NAKAMOTO Atsushi J:j:l
7¥ (Fac. Sci., Rikkyo Univ.)
TAKASHIMA Takeshi ~ ~ 1il! (Fac. Sci., Nagoya Univ.)
USHIO Youji i.f:iJ:t~?$ ~ (Mitsubishi Elec. Eng. Corp.)
YAMAGIWA Iwao LlJ ifPi fl£ (Tobu High School)
YANAGIMACHI Tomoki 19P IBJ ~JJ tBf (Fac. Sci., Rikkyo Univ.)

*

**

*

* *
*

Trainees
HOSHIDA Takashi £ EB ";=E- (Grad. Sch. Fac. Sci., Nagoya Univ.)
MIYASAKA Hiromasa '8 ~ 115- iE (Grad. Sch. Sci. Eng., Saitama Univ.)

Cyclotron Laboratory

Head
YANO Yasushige-!k ~ 17: .mMembers
FU JIMAKI Masaki Ji. ~ iE ~t
FUJITA Shin Ji. H3 *JT
IKEZAWA Eiji iIh iR ~==FUJITA Jiro Ji. EEe~GOTO Akira f~ Ji. 'f;
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ABURAYA Takashi im ~AKIYOSHI Hiromichi lk 15 § 7E
ARIGA Takehiro ~ jt ~ tf (Fac. Sci. , Saitama Univ.)(NASDA)
BABA Shinji .~ j~ 1§(KEK)
BAN Shuichi f-t Y§ BANDYOPACHYAY Arup
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BANDYOPACHYAY Tapas(Variable Energy Cycl. Cen., India)
BANERJEE Vaishali(Variable Energy Cycl. Cen., India)
BHATTACHAYA Sankar(Variable Energy Cycl. Cen., India)
BIRI Sandor(ATOMKI, Hungary)
CHAKRABARTI Alok (Variable Energy Cycl. Cen., India)
CHEVTSOV Uladmir (J.I.N.R. , Dubna, Russia)
DATE Schin ffr it 1$ (JASRI)
DINH DANG Nguyen(Fac. Sci., Saitama Univ.)
EJIRI Hiroyasu rI JJL~(Fac. Sci. , Osaka Univ.)
EN'YO Hideto }[ ij. ~ A (Fac. Sci., Kyoto Univ.)
FUJIOKA Manabu ~ ITt] ~ (Cycl. Radioisot. Cen. , Tohoku Univ.)
FUJITA Yoshitaka ~ EB 1* 11- (Fac. Sci. , Osaka Univ.)
FUJIWARA Ichiro ~ JJj( - e~ (Dept. Economy, Otemon Gakuin)
FUJIWARA Mamoru ~ JJj( ~ (RCNP, Osaka Univ.)
FURUNO Kohei rS ti ~ ~ (Tandem Accel. Cen. , Univ. Tsukuba)
FURUSE Kaoru rS liji ~ (NASDA)
Je. EJt Z (N.I.R.S.)
FUTAMI Yasuyuki
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GOKA Tateo Ii
GRUBER Bruno(Tech. Univ. Clausthal, Germany)
GU Wei(Inst. Modern Phys. , Academia Sinica, China)
HAMA Hiroyuki ~ Jt ¥(I.M.S.)
HARADA Toru JJj( EB ~~ (Sapporo Gakuin Univ.)(NASDA)HASHIMOTO Miwa tit /.$: ~HASHIMOTO Osamu tit /.$: 15 (Fac. Sci., Tohoku Univ.)
HATANAKA Kichiji 'l:HI $ 15 15 (RCNP, Osaka Univ.)
HATSUKAWA Yuichi 1JJ)lI:Iift (JAERI, Tokai Res. Estab.)
HATTORI Toshiyuki m~:g:~ 1~ ¥(Res. Lab. Nucl. React., T.I.T.)
HAYANO Ryugo !f. ff ij~ Ii (Fac. Sci. , Univ. Tokyo)
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HIGUCHI Tatsuro tim 0 it e~ (NASDA)
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HORIBATA Takatoshi #ill"!lffii 11- 1~ (Fac. Eng. , Aomori Univ.)
HORIGUCHI Takayoshi #ill 0 ~i'& (Fac. Sci. , Hiroshima Univ.)
HORIUCHI Hisashi ~ I*J 7n! (Fac. Sci., Kyoto Univ.)
HOSONO Kazuhiko {f.Hl ff~(Dept. Eng. , Sci., Himeji Inst. Tech.)HUGIWARA Ichiro Ji JJj( - e~ (Dept. Economy, Otemon Gakuin)
HYODO Toshio ~ ~J[ 1~:5J5 (Grad. Sch. Arts Sci. , Univ. Tokyo)
IDESAWA Masanori CB ii 1£ f.e (Univ. Electro-Commun.)
IGARASHI Toshio Ii +i\.fi&:lift (NASDA)

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IKEDA Kiyomi 7th 83~(Fac. Sci. , Niigata Univ.)
IKEDA Nobuo 7th 83 1$:K (Fac. Sci., Kyushu Univ.)
IKEZOE Hiroshi 7th i~ tf (JAERI, Tokai Res. Estab.)
IMAI Kenichi ~ #- ~ (Fac. Sci., Kyoto Univ.)
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IMAMURA Mineo ~ t1"
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ISHIDA Satoru E 83 'I'BISHIZUKA Takeo E f~~
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ITO Yasuo 1¥ ~ $ ~ (Atomic Energy Res. Cen., Univ. Tokyo)
ITOH Hiroshi 1¥ ~ Jl (KEK)ITOH Kazuya #J- Hi ~o -tl1
ITOH Yoshiko 1¥
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IWAMOTO Akira E
IWASA Naohito :E ~ rr! {=IWASHITA Yoshihisa :E ~ 7i J\ (Inst. Chern. Res., Kyoto Univ.)
IWATA Ren :E 83 ~t (Cycl. Radioisot. Cen. , Tohoku Univ.)~IJ.
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IZUMOTO Toshiaki jjt
JEONG S. C.
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KAMIMURA Masayasu L t1" 1E
KANAZAWA Mitsutaka ~ iR 7t ~i (N.I.R.S)
KANEKO J unichi ~ -=t- ~ (J AERI, Tokai Res. Estab.)
KATAYAMA Ichiro h III - e~ (KEK)
KATO Kiyoshi~ ~ 7i(Fac. Sci., Hokkaido Univ.)
KATO Shohei~ ~ if(Fac. Sci. , Osaka Univ.)
KATORI Kenji illlX ~(Fac. Sci., Osaka Univ.)
KATSURAGAWA Hidetsug ff)ll 1§ Iffl~ (Fac. Sci., Toho Univ.)
KAWAZU Akira i~ if J! (Techno Riken Co., Ltd.)=tj: 1E ~KID ERA Masanori
KITAGAWA Hisashi ~t JII f#J (KEK)
KLUGE Thomas(Liptih Univ., Germany)
KOHAMA Akihisa IJ, iJ: i$ 9(:
KONDO Michiya J1I: ~ if! ill (RCNP, Osaka Univ.)
KOTAJIMA Kyuya ti83~J\~ (Fac. Eng., Tohoku Univ.)
KOYEN Ali
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KUDO Hisaaki I ~ J\ BH (Fac. Sci., Niigata Univ.)
KUMATA Masayuki ~~ 83 ~ Z (N.I.R.S.)
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KURITA Tetsurou ~ 83 13" e~ (Inst. Phys., Univ. Tsukuba)
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LEE Sang Mu
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LIU Sheng Li(Inst. Modern Phys. , Academia Sinica, China)
MADOKORO Hideki re, pJT 1§f!r (Interdisciplinary Grad. Sch. Eng. Sci., Kyushu Univ.)
MAEDA Kazuhide frI 83 ;to 1§ (Fac. Sci., Kyushu Univ.)
MATSUDA Sumio tl 83 ~:K (NASDA)
MATSUI Yoshiko tl #- 7i -=t- (Fac. Technol. , Tokyo Univ. Agric. Technol.)ill: 9: (Inst. Chern. Res., Kyoto Univ.)
MATSUKI Seishi tl~ i$(NASDA)
MATSUMOTO Akihiro 1J}
MATSUSE Takehiro tllfji)l: 115- (Fac. Textile Sci. Technol. , Shinshu Univ.)
MATSUYANAGI Kenichi 1J} t~p liJf (Fac. Sci., Kyoto Univ.)
MATSUZAKI Kazuhiro 1J} UJ~ - 115- (N ASDA)
MATUZAKI Masayuki tl UJ~ ~ Z (Fukuoka Univ. Educ.)
MENG Jie(Peking Univ., China)
MINAMISONO Tadanori r¥J iii ,'it', ~Ij (Fac. Sci. , Osaka Univ.)
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MIZUSAKI Takahiro
MORI Yoshiharu ~ ~ i8 (KEK)MUKHOPADHYAY Tapan(Variable Energy Cycl. Cen. , India)
MURAKAMI Hideoki tt L "!Ii:. ~ (Tokyo Gakugei Univ.)
MURAKAMI Tetsuya tt L :tg ill (Fac. Sci., Kyoto Univ.)
MURAYAMA Toshiyuki tt LlJ flJ ¥ (Tokyo Univ. Mercantile Marine)
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NAGAI Yasuki ,1< jf ~ ~1 (Fac. Sci., T.LT.)
NAGAI Yuki ,1< jf ill if.C (NASDA)
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NAGASHIMA Yasuyuki
NAKADA Hitoshi I:fJ 83 t
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NAKAGAWA Keiko I:fJ )11 ~ r
NAKAHARA Hiromichi I:fJ JJj( "5.l. ~ (Fac. Sci., Tokyo Metrop. Univ.)
NAKAI Ko-zi I:fJ jf 11!i(Fac. Sci. Technol., Sci. Univ. Tokyo)
NAKAMURA Hiroyuki I:fJ tt tti L(Fac. Sci., Kyushu Univ.)
NAKAMURA Ichiro I:fJ tt~~(Fac. Sci., Saitama Univ.)
NAKAMURA Takashi I:fJ tt riD Fl] (Cycl. Radioisot. Cen., Tohoku Univ.)
NAKAO Noriaki I:fJ f=§ r.re ~ (KEK)
NAKASHIMA Hiroshi I:fJ ~(JAERI, Tokai Res. Estab.)
NEMOTO Norio tN.
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NODA Akira ff 83 •NOMURA Toru ~ tt ~ (KEK)NOZAKI Tadashi ~ Iliij- iE (Kagami Memorial Lab., Mater. Sci., Waseda Univ.)
OGAWA Kengo 11',}l1 ~.g: (Dept. Eng. Sci., Himeji Inst. Technol.)f f§(NASDA)
OHIRA Hideharu~ if! ~
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OHNISHI Naoki
OHNISHI Tetsuya~ ~ ~(Fac. Sci., Univ. Tokyo)
OHTSUKI Tsutomu
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OHYA Jiro
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OKAMOTO Hiromi [1liJ(Fac. Sci., Saitama Univ.)
OKAMURA Hiroyuki [1liJ tt "5.l. L
OOTOMO Hiromitu
17:. i$ 7t (NASDA)OTA Kiyoshi -}:::. 83 iJ (Fac. Sci., Saitama Univ.)OTSUKA Takaharu~ -1f. 18(Fac. Sci. , Univ. Tokyo)
OZAWA Shuichi IJ'\ iR {~- (Coll. Sci., Rikkyo Univ.)
SAGARA Kenshi:fEl .& Jl ~ (Fac. Sci. , Kyushu Univ.)
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SAKAI Hideyuki i~ jf "!Ii:. iT (Fac. Sci., Univ. Tokyo)
SAMBATARO Michelangelo(LN.F.N. , Catania, Italy)
SATO Ken-ichi it Mi 51 (Dept. Phys., Tohoku Coll. Pharm.)(RCNP, Osaka Univ.)
SATO Kenji it Jfi ~SATO Yukio it &i ¥(N.LR.S.)SATOU Yoshiteru it &i ~SEKINE Toshiaki ~ tN. ~ ~ (JAERI, Tokai Res. Estab.)
SHARMA Sumit(Pune Univ., India)
SHENG Yeng Ching it )( Jt (Shanghai Inst. Nucl. Res., China)
SHIBATA Tokushi ~ 83 r.re .~, (KEK)
SHIKAZONO Naornoto J.I.f: III if! ~ (JAERI, Tokai Res. Estab.)BB (RCNP, Osaka Univ.)
SHIMIZU Akira iJ
SHIMOMURA Kouichiro T;ft1~ - ~~ (Mes. Sci. Lab. , KEK Brunch, Univ. Tokyo)(Fac. Eng., Kyoto Univ.)
SHIN Kazuo ~ fD
SHIN Seung Ai $ ;if'\. ~ (Rika Women's Coil., Korea)
SHINDO Hiroyuki *Jf &i 1~ L
(NASDA)SHINOZUKA Tsutornu r~:t~(Cycl. Radioisot . Cen. , Tohoku Univ.)
SHIRAI Toshiyuki El jf fii!l. L(Nucl. Sci. Res. Fac., Inst. Chern. Res. , Kyoto Univ.)

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SHUGYO Shin-ichi {~iT ~ (NASDA)§ ~ (Fac. Sci., Tokyo Metrop. Univ.)
SUEKI Keisuke
SUGAIIsao ;g # '-k (KEK)~ iii(NASDA)
SUGIMOTO Kenji ;f~
SUGIYAMA Hiroki ;f~ LlJ
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SUMIYOSHI Hiroyuki 11 E It. iT (Matsusho-Gakuen Jr. CoH.)SUZUKI Takahiro li~ tt (NASDA)SUZUKI Toshio lifij!£ 515
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SUZUKI Toshio li
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SYRES SINE Evgucni(J.I.N.R., Dubna, Russia)
TAGAYA Yu ~1JD~;ft (Fac. Sci., Univ. Tokyo)
TAGISHI Yoshihiro ill~ 7i:(Tandem Accel. Cen., Univ. Tsukuba)
TAJIMA Naoki EE ~~ ~ fit (ColI. Art Sci., Univ. Tokyo)
TAKADA Masashi ~ ill • ~ (N.I.R.S.)
TAKAHASHI Takehide ~j:!Ii:. (NASDA)
TAKEMASA Tadashi m: i8c ¥ ± (Kyoto Univ. Educ.)
TAKIGAWA Noboru ifg)ll gf. (Fac. Sci., Tohoku Univ.)~ L
TAKIZAWA Yoshiyuki ifg
TAMAGAKI Ryouzou :E:ill.&(Fac. Sci., Kyoto Univ.)(Otsuma Women's ColI.)TAN ABE Kazuko ill:ill ~D r
TANABE Kousai ill:ill 1f: ~ (Fac. Sci., Saitama Univ.)
TANAKA Jinichi EE 9=' t:(KEK)
TANAKA Kazuhiro EE 9=' *D JJl (Med. Dept., Jyuntendo Univ.)
TAN AKA Toshio EE 9=' ~ !itt
TANIKAWA Masashi ~ JII Jm?£ (Fac. Sci., Univ. Tokyo)
TOHYAMA Mitsuru :is: LlJ i~ (Kyorin Univ.)
TOMITANI Takehiro g ~ m: i~ (N.I.R.S.)TOMODA Toshiaki Iff.. ill fij!£ iiI (Fac. Eng., Aomori Univ.)
TOPREK Dragan(VINCA, Inst. Nucl. Sci., Yugoslavia)
TORIYAMA Tamotsu ,~LlJ 1* (Dept. Phys., Musashi Inst. Technol.)(NASDA)TSUBAKI Noriyuki lJ ~IJ ¥TSUKINO Akihisa J:I ~ ~ ~ (NASDA)
UCHIYAMA Koji I*J Ll.J i~ it- (Inst. Phys., Univ. Tsukuba)
UESAKA Tomohiro 1:.:t& Iff.. i$
UTSUNO Yutaka *t~~ li (Fac. Sci., Univ. Tokyo)
UTSUNOMIYA Hiroaki *t~g~hiiI (Fac. Sci., Konan Univ.)
WADA Michiharu ~D ill ji iii (KEK)
WADA Ryoichi ~D EE .& (Texas A & M Univ., USA)
WADA Takahiro ~D EE ~ 7i: (Fac. Sci., Konan Univ.)
WAKAI Masamiti ~ # lE ji (Fac. Sci., Osaka Univ.)
WAKUTA Yoshihisa ~D~EE~~ (Fac. Eng., Kyushu Univ.)
XIAO Meigin(Dept. Phys., Grad. Sch. Sci., Univ. Tokyo)
YABANA Kazuhiro ~:;ft - i~ (Fac. Sci., Niigata Univ.)
YAMANOUCHI Mikio LlJ I*J ~ fift (Inst. Phys., Univ. Tsukuba)
YAMAZAKI Hirohito LlJ Ih~ J! t: (Lab. Nucl. Sci., Tohoku Univ.)
YAMAZAKI Takashi LlJ Ih~ ~ (PCNP, Osaka Univ.)
1L 7E(NASDA)YONEMARU Mitsunori
YOSHIDA Nobuaki E E8 '§" iiI (Fac. Sci., Univ. Tokyo)
YOSHINAGA Naotaka E 71<. !WJ 1f: (Fac. Sci., Saitama Univ.)~h (NASDA)YOSHIOKA Yasuhiro E ItrrJ
YOSHIZAWA Yasukazu E i,R.
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(Fac. Sci., Kyushu Univ.)
YUAN Ping(Inst. Modern Phys., Academia Sinica, China)
ZHANG Wenzhi(Inst. Modern Phys., Academia Sinica, China)
ZHAO Yu MinZHOU Shan-Gui(Peking Univ., China)

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Trainees
AOKI Yuka W E13 W (Grad. Sch. Sci., Tohoku Univ.)
ARIGA Takehiro ~ ~ ~ tf (Fac. Sci., Saitama Univ.)
FUJISAKI Takayuki Jii!h~ Jt Z (ColI. Sci., Rikkyo Univ.)
FUJITA Tatsuru ~ EE ~ (Interdisciplinary Grad. Sch. Eng. Sci., Kyushu Univ.)
LlJ ilE fli (Dept. Phys., Grad. Sch. Sci. , Univ. Tokyo)
HARUYAMA Seigo
HASHIMOTO Satoshi ;fiJf (Dept. Phys., Grad. Sch. Sci., Univ. Tokyo)
IWASE Hiroshi :5 if.f{ Jt. (Grad. Sch. Sci., Tohoku Univ.)(Grad. Sch. Sci., Tohoku Univ.)
KIM Eunjoo 1fi:r ,~, (Grad. Sch. Sci., Tohoku Univ.)
KINOSHITA Tadashi
KUROSAWA Tadahiro ~,~, ~l(Grad. Sch. Sci., Tohoku Univ.)
NAKAJIMA Takao I:fJ 1iIJ ~::t: (Fac. Sci., Saitama Univ.)
NAKAO Makoto I:fJ ~ IDiX: (Grad. Sch. Sci., Tohoku Univ.)
NUNOMIYA Tomoya :;fp g ~ -ill. (Grad. Sch. Sci., Tohoku Univ.)
OGATA Kentaro *~JHiJf*e~ (Fac. Sci., Kyushu Univ.)
01 Makito **7J~A (Grad. Sch. Arts Sci., Univ. Tokyo)
OKAMOTO Tomoko [tGJ
~D ~(Fac. Sci. Technol., Sci. Univ. Tokyo)
OKUDA Hikaru ~ EE -:It (Fac. Sci., Kyushu Univ.)
1iIJ 7]((Grad. Univ. Adv. Studies)
OSHIMA Nagayasu
SASAKI Michiya 1tr:4*~-ill. (Grad. Sch. Sci., Tohoku Univ.)(Fac. Sci., Kyushu Univ.)
SHIGENAGA Kouichi ~ 7]( ~ SONE Hayato ~ fi ~ A (Fac. Sci. Technol., Sci. Univ. Tokyo)
SUDA Kenji
EE ~ Ifflm (Fac. Sci., Saitama Univ.)
SUZUKI Naoki ~11
ill ~ (Grad. Sch. Arts Sci., Univ. Tokyo)
TANIGUCHI Shingo ~ 0 ~ 1i (Grad. Sch. Sci., Tohoku Univ.)TANIKAWA Atsushi ~)11 ~ Ffj (Fac. Sci., Saitama Univ.)
TOKUNAGA Youji ~ 7]( i$ it (Grad. Sch. Eng., Osaka Univ.)
TSURUTA Kaoru ~ EE 1ft (Interdisciplinary Grad. Sch. Eng. Sci., Kyushu Univ.)(Fac. Sci., Toho Univ.)WAKUI Takashi
YAGITA Takanori )\*83Jt~ (Fac. Sci., Kyushu Univ.)
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YAMAMOTO Sumiko LlJ

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TANIHATA Isao ~ iffi ~ ::t:Members
KORSHENINNIKOV Alexei A.
MORIMOTO Koji ~¥ Ffj
SUMIYOSHI Kohsuke 11 E 7t 1r
YOSHIDA Koichi E 83 -:It -*Visiting Members and Postdoctoral Fellows
ADACHI Shizuko $; J!: ijJ::;- (ICFD)
AHMADY Mohammad(Western Ontario Univ., Canada)
ARATANI Michi 51E ~ ~ ~ (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)
DATAR Vivek(Bhabha Atomic Res. Cen. , India)
DAVID Dean J.
(CALTEC, USA)DEMYANOVA AHa S.
(Kurchatov Inst. Atomic Energy, Russia)
DOKE Tadayoshi ~,~, ~(Adv. Res. Inst. Sci. Eng., Waseda Univ.)
FUJIWARA Mamoru hi mt ~ (RCNP, Osaka Univ.)
FULOP Zsolt(ATOMKI , Hungary)

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TONUMA Tadao p mlE a

GEISSEL Hans
(GSI, Germany)
GOLOVKOV Mkheil S.
(Kurchatov Inst., Russia)
GONCHAROV Sergei A.
(Kurchatov Inst., Russia)
GOSWAMI Ranjana (Variable Energy Cycl. Cen. Calcutta, India)
HIRENZAKI Satoru ltJ!w~ '1'8 (Fac. Sci., Nara Women's Univ.)
HORIUCHI Hisashi #ill ~ 7M (Fac. Sci., Kyoto Univ.)
BB (JAERI, Tokai Res. Estab.)
IWAMOTO Akira -E
IZUYAMA Takeo WRLlJft~ (Fac. Sci., Toho Univ.)
KANUNGO Rituparna(Saha Inst. Nucl. Phys., Calcutta, India)
KATORI Kenji /l[ lf~ ~(Fac. Sci., Osaka Univ.)
KIKUCHI Jun ~ ttl! JII~ (Sci. Eng. Res. Lab., Waseda Univ.)
KIMURA Kikuo *ft%~a (Fac. Eng., Nagasaki Inst. Appl. Sci.)
KOBAYASHI Toshio IJ . .
1~ til(Fac. Sci., Tohoku Univ.)
KOLATA James(Notre Dame Univ., USA)KUMAR, Suresh(Bhabha Atomic Res. Cen., India)
KURATA Mizuki ~ 83 ~ Jj (JST)KUSAKA Kensuke B T ft tt
LE Hong Khiem(Inst. Phys., Natl. Cen. Sci. Technol., Vietnam)
MARUYAMA Tomoyuki 1L LlJ ~ Z (Fac. Sci., Kyoto Univ.)
MATSUTA Kensaku tl ~ ft ~ (Fac. Sci., Osaka Univ.)
MATSUYAMA Yoshitaka t~ LlJ 7i ~ (Inst. Nucl. Study, Univ. Tokyo)
MATUOKA Nobuyuki t~ ItfiJ 1$ iT (RCNP, Osaka Univ.)
MINAMISONO Tadanori i¥i III ,'ii;, ~ Ij (Fac. Sci., Osaka Univ.)
MITTING M.
(GANIL, France)~~(Fac. Sci., Univ. Tsukuba)
MIYAKE Yasuo =: 13)3
MIYAMURA Osamu '8 tt 1~ (Fac. Sci., Hiroshima Univ.)
MOCHIZUKI Keiko ~ Jj I -=f (Fac. Sci., Osaka Univ.)
MOCHIZUKI Yuko ~ Jj 1f-=f
MOMOTA Sadao 8831!~~ (Kochi Univ. Technol.)
MURAOKA Mitsuo tt ItfiJ -Jt ~ (Fac. Eng., Aomori Univ.)
NOJIRJ Yoichi If JJL i$ (Kochi Univ. Technol.)
OGAWA Kengo IJ . . JII ft 1!r (ColI. Arts. Sci., Chiba Univ.)
OGAWA Yoko IJ . . )l1 i$ -=f (Fac. Sci., Osaka Univ.)
OGLOBLIN Alexei A.
(Kurchatov. Inst., Russia)
OHNISHI Akira[91¥3 (Fac. Sci., Hokkaido Univ.)
if: BJt (Fac. Sci., Tohoku Univ.)
OHTSU Hideaki±'=¥~t(Fac. Sci., Niigata Univ.)
OHTSUBO Takashi
OJIMA Minoru IJ . . ~,~ f.t (Fac. Sci., Osaka Univ.)
OMATA Kazuo IJ . . f~ :to ~ (lnst. Nucl. Study, Univ. Tokyo)[9
ONISHI Takashi
ORYU Shinsho ~ rL 1f 1$ (Fac. Sci. Technol., Sci. Univ. Tokyo)
OYAMATSU Kazuhiro ~1 t~ :to ¥~ (Dept. Energy Eng. Sci., Nagoya Univ.)
PETRASCU Horia (Inst. Phys. Nucl. Eng., Romania)
PETRASCU Marius(Inst. Phys. Nucl. Eng., Romania)
SAGAWA Hiroyuki 1!)II ~L. ¥(Cen. Math. Sci., Aizu Univ.)
SAKAI Hideyuki i@ #iT (Fac. Sci., Univ. Tokyo)
SATO Kazuhiro 1! ni :to rt (Tokyo Fire Dept.)
SEKI Ryoichi ~ Tt: (California Univ., USA)SHERRIL B.
(Michigan State Univ., USA)SUDA Toshimi {~83 flJ ~ (Fac. Sci., Tohoku Univ.)~(RCNP, Osaka Univ.)
SUGANUMA Hideo ;g ¥t1
SUGAWARA Masahiko ;g JJj( l§ ~ (Fundam. Sci., Chiba Inst. Technol.)
SUMMERER Klaus(GSI, Germany)SUZUKI Hideyuki i~-:Jf Z (KEK)SUZUKI Takeshi iiI
ft (Fac. Sci., Niigata Univ.)
SUZUKI Tsuneo iiItg til (Fac. Sci., Kanazawa Univ.)
SUZUKI Yasuyuki jiJ'§ Z(Fac. Sci., Niigata Univ.)
TACHIBANA Takahiro t~ ~ tf (Senior High Sch., Waseda Univ.)

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TAKAHASHI Yoshiyuki ~ t£ ~ ¥(Alabama Univ., USA)
TAKAHASHI Yutaka ~ t£ :!: (Fac. Sci., Osaka Univ.)
TOKANAI Fuyuki r~ pt ~ t!t (JST)TOKI Hiroshi ± II&: t.w: (RCNP, Osaka Univ.)TORBJOEN Baeck (Stochholm Univ., Sweden)
VARGA Kalman(Inst. Nucl. Res., Hungarian Acad. Sci., Hungary)
WADA Takahiro ~[1 EE ~f 7i (Fac. Sci., Konan Univ.)
WINKLER Martin(GSI, Germany)
YAGI Hirosuke J\
i~(Fac. Sci., Univ. Tsukuba)
YORANN Alhassid(Yale Univ., USA)ZAHAR Mohamed(Dept. Phys., Notre Dame Univ., USA)* ,illTrainees
HIBINO Masaru B JtlH fl (Fac. Sci. Eng., Waseda Univ.)
KATO Tomomi DO hi ~(Fac. Sci., Niigata Univ.)(Fac. Sci. Eng., Waseda Univ.)
KATO Toshiyuki DO Ii 13t ¥KAWA Tadahisa irlJ ,~,:A (Fac. Sci., Osaka Univ.)
MINAMISONO Kei m III §(Fac. ScL, Osaka Univ.)
OKUDA Takashi ~ 83 • it- (Fac. Sci., Tohoku Univ.)
OZAKI Kiminori ~ 1lI~ /];; ~ (Fac. Sci. Eng., Waseda Univ.)
SAKAGUCHI Takao :t!i 0 • 513 (Fac. Sci. Eng., Waseda Univ.)
SASAKI Makoto ~4* ~ (Fac. Sci., Osaka Univ.)
SATO Kazunori ~ hi ~[1 ~Ij (Fac. Sci., Osaka U niv.)
SEKIGUCHI Masatugu I*l 0 ~ ffilm (Fac. Sci., Tohoku Univ.)
SHIMIZU Noritaka~Ij 1t(Fac. Sci., Univ. Tokyo)
SHIMOOKA Masaaki T ItliJ lE SJ:I (Fac. Sci., Kyoto Univ.)
TAKAHASHI Yoshiyuki ~ t£ ~ ¥(Fac. Sci. Eng., Waseda Univ.)
TAKENAKA Sunao tT 9~(Fac. Sci. Eng., Waseda Univ.)
TAKEUCHI Satoshi m:1*J ~;e: (Fac. Sci., Rikkyo Univ.)
TANAKA Motoyuki ill $ £ Z (Fac. Sci., Waseda Univ.)
TERASAWA Kazuhiro :;!j: ¥R ~[1 i$ (Adv. Res. Inst. Sci. Eng., Waseda Univ.)
TERUHI Shigeru p.~ B ~ (Fac. Sci. Eng., Waseda Univ.)
WAKASAYA Yoshiaki =t;~~~~)j (Fac. Sci. Technol., Sci. Univ. Tokyo)
WANG Haiming .£. #iJ~!; (Fac. Sci., Univ. Tokyo)
YAMAGUCHI Yoshitaka LlI 0 E8 ~ (Fac. Sci., Niigata Univ.)
YAMASHITA Masaki LiJ T ~ tM (Adv. Res. Inst. Sci. Eng., Waseda Univ.):f; (Grad. Sch., Waseda Univ.)YUZUKI Akira ;fIB

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Radiation Laboratory
Head
ISHIHARA Masayasu

E JJj{ lE ~Members
I CHIHARA Takashi!j[
SAITO Naohito
hi mI ATAKETANI Atsushi tT ~ ~YOSHIDA Atsushi E EE ~i* m]Jj(KISHIDA Takashi J¥ EE ~f
SAKURAI Hiroyoshi tM:#- t.w: _WATANABE Yasushi ill jJ Btt

Visiting Members and Postdoctoral Fellows
ABE Yasuhisa ~iiJ 1}~
0... (Yukawa Inst. Theor. Phys., Kyoto Univ.)
ADACHI Minoru . JE
jt (Fac. Sci., Tokyo lnst. Technol.)
ANDO Yoshiaki !i: Ei ~ ~ (ColI. Sci., Rikkyo Univ.)AOI Nori w:#- ~ (Dept. Phys., Grad. Sch. Sci., Univ. Tokyo)
ASAHI Koichiro Jig(Fac. Sci., Tokyo lnst. Technol.)
ASAI Masato ¥~:#- ~ A (J AERI)
AWAYA Yoko ~ ~ ~ -T (Musashino Art Univ.)

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270

BEAUMEL Didier (Div. Phys. Theor. lPN, Inst. Phys. Nucl., France)
BECK F. A.
(CRN, France)
BROGLIA R.
(Univ. Milano, Italy)
BROOKS Melynda (Los Alamos Natl. Lab., USA)CASTEN Rick(Phys. Dept., BNL, USA)
CRIST Norman(Columbia Univ., USA)DEVI Yelamanchili Durga
DOOI Makoto 1it # Jt (Inst. Phys., Univ. Tsukuba)
ENYO Hideto ~ J} fij A (Fac. Sci., Kyoto Univ.)
FLOCARD Hubert(Div. Phys. Theor. lPN, lnst. Phys. Nucl., France)
FORTIER Simone(Div. Phys. Theor. lPN, lnst. Phys. Nucl., France)
FUCHI Yoshihide i~U H· fij (KEK, Tanashi)
FUKE Hideyuki l~
5i: Z (Fac. Sci., Univ. Tokyo)
FUKUDA Mitsunori tM EE 7t!ll~ (Grad. Sch. Sci., Osaka Univ.)
FUKUDA Naoki t~ 83 ~ tM
FUKUDA Tomokazu t~ EE*0 (KEK)FURUTAKA Kazuyoshi tl ~ *1] tJt (JAERI)GELBERG Adrian (Koln Univ., Germany)
GONO Yasuyuki m ll!1: }iFf Z (Fac. Sci., Kyushu Univ.)
GOTO Yuji 1& Jif
HAMAGAKI Hideki ~ ±~ fij:ttt (Cen. Nucl. Study, Univ. Tokyo)
1f T (Lund Inst. Technol., Univ. Lund, Sweden)
HAMAMOTO IKUKO i~
HASEGAWA Takeo -R~)lIm:~ (Fac. Eng., Miyazaki Vniv.)
HATSUDA Tetsuo f}] 83 tg" §15 (Fac. Sci., Kyoto Vniv.)
HAYASHIGAKI Aratam *'T (Yukawa lnst. Theor. Phys., Kyoto Vniv.)~:ttt
HAYASHI Naoki
HEENEN Paul-Henri(Vniv. Libre Bruxelles, Belgium)
HIRAI Masaaki f # iE BJ3HOSAKA Masahito f*:toc ~~ A (KEK, Tanashi)
ICHIMURA Munetakeft
m: (Grad. Sch. Arts Sci., Vniv. Tokyo)
IDEGVCHI Eiji #::fD*ifi (Phys. Dept. Frescati, Royal lnst. Technol., Sweden)
IEKI Kazuo~ *0 ~(ColI. Sci., Rikkyo V niv.)
IMAI Kenichi ~ # ~ IMOTO Michiko #j1t T(Lab. Phys. ColI. Sci. Technol., Nihon Univ.) .
ISHII Tetsuro 15 ·# tg"~}j ( J AERI)ITAKVRA Kazunori toc ~ *0 Be (Yukawa lnst. Theor. Phys., Kyoto Vniv.)
IWASAKI Haironori :fi ~.~ "51.. ~IWASA Naohito :fi 1tc ~ 1= (Lab. Nucl. Studies, Fac. Sci., Osaka Vniv.)
IZVMI Hideaki tJj
fij BJ3(Grad. Sch. Sci., Osaka Vniv.)
JIN Genming ¥Jf fN. ~ (Inst. Modern Phys., Chinese Acad. Sci., China)
KAKI Kaori ~ m(Fac. Sci., Shizuoka Vniv.)
KAMAE Tsuneyoshi ~ iI ~ ~f (Fac. Sci., Vniv. Tokyo)
KANEKO Tomohiro ~~ tf(Fac. Sci., Univ. Tokyo)
KASAGI Jirota 3t:*ifi~~* (Lab. Nucl. Sci., Tohoku Vniv.)
KATAYAMA !chiro Jl ill - ~~ (Cen. Nucl. Study, Vniv. Tokyo)
P](Cen. Nucl. Study, Vniv. Tokyo)
KATAYAMA Takeshi Jl ill
KATO Seigo ;1]0 Mi ~ 1fr (Fac. Educ., Yamagata Vniv.)
KATORI Kenji J1'[ lIX ~(Pac. Sci., Osaka Vniv.)
KAWASHIMA Hideo JlI!&; 5i: til (KEK, Tanashi)
KIM Jong Chan
(Dept. Phys., Seoul Natl. Vniv., Korea)-KISTENEV Edouard (Phys. Dept., BNL, VSA)KITAGAWA Hisashi ~t)ll f6J (KEK)KITAO Kensuke %~ ~ ~M (Data Eng. Inc.)KODAIRA Jirou Ij, f ifi e~ (Pac. Sci., Hiroshima Vniv.)(Fac. Sci., Vniv. Tokyo)
KOHAMA Akihisa Ij, 1~ i$
KOIKE Yuji Ij, 7th fe- P] (Pac. Sci., Niigata Vniv.)
KVBONO Shigeru ~1:*ff 7f (Cen. Nucl. Study, Vniv. Tokyo)
KVMANO Shunzo ~~ ff 1~ = (Pac. Sci. Eng., Saga Vniv.)

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271

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KUNIHIRO Teiji ~"5t. 'I:~
(Ryukoku U niv.)
KURITA Kazuyoshi ~ 83 ~D ftf
KUSAKARI Hideshige ~ ~IJ 1f ~ (Fac. Educ., Chiba Univ.)
LEE Sang Mu
tel 1J.. (lnst. Phys., Univ. Tsukuba)
LI Zhihong
it 7R (China lnst. Atom. Energy, China)
LIU Guanhua ~U nt ii: (lnst. Modern Phys., Chinese Acad. Sci., China)
LUCCIO Alfredo
LIU Zhong(lnst. Modern Phys., Chinese Acad. Sci., China)
LUKIANOV Serguei(Flerov Lab. Nucl. React., Joint lnst. Nucl. Res., Russia)
MAEDA Kazushige lW 83 ~D 1J.. (Grad. Sch. Sci., Tohoku Univ.)
MAO Yajun(Phys. Dept., BNL, USA)
MATSUDA Atsushi t~ 83 7f. 9:. (Fac. Sci., Univ. Tokyo)
MATSUDA Satoshi t~ 83 ~ (Fac. lntegr. Human Studies, Dept. Fundamental Sci., Kyoto Univ.)
MATSUI Tetsuo t~ # ~ ~ (Yukawa lnst. Theor. Phys., Kyoto Univ.)~ ~:t
MATSUKI Tsuneki t~
MATSUYANAGI Kenichi t~ ~p .pjf (Fac. Sci., Kyoto Univ.)
MElSON Jean-Marie (Div. Phys. Theor. lPN, lnst. Phys. Nucl., France)
MENGONI Alberto(Phys. Div., ENEA, Italy)
MIN Byung-Joo ~ fRj:rAe (Korea Atomic Energy Res. Inst., Korea)
MITARAI Shiro fiP~i5tite~ (Fac. Sci., Kyushu Univ.)
MITSUOKA Shinichi 7t Wi] ~ (JAERI)MIYACHI Takashi g:lti! -if:. (Cen. Nucl. Study, Univ. Tokyo)
MIYATAKE Hiroari gill (KEK, Tanashi)
MIZOI Yutaka iff. #r~
MORII Toshiyuki ~ # ~ q-j (Fac. Human Dev., Kobe Univ.)
MORIKAWA Tsuneyasu ~ JII '@ 1i: (Fac. Sci., Kyushu Univ.)
MORINOBU Shunpei ~ 1~ ~ ~ (Fac. Sci., Kyushu Univ.)
MOTOBAYASHI Tohru ~ 1* ~ (CoIl. Sci., Rikkyo Univ.)
MOTTELSON Ben R.
(Nordisk Inst. Theor. Fusik, Denmark)
MUELLER Ludwig(Phys. Dept., Univ. Padoba, Italy)
MURAKAMI Takeshi tt 1::. ~ (N atl. Inst. Radiol. Sci.)
NAGAI Yasuki 71< # *~:t (Fac. Sci., Tokyo Inst. Technol.)
NAGAMIYA Shoji 11< g iE is' (JHF Project Office, KEK)NAGASHIMA Yasuo !it lib *:;k: (Univ. Tsukuba)
NAKAJIMA Mitsuo t:p lib 7f.:;k: (Interdiscplinary Grad. Sch. Sci. Eng., Tokyo Inst. Technol.)
NAKAMURA Shogo t:p tt iE ~ (Fac. Ed., Yokohama Natl. Univ.)
NAKAMURA Takashi t:p ft ~!:lJ (Natl. Supercond. Cycl. Lab., Michigan State Univ., USA)
NAKAMURA Masanobu t:p ft iE 1~ (Fac. Sci., Kyoto Univ.)
NAKAYAMA Shintaro t:pLlJ1~*e~ (Fac. Integr. Arts Sci., Univ. Tokushima)
NIIZEKI Takashi $Jf ~ ~j: (Fac. Sci., Tokyo lnst. Technol.)
NORO Tetsuo [ff g ~:;k: (RCNP, Osaka Univ.)
NOTANI Masahiro [ff ~ ~~ Jt.
ODAHARA Atsuko IJ~83JJj(~r (Nishinippon Inst. Technol.)
OGAWA Masao IJ~}l1 ~ ~ (Interdiscplinary Grad. Sch. Sci. Eng., Tokyo Inst. Technol.)
OHTA Shigemi
83 iH ~ (KEK)
OKAMURA Hiroyuki Wi] ft "5t. Z(Dept. Phys., Grad. Sch. Sci., Univ. Tokyo)
OKAMURA Masahiro Wi] tt J§ 7R
ONUMA Hajime¥~(Chiba Inst. Technol.)
OOISHI Ryutaro *E~*e~ (Inst. Phys., Univ. Tsukuba)
OOYAMA Ken
LlJ ~ORIHARA Hikonojyo *lJJj(mzZR (Cycl. Radioisot. Cen., Tohoku Univ.)
OSHIMA Masumilib ~?1[ (J AERI)OTSUKA Takaharu
j~ -if:. is'(Fac. Sci., Univ. Tokyo)
OYAIZU Michihiro IJ~;WP?~7f.Jt. (KEK, Tanashi)
PENIONZHKEVICH louri(Flerov Lab. Nucl. React., Joint Inst. Nucl. Res., Russia)
PETROVICH Ilya (Flerov Lab. Nucl. React., Joint Inst. Nucl. Res., Russia)
RAURENT Henri(Div. Phys. Theor. lPN, Inst. Phys. Nucl., France)
REN Zhongzhou if t:p iJH (Nanjing Univ., China)

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272

m

RUAN (GEN) Jian-Zhi}l i6(ColI. Sci., Rikkyo Univ.)
SAGAWA Hiroyuki 1ft JII ~L ¥(Cen. Math. Sci., Univ. Aizu)
SAKAGUCHI Harutaka :tOC 0 i6 ~1: (Fac. Sci., Kyoto Univ.)
SAKAI Mitsuo :tOC it 7t:;R (KEK, Tanashi)(Tokyo Inst. Technol.)
SAKAI Kenji ?~ it fl
SAKURAGI Hiroyuki ~~L L(Fac. Sci., Osaka City Univ.)
SAMANTA Chhanda (Theory Group, Saha Inst. Nucl. Phys., India)
SATO Hikaru 1ft ni B~ (KEK)
SATO Hiroki 1ft Hi tf *'2.
SCHAEFER Markus(Phys. Inst., Univ. Goettingen, Germany)
SCHMIDT-OTT Wolf-Dieter(Phys. Inst., Univ. Goettingen, Germany)
SEDERWALL Bo(Royal Inst. Technol., Sweden)
SHIBATA Toshiaki ~ 83 flJ B)j (Tokyo Inst. Technol.)iI (Fac. Educ., Yamagata Univ.)
SHIMIZU Hajime i~lit)( (Fac. Sci., Kyushu Univ.)
SHIMIZU Yoshifumi
SHIMODA Tadashi T 83 iE (Grad. Sch. Sci., Osaka Univ.)
SHIMOURA Susumu T im ~ (ColI. Sci., Rikkyo Univ.)
SIGNORINI Cosimo (Phys. Dept., Univ. Padoba, Italy)
SOKOL Evgueni(Flerov Lab. Nucl. React., Joint Inst. Nucl. Res., Russia)
SUGAWARA Masahiko ;g JJj( J§ ~ (Chiba Inst. Technol.)
SUN Zuxun
1i L (Fac. Sci., Niigata Univ.)
SUZUKI Yasuyuki ~fJ
SUZUKI Katsuhiko ~fl£ ~ (RCNP, Osaka Univ.)
TAJIMA Yasuhisa 83 lib ~ ~ (Cycl. Radioisot. Cen., Tohoku Univ.)
TAKADA Eiichi ~ 83
(N at I. Inst. Radiol. Sci.)
TAKAHASHI Noriaki ~ fit ~ f!J3 (Grad. Sch. Sci., Osaka Univ.)(Inst. Space Astro. Sci.)
TAKAHASHI Tadayuki ~ fit ,~, ¥TAKAKU Seisaku ~ ~ i~ it (KEK, Tanashi)
TAKIGAWA Noboru 7~ JII ~ (Grad. Sch. Sci., Tohoku Univ.)
TAKIZAWA Makoto in 7i. IDit (Showa ColI. Pharm. Sci.)
TAMIl Atsushi ~:j:f: i¥ (Fac. Sci., Univ. Tokyo)
TANAKA Masahiko 83 $ ~ ~ (KEK, Tanashi)
TANOKURA Atsushi 83 lff it ~f (Fac. Sci. Technol., Sophia Univ.)
TENDOW Yoshihiko 7( ~ 7i ~TERAKAWA Atsuki ~}lI" ~t (Cycl. Radioisot. Cen., Tohoku Univ.)
TERANISHI Takashi ~ 1t9 ~ (Cen. Nucl. Study, Univ. Tokyo)
THOMPSON J. I.
(Univ. Surry, UK)
TOKI Hiroshi ± II&: tf (RCNP, Osaka Univ.)
TOYAMA Takeshi )ti- LiJ ~ (KEK)UENO Hideki L lff f§ tit (Fac. Sci., Osaka Univ.)
lff iE Ii (Min. Educ., Sci. Culture)
UNO Masahiro
WAKAMATSU Masashi ~ t~ iE ~ (Fac. Sci., Osaka Univ.)
WATANABE Yutaka ioc ill t§
WHITE Sebastian (Phys. Dept., BNL, USA)WU Heyu ~ fo(Inst. Modern Phys., Chinese Acad. Sci., China)
XU Shuwei 1~ ~t ~ (Inst. Modern Phys., Chinese Acad. Sci., China)
YAMAMOTO Sukeyasu LiJ::$: tt}i~ (Fac. Sci. Technol., Sophia Univ.)ill (Fac. Eng., Fukui Univ. Technol.)
YAMANISHI Teruya LiJ 1t9
YAMASHITA Yoshiki LiJ T 7i f!t (Hirosaki Univ.)
YANAGISAWA Yoshiyuki fgp ¥R ~ 1-r
YAZAKI Koichi
i1i~ ~ YOSHIMURA Koji E ft 115- PJ (Int. Cen. Element. Part. Phys., Univ. Tokyo)
YOSHINAGA Naotaka E 71< roJ 1f:. (Fac. Sci., Saitama Univ.)YOSOI Masaru w.~it fI (Fac. Sci., Kyoto Univ.)
ZHOU Xiaohong mJ Ij ... *1 (Inst. Modern Phys., Chinese Acad. Sci., China)

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Trainees
CHIKU Suenori

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(Inst. Phys., Univ. Tsukuba)
273

*FOUBERT Luc(ColI. Sci., Rikkyo Univ.)
FUKE Hideyuki t~~ Z(Fac. Sci., Univ. Tokyo)
FUKUCHI Tomonori t~ i& ~O ~Ij (Fac. Sci., Kyushu Univ.)
FUKUSAKA Shouichi t~ t& ~q. (Dept. Phys., Grad. Sch. Sci., Univ. Tokyo)
1:.
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FUTAKAMI Udai
GOMI Tomoko Ii ~ ijJ3 -=f (ColI. Sci., Rikkyo Univ.)
GOTO Atsudhi Ii ~ ~t (Tokyo Inst. Technol.)
HIGURASHI Yoshihide B ~ f* ~ (ColI. Sci., Rikkyo Univ.)
HIRAI Masanori 5f # lE if:2. (Fac. Sci. Eng., Saga Univ.)
HORlI Hideyuki #m # ~ ff (ColI. Sci., Rikkyo Univ.)
HORlKAWA Hirotsugu #m HI tf Iffl~ (Fac. Human Dev., Kobe Univ.)
1MAI Nobuaki 4'- # 1$ ijg(Dept. Phys., Grad. Sch. Sci., Univ. Tokyo)
IWATA Yoshiyuki :5 IE {t Z (ColI. Sci., Rikkyo Univ.)
Elt 1~ (Fac. Sci., Niigata Univ.)
KANAZAWA Yasunobu i:
KANEKO Tomohiro i: -=f ~ t-f (Fac. Sci., Univ. Tokyo)
KATO Hiromitsu 110 Ji 1ft 7C (Dept. Phys., Grad. Sch. Sci., Univ. Tokyo)
KINUGAWA Hiroto t<.}l1 1ft A (ColI. Sci., Rikkyo Univ.)
KOBAYASHI Hiroshi IJ"
Jt (ColI. Sci., Rikkyo Univ.)
KOMIYA Takefumi IJ" E ;t ~ (ColI. Sci., Rikkyo Univ.)
MAEDA Yukie M IE $ £(Dept. Phys., Grad. Sch. Sci., Univ. Tokyo)
MATSUDA Atsushi f'~ IE 7C ~ (Fac. Sci., Univ. Tokyo)
MAMURO Erika rB'~I!9!:£W (ColI. Sci., Rikkyo Univ.)
MINEMURA Toshiyuki
if;f ~ 1-j (ColI. Sci., Rikkyo U niv.)
MIYACHI Yoshiyuki '8 i& • Z (Cen. Integrated Res. Sci. Eng., Nagoya Univ.)
MIYAKAWA Takahiko '8}11" ~ (Fac. Sci., Tokyo Metropol. Univ.)
MIYAMA Masanori ~* LlJ iE if:2. (Fac. Sci. Eng., Saga Univ.)
if:!" :f.ti ~r. (Tokyo Inst. Technol.)
MIZUMURA Yuuki
if:!" {~iEi (Fac. Sci., Kyushu Univ.)
MOTOMURA Shinji
NAGAKURA Masaki :& ~ lE lit (Tokyo Inst. Technol.)
NAKANO Joe 9J ti" ~ (Cen. Nucl. Study, Univ. Tokyo)
NAKANO Eiji {rp ti" ~ PJ (Fac. Sci., Tokyo Metropol. Univ.)
NISHIYAMA Naoki i!B LlJ ~ lit (Fac. Sci., Niigata Univ.)
OGAWA Hiroshi IJ" 111 tf Iffl~ (Tokyo Inst. Technol.)
OHKUMA Kazumasa~~lE (Fac. Human Dev., Kobe Univ.)
OONISHI Tetsuya[§" tg" ~(Dept. Phys., Grad. Sch. Sci., Univ. Tokyo)
SAITOU Akito ~ Ji ijg ~ (ColI. Sci., Rikkyo Univ.)
SAKODA Seitaro :iE!1E[6t:t:J!m (Dept. Phys., Grad. Sch. Sci., Univ. Tokyo)
SAKUMA Tai 11:~ra' ~ (Tokyo Inst. Technol.)
SATO Miki 11: Hi ~ if:2. (Tokyo Inst. Technol.)
IE ~J,. (ColI. Sci., Rikkyo Univ.)
SAWADA Hirokazu
SEKIGUCHI Kimiko ~ 0 t -=f (Dept. Phys., Grad. Sch. Sci., Univ. Tokyo)
SERATA Masaki tlt.&83~* (ColI. Sci., Rikkyo Univ.)
SHIBATA Masataka ~ IE ~ ~1: (Fac. Sci., Kyushu Univ.)
SUETSUGU Kentaro **~*~~ (Tokyo Inst. Technol.)
SUGA Toshitaka 3J[ Jt fii!J. 1f- (Tokyo Inst. Technol.)
SUIGIOKA Makoto ;f~ /iYiJ wx: (Tokyo Inst. Technol.)
1f- $ (Tokyo Inst. Technol.)SUZUKI Takayuki if;TAKRUCHI Takeshi rr I*J ~ii (Fac. Sci., Konan Univ.)
TANIGUCHI Etsuji :fr 0 tR. ~ (Tokyo Inst. Technol.)
TOJO Junji~ Jill[(Fac. Sci., Kyoto Univ.)TORII Hisayuki ,~it ~ 1-j (Fac. Sci., Kyoto Univ.)
TSUTSUMI Takeshi ~ rmJIJ .;=t- (Fac. Sci., Kyushu Univ.)
UCHIYAMA Yasuhito I*J LlJ ~ 1= (Tokyo Inst. Technol.)
UEHARA Ayaka 1:.}Jj(~*{t (ColI. Sci., Rikkyo Univ.)
WATANABE Hiroshi iJi it Jt (Fac. Sci., Kyushu Univ.)
YAKO Kentaro *[Q]~*~~ (Dept. Phys., Grad. Sch. Sci., Univ. Tokyo)
YAMADA Kazunari LlJ IE - m (CoIl. Sci., Rikkyo Univ.)
Eft ~ (Fac. Sci. Technol., Sci. Univ. Tokyo)
YAMAMOTO Yasuchika LlJ

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YOGO Katsunori ~ ~ft 5l;f.2. , (ColI. Sci., Rikkyo Univ.)
YONEDA Kenichiro *EE~-e~ (Dept. Phys., Grad. Sch. Sci., Univ.. Tokyo)
YOSHIMI Akihiro ~ ~ ~?$ (Tokyo Inst. Technql.)

Atomic Physics Laboratory
Head
YAMAZAKI Yasunori Ll.J ~~Members* m.

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ANDO Kozo ~ ~ /lijlj
KANAI Yasuyuki ~ it 1* Z
NAKAI Yoichi q:t it ~ OURA Masaki
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SillMAMURA Isao ~ ft ~*KAMBARA Tadashi 1$ mt if.
KOJIMA Takao M. Ij, ~ ~l :K
NISHIDA Masarni ~ EE ~ ~OYAMA Hitoshi
Ll.J ~**

Visiting Members and Postdoctoral Fellows

AZUMA Toshiyuki~ 1T(Inst. Appl. Phys., Univ. Tsukuba)
CHIMI Yasuhiro ~ ~ ~ 5.l. (JAERI, Tokai Res. Estab.)
DATZ Sheldon(Oak Ridge Nat I. Lab., USA)DePAOLA Brett D.
(Kansas State Univ., USA)
FUJIMA Kazumi Ki r"" - ~ (Fac. Eng. , Yamanashi Univ.)
HARA Shunsuke mt ~ 1i' (Dept. Gen. Educ., Tsukuba ColI. Technol.)
HATTORI Toshiyuki ij[i g:~ 1~ ¥ (Res. Lab. Nucl. React., Tokyo Inst. Technol.)
HINO Ken-ichi B mt ~ (Inst. Appl. Phys., Univ. Tsukuba)
HIRAYAMA Takato f Ll.J #- A (Dept. Phys., Gakushuin Univ.)(Kochi Med. Sch.)HITACHI Akira Ji ill •HULDT Sven
(Lund Univ., Sweden)
HUTTON RogerICHIMURA Atsushi
ft ?¥ (Inst. Space Astro. Sci.)
ICHIOKA Toshiyasu
IHiJ flJ ~(Grad. Sch. Arts Sci., Univ. Tokyo)
IGARASHI Akinori n+oo.SJHW (Fac. Eng., Miyazaki Univ.)
ISHII Keishi E
Z (Fac. Sci. Eng., Ritsumeikan Univ.)
ISHIKAWA Norito E)l1 ~ A (JAERI, Tokai Res. Estab.)
ITOH Akio ffr Ki f.k ~ (Fac. Eng., Kyoto Univ.)
ITOH Yoh ffr Ki ~ (Fac. Sci., Josai Univ.)
IWASE Akihiro :5 Mi ~ 11: (JAERI, Tokai Res. Estab.)
KAGEYAMA Kensuke iIi Ll.J ~ 1i' (Fac. Eng., Saitama Univ.)
KANEKO Shinichi ~ ~ ~ (Fac. Sci., Tokyo Inst. Technol.)
KAWATSURA Kiyoshi JII 00 rn: (Fac. Eng. Design, Kyoto Inst. Technol.)
KIKIANI Boris(Tbilisi State Univ., Georgia, USA)ft if. ~ (Kochi Univ. Technol.)
KIMURA Masahiroft~(Sch. Allied Health Sci., Yamaguchi Univ.)
KIMURA Mineo
KINK Ilmar(Lund Univ., Sweden)
KITAJIMA Masashi ~t ~ ~ 9::. (Fac. Sci. Technol. , Sophia Univ.)
KOBAYASHI Nobuo Ij, ift 1~ ~ (Dept. Phys., Tokyo Metrop. Univ.)
KOHARA Takao Ij, mt #- ~ (Fac. Sci. , Himeji Inst. Technol.)
KOIKE Fumihiro Ij, 71ft )c tf (Sch. Med., Kitasato Univ.)
KOIZUMI Tetsuo Ij, jjt ~:K (Dept. Phys., Rikkyo Univ.)
KOMAKI Ken-ichiro IJ'!&;PJf-e~ (Grad. Sch. Arts Sci., Univ. Tokyo)
KORENMAN Grigori(Moscow State Univ., Russia)
KOWARI Kenichi Ij, ~tl ~ (Dept. Appl. Phys. Chern., Univ. Electro-Commun.)
KUROTA Naoshi ~ EE ~ it (JAERI, Tokai Res. Estab.)~ e~(Natl. Res. Inst. Police Sci.)
KUROKI Kenro ~MARTINSON Indrek (Lund Univ., Sweden)(Dept. Pathol. , Tokyo Med . Dent. Univ.)
MATSUO Takashi tl f;§
MATSUZAWA Michio tl
Jm ~ (Dept. Appl. Phys. Chern. , Univ. Electro-Commun.)

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MITAMURA Tohru :=H3ft mt (Fac. Eng., Himeji Inst. Technol.)
MIZOGAWA Tatsumi iflf)ll JiK E (Nagaoka ColI. Technol.)
MOHRI Akihiro =t flJ BJ3 t-f (Fac. Integrated Human Studies, Kyoto Univ.)
MUKOYAMA Takeshi rPJ LlJ ~ (Inst. Chem. Res., Kyoto Univ.)
NAKAMURA Masato ~ ft iE A (ColI. Sci. Technol., Nihon U niv.)
NISHIDA Nobuhiko W H3 f~ ~ (Fac. Sci., Tokyo Inst. Technol.)NISHIMURA Tamio W ft .B?: ~NYSTROM Bosse
OHTANI Shunsuke~ 1~ 11'(Inst. Laser Sci., Univ. Electro-Commun.)
OKAYASU Satoru IiYiJ 1; 'It (JAERI, Tokai Res. Estab.)
OKUNO Kazuhiko ~ lff fO ~ (Dept. Phys., Tokyo Metrop. Univ.)
OSHIMA Nagayasu
1ifb 71<
SAKATA Hideaki :t& H3 ?Ii:. BJ3 (Fac. Sci., Tokyo Inst. Technol.)~(Fac. Sci., Kobe U niv.)
SAKURAI Makoto t* #SATO Hiroshi ~ ~ i-*!1: (Fac. Sci., Ochanomizu U niv.)
SATOH Kazuhiko ~ ~ - ~ (Fac. Sci., Tokyo Inst. Technol.)
SATOH Yukinori 16: ~ ¥ if.C (Res. Inst. Sci. Meas., Tohoku Univ.)
SCHMIDT-BaCKING Horst(Univ. Frankfurt, Germany)
SEKIOKA Tsuguhisa ~ fHiJ Iffl~ ~ (Fac. Eng., Himeji Inst. Technol.)
SHIBATA Hiromi ~ H3 tft ~ (Res. Cen. Nucl. Sci., Univ. Tokyo)
SHIMA Kunihiro 1ifb t~ t-f (Tandem Accel. Cen., Univ. Tsukuba)
SHIMAKURA Noriyuki 1ifb ~ if.C Z (Fac. Sci., Niigata Univ.)
SOEJIMA Kouichi ;U ~(Fac. Sci., Niigata Univ.)
JjJ (Electrotech. Lab.)SUZUKI Isao ~~TAKAYANAGI Toshinobu j@j ~~ ~ ~ (Fac. Sci. Technol., Sophia Univ.)
TAWARA Hiroyuki 1t t-f Z (Natl. Inst. Fusion Sci.)TERASAWA Mititaka ~ i~ ffiJ ~ (Fac. Eng., Himeji Inst. Technol.)
THURIEZ Sebastien
TOSHIMA Nobuyuki p 1Il~ f~ ¥(Inst. Appl. Phys., Univ. Tsukuba)
TSUCHIDA Hidetsugu ± H3 jij:}( (Fac. Sci., Nara Women's Univ.)
URAMOTO Seiichi im::$: ~ WAKIYA Kazuyoshi ,Ii, ~ - ~ (Fac. Sci. Technol., Sophia Univ.)
WATANABE Shinichi ill ill f~ (Dept. Appl. Phys. Chem., Univ. Electro-Commun.)
YAGISHITA Akira ~p T~
(KEK)
YODA Jun ft( E8 llMJ (Natl. Res. Lab. Metrol.)
YOSHINO Masuhiro E mt ~~.l. (Lab. Phys., Shibaura Inst. Technol.)ZOU Yarning(Shanghai Jiao Tong Univ., China)

*-

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*-

i* -

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Trainees
CHIBA Daisuke -T;j~11' (Fac. Sci. Technol., Sophia Univ.)
FUJINO Atsushi ~ 'f ~ (Dept. Phys., Rikkyo Univ.)
HORI Masaki jjffi iE ttt (Dept. Phys., Grad. Sch. Sci., Univ. Tokyo)
ITO Akira fJJ- ~ If% (Fac. Sci. Technol., Rikkyo Univ.)
IWAI Yoshio -!fi # H ~ (Grad. Sch. Arts Sci., Univ. Tokyo)
KAMEl Takehito ~ #t(Fac. Sci. Technol., Sophia Univ.)
KAWAE Sotaro JlliI*j.;Jm (Dept. Eng. Sci., Kyoto Univ.)
KIMURA Yasuyuki
fI ~ Z (Dept. Eng. Sci., Kyoto Univ.)
MATSUSHIMA Hiroshi fJ} 1ifb It. (Grad. Sch. Arts Sci., Univ. Tokyo)
NAKANO Tomohide frp mt 17:. jij (Dept. Eng. Sci., Kyoto Univ.)
OGURA Kunihiro IJ' ~ t~ 7i (Fac. Sci. Technol., Sophia Univ.)
ONO Yasuhiro IJ' lff *"51.. (Fac. Sci., Tokyo Inst. Technol.)
SUGIYAMA Yukiko ~~ LlJ ¥ -=f (Fac. Sci. Technol., Sophia Univ.)
TAGUCHI Yoshio H3 0 ~(Fac. Sci., Tokyo Inst. Technol.)
WHITEHEAD Richard (Dept. Phys., Sci. Lab., Univ. Durham, UK)
YAMASHITA Kenya LlJ T W ~ (Dept. Phys., Grad. Sch. Sci., Univ. Tokyo)

*-

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276

Muon Science Laboratory
Head
NAGAMINE Kanetada 71<. ~ ~ ,["Members
ISHIDA Katsuhiko ::fi E8 M} $MATSUDA Yasuyuki ;f~ E8 $ ¥NAKAMURA Satoshi N. Ii=';ft 19'"YAGI Eiichi )\**-KOYAMA Akio 'J~ llJ BS 1$
MATSUZAKI Teiichiro t~~tj[m~~WATAN ABE Isao ill jI Jj] 1$

Visiting Members and Postdoctoral Fellows
AKIMITSU Jun {j( 7t *4! (CoH. Sci. Eng. , Aoyama Gakuin Univ.)
AKIMOTO Katsuhiro f* /.$: 5l i$ (Inst. Mater. , Univ. Tsukuba)
ASAI Kichizo 13t it E jl (U niv. Electro-Commun.)DAS Prasad Tara (Dept. Phys., State Univ. New York, Albany, USA)FU JITA Ayumi ~ E8 a; ~ J-;.
FUKAYA Atsuko i* ~ ~i -=tHASHIMOTO Masashi ~ /.$: ~ 9:. (JAERI, Tokai Res. Estab.)
HIGEMOTO Wataru ~ /.$: 8(KEK)
HIYAMA Emiko ~~llJ~~-=tIWASAKI Masahiko :5 Ih~ ~ $(Dept. Phys. , Tokyo Inst. Technol.)
KADONO Ryosuke r~ If .& ~ (KEK)~(JAERI, Tokai Res. Estab.)
KATO Mineo 110 Ii
KAWAMURA N aritoshi iar;ft nX: •KINO Yasushi
It Eft iit (Fac. Sci. , Tohoku Univ.)
KRISHNAMURTHY Vemuru
KUROSAWA Kiyoyuki ~ iR i. iT (JAERI, Tokai Res. Estab.)
MACRAE Roderick M.
MARUYAMA Takahiro JL llJ ~i ¥~ (Inst. Mater., Univ. Tsukuba)
B~
MATSUSHITA Akira t~ T
MIYAKE Yasuhiro = ~ Eft t-f: (KEK)NISHIDA Nobuhiko ~ E8 1§ ~ (Fac. Sci., Tokyo Inst. Technol.)NISHIYAMA Kusuo @ llJ ;fJt ~ (KEK)
PRATT Francis L.
SHIMOMURA Koichiro T;fti~-~~ (KEK)
SAKAMOTO Shinichi :roc 5C ~ (KEK)
STRASSER Patrick
TANASE Masakazu {JlI]. if fo (JAERI, Tokai Res. Estab.)
TORIKAI Eiko ,~ll ~ -=t- (Fac. Eng., Yamanashi Univ.)*

TraineesOOHIRA Seiko
TOYODA Akihisa"**~ ~ -=t(Grad. Sch., Univ. Tokyo)~ E8 ~),..
(Grad. Sch., Univ. Tokyo)

Magnetic Materials Laboratory
Head
KATSUMATA Koichi M} X *li Members
HAGIWARA Masayuki~

mt 1& ¥

MATSUDA Masaaki;f~ E8 ~ Jl§

277

Computational Science Laboratory
Head
EBISUZAKI Toshikazu ~ ~~ 1~ Members
SUMIYOSHI Kohsuke

f! E 7t 1r

Visiting Members and Postdoctoral Fellows
MIURA Hitoshi ~ 1m j5j
SHIMIZU Tetsuya£~ illj. *-Inorganic Chemical Physics Laboratory
Head
TAKAMI Michio ~ J! ii ~Members
AMBE Shizuko 1i: fr~ fJ ~MATSUO Yukari t,t}~EI3jtfIJ

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ARAI Nobuaki )it # 1~ 1[. (Dept. Fisheries, Kyoto Univ.)
KAWAI Jun ?PJ -g.. iii' (Dept. Metallurgy, Kyoto Univ.)~
HUI Qin ~Trainees
HASEGAWA Tomotake *~)II~::st (ColI. Eng., Hosei Univ.)
TONOMURA Atsuro ~ ft if ~~ (ColI. Eng., Hosei Univ.)

Nuclear Chemistry Laboratory
Head
AMBE Fumitoshi 1i: $ X 1i&.
Members
KOBAYASHI Yoshio

IJ'\

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TAKEMATSU Noburu

Visiting Members and Postdoctoral Fellows
ALEXANDER T. Roeck(Max-Planck Inst. Stuttgart, Germany)
BABA Hiroshi ,~j~ 7.i (Fac. Sci., Osaka Univ.)
CHANG Zheng 1t
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NASU Saburo ~~ 3J{
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OHKUBO Yoshitaka :*'l\f~g~ (Res. React. Inst., Kyoto Univ.)
OISHI Shigeo :* {j a a (Sch. Health Sci., Kanazawa Univ.)
OKAMOTO Yayoi /iliJ
5~ ~(Showa ColI. Pharm. Sci.)
SAITO Tadashi ~ Mi ~ (Fac. Sci. , Osaka Univ.)
SHIBATA Seiichi ~ ill wx. (Res. React. Inst. , Kyoto Univ.)
SHIN OHARA Atsushi 1i)Jj( J!j (Fac. Sci. , Nagoya Univ.)
YOKOYAMA Akihiko ;fl ill f!J3 ~ (Fac. Sci. , Osaka Univ.)-=*

Trainees
ABE Daisuke ~iiJ fr~
fjij (Fac. Sci. , Toho Univ.)
ARAKI Hirokazu
7i (Fac. Sci. , Osaka Univ.)
DAIRAKU Tomohisa :* ~ ~D 'l\ (Fac. Sci. , Nagoya Univ.)
HAYAKAWA Nobutaka .!f!.)l1 f~ ~i: (Showa ColI. Pharm. Sci.)IRIGUCHI Yuko A 0 1~ ~ (Fac. Sci. Living, Osaka City Univ.)
MORIMOTO Shinya ~::<$: ~ ~ (Fac. Sci. , Osaka Univ.)

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MUKAI Kazuhiko (oJ ;to(Fac. Sci., Osaka Univ.)
MURASE Nobuyuki t1 iii 1$ ¥(Shizuoka Inst. Sci. Technol.)
MURATA Chihiro t1 EEl -=f- ttl- (Fac. Sci., Nagoya Univ.)
MUROYAMA Toshiharu ~ LlJ 1~ i1!i (Fac. Sci., Nagoya Univ.)
NAKANISHI Kouichi ~ [Ii 11- m (Shizuoka Inst. Sci. Technol.)ODA Hirotaka IJ'\ EEl J[ jt (Fac. Sci., Nagoya Univ.)
OIKAWA Shinji If}ll ~ P] (Fac. Sci., Kanazawa Univ.)
SANADA Jun ~ EEl ilij (Fac. Sci., Osaka Univ.)
SOGA Kyoko ~ ~ :m -=f (Fac. Sci., Nagoya Univ.)
SOTOGAKU Naoki ~i- P4 ~ ~t (Showa CoIl. Pharrn. Sci.)
TAKAHASHI Yoshio ~~ ~(Fac. Sci., Univ. Tokyo)mChemical Dynamics Laboratory
Members
KIMURA Kazuie
t1 -

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USHIDA Kirninori:H: EEl 1.~ ~lVisiting Members and Postdoctoral Fellows
KAZAMA Shigeo
m: tt (Dept. Phys., Chuo Univ.)
SHARMA Surnitmra'Trainees
ITOH Noriaki W Hi ~ BE (Osaka Inst. Technol.)
KANEKO Junichi i: -=f ~ (JAERI, Tokai)

Cellular Physiology Laboratory
Head
HANAOKA Furnio 1t ~ X tft
Members
KITAYAMA Shigeru ~t LlJ itt
YATAGAI Furnio :fr.EElJ!x5t
Trainees
ANDO Koichi !fi: Hi " - (N atl. Inst. Radiol. Sci.)
FURUSAWA Yoshiya "CI
1* tQ (Natl. Inst. Radiol. Sci.)
HAMA Yoshirnasa i~ ~ J§ (Sci. Eng. Res. Lab., Waseda Univ.)
HASE Yoshihiro *:fr. ~ 7.i. (JAERI, Takasaki Rad. Chern. Res. Estab.)
HOSHINO Kazuo £ ~ - til (Natl. Inst. Radiol. Sci.)
ITO Hisao W 0.. 5t (Sch. Med., Chiba Univ.)
IS h- (Natl. Inst. Radiol. Sci.)
ITSUKAICHI Hirorni 11 B
KANAI Tatsuaki i: #- Jt ~ (Natl. Inst. Radiol. Sci.)(Natl. Inst. Radiol. Sci.)
KASAl Kiyorni j£ #- 1W
KAWACHI Kiyornitsu illT r*J 1W 7t (Natl. Inst. Radiol. Sci.)
KOBAYASHI Yasuhiko IJ'\ if* ~(JAERI, Takasaki Rad. Chern. Res. Estab.)f%" if: (Natl. Inst. Radiol. Sci.)
LI Ryonpha
MATSUFU JI Naruhiro tl Hi $: ~J,. (N atl. Inst. Radiol. Sci.)MINOHARA Shinichi ~ m: 1$ (Natl. Inst. Radiol. Sci.)
MURAKAMI Masahiro t1 J:. iE ~J,. (N atl. Inst. Radiol. Sci.)
Hi Iffij;f.t (Natl. Inst. Radiol. Sci.)
SAITO Mizuho
SASAKI Hiroshi 16:4* ~J,. (Fac. Med., Kyushu Univ.)
SHIKAZONO Naoya J1[ ~ ~ ~ (JAERI, Takasaki Rad. Chern. Res. Estab.)
SOGA Furninori ~ ft X '§' (Inst. Nucl. Study, Univ. Tokyo)
TANAKA Atsushi EEl ~ ?.!f. (JAERI, Takasaki Rad. Chern. Res. Estab.)
TOMURA Hirorni )Ii- t1 i1!i
(N atl. Inst. Radiol. Sci.)
WATANABE Masarni iJi ill iE G (Fac. Pharrn. , Nagasaki Univ.)

i*

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LlJ T J§;jz

YAMASHITA Shoji(Natl. Saitarna Hospital)

Plant Functions Laboratory
Head
YOSHIDA Shigeo E B3a~Members
ABE Tornoko+~iiJ tiB ~Visiting Members and Postdoctoral Fellows
BAE Chang-Hyu ~ J§:f?ts
HASHIMOTO Takashi~l(Dept. Biosci., NAIST)
MATSUYAMA Tomoki tl ill ~D f!t
MIYOSHI Kazumitsu
E - 7tSATO Furnihiko 1ft Jii X ~ (Dept. Agric. Chern., Kyoto Univ.)
SATO Shinobu 1ft Jii Jj, (Inst. BioI. Sci., Tsukuba Univ.)
SUZUKI Kenichi iii"~
(Suntory Ltd.)it
TAKAHASHI Yoshiko ~

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MIYAGAI Mashu g 7f- Jff mJ (Dept. Biosci., Teikyo Univ.)
MUTO Sonoko m:Jii-fO)+ (Fac. Hortic. , Chiba Univ.)
TAKAHASHI Hideki ~~ f!t(ColI. Agric. Vet. Med., Nihon Univ.)m

Microbial Toxicology Laboratory
Head. YAMAGUCHI Isarnu ill 0~
Members
AR1E Tsutornu

tJ

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Visiting Members and Postdoctoral Fellows
GOUTHU Satyanarayana
NOSE Yasuhiro fm ~Jt=*

Cellular and Molecular Biology Laboratory
Head
SHIBATA Takehiko ~ ill m: ~Members
LING Feng~

1m

Trainees
YOSHIMASU Masatoshi

280~ iIrl: ~ i~(Sch. Agric., Nihon Univ.)

Division of Experimental Animal Research
Head
KUSAKABE Moriaki B T1l~~BH
Members
IKE Fumio 7tf! fl~ ~HIRAIWA Noriko ~ E $.:r*

YOSHIKI Atsushi fi
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TSUKADA Teruyo j~ EE ~ 1t

Visiting Members and Postdoctoral Fellows
POIRIER Christophe
YODA Yoshika 1tt EE ~ W (Japan Sci. Technol. Corp.)

Safety Center
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HARASAWA Kaoru JJj( ¥R. •MATSUZAWA Yasuhide f~ ii 17: ~SHINOHARA Shigemi ~]Jj{ IX CYAMANAKA Akira LlJ {$ II3t

KAGAYA Satoru 1Jo~~ fR
MIYAGAWA Makoto '8 JII ~ §UWAMINO Yoshitomo 1:.;ft ~ n)j
YOSHIKI Hajime fi ~ ~Radioisotope Technology Division
Head
YATAGAI Fumio~EEJ!Jt:=:K

Visiting Members and Postdoctoral Fellows
FU JIE Akio Ii!it Ai (Furuuchi Chemicals)
GORDON Alasdair
KAGAWA Yasuhiro W 111 ~ i1!f (Toray Res. Cen. Inc.)
MAEZAWA Hiroshi 1W
tt (Fac. Med. Technol., Tokushima Univ.)
MORIMOTO Shigeko ~IX -1- (Japan Space Forum)
OGURA Koichi IJ'\ ~ ffJi:. (ColI. Ind. Technol., Nihon Univ.)
SUZUKI Makoto if;'13:
SUZUKI Masao jf;'
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(Fac. Pharm., Nagasaki Univ.)

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KITO Masatoshi~j J§ ~lj(Fac. Sci. Eng., Waseda Univ.)
INOUE Kensuke :#- L ~ 1r (Fac. Sci. Eng., Waseda Univ.)
OKA Toshitaka wu(Fac. Sci. Eng., Waseda Univ.)
KUROBE Toshihiro
1l~ ~Ij tf(Fac. Sci. Eng., Waseda Univ.)

a*
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281

AUTHOR INDEXABE Ryo~iiJtt~?'f

5

EATON Gordon H.

~iiJtt~1:DT

ABE Tomoko

145, 146, 147, 148

40, 41, 42, 43

ECCLESTON Roger S.

103

EGUCHI-KASAI Kiyomi

iID (jt:#) i~~

JE.:sT.,.
77~lJj( flJ 7t
3

ENDO Kazutoyo

AKAGI Hiroyasu!)F*~*

5

ENOMOTO Shuichi

AKAI Hisazumi~#'l\*'i\!.

79

ADACHI Minoru

AIHARA Toshimitsu

79

AMANO Ryohei~!f'&:;:Y:

AMBE Fumitoshi*tt~ Jtfi&~$~T

AMBE Shizuko
ANDO Kozo~ni~t:::AOI Nori

108

Kia !it

ARIMA Akito~,~eJjA

ASAHI Koichiroj@229,230142

57, 5818, 19, 20, 21, 23, 26, 27,

~:7t

m~~T

BACK Torbjorn

56

BADONO Shinro,~~J1t~

BATYGIN Yuri

44

FUJISHIMA Shiro

Ki~9:eJj

193, 197, 206

229

28, 29, 30

AWAYA Yohko

3

AiEB $If*if-£!~ASAMITSU Atsushi

Ki~lEmFUJITA Shin~ ~ fittw:

ARI G A Takehiro

77, 81~

FUJIWARA Ichiro

jflJj( - £!~135

FUKAO Tetsuhiro

i*~fg'*

72

FUKAYA Atsuko

i*~~tT

114

FUKE Hideyuki

~*~Z

165

FUKUDA Mitsunori ~ EB :7tJIIJi
72, 79FUKUDA Naoki ~EBi1!~f67,68,70,74, 75,77,78
FUKUDA Shigekazu~EBa-72, 77, 79, 81

FUKUDA Tomokazu~ EB ~fD

70~#t,{jTFUKUI Yuko

163

68

GAl Moshe

82

GEISSEL Hans
83

82, 83

1i*}t:;k5654, 56GORDEN Eugene Borisovich

CHIBA Toshiya-T~fIJ~

186, 191, 208

GORDON Alasdiar

-T~H~

218

GOTO Akira

CHIMI Yasuhiro

92D~,*~1-

99

CHULKOV Leonid

83

CORTINA Dolores

83

104

154, 155f~f&ni

5, 135, 179, 182, 184, 186, 191,
193, 195, 197, 199, 201, 203,
205, 206 , 208, 210

GOTO YujiCZAJKOWSKI Serge

82

DINH DANG Nguyen

M:1Jf~*,'it',~DUTTA Chizuko M.

73, 78~.1~Z

GONO Yasuyuki

CHIBA Yoshiaki

DOKE Tadayoshi

162, 163
71, 80

1iP*~~T

GOMI Tomoko
85

152

82

GOKA Tateo

80

50

59

ili~Hi-tl1

GOLOVKOV Mikhail

CEDERWALL Bo:ffl-~*~

t!l!fJ!!.:;:Y:

FURUSAWA Yoshiya

82

62, 64, 65, 66

71,73,80

FUNAHASHI Haruhiko
FURUNO Kohei

BUENKER Robert J.

144, 154, 155, 156,
190

~J;&~q-FUKUSAKA Shoichi

BEAUMEL Didier

BOYD Richard N.

146~1l9~rA1

FUKUNISHI Nobuhisa

BLANK Bertrum
BOUE Frederic

229, 230

109

91, 92 , 96

82

BOCHKAREV Olegjf}]Ui~9::

FUJIWARA Atusi

FULOP Zsolt

BAUMANN Thomas

82

FUJIMAKI Masaki

122, 123, 125, 133
73

1J

FORSTER Andreas

5, 17967, 68, 70, 73, 74, 77, 78

~iI

226

jfEB=£!~AOKI Yuka W*Ei31!f61
ARAKAWA Takesi JiLJII ~~ARIE Tsutomu

FOREST Etienne

44,46,48,50

FUJITA Jiro

25

w# ~

~-9-~ A

EN'YO Hideto

121122, 125, 131, 132, 133

92, 93, 94, 95*

ANDO Yoshiaki
ANSARI Ahmad

121, 122, 123, 124, 125,
134

133
73, 167~iiJT~9')<" h.

ALONSO Jose R.

tI*3%-106

AKIYAMA Kazuhiko f*!lJfD~
AKIYOSHI Hiromichi fk=g~7E
AKOSHIMA Megumi

149

122, 125
127, 130, 131, 132, 133,

f**5iiif:

AKIMOTO Katsuhiro

iinifDa85

f&ni1il=

GOUTHU Satyanarayana~i

16, 26, 27, 28, 29 , 30

169, 172

GROSSE Eckart

82

G U J ian-Ping

85

HA Choongkoo

79

37,44,45,46,47,48,52
142

*Kmti&¥HAGIWARA Masayuki

7~83;jf

HAMADA Akira

114

86

~r:pJJtJi

HAMANAKA Hiromi

175

1M AI Ken'ichi

4-:#-~ -44,47,48,50,52

IMAI Nobuaki

4-:#-f~fJIj

68, 70, 74, 78:#-;ftf~1£

IMURA Nobumasa

HANAOKA Fumio

fEliYilJta

151, 154

INABE Naohito

HARUYAMA Seigo*uHiE1?i-

10

INOUE Tadashi

124

fffiillfi.1A:#- L iE

5,67
148

HASE Yoshihiro:&:~*i\!. 7i;

144

ISHIDA Katsuhiko

HASEBE Hiroo:&:~$r€ia

3;083 'tR65, 66ISHIDA Takayuki ;083fi.1Z
116:&:~JIIW-

HASEGAWA Kenichi*~JII*e~

HASEGAWA Taro

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82,83

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191

HIGEMOTO Wataru~*

HIGUCHI Hiroyoshi

mDJt~

HIGURASHI Yoshihide
HINO Satokog

B~1f;;s+;oJII~iB~

113

ISHIKAWA Norito;oJII1tA

99, 100

ISHIZUKA Takeo;o:t~m:~57, 58ISSHIKI Hiroshi--fu 1f
5
rtf JllqTfD

86

ITIKAWA Yukikazu

177

ITO Hisao

W*~~

152

73

ITO SachikoWEi~+

67, 72, 75, 229, 230

124

ITOH Akio

WEif*~

90

WEilD-tl!

ITOH Kazuya S.

36

f#1£fJIj
f# 1£#2.

HIRAI Masaaki

78,81

109, 110, 112

B ¥~*~£~IDit-e~

HIMENO Seiichiro

44, 48, 50, 52, 54, 56 ,68, 70, 72, 73, 74, 77,

ISHIKAWA Masayasu

65
37, 44, 45, 46, 48, 50, 52

HELLSTROM Margareta;omt1£~

ISHIHARA Masayasu

57:tIBr:p~i5

HATANAKA Kichiji

40, 41, 42, 43, 140, 173

40

.m* ~

HASHIMOTO Satoshi
HAYASHI Naoki

175
106

frt*~9:HASHIMOTO Masashi;o83Im~ISHIDA Satoru

62, 63, 64, 65, 66, 161

ffrEi~BB

70,73

ITOH Noriaki

36, 37, 68

HIRAIWA Noriko ~:E~ +156
HIRAKAWA Tetsuya fJlI'fg"-tl!
58

ITOH Yoh WEi ~96
ITOH Yoshiko -@tJ!:[7¥+135
ITSUKAICHI Hiromi Ii B rtf"(} 0 J-;..

HIRATA Daisy

IVANOV Marian

HIRAI Masanori

22

137

83

HIROSE Takayuki
HIRSCH Gerhard

Jt.ifii~¥

HIRUNUMA Rieko~mflJiI+HISANAGA Isamu

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57

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HOMMA Takayuki*ra~~tz

5

IWASAKI Masahiko::'fi~~~~

122, 124, 125, 127

HOSAKA Kazumotom:

HULDT Sven~

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37
180

92,93,94, 95~M13t~HYODO Toshio

ICHIHARA Takashi

44, 46, 48, 50, 53, 65,
66

ICHIKAWA Atsuko
ICHIKAWA Ryuji

rtfJllilii+
52
rtfJlIM=
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IDEGUCHI Eiji

IGARASHI Akinori

54, 56,68,78

11+ JJi.S)H~1j

IKEZAWA Eiji

II

it!?L1L=~it!?¥R~ =83

JEONG Sun-Chan

58

KADONO Ryosuker'~ N.~
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118

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3,186,191

5, 179.83 1f 147
KAMBARA Tadashi 1$mt 1£
90, 91, 92, 93, 94, 95,
KAMADA Hiroshi

98, 99, 100, 102

KAMEl Takehito

1l:#-m:f=

KAMIGAITO Osamu

97

L:@9H,*-

5, 186, 191, 193, 195,
208

KANAI Tatsuaki

1fi::#-)tSA

149, 152

KANAI Yasuyuki

1fi:#~z96, 97, 98

1fi:+*i\!:KANEKO Shin-ichi 1fi:+ ~ KANEKO Junichi

5, 188, 193, 210

42,17399, 10088#mt1[+
152
IKEDA Hiroshi it!? 83 1f
100
IKE Fumio it!? ~~~156
IHARA Noriko

IKEGAMI Kumio

67, 68, 70, 73, 74, 77, 78::'fi 83 il 135
IWATA Yoshiyuki ::'fi83f!z
73
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208 , 210

VIIRIKEN Accelerator Progress Report Vol. 32~n3~.liil]~/lX: 11 ~ (1999) 3 fJ 20 B

rr ~/lX: 11 ~ (1999) 3 fJ 31 B
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