ISSN 0289-842X

RIKEN
Accelerator
Progress Report
vol.

27

理化学研究所

The Institute of Physical and Chemical Research (RIKEN)RIKEN Accelerator Progress Report i1 (Q) (Q) ~January-December U 1/ 1/ ~!~ it. ~ Mf ~ jifT

The Institute of Phys;cal and Chem;cal Research (RIKEN)
Wako-slt;, Saitama, 35J-OJ JAPANEditors
A. AndoM. HaraT. Ichihara

T. Kambara

Y. Miyazawa

Y.Ohkubo

1. Shimamura

M. Takami

E. Vagi

S. Yamaji

Y. YanoF. Yatagai

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

CONTENTS
I.

Page
PREFACE .............................................................................. 1

II.

OPERATION OF ACCELERATORSRRC Operation .....................................................................

3

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

5

AVF Cyclotron Operation ...........................................................

6

Tandetron Operation ...............................................................

8

III.

RESEARCH ACTIVITIES

1.

Nuclear Physics
TheoryReaction Cross Sections of Light Isobars (A = 17) in the Glauber Model9. t'IOn R eact'Ion ................................. .
' t ep P rocess In. the 14 0 D'lssocla
M u It IS

10

El Giant Resonance in 220 ........................................................ .

11

Isoscalar Monopole Vibrations around Thermal Equilibrium ........................ .

12

Classical Quantization of ,-Soft Rotor .............................................. .

13

Tilted Axis Rotating States in 1820s Yrast ...... ............... .................... .

14

Asymmetric Nuclear Matter and Finite Nuclei ...................................... .

15

Neutron-Skin and Proton-Skin Formations in Exotic Nuclei Far from Stability ...... .

16

How Many Nuclides Do Exist? ..................................................... .

17

Systematics of Alpha Q-values: Potential Dependence of the Alpha
Decay Life Time ................................................................... .

18

Relativistic Density Dependent Hartree Approach for 16 0, 40Ca, and 208Pb ......... .

19

Systematic Study of Sr Isotopes in the Relativistic Mean Field Theory .............. .

20

Relativistic Mean Field Theory for the Isotope Shifts of Ba, Cs, and Xe ............. .

21

Instability of the Degenerate Electron Gas ......................................... .

22

Quasiparticle Properties and the Dynamics of High-Density Nuclear Matter ......... .

23

General Formula of the Coalescence Model ......................................... .

24

Nuclear Recoil Effects in e+ -e- Pair Production through 0+-0+ Transition .......... .

25

Distribution of Perturbative Gluon in the MIT Bag Model .......................... .

26

Momentum Evolution of the Twist-three Part of the Spin-dependent
Structure Fu.nction ................................................................. .

27

Color Confinement, Quark-Pair Creation and Dynamical Chiral-Symmetry
Breaking in the Dual Ginzburg-Landau Theory ..................................... .

28

First-Order Phase Transition with Global Z3 and Z4 Symmetry ..................... .

29

Experiment
Study of a Decays Following 40 Ar Bombardment on 238U

30

Production of High-Spin Isomer Beam ...............................................

31

High-Spin States of l44Pm ..........................................................

32

High-Spin States of l45Sm ...........................................................

33

Coincidence Measurements for Neutrons and a Particles from the Fragmentationof 6He at 800 A MeV...............................................................

34

Measurement of Light Charged Particle Emission in Coincidence with Fission
Fragments from 84Kr + 27 AI, 56Fe at 10.5A MeV ....................................

35

Neutron Emission in the 40 Ar + l16Sn Reactions at E/ A = 30, 37 MeV /u ...........

36

Charged Particle Emission in 40 Ar + natNi Reactions at E/ A = 30 MeV... ..........

37

Spin-Isospin Excitation in sd-Shell Nuclei Studied by (d,2He) Reactions... ...........

38

Measurement of Analyzing Powers for the d + p Elastic Scatteringat Ed = 270 MeV ...................................................................

39

Measurements of the Tensor Anall,zing Power Axx* for Deuteron Elastic
Scattering from l2C, 40Ca, and 20 Pb at Ed = 270 MeV............ ........ ... .. .. ..

40

e2C,l2N) Charge-Exchange Reaction at E/ A = 135 MeV............................ 41

2.

Measurement of Quadrupole Moments for the Neutron-rich Nuclei
14B and 15B ........................................................................

42

The Solar Neutrino Production Reaction 7Be(p, ,)8B Studied
by the Coulomb Dissociation Method ...............................................

43

Interaction Cross Sections and Radii of Mass Number A = 17 Isobars(17N, 17F, and l7Ne) ................................................................

44

Beta-delayed Neutron Decay of 19C and Its Astrophysical Implications. . . . . . . . . . . . . . .

45

The Decay of 14Be ..................................................................

46

Coulomb Dissociation of 11 Be .......................................................

47

Mass Dependence of Pion Production in Heavy Ion Collisions Near
but Below Threshold.. .. .... .. .. .. .. .... ..... .. .................. ........... ........

48

Are All Dripline Nuclei Spherical? ..................................................

49

Experimental Study of the 8He + p Elastic and Inelastic Scattering ..................

50

Observation of lOHe .................................................................

51

Project at GSI "Determination of Neutron Skin Thicknesses for Na Isotopes"

52

Atomic and Solid-State Physics
TheoryCharge Asymmetry of Ionization Cross Sections of Atomic Hydrogenby Antiproton and Proton Impact.................... .. ............. .... .. ..........

53

Double Excitation of H- by Fast Proton and Anti-Proton Impact II.
Spectral Line-profile of an Ejected Electron from 2s2p 1 po Shape Resonance. . . . . . . . .

54

Photodetachment Spectra of H- ....................................................

55

Double Ionization of Helium by Compton Scattering.................................

56

Energy Shift in the Molecules [(ddJL )-d]ee and [( dtJL)-d]ee ...........................

57

Auger Monopole de-Excitation of the Muonic Molecule [(ddJLh,l dee]K,v

58

Experiment
Experimental and Theoretical Study of Multiple Ionization Probabilitiesin 26 MeV Ne4+ + Ne Collisions .... . ...............................................

59

Energetic Electron Production in 20 MeV /u Nq+ and Ta q+

3.

Bombarding Cu and Fe Thin Foils .................... . ................. . .... . ..... .

60

Double and Single Ionization of Helium at Impact Parameter 0 . . ....................

61

Target Ionization in 42 MeV Ar12+ -Ar Collisions ....................................

62

Measurement of Radiative Electron Rearrangement X Rays from
0.8 MeV /amu Ti Ions Excited by Carbon Foil.......................................

63

Binary Encounter Peaks for 0° Electrons in Collisions of Bi q+ ........................

64

Beam-Foil Experiment of Neonlike Iron..............................................

65

Ejected Electron Spectra from 0 4+** (ls2 3131') ........ . ........................ . .....

66

Multiply Charged and Cluster Ions Produced from Gaseous and Frozen
CF 4 under Energetic Heavy Ion Impact .............................................

67

Ions from C60/C70 Fullerenes Deposited on Metallic Foil under
Energetic, Heavy Ion Impact. .. ................. ....................................

68

Muon Catalyzed Fusion in Thin Solid D2 Layer .....................................

69

Resonance Ionization Spectroscopy of Fe ............................................

70

Laser Spectroscopy of Implanted Trace Atoms on a Metal Substrate:
Application of Laser Ablation Ion Trap Method .. . ..................................

71

57Fe Mossbauer Studies of YBa2Cu3.92sFeo.o720s Oriented along the C Axis..... .... .

72

Charge State and Diffusivity of Hydrogenic Atom in GaAs with Si Donors........ .. .

73

Annealing Behaviour of Kr Atoms in Kr-Implanted Aluminium. . ............... . ... .

74

High Energy Heavy Ion Irradiation of Superconductor La2-xSrxCu04

75

Single Event Effect in Power MOSFETs and CMOS ICs by
High-Energy Heavy Ion . . ................................................. . .........

76

Radiochemistry and Nuclear Chemistry

Preparation of a Radioactive Multitracer Solution from Iron Foil Irradiated by
80 MeV/nucleon 16 0 Ions. .. .. ................. .... .................. . .. .. ..........

77

Observation of Complex Formation of a Number of Metal Ions with Tea Extracts....

78

Production of Multitracer Nuclides by Irradiation with a 84Kr Beam. . . . . . . . . . . . . . . . .

79

Transport of Tc(VII) and Re(VII) through a Supported Liquid Membrane80

Determination of Stability Constants of Lanthanide-Humate Complexes
with Multitracer Technique ................................ . ........................

81

4.

Utilization of Multitracer Solutions for Studies on the Ion Exchange
Behavior of a Strongly Acidic Resin NAFION .......................................

82

Adsorption Behavior of Various Elements in Chloride Solutions on ActivatedCarbon Fiber and Non-ionic Macro-reticular Copolymer Using Multitracer ...........

83

Study of the Solvent Extraction of Various Elements with Diphosphine
Dioxide (DPDO) by Use of the Multitracer ..........................................

84

Yield Distributions of Hf Isotopes from the Reactions of Heavy Ions on W Target ....

85

Study on the Nuclear Reactions of 93Nb, 181Ta, and 197 Au Induced bySecondary Neutrons in 40 MeV I nucleon 40 Ar Ion Collisions..........................

86

Limiting Behavior of the Recoil Velocities in the Heavy-Ion Reactions. . . . . . . . . . . . . . . .

87

Dependence of Mass Transfer in the Heavy Ion Reaction on the Mass
Asymmetry at Entrance Channel ............ . ............... . .......................

88

Competition between Fission and Spallation in the Reaction Induced byIntermediate Energy Heavy Ions ....................................................

89

Time-Differential Perturbed-Angular-Correlation (TDPAC) of ,-Rays of
99Ru in YBa2Cu307-x Using 99Rh as a Source Nuclide ............... . ......... . ....

90

Slow Positron Beam Production Using AVF Cyclotron...............................

91

Positronium Formation and Annihilation in Porous Silicon ...........................

92

Heavy Ion Beam Analysis for H-D Isotope Exchange in Glass Surface Layers

93

Radiation Chemistry and Radiation Biology
Time and Depth Resolved Dynamics of Excited States in Ion Trackin Condensed Matter ...............................................................

95

Beam End Point Measurement with Positron Emitting Secondary Beams

96

Initial Recombination in a Parallel Plate Ionization Chamber Exposed
to Heavy-ion Beams ............................................... . ................

97

Ionization Tracks Produced by Ar (95 MeV lu) Ions and their
Core-Penumbra Structure .. . ................................................ . ......

98

Calibration of CR-39 Track Detector for Space Radiobiological Studies and
LET Measurements of Cosmic Ray Nuclei ...........................................

99

Radiation Effects of Ion-particles on Various DNA Structures

100

Studies on Induced Mutations by Ion Beam in Plants
Induced Mutants of Rice Resistant to Bacterial Leaf Blight101

Effect of HZE Particles (Ar, N) on Hatching Rate and Occurrence ofPycnosis of Artemia salina .........................................................

102

Chromosome Aberrations Induced by 135 MeV Carbon and Neon Beams
of RIKEN Ring Cyclotron in Human Blood Cells....................................

103

Molecular Characterization of Mutations in Human Cells Irradiatedwith Carbon Ions....................... ..................................... .......

104

RBEs of Various Human Monolayer Cells Irradiated with Carbon Beams

105

Sensitivity of ts85 Mutant Strain from Mouse FM3A Cells to Heavy Ions

106

5.

6.

IV.

PLD Repair in Tumor Cells after Carbon Beam Irradiation..........................

107

The Early Skin Reaction after Carbon Ion Slit-Beam Irradiation. . . . . . . . . . . . . . . . . . . . .

108

Instrumentation

Computing Environment around the Accelerator Facility

109

A GAL16V8A Programming Equipment.............................................

110

In-beam Mossbauer Spectroscopy in RILAC (1) .....................................

111

Development of Low Energy Unstable Nuclear Beam Channel "SLOW" ..............

112

New Detector System for the First Focal Plane of SMART ..........................

113

Measurement of the Fusion Cross Section of 27 Al + 197 Au Using MWPC andMulti-target System ................................................................

114

First Laser-rf Double Resonance Spectroscopy of Refractory Elements

115

Measurement of Attenuation Length of Scintillation Photons in
Liquid Xenon Due to Heavy Ions.......... ........ .. ... ........................... ..

116

Measurement of Response Functions of Organic Liquid Scintillator
for Neutrons up to 133 MeV ........................................................

117

Test of Inorganic Scintillators Using RIKEN Ring Cyclotron.........................

118

ANew Method of Pulse Shape Discrimination for BaF 2 Scintillators ............ . ....

119

Development of Radiation Monitor in Space.........................................

120

Segmented Germanium Detector

121

Material Analysis

In-situ Analysis of Liquid Samples by PIXE

123

Hydrogen Depth Profile of AI-alloy Vacuum Chamber Exposed toSynchrotron Radiation............ .. .......................... ......................

124

Simultaneous Depth Analysis of Deuterium and Helium in He+ -implanted
YI G Annealed in D2 ................................................................

125

NUCLEAR DATA

Status Report of the Nuclear Data Group127

Production Cross Sections of Radioxenon Isotopes

128

V.

DEVELOPMENT OF ACCELERATOR FACILITIES

1.

Ion Accelerator Development

Status of the RIKEN 10 GHz ECR Ion Source

129

Development of the RIKEN Polarized Ion Source ....................................

130

Basic Study of Polarized He-3 Ion Source for the RIKEN AVF Cyclotron ............

131

Development of a New Type of Single-Bunch Selector ...............................

133

Development of a Beam Phase Monitor with a Micro-Channel Plate .................

135

Development of the Second-Harmonic Buncher for the RILAC .......................

137

2.

VI.

Design of a Variable Frequency RFQ Linac for RILAC ...............................

139

Construction of RIKEN-RAL Muon Research Facility ...............................

141

Theoretical Study of the Relativistic Cyclotron Maser Cooling

142

Synchrotron Radiation Source Development

Correction of Emittance Modulation by Linear Coupling................... ... .... .. .

143

Survey for SPring-8 Storage Ring ...................................................

144

Field Measurements of SPring-8 Dipole Magnets ....................................

145

Field Measurements of SPring-8 Quadrupole Magnets ...............................

146

Construction of Power Supplies for SPring-8 SR Magnet............. .. .. .. .... ......

147

Preliminary Network for SPring-8 Machine Group.............. ... .... ... ...........

149

Measurement of Temperature Dependence of HOM Frequencies
in a Bell-shaped Cavity .............................................................

150

Test of Dummy Loads ..............................................................

151

Test of 1.2 MW Circulator ..........................................................

153

A Phase Lock System of 508.58 MHz Reference Line ................................

155

A Direct Counter of 508.58 MHz ....................................................

157

Transmission Test of the Timing Signal for the SPring-8 .............................

158

Control of SPring-8 SR Klystron Test Bench ........................................

160

Performance Test of Energy Analyzer for Photoelectrons Produced
by SR Irradiation ...................................................................

161

Outgassing Rate Measurement of Braided Wire .....................................

163

Design of Beam Position Feedback Systems for SPring-8 Storage Ring

164

RADIATION MONITORING

Measurement of Activities Induced by 135 Me V lu 20Ne Incident on an
Iron Target with the Activation Method. .. ...... ....... ........... .. ...... ...... ....

165,-ray Spectrum from Iron Targets Bombarded by Accerelated Ions.. .. .. .. ....... ....

166

Shielding Effect of the Concrete Wall between E1 and E2 Rooms ....................

167

Leakage Radiation Measurements in the Ring Cyclotron Facility. ..... .. ...... .. .. .. .

168

Residual Activities in the Ring Cyclotron Facility . .. ................................

169

VII.

LIST OF PUBLICATIONS ............................................................... 171

VIII.

LIST OF PREPRINTS ................................................................... 176

IX.

PAPERS PRESENTED AT MEETINGS .................................................. 178

X.

LIST OF SyMPOSiA .................................................................... 187

XI.

LIST OF SEMINARS

188

XII.

LIST OF PERSONNEL

190

AUTHOR INDEX

I. PREFACE

This report illustrates research activities at the
RIKEN Accelerator Research Facility for the year of
1993. The research program has been coordinated in
the framework of the project entitled Multidisciplinary
Researches on Heavy Ion Science. It covers a varietyof research fields; nuclear physics, atomic physics, nuclear chemistry, radiation biology, condensed matterphysics in terms of accelerator or radiation, basic studies on energy production, basic studies on accelerator
cancer therapy, material characterization, application
to space science, accelerator engineering, laser technology and computational technology.
The major facility involved is the RIKEN Ring Cyclotron (RRC) which is a K = 540 separate-sector cyclotron providing intermediate-energy heavy ions overa broad range of elements. Two injector accelerators,i.e., an energy-variable heavy ion linear accelerator(RILAC) and a K = 70 AVF cyclotron, are alternatively operational in a stand-alone mode. The accelerators were constructed in series and the whole complex
has been operational since 1988. In addition there exists a 1.5 UD Tandetron, which has been renewed thisyear. For this year the RRC alone has delivered thebeam time (on the target) of about 5000 hours.
The research program is carried out by researchers
from 14 RIKEN laboratories among about 50 in total. A large number of outside researchers and students from universities or other research institutions
have also participated in our activities. Domestically the number of the participants amounts to about
300, while international collaboration is extended overabout 30 institutions. Besides the activities at homeinternational cooperative programs located at foreign
facilities are being undertaken. A major program atpresent is on muon science, for which installation ofa muon beam facility is in progress at RutherfordAppleton Laboratory.
The heavy ion research program at the Facility has
enjoyed another year of steady development. A special emphasis at RRC has been continuously placed on
the development and application of a variety of types ofradioactive isotope beams (RIB): Firstly intermediateenergy RIB by means of the projectile fragmentation(PF) have been most frequently used by accounting
for about 40% of the whole RRC beam time. To ease
the heavy interference among the experimental setups
a beam distributing magnet to switch beams into threedifferent channels has been newly installed. The beams
have been useful particularly for studies on neutronrich nuclei and nuclear astrophysics: lOHe has been
identified; structure and dynamics of neutron halos orskins have been studied in terms of Coulomb dissoci-ation and direct nuclear reaction processes; Coulomb
excitation of 32Mg has been observed; delayed neutron
spectroscopy has been initiated, a study on sub-barrier
fusion reactions involving extremely neutron-rich nuclei is in progress; and finally the Coulomb dissociation
cross section of 8 B has been successfully measured inrelation to the solar neutrino problem.
The second type of RIB is the spin-polarized beam
which is also produced via the PF process covering awide range of nuclear species. The beam has been primarily used to determine nuclear moments of unstable
nuclei including exotic nuclei such as 17B. The third
type of RIB is the high-spin isomer beam which is produced via a reverse-kinematics fusion reaction. Beamsof heavy isomers with spins close to 30 h are obtainedwith considerable intensities. In an attempt to reachextremely high spin states the beams have been applied to Coulomb excitation to populate states on topof the isomeric states.
Heavy unstable nuclei have also been studied using a
gas-filled type recoil separator (GARIS). Here a major
program aims at developing a new scheme of synthesizing very heavy elements. A method in terms of (Heavy
ion, axn) reactions has been tested. So far an encouraging indication has been obtained for the synthesis of
an isotope in the region of Z = 108. It has been realized that the separator is also powerful for the studyof other trans-uranium isotopes and a related project
has been initiated.
In the context of nuclear physics spin-isospin response is another major subject, where reactions(d,2He) and (d,d(O+)) are primarily concerned. The
main apparatus for this research is a high-resolution
particle analyzer (SMART) which has a Q-Q-D-D
magnetic configuration with wide angular and momentum acceptance. A spin-polarized ion source for
deuteron has been also developed, which has so far
achieved a beam intensity of about 100 J-LA at thesource exit. The spin-isospin response has been as wellstudied via heavy-ion exchange reactions. These reactions at high energies have been proved to provide
useful spectroscopic probes.
The heavy ion research activities have covered a variety of domains beside nuclear physics. Among themstudies on atomic physics have been pursued, enjoying
an extremely wide energy range of heavy ions provided
by the ECR ion source, RILAC and RRC. Ionization
processes in hard collisions between heavy ions andatoms are studied by measuring slow recoil ions andfast electron ejectiles. Beam foil spectroscopy of highly
charged heavy ions in the region of VUV photons has
been extended to Fe and Nb ions. Basic information1

for laser and plasma applications is gained.
In the field of nuclear chemistry significant development has continued on the methodology of multitracer. Formula using different target and projectile
combinations at RRC have been newly established toprepare mixtures of a variety of radioactive isotopes.
Sets of multi-tracers thus obtained have been extensively utilized for chemical, environmental and biological systems to trace the circulation behavior of different elements simultaneously. For instance studies onrats have been started. Radioactive isotopes are as wellused for other methodologies such as Mossbauer spectroscopy and TDPAC, which are applied to high-Tc
superconductors and magnetic materials. On the other
hand in-beam Mossbauer spectroscopy using Coulomb
excited 5 7 Fe is in progress at RILAC.
Heavy ion beams have offered a variety of means
for material characterization such as PIXE, Rutherford
scattering and channeling effects. Recently a projecton slow positron spectroscopy using short lived isotopes was started at the AVF cyclotron. Heavy-ion
beams are also useful to improve the property of material. In this context a new project on high-Tc superconducting materials has been started. It has beenfound that the critical current density increases significantly after irradiation of high-energy Xe ions.
Studies on irradiation effects with heavy-ion beams
are directed to two major fields. One is the domainof radiation biology. Effects of high LET are studied for a variety of biological samples. In particular
the study on DNA damages is continued by incorporating mutation analysis. Basic studies for heavy-ionbeam cancer therapy are carried out in collaboration

with National Institute of Radiological Science. Studies of curing probability are extensively performed withtumor-bearing mice. Recently an intriguing application of radioactive beam was tested in relation to thecancer therapy. Use of a radioactive beam may offer apossibility to gain real-time information on the rangeof the ions shooting the body, where the location of the
stopped isotopes may be spotted by means of positron
tomography. A simulation experiment using a radioactive beam of llC was performed, demonstrating an encouraging perspective.
Another important domain on irradiation effects
concerns the space technology. High-energy heavy ionsfrom RRC serve as a good simulator of cosmic rays inspace. Thus a broad range of samples, including detectors and biological samples are irradiated to study
characteristic damages. In particular studies on electronic devices are made in collaboration with National
Space Development Agency of Japan.
Concerning the muon program the primary effort
has been made to complete a muon beam facility at the
proton synchrotron ISIS of the Rutherford-Appleton
Laboratory. It is expected to be finished in 1994. At
home the production of negative muon beams is studied using high-energy heavy ions.
In summary the year of 1993 has marked a steadyand continuous development of the Facility. In viewof the ever growing demands for the Facility we havestarted an intensive study for a next-generation accelerator to be installed at the Facility. A broader use ofradioactive beams will be pursued. An energy booster
in terms of super-conducting separate-sector cyclotron
is considered as a possible candidate.

Masayasu Ishihara
Director
RIKEN Accelerator Research Facility

2

II.. OPERATION OF ACCELERATORSRIKEN Accel. Prog. Rep. 27 (1993)

RRC Operation
A. Goto, M. Kase, N. Inabe, T. Kageyama, I. Yokoyama, M. Nagase, S. Kohara, T. Nakagawa, K. Ikegami,
O . Kamigaito, J. Fujita, H. Isshiki,* H. Akagi ,* R. Ichikawa,* N. Tsukiori ,* R. Abe,*K. Takahashi,* S. Otsuka,* T. Maie,* T . Kawama,* T. Honma,* and Y. Yano
accelerated 21 MeV/nucleon 181Ta ions, which are theheaviest ever accelerated with RRC. Figure 1 shows
the plots of the ions accelerated so far in the available
region of energy-mass space.
Regular long-term overhauls were carried out for 3
weeks in the winter and for 6 weeks in the summer.
In the summer overhaul, the following irregular maintenace was made: replacement of the MDC2 with a
new one, shift of the phase probe assembly upward by
5 mm, and replacement of the slide-contacts for the
movable short of the 3 k W rebuncher resonator. The
shift of the phase probe assembly was made because we
had such a trouble that in April and May the upper
electrodes of the two outermost phase probes got out ofplace due to melt-down of their supports hit by beams.

Table 1 lists the ions that were served to users from
November 1992 to October 1993. We delivered 24
kinds of ion species for the last one year in a total beamtime of 184 days. Of those days, the AVF-RRC operation was performed for 143 days (78%) and the RILACRRC operation for 40 days (22%). The beam time of
135.5 days (74%) was devoted to nuclear physics experiments and that of 48.5 days (26%) to non-nuclear
physics experiments. Experiments using secondary
beams with RIPS (68.5 days) and biological irradiation
experiments (31.5 days ) have the majority in nuclear
physics and non-nuclear physics study, respectively.
The AVF-RRC complex has been able to routinely provide, e.g. , over 200 pnA of 135 MeV/nucleon light ionsand over 60 pnA of 95 MeV /nucleon 40Ar ions. We

Table 1. RRC beams accelerated during November 1992 - October 1993.

Particle

H2
d
pol.d
llB

12C
13C
14N
160
180
2~e

22Ne
4°Ar

58 Ni
84Kr
136Xe
18 1TaCharge

1
1
1
1
1
5
6
6
4
7
8
8
8
10
10
5
14
14
14,15
17
9
13
23
37

RFF
(MHz)

h

24.6
32.6
24.6
32.6
32.6
24.6
32.6
24.6
25.4
32.6
26.2
24.6
29.0
32.6
30.1
18.0
30.0
33.0
34.4
28.1
19.5
20.0
18.6
25.4

5
5
5
5
5
5
5
5
9
5
5
5
5
5
5
11
9
9
9
5
10
10
10
9

Injector

AVF
AVF
AVF
AVF
AVF
AVF
AVF
AVF
RILAC

AVF
AVF
AVF
AVF
AVF
AVF
RILAC
RILAC
RILAC
RlLAC

AVF
RlLAC
RILAC
RlLAC
RlLAC

Energy(MeV /nucleon)

Beam time

70
135
70
135
135
70t
135
70t
21t
135
80
70
100
135
1l0t
7t
30
37
40t
95
lOt
10.5
9t
21t

2.5
4.5
6
11
3.5
28
5.5
1.5
1.5
5
9
32.5
10
8.5
3.5
4
3.5
4.5
12.5
3
5.5

Total

184

(days)

3

11.5
4

t New beams*

Sumijyu Accelerator Service, Ltd.

3

200

•

Ions Accelerated(Apr. 1987 - Oct. 1993)

150

A VF Injection

Linac Injection
50

10
0

I

••• •
• ••

•

••
•Ne

N AIC. Cu

HCO,", Ar Zn Kr

Xe

Er

T.

Bi U

Atomic Mass

Fig_ 1. RRC beams accelerated during April 1987October 1993.
We had the following big machine troubles in September after the summer-overhaul period: the newly installed MDC2 was found to be mis-manufactured forthe production of magnetic field and had to be repaired, the final RF amplifier of the RRC stopped operating four times due to the trouble of cooling water
for the plate electrode, and the power-feed part of the
3 kW rebuncher resonator was burnt. Because of thosetroubles, 11 days of the scheduled machine time had
to be cancelled.
This year, several R&D's have been made: installation of a second-harmonic buncher on the injection
beam line of the RILAC ,l) development of a new beam
detector with a micro-channel plate (MCP),2) development of a single-bunch selector for use on the injection beam line of the AVF cyclotron,3) and installation of an ExB spin rotator immediately downstreamof the polarized p/d ion source. 4 ) By the installationof the second-harmonic buncher next to the existing
fundamental-frequency buncher, the output beam intensities from the RILAC have been improved by afactor of 1.5, and those from the RRC by a factor of
2- 3. Time structures of the AVF cyclotron and RRC

4beams were measured with the new beam detector.
The detector has been found to work not only as aphase monitor for stabilizing the magnetic fields of thecyclotrons, but also as a monitor for single-turn extraction or a measuring instrument of turn number inside
the cyclotrons. The single-bunch selector is very compact and cost-saving because it is operated in the low
energy section before the AVF cyclotron. It was used
for a calibration experiment of a neutron counter with
135 MeV/nucleon Ht beam. We plan to increase therepetition rate from 20 kHz up to as high as 1 MHz
using a higher-speed semi-conductor device. The installation of the spin rotator, taking advantage of thesingle turn extraction available for both the AVF cyclotron and the RRC, has allowed us to freely control
the spin direction of polarized deuterons without reducing the polarization or the intensity.
Design of a new injector system of the RILAC has
also progressed, aiming to increase beam intensitiesof heavy ions by one or two orders of magnitude. It
consists of a single-stage high-field 18 GHz ECR ion
source 5 ) and a variable-frequency RFQ linac. 6 ) Bothof them have already been preliminarily designed. The
RFQ linac is characteristic of its "folded coaxial" structure, which has the advantages of t he compactness ofthe cavity even for the low frequency and the wide
frequency-tunable range of the cavity. A half-scaled
model for the cold test of t he cavity is now under fabrication for completion by the end of this year.
Stand-alone use of the AVF cyclotron, which is madewhile the RRC is operated with the RILAC beam injection, started in June of this year. The total beamtime was 8 days. For the details, see Ref. 7.

References
1) S. Kohara et al.: This report, p. 137.
2) M. Kase et al.: Proc. 9th Symp. on Accel. Sci. andTechnol. , Tsukuba, p. 474 (1993).
3) N. Inabe et al. : This report, p. 133.
4) H. Okamura et al. : This report, p. 130.
5) T . Nakagawa et al.: Proc. 9th Symp. on Accel. Sci. andTechnol. , Tsukuba, p. 98 (1993).
6) O. Kamigaito et al.: This report, p. 139.
7) A. Goto et al.: This report, p. 6.

RIKEN Accel. Prog. Rep. 27 (1993)

RILAC Operation
E. Ikezawa, M. Hemmi, T. Chiba, Y. Chiba, T. Aihara,* T. Ohki,*
H. Hasebe,* H. Yamauchi,* M. Kase, M. Yanokura, and Y. Miyazawa
RILAC has been in steady operation, and has supplied various kinds of ion beams for experiments. Table
1 gives the statistics of operation from Jan. throughDec. 1993. Table 2 summarizes the time sharing for individual research groups. The percentage of the beamtime for RIKEN Ring Cyclotron (RRC) was about
41 %; ions of 14N, 36 Ar, 40 Ar, 58Ni, 84Kr, 136Xe, andI8ITa accelerated by RILAC were injected to RRC.
Table 3 gives the statistics of ions used this year. We
began accelerating B3+, Ga l l +, and Nb 12 + at the frequencies of 35, 30, and 32 MHz respectively. The beamtime for metallic ions amounted to about 22%.

Table 3. List of ions used in this year.
Ion
He
B
C
N
N
0
Ne
Ar
Ar
Ca
Fe
Ni
Ga
Kr
Nb
Mo
Xe
Ta
Bi

Table 1. Statistics of the operation from Jan. 1 throughDec. 31, 1993.

Beam time
Frequency change
Overhaul and improvement
Periodic inspection and repair
Machine trouble
Scheduled shut down
Total

Day
170
20
33
27
2
113
365

%
46.6
5.5
9.0
7.4
0.5
31.0
100

Table 2. Beam time for individual research groups.

Atomic physics
Solid-state physics
Nuclear chemistry
Radiation chemistry
Accelerator research
Beam transportation to RRC
Total

Day
41
12
19
13
16
69
170

%
24.1
7.1
11.2
7.6
9.4
40.6
100

Cancellation of the scheduled beam time due to machine troubles in RILAC totalled two days; one day due
to a vacuum leak at a gate valve of the beam transport line and the other due to the end of life of the final
vacuum tube which was used for the last thirteen years
in the RF system of No.1 resonator. Another threedays of beam time were abandoned owing to trouble
in RRC and another day in user side.
We carried out the following items in this year.
Preventative maintenance: 1) Because of deterioration of the optical fiber cables transmitting control signals to the injector high voltage station, the cables used
for eight years were replaced with new ones. 2) The
power supplies for the drift tube magnets used in the*

Sumijyu Accelerator Service, Ltd.

Mass
4
11
12
14
15
16
20
36
40
40
56
58
69
84
93
98
136
181
209

Charge state
1
3
2
3, 4
3
2
4
5, 6
4,5,6,8
6, 7
6
9
11

11,13
12
11
9, 15, 16
16
16

Day
10
1
2
6
1
2
2
6
58
3
13
5
2
12
6
1
33
4
3

resonators No.1 and 3 were remodeled by replacing
the obsolete power transistors with the modern ones.
3) Three water pumps for the cooling tower water circuit, the ordinary water circuit, and the deionized water circuit were overhauled.
Improvement: 1) A carbon foils exchanger installedat the exit of No.6 resonator was replaced with a newone; this unit can mount 40 carbon foils. 2) To feedenriched gas such as 36Ar and I36Xe in the ion source
we installed two more reservoirs. There are two feed~
ing systems, each has two reservoirs. 3) In an electrostatic quadrupole lens installed at the beam exit of
the ECR source, the surface insulation of high voltage
connectors was deteriorated with sputtered metals; theshields from sputtering were fortified.
Development: 1) A second-harmonic buncher was
installed in the injection beam line in this March. I )Using both the fundamental-frequency and the secondharmonic bunchers, we got about 50% increase of beam
intensity at the exit of RILAC compared to that with
only the former. 2) We have tested to obtain metallicions by use of a material such as BN, LiF, and Ga203'
Ion currents with these compound rods except the BNcase were very stable. At present we can supply ionsof 10 gaseous and 37 solid elements.

References
1) S. Kohara et al.: This report, p. 137.

5

RIKEN Accel. Prog. Rep. 27 (1993)

AVF Cyclotron Operation
A. Goto, T. Kageyama, M. Kase, S. Kohara, M. Nagase, T. Nakagawa, K. Ikegami, O. Kamigaito,
N. Inabe, 1. Yokoyama, J. Fujita, H. Isshiki,* H. Akagi,* R. Ichikawa,* N. Tsukiori,*
R. Abe,* K. Takahashi,* S. Otsuka,* T. Maie,* T. Kawama,* T. Honma,* and Y. Yano
Table 1 lists the ions accelerated by the AVF cyclotron in the past four years since the first beam was
obtained. We have accelerated 16 kinds of ion species.
Beam intensities of several eJ-LA are routinely extracted
in recent operation. The total beam time for the last
one year was 143 days. The beam times for the following three kinds of ions exceeded 50% of the total beamtime: 5.2 MeV jnucleon (95 MeV jnucleon from theRRC) 40 Arll+ and 7 MeV jnucleon (135 MeV jnucleon)
12C4+ and 18 0 6 +.
The beam extraction efficiency of over 75% (themaximum record is 90%) is routinely obtained. The
beam transmission efficiency through the cyclotron isthen typically about 20%, though it depends on thekind of accelerated ion and in some cases drops as low
as about 5%. A single turn extraction can be achievedby carefully adjusting the first harmonic field near the
extraction and the currents of the trim coils near the
cyclotron center. One of the advantages of the single
turn extraction available for both the AVF cyclotron
and the RRC is that it allows us to freely control the
spin direction of a polarized beam using an ExB spinrotator (a Wien filter) placed downstream of the polarized ion source, without reducing the polarizationor the intensity.

Pulse width of the extracted beam was preliminarily
measured with a new type of beam phase monitor.1)
The width (FWHM) of 5.5 MeV jnucleon 18 0 6 + ion
beam was 1.6 nsec corresponding to 8.4 RF degrees.
Precise measurement with the monitor will be made.
A single-bunch selector has been successfully
developed. 2) It is very compact and cost-saving because it is operated on the beam transport line between the ECR ion source and the AVF cyclotron. Performance study of the single-bunch selector was carried out for the 7.45 keV Ht beam from the ECR ion
source (the beam energy from the AVF cyclotron was
7 MeV jnucleon) . The time spectrum obtained withthe above beam phase monitor located immediately after the cyclotron showed that almost complete singlebunch selection was achieved. The repetition rate of
the selector is now as low as 20 kHz. We plan to increase the repetition rate up to as high as 1 MHz using
a higher-speed semi-conductor device.
This year, there have been serious troubles with respect to the following cyclotron components: a partof the RF slide-contacts of the movable shorting plate
was burnt and melt; and the deflector became not towork due to its unendurable leak current. In the latter
case, powder-like stuff containing very thin and short

Table 1. Ions accelerated with the AVF cyclotron during April 1989 - October 1993.
Particle Charge RFfreq.

Energy*Intensity(MHz) (MeV/nucleon) (e~)
p
H2

d

pol.d
lIB

12c
13C

1
3
4
4
4
4

19.35
21.1
12.3
14.0
16.3
12.3
13.8
14.5
16.0
16.3
16.3
12.3
13.95
14.5
16.3
12.3

9.9 (210)
11.8 (270)
4.0 ( 70)
5.2
7.0 (135)
4.0 ( 70)
5.0
5.5 (100)
6.7 (130)
7.0 (135)
7.0 (135)
4.0 ( 70)
5.1 (92)
5.5 (100)
7.0 (135)
4.0 ( 70)

5.2
0.07
3.1
5.0
5.4
1.4
2.6
0.6
0.5
3.4
0.3
1.0
0.7
0.6
7.3
2.0

Particle Charge RF freq.
Energy·Intensity(MHz) (MeV/nucleon) (e~)
14N
15N
160
180

2~e

22Ne
24Mg
27Al
4°Ar

4
5
4
5
5
6
5
6
7
6
7
7
8
9
11
11

13.0
16.3
12.3
15.25
13.1
16.3
12.3
14.5
16.3
12.3
15.05
14.5
14.5
16.0
13.0
14.05

4.4 ( 80)
7.0 (135)
4.0 ( 70)
6.1 (115)
4.4 ( 80)
7.0 (135)
4.0 ( 70)
5.5 (100)
7.0 (135)
4.0 ( 70)
6.0 ( 110)
5.5 (100)
5.5 (100)
6.7
4.4 ( 80)
5.2 ( 95)

• The values in the parentheses show the energies obtained by the coupled operation with the RRC.

*
6

Sumijyu Accelerator Service, Ltd.

3.3
12.0
2.6
1.3
7.8
3.3
5.2
12.0
7.4
5.9
1.7
2.1
0.3
0.5
0.4
4.6

needle-like stuff adhered to the surfaces of the septum
and the electrode along the median plane level. To re-

From ECRIS I PIS

move the origin-unknown stuff, we had to disassemble
the cyclotron five times during the past one year.
Stand-alone use of the AVF cyclotron started in Juneof this year. For this use three experimental ports havebeen provided as shown in Fig. 1: at port A is installeda chamber for use in radioisotope production; at port
B a scattering chamber for slow-positron experiments;
at port C a scattering chamber for nuclear physics experiments. The port A is located at the end of theextraction straight line in the cyclotron vault, the port
B at the end of the vertical line in E7 experimentalroom and the port C at the end of the horizontal linein E7. So far two experiments were made in a total
beam time of 8 days: production test of slow-positrons
using 5.2, 7 and 9.9 MeV/nucleon proton beams at theport B3) for 3.5 days and measurement of fusion crosssections using 6. 7 MeV/nucleon 27 Al beam at the port
C for 4.5 days. The stand-alone use is made while theRRC is operated with the RILAC beam injection.

From RRC

Fig. 1. Schematic drawing of the arrangement of experimental ports A- C in the AVF cyclotron vault and E7
experimental room. Port A: Radioisotope production;
Port B: Slow-positron experiment; and Port C: Nuclear
physics experiment.

References
1) M. Kase et al.: Proc. 9th Symp. on Accel. Sci. andTechnol., Tsukuba, p. 474 (1993).
2) N. Inabe et al.: This report, p. 133.
3) Y. Itoh et al.: This report, p. 91.

7

RIKEN Accel. Prog. Rep. 27 (1993)

Tandetron Operation
E. Yagi, T. Urai, and M. Iwaki
The Tandetron was operated for 60 days for experiments in the period from Nov. 1, 1992 to Oct. 31,
1993. In this period the beam time allotted to experiments was much reduced because of various troubles
in the duoplasmatron ion source and the electric power
supply for the switching magnet.
The experimental studies on the following subjects
were made.
(1) Rutherford backscattering spectroscopy (RBS)(a) Behaviour of Kr atoms implanted into aluminium by a channelling method (Metal Physics Lab.).
(b) Behaviour o.f Xe atoms implanted in iron (Metal
Physics Lab.).
(c) Analysis of radiation damage in a Tb- and Euimplanted CaF 2 (Semiconductor Lab. and Surface
Characterization Center).

8(d) Silicide formation in Ni-deposited silicon (Metal
Physics Lab.).
(e) Characterization of Ni films grown on MgO by
biased dc sputter deposition (Metal Physics Lab.).
(2) Radiation effects(a) Radiation damage of diamond (Earth SciencesLab.).
(3) Nuclear reaction analysis(a) Lattice location of hydrogen in niobium alloys
by a channelling method (Metal Physics Lab.).
(4) Particle induced X-ray emission(a) Application of PIXE to biomedical and material sciences: Trace element analysis using energydispersive X-ray spectrometry, and chemical state
analysis using wave-dispersive X-ray spectrometry (Inorganic Chemical Physics Lab.).

III.

RESEARCH ACTIVITIES1. Nuclear Physics

RIKEN Accel. Prog. Rep. 27 (1993)

Reaction Cross Sections of Light Isobars (Ain the Glauber Model

17)

H. Kitagawa, A. Ozawa, and 1. Tanihata[Glauber model, A = 17 isobars.]
Measurement of reaction cross sections of A = 17
isobars (17Ne, 17F, 17N, 17B) at LBL (incident energy
is 790 MeV lu)l) revealed an anomaly in 17Ne and 17B.
The measured cross sections of 17Ne and 17B are fairly
larger than those of other isobars.
By considering the separation energies, we find thatthe structure of 17Ne is similar to that of 11 Li. Two
proton separation energy of 17Ne is very small, 0.954
MeV, whereas one proton separation energy is larger
than it, 1.489 MeV. Two neutron separation energyof 11 Li is 0 .197 MeV, and one neutron separation energy is 1.001 MeV. We consider that 17Ne may be a
candidate of a "proton-halo" nucleus.
We calculate the reaction cross sections of 17Ne, 17F,
17 0 and 17N where the targets are 9Be, 12C and 27 Al
respectively. We do not consider 17B, because there isno data of 17Na, the mirror partner of 17B.
Density distributions are calculated by the SkyrmeHartree-Fock (HF) method with the SGn interaction
except for 17Ne. Considering the structure of 17Ne
stated above as a system of 15 0 core and the two valence protons, the wave function of the valence proton is obtained from the Woods-Saxon potential whose
separation energy is fitted to be a half of two proton
separation energy, i.e. 0.954 MeV12. We make the17Ne density distribution by adding twice the densityof the valence proton in the 1d5/ 2 orbit to that of the
15 0 core which is obtained by the Skyrme-HF. We do
not consider for simplicity the paring effect of the twovalence protons, which play an important role to become a "halo" nuclei. The density distribution of 17Ne
is shown in Fig. 1.
We employ the Glauber model to calculate the reaction cross section from the density distribution ofboth projectile and target. The reaction cross section
is calculated by the following equation,

100

O'R = 211'

T(b) = exp(1 - T(b)) b db[-q Jdr JPT(r)dz Jpp (lr' - bl) dz']
1.

10-3

"

,

" " ,"!Ie proton

10

16

20

r(fm)

Fig. l. Density distribution of 17Ne is shown. The area
between the 15 0 proton and the 17Ne proton shows thecontribution of the two valence protons of 17Ne.

incident energy, 790 MeV lu.
Results of calculations of the 12C-target case areshown in Fig. 2. For comparison we also show theresults with the shell model-harmonic oscillator wave
functions. We can see that the cross section of 17Ne
increases by including roughly the effect of the spatial
expansion of the valence proton wave function due tothe small separation energy.
o

I

I

I

target: 12C

1160 I--..... • hell model1100 r-- -o:0 1060 l-

E.

~ 1000 r-

Hortree-Fock

clato

-

-

950 -

900 -217Ne

I-1Fig. 2. Reaction cross section of A = 17 isobars at
E inc =790 MeV lu is shown. The target is 17C. Dottedand dashed lines are the results of calculations of theshell model and the Hartree-Fock respectively. Squares
are the observed values (Errors are not shown here).

1

q = ATAp «ZTZp + NTNz ) O'pp

+ (ZTN p + NTZp)u np )where N p , Zp, A p , and pp are the neutron, proton,mass numbers and the total density of the projectile,
respectively, and r' = (x, y, z') and b = (b, 0, 0).
The effect of the Pauli blocking 2) and the effect ofbending the path due to the Coulomb force are included, but they contribute only 1% at most at this

Although the dependence on the isospin is qualitatively
reproduced, the observed value of 17Ne is not reproduced. If this rough estimation is reliable, we might beable to say that this discrepancy suggests an anomaly
in 17Ne such as a "proton-halo".
References
1) A. Ozawa et al.: RIKEN preprint, Nov. (1993).
2) H. Kitagawa: RCNP annual report, p. 95 (1992).

9

RIKEN Accel. Prog. Rep. 27 (1993)

Multistep Process in the 14 0 Dissociation Reaction
T. Motobayashi[208Pbe 40,13N p )208Pb; Coulomb dissociation, coupled channel analysis.]
The Coulomb dissociation process can be a tool tostudy radiative capture processes exciting unboundstates of astrophysical interest. This is based on theidea that the process is due to the absorption of avirtual photon and hence can simulate the photoabsorption process, the inverse reaction of the radiative
capture. 1) The photoabsorption cross section is deduced by dividing the dissociation cross section by thevirtual photon intensity, if one-step reaction mechanism is assumed.
A possible influence of the multistep Coulomb excitation on the results obtained for the 208Pbe 4 0 ,13 Np)208Pb reaction has been discussed by Delbar. 2) This
reaction is related to the 13N(p,I')140 reaction, a key
reaction igniting the hot-CNO cycle breaking out fromthe regular CNO cycle of hydrogen burning in massive stars. The process via the 1- resonant state at
Eex = 5.17 MeV in 14 0 almost determines the astrophysical reaction rate, and therefore the radiative
width r, of this 1- state is of crucial importance. Our
Coulomb breakup experiment at E in = 87.5 MeV at
RIKEN reports r
3.1 ± 0.6 eV. 3) A direct measurement of 13N(p,I')140 at Louvain La Neuve using a 13N
beam4) gave a similar result r
3.8 ± 1.2 eV. Delbar argues in Ref. 2 that the excitation of the second
two-step0+ state at Eex = 5. 92 MeV via the 0+ -1 process affects the 0+ -1 - dissociation cross section. He
gave an upper limit of the two-step contribution, whichchanges the value of r, from 3.1 eV obtained by Ref. 3
to 5.5 eV. He also proposed a possible explaination forthe yield experimentally observed at a higher excitation energy of 14 0 by this two-step Coulomb excitation
to thestate.
The aim of the present report is to clarify the roleof the multistep excitation mechanisms played in the
breakup process 208Pbe 4 0, 13 N p)208Pb. A coupledchannel calculation was performed by taking into account the ground state and four excited states, 1- at
5.17 MeV,
at 5.92 MeV, 3- at 6.27 MeV and 2+ at
6.59 MeV of 14 0 shown in Fig. 1. No experimental information is available for the transitions among them,
except for the 0+-1 - excitation. Some analogue transitions are known for 14C, and they were used in thepresent calculation assuming the isospin symmetry.
An example of the results is shown in Fig. 2 for the

=====
_

t

.",o.sti:4cs - - - - - - - - - - -

6.27
6.59
5.92
5.17

32+
0+
1-

"
0+

Fig_ 1. Low lying states of 140.

10000

14 0 DISSOCIATION

,=

,=

-ot

ot

ot

10

Fig. 2. Predictions of the coupled channel calculation
for the reaction 20Bpbe 4 0, 13 N p)20Bpb exciting the l andstates in 14 0.

otcase discussed by Delbar,2) where the three states, 0+,
1- andare taken into account. As seen in the figure, the two-step excitation to the second 0+ state isvery week and its effect is hardly seen in the 1- excitation cross section. Therefore the multistep excitation is not likely to affect the 208Pbe 40,13N p )208Pb
Coulomb dissociation result. The situation does notchange when all the states in Fig. 1 are taken into account. The same coupled channel calculation suggeststhat the yield at above the 1- state is due to the onestep nuclear excitation to the 2+ and 3- states.

ot,

References
1) G. Baur, C. A. Bertulani, and H. Rebel: Nucl. Phys.,A458, 188 (1986).
2) Th. Delbar: Phys. Rev., C47, R14 (1993).
3) T. Motobayashi et al.: Phys. Lett., B264, 259 (1991).
4) P. Decrock et al.: Phys. Rev. Lett., 67, 808 (1991).

RIKEN Accel. Prog. Rep. 27 (1993)

El Giant Resonance in 220
M. Tohyama[unstable nuclei, giant resonances, time-dependent density-matrix theory.]
We study the E1 giant resonance in 220 as an example to understand the response of very neutronrich nuclei to external fields. We use a microscopic
model called the time-dependent density-matrix theory (TDDM) which is a straight forward extension of
the time-dependent Hartree-Fock (TDHF) theory so
as to include the effects of nucleon-nucleon collisions.
TDDM has been applied to the decay of giant resonances at zero 1 ) and finite temperatures 2 ) and to themass fluctuations in low-energy heavy-ion collisions 3 )and found to give reasonable dissipation-fluctuation
properties. The E1 strength functions obtained areshown in Fig. 1. The TDHF strength function consists of two well separated components. One is thebump above 20 MeV and the other is the peaks seen
below 15 MeV. The former may be associated with acore excitation mode because a similar bump is seenin the E1 strength function of 16 0. The latter is considered to originate in the excitation of the excess neutrons since there are no corresponding peaks in 16 0.
The sharp peak at 20.4 MeV seen in the TDHF result is completely damped in TDDM and the TDDM
strength distribution below 20 MeV becomes structureless. The strength distribution around 25 MeV
and above, however, is not affected by the inclusionof two-body correlations. The effects of two-body

1.0
0.8

;,
Q)

::E

0.6

'"

S 0.4

GJ
r;:; 0.2
0.0
5

10

15

20

25

30

35

E [MeV]

Fig. 1. E1 strength distributions in 220 calculated in
TD HF (dotted curve) and TD D M (solid curve).

correlations on the E1 mode in 220 are quite different
from those in closed shell nuclei like 16 0 and 40Ca,
where the E1 strength distributions are not seriously
affected by two-body correlations. 2 )References
1) M. Gong and M. Tohyama: Z. Phys., A335, 153 (1990).
2) F. De Blasio et al.: Phys. Rev. Lett., 68, 1663 (1992).
3) M. Gong et al.: Z. Phys., A335, 331 (1990).

11

RIKEN Accel. Prog. Rep. 27 (1993)

Isoscalar Monopole Vibrations around Thermal Equilibrium
S. Yamaji, H. Hofmann,* and A. S. Jensen**[Large scale collective motion, giant resonance, linear response theory.]
Dynamics of heated nuclei attracts a lot of attention because it is experimentally accessible and exhibits interesting features for systems of a finite number of particles both of quantal and statistical properties as well as the interplay between collective andsingle particle degrees of freedom. Commonly theoretical studies concentrate on thermodynamical featuresin the proper sense, such as the free energy, entropy or
nuclear density. These quantities characterize static
situations. Here, we want to discuss the temperature dependence of dynamical properties like positions
and widths of specific excitations and their relative
strength. Our approach 1 ) differs in two essential ways
from the tranditional Hartree-Fock and RPA descriptions. First, the effective coupling constant depends
both on deformation and on nuclear excitation energy.
Secondly, we account for the temperature dependent
additional incoherent coupling to residual degrees of
freedom. The possible collective excitations may be
parametrized conveniently in terms of the collective
response function Xcoll. For one degree of freedom one
obtains, by use of the assumption of proportionality
between average potential and density variations
X(w)Xcoll(W) = 1 + kX(w)(1 )w here X(w) is the intrinsic response function and 1I k
is the coupling constant. The latter is given as,(2)
where f is the free energy, X(w = 0) is the static response and Qo is the equilibrium value of the collective
coordinate Q which parametrizes the variation of theaverage potential. Both f and X and therefore also
11k, depend on the temperature. We calculated thecollective response function (1) for the typical isoscalar
quadrupole vibration of the nucleus 208Pb and foundthe usual low energy and giant resonance peaks at low
temperatures whereas all the strength is concentrated
in a low energy mode above a transition temperature ofaround 1.5 MeV. 2). In the present report we shall study
the collective isoscalar monopole mode in addition to
the quadrupole mode. The collective coordinate Q is
assumed to be the scaling factor and relates to the density in the form of Q3 = n(Q)lno, where no is equilibrium density. The resulting stiffness C(O) = d2f I dQ2
in Eq. 2 is well approximated by 3)*

Physik-Department, Technischen Universitat Miinchen** Institute of Physics, University of Aarhus
12

C(O) = 216.7A(l - 0.006T2)MeV.

(3)

The collective response functin in Eq. 1 has been evaluated for 208Pb. Its dissipative part is shown in Fig.
1 as a function of frequency for the temperatures of
T = 0.5, 2.0, and 3.0 MeV. The pronounced resonance is well reproduced. Contrary to the quadrupolecase, the resonance does not move to low frequency
with increasing T. Only the width becomes broader,since the width of the intrinsic single particle states becomes broader as in the case of quadrupole vibration.
40 )<' 10'

Fig. 1. The imaginary part of the collective response
function for 208Pb as a function frequency for T = 0.5,
2.0, and 3.0 MeV for the monopole vibration.

We can understand the reason why the quadrupole
and monopole resonances behave so differently withincreasing temperature. At zero temperature, our formalism can well reproduce the resonance energy forboth the quadrupole and monopole vibrations. Even
at a finite temperature the resonance energy is determined by the RPA dispersion equation 1 )X(Oo) - X(O) = C(O).

(4)

As the stiffness C(O) comes close to zero, the resonance energy no comes close to zero-frequency. For
the quadrupole vibration, the stiffness C(O) is well estimated by the shell correction energy which disappears
around T = 1.5 MeV, while the stiffness C(O) for themonopole vibration weakly depends on the temperature (see Eq. 3).
References
1) S. Yamaji, H. Hofmann, and R. Samhammer: Nucl.
Phys. , A475 , 487 (1988).
2) H. Hofmann, S. Yamaji, and A. S. Jensen: Phys. Lett.,
B286, 1 (1992) .
3) C. Guet, E. Strumger, and M. Brack: ibid., B205, 427(1988).

RIKEN Accel. Prog. Rep. 27 (1993)

Classical Quantization of ,-Soft Rotor
N. Onishi
Classical Quantization, TDHF, Periodic orbits, ,),-soft rotor, Geodesic[ in the four dimensional sphere.
For highly non-linear quantum systems like nuclei,
the time dependent Hartree-Fock (TDHF) theory is
considered to be suitable.1) This theory has a classical feature and therefore it is necessary to requantize
the wave packets to obtain stationary states. To apply such a classical quantization as Bohr-Sommerfeld'squantization, one has to find periodic orbits in the solutions. Since no general methods finding the periodic
solutions are available for the full-TD HF, one should
try to find them case by case.
Another method to obtain stationary states is totruncate a subspace from the full- TDHF space. We
applied this method to obt ain the wobbling motion. 2 )We learnt many aspects in the course of this study.
In order to extend this method, especially to study
a topological structure of the phase space, we tried asemi-classical treatment of the macroscopic model suchas Bohr's hydro dynamical model.
As a simplest model in the framework of hydrodynamics, we take the ,-soft rotor which was studied intensively by Wilets-Jean,3) intending to make a clear
topological stucture of the classical orbits. This specific model has a nice feature of symmetry, 0(5). The
seniority is a good quantum number, which is the ang~lar momentum of the five-dimensional space. 4) We

1solved a differential equation of the classical motion
and found all classical orbits closed independently fromthe initial conditions. We calculated the action integral
and quantized the states to obtain the energy spectra,
which correspond completely to those obtained fromthe purely quantum mechanical procedure. 5 ) From theanalysis, the topological structure is found interesting.
It is shown that the classical motion of a ,),-soft rotor
is reduced to the free motion in S4 space. Therefore
the trajectory is a geodesic in S4 space forming closed
orbits. Even if the orbits projected onto two dimensional space of ')' and the conjugate mometum P"I lookrather complicated, it is clearly seen that all orbits areclosed. It will be very interesting to see how the closed
orbits distribute, if the S4 space is deformed by theinteraction which breaks 0(5). Now the investigation
is proceeding.

References
1) H. Reinhaldt: Nucl. Phys., A346, 1 (1980).
2) N. Onishi: ibid., A456, 279 (1986).
3) L. Wilets and M. Jean: Phys. Rev., 102, 788 (1956).
4) G. Rakavy: N1J,cl. Phys., 4 , 289 (1957).
5) N. Onishi and Dong-il Chang: ibid., A557, 301c (1993).

13

RIKEN Accel. Prog. Rep. 27 (1993)

Tilted Axis Rotating States in 1820s Yrast
T. Horibata and N. Onishi[,),-deformation, Three-dimensional rotation, Wobbling motion.]
We found tilted axis rotating solutions in the yrast
states of 1820S by a self consistent three dimensional
cranking calculations. Our method is based on the TDHFB which is derived from the time dependent variational principle.1) Since the method is free from therestrictions of the linear approximation, we can manipulate solutions in a region far from where such approximate methods could reach. Present solutions suggest
a possible new interpretation for the backbending phenomena.
Chowdhury et al. 2) reported an observation of highK isomers which decay abnormally fast into theyrast state in 1820s. They claim that the large,),-deformation mixes the K -quantum number andprompts the penetration between the high-K isomeric
deformation aligned prolate state and the well known
rotation aligned state. On the other hand, the wobbling motion caused by the Coliolis interaction which
is predicted to appear as a part of high spin survivalsof ,),-vibrational band is also predicted in this nucleus.
Since the wobbling motion accompanies shape oscillations, the ,),-deformation freedom is also expected toplaya crucial role in the dynamics.
In this report we focus our discussion on the character of three dimensional potential surface of the nucleus. We employ the HFB space in order to take into
account the pairing correlation. We truncate a model
subspace from the full HFB space, in which wave functions are labeled by the three components of angularmomentum referred to an intrinsic frame. The intrinsic frame of coordinate system is determined such thatthe principal axis (PA) of the mass quadrupole moment becomes the axis of coordinate system. Thus we
obtain the variational equation with eight constraints.
Those are the components of the angular momentum,
the mass quadrupole moments and the particle numbers.

0\ if - t(Il.J. S.B.)- ~A,N,]<I>)
<1>[

14

+

=0

The model hamiltonian employed in the present calculations is the pairing plus Q-Q force. First we performed the calculation for one dimensional rotation
about the principal axis (PAR). The g-band crosses
the s-band at J = 1411,. After constructing the PARyrast we launched off from the PAR-states to explore a vast unknown three dimensional potential field
where any self consistent calculation has never been
performed for the HFB-space. In Fig. 1 we show apotential surface obtained by the present calculation
at J = 1511,. We found a local energy minimum at
a distant point from the PAR-state. The energy ofthe point is about 0.3 MeV lower compared to thatof the J = 1511, PAR-state. The result suggests anexistence of tilted axis rotating states (TAR) and thestates possibly join the members of new yrast states.
Potential Surface Around Tilted Axis at J= 15
Energy (MeV)
0.4

0.2
0.0
-0.2

o

o
Fig. 1. The energy surface of J
151i sphere. The
direction of angular momentum vector is represented
by east-longitude and latitude.

References
1) A. K. Kerman and N. Onishi: Nucl. Phys ., A361 , 176(1981); N. Onishi: ibid. , A456 , 279 (1986).
2) P. Chowdhury et al.: ibid. , A485 , 136 (1988).

RIKEN Accel. Prog. Rep. 27 (1993)

Asymmetric Nuclear Matter and Finite Nuclei
N. F'ukunishi[Asymmetric nuclear matter.]
Discovery of the halo nucleus 11 Li 1 } has made thestudy of neutron-rich nuclei one of the mainstreams ofthe nuclear physics. The binding mechanism of halo
nuclei, two-neutron correlation in the halo part and its
effects on the nuclear reactions attract much interest.
Although the neutron halo is a very interesting phenomenon, it may be one of the interesting aspects ofneutron-rich nuclei. The present status of the study ofneutron-rich nuclei is restricted to light nuclei mainly
because of experimental difficulties. We expect andbelieve that these experimental difficulties will be overcome in the near future.
Our purpose of this work is to investigate how thebulk properties of nuclei will change with many excess neutrons. Numerical calculations have not been
finished. Thus, we will discuss briefly what we are interested in. First of all, we must investigate how far
away from the f3 stability line the nucleus exists. The
mass formula of Myers and Swiatecki2 } predicts that
N /Z = 2.25 gives the neutron drip line for nuclei with
A = 40-80. Here, N,Z, and A mean the neutron, theproton and the mass number, respectively. Note that
this predicted value does not include the pairing andshell effects. Thus, a highly degenerate orbit near the
drip line would allow the existence of more exotic nuclei, if the nuclear deformation does not take place inthese nuclei. To investigate this possibility is one of
our interests.
Weiss and Cameron discussed3 } that the saturation
density changes in the neutron-rich nuclei. According
to them, the saturation density is expected to be 15%
smaller at N /Z = 2.3 than in the stable nuclei. It isa natural consequence of the Fermi-momentum dependence of the symmetry energy. It is very interestingthat saturation properties may change with many excess neutrons.
The effective mass is one of the important quantities.
In stable nuclei, the effective mass at the Fermi surface
is nearly 1. On the other hand, it is predicted to beabout 2/3 for occupied states away from the Fermi
surface. Skyrme interactions, which are used widely,predict that the effective mass of the neutron becomes
greater as the neutron number increases. On the other
hand, that of the proton decreases with the neutron
excess. The effective mass determines the density ofstates. Thus, it is one of the key ingredients when
we discuss the possibility of the deformation in theneutron-rich nuclei.
We are also interested in the effective interaction in

neutron-rich nuclei. Our approach which will be explained just below can answer how the pairing interaction, the quadrupole-quadrupole interaction and thespin-orbit interaction change with the neutron excess.
With our best knowledge, fully microscopic investigation has been missing.
.
Microscopic calculations, which are based on therealistic nucleon-nucleon interaction and the nonrelativistic Brueckner-Bethe-Goldstone4 } equation, areplanned to investigate these quantities. The relativistic Brueckner-Hartree calculation5 } has been carriedout for finite nuclei with many excess neutrons. On
the other hand, neutron-rich nuclei are not enough investigated in terms of the non-relativistic many-bodytheory with the realistic nuclear force. Our approach
is made of two steps. The first is the G-matrix calculation in the asymmetric nuclear matter. In thiscalculation, we treat the Pauli operator exactly,6} andit is the most important difference between the calculation which we plan and many preceding calculations for the asymmetric nuclear matter. 7} Thus, we
can discuss clearly effects of excess neutrons. The second step is application of the results in the asymmetricnuclear matter to finite nuclei using the Local Density
Approximation (LDA) and the Density Matrix Expansion (DME).8,9) This approach is used for stable nuclei
by Negele et al. It is also effective for neutron-rich nuclei with the similar accuracy, because the short-range
nature of the nuclear force justifies this approximate
treatment for finite nuclei.

References
1) I. Tanihata et al.: Phys. Lett., 160B, 251 (1985); I.
Tanihata et al.: Phys. Rev. Lett., 55, 2676 (1985).
2) W. D. Myers and W. J. Swiatecki: Nucl. Phys., 81, 1(1966).
3) R. A. Weiss and A. G. W. Cameron: Can. J. Phys., 47,
2171; 2211 (1969) .
4) K. A. Brueckner, C. A. Levinson, and H. M. Mahmoud:Phys. Rev., 95, 217 (1954); J. Goldstone: Proc. Roy.
Soc., A239, 267 (1957).
5) R. Brockmann and H. Toki: Phys. Rev. Lett., 68, 3408
(1992).
6) T. Cheon and E. F. Redish: Phys. Rev., C39, 331 (1989).
7) For example, I. Bombaci and U. Lombardo: ibid., C44,
1892 (1991).
8) J. W. Negele: ibid., C1, 1260 (1970).
9) J. W. Negele and D. Vautherin: ibid., C5, 1472 (1972).

15

RIKEN Accel. Prog. Rep. 27 (1993)

Neutron-Skin and Proton-Skin Formations in
Exotic Nuclei Far from Stability
N. Fukunishi, T. Otsuka, and I. Tanihata[Neutron skin, Proton skin, Exotic nuclei.]
The neutron skin of the nucleus has been one of thecentral issues of nuclear structure. I,2) The definitionand presence of the neutron skin, however, have remained open problems for decades. It is only recent
that thick neutron skins have been seen experimentally, although only quite light nuclei such as 6He and
8He were investigated. 3 ) We discuss the formation of
the neutron skin and its physical importance briefly.
We employ the open-shell Hartree-Fock + BCS approach for several isotope chains, assuming the spherical equilibrium. 4 ) This treatment of the open-shell nucleus does not give the correct ground state properties,
but gives average properties of low-lying states. However, it should be rather irrelevant to our major results,
because we restrict ourselves to bulk properties such as
densities which are rather common among those states.
To discuss the neutron skin, let us introduce a quantity, the "skin thickness". In the neutron skin, theneutron density Pn (r) must be much greater than the
proton density pp(r). In addition to it, the neutron
density itself should not be too dilute. It is needed
to distinguish the neutron skin from the neutron halo.
These two conditions give the inner boundary Rl andthe outer boundary R2 as follows;
Pn(r) ~ 4pp(r) for r ~ Rl1

Pn(r) ~ lOOPn(O) for r ~ R 2 •The skin thickness is defined as R2 - R I . When R2
is smaller than R I, we set the skin thickness equal to
zero.
Figure 1 shows the skin thickness as a function of theneutron number (N). We find the continuous growthof the skin thickness as N increases. It reaches morethan 11m for nuclei with N /Z > 2. It is surprising thatthe neutron number in the skin reaches about twelve
for 18ICs (N = 126).
Figure 1 suggests a strong correlation between theneutron skin and the stability of the nucleus. Whatis the key ingredient of the formation of the neutron
skin? The answer is the difference of the Fermi energies between the proton (e~) and the neutron (e};:)In stable nuclei, elj, is almost the same as e~. The
strong proton-neutron interaction violates this "bal:..
ance" in the neutron-rich nuclei. As the neutron number increases, eIJ. goes up, which reaches nearly zero in
the drip-line nucleus. The small Fermi energy of theneutron leads to slow fall off of the neutron density.
On the other hand, excess neutrons give much attraction to protons, resulting in the deeper mean-potential
16

-3

g3

!

lIP)
lIP)

cu

(b) Cs isotopes
2

lIP)
lIP)

.e 2"~a)_41)----~g_._._.- a

.e

~ 1

()

~

1 f-

] Of-'

] 0

CIl

CIl

10

15 20
N

25 30

fl

I

I

J

60

80

100

120

N

Fig. 1. (a) Skin thickness in fm for Na (dot-dashed line),
Mg (dashed line) and Al (solid line) isotopes as a function of the neutron number, N. (b) Skin thickness in
fm for Cs isotopes.

for protons. It causes stronger damping of the protondensity, in addition to the existence of the Coulomb
barrier. Thus, the shape proportionality between the
proton and neutron densities is broken in the outerregion of nuclei with N » Z, and the neutron skinemerges. This mechanism of the neutron skin formation is a general one , and indicates that the neutron
skin should occur rather independently of minor detailsof calculations. One of the other Skyrme interactions(SGII)5) gives basically the same results as shown in
Fig. l.
The neutron skin opens up new fields of interest. It
is rather likely that the neutron skin affects the nuclear
deformation and the giant resonance of the nucleus. A
new type of deformation, in which the shape proportionality of the proton density and the neutron density
is broken, or a new mode which is primarily comprisedof the neutron particle-hole excitation is expected dueto the fact that the neutron surface is away from theproton surface. The neutron skin is also expected tohave a prominent effect on nuclear reactions. Whenan unstable nucleus with the neutron skin approaches
a stable nucleus, neutrons in the skin can touch theother nucleus before protons can do so. The differenceof elj, may behave as a driving force of the fast neutron
flow from the neutron-rich to the stable nucleus.
References
1) A. Krasznahorkay et al.: Phys. Rev. Lett., 66 , 1287
(1991).
2) W. D. Myers, W. J. Swiatecki, and C. S. Wang: Nucl.
Phys., A436, 185 (1985).
3) I. Tanihata, D. Hirata, T. Kobayashi, S. Shimoura, K.
Sugimoto, and H. Toki: Phys. Lett., 289B, 261 (1992).
4) N. Fukunishi, T. Otsuka, and I. Tanihata: Phys. Rev.,
C48, 1648 (1993).
5) N. Van Giai and H. Sagawa: Phys. Lett., l06B, 379(1981).

RIKEN Accel. Prog. Rep. 27 (1993)

How Many Nuclides Do Exist?
H. Sato and M. Uno[Nuclear masses, a-, proton-, neutron-, {3--, and {3+ -decays.]"How many nuclides can exist as a compact systemof proton number Z and neutron number N" is oneof the intriguing and fundamental questions in nuclear
physics. In this work, firstly we study the relationship between the history of the number of nuclides
found and the half lives of those nuclides observed. 1 )Next, we study the systematics of separation energiesof the {3--, {3+ -, proton-, neutron-, and a-emission decays of nuclides with both the mass observed experimentally and the realistic nuclear mass formula given
by Tachibana, Uno, Yamada, and Yamada2 ) (TUYY).
Figure 1 shows the a separation energies of nuclides in
the Z-N plane obtained with the TUYY mass formula.
The effects of the closed shell are nicely observed. Thenwe perform the calculation of {3- -, {3+ -decay half lives
with the nuclear gross theory and of proton-, neutron-,and a-emission decay half lives of nuclides with the Rmatrix theory employing the separation energies obtained with the nuclear mass formula given by TUYY.
And we study the systematics of those half lives in
the Z-N plane. Furthermore, we study the half life dependence of the number of nuclides, and discuss thenumber of unstable nuclei possibly found experimentally.

Fig. 1. The systematics of a Q values calculated with the
TUYY mass formula. 2 )References
1) H. Sato and M. Uno: Butsuri, 39, 892 (1984).
2) T. Tachibana, M. Uno, M. Yamada, and S. Yanada:
Atomic Data and Nuclear Data Tables, 39, 251 (1988).

17

RIKEN Accel. Prog. Rep. 27 (1993)

Systematics of Alpha Q-values: Potential Dependenceof the Alpha Decay Life Time
H. Sato[0:: decay.]

We study the 0:: decay half life of an even-even nucleus in terms of the 0:: S-factor defined by the ratio of
the experimental 0:: decay life t exp to the single 0:: decay life t o' :1) SO' = to'/t exp = r O'/rexp . Here rexp is theexperimental 0:: decay width, and the single 0:: widthr 0' is defined by: r 0' = 2p"'(2 with the penetrability P
and the reduced width "'(2 given by
2

1i

2

"I - 21-'a c

,
I

.II

D...

><
w
~

"...J

~

U

T..

U.

J

A

l.J1

U /¥

~

,,

J

'/'f

"

·N~ T-.J '1M

en

IUN L(a c ) 12

1"<!UNL(r)!2 dr'

~
II

"\;

.I\"\.

.1

II

r rl.

\

where N is the node quantum number, and J..L is the
reduced mass. The channel radius ac is chosen to bereasonably large. The wave function uNL(r) is a solution of the one body equation of the o::-A relative
motion given by

~

~

~

'Ill ,.

,

JI ..
raj
:1
\j

~

.
V'"

\

•

iIa.DOliIII.DO

11&0.00

IIID.IID

IIIII.DD

iIIID.DO

Z~D.DO,"D.DD

DD

MRS

Fig. 1. S factors derived with M3Y folding potential.

Here the 0:: Q value QO'A is taken from the compilation of Wapstra and Audi. 2) We employ the double folding potentials for U and Uc calculated by the
M3Y and Coulomb interactions with the nuclear density distributions generated by the Density Dependent Hartree Fock type variational calculation including shell corrections 3 ) with the Skyrme III interaction.
The parameter 9 is adjusted so as to reproduce QO'A
at each node quantum number N under the condition
that the UN L has a phase shift 7r /2 in the asymptotic
region.
Choosing an appropriate node quantum number N ,we calculate the S-factors and summarize those in
Fig. 1. To make a quantitative discussion, we study

18

decay half lives of 6+ and 8+ states of the ground bandof 20Ne and those of the ground and 18+ states of 212po
with theoretical S-factors (0.24 for 20Ne and 0.061 for
212p04)), and find nice agreements with experimental
data except 18+ of 212pO.
The author would like to thank Professor M.
Ishihara for his encouragement.

References
1) A. Arima and S. Yoshida: Phys. Lett. , B40, 15 (1974);
Nucl. Phys., A219 , 475 (1974) .
2) A. H. Wapstra and R. Hoekstra: Atomic Data and Nuclear Data Tables, 39, 281 (1988).
3) K. Yazaki: Nucl. Phys. , A277, 189 (1977) .
4) I. Tonozuka and A. Arima: ibid. , A323 , 45 (1979) .

RIKEN Accel. Prog. Rep. 27 (1993)

Relativistic Density Dependent Hartree Approachfor 16 0 , 40Ca, and 208Pb
R. Brockmann and H. Toki
[Relativistic density dependent Hartree approach, rearrangement term, isovector interaction.]
The relativity has been demonstrated to be a key ingredient to describe the nuclear saturation property using the Relativistic-Brueckner-Hartree-Fock (RBHF)
theory.!) We have then developed a method to describe finite nuclei using the RBHF results of nuclear
matter. 2) This new method, named as relativistic density dependent Hartree (RDDH) approach, is able toreproduce the binding energies and radii of 16 0 and
40Ca. As a next step, we study the effects of the rearrangement term and the isovector interaction for heavy
nuclei.
The effect of the rearrangement term due to the density dependence of the effective interactions has beenstudied by many authors for the non-relativistic case.
We can include this effect also for the relativistic casein the similar way. We will show the details of calculations in a future publication. 3) The calculated results are summarized in Table 1. As discussed in theprevious publication for 16 0 and 40Ca, the RDDH results compare extremely well with experiment. 2) The
binding energy per particle and the charge radius areslightly underestimated. The similar behavior is foundalso for the case of 208Pb, where only the isoscalarinteraction (sigma and omega mesons) is considered.
Table 1. Binding energy per particle and charge radius forvarious nuclei. RDDH and RDHR are the relativistic
density dependent Hartree theory without and with therearrangement term, respectively, which are comparedwith the experiment denoted by Exp.

The results with the rearrangement term are depictedin the column headed by RDHR. The binding energy
is not much influenced, while the radius is increased
by about 0.1 fm. Hence, the radius is improved byintroducing the rearrangement term.
We discuss now the inclusion of the isovector interaction (rho and delta mesons) for NjZ asymmetric nuclei.
We extract the density dependent coupling constantsfor the rho and omega mesons from the RBHF resultson both the nuclear matter and the neutron matter.
Again the details of this extraction will be shown ina future publication. 3 ) The numerical results for 208Pb
are; Bj A = 6.985 MeV and Rc = 5.214 fm. The isovector interaction acts repulsively for the binding energy
and makes the agreement with the data worse. As
the net effect, the binding energy is underestimatedby about 1MeV for 208Pb. Since the symmetry energyof the RBHF theory comes out reasonable, we believe
this under binding originates from the isoscalar part.
It would be very important to point out that the finite
nuclei would be reproduced once the nuclear matter
properties are reproduced.
In conclusion, we have now a many body theory
to describe the saturation property of nuclear matter.
With the use of this result, we find a straightforward
approach as the RDDH can describe also finite nuclei.
The relativity produces as very important effects thethree body interaction and the spin-orbit interactionin the language of the non-relativistic framework.
References

Nucl.
16
0
40Ca
208Pb

E/A [MeV]Rc [fm]
RDDH RDHR Exp RDDH RDHR
7.402
7.420 7.98 2.622
2.736
7.901
7.943 8.55 3.328
3.429
7.440
7.440 7.87 5.222
5.302

Exp
2.75
3.48
5.50

1) R. Brockmann and R. Machleidt: Phys. Rev., C42,
1965 (1990).
2) R. Brockmann and H. Toki: Phys. Rev. Lett., 68, 3408
(1992).
3) R. Brockmann and H. Toki: to be published.

19

RIKEN Accel. Prog. Rep. 27 (1993)

Systematic Study of Sr Isotopes in the
Relativistic Mean Field Theory
D. Hirata, H. Toki, I. Tanihata, and P. Ring*[N uclear Structure, binding energy, isotope shifts, deformation, relativistic mean field theory.]
Recently, using the nuclear radioactive beams, it becomes possible to study experimentally the unstable
nuclei, in particular, those with large neutron excess.
This technique enables us to study the structures of
unstable nuclei and then find many interesting phenomena such as neutron halos and neutron skins.1,2)
It is very interesting for theoreticians to study the
structures of unstable nuclei with a reliable model. We
choose the relativistic mean field theory (RMF) for
this purpose. This is due to the recent success of therelativistic Brueckner-Hartree-Fock calculations on nuclear matter and we also found that the RMF theory
using the NL1 parameter set describes spherical unstable nuclei well. 3)
The mean square nuclear charge radii <~r2> in along series of isotopes appear to be an important toolin the analysis of the structure of ground states of unstable nuclei because they give informations about new
regions of deformation. The Sr (Z = 38) isotopes are
particularly interesting, since an experiment performedby the ISOLDE group at CERN 4 ) provided systematically the <~r2> from A = 78 to 100. The data showa large jump in the <~r2 > at A around 98 indicatingthat the nuclei in that region are strongly deformed.
Hence, we calculated <~r2> using the RMF theory
with deformation using the NL1 parameter set andcompare the results with the experimental data. 5 )We have performed constraint calculations to thequadrupole moment in order to obtain all local minima
in the energy curve.
We show in Fig. 1 the binding energy per particle forall possible solutions, as a function of the mass number. The behavior of the E / A is reproduced quite wellin the RMF theory, although we found a missing binding energy on the neutron rich side which we attributeto the strong p meson coupling strength in the NL1parameter set.
Figure 2 shows the isotope shifts of Sr isotopes fromA = 78 to 100 relative to A = 88 for all possible
minima obtained and compared with the data. The
small increase of the isotope shifts toward the protonrich side observed experimentally is not described wellwhen the small deformation is chosen and the large deformation gives larger isotope shifts than the experimental values. The strong increase for the neutron richside is well reproduced if the large oblate deformationis chosen, and the jump at A = 98 is also reproduced
if the large prolate solution is selected.

*
20

Physik Department cler Technischen Universitat Miinchen-8. OI-",--,~~~""""""---L-~"""""'----'--'
76 80 B4
88 92 96 100 A

Fig. 1. The binding energy per particle E / A for Sr isotopes
as a function of the mass number (A). The experimental data are shown by solid circles and the calculated
ones by the open eliptics, indicating the shapes of thepossible solutions.

~
~

2.0

0 00
0

11.6

o •

:5, 1.2
.;::

1\

i

~1.J0.8

0
0

8- 0
°0 0

••

o

.~

.......
0.0

i

0 0

0

v

0.4

0

+

0

.·fjfJ<PoCb~o-0.4 76

80

84

88

92

96

l00A

Fig. 2. The isotope shifts normalized to A = 88 for Sr
isotopes as a function of A. The data are shown by solid
circles and the calculated values by the open eliptics.

The discrepancies seen in Figs. 1 and 2 may be solved
with the addition of the angular momentum projection
and the triaxial deformation, but the present study isalready able to explain the gross structure of the Sr
isotopes.
References
1) I. Tanihata et al.: Phys. Rev. Lett., 55, 2676 (1985).
2) I. Tanihata et al.: Phys. Lett., B289, 261 (1992).
3) D. Hirata et al.: Phys. Rev., C44, 1467 (1991).
4) C. Thibault et al.: ibid., C12, 644 (1975).
5) D. Hirata et al.: Phys. Lett., B314, 168 (1993).

RIKEN Accel. Prog. Rep. 21 (1993)

Relativistic Mean Field Theory for the
Isotope Shifts of Ba, Cs, and Xe
D. Hirata, H. Toki, and 1. Tanihata[Nuclear Structure, isotope shift, deformation, relativistic mean field theory.]
There is an explosive interest in the study of unstable nuclei after the technical advance of unstable

1.6

ogS
8°

1.2

1
"I

SS

0.8
0.4

co

:i

1\

0
0.0

"I~

'0:::1

v

-0.4

,"

o

o.··I~~O
~

o~~

-0.8

~

trB,

Xe

1.0

st

0.8

8

0.6
N

-E

~

z~

1\
"I....u'0:::1

v

~

0.4

oi

0.2
0.0

0° a

~c:

of/J~

-0.2
-0.4
-0.6
60
f-

lj

1.8 I0

1.4 _

~

1.0 _

i

08

co

'0:::1

v

~

0.2 _

1\

N~

-0.2

B

!o

0.6 _

"I

:i

8

~

~ ..... ~~o-o! aSB~O-0.6 _

0

-1.0
60

I

I

I

I

I

I

I

66

72

78

84

90

96

102 N

Ba

00

Fig. 1. The isotope shifts normalized to N = 82 for
Xe and Ba isotopes and, to N = 78 for Cs isotopes,
respectively, as a function of neutron number. The experimental data are indicated by solid circles and thecalculated values by open eliptics denoting the shapesof the possible solutions.

nuclear beams.!) We are learning, in nuclei near the
drip lines, many nuclear phenomena that have notbeen observed in stable nuclei. 2) One of the important systematic studies of unstable nuclei is pursued
by the ISOLDE group at CERN using the laser spectroscopy. The measurement of the isotope shifts of
54Xe, 55CS, and 56Ba shows a strong magic number
effect at N = 82 in addition to some deviation of theisotope shifts from the systematics around N = 64
in Cs. 3 ) The non-relativistic Hartree-Fock theory provides the magic number effect at N = 82, but the effectis not so large as the data indicate.
On the other hand, the RMF theory has been
demonstrated to work very well for unstable nuclei. 4)
It is therefore very interesting to apply the RMF theory to these nuclei including the deformation degreeof freedom. We use a newly obtained parameter set
constructed by Sugahara and Toki, which includes the
non-linear w term. 5) We have performed constrained
calculations to the quadrupole deformation and hence
find several minima for each isotope.
We show in Fig. 1 the calculated results for isotope
shifts of Xe, Cs, and Ba as a function of the neutron
number. Nuclei Xe and Ba with an even proton number, show similar behavior for the isotope shifts. Thechange of the isotope shifts at N = 82 in calculation
is not as drastic as the data show. The isotope shifts
below N = 82 are underestimated significantly. However, the appearance of an energy minimum solution
at large prolate deformation for several nuclei aroundN = 66 provides a good account of the data. The
overall agreement is seen for the case of the Cs isotopes which have an odd proton number. The jumpof the isotope shifts seen in the experiment aroundN = 64 may suggest the large prolate deformation,
which is one of the energy minima for these nuclei. It
would be important to accumulate the information forsystematic understanding of unstable nuclei.
References
1) 1. Tanihata: Treatise on Heavy Ions Physics, 8, 443(1989), and references therein.
2) 1. Tanihata et al.: Phys. Rev. Lett., 55, 2676 (1985).
3) P. Aufmuth et al.: At. Data Nucl. Data Tables, 31, 455(1987).
4) D. Hirata et al.: Phys. Rev., C44, 1467 (1991).
5) Y. Sugahara and H. Toki: TMU preprint (1993) .

21

RIKEN Accel. Prog. Rep. 27 (1993)

Instability of the Degenerate Electron Gas
K. Tanaka[Instability, infrared divergence, electron gas.]
The degenerate electron gas is a classic model ofthe many-body problem. It is a system of interacting
electrons placed in a positively charged uniform background to ensure the neutrality of the system, and is
expected to serve as a model of electrons in metals orin astronomical objects like white dwarfs and neutronstars.
In the nonrelativistic (NR) case, the energy density!)
and the quasiparticle spectrum in the vicinity of the
Fermi surface 2 ) were obtained as a high-density expansion, where the principal approximation is the RPA tosum up the dominant infrared-divergent terms, giving
finally the finite results. Also, in the relativistic case,the resummation of the RPA series was required to obtain the finite result for the energy density. 3) In thispaper, we investigate the quasiparticle spectrum in therelativistic RPA, corresponding to the energy density
computation of Ref. 3. We employ a recently developed
technique4 ) to extract the dominant infrared singularities in the Fermi velocity, and investigate the behaviorof the quasiparticle spectrum near the Fermi surface.
We find that the Fermi velocity suffers from the infrared divergence even in the RPA , in contrast to the
NR case: If we include only the exchange self-energy
correction, we obtain the result consistent with the NR
case, i.e. , the infinite positive slope of the quasiparticle spectrum at the Fermi surface due to the infrared
divergence. This indicates the inadequacy of the approximation and suggests the resummation of the RPA
series. By including further the RPA self-energy contribution, we find:1
OVF = -2(e2;-(PF ) ) 2

2

Vo

{p~
In A2 + 0(1)

},

(1)

as the correction to the Fermi velocity of the free electron gas Vo = PF / P~ + M2 (PF the Fermi momentum and M the electron mass). e(PF) is the running
coupling constant at the momentum scale PF , and A

J

22

is the fictitious photon mass to cut-off the infrared
divergence. The result indicates the infinite negative
slope of the spectrum at the Fermi surface and therefore instability of the normal state for any density. Furthermore, this does not reduce to the corresponding(finite) result 2 ) in the NR limit.
The essential ingredient leading to the breakdownof the RPA in the relativistic case is the interactions
via the exchange of the transverse photons. They havebeen neglected in the NR case as relativistically higher
order effects of 0(v5). However , as shown in Eq. 1,
they give the infrared divergent cor.tribution even after
summing up the complete RPA series, due to the factthat the screening mass for the transverse modes iszero. This means that the NR treatment neglecting
those degrees of freedom is illegitimate.
There has been no empirical indication of such instability of the Fermi surface as discussed above. In orderto get the result consistent with the observation, one
would at least have to include the higher order terms
beyond the RPA. However, since it can be proved thatthe transverse screening mass is zero for the arbitraryorder of perturbation theory, one might have to include
nonperturbative effects beyond perturbation theory, or
the degrees of freedom beyond the original model, e.g. ,phonons in the case of metals. We also note that theextension of our arguments would indicate the instability of the normal state for other gauge theories, e.g.,
for quark matter.
References
1) M. Gell-Mann and K. A. Brueckner: Phys. Rev., 106 ,
364 (1957).
2) M. Gell-Mann: ibid. , p. 369.
3) I. A. Akhiezer and S. V. Peletminskii: Sov. Phys. JETP,
11, 1316 (1960); B. Jancovici: Nuovo Cimento, 25, 428(1962).
4) K. Tanaka: RIKEN preprint, RIKEN-AF-NP-160(1993).

RIKEN Accel. Prog. Rep. 27 (1993)

Quasiparticle Properties and the Dynamics ofHigh-Density Nuclear Matter
K. Tanaka[Quasiparticle spectrum, high-density nuclear matter.]
One universal character shared by most normal
Fermi liquids is the enhancement of the effective massaround the Fermi surface.1) The relevant mechanismis the dynamics beyond the mean-field theory, i.e. , thecoupling of the single-particle motion to particle-hole(ph) excitations in the case of nuclear matter.
The investigation of the high-density behavior of
the effective mass including those many-body correlations would be relevant to understand , e.g., stellar
structure or evolution and high-energy heavy ion reactions. This requires a relativistic framework of Fermi
liquids. In this paper 2) we compute the quasiparticle spectra employing the 1/N expansion method for
the CTW model. 3) (N is the extended number of nucleon species.) Based on the Landau theory of Fermi
liquids,4) the quasiparticle energy in nuclear matter,corresponding to the energy density up to the next-toleading order, is obtained: This contains, in addition
to the leading Hartree term of 0(1) , the exchange and
RPA self-energy terms of 0 (1/ N) .
We find that , for high densities, the spectra showthe "anomaly" around the Fermi surface, i.e., they
are flat or decreasing due to the inclusion of the RPA
self-energies. This anomaly corresponds to the effective mass enhancement discussed above, and the effectgrows with increasing density. Figure 1 shows the realpart of the quasiparticle energy for the "flat" case.
The growth of the anomaly can be understood byexamining the high-density asymptotic behavior of the
Fermi velocity VF. We obtain for PF ~ 00 (PF theFermi momentum):2)
VF~ 1 - ~ (gw (PF ) ) 2 {In P~ + 0 (I)} ,
2

27r

m~

(1)

where mw is the w-meson mass and gw(PF) is the running coupling constant at the scale PF for the nucleon-w
vertex. The first term ("1") is due to the Hartree term
while the second term is the contribution due to the0(1/ N) self-energies. The result is governed by the
infrared singularity for mw/PF ~ 0, and can be traced
back to the fact that the the transverse screening massof the vector bosons is zero, in contrast to a nonzero
Debye screening mass for the longitudinal mode.
Thus, the anomaly in the spectra is due to the strong

2900

'>

2800

., .,

Q)

21
::II

2700

~
w

2800

., .,

Q)

~

., .,

.,

-----~c:J--- . . --. .
......

2600......

3

3.6

•

•. 6

6

6.6

p [fm- l ]Fig. 1. The real part of the quasiparticle energy as a function of momentum for the case of PF = 4.07 fm - l. The
solid line shows the full result including the O(l/N)
self-energy contributions, while the dot-dashed line is
the Hartree contribution contained in the full result.
The insertion shows the 0(1/ N) self-energy contributions as functions of momentum. The dotted anddashed lines are the exchange and RPA self-energy contributions, respectively.

infrared behavior caused by the coupling of the ph excitation to the single-particle motion. Though a more
realistic treatment would be required to fix the relevance to phenomenology, the universal character ofthis phenomenon already poses various interesting aspects for high-density matter, like the possibility of the
new phase 5 ) above the critical Pp where VF = 0, thethermodynamic properties and transport phenomenain this phase, and the extension to gauge theories. 6 )References
1) C. Mahaux, P. F. Bortignon, R. A. Broglia, and C. H.
Dasso: Phys. Reports, 120, 1 (1985).
2) K. Tanaka: RIKEN pre print , RIKEN-AF-NP-160(1993) .
3) K. Tanaka, W. Bentz, and A. Arima: Nucl. Phys., A555,
151 (1993).
4) L. D. Landau: Sov. Phys. JETP, 3 , 920 (1956).
5) C. J. Horowitz and B. D. Serot: Phys. Lett., B109, 341(1982).
6) K. Tanaka: This report, p. 22.

23

RIKEN Accel. Prog. Rep. 27 (1993)

General Formula of the Coalescence Model
S. Hirenzaki, T. Suzuki, and 1. Tanihata[Coalescence model, Pi-neuts.]
The coalescence model has been widely used to calculate the formation cross sections of composite particles using the cross sections of constituent particles. In
the model, particles in a coalescence phase volume areassumed to produce the composite particle. We havedeveloped the general expression of the coalescence factor for the formation of arbitrary composite particles 1)
using the density matrix formalism. 2 ) This expression
is extremely useful and can be used to estimate theformation cross section of any kinds of composite particles such as hypernuclei, multi-hypernuclei, mesonicatoms, multi-mesonic atoms, pi-neuts, etc. As an example we have studied the formation cross section of
the pi-neut and showed that the analysis using the recent data strongly denies the existence of 7rn 2 .
In the coalescence model we can express the formation cross section of a composite particle "a" as follows;(1)

where A is the total number of constituent particles
that make "a" and the index i indicates an i-th particle. We denote the coalescence factor by Fe. To get theanalytic expression of the coalescence factor Fe under
the same assumptions as those in Ref. 2, we write themany body density matrix approximately as the product of the one body density matrix and assume theone body density matrix to have the following Gaussian form;

Pi (r, r') =1(7ra~)

3/2 exp [_~ (r + r') 2]ai

x Ciexp [- ;; (r - r')2] ,(3)

We can get the general expression of Fe using theseassumptions as follows;
F = S 29(A-l)/27r3(A-l)/2 [ITA (pex[t. 2<>; ~ 8;]

i=l

-3/2

2a~
t

1

+ 8t2

)

3/2]
(4)

where Sp is the spin factor. As an example we apply our result (Eq. 4) to calculate the formation crosssection of pi-neut (7rn 2 ). The pi-neut was searched indifferent systems and the upper limits of the formation
cross section were determined. 3 ,4) The upper limits ofthe formation cross section correspond to the upper
limits of Fe and those in turn restrict a and 8 parameters. Although the a and 8 were not measured directlyin these reactions, the restrictions are strong in thesecases because a is not expected to be much larger than
the size of colliding nuclei (:S 5 fm) and thus 8 has tobe larger than 28 fm.4) On the other hand 8 needs tobe small in size to make the pi-neut to be a boundsystem. 5 ) We conclude that the existence of pi-neut(7rn 2 ) is strongly denied by the recent data.
References2(2)where ai determines the spatial distribution of particle i in the particle emission source that is formed in a24

reaction. For internal wavefunctions of the composite
particle "a", we assume the Gaussian distribution foreach particle;

1) S. Hirenzaki, T . Suzuki, and I. Tanihata: Phys. Rev. ,C48 , 2403 (1993).
2) H. Sato and K. Yazaki: Phys. Lett. , 98B, 153 (1981).
3) T. Suzuki et al.: Phys. Rev. , C47, 2673 (1993).
4) F. W. N. de Boer et al.: ibid., D43, 3063 (1991).
5) H. Garcilazo: Phys. Rev. Lett., 50, 1567 (1983).

RIKEN Accel. Prog. Rep. 27 (1993)

Nuclear Recoil Effects in e+ -e- Pair Production
through 0+ -0+ Transition
H. Sato[e+ -e- production, 0+-0+ nuclear transition, recoil effect.]
The spontaneous and induced positron decay of thevacuum in a supercritical field is one of the production mechanisms of positrons (e + s) through low energy nuclear phenomena. Instead of the e+ from thespontaneous vacuum breakdown, however, anomalous
peaks (80 keY width at around 350 keY kinetic energy)
in the energy spectrum of e+ have been reported inheavy ion scattering experiments with GSI-UNILAC.
Moreover, electron (e - ) peaks, whose energy coincides
with those of e+s, were also observed. And a coincidence between e+ and e- in the peak energy region was
claimed. The presence of such a coincidence excludes
the spontaneous e+ emission mechanism as a source ofthe e+ peak. The observed coincidence intensity andthe shape of the spectra eliminate the possibility ofknown internal conversion processes. It is also pointed
out that the narrow peak in e+ spectra cannot be explained with the QED plasma consisting of e+s, e-s,
and photons. The production of a new neutral particle,
whose main decay mode is the e+e- pair production,is also implausible.
In this work, we study the nuclear recoil effect on
the e+ -e- pair production through 0+ -0+ transition interms of the nuclear center of mass motion trapped in
the crystal lattice. We study the e+ spectrum obtainedin connection with GSI experiments with special attention. The effects of the thermal motion and the vibrational motion in the lattice are studied as a nuclear

recoil. Figure 1 shows a typical e+ spectrum without Coulomb correction in the e+ -e- pair production
through 0+-0+ transition, whose nucleus is trappedin the crystal lattice at 300 K thermal motion. The
Coulomb correction reproduces the asymmetric shapein the e+ spectra. A division of peak is found to be atypical feature of the nuclear recoil effect. A study of
the relationship with GSI experiments is in progress.

2.5

>:.

'~"'
...,;..

2.0

1.5

'.-1

.D

'" 1.0

~

j:z:j

'0
........

z

'0

0.5

0.00

0.2

0.4

0.6

0.8

. Et (MeV)

Fig. 1. Nuclear recoil effects on e+ spectra in e+ -epair production through 0+-0+ transition at temperature 300 K without Coulomb corrections.

25

RIKEN Accel. Prog. Rep. 27 (1993)

Distribution of Perturbative Gluon in the MIT Bag Model
H. Kitagawa, Y. Nishino,* S. Tadokoro,** and T. Suzuki*[perturbative gluon, MIT bag model, structure function.]
The structure function is one of the important observables to explore the properties of the nucleon. It
can provide information of the nucleon from the data of
the high energy lepton-nucleon deep inelastic scattering (DIS). The structure function is composed of twoparts: the long-range part is assumed independent of
the high momentum scale involved and is estimatedusing an effective model such as the bag models,1) andthe behavior of the short-range part is obtained by the
perturbative QCD. By the QCD evolution to the relevant Q2 scale, it is possible to compare the calculated
structure function with the measured data. For thiscomparison, it is interesting to evaluate not only thenon-singlet part which contains only the quark distribution, but also the singlet part in which both quarkand gluon distributions are coupled. The gluon distribution has to be evaluated as the first step. We calculate it using the MIT bag model, and compare theresult with the parametrization of Duke and Owens. 2 )We define the unpolarized gluon distribution assuming the light-cone dominance astively from the quark wave function. For simplicity, we
do not consider the momentum projection. The gluon
distribution is calculated by the following equation,G(r) =

4"~X

Jdz

exp

C~z)

where B is the color magnetic field in the MIT bag
model, and a is the color index.
Result of the calculation is shown in Fig. 1. Compared with the parametrization of Duke and Owens,our result of gluon distribution, G(x), has strange oscillatory behavior and unphysical negative values. Thisoscillation is considered to reflect the feature peculiar
to the MIT bag model, which has a rigid surface. It
may be avoided by using other nucleon models, suchas the soliton bag model, or by including the effect ofthe momentum projection.
0.4

where F is the color electro-magnetic tensor, q is themomentum transfer, M is the nucleon mass, and~- = (~O _ ~3) lVi

q+ = (qO + q3) lVi.

It is possible to derive this expression by using theoperator product expansion technique. 3 ) The productof the electro-magnetic current JJ-L(~)' whose Fouriertransform is the hadronic tensor in the DIS, can be
expanded in the operator product expansion as

JJ-L(~)JV(O) =L C . OJ-LV ~ ... ~

0.3

H 0.2
t;'

0.1

0.0

Fig. 1. Unpolarized gluon distribution, G(x), calculatedwith the wave function in the MIT bag model is shown.
The abscissa is the Bjorken variable, x, which represents
the inelasticity of the scattering.

= (quark part) + (gluon part) + ...

where C and 0 are the coefficient function and the operator respectively. By considering the gluon operator
we can collect the gluon part, and obtain the above
relation.
We estimate the expectation value of the gluon operator 0 in the nucleon state, using gluon wave functionof the MIT bag model,4) which is obtained perturba-*

Research Center for Nuclear Physics, Osaka University** Institute for Nuclear Study, University of Tokyo
26

References
1) S. Tadokoro, H. Kitagawa, and T. Suzuki: Phys. Rev.,
D47, 3045 (1993).
2) D. W. Duke and J. F . Owens: ibid., D30, 49 (1984).
3) X. Ji: Phys. Lett., B289, 137 (1992).
4) T. DeGrand, R. L. Jaffe, K. Johnson, and J. Kiskis:
Phys. Rev., D12, 2060 (1975).

RIKEN Accel. Prog. Rep. 27 (1993)

Momentum Evolution of the Twist-three Part of
the Spin-dependent Structure Function
H. Kitagawa, S. Tadokoro,* and T. Suzuki**[structure function, momentum evolution, MIT bag model.]It has become possible to investigate the structuresof the nucleon by high energy lepton-nucleon deep inelastic scattering (DIS) experiments. By the recent
developments of technology, the measurement becomes
more precise, and we can discuss the observables which
depend on the nucleon spin as well as fine structuresof the nucleon. The observed asymmetry for scattering of polarized leptons off polarized nucleon target isexpressed in terms of the structure functions by thefollowing equation.
( dO" li - dO" II ) j (dO" li + dO" II )= D jWl [ (M vG l -Q 2G 2) + TJ& (MG l + vG 2)]

where D and TJ are kinematical factors, WI is the spin
independent structure function , and G l and G 2 are thespin dependent structure functions. These structure
functions almost scale in the Bjorken limit as

MWI - t Fl
vjM· G l - t 91
v 2jM2 . G 2 - t 92

Xn9l(X,Q2)dx = ~ an (J.1,2)F:;(Q2 , J-L2)n

X g2(X, Q2)dx =2(n: 1). [an (J-L2)F:;( Q2, J-L2) _ ~(J-L2)F;( Q2, J-L2)]
where 91 (x, Q2) and 92(X, Q2) are the spin dependent
structure functions, an (J-L2) and d n (J-L2) are the lowmomentum parts, and F:f(Q2,J-L 2) and F;:(Q2,J-L 2) are***

92(X) = 9f'w (x) + 92(X).
Since the twist-two part, 9fw (x), is obtained directlyfrom 91 (x), whose behavior has been well investigated,
we consider the remaining twist-three part, 92(X). For
simplicity, we calculate the second moment, whose momentum scale dependence has been given as,2)[(Q2)] 77/81
x 2g (x,Q 2)dx = -2.. d2(J-L2) ~o
2
3cx s (J-L2)

lol

We employ the MIT bag model,3) then the nonperturbative part, d2(J-L2), can be written analytically as,d2(J-L2) = - 2~2 < PSI~(O)B'Y1P(O) IPS >aside from a small QCD scaling violation.
We have investivated the nucleon structure functions, whose low energy structures are estimated by
the effective model of the nucleon, in particular, a bag
model assuming the parton picture to hold. 1) In order
to compare results of calculations with the observed
values, these structure functions at low Q2 have to be
evolved to high momentum scales.
For the momentum evolution, we employ therenormalization-group equation, by which the Q2 dependence of the perturbative parts is obtained. We
assume that the remaining nonperturbative parts canbe estimated by using the bag models. By the operator
product expansion, these two parts are related with themoments which are obtained by the experiment, i.e.

JJ

the twist-two and -three coefficient functions respectively, which are obtained by the perturbative QCD.
The term "twist" is related to the dependence on Q2
powers, and the "higher-twist" part can be obtained
from the precise data. We investigate 92 (x), observable of the transversely polarized spin state. This canbe divided into two parts

Institute for Nuclear Study, University of Tokyo
Research Center for Nuclear Physics, Osaka University

where M is the nucleon mass, 1P is the quark wave
function, and B is the color magnetic field which is
obtained perturbatively from the quark wave function.
The final result is
1
d2 = 2M2VJ

R2) G 2d3 r [ ( Rl + 3- 31 (Rl - R 2) F 2]
Rl(r) = [2M(r) + J-L(R)j R3 - J-L(r)jr 3] j47r
R2(r) = 3J-L(r)j47rr 3

M(r) =i/L(r) =

lor dr' /L'(r')

J-L'(r)R

dr' /L'(r')jr'3= 87rG(r)F(r)j3

where V is the bag volume, R is the bag radius, andG(r) and F(r) are the quark upper and lower components, respectively.
References
1) S. Tadokoro, H. Kitagawa, and T. Suzuki: Phys. Rev.,
D47, 3045 (1993).
2) X. Ji and C. Chou: ibid., D42, 3637 (1990).
3) T. DeGrand, R. L. Jaffe, K. Johnson, and J. Kiskis:
ibid., D12, 2060 (1975).

27

RIKEN Accel. Prog. Rep. 27 (1993)

Color Confinement, Quark-Pair Creation and Dynamical
Chiral-Symmetry Breaking in the Dual Ginzburg-Landau Theory
H. Suganuma, S. Sasaki, * and H. Toki
color confinement, quark pair creation, chiral symmetry, abelian monopole condensation,[ dual Meissner effect, Schwinger mechanism.
Recently, much attention has been paid on the dual
Ginzburg-Landau theoryI) for the study of the color
confinement of QCD. This theory is based on 'tHooft's
idea,2) that is, QCD is reduced to the abelian gauge
theory with abelian monopoles in the abelian gauge.
Like the superconductivity physics, condensation ofsuch a monopole field leads to the dual Meissner effect,
exclusion of the color-electric flux , which characterizes
the color confinement. 1)
We study various features of nonperturbative QeD
by using the dual Ginzburg-Landau Theory. To begin with, we derive the static potential between quark
and antiquark with opposite color charge by considering the quark-current correlation,I) in the pure-gaugecase. The result of the quark potential is shown in Fig.
1. One finds good coincidence between our result andthe Cornell potential, phenomenological one which reproduces the quarkonium data and lattice QCD datain the pure gauge.
2.0 r----r---r--r----r---r---,
1.0

;>

0.0

IV

Q.

~ -1.0~ -2.0-3.0 U---L_--'-_L---L_--'----'
0.000.250.500.75 1.00 1.25 1.50

R[frn]

Fig. 1. The static quark potential in the quenched approximation. The dashed curve denotes the Cornell potential.
Thus the confinement for heavy quarks is shown inthe dual Ginzburg-Landau theory. As for the string
tension, we find that its expression corresponds to thatof the energy per unit length of a vortex in the superconductivity physics.
Next, we study dynamical effects of light quarks. In
particular, the quark-antiquark pair creation plays animportant role in the screening effect of the confinement potential in the infrared region. 3 ) We estimate
the quark-pair creation rate in the hadronic flux tubes
by using the Schwinger formula,4) and take account of
the infrared screening effect for the confinement pot en-*

28

Department of Physics, Faculty of Science, Tokyo Metropolitan University

_

1

3.0

>
Q)

.Q.
~

~ 2.0
$
o

0..

C
Q)

e 1.0
=
8=
tc:

0.0

0.0

1.0

2.0

3.0

R[fm]

Fig. 2. The screening effect on the quark confinement
potential. The dashed curve corresponds to the linear
potential in the quenched approximation.
tial by introducing an infrared cutoff. Figure 2 shows
the modification of the confinement potential, linear
part of the quark potential, by the pair-creation effect. One finds the saturation of the confinement potential in a long-range region. Such a tendency has
been found in the recent lattice QeD data with the
dynamical quarks. 3 )Finally, we study the dynamical chiral-symmetry
breaking by solving the Schwinger-Dyson equation forthe light quark field. We find that the dynamicalchiral-symmetry breaking is largely enhanced by theabelian monopole condensation. The magnitude of
the chiral-symmetry breaking, e.g. the pion decay constant or the chiral condensate, is well reproduced byusing reasonable values for the gauge coupling constantand the QeD scale parameter in our case. (On thecontrary, almost all studies have not been able to reproduce the enough amount of the dynamical chiralsymmetry breaking, unless a large gauge-coupling constant and a large QCD scale parameter are used. 5))
By extrapolating the dynamical mass to the time-likeregion, we find the absence of the physical poles in
the quark propagator. Hence the confinement for lightquarks is also shown as in the case of heavy quarks.
References
1) T. Suzuki: Prog. Theor. Phys., 80, 929 (1988); 81 , 752(1989).
2) G. 'tHooft: Nucl. Phys., B190, 455 (1981).
3) L. I. Unger: Phys. Rev., D48, 3319 (1993).
4) H. Suganuma and T. Tatsumi: Prog. Theor. Phys., 90,
379 (1993).
5) T. Kugo and M. Mitchard: Phys. Lett., B286, 335(1992).

RIKEN Accel. Prog. Rep. 27 (1993)

First-Order Phase Transition with Global
Z3 and Z4 Symmetryt
S.Ohta[quantum chromo dynamics , Potts model, first-order phase transition.]
Numerical calculation of pure-gauge lattice quantum
chromo dynamics (QCD) shows there is a weak firstorder phase transition at a finite temperature. It ischaracterized by the global Z3 symmetry of Polyakovlines and separates a low-temperature, color-confining
and Z3-disordered phase and a high-temperature,color-non-confining and Z3-ordered phase. The existence of a first-order phase transition and its weakness
are common to the systems with the global Z3 symmetry such as the three-state Potts model. This work
explains this weakness: 1- 5 )In the ordered phase, one of the three Z3 spins isfavored and dominates the volume. However, near the
first-order phase transition, the other two Z3 spins mix
significantly into the system. In the three-state Potts
model example, only about 60% of the volume is covered by the favored spin and the remaining 40% isevenly split between the two non-favored spins. These
non-favored spins distribute in such a way that theirneighborhoods are disordered, i.e. domains of disordered phase are mixed into the ordered phase. Suchmixing leads to a small latent heat and weak phasetransition.
Can we understand such mixing of disordered domains into the ordered phase? The two-point correlation functions , defined as the probability to find a pairof spin i and j separated by the distance r , provide theanswer. The connected part of the correlation shows
how the two spins interact: positive (or negative) connected part means attractive (or repulsive) interaction.
It is found that most of the correlation functions aremonotonous in the range r , either decreasing towards
zero from above or increasing towards zero from below.
Their asymptotic behavior is well described by singlecomponent Yukawa forms , aexp( -mr)/r, in both ordered and disordered phases. A typical value of thecorrelation mass m near the phase transition is about
0.18, in accord with cluster sizes of several lattice spacings.
The only exception is the correlation between thetwo different non-favored spins in the ordered phase,
which seems to have short-range repulsive and longer-

range attractive components. The longer range should
agree with the longest of the other correlation lengths,
but is hard to confirm numerically. What is interestingis that their sum, the total connected correlation, is attractive in the relevant middle range of several latticespacings and changes very slowly compared with theother correlation lengths. Indeed because this middlerange attraction lasts beyond the other correlations, its
accumulated effect is at least comparable with thoseof the others and perhaps larger. Thus neighborhoodsof the non-favored spins become disordered. This isalso consistent with a vanishingly small surface tension at the ordered-disordered phase boundary which
forbids formation of any spherical or convex cluster oflike spins with a finite volume. Another calculationof mine suggests that the same mechanism works inpure-gauge lattice QeD thermodynamics. 4 ,5)Is this middle-range attraction unique to the systems
with the global Z3 symmetry? My numerical calculation of the two-point correlation functions in the fourstate Potts model suggests it is. The model is governedby the global Z4 symmetry, and has much stronger
first-order phase transition separating ordered and disordered phases. In the ordered phase, the correlation
among the different non-favored spins shows the samecombination of short-range repulsion and longer-range
attraction. But the sum dies out much more rapidly,
within the ranges of the other correlations functions. 6 )References
1) S. Ohta: Proc. Int . Symp. on Lattice '92, Amsterdam,
1992, eds. J . Smit and P. van Baal, Nucl. Phys. B ,(Proc. Suppl.) , 30, 842 (1993).
2) S. Ohta: Proc. Int. Symp. on Computing in High Energy Physics '92 , Annecy, 1992, eds. C. Verkerk and W.
Wojcik, CERN Report, CERN, 92-07, 361 (1992) .
3) S. Ohta: RIKEN Accel. Prog. Rep. , 26 , 58 (1992).
4) S. Ohta: 48th Ann. Meet. Phys. Soc. Jpn., Sendai,Mar./ Apr. (1993).
5) S. Ohta: preprint RIKEN-AF-NP-154; submitted for
publication on Phys. Rev. Lett.
6) S. Ohta: Proc. Int. Symp. on Lattice '93, Dallas, Oct.,
1993, Nucl. Phys. B (Proc. Suppl.) to be published.

This work was supported in part by Parallel Computing
Research Facility, Fujitsu Laboratory.

29

RIKEN Accel. Prog. Rep. 27 (1993)

Study ofQ

Decays Following 40 Ar Bombardment on 238U

T. Nomura, M. Wad a , N. Ikeda, S. Kubono, 1. Katayama, Y. Pu, K. Morita, A. Yoshida, M. Kurokawa,T. Motobayashi, H. Murakami, Y. Nagai, H. Kudo, K. Sueki, M. Tanikawa,* 1. Nishinaka,
H. Nakahara, T. Shinozuka, M. Fujioka, H. Miyatake, Y. Fujita, T. Shimoda, and K. Tsukada**
NUCLEAR REACTION, 238U(40 Ar, a2n), E = 5.1 MeV lu; measured re'a ction products,[ a decays, spontaneous fission, time and position correlations; gas-filled separator.
We performed an experiment on the 238U(40 Ar,axn) reaction using the RIKEN gas-filled separator(GARIS) to collect reaction products recoiling out of athin target of 238U. Their velocities and energies were
measured by a time-of-flight system and a positionsensitive detector (PSD) placed before and at the focal plane of GARIS , respectively. Subsequent a decays
and spontaneous fissions (SF) were also measured withthe same PSD. The pulsed beam having the time structure of 10 ms beam-on and 10 ms beam-off was used.
Details of the experimental set-up have been describedin Ref. 1.
Based on the analysis of the time- and positioncorrelations as shown in Fig. 1, we have found a few
a-decay events which have the following features: (1)a-decay energy is 9.37±0.05 MeV; (2) they took place
within 1 s after the recoil nuclei reached the PSD; (3)a few SF events occurred later at the same PSD position. These features are consistent with the theoreticalprediction of decay properties of the yet unidentified
nucleus 272Hs, which was probably produced in the(40 Ar, a2n) reaction. However, its assignment is still
indefinite because we are unable to find the expecteda-decay of its daughter nucleus (2 68 Unh) because of its
long half-life which is predicted to be around 1 h.
Improvement of the experimental set-up, such asthat of position resolution of the PSD , is now III
progress.

* Dept . of Chemistry, Univ. of Tokyo** JAERI
30

1

30
c

::g

20

CI

Singles
Correlated within 1 s

.~

>- 10
9.5

9.75

average

accidental

~

rate

~

9.75
Fig. 1. (Upper) Singles and correlated a-decay spectra
taken during the beam-off period of the pulsed beam.
Only the heavy nuclei (HN) having the measured energies of less than 9 MeV are included in the HN-acorrelations. (Lower) Ratios of the correlated events tosingles events.

References
1) T. Nomura et al.:(1992) .

RIKEN Accel. Prog. Rep., 26, 9

RIKEN Accel. Prog. Rep. 27 (1993)

Production of High-Spin Isomer Beam
T. Morikawa, Y. Gono, E. Ideguchi, A. Ferragut, Y. Zhang, T. Murakami, T. Kishida, K. Morita,
A. Yoshida, H. Kumagai, M. Oshima, H. Kusakari, M. Sugawara, M. Ogawa, M. Nakajima,
S. Mitarai , A. Odahara, T. Shizuma, M. Kidera, J. C. Kim, S. J. Chae, and B. J. Min
Nuclear reactions,24Mge36Xe,a9n)147Gd, 24Mge36Xe,lln)149Dy, 24Mge36Xe,10n)150Dy,[ Ep = 9 MeV lu, Recoil Separator, High-Spin Isomer Beams.
We have developed a new experimental technique
by utilizing the high-spin isomer beams produced via
fusion-evaporation reactions. As reported in Refs. 1
and 2, it is possible to produce, via Xe-induced reactions of inverse kinematics, secondary beams consisting of the high-spin isomer. The unique character of this secondary beam is expected to enable us
to study nuclear high-spin states of exotic condition.
For the moment , the following experiments are being
planned; a) Coulomb excitation for the search of offyrast collective states built on the high-spin isomer. b)
Secondary-fusion reactions for the efficient productionof very high-spin states.
Since the cross section of the primary reaction isan order of 10 2 mb, the intensity of the secondary
beam is very small as compared with that of the primary beam. For the utilization of the high-spin isomerbeams for ,-ray spectroscopy, one needs the beam intensity of > 105 pps at least. In the beginning stage,l)we have started with the beam-transport system withfilling gases for charge equilibration. With this system, however, we could get the high-spin isomer beamof at most rv 10 4 pps. This limitation came from boththe poor transmission of rv 10% and the limit of the
primary beam stably available below a few pnA.
In order to improve the transmission, we tried a new
system without filling gases, since the numerical calculations of the beam optics predicted the transmission
efficiency of rv 25% for the vacuum system by picking
up the most probable three charge states. This predicted value is twice as large as the transmission for
the gas-filled system.
As illustrated in Fig. 1, the new system has two focal planes, F1 and F2. A 3.6 mg/cm2 24Mg target at
FO was bombarded by the primary beam of 9 MeV I u
136Xe delivered from RIKEN Ring Cyclotron. The
HP-Geprimary-beam intensity at FO could be increased up to
rv 10 pnA by the improvement in the RILAC injection
system; in order to keep up-with the large beam current, a new type of carbon stripper foil was used in the
RILAC. The secondary beams of reaction products,
mainly 147 Gd, 149Dy, and 150Dy, were electromagnetically separated from the primary beam, and focusedon the PPAC at Fl. A slit system just upstream of
Fl was used for the elimination of both the primarybeam and the stray beam. The reaction products werefocused again by Q3 and Q4, and finally collected on
the F2-focal plane where a plastic scintillator served
as a catcher. A HP-Ge detector was set close to thecatcher to detect the , rays emitted from the reaction
products.
Optimization of the parameter setting for the magnets was made by monitoring a) the beam profile on the
F1-PPAC, b) TOF spectrum between F1 and F2 andc) the ,-ray yield at F2. We obtained the best resultswith the parameters for the Bp value of 147Gd 50+
charge-state which corresponds to the fully stripped
xenon ions. By using the catcher technique, we measured the transmission efficiency between FO and F2
as well as the beam intensity at F2. As summarizedin Table 1, the transmission of 20- 30% was obtained
for the reaction products of X n channel, while the achannel marked a considerable drop of the transmission. This was due to the difference of angular spreadcaused by the particle emission. For 150Dy produced
via IOn channel, the intensity of 7 x 10 4 pps at F2 wasrealized with the primary beam intensity of rv 4 pnA.
In addition, the beam-spot size was much reduced to
10rv15 mm</> as compared with 30rv40 mm</> of the gasfilled system.
Table 1. Transmission efficiency € of the secondary beams
with 147 Gd q = 50+ setting. The primary 136Xe23+
beam was 9 MeV /u and 90 nA.
Nuclide
14/Gd. .r,.

1:7'81E1 C-COURSE at
RRC
Fig. 1. Layout of the high-spin isomer beam facility at
RIKEN RRC.

149Dy
150Dy

a9n
lIn
IOn

FO
5.9x 104 pps
1.6x 104 pps
2.2x 105 pps

F2
1.2x103 pps
2.8x 103 pps
7.0 x 104 pps

€

2%
18%
32%

References
1) Y. Gono et al.: RIKEN Accel. Prog. Rep., 26, 12 (1992).
2) Y. Gono et al.: Nucl. Phys., A557, 341c (1993) .

31

RIKEN Accel. Prog. Rep. 27 (1993)

High-Spin States of 144Pm
Y. Zhang, Y. Gono, A. Ferragut, T. Morikawa, K. Morita, A. Yoshida, H. Kumagai,
M. Oshima, H. Kusakari, M. Sugawara, M. Ogawa, K. Furuno,* T. Komatsubara,*
J. Mukai,* J. Lu,* J. C. Kim, S. J. Chae, B. J. Min, and T. Murakami
NUCLEAR REACTIONS 14N(136Xe,6n)144Pm, 6.5 MeV lu, 138Ba(lOB,4n)144Pm,
42.5- 55 MeV; Measured EI" II" ,,-coin, Excitation function, II' (0).
In a series of experiments searching for high-spin isomers in N = 82 region, a new isomer of a half life
T 1/ 2 rv 2.7 J-LS with a probable spin value of 2Th was
found in 144Pm.1) Although a tentative decay schemeof this isomer was already reported,2) a revised level
scheme, which has been significantly extended, is givenin this report.
Two experiments were performed. A nucleus 144Pm
was produced through a reaction 14N(136Xe,6n)144Pm
at a beam energy of 8.5 MeV lu which was provided
by RIKEN Ring Cyclotron. Recoiled reaction products were collected on a catcher which was placed 6
m down stream from a target position. This distancecorresponds to about 200 ns flight time. Gamma rays
were detected by four HPGe detectors with BGO antiCompton shields. ,,-coincidence data were used toconstruct the level scheme.
An excitation function and ,-ray anisotropy were
measured by using a reaction 138Ba(lOB,4n)144Pm
with beam energies ranging from 42.5 to 55 MeV
at Tandem Laboratory of Tsukuba University. The
results of this experiments were also reported
previously. 2)
Combining these experimental results, an extended
level scheme of 144Pm is proposed as shown in Fig. 1.
Recently Glasmacher et a1. 3) reported high spin statesof 144Pm studied by the 130Tee9F,5n)144Pm reaction.
They observed the levels up to the spin 20h state at
5.85 MeV. Most of the level structure is consistent with
our results. However we could extend the level scheme
up to the spin (2Th) state at 8.60 MeV.
In this level scheme, an 85.5 keV , ray is placed
to deexcite the isomeric state. Although this kind of
low energy transition often causes isomerism, no suchcase has been observed in high-spin isomers of N = 83
isotones, 145Sm, 147 Gd.
Systematic appearance of high-spin isomers at
almost the same excitation energies in N = 83*32

Tandem Accelerator Laboratory, University of Tsukuba

Tin -2.7 ...... 1- (25-35) 1\

855,8596.5'-8511I 5 3 9.1

966 .4

1

413.5

7975

7913

7559
1211.1

1108
759.2
93.5

.r 6348
~6265

-

1146

~
r;: - I<-

t---

~

614
17+

Ilt-)

- 15(-)

396 .5

H
•

469

J 451

2990
620

12(-)
2270 - 11198

1705

397

II--

-

1156

110
446
1459
22

574

1
I

1

11

505

11+

1

735

.285

Is+-' I=-- r 3906 .1
3 19

-

1

430

t--

14+

3795 .7'- 3729 .5
3410.2

634

13+

-.356

3060.6
r 2775 .3~ 2668 .7231~ . 91038.310+4718
4329 .2

.23

367
864

f812

l~

219

1546

1935

II--

608

1161

10+

-

~ ~ ~7II-14(-)

2072

890

co

H71.8

.4

433.5

I 608.5

1'281.9. . 326.5

1699

T3H .5___ 17 1.8. . 23204

1:~Pm83
Fig. 1. Level scheme of 144Pm.

isotones suggests that they originate from similar
configurations. Probable configuration of the isomer of 144Pm at 8.6 MeV may be obtained as[7r{ (h u / 2)2d5/ 2h5/2+, v{ f7 /2h9/2i13/2h9/2+ 127+ basedon the deformed independent particle mode1. 4)

References
1) T. Murakami et al.: Z. Phys. , A345, 123 (1993) .
2) Y. H. Zhang et al.: RIKEN Aced Prog. Rep., 25, 49(1991).
3) T. Glasmacher et al.: Z- Phys., A345, 119 (1993).
4) K. Matsuyanagi and H. Sagawa: Private communication.

RIKEN Accel. Prog. Rep. 27 (1993)

High-Spin States of 145Sm
A. Odahara, Y. Gono, s. Mitarai, E. Ideguchi, M. Kidera, M. Shibata, T. Morikawa, K. Morita,
A. Yoshida, H. Kumagai, A. Ferragut, Y. Zhang, M. Oshima, H. Kusakari, M. Sugawara,
M. Ogawa, J. C. Kim, S. J. Chae, B. J. Min, and T. Murakami
NUCLEAR REACTIONS 160e36Xe,7n)145Sm, 7.5 MeV lu, 2oNee36Xe,a7n)145Sm, ]8.5 MeV lu, 139LaeOB,4n)145Sm, 47 MeV, 138Bae3C,6n)145Sm, 95 MeV; Measured[ EI" II" II' (8), /,/,-coin, Particle-/' coin, TI'-RF·
A new high-spin isomer was found in 145Sm using
the 160(l36Xe,7n)145Sm reaction at the beam energyof 7.5 MeV lu.I) To construct a decay scheme of theisomeric state, a /,/,-coincidence measurement was carried out by using the 2oNee36Xe,a7n)145Sm reaction
at the beam energy of 8.5 MeV lu. The Xe beam wasprovided by RIKEN Ring Cyclotron. Since the decay
scheme is too complicated to construct based solely
on these data, the additional experiments were performed by using 5 or 6 sets of RIKEN BGOACS's
and Tandem accelerators of Kyushu University andJapan Atomic Energy Research Institute. The 47 MeVlOB beam was used at Kyushu University to make the139LaeOB,4n)145Sm reaction. The 95 MeV 13C beam
was used to induce the 138Bae3C,6n)145Sm reaction.
Analyzing all these data, an extended decay schemeof the high-spin isomer of 145Sm has been constructed as given in Fig. 1. The configuration of
the isomer may be the same as that of 147 Gd, 2) i.e.
[7r{ (h u / 2)2ho+, v{ (h9/2)-li13/2f7/2h9/2+ ]49/2+. This
assign-ment may be supported by the facts that theexcitation energies of the isomers of 145Sm and 147 Gd
are about 8.5 MeV and the numbers of transitions de-:exciting these isomers are roughly 50. The level schemeof 145Sm was reported previously up to the 25/2+ stateat the excitation energy of 3.48 MeV. 3) Although data
analyses of the present results are still in progress, theangular distribution data indicated the spin assignments which are consistent with the reported ones. 3)
Interesting observation in the decay of the high-spin
isomer is that there are some missing /,-ray intensities
between about 3 and 6 Me V in the decay scheme. This
fact was already pointed out in case of 147Gd.4) However the same ,w as observed in 144Pm5) and also in945~----..I.I.II.L..l...--.,..--~--1I05

13/2+

1105
7 1 2 _ - - - -..1....-- - - -

145

Sm

Fig. 1. Level scheme of 145Sm.

1820S.6) So this phenomenon occurs rather commonlyand seems to indicate that the decays of these high-spin
isomers go through non-yrast states in these energy
regions.
References
1) A. Ferragut et al.: J. Phys. Soc. Jpn., 62, 3343 (1993).
2) O. Hausser et al.: Phys. Rev. Lett., 42, 1451 (1979) .
3) M. Piiparinen et al.: Z. Phys., A338, 417 (1991).
4) R. Broda et al.: ibid., A305, 281 (1982).
5) Y. H. Zhang et al.: This report , p. 32.
6) P. Chowdhuryet al.: Nucl. Phys., A485, 136 (1988).

33

RIKEN Accel. Prog. Rep. 27 (1993)

Coincidence Measurements for Neutrons and a Particles
from the Fragmentation of 6He at 800A MeV
K. Yoshida, I. Tanihata, T. Kobayashi, T. Suzuki, S. Shimoura, K. Sugimoto,*
K. Matsuta,* S. Fukuda,* H. Wieman,** W. Christie,** and D. Olson**[NUCLEAR REACTION 6He(C, no:)X, E = 800A MeV; measured momentum distribution.]
Neutrons and 0: particles from the fragmentation of
6He nuclei have been measured simultaneously at 800A
MeV to study the structure of the halo nucleus 6He.
The 6He nucleus is considered as a composite systemwith a core 0: particle and two valence neutrons thatform the halo. Hence, the correlation between the neutron and the 0: particle is expected to have important
information for the structure of the 6He nucleus. 1 )The experiment was carried out at the BEVATRON
at Lawrence Berkeley Laboratory. Ions of 18 0 were accelerated to 800A Me V and irradiated the Be target ofI" in thickness to produce 6He nuclei as the secondary
beam. The secondary beam was purified by using themagnets of the transportation line B42 and was led
to the reaction targets. The remaining contaminationof the beam was identified and rejected by measuring
the energy loss of a beam nucleus in a thin scintillator.
The trajectory of a beam nucleus was also measured
by three MWPC detectors. The reaction target was acarbon block of 5 g/ cm 2 thickness. Charged particles
from the fragmentation reaction of 6He were measured
by a HISS spectrometer and neutrons were detected bya plastic scintillator wall located at 10 m downstreamof the reaction target.
The transverse-momentum distributions of neutrons
and a particles show the two-Gaussian shape. The
widths of the Gaussians are 40 and 110 Me V / c.
Both widths are the same for neutrons and 0: particles. However, the distribution of neutrons has
a larger contribution from the narrow component
than that of 0: particles. The widths for 0: particles are consistent with the value obtained fromthe inclusive measurement at 400A MeV. 2 ) In Fig.
1 shown is the momentum correlation function between the neutron and the 0: particle. The correlation
function was deduced as Y(Pn , Pa )/ {J Y(Pn , Pa)dPn ·J Y(Pn , Pa)dPa }, where Y(Pn , Pa) is the coincidence

*
**
34

Osaka Univ.
Lawrence Berkeley Laboratory, U.S.A.

yield of the neutron and the 0: particle at momentums
Pn and Pa, respectively. As seen in Fig. 1, the prominent feature of the correlation function is the two broadlines running parallel from the lower left to the upper right side of Fig. 1. A calculation with a simple
kinematical model revealed that the lines can be reproduced with the assumption of the formation of the
5He ground state. Thus the structure observed in thecorrelation function is due to the sequential decay of
6He through the 5He ground state and does not reflect
the correlation between the neutron and the 0: particlein 6He.
20 O. 010 2
100 . 0

10

~
~

~

0.0

C
0..

- 100.0-20 0 .0 -tr-=.,........,.......,.....;~-r---t---.--,L;----,-----\Ic.I.--,....,-r-r--r--.--,'-200.0-100 .00 .0

100 . 0200 .0P o. (MeV Ie)

Fig. 1. Two dimensional plot of the correlation functionof neutrons and Q partilces from the fragmentation reaction of 6He.

References
1) M. V. Zhukov, L. V. Chulkov, B. V. Danilin, and A. A.
Korsheninnikov: Nucl. Phys., A533, 428 (1991).
2) T. Kobayashi: ibid., A538, 343c (1992).

RIKEN Accel. Prog. Rep. 27 (1993)

Measurement of Light Charged Particle Emission in Coincidencewith Fission Fragments from 84Kr + 27 AI, ,56 Fe at IO.5A MeV
Y. Futami, Y. Honjo, S. Tomita, T. Mizota, K. Yuasa-Nakagawa, H. Toyokawa, K. Furut aka , K. Matsuda,
Y . Akeboshi, J. Kasagi, T. Nakagawa, S. M. Lee, and W. Shen*
NUCLEAR REACTION 84Kr + 27 AI, 84Kr + 56Fe, E( 84 Kr) = 10.5 MeV/nucleon; measured light[ charged particle energy and angular distributions in coincidence with fission-like fragment.
In a previous work,l) we have studied the decay
mechanisms of complex fragments from a hot compound nucleus
In, E* ~ 200 MeV). These results(Z distribution of fragments , missing charge , etc. )2)
were compared with the theoretical calculations of the
Extended Hauser-Feshbach method which considers all
possible full statistical open channels giving binary divisions from the light particle emission to symmetric
one in the highly excited compound nucleus. 3 ) It was
concluded that the fission decays were dominant in
the first-step calculation followed by post-evaporation.
Data of the missing charges that correspond to total
evaporated charged particles from a composite systemwere well reproduced by the calculations. The contribution to the predicted missing charge from prescission charged particle evaporation was calculated tobe small compared to that from post-scission evaporation. Though the calculated results seem to be consistent with the observed data, there is a strong assumption embedded: the fission and the evaporation
can compete equally even in the highly excited stateof compound nucleus.
To verify this assumption and conclusion more directly, we performed a measurement of light charged
particle multiplicity of pre- and post-scission evaporation. Multiplicity of protons and a particles wasmeasured with coincident fission-like fragments for thereactions of 84Kr + 27AI, 84Kr + 56Fe at the incident energy of 10.5A MeV. The experiments were performed using the large cylindrical scattering chamber
ASCHRA 4) of RIKEN Ring Cyclotron Facility. Heavy
Fragments were detected by a time of flight counter
telescope which consists of two channel-plate detectors and followed by an Si detector. This detection
system was set at 10° with respect to the beam di. rection. Coincident light charged particles were observed using the 37r multi detector system that consists of 120 phoswich detectors and covers the angular range between 10° and 160°. The phoswich detector consists of thin plastic and thick BaF 2 scintillatorsthat have good time response. 5) For each phoswich detector, the pulse shape discrimination technique wasused, and it allowed us to identify ,-rays, neutrons,
protons and a particles. To separate contributions oflight particles from either prior to fission or after scission (fragment emission), it is quite powerful to use*

Institute of Nuclear Research Academia Sinica, P. R. China

2 G
'
10',
E
• 0 J
- 90 '
0~!

:uo
20 < AF.F. < 40

40 < AF .F < 60

ell

10

2

° ..,",,' ....... ,.,

0

0

50

1

7''"
..

100

_

-- " .. " ' ..

40

80

120

~[2\[~'12\~:
20

40

60

60

20

40

60

60

Ener gy [MeV]Fig. 1. Coincidence spectra (histograms) for Q particle
from the reaction 1O.5A MeV 84Kr + 27 Al overlaid by
3-source calculations (curves). The fitted post-scission,
pre-scission and total spectra are shown by dashed, thincontinuous and thick continuous lines respectively.

the correlation method between fission fragments andlight charged particles using the characteristic difference of kinematics and source nature. 6,7) Energy spectra of protons and a particles were analyzed with a
3-source calculation 7) shown in Fig. 1. A pre-scission
component from compound system and post-scission
components from detected and undetected fragmentsof the charged particle multiplicity were extracted.
Contrary to the expectation, the experimental valueof pre-scission charge multiplicity is 10 times as large
as that calculated by the statistical model (GEMINI
code8)) . This value corresponds to about 75% of total charge multiplicity. It may suggest that there is ahindrance effect of channels going to fission decays atfirst-step in the decay from a compound nucleus withhigh excitation energy and/or large angular momentum.
References
1) T. Nakagawa et al.: RIKEN Accel. Prog. Rep. , 26, 14(1992).
2) K. Yuasa-Nakagawa et al.: Phys. Lett., B283, 185(1992).
3) T. Matsuse et al.: Proc. Int. Symp. Nikko'91 (Nikko,
June 1991) AlP Conf. Proc. , 250, 100 (1991).
4) T. Nakagawa et al.: RIKEN Accel. Prog. Rep., 22, 147(1988).
5) Y. Futami et al.: Nucl. Instr. Meth., A326, 513 (1993).
6) R. Laceyet al.: Phys. Rev., C37, 2540 (1988).
7) L. Schad et al.: Z. Phys., A318, 179 (1984).
8) R. J. Charity et al.: Nucl. Phys., A483 , 371 (1988).
35

RIKEN Accel. Prog. Rep. 27 (1993)

Neutron Emission in the 40 Ar + 116Sn Reactions
at EI A == 30, 37 MeV lu
K. Furutaka, K. Yoshida, A. Yajima,* Y. Akeboshi ,** K. Matsuda, T. Murakami, J. Kasagi,
T. Nakagawa, K. Yuasa-Nakagawa, Y. Futami, A. Galonsky, and G. Bizard
NUCLEAR REACTIONS: 40 Ar + 116Sn at Ej A = 30, 36.4 MeV; measured[ neutron energy spectra and angular distributions; moving source analysis.
To study the properties of highly excited nuclei , wehave measured energy spectra of neutrons emitted in
40Ar + 116Sn reactions at Ej A = 30 and 36.4 MeV ju.
Self-supporting foil of 116Sn (about 1 mgjcm 2 ) was irradiated with 30 and 36.4 MeV ju 40Ar beams of about
15 enA served from the RIKEN Ring Cyclotron. Neutrons emitted in these reactions were detected in coincidence with heavy evaporation residues (ER) , with 22
liquid scintillation counters placed between 30 and 155
deg. with respect to the beam axis. Energies of neutron were measured through the Time-of-flight(TOF)
method. TOF lengths ranged from 0.8 m to 2.4 m.
Overall time resolution was about 1.5 ns (FWHM) for
prompt 1'-rays. Heavy residues were detected with 4
stacks of MCP-MCP-Si detector array and mass AER
and velocity VER of evaporation residues were deduced.
In off-line analysis, events were divided into 8 groups
according to mass and velocity of heavy residues (2mass bins x 4 velocity bins), and double-differential
neutron energy spectra were obtained for each region.
The obtained spectra were analysed with the moving source model and multiplicity M , temperature parameter T, and kinetic energy per nucleon C were deduced. In the model, neutrons were assumed to be
emitted isotropically from the sources. Two emission
sources were needed to reproduce the spectra. One isa pre-equilibrium-like source whose velocity is roughly
a half of the one for beam. The other is an equilibrium source moving with similar velocity to VER. Parameters obtained in the fitting are plotted in Fig. 1
against R = VERjVFMT, where V FMT is the velocity
coresponding to the full momentum transfer. As seenin the figure, all parameters other than cpre are increas-*

Toshiba Electric, Co.

** Present Address: Mitsubishi Electric, Co.
36

E/ A= 30 MeV / u

E/ A=36.4 MeV / u

>' 12

~ 10

-:

8

J- 6

4 8H++~1+~H1++~~MH~~1+~~++H

>' 18

~ 16
-: 14
f-~ 12

10 RH4+~1+~H1++~~MH~+MH+~~++H
5

~

~

4
3
2 ~++MH~~~++MH~H1++MH~+M1+~H

>'
3
Q)

1

go

14
12

~~

10
8

6 ~~~~~~~~~~~~~~~~~
0 .2
0.4
0 .6
0.8
0.2
0 .4
0.6
0.8
V re./ VFMT
V re.l V FIIT

Fig.
Teq

1.

Parameters obtained by the fit:

Meq

(Mpre ) ,(Tpre ), and Ce q (c pre ) are multiplicity, temperatureparameter, and kinetic energy per nucleon for an equilibrium (pre-equilibrium like) souce, respectively.

ing functions of R. cpre is almost independent of R.
No sizable increase is observed for Meq by increasing
incident energy, although apparent temperature Teq isincreased. Detailed analyses are now under way.

RIKEN Accel. Prog. Rep. 27 (1993)

Charged Particle Emission in 40 Ar + natNi Reactions
at E/A == 30 MeV
K. Matsuda, Y. Akeboshi, K. Furut aka , J. Kasagi, T. Nakagawa,K. Yuasa-Nakagawa, Y. Futami, and K. Yoshida
NUCLEAR REACTIONS: 40 Ar + natNi at E/ A = 30 MeV; measured charged particle[ energy spectra and angular distributions; moving source analysis.

Properties of very hot nuclei have been studied
through the heavy ion fusion reactions in intermediateenergy regions. In order to investigate the maximum
excitation energy and the highest temperature that canbe sustained by a nucleus, we measured charged particles in coincidence with heavy evaporation residues
in the 40 Ar + natNi reaction at an incident energy of
E/A = 30 MeV.
The experiment was performed in a large cylindri- ·cal scattering chamber ASCHRA and the beam wasprovided by RIKEN Ring Cyclotron. We constructed
a 37r detector system consisting of 120 Phoswich Detectors (BaF 2 + Plastic scintillator) in order to detectand identify charged particles, neutrons and g-rays by
this detector system. I) This system gives us a unique

10 'O. 45<R<0 . 65

1

method to determine the e?Ccitation energy of fusion
products. The excitation energies can be extracted as asum of kinetic energies of whole particles emitted fromthe excited nucleus in the reaction. The fusion residues
were detected by four sets of telescopes placed at 10
degrees with respect to the beam axis. Each telescopeconsisted of two channel-plate detectors (CPD) anda silicon detector (SSD). The mass and the velocityof the residues were deduced from the time of flightand the total kinetic energies of residues which were
measured by CPD 's and SSD, respectively.
In the analysis, events were grouped into eight binsaccording to the mass of residues and the ratio <R>
between the residue velocities and those for the complete fusion residues. Figure 1 shows the obtained pro-O. 65<R<0. 85

O. 85<R<1. 00

10 6
10 5
10 4

~

10

3

~

10

2

.~

10

;;
~

;a,
'J::

1

10°

'3

::E

10- 1

---

10 - 2

~x.
-'~

10- 3
10- 4
10 -5
20

40

60

80

20

40

60

80

20

40

60

80

100

Energy (MeV)

Fig. 1. Proton energy spectra observed in coincidence with residues in different velocities given by R and of
mass = 45- 60. Solid lines represent a moving-source fit with two sources, and dashed lines are contributionsof pre-equilibrium emission. Note the change of ordinate scale by a factor of 10.

ton spectra in coincidence with residues in different velocities given by R and of mass = 45- 60. The energy
spectra were analyzed with the moving-source model.
We assumed two sources, the fusion equilibrium source
and the pre-equilibrium source, in this model since thespectra had two components and were not reproducedwith one source. The results of moving-source fitswere shown in Fig. 1 with solid lines. As seen, theobserved spectra were well reproduced by the model.
Further analysis is now in progress.
References
1) Y. Futami et al.: Nucl. Instrum. Methods Phys. Res.,
A326, 513 (1993).

37

RIKEN Accel. Prog. Rep. 27 (1993)

Spin-Isospin Excitation in sd-Shell Nuclei Studiedby (d, 2He) Reactions
T. Niizeki, H. Ohnuma, T. Yamamoto, K. Katoh, T. Yamashita, H. Okamura, H. Sakai,
S. Ishida, N. Sakamoto, H. Otsu, T. Wakasa, T. Uesaka, T. Ichihara, H. Orihara,
H. Toyokawa, S. Kato, S. Kubono, and M. Yosoi[NUCLEAR REACTION 28Si, 26Mg(d,2He), Ed = 270 MeV.]
Gamow-Teller (GT) like transitions dominate smallangle spectra obtained in intermediate (p,n) reactions.
The GT strength deduced from these reactions isroughly 2/3 of what one would expect from the sumrule or from the most reliable shell-model calculations.
The origin of such "missing strength" is the subjectof many theoretical and experimental investigations atpresent. In order to obtain the GT strength corresponding to 13+ decays, it is necessary to study charge
exchange reactions which increase T z by one unit.
The (d, 2He) reaction is a unique tool for the studyof spin-isospin excitation modes of nuclei, the GT
strength in 13+ channel in particular, since 2He particles are correlated proton pairs coupled to the singlet
S state while the incident deuteron is in the triplet
S state (with a small amount of triplet D mixture).
Therefore, transitions with spin change of one unit isautomatically selected, as well as the isospin change, inthis reaction. The development of a large acceptancemagnetic spectrometer SMART 1 ) at RIKEN has madeit possible to study intermediate energy (d,2He) reactions with good efficiency. It has been confirmed 2) thatthe (d, 2He) reactions on p-sheU nuclei indeed excite selectively the GT-like states at small angles, and thatthe 0° (d,2He) cross sections for such states are proportional to the G T strengths known from the ,B-decay
measurements.
We have extended our study to sd-shell nuclei, andinvestigated the (d,2He) reactions on 28Si and 26Mg.
A comparison of the 28Si(d,2He)28 Al reaction with the28Si(p,n)28p reaction will enable us to further establish
the feasibility of using (d, 2He) reactions in the study of
GT strength distributions in this mass region. Virtually nothing is known at present about 26N a, the residual nucleus of the 26Mg( d, 2He) reaction. A comparisonof the spin strength distribution in such neutron-richnuclei with shell model predictions will give us an important clue to explore the origin of missing strength
problem.
A 270-MeV deuteron beam from the RIKEN Ring
Cyclotron was led to the target located at the pivot of
the beam swinger system in the E4 counting room.
The targets were self-supporting foil of 50 mg/cm 2
thick natSi and 2.6 mg/cm2 thick 26Mg enriched to99%. The outgoing 2He .particles were analyzed byusing a large solid angle magnetic spectrometer withwide momentum acceptance. Correlated proton pairs

38

were detected in coincidence after the first dipole ofthe spectrometer. Two sets of multi-wire drift chambers (MWDC), each having six (X-X'-U-U'-V-V') wire
planes, and two sets of scintillation counter hodoscopes
were used to identify protons and determine their trajectories. We have changed the counter gas for MWDC
from Ar(70%) + iso-C 4 H lO (30%) mixture previously
used to Ne(20%) + C 2H6(80%) mixture, and a helium
bag was inserted between the exit window of the spectrometer and the counters, to reduce multiple scattering effects.
A sample spectrum from the 28Si(d,2He) reaction isshown in Fig. la. A strong peak at 2.0 MeV in 28 Al
corresponds to the mirror state of the 2.1 MeV state in
28p observed in the 28Si(p,n)28p reaction. The latteris reported3 ) to have the GT strength B(GT) of 0.92.
The (d, 2He) cross section at 0° observed in the present
experiment is consistent with this B(GT) value. A
0° spectrum obtained for the 26Mg( d, 2He) reaction iscompared in Fig. lb with the B(GT) strength distribution calculated with the shell-model wave functions. 4 )The predicted distributions seem to be in good agreement with the present data. Further analysis of theexperimental data is under way.

2500 ~~-2.20~
M'V -l+~~--~ 4oo ~~~O.O8M-CV ~I+--~~a~> 2000b

28Si (d, l-Ier AI

~

300

~

200

~ 2\tg (d, 2Hd 6Na<'! 1500§ 1000

til

0

u

3

500

100

2

o

0
2Q - 10

o~

Id

-5

0

5

\0

15

Excitation Energy in 28A1 (MeV)

~

-5

0

5

10

15

Excitation Energy in 2~a (MeV )Fig. 1. Energy spectra of 2He obtained at 0° for the28Si(d,2He)28 Al and 26Mg(d,2He)26Na reactions at Ed= 270 MeV. In Fig. 1b also shown the B(GT) distribution calculated from the shell-model wave function.

References
1) H. Ohnuma et al.: RIKEN Accel. Prog. Rep., 21, 164(1987); 22, 148 (1988); 24, 108 (1990).
2) H. Ohnuma et al.: Phys. Rev., C47, 648 (1993).
3) B. A. Anderson et al.: ibid., C43, 50 (1991).
4) B. A. Brown et al.: Program OXBASH (unpublished).

RIKEN Accel. Prog. Rep. 27 (1993)

Measurement of Analyzing Powers for the d + p
Elastic Scattering at Ed = 270 MeV
N. Sakamoto, S. Ishida, H. Sakai, H. Okamura, H. Otsu, Y. Satou, T. Uesaka,
T. Wakasa, K. Katoh, T. Niizeki, T. Yamashita, and K. Hatanaka[NUCLEAR REACTIONS: d + p at Ed = 270 MeV; measured analyzing powers of A y , Ayy , Axx , Axz']
Complete set of analyzing powers A y , A yy , A xx , andAxz was measured for the d + p elastic scattering at
Ed = 270 MeV. The angular distributions were obtained for the angles of the center of mass system from
57° to 138°. The vector and tensor polarized deuteronbeams were provided by the RIKEN high intensity polarized ion source.
The measurement was carried out by using a scattering chamber installed in the beam transporting lineof the Ring cyclotron. Four plastic scintillation counters (bJ) = 2.3°) were placed at the same angles in thehorizontal (left and right) and vertical (up and down)planes. In order to perform kinematically complete
measurements, other four counters were placed at theangles for the recoil protons.
The target was a sheet of CH 2 with a thickness of
87 /-Lm. The beam intensity on the target was 10- 30
nA.
The tensor analyzing power Axz measurement requires a polarized deuteron beam whose quantization
axis lies in the scattering plane at a definite angle withrespect to the incident beam direction. The spin axis
was rotated into the horizontal plane, about 135° tothe incident beam, by a "Wien-filter system" which is
set at the exit of the ion source.
The beam polarizations were monitored continuously during the experiment by a polarization monitor
system installed at the experimental room E3, downstream of the scattering chamber. Measured polarizations were typically 60- 70% of the ideal values.
The result is shown in Fig. 1. The error bars include
only statistical error. Theoretical analysis is now inprogress.

1.0 -

I

1

1

1

1-'

0.5 -

-

..

Ay 0.0····. ..

-

-0.5 r--1.0 r:-I
1.0 r- I
0.5 rAyy 0.0

-0.5

1

]

]

1-:

1

1

I

1-'

.····

GI
GI

GI_

-

~

-1.0 - I
1.0 - 1

1

]

1

1-;

1

1

1

1-'

-

0.5 -

Axx 0.0

..
.
····

-

-0.5 --1.0 r:-I
1.0 f- I
0.5 r-

GI

1

1

1

]-:

I

I

I

1-

CD

ID

GI

GI
ID

i

-

GI

Axz 0.0--0 .5 f--1.0 r:-I
60

1

1

]-:

80 100 120
8 eM (degree)

1140

Fig. 1. Analyzing powers of the d + p elastic scatteringat Ed = 270 MeV.

39

RIKEN Accel. Prog. Rep. 27 (1993)

Measurements of the Tensor Analyzing Power Axx*
for Deuteron Elastic Scattering from 1 2 C, 40Ca,
and 208Pb at Ed == 270 Me V
T. Uesaka, K. Hatanaka, T. Ichihara, S. Ishida, T. Niizeki, H. Ohnuma, H. Okamura,
H. Otsu, H. Sakai, N. Sakamoto, T. Wakasa, T. Yamamoto, and Y. Yano[NUCLEAR REACTION 12C, 40Ca, and 208Pb(d,d) ; tensor analyzing power.]
We measured the angular distributions of differential
cross sections and Axx* 's for deuteron elastic scattering from 12C , 40Ca, and 208Pb at Ed = 270 MeV usinga polarized deuteron beam from the RIKEN High Intensity Polarized Ion Source. The beam polarization
was measured at the AVF polarimeter and the D-roompolarimeter and found to be about 50% of the maximum value.
Scattered deuterons were analyzed by the spectrograph SMART and detected at the secind focal plane
F2. The detector system consisted of 8 MWDCs andtrigger counters. The angular acceptance of F2 isabout 8 degrees. We measured the angular distributions changing the incident beam angle with respect
to the axis of the Analyzing Magnet by the Beam
Swinger. The present data obtained with 5 separate
Swinger angle settings cover from 5° to 37° in LAB-

angle.
The angular distributions of differential cross sections are plotted as ratio-to-Rutherford in Fig. 1. The
solid curves represent the fit by the optical model calculation. Figure 2 shows the tensor analyzing power
Axx*, which is a combination ofAxx, Ayy (, Azz) , andAxz. (see Table 1)
Because deuteron spin precesses in the Swinger Magnet , the observed analyzing power depends on the
Swinger angle. The error bars include the statisticalerrors and the errors of a beam polarization.

...
Q)

~
0

0 .0
- 0 .2

0...

- 0.4

tlll

-0.6

'N

0.0

c:

~ ><

t

ro. >< - 0.2<D<D!'

<1":

- 0.4

W

d f f
nIt ! I

IPqi

40 Ca

Q)

~0
2

i~ l

or

~t~~mi'lDlDiP ~i I

C: <C

- 0 .60 .0

xxxxXl i- 0 .2-0 .4

I

1i!~~~i mmm I~ID~ ii!f! f
i or IDIDID

208

Pb

t

II

If

- 0 .6
10

20

30

40

8 CM [deg]Fig. 2. Angular distributions of tensor analyzing power
Axx*.

Table 1. Expressions ofAxx* .
10

20

30

40

8 cM [deg]Fig. 1. Angular distributions of cross section for the
deuteron elastic scattering from 12C, 40Ca, and 208Pb
at Ed = 270 MeV. The solid curves are the fits by the
optical model calculation.

40

Swinger angle

Axx*
0.90Axx + 0.030 (Ayy - Azz) - O.13Axz
0.80Axx + 0.056 (Ayy - Azz) - 0.17Axz
0.70Axx + 0.090 (Ayy - Azz) - 0.20Axz
O.56Axx + 0.13 (Ayy - Azz) - 0.24Axz
O.40Axx + 0.17 (Ayy - Azz) - 0.24Axz

RIKEN Accel. Prog. Rep. 27 (1993)( 12 C,12N) Charge-Exchange Reaction at E/ A = 135 MeV
T. Ichihara, T. Niizeki, Y. Fuchi,H. Okamura, H. Ohnuma, M. Hosaka, S. Ishida, K. Katoh, S. Kato,
H. Kawashima, S. Kubono, S. Miyamoto, H. Orihara, N. Sakamoto, S. Takaku, Y. Tajima,
M. Tanaka, H. Toyokawa, T. Uesaka, T. Yamamoto, T. Yamashita, M. Yosoi, and M. Ishihara

Charge-exchange reactions of the (n,p) type (~T z =-1) have recently attracted great interest because of
their implications for astrophysical processes and forthe quenching problem of the Gamow-Teller (GT)strength. Among a variety of charge-exchange reactions, heavy-ion induced reactions at intermediate
energies would afford a unique means to study spinisospin excitations. The applicability of the heavyion exchange reaction to the spectroscopy depends onwhether it occurs via a direct one-step process.
One-step and two-step DWBA calculations showthat in the Ej A > 100 MeV region, a two-step process becomes negligible and a direct charge-exchange
is dominant. 1,2)
The charge-exchange reaction of 12 Ce 2C, 12N) 12B
has been studied at Ej A = 135 MeV using the spectrograph SMART at RIKEN. 3) Figure 1 shows the measured differential cross sections of the 12ce2C,12N)12B
reaction leading to the 12B (1 +) ground state. The differential cross sections of the elastic scattering of 12C
from 12C were also measured to determine the opticalpotential parameters and they are plotted in Fig. 2.
Microscopic one-step DWBA calculations were performed with the code of Lenske et al. 1) by assuming
the double folding model of the one-body transition
density in the shell model and using the effective interaction of Franey and Love. 3 )The solid curve in Fig. 1 shows the result of the
DWBA predictions. An excellent fit has been obtained
for all the angle region. The dashed and dotted curves

2~-~ -~4 --

6

6

10

12

8e~m. (deg)Fig. 2. Observed angular distributions of the 12CC2C,
12C) 12C elastic scattering.

in Fig. 2 show the L = 0 and L = 2 components, respectively. The L = 0 component is mainly excited by
the central part of the effective interaction, while the
L = 2 component is mainly excited by the tensor partof the effective interaction. 2,4)
An intriguing observation in this figure is that the L= 0 component dominates over the L = 2 component.
In particular the ratio of L = 0 to L = 2 is about 6
around 0°. This result differs significantly from that at
EjA = 70 MeV,1 ,2) where the contributions of the twocomponents are comparable around 0° and a major
fraction of the cross section is attributed to the L = 2
component (i.e. from the tensor interaction) for angles
beyond 2°. This can be understood by the increased
nuclear transparency at this energy region. 4 )The study of the 12Ce 2C,12N)12B charge-exchange
reaction at Ej A = 135 MeV shows that the cross sections for the ~J7r = 1+ transition can be quantitatively
reproduced by the one-step DWBA calculation. Thissuggests that the heavy-ion charge-exchange reactions
at this energy is dominantly the one-step process anda good spectroscopic tool for nuclear spin-isospin excitations.
References

Fig. 1. Observed angular distributions of the 12CC2C,
12N)12B reaction.

1) H. Lenske et al.: Phys. Rev. Lett., 1457, 62 (1989).
2) N. Anantaraman et al.: Phys. Rev;, C44, 398 (1991).
3) M. A. Franey and W. G. Love: ibid., C31, 448 (1985).
4) T. Ichihara et al.: Phys. Lett. B, to be published.

41

RIKEN Accel. Prog. Rep. 27 (1993)

Measurement of Quadrupole Moments for the
Neutron-rich Nuclei 14B and 15B
K. Asahi, H. Izumi, H. Ueno, K. Nagata, Y. Hori, H. Okuno, A. Yoshida,
T. Sekine, H. Sato, N. Aoi, G. Liu, M. Adachi, and M. Ishihara
NUCLEAR REACTION 93Nb(180, 14,15B), E/A = 70 MeV /u, spin-polarized[ radioactive beams; measured ,B-NMR frequency; deduced quadrupole moments.
The fragmentation of medium-energy heavy ions has
been shown to be able to produce spin-polarized radioactive nuclear beams,1) and in fact was utilized formeasurements of magnetic moments of several nuclei. 2)
In the present work we have applied this method
to measurements of electric quadrupole moments forneutron-rich nuclei 14B(17l' = 2-, T1 / 2 = 12.8 ms) and15B(17l' = 3/2-, T1/2 = 10.3 ms).
Experimental setup is similar to the previous
experiment,2) except for a part concerning the implantation and rf excitation for NMR. Fragments 14 B or
15B emitted at 3.0° ± 1.0° from an Nb target of 429
mg/cm 2 in thickness were accepted by the RIPS fragment separator. 3) The fragments were implanted in astack of discs of single-crystal Mg placed at the final
focus of the RIPS. An external field Bo = 30.6 mT wasapplied in the z-direction defined normal to the reaction plane. After being stopped at a site in the crystal where an axially symmetric field gradient q wasexerted, the fragment nuclei were exposed to an oscillating magnetic field. The up/down asymmetry of,B-rays emitted from the stopper was observed in orderto detect a spin flip transition induced by NMR.
The energy of a substate m of the nuclear spin I having the electric quadrupole moment eQ and the magnetic dipole moment gJLN1 is given by the first order
perturbation theory as

1

In Fig. 1 the observed ,B-ray up/down ratio with() = 0° is plotted for fragments 14B and 15B, as a func-tion of the assumed value for vQ, or eqQ / h. From
the dip positions the quadrupole coupling constants
were determined to be leqQ(14B)1 = 105.4 ± 1.8 kHz
and leqQ(15B)1 = 134.5 ± 2.7 kHz. Taking the ratios to the 12B result leqQ(12B)1 = 46.55 ± 0.34 kHz
and using the reported values IQ(12B) 1 = 13.21 ± 0.26
mb,4) the quadrupole moments were determined as
IQ(14B)1 = 29.9 ± 1.0 mb and IQ(15B)1 = 38.1 ± 1.3
mb.

1,35

"s in Mg

,Q

1§
~

:::J

130

1.25 '---~~-~~-~~-----'
70
80
90
100
110
120
130
1 40
1.40 .---~-~-~-~---," S in Mg
1.35

1 ,20 '----~~~-~-~-----'
W
100
1M
1~
1~
1~

eqQ/h [kHz)Em = -gJLN Bom +2
eqQ(3cos () - 1) [3 2 - 1(1)]
81(21 _ 1)m+1
where () denotes the angle of the principal axis of the
field gradient relative to the z-axis. The transition
between the states m and m + 1 corresponds to thefrequency V rn ,rn+1 = gJLNBo/h - vQ(3 cos 2 () - 1)(2m +1)/4, where vQ is defined as vQ = 3eqQ/[21(21 - l)h].
For a given vQ value, V rn ,rn+1 for all possible m canbe calculated. In the present experiment, all these 21
different rf fields were simultaneously applied for each
assumed value of vQ.

42

Fig. 1. Up/down ratio of the {3-ray intensity as a functionof the assumed value for eqQ/h , observed for 14B (upper) and 15B (lower) nuclei. The curves are results of
the least-squares fitting with a Lorentzian function.

References
1) K. Asahi et al.: Phys. Lett. , B251 , 488 (1990).
2) H. Okubo et al.: Hyperfine Int., 78, 97 (1993).
3) T. Kubo et al.: Nucl. Instrum. Methods Phys. Res.,
B70, 309 (1992).
4) T. Minamisono et al.: Phys. Rev. Lett., 69, 2058 (1992).

RIKEN Accel. Prog. Rep. 27 (1993)

The Solar Neutrino Production Reaction 7Be(p, ,)8B Studied
by the Coulomb Dissociation Method
N. Iwasa, T. Motobayashi, M. Gai,*! S. Shimoura, T. Delbar,*2 Y. Watanabe,
T. Kubo, N. Inabe, Y. Futami, K. Furut aka , M. Kurokawa, H. Murakami,
Y. Ando, T. Teranishi, K. 1. Harn,*3 Z. Zhao,*4 R. H. France Jr.,*!
T. Nakamura, S. Shirato, J. Z. Ruan (Gen), and M. Ishihara[NUCLEAR REACTION 208Pb(8B,7Be p)208Pb, E = 47 A MeV.]
The low energy cross section for the 7Be(p,I')8B reaction has been studied through the 8B breakup process in the Coulomb field of 208Pb at E(8B) = 47 A
MeV. The cross section at Erel = 0- 20 keV is crucial in predicting the high-energy solar neutrino flux
measured in the experiments of Davis et al.!) and
Kamiokande. 2)
An 8B beam produced by the RIPS facility bombarded a 208Pb target of 50 mg/cm 2 thickness. The
breakup products, 7Be and proton, were detected incoincidence by a tlE-E telescope of 1 m wide and 1
m height, set 5 m from the target with the symmetry
axis along the beam line (Fig. 1). The tlE-counter
consisted of 10 plastic scintillators of 5 mm thickness
and the E-counter consisted of 16 plastic scintillatorsof 6 cm thickness. At the center of the tlE-counter analuminum plate of 15 cm diameter and 4 mm thickness
was settled to stop the beam. A helium-bag was set
between the target and the detector to reduce multiple
scattering and parasitic reactions.
The energies of the proton and 7Be were determinedby the TOF obtained by the signals from the telescope
and a plastic scintillator placed at the second focal
point in RIPS. The relative energy between the protonand 7Be was obtained from their energies and positionsof hit. The detection efficiency was calculated by aMonte Carlo simulation.

Figure 2 shows the astrophysical S-factor of the7Be(p,,),)8B reaction obtained from the present experiment together with the existing (p,,),) data. 3) The
present data are consistent with the data of Kavanagh,
Vaughn et al. and Filippone et al. within the error. The
extrapolation of the experimental S-factors to zero relative energy was performed with the help of an energy dependence proposed by Tombrello. 4) The result
is slightly lower than the adopted value 22.4 ± 2.1 eVb of Bahcall et al. 5 ) and 21 ± 3 eV b of Thrck-Chieze
et a1. 6 )The present data are limited in the energy range
from 0.6 to 1.7 MeV. A measurement at lower relative
energies with higher precision is under consideration.
120 , - --

100

80

_~~_
H
v

_ _ __tf

x Kavanagh(l960)
oParker(l968)
o Vaughn et al.(1970)
o Wiezorek(1977)(:, . Filippone et al.(1983)• present
Tombrello(1965)- - _. Baker and Spear( 1986)~7.0--~~--~1.0~--~1.5--~2.01m"'-'<-_- , - - - - - - r - - -- . - - -- - - ,Ec.m.(MeV)
PMT"-'r---

Fig_ 2. The astrophysical S-factor for the 7Be{p,,)8B as
a function of relative energy_

Referencesbeam
aluminumpialc

Fig. 1. Schematic view of the experimental setup.

*! A. W. Wright Nucl. Struct. Lab., Phys . Dept., Yale Univ.
*2 Inst. Phys. Nucl. and Centre de Recherches du Cyclotron,
Univ. Catholique de Louvain*3 W. E. Kellogg Lab., California Inst. of Technol.
*4 Nucl. Phys . Lab. GL-IO, Univ. of Washington

1) R . Davis Jr. et al.: Proc_ of the 21st Int. Cosmic Ray
Conf., p. 143 (1990).
2) K. S. Hirata et al.: Phys. Rev., D44, 2241 (1991).
3) B. W. Filippone: Ann. Rev. Nucl. Part. Sci., 36, 717(1986).
4) T. A. Tombrello: Nucl. Phys., 71, 459 (1965).
5) J. N . Bahcall and R. K. Ulrich: Rev. Mod. Phys., 60,
297 (1988); J. N. Bahcall and M. H. Pinsonneault : ibid.,64, 885 (1992).
6) S. Thrck-Chieze, S. Cahen, M. Casse, and C. Doom:Astrophys. J., 335, 415 (1988).

43

RIKEN Accel. Prog. Rep. 27 (1993)

Interaction Cross Sections and Radii of Mass Number
A = 17 Isobars (17N, 17F, and 17Ne)
A. Ozawa, T. Kobayashi, H. Sato, D. Hirata, 1. Tanihata, O. Yamakawa,*l K. Ornata, K. Sugimoto,*2
N. Takahashi, T. Shimoda, D. Olson,*3 W. Christie,*3 and H. Wieman*3
NUCLEAR REACTIONS Be,C,Ale 7N,17N)X, Be,C,Ale 7F, 17 F)X, Be,C,Ale 7Ne, 17 Ne)X,E/ A = 700 MeV; measured interaction cross sections (T1, deduced root mean square raii.
Comparisons of radii between isobars have become
possible with the use of radioactive nuclear beams.
At relativistic and intermediate energies the isospin
dependence of matter radii has been measured forlight nuclei (A < 20) and strong isospin dependence
has been shown. 1,2) With the exception of nuclei thathave neutron halos, the observed global tendency waswell reproduced by a Hartree-Fock (HF) model witha strong density-dependent interaction (Skyrme-III).1)
Isobars of mass number A = 17 provide a very wide
span of T z = (N - Z)/2 with 6 isobars. They include
proton-halo candidates 17Ne (S2p ; separation-energy= 0.96 MeV) and 17F (Sp = 0.60 MeV), and a neutron
halo candidates 17C (Sn = 0.73 MeV) and 17B (S2n =1.21 MeV). Thus, these radii are interesting not only
to see the isospin dependence in general, but also tosearch for halo nuclei.
The 17Ne, 17F, and 17N secondary beams of about
700 A MeV were produced by projectile fragmentation of primary beam accelerated by the Bevalac at theLawrence Berkeley Laboratory. The interaction crosssection ((TI) was measured by means of a transmission
experiment with Be, C, and Al targets. Effective root
mean square radii (RMS) are deduced from the (TI'S by
a Glauber model calculation. 1)
The strong isospin dependence of RMS is seen in
A = 17 isobars, as shown in Fig. 1. Steep increasesof RMS at the proton-rich and neutron-rich sides areobserved. To understand the reason for this increase,
we performed the theoretical calculations for A = 17
isobars by using two microscopical models of the nucleus; the nonrelativistic HF model with a Skyrme-III
potential 3) and the relativistic mean field model. 4) The
results by these models reproduce the rough tendency
of isospin dependence. However, at the proton-rich nu-*1 Fukui Univ.
*2 Osaka Univ.
*3 LBL, Berkeley, U.S.A.

44

1

cleus 17Ne and the neutron-rich nucleus 17B, the observed increases of radii are much stronger than thepredicted ones. This anomalous enhancement of theradius in the same isobars suggests the existence of the
proton halo in 17Ne and the neutron halo in 17B. However, our results show that RMS of 17F is not larger
than the systematics in A = 17 isobars. Thus, fromthe view point of matter size, no evidence is observed
for a proton-halo in 17F.
3.

g 3.

.... " "

E",

E 2.

!

Ct:;

2.
-3/2 -1/2 1/2 3/2

5/2 7/2

Tz

Fig.
1. The isospin dependence for RMS of mass
number A = 17 isobars. The presently determined
experimental values are shown by the closed circles.
Dashed line shows RMS predicted by the nonrelativistic Hartree-Fock calculations with Skyrme-III potential.
Predictions of the relativistic Mean Field calculations
are shown by the solid line.

References
1) I. Tanihata et al.: Phys. Lett., B206, 592 (1988).
2) A. C. C. Villari et al.: ibid., B268, 345 (1991).
3) H. Sato and Y. Okuhara: Phys. Rev., C34, 2171 (1986).
4) D. Hirata et al.: ibid., C44, 1467 (1991).

RIKEN Accel. Prog. Rep. 27 (1993)

Beta-delayed Neutron Decay of 19C and
Its Astrophysical Implications
A. Ozawa, R. N. Boyd, J. Kolata, F. Chloupek, G. Raimann, K. Yoshida, M. Fujimaki,
T. Kobayashi, Y. Watanabe, 1. Tanihata, S. Kubono, and K. Kimura[RADIOACTIVITY 19C({3+ n); measured ,B-delayed En.]In a recent study of inhomogeneous primordial nucleosynthesis models it was found that several critical points exist in the network of nuclides involved. 1)
Specially, masses 15 and 18 are critical to synthesis of
nuclides heavier than mass 20, as synthesis of either
15N or 18 0 will result in a cycling process which will
preclude synthesis of heavier nuclides. 15N is made bybeta-decay of 15C, so the strength of the I5C(n, ')') reaction is crucial for regulating the synthesis of heavier
nuclides. Similarly, 18N is most likely to beta-decayto 18 0, from which it recycles back to 15N, but the
18N(n, ')') reaction could result in breakout from thislower mass cycle, creating heavier nuclides. Thus thelatter reaction is also important in synthesis of heavy
nuclides in the inhomogeneous models. Although some
is known about the level structure in 16C; this has allowed an estimate (actually a lower limit) to be madefor the cross section, virtually nothing is known aboutlevels above the n + I8N threshold in 19N. Thus, it isimportant to study such levels prior to attempting tomeasure cross section of the 18N(n, ')') reaction. Thiscan be done by measuring the energy of delayed neutron emission from the stopped 19C nuclei, as shownin Fig. 1. We have measured the neutron energy by
the time-of-flight (TOF) in the present experiment.
A 19C beam of about 90 A MeV was produced by
the projectile fragmentation of a primary beam 22Ne
accelerated by Ring Cyclotron and separated by the
RIPS facility. The beam was stopped in a thin plastic
scintillator (f"V 10 mm) at the center of an array of neutron detectors. A beta ray emitted from stopped 19C,
which was a start signal for neutron TOF, was detectedby triplet scintillators located up- and down-stream tothe stopper. A delayed neutron emitted from levels
above the n + 18N threshold in 19N was detected by
the array of the neutron detectors that consist of threeplastic walls (100 x 100 x 6 cm 3 ). The energy threshold

15.5 MeV----- 5.32 MeV
18N+n

-OMeV
1~

Fig. 1. Decay scheme of 19C.2)

for neutron in each neutron counters was set to be verylow (around 200 keV). Neutron flight path was about
125 cm. For the calibration of neutron counters, beta
delayed neutron emitted from 17N was detected. Peakfor 380 ke V neutron was clearly shown on its TOF
spectrum.
In order to assign levels above the n + 18N thresholdin 19N, energies of gamma rays emitted from excitedlevels in 18N and beta rays emitted from 19C were alsomeasured by two N aI scintillators (3" </» and a large(10 x 10 x 10 cm 3 ) plastic scintillator, respectively.
Analysis is now in progress.
References
1) F. K. Thielemann et al.: Astrophys. J., (1994) to be
published.
2) F. Ajzenberg-Selove: Nucl. Phys., A475, 1 (1987).

45

RIKEN Accel. Prog. Rep. 21 (1993)

The Decay of 14Be
T. Kishida, T. Nakamura, G. Liu, Y. Watanabe, A. Yoshida, N. Aoi, M. Hirai, M. Ishihara,
H. Okuno, H. Sakurai, T. Teranishi, H. Miyatake, T. Shirakura, E. Ideguchi,
S. Shimoura, S. S. Yamamoto, M. D. Belbot, J. J. Kolata, and M. Zahar
RADIOACTIVITY 9Li(,B-); measured ,B-delayed neutron, triton, a and 'Y spectra;[ deduced logft. 14B deduced level.
In this report, we present the experimental arrangement and preliminary result of the recent experimenton the beta decay of 14Be, which was performed using
RIKEN Ring Cyclotron. The decay of 14Be would be
one of the promising processes in order to observe thesuper-allowed Gamow Teller (GT) beta-decay.1)
The super-allowed GT beta decays occur as beta
decays to the GT giant resonance state. In our case,
Sagawa estimated that the GT giant resonance stateof 14 B would appear around 3 Me V lower than the
ground state of 14Be,2) which means that this excitedstate would be 13 MeV higher than the ground stateof 14B. This GT giant resonance state is unstable forparticle decay; the kinematically possible final statesare 13B + n, 12B + 2n, 11 B + 3n, 11 Be + t, lOBe +t + nand 9Li + a + n. We are, therefore, able todetermine the energy level of the state by measuring
the Q-value of the particle-decay modes listed above.
Figure 1 shows the arrangement of this experiment.
Secondary beams of 14Be were produced at the radioactive beam line RIPS from the fragmentation of
100 MeV lu 18 0 primary beam by a Be target. These
14Be's were transported to the experimental area andstopped in five-layers Si detectors which were placed

1

at the final focus of the RIPS. The implanted 14Be's
decay with a life-time of 4.35 ms. The,B rays fromthe decays were detected with scintillation counters.
The beta-delayed charged particles were stopped in thesame layer of Si where the mother 14Be stopped. The
kinetic energy of these charged particles were measured
by the Si detectors. The beta-delayed neutrons weredetected by three neutron counter walls which wereplaced 2 m apart from the final focus. The kinetic energy of neutrons was measured with the TOF method.
Ge and NaI detectors were used to detect the betadelayed 'Y emission.
The analysis of the data is now in progress. Figure 2 shows the TOF spectrum of a neutron counter.
This spectrum contains information on the 14 B excitedstates via the reaction 14B* ~13B + n.
18()

160

/40

120
r/)

~
~

) 0(}

'0

1
'"

13 MeV

1 MeV

0.3 MeV

80
6()

40

20

Charged Particle Veto

\ '" L

r-::=:-Jl'B~--1-----t+---t-1L=-::J
I-----t---l~~1 ~_

86
\

/

Qll Q12(RIPS)

Storr

J
,,___

o.g,~,I

Veto Sc,nt

Fig. 2. TOF spectrum of a neutron counter. The values in the figure are the corresponding neutron kinetic
energies.

:~ \,E£:;;B V/ -----~eutron~Counters

Fig. 1. Schematic diagram of the experimental arrangement.

46

Toe channel number [ch.]References
1) H. Sagawa, 1. Hamamoto, and M. Ishihara: Phys. Lett.,
B303, 215 (1993).
2) Private communication.

RIKEN Accel. Prog. Rep. 27 (1993)

Coulomb Dissociation of 11 Be
T. Nakamura, S. Shimoura, T. Kobayashi, T. Teranishi, N. Aoi, Y. Doki, M. Fujimaki, N. Inabe, N. Iwasa,
K. Katori, T. Kubo, T. Suzuki, 1. Tanihata, Y. Watanabe, A. Yoshida, and M. Ishihara
NUCLEAR REACTION 11 Be + Pb, E(l1 Be) = 72 MeV /nucleon,Coulomb dissociation,neutron halo; deduced dipole strength function dB (El)/dE x .

One of the anomalous properties in halo nuclei is the
low-lying dipole strength in the Coulomb dissociation.
Earlier works on 11 Li l - 3 ) have shown that a peak appears at the excitation energy of about 1 MeV in the
Coulomb dissociation energy spectrum. So far, however, the mechanism to yield such dipole strength has
not been fully understood. One plausible mechanism isthe excitation of a new collective mode, so called, thesoft dipole resonance. The other is the direct breakup
to continuum states. Here, we report results from a
11 Be + Pb reaction at 72 MeV/nucleon to disentangle the two possible mechanisms. The 11 Be nucleus
was chosen for the sake of simplicity. Because 11 Be
consists of a lOBe core plus a single halo neutron, theexcitation spectrum may be free from complication due
to the two-neutron correlation expected in nuclei suchas 11 Li.
The experiment was performed at the radioactive
beam line RIPS at RIKEN Ring Cyclotron. The secondary 11 Be beam was produced and separated by the
RIPS and was incident upon a Pb target. Two outgoing particles (n + lOBe) from the dissociation process
were measured in coincidence by using a system composed of a dipole magnet , a drift chamber, chargedparticle hodoscopes and neutron counter walls. The
excitation energy Ex was determined event-by-eventby reconstructing the invariant mass of the excited
11 Be from the momentum vectors of detected particles.
Figure 1 shows the obtained excitation energy spectrum of Coulomb dissociation of 11 Be after efficiency
correction and subtraction of the contribution from nuclear dissociation. The characteristic feature of thespectrum is a prominent peak which appears at Ex =800 keY. The dipole strength function dB (El)/dE x
was then deduced using the virtual photon theory,4)
as shown in Fig. 2. The deduced dipole strength function was analyzed in terms of the direct breakup of ahalo nucleus, in which the dipole strength function for
11 Be is expressed in a simple analytical form as,5)dB(El)/dEx =Ns x Const. x E;/2(Ex - Es)3/2 / E~,
where N s represents the spectroscopic factor for the2S 1 / 2 state and Es represents the separation energy.
We fitted the data with this function, taking N sandEs as free parameters. The effect of Coulomb post acceleration and the detector resolutions were evaluated

1

200

~

~

1..11

.0

1.0

J

o.a

S

~

)

0.0

,1111
IJ

ttt

Ij I 1 ~

~

-0..&

t

•

Erel [MeV]
!

I

2

3

Ell [MeV]

Fig. 1. The energy spectrum of Coulomb dissociation ofllBe. Ex = Erel + Es.

I

E rel [MeV]Ell [MeV]

Fig. 2. Deduced B(E1) strength spectrum; open diamonds represent the B(E1) strength deduced from thedata in Fig. 1. The solid line shows the dipole strength
function analyzed based on the direct breakup picture(Es = 540 ± 40 keY).

by Monte Carlo simulations and were incorporat~d inthe fitting procedure. The solid curve corresponds tothe Es = 540±40 keY, where the best fit was obtained.
The resultant value for Es is in good agreement withthe known separation energy of 504 ± 6 ke V, whichindicates that the direct breakup picture describes the
Coulomb dissociation of 11 Be well.
References
1) S. Shimoura: Talk given at NFFS Conf. BernkasselKues, Germany (1992).
2) K. Ieki et al.: Phys. Rev. Lett., 70, 6 (1993).
3) D. Sackett et al.: Phys. Rev., C48, 118 (1993).
4) C.A. Bertulani and G. Baur: Phys. Rep., 163, 299(1988).
5) G. Baur et al.: Nucl. Phys., A550, 527 (1992).
47

RIKEN Accel. Prog. Rep. 27 (1993)

Mass Dependence of Pion Production in Heavy Ion Collisions
Near but Below Threshold t
J. Miller,*1 G. F. Krebs,*1 J. Panetta,*1 L. s. Schroeder,*1 P. N. Kirk,*2 z. -F. Wang,*2
W. Bauer,*3 W. Benenson,*3 D. Cebra,*3 M. Cronqvist,*3 B. -A. Li, R. Pfaff,*3
T. Reposeur,*3 J. Stevenson,*3 A. V. Molen,*3 G. Westfall,*3 J. S. Winfield,*3
B. Young,*3 T. Murakami,*4 T. Suzuki, and I. Tanihata[Nuclear reaction, subthreshold pion production, mass dependence.]
We have measured the inclusive cross section for production of negative pions near mid-rapidity in 20Ne +NaF, 139La + 13 9La, and 197 Au + 197 Au collisions at
E = 183 and 236A MeV. The reaction Au + Au is theheaviest system from which the subthreshold pion production has been measured to date. Primary beams
were accelerated by the Bevalac at Lawrence Berkeley Laboratory and negative pions were detracted bya magnetic spectrometer.
Figure 1 shows the obtained inclusive cross sectionsof the negative pions. It shows an exponential dependence on pion energy that is typical of the pion production both above and below threshold. Also the othercharacter shows no drastic change below and above thethreshold.
The present data with other data at different energies give the almost constant yield ratio,

105,--,104
'"u
.&J

E

• ~ Q

~gi

>103
~

"

6

102 [

bl'"

~ %100

6

*1
*2
*3
*4
48

Extracted from Phys. Lett., B314, 7 (1993).
LBL, Univ. of California
Louisiana State Univ.
NSCL, Michigan State Univ.
Tokyo Institute of Technology

8ern =8So

~o

,!,O?
6
6

6

~~

6
6

Au+Au

0

6
6

• La+La
6

6

Ne+NaF

0

6

100

6

I
6

200

Tern (MeV)l~rE-----------------------=-(b)r-;:;:104~

EIA=183 MeVuE --~ 103~~102

8ern =80°
6

6
6

6
6

We compared these data with the results of two
calculations based on the nuclear Boltzmann-UehlingUhlenbeck (BUU) equation. One is the perturbative
calculation and the other is the non-perturbative calculation. We see that the perturbative BUU calculation
gives better fit to the energy dependence of the ratio.
In conclusion, at these energies the pion production
process is still dominated by nucleon-nucleon collisions.

EIA=236 MeV

6

;102

~

S

dcy
/ dcy
do' (La + La) do' (Ne + NaF) = 20.

(a)

Co

o

ff

6

o Au+Au• La+La
6 Ne+NaF

6
6

6
6

~

I

I

100

200

C. Ii'

Tern (MeV)

Fig. 1. Inclusive cross section versus pion kinetic energy
in the center of mass for reactions at E = 236 A MeV(a) and at E = 183 A MeV (b).

RIKEN Accel. Prog. Rep. 27 (1993)

Are All Dripline Nuclei Spherical?
1. Tanihata[Nuclear structure, Dripline nuclei.]
Recent development in high-intensity heavy ions at
medium and high energies provided us explosive discoveries of new isotopes. As a result we now believethat the neutron drip line has been reached up to Z
= 9 and the proton drip line ' has been reached up to 'Z = 18. 1 ) A pronounced systematics is seen in these
driplines.
Let us consider adding two neutrons to a nucleus
near the neutron drip line. When the two neutrons
are added to a new orbital, it may form a bound or an
unbound nucleus depending on the energy of the lastorbitals. St'ppose that the nucleus is bound and thelast orbital has a degeneracy of more than two. Thenthe nucleus with two more neutrons is again boundbecause more binding energy is available. It is due tothe increased number of two nucleon interaction chains
and is seen in a relativistic mean field calculation. 2)This situation continues until this orbital is completely
filled. The nucleus may become unbound only when
two neutrons are added to a new orbital. The same istrue for adding two protons to a nucleus near the proton drip line. The Coulomb repulsion may introduce aslight change but it is not seen in the following examination. Therefore the drip line indicates that the lastorbital is completely filled there.
In the spherical shell model, an orbital has degeneracy of 2j + 1. On the other hand the degeneracy isremoved except for the nuclear spin in the deformed
Nilsson orbitals and all of them have degeneracy of 2.
As seen in Fig. 1, all dripline nuclei are consistent withthe closure of spherical shell model orbitals in the order, except for the well known lowering of 2S 1 / 2 for Be
isotopes and probably the same effect for 1 7 Ne for the
proton orbital.
It is found that the known drip lines can be understood as the closure of the spherical orbitals. It sug-

Fig. 1. A chart for light nuclei. Corresponding sphericalshell model orbitals are shown by the thick lines. All
dripline nuclei are consistent with the closure of thespherical orbitals.

gests that all known drip line nuclei are spherical. It
would be interesting to see how it can be understoodby a microscopic model of nuclei. This fact also gives
the first visual effect of sub-shells to gross propertiesof nuclei. The changes of the order of shell orbitals areseen in the neutron drip line and possibly in the proton
drip line. It is considered to be due to the character ofa loosely bound orbital.

References
1) A. C. Mueller and B. M. Sherrill: Ann. Rev. of Nucl.
and Part. Sci., 43, in press.
2) D. Hirata, H. Toki, T. Watabe, 1. Tanihata, and B. V.
Carlson: Phys. Rev., C44, 1467 (1991).

49

RIKEN Accel. Prog. Rep. 27 (1993)

Experimental Study of the 8He + p Elastic and Inelastic Scattering
A. A. Korsheninnikov, K. Yoshida, D. V. Aleksandrov, N. Aoi, Y. Doki, M. F\ljimaki, N. Inabe,
T. Kobayashi, H. Kumagai, C.-B. Moon, E. Yu. Nikolskii, M. M. Obuti, A. A. Ogloblin,
A. Ozawa, S. Shimoura, T. Suzuki, 1. Tanihata, Y. Watanabe, and M. Yanokura
NUCLEAR REACTIONS , radioactive nuclar beam, p(8He,p), p(8He, p4,6,8He) , p(8He,pn 4,6He),[ p(8He,p2n 4,6He), p(8He,2n4,6He), p(8He,n 4,6He), E/ A = 72 MeV.

The 8He nucleus has the largest neutron to proton
ratio among known bound nuclei and contains four valence neutrons, while neutron halo in 11 Li has two valence neutrons as well as in 6He. To study structureof 8He one needs data on the elastic scattering andexcited states.
We studied the 8He+p collisions using the 8He beam
produced by RIPS. The beam (72 ± 3 A MeV) hitstargets CH 2 and C. Scattering angles and energies ofrecoil protons were determined by an SSD-telescope.
Elastically scattered 8He and 4,6He from the 8He decay were bent in a dipole magnet and measured by adrift chamber. To detect neutrons from the 8He dissociation, we used 5 neutron walls.
Measured inclusive spectrum of protons is shown in
Fig. IA. A peak corresponding to the elastic scattering
is clearly seen in the spectrum. The elastic scattering angular distribution is shown in Fig. 2A. Figure 1
shows also spectra for coincidences p+6He, p+n, andp+6He+n. Figure IE shows the spectrum for coincidences p+ 7He eHe was selected from the invariant
mass spectrum of 6He+n). In all the spectra in Fig.
1B- E, a definite peak is observed at ,,-,3.6 MeV. The
8He excited state is also observed in the inclusive spectrum as shown in the inset in Fig. 1A. The observed
1500

1000

1000

... 100
III

.&l

E

10

~

c:
'0

0

'0

.1

p(8H~.p)8H~

~"\
A

10

p(8H~.p)8Hcj.6, :~~\
~

.01

lB

.01

20 30 40 50 60 70

1

\

"-

20 30 40 50 60 70

eeM ,deg
Fig. 2. Angular distributions for elastic (A) and inelastic(B) scattering 8He+p. The curve in Fig. 2B shows thecoupled channel calculation for J11" = 2+ based on theelastic scattering calculation shown in Fig. 2A.

state 8He* lies above thresholds 6He+2n and 4He+4n.
The obtained parameters of the state are: E;He =3.6 ± 0.2 MeV, f < 1 MeV, f4He+4n/f6He+2n ::; 5%.
The inelastic scattering angular distribution is shownin Fig. 2B. It is consistent with J7r = 2+ for 8He*.
We also applied invariant mass measurements andobserved unstable states in 8He, 7He, 6He, and sHe.
Figure 3 shows a spectrum for coincidences 6He+n+n.
In the spectrum, a definite peak is observed. Obtained parameters of the 8He excited state are E;He =3.55 ± 0.15 MeV , r = 0.5 ± 0.35 MeV. They are ingood agreement with the results obtained by the othermethod shown before and are colse to the results obtained in Ref. 1.
p~He,2n6He)

40
:zoo
160
~

I:l:2D

30

~

20

~

::I

8

:i
iii

;;

10

co

10

0

0 1 2 3 4 5 6
E·Slle, MeV

Fig. 3. Invariant mass spectra from reaction p(8He,
nn 6He). Curves show calculations for final state interactions 6He+n (1) and n+n (2).
2

E· 8Heo MeV

b

10

14

18

E· 8Heo MeV

Fig. 1. Spectra of protons as a function of the 8He excitation energy. Curves show calculations for final stateinteraction n+ 6 He at state 7He.

50

References
1) H. Bohlen et al.: Int. Conf. on Nuclei far from Stability,
Bernkastel, Germany (1992).

RIKEN Accel. Prog. Rep. 27 (1993)

Observation of lOHe
A. A. Korsheninnikov, K. Yoshida, D. V. Aleksandrov, N. Aoi, Y. Doki, M. Fujimaki, N. Inabe,
T. Kobayashi, H. Kumagai, C.-B. Moon, E. Yu. Nikolskii, M. M. Obuti, A. A. Ogloblin,
A. Ozawa, S. Shimoura, T. Suzuki, 1. Tanihata, Y. Watanabe, and M. Yanokura

1

NUCLEAR REACTIONS, radioactive nuclear beam, CD 2 , C(l1 Li, 2n 8,6He) ,[ CD 2 , C(l1 Li, n 8,6He), E/ A = 60 MeV.

We have carried out an experimental search for thesuperheavy helium isotope 10He with taking into account the following two different mechanisms to produce 10He: (1) The 10He resonance can be manifested
as a final state interaction of particles 8He + n + nemitted in projectile fragmentation (e.g., in the 11 Li
fragmentation). (2) One proton transfer reaction suchas 11 Li + d --+10 He + 3He can also produce 10He.
The experiment was carried out using the secondary ·beam of 11 Li produced by RIPS. Invariant mass spectrum was measured for the 8He + n + n and some othertwo and three particles in coincidence. The 11 Li beamwith the energy 61 ± 3 A MeV hits thick targets CD 2
and C (390 mg/cm 2 and 280 mg/cm 2 , respectively).
Neutrons were detected by five layers of neutron walls.
Charged particles were bent in a dipole magnet andthen detected by a drift chamber and a scintillation
counter hodoscope.
The resultant spectra are presented in Fig. 1 as afunction of relative energy in the 8He + n + n system,
Es He - n - n · Figure 1A shows the distribution obtainedwith the CD 2 target. A strong peak is observed at
ES He - n - n rv 1.2 MeV. To see any possible target dependence of the spectrum, we show the corresponding
spectrum for a deuteron target. As shown in Fig. 1B, apeak is seen at the same energy as in Fig. 1A. The corresponding spectrum of the C target also shows slightevidence of a peak at the same energy. Therefore it
is considered that 10He is produced in the projectile
fragmentation of 11 Li nuclei.
We examined shapes of spectra from processes otherthen 10He decay and considered different phase spaces
and final state interactions between different particles.
The results under various assumptions are shown by
curves 1- 5 in Fig. 1. They do not reproduce the observed peak.
Therefore the peak can be explained only as thelOHe resonance. The obtained parameters of the state

ISO
~

'c
=
...>. 100::A

llLl+CD 2

18

llLi+d

~

:E
...
~

..0-

,.

50

~

~

'c

80

...

60

=
>.
~

.&:

:E
...
~

40

-c
~

> 20
~2 -1 0

1

2

3

4

5

6

ESIle-n-n, MeV

Fig. 1. Invariant mass spectra of 8He + n + n from reactions: A , CD 2 (llLi, 2n8He) , B, d(llLi, 2n 8He). Curves
1- 5 show the phase space and final state interaction
calculations under different conditions but without thelOHe resonance.

are: the energy above the 8He + n + n threshold
ESHe - n - n = 1.2±0.3 MeV and the width r ::; 1.2 MeV.
These parameters were found with taking into accountuncertainty of the background subtraction (curves 1- 5
in Fig. 1).
We also studied two particle coincidences 8He + n.
The main part of the 8He + n spectrum is understoodas a decay from the 10He resonance. In the same experiment, we studied coincidences 6He+n+n and 6He+n
and observed the known states 8He* and 7He.

51

RIKEN Accel. Prog. Rep. 27 (1993)

Project at GSI "Determination of Neutron Skin
Thicknesses for Na Isotopes"
T. Suzuki, T. Kobayashi, K. Yoshida, I. Tanihata, G. Miinzenberg,* H. Geissel,*
K. Siimmerer,* F. Nickel,* W. Schwab,* H. Irnich,* K. H. Behr,* and K. Burkard*
NUCLEAR REACTIONS; 40 Ar, 27 Al + Be, E = 1050 MeV jnucleon; Secondary beams;(ANa + C, AI, Pb; A = 20-32); Density distribution; Relativistic Mean Field Theory.

0'1

Recently, thick neutron skins are observed in 6,8He,
but extraction of the skin thickness is somewhat indirect because no information on radii of proton distribution is available. I) However, for N a isotopes rootmean-square radii of the charge distribution were determined by the isotope shift measurements. 2 ) Therefore the measurement of the interaction cross sections
0' I, from which the matter radii are determined, provides the unique opportunity for direct comparison ofdifference between proton and neutron distributions.
For the measurement of the 0'1, we use the transmission method. For this method we identify and countthe number of incident nuclei (Nin) before the reaction
target and then count the number of the same nuclei(Nout ), the nuclei without reaction, after the target .

The 0'1 can then be expressed as:
0'1

1
(Nin
= -In
-) .

Nt

N out

The measurement of 0'1 requires a separator of radioactive nuclei and a spectrometer after a reaction
target. Although the FRS is designed for productionof secondary radioactive beams, a large enough space
is not yet available to put another spectrometer behindit. However, our study of its optics showed that a function of the FRS can be separated into two parts andwe can use the FRS as the separator and the spectrometer simultaneously. Figure 1 shows this arrangementof the FRS.

F4

FI: dispersive
F2: dispersive
F3: dispersive
F4: achromatic

reactiontargetFig. 1. The FRS separator and spectrometer at GSI for the interaction cross section measurement.

Radioactive nuclei produced via the projectile fragmentation are separated according to their AjZ at Fl,then guided to the reaction target located at F2. Individual nucleus is identified by its TOF (between Fl
and F2) and dEjdx. After the reaction target, noninteracted nuclei are guided through F3 to F4. These
nuclei are identified again by their TOF (between F2and F4) and dEjdx. The momentum and angularspreads of the incident beam to the reaction target
can be adjusted so that all the non-interacted nuclei
can reach F4. The momentum spread is restricted at
Fl and F2 by selecting the beam position. The angular spread is selected by the incident angle of a nucleus
into the reaction target. We can determine the aI with*52

GSI, Darmstadt, Germany

accuracy better than 1% unless counting statistics islimited due to the weak intensity of secondary beams.
Once this method is established, one can easily measure the a I of any secondary nuclei. Also the momentum distribution of the fragments from radioactive
beams can be measured under the same geometry butchanging the setting of magnets after F2.
The experimental system is now under construction.
The first experiment is scheduled in coming spring.
References
1) 1. Tanihata et al.: Phys. Lett., B289, 261 (1992).
2) G. Huber et al.: Phys. Rev., C18, 2342 (1978).

2. Atomic and Solid-State Physics

RIKEN Accel. Prog. Rep. 27 (1993)

Charge Asymmetry of Ionization Cross Sections of Atomic
Hydrogen by Antiproton and Proton Impact
N. Toshima
The difference of the ionization cross sections ofatomic hydrogen by antiproton and proton impact
arises solely from higher-order perturbations since thefirst-order Born cross section does not depend on thesign of the projectile. Study of charge asymmetry of
the ionization cross sections gives direct information of
the effect of higher-order interactions. Ermolaev 1 ) calculated the ionization cross section of atomic hydrogenby antiproton impact by means of the coupled-channel
method and compared the result with the ionization
cross section by proton impact. The cross section ratio of the quantal calculation was different from theresult of the CTMC (classical trajectory Monte Carlo)
calculation. 2) The quantal ratio shows weaker energydependence than the classical one in the velocity range
1 < v < 5 a. u., while the quantal ratio shows a broad
maximum exceeding about 7% in the range 5 < v < 11a.u., where the classical ratio is almost constant andalways smaller than unity. The structure of the quantal result in the higher-energy region was attributed to
the Barkas effect which is by some reason missing in
the classical description.
In this report we present the results of calculations by the coupled-channel method employing a large
number of continuum states both on the target andon the projectile. 3 ) The eigenfunctions of each centerare expanded further in terms of G TO basis functions
generating the nonlinear parameters of the GTO as amodified geometrical progression. The expansion coefficients are determined so as to diagonalize the atomic
Hamiltonian of the target and the projectile. 4 ) The
GTO expansion method has the advantage that all thematrix elements can be evaluated analytically in contrast with the standard procedure based on the Slatertype orbital expansion, in which numerical integration
is inevitable for two-center matrix elements.
The cross section ratios are plotted in Fig. 1. The
present cross section ratio is closer to the classicalvalue 2 ) than the result of Ermolaev.1) The difference
between the two quantal results arises mainly from thecontribution of the projectile continuum states. The
partial cross sections for the ionization into the target continuum states do not depend on the sign of the
projectile charge strongly whereas the partial cross sections for the projectile continuum states do strikingly
below 200 keY. We do not see a distinct Barkas effectaround 1500 keY at variance with Ermolaev's result.
1.4 ,--....,...----r-...,--,.--,--....,...---,--...,--,.-----,

1.3

1.2

C. 1.1-:§' I .0 I-----+-,---_ _ _-+-_~=------"~--O----;~0 . 9t5' 0 .8
0 .7

0 .6
0.5 L----L------1._..L---L..._L----'-------1._...I....--L...---'o10

velocity(a.u.)

Fig. 1. The ratio of the ionization cross sections of atomic
hydrogen by antiproton and proton impact. Open circles are present coupled-channel calculations and solid
circles are from Ermolaev. 1 ) Solid line is the CTMC
results of Schultz. 2 )The projectile continuum states are required even for
the antiproton which interacts with the electron repulsively. They are necessary to make more complete thedescription of the electron-cloud distribution repelledby the antiproton. In this sense the ionization into theantiproton continuum is essentially different from theso-called capture to the continuum (CTC) componentof positive ions.
References
1) A. M. Ermolaev: Phys. Lett., A149, 151 (1990).
2) D. R. Schultz: Phys. Rev., A40, 2330 (1989).
3) N. Toshima: Phys. Lett., A175, 133 (1993).
4) N. Toshima and J. Eichler: Phys. Rev. Lett., 66, 1050
(1991); Phys. Rev., A46, 2564 (1992); N. Toshima: J.
Phys., B25, L635 (1992).

53

RIKEN Accel. Prog. Rep. 27 (1993)

Double Excitation of H- by Fast Proton and Anti-Proton Impact
II. Spectral Line-profile of an Ejected Electronfrom 2 s2p 1 po Shape Resonance
K. Hino, M. Nagase,* H. Okamoto,** T. Morishita,** M. Matsuzawa, and M. Kimura
In a previous report,1) we calculated the cross sections for the double electron excitation of H- by the
proton and anti-proton impact using the 67 state closecoupling (CC) calculation in comparison with experimental data. 2- 4 ) Here we report the improved theoretical results within the same theoretical frame work.

6

> 4

~
E
(.)
<0

b,...
W
~

2
o

o

0

"0

To calculate the double electron excitation cross sections of H- by the p and p impacts, we employ an improved basis set, i. e., the 97 state one to expand thetotal wave function.
The set consists of the discrete ls2 1 se, 2s2 1 se and2p2 1 De states, the 2s2p 1 po shape resonance state andthe lskp 1 po continuum. These continua are properly
discretized and incorporated into the CC calculation.
Figure 1 shows the calculated line-profile of an ejected
electron from the 2s2p 1 po shape resonance state by
the p impact at 1.5 MeV lu in comparison with thedata of the photodetachment of H- observed by Halkaet al. 5 ) for the decay into an H(N = 2) channel. (theexperimental data are normalized to our theoreticalresults at the peak position.) The calculated results by
the p impact are similar to those by the p impact. It isfound that our calculated profile is in good agreementwith the photodetachment data.

o~1~O~.9~6~-1~O~.9=8~--711~.O=O~~1~1~.02

E(eV)Fig. 1. Spectral line profile dO" / dE of an electron ejectedfrom the 2s2p 1 po state by proton impact at the incident energy of 1. 5 MeV. open circle : experimental line
profile obtained by Halka et al. 5) The excitation energy
E is gauged from the ground state of H- and calculated
based on the Rydberg constant for the hydrogen atom
RH = 13.59827 eV.

*Berg Electronics** Department of Applied Physics and Chemistry, University
of Electro-Communications

54

References
1) K. Hino et al.: RIKEN Accel. Prog. Rep., 26 , 79 (1992).
2) P. W. Arcuni and D. Schneider: Phys. Rev., A36 , 3059
(1987).

3) J. O. Pedersen and P. Hvelplund: Phys. Rev. Lett, 62,
2373 (1989).
4) J. P. Giese et al.: Phys. Rev. , A42, 1231 (1990).
5) M. Halka et al.: ibid., A46, 6942 (1992).

RIKEN Accel. Prog. Rep. 27 (1993)

Photodetachment Spectra of HJ. Tang, Y. Wakabayashi,* M. Matsuzawa, S. Watanabe, and 1. Shimamura

Accurate ab initio calculations of the cross sections
for photodetachment of H- are few,!) especially at
photon energies near and above the threshold of the
production of an H atom in an n=3 state. Discrepancy is found among these calculations, even for thebroad shape resonance just above the n = 2 threshold.
Only recently, the eigenchannel R- matrix method has
been applied in a broader energy region ranging up to
the n = 4 threshold. 1) We have recently proposed an
accurate and powerful computational method, the hyperspherical close-coupling (HSCC) method, for twoelectron atoms. 2 ) This method takes advantage of thehyperspherical coordinates, i.e. , a pair of collective
variables R and a, which replace the independentelectron radial coordinates rl and r2. The hyperradius ·+ r~ measures the 'size' of the electron pairR=
and the hyperangle a = arctan(r2/rI) describes thedegree of radial electron-electron correlation. The accuracy and efficiency of the method have been demonstrated on various physical quantities of He.3 )We apply the close-coupling method in terms of
the hyperspherical coordinates to the two-electron system H-. A two-dimensional matching procedure isused to connect the close-coupling wave function to anindependent-electron wave function in the asymptotic
region. The latter is described as the wave function ofa detached electron moving in a dipole potential fieldof a neutral hydrogen atom. The total photodetachment cross sections and the partial cross sections forthe production of H atoms in different states n arecalculated up to the n = 4 hydrogenic threshold.
The quality of the wave function for the initial stateof photodetachment of H- , i.e., the ground 1 S state, is
expected to be a decisive factor for the accuracy of thedipole matrix element. This is partly because the overlap integral between the initial and final states is small,and partly because the ground state of H- is weakly
bound. Using initial-state wave functions of varying
degrees of accuracy, we found that the magnitude andshape of the 1 po shape resonance just above the n = 2
threshold depend sensitively on the initial-state wave
function. This appears to be one of the reasons for the
disparity among the cross sections in the literature.
Our calculated partial cross sections below the n = 4
threshold are substantially different from the results ofeigenchannel R-matrix calculations. 1) In the R-matrix
results, the partial cross section for the production ofH(n = 2) atoms is larger than that for the productionof H( n = 1) atoms at energies below the n = 4 threshold. This is difficult to understand in the nonresonant

Jrr*photodetachment, which is induced by a one-electron
dipole operator. The H( n = 1) production is a oneelectron excitation process, while the H(n = 2) production is a two-electron excitation process with one
electron detached and the other excited; the latter process occurs only through the electron-electron correlation or configuration mixing. Our calculated results,
as we expect , show that the H(n = 1) partial crosssection dominates over the H(n = 2) partial cross section in the energy regions of nonresonant photodetachment, while the latter may be larger in some regionsof resonances. In Fig. 1, the calculated total cross sections are compared with experimental spectra. 4 ,5) We
see that the present results are in excellent agreementwith experiments. Details of this work will be published elsewhere. 6 )

60
~

~40
c
o
~ 20

~

00

(f)

CJ)
CJ)

o

o
+-'

C

Q)

E

~
()

co

Q)
"0

o

(5
J::

0..

12.6

12.7
Photo Energy (eV)12.8

Fig. 1. Comparison of the calculated total photodetachment cross sections (solid lines) with experiments (circles) (a) near the n = 2 threshold and (b) below then = 3 threshold.

References
1) H. R. Sadeghpour, C. H. Greene, and M. Cavagnero:
Phys. Rev. , A45 , 1587 (1992).
2) J.-Z. Tang, S. Watanabe, and M. Matsuzawa: ibid.,
A46, 2437 (1992).
3) J.-Z. Tang, S. Watanabe, and M. Matsuzawa: ibid., p.
3758 ; ibid., A48 , 841 (1993).
4) M. Halka et al.: ibid., A46, 6942 (1992).
5) M. Halka et al.: ibid., A44, 6127 (1991); M. Halka:
Private communication.
6) J.-Z. Tang et al.: Accepted for publication in Phys. Rev.
A.

Dept. Appl. Phys. Chern., Univ. Electro-Cornrnun.

55

RIKEN Accel. Prog. Rep. 27 (1993)

Double Ionization of Helium by Compton Scattering
K. Hino, P. M. Bergstrom, Jr., * and J. H. Macek*
Thnable, high intensity radiation from synchrotron
sources has recently been applied to experiments measuring the ratio of double to single ionization of helium by photon impact, against which the current theoretical understanding of electron-electron interactions
may be examined. 1) While the agreement between theory and experiment has been quite reasonable for photon energies from near threshold to 12 ke V, Samson,
Greene and Bartlett 2) have recently noted the importance of the Compton scattering process to the interpretation of these measurements. Indeed, most experiments have relied on measuring time of flight ofresidual ions, and have not yet been sensitive enoughto discriminate ions produced by photoionization fromthose produced by Compton scattering. Here the ratio of double to single ionization for helium by photon
impact reads

R= a cs+ + a ph+
2

2

(1)

+
+,
a cs + a ph

at

where
and a~: are the single and double ionization
cross sections by Compton scattering, and h and a~t
are counterparts by photoionization. The inability to
distinguish between the two processes becomes problematic at high photon energies, where Compton scattering cross sections become comparable to photoionization cross sections at several ke V and are dominantnear 10 keY. Although the two distinct processes contribute to the overall ratio R of Eq. 1, experimental
measurements for R above 6 keY take similar values
to the theoretical asymptotic value of photoionization.
Here, we report the ab initio calculations of the double ionization of helium due to Compton scattering
using the lowest-order many-body perturbation theory and the A 2-approximation to the photon-electroninteraction. 3) There exist substantial differences between Compton scattering and photoionization. (1)The most probable ejected energy of electrons, equivalent to the energy transfer of photons to an atom,
by Compton scattering is significantly small relative
to that of photoionized electrons. 2) (2) In photoionization, the non-relativistic dipole approximation to thephoton-electron interaction is known to hold correctly
to relatively high photon energy region due to a cancel-

*
56

a:

Dept. of Phys. and Astronomy, Univ. of Tennessee, and Oak
Ridge Nat'l. Lab.

lation effect of relativistic and retardation effects. In
contrast with that, the momentum transfer of photons
to an atom is relatively large in Compton scatteringand the dipole approximation is not valid.
We refer here to the contribution of Compton scattering to the ratio R of double to single ionization inhelium at energies where this process is important. According to our calculations, Compton scattering dominates photoionization above 6 keV,3) reflecting the importance of this process to the total ionization crosssection at these energies. In Table 1 we tabulate our results for the overall ratio R as well as the individual ratios due to Compton scattering and photoionization atenergies from 4 ke V to 12 ke V. Our overall ratio has ashallow dip structure around 6 keY, which corresponds
to a transitional change of the dominant ionizing process from photoionization to Compton scattering. Furthermore, the Compton scattering ratio appears to beapproaching to an asymptotic value of 1.66% at highenergy, which is almost the same as the asymptote predicted for photoionization, despite the intrinsic differences between the two processes described above.
Table 1. Ratios (%) of double to single ionization cross sections of helium vs the incident photon energy W (ke V).
R is the ratio defined in Eq. 1. Res and Rph represent
ratios due to Compton scattering and photoionization,
2+

u 2+

U cs

U ph

that is Res = ~ and Rph = 4, respectively.
W

4.0
6.0
8.0
10.0
12.0

R
1.57
1.38
1.54
1.65
1.67

Res
0.44
1.01
1.49
1.65
1.66

Rph
1.73
1.68
1.66
1.64
1.63

References
1) K. Hino et al.: Phys. Rev., A48, 1271 (1993) and references therein.
2) J. A. R. Samson, C. H. Greene, and R. J. Bartlett: Phys.
Rev. Lett., 71, 201 (1993).
3) K. Hino, P. M. Bergstrom, Jr., and J. H. Macek: ibid.,(submitted).

RIKEN Accel. Prog. Rep. 27 (1993)

Energy Shift in the Molecules [(ddJ-t)-d]ee and [(dtJ-t)-d]ee
M. R. Harston, S. Hara, I. Shimaura, and M. Kamimura
Muon-catalyzed d-t fusion occurs within a molecule[(dtJ1)-d]ee , where d is a deuteron, t a triton, J1 a negative muon, and e an electron. Therefore, the rateof the formation of this molecule in collisions of tJ1
with deuterium D2 is crucial for determining the net
rate of muon-catalyzed d-t fusion in D2/T2 mixtures.
Similarly, the rate of the formation of the molecule[(ddJ1)-d]ee in collisions of dJ1 with D2 is crucial for
determining the net rate of muon-catalyzed d-d fusionin D 2. These formation processes are resonance processes, and hence, the rates depend sensitively on theexact energy levels of the muonic molecules.
The sizes of the three-body systems dtJ1 and ddJ1
are much s~aller than their distance from the othernucleus d and the size of the electronic orbitals. Hence,each of the muonic molecules may be approximated asconsisting of two independent subsystems, namely thethree-body system dtJ1 or ddJ1 and a deuterium-likemolecule in which one of the d nuclei is replaced by afictitious nucleus obtained by compressing dtJ1 or ddJ1
into a point charge.
The nonrelativistic energies of the isolated dtJ1 andddJ1 were calculated accurately,l) and were corrected
for relativistic, hyperfine, finite-nuclear-size, vacuumpolarization, and other effects 2,3) as well as for the
perturbation potential between the two subsystems. 2,4)The sum of these corrections agrees with experimental
results for [(ddJ1)-d]ee to within about 0.1 meV. However, this remarkable agreement must be fortuitous,
since one of the corrections, at least, was not calculated to this high accuracy; a nonrelativistic perturbation correction of 1.0 me V was first calculated by useof the same method that led to a result 1.2 meV for[(dtJ1)-d]ee , which was proven later to be in error bya factor of 4.1,4) and then scaled (without theoreticaljustification) by the same factor 4.1 to obtain a value
0.24 meV for [(ddJ1)-d]ee. Unfortunately, no calculations for [(ddJ1)-d]ee of higher accuracy are found in
the literature, and the error in the value 0.24 meV isdifficult to assess. Here we intend to point out an effectthat has been calculated by no other previous authors
and that leads to a correction of the order of me V.
The perturbation potential may be divided into
multipole interactions of dtJ1 or ddJ1 with the other
deuteron and the electrons. The deuteron contribution to the first-order correction due to the monopole
interaction Vo is negligibly small. The first-order electron contribution due to Vo scales in proportion to theelectron density at and around the position of dtJ1 or
ddJ1. In the literature, this contribution is calculated

for a D-like atom model instead of the D2-like subsystem in the unperturbed system, and is then scaled
according to the electron-density ratio between thesetwo cases.
The only big second-order term is the electron contribution that involves the dipole interaction VI twice.
This term is calculated in the literature only for the Dlike atom model and is scaled according to the electrondensity ratio, although this scaling procedure is unjustified for this term. This term is fairly large andnearly cancels the first-order monopole term for the
D-like atom model, as was predicted theoretically forthis model. 5 )The first-order dipole correction vanishes exactly,
and the largest contribution neglected so far is thefirst-order quadrupole contribution, which vanishes forthe D-like atom model. We reported previously resultsfor [(dtJ1)-d]ee obtained by using an uncorrelated nearHartree-Fock wave function for the D2-like molecule. 6 )In the present work, we have extended the calculations for [(ddJ1)-d]ee , using an elaborate configurationinteraction wave function.
A conspicuous aspect of the results for both [( dtJ1)d]ee and [(ddJ1)-d]ee is that the quadrupole correction
depends on the molecular rotational state and is aslarge as about 1 to 2 meV. Thus, the current excellent
agreement between theory and experiment for [( ddJ1 )d] ee is lost. This is in fact not surprising in view of the
discussion in the third paragraph.
A question arises whether the first-order quadrupoleterm might be also canceled, to some extent, by thesecond-order dipole-dipole term if the latter is calculated accurately without making the usual scaling approximation. It is inconceivable, however, that thiscancellation occurs for all important rotational states
simultaneously, since these two kinds of terms dependon the rotational state in different ways. At any rate,
the present work has proven definitely that the perturbation corrections found in the literature lack in aterm, or perhaps terms, of the order of meV, whether
or not they cancel each other to some extent.
References
1) M. Kamimura: Phys. Rev., A38, 621 (1988).
2) D. Bakalov: Muon Catal. Fus., 3, 321 (1988).
3) K. S. Myint et al.: Z. Phys., A334, 423 (1989).
4) A. Scrinzi and K. Szalewicz: Phys. Rev., A39, 4983
(1989).
5) L. I. Menshikov: Sov. J. Nucl. Phys., 42, 918 (1985).
6) M. R. Harston, I. Shimamura, and M. Kamimura: Phys.
Rev., A45, 94 (1992).

57

RIKEN Accel. Prog. Rep. 27 (1993)

Auger Monopole de-Excitation of
the Muonic Molecule [(ddp,)l,ldee]K, v
S. Hara, M. R. Harston, I. Shimamura, and M. Kamimura
The resonant formation of the muonic molecular ions(dtJ.lh,l and (ddJ.lh ,l through reactions
tJ.l + D2 ---+ [(dtP,)J=1,v=ldee]K,v=2,(1)

dp, + D2 ---+ [(ddJ.l)J=1 ,v=ldee]K,v=7,(2)

plays an important role in the so-called muon catalyzed
fusion processes in hydrogen isotope mixtures. In theabove equations, J and v denote the rotational and vibrational quantum numbers of muonic molecular ionsand K and v, those of the muon molecular complexes[(dtJ.l)dee] and [(ddp,)dee], respectively. The direct fusion rate of the (J = 1, v = 1) state of muonic molecular ions is small because of the large distance between
two nuclei and the fusion mainly occurs in the lower(0,1), (0,0) , and (1,0) states. Such lower states areformed by the Auger transitions

(3)
and

So far, several authors l - 3 ) investigated the Auger
dipole transition rate for reaction (3) in various approximations.
For (ddp,h ,l, the Auger dipole transition does notoccur up to the first order since all the bound statesof (ddp,) molecular ion have the same (gerade ) parity
under inversion of the muon coordinates. Therefore,
the monopole transition (4) becomes the key reaction
for the (ddp,) fusion. The monopole transition rate A
for reaction (4) is given, in the first order perturbation
theory, as follows;

point nucleus with (dee). A detailed explanation of
the interaction is given in Ref. 4. The rotational andvibrational structure of the "D 2 " molecule is properly
taken into account in the frame of the adiabatic nuclei(Born-Oppenheimer) approximation.
In this research, we have calculated the Auger
monopole transition rate of [(ddp,h ,ldee]K,v=7 using accurate muonic wave functions. 4 ) For the initialmolecular wave function Wi , we have adopted the CI
wave function 5 ) which includes 91% of correlation energy. The final state molecular wave function Wf isobtained by the two-centre static exchange approximation.
We have also studied the transition rate for the process(6)
The present results are given and compared with
Lane's result 6 ) in Table 1. The difference between thepresent result and that of Lane is mainly due to thepoor (ddJ.l) wave function adopted by Lane. It should
be noted that for (ddp,)e atom, only the continuum sstate contributes. On the other hand, for [(ddp,)dee]
molecule, both the ~g and ~u continuum states givealmost equal contributions.
Table 1. The Auger monopole transition rate (in 10 8 /sec)
for reactions (4) and (6) from various symmetries of thesystem.

~g
~u

Total

1.0
1.2
2.2

(5)
where ~ and Ware the wave functions for the (ddJ.l)molecular ion and the molecule "D2" (or "Dt + e" forthe final state) , respectively, Vm is the monopole partof interaction potential V and ~ denotes the summation over K' and v'. In Eq. 5, the "D 2 " wave function
is constructed regarding the (ddp,) molecular ion as apoint nucleus positioned at the center of mass of thethree particles. The interaction V is , therefore, thedifference between the actual Coulomb interaction of
the three particles with remaining d and two electrons(dee) and the Coulomb interaction of the "pseudo"

58

References
1) S. Hara: RIKEN Aeeel. Prog. Rep., 25, 63 (1991).
2) E. A. G. Armour, D. M. Lewis, and S. Hara: Phys. Rev. ,A46, 6888 (1992).
3) A. Scrinzi and K . Szalewicz: ibid., A39 , 2855 (1989).
4) M. R. Harston, I. Shimamura, and M. Kamimura: ibid.,
A45, 94 (1992).
5) S. Hara, H. Sato, S. Ogata, and N. Tamba: J. Phys. B:
Atom. MoZee. Phys., 19, 1177 (1986).
6) A. M. Lane: Phys. Lett., 9SA, 337 (1983).

RIKEN Accel. Prog. Rep. 27 (1993)

Experimental and Theoretical Study of Multiple Ionization
Probabilities in 26 MeV Ne4 + + Ne Collisions
S. Lencinas, T. Kambara, S. Kravis, Y. Kanai, M. Oura,Y. Awaya, M. Horbatsch,* and H. Schmidt-Bocking
We report experimental results of scattering-angle
dependence of probabilities of target multiple ionization accompanied by projectile electron loss in NeNe collisions and compare the results with semiclassical Vlasov-IPM (independent-particle model) calculations. We previously reported details of the experimental set-up and data reduction. I)
The Vlasov-IPM is based on a Vlasov equation

at f (r, p, t) + P . V'r f (r, p, t). -V'rVeff(r, t) . V'pf(r,p, t) = 0,

(1)

for a distribution function f(r,p, t) which describes the
motion in the phase space of a single-particle in an effective potential Veff(r, t). It is a semi-classical limit(Ti = 0) of the quantum-mechanical Liouville equation.
In the last decade, this method has been developed andapplied successfully in the theoretical description of
many-body problems of multiple ionization of a target
in collisions with charged particles,2) where perturbative calculations should be invalid.
In the present calculation, the Vlasov equation has
been solved to determine the impact parameter dependence of the charge transfer probability (Px (b)), theone-particle ionization probabilities for the projectile(PL (b)), and that for the target (PI (b)) with a testparticle method which allows to incorporate dynamicalchanges of the binding energies of the target electrons
during the collision. This model does not include ionization due to the interaction between electrons in thetarget and the projectile. However, the contributionof this effect to the total "loss" cross section should besmaller than 20% for the present collision system. If
the ionization of the projectile, that of the target, andthe electron transfer processes are independent singleelectron processes, the probability for the n-fold electron loss of the projectile simultaneous with the production of a q-fold charged target (Pn,q(b)) is expressedwith a statistical formula with the three parameters.
When the electron transfer probability is small, it canbe approximated bywhere the first factor represents the projectile electron
loss and the second one the target ionization.
Figure 1 shows the experimental probabilities of thetarget ionization in the single and double electron-loss
channels of the projectile, compared with the VlasovIPM calculations. Excellent agreement between thecalculation and the experiment in shape and magnitude of the probabilities Pn,q(O) was found for the
single electron-loss channel for the projectile and thetriple ionization of the target (n = 1, q = 3). In the
double electron-loss channel the shape of the probability is well reproduced, however, the absolute magnitude is overestimated by the model. The discrepancies
observed in the small scattering angles below 0.2 mrad
are attributed to the finite resolution of the measured
scattering angle (~O = 0.15 mrad) which is due tothe beam-divergence and the angular resolution of thedetector. The total ionization cross section integrated
over the scattering angle shows a reasonable agreementwith measurements of the total cross section 3 ) within
the experimental errors.
100~~~~~--~~~~~~__ 10- 1•CD'(;)_ 10-2

~ 10-3

Ne 4 + + Ne -- Ne 5 + + Ne3 +(26 MeV)

1O-4bl--+--+--+--I-_-+-_-+-~..- 10- 1
CD•"'iD 10-2
C\ia..

Ne 4 + + Ne -- Ne 6 + + Ne 5 +(26 MeV)
0.2

0.4

0.6

0.8

1.0

8 (mrad)Fig. 1. Ionization probabilities Pn,q((}). Filled circles: Experimental results, full line: Vlasov-IPM calculations.

References
1) S. Lencinas, Y. Awaya, and T. Kambara: RIKEN Aceel.
Prog. Rep., 26, 62 (1992).
2) M. Horbatsch: J. Phys. B, 25, 3797 (1992).
3) H. Tawara, T. Tonuma, H. Kumagai, and T. Matsuo:
Phys. Rev., A41, 116 (1990).

*

Dept. of Phys. and Astronomy, York Univ., Canada

59

RIKEN Accel. Prog. Rep. 27 (1993)

Energetic Electron Production in 20 MeV lu Nq+ and Taq+
Bombarding eu and Fe Thin Foils
Y. Yamazaki, K. Komaki, T. Azuma, K. Kuroki, N. Kakutani, K. Kawatsura,
Y. Awaya, T. Kambara, Y. Kanai, M. Oura, and Y. Nakai
The energy and angular distributions of energetic
electrons emitted in 21 MeV lu N 4 + and Ta37 + ionsbombarding Cu and Fe thin foils (rv 5000A) have beenmeasured with RIKEN Ring Cyclotron.
The final goal of the present experiment is to observe
asymmetry of binary electron intensity for a magnetized (spin polarized) target like Fe. (A Cu target of asimilar thickness is used as a reference to see the affectsof stray magnetic field on the electron energy specta.)
In the present report, we discuss, as a first step, thegeneral behaviour of the electron spectra from suchenergetic ion beams, where the binary electron energy
amounts to several tens ke V.
Figure 1 shows electron spectra d 2 I/dEd n measured
at 0° for 21 MeV lu Nand Ta ions bombarding an Fe
polycrystal foil (rv 5000A). The ordinate is normalized per projectile assuming that average charge statesof the projectile behind the target foil are around 60
and 7 for Ta and N ions, respectively. Each spectrum
shows two peaks, the first one is called convoy electron
peak, which appears at the velocity of the projectile,and the second one is called binary electrons which appears at energies about 4 times larger than the convoy
electrons.
In general, the spectral shape is somewhat common
to both ions except for an area around convoy electrons. (The spectra are not calibrated with respect tothe electron detector (Micro Channel Plate) efficiency,
i.e., the relative intensity between the convoy electron
and the binary peak is not necessarily true.)
It is seen that the binary intensity for Ta ions isroughly 60 times as large as that for N ions, which is60

21MeV / uFe ( 5000A )TaQ+................ ..

'--

•
•

•

•

•

1 0 · · L-~L-~L-~~~~~~~~

o

20

4 0

6 0

Electron Energy (arb. units)

Fig. 1. The electron energy spectra measured at 0° for
21 MeV lu Ta and N ions bombarding a thin Fe foil
(rv 5000A).

about a half of the prediction of a 1st Born calculation,
where the binary electron intensity is proportional to
the the square of the atomic number of the projectile.
On the other hand, the intensity ratio of convoy electrons between Ta and N ions are about 400, which is
crudely the anticipated charge state ratio cubed.

RIKEN Accel. Prog. Rep. 27 (1993)

Double and Single Ionization of Helium at Impact Parameter 0
L. Spielberger, T. Kambara, S. D. Kravis, M. Oura, Y. Kanai,
Y. Nakai, Y. Awaya, and H. Schmidt-Backing
In ionic collisions the mechanisms leading to multiple target ionization are subject of great interest. To
investigate these processes, helium is a well suited target because it is the simplest multiple-electron system.
Several mechanisms are possible for the double ionization of a target He atom by a collision with an ion
projectile: Independent multiple collisions between the
projectile and the target electrons, a single collision between the projectile and a target electron followed byan electron-electron collision, and the emission of thesecond electron due to rearrangement effects in the target atom after a single ionization (shake off).
One of tre main questions concerns the scaling of
the ratio of the ionization probabilitiesr(b) = P(He 2 +, b)/ P(He+, b)(1)

with the charge q of the projectile at a given collision velocity, where P(He H , b) denotes the probability to produce He H ions in a collision at an impact
parameter b. Recent investigations have shown thatthe q2-scaling deduced from an independent-particle
model can be disturbed by higher-order Born terms
or dynamical correlation between both electrons. A
theoretical study of the b dependence of this q-scalingshows that these effects have the strongest influence atsmall b. 1 )In this work the probability ratio was studied in acollision system

In the experiment at RILAC the ionized target He
atoms (recoil ions) were detected in coincidence withthe scattered projectiles. The charge state of therecoil ion was measured with a time-of-flight spectrometer. The projectile ions were charge-state analyzed in a magnet after the target and detected witha position-sensitive parallel-plate avalanche counter(PPAC), which provided the information on the scattering angle. 2) Through the analyses of the charge state(q') of the projectile, we separately observed the channels of the target ionization (q' = 6), the electron loss
(q' = 7) and the electron capture (q' = 5) for the pro-jectile. Some of the projectile ions may get different
charge states before the target through collisions withresid ual gas between the final analyzing magnet of RILAC and the target. These impurity ions were separated by a 'beam-cleaning' system, which consists ofan electrostatic deflector placed just before the target.
It produces a dispersion of the deflection angle among
the different charge states which can be separated on
the PPAC.
Unfortunately the scattering angle information
could not be used in the present investigation due topoor statistics. Therefore we measured the ratio of the
double- to single-ionization cross sections for a charge
state channel q' of the projectile

R(q') = a(He 2 +, q')/a(He+, q')(2)

to get the information of the impact parameter. The
values of R(q') in the different channels are:electron loss
pure ionizationelectron capture(q' = 7)(q' = 6)(q' = 5)42%±2%
5%±O.3%62% ± 2.5%

Since a K-electron is lost in the electron loss channel,
the electron loss is observed mainly in collisions withb smaller than the oxygen K-shell radius, whereas thepure ionization may come from collisions with muchlarger range of impact parameter. The values of R(7)and R(6), in the loss and pure ionization channels, arein a fair agreement with FIM (forced impulse method)
calculations. 1) Especially the ratio observed in the electron loss channel (mainly at small impact parameter b)
is strongly enhanced compared to the ratio observed in
the pure ionization (in a larger impact parameter region), as predicted by the calculations. The q2-scaling
is found to be valid for the present experimental results. The higher value of R(5), in the capture channel,
is not yet fully understood.
References
1) A. L. Ford and J. F. Reading: J. Phys. B, 23, 2567
(1990) .
2) T. Kambara et al.: This report, p. 62.

61

RIKEN Accel. Prog. Rep. 27 (1993)

Target Ionization in 42 MeV Ar 12 + -Ar Collisions
T. Kambara, Y. Kanai, S. Kravis, Y. Nakai , M. Oura, and Y. Awaya
The ionization processes in a fast heavy ion-atomcollision have been experimentally studied through observation of the ionized target atoms (recoil ions).1 ,2)When both the projectile and the target are multielectron systems and the electronic orbits overlap significantly during the collision, the ionization processes
are generally very complicated since they may include
many elementary processes like direct ionization fromthe projectile and the target , electron transfer between
them, and autoionization from their excited states after the collision.
We are interested in the inner-shell ionization andtransfer processes in close collisions where the innershells of the projectile and the target overlap eachother. We study a symmetric collision system:(1)with 42 MeV Ar ions from the RILAC, by measurements of the charge state (i) distribution of the recoil
as a function of the charge state (q') of the projectile
after the collision and the scattering angle () to get the
impact parameter.
The experimental setup is shown in Fig. 1. The
incident Ar 12 + beam was collimated by a pair ofslits with aperture of ±0.3 mm and 4 m aparteach other. The scattered ions from an Ar-gas target were charge-state selected with a dipole magnet
and were counted with a two-dimensional positionsensitive parallel-plate avalanche counter (PPAC). By
the charge-state analyses we observed the projectiles
from one- and two-electron capture (q' = 11 and10), pure ionization (q' = 12), and one-electron loss
(q' = 13) processes separately. The scattering angle
was deduced from the position of the scattered ion on
the PPAC. The slow recoil ions were extracted from
Collimator

Ar Q'~ <-- 4m----.~

Beam
Cleaner

the target region at 90° to the beam direction by anelectric field and charge-state analyzed by a time-offlight spectrometer in coincidence with the scatteredions.
Figure 2 shows the probabilities to produce recoil
ions (i) and the projectile ions (q') simultaneously at
scattering angle () > 0.8 mrad. In this range of thescattering angle, the projectile and the target undergo
substantial overlap of the L-shells during the collision.
The recoil charge (i) has a bell-shape distribution at
i 2 8 with a maximum at about i = 11 and the widthof the distribution is almost independent of q'.
The high recoil-ion charge state (i 2 8) in the close
collisions indicates that almost all the M-electrons
are ionized in the collision and the L-shell processes
mainly determine the charge states of the collisionpartners. We compared the experimental results withan independent-electron model, in which the simultaneous charge state of the projectile and the recoil
ions is determined by independent single L-electron
processes, i.e. , the L-ionization of the target, the Lelectron loss of the projectile and the transfer of a target L-electron to a projectile L-vacancy. The lines inFig. 2 show the results of the calculation. The calculation well agrees with the experimental results except
for the case of a two-electron capture.

(a)1-eca~~ ¥P~~
10- 3 F====F= F==F= .j===I===l====lglO- 1
:.0

2
210o

a:
Gas Targ el_Dipole Magnet

Posit io n
Sensi ti ve
PPAC. . J. __ __. J__ _--l l~Recoi l

TOF
Spectro meter

Ions

Ions

_--¢..--~-- -¢...
//1> Pure lonization " <l>

(b)

/

t

f

_- . .J-- --4 - . --.. . .
1-e Losst ". j

10- 3 '----:8!:-------'------;1""""
1 ="'-----:1"=
2-..1.....--,'
14
0

Recoil Charge Number (i)Fig. 2. Probabilities of target ionization simultaneousto (a) one- and two-electron capture and (b) pure ionization and one-electron loss by the projectile in close
Ar 12 +-Ar collisions.

References
1) C. L. Cocke and R. E. Olson: Phys. Rep., 205, 153(1991).
2) T. Tonuma, H. Kumagai, T. Matsuo, and H. Tawara:
Phys. Rev., A40, 6238 (1989).
Fig. 1. Experimental setup.

62

RIKEN Accel. Prog. Rep. 27 (1993)

Measurement of Radiative Electron Rearrangement X Rays
from 0.8 MeV / amu Ti Ions Excited by Carbon Foil
M. Oura, T. Kambara, Y. Kanai, S. Kravis, Y. Nakai, Y. Awaya, and B. DePaola
We have previously reported a measurement of theKL3 RER (radiative electron rearrangement) x raysfrom 0.8 MeV / amu Ar ions excited by target foil. l )The results have shown that the intensity ratios of KL3
RER line to Ka:L3 line (R3 =: KL3 RER/Ka:L 3) aresmaller than the values obtained from x rays emitted
by excited target atoms. The electronic configurationof L-subshells of fast ions in the foil is expected to bedifferent from that of excited target atoms. Since the
RER intensity is sensitive to the number of 2s electrons, it is expected that the different 2s-2p configuration between the excited projectile ions and the excitedtarget atoms can be studied by the intensity ratio between the RER and satellite x rays.
In order to study the difference in the 2s-2p configuration between projectile ions and excited target
atoms, we have performed two x-ray measurements at
RILAC: one with 1.5 MeV /amu C 2+-Ti and the otherwith 0.8 MeV / amu Ti 5+-C collisions. Typical spectraof Ti K x rays are shown in Fig. 1. Figure l(a) isthe case of target atom excitation and clearly shows
the KLl_, KL2_, and KL3_RER lines in addition to
the Ka:L n satellite lines. Figure l(b) is for projectileions excited by the foil and only shows a small humpat 4.457 keY, which is close to the average energy of
KL3_RER transitions estimated to be 4.462 keY bytheoretical calculation. We attributed the small humpat 4.457 keY to the KL3_RER transition.
The intensities of the KL3 RER and the Ka:L3 were
estimated by fitting procedure in order to compare
the intensity ratio for both projectile ions (R~roj . ) andexcited target atoms (RIar.). The value of this ratio, (R~roj . /RIar.), was 0.6 ± 0.25. This result shows
the KLn-RER x-ray emission probabilities relative to
Ka:L n x rays for excited projectile ions are smaller thanthose for excited target atoms.
In the case of target atom excitation, the multiple ionization is caused by a single collision, and a 2s
vacancy produced can be filled by Ll-L2,3M CosterKronig transitions involving the excitation of M or valence electrons in the solid target before the KLn-RER
transition occurs. On the other hand, the projectile
Ti ions in a target material quickly reach an equilibrium of charge state distribution through successive
outer-shell collisions. 2) The mean number of the L-shellelectrons is estimated to be 4.6 from relative intensities of each satellite lines. It is expected that such
L-electrons are distributed statistically among the subshells, e.g. 2s 22p 3_, 2sl2p4_, and 2so2p5-configurations.
In this case the 2s vacancy produced can be filledca )250000~ 200000
I=l
<0

..c:

~ 150000

...,

{/)

I=l
;::l

o

100000

o

50000

o

500

550

600

650

700

ChannelO.8MeV/u Ti 5+ - - > C
50000......
Q)

~

40000

~

cO

..c:

~ 30000...,~
g 20000
{/)

o

10000

350

400

450

500

550

600

ChannelFig. 1. Ti K x-ray spectra from (a) target atom excitation and (b) 0.8 MeV / amu Ti ions passing through thecarbon foil.

only through the capture processes, because Ll-L2,3M
Coster-Kronig transitions will not occur due to themissing of M-shell electrons. The probability to havetwo 2s electrons, i.e. 2s22p3-configuration, at the emission of the x rays is roughly estimated to be 35% of
possible electronic configurations of 2sn2pffi (n+m = 5,
n :S 2). This probability, however, should be corrected
because the ratio of the capture cross section to theionization cross section for 2s can be estimated to beabout twice that of 2p.
According to the above discussion, the value of(R~roj'/RIar.) is expected to be larger than 0.35. This
explains the experimental result (0.6±0.25) within experimental uncertainty.
References
1) M. Ohura et al.: RIKEN Accel. Prog. Rep., 25, 70(1991); M. Oura et al.: ibid., 26, 60 (1992).
2) T. Mizogawa et al.: Phys. Rev., A42, 1275 (1990).

63

RIKEN Accel. Prog. Rep. 27 (1993)

Binary Encounter Peaks for 0° Electrons in Collisions of Biq +Y. Kanai, Y. Nakai, T. Kambara, M. Oura, S. Kravis, and Y. Awaya
We measured the binary encounter peaks in collisions of Biq + on H 2, He, and Ar at 0° with varying theincident charge state (16+ and 32+) and the incident
energy (0.56, 0.8, and 1.2 MeV/nucleon). In this report, we present the incident charge state dependenceof the binary encounter peak shift and the double differential cross sections of the binary encounter peaks
including the Bi lO +,14+ data reported previously. 1)
The beams of 0.56, 0.8, and 1.2 MeV/nucleon Bi q +from RILAC were magnetically analyzed, collimatedby two sets of four-jaw slits system and focused to thetarget gas cell. The target gas cell was 5 cm in length.
Single collision conditions have verified experimentally.
Figure 1 shows the incident charge state dependence of the binary encounter peak shift l::t.Eb (=4 x Ep x (m/M)-observed peak energy, where Ep is
the projectile energy, m the electron mass, and M
the projectile mass) for the 0.8 MeV/nucleon Bi q +(q = 10,14,16,32) on H 2. The values of the peakshifts for all collision systems are tabulated in Table
1. The calculated shift values by the Bohr-Lindhard
model 1,2) (l::t.Eb = 54.43 X ql/2 x (It!13.6)3/4 X Z~I/6eV), where q is the incident charge state, It the firstionization potential of the target, and Zeff the effective
nuclear charge of the target) are also shown in Table 1.
Here, we use the value of (2 x (first ionization potential
0.8 MeV/nucleon BW + H2

~ 300 Binary Peak Shift

I

;l::

t5 200.;,:;.

<1l

~~

f

I

<1l 100

c

en
10

20

30

Incident Charge State

Fig. 1. The incident charge state dependence of the binary
encounter peak shift.

energy)/27.2)1/2 as the value of Zeff. Absolute valuesof the peak shift and target dependence are qualitatively explained by the B-L model. But, the detail ofthe incident charge state dependence seems to be different from the ql/2 dependence. From our results in
Fig. 1, the peak shift seems to be independent of theincident charge state for Bi 10 +,14+,16+ projectile ions.
The B-L model is originary applied to the bare projectile ions. So, we have to apply this model to the(partially stripped) projectile ions with an ion radius
which is much smaller than the release distance. The
release distance is a characteristic distance in the B-L
model. When the projectile ions come to this distance,
target electrons are released from the target atoms because of the balance between the force from the projectile ions and the binding force to the target atoms.
After that, released electrons collide with the projectile ions as free electrons. The release distance for the
Bi 32 + on H2 is about 5.6 a.u., and the ion radius (meanradius of the outer electron orbit) of the Bi 32 + is 0.5
a. u. On the other hand, the release distance for the
Bi 10 +,14+,16+ on H2 is about 3.2- 4 a.u., and the ion
radius of Bi lO +,14+,16+ is about 1 a.u. and almost constant. From this, we may say that the B-L model isapplicable to the Bi 32 + on H 2, but is not applicable to
the Bi 10 +,14+,16+ on H 2 .
The double differential cross sections of binary encounter electron for Bi q + on H2 and He targets at 0°
and the peak energy are tabulated in Table 2. Absolute values are calibrated by using the He 2+ collisions
with the same collision velocity and the same targets.
In our collision condition, the double differential crosssection increases as the incident charge increases as reported previously. 1)
Table 2. Double differential cross sections of ejected electrons at the binary encounter peak energy observed at
0°. Observed value has about 20% error.
H2 target

Table 1. Binary encounter electron peak shifts at 0° .
Binary Encounter Electron Peak Shift at 0°
H2 target
He target
Ar target
EXp.
B-L.
Exp .
B-L.
Exp.
B- L.
0.8 MeV/ u
Bi lO + 136±20 eV 187 eV 216±40 eV 255 eVeV 190 eV
Bi14+ 132 20
221
212 40302
225
Bi 16 + 136 20
237
219 40323
184±40240
Bi 32 + 268 40
335
382 40456
337 4034 0
1.2 MeV / u
Bi 16 + 127 40
237
210 40323
158 40240
Bi 32+ 230 40
335
397 40456
315 40340~~:fa~~e~r~re 1.065,

64

1.35, and 1.08, respectively, for H2 ,He target

0.56 MeV; u Bi 16 + 1.0 x 10- 18 cm 2 ; ev sr 0 . 7 x 10- 18 cm 2 ; ev sr
Bi 32 + 3.2
1.9
0.8 MeV / u Bi 10 + 0 . 5
0.32
Bi14+ 0. 7
0.42
Bi 16 + 0.8
0.45
Bi 32 + 2.4
1.4
16
Bi
+
0.6
1.2 MeV/ u
0.4
Bi 32+ 1. 2
0.8

References
1) Y. Kanai et al.: RIKEN Accel. Prag. Rep., 26, 65 (1992) .
2) J. O. P. Pedersen et al.: J. Phys., B24, 4001 (1991) .

RIKEN Accel. Prog. Rep. 27 (1993)

Beam-Foil Experiment of Neonlike Iron
K. Ando, Y. Zou, T. Kambara, Y. Kanai, M. Oura, Y. Nakai, and Y. Awaya
We continue to measure the decay curves of 2p 5 3s2p 5 3p and 2p 5 3p-2p 5 3d transitions of the Ne-like ironafter finishing the measurement of Ne-like Ti and Cr
along isoelectronic sequence. The spectrum emitted
from ion beams after passing carbon foil has many
spectral lines as shown in Ref. 1. Among them, only restricted numbers of spectral lines are well isolated andallow a decay curve measurement. Moreover, in thosetransitions of Ne-like ions the lifetimes of 3p and 3d
are almost similar, so that cascading transitions from
3d levels affect the estimation of a lifetime of 3p level.
Therefore, the decay curves of the primary and the cascading transitions must be measured. The analysis ofa decay curve which is affected by the cascading, is carried out by the ANDC (Arbitrary Normalized Decay'
Curve) method. 2 )The measurement has not finished yet. An exampleof the decay curve of the 2p 5 3s (3/2 ,1/2h-2p5 3p 3D3transition at 350.58 A is shown in Fig. 1. The distance
10 mm from the foil corresponds to the flight time ofion of 0.705 ns, since the velocity of iron ion is 14.18mm/ns.

10 1 '-::6~.L......L..J........L....1.....L...1.....L.:-':;1~:-'---'---'----L-'--'.....J.......J--'-::'d~oL.....J-.L....LJ

Foil Position [mm)Fig. 1. A measured decay curve of the 2p 5 3s (3/2,1/2h2p5 3p 3D3 transition of Fe XVII at 350.58 A. The velocity of iron ion is 14.18 mm/ns.

References
1) K. Ando, Y. Zou, T. Kambara, M. Qura, Y. Nakai, Y.
Awaya, and T. Tonuma: RIKEN Aceel. Prog. Rep., 26,
67 (1992).
2) L. Engstrom: Nucl. Instrum. Methods, 202, 369 (1982).

65

RIKEN Accel. Prog. Rep. 27 (1993)

Ejected Electron Spectra from 0 4 +**(18 2 3131')
Y. Kanai, T. Kambara, Y. Awaya, N. Nakamura, M. Koide,
S. Ohtani, H. Suzuki, T. Takayanagi, and K. Wakiya
We carried out a high-resolution measurement of theelectrons ejected from 0 4+** (ls 23131') produced by the
double electron transfer collisions at 60 ke V;
0 6 + (ls2) + T ---+ 0 4+** (ls 23131') + T2+(T = Ar, Ne, and H 2)

L
L

05+(ls22s) + e
05+(ls22p) + e.

60 keY 0 6 + projectile ions were produced by the
ECRIS (Electron Cyclotron Resonance Ion Source) for
the RIKEN AVF cyclotron. Ejected electrons were
measured by the zero-degree electron spectroscopy
technique. 1)
Ejected electron spectra from the doubly excited
04+**(ls 23131') ions are shown in Fig. 1. Vertical lines
in the figure indicate theoretical values, which include

Auger Spectra of 0 4 +** (1 s23131 ')II I I I I

3L -> 2p
3L > 25
1L_ > 2p
1L > 2s

Electron Energy (eV)Fig. 1. High-resolution spectra of ejected electron fromthe doubly excited 0 4 +** (1s 23l3l') ions produced in
0 4 + +Ar, H 2, Ne collisions. Solid and broken lines represent the theoretical energy for the transitions to the05+(1s22p) and 05+ (1s22s), respectively. Upper andlower parts of the lines are for the triplet and singlet
states of the doubly excited states, respectively.

66

a post collision interaction effect calculated from thelifetime. 2) Solid and broken lines correspond to thetransitions to the 05+(ls22p) and 05+(ls22s), respectively. Upper parts of the lines indicate the theoreticalvalues for the ejected electron from the triplet states,
and lower parts indicate those for the singlet states.
Comparing the measured spectra with the theoreticalresults , we can notice following features; (1) The observed spectrum with the H2 target has peaks only
for the singlet states. On the other hand, (2) the observed spectrum with the N e target has peaks only forthe triplet states. (3) Observed spectrum with the Ar
target has peaks for the singlet and the triplet states.
These differences with the different targets must be explained by the double electron transfer processes fromthe target to 0 6 + ions.
The feature (1) is due to that the electronic state of
H2 target is the singlet state and the spin flip does notoccur in this collision. The difference between the feature (2) and the feature (3) may be related to the difference of the excitation energy from the ground state(triple state) to the lowest excited state (spin singlet
state) of Ne 2+ (or Ar 2+) ions. In the case of the Ne
target, the ground state of Ne 2+ is dominantly produced by the double electron transfer to the projectile ions, because of the large excitation energy (3.2eV) from the ground state to the lowest excited stateof Ne 2+. In the case of the Ar target, not only theground state but also the lowest excited states of Ar2+
are produced, because of the small excitation energy(1.7 eV) of Ar2+.
By using the target with many electrons, we canmake the triplet state of the doubly excited ions,as shown in Fig. 1. Especially, the triplet state of
04+**(ls 23131') is made purely by using the Ne target. The detail of the spectroscopic study of the triplet
state is in progress.
References
1) H. A. Sakaue et al.: J. Phys., B24, 3787 (1990).
2) H. Bachau et al.: Atom. Data Nucl. Data Tables, 44,
305 (1991).

RIKEN Accel. Prog. Rep. 27 (1993)

Multiply Charged and Cluster Ions Produced from Gaseous andFrozen CF 4 under Energetic Heavy Ion Impact
H. Shibata, T. Tonuma, T. Matsuo, H. Kumagai , and H. Tawara
In the present work, we have observed multiply
charged atomic and molecular ions and a variety ofpositively charged cluster ions produced from a complex molecular target, CF 4, in gaseous and frozen
phases in collisions with energetic Ar 13 + and Xe31 +ions (rv MeV /amu) from RILAC. Secondary ions produced were extracted, mass/charge-analyzed by a double focusing magnet and detected by a channeltron.
Mass / charge spectra of atomic and molecular ions fromfrozen targets are found to be quite different from thosefrom gaseous targets. For the first time , the parent
molecular ions , CFt, have been observed in the frozen
gas experiment.
Figure l(a) shows a typical mass/charge spectrumof ions from a gaseous CF 4 target in 1.5 MeV / amu
Xe 31 + ion impact. Singly charged CFt molecular ions1~.-~,--.---,--~---,---,---,--.

(a) gaseous CF4

CF;

are seen as a dominant peak, and singly charged CFt,
CF+ , doubly charged CF~+ and CF~+ molecular ionsare also observed in the spectrum. All of these molecular ions are produced in dissociative ionization processes , and no parent molecular ions, CFt (expectedby the arrow in the figure), are observed. In addition to these molecular ions, some multiply charged
atomic ions such as Ci+ (up to i = 3) and F i + (i = 1
and 2) are observed. Relative production of doubly
charged molecular ions and multiply charged atomic
ions is found to be enhanced in ion impact comparedwith that in 500 eV electron impact.I)
Figure 1(b) shows a typical mass/charge spectrum ofions from a frozen CF 4 target in 1.5 MeV / amu Ar 13 +ion impact . The spectrum shows the production ofmultiply charged atomic ions in addition to dominant
singly charged atomic, molecular and a variety of cluster ions. Atomic and molecular ions of Ci+, Fi+ (upto i = 2) , CF+ , CFt and CFt are observed as in
the gaseous CF 4 target described above. It should
be pointed out that the parent molecular ions, CFt ,are observed, which are not seen for the gaseous target. Cluster ions ofFt , C+ (CF 4)n, F+ (CF 4)n,CF~(CF4)n (m = 1- 3, n = 1-3) , CFtC(CF 4 )n ,CFtC(CF 4)n , CFtF(CF 4)n or (CF 4)~+1 and C+C 2 F n(up to n = 4) are also observed.
It is noted that there is a significant difference inmultiply charged ion production between gaseous andfrozen targets: in the gaseous target , the intensities of
Ci+ (i > 1) ions are generally larger than those of Fi+
ions, whereas in the frozen target the intensities of Ci+
ions are smaller than those of F i + ions. This difference
can be understood to be due to sharing of Coulomb
dissociation energy of multiply charged molecular ionswhich results in large initial kinetic energies of multiply charged at omic ions. In CF 4 molecules, C atoms
sit at the center among four F atoms and get only small
kinetic energy. Thus , their intensities are reduced because of low escape probabilities from surfaces.

ct,

frozen CF,

256

CHANNE L NUMBER

Fig. 1. Mass/charge spectra of ions from (a) gaseous and(b) frozen CF 4 targets under 1.5 MeV /amu Xe 3 1+ andAr 13 + ion impact , respectively.

References
1) Ce Ma, M. R. Bruce, and R. A. Bonham: Phys. Rev.,
A44 , 2921 (1991) .

67

RIKEN Accel. Prog. Rep. 27 (1993)

Ions from C 60 /C 70 Fullerenes Deposited on Metallic Foil
under Energetic, Heavy Ion Impact
H. Tawara, T. Tonuma, H. Kumagai, and T. Matsuo
A number of investigations on physical and chemical properties of carbon fullerences and also collision
features are under way. 1) Recently in cto ions colliding with gas targets have observed many dissociation
product ions resulting from the emission of a series of
two carbon atoms (C 2 ).
In the present work, secondary ions from the layersof C60 /C 70 mixtures deposited on metallic foil havebeen observed under 1.5 MeV /u Ar 13 + ion impact.
A thin fullerene target was prepared by dissolving
C60 /C 70 mixtures in toluene, putting a few dropletsof them onto 1 /-Lm Al foil and drying under normal
air. Secondary ion mass spectrum has been obtainedwith a time-of-flight spectrometer. A typical secondary
ion spectrum is shown in Fig. 1; in addition to thedominant peaks of the parent cto (also. Cio and Ct4)
fullerene ions , there are a series of peaks corresponding
to dissociation product ions of these parent fullerenes:
namely, cts, Ct6' Ct4 and so on from C60 (similar ion
peaks from C 70 and CS4 ).

1~~--------------------------~

1 o· 3 ' - - - - - - ' - - - " ' - - - - - ' - - - - ' - - - - - - '
1 0
8
4
o
2

Number of C2 Emitted

Fig. 2. Relative intensities of dissociation ions over theparentions open square: 50 ke V
ions on H2gas. 3 ) solid circles: 1.5 MeV lu Ar 13 + ions incident on
deposited C 60 .

cto

cto

cto ion collisions with H2 targets. As the number of C 2
pairs emitted increases, the relative intensities decrease
more slowly in low energy free cto ions colliding with
H2 than in energetic ion impact on C 60 . This difference
may be due to the presence of the excited cto* ions,compared with the ground state C 60 .
If the successive emission of C 2 pairs is independentof each other, the relative intensities of the dissociation
ions can be given as follows:
R rv pn * (1 _ p)(30-n)

Ion Mass

Fig. 1. Ion spectrum from C 6o lC 7o fullerene deposited on
Al foil under 1.5 MeV lu Ar 13 + ion impact.

It is interesting to compare relative intensities, R,of dissociation product ions over the parent fullerene
ions, which may provide important information on the
dissociation of fullerenes. The present results on Rare
shown in Fig. 2, together with data for 50 keV cto ions
incident on H2 targets. 2 ,3) The relative intensities observed by both groups can be fitted with the followingform:

R rv exp( -a * n)where n (:s; represents the number of C 2 pairs emitted from fullerene and a depends a number of collisionparameters. 3 ) Fitting the observed data gives a = 0.53
for the deposited C 60 layers under 1.5 MeV /u Ar 13 +impact in the present work and a = 0.44 for 50 keV

68

where P represent the emission probability of a single
C 2 pair from the fullerene. As shown in Fig. 2, cts/cto
ratio is estimated to be the order of 0.1 in the present
work (this ratio is 0.07 under 40.8 eV photon impact 4 »)and we can assume P « 1 in the present collision
processes. Thus,pn rv exp( -a* n).

The present analysis clearly supports an assumption3 )that the successive emission of C 2 pairs from fullerene
is independent of each other.
References
1) R. F. Curl and R. E. Smalley: Scientific American, Oct.
issue, p. 54 (1991).
2) A. B. Young, L. M. Cousin, and A. G. Harrison: Rapid
Comm. Mass Spectro. , 5, 226 (1991).
3) P. Hvelplund, L. H. Andersen, H. K. Haugen, J.
Lindhard, D. C. Lorents, R. Malhotra, and R. Rouff:
Phys. Rev. Lett., 69, 1915 (1992) .
4) R. K. Yoo, B. Ruscic , and J. Berkowitz: J. Chem. Phys.,96, 911 (1992).

RIKEN Accel. Prog. Rep. 27 (1993)

Muon Catalyzed Fusion in Thin Solid D2 Layer
K. Nagamine, P. Strasser, and K. Ishida
The production of a slow J-L- beam using the reemission method is not as easily accomplished as the
production of a slow J-L+ beam, since negative muons
injected into condensed matter are captured by atomic
nuclei and form muonic atoms. We proposed a methodof producing slow J-L - beams by using J-LCF phenomena
occuring in a high density D2/T2 mixture. 1 ,2) After
fusion inside a dtJ-L molecule, most of the J-L- do not
stick to the a fusion product but are left free with akinetic energy of several ke V. This liberation process
can be repeated up to 150 times during a J-L- lifetime
and a significant fraction of J-L - can be expected to be
re-emitted from the surface.
The study is now under way by using a D2 layer,
where ddJ-L fusion takes place although much slower
than dtJ-L fusion in D 2/T 2. In order to greatly improve
the re-emission efficiency, we have proposed the twolayer arrangement (Fig. 1) , where the first thick ("J 1mm) layer of H2/D2 (Cd = 0.001) is used for formationand efficient diffusion of "J 1 eV dJ-L atoms 3 ) with thehelp of Ramsauer-Townsend effect, and the second thin("J 1 J-Lm) layer of D2 for the conversion of dJ-L into slow
J-L-.

ergy spectra are shown in Fig. 2 with 8 mg/cm 2 H2/D2(Cd = 0.001) and about (a) 0.16 (b) 0.33, (c) 0.49, and(d) 0.82 mg/cm 2 D2 added to it. The 3-MeV protons
can clearly be seen when dd-J-LCF is produced in theD2 layer. The center of the 3-MeV fusion proton peakis shifted to a lower energy as the D2 layer thickness
is increased due to the proton energy loss. The peak's
width becomes also broader. The ddJ-L fusion yield in
a 1 J-Lm D2 layer is expected to be around 1 S-l froma very preliminary analysis of the 8SB data. A carefulanalysis of these fusion proton data in thin solid deuterium films will bring us a precious understanding of
J-LCF kinetics in the dd system, e.g., dJ-L thermalization
process, ddJ-L mesomolecular formation and ddJ-L fusion.

20
10o ~~~~HH~~++++++~~rrrti:>o 20
~

;; 10
N
-

8-

1tFtt~w..::~~U-.II"

w~~~~~~~~
0 Et-+

~ 20

g 10
U

~~~~~~~o ~~~~HH~44~~++++r+rrrti
1· 10 MeV P_' --11---1'

20
10 ~~'"'"rr"JW,.L.!:::::;.Jlo-AJl...!Y~IO keVp-

Fig. 1. Schematic of slow J-L - production using thetwo-layer arrangement .

As the first step, we carried out an experiment toconfirm the efficient ddJ-L reaction in a thin D2 layer
by detecting 3-MeV protons from the dd fusion. The
experiment was performed at the TRIUMF superconducting muon channel. High energy J-L - (rv 4 MeV)
were injected into a target layer of solid hydrogen
formed by freezing hydrogen gas (H2 and D 2) onto
25-J-Lm silver foil held at 3.5 K. An Si(Li) detector
was used to measure the muonic hydrogen (pJ-L) Ka
X-ray (1.9 keY) when J-L- were stopped in the H2/D2
layer. The J-L- stopping rate obtained at this target was"J 500 s-l.
A Silicon Surface Barrier detector (S8B) was used
to measure 3-MeV fusion protons. Typical SSB en-

Energy [MeV]Fig. 2. Typical SSB spectra with 8 mg/cm 2 H2/D2(Cd = 0.001) and (a) 0.16, (b) 0.33, (c) 0.49 , and (d)0.82 mg/cm 2 D2 added to it.

As the next step, we are planning the detection ofslow J-L - emission using a large-acceptance magnetic
spectrometer. The slow J-L - released from the hydrogen target are collected and focused onto a M ultichannel Plate (MCP) detector. If the production of slow
J-L - beam is succesful, this would initiate a series ofexperiments which are today beyond our technical capabilities.
References
1) K. Nagamine: RIKEN Accel. Prog. Rep., 23, 25 (1989).
2) K . Nagamine, P. Strasser, and K. Ishida: Muon Catalyzed Fusion, 5/6, 371 (1990/91).
3) B. M. Forster et al.: Hyp . Int. , 65, 1007 (1990).

69

RIKEN Accel. Prog. Rep. 27 (1993)

Resonance Ionization Spectroscopy of Fe
H. Katsuragawa, T. Minowa, S. Hashimoto,* and H. K. Uematsu**
Previously we have reported on resonance ionization spectroscopy (RIS) of Fe using a proportionalcounter'!) In this work Fe atoms were supplied by aspark-discharge method. Mass separation of Fe isotopes was impossible because the resolving power of
the TOF mass spectrometer was low.
We have carried out RIS of an Fe atomic beam toseparate Fe isotopes and to observe isotope shifts witha narrow bandwidth dye laser and a high resolution
mass spectrometer. The second harmonic radiation(532 nm) of a YAG laser was focused on an Fe target
in a vacuum chamber to produce an Fe atomic beam.
The laser pulse heated the Fe target up to 10 4 K andvaporized the target. The temperature was estimatedby the velocity distribution of the Fe atomic beam.
The dye laser was fired to ionized Fe atoms resonantlywith a suitable delay after the YAG laser's firing.
A two-stage acceleration TOF mass spectrometer
was used to separate isotopes of Fe ( 54 Fe, 56Fe, 57Fe,
58Fe) . Figure 1 shows a TOF spectrum of Fe+. The
spectrum shows asymmetric line shapes that are probably due to the non-uniform electric field in the accelerator. Relative intensity of each isotope peak is slightly

different from the natural abundance of Fe isotopes.
Although it is reported that ionization yields can depend on mass numbers of isotopes ,2) our result may
be due to the time of flight which each isotope needs
to reach the ionization volume. Irradiation of the dyelaser beam with a suitable delay enables us to increase
only one isotope species of Fe in a TOF spectrum because lighter species reach the detection area earlier.
Ionization peak was observed at 385.590 nm whichcorresponds to the z5 D4-a 5D4 transition of Fe atom
(Fig. 2). This line was observed in the previous work ,too. The resolving power of the present work is improved by two orders of magnitude, which enables us
to measure the isotope shift of Fe.

200
III

~

~

o
u

§ 100
H

til ~O ll­

wavelength(nm)

c:
::1
o
c: !IIOo

Fig. 2. Resonance ionization spectrum of Fe atomic beam.
The ionization peak corresponds to the z5D~-a5D4 transition of Fe.

U
H[S. liIG. 'ITime of Flight(~s)

Fig. 1. Time-of-flight spectrum of Fe+.

*

**

70

385.550385.650+lFaculty of Science, Toho University
Tokyo Gakugei University

References
1) T. Minowa et al.: Rev. Sci. Instrum ., 60, 3280 (1989).
2) P. Lambropoulos and A. Lyras: Phys. Rev. , A40 , 2199
(1989).

RIKEN Accel. Prog. Rep. 27 (1993)

Laser Spectroscopy of Implanted Trace Atoms on a Metal
Substrate: Application of Laser Ablation Ion Trap Method
Y. Matsuo, M. Wakasugi, H. Maeda, and M. Takami
Ion trap is an attractive technique that can confine
ions for a long period of time and can easily be combined with laser cooling or other cooling techniques.
The feasibility of ultra-high resolution spectroscopy inan ion trap has already been demonstrated'!) Ion trap
is also an effective tool for laser nuclear spectroscopy
by means of the precision measurement of hyperfine
structure of rare atoms with unstable nuclei. 2)
We have constructed an rf ion trap system which directly captures ions generated by laser ablation. 3) Thismethod is useful for trapping the ions of heavy refractory metals, multiply-charged ions and implanted trace
atoms on a metal substrate. However, it has been commonly accepted that ions should better be produced
inside of ion trap electrodes because ions transferredfrom outside of the trap electrodes have excess kinetic
energy so that these ions eventually come out of thetrap electrodes. Thus, difficulties were originally anticipated for the direct capture of externally generated
ions. On the other hand, under the presence of lightbuffer gases such as He, ions lose their excess kinetic
energy through collisions with gases. We have applied
this method to the ion trap system and obtained ion
confining times in the range of a few minutes to a few
hours depending on the ionic species.
We also expected that the ion trap with laser ablation method should be applied to the revaporization and ionization of implanted trace atoms. The
atoms with relatively long-lived unstable nuclei are implanted on a metal substrate, which is then placed inan ion trap vacuum chamber, subjected to evaporattion and injection for trapping. We here report a test
experiment of the implantation of trace atoms using
RIKEN IGISOL (ion guide isotope separator on line)
at RIKEN Ring Cyclotron and the revaporization bylaser ablation.
A sample was prepared by implanting heavy metallic ions onto a light metal target at RIKEN IGISOL,
which was used as a mass analyzer with a dedicatedion source. Ba+ ions were produced by the ion source,
accelerated and separated by a magnet so that only theions of 138Ba were implanted onto an Al target within
an area of approximately 50 mm 2. The density of Ba
on the target was estimated to be about 10 12 /mm2 for
120 minutes of implantation with 0.9 nA in current.
Then the sample was placed in the vacuum chamberof an ion trap, revaporized and ionized by YAG laser

ablation and subjected to the laser-inducedfluorescence (LIF) observation. Another important
point in this scheme is that the substrate is aluminum(mass number 27) which has a quite different mass
number from barium. Therefore, the stable conditionof the ion trap for Ba+ ions is unstable for AI+ ions.
Only Ba + ions can be selectively confined.
Figure 1 shows the LIF signal from the trapped Ba + .
LIF was observed after one YAG laser shot, but no LIF
was observed after the second shot. This is because
most Ba atoms in the laser spot (rvO.3 mm 2) were vaporized after the first laser shot. The total number oftrapped ions is estimated to be 104 from the LIF signal
intensity.

LI F of revaporized Ball

.~

C
::J

..0

~
Cl)

u

c

Cl)

u

(f)

~

o

::J

:;::

..1 .1.

Il} ;,

III

after 2nd shot~~~
0.01 nm

455.4

wave length (nm)Fig. 1. LIF spectra from trapped Ba+ ions which were
implanted on an Al substrate and revaporized by thelaser ablation method.

This method will be promising for the laser nuclear
spectroscopy of rare atoms with unstable nuclei. The
efficiency of trapping should be increased by the improvement of experimental arrangement.
References
1) W. M. Itano, J. C. Bergquist, and D. J. W. Winland:
Science, 237, 612 (1987).
2) H. Knab , M. Schupp, and G. Werth: Europhys. Lett.,
4, 1361 (1987).
3) Y. Matsuo, H. Maeda, and M. Takami: Hyp. Int., 74,
269 (1992).

71

RIKEN Accel. Prog. Rep. 27 (1993)

57Fe Mossbauer Studies of YBa2Cu3.92SFeo.0720S
Oriented along the C Axis
T. Okada and K. Asai
A compound YBa2Cu40S is a high-Tc superconductor (so-called 124 compound) with Tc = 80 K. It has
two Cu sites (Cu(l): chain sites and Cu(2): planesites) similar to a 123-superconductor, YBa2Cu307.
In a previous paper,l) a 57Fe Mossbauer study ofYBa2(Cu1-xFex)40S at various temperatures was reported. The spectrum was mainly composed of two
doublets (a) and (b) at room temperatures and magnetically split into two sextets (A) and (B) at low temperatures. The hyperfine magnetic fields (H hf) wereobserved at low temperatures below 40 K , meaningthat the superconductivity and the magnetic order coexisted in that temperature region. By analyzing thespectra in the paramagnetic and magnetically orderedphases, in each iron ion site the two angles 8 between
the principal axis of the electric field gradient (EFG)and Hhf were obtained to be 90° or 35° at (A) sites
and 66° or 45° at (B) sites, respectively. It has been
known that in Cu(2) sites of the 123-compound thez axis of EFG was parallel to the crystalline c axis
and that magnetic moments of Fe ions lay in the Cuo plane (c plane). Since the local site symmetry ofCu(2) was identical in the 123- and 124-compounds,
EFG and the magnetic anisotropy of Fe ions in Cu(2)sites were expected to be similar in both compounds.
Then the angle 8 of 90° was expected. The angle 8of 45° in (B) sites was expected if we assumed that
quadrupole splitting ( QS) was negative with the z axisof EFG lying along a fixed direction in the c plane andthe directions of Hhf were oriented randomly within
the c plane. The (B) site was expected to be Cu(l)sites. The above discussion is very reasonable but includes the assumption that the magnetic moments ofiron ions lie in the c plane. The purpose of this paper is
to clarify the direction of spin in each iron ion site andthe site occupation of iron ions in the compound by using Mossbauer measurements of the powder specimenoriented.
Nobody has succeeded in growing a single crystal of
YBa2Cu4 Os yet. Then, in order to obtain the specimen oriented, at least, parallel to the c axis, the powder specimen was aligned along the c axis in epoxy
by applying a high external magnetic field (14 T)
and sliced into a thin plate of which the plane wasconfirmed to be the c plane by the x-ray analysis.
Mossbauer spectra were obtained with transmission geometry where the incident 'Y ray is perpendicular to the72

c plane of the oriented specimen.
57Fe Mossbauer spectra of the powder (a) and oriented (b) specimens of YBa2Cu3 .92sFeo.o7208 at 4 K
are shown in Fig. 1. Both spectra can be analyzed interms of two magnetically split sextets denoted by (A)and (B), and one doublet (C) in the figure. Here, Fe
ions in the doublet (C) are omitted from the discussion because of their small population. The values ofH hf can be derived to be 425 kOe in (A) and 245 kOein (B) , respectively. Mossbauer intensity ratio of eachpeak in the magnetically split sextet is determined by
the angle between 'Y ray and the direction of spin. The
intensity ratio is 3:2:1:1:2:3 when the direction of spinis random, and 3:4:1:1:4:3 when the incident 'Y ray isperpendicular to the direction of spin. As can be seenin Fig. 1, the difference of Mossbauer intensity ratio of
spectra (a) and (b) is apparently observed. The ratio
is obtained to be 3:2:1:1:2:3 in the powder specimen(a) , and 3:4:1:1:4:3 in the specimen (b) oriented along
the c axis, to which the incident 'Y ray is parallel. It
means that the directions of spins of iron ion sites (A)and (B) are both in the c plane. The present result
indicates that the major part of Fe ions occupies theCu(2) sites and the minor the Cu(l) sites.

c

o

.~

99

'E

(j)

c

at random~1
00uaa~
••••
W
.
(b)
ro
a>

\t

~

a: 99

(8), '
(A)

- 10

I

I

(C)u
I

orientedI

0

Velocity (mm/s)+10Fig. 1. 57Fe Mossbauer spectra of the powder (a) and theoriented (b) specimens at 4 K.

References
1) T. Okada et al.: Nucl. Instrum. Methods Phys. Res. ,B76, 338 (1993).

RIKEN Accel. Prog. Rep. 27 (1993)

Charge State and Diffusivity of Hydrogenic Atomin GaAs with Si Donors
R. Kadono, s. Fujii,*l A. Matsushita, K. Nagamine, K. Nishiyama,*2 and S. Tanigawa*3
Since the revelation in the early 1980s that hydrogen can form chemical complexes with impurities including carrier dopants to eliminate electronic states insilicon (Le., hydrogen passivation), the structure andkinetics of hydrogen isotopes in semiconductors havebeen drawing much attention.1) However, while microscopic information on hydrogen-impurity complexes
has been obtained by means of infra-red spectroscopy
and channeling, relatively little is known about theisolated hydrogen state in semiconductors. It is noteworthy that p,SR (Muon Spin Rotation, Relaxation,
Resonance) has made a significant contribution to thelatter by clarifying the electronic structure of isolated
muonium state (a muonic analog of hydrogen atom inwhich proton is substituted by positive muon) in bothelemental and compound semiconductors. 1,2) Furthermore, the recent development of longitudinal spin relaxation technique for the muonium state has provided
information on the diffusion property of isolated muonium in high-resistivity (HR) GaAs.3)
We report on the effect of silicon (Si) doping on the
charge state (MuO,±) and kinetics of muonic states
in GaAs. The p,SR measurements were performed
at UTMSL (Meson Science Laboratory, University ofTokyo) on two GaAs samples grown by the horizontal
Bridgman method with different doping levels, havingroom temperature carrier concentration of 10 12 _10 14
cm- 3 (GaAs:Si-A, non-metallic) and 9 x 10 17 cm- 3(GaAs:Si-B, metallic), respectively.
The implanted positive muons are known to form
two paramagnetic centers in GaAs discerned by the hyperfine structure, Le., interstitial muonium (Mu) andbond-center muonium (Mu*). In addition, a diamagnetic muon (Mu±) state is observed in doped GaAs,
which is predominant in metallic samples. The current data indicate that the M u state in non-metallic
GaAs is replaced by Mu± in metallic GaAs probably
due to the increased Fermi level, whereas Mu* state is
only weakly affected by doping. Moreover, the changeof the charge state was found to strongly influence thediffusion property of the muonic states as shown in Fig.
1. Namely, Mu is highly mobile in non-metallic GaAs

with Dp, = a 2 /32Tc ~ 10- 8 - 10- 6 cm 2 S-l, where
the effect of weak doping is seen only below 30 K in
GaAs:Si-A. Meanwhile, the jumping frequency of Mu±
in GaAs:Si-B is less than 106 s-l over the temperature
range 4-300 K, being three orders of magnitude lower
than that of Mu in non-metallic GaAs. Moreover, theMu± state seems to be immobile at room temperature, suggesting that the state is deeply trapped or ina bound state with impurity atoms.

!D

rn

$

II!
!B

J

o

o
o

'I

~

~o 109
~

10
10

•

8

6

b)

MUd

in GaAs:Si
17

n:10 em-tt

3

4

10 3~~5~~1~0--~2~O~~5~0~1~0~O-~2~0~03~00

TEMPERATURE (K)Fig. 1. The jumping frequencies of a) Mu in HR-GaAs(open squares, after Ref. 3 and in GaAs:Si-A (filled circles), and b) Mu± in GaAs:Si-B.

References
1) For a recent review, see, for example, J. 1. Pankove andN. M. Johnson eds.: Hydrogen in Semiconductors, Academic, San Diego (1991).
2) For a recent review, see, for example, B. D. Patterson:
Rev. Mod. Phys., 60, 69 (1988).
3) R. Kadono et al.: Hyp. Int., 64, 635 (1990).

* 1 Sumitomo Electric Industries Ltd.
*2 Meson Science Laboratory, University of Tokyo*3 Institute of Material Science, University of Tsukuba
73

RIKEN Accel. Prog. Rep. 27 (1993)

Annealing Behaviour of Kr Atoms in Kr-Implanted Aluminium
M. Hacke and E. Yagi
It has been demonstrated that heavy inert gas atoms(Ar, Kr, and Xe) implanted into metals at ambient
temperature precipitate into bubbles, and that for highimplantation doses they are in a solid phase epitaxiallyaligned to matrices. I - 3 )From previous channelling studies on the Krimplanted AI, we obtained the following results. At theinitial stage of implantation various types of complexes
consisting of Kr atoms and vacancies (V) such as Kr V 4,
KrV6 and larger ones are formed, and act as nucleation
centres for the subsequent bubble formation. 4,5) The
formation of solid krypton is enhanced by the postimplantation irradiation. 6) The objective of the present
study is to investigate the behaviour of Kr atoms inaluminium for annealing and the stability of the Krvacancy complexes by the channelling method.
Kr+ implantation was carried out at room temperature at 50 keY with a dose of 10 15 Kr/cm 2 at a dose
rate of about 2.2 x 10 12 Kr/cm 2 s (specimen A) or
3.2 x 10 12 Kr/cm 2 s (specimen B) , The specimen A was
isochronally annealed at 373, 433, 473 , 523, and 593
K for 30 min. After each annealing treatment channelling analysis was performed at room temperaturefor <100> , <110> , and <111> channels with a 1.0
MeV He + beam accelerated by a tandem accelerator.
In the as-implanted state the Kr angular profile exhibits a shallow dip with nearly the same half-width
as that of the corresponding channelling Al dip for t he<100> and <111> channels, and a central peak superimposed on a shallow dip for the <110> channel.
In the <100> Kr profile a very small central peak issuperimposed on the dip. As previously reported, 4- 6)
these profiles can be interpreted as showing that the
Kr atoms are distributed over substitutional (8), tetrahedral (T) (Kr in KrV 4 ) , octahedral (0) (Kr in KrV6) ,and random (R) sites. The small <100> central peakoriginates from the T-site occupancy, and the <110>
central peak from the T- and O-site occupancies.
Upon annealing at 433 K , the small <100> central
peak disappears, and either of the <100> and <111>
Kr profiles exhibits a shallower simple dip with nearly
the same half-width as that of the corresponding Al
dip. The <110> central peak is still observed. These
results indicate that upon annealing at 433 K the Tsite occupancy disappears but the O-site occupancy is
still present. On annealing at 473 K a small portion of
Kr atoms which have been located at the 0 sites areslightly displaced.
Upon annealing at 593 K the <110> central peak
disappears, and any of the <100>, <110> and <111>
Kr profiles exhibits a very shallow dip of the relative74

depth of approximately (3- 8)% of the corresponding Al
dip, indicating that the O-site occupancy disappears
and most of Kr atoms (rv 95%) are located at R sites.
From the observed angular profiles the fractionsof various site occupacies were estimated. They are
shown in Fig. 1. The annealing stages at 433 and 593
K are explained in terms of the dissociation of KrV 4
and Kr V 6 complexes, respectively.

1.0 ..,--- - - - -- - - -- - - - - - ,(j)w~ 0.8 -ow

~ 0.6oR~oo~ 0.4 -

Zot3 0.2<{a:l.L.

0.0200

I

I

I

I

300

400

500

600

TEMPERATURE [KJ

Fig. 1. The change of t he fractions of various site occupancies with the annealing temperature. In two cases ofannealing at 473 and 523 K the open squares represent
the sum of the fractions of the 0- and displaced O-site
occupancies.

The specimen B was annealed at 683 K after similar
isochronal annealing up to 593 K. The Kr profiles are
significantly different from those obtained after annealing up to 593 K . For the <110> channel it exhibits ashallow dip approximately 1.5 times broader than the
Al dip. This broader Kr dip can be explained by thechannelling effect of the incident He+ ions in an epitaxially aligned solid Kr crystal lattice, because thecritical angle for channelling is larger for the Kr crystal than for the Al crystal. Therefore, on annealing at
683 K , solid krypton is formed.
References
1) A. vom Felde, J. Fink. Th. Muller-Heinzerling, J.
Pfluger, B. Scheerer, G. Linker, and D. Kaletta: Phys.
Rev. Lett., 53, 922 (1989).
2) C. Templier, C. Jaouen, J. -Po Riviere, J. Delafond, andJ. Grilhe: C. R. Acad. Sci. , Ser. II, 299, 613 (1984).
3) J . H. Evans and D. J. Mazey: J. Phys. , F15 , L1 (1985).
4) E. Vagi: Nucl. Instrum. Methods Phys. Res., B39, 68(1989).
5) E. Vagi, 1. Hashimoto, and H. Yamaguchi: J. Nucl.
Mater., 169, 158 (1989).
6) E. Vagi: Phys. Rev. Lett. , 67, 3804 (1991).

RIKEN Accel. Prog. Rep. 27 (1993)

High Energy Heavy Ion Irradiation ofSuperconductor La2-xSrxCu04
M. Terasawa, T. Mitamura, T. Kohara, K. Veda, H. Tsubakino, A. Yamamoto,*
Y. Awaya, T. Kambara, Y. Kanai, M. Oura, and Y. Nakai
Ion irradiation on oxide superconductors degrades
the superconducting transition temperature (T c) anddecreases the critical current density (Jc) at a highion fluence regime, where the material undergoesa superconducting-to-nonsuperconducting transition
due to the defect accumulation. However, there is apossibility that the high energy heavy ions can enhance
J c at fairly low flunece through the interaction of ioninduced defects with the flux lattice. 1) In this work weinvestigated the effects of high energy and heavy ion
irradiation on La1.8SSrO.lSCu04.
Sintered polycrystalline specimens of La1.8SSrO.lSCU04 were prepared by means of the conventional ceramic procedure. The specimen of 10 mm in diameter and 0.5 mm thick were thinned to less than 0.15mm so that incident ions can penetrate throughout
the specimen full depth. The specimens were irradiated with 3.5 Ge V 136Xe31+ ions from the RIKENRing
Cyclotron. After the irradiation electrical resistivity
measurements were made by a conventional four pointprobe method. The measurement was performed byapplying a magnetic field in the way that the direction of incident heavy ions is parallel to the appliedmagnetic field.
From the I - V measurements by the four pointprobe method was decided a critical current density
J c at which a sharp increase in voltage was observable.
Without application of the magnetic field, J c was 35
AI cm2 and 76 AI cm2 for the unirradiated specimen
and for the specimen irradiated to 1.2 x lOll Xe/cm 2 ,respectively. With application of the magnetic field ,the unirradiated specimen showed a drastic decreaseof J c , while the present Xe-ion-irradiated specimens
showed no J c change (1.2 x lOll Xe/cm 2 ) or gradualdecrease (3.0 x lOll Xe/cm 2 ). Figure 1 shows J c as afunction of the applied magnetic field for the Xe irradiated and unirradiated specimens. The J c data werenormalized by the current densities at zero magnetic
field for each specimen. Remarkable irradiation effecton the critical current density was observed.
High resolution transmission electron micrographs of

*

La

1.85

Sr

CuO

0 .15

4

0.8
o
(J

...., 0.6

_Unlrradiatedu_1.2x10 11/cm 2

JO.4_3.0x1(l 11/cm 2

0.2
00

0.02

0.04

0.06

0.08

0.1

0.12

Magnetic Field, T
Fig. 1. Critical current density as a function of the appliedmagnetic field. The current density is normalized by theone, J co , without magnetic field.

the irradiated specimens revealed that the ion-induced
damage comprises an amorphous columnar structure
along the ion track. The columnar damage is about 5
nm in diameter on average, and the density is almost
the same as that of the ion fluence.
In conclusion, radiation effects of GeV heavy ions on
La1.8SSrO.lSCu04 were investigated for the first time.
It is confirmed that the electron transport properties
are improved and that the increase in J c over 10 times
the one before irradiation is obtainable with no degradation of the critical temperature T c even in the magnetic field application. The columnar defects inducedby the GeV heavy ions through an electronic stopping
interaction may affect primarily for pinning the magnetic flux. Since the ion fluence is extremely low, deleterious effect against weak links between the superconducting grains, which has been a problem in theconventional neutron or proton irradiation resulting in
T c and J c degradation, will be negligibly small in the
Ge V heavy ion irradiations.
References
1) L. Civale et al.: Phys. Rev. Lett.) 67, 648 (1991).

Himeji Institute of Technology

75

RIKEN Accel. Prog. Rep. 27 (1993)

Single Event Effect in Power MOSFETs andCMOS ICs by High-Energy Heavy Ion
S. Matsuda, S. Kuboyama, T. Tamura, Y. Shimano, M. Nakajima, M. Uesugi, T . Kanno, J. Ohya,
T. Ishii, H. Ohira, T. Kohno, N. Inabe, T. Nakagawa, M. Kase, A. Goto, and Y. Yano
Power MOSFETs and CMOS ICs are essential devices for power switching and digital processing, respectively.
However, they have a possible catastrophic failure mode known as Single Event Burn-Out(SEB)/Single Event Latch-up (SEL) triggered upon incidence of high-energy heavy ions. Since this is an
important phenomenon to be considered in space electronic applications, there is necessity to improve theimmunity from these Single Event Effect (SEE) for thecommercial devices.
To study the SEE mechanism, a spectrum of chargecollected in the device was measured by a pulse-height
analyzer system with a modified charge-sensitive amplifier. In previous work for Power MOSFETs,l) it
was suggested that SEB was triggered when a collectedcharge exceeded some threshold charge QTH' Figure
1 shows the charge spectra for several samples of different rated drain breakdown voltage (BY DS)' It is
obvious that each sample has its own peculiar QTH.
Detail of QTH is defined in reference. 2) It has been
also identified that the 1st and 2nd peaks correspondto the collected charge from a drain junction and theinjected charge from a source junction, respectively.

2nd peak
1st pe~k
/

.'

---U'

A a THSEB
Signal

BVos

I
~.
800V
-I+----..&...- 500V

Table 1. Parameter of heavy ions.
Xe
Ion
Ar
Kr
Energy [MeV / u]
95
10
26
2
LET in Si
29
36[Mev·cm 2 /mg]
Range in Si [J.Lm] 6000 104 240* Data obtained in previous work

Ni*

4.3
30
32

Calculated energy loss (~E) in the depletion region
when SEB starts triggering is shown in Table 2. The
depletion region was calculated based on the impurity
density. Since no SEB was detected at the incidenceof Ar ion, ~E at the maximum rated voltage is shownin case of Ar ion. SEB is t riggered when the energy
loss ~E in the depletion region gets beyond a certain
value for each device.
Table 2. Energy loss in the depletion region of power
MOSFET when SEB is triggered.
DeviceRated BV DS [V DC]~E [Me V] by Xe ion~E [Me V] by Kr ion~E [MeV] by Ni ion~E [Me V] by Ar ion* no test data

A

B

60
22
19
20

250
92

(1.8)

90
(11)

C
500
200
194
200
(17)

A-J\

I

III

E
::I

,
1\ I
1-1
'Y--_...A..-I

o

(J
III

:;
Q.

I

_ _- A - -

'

250V

' - - I - - - - L - - - 120V

_ _'-',~ , "+-_ _ _.A...--_ _ 60V
1 0-'

1 00

1 0'

1 02

1 03

1 ()4

1 05

1 Q6

Collected charge [pC]

Fig. 1. Collected charge spectra by Xe ion irradiation forvarious rated voltage samples. I)

High-energy heavy ions from RIKEN Ring Cyclotron were utilized this year to analyze the dependence of QTH on BY DS and LET of ions. The parameters of heavy ions are shown in Table 1.

76

In the meantime, several CMOS ICs for space application including SRAM, Gate-Array, etc. were submitted to the experiment of SEL. Improvement of immunity from SEL was demonstrated by the experimental data. Moreover, it was suggested that the threshold LET of 64 Kbit SRAM for commercial use was 2
MeY·cm 2 /mg.
For further study of Single Event Effect , more detailed analysis will be performed concerning the dependence of charge creation on supply voltage of devices.
References
1) S. Matsuda et al.: RIKEN Accel. Prog. Rep., 26, 75(1992).
2) S. Kuboyama et al.: IEEE Trans . Nucl. Sci., NS-39,

1698 (1992).

3. Radiochemistry and Nuclear Chemistry

RIKEN Accel. Prog. Rep. 27 (1993)

Preparation of a Radioactive Multitracer Solution from Iron Foil
Irradiated by 80 MeV/nucleon 16 0 Ions
S. Chen, S. Ambe, and F. Ambe
We reported previously radiochemical procedures toprepare radioactive multitracer solutions free from carriers and salts by using Au, Ag, and Cu targets irradiated with a 12C, 14N, or 16 0 beam. 1,2) The Cu
target is suitable for preparing a multitracer solutionof lighter elements. However, the preparation methodfrom the Cu target takes a relatively long time to complete. Therefore, a more convenient method of preparing a radioactive multitracer solution from an Fe target
irradiated with a heavy-ion beam has been developed.
Three sheets of Fe foil (24 mm0 x 100 J-lm) mounted
in a 40 mm0 aluminum ball with a 20 mm0 piercing hole were irradiated with an 80 MeV/nucleon 16 0
beam in the falling ball irradiation system installed
in a beam course of the RIKEN Ring Cyclotron. 1)
The beam intensity was about 50 enA and the irradiation time was about one hour. The beam profile
was roughly 10 x 10 mm.
The irradiated Fe foil (200 mg) containing various
radioactive nuclides produced by the heavy-ion reactions was dissolved in 4 cm3 of conc. HCI. Fe 2+ inthe solution was oxidized to Fe 3 + with 1 cm 3 of hydrogen peroxide. Distilled water was added to the solution in order to adjust it to 6 mol dm -3 in HCI. The
resultant solution was passed through a 10 mm0 x 10
cm anion exchange column of Diaion SA#100, 100- 200
mesh pretreated with 6 mol dm -3 HCI. Radionuclides
were eluted with 6 mol dm- 3 HCI. The first 40 cm 3 ofthe effluent was evaporated to 2 cm3 under a reducedpressure of about 4 kPa in a rotary vacuum evaporaterto yield a carrier- and salt-free multitracer solution.
The ,-ray spectra of the irradiated Fe foil , each effluent, and the multitracer solution were measured using
pure Ge detectors. The spectra were analyzed with aversion of the BOB code 3) on a FACOM M1800 computer at RIKEN.
The nuclides found in the multi tracer solution were
7Be, 24Na, 28Mg, 42K, 43K, 44 m Sc , 48V, 48Cr, 51Cr,
52Mn, and 54Mn. No ,-rays due to the radionuclidesof iron produced in the target foil (52 Fe etc.) weredetected in the spectrum of the multitracer solution.
This indicates that Fe was completely separated by theabove anion exchange procedure.

Figure 1 shows representative elution curves throughthe anion exchange column with 6 mol dm- 3 HCI.
Their behavior agrees well with the distribution coefficients of those elements between an anion exchanger
and 6 mol dm- 3 HCI. 4)~.-------------~

Mg·28

1779. IK.V

120..---:;'7':.: - - - - - - - - - - - ,
100

60

K·43

396.9K.v

80

40

60

20

~
<Il

~

5

10

15

20

25

30

35

40

:,1
5

10

15

20

25

)0

5

10

15

20

25

30

35

40

35

40

I~r--------------~

;:::l

8

5

10

15

20

25

30

)5

em3

40

em3

Fig. 1. The representative elution curves of radioactive
nuclides produced in the iron target with 6 mol dm- 3
Hel through an anion exchange column.

The present method of preparation of the multitracer solution from an Fe target by means of anion
exchange takes only about 2 hours to complete. The
useful radionuclides in the solution from an Fe target
are essentially the same as those from a Cu target except for 52Fe, 61Co, and 62Zn. Therefore, the present
method using an Fe target is superior to that using
a Cu target 2) and is especially profitable in studies of
nuclides of a relatively short half-life.
References
1) S. Ambe et al.: Chern. Lett., 1991, 149.
2) S. Ambe et al.: Anal. Sci., 7, Suppl., p. 317 (1991).
3) H. Baba et al.: J. Nucl. Sci. Technol., 8, 1227 (1972).
4) K. A. Kraus and F. Nelson: Proc. Int. Conf. PeacefulUses Atomic Energy, Geneva, 7, 113 (1955).

77

RIKEN Accel. Prog. Rep. 27 (1993)

Observation of Complex Formation of a Numberof Metal Ions with Tea Extracts
W. Li, S. Ambe, Y. Ohkubo, M. Iwamoto, Y. Kobayashi, H. Maeda, and F. Ambe
Recently, the radioactive multitracer technique has
been extensively applied to a variety of research fields
due to its advantages over the conventional tracer
techniques. 1) In this report, we brief results of a preliminary study on complex formation of metal ions withtea extracts using the technique. The results are significant in relation to the ingestion ()f metal elements
by human being.
A portion of radioactive multi tracer solution, obtained from irradiation of an Ag target with 80
MeV /nucleon 16 0 ions, was twice evaporated gently
to dryness in order to remove all the inorganic acidcomponents. The residue was dissolved in diluted tea
extracts prepared as described below. Four different
kinds of tea, Japanese green tea (labeled as JG), Chinese green tea (CG), Chinese Wulon tea (CW), andChinese black tea (CB), were used. Half a gram of each
was added to 40 cm 3 distilled water. The suspension
was heated to keep slightly boiling for 20 min. After
filtration and centrifugation, the tea extracts (about
30 cm 3 ) were ready for the experiment. In case of
studying the concentration dependence of distribution
coefficients K d , 2 g of Japanese green tea was treatedin the same manner to yield a stock solution of thetea extract. We denote the concentration of the stock
solution as C (arbitrary unit). The tea extracts withdifferent concentrations were obtained by dilution of
the stock solution with distilled water. For comparison, 0.1 mol dm- 3 HCI0 4 and 0.02 mol dm- 3 DTPA
solutions were also used. The pH values of these solutions were adjusted by NaOH to the values close to
those of the tea extracts.
A conventional ion exchange method using Dowex
50W-X8 resin (100-200 mesh, Na-form) was employed
to study the complex formation. About 30 mg of theresin (kept in equilibrium with a saturated NaCI solution) was added to 8 cm 3 of the tea extracts containing
the multitracer. The suspension was shaken at 25°C
for 1 h. After centrifugation of the suspension, thesupernatant solution was withdrawn for ')'-ray spectroscopy with a pure Ge detector. The measurementsof ')'-ray spectra lasted for two weeks in order to covera wide range of half-life of radioactive nuclides.
The adsorption percentages were determined for 14
elements in this experiment. Se(IV) and Tc(VII), existing generally in a form of negative ions, as well as
Ru(III) or Ru(IV) and Rh(III) showed very low percentage of adsorption (typically less than 10%) for allof the solutions under study. The other metal ions,however, were adsorbed by the cation exchange resin
to different extent. The adsorption percentages for se-78

lected metal elements are given in Table 1.
Table 1. Adsorption percentages by cation exchange resin.
Element JG(pH)(5 .9)
Be
7.1
Mn
52
Co
20

CG
(5 .8)
3.2
55
19

Rb

56

56

Sr
Y
Zr

34
31
10

49
27
18

CW
(5.2)

3.8
44
40
58
27
37
5.0

CB
(5.2)
8.7
48
42
64
48
34
11

HCI04
(5.7)
26
49
58
24
47
40
51

DTPA

(5.9)
3.6
27
3.0
36
49
2.0

o

The complex formation between the metal ions and
HCI0 4 is regarded to be negligible. From Table 1, we
can see that the adsorption percentages of the majorityof metal ions in the tea extracts are less than those in
HCI0 4 solution, indicating formation of certain kindsof complexes between these cations with the tea extracts. Rb can form a compound with HCI0 4 , leading
to the decrease of the adsorption in a HCI0 4 solution.
Zr and Be formed more stable complexes with the tea
extracts than Mn and Sr did. There is no much differece in the adsorption percentage among four kindsof tea extracts. The stability of the complexes of thetea extracts with the cations is not very large whencompared with those of DTPA. Log-log plots of apparent Kd values versus the concentration of the extracts
from Japanese green tea for Rb, Sr, and Co are shownin Fig. 1. As was expected, the Kd values decrease
with increasing extract concentration.
1000 , . - - - - - - - - - ,

o Rb
o

•

0

A

~ 100

A

A

Sr
Co

•

I~OLI~.............
. I~-""-I~""""""'10
C (arb. units)

Fig. 1. Dependence of Kd values on the concentration oftea extracts.

References
1) S. Ambe et al.: Chern. Lett., 1991, 149; 1992, 1059;
S. Y. Chen et al.: Anal. Sci., 7, Suppl., 1105 (1991);
S. Ambe et al.: ibid., p. 317; M. Iwamoto et al.: ibid.,
p. 313; S. Ambe et al.: Appl. Radiat. Isot., 43, 1533
(1992); S. Y. Chen et al.: J. Radioanal. Nucl. Chern.
Lett. , in press.

RIKEN Accel. Prog. Rep. 27 (1993)

Production of Multitracer Nuclides by
Irradiation with a 84Kr Beam
M. Iwamoto, S. Ambe, Y. Ohkubo, Y. Kobayashi, H. Maeda, and F. Ambe
We have been producing multitracers using C, N,
0, and Ar ions accelerated by RIKEN Ring Cyclotron
in these years. Separation of multi tracers from targets is performed by radiochemical procedures or byheating under a reduced pressure. I - 5 ) In these methods, each target material requires a specific elaborate
treatment. If much heavier ions are used as projectiles
in combination with different targets and catcher foil
for production of multitracer nuclides , it is expectedthat a large part of product nuclides are recoiled outof the target and can be collected by catcher foil placed
behind the target. Using appropriate catcher foil of acommon material, the same simple separation method
is available for different targets. Some results of a preliminary experiment on this course is reported.
The target was Ti-, Cu-, Nb-, Ag-, Ta-, and Au-foil
and the catcher was 25 mm-thick Al foil. The target assemblies were irradiated by 10.5 MeV/nucleon 84Kr13+
ions using Falling Ball Irradiation System. 1) The average beam intensity was 10- 30 enA and irradiation time
was about 1 h. Details of experimental conditions fordifferent targets are summarized in Table 1.
After the irradiation, the target and catcher foil wereanalyzed by direct ,-ray spectroscopy with pure Ge-

detectors. Yield calculation of product nuclides wasmade by BOB code6 ) and related programs. Assignment of the nuclides was performed on the basis of theenergy of ,-rays and half-life.
Table 2 shows the fraction of various nuclides foundin the catcher foil, that is the yield in catcher foil divided by the total yield . It is seen from Table 2 that allof the identified nuclides with a mass number exceedingthat of the projectile (84) are exclusively found in thecatcher foil. The high yield of 24 N a in the catcher foil
is ascribed to fragmentation of 27 Al nuclei in the foil.
These preliminary results already demonstrate the effectiveness of this catcher foil method. Analysis of thedata on the other target assemblies is under way.
Table 2. Fractional yield in the catcher foil for the Ti
target.
NuclideNa-24
K-43
Sc-44m
Rb-81
Y-86
Zr-86
Zr-89

Fr. Yield
0.91
0.22
0.21
1.0
1.0
1.0
1.0

NuclideNb-90
Mo-93m
Tc-95
Ru-97
In-109In-110m
In-ll1

Fr. Yield
1.0
1.0
1.0
1.0
1.0
1.0
1.0

Table 1. Experimental conditions.
Target
Ti
Cu
Nb
Ag
Ta
Au

(~m )

Duration
( h)

20
20
12.7
10
10
25

1.04
1.01
1.01
1.01
1.03
0.98

Thickness

Total current( ~tC)
55.2
72.6
37.6
96.1
80.4
26.4

References
1) S. Ambe et al.: Chern. Lett., 1991, 149.
2) S. Ambe et al.: Anal. Sci., 7, Suppl., p. 317 (1991).
3) M. Iwamoto et al.: ibid., p. 313.
4) S. Ambe et al.: Appl. Radiat. Isot., 43, 1533 (1992) .
5) S. Y. Chen et al.: J. Radioanal. Nucl. Chern. Lett. , inpress.

6) H. Baba et al.: J. Nucl. Sci. Technol., 8 , 1227 (1972).

79

RIKEN Accel. Prog. Rep. 27 (1993)

Transport of Tc(VII) and Re(VII) througha Supported Liquid Membrane
S. Ambe, Y. Ohkubo, Y. Kobayashi, M. Iwamoto, M. Yanokura, H. Maeda, and F. Ambe
Technetium-99 with a long half-life (T 1/ 2 = 2.1 X 10 5y) is widely distributed in both geo- and hydrosphere.
Determination of 99Tc in the environment is an important subject. For environmental samples , concentration of 99Tc from a large volume is required for its
exact determination.
Separation of metal ions by means of supported liquid membranes is now being viewed with keen interest
as an efficient analytical tool. The method is considered to be especially suitable for preparation of radioactive tracer solutions because of (1) the simplicity
of operation leading to facile automation, (2) the feasibility of concentrating tracers into a small volume of asolution, and (3) the necessity of a far smaller amountof extractants than in the case of conventional solvent
extraction, resulting in little organic radioactive waste.
This paper describes the successful transport ofTc(VII) and Re(VII) from acid solutions to alkaline
solutions by means of a TBP-decalin membrane supported on a microporous polytetrafluoroethylene sheet.
Tc* and Re* produced in the Au target irradiatedwith a 135 MeV/nucleon 14N beam were used as tracers. After chemical treatment of the target, a solution
containing Tc* (VII) and Re* (VII) was used as a feedsolution which was 0.12 mol dm- 3 NaCI and 0.04 mol
dm- 3 NaN0 3 ·The micro porous polytetrafluoroethylene sheet usedas the support for TBP-decalin was Fluoropore FP045 (Sumitomo Electric Ind.) with an average poresize of 0.45 j.lm, 75% porosity, and 0.08 mm thickness.
A 24 mm¢> supported liquid membrane was preparedby impregnating the sheet with a TBP-decalin (3:1) solution. Distilled water or 0.5 mol dm- 3 NaHC0 3 wasused as a strip solution. The supported liquid membrane was fixed at the bottom of a Teflon vessel witha Teflon ring. The feed solution in an outer vessel was
stirred at 400 rpm with a magnetic stirrer. The strip
solution was circulated at a rate of 3 cm 3 min-I , agiven portion of the circulating solution being trappedin a Teflon vessel put on a pure-Ge detector for measurement of ,-rays. Measurement of 5000 s duration
for the strip solution was automatically repeated, and80

the ,-ray spectra obtained were recorded on a disk.
The 0.5 mol dm- 3 NaHC0 3 solution was shown tobe better than distilled water as a strip solution giving higher rate of transport. Thereafter, the 0.5 mol
dm- 3 NaHC0 3 solution was used as a strip solution.
Only slight difference in the initial transport rates ofTc(VII) was observed for the feed solutions at pH 01.36 as shown in Fig. 1. However, the transport ofTc(VII) from the feed solution at pH 0 showed signs ofsaturation soon after the start of permeation. Transport of Tc(VII) from the feed solution at pH 0.54 increased gradually with time. In the permeation using
the feed solution at pH 0.74, the strip solution was
replaced by a fresh 0.5 mol dm- 3 NaHC0 3 solution
24 h after the start of transport. After replacement,
the transport yield was enhanced as shown in Fig. 1.
The transport behavior of Re(VII) is similar to that ofTc(VII) ; however, the amount of Re(VII) transported
at a given time is smaller than that of Tc(VII).

100~-------------------'

,

+++++
+ + +

-rrt-riXXXJ.jCOJ

o

10

20

30

40

50

Time/hFig. 1. Transport of Tc(VII) from feed solutions at pH
0- 1.36. pH 0 (.6) , pH 0.54 (0) , pH 0.74 (+) , and pH
1.36 (2). An arrow indicates replacement of the strip
solution with a fresh one in the permeation using thefeed solution at pH 0.74.

It is concluded that both Tc(VII) and Re(VII) can
be concentrated into a dil. NaHC0 3 solution from alarge volume of solution adjusted to pH 1 by means ofa supported liquid membrane impregnated with TBPdecalin. (Condensed from Radiochim. Acta, in press)

RIKEN Accel. Prog. Rep. 27 (1993)

Determination of Stability Constants of Lanthanide-Humate
Complexes with Multitracer Technique
Y. Minai, Y. Takahashi, M. Ishibashi,* S. Ambe, Y. Kobayashi, Y. Ohkubo, M. Iwamoto,
M. Yanokura, H. Maeda, N. Takematsu, F. Ambe, and T. Tominaga
Humic substances (humic acid, fulvic acid, andhumin) are a group of naturally-occurring organicpolyacids, having various functional groups which caninteract with metal cations in natural and artificiallymodified environments. Laboratory studies on stability of actinide(III) complexes of humic substances
have given relatively large values of stability constants
suggesting that their complexes of humic substances
can be dominant as their dissolved species in aqueous
environments. 1,2) Similarity in chemical properties between actinide(III) and lanthanide(III) elements suggests that considerable amounts of lanthanide com- ·plexes with humic substances are also formed in hydrosphere. Laboratory study of stability of lanthanidehumic substance complexes would provide key knowledge to elucidate the role of humic substance complexation in the geochemical behavior of lanthanides.
As was shown in a previous report ,3) it has been revealed that the multitracer technique is quite useful totake information on complexation between lanthanide
ions and humic substances. This report describes somepreliminary results on the determination of stability
constants of lanthanides with humic acid, using themultitracer technique.
A multitracer solution (3M HCI) was obtained fromthe gold foil target irradiated with 12C beam accelerated in RIKEN Ring Cyclotron. The preparation procedure for the multitracer solution was given
elsewhere. 4 ,S) After evaporation of the multitracer solution containing hydrochloric acid, 0.001 M perchloric
acid was added to make the multitracer solution used
for further experiments.
Solvent extraction with di(2-ethylhexyl)phosphate(DEHP) was used to determine the stability constantsof lanthanide-humates. 1,2) Free lanthanide ions in thehumic acid solutions containing the multitracer (1=0.1,
NaCI0 4 ) at pH 4- 6, which was maintained by pH
buffers, were extracted with DEHP in toluen. As noted
in previous reports,1,2) the observed distribution coefficient of each element is a function of the stability constant, the humic acid concentration, and thefree ion concentration. The last term of this function
was estimated by extrapolating the dependence of the*

distribution coefficient on pH and the DEHP concentration at pH 1- 2, where hydrolysis is negligible, in theabsence of the pH buffers.
The stability constants of the complexes of Eu, Gd,
Tm, Vb, and Lu with the humic acid were determined, assuming the formation of the 1:1 complex foreach lanthanide. The apparent stability constants ofthe Eu-humate log[j3(eq- 1)]determined at pH4.0, 4.6,
and 6.0 were approximately 8.5, 9.7, and 12.0, respectively. These values were identical with the reported
values determined by solvent extraction using a single tracer of europium. The stability constants of the
Gd-humate were also identical with those of the Euhumate, whereas the stability constants of Tm-, Yb-,
and Lu-humates (as 13) were approximately 10 times
higher than those of the Eu- and Gd-humates. Because of the small ionic radii of the heavier lanthanides(Tm, Yb, and Lu) relative to those of the middle lanthanides (Eu and Gd) , the electrostatic interaction
between their ions and the ligand molecule may bestronger in the heavier lanthanides than in the middle
lanthanides.
Recent studies on abundance patterns of lanthanides in oceanic sediments suggested that heavier
lanthanides migrate in the sediment column during
diagenesis. 6 ) Although there has been no report on direct evidence for the occurrence of lanthanide-humic
substance complexes in environments, higher stability of heavier lanthanide complexes with naturallyoccurring organic substances (including humic substances) may relate to the higher mobility of heavier
lanthanides reported.
References
1) Y. Minai et al.: Proc. 3rd. Int. Symp. Adv. Nucl. Energ.
Res., p. 229 (1991).
2) Y. Takahashi et al.: J. Radioanal. Nucl. Chern. Lett. , inpress.
3) Y. Minai et al.: RIKEN Accel. Prog. Rep., 26,89 (1992).
4) S. Ambe et al.: Chern. Lett., 1991, 149.
5) S. Ambe et al.: Anal. Sci., 7, Suppl. , p. 317 (1991).
6) Y. Minai et al.: Proc. Ocean Drilling Program, Sci. Results, 127/128, 719 (1992).

School of Science, University of Tokyo

81

RIKEN Accel. Prog. Rep. 27 (1993)

Utilization of Multitracer Solutions for Studies on the Ion
Exchange Behavior of a Strongly Acidic Resin NAFION
N. Aoki, H. Harakawa, Y. Saito, K. Kimura, S. Ambe, Y. Ohkubo, Y. Kobayashi,
M. Iwamoto, H. Maeda, M. Yanokura, and F. Ambe
Radioactive multitracer solutions, in a carrierand salt-free condition, prepared from silver 1,2) andgold 2- 4 ) foil irradiated with 135 MeV/nucleon 12C ionswere used for the titled studies in a NAFION-HF
system after being converted to a hydrofluoric acidsolution. The NAFION-501 resin, manufactured by
DuPont, is a perfluorinated polymer containing rv5
mmol g-l sulfonic acid groups. Because of the strong
acidity of the resin, a comparison of its exchange behavior with that of a common cation exchange resin
attracts much attention.
The resin, commercially available as a cylindricalshape of ca. 1 mm¢ x 3 mm, was crushed with a stamp
mill at liquid nitrogen temperature, passed through a
50-mesh screen, and used. Into a small polyethylene
bottle, 0.1 ml of the multitracer solution and 2.4 g of
the resin were introduced, and the acidity of the system was adjusted to 0.1,0.3,1,3, and 5 mol dm- 3 withhydrofluoric acid by making the volume of the solution
to 10 ml. The contents of the bottle were shaken vigorouslyat 25°C with an 8-shape mode shaker. Timeof the shaking was 16 hours for the silver-multitracer
and 75 hours for the gold-multitracer. After filtration,, -ray spectrometry was carried out for both phases.
The ,-ray spectra were analyzed on a FACOM M1800
computer.
The distribution ratios (D) of Na, Ga, Rb, Sr, Y,
Zr, Nb, Ru, Rh, and Pd were obtained from the silvermultitracer runs and those of Sc, Rb, Y, Ag, Ba, Ce,
Eu, Gd, Tb and Lu from the gold-multitracer runs.
The D's for Rb obtained from the silver and the gold
runs showed that the equilibrium was almost attainedby the 16 hours shaking. As shown in Fig. la, theslopes for alkali and alkaline earth metal ions in the
log-log plotting were approximately -1 and -2, respectively, which is characteristic of the ion exchange.
As for rare earth elements, the slope for Ce was approximately -3, whereas those for Y, Eu, Tb, and Lu
ranged from - 1 to - 2 (Fig. 1b). It seems likely that
there would be a relation between the slopes and ionicradii. D 's for noble metals in the hydrofluoric acid system remained rather constant with increasing acidity
and were not much different from those in a perchloric
acid system. 5 )

82

1000

(a)

6

N.

0

Rb

•

100

• Sr
0

0

0

10

0.1

0.1

10

0

1000

(b)

•

§
~

10

(:,

y

• Ce

8

100

o

•

.~~

•
'~
(,

0

Eu

~

Tb

t:.

Lu

!
~

0.1
0.1

10

Fig. 1. Relationship between D and acidity. (a) Na, Rb,
and Sf. (b) Y, Ce, Eu, Tb, and Lu.

References
1) S. Ambe, S. Y. Chen, Y. Ohkubo, Y. Kobayashi, M.
Iwamoto, M. Yanokura, and F. Ambe: RIKEN Accel.
Prog. Rep., 25, 95 (1991).
2) S. Ambe, S. Y. Chen, Y. Ohkubo, Y. Kobayashi, M.
Iwamoto, M. Yanokura, and F. Ambe: Anal. Sci., 7,
Suppl., p. 317 (1991).
3) S. Ambe, S. Y. Chen, Y. Ohkubo, Y. Kobayashi, M.
Iwamoto, and F. Ambe: RIKEN Accel. Prog. Rep.,
24, 73 (1990).
4) S. Ambe, S. Y. Chen, Y. Ohkubo, Y. Kobayashi, M.
Iwamoto, M. Yanokura, and F. Ambe: Chem. Lett.,
1991, 149.
5) T. Bamba, H. Harakawa, Y. Saito, K. Kimura, T. Yaita,
S. Shibata, S. Ambe, Y. Ohkubo, M. Iwamoto, Y.
Kobayashi, M. Yanokura, H. Maeda, and F. Ambe:
RIKEN Accel. Prog. Rep., 26, 88 (1992).

RIKEN Accel. Prog. Rep. 27 (1993)

Adsorption Behavior of Various Elements in Chloride Solutions on
Activated Carbon Fiber and Non-ionic Macro-reticular
Copolymer Using Multitracer
S. Shibata, K. Watari,* Y. Noda,* S. Ambe, Y. Ohkubo, M. Iwamoto,
Y. Kobayashi, M. Yanokura, H. Maeda, and F. Ambe
Activated carbon and non-ionic macro-reticular(MR) copolymers have been reported to be effective
adsorbents for a number of organic substances in aqueous solutions, but not enough attention has been paid
to the adsorption of inorganic substances. These adsorbents have particularly high distribution ratios (Kd)for tetrachloro complex anions of Fe(III), Ga(III) andAu (III) in HCI solutions above 6 mol·dm- 3 without
any other organic ligands. 1 ,2) Such peculiar adsorption
behavior has been observed in cation exchange resins,3)
too.
In the present work, the adsorption behavior of inorganic elements on Kynol ACF-1605-15 (novoloid-based
activated carbon fiber) and Amberlite XAD-7 (nonionic MRcopolymer) was studied in 0.01- 10 mol·dm- 3
solutions of HCI and LiCl. The multitracer was prepared by the irradiation of 135 MeV/nucleon 12C6+
onto Au or Ag foil. 4 )The retention of the elements was studied under
static conditions (batch method). The multitracer solution was shaken with the adsorbent for 2 hours, and ahalf of the supernatant (fraction s) and the remaining
half containing the adsorbent (fraction r) were divided.
The radioactivities of fractions sand r were measured
with a high-resolution gamma-ray spectrometer, andanalyzed with the BOB code5 ) on a SUN workstation.
The radioactive nuclides in the multi tracer were identified by the gamma-ray energies and half lives. Kd
was calculated byDD(ajACF-1605-15

Na Mg _.

TJ DDDDD

log[CI-)-' -, 0 ,AI,. SiPS CI

DDSD~DBDBDDDgDBBD
K~~nVD~~~M~~~~~~~Qg§uBD~~BBBD8D~~D~&V~~~~~~~~~~~~ThI

DB~[JBDDDBLJDDDDDD
Po
CS Ba

Hf Ta W Re Os Ir Pt Au Hg TI Pb Bi

EJDE1ts]DBBBDDBBE][~La Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Vb Lu

DO(b) XAD-7

~~

DDDDD
~~psa

DD~D~DQD~DDDDD~~D
K~~nVD~~~M~~~~~~~~D~B~~B~~~QDDD~~D~&Y~~~~~~~~~~~~ThI

Db]~g[;]DDD[d~DDDDDD
Cs Ba
Hf Ta W Re Os Ir Pt Au Hg TI Pb Bi Po
DDb]~DDDb]DDDb]bdQ
La Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Vb Lu

Fig. 1. Effect of CI- concentration in HCI (-) and Liel( .. -) on Kd values of elements for ACF-1605-15 (a) and
XAD-7 (b) .

from other targets.
Referenceswhere As and Ar are the peak areas of fractions sandr, respectively, and V and m denote the volume of asuspension (cm 3) and the weight of an adsorbent (g),respectively.
Figure 1 shows the adsorption profiles of 36 elements in log-log plotting of Kd against the concentration of CI-. An important feature of these
profiles is that the Kd of several elements increases
with increasing CI- concentration above 5 mol·dm- 3 .
The authors are now studying adsorption behavior of other elements using the multitracer prepared*

1) K. Watari, K. Imai, S. Shibata, and M. Miura: J. At.
Energy Soc., Japan, 26, 384 (1984).
2) S. Shibata, K. Watari, and K. Kaneko: Radioisotopes,
39, 26 (1990).
3) F. Nelson, T. Murase, and K. A. Kraus: J. Chromatog.,
13, 503 (1964).
4) S. Ambe, S. Y. Chen, Y. Ohkubo, Y . Kobayashi, M.
Iwamoto, M. Yanokura, and F. Ambe: Anal. Sci., 7,
Suppl., 317 (1991).
5) H. Baba, H. Okashita, S. Baba, T. Suzuki, H. Umezawa,and H. Natsume: J. Nucl. Sci. Technol., 8, 1227 (1972).

Natl. Inst. Radiol. Sci.

83

RIKEN Accel. Prog. Rep. 27 (1993)

Study of the Solvent Extraction of Various Elements with
Diphosphine Dioxide (DPDO) by Use of the Multitracer
T. Yaita, S. Tachimori ,* S. Ambe, M. Iwamoto, Y. Kobayashi ,H. Maeda, Y. Ohkubo, M. Yanokura, and F. Ambe
Diphosphine dioxides (DPDOs; Fig. 1) are one of
neutral bidentates and show the highest extractability
in these organophosphorous compounds for trivalentlanthanide and actinide elements from nitric acid solutions.

Fig. 1. Diphosphine dioxides R 1 , R2
(this work).

p-Tol, X=CH 2

However, distribution coefficients of DPDO have notbeen obtained for most of elements except several lanthanide and actinide elements. Therefore, from thestandpoint of the separation of lanthanide and actinide
elements from the others, it is interest ing and important to clarify the extraction properties of DPDO andto compare them with those of other bidentate extractants. In this work, the distribution coefficients (Kd )of DPDO for various elements were determined by using the multitracer.
Recently, a large number of radioactive nuclides havebeen produced as the multitracer by the high-energy
heavy-ion irradiation on several targets in the RIKEN
Ring Cyclotron. 1 ,2) The multitracer technique makes
it possible to determine Kd values of various elements
under the same condition, and has greater advantage
than the single tracer technique in solvent extraction
experiments.
Multitracer solutions were obtained from the Au targets irradiated with 12C beam accelerated by RIKEN
Ring Cyclotron. The irradiated target was dissolved inaqua regia. This solution was evaporated to dryness.
After this residue was dissolved in 3 mol dm- 3 HCI,
Au was removed from the solution with diethyl ether
solvent extraction and the aqueous phase was dried up
again. Finally, the residue containing the multitracer
was dissolved in 1- 12 mol dm- 3 HN0 3 .
The nitric acid solution containing the multi tracer
was shaken with a 0.02 M DPDO-CHCb solution for*
84

Japan Atomic Energy Res. Inst .

20 min. , and separated again by centrifugation for 10
min. Then, the radioactivity of organic and aqueous
phases was measured. The distribution coefficient wascalculated from the following formula:where [Mlorg and [Mlaq denote the radioactivity of
nuclides in the organic and aqueous aliquots, respectively. Figure 2 shows the dependence of Kd values
for various elements on the nitric acid concentration.
From this figure , it is clear that the trivalent elements(Y, Tm, In) can be separated from noble metal elements (Ru, Rh, Ir, Au) and the alkaline earth element(Ba). Furthermore, the variation patterns were classified into three categories: (1) two peaks with the
maximum about 4 M HN0 3 and the minimum in therange of 8- 10 M HN0 3 , (2) no acidity dependence and(3) simple increase of Kd with HN0 3 concentration.

Fig. 2. The nitric acid dependence of Kd values for various
elements.

References
1) S. Ambe, S. Y. Chen, Y . Ohkubo, Y . Kobayashi , M.
Iwamoto, M. Yanokura, and F. Ambe: Chern. Lett. ,1991 , 149.
2) S. Ambe, S. Y. Chen, Y. Ohkubo, Y . Kobayashi , M.
Iwamoto, M. Yanokura, and F. Ambe: Anal. Sci. , 7 ,Suppl., p. 317 (1992).

RIKEN Accel. Prog. Rep. 27 (1993)

Yield Distributions of Hf Isotopes from the Reactionsof Heavy Ions on W Target
W. Li, S. Ambe, Y. Ohkubo, M. Iwamoto, Y. Kobayashi, H. Maeda, and F. Ambe
Recently, the multinucleon transfer reaction has
achieved great success in production of new neutronrich nuclides above the classical fission product region(A > 170). In order to search for even more neutronrich nuclides and to study decay properties of suchexotic nuclei in this mass region, it is instructive to examine the general evolution of the yield distribution of
the target residues produced from heavy ion reactions.
For this purpose, we have carried out a series of yieldmeasurements for Hf isotopes produced from the reactions of natural W targets with 135 MeV jnucleon 12C,
80 MeV jnucleon 16 0, 40 MeV jnucleon 40 Ar, and 10.5
MeV jnucleon 84Kr ions. In this report, we give theyield distribution of Hf isotopes produced from the 10.5
Me V j nucleon 84 Kr + W reaction. The results are compared with those from the 135 MeV jnucleon 12C + W
reaction.
Natural W metal foil (47 mgjcm 2 ) was irradiatedfor 20 min by 10.5 MeV jnucleon 84Kr ions deliveredfrom RIKEN Ring Cyclotron. After the end of irradiation, the target was immediately transferred to the hotlaboratory by Falling Ball Irradiation System. The W
foil was dissolved in a mixture of concentrated HF and
HN0 3 , containing 10 mg Hf carrier. An Sm3 + solution
was added to remove the radioactive rare earth nuclides by co-precipitation with SmF 3 . Hf was then precipitated in the form of BaHfF 6 by adding a Ba2+ solution. After the precipitate was dissolved in HN0 3 saturated with H3 B0 3 , Hf was extracted from an about
10 mol dm- 3 HN0 3 solution containing 1% H 20 2 to a
25% HDEHP (di(2-ethylhexyl)phosphate)-toluene solution. A 1 mol dm- 3 HF-1 mol dm- 3 HN0 3 solution was used for back-extraction of Hf from the organic phase. Finally, Hf was precipitated once again
as BaHfF 6, and was subjected to 1'-ray spectroscopy.
The chemical separation took only about 8 min and 1'ray counting began 11 min after the end of irradiation.
Chemical yield of Hf was about 80% as determined ina cold experiment.
In this experiment, the cumulative yields were determined for 10 Hf isotopes ranging from 166 to 183
in mass number. The yield dependence on the mass
number of the Hf isotopes is shown in Fig. 1. Although neutron-deficient nuclides are dominant among
the radioactive Hf isotopes, neutron-rich Hf nuclides
were also produced with non-negligible cross sections.

1000'c::J 100
.ri

ia

c-o

A

'u
Q)

CIl
CIl

~

o

10

&

T
1
160

1

l
164168172

176180184

188

Mass number A

Fig. 1. The yield distribution of Hf isotopes for the reaction of a natural W target with 10.5 MeV/nucleon 84Kr
ions. The arrows show stable isotopes with no isomers.

When compared with similar measurements on the reaction of a W target with 135 MeV jnucleon 12C ions(see Fig. 2), it is obvious that the low-energy 8 4Kr ions
are more favorable than the intermediate energy 12C
ions for efficient production of neutron-rich exotic nuclides relative to neutron-deficient nuclides resulting in
improvement of S jN ratio in detection of the former.
Data analysis is still in progress.

1000

100

:0E

c-o

U 10
Q)

CIl
CIl

<11

o

o
~

.1
160

164

168

172

176

180

184

188

Mass number A

Fig. 2. The yield distribution of Hf isotopes for the reaction of a natural W target with 135 MeV/nucleon 12C
ions. The arrows show stable isotopes with no isomers.

85

RIKEN Accel. Prog. Rep. 27 (1993)

Study on the Nuclear Reactions of 93Nb, 181Ta, and 197 Au
Induced by Secondary Neutrons in 40 MeV/nucleon
40 Ar Ion Collisions
W. Li, Y. Ohkubo, S. Ambe, Y. Kobayashi, M. Iwamoto, H. Maeda, and F. Ambe
Shikata et al. and Nakajima et al. reported somemeasurements on the reactions induced by secondary
neutrons produced by irradiation of a thick iron target with 135 MeV/nucleon 14N ions. 1,2) In their experiments, emphasis was placed only on the (n, xn)
reactions, where x is 2- 5. It is necessary to carry out
a full measurement for all of the reaction products inorder to understand the secondary-neutron-induced reactions. As a first general survey, the present report
gives the experimental results from study on nuclear
reactions of 93Nb, 181Ta, and 197 Au targets with thesecondary neutrons produced by irradiation of a thickstainless steel target with 40 MeV/nucleon 40 Ar ions.
The experiments were performed on the RIKEN
Ring Cyclotron. Forty MeV/nucleon 40 Ar ions were
stopped in a stainless steel Faraday cup with a thickness of 1.2 cm after traversing primary targets consisting mainly of 0.1 mm thick gold foil for a different experiment. A secondary target assembly used forneutron irradiation was placed immediately behind the
Faraday cup. The target assembly consisted of 27 AI,
93Nb, 181Ta, and 197 Au foil. The irradiation lasted
for about 23 h (with several interruptions). Following
the irradiation, the secondary targets were analyzed
by direct I-ray spectroscopy for 4-5 weeks. Nuclidic
assignment and yield calculation were done by conventional nuclear chemical techniques.
In this work, the yields for the reaction products
were determined relative to that of 24Na produced
from the reference reaction of 27 AI(n , o:) 24 Na. The
mass yield distributions obtained from the experimental data are shown in Fig. 1 as a function of mass loss!:1A from the target for the reactions of 93Nb, 18 1Ta,
and 197 Au, respectively.
The mass yield distributions, as seen from Fig. 1,
are approximately parallel with each other. The slopes
were calculated to be 2.30 ± 0.27 u- 1, 2.29 ± 0.26 u-l,
and 2.48 ± 0.18 u- 1 (u: mass unit) for the reactionsof 93Nb, 181Ta, and 197 Au targets, respectively. These
values are in good agreement within the experimental errors, indicating that the slope of the mass yield
distribution is independent of the target species forthe secondary-neutron induced reactions. The lightest
products were found to be 86yg and 86Zr in the acti-

86

1000000
100000
10000

~

1000

~

';;'

100

...
-.;::

10

Q)

ell

~
~

.1
.01

-7

-6

-5

-4

-3

-2

-1

0

Mass loss I:l.A

Fig. 1. The mass yield distributions as a function of massloss ~A from the target for the reactions of 93Nb, l81Ta,
and 197 Au with the secondary neutrons produced fromthe irradiation of a thick stainless steel target with 40
Me V / nucleon 40 Ar ions. The solid lines are the linear
regressions of the data.

vated 93Nb targets, which resulted from removal of 8
nucleons from the composite system of a target nucleus
and a neutron. The separation energy of a neutron isabout 8 Me V for the nuclides involved in this work andthe kinetic energy of the neutrons emitted from thecomposite system is about 2 Me V on average. Thus,
we can draw the conclusion that a significant fractionof the secondary neutrons had an energy larger than
70 MeV, which is much larger than the incident energy per nucleon of the 40 Ar ions. The estimation is
supported by the neutron inclusive measurements withthe time-of-flight method on the 14N + Ag reaction at
35 MeV /nucleon. 3)
References
1) T. Shikata et al.: RIKEN Accel. Prog. Rep., 25, 250(1991).
2) S. Nakajima et al.: ibid., 26, 183 (1992).
3) H. R. Schelin et al.: Phys. Rev., C39, 1827 (1989).

RIKEN Accel. Prog. Rep. 27 (1993)

Limiting Behavior of the Recoil Velocities
in the Heavy-Ion Reactions
H. Baba, M. FUrukawa, Y. Ohkubo, T. Saito, A. Shinohara,
K. Takesako, S. Watanabe, and A. Yokoyama
Intermediate and high energy heavy-ion reactions
mostly involve fragmentation of target nuclei. It
has been demonstrated that the slope against A ofthe mass-yield curve for target-fragmentation products
reaches a limiting value at projectile energies around 2
GeV, irrespective of light or heavy-ion projectiles. We
found that the limiting fragmentation is manifested in
the fragmentation of lanthanoid target nuclei inducedby heavy ions with energies above 1 GeV. 1) Here we
discuss the limiting behavior of the recoil velocities of
the reaction products.
The experiments were carried out at the E3b beamcourse in RIKEN Ring Cyclotron. Sheets of Pr andHo foil together with Al catchers were bombarded withheavy-ion beams as listed in Table 1. The irradiatedfoil was separately subjected to off-beam gamma-ray
spectrometry with Ge detectors.
Table 1. The mean values of the recoil velocities of thereaction products.
Projectile
15N
HN
40 Ar
40 Ar

Energy(GeV)

Target

1.05
1.89
2.36
3.80

165Ho
165 Ho
H1Pr
141 Pr(,811)(x10- 2 )1.25±0.09
1.12±0.10
1.38±0.06
1.18±0.12

The mean projected recoil ranges are obtained as the
product of the thickness of the target and the ratio of
the radioactivities detected both in the target and theforward cather foil. The recoil velocities of the productnuclides, /311' were deduced from their recoil ranges byusing the range-velocity relationship. It is seen in all
systems that the recoil velocity inceases slightly as the
product mass number decreases. The mean values of(311 in each reaction system are summarized in Table
1. The mean recoil velocities are practically the same
within the error for the systems of different targetprojectile combinations.
The results of the radiochemical experiments on target fragmentation are informative to examine the ac-tual kinematics of the two-step process. This model
has been successful in describing the fragmentation
process. The properties of the recoil velocities can beunderstood on the basis of this model. 2) The recoil velocity of the excited target nucleus MF is related tothe excitation energy E*. The product MFE* is then
expected to give a particular limiting value in a highenergy region. This is demonstrated in Fig. 1, together
with the present results indicating that a transient typeof the limiting behavior of the recoil velocity appears
at the energy where the mass distribution attains thelimiting behavior. Both may be ascribed to a phasetransition of the collective motion of nucleons.

:>

J; 30

*~ 20
~

~

10

o100

~

t

~

101

102

ELAB

(GeV)

103

Fig. 1. The product MFE* as a function of the projectile energy. Circles represent the data in this work andtriangles those given in Ref. 2. Open and solid symbols correspond to the systems with light and heavy
projectiles, respectively.

References
1) K. Takesako, T. Saito, H. Kusawake, A . Yokoyama, H.
Baba, Y. Ohkubo, A. Shinohara, and M. Furukawa:
RIKEN Accel. Prog. Rep. , 26, 91 (1992) .
2) E. M. Friedlander and H. H. Heckman: in Treatise on

Heavy-Ion Science, edited by D. A. Bromley, Plenum,
New York, 4 , 403 (1985).

87

RIKEN Accel. Prog. Rep. 27 (1993)

Dependence of Mass Transfer in the Heavy Ion Reaction
on the Mass Asymmetry at Entrance Channel
M. Kiriu, A. Yokoyama, K. Takesako,* S. Watanabe, N. Takahashi,
T. Saito, H. Baba, and Y. Ohkubo
Deep inelastic reaction is an important process inthe heavy-ion-induced reaction especially for the energy region below 100 MeV ju. This is a dissipative
process accompanying a large amount of kinetic energy loss and transfer of several dozens of nucleonsat most. These features are explained by the modelof formation and disintegration of a dinuclear system.
The results of calculation for the deep inelastic process
are, however, very much affected by the reaction time,
namely, the life time of the dinuclear system. We measured the mass distribution of 51 V with 136Xe ions andthat of 175Lu with 12C ions to obtain information on
the dinuclear life time. The results were subjected tothe analysis based on a diffusion mode1 1) together withother data of nearly the same composite system withdifferent mass asymmetry at the entrance channel inorder to compare the feature of the mass distributions
and deduce a systematics of the reaction time.
A sheet of vanadium foil with a thickness of 8.47
mgjcm 2 was bombarded with a 136Xe beam (8.5
MeV ju) at the E3b beam course of RIKEN Ring Cyclotron. The Xe ions lose their kinetic energy down
to 7.1 MeV at the target center. Two sheets of Al
catcher foil (5.67 mgjcm 2 thick) were placed downstream of the target. Irradiation time of the stack was
about 90 min. The carbon ion beam for bombarding
175Lu targets was obtained from the AVF cyclotron of
Research Center for Nuclear Physics, Osaka University. The target foil was sandwiched with catcher foil
and irradiated with 12C ions of 110MeV at the target
center for 142 minutes. Identification and yield determination of the product nuclides were carried out by
off-beam ,-ray spectrometry.
According to the prescription of the diffusion model,
the relation between the reaction time of DIT and thedispersion of mass distribution ((JDIT) can be describedas(1)
if dependence of evolution of the dinuclear system on
the angular momentum is neglected for simplification.
Moreover by using a calculated diffusion coefficientD~ which applies very well to a large quantity of ex-*
88Fac. Sci., Osaka University

perimental data, the reaction time is deduced fromthe mass distribution. Obtained time is plotted inFig. 1 versus mass asymmetry at entrance channel together with data obtained from references. 2 ) The figure
demonstrates that the reaction time is independent ofmass asymmetry except for a very asymmetric case of
the present study. This consequence is clearly different from the linearly increasing reaction time deduced
from the ejectile angular distribution by Agarwa1 3) as
indicated in Fig. 1. This implies that the apparent
reaction time presently deduced involves the disper. sion due to mass flow and fluctuation in the dinuclear
system and therefore it is tenable to supply some information on the dynamics of mass flow in the dinuclear
system. We like to point out that the presently deduced apparent reaction time appears to show clearcut dependence on the direction of mass flow in the
dinuclear system.

tt
W 220.'---<""--'----'.--'-:O.L.,-'--'--L-'-:O.L.2-'----'---'-L-OL..}-'----'---'-l.-..J. 4
O

AL I ( AL +AHl

Fig. 1. Reaction time of deep inelastic process versus
mass asymmetry at entrance channel. Closed and open
circles represent the data from the present study andthose from references , respectively.

References
1) S. Ayik et al.: Z. Phys. A , 277, 299 (1976); S. Ayik
et al.: ibid. , 279, 145 (1976) ; G. Wolschin and W.
Norenberg: ibid. , 284, 209 (1978).
2) H. Kusawake: Osaka Univ. Master Thesis, p. 13 (1990);
J. V. Kratz et al.: Phys. Rev. , C13, 2347 (1976) ; J.
V. Kratz et al.: Phys. Rev. Lett. , 33, 502 (1976); R. J.
Otto et al.: ibid. , 36, 135 (1976).
3) S. Agarwal: Z. Phys. A, 297, 41(1980) .

RIKEN Accel. Prog. Rep. 27 (1993)

Competition between Fission and Spallation in the Reaction
Induced by Intermediate Energy Heavy Ions
J. Kurachi, E. Taniguchi, A. Shinohara, M. Furukawa, S. Kojima, Y. Ohkubo,
F. Ambe, K. Takesako, A. Yokoyama, T. Saito, H. Baba, and S. Shibata
Nuclear reactions induced by intermediate energy
heavy ions have been extensively investigated. But
heavy ion induced fission has not been clearly understood. We measured the product yields and linear momentum transfer in the interaction of gold with intermediate energy heavy ions to study the projectile
dependence of the nuclear reactions including fission.
The targets were irradiated with heavy-ion beams
at the falling ball irradiation facility!) installed at theE3b course of the RIKEN Ring Cyclotron. The irradiation conditions are shown in Table 1. The target
stack consisted of gold foil (20-48 mg/cm 2 thick) surrounded by Mylar, Kapton, carbon or aluminum catchers. After irradiation, the targets and the catcher foil
were assayed by means of non-destructive ,-ray spectrometry. Formation cross sections were determinedfrom measured disintegration rate of the products inthe whole target stack. Mass yield distributions werededuced from the obtained formation cross sections.
Linear momentum transfer and isotropic momentum
components were calculated from the measured recoil
ranges, 2W(F + B), and the forward-to-backward ratios, F /B, by means of a two step vector model. 2) Here,. W is the target thickness, F and B are activity ratios ofgiven products in the forward and backward catchers
to the total activity, respectively.

teraction is the fusion of target nucleus and the part ofprojectile that gives measured linear momentum transfer to the product.
The angular momenta decrease with increasing incident energy and seem to be constant at higher energies, as shown in Fig. 1. The variation of fission crosssection is shown in Fig. 2. The fission cross section
decreases with increasing incident energy per nucleon:
its variation is similar to that of angular momentum.
100

E

at:
CI.l

E

0

Projectile

Irradiation
time (sec)

Total flux
(particles)

50

-

:E...

o

-

t

o

«l

"3

CIC
t:

<

0

o

I

I

~

100

150

Projectile Energy (MeV/nucleon)

Fig. 1. Dependence of angular momentum imparted toexcited nucleus on projectile energy. Symbols indicate
different incident particles; 0: 14 , 15 N, e: 40 Ar.

Table 1. Irradiation conditions.
Energy(MeV/u)-,6

2.0 ,----- - - --- - - --,

Target thickness(mg/cm2)

14N

35

3618

4.76xl014

48 .3

15N

70

5730

8.95xlO13

43.3

14N

135

8960

1.47xl0 14

43.3

4OAr

30

2400

1.05x lO 14

20.6

4oAr

38

3547

2.28xlO13

37.6

4OAr

59

4056

3.06xlOJ3

43.5

4OAr

95

4386

2.28xlOJ3

45 .0

to
0.0

' - ----''-------'1_---'-_ _.L...-1_.L....----'oSpallation, fission and nucleon transfer reaction
products were observed. The mass distribution of fission products was obtained by subtracting spallation
component from mass yield in the range of A = 55130. The spallation component was extrapolated fromthe mass yields in the range of A = 135- 175. The fission cross sections were estimated from the mass distribution of fission products assuming that its shape isGaussian. The angular momentum imparted to the excited nucleus was estimated, assuming that initial in-

~

100

150

Projecti Ie Energy (Me V /nucleon)

Fig. 2. Dependence of fission cross section on projectile
energy. Symbols indicate different incident particles; 0:
14, 15 N, e: 40 Ar.

References
1) F. Ambe et al.: Chern. Lett., 1991, 49.
2) L. Winsberg: Nucl. Instrum. Methods, 150,465 (1978).

89

RIKEN Accel. Prog. Rep. 27 (1993)

Time-Differential Perturbed-Angular-Correlation (TDPAC) of,-Rays of 99Ru in YBa2Cu307-x Using 99Rh as a Source Nuclide
Y. Ohkubo, Y. Kobayashi , K. Harasawa, S. Ambe, T . Okada, S. Shibata, K. Asai , and F. Ambe
In a previous experiment 1) we first prepared
YBa2Cu307-x (x ~ 0.2) containing 99Rh, which decays to 99Ru. All heating processes were done in flowing oxygen. Then, we prepared YBa2Cu307- x (99Rh)(x ~ 1) by heating the YBa2Cu307-x (99Rh) (x ~ 0.2)
sample at 760°C over 6 h, holding it at that temperature for 1 h , and cooling to room temperature over 16
h all the while under reduced pressure of about 3 Pa.
By measuring TDPAC spectra for the 3/2+ level of
99Ru in the two samples, we obtained results indicating that Rh ions occupy the Cu-l site exclusively. We
considered the reason for the result to be as follows:
Rh ions prefer + 3 valence. Since we first prepared
YBa2Cu307- x (99Rh) (x ~ 0.2) in oxygen and the average valence of the Cu ions at the Cu-l site was close
to +3 while that of the Cu-2 site was +2 , Rh ions occupied the Cu-l site. The temperature of 760°C needed
to prepare YBa2Cu307-x (99Rh) (x ~ 1) was not highenough for Rh ions at the Cu-l site to move to theCu-2 site.
In the present experiment we heated YBa2Cu307-x(99Rh) (x ~ 0.2) in flowing nitrogen at several temperatures to attempt to prepare YBa2Cu30 7-x (99Rh)(x ~ 1) following the heating process 2) employed bySmith, Taylor, and Oesterreicher, and then measured
the TDPAC spectra of 99Ru in those samples to see
whether Rh ions at the Cu-l site move to the Cu-2
site.
About 97% enriched 99Ru was irradiated with 13MeV protons available from the INS-SF cyclotron. A
carrier-free solution containing 99Rh3+ was obtained
from the irradiated ruthenium target by radiochemical
separation. CuO powder was added to the solution inorder to let it adsorb 99Rh3+. An essentially identical
heating process to that used in Ref. 1 was employed toprepare YBa2Cu307-x (99Rh) (x ~ 0.2). This material
was heated in nitrogen at 770 ° C for 2 days, quenched
quickly to room temperature and subjected to TDPAC
measurement. Similar processes were followed at 820,
870, and 920°C on the same sample.
Measurements of the TDPAC spectra of 99Ru in thesample heated in nitrogen at 820°C were made at
10, 293, and 573 K. Those for the samples heated atother temperatures were made only at 293 K. Figure l(a) shows the frequency spectra at 293 K of
YBaCuO(99Ru) prepared at 770, 820, 870, and 920°C. Here, we use the notation YBaCuO, consideringthat a part ofYBa2Cu307-x possibly decomposed into
Y2BaCuOs during the heating in nitrogen. Figure l(b)

90

(a)

healed in N2 al 770 0 e (b)measured al 293 K
3

·s::I
.Q

r..
~

~
.~ 3

healed in N2 at 870 0 e
measured at 293 K

:s
~

2
I

heated in
vacuumal
7600 emeasuredat 293 Ko o~---:---7"""'"""=~
Frequency (108 rad/s)

Frequency (l08 rad/s)

Fig. 1. (a) Frequency spectra at 293 K of 99Ru in YBaCuO
prepared by heating YBa2 Cu 3 0 7- x (99Rh) (x;s 0.2) innitrogen. (b) Frequency spectra at 10, 293, and 573 K
of 99Ru in YBaCuO prepared in nitrogen at 820 °C. The
frequency spectrum at 293 K of YBa2 Cu 3 07-x (99Ru)(x ~ 1) prepared in the previous experiment l ) is also
shown in the bottom for comparison.

shows those of the sample prepared at 820 ° C and measured at 10, 293, and 573 K. The frequency spectrumat 293 K of YBa2Cu307-x (99Ru) (x ~ 1) preparedin the previous experiment 1 ) is also shown in Fig. l(b)for comparison. A new peak indicated with an arrowappears in the measurement at 293 K for the samples
prepared at 820, 870, and 920°C, but not for the sample prepared at 770 °C, as seen in Fig. l(a). We canobserve from Fig. l(b) that this peak is considerably
reduced at 573 K. It is reported that there is antiferromagnetic ordering with TN = 420 K at the Cu-2 siteof YBa2Cu307-x (x ~ 1). We are thus tempted to assign this peak to 99Ru which moved to the Cu-2 site.
However, we are not convinced of it yet. The peakassignments are under consideration.
References
1) Y. Ohkubo, Y. Kobayashi, K. Harasawa, S. Ambe, T.
Okada, K. Asai , S. Shibata, S. Takeno, and F. Ambe:
RIKEN Accel. Prog. Rep., 26 , 95 (1992) .
2) M. G . Smith, R. D. Taylor, and H. Oesterreicher: Phys.
Rev. B , 42 , 4202 (1990).

RIKEN Accel. Prog. Rep. 27 (1993)

Slow Positron Beam Production Using AVF Cyclotron
Y. Itoh, Y. Ito, I. Kanazawa, N. Ohshima, Y. Yamamoto, N. Nakanishi, A. Goto, and M. Kase
Experiments to produce an intense slow positron
beam have been started from 1993. The method is to
produce short lifetime {3+ -decay radioisotopes by nuclear reactions, and then to stop the emitted high energy positrons in a moderator having a negative work
function for positron. Since a fraction of the stopped
positrons are re-emitted from the surface with verysmall emittance, they are collected and accelerated toa desired energy. The technique of using the negative
work function moderator has become a common practice, and usually long lifetime radioisotope (22Na) orelectron linacs are used as the sources of fast positrons.
However the intensity of the slow positrons obtained
from the long lifetime radioisotopes is limited to lessthan 105 e+ Is. Intense slow positron beams can beobtained when electron linacs are used, but the pulsed
nature of the beam (several ms) sets limitations to theapplicability for practical purposes. Intense and constant wave slow positron beams are desirable for many
experiments, and for this purpose the use of short lifetime {3+ -decay radioisotopes produced by nuclear reactions is a promising method because the yield of isotope production is high. Due to the short lifetimesof the positron emitters, slow positron beams must be
produced on-line with the operation of the accelerator.
Reactions as llB(p ,n)llC , 14N(p,a)llC, 19F(p,n)19Ne,
23Na(p,n)23Mg, 12C(d,n)13N, ... etc. are considered
to be efficient to produce intense positron emitters,
and boron nitride, NaF, and carbon film are the candidate target materials. But the choice of the reactions and target materials is not straightforward since
the yield and the characteristics (e.g. emittance) of theslow positron beam depend not only on the nuclear reactions but also on various factors like the distributionof the positron emitters in the target, emission of fast
positrons from the target, geometry of the moderator
with respect to the target, and so on. The first step ofour experiments is to compare various target materials. For this purpose we have constructed a temporary
target chamber and a slow positron beam guide (Fig.
1). A thin film or plate of target material is mounted
on a water cooled holder at an angle of 30 degrees tothe incident proton beam. As the moderator a tungsten film 10 J.tm thick and well annealed at about 2000
°C is placed 5 mm apart from the target, and the slow
positrons re-emitted from the moderator are accelerated to 50-500 eV and are guided through the solenoidtransport tube. The yield and the beam profile of theslow positrons are measured by MCPA (micro channel
plate array).

slow e+'i',4t
ion beam
II

¢

II
II
II

~:.....-..

Helmholz
coil

~

slit

II
II

"

I I

II

"

»

~~::ster<

"

) I

,11

target holder

moderator

Fig. 1. Schematic diagram of slow positron beam production .

91

RIKEN Accel. Prog. Rep. 27 (1993)

Positronium Formation and Annihilation in Porous Silicon
Y. Itoh, H. Murakami, and A. Kinoshita*
Porous silicon is an important electronic material
in the current fabrication technology and its visible
photoluminescence has attracted strong attention on
development of a photo-electronic device. The physical and chemical properties of porous silicon are dominantly controlled by the surface state of a porous layer.
Various techniques are utilized to study the surface
states. Positron annihilation spectroscopy is also a
powerful tool since it is very sensitive to holes or pores.
We have measured the positron annihilation in
porous silicon, and reported that two lifetime components are very long and the Doppler broadened annihilation radiation is sharpened by magnetic field. 1 ) It
is concluded that the efficient yield of positronium isformed in the porous silicon. In a present study, we
report the results of temperature dependence of thepositronium yield and lifetime in porous silicon, and of
the effect of gas adsorption on the positronium states.
Figure 1 shows that the longest lifetime compo-

5045r-----------------------~

•

..

I

•

35

50

100

150

200

250

300

Temperature I K

Fig. 1. Temperature dependence of the longest lifetime
component.

*
92

Physics Dept., Tokyo Denki University

nent is about 34 ns at 300 K , which increases to 45
ns as the temperature decreases to about 100 K andthen levels off at about 45 ns from 100 K to about
10 K. The second lifetime component of about 0.55
ns is almost constant in the temperature range of 300
K to 10 K. The longest lifetime and the second one
are considered to correspond to the positronium lifetime in free state in the pores and that trapped on
the pore surfaces. The intensity of the longest lifetime
component decreases while that of the 0.55 ns component increases with the temperature decrease to 100
K and both intensities level off below 100 K. It follows that the surface trapped positronium of 0.55 ns
increases and the free positronium of the longest lifetime decreases with the temperature decrease. Thechanges of both intensities originate from the thermal
activation of positronium emission from the pore surfaces. The adsorption effect of residual gas on the poresurface has also to be taken into account in order toexplain the lifetime and intensity saturation below 100
K. Therefore, the effect of gas on the positron annihilation in the porous silicon was examined. Oxygen gas
causes a drastic decrease in the intensity and lifetimeof the longest lifetime component at 300 K. These decreases of lifetime and intensity have arisen from thespin conversion of ortho-positronium by an unpaired
electron of oxygen. We are making the experiments on
the temperature dependence of lifetime and intensity
in porous silicon under a designated gas atmospheresuch as oxygen, nitrogen and others. The saturation
effect shall be clearly understood from the results on
the gas adsorption on the pore surfaces.
With the aid of positron annihilation spectroscopy,
it is possible to make the surface state of porous silicon
clear and elucidate the photoluminescence mechanism.
References
1) Y. Itoh, H. Murakami, and A. Kinoshita: Appl. Phys.
Lett., 63(20), 1 (1993).

RIKEN Accel. Prog. Rep. 27 (1993)

Heavy Ion Beam Analysis for H-D Isotope
Exchange in Glass Surface Layers
T. Kobayashi, T. Nozaki, M. Aratani, and M. Yanokura
Cations in surface layers of silicate glass are known
to be replaced by hydrogen in hot water, and the hydrogen can be back-replaced by cations or submitted to H-D isotope exchange. We thought that thedeuterated glass, made by dipping in hot D 2 0 fora week, could be used for time-integration monitoring of vapour pressure and cation contents of soil water. Various silicate glass plates were surveyed for the
rates of the above three reactions under various conditions. Saturated solutions of highly soluble salts andhydroxide-oxide mixtures were used to give well reproducible vapour pressures. The sample surface wasanalyzed by the simultaneous measurement of heavy
ion ERDA (Elastic Recoil Detection Analysis), RFS(Rutherford Forward Scattering) and RBS (Rutherford Back Scattering) under almost the same conditions as in our previous measurements. 1)
The hydrogenation in harder glass proceeded more
slowly but to a larger depths (mostly over 3 /-Lm) thanin softer glass (often under 1.5 /-Lm) in prolonged dipping in hot water (several days, 130- 180 °C). The hydrogenated layers of soft glass were dissolved graduallyin hot water to be detected by the colorimetry of silica; this dissolution can be the cause of poorer reproducibility observed for softer glass in all the three reactions. Figure 1 shows the ERDA spectrum of the Pyrex
glass deuterated and exposed to moisture. Under measurement conditions giving a nearly rectangular spec-

trum for homogeneously distributed deuterium, as inour present measurement, K = (R - Ro)/(4 + R) is areasonable and convenient measure of the degree of Dby-H replacement , where Ro and R are the ratios of
ROI A value to ROI B value for the deuterated glass
without and after a moisture exposure, respectively.
Figure 2 shows the K values for deuterated Pyrex glass
chips heated with La(OH)J-La203 in sealed tubes. At
250°C, a considerable decrease of total hydrogen in
the glass was also observed at the beginning, and thiscan be related with the lower exchange rates in the
successive stages. The glass giving Fig.l is one of thesamples of our preliminary field experiment, in which
deuterated glass chips were buried.in a desert land for5 months at depths from 10 to 165 cm; the K values
found were from 1.66 to 1.77. We intend to prepare a
set for moisture monitoring, utilizing micro-pore membranes in conjunction with the deuterated glass.

g* 0.2
~

01)

=
~

-=><
(J

w

=
Q

2S0'C

I

f

D. l

10
Heating Time (h)20Fig. 2. Degree of D-by-H exchange in the Pyrex glass
heated with La(OH)J-La203. *See text.

~ROIA~~ROIB~

Fig. 1. An ERDA spectrum of the Pyrex glass deuterated and exposed to moisture. (Ordinate: Counts perchannel in linear scale)

References
1) H. Nagai, S. Hayashi, M. Aratani, T. Nozaki, M.
Yanokura, I. Kohno, O. Kuboi , and Y. Yatsurugi: Nucl.
Instrum. Methods Phys. Res., B28, 59(1987).

934. Radiation Chemistry and Radiation Biology

RIKEN Accel. Prog. Rep. 27 (1993)

Time and Depth Resolved Dynamics of Excited States in
Ion Track in Condensed Matter
K. Kimura, Y. Sahara, K. Yokoo, and T. Shiba(1) Dynamics of core excitons produced in ion irradiated BaF 2
Ion irradiated BaF 2 exhibits two kinds of luminescence with peak wavelengths at 220 and 310 nm, which
can be observed also by vacuum-ultra-violet photoirradiation and electron irradiation with low LET. The 220
nm luminescence can be assigned to Auger-electronfree transitions of valence electrons to Ba3 + whichis the hole of the outermost inner shell. Ion irradiations exhibited following characteristic phenomena
about the Auger-electron-free luminescence which cannot be observed in low LET irradiation. (1) The decay curve is composed of two components. (2) The'
decay time of the fast component decreased with increasing LET, while the slow one was independent of
LET. These LET effects were explained by competition kinetics between the Auger-electron-free radiativetransition and the nonradiative annihilation of Ba3 +whose process originates from LET dependent dense
free electrons. The kinetics enables us to obtain the
lifetime and yields of the core excitons. 1 ,2)
The 310 nm luminescence can be assigned to the selftrapped exciton (STE) as well known in alkali halides.
Ion irradiations showed drastic LET dependence of luminescence decay, as shown in Fig. 1. The figure shows

1000

that decay curves due to ion irradiations have fast decay components, in contrast with a simple exponentialof electron irradiation. Also, the fast component decays more rapidly with increasing LET, i.e., increasing
excitation density, while the decay curves after a few
hundreds ns coincides with the curve for electron irradiation. This effect can be explained by the STE-STE
exchange effect. Namely, the exchange interaction destroys STE nonradiatively. Such process would be thefirst finding. 2 ,3) The decay curves could be fitted bytheoretical curves, which would be the first one to deal
with distance-dependent rate constants. This may be
useful in the photochemistry such as high density excitation as wellin the same problem in solid statephysics.
(2) Track-depth resolved dynamics of excited states
In order to study depth-resolved radiation effects
along the ion track in condensed matter, we have developed a micro track scope and measured luminescence
spectra, luminescence intensity and its efficiency as afunction of ion range, stopping power, and ion velocity.
In case of near-liquid helium (helium cluster), it wasreported that the luminescence bands originate fromtransitions between Rydberg states; these states areproduced by bimolecular reactions of the lowest triplet
excimers ea). Further, it was found that at the depth
due to the maximum energy deposition, there occur
the dissociative reactions of three 3 a. Near the termination of the ion track where the ion velocity is about
1.3 times larger than that of IS orbital electron, thesecond Bragg peak for the luminescence efficiency was
found, which was explained as caused by the charge
exchange effect. 4 ,5)

as

Ar

~

5 500
u

References
Xe

Fig. 1. Decay curves of 310 nm luminescence from ion- andelectron-irradiated BaF2 single crystals at room temperature. The curves are plotted in equal heights andwith a given longitudinal shift.

1) K. Kimura and J. Wada: Phys. Rev., B48 , 15535 (1993).
2) K . Kimura: Nucl. Instrum. Methods Phys. Res., B(1993) in press.
3) K. Kimura and H. Kumagai: Rad. Eff. Def. Solids,
126, 45 (1993).
4) K. Kimura: Phys. Rev., A47 , 327 (1993).
5) K. Kimura: Nucl. Instrum. Methods Phys. Res., A327,
34 (1993).

95

RIKEN Accel. Prog. Rep. 27 (1993)

Beam End Point Measurement with Positron
Emitting Secondary Beams
T. Tomitani, M. Kanazawa, M. Sudou, F. Soga, T. Kanai, Y. Sato,N. Inabe, A. Yoshida, and Y. Watanabe
The accuracy of dose distribution in heavy ion therapy is much dependent on the range estimation of projectile ions in the target medium. Heavy ion range is afunction of the electron density of the medium. Heavy
ion range is estimated from the measured CT number
by looking up a measured conversion table. Since CT
number is a complicated function of electron density
and Z-number, there are some ambiguities in the conversion and some sorts of experimental checking means
are needed. With (3+ emitting ion beams, we can measure their end points by measuring annihilation pair ,rays with a positron emission tomography (PET). End
point distribution provides us such a checking means.
Preliminary experiments on the measurement of end
points of (3+ emitter were done at the RIKEN Ring
Cyclotron. l1C was used, since its LET is close to 12C
which will be used for heavy ion therapy at NIRS, andits half life, 20.34 min., is appropriate for the measurement. A small PET device of high spatial resolution
was used, which was originally developed for physiologic studies of animals.
The PET device used in the experiment consistsof 128 bismuth germanate crystals of 4 mm wide by
10 mm high and by 20 mm deep coupled to 64 gridded photomultipliers of 12.7 mm square. The measured spatial resolution inside the tomographic plane
is about 3 mm FWHM and that along axial direction is 2.5 mm FWHM. Since the PET device consists of a single ring, a target sample must be scanned
to measure the three-dimensional distribution. Instead of moving the detector system, the sample wasdriven by a pulse motor controlled remotely by a microcomputer. A polymethyl methacrylate (C 6 H 8 0 5 , Lucite) block was used as a target material. The Lucite
sample was engraved with two sets of characters, i.e.,'RIPS' and 'NIRS'.
The line width of character sets was set to 2 mm
which is comparable to the spatial resolution of the
PET. The depths of the character sets were set to 4
mm and 5 mm, respectively, as shown in Fig. 1. To
cover the pattern shown in Fig. 1, an 11 C beam was
defocused to about 6 cm cP. Nonuniformity of the beam
was corrected by a separate measurement of the beamprofile with a flat disk.

96

Characters

End Points

Fig. 1. Depth resolution test pattern made of Luciteengraved with two sets of characters.

The 11 C distributions corrected for the beam nonuniformity are shown in Fig. 2, in which the total number of 11 C particles was of the order of 109 . Since beam
intensity at the periphery of the field of view is weakand noise in the reconstructed images is enlarged enormouslyat the periphery, images only inside the regionof 6 cm diameter are shown in the figure. End point
distributions of 11 C were measured successfully. The
spatial resolution is limited to 3 mm cube due to the
PET resolution.
16 mm

25 mm
>

~

.

,"'. "

f'I:"

~

21 mm

26 mm
1

29 mm

Jr

Fig. 2. Distribution of 11 C at various depths from theLucite surface. Character line width is 2 mm and character height is 14 mm.

RIKEN Accel. Prog. Rep. 27 (1993)

Initial Recombination in a Parallel Plate Ionization Chamber
Exposed to Heavy-ion Beams
T. Kanai, M. Sudou, S. Minohara, and'F. Yatagai
We have installed an irradiation system at E5 roomof the RIKEN Ring Cyclotron Facility for studies ofradiation biology using heavy-ion beams. The biological and physical data are used to modify the heavy-ion
beams for the heavy-ion radiation therapy. I) In the biological studies and radiation therapies using heavy-ion
beams, an accurate determination of the absorbed doseis essential. Dosimetry for the heavy-ion beams was described in a separate paper. 2 ) Fluence of the uniform
irradiation field was measured by a plastic scintillator,and dose at the entrance position of the depth dose distribution was obtained by multiplication of the fluenceby the stopping power of the heavy ions at the position.
Then, the depth dose distribution was normalized by
the dose at the entrance position. The depth dose distributions are usually measured by a parallel plate ionization chamber. As discussed in a previous paper, 2)
initial recombination plays an important role in measuring the ionization current of an air-filled parallel
plate ionization chamber. The ion colleCtion efficiency
in the parallel plate ionization chamber is not 100%
because of the initial recombination. The LET dependence of the ion collection efficiency was measured forseveral gases and differential W-values of the gases forthe 135 MeV lu carbon and neon ions were deduced.
Two types of parallel plate ionization chamber wereused for the measurements of the initial recombination. One has an entrance window of 2.5 J.1m thick aluminized polyester sheet and the other has an entrance
window of 1 mm thick Lucite sheet. A signal electrodeof 5 mm in diameter is surrounded by a guard ring thatis against disturbance of electric field near the boundary of the signal electrode. A gap between the signal
and the high voltage electrodes is 2 mm. Usual operating bias of the high voltage electrode is 400 V, whichis 2000 V I cm electric field. The initial recombinationof the parallel plate ionization chamber depends on anangle between the heavy-ion beam and the electric fieldof the chamber. The thin-window chamber was used
for this angular dependence. Only air can be used as agas of the cavity of the chamber. The gas in the thickwindow chamber can be replaced. The recombination
for several gases was measured by this thick-windowchamber.
The chamber was irradiated by uniform heavy-ion
beams at the irradiation site of the irradiation facility. I)
Ionization current was measured by an electrometer
Keithley 617. The LETs of the heavy-ion beams werechanged by changing absorber thickness of the irradiation facility. I) Ionization currents of the parallel plate
ionization chamber were measured by changing the voltage applied to the high voltage electrode. The inverses

14 ,.--.---,--,---,~
A~
IR.....:.,~p'-,-l.,....;
us~vo.;..:.,lt.:..:.a~
ge~~

f
·a

12

I

C b

;:;!

7······ N;.~~~~ . ... ...............
..1

<)

~ 2
o ~~~~~~~~~~

oo

100

200

300

400

SOO

Dose Average LET ( k e V /~m )Fig. 1. Typical result of LET dependence of the slope ofplots of the inverse of the ionization current against theinverse of the applied high voltage at V > 100.

of the ionization current were plotted against the inverse of the applied high voltage. The data corresponding to 1/V < 0.01, that is, V > 100, can be fitted by astraight line. Decrease of the ion collection efficiency
at such a high electric field can be regarded as thedecrease due to the initial recombination.
The differential W-values of air, nitrogen, argon, carbon dioxide, and tissue equivalent gas for 135 MeV lu
carbon and neon ions were measured by the same methods described in the previous report. 2 ) The ion currents
were corrected by the recombination effect.
Figure 1 shows the results of LET dependence ofthe gradient of the slope at V > 100 for air. It can besaid that the recombination depends only on the LETof the heavy-ion beams and increases roughly linearlywith LET. The experimental data is now being analyzed using model calculation. For argon and nitrogengases, the decreases of ion collection efficiency due tothe initial recombination were not observed.
Table 1 summerizes the differential W -val ues of thosegases for 135 MeV lu carbon and neon ions.
Table 1. Differential W-values for 135 MeV ju carbon andneon ions. The results in Refs. 2)- 4) are also written
for comparison.
C 135McVIu

Air
N2

Nc 135 McV/u
34 .2 cV
36.6 cV
24 .3 cV
21.9 cV
29.3 cV
4Hc 18.3 McV/u 4 )33 .S cV
3S .8cV
AI 23 .6 cV
C02 21.4 cV
TEG 28 .6 cV

PbotonlElcctIon 3)
33 .85 cV
34 .8 cV
23 .8 - 26.4 cV
33.0cV29.2 cVTEG 29.2 +1- 0 .9 eV

C 129.4 McV/u 3Hc 10.3 McV/uAir

33 .7 +1· 0.9 cV 34 .S +1- 1.0 cV

C 6.7 MeYlu 2)
36.5 cV +1- 1.0 cV

References
1) T. Kanai et al.: HIMAC report 004 (NIRS-M-91) NIRS
publication, (1993) .
2) T. Kanai et al.: Radiat. Res., 135, 293 (1993).
3) ICRU report 31 (International Commission on Radiation
Units and Measurements, Washington) (1979).
4) T. Kanai and K. Kawachi: Radiat. Res., 112,426 (1987).

97

RIKEN Accel. Prog. Rep. 27 (1993)

Ionization Tracks Produced by Ar (95 MeV lu) Ions and their
Core-Penumbra Structure
M. Suzuki, T . Takahashi, and K. Kuwahara
Since the ionization track structure produced byheavy ions is of great importance in radiobiology, many
works have been done to answer the question whether
the ionization track manifests the two distinctive distributions, i.e., "core-penumbra" structure,1) or a single continuous distribution obeying, for instance, thel/r2 law. Theoretical works based on Monte Carlocalculations claim that there is no evidence of an enhanced energy deposition in the center of the tracks. 2 )Recent micro dosimetric experiments are also in favorof the l/r2 law. 3 ) However, the accuracies of the calculations and the experiments are limited by the availability of the electron-atom interaction cross sections
and by the smallest feasible detection volume, respectively.
In order to finalize the issue, therefore, one needs
new instruments or techniques which can reveal theionization track structure in detail. As a promising
instrument, we have proposed and constructed a proportional scintillation imaging chamber (PSIC) which
provides high quality photographic images of the ionization tracks in real time. 4 ) The PSIC has been successfully operated at the E5A beam line of RIKEN
Ring Cyclotron, detecting the ionization tracks produced by N (135 MeV lu) ions and Ar (95 MeV lu)
ions.
Figure 1 displays the lateral brightness variation of
the observed ionization track image produced by the
Ar ion. The figure demonstrates that the ionization
track has the core-penumbra structure. We have fitted
the brightness curve to the double Gaussian elect ron
density distribution function, p(r) , given asIp(r) = No [ 7rbi exp(1'2) 1 - I (1'2 ) 1,
- bi + 7rb~ exp - b~

where l' denotes the radial distance, No a constant , bi
the core radius, b2 the penumbra radius , and I the40, - - - - -~ 35- - - - - - -- - - - ,Ar ( 95MeV/ u) Ion

.~

;I 30

C

£ 2S

relative fraction of the number of the secondary electrons in the core to the total number of the secondary
electrons. The best fitted curve is shown by the solid
curve in Fig. 1, and the best fitted values for I, bl , andb2 are listed in Table 1 together with those calculatedby Magee and Chaterjee. 5 )Table 1. Ionization track parameters.

fpresent
theoretical 5 )0.49 ± 0.1
0.5

3.7 ± 0.4
0.003

25 ± 323

As can be seen from Table 1, the I-value determinedin the present work is very close to 0.5 , indicating thatthe equipartition holds under the present experimental
conditions. The b2 -value obtained is also in good agreement with the 'calculated one. Since b2 corresponds tothe typical 8-electron range in the medium, one could
infer that the energy of the typical 8-electrons is 50
keV for the Ar ions.
The bl-value determined in the present work is, on
the other hand, three orders of magnitude larger thanthe calculated one. From a theoretical view point, it isnatural to define bi as the radius of the cylinder about
a heavy ion trajectory in which the resonant electronic
excitation occurs. The secondary electrons created in
the cylinder, however, will disperse by the randomwalk process in background gas while thermalizing.
At the time of the observation the electrons shouldhave completed their thermalization process, so thatthe bl-value determined experimentally includes thethermalization length, Lth ' which is much larger thanthe bl-value defined theoretically. One could, therefore, interpret the experimental bi - val ue as L th , which
is about 4 mm for the present study. In order to verify
our understanding, it would be worthwhile to compare
the ionization track parameters among various highenergy heavy ions. Data analysis on the N ion images
currently in progress will provide us with further information upon the core-penumbra model.

;Q

~ 20

References

~ 15
c:

i lO

~ 5
4

5

6

10

Lateral Direction (cm)Fig. 1. Lateral brightness variation of the observed imageof ionization track produced by Ar (95 MeV lu) .

98

1) A . Chaterjee et al.: Rad. Res., 54, 479 (1973).
2) M. Kramer and G. Kraft: GS/91-1 , 205 (1991).
3) N . F. Metting et al.: Rad. Res. , 116, 183 (1988).
4) M. Suzuki et al. : RIKEN Accel. Prog. Rep., 26 , 116(1992) .
5) J. Magee and A . Chaterjee: J. Phys. Chern., 84, 3529
(1980).

RIKEN Accel. Prog. Rep. 21 (1993)

Calibration of CR-39 Track Detector for Space RadiobiologicalStudies and LET Measurements of Cosmic Ray Nuclei
K. Ogura, T. Doke, K. Kuwahara, M. Matsushima,* S. Nagaoka,**
K. Nakano, M. Suzuki, T. Takahashi, H. Yamada,* and F. Yatagai
In the complex radiation field in space, the so-called
HZE (high Z and high energy) particles are of special concern to the space radiobiological studies. During the First Material Processing Test (FMPT) space
shuttle mission in September 1992, Japanese Radiation
Monitoring Container & Dosimeters (RMCD) accommodating biological samples and CR-39 track detectors were exposed to cosmic radiations while the space
shuttle Endeavour stayed for about 7 days in the orbit
at about 300 km altitude with the inclination of 57°.
Figure 1 shows the response curve of a CR-39 track
detector, which was obtained by the irradiations of
C, N, Ne ions with energies of 135 MeV/nucleon and
95 MeV/nucleon Ar ions from the RIKEN Ring Cyclotron. The low LET region of the response curve wasobtained by 10 MeV proton exposure at the TIARA
Cyclotron of JAERI, Takasaki.

where Be is the maximum detectable zenith angle anddepends on the LET value of the incident particle. The
effective detection threshold of LET 00 values in water
was reduced down to about 4 keV / J-lm due to the highsensitivity of our CR-39 detector as shown in Fig. 2.

10-3

FMM"

... :DA+ :DB"'e..::, 10-5--~
i 10-6
t'l

~ 10-

Jl..

7

10-foo

1Q1

102

103

LET",(ke V/ fJ. m water)

Fig. 2. Observed integral LET-spectra inside the RMCD
on FMPT and calculated spectra (solid lines) behindshieldings of 10,20,30, and 40 g/cm 2 of CR-39 (Wiegel
et al., 1988).

LET200eV( MeV cm2g- 1 )Fig. 1. Response curve of the detector: reduced etch rate
ratio vs. LET200ev in CR-39.

After the mission, CR-39 detectors were etched in a
7N-NaOH solution at 70°C for 30 hours and analyzed
by using an image processor. The LET200ev value in
CR-39 for individual particles was computed from thereduced etch rate ratio of the track using the response
curve of the detector in Fig. 1. The measured data of
LET 200eV in CR-39 were converted to the total energy
loss LET 00 in water. In Fig. 2 we present preliminary
results of the measured integral LET spectra. The
effective solid angle (0) of the detector is defined byo = 7r(1 - cos 2 Be),*

College of Ind. Techno!' Nihon Univ.

** Nat!. Space Dept. Agency of Japan

Figure 2 additionally shows the calculated LET
spectral) behind different amounts of shieldings.
These model spectra were calculated for the German
Spacelab in a circular orbit at 324 km altitude with aninclination of 57°. These are almost the same mission
parameters as for the FMPT mission. Taking accountof the data of neutron monitor2) and the intensities
of protons observed in space,3) the influence of solar
modulation on galactic cosmic rays can be consideredas almost the same in magnitude at the period of bothmissions. Our spectra are very similar to the calculated spectra over the entire LET range. Moreover,the shoulder position of the spectrum due to the minimum ionizing cosmic iron ions appeared around 130
ke V / J-lID and agrees well with the model predictions.
From Fig. 2 we can also estimate the total amountof the effective shieldings of the detectors inside the
RMCD to be approximately 20 g/cm2 of CR-39.
References
1) B. Wiegel et al.: in "Terrestrial Space Radiation and Its
Biological Effects", edited by P. D. McCormack et al.,Plenum Press, p. 795 (1988).
2) R. A. Mewaldt et al.: Pmc. 23rd JCRC (Calgary), 3,
404 (1993).
3) Z. Fujii and F.B. McDonald: ibid., p. 477.

99

RIKEN Accel. Prog. Rep. 27 (1993)

Radiation Effects of Ion-particles on Various DNA Structures
S. Kitayama, M. Kikuchi, K. Nakano, M. Suzuki, T. Takahashi, and H. Watanabe
Ionizing radiation including accelerated particles induces various damages in DNA such as hydroxylationof base and sugar, disruption of phosphodiester bonds,
etc. However, living cells repair the most of them except lethal damage which has not been clearly identified. From the technical limitation to analyze thechange of molecular structure of long DNA in living
cells, the biological effects of radiation have been studied mostly on the changes of DNA molecules whosemolecular weights are less than 10B(rv 1.5 X 105 basepairs). Recent technichal progress in the analysisof large DNA such as pulse field gel electrophoresis(PFGE) makes it possible to measure the molecularchange of long DNA bigger than rv 107 base pairs.
Even though prokaryotic cell has no nucleus its single molecule of double-stranded DNA, corresponding
to one chromosome, is folded extensively within a small
cell envelope. Many cellular constituents are thought
to be associated with the folded DNA. It is still unknown whether any segments of chromosomal DNA
molecule are evenly attacked by radicals produced byradiations or whether cell constituents protect it or enhance the radiation damages. As reported last year(l),we carried out the experiments to confirm the differrent
radiation effecs on "naked", "folded" or "packaged"
DNA. We found by electron-microscopic observationthat DNA , after removals of RNA and proteins, is stillenveloped in an agarose hole whose diameter is almost
the same as that of intact cells. Therefore, it can bethought that the DNA in the "naked" sample is still
folded in a small space corresponding to the single cell.
Therefore, the name of "folded" must be changed to"cell wall and RNA free" sample as a more appropriate
terminology.
In order to compare the radiation effects of N-ions( rv 135 MeV /J.L) on these three folded forms of DNA ,cells of Deinococcus radiodurans were solidified withagarose (DNA is still "packaged" in a cell with its constituents). Before the irradiation the cells were lysedwith lysozyme in the presence of RNase ("cell wall
& RNA free") followed by proteinase K treatments( "naked" ). RNA and proteins were removed by the in-100

cubation with these enzymes following the ittadiation
and DNA were digested with a restriction endonuclease, Not 1. The digested fragments (Not I fragments)
were analysed by PFGE as shown in Fig. 1. At least
two conclusions can be drawn from the figure; (1) DNA
in "cell wall & RNA free" sample is the most sensitive
to N-ion bombardment, (2) Among the Not I fragments
the biggest fragment (ca 480 kbp) is more sensitive toit than the others (400, 390, 360, 324, 255 , 240, 225 ,
215 , 109, 102, 100 kbp). After completing the more detailed experiments these results will be analyzed quantitatively using densitometer tracing and will be also
compared with the effects of low LET radiation suchas gamma-rays.
- - - d i rect i on of e I ectrophores i s
1 2 3 4 5 6 7 8 910
A - I adder DNA marker

o Gy
100 Gy"pakaged"

Gy
Gy

Gy

Gy "cell wall & RNA free"
Gy
Gy
Gy
Gy

"naked"Cy
Gy
Gy

Fig. 1. Disappearance of Not I fragments in three different
folded forms of DNA after the irradiation with N+ -ions.
The molecular weights of .A-ladder DNA size standard
shown in the figure are as follows (bp): 1 = 48.5k, 2 =97.0k, 3 = 145.5k, 4 = 194.0k, 5 = 242.5k, 6 = 291k, 7= 339.5k, 8 = 388.0k, 9 = 436.5k, 10 = 485.0k.

References
1) S. Kitayama et al.: RIKEN Accel. Prog. Rep., 26 , 103(1992).

RIKEN Accel. Prog. Rep. 27 (1993)

Studies on Induced Mutations by Ion Beam in Plants
Induced Mutants of Rice Resistant to Bacterial Leaf Blight
H. Nakai, H. Watanabe, Y. Kobayashi, S. Kitayama, T. Takahashi, and T. Asai*
Bacterial leaf blight(BLB) of rice caused by Xanthomonas campestris pv. oryzae is one of the most important diseases seriously affecting the production ofrice in rice growing areas all over the world. 1) M3 (thethird generation after mutagen treatment) lines of rice
derived from the M2 BLB resistant plants, which originated from the seeds irradiated by ion beams 4 N+),
thermal neutrons and gamma-rays, were grown in theexperimental rice fields of Shizuoka University to be
inoculated using the BLB isolate T7133. 2 ) The inoculated plants of every line were scored for disease severity by measuring the length of the lesions 3 weeks after
inoculation and the lines which showed resistance to
BLB were selected.
The results are presented in Table 1. In the table,
frequency of the resistant mutants was calculated bynumber of resistant lines selected/number of total M2
seedlings analyzed. It was noted that the frequencyof BLB resistant mutants in the treatment of the ion
beam as significantly higher than that in the other mutagen.

e*Table 1. Frequency of bacterrial leaf blight resistant mutants of rice in the mutagens of ion beam, thermal neutrons and gamma-rays.
MutagenDose(krad)Seed
No. ofNo. of Frequency
fertility
M2
Plants of resistantin Ml (%) Seedlings* selected mutant
52
30,0008
2.6 x 10 4
1053
30,0003
1.0 X 10- 4
1.0-1.5

Ion beam
ThermalneutronGamma-ray30* No. of seeds sown

49

15,0003

2.0 X 10- 4It can be concluded from the present experimentthat ion beams could be very effective mutagen for
induction of useful mutants for the plant breeding.

References
1) H. Nakai et al.: J. of Agricultural Sci., Gamb., 111, 309(1988); ibid., 114, 219 (1990).

2) H. Nakai et al.: RIKEN Accel. Prog. Rep., 25, 110(1991).

Shizuoka University

101

RIKEN Accel. Prog. Rep. 27 (1993)

Effect of HZE Particles (Ar, N) on Hatching Rate andOccurrence of Pycnosis of Artemia salina
M. Ishikawa and F. Takashima *This experiment was planned to obtain fundamental
data for the establishment of a biological monitoring
system of cosmic radiation in space; especially to examine the effect of HZE particles on biological activity.
Artemia salina was chosen for its toughness to environmental change: the eggs can survive more than several
months under dry condition.
Although Artemia salina is popular in radiation biology, the data of the effect of HZE particles on its biological activity is not available. In the present study,
we examined the effect of the energy of Ar and N ionson the hatching rate and the occurrence of pycnoses ofA rtemia salina.
Eggs of Artemia salina were stuffed in holes of 9
mm diameter of plastic plates (lmm-t hick, track detector) and sandwiched between appropriate numberof the same plastic plates without holes (Fig. 1) . In
order to examine the effect of energy, the samples werestacked; the nearer the sample to the incidence surface,
the higher the energy of the beam.

0.8~ 6.
~...

0.6Iil~ 6.

o.•

01)

.50.4

~

...

A

...

/).

/).

/).

o No. 20o No.40• No. 3

0

•

:J:
0.2

... No.500• •~--.-.--.--'
0

0.0
0.0

14

particles/m 2 )Fig. 2. Hatching rate of Artemia salina. Ar (88 MeV).

0.9

•

~o 0

0.8

~ 0.7

•

[

o No.20.6

0.

'0 0.5
8

•

•

0

•

<>.
o
0.2 <>~ 0.3

1111110.1

0.0

Sample number

3

Sample stack-N~
II

4 5 6 7I I IIIII I IIIII,~'-'
15plar.es

6platesFig. 1. Sample stacks.

After the exposure of Ar or N beam, the samples
were kept at 3 ° C before the deternination of hatching rate and occurrence of pycnoses. The hatchingrate was determined after incubation at 25 °C for 48
hours in artificial sea water. The nauplii were dyedand served for microscopic observation to count thepycnoses.
The hatching rates of A rtemia salina exposed to Ar
ion beams were plotted against the dose in Fig. 2. The
hatching rate decreased with increase of the dose except two groups of samples of which the beam energy
was lower.
The occurrence of pycnoses of A rtemia salina was
depicted in Fig. 3. The occurrence of pycnoses correlated with the energy of the beam when the dose was*
102

JJ.. No. 5

D. No.6¢
1.0

Dose (10I 2 3 4 5 6

Dept. of Aquatic Biosciences, Tokyo Univ. of Fisheries

No.3

JJ../:l't.

o.o ~111111

No. I<> No.4;;~/). No.6

3.0

2.0

1.0

Dose (10~ 0.4

Sample stack-Ar• No. I

...

2.'0
14

3.0

particles/m 2 )Fig. 3. The occurrence of pycnosis in Artemia salina. Ar(88 MeV).

less than 5 x 10 13 (particlesjm 2 ) , however the occurrence of pycnoses of samples exposed to larger dose
was small.
The hatching rates of A rtemia salina exposed to N
ion beam were shown in Fig. 4.

Fig. 4. Hatching rate of Anemia salina N (135 MeV).

RIKEN Accel. Prog. Rep. 21 (1993)

Chromosome Aberrations Induced by 135 MeV Carbon and Neon
Beams of RIKEN Ring Cyclotron in Human Blood Cells
H. Ohara,* M. Minamihisamatu,** T. Kanai,** K. Eguchi-Kasai,**
K. Fukutsu,** H. Itsukaichi,** F. Yatagai, and K. Sato**
Chromosome aberrations,which were induced in human blood cells after irradiation with carbon and neon
ions (135 MeV In) produced by RRC, were examinedat the first post irradiation mitosis in order to establish a dose response of the aberration frequencies/cellvs change in LET. Studies on the difference in frequencies of chromosome aberrations with ions as wellas LETs might bring us some cell biological aspectsof the radiation damage induced by high LET particle
beams.
Figure 1 shows the data of dose responses for frequencies of dicentric plus ring type aberrrations percell after irradiation with four different ion beams at
different LETs. Among them, one is neon beams with
70 Ke V / J..Lm of LET (closed squares) and the otherthree curves are all with carbon beams at different
LETs. All of the curves were obtained by fitting theaberration frequencies to the linear quadratic modelof y = aD + f3D2 + c. The results indicate that
all curves were fitted well with high correlation coefficients (r = 0.88- 0.99). Thus, following conclusions
might be drawn from the present study. (1) As LET
increases, an upward concave curve of dose response,
which is seen typically for such a low LET beam, turns
first into a downward concave curve and further intoa linear type. Such a change of dose response was observed in the present study with high LET carbons

5
>-

u

c:

II)

:::J
C"

II)

.t

3

c:

~

~

2

~

.Q

oct

7

Irradiation Dose (Gy)Fig. 1. Dose response curves of dicentric and ring typesof chromosome aberrations against different LETs ofparticle radiations produced by RRC. Abs. 0, Abs. 24,
and Abs. 32 refer to those carbon ion beams with LETsof 22.4, 41.5 , and 69.9 KeV / }-Lm , and Ne refers to theneon beams with 70.0 KeV / }-Lm. All curves were fitted
to linear-quadratic model equations.

*and neons. Similar types of linear response have been
already observed either with neutrons 1 ) or with such
X-rays with absorption energy to cause high densityof ionizations by kicking out of K-shell electrons. 2 ) A
question, however, is whether the saturation of aberration that was observed in the curve of open squares
for 41.5 Ke V / J..Lm of LET beam is true or not. The
saturation in the production of aberrations somehowmeans that the cells which received the aberrations
more than the saturated level cannot survive to pass
the first mitosis after irradiation, i.e., they are definitely damaged to allow an interphase death. On theother hand, the two beams of neon and carbons withhighest LET showed incrementally high frequencies ofaberrations without saturation not like the one withlow LET, which means that the cells are not definitely
damaged at least for ability to enter the first division
after irradiation. (2) The dose response for dicentric
and ring aberrations was observed different with ion
species though the dose-average LET was amost thesame. It was clear that the neon curve showed a higher
rate of aberration production than the carbon's withthe same LET (69.9 KeV / J..Lm). This result suggeststhat a high rate of aberration production may not always inhibit the ability of cells to enter mitosis. The response of the cells irradiated with neon beams is clearly
due to the beam difference, probably being related tothe track sturucture and the associated change in ionizing densities. (3) The RBEs which were estimatedrelative to the response of the lowest LET carbon ion
beams, were 2.45 for neons, 1.67 for the highest LET
carbons and 1.16 for the second carbons. These results indicate that biological effects of particle beams
might be dependent on fluctuations in LET or ionizing
density as well as those of track structures and otherphysical qualities of beams suggested in other report. 3 )More detailed studies are in progress .
References
1) Y. Matsuda, H. Ohara, and I. Tobari: Mutation Res.,
116, 251 (1987).
2) H. Ohara, K. Shinohara, K. Kobayashi, and T. Ito:in "DNA Damage by Auger Emitters", ed. by K. F.
Baverstock and D. E. Charlton, Taylor & Francis Ltd.,
London, p. 123 (1988).
3) G. Kraft, M. Kramer, and M. Scholz: Radiat. Environ.
Biophys., 31, 161 (1992).

Dept. General Education , Okayama University** Natl. lnst. Radiol. Sci.
103

RIKEN Accel. Prog. Rep. 27 (1993)

Molecular Characterization of Mutations in Human Cells
Irradiated with Carbon Ions
M. Watanabe, M. Suzuki, Y. Kase, and F. Yatagai
Several studies have focused on the molecular structure of radiation-induced mutations and have foundthat the most common lesion is a large deletion ofgenetic information. However, only a few studies
have been reported in the literature determining how
the molecular structure of radiation-induced mutations
is affected by heavy ions. We previously reported
that heavy ions were generally more effective in cellkilling, chromosome aberration induction, mutation induction and neoplastic cell transformation induction
than gamma-rays in SHE cells. 1-6) It is clear from track
structure studies that heavy ions can deposit large
clusters of ionization in DNA which may produce qualitatively different types of initial damage from those
produced by the sparsely-ionizing X- or gamma-rays.
It is of considerable interest, therefore, to examine thenature of mutations induced by heavy ions in comparison to those induced by gamma-rays. In this study,
we detected mutation induction at hprt locus in humancells irradiated with carbon and neon ions with several
LET and examined the molecular characterization of
mutations.
Primary human embryo (HE) cells were irradiatedat confluence at room temperature (20°C). The carbon ions were generated by the ring cyclotron at theInstitute of Physical and Chemical Research (RIKEN)
and the cyclotron at National Institute of Radiological
Science (NIRS). The fluence of carbon ion beams wasmeasured with a plastic scintillator and the value of
LET was measured with a proportional counter filledwith tissue equivalent gas. The energy of carbon ion
beam was 135 MeV In (RRC) and 12 MeV In (NIRS).
We changed LETs of beams by changing the Luciteabsorber thickness. LET values at the sample position
were estimated to be varied from 22 to 230 ke V I/-Lm.
The dose rate was about 1 Gy Imin in all beams.
The incidence of mutation in cells irradiated withcarbon ions was higher than that in cells irradiatedwith 137 Cs gamma-rays. The RBEs, compared to
137CS gamma-ray, were between 2.7-7.2 for carbon ionswhen they were compared at the same absorbed doselevel and the highest value was 7.2 for 124 keY I /-Lm
carbon ions. DNA isolated from 129 independently derived mutants was examined by the polymerase chain
reaction (PCR). Primers for 8 exons of human hprt
gene were used in a multiplex reaction to show rapidly
whether the mutants carried deletions at these site.
A few deletions were found among the spontaneous104

mutants, while 'total' gene deletions formed in about
half the mutants found after irradiation. At equilethal
doses little difference in mutant spectrum was found
for the gamma-ray set compared to the carbon ion set.
In the case of mutants induced by carbon ions , theproportion of complete deletion mutants was dependent on the LET of carbon ions. All mutants inducedby 124 ke V I /-Lm carbon ions were whole gene deletions,while all of mutants induced by 230 ke V I J.Lm carbon
ions were not delet ions.
It is surprising that no deletion mutants were foundafter the irradiation of carbon ions at 230 keY I /-Lm
which gives the biggest track structure among all ofcarbon ions used in this study. In addition the 68 and
124 keY I /-Lm carbon ions are inducing deletions of all 8exons. It may be that for mutation endpoint , which requires cell viability for recovery, only moderate clusters
of energy deposition in DNA from carbon ions are responsible; these damage events may overlap in severity
with damage from gamma-ray track ends. Since large
clusters of energy deposition from higher LET radiation may be dominantly lethal, it is likely that only
low clusters of energy deposition from secondary electrons may be responsible for mutants induced by 230
keV I /-Lm carbon ions.
In the present study we reported that different LETsof heavy ions have different mutation spectra. Suchphenomena require critical examination using large
numbers of independently-isolated mutants; it is clearthat the methods introduced in this report may be used
to examine the such aspects of comparative mutagenesis, also to examine the biological meaning of track
structure of heavy ions, where many mutants need to
be rapidly assessed at the molecular level.
References
1) M. Suzuki, M. Watanabe, K. Suzuki, K . Nakano, and I.
Kaneko: Radiat. Res. , 120, 468 (1989).
2) K. Suzuki, M . Suzuki, K. Nakano, I. Kaneko, and M.
Watanabe: Int. J. Radiat. Biol., 58, 781 (1990).
3) M. Suzuki, M. Watanabe, K. Suzuki, N. Nakano, and K.
Matsui: ibid. , 62, 581 (1992).
4) M. Watanabe, V. M. Maher, and J. J. McCormick: Mutation Res. , 146, 533 (1985) .
5) M. Watanabe, M. Suzuki, K. Suzuki, and K . Watanabe:
In vitro Toxicol. , 4 , 93 (1991).
6) M. Watanabe and K. Suzuki: Mutation Res. , 249, 71(1991).

RIKEN Accel. Prog. Rep. 27 (1993)

RBEs of Various Human Monolayer Cells Irradiatedwith Carbon Beams
H. Ito, S. Yamashita, 1. Nishiguchi,* N. Shigematsu,* W. J. Ka,* F. Yatagai , and T. Kanai
Most biological studies for carbon beams were performed with mice and rodent cells. However, irradiation effects of X-rayon human cells are something different from those on rodent cells; for example, smaller
initial shoulders and smaller Do values for human cells.
This study was performed to determine the RBEs ofcarbon beam irradiation on various human tumor cells
in vitro.
Thirteen human tumor cell lines were used in thisstudy (4 from squamous cell carcinoma and 9 fromadenocarcinoma). They were maintained in the F-10
medium supplemented with 10% fetal calf serum bytransferring cells into new vessels once a week. For irradiation experiments, RIKEN Ring Cyclotron and the
Shimazu X-ray machine were used. A dose responseof cell survivals was determined for carbon beams atvarious LETs, and the several parameters of cell inactivation were caluculated. The curve fitting was madeby a multitarget model for Do, nand Dq.
There is a good correlation between the biologicaleffects of heavy particle irradiation and LET. However, when LET is so high, this correlation cannot be
maintained because of the overkill phenomenon. The
biological experiments with carbon beams were performed at various LETs that do not make overkill.
RBE of some test radiation compared with X-rays isdefined by the ratio of the doses of standard X-rays
and the test radiation required for the equal biologicaleffect. In this sutdy, we have used 200 KVp X-rays
as standard radiation. For convenience, doses required
to produce surviving fractions of 0.1 or 0.01 have beenused for RBE estimation and qualities of carbon beams
at various LETs were compared. RBE can be determined easily if the relationship of biological effects V.s.
irradiation dose is established.
Figure 1 showed the survival curves of two cell lines(TE 5 & A 43.1) irradiated with 200 KVp X-ray andcarbon beams at various LETs. These cells had similar "n" values (1.7 vs. 1.5) but different radiosensitivities (Do: 1.38 Gy vs. 2.43 Gy) for X-rays. Whenthey were irradiated with carbon beams, the survival
curves became steeper and Do values decreased withincrement of LETs in both cell lines. The initial shoulder of the TE 5 survival curve disappeared at a lower
LET of 20 Ke V / j.Lm. On the other hand, A 43.1 cells
showed the initial shoulder even at a higher LET of 80
Ke V / j.Lm. The TE 5 cells irradiated with 20 Ke V / j.Lm
carbon beams showed RBE of 2.54, and the A 43.1
cells, 1.70. This result suggested that the irradiation
effects of carbon beams on human tumor cells were*too 200KVp X-fay• 20KeV Carbon... 40K.eV·80KeV

c

.2
'0

0.1

tt

4

680

2

4

6

8

Irradiation Dose (Gy)Fig. 1. Survival curves of TE 5 and A 43.1 cells.

different among each cell line. RBE values at 10%
survivals irradiated with LET of 20 Ke V / j.Lm showed
1.31-2.54, and those with 80 KeV / j.Lm, 2.24- 4.07 (Fig.
2). Nine cell lines were established from adenocarcinoma and 4 from squamous cell carcinoma. There
was no relationship between histology of tumor andRBE. It is necessary to analyse the relationship between RBEs and radiosensitivities of X-ray in the next
step. When RBEs determined by in vitro experiments
are applied to clinical radiotherapy, it is very difficult
to determine the average single RBE value even forthe some LET values in the heavy particle therapy,
because the RBEs were different from one cell line toanother.
@'~-40.01 Survival

0.1 Survival

'0
.!
in

10

20

40

60 80

10

20

40

60 80

Linear Energy Transfer (lET) (KeV)

Fig. 2. Relationship between RBE and LET. RBEs of
13 human tumor cells were determined at 0.1 and 0.01
surviving fraction.

Dept. of Radiology, Keio Univ., School of Medicine

105

RIKEN Accel. Prog. Rep. 27 (1993)

Sensitivity of ts85 Mutant Strain from Mouse FM3A
Cells to Heavy Ions
F. Yatagai, K. Nakano, T. Kanai, K. Saito, and F. Hanaoka
One of our interests in elucidating biological effectsof heavy-ions is to get some insights into the induced
DNA damages in mammalian cells. In Saccharomyces
cerevisiae, RAD 9-dependent response detects potentially lethal DNA damages and causes arrest of cells
in G2 until such damage is repaired. 1) The mutationin RAD 6, ubiquitin-conjugating enzyme E2, expresses
the phenotype of G 2 block through the lack of chromatin condensation. Interestingly, the RAD 6 geneof Saccharomyces cerevisiae also plays a key role in
postreplication repair of numerous chemical and physical DNA damages including UV- and X-ray induced
lesions. 2 ) The ts85 mutant strain from mouse FM3A,3)
defective in ubiquitin-activating enzyme El, represents
the defects in the early step of chromatin condensation.
The ts mutant cells as well as their wild-type were irradiated with ions of C and Ne to study the contributionof this gene product to the repair of heavy-ion damages.

The cell suspension was exposed to C- or Ne-ion.
The irradiated cells were plated and incubated at 39°c for 20 hrs for the induction of ts phenotype andthen shifted down to 33 ° C (developed by Dr. H. Ikehata). As the phenotypically non-expressed control,
the plates were also incubated at 33°C without theabove shifting up to 39 cc. The survival curves for Cions were shown in Fig. 1. In contrast to UV (data notshown), the survival curves for ts85 mutant, shifted up
to 39°C at the incubation, represent almost no sensitization compared to the curves of non-expressed cell, incubated at 33 °c following the irradiation. This characteristic was also observed with 63.3 KeV / 11m Ne-ions(data not shown). The tendency of LET-dependent
sensitization by the temperature shift would be observed even with this sort of limited experiments if thismutant cell was sensitized by the 8-ray effect. In fact ,this mutant cell irradiated with X-rays did not show
any sensitization (data not shown). Before getting theMouse FM3A

Mouse FM3A ts85

10o~~----------------------

LET; 22. 5KeV/~m : 150KeV/~m--e- 33 • C ----- 33' C
c
o

U
ctl

U::
OJ

c

->

.~

:J
(j)

10- 1

LET; 22.§~: 150KeV/J.IlTl~33'C-+-33'C

2

3

Dose (Gy)

60

234

5

6

7

Dose (Gy)Fig. 1. The survival curves of FM3A and its ts mutant ts85 cells for carbon ion.

conclusion that the function of ts85 mutation is, if notall, different from that of RAD6 in yeast, we have tocheck the detailed experimental conditions, for example, recovery of the lethal damage due to the delay instarting the incubation at 39°C, scavenging effect ofthe medium during the irradiation, etc. The present
experimental results also suggest that DNA damages

106

are, at least, different from UV damages.
References
1) T. A. Weinert and L. H. Hartwell: Science, 241, 317(1988).
2) L. Prakash: Mol. Gen. Genet., 184, 471 (1981).
3) T. Eki et al.: J. Biol. Chern., 265, 26 (1990).

RIKEN Accel. Prog. Rep. 27 (1993)

PLD Repair in Tumor Cells after Carbon Beam Irradiation
N. Kubota, M. Kakehi,* S. Matsubara,* F. Yatagai, T. Kanai, and T. Inada**
It is well known that mammalian cells repair radiation damage by two known processes: Sublethal damage (SLD) repair and potentially lethal damage (PLD)
repair. 1) Modification of SLD repair with increasing
LET has been investigated extensively, but modification of PLD reapir with increasing LET has been studied only to a limited extent. The results of these PLD
experiments, in contrast to the severely reduced repair of SLD, are uncertain and discrepant. Because
recovery from PLD might significantly contribute to
the ultimate therapeutic response of a solid tumor, wehave investigated the ability of plateau phase humanosteosarcoma cells (M G-63) to recover from PLD after irradiation with carbon ions, accelerated by the
RIKEN Ring Cyclotron, with the spread-out Bragg
peak (SOBP) and unmodulated plateau. The physicalcharacteristics have been descrived in detail. 2) The reference radiation was Cs-137 ,),-rays from the GammaCell 40. Cell survival was measured by the standard
colony-formation technique. Plateau phase cells wereprepared by plating 5 x 105 cells in a T25 flask andincubated for 5 days without an intervening cf.l.angeof medium. For the PLD repair experiment, plateau
phase cells were trypsinized at various times after theirradiation.
Cell survival was measured for plateau phase MG63 cells at various depths (entrance, proximal, midpoint, and distal) in the SOBP of carbon beam. Doseresponse curves measured by 24 hr delayed plating are
given in Fig. 1. RBE values calculated at 10% survival
level were 1.7, 2.5, 2.7, and 3.2 at entrance, proximal,
midpoint, and distal within the SOBP. Corresponding
RBE values at 1% survival level were 1.5, 1.9,2.1, and
2.5.
Results of the PLD repair in plateau phase MG-63
cells at various depths in the SOBP of carbon beam
and ,-rays are shown in Fig. 2. After ')'-ray exposure,there was an increase in survival with time. The recovery ratio, measured by the ratio of cell survival by
24 hr delayed plating to immediate plating, was 7.0.
After carbon beam irradiation, recovery was found to
be reduced, and the ratios were 6.1, 3.2, 3.0, and 3.4
at the entrance, proximal, midpoint, and distal within*

the SOBP, respectively. Thus, our results clearly
demonstrated that there was still detectable PLD repair when plateau phase MG-63 cells were exposed tocarbon beam.

:'"

!~~\.

0.1

z

~: \

0

i=

+~

~

II:

u.

(!l

Z

:;

~

0.01

;:)
CJ)

\

t 0\ \

+

\ \

\

nn,

o EDtn.nc~

6 Pro_oJ SOBPo MId SOBP
• Dis... SOBP

0.001
0

2

4

8

6

10

12

DOSE(Gy)

Fig. 1. Cell survival by 24 hr delayed plating of plateau
phase cells afer carbon beam and ')'-ray irradiation.

20
0

10

II:

5

~

>w
>

/.:-----~=

¢/~

II:

~-

i'

0

(,)

W

II:

. l-rayo Entrance
6 Proximal SOBPo Mid SOBP
• Distal SOBP

0.5
0

6

12

18

24

30

INCUBATION TIME (Hr)Fig. 2. PLD repair after irradiation with carbon beamand ')'-rays.

References
1) N. Kubota et al.: Int. J. Radiat. Biol., 54, 221 (1988).
2) T. Kanai et al.: Proc. 2nd Workshop on Physical andBiological Research with Heavy Ions, p. 1 (1992).

Yokohama City Univ.

** Univ. of Tsukuba
107

RIKEN Accel. Prog. Rep. 27 (1993)

The Early Skin Reaction after Carbon Ion Slit-Beam Irradiation
H. Tatsuzaki, T. Okumura, H. Takahashi, T. Kanai , S. Minohara, M. Sudou, and F. Yatagai
The tolerance dose of an organ depends on manyfactors including LET (linear energy transfer) and irradiated volume. The effects of irradiated volume ona tolerance dose with different LET beams should beclarified to develop better radiation therapy. To study
the above point, this experiment was performed usinga skin of mouse as the target organ system.
Materials and methods
Twelve week old female C 3 H/He SIc mice were used
for this experiment. The animals are raised under aspecific pathorgen free conditon.
All the irradiation was performed using RIKEN Ring
Cyclotron. Two radiation beams with different LET
were used. One was the entrance plateau portion ofan original mono-peak beam of a 135 MeV lu C-ion
beam and the other was the middle portion of three cm
spread out Bragg peak (SOBP) from the same C-ion
beam. This SOBP was produced by a rotating range
modulator. The flatness of SOBP was adjusted biologically so as to get 10% survival of V79 cells uniformly. I)
The LET values of these beams at skin surface werearound 22 ke V I j.t and 71 ke V I j.t, respectively. The
beams were collimated to 25, 15, or 5 mm wide slitshape with a copper final collimator (Fig. 1). In thisway, irradiated volumes were changed. The lower hint
legs of mice were irradiated under anesthesia using 65
mg/kg sodium pentobarbital i.p. injection.

diation effect. Seven days before irradiation, thelower hint leg of the mice was shaved using a razor
blade for precise observation. The irradiated skins
were observed every other day from the seventh postirradiation day to the 35th post-irradiation day. An
area independent skin score (Table 1) modified from
Fowler's2) or Aizawa's3) one was used because the irradiated area was different among three groups. The
peak score during observation periods was used for the
analysis.
Table 1. Area independent skin score.
score
0.5
1.0
1.5

2.0
2.5
3.0
4.0
5.0

descriptions.minimal changes from normal
Igraying
slight reddening
definite reddening,
dry desquamation (+-)
Ino hair with slight atrophy
severe reddening or dry
desquamation (+) I atrophy
dry desquamation (++ )/scales
moist desquamation (+-)
moist desquamation (+)
moist desquamation (++)

Results
The peak skin reaction increased with dose until acertain skin reaction level. Then it saturated above acertain dose level. The saturation level of skin score
was different among each slit group: Score 4 for 25 mm
slit , score 3.5 for 15 mm slit, and score 2.5 for 5 mm
slit . These saturation levels were almost the same forthe two LET beams. Volume dependence was moreeminent in a higher dose region.
References

Fig. 1. Final collimator with a 5 mm slit made of copper.

Early skin reaction was observed to evaluate ra-1081) T. Kanai et al.: Proc. 2nd Workshop on Physicaland Biological Research with Heavy Ions. NIRS-M-90,
HIMAC-003, edited by K. Ando and T. Kanai, Natl.
Inst. of Radiol. Sci., Chiba, Japan, p. 1 (1992).
2) J. F. Fowler et al.: Int. J. Radiat. Biol. , 9, 241 (1965).
3) H. Aizawa: Nippon Acta Radiol., 33, 602 (1973).

5. Instrumentation

RIKEN Accel. Prog. Rep. 27 (1993)

Computing Environment around the Accelerator Facility
T. Ichihara, Y. Watanabe, and A. Yoshida
A general description of the data acquisition system at the RIKEN accelerator research facility can befound elsewhere.1) In this report, we will describe therecent improvement of the system.
(1) On-line data acquisition system
Currently, seven Micro VAX's are used for on-line
experiments at the RIKEN accelerator research facility. The node names and locations are as follows:
RIKMVl::RIKMV2::RIKMV3::RIKMV4::
SMART::
SMARTF::RIKLV2::

Micro VAX II (IF)Micro VAX II (B2F E3)
Micro VAX II (Linac)
Micro VAX II (B2F RIPS)VAX Station 3520 (B2F SMART)VAX Server 3300 (B2F SMART)VAX Station 3100 M76 (IF)Independent measurements and counter tests can be
performed without interference. The current version of
the data-taking program supports the CAMAC multicrate parallel-readout using multi-Jll's (starbursts) .
The throughput of the data acquisition is incr3asedby using these parallel readout features. Digital audio
tape (DAT) units of 2 GB capacity are used for the
standard on-line data recording.
(2) Off-line data processing system-l
The following VAX/VMS and Alpha/VMS work stations are available for the off-line data analysis and forgeneral purpose calculations.
RIKEN::RIKVAX::RIKVSO::RIKVS2::RIKVS3::
RIK835::RIKLVl::RIKAXl::RIKAX2::RIKAX3::RIKAX4::RIKAX5::RIKAX6::RIKAX7::RIKSNA::(virtual node name of the cluster)VAX-6610 (Central)
VAX Station 4000-60 [Ring IF]
VAX Station 4000-60 [Ring 2F]
VAX Station 4000-60 [Ring IF]
VAX Station 4000-60 [Radiation lab.]
VAX Station 3100 M76 [Linac Lab.]DEC 3000-400 (Ring IF)
DEC 3000-400 (Ring IF)
DEC 3000-400 (Ring 2F)
DEC 3000-300 (Linac lab.)
DEC 3000-300 (Atomic lab.)
DEC 3000-300 (Ring, nuclear theory)
DEC 3000-300 (Radiation lab.)
DECnet/SNA Gateway

Seven Open/VMS high-performance alpha work stations (RIKAXI-RIKAX7) have been newly installed
mainly for the off-line data analysis.
Theses computers are connected by LAVC (Local
Area VAX Clusters) via the ethernet. They are also

connected to the HEPnet (D ECnet) and TISN Internet(DECnet/IP) and reachable from all over the world.
(3) Off-line data processing system-2
Following FACOM main-frame computers have been
also used for the off-line data analysis.
FACOM M-380
FACOM M-1800/20(RIKEN ring cyclotron)(RIKEN computing center)

These two computers are connected by the Network
Job Entry (NE) and DSLINK via the ethernet. These
two computers are also connected to the DECnet/SNA
Gateway. Operation of the FACOM M-380 was terminated in the summer of 1993, because seven high performance work stations (Alpha/VMS) have been installed recently.
(4) Wide area computer network
The RIKEN accelerator research facility is connected to the world-wide network of HEPnet (High Energy Physics NETwork)/SPAN (Space Physics Analysis Network) as Area 40, which is a part of the DECnet Internet, and to the TISN internet (Todai International Science Network) which is a part of "The Internet" (NSFnet, ESnet, NSI, DDN etc.).
In order to support these wide area network connections, we are now supporting following 5 leased lines
at the accelerator research facility.
512 kbps
64 kbps
19.2 kbps
9.6 kbps
9.6 kbps

to University of Tokyo
to KEK, Tsukuba
to RIKEN Komagome
to Tokyo Institute of Technology
to NTT X.25 (DDX-80)

The leased line between RIKEN-Wako and KEK was
upgraded from 9.6 kbps to 64 kbps in August 1993.
(5) Address of the electric-mailThe address of the electric-mail for a general userof the RIKEN accelerator research facility is describedas follows, where the userid should be replaced by aproper name.
(HEPnet /D ECnet)
RIKEN:: USERID (or 41910:: USERID)(Internet /Bitnet)
USERID@RIKVAX.RIKEN.GO.JP

References
1) T. Ichihara et al.: IEEE Trans. on Nucl. Sci., 36, 1628
(1989) .

109

RIKEN Accel. Prog. Rep. 27 (1993)

A GAL16V8A Programming Equipment
J. Fujita
A programmable logic device (PLD) is a newlydeveloped small scale gate array whose internal functions are designed and programmed by the users. The
PLD can replace more than 90% of standard TTL
parts. They reduce the number of IC packages used
on a circuit board, and reduce the board space andthe number of boards. This results in a lower systemcost. Reduction of the number of packages reduces theinterconnections between the packages which are theleast reliable portions of a digital system, and therefore improves the reliability.
A generic array logic 16V8A (GAL16V8A) is one ofmany PLDs and is produced by LATTICE Semiconductor corporation. It is electrically erasable and 100
erase/write cycles are guaranteed. I)
The 16V8A has 36 unique row addresses accessibleby the users. Each of 32 rows addressed from 0 to 31
contains 64 bits of input term data where the custom
AND array pattern is programmed. The outputs of
the AND array are fed into an output logic macrocell(OLMC) , where each output can be individually set
to active high or active low state, with either combinational or registered configurations. A common Output Enable (OE) can be connected to all outputs, orseparate inputs or product terms can be used to provide individual output enable controls. The row withaddress 60 contains 82 bits of data which specify thearchitecture and output polarity for programming the
OLMC. The row with address 63 is addressed to erase
the bulk of the device and reset it to a generic state.
We have made and tested a programming equipment for GAL16V8A. The equipment consists of a
PC-9801 personal computer, a DIO-3298BPC parallel input/output interface board on the I/O slot of thecomputer, and a programming circuit board with a 20pins ZIF socket for inserting 16V8A. The programmingboard is shown in Fig. 1. The pins on the left end are
directly connected to the parallel I/O board througha 50-pins flat cable of 20 cm long. A bit pattern mentioned above is written with an usual text editor on
PC-9801 in a data format which is agreed by the Joint
Electron Device Engineering Council (JEDEC). Eachterm point is expressed by '1' (fused) or '0' (not fused)in this JEDEC format.
The device is programmed in the following procedure. STR pin 11 is set to logically high, V cc pin 20 isdriven to 5.25 V, and Edit pin 2 is driven to 15.0 V. A
row address number is selected by pins RAGO-RAG5
and the bit data to be programmed on the row are
shifted into a register through the serial data input

110·24.0V· 24.0V

44 -----r:-;-142 ---------t---J

38 ---------------~==============~~ EDIT18~~ - - - - - - - - - - - - - - -- - - ----"-1
4 ::~~
26: RAG3
7 RAG428

24

8 RAGS

34
36

SC LK
9 SD IN '10 GNDs~~:etSDOUT 12STR II

40 -------------------------------~

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

Fig. 1. A GAL16V8A programming board .

(SDIN) pin 9 with synchronous clock pulses on SCLK
pin 8. Program/Verify (P IV) pin 19 selects between
program and verify modes. When the P /V is set tohigh, the device enters the program mode. The datain the shift register are fused on the gate array when
STR is brought to low for 10 msec. The device enters
the verify mode when the P /V is set to low and STR
is negated for 5 microsec. The fused data are shiftedout from the serial data output (SDOUT) pin 12 withclock pulses on the SCLK. These program and verify
steps are repeated for all necessary rows.
The program is developed in language C, except forthe part written in an assembler to obtain a correct
pulse width of 10 msec for STR.
An address decoder circuit shown in Fig. 2 is programmed by this equipment and expected functions
are obtained on each pin.

AI9

Inl

vee

AI8

In2

InlS

AI7

In3

Inl4

AI6

In4

Out3

AIS

InS

GAL 16V8A Out2

In6

Outl

AI3

In7

In1)

AI2

In8

Inl2

All

In9

Inll

GNO

InlO

10

19
18

Vee
AS
A6

17
OOOOO-OFFFF
16

AI4

GNO

2q

IS

C00 40-C007FCOOOO-COO I F
A7

13
12
II

A8
A9
AIO

Fig. 2. An address decoder programmed in GAL16V8A.

References
1) GAL16V8 Data Sheet, LATTICE Semiconductor Corp.

RIKEN Accel. Prog. Rep. 27 (1993)

In-beam Mossbauer Spectroscopy in RILAC (1)Y. Kobayashi, Y. Yoshida,* H. HaBlein,* S. Nasu,** and F. Ambe
Implantation technique has been one of very powerful tools for materials characterization in detecting the probes in substances. This technique coupledwith nuclear methods, like NMR, PAC, and M6ssbauer
spectroscopy provides important information for thephysicochemical properties and complements the materials characterization. Particularly, implantation
studies with M6ssbauer spectroscopy have been carried out since 1965. A few years later an excellent
method was developed with the evolution of accelerator performance. 1,2) This is the M6ssbauer spectroscopy with the Coulomb excitation and recoil implantation by using time bunched beams from accelerators and it consists of the following three steps: (1) excitation of the 14.4 keV 57Fe nuclear level (M6ssbauer
level) in the target (57 Fe foil) via the Coulomb interaction with a pulsed heavy-ion beam (40 Ar , E = 110
MeV); (2) ejection of 57Fe atoms and recoil implantation into specimens; (3) measurement of a M6ssbauer
spectrum within 30 to 400 ns after implantation withuse of parallel-plate avalanche counters, repeated after
every beam burst. The in-beam M6ssbauer experimental setup by using a heavy-ion beam (Ar- or Xebeams) at RILAC is shown in Fig. 1. 3 ) It is a special
version of M6ssbauer spectroscopy, suitable to study
local features of single probe atoms in host matrices.
Via the hyperfine interaction s-electron densities, electric field gradients, and hyperfine magnetic fields canbe measured. Such information can be obtained on
an atomic level. The method of in-beam M6ssbauer
spectroscopy has been developed mainly at two accelerators, VICKSI in Hahn-Meitner-Institut-Berlin and
UNILAC in GSI. Y. Yoshida, R. Sielemann and theirco-workers have investigated the fast diffusion of Fe
atoms in metals by means of the in-beam M6ssbauer
technique. 4 ,5) However, only a few applications to hostsubstances except metals seem to have been reported
until now.
In the field of material science, the "in-beam
M6ssbauer method" possesses some characteristic advantages described as follows: (1) Single implanted
atoms can be virtually observed because there is norestriction of solubility limits for probes in any hostmatrices. (2) The probes are directly detected after
implantation within the lifetime of the M6ssbauer excited state (7 = 140 ns for 57Fe). Occupation probabilities for the lattice positions which are substitutional
and/or interstitial sites can be also determined. (3)Since pulsed beams are employed in such experiments,
it is also possible to study dynamic effects just after
the implantation by time differential coincidence.
A new scattering chamber is going to be constructed
and set at the beam-line D-1 in RILAC before February 1994. At the first beam time (March 1994), theperformance of in-beam M6ssbauer spectrometers will
be checked with indium metal as a host matrix. Another scattering chamber will also be made, allowing
coincident experiments involving a pulsed laser to create or anneal metastable electronic states in correlation
to the recoil implantation in the systems of martensitic
transformation of NiTi alloys, solidified rare gases (Ar,Kr, and Xe) , and inorganic compounds showing spincrossover and mixed-valence phenomena. Such experiments promise an increasing insight into the dynamics
of out-of-equilibrium electronic systems on an atomic
level. For this purpose, the most valuable would bean upgrading of RILAC concerning the beam intensity and the time-bunched beams. Higher intensity
would allow us to routinely perform investigations in
the time differential mode. With the beam intensityand pulsed beams available at present such an experiment seems impossible. The first step toward the development of such coincidence experiments could however be expected within the nearest future.
References
1) G. D. Sporouse and G. M. Kalvius: in M6ssbauer EffectMethodology, edited by r. J. Gruverman, Plenum Press,
New York, 4, 37 (1968).
2) F. E. Obenshain: ibid., p. 61.
3) S. Laubach, P. Schwalbach, M. Hartick, E. Kankeleit, B.
Keck, and R. Sielemann: Hyp. Int., 53, 75 (1990).
4) M. Menningen, R. Sielemann, G. Vogl, Y. Yoshida, K.
Bonde-Nielsen, and G. Weyer: Europhys. Lett., 3, 927

Fig. 1. The apparatus of the in-beam M6ssbauer experiment with the Coulomb excitation and recoil implantation.

*(1987).
5) P. Schwalbach, S. Laubach, M. Hartick, E. Kankeleit,
B. Keck, M. Menningen, and R. Sielemann: Phys. Rev.
Lett., 64, 1274 (1990).

Shizuoka Institute of Science and Technology** Faculty of Engineering Science, Osaka Univ.
111

RIKEN Accel. Prog. Rep. 27 (1993)

Development of Low Energy Unstable Nuclear
Beam Channel "SLOW"
T. Matsuzaki , R. Kadono, K. Ishida, A. Matsushita, 1. Watanabe, and K. Nagamine
beam
channelA
low-energy
radioisotope"SLOW" has been developed at RIKEN Ring Cyclotron. The SLOW beam line is not only for the
study of emission mechanisms of various low-energy
radioactive as well as stable ions from a characterized
surface of the primary target, but also for the generation of useful radioactive ion beams for surface-physics
studies of the secondary target. The detailed design,
construction and performance are described in Ref. 1.
The development works of the beam line has been
done to improve the vacuum, to decrease the background signals to a multi-channel plate (MCP) placedat the focusing point and to improve the mass resolution.
For the vacuum improvement, sheets of beryllium
foil of 50 /-Lm were placed at the entrance and exit ofprimary beam line connected to the SLOW beam line.
The beryllium foil separates the vacuum spaces andavoids intruding impurity components from the beam
dump line. In addition, an ion pump has been installed
to improve the vacuum around the target.
The background to MCP during beam-on to the target originates from the beam dump, target itself anda switching magnet in the E7 experimental room. A
radiation shield has been built around the downstream
end of the SLOW beam line to reduce the backgroundto MCP. The shield is composed of lead blocks andparaffin blocks with admixture of 10% boric acid. The
primary beam dump line has been also redesigned andinstalled, which has a larger diameter to avoid the primary beam hitting the beam duct wall. The primarybeam stops in a carbon cylinder enclosed by an evacuated stainless steel can and the produced outgas does
not flow into the beam line vacuum. The backgroundhas been reduced to one seventh of the previous value
after the above works.
After installation of new high-voltage power supplies
for electric quadrupole lenses, the beam line tuning

112

work has been performed.
For this purpose, anion-source system has been newly designed and constructed, and the mass spectra were observed for ionsfrom air, argon and xenon gases. Alkaline ions generated from a hot tungsten-target surface were also used,
where the alkaline atoms were contained in the target
as impurities. To improve the mass resolution, two setsof slits are placed in the line; an adjustable four-jaw
slit at the first focusing position (F1) and a fixed twojaw slit just in front of MCP at the second focusing
position (F2) , see Ref. 1. A typical mass spectrum forxenon ions is shown in Fig. 1 and the mass resolution(m/ Llm) is obtained to be about 550 in the mass region of 130- 140, where the widths of F1 and F2 slits
are 2 mm and 1 mm, respectively.

125-:::) 100

ci
'0
OJ

75

>-

50
25

655

660

665

670

675

680

685

690

695

700

ChannelFig. 1. A typical mass spectrum for xenon ions.

References
1) T. Matsuzaki, R. Kadono, K. Ishida, A. Matsushita,
and K. Nagamine: NucZ. Instrum. Methods Phys. Res.,
B70, 101 (1992).

RIKEN Accel. Prog. Rep. 27 (1993)

New Detector System for the First Focal Plane of SMART
H. Okamura, S. Ishida, N. Sakamoto, H. Otsu, T. Uesaka, T. Wakasa, H. Sakai, T. Ichihara,
T. Niizeki, K. Katoh, T. Yamamoto, T. Yamashita, Y. Hara, and H. Ohnuma
The first focal plane (FP -1) of the SMART spectrograph is primarily used to measure the (d, 2He) charge
exchange reaction. I) The 2He is efficiently measured
by the coincidence detection of two protons emitted toclose geometries. The large angular and momentum
acceptance of FP-1, combined with the medium energy deuteron beam from the RIKEN Ring Cyclotron,
greatly enhances the detection efficiency of the 2He.
The previous detector system, however, was inefficient
in resolving trajectories of two protons since it gave information only on X and Y coordinates. 2) It also had aproblem in the single-particle detection efficiency due
to the lack of redundancy.
A new detector system has been constructed aiming ·for the 2He detection with higher efficiency and better resolutions. It consists of two sets of multi-wiredrift chambers (MWDC) and two layers of plasticscintillator hodoscope. They are contained in a detector box which is filled with He gas to reduce themultiple scattering.
Each MWDC has six planes, X-X'-U-U'-V-V', consisting of cells 20 mm wide by 16 mm thick. The
X', U', and V' planes are offset by 1/4 cell with respect to the X, U, and V planes, respectively, toresolve left-right ambiguities. The U-U' and V-V'
wires are oriented at +36.87° and -36.87°, respectively. The anode wires are 30 {Lm gold-plated tungsten and the field-shaping wires are 80 {Lm gold-plated
molybdenum. The cathode planes are 50 {Lm goldplated molybdenum wires spaced by 5 mm and areshared by neighboring anode planes. Each wire is heldin place by delrin feedthroughs that are mounted inprecisely drilled holes in an aluminum frame with asize of 174w x 64 H x 25 D cm3 . The sensitive area is
112 w x 40H cm2 .
We employed the Ne + C 2H6 (20:80) drift chamber
gas as a compromise between the requirement to reduce the multiple scattering and the reasonably large
signal. 3) The MWDCs are operated at -2.7 and -3.1
kV on the cathode and field-shaping wires, respectively, and the single-hit efficiency more than 99% is
obtained.
Each layer of hodoscope consists of 16 plastic scintillators with a size of 8.5 w x 40H X 0.5 t cm3 . Neighboring
scintillators overlap by 5 mm. Two hodoscopes are offset by 4 cm to keep the effective cell size reasonably
small. The 2He event trigger is made by requiring that
there are at least two scintillators hit in both of thehodoscopes. It should be noted that those scintillators
can be neighboring ones. This trigger condition allows
a simple electronics, the reasonably high efficiency at
small ~p relative energies, and clean 2He events, atthe same time.
Currently the energy resolution of 700 ke V is routinely observed in the (d,2He) reaction measurement.
Further improvement is expected by optimizing the optics properties, for example, by making the fields of
PQ1 and PQ2 stronger. The study of this new optics
is in progress.
References
1) H. Ohnuma et al.: Phys. Rev., C47, 648 (1993).
2) H. Okamura et al.: RIKEN Accel. Prag. Rep., 25, 128(1991) .
3) A. C. Betker et al.: Nucl. Instrum. Methods Phys. Res.,
294, 549 (1990).

113

RIKEN Accel. Prog. Rep. 27 (1993)

Measurement of the Fusion Cross Section of 27 Al + 197 Au Using
MWPC and Multi-target System
A. Yoshida, T. Fukuda, T. Sekine, Y. Watanabe, K. Kimura, Y. Mizoi, M. Tanikawa, H. Sakurai,
Y. Watanabe, H. Kobinata, Y. Pu, C. Signorini, G. Liu, and M. Ishihara
A system was designed to measure efficiently thefusion-fission cross section of neutron rich unstable nuclei. To gain a reaction yield, we used a multi-target
system comprised of a stack of thin Au foil, and fission fragments were measured by two sets of MultiWire Proportional Chamber(MWPC) positioned bothat left and right side of the targets. The first experiment using an unstable beam 29AI was reported lastyear and the schematic view of this system has beenshown. I) In order to obtain a better knowledge of thedetector performance, an experiment was performedby using a stable 27AI beam with enough intensity andmonochromatic energy.
The experiment was done at E7 hall by using a direct
beam from AVF Cyclotron. The 6.5 MeV lu 27AI beam,with intensity of 107 cps maximum, was bombarded toa stack of 20 thin Au targets with thickness of rv 140
J.Lg/cm 2 on an average. Those targets were supported
by rv80 J.Lg/cm 2 Mylar backing foil and were locatedin the MWPC filled with 10 mbar iso-butane plus 40
mbar He gas. A Micro Channel Plate detector (MCP)
and an elastic scattering beam monitor were locatedat the entrance of the chamber to measure the beam
current. The energy loss and the transmission of the
27Al beam passing through each target were precisely
measured by a Si detector. The transmission of thebeam until the last 20th target was 93% and the total energy loss was 60 MeV. The energy deposits ofthe fission fragments in a wire plane vs. their ejected
angles are shown in Fig. 1. The energy deposits offission fragments were in good agreement with thoseof the 252Cf fission source, and were sufficiently larger
than those of elastically scattered particles, so that thefission was clearly separated from other backgrounds.
4-plane coincidence and the selections of the opening angle (155- 180 deg. in labo.system) were used
to get further reduction of the bakground. The efficiency of the detector was obtained by the simulation,
which takes into account the angular distribution of
the fusion-fission and the detector geometry.
We got an excitation function of the fusion cross section as shown in Fig. 2. The X-error bars indicate theevaluated energy spread of the 27AI beam on each Au
target and V-error bars include only statistical errors.
The experimental data show a good agreement withthe theoretical calculation by Stelson. 2)

1000

(mb)

100

+

10

Bt : barrier threshould+

Bm : mean barrier

130

140

Ecm (MeV]

Fig. 2. The energy dependence of 27Al+197Au fusionfission cross section. Each data point corresponds toone of the stacked Au target . The solid line indicates
the theoretical calculation based on Stelson model.

From this result, we believe that our system has
good capability of measuring the excitation functionof the fusion-fission cross section until the sub-barrier
region. We are planning to measure the fusion crosssection of 29AI and more neutron rich beams by using
this system.
Emitted angle from a target (deg)Fig. 1. The energy deposits of the fission fragments in awire plane vs. their ejected angles from the Au target.
Fission fragments show a larger energy deposit thanother elastically scattered particles.

114

References
1) A . Yoshida et al.: RIKEN Accel. Prog. Rep., 26, 20(1992).
2) P . H. Stelson: Phys. Lett. , B205, 190 (1988).

RIKEN Accel. Prog. Rep. 21 (1993)

First Laser-rf Double Resonance Spectroscopy ofRefractory Elements
M. Wakasugi, W. Jin, T. Inamura, T. Murayama, H. Katsuragawa,T. Ishizuka, M. Koizumi,* and 1. Sugai
A laser-rf double resonance (LRDR) spectroscopy
technique is powerful for precise measurements of hyperfine structure (HFS) because the high sensitivity oflaser-induced fluorescence detection is coupled to thehigh precision of radio-frequency spectroscopy technique in LRDR. This technique has been firstly applied to study molecular structure and HFS in atoms
eighteen years ago.1 ,2) A lot of information about
atomic structure and nuclear properties have been deduced from experimental data measured by means of
LRDR.3) This technique, however, has never been applied to refractory elements because it is hard to pro- ·duce the atomic beam.
We have constructed a high-resolution atomic-beamlaser spectroscopy system for refractory elements using
an argon-ion sputtering atomic-beam source,4) and introduced a laser-rf double resonance technique to thesystem. We have succeeded in the precise measurements of the hyperfine structures of the ground state
4F3/2 in 181TaI and a low lying metastable state 5D 2
in 183WI , which are typical refractory elements, forthe first time using the LRDR technique.
An intense atomic beam of refractory elements wasproduced with argon-ion sputtering; we can get a collimated atomic beam of 10 10 atoms/so Two laser beams
were crossed with the atomic beam perpendicularly.
One was used as a pump laser and the other a probe
laser. The pump laser was reflected to the opposite
direction with a cubic mirror to increase the opticalpumping effect. Fluorescence induced by the probe
laser was detected with a single-photon counting photomultiplier. An rffield was produced with 2.5-cm longwire (rf loop) parallel to the atomic beam between twolasers; a synthesizer coupled to a power amplifier wasused as an rf source; and the applied rf power was typically 30 m W at the terminal connected to the wire.
To reduce the stray magnetic field in the rf region,
Helmholtz coils were used in three dimensions.
First, we carried out laser-induced fluorescence spectroscopy with the 551.5-nm transition from the 5D 2
state of the 5d 46s 2 configuration to the 7Dl state of
5d46s6p configuration in 183W1. Three hyperfine transitions were observed in this spectrum because boththe upper and the lower states were split into two hyperfine levels. When the laser frequency was fixed at
one of the transitions, the fluorescence intensity was
reduced to 10% of that without pump laser. We could
clearly measure the change of the fluorescence intensity as a function of rf frequency. Figure 1 shows the*rf resonance spectrum, and the center of the resonancefrequency corresponds to the hyperfine splitting in the
5D 2 state.
1500 , - - - - - - - - - - - .

•
}:
-.

• •

~ \

•

I

•

J

,••

'";,

o~~~~--~----~

300

700
1100
1500
RF frequency (+ 139800 kHz)

Fig. 1. RF resonance spectrum of 5D 2 state in 183W1.

The hyperfine splitting in the 5D 2 state was determined to be 140670.3(20) kHz by making a leastsquares fit to the experimental line shape with a
Lorentzian function. The magnetic dipole hyperfine
constant A was derived to be 56268.1(8) kHz. Thisvalue agrees with the previous one measured by meansof atomic-beam magnetic resonance,5) and the accuracy was by one order improved compared with it. The
precise values of the hyperfine splittings of the 4F3/2
state in 181TaI were also determined with accuracy of
2 ppm.
In this experiment, we found that the heavy-ion
sputtering is exceedingly useful for precise measurement of hyperfine structure of refractory elements.

References
1) S. D. Rosner, R. A. Holt, and T. D. Gaily: Phys. Rev.
Lett., 35, 785 (1975).
2) W. Ertmer and B. Hofer: Z. Phys., A216, 9 (1976).
3) W. J. Childs: Phys. Rep., 211, 113 (1992).
4) M . Wakasugi, W. G. Jin, T. T. Inamura, T. Murayama,
T. Wakui, T. Kashiwabara, H. Katsuragawa, T. Ariga,
T. Ishizuka, M. Koizumi, and 1. Sigai: Rev. Sci. Instrum., 64, 3487 (1993).
5) S. Biittgenbach, R. Dicke, and F~ Traber: Phys. Rev.,
A19, 1383 (1977).

Jpn. Atomic Energy Res. lnst.

115

RIKEN Accel. Prog. Rep. 27 (1993)

Measurement of Attenuation Length of Scintillation Photons in
Liquid Xenon Due to Heavy Ions
K. Masuda, N. Ishida, K. Kuwahara, H. Okada, T. Komiyama, K. Hasuike,
M. Suzuki, M. Kase, T. Takahashi, J. Kikuchi, and T. Doke
Liquid xenon has very good properties not only
as ionization detectors, but also as scintillation
detectors!) because of its la~ge scintillation yield (4 x
107 photons/GeV) and its fast scintillation decay time
(5 ns and 20 ns). In good scintillators, the emitted
photons should travel in the scintillator without attenuation and be detected by photo-detectors. In thisexperiment, the attenuation length of photons emitted
in liquid xenon has been measured using a improved
liquid xenon scintillation chamber.
Figure 1 shows a schematic diagram around photomultiplier which was newly installed. The whole chamber schematic is shown elsewhere. 2 ) There are six beam
windows that allow heavy ions to enter the inner chamber and excite liquid xenon. Each window is separated
by 10 em to each other. A cylindrical anti-reflector was
installed in the chamber. This reflector was carefully
designed (see the circle in Fig. 1) because only a few
percent reflection at the wall would change the result
remarkably. Therefore, a part of photons, corresponding to the solid angle for the Pyrex glass, should be observed. The wave length of emitted photons is shiftedby a thin sodium salicylate layer deposited on the
Pyrex glass and observed by photo-multiplier (Hamamatsu R329). The inner chamber containing liquid
xenon was thermally insulated and cooled by dry ice

blocks put into ethyl alcohol (see Fig. 1 of Ref. 2). The
space between the inner and outer chamber (see Fig. 1)
was evacuated by a turbo molecular pump (less than1 x 10- 6 Torr), and the inner chamber wrapped byaluminized mylar. The operating temperature and pressure was precisely kept at the temperature of -77°C
and at the pressure of 4.8 atm during the experiment.
Liquid xenon was purified three times by molecularsieves and GAS CLEAN,3) and reserved in the sampling cylinders before experiment.
Figure 2 shows the experimental result. The lightyields per solid angle were normalized at the distanceof 137 mm that corresponds to the nearest beam window to the Pyrex glass. If scintillation photons travel
without any loss, this value should be unity over thewhole distance. The exponential fitting in Fig. 2 showsthat the attenuation length is 304 mm. This result is
consistent with experiments by other authors. 4 ,5) Thisvalue seems to be long enough when scintillation lightis used for a timing signal of time projection chamber,but too short for a large scale calorimeter.
1.2

c

~

\ r-6a'~ ar~ n~rm~lIz~d ~I d l= ,137 i(m~)_\ 1 ~-III I

-I--

1.0

1

~

.,.

.!! 0.8
c

~

'\

i
!

0 .6

"0

"a

.1 . 3&. (~mi-. -.

'\.

!

""'-

III

..

i

I r-,.

0(

0 .4

I

""

'I'--,~ 0.2.c........ ...........

. .,.
:::i

0.0

o

100

200

300

400

500

800

-700

Distance(mm)Outer·Chamber

Fig. 2. The light yields per solid angle against the distance
between the beam window and the Pyrex glass. Data
are normalized at the distance of 137 mm.

References

Pyrex Glass

Fig. 1. A schematic diagram around the photo-multiplierand a magnified figure of the anti-reflector.

1161) T. Doke: Portugal Phys., 12, 9 (1981).
2) T. Doke et al.: RIKEN Aceel. Prog. Rep., 25 , 140 (1991).
3) Nikka Seiko Co., Ltd. GAS CLEAN GC-RX.
4) A. Braem et al.: Nucl. Instrum. Methods Phys. Res. ,A326, 325 (1993).
5) M. Minerskjold et al.: ibid., to be published.

RIKEN Accel. Prog. Rep. 27 (1993)

Measurement of Response Functions of Organic Liquid Scintillator
for Neutrons up to 133 MeV
T. Nakamura, N. Nakao, M. Takada, T. Shibata, Y. Uwamino, K. Shin,*N. Nakanishi, S. Fujita, S. Nakajima, T. Ichihara, and T. Inamura
We have measured the response functions of a 12.7cm-diameter by 12.7-cm-long BC501A organic liquid
scintillator (BICRON Co.Ltd) for neutrons of energy
up to about 133 MeV with the TOF method using
RIKEN Ring Cyclotron.
Ht -ions accelerated to 135 MeV lu were injected
to a 5 mm-thick natural Li target (1.25 MeV loss)
and a 7 cm-thick 9Be target with 2 cm-thick graphite(full stop). Semi-monoenergetic neutrons and whitespectral neutrons were generated from the Li target
and the 9Be + C target, respectively. In both cases,
neutrons were generated at 0 degree to the beam axis
and charged particles which penetrated through thetarget were swept out by the clearing magnet. The detector was placed at 13.47 m away from the target in
the E4 beam course. In order to measure the response
functions for neutrons of energy as lower as possible,
pulsed beam was thinned out to 40 f-lsec pulsed beaminterval with the beam chopper only in the 9Be + Crun, where the pile up of low energy neutrons « 50
MeV) to high energy neutrons (> 50 MeV) was reduced to 1 to 2%. The neutron flight time, the pulse
height and rise time of the detector light outputs were
measured in the list mode and the list data was stored
by a CAMAC data taking system.
The time resolution in this experiment was about
1.53 nsec which resulted in about 5. 7 MeV energy resolution for the 133 MeV neutron energy. After eliminating ')'-ray pulses from the rise time distribution,
we have obtained the neutron response functions forenergy range between 9 MeV and 133 MeV. Figure 1
shows the response functions for 74-78 MeV and 120125 MeV neutron energy range as an example.
The measured response functions were comparedwith the response functions calculated with the Monte
carlo codes, SCINFUL 1 ) and for neutrons up to 80
MeV. Some disagreements between measurement andcalculation can be seen except the upper edge of the
response functions, since the charged particle production reactions of 12C are not well estimated. The ab-*.....•..... Measured- - Calculated

20

40

60

80

Light output [Co-unit]

Fig. 1. Response functions of the scintillator.

solute values of the measured response functions wereobtained by normalizing them with respect to the calculated value around the upper edge of the response
function, which enabled us to get the detector efficiency. Figure 2 shows the neutron spectra of p-Li and
p-9Be + C reactions obtained with the help of thusobtained detector efficiency.

50

100

150

Neutron Energy [MeV]Fig. 2. Neutron spectra of 135 MeV p-Li and p-9Be + C.

References
1) J. K. Dickens: Computer in Phys., Nov./Dec., p. 62(1989).

Department of Nuclear Engineering, Kyoto University

117

RIKEN Accel. Prog. Rep. 27 (1993)

Test of Inorganic Scintillators Using RIKEN Ring Cyclotron
K. Matsuzaki, T. Ichihara, Y. Saito, K. Suzuki, and T. Takahashi
We plan to study astronomical objects in theHard X/gamma-ray band (30 keV- 1 MeV) with a
new detector on board a satellite. Expected fluxin the hard X/gamma-ray region is low (10- 5 - 10- 6
photons/cm 2/s/keV) and thus we need a detector withhigh sensitivity.
Sensitivity of the detector is limited by the background counts. In order to achieve the high sensitivity,
we have developed a well-type phoswich counter. 1,2)
The counter features a very tight active shield thatsurrounds a small detection part. A collimator and ashield of the counter are made of BGO : Bi4Ge3012
scintillators. The candidate for detection part of thephoswich counter is an inorganic scintillator YAP :YAI0 3(Ce) or GSO : Gd 2 SiOs(Ce) which possesses a
shorter decay time than BGO (see Table 1).
Table 1. Characteristics of scintillators.

Decay time( ns)
Effective atomic number
Density(g/ cm 3 )Radiation length( cm)
Peak emission (nm)Light yield(NaI=100)
Index of refraction
Hygroscopic

NaI(TI) GSO BGO YAP
230
60
300
30
74
50
59
35
7.1
3.7
6.7
5.5
2.6
1.2
2.6
1.4
410
430
480
347
12
25
40
100
2.15 1.94
1.85
1.9
Yes
None None None

Inorganic scintillators (e.g. NaI, CsI) have been usedin space to date but the activity induced by the cosmic ray has been limiting the detectors' sensitivity.3)
We carried out this experiment to select a scintillator
which would be least activated by the cosmic ray. We
examined three scintillators, YAP, GSO and NaI(Tl).
We used the N aI as a standard scintillator in our study.
In the orbital environment the typical energy of proton after passing through a BGO shield is expected
to be rv 100 MeV. Thus we placed the scintillators in

118

135 MeV proton beam line of the Riken Ring Cyclotron. Beam was extracted through a 5cm acrylic
window and the energy of proton becomes rv100 MeV
by the energy loss in the window. The number of protons was counted with three plastic scintillators in coincidence. The beam intensity had been set extremely
low (rv 3 x 104 C / s / cm 2 ), so that scintillators could
count each proton. Protons corresponding to three
year's exposure in the orbit (about 3 x 108 protons)
passed through each scintillator.
We have been measuring gamma-ray emitted fromradio-isotopes produced in each scintillator. The level
we are measuring is far below the room background,
and we use a low background cave made of thick Pb
and Cu for the measurement. Since the phoswich
counter can reduce compton-scattered events in whichsome fraction of energy is deposited in the active
shields, identification of the radio-isotope is important
rather than net continuum level.
From the measurements of initial three months, the
NaI shows many prominent peaks with lifetimes from
one to a few days in the energy range 100- 400 keV.
Two lines with a longer decay time at around 60 ke V
and 100 ke V still remain in the spectrum. The GSO
also shows many peaks but the magnitudes are lower
than those of the N aI by an order of magnitude. The
YAP shows some peaks at around 45, 400, and 500
ke V. The magnitudes of these peaks are of the sameorder as these of the GSO. However, the feature that nopeaks are shown in the energy range 50- 350 ke V is very
promising for our hard X-ray detector. If GSO or YAP
is used, the background rate is estimated to be lower
than the previous mission with an NaI scintillator.
References
1) T. Kamae et al.: IEEE Trans. Nucl. Sci., 40-2, 204(1993).
2) T. Takahashi et al.: ibid., 40-4, 890 (1993).
3) A. C. Rester et al.: AlP Con!. Proc., 186, 223 (1987).

RIKEN Accel. Prog. Rep. 27 (1993)

A New Method of Pulse Shape Discrimination for
BaF 2 Scintillators
Y. Yanagisawa, H. Murakami, S. Moriya, T. Motobayashi, K. Furutaka, and Y. Futami
The pulse-shape analysis technique has been
widely applied to particle-/, discrimination for BaF 2
scintillators. 1 ,2) The light output of BaF 2 has two components, the fast one with 0.6 ns decay constant andslow one with about 0.611,8 (Fig. 1). This allows the discrimination, because their relative intensities dependon the type of radiation detected. Usually the fastcomponent is measured by a charge sensitive ADC witha narrow gate of several tens nanosecond duration, andis compared with the total light output measured witha wide gate of about 2J-ls.
We developed a new method based on the RC(CR)4
shaping with a short time constant (2.1 ns) to pickup the negative fast component. This method has anadvantage in experiments using many scintillators, because the ADC's can be operated with a wide gatecommon to all detectors. This makes the electronics
system much simpler and cheeper than in the usual
method, where the gate timing has to be adjusted foreach detector to account for the different arrival timeof the particle detected.
The performance of the present method was tested
by using a shaping amplifier with about 2 ns shaping
time constant. The shaping amplifier was composedof a hybrid IC (MA405) and a base time clamping circuit. The response of the amplifier to a BaF 2 signal isshown in Figs. 1 and 2. These figures demonstrate thatthe fast component was picked up with the amplifier.
Eight amplifiers were set in a NIM one-span module
to match experiments with many BaF 2 scintillators.
BaF 2 scintillators were irradiated with various particles, and a good particle separation was obtained. The
present method was successfully applied to a phoswich
detector consisting of plastic and BaF 2 scintillators.

:--),rrv "'
~

r'"

(
Chl
<t

r .omro

M

rom

Chl

[\. -Y5mv

40nS

Fig. 2. The response of the amplifier to a BaF 2 signal(Fig. 1) .

ChlrOomr)

M

rons

Chl

f\-

-s"t 5mv

lOOnS

Fig. 1. The output signal of a BaF 2 scintillator with 137 Cs.

References
1) K. Wisshak and F. Kappeler: Nucl. Instrum. Methods
Phys. Res., A227, 91 (1984).
2) S. Kubota et al.: ibid., A242, 291 (1986).

119

RIKEN Accel. Prog. Rep. 27 (1993)

Development of Radiation Monitor in Space
T. Imai, H. Kato, and T. Kohno
Protons, electrons and alpha particles (we call themlight particles hereafter) are major components of thespace radiation environment. During recent several
years we have developed a cosmic ray heavy ion telescope for the satellite observation. 1 ) The main targetof this telescope is limited within the elemental range
from Li to Fe because of its large dynamic range ofpulse height information to be dealt with. But theflux data of the light particles in space are also necessary because they can be a very important referencesuch as solar flare events. Meanwhile, for identificationof the light particles, we do not need a high resolution
technique such as position sensitive detectors which
are necessary for the heavy particle identification. Furthermore, since the flux of light particles is much higher
than that of heavy particles, we can use relatively small
detectors to get sufficient statistics. Therefore the observations of light particles should be done by a different telescope which is simpler than that for heavy
particles. According to above consequence, we have developed another telescope for the observation of lightparticles. And these two telescopes are planned to belaunched aboard the same satellite, ETS-VI (the sixth
Engineering Test Satellite). This telescope is called
DOM (DOse Monitor), althogh it observes not 'dose'
but energy spectra of light particles. The reason forthis name comes from the applicational point of viewthat the 'dose' in space is mainly caused by electrons,
protons and alphas.
As shown in Fig. 1, the telescope consists of sevensilicon solid state detectors. The first two and the last
one detectors are PIN type photo-diodes with a thickness of 0.2 mm and an effective area of 10 mm x 10 mm.
The other four detectors are lithium drifted type silicon detectors with a thickness of 3 mm and an effective diameter of 10 mm. The first two detectors (PIN1,
PIN2) are used for coincidence measurement and PIN1
is used as a D..E detector. The total energy E is defined as the sum of all detectors except anti-detector(PIN3). If we consider a quantity of!:J..E x (E + k x !:J..E) ,this value becomes nearly constant against energy andshows different values depending on the particle mass.
(The value k is adjusted by experimental results.) According to this principle and by using combination ofsum and multiplication circuits, we can identify electrons, protons, alphas and particles heavier than alphas. The energy regions to be observed for each particle are 0.5-5 MeV for electrons, 7- 45 MeV for protons,
28- 180 MeV for alphas and 80- 330 MeV for particles
heavier than alphas. All these energy regions are divided into 16 channels and the count number of allchannels is telemetered to the ground in every 64 seconds.
In order to check the characteristics of each detector, we performed accelerator measurements using
95 MeV lu 40 Ar beam from RIKEN Ring Cyclotron.
Seven samples of lithium drifted detectors were irradiated with a direct beam guided to the atmospherethrough a myler film. In order to check the energy losschange in each detector five of them were also irradiated with a beam passed through a 2 mm aluminum
plate to degrade the beam energy. The measured peakenergies of each detector are shown in Table 1 in comparison with calculated values. The results show thetendency that the measured energies are 10% larger forthe direct beam and 5% less for the energy degraded
beam, respectively, than the calculated values. Since
we do not need so high accuracy for the particle separation as written above the obtained results given in
Table 1 are acceptable for practical use.
Table 1. Measured energy outputs of seven detector samples.
MeV

1
2
3
4

5
6
7

.obs/cal

noAl

Al2mm

no Al Al2mm

1889
1884
1908
1908
1921
1910
1915

2496
2502
2490
2477
2480

1.09
1.09
1.11
1.11
1.11
1.11
1.11

0.95
0.96
0.95
0.95
0.95

References
Fig. 1. Cross sectional view of detector assembly of DOM
telescope.

1201) T. Kohno et al.: l. Phys. Soc. lpn., 60, 3967 (1991).

RIKEN Accel. Prog. Rep. 27 (1993)

Segmented Germanium Detector
E. Ideguchi , Y. Gono, T . Morikawa, T. Kishida, and M. Ishihara
Gamma ray mesurements using heavy ion induced
react ions are often suffered from the Doppler effect.
This effect is especially serious when one uses, so
called, inverse reactions . The use of high-spin isomerbeams (HSIB) is one of such cases. High-spin isomers
to be used as secondary beams are those of N = 83 isotones, 144Pm, 145Sm , 147 Gd, and 148Tb. In these cases
the secondary target may be light elements. Then one
expects that recoil velocities of the reaction products
become to be as high as 0.10 of light velocity, which isabout a factor 3 larger than that of normal heavy ion
induced reactions.
To correct the energy shifts originating from theDoppler effect, it is neessary to detect ,-rays to get .
information of directions of emitted ,-rays and to set
each Ge detector having small solid angle. In order toachieve this aim, we designed a detector complex consisting of a segmented Ge and a cylindrical Ge counteras shown in Fig. 1. The segmented detector is a transmission type .6.E ,-ray counter. The cylindrical Ge
detects Compton scattered ,-rays from the segmented
Ge detector.

r- scm-+3.1cm-1
Fig. 1. The set-up of Ge detectors.

In order to estimate the performance of this detection system, we made simulation for the set-up of Ge
detectors as shown in Fig. 1. In order to get good position sensitivity and large efficiency, one needs to increase both the number of segments and the thicknessof the crystal. On' the other hand, cross talk events
increase with the thickness of the segmented detector.
So we chose the size of each segment as 10 x 10 mmwith 20 mm in thickness and the total number of segments as 25. The segmented Ge detector is used as ascatterer and gives directions of emitted , -rays. Thenthe energy information should be obtained by summing signals from two detectors. Since multiply hit
events in segmented Ge loose the direction information, only single hit events are taken. The resulting
sum energy spectrum for a 1.33 MeV ,-ray is shownin Fig. 2. Continuum part of the spectrum is much
reduced comparing with that of a spectrum taken bya single Ge detector.

Channel Number
Fig. 2. Calculated sum energy spectrum for a 1.33 MeV,-ray.

Figure 3 shows the total energy peak efficiency ofvarious combinations of Ge detectors obtained by using Monte Carlo simulation program. In the figure,abbreviations, Cyl(C), Seg(S), Clv, mean a normal
cylindrical Ge, a segmented Ge and a clover typedetector,l) respectively. The lowest efficiency curve,'lCylat25cm', corresponds to a case where one cylindrical Ge is placed at 25 cm from a target which has
the same solid angle as those of each segment placed
at 5 cm from a target. A case of 'lSeg1Cyl' , whichmeans one set of 25 segmented Ge is set at 5 cm froma target and one cylindrical Ge is set right back of
the segmented Ge, has about a factor 3 larger efficiency comparing with a single cylindrical Ge at 25cm. However, when one uses 1 segmented Ge with 7
cylindrical Ge's, ' lSeg7Cyl', one gets only 2.5 times
larger efficiency than 'lSeg1Cyl'. This means that thedead space between Ge detectors is too large. And
one can find that a single Ge at right back to the seg-==lO" ~~~§=~g@
--==
o

>-"
gCD ~\""T. - -- --" " 6""........

1Seg1Cyi
1Seg7Cyi
1Seg1Clv 1Seg4Clv -:2=
10 '2 Frl- ~- ~~'~"~;~~~--~. ~-~. - ~1C~YI~a~t2~5c~m~Wtu ...... ~~;-.............. .. ..

~.'~.~,..-."~~--..-...-.. ~
~.~
...~
....~
. .~. ..~...~".

- -0-.._ _ _ _ _ _ ....

W 1O. 3Et--~~~~~~~~~~~~
as
~
(5

I1

2

Energy (MeV)

Fig. 3. Calculated total energy peak efficiency of various
combinations of Ge detectors.
121mented Ge is far more effective comparing to the other6 cylindrical Ge's. A clover Ge has 4 Ge's in one cryostat so that the dead space between Ge detectors is
minimized. So the segmented Ge can be used mosteffectively by combining it with a clover Ge detector.
From our simulation for 'lSeglClv', we got as large
efficiency as 'lSeg7Cyl', as shown in Fig. 3.
Finally it may be worth while to point out that the122

continuum part of the spectrum in Fig. 2 arises fromthe ,,-rays escaped from the back detector. This canbe further reduced if one uses an anti-Compton shield
for the back detectors such as cylindrical Ge's or clover
Ge's.
References
1) J. Gerl and R. M. Lieder: EUROBALL III, p. 52 (1992) .

6. Material Analysis

RIKEN Accel. Prog. Rep. 27 (1993)

In-situ Analysis of Liquid Samples by PIXE
K. Maeda and J. Kawai
PIXE (particle induced X-ray emission) is an attractive tool to study the dynamic processes in liquid suchas diffusion and coagulation. PIXE analysis of liquidsamples is, in general, carried out using solid targets
prepared by preconcentration (e.g. evaporation of solvent) , and there is little information available as tothe direct analysis of liquid. We have examined appropriate experimental conditions and normalization
parameters for the quantitative analysis by direct (Le.
in-situ) observation of liquid.
Aqueous solutions of nitrates of Cu, Fe and Cr (tensto thousands ppm) and their mixture (Cu 100 ppm,
Fe 60 ppm) were used as model samples. Twenty ml
of a sample solution was put in a polycarbonate bottle with a 7.5 /Lm-thick Kapton window. Each bottle
was equipped with a Pt wire (0.5 mm in diameter)
probe for beam current monitoring. A He ion beam of
8.0 MeV and 3 mm in diameter accelerated by RILAC
was transported into air through a 6 /Lm-thick Al exit
window. The sample solution was irradiated with thebeam through the Kapton entrance window. Emitted
X-rays were analyzed by a Si(Li) semiconductor d2tector with 30 mm2 sensitive area. The distance between
the Al window and the Kapton window was 6 mm. After passing the 6 J.Lm AI, the 6 mm air gap and the 7.5
J.Lm Kapton, the energy of the He ions decreased by 2.0
MeV, giving an incident beam energy of 6.0 MeV atthe solution. The penetration depth of 6.0 MeV He inwater was 44 mg/ cm 2 .
As a normalization parameter, (1) the integrated
sample current (Le. accumulated charge (Q)) measured
through the Pt wire, (2) the background continuum intensity integrated from 10 to 15 keV, and (3) the Ar
Ka X-ray intensity from Ar in air were found to be
useful in the order of (1)- (3). We repeated the X-ray
measurement twice or more for each target sample, irradiating the He beam continuously. When the total
amount of accumulated charge throughout the experiment (denoted by 'total accumulated charge') did notexceed 1 /LC, good proportionality (standard deviation
S.D. = ±12% for parameter (1)) was obtained between
the CuKa intensity and the Cu concentration over therange of three orders (see Fig. 1). S.D. for parameters(2) and (3) were ±14% and ±15%, respectively. The
minimum detection limit for Cu for Q = 1 J.LC was 4ppm. The good proportionality was also obtained for
Cr. But the proportionality was broken for tens ppm
Fe solutions. Increasing the amount of incident beamis useless for improving the accuracy of analysis, since,

105 ..-----,---01 - - - , - - - - , . . - - - - . - - - - - - ,o CrX·ray counting during~ Fe L total accumulated• CuJ charge =0-1 IlC,o Cu- total accumulated
charge =1- 3 IlC.

-

-

. /
102 L__~/_---I.-:--....L.'_ _ _L__~IL___ __'__._J

101

102

103

104

Concentration (ppm)Fig. 1. Ka intensities of Cu, Fe and Cr normalized withthe accumulated charge (Q). The gradients of the dotted lines are 1, showing that the X-ray intensity ex: themetal element concentration. Q = 0.5-1 /-LC.

as seen from Fig. 2, the solute element tended to deposit on the Kapton window surface when the total
accumulated charge exceeded ",,2 J.LC. Bubbles due tobeam irradiation were not found when the total accumulated charge was kept less than ",,2 J.LC. From thisstudy, we conclude that direct observation of dynamic
phenomena in liquid phases by using PIXE is possible
under moderate beam irradiation.

Q --0----0- -

30000
20000

---u-

Cu 5880 ppm

10000

<5

0

::i.

p

Cu 645 ppm

~

6000

0

4000 G- - -o- __ -0-- _---0-

~

..s.
z;.

'in

0

.~
d

4000

::.::

---

2000

c

<l>

/

./
./

p

Cu 58.4 ppm

I

/

/

~

/

<.)

/

2000
4---q---.()--

00

2

-..-

./p
3

4

5

total accumulated charge (J.1C)

Fig. 2. Change of the Cu Ka intensity as a function of
the total accumulated charge. Q = 0.5- 1 /-LC.

123

RIKEN Accel. Prog. Rep. 27 (1993)

Hydrogen Depth Profile of AI-alloy Vacuum Chamber
Exposed to Synchrotron Radiation
K. Kanazawa, M. Yanokura, and M. Aratani
Neutral gas desorption due to synchrotron radiationis the main gas load for vacuum systems of electron
storage rings. The main desorbed gases are H 2 , COand CO 2 for typical vacuum chamber materials suchas aluminium, copper and stainless steel. The basic motive of this paper is to identify the gas source
through the quantitative measurement of surface hydrogen, carbon and oxygen for samples exposed to synchrotron radiation. In this paper, hydrogen near thesurface of aluminium is analysed by ERDA (Elastic
Recoil Detection Analysis)l) using RILAC. 2 ) Samples
were prepared from a quadrupole magnet chamber of
the TRISTAN accumulation ring which had been exposed to synchrotron radiation over 6 y (Fig. 1). The
vacuum chamber of the TRISTAN is made of specially
extruded aluminium of the type 6063 (ISO AIMgSi).
Every sample has a hydrogen concentrated layer
on its surface, whose number density is from 0.42 to
5.4 x 1016 atoms cm- 2 . The depth profile of hydrogenis shown in Fig. 2. Most of this hydrogen is considered
to be contained in a surface oxide layer of aluminium.
The surface irradiated directly with synchrotron radiation (sample 3-2) shows the least hydrogen content.
The exposure to synchrotron radiation is well memorized as the depletion of the number of surface hydrogen. This means that H2 desorption during exposure
to synchrotron radiation originates from the observedhydrogen concentration. The result is imporant to understand the mechanism of the desorption due to synchrotron radiation.

2

l

Q90

g 0..77~ 0.64..... 0..5 1

i

!

. \

2 -1

},

4-1

,

'\

~

§ 0..38
3-2
0..26
0..13
0.20.

ElGJGJ

-

/'

j\

1- 1

148
CHANNEL NUMBER

Fig. 2. Hydrogen depth profile of the first group of aluminium samples measured with detector-l with a 20 f.-£m
aluminium absorber. Vertical scale is linear. Energy islower toward the left. The peak corresponds to surfacehydrogen. Hydrogen in metal, whose energy is lower
than that of surface hydrogen, is hardly counted.

--H----

S1
~"

[J

~

,

Cross· sec tion of a quad rupole magnet
chamber of the TRISTAN accumulation

References

(" I

ring

1) H. Nagai, S. Hayashi, M. Aratani, T. Nozaki, M.
Yanokura, I. Kohno, O. Kuboi, and Y. Yatsurugi: Nucl.
Instrum. Methods Phys. Res., B28 , 59 (1987).
2) E. Ikezawa, Y. Miyazawa, M. Hemmi, M. Kase, Y .
Chiba, T. Chiba, T. Aihara, T. Ohki, and H. Hasebe:
Proc. 14th Symp. on ISIAT '91 , Tokyo, p. 151 (1991).

oFig. 1. The original location of samples in the quadrupole
magnet chamber. Samples 3-1, 3-2, and 3-3 are cut
from the area where the synchrotron light illuminateddirectly.

124~

RIKEN Accel. Prog. Rep. 27 (1993)

Simultaneous Depth Analysis of Deuterium and Helium in
He+ -implanted YIG Annealed in D2
K. Matsushita, T. Kikuchi,* K. Furuya, M. Yanokura, M. Aratani, and R. Imura**
Annealing of He+ -implanted magnetic bubble garnet films in a hydrogen atmosphere enhances the magnetic anisotropy field through the chemical effect ofdiffused hydrogen in the ion implanted lattice. 1) Re'cently, a photo-induced effect of ion-implanted YIG
films has been found by Tsuchiya et al. 2) To elucidate
both mechanisms, a study on the depth distributionchange of helium and hydrogen in the film during annealing procedure by elastic recoil detection analysis(ERDA) has been carried out. The condition of simultaneous depth analysis of hydrogen, deuterium and helium has been developed and the change of depth distribution of these elements through annealing has been ·analyzed.
Samples were prepared as follows: After the growthof 1.6 J-Lm thick Y3Fe5012 (YIG) films on both sidesof 2 inches thick Gd3Ga5012 (GGG) substrate by aconventional liquid phase epitaxial method, He+ ionswere implanted on one side of the film with a doseof 1.2 x 1016 ions/cm 2 at 90 KeV. Specimens were annealed at 320 ° C for 1 hr not in a hydrogen atmospherebut in a D2 atmosphere at 1 atm as a tracer.
The depth profiles of hydrogen, deuterium and helium in this sample were measured simultaneously by
ERDA using an Ar+ beam from the RILAC, whose
incident angle and energy were 30° and 50 Me V,
respectively. 3) Forward recoiled ions were detected by
an SSD at an angle of 35°. An aluminum foil filter of
15 J-Lm was inserted in order to eliminate scattered Ar+
and recoiled 0+ beams. The total ions were monitoredby an SSD at an angle of 45° .
Figure 1 shows a measured energy spectrum of thissample. The positions of t riangle marks indicate theequivalent energy of each element recoiled directlyfrom t he surface. In this condition, the largest measurable depths of He, D and H were calculated to be
as large as 0.53 J-Lm , 0.8 J-Lm and 0.73 J-Lm , respectively.
Figure 2 shows the measured depth distributions ofHe and D, together with the t heoretical distribution
10' . ~-----~~--,

0)

Not Ann eal ed
• He

b)

, ..,."","

D,-32 0t An nea l ed
• He

.,

' 0

..'.

,',

~

c)
-

.Slroi~L 5
He ions~

1. 0 ........

-+--

.~
«l
0. 5 ;;(jJ\--'::"""'O',..--'---n'7--L..:~.........,...8'0

Fig. 2. Depth distribution of He and D in YIG by ERDA((a) and (b)) and calculated distribution of implanted
He and lattice strain (c).

of implanted helium and defect-induced lattice strain
calculated by the LSS theory. In Fig. 2(a), the helium depth distribution in an as-implanted sample hasa peak at 0.4 J-Lm from the surface, which coincides withthe calculated one. While, the peak position of heliumin the annealed sample shifted toward the position of
the strain distribution peak in Fig. 2(b). The shift toward the peak position of strain from implanted sites
has been reported by Gerard et a1 4 ) and Byoung-gon
et al. 5) When the specimen was kept in a deuterium
atmosphere at 320°C for 1 hour , deuterium diffused
into the sample and concentrated at the sites of strain
distribution, differently from a homogeneous sample inwhich the deuterium distribution can be expected to
be exponential.
From the ERDA results, it is concluded that bothhelium and deuterium diffused to the defect-induced
strained region through annealing and that the concentration of these two species at the strained latticein YIG may increase photosensitive sites which bringan effective magnetic anisotropy field change.
ReferencesHey~'II "CHANNELNUMBER

Fig. 1. Energy spectrum of H, D, and He.

*

Dept. Appl. Chern. , Fac. Sci. , Sci. Univ . Tokyo** Cent. Res. Lab., Hitachi Ltd .

1) O. Okada: J. Magn. Soc. Jpn., 8 , 153 (1984).
2) T. Tsuchiya and K. Uematsu: Jpn. J. Appl. Phys. , 25,
L357 (1986) .
3) K. Yano, H. Oyama, M. Yanokura, M. Aratani, and M.
Minami: RIKEN Accel. Prog. Rep., 24, 64 (1990).
4) Ph. Gerard, P. Martin, and M. T. Delaye: J. Appl. Phys.,
57, 4058 (1985).
5) Y. Byoung-gon, E. Arai, and R. Imura: Jpn. J. Appl.
Phys., 30, 290 (1991).

125

IV. NUCLEAR DATARIKEN Accel. Prog. Rep. 27 (1993)

Status Report of the Nuclear Data Group
Y. Tendow, A. Yoshida, Y. Ohkubo, A. Hashizume, and K. Kitao
The Nuclear Data Group have been continuing thefollowing data activities since previous years. 1)(1) Nuclear reaction cross-section data (EXFOR)Compilation of nuclear reaction cross sections induced by charged particles into the exfor format has
been continued. We had originally restricted our scopeof compilation to the production cross section of only
twenty radioisotopes commonly used in the biomedical application field ; l1C , 13N, 15 0 , 18F, 28Mg, 52Fe,
67 Ga, 68Ge, 74As , 77Br, 82Br, 77Kr, 81 Rb, 82mRb,
111 In, 123Xe, 127Xe, 123 1, 124 1, and 1251. We are now
not necessarily adhering to the above-mentioned isotopes, but expanding our choice to a wider scope ofvariety. We are also picking up old data not contained .
in the EXFO R master file yet.
A transmission magnetic tape R008 containing
newly compiled EXFOR entries R0040 through R0050
with a total of 56 subentries or 63 excitation functions has been sent to the IAEA Nuclear Data Section(NDS) this year.
Cross section data for the production of radioxenon
isotopes, especially other isotopes than 123Xe, weresurveyed extensively. 2) 123Xe is the parent to produce
123 1 isotope which is one of very useful labels for radiopharmaceuticals and we have reviewed elsewhere.3)
Other radioxenon isotopes are also useful in medical
diagnosis and applications.
(2) Evaluated nuclear structure data file (ENSDF)
We have been participating in the ENSDF compilation network coordinated by the Brookhaven National
Nuclear Data Center (NNDC). The evaluation andcompilation of A = 129 mass chain has been completed and now under the editorial review at NNDC
for print in the Nuclear Data Sheets. Mass chains of
A = 127 and 118 have also been evaluated and sent to
NNDC by the other members of the Japanese groupthis year. New evaluation of A = 120 mass chain is
now in progress.
(3) Nuclear structure reference file (NSR)
We are engaged in collection and compilation of secondary references (annual reports, conference proceedings, etc.) published in Japan since previous year into
the Nuclear Structure Reference (NSR) file and sending it to NNDC. The NSR file is offered for the on-line
retrieval service by NNDC and also published periodically as the Recent References.
The compilations of 1991 and 1992 annual reports
have been completed and sent to NNDC. Secondary
sources surveyed this year are the following annual reports (in code name in NSR); RIKEN (RIKEN Accel. Prog. Rep.), JAERI-TLV (JAERI Tandem, Lin.
& V.D.G.), INS (INS Univ. Tokyo), UTTAC (Univ.
Tsukuba Tandem Accel. Center), RCNP (Res. Center
Nucl. Phys. Osaka Univ.) and CYRIC (Cyclo. Radioisot. Center, Tohoku Univ.).
References
1) Y. Tendow, A. Yoshida, Y. Ohkubo, A. Hashizume, andK. Kitao: RIKEN Accel. Prog. Rep. , 26, 135 (1992) .
2) Y. Tendow, A. Hashizume, and K. Kitao: This reportp.128.
3) A. Hashizume and Y. Tendow: RIKEN Accel. Prog.
Rep., 19, 163 (1985).

127

RIKEN Accel. Prog. Rep. 27 (1993)

Production Cross Sections of Radioxenon Isotopes
Y. Tendow, A. Hashizume, and K. Kitao
Among radioxenon isotopes, 123Xe has extensively
been studied as the parent of 1231 which is a commonlyused label for in vivo functional imaging in diagnosis
and biomedical studies. 1) Other radioxenon isotopes
than 123Xe may act as impurities in the case, but eachof them also can well be used separately e.g. as a generator of an iodine isotope or in diagnosis of ventilation
function of lungs and blood flow. Cross section datafor 123 Xe have been reviewed elsewhere. 1) We will review here the production cross sections for the otherradioxenon isotopes through charged particle nuclear
reactions.
Radioxenon isotopes are mainly produced through(p, xn), (d, xn) reactions on 1271 targets or spallation
reactions with high energy protons on Cs, Ba or La
targets. Cross section data except for the spallation
reactions are summarized in Table 1 and examples ofthe excitation curves for the (p, xn) reactions 2) are
shown in Fig. 1.

---I

J

r---i

I 1127 I (p, xn) Xe I-. :1---r- "cor -t:. ;,j ~t

1000 - - ..

I

(3)

I

. .

.

P-

101-·_··-_····_,···· ··_· 1_________ _
30
40
SO
60

l~~--~~

o

10

20

~~~

70

80

~ (MeV)

Fig. 1. Excitation functions for 1271 (p, xn) reactions(Ref. 2).

radioxenon isotopes. 10- 12 )Table 1. Production cross sections for Xe isotopes.
Energy (MeV) (Jmax (mb)

Product

Reaction

127Xe

1271 (p, n)

8 - 671271 (d, 2n)

6.5 - 89.8

470

5)

1271 (p, 3n)

21 - 67760

2,3,6,7)

1271 (d, 4n)24.2 - 89.2

800

5)

126Te (3He, 4n)

8 - 40

120

8)

125Xe

122Xe

t21Xe

178

Ref.
2, - 4)125 Te (ex, 4n)

10 - 4050

8)1271 (p, 6n)

51 - 67

>200

2,3)

1271 (d, 7n)62.5 - 89190

5)1271 (p, 7n)

62 - 67> 80

2,6,9)

1271 (d, 8n)

76 - 8945

5)

12 7Xe (36.4 d, EC) is produced through 1271 (p, n),(d, 2n) reactions with low energy protons or deuterons
and convenient for the diagnosis of respiration function.
125Xe (17.1 hr EC, f3+) is a main contaminant in
123Xe produced by (p, 5n) and (d, 6n) but the daughter 1251 (59.4 d, EC) in the extracted 123 1 may notseriously interfere because it emits a 35 keY ,-ray only.
Although 122Xe is also one of the contaminants in
the 123Xe production, it can be used as a generator
system providing 1221 for the positron emission tomography (PET). Spallation reactions with very high energy protons are also utilized for routine production of

128

References
1) A. Hashizume and Y. Tendow: RIKEN Aeeel. Prog.
Rep., 19, 163 (1985).
2) M. C. Lagunas-Solar, O. F. Carvacho, Bo-Li Liu, Yutai
Jin, and Zhao Xiang Sun: Int. J. Appl. Radiat. Isot.,37, 823 (1986).
3) M. Diksic and L. Yaffe: J. Inorg. Nucl. Chern., 39, 1299
(1977).
4) R. Colle and R. Kishore: Phys. Rev., C9, 2166 (1974).
5) R. Weinreich, O. Schult, and G. Stocklin: Int. J. Appl.
Radiat. Isot., 25, 535 (1974).
6) D. B. Syme, E. Wood, I. M. Blair, S. Kew, M. Perry,and P. Cooper: ibid., 29, 29 (1978).
7) S. R. Wilkins, S. T. Shimose, H. H. Hines, J. A.
Jungerman, F. Hegedus, and G. L. DeNardo: ibid., 26,
279 (1975).
8) Y. Homma and Y. Murakami: ibid., 28, 738 (1977).
9) M. C. Lagunas-Solar, O. F. Carvacho, L. J. Harris, and
C. A. Mathis: ibid., 37, 835 (1986).
10) M. Adilbish, V. G. Chumin, V. A. Khalkin, O. Knotek,
M. Ja. Kuznetsova, Ju. V. Norseev, V. I. Fominykh,
and N. G. Zaitseva: ibid., 31, 163 (1980).
11) N. F. Peek and F. Hegedus: ibid., 30, 631 (1979).
12) R. Michel, P. Dragovitsch, P. Englert, F . Peiffer, R.
Stuck, S. Theis, F. Begemann, H. Weber, P. Signer, R.
Wieler, D. Filges, and P. Cloth: Nucl. Instrum. Methods, B16, 61 (1986).

V.

DEVELOPMENT OF ACCELERATOR FACILITIES1. Ion Accelerator Development

RIKEN Accel. Prog. Rep. 27 (1993)

Status of the RIKEN 10 GHz ECR Ion Source
T. Kageyama, T. Nakagawa, A. Goto, M. Kase, and Y. Yano
Table 1 lists the ions that were produced with the
ECR ion source (ECRIS) from November 1992 to October 1993. We delivered 13 kinds of ion species for thelast one year in a total operation time of 184.5 days. Of
those days, 180 days were devoted to delivering beams
to the AVF cyclotron, and the remaining 8 days tostand-alone use of the ECRIS in atomic physics study.
Recent upgrade of the ECRIS 1 ,2) has allowed us to gethigh beam intensity as well as to do easy and stable

operation.
Because the number of kinds of ions demanded byusers has increased, we have installed a new gas-feedsystem as shown in Fig. 1. The system consists of ninemain-gas reservoirs, two mixing-gas reservoirs, and one
reservoirs for an expensive gas such as an enriched isotope gas.

o :Reservoire :Row-valve

Table 1. Ions produced with the RIKEN 10 GHz ECRIS
from November 1992 to October 1993.
Particle Operation Time Rate Maximum Current
P
H2+
d

ttB3+
t2C4+
t3 C4+
t4Ns+
t606+
t906+
20Ne7+
22Ne7+
27 A19+4°Artt+Total(days)(%)(e /J. A)

4.5
7.5
4
5
40.5
8.5
2
8.5
44.5
14.5
15
6
24

2.4
4.1
2.1
2.7
22.0
4.6
1.1
4.6
24.1
7.9
8.1
3.3
13.0

200
200
200
35
60
30
120
125
100
55
50
20

184.5

50

Fig. 1. Block diagram of the new gas-feed system.

References
1) T. Nakagawa et al.: RIKEN Aceel. Prog. Rep., 26, 137(1992) .
2) T. Nakagawa et al.: Jpn. J. Appl. Phys., 32, L1335(1993).

129

RIKEN Accel. Prog. Rep. 27 (1993)

Development of the RIKEN Polarized Ion Source
H. Okamura, N. Sakamoto, T. Uesaka, H. Sakai, K. Hatanaka, K. Ikegami,
J. Fujita, M. Kase, A. Goto, T. Kubo, N. Inabe, and Y. Yano
The polarized ion source has been improved in many
ways and is now ready for experimental use. 1) Several
physics programs using the polarized deuteron beam
are currently under way.2,3)
One of the major difficulty in the ion source operation was the short lifetime of the dissociator nozzle.
The white powder which was analyzed to be Si0 2 accumulates on the wall of cold nozzle and reduces thebeam intensity very rapidly. It sometimes plugs thenozzle orifice after a few days operation. This wasremedied by keeping the RF power as low as possible,
typically at 60- 80 W. Also the nozzle has been madelonger so that the white deposits accumulate far awayfrom the nozzle, expecting that the surface near theorifice will be kept clean. In this way, no reduction of
intensity is observed for at least one week.
Also a - 20 0 C alcohol circulation system has been
introduced for cooling the discharge tube in place of
the water cooling system. This was reported to be very
effective in reducing the white powder at IUCF.4) We
found , however, the amount of white deposits showedno dependence on the temperature of alcohol.
The performance of the dissociator was studied byusing a compression tube installed downstream of thesecond sextupole magnet. The maximum beam flux
into the 25 mm aperture is routinely observed to be
2.6 x 10 16 atoms/sec at 37 K nozzle temperature. The
N 2 -layer technique to prevent the strong recombination
at the nozzle works very reliably. Still the considerable
effort is devoted to improve the performance of the
dissociator.
The second major difficulty was concerned with the
ECR ionizer. In the early design of the ionizer, thesextupole magnet was electrically isolated and biased
to +7.5 kV operation voltage while the vacuum chamber remained at the ground potential. The ions wereextracted axially to the upstream direction as well asradially through the gap of the sextupole magnet. As aresult, the ions hit the RF transition units, the waveguide and the wall of vacuum chamber, which inhibitsa long-term operation. The best performance of thisionizer was 20 J-lA with 60% polarization of the ideal

130

value.
We have modified the design of the ionizer close
to the one at PSI. A quartz plasma chamber is installed inside the sextupole magnet which is kept at
the ground potential. The plasma region is pumped
through the 5 cm aperture of three-stage extraction
electrodes. A Ti sublimation pump is installed toamend the pumping power. The waveguide comes
into contact with the sextupole magnet so that the2.45 GHz microwave is efficiently directed. The plasma
is ignited typically at a power of 30-40 W. The stable
and long-term operation of the new ionizer allowed us
extensive searches of optimum conditions. Currently
the ion intensity of 140 J-lA is routinely observed with
65% polarization of the ideal value. It should be notedthat the polarization is reduced to 50% without the Ti
sublimation pump. Further improvement on the ionizer is going to be made aiming for the better pumpingof the plasma region which will lead to the better polarization. Also some modifications are being made to
the strong- and weak-field RF transition magnets toincrease the polarization degree.
The beam polarization is monitored both at the exitof the AVF cyclotron (Ed = 14 MeV) and at the exit of
the ring cyclotron (Ed = 270 Me V). The spin direction
is freely controlled by using the Wien filter downstreamof the ion source. While the beam is injected and accelerated with its spin axis inclined to the cyclotron
magnetic field, a single turn extraction does not leadto a loss in the amplitude of polarization. According
to this principle, we have succeeded in rotating thespin direction without reducing the polarization or theintensity.

References
1) H. Sakai et al.: RIKEN Accel. Prog. Rep., 25, 162 (1991);
N. Sakamoto et al.: ibid., 26, 138 (1992).
2) N. Sakamoto et al.: This report, p. 39.
3) T. Uesaka et al.: This report , p. 40.
4) V. Derenchuk et al.: IUCF Scientific and Technical Report, p. 190 (1992).

RIKEN Accel. Prog. Rep. 27 (1993)

Basic Study of Polarized He-3 Ion Source for
the RIKEN AVF Cyclotron
A. Minoh, K. Ogiwara, T. Fujisawa, and T. Nakagawa
The polarized He-3 ion source based on opticalpumping and electron cyclotron resonance (ECR) has
been studied. 1- 3 ) A principle of the ion source is presented in Ref. 1 and a block diagram of the source also
shown. Now we plan to test our concept using the
ECR ion source of the RIKEN AVF cyclotron. This
report shows the present status of the development of
the laser system, performance of vacuum system of the
ECR ion source, and investigation of the optical pumping region. The output power of the LN A laser developed for pumping He-3 atoms was 20 m Wand thespectral width was 30 GHz.2) Nacher et a1. 4- 5 ) showedthat the pumping power is more than 100 m Wand ·the spectral width about 2 GHz to generate the sufficient nuclear polarization. Such low output power iscaused by low power (1.5 W) of the Ar laser pumping
LNA laser, and the spectral width was so wide because the etalon installed in the cavity to reduce thewidth disturbed laser oscillation in such low pumping
power. Then we try to increase the pumping power byadding a diode laser (800 nm) to Ar laser because thediode laser is very compact and cheap comparing to
Ar laser. Figure 1 shows a schematic view of the double pumping system. The pumping Ar laser beam is
focused on one side of the laser rod by a focusing lensand the additional diode laser beam is focused on theother side of the lod. Then the laser cavity axis is bent
90 degree by the inserted mirror(s). The laser beam islinearly polarized in the plane of the paper by the mirror. An air gap etalon and an electrically controlled
etalon are set between the lens and the end mirror oft

Laser Output

M2

E,

M,
F,

LNA Laserrod
Diode Laser
Beam

Ar Laser
Beam
L: Internal lens

: Focusing lensE,

: Air gap eta Ion: Cavity axis change mirror

E2: Electrical controlled etalon

M, M 2 . : Laser cavity mirror
F2

F,
S

Fig. 1. LNA laser system pumped by the Ar laser and thediode laser.

the cavity. The LN A laser pumped by a diode laser
is studied with the system as shown in Fig. 2. The
LNA laser cavity consists of the flat end mirrors (M1,
M2) and intra-cavity lens (L). The output beam of thediode laser is collimated by ananamorphic prisms andfocused on the position of 2- 3 mm from the end of
the laser rod by the focusing lens (F2). The maximum
output power of the diode laser (SONY Co. 304V) is
1 W. The output beam of the diode laser has a large
divergence angle comparing with the Ar laser. Thenthe spot size of the diode laser at the focusing point
is five times greater than that of the Ar laser. Our
preliminary experiment shows that the absorption coefficient of the LN A laser for the 794 nm light is ten
times larger than that of 514 nm light of the Ar laser.
F,

A

F

M,

2

Diode laser
current controller

F, : Collimator lensF 2 : Focusing lensM, M2 : Flat end mirror
L : Internal lensA : Anamorphic prisms

Thermoelectric
controller

Fig. 2. LNA laser pumped by a diode laser for study.

These facts suggest that the beam of the diode laser
should be focused on the LN A laser rod by the focusing lens whose focal length is about one third of the
focal length for the Ar laser beam. In this case, theaxial length of the gain medium is about one third ofthat with the Ar laser. The absorption coefficient of
the LN A laser material rapidly varies arround the 800
nm wavelength region. The wavelength of the diodelaser beam is strongly dependent on the temperatureof the diode and the temperature of the diode laser isdependend on the output power of the laser. Then thetemperature of the diode laser is controlled automatically with thermo-electric controller to keep the best
laser oscillation. Figure 3 shows the pumping power
dependence of the laser output. The output power for
the focal length of 18 mm is higher than that of 30
mm.
The He-3 gas pressure in the pumping region should
be between 0.1 Torr and 1 Torr to obtain the good
nuclear polarization. 6 ) However, the ECR ion source
should be operated under pressure of 10- 5 to 10- 7
131

~ 20
M

~
0

0.-

M

Q)

.rg 10<Z....:lq)
ill power (mW)ilO-7~

Fig. 3. The pumping power dependence of the diode laser
pumped LNA laser.

Torr. Figure 4 shows the Pyrex tube for the pumping
region and ECR ion source. The exit channel apertureof the tube is about 0.1 mm and the length 10 mm
to hold the gas for a long time in the tube and keepa good vacuum of the ECR ion source. We measured
the pressure of each section by feeding He-4 gas. The
result shown in Fig. 5 is satisfactory. In the pumping
region, the magnetic field of 0.01 T is enough to holdthe nuclear polarization. However, the diagonal component of the magnetic field against z-axis should beless than 0.3 x 10- 5 T to obtain good polarization. 7)
Furthermore, the magnetic field of the ECR ion source
is about 0.3 T. Thus, in the pumping region, the magnetic field have to be carefully adjusted. The measured
magnetic field in the pumping region leaked from the
ECR ion source was less than that of the earth. Then
we plan to generate the magnetic field of the opticalpumping region with a usual solenoid coil surroundedRF(10GHz)

Pyrex tube'"~~~~~~~~=¥~~;)-.I

Gas inlet

Fig. 4. Optical pumping region and ECR ion source.

132

ct

Third Stage

Pressure of the Pyrex tube (Torr)

Fig. 5. Vacuum pressure of the ECR ion source.

by an iron cylinder. The magnetic field of 0.3 T in
the ECR ion source is just the critical strength to holdthe nuclear spin,/) so a higher field as 1 T is desirable
to hold perfectly the nuclear spin. However, it is ofenough strength in order to see whether our concept
is good or not. We test the whole system in the near
future.
References
1) T. Fujisawa, A. Minoh, Y. Taniguchi, S. Ishii, K.
Hatanaka, and Y. Oshiro: RIKEN Accel. Prog. Rep.,
22, 222 (1988).
2) A. Minoh, K. Ogiwara, and T. Fujisawa: ibid., 23, 113(1989); 24, 136 (1990); 25, 103 (1991); 26, 139 (1992).
3) T. Fujisawa, A. Minoh, Y. Taniguchi, and K. Hatanaka:
Int. Workshop on Polarized Ion Source and Polized GasJet, Tukuba, Feb., p. 12 (1990).
4) P. J. Nacher and M. Leduc: J. Physique, 46, 2057 (1985).
5) M. Leduc, S. B. Crampton, P. J. Nacher and F. Laloe:
Nucl. Sci. Appl., 1, 1 (1983).
6) F. D. Colegrove, L. D. Schearer, and G. K. Walters:
Phys. Rev., 132, 6, 2561 (1963).
7) T. B. Clegg: Workshop on Polarized 3He Beams andtargets, Princeton, New Jersey, p. 25 (1984).

RIKEN Accel. Prog. Rep. 27 (1993)

Development of a New Type of Single-Bunch Selector
N. Inabe, M. Kase, T . Kawama,* M. Hemmi, O. Kamigaito,
M. Nagase, 1. Yokoyama, A. Goto, and Y. Yano
A new type of single-bunch selector has been developed and installed on the beam transport line between the ECR ion source (ECRIS) and the AVF cyclotron. Figure 1 shows a schematic drawing of thesingle-bunch selector system. Electrodes are connected
to a DC power supply via a switching module. A pulse
for switching onloff is created by a function generator
and sent to the module. Characteristics of the single bunch selector are summarized in Table 1. In thepresent method, the single-bunched beam is obtained

Swept bunches
Tlxm:

Time picking up the beam

T trav:
Toff :

Travelling time through electrodes
Duration of no electric field

Tr :Reptllion time

T ace:

Interval the A VF cyclotron accepcs
the bunch using a buncller

SwitchingFig. 2. Production scheme of a single-bunched beam withthe selector.

Fig. 1. Systematic drawing of the single-bunch selector.

Table 1. Characteristics of single bunch selector.
Gap bet ween electrodes
Length of electrodes
in beam direction
Width of electrodes
Voltage
Repetition rate
Rise time
Duration time (Toff)

60mm
80mm
100mm
0- 3 kV (DC)0-25 kHz
20 ns> 150 nsfrom a continuum beam of the ECRIS before entering
the AVF cyclotron, while in a usual method a singlebunch selection is made from a bunched beam after acyclotron. Since the single-bunch selection is made at
low energy in the present method, the whole system
can be small and of low cost.
Figure 2 shows how to make the single-bunch selection. A discrete beam can be produced from the beamof the ECRIS using an electric field which is switched
off for a duration of Toff. The duration of the discrete beam picked up by the selector (T bon ) is given
by subtracting a traveling time through the electricfield from T off. To get the single-bunched beam, Tbon
is necessary to be as short as possible so as not to overlap the previous and the next bunches of the AVF cyclotron. To get as high-intensity single-bunched beam*

Sumijyu Accel. Service, Ltd.

as possible for a given repetition time (T r), on theother hand, Tbon should be longer than T ace (a duration that the AVF cyclotron can accept the bunchwhen using the beam buncher). In the system, unnecessary beam kicked away by an electric field is swept
out at some places of the beam transport line to the
AVF cyclotron.
A performance study of the single-bunch selector
was carried out for the 7.45 Ke V Ht beam from the
ECRIS which is accelerated to 7 MeV Inucleon by the
AVF cyclotron with an RF frequency of 16.3 MHz. The
setup is shown in Fig. 3. Time structure of the beam
after the AVF cyclotron was measured by using a timeof flight (TOF) between a reduced RF signal and atiming signal of a micro channel plate (MCP) with atarget.!) Beam current was measured with a Faradaycup.
A VF cyclotron

Fig. 3. Setup for a performance test of the single-bunch
selector.

Figures 4a and 4b show typical examples of the TOF
spectra. The T off is 200 ns (Tbon = 106 ns) in Fig. 4aand 400 ns (T bon = 306 ns) in Fig. 4b. The Tr is133

50 J-LS and a voltage between the electrodes is 350 V
in the both figures. The two peaks in Fig. 4a do notmean that the selector failed to make a single-bunch
selection but they mean that the same single-bunch
inside the AVF cyclotron is extracted with two-turns.
The four peaks in Fig. 4b whose strengths change alternately mean that the single-bunch selection was notcompleted due to long T off compared with the case of
Fig. 4a. Production mechanism of those peaks is explained in Fig. 5. In the case of Fig. 4a, the time structure was measured for several positions of the targetof the MCP to cover the whole region of the beam
and it was ensured that no other peak existed. Thisshows that the single-bunched beam can be obtained

Harmonic number = 2

DTime structure of beam
AandC:
Two turns e:uraction of one bunch

N
A

BandD:
Two-turns extraction of another bunch

B

Fig. 5. Time structure of the beam from the AVF cyclotron for two bunches with two-turns extraction.
2000~-----------------------.
~
2T _ avf

r-

j

1500

4a

Toff = 200 ns

c::

6 1000u
500
O~--~--~~--~----~--~

2500
2000

~ 1500

200
4b

400

600

800 1 000

Toff = 400 ns-l f- 2T_avf
1~<3 1000

500

O~--~----~--~----r---~200

400 600
Channel

800 1 000

Fig. 4. Examples of time spectra of the beam: 4a, in thecase of T off = 200 ns; and 4b, in the case of T off = 400
ns. T _avf means the RF period of the AVF cyclotron.

134

if the beam inside the AVF cyclotron can be extractedwith the single turn. In fact , the careful tuning of the
AVF cyclotron can realize the single-turn extraction. 2 )Current of the single-bunched beam was 2.7 enA andthis value was almost equal to that calculated by thecurrent of continuum beam divided by the number ofbunches during T r . This shows that almost all fractionof the part selected with the single-bunch selector is
accepted by the AVF cyclotron.
To get more intense single-bunched beams, we plan
to increase the repetition rate up to as high as 1 MHz(T rI"V 1 J-Ls) using a higher speed semi-conductor device.
References
1) T. Kawama et al.: This report. p. 135.
2) A. Goto et al.: This report. p. 6.

RIKEN Accel. Prog. Rep. 27 (1993)

Development of a Beam Phase Monitor
with a Micro-Channel Plate
T. Kawama,* M. Kase, T. Nakagawa, N. Inabe, I. Yokoyama, A. Goto, and Y. Yano
A new beam monitor with a micro-channel plate(M CP) has been developed 1 ) for the measurement oftime structure of various kinds of ion beams from the
RIKEN Ring cyclotron (RRC) and the AVF cyclotron(AVF). This probe has a good sensitivity with a large
dynamic range of beam intensities, compared with aconventional phase monitor with a capacitive pick-up
electrode.
The structure of the new phase probe is shown in
Fig. 1. An MCP is set parallel to the beam axis. A
small target of 0.3 mm¢ tungsten wire is strung inparallel with the MCP surface. The target intersects

and analyzed by a multi-channel analyzer. The device
is installed inside beam-diagnostic chambers located in
the extracted beam line of the RRC and the AVF.
Figure 2 shows a typical example of time spectrum
obtained for 100 MeV /u 18 0 beam from the RRC operated with the AVF. Beam bunches appear with timeintervals of an RF period of the AVF (TAVF) which isequal to 2 x TRRC (an RF period of RRC). The time
spread of a beam bunch was measured to be 940 ps
in FWHM, corresponding to an RF phase spread of
about 10 degrees.

180 8+ fRRC

= 29.0 MHz

h = 5 E = 100 MeV/u· I--TAVF ~FWHM= 940psecRodoElectrode

, ~

.l
o

100

&

200

Sl it

Me?

25mm

/

Fig. 1. Structure of the new phase probe with an MCP.
All electrodes are made of stainless steel and supported
by ceramic insulator rods. Each electrode is based sothat a uniform field is produced from the wire to the
MCP.

only a small fraction of a beam (a few percents at the
maximum). Electrons and/or photons (considered tobe mainly X ray) produced on the target by ion beams
are introduced to the MCP through double slits. There
are four sets of electrodes for producing an electric field
for the electron acceleration. The whole electrodes
including the target and the MCP can be moved remotely in perpendicular to the beam axis , keeping a
constant distance (50 mm) between the wire and the
MCP. In this way the position of wire with respect tothe beam is selectable in order to adjust a signal rate
(0.1-10 kcps) from the MCP. Fast and large signals
with a rise time less than '1 ns and with a gain larger
than 107 a:re obtained from the tapered coaxial shaped
anode of the MCP. The timing of these signals with respect to the time origin determined by an RF master
oscillator is measured with a time-to-analog converter

*

300

400

500

Channel No.

600
4 _

700

800

900

1000

Time

Fig. 2. Example of time spectrum of signals from the
MCP for 100 MeV lu 18 0 beam. Large peaks are due
to a main beam, and small peaks are due to the effectof multi-turn extraction.

The position of peak in Fig. 2 is always relating to abeam phase to an RF phase. This allows the device towork as a phase probe. Figure 3 shows that the changeof magnetic field in the RRe causes a shift of the peak.
We can detect a deviation less than 10 ppm of a magnetic field from the isochronous one. An operator can

84 Kr 13+f.RC = 20 MH z

h = 10 E = 10.5 MeV/u~ ~------------------~

~
.....

~ 0

I------~~-----'---I<l~

L -_ _ _ _ _ _ _ _~_ _ _ _ _ _ _ _~·0.0035o0.0035t.B/B( %)Fig. 3. The peak shift (that is, beam phase) vs. thechange of magnetic field in the RRC. When 6.B/B iszero, the magnetic field is isochronous. A dashed line
results from the following calculation.

Sumijyu Accelerator Service , ltd.

135

stabilize the magnetic field by adjusting a magnetic
current to keep this peak at the same position.

i.p =-360 x ~B/B x Nturn x Nhheight peaks follow it. The number of peaks in eachgroup corresponds to a harmonic number of the RRC.
The details were reported in Ref. 1. In this way, we
can observe to what degree the single-turn extractionis achieved for cyclotrons.

~B : the change of magnetic field

40 Ar 5+

E=7MeV/u fRRc=18MHz h=11

B : a magnetic field(TRRC = 56ns)

Nturn : a number of turn in the cyclotron

600

Nh : a harmonic number

500

-fi

This phase monitor also works as a monitor which
gives information about the single turn extraction. In
case of the RRC coupled with AVF, a harmonic number of the RRC is an odd number of five, and TAVF
= 2 X TRRC. Considering these conditions, we conclude that small peaks, which are observed at the middle points between large main-beam peaks as shownin Fig. 2, are due to the multi-turn extraction of theRRC. In other cases (e.g. for the AVF or for the RRC
coupled with RILAC), we can also observe the peaks
which are due to the multi-turn extraction by use ofan electric chopper. 2) Figure 4 shows an example ofthe time spectrum obtained, when a beam is chopped
for the duration of 1.2 J.LS, for the case of the RRC
harmonic number of 11. In case of the multi-turn
extraction, after a beam is switched off at A, elevensmall peaks still remain and, after switched on at B,
another group of eleven peaks appears first and full

136

C
:::I
o

U

400
300
200
100

o

o

100

200

300 400

500

Channel No.

600

700

800

900 1000

TIME -

Fig. 4. A time spectrum of beam bunches when the beamis cut partially (1.2 J.Lsec) by the beam chopper installedin the RILAC injection line.

References
1) M. Kase , T. Kawama, T. Nakagawa, N. Inabe, I.
Yokoyama, A. Goto , and Y. Yano: Proc. the 9th Symp.
on Accel. Sci. and Technol. in Japan, 1993 Tsukuba, p.
474 (1993) .
2) M. Hemmi, H. Kumagai , and Y . Miyazawa: Proc. Linear
Accel. Meet. in Japan , 1992, Sendai, p. 309 (1992).

RIKEN Accel. Prog. Rep. 27 (1993)

Development of the Second-Harmonic Buncher
for the RILAC
S. Kohara, A. Goto, Y. Miyazawa, T. Chiba, M. Hemmi,
Y. Chiba, E. Ikezawa, M. Kase, and Y. Yano
The second-harmonic buncher was constructed andinstalled on the injection beam line of the RILAC in
March 1993 to increase beam intensity. It has been inroutine operation since then. It has good impedance
matching to a power feed line without adjusting device
in the required wide frequency range. Beam intensity was increased by 50% with both the fundamentalfrequency and the second-harmonic bunchers. The details of the design and the structure of the secondharmonic buncher were reported elsewhere. 1,2) The
test results for the completed buncher are presented
in this report.
A cross sectional view of the new buncher is shownin Fig. 1. Position of the movable shorting plate andcapacitance of the variable capacitor are the two parameters determining a resonant frequency. Optimum
combinations of these parameters, which realize thebest impedance matching, are determined from measurements (as shown in Fig. 4).

200
N

:I:

0

6 150

0

0 :

o

go

100

::l
0-

•

~

c

50

'"c:
~

•

•

•

0

0::

o~~~~--~~~o 100 200 300 400 500 600
Position of the movable shorting plate L (mm)Fig. 2. Measured resonant frequencies as a function of position of the movable shorting plate for fundamental (.)
and higher (0) modes with a nearly optimum parameter
set.
2000

1500

0'
0
0

g

:; 1000
>

0

&

500

o '---""---""----'---'---'---'---.JMovable Shortingplale

30 40 50 60 70 80 90 100
Resonant frequency (MHz)Fig. 3. Measured Q-values as a function of resonant frequency with a nearly optimum parameter set.

E

..c:

-S

60

9 50 rooo 0

'"c:~

~

o

5

10 (em)Fig. 1. Cross sectional view of the second-harmonicbuncher.

The frequencies of the fundamental and higher
modes measured with a nearly optimum parameter set
are shown in Fig. 2 as a function of position of the
movable shorting plate. The resonator has a parasitic resonance in the vicinity of 150 MHz for every
position of the movable shorting plate. This is a halfwave-length mode standing on between the drift tube
and the o'ther open end terminal and having a nodenear the position of the capacitor. The measured Qvalues are shown in Fig. 3. They are from 1000 to 1600.
Figure 4-A shows input impedances at the feed point
measured with the optimum parameter combinations

~

40

....~

30

0

0

A

0
0

0

0

u

c:

'§c..

.5

:;
c..
..5

20
10

0
30 40 50 60 70 80 90 100
Resonant frequency (MHz)Fig. 4-A. Measured input impedances at the feed point as
a function of resonant frequency with the optimum parameter set in Fig. 4-B. The imaginary parts of the
impedances are zero.

shown in Fig. 4-B. The input voltage standing wave
ratio (VSWR) increases to 1.25 at 90 MHz, but gives
practically no problem.
The drift-tube voltage was measured by a calibrated
capacitive voltage pickup. The results of the power
test under atmospheric pressure are shown in Fig. 5.
137

--

- 0 - Position
Capacitance

E
S

.,

..J

600
;;
0.500
el)

80
B

70

c

60

0

SO

'2 400~.,::E 300

'"0
;>

E 200
.::;
100

.,

c

0
30 40 50 60 70 80 90 IOUResonant frequency (MHz)

0..
~

o
40

o 0

.::;

:-;

.,

~

o

0

20 0

8.

.....0

.,u

::::l

o8- 0

~
'u

~.L...-.L...-..L--'---'---'----'

30 40 SO 60 70 80 90 100'"P-Resonant frequency (MHz)U

Fig. 4-B. Optimum combination of positions L of the movable shorting plate and capacitances of the variable capacitor.

o60.....o

::E

30

10

Q..

~

'"P.,'"u

-S

'0

0

9

.,...

' <)

40

20

0

~

~

'!a'";>

II.)

:~

CL:'

Fig. 5. Measured output powers of the amplifier for therequired peak drift-tube voltage of 1.5 kV.

Table 1. Results of the beam test.

The required peak drift-tube voltage of 1.5 kV (3kV /2gaps) was obtained in the whole frequency range. Reflected power from the resonator to the amplifier wasless than 1.2W. Stability of the drift-tube voltage wasbetter than ±1 x 10- 3 and stability of the phase ±0.5°.
Amplitudes of the higher mode were observed athigh power levels. They are about 3% of the fundamental ones in the worst case and cause negligible effect on performance of the buncher. 2)
Multipactoring phenomenon occurred in the power
test under vacuum, . but it was easily overcome by apulse operation.
Results of the beam test with Ar 6 + ion are listed inTable 1. The beam intensity at the exit of the RILAC
was increased from 1.7 to 2.5 j.1A.

138

RILAC
Cockcroft
Fund. buncher
Second buncher
Intensity

28 MHz283 kV
28 MHz1.3kV
no useno use28 MHz283 kV
28 MHz2.0 kV
56 MHz
1.0kV

1.7 J.lA

2.5 j.1A

References
1) S. Kohara et al.: RIKEN Accel. Prog. Rep., 26 , 142(1992) .
2) S. Kohara et al.: Proc. of the 9th Symp. on Accel. Sci.
and Technol. , KEK, p. 157 (1993).

RIKEN Accel. Prog. Rep. 27 (1993)

Design of a Variable Frequency RFQ Linac for RILAC
O. Kamigaito, A. Goto, Y. Miyazawa, T. Chiba, M. Hemmi, M. Kase, and Y. Yano
A variable frequency RFQ has been designed as a
new injector for RILAC. It will accelerate ions with arange of M/q = 7-28 up to 450 keY /q in the CW mode.
The operational frequency will be varied between 17
MHz and 35 MHz. This RFQ and the 18 GHz-ECRIS,
which is also under design,l) are expected to greatly
increase the heavy ion beams for RILAC in the near
future.
One of the most important problems to be solvedin the design is the frequency-tunability in the RILAC
frequency range. As discussed below, we have proposed the "folded coaxial" structure for the cavity tosolve the problem.
Figure 1 shows a schematic drawing of the RFQ cav- .
ity. The horizontal vanes are supported by the cavity
wall on their ends. The vertical vanes are fixed on the
inner surfaces of a rectangular tube which surrounds
the horizontal vanes. This tube is settled on the ceramic insulators placed on the bottom of the cavity. A
stem suspended from the top of the cavity is in contact with the rectangular tube. A moving short is put
around the stem, which varies the resonant frequency.

Cavity Wall

Stem

Movable Shorting Plate

Stem

I

Vertical Vane

Horizontal Vane

Rectangular Tube

Fig. 2. Magnetic flux of the fundamental mode.

r=t::::;;:=1=:::::!;;;:t=::~ Rectangular Tube

Open - end

Outer Surface of the
Rectangular TubeI

Z2 > Z1

E

E

o
o

0>

Fig. 1. Schematic drawing of the RFQ cavity.

The magnetic field of the fundamental mode is described in Fig. 2. The magnetic flux surrounds thestem, the rectangular tube, and the horizontal vanesin the tube. The direction of the flux is reversed at
the middle of the vanes, and the magnetic field vanishes there. Figure 3(a) shows a conceptual drawingof the half of the cavity with the magnetic flux. As
shown in the figure, this structure is equivalent to a"folded" coaxial cavity: If it is unfolded, it becomes a"normal" coaxial cavity illustrated in Fig. 3(b). In ourdesign, the characteristic impedance of the short-end

Fig. 3. (a) Conceptual drawing of the half of the RFQ
cavity. (b) "Unfolded" >.14-coaxial cavity. Zl is thecharacteristic impedance of the open-end side and Z2
is that of the short-end side. In our design, Z2 is muchlarger than Z1.

side is much larger than that of the open-end side.
This "folded coaxial" structure has the following advantages. The first one is the compactness of the cavity even for the low frequency. In addition to thefolded structure, the difference of the characteristic
impedance plays a significant role for it. Such cavities as shown in Fig. 3(b) are known to provide lower
resonant frequencies than those having the same characteristic impedance over the whole length. The otherone is the wide frequency-tunable range of the cavity.
Since the shorting plate moves within the short-end
side, where the characteristic impedance is large, theelectric length of the cavity changed by the plate islonger than the actual stroke.
The calculation using the computer code MAFIA
has shown that the resonant frequency of the fundamental mode can be varied between 17 MHz and 35
MHz, by changing the position of the shorting plateby 575 mm. In the calculation, no modulation was139

added to the vane having the mean bore radius listed
in Table 1. The calculated Q-values are 9700 at 17
MHz and 4800 at 35 MHz. Although there appears
asymmetry of the electric field between the upper andthe lower half in the rectangular tube, it is 2% at thelargest and would yield negligible effects on the acceleration. Further analysis of the asymmetry and themethod to eliminate it are under progress.
Using a simple cavity as shown in Fig. 4, we havemeasured the resonant frequency and the field distribution of the folded coaxial structure. The measured

Table 1. Key parameters of the RFQ.
Vane length
Frequency
M/q
Incident energy
Output energy
Intervane voltage (V)Normalized emittance
Minimum bore radius
Mean bore radius
Maximum modulation
Focusing strength (B)Max. defocusing strength
Final synchronous phase
Transmission (0 rnA)

142 cm
16.9- 35.0 MHz
7- 28
10 keV/q
450 keY /q33.6 kV
145 7r mm-mrad
0.417 cm0.770 cm
2.7
6.80
-0.30
-25 deg.
96%

MovableShorting Plate

39.21MHz E-Distr.
~r-------------------~

fr-------_Jil

50

'g

40

.Q
,;,

30

~

20

...

10

o

.\
10

20

30

40

50

z ( em )Fig. 5. Electric field distribution between the inner andthe outer electrode of the test cavity. The abscissa (z)is indicated in Fig. 4.

resonant frequency was in very good agreement with
the MAFIA calculations.
The electric field distribution of the fundamental
mode is flat along the acceleration axis as shown in
Fig. 5. Thus this structure would be suitable for the
RFQ cavity.
The vanes are designed in the usual way: they
are divided into six sections according to the designing method developed at INS .2 ) By use of the computer codes GENRFQ and the modified version of
PARMTEQ , the vane parameters have been optimized
to get the high beam-transmission efficiency and theshort vane length.
The key parameters are listed in Table 1. The extraction voltage of the ion source is assumed to be 10
k V. A considerably small value of the intervane voltage V = 33.6 kV is sufficient to get the final energy of
450 ke V / q. The calculated power losses are 4 k W at
17 MHz and 15 kW at 35 MHz.
Now a half-scaled model for the cold test of the cavity is under fabrication. It will be also used for the
study of the vane alignment.

E
E

o

'"

References

Fig. 4. Schematic drawing of the test cavity.

1) T. Nakagawa et al.: Proc. of the 9th Symp. on Accel.
Sci. and Technol., p. 98 (1993).
2) T. Nakanishi, N. Ueda, S. Arai, T. Hattori, T .
Fukushima, Y. Sakurada, T . Homma, N. Tokuda, S.
Yamada, A. Mizobuchi, and Y. Hirao: Particle Accel. ,20, 183 (1987).

N

Rectangular Tube

140

RIKEN Accel. Prog. Rep. 27 (1993)

Construction of RIKEN-RAL Muon Research Facility
K. Nagamine, T. Matsuzaki, K. Ishida, and I. Watanabe
By using intense and high quality negative muons,many interesting and important experimental researches in the field of interdisciplinary science will become realised; some significant examples are muon catalyzed fusion, muonic X-ray element analysis and negative muon spin rotation/relaxation/resonance studies
for condensed matter.
The high intensity and rapid-cycling proton synchrotron of the ISIS accelerator of Rutherford Appleton Laboratory (RAL), which had been constructed
for a spallation neutron source, is most suited for thepulsed muon generation. The ISIS can produce 800
MeV protons with 70 ns width and 340 ns separationand 50 Hz repetition at an average current of 170 f.-LA . .
In order to promote science research with pulsed negative as well as positive muons, an agreement has been
established between RIKEN and SERC for RIKEN toconstruct muon facility at the north-side opposite to
the existing surface positive muon channel at ISIS.
As the best beam channel for the negative muon
production, we have adopted the beam channel witha decay section of superconducting solenoid like PSIor UTMSL/KEK. The design and construction of theadvanced superconducting muon channel was started
in 1990.
(1) Production target and pion injector
The production target presently in use for the southside surface muon channel will also be used as the production target for the present channel, where one ofthree graphite targets with 2 mm, 5 mm, and 10 mmthickness can be selected. Proton beam-line vacuum
from the ISIS accelerator is separated by a 100 f.-Lm
thick Al window before the first quadrupole magnet.

A radiation-resistant mineral-insulating conductor isused for the front-end quadrupole (Q1). In order togain a large solid angle, a large aperture quadrupole
with an aperture of 14 inches is used for the Q2. After the momentum analyzing first bend, a momentum
selecting slit and a vacuum valve are placed. At thestraight downstream after the bender, the Cerenkov
counter is placed for the timing pulse for the pulsed
muon experiment.
(2) Superconducting solenoid
The basic parameters for the superconducting
solenoid are quite similar to those installed by the
UTMSL Group either at UTMSL/KEK or at TRIUMF; a total length of 5.5 m, a bore diameter of 12
cm and a field of 5 T. The solenoid is cooled indirectly
by a forced flow of a supercritical 4He of 4.6 K and
10 atm through a cooling tube tightly wound aroundthe coil. The cold bore of solenoid stays in the common vacuum space of the muon channel separated by
the Al foil placed before the front-end quad and the foil
placed at the vacuum duct ends for three experimental
ports. The solenoid and its cryostat were completed in
May 1993 and installed at ISIS in early fall of 1993.
(3) Helium refrigeration system
The system is composed of a Linde TCF 50 turbine
cold box and a MYCOMP screw compressor. It can
produce simultaneously (a) a supercritical helium forthe solenoid, (b) an intermediate temperature helium
flow for 100 K shield of the solenoid cryostat, (c) aliquid helium flow for power-lead cooling and (d) atwo-phase helium flow for the experimental magnet.
The system was installed at ISIS in May 1993 and atest of the unit performance was completed.

141

RIKEN Accel. Prog. Rep. 27 (1993)

Theoretical Study of the Relativistic Cyclotron Maser Cooling
H. Suganuma, H. Toki, and 1. Tanihata
Very recently, Ikegami proposed a new concept on
the beam cooling; it is named as Cyclotron Maser
Cooling (CMC). The CMC utilizes the relativistic effect on the cyclotron oscillation of the beam aroundthe beam axis due to the magnetic field applied in
the beam direction. The particles are cooled down
to the microwave frequency provided by an external
oscillating electric field which is applied perpendicular
to the beam direction. This new method was claimed
to cool down beams of various kinds in the matter ofmicroseconds. 1,2) This is an extremely exciting finding and it would be very important to pay attention
from the theoretical side to its feasibility and also to
the applicability. We would like to study the CMC
purely from a theoretical view point. In particular, we
would like to derive the cooling condition and the cooling time in the laboratory frame , paying attention to
the relativistic effect on the beams.
The details of the derivation of cooling conditions
are provided in Ref. 3. We comment here only thecomparison of our results with those of Ikegami. 1 ) All
the results would coincide with the corresponding onesof Ikegami , if we put m in place of m* in various places.
This difference originates from the fact that, in thederivation of Ikegami,l) the 'transverse "( factor', "(T,defined as rT = 1 + i we/m in the beam rest frame
remains unchanged by the Lorentz transformation to
the laboratory frame. One should, however , change rT
to ,T* = 1 + i we/m* in the Lorentz transformation.
We summarize here the calculated results of thecooling condition and the cooling time. As reasonable parameters for the non-relativistic electron, we set
the magnetic field H = 0.1 Tesla (lk Gauss) and thepower eAo = 1 ke V. The life time of electrons in theLandau orbit due to the electromagnetic transitions is
8
T rv 10- sec. These values provide the radius R rv 5
cm and the cooling time T rv 2 X 10- 9 sec. The cooling time is an extremely small number, which agrees
with that of Ikegami. What then happens if the beam
velocity becomes relativistic? Let us consider the caseP z rv 5 MeV , which corresponds to rz rv 10. With thesame parameters for the all the devices, we find thatR rv 50 cm and T rv 2 X 10- 6 sec. Hence, the CMC isstill powerful even in this case. Even the energy would
become ultra-relativistic, if we can use stronger electric and magnetic fields and bigger size devises accor-

142

dingly available in the present technology, we are able
to cool down the electron beam up to an extremely
ultra-relativistic energy. This statement is due to thedependence of the cooling conditions on the magnetic
field as R ex: H-1.5 and T ex: H- 3 as can be derived
from the expressions in Ref. 3. As for the power of theoscillating electric field, it changes the cooling time toT ex: (eAo) -2, while other quantities are unaffected.
The situation becomes severe for protons due to thelarge rest mass. In fact , in order to achieve the CMC
cooling, we have to use much more powerful electromagnetic fields. Taking H = 10 Tesla and eAo = 1
MeV, we find that the radius and cooling time are (use11
T rv 10- 5 sec); R rv 12 cm and T rv 7 X 10sec fornon-relativistic protons. This result agrees with that of
Ikegami. 1 ) As the beam energy increases , the radius of
the magnetic field goes as and the cooling t ime as r~ .
Hence, even for rz rv 10; P z rv 10 GeV, R rv 1.2 m andT rv 7 X 10- 8 sec. The cooling time is still impressive.
However, the radius R rv 1.2 m may be close to thepresent technical limit. Concerning the length of thecooling devise, the length of the magnetic field L would
be L rv 20 m in this case, which may be of the orderor less of the circulation length of the cooler ring.
In conclusion, we have studied theoretically the cooling conditions and the cooling time of the CMC forvarious non-relativistic and relativistic beams. We
have reproduced the results of Ikegami for the nonrelativistic case. As for the relativistic case, however,
we have found significant relativistic effects on thecooling conditions, which deviate largely from thoseof Ikegami. The radius of the Landau orbit to becooled down increases like R ex: rz with rz being defined as m* = rz m. The cooling time also increases
like T ex: r~' As a consequence, the cooling conditionsof the CMC become progressively severe as the beamenergy increases. We conclude therefore that the CMC
is a promising cooling mechanism for beams which are
not very relativistic.

,z

References
1) H. Ikegami: Phys. Rev. Lett. , 64, 1737; 2593 (1990).
2) F. Kullander: Doctor thesis "Cyclotron Maser Cooling,a first experiment study", Osaka Univ. (1992).
3) H. Suganuma, H. Toki, and I. Tanihata: to be published.

2. Synchrotron Radiation Source Development

RIKEN Accel. Prog. Rep. 27 (1993)

Correction of Emittance Modulation by Linear Coupling
H. Tanaka and A. Ando
The vertical emittance of the SPring-8 storage ringis mainly given by linear coupling of betatron oscillations and varies along the ring. The coupling should
be reduced to around 1% to keep very high brilliance.
The behavior of coupling motion is completely described in normal mode. In this flame, oscillation amplitudes of each particle oscillate sinusoidally. The envelopes of these amplitudes for all the particles areconstant along a ring. The emittances in the laboratory flame are obtained by the projection from thenormal mode. This projection is a kind of the coordinate rotation. The rotation angle depends on the fact
how many and how strong skew quadrupoles are, andthen varies along a ring. This causes the modulationof the maximum emittance. Radiation damping andexcitation cannot smear out this modulation because
the damping time is about 100 times as large as theperiod of coupling motion.
The analytical formulae of the maximum emittancemodulations are derived by a perturbation approach l )and the correction method to reduce not only the coupling coefficient but also the maximum modulation
along a whole ring is also obtained.
Figure 1 shows a typical example of the maximum

variation of the vertical emittance, where the verticalalignment errors of sextupoles are assumed to be 0.1
mm in rms. Triangles and open circles show tracking
results and analytical estimates, respectively, when theinitial amplitudes are set to the predicted ones by thelinear coupling resonance. The real line shows the average emittance given by this resonance.
The correction scheme is simulated as follows. Shaking the beam coherently in the horizontal direction,
vertical oscillations are observed at 20 BPMs along thering. At every BPM the most effective skew quadrpole
magnet is selected and excited at the 20% level of thenecessary strength to reduce the coupling oscillation
amplitude at this point. The iteration is continued
until the residual coupling oscillation becomes smaller
than about 12% of the horizontal one (i.e. 1.5% coupling). In Fig. 2, some examples obtained by particle tracking are shown. Open symbols and real lines
show the modulations before correction, and closed
and dotted ones show after the correction. The different shapes of symbols correspond to the different
rms values of alignment errors.
~
0

><
><
ro

t::::::.

:0ro

10-9

E

~

_>.

~ Pertllrbation Melhod

i ><

•

ro

Phase Space Area I 21t

E- - Single Resonance Approx.

......>.

'.

0

<..)

c

~

·8

>
.c
U

<..)

·e

50
40
30

.....0
0

20

eo
.5
0..

to

U

~

60

E
0

·u
t;::

r.tl

70

::::s

0

0

U

>

E
::::s
E

0
0.00

1.57

3.14

4.71

6.28

Azimuthal Position e [fad].~::E 10- 10
0

1.57

3.14

4.71

Fig. 2. Correction simulation.

6.28

Azimuthal Position e [fad]References
Fig. 1. Modulation of the max. vertical emittance.

1) A. Ando: Particle Accelerators, 15, 177 (1984).

143

RIKEN Accel. Prog. Rep. 27 (1993)

Survey for SPring-8 Storage Ring
S. Matsui, 1. Takeshita, and K. Kumagai
A 1.4 km circumference of the SPring-B surrounds
Mihara-Kuriyama Hill which is 50 m higher than thestorage ring level. In order to set many magnets precisely, the reference points for magnet alignment arenecessary. Thus we made monuments around the ring.
We surveyed 12 reference points (outside the ring) and
15 monuments (on the ring) in January 1993 to determine the monument position before the ring building
is constructed. The number of measurements is 114 forangle and 106 for distance. Figure 1 shows the error
ellipses of this survey result.

SR6

_c:;)
SR6A~_
I

SR5

.

0--0

I

~

COl

'*11

S R1

o

(0

--_

COS

- - - __

6--_~'t 4

I

~

COL

C4~r::> ,/ \,

,:

I

I

I

,
1

I

I

I

clD'
I
I
SR8

/

6)

S R3

.C4~G
I
I

I

I
I

I
I

I
I
I
I

I

:
S R 9

Js;(

.
,f2l

L..-=...- - - -- - --

~

-----

-----__

e

• C3l

B

1

't:l. ____ - __ L

_ 1".31-- - - - ,S~ I "

I-------.l;J~

S R 2

0
1 . ....

SRI'"
SRIO

100111

Fig. 1. Error ellipses.

Ten geodetic points (SRI-SRI0) and sub-points(SRIA and SR6A) are positioned outside the ring. We
cannot surround the Hill by a triangle. However, bysetting the sub-points SRIA and SR6A, the circumfer-

144

ence is surrounded by a quadrangle, which has a fewersides (Fig. 1).
We made concrete monuments similar to a Japanese
tomb stone.
While surveying, a 1m high standmounted on a monument was used for setting the survey instrument or the target. These 15 monuments(COI-C47) for the magnets alignment are placed at theintersected points of the straight lines on both sides ofthe bending magnet. These monuments are also used
to construct the concrete tunnel.
An automatic plummet (WILD NL) was used fortripod setting.
The measurments of the distance and angle weremade using Kern Mekometer ME5000 and WILD
T3000, respectively.
The line between SR2 and SR9 was chosen to be a"baseline" .
The program for analysis is written with BASIC language for a personal computer. Main part of the program is cited from the survey textbook. This program
was so modified that we can calculate the many positions by using a small memory.
All error ellipses are smaller than the circles of radius 1 mm. However, including the error accompaniedwith setting of the tripod and the stand, the center
coordinates of the seal on the monuments agree withthe adjusted values within the error of ±2 mm.
Concluding remarks are as follows: 1) The survey
should be carried out before the building construction;2) The concrete pillar on which a survey instrument
is put is suitable for the fiducial point. Much time
was used for setting the tripod at the Japanese fiducial point; 3) When the survey network is dense, thedistance measurements are easy if using several reflectors. Many exchanges of reflectors are necessary whenusing a few reflectors; 4) A stand of height 1- 1.5 m isnecessary if the construction has started.
We made the second survey in October 1993. Now
this data are being analyzed.

RIKEN Accel. Prog. Rep. 27 (1993)

Field Measurements of SPring-8 Dipole Magnets
J. Ohnishi and M. Kawakami*
Eighty-eight dipole magnets will be installed in the
Spring-8 storage ring. Forty dipoles of them have already been delivered to Nishi-Harima SPring-8 construction site and their field measurements have finished except two to inspect the field performance. The
dipole magnet is iron-dominated one and has a lengthof 3090 mm and a gap height of 61 mm.I) The fieldmeasurements were done by measuring the integrated
magnetic fields JBds with an instrument called "LongFlip Coil". It has a two turns coil with a length of3855 mm and a width of 15 mm. The integrated fields
were measured by integrating the induced voltage during flipping the coil in about 0.7 seconds in the magnet
gap.2) Figure 1 shows a photograph of a dipole magnet
being measured with Long Flip Coil.

1

N0 '4
1
_ I : 1232 A
Bo=O.679T

1.1)005i~/~
0.11990--....,~\

7

0.11985· 30

30

open ,ide __X(mm)Fig. 2. Horizontal distribution of integrated fields along
beam direction. Average of the field strength was anominal value of 0.679 T.

13

u

12

E
<U
en

10
9

Q..

--

Total No. 38
rms 0.00028

11IS.....0

7

c:i

5
4

Z

6
3

2
1

-10

Fig. 1. A photograph of the SPring-8 dipole magnet measured with "Long Flip Coil".

I I

I

0

*

..---

!

j

15
14

Figure 2 shows a horizontal distribution of the integrated magnetic fields on the median plane as an example. A sextupole field found as a parabolic curve inthis figure was presented systematically for all dipoles
and its strength was smaller than the tolerant value(7 x 10- 4 at x = 20 mm).
In the measurements of fluctuation of the integrated
field strengths between magnets, a sample magnet
and a reference magnet were powered in series andmeasured alternately to confirm the stability of themeasurements. As the temperature of the measuring coil was found to affect the measured values in
pre-measurement, the temperature of cooling waterof magnet was decreased near the temperature of themeasurement room to suppress a temperature rise of
the measuring coil and the measuring time was kept

~

·8

-6

-4

'I
-2

I'I
4

. BL/BLo

Fig. 3. Histogram of integrated field strength for 38
dipoles.

constant. As a result, the stability of the measured values of the reference magnet was better than ±5 x 10- 5
during measurements of 38 dipoles. Figure 3 shows ahistogram of the integrated field strengths normalized
by the measured value of the reference magnet. The
fluctuation was 2.8 x 10- 4 in rms and small enoughcompared with the tolerant value of 5 x 10- 4 •References
1) SPring-8 Project Team: SPring-8 Project Part I, Facility
Design (1991). [Revised]
2) J. Ohnishi, H. Takebe, and S. Motonaga: RIKEN Accel.
Prog. Rep., 23, 167 (1989).

Ishikawajima Kogyo Co. Ltd.

145

RIKEN Accel. Prog. Rep. 27 (1993)

Field Measurements of SPring-8 Quadrupole Magnets
J. Ohnishi and N. Kumagai
The SPring-8 storage ring contains 480 quadrupole
magnets. All the quadrupoles will be measured withrespect to excitation curves , magnetic field lengths,
multipole fields, and positions of magnetic center.
An equipment called "Harmonic Coils" was designed
and manufactured. The principle of the measurement
and experimental results with a prototype were described in Ref. 1. Figure 1 shows a photograph of the
newly developed equipment. Harmonic coils are fixed
inside a cylinder made of fiberglass reinforced epoxy
resin which has a diameter of 80 mm and a length of1600 mm. Two kinds of coil configuration of four manufactured cylinders are shown as cross-sectional viewsof the cylinders in Fig. 2. The coil cylinder is inserted
in the magnet gap and fixed with bearing supports at
both sides. Magnetic fields are obtained by Fourier

Fig. 1. Harmonic Coil and SPring-8 quadrupole magnet.

Coi l1 : 50 Turns
Coil2 : 50 Turnsa) Twin CoilCoil! : 12 Tums
Coil2 : 24 Turnsb} Bucking Coilanalysis of the induced voltages measured while thecoils rotate with a speed of 30 rpm.
The strength of quadrupole field must be measured
in high reproducibility of better than 10- 4 to measure
the fluctuations between magnets. As the rotating radius of coil is changed due to the deformation in fixing
the coil cylinder, it is not easy to achieve this high reproducibility when a magnet is exchanged. In the twin
coil configuration in Fig. 2(a) , changes of the output
from the two coils were canceled out and the reproducibility was reached as good as about 5 x 10- 5 .
Multipole components appearing from error of themagnet production are measured with the bucking coilconfiguration in Fig. 2 (b). 2) As this configuration of
coils cancels the output from the main quadrupole
field, which is thousand times stronger than higher
multipole fields , accuracy of the measurement of themultipoles is improved. The suppression ratio of themain term was 4% in the produced coil.
The magnetic center is also measured with this measurement equipment. The accuracy should be better
than 20 j.Lm. The method of measurement of the magnetic center is as follows. The dipole component induced from the harmonic coil is in proportion to thedisplacement of rotating axis of the coil from the magnetic center , and the phase of the dipole component
against the quadrupole component presents the direction of the displacement. Calculating the position of
the displacement from the strength and the phase, therotating axis and the magnetic center are made coincided by moving the magnet with a computer cont rolled stage. Then the position of the magnetic center
is obtained from the deviat ion between reference pointsof the measurement equipment and the magnet .
Presently, development of the measurement device
for the displacement of coil axis from the reference
point in magnets and adjustment for improvement of
the accuracy are in progress.
References
1) J. Ohnishi and N. Kumagai: RIKEN Accel. Prog. Rep.,
26, 155 (1992).

Fig. 2. Cross sections of two types of coil cylinders. Coil
1 and coil 2 are connected in series for both types.

1462) "Magnetic Measurement and alignment", CERN Accelerator School Proc. edited by S. Thrner (1992).

RIKEN Accel. Prog. Rep. 27 (1993)

Construction of Power Supplies for SPring-8 SR Magnet
H. Takebe, N. Kumagai, J. Ohnishi, K. Kumagai, S. Matsui, and S. Motonaga
Ten power supplies for quadrupole magnets (QP)
and one power supply for sextupole magnets (SxP)
were made in March 1993 for the SPring-8 Storage
Ring. These PSs are set in the experimental hall until
the PS-room A is completed. I)
The cable routes between the magnets and cablerack and a cooling water distributing header system forthe magnets were designed. A proto-type cabling system for them was made in the previous 1 cell magnets
in the experimental hall this autumn (Fig. 1). Test
operation of QP with four Q-magnetswas done andcurrent ripple was measured. The stability was better
than 3 x 10- 5 .
A control sequence and interfaces for the power supply (PS) system were decided. Connection and control
test of the RIO-B for the PSs was done also. 2 ,3) A
pin assignment example of the interface between RIO(type-B) and power supply is listed in Table l.
Power supply's control command sequences and timing flow are also decided. The cyclic time for ADC readout strobe must be within 0.6 ms r-v 20 ms and those
for a DAC set will be within 0.4 ms r-v 100 ms. The
ADC data is transferred to the RIO card via a 16 bits
parallel signal.
A block diagram of the SxP is shown in Fig. 2.
A 33.3 kHz MOS-FET switching regulator system. is
piggy-backed by the 6th phase thyrister regulator. A
VME controlled remote I/O card is connected to this
PS using an optical fiber cable. 2 )Table 1. Status read pin assignment of the PS control.
pin
12
13

alb
a
b
a
b

status
DI-ComDI-ComDIO
DIlcontents+5 r-v 15 V
+5 r-v 15 V
ADC Data (LSB)ADC Data

21
22
23
24
25
26
27
28
29
30
31
32

a
b
a
b
a
b
a
b
a
b
a
b
a
b
a
b
a
b
a
b
a
b
a
b

DI6
DI7
DI-ComDI-Com
DIO
DIl
DI2
DI3
DI4
DI5
DI6
DI7
DI-ComDI-Com
DI8
DI9
DIlO
DIll
DIl2
DIl3
DIl4
DIl5
DI-ComDI-ComADC Data (MSB)+5", 15 V+5", 15 V
On/offLine Input
Local/Remote
Fault/Fuse
Over Curro
Over Volt
Temp.Err (Fan)Mag.InterLck+5 r-v 15 V
+5 r-v 15 V
Water Flow
Transistor /FuseOven Error
Polarity+
Fire/ Smoke
Grounded
ADC Strobe+5 r-v 15 V
+5 r-v 15 V

Fig. 1. Combination test of Q and S magnets, cabling and water header system.
Q-PS and SxP are seen behind.

147

A bending magnet PS (BP) is being constructed andwill be completed until next spring. An input transformer for 6.6 kV for this BP is located in an outeryard and connected by four sets of bus ducts for 24
phase rectifiers.
Twelve sets of steering magnet PS's are made andtested. Each steering magnet(St) is connected to one
PS. Thirty-six sets of the St-PS are mounted in one

cubicle and a DC source is supplied by one AC-DC
converter'!) Total number of the St-PS is 576.
Auxiliary (QA) PSs are designed and will be madein this winter.
Thirty-eight sets of skew Q-magnet power supply(SkP) system are now being designed. Ten or eight
SkP sets will be located in each of the A, B, C, D PS
rooms.

~~pfIL~~
,,
"

300A
781V

~

~

,

:,

To

1\

Mqm:t

I

____~~__r-~__~____~~-cSh~oort__~'_~
OCR

VME

Master RIO ---~~£!!..!~~-----~w;:::::=1;;-:-;;r~~nn1

Fig. 2. Block diagram of the SxP.

References
1) H. Takebe et al.: RIKEN Accel. Prog. Rep., 26, 157(1992) .

148

2) H. Takebe et al. : ibid. , p. 176.
3) H. Takebe et al. : ibid. , 25 209, (1991).

RIKEN Accel. Prog. Rep. 27 (1993)

Preliminary Network for SPring-8 Machine Group
H. Takebe, I. Kobayashi, T . Masuda, T. Nakamura, S. Fujiwara, and T. Wada
A preliminary network system was made for the
SPring-8 group (40 people) in the Harima construction site in April 1993.

ID.ter-Net ~---_~
j ___________ ,: Kyot~OV!~>.':-,

TISN.
Tokyo VOIV.

~~~---------------;----------..,AERI(Tokai Site)',•_______________--·----...~Rike~-(wai~iit;)--:

Router: (AGS+):• _ _ _______

Ten workstations, thirty personal computers and six
VME 1 ,2) computers are connected as the first step tothe (temporary) SPring-8 Local Area Network (LAN)'.....,..;'

~~U

,~:
until 9317 • J-_______________ •Super Digital Line 64kbps

ISDN
INS net 64-

NIT from 931Aug .

:SP;i~g:i -----------·~'P·~~.~i~-e-J·."lns--tt-u-te-o{m

"#'d.
UI

j

: Te1~:::V

~

,

,

: .~(ProteonP410q+).~~..: .. _ )".!oJo!~'!.~2QlJ

f NIT Ylinter F.

---f2I'~~:~~~:~~;~-1-1~~3~ - - - - - - - - - - - -- -~ -~~~~1~~2~1-

Motorola ~7

•

- - -

•

E=~==~=n~~~-.________~____-.____~Y~ell~o~w~C~M~le~________-.~~~~~P4100~,

Fig. 1. Computer network of the SPring-B storage ring building (Tentative stage).

using Ethernet TCP lIP protocol. Before end of July
1993, this LAN was connected to the RIEKN Wakosite through INS-64K (NTT) using a Router (CISCO:
CIS4000) as seen in the Fig. 1. In August 1993,
this LAN was connected to the RIKEN and J AERI
Tokai site via Kyoto University (Uji) and TISN 3 ) using NTT's SD-64K line.
Three sets of 8-port 1OBase-T HUB were connectedto the Yellow cable. This 10Base-T HUB 's 8 ports were
led to a modular jack (RJ-45) through 4 pairs of UTP
cable (EIA: Category-5, 1061A). A PDS 4 ) patch panel
system was introduced to an IDF box. From the IDF
patch panel to each room wall consent, two pairs of
the UTP cables were used for the 10Base-T , one pair
for the telephone line, and one pair for the Macintosh
Phone-net. Three RJ-45 jacks were assigned as shownin Fig. 2 and mounted in one consent panel. Eachroom has two wall jack consents. Four or six ports of
10Base-T HUB can be adopted to the Wall jack inside
a room, if it was necessary. These rooms will be usedby experiment user's groups in future.

8 wire UTP(EIA-5,106 A )Cable

Wall Jack Concent

1---1~~h

Apple
Talk
Ether

Telep oneFig. 2. lOBase-T HUB , Macintosh Phone-net and telephone cables are used.

References
1) T. Masuda et al.: RIKEN Aceel. Prog. Rep., 26, 174(1992).
2) H. Takebe et al.: ibid. , p. 177.
3) Tokyo Univ. Int. Sci. Network.
4) Premises Distribution System (Sanki Co. and AT&T).

149

RIKEN Accel. Prog. Rep. 21 (1993)

Measurement of Temperature Dependence of
HOM Frequencies in a Bell-shaped Cavity
H. Ego, M. Hara, Y. Kawashima, Y. Ohashi, T. Ohshima,
H. Suzuki,* I. Takeshita, and H. Yonehara*
Quality and current value of the beam in the storage ring of SPring-8 depend on beam instabilities. Intrinsic higher order modes (HOMs) in an RF cavity
excited by the beam are likely to cause coupled-bunch
instabilities. I ) Then characteristics of HOMs in a bellshaped RF cavity2) were measured and field distributions of them have been obtained with the bead perturbation technique. 3 ,4) Detuning HOM resonances fromthe instability conditions is one of methods for suppressing the instabilities. HOMs with high coupling
impedances have the high Q-value and the frequency
shift by more than 100 kHz is needed. Figure 1 showsa schematic diagram of controlling HOM frequencies
with two movable plungers. 4 ) The plunger 1 on theside of the cavity is used for shifting HOM frequencies
and the plunger 2 tunes the cavity to the accelerating
frequency, 508.58 MHz , within ±0.5 KHz.

to the network analyzer

a network analyzer. The network analyzer and theplungers were controlled by a computer with the GPIB
interface.
Data of TM110 mode was shown in this report sincethose of other HOMs were similar to each other.
Figure 2 shows frequency shifts of the TM 11 0 mode
as a function of the position of the plunger 1. The
frequency of TM110 mode changed at the rate of 12
KHz °C when the position of the plunger 1 was fixed.
Then the frequency was very sensitive t o the positionof the plunger 1 and the shift at the rate of about
50 KHz/mm was attained. The amount of frequency
shift was independent of the cavity temperature in thismeasurement. Similar data were obtained when theroles of two plungers were exchanged with each other.

N

o
o

>-

o
•

I
~ 765.0ut = 30 rC]
40
50
60

c:
Ql

~

764.5

~
o

~ 764.0~

I-

763.5 '---'---'--'--'---'--'---'-~'---'--~'---'---'----''--'--~'--'---'
-10
-5
O·
5
10
plunger position [mm)movable ~plunger 2 \M;Fig. 1. A schematic diagram of the two-plunger system.

The temperature of the cavity increased by about
20°C in operation of 100 kW RF power. 5 ) HOM frequencies change in accordance with the temperature.
The two-plunger system was tested for a prototype
cavity at various temperatures. We heated up the cavity with mantle heaters instead of RF power, since itis difficult to measure HOM frequencies while feeding
the RF power into the cavity.
The temperature of the cavity was set to 30, 40, 50,
and 60°C and controlled within ±0.5 DC. The cavity
was evacuated to about 10- 5 Pa to prevent oxidation.
Resonant frequencies of the cavity were measured with*
150

Japan Atomic Energy Research InstituteFig. 2. Frequency shifts of TMllO mode as a functionof the position of the plunger 1. The accelerating frequency was tuned to 508.580 MHz within ±0.5 KHz
by the plunger 2. The origin of the abscissa shows the
position of the inner surface of the cavity.

References
1) Y. Yamazaki, K. Takata, and S. Tokumoto: IEEE Trans.
Nucl. Sci. , 28, 2915 (1981) .
2) K. Inoue et al.: RIKEN Accel. Prog. Rep., 24, 162(1990).
3) H. Ego et al.: ibid., 26, 159 (1992).
4) H. Ego et al.: Proc. of 9th Symp. Accel. Sci. Technol.,p. 249 (1993).
5) H. Ego et al.: Proc. of 17th Linear Accel. Meet. in Japan,
p. 180 (1992).

RIKEN Accel. Prog. Rep. 27 (1993)

Test of Dummy Loads
Y. Ohashi, H. Ego, M. Hara, Y. Kawashima, T. Ohshima,
H. Suzuki,* 1. Takeshita, N. Tani,* and H. Yonehara*
Four 1.2 MW klystrons (E3786) from Toshiba Co.
are used to generate 508.58 MHz RF power to thestorage ring cavities in the SPring-8. Figure 1 shows
one section of the RF station. The RF power from a
klystron is fed to the eight bell shape single-cell cavities through a circulator and three stage magic-tees.
Reflected RF power is absorbed in two types of dummyloads , 300 and 50 kW ones. The 300 kW load is installed at the port #3 of a circulator which prevents
the harmful reflected power from going back into a
klystron. Four of them are to be used to absorb fullpower up to 1.2 MW in a klystron test. It is also used
to absorb power to a particular cavity, which is inoper- .
able by some trouble (we plan to disconnect this cavity
from the system and terminate by two loads). Seven of
the 50 kW loads are installed at the magic-tees, and it
is also used to absorb coming back power directly fromthe cavity as described in the next paragraph. Thesedummy loads consist of water-cooled-coaxial loads andwaveguide-to-coaxial transitions.

We chose 50 kW loads at the magic-tees and 300 kW
one at the circulator in consideration of above cases.
They are operational even for the beam current up to
200 rnA. These loads should stand, of course, for muchhigher transient reflected power.
We regards the RF leakage as a most important criterion in the selection process. In consideration of reliability and good shielding against RF leakage of the
300 k W loads, we selected them uniquely from thePremier Microwave of California, U.S.A. In order toexamine performance, we purchased three different 50
kW loads from Premier, Bird Electronic Co., U.S.A.,
and Nihon Koshuha Co.
Table 1. Specification.
param.\ maker(kW)

VSWR(max)

Premier Premier Bird N.K.
(300) (50)(50) (50)
1.2

1.1

1.1

1.1

Weight (kg)

50

34

7

54

Length (em)

380

92

50

86

Watel"flow(I/min)

45

230

42

50

Max. coolant

4.2

7

N.A.

10

press.(kgf/cm1)
Max RF

C7)

-80

-80

N.A. -80510

3

leakage (dBe)*of flanges

Accelerating cavities

Fig. 1. RF transmission system.

We estimate the RF powers absorbed in these loads
by considering only stationary reflection in the following two cases. Suppose we set a coupling coefficient f3
corresponding to the designed stored beam current of
100 rnA. The reflected power is about 4 kW from eachcavity without beam loading. This reflected power decreases with increasing beam current up to 100 rnA. In
another case, if the klystron power is not fed to a particular cavity which is inoperable, the reflected power
induced by the beam loading becomes about 14 kW.

*

Japan Atomic Energy Research Institute5

A specification of loads is listed in Table 1. Preceding to the installation, we examined all the loads at
the RIKEN-Wako test stand. Tests include low power
measurements of characteristics and high power measurements of temperature distribution, power reflection, and RF leakage. The reflected power from cavities has higher frequencies, so VSWR should be good
not only at 508 MHz but also at higher ones. Since a
low power measurement was done with a network analyzer through a coaxial-to-waveguide transition, it provided the characteristics of only two transitions near
508 MHz. Obtained VSWR of all the loads are lessthan 1.1. The result of high power measurements islisted in Table 2.
The 50 kW load from Premier shows very high temperature rise on the outer case. This is because waterflows inside the resistor but not between the resistor
and the outer case. Since this particular load has 10
flanges, a chance of RF leaking might be high becauseof the uneven tightening. A regulation on the RF leakage requires that electric field is to be 40 dBJ.L V jm
or below at 100 m away from the source or on thesite boundary. A measurement should be done to map
151Table 2. Result of high power measurement.
Parameter Premier

Premier Bird

N. K.

/company
Power

SO

SO

SO

80

18

13

.1

<.02S

<.02S <.02S

-60

-40

-40

300

(kW)

Max temp 36(load),61
rille (t:) (transition)
Reflected
power
(kW)

RFleak(dBm)-SOthe electric field with an antenna and a spectrum analyzer. In this measurement we used a close-field probe(Hewlett Packard 11940A) to get a reasonable estimate. Observed power of -40 dBm can be converted
to electric field, and the corresponding value is 152

152

dBJLV jm on the surface. Leakage was observed fairly
locally, so the active area (1.9 cm 2 ) of the probe is agood measure to estimate the field strength at a certain
distance. We expect about 20 dB below the limit in
the worst case with all the loads installed. Preceding
to the high power measurement a similar test was attempted at low power of 10 W, however, a fairly large
leak from an N-type connector interfered the meaningful measurement.
One practical problem arose in the 300 kW load that
we could supply only 200 Ijmin in the test stand because of a big pressure loss in the water line. This is
avoided by enlarging a diameter of the water connectors. Care also must be paid in the design of waterlines to minimize the pressure loss.
In conclusion all the tested loads satisfied our requirements in the short term test. A long term operation for a reliability check is to be done next.

RIKEN Accel. Prog. Rep. 27 (1993)

Test of 1.2 MW Circulator
T. Ohshima, H. Ego, M. Hara, Y. Kawashima, Y. Ohashi,
H. Suzuki,* 1. Takeshita, N. Tani,* and H. Yonehara*
In a storage ring of SPring-8, four 1 MW klystrons
are used to feed 508.58 MHz RF to the accelerating
cavities. Each klystron drives eight cavities. A circulator is inserted between the klystron and cavities
to protect the klystron from the reflected RF power.
Circulator transfers an RF power circularly from theport-l to the port-2, from the port-2 to the port-3 andso on. A klystron is connected to the port-I, the port-2
is connected to cavities, and the port-3 is terminatedby a dummy load.
We tested two 1.2 MW Y-type circulators made by
ANT corporation in Germany. A structure of the circulator is shown in Fig. 1. It has ferrite disks cooled .
by water at the junction of three wave guides. A static
magnetic field is applied to the ferrite for its premagnetization. This field is generated by two permanent
magnets mounted top and bottom of the wave guide of
the circulator. Each permanent magnet is surrounded
by a coil which is used for compensating the effectsof the fluctuation of temperatures of the cooling waterand/ or the ambience. The specification of the circulator is shown in Table 1.
The RF characteristic of the circulator was measured
with a calibrated network analyzer. The results wereas follows: The insertion loss was less than 0.1 dB, thecross section

top view

permanen~~i~gnet•________ .__ __:::

Port-2Ferrite Disk----------_ ..._- ----_..

Fig. 1. A top view and a cross section of the circulator.
Table 1. The specifications of the circulator.
frequency

508.58MtIz

20dB bandwidth±2%

insertion loss

<O.l5dBfOlwardpower(CW)

max.l.2MW

reverse power(CW)

max.600kW

VSWR

<1.2

flange*WR1800Japan Atomic Energy Research Instituteisolation was better than -25 dB, and the reflection
was less than - 25 dB, i.e. VSWR was less than 1.12.
The high power tests were done with a set-up as
shown in Fig. 2. The 1.2 MW klystron was connectedto the circulator port-l through a directional coupler(D.C.l). The port-2 was shorted with a short plate.
The port-3 was terminated by a 1.2 MW dummy load.

CD.C.2)

Fig. 2. A setup for the high power experiment.

Another directional coupler (D.C.2) was inserted between the port-3 and the dummy load. The worst
phase condition is that the H-fields of the forward
1.2 MW wave and the reflected 600 kW wave aresummed up in phase, which results in a largest energy loss at the ferrites. In this case the loss Ploss inthe circulator is proprtional to the square of H-field,
Ploss <X (yiP fwd + vip rft)2, where P fwd is a forward RF
power and P rft is a reflected power. We measured thepower loss in a condition of the total reflectIon of 875
kW at the port-2, which is equivalent to the forward
1.2 MW and reflected 600 kW. The loss was measured
as a function of the distance between the short plate
and the port-2. The step size was about 10 cm whichcorresponds to about 40 degrees of the RF phase. The
insertion loss was determined by measuring the dissipated energy in the circulator, i.e. a temperature riseof its cooling water.
Figure 3 shows the power of the reflected wave fromthe circulator measured at the D.C.1. The ratio of

8

i:

Q;
3:
~

6 1- ....- ..- ...- ..-.,-...----.....-.-,----.....-.-...- ...+-........- ....-.---+-...........~...............-j

'0

4 r

Q)

t5
Q)

'$

i

:

- ····.···········.· ...••••; .•••••• ..............•....' . •:;.m•••.••••..•..•• ;

·

• ••

.

~ _ _ _ . ; . _• •_ . _ _~

2 r ·m .............m... +. ___._._:i._._.____ + ____ -+. __ __.~

£I:

!

:e

O ~~~~~~~~-L~~~~~

o

200

400

600

Input Power (kW)

800

1000

Fig. 3. The reflected power from the circulator.
153

0.02
:::l

.~ 0.015

a..

--

u

~u

0.01

0.005
0

L--~.....L...~--.....l~~.....L....~--'--'-~~-L........~----.J

-10

o

10

20

30

40

position of short plate (em)50

Fig. 4. The ratio of the dissipated power at the circulator(Pcirc) to the input power (Pinput) as a function of theshort plate.

154

the reflected wave to the input power was less than
0.65% , which corresponds to that VSWR was 1.18.
Figure 4 shows the ratio of the dissipated power inthe circulator to the input power as a function of theposition of the short plate. The maximum power loss
at the circulator was observed when the short plate
was set at a distance of 24 cm from the port-2. The
insertion loss was less than 2.5%, i.e. 0.11 dB .
In conclusion, performance of the two circulators
satisfied our requirements.

RIKEN Accel. Prog. Rep. 27 (1993)

A Phase Lock System of 508.58 MHz Reference LineY. Kawashima, H. Ego, M. Hara, Y. Ohashi, T. Ohshima,
H. Suzuki,* 1. Takeshita, N. Tani,* and H. Yonehara*
Fundamental radio frequency (RF) of 508.58 MHz
generated by a synthesizer is delivered to four RFstations located in a storage ring and also to one RFstation in a synchrotron ring. 1 ) Instability of the phaseseriously affects the beam; therefore the phase must be
kept as precisely as possible in all RF -stations. We aregoing to control the precision of phase within ± 10 ofwhich value almost comes from the precision of a phasethe total system. The phase lock system and obtained
results are described here briefly.
First of all we explain the mechanism of a phase locksystem. An RF is transmitted from station (A) to (B)through a transmission line, for example, as shown in
Figs. 1 and 2. The RF signal received in the station (B)is divided into two. One is used there as a reference
signal, and the other is returned to the station (A)Next st(jonLocal use

508.58MHr---...+---------~1U"H'\............~

50758MHz

ADC

Fig. 1. Diagram of 508.58 MHz reference line.

through the same line. The transmission line is shrunkor expanded depending on the ambient temperature.
Consequently, the phase change of a returned 508.58
MHz-RF signal is amplified just twice, because the returned RF signal passes through the same transmission line. A phase lock loop (PLL) at the station (A)detects these phase variations by observing the phasedifference between the original and the returned signals, and adjusts a relative phase of the signal sent to(B) to keep the same reference phases at both stations(A) and (B). Thus the phases at the station (A) and(B) are always kept at almost the same angles. This is
the phase lock system.
A coaxial cable has been used for a transmission line,
for example, TRISTAN at KEK.2) In case of TRISTAN, 508.58 MHz-RF in the station (B) is divided into
two. One is used there, and the other is converted todetector currently existing. We have assembled various tools to confirm the phase lock system and tested
just half-frequency to identify a returned signal froman original one. Then the converted RF signal is returned to the station (A) through the same coaxial*

ReceiverTransmitter

Iso: Isolator
T : Terminator
C : Connector

M : Reflector
Co: Coupler

Fig. 2. Detail of the parts of transmitter and receiver.

cable. The returned RF signal is reconverted to theoriginal frequency with an RF doubler and comparedwith original one. In our case, the transmission line
uses an optical fiber instead of a coaxial cable. There
are two merits to use it. One is very small attenuationand the other is less interference between forward andbackward optical signals. So that we can deal with
only 508.58 MHz-RF and the total system becomes
simpler.
Our phase lock system consists of a PLL part, RFtransmitter part, transmission line and receiver part,

Japan Atomic Energy Research Institute155

as shown in Fig. 1. Every part of PLL comprises NIM
modules and the other consists of an electrical to optical (E/O) converter and an optical to electrical (OlE)converter, and an optical fiber. This performance wasalready reported elsewhere. 3 ) The RF optical signal
from an E/O passes through an isolator which protects
the E/O from the damage due to reflected light. The
RF optical signal is divided into two. One is used there
and the other is reflected by a mirror, as shown in Fig.
2. The PLL detects the phase difference between thetransmitted and reflected RF signals and makes thedifference small. Thus the total system is more compact compared to an old system with a coaxial cable.
We have tested the phase lock system with opticaldevices and had various troubles. For example, theterminators shown in Fig. 2 are connected with I-typeconnectors where phase is largely changed according to
the temperature. Thus we connected an optical fiber
to a terminator by the method of melting bonding,and then the phase variation got negligible small in156

this part. The other trouble is that the ratio of optical division at a transmitter and receiver parts in Fig.
2 is 50% in each branch and the total light returnedto the transmitter is decreased largely. Consequently,
S IN ratio got bad. In order to improve the SIN ratio,in particular, in the returned RF -signal, we changed
the optical division ratio to 20% and 80% in the partof coupler, so that signal levels from O/Es in Fig. 2
become the same. We are improving these points andthe phase stabilization is kept within ±0.5° as long as
the change of room temperature at the location of a
PLL is maintained at the level of ±l°C.
References
1) Y. Ohashi et al.: RIKEN Accel. Prog. Rep., 26, 178(1992).
2) M. Ono et al.: KEK Int. 87-6 (1987) and references
therein.
3) Y. Kawashima et al.: RIKEN Aceel. Prog. Rep., 26,179(1992).

RIKEN Accel. Prog. Rep. 27 (1993)

A Direct Counter of 508.58 MHz
Y. Kawashima, H. Ego, M. Hara, Y. Ohashi, T . Ohshima, H. Suzuki,*
I. Takeshita, N. Tani,* and H. Yonehara*In the SPring-8, 508.58 MHz radio frequency used inboth storage and synchrotron rings is a fundamental
frequency. A direct counter for 508.58 MHz has beenrequired for beam handling, setting single-bunch modefor storage and synchrotron rings, beam monitoring,and so on. The technical difficulty has so far prohibited the realization of a fast counter. But we haverecently realized a fast counter running in the region
below 600 MHz. We briefly describe the performanceof the 508.58 MHz-counter.
The requirements to the 508.58 MHz-counter are as
follows;(1) a direct counter of 508.58 MHz ,(2) a non-stop counter which counts from one toa preset value (A) set manually, then automatically
resets and restarts without miscount , because 508.58
MHz is a continuous wave,(3) generation of a single output pulse as a timing
signal at the point of preset value (B) , which is set
with an external computer (Preset number (B) mustbe smaller than or equal to the number (A)).
Unfortunately there has been no commercialized ICs
which work stably over 600 MHz. Even if a fast counter
was required, one had to order special integrated cir
cuits (ICs) made of GaAs to a semiconductor produc-

NIM output

tion company. The price of such ICs would become
very expensive. Fortunately, commercialized ICs arerecently produced by MOTOROLA, we can easily getthem. We found an 8-bit synchronous binary counter,
MCI0EOI6, which counts up to 700 MHz and designed
a direct counter of 508.58 MHz with it. Its block diagram is shown in Fig. 1. The most difficult pointin the design is that the counter has to be made areset every 2436 counts which correspond to the harmonic number of the storage ring. The number, ofcourse, is different in case of the synchrotron. After reset , the counter must be restarted within a very
short time of 1.966 nsec which comes from one countof 508.58 MHz. Total propagation delay time as tovarious gates including reset and recovery time is estimated to be 1.775 nsec. Next pulse comes only 191
psec later (1.966 nsec - 1.775 nsec = 191 psec). An
actual circuit board consists of 6 layers to suppress
an oscillation due to high frequency of 508.58 MHz.
To make paths between ICs as short as possible, ICs
were placed on both surfaces of a board. After various
troubles, we could construct a 508.58 MHz-counter. It
was very difficult to check such a fast counter. We
invented a sophisticated method to check it. 1) It wasverified that the 508.58 MHz-counter worked well up
to 600 MHz without any trouble such as miscount.
This counter is not a final version. Final one will
have to be equipped with an input port for external
reset by a computer control to make a set time zero
to all 508.58 MHz-counters used in the SPring-8. It is
impossible to add an external reset-port in the present
508.58 MHz-counter. Because the extra gate of IC
must be added in the circuit for an external reset-port,
total propagation delay time becomes longer than one
cycle of 508.58 MHz. Our solution to overcome thisproblem is to utilize a newly available IC instead of
MCI0EOI6. In the very near future a new version of
508.58 MHz-counter will be constructed.
References

Fig. 1. Block diagram of a 508.58 MHz-counter.

*

1) H. Suzuki et al.: 9th Symp. on Accel. Sci. and Tech., p.
252 (1993).

Japan Atomic Energy Research Institute.

157

RIKEN Accel. Prog. Rep. 27 (1993)

Transmission Test of the Timing Signal for the SPring-8
H. Suzuki,* H. Ego, M. Hara, T. Hori ,* Y. Kawashima, Y. Ohashi,
T. Nagafuchi ,* T. Ohshima, N. Tani,* and H. Yonehara*
To operate the accelerator complex of the SPring-8
facilities, two systems for the timing coordination arenecessary. The first system is associated with beamtransfer from the linac to the synchrotron. The second system is associated with beam transfer from thesynchrotron to the storage ring. The RF system of thelinac is operated by an oscillator at the frequency of2856 MHz. The RF systems of the synchrotron and thestorage ring are operated by another oscillator at thefrequency of 508.58 MHz and at the harmonic number of 672 and 2436 , respectively. Since the width ofshort pulsed beam from the gun of the linac is 1 nsec
at full width half maximum (FWHM) and the time
width of each RF bucket in the two rings is 2 nsec, thetiming accuracy required for beam transfer from thelinac to the synchrotron and the synchrotron to thestorage ring must be less than 100 psec to suppress
the beam loss due to the synchrotron oscillation of theinjected beam. For single bunch beam operation, it
is necessary to select anyone of the 2436 buckets as
the single filled bucket in the storage ring into which
the bunched beam from the synchrotron is transferred.
Two concepts for the timing systems are being considered. One concept uses a synchronous timing table
which has low jitters (lower than 100 psec) and theother utilizes a phase control loop which has the accuracy of lower than 10. We had to choose the synchronous timing table, because there was no correlation between both frequencies of 2856 MHz and 508.58
MHz. The transfer line of the timing signal consists ofan optical fiber and EO JOE (electrical to opticaljvice
versa) transmitter and receiver which have low jittersand low dependence on temperature. The time jitteris a serious problem in transmitting a beam effectively,
because the beam is transported in the rigid beam line
at the speed of light and the timing accuracy from thelinac to the synchrotron almost depends on the jittersof the transfer line and the gun of the linac. And thetiming accuracy of the synchrotron to the storage ringis easily achieved by comparing the RF phase between
the two rings.
The jitters of a short-pulsed beam were measured
with the gun of the linac. Obtained results are described.
(1) Optical Fiber and EOjOE
The timing signal generator for the gun trigger issituated in the control station of the synchrotron. The
transfer line from the synchrotron to the gun is about
200 m long. Because the jitters of the timing signal are
required to be less than 100 psec, the optical fiber and*158

Japan Atomic Energy Research Institute

EO JOE which have low jitters are used for the timing system. The optical fiber (DTS-M02) which has
low dependence on temperature is made by Sumitomo
Electric Industries. The EOjOE (model 3510A and
4510A) which have high performance at high frequencies up to 3 GHz are made by ORTEL corporation.
(2) Old Transfer System of the Timing Signal
Figure 1 shows a block diagram of the old timing system for the prototype linac of SPring-8. The time jitters between the trigger signal (pulse generator, DG535
in Fig. 1) and the electron beam emitted from thegun following the signal (wall-current monitor, C.T.
in Fig. 1) were measured by using the old timing system. The electron beam from the gun was measured
by the wall-current monitor. This system made by
Mitsubishi Electric corporation is a black box. The
optical fiber and the EOjOE are used in this system.
But DTS-M02, 3510A and 4510A are not used in thissystem.

Fig. 1. The block-diagram of the old timing system.

Ch . 2
1 .5 12 ~'olt5/div
T "nebase=
500 p s/ d iv
Delta W,ndo= 378.0 0 mVoll 5I,) l n.jo," I= - 1 .89 0 0
Vo Il s
Del ta 'l.
0. 0 0 0 /.
Upper
0.00 0 /.
De 1 t ~ T" . 00000 sStar',
42.300 0 ns
# S5mples = 1000~

OffsetDela y=Window

2~- 4.788 Volt s
42. 08130 n 5-2. 2 68 0

Voll s

Lower

0.000

S top

42.300 0 ns

Tri gger un Ext e r nal at Pos· Edg e at/.

31 . 00 m'Jolts

Fig. 2. The jitters of the old timing system.

Figure 2 shows the jitters of the old timing system.
Standard deviation of the jitters is 170 psec.
(3) New Transfer System of the Timing System
Figure 3 shows a block diagram of the new timing
system. The optical fiber and the EOjOE are replacedwith DTS-M02 , 3510A and 4510A. To reduce the jitters caused by the dependence of the pulse height, aconstant fraction discriminator (CFD:ORTEC model935) is used after the EjO receiver. To minimize thejitters, the external delay, the threshold voltage andthe walk voltage of the CFD were optimized to 2 nsec,-20.3 m V and 0.3 m V, respectively. The jitters at thispoint were reduced from 77 psec to 27 psec by the CFD.
After this signal is amplified to a level of 9 V, the 9V signal is used for the trigger of the grid pulser of

Ch. 2
2 . 484 Volts/di'lT,mebase= 500 psidi'J
Del ta Windo= -232· 87 mVol t5~hndow I= -7.2967 VoltsDe I t a I.
65.2 7 I.
Upper
89.35 X
60.0
pS
De It -= T
Sta r t2.87667 uS: Sampl,,,
500
~lean
= 2·87664 us

OffsetDela y~=-9.999 Volts
2.87500 u s

W,nd ow 2 = - 7.06 38

Volts

t.

Lower

24 . 07Stop

2.87661 us

Sigmar",gger on External at Pos. Edge at

29 .9

ps

100.0 mVolts

Fig. 4. The jitters of the new timing system.

Fig. 3. The block-diagram of the new timing system.

the gun. Figure 4 shows the jitters of the beam current
wave form for the trigger signal. Standard deviationof the jitter is 30 psec.
The old and new timing systems for the gun of thelinac were tested. The new timing system meets the
specification of low jitters which must be less than 100
psec. A test using a pulse generator which has a fasterrisetime will be planned in the next year, and the jitterswill be lower than 30 psec.

159

RIKEN Accel. Prog. Rep. 27 (1993)

Control of SPring-8 SR Klystron Test Bench
S. Fujiwara, T. Masuda, and T. WadaA VME system with LynxOS 1 ) is planned to be
used in the control system of the SPring-8 storage ring(SR). We tested the VME system for the control of
the klystron test bench and evaluated its hardware andsoftware. We also examined the influence of noise on
the VME system.
The test bench of the klystron is similar to thatdesigned by KEK 2 ) and it has an interface with
CAMAC. The VME system was connected to the
klystron test bench through Interface (I/F) Box (Signal Conditioner) which conforms signal levels of VME
I/O boards to those of the interface of the klystrontest bench. The VME system is Motorola Delta LA.
The CPU board is MVME147SA-l with MC68030.
Three DI boards (PENTLAND MPV910) , a DO board(Digital DOUT2) and an ADC board (PENTLAND
MPV906) were inserted into the VME system. The
operating system is LynxOS. Test programs were written in C language. Figure I shows a schematic

110 board access programsby the shared memory or by device drivers

Fig. 1. Schematic diagram of the test programs.

diagram of the test programs. Programs rfbani (towatch status), rfban2 (to measure analog), rfban3,4(to control) and rfmenu (to select menu) are application programs. Programs kpi-kpil (corresponding toconnectors for using the shared memory) and kpLdrvkp 1Ldrv (corresponding to connectors for using device
drivers) are subJoutine programs. Programs dout2(DO set) , mpv910 (DI read) and mpv906 (AI read)are I/O board access programs by the shared memory. Programs dout2drv.o (DO), m910drv.o (DI) andm906drv.o (AI) are I/O board access programs by device drivers. 3 )160

The test programs using the shared memory successfully controlled the klystron test bench except forthe pulse-train control by rfban3,4. When the VME
system sent pulse-train signals for increasing the voltage of the klystron test bench, the voltage increased
and decreased alternately. We checked the followings
to get the causes for this: Firstly, we thought that
the LED in the I/F Box did not radiate light as current was small. We measured the current of the I/F
Box and found that the current was right as designed.
Next, we thought that the cables between the I/F Box
and the klystron test bench got out of order. Thosecables are made of flat cables which are bent like an
S-word. The ends of the cables are furnished with theLED's. We found that a cross-talk happened when using the cables. We checked the cables and confirmedthat they had no short circuit. We then thought that
this cause was that signal lines were too close to eachother. When the signal line for decrease was not connected, the increase signal had no problem; the increase of the voltage corresponded to the number oftransmitted pulses. But when we sent the decreasesignal under the same condition as above, the voltageof the klystron test bench was increased. The phenomenon showed no change either by separating thesignal lines from each other or by exchanging the flat
cables for twisted pair cables which were successfully
used in the CAMAC system.
We verified the followings by this test. The klystrontest bench was successfully controlled by the VME system using either of device drivers and the shared memory, except for the pulse-train control. We concluded
that the I/F Box had a problem of way about DO(pulse-train). We have not yet figured out the causesof this problem. The VME system was not influenced
by either noises from the IVR (inductive voltage regulator) or those that were generated when the interlock
for off of a high-tension occurred.
References
1) T. Masuda, T. Nakamura, T. Wada, and Z. Wang:
RIKEN Accel. Prog. Rep., 25, 240 (1991).
2) National Laboratory for High Energy Physics.
3) T. Masuda, T. Nakamura, H. Takebe, and T. Wada:
RIKEN Accel. Prog. Rep., 26, 174 (1992).

RIKEN Accel. Prog. Rep. 27 (1993)

Performance Test of Energy Analyzer for Photoelectrons
Produced by SR Irradiation
K. Yano, K. Watanabe, H. Sakaue, and S. H. Be
We have successfully done measurement of the photodesorption yields of gases desorbed from an OFC(oxygen-free copper) model chamber by using photon
beams with the critical energy of 26 ke V from the accumulating ring (AR) of TRISTAN at KEK.l) Measurements of energy distributions of photoelectrons are alsoplanned at KEK to investigate desorption mechanisms.
The plan of outline has been reported in Ref. 2. For
that purpose an apparatus is prepared, which consistsof an energy analyzer, a magnetically shielded vacuum
chamber with mumetal sheets and a pumping system.
This magnetic shielding reduces the geomagnetic fieldof ca. 0.03 mT to nearly zero and enables us to analyze electrons of lower energy less than a few e V. Theenergy analyzer is a double focusing electrostatic type.
Previous to energy analysis of photoelectrons the performance test of the energy analyzer was performed bypassing secondary electrons which were emitted froma silicon surface by electron bombardments. Figure 1
shows the sectional plan of the hemispherical analyzer
with the mean sphere radius of 36.5 mm. Other dimensions are given in Fig. 1. Main specifications of
the analyzer are as follows;crochannel plate charged particle detector (MCP) are
schematically illustrated in Fig. 2. A three-element,
cylindrical einzellens, whose focal length is adjustableto ca. 10 cm, is mounted to the entrance aperture of theanalyzer in oder to image a point source of electrons
directly into the analyzer entrance aperture without
alteration of the original electron energy spectrum. To
obtain an energy spectrum in this experiment, the analyzer is operated in the constant transmission energy
mode, that is to say, input energy range is scannedwith some predetermined ~ V, where ~ V is the potential difference between the sector electrodes. Potential of the middle electrode of the einzel lens has tobe adjusted to compensate the chromatic aberrationof the electrostatic lens in this mode. Energy-analyzed
electrons are measured by the MCP composed of dual
channel plates, the gain of each plate being several
thousand. By the way, the above-mentioned operationand data acquisition will be controlled by a computerat a remote place in the experiment at KEK. The assembly of the analyzer including the einzel lens andthe MCP is put in an electrostatic shielding box andthen installed in the magnetically shielded measurement chamber. 2 )

h~

IE

1j
T

rT

Rl

I1

R2

R - 36.5
Rl - 32.S
R2 - 40 .S

9-38. 1h-24 .6
j -1.6<-33.3(m m)

Fig. 1. Sectional plan of electrostatic energy analyzer.

Acceptance angle 0.002 sr
Resolution 0.4% for 0.05 cm diameter aperture
0.8% for 0.1 cm diameter aperture
Operating Temperature ambient, bakable to
400°C
Construction materials oxygen-free copper, sapphire,
stainless steel,alumina.
The electric connections of the analyzer and a mi-

Fig. 2. Schematic diagram of measurement system.

An example of energy spectra of secondary electrons obtained by a performance test of the analyzer
is demonstrated in Fig. 3 when energies of bombarding primaries are 200, 300, and 400 V. In conclusion
we confirmed from this result that the analyzer works
normally up to the energy less than a few eV without
suffering from the geomagnetic field. In addition wecan analyze the energy of photoelectrons up to 600 eVusing our present apparatus.
161

Computer-controlled operation and a data acquisition system are in preparation.

1.2

0 .8
0.6

References

0.4
0.2

6
Enetgy(eV)1012Fig. 3. Energy spectra of secondary electrons emitted
from Si surface by electron bombardment.

1621) K. Watanabe, T. Hanasaka, Y. Hirano, H. A. Sakaue, K.
Yano, S. Yokouchi, and S. H. Be: RIKEN Accel. Prog.
Rep., 26, 163 (1992).
2) H. A. Sakaue, K. Watanabe, K. Yano, T. Hanasaka, andS. H. Be: ibid., 25 , 233 (1991).

RIKEN Accel. Prog. Rep. 27 (1993)

Outgassing Rate Measurement of Braided Wire
K. Watanabe, K. Hayashi, and S. H. Be
We measured the outgassing rate of a braided wire
before and after baking for about 24 hours by meansof a so-called throughput method.
The measurement apparatus is schematically shownin Fig. 1. 1 ) The surface area of a sample chamber is
0.196 m 2 . The conductance of the orifice between thesample chamber and pump side chamber is 2.15 x 10- 3
m 3 /s for N2 at 22 cC.

(Pure N2 Gas)
Turbo

Pump Side Chamber(Down-Side)
Orifice

Experimental results of the outgassing rates as afunction of pumping time are shown in Fig. 3. The origins of the pumping time before and after baking are
the starting point of evacuation of chambers and thatof cool down. Because the outgassing rate is strongly
influenced by temperature, the rate after baking is decreased with an increase of time. The cooling timerequired to reach room temperature after baking is a
few hundred minutes.
The outgassing rates before and after baking are approximately 1 x 10- 6 Pa·m 3 /s and 5 x 10- 10 Pa.m 3 /s,
respecti vely.

(cp5.05 X to.5)

10

3

10-4

····~······· .. ····· .. ····1······.. ····· ..

······r··..·······......

B~FORE BtING
10- 5

~

"'e

•.i······..······_··r······. . ··

/I:S

e::.
t.t:l 10- 6
r-

Fig. 1. Measurement apparatus.

The braided wire, made of OFHC (oxygen free copper), consists of three cylindrical strata woven fromwires of 0.18 mm in diameter (Fig. 2) and its lengthis 3.2 m. The total surface area of wires is 2.0 m 2 .
The braided wire was cleaned using freon in an ultrasonic cleaner. The measurement procedure has been
described elsewhere. 1 )-<~c.:I 10-7~enen-< 108
~

::>
0

10

9

lO- lD
1

10

100

1000

10000

TIME (min)Fig. 3. Outgassing rate of braided wire.

References
Fig. 2. Structure of braided wire.

1) T. Hanasaka et al.: RIKEN Aceel. Prog. Rep., 26, 167;
169; 171 (1992).

163

RIKEN Accel. Prog. Rep. 21 (1993)

Design of Beam Position Feedback Systems for
SPring-8 Storage Ring
K. Kumagai
The stability of the photon beams is one of the critical parameters for the low emittance ring, SPring-8.
The main disturbing sources affecting beam stability
are: (1) machine floor deformation induced by sunlight and temperature; (2) deformation of magnets andgirders due to the temperature change of cooling water or air; (3) ground vibrations induced by seismic
motion, compressors, cooling water pressure, etc.; (4)power supply ripples and drift. In order to stabilize
the photon beam, the electron (positron) beam must
be stabilized in a few J..Lm. For this purpose, two typesof feedback system will be equipped in the SPring-8
storage ring: static closed orbit feedback and fast local bump feedback.
The static closed orbit feedback system is used forthe reduction of the long term drift or rather low frequency vibrations of the beam position. The 288 beam
position monitors (BPM) are installed in the ring andthe same numbers of vertical and horizontal correctors
are provided. The resolution of the BPM is about 10
J..Lm and the maximum kick angles of correctors are 1.0
mrad for horizontal plane and 0.5 mrad for vertical.

The orbit motion will be corrected in every minute.
For the beamlines with the tight beam stability requirement, a fast local bump feedback system will be
added (Fig. 1). In each beamline the system has twoor three photon beam position monitors which measure the deviation in angle and position of the beamand two sets of four corrector magnets that create thebumps for the horizontal and vertical plane. With afour-magnet bump it is possible to independently control both the position and the angle of the beam. The
resolution of the photon-BPM will be about 1 J..Lm andthe kick angles of correctors are about 50 J..Lrad. The
frequency range of the feedback system will be up to
70 Hz. As the fast response is needed for the feedback
loops, digital signal processor (DSP) boards are used
to give the proper corrector strengths from the photonBPM information. The systems also provide the cancellation of the deviations of beam position induced bychanges of magnet gap width of insertion devices.
Detailed design of the feedback circuit is now inprogress.

ID Gnp Imformntion
DSP

1 + - - - - - - - VME

v-t=t==:

I

Benmline
Control

Power
Supply-Photon Benm............... - ....... .......... ..
~V

Ptloton Monitor 3

ID

Correctors
Photon Moni tor I

Photon Monitor 2

Fig. 1. Diagram of local bump feedback system.

164

~

VI.

RADIATION MONITORINGRIKEN Accel. Prog. Rep. 27 (1993)

Measurement of Activities Induced by 135 MeV lu 20Ne
Incident on an Iron Target with the Activation Method
N. Nakanishi, S. Nakajima, S. Fujita, K. Tanaka,* T. Takagi,** and M. Watanabe*
In designing accelerator facilities, it is indispensable
to have accurate data for the neutron flux producedby high energy beams andlor neutron production crosssections. Therefore, a series of measurements for theneutron yield have been carried out for 135 MeV luvarious incident particles on a thick iron target withthe activation method.
Here, the activity induced in metals by neutrons pr~
duced by 135 MeV lu 20Ne beams incident on a thickiron target is briefly presented. Seven metals of C, AI,
Fe, Co, Ni, In, and Au were used as neutron detectors.
These metal detectors were placed at scattering anglesof 0, 30, 60, 90, 120, and 140 degs. Gamma rays were
measured after irradiation. Details of experiment aredescribed elsewhere. 1 )Figure 1 shows the angular dependence of induced
activities in the detector by various nuclear reactions.
The activity basically represents the product of aneutron-activation cross section and the neutron number produced by an incident particle. The reactions
and characteristics of detectors are also given in Ref.
1.
Hereafter, the activity will be unfolded using reaction cross sections, and the neutron flux will be eval-

Q)
()

I

't 10 - 24

I

I

I

----------

ro

--e--

.e-

~ 10- 25~----0---------'-.;~~---------0--~.........

..........

~.-- -=-----6----------~

10 -29
-30

o

30

60

90

120

C(n.2n)AI(n,a)Fe(n,p)Co(n ,a)Co(n.2n)Ni(n,2n)Ni(n,p)In(n,n')Au(n,g)Au(n,2n)Au(n,4n)150

Angle(deg)Fig. 1. Angular distributions of activities by neutron induced reactions. The neutrons are produced by 135
MeV lu 2°Ne beams incident on a thick iron target.

uated and a further mechanism producing neutrons in
the target will be examined.

*

References
1) N. Nakanishi et al.: Proc. 9th Symp. on Accel. Sci. andTech., Tsukuba, p. 425 (1993).

Faculty of Science and Technology, Chuo Univ.

** Fukuda Giken
165

RIKEN Accel. Prog. Rep. 27 (1993),-ray Spectrum from Iron Targets Bombarded by Accerelated Ions
S. Nakajima, N. Nakanishi, S. Fujita, K. Tanaka,* and T. Takagi**
A series of experiments with activation foil has been
continued to obtain secondary neutron spectra fromiron targets bombarded by various accelerated ions. 1)
A lot of ,-ray spectra from the activated foil were obtained in these experiments. We could get from these
spectra information about produced neutrons. As an
example, we showed in the last issue that significant
presence of neutrons with energies larger than 40 MeV
was easily observed in the reaction of 135 Me V lu nitrogen ions with an iron target. 2 ) There is also a report that neutrons whose enegy is up to 220 MeV
were identified by the ,-ray analysis in the similar
experiments. 3)
In those experiments iron targets were used only to
produce neutrons, and so , rays from them were notmeasured. But expecting that ,-rays from the targets offer some information about nuclear reactions,
we measured them incidentally after each experiment.
In the case of above experiment with 135 MeV lu nitrogen ions , we used an iron target of 12 mm in thickness
and obtained a specrum as shown in Fig. 1. From thefigure we could identify various nuclei such as Sc, V,
Cr, Mn, and Co. Similar spectra were obtained with
135 MeV protons and 135 MeV lu deuterons as incident
particles, and nuclei of V, Cr, Mn, and Co were also
observed. The spetra were slightly different among thecases of protons , deutrons, and nitrogen ions, but thediscrepancy was small.

LOG~------------------------------------~

MeV

Channel number

Fig. 1. ,-ray spectrum from an iron target irradiated by
135 MeV lu nitrogen.

In the case of the experiment using proton beam,
we used a stack of iron foil and blocks for the target as shown in Fig. 2. We expected that we could
get information from the ,-ray spectra of each foil orblock about what reactions took place and what radioactive nuclei were produced in each part, or how was*

Faculty of Science and Engineering, Chuo Univ.

** Fukuda Giken
166

Fig. 2. Schematic diagram of target array used in the caseof proton incident.

LOG
0 .5 Iochannel number

4096

Fig. 3. ,-ray spectra from a) an iron target no. 2 and b)
no. 3.

distribution of a dose rate along the iron target, andso on. Slight difference was seen, for example, between
Fig. 3(a) and 3(b). But this experiment was a preliminary one and we measured the ,-rays from the target after long-hour irradiation that was necessary forthe activation-foil experiment. Therefore intensities ofradiations from each iron foil and block were strong.
Consequently, the dead time of the counting system
was long and then the energy resolution was poor. ,rays from a nucleus having a short life-time disappear
if we wait until the time when the intensity of radiation becomes week enough. Then, it is difficult toobserve a difference in detail among these spectra withthis experimental set up.
A rivised experiment, optimizing parameters suchas counting rate, irradiation time, beam intensity, target's thickness and its number, is necessary to be done
to clearly identify the difference of these spectra.

References
1) N. Nakanishi et al.: This report, p. 165.
2) S. Nakajima et al.: RIKEN Accel. Prog. Rep., 26, 183(1992).
3) O. Wenxin Li et al.: Private comunication.

RIKEN Accel. Prog. Rep. 27 (1993)

Shielding Effect of the Concrete Wall between
El and E2 Rooms
S. Nakajima
There are a neutron and a 'Y dose monitoring detectors in every radiation laboratory in the Nishina
memorial building. Data of radiation level observedwith these detectors in each room are transported to acomputer every moment and stored in its disk memory.
In order to get some information about radiation'shielding, I examined the data stored during experiments to measure neutron flux in the El radiation
room. The experiments had been done in a scatteringchamber set almost in the center of the room. 1) An
iron target was put at the center of the chamber andbombarded by accelerated beams.
At an upper position of a side wall of the El room,
there are a neutron and a 'Y dose monitors as shown in
Fig. 1. When equipments and instruments arranged in
the room are neglected, this room is considered to besymmetric in right and left with regard to the direction of the accerelated beams. Therefore, I can assume
that these monitors are located on the opposite wall,that is, at a point A in Fig. 1. After all there would
be a concrete wall of 1.5 m thick between two sets ofmonitors in El and E2 rooms. A difference between
the simultaneously observed values with monitors in
E1 and E2 can be considered approximately to denotedirectly a shielding effect of the concrete wall.

J

culations using a program ANISN, the neutron dose
rate decreases to 3.7.10- 3 with this wall in the case of
135 MeV /u nitrogen,2) about one order of magnitudelarger than the observed value.
Table 1. Dose rate (ILSV /h) observed by the area monitors
in E1 and E2 together with a ratio E2/E1. The numbersof the incident particles are not the same in three cases.
Incident particle(135 MeV /u)Neutron dose rate
E1 vault
E2 vault
ratio E2/E1, dose rate
E1 vault
E2 vault
ratio E2/E1

ProtonDeutronNitrogen

30000
4
1.3.10- 4

10000
2
2.10- 46000
1.5
2.5.10- 4

15000
3
2 . 10- 4

3000
1.5
5.10- 4900
0.8
9.10- 4

There are two problems. First, the neutron monitors have almost no sensitivity to the neutrons whoseenergies are more than rv 20 MeV. But in this case thedifference between the observed and calculated ratios
E2/E1 becomes larger if corrections of this effect are
done, because its contribution to the observed value ofa neutron level in E1 is larger than that in E2. Next,a reflection from the walls and a floor was consideredin the calculation but the effect of various equipments .
was not included. In the case of 135 MeV nitrogen,measurements had been done to see the contributionof reflection using a rem counter. The result was thatit became nearly 60% of total neutron dose rate at aright angle from the target in El room. 2) Then, even if
the component of reflection is excluded assuming that
it is completely from the equipments in the room, monitored values in E1 decrease only by a factor of about
2.

10m

,

Fig. 1. A diagram showing a settled position of monitors
and the scattering chamber.

Above estimation is very rude, to be sure, but it isnecesarry to try the calculation by ANISN again bychanging an adopted model and parameters.
References

Table 1 shows that neutron and 'Y dose rates decreaseto rv 10- 4 with the concrete wall. According to cal

1) for instance, T. Shikata et al.: RIKEN Accel. Prog. Rep.,
25, 250 (1991).
2) T. Shikata: Private communication.

167

RIKEN Accel. Prog. Rep. 27 (1993)

Leakage Radiation Measurements in the Ring Cyclotron Facility
S. Fujita, N. Nakanishi, S. Nakajima, T. Takagi,* K. Tanaka,** M. Watanabe,** and T. Inamura
The radiation safety control system has worked
steadily this year, so as to enable us to make radiation monitoring continuously and automatically.
From March 22 to 23 and from July 28 to 29, experiments were carried out with 135 MeV /u
and
2oNe10+ beams (highest energy/nucleon) at intensities
of about 7 and 60 pnA. The beams were stopped at thetarget point A in the experimental vault El. Leak-age radiation of neutrons from E1 was measured withfour neutron dose rate meters , TPS-451S's (Aloka).
The beam current was read at the target A andrecorded with a personal computer through a beam integrator ORTEC 439. Dose rates were normalized withrespect to that at 1 pJ.LA. Figures l-(a), (b), and (c)show the target point A and positions where leakage
radiation was measured in this experiment. Results

HI

]

I

~1\1

- - - - - - - - - - - --,

lD

~

(2)

(3)

a,

(4)(S)

(6)

I

(7)

L -_ _....l

\

(a)

(9)
(10)

El

(b)

(c)

Fig. 1. Partial layout of the RIKEN Ring Cyclotron facility where the leakage radiation measurement was made.
(a) Part of basement 2nd floor; (b) Part of basement 1st floor; (c) Part of ground floor. Leakage-radiationdose measuring points are denoted by the number in parentheses. The monitoring position in the computerroom is denoted by x.

Table 1. Dose rates of neutron leakage radiation from atarget point A in the experimental vault El. (see Figs.
1-(a), (b), and (c)).
Measuringdale

Sep:28,1991

Oct 4,1991

Oct 5,1992

Mar.23,1993

Ju1.28,1993

12C6+

14N7+

DeuteronProton2°Ne10+2432

242

AcceleralCd

particle
Measured
posilion
(I)

25.4

0.51

0.86

0.012

0.51

(3)

11.8

18.5

0.61

12.3

(4)

56.5

139

5.82

21.3

(5)

70.2

81.8

692

35.1

89.8

(6)

62.8

81.2

109

13.2

31.4

(7)

431

530

541

509

327

87.5

188
1054

39.9

465

79 .6
427

18.9

(9)

88.6

211

( 10)

460

560

626

67 .8

367

(8)

*

1017

(2)

(II)

2.49

2.32

3.73

2.14

1.59

(12)

6.33

5.38

6.62

0.3

3.93

(13)

1.95

2.22

2.29

0.09

1.81

Fukuda Giken** Faculty of Science and Technology, Chuo University

168

are summarized in Table 1 together with a previous
report. I)
This year, the radiation level in the controlledarea has been much less than the safety limit (0.3
mSv /week). Leakage of neutrons has been recordedwith a monitor in a ground-floor computer room justabove a bending magnet that guides beams from theRing Cyclotron vault to the distribution corridor. This
radiation level, however, is far less than the safety limit(50 J.LSV /year) required at the boundary of the facility.
No leakage of f rays and neutrons was detected withenvironmental monitors set outside the building in thisperiod.

References
1) S. Fujita, N. Nakanishi, T. Shikata, K. Ikegami, T.
Takagi, I. Sakamoto, and T. Inamura: RIKEN Accel.
Prog. Rep., 25, 284 (1991).

RIKEN Accel. Prog. Rep. 27 (1993)

Residual Activities in the Ring Cyclotron Facility
S. Fujita, K. Tanaka,* M. Watanabe,* N. Nakanishi, and T. Inamura
Residual activities were measured at various points
in the Ring Cyclotron facility after almost every beamtime and during the overhaul throughout the year. In
the following we describe significant residual activities
observed.
From August 5 to 8, the last experiment in the springterm was carried out with an 11 B 5 + beam of 70 MeV lu
in the experimental vault E6.
A routine overhaul was made in August, and thedose rates due to residual activities of the Ring Cyclotron and the injector AVF cyclotron were measured
on Aug. 4 and 24. Those results are shown in Figs. 1
and 2 together with detection points. The residual

Fig. 1. Detection points around the RIKEN Ring Cyclotron: an electrostatic deflection channel, EDC; amagnetic deflection channel 1, MDC1; a magnetic deflection channel 2, MDC2; a main differential probe 1,
MDP1; a main differential probe 2, MDP2; a main differential probe 3, MDP3. Indicated numerials are dose
rates in units of j1SV Ih.

activities at the Ring Cyclotron and injector AVF cyclotron have increased compared with those of a previous report!) because beam intensity has been increased
since last year.
In the period from Oct. 16, 1992 to Sep. 30, 1993,
residual activities were measured along the beam lines
with a portable ionization chamber. The detection
points above 20 j.LSV jh are shown in Fig. 3. Table
1 summarizes the detected dose rates with measured
dates. The maximum dose rate was 350 j.LSv jh at the
point j (the production target chamber of RIPS) in the
beam distribution corridor. We could not measure thedose rate there immediately after the beam time thisyear.

Fig. 3. Layout of the RIKEN Ring Cycrotron facility
as of 1993. Monitoring positions are denoted by x.
Detection points of residual activities on the beam lines
are denoted by alphabets.
Table 1. Summary of the residual activities measured
along the beam lines with an ionization chamber survey meter. Alphabets indicate the detection points in
Fig. 3.
Detection

Detected

point

dose rate

Date

Faculty of Science and Technology, Chuo University

dose rate

Dare

Feb. 1,1993

350

Sep.9,1993

33

Feb. 1, 199327

Oct. 19,1992

72
43

Sep. 9.1993

65*

Detected

point(IlS v/h)(Il Sv /h)Fig. 2. Dose rates detected inside the injector AVF cyclotron. They are given in units of j1SV Ih . .

Detection

Scpo 9,1993

85

Oct. 19.1 992

28

Oct. 19,1992

90

Oct. 19. 1991

48

Scp.9.1993

130

Sep. 9,1993

250

Mar.2 6,1993

200

Sep. 9.1993

60

Oct.26,1992

100

Nov. 2.1992

60

Oct.26. 1992

85

Nov. 2,1992

100

Feb. 1.1993

References
1) S. Fujita, S. Okamoto, H. Matsumoto, K. Tanaka, N.
Nakanishi, and T. Inamura: RIKEN Aceel. Prog. Rep.,
26, 186 (1992).
169

VII. LIST OF PUBLICATIONS
1.

Accelerator
physics

development

andaccelerator

M. Hara and Y. Miyahara: "Large Synchrotron Facility SPring-8", Engineering, No. 60, p. 18 (1993).
J. L. Laclare, A. Ropert , L. Farvacque, H. Tanaka, J.
Payet, P. Nghiem, and A. Tkatchenko: "Study of the
Emittance Reduction in the ESRF Storage Ring",
ESRF /MACH-LAT-93-08 (1993).
H. Ego, M. Hara, K. Inoue, Y. Kawashima, Y. Ohashi,
H. Suzuki, I. Takeshita, and H. Yonehara: "Statusof the SPring-8 RF System" , Int. J. Mod. Phys. A(Proc. Suppl.), 2A , 709 (1992).
H. Ego, M. Hara, K. Inoue, Y. Kawashima, Y. Ohashi,
H. Suzuki, I. Takeshita, and H. Yonehara: "HighPower Test ofRF System for SPring-8", ibid., p. 712.
M. Hara: "4th Int. Conf. on Synchrotron Radiation
Instrumentation", J. Atomic Energy Soc. Jpn. , 34,
58 (1992).
T. Nakagawa, T. Kageyama, M. Kase, A. Goto, andY. Yano: "Upgrade of RIKEN 10 GHz Electron Cyclotron Resonance Ion Source Using Plasma Cathode
Method", Jpn. J. Appl. Phys. , 32L, 1335 (1993).
T. Kubo, M. Ishihara, N. Inabe, H. Kumagai, I.
Tanihata, K. Yoshida, T. Nakamura, H. Okuno, S.
Shimoura, and K. Asahi: "The RIKEN Radioactive
Beam Facility", Nucl. Instrum. Methods Phys. Res. ,B70, 309 (1992).
Y. Yano: "Recent Achievements at the RIKEN Ring
Cyclotron", Proc. 13th Int. Conf. on Cyclotrons andTheir Applications, Vancouver, p. 102 (1992).
T. Nakagawa, T. Kageyama, M. Kase, A. Goto, andY. Yano: "Plasma Cathode Method for RIKENECRIS", ibid. , p. 365.
Y. Yano: "RIKEN Accelerator Research Facility(RARF)", Proc. Joint Italian-Japanese Meet. on
Perspectives in Heavy Ion Physics, Catania, p. 1
(1993).
H. Ego, M. Hara, K. Inoue, Y. Kawashima, Y. Ohashi,
H. Suzuki, I. Takeshita, and H. Yonehara: "Statusof the SPring-8 RF System", Proc. 3rd Joint Symp.
Synchrotron Radiation Sources, Pohang, Korea, p.
293 (1992).
H. Ego, M. Hara, K. Inoue, Y. Kawashima, Y. Ohashi,
H. Suzuki, I. Takeshita, and H. Yonehara: "HighPower Test of Single Cell Cavities for SPring-8",
Proc. 17th Linear Accelerator Meeting in Japan,
Sendai, p. 180 (1992).
M. Hara: "Characteristics of Photon at SPring-8",
Proc. SPring-8 Workshop on Atomic Physics at High
Brilliance Synchrotron Radiation Facilities, March,
1992, Himeji, p. 203 (1992).
Y. Yano: "Current Status and Future Scope on the
RIKEN Accelerator Research Facility" , Proc. 9th
Symp. on Accel. Sci. and Technol., Tsukuba, KEK,
p. 23 (1993).

A. Goto, T. Kageyama, M. Kase, S. Kohara, M.
Nagase, T. Nakagawa, K. Ikegami, O. Kamigaito,
N. Inabe, I. Yokoyama, J. Fujita, T. Kawama, andY. Yano: "Status of the RIKEN AVF Cyclotron",ibid., p. 59.
T. Masuda, S. Fujiwara, T. Nakamura, H. Takebe, andT. Wada: "Development of Device Drivers Embedded in Real Time OS for SPring-8 SR Control Systern", ibid., p. 79.
T. Nakagawa, T. Kageyama, Y. Miyazawa, E. Ikezawa,
M. Hemmi, M. Kase, A. Goto, M. Nagase, and Y.
Yano: "Status of the RIKEN ECRIS's", ibid., p. 95.
T. Nakagawa, T. Kageyama, A. Goto, N. Inabe, O.
Kamigaito, M. Nagase, T. Chiba, M. Hemmi, M.
Kase, Y. Miyazawa, E. Ikezawa, and Y. Yano: "Design of an 18 GHz ECRIS for the RILAC", ibid., p.
98.
S. Kohara, A. Goto, Y. Miyazawa, T. Chiba, M.
Hemmi , Y. Chiba, E. Ikezawa, M. Kase, and Y.
Yano: "Development of a Second-Harmonic Buncher
for the RILAC", ibid., p. 157.
K. Ikegami, J. Fujita, T. Kubo, N. Inabe, T.
Kageyama, M. Kase, A. Goto, Y. Yano, H. Sakai,
H. Okamura, N. Sakamoto, T. Uesaka, S. Ishida,
H. Otsu, T. Wakasa, and K. Hatanaka: "Development of the RIKEN Atomic Beam Type Polarized
Ion Source", ibid. , p. 214.
O. Kamigaito, A. Goto, Y. Miyazawa, T. Chiba, M.
Hemmi, M. Kase, and Y. Yano: "Design of a Variable
Frequency RFQ Linac for the RILAC", ibid., p. 220.
H. Ego, M. Hara, Y. Kawashima, Y. Ohashi, T.
Ohshima, H. Suzuki, I. Takeshita, and H. Yonehara:"Higher Order Modes of the Single Cell Cavity for
the SPring-8", ibid. , p. 249.
H. Suzuki, Y. Kawashima, Y. Ohashi, H. Yonehara,
H. Ego, N. Tani, T. Nagafuchi, T. Hori, T. Oshima,
and M. Hata: "Characteristics of RF Reference andTiming Signal Distribution for SPring-8", ibid. , p.
252.
N. Nakanishi, S. Nakajima, S. Fujita, H. Matsumoto,K. Tanaka, and T . Takagi: "Measurement of Neutron Yield Produced by 135 MeV/nucleon H2 and
2D Beams Incident on a Thick Iron Target with theActivation Method", ibid., p. 425.
M. Kase: "Development of a Beam Phase Monitor
with a Micro-Channel Plate for the RIKEN Ring Cyclotron" , ibid., p. 474.
M. Hara: "Synchrotron Radiation", The Reviews ofLaser Engineering, 21, 126 (1993).
M. Hara, T. Nakamura, T. Takada, and H. Tanaka:"U se of Long Straight Sections of SPring-8", Rev.
Sci. Instrum., 63, 355 (1992).
M. Hara, S. H. Be, I. Takeshita, and T. Nanba: "Extraction of Infrared Radiation from SPring-8", ibid.,
p. 1543.

171

T. Kusaka, K. Inoue, and M. Hara: "Design of RF Cavities for the 8 GeV Synchrotron Radiation Facility I.
Design, Fabrication, and RF Measurements of Model
Cavities", Sci. Papers J.P. G.R., 68, 28 (1992).
T. Kusaka, T. Yoshiyuki, K. Inoue, I. Takeshita, and
M. Hara: "Design of RF Cavities of the 8 Ge V Synchrotron Radiation Facility II. Design of RF Cavities
for the SPring-8 Storage Ring", ibid., p. 35.
M. Hara: "Light Source Performance of SPring-8" , SR
Science and Technology Information, 3, No.9, p. 2
(1993).
M. Hara: "SPring-8, A Challenge to Highly Brilliant
Photon Source", Symp. on Charged Particle OpticsData of 119th Meeting, July, 1992, Tsukuba, p. 1
(1992).
S. H. Be: "8 GeV Synchrotron Facility", Vac. J., 29,
6 (1993).
2.

Nuclear physics and nuclear instrumentation

H. Sato: "Systematics of Isotope Production Rates:
Fission Products and Their Barrier Penetration" , in
Abstact of the Second Meeting on Nuclear Incineration JAERI-memo 05-191, p. 46 (1993).
H. Kudo, M. Fujie, T. Tanase, M. Kato, K. Kurosawa,
H. Sugai, H. Umezawa, T. Matsuzaki, and K.
Nagamine: "Preparation of Pure Tritium for a Liquid D2/T2 Target of Muon Catalyzed Fusion Experiments", Appl. Radiat. Isot., 43, 577 (1992).
H. Toki, D. Hirata, and I. Tanihata: "Nuclear Properties Far from the Stability Line in the Relativistic
Mean Field Theory", Hyperfine Interact., 74, 113(1992).
K. Asahi, H. Okuno, H. Ueno, H. Sato, J. Kura,
T. Kubo, T. Nakamura, N. Inabe, A. Yoshida, Y.
Ohkubo, M. Adachi, T. Ichihara, M. Ishihara, T.
Shimoda, H. Miyatake, N. Takahashi, D. Beaumel,
D. J. Morrissey, and W. -D. Schmidt-Ott: "Spinoriented Projectile Fragments: the First Application
to g-Factor Measurement", ibid., 75, 101 (1992).
K. Asahi: "Fragment Spin Polarization and Its Application", Inst. Phys. Con! Ser., No. 132, p. 183(1993).
K. Matsuta, A. Ozawa, Y. Nojiri, T. Minamisono, M.
Fukuda, S. Momota, T. Ohtsubo, S. Fukuda, K.
Sugimoto, I. Tanihata, K. Yoshida, K. Ornata, J. R.
Alonso, G. F. Krebs, and T. J. M. Symons: "NMR
on Beta-emitting Fragment 43Ti", ibid., p. 229.
T. Takeda, K. Nagamine, Y. Yamazaki, R. Kadono,
K. Ishida, M. Kamimura, Y. Yamazaki, and M.
Mizumoto: "Progress of Muon Science", J. Atomic
Energy Soc. Jpn., 34, 1098 (1992).
K. Nagamine: "Muon Catalyzed Nuclear Fusion andCold Nuclear Fusion", ibid., 35, 27 (1993).
A. Ferragut, Y. Gono, T. Murakami, T. Morikawa, Y.
H. Zhang, K. Morita, A. Yoshida, M. Oshima, H.
Kusakari, M. Sugawara, M. Ogawa, M. Nakajima, S.
Mitarai, A. Odahara, E. Ideguchi, T. Shizuma, M.
172

Kidera, J. G. Kim, S. J. Chae, B. J. Min, and H.
Kumagai: "A New High-Spin Isomer in 145Sm", J.
Phys. Soc. Jpn., 62, 3343 (1993).
H. T. Duong, C. Ekstrom, M. Gustafsson, T. T.
Inamura, P. Juncar, P. Lievens, I. Lindgren, S.
Matsuki , T. Murayama, R. Neugart, T. Nilsson,
T. Nomura, M. Pellarin, S. Penslin, J. Persson, J.
Pinard, I. Ragnarsson, O. Redi, H. H. Stroke, J.
L. Vialle, and the ISOLDE Collaboration: "Atomic
Beam Magnetic Resonance Apparatus for Systematic Measurement of Hyperfine Structure Anomalies(Bohr-Weisskopf Effect)", Nucl. Instrum. Methods
Phys. Res., A325, 465 (1993).
Y. Futami, T. Mizota, Y. H. Pu, Y. Honjo, K. YuasaNakagawa, H. Toyokawa, S. M. Lee, K. Furutaka, T.
Murakami, J. Kasagi, K. Yoshida, and T. Nakagawa:"Performance of a Phoswich Detector Composed ofThin Plastic and Thick BaF 2 Scintillators", ibid.,
A326, 513 (1993).
Y. Hasegawa, H. Yuta, F. Suekane, T. Kondo, Y.
Unno, H. Iwasaki, Y. Sakai, Y. Watanabe, T.
Tanimori, K. Kaneyuki, L. Soso, T. Doke, A. Hitachi,
T. Ito, K. Hasuike, K. Masuda, E. Shibamura, andT. Takahashi: "Photoionization of Dopants in Liquid
Argon-Xenon Mixture", ibid., A327, 57 (1993).
N. Ishida, T. Doke, J. Kikuchi, K. Kuwahara, T.
Kashiwagi, M. Ichige, K. Hasuike, K. Ito, S. Ben, A.
Hitachi, Y. H. Qu, K. Masuda, M. Suzuki, M. Kase,
T. Takahashi, M. Chen, S. Sumorok, M. Gaudreau,and E. Aprile: "Measurement of Attenuation Lengthof Scintillation Light in Liquid Xenon" , ibid., p. 152.
M. Suzuki, T. Takahashi, H. Kumagai, M. Ishihara,and H. Kobayashi: "A Single-Neutron Sensitive
Camera Based upon a Proportional Scintillation
Imaging Chamber", ibid., A333, 484 (1993).
M. Tohyama and E. Suraud: "Stochastic and Deterministic Solutions of the 2-D Boltzmann Equation",
Nucl. Phys., A549, 461 (1992).
W. Q. Shen, J. Peter, G. Bizard, R. Brou, D.
Cussol, M. Louvel, J. P. Patry, R. Regimbart, J. C.
Steckmeyer, J. P. Sullivan, B. Tamain, E. Crema, H.
Doubre, K. Hagel, G. M. Jin, A. Peghaire, F. SaintLaurent , Y. Cassagnou, R. Legrain, C. Lebrun, E.
Rosato, R. MacGrath, S. C. Leong, S. M. Lee, Y.
Nagashima, T. Nakagawa, M. Ogihara, J. Kasagi,
and T. Motobayashi: "Components of Collective
Flow and Azimuthal Distributions in 40 Ar + 27 Al
and 40 Ar + 58Ni Collisions below 85 MeV lu", ibid.,
A551, 333 (1993).
M. Kato, W. Bentz, K. Yazaki, and K. Tanaka: "A
Modified Nambu-Jona-Lasino Model for Mesons andBaryons", ibid., A551, 541 (1993).
S. Hirenzaki, H. Toki, and I. Tanihata: "Proton Elastic
Scattering with 9Li and 11 Li and its Halo Structure",
ibid., A552, 57 (1993).
K. Sumiyoshi, D. Hirata, H. Toki, and H. Sagawa:"Comparison of Relativistic Mean Field Theory andSkyrme Hartree-Fock Theory for Finite Nuclei andNuclear Matter", ibid., p. 437.
1. Tanihata: "Radioactive Beam Facilities and Their
Physics Program", ibid., A553, 361 (1993).
J. Chiba, D. Ashery, H. Ito, K. Kimura, T. Yu. Kiselev,
S. Koda, K. Miyano, T. Murakami, T. Nagae,
Y. Nakai, M. Nomachi, S. Sawada, M. Sekimoto,T. Suzuki, K. H. Tanaka, M. K. Viasov, and Y.
Yoshimura: "Enhancement of Subthreshold Antiproton Production in Deuteron Induced Reactions",
ibid., p. 771c.
K. Tanaka, W. Bentz, and A. Arima: "EOS andFermi-Liquid Properties in the 1IN Expansion of a
Relativistic Many-Body Theory", ibid., A555, 151(1993).
S . . Kox, J. Carbonell, C. Furget, T. Motobayashi,
C. Perrin, C. Wilkin, J. Arvieux, J. P. Bocquet,
A. Boudard, G. Gaillard, M. Garc;on, L. Ghedira,
G. Guillaume, F. Merchez, D. Rebreyend, and J.
Yonnet: "Cross Section and Deuteron Analyzing
Powers of the 1H( d,2p)n Reaction at 200 and 350
MeV", ibid., A556, 621 (1993).
Y. Gono, T. Murakami, T. Morikawa, A. Ferragut, Y.
H. Zhang, K. Morita, A. Yoshida, H. Kumagai, M.
Oshima, H. Kusakari, M. Sugawara, M. Ogawa, M.
Nakajima, S. Mitarai, A. Odahara, E. Ideguchi, T.
Shizuma, M. Kidera, J. C. Kim, S. J. Chae, and B.
J. Min: "High-Spin Isomers and High-Spin Isomer
Beams", ibid., A557, 341c (1993).
D. Cussol, G. Bizard, R. Brou, D. Durand, M.
Louvel, J. P. Patry, J. Peter, R. Regimbart, J. C.
Steckmeyer, J. P. Sullivan, B. Tamain, E. Crema, H.
Doubre, K. Hagel, G. M. Jin, A. Peghaire, F. SaintLaurent, Y. Cassagnou, R.· Legrain, C. Lebrun, E.
Rosato, R. MacGrath, S. C. Jeong, S. M. Lee, Y.
Nagashima, T. Nakagawa, M. Ogihara, J. Kasagi,
and T. Motobayashi: "Charged-Particle Calorimetry of 40Ar + 27AI Reactions from 35 to 65 MeV lu",
ibid., A561, 298 (1993).
K. Nagamine: "Experiments on Muon Catalyzed fusion", in Perspectives of Meson Science, eds. T.
Yamazaki, K. Nakai, and K. Nagamine, North Holland, Amsterdam, p. 383 (1992).
K. Nagamine and K. Ishida: "Towards Advanced
Muon-Beam Production", ibid.,p. 441.
C. -B. Moon, M. Fujimaki, S. Hirenzaki, N. Inabe, K.
Katori, J. C. Kim, Y. K. Kim, T. Kobayashi, T.
Kubo, H. Kumagai, S. Shimoura, T. Suzuki, and 1.
Tanihata: "Measurement of 11 Li + P and 9Li + P
Elastic Scatterings at 60 MeV", Phys. Lett., B297,
39 (1992).
G. Bizard, R. Bougault, R. Brou, J. Colin, D. Durand,
A. Genoux-Lubain, J. L. Laville, C. Le Brun, J. F.
Lecolley, M. Louvel, J. Peter, J. C. Steckmeyer, B.
Tamain, A. Badala, T. Motobayashi, G. Rudolf, and
L. Stuttge: "From Binary Fission to Multifragmentation in the Decay of Heavy Excited Nuclei", ibid.,
302B, 162 (1993).
H. Ejiri and H. Toki: "Search for Exotic Nuclear Tran-sit ions with Nuclear Instability," ibid., B306, 218(1993).
T. Shigetani, K. Suzuki, and H. Toki: "Pion Structure
Function in the Nambu and Jona-Lasino Model",ibid., B308, 383 (1993).
B. M. Young, D. Bazin, W. Benenson, J. H. Kelly,
D. J. Morrissey, N. A. Orr, R. Ronningen, B. M.
Sherrill, M. Steiner, M. Thoennessen, J. A. Winger,
S. J. Yennello, 1. Tanihata, X. X. Bai, N. Inabe, C.B. Moon, S. Shimoura, T. Suzuki, R. N. Boyd, andK. Subotic: "Strong Isomer Production in Fragmentation Reactions", ibid., B311, 22 (1993).
J. Miller, G. F. Krebs, J. Panetta, L. S. Schroeder,
P. N. Kirk, Z.-F. Wang, W. Bauer, W. Benenson,
D. Cebra, M. Cronqvist, B.-A. Li, R. Pfaff, T.
Reposeur, J. Stevenson, A. Vander Molen, G. Westfall, J. S. Winfield, B. Young, T. Murakami, T.
Suzuki, and 1. Tanihata: "Mass Dependence of Pion
Production in Heavy Ion Collisions Near, but Below
Threshold", ibid., B314, 7 (1993).
D. Hirata, H. Toki, 1. Tanihata, and P. Ring: "Systematic Study of Sr Isotopes in the Relativistic Mean
Field Theory", ibid., p. 168.
A. A. Korsheninnikov, K. Yoshida, D. V. Aleksandrov,
N. Aoi, Y. Doki, N. Inabe, M. Fujimaki, T.
Kobayashi, H. Kumagai, C.-B. Moon, E. Yu.
Nikolskii, M. M. Obuti, A. A. Ogloblin, A. Ozawa,S. Shimoura, T. Suzuki, 1. Tanihata, Y. Watanabe,
and M. Yanokura: "Experimental Study of 8He +p Elastic and Inelastic Scattering", ibid., B316, 38(1993).
O. Kamigaito, H. Sakaguchi, M. Nakamura, S.
Hirata, H. Togawa, T. Nakano, M. Yosoi, M. Ieiri,
T. Ichihara, H. M. Shimizu, Y. Nakai, and S.
Kobayashi: "Inelastic Scattering of Protons, 3He,
and 4He at 30 MeV I Nucleon from 166Er and 176Yb
and Quadrupole Moments of the Optical Potential" ,Phys. Rev. C, 45, 1533 (1992).
T. Ohnuma, K. Hatanaka, S. 1. Hayakawa, M. Hosaka,
T. Ichihara, S. Ishida, S. Kato, T. Niizeki, M. Ohura,
H. Okamura, H. Orihara, H. Sakai, H. Shimizu, Y.
Tajima, H. Toyokawa, H. Yoshida, and M. Yosoi:"( d, 2He) Reactions at Ed=260 MeV as a Possible
Probe to Nuclear Spin-excitation", ibid., 47, 648(1993).
T. Suzuki, M. Fujimaki, S. Hirenzaki, N. Inabe, T.
Kobayashi, T. Kubo, T. Nakamura, Y. Watanabe,
and 1. Tanihata: "Search for a Bound State of a
Negative Pion and Neutrons in 18 0 + Be Collisions",
ibid., p. 2673.
N. Fukunishi, T. Otsuka, and 1. Tanihata: "NeutronSkin and Proton-Skin Formations in Exotic Nuclei
Far from Stability", ibid., 48, 1648 (1993).
S. Kim and S. Ohta: "QCD Thermodynamics with
Eight Staggered Quark Flavors on a 163 x 6 Lattice",
Phys. Rev. D, 46, 3607 (1992).
H. Toki, D. Hirata, 1. Tanihata, K. Sumiyoshi, and Y.
Sugahara: "Relativistic Many Body Theory for Un173

stable Nuclei", Proc. China-Japan Joint Nucl. Phys.
Symp. on Recent Topics on Nuclear Physics, Nov.
1992, Tokyo, p. 206 (1992).
H. Suganuma and T . Tatsumi: "Chiral Symmetry and
Quark-Antiquark Pair Creation in the Strong ColorElectromagnetic Field", Prog. Theor. Phys., 90, 379(1993).
K. Nagamine: "Slow J.L+ and I_e Beam Production
and the Next Generation of Muon Science" , Springer
Proc. Phys. , 59, 55 (1992) .
K. Nagamine: "Condensed Matter Studies with Polarized Bound Negative Muons", ibid. , p. 73.
H. Sato: "An Application of Multi-Precision Arithmetic in Physics: Nucleus as a Canonical Ensemble" ,Trans . Inf. Proc. Soc. Jpn. , 34, 391 (1993).
T. Murakami, Y. Gono, A. Ferragut, Y. H. Zhang,
K. Morita, A. Yoshida, M. Ogawa, M. Nakajima,
B. J. Min, J. Kumagai, M. Oshima, T. Morikawa,
M. Sugawara, and H. Kusakari: "High-spin IsomericState in 144Pm" , Z. Phys. , A345 , 123 (1993).
K. Nagamine: "Muon Science Research with Pulsed
Muons at UT-MSL/KEK" , ibid., C56, 215 (1992).
K. Ishida and K. Nagamine: "Muon Facility Plans Towards JHP" , ibid. , p. 296.
3.

Atomic and solid-state physics

Y. Kanai , H. Sakaue, T. Kambara, Y. Awaya, N.
Nakamura, S. Kitazawa, M. Nagat a, S. Ohtani, H.
Suzuki, T. Takayanagi, T. Nabeshima, T . Negishi ,and K. Wakiya: "Doubly-Excited States of He-likeand Be-like Ions in Highly-Charged Ions", AlP Conf.
Proc. , 274, (6th Int. Conf. on the Physics of Highly
Charged Ions) , p. 63 (1993) .
Y. Kanai, T. Kambara, M. Oura, Y. Zou, S. Kravis,
and Y. Awaya: "Binary Encounter Peaks for 0° Electrons in Collisions of 0.8 MeVI amu Biq+ with H2 andHe", ibid. , p. 135.
H. Shibata, T . Tonuma, T. Matsuo, H. Kumagai , and
H. Tawara: "Multiply Charged Ions from Gaseousand Frozen CF 4 and SF 6 Produced by Energetic
Heavy Ion Impact", ibid. , p. 335.
Y. Matsuo, H. Maeda, and M. Takami: "Gas Phase
Ion-Molecule Reaction in an RF Ion Trap: Reactivityof the 5d Transition Series of Metal Ions (Lu+, Hf+,
Ta+ , and W+) with O 2'' , Chern. Phys. Lett., 201 ,
341 (1993).
R. Kadono and R. F. Kiefl: "Muon Diffusion in Solids" ,Defect and Diffusion Forum, 95/98, 279 (1993) .
E. Vagi: "Solid Krypton Precipitates in Kr-Implanted
Aluminium" , ibid., p. 38l.
Y. Matsuo, H. Maeda, and M. Takami: "High Res~olution Laser Spectroscopy of Metallic Atoms andMolecules: Storage of Singly and Double Charged
Ions Transferred from Externally Generated Laser
Plasmas", Hyperfine Interact., 74, 269 (1992).
Y. Awaya and T. Kambara: "Studied of Atomic
Physcis at RIKEN" , Int. J. PIXE, 2, 233 (1993).
174

N. Toshima: "Role of Projectile Continuum St ates in
the Ionization of Atomic Hydrogen by High-Energy
Ion Impact", J. Phys., B25, L635 (1992).
H. Tawara, T. Hayaishi, T. Koizumi, T . Matsuo, K.
Shima, T. Tonuma, and A. Yagishita: "Productionof Multiply Charged Xe i + Ions via Photoionizationand Exitation in L-edge Region", ibid. , p. 1467.
N. Toshima: "Convergence of the Perturbation Series
for High-Energy Electron Capture", ibid. , B26, L281
(1993).
K. Ando, Y. Zou, S. Kohmoto, T. Kambara, Y. Awaya,
T. Tonuma, T. Niizeki, and S. Tsurubuchi: "Lifetimes of 2p5 3p and 2p 5 3d Levels in Ti XIII", J. Spectrosc. Soc. Jpn., 41, 370 (1992) .
T. Minowa, H. Katsuragawa, and H. Komatsu: "Resonance Ionization Spectroscopy of Molybdenum andits Application to a Pure Ion Source", Nucl. Instrum.
Methods Phys. Res., B72, 255 (1992).
T. Okada, K. Asai , N. Yamada, T. Matsumoto, Y.
Yamada, and Y. Kodama: "57 Fe Mossbauer Studies
of YBa2 (Cul-xFex) 408", ibid. , B76, 338 (1993) .
M. Sataka, M. Imai , Y. Yamazaki, K. Komaki, K.
Kawatsura, Y. Kanai, and H. Tawara: "Binary PeakElectrons Observed at 0° for 2-4 MeV lu Fq+, Si q +and Ni q + Ions in Collisions with a He Target", ibid. ,B79, p. 8l.
R. Kadono: "Progress in Experimental Studies ofMuon Diffuion", in Perspectives of Meson Science,eds. T. Yamazaki , K. Nakai , and K. Nagamine,
North Holland, Amsterdam, p. 113 (1992 ).
H. Qui, A. Kosuge, H. Nakai, S. Yugo, M. Hashimoto,G. Safran, B. Pecz, B. Barna, E. Vagi, and H.
Maruyama: "Effect of Bias-Voltage on Structuraland Physical Properties of Ni Film DC SputterDeposited on Si(100) and Si0 2", Proc. 2nd Int.
Symp. on Sputtering and Plasma Processes, ed.
E. Kusano and H. Kitahara, ISSP'93 Committee,
Tokyo, p. 207 (1993) .
E. A. G. Armour, D. M. Lewis, and S. Hara: "Calculations of the Deexcitation Rate of dtJ.L within the
Muonic Quasimolecule (dtJ.L) dee" , Phys. Rev. A, 46 ,6888 (1992).
H. Tawara, T. Tonuma, H. Kumagai, and T . Matsuo:"Ions Produced from Condensed CO Target under
Energetic Ion Impact" , ibid., 47, 1528 (1993).
A. Igarashi and N. Toshima: "Second-Order Born
Cross Sections for Positronium Formation in
Positron-Hydrogen Collisions" , ibid. , p. 2386.
K. Hino: "Double Photoionization of He by HighEnergy Photon Impact" , ibid. , p. 4845.
K. Hino, T. Ishihara, F. Shimizu, N. Toshima, andJ. H. McGuire: "Double Photoionization of Helium
Using Many-Body Perturbation Theory", ibid., 48,
1271 (1993).
T. Kambara, Y. Awaya, and Y. Kanai: "Multiple
Inner-Shell Ionization of Target Atoms by HighEnergy Heavy-Ion Impact", Radiat. Eff. Def. Solids,
126, 41 (1993).

Y. Zou, Y. Awaya, T. Kambara, Y. Kanai, M. Oura,
K. Ando, A. Hitachi, and S. Kravis: "Foil Target
Element and Incident Energy Dependence of Multiple Inner Shell Vacancy Production of Projectile Ar
Ions", ibid., p. 87.
H. Katsuragawa, M. Kubota, T. Minowa, and H.
Komatsu: "A Simple and Efficient Pulsed-Heating
Atomic Beam Source for Resonance Ionization Spectroscopy", Rev. Sci. Instrum., 64, 265 (1993).

K. Kimura and H. Kumagai: "Lifetime Shortening
and Quenching of Excitons of BaF 2 Single Crystal
Created by Heavy-Ion Induced High-Density Excitation", Rad. Eff. Def. Solids, 126, 45 (1993).
T. Kanai, T. Kohno, S. Minohara, M. Sudou, E.
Takada, F. Soga, K. Kawachi, and A. Fukumura:"Dosimetry and Measured Differential W Values ofAir for Heavy Ions", Radiat. Res., 135, 293 (1993).
5.

4.

Radiochemistry, radiation chemistry, and radiation biology

Y. Itoh and H. Murakami: "Defect Study on Electron
Irradiated GaAs by Means of Positron Annihilation" ,Appl. Phys., A57, 1 (1993).
Y. Itoh, H. Murakami, and A. Kinoshita: "Positron
Annihilation in Porous Silicon", Appl. Phys. Lett.,
63, 15 (1993).
T. Kanai, S. Minohara, T. Kohno, M. Sudou, E.
Takada, F. Soga, K. Kawachi, A. Fukumura, andF. Yatagai: "Irradiation of 135 MeV lu Carbon and
Neon Beams for Studies of Radiation Biology", HIMAC004 CNIRS-M-91, p. 1 (1993).
K. Kimura: "Depth and Time Resolved Dynamics for
Excited States in Ion Track", KEK Proc. 7th Rad.
Detect. Use, 93-8, p. 153 (1993).
K. Kimura: "Depth Resolved Dynamics of Ion-Tracks:
Correlation between VUV- and UV-Luminescencesfrom Near-liquid and Liquid Helium Irradiated with
4 MeV lamu N-ions", Nucl. Instrum. Methods Phys.
Res., A327, 34 (1993).
K. Nakagawa, K. Kimura, and A. Ejiri: "Photoionization Quantum Yield of TMAE (tetrakisdimethylaminoethylene) in Supercritical Xenon
Fluid", ibid., p. 60.
K. Kimura: "Track-Depth Resolved Dynamics of Helium Excimers in 4 MeV lamu N-ion Tracks in Nearliquid and Liquid Helium", Phys. Rev. A, 47, 327(1993).
Y. Ohkubo, Y. Kobayashi, K. Asai, T. Okada, and
F. Ambe: "Time-Differential Pert urbed- AngularCorrelation and Emission Mossbauer Studies on
99Ru Arising from 99Rh in Fe304", Phys. Rev. B,
47, 11954 (1993).
K. Kimura and J. Wada: "LET-dependent Competition between Radiative and Nonradiative Annihilations of Core Holes Produced by. Ion Irradiation of
BaF 2 Single Crystal", ibid., 48, 15535 (1993).
M. Matsushima, T. Kojima, K. Ogura, H. Yamada,T. Takahashi, T. Doke, and S. Nagaoka: "Determination of Cosmic HZE Particle' Trajectories Using
Image Analysis", Proc. 8th Symp. on Image Sensing
Technologies on Industry in Japan, p. 63 (1993).

Material analysis

J. Kawai, K. Nakajima, K. Maeda, and Y. Gohshi:"L X-Ray Line Shape of Copper(II) Compounds andTheir Covalency", Adv. in X-Ray Analysis, 35, 1107
(1992).
J. Kawai, K. Maeda, and T. Yamane: "Imaging Plate
X-Ray Spectrometer for High Resolution PIXE",
Anal. Sci., 9, 179 (1993).
S. Adachi , K. Takemoto, Y. Sasa, and K. Maeda:"PIXE Analysis of Hilar Gland for the Evaluationof Personal History of Exposure to Environmental
Contaminant", Int. J. PIXE, 2, 453 (1992).
T. Hanada, M. Mogi, J. Kawai, K. Maeda, Y. Sasa,
and M. Uda: "Nickel Lo: Spectra Measured by aHigh Resolution Particle Induced X-Ray Emission
Spectrometer", NUcl' Instrum. Methods Phys. Res.,
B75, 35 (1993).
K. Ishii, K. Maeda, M. Takami, Y. Sasa, M. Uda, and
S. Morita: "Continuous Background in Heavy-Ion
Induced X-ray Emission", ibid., p. 73.
Y. Nishide, E. Hayashi, K. Maeda, Y. Sasa, and M.
Uda: "PIXE Analysis of Calcified Tissue by Use of
a Combined X-Ray Absorber", ibid., p. 200.
K. Suzuki, K. Maeda, Y. Sasa, A. Okada, K. Sakamoto,and T. Ozawa: "Application of PIXE to Source Identification of Kosa Aerosol", ibid., p. 317.
M. Uda. T. Tsunokami, R. Murai, K. Maeda, 1.
Harigai , Y. Nakayama, S. Yoshimura, T. Kikuchi, K.
Sakurai, and Y. Sasa: "Quantitative Analysis of Ancient Egyptian Pigments by External PIXE", ibid.,
p.476.
K. Kakihara, S. Gohhara, T. Nishijima, S. Matsuo,
S. Itoh , and K. Maeda: "Metal Analysis by PIXE inthe Liver Tissure from Patients with Liver Diseases" ,ibid. , p. 52l.
K. Maeda, Y. Sasa, M. Takami, and M. Uda: "Determination of X-Ray Take-off Angle from the L/K
X-Ray Take-off Angle from the L/K X-Ray Intensity Ratio PIXE Analysis of a Nonflat Target", ibid.,
B77, 137 (1993).
K. Kanazawa, M. Yanokura, and M. Aratani, and H.
Akiyama: "Hydrogen Depth Profile of AI-alloy Vacuum Chamber Exposed to Synchrotron Radiation",
Vacuum, 44, 7 (1993).

175

VIII. LIST OF PREPRINTS1993
RIKEN-AF-NP
141 S. Hirenzaki, T. Suzuki, and I. Tanihata: "A General Formula of the Coalescence Model"
142 V. A. Chrchin and V. A. Tsarev: "On a Nonstationary Quantum Mechanical Origin of Cold Nuclear Fusion"
143 V. A. Tsarev: "Cold Fusion Researches in Russia"
144 V. A. Tsarev: "Lebedev Physical Institute Group Researches in the Field of Long-baseline Neutorinos"
145 S. Ohta: "Large Scale Numerical Simulation of the Three-state Potts Model"
146 T. Ichihara, Y. Fuchi, K. Hatanaka, M. Hosaka, S. Ishida, S. Kato, H. Kawashima, S. Kubono, S. Miyamoto,T. Niizeki, H. Ohnuma, H. Okamura, H. Orihara, N. Sakamoto, S. Takaku, Y. Tajima, M. H. Tanaka, H.
Toyokawa, T. Yamamoto, M. Yosoi, and M. Ishihara: "12 Ce 2 C, 12N) 12B Charge-exchange Reaction at
E/A = 135 MeV"
147 K. Tanaka, W. Bentz, and A. Arima: "EOS and Fermi-Liquid Properties in the liN Expansion of a
Relativistic Many-body Theory"
148 A. A. Korsheninnikov and T. Kobayashi: "Main Mechanisms in Fragmentation of the Exotic Nucleus 6He"
149 M. Oshima, T. Morikawa, H. Kusakari , N. Kobayashi, M. Sugawara, Y. H. Zhang, A. Ferragut, S. Ichikawa,N. Shinohara, Y. Nagame, M. Shibata, Y. Gono, and T. Inamura: "Double-gamma Vibrational States in
168Er and 1920s"
150 Y. Gono, T. Murakami, T. Morikawa, A. Ferragut , Y. H. Zhang, K. Morita, A. Yoshida, H. Kumagai, M.
Oshima, H. Kusakari, M. Sugawara, M. Ogawa, M. Nakajima, S. Mitarai, A. Odahara, E. Ideguchi, T.
Shizuma, M. Kidera, J. C. Kim, S. J. Chae, and B. J. Min: "High-Spin Isomers and High-Spin Isomer
Beams"
151 M. Mizoguchi, S. Hirenzaki, and H. Toki: "Microscopic Kaonic Atom Optical Potential in Finite Nuclei
with Lambda(1405) and Sigma(1385) Resonances"
152 D. Hirata: "Study of Unstable Nuclei with the Relativistic Mean Field Theory"
153 N. Fukunishi, T. Otsuka, and I. Tanihata: "Neutron-Skin and Proton-Skin Formations in Exotic Nuclei Far
From Stability"
154 S. Ohta: "Phases of the Three-state Potts Model in Three Spatial Dimensions"
155 A. A. Korsheninnikov, K. Yoshida, D. V. Aleksandrov, N. Aoi, Y. Doki, N. Inabe, M. Fujimaki, T. Kobayashi,
H. Kumagai, C. -B. Moon, E. Yu. Nikolskii, M. M. Obuti, A. A. Ogloblin, A. Ozawa, S. Shimoura, T. Suzuki ,I. Tanihata, Y. Watanabe, and M. Yanokura: "Observation of loHe"
156 A. A. Korsheninnikov, K. Yoshida, D. V. Aleksandrov, N. Aoi, Y. Doki, N. Inabe, M. Fujimaki, T. Kobayashi,
H. Kumagai, C. -B. Moon, E. Yu. Nikolskii, M. M. Obuti, A. A. Ogloblin, A. Ozawa, S. Shimoura, T. Suzuki,
I. Tanihata, Y. Watanabe, and M. Yanokura: "Experimental Study of the 8He + p Elastic and Inelastic
Scattering"
157 I. Tanihata: "Study of Light Exotic Nuclei Using Radioactive Nuclear Beams"
158 T. Kobayashi: "Projectile Fragmentation of Exotic Nuclear Beams"

176

A. A. Korsheninnikov, K. Yoshida, D. V. Aleksandrov, N. Aoi, Y. Doki, N. Inabe, M. Fujimaki, T. Kobayashi,
H. Kumagai, C. -B. Moon, E. Yu. Nikolskii, M. M. Obuti, A. A. Ogloblin, A. Ozawa, S. Shimoura, T. Suzuki,
I. Tanihata, Y. Watanabe, and M. Yanokura: "Experimental Study of Neutron Rich Helium Isotopes"
D. Hirata, H. Toki, I. Tanihata, K. Sumiyoshi, Y. Sugahara, and R. Brockmann: "Relativistic Mean Field
Theory for Unstable Nuclei"
A. Ozawa, T. Kobayashi, H. Sato, I. Tanihata, O. Yamakawa, K. Ornata, K. Sugimoto, N. Takahashi, T.
Shimoura, D. Olson, W. Christie, and H. Wieman: "Interaction Cross Sections and Radii of Mass Number
A = 17 Isobars (17N, 17p, and 17Ne)". T. Nakamura, T. Kobayashi, M. Fujimaki, N. Inabe, T. Kubo, T. Suzuki, I. Tanihata, Y. Watanabe, A.
Yoshida, T. Teranishi, N. Aoi, Y. Doki, M. Ishihara, S. Shimoura, N. Iwasa, K. Katori, and K. Abe:
"Coulomb Dissociation of 11 Be"
159 T. Ichihara, T. Niizeki, H. Okamura, H. Ohnuma, H. Sakai, Y. Fuchi, K. Hatanaka, M. Hosaka, S. Ishida, K.
Kato, S. Kato, H. Kawashima, S. Kubono, S. Miyamoto, H. Orihara, N. Sakamoto, S. Takaku, Y. Tajima, M.
H. Tanaka, H. Toyokawa, T. Uesaka, T. Yamamoto, T. Yamashita, M. Yosoi, and M. Ishihara: "Spin-Isospin
Resonances Observed in the (d, 2He) and (12C, 12N) Reactions at E/ A = 135 MeV"
160 K. Tanaka: "Quasiparticle Properties and the Dynamics of High-density Nuclear Matter"

177

IX. PAPERS PRESENTED AT MEETINGS
1.

Accelerator
physics

development

a ndaccelerator

M. Hara: "Photon Beam Characteristics from Insertion Device Sources of the SPring-8", JASRI Microbeam Formation Subcommittee 7th Study Meeting, Tokyo, Jan. (1992).
M. Hara: "Characteristics of Photon at SPring-B",
SPring-8 Workshop on Atomic Physics at High Brilliance Synchrotron Radiation Facilities, Himeji, Mar.
(1992).
M. Hara: "SPring-B, A Challenge to Highly Brilliant
Photon Source", Symp. on Charged Particle Optics,
Tsukuba, July (1992).
H. Ego, M. Hara, K. Inoue, Y. Kawashima, and Y.
Ohashi: "RF System of the Storage Ring for SPring8", 15th Int. Conf. on High Energy Accelerators,
Hamburg, Germany, July (1992).
H. Ego, M. Hara, K. Inoue, Y. Kawashima, and Y.
Ohashi: "High Power Test of the Storage Ring RF
System for SPring-B", ibid.
M. Hara: "SPring-8 Project", Seminar at Synchrotron
Trieste, Trieste, Italy, July (1992).
H. Ego, M. Hara, K. Inoue, Y. Kawashima, Y. Ohashi,
H. Suzuki, 1. Takeshita, and H. Yonehara: "HighPower Test of Single Cell Cavities for SPring-8" , 17th
Linear Accelerator Meet. in Japan, Sendai, Sept.
(1992).
H. Ego, M. Hara, K. Inoue, Y. Kawashima, Y. Ohashi,
H. Suzuki, and H. Yonehara: "On the Performancesof an Optical Fiber and Related Modules for the
Timing System of the SPring-B", Fall Meet. Phys.
Soc. Jpn., Niigata, Oct. (1992).
H. Ego, M. Hara, K. Inoue, K. Kawashima, Y. Ohashi,
H. Suzuki, 1. Takeshita, and H. Yonehara: "RF
System for the SPring-8 Storage Ring", APS Meet.
on RF System for RF Workshop, Argonne, U.S.A.,
Sept. (1992).
M. Hara: "RF System for the SPring-8 Storage Ring",
Int. Advisory Committee of the SPring-8, Himeji,
Nov. (1992).
H. Ego, M. Hara, K. Inoue, Y. Kawashima, Y. Ohashi,
H. Suzuki, I. Takeshita, and H. Yonehara: "Status of the SPring-8 RF System", 3rd Joint Symp.
on Synchrotron Radiation Sources, Pohang, Korea,
Nov. (1992).
M. Hara: "Light Source Performance of SPring-8",
JASRI 7th Subcommittee of Microbeam Formation,
Tokyo, Mar. (1993).
A. Goto: "RIKEN Cyclotron", 2nd Meet. on Biological Effect of High LET Particle Beams, Tokyo, Mar.
(1993).
H. Okamura, H. Sakai, N. Sakamoto, T. Uesaka, S.
Ishida, H. Otsu, T. Wakasa, K. Hatanaka, T. Kubo,
N. Inabe, K. Ikegami, J. Fujita, M. Kase, A. Goto,
and Y. Yano: "Development of the RIKEN Polarized
178

Ion Source" , Int. Workshop on Polarized Ion Sources
and Polarized Gas Targets, Madison, U.S.A., May(1993).
K. Watanabe, S. H. Be, Y. Oikawa, H. A. Sakaue,
C. Y. Xu, S. Yokouchi , Y. Wang, S. Takahashi, M.
Tsuchiya, and Y. Yanagi: "Vacuum Chamber andCrotch Absorber for the SPring-8 Storage Ring Vacuum System", Particle Accel. Conf., Washington,
D.C., U.S.A., May (1993).
H. Ego, M. Hara, Y. Kawashima, Y. Ohashi, T.
Ohshima, H. Suzuki, 1. Takeshita, and H. Yonehara:"Higher Order Modes of the Single Cell Cavity for
the SPring-8", 9th Symp. on Accelerator Sci. Tech.,
Tsukuba, Aug. (1993).
K. Kumagai and S. Matsui: "The Injection Septum Magnets of the SPring-8 Storage Ring" , 13th
Int. Conf. on Magnet Technology, British Columbia,
Canada, Sept. (1993).
H. Ego, M. Hara, Y. Kawashima, Y. Ohashi, H.
Suzuki, and H. Yonehara: "Phase Stabilized Fiber
Optic Links for the SPring-8 RF Reference Distribution", Fall Meet. Phys. Soc. Jpn., Kochi, Oct. (1993).
Y. Yano: "Present Status and Future Project of RARF
(RIKEN)", 5th China-Japan Joint Symp. on Accel.
for Nucl. Sci. and Their Applications, Osaka, Oct.
(1993).
A. Goto, Y. Miyazawa, O. Kamigaito, T. Nakagawa,
M. Hemmi, T. Chiba, M. Kase, N. Inabe, and Y.
Yano: "Upgrade Project of the RILAC", ibid.
K. Watanabe, K. Hayashi, T. Hanasaka, K. Yano, andS. H. Be: "Outgassing of Stainless Steel and Copper Due to Electron-Stimulated Desorption", Vacuum Conf., Tokyo, Oct. (1993) .
Y. Yano: "The Present Status and Future Plan of
RIKEN Accelerator Research Facility, Japan", 3rd
Natl. Seminar on Phys. and Technol. of Particle Accelerators and Their Applications, Calcutta, India,
Nov. (1993).
2.

Nuclear physics and nuclear instrumentation

S. Takagi, T. Nakamura, F. Makino, T. Kohno, and N.
Shiono: "Observation of Damage on IC Devices inthe Earth's Radiation Belt", 18th ISTS, Kagoshima,
May (1992).
K. Nagamine and P. W. Williams: "Muon Science Program in RIKEN-RAL Collaboration", Japan-U.K.
Seminar on Science and Technology, London, U.K.,
Oct. (1992).
K. Asahi: "Nuclear Moments Measured with Polarized
Projectile Fragments", RIKEN Symp. on Nuclear
Spectroscopy with Unstable Nuclear Beams, Wako,
Nov. (1992).
K. Yoshida, J. Kasagi, H. Hama, M. Sakurai, M.
Kodama, K. Furutaka, K. Ieki, W. Galster, T. Kubo,
M. Ishihara, and A. Galonsky: "Disappearance of

the Giant Dipole Resonance in Hot Nuclei Produced
in 40 Ar Induced Reaction", Japan-China Joint Nuclear Physics Symp. on Recent Topics on Nuclear
Physics, Tokyo, Nov./Dec. (1992).
H. Toki, D. Hirata, 1. Tanihata, K. Sumiyoshi, and
Y. Sugahara: "Relativistic Many Body Theory for
Unstable Nuclei", ibid.
S. Hirenzaki and H. Toki: "Structure and Formationof Deeply Bound Pionic Atoms", ibid.
K. Asahi, H. Okuno, H. Ueno, H. Sato, M. Adachi,
T. Kubo, T. Nakamura, N. Inabe, A. Yoshida, Y.
Ohkubo, T. Ichihara, M. Ishihara, T. Shimoda, H.
Miyatake, and N. Takahashi: "Spin Polarization byAbrasion Process in Intermediate-energy Heavy-ion
Collision and Its Application", ibid.
T. Matsuzaki and K. Ishida: "Present Status of Construction of RIKEN-RAL Muon Facility", RIKEN
Symp. on Muon Science 1992, Wako, Dec. (1992).
K. Tanaka: "Fermi-Liquid Properties of Nuclear Matter in a Relativistic Many-Body Theory", Workshop
on Relativistic Many-Body Methods for Bound Systems of Hadrons, Kyoto, Dec. (1992).
T. Ichihara: "RIKEN SMART Spectrograph: Overview, Detector and Recent Experiment" , S800 Workshop on Focal Plane Detectors, Michigan, U.S.A.,
Jan. (1993).
K. Nagamine: "Present and Future of Muon Catalyzed
Nuclear Fusion", Workshop on Nuclear Waste Transmutation Using Particle Beams, Tokai, Jan. (1993).
H. Sato: "Systematics of Isotope Production Rates:
Fission Products and Their Barrier Penetration",
2nd Meet. on Nuclear Incineration, Tokai, Jan.
(1993).
T. Matsuzaki: "Present Status of SLOW Facility",
RIKEN Symp. on Non Nucl. Phys. Res. by RRC,
Wako, Jan. (1993).
K. Nagamine: "Production and Application of LowEnergy Nuclear and Elementary Particle Beams",
ibid.
1. Tanihata:"Physics with Radioactive Nuclear
Beams", Brasilian Summer Seminar on Nuclear
Physics, Sao Paulo, Brasil, Jan./Feb. (1993).
T. Matsuzaki: "R & D in International Collaboration on Muon Facility at High-Intensity Proton
Accelerator-RIKEN-RAL", Workshop on Researchand Developments for JHP and Related Scientific
Topics, Tanashi, Mar. (1993).
K. Furutaka, J. Kasagi, T. Murakami, A. Yajima,
Y. Akeboshi, K. Matsuda, Y. Futami, K. YuasaNakagawa, T. Nakagawa, T. Murakami, S. Sawada,
Y. Nakai, T. Motobayashi, A. Galonsky, and G.
Bizard: "Measurements of Neutrons Emitted in
Heavy-Ion Fusion Reaction", RCNP Workshop on
Hot and Dense Nuclear Matter Produced in HeavyIon Reactions, RCNP, Osaka Univ., Osaka, Mar.
(1993).
K. Asahi, H. Okuno, H. Ueno, H. Sato, H. Izumi, T.
Sekine, M. Doi, M. Adachi, T. Kubo, T. Nakamura,

N. Inabe, A. Yoshida, Y. Ohkubo, M. Ishihara, T.
Shimoda, H. Miyatake, and N. Takahashi: "Spin Polarized Radioactive Nuclear Beam and Its Application", STA Forum for Multi-Disciplinary Researches,
Kobe, Mar. (1993).
1. Tanihata: "Usage of High Energy Radioactive Nuclear Beams", ibid.
A. A. Korsheninnikov: "Study of Nuclei beyond theDripline", ibid.
1. Tanihata: "Production and Use of Radioactive
Beams for Nuclear Structure and AstrophysicalStudies", JSPS-INS Spring School, Shimoda, Mar.
(1993).
H. Sato: "Systematics of Isotope Production Rates:
Mass Excess Dependence of Fission Products",
RIKEN Int. Workshop on Heavy-Ion Reactions with
Neutron-Rich Beams, Wako, Mar. (1993).
1. Tanihata: "Neutron Skins and Neutron Halos", 48th
Ann. Meet. of Phys. Soc. Jpn., Sendai, Mar./ Apr.
(1993).
S. Hirenzaki, T. Suzuki, and 1. Tanihata: "A General
Formula of the Coalescence Model", ibid.
S. Ohta: "Large-Scale Numerical Simulation of Thermodynamic Systems with Global Z(3) Symmetry",ibid.
K. Tanaka and W. Bentz: "Quasiparticle Properties
and the Dynamics of High-Density Matter in a Relativistic Many-Body Theory", ibid.
T. Murakami, Y. Gono, Y. H. Zhang, A. Ferragut, T.
Morikawa, E. Ideguchi, K. Morita, A. Yoshida, M.
Oshima, H. Kusakari, M. Sugawara, M. Ogawa, J. C.
Kim, S. J. Chae, B. J. Min, S. Mitarai, A. Odahara,
T. Shizuma, M. Kidera, and M. Shibata: "High Spin
Isomer Beams", ibid.
T. Uesaka: "The Development of Polarized DeuteronIon Source in RIKEN", ibid.
A. Yoshida, T. Fukuda, T. Sekine, Y. Watanabe, K.
Kimura, H. Okuno, H. Ueno, H. Izumi, Y. Mizoi,
M. Tanikawa, 1. Nomura, K. Asahi, M. Ishihara,
S. Shimoura, T. Nakamura, T. Kubo, and H. J.
Kim: "Subbarrier Fusion with Neutron-Rich Nuclear
Beams", ibid.
M. Tohyama: "Diffusion Coefficient for Nuclear Deformations", ibid.
K. Hasuike, H. Okada, T. Doke, J. Kikuchi, K.
Masuda, and M. Suzuki: "Energy Resolution of
TMA Doped Liquid Xe Pulsed Ionization Chamber" ,ibid.
M. Suzuki, T. Takahashi, H. Kumagai, K. Agata, N.
Takahashi, S. Kamiya, S. Hirasawa, S. Sugawara,and H. Kobayashi: "On the Development of a Single
Neutron Sensitive Camera", ibid.
M. Wakasugi, W. G. Jin, T. T. Inamura, T. Murayama,
T. Wakui, T. Kashiwabara, H. Katsuragawa, T.
Ariga, T. Ishizuka, M. Koizumi, and 1. Sugai:"Quadrupole Moment of 180Ta", ibid.
K. Nagamine: "Construction of RIKEN-RAL Muon
Facility", Workshop on Low Energy Muon Science,
179Santa Fe, U.S.A., Apr. (1993).
1. Tanihata: "Study of Nuclei Far from the Stability
Using Radioactive Nuclear Beams", Flerov Laboratory School-Seminar, Dubna, Russia, May (1993).
A. Ozawa, T. Kobayashi, H. Sato, 1. Tanihata, O.
Yamakawa, K. Ornata, K. Sugimoto, N. Takahashi,
T. Shimoda, D. Olson, W. Christie, and H. Wieman:"Interaction Cross Sections and Radii of Mass Number A=17 Isobars 7 N, 17F, and 17Ne)", 3rd Int.
Conf. on Radioactive Nuclear Beams, Michigan,
U.S.A., May (1993).
A. A. Korsheninnikov, K. Yoshida, D. V. Aleksandrov,
N. Aoi, Y. Doki, N. Inabe, M. Fujimaki, T.
Kobayashi, H. Kumagai, C.-B. Moon, E. Yu.
Nikolskii, M. M. Obuti, A. A. Ogloblin, A. Ozawa,S. Shimoura, T. Suzuki, I. Tanihata, Y. Watanabe,
and M. Yanokura: "Experimental Study of Neutron
Rich Helium Isotopes", ibid.
D. Hirata, H. Toki, 1. Tanihata, K. Sumiyoshi, Y.
Sugahara, and R. Brockmann: "Relativistic Mean
Field Theory for Unstable Nuclei", ibid.
K. Matsuta, A. Ozawa, Y. Nojiri, T. Minamisono, M.
Fukuda, S. Momota, T. Ohtsubo, S. Fukuda, K.
Sugimoto, 1. Tanihata, K. Yoshida, K. Ornata, J. R.
Alonso, G. F. Krebs, and T. J. M. Symons: "Production and Polarization of Beta-emitting 43Ti", ibid.
T. Nakamura, S. Shimoura, T. Kobayashi, T.
Teranishi, H. Okuno, Y. Watanabe, A. Yoshida, N.
Inabe, T. Suzuki, M. Fujimaki, K. Abe, N. Iwasa,
T. Kubo, K. Katori, 1. Tanihata, and M. Ishihara:"Coulomb Dissociation of 11 Be", ibid.
H. Toki: "Pion Absorption and the Properties of Delta
in Nuclei", Int. Symp. on Delta Excitation in Nuclei
at RIKEN, Tokyo, May (1993).
K. Nagamine: "RIKEN-RAL Muon Facility and Advanced ILSR Research", Int. Conf. on Muon Spin Rotation, Maui , U.S.A. , June (1993).
T. Kohno: "Observation of Large Proton Intensity
Gradient at Geosynchronous Orbit on October 2731, 1991 According to GMS-4 and GOES-7 Measurements" , Int. Workshop on Space Radiation Environment: Empirical and Physical Models, Dubna, Russia, June (1993).
S. Hirenzaki and H. Toki: "Formation of Deeply
Bound Pionic Atoms by (d, 3He) Reactions", Particle and Nuclei XIII Int. Conf. (PANIC), Perugia,
Italy, June/July (1993).
1. Tanihata: "Future Use of Radioactive Nuclear
Beams" , Gordon Conf. on Nuclear Chemistry, New
Hampsure, U.S.A., July (1993).
T. Kohno and A. Struminsky: "Peculiarities of Solar
Proton Spectrum in Stratosphere and Geostationary
Orbit on 2- 3 November 1992", 23rd Int. Cosmic Ray
Conf., Calgary, Canada, July (1993).
K. Nagamine: "Science Research with Pulsed Muonsthe First 12 Years and Next Futur~", PSI Colloquim, Zurich, Swiss, Aug. (1993).

e180

T. Ichihara: "Spin-isospin Resonances Observed inthe (d, 2He) and 2 C, 12N) Reactions at E/A =135 MeV", Gull Lake Nuclear Physics Conf. on Giant Resonances, Gull Lake, Michigan, U.S.A. , Aug.
(1993).
K. Nagamine: "Recent Muon Science Research inJapan", Heidelberg University Physics Colloquim,
Heidelberg, Germany, Sept. (1993) .
M. Suzuki, T. Takahashi, Y. Awaya, M. Oura, and T.
Mizogawa: "A Gas Scintillation Proportional X-ray
Imaging Chamber", 3rd London Conf. on PositionSensitive Detectors, BruneI, U.K., Sept. (1993).
K. Nagamine: "Towards Ultra-High Fusion Density
Muon Catalyzed Fusion", ICENES '93, Makuhari,
Sept. (1993).
K. Nagamine: "Advanced Muon Catalyzed Fusion Research Program at RIKEN-RAL Facility" , ibid.
K. Nagamine: "Overview of Muon Catalyzed Fusion Experiment", RIKEN Symp. on Muon Sci.
1993 (Muon Catalyzed Nuclear Fusion), Wako, Sept.
(1993) .
K. Nagamine: "Plans for ILCF Experiment at RIKENRAL Muon Facility", ibid.
K. Nagamine: "Slow Muon Source Using ILCF", ibid.
T. Motobayashi: "Comments on the Coulomb Dissociation", Workshop on Selected Topics in Nuclear
Astrophysics, Tokyo, Sept. (1993).
I. Tanihata:"Physics with Radioactive Nuclear
Beams", Int. School of Heavy Ion Physics, 3rd
Course: Probing the Nuclear Paradigm, Erice-Sicily,
Italy, Oct. (1993).
I. Tanihata: "How Well Did We Understand theDripline?", 9th High-Energy Heavy-Ion Study,
Berkeley Ca. , U.S.A. , Oct. (1993).
T. Motobayashi: "Multi-step Excitation Effects in the
14 0 Coulomb Dissociation"; "Preliminary Results of
the 8B Coulomb Dissociation Related to the Reaction 7Be(p,, )8B Producing Solar Neutrinos" ; "Nuclear Breakup Contribution in the 16 0 - t 12 C + a
Dissociation", Workshop on Coulomb Dissociationof Light Nuclei, Strasbourg, France, Oct. (1993).
T. Nakamura: "Coulomb Dissociation of a Halo N ucleus", ibid.
S. Ohta: "First-Order Phase Transition with Global
Z(3) and Z(4) Symmetry", 1993 Int. Symp. on Lattice Field Theory 'Lattice 93 ', Dallas, U.S.A., Oct.
(1993).
T. Motobayashi: "Determination of Astrophysical
Reaction Rates through the Coulomb Dissociation
Method", 1993 Fall Meet . Phys. Soc. Jpn. , Kochi ,Sept./Oct. (1993).
N. Fukunishi: "Excitation of 9Li Core in 11 Li", ibid. ,Kochi, Oct. (1993).
K. Yoshida, 1. Tanihata, T. Kobayashi, T. Suzuki, S.
Shimoura, K. Sugimoto, K. Matsuta, S. Fukuda, H.
Wieman, W. Christie, and D. Olson: "Coincidence
Measurements for Neutrons and a Particles from theeFragmentation of 6He at 800 A MeV", ibid.
Y. Futami, S. Tomita, Y. Honjo, T. Mizota, H.
Toyokawa, K. Matsuda, K. Furut aka , K. YuasaNakagawa, J. Kasagi, T. Nakagawa, S. M. Lee, andW. Q. Shen: "Correlation between Fission Fragments and Light Particles in the Reactions 84 Kr +27 AI, 56Fe (EL = 10.5 MeV lu)" , ibid.
A. Odahara, Y. Gono, S. Mitarai, H. Tomura, E.
Ideguchi, T. Shizuma, M. Kidera, M. Shibata, T.
Morikawa, T. Kishida, Y. H. Zhang, A. Ferragut, K.
Morita, A. Yoshida, T. Murakami, M. Oshima, H.
Kusakari, M. Sugawara, B. J. Min, C. J. Kim, andS. J. Chae: "High Spin Isomer and Level Structureof 145S m", ibid.
T. Morikawa, T. Kishida, Y. H. Zhang, A. Ferragut,
K. Morita, A. Yoshida, Y. Gono, S. Mitarai, A.
Odahara, E. Ideguchi, T. Shizuma, M. Kidera, M.
Shibata, T. Murakami, M. Oshima, H. Kusakari, M.
Sugawara, B. J. Min, C. J. Kim, S. J. Chae, and S.
A. Shin: "High Spin Isomer Beams", ibid.
E. Ideguchi, Y. Gono, T . Morikawa, and T. Kishida:"Simulation of a ,-ray Spectrum for a Segmented Ge
Detector" , ibid.
T. Ariga, M. Wakasugi, W. G. Jin, T. T. Inamura, T.
Murayama, T. Wakui, H. Katsuragawa, T. Ishizuka,
M. Koizumi, and I. Sugai: "Precise Measurement ofHyperfine Structure in 183W with Laser-rf Double
Resonance", ibid.
M. Suzuki, T. Takahashi, T. Mizogawa, M. Oura, andY. Awaya: "On the Development of a Proportional
Scintillation X-ray Imaging System", ibid.
A. Ozawa, I. Tanihata, T. Kobayashi, O. Yamakawa,
K. Ornata, H. Sato, D. Hirata, N. Takahashi, T.
Shimoda, K. Sugimoto, D. Olson, W. Christie, and
H. Wieman: "Interaction Cross Sections and Radii ofMass Number A = 17 Isobars (l7N, 17F, and l7Ne)",ibid.
N. Iwasa, T. Motobayashi, S. Shimoura, M. Gai,
T. Delbar, Y. Watanabe, T. Kubo, N. Inabe, Y.
Futami , K. Furut aka , M. Kurokawa, H. Murakami,
Y. Ando, T. Teranishi, K. Harn, Z. Zhao, R. France,
S. Shirato, J . Ruan, and M. Ishihara: "Measurementof the Reaction Cross Section of 7Be(p,,)8B with 8B
Coulomb Dissociation Method" , ibid.
T. Ichihara, T. Niizeki , H. Ohnuma, S. Ishida,
T. Uesaka, H. Ogami, H. Okamura, H. Orihara,
K. Kato, S. Kubono, M. Tanaka, Y. Fuchi, T.
Yamamoto, T. Yamashita, and M. Ishihara: "SpinIsospin Resonances Observed in the (l2C , 12N) Reactions at EI A = 135 MeV", ibid.
T. Uesaka, H. Sakai, H. Okamura, S. Ishida, N.
Sakamoto, H. Ohtsu, T. Wakasa, T. Ichihara, Y.
Yano, K. Hatanaka, H. Ohnuma, T. Niizeki, andT. Yamamoto: "Analyzing Power Measurements for
Deuteron Elastic Scatering (Ed = 270 MeV)", ibid.
T. Niizeki: "Spin-Isospin Excitation in Light Nuclei" ,ibid.
K. Matsuzaki: "Activation of Inorganic Scintillator
YAP, GSO, and NAI", ibid.
M. Tohyama: "Giant Resonances in a Neutron Rich
Nucleus", ibid.
H. Izumi, K. Asahi, H. Okuno, H. Ueno, K. Nagata,
Y. Hori, M. Adachi, A. Yoshida, G. Liu, N. Nori, T.
Sekine, H. Sato, M. Doi, M. Harada, and M. Ishihara:"Measurement of Electric Quadrupole Moments for
Neutron-rich Nuclei 14B and 15B", ibid.
H. Kitagawa, Y. Nishino, S. Tadokoro, and T. Suzuki:"Distribution of Perturbative Gluon in the MIT Bag
Model", ibid.
H. Kitagawa, A. Ozawa, and 1. Tanihata: "Reaction
Cross Sections of Light Mirror Nuclei (A = 17) in
the Glauber Model", ibid.
K. Furut aka , J. Kasagi, T. Murakami, A. Yajima,
Y. Akeboshi, K. Matsuda, Y. Futami, K. YuasaNakagawa, T. Nakagawa, T. Murakami, S. Sawada,
Y. Nakai, T. Motobayashi, A. Galonsky, and G.
Bizard: "Measurements of Neutrons Emitted in
40 Ar + 116Sn Reactions at EI A ~ 30, 37 MeV lu",
ibid.
K. Tanaka: "Quasiparticle Properties and the Dynamics of High-Density Matter in a Relativistic ManyBody Theory II", ibid.
T. Nakamura, T. Teranishi, N. Aoi, Y. Doki, M.
Ishihara, T. Kobayashi, M. Fujimaki, N. Inabe, T.
Kubo, T. Suzuki, 1. Tanihata, Y. Watanabe, A.
Yoshida, S. Shimoura, N. Iwasa, K. Katori, and K.
Abe: "Coulomb Dissociation of 11 Be" , ibid.
S. Hireilzaki, N. Fukunishi, D. Hirata, and H.
Kitagawa: "eHe, t) Reactions on Unstable Nuclei",ibid.
H. Suganuma, H. Monden, S. Sasaki, and H. Toki: "Influence of the Abelian Monopole Condensation on
the Chiral Condensate", ibid.
T. Horihata and N. Onishi: "Wobbling Motion by theConstrained HFB" , ibid.
J. Chiba, D. Ashery, H. Ito, K. Kimura, Yu. T. Kiselev,
S. Kouda, K. Miyano, T. Murakami, T. Nagae, Y.
Nakai, M. Nomachi, S. Sawada, M. Sekimoto, Y.
Sugaya, T. Suzuki, K. H. Tanaka, M. K. Vlasov, andY. Yoshimura: "Subthreshold Antiproton Production in pA and dA Collisions III" , ibid.
Y. Yoshimura, D. Ashery, H. Ito, J. Chiba, K. Kimura,Yu. T. Kiselev, S. Kouda, K. Miyano, T. Murakami,
T. Nagae, Y. Nakai, M. Nomachi , S. Sawada, M.
Sekimoto, Y. Sugaya, T. Suzuki, K. H. Tanaka, and
M. K. Vlasov: "Subthreshold Antiproton Production
in pA and dA Collisions IV" , ibid.
H. Sato: "Systematics of Alpha Q-values: Potential
Dependence of the Alpha Decay Life Time", Symp.
on Science of Beams of Short Life Nuclei '93, Tokyo,
Dec. (1993).

181

3.

Atomic and solid-state physics

H. Katsuragawa, T. Minowa, M. Kubota, and H.
Komatsu: "Resonance Ionization Spectroscopy of a
Mo Atomic Beam Generated by a Laser Ablation" ,Fall Meet. Opt. Soc. Jpn. , Kyoto, Nov. (1992).
K. Asahi: "Polarization Using the Projectile Fragmentation Reaction and Its Application to Solid State
Physics" , INS Symp. on Science with Short-lived Nuclear Beams, Tanashi , Jan. (1993) .
A. Hitachi, J. A. LaVerne, and J. L. Kolata: "High
Resolution Measurements of Heavy Ions by Alleneadded Liquid Argon Ionization Chamber" , Radiation
Detection and Its Application, Tsukuba, Jan. (1993).
Y. Matsuo, H. Maeda, and M. Takami: "Ion-moleculeInteraction and Spectroscopy in an rf Ion Trap",
RIKEN Symp. on Laser Science (15t h), Wako , Feb.
(1993) .
T. Kambara: "New Beams and Atomic Physics", STA
Forum for Multi-Disciplinary Researches- Exploring
New Researches with Radioactive Nuclear Beams
and Muon Beams, Kobe , Mar. (1993).
Y. Awaya: "Summary Reports of Atomic Physics Session", ibid.
R. Kadono: "A Prospect of J.LSR in Condensed Matter
Physics", ibid.
M. Sataka, M. Imai , Y. Yamazaki , K. Komaki , K.
Kawatsura, Y. Kanai , and H. Tawara : "Ion Charge
Dependence of Binary Encounter Electrons Peak",
48th Ann. Meet. Phys. Soc. Jpn ., Sendai, Mar.
(1993).
E. Vagi: "Introductory Talk to the Symposium on the
Application of Nuclear Methods to the Studies ofDefects and Impurities in Solids" , ibid.
T. Okada, K. Asai , N. Yamada, T. Matsumoto, Y.
Yamada, and Y. Kodama: "Mossbauer Study ofYBa2(Cul-xFex)40S II", ibid.
R. Kadono, A. Matsushita, K. Nishiyama, and K.
Nagamine: "Muon-induced Excition Luminescencein RbBr", ibid.
R. Kadono: "Anomalous Muonium State and Radiolysis", ibid.
Y. Matsuo, M. Wakasugi, H. Maeda, and M. Takami:"RF Ion Trap of Surface Implanted Elements Using
Laser Ablation Method" , ibid.
R. Kadono: "A Prospect of J.LSR in Condensed Matter
Physics" , ibid.
H. Qui, E. Yagi, and M. Hashimoto: "Effect of BiasVoltage on Structure and Resistivity of Ni Films
Prepared by DC Sputter-Deposition Method" , 40th
Ann. Meet. Jpn. Soc. Appl. Phys., Tokyo, Mar.
(1993).
H. Qui, A. Kosuge, H. Nakai, S. Yugo, M. Hashimoto,G. Safran, B. Pecz, P. B. Barna, E. Vagi , and H.
Maruyama: "Effect of Bias-Voltage on Structuraland Physical Properties of Ni Films DC-SputterDeposited on Si(100) and Si0 2" , 2nd Int. Symp.

182

on Sputtering and Plasma Processes, Tokyo, May(1993).
R. Kadono, A. Matsushita, K. Nishiyama, and K.
Nagamine: "Muon Radiolysis in Alkali Halides", Int.
Conf. Muon Spin Rotation/Relaxation/Resonance,
Maui, Hawaii, June (1993).
R. Kadono, S. Fujii, A. Matsushita, K. Nagamine, K.
Nishiyama, and S. Tanigawa: "Quantum Diffusion of
Muonium in GaAs with Shallow Donor Impurities" ,ibid.
R. Kadono, J. H. Brewer, K. Chow, S. R. Kreitzman,
Ch. Niedermayer, T . M. Riseman, J. W. Schneider,and T. Yamazaki: "Critical Behavior of Electric
Field Gradient in MnSi Probed by Muon LevelCrossing Resonance" , ibid.
R. Kadono: "Muon Diffusion in Crystalline Solids" ,ibid.
Y. Kanai: "Status of Atomic Physics Research in Foreign Countries" , RIKEN Symp. on Atomic Physics
with Accelerators XII, Wako , June (1993).
H. Tawara, T. Tonuma, H. Kumagai, and T. Matsuo:"Multiply Charged Secondary Ions from Condensed
Molecular Gas Targets under Highly Ionized Heavy
Projectile Impact-Molecular Structure Effect", 18th
Int. Conf. on Phys. of Electronic and Atomic Collisions, Aarhus, Denmark, July (1993).
T. Tonuma, H. Kumagai , T . Matsuo, H. Shibata,and H. Tawara: "Positively and Negatively Charged
Clusters Produced from Frozen Oxygen, Nitrogenand Carbon Monoxide Molecules under Energetic
Heavy Ion Impact", ibid.
H. Takagi, S. Hara, and H. Sato: "Off-the-energy-shell
Effects in Dissociative Recombination of Ht + e, H" ,ibid.
M. R. Harston, S. Hara, M. Kamimura, and I.
Shimamura:"Corr~ctions on Resonance Energies of Muonic Molecules [(d+J.L) + -d+ Je- e- and[(ddJ.L)+ -d+]e-e-" , ibid.
E. G. Armour, C. P. Franklin, D. M. Lewis, and
S. Hara: "Auger De-excitation within the Muonic
Molecule, [( dtJ.L )deeJ " , ibid.
T. Kambara, Y. Kanai , S. Kravis, Y. Nakai , M. Oura,and Y. Awaya: "Scattering Angle Dependent Measurements of Charge States of Projectile and Recoil
Ions in 47 MeV Ar-Ar Collisions" , ibid.
J. Z. Tang, S. Watanabe, and M. Matsuzawa: "VeryNarrow Doubly Excited States of He by HSCC andM QDT Methods", ibid.
M. Oura, T. Kambara, Y. Kanai, S. Kravis, Y. Nakai,
Y. Awaya, and B. D. DePaola: "Measurement ofRadiative Electron Rearrangement X-rays from Projectile Ions Excited by a Carbon Foil" , ibid.
H. Tawara, T. Tonuma, H. Kumagai , and T. Matsuo:"Secondary Ions Produced from Condensed Rare
Gas Targets under Energetic Ion Impacts", 5thWorkshop on Fast Ion-Atom Collisions, Debrecen,
Hungary, July (1993).

Y. Awaya: "JAERI-RIKEN 8 GeV Synchrotron Radiation Facility- SPring-8", ibid.
M. Oura, Y. Awaya, T. Koizumi, Y. Itoh, S. Kravis,
T. M. Kojima, M. Sano, M. Kimura, and K. Okuno:"Research and Development for Photoionization ofMultiply Charged Ions at SPring-8", ibid.
T. Kambara: "Target Multiple Ionization in Hard andSoft Ion Atom Collisions", 18th Int. Seminar on IonAtom Collisions, Stockholm, Sweden, July (1993).
J. Z. Tang: "Doubly Excited States in the Photodetachment Spectra of H-", 4th UK-Japan Seminaron the Theory of Atomic Collisions, Belfast, U.K.,
July (1993) .
Y. Matsuo, M. Wakasugi, H. Maeda, and M. Takami:"Laser Spectroscopy of Trace Atoms in an Rf Ion
Trap: Storage of Ions Produced by Laser Ablationof Implanted Atoms", Int. Symp. on Atomic Frequency Standards and Coherent Quantum Electronics, Nara, Aug. (1993).
M. Terasawa, T. Mitamura, T. Kohara, K. Ueda, H.
Tsubakino, A. Yamamoto, Y. Awaya, T. Kambara,
Y. Kanai, M. Oura, and Y. Nakai: "High Energy
Heavy Ion Irradiation Effects on Electron Transport
Property in La2-xSrxCu04", 3rd IUMRS Int. Conf.
on Advanced Materials, Tokyo, Aug. (1993).
S. Kravis, M. Oura, Y. Awaya, and K. Okuno: "An
EBIS for Use with Synchrotron Radiation", 5th Int.
Conf. on Ion. Sources, Beijing, China, Aug. (1993).
Y. Kanai: "Experiments by Low-velocity Highly
Charged Ions", 18th Meet. Soc. for Atomic Collision,
Koganei , Aug. (1993).
M. Suzuki, T. Takahashi, Y. Awaya, M. Oura, andT. Mizogawa: "A Proportional Scintillation X-ray
Imaging Chamber and Its Performance", 3rd London Conf. on Positron-Sensitive Detectors, London,
U.K., Sept. (1993).
H. Qui, H. Nakai, M. Hashimoto , H. Maruyama, E.
Yagi, G. Safran, M. Adamik, and P. B. Barnas: "Effect of Bias-Voltage on Epitaxial Growth and Physical Properties of Ni Films DC-Sputter-Deposited on
MgO(100)", 1993 Fall Meet. Jpn. Soc. Appl. Phys.
Related Soc. , Sapporo, Sept. (1993).
M. Hacke and E. Yagi: "Annealing Behaviour of KrImplanted Aluminium", 8th Int. Conf. on Surface
Modification of Metals by Ion Beams, Kanazawa,
Sept. (1993).
S. Sakamoto and K. Ishida: "Muon Transfer Experiment" , RIKEN Symp. on Muon Science, Wako, Sept.
(1993).
M. Kimura, N. Shimakura, N. F. Lane, S. Kravis , I.
Shimamura, Y. Awaya, and K. Okuno: "Single- andDouble Electron Capture in Collisions of Multiply
Charged Ions, He 2+, cq+(q = 4, 5), and Arq+(q = 6,
8) Ions with H2 Molecules at eV Collision Energies",
46th Gaseous Electronics Conf., Montreal, Canada,
Oct. (1993).
R. Kadono: "Dynamics of Hydrogenic Impurity (Muonium) in GaAs" , 3rd Lattice Defect Forum on Fron-tier of Physics on Defects, Kurashiki, Oct. (1993).
R. Kadono, A. Matsushita, K. Nishiyama, K.
Nagamine, S. Fujii, and S. Tanigawa: "Quantum
Diffusion of Muonium in GaAs: Effect of Shallow
Donor Impurities", 1993 Fall Meet. Phys. Soc. Jpn.,
Okayama, Oct. (1993).
E. Yagi and M. Hacke: "Annealing Behaviour of KrImplanted Aluminium", ibid.
T . Okada, K. Asai, N. Yamada, T. Matsumoto, Y.
Yamada, and Y. Kodama: "Mossbauer Study of Oriented 124 Compound", ibid.
S. Hashimoto, T. Minowa, H. Komatsu, and H.
Katsuragawa: "Resonance Ionization Spectroscopy
of Fe", ibid.
Y. Matsuo and M. Takami: "Lifetimes of Lu+ Excitedand Meta-stable States in an rf Ion Trap", ibid.
M. Terasawa, T. Mitamura, T. Kohara, K. Ueda, H.
Tsubakino, A. Yamamoto, Y. Awaya, T. Kambara,
Y. Kanai , M. Oura, and Y. Nakai: "High Energy
Heavy Ion Irradiation Effects on Electron Transport
Property in La1.8SSrO.lSCu04" , ibid.
Y. Yamazaki , K. Komaki, T. Azuma, K. Kuroki, Y.
Kakutani, K. Kawatsura, T. Kambara, Y. Kanai,
M. Oura, Y. Nakai, and Y. Awaya: "Inverse Mott
Scattering of Conduction Electrons in Ferromagnets
by Fast Heavy Ions" , ibid.
M. Sataka, M. Imai, Y. Yamazaki, K. Komaki, K.
Kawatsura, Y. Kanai, H. Tawara, and D. R. Shultz:"Binary Peak Electrons at 0° for Multiple Charged
Gold Ion in Collisions with He-atom", ibid.
Y. Kanai, T. Kambara, M. Oura, S. Kravis, Y. Awaya,
and Y. Zou: "Ion Charge Dependence of Peak Energy for Binary Encounter Electrons", ibid.
T. Kambara, Y. Kanai, S. Kravis, Y. Nakai, M. Oura,and Y. Awaya: "Multiple Ionization of Target Ar
Atom by 42 MeV Ar-Ion Collision", ibid.
M. Oura, T. Kambara, Y. Kanai , S. Kravis, Y. Nakai,
Y. Awaya, and B. D. DePaola: "Study of Radiative
Electron Rearrangement X-rays from Ti Ions", ibid.
M. Oura, S. Kravis, Y. Awaya, K. Okuno, and M.
Kimura: "R&D of EBIS for Experiments Using Synchrotron Radiation", ibid.
T. Koizumi , T. Itoh, M. Oura, S. Kravis, M. Sano, M.
Sekioka, T. Yamashita, and Y. Awaya: "Photoionization with 4d Electron Excitation of Ba+", ibid.
K. Nagamine, K. Nishiyama, and R. Kadono: "Solid
State Physics and Wide Applications Using Muons",
RIKEN Symp. on Researches on Solid State Physics
and Materials, Atomic Physics , Nuclear Chemistry,
Biology and Medicine Using RIKEN Ring Cyclotron
VII, Wako, Oct. (1993).
T. Kambara: "Future Possibilities in Atomic Physics
with Heavy Ions", ibid.
M. Suzuki, T. Takahashi, Y. Awaya, M. Oura, T.
Mizogawa: "On the Development of a Proportional
Scintillation X-ray Imaging Chamber", Int. Workshop on Area Detectors, Harima Science Garden
City, Hyogo, Nov. (1993).
183

M. Terasawa, T. Mitamura, T. Kohara, K. Ueda, H.
Tsubakino, A. Yamamoto, Y. Awaya, T. Kambara,
Y. Kanai, M. Oura, and Y. Nakai: "GeV Energy
Heavy Ion Irradiation on Oxide Superconductor",
Workshop for High Temperature Superconductivity,
Tokai, Dec. (1993).
J. Z. Tang: "Spectra of Highly Excited States ofHe", Workshop for Quantum Chaos, Highly Excited
Atom, and Highly Excited Molecule, Nagoya, Dec.
(1993).
E. Yagi: "Research Activities by Using a Small Tandem Accelerator in RIKEN", Symp. N ucl. ResearchLab. Fac. Eng., Univ. Tokyo, Tokyo, Dec. (1993).
E. Yagi: "Behaviour of Kr Atoms in Aluminium", IMR
Tohoku Univ. Symp. on Behaviour of Hydrogen andHelium in Metals under Particle Irradiation, Sendai,
Dec. (1993).
4.

Radiochemistry, radiation chemistry, and radiation biology

A. Yokoyama, K. Takesako, T. Saito, H. Kusawake, H.
Baba, Y. Ohkubo, A. Shinohara, and M. FUrukawa:"Limiting Behavior in the Medium Energy HeavyIon Nuclear Reactions", Specialists' Meet. on Scienceand Engineering of Fission, Kumatori, Dec. (1992).
F. Yatagai: "Analysis of Biological Damages Induced
by Heavy Ions", RIKEN Symp. on Researches on
Solid State Physics and Materials, Atomic Physics,
Nuclear Chemistry, and Biology and Medicine Using
RIKEN Ring Cyclotron, Wako, Jan. (1993).
K. Kimura: "Depth and Time Resolved Dynamics for
Excited States in Ion Track", Symp. on Radiation
Detectors and Their Uses, Tsukuba, Jan. (1993).
S. Ambe, Y. Ohkubo, Y. Kobayashi, M. Iwamoto, M.
Yanokura, H. Maeda, and F. Ambe: "Transport ofTc and Re through a Supported Liql:lid-Membrane",
Topical Symp. on the Behavior and Utilization ofTechnetium '93, Sendai, Mar. (1993).
K. Kimura: "Depth and Time Resolved Dynamics
of Ion Tracks by Means of Luminescence Measurements", 48th Ann. Meet. Phys. Soc. Jpn., Sendai,
Mar. (1993).
S. Ambe, Y. Ohkubo, Y. Kobayashi, M. Iwamoto, H.
Maeda, M. Yanokura, and F. Ambe: "Study on Distribution of Radioactive Nuclides in Plants", 1993
Ann. Meet. Atomic Energy Soc., Kyoto, Mar. (1993).
Y. Minai, Y. Takahashi, M. K. Kubo, S. Toyoda, M'.
Ishibashi, H. Ohtsuka, S. Ambe, Y. Kobayashi, Y.
Ohkubo, M. Iwamoto, M. Yanokura, H. Maeda, S.
Shibata, N. Takematsu, F. Ambe, and T. Tominaga:"Multitracer Study on Dependence of HumateComplex Stability on Ionic Radii and Charge ofMetal Ion", 65th Natl. Meet. Chern. Soc. Jpn.,(Spring), Tokyo, Mar. (1993).
Y. Kobayashi, S. Ambe, Y. Ohkubo, M. Iwamoto, H.
Maeda, M. Yanokura, and F. Ambe: "Preparation of184

a Multitracer from Gold Foils Irradiated with Heavy
Ions by Solvent Extraction", ibid.
K. Takesako, S. Watanabe, M. Kiriu, T. Saito, H.
Kusawake, A. Yokoyama, H. Baba, Y. Ohkubo, A.
Shinohara, E. Taniguchi, and M. FUrukawa: "Studyon Low- and Intermediate-Energy Heavy-Ion Induced Nuclear Reactions by Radiochemical Methods", ibid.
M. Watanabe, M. Suzuki, K. Suzuki, K. Nakano, F.
Yatagai, and T. Kanai: "LET Dependency of Mutation Induction at the HGPRT Locus and Molecular
Characterization of Mutations in Human Cells Irradiated with Accelerated Carbon Ions", Int. Seminaron Molecular Mechanisms in Radiation Mutagenesis and Carcinogenesis, Doorwerth, The Netherlands,
Apr. (1993).
Y. Itoh, H. Murakami, and A. Kinoshita: "Characterization of Porous Silicon by Positron Annihilation" , 4th Int. Workshop on Positron and Positronium Chemistry, Strasburg, France, June (1993).
K. Ando, S. Koike, S. Furukawa, M. Kimoto, M. Iizuka,
T. Kiuchi, W. Shimizu, T. Sugita, C. C. Koo, T.
Kanai, S. Matsushita, and F. Yatagai: "Saturation of Skin Damage after Accelerated Carbon Particles", Int. Congr. of Radiation Oncology, Kyoto,
June (1993).
K. Kimura: "LET-dependent Competition between
Radiative and Nonradiative Annihilations of Core
Holes Produced by Ion Irradiation of BaF 2 , Single
Crystal" , 15th Int. Conf. Atom. Phys. Sol., London,
Canada, July (1993).
F. Ambe: "Usefulness of Multitracers" , 30th Ann.
Meet. Radioisot. Phys. Sci. Ind. , Tokyo, July (1993).
M. FUrukawa, A. Shinohara, E. Taniguchi, J. Kurachi,
S. Kojima, T. Saito, Y. Ohkubo, and F. Ambe: "Production of Multitracer Nucleids by IntermediateEnergy Heavy-Ion Nuclear Reactions", ibid.
H. Harakawa, J. Kawarada, T. Bamba, Y. Saito,
K. Kimura, S. Ambe, Y. Ohkubo, Y. Kobayashi,
M. Iwamoto, H. Maeda, M. Yanokura, and F.
Ambe: "Determination of Elements Distribution for
NAFION Resin by Using Multitracer Solution", ibid.
S. Shibata, K. Watari, Y. Noda, S. Ambe, Y. Ohkubo,
M. Iwamoto, Y. Kobayashi, M. Yanokura, H. Maeda,
and F. Ambe: "Adsorption Behavior of Various Elements in Chloride Solutions of Multitracer Prepared from Ag Target on Non-ionic Macro-reticular
Copolymer and Activated Carbon Fiber", ibid.
Y. Minai, Y. Takahashi, H. Ohtsuka, M. Ishibashi,
S. Ambe, Y. Kobayashi, Y. Ohkubo, M. Iwamoto,
M. Yanokura, H. Maeda, S. Shibata, N. Takematsu,
F. Ambe, and T. Tominaga: "Multitracer Studyon Interaction between Humic Substance and Metal
Ions", ibid.
S. Ambe, Y. Ohkubo, Y. Kobayashi, M. Iwamoto, H.
Maeda, M. Yanokura, and F. Ambe: "Multitracer
Study on Transport and Distribution of Metal-Ionsin Plants", ibid.

H. Tatsuzaki, T. Okumura, H. Takahashi, M.
Miyakawa, T. Kanai, S. Minohara, M. Sudou, andF. Yatagai: "The Irradiated Volume Dependency of
Early Skin Reaction after Carbon Ion Beam Irradiation", 3rd Workshop on Physical and BiologicalResearch with Heavy Ions, Chiba, Sept. (1993).
F. Yatagai, K. Nakano, T. Kanai, K. Saito, and F.
Hanaoka: "Sensitivity of ts85 Mutant Strain from
Mouse FM3A Cells to Heavy Ions", ibid.
K. Ogura, T. Doke, T. Hayashi, T. Kojima, M.
Matsushima, S. Nagaoka, K. Nakano, T. Takahashi,
H. Yamada, and F. Yatagai: "Tracking and LET
Measurements of Cosmic Ray Nuclei for Space Radiobiological Studies", ibid.
T. Doke, T. Hayashi, R. Takeuchi, K. Ogura, and S.
Nagaoka: "LET-Distribution on Space Shuttle IML1 and FMPT Missions", 1993 Fall Meet. Jpn. Soc.
Appl. Phys., Sapporo, Sept. (1993).
Y. Itoh, H. Murakami, and A. Kinoshita: "Characterization of Porous Silicon by Means of Positron Annihilation II" , ibid.
Y. Minai, Y. Takahashi, M. Ishibashi, T. Ohta, S.
Ambe, Y. Kobayashi, Y. Ohkubo, M. Iwamoto, M.
Yanokura, H. Maeda, N. Takematsu, F. Ambe, andT. Tominaga: "Application of Multitracer Techniqueto Evaluation of Complexation Ability of Humic
Acid" , Ann. Meet. Geochem. Soc. Jpn., Osaka, Sept.
(1993).
T. Kobayashi, T. Nozaki, M. Yanokura, and M.
Aratani: "Ion Beam Analysis and RI Tracer Methodof the Observation of Cation Exchange in Glass
Surface Layers", 37th Symp. on Radiochemistry,
Kanazawa, Oct. (1993).
J. Kurachi, E. Taniguchi, A. Shinohara, M. Furukawa,
S. Kojima, Y. Ohkubo, F. Ambe, K. Takesako, T.
Saito, H. Baba, and S. Shibata: "Competition between Fission and Spallation in the Reactions Induced by Intermediate Energy Heavy Ions", ibid.
K. Takesako, T. Saito, S. Watanabe, A. Yokoyama,
H. Baba, Y. Ohkubo, A. Shinohara, E. Taniguchi,
and M. Furukawa: "Transition to Limiting Behavior
in Heavy-Ion Reactions Exhibited at Intermediate
Energies", ibid.
M. Kiriu, A. Yokoyama, K. Takesako, S. Watanabe, N.
Takahashi, T. Saito, H. Baba, and Y. Ohkubo: "Dependence of Mass Transfer in the Heavy Ion Reaction
on the Mass Asymmetry at Entrance Channel", ibid.
S. Ambe, K. Takeshita, Y. Ohkubo, Y. Kobayashi, H.
Maeda, M. Iwamoto, M. Yanokura, and F. Ambe:"Study of Adsorption of Metal Ions on a-Fe203 Using a Multitracer", ibid.
N. Aoki, T. Bamba, H. Harakawa, Y. Saito, K. Kimura,
S. Ambe, Y. Ohkubo, Y. Kobayashi, M. Iwamoto,
H. Maeda, M. Yanokura, and F. Ambe: "Study on
the Ion Exchange Adsorption of Various Elements on
Superacid Resin NAFION Using a Multitracer III" ,ibid.
S. Shibata, K. Watari, Y. Noda, S. Ambe, Y. Ohkubo,

M. Iwamoto, Y. Kobayashi, M. Yanokura, H. Maeda,
and F. Ambe: "Adsorption Behavior of Various Elements on Non-ionic Macro-reticular Copolymer in
Chloride Solutions Using Radio-active Multitracer",
ibid.
W. Li, Y. Ohkubo, S. Ambe, Y. Kobayashi, M.
Iwamoto, H. Maeda, and F. Ambe: "Study of the
Products from Reactions Induced by Secondary Fast
Neutrons in Intermediate Energy Heavy Ion Collisions", ibid.
Y. Kobayashi, Y. Yoshida, R. Sielemann, L. Wende,
and F. Ambe: "Chemical Behavior of 57Fe Atoms in
Polytetrafiuoroethylene by in-beam Mossbauer Spectroscopy", ibid.
Y. Itoh, H. Murakami, and A. Kinoshita: "Positronium Formation in Porous Silicon", ibid.
M. Iwamoto, S. Ambe, Y. Ohkubo, Y. Kobayashi, M.
Yanokura, and F. Ambe: "Production of Multitracer
Nuclides by Irradiation with 84 Kr Beam", ibid.
H. Ohtsuka, Y. Minai, S. Ambe, Y. Takahashi, M.
Ishibashi, Y. Kobayashi, Y. Ohkubo, M. Iwamoto,
M. Yanokura, H. Maeda, F. Ambe, and T. Tominaga:"Group Separation of Lanthanides from Multitracer
Solution", ibid.
Y. Kobayashi, S. Ambe, K. Takeshita, Y. Ohkubo, H.
Maeda, M. Iwamoto, M. Yanokura, and F. Ambe:"Application of a Multitracer to Solvent Extraction",
ibid.
T. Yaita, S. Tachimori, S. Ambe, Y. Kobayashi, Y.
Ohkubo, H. Maeda, M. Iwamoto, M. Yanokura, and
F. Ambe: "Study on the Solvent Extraction of Various Elements with Diphosphine Dioxide (DPDO)
from Nitric Acid Solution by Use of Multitracer",
ibid.
N. Kubota et al.: "Response of Human Tumor Cells
Grown as Plateau Phase and Multicellular Spheroids
to Carbon Beam Irradiation", 36th Ann. Meet. Jpn.
Radiat. Res. Soc., Hiroshima, Oct. (1993).
H. Ohara, M. Minamihisamatsu, K. Fukutsu, H.
Itsukaichi, K. Kasai, T. Kanai, F. Yatagai, and K.
Sato: "Effects of 135 MeV In of Carbon Ion Beams
Produced by RIKEN Ring Cyclotron on Human
Blood Chromosomes", ibid.
H. Tatsuzaki, T. Okumura, H. Takahashi, M.
Miyakawa, T. Kanai, S. Minohara, M. Sudou, F.
Yatagai: "The Effects of Irradiated Volume on Early
Skin Reaction after Carbon Ion Beam Irradiation",
ibid.
K. Ando, S. Koike, K. Fukutsu, T. Aruga, M. Iizuka,
N. Hori, T. Kanai, and K. Shirasuna: "Increase of
Mitotic Indices in a Human Salivary Gland Tumor
Xenograft after Irradiation with Particle Beams",
ibid.
M. Suzuki, M. Watanabe, Y. Kase, T. Kanai, F.
Yatagai, T. Kato, and S. Matsubara: "The Effectsof Cell Death and Mutation Induction Irradiatedwith Accelerated Carbon Ion Beams with Spread out
Bragg Peak", ibid.
185

Y. Kase, M. Suzuki, T. Kanai, H. Yatagai, T. Katoh,and M. Watanabe: "LET Dependence of Biological
Effects in Normal Human Cells Irradiated with Accelerated Neon Ions", ibid.
F. Yatagai: "Analysis of Biological Damages Induced
by Heavy Ions", RIKEN Symp. on Researches on
Solili State Physics and Materials, Atomic Physics,
Nuclear Chemistry, and Biology and Medicine Using
RIKEN Ring Cyclotron VII. The Next Heavy-Ion
Accelerator Project, Wako, Oct. (1993).
Y. Kobayashi, H. Maeda, and Y. Ohkubo: "Study on
Hyperfine Interaction by Means of Unstable-nuclei
Beam with High Intensity", ibid.
S. Tsubouchi, F. Yatagai, H. Oohara, and E. Kano:"Relative Biological Effectiveness (RBE) of 30 MeV
Neutron and 135 MeV Carbon Beams as Observedby Acute Cell Death (Pyknosis) of Pancreatic Isletof Golden Hamster", 52nd Ann. Meet. of JapaneseCancer Research, Sendai, Oct. (1993).
K. Kimura, T. Shiba, and Y. Sahara: "Effect of theHigh-density Excitation on Luminescence of the Selftrapped Exciton in BaF 2", 1993 Fall Meet. Phys.
Soc. Jpn., Okayama, Oct. (1993).
K. Kimua, T. Shiba, and Y. Sahara: "Lifetime Shortening of STE Luminescence in BaF 2 Excited at HighDensity and STE-STE Distance-dependent Kinetics", ibid.
H. Murakami, Y. Itoh, and A. Kinosita: "Positronium
Formation in Porous Silicon", ibid.
K. Kimura, Y. Sahara, and T. Shiba: "Quenching Pracesses of Self-trapped Excitons in BaF 2, Excited at
High Density", 36th Conf. Radiat. Chern., Tokyo,
Oct. (1993).
Y. Kobayashi: "Exotic Chemistry by Unstable-nuclei
Beams", KUR Symp. on Material Science by Shortlived RI, Kumatori, Nov. (1993).
S. Ambe, K. Takeshita, Y. Ohkubo, Y. Kobayashi, H.
Maeda, M. Iwamoto, M. Yanokura, and F. Ambe:"Multitracer Study of Adsorption of Metal Elements
on a-Fe203", 7th General Meet. Jpn. Soc. Adsorption, Chiba, Nov. (1993).
S. Shibata, K. Watari, Y. Noda, S. Ambe, Y. Ohkubo,

186

M. Iwamoto, Y. Kobayashi, M. Yanokura, H. Maeda,
and F. Ambe: "Adsorption Behavior of Various Elements on Activated Carbon Fiber in Chloride Solutions Using Radioactive Multitracer", ibid.
N. Kubota et al.: "Response of Human Thmor Cells
to Carbon Beam", 6th Ann. Meet. Jpn. Soc. Ther.
Radiol. Oncol., Fukuoka, Nov. (1993).
S. Koike, K. Ando, M. Iizaka, T. Aruga, T. Kanai,
S. Minohara, M. Sudo, N. Hori, C. C. Koo, andF. Yatagai: "Thmor Growth Delay and Thmor Cell
Kills after Single Doses of Carbon-12", ibid.
5.

Material analysis

K. Matsushita, A. Hirotsune, T. Kikuchi, and K.
Furuya: "Evaluation of Thermal Stability and Statesof Deuterium and Herium in He+ Implanted YIG
Annealed in D 2" , 41st Ann. Meet. of Jpn. Soc. Anal.
Chern., Kyoto, Sept. (1992).
K. Kanazawa, M. Yanokura, and M. Aratani: "Quantitative Measurement of Light Elements on the Surfaceof Vacuum Chamber Materials for Electron Storage
Rings", 36th Symp. on Radiochemistry, Hachioji,Oct. (1992).
J. Kawai and K. Maeda: "Chemical Effects on the
Intensity of Ti K1] (Radiative Auger Satellite) XRay Fluorescence Spectra", 28th Colloq. Spectrascopicum Internationale, York, U.K., June (1993).
J. Kawai and K. Maeda: "Imaging Plate PIXE Spectrometer for Chemical State Analysis", 11th Int.
Conf. on Ion Beam Analysis, Balatonfured, Hungary,
July (1993).
K. Maeda and J. Kawai: "K-LL Radiative Auger Satellite of Ca Zr (Z = 20 40)", 16th Int. Conf. on XRay and Inner-Shell Processes, Debrecen, Hungary,
July (1993).
K. Maeda and J. Kawai: "Chemical Effects on the Ca
K1] and KL,B X-Ray Spectra", ibid.
K. Maeda and J. Kawai: "In-situ Analysis of Liquid
Sample by PIXE" , 11th PIXE Symp., Tsukuba, Oct.
(1993).
f"',J

f"',J

x. LIST OF SYMPOSIA(Jan.- Dec. 1993)
1) 1st Symp. on Theory of Atomic and Molecular Processes
13, 14 Jan., Wako, RIKEN, Atomic Physics Lab.
2) Atomic Physics with Accelerator XII
1 June, Wako, RIKEN, Atomic Physics Lab.
3) Muon 1993 - Muon Catalyzed Fusion
28, 29 Sept., Wako, RIKEN, Metal Physics Lab.
4) Researches on Solid State Physics and Materials, Atomic Physics, Nuclear Chemistry, and Biology andMedicine Using RIKEN Ring Cyclotron VII - The Next Heavy-Ion Accelerator Project
25 Oct. , Wako, RIKEN, Nuclear Chemistry Lab., Metal Physics Lab., Atomic Physics Lab., and Cellular
Physiology Lab.
5) Muon Science 1993 - Medical and Biological Application of Non-destructive Element Analysis Using Muons
10 Dec. , Wako, RIKEN , Metal Physics Lab.
6) 2nd Symp. on Theory of Atomic and Molecular Processes
23,24 Dec. , Wako, RIKEN, Atomic Physics Lab.
7) Int . Workshop on Area Detectors for Synchrotron Radiation Research24- 26 Nov., Harima Science Garden City, SPring-8 Project Team187

XI. LIST OF SEMINARS(Jan.- Dec. 1993)
Radiation Lab., Cyclotron Lab., andLinear Accelerator Lab.

1) E. Suraud, Toulouse Univ. (France), 20 Jan.
"On Stochastic Approaches of Nuclear Dynamics"
2) P. Moller, Los Alamos Natl. Lab. (USA), 25 Jan.
"Recent Nuclear Mass Calculations and Their Use
in r-Process"3) Y. Fujita, Osaka Univ. (Osaka), 9 Feb.
"Experiments Using FRS and ESR at GSI"
4) A. Bonasera, LNS, INFN (Italy), 3 Mar.
"Challenges in Heavy Ion Collisions"
5) D. Stoll, Univ. of Tokyo (Tokyo), 12 May"Continuum Limit and Background Field in QED(1+1)"

Relativistic BUU"
15) T. Otsuka, Univ. of Tokyo (Tokyo), 6 Sept.
"Laboratory-Frame View of Nuclear Rotation"16) R. Brockmann, Mainz Univ. (Germany), 20 Sept.
"Relativistic Many Body Theory of Nuclei"17) G. M. Zinovjev, Acad. Sci. of Ukraine (Ukraine),
22 Sept.
"Dissipative Processes in an Expanding Massive
Gluon Gas"
18) H. Nakada, Juntendo Univ. (Chiba), 18 Oct.
"E2 Properties of Nuclei Far from Stability and
the Proton-Halo Problem of BB"20) R. Casten, BNL (USA), 25 Oct.
"Universal Correlations of Nuclear Observables:
A Possible Synthesis of Structural Evolution"6) T. Suomijarvi, Univ. of Paris (France), 25 May"The Study of the Giant Dipole Resonance Built
on the Continuum States with the MEDEA Multidetector"21) D. Youngblood, Texas A&M Univ. (USA), 4 Nov.
"Nuclear Compressibility from the Giant
Monopole Resonance"7) R. Wada, Texas A&M Univ. (USA), 11 June
"Reaction Dynamics in Cu +Au at 35 A MeV"

22) J. Galin, GANIL (France), 12 Nov.
"Hot Nuclei Close to Their Limit of Stability"

8) T. Marumori, Sci. Univ. of Tokyo (Tokyo), 23
June"Microscopic Theory of Collective Motion in One
Particle Level Crossing Region"23) A. Zilges, Univ. of Koln (Germany), 15 Nov.
"Photon Scattering Experiments - A New Approach to Low Lying Collective Excitations"9) Y. Nishino, RCNP, Osaka Univ. (Osaka), 28 June
"Structure Functions of Hadrons in the QCD Sum
Rules"
10) J. Janecke, Univ. of Michigan (USA), 29 June
"Study of Giant Resonances with eHe,t) andeLi, 7Be) Charge Exchange Reactions"11) A. Sakai, Yamagata Univ. (Yamagata), 5 July
"Quark Confinement and Number of Flavors in a
Lattice QCD with Wilson Quarks"12) R. Boyd, Ohio State Univ. (USA) , 26 July
"Radioactive Beam Measurements in Astrophysics"13) J. Kolata, Univ. of Notre-Dame (USA), 27 July
"Elastic Scattering and Fragmentation of 12, 14 Be"
14) T. Maruyama, Kyoto Univ. (Kyoto), 23 Aug.
"Study of High Energy Heavy Ion Reactions by
18824) M. Petrascu, lAP (Rumania), 25 Nov.
"Projectile Breakup Mechanism in Light Nuclear
Systems"25) S. Okabe, Hokkaido Univ. (Sapporo), 29 Nov.
"Visualization of Nuclear Reactions - A Computer Simulation of Quantum Systems by Molecular Dynamics"
26) J. N. De, VECC (India) , 13 Dec.
"Limiting Temperature in Finite Nuclei"27) D. Beaumel, ORSAY (France), 27 Dec.
"Neutron Decay Studies of Giant States with the
ED EN Multidetector"
Atomic Physics Lab.

1) B. D. DePaola, Kansas State Univ. (USA), 12 Jan.
"Charge Transfer Experiments Using LaserExcited Targets"

2) V. I. Zoran, Inst. Phys. Nucl. Eng. (Rumania),
21 Jan.
'''Defreezing' the Target Electron Wave Function
in Swift Asymmetric Collision (Breathing, RotaC oup l'mg, ... )"·t lOn,

3) K. H. Lieser, T. H. Darmstadt (Germany), 15
Mar.
"Speciation, a Challenge to Analytical Chemistry"4) G. F. Hermann, Mainz Univ. (Germany), 15 Oct.
3) M. Kimura, ANL (USA), 12 Mar.
"Chemical Effects in Molecular Photoabsorption
and Photoemission"4) R. Schuch, MSI (Sweden), 19 Mar.
"Experiments with Cold Ions and Electrons in the
Stockholm Storage Ring""Super heavy Elements - Could We Still Find
Them?"
5) K. Morita, RIKEN, (Saitama), 15 Oct.
"A Search for Super Heavy Elements with Use of(HI,axn) Reactions"6) H. HaBlein, Shizuoka Inst. Sci. Tech. (Shizuoka),
5) L. Spielberger, Univ. of Frankfurt (Germany), 7
Apr.
"First Result in the Impact Parameter Dependent
Investigation of Ionization and Charge Transfers
in 1.05 MeV /amu 0 6 + -7 Ar Collisions"
6) V. McKoy, Dept. of Chemistry, Cal. Tech. (USA),
26 May"Studies of Electron-Molecule Collisions on
Highly Parallel Computers"7) W. Eissner, The Queen's Univ. (UK), 2 June
"Inner-Shell
Photoionization
Calculations- Applications to Be and Na-"8) Y. Azuma, ANL (USA), 13 Sept.
"The Trend of Atomic Physics by Synchrotron Radiation in the U.S."9)

I. Martinson, Univ. of Lund (Sweden), 28 Oct.

"Spectroscopy of Highly Charged Ion at University of Lund"
10) Z. G. Zhi, Univ. of Electro-Communications(Tokyo), 28 Oct.
"N0- Linear Optical Process Using ElectroMagnetically Induced Transparency"

11) J. Z. Tang, RIKEN, (Saitama), 16 Dec.
"Photoionization of He from Excited States"

19 Nov.
"Intrinsic Defect in Germanium Studied by
Pertur bed-Angular-Correlation"

Synchrotron Radiation Facility Design Group
1) H. Hama, UVSOR (Aichi), 25 June
"A Control System of UVSOR-Ring and Its Application for the Low a Operation"2) T. Kawakubo, KEK (Ibaragi), 19 July"A Profile Monitor with MCP"

3) H. Sumiyoshi, Matsusho-Gakuen Junior College(Nagano), 10 Aug.
"A New Simulation Code for High-Energy Multiple Collisions"4) M. Tejima, KEK (Ibargi), 2 Sept.
"Single Pass Monitor"

5) A. Taketani, Fermi Nat. Acc. Lab. (USA), 10 Sept.
"Measurement of Asymmetry Rate of Muons from
W-Bosons in Proton-Antiproton Collisions at 1.8
TeV"6) C. Zhang, NSRL (China), 16 Sept.
"Alignment Networks for NSRL and the Magnets'
Planar Position"

Nuclear Chemistry Lab.

7) T. Nagae, UVSOR (Aichi), 30 Sept.
"Development of Micro-Strip Gas Chamber"

1) W. Li, Inst. Modern Phys. (China), 4 Mar.
"Radiochemical Study of Heavy-Ion Reactions inIMP"8) Y. Tsusaka, Nagoya Univ. (Aichi), 15 Oct.
"Development of an X-Ray Telescope for AstronomicalObservations"2) A. Shinohara, Nagoya Univ. (Nagoya), 4 Mar.
"N uclear Chemical Studies on IntermediateEnergy Heavy-Ion Reactions"9) N. Liu, NSRL (China), 8 Nov.
"Status of Hefei National Synchrotron Radiation
Laboratory"

189

XII.

LIST OF PERSONNELRIKEN Accelerator Research Facility
ISHIHARA Masayasu 1:] JJ lE ~ (Facility Director)
AWAYA Yohko ~ ~ ?§. -r (Vice Facility Director)
YANO Yasushige
If ti: ~ (Vice Facility Director)*

Linac Division
CHIBA Toshiya =f ~ llJ 'fiJG
HEMMI Masatake i! Je. ~ it
KASE Masayuki 110 i¥Ji l§ Z
MIYAZAWA Yoshitoshi g if{ 1* fit*=*=

CHIBA Yoshiaki =f ~ ff f3JJ
IKEZAWA Eiji W! if{
KOHARA Shigeo /J\ JJ ~ X

Ring Cyclotron Division
FUJITA Jirou Jii.e~
IKEGAMI Kumio ~-f!Ll::JL-=-~KAGEYAMA Tadashi J~ tlJ lE
KASE Masayuki 110 ifi l§ Z
KUBO Toshiyuki ~ 1* fit $:NAKAGAWA Takahide q:r )11 q: ~YOKOYAMA Ichiro ;fl tlJ - .e~

GOTO Akira 1& Jii ~ *INABE Naohito fIB J!l ~ A
KAMIGAITO Osamu J:.j:}[ j1-fl~ ­KOHARA Shigeo /J\ JJ ~ X
NAGASE Makoto ~ i¥Ji ID£
OGIWARA Kiyoshi M( JJ

Experimental Support Division
ICHIHARA Takashi
JJ !j!
KANAI Yasuyuki ~ 1f 1* Z
KUMAGAI Hidekazu :fi~:fr ~ fD
MORITA Kosuke ~ 83
11WATANABE Yasushi at ~ Jl
YATAGAI Fumio :fr.B3JtXX

KAMBARA Tadashi 1$ JJ iE
KOBAYASHI Toshio /J\;t* @: ~t*
MATSUZAKI Teiichiro :m~t~m.eB
OHKUBO Yoshitaka *~1*~ ~YANOKURA Minoru ~If:§ ~Radioisotope Facilities Division
AMBE Fumitoshi ti: {fB :X fit*
KOBAYASHI Yoshio /J\;t*. ~IWAMOTO Masako:fiRadiation Protection GroupFU JITA Shin Jii 83 ~JT
NAKANISHI Noriyoshi q:r rt§ me %*NAKAJIMA Shunji'i=' ~ ~*

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Secretariat
NAKAMURA Toshiko

q:r f;j" t L-r

Steering Committee
AMBE Fumitoshi ti: $ :X fit
CHIBA Yoshiaki =f ~ ~f f3JJ
HANAOKA Fumio 1E IiYiJ Jt ~t
ISHIHARA Masayasu 1:] JJ lE ~KATSUMATA Koichi JWj X *11: KOBAYASHI Toshio /J\ *~ f~ ~t
MATSUOKA Masaru
IiYiJ
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NAGAMINE Kanetada 71< ~ ~ ,~\TAKAMI Michio rWJ Je. J!! 1::
YAGI Eiichi )\
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* Group Leader, ** Manager, *** Chairperson

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YOSHIDA Tohru

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AWAYA Yohko ~ ~ ?§. -r
GOTO Akira 1& Jii ~INAMURA Takashi T. fIB f;j" !j!
KAMITSUBO Hiromichi J:.:!if
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KIRA Akira~~
KUMAGAI Noritaka :fi~:fr ~ q:
MIYAZAWA Yoshitoshi g if{ 1:£ fit
TAKAHASHI Tan rWJ ~ H
TANIHATA Isao :fr. j:ffi JJj X***YANO Yasushige
If ti: 1i*a*Scientific and Engineering Personnel

Cosmic Radiation Laboratory
IMAI Takashi 4- 1t: ~KOHNO Tsuyoshi?ilJ!f~~(Visitors)
HASEBE Nobuyuki ~:fr:g~lli1T (Fac. Gen. Educ., Ehime Univ.)
KASHIWAGI Toshisuke ~B
flJ fI (Fac. Eng., Kanagawa Univ.)
KATO Chihiro 1m iii =f ~ (Fac. Sci., Shinshu Univ.)
MUNAKATA Kazuoki
it. - j@ (Fac. Sci., Shinshu Univ.)(Fac. Sci., Rikkyo Univ.)
MURAKAMI Hiroyuki ft -'=- ~11r L
NAGATA Katsuaki 7"1< EEl 1m IlJJ (Fac. Eng., Tamagawa Univ.)
NAKAMOTO Atsushi ~~*(Fac. Sci., Rikkyo Univ.)(Fac. Sci. , Rikkyo Univ.)
YANAGIMACHI Tomoki fgn!BY JV1

*

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(Students)
FUJIKI Kenichi iii~(Fac. Sci., Ehime Univ.)
ITO Tomoyuki 1ft iii J1Jj 1T (Fac. Sci. Eng., Waseda Univ .)ITSUMI Norifumi ~ Jt '-!t!. ~ (Fac. Sci. Eng., Waseda Univ.)
SHINO Tomoaki fi ~ ~ (Fac. Sci. Eng., Waseda Univ.)* -=Cyclotron Laboratory
FUJITA Jirou iii EEl.M
GOTO Akira 1& iii ~***INABE Naohito
ill fo1 A
KAGEYAMA Tadashi J~ W if.
KITAGAWA Hisashi ~t )I[
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KUBO Toshiyuki !A... 1* #ill ¥NAGASE Makoto ~ if! ~NAKAJIMA Shunji ~ ~ ~~OGIWARA Kiyoshi W< ~ ~w
OTSUKA Takaharu
q: 18**SUZUKI Toshio jit
fit ~ **WAKASUGI Masanori =ff ~ {§ f~
YAN 0 Yasushige
ff ~ :i: *m=*"* ±*** Chief Scientist,** Visiting Advisory Scientist,

FUJITA Shin iii EEl ~Jf
IKEGAMI Kumio H!!.j:J1 ~ ~JIN Weiguo -it ~ 00
KAMIGAITO Osamu -,=-tl3j}fl~­
KOHARA Shigeo /J\ ~ :i:
MORITA Kosuke ~ EEl ~i1f 1tNAKAGAWA Takahide ~)II q: ~NAKANISHI Noriyoshi ~ g§
OHTA Shigemi
EEl i:tt 1::
SUGANUMA Hideo if ~B ~UESAKA Tomohiro -'=-:l:R 1X ~$YAMAJI Shuhei W ~ fl~ Jf***
YOKOYAMA Ichiro :ft w - .M

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*

***Senior Scientist(Visitors)
ABE Yasuhisa ~ilJ:g~ $ 7-.. (Uzi Res. Cent., Yukawa Inst. Theor. Phys., Kyoto Univ.)
PI.M (NASDA)
AOKI Shirou 1f
ARAI Eiichi ~Jf 1t: 5R (Res. Lab. Nucl. Reactors, Tokyo lnst. Technol.)(JAERI , Takasaki)
ARAKAWA Kazuo Jit )I[ toEJIRI Hiroyasu ~I JK~(Dept. Phys., Osaka Univ.)
ENYO Hideto ~ --9- ~ A (Dept. Phys., Kyoto Univ.)
FUJIOKA Manabu iii rml ~ (Cyclotron Radioisot. Cent. , Tohoku Univ.)
FUJISAWA Takashi iii i,R rWJ is (Denki Kogyo Co. Ltd.)
FUJITA Yoshitaka iii EEl 11 q: (Dept. Phys., Osaka Univ.)
FUJIWARA Ma:m.oru Jli ~ ~ (RCNP, Osaka Univ.)
FUKUDA Mitsuhiro m; EEl 1t(JAERI, Tokai)
FUKUMOTO Sadayoshi m;~ ~(Univ. Tsukuba)
FURUNO Kohei l!l ff ~ Jf (Inst. Phys. Tandem Accel. Cent., Univ. Tsukuba)
HAMA Hiroyuki ~ rt:. ¥(LM.S.)HASHIMOTO Osamu
18 (lnst. Nucl. Study, Univ. Tokyo)
HATA Kazuo ~ to(Fac. Eng., Kyoto Univ.)
HATANAKA Kichiji m ~ s 18 (RCNP, Osaka Univ .)

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191

HATSUKAWA Yuichi :rJJ )1/ ~l (JAERI, Tokai)
HATTORI Toshiyuki m~ $ {~¥ (Res. Lab. Nucl. Reac., T.I.T.)
HAYANO Ryugo .!f!. ff If~ 1i (Dept. Phys., Univ. Tokyo)
HEIGUTI Kazuhiko .lfZ IJ fD jffi (Graduate Sch. Sci. Technol., Niigata Univ.)
HIRAO Yasuo .lfZ If:. ~ ~ (NIRS)HONMA Toshihiro~]A(Cyclotron Radioisot. Cent., Tohoku Univ.)
HORIBATA Takatoshi t}ffi!lffij 4 {~ (Fac. Eng., Aomori Univ.)
HORIGUTI Takayoshi ~ IJ ~i.Ii! (Dept. Phys., Hiroshima Univ.)
HORIUCHI Hisashi ~pqU~ L (Dept. Phys., Kyoto Univ.)
HOSONO Kazuhiko *IB ff fD ffi (RCNP, Osaka Univ.)
IGARASHI Toshio 1i ltfixil (NASDA)~(Dept. Phys., Niigata Univ .)IKEDA Kiyomi ~-t!l. 00
IKEDA Nobuo at!. IE 1$ X (Inst. Nucl. Study, Univ. Tokyo)
IKEGAMI Hidetsugu at!. J::. 5R mL (RCNP, Osaka Univ.)
IKEZOE Hiroshi ~-t!l. ~ tf (JAERI, Tokai)
IMAI Kenichi A,
E (Dept. Phys., Kyoto Univ.)
INOUE Makoto
J::. 1§ (Inst. Chern. Res., Kyoto Univ.)
ISHII Takayuki ;fj
4 ¥ (NASDA)
ISHIZUKA Takeo ~ ±j( it ~ (Dept. Phys., Saitama Univ.)
BB (JAERI, Tokai)
IWAMOTO Akira :E
IWASHITA Yoshihisa :fi r 7f!A (Inst. Chern. Res., Kyoto Univ.)
KAJI Harumi ~ dE
HiJ (Fac. Eng., Tohoku Univ.)
KAMEYAMA Hirobumi __ W Hi)( (Dept. Phys., Chiba Keizai Jr. ColI.)
KAMIMURA Masayasu J::.;t;j" iE Jl (Dept. Phys., Kyushu Univ.)
KANAZAWA Mitsutaka ~ ~ J\': ~i (NIRS)
KANMURI Tetsuo jtf ~ X (Dept. Phys., Osaka Univ.)
KANNO Tooru 'if ff 11& (NASDA)
KATAYAMA Ichirou }t W -.M (Inst. Nucl. Study, Univ. Tokyo)
KATAYAMA Takeshi h W it P] (lnst. Nucl. Study, Univ. Tokyo)
KATO Kiyoshi 110 Hi ~ 7f (Dept. Phys., Hokkaido Univ.)
KATORI Kenji 1&~(Dept. Phys., Osaka Univ.)
KATOU Shouhei 11D Jii l§ f
(Dept. Phys., Osaka Univ.)
KATSURAGAWA Hidetsugu II )1/ ~ RBPJ (Dept. Phys., Toho Univ.)
KAWAI Mitsuji fiiJ 1} J\': ~ (Dept. Phys., Kyushu Univ.)
KIKUCHI Fumio *i at!. )( ~ (ColI. Arts Sci., Univ. Tokyo)
KOHMOTO Toshiro iilJ
fix.M (Dept. Phys., Kyoto Univ.)
KONDOU Michiya :ilL Jii :@ -tl! (RCNP, Osaka Univ.)
KOSAKO Toshiso /J'\ftr.t1fixft: (Atomic Energy Res. Cent., Univ. Tokyo)
KOTAJIMA Hisaya t1IE~!Ai& (Fac. Eng., Tohoku Univ.)
KUBOYAMA Tomoji !AHRw~P] (NASDA)
KUDO Hisaaki I iii !A Bg (Dept. Chern., Niigata Univ.)
KUROYANAGI Tokihiro ~tpn1t%* (Dept. Phys., Kyushu Univ.)
LEE Sang Moo;f13(Inst. Phys., Univ. Tsukuba)
MARUMORI Toshio J.t ~ ~ X (Fac. Sci. Technol., Sci. Univ. Tokyo)
MATSUDA Sumio ~ IE *41. X (NASDA)
MATSUI Yoshiko ~7f -f- (Fac. Tech., Tokyo Univ. Agri. Tech.)
MATSUKI Seishi ~fiE 31:. (RCNP, Osaka Univ.)
MATSUSE Takehiro ~ iii 5: Hi (Dept. Phys., Shinshu Univ.)(Dept. Phys., Kyoto Univ.)
MATSUYANAGI Kenichi ~ tpn :pJf MIAKE Yasurou
IIjJ Jl.M(Inst. Phys., Univ. Tsukuba)
MIDORIKAWA Shouichi *'~ )1/ :!f (Dept. Market, Meiji Univ.)
MINAMISONO Tadanori
iii J~' .QIJ (Dept. Phys., Osaka Univ.)
MIURA lwao~m:fi (RCNP, Osaka Univ.)
MIYAMURA Osamu g;t;j" fl~ (Fac. Sci., Osaka Univ.)
MIYATAKE Hiroari g it ~ -tl! (Fac. Sci., Osaka Univ.)
MIZOTA Takeshi il IE it ~ (Inst. Phys., Univ. Tsukuba)
MIZUNO Yoshiyuki 7}c ff ~ Z.
(RCNP, Osaka Univ.)
MORI Yoshiharu ~ ~ rs (KEK)

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MURAKAMI Tetsuya ~1 -'=- :gr 111 (Dept. Phys., Kyoto Univ.)
MURAOKA Mitsuo ~11iYiJ -Jt ~ (Dept. Educ., Chiba Univ.)
MURAYAMA Toshiyuki ~1 W ~IJ ¥(Tokyo U niv. Mercantile Marine)
MUROTANI Shin ~:fr {,I (Sch. Sci. Eng., Waseda Univ.)
NAGAI Yasuki 71< 1f ~ W (Dept. Appl. Phys., Tokyo Inst. Technol.)(NASDA)NAITOU Ichirou rg »i - BB
NAKAHARA Hiromichi 9=t!* 51..:ii (Dept. Chern. , Tokyo Metrop. Univ.)
NAKAI Koji 9=t 1f Hi(KEK)
NAKAJIMA Masato 9=t ~ • A(NASDA)BB (Dept. Phys., Saitama Univ.)
NAKAMURA Ichiro 9=t ~1
NAKAMURA Takashi 9=t ~1 r61 -m (Cyclotron Radioisot. Cent., Tohoku Univ.)
NIITA Koji t1t83~= (Dept. Phys. , Univ. Giessen, Germany)(Inst. Nucl. Study, Univ. Tokyo)
NODA Akira !f 83 •NODA Kouji !f 83 fJt -m (NIRS)NOMURA Toru !f 11 7- (Inst. Nucl. Study, Univ. Tokyo)
OGATA Hiroshi IJ\ 11 'J[ (RCNP, Osaka Univ .)OGAWA Kengo IJ\ )I[ f,t -jg- (Fac. Educ. , Chiba Univ.)
OKABE Shigetou IiYiJ $ fiX. ~ (Center Inf. Proc. Educ., Hokkaido Univ.)
OKAMURA Hiroyuki IiYiJ ~1 51.. Z (Dept. Phys., Univ. Tokyo)
OKUMURA Susumu ~ ~1 :itt (JAERI, Takasaki)g§ il ~l(Dept. Phys., ColI. Arts Sci. , Univ. Tokyo)
ONISHI Naoki
OOHIRA HideharuY§ ff (NASDA)
OOTSUKI Tsutomu
ftJl. ifJ (Lab. Nucl. Sci. , Tohoku Univ.)OOURA Akio
ii Bg X (NASDA)*. BB (NASDA)OOYA Jirou
OSUGA Toshiaki "*~J{~fit13JI (ColI. Arts Sci. , Chiba Univ.)
PU Yuehu 1i ~ dE (Inst. Nucl. Study, Univ. Tokyo)
SAGARA Kenji ~§ ~ Jt! ~ (Dept. Phys. , Kyushu Univ.)
SAKAI Hideyuki 1~ 1=1= ~ 1T (Dept. Phys. , Univ. Tokyo)
SASAGAWA Tatsuya iff )I[ lIZ ~t (Dept. Phys. , Tohoku Univ.)
SATO Yukio 1tc »i ¥ X (NIRS)(Dept. Phys., Tohoku Coll. Pharm.)
SATOU Kenichi 1tc »i j! SATOU Kenji 1tc »i f,t(NIRS)SEKINE Toshiaki ~ tN {~13JI (JAERI, Tokai)
SHIBATA Tokushi ~ 83 :f1@ lE!, (Inst. Nucl. Study, Univ. Tokyo)
SHIKAZONO Naoki 1& IE il ~ (JAERI, Tokai)
SHIMANO Yosuke 1lJ.~ If ~$ 1r (NASDA)
7,1(
Bg (RCNP, Osaka Univ.)
SHIMIZU Akira
SHIMOMURA Koichiro p~1 ~- BB (Meson Sci. Lab., KEK Brunch, Univ. Tokyo)
SHINOZUKA Tsutomu fJi ±j( 1m (Cyclotron Radioisot. Cent. , Tohoku Univ.)
SHIRAI Toshiyuki B 1t fit Z (Res. Inst. Fundam. Phys. , Kyoto Univ.)
SUEKI Keisuke~ 1r(Inst. Nuel. Study, Univ. Tokyo)
SUGAIIsao 'if 1=1= wn (Inst. Nuel. Study, Univ. Tokyo)
fit (NASDA)
SUGIYAMA Hiroki ~ W
SUMIYOSHI Hiroyuki it i§" J1;. 1T (Matsusho-Gakuen Jr. Coll.)
TAGISHI Yoshihiro EE J$ •(Tandem Aeeel. Cent. , Univ. Tsukuba)
TAKADA Kenjiro ~83f,t*BB (Dept. Phys., Kyushu Univ.)
TAKEMASA Tadashi ~ i& ~ ± (Dept. Phys. , Saga Univ.)
TAKEUCHI SuehirorgJ1;. (JAERI , Tokai)
TAKIGAWA Noboru it )1/ 1l- (Dept. Phys. , Tohoku Univ.)
TAMAGAKI Ryozo :E. :f::g ~(Dept. Phys. , Kyoto Univ.)
TAMURA Takashi 83 ~1 ~ ~ (NASDA)
TANAKA Jiniehi 83 9=t t(Inst. Nucl. Study, Univ. Tokyo)
TOKI Hiroshi ± Ill.! tf (Dept. Phys. , Tokyo Metrop. Univ.)
TOMIMASU Takio i;~ $ :@:x
(FEL Res. Inst. Inc.)TOMITANI Takehiro i;:fr:fElt Hi (NIRS)TOMOTA Toshiaki 15.. B3 fit .
(Fac. Eng. , Aomori Univ.)
TORIYAMA Tamotsu ,~LlJ 1* (Dept. Appl. Phys. , Tokyo Inst. Technol.)

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TSUNEMOTO Hiroshi '/1I 5I: tf (NIRS)UESUGI Masato 1::. ~ iE A (NASDA)
UWAMINO Yoshitomo 1::. it • AA (Inst. Nucl. Study, Univ. Tokyo)
WADA Michiharu ~O EI3 :@:?s (Dept. Phys., Tohoku Univ.)
iE:@: (Dept. Phys., Osaka Univ.)
WAKAI Masamichi =fi
WAKUTA Yoshihisa ~O~B3.~ (Fac. Eng., Kyushu Univ.)~(Inst. Modern Phys., Acad. Sinica, China)
WANG Zhen ~YAMANOUCHI Mikio LlJ IAJ ~ ~l (Tandem Accel. Cent., Univ. Tsukuba)
YAMADA Taiichi LlJ EI3 ~ (Dept. Phys., Kochi Women's Univ.)
YAMAMOTO Yasuo LlJ
ti: X (Tsuru Univ.)(RCNP, Osaka Univ.)
YAMAZAKI Takashi LlJ ~YAZAKI Koichi
dffif M: (Dept. Phys. , Univ. Tokyo)
83 ~ iii (Dept. Phys., Univ. Tokyo)
YOSHIDA Nobuaki
YOSHIDA Shiro S EEl }~',.M (Dept. Phys. , Ishinomaki Senshu Univ.)
YOSHINAGA Naotaka S 71< r&1 q: (Dept. Phys., Saitama Univ.)
YOSHIOKA Yasuhiro S IiYiJ * 51 (NASDA)~(ColI. Ind. Technol.)
YOSHIZAWA Yasukazu S iR

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(Students)
IE ~ (Dept. Phys., Tohoku Univ.)
AOKI Yuka W
ARIGA Takehiro ~ ~ 1m tf (Dept. Phys., Saitama Univ.)
FURUYA Shinji tJ:§. {§ WJ (Dept. Appl. Phys., Tokyo Inst . Technol.)
FUTAMI Yasuyuki
Jr.
Z (Dept. Phys., Univ. Tsukuba)
HAMADA Shingo it EEl ~ fEf (Dept. Nucl. Eng., Kyoto Univ.)
HIRAI Masahide f
1& ~ (Dept. Phys., Sophia Univ.)
HONMA Hiroyuki
rl't~ m Z
(Dept. Phys., Tokyo Inst. Technol.)
INOUE Jirou
1::. ;)(.M (Dept. Phys., Sophia Univ.)
KASHIWABARA Taketo ;fa
1m A (Dept. Phys., Toho Univ.)
KATOU Haruhiko 110 Wi ?s & (Dept. Phys., Chuo Univ.)
KIYONO SatoshiIF;€: (Dept. Appl. Phys., Tokyo Inst. Technol.)(Dept. Phys., Hiroshima Univ.)
KUMAGAI Kenji 1m:§.1I:
MABUCHI Hideyuki ,~i*,J ~ Z(Dept. Phys., Kounan Univ.)
MARUYAMA Toshiki A LlJ $!l ~1 (Dept. Phys., Kyoto Univ.)
MATSUMOTO Norihiro ~#! ~$ (Dept. Phys., Kounan Univ.)
MINEMURA Toshiyuki~t {~1T(Dept. Phys., Chuo Univ.)
MOTOGI Yoshio
X (Dept. Phys., Univ. Tsukuba)
NAKAGAWA Keiko 9=t)ll ~ -f- (Dept. Phys., Tohoku Univ.)
NAKAO Noriaki 9=t ~ it. BBB (Dept. Phys., Tohoku Univ.)
OGAWA Izumi IJ\ }I/ 5R (Dept. Phys., Kyoto Univ.)
dJ*f $!l Jr~(Dept. Appl. Phys., Tokyo Inst. Technol.)
OOSAKI Toshiro
SASAKI Reiji ftc~ *ftj-t (Dept. Phys., Tohoku Univ.)
SATOU Hideko ftc Wi ~ -f- (Dept. Phys., Univ. Tsukuba)
SENOO Kenichi ~ ~ W (Dept. Appl. Phys., Tokyo lnst. Technol.)
SHINOZAKI Akihisa 1Il dffif ~ ~ (Dept. Phys., Tohoku Univ.)(Dept. Phys., Tohoku Univ.)
SUNAOSHI Hitoshi liP:j:!JI t
TAKADA Shinji rWJ EI3 ~ i0 (Dept. Phys., Tohoku Univ.)
TAKAHASHI Takumi rWJ ~ ~ E (Dept. Phys., Chilo Univ.)
TAKEDA Kenji it EEl W i0 (Dept. Appl. Phys. , Tokyo lnst. Technol.)
TANIGAWA Masashi :§. }I/ Jm ~ (Dept. Phys., Tokyo Metrop. Univ.)
TOMITA Shigeo ~ EEl JfX. X (Dept. Phys., Univ. Tsukuba)
TOMOHISA Yasuhiko 1§. ~ f* & (Dept. Phys., Univ. Tsukuba)
UMETSU Youichirou ~~*~~-Jr~ (Dept. Phys., Tohoku Univ.)WAKUI Takashi i~ 1t *;t- (Dept. Phys. , Toho Univ.)
WATANABE Koutarou iJlill**i!~ (Dept. Appl. Phys., Tokyo lnst. Technol.)

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Linear Accelerator Laboratory
CHIBA Toshiya T ~ {IJ t!:!G
FU JIMAKI Masaki Iii:{!: 1£ tM
HIRENZAKI Satoru It:il~ 'l'ff
KASE Masayuki 110 i1i ~ L
KUMAGAI Hidekazu 1m ~ ~ {OOZAWA Akira IJ~ if{ ~J{
TANIHATA Isao ~ j:ffi ~ X*
YANOKURA Minoru *ff~ ~* Chief Scientist,

CHIBA Yoshiaki T ~ ~f IlYJHEMMI Masatake ~ Jt i& it
IKEZAWA Eiji j-tf!. if{
KOBAYASHI Toshio IJ~ t* {~ it**
MIYAZAWA Yoshitoshi g if{ 1:£ fit
SUZUKI Takeshi j1t~
TONUMA Tadao ?
iE it
YOSHIDA Koichi
B3 1t. -a*=*m** Senior Scientist(Visitors)
ALEKSANDROV D. V.
(Kurchatov Inst. , Russia)
BOLBOT Michael D.
(Notre Dame Univ., U.S.A.)
BOYD Richard(Ohio State Univ., U.S.A.)
BROCKMANN Rolf (Inst. Phys. Univ. Mainz, Germany)(CTA, Inst. Estudos Avancados, Brasil)
CARLSON Brett
CHLOUPEK Frank(Ohio State Univ., U.S.A.)
DEMYANOVA Alla S.
(Kurchatov Inst. Atomic Energy, Russia)
FENG Jun t~• (Shanghai Inst. Nucl. Res., China)
FUJIWARA Mamoru Iii Jjji ~ (RCNP, Osaka Univ.)(Fac. Sci., Sci. Univ. Tokyo)
FURUYA Keiichi iJ ~ ~ HIRATA Daisy(CTA, Inst. Estudos Avancados, Brasil)
ITO Noriaki 'fit Jfi '!l! et{ (Dept. Cryst. Mater., Nagoya Univ.)
KANAZAWA Kenichi ~ ~~ 1it (KEK)
KATORI Kenji JJt lfX III(Fac. Sci., Osaka Univ.)
KIKUCHI Jun §lij HlL )Ilfi (Sci. Eng. Res. Lab. , Waseda Univ.)
KIMURA Kikuo *ft%~til (Fac. Eng., Nagasaki Inst. Appl. Sci.)(Notre Dame Univ" U.S.A.)
KOLATA James(Kurchatov Inst., Russia)
KORSHENINNIKOV A. A.
MATSUTA Kensaku t~ $ 1it ~ (Osaka Univ.)
MATUOKA Nobuyuki t~ [tG] 1$ fr (Res. Cent. Nucl. Phys. , Osaka Univ.)
MOCHIZUKI Keiko ~J1 ttl,,)-T' (Osaka Univ.)
MOON Chang-Bun(Seoul Natl. Univ., Korea)
MURAOKA Mitsuo ft [tG] 1t. J} (ColI. Arts Sci. , Chiba Univ.)
NIKOLSKI Evgenini Y.
(Kurchatov Inst., Russia)
NOJIRI Yoichi ff fft. ~-¥: (Osaka Univ.)
OGAWA Kengo IJ~ )11 !it -i§- (ColI. Arts Sci., Chiba Univ.)
OGLOBLIN Alexei A.
(Kurchatov Inst., Russia)
OJIMA Minoru IJ~ IIJ.~ f.fr': (Osaka Univ.)
OMATA Kazuo /J~ f* fO X (Inst. Nucl. Study, Univ. Tokyo)(Ohio State Univ., U.S.A.)RAIMANN Gerhard(Fac. Sci. , Univ. Tokyo)
SAGAWA Hiroyuki ftc )11 51.. ¥fr (Fac. Sci., Univ. Tokyo)
SAKAI Hideyuki ?@SUDA Toshimi JJ! B3 {IJ ~ (Fac. Sci., Tohoku Univ.)
SUGAWARA Masahiko 'if Jjji ~ ffi (Fundam. Sci., Chiba Inst. Technol.)
i1! L (Fac. Sci. Niigata Univ.)
SUZUKI Yasuyuki $~TOKI Hiroshi ± IIJ~ tt (Tokyo Metrop. Univ.)(Osaka Dentist Univ.)
WADA Takahiro fO B3 I!i~(Sci. Eng. Res. Lab., Waseda Univ.)
YAMAGUCHI Hiromi LlJ IJ
ZAHAR Mohamed (Notre Dame Univ., U.S.A.)

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(Students)
FUKUDA Moichi ti B3(Fac. Sci., Osaka Univ.)
HARADA Akihiko ffit EB eg ffi (Fac. Sci., Osaka Univ.)
IZUMIKAWA Takuji 7'J{ )11~(Fac. Sci., Osaka Univ.)(Fac. Sci., Sci. Univ.' Tokyo)
MATSUSHITA Kenichi ~ T 1it -

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195

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MIHARA Mototsugu ~~ HOP](Fac. Sci., Osaka Univ.)~
W (Fac. Sci., Osaka Univ.)
MIYAKE Toru
J{ 11&(Fac. Sci., Tokyo Metrop. Univ.)
MIYAMOTO Shinya g
MOCHIZUKI Keiko "'Jl!. J3 :1: -f- (Fac. Sci., Osaka Univ.)
NAKAZATO Masahisa q:r 1l J{ 7-.. (Fac. Sci. , Osaka Univ.)
OBUTI Marcia (Sci. Technol., Saitama Univ.)
ONISHI Takashi
gg(Fac. Sci., Osaka Univ.)
SASAKI Makoto f~~~(Fac. Sci. , Osaka Univ.)
TANIGAKI Minoru :fr tg ~ (Fac. Sci., Osaka Univ.)
YAMAGUCHI Takayuki LlJ IJ .. Z (Fac. Sci., Osaka Univ.)

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Radiation Laboratory
FUKUNISHI Nobuhisa W; gg ~ fi1D
ISHIHARA Masayasu :fj
if ~*KISHIDA Takashi J¥ EH ~i
MORIKAWA Tsuneyasu ~ )1/ fg ti:
SUZUKI Masayo ~{1l§ iitTANAKA Kazuhiro B3 q:r .to JJ{
WATANABE Yasushi itt ~ rnt

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ICHIHARA Takashi m!i!
IZUMO Koichi l±. ~ jt KONNO Satoshi ~ ff ~NAKAMURA Takashi q:r ~1 ~i P]
TAKAHASHI Tan iWi ~ .fL
TENDOW Yoshihiko 7(. m =Jf ft
YOSHIDA Atsushi
B3a* Chief Scientist(Visitors)
ABE Yasuhisa ~iiJ {f~ $. 7-.. (Res. Inst. Fundam. Phys. , Kyoto Univ.)
ADACHI Minoru JE 1L Jf (Dept. Appl. Phys., Tokyo Inst. Technol.)
ANDO Yoshiaki ti: iii ~::!l (Dept. Phys. , Rikkyo Univ.)
APRILE Elena(Columbia Univ. , U.S.A.)
ASAHI Koichiro :hI! fJj:- .M (Fac. Sci. , Tokyo Inst. Technol.)
BECK F. A.
(Groupe RSN, Strasbourg, France)
BROGLIA R.
(Milano Univ. , Italy)
CASTEN Rick(Brookhaven Natl. Lab. , U.S.A.)
DOKE Tadayoshi :ii
I~' tit(Sci. Eng. Res. Lab. , Waseda Univ.)
FLOCARD Hubert(Inst. Phys. Nucl., Orsay, France)
FUCHI Yoshihide ~1 ~f ~ (Inst. Nucl. Study, Univ . Tokyo)
FUJIOKA Manabu iiiltfiJ $(Dept. Phys. , Tohoku Univ.)
FUKUDA Mitsunori m B3 7't JIIfii (Fac. Sci. , Osaka Univ.)
FUKUDA Tomokazu W; B3 ~.tO (Inst. Nucl. Study, Univ. Tokyo)
GONO Yasuyuki ~ Jll tttf Z(Dept. Phys., Kyushu Univ.)
GUY Y. Bizard(CAEN Univ. , France)
HASEGAWA Takeo ft:fr)I/itx (Fac. Eng. , Miyazaki Univ.)
HASHIZUME Akira ~ J1\ f!J1 (Japan Atomic Energy Relations Organ.)
HITACHI Akira J3 l±. ::!l (Kochi Med. Sch.)it (ColI. Arts Sci., Univ. Tokyo)
ICHIMURA Munetake m ~1
IEKI Kazuo *;tJiX.tO X (Fac. Sci. , Rikkyo Univ.)
IJIRI Kenichim.. ]! - (Radioisot. Cent. , Univ. Tokyo)
ISHIDA Nobumichi :fj B3 i$:ii (Seikei Univ.)
ISHIKAWA Masanobu :fj )1/ ~ *,c. (Tokyo Univ. Fisheries)
IWASAKI Hiroyuki :fi ~ t.w: 11" (KEK)
KANEYUKI Kenji 1t 11" f,t?El (Fac. Sci. , Tokyo Inst. Technol.)
KASAGI Jirohta ~**.e~* (Lab. Nucl. Sci., Tohoku Univ.)
KASAl Kiyomi ~ 1t rff ~ (Natl. Inst. Radiol. Sci.)
KATAYAMA Ichiro h LlJ -.e~ (Inst. Nucl. Study, Univ. Tokyo)
KATO Seigo 1m iii rff ~ (Fac. Educ. , Yamagata Univ.)
KATORI Kenji H!
~(Fac. Sci., Osaka Univ.)
KAWAKAMI Hirokane )1/ 1::
1t (Inst. Nucl. Study, Univ . Tokyo)
KAWASHIMA Hideo )11 ~ ~ if[ (Inst. Nucl. Study, Univ . Tokyo)
KIKUCHI Jun *J H!!. JIIfii (Sci. Eng. Res. Lab. , Waseda Univ.)

*

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KIM Hee J.
(Oak Ridge Natl. Lab., U.S .A.)
KIM Jong Chan ~ jj It (Seoul Natl. Univ., Korea)
KITAHARA Yoshitaka ~t ffit ~ q: (Hoya Corp.)
KITAO Kensuke %$~lM.M (Natl. Inst. Radiol. Sci.)
KOMAGATA Kazuyuki fnJ ~ fO 1T (Asahi Glass Co., Ltd.)KONDO Takahiko :iliiHitlt"i!l (KEK)KUBONO Shigeru 7-.f:*dff ~ (Inst. Nucl. Study, Univ. Tokyo)
KUBOTA Shinzou ~ rn ffi':::' (Fac. Sci., Rikkyo Univ.)
KUSAKARI Hideshige 11- XIJ ~ ~ (Fac. Educ., Chiba Univ.)
LEE Sang Mu*13 ~ (Inst. Phys., Univ. Tsukuba)
LIU Guanhua ;IJ ~.. (Inst. Mod. Phys., Acad. Sinica, China)
MAEDA Kazushige WI 83 fO Lt (CoIl. Gen. Educ., Tohoku Univ.)
MASUDA Kimiaki ~ rn ~ fI}J (Saitama ColI. Health)
MATSUDA Takeshi ;f1} EE ~ (KEK)
MATSUYANAGI Kenichi ;f1} {PP ;pJf (Dept. Phys., Kyoto Univ.)
MIN Byung Joo F:£j p:;j ~ (Korea At. Energy Res. Inst., Korea)
MITARAI Shiro ~~Hti0.M (Dept. Phys., Kyushu Univ.)
MIYACHI Takashi g:t-t!! q: (Inst. Nucl. Study, Univ. Tokyo)
MIYATAKE Hironari g ~ ~ -tf! (ColI. Gen. Educ., Osaka Univ.)
MORINOBU Shunpei ~ ffi f~ lJZ (Dept. Phys., Kyushu Univ.)~(Fac. Sci., Rikkyo Univ.)
MOTOBAYASHI Tohru
MOTTELSON Ben R.
(NORDITA, Denmark)
MUKERJEE Reshmi(Columbia Univ., U.S.A.)
MURAKAMI Takeshi ff 1: 11: (Natl. Inst. Radiol. Sci.)
NAGAI Yasuki 7k~ W (Fac. Sci., Tokyo Inst. Technol.)NAGASHIMA Yasuo~ ~ ~(Dept. Phys. , Univ. Tsukuba)
NAKAJIMA Mitsuo ~ ~ 7E ~ (Graduate Sch. Nagatsuda, Tokyo Inst. Technol.)
NAKAMURA Syougo q:t ff JE ~ (Fac. Educ., Yokohama Natl. Univ.)
NAKAYAMA Shintaro q:t wffi*.M (ColI. Gen. Educ., Tokushima Univ.)
NEUGART Rainer(Mainz Univ., Germany)
NIIZEKI Takashi ~fi ~ ~ (Fac. Sci., Tokyo Inst. Technol.)
NORO Tetsuo ff g fg ~ (RCNP, Osaka Univ.)
OGAWA Masao /J~ )11 ff ~ (Graduate Sch. Nagatsuda, Tokyo Inst. Technol.)
OGURA Koichi /J~ i" ff.ti. (ColI. Ind. Technol., Nihon Univ.)
OHNUMA HajimefB(Fac. Sci., Tokyo Inst. Technol.)
OKAMURA Hiroyuki [00] ff 5.L. Z(Fac. Sci., Univ. Tokyo)
ORIHARA Hikonojo *lffitffiz?[s (Cyclotron Radioisot. Cent., Tohoku Univ.)
OSHIMA Masumi~ it ~~(Japan Atomic Energy Res. Inst.)
OSHIRO Takashi ~ ~ ~ (Tokyo U niv. Fisheries)
OTSUKA Takaharu
q: tEl (Fac. Sci., Univ. Tokyo)
OYAIZU Michihiro /J~{PP~$7EJ.b: (Inst. Nucl. Study, Univ. Tokyo)
RUAN (GEN) Jianzhi jSjG ~ tEl (Dept. Phys., Rikkyo Univ.)
SAKAGUCHI Harutaka :I:)j 0 tEl ~ (Dept. Phys., Kyoto Univ.)
SAKAI Mitsuo #x
J't ~ (Inst. Nucl. Study, Univ. Tokyo)
SAKAI Yoshihide ±W
~ ~
(KEK)
~L. Z
(Fac. Sci., Osaka City Univ.)
SAKURAGI Hiroyuki t~
SAKURAI Hiroyoshi t~
tf ~ (Fac. Sci., Univ. Tokyo)
SATO Hiroshi 1~ il Wi: (Seikei Univ.)
SCARLASSARA Fernando(Univ. di Padova, Italy)
SHIBAMURA Eido ~ ff
(Saitama ColI. Health)
SHIMIZU Hajime ~ 7jc ~ (Fac. Educ., Yamagata Univ.)
SHIMIZU Yoshifumi m 7jc ~ X (Dept. Phys., Kyushu Univ.)
SHIMODA Tadashi ~ rn JE (ColI. Gen. Educ., Osaka Univ.)
SHIMOURA Susumu T Hti ¥(Dept. Phys., Rikkyo Univ.)
SHIRATO Shoji B ± w}
(Dept. Phys., Rikkyo Univ.)
SHIROYAMA Masaki ~ W JE W (Asahi Glass Co., Ltd.)SUEKANE Fumihiko--er X ffi (Fac. Sci., Tohoku Univ.)
SUGAWARA Masahiko 'if ffit l§ 1$ (Chiba Inst. Technol.)

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SUZUKI Yasuyuki ~ft
A L (Dept. Phys. , Niigata Univ.)(Natl. Inst. Radiol. Sci.)
TAKADA Eiichi r-'e1 m 5R lM. 1'I}j (CoIl. Gen. Educ., Osaka Univ.)
TAKAHASHI Noriaki r-'e1
TAKAHASHI Tadayuki r-'e1 m ,r~, ¥(Fac. Sci. , U niv. Tokyo)
TAKAKU Shinsaku r-'e1!A.. m- f'F (Inst. Nucl. Study, Univ. Tokyo)
TAKIGAWA Noboru ii!)1[ ~ (Dept. Phys., Tohoku Univ.)
q:t ft ffi (Inst. Nucl. Study, Univ. Tokyo)
TANAKA Masahiko
TANIMORI Tohru :e:. ~ Jt (Fac. Sci., Tokyo Inst. Technol.)
TANOKURA Atsushi E8ff~ f~ (Fac. Sci. Technol., Sophia Univ.)(Radioisot. Cent. , Univ. Tokyo)
TAO Kazuyuki :tt to L
TERAKAWA Atsuki ~ )I[ ..
(Cyclotron Radioisot. Cent., Tohoku Univ.)
TLUSTY Pavel(Inst. Nucl. Study, Univ. Tokyo)
TOKI Hiroshi ± ~~ t2j: (Dept. Phys., Tokyo Metrop. Univ.)
TOYOKAWA Hidenori ~ )I[ Jf; IDI\ (RCNP, Osaka Univ.)
UNNO Yoshinobu i4lj ff • 18 (KEK)UNO Masahiro
ff iE(The Ministry of Education)
WATANABE Yasushi V!l J2l ~ i0 (Fac. Sci. , Tokyo Inst. Technol.)f1i ~ (Fac. Sci. TechnoI. , Sophia Univ.)
YAMAMOTO Sukeyasu tlJ
YAMAYA Takashi tlJ ~ 3t (Dept. Phys. , Tohoku Univ.)
Ill. ts (Kagoshima Agr. Exp. Stn.)
YATO Osamu
YOSHIDA Kazuo
E8 to X (Hoya Corp.)
YOSHINAGA Naotaka
7k fl;j:4 (Saitama Univ .)YOSOI Masaru JIF!~* 11 (Dept. Phys. , Kyoto Univ.)it (Fac. Sci. , Tohoku Univ.)
YUTA Haruo i~ E8
ZHANG Yuhu ~ .:li J1E (lnst. Mod. Phys. , Acad. Sinica. , China)

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AKEBOSHI Yoshihiro Il}j £ tf ~f (Fac. Sci. , Tokyo lnst. Technol.)
AOI Nori w:1t ~ (Fac. Sci. , Univ. Tokyo)
CHAE Soo-Joh(Seoul Natl. Univ., Korea)
DOl Masashi ±ft ~ (Fac. Sci. , Tokyo Inst. Technol.)
DOKI Yasuhiro ± ~e 1ft t-f (Fac. Sci. , Univ. Tokyo)
FUJITA Tetsushi Jii E8 rg: ~ (Fac. Sci. , Univ. Tokyo)
FURUTAKA Kazuyoshi I:!l r-'e1 to t~ (Fac. Sci., Tokyo Inst. Technol.)
FUTAMI Yasuyuki
Jf. ~ Z (Inst. Phys., Univ. Tsukuba)
GUIMARAES Valdir(Inst. Nucl. Study, Univ. Tokyo)
HANAKI Hidenobu 1EJf; 18 (Fac. Sci. , Tokyo Inst. Technol.)
HARA Yousuke 1* ~f 1r- (Fac. Sci. , Tokyo Inst. Technol.)
HARADA Masaki 1* E8 l§(Fac. Sci., Tokyo Inst. Technol.)
HASUIKE Katsuhito ~ ~ Jm A (Sch. Sci. Eng. , Waseda Univ.)
HIRAI Masaaki 1fl
iE Il}j (Fac. Sci. , Univ. Tokyo)
HONJO Yoshio~
X (Inst. Phys., Univ. Tsukuba)
HORI Yoichi f)ffi~~ (Fac. Sci., Tokyo Inst. Technol.)
HOSAKA Masahito f* ~ ~~ A (Cyclotron Radioisot. Cent., Tohoku Univ.)
ICHIGE Masayuki m.f; iE L
(Sch. Sci. Eng. , Waseda Univ.)
IDEGUCHI Eiji :1t-¥ lJ5RtS (Dept. Phys., Kyushu Univ.)
IKEDA Yasufumi ~ E8 ~ X (Dept. Phys., Rikkyo Univ.)
INOUE Masahiro
J::. l§(Dept. Phys. , Rikkyo Univ.)
ISHIDA Satoru ~ B3 'I~ (Fac. Sci. , Univ. Tokyo)
ITO Tomoyuki 1¥ Jii M 1T (Sci. Eng. Res. Lab., Waseda Univ.)(Dept. Phys., Rikkyo Univ.)
IWASA Naohito ;fi it. il t
(Dept. Phys. , Rikkyo Univ.)
IWATA Yoshiyuki ;fi B3 it L
IZUMI Hideaki lli 7./'< Jf; 1'I}j (Fac. Sci., Tokyo Inst. Technol.)
KAMIMURA Kazuto J::.;t;j" to A (Dept. Phys. , Rikkyo Univ.)
KATOH Kenichi 111l Jii 1M! (Fac. Sci., Tokyo Inst. Technol.)~(Dept. Phys., Rikkyo Univ.)
KAWAGUCHI Tsutomu )I[ IJ
KIDERA Masanori~ iE lM.
(Dept. Phys., Kyushu Univ.)
KIKUCHI Tadashi *1:till JE (Dept. Phys. , Rikkyo Univ.)

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198

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KOBAYASHI Misaki /J\ l* ~(Sch. Sci. Eng., Waseda Univ.)
KOBINATA Hideo /J\ B rDJ~x (Fac. Sci., Univ. Tokyo)
KOGANEMARU Kenichi /J\~}l:tt~ (Graduate Sch. Nagatsuda, Tokyo Inst. Techno!.)KOMIYAMA Tatsuto -i6 W iL A (Sch. Sci. Eng., Waseda Univ.)
KUBO Madoka !A. 1* Pi (Fac. Sci. Technol., Sophia Univ.)
KUROKAWA Meiko ~ )1/ I'IjJ -i- (Dept. Phys., Rikkyo Univ.)
KUWAHARA Kota ~ rni(Sch. Sci. Eng., Waseda Univ.)
EB~(Fac. Sci., Tokyo Inst. Technol.)
MATSUDA Kiyohide(Fac. Sci., Univ. Tokyo)
MATSUZAKI Keiichi ;fJ} ~ ~ MIYAMOTO Shouichi gag ~ (Cyclotron and Radioisot. Cent. , Tohoku Univ.)~~(ColI. Gen. Educ., Osaka Univ.)
MIZOI Yutaka ~MOCHINAGA Kensuke f;=f 71< ~ fr (Fac. Sci., Univ. Tokyo)
MORIYA Shingo ;:j= ffi J{.g (Dept. Phys., Rikkyo Univ.)
MURATA Tomoki ft EB ~O l1t (Fac. Sci. Technol. , Sophia Univ.)
NAGANUMA Masayuki 71< m iE iT (Graduate Sch. Nagatsuda, Tokyo Inst. Technol.)
NAGATA Kazuhiko :Ii EB fD ffi (Fac. Sci., Tokyo Inst. Technol.)
NAKAMURA Tadashi 9=t ft iE (Sci. Eng. Res. Lab. , Waseda Univ.)
NISHIO Teiji g§ If; t~?E (Dept. Phys. , Rikkyo Univ.)
NUNOYA Yoshihiko ;ffi ~ g ffi (Dept. Phys., Rikkyo Univ .)ODAHARA Atsuko /J\EBrniW-i- (Dept. Phys. , Kyushu Univ.)
OGAMI Hiroshi If; 1: tf Ii] (Fac. Sci. , Tokyo Inst. Technol.)
OGAWA Hiroshi /J\ )11 tf""PJ (Fac. Sci. , Tokyo Inst. Technol.)
OGAWA Shinsuke /J\ )1/ 1{ ~ (Dept. Phys., Rikkyo Univ.)g§ rfi. -T(Coli. Agric. Vet. Med., Nihon Univ.)
OHNISHI Hiroko
OHSAKI Yoshinori% ~ *,C (Graduate Sch. Nagatsuda, Tokyo Inst. Techno!.)Z (Sch. Sci. Eng., Waseda Univ.)
OKADA Hiroyuki lRiJ EB
OKUNO Hiroki ~ ff fA l1t (Fac. Sci. , Univ. Tokyo)
OTSU Hideaki "*~! ~ B)t (Fac. Sci. , Univ. Tokyo)
SAITO Tomoki
Jfi ~O l1t (Seikei Univ.)
SAITO Yoshitaka ~ Jfi 7f ~ (Fac. Sci., Univ. Tokyo)
SAKAMOTO Naruhiko :I:JX
JJX ffi (Fac. Sci., Univ. Tokyo)
SASAKI Mitsuru ftrJ<* 1f.. (ColI. Gen. Educ., Osaka Univ.)
SATO Hiromi f~ Jfi fA ii (Fac. Sci., Tokyo Inst. Technol.)
SATO Hiroyasu f~ Jfi 51.. fflt (Seikei Univ.)
SATOU Yoshiteru f~ Jfi ~ Jr! (Fac. Sci. , Univ. Tokyo)
SAWADA Shinya ~~ EB J{ -ttl (Dept. Phys., Kyoto Univ.)
SEKINE Takashi ~ tH ~i: (Fac. Sci., Tokyo Inst. Technol.)
SHIBATA Masataka ~ EB Jft ~i: (Dept. Phys. , Kyushu Univ.)
SHINODA Morihiko r~ EB ;:j= ffi (Sci. Eng. Res. Lab. , Waseda Univ .)iE i0 (Dept. Phys. , Rikkyo Univ.)
SHIRAKI Tadashi B
SHIRAKURA Tetsuya B ~ W -t:!! (ColI. Gen. Educ. , Osaka Univ.)
SHIMURA Masakatsu i0 ft iE 1m (Fac. Sci . Technol., Sophia Univ.)
SHIZUMA Toshiyuki ~ rl3' {~iT (Dept. Phys. , Kyushu Univ.)~ iT(Dept. Phys. , Kyushu Univ.)
SUEMATSU Shigeyuki~1f ~1lJ(Fac. Sci., Univ. Tokyo)
SUZUKI Kiyoshi ~~TAJIMA Yasuhisa EB ~ ~!A. (Fac. Sci. , Tokyo Inst. Technol.)
TAKEDA Kenji it EB It i0 (Fac. Sci. , Tokyo Inst. Technol.)
TERANISHI Takashi =!f g§~(Fac. Sci., Univ. Tokyo)
TOMITA Shigeo ~ EB JJX X (Inst. Phys. , Univ. Tsukuba)
TOMURA Hiromi ji.. ft ~~ ~ (Dept. Phys., Kyushu Univ.)
TUCHIDA Hideo ± EB
X (Fac. Sci., Tokyo Inst. Technol.)
UCHIBORI Takeshi IAJ j;jffi ~ Ii] (Fac. Sci. Technol. , Sophia Univ.)
UENO Hideki 1: ff ~ W (Fac. Sci., Tokyo Inst. Technol.)
UESAKA Tomohiro 1: jJj 1X~:F (Fac. Sci., Univ. Tokyo)
WAKASA Tomotsugu :ff ~ ~""PI (Fac. Sci., Univ. Tokyo)(Fac. Sci., Univ. Tokyo)
WATANABE Yutaka lIt Jll
YAMAMOTO Takuhisa W ~!A. (Fac. Sci., Tokyo Inst. Technol.)
YAMASHITA Toshiyuki W T flJ $- (Fac. Sci., Tokyo Inst. Technol.)

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YAMAZAKI Hiroshi tlJ ~ 5.L. ~Il) (Fac. Sci., Tokyo Inst. Technol.)
YANAGISAWA Yoshiyuki ~p ~~ % 11- (Dept. Phys., Rikkyo Univ.)
YOON Chong Cheol ~ ~ ~ (Fac. Sci., Tokyo Inst. Technol.)Atomic Physics Laboratory
ANDO Kozo 1i. Hi Il'JIJ
KAMBARA Tadashi t$
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KRAVIS Scott(STA-fellow)
NISHIDA Masami ~ EEl W ~SHIMAMURA Isao ~ tt '-k**
WATANABE Naoki i1t $

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AWAYA Yohko ~ ~ ~ -f-*
KANAI Yasuyuki ~1* L
NAKAI Yoichi I:J:l~£ OURA Masaki
iii JETAN G J ianzhi Jlf J(!;0YOSHIDA Takashi is EEl ~ ;0

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AZUMA Toshiyuki{~11(ColI. Arts Sci., Univ. Tokyo)
DANJO Atsunori 11 1: ~ 1!@ (Dept. Phys., Niigata Univ.)(Kansas State Univ., U.S.A.)
DEPAOLA Brett D.
FUJIMA Kazumi Hi ra' - ~ (Fac. Eng. , Yamanashi Univ.)
FUKUDA Hiroshi W; EEl(Sch. Administration and Informatics, Univ. Shizuoka)
HARA Shunsuke 1* {~ft"- (Dept. Gen. Educ. , Tsukuba ColI. Technol.)
HARSTON Michael R.
(Dept. Math., Univ. Nottingham, U.K.)(Dept. Appl. Phys. Chern., Univ. Electro-Commun.)
HINO Kenichi 8 If 1m HITACHI Akira ~ tf:'. jfi: (Sci. Eng. Res. Lab. , Waseda Univ.)
HUTTON Roger(Univ. Lund, Sweden)
ISHII Keishi ;;S1l L (Dept. Eng. Sci. , Kyoto Univ.)
ISOZUMI Yasuhito li +~~A (Inst. Chern. Res., Kyoto Univ.)
ITO Shin W Hi J{. (Radioisot. Res. Cent. , Kyoto Univ.)
ITOH Akio W Hi f}( ~ (Fac. Eng., Kyoto Univ.)
ITOH Yoh W Hi ~£ (Fac. Sci. , Josai Univ.)
KARASHIMA Shosuke J!- ~ .~~ ft"- (Dept. Electron. Eng., Tokyo Univ. Sci.)
KAWATSURA Kiyoshi }I/ 00 af (Kyoto Inst. Technol.)
KIMURA Mineo
tt ~ 1:: (Argonne Natl. Lab. , U.S.A.)
1§ X (Dept. Phys., Tokyo Metrop. Univ.)
KOBAYASHI Nobuo IJ\
KOHARA Takao IJ\
4 X (Fac. Sci. , Himeji Inst. Technol.)
KOIKE Fumihiro Ij\ H!~ :>c tf (Sch. Med., Kitasato Univ.)
KOIZUMI Tetsuo Ij\ 7'R ~ X (Dept. Phys. , Rikkyo Univ.)
KOMAKI Kenichiro Ij\4x1iJf-.M (ColI. Arts Sci. , Univ. Tokyo)
KOWARI Kenichi IJ\ ~Ij 11: (Dept. Chern., Tokyo Inst. Technol.)
KUROKI Kenro ~1m.M (Natl. Res. Inst. Police Sci.)
MARTINSON Indrek(Univ. Lund, Sweden)(Dept. Pathol. , Tokyo Med. Dent. Univ.)
MATSUO Takashi ~ ~MATSUZAWA Michio ~ i~ im ~ (Dept. Appl. Phys. Chern. , Univ. Electro-Commun.)EElt-t 11fl (Fac. Eng., Himeji Inst. Technol.)
MITAMURA Tohru
MIZOGAWA Tatsumi ~ }I/ ~ E (Nagaoka ColI. Technol.)MUKOYAMA Takeshi IoJ tlJ ~~ (Inst. Chern. Res. , Kyoto Univ.)
NYSTROEM Bosse(Univ. Lund , Sweden)~ {~ft"(Inst. Laser Sci. , Univ. Electro-Commun.)
OHTANI Shunsuke
OKUNO Kazuhiko ~ If ~D ~ (Dept. Phys. , Tokyo Metrop. Univ.)
O'ROURKE Franceska(Dept. Appl. Math., Queen's Univ. Belfast, U.K.)(Dept. Phys. , Ochanomizu Univ.)
SATO Hiroshi itt. Hi Hi
SCHMIDT-BOCKING Horst(Univ. Frankfurt, Germany)
SEKIOKA Tsuguhisa ~ /iU] rlUPJ ~ (Fac. Eng. , Himeji Inst. Technol.)~(Res. Cent. Nucl. Sci. , Univ. Tokyo)
SHIBATA Hiromi ~ EEl
tf (Tandem Accel. Cent., Univ. Tsukuba)
SHIMA Kunihiro ~SHIMAKURA Noriyuki ~ ~ *c. L(ColI. Gen. Educ. , Niigata Univ.)
SPIELBERGER Lutz
(Univ. Frankfurt, Germany)

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SUGER Jack
(Natl. Inst. Stand. Technol., U.S.A.)SUZUKI Hirosi ~it~$(Inst. Laser Sci., Univ. Electro-Commun.)
TAKAYANAGI Toshinobu rWJ.fPp 13t ~ (Dept. Phys., Sophia Univ.)
TAWARA Hiroyuki {£{ t.w: Z (N at I. Inst. Fusion Sci.)TERASAWA Mititaka ~~" flfii q: (Fac. Eng., Himeji Inst. Technol.)TOSHIMA Nobuyuki F JiJ.~ 1§" ¥(Inst. Appl. Phys. , Univ. Tsukuba)
TSURUBUCHI Seiji t~ iJ#! ~(Fac. Technol., Tokyo Univ. Agric. Technol.)
WAKIYA Kazuyoshi Jla:§. - ~ (Dept. Phys. , Sophia Univ.)(Dept. Appl. Phys. Chern., Univ. Electro-Commun.)
WATANABE Shinichi iJ.l ill
YAMAZAKI Yasunori LlJ Ilffifm (ColI. Arts Sci., Univ. Tokyo)
YOSHINO Masuhiro 6 ff ~"5.L. (Lab. Phys., Shibaura Inst. Technol.)(Inst. Phys. Nucl. Eng., Romania)
ZORAN 1. Valeriu
ZOU Yarning ~~ iJE aJJ (Jiao Tong Univ., China)

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KAKUTANI Nobukazu ~:§. ~ KASUGA Masahito ~ B .. A (ColI. Arts Sci., Univ. Tokyo)
KOIDE Michi IJ\ lli ~ ~ (Dept. Phys., Meisei Univ.)
KYOH Suigen~rjJ ~(Fac. Eng., Kyoto Univ.)
NAKAMURA Nobuyuki 9=t1§" iT (Inst. Laser Sci., Univ. Electro-Commun.)
NEGISHI Tomoo tH i¥ ~ ~ (Dept. Phys., Sophia Univ.)
SANO Mutsumi ftc ff om (Dept. Phys., Rikkyo Univ.)
YAMAGATA Masahiro LlJ *~ l§ r.t. (ColI. Arts Sci. , Univ. Tokyo)
YAMASHITA Tetsurou LlJ r 11i!L .M (Dept. Phys., Rikkyo Univ.)**1'

Metal Physics Laboratory
ISHIDA Katsuhiko ;S B3 MJ -g.
KINO Yasushi
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MATSUNO Shunichi ~ ff 13t NAG AMINE Kanetada 71< ~ ~ ,"t,*YAGI Eiichi j\
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KADONO Ryosuke r~ ff ~ ~KOYAMA Akio IJ\ LlJ a~ iit
MATSUZAKI Teiichiro ~1Ii~HJnn.M
WATAN ABE Isao iJ.l it :fj] iit** Senior Scientist(Visitors)
AKAISHI Yoshinori :;ffi;S ~ *c. (Fac. Sci. , Hokkaido Univ.)
FUJIOKA Manabu ii Ita] ~ (Cyclotron Radioisot. Cent., Tohoku Univ.)
JONES E. Steven(Dept. Phys. Astronomy, Brigham Young Univ., U.S.A.)
KAMIMURA Masayasu L.IE ~ (Fac. Sci., Kyushu Univ.)
KUMAGAI Kenichi ft~:§. '0! (Fac. Sci., Hokkaido Univ.)aJJ (Res. Dev. Co. Ltd. , Japan)
MATSUSHITA Akira ~ r
MINAMISONO Tadanori i¥i III ,"t, DO (Fac. Sci., Osaka Univ.)
MIYAKE Yasuhiro .:::. ~ ~ t~ (Meson Sci. Lab., Univ. Tokyo)
MORITA Masato ~ EE if. A (Fac. Sci. , Josai Univ.)
TORIKAI Eiko ,~. Me -f- (Fac. Eng., Yamanashi Univ.)
WATANABE Tsutomu ill:g:~ fJ (ICU)*1'(Students)
DAWSON Wayne(Fac. Sci., Univ. Tokyo)
STRASSER Partrick(Fac. Eng., Univ. Tokyo)

Magnetic Materials Laboratory
OKADA Takuya IMJ B3 !j! -m **** Senior Scientist

201

Plasma Physics Laboratory
OYAMA Hitoshi
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SAKAMOTO Yuichi:iJj

YANO Katsuki* lit -

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Microwave Physics Laboratory
MIN 0 H Arimichi ~ Btl tE il!

Earth Sciences Laboratory
TAKEMATSU Noburu tt ~1$

Inorganic Chemical Physics Laboratory
AMBE Shizuko 17: *~ M .:;.
MATSUO Yukari ~~EB~fIJ

MAEDA Kuniko
TAKAMI Michio

WJ m j:j) .:;.
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ISHII Keizo
KAWAI Jun:£1tJit€
iliJ -€i- iM(Cyclotron Radioisot. Cent., Tohoku Univ.)(Dept. Metallurgy, Kyoto Univ.)

Nuclear Chemistry Laboratory
AMBE Fumitoshi 17: *~
fff:t*ITOH Yoshiko 1ft)/( 7f
KOBAYASHI Yoshio IJ\ ~*~OHKUBO Yoshitaka *~1*~rWJ

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ASAI Kichizo ~~ 1t Ef Ji§. (U niv. Electro-Commun.)
BABA Hiroshi ,~j:£ 1.i (Fac. Sci., Osaka Univ.)
CHEN Shaoyong !it *B ~ (South China Sea Inst. Oceanol.)
ENDO Kazutoyo :ii Hi fD ~ (Showa ColI. Pharm. Sci.)FURUKAWA Michiaki tr )11 ~ aJ} (Fac. Sci., Nagoya Univ.)
jj[: (ColI. Sci. Eng., Aoyamagakuin Univ.)
HARAKAWA Hiroaki 1* )11
HIRUNUMA Rieko !I!~mfIJ~I':;' (Showa ColI. Pharm. Sci.)
ITO Yasuo W Jii.
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(Res. Cent. Nucl. Sci. Technol., Univ. Tokyo)(Fac. Educ., Gakugei Univ.)
KANAZAWA Ikuzo 16: if{ W~t~~(ColI. Sci. Eng., Aoyamagakuin Univ.)
KIMURA Kan
Z (Sch. Hygien. Sci., Kitasato Univ.)
KOBAYASHI Takayuki IJ\ ~*KOJIMA Sadao IJ\ 8b ft ~ (Nucl. Med. Cent., Aichi Medical Univ.)
MINAI Yoshitaka ~ ~ 1:1 q: (Fac. Sci., Univ. Tokyo)
MURAKAMI Hideoki ~t 1: ~ J! (Tokyo Gakugei Univ.)
NOZAKI Tadashi ff rIffif iE (Sch. Hygien. Sci., Kitasato Univ.)
OKADA Shigenobu IRiJ
~ ffi
(RID Eng., Shimazu Corp.)
SAITO Kazuo :g Jii. fD ~ (Toshiba Corp., R&D Cent.)
SAITO Tadashi ~ iii Il (Fac. Sci., Osaka Univ.)
SHIBATA Sadao ~ m ~ X (Natl. Inst. Radiol. Sci.)SHIBATA Seiichi ~ m ~ (Inst. Nucl. Study, Univ. Tokyo)
If- (Fac. Sci., Nagoya Univ.)
SHINOHARA Atsushi 1fi
SUGAllsao -g 1t Jim (Inst. Nucl. Study, Univ. Tokyo)
jj[: (Showa ColI. Pharm. Sci.)
TANAKA Akira m I=j:t

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TAZAKI Kazue E8 ~ fD ~I (Fac. Sci., Shimane Univ.)
TOMINAGA Takeshi ~ 7]< f,f: (Fac. Sci., Univ. Tokyo)
l& ~t (JAERI, Tokai)
YAlTA Tsuyoshi
7]< IDOC A(Jikei Univ. Sch. Med.)YANAGA Makoto
YOKOTA Yuko ;nt E8-f- (ColI. Sci. Eng., Aoyamagakuin Univ.)
YOKOYAMA Akihiko ;nt LlJ flf! ~ (Fac. Sci., Osaka Univ.)
YUKAWA Masae i~)I[ ~ lx (Natl. Inst. Radiol. Sci.)

**

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(Students)
J'5j tt-t (ColI. Sci. Eng., Aoyamagakuin Univ.)
AOKI Naoki W
BAMBA Takehiro ~!~ 5:: t.w: (ColI. Sci. Eng. , Aoyamagakuin Univ.)
FURUTA Riko it E8 l![ -f- (Showa ColI. Pharm. Sci.)
E8 tf P] (Showa CoH. Pharm. Sci.)
HARUTA Hiroshi
KASUGA Ryouichi
B li! (Fac. Sci., Osaka Univ.)
KIRIU Masaru $lJ 1:(Fac. Sci., Osaka Univ.)
KURACHI Junji ~ *0 ~l ~ (Fac. Sci., Nagoya Univ.)
MUKAI Kazuhiko rOJ fD ~ (Fac. Sci., Osaka Univ.)
MUROYAMA Toshiharu ~ LlJ 1~ ~11i (Fac. Sci., Nagoya Univ.)
NAKAMURA Jin ~:ft t(Univ. Electro-Commun.)(Fac. Sci. , Nagoya Univ.)ODA Hirotaka /J\ E8 J( "OHTSUKA Hiroshi
t.w: ~ (Fac. Sci. , Univ. Tokyo)
OTA Tomoko :* E8 ffi -f- (Fac. Sci., Univ. Tokyo)
SATO Yoshihiko itr. Wi ~ ~ (Fac. Sci., Nagoya Univ.)
TAKAHASHI Yoshio rWJ tl ~ X (Fac. Sci., Univ. Tokyo)
TAKESAKO Kazuhiro 1t J§. fD ~11i (Fac. Sci., Osaka Univ.)
TAKESHITA Kazutaka 1t P fD ~ (Fac. Sci., Toho Univ.)~(Fac. Sci. , Toho Univ.)
TANAKA Shigeo E8 J:j:l(Fac. Sci., Nagoya Univ.)
TANIGUCHI Eugene :a. IJ ~ t
WATANABE Seiya ~~ ill IDOC ill (Fac. Sci., Osaka Univ.)
YAMAGUCHI Takayuki LlJ IJ .. 1T (Fac. Sci., Osaka Univ.)fF (Fac. Sci., Osaka Univ.)
YANO Daisaku

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Chemical Dynamics Laboratory
KIMURA Kazuie *:ft - ~(Visitors)
ITO Yasuoi¥ Wi ~ ~(Res. Cent. Nucl. Sci. Technol. , Univ. Tokyo)(Students)
SAHARA Yasumori itr. 1m 9I!f ~ (Dept. Phys. , Chuo Univ.)
SHIBA Takayuki ~ .. Z
(Dept. Phys., Chuo Univ.)
YOKOO Keiichi ;nt ~ rg: (Dept. Phys., Chuo Univ.)

Cellular Physiology Laboratory
HANAOKA Fumio 1E [Iil] :>c tl*
YATAGAI Fumio :a.E8Jt:>Cx**KITAYAMA Shigeru~t LlJ~~* Chief Scientist, ** Senior Scientist(Visitors)
ANDO Koichi ~ Wi J!. (N at!. Inst. Radiol. Sci.)
FUKUMURA Akifumi W;:ft flf! ~ (Natl. Inst. Radiol. Sci.)
FURUSAWA Yoshiya it i,R. it ill (Natl. Inst. Radiol. Sci.)
HASHIMOTO Shozo tl
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HOSHINO Kazuo
tl (Natl. Inst. Radio!' Sci.)IIZUKA Masayuki jj ±j( JE;;t (Natl. Inst. Radiol. Sci.)

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ITO Hisao 1ft
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ITOH Hiroko 1ft Jfi ~.:-;- (Natl. Inst. Radiol. Sci.)
ITSUKAICHI Hiromi .liB mlf~h (Natl. Inst. Radiol. Sci.)
KANAI Tatsuaki ~:it 1'1)1 (Natl. Inst. Radiol. Sci.)
KAWACHI Kiyomitsu iPJ pq m-:J't (Nat!. Inst. Radiol. Sci.)
KIKUCHI Masahiro *J jiB .IE tf (JAERI, Takasaki)
KHJOTO Masafumi
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KOBAYASHI Yasuhiko /J\ ~* ~ ffi (JAERI, Takasaki)
KOHNO Toshiyuki filJ!f {~z. (Natl. Inst. Radiol. Sci.)
KOIKE Sachiko /J\ i-t!!. ¥ -T (Natl. Inst. Radiol. Sci.)
KOJIMA Eiichi /J\ ~ 5R (Natl. Inst. Radiol. Sci.)
KOSAKA Toshifumi /J\:l:R {~)( (Dept. Vet. Radiol. , Nihon Univ.)
KUBOTA Nobuo ~ B3 :it:x (Fac. Med. , Yokohama City Univ.)
McINTYRE Cindy L.
(Radiobiol. Unit, Med. Res. Counc. , U.K.)
MINOHARA Shinichi fl ffit
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MURAISO Chidori ~1li!l ~(Natl. Inst. Radiol. Sci.)
MURAKAMI Masahiro ~1..t.IE ilL. (Natl. Inst. Radiol. Sci.)
NAKAI Hirokazu q:tilL. fD (Dept. Agric., Shizuoka Univ.)
ffit 5.L. (Dept. Gen. Cult. , Okayama Univ.)
OHARA Hiroshi
OKUMURA Toshiyuki ~ ~1 fit(Fac. Med. , Univ. T sukuba)(Inst. Nucl. Study, Univ. Tokyo)
SOGA Fuminori ~:fX)( g
SUDO Michio ~~Jfi~~tl (Natl. Inst. Radiol. Sci.)TAGUCHI Yasuko IE IJ ~ --1- (Natl. Inst. Radiol. Sci.)
TAKATUJI Toshihiro rWJ j± {~* (RI Cent. , Nagasaki Univ.)
TANAKA Kaoru IE q:t •(Natl. Inst. Radiol. Sci.)TATSUZAKI Hideo ft ~ ~:X (Fac. Med., Univ. Tsukuba)
TOMURA Hiromi 71- ~1 ?* ~ (Natl. Inst. Radiol. Sci.)
TSUBOI Atsushi P¥~(Natl. Inst. Radiol. Sci.)
TSUBOUCHI Susumu P¥- iAJ :at (Suzuka Med. Technol. Univ.)
WATANABE Hiroshi iJt ill.
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WATANABE Masami iJt ill. .IE G (Fac. Pharm. , Nagasaki Univ.)
YAMASHITA Shoji LIJ r l§
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TAKAHASHI Hideyuki rWJ~ ¥(Fac. Med. , Univ. Tsukuba)m

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SUZUKI Masao ~~*(Fac. Med., Tokai Univ.)(Fac. Pharm. , Nagasaki Univ.)*(Students)
KASE Youko

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KUMAGAI Noritaka 1!~:§.;X q:
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HANASAKA Takao l£:I:JX q: it (Shimazu Co.)
HAYAKAWA Shinjiro If.} !I'I:~ = .M (Dept . Ind. Chern. , Univ. Tokyo)
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HIRANO Yoshiki -0/ ff 7f fit (Anelva Co.)INOUE Kouji 1t L ~~ P] (Kobe Steel. Ltd.)(IHI Co.)
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IGARI Sinichi 3~ ~~ J{. (ColI. Hum. Sci. , Nihon Univ.)
KATO Haruhiko 110 iii
ft. (Fac. Eng. Sci. , Chuo Univ.)
SUGANUMA Kenji 1f
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FUJITA Jirou

ANDO Ainosuke ~"*~z'ii
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FURUTAKA Kazuyoshi

ASAI Tatsuo

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FURUYA Keiichi~~~-T

AWAYA Yohko

AZUMA Toshiyuki
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BABA Hiroshi
BAUER W.

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BEHRK. H.

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GAl Moshe
GEISSEL Hans
GOTO Akira

161, 16336

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46
48

BERGSTROM Jr. P. M.

56

111

HACKE Marcus

74

HANAOKA FUmio

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HARA Masahiro
45

BROCKMANN Rolf

HARA Shunsuke

19

52
48

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113
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HARASAWA Kaoru rnt iR 11
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BOYD Richard N.

CHAE Soo Joh

35,36,37,43,119

135, 137, 139

BENENSON W.

BURKARD K.

125

52

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BIZARD Guy

35, 36, 37, 43, 119

43

GONO Yasuyuki
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87,89

32

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GALONSKY Aaron

60

87,88,89

BELBOT Michael D.

CEBRA D.

FUTAMI Yasuyuki

103

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FURUNO Kohei

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131

FUKUDA Shigekazu

FUKUNISHI Nobuhisa

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FUJITA Yoshitaka jj'j.EBtiq:
30
FUJIWARA Shigeki

143

AOI Nori

ARATANI Michi

41

73

FUJIOKA Manabu

77,78, 79,80,81,82,83,~iii&.

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FUJIMAKI Masaki

35, 36, 37

84, 85, 86, 90

ANDO Yoshiaki

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FU JII Satoshi

43~1"tlf~FUCHI Yoshihide

50, 51~:g:B)(fi5cAMBE Shizuko

53,6llJI£.~$AKEBOSHI Yoshihiro
AMBE Fumitoshi

FRANCE Jr. Ralph Hayward42~rnt*'j1t

AIHARA Toshimitsu

31, 32, 33* i*:f'F

HARN Kevin I.

31, 32, 33

43

CHEN Shaoyong

Il* *2 ~77

HARSTON Michael R.

CHIBA Toshiya=p~*'j~5, 137, 139

HASEBE Hiroo

CHIBA Yoshiaki=p~"tlfllJI

5, 13757, 58-ft~$*il

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CHLOUPEK Frank

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CHRISTIE William

34, 44

HASUIKE Katsuhito~i-If1.Mj A

116!tmq:.i§'tfl

39, 40, 130

CRONQVIST M.

48

HATANAKA Kichiji

DELBAR Thierry

43

HAYASHI Katsuyuki
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HEMMI Masatake :i!~ilXJlt
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DEPAOLA Brett

63

DOKE Tadayoshi

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DOKI Yasuhiro
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99, 116HINO Kenichi

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HIRAI Masaaki

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20,21,44

EGUCHI-KASAI Kiyomiao (1i:if) m~

103

HIRENZAKI Satoru.1:t:il~

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24

207

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65 , 66, 75

12*~titxHONJO Yoshio

35*ra9~iz.

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HORBATSCH Marko59

HORI Toshihiko

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KANAI Yasuyuki~1t1:*z.

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65,66, 75~iR~':=:

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38, 40, 41 , 109, 113,

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117, 118

KANAZAWA Mitsutaka

IDEGUCHI Eiji

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IRNICH H.

1i*r€te~*KASE Masayuki

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KATAYAMA Ichiro

mB3~~t104

96, 130, 133, 135

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1Jo iTi tf
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107

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115, 117, 168, 169

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KAWAKAMI Minoru

81

47

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KAWAI Jun

52

ISHIBASHI Mie

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KASAGI Jirohta

1tif;J ~125
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124

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91~~11:-

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KANAZAWA Ikuzo

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59, 60, 61 , 62, 63 , 64,

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ICHIKAWA Ryuji

3, 6, 133, 139

96, 97, 103, 105 , 106,

158
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KAMIGAITO Osamu)lIra9g~t

145

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69, 112, 141

KAWAMA Tetsuo

ISHIDA Nobumichi~B31$:ii

116)11&:b:.9Ht 41
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ISHIHARA Masayasu~1tq: ¥ISHII Takayuki

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114, 121

KAWATSURA Kiyoshi)1100 i!!

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102

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31 , 3376~±-*~~ISHIZUKA Takeo

155 , 157, 158

41 , 42 , 43,46,47,~)IIJftE*c.

ISHIKAWA Masanobu

115

KIKUCHI Masahiro

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KIKUCHI Tadashi

ITO Hisao#l"iTi)..X

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KIM Jong ChanITO Yasuo#l"iTi*~91

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