ISSN 0289-842X

RIKEN
Accelerator
Progress Report
vol.

28

理化学研究所

The Institute of Physical and Chemical Research (RIKEN)RIKEN Accelerator Progress Report -U (Q)(Q)4
January-December U~ ~i~ it. ~m ~ jiJTThe Institute of Physical and Chemical Research (RIKEN)
Wako-Jhi, Saitama, 351-0 I JAPANEditors

A. GotoT. Ichihara

T. Kambara

T. Kobayashi

Y. Kobayashi

T. Okada

1. Shimamura M. Takami
S. Yamaji

F. Yatagai

All rights reserved. This report or any part thereof may not be rep rod uced 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 t~econtents of the report.

CONTENTS
I.

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

II.

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

3

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

5

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

6

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

7

III.

RESEARCH ACTIVITIES

1.

Nuclear Physics

Stochastic Variational Method for Few-Nucleon Systems

9

Microscopic Multicluster Description of Light Exotic Nuclei .........................

10

Configuration of the Two-Neutron Halo of 11 Li and Gamow-Teller Transition ........

11

Neutron Halo Effects in Direct Neutron Capture and Photodisintegration ............

12

Deformed Woods-Saxon Potential Approach to the Structure of 11 Be ................

13

Beta-decay of Neutron-rich Nuclei 17B and 19C ......................................

14

Beta-decay of 17Ne and Isospin Symmetry.. ............. .. .. ....... .. ...............

15

Giant Resonances in Nuclei with Neutron Skin .. . ...................................

16

Transfer and Fusion Reactions of Unstable Nuclei ...................................

17

Mass Dependent Parameter Set of the Relativistic Mean Field Theory for
Unstable Nuclei and Nuclear Matter ..................... . ... . ......................

18

Relativistic Mean Field Theory for Unstable Nuclei and the Birth of Neutron Stars ..

19

Study of the Triaxial Deformation in the Relativistic Mean Field Theory .............

20

Effective Interaction in Asymmetric Nuclear Matter .................................

21

Stationary Solution of Time Dependent Density Matrix Formalism... .... . ....... . .. .

22

Strength for Isoscalar Modes in Diabatic Picture ....................................

23

Possible Interpretation of Extremely Low Energy Odd Spin States ...... . ............

24

The Ml Ttransitions and the New SU(3) in Superdeformed Nuclei.. ............... ..

25

Systematics of Alpha Q-values: Alpha Decay Life Times of Unstable Nuclei..........

26

Shell Model on a Random Gaussian Basis ...........................................

27

E-Hypernuclear Production Spectra on a 9Be Target ................................

28

Nuclear Mesonic Exchange Currents .................................................

29

QCD Phase Transition in the Dual Ginzburg-Landau Theory..... ...................

30

Measurement of Fusion Cross Section with Neutron Halo Nucleus 11 Be ..............

31

2.

Spectroscopy of 13Be Using 12Be Radioactive Beam. .... ..... .. .. ..... ...... ..... ....

32

Excited States of 12Be in the Vicinity of He-Thresholds ..............................

33

Systematic Behavior of Ejectile Spin Polarization in the Projectile
Fragmentation Reaction .............................................................

34. Interaction Cross Sections and Radii of 11 C and 12N .................................

35

Radii of Na Isotopes and the First Direct Evidence of Neutron Skin .................

36

Coulomb Excitation of 32Mg ........................................................

37

Beta-decay of Neutron Rich Nucleus 14 Be ...........................................

38

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

39

Magnetic Moment of Proton Drip-Line Nucleus 9C ..................................

40

Magnetic Moment of Very Neutron-rich Nucleus 17B .................................

41

Magnetic Moment of 17N ............................................................

42

Asymmetry Parameter of 23Mg Beta Decay .........................................

43

Nuclear Moments of 179Ta ....................................... . ..................

44

Nuclear Moments of 180mTa by Laser-RF Double-Resonance Spectroscopy....... .....

45

27 AI( d ,2He) Reaction Studied at Ed = 270 MeV ............................ .. .......

46

GT + Strength Distributions in N = 15 Isotones .....................................

47

Excitation of Spin-dipole States by the 12Ce2C,12N)12B Reaction at
EjA = 135 MeV....................................................................

48

Tensor Analyzing Power of the 12C( d,2;He)12B Reaction at 270 MeV .................

49

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

50

Coulomb Excitation of 174Hf K-Isomer: ,-Ray Spectroscopy with
High-Spin Isomer Beam... ........ .. .... ..... . . .. ....... . ..................... .. ....

51

High-Spin States in 148Tb ...........................................................

53

New Isomers in 174Hf ...............................................................

54

Excitation Energy of Hot Nuclei Produced in 40 Ar + 116Sn Reaction at
EjA = 30 and 37 MeVju ...........................................................

55

Angular Momentum Dependence of the Giant Dipole Resonance in Hot Nuclei. .. ... .

56

Development of Quasi-Monoenergetic Neutron Field with the Use of 80 to 135 MeV
Protons Injected on Lithium ........................................................

58

Muon Catalyzed Fusion in Thin Deuterium Films andSlow Negative Muon Production ....................................................

59

Atomic and Solid-State Physics
Low-energy Electron Impact Ionization of Atomic Hydrogen

61

Mechanism of Enhancement of Some High-lying Resonance Series in
Photoionization Spectra of Excited Helium ..........................................

62

High-lying Doubly Excited Resonances in the Photo detachment of H- ...............

63

3.

The Energy Relaxation of Subexcitation Electrons in H2 Gas ........................

64

Single and Double Ionization of Helium by Slow Protons and Antiprotons

65

Ionization and Charge Transfer of Atomic Hydrogen in Collision with
Multiply Charged Ions.... .. ... .... .............. .... ... .... .. .. ....................

66

Magnetization of Ferromagnetic Clusters ............................................

67

Lifetimes of the 3p 2p Levels of Na-like Nb ..........................................

68

Mg-like Intercombination Lifetimes for Zr and Nb ...................................

69

Beam-Foil Spectra of Highly Charged Neon .........................................

70

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

71

Binary Encounter Electron Production at Relativistic Collision Velocities

72

Charge Distribution of Kr Ion Passing through Thin Carbon Foil at
36 MeV/nucleon....................................................................

74

Momentum Distribution of Recoil Ions from 8.7 MeV 07+-He Collisions.............

75

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

76

Laser Spectroscopy of Atoms in Superfluid Helium ..................................

77

Muonium Centers in Crystalline Si and Ge under Illumination.............. .........

78

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

79

Hyperfine Magnetic Field of 61 Ni in Spinel Chromite Cuo.gNio.1 Cr204 ................

80

57Fe Mossbauer Studies of YSr2Cu3-xFex07-y

81

Radiochemistry and Nuclear Chemistry

Multitracer Study on Transport and Distribution of Metal Ions in Rice Plant

83

Multitracer Study on Transport and Distribution of Metal Ions in Soybean Plant

84

The Study of Behavior of Various Elements in Atmosphere-plant System by
Multitracer Technique ..............................................................

85

Study on Uptake and Excretion of Trace Elements in Rats using
the Multitracer Technique ...........................................................

86

Multitracer Study on Distribution of Radioactive Nuclides in Rats:
Metabolism and Accumulation in Various Tissues, Organs and Body Fluids

87

Distribution and Behavior of Trace Elements in Zinc Deficient Rats Using
the Radioactive Multitracer Technique ....... ............. ..........................

89

Tissue Distribution of 16 Elements in Mice: An Application of Multitracers to
Animal Experiments ................................................................

90

Studies on Transcuticular Movement of Multitracer from Plant Leaf Surfaces ........

91

Simultaneous Analysis of Solid-Liquid Adsorption Behavior of
Various Elements using Radioactive Multitracer: Activated Carbon Fiber and
Non-ionic Macro-reticular Copolymer ...............................................

92

Studies on the Ion Exchange Adsorption Behavior of Strongly Acidic Resin
NAFION and its Application to Analytical Chemistry...............................

93

4.

Influence of Metal Humate Formation on the Adsorption ofMultitracer on Kaolinite ............................................................

94

Adsorption Behavior of Lanthanides Affected by Humate-complex ...................

95

Production of Multitracer Nuclides by Irradiation with an 40 Ar Beam. . . . . . . . . . . . . . . .

96. Target Residues from the Interaction of Copper with 40 MeV/nucleon 40 Ar Ions .....

97

The Mass Yield Distribution of Target Residues from the Interaction of Iron with
135 MeV/nucleon 12C Ions.... ................. ..... ............. ... .. .... ......... .

98

Angular Distribution of Recoil Products in the Heavy-Ion Reaction of Gold ..........

99

Incomplete Fusion of the 141 Pr Induced by 38-95 MeV /u 40 Ar Ions... ........... .. ..

100

TDPAC of 99Ru in YBa2Cu306.8 and YBa2Cu306 ...................................

101

A New Set-up for In-Beam Mossbauer Spectroscopy at RARF .......................

102

Extraction of Intense Slow Positron Beam from Various Targets Irradiated withp+ and d+ Ions .....................................................................

103

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

104

Radiation Chemistry and Radiation Biology

Time and Depth Resolved Dynamics of Excited States in Ion Track in
Condensed Matter ..................................................................

105

Measurements of Heavy Ion Beam Qualities .........................................

106

The Profile of Chemical Damages in Polymers Induced by Heavy-ion Irradiation .....

107

Radiation Effects of Ion-particles on Various DNA Structures (2) ....................

108

Analysis of Mutations in the Human HPRT Gene Induced by Accelerated
Heavy-ion Irradiations ............... :..............................................

109

Induction of Apoptosis in CHO Cells Exposed to Accelerated Neon Ions .............

110

Biological Effectiveness of Heavy-Ion Beams on Cultured Mammalian Cells ..........

111

DNA Double Strand Breaks Induced with 135 MeV/nucleon Ne Beam...............

113

Effects of Charged-particle Beams on 11 Mammalian Cell Lines ......................

114

Effects of 135 MeV/nucleon Carbon Ion on Cultured Cells Derived fromSquamous Cell Carcinoma ..........................................................

115

Sensitivity of Normal Human Skin Fibroblasts after Carbon Ion Irradiation ..........

116

Mutation Caused by Heavy Ion Particles and X-rays ................................ . 117

5.

Effects of Accelerated Carbon-Ion on the Induction of Dominant Lethality in
the Teleost Fish, Oryzias latipes .....................................................

118

Biological Dose Distribution of Carbon-12 Spread-Out-Bragg-Peak for
Thmor Controls ..................................... '. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

119

Instrumentation

Production of a Low-Energy Polarized Neutron Beam

121

Germanium Counter Telescope for Gamma-Ray Position Sensitive Detection...... ...

122

6.

7.

A New Position Sensitive Silicon Detector for Experiments of Super Heavy
Nucleus Search .....................................................................

123

Status of the Detector System at SMART-FPl ......................................

124

Construction of the Deuteron POLarimeter DPOL at theSecond Focal Plane of SMART ......................................................

125

PPAC for Beam Profile Monitor at the RIPS. .. .. ................. .. .. .. .. ..........

127

Polarized Xe Stopper for the Measurement of Magnetic Moment of Unstable Nuclei..

128

A Recoil-Ion Momentum Spectrometer for Atomic Physics Experiments

129

Attenuation Length of Scintillation Photons in
Liquid Rare Gases and their Mixtures ...............................................

130

A Blow-in Type Windowless Gas Target ........................................... ..

131

Observation Program of Cosmic Ray Ions with theFirst Brazillian Scientific Satellite ...................................................

132

Collinear Resonance Ionization Spectrometer with Diode and UV Lasers .............

133

Design of Tritium Gas Handling System for Muon Catalyzed Fusion Experiment at
RIKEN-RAL Muon Facility .........................................................

134

Production Tests of Radioisotope Beam by SLOW Beam Channel ...................

135

Construction of a Heat-Pipe Oven System for Laser Spectroscopy ofRadioactive Isotopes ................................................................

136

Material Analysis

In situ Analysis of Liquid Samples by Vertical Beam PIXE

137

X-ray Satellite Caused by Radiative Auger Effect. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

138

Analysis of Trace Elements in Fish Otoliths by In-Air PIXE .........................

139

Microstructure and Chemical Composition of Duckbilled Dinosaur Eggshell..........

140

Heavy-ion Rutherford Scattering Applied to the Investigation of Fire Causes. . . . . . . . .

141

RBS Study of Tb-Implanted Sapphire (I)142

Miscellaneous

Design of a Moisture Monitor Based on H-D Exchange in a Glass Surface Layer ......
IV.

V.

143

NUCLEAR DATA

Status Report of the Nuclear Data Group

145

Evaluation of Nuclear Structure Data of A = 120

146

DEVELOPMENT OF ACCELERATOR FACILITIESStatus of RIKEN 10 GHz Electron Cyclotron Resonance Ion Source (ECRIS)

147

Status of the RIKEN Polarized Ion Source ..........................................

148

Modeling of ECRIS Beam-Intensity Upgrading-Technologies .................. . ......

150

Development of High-T e ECRIS Plasma Diagnostics .................................

152

Construction of a High Density Polarized 3He Gas Target ...........................

154

VI.

Monitoring System of Single Thrn Extraction in Cyclotrons. . . . . . . . . . . . . . . . . . . . . . . . . .

156

Study of the Beam Transport between the AVF and Ring Cyclotrons ................

158

Development of aNew Type of Single-Bunch Selector ...............................

160

Replacement of Computer for the RRC Control .....................................

162

Construction of a New Injector System for RILAC ...................................

163

Design of RIKEN 18 GHz Electron Cyclotron Resonance Ion Source (ECRIS) ........

165

Design of a Beam Transport Line between the 18 G Hz ECRIS and the RFQ Linac ...

166

Cold Model Test of the Variable Frequency RFQ Resonator..... .............. .. . ....

168 .

Hollow Beam Formation in the Extraction Region of ECRIS ........................ .

170

Beam Dynamics Study in Variable Frequency RFQ Linac for RILAC ................

172

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

174

Optics Design for the RIKEN-RAL Muon Channel..................................

175

Development of a Pulsed Kicker Magnet for the RIKEN-RAL Muon Beam Line. . . . . .

176

Conceptural Design of Accelerator Complex for RIKEN RI Beam Factory ............

178

Double Storage Rings for Multi-Use Experimental Storage Rings Proposed for
RIKEN RI Beam Factory ...........................................................

180

Accumulator-Cooler Ring for Multi-Use Experimental Storage Rings Proposed for
RIKEN RI Beam Factory...........................................................

182

RADIATION MONITORING

Leakage Radiation Measurements in ~he Ring Cyclotron Facility

183

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

184

A Film Badge Reading System for the Radiation Safety Control .....................

186

Measurement of Activities Induced by 135 MeV lu 28Si Incident on an Iron Target
with the Activation Method .........................................................

187

Neutron Dose Equivalent near a Thick Iron Target Induced by 135 MeV In Ions. .. .. .

188

VII.

LIST OF PUBLICATIONS ......... . ....................... ........... ................... 189

VIII.

LIST OF PREPRINTS ................................................................... 194

IX.

PAPERS PRESENTED AT MEETINGS .................................................. 196

X.

LIST OF SYMPOSIA

205

XI.

LIST OF SEMINARS

206

XII.

LIST OF PERSONNEL

209

AUTHOR INDEX

I. PREFACE

This report summarizes research activities at the
RIKEN Accelerator Research Facility for the year of
1994. The research program has been coordinatedin the framework of the project entitled by Multidisciplinary Researches on Heavy Ion Science. It involves a variety of research fields; nuclear physics,
atomic physics, nuclear chemistry, radiation biology,
condensed matter physics in terms of accelerator orradiation, 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 whole activities involve 12 laboratories in
RIKEN and more than 400 researchers including outside users.
The research activities have steadily developed
through the year at the major accelerator, t he RIKEN
Ring Cyclotron (RRC) , and its subordinate accelerators, the energy-variable heavy ion linear accelerator(RILAC) and the K = 70 AVF cyclotron, which havealtogether delivered a beam time (on the target) of
more than 8000 hours.
Besides, t his year should be marked as an epochmaking year for the Facility by having achieved approval of two major proposals, construction of an upgraded facility called the RIKEN Radioactive Beam
Facility and setup of an internat ional collaboration
program on spin structure funct ions. Both of the
projects are due t o be initiated in FY 1995.
Continuous efforts have been taken to grade up thecapabilities of the accelerators. Most importantly aproject to drastically improve the beam intensities at
RILAC is in progress. A set of 18 GHz ECR ion source
and a frequency-variable RFQ is under construction
to replace the upstream end of the accelerator. The
completion is expected in 1995.
The heavy ion research program at the Facility has
enjoyed another year of continuous development. Nuclear physics researches have heavily focused on thestudies on unstable nuclei, in particular in terms of radioactive beam experiments. Studies on nuclear synthesis beyond the drip line and towards the superheavy elements have continued involving the identification of lOHe and successful synthesis of Z = 106 isotopes through an incomplete fusion-like process, (40 Ar,axn) . Spectroscopy on extremely neutron rich nuclei
has made a further progress: Properties of soft dipole
excitation and other excitation modes in halo (or skin)nuclei have been studied with a variety of direct reaction processes. Methods of laser spectroscopy and,B-r-neutron spectroscopy have been also employed forthe study of nuclear structure. Studies have extended

to heavier nuclei of a region around 32Mg including theradius measurement of a series of Na isotopes whichwere carried out at GSI. Exotic properties are anticipated for reactions induced by neutron rich nuclei.
Results have been obtained on sub-barrier fusion reactions of this context. Radioactive-beam experiments
offer unique opportunities to study reaction rates ofastrophysical interest. Among others Coulomb dissociation cross section of 8B has been successfully measured in relation to the solar neutrino problem. The
studies on unstable nuclei heavily depend on the development of the radioactive beams (RIB) at the Facility. Uniquely the Facility provides three different typesof radioactive beams: Firstly intermediate-energy RIB
by means of projectile fragmentation (PF) have been
most frequently used, by amounting to about 40% of
the whole RRC beam time. The second type of RIB is
the spin-polarized beam which is also produced via PF
process covering a wide range of nuclear species. The
beam has been used to determine nuclear moments (gfactor and Q) of unstable nuclei ranging over a dozen of
isotopes including exotic nuclei such as 17B. The third
type of RIB is the high-spin isomer beam which is produced via reverse-kinematics fusion reaction. Beamsof heavy isomers with spins close to 30 h are obtainedwith considerable intensities. Such beams were so far
used to study Coulomb excitation of high-spin isomericstates.
In the field of nuclear physics spin-isospin response
is another major subject, where reactions (d,2He) and(d,d(O+)) as well as heavy-ion exchange reactions areprimarily concerned. A wide acceptance and high resolution spectrometer, SMART, of Q-Q-D-D type anda spin-polarized ion source for deuteron have served
for such experiments yielding well qualified informative results.
The heavy ion researches are extended over a variety of domains beside nuclear physics. Atomic physics
has been pursued, enjoying an extremely wide energy
range of heavy ions available with the ECR ion source,
RILAC and RRC. Atomic collisions in the relativistic region have been studied at RRC. The first measurement has been performed of momentum distributions of relativistic electrons ejected by quasi-binary
collisions of a target electron with a heavy projectile. A new technique of cold-target recoil-ion momentum spectroscopy (COLTRIMS) has been introduced
to facilitate high-precision ( with a resolution better
than 0.2 atomic unit) and high-efficiency spectroscopyon the ionization and electron transfer processes in
ion-atom collisions. Beam foil spectroscopy of highly
charged ions has been pushed forward to both heavier
1elements and a new region of wave length. Nb and Zr
ions were studied in the region of VUV while Ne ionswere studied in the UV and visible regions. Basic information for laser and plasma applications is gained.
In nuclear chemistry remarkable development hascontinued in application of the methodology of multitracer. Multitracers have been extensively utilized inchemical, environmental and biolog.ical investigations.
Twelve research items have been pursued involving alarge number of groups from universities and other institutions. Among others a notable development has
been attained in the study of trace elements in animal bodies. For instance behavior of more than 20
trace elements has been clarified in rats and mice under different conditions such as normal, Zn-deficient,and Vitamin D-excess. The data are useful not only
for bioinorganic chemistry but also for dietetics, toxicology, pharmacology and medics in general. Anothermajor effort has been paid to develop the setups for
Coulomb excitation Mossbauer spectroscopy. A test
experiment was successfully performed at the AVF Cyclotron using a 40 Ar beam.
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. The pinningeffect of magnetic flux through superconducting materials caused by irradiation of high-energy heavy ions isunder investigation.
Irradiation effects with heavy-ion beams are studiedin several respects. One is concerned with radiation
biology. Effects of high LET are studied for a variety of biological samples. As a recent development it
has been proved for the case of a tabacco plant thatheavy ion irradiation is strikingly effective to induce
new types of mutagenesis as compared to the otherstandard mutagen treatments. Basic studies for heavyion-beam cancer therapy are continued 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 are irradiated to
study characteristic damages, including detectors andbiological samples. In particular studies on electronic
devices are made in collaboration with National Space
Development Agency of Japan.
The Facility carries on an international research
program on muon science in collaboration with the
Rutherford-Appleton Laboratory. The muon beam facility at the proton synchrotron ISIS has been completed this year. It will start operation in early 1995 toaccommodate versatile research programs using powerful pulsed muon beams.
Finally, having achieved approval of two new
projects, the Facility is moving towards a new stageof global development. The project of the RIKEN Radioactive Beam Facility involves construction of superconducting separate-sector cyclotron with K-number
around 2400 to work as the energy booster on top of
the existing RRC. Beam energies of heavier elements
are to become sufficiently high to produce PF radioactive beams over a drastically wide region of unstable
nuclei. The cyclotrons are to be accompanied withdual rings of synchrotron to enhance the experimental
perspectives. We anticipate that the new Facility could
make a central contribution to the world community ofnext generation RIB science. Most optimistically the
Facility would be completed somewhere around 2002
or 2003. Another project on relativistic-energy spin
physics is formulated as the 2nd international research
program following the muon project. It is to be carriedout in collaboration with Brookhaven National Laboratory. The program aims at investigation of spin related properties of nucleons in terms of quark-gluon
framework by facilitating spin-polarized proton beams
in RHIC. This implies introduction of a new domainof physics into the whole RHIC program as well as aconsiderable expansion of the research area covered by
our Facility.

Masayasu Ishihara
Director
RIKEN Accelerator Research Facility

2

II.

OPERATION OF ACCELERATORSRIKEN Accel. Prog. Rep. 28 (1995)

RRC Operation
A. Goto, M. Kase, N. Inabe, T. Kageyama, 1. 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,* T. Maie,* T. Kawama,* T. Honma,* and Y. Yano
tinely been made; its total beam time was additional
30.5 days.
Because of the following troubles, a total of 15 daysof the scheduled machine time had to be cancelled. As
for the AVF cyclotron, the deflector sometimes became
not to work due to its unendurable leak current, a partof the RF slide-contacts of the movable shorting plate
was melted and burned, and the vacuum leak occurredfrom the magnetic channel due to beam hitting. The
first two troubles were also experienced last year. As
for the RRC, one of the connectors (made of brass) for
cooling of the main coils was broken due to corrosion,and the vacuum leak occurred between the aluminum

In this-year runs from November 1993 to October
1994, 32 kinds of combinations of ion species and energies were used for experiments, of which 13 kinds
were new ones. The total beam time was 199.5 days.
The AVF -RRC operation was performed for 147 days
(74%) and the RILAC-RRC operation for 52.5 days
(26%). The beam time of 162 days (81%) was devoted to nuclear physics experiments and that of 37.5
days (19%) to non-nuclear physics experiments. Table 1 summarises the characteristics of the accelerated
beams. Figure 1 shows the plots of the ions accelerated so far in the available region of energy-mass
space. Stand-alone use of the AVF cyclotron has rou-

Table 1. RRC beams accelerated during Nov. 1993-0ct. 1994.
Particle

ChargehInjector

27.6

5

AVF

90t

1

29 .0

5

AVF

lOOt

0 .5

30 . 1

5

AVF

llOt

30.45

5
5
5
5
5

113 t
l20t
135
135
135

6
6
6

31.2
32.6
32 .6
32.6
27 .9
29.0
32.6

AVF
AVF
AVF
AVF
AVF

5
5
5

AVF
AVF
AVF

7
4
14

H2

d
pol. d
12C

1

RFF
(MHz)

Energy(MeV I nucleon)

Beam time(days)

1
1.5
3
4 .5
24

6

29.0

5

AVF

92
100
135
lOOt

7
7

24.6
32.6

5
5

AVF
AVF

70
135

0.5
6 .5

15N
160
180

7

30 .5

8

5

AVF

115
135
100

11.5

32.6

5
5

AVF

8

l3 C
14N

AVF

16

2

20Ne

10

29.0
32.6

5

AVF

135

2

22Ne

10

30.1

5

AVF

110

12.5

24Mg
28Si
36 Ar
40 Ar

12
14

29.0

5

AVF

100

5

32 .6
18.8
18.8

5

AVF
RILAC
RILAC

18.6

11
11
10

135t
7 .5 t

RILAC

7.5
9t

14
17

32.5
28.1

9
5

RILAC
AVF

35 t
95

3 .5
6.5

13
25

20.0

10
9

RILAC

10.5

0.5

32 .7

136Xe

21
23
31

18.6
18.6
28.0

11
10
9

RILAC
RILAC
RILAC
RILAC

8
1.5
2

170&

24

18.0

11

RILAC

36t
7.4t
9
26
7t

6.5

Total

199.5

84 Kr

5
5
6

22

1
5
19.5
3.5

2.5

t New beams

Sumijyu Accelerator Service, Ltd.

3

2 10
200

•

Ions Accelerated(A pril 1987 - October 1994)

150

Co

<!.)

u
::l

135
129

c

A VF Inj e cti on
h AyF = 2 , hRRc= 5

:;
<!.)

~

>-

100

0

~

IJ..l

Z

I.Ll

/'
50

A VF Injecti o n
h A y F = 3 , hRRc = 5•.···1·············:·.. • • •

35.6

• ••
•

10
7
0
I

•

I

Lin a c I njecti on

• I

• •
•

I

~NArL NCu
1111111

Hco~

I

Ar

I

I

Zn Kr

h RR c =9 , 10 , 11

I

I

I

Xe

Er

Ta

I

I

Bi U

Atomic Mass

Fig. 1. RRC beams a ccelerated during Nov. 1993- 0ct.
1994.

gasket and the ceramics that are used in the coaxial rf
power feeder.
During the period of six-weeks overhauls in summer, the following big works were done. Firstly, weabandoned a total of 56 connectors (using a -rings)
that were used inside the movable boxes of the rf resonators of the RRC for cooling of them , and instead
directly connected cooling pipes by welding. Owing
to this repair , the vacuum leak in the rf resonators ,which sometimes troubled us before, have not occurredsince then. The preesure inside the acceleration chamber is now about 10- 6 Pa. Secondly, we replaced4

one of the three mini-computers (Mitsubishi M60j500)
used for the control of the accelerator complex by a
new one (Mitsubishi M60j AR) , which is an upgradedmachine of M60j500. The basic architecture of thecontrol system has remained unchanged. Some component parts of the replaced computer will be stocked
as spares for the remaining old two computers.
We have recently begun to make use of parasitemode operation. The first trial was made between
E3 and E6 experimental rooms, where the sub experiment on a counter test and the main experimentwith RIPS were performed, respectively. Switching
the beam delivery could be made in a second eachtime. A combination of the single-bunch selector on
the injection beam line of the AVF cyclotron and thetwo beam detectors each using a micro-channel plate(MCP) , which were developed last year, has routinely
been used both as phase monitors for stabilizing themagnetic fields of the two cyclotrons and as monitors for single-turn extraction. A single-bunch selector functioning with a repetition rate of as high as 1
MHz has also successfully been developed using a highspeed semi-conductor device. We tried and succeededin accelerating argon ions of lower energies in the AVF
cyclotron (2 .75 MeV jnucleon) with the third harmonic
acceleration mode instead of the second to meet users 'demand . This will enable us to cover the so far nonavailable region of energy-mass space from 40 to 70
MeV jnucleon as shown in Fig. 1, although only one
in every three beam bunches can be accelerated by the
RRC . The development of a high-density polarized 3He
gas target system is also in progress .
A new injector system of the RILAC consisting of asingle-stage high-field 18 GHz ECR ion source and avariable-frequency RFQ linac is now under fabrication
for completion by the spring of the next year. As for
the RFQ linac, a half-scaled model for the cold test of
the cavity was completed at the end of the last year,
and various measurements were made on its rf characteristics. The measurements showed that the model
had good performance in accordance with the design.

RIKEN Accel. Prog. Rep. 28 (1995)

RILAC Operation
E. Ikezawa, M. Hemmi, T. Chiba, Y. Chiba, S. Kohara, T. Aihara,* T. Ohki,* H. Hasebe,*
H. Yamauchi,* 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. 1994. Table 2 summarizes the time sharing for individual research groups. The percentage of the beamtime for RIKEN Ring Cyclotron (RRC) was about 42%of the total; ions of 36 Ar, 40 Ar, 84Kr, 130Te, 136Xe, and170Er accelerated by RILAC were injected to RRC.
Table 3 gives the statistics of ions used in this year.
We began accelerating Zr 12 +, Pd 12 +, Te 9 +, and Ce 14+
at frequencies of 32, 28, 18.8, and 28 MHz respectively. The percentage of the beam time for metallicions amounted to about 19% of the total.
This year we had the following machine troubles.
(1) The tetrode (RCA-4648) used in the No.5 final
rf amplifier was replaced with a new one, because theemission currents from the filament have declined. The
tube has been used for fourteen years. (2) A refrigerator and coolant oil for the 8 G Hz ECR ion source were
replaced with new ones because the plasma chamber ofTable 1. Statistics of the operation from Jan. 1 throughDec. 31, 1994.
Day%

Beam time

167

45.8

Frequency change

II

3.0

Overhaul and improvement

55

15.1

Periodic inspection and repair

24

6.6

Machine trouble00.0

Scheduled shut down

108

29.6

Total

365

100

Table 2. Beam time for individual research groups.
Day%

Atomic physics

43

25.7

Solid-state physics
Nuclear chemistry

6
7

4.2

Radiation chemistry

16

9.6

Accelerator research

25

15.0

Beam transportation to RRC

70

41.9

167

100

Total

3.6

Table 3. List of ions used in this year.
Ion

Mass

He

4

C

12

4

8

Charge state

Day

7

N

14

3

5

0

16

3

5

Ne

20

3,4

8

Ar

36

5

Ar

40

5
5,6,8

63

Kr

84

13

10

Zr

90

12

4

Zr

91

12

2

Nb

93

12

4

Pd

106

12

Te

130

9

10

Xe

136

9, 15

24

Ce

140

14

Er

170

11

8

Bi

209

II, 192

the ion source was not cooled very well. (3) A chamber
for the electrostatic quadrupole lens of the ECR ion
source had a small vacuum leak with the damage ofdiverged beams hit on it for long time. We changed
the chamber into a spare one.
We carried out the following machine improvements.
(1) The power supplies for the drift tube magnets usedin the No.6 resonator and for the quadrupole magnetsof the beam transport line were remodeled by replacing
the obsolete power transistors with the modern ones.
(2) In the rf system of six resonators, a wide band
amplifier (output power of 500 W), and both of power
supplies of the control grid (250 V, 2.5 A) and thescreen grid (1.5 kV, 2.2 A) for the final vacuum tube
have been replaced with new ones, because they were
worn out after many years operation.
To further simplify and stabilize the operation of
the accelerating voltage, both tuning and amplitude
regulation circuits for each main resonator are newly
designed and being manufactured at present.
We have tested to obtain metallic ions by use of amaterial such as Pd, La203, Te02, and Ce02. Ion
currents with these rods were very stable. At present
we can supply ions oI10 gaseous and 41 solid elements.

Sumijyu Accelerator Service, Ltd.

5

RIKEN Accel. Prog. Rep. 28 (1995)

AVF Cyclotron Operation
A. Goto, T. Kageyama, M. Kase, N. Inabe, S. Kohara, M. Nagase, T. Nakagawa, K. Ikegami , O. Kamigaito,
1. Yokoyama, J. Fujita, H. Isshiki,* H. Akagi,* R. Ichikawa,* N. Tsukiori ,* R. Abe,*K. Takahashi ,* T. Maie,* T . Kawama,* T. Honma,* and Y . Yano
In this-year runs from November 1993 to October
1994, thirty-four kinds of combinations of ion species
and energies were used for experiments, of which thirteen kinds were new ones. The total beam time was
177.5 days. The beam time for polarized deuterons
amounted to 24 days, the longest among the accelerated beams. Table 1 summarizes the characteristics ofthe accelerated beams.
Stand-alone use of the AVF cyclotron has routinely
been made while the RRC is operated with the RILAC beam injection. The total beam time for it
was 30.5 days, about four times that of the last year.
Those beams were used for the production test of slow
positrons, measurement of nuclear fusion cross sections, and radioisotope production for Mossbauer spectroscopy and laser nuclear spectroscopy.

To meet users ' demand for lower energies, we triedand succeeded in accelerating argon ions of 2.75
MeV /nucleon with the third acceleration mode insteadof the second, for which the cyclotron was originallydesigned. The beam intensity was about 1eJ.LA. This
beam was used for the experiment of M6ssbauer spectroscopy. We also tested to accelerate krypton ionswith a mass-to-charge ratio of 4.2 at 4 MeV/nucleon.
The beam intensity was as low as 10 nA , because the
ECR ion source had an unknown trouble with respect
to the beam intensity at that time. Taking accountof the normal intensity of 20 J.LA from the ECR ion
source for 84Kr20+ , however, the beam intensity fromthe cyclotron is expected to be about several hundredsof enA. The krypton ion is the heaviest that can be
accelerated with the cyclotron.

Table 1. Ions accelerated with the AVF cyclotron during Nov. 1993-0ct. 1994.
Particle Charge RF freq.
EnergyBeam time(days)(MHz) (MeV /nucleon)pdpol. d
Q:

1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
2

19.35
23.0
13.8
14.0
14.5
15.05
15.23
15.6
15.7
16.3
16.3
12.3
16.3
18.5
19.0
16.3
15.5

9.9*
14.0*t
5.0 t
5.2*
5.5 t
6.0 t
6.1 t
6.4t
6.5*t
7.0
7.0*
4.0*
7.0
9.0*t
9.5*t
7.0
6.3*t

0.5
2.5
1
0.5
0.5
1
1
1.5
0.5
3
6.5
2.5
4.5
3.5
2
24
3.5

EnergyBeam time
Particle Charge RF freq .
(days)(MHz) (MeV /nucleon)
12C
5.1
7
4
13.95

13C
14N
15N
16 0
18 0
2°Ne
22Ne
24Mg
27 Al
28Si
40Ar
84Kr

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

14.5
16.3
14.5
12 .3
16.3
15.25
16.3
14.5
16.3
15.05
14.5
16.0
16.3
15.4
14.05
12.3

5.5
7.0
5.5
4.0
7.0
6.1
7.0
5.5
7.0
6.0
5.5
6.7*
7.0t
2.8*t
5.2
4.0t
Total

4
14
16
0.5
6.5
11.5
2
22
2
12.5
5
4
1
4.5
6.5
177.5

* Served for stand-alone use of the AVF cyclotron.
t New beams

As a monitor for single-turn extraction, a combination of the single-bunch selector on the injection beamline and the beam detector with a micro-channel plate(MCP), which was developed last year, has routinely
been used. This monitoring system is indispensable, inparticular, for the acceleration of polarized deuterons.
It has also been used as a monitor for stabilizing themagnetic field of the cyclotron.
During the past one year there have still been two
kinds of serious troubles with respect to the following
Sumijyu Accelerator Service, Ltd .

6

cyclotron components as in the last two years: a partof the RF slide-contacts of the movable shorting plate
was melted and burned twice; and the deflector became not to work five times due to its unendurable
leak current. In addition, the vacuum leak occurredfrom the magnetic channel due to beam hitting. In
the summer-time overhaul, it was found that one of
the bolts attaching the copper membrane to the sectors, the membrane covering trim coils in rough vacuum, was cut off by a mechanical stress and dropped
down on the dee electrode.

RIKEN Accel. Prog. Rep. 28 (1995)

Tandetron Operation
E. Vagi, T. Urai, and M. Iwaki
The Tandetron was operated for 85 days for experiments except for machine inspection, beam test, repair
and so on in the period from Nov. 1, 1993 to Oct. 31,
1994.
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.,at present, Muon Science Lab.).
(b) Behaviour of Xe atoms implanted into iron
(Metal Physics Lab. , at present, Muon Science Lab.).
(c) RBS analysis of Tb-implanted sapphire crystals(Surface Characterization Centre).

(d) Characterization of Ni films grown on MgO by
biased dc sputter deposition (Metal Physics Lab., atpresent, Muon Science Lab.).
(2) Nuclear Reaction Analysis (NRA)(a) Lattice location of hydrogen in niobium alloys bya channelling method (Metal Physics Lab., at present,
Muon Science Lab.).
(3) Particle Induced X-ray Emission (PIXE)(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.).

7

III.

RESEARCH ACTIVITIES1. Nuclear Physics

RIKEN Accel. Prog. Rep. 28 (1995)

Stochastic Variational Method for Few-Nucleon Systems
K. Varga and Y. Suzuki[few-body systems, stochastic variational method.]
The investigation of the few-nucleon systems using
realistic nucleon-nucleon interaction, derived from twonucleon scattering data, is always in the centre of theinterest as we want to know to what extent we candescribe a nucleus as a system of interacting nucleons.
The solution of the nuclear many-body Schrodingerequation, however, is always a difficult task especiallyfor few-fermion systems where the collective or statistical models are not applicable. We elaborated
a fully microscopic approach based on a variational
method with stochastic selection!} of the important basis states. The wave function of the system is taken as
antisymmetrized product of functions of relative motion between the nucleons. Various rearrangements aresuperposed to take into account various types of correlations among the nucleons and to describe the nonuniform structure of the few-nucleon systems. The functions of the relative motions are expanded in terms of
nodeless harmonic oscillator functions of different size
parameters. The matrix elements are evaluated analytically in a unified and systematic way in three steps:(i) Evaluating matrix elements with Gaussian packets in the single particle coordinate representation, (ii)Transforming to relative and center-of-mass coordinate
representation and (iii) Transforming to nodeless harmonic oscillator function bases with definite angularmomenta.
To test the accuracy of our approach we solved thethree- and four-body Schrodinger equations using some
simple model forces and then compared our results toother solutions in the literature. For this test purpose
we useq the Malftiet-Tjon (MT), Volkov (see Fig. 1),
and Coulomb potential. (In case of Coulomb potential
we used electron and positron instead of proton andneutron.) For three-body systems with MT potential
we got -8.257 MeV and the dimension of the basis
was about 80. For Coulomb potential our results is-0.262005 a.u. on dimension of 150. Both results agree
in all digits with the best value in the literature.!) Fora four-nucleon system (a particle) with MT potential-30.00-30.05-30.10>" -30.15
CD~ -30.20e;; -30.25~ -30.30
W -30.35-30.40-30.45-30.50 -t-r-,....,..,r-r""l""T"'~.,........,r"T"T".,...,...,..,..,...,...,.,..........'"I"T"I..........-r-.-.......,

o

~

~

W

00 1001~1~1W100
N

Fig. 1. Convergence of energy as a function of the numberof basis states for a four-nucleon system with Volkov
interaction.

our result is -31.358 MeV (-31.357 MeV on dimension of 1000 in Ref. 2) with 250 basis states. For the
Coulomb interaction our result (0.51597 a.u.) agrees
up to 5 digits at dimension of 300 with results of othercalculations.
In summary, we tested our stochastic variational approach against the results of other few-body methods.
Our results agree perfectly with those of other models
even for Coulombic systems (negative positronium anddipositronium). Preliminary calculations show that
this method works for five- and six-body systems as
well. Encouraged by these results we plan to apply
this method to few-nucleon systems with a realistic interaction.
References
1) K. Varga, Y. Suzuki, and R. G. Lovas: Nucl. Phys.,
A571, 447 (1994).
2) See, for example, H. Kamada and W. Gloecke: ibid.,
A548, 205 (1992), and the references therein.

9

RIKEN Accel. Prog. Rep. 28 (1995)

Microscopic Multicluster Description of Light Exotic Nuclei
K. Varga, Y. Suzuki, Y. Ogawa, and I. Tanihata[exotic nuclei, cluster model, stochastic variational model.]We have developed a microscopic multicluster modelfor the description of light neutron rich nuclei. I) In thismodel a nucleus comprises several clusters (e.g. alphaparticle, 3H, 3He, or single nucleon clusters), and theintercluster wave function is taken as a superpositionof terms belonging to different arrangements, each defined by a set of Jacobi coordinates. Each term is thena superposition of products of nodeless harmonic oscillator functions (gaussians) of the individual Jacobi
coordinates with different widths. The wave function
constructed in this way is then considered a variational
trial function. This wave function, however, contains
prohibitively large number of overlapping terms (basis
states). We use the stochastic variational method toselect the "important" states: We select those basis
states from a randomly chosen set, which contributeto the ground state energy substantially. In this way
one can construct a flexible basis of low dimension.
We have successfully applied this model to microscopic description of 6He = a + n + nand 8He =a+n+n+n+n as three- and five-body systems. 2) The
ground state energies are reproduced very well. We
have calculated the proton, neutron and matter radiiand densities. The momentum distribution of fragments arising from the two-neutron removal reactions
is also determined. All results are in good agreementwith experiments.
Recently, we are studying the 9Li = a+ 3 H+n+n andthe 9C = a + 3He + p + p four-cluster systems. Various
descriptions of 11 Li assume a 9Li + n + n three-bodymodel to understand the halo structure. Information,
therefore, on the structure of 9Li is necessary to see towhat extent we can approximate the 9Li as a passive
core in the structure of 11 Li. The interaction crosssection and the magnetic moment of 9C have recently
been measured and the measurement of the quadrupole
moment is planned in the near future.
By describing all important subsystems of thesefour-cluster systems, such as 8Li = a + 3H + n, 8B =a + 3He + p, for example, we set the parameters of ourmodel to independent data. The model, therefore, contains no free parameters for 9Li and 9C, and reproduces
their ground state energies and root mean square radii
reasonably well. 3) The magnetic and quadrupole moments, except for the magnetic moment of 8B and 8Li,

10

are also reproduced well. The quadrupole moments of
9C are predicted to be - 5.04 e fm 2 and -6.11 e fm2. To
explore the possible halo structure, the nucleon density
distributions and the one- and two-nucleon removal
amplitudes were determined (see Fig. 1).

'x'0·'1:iIiO.~",-,==-","",,_...~ ,

"

'').,

"'-

''\

'\
"\

'\
"\
....

\

.... \
1x1 0. 4 +.-.~............,....,~...........,.....~.............,....,..........,............,.....~.;,....-.

o 0.5

1

1.5

2

2.5

3 3 .5

4

4.5

5

Fig. 1. Proton density distributions of 9C (short dashedline) and 9Li (dotted line) , and neutron density distributions of 9C (long dashed line) and 9Li (solid line).

Another application of the model is the descriptionof the Be isotopes. Starting from the 8Be, which has
a well-known a + a structure, by adding one neutron
at a time, we study the 9Be, lOBe, 11 Be and 12Be nuclei. It is interesting to investigate how the density
distribution and the structure (e.g. cluster and shellmodel configurations) of these isotopes change as we
increase the number of neutrons. The increase of theavailable experimental information on Be isotopes inthese years attracts considerable attention of the theoretical nuclear structure physicist, and make it possible
to check the model assumptions, and the results andthe predictions of different models.
References
1) K. Varga, Y. Suzuki, and R. G. Lovas: Nucl. Phys. ,A511 , 447 (1994).
2) K. Varga, Y. Suzuki, and Y. Ohbayashi: Phys. Rev.,
C50, 189 (1994) .
3) K. Varga, Y. Suzuki, and 1. Tanihata: submitted toPhys. Rev" C.

RIKEN Accel. Prog. Rep. 28 (1995)

Configuration of the Two-Neutron Halo of llLi
and Gamow-Teller Transition t
T. Suzuki and T. Otsuka[Neutron halo, GT /3 decay.]
Effects of neutron halo as well as meson exchange
currents (MEC) are studied for the Gamov-Teller (G T)/3 transition, 11 Li (3/2i.s,) ~ 11 Be (1/2-, 0.32 MeV) .
Effects of the haloof neutron (v) Pl/2 wave functionin 11 Li and 11 Be on one-body transition matrix elements as well as on two-body meson exchange currents
are studied. The vPl/2 wave function is obtained ina Woods-Saxon well to reproduce the single-neutron
separation energy (Sn), that is taken to be 160 keV 1 ,2)
in 11 Li. Calculated results are found to be insensitive
to the variation of Sn by f'V30 ke V. The shell model
configuration amplitudes obtained with the three setsof the Cohen-Kurath interactions are used. Effects of
the halo on the one-body terms are shown in Fig. 1.
The halo reduces the GT matrix elements by 35- 43%
and is important to get close to the experimental log
ft value. 3- 5 )One-pion exchange currents due to ~33-isobar excitations are also included. The halo affects the twobody terms in the GT matrix elements by 7-8%. The
exchange currents further increase the calculated log ft
value as shown in Fig. 1. We can conclude that the effects of the halo, the admixture of the sd-shell and theexchange currents are important to reduce deviations
from the observed log ft value of the GT transition.

dol

5.75

: expocross: elllc.

5.50
I

I

H.O.(b= 1.64fm)

40

HALO
HALO(MK)~" .0 .(b= L..-.- r--+d 33

HALO(MK)

I

I

7

6
EXP .

100

Fig. 2. Log ft values of the GT transition vs probability of the vpi/ 2-configuration. Dotted points show theobserved log ft value: log ft=5.58.

",m1

HALO

CT--H-f

60
60(pltJ 1 prob. (~)

log flFig. 1. Log ft values of the GT transition. The observed
value (log ft = 5.58 ± 0.01 5») is indicated by a verticalline with "EXP" . Symbols 0, x and 0 denote threesets of the Cohen-Kurat h wave functions: POT(8-16) ,TBE(8-16) and TBE(6-16) , respectively. Results withp5(sd)2 configurations admixed by the Millener-Kurathinteraction are shown by symbols ., <> and., whichcorrespond to 0 , x and 0 , respectively. Lower 3 setsof the results in the figure include the contributions
from the A33-isobar exchange current, while upper 3
sets include only one-body terms.

We now extend the shell model space to include thesd-shell. Allowing 2 valence particles to be excited into
the sd-shell by the Millener-Kurath interaction resultsin the increase of log ft by 0.08- 0.12.

Finally, we discuss the configurations of the twoneutron halo in 11 Li. What is the probability of
vpi/2 configuration in the halo of 11 Li? We decrease
the probability of vpi/2 configuration by lowering thesingle-particle energies of the sd orbits. Calculated
log ft values (see Fig. 2) increase almost linearly as
the probability decreases down to f'V60% and cross theobserved value at f'V65%. Thus, the GT transition isshown to play an indispensable role in identifying thestructure of two-neutron halo of 11 Li. It is indicatedthat the two neutrons forming the halo consisit of the
Pi/2 configuration with 60- 70%.
References
1) B. M. Young et al. : Phys. Rev. Lett., 71, 4124 (1993).
2) T. Kobayashi et al.: KEK Report , No. 91- 22 (1991)(unpublished).
3) F. Ajzenberg-Selove: Nucl. Phys., A506, 1 (1990); ibid.,
A433, 1 (1985).
4) E . Roeckl et al.: Phys. Rev., CI0, 1181 (1974).
5) T . Bjornstad et al.: Nucl. Phys., A359, 1 (1981).

Condensed from the article in Phys. Rev. , 50, 555 (1994) .

11

RIKEN Accel. Prog. Rep. 28 (1995)

Neutron Halo Effects in Direct Neutron Capture andPhotodisintegration
T . Otsuka, M. Ishihara, N. Fukunishi, T. Nakamura, and M. Yokoyama*[Neutron Halo, Direct Neutron Capture, 12C(n,,)13C.]
The direct neutron capture associated with E1 ,ray emission is discussed for the capture into an s orbit with neutron halo. An application to the reaction 12C(n,,)13C(1/2+) is presented, demonstrating anovel and enormous enhancement in the capture crosssection at low energy. The neutron halo is known to
be one of the most prominent and exotic effects seenin the ground states of some unstable nuclei such as
11 Li , 11 Be, etc. It has been suggested that the neutron
halo is not limited to exotic nuclei, and in fact can beseen in excited states of nuclei on or near the (3 stability line as well. For instance, the first 1/2+ state of
13C at Ex rv 3 MeV is predicted, by the recent Variational Shell Model calculation,1) to have the neutron
halo structure. We shall consider this 1/2+ state as
an example, and demonstrate that the direct neutron
capture cross section is indeed enhanced at lower energy due to the halo structure of this 1/2+ state of 13C
where the 2S 1/ 2 neutron orbit actually has the halo feature. The present result is in a good agreement with

Department of Physics, University of Tokyo

12

recent experimental data obtained in Tokyo Instituteof Technology by Nagai and his collaborators. 2) We
would like to emphasize that the direct neutron capture provides us with a precious and probably uniqueexperimental method to observe the halo structure in
excited states (of stable nuclei). The astrophysical implication of this state is quite significant for instancefor the inhomogeneous Big Bang models. The inverse
process, i.e., photo disintegration is discussed also foran example 11 Be which is known to have the neutron
halo in its anomalous ground state. A sharp but nonresonant peak near the threshold is obtained as anevidence of this neutron halo. This work has been
published. 3)
References
1) T. Otsuka et al.: Phys. Rev. Lett., 70, 1385 (1993).
2) T. Ohsaki et al.: Astrophys. J., 422 , 422 (1994).
3) T . Otsuka et al.: Phys. Rev., C49, R2289 (1994).

RIKEN Accel. Prog. Rep. 28 (1995)

Deformed Woods-Saxon Potential Approach to
the Structure of 11 Be
A. Muta* and T. Otsuka[Deformed Woods-Saxon potential, 11 Be, halo, unstable nuclei.]
The halo structure is explained as a tunneling effectin a loosely bound system of single-particle potential.
We consider the halo nucleus 11 Be , including its strong
deformation.
We first study the difference between the wave function in the Woods-Saxon potential and that in thesquare well potential, and find that the amplitude of
181/2 halo structure depends strongly on potential diffuseness. In other words , the amplitude of halo wave
function in the Woods-Saxon potential is larger thanthat in the square well potential. Hence the halo structure is a phenomenon sensitive not only to the loose
binding but also to the potential diffuseness. On theother hand, deformation effect on the halo amplitudeof 181/2 is small and this effect is more prominent in
the wave function of the inner part. We calculate (r2)
as a function of binding energy. For stable heavy nuclei, of which S(n) is more than 8 MeV, (r2) is mainly
determined inside the nucleus. On the other hand, fora halo orbit of unstable nuclei (r2) is influenced largelyby the density of the outer, i.e. , tunneling part.
Our calculation with the axially symmetric deformed
Woods-Saxon potential reproduces 181/2 halo structure of 11 Be quite well with a reasonable spectroscopic
factor (= 0.77)1) as shown in Fig. 12 ) and Fig. 2.3) Proton RMS radius, QQ , halo radius v(r 2 )halo, and S(p)are also reproduced well. Figure 2 shows, through theE1 excitation scheme, that the halo structure of 181/2
depends on the potential diffuseness. Figure 3 exhibits

the density distribution and one can see that the density distribution is strongly deformed. Furthermore, acluster structure is seen in Fig. 3.

o~~~~~~Lil~~~~

o

1

2

E ()leV)435Fig. 2. dB(E1)/dE for the photodisintegration of llBe
as a function of the excitation energy E. The solid(dot-dashed) line is obtained by the spherical (deformed) Woods-Saxon potential and is in agreementwith experimental data. The result obtained by asquare well potential (dashed line) does not reproduce
the experimental data.

5
E
tL

10- 1

0

L

-5

10-2

-10 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
-10 -50
5....a.....&...JI...I....L..L.I

10r (Fm)
Fig. 3. Matter density contour plot of 11 Be.
structure and super deformation are seen.

10-tl

Cluster

10-8 0L-"'--...a...&-"-"""'-....J5'-'---"'--"""'--1-'O---'~r (tm)

Fig. 1. Our calculation (solid line) using 181/2 wave function reproduces experimental data (dashed line) well.
Spectroscopic factor of S = 0.77 is taken. 1)

References
1) B. Zweiglinski et al.: Nucl. Phys., A315, 124 (1979).
2) M. Fukuda et al. : Phys. Lett., B268, 339 (1991).
3) T. Nakamura et al.: ibid., B331, 296 (1994).

Department of Physics, University of Tokyo

13

RIKEN Accel. Prog. Rep. 28 (1995)

Beta-decay of Neutron-rich Nuclei 17B and 19C
H. Kitagawa, A. Ozawa, and H. Sagawa[beta-decay, neutron-rich nuclei.]eRecently the beta-decay of neutron-rich nuclei 7B,
19N) with large isospins was measured at the
RIKEN Ring Cyclotron. 1) Nuclei of this mass region
are theoretically interesting because the isospin symmetry is expected to be broken, e.g. spin-parities of theground state of some of the mirror pairs are different
each other. The purpose of this work is to specify the
spin-parities which are unknown experimentally, andto investigate the configuration (especially the 81/2orbit in the sd-shell) of 19N through one-neutron stripping reaction to IBN + n.
The structure of the latter problem is as follows. By
a little consideration, the ground state of 19C shouldhave a positive parity. Due to the observed logft value,
this beta decay is assumed to be allowed one, then the
excited states of 19N are positive parity states, whichhave two holes in the p-shell. The observed negative
parity states of IBN must have one hole or three holes
in the p-shell. If the stripping of 19N to IBN + n isa single-step reaction , the I BN states concerning thisstripping should have three holes. Then the questionis why these observed three hole states are close to theground state that should be a one-hole state.
We calculate energy levels , logft values and branching ratios of beta-decays using the shell model with
the Millener-Kurath interaction. The model space isrestricted to p- and sd-shells. We consider only allowed
Gamow-Teller type beta-decay. Spectroscopic factors
are calculated in order to estimate the strength of the
stripping reaction of 19N to IBN + n. Though thisshell model interaction file is designed for the stateswith up to one hole in the p-shell, we will be able tomodify the interaction file in the shell model by fitting
the observed values of two and three hole states.
We show the results of calculations in Figs. 1, 2,
and Table 1. Energy difference between the groundstates of 17B and 17 C is well reproduced, although theexcited states (with a negative parity) of 17C is not reproduced so well. Though the calculated logft values
are well reproduced, the branching ratios are not reproduced. This would be because we cannot describe
correct energy levels of the excited states with this interaction file of the shell model, i.e. the model spaceis small for this kind of nuclei. The calculated valuesof logft and the branching ratios of the decay of 19C
seem well reproduced, but the energy differences between two levels which have different parities are not
reproduced. As the calculated values of the spectroscopic factors are quite small, these stripping reactions
are almost forbidden, different from the observed ones.
Decomposing each excited state into one and three hole
19C ,

14

states, we find these states are almost one hole states.
We need to make three hole components larger in order to reproduce the observed stripping scheme. Hencethe orbits in sd-shell should be lower and closer to thep-shell, breaking the isospin symmetry.
!17B 3/ 2- 23.002, 17

3/2- 22.68

B

expo

cal.

(3
.

1(3-

;

i

!

:

;

;
;

:

!

1

!

Ex

I

logft

IP

i
i Ex

! 3 /2 - 4.690 12.8137. 4 .737

- -; 5 /2 - 4.617 3.9627. 5.261
IP logft,: B'3.77 29 .67. 4.70
- _. 1/ 2 - 2. 803 83.0977. 4 .302!~:~~ ~:U~ t~73
0 + 073. 16C

0 + 0 . 168 1S - 1 7 3/2+ 0.000

C+ n

C

· 1.18 4 .87. 5.76

+ n 1 7 0.000
C

Fig. 1. Result of calculation for the decay of l7B.

! 19

1/ 2+ 18.542

c

cal.

expo

19

C

16.97

frr
; (3E
_ _·3/ 2 + 9
2II2477.l~S~= 1 1.2+ 8.73821.2857. 4 .872
3/ 2+ 8.579 26 .778% 4 .805

f73

2- 0 197

3fO · 127~
1- 0 · 106 - 6.348
2- 0:000 8 N + n! Ex

If! IORft
14.2% 4:61
6 .4920.6% 4 .55
6 .39 12.2% 4.80

~7.00
8:rnj_-

3 - f O.747~=

18

1- 0 .000

5 .32

N+n

-yg- 1/ 2 - 0.000-yg-(i / 2 , 3/ 2, 5/ 2) - 0.000

NN

Fig. 2. Result of calculation for the decay of 19C .

Table 1. Calculated spectroscopic factors of 19N to
IBN + n: (S~ / 2)2 x 10 5 .
I BNEex(MeV)19N

3/2 + (9.173)
1/2 + (8.738)
3/2 + (8.579)

12320.000 0.106 0.127 0.197
52
441

References
1) A. Ozawa et al.: to be published.

94
32
11

0
0
1

33
4
13

RIKEN Accel. Prog. Rep. 28 (1995)

Beta-decay of 17Ne and Isospin Symmetry
H. Kitagawa, A. Ozawa, and H. Sagawa[beta-decay, isospin symmetry.]
Breaking of isospin symmetry might play an important role to understand the structure of "halo" nuclei.
It is important to compare the mirror pairs (both themasses and the isospins are the same but z-componentsof the isospin are different.) in order to investigate theisospin symmetry breaking. Recently measured nuclear radii of the A = 17 isobars show asymmetry of
the isospin in this system. Since the nuclear radii reflect the spatial expansion of the nucleon (it consistsof matrix elements which contain expectation values ofr2 .), it is rather difficult to discuss the isospin asymmetry in a quantitative way. We can see this asymmetry easily if we use the beta-decay strength, because it
consists of matrix elements which contain expectation
values of r or 1.
The {3+ -decay of the ground state of 17Ne to the firstexcited state of 17F has been measured by Borge et al.
Since this state of 17F is very close to the one-proton
threshold, it is considered as a candidate of a proton"halo" state. With the value of beta-decay strength ofmirror pairs, the asymmetry coefficient is defined 1} as

If the isospin symmetry is conserved, the value of 8
must be zero.
Borge et a1. 2} listed the value of 8 for several mirror pairs with their result of 17F. In most of the pairs
the values of 8 are small positive numbers close to zero.
This is considered as the result of the expansion of neutron wave functions compared with the proton ones.
The value of 8 of A = 17 pair is exceptionally large
and negative. They concluded that this is due to theeffect of the "halo"-proton of 17F.
We investigated theoretically the {3+ -decays of 17Ne
to both the ground and the first excited states of 17F
by using the shell model for the configuration. The
Skyrme Hartree-Fock wave function calculated with
the SGn interaction is adopted for the single-particle
wave functions. Since the ground state of 17Ne is close
to the two-proton threshold, we considered this state
as a two-proton "halo" state similar to the neutron"halo" of 11 Li. Through the beta-decay strength, it ispossible to clarify the configuration of 17Ne.
We calculated the (3+ -decay matrix element using
the Gamow-Teller type operator for 17Ne(1/2-) tothe first excited state of 17F(1/2+), and the unique
first forbidden operator for 17Ne to the ground state of
17F(5/2+). Main contribution of single-particle matrix elements is P1/2 ---+ 81/2 for 17Ne ---+17 F(1/2+)
and P1/2 ---+ d S / 2 for 17Ne ---+17 F(5/2+). We assumed
the configuration of 17F is the same as that of 17 0 neglecting the proton- "halo" of the first excited state of
17F.
Table 1. Result of calculations for A = 17 system.
17Ne config. same as 17N 81/2 only d5 / 2 only
expo
-0.682-0.55(9)0.203
8(1/2+ )>1
not yet-0.026-0.3488(5/2+ )>1
not yet
43.4%
64.6%
0
Br(5/2+)We show the result of calculation in Table. 1. Threetypes of configurations of 17Ne are considered; thesame configuration as that of 17N, the configuration
restricting the sd-shell only to the 81/2-orbit or only
to the ds / 2-orbit. The latter two configurations breakthe isospin symmetry. For the beta-decay of 17Ne to
17 F (1/2 + ), we can reproduce the observed value if we
assume the 81/2-orbit. If we use these restrictions to
the 81/2-orbit for the configuration of the 5/2+ state,
the value of 8 of 17Ne to 17F(5/2+) is very large. Thisis due to a suppression of the single particle matrix
element of P1/2 ---+ d S / 2 ' Though this decay has notbeen measured yet, we can expect that the 81/2 levelis lower than the d S / 2 level and the isospin symmetry is
broken in this pair. The measurement of the (3+ -decayof 17Ne to the ground state of 17F is desired, because
we can verify this assumption by the observed value.

References
1) I. S. Towner: Nucl. PhY8., A216, 589 (1973).
2) M. J. G. Borge et al.: ibid., A490, 287 (1988); Phys.
Lett., B317, 25 (1993).

15

RIKEN Accel. Prog. Rep. 28 (1995)

Giant Resonances in Nuclei with Neutron Skin
M. Yokoyama,* T. Otsuka, H. Sagawa, and N. Fukunishi[Neutron-rich nuclei , giant quadrupole resonance, exotic nuclei.]
The quadrupole, octupole, and dipole giant resonances in various nuclei are investigated in terms of the
Hartree-Fock calculations and the random-phase ap-

100 , - - - , -- , - -------,--- , - - - - - , - - - ,20lJ ~~~~~~~~~-~~~=-~

o

10

1·5

E .);

(j'vleV)20

30

Fig. 1. B(E2) of 28 0 obtained by means of the random-phase approximation (RPA) using the Skyrme III
interaction. The peaks in the low energy region (5-18
MeV) are considered to be neutron-mode excitations.

Department of Physics, University of Tokyo

16

proximation (RPA) using the Skyrme interaction consistently.
It is seen in nuclei with neutron skin l ) that the average excitation energies are lowered from the standard
mass number dependence and that neutron-mode excitations, which consist almost only of neutron contributions, lie below the primary (isoscalar or isovector)
giant resonances. The neutron-mode excitations havelarge strength comparable with the primary giant resonances. It is also seen that the correlation energy issmall in the neutron-mode because the proton-neutroninteraction does not affect so much.
Proton-mode excitations can be seen in the protonrich nuclei, but they are not so remarkable as in theneutron-rich nuclei.

References
1) N. Fukunishi, T. Otsuka, and I. Tanihata: Phys. Rev. ,C48 , 1468 (1993).

RIKEN Accel. Prog. Rep. 28 (1995)

Transfer and Fusion Reactions of Unstable Nuclei
K.-H. Kim,* T. Otsuka, and M. Tohyama[Neutron skin, fusion reaction, transfer reaction.]
The transfer and fusion reactions are studied for reactions between a stable and an unstable nucleus withneutron skin, taking as examples the reactions 40Ca +16, 28 0. The two-dimensional time-dependent HartreeFock (TDHF) method is used. 1)
Figure 1 shows the impact-parameters as functionsof the center-of-mass energy E e .m . , for (a) 40Ca + 16 0
and (b )-( d) 40Ca + 28 0 reactions. The boundary between the fusion and other reactions is indicated by
the solid line in (a) and (b). These boundaries are indicated by the dashed-dotted lines in (c) and (d). In(c) and (d) , the boundary between the regions I and
II is shown by the solid lines. The region I of (c) is
the transfer of less than one neutron and that of (d) is
the transfer of less than one proton. The region II is
the transfer of more than one neutron (in the case of(c )) or proton (in the case of (d)), and III is the fusion
region. All lines are drawn connecting points where
calculations are carried out. The classical value of b isshown by the dashed line.
It is shown that, in 40Ca + 28 0 reactions, the nucleon transfer is enhanced enormously for both protons
and neutrons. However, the neutron skin does not enhance the fusion cross section contrary to the usual
expectation.

10

(a)

(b)

B
6

4
2

S0
~

~1+-+-<>++-i-t+++++++++t++++-+-++->-+t-<-i4-t+++++t+++-+-++->-++-I>++-i-+++++-t-:l

.0 10

6
4

III

2

100

200

o

100

200

300

E c .m . [MeV]Fig. 1. Impact-parameter b as a function of E c . m . for(a) 16 0 + 40Ca and (b)- (d) 28 0 + 40Ca reactions.

References
1) K. T. R. Davies and S. E. Koonin: Phys. Rev., C23,
2042 (1981).
2) N. Fukunishi, T. Otsuka, and I. Tanihata: ibid., C48,
1648 (1993).

Department of Physics, University of Tokyo
17

RIKEN Accel. Prog. Rep. 28 (1995)

Mass Dependent Parameter Set of the Relativistic Mean Field
Theory for Unstable Nuclei and Nuclear Matter
Y. Sugahara* and H. Toki
[Relativistic Mean Field, Unstable Nuclei.]
Recently, the unstable nuclear beam facilities areavailable in various laboratories in the world. Thesefacilities push forcefully the boundaries of known nuclei toward the nuclear drip lines. Many interesting
properties as neutron halo and neutron skin are foundat the neutron drip lines and many more are being expected to be found.1,2) Such information in turn provides strong constraint on the nuclear astrophysics, inparticular, the supernovae and neutron stars. It is thenan interesting project for theoreticians to work out atheory on unstable nuclei and nuclear matter. We needin this case large extrapolation, which is usually very
difficult and a careful strategy should be made to makethe theory reliable.
We consider "relativity" as a key word of successin describing the experimental data. Our strategy istherefore to choose the relativistic mean field (RMF)
theory as the phenomenological theory with several parameters, which should describe unstable nuclei andnuclear matter. The form of the RMF theory issuggested by the microscopic theory, the relativistic Brueckner Hartree-Fock (RBHF) theory, which isable to reproduce the saturation property of nuclear
matter. 3 ) The parameters of RMF are then obtainedby using the experimental data including the unstable
nuclei.

We tried first to get a single parameter set to describe all nuclei, but had to use two parameter sets forsatisfactory results; TM1 for heavy nuclei (Z ~ 20) andTM2 for light nuclei (Z ::; 20).4) We, therefore, decide
to include mass dependence to all the coupling constants to get a parameter set for nuclei in all the mass
region. The parameter set is called TMA. We show
the binding energies for the proton magic nuclei as afunction of the mass number in Fig. 1, in which the results of NL1 and the experimental data are plotted ascomparison. We show also the proton and the neutronradii in Fig. 2.

6.5

J::::o~~! t /..
2.5

~

Pb

I

- 7.5

- 6.5
5.5
4.5

Zr

3.5
~
. Ca
0.5 .......................
1.........""'1................
1 ..................
1...............,,1..............., 2.5
o 50 100 150 200 250 300
1.5

A
9.5

I

8.5

;>
0

~

7.5

~

6.5

r..Ll

5.5

c

I

~

f ' \. ~I--

4.5 ..........................
1............................................................................
o 50 100 150 200 250 300

A
Fig. 1. Binding energies of the proton magic nuclei asa function of the mass number. The results of TMA
are denoted by solid curves and those of NLI by dottedcurves and they are compared with the experimental
values denoted by circles.

Department of Physics, Tokyo Metropolitan University

18

Fig. 2. Proton and neutron radii of the proton magic
nuclei. The notations are the same as Fig. 1. The experimental values of proton radii are denoted by circles
and those of neutron radii by the triangles.

We calculate then the profile of neutron star as afunction of the central density. The critical mass ofthe neutron star is reduced to about twice the mass ofthe sun for TMA. The proton fraction is found pretty
large even for the case of TMA, where the symmetryenergy at the saturation density is moderate.
References
1) 1. Tanihata et al.: Phys. Rev. Lett. , 55, 2676 (1985).
2) 1. Tanihata et al.: Phys. Lett., B289 , 261 (1992).
3) R. Brockmann and R. Machleidt: Phys. Rev., C42,
1965 (1990).
4) Y. Sugahara and H. Toki: Nucl. Phys., A579 , 557(1994) .

RIKEN Accel. Prog. Rep. 28 (1995)

Relativistic Mean Field Theory for Unstable Nuclei and
the Birth of Neutron Stars
K. Sumiyoshi, D. Hirata, Y. Sugahara,* H. Suzuki, and H. Toki
[relativistic mean field theory, unstable nuclei, neutron stars.]
The recent advance in unstable nuclear beam experiments provides us with new knowledge on unstable
nuclei away from the stability line. 1) Such extensive
studies on unstable nuclei have also a potential to provide us with valuable information on the dense matter
under the extreme conditions such as a neutron richenvironment in neutron stars. Hence, it is important
to construct a many body framework, which is reliable
even for unstable nuclei, and apply the same framework to provide the equation of state (EOS), which isessential to clarify the mechanism of supernova explosions and the evolution of neutron stars.
We study the properties of unstable nuclei awayfrom stability and the equation of state (EOS) for neutron stars and supernovae in the relativistic mean field(RMF) theory.2-7) The lagrangian with the non-linear(7-W terms of the RMF theory5) is motivated by the recent success of the relativistic Brueckner Hartree Focktheory. B) We use the parameter set TMI determined by
the fitting to the experimental data of nuclei including unstable ones. The RMF theory thus constructed
reproduces successfully the binding energy of many nuclei other than used in the fitting. 2- 5 ). We show in Fig. 1 the calculated results of the rootmean-square radii of the distribution of protons andneutrons of Sn isotopes in the RMF theory with TMl.
We also show the results of the Skyrme Hartree-Fockcalculations 4 ) with the parameter set SIn for comparisons. The results of the RMF theory are in excellent
agreement with experimental data for the radii for protons. The radii for neutrons are significantly different

5.5

8~ 5.0

between the two calculations depending on the symmetry energy. This difference in the neutron rich region
will be examined in more detail by future experimental
studies.
We then apply the EOS calculated in the same RMF
theory6,7) to the numerical simulation of the coolingof a protoneutron star just born in the supernova
explosion. 9 ) We show in Fig. 2 the calculated time profile of the mean energy of neutrinos emitted from theprotoneutron star during the cooling. Here we compare it with the case with the EOS having the reduced
symmetry energy.

5

10

15

20

time [sec]Fig. 2. The time profiles of the mean energy of supernova
neutrinos in the two cases with different symmetry energies.
We found that the symmetry energy, which is essential to describe unstable nuclei, influences the thermal
evolution of protoneutron stars and supernova neutrinos emitted in the supernova explosion. It would beinteresting if we could examine the properties of supernova neutrinos by comparisons with the detectionof the neutrino burst in future supernova explosions interms of the EOS constrained by the unstable nuclei.

~

4.5

60

80

100

120

N

Fig. 1. The root- mean-square radii R of Sn isotopes asa function of the neutron number. The experimental
data are shown by dots.
Department of Physics, Tokyo Metropolitan University

References
1) I. Tanihata et al.: Phys. Rev. Lett., 55 , 2676 (1985).
2) D. Hirata et al.: Phys. Rev., C44, 1467 (1991).
3) D. Hirata et al. : Phys. Lett., B314, 168 (1993).
4) K. Sumiyoshi et al.: Nucl. Phys. , A552, 437 (1993).
5) Y. Sugahara et al.: ibid., A579, 557 (1994).
6) K. Sumiyoshi et al.: Astrophys. J., 422, 700 (1994).
7) K. Sumiyoshi et al.: Nucl. Phys., A58t, 725 (1995).
8) R. Brockmann et al.: Phys. Rev., C42, 1965 (1990).
9) K. Sumiyoshi et al.: submitted to Astron. Astrophys.
19

RIKEN Accel. Prog. Rep. 28 (1995)

Study of the Triaxial Deformation in the Relativistic
Mean Field Theory
D. Hirata, K. Sumiyoshi, B. V. Carlson, H. Toki, and I. Tanihata[Nuclear Structure, binding energy, gamma deformation, relativistic mean field theory.]
The use of the radioative beam facilities has allowed
us to study the nuclear structure of nuclei far fromthe stability line.1 ,2) The studies of exotic nuclei display a large diversity of phenomena which could not
be observed in the stable ones. 3 )The relativistic theories have been extensively applied in the last few years to nuclei and nuclear
matter with remarkable success. The description of
the ground state properties of the stable and unstable nuclei including the axial deformation, using
the relativistic mean field theory (RMF) is extremely
successful. 4-6)
Recently, the RMF theory has been applied to study
the ground state properties of unst able nuclei suchas Sr, Xe, Cs and Ba isotopes, under the axial symmetry assumption. 6,7) The results of the calculat ion
were in good agreement with the experimental data
for the neutron rich nuclei. However, in the protonrich side, the description was not as good and it was
attributed to a transitional character in that region. 3 )The non-relativistic calculations seem able to describe
these isotopes when the triaxial deformation assumption is taken.
Recently, the RMF theory with the axial symmetry
assumption, has been also applied to study the groundstate properties of very rich neutron sulfur nuclei. 8)
The results of the RMF calculation were comparedwith those obtained from the non-relativistic HartreeFock (HF) with Skyrme forces. However, the HF calculations were performed under the triaxial symmetry.
It is therefore a challenge to extend the RMF theory to
non-axially-symmetric configurations, that is the triaxial deformation, and to apply it to these nuclei.
The extension of the RMF theory from the axial
symmetry to non-axially symmetric configurations israther difficult. In order to simplify the calculations,
we expanded the meson fields and the Dirac spinors
in deformed basis. With those expansions, the Diracequations were reduced to a complex hermitian matrix diagonalization problem and the meson fields toan inhomogeneous set of linear equations.
Due to the size of memory and cpu limit we had
to truncate the expansion at N = 8 major shells forfermions and bosons. With this procedure we had torestrict our calculations to light systems.
Here, we present the results of the RMF theory withthe triaxial symmetry for the 160, 24Mg and 46- 48 S using the TMI parameter set. 9 ) We performed constraint
calculations with the quadrupole moments in order toobtain the energy surface on the (f3,'"Y) plane. The deformation parameters f3 and '"Y were determined fromthe expectation values of the intrinsic quadrupole mo20

ments (Qj.L) = (r2Y2j.L) , where

f3 =

3:

2

(1.2A ' / )2J(QO)2 + (Q2)2 and'Y =v'2~~:~:.

Figure 1 shows the energy surfaces of these nuclei inthe (f3(y ) plane, where '"Y runs from 0° to 60°. The horizontal axis corresponds to the prolate solution while'"Y = 60° corresponds to the oblate solution.

·
L

L<i>

24 Mg

160

•

y;O'

Mj£M~'.

0.0

0.2{!c05Y'

0.4)'"D '

0.0

0.2

0.4

{!cO$Y

Fig. 1. The energy surfaces for 160, 24Mg and 46- 488 in
the plane. (/3,'"'(). The absolute minimum of the binding
energy is denoted by a black dot.

In summary, we have applied the RMF theory under
the triaxial symmetry on 16 0 and 24Mg nuclei in orderto test the performace of the code for spherical andaxial deformed nuclei. The results obtained with the
new code are quite similar to those obtained using theaxial and spherical codes and are in good agreementwith the experimental data of charge rms radii , binding
energies, and the quadrupole moment of Mg.
We have also performed the RMF theory calculations with the same assumption as the HF8 for the veryrich 46- 48 8 isotopes and found that both are gamma
soft deformed. The RMF calculations give '"Y = 2.8°
for 46S and '"Y = 28.7° for 48 8 while the HF calculation
gives '"Y = 10° for 48 8.
References
1) I. Tanihata et al.: Phys. Rev. Lett. , 55, 2676 (1985).
2) I. Tanihata et al. : Phys. Lett., B289, 261 (1992).
3) J. H. Hamilton: Treatise on Heavy-Ion Science, Vol. 8,
ed. D. A. Bromley, Plenum, New York, p. 3 (1989) .
4) R . Brockmann and R. Machleidt: Phys. Rev. , C42 ,1965 (1990).
5) Y. K . Gambhir et al.: Ann. Phys., (NY) 198, 132(1990).
6) H. Toki et al.: Nucl. Phys. , A524, 633 (1991); D . Hirata
et al.: Phys. Rev. , C44, 1467 (1991); D. Hirata et al.:Phys. Lett. , B314, 168 (1993).
7) D. Hirata et al.: submitted to Nuc. Phys.
8) T. R. Werner et al.: Phys. Lett., B333, 303 (1994).
9) Y. Sugahara and H. Toki: Nucl. Phys., A579, 557(1994).

RIKEN Accel. Prog. Rep. 28 (1995)

Effective Interaction in Asymmetric Nuclear Matter
N. Fukunishi[Asymmetric nuclear matter.]
Properties of asymmetric nuclear matter play crucial roles in many branches of physics. Asymmetricnuclear matter is a virtual system which is composed ofdifferent number of protons and neutrons without the
Coulomb interaction. Bulk properties of neutron-richnuclei strongly relate to asymmetric nuclear matter.
The equation of state for asymmetric nuclear matteris also important in the physics of neutron stars1) andtype-II supernova. 2 )We employ the non-relativistic Brueckner-HartreeFock (NRBHF) approach. It is well known that the
NRBHF theory does not reproduce correct saturation properties for symmetric nuclear matter. Thus,
some other approaches, for examples, the relativistic Brueckner-Hartree-Fock (RBHF) theory, have been
proposed. However, studies of asymmetric nuclear
matter in the NRBHF theory is meaningful becauseof the following three reasons.
(1) We are mainly interested in how properties of amany-nucleon system change according to the asymmetry ratio a = PN
PN +-PP . Note that about 90% of thePPpotential energy is reproduced in the NRBHF theory.
(2) More elaborated calculation within the nonrelativistic framework given by Jiang et al. ,3) improves
the discrepancy between theories and experiments.
(3) The predicted properties of asymmetric nuclear
matter, for example, the density dependence of thesymmetry energy, are different between the NRBHF
and the RBHF theories. 4 )In the NRBHF theory, the G-matrix interaction,
which is an effective interaction in the nuclear media,
is calculated from the realistic nuclear forces as follows,

G(w) = V + V

QJi G(w).
w- 0
V implies a nuclear force. The Reid Soft Core interaction is used in this calculation. Q means the Pauli
operator which is the origin of the density-dependenceof the G-matrix interaction. w is the starting energy, i.e. , the energy of the two nucleons in asymmetric nuclear matter. The starting energy is determined
self-consistently in this framework and may change inasymmetric nuclear matter compared with the symmetric case. Ho is an energy of the intermediate states.
We employ the BBP prescription5 ) for Ho. Similar calculations have been performed. 6 , 7) The main differenceis that the present calculation treats the Pauli operator exactly. We calculated various quantities in thisframework. We find that the correct treatment of thePauli operator changes properties of asymmetric nuclear matter little.

We further examine the a-dependence of the effective interaction (G-matrix interaction) . Figure 1 shows
the G-matrix interaction for the 381 channel in which
the strongest a-dependence is seen. The G-matrix interactions are illustrated with the solid line (a = 0)
and the dashed line (a = 0.32). Note that a =corresponds to N = 2Z. (N is a neutron number and Z
is a proton number.) Near the saturation density, thedensity-dependence of the G-matrix is very weak. Thisis one of the origins of this weak a-dependence. The
starting energy dependence of the G-matrix is rather
strong for the 3S1 channel. For a = 0.32, the energyof a proton or a neutron changes significantly. However, the starting energy which is a sum of the proton
and the neutron energy changes little. This is anotherorigin of the observed weak a-dependence. This calculation implies that the G-matrix interaction calculated
in symmetric nuclear matter can be used for the asymmetric case.

l

o
-2600
-5000

!

-7500

-10000-12500

0.5

0 .75

1.25

1.5

k(fm- I )Fig.

1. G-matrix interactions for the 3 S1 channel (kF= 1.45 fm -1). The solid line shows the symmetric caseand the dashes line indicates the asymmetric (0: = 0.32)
case.

References
1) J. Nemeth and D. W . L. Sprung: Phys. Rev., 116, 1496
(1968); N. C. Chao, J. W. Clark, and C. H. Yang: Nucl.
Phys., A119, 320 (1972).
2) E. Baron, J. Cooperstein, and S. Kahana: Phys. Rev.
Lett. , 55, 126 (1985).
3) M. F. Jiang, R. Machleidt, and T. T. S. Kuo: Phys.
Rev., C41, 2346 (1990).
4) H. Huber, F. Weber, and M. K. Weigel: Phys. Lett.,
B311, 485 (1993).
5) H. A. Bethe, B. H. Brandow, and A. G. Petschek: Phys.
Rev., 129, 225 (1963).
6) 1. Bombaci and U. Lombardo: ibid., C44, 1892 (1991).
7) H. Q. Song, Z. X. Wang, and T. T. S. Kuo: ibid., C46,
1788 (1992).

21

RIKEN Accel. Prog. Rep. 28 (1995)

Stationary Solution of Time Dependent Density
Matrix Formalism
M. Tohyama[density matrix formalism, ground state correlations, Lipkin model.]We have recently reported realistic calculations forthe damping of giant resonances!) and for low-energy
heavy-ion collisions,2) based on the time dependent
density matrix theory (TDDM). Although the obtained results are quite encouraging, these numericalcalculations contain inconsistency in the treatment of
the ground state: the Hartree-Fock (HF) ground state,
which clearly is not a stationary solution of TDDM, isused as the initial ground state. An attempt to find astationary solution of TDDM was made in Ref. 3 but
was not quite successful. In this report we demonstratethat a better stationary solution of TDDM can be obtained through an adiabatic treatment of two-body interactions. We use the Lipkin model hamiltonian 4 )which consists of N fermions occupying two N-folddegenerate levels with energies f./2 and -f./2, respectively. The states in the upper level are labeled byquantum number p = 1,2, ... N, while those in thelower level are labeled by -po We solve the TDDM
equations of motion for the Lipkin model, starting fromthe HF ground state and adiabatically turning on the
two-body interaction:

V(t) = V(l - e- t / T ).

In Fig. 1 the occupation probability of the upper leveln p , the two-body correlation matrix C_P_P'pp' and thetotal energy E are shown as a function of time for an
N = 4 system with IVl/f. = 0.3. Each of n p , C_p _ p'PP'
and E approaches a constant value at large t. We
found that as long as 7 » hi f., the solution at large t
becomes stationary and does not depend on 7. 5 ) The
obtained results of E for various values of IVII f. arecompared with the exact ones in Fig. 2. The totalenergy E in TDDM has the IVl/f. dependence similar
to the exact one.

·1.9

·2.0 ----...:-.......... .. ...................•............ -..... -..... ... .

~ ·2.1
·2.2
·2.3

(1)
·2.4 ""--_"--_L......---l'-----'_---L_----'---=I

0.00

0.05

0.10

0.15

0.20

0.25

0.30

IVllt
0.20 ~--'------'----'r----,-----= · 1.8

Fig. 2. Total energy as a function of IVI /E for the N = 4
system. Solid line denotes the results of the TDDM calculation and dotted line the exact solution. Dot-dashedline indicates the HF result.

·1.9

·2.0

/n

·2.1

p

~
(I"l

·2.2
·2.3
· 2.4
4

5

tl't

Fig. 1. Time evolution of E, np and C_P_P' pp' in TDDM
for an N = 4 system.

22

References
1) M. Gong and M. Tohyama: Z. Phys., A335, 153 (1990).
2) M. Gong, M. Tohyama, and J. Randrup: ibid. , p. 331.
3) H. J. Lipkin, N. Meshkov, and A. J. Glick: Nucl. Phys.,
62, 188 (1965).
4) M. Tohyama, P. Schuck, and S. J. Wang: Z. Phys.,A339, 341 (1991).
5) M. Tohyama: Prog. Theor. Phys., 92, L905 (1994).

RIKEN Accel. Prog. Rep. 28 (1995)

Strength for Isoscalar Modes in Diabatic Picture
S. Yamaji and H. Hofmann*[Large Scale Collective Motion, Linear Response Theory, Diabatic Motion.]
We studied the collective response function as afunction of the excitation energy for typical isoscalarmodes. 1) We found that the strength function exhibits
the usual low energy and giant resonance peaks at low
temperatures whereas all the strength is concentrated
in a low energy mode at temperatures higher than atemperature of around 1.5 MeV. Thus the vibrational
inertia of slow motion turns into that of irrotational
flow at high temperatures. According to the study inRef. 2 this is largely due to the fact that the vibrations
looked at are the ones about thermal equilibrium intrue sense. It is described by the many-particle manyhole configurations which come into play through thecou pIing constant k expressed by2_ k_ 1 =8 E(Q , S)
(0)
8Q2
+X ,

where E( Q, S) is the lowest possible energy specified
by the collective variable Q and the entropy S in thequasi-static picture, and X(O) is the static response. 1)
In t his sense the E(Q , S) represents what in nuclear
physics often has been associated to "adiabatic dynamics" .
Still according to Ref. 2 completely different behaviour is to be expected if the coupling constantis evaluated in the "diabatic" picture with all occupation numbers frozen. For vibrations of this typethe previous formulas in Ref. 1 can be taken over.
The only change necessary is to replace k by a diabatic coupling constant kdi whose value is given by
the above expression with the quasi-static energy being replaced by the diabatic one Edi(Q,S). The cor-

responding coupling constant kdi stays constant withexcitation, rather than decreases as in the case of "adiabatic" motion (see Fig. 5 of Ref. 2).
In Fig. 1 we present a numerical computation, again
for the same situation as in Ref. 1, but with k replacedby k di . No shift of strength is seen. Only the giant peaks get broader at higher temperatures. Thisis traced back to the increasing single particle widthwith temperature.
Quadrupole Vibration(Diabatic) of 208pb

20000

T", 0.5 MeV

15000

5000

o

5

",(MeV)

10

15

Fig. 1. Strength distribution for diabatic quadrupole vibrations.

References
1) H. Hofmann, S. Yamaji, and A. S. Jensen: Phys. Lett.,
B286, 1 (1992).
2) D. Kiderlen, H. Hofmann, and F. A. Ivanyuk: Nucl.
Phys., A550, 473 (1992).

Department of Physics, Technical University of Munich,Germany

23

RIKEN Accel. Prog. Rep. 28 (1995)

Possible Interpretation of Extremely Low Energy
Odd Spin States
T. Horibata and N. Onishi[r-deformation, Tilted rotation, Wobbling motion.]
The dynamics of nuclear rotation including precession and wobbling is studied in order to make clear
the mechanism dominating collective motions in nuclei, especially in the ,-unstable region, e.g., isotopesof tungsten or osmium. The wobbling motion is associated with triaxiality of nuclear deformation, and hence
is likely to be strongly coupled with the fluctuation of,-degrees of freedom. In fact, classical motions for a
macroscopic model of the ,-soft rotor exhibit remarkable dynamics interweaving the ,-vibration and thewobbling motion, and are shown to possess a typicalfeature of nonlinear mechanical systems. I) We investigated how these mechanisms manifest themselves in
the collective state in the microscopic nuclear system.
Mikhailov and Janssen 2) suggested that the nuclear wobbling motion occurs as a result of Coriolis
interaction pushing down odd spin states of the ,vibrational band till it becomes close to the even spin
yrast line. Following this idea, Matsuzaki discussed
possible exsistence of the motion in 182 Os based on the
RPA calculation. 3 ) However those works are restrictedwithin a linear vibration theory of the wobbling motion
being slightly off from the stationary rotation along theprincipal axis of quadrupole deformation.
Recently we proceed a self-consistent threedimensional cranking calculation,4) and report the exsistence of tilted axis rotating states (TAR-states) inthe crossing yrast band of the nucleus. 5 ) Figure 1 showsenergy minima in the three dimensional potential surface for 1820s. Based on the symmetry properties,
there are two minimum points at the mirror image
positions with respect to the equator on the prime
meridian. These minima represent the axes of stationary rotation in which wavefunction the symmetry ofsignature is broken down. The tunneling back andforth motion between the two points recovers a definite signature. Two solutions are obtained from the
double-well model. The lowest solution corresponds to
the Gerade state which is an even signature state andthe other one is the next lowest Ungerade state which
is an odd signature state. Namely,'lis =i:2

24

f'f,(4))WT(4>)d4> U'f,(-4»= ±f'f,(4))). (1)Fig. 1. Energy contour map of J = 15 sphere.

Therefore the Gerade and Ungerade solutions represent even and odd angular momentum yrast states,
respectively. The energy defference gives the signature
splitting. This result may have a different feature incontrast with the prediction by Mikhailov and Janssen.
The existence of TAR solutions in yrast implies a possible new interpretation for the backbending phenomena
in nuclei of ,-unstable region, and serves an explanation of abnormal spectra observed in the the odd-spin
yrast-band in 1820s nucleus.
References
1) N. Onishi and D . Chang: Nucl. Phys. , A557, 301c
(1993).
2) I. N. Mikhailov and D. Janssen: Phys. Lett. , 72B, 303(1978).
3) M. Matsuzaki: Nucl. Phys. , A509 , 269 (1990).
4) A. K. Kerman and N. Onishi: ibid. , A361, 179 (1981);
N. Onishi: ibid. , A456 , 279 (1986).
5) T. Horibata and N. Onishi: Phys. Lett., B325, 283(1994); RIKEN Accel: Prog. Rep., 27, 14 (1993).

RIKEN Accel. Prog. Rep. 28 (1995)

The Ml Ttransitions and the New SU(3)in Superdeformed Nuclei
K. Sugawara-Tanabe, A. Arima, and N. Yoshida[M1 transitions, Superdeformation.]
We have already proposed the idea that the quantization of alignment in superdeformation comes fromthe parity doublet (P-D) levels l ) by the addition of
the pure "s" instead of the pseudo-spin "s". The P -D
levels are the two different parity single particle levels
with the asymptotic quantum number representation,[N,N,OH and [N - 1,N - 2, 1H, which are almost
degenerated in a deformed axially symmetric Nilsson
potential around superdeformation, and the Fermi surface for Z = 66 or 80 and N = 86 or 112 locates near
this degeneracy. Both of the P-D levels belong to thesame supershell with Nsh = N. We found that the
L - S coupling scheme is restored in superdeformation not only for the P-D levels but also for all theother levels belonging to the same N sh . This is causedby the strong coupling between the spin-orbit partners
with small R. like p1/2 and p3/2, which influences thelarge R. spin-orbit partners through the strong coupling
among the same spin-orbit coupled R.±2Ievels. We also
found that the effect of the unique-parity level, which
is not taken into account in the pseudo-spin scheme,
should not be neglected in superdeformed states. A
good physical quantity to check this idea is the M1
transision rate, as M1 operator is proportional to spin.
The M1 transition rate between the superdeformed
bands in 193Hg was observed and the gK factor was

extrapolated. 2) We calculated the M1 transition rate
and found the several candidate levels which explain
this experimental value of gK factor. Since we canneglect the effect of the spin-orbit interaction at superdeformation, we can construct a new SU(3) group
introducing the new boson operators in the z-axis. We
constructed 8 generators that fulfill the commutation
relation of SU(3) from the byproduct of this set ofboson operators in analogy to Elliot's SU(3) mode1. 3)This new SU(3) group corresponds to the space neglecting !:::,. Nsh f= 0 in contrast to Elliot's SU(3) where!:::,. N f= 0 is neglected. In Nsh both positive and negative parity levels are degenerated and even Nsh andNsh + 1 have the same Casimir operator, and subsequently the new SU(3) is duplicate. Similarly we canconstruct a new SU(3) scheme in the hyperdeformation and the superdeformation in 132Ce region. In theformer case SU(3) is triplicate and in the latter case it
has six-degeneracy.

References
1) K. Sugawara-Tanabe, A. Arima, and N. Yoshida: Nucl.
Phys., A570, 291c (1994).
2) M. J. Joyce et al.: Phys. Rev. Lett., 71, 2176 (1993).
3) J. P. Elliot: Pmc. Roy. Soc. W, A245, 128;562 (1958).

25

RIKEN Accel. Prog. Rep. 28 (1995)

Systematics of Alpha Q-values: Alpha Decay
Life Times of Unstable Nuclei
H. Sato[a-decay Life.]
In the previous work,l) we found that the a decay
half life in a wide region of even-even nuclei can be
reproducible with the method employed by Arima andYoshida,2) if a reliable theoretical S-factor and a realistic potential for the relative motion of the a and residual nucleus are taken into account. Here we extend
the study to the systematics of a decay half lives of all
the a decayable nuclei by applying the same method
to the unstable nuclear system with the employmentof a double folding potential for the relative motionof the a and residual nucleus, whose potential depth isobtained by solving the eigenvalue problem for the a Q
value given by Tachibana, Uno, Yamada, and Yamada

mass formula. 3 ) The density distributions of unstable
nucleus are evaluated with a DDHF type variational
calculation. Employing the node quantum number Nrconsistent with the single particle level scheme of a simple shell model, we calculate the a decay half life T 1/2
by In211,jr for all the a decayable nuclei by assuming
the angular momentum L = 0, and summarize those in
Fig. 1 as a function of Z and N. Figure 1 corresponds
to the contour plots of the logarithms loglQ(T l / 2) atevery 2 order difference in the a decay half life times
T 1/2 in units of seconds. The dark area at the borderin the contour plot of Fig. 1 shows the degeneracy ofcontour lines due to a drastic change of decay half life
Q

32
28
o

co

24
20

oz
o
et:

16
<0

f-.

12

A.

4

o
-4
-8
-12

NEUTRON #Fig. 1. The contour plots of the logIQ(T 1 / 2 ) of Q:' decay half lives with S = 1 in units of seconds.

times. The cliffs can be seen at the border (i.e. the adrip line in nuclear chart) and also at magic numbers.
The a decay half life times are drastically changed atmagic numbers N = 50, 82, and 126. We compare theresults with the (3 deacy half life times predicted.
The author would like to thank Professor M. Ishihara for his encouragement.

26

References
1) H. Sato: RIKEN Accel. Prog. Rep., 27, 18 (1993).
2) A. Arima and S. Yoshida: Phys. Lett., B40, 15 (1974);
Nucl. Phys., A219, 475 (1974).
3) T. Tachibana, M. Uno, M. Yamada, and S. Yamada:At. Data Nucl. Data Tables, 39, 251 (1988).

RIKEN Accel. Prog. Rep. 28 (1995)

Shell Model on a Random Gaussian Basis
K. Varga[shell model, alpha decay, stochastic variational model.]A realistic study of alpha decay or cluster-decay process demands a reliable description of the motion of
nucleons at the nuclear surface. The representation ofa decaying state in the shell model requires handlingof huge bases that is often beyond the capability of thecomputers. 1) This problem was recently circumvented
by complementing the shell model with a cluster-modelbasis. 2,3) This cluster-configuration shell model, however, is difficult to apply. We therefore developed a
new model, which is closer to the conventional shellmodel but in practical applications may be superior.
The new model 4 } is essentially a shell model, in
which the valence orbits are replaced by combinationsof Gaussian functions of different size parameters, withexact Pauli projection off the core orbits. These gaussians are more flexible than the harmonic oscillator
single-particle (s.p.) functions because their width parameters are free. A variational background can guarantee that they will be automatically chosen so as tosuit to the problem considered. In particular, the gaussians can produce a more realistic fall-off in the surface , which is important for the description of decay
processes. Moreover, in the interior the gaussians areable to simulate the effects of several oscillator shells.
Note that the Pauli projection provides the gaussians
with some, say no , nodes, so that n gaussians in the
expansion of a s.p. function will involve s.p. orbits ofno," . ,no + n - 1 nodes. In spite of the , inclusion ofsuch high-lying shells, the problem may still remain
tractable if the basis elements are carefully selected.
We admit states in the basis depending on their contribution to the g.s. energy. This method of choosing
random states as candidates for the basis is called the"stochastic variational method" .5)
To test this new model we applied for the descriptionof the alpha decay of 212po and compared the results to
those of the previous model. The energy of the decay
has been reproduced succesfully, the absolute decay
width is slightly underestimated.
In summary, with the help of the stochastic variational method, a flexible shell-model wave function has
been constructed for the ground state of 212po using

combinations of Gaussian functions as single particle
orbits. The present model gives nearly as good a result
for the alpha decay width as our former model, whichis sharpened just to describe the alpha decay. The
chief merit of the model presented here is its technicalsimplicity, which makes it easily applicable to otheralpha or even to heavy-cluster decays.
0.14
0. 12
0.10
~

:::-I

.....E""---'!

0.08
0.06
0.04

0.02
.........
I........,
0'1 0,00

-0.02
-0.04
0

2

4

r

6

8

(fm)

10

'2

Fig. 1. The formation amplitude as a function of the
distance between the alpha particle and the daughter
nucleus. The solid line represents the cluster configuration shell model,2 ,3) and the dashed line the result of
the present model. 4 }References
1) I. Tonozuka and A. Arima: Nucl. Phys., A323, 45(1979) .
2) K. Varga, R. G. Lovas, and R. J. Liotta: Phys. Rev.
Lett., 69, 37 (1992).
3) K. Varga, R. G. Lovas, and R. J. Liotta: Nucl. Phys.,
A550, 421 (1992).
4) K. Varga and R. J. Liotta: Phys. Rev., C50, R1292(1994).
5) K. Varga, Y. Suzuki, and R. G. Lovas: Nucl. Phys.,
A571, 447 (1994).

27

RIKEN Accel. Prog. Rep. 28 (1995):E-Hypernuclear Production Spectra on a 9Be Target
T. Harada and H. Kitagawa[ L:-hypernuclei, narrow width, (K- ,11"-) reaction, DWIA, shell-model.]The aim of this study is to understand theoreticallythe L:-hypernuclear production by the 9Be(K- ,11"-) reaction with the distorted-wave impulse approximation(DWIA) . In this note, we discuss the structure of ~Be­
hypernucleus within the shell-model approach, in order to determine the characteristic behavior of a L:hyperon in light nuclei.
The discovery of the long-lived L:-hypernuclear state(T ::; 8 MeV) by the 9Be(K- ,11"-) reactions at CERN
made us excited about a narrow width puzzle, 1) because its L:N -+ AN conversion width was expected to
be r rv25 MeV in nuclear matter. 2) Many efforts weremade so as to understand narrow peaks. However,there had been such poor statistics in this data that we
could not solve the puzzle. Recently, L:-hypernuclear
spectra measurements on a 9Be target at BNL werereported in better statistics3 ): There appears a broad(not narrow) peak at BEorv12 MeV in the continuum
regions. In order to investigate theoretically the structure of ~Be-hypernucleus , we construct the nucleus-~
optical potential by the folding model. The opticalpotential is obtained as

UJ(R) = ([pIO(8 Z) 0 ~l:1

efliEN(r - W~ I)) 1[p'J:(8 Z') ~{)
R; p

R

0

where 4>Ic(8Z) is the Cohen-Kurath wave function of
the A = 8 core-nucleus and R is the relative coordinate between the core-nucleus and the L:- hyperon.
eff tEN (r; p) denotes the effective ~N interaction withdensity (p) dependence, which is derived from theBrueckner g-matrix calculation with Sigma-nucleon
absorptive potential (SAP)4) in a nuclear medium.
Note that the real part of the optical potential is shallow and has a peculiar shape with a repulsive core near
the nuclear center.
Let's consider the L:-hypernuclear inclusive 11" - spectrum in 9Be(K- ,11"- ) reaction.
We calculate thedouble-differential cross section within the DWIA
framework by using the Green function method. 5 )Figure 1 displays the calculated spectrum at PK - =720 MeV Ic within L: single-particle description by theshell-model approach, together with the experimental data at CERN. 1) We find two peaks in the spectrum: The peak near BEOrv7 MeV, above the L: 0 _emission threshold, comes from continuum states of
8B(T = 0; J7T = 0+ , 2+) 0 L:°. The second peak near
BEo rv20 MeV also originates from main configurationsof 8Li- 8 B- 8 Be(T = 1; J7T = 2+, 1+, 3+) and L:+ _L: 0 _
L: - in the continuum states. The calculated spectrum
28

seems to be similar to the earlier CERN data, rather
than the recent BNL data.

10
10

I

0
-10 1

-10

1 B~ (MeV)

1-1--+----.,1 I¥ (MeV)~e(K-,1T-)
720MeV/c (Odeg.)

260

280

300

MHY - M", (MeV)

Fig. 1. The calculated 7r - spectrum by the 9Be(K - ,71" - )reaction at PK- = 720 MeV Ie is shown together withthe experimental data at CERN . 1 )On the other hand, performing the microscopic cluster calculation6 ) of a+3N+L: in ~Be (~Li) , we showedthat there appears a cluster phenomenon of a+~He(a+~H) as if it were the well-known di-molecular a+a
struct ure of the 8Be ground state. It is far from thestructure of ~Be (~Li) , where a A-hyperon plays a roleof glue between a and 3N due to no 1I"-P exchange in the
AN interaction. It should be noted that no clustering
effect is taken into account in this shell-model calculation. Thus it is suggested that there should exist acluster configuration of a+~He+n in ~Be. We mightobtain a large enhancement near BEOrv12 MeV in the
9Be(K- ,11"-) reaction if such a cluster phenomenon isswitched on.
In conclusion, we cannot reproduce the 9Be(K- ,11" - )spectrum in the recent BNL data within the shellmodel approach. The spectra shape might provide sovaluable information for us to determine the behaviorof the L:- hyperon in light nuclei.
References
1) R. Bertini et al.: Phys. Lett. , B90, 375 (1980) .
2) C. B. Dover, D . J . Millener, and A. Gal: Phys. Rep.,
184, 1 (1989).
3) Sawafta et al.: Proc. of Int. Conf. on Hypernuclear andStrange Particle Physics, Vancouver, July 4- 8, 1994, tobe published.
4) T. Harada: Nucl. Phys., A547, 165c (1992).
5) O. Morimatsu and K. Yazaki: ibid., A483, 493 (1988).
6) S. Okabe, T. Harada, and Y. Akaishi: ibid., A514, 613(1990).

RIKEN Accel. Prog. Rep. 28 (1995)

Nuclear Mesonic Exchange Currents
C.-L. Lin and S. Yamaji[One-photon exchange approximation, ~-isobar, Nuclear exchange currents.]
The well known electrodynamic theory and its
weaker interaction compared with that of strong interaction bring us one of the powerful methods, the electron scattering, to investigate electromagnetic properties as well as nuclear structures. At low energy theconstituents of nucleus are hadrons, and the mesonexchange takes responsibility of mutual interactions so
as to form the nucleus. On the other hand, the kindsof mesons and isobars increase with increasing transferred energy and momentum. Among those particles,
the dynamics of the ~-isobar in the nucleus is one of
the interesting problems in electronuclear physics. We
stand on the framework of quantum hadrodynamics,1)and investigate the roles of ~-isobar in the mesonicexchange currents and their related electromagnetic
properties. Both nuclear exchange currents and nuclear wave functions are derived from a Lagrangianwhich can bring the gauge invariance on our obtained
exchange currents.
First of all, we have to look for an appropriate Lagrangian. The two important symmetry principles, theLorentz invariance and the gauge invariance, show the
way of how to reach our goal. And the differential crosssection of the electron scattering which can be factorized into lepton and nuclear response tensors helps us
to be able to tackle t he target nucleus independentof the projectile. Furt her , in a position of quantum
hadrodynamics, one can interpret the hadronic theory
as an effective theory 2) of QCD so as to shelve therenormalization problem in the hadronic sector. 3) In
addition, we treat both ~-isobar and nucleon on equal
footing, that is, the ~-isobar is an independent particle inside the nucleus. Since the coupling between ~­isobar and pion is stronger than that of ~-isobar andp-meson, we consider only the pion, a and w mesons
this time. The model Lagrangian is as follows:

L =,p {

(i9' - er~ A~ - gt''Y~V"

Ff-Lv :::::: of-LAv - ovAv,
Af-L = electromagnetic field,
Gf-Lv :::::: 8f-LVv - 8vVv ,Vf-L = neutral vector meson w field,

rj.r,6. ~ 'Yf-L(Fi,N,~ + T3FrN,~),
F;'N 6. = electric form factor,
upp~r-script{ s = isoscalar, V = isovector}
lower-script { N = nucleon, ~ = ~-isobar}
Df-L1J =- 8·1J·of-L + ec t
· '3)
-L
A f,
Ba/3(~) :::::: ga/3 - ~'Ya'Y/3'

and 'l/J, 7ri, c/> and ~a represent nucleon, pion, a-mesonand ~-isobar field, respectively. The quantities Ti andfi express respectively the spinor and vector-spinor
isospins. Then we can easily get the nuclear electromagnetic currents in the one-photon exchange approximation. The parts generated by the ~-isobar are:J!;. = e {if.aaai9r~ll.i9- g;::"" [f.ao~({)(f xffja'" + h.c.]} ,where B~(~) = g~ - ~rarf-L, aa/3 = iba, r/3l!2, and~ is a parameter. The first term on the right handside gives the one-body current, and the second termis the ~-isobar exchange current. And the conservation of the whole electromagnetic currents is ensured
with a couple of assumptions that each coupling is up
to the first order, and the same isospin operators areused for all baryons. As to the nucleon wave functions ,we have to solve the coupled equations obtained fromthe Lagrangian for all cooperated hadrons. Since, at
this stage, the r-representation is better than the prepresentation,4) the electromagnetic currents should
also have the same representation. For this purpose,
we use the Rarita-Schwingers wave functions 5 ) for the~-isobar.

+ f;::"N 'Y~'Y5 (TiD~7rj)) - (mN - g':4»}'"+ ~ (i)"4>8~4> - m~4>2) - GG~"G"" - ~m~v"
2-2}+ 2'1 {(Dijf-L 7rj ) (Df-Lik7r k) - m7r7r

following:V")+ i3. a {aa/3 [(i~ - er~ Af-L - g~'Yf-LVf-L)- (m6. - g~c/»]} ~/3+ g;::,,6. {3.aBa/3(~) [fi(D~7rj)] 'l/J+h.c.}- 41 Ff-LvF f-LV .
The related physical quantities are defined as the

In order to study the role of ~-isobar in electronuclear physics, we are calculating nuclear response
functions using both nuclear wave functions and nuclear electromagnetic currents described above.

References
1) B. D. Serot and J . D. Walecka: Adv. Nucl. Phys.,
Plenum New York-London, 16, 1 (1986).
2) M. Benmerrouche et al.: Phys. Rev., C39, 2339 (1989).
3) K. Wehrberger: Phys. Rep., 225, 273 (1993).
4) G . B. West: ibid., 18C, 263 (1975).
5) W. Rarita and J. Schwinger: Phys. Rev., 60, 61 (1941).

29

RIKEN Accel. Prog. Rep. 28 (1995)

QeD Phase Transition in the Dual Ginzburg-Landau Theory
H. Suganuma, H. Ichie, * and H. Toki
[QCD phase transition, color confinement, dual Ginzburg-Landau theory.]
Color confinement is one of the most striking features of the nonperturbative QCD, and has been studied with much interest in the hadron physics. As forthe confinement mechanism, 't Hooft proposed an interesting conjecture of monopole condensation under
the abelian gauge fixing.1) In this scheme, color confinement is realized by condensation of monopole-likeobjects, which naturally appear in QCD by the abeliangauge fixing.1) This conjecture was strongly supported
by recent studies based on the lattice gauge theory.2,3)
The dual Ginzburg-Landau (DGL) theory4-6) is formulated as the infrared effective theory of QCD in termsof the QCD-monopole condensation. We have studied
relevant nonperturbative features as color confinement,
quark pair creation and dynamical chiral-symmetry
breaking using the DGL theory.4,5)
We investigate here the QCD phase transition at finite temperature in the DGL theory,6) where the QCDmonopole condensate is an order parameter of color
confinement. Although we include the dynamical effect of quarks in our framework, we concentrate in thepure gauge case because our main interest is color confinement property. In this case, the DGL theory issimply reduced to the ordinary Ginzburg-Landau theory in the superconductivity, so that we can easily derive its partition functional at finite temperature. 6) By
investigating the effective potential at finite temperature (thermodynamical potential), we find the reduction of the QCD-monopole condensate at high temperature. We also consider a possible reduction of
the self-interaction -\ between QCD-monopoles at hightemperature according to the asymptotic freedom of
QCD, and use a simple ansatz, -\( T) = -\(T-aTc)/Tc,
where a is chosen to reproduce Tc = 0.2 GeV. As thesemi-empirical quantity, we also calculate the string
tension k(T) at finite temperature. 4,6) We show in Fig.
1 the string tension k(T). We find the reduction of thestring tension at high temperature, which means thedecrease of the confining force there. Quantitatively,
our results with the variable -\(T) almost reproduce
the lattice QCD data shown by the black dots. 7 )In the DGL theory, there appear two important glueballs responsible for color confinement. One is thescalar QCD-monopole field, and the other is the axialvector dual-gauge field. 4) They correspond to the Higgs
field and the weak boson fields in the electro-weak standard theory, respectively. We show in Fig. 2 the massesof the two glueballs in the DGL theory.6) One finds thelarge glueball-mass reduction near the critical temperDepartment of Physics, Tokyo Metropolitan University

30

ature Tc. 6) It would be interesting to check our prediction by the lattice QCD and also by experiments.

k(T) [GeV/fm]

0.5

0.0

0.2

0.4
T[GeV]

0.6

Fig. 1. The string tension k(T) as functions of temperature
T for a constant>. and a variable >'(T). The lattice QeD
data in the pure gauge are shown by the black dots.

[GeV]

Fig. 2.

The masses of glueballs at finite temperature.

mB(T) and mx(T) denote the masses of the dual gauge

gauge field and the QeD-monopole field, respectively.
The dotted line denotes m = T. The phase transition
occurs at the temperature where mB,mX = T.

References
1) G. 't Hooft: Nucl. Phys., B190, 455 (1981).
2) A. S. Kronfeld, G. Shierholz, and U.-J. Wiese: ibid.,
B293, 461 (1987).
3) T. Suzuki and I. Yotsuyanagi: Phys. Rev., D42, 4257
(1990).
4) H. Suganuma, S. Sasaki, and H. Toki: RIKEN-AF-NP164 (1994); Nucl. Phys., B in press.
5) H. Toki, H. Suganuma, and S. Sasaki: Nucl. Phys.,
A577, 353c (1994).
6) H. Ichie, H. Suganuma, and H. Toki: RIKEN-AF-NP175 (1994).
7) M. Gao: Nucl. Phys., B9 (Proc. Suppl.), 368 (1988).

RIKEN Accel. Prog. Rep. 28 (1995)

Measurement of Fusion Cross Section
with Neutron Halo Nucleus IlBeA. Yoshida, T. Fukuda, Y. Watanabe, C. Signorini, 1. Mueller, F. Scarlassala, Y. Pu, Y. Mizoi, N. Aoi,
M. Hirai, J. Nakano, H. Kobinata, Y. Nagashima, T. Nomura, and M. Ishihara[sub-barrier fusion, neutron halo nucleus 11 Be.]
The main motivation of this research is concernedwith a possibility to observe the fusion cross sections ofneutron halo nuclei (such as 11 Be, 11 Li) considerablylarger or smaller than the one induced by the corresponding stable isotopes, due to the excitation of thesoft dipole mode, neutron breakup, etc. These effects,
in the case of the 11 Li halo nucleus, have been recently
discussed in various theoretical papers l - 3) with rather
different predictions. As the beam intensity of 11 Be
is larger than that of 11 Li by more than one order ofmagnitude, we first measured the excitation functionof the fusion cross section in the systems 11,10,9Be +209Bi with the same experimental setup. The fusion
process has been identified via the detection of the delayed a-particles emitted by the decay of the groundstate of the evaporation residues populated after neutron evaporation. This technique has an advantage ofclear identification of the fusion comparing with themeasurement of fission in the same systems.
The beams of Be isotopes were produced by thefragmentation process of 13C primary beam with 100
MeV /u energy and 100 pnA intensity on a Be production target with 12 mm thickness. They were thenseparated by the RIPS projectile fragment separator,
resulting in a purity of almost 100%. After the separation, an Al degrader plate was inserted in the beamline to reduce the secondary beam energy down toaround the Coulomb barrier. A typical beam intensityof 11Be was 140 kcps with the energy of 50 MeV±37%(in fwhm) and with the beam size of around 5 cm indiameter. With this simple deceleration method, thedistribution of the beam energy became wide, so thata TOF measurement was done event by event to determine the beam energy.
At the experimental target position, four 209Bi targets (500- 700 J..Lg/cm 2) evaporated onto a Mylar backing foil (70 J..Lg/cm 2), were surrounded by 9 Si surface
barrier detectors (SSD). Each detector had a size of
48 x 48 mm and a thickens of 300 J..Lm and they covered a solid angle of about 30% of 47r. The time gate
for the delayed a-decay coincidence was 2 J..Ls after thearrival of each beam particle. The neutron detector
walls surrounded the target chamber in order to measure neutrons originating from breakup fusion events
if any.
The a-decays from 216Fr (Ea = 9.01 MeV, T 1/ 2 =700 ns), which originate from 4n,3n evaporation with

11 ,lO Be beam respectively, and those from 215Fr (Ea =9.34 MeV, T1/2 = 120 ns), which originate from
5n,4n,3n evaporation with 11,10,9Be beam respectively,
were clearly observed with enough statistics to argue
the fusion excitation function around the barrier region.
Figure 1 shows the measured fusion excitation function in the system of 11 Be + 209Bi comparing withsimple theoretical calculation. Both data and theory
seem to agree well except for higher energy regions.
It is also found that the measured fusion cross sectionof lOBe shows almost the same magnitude as 11 Be, inpaticular, near the barrier region. From these results,
we can say that there is no strong indication of halo
neutron effect (e.g. enhancement/suppression) for a fusion reaction near the barrier region which has been
predicted by many theoretical calculations. Further
detailed analysis is now in progress by using the dataof neutron detectors in order to get information about
the breakup fusion reaction.

~100 +· l ··············/

:

40

so

216

•

4n

•

Sn 215 Fr

Fr

H
.

\

.c

5

t,.~

10

60

70

80

Fig. 1. The measured fusion excitation function. The x
error bars indicate an energy binning size in the analysis which corresponds to the TOF energy resolution ofaround 1.5 MeV, and y error bars indicate only statistical errors. The solid lines indicate a theoretical calculation by the PACE2 evaporation code using a simple
parameter set, in which the halo neutron effect of 11 Be
is not considered.

References
1) M. S. Hussein et al.: Phys. Rev., C46, 377 (1992).
2) N. Takigawa et al.: ibid., C47, 2470 (1993).
3) C. H. Dasso et al.: ibid., C50, R12 (1994) .

31

RIKEN Accel. Prog. Rep. 28 (1995)

Spectroscopy of 13Be Using 12Be Radioactive Beam
A. A. Korsheninnikov, E. Yu. Nikolskii, T . Kobayashi, D. V. Aleksandrov, M. Fujimaki, H. Kumagai,
A. A. Ogloblin, A. Ozawa, 1. Tanihata, Y. Watanabe, and K. Yoshida[NUCLEAR REACTIONS, radioactive nuclear beam, CD 2, Ce 2Be,p), E/ A = 55 MeV.]
We have performed spectroscopic studies of theheaviest known unstable beryllium isotope 13Be, which
was observed for the first time in Ref. 1 and recently
investigated in Refs. 2 and 3.
We have studied 4 ) under inverse kinematics the neutron transfer reaction de 2Be,p) at E = 55 A MeV
using the 12Be beam produced by the RIPS. Measurements were performed by the proton telescopes
at backward angles (Obab rv 115°-145°) with targets
CD 2 and C. The experimental setup is shown in Fig.
1. The proton spectrum from the CD 2 target is presented as a function of relative energy in the n+12Be
system, En-12Be, by a solid histogram in Fig. 2. The
dashed histogram shows the contribution from carbon.
This background corresponds to a low energy proton
spectrum from the target-like source (fragmentationof the target or evaporation from the target-like systern). The background does not allow to investigate ina reliable way the low-energy region in 13Be, where an
intruder s-shell state can be expected from the extrapolation 17 0 ~ 15C ~ 13Be (inversion of 5/2+- and1/2+ -states). Figure 2 shows the known 13Be state at

50

40

23

§30
o

U

20
10

0-4 -2 0 2 4 6 8 10 12 14 16 18

Fig. 2. Proton spectra from the reactions CD 2 C2 Be,p)(solid line) and CC 2 Be,p) (dashed line).

2 MeV above the n+ 12 Be threshold. In addition, threestates of 13Be at 5, 7 and 10 MeV above the n+12Be
threshold were assigned tentatively. The 5 Me V state
confirms the result of Ref. 2. The 7 MeV state differsfrom the tentative level, given in Ref. 2, at 8.5 MeV
above the threshold.
References
X-Strip " ......._....,.!.oo""
Y -Strip detector
Si-detectors

Fig. 1. Experimental setup.

321) D. V. Aleksandrov et al.: Sov. J. Nucl. Phys., 37, 474(1983).
2) A. N. Ostrowski et al.: Z. Phys., A343, 489 (1992).
3) S. Piskor et al.: Z. Phys., A, to be published.
4) A. A. Korsheninnikov et al.: Phys. Lett., B, in press.

RIKEN Accel. Prog. Rep. 28 (1995)

Excited States of 12Be in the Vicinity of He-Thresholds
A. A. Korsheninnikov, E. Yu. Nikolskii, T. Kobayashi, D. V. Aleksandrov, M. Fujimaki, H. Kumagai,
A. A. Ogloblin, A. Ozawa, 1. Tanihata, Y. Watanabe, and K. Yoshida
NUCLEAR REACTIONS, radioactive nuclear beam, pe 2Be,p), pe 2Be,p12,1l,10Be),[ pe 2Be,p8,6,4He), pe 2Be,pXHe XHe) , E/A = 55 MeV, p(8He,p), E/A = 33 MeV.
Previously excited levels in the neutron rich nucleus
12Be were investigated at excitation energies < 6 MeV.
On the other hand, the region of thresholds for decay tohelium isotopes attracts special attention (,.....,10 MeV).
In the vicinity of these thresholds, 12Be states can exist with an exotic cluster structure with He-like subsystems.
We have studied 1) the elastic and inelastic scattering 12Be+ p at E = 55 A MeV using the 12Be beam
produced by the RIPS. To provide a proton target , weused CH 2. Protons were measured by two telescopes ofsolid state detectors at laboratory angles B~ab ,. . ., 50°80°. We also investigated the coincidence between protons and particles from t he dissociation of 12Be (beryllium and helium isotopes as well as neutrons) , whichwere measured using a charge fragment detection system (dipole magnet , drift chamber, hodoscope of plastic scintillators) and neutron walls (plastic scintillators).
A measured inclusive spectrum of protons is shownin Fig. 1. A strong peak from the elastic scattering isseen as well as the known state at 2.1 MeV. We also
marked the other known states at 4.6 and 5.7 MeV,

1

where some structure exists in the spectrum. In addition, there are new states at 8.6 and 10 MeV. It isstressed by the insert in Fig. 1 (summing over channels), where these states are clearly seen (note also
the structure at ,. . ., 13- 14 MeV). The states are quite
narrow, r ::; 0.5 MeV. Figure 2 shows that the 8.6
MeV state lies slightly below the first helium threshold,while the 10 MeV state is located above this thresholdand close to the second helium threshold. Measuring
proton spectra in coincidence with beryllium and helium isotopes , we obtained data, which show that the
10 MeV state has low partial width for decay to berylliums, ftotal/re2Be* --+ XBe) = 3.6 ± 1.6. One morestate at ,.....,14 MeV was observed, which also decays into
heliums. Since the decay energy to berylliums is muchhigher than the decay energy to heliums (Fig. 2), adifference in the penetration factors should be large,
and thus the helium reduced width should be predominant in the states at 10 and ,.....,14 MeV. So these levels
likely have a cluster structure He+He. Since 6He and
8He consist of an a-core plus weakly bound neutrons,
these 12Be states can actually have an exotic structurea + a + 4n.

....14200

g.s.

12.058~10.1~

10±0.15&6±O.15

40

160

8.946

5.70
4.56
270
210

~1
3.168 1
2+
0+

16

20

Fig. 2. Levels of 12Be.
Fig. 1. Proton spectrum from pC 2Be,p). Curves show
possible backgrounds from the phase space p+llBe+n
and the n-n final state interaction in the channel
p+lOBe+n+n.

References
1) A. A. Korsheninnikov et al.: Phys. Lett., B, (1995).

33

RIKEN Accel. Prog. Rep. 28 (1995)

Systematic Behavior of Ejectile Spin Polarization in the
Projectile Fragmentation Reaction
H. Okuno, K. Asahi , M. Ishihara, H. Deno, H. Sato, J. Nakamura, T. Nakamura, F. Ambe, T. Ichihara,
N. Inabe, M. Iwamoto, Y. Ohkubo, T. Kubo, Y. Kobayashi , A. Yoshida, M. Adachi, T. Shimoda,
N. Takahashi, H. Miyatake, D. Beaume,*1 D. Morrissey,*2 and W.-D. Schmidt-Ott*3
NUCLEAR REACTIONS Xe 5 N, 12Be3B))Y, E/A = 70, 112 MeV/u; deduced[ spin polarization of 12B e 3B) nuclei from {3-ray asymmetry.
Ejectile spin polarization P in intermediate-energy
projectile fragmentation has been measured for different targets and incident energies using RIPS fragIn this report , we present thement separator.
recent progress of the study on the polarization
mechanisms. 1)

-

~ 1.0

1

Some representative results are shown in Fig. 1.
The behavior of the polarization spectrum is mostly
compatible with the prediction of the kinematicalmodel of Ref. 2. In more quantitative discussions, however, we note that some aspects deviate from the model
predication. In particular the model infers that the

(a)

'-'

-

't1 0.5
CD>= 0.0
~

'-'

~

I
I
I
I

20
10

0

:g

-~

0

N

·5 -10

-

I
I

0

~

-20
-10 -5 0

5-10 -5 0

5-10 -5 0

5-10 -5 0

5-10 -5 0

5(p-PO)/PO .(%)
Fig. 1. Yield (upper part) and spin polarization (lower part) spectra as functions of fragment
momentum p. for (a) 14N (39.4 MeV lu) + 197 Au ~ 12B (BL = 5.0°) + X, (b) 15N (68.0
MeV lu) + 197 Au ~ 13B ((1£ = 4.0°) + X, (c) 15N (109.6 MeV lu) + 197 Au ~ 13B ((1£ = 2.0°)+ X, (d) 15N (67.3 MeV lu) + 93Nb ~ 13B ((1£ = 2.5°) + X, (e) 15N (68.0 MeV lu) + 27 Al~ 12B ((h = 10) + x.

yield weighted average of the polarization (P) shouldbe zero and the zero-crossing of P should occur at the
momentum corresponding to the velocity of the projectile, Po. These features are missing in many of theobserved spectra, indicating a need for a modified theory.
A closer inspection of the angular momentum transfer mechanism clarified that the general feature that(P) tends to be negative can be accounted for if theremoval of the nulceons occurs in a position awayfrom the line connecting the center of the two nuclei.
Solid curves in Fig. 1 show results calculated including
such effects, reproducing gross behavior of the spectra

*1
*2
*3

34

Institut de Physique Nucleaire, France
NSCL, Michigan State University, USA
II. Physikalisches Institut , Universitat Gottingen

rather well.
The appearance of large polarization around Po isparticularly useful when the reaction is applied to produce spin polarized nuclear beams since one can employ a thick target and relatively wide momentum window to gain in the beam intensity. In fact , the phenomenon is exploited for the efficient measurements ofnuclear moments of neutron-rich nuclei. 3)
References
1) H. Okuno et al.: Phys. Lett. , B335, 29 (1994).
2) K. Asahi et al.: ibid., B251 , 488 (1990).
3) H. Veno et al.: This report , p. 41 and p. 42.

RIKEN Accel. Prog. Rep. 28 (1995)

Interaction Cross Sections and Radii of IIC and 12N
A. Ozawa, T. Kobayashi, D. Hirata, 1. Tanihata, O. Yamakawa,*1 K. Ornata, K. Sugimoto,*2 N. Takahashi,
T. Shimoda, D. 0Ison,*3 W. Christie,*3 and H. Wieman*3
NUCLEAR REACTIONS Be,C,AI(llC,llC)X, Be,C,AI(12N, 12 N)X, E/A = 730 MeV; measured interaction[ cross sections a I, deduced root mean square radii and effective deformation parameters.
The recent development of radioactive beams provides the new measurement of the radii of unstable
light nuclei. On the other hand, a recent developmentof the detection technique of quadrupole moments provides the new measurement of quadrupole moments(Q) of light mirror nuclei. Some of the isospin dependence of matter radii were measured for A = 6-12,
17. 1,2) In the present experiment, we have measured
the interaction cross sections and radii of llC and 12N
on target nuclei Be, C, and Al around 730A MeV. Fromthe present experiment, we can obtain a complete set ofradii and Q of mirror nuclei in the mass number A = 8,
11, 12, and 17. Thus, it becomes possible to compare
the systematics between the radii and quadrupole moments for thease mirror nuclei. The systematics suggest the solution of the proton-halo problem of 8B,
where the relatively large quadrupole moment , thatsuggests the proton-halo in the shell-model analysis,3)
conflicts no enhancement of the matter radius. 1)
The secondary beams of llC and 12N were produced
through projectile fragrrientation of 18 0 and 20Ne primary beams (800A MeV), respectively, that were accelerated by the Bevalac at the Lawrence Berkeley Laboratory. The secondary isotopes were produced in a
production target of Be and were separated by theirrigidity using the beam-line as described in a previous
paper.4) The interaction cross section was measured
by a transmission method and the effective root-meansquare (RMS) radii are derived by the same manner asa previous paper. 4) The effective RMS matter radii aredetermined as, 2.12 ± 0.06 fm for llC and 2.47 ± 0.07
fm for 12N.
Effective deformation parameters (f3eff) are derived
from the equation, Q = Qo[1(21 -1)]/[(1 + 1)(21 + 3)]
and Qo = 0.7569ZRo 2 f3eff(1 + 0.1577f3eff), where 1 is
the intrinsic spin and Ro is the radius obtained from
effective RMS charge radius. Isoscalar and isovector
IS
parts for f3eff are derived by f3eff= f3eff + + f3eff -,and f3eff IV = f3eff + - f3eff -, where + and - mean the

*1

*2

*3

1

IV

signs of T z . Obtained f3eff IS and f3eff
are shown in
Fig. 1. f3eff IV is almost zero in the present mass range,
but f3eff IS shows the strong mass number dependence.
f3eff IV rv 0 suggests that deformation is almost equal
within a mirror pair. The relatively large deformation
has .been observed for A = 8. This suggests that therelatively large quadrupole moment of 8B is due notto the proton-halo but to the relatively large deformation of the nucleus. In the shell model description,
deformation can be described by effective charges for
proton and neutron. Present results also suggest thatthe strong mass dependence of effective charges is necessary among such light nuclei.

1.2
1.0
0.8
0.6

0

-0.2
-0.4

o

~

~0.4
CCl.. 0.2
o.~

PerrS
• PerrV

Q

i i

•

•

0

6

8

10

12

14

16

18

A
Fig. 1. The mass dependence of the effective deformation
parameters. The Isoscalar part is shown by the open
circle. The Isovector part is shown by the closed circle.
The parts in the mass 11 and 12 are obtained from thepresent experiment.

References
1) I. Tanihata et al.: Phys. Lett., B206, 592 (1988).
2) A. Ozawa et al.: ibid., B334, 18 (1994).
3) T. Minamisono et al.: Phys. Rev. Lett., 69, 2058 (1992).
4) I. Tanihata et al.: ibid., 55, 2676 (1985).

Fukui Prefectual University
Osaka University
LBL, Berkeley, U.S.A.

35

RIKEN Accel. Prog. Rep. 28 (1995)

Radii of Na Isotopes and the First Direct Evidence of
Neutron Skin
T. Suzuki, K.-H. Behr,*! O. Bochkarev,*2 A. Briinle,*! K. Burkard,*! L. Chulkov,*2 P. Egelhof,*! H. Geissel,*!
M. Golovkov,*2 D. Hirata, H. Irnich,*! Z. Janas,*! H. Keller,*! T. Kobayashi, G. Kraus,*!
G. Miinzenberg,*! F. Nickel,*! S. Neumaier,*3 A. Ozawa, A. Piechazek,*! E. Roeckl,*!
W. Schwab,*! K. Siimmerer,*! K. Yoshida, and 1. Tanihata[Nuclear Structure, Neutron skins, Radioactive beams.]
From a series of experiment, it is suggested thatthick neutron skins are formed in unstable neutron richnuclei. Because no stable nucleus shows any of the decoupling phenomena, it is essential to find and study
the decoupling for understanding the nuclear interactions as well as the nuclear matter of an asymmetricmixture of proton and neutron. Also a nucleus withneutron skin or halo is expected to show a variety of
new collective excitations that are not expected in thestable nuclei.
Evidence of a neutron skin of thickness about 1 fm
was presented by Tanihata et al. in 6He and 8He nuclei
from the measurements of interaction cross sections
and the two/four neutron removal cross sections.!) Although it is not unreasonable, yet they had to assume
that the correlation between valence neutrons in these
nuclei is small or not very much different from that
expected from a simple shell model.
We have measured the interaction cross sections of
N a isotopes from A = 20 to 32. Sodium isotopes
provide a unique opportunity, because the root-meansquare charge radii of N a isotopes were determined by
the isotope shift measurement, and thus direct comparison of the charge and the neutron radii can be
made.
The measurements are made at the FRS facility of
the GSI in Germany. Beams of 20- 23 Na and 25- 32 Na at
900A MeV were produced from Ar beam accelerated
by the heavy-ion synchrotron SIS. The first half of the
FRS is used to separate and identify the incident N abeams. The reaction targets ofC with 7 and 4 g/cm 2 inthickness were used. Then the last half of the FRS wasused to identify and to count the non-reacted nuclei inthe target. This method provided the transmission
measurement of the interaction cross sections.
The solid circles in Fig. 1 show the preliminary

*1
*2
*3

36

GSI, Darmstadt, Germany
Kurchatov Institute, Russia
TH Darmstadt, Germany

results of the determined interaction cross sections.
The solid line in the figure shows the expected crosssections assuming the matter density distribution to
be the same as the proton distribution except for thenormalization scaled by A/Z. The proton distributions are calculated by a relativistic mean field (RMF)
model that reproduces the isotope shifts very well. 2)
The dotted line shows the cross section calculated withthe matter density distribution obtained by the same
RMF model. This model gives gradual growth of theneutron skin for neutron rich Na isotopes. It is seenthat the observed interaction cross sections are muchlarger than the ones predicted from the proton density
distribution and close to the RMF matter density distribution that has large neutron skins. The thicknessof the neutron skin (Rn rms - RP rms ) reaches 0.6 fm for
3 2 Na.

:0 1500 r--r-----.--~r_~',---.--.-----.--r-...--,~-r-...-,g#N~ + Creaction at 900A MeV l~ :: II /f+i'i'1r~:~~

B 1000 '----'-___'_~..J...........---'-__'_...J..__'__'____'_-'--~'---'-__'
~
25
30
A
20
Fig. 1. Interaction cross section of Na isotopes.

References
1) I. Tanihata et al.: Phys. Lett., B289, 261 {1992}.
2} D. Hirata et al.: Phys. Rev., C44, 1467 (1991).

RIKEN Accel. Prog. Rep. 28 (1995)

Coulomb Excitation of 32Mg
T. Motobayashi, Y. Ikeda, Y. Ando, K. Ieki, M. Inoue, N. Iwasa, T. Kikuchi, M. Kurokawa, S. Moriya,
S. Ogawa, H. Murakami, S. Shimoura, Y. Yanagisawa, T. Nakamura, Y. Watanabe, M. Ishihara,
T. Teranishi, H. Okuno, and R. F. Casten*[208Pbe 2Mg, 32 Mg ,),)208Pb; Coulomb excitation, deduced B(E2).]
The Coulomb excitation of a very neutron-rich nucleus 32Mg to its 2+ state was studied using a radioactive beam of 32Mg at 49.2 MeV/nucleon on a 208Pb
target. 1) The RIPS facility of the RIKEN Ring Cyclotron provided a 32Mg beam. A 208Pb target of
350 mg/cm 2 thickness was placed at the focal pointof the RIPS system.
Scattered 32Mg nuclei were detected by a counter
telescope placed 35 cm from the target in the air after
passing through a 25 J.Lm thick mylar window. The
telescope consisted of five ion-implanted silicon detectors of 40x40 mm 2 effective area and 400 J.Lm thickness.
The particle was identified by the ~E- E method, andwas good enough for the present purpose of selecting
32Mg among other Mg-isotopes. The excitation to the2+ state was identified by measuring the')' ray deexcitation of the 2+ state in coincidence with the scattered
32Mg ions.
Sixty NaI(TI) scintillators surrounded the target todetect the ')'-rays. Each scintillator crystal is of rectangular shape with size 6 x 6 x 12 cm3. The high granularity of the setup allows one to measure the angle ofthe')' ray emission, which is useful in correcting large
Doppler shifts of the')' rays from the excited 32Mg thatwas moving with v / c ~ 0.3.
Figure 1 shows the ')'-ray energy spectrum associated with the 32Mg + 208Pb inelastic scattering. It is
obtained by a sum of spectra for all the NaI(TI) scintillators after the Doppler shift correction. Accidental
coincid,ence yield is subtracted in the energy spectrum
shown in Fig. 1 by using the data obtained by setting a

150

~ 100

206Pbe2Mg,32Mg -y)206 Pb

~

o

(")

E;n=49 ,2 MeV / u.........
rn
+>
C 50

gate at the region beside the true-coincidence peak inthe 32Mg_, time-difference spectrum. As clearly seenin the figure, only one photo-peak at 0.89 MeV corresponding to the 2+ ~ 0+ transition was observed.
An experimental deformation parameter f3 = 0.512±
0.044 was extracted by comparing the predicted effective cross section with the experimental value obtained
from the photo-peak yield. The theoretical effective
cross section was obtained by a coupled channel calculation with a Monte Carlo simulation taking into accout the finite solid angle of the particle detector, ')' raydetection efficiency, multiple scattering in the target,
and finite energy and angular spread of the incident
beam. The error contains a possible uncertainty regarding the choice of the optical potential and that in
the estimation of nuclear excitation amplitude, besides
experimental uncertainties. This deformation parameter corresponds to B(E2) = 454 ± 78 e 2fm 4 .
The present result agrees with 450 e2fm 4 predicted
in a shell model of Fukunishi, Otsuka and Sebe. 2) The
prediction exhibits this large B(E2) value for 32Mg if
the model space is extended to the p-f shell, and it
reproduces the present data. On the other hand, nosuch large value is predicted with a limited model space
where the valence nucleons are only in the s-d shell orbitals. This suggests a large mixture of the p-f shell orbitals for 32Mg and vanishing of the N = 20 shell gap,
which result in large deformation. The same conclusion is obtained by comparing the present result with
the B(E2) values calculated by the NpNp scheme. 3) A
good agreement is obtained for 32Mg (369 e2fm 4 ) if theneutron number of 20 is not treated as a magic number, in contrast to the prediction with an N = 20 shellclosure (68 e2fm4) that much underestimates the data.
The present result demonstrates the usefulness of
Coulomb excitation at several tens MeV/nucleon,
where large cross sections and availability of thick targets enable experiments with unstable ' nuclear beams
of low intensity.

;::j

o
()

Fig. 1. Energy spectrum of , rays emitted from the32Mg+208Pb inelastic scattering at 49.2 MeV lu incident energy. The Doppler shift is corrected for.

References
1) T. Motobayashi et al.: Rikkyo Univ. Preprint, RUP-9413; Phys. Lett., in press.
2) N. Fukunishi, T. Otsuka, and T. Sebe: Phys. Lett.,
B296, 279 (1992).
3) R. F. Casten and N. V. Zamfir: Phys. Rev. Lett., 70,
402 (1993).

Physics Department, Brookhaven National Laboratory,
U.S.A.

37

RIKEN Accel. Prog. Rep. 28 (1995)

Beta-decay of Neutron Rich Nucleus 14Be
N. Aoi, M. D. Belbot, M. Hirai, E. Ideguchi, M. Ishihara, T. Kishida, J. J. Kolata, G. Liu, H. Miyatake,
T. Nakamura, H. Okuno, H. Sakurai, S. Shimoura, T. Shirakura, T. Teranishi, Y. Watanabe,
S. Yamamoto, A. Yoshida, and M. Zahar[RADIOACTIVITY 14Be(,B-), measured ,B-delayed neutron deduced logft. 14B deduced level.]
A nucleus very far from the stability line often has alarge Q/3 and decays into excited states of the daughter
nucleus over a wide energy range, affording a rich domain of nuclear spectroscopy. In the case of extremely
neutron rich nuclei, most of the final states are unstable with respect to neutron emission. Hence, neutron measurement provides a useful means to study
the properties of ,B-decay.
We measured the energy spectrum of ,B-delayed neutron and ,-ray of very neutron rich nucleus 14Be. 1)
A 14Be beam was provided by the RIPS (Riken
Projectile-fragment Separator) at the RIKEN Ring
Cyclotron using projectile fragmentation of 100A MeV
18 0. The 14Be nuclei were implanted to five thin (300
Mm) Si- detectors located at the final focal point with atypical intensity of 3 x 10 2 counts/sec. Emitted ,B-rays
were detected by plastic scintillation counters placedon both sides of the Si-detectors. Energies of the delayed neutrons were measured by means of a time-offlight method. The neutron flight path was set about 2
m so that the energy resolution of neutron was 1 MeV
at 15 MeV. The energy threshold of the neutron detector was set at 200 keY. Delayed ,-ray energies were
measured by two Ge detectors located at about 13 cm
from Si-detectors.
In the measured neutron TOF spectrum shown in
Fig. 1, we observed a strong peak at the energy of
282.7 ± 1.7 keY.

The branching ratio corresponding to this strong
peak is determined tentatively to be 63 ± 15%. The
detection efficiency for neutrons was obtained from theseparated run using 17N beam whose neutron energies
and neutron emission rate are well studied. 2 )The strong peak in the neutron spectrum may berelated to two alternative possibilities of the decay
scheme. The one candidate is the decay to a level
just above the neutron threshold which is followed byneutron emission leading to the ground state of 13B
without accompanying any g-emission (Fig. 2 case 1).
The logft value correspond to this decay is 3.7 ± 0.1
which indicate that this decay is due to a allowed transition.
0+
148e

0+
~6.1Mev

6.1 MeVlog ft = 3.7"Be \log ft = 3.2
~-

\

W
-5.01
= 3.68n\

3/2-=== - - -13f3

2--

1"8

I

Case 1 10.00(0.97)\n-----1

-501
368

===

-

y

i1"8

13

3/20008

I Case 21

Fig. 2. Two candidates of the decay scheme of 14Be related
to the 283 ke V neutron. See text for further details.
~500

rn
I=:

280ns
283keV

Prompt ",(- ray

~

....,

'-...400

I=:::l

Threshold200keV0300~'"d 200

Q)

~

100

100

200

300

The other possibility is the decay to a higher excitedstate of 14B, which decays to an excited state of 13B
by emitting a neutron. In this case, ,-emission shouldtake place successively (Fig. 2 case). 2) If we assume thisscheme, the decay is ascribed to an allowed transitionof logft = 3.2 ± 0.1.
The analysis for the ,-ray energy-spectrum is now inprogress, in expectation of information to distinguishbetween the alternative possibilities.

400

Neutron Tof Spectrum [ns]References
Fig. 1. TOF spectrum of neutron from 14Be. The sharp
peak of approximately 7 ns is due t the prompt ')'-ray.
The peak at 280 ns corresponds to the neutron withenergy of 283 ke V.

381) T. Kishida et al.: RIKEN Accel. Prog. Rep., 27, 46(1993).
2) H. Ohm et al.: Nucl. Phys., A274, 45 (1976).

RIKEN Accel. Prog. Rep. 28 (1995)

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 19CCB+ n); measured ,a-delayed En and deduced Ex in 19N.]
The ,a-delayed neutron decay of 19C has been studied
mainly from the astrophysical interest using the timeof-flight (TOF) technique. In the previous report,l)the motivation and the experimental setup for thepresent experiment were described in detail.
A typical ,a-delayed neutron spectrum is shown in
Fig. 1. Several peaks have been identified as ,a-delayed
neutrons from 17B and 16C, which are, respectively, a
contaminant in the 19C beam and its daughter nucleus,by the independent experiment to study the ,a-delayed
neutron decay of 17B. One ,a-delayed neutron peakfrom 19N, which is the daughter nucleus of 19C, has also
been identified, since the neutron energy matches theenergy difference between one of known excited statesin 19 0 and the 18 0 + n threshold, and the peak shows
the different time dependence from other peaks. Finally, three lines with energies of En (lab) = 1.49, 1.01,
and 0.45 MeV belong to the ,a-delayed neutron decayof 19C. Half-lives obtained by the time spectra gatedby the three lines (Tl/2 = 46 ± 4 ms) show the goodconsistency with the previous measurement (Tl/2 =49 ± 4 ms).2) All three lines in TOF are coincident
with the "'I-ray from the level with Ex = 115 keY in
18N. And the line with En = 0.45 MeV is coincident
with the 'Y-ray from the level with Ex = 587 keV in
18N. Using the information, we assign newly obtainedlevels in 19N, as shown in Fig. 2. The closest level tothe neutron emission threshold in 19N lies above 1
MeV from the threshold. Thus, in the temperature
range of interest,3) these newly obtained levels do notaffect the big bang nucleosynthesis in imhomogeneousmodels.
t'V~97(11)MeV

19C

\

~-

Ex (MeV)

1.2 I""T""-------------.

7.01
6.50
6.38

.- 1.0-~o~(0.587)~~~..........._ ..... (0.1l5)
5.32 18(0)N+n.c., 0.8
'i)

c::

§ 0.6

.c

~

§ 0.4
ou

0.2

Fig. 2. Decay scheme of 19C.

O~~-~~-~-~-L-~

o

80

160

240

TOF (nsee)
Fig. 1. Time of flight neutron spectrum following the,a-decay of 19C. The neutron energies (in MeV) are givenin the laboratory system.

References
1) A. Ozawa et al.: RIKEN Aeeel. Prog. Rep., 27, 45(1993).
2) J. P. Dufour et al.: Phys. Lett., B206, 195 (1988).
3) F. K. Thielmann et al.: Nuclei in the Cosmos, SpringerVerlag, Berlin, p. 147 (1992).

39

RIKEN Accel. Prog. Rep. 28 (1995)

Magnetic Moment of Proton Drip-Line Nucleus 9C
K. Matsuta, M. Fukuda, M. Tanigaki, T. Minamisono, Y. Nojiri, M. Mihara, T. Onishi, T. Yamaguchi,
A. Harada, M. Sasaki, T. Miyake, S. Fukuda, K. Yoshida, A. Ozawa, T. Kobayashi,
1. Tanihata, J. R. Alonso,* G. F. Krebs,* and T. J. M. Symons*
NUCLEAR REACTION 12C + 12C, E = 67A MeV; measured (3-ray asymmetry of[ 9C, nuclear magnetic resonance; deduced magnetic moment of 9C ground state.
The technique of polarized radioactive nuclear
beams has been applied to the (3-NMR study of the
proton drip-line nucleus 9C(11T = 3/2-, Tl/2 = 126
ms). The magnetic moment of 9C was measured for the
first time. With the known magnetic moment of 9Li,
the present result gives us a pair of nuclear magnetic
moments in the A = 9 isospin quartet (11T = 3/2- ,T = 3/2) , which is the first example of such pair magnetic moments for T = 3/2.
Polarized 9C nuclei were produced through the 67 A
MeV 12C + 12C collision at RIKEN's K540 cyclotron
and separated by the RIPS (RIKEN Projectile Fragment Separator). The purified 9C nuclei were slowed
down by an energy degrader and were implanted in acooled Pt foil (30K) placed in a strong magnetic field
Ho = 4.000 kOe to maintain the polarization obtained
through the reaction. The NMR of 9C was observedby means of the asymmetric beta-ray emission.
The NMR spectrum obtained by the polarization
destruction method is shown in Fig. 1. By fitting a
Lorenzian to the NMR spectrum, the resonance frequency was obtained as VL = 2827.3 ± 0.4 kHz. From
the result , a preliminary value for the magnetic moment of 9C was obtained as iJ.L i = 1.3914 ± 0.0005 J.LN.
The sign of J.L(9C) can be reasonably assumed to be
negative for the further discussion. The obtained magnetic moment is very much quenched from the Schmidt
value -1.91 J.LN. Using the iso-scalar moment analysis
summarized by the relation; J.L(Tz = -3/2) + J.L(Tz =+ 3/2) = J + 0.380(a), with the known magnetic

LBL, Berkeley, U. S. A.

40

1

moment J.L(9Li) = 3.4391 ± 0.0006 J.LN,l) the spin expectation value is obtained as (a) = 1.44. This value
is unusually large compared with other even-odd nuclei and is very much deviated from the theoreticalvalue (a) = 1.0 calculated using the Cohen-Kurathwave function with the free nucleon g-factors. 2) This
discrepancy may be attributed to unknown anomalous
structures of the proton drip-line nucleus.

-

9C in Pt (T =30K)~= 4.000 kOe

2.0

~
~

-0 1.02Wor

0.0 r---~--------------~r-~~

~

Z

-1.0
2822

2826

2830

~ 3000Frequency (kHz)Fig. 1. NMR spectrum of 9 C in Pt .

References
1) F. D. Correll et al.: Phys. Rev., C28, 862 (1983).
2) H . Sagawa: private communication.

RIKEN Accel. Prog. Rep. 28 (1995)

Magnetic Moment of Very Neutron-rich Nucleus 17B
H. Ueno, H. Izumi, K. Asahi, H. Okuno, K. Nagata, H. Ogawa, M. Adachi, H. Sato, Y. Hori, A. Yoshida,
N. Aoi, G. Liu, M. Ishihara, W.-D. Schmidt-Ott, T. Shimoda, H. Miyatake, S. Mitsuoka, and N. Takahashi
NUCLEAR REACTION 93Nb + 22Ne, E/A = 110 MeV/nucleon; measured (3-ray asymmetry[ of 17B, nuclear magnetic resonance; deduced magnetic moment of the ground state for 17B.
In order to investigate the effect of a large neutron excess on the nuclear tructure, we carried out
the measurement of a magnetic moment for the very
neutron-rich nucleus 17B which is supposed to be aneutron-halo nucleus. 1) The magnetic moment of 17B
was determined by using a spin polarized radioactive
beam from the projectile fragmentation reaction. 2) 17B(J7r = ~-, t! = 5.08 ms, Q/3 = 24 MeV) was produced with a beam of 22Ne on a 1.07 g/cm 2 thick 93Nb
target at E / A = 110 MeV /u. Fragments emitted at(lL = 1.5±1.0° were analyzed in the projectile fragment
separator RIPS, and were implanted in a Pt stopper,
to which a static magnetic field of 1000 Gauss wasapplied. For the determination of the magnetic moment, we employed the adiabatic fast passage (3-NMR
method: The up/down ratio of (3-ray yields from theimplanted 17N was measured for several different frequency bins, over which the frequency of an oscillating
field Bl was swept.
In the first measurement, we performed a number ofruns by changing the positions and width of the bins
run by run, each resulting in a low-statistics spectrum.
In such a situation the conventional method of analysis
did not allow us to gather the data into a spectrum ofsignificant statistics for deduction of a conclusive result for the magnetic moment. In order to overcome
this difficulty we developed a new method of analysis
in which all data are analyzed in terms of a probability distribution by respecting the characteristic featureof the adiabatic fast passage method. The probability
distribution function derived by this method is shown

1

in Fig. 1. This result was confirmed in the second measurement in which we concentrated on the frequency
region suggested by the above result, as shown in Fig.
2. From these results we could determine the absolutevalue of I-" within ±3.5% accuracy. We then carried out
a precision measurement by dividing this region into
seven pieces. The result is shown in Fig. 3. The result
preliminarily derived from Fig. 3 is11-"1 = 2.540 ± 0.015 (n.m.).

o. . ;1 .

l=:

!faff

1.01

Ho =953.13 Gauss.~ 0.99~ 0 .98

~0.97
~

f

0 .96

0 .95
1160

1200

1240

1280

1320

frequency (kHz)Fig. 2. The result of the second measurement.

0 .77 !'=---<~--=--'=":""-----------"'l.g~ 0.75

e0

0 .73

0 .71

~=252 ~g(l~IGross

1220

1260

1300

1340

frequency (kHz)Prob. - 96Ck

Fig. 3. NMR spectrum obtained from the last measurement.

~ 3

2.4

2 .5

2 .6

2 .7

2.8

Magnetic Moment (n.m.)

References
1) E. Litard et al.: Europhys. Lett., 13, 401 (1990).
2) H. Okuno et al.: Hyperfine Interact., 78, 97 (1993).

Fig. 1. Probability distribution function deduced by applying the newly developed method of analysis. See
text.

41

RIKEN Accel. Prog. Rep. 28 (1995)

Magnetic Moment of 17N
H. Ueno, H. Izumi, K. Asahi, H. Okuno, K. Nagata, Y. Hori, H. Sato, A. Yoshida,
G. Liu, N. Aoi, H. Ogawa, M. Adachi, and M. Ishihara
NUCLEAR REACTION 93Nb+ 18 0, E/A = 70 MeV/nucleon; measured {3-ray asymmetry of[ I7N, nuclear magnetic resonance; deduced magnetic moment of the ground state for I7N.
Nuclear magnetic moment of 17N was determined byusing a spin polarized radioactive beam from the projectile fragmentation reaction. l ) I7N (J7r = ~ -, t~ =4.173s, Q/3 = 8.680 MeV) was produced with a beamof 18 0 at 70 MeV /u onto a 93Nb target of 428 mg/cm 2
thickness. Fragments emitted at ()L = 2.5 ± 1.0°, after
being isotope-separated by RIPS, were implanted ina carbon graphite stopper to which a static magnetic
field of 2475 Gauss was applied. Nuclear magnetic resonance was observed through a change in the up/down
asymmetry of {3-rays emitted in the decay of 17N. The
NMR spectrum obtained is shown in Fig. 1. The experimental magnetic moment J.L was deduced from thedip position in the spectrum as
IJ.LI = 0.352 ± 0.002 (n.m.).

No correction was made for the Knight shift and chemical shift since their effects are considered to be smaller
than the experimental error assigned to J.L (the Knight10- 4 from the Korringa conshift is estimated as K
4stant TI . T = 2.7 X 10 sec·K, and the chemical shiftnormally takes the order of 10- 4 10- 5 ).

plotted. We note here the large outward deviationfrom the Schmidt value, representing the expected absence of the Ml core polarization for the p 12 orbit. 6 )Thus the magnetic moments, in particular their deviation from the Schmidt values, of I7N and otherodd-mass N isotopes may afford a sensitive test of
p-sd cross shell interactions. In fact in the case of
17N the WBP model shows that the magnetic moment is largely determined by the admixture of the17r(p2)3(Pl)2>J=~ ®lv(d 2 )2 >J=2 configuration, for22
whiCh the expectation value for J.L amounts to 8 times
that of the major components having proton configurations of 17r (p 1)> J = ~ type. The contribution of such2
a configuration, involving the excitation of the sd-shellneutrons by the p-shell protons through the cross-shellinteractions, may play an increasingly important rolein the ground state of heavier N isotopes, and well deserves of further experimental investigation.
~ .

;rac Valu~ = +0.667

f"'V

f"'V

·0.25

.-

E · 0.3

5:::L ·0.35

17N

Schmidt Value = .0264~......

.-

. ..

,~

o

g.s.

1.96

1

·0.4

1,,,=4.173s. J~=1/2-

CKPOT .--

1.95

=
~

·0.45 L-.}1~3-L--:1~5---=-..l-----L17~~=1~9~.g 1.94

Mass Number

Q.
:::I 1.~3
1.92

rf off

1 .91 1...J....I.....J...J.....L-L...L..J.....l.-I....L...I....L...I.....I---L.<....I....L....i...J......l.-I...L...-L....J

1240

1260

1280

1300

1320

1340

1360

frequency (kHz)Fig. 1. NMR spectrum obtained for 17N. The up/down
ratio of f3-rays is plotted as a function of the frequencyof an oscillating field.

In Fig. 2 the experimental value is compared withshell model calculations 2- 4) based on the OXBASH
program. 5 ) Here a negative sign is assumed for the
I7N experimental value. The calculation with the p-sd
cross shell interactions recently proposed by Warburton and Brown (referred to as WBP in Fig. 2)2) reproduces the experimental value better than the one
based on the Millener-Kurath interaction (MK).3) In
order to clarify effects of the neutron excitation to
the sd-shell, the calculation with Cohen-Kurath interaction (CKPOT)4) in the p-model space is also
42

Fig. 2. Comparison of the experimental magnetic moments for N isotopes of odd mass with shell model calculations. MK: the Millener-Kurath p-sd cross shell effective interaction. WBP: the p-sd cross shell effective interaction recently proposed by Warburton and Brown.
CKPOT: the calculation within a p-model space using
the Cohen-Kurath p-shell effective interaction. See text.

References
1) K. Asahi et al.: Phys. Lett., B251, 488 (1990).
2) E. K. Warburton and B. A. Brown: Phys. Rev., C46,923 (1992).
3) D. J. Millener and D. Kurath: Nucl. Phys., A255, 315(1975).
4) S. Cohen and D. Kurath: ibid., 73, 1 (1965).
5) B. A. Brown, A. Etchegoyen, and W. D. M. Rae:OXBASH, MSU Cyclotron Laboratory Report, No. 524(1986).
6) H. Noya, A. Arima, and H. Horie: Suppl. of Prog. Theor.
Phys., No.8, p. 71 (1958).

RIKEN Accel. Prog. Rep. 28 (1995)

Asymmetry Parameter of 23Mg Beta Decay
K. Matsuta, M. Fukuda, S. Fukuda, T. Minamisono, Y. Nojiri, T. Izumikawa, M. Tanigaki, M. Nakazato,
M. Mihara, T. Onishi, T. Yamaguchi , T. Miyake, M. Sasaki, A. Harada, T. Ohtsubo, K. Yoshida,
A. Ozawa, T. Kobayashi, 1. Tanihata, J. R. Alonso, * G. F. Krebs, * and T. J. M. Symons*
NUCLEAR REACTION 197 Au + 24Mg, E = 91A MeV; measured {3-ray asymmetry of 23Mg,[ nuclear magnetic resonance; deduced asymmetry parameter of 23Mg ground state transition.
Study of the weak vector coupling constant G v for
mixed transitions provides a sharp test for the CVC(Conserved Vector Current) theory. The G v for amixed transition is obtained from the beta-decay asymmetry parameter in combination with the half life of
the transition. In the present experiment, the asymmetry parameter of 23 Mg beta decay has been measured
for the first time at RIKEN's K540 cyclotron using thetechnique of polarized radioactive nuclear beams.
The 23Mg nuclei were produced through projectile
fragmentation of the 24Mg beam bombarding a Au target at 100A MeV. The 23Mg fragments produced at adeflection angle of 2° were separated using the RIPS
(RIKEN Projectile Fragment Separator), and were momentum analyzed in the separator. Thus obtained polarized 23Mg nuclei were then implanted in a cooledthin Pt catcher foil placed in a strong magnetic field tomaintain the polarization. The polarization effect wasmeasured by means of asymmetric beta-ray emission
for both the ground state transition and the transition
to the first excited state. The transition to the excitedstate was tagged by the 440 ke V gamma rays.
Figure 1 shows the obtained beta-ray asymmetries
AP (A: asymmetry parameter, P: polarization) for
both beta-ray singles and beta-gamma coincidence
events. Since the value Aex is known to be - 0.6,
the ratio of two asymmetries, Aex/A~ = 0.90 ± 0.19,
gives asymmetry parameter for the ground transition
as Ao = -0.65(13), which is in good agreement withthe value -0.55 predicted from the CVC. More precise

23Mg

1

Beta-ray singles
,I

10

10
Runs

20

Fig. 1. Beta-ray asymmetries.

measurements are being planned in order to obtain the
coupling constant G v with the accuracy of about 1%.

LBL, Berkeley, U.S.A.

43

RI KEN Accel. Prog. Rep. 28 (1995)

Nuclear Moments of 179Ta
M. Wakasugi, W.-G. Jin, T. T. Inamura, T. Murayama, H. Katsuragawa,T. Ishizuka, J.-Z. Ruan, and I. Sugai[NUCLEAR MOMENTS (Static) 179Ta; measured a, b; deduced j,t, Q.]
We measured the hyperfine structure of radioactive
isotope 179Ta (T 1/2 = 1.8 y) with a laser spectroscopy
system using an argon-ion sputtering atomic beamsource. I) From the measurement, we determined magnetic dipole and electricquadrupole moments of the nuclear ground state.
A sample of 179Ta isotope was prepared by bombarding a natural Hf target (0.25 mm thick) with a 19 MeV
deuteron beam from an AVF cyclotron. Reactions of
180Hf(d,3n) and 179Hf(d,2n) were used. The number of
produced 179Ta atoms was about 5 x 1014 atoms. The
size of the d-beam spot on the Hf target was about 6
mm 2, and most of 179Ta atoms were mainly locatedat the depth shallower than 0.1 mm from the surface.
That means the abundance of 179Ta in a volume of 0.6
mm 3 was about 20 ppm.
After cooling of short lived isotopes such as 177Ta,
we set the radioactive sample together with a natural
Ta sample in the laser spectroscopy system. First, weobserved a hyperfine spectrum of a 540.3 nm transition from 4F3/2 ground state to 18504.7 cm- 1 4D1/2
state of the stable isotope 181Ta to check wavelengthof the laser and optimize geometrical conditions of theapparatus. The hyperfine spectrum is shown in Fig.
1(a). Next, we moved the sample so that the argonion beam hits the center of the d-beam spot on theradioactive sample. At this position, we measured thefluorescence spectrum at the same wavelength region
as in Fig. l(a) , and it is shown in Fig. 1(b).
To identify hyperfine transition lines of 179TaI, wemeasured a background spectrum with an argon-ion
beam by hitting a point outside of the d-beam spot
and the spectrum is shown in Fig. 1 (c). Then, hyperfine peaks of 179TaI have been identified as labeled by alphabets a to f in Fig. 1 (b). From thesepeaks, we could determine the hyperfine splitting of
the ground state 4F 3/ 2. Then hyperfine constants A
and B of the ground state 4F3/2 were determined to
be A 179 = 492(1) MHz, and B i79 = -1043(10) MHz.

44(a) 181Ta

l. 1. t ! Ja2(b) 179Ta

4

d
c

6

8

10

12

Relative frequency (GHz)
Fig. 1. Measured spectra of the 540.3 nm transition in
179Ta with reference spectra: The spectrum (a) was
obtained when an argon-ion beam hits the natural Ta
sample; the spectrum (b) was obtained for the center ofd-beam spot on the radioactive sample; and the spectrum (c) for a point outside the d-beam spot on theradioactive sample.

Since A factor is proportional to the nuclear magnetic
moment j,t, we derived the moment of 179Ta to bej,tf19 = +2.289(9) j,tN using A 181 and j,t f81 previously
known for 18 1Ta isotope. 2,3) A ratio of B factor of two
isotopes should be equal to the ratio of the nuclear
quadrupole moment Qs. The moment Q;79 of 179Ta
was also derived to be Q;79 = +3.37(4) b, using B 181
and Q;81 values. 2,3)
References
1) M. Wakasugi et al.: Rev. Sci. Instrum., 64, 3487 (1993).
2) W. G. Jin et al.: Phys. Rev., A50, 1920 (1994).
3) P. Raghavan: At. Data Nucl. Data Tables, 42, 189(1989).

RIKEN Accel. Prog. Rep. 28 (1995)

Nuclear Moments of 180mTa by Laser-RF Double-Resonance
Spectroscopy
W.-G. Jin, M. Wakasugi, T. T. Inamura, T. Murayama, H. Katsuragawa, T. Ishizuka, and 1. Sugai[NUCLEAR MOMENTS (Static) 180mTaj measured a, b; deduced J-L, Q.]
A typical refractory element Ta has a naturally occurring long-lived (T1 / 2 > 1.2x 10 15 y) spin (I = 9) isomer 180mTa at 75.3 keY, whose abundance is 0.0123%.
This exotic nuclide has attracted much interest in astrophysics as well as in nuclear structure physics. The
nuclear magnetic dipole moment of 180mTa was tentatively reported more than ten years ago 1) but the. electric quadrupole moment is not known.
We developed a laser-rf double-resonance (LRDR)
spectroscopic technique 2 ,3) using an innovative Ar-ion
sputtering atomic beam source especially to study refractory elements. 4 ,5) In this paper we shall reporta precise hyperfine structure (hfs) measurement of
180mTa by means of LRDR.
Figure 1 shows the laser-induced fluorescence spectrum of the 540.3 nm (ground state 4F3/2 - 18504.7
cm- 1 4D 1 / 2 ) transition. Six strong peaks are hyperfine transitions in 181Taj two small peaks indicated bya and f3 are those in 180mTa. The other hyperfine
transitions in 180mTa were masked by strong peaks of
181Ta.

.e

a

en
Q

$,.--.
~.~ xlOOO

8Q §.
8~

x1000
b

a

e

~

~
g~ ~~~~~~~~~--~--~--,-~!--,-~
::l

fi:

0

2

4

6

8

10

12

14

16

Relative Frequency (GHz)

Fig. 1. Laser-induced fluorescence spectrum of the 540.3
nm transition in Ta.

For the LRDR measurement of 180mTa, the laser frequency was fixed at one of hfs peaks, and change inthe fluorescence intensity as a function of the rf was
obtained by scanning the frequency applied to the rf
loop. The measured LRDR spectra for the peaks aand f3 are shown in Fig. 2(a) and (b), respectively.
From the LRDR spectra, two hyperfine splittings of/::..v(F-F' = 19/2-21/2) and /::..v(15/2-17/2) of 4 F3/2
in 180mTa were determined and thus the hfs constants

6300.-------------,

(a)
6100

.£
VJ

t=

~

~

...
:

~

•. .:,; {, ~5900 ;' ••i'".~"• "-,-•.• I.. '~.~:•••~

5700 L - - _ - - - - - J ' - - - _ - - - - '3336.23336.73337.2~ 4500 , . . . - - - - - - - - - - ,

.....

u

(b)

VJ

~

4300

,'f,.

&: 4100 A."'\,..",: J..~.:.
. : ,,'" . . .0.

~• • ,..,. . .

--:3900 L--_-----J'-----'------'
4318.84319.34319.8RF Frequency (MHz)Fig. 2. RF resonance spectrum (a) for F - F' = 19/2
- 21/2 and (b) for F - F' = 15/2 - 17/2 in 180mTa.
Spectrum (a) was measured for the optical transition Q:
in Fig. 1, and (b) for (3.

A and B were precisely derived for the ground state= 402.9466(10) MHz and B = -1533.056(15)MHz. Using the known hfs constants A and B 6 ) andnuclear moments J-L and Q7) for 181Ta, we have themagnetic dipole moment J-L180m = 4.825(11) J-LN and thespectroscopic quadrupole moment Q180m = 4.946(20)b for 180mTa. The present dipole moment is in agreement with that given by Burghardt et al. within theirexperimental error; 1) the present accuracy is improvedby a factor of five and the quadrupole moment wasdetermined for the first time.
4 F3 / 2 : A

References
1) B. Burghardt et al.: Phys. Lett., B92, 64 (1980).
2) W. G. Jin et al.: Phys. Rev., A50, 1920 (1994).
3) M. Wakasugi et al.: ibid., p. 4639.
4) M. Wakasugi et al.: Rev. Sci. Instrum., 64, 3487 (1993).
5) W. G. Jin et al.: Phys. Rev., A49, 762 (1994).
6) S. Biittgenbach and G. Meisel: Z. Phys., 244, 149(1971).
7) P. Raghavan: At. Data Nucl. Data Tables, 42, 189(1989).

45

RIKEN Accel. Prog. Rep. 28 (1995)

27 Al( d, 2He) Reaction Studied at Ed = 270 MeV
T. Niizeki, H. Ohnuma, T. Yamamoto, K. Katoh, T. Yamashita, Y. Hara, H. Okamura, H. Sakai, S. Ishida,
N. Sakamoto, H. Otsu, T. Wakasa, T. Uesaka, Y. Satou, S. Fujita, T. Ichihara, H. Orihara,
H. Toyokawa, K. Hat an aka , S. Kato, S. Kubono, and M. Yosoi[NUCLEAR REACTION 27 AI(d,2He), Ed = 270 MeV.]
We have been studying Gamow-Teller strength distributions in the T z = + 1 channel (G T +) for sd-shell
nuclei by (d, 2He) reactions. 1,2) In this report we
present the data on 27 AI. The experiment was carried out using a 270 MeV deuteron beam from the
RIKEN Ring Cyclotron and a large solid-angle, large
momentum-acceptance magnetic spectrometer system
SMART. The target was 39.4 mg/cm 2 thick selfsupporting foil of aluminum. Details of the experimentwere described in our previous reports. 1 ,2) Major modifications made since the report last year are the useof a helium gas-filled detector chamber and the use of
improved optics to further reduce multiple scatteringand to improve angular and energy resolutions. An
overall energy resolution of about 600 ke V has beenobtained so far.
Figure l(a) shows a sample small-angle spectrum
from the 27 AI(d,2He)27Mg reaction. This spectrum
was obtained by dividing a spectrum measured at the
spectrometer angle of 0° into smaller angular bins. The
peaks indicated by triangles show forward rise, and are
identified as being excited by GT transitions. In addition to those, there also seem to exist a number ofvery weak GT components in a high excitation energy
region. States in 27Mg that can be excited by GTtransitions should have J7r of 3/2+, 5/2+ and 7/2+.

200 ,---.----,------,-----,------,--r--~

5

+

.

~3

(b)

3/2 5/2 7/2 -

i

;:-4

j::"2
CJ

m1

References
-2

0

2

4

6

8

10

12

Excitaion Energy (MeV)

Fig. 1. Excitation energy spectrum (a) obtained at 0°
for the 27 AI(d,2He)27Mg reaction. Distribution of calculated reduced GT transition probabilities B(GT) is
shown in (b).
46

There is a 3/2+ state at 0.98 MeV in 27Mg, andtwo 5/2+ states at 1.70 and 1.94 MeV. 3 ) The 0.98
MeV state is strongly fed 4 ) by the f3 decay of the 5/2+
ground state of 27Na with a log it value of 4.3. These
low-lying states are only very weakly excited in the(d,2He) reaction. They are considered to be arising
basically from higher-seniority (d 5 / 2) 10 configurations
coupled with an S1/2 neutron. They should not therefore be excited by L = 0 in charge exchange reactions
on 27 AI, but should be strongly fed in the f3 decay of
27N a. Such an interpretation agrees with the experimental observation.
Major portion of the GT strength is concentrated in
two regions, one around 6 MeV and another around 9
Me V in excitation. The experimentally observed peaksin these regions look like composite peaks containing
several unresolved peaks. These peak shapes are a little broader than, but very similar to, those observed in
the 28Si(d,2He)28 Al reaction as discussed in a separate
report. 5 )Figure 1(b) shows the GT strength distribution
calculated for the full sd-shell configuration by the
OXBASH. 6 ) The B(GT) values are multiplied by 2J f +1, and the bin size is 200 ke V. Weak excitation of the
low-lying states discussed above agrees with the shellmodel calculation. The calculated G T strength distribution at least qualitatively reproduces the data: itgives two regions of concentrated strength separated
by about 3 MeV.
The A = 27 nuclei studied here are about the middleof the sd-shell, and expected to have numerous stateswith small GT components. Indeed there are 40 states
so far reported 3 ) between 4 and 8 MeV excitation energy in 27Mg, about three quarters of which have been
assigned to be 3/2+, 5/2+ or 7/2+. According to thepresent data, however, the GT strength in 27Mg is not
distributed over a wide region, but concentrated in narrow regions of excitation energy. Shell model calculations seem to be able to explain such concentration of
the GT strength. Further analysis is in progress .
1) T. Niizeki et al.: RIKEN Accel. Prog. Rep., 27, 38(1993), and references therein.
2) T. Niizeki et al.: Nucl. Phys., A577, 37c (1994).
3) P. Endt: ibid., A521, 1 (1990), and references therein.
4) D. Gullemaud-Mueller et al.: ibid., A426, 37 (1984).
5) T. Niizeki et al.: This report, p. 47.
6) B. A. Brown, A. Etchegoyen, W. D. M. Rae, and N. S.
Godwin: Program OXBASH (1984), unpublished.

RIKEN Accel. Prog. Rep. 28 (1995)

GT + Strength Distributions in N == 15 Isotones
T. Niizeki, H. Ohnuma, T. Yamamoto, K. Katoh, T. Yamashita, Y. Hara, H. Okamura, H. Sakai, S. Ishida,
N. Sakamoto, H. Otsu, T. Wakasa, T. Uesaka, Y. Satou, S. Fujita, T. Ichihara, H. Orihara,
H. Toyokawa, K. Hatanaka, S. Kato, S. Kubono, and M. Yosoi[NUCLEAR REACTIONS: 26Mg, 27 AI, 28Si(d,2He), Ed = 270 MeV.]
We have been studying Gamow-Teller strength distributions in the T z = 1 channel (GT +) for sd-shell
nuclei by (d, 2He) reactions. We have obtained, in particular, the (d,2He) spectra for the target nuclei 26Mg,
27 AI, and 28Si, all of which have N = 14. The final nuclei 26Na, 27Mg, and 28 Al are N = 15 isotones. Figure
1 shows spectra obtained at Blab = 0- 10 , the same asshown previously,I,2) except that those at Blab = 3- 40
have been subtracted after suitable normalization. The
L = 0 angular distributions are expected to decrease
rapidly from 0 0 to 40 , while those with higher L stayroughly constant in this range. Therefore the spectra
shown in Fig. 1 would be safely regarded as reasonable
representations of the GT + strength distributions infinal nuclei.

+

~ 150

~

d 100
~

c

50

:::l

8

0

I-----II~
- 18

3

~150
~

28Si(d,zHe)

r-: 100o........
~

c

50

:::l

8 0 W!N~""Fig. 1. Q-value spectra for the 26Mg, 27 AI, 28Si(d,2He)
reactions at Ed = 270 Me V obtained for the angularrange between 0 and 10. Those for 3- 4 0 have been
subtracted.

An interesting feature of these spectra is that all ofthem show quite similar distributions. There are only
two strong peaks in each spectrum; the one at lower excitation energy is the strongest, followed by a medium
peak 2- 3 MeV higher in excitation. There possibly areseveral other weaker peaks. The strongest peak in 28 Al

is known to have satellite peaks on both sides. 2) The Qvalues for the strongest peaks are about 11, 10, and 8
MeV for 26Na, 27Mg, and 28AI, respectively. The GT+
distribution observed in the 27 AI( d, 2He )27Mg reactionis broader than the others, because final states with J7r= 3/2+ , 5/2+, and 7/2+ can be excited by GT + transitions in this case, while only the 1+ states are excitedfrom even-even targets. An additional reason for abroader distribution in 27Mg may be the low neutron
separation energy of 6.4 MeV for this nucleus. The
strong GT peaks are well below the neutron thresholds in the other two cases.
Full sd-shell shell-model calculations have been successful to describe various properties of nuclei over theentire region of sd-shell. 3) Indeed the GT + strength
distribution in 26Na was found to be in reasonableagreement with the shell model prediction. 1) On theother hand, the GT _ distribution observed in the28Si(p,n)28p reaction 4 ) could not be reproduced by theshell model: the experimental data show that major
portion of the GT _ strength is concentrated in a few
peaks while the GT _ strength is spread over a wide
excitation energy region according to the shell model.
The 28Si( d, 2He) data shown in Fig. 1 are almost identical to those for the mirror 28Si(p,n) reaction, and disagree with the shell model calculation. Although theresults for 27Mg are somewhat uncertain due to thefact that there are more GT + states than in 26Na and
28 AI, the shell model calculations at least qualitatively
reproduce the data giving two regions of concentrated
GT strength. 2)
Wider spreading of the G T strength toward the middle of the sd-shell, as suggested by the shell model calculation, seems more natural since there are more s-dparticles and hence a wider configuration space available. However the present data combined with previous (p,n) data4 ) clearly show that this is not the casefor 28Si. The GT strength is concentrated in a few
peaks even at the middle of the shell. The reason forsuch failure of the shell model is not clear at present.
More detailed analysis of the experimental data andfurther theoretical investigations are under way.
References
1) T. Niizeki et al.: Nucl. Phys. , A577, 37c (1994).
2) T. Niizeki et al.: This report, p. 46.
3) B. A. Brown, A. Etchegoyen, W. D. M. Rae, and N. S.
Godwin: Program OXBASH (1984), unpublished.
4) B. D. Anderson et al.: Phys. Rev., C43, 50 (1991).

47

RIKEN Accel. Prog. Rep. 28 (1995)

Excitation of Spin-dipole States by the 12C(12C,12N)12B
Reaction at E / A = 135 Me V
T. Ichihara, M. Ishihara, H. Ohnuma, T. Niizeki, T. Yamashita, K. Katoh, S. Kubono,
M. Tanaka, Y. Fuchi, S. Takaku, H. Okamura, S. Ishida, and Y. Satou[NUCLEAR REACTION 12Ce2C,12N)12B, EjA = 135 MeV.]
Giant resonances can be described as the collective
motion of nucleons in a nucleus, or as coherent superpositions of one-particle one-hole excitations in a microscopic picture. Recent progress in shell-model theories has made it possible to carry out large-space microscopic calculations including 1 hw or even higher configurations for giant resonances in light nuclei such as
12C. Experimentally, charge-exchange reactions havebeen used extensively to reveal the isovector mode of
giant resonances. However, very little information has
been obtained about the spin-dipole resonances, which
are characterized by the quantum numbers b..S = 1,
b..T = 1 and b..L = 1.
Two broad peaks were observed at 4.5 MeV and 7.5
MeV in previous (p,n), (n,p) charge-exchange experiments on 12C.1) DWBA analysis of their angular distributions indicated that these peaks were dominantly
due to the J7r = 2- and 1- components, respectively.
They were interpreted as the members of the isovector spin-dipole resonance built on the ground state of
12C. In these reactions , however, both the spin-flip(b..S = 1) and non spin-flip (b..S = 0) components
can be excited.
The e 2C ,12 N) reaction has a stringent selectivity ofthe spin and isospin transfer, i.e. b..S = 1 and b..T = 1,
and can be utilized to pick up pure spin-flip components. It has been suggested that the e 2C ,12 N) reaction may become dominantly one-step in the regionof EjA > 100 MeV. Indeed our recent study of the
12Ce2C ,12N)12B reaction leading to the 12B groundstate (1 +) at E j A = 135 MeV has shown an encouraging result. 2) In this paper we extend such a spectroscopic study to the region of giant resonances.
The experiment was performed using an E j A =135 MeV 12C beam from the ring cyclotron at the
RIKEN Accelerator Research Facility. Outgoing particles were analyzed with the high-resolution spectrograph SMART. Figure 1 shows sample spectra at two
different angles. The 12B ground state (g.s.) as wellas the bumps around Ex = 4.5 MeV and 7.5 MeV arestrongly excited.
The deduced differential cross sections are plotted inFig. 2 together with the results of the microscopic onestep DWBA analysis using the Franey-Love t-matrices
and shell-model wave functions. 2)

48"C('2C. " N)I "s

100

Blab =

75

E/A = 135 MeV

0 . 1°_0 .2'"

50

50

100
50

U1LL~~~
o

10

20

30

40

50

Excitation Energy of I~ (MeV)

Fig. 1. Typical energy spectrum of the reaction.

(a)10-3 oLJ...L.J.-W....L.LJ...LJLo....w..-'-'-'-J...J...J...J(c)u....u...u...J..-,-,-,-u...w...L...1...J..-'-I...J....J2 8 •. . ( deg) em'-'--'--'---'--'--'---'--'---'-''-'--'--'---'--'--'--J...U...J

2 8 •.

m . (deg) eFig. 2. Differential cross sections for each state.

An intriguing feature observed here is that thestrength around 7.5 MeV comes mainly from the 2states. The discrepancy between the present analysis
and the previous (n,p) and (p,n) results 1) can be considered to be due to the different selection mechanismof the react ion. The ( 12 C ,12N) reaction selects only theb..S = 1 excitation whereas the (n,p) and (p,n) reactions involve both the b..S = 1 and b..S = 0 excitations.
References
1) X. Yang et al.: Phys. Rev. , C48, 1158 (1993) , and references theirin.
2) T . Ichihara et al.: Phys. Lett., 323, 278 (1994); Nucl.
Phys., A569, 287c (1994); ibid., A577, 93c (1994).

RIKEN Accel. Prog. Rep. 28 (1995)

Tensor Analyzing Power of the 12C(d,2He)12B Reaction
at 270 MeV
H. Okamura, S. Ishida, N. Sakamot o, H. Ot su, T. Uesaka, T. Wakasa, Y. Satou, S. Fujita, H. Sakai,
T. Ichihara, K. Hatanaka, T. Niizeki, K. Katoh, T. Yamashita, Y. Hara, and H. Ohnuma
NUCLEAR REACTION 12C(d, 2He), Ed=270 MeV, measured[ cross section and analyzing powers, DWBA analysis.
It is theoretically shown that the tensor analyzing
powers of the (d , 2He) reaction contain essentially thesame nuclear information as the polarization-transfer
observables of t he nucleon-nucleus scattering. 1) Considering its unique selectivities, ~S=l, ~T=l, and~Tz=+l , the (d, 2He) reaction should be a powerfultool for the study of t he spin-flip dipole state, particularly in identifying J7r of the residual nucleus (2- ,
1- , and 0- for a 0+ target). It would be fascinating toknow if the 0- collective states were enhanced throughtheir coupling to the pionic degrees of freedom in the

10 0
10- 1

10-

.•

1~xO.62

1

nucleus.
The usefulness of the tensor analyzing power, however, has not been experimentally established. We
have measured Ayy and Axx of the (d, 2He) reaction
at 270 MeV on the 12C target, the structure of which
is well understood. The cross section and the vector
analyzing power Ay have been also measured for the
study of the reaction mechanism. Details of the experimental procedure 2,3) and of the polarized deuteronbeam 4 ) are described elsewhere.
The result is shown in Figs. 1 and 2. The data has
been analy~ed according to the prior-formalism of the
DWBA theory for the three-body reaction. The calculation reproduces the data reasonably well. Details
are discussed in Ref. 3.
1.0
0 .15

A"

0.0
-0.15

- ::~ r+-+-+;rt+-+-+-+-t-+-+--+-t+-+-+-t::'t+-+-+-:-+-t=~~
10- 2

0 .11

A"" 0.0 ~;tk----if--­~en 10- 1

-0.11

-1.0

"..0

1.0

510-

0 .15

2

A ....

0.0 t-tr--+--r---t'----~+-0.11

c::"~.)Oo-1.0~~~~~~~~~~~~~~~~~~

o :> 10 15

b
'"d

10- 1

(dol) ....

..;;~~:;!!.

~

"~"

7 .5
.',
2;+4+~xO.6(dash)

1 ;+4+6 x O.6
(dot)

*.\.

", '

" ;~
....

>""

10-3~~~~~~~~o5 10 150

15 10 150

5 10 15'Scm (deg)0

5 10 150

5 10 15

Fig. 2. Angular distributions of the analyzing powers withthe result of DWBA analysis. The DWBA prediction
for the 0 4 state (Ex = 14 MeV) is also presented forcomparison.

4;:XO.~ ..

10 0

0

5 10 15 20
Bern (deg)Fig. 1. Angular distributions of the cross section. The
result of DWBA analysis is also presented normalized
by the factor indicated for each state.

References
1) D. V. Bugg and C. Wilkin: Nucl. Phys., A461, 575(1987).
2) H. Ohnuma et al.: Phys. Rev., C41, 648 (1993).
3) H. Okamura et al.: Nucl. Phys., A511, 89c (1994);
Phys. Lett., B345, 1 (1995); This report, p. 124.
4) H. Okamura et al.: AlP Conf. Proc., 293, 84 (1994);
This report, p. 148.

49

RIKEN Accel. Prog. Rep. 28 (1995)

Production of High-Spin Isomer BeamT. Kishida, S.-J. Chae, A. Ferragut, Y. Gono, E. Ideguchi, M. Ishihara, M. Kidera, J.-C. Kim, H. Kumagai,
H. Kusakari, G. Liu, B.-J. Min, S. Mitarai, T. Morikawa, K. Morita, T. Murakami, M. Nakajima, A. Odahara,
M. Ogawa, M. Oshima, M. Shibata, T. Shizuma, M. Sugawara, H. Tsuchida, A. Yoshida, and Y. Zhang
NUCLEAR REACTIONS, I60(136Xe,7n)145Sm, 9Bee70Er,Sn)174Hf, 27 AI( 130 Te,9n) I48Tb,[ Ep = 7-10 MeV /u, Recoil Separator, High-Spin Isomer Beams.
The high spin isomer beam line of RIKEN Accelerator Facility is a unique apparatus in the world. This
beam line provides a high spin isomer as a secondary
beam, which enables us to study the nuclear high spinstate of exotic condition. One of the important subjects is the search for off-yrast collective mode of thehigh spin isomer state by means of the Coulomb excitation. And another important subject is the productionof very high spin states by means of secondary fusion
reactions between the high spin isomer and the target
nucleus.
The high spin isomer beams are produced via heavyion-induced fusion reactions of inverse kinematics. The
fusion products, thus produced, recoil out into the forward direction and have large kinetic energies enoughfor the secondary reactions. In the first stage, a gasfilled system was used to enhance the secondary beam
intensity by the charge state equilibration of the beams
in the gas. I ,2) However, the effect of the multiple scattering in the beam line materials was too large to geta well- focused beam spot, and the beam transmission
was limited. In the second stage, in order to improve
the transmission, we developed a new system without filling gases and with the intermediate focal plane(F1) for the separation of the reaction products fromthe primary beam. 3) (See Fig. 1) As reported in Ref.
3, high spin isomer beams were produced via a Xeinduced reaction with, or without, filling gases, and

HP·Ge~7·SI..""
E1 C-COURSE at
RRC
Fig. 1. Schematic diagram of the high-spin isomer beamfacility.

50

1

the transmission without gases was measured to be
20-30% while that for the gas- filled system was about
10%.
In 1994, we produced three kinds of high spin isomer beams. (A) The high spin isomer of I45Sm of pI" =(49/2)+ was produced by the I60e36Xe,7n)145Sm reaction. A Si02 foil of about 2-3 mg/ cm 2 was used
as a production target. The primary beam intensity
was 6-30 x 109 sec- I . And the isomer yield was finally obtained to be about S x 104 sec- I by measuring
the known ,-ray yields. (B) The K-isomer of I74Hfof K7r = 8- was produced by the 9Be(170Er,Sn)174Hf
reaction. A Be foil of 1.84 mg/cm 2 was used as a production target, and the primary beam intensity was 612 x 109 sec-I. The isomer yield was, then, 1.5- 3 x 103
sec-I. The Coulomb excitation of the K-isomer state
was successfully observed with this beam. (C) The
high spin isomer of I48Tb of I = 274) was producedby the 27 Ale 30Te,9n)148Tb reaction. The data of thisexperiment is now in analysis.
In the case of I45Sm, we encountered the difficulties
that the production target would be destroyed by theheat emerged when the intensity of the primary beam
was very large. We, therefore, have to use a target
material like 9Be or 27 Al which has large heat conduc'tance. (For example, 145Sm can be produced by the9Be(1 42 Ce,6n)145S m reaction.)
Furthermore, we plan to use a gas target system asa production target for further increase of the primarybeam intensity. This high intensity high spin isomerbeam will be a powerful tool for secondary fusion experiments to produce a cold high spin compound nucleus.
References
1) Y. Gono et al.: RIKEN Accel. Prog. Rep., 26, 12 (1992).
2) Y. Gono et al.: Nucl. Phys., A557, 341c (1993).
3) T. Morikawa et al.: RIKEN Accel. Prog. Rep., 27, 31(1993).
4) The value of spin is preliminary.

RIKEN Accel. Prog. Rep. 28 (1995)

Coulomb Excitation of 174Hf K-Isomer: ,-Ray Spectroscopy
with High-Spin Isomer Beam
T. Morikawa, Y. Gono, K. Morita, T. Kishida, T. Murakami, E. Ideguchi, H. Kumagai, G. Liu, A. Ferragut,
A. Yoshida, Y. Zhang, M. Oshima, M. Sugawara, H. Kusakari, M. Ogawa, M. Nakajima, H. Tsuchida,
S. Mitarai, A. Odahara, M. Kidera, M. Shibata, J. C. Kim, S.-J. Chae, Y. Hatsukawa, and M. Ishihara

1

NUCLEAR REACTION, 9Bee 70Er,5n)17 4 Hf, Recoil Separator, High-Spin Isomer[ Beams, K-Isomer, Secondary Reaction, Coulomb Excitation, B(E2).
By using the high-spin isomer beam (HSIB),l) a
Coulomb excitation (COULEX) experiment of 174Hf
K7r = 8- isomer was successfully carried out. Thisis the first application of the HSIB to the I'-ray spectroscopy in the secondary reaction.
A 7.0 MeV /u 170Er primary beam was provided by
RIKEN Ring Cyclotron, and was incident on the production target of a 1.84 mg/cm 2 9Be foil with an intensity of 1- 2 pnA. The HSIB of 174Hf K-isomer was produced by the recoil separator system at E1C course,2)
and was delivered to the second target of a 208Pb foil of
2 mg/ cm 2. Due to the small difference of the magnetic
rigidity between the primary and secondary beams, theintensity of HSIB with reasonable purity was limited
to 1.5- 3 x 103 pps on the second target . Eight HP
Ge detectors at ()-y = 135° and four PPAC's covering 15° :::; ()p :::; 65° were used to detect COULEX
I'-rays and the scattered projectile, respectively, andthe coincidence signal between them triggered the dataacquisition system. Twenty-four NaI(Tl) scintillators

were also placed surrounding the PPAC chamber to detect the delayed I'-rays deexciting the isomer following
the prompt COULEX reaction.
The list-mode data were off-line sorted to extract the
COULEX events of 174Hfisomers. Figure l(a) shows aI'-ray spectrum obtained by the TOF (PPAC-RF) gate
for the reaction products. As a background, the 170Er(primary beam) COULEX spectrum was also made bya different TOF-gate as shown in Fig. l(b). The pure,-ray spectrum of 174Hf COULEX in Fig. l(c) was
finally obtained after the background subtraction. In
the I'-ray spectrum in Fig. l(c), the prominent peak ofg- -+ 8- transition was observed at 232 keY, as wellas the rotational sequence of the ground state band
(GSB) following the multiple-step excitation up to 8+
state. By gating on the NaI(TI) delayed signals, the232 keY transition was confirmed to feed the isomer. In
contrast, the 10- -+ 8- transition of fl.! = 2 was notobserved, which is consistent with the expectation for arotational band of a large K quantum number. Figure
2 summarizes the levels and transitions observed in thepresent experiment.
In order to estimate the B(E2 : 8- -+ 9-) value, weused the ratio of cross sections, 0-(8- -+ g-)/o-(ot -+Klt=8-, 2.4118
9-2028.0
25 0

100

200

300

400

Klt =6+, 133 n8500(b) BackGround

t

\~

l-.

I-

.:.i:

~15 0

~100

Us o

1::,

t
to

100

200

to
t
1:0
r..

300

400

174HfGSB

50

l-.

t

t

l-.
50

100

Gsa
8+

I

R
I.;

_21

:5

\, 8

1::,

N...JJ
tl r T''"K It=o+,1009.6500(c) BackGround·Subtracted00001549.3,

6+\,o J-.I~~~~,

50

7+'70ErGSB

>200
41

o

1737.4212
1797.5 i 8-

LA

!

941
1251

6+

+

3 1

t.,~

\,

~~

i

~L

200

I
*

to

300

10
t
1:0
400

297.517 4+500

Energy (keV)

Fig. 1. Doppler-corrected ,-ray spectra gated by 174Hf(a) and 170Er (b) components in the TOF (PPAC-RF)
distribution. The spectrum (c) is made by subtracting(b) from (a) with appropriate normalization.

91.0
0

t

2+
o~

;

174Hf

Fig. 2. A partial level scheme of 174Hf with the observed
transitions indicated by solid lines. Dashed arrows are
the transitions following the 174Hf K7T = 8- isomer
decay.
51

2t). The experimental value of this ratio was 0.57 ±
0.50, and is consistent with the theoretical value 0.51
which is calculated by assuming the K7r = 8- band as
a rigid rotor with Qo = 7.3 b,3) the same value as theground state. From the present analysis, B(E2 : 8- ---+
9-) value was extracted to be 2 ± 1 e 2 b 2 . Although theuncertainty is large, still it may be concluded that theK7r = 8- band has a collectivity as large as that of the
GSB. The goodness of the K-quantum number is alsosuggested by the absence of the 1::::.1 = 2 transition.
In the hafnium and tungsten region, some K-isomers
were recently reported 4 ,5) to severely violate the Kselection rule in their decay mode. In the case of 176W,
the K7r = 14+ isomer is reported 5 ) to decay directly to
the K7r = 0+ GSB member with a branching ratio of

52>30%, which clearly challenges our understanding forthe high-K isomers. It is, therefore, very important
to directly measure the B(E2) values and Q-momentsof the isomer bands by HSIB COULEX. Although thequality of the present data is not sufficient for suchan analysis, it is possible to improve it in the future
experiments.
References
1) Y. Gono et al.: Nucl. Phys., A557, c341 (1993).
2) T. Morikawa et al.: RIKEN Accel. Prog. Rep., 27, 31(1993) .
3) E. Browne: Nuclear Data Sheets, 62, 1 (1991).
4) N. L. Gj0rup et al.: private communication.
5) B. Crowell et al.: Phys. Rev. Lett., 72, 1164 (1994).

RIKEN Accel. Prog. Rep. 28 (1995)

High-Spin States in 148Tb
E. Ideguchi, Y. Gono, S. Mitarai, A. Odahara, M. Kidera, M. Sibata, M. Oshima, T . Morikawa, Y. Hatsukawa,
S. Hamada,* H. Iimura,* M. Shibata,* T. Ishii,* and T. Kishida[NUCLEAR REACTIONS, 141 Pr(13C,6n) 148 Tb, High-Spin Isomer Beams.]
The recent progress of the experimental teqniques
using unstable nuclear beams has made it possible tostudy nuclear structures in the extreme state which
was not attainable experimentally in the past. In order
to investigate extremely high-spin states of nuclei, thedevelopment of high-spin isomer beams 1) is going on at
RIKEN Ring Cyclotron. For the time being the available isomers as secondary beams are high-spin yrast
traps in N = 83 isotones 2- 7 ) and high-K isomers8) inthe Hf region.
In the N = 83 region the high-spin isomers were
found systematically. Figure 1 shows the systematicsof the high-spin isomer of N = 83 isotones. The excitation energies and half-lives of these high-spin isomers
are almost the same, i.e. ",,8 MeV and "" 1 J.Ls respectively. This suggests the resembling structure of theseyrast traps in the isotones. In these isotones 148Tb
is one of the candidates as a high-spin isomer beam
which can be produced by the 27 AI( 130 Te,9n) 148Tb reaction. The 27 Al target is easy to handle and resistantto heat up. In this reaction good separation of the reaction products from the primary beam is obtained since
the magnetic rigidity of their optimum charge states ismuch different. Therefore a detailed study to get the
information of the yrast trap of 148Tb was performed.

provided by the JAERI tandem accelerator. The selfsupporting 141 Pr foil target with the thickness of 4.7
mg/cm 2 was used. Six HPGe detectors with RIKEN
BGOACS's were used. The detectors were placed at
4 different angles with respect to the beam axis, sothat the information of the angular distribution and directional correlation (DCO) ratios could be obtained.
From the analysis of the excitation function and the,-, coincidence data a tentative level scheme was constructed up to the excitation energy of 11.8 MeV. And
the spin of each state was assigned by the analysis ofangular distribution of ,-rays. The half life of the highspin isomer was confirmed to be 1.1 J.LS by the analysisof the time spectrum between ,-rays. Figure 2 shows
the tentative level scheme so far constructed. The data
analysis is still in progress.

t IT I
~

~,

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a. '''lo"

(W )

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.-

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Sm

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147Gd

"8 Tb

"9

,.

Dy

Fig. 1. The systematics of high-spin isomers of N = 83
isotones.

Broda et al. 9) reported the low lying level scheme of
148Tb and a half life of the high-spin isomer as 1.1 J.LS.
But the decay scheme of the high-spin isomer was notestablished yet. The level structure above the highspin isomer was not studied either.
In order to clarify the level structure of 148Tb an
in-beam, experiment was carried out at the JAERI
tandem accelerater facility. The high-spin states of
148Tb were populated by the 141 Pr(13C,6n) 148 Tb reaction. The 13C beams of 95,98, 100 and 108 MeV wereJapan Atomic Energy Research Institute

.

~

""
.,o

Fig. 2. Tentative level scheme of 148Tb.

References
1) Y. Gono et al.: Nucl. Phys., A557, 341c (1993).
2) T. Murakami et al.: Z. Phys., A345 123 (1993).
3) A. Ferragut et al.: J. Phys. Soc. Jpn., 62, 3343 (1993).
4) A. Odahara et al.: Z. Phys., A350, 185 (1994).
5) E. Ideguchi et al.: Bull. Phys. Soc. Jpn., p. 108 (1993).
6) R. Broda et al.: Z. Phys., A305, 281 (1982).
7) O. Bakander et al.: Nucl. Phys., A389, 93 (1982) .
8) T. Morikawa et al.: submitted to Phys. Lett.
9) R. Broda et al.: Z. Phys., A293, 135 (1979).

53

RIKEN Accel. Prog. Rep. 28 (1995)

New Isomers in 174Hf
G. Liu, Y. Gono, T. Morikawa, E. Ideguchi , T. Kishida, K. Morita, H. Kumagai , A. Ferragut , A. Yoshida,
M. Ishihara, T. Murakami, Y. Zhang, M. Oshima, Y. Hatsukawa, M. Sugawara, H. Kusakari, M. Ogawa,
M. Nakajima, H. Tsuchida, S. Mitarai , A. Odahara, M. Kidera, M. Shibata, J.-C . Kim, and S.-J . Chae
[NUCLEAR REACTIONS 9Be(170Er, 5n)174Hf, 7.0 MeV lu, Measured E1" 11" ,,-coin.]
The N
106, Z
72 region is known to have
many multi-quasiparticle isomers. 1) Take the Z = 72
(Hafnium) isotopic chain as an example, the isomericstate with spin and parity as 22- in 176Hf, which corresponds to the 6 quasi-particle excitation, has been
observed. For 174Hf, however, only the isomer of
14+ has been obeserved; although the states built on
the 14+ isomer have been reported, they still remain
uncertain. 2) More experimental data are required tounderstand the high spin isomer states of 174Hf.
The experiment was performed on the E 1C highspin isomer beam (HSIB) course 3) of the RIKEN Ring
Cyclotron. The 174Hf was produced by the inversekinematic fusion reaction 9Be(170Er, 5n) 174 Hf at the
FO target chamber, with the energy of 170Er beam being 7.0 MeV lu and the 9Be target thickness being 1.84
mgl cm 2. The 174Hf was selected and then transported
to the F2 focal plane for measurement. The primarybeam and other reaction products were eliminated byadjusting the slit at the F1 focal plane. The ,-, coincidence measurement of 174Hf was carried out by using
two portable Ge detectors and one clover-type Ge with
4 units. 4) All the Ge detectors were calibrated with
152Eu and 133Ba ,-ray source.
The states built on the 14+ isomer have been reported with the first transition energy of 234 kev.1,2)
But such transition is not observed in our experiment.
Figure 1 shows the delayed, spectrum with timedifference condition of T 1-T 2 > 500 ns subtracted by
the spectrum with T1-T2 < -500 ns, and gated on
the transitions of K7r = 6+ band, which come fromthe decay of the 14+ isomer. There is no peak at 234
ke V; the inconsistency indicates that the band built on
the 14+ isomer still needs experimental data to confirm. Because the clover-type Ge detector was used in
the ,-, coincidence measurement , the Compton effect
f"-.J

54

f"-.J

becomes so serious that the background has many positive and negative bumps, and the real peak can beconcealed in the background. Further analysis of theexperimental data will be performed to eliminate such
effect.
2000
g Q).

<\I

1500

>CD 1000

-~
U)

c:

500

~.., ~

I ~ ~
II II

~'"

250

300

::s
0

0

200

350

Energy (keY)
Fig. 1. The delayed, spectrum gated by the transitionsof K7r = 6+ band, including 231 keY, 269 keY, 443 keY ,520 keY, 552 keY, and 569 keY (see for details in thetext). The positive peaks in the spectrum should be
attributed to the transitions above K7r = 14+ isomer
and the negative peaks to the transitions below K7r =6+ isomer.

References
1) P. M. Walker: Phys. Scripta, T5 , 29 (1983).
2) N. L. Gjorup et al.: Toronto Conf. , p. 160 (1992) .
3) T. Morikawa et al.: RIKEN Accel. Prog. Rep., 27, 31(1993).
4) Catalog of Eurisys Mesures, France, 1994.

RIKEN Accel. Prog. Rep. 28 (1995)

Excitation Energy of Hot Nuclei Produced in 40 Ar + 116S nReaction at E/ A == 30 and 37 MeV /u
K. Furutaka, K. Yoshida, A. Yajima,*1 Y. Akeboshi,*2 K. Matsuda,*2 T. Murakami, J. Kasagi,
T. Nakagawa, K. Yuasa-Nakagawa, Y. Futami, A. Galonsky, and G. Bizard
NUCLEAR REACTIONS: 40 Ar + 116Sn at E/A = 30,36.4 MeV /u; measured neutron, proton[ and a particle energy spectra and angular distributions; moving source analysis.
To determine excitation energies of hot nuclei
formed in heavy-ion fusion reaction and to study theirproperties, neutrons, protons and a particles emitted
in 40 Ar + 116Sn reactions at E/ A = 30 and 37 MeV /uwere measured in coincidence with heavy evaporation
residues (ER).
Self-supporting foil of 116Sn (about Img/cm 2) was
irradiated with 30 and 36.4 MeV /u 40 Ar beams of
about 15 enA served from the RIKEN Ring Cyclotron.
Neutrons were detected with 22 liquid scintillation
detectors placed between 30 and 155 deg. with respect to the beam axis and their energies 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 '"'( rays.
Protons and a particles were measured with BaF 2plastic phoswich detectors,1) in separate runs. Heavy
residues were detected with 4 stacks of MCP-MCP-Si
detector array placed !'VI0° with respect to the beamaxis and mass AER and velocity VER of evaporation
residues were deduced.
Events were divided into 4 bins according to VER
and examined separately. To deduce multiplicity Mi
and temperature parameter Ti , obtained spectra wereanalyzed using a Moving Source Model, in whichisotropic Maxwellian volume (surface) emission of neutrons (protons and a particles) was assumed. Twoemission sources were needed to reproduce the spectra: on,e is a pre-equilibrium-like source moving withroughly a half the beam velocity. The other is an equilibrium source moving with a similar velocity to VER .
From the obtained multiplicities and temperatureparameters for the equilibrium source, thermal excitation energy Eth was deduced using the following relation: Eth = Li=n,p,Q M i ( (Ei) + EC,i + B i ) + E"pwhere M i , (Ei ), EC,i, Bi are multiplicity, averageenergy, Coulomb energy and binding energy, respectively. E-y is the energy removed through '"'(-ray emission. (Ei) = 3/2Ti for neutrons, while for protons anda particles (Ei) = 2Ti'
In Fig. 1 the obtained excitation energies were plotted against R = Vobs/VFMT (bottom-up) together withenergies obtained by using a usual kinematical relation based on the massive transfer model 2-4 ) (topdown), where VFMT is the velocity corresponding to

1

full momentum transfer. As can be seen in the figure,the energy extracted by the present method is always
smaller than that calculated from the massive transfer
model, suggesting that in this incident energy region a
simple massive transfer picture is no more valid.
1000

-

I

800 ~

I

---:i

m'

I::

200 ...

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>Cl)

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1

R = V obsl~ ncr
Thermal excitation energies calculated using multiplicities and average energies (0) are plotted against R =Vobs /VFMT, together with those obtained by assuming
a simple massive transfer model (0).

References
1) Y. Futami et al.: Nucl. Instrum. Methods Phys. Res.,
A326, 513 (1993).
2) R. Wad a et al.: Phys. Rev., C39, 497 (1989).
3) A. Chbihi et al.: ibid., C43, 652 (1991).
4) K. Yoshida et al.: ibid., C46 , 961 (1992).

*1 Toshiba Electric, Co.
*2 Mitsubishi Electric, Co.
55

RIKEN Accel. Prog. Rep. 28 (1995)

Angular Momentum Dependence of the Giant Dipole
Resonance in Hot Nuclei
Y. Aoki, R. Sasaki, T. Ohtsuki, H. Yamazaki, J. Kasagi , K. Yuasa-Nakagawa, K. Furutaka, Y. Futami,
K. Yoshida, T . Nakagawa, and T. Suomijarvi*
Heavy ion fusion reaction, Finite temperature nuclei,[,. Giant dipole resonance, ,-ray multiplicity.
Our previous studies on the GDR in very hot nuclei 1 )show that there exists a limiting temperature of nuclei
for presence of GDR decay. In order to clarify themechanism of the disappearance of G D R in hot nuclei, information on the GDR in the excitaion energy
region between 150 and 200 MeV, especially on the
angular momentum and excitation energy dependenceof the resonance width, is very important. We haveinvestigated properties of decay ,-rays emitted from
nuclei at the excitation energy of about 150 MeV in
the Ni, 92Mo, 116Sn + 40 Ar reactions. Experiments
were performed at the RIKEN Ring Cyclotron. Selfsupporting foils were bombarded with 40 Ar beams at
E / A = 7 MeV. High energy ,-rays from the fusedcompound nuclei were detected with two sets of highenergy , -ray detector consisting of 7 BaF 2 scintillators which were placed at 90° and 135 0 with respect tothe beam direction at the distances of 15 cm from thetarget. In order to obtain a better detector response
for high energy ,-rays, a lead collimator was placed in
front of each detector, so that only the center scintillator was directly irradiated by the ,-rays from the target. The detector was covered by plastic scintillators
to reject events due to cosmic-rays. A BaF 2 ball covering about 1/3 of 47r with 62 plastic-BaF 2 phoswich
detectors 2) was used to measure low energy ,-rays andwas served as a ,-ray multiplicity filter to select the angular momentum brought into the fused nuclei. Since
light charged particles as well as ,-rays can be measured by the ball detectors, all the detectors are placedin a large scattering chamber (ASHRA), in order to obtain the correlation between the charged particle andthe high energy ,-ray emissions.
Events due to neutrons and charged particles were
rejected by the time-of-flight method together with apulse shape analysis. High energy ,-rays were measured in coincidence with as many as 14 low energy,-rays firing the ball detector. Spectra of high energy,-rays corresponding to the different spin regions wereobtained by setting a gate on observed distributionsof the number of detectors fired by ,-rays (M-y ). In
Fig. 1, 2, and 3, we show such spectra obtained in
the Ni + 40 Ar, 92Mo + 40 Ar, and 116S n + 40 Ar reactions, respectively; open circles are data for M-y = 4
and 5, triangles for M-y = 6 and 7, and squares for M-y~ 8. As shown, all the spectra show a bump on an
Institute de Physique Nuceaire,France56

IN2P3-CNRS , Orsay,

10 8

10 7

°

10 6

My = 4,5.. My = 6,7

0

My~ 8

20

22.5

10 5

~

~

10 4

.
10 3

10 2

10

5

7.5

10

12 .5

15

17.5

25

Ey

27 .5

30

(MeV)

Fig. 1. Gamma-ray spectra obtained in the Ni + 40 Ar reaction at E / A = 7 MeV. Open circles show the spectrum
for M')' = 4 and 5, triangles for M')' = 6 and 7, andsquares for M')' ~ 8.

10

5

7.5

10

12.5

15

17.5

Ey

20

22 .5

25

27.5

30

(MeV)

Fig. 2. Same as Fig. 1, except for spectra obtained in the
92Mo + 40 Ar reaction.

exponentially fall-off curve for E'Y > 10 MeV, which isinterpreted as arising from the decay of highly excitednuclei via GDR 'Y-ray emission. The high energy tailof the bump is less steep for the Ni + 40 Ar reaction
than for the other reactions. This observation is consitent with our understanding that the resonance energy
becomes larger as the mass number decreases. The resonance energy depends on spin as well; it seems to decrease as M'Y increases. In order to obtain the spin dependence of the resonance parameters quantitatively,
the analysis with a statistical decay calculation is now
in progress.

10·

116 Sn + 40 Ar (7MeVIA)
10o My = 4,5

7

L

"0

10 6

My = 6,7

o My? 8

000
00

"b

10

~

~

'b

10 4

'b........

~

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10

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22.5

References
1) K. Yoshidaet al.: Phys. Lett., B245, 7 (1990); J. Kasagi
and K. Yoshida: Nucl. Phys., A569, 195c (1994).
2) Y. Futami et al.: Nucl. Instrum. Methods Phys. Res.,
A326, 513 (1993).
25

27.5

30

(MeV)

Fig. 3. Same as Fig. 1, except for spectra obtained in the
116Sn + 40 Ar reaction.

57

RIKEN Accel. Prog. Rep. 28 (1995)

Development of Quasi-Monoenergetic Neutron Field with the Useof 80 to 135 MeV Protons Injected on Lithium
T. Nakamura, N. Nakao, M. Takada, E. Kim, M. Imamura, T. Shibata, Y. Uwamino, N. Nakanishi,
S. Fujita, S. Nakajima, T. Ichihara, and T. T. Inamura
quasi-monoenergetic neutrons, p-Li reaction, TOF method, organic liquid scintillator,
spallation cross section measurement.
Monoenergetic neutron fields are strongly needed forthe measurement of neutron reaction cross sections,
neutron penetration through matter, neutron detector
efficiency and so on, since these data in the energy
range above 20 MeV are quite poor. We developed
a quasi-monoenergetic neutron field in the E4 beamline of RRC. Ht -ions of 80, 90, 100, llO, 120, and 135
MeV /nudeon energies were injected on a 1-cm thick
7Li target to produce quasi-monoenergetic neutronsatdegrees with respect to the proton beam axis.
The neutron spectra were measured with a 12.7-cmdiam by 12.7-cm-long BC501A organic liquid scintillator placed 20 m away from the target. The spectra
given by the TOF method are shown for 90, 100, 110,
and 120 MeV proton energies in Fig. 1 and the lower
energy parts of the spectra in Fig. 1 were analyzed
by the unfolding method with the measured response
function. 1) The peak neutron energies and FWHMs are
86.3,96.5, 106.6, 116.7 MeV and 3.6, 3.3, 3.1 , 2.9 MeV,
respectively, for these four proton energies.
By irradiating these quasi-monoenergetic neutron beams, we measured the spallation cross sections of 12C(n,2nQ)7Be, 27 Al(n,spal)22Na, 7Be and209Bi(n,xn)210-xBi. The peak neutron fluence during
sample irradiation was determined from the 7Be yieldproduced in the target by 7Li(p,n) reaction. The activities induced in the samples were measured withan HP-Ge detector. We found many radioisotopes of
207Bi, which were produced by 209Bi(n,3n) reaction
down to 198Bi by 209Bi(n,12n), from the gamma-ray
spectra and are now analyzing the measured spectra inorder to get these cross section values from the reaction
rates of identified isotopes and the neutron fluence.

°

58

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Neutron Energy lMeVI

Fig. 1. Neutron spectra of 90, 100, 110, and 120 MeV p-Li
reactions.

References
1) T . Nakamura et al.: RIKEN Aceel. Prog. Rep., 27, 117(1993).

RIKEN Accel. Prog. Rep. 28 (1995)

Muon Catalyzed Fusion in Thin Deuterium Films and Slow
Negative Muon Production
P. Strasser, K. Ishida, S. Sakamoto,* K. Shimomura,* N. Kawamura,* and K. Nagamine[Muon Catalyzed Fusion, Thin Solid Hydrogen Films, Slow Negative Muon Production.]
Muon catalyzed fusion of deuteron/deuteron reaction (dd-j1CF) in thin deuterium films and slow negative muon emission l ) were investigated more intensively during the last experiment performed at the
TRIUMF superconducting muon channel.
Two different contributions to the total fusion yield,
i.e., one resulting from dJ.L atoms emitted from the primary H2/D2 layer via Ramsauer-Townsend effect andthe other through "direct" muon stopping in the D2
layer itself, were clearly distinguished in this last run.
This was realized by comparing results with a thindeuterium layer (~0.8 mg/cm 2) deposited directly on
the cold plate, and with those using the same deuterium layer thickness added to an ~8 mg/cm 2 H2/D2
layer (Cd ~10 - 3) (see Fig. 1). The ratio of "direct"
fusion versus fusion via emitted dJ.L was found to be
0.19(4) at this target thickness, for a total fusion yieldof 3.5(5) x 10- 4 per incident muons.
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been so successful at higher temperatures in terms ofhyperfine effects and muon molecular formation fromthermalized dj1, may be no longer adequate.
~120DT~~~~~~~~~~~~

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o

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80

:!J 40

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g

o
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0

100200300400500600

Time [ns]Fig. 2. Fusion proton time spectra with ~8 mg/cm 2 H2/D2(Cd ~ 0.001) EB ~0.82 mg/cm 2 D2 (open circles) andwith only ~0.82 mg/cm 2 D2 (closed circles).

Slow negative muon emission was also examined using an MCP detector. ~10-keV muons collected bya large-acceptance spectrometer were successfully detected at the expected time-of-flight depending on themagnetic field settings (see Fig. 3). These slow muons
are mainly produced by incident muons which are degraded through the target materials. The fusion yieldin the D2 layer being not sufficient enough, muons released after fusion can not yet be distinguished. It
seems that nearly one order of magnitude is needed to
identify the first slow muon re-emitted after dd-J.LCF.
This can be realized by increasing the incident muon
stopping number in the H2/D2 target, and by optimizing the D2 layer thickness to maximize the yield ofslow muons released from this layer.

Energy [MeV]Fig. 1. 88B energy spectra: (a) with only ~0.82 mg/cm 2
D 2, and (b) with ~8 mg/cm 2 H2/D 2 (Cd ~ 0.001) EB~0.82 mg/cm 2 D 2 .

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40

:!J

The fusion proton time spectrum obtained with thepure deuterium target (see Fig. 2) shows a similar resonance behavior to that observed with warmer targets,and suggests that the quartet state is still resonant.
However, the thermal energy of the target (3/2kT ~0.4 meV) is far too low to reach the lowest resonanceenergy of rv3 me V. An effective rate of molecular formation from F = 3/2 hyperfine state of 3.1(1.8) J.LS- l
and an effective hyperfine conversion rate of 36(15)J.LS- l were extracted. The statistics being not sufficientenough, it is nearly impossible to discuss quantitatively
these values. It is however close to the preliminary values obtained by Marshall et al. 2) with fusion neutrons
in a similar experiment. The interpretation of the results is at present not clear, and the analysis, which has

5 20

&

g
o

Z

200

400

600

800

Time [ns]Fig. 3. Measured MCP time spectra with ~8 mg/cm 2
H2/D2 (Cd ~ 0.001) EB ~0.34 mg/cm 2 D2: (a) 300
Gauss and (b) 400 Gauss.

References
1) K. Nagamine et al.: RIKEN Accel. Prog. Rep., 23, 69(1993).
2) G. M. Marshall et al.: Hyperfine Interact., 82, 529(1993).

Meson Science Laboratory, University of Tokyo

59

2. Atomic and Solid-State Physics

RIKEN Accel. Prog. Rep. 28 (1995)

Low-energy Electron Impact Ionization of Atomic Hydrogen
S. Watanabe and D. Kato*
Electron-impact ionization of hydrogen is one of themost fundamental processes involving one heavy andtwo light particles in disintegration without charge
Theory has been considered largely intransfer.
complete because theoretical methods could evaluatecross sections with a far less precision than can theexperiment. 1 ) Recently Bray and Stelbovics 2 ) have succeeded in bridging this long-standing gap from intermediate to high energies, however they left some gap
on the low-energy side unresolved. It is our purpose
to investigate the low-energy region rather close to thethreshold.
It has been found that the Hyper-Spherical CloseCoupling method (HSCC), developed by J. Z. Tang
et aI., 3) is applicable to the strongly correlated twoelectron atomic system. However the HSCC suffersfrom a fundamental problem, that is, its incapability
to represent the disintegration of the three-body system. In order to overcome this problem , we introduce
a matching procedure as follows.
Suppose we enclose the internal region with a large
enough box so as to contain all the dynamical information therein, and then project out the internal HSCC
solutions to the delimited asymptotic solutions which
satisfy the approximate Schrodinger equation,
1 2 1 2-1
- - E ) W~O( - -v\--\l222r2
where the effect beyond the monopole term is presumed negligible. Here let this box be a hypersphere ofradius Rm . At R > Rm we exclude the region where r2
is greater than r m = Rm / J2. This does not mean thatthe excluded region is entirely out of our consideration.
It would mean instead we construct wave packets byintegrating over suitable energy (or momentum) intervals so that the wave packets localized near the proton
are formed.
Figure 1 shows the total ionization cross section (jas well as (j / E, which is a more sensitive functionof correlations, calculated in the combination of the
HSCC with the matching procedure at energies up to
0.4 a.u. from the ionization threshold. The result iscompared with the other theoretical results 2 ,4) and the
Shah-Elliot-Gilbody experimental data. 1 ) The relative

(a)

o

0

0

+
(b)

o

0.2

0.4

E (a.u.)Fig. 1. (a) Total ionization cross sections. Solid line
represents present work, and open circles experimental data from Shah-Elliot-Gilbody,l) crosses the convergent close-coupling method ,2) and filled triangles thepseudo-state expansion method. 4 ) (b) a / E , a functionthat reveals the details near the threshold. Filled circles represent present work, and the other symbols are
as in (a) .

difference in (j between our result and the experimentis within a few % from E = 0.1 to 0.4 a.u. As forthe function (j / E , our result is smooth whereas theConvergent Close-Coupling (CCC) result of Bray andStelbovics 2 ) shows a noticeable fluctuation.
To conclude, we have succeeded in evaluating the
low-energy ionization cross section with a precisioncomparable to that of the Shah-Elliot-Gilbody experiment down to I"VO.l a.u. The adiabatic basis functions
adaptive to strong correlations should become progres- .
sively important for exploring even lower energy regions.
References
1) M. B. Shah, D. S. Elliott, and H. B. Gilbody: J. Phys.,B20, 3501 (1987).
2) I. Bray and A. T. Stelbovics: Phys. Rev. Lett., 70, 746(1993) and private communications (1994).
3) J. Z. Tang, S. Watanabe, and M. Matsuzawa: Phys.
Rev., A46, 2437 (1992).
4) J. Callaway: ibid., A44, 2192 (1991).

Department of Applied Physics and Chemistry, University
of Electro-Communications

61

RIKEN Accel. Prog. Rep. 28 (1995)

Mechanism of Enhancement of Some High-lying Resonance Seriesin Photoionization Spectra of Excited Helium
J .-Z. Tang and 1. Shimamura
The study of high-lying doubly excited resonancesof two-electron atoms is of fundamental and crucial
importance for our understanding of strong electronelectron correlations in atoms in general. Experimentson photoionization have advanced to the stage of resolving these resonances of helium up to the manifold
converging to the principal quantum number n = 6of the inner electron'!) Doubly excited states may begrouped into Rydberg series and these series may becharacterized in terms of a set of approximate quantum
numbers K, T, and A. Here, K and T are the quantum
numbers pertaining to the angular correlation, while A(= +1, -1, or 0, which are often abbreviated as +, -,or 0) pertains to the radial correlation. 2) Each member of these series may be specified by the notationn(K, T)~, with n' the principal quantum number ofthe outer electron. Another often used quantum number is v = (1/2)(n - 1 - K - T), which is the bending
vibrational quantum number of the three-body systemor the number of nodes in the angle (}12 between theposition vectors rl and r2 of the two electrons.
There exist nine (eleven) different 1po Rydberg series of He below the n = 5(6) threshold, of which
only one series with the ground angular mode, i.e.,v = 0, and with A = + was observed in the photoionization experiment. 1) To elucidate this experimental
finding, propensity rules, .6.v = 0 and .6.A = 0, were
proposed on the basis of the nodal structure of the
wave functions,3) which affects significantly the dipole
matrix elements. According to these rules, only Rydberg series of ground angular mode, v = 0, and with
A = + are populated dominantly for photoabsorption
by He(11S). However, the rules .6.v = 0 and .6.A = 0
have never been tested experimentally on photoionization from excited states of helium.
In the present work, the hyperspherical closecoupling (HSCC) method4 ) is used to compare thedetailed structures in the photoionization spectra ofHe(11S) and He*(21S) between the He+(n = 4) andHe+(n = 6) thresholds; both the total photoionization
cross section and partial cross sections for the production of He+ (n) are studied. Recall that the propensity rules were proposed on the basis of the correlation patterns or the nodal structures of the adiabatic
wave functions. The two initial states, He(11 S) andHe*(2 1S), have the same quantum numbers K = 0,
T = 0, n = 1, and v = 0 and the same property
A = +. Therefore the final states that are strongly
excited must be common to both processes according
to the propensity rule. 3) However, some doubly excitedresonance series of excited angular modes that are either weak or unobservable in the ground-state spectrum are found to be greatly enhanced in the He* (21 S)

62

spectrum. This corroborates that previously derived
propensity rules do not apply, in fact, to photoionization of He*(2 1S).
.The physical reason of this result lies in the dependence of the electron-electron correlation pattern on
the hyperradius R, which measures the size of the electron pair and is defined as R =ri + r~. The groundstate, He(11S), is deeply bound. Thus its wave function concentrates in the small R region, where the correlation pattern favors the dominant population of the
final state of the ground angular mode. This is consistent with the experimental findingl) and the propensity rule of Ref. 3. The metastable state, He*(2 1S),on the other hand, is loosely bound and a significant
portion of its wave function is concentrated in a largerR region, where the correlation pattern is so different
from that in the small-R region that the wave function may have a significant overlap with final Rydberg
states with v = 1 as well as those with v = O. This
interpretation also suggests the generality of the enhancement of some resonance series in excited-state
spectra.
Another effect of the electron-electron correlation in
the initial state on the photoionization process has
been observed in the partial cross sections 0"( n) forthe production of He+(n) ions. The calculated results
show that for photoionization of the ground-state helium, the n = 1 partial cross section 0"(1) is dominantly
large; while for photoionization of the metastable statehelium, the n = 2 and 3 partial cross sections are dominantly large. The large 0"(3) implies that the electronelectron correlation is important for the metastablestate He* (21 S) and that the independent-electron configuration 1828 is inadequate.
An interesting feature of high-lying doubly excitedresonance states is that the lowest one or more ofthose belonging to a series that converges to a threshold He+(n) may lie below the threshold He+(n - 1).
Thus, as perturbers, these resonance states may interfere strongly with doubly excited resonance states
belonging to the series that converge to the threshold
He+ (n - 1), resulting in overlapping resonances. Overlapping resonances near the n = 5 and 6 thresholds of
He + are studied and some resonances that are overlooked in the literature are uncovered. Details of thiswork have been published. 5 )viReferences
1) M. Domke et al.: Phys. Rev. Lett., 66, 1306 (1991).
2) C. D. Lin: Adv. At. Mol. Phys., 22, 77 (1986).
3) H. R. Sadeghpour: Phys. Rev., A43, 5821 (1991).
4) J.-Z. Tang et al.: ibid., A46, 2437 (1992).
5) J.-Z. Tang and 1. Shimamura: ibid., A50, 1321 (1994).

RIKEN Accel. Prog. Rep. 28 (1995)

High-lying Doubly Excited Resonancesin the Photodetachment of HJ .-Z. Tang and I. Shimamura
Doubly excited states of two-electron atomic systems, such as H-, He, and Li+, serve as prototypes
for unraveling the nature of strong electron-electron
correlations. Especially, those doubly excited states inwhich both electrons are highly excited exhibit theircharacteristic features. Recent high-resolution photoabsorption experiments have resolved clearly thesehigh-lying doubly excited states of both He l ) and H- .2)
Among the several computational methods for analyzing the detailed structures of these photoabsorption spectra, a hyperspherical close-coupling (HSCC)
method 3 ) has been particularly successful in reproducing the experimental photoionization spectra of He. 4 )A similar HSCC method combined with an analytic description of the wave function for the detached electronin the dipole field of excited hydrogen has been applied
to the photodetachment of H- in the energy regionof low-lying doubly excited resonances;5) the source ofthe discrepancy among previously calculated resonancespectra just above the threshold for the production of
the H atom in the n = 2 states has been clarified.
For a given total orbital angular momentum L , thetotal spin S, and parity 7r , each doubly excited state
may be labeled by a set of quantum numbers n{ v }~/,
or simply v;{/ when n is evident. The principal quantum number n is for the inner electron and n' is forthe outer electron. A pertains to the radial correlationand may be represented by +, - , or O. The bending vibrational quantum number v, representing the numberof nodes in the angle (h2 between the position vectors
rl and r2 of the two electrons, pertains to the angularcorrelation.
We extend the work of Ref. 5 for application to thephoto detachment spectra of H- involving high-lying
doubly excited states up to the H( n = 7) threshold.
In Fig. l(a), we show the calculated total cross section between the H(n = 5) and H(n = 6) thresholds.
We see that some resonances with A = - have also
clear presence in the spectra with relatively large amplitudes but very narrow widths. Thus the modification of the propensity rule of Ref. 6 that we found for
excited helium4 ) is necessary also for the ground stateof H- because it is only loosely bound.
The experimental partial cross sections 2 ) are compared in Fig. 1 (b) with the calculated ones for the production of H(n = 5) convoluted with the experimental
energy resolution of 8.3 meV; a good agreement is seen
over the whole spectrum. The narrow resonance 6{O}7"
has a sizable cross section even after the convolution
and is indeed observed in the experimental spectrumof Fig. 1 (b). Narrower resonances with A = - could

5.6
~

c::
o

5.5
5.4

t5

~ 0.10eneno

0 0 .05
0.00 1=I.:....------<---;"13-:::-1."=S5=--L..-..-----L.--'-----o1-:::'""3.J....".9-=5---'-.....1
Photon Energy (eV)Fig. 1. Photodetachment spectra of H- between the n = 5
and 6 thresholds. (a) The total cross section. The narrow high peaks are resonances with A = - . (b) The
partial one for the H(n = 5) production (solid curve:
convoluted with the experimental resolution of 8.3 meV j
circles: experiment. 2 ) The states are labelled by v~/.

be resolved clearly if the total photodetachment crosssections were measured with the same energy resolution.
Of particular interest among the calculated resonances are the Wannier ridge states n{O};t, whose energies with respect to the double-electron-ionizationthreshold may be represented by the formulaE(n, n) = -(Z - 0")2 j(n - J.l)2,(1)

where Z is the nuclear charge and the screening parameter 0" and the quantum defect J.l are parameterscharacteristic of the collective motion of the two electrons. We calculated and fitted the resonance energies
for H-, He, and Li+ to Eq. (1). The results show thatthe screening parameter 0" is independent of Z. The
quantum defect J.l is found to be approximately proportional to Z-l even though the Z values covered here
are as small as Z :::; 3.
References
1) M. Domke, G. Remmers, and G. Kaindl: Phys. Rev.
Lett., 66, 1306 (1992).
2) P. G. Harris et al.: ibid., 65, 309 (1990).
3) J.-Z. Tang, S. Watanabe, and M. Matsuzawa: Phys.
Rev., A46, 2437 (1992).
4) J.-Z. Tang and I. Shimamura: ibid., A50, 1321 (1994).
5) J.-Z. Tang et al.: ibid., A49 , 1021 (1994).
6) H. R. Sadeghpour and C. H. Greene: Phys. Rev. Lett.,
65 , 313 (1990).

63

RIKEN Accel. Prog. Rep. 28 (1995)

The Energy Relaxation of Subexcitation Electrons in H2 Gas
K. Kowari
Electrons with energies below the lowest electronic
excitation threshold energy of the constituent moleculeof a gas relax owing to elastic collisions, vibrationallyinelastic collisions, rotationally inelastic collisions, andchemically reactive processes such as the electron attachment. These electrons are termed subexcitationelectrons. The constituent molecules of a gas are taken
to be in large excess. In previous papers,1,2) we havecarried out the time-dependent studies on the degradation and thermalization of the subexcitation electrons in CH 41) and SiH42) with the method developed
by Kowari et al.l) The method is based on the Boltzmann equation with the Fokker-Planck operator forelastic collisions and a difference operator for inelastic
collisions.
Thermalization and degradation of subexcitationelectrons with initial energies of 1 eV, 3 eV and 5 eV
in H2 gas at a pressure of 1 atm and temperature of
300 K are studied with the numerical solutions of the
Boltzmann equation. The collision term of the Boltzmann equation has the elastic term and inelastic term
involving rotationally inelastic collisions as well as vibrationally inelastic collisions.
Figure 1 shows thermalization time with the initialenergies of 1 eV. The solid curve represents the thermalization time which shows a change of the averageenergy of electrons obtained from the Boltzmann equation, and the dotted curve expresses the continuousslowing-down approximation (CSDA) time. The thermalization time and CSDA time show a moderateagreement as a whole, and they agree very well in ashort time range and deviate in a long time range.
The details of the present study will be describedin Ref. 3. We give the summary on the details of
the study as follows. Time evolution of the electron density distribution function , that of the cumulative degradation spectrum, and thermalization
times are obtained. Time-dependent yields or col-

64

20
..c

ur
-; 15
co

ill

10
5
OL-~~~~~~~~~~-~~

10-3

10-2

10-1

100

10 1

t (ns)
Fig. 1. The thermalization of the average electron energy in H2 at 300 K; the initial electron energy in electron-volts is equal to 1. The dashed curve is the CSDA
time.

lision numbers for rotationally and vibrationally inelastic processes are calculated by using the cumulative degradation spectrum. We extensively discuss thepresent thermalization times in comparison with experimental thermalization' times and other theoreticalvalues.
References
1) K. Kowari, L. Demeio, and B. Shizgal: J. Chern. Phys.,
97, 2061 (1992).
2) K. Kowari and B. Shizgal: Chern. Phys. , 185, 1 (1994).
3) K. Kowari: to be published in Phys. Rev. , A.

RIKEN Accel. Prog. Rep. 28 (1995)

Single and Double Ionization of Heliumby Slow Protons and Antiprotons
M. Kimura, I. Shimamura, and M. Inokuti*
The first series of atomic collision experiments using
an antiproton (p) beam of energy above 0.5 MeV wascarried out in the low-energy antiproton ring (LEAR)
at CERN. I ) In these experiments, the ratio Ra(P) =(]"++ / (]"+ between double- and single-ionization crosssections (]"++ and (]"+ of He for P impact was foundto be larger by a factor of two than that for proton(p) impact, Ra (P). Some theoretical attempts havebeen made to understand the conspicuous difference
between p-impact and p-impact double ionization. 2- 5 )The studies have shed light on the limitations of the
independent-particle model and on the importance ofelectron correlation in these processes.
The recent upgrade in the LEAR facility has led
to experiments by Hvelplund et a1. 6 ) in a much lower
energy regime down to 10 keV; see Fig. 1. The ratio Ra (p) decreased sharply as the energy decreased,
while Ra (p) increased nearly monotonically. At 20
ke V, Ra (p) was larger than Ra (p) by an order of magnitude.

rP

o ~ o

o

10. 4

to

00

o 0

0

o

0:

•

0 0

°0

•

ji : Theory

00

°

•

p: TheoryD

p: Hvelplund et ai,

E (keV)

Fig. 1. Ratio of double to single ionization cross sections
due to rr and p..impact. Theoretical results are fromthe present work. The experimental results are takenfrom Ref. 7 for p impact and from Ref. 6 for jj impact.

Here we report the results of our investigation of
double and single ionization for p and p impact on
the basis of a semiclassical molecular-state expansion method. In this method, the electronic motion
is described quantum mechanically as a two-centermolecular-state problem, and the relative motion between the two heavy particles is described classical mechanically. Discrete molecular electronic states were
determined by the configuration-interaction methodwith the use of Slater-type orbitals as basis functions.
Singly ionized continuum electronic states were obtained in the fixed-nuclei static-exchange approximaArgonne National Lab., U.S.A.

tion for elastic electron scattering from the neutral
molecule pHe+ or the molecular ion (HeH)++. Thosefor doubly ionized states were constructed by using
a perturbation method in which the interelectronic
Coulomb potential is the perturbation and the terms
up to the first order in the wave function are retained.
The adiabatic wave-packet approach, which spans electronic continuum locally, was taken. A discretizedsampling procedure, based on the Gauss quadrature,
was used to select continuum states for the molecularstate expansion method. The number of channels included in the calculations was 150-250.
Figure 1 displays the present results for Ra alongwith the measurements for j5 impact by Hvelplund etal. 6) and for p impact by Shah and Gilbody.7) Good
qualitative agreement between the theoretical and experimental results is seen. The present results clearly
exhibit characteristic features of the increase and decrease in the ratios Ra for p and p impact with decreasing energies. We examined details of each ionization probability (as a function of the impact parameterand the energy of the ejected electons), obtained fromvarious test calculations. The presence of the positive
charge deforms the electron cloud of He toward theincoming proton for charge transfer, and on further
approach of the proton, some fractions of these electron distributions subsequently lead to single or double
ionization by ladder-climbing the molecular states. For
p impact, in contrast, the deformation of the electron
cloud is in the opposite direction and the electronicbinding energies decrease, which is the main mechanism for single ionization. The electron-electron interaction in the presence of p is of primary importancein the emission of another electron, leading to double
ionization.
Details of this work were published elsewhere. 8)
References
1) L. H. Andersen et al.: Phys. Rev. Lett., 57, 2147 (1986);
Phys. Rev., A36, 3612 (1987); ibid., A40, 7366 (1989).
2) H. Knudsen and J. F. Reading: Phys. Rept., 212, 107(1992).
3) L. Ford and J. F. Reading: J. Phys., B21, L685 (1988);
ibid., B23, 2567; 3131 (1990).
4) J. McGuire: Phys. Rev. Lett., 49, 1153 (1982).
5) D. R. Schultz, R. E. Olson, and C. O. Reinhold: J.
Phys., B24, 521 (1991).
6) P. Hvelplund et al.: ibid., B27, 925 (1994).
7) M. B. Shah and H. B. Gilbody: ibid., B22, 3037; 3983
(1989).
8) M. Kimura, I. Shimamura, and M. Inokuti: Phys. Rev.,
A49, R4281 (1994).

65

RIKEN Accel. Prog. Rep. 28 (1995)

Ionization and Charge Transfer of Atomic Hydrogen in Collision
with Multiply Charged Ions
N. Toshima
The close-coupling method has been widely used invarious fields of atomic collision physics with the recognition that it is one of the most reliable and powerfultheoretical approaches. It is mostly applied to scattering processes in the intermediate or low energy region,
where the multiple scattering effect is so significant
that perturbative approaches are not applicable. Although good agreement has been achieved with experimental data for various excitation and electron capture processes, extensive study of ionization processes
has not been performed so far. The contribution of thecontinuum states is usually taken into account throughdiscretized continuum states constructed by the diagonalization of the target and projectile Hamiltonians
in terms of a set of square integrable basis functions.
The purpose of inclusion of pseudo continuum stateshas been in most cases to improve the description of
the two-center nature of the electronic wave functions ,and hence a sufficiently large number of positive-energy
pseudostates have not been employed for the calculation of ionization cross sections.
Though the Slater-type orbitals have been mostly
used for the construction of basis functions of the
expansion, the existence of the electron translation
factor (ETF), which accounts for the different translational motion of the two nuclei, makes impossible
the analytic evaluation of the two-center matrix elements. Accurate numerical evaluation of the matrix
elements becomes rather difficult when the collisionenergy is high owing to the rapid oscillation of ETF
or when the states have many nodal structures. In
the study of the Thomas mechanism, Toshima andEichler 1 ) have avoided the difficulty in the numericalintegration of the matrix elements by the introductionof the Gaussian-type orbitals (GTO) for the expansion. The GTO representation enables all the twocenter matrix elements to be evaluated analyticallywith any desired accuracy regardless of the collisionenergy. It was demonstrated that the GTO representation is a very powerful method for the treatment of
the processes in which continuum states playa decisive role. Most of the existing theoretical calculationsof ionization cross sections of atomic hydrogen in collision with multiply-charged ions are based on perturbative approaches and their agreement with experimental
data is not satisfactory at intermediate and low energy regions. 2) Toshima3 ) investigated the ionization
process in C 6 + + H collisions by the above-mentioned
close-coupling method and he found that deep boundstates of the projectile ion have a significant contri-66

but ion to the ionization and excitation cross sections
below 10 keY and the neglect of those states causes
serious overestimation of the cross sections.
In this report we calculate ionization and electron
capture cross sections for the collisions of atomic hydrogen with multiply-charged naked ions of the nuclear
charges Z = 2- 8,
AZ+ + H(ls)

--+
--+

AZ+ + p + e
A(Z - l )++p

by means of the close-coupling method based on theGaussian-type-orbital expansion.
The numbers ofGaussian-type orbitals and the ranges of the non-linear
parameters are determined and optimized so as to produce the wave functions of all the bound states sufficiently accurately. With increasing the Gaussian orbitals still further, the eigenvalues of the pseudocontinuum states shift to lower energies as a whole andthe spacings among them become smaller but the calculated ionization cross sections change little. The capture cross sections show more rapid convergence withincreasing the number of Gaussian orbitals.
The contribution of the projectile continuum to theionization is generally smaller than that of the target
continuum and they show different dependence on theimpact parameter. The impact parameter dependenceof the ionization to the target continuum has resemblance to that of the excitation regardless of the collision energy while the ionization to the projectile continuum shows rather different behavior from that of theelectron capture at low energies. The present calculations give ionization cross sections of atomic hydrogensystematically in good agreement with experimental
data for various projectile charges in a wide energy
range covering from the adiabatic transition region to
the perturbative high-energy region. Simultaneously
they produce highly reliable cross sections for excitation and electron capture. The details of the results
are presented in a separate paper. 4 )References
1) N. Toshima and J. Eichler: Phys. Rev. Lett., 66, 1050
(1991); Phys. Rev., A46, 2564 (1992); N. Toshima: 1.
Phys., B26, L281 (1993).
2) M. B. Shah and H. B. Gilbody: J. Phys., B16, L449
(1983).
3) N. Toshima: ibid., B27, L49 (1994).
4) N. Toshima: Phys. Rev., A50, 3940 (1994).

RIKEN Accel. Prog. Rep. 28 (1995)

Magnetization of Ferromagnetic Clusters
G. Bertsch,* N. Onishi, and K. Yabana**
Dynamics of small clusters, composed of a ferromagnetic material like iron, in the magnetic field of a SternGerlach magnet (SG) has been studied experimentally
through observations of the deflection profile. 1- 4 ) The
angular momentum of clusters is dominantly carriedby nuclei constituting clusters. The relative motion of
nuclei occuring in shape oscillation, is not expected to
be important, and hence clusters may be considered tobehave as a rigid-body. On the other hand, the magnetic moment of clusters coupled with the magnetic
field, is due to the electron spin polarized to a certain
direction. The coupling of the total electron spin witha rigid body is assumed to be so strong that the direction of spin polarization of electrons is frozen along an
axis of the rigid-body.5-7)
The dynamics is studied in classical mechanics. It
is justified that, because the moment of inertia is extremely large, highly excited states of large angularmomentum are populated at temperature of the beamsource. Therefore the unit of angular momentum 1i isvanishingly small. An advantage of the analysis of the
motion in terms of classical mechanics is to understandthe associated dynamics more clearly and intuitively.
We treat a simple case of an axially symmetric rotor
in which the direction of magnetization is along thesymmetry axis. The density of clusters in the beam isconsidered to be also small enough that they are isolated. For an isolated system of the simple model, thedynamical variables are separated into rotation, precession and nutation, and the motion is solved completely in analytic form.8)
The variation of magnetic field, which takes placein entering into a SG magnet, is assumed to be smallenough. in comparison with a typical period of the motions; this is called the adiabatic assumption. In theassumption, an adiabatic invariance for the nutation

is found, which relates the total angular momentum
conserved outside of the magnet to the total energy inthe magnet through adiabatic continuation. We derivea scaling law in which the magnetization and the deflection profile are functions of the magnetic field andthe temperature only through the ratio of the magnetic field strength to the temperature /-LoB / kBT likein the Langevin formula of magnetization in the canonical ensemble. This scaling law implies that the model
has not any structure giving a characteristic scale forenergy and angular momentum. We also discuss two
limits of weak-field and/or high-temperature and viceversa.
Our results reveal that a simple model such as arigid-body with frozen electron spin is not able to explain the experimental data; the magnetization curve
versus magnetic field strength has a dip at high temperature. Now we are working on an intermediate coupling model of electron spin with a rigid-rotor. The
strength of coupling gives a certain temperature atwhich the structure change takes place in magnetization, and the scaling law may be violated.
References
1) D. M. Cox et al.: Phys. Rev., B32, 7290 (1985).
2) W. de Heer, P. Milani, and A. Chatelain: Phys. Rev.
Lett., 65, 488 (1990).
3) J. P. Bucher, D. C. Douglass, and L. A. Bloomfield:
ibid., 66, 3052 (1991).
4) I. Billas, J. Becker, and W. de Heer: Z. Phys., D26, 325(1993).
5) P. J. Jensen and K. H. Bennemann: ibid., p. 246.
6) A. Maiti and L. M. Falicov: Phys. Rev., B48, 13596(1993).
7) G. F. Bertsch and K. Yabana: ibid., A49, 1930 (1994).
8) H. Goldstein: in Classical Mechanics, Addison-Wesley,p. 213 (1981).

Institute for Theoretical Nuclear Physics, University ofWashington
Faculty of Science, Niigata University

67

RIKEN Accel. Prog. Rep. 28 (1995)

Lifetimes of the 3p 2p Levels of Na-like Nb
R. Hutton, S. Huldt , B. Nystrom, I. Martinson, K. Ando,
T. Kambara, Y. Kanai, Y. Nakai, and Y. Awaya
We have used the techniques of beam-foil spectroscopy to investigate the atomic structure of Na-like
Nb. The lifetimes of the 3p 2p levels have been investigated using the ANDC (Arbitrary Normalized Decay
Curve) method of cascade correction. This was shown
to be essential in a previous beam-foil study1) of 3p 2p
lifetimes for Na-like Ti, Fe, Ni, and Cu. The measurements presented here bridge the gap between the oldwork up to Na-like Cu and newer data from Trabert
et al. for Na-like Xe and Au. 2)
The experiments were done using a beam of 183 MeV
Nb ions provided by the RILAC. Details of the experimental setup can be found in Ando et al. 3) The beamfoil spectra of Nb showed the 3s 2S - 3p 2P1/2,3/2 resonance doublets, at 135.1 A and 182.7 A, as well as
the 3p 2p - 3d 2D lines at 109.57 A and 131.69 A.
A section of the spectrum is shown in Fig. 1. The
decay curves of the four Nb lines were measured carefully. Examples of the decay curves are shown in Fig.
2. As demonstrated earlier,l) cascading from 3d levels
to 3p levels must be corrected for , to avoid systematic errors in the 3p lifetime values. This was accomplished by using the ANDC method of Curtis et al. 4 )which is based on joint analysis of the decay curves ofthe primary level (the lifetime which is to be deter-

2000 W
11

1000

I

134

136

138

Wavelength (.A)

Fig. 1. This figure shows a small wavelength region of abeam-foil spectrum recorded for 183 MeV Nb.

68

10

12

Di s tan c e (m m )Fig. 2. Decay curves for the 3s 2S 1 / 2 - 3p 2P3/ 2 and3p 2P 3/ 2 - 3d 2Ds / 2 transitions in Na-like Nb.

mined) and of the levels t hat feed it. In the present
work the ANDC analysis was performed by means of
the CANDY computer code. 5 ) The lifet ime values obtained in this way are t = 29 ± 2 ps for the 3p 2P3/2
level and t = 70±5 ps for the 3p 2P1/2. These data arein excellent agreement with the theoretical values ,6)
which are 28.55 ps and 68.77 ps for these levels.
References

3000

f~

o

1) R. Hutton, L. Engstrom, and E . Thibert: Phys. Rev.
Lett. , 60, 2469 (1988) .
2) E. Thibert , J. Doerfert, J. Granzow, R. Buttner, U.
Staude, K . H. Schartner, P. Rymuza, P. H. Mokler,
L. Engstrom, and R. Hutton: Phys. Lett., A188, 355(1994).
3) K. Ando et al.: J. Spectr. Soc. Jpn. , 41 , 370 (1992).
4) L. J. Curtis, H. G. Berry, and J. Bromander: Phys.
Lett. , A34, 169 (1971).
5) L. Engstrom: Nucl. Instrum. Methods, 202, 369 (1982).
6) C. E. Theodosiou and L. J. Curtis: Phys. Rev., A38 ,4435 (1988).

RIKEN Accel. Prog. Rep. 28 (1995)

Mg-like Intercombination Lifetimes for Zr and Nb
R. Hutton, S. Huldt, B. Nystrom, I. Martinson, K. Ando,
T. Kambara, Y. Kanai, Y. Nakai, and Y. Awaya
Intercombination (spin-forbidden) transitions suchas the 3s2 ISo-3s3p 3Pl line in Mg-like ions are of considerable interest in plasma diagnostics. For instance,
the ratio of the intensities of close-lying allowed andspin-forbidden lines can be used to determine electron
densities in plasmas. Also, calculation of these intercombination rates requires careful treatment of several
factors, e.g., configuration mixing, spin-orbit interaction and relativistic effects.
In this work beam-foil studies were made for Mglike Nb and also for the neighboring element Zr. In
the latter case two isotopes, 90Zr and 9l Zr , were investigated with the aim of searching for possible nuclearspin induced effects on the decay of the 3s3p 3P 1 level.
The beam-foil setup is described in Ando et al. l ) Because of their comparatively long lifetimes the intercombination lines are often weak features in complex
spectra or even masked by stronger, allowed transitions. One of the unique properties of the beam-foil
method is that time-delayed spectra2 ) (recorded at a
certain distance downstream from the foil) can be obtained. This feature can be used to enhance lines fromlong-lived levels. We used this property to identify
the 3s 2 ISO - 3s3p 3P 1 line in the Zr and Nb spectra.
60 r-----~------~------~------~------~DELAYED SPEC , 183 MeV Nb
50

Such a spectrum for Nb is depicted in Fig. 1. The
Mg-like intercombination line can be seen at 197.7 A.
Figure 2 shows decay curves measured for this transition both with and without a small (6 gauss) magnetic
field to diverge beam related electrons; see Hutton eta1. 3 ) The values we find for the lifetime of the 3s3p 3P llevels in both Zr and Nb are about 20% shorter thancurrent theoretical values (e.g., Huang and Johnson4»)
This discrepancy is the subject of further experimental
and theoretical investigation.
lOOOOr-------.--------.-------...,..-------...----------.

3s3p 3p,
100

Nb 29+

10

2

3Time after excitation (ns)Fig. 2. Decay curve for the 3s 2 ISO - 3s3p 3P 1 transition
for Mg-like Nb recorded at a beam energy of 183 MeV.
(a) Background decay (i.e., a decay curve taken in theposition of no apparent line), (b) a decay curve takenwith no magnetic field, and (c) a decay curve taken witha magnetic field to remove beam-related electrons.

40)0References20

10~9~0------~------2~00-------2~05-------2~'0

Wavelenglh . A

Fig. 1. Delayed spectrum for 2 MeV/nucleon Nb ions after
foil excitation. The 3s 2 ISO -3s3p 3P 1 intercombinationline is at 197.68 A.

1) K. Ando et al.: J. Spectr. Soc. Jpn., 41, 370 (1992).
2) E. Trabert: Physica Scripta, 48, 699 (1993) and references therein.
3) R. Hutton et al.: Proc. Int. Conf. on the Physics ofHighly Charged Ions (HeI), Vienna 1994. To be published in Nucl. Instrum. Methods Phys. Res.
4) K. N. Huang and W. R. Johnson: Nucl. Instrum. Methods Phys. Res., B9, 502 (1985).

69

RIKEN Accel. Prog. Rep. 28 (1995)

Beam-Foil Spectra of Highly Charged Neon
K. Ishii, Y. Kimura, T. Nishida, and K. AndoIn this report we present the results of a beamfoil study of the spectra of highly charged neon ionsin the visible and near UV regions. The spectra of
NeVI-NeIX have been thus far studied in the VUVregion. 1-5) The beam-foil method is efficient for populating states with high nand l quantum numbers inhighly charged ions. The excited states thus createddecay radiatively with emission of visible and near UV
photons as well as VUV ones. The observation of thetransition makes it possible to establish the high lying
energy levels and to estimate the ionization potentials.
This method has been used extensively; see e.g. Ref. 6
for chlorine, Ref. 7 for oxygen, and Ref. 8 for fluorine.
Neon beams at the energy of 10 MeV from RILAC weresent through a thin carbon foil with a thickness of 10
f..tg/cm 2 . The photon emission of the post foil beams
was observed in perpendicular direction to the beam,by use of a monochromator (NIKON G-250) and a photomultiplier (Hamamatsu R585) in conjunction withthe standard NIM modules. The photoelectron pulses
were stored in a microcomputer together with the integrated beam current and the clock signals. The whole
spectrum was recorded between 3000A and 6000A witha slit width of 0.5 mm. The partial spectrum recordedwith higher resolution by refocusing the monochromator and by narrowing the slit width, is displayed inFig. 1,.....Vl 2000
C
:::l

o

U

Wavelength(A)Fig. 1. Neon spectrum taken at 10 MeV.

70

The resolution is however not high enough to identify the individual lines of 2p3p-2p3d transition. In
Table 1, the tentative assignment is listed. FUrther
study is now in progress with emphasis on the higher
resolution.
Table 1. Tentative assignment of observed lines.
Wavelength Transition
(nm)
n=8-9
567
7-8
529
9-10
480
10-12
466
9-11
456
11-14
450
8-9
434
7i-8k
389
7h-8i
386
377
2p3p-2p3d
I
367
8-10
331

Ion(Sequence)
VII
VI
IX
VIII
VII
VIII
VIII
VII
VII

(Be)
(B)
(He)
(Li)
(Be)
(Li)
(Li)
(Be)
(Be)

VII

(Be)

VII

(Be)

References
1) K. Bockasten, R. Hallin, and T. P. Hughes: Proc. Phys.
Soc., 81, 522 (1963).
2) B. C. Fawcett and F. E. Irons: ibid., 89, 1063 (1966).
3) G. Tondello and T. M. Paget: J. Phys., B3, 1757 (1970).
4) H. Hermansdorfer: J. Opt. Soc. Am., 62, 1149 (1972).
5) L. Barretle, D. J. G. Irwin, and R. Drouin: Physica
Scripta, 12, 113 (1975).
6) R. Hallin, J. Lindskog, A. Marelius, J. Pihl, and R.
Sjodin: ibid., 8, 209 (1973).
7) B. Denne, L. Engstrom, S. Huldt, J. O. Ekberg, L. J.
Curtis, K. Ishii, E. Veje, and I. Martinson: ibid., 21,
151 (1980).
8) L. Engstrom: ibid., 29, 113 (1984); ibid., 31, 379 (1985).

RIKEN Accel. Prog. Rep. 28 (1995)

Binary Encounter Electron Peaks for 0° Electronsin Collisions of Biq +Y. Kanai, T. Kambara, M. Oura, Y. Nakai, T. M. Kojima, S. Kravis, and Y. Awaya
Previously, we studied the binary encounter electron(BEe) peaks in collisions of Bi q + on H 2, He, and Ar at
0° electron emission angle with varying incident charge
states (q) and incident energies. 1- 3 ) The BEe has been
known as the electron emitted from the target essentially by the binary encounter collisions between the
projectile ions and the target electron in the high energy ion-atom collisions. Recently, the shift ~Eb in thepeak energy from the value for pure binary collisions
and the double differential cross sections of the BEehave been measured by many other groups to study
the production mechanism of the BEe, and comparedwith the theoretical works quantitatively.4) Theoretical
calculations can explain the q dependence of the double
differential cross sections of the BEe in the simple collision system (bare and H-like ions on H 2 , He). However,
it is rather difficult to calculate them for complex collision systems involving the projectile ions with manyelectrons . We have measured the q dependence of the
double differential cross sections of the BEe in the collisions of Bi q + with H 2, He, and Ar, and compared itwith that for simple collision systems to get the information of the production mechanism of the BEe. We
have also measured the q dependence of the BEe peakshift in the same collision systems in a wide range ofq(10 :::; q :::; 34). From the previous experiments, 1-3)
we can say, qualitatively, that the features of the BEepeaks in the Bi q + collisions are as follows: (1) The
peak intensity depends on the incident charge, (2) the
peak shift depends on the incident charge, and (3) the
peak width depends on the Compton profile of the target electrons. These features are almost the same as
those of the BEe peaks in the simple collision systems.
The presence of many orbital electrons of the projectile ions does not seem to affect the main features of
the BEe peaks.
In this report, we present the q dependence of theBEe peak shift for 0.8 MeV jnucleon Bi q + on H2 and He
collisions and compare it with a simple model, quantitatively.
The beams of Bi q + from the RILAC were magnetically analyzed, collimated by two sets of four-jaw slits
system and focused on the target gas cell. Single collision conditions have been verified experimentally.
Figure 1 shows the q dependence of the BEe peakshifts ~Eb, i.e. , the difference between 4Epmj M andthe observed peak energy, where Ep is the projectile energy, m the electron mass, and M the projectile mass.
Here, we compare our results with the peak shift given
by a simple model (the adiabatic tunneling model).5)
In this model, there is a characteristic distance R c ,called the tunneling distance. When the projectile ion
comes to this distance from the target, the target elec-

Binary Peak Shift at 0°
0.8 MeV/amu Bi q+ + He

Binary Peak Shift at 0°
0.8 MeV/amu BW + H2

>400
OJ

~400

rJ)

OJ
:::J

til

>

.t=

65 200
-'"
<1l
OJ

Cl..

( a)

o

10

20

30

40

( b)

50

Incident Charge State ( q )

o

10

20

30

40

50

Incident Charge State ( q )Fig. 1. Binary encounter peak shift in the collisions between 0.8 MeV/nucleon Biq+(q = 10-34) and H2, He.
Circles: observed values. Solid line: adiabatic tunnelingmodel. (a) Bi q + - H2 system, (b) Bi q + - He system.

trons tunnel to a projectile continuum state. After
that, the tunneled electrons collide with the projectile
ion as free electrons having effective collision velocity
Vel I = (4v 2 - ~Eb) 1/2. This model gives the energy
shifts ~Eb and Rc as follows:~Eb =It + -qi + v 2 - v
Rc.

2J1 - - - - - (a. u.) (1)2It
v2(a.u.).

2qi
Rc V2

(2)

Here, It is the ionization potential of the target, Z2
the target (effective) atomic number, and v the collision velocity. Our results are shown in Fig. 1. The
calculated peak shift values are also shown in Fig. 1
as the solid line. Our results are in good agreementwith the prediction of the adiabatic tunneling model.
In order to get the q dependence of the double differential cross section of the BEe in this model, we needto calculate the double differential cross section of thebinary encounter collisions between the free electron
having Vel I and the Bi ions.
By using heavy projectile ions with many electrons,
we could observe clearly the incident charge state dependence of the BEe peak energy.
References
1) Y. Kanai et al.: Proc. 6th Int. Conf. on the Physics
of Highly-Charged Ions (Manhattan, Kansas, 1992),
edited by P. Richard, M. Stockli, and C. D. Lin, AlP,
New York, p. 315 (1993).
2) Y. Kanai et al.: RIKEN Accel. Prog. Rep., 26, 65(1992).
3) Y. Kanai et al.: ibid., 27, 64 (1993).
4) M. Sataka et al.: J. Phys., B27, LI71 (1994).
5) P. D. Fainstein et al.: Phys. Rev., A45, 6417 (1992).

71

RIKEN Accel. Prog. Rep. 28 (1995)

Binary Encounter Electron Production at
Relativistic Collision Velocities
B. D. DePaola, Y. Kanai, P. Richard, Y. Awaya, T. Kambara, and Y. Nakai
Recently, there has been much interest in binary encounter electrons (BEe). These are electrons which areejected from a target, generally in gas or vapor phase,
following a "binary" collision with a fast projectile.
That is, in a classical model, these are electrons whichsuffer an impulsive billiard-balI-like collision and areejected with some distribution centered about a velocity which is (non-relativistically) twice that of theincoming projectile. The distribution in this simple
model is just the initial momentum distribution of thetarget electron, projected onto the collision axis, i.e.
the Compton profile. In this simple model, the crosssection for BEe production is given by the Rutherford
scattering formula.
This model, with some refinements, has been remarkably accurate in predicting BEe peak locations,shapes, and absolute, differential (in angle) cross sections. All experimental tests , of this simple impulse
model have been done at non-relativistic projectile energies. In the experiments described here, a highly
charged ion beam was used to investigate BEe production, differential in angle, and at relativistic velocities,
using solid targets. Thus, the experiments discussed
here differ from those done previously in several significant ways. Specifically, it was desired to measure
relative cross sections for BEe production as a function of electron emission angle. Also, it was desired tomeasure the shape of the BEe emission peak (within
the resolution of the electron spectrometer) and thelocation of the BEe peak.
The apparatus used in these experiments consistsof an ultra-high vacuum chamber, a remote-controlled
foil positioner, and an electron spectrometer, whose
entrance angle with respect to the projectile axis
was remote-controlled.
The projectile beam, 93
MeV /nucleon Ar q + (q = 17,18) was passed througha thin carbon foil, followed by the electron spectrometer, and finally into a Faraday cup. Foils of various
thickness, from 22 to 83 J,Lg/ cm 2 , were used with noapparent difference observed in either the BEe peakwidth or position.
The electron spectrometer has been used at RIKEN
in the past. It consists of a simple solenoid attached to
specially shaped pole pieces. The electrons are made topass between the pole pieces and are deflected throughan angle related to their momenta before being detected in an electron multiplier (EM). The spectrometer has a momentum resolution of 3%. The spectrometer is scanned using an NEC pc-controlled power supply which sources a current through the solenoid. In
scanning the spectrometer, counts from the EM are ac72

cumulated for a time proportional to the accumulated
charge in the Faraday cup.
In Fig. 1 two typical electron spectra are shown.
These are plots of accumulated electron counts versus
spectrometer current (in Amperes). The spectra weretaken at 0°, or along the projectile axis. The curve
composed of circles is for Ar 17+ projectiles, while thecurve composed of triangles is for Ar 18+ projectiles.
In the Ar 17+ curve the sharp structure at about 0.25
Amps is the so-called cusp peak, corresponding to electrons captured or lost to the continuum of the projectile. At these velocities the cusp is almost entirely due
to electron loss to the continuum, as evidenced by the

105

0
0

10'

93 MeV/u Arq + + C foil

0

"'",

0=0"

'"

00'"
0

00'"

0

0'"

en

103

'E
::l
0

0

102

OV'y

°

0 ",

0

0

q=1 7

"

q=18

"'6

0

08~

0

'"'"

0
00

'"v
10 '

0.2

13

0

'V'VQQ"QV

100
0,1

0

'Q

OOdOC~:P()Oo~\]'V TVV' v'QV''Q'Vt)'V'V~

0.3

"',7

v,\if

\'

0

"

-I,

°oz.r

(J~(3~)~~\.

0.4

0.6

0.5

Fig. 1. Typical electron momentum spectra at 00. The
projectile is 93 MeV/nucleon Arq+. The circles are datafor q = 17, while the triangles are for q = 18.

93 MeV/u Arq + + C foil

30

40

50

60

Lab frame scattering angle

Fig. 2. The momentum of the peak of the binary encounter structure as a function of laboratory frame electron emission angle. The projectile is 93 MeV/nucleon
Arq+. The circles are data for q = 17, while the triangles are for q = 18. The calculation is from a simple
relativistic "billiard-ball" model.

almost complete lack of a cusp in the Ar 18+ data. Bothcurves show a structure at about 0.5 Amps. This is theso-called binary encounter electron peak, and was thefocus of attention in this series of experiments.
In order to study the properties of the BEe peak as afunction of emission angle, a series of spectra like thoseshown in Fig. 1 were taken over a range of emission angles from 0° to 60° (lab frame). Figure 2 shows a plotof the momentum of the peak of the BEe structure as afunction of electron emission angle. Also shown in Fig.
2 as a solid line is the predicted location of the momentum of a free electron after suffering a billiard-balI-likecollision with a 93 MeV/nucleon Ar projectile. The
agreement is striking, indicating that the simple rel-ativistic impulsive model· is an accurate predictor of
the final momentum of the scattered electron.
Analysis is currently underway to determine if thecross sections, differential in angle, are adequately described by Rutherford scattering, as is the case forlower velocity collision systems. It will also be interesting to see if the cross sections scale with projectile
charge in the same way as in the lower velocity regime.
It is well known that at lower velocities screening andinterference effects are important in the BEe production cross sections. No relativistic theory for BEe currently exists, but it is thought that screening and interference effects should not be important at the velocities
investigated here.

73

RI KEN Accel. Prog. Rep. 28 (1995)

Charge Distribution of Kr Ion Passing throughThin Carbon Foil at 36 MeV/nucleon
Y. Nakai, T. Kambara, Y. Kanai, T. M. Kojima, and Y. Awaya
We have measured the charge state distribution of
Kr ion passing through a thin C foil for radiative electron capture (REC) X-ray experiments using Kr 36 + at
36 MeV/nucleon from RIKEN Ring Cyclotron. The
charge state of Kr ion passing through the C foil was
analyzed by the dipole magnet on the downstream of
the C foil. A 2-dimensional position sensitive gas detector was located at the exit of the dipole magnet andused to count the Kr ions. The gas detector has a 1 mm
spacing stripe electrode and a 2 mm spacing wire electrode for determination of horizontal and vertical position respectively, and has a cathode plane of conductive polymer foil. All the strips and wires on each electrode were connected each other with resistors. The
position detection was accomplished by a charge division method. Its active area was 170 mm x 80 mm.
The horizontal position spectrum is shown in Fig. 1.

The C foils of 10 J.Lg/cm 2 and 20 J.Lg/cm 2 were used.
Moreover, the effective thickness along the beam axis
was changed by tilting the 20 J.Lg/cm 2 foil at 35°.
The number ratios between Kr 36 + and Kr 35 + andbetween Kr 35 + and Kr 34 + were measured. In the
Kr 35 + _Kr 34 + case, the fitting procedure was used for
reduction of the yield of two charge states. The fraction of charge states less than 34+ was so small and weassumed the total number of incident particles was thesum of the numbers of Kr 34 +, Kr 35 +, and Kr 36+. The
errors is only derived from the statistical one and thefitting procedure. The uncertainties of C-foil thickness
and the absolute tilted angle are not exactly estimatedyet. The fraction of charge state from 34+ to 36+ isshown in Fig. 2.

36+

.3

ro
+'

10°

8

8

8

(fJ

~1O-1

104

I-.

ro

..c:
~ 10- 2o35+oL--------+---+•

1=1:3 10- 3
()

ro

I-.

34+

~ 10- 4o

10 1ChannelFig. 1. The horizontal position spectrum.
Kr 35 + peaks are shown.

74

x. ·

Kr 36 + and

5

10
15
20
Thickness (p.g/cm 2 )

·· x

25

30

Fig. 2. The fraction of each charge state. The verticalerror bars are smaller than symbol size. Two values
at the thickness 10 J-Lg/cm 2 are corresponding to thedifferent runs. The uncertainties of foil thickness andabsolute tilted angle of foils are not included in thisfigure.

RIKEN Accel. Prog. Rep. 28 (1995)

Momentum Distribution of Recoil Ions from 8. 7 MeV
0 7+-He Collisions
T. Kambara, Y. Awaya, Y. Kanai, Y. Nakai, T. M. Kojima, O. Jagutzki, and H. Schmidt-Bocking
We have measured the three-dimensional momentum distributions of the recoil ions from collisions between 8.7 MeV 0 7 + ions and a target of He atoms incases of pure ionization 0 7 + + He ~ 0 7 + + He + andone-electron capture 0 7 + + He ~ 0 6 + + He+,2+ tostudy the dynamical processes between highly-charged
heavy ions and few-electron atoms.
The longitudinal (parallel to the projectile) component of the recoil ion momentum from an ion-atomcollision with velocity vp is expressed as:p

PIIR = -Q/vp - n ev p/2 - LPIlei(1)

ions for pure single ionization 0 7 + + He ~ 0 7+ + He +are shown in Fig. 1. Figure l(a) shows the Pl.. distribution in the horizontal component obtained fromthe TOF measurement and (b) the vertical component
from the detection position on the recoil ion detector.
The centroid of the vertical distribution shifts upward
by about 1.6 au due to mass motion of the target He
atom in the jet with velocity of 450 m/s. The FWHM
of the distribution is about 1 au for both the components. The momentum distribution of He 2 + is wider
than that of He+, but the yield of He 2+ was too small
to determine the momentum distribution.

i=lwhere Q is the Q value, ne is the number of the transferred electrons in the process, and Pile is the longitudinal momentum of the ionized electrons. Therefore thiscomponent reflects the transfer of electrons and changeof the total kinetic energy of the ions. The transverse
components are expressed as:

400 (a) Horizontal Component Px(TOF)
200
(J)

p

Pl..R = -Pl..P - LP.l..ei

(2)

i=l

and reflect the momentum transfer due to the projectile scattering and emitted electrons'!)
In the experiments, an 0 3 + beam from RILAC
passed a carbon foil to strip the electrons and thehydrogen-like 0 7 + ions were selected. Then the momentum of the ions was analyzed by a bending magnet. The energy of the ions was about 8. 7 MeV whichcorresponds to the velocity of 4.7 atomic unit (au) andmomentum of 1.4 x 105 au. It was estimated that about
99.8% of the metastable ions decay before the target.
The ion beam was collimated by a pair of slits and was
led to a target chamber where it crossed a target of Hegas. The target was a cooled gas jet which crosses theion beam at about 90°. The momenta of the He+ andHe 2 + ions were analyzed by an electrostatic recoil-ion
analyzer. The recoil ion analyzer with the gas jet target and an electrostatic recoil ion spectrometer are described elsewhere in this report. 2 ) After the target, theoxygen ions in a charge state of 6+ or 7+ were selectedby a dipole magnet and were counted by a parallelplate avalanche counter (PPAC) with two-dimensional
position sensitivity in coincidence with the three dimensional momentum of the recoil ions.
The transverse momentum Pl.. distributions of He+

C
::l
o

U

400 (b) Vertical Component py(MCP)

200

...

..

o
2
Transverse Momentum (au)Fig. 1. Momentum distribution of recoil He + ions frompure ionization by 8.7 MeV 0 7 +: (a) is the horizontal
component obtained from the time of flight measurement and (b) is the vertical component obtained fromthe vertical position of the ions at the MCP of the recoil
ion analyzer. A curve in (a) shows the Compton profile of He atom experimentally obtained by Eisenberger.
The abscissa is the momentum in atomic unit.

References
1) R. Dorner, V. Mergel, R. Ali, U. Buck, C. L. Cocke, K.
Froschauer, O. Jagutzki, S. Lencinas, W. E. Meyerhof,
S. Niittgens, R. E. Olson, H. Schmidt-B6cking, L. Spielberger, K. Takesi, J. Ullrich, M. Unverzagt, and W. Wu:
Phys. Rev. Lett., 12, 3166 (1994).
2) O. Jagutzki, T. Kambara, Y. Nakai, Y. Awaya, and H.
Schmidt-Backing: This report, p. 129.

75

RIKEN Accel. Prog. Rep. 28 (1995)

Single Event Effect in Power MOSFETs
by High-Energy Heavy Ion
S. Matsuda, S. Kuboyama, T. Akutsu, T. Hada, J. Aoki, T. Hirose, H. Ohira, T . Kohno,
N. Inabe, T. Nakagawa, M. Kase, A. Goto, and Y. Yano
Power MOSFETs (Metal-Oxide-Semiconductor
Field Effect Transistors) perform excellently as powerswitching devices. However, power MOSFETs havea possible catastrophic failure mode known as Single
Event Burnout (SEB) phenomenon which is important
to consider in space electronic applications.
The detailed mechanism for SEB was observed experimentally by the EPICS (Energetic Particle Induced Charge Spectroscopy) measurement system inprevious work. 1) The experimental results were also
confirmed with numerical simulation technique.
To prove the effect of a nuclear reaction on SEBs,
SEBs were measured l?y EPICS with heavy ions whichhave the same LET but different energy. The selected ions were Kr and Xe and their characteristics
are shown in Table 1.

fact will be explained by the nuclear reaction which
deposits excess charges in the active layer of a semiconductor.
The effect of the nuclear reaction was experimentally
proved. 2) The results suggest that a usual SEB immunity test as a function of LET should be carefully
considered to simulate the actual space environment
for high voltage devices which have a thicker sensitive
layer.

~o.JPI_J. . .,~,l- pe_a_k_2: . :;S. :OV. ~!

I924MeV ...K_r_,__1s....

1/1

::3
0

Table 1. Characteristics of the ions used in this study.

(,)

EnergyLET
Range[MeV] [MeV /(mg/c~2)] [JLm(Si)]
924
3536

27.5
33.7

,

d

1 0- 1 1 0 0

76

~

lS0V

~

100V

U\

127
363

RIKEN Ring Cyclotron was used for the heavy ions
irradiation. To avoid contaminant ions, a defocused
direct beam without a scatterer such as Au foil wasused. The incident beam was monitored by an SSD
just adjacent to the sample device.
The sample device used in this study was 2SK725
manufactured by Fuji ElectriC Corp. The device has
a maximum drain-source voltage rating (VDs) of 500
V. The high voltage rating requires a relatively thickactive layer (~40 J.Lm of epi-Iayer). However, both ionshave sufficient ranges to penetrate throughout the active region of the sample device.
Figures 1 and 2 show the EPICS spectra for Kr and
Xe ions, respectively. At 50 V of V DS, the first peak isin the same position. This fact comes from that the Kr
and Xe ions have the same LET value. However, theobserved SEB thresholds for Kr and Xe ions were 250
V and 95 V, respectively. Obviously the threshold voltage is not solely determined by LET of incident ions.
For Kr ions, the V DS dependence of the EPICS spectra
is normal as compared with another typical case. In
previous work on Power MOSFETs, it was suggested
that SEB was triggered when a collected charge exceeded a certain threshold charge QTH. 1 ) In contrast
with the Kr ions, SEBs in Xe case are triggered although the second peak still remains below QTH. The

'SEB

J1

_ _~~\~____2~O..::...
OV
___

C
Ions

_

'

1 01

Signals

VOS= SOV

d

'

d

•

1 05

1 06

!

1 02 1 03 1 04
Charge [pC]

Fig. 1. EPICS spectra for 924 MeV Kr ions.

.2nd peak13536Mev Xe

I
210V

200V
1/1

'E::3
,

150V

o

(,)

100V

'SEB
_ _ _ _ .....,,

d

1 0- 1

1 00

J'-_--:;.;;;..~-'--_!

I

1 01 1 02 1 0 3
Charge [pC]___=signals

J

J

•

1 04

1 05

1 06

Fig. 2. EPICS spectra for 3536 MeV Xe ions.

References
1) S. Kuboyama et al.: IEEE Trans. Nucl. Sci., NS-39,
1698 (1992).
2) S. Kuboyama: ibid. , NS-41, 2210 (1994).

RIKEN Accel. Prog. Rep. 28 (1995)

Laser Spectroscopy of Atoms in Superfluid Helium
M. Nakamura, Q. Hui, J. L. Persson, and M. Takami
Neutral atoms in superfluid helium (Hell) are known
to be trapped in bubble-like cavities formed by a strong
repulsive force between the atoms and surrounding helium atoms. The excitation and emission spectra ofsuch bubble atoms exhibit peculiar spectra due to thecoupling of atomic electronic states with the vibrational motion of the bubble. Almost all the bubble
spectra have a very broad and largely blue-shifted excitation (absorption) band and emission lines close to
free atomic lines with a typical width of 1-2 nm. l )On the other hand, magnetic resonance and hyperfine
transitions in the ground electronic states are known
to have widths and resonance frequencies very close
to those in free space. 2 ) One of the objectives of thepresent work is to develop an experimental techniqueto study the fine structure and magnetic moments ofatoms with unstable nuclei in Hell.
We are currently studying optical properties of neutral atoms in Hell with lasers. A schematic diagramof the experimental set up is shown in Fig. 1. Neutral
atoms are dispersed in Hell by laser ablation of solid
metal samples immersed in Hell. 3 ,4) A pulsed YAG
laser beam (355 or 532 nm, ",30 mJ / pulse) ablated
the metal sample and produced a large number of small
particles of the sample material. A second YAG laser
Dissociation
laser
Focusing
lens

Probe
laser

beam (355 or 266 nm wavelength, ",10 mJ/pulse) witha few ms delay after ablation dissociated the particles
to disperse neutral atoms in Hell. A pulsed dye laser
was used to excite the atoms with a 50 ns-l0 ms delay
time after dissociation. The emission from the bubble
atoms was detected by a photomultiplier through a 25
cm monochromator.
So far we observed bubble spectra for a number ofneutral atoms. A part of the experimental data including the group IlIa atoms are listed in Table 1. For
the dynamics of bubble atoms, we measured radiative
lifetimes for a number of atoms and found that mostneutral bubble atoms have radiative lifetimes close to
those in free space, but atoms in highly excited states
or in an unidentified free-atom-like state show complex
behavior. 5 ) The efficient quenching of the excited state
by resonant radiation observed in Yb confirmed therapid relaxation of bubble modes. 6 ) We also succeededin the observation of highly excited states in Ca andSr where the Coulomb potential is severely distortedby the existence of a bubble.
Table 1. New bubble transitions.
Atom
Yb
Ag
Al
Ga
In

Excitation a ) Emission Free space
(nm)
(nm)
(nm)
7s 3S 1--6p 3P2
769.9
670
770
338.3
320
338
5p 2Pl/2- 5s 2S 1/2
394.4
4s 2S1/2-3p 2P 1/ 2
358
394
403.3
5s 2Pl/2-4p 2P 1/ 2403
368
6s 2P 1/ 2-5p 2P 1 / 2
410
410.2
364
Transitiona) Center of broad absorption band.

Hell

Glass

dewar

Fig. 1. Experimental set up.

References
1) H. Bauer et al.: Phys. Lett., A146, 134 (1990).
2) T. Yabuzaki: private communication.
3) A. Fujisaki et al.: Phys. Rev. Lett., 71, 1039 (1993).
4) J. H. M. Beijersbergen et al.: Phys. Lett., A1B1, 393(1993).
5) Q. Hui et al.: Z. Phys., B, in press.
6) Q. Hui et al.: Laser Chemistry, 15, 221 (1995).

77

RIKEN Accel. Prog. Rep. 28 (1995)

Muonium Centers in Crystalline Si and Ge under Illumination
R. Kadono, A. Matsushita, R. M. Macra~, K. Nishiyama,* and K. Nagamine
An isolated hydrogen atom is the simplest interstitial impurity in crystalline semiconductors and therefore serves as a testing field for the basic understanding of atomic defects in these materials. Moreover, therecent revelation that atomic hydrogen can form chemical complexes with shallow impurities and thereby
passivate their electrical activity (i.e., hydrogen passivation) , of crucial importance in the processing ofsemiconductor devices, has prompted wider interest in
the structure and kinetics of hydrogen isotopes andtheir complexes with other defect impurities. U nfortunately, compared with hydrogen complexes relatively
little is known about isolated hydrogen in semiconductors. This is in marked contrast to the case of muonium (Mu, a bound state of J.L+ and e-) where it is
widely investigated as an isolated center. Thus, thestudy of Mu centers serves as a complementary sourceof information on hydrogen isotopes in semiconductors. However, a standing issue of Mu study is that a
considerable fraction of muons implanted into intrinsic
Si/Ge at low temperatures are found as Mu~ centers,i.e., those at the tetrahedral interstitial (T) site, whilemost calculations predict the bond-center (BC) site tobe the adiabatic potential minimum for neutral muonium and hydrogen. 1)
In order to get an insight into this problem we conducted a time-differential J.LSR experiment upon Si
and Ge under illumination. A xenon fiashlamp (0.5mJ/cm 2 per pulse, synchronized with the muon pulse)
was used to illuminate the specimen with minimal heatload and conventional J.LSR measurements were performed under longitudinal field (LF) or transverse field(TF) conditions. The electronic state of the muon isdetermined through the magnetic field dependence ofthe (time dependent) positron decay asymmetry,

A(t) = Ao[f± + fTPT(t, B) + fBCPBC(t, B)],(1)

where Ao is the experimental asymmetry, fa is therelative yield of the charged state (Mu±), Mu~ , andMu~c centers (a = ±, T, BC, satisfying La fa = 1),
and Po.(t, B) is the corresponding polarization function dependent on the time t and external field B.
The muon depolarization due to cyclic charge exchange(e.g., Mu±~Mu~), which turns out to be the predominant process under illumination, is qualitatively
the same as that due to spin exchange interactions
involving the relevant neutral state (e.g., Mu~) andthe characteristics of the regime may thus be stud-

Meson Science Laboratory, Faculty of Science, University of
Tokyo

78

ied through the behavior of the neutral intermediate
state. 2 )We found that the charged state (Mu±) formed athigh temperatures undergoes fast spin relaxation inboth Si and Ge under illumination due to a cyclic
charge exchange reaction with photo-induced carriers.
In Si the Mu~ state also collides effectively with carriers to induce reaction, while in Ge the neutral state isunreactive. In particular, in Si at low temperatures theMu~ center is rapidly converted into Mu~c with supervening fast spin relaxation under illumination. As
shown in Fig. 1, the initial LF-J.LSR asymmetry at 8
K is reduced by illumination, indicating that Mu~ hasbeen transformed into Mu~c (fBC = 0.5 -+ 1), and evidencing that the Mu~c state is the true ground state at
low temperatures. The details are found elsewhere.3)

.2

>0:::

.1 5

f--

~ .1
:2

>Vl

«

.1

Si (110)
0"[

!

,

!

J

o .0 5 .1 .15 .2 .25 .3 .3 5 .4
FIELD (T)Fig. 1. Longitudinal field dependence of the initial asymmetry A(t = 0) in illuminated Si at 8 and 298 K. Solid
curves at 298 K are fits to Eq. (1). At 8 K the dashedcurve is calculated with jBC = 1 and the solid curvewith further depolarization at the initial Mu~ state.

References
1) See, for example, the review by C. G. Van de Walle,
Hydrogen in Semiconductors, p. 585 (1991).
2) I. G. Ivanter and V. P. Smilga: Zh. Eksp. Teor. Fiz.,
60, 1985 (1971) [Sov. Phys. JETP, 33, 1070 (1971)].
3) R. Kadono, A. Matsushita, R. M. Macrae, K.
Nishiyama, and K. Nagamine: Phys. Rev. Lett., 73,2724 (1994).

RIKEN Accel. Prog. Rep. 28 (1995)

Annealing Behaviour of Kr Atoms in Kr-Implanted Aluminium
E. Yagi and M. Hacke
It has been demonstrated that heavy inert gas atoms(Ar, Kr, and Xe) implanted into metals at ambient temperature precipitate into micro-clusters, andthat for high implantation doses they are in a solid
phase (solid inert gas bubbles) epitaxially aligned tomatrices. 1-3)
From previous channelling studies on Kr-implanted
Al crystals, we obtained the following results. At theinitial stage of implantation various types of complexes
consisting of Kr atoms and vacancies (V) such as KrV4 'KrVt; and larger ones are formed, and act as nucleation
centres for the subsequent bubble formation. 4- 6 ) The
complexes KrV4 and KrV6 are stable up to about 400
K and 560 K, respectively. The formation of epitaxial
solid krypton is enhanced by post-implantation irradiation at room temperature. 7) The solid krypton is also
formed on annealing. 6)
The result described above on the stability of thecomplexes was obtained from isochronal annealing experiments of a 1 x 1015 Kr/cm 2 implanted specimen.
However, it is desirable to demonstrate the stabilityof the Kr V4 more clearly, because the fraction of the
KrV4 complexes was small in the 1 x 10 15 Kr/cm 2 implanted specimen, and the change in its fraction on
annealing was small. Therefore, in the present study
its stability is investigated by a channelling method2
in a 4 x 10 14 Kr/cm implanted specimen which contains a larger portion of KrV4 complexes than in the2
1 x 1015 Kr/cm implanted specimen.
Kr+ implantation was carried out at room temperature at 50 keV with a dose of 4 x 1014Kr/cm2. Channelling analyses were performed at room temperature
with a 1.0 MeV He+ beam in the as-implanted state
and aft.e r annealing at 433 K for 30 min.
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 the(100) and (111) channels, and a central peak superimposed on a shallow dip for the (110) channel. In the(100) Kr profile a small central peak is superimposedon the dip as shown in Fig. l(a). The relative depth ofthe (100) Kr dip with respect to the corresponding Al
dip is smaller than that of the (111) Kr dip. As previously reported,4-7) these profiles can be interpreted as
showing that the Kr atoms are distributed over substitutional (8), tetrahedral (T), octahedral (0), andrandom (R) sites. The observed small (100) central
peak originates from the T-site occupancy, and the(110) central peak from the T- and O-site occupancies. As the fraction of the O-site occupancy is muchlarger than that of the T -site occupancy, the contribution of the O-site occupancy to the (110) central peak

(a)

(b)

<100>

o Al

• Kr

g 1.0

w

;>:

o

W

N

::::J

<!

:2: 0.50:::oZo~~~~~~~~~~~~~~~

-2

0

2

-2

a

ANGLE(deg)Fig. 1. (100) channelling angular profiles obtained forthe 4 x 1014Kr/cm2 implanted specimen (a) in the
as-implanted state, and (b) after annealing at 433 K
for 30 min. The broken curves are Kr angular profiles
calculated for the distribution ofKr atoms with (a) 20%
at S, 6% at T, 19% at 0 and 55% at R sites, and (b)20% at S, 19% at 0 and 61% at R sites. The solid
curves were drawn only to guide the eye.

is much larger than that of the T -site occupancy.
After annealing at 433 K, the small (100) central
peak disappears (Fig. l(b)), and the relative depthsof the (100) and (111) Kr dips become equal. The(110) central peak is still observed. The T-site occupancy has been interpreted to be a result of the interaction between Kr atoms and implantation-introduced
vacancies: By trapping 4 vacancies a Kr atom is located at the centre (a T site) of a vacancy tetrahedron.
Therefore, the result described above can be explainedin terms of the dissociation of KrV4 complexes, anddemonstrates that the Kr V4 is stable up to about 400
K. More detailed descriptions are given in Ref. 8.
References
1) A. vom Felde, J. Fink, Th. Miiller-Heinzerling, J.
Pfluger, B. Scheerer, G. Linker, and D. Kaletta: Phys.
Rev. Lett., 53, 922 (1984).
2) C. Templier, C. Jaouen, J.-P. Riviere, J. Delafond, andJ. Grilhe: C. R. Acad. Sci. Paris, 299, Ser. II, 613(1984) .
3) J. H. Evans and D. J. Mazey: J. Phys. , F15, L1 (1985).
4) E. Yagi: Phys. Stat. Sol., a104, K13 (1987) .
5) E. Yagi: Nucl. Instrum. Methods Phys. Res., B39, 68(1989).
6) E. Yagi, I. Hashimoto, and H. Yamaguchi: J. Nucl.
Mater. , 169, 158 (1989).
7) E. Yagi: Phys. Rev. Lett., 67, 3804 (1991).
8) M. Hacke and E. Yagi: J. Phys. Soc. Jpn., 64(3), (1995),
in press.

79

RIKEN Accel. Prog. Rep. 28 (1995)

Hyperfine Magnetic Field of 61 Ni in Spinel Chromite
CUo.9Nio.1 Cr204
T. Okada, Y. Noro,* Y. Kobayashi, H. Kitazawa, and F. Ambe
About twenty years ago, we reported that in the
61 Ni Mossbauer spectroscopy a large hyperfine magnetic field (H hf ) of 450 kOe for 61 Ni was found at the
tetrahedral (A) sites of NiCr204 with a spinel structure in contrast with the smaller Hhf around 100 kOe
at the octahedral (B) sites of NiFe204 etc. 1) After that,several groups reported 61 Ni Mossbauer measurementsof spinel oxides. In early times, the interaction of themagnetic moment of the nucleus with the electron spinand orbital moment was studied by E. Fermi and E.
Segre. 2) It is deduced from this interaction that Hhf
consists of three parts of Fermi contact , the orbital angular momentum and the magnetic dipole-dipole interaction. When the electron in the ground state has anangular momentum, the second part gives very large
Hhf. Goring pOinted out firstly that the large Hhfof 61 Ni at A sites of NiCr204 arose from the incompletely quenched orbital angular momentum3 ) by thesecond order perturbation though the orbital angularmomentum was quenched by the first order one. As
any compounds except for NiCr204 and NiCr2-xFex04
have not been investigated, the Hhf of 61 Ni in various compounds has to be measured in order to elucidate the origin of these large Hhf. The specimen of
CUO.g61 Nio.l Cr204 has a spinel structure tetragonally
distorted (cia = 0.92) due to the Jahn-Teller effect of
Cu2+ ions at the tetrahedral sites where the groundstate of Ni ions is doubly degenerated and then theorbital angular momentum is still wholly alive. This
paper purposes to measure the Hhf of 61 Ni ions in the
doubly degenerated ground state.
The single line source of 61Cu (-+ 61 Ni) was produced in the RIKEN AVF cyclotron. A powdered specimen of CUO.g61 Nio.l Cr204 was prepared by the conventional ceramic sintering method. The source andHitachi Image and Media System Laboratory

80

absorber were kept at the same temperature in a helium cryostat.
A Mossbauer spectrum of CuO.g61 Nio.l Cr 204 taken
at the liquid He temperature is give in Fig. 1. One cansee the widely spread lines. The value of the internal
magnetic field Hhf amounts to 830 kOe, which is thelargest one ever reported for 61 Ni. In conclusion, we
found the large Hhf of 61 Ni ions in the doubly degenerated ground state. It is considered that the large Hhfof 61 Ni at A sites of spinel oxides is caused by the orbital angular momentum because it is still wholly alivein the doubly degenerated ground state.

~c 100 '., •.-;o..... : ..

'iii
en

'E

en
c

,g 99
Q)

>

.~

4K

Qj

a::
-20

-10

0
10
Velocity (mm/s)

20

Fig. 1. 61 Ni Mossbauer spectrum of spinel chromite
Cuo.g61Nio.1Cr204 at 4 K. The solid line is the guide ofeyes.

References
1) H. Sekizawa, T. Okada, S. Okamoto, and F. Ambe: J.
de Physique, 32, C1-326 (1971).
2) E. Fermi and E. Segre: Z. Physik, 82, 729 (1933).
3) J. Goring: Z. Naturforsh., A26, 1929 (1971).

RIKEN Accel. Prog. Rep. 28 (1995)

T. Okada, Y. Kobayashi, T. Tatsumi,* and N. Yamada*
The Sr compound YSr2CU307-y has a similar crystalline structure with a typical high-T c superconductor
YBa2CU307-y and is also superconductive. The elucidation of the resemble and different features between
both compounds is attractive and significant to investigate the origin of a high-T c superconductivity. The Bacompounds YBa2Cu3-xFex07-y, substituting Fe for Cu
atoms in YBa2CU307-y, have been studied by many researchers. The Sr compounds YSr2Cu3-xFex07-y havebeen studied also and found that the solubility rangeof Fe atoms is 0.3 ~ x ~ 1.0 when the Sr compounds
are calcined in flowing O 2 gas.
Our attention is as follows:(1) In spite of the similarity of the superconducting transition temperature between these compoundswith Fe content x = 0.3, the Mossbauer spectra ofthese compounds are different. It is expected that thedifference of a microstructure in these compounds can
be clarified by the analysis of the Mossbauer data.
(2) For the highly Fe substituted compounds, e.g.
YSr2Cu2Fel07-y (x = 1), new magnetic ordering states
are expected. We studied the magnetic states in thecompound by means of the magnetization and theMossbauer measurements.
The typical Mossbauer spectra of the powder specimen YSr2Cu2.7Feo.307-y in a temperature range from
4 K to 296 K are shown in Fig. 1. The spectra at 296 K
can be analyzed with three doublets arising from thequadrupole splitting (QS). The sites occupied by Feions can be classified into three sites. The isomer shifts(IS) of two sites are nearly zero and the IS of the othersite is +0.27 mm/s. The IS of the former are near thevalue for Fe 3+ ions in highly covalent oxides (Cu( 1)site). The IS of the latter is the ordinary value for
Fe 3+ ions in oxides (Cu(2) site). The area ratio of thethree sites in Mossbauer spectrum differs remarkably
from that of the Ba compounds YBa2Cu2.7Feo.307-y'
It means that the number of Fe 3+ ions occupied inCU(l) sites increases in the Sr compound. As shownin Fig. l(e), the spectrum at 4 K can be explained by asuperposition of two magnetically split sextets. In the
sharp sextet (A) the value of the hyperfine magnetic
field (H hf ) is around 450 kOe, and the values of Hhf

r

100t----~

'"\

(a)

296 K

.- 90r
~

~1 00

c

o

'00
.~

t---.. . -... .. 'r
\~.

(b)

!

J....

20K

!

: ;\ :

90

.:\:'

E 100

.' .'

~

~ ~
,~ I
15 K

(c)

~ 95

i 100 ~ \;,,-/ r--~

\ V

Q5 95

\

a: 100 ....

I

11 K

:

r--

\ (J

V

V\.

(e),

I
~

\

".,r
v

~V:
•
• to. •:\.J
.,.-

95

::V

(B),
(A) ,-I_

-10

«

1

1 1

4K

I

-,I ----L,---1,_-'-'---11o+10
Velocity (mm/s)

Fig. 1. Mossbauer spectra of YSr2Cu2.7Feo.307-y at various temperatures.

in the very broaden sextet (B) are widely distributed
around 200 kOe. The magnitudes of Hhf in the B sextet are smaller than that in the Ba compound. Furthermore, the values of Hhf in B sextet decrease more
rapidly with increasing temperature than that in the
Ba compound.
In summary, (1) the number of Fe 3+ ions occupied in CU(l) sites increases in the Sr compoundYSr2Cu2.7Feo.307-y, and the magnetic interaction ofthese ions is weaker than that in the Ba compound
YBa2Cu2.7Feo.307-y, and (2) though figures are notshown here, the temperature dependence of Hhf andthat of the magnetization in the highly Fe substituted
compounds are similar to those in the spin glass.

Department of Applied Physics and Chemistry, The University of Electro-Communications813. Radiochemistry and Nuclear Chemistry

RIKEN Accel. Prog. Rep. 28 (1995)

Multitracer Study on Transport and Distribution ofMetal Ions in Rice Plant
S. Ambe, Y. Ohkubo, Y. Kobayashi, M. Iwamoto, and H. Maeda
Although plants grow on soil containing various elements, little is known about uptake and accumulationof metal elements other than those regarded as essential ones. Human activities have led to the contamination of soil not only with heavy elements but alsowith radioactive isotopes. Elements artificially introduced to the environment can change the equilibriumin nature and their behavior in partition between soil
and water often differs from that of elements originallyexisting in soil, which would affect the uptake of elements by plants. Therefore, it is very important toinvestigate the uptake and distribution of metal ionsin plants and to evaluate the quantities of accumulation of stable elements and radioactive isotopes.
This paper reports on a study of the uptake anddistribution of various metal elements by means of themultitracer technique. Rice (Oryza sativa cv. Nihonbare) plant was hydroponically cultivated in a nutrient solution containing a multitracer prepared froma gold target.1,2) Distributions of various elements
among leaves, stems, and roots were determined by'Y-ray spectroscopy of each part of the plants.
The amount of radioisotopes taken up by each partof the plants is represented as percentage distribution
obtained by dividing the radioactivity in one part of aplant by the total amount of radioactivity added to theculture media. Figure 1 shows the percentage distribution of elements among various parts of the rice plant
which was transplanted 2 weeks after germination into
a nutrient solution containing a multitracer and grownfor 3 days. A large fraction of the radioisotopes of Sc,

Mn, Fe, Co, Zn, As, Rb, Sr, Y, Zr, Te, Ba, Ce, Eu,
Gd, Tb, Tm, Yb, Lu, Hf, Ir, and Pt was found in theroots and only a small fraction in the stems. Amongthem, the rare-earth elements showed relatively highdistribution in the roots. In the leaves, appreciable
amounts of Mn, Co, Zn, Rb, Sr, and Ba were detected.
The rice plant cultured in a nutrient solution containing the multitracer for 14 days showed an increasein the uptake of the elements by roots, stems, andleaves (Fig. 2). Essential elements Mn and Zn wereconcentrated in the leaves, showing an almost complete
uptake from the nutrient solution. Although Fe is also
an essential element, the amount of iron in the stems
and leaves was less than the detectable limit. This indicates that the plants have stored enough Fe during
the preceding culture stage. An increase in the amountof As, Rb, Sr, Te, and Ba in the stems and leaves wasobserved compared to the 3-day culture. The amountsof rare earth elements in the roots also increased withtime but they were not detected in the leaves. The
distribution of lanthanides in the roots was found to
decrease in the order of increasing atomic number.

100,.,..,----------1 0 Leaf2
mStem2

80

•

Root2

~ 60
~

!!
Q.

::) 4020o100 . - - - - - - - - - - - - - - , / 0 Lea"
filSt"""
80•

Element

Rool1

~ 60

Fig. 2. The percentage distribution of metal elements
among various parts of the rice plant grown in a nutrient
solution for 14 days.

j
!!
~ 40
20

References
Element

Fig. 1. The percentage distribution of metal elements
among various parts of the rice plant grown in a nutrient
solution for 3 days.

1) S. Ambe, S. Y. Chen, Y. Ohkubo, Y. Kobayashi, M.
Iwamoto, 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., 317 (1991).

83

RIKEN Accel. Prog. Rep. 28 (1995)

Multitracer Study on Transport and Distribution ofMetal Ions in Soybean Plant
S. Ambe, Y. Ohkubo, Y. Kobayashi, M. Iwamoto, and H. Maeda
Transport and distribution of metal ions in soybean
plants were studied using multitracers produced by irradiating an Au target by 135 MeV/nucleon 12C, 14N,
and 16 0 ions accelerated by RIKEN Ring Cyclotron.
The multitracer prepared from the target by solvent
extraction consisted of radioisotopes of the following
elements: Be, Na, Sc, Mn, Fe, Co, Zn, Se, Rb, Sr, Y,
Zr, Nb, Ag, Te, Ba, Ce, Pm, Eu, Cd, Tb, Tm, Yb, Lu,
Hf, Ir, and Pt.
Soybean plants (Glycine max L. Merrill cv.
Okuharawase) were grown in a nutrient solution containing a multi tracer. Distributions of various elements among seeds, leaves, stems, and roots were determined by ,-ray spectroscopy of each part of theplants. For comparison, soil cultivation was also performed.
Soybean plants 50 days after the start of germination were grown in a multitracer nutrient solution for
30 days. The results of analysis of the ,-ray spectra of
the roots, stems, leaves, pods, and seeds are shown in
Fig. 1. In the edible part, namely in seeds, Mn, Co, Zn,
Rb, Sr, and Ba were detected. The pods showed u~
take of the same elements as those in the seeds. Rb, Sr,and Ba were found to be distributed among all partsof the plant, similar to the distribution of the essential
elements Mn and Zn. Be, Zr, Nb, Ru, Rh, Ag, and
05eedrare-earth elements were predominantly found in theroots. The distribution pattern of lanthanides in theroots is similar to that for the rice plants. 1)
Soybean plants grown on the soil were harvested
about 2 months after the start of germination. The
seeds were still immature. The roots were carefullycollected and washed to remove soil. Figure 2 shows
distribution of elements among various parts of theplants. The number of elements detected in the rootsis smaller than that for soybean plants grown in the nutrient solution. Mn, Zn, Se, Rb, and Sr were found in
the stems, leaves, pods, and seeds as in the case of thehydroponic culture. However, the percentage distribution of all elements was smaller by a factor of 10- 3 10- 2 compared to that of the soybean plants grown in
the nutrient solution.

o

1.0.L..aal

0.8

t

Seed

ill Pod
E§1 Stem

II Root
0.6

GI

~

(II

c.. 0.4:::>
0.2~v~CoZnSeRbSrYZr~~~~h~~~Yb~~

EI PodElement

_Leaf

100

r:a Stem

Fig. 2. The percentage distribution of metal elements
among various parts of the soybean plant grown on soilfor 2 months.

II Root

80

C 60
~
(II

:~

g. 40
20

o

II I

I

I-

I. :m

SeSe V MnCoZnAaSeRb StY ZrNbRuRhAgTe8.C.PmEuGdYbLu HI I.

This difference is explained by the low distributionof metal ions in soil water and the dilution of radioisotopes with corresponding elements in soil. The distribution of Se is quite similar to that of essential element
Zn. This suggests that Se is required for germinationand growth of the plant.

Element

Fig. 1. The percentage distribution of metal elements
among various parts of the soybean plant grown in anutrient solution for 30 days.

84

References
1) S. Ambe, Y. Ohkubo, Y. Kobayashi, M. Iwamoto, and
H. Maeda: This report, p. 83.

RIKEN Accel. Prog. Rep. 28 (1995)

The Study of Behavior of Various Elements in Atmosphere-plant
System by Multitracer Technique
T. Shinonaga, S. Ambe, S. Enomoto, H. Maeda, M. Iwamoto, T. Watanabe, and I. Yamaguchi
The behavior of various elements in atmosphereplant system is being studied by a multi tracer technique.
In recent years, pollution in environment has become serious problems for human lives. These problems mainly occur by industrial wastes and products,
automotive exhaust gases, and soot. The recent remarkable problem is the radioisotopes leaked into atmosphere from the atomic reactors and one of the obvious example is the accident of Chernobyl Reactor
which occurred on April 26, 1986. After the accident,a large number of radionuclides were injected into theatmosphere and they brought many risks to lives especially in Europe. After this accident, many investigations have been reported for the problem of spreadradionuclides, e.g., for long-lived radionuclides such as1291 (T 1/2 = 1.6 X 107 y) in the atmosphere and therainwater. 1) These radionuclides may nfluence humanbodies directly or possibly through the plants and theanimals as food. Wagner reported the radio ecological investigation on the food-chain, such as air-soilvine-wine determining contents of 137 Cs at different
locations in Germany before and after the Chernobyl
accident. 2) These results clearly show the fact that thepollutants in atmosphere are taken in human bodies
through the food-chain.
The most of previous studies which concern the
problem of the pollution in plants were performed in
the field observing a few elements, but the mechanismof the absorption of elements in the atmosphere intoplants is not yet well known. This mechanism could
also be important for understanding a complicated circulation system of elements on the earth.
In this study the absorption of various elements inthe air by plants and soil is experimentally investigatedusing a radioactive multitracer. As the first step, therelative amount of elements absorbed in each part ofplant is determined. These results will be considered
to provide a base of estimation of the factors in themathematical model for the behavior of elements inthe plant-soil-atmosphere system. The depth-profilesof absorbed elements in soil are also analyzed.
For the production of multitracer, the Au target
irradiated with 14N at the RIKEN Ring Cyclotron
was dissolved in aqua regia and Au ions were finally
removed from the 3 mol dm- 3 HCI solution by ex-

traction with ethyl acetate, and the carrier-free andsalts-free multitracer was prepared. This multitracer
solution in an evaporating dish was put on the soil covered with parafilm in a closed (excepted a hole covered
with a glass fiber filter together with a membrane filter) acryl box. In the multitracer solution, cellulose
powder (> 300 mesh) was supplied and the solution
was dried. The used plants were Soybean and Komatsuna. They were cultivated in this acryl box installed
in a biotron with the radionuclides at 23°C under exposure of 20000 lux light of fluorescent lamps for 12 h
a day during 30-80 days for Soybean and 10-20 days
for Komatsuna, respectively. About 8 liter of air was
overblown per day at the upper and near the surface
of soil covered with parafilm to make similar condition
to floating dust. The tube for supplying water was put
under the soil to avoid the leaching effect of the elements by water, and about 100 ml of distilled water
was given per day. The monitors were similarly madeto each plant by a glass fiber filter and they were set
up beside each plant.
After the plants were grown up, they were takenout and separated each part: root, leaf, stem, seed,
pod for Soybean, and leaf and root for Komatsuna.
Some of the stems and beans were cut in inner partand outer part. After they were washed with diluted
HCI solution in an ultrasonic wave bath, the ')'-ray wasmeasured for each part of the plants.
For the depth-profiles of soil, three test tubes of 2
em dia., 14 cm height were inserted in the soil at somedistances from the dish containing the multitracer , andthe ')'-ray was measured for 2 cm depth from the surface
and further each 4 em part of depth, respectively.
The observed elements were Be, Sc, V, Cr, Mn, Co,
Zn, As, Se, Rb, Sr, Y, Ru, Ag, In, Sn, Te, Ba, Ce,
Eu, Gd, Yb, Lu, Hf, Re Ir, and Pt. The measurement
has been finished and the analysis is now being carried
out.
References
1) M. Paul, D. Fink, G. Hollos, A. Kaufman, W.
Kutschera, and M. Magaritz: Nucl. lnstrum. Methods
Phys. Res., B29, 341 (1987).
2) A. Wagner: Bundesforschungsanstalt fUr Ernahrung,Karlsruhe, Germany, p. 205 (1989).

85

RIKEN Accel. Prog. Rep. 28 (1995)

Study on Uptake and Excretion of Trace Elements in Rats using
the Multitracer Technique
M. Yanaga, S. Enomoto, R. Hirunuma, R. Furuta, K. Endo, A. Tanaka, S. Ambe, M. Tozawa,* and F. Ambe
The isotopic tracer method is useful in science, technology, medicine and many other fields. If a number ofr~dioactive tracers are used simultaneously, it is possIble to determine the characteristic behaviour of different elements under an identical experimental conditio~. In the present study, the multitracer technique,whIch was established at RIKEN a few years ago,l,2)
was applied to an investigation of the uptake and excretion behaviour of trace elements in rats.
A multitracer solution was obtained from a gold foil
target irradiated with 14N-ion beam accelerated by the
RIKEN Ring Cyclotron. The target was dissolved inaqua regia and the solution was evaporated to dry~ess. After the residue was dissolved in 3M HCI, gold
Ions were removed by extraction with ethyl acetate.
The remaining aqueous phase was again evaporated
to dryness and adjusted to pH 3 with dilute HCI for
administration to rats.
The multitracer solution was orally administered tothree seven-weeks-old male Wistar rats. A half ml of
the solution was used for each rats. Feces and urine
were collected at 8 h and then at 24-h intervals after administration. The radioactivities of them were
measured with pure Ge detectors. The spectra wereanalysed with BOB code 3 ) on a FACOM M1800 computer. The observed ,-rays were assigned to various
nuclides according to their energies and half-lives.
. I~ the multi tracer solution used in this study, radIOIsotopes of many kinds of elements were included:e.g., Be, Sc, Mn, Co , Zn, As, Se, Rb, Sr, Y, Zr, Ce,
Eu, Gd, Tb, Er, Tm, Yb, Lu, Hf, W, and Re. In Fig.
1, rates of excretion are summarised for five of thoseelements for one of the rats. Excellent agreement was
found in the excretion rates among the rats. As shownin Fig. 1, a very small amount of rhenium was foundin feces , which means that rhenium was entirely absorbed into the body. The excretion behaviour for Re
to urine was found to be quite unique. More than 80%
of rhenium was eliminated in urine within only one
day. Further experiments on elimination of rhenium
to urine showed that the excretion was composed of atleast two phases. Namely, more than 85% of Re was
excreted with a half-life of about 3 h but 3- 5% of Rewith a day-order half-life irrespective of whether a carrier material (KRe04 , 0.2 mg/rat) was included in theadministered solution or not. In those experiments,
most of rhenium remaining in the rats' body «7%)
was found in hair and a trace amount «0.01%) was
fmmel in hone.
Interesting behavIOur was also found in the excretion rate for tungsten. Fifty to 90% of tungsten wasabsorbed into the body; then, 80-90% of the absorbed
tungsten was eliminated in urine within one day. No,-rays due to tungsten were detected in any organs andDept. Chern. , The Jikei University School of Medicine

86

Feces
100

:! :

§

"E 60 ------.-~ -·1 ~-- ------,. ------- . ----- --,;

.l... .... .L. ...... ~....... .

40

~ 20

~-

24

','---

48

72

96

12 0

144

Time after administration (hour )

Urine
80

§

§ OO t ··· ~! ··~········~······ ·· : · ···· ···~········:·· ····· .. ~ . .. .... . :

~

~ 40

"0
Q)

20

i8

.;:"~ ... ~ ....';'... ; . .•. . .•• ; . ... . . . .. ~ ...... .. : ..... - ... ~ .. •. .... -

!i
I

~
~

0.~

24

48

72

96

120

144

Time after adm ini str ation (hour)Fig. 1. Rates of excretion of Sr, W, Re, Ir, and Pt to feces
and urine for one of the three rats studied.

tissues 6 days after administration.
Excretion behaviour of Mn, Co, Zn, As, Se, Rb,
Sr, Ir, and Pt is in general compatible with previous
works on uptake and excretion of these elements by
animals,4,5) which guarantees the reliability of the multitracer experiments. For example, as shown in Fig. 1,
more than 15% of strontium was absorbed and only asmall portion of it was excreted in urine. This element
was found only in bone. It is known that the gastrointestinal tract is the main route of entry into body andthe fraction absorbed via intestine is 30%, and that
99% of body burden is deposited in bone. 5)
The ,-rays due to Be, Zr, Hf and rare earth elements
were not detected in organs and tissues. There wereno peaks of these elements in any spectra of urine except for Hf which was detected in a minute amount( <0.1 %). This means that these elements were not or
only a little absorbed into rats. It is reported that gastrointestinal absorption of soluble or insoluble beryllium is thought to be minimal because the alkalinity of
the gastrointestinal tract causes precipitation of beryllium, and it is suggested that only 0.006% of ingested
beryllium was absorbed. 5 )References
1) S. Ambe et al.: Chern. Lett., 1991, 149.
2) S. Ambe et al.: Anal. Sci. , 7, Suppl., 317 (1991).
3) H . Baba et al.: J. Nucl. Sci. Technol., 8, 1227 (1972).
4) H. Sakurai and H. Tanaka eds.: Seitaibiryougenso, Hirokawa Publishing Co., Tokyo (1994).
5) H. G. Seiler, A. Sigel, and H. Sigel eds.: Handbook
on Metals in Clinical and Analytical Chemistry, Marcel
Dekker, Inc. , New York (1994).

RIKEN Accel. Prog. Rep. 28 (1995)

Multitracer Study on Distribution of Radioactive Nuclides in Rats:
Metabolism and Accumulation in Various Tissues,
Organs and Body Fluids
S. Enomoto, M. Yanaga, R. Hirunuma, K. Endo, S. Ambe, and F. Ambe
discussion are given below, with the elements being
tentatively divided into the following six groups basedon the classification of the periodic table.
(1) Rubidium (alkaline metal) was found to be distributed widely among various tissues, organs andbody fluids. High concentrations were found in liver,spleen, kidney and skeletal muscle. The chemical similarity of rubidium to potassium is considered to allow
use of the former as a substitutive tracer for the latterto some extent. These results suggest that rubidium
is essentially an intracellular ion, physiologically mostsimilar to potassium since it is distributed throughout the body in a very similar manner. Distributionof rubidium in whole blood was mostly found in erythrocytes. From this study, rubidium is found to beeliminated very slowly from the body.
(2) Strontium (alkaline earth metal) was found inhigh concentrations in bone. The result suggests thatthe distribution of strontium was similar to that of calcium. The results have also demonstrated that intestinal absorptions of strontium and calcium are comparable, which leads to the hypothesis that these elements
share a common carrier system in the intestinal wall,
probably with a greater affinity for calcium.
(3) 3d-'fransition elements such as Mn, Co, and Zn
were distributed in organs based on their individual
characteristics. Among the elements, zinc was foundin every organ as well as blood, and high concentrations of it were observed in liver, kidney and spleen.
The absorption of zinc ions mainly occurs in the small
intestine, especially in the jejunum, while its absorJr
tion in the duodenum and the stomach seems to bevery low. 2) Zinc is essential for the structure, reg-

Data obtained from radioactive tracer experimentson biological systems generally show considerable variation due to the peculiarity of individual samples. Useof a multitracer 1 ) in a given biological system enables us to obtain information on the behavior of trace
amounts of many kinds of radioactive nuclides in various tissues, organs or body fluids simultaneously understrictly identical conditions, suggesting that effects ofboth peculiarities of samples and variation in experimental conditions can be minimized.
In the present study, the uptake and distributionof radioactive isotopes in various tissues, organs andbody fluids of rats were examined by means of themulti tracer technique to clarify the behavior and roleof different elements.
Hydrochloric acid solution containing a multitracer
was prepared from gold foil irradiated with N-14 beamof 135 MeV/nucleon from RIKEN Ring Cyclotron and
was adjusted to pH 3. The solution was administered orally to Wistar rats (male) which were sevenweeks old. The rats were sacrificed after several days.
The tissues, organs, body fluids and excretions were
weighed and their radioactivities were determined by,-ray spectrometry. Identification and determinationof isotopes were done on the basis of their energies
and half-lives. The results are given in percentage oforally administrated dose per gram of tissues, organs
and body fluids (uptake rate, %/g).
From the analysis of ,-ray spectra, distributions of
23 elements, namely Be, Mn, Co, Zn, As, Se, Rb, Sr,
Y, Zr, ee, Eu, Cd, Tb, Er, Tm, Yb, Lu, Hf, W, Re, Ir,
and Pt, were determined. Typical results at 6 days after administration are shown in Fig. 1. The results and
(a)

(b)

(c)

blood

liver
kidneyintestineskeletalmusclebrain
spleentesticle
0

0.1

0.2

0.3

Uptake rate (%lg)

0.4

0

0.05

0.10

0.15

Uptake rate (%Ig)

0.20

0

1.0

2.0

3.0

4.0

Uptake rate (%lg)

Fig. 1. Uptake rate (%/g) of rubidium (a), zinc (b) and arsenic (c) in various tissues, organs and body
fluids in a rat.

87

ulation, and/or the catalytic action of many enzymes
and it influences the activity of over 300 enzymes. 3 ) In
accordance with this, we found that zinc was widelydistributed in various tissues, organs and body fluids.
On the other hand, orally administrated manganese
does not concentrate in specific organs. In general,
the absorption level of manganese is lower in animals
which have reached adulthood. 4 )(4) All the radioactivities of rare earth elements (Y,ee, Eu, Gd, Tb, Er, Tm, Yb, and Lu) and Be, Zr, Hf
were eliminated in feces. These results indicate thatthese elements were not absorbed by the digestive organs including intestine.
A detailed discussion is given in Ref. 5.
(5) Of the 5d-transition metals, W, Re, Ir, and Pt
were determined, and each was found to exhibit characteristic behavior. Intestinal absorptions of tungsten
and rhenium were rapid. They were likewise rapidlytransferred to blood and then to kidneys for filtration
and removal from the body. However, rhenium wasretained partly in rat hair 6 days after administration.
In contrast, platinum and iridium were absorbed byliver, kidney, and intestine. These metals are reported
to bind with metallothionein in liver and kidney.6) The
above result is compatible with this binding characteristic.
(6) The absorption of arsenic (group V) and selenium (group VI) was also investigated. Selenium wasfound to be widely distributed in every organ, and thehighest concentration of which was detected in kidney,
liver, blood, testicles, and intestine. Selenium is involved in some important biochemical reactions and88

is found in a number of proteins. 7 ) Accordingly, we
found that selenium was widely distributed in various
tissues, organs and body fluids. On the other hand,arsenic was found mainly in blood. Arsenic combineswith sulfhydryl groups of many enzymes. B) Arsenic is
a strong hemolytic poison, with erythrocytes being
the target. We found that arsenic is bound to pr~tein (aI-globulin) in serum and to the globulin part ofhemoglobin in erythrocytes.
These results suggest that when applied to a given
biological system, the multitracer technique is a powerful tool to obtain information on the behavior oftrace amounts of elements in various tissues, organs
and body fluids.
References
1) S. Ambe et al.: Chern. Lett., 1991, 149.
2) L. Thunus and R. Lejeune: Handbook on Metals in
Clinical and Analytical Chemistry, edited by H. G.
Seiler, A. Sigel, and H. Sigel, Marcel Dekker, New York,
p. 667 (1994).
3) R. J. Cousins: Physiol. Rev., 65, 238 (1985).
4) L. S. Maynard and D. D. Joel: Life Sci. Stal., 28, 96(1977).
5) M. Yanaga et al.: This report, p. 86.
6) R. P. Sharma and I. R. Edwards: Biochem. Pharmacol.,32, 2665 (1983).
7) R. J. Magee and B. D. James: Handbook on Metals
in Clinical and Analytical Chemistry, edited by H. G.
Seiler, A. Sigel, and H. Sigel, Marcel Dekker, New York,
p. 551 (1994).
8) R. IfRand: ibid., p. 237.

RIKEN Accel. Prog. Rep. 28 (1995)

Distribution and Behavior of Trace Elements in Zinc Deficient Rats
Using the Radioactive Multitracer Technique
S. Enomoto, M. Yanaga, R. Hirunuma, K. Endo, S. Ambe, and F. Ambe
The concentration variation of one particular element generally affects the concentrations and physiological effects of other substances, including other inorganic elements. This multidimensional interdependence has been known qualitatively for a few of elemental nutrients. 1) However, the multidimensional interdependence of many trace elements in living bodies
is still not clear. Two components can interact by mutually promoting synergistic effects or by competingand suppressing antagonistic effects. Use of a radioactive multitracer in a given biological system enables us
to obtain information on the multidimensional interdependence of many trace elements in various tissues, organs or body fluids simultaneously under strictly identical conditions, suggesting that effects of both peculiarities of samples and variation in experimental conditions can be minimized.
In the present study, the uptake and distribution ofradioactive isotopes in various tissues, organs and body
fluids of zinc deficient rats and normal rats were examined by means of the multitracer technique to clarify
the behavior and role of different elements. Zinc is thesecond most abundant transition element in the animalorganisms, following iron; zinc also plays an importantrole in many processes of metabolisms of living beings. More than 300 different zinc-proteins are known.
These include numerous essential enzymes which catalyze the metabolic conversion or degradation of proteins, nucleic acids, lipids, porphyrin precursors andother important bioorganic compounds. It is thus not
surprising that zinc deficiency leads to severe pathological effects and is expected to affect the behavior ofother trace elements greatly.
A saline solution containing a multitracer was prepared from a gold foil irradiated with N-14 beam of
135 MeV/nucleon from RIKEN Ring Cyclotron. The
solution was injected intravenously to normal or zinc
deficient Wistar rats (male) which were seven weeks
old. The rats were sacrificed after 4 days. The tissues,organs, body fluids and excretions were weighed andtheir radioactivities were determined by ,-ray spectrometry. Identification and determination of isotopes
were done on the basis of their energies, half-lives andpeak areas. The results are given in percentage of intravenously injected dose of tissues, organs and body
fluids (uptake %).
From the analysis of ,-ray spectra, distributions of
Sc, V, Mn, Co, Zn, Rb, Sr, Y, Ce, Eu, Gd, Tm, Yb,
Lu, Hf, Re, Ir, and Pt were determined. Concern-

ing the Zn distribution in zinc deficient rats, the uptakes in testicle, skin and bone were smaller than thosein normal rats; however, the uptakes in other tissues
and blood were larger. Other various trace elements
also demonstrated characteristic behavior. Noteworthy is that distributions of Pt and Ir in zinc deficient
rats are quite different from those in normal rats. In
the case of normal rats, Pt and Ir are classified in thesame behavioral group (the platinum group), because
these elements behave in a similar manner in an animal body.2) However, when we administrated them tozinc deficient rats, the uptakes of Ir in skeletal muscle,skin, hair, and plasma were larger than those of Pt
by a factor of about 2-3. These results suggest thatzinc deficiency contributes to conformational changes
or affinity changes on transport proteins or enzymes
which interrelate with the uptakes of Pt and Ir. The
distributions of various rare earth elements (REE) exhibited similar behavior in both normal and zinc deficient rats. The uptakes of REE in various tissues,
such as liver and kidney, were correlated with changes
in the ionic radius of REE. The uptakes of "light" REE
increased with increasing ionic radius, however, there
were not a marked tendency in those of "heavy" REE.
These results suggest that the uptakes of light ,REE,
whose ionic radii are near that of calcium, are interrelated with the calcium transport systems in cytoplasmic membrane. In contrast, the uptakes of REE inbone were different from those in other tissues. The
heavy covalent REE in bone were accumulated to agreater extent than the light REE. The uptakes oflight REE were decreased with increasing ionic radius.
These results also indicate that heavy covalent REE
are adsorbed on hydroxyapatite that reacts with enzymes such as alkaline phosphatase and light REE are
non-specifically adsorbed on connective tissues in surface of bone.
These results suggest that when applied to a given
biological system, the multi tracer technique is a powerful tool to obtain information on the behavior of trace
amounts of elements and the multidimensional interdependence of various elements in various tissues, organs
and body fluids.
References
1) H. Sigel, A. Sigel, and H. G. Seiler: Handbook on Metals
in Clinical and Analytical Chemistry, Marcel Dekker,
New York, p. 1 (1994).
2) K. H. Konig and M. Schuster: ibid., p. 521.

89

RIKEN Accel. Prog. Rep. 28 (1995)

Tissue Distribution of 16 Elements in Mice: An Application ofMultitracers to Animal Experiments
R. Amano, M. Nobuta,* M. Sakamoto,* R. Tsujioka,* S. Enomoto, and F. Ambe
We are now developing the radioactive multitracer
technique in the metabolism study of a number of traceelements in animals. First we examined here the tissue distribution of carrier-free multitracers in mice anddiscuss on their usefulness in animal experiments.
A multitracer solution was obtained from the silver foil target irradiated with 14N beam accelerated
in RIKEN Ring Cyclotron. The preparation procedure was given elsewhere. 1,2) After evaporation of thecarrier-free multi tracer solution containing hydrochloric acid, a physiological saline solution was added toprepare the multitracer solution for injection. Male
ddY mice (body weight 25-35 g) were injected intraperitoneally with 0.2 mL of the final preparation.
At 4 different time, namely, 3, 24, 72, and 168 hr after administration of the multitracers, the mice were
killed under ether anesthesia and approximately 0.3
mL of blood was collected. After this, brain, cardiac
muscle, lung, liver, spleen, pancreas, kidney, skeletal
muscle and bone were excised. These tissues and theblood were weighed immediately and freeze-dried. The
dried tissues and blood samples were measured by "(ray spectrometry with pure Ge detectors against an
appropriate standard to obtain the percentage of injected dose per gram of tissue (%dose/g). The radionuclides were identified by the "(-ray energies andhalf lives. Tissue distribution of the radionuclides wasevaluated in terms of the percentage of injected dose
per gram of tissue (the tissue uptake rate, %dose/g).
The tissue uptake rates of Be, Sc, V, Cr, Mn, Fe,
Co, Zn, As, Se, Rb, Sr, Y, Zr, Ru, and Rh were obtained for the 9 tissues and blood in mice. We now
brief some preliminary results concerning vanadium as
an example. Table 1 summarizes the tissue uptake
rates of radioactive V in the tissues and blood. Eachvalue represents the mean of four mice. Figure 1 shows
the time course of the uptake rates for 4 tissues. The
values for bone at 24, 72, and 168 hr after injection
Table 1. Tissue uptake rate of radioactive V in mice at 3,
24, 72, and 168 hr after intraperitoneal injection.
Tissue

v

3 hr
24 hr
72 hr
168 hrBlood
2.94 ± 0 . 15 0.86 ± 0 .19
n.d.
n.d.
Brain
0.09 ± 0 .05 0 .06 ± 0 .00
n.d .
n.d.
Cardiac muscle 0.84 ± 0 .28 0.74 ± 0.10 0.47 ± 0.16 0.34 ± 0.11
Lung
1.09 ± 0.21 0 .66 ± 0.11 0.35 ± 0.06 0.22 ± 0.04
Liver
2.53 ± 0.63 1.50 ± 0.24 0.79 ± 0.12 0.76 ± 0.26
Spleen0.48 ± 0 .17 0 .69 ± 0.28 0.51 ± 0.23 0.24 ± 0.09
Pancreas
0 .64 ± 0.23 0.55 ± 0.27 0.42 ± 0.17
n .d.
Kidney6.47 ± 1.83 2.28 ± 0.35 1.86 ± 0.05 0.83 ± 0.19
Bone
3 .65 ± 0.90 6.03 ± 1.58 8.73 ± 2.24 5.65 ± 1.58
Skeletal muscle 0.61 ± 0.13 0.27 ± 0.17 0.24 ± 0.03 0.15 ± 0.03
n.d .: not detected

School of Allied Medical Professions, Kanazawa University

90

were 6.03, 8.73, and 5.65 %dose/g, respectively. These
values were much larger than those for other organs.
Vanadium is not generally noted as a bone-seeking element. The multi tracer technique enables simultaneous
tracing of other elements concerned with bone and extensive comparison of these elements under a strictly
identical condition. 3 ) Figure 2 compares the bone uptake rates of V, Sr, Zr, Y, Rh, Ru, and Se. The valuesof V resembled those of Sr, Zr, and Y, but not those of
Rh, Ru, and Se. From these results it has been foundthat vanadium may play an important role in the bonemetabolism. We have mainly mentioned above the results concerning vanadium as an example. We reallyobtained similar results on 15 other elements in thepresent work, which will be reported and discussed
later.
10.00

~
~

~

Aloney

~~

~.~

1.00

..

~

f

-=!

Skeletal Muscle

uo

--g

~

0.01

o

50

100

150

200

Time (br)Fig. 1. Time course of the tissue uptake rates of radioactive V in mice.

j I.

.

~

I

..,[]"

~
'r'

.A

.1

•

IIh

I ..

1541

Time (br)Fig. 2. Time course of the uptake rates of V, Sr, Zr, Y,
Rh, Ru, and Se in mouse bone.

In conclusion, we want to emphasize the advantagesof the multi tracer technique over the conventional single tracer technique: the multi tracer method enables
simultaneous tracing of many elements in the identicalorgan and a strict comparison of their biobehavior.
References
1) S. Ambe et al. : Chern. Lett., 1991, 149.
2) S. Ambe et al.: Anal. Sci., 7, Suppl., 317 (1991) .
3) F. Ambe: RIKEN Review, No.4, p. 31 (1994) .

RIKEN Accel. Prog. Rep. 28 (1995)

Studies on Transcuticular Movement of Multitracer fromPlant Leaf Surfaces
T. Watanabe, K. Matsumoto, S. Ambe, and 1. Yamaguchi
The surface of plants is generally covered with cutile which plays an important role in their growth forprevention of transpiration, invasion of microbes andforeign substances and for morphogenesis. The transcuticular movement of radionuclides as a foreign substance is an interesting matter relating to the uptake,
distribution and accumulation in plants via rainfall of
those contained in fall-outs.
To investigate the transcuticular penetration andtranslocation of radionuclides on/in plants, the authors
have carried out a preliminary study of the transcuticular movement of 137 Cs applied as an aqueous droplet
onto the leaves of chinese cabbage. The result showedthat 137 Cs firstly penetrated into the cuticle under the
droplet, then passed across it to trans locate inside theleaf tissue acropetally and basipetally, and finally distributed in the stems, leaves and roots other than theleaf applied. To analyze quantitatively the translocation proccesses of various kinds of radionuclides, fiveILl of the multitracer solution was applied onto the leaf
surfaces of chinese cabbage and mugwort at the fifth
leaf stage. Then, the amounts of each radionuclide
in the malutitracer translocated into the fractions of
cuticle, applied leaf, other leaves and roots were periodically measured. The calculation is now underway
using computers.

91

RIKEN Accel. Prog. Rep. 28 (1995)

Simultaneous Analysis of Solid-Liquid Adsorption Behavior of
Various Elements using Radioactive Multitracer:
Activated Carbon Fiber and Non-ionic Macro-reticular Copolymer
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. 1 ,2) We reported previously the adsorption behavior of 36 inorganic elements on Kynol ACF-1605-15 (novoloid-based
activated carbon fiber) and Amberlite XAD-7 (nonionic MR copolymer) in 0.01- 10 mol·dm- 3 solutionsof HCI and LiCI using a radioactive multitracer prepared by irradiation of Au or Ag foil with a heavy ion
beam. 3 )We continued the study on the adsorption behaviorof various elements on these adsorbents using a multitracer obtained from irradiated Fe foil. In separation of
the reaction products after the irradiation of iron with
135 MeV /nucIeon 16 0 6 + , iron was extracted with isopropyl ether from 8 mol·dm- 3 HCI. The aqueous layer
was evaporated to dryness. The residue was dissolvedin 1 mol·dm- 3 HCI. Other experimental methods werementioned in a previous report. 3 )Figure 1 shows the adsorption profiles of 42 elements
in log-log plotting of Kd against the concentration of
CI- . The authors are now studying the adsorption behavior of other elements using the multitracer preparedfrom other targets, such as Zn and Sn.
log KdUD<aJ ACF-160S-1S

Na Mg _

:0 00000

loglCI·,

·2·,

0

,

AI Si

P

S CI

Q D ~ D ~ ~~D gDDDgDg8D
K Ca Se Ji

V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br

Q g§D B uD~B B~D8D~~D
Rb Sr Yf:r Nb Mo Ie

CS Ba

Hf Ta

Ru Rh Pd Ag Cd In Sn Sb Te I

D B~U ~D~D8~DDDDDD
W
as
Re

Ir

Pt Au Hg TI Pb Bi Po

EJD[]lsjD[]BEJDDBBEJ[]DO
DDDDD
La Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu(b) XAD-7

Na Mg

AI Si

P

S

CI

DD ~ D~DQ D ~ DDDDDD~D
K Ca Se Ti

V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br~D~8 ~ ~B~~~ QD D D~~D
Rb Sr YZr Nb Mo Te Ru Rh Pd Ag Cd In Sn Sb Te I

D~
~ gbJDESJ[s]bJbd
DDDDDDCs Ba
Hf Ta W Re as Ir Pt Au Hg TI Pb Bj Po

DDbJbJDDDDDDDbJbJQ

La Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu

Fig. 1. Effect of Cl- concentration in HCl (- ) and LiCl (... ) on Kd values of elements
for ACF-1605-15 (a) and XAD-7 (b).

References
1) K. Watari, K. Imai, S. Shibata, and M. Miura: J. At.
Energy Soc., Jpn., 26, 384 (1984) .
2) S. Shibata, K. Watari, and K. Kaneko: Radioisotopes,
National Institute of Radiological Sciences

92

39, 26 (1990).
3) S. Shibata et al.: RIKEN Accel. Prog. Rep., 27, 83(1993).

RIKEN Accel. Prog. Rep. 28 (1995)

Studies on the Ion Exchange Adsorption Behavior of Strongly
Acidic Resin NAFION and its Application to
Analytical Chemistry
N. Ito, H. Harakawa, Y. Saito, K. Kimura, S. Ambe, M. Iwamoto, H. Maeda, and F. Ambe
Radioactive multitracer solutions, in a carrier- andsalt-free condition, prepared from gold l - 5 ) foil irradiated with 135 MeV/nucleon 14N ions were used for thetitled studies in a NAFION-HN0 3 system after being converted to a nitric acid solution. The NAFION501 resin, manufactured by DuPont, is a perfluorinatedpolymer containing ,,-,5 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
50-120 mesh screen, and used. Into a small polyethylene bottle, 0.1 ml of the multitracer solution and 2.4 gof the resin were introduced, and the acidity of the system was adjusted to 0.1, 0.3, 1, 3, 5, and 10 mol dm- 3
with nitric acid and distilled water, thereby making
the volume of the solution to 10 ml. The contents ofthe bottle were shaken vigorously at 25°C with an 8shape mode shaker. Time of the shaking was 75 hours.
After filtration, ,-ray spectrometry was carried out for
both phases.
The distribution ratios (D) of alkali metal, alkaline
earth metal and rare earth element (Fig. 1a) were obtained, decreasing with slopes of the valence number on
log-log plotting as nitric acid concentration increased,
which is characteristic of the ion exchange. D's for Hf
and Zr (Fig. 1b) were relatively low at 0.1 mol dm -3 nitric acid concentration, while in other concentrations,those decreased with slopes of - 2 approximately. It
is thought that Hf and Zr mainly exist as Hf0 2 + and
Zr0 2+ in 0.3,,-, 10 mol dm- 3 nitric acid concentrations
and the low D values at 0.1 mol dm- 3 concentration
would be due partially to their hydrolytic species.
An ion exchange separation using a NAFION resin
column was carried out with 0.1,0.3, and 5 mol dm- 3
nitric acid concentrations. Twelve % of Hf and 5% of
Zr were eluted at 0.1 mol dm -3 nitric acid without adsorption, corresponding to the above lower D values at
low concentrations of nitric acid. Pt (60%) was also
passed through the column. Alkali metal and alkaline
earth metals were separated from each other in orderof D values at 0.3 mol dm- 3 nitric acid, and finallyother multi-valent elements including rare earths and

105
104 ~

(a)

103

•

10 ~
10 1
2

0

" Rb-84o Sr-85• Ce-139

Q

10°
10- 1

".

il

10-2
0.1
10 2

1

(b)

HNO/M)

10• Hf-175
Zr-88

•

I -

10 1 ,

0

0

• .~

!

~

/~

1

-2

'. •
--..3,

10- 1
0.1

:'.

1

HN0 3(M)•10

Fig. 1. Relationship between D and acidity of nitric acid.
(a) Rb, Sr, and Ceo (b) Zr and Hf.

the rest of Hf and Zr were eluted at 5 mol dm -3 .
References
1) S. Ambe, S. Y. Chen, Y. Ohkubo, Y. Kobayashi, M.
Iwamoto, M. Yanokura, and F. Ambe: RIKEN Aceel.
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 Aceel. Prog. Rep., 24,
73 (1990).
4) S. Ambe, S. Y. Chen, Y. Ohkubo, Y. Kobayashi, M.
Iwamoto, M. Yanokura, and F. Ambe: Chern. 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).

93

RIKEN Accel. Prog. Rep. 28 (1995)

Influence of Metal Humate Formation on the Adsorption ofMultitracer on Kaolinite
Y. Takahashi, Y. Minai, S. Ambe, M. Iwamoto, H. Maeda, F. Ambe, and T. Tominaga
Humic acid, a naturally-occurring organic polyacid,is soluble in neutral aqueous solutions and capable offorming stable complexes with some cations through avariety of its functional groups. Therefore, humic acidmay influence migration in the environment of metal.
. Ient actInl"des. 1,2)
cations such as lanthamdes
and tnva
We have used the multitracer technique to study interactions between various ions and humic acid. 3 ) Kaolinite is a typical clay mineral which adsorbs metal cationsin the environment. The presence of humic acid inaquifer, however, may reduce the adsorption of ionson kaolinite by complex formation. The influence ofhumate formation on the adsorption of multitracer on
kaolinite is given in this report.
Multitracer was produced by spallation reaction of
Au with 12C or 14N at RIKEN Ring Cyclotron and was
prepared as 3 M HCI solution. 4,5) The HCI solution
was converted to 0.001 M perchloric acid solution for
the following experiments. Humic acid solution (5 mf,
50 mg/f), kaolinite (10 mg), and multitracer solution
were mixed and shaken for a week. After centrifugation, the aqueous phase was filtered with a membrane filter (pore size, 0.45 /-lm). Then l'-ray spectraof the filtrates were recorded with a pure Ge detector
coupled with a 4096 channel multi-channel analyzer.
Photopeak intensities of the radionuclides in the aqueous phase were determined with a routine (BOB) on
a FACOM M780 computer. Percentages of the dissolved species of Co, As, Rb, Sr, Y, Zr, Ag, Ba, Ce,
Eu , Gd , Yb , Lu , Hf, Re , Ir, and Pt in each sample wereobtained by comparing the photopeak intensities withthose for the multitrader solution injected.
In all samples, humic acid was also adsorbed on
kaolinite,6) and fractions of dissolved humic acid were
. 1y as s hown In. p'19. 1 .7)
obtained spectrophotometncal
Rubidium (alkali metal), and As or Re (forming
oxoacids) were not adsorbed on kaolinite; additionof humic acid did not affect their adsorption ' behavior. This indicates that those ions do not make complexes with humic acid. Barium (alkaline-earth metal)
may be partially present as a humate complex, since
the pH dependence of Ba adsorption was almost similar to that of humic acid: the percentage of the dissolved species decreased at pH = 4-5 and increased at
pH> 7. Yttrium and the lanthanides (Ce, Eu, Gd, Yb,
Lu) form stable complexes with humic acid, since theirdissolved percentages were identical with those of humic acid. Both humic acid and the rare earths were adsorbed in low pH region and were dissolved at pH > 6.
The presence of humic acid made the pH dependenceof adsorption of rare earths the opposite to that in the

94

000

100

~

0

"C

'u
n:s

....

..

. ..

.'\

()

0

'E

:::I

s=

(5

..

50
0

j:
"C

a>

0

>
'0
I/)
I/)

01-

0

0

0

o~

0

0

0

0

0
0

0

0

.co 00 0 0 0
4

0

6

8

10 -

10

pH

Fig. 1. Percentages of dissolved species of Hf and humic
acid when the following solution (5 mR) was contactedwith kaolinite (10 mg). (0: without humic acid, 0:
humic acid was added after addition of Hf, 0: humic
acid was added before addition of Hf, e: humic acid)humic acid-free system. It means that the interactionof the clay mineral with humic substances modifies theadsorption property of the mineral. As shown in Fig.
1, humic acid apparently enhances the dissolution of
Hf- identical results were obtained with Zr. However,m~ch less amount of Hf or Zr was dissolved when humic acid was added after Hf or Zr had been adsorbed
on kaolinite. Adsorption behavior of the tetravalentions differs from that of rare earth ions: dissolved fractions of rare earths were identical irrespective of theorder of addition of humic acid and tracers. It suggests that a surface complex of Hf or Zr on kaolinite
is more stable than a humate complex. When humic
acid is added before the addition of tracers, the humic
acid coating on kaolinite may prevent adsorption of Hf
or Zr on kaolinite. These results show that Hf or Zr
exists as a hydrolyzed species in the aqueous phase,or on kaolinite. Humic acid indirectly influences theadsorption behavior of Hf and Zr on kaolinite.
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.,
186, 129 (1994).
3) Y. Minai et al.: Proc. Int. Trace Anal. Symp., p. 71(1994).
4) S. Ambe et al.: Chern. Lett., 1991, 149.
5) S. Ambe et al.: Anal. Sci., 1, Suppl., p. 317 (1991).
6) Y. Takahashi et al.: Mat. Res. Soc. Symp. Proc., inpress.
7) Y. Takahashi et al.: in preparation.

RIKEN Accel. Prog. Rep. 28 (1995)

Adsorption Behavior of Lanthanides Affected by
Humate-complex
T. Ozaki, Y. Takahashi, Y. Minai, S. Ambe, M. Iwamoto, H. Maeda,
F. Ambe, and T. Tominaga
Humic acid is a naturally-occurring polyacid which
can combine with various metal cations. The polyacid
may greatly influence the distribution of several metals
in the environment. We have studied the adsorption
behavior of several metal ions on hematite and the influence of metal humate formation on the adsorption
by using the multitracer technique. The multitracer
technique permits us to ditermine the characteristic
behavior of different element s under strictly identicalexperimental conditions and to make a precise comparison of the adsorption behavior among them.
A multitracer solution (3M HCI) was obtained froma gold target irradiated with a 12C beam accelerated
with RIKEN Ring Cyclotron. After evaporating up
the multi tracer solution to remove hydrochloric acid,O.OOIM perchloric acid was added to prepare the multitracer solution for further experiments. Hematite (QFe203) was added to a solution containing a multitracer. The pH of the solution was adjusted with dilute
NaOH or HCI0 4 . The suspended solution was shaken
for 1 week at room temperat ure. After centrifugation,
the supernatant solution was filtered by a membranefilter (0.45 urn) to remove Q-Fe203 thoroughly. The,-ray spectra of the supernatant were measured witha pure Ge detect or coupled with a 4096-channel multi
analizer.
In Fig. 1 is shown the pH dependence of adsorptionof Rb and Eu. In the absence of humic acid, Rb was
not adsorbed significantly on hematite in the pH range
studied. Europium attained complete adsorption in
the alkaline region. In Fig. 1 (b and d) were shown adsorption curves of Rb and Eu in the presence of humic
acid in the init ial solution studied. Humic acid was
almost adsorbed in the acidic pH range and decreased
its adsorpt ion with the increase in pH. Comparison ofthese adsorption curves with those of Rb and Eu in theabsence of humic acid indicated that the adsorption of
Rb was not infulenced by the addition of humic acid
while the adsorption of Eu became similar to that ofhumic acid. Similar results were obtained for the otherlanthanides acquired by the multitracer method. The
observed behavior of lanthanides may suggest the highstability of humate-complexes in solution.

(a) 100

;j
C

80

0

60

0

40

E.
(J)

"0

<l::

20

0

00
00 0 0

0

co

0

0

0

00 0

r.

0

15

10

(b) 100

.4

;? 80

~
C
0

..

60

+="
Q.

0

40

(J)

"0

«

0
0

20

0
0

0

~ »1

01-

~o~

0

10

pH

:(c) 100
~

80

.9

60

0

40

C

e-

~

<l::

0
20
0

go

?i

80

0

60

10

0

(d) 100

C-

0

o

0

.4

0

0

0

.(9

(J)

<l::

20

Co
.

o/'

.." .

.4

0

15

-~

E. 40
"0

r9

00
0

en

"0

15

0

10

15

pH

Fig. l. Adsorption of Rb, Eu (0) and humic acid (A) on
hematite (hematite: 100 mg; volume of solution: 4 mf)
Rb(a) and Eu(c) in humic acid free solutions; Rb(b)and Eu( d) in humic acid solutions.

95

RIKEN Accel. Prog. Rep. 28 (1995)

Production of Multitracer Nuclides by Irradiation
with an 40 Ar Beam
M. Iwamoto, S. Ambe, Y. Ohkubo, Y. Kobayashi, H. Maeda, and F. Ambe
At present, lighter heavy ions such as C, N, ando are used in combination with Ge, Ag, and Au targets in production of multi tracers by RIKEN Ring
Cyclotron. I - 6 ) In this method, 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 expected that a large part ofproduct nuclides are recoiled out of the target and canbe collected by catcher foil placed behind the target.
Using appropriate catcher foil of a common material,
the same simple separation method is available for different targets. Last year we reported the results of anexperiment with a 8 4Kr beam. 7) This year irradiation
with an 40 Ar beam was studied.
The target was Ag-, Ta-, and Au- foil and the catcher
was 25 mm-thick Al foil. The target assemblies were irradiated by 40 MeV/nucleon 40 Ar 15 + ions using Falling
Ball Irradiation System. 1) The average beam intensity
was about 10 enA and irradiation time was 40-60 min.
Details of experimental conditions for the targets are
summarized in Table 1.

catcher foil divided by the total yield for Cu-, Ag-, andAu-target respectively. The high yield of 24Na in thecatcher foil is ascribed to fragmentation of 27 Al nuclei
in the foil. These preliminary results already demonstrate the effectiveness of this catcher foil method.
Table 3. Percentage of radionuclide found in Al catcher
foil for Ag target.
Nuclide
Na-24
As-71
As-72
Se-73
Br-77
Kr-79
Rb-81

Thickness

Duration

eu
Ag
Au

(JLm)
20
10
25

(h)
0.67
0.67
1.00

NuclideNa-24
Mg-28d
Sc-44meu-67
Zn-69m
As-72
Se-73
Br-77
Y-87m
Zr-89
Nb-90
Mo-93mTotal amountof electricity
(JLe)
10.1
14.2
41.7

After the irradiation, the target and catcher foil wereanalyzed by direct "'I-ray spectroscopy with pure Gedetectors. Yield calculation of product nuclides wasmade by BOB code8 ) and related programs. Assignment of the nuclides was performed on the basis of theenergy of "'I-rays and half-life.
Tables 2, 3, and 4 show the percentage of radionuclides found in the Al catcher foil, that is, the yield in
Table 2. Percentage of radionuclide found in Al catcher
foil for eu target.
NuclideNa-24
Sc-44d
Sc-47
Mn-52

96

%
100*
37
28
22

Nuclide
Sr-83
Y-87m
Zr-86
Zr-89
Nb-90
Ru-97
Rh-101m

%
29
25
28
31
21
12
8

Table 4. Percentage of radionuclide found in Al catcher
foil for Au target.

Table 1. Irradiation conditions.
Target

%
93*
34
36
35
30
79
29

%
93*
100
100
100
100
22
18
100
100
20
20
20

NuclideTe-119Xe-125
Cs-129La-132Ce-135
Gd-147
Dy-155Dy-157
Er-160d
Tm-165
Hf-173

%
17
12
25
16
14
15
16
16
10
13
6

* 24Na produced from the catcher foil is included.

References
1) S. Ambe et al.: Chern. Lett., 1991, 149.
2) S. Ambe et al.: Anal. Sci., 7, Suppl., 317 (1991).
3) M. Iwamoto et al.: ibid., p. 313.
4) S. Ambe et al.: Appl. Radiat. Isot., 43, 1533 (1992).
5) S. Ambe et al.: Radiochim. Acta, 63, 49 (1993).
6) S. Y. ehen et al.: J. Radioanal. Nucl. Chern. Lett., 186,
113 (1994).
7) M. Iwamoto et al.: RIKEN Accel. Prog. Rep., 27, 79(1993).
8) H. Baba et al.: J. Nucl. Sci. Technol., 8, 1227 (1972).

RIKEN Accel. Prog. Rep. 28 (1995)

Target Residues from the Interaction of Copper with
40 MeV/nucleon 40 Ar Ions
W . Li,* X. Yin,** S. Ambe, Y. Ohkubo, Y. Kobayashi, M. Iwamoto, H. Maeda,
X. Zhang,** Q. Luo,** and F. Ambe
The interaction of hatural copper with lighter heavyions, 12C and 2oNe, of intermediate energy has beenstudied systematicallyl-3) with I-ray spectrometry. In
this work we extend the similar measurement to theinteraction of copper with 40 Me V jnucleon 40 Ar ions.
Irradiation was performed on the RIKEN Ring Cyclotron. By using the thick-target thick-catcher foil
technique, cross sections and average forward ranges,
FW, were determined for the target residues. Further
analysis of the experimental data was carried out in theInstitute of Modern Physics, Academia Sinica, China.
In terms of an assumption on Gaussian charge distribution, the mass yield distribution was calculated
from the cross sections of the target residues. In 12C
induced reaction of copper over a 20- 45 MeV jnucleon
energy' range, we utilized the fireball model to generate the mass transfer, the momentum transfer and theexcitation energy for each process of complete and incomplete fusion. When coupled with the sequential
binary decay model, GIMINI code, the theoretical calculations were in good agreement with the mass yield
distribution measured experimentally. In this work asimilar calculation was carried out. However, theoretical calculations, as seen in Fig. 1, failed to reproduce
the experimental mass yield distribution from the 40 Ar+ natcu reaction at 40 MeV jnucleon.

using, the ZBL transport equation. Resulting v / / IvcN
values are shown in Fig. 2 as a function of mass loss,
tJ..A, from the target, where VCN is the velocity of thepresumed nucleus. Following Ref. 1 and Ref. 3, themaximum recoil velocity corresponding to central collision was extracted from Fig. 2. Assuming that theintermediate energy heavy ion reaction could be depicted as an incomplete fusion process, a preliminary
mass of the composite system was deduced from thefractional velocity transfer v / / jVCN ' Thus the linear
momentum transfer was obtained. The fractional linear momentum transfer corresponding to central collision was calculated to be 0.30 for the collision of copper with 40 MeV I nucleon 40 Ar ions. When comparedwith the similar results from the collisions of copperwith 12C and 20Ne ions, it is found that the fractional
momentum transfer corresponding to central collisions
decreases with increasing projectile mass at the same
projectile velocity. However, the linear momentum
transferred from the projectile to struck nucleus for thecollision with 40 Ar ions is higher than those in cases of
12C and 20Ne ions. As a result, the maximum nuclear
temperature in central collisions reaches the value ofabout 5.5 MeV.

0.5

!

0.4

1000 :

is

~

:0.s
,

>:::::

0,3.§ 100 .

0.2 r-

ig:

0.1 r-

o

U 10

0

0

02r fl~ oQ 022

1

2 oQO
10

15

20

25

30

35

JJA
1 ~~~~~~~~~~~~~~~
70
60
10
20
30
40
o
50

Mass number A

Fig. 1. Mass yield distribution in 40 Ar + natcu reaction(solid line is the calculations with the GIMINI code).

To estimate the linear momentum transfer in the collisions with 40 Ar ions, the FW values were converted torecoil velocities of the residues, v / /' in initial collisions

Fig. 2. Fractional velocity transfer v / ;/VCN as a functionof mass loss, 6.A, from the target.

References
1) L. Pienkowski et al.: Phys. Rev., C43, 1331 (1991).
2) J. P. Whitfield et al.: ibid., C47, 1636 (1993).
3) L. Wenxin et al.: submitted to Phys. Rev., C.

Shanghai Institute of Nuclear Research, Academia Sinica,
China
Institute of Modern Physics, Academia Sinica, China

97

RIKEN Accel. Prog. Rep. 28 (1995)

The Mass Yield Distribution of Target Residues from theInteraction of Iron with 135 MeV/nucleon 12C Ions
Z. Qin,* W. Li,** L. Zhao,* W. Wen,* Q. Luo, T. Sun,* S. Ambe, Y. Ohkubo, M. Iwamoto,
Y. Kobayashi, H. Maeda, and F. Ambe
Nuclear reactions induced by intermediate-energy
heavy ions have been extensively investigated. The
mass distribution of target residues is one of the mostimportant characteristics of nuclear collisions induced
by energetic heavy ions. In this work, the mass yield
distribution of target residues has been studied for theinteraction of iron with 135 MeV/nucleon 12C ions.
The experiment was performed on the RIKEN Ring
Cyclotron. The target stack consisted of three pieces
of "'15.7 mg/cm 2 thick natural iron foil. The purity oftarget material was 99.9%. The stack was mounted ina ball made of aluminum and set in the irradiation siteof the Falling Ball Irradiation System. Following theirradiation, the middle target foil was assayed with acalibrated HPGe ,-ray spectrometer at RIKEN. The
data process was completed at the Institute of Modern
Physics, Lanzhou, China.
The mass yield distribution was obtained from themeasured cross sections on the basis of the Gaussian
charge distribution. The experimental results are compared with calculations based on the statistical multifragmentation model 1) (Fig. 1) and the modified sequential binary decay model 2) (Fig. 2), respectively.
The calculations based on both of the theoretical models agree with the experimental mass yield distribution.
It indicates that the target residues (A > 40), being
described by using statistical theory, originate from thedecay of equilibrated compound-like nuclei. This is thecommon basis between the two models. The largest
difference between the two theoretical models lies in
the prediction concerning mass yields in a lower mass
region (A < 30). It is interesting that the experimental
mass yields at this region are slightly lower than calculated results of the fusion fragmentation model considering multifragmentation, while higher than those of
the sequential binary decay model. Similar to a lot ofphysical experiments, the radiochemical measurements
based on off-line , ray spectra can hardly distinguishthe validity of the sequential binary decay model andthe multifragmentation model in the description of disassembly of hot nuclei. The deviation described above
perhaps confirms that the intermediate mass fragments

Institute of Modern Physics, Academia Sinica, Lanzhou,
China
Shanghai Institute of Nuclear Research, Academia Sinica,
Shanghai, China

98

with a mass number less than 30 are the source ofmultifragmentation in the disassembly of hot nuclei.
This issue is worthy of further study.

135MeV / u 12C + Fe

Q

o

10

20

30
A

40

50

60

Fig. 1. Comparison of experimental results with the fusion
fragmentation model (as histogram).

135MeV / u

12c + Fe

1000

100
j)

.§.
\?

10

o

10

20

30
A

40

50

60

Fig. 2. Comparison of experimental results with the modified sequential binary decay model (as histogram).

References
1) S. Benhao, Z. Yuming, and Z. Xiaoze: Phys. Rev., C40,
2680 (1989).
2) R. J. Charityet al.: Nucl. Phys., A340, 371 (1988).

RIKEN Accel. Prog. Rep . 28 (1995)

Angular Distribution of Recoil Products in the Heavy-Ion
Reaction of Gold
M. Furukawa, A. Shinohara, K. Mukai, T. Muroyama, A. Yokoyama, S. Kojima,
T. Saito, Y. Ohkubo, and F. Ambe
Angular distributions of recoil products were measured for the heavy-ion reaction of gold at the E3bcourse of the RIKEN Ring Cyclotron. The target was
self-supporting 240 J-Lg/cm 2 -thick Au metal foil madeby a spattering method, and set at the center of a Lucite cylindrical chamber, in the interior of which Mylar
film was put on to catch the recoil products. The ionsused were 35 and 95 MeV/nucleon 40 Ar and 70 and 135
MeV /nucleon 14N. The irradiations were done for 3 to
4 hours in the beam current ranging from 50 to 200
enA. The catcher foil was divided into 8 peaces .along
the scattering angle, and subjected to the off-line I'-raymeasurement.
The relative angular distribution of the recoil product was obtained from the main I'-ray intensities observed in the individual catcher foils. The results
for the Au + 14N (135 MeV/nucleon) system were
presented in Fig. 1 for some products in peripheral,
spallation and fission reaction regions. The angular
distributions for the peripheral reaction (target like
products) showed side peaking distribution; those forthe spallation region had a narrow forward peak; theproducts mainly from fission were distributed overa wide angle. The data analysis is in progress for

35 and 95 MeV /nucleon- 40 Ar and 135 MeV /nucleon14N beam experiments, and the measurement has been
still continued for a 70 MeV /nucleon- 14 N beam experiment.
We have data for the mean recoil ranges measured
in the previous experiments,l) which are available for
estimation of the mean linear momentum transfer tothe product. We can deduce the moving frame angular distribution from the momentum transfer if having obtained the velocities of the recoil product in themoving frame. Figure 2 shows preliminary results forthe translated distributions in the fission region. In
this analysis we assumed the total kinetic energy ofthe fission fragments obtained by Viola's systematics.
Some distributions showed 90° symmetric shape, andthe other ones were distorted shape. The 90° symmetric distribution corresponds to the slow fission passing
through the equilibrated intermediate nucleus, while
the distorted one may result in the fast fission. However, further consideration on the translation method
for the moving frame in addition on more detailed data
analysis will be required in order to discuss the property of fission in this energy region.
10 0 . - - - - - - - - - - - - - ,• Y-87g

o Tc-96g

••

• •

~ !;l

ED

•

~

• • •

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& ~

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<I>
&

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f
<I>
&

t

&

Tb-155<> Ta-175•

Os-183m

0

.I.

4>
~

~

i

t
~<D<D
(])

••• •
o

30

<>
£

~

•

t

tf

f tf
• • •

1

0 0 0

0

• Y-87g
o Tc-96g&

Rh-101m<> In-110B

60 90 120 150 180
Angle [deg.]

0

0

1

tf

? ??

• •••

0.1 '--'-............~........................~............-'----'---'----'----'
o 30 60 90 120 150 180

La-1 43o Gd-149

0

& & &

i

••• •
•

~

•• ~
•
•

.&

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rn

t ,f t f0&*0&0

o In-110B

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£ £

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... Rh-101m

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8(MF)

Fig. 2. Moving frame angular distributions for the products in the fission region.

Such a fission process, as well as the competition
with the spallation reaction, provides important information on the mechanism of hot nucleus formation in
the collision step and the succeeding equilibrium stateor its decay process. We will discuss the above fromthe beam and energy dependence of the angular distribution, which will be obtained in the present experiments, and from the mean recoil ranges and mass yield
distributions measured previously.
References

Fig. 1. Angular distributions of the recoil products in the
Au + 14N (135 MeV/nucleon) system.

1) E. Taniguchi et al.: Radiochim. Acta, 62, 163 (1993); J.
Kurachi et al.: RIKEN Accel. Prog. Rep., 26, 94 (1992).

99RIKEN Accel. Prog. Rep. 28 (1995)

Incomplete Fusion of the 141 Pr Induced by
38-95 MeV lu 40 Ar Ions
K. Mukai , A. Yokoyama, T. Saito, H. Baba, Y. Ohkubo, A. Shinohara, and M. Furukawa
We have studied the 141 Pr + 40 Ar reaction at various energies ranging from 38 through 95 MeV/nucleon,
and found that the incomplete fusion plays an important role in the intermediate energy region (2030 MeV/nucleon). We performed the experiments at
RIKEN Ring Cyclotron by the radiochemical methods. 141 Pr foils were bombarded with 40 Ar ions at
beam energies of 38, 59, and 95 MeV/nucleon. After the irradiation, the samples were assayed by theGe ')'-ray spectrometry. The details of experiments aredescribed elsewhere. 1)
From the results, the mean projectile recoil ranges(FW) are obtained, where F is the fraction of the radioactivity collected in the forward foil and W is thetarget thickness in mg/cm 2 . Then we deduced recoil
velocities of product nuclei and the linear momentum
transferred (LMT) from the projectile to the target nucleus using the range-energy table calculated with the
OSCAR code. 2 )As an example, the LMT at a bombarding energy of
38 MeV/nucleon as a function of the product mass isshown in Fig. 1. The LMT takes the maximum value
around A = 100 to 110, and this mass region corresponds to the peak position of the mass distribution
originated from the incomplete fusion. From the results, the average LMT values were deduced at various
bombarding energies. As the beam energy increases,
the average LMT decreases almost linearly.

ELAS =1.52GeV

o
o
o
A

Fig. 1. The longitudinal momentum along beam direction at the bombarding energy of 38 MeV/nucleon as afunction of the product mass number.

it

Regardless of the target-projectile combination,
was reported that the LMT obeys Leray's

100

p= 1
P= -1.904Vrel + 1.19

for
for

Vrel 2: 0.1
Vrel:::; 0.1

wherev.rei -- J2(Ecm - Vo) .
M

The averaged LMT values as a function of Vrel areplotted in Fig. 2 as ratios to those on the assumptionof full momentum transfer. There is a discrepancy between the systematics and the observed values. The
data from Refs. 4 ,5) are also plotted in the same figure. The figure demonstrates that the projectile dependence is more remarkable than the target dependence.

1\

E-<

~v 0.5

o

•
•

•

•
0.4

Fig. 2. Comparison of the average LMT with the Leray systematics. The symbols represent the projectile-target
combinations: (e) 12C + natCu,4) (0) 40 Ar + 141Pr,
and (..6.) 40 Ar + natcu.5)

4OAr+ 141Prosystematics: 3)

The LMT is very useful to help us in understanding
the incomplete fusion mechanism. But the systematics taking the dependence on both projectile and target
into consideration would further refine our understanding of the incomplete fusion mechanism.
References
1) K. Takesako et al.: OULNS Ann. Rept., p. 122 (1992).
2) K. Rata and H. Baba: INDC(NDS)-195-GZ, p. 131(1981); JAERI-M, p. 88 (1988).
3) S. Leray: J. Phys., C4, 275 (1986).
4) J. P. Whitfield and N. T . Porile: Phys. Rev., C47, 1636
(1993).
5) E. Taniguchi et al.: Radiochim. Acta, 62, 163 (1993).

RIKEN Accel. Prog. Rep. 28 (1995)

Y. Ohkubo, Y. Kobayashi, S. Ambe, K. Harasawa, T. Okada, F. Ambe, K. Asai, and S. Shibata
Using TDPAC and Mossbauer techniques, we measured the hyperfine fields at 99Ru in YBa2Cu306.8 and
YBa2Cu306' We have then found that the parent nuclide 99Rh exclusively occupies the Cu-1 site of bothoxides and that there are two and one types of oxygen coordination around 99Ru in YBa2Cu306.8 and
YBa2Cu306, respectively, corresponding to the observed electric field gradients (EFG 's). 1) In this report,
we describe our conclusion on the oxygen coordination.
The EFG at 99Ru is produced by the valence andclosed-shell electrons of the probe atom; the surrounding oxygen ions distort the spherically symmetric distribution of the closed-shell electrons of the probe atomand then contribute to the EFG. In order to determine the oxygen coordination around 99Ru, we referto the results of a point charge lattice sum calculation for (FeOn)-m in YBa2Cu307-0.2) This calculation
deals only with the closed-shell electron contribution
and is thus not considered to give accurate values ofthe largest principal axis component of the EFG, Vzz .
However, from the combined studies of EXAFS and
Mossbauer spectroscopy on YBa2(Cul-xFexh06.9, we
consider that the calculation reproduces the relative
magnitudes of Vzz at 57Fe with respect to the oxygen
coordination, indicating that the magnitude of EFG
due to the valence electrons correlates to that due tothe closed-shell electrons; this is because the neighboring ions certainly influence the distribution of thevalence electrons of the probe atom through the chemical bonding. We note that 57Fe occupies the Cu-1
site of YBa2Cu307-o and is considered to take approximately the same valence of +4 irrespective of 8, andthat 99Ru in the same matrix is constantly tetravalent.
Therefore, we may apply the lattice sum calculational
results for 57Fe to the case of 99Ru.
The calculation for 57Fe in YBa2Cu307-o immediately leads to the assignments for 99Ru in
YBa2Cu306.8 and YBa2Cu306 shown in Table 1. Using a notation of Vzz (99Ru-4), for example, for Vzz at
99Ru with the 4-fold oxygen coordination, we noticethat VzA 99 Ru-4) and Vzz (99Ru-3) are essentially equal
to VzA 57 Fe-4) and Vzz (57Fe_3), respectively, whileIVzzl = 0.7 x 1022 V 1m2 at 99Ru in YBa2Cu306.8
is about two times smaller than Vzz (57 Fe-5), fromwhich we assign IVzzl = 0.7 x 10 22 V 1m2 at 99Ru in
YBa2Cu306.8 to the 6-fold oxygen coordination.
In Fig. 1 are plotted the VzAT)IVzAO) at 99Ruin YBa2Cu306.8 and in YBa2Cu306 versus T 3 / 2 ,together with those at 57Fe in YBa2(Cul-xFexh07(dashed line: IVzzl~1.3 x 10 22 V 1m 2 at 293 K).4) The
solid lines are least-squares ones fitted to our data. In
the temperature range we studied, the Vzz's at 99Ru
roughly follow the empirical expression obtained for
noncubic metals, Vzz(T)IVzz(O) = [1 - ,8T3 / 2 ]; thermal motions of the lattice ions average EFG, reducing
Vzz with increasing temperature. The coefficient ,8 is
proportional to (M8b)-1, where M and aD are themass of the vibrating ions and the Debye temperature. From the obtained ,8 values, we conclude thatthe thermal motion of the heavier probe atom is more
effective than that of the lighter oxygen in averaging
EFG at high temperatures and that as the coordination number increases, more restrictions are imposedon the motion of 99Ru, making the ,8 value smaller.
This conclusion on the behavior of the {3 value is reasonable and supports our assignment of the oxygen
coordination around 99Ru.

Table 1. Vzz's for various local oxygen configurations
around 57Fe and 99Ru at room temperature.

2) C. W. Kimball, J. L. Matykiewicz, H. Lee, J.
Giapintzakis, A. E. Dwight, B. D. Dunlap, J. D. Jorgensen, B. W. Veal, and F. Y. Fradin: Physica C, 156,

T (K)

1.3

0

500
•
"
•

1.2

Q

900

1.1

Ru (4)Ru (3)Ru (6)--- Fe(5)2- 1.0

~ 0.9

E 0.8

~ 0.7 .
0.6
0.5

0

1

2

3

T3/2 (l04K3/2)

Fig.
1.
Temperature dependence of Vzz at 99Ruin YBa2Cu 3 06.8 and YBa2Cu3 06 together withthat at 57Fe in YBa2{Cul-xFex)307 (dashed line:
IVzzl~1.3 x 1022 V 1m2 at 293 K).4)
References
1) Y. Ohkubo, Y. Kobayashi, K. Harasawa, S. Ambe, T.
Okada, K. Asai, S. Shibata, M. Takeda, and F. Ambe:
Hyperfine Interact., 84, 83 (1994).

Coordination Vu at 57Fe (calc.)a) IV.. I at 57Fe (obs.)b) IV.. I at 99 Ru (obs.)c)number(10 22 V 1m2)
(10 22 V 1m2)
(10 22 V 1m2)
2
-2.9
3
-2.2
1.62
1.7
4
2.2
2.36
2.3
5
1.2
1.27
6
0.4
0.7
a) Point charge lattice sum calculatiolUl by Kimball et al. (Ref. 2).
b) Reference 3. c) This work.

547 (1988).

3) M. G. Smith, R. D. Taylor, and H. Oesterreicher: Phys.
Rev., B42, 4202 (1990).

4) E. B. Saitovitch, R. B. Scorzelli, I. S. Azevedo, and H.
Micklitz: ibid., B41, 2103 (1990).

101

RIKEN Accel. Prog. Rep. 28 (1995)

A New Set-up for In-Beam Mossbauer Spectroscopy at RARF
Y. Yoshida, Y. Kobayashi, K. Yukihira,* K. Hayakawa,* H. HaBlein, S. Nasu, and F. Ambe
Short-lived nuclei beams produced by Coulomb excitation and other nuclear reactions such as 56Fe(d,p )57Fe are opening a new field in materials science l - 5):(1) Single isolated atoms can be observed in any hostmatrix with no restriction of the solubility of the probe
atoms.
(2) In an in-beam Mossbauer experiment, theMossbauer ,-rays are detected within the lifetime of
the Mossbauer excited state (7' = 140 ns for 57Fe) after
implantation of every excited probe nucleus. This provides not only a unique measuring-time-range of about
100 ns for solid state physics and chemistry, but also
atomistic information on electronic states and lattice
vibrations at different lattice sites.
(3) Atomic jump processes on substitutional and/orinterstitial sites can be followed even in inert gas solids
at different temperatures. A study on the jump processes of Fe atoms in solid Ar is in progress using a
new in-beam system at RARF described below.
(4) Since the time-bunched-pulsed heavy-ions beam
is employed in the experiment, it is also possible tostudy dynamic effects just after the implantation bymeasuring spectra with different time windows.
Recently, we have completed a new set-up for the
in-beam Mossbauer spectroscopy at the E7C beamline connected with AVF cyclotron,6) as shown in Fig.
1. This system consists of three parts; main chamber,sample preparation room, and vacuum chambers witha Faraday-cup. Using a DOS/V-PC machine locatedin the measurement room, we can monitor and control
the whole measuring system; all experimental parameters such as the temperature and the position of specimens, the degree of vacuum in the whole chamber, andthe manipulation of pumping systems and all vacuum
valves. The ,-rays from the 14.4 keV Mossbauer levelof 57Fe are detected by two parallel-plate avalanche
counters (PPAC) which are filled with acetone gas of
25 mbar. The fast timing signals from the PPACs areamplified and used for the ,-ray counting. The data
are collected and processed by the same computer.
In our first beam time, we used 40 Arll+ ions witha total energy of 100 MeV for Coulomb excitationof 57Fe. The performance of the in-beam Mossbauer

Shizuoka Institute of Science and Technology

102

Cryostat + SAM.~PL=E:;::::;::J

Fig. 1. The in-beam Mossbauer system located at thebeam-line in E7 experimental hall.

spectrometers and the on-line operations of all other
instruments were checked and confirmed. However,both the time structure and the intensity of the pulsed
Ar beam available at the time were still far below ourdemand. Further developments on the beam structure
and the intensity at AVF cyclotron are highly desirable to achieve an in-beam Mossbauer experiment. In
order to get higher S/N we have been developing new
PPACs using FeTi and FeAI evaporated films.

References
1) M. Menningen, R. Sielemann, G. Vogl, Y. Yoshida, K.
Bonde-Nielsen, and G. Weyer: Europhys. Lett., 3, 927(1987).
2) Y. Yoshida, M. Menningen, R. Sielemann, G. Vogl, G.
Weyer, and K. Schroeder: Phys. Rev. Lett., 61, 195(1989).
3) Y. Yoshida: Hyperfine Interact., 47, 95 (1989).
4) R. Sielemann and Y. Yoshida: ibid., 68, 119 (1991).
5) P. Schwalbach, S. Laubach, M. Hartick, E. Kankeleit,
B. Keck, M. Menningen, and R. Sielemann: Phys. Rev.
Lett., 64, 1274 (1990).
6) Y. Kobayashi, Y. Yoshida, H. HaBlein, S. Nasu, and F.
Ambe: RIKEN Accel. Prog. Rep., 27, 111 (1993).

RIKEN Accel. Prog. Rep. 28 (1995)

Extraction of Intense Slow Positron Beam from Various Targets
Irradiated with p+ and d+ Ions
Y. Itoh, K. Lee, I. Kanazawa, N. Oshima, T. Nakajyo, A. Goto, N. Nakanishi, M. Kase, and Y. Ito
The production of int ense slow positron beams (>108 e+ /sec) is motivated by the prospect of its broad
applications. For the past decades most positron studies have been performed using 22N a of {3+ -decay radioisotope because of its long life time (2.67 yr.) andproper intensity. The maximum intensity of the slow
positrons from commercially available 22Na is less than
106 e+ /sec with moderation efficiency of ~10-4.1)
More intense slow positron beam (more than ~108
e+ /sec) is needed to develop applications such as apositron reemission microscope (PRM), low energy
positron diffraction (LEPD) etc. from their present
preliminary stage to practical performance. For thelast several years LINAC has been used 2,3) to obtainhigh intensity slow positrons of 2:: 107 e+ /sec by pair
production. However the slow positron beam from
LINAC has a pulsed structure and thus it must be
given a further beam processing, and moreover the system is expensive and of a large non-laboratory scale.
On the other hand, production of {3+ -decay radioisotopes using a cyclotron has several advantages. A
high intensity direct current (DC) slow positron beam(~108 ,....., 10 9 e+ /sec) is directly obtained from a relatively inexpensive compact system.
Using the RIKEN AVF cyclotron, various targets
were irradiated with a proton or deuteron beam to produce {3+ -decay radioisotopes. Using a well annealed W
film (with a thickness of 10 /.Lm) as a moderator, slow
positrons were extracted at 30° backward to the incident ion beam. This geometry was chosen to allowfor (1) extraction of the slow positrons during the ion
beam irradiation and (2) the use of various kinds oftarget materials. We produced {3+ -decay radioisotopes
from various targets such as boron nitride (BN), aluminum (AI) , carbon (C) , and silicon nitride (Si3N4)
using a proton or deuteron beam from the RIKENAVF Cyclotron. The reactions that lead to the formation of the {3+ -decay radioisotopes are 11 B(p,n)l1C and
14N(p,a)l1C for BN, 27 AI(p,n) 27 Si for AI, 12C(d,n)13N
for carbon, 28Si(d,n)29p and 14N(d,n)150 for Si3N4.
Table 1 summarizes the slow positron counts emitted
from each target at different beam energies and threedifferent geometries of the moderator for BN and Al
targets. The intensity of the slow positron beam isstrongly dependent on the target materials, energy of
the ion beam, condition of the moderator and geometry of the target holder. In the current stage we obtained 5.6 x 104 e+ /sec per 4 /.LA of proton beam froma boron nitride target. We expect slow positron countsof> 106 - 7 e+ /sec with proper selection of a target andenergy of irradiation ion beam, target geometry andgood condition of the moderator. From the preliminary experiments we conclude that the condition of
the moderator is one of the major factors for the emission of slow positrons. Therefore, in the future experiments a newly designed chamber equipped with an
in-situ moderator annealing system will be used to obtain a better condition of the moderator. The numberof the slow positrons was determined in a gated beam
operation mode, where the ion beam irradiation was
switched on and off at short intervals (typically 1 sec)
and the coincidence counts of the annihilation ,-ray
were measured while the beam was off. The signal tonoise ratio drastically increased by 3 orders of magnitude in this method. This implies that a short lengthof beam guiding line as in the previous system will not
become an obstacle to perform actual experiment if thegated beam operation is applied.
Table 1. Measured slow positron counts from each target
irradiated with different ion beam energies and different
types of moderator and conditions.
Proton b eam
E nergy of Targe
p+ b eam

7MeV

10 Me V
14 Me VC urre nt ofp+ b eam

BN
BN
BN
Al
BN
Al

4 pA
5 pA
4-4 /JA
4-4/J A
3 .6/J A
3 .6 pA

BN
BN

4 ,0/JA
4 ,0 pAe+ cou nts
Type of
Expected e+measured at theModerator
counts at max
operated pA(Condition)
current (20 /JA)
1.3 X 104 e+ /sec
Model-1
6,5 X 104 e+ /sec
8,5 X 102 e+ /sec Model-2 (Used) 3-4 X 103 e+ /sec
4 ,5 x 10 3 e+ /sec Model-3 (New) 2,0 X 10 4 e+ /secoModel-2 (Used)01.02 X 104 e+ /sec Mo d el-3 (Used) 5.7 X 10 4 e+ /sec
2
5 ,5 X 10 e + /sec Model- 2 (Used) 3 . 1 X 103 e+ /sec
7 .8 X 10 3 e+ /sec l\Iodel- 2 (Used) 3 .9 X 104 e+ /sec
5 ,6 X 10 4 e + /sec Model- 2 (Ne w) 2.8 X 105 e+ /sec

D e ut eron b eam
E nergy of Targed + b eam

8 Me V

Carb onSi3 N 4

C urre nt ofd+ be am
1 3 pA
1.3/J Ae+ count s
Type of
Expected e+m easured at theModerator
counts at max
oper a t e d /JA(Condi t ion)current (10 /JA)
4 .2 X 10 3 e + /sec Model- 2 (New) 3 ,2 X 104 e + /sec
3 .4 X 103 e + /sec
Mode l-2
2 .6 X 104 e+ /sec

References
1) E. Gramsch, J . Throwe, and K. G. Lynn: Appl. Phys.
Lett., 51 , 1862 (1987).
2) L. D. Hulett, T. A. Lewis, D . L. Donohue, and S.
Proc. 8th Int. Conf. on Positron AnnihiPendyals:
lation, Gent, p. 586 (1989).
3) Y . Ito, M. Hirose, S. Takamura, O. Sueoka, 1. Kanazawa,
K. Mashiko, A. Ichimiya, Y. Murata, S. Okada, M.
Hasegawa, and T. Hyodo: Nucl. Instrum. Methods
Phys. Res., A305, 269 (1991).

103

RIKEN Accel. Prog. Rep. 28 (1995)

Positronium Formation and Annihilation in Porous Silicon
Y. Itoh, H. Murakami, and A. Kinoshita*
We have previously reported the existence of a long
lived positronium in a porous silicon made by annodization of a silicon crystal. l - 3 ) It has been foundthat the annihilation rate of a positronium is temperature dependent. The effects of gas atmosphere andtemperature dependence on positronium annihilationin porous silicon have been examined in this experiment. The longest component is shorter in oxygen
atmosphere than those in vacuum and in nitrogen because of the ortho-para conversion process in the oxygen condition.
Table 1 shows the lifetime and S-parameter of thethree components in porous silicon, measured in oxygen, nitrogen, air, and vacuum. The oxygen gas
Table 1. Lifetime and S-parameter of porous silicon indifferent gas conditions.
Atmosphere

S-parameter
71 (II)
72(h)
73(h)
ps(%)
ps(%)
ps(%)
0.491
201 (48) 356 (36) 36000 (16)

In Nitrogen(1 atm)In Vacuum 234 (68) 472 (11) 35900 (21)(8 x 1O- 9 Pa)
In Air237 (69) 556 (9) 22000 (22)
(1 atm)In Oxygen
264 (77) 654 (8) 10200 (15)
(1 atm)

0.517
0.603
0.628

Department of Science and Engineering, Tokyo Denki
University

104

caused a drastic decrease in the longest lifetime. Most
molecules of oxygen are absorbed in the pore space,or on its surface. The amount of oxygen dissolved additionally into the bulk layer at 300 K is thought tobe negligible compared with that in the pores. We
consider that the ortho-positronium with lifetime 73 is
free in the pore and collides with the pore surface andthe introduced gas molecules, since 73 changes throughoxygen exposure. The shortened lifetime in an oxygen
atmosphere is reasonably understood in terms of thespin conversion of ortho-positronium, following the interaction with oxygen molecules in the pores or on thepore surface. Nitrogen had no effect on the ortho-paraconversion. We are progressing the experiments on thetemperature dependence positron/positronium annihilation under a designated gas atmosphere such as oxygen, nitrogen and the others. Positron annihilation
spectroscopy will be a tool to make the surface stateof porous silicon and elucidate the photoluminescencemechanism.
References
1) Y. Itoh, H. Murakami, and A. Kinoshita: J. de Phys.,IV, 3, 193 (1993).
2) Y. Itoh, H. Murakami, and A. Kinoshita: Appl. Phys.
Lett., 63, 2798 (1993).
3) Y. Itoh, H. Murakami, and A. Kinoshita: RIKEN Accel.
Prog. Rep., 27, 92 (1993).

4. Radiation Chemistry and Radiation Biology

RIKEN Accel. Prog. Rep. 28 (1995)

Time and Depth Resolved Dynamics of Excited States
in Ion Track in Condensed Matter
K. Kimura, T. Yoshikane, and H. Kumagai
1) Dynamics of core and self-trapped excitons produced in ion irradiated BaF 2 and CsCl.
Recently, above crystals are of interest not only as
new scintillators for high energy physics but also as
crystals presenting new exciton luminescence. Studies on luminescence mechanisms and exciton dynamics have been carried out using synchrotron radiationand energetic electron. The new luminescence bandat 220 nm was assigned to transitions of valence electrons to the hole of the outermost inner shell andnamed the Auger-electron-free luminescence (AEFL).
Another luminescence band at 310 nm was assigned
due to the self trapped exciton (STE) similar to those
for alkali halide crystals. We have studied on dynamical effects of ion-irradiation of the exciton luminescence, with development of techniques for fast luminescence decay measurements (SISP) of 100 ps resolution, using incident ions of comparatively low energies of about 2.0 MeV/nucleon. Some of new findings for BaF 2 have been reported already: excitationdensity dependent shortening of the lifetime of AEFL
and its mechanism 1 ) ; similar shortening for STE, but
a different mechanism i.e. the STE-STE exchangeinteraction.2) In this report , further new findings andresults on a CsCI crystal are mentioned briefly. Kinetics on AEFL of ion-irradiated BaF 2 enabled us toestimate the formation efficiency of the core hole Ba3 + .
Figure 1 shows the efficiency per a nucleon as a function of LET (linear energy transfer) of various projectiles. There appeared a minimum evidently at LET
due to N-ion. This may be explained by a mechanismthat the core hole is formed by the Fano-type charge
exchange process, namely, the transient pseudo molecular orbital formation between a projectile and a Ba2+;
the efficiency of the MO formation is the lowest in caseof N-ion. A new finding for STE of BaF2 is on unusual
temperature effect on the luminescence decay. Figure
2 shows that with decreasing temperature the decay
times are shortened from several ns to about 400 ps
with no prominent change in the intensity. This temperature effect is reverse to results for photoirradiation
by synchrotron radiation that the decay time of about
1 J.ls at room temperature is lengthened to about 10
J.ls at 50 K. The results may suggest that the STE isformed much densely with decreasing temperature because of decreasing rate of hole migration, resulting in
an increase in the exchange interaction. This situation
seems to induce the stimulated luminescence.
Ion induced AEFL of a CsCI crystal also showed solarge excitation-density effect that the decay time at
the initial stage was 150 ps at room temperature in

OJ

:g
~
o

6

u

o
H~

10
N

Ar

Kr

LETlMeVcm'mg ol

Fig. 1. Formation efficiency of the core hole Ba3 + per a
nucleon as a function of LET.

Fig. 2. Temperature dependence of the decay of STE in
2.0 MeV/nucleon He-ion irradiated BaF 2 •contrast with 880 ps for VUV irradiation. However,the decay time was increased considerably with decreasing temperature although the dependence in caseof BaF 2 was scarce. On the other hand, ion-induced
STE of CsCI presented very short decay constants,
which were nearly independent of temperature. These
results may be explained by substansially the samemodels as which succeeded in the case of BaF 2, but
detailed analyses are going on.
2) 'frack-depth resolved dynamics of excited states.
Bragg-type curves were measured successfully for
excited states produced in a dense Ar gas presessurized closely at the critical temperature, which is anextended study of preveous one on dense He. 3 ) The
measurements are to be carded out systematically using various projectiles and rare gases to elucidate thebasic track effect as a space of high-density excitation.
References
1) K. Kimura and J. Wada: Phys. Rev., B48, 15535 (1993).
2) K. Kimura: Nucl. Instrum. Methods Phys. Res., B90,
100 (1993); K . Kimura and H. Kumagai: Radiat. Eff.
Def. Solids, 126, 45 (1993).
3) K. Kimura: Phys. Rev., A47, 327 (1993).

105

RIKEN Accel. Prog. Rep. 28 (1995)

Measurements of Heavy Ion Beam Qualities
N. Matsufuji, T. Kanai, H. Tomura, T. Kohno, A. Fukumura, F. Soga, and K. Kawachi
When shaping the range of heavy ion therapy beamat HIMAC, incident nuclides are broken into some fragmented particles by the bombardments with rangeshifter made of lucite plates. It is important to know
about the quality of the beam such as the composition of the beam and/or the contribution of eachfragmented nuclide to LETs to make our treatmentplanning more precise. For this purpose, fragmented
partiCles were measured for the beams of carbon 135
MeV /nucleon and neon 135 MeV/nucleon with changing the thickness of lucite variously.
Figure 1 shows a schematic diagram of a detector system. The system was based on the countertelescope method. A beam monitor made of a plastic
scintillator was located at the most upstream position
to count the number of incident particles. A coincidence detector was composed of a plastic scintillatorof 5.0 mm in diameter and positioned at the downstream of the lucite target to distinguish fragmented
particles from noises. A proportional counter and a silicon semiconductor detector were used as ~E counters
to measure the energy loss ~E in the detectors. At theend of the beam line, a BGO scintillator was utilized
as an E counter to measure total energy E. The BGO
crystal had a cylindrical form, 15.0 mm in diameterand 15.0 mm in length. The measurements were carried out in E5 experimental room of the RIKEN Ring
Cyclotron accelerator facility.

W<l~ ~".'~~. ,..
>- . '. ,W.'.-.,

Z,,3 Z,,4:::.::'~ . •~. < , ., ':: ';~"~• . .

Total Energy E (arbitrary unit)

Fig. 2. The scatter plot of the total energy E andthe energy loss ~E for the incidence of carbon 135
MeV/nucleon beam.

-Calcz=6--·Calcz=5-Calcz=4-Calcz=3- - · Calc z=2········· Calc z=1

o Exp z=6
• Exp z=5o Exp z=4
Exp z=3" Exp z=2.. Exp z=1

Z=6

u

Q)

.~

"iii
E

a

z

Thickness of Lucite (mm)Fig. 3. Fluence spectra of fragments emitted by the incidence of carbon 135 MeV/nucleon beam.

Macroscopic reaction cross sections ~ were deduced
from the fluence of incident nuclide. The ~ is expressedas an exponent of the following equation:
~E

E

N

No = exp( -~x),Fig. 1. The schematic diagram of the detector system.

Figure 2 illustrates an example of E-~E scatter plots
for the incidence of carbon beam with target thicknessof 28.97 mm in water-equivalence. The abscissa represents the total energy E measured by BGO detector
and the ordinate denotes the energy loss ~E from the
Si semiconductor detector. Fragmented particles were
well discriminated by the difference of the kind of nuclide.
Fluence spectra of each nuclide were derived by normalizing the number of particles included in each beltof E-~E scatter plots by the number of incident particles. Figure 3 displays the fluence of each nuclide forthe incidence of carbon beam. The values calculated
by Sihver and Kanai are also plotted for the sake ofcomparison.
106

where x is the thickness of the target, No is the numberof incident particles and N is the number of survived
incident particles. Results are summarized in Table 1.
Table 1. Macroscopic reaction cross sections with a lucitetarget (m - 1) .
Beam
C 135 MeV/nucleon
Ne 135 MeV/nucleon

Experiment
6.71
8.52

Calculation
5.14
7.06

These results indicate that incident heavy ion particles are more disintegrative comparing with calculated
expectations. Precise analyses for the reason of thistendency and other beam qualities such as LET spectra for each nuclide are now in progress.

RIKEN Accel. Prog. Rep. 28 (1995)

The Profile of Chemical Damages in Polymers Induced by
Heavy-ion Irradiation
Y. Hama, K. Hamanaka, H. Matsumoto, and F. Yatagai
The relationship between the energy transfer profile of heavy ion and the profile of chemical structuralchange in polymeric materials has not yet been clear
enough. This may be important in the study on biological effects of heavy ions. The present study isconcerning the depth profile of the chemical damages
in polyethylene irradiated by 135 MeV/nucleon C 6+
from RIKEN Ring Cyclotron.
The sa:f.llples used in this work were low density
polyethylene (LDPE) and high density polyethylene(HDPE). They were formed in a slab of 2 mm thickby heat press. On irradiation, an enough number ofslabs were piled up so that the thickness of the wholesamples was longer than the range of the heavy ion.
Irradiation was carried out in air at room temperature with C6+ of 135 MeV/nucleon.
The sample irradiated was sliced along the crosssection to get a thin film of a few hundreds of p,m forthe micro-FT-IR measurement. We could obtain thedepth profile of chemical changes in heavy-ion irradiated LDPE and HDPE with a micro-FT-IR apparatus
with which it is possible to detect the IR spectrum ina minimum area of 10 p,m x 10 p,m.
The predominant species produced by heavy-ion irradiation were carbonyl group, trans-type double bondand hydroxy group. Figure 1 shows the depth profile
of carbonyl groups and trans double bonds producedin HDPE. The carbonyl groups show very strange absorption in the vicinity of both surfaces of each slab
compared with the inner region, and the envelope ofyields of the carbonyl groups shows a kind of the Bragg
curve. The depth profile of the trans double bond also
looks like the Bragg curve.
The generation mechanism of the predominant
species could be considered as follows: It has been
known that alkyl radical is the predominant radical
produced in polyethylene by 'Y-irradiation. In addition,
the allyl radical is produced slightly. In our previous
study, it has been found that most of oxidation takes
place in the vicinity of the surface when the slab of
PE was irradiated in air bY'Y-ray. It has been considered from this result that most alkyl radicals produced
by 'Y-irradiation disappear by the reaction with oxygen molecules to create carbonyl groups in the vicinity35~---------------------------------'-o-964cm -, (Trans double bond)30-[}-1712cm -, (Carbonyl group)

M~25
'0

x

1:'20
o

~

(; 15

VI

.D

«10

o

10

20

30

40

Oepth(mm)Fig. 1. The depth profile of the IR absorption due tocarbonyl group and trans double bond for HDPE irradiated by 135 MeV /nudeon C 6 + in air at room temperature.

of the surface and that they disappear by recombination to create cross links in inner region. On the other
hand, allyl radicals disappear by the reaction with oxygen molecules , although they are stable in vacuum atroom temperature.
It may be considered that a reaction similar to theone on 'Y-irradiation takes place also on heavy-ion irradiation. That is, a large number of carbonyl groups
observed in the vicinity of surface in each slab is considered to come from the reaction of alkyl radicals withoxygen molecules, though slight oxidation due to allyl
radicals occurs. Moreover, alkyl radicals are considered to disappear by the recombination before they react with oxygen molecules which diffuse into the inner
region. Therefore, the carbonyl groups produced in the
inner region in each slab come from the oxidation ofallyl radicals. This consideration leads to a conclusionthat the relative yield of allyl radical to alkyl radical
should be larger than that on 'Y-irradiation. This is
supported by the fact that the G value for production of trans-double bonds also is larger than that on'Y-irradiation. These results suggest that the chemical
reaction processes on heavy-ion irradiation are affectedby ionization or excitation in high density which is due
to high LET.

107

RIKEN Accel. Prog. Rep. 28 (1995)

Radiation Effects of Ion-particles on Various DNA Structures (2)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. Due to the technical limitation in analyzing thechange of molecular structure oflong DNA, the biological effects of radiation have been studied mostly on thestrand breakage of DNA whose molecular weights areless than 108 (I"'V 1. 5 x 105 base pairs).
Recent technichal progress in the analysis of large
DNA such as pulse field gel electrophoresis (PFGE)
makes it possible to measure the molecular change oflong DNA bigger than 1"'V107 base pairs.
Even though a prokaryotic cell has no nucleus its
single molecule of double-stranded DNA, corresponding to one chromosome, is folded extensively withina small cell envelope. Many cellular constituents arethought 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 orenhance the radiation damages on it. Following thestudies reported last year (1), we continued such experiments to confirm the differrent radiation effecs on"naked", "folded" or "packaged" DNA. In order to prevent free diffusion of such DNA, cells were solidified
with agarose and treated with or without lysozyme,
RNase and/or proteinase. We confirmed by electronmicroscopic observation that DNA, after removals of
RN A and proteins, is still enveloped in an agarose holewhose diameter is almost the same as that of intact
cells (data not shown). Therefore, it can be thoughtthat even in the "naked" sample DNA is still folded ina small space corresponding to the single cell. Therefore, the name of a "folded" sample must be changed
to a "cell wall and RNA free" sample as a more appropriate terminology.
In order to compare the radiation effects of N-ions(",135 MeV/j.£, data presented last year 1)) , Ar-ions(1"'V95 MeV/j.£, Fig. l(a)) and 60Co ,-rays (Fig. l(b))
on these three folded forms of DNA, cells of Deinococcus radiodurans were solidified with agarose (DNA isstill "packaged" in a cell with its constituents). Before
irradiation the cells were lysed with lysozyme in thepresence of RNase ("cell wall & RNA free") followedby proteinase K treatments ("naked"). RNA and proteins were removed by incubation with these enzymes
following the irradiation and DNA was digested witha restriction endonuclease, Not 1. The digested fragments (Not I fragments) were analysed by PFGE as
Japan Atomic Energy Research Institute108~irection of electrophoresis(a)1 2 3 4 5 6 7 8 910

nut {!!
,;jt!L Hi

TEl& H,:ud UNi( , --

~

•

.,\
Ii
.,,,,

~

A -ladder DNA -arker

o Gy
100

Gy "packaged"

200

Gy

300

Gy

500

Gy

100

Gy "c ell wall

200

Gy

300

Gy

500

Gy

100

Gy "naked"

200

Gy

300

Gy

500

Gy

a RNA free"(b)
A - ladder DNA nrker

o Gy
500

_

~,

~

Gy

750

Gy

1000

Gy

500

Gy " cel l wall

600

Gy

150

Gy

.
". ,

~

.a*i'

I
I

Gy "packaged"

600

1000

Gy

500

Gy "naked"

600

Gy

150

Gy

1000

Gy

a RNA free"Fig. 1. Disappearance of Not I fragments in three different folded forms of DNA after the irradiation with
Ar+ -ions(a) and ,-rays(b). Molecular weights of the'x-ladder DNA size standard shown in the figure are as
follows(bp): 1 = 48.5 k, 2 = 97.0 k, 3 = 145.5 k, 4 =194.0 k, 5 = 242.5 k, 6 = 291 k, 7 = 339.5 k, 8 = 388.0
k, 9 = 436.5 k, 10 = 485.0 k.

shown in Fig. 1.
Several conclusions can be drawn from the figure; (1)Among the three folded forms of DNA the most sensitive to these radiations is that which is in a "cell walland RNA free" sample. (2) Irradiation with the ionsdisrupt Not I fragments more efficiently than ,-rays.
(3) Among the Not I fragments the biggest fragment(ca 480 kbp) is more sensitive to radiations than theothers (400, 390, 360,324,255,240, 225,215, 109,102,
100 kbp). After completing more detailed experiments
these results will be analyzed quantitatively using densitometer tracing.
References
1) S. Kitayama et al.: RIKEN Accel. Prog. Rep., 27, 100(1993).

RIKEN Accel. Prog. Rep. 28 (1995)

Analysis of Mutations in the Human HPRT Gene Induced byAccelerated Heavy-ion Irradiations
Y. Kagawa,* F. Yatagai, M. Suzuki, Y. Kase, A. Kobayashi,* M. Watanabe, and F. Hanaoka
A knowledge of the specificity of mutation induced
by a variety of mutagens has proved useful for better
understanding of the molecular mechanisms of mutagenesis. In the past decade, a vast amount of data
has been generated concerning cell death, mutation,
chromosomal aberreation etc. by means of accelerated
heavy-ions. Suzuki et al. l ) have already reported hypoxanthine phosphoribosyltransferase (HPRT) mutations obtained from the carbon-ion irradiation of human embryo cells. The initial energy of C-ion 135
MeV In was degraded to adjust the linear energy transfer (LET) to 39, 68, 124, or 230 ke V Imm when the cells
were irradiated.
In this report, we investigated DNA sequence alterations in HPRT cDNA of mutant clones recovered from. 230 keY I J.Lm carbon-ion irradiations. The genomic
DNA of these mutants have already been shown torepresent normal electrophoretograms when they areamplified by multiplex PCR.
We extracted mRNA and genomic DNA from 6thioguanine (6-TG) resistant mutants by a proceduredescribed previously. 1) After reverse-transcriptingmRNA to cDNA, the HPRT structural gene was amplified by PCR and sequenced by dideoxy method. Southern hybridization was carried out on EcoRI or PstI digested genomic DNA utilizing an exon6 region (258bp)
as a probe.
Eighteen HPRT cDNAs of mutant clones obtained
from 230 keY Imm carbon-ion irradiation were sequenced. As shown in Table 1, deletions of exon6(83bp, 403-485) were the most frequent mutational
events (10 clones), and the deletion of both exon6
and exon8 (77bp, 533-609) was next most frequent (6 clones), followed by base substitutions (2clones: 415 ACT -+ GCT, Thr -+ Ala, 7 ACC -+Table 1. Comparison of mutational events.
Class of mutation
Base substitution
Frame shift (base addition)
Deletionexon6exons 6 and 8
exons 2 and 3
unidentified (point mutation)
Total

Incidence
C-ion (230 keY / J1-m) Spontaneous
2 (11%)
5 (50%)
2 (20%)o
16 (89%)2 (20%)
10
o
o
6

o

2

18 (100%)

1 (10%)
10 (100%)oATC, Thr -+ Ile). For comparison, we also characterized the 10 spontaneous HPRT mutatants by thesame methods. In contrast, the most frequent mutational events of spontaneous mutants were base substitutions (5 clones) followed by deletions of both exon2
and exon3 (2 clones) and frameshift (2 clone). One remaining clone was unidentified, but this clone did not
represent any deletions of exons.
Because all these mutants have been certified by
the multiplex PCR analysis to have all exons on theirgenome, these deletions were supposed to be due tothe translocation of each exon region or the abnormalmRN A splicing. Analyses of intron regions upstreamexon6 and exon8 by genomic Southern, DNA sequencing and restriction enzyme digestion suggested that theabove deletions induced by 230 keY I J.Lm carbon-ion
were due to the abnormal mRNA splicing. We needto confirm the possibility that these observed characteristics are specific to the effect of a heavy-ion.
References
1) M. Suzuki, M. Watanabe, T. Kanai, Y. Kase, F.
Yatagai, T. Kato, and S. Matsubara: Adv. in SpaceRes., in press.

Toray Research Center Inc.

109

RIKEN Accel. Prog. Rep. 28 (1995)

Induction of Apoptosis in CHO Cells Exposed to
Accelerated Neon Ions
H. Sasaki, F. Yatagai, Y. Furusawa, T. Kanai, and F. Hanaoka
Radiation-induced death of cultured mammaliancells is divided into reproductive and interphase death.
The former is observed among cell progenies during
several generations after exposure to moderate dosesof X rays less than 10 Gy, whereas the dose more than
10 Gy is required for the latter to occurr. Heavily Xirradiated CHO (Chinese hamster ovary) cells stopped
cell progression at the G2 phase and became giant.
Since caffeine has been shown to override G 2 block, we
examined if caffeine could induce these giant cells toenter mitosis. Although they soon rounded up upon
addition of caffeine as if they entered mitosis, they,
when stained, showed nuclear condensation which led
to apoptotic changes including fragmentation of nucleus as well as internucleosomal DNA. Furthermore,
caffeine-induced apoptosis was suppressed by the incubation at the nonpermissive temperature of FT210
cells which have a ts defect in cdc2 HI kinase,1,2) suggesting the CDC2-dependent chromatin condensation
required for nuclear condensation during apoptosis ofheavily irradiated cells destined to undergo interphase
death.
We previously found by means of the time-lapse photography that HeLa cells exposed to a particles from
241 Am underwent interphase death more frequently
than those exposed to X rays at the dose corresponding
to the same survival level. 3) In the present preliminary
study, the dose dependence of apoptosis induction in
CHO cells was compared between X rays and monoenergetic Neon ions at Bragg peak (135 MeV In, LET: 100
KeV I /-L m ) generated by RIKEN Ring Cyclotron. After
exposure to graded doses of X rays or Neon ions, cells
were incubated for 24 h and then treated with caffeine(5 mM) for 2 h. Fraction of induced apoptotic cells wasdetermined by counting round cells with condensed nuclei. The results in the Fig. 1 show that apoptotic

110

60

50

I/)

40

I/)

0

Co
c..

c(
~
0

X·ray + Caffeine
Ne·lon + Caffeine

20

X·ray
Ne-Ion

10

20

40

60

80

100

120

Dose(Gy)

Fig. 1. Dependence of caffeine-induced apoptosis on doseof X ray and Neon ion in eHO cells.

cells increase linearly with dose of Neon ions within therange less than 10 Gy where they are scarecely seen in
X-irradiated cells. High incidence of apoptosis in cells
exposed to relatively low doses of Neon ions may be
due to the formation of locally multiply damaged sites(LMDS) in target molecules (DNA). These facts suggest a predisposition to interphase death of heavy-ion
irradiated cells. Evaluatiop. of dependence of apoptosis induction on dose is now in progress using a more
precise method.
References
1) C. Mineo et al.: Exp. Cell Res., 161, 53 (1986).
2) J. P. H. Th'ng et al.: Cell, 63, 313 (1990).
3) H. Sasaki: Radiat. Res., 99, 311 (1984).

RIKEN Accel. Prog. Rep. 28 (1995)

Biological Effectiveness of Heavy-Ion Beams on
Cultured Mammalian Cells
Y. Furusawa, K. Fukutsu, K. Ando, H. Ohara, F. Yatagai, and T. Kanai
The relative biological effectiveness (RBE) isthought to be given by a simple function of the linear energy transfer (LET) , which is described as alinear-dimensional energy-deposit density. The threedimensional energy-deposit density is different according to the types of accelerated ions when their LETs
are the same, because of the difference in the velocities
and electric charges of the accelerated ions. The crosssections between the ions and energy-absorbing materials, such as living cells, are different based on thetarget sizes of the irradiated cells, the truck structureof the accelerated ions, t he target-truck distance, andso on. Thus, t he biological effectiveness to the same
LET ion beams may vary according to the types ofions and cells. To obt ain the difference among the ion
species as well as among the cell strains, we exposed
V79 cells (from Chinese hamster) and HSG cells (fromhuman salivary grand tumor) to several types of ion
beams having various LETs under both aerobic andhypoxic condit ions.
The cell-killing efficiency of HSG and V79 cells wasmeasured with various LET beams of 3He, 12C, and
20 Ne ions under both aerobic and hypoxic exposure
conditions. For the irradiation of heavy-ion beams,
the medical cyclotron at the National Institute of Radiological Sciences eHe ions and 12C ions at a highLET region) and the RIKEN Ring Cychrotron (12 C
and 20Ne) were used as t he sources of ion beams. Details concerning the irradiation systems were reported
previously. 1) The survival curves of V79 cells for lower
LET beams had large shoulders (3.8 Gy as D q , at 20
keY / /-Lm for aerobic condition) , and that of HSG cells
had small shoulders (1.2 Gy for the 3He-ion and 1.8
Gy for the 12C-ion at 20 keY / J.tm for the aerobic condition); the shoulders were reduced by an incrementof the LET. The survival curves under both aerobic
and hypoxic conditions were analogous for the same
LET beam. The survival-curve parameters were numerically determined by using the Linear Quadratic
Model as a fitting method , rather than the theoreticalmodel of the survival fraction; the DlO (dose required
to reduce the survival to 10%) was obtained for eachexperiment. In this report, the cell survivals are discussed based only on D lO , since it was a stable parameter for our experiments.
Summaries of the DlO values versus the LET for
HSG and V79 cells under both aerobic and hypoxic
conditions are given in Fig. 1; these details were reported previously. 2,3) The DlO values were, for allcases, decreased with an increments of LET to a minimum at about 100-300 ke V / J.tm, and then increased

in a much higher LET region. The LET-DlO curvesof the V79 cells for 3He- , 12C_, and 2oNe-ions wereseparated. Based on the Figs. 1 and 2 in the middle(3D-90 keY / /-Lm) LET region, the lowest DlO at thesame LET radiation was found by the 3He-ion rather
than by other ion-beams. The minimum value of DlO
was, however, not found for the 3He-ion. Because oflimits of the LET range due to the irradiation apparatus, sufficient experiments for finding the minimum
DlO for the 3He ion were not possible. The DlO values were lowest for the 3He ions, middle for the 12C
ions and highest for the 20Ne ions at the same LET in
the lower LET region in the figures. Analogous figures
were found for HSG cells. The LET DlO curves produced by the 3He ion for the HSG cells were lower thanthose produced for the V79 cells by the other ions. In

a

f~f,
o

1

(ij

>

HSG cells
AerobiC0(ij>~ 1g ~O:;-+--+--+-+--j
l 0:0 -;:::~::::':::!±j ' ~

(f)

g

(f)

9

"~~

'----'1V.

V79 cell s
Aero bic

15

01'

0

10

Hy~;;~I1:~
10

100

1000

100
LET (keV/,lm)

LET (keV/!l m)

1000

Fig. 1. Inactivation action spectra for HSG and V79 cells
as represented by a 10% survival dose vs. the LET for
2oNe, 12C, and 3He ion-beams in aerobic and hypoxic ,irradiation conditions.

10

100

1000

LET (keVhlm)

Fig. 2. Difference of the RBE (relative biological effectiveness) between HSG and V79 cells for 2°Ne and 3Heion beams.

111

the curves for HSG cells by the 12C-ion and 2oNe-ions,
it was hard to find any difference between each other.
It is difficult to clear to give a reason for this; it may
be caused by a difference in the target size of these twocell strains and truck structures of the ion beams. Thisdifference due to exposed ions and cell strains is summarized as an expression of the RBE in Fig. 2 by using
some data from the 3He-ion and 2oNe-ion beam experiments. In the figure, not only the difference producedby the ions described above, but a difference due tothe cell strains, could also be found. The RBE curvesof V79 cells for 3He-ions were shifted to a much higher
LET region compared with that of the HSG cells. The

112

same figures could also be found for the 20Ne ions.

References
1) T. Kanai et al. : NIRS-M-91, HIMAC-004; 1, Natl. Inst.
Radiol. Sci., Chiba (1993).
2) Y. F'urusawa et al.: Proe. 2nd Workshop on Phys. BioI.
Res. Heavy Ion., eds. K. Ando and T. Kanai, NIRSM-90, HIMAC-003; 11, Natl. Inst. Radiol. Sci., Chiba(1992).
3) Y. F'urusawa et al.: Proe. 3rd Workshop on Phys. BioI.
Res. Heavy Ion., eds., K. Ando and T. Kanai, NIRSM-90, HIMAC-006; 34, Natl. Inst. Radiol. Sci., Chiba(1993).

RIKEN Accel. Prog. Rep. 28 (1995)

DNA Double Strand Breaks Induced with
135 MeV/nucleon Ne Beam
M. Murakami, K. Eguchi-Kasai, H. Itsukaichi, F. Yatagai, and T. Kanai
Heavy ion particles densely ionize substances thatare just around these tracks. Considering this point,
the biological effect by heavy ion particles may be different from the one by X-ray. We are interested in themechanism of induction of DNA double-strand breaks
on mammalian cells.
For the purpose of analyzing DNA double-strand
break induction by heavy ion particles, the mouse
LTA cells were irradiated with Ne beam accelerated
by RIKEN Ring Cyclotron (the initial energy was 135
MeV /nucleon). After irradiation, cells were counted
and were analyzed by the pulsed-field gel electrophoresis. The pulsed-field gel electrophoresis can separate
the mega-base order large size DNA fragment. Cells
were irradiated with neon beam, and were fixed into
agarose plugs. The plugs were treated by proteinase K
at 50°C for 24 hr. The samples were electrophoresedfor 68 hr at 15°C and 60V with a Hexafield Horizontal
Gel Electrophoresis apparatus with an electrical field
alternating every 30 min. After the electropholesis, thegel was stained with ethidium bromide and visualized.
Double-strand DNA breaks were observed by thepulsed-field gel electrophoresis (Fig. 1). The amount ofDNA double-strand breaks increased as the doses increased. For the DNA repair assay, the irradiated cells
were incubated for 4 hr at 37°C and then the cells weretreated for the sample of pulsed-field gel electrophoresis. The amounts of DNA double strand breaks after 4
hr incubation were decreased. DNA repair was ob-

served in this condition.

Fig. 1. DNA double-strand breaks induced by Ne-beam(LET = 200 keY / p,m) irradiation. M; DNA marker-1.9mega-base-pair (S. cerevisiae) , C; unirradiated control, 10; Ne beam irradiated with lOGy, 30; 30Gy, 60;
60Gy, 80; 80Gy, RlO; 4 hr incubation after irradiation
with lOGy ofNe beam (repair-lOGy), R30; repair-30Gy,
R60; repair-60Gy, R80; repair-80Gy.

113

RIKEN Accel. Prog. Rep. 28 (1995)

Effects of Charged-particle Beams on 11 Mammalian Cell Lines
K. Eguchi-Kasai, M. Murakami, H. Itsukaichi, K. Fukutsu, T. Kanai, Y. Furusawa,
K. Sato,* H. Ohara, and F. Yatagai
It can be noted that it is not simple double strand
breaks (dsb) but non-reparable breaks that are associated with high biological effectiveness in the cell killing
effect for high LET radiation. Here, we have examinedthe effectiveness of low (initial energy = 12 MeV lu)
or high (135 MeV lu) energy charged particles on cell
death in 11 mammalian cell lines including radiosensitive mutants. The dose, required to obtain 10% cellular survival, D lO , was calculated by regression analysis of survival curves according to a linear-quadraticmodel. When DlO doses of charged particles were plotted against those of X-rays, a linear correlation was
obtained (Fig. 1). Fitted lines were calculated by acomputer using linear regression analysis. The slopeof the fitted line has the inverse dimension of relative
biological effectiveness (RBE). This value may relate
to a theoretically maximal value of RBE of each particle beam. The slope varied depending on the radiation quality, generally showing larger values for low
LET He ion and smaller values for high LET C or
Ne ion. This should mean that RBE value is small
for low LET He ion and is large for high LET C or
Ne ion. This is generally observed for the survival ofmany mammalian cells except in a very high LET region. The RBE of particles having LET above 100
keV I /-tm was not necessarily large. RBE values of Mix
beam are smaller than those expected from single irradiation by mono energy particles of the same LET. It
should be noticed that the points of radiosensitive mutants were located in the lower left corner of the figure.
These radiosensitive cell lines were MIa and 8L3-147.
They were deficient in DNA dsb repair and showed
lower RBE values against any particle beam if compared with their parent cell lines. Their RBE values
were very close to unity, independent of the LET or thekinds of particles. On the other hand, human ataxiatelangiectasia fibroblasts, irs 1 and irs 2 cells, that werealso radiosensitive but known as proficient in dsb repair, showed moderate RBE values. These 3 cell lines
showed radioresistant DNA synthesis. Therefore this

Division of Radiation Hazards, National Institute of Radiological Sciences

114

6----- D10forn-<>- He/18.S

5

>;

£!
~
Q)

4

;;

~
c
0

i

3

:s
CD

a::

.e

2

'"
0'"

00

2

3

4

5

6

7

8

0 10 for X-rays (Gy)Fig. 1. Comparison of the cell killing effects among thecharged particles. Dotted line represents the regression
line for neutrons. Cell lines used were MlO, SL3-147,
AT5BIVA, irs1, irs2, L5178Y, HSG, MRC5sv1 TG, R1,
LTA, and V79 (from sensitive to resistant). The numbers following "He" or "C" in the figures were the LETs
in keY / /-Lm. For example, He/75 means the data after
irradiation with He (LET ~ 75 keY / /-Lm). Mix means
two-step-irradiations, 1st with He (12 MeV/nucleon,
about 18 keY / /-Lm) followed byC (12 MeV/nucleon,
about 200 keY / /-Lm) ions.

fact may be an important key to explain the killingof cells by high LET radiation. These experimental
findings suggest that the DNA repair system does notplaya major role against the attack of high LET radiations. Therefore, we hypothesize that a main cause of
the cell death induced by high LET radiations is due
to non-reparable dsb, which are produced at a higher
rate compared with low LET radiations.

RIKEN Accel. Prog. Rep. 28 (1995)

Effects of 135 MeV/nucleon Carbon Ion on Cultured Cells Derived
from Squamous Cell Carcinoma
H. Itsukaichi, H. Ohara, K. Eguchi-Kasai, T. Kanai, K. Sato,* and F. Yatagai
In tumor tissue, there are many clones of cells withdifferent radiation sensitivity against low LET radiations. For cancer therapy by ion beams, it should be
important to predict the sensitivity to charged particles of such cells. We have been examined the radiosensitivity of 19 cell lines against X-ray and somekinds of high LET radiations. R1 cells which arederived from mouse squamous cell carcinoma 1 ) werechosen as one of radio-resistant cell lines. Here, wehave examined the effect of low (initial energy = 12
MeV /nucleon) or high (135 MeV/nucleon) energy ion
beams on the cell death of R1 cells.
Dose survival curves after irradiation with 135
MeV /nucleon C-ion beams are shown in Fig. 1 together with X-ray data. C-ion beams were more effective to kill R1 cells than X-rays as far as tested.
Curves for the LET over 60 ke V / J-Lm have 2 phases,

initial sensitive and second resistant phase. The ratioof resistant population increased with LET up to 167
ke V / J-Lm. This resistant population was not observed
for fast neutrons (data not shown) or X-ray. This may
be due to a technical problem. Studies about this phenomenon are now in progress. Inactivation cross section (a) was calculated from D37 which is the dose
required to obtain 37% cellular survival. D37 was obtained by regression analysis of survival curves according to a linear-quadratic model for the initial slopeof survival curves. a increased with LET up to 200
ke V / J-Lm and looked to be saturated at 400 ke V / J-Lm
(Fig. 2)'. a-LET curve of R1 cells agreed with that of
V79 cells (data not shown).
R1 Celis, Carbon

R1 ICarbon
r--1--.--,-,--r--r--r-M ----e- 3 1.0-+-·59.1' 0 - 100···.··-106.2
t::.

125.9

--&--153- <r - 166.5- X '- X-ray

0 .1

I:

~

~

c:

.2

oCI.I

(f)

(//

~ 10 '

02
U
LL

"'e

(j
c:

0.Q1

o

:;
.~
o

C)

I:
os;
os; 0 .001

(11

.E

~

::::s

en

0.0001

LET (keV//lm)

0.00001 L....-l--l.---I.........I..................I..-...I...-.L..-I----L---I........I
024
8
10
12

Dose (Gy)Fig. 1. Dose-survival curves of R1 cells. The numbers
following symbols in the figure were the LETs of C-ion
beams in ke V / /-Lm.

Fig. 2. Inactivation cross section of C-ion beams.

References
1) M. Miura and T. Sasaki: Radiat. Res., 123, 171 (1990).

Division of Radiation Hazards, National Institute of Radiological Sciences

115

RIKEN Accel. Prog. Rep. 28 (1995)

Sensitivity of Normal Human Skin Fibroblasts after
Carbon Ion Irradiation
H. Maezawa, T. Mori,* F. Yatagai, T. Kanai, and S. Inokuchi*
Knowledge for characteristics of normal tissue damages is important in successful radiotherapy with heavyions. The study was conducted to know RBEs (relative biological effectiveness) of the lethal sensitivity,
and the repair of lethal damages in human skin fibroblasts and keratinocytes after irradiation with heavyions. This paper reports the results in fibroblasts exposed to carbon ion.
Normal fibroblasts (HSF) were grown to a stationary phase in T25 flasks and irradiated with carbon
ion accelerated to 135 MeV/nucleon in RIKEN Ring
Cyclotron. Using the monoenergetic ion beam, theLETs were selected by inserting absober plates of appropriate thickness. Cell survival after irradiation wasdetermined from the colony forming ability. Figure 1
shows the survival of fibroblasts after carbon-ion irradiation. The shoulder of the survival curves after
irradiation by a carbon beam above 58.4 ke V / J.tm of
t he dose averaged LET was reduced or disappeared depending on the LET, compared to the shoulder after
irradiation with Co-60 gamma-rays. RBE at a given
LET was difined as the ratio of the dose required for
10% survival with the ion beams to that with Co-60
gamma rays. Resulted RBE at 22, 58.4, 97, 106.7,
and 266.8 keY / J.tm were 1.42, 2.40, 3.74, 3.81, and2.76, respectively. PLD repair has been investigatedwith the delayed plating technique in which cells were

C-12 mono I PLDR I HSF

C-121266.8 keV/um

HSF cells

t:

.2

.1

ti
~
u.
en
t:

':;:

"E

.01

+PLDR

:::l

(f)

Dose (Gy)Fig. 2. Survival curves of stationary phase fibroblasts
replated immediately after carbon-ion irradiation(- PLDR) and at 24 hrs after (delayed plating,C-12(13SMeV/u) I HSF+PLDR).
t:,.

22 keV/um.A . 58.4
C

.2
t;
f!
u.

o 97
10 -1
•

10~.7

o 266.8CIc'>~ 10-2
::l

UJ

2

4
6
Dose (Gy)810Fig. 1. Survival curves of fibroblasts irradiated with carbon ion and Co-60 gamma rays.

School of Medicine, Tokai University

116

replated at 24 hr (37°C) after irradiation. The survival after the delayed plating was higher as comparedwith that immediately after irradiation with carbon
ion at 97 and 266.8 keY / J.tm (Fig. 2). PLD repair was
clearly observed. The recovery ratio was calculated
from the survival after the delayed plating to a givendose, which reduced survival to 1% when cells were replated immediately after irradiation. Recovery ratios(1.6 at 97 keV/J.tm and 2.7 at 266.8 keV/J.tm) in cells
irradiated with carbon ion were smaller than that (5.6)
in cells irradiated with Co-60 gamma rays.
Present results suggested that carbon ion above 58
keY / J.tm produced less repairable damages in fibroblasts as compared with Co-60 gamma-rays.

RIKEN Accel. Prog. Rep. 28 (1995)

Mutation Caused by Heavy Ion Particles and X-rays
N. Shigematsu,* H. Ito, S. Yamashita, K. Toya,* A. Kubo,* F. Yatagai, and T. Kanai
The purpose of this study is to compare X-rays andheavy ion particles irradiation with regard to their effects on cell killing and mutation induction. We alsostudied how their irradiation procedures (single andfractionation) would affect cell survival and mutation.
V79 cells were irradiated by the heavy ion beam fromRIKEN Ring Cyclotron or by X-rays from MBR-1520R(Hitachi) and cell survivals were calculated by colony
assay. After one or two weeks expression periods, themutation frequencies at the hprt locus were calculated
from the numbers of colonies formed in media supplemented with 6-thioguanine (10 J.Lg/ml). The effects ofthe fractionation (3 hr interval) of radiation on the cell
survival and the mutation frequencies were also examined.
The Do values for 150 kV X-rays, 20 keY / J.Lm carbon beam, 80 keV / J.Lm carbon beam and 80 ke V / J.Lm
neon beam were 2.2 Gy, 1.8 Gy; 1.0 Gy, and 1.4 Gy, respectively (Fig. 1). As shown in Fig. 2 the extremely
higher mutation was caused by the heavy ion beamcompared with X-rays. A neon beam caused less mutation than a carbon beam under the same LET conditions. Both cell killing effect and the mutation induction were enhanced when LET of a carbon beam
was increased 4 times (20 to 80 keY / J.Lm). Our results
indicate that the heavy ion beam therapy had morezou

~ 10 1

"z
>
>

o

10
DOSE

12
( Gy )

Fig. 3. Survival curves for X-rays single (e), X-rays fractionated (0), carbon single (A) and carbon fractionated(t:,.) irradiation.
~ 2500"'0

C (SO)

2000"~ 1500~ 1000
z

o

500

3
::>

~

o

10
DOS E

Fig. 4. Mutation frequencies for X-rays single (e), X-rays
fractionated (0), carbon single (A) and carbon fractionated (t:,.) irradiation.

zoNe(80j

o

4

6

10
DOSE

12
( Gy)

Fig. 1. Survival curves for X-rays and heavy ion beams(carbon 20 and 80 keY //-Lm and neon 80 keY //-Lm) .

- 2500
~
-Co

"
u

2000

C ,SO l

r

/

1500

z

c 120)::>

8 1000
No,SO)z~

12( G y'

X -f:lY

500

<I

::>

~

0

4

10
DOSE

12
( G y)

Fig. 2. Mutation frequencies per 106 cells irradiated with
X-rays and heavy ion beams (carbon 20 and 80 ke V / /-Lmand neon 80 keY / /-Lm).
Dept. Radiol., School of Medicine, Keio University

powerful cell killing effect than X-rays while it caused
the high risk for mutation induction. A neon beam
has small mutation induction effect comparing with acarbon beam while the similar cell killing effect canbe expected from each of them. Comparison between
single and fractionated irradiation was shown in Figs.
3 and 4. A carbon beam had no significantly different
effects on cell killing between single and fractionated irradiation whereas X-rays had. When the carbon beamirradiation was fractionated, the mutation frequency
was reduced although the survival curve was not affected. When X-rays was used the mutation frequency
was almost the same in each way.
We concluded as follows:(1) The mutation frequency was extremely high forthe cells which were irradiated with a heavy ion beamcompared with X-rays.
(2) The mutation frequency was increased when the
LET of a carbon beam was increased.
(3) The mutation frequency was less for a neon thana carbon beam, suggesting that neon is a favorable
beam for the heavy ion therapy especially when treating with higher doses.
(4) When the cells were irradiated with a heavy ion
beam the fractionated procedure made it possible toreduce the mutation frequency without decreasing thecell killing effect.
117

RIKEN Accel. Prog. Rep. 28 (1995)

Effects of Accelerated Carbon-Ion on the Induction of DominantLethality in the Teleost Fish, Oryzias latipes
Y. Hyodo-Taguchi,* T. Kanai, S. Minohara, and Y. Furusawa
The dominant lethal mutation test with mice has
been considered one of the most important methods
for the estimation of the mutagenic effects of chemicals
on higher animals. In the small teleost fish, Oryzias
latipes, it has been reported that the dominant lethal
mutation test by using the hatchability of eggs is useful for estimation of the mutagenic effects of radiationand chemicals.1) In the present experiment, we havestudied the genetic effects of heavy ion on the malegerm cells of the fish by using the dominant lethal test
system.
One of albino strains of medaka (bi-3R) was used.
A single pair of the adult fish lays a cluster of 10-40
eggs almost every morning in a laboratory aquarium if
the fish were kept at 26 ac. During the period of 6-9
days before irradiation, the numbers of fertilized andunfertilized eggs laid by each pair and the hatchability of the fertilized eggs were examined to determine
non-irradiation control value. The male of each pair
was irradiated with carbon-ion (135 MeV lu) accelerated by the RIKEN Ring Cyclotron. The fish were
exposed to heavy ion of 2, 5, and 10 Gy at the mid position of spread-out bragg peak (dose average LET =70 ke V I J-Lm) . The irradiated fish were transported to
the NIRS and each fish was kept with a non-irradiatedfemale in an aquarium containing 21 of water. Eachpair was kept under conditions of about 26 ac and 14h light/10-h dark cycle and observed every day. The
numbers of fertilized and unfertilized eggs laid by eachfish were counted every morning and each cluster of
fertilized eggs was incubated separately in a petridish
at 26 ac. The incubation medium (D.W. containing
0.0001% methylene blue) was changed every day anddead embryos were removed. In the non-irradiatedcontrol, most embryos hatched 7-10 days after fertilization. The numbers of dead embryos and newly
hatched fry were counted every day in each cluster.
The hatchability was calculated as the percentage of
hatched embryos per fertilized eggs. The hatchabilityof the non-irradiated control was 92 ± 1%; the relative hatchability rate (RHR) was calculated as follows:(hatchability of the given group) I (hatchability of the

National Institute of Radiological Sciences

118

control group) x 100. Dominant lethal rates were calculated as 100 minus RHR. The maturation stage at
which spermatogenic cells were irradiated was judged
by the time between irradiation and fertilization. 2 )Thirty-one pairs of fish irradiated with carbon beam
were examined to estimate fertility and hatchability ofeggs laid for 30 days. A considerably high level of thefertility of the male fish was kept within 10 days after irradiation in all irradiated groups. At 20 and 30
days after irradiation a marked decrease in the fertility
was observed in the C-beam 10 Gy-irradiated group.
The hatchability changes showed that (1) the hatchability of eggs fertilized by irradiated males reduced
markedly within 3 days after irradiation, and the effects were dose-dependent and (2) the effects of irradiation decreased if the interval between irradiation andfertilization became longer than 4 days. From thesehatchability data, the dose-associated increase of production of the dominant lethality was observed in each
spermatogenic cell stage in medaka after heavy ion irradiation; a dose-dependent increase in the dominantlethality was found for sperm, spermatid and spermatocytes within this dose range, whereas no marked increase of the dominant lethality could be found forspermatogonia. Mature sperm was the most sensitive
among the various stages of spermatogenetic cells. The
high an~ low inducibility of dominant lethal in spermand spermatogonia, respectively, was reported in thisfish after X-irradiation. 1,3) .
On the basis the present results and the previous results from X-irradiated fish, it seems to be evident thatthe effect of carbon-beam on the induction of dominantlethality was about 2 times higher than that of X-rays
for sperm and spermatid of the fish.
References
1) N. Egami, A. Shimada, and A. Hama-FUrukawa: Mutat.
Res., 107, 265 (1983).
2) N. Egami and Y. Hyodo-Taguchi: Exp. Cell Res., 47,
665 (1967).
3) A. Shima and A. Shimada: Pmc. Natl. Acad. Sci. USA,88, 2545 (1991).

RIKEN Accel. Prog. Rep. 28 (1995)

Biological Dose Distribution of Carbon-12 Spread-Out-Bragg-Peakfor Tumor Controls
K. Ando, S. Koike, M. Iizuka, T. Aruga, N. Hori, T. Kanai, S. Minohara, M. Sudou, and F. Yatagai
The clinical trial of heavy charged particle therapy
started June 23 , 1994 at National Institute of Radiological Sciences. Biological effectiveness of therapeutic beams against tumors inactivation is of great concern for designing a range modulator which generates
Spread-Out-Bragg-Peak (SOBP) . A range modulator
for 135 MeV/nucleon carbon-12 was designed by T.
Kanai, and has been proven to exert fairly homogeneous cell kills against cultured V79 cells. 1) We here
investigated and reported whether or not the SOBP
made by the range modulator could also achieve homogeneity in tumor controls. (Materials and Methods) The NFSa fibrosarcomas were transplanted intohind legs of syngeneic C3H male mice. Seven througheight days after transplantation when leg tumors grewto 7- 8 mm in diameter, mice locally received single
doses of irradiation to their leg tumors. Desired tumor positions within 3-cm SOBP were obtained byplacing thick Lucite plates in front of tumors. Cs-137
gamma ray was used to reference to obtain relative biological effectiveness (RBE) of carbon-12. After irradiation, tumors were (a) monodispersed by trypsin toserve lung colony assay for determining cell survivals,(b) measured by calipersonce a week up to 4 months
to serve for tumor control assay (TCDsoj120)' A total of 1050 mice were used for the experiments. (Results) Leg tumors were located at three SOBP positions; proximal-(LET = 61 keY / {Lm), middle-(LET =78 keY / {Lm) and distal-(LET = 108 keY / {Lm) SOBP.
(Fig. 1). Unmodulated plateau (LET = 23 keY / {Lm)
was also included. Radiosensitivity of the tumor cells
determined by lung colony assay showed that Do values
for distal- , middle-, proximal-SOBP, and unmodulated
plateau were 1.12, 1.48, 1.49, and 2.68 Gy, respectively.
Do for gamma ray was 4.22 Gy.
Tumor control probabilities for each position of

,

1.4 ~

P.F;g. 1/ 941113A -..:

l-ooseL

QI

c

~

Qi

0.8

l

proximal

0.6 r«~.~ -~,. . .".
IV

o

10

20
30
40
Depth In Water (mm)3r---~---.----.---~

Tumor Control probability~•

Physical Dose
Biological Effect

0.5
plateau

proximal Middle Dlltal

S08P

S08P S08P

Fig. 2. Distribution of biological effectiveness within
Spread-Out-Bragg-Peak. Biological effectiveness is normalized by unmodulated plateau beam.

It is concluded that homogeneous cell kills of amouse tumor was achieved by the range modulator design of which was based on the data of Chinese hamster
cells in vitro.

1/1o

SOBP were determined 120 days after irradiation.
TCDso/120, i.e., radiation dose required for 50% of
tumors controlled, was 32.5, 34.9, 37.1, and 56.4 Gy
for distal- , middle-, proximal-SOBP and unmodulated
plateau, respectively. RBEs of carbon-12 relative togamma ray (TCD so/ 12 = 83.2 Gy) were 2.56, 2.38,
2.24, and 1.48 for distal-, middle-, proximal-SOBP andunmodulated plateau, respectively.
Biological effect at each SOBP was obtained bycomparing biological doses (Le., the product of physical dose and RBE) between SOBP and unmodulated
plateau, and used to evaluate homogeneity of tumor
inactivation within SOBP. As for lung colony assay, biological effects at surviving fraction (SF) of 0.5 down
to 0.1 , was ranging between 2.2 and 2.69, indicating
fairly homogeneous effectiveness within 3-cm SOBP.
Tumor control assay also resulted in homogeneity similar to colony assay; biological effects for tumor controls were 2.25, 2.2, and 2.05 for proximal-, middleand distal-SOBP (Fig. 2).

50

Fig. 1. Positioning of tumors within 3-cm Spread-OutBragg-Peak for 135 MeV/nucleon carbon-12. Arrowlength corresponds to tumor thickness.

References
1) T. Kanai and Bio-Phys. Group of RIKEN Ring Cyclotron Users: Proc. 3rd Workshop on Physical and Biological Research with Heavy Ions, eds. K. Ando and
T. Kanai, NIRS-M-99, HIMAC-006, Natl. Inst. Radiol.
Sci., p. 7 (1993).

1195. Instrumentation

RIKEN Accel. Prog. Rep. 28 (1995)

Production of a Low-Energy Polarized Neutron Beam
K. Sagara, N. Nishimori, T. Flijita,* H. Akiyoshi,* K. Maeda, and H. Nakamura*
To produce a 10-18 MeV polarized-neutron beam
whose polarization is precisely known, a neutron-beamgenerator using D(tt: ii)3He reaction and a deuteronbeam polarimeter using 3He(J:p)4He reaction havebeen developed. In this energy range, D(tt: ii)3He reaction has the highest figure of merit for the it-beamproduction and 3He(ct:p)4He reaction has high analyzing powers which vary smoothly with the incident
energy and the scattering angle. The generator andthe polarimeter will be combined with an intense d-beam from the RIKEN AVF cyclotron to make highprecision polarized-neutron experiments on, for example, ii + d scattering.
Figure 1 shows a D2 gas target for the ii-beamproduction and a 3He gas target for the d--beam po-

d

o

D2

5 em

~SD

Fig.
1.
A polarized-neutron-beam generator using
D(J: n)3He reaction and a deuteron-beam polarimeterusing 3He(J:p)4He reaction. The d-=-beam is stopped on
the bottom of the 3He-gas cell.

larimeter. A number of background neutrons weregreatly reduced by adopting heavy metals for a beam
slit (W), for 3-J.Lm-thick window foils of the target gas
cells (Ta) and for a d--beam stopper (Ta). The walls of
the gas cells were made thin to reduce the scatteringof neutrons by them.
For example, a 12-MeV ii-beam in the 0° direction
is generated by D(tt: ii)3He reaction at Ed = 9 MeV.
The energy spread of the ii-beam comes mainly fromthe d--beam energy loss of 140 keV in the D2 target of
2 bar x 4 em in thickness. As the continuum neutrons
from D(d~ n)pd reaction have energies below 6.77 MeV,
their contributions may be well separated by the TOF
technique. The ii-beam flux in a solid angle of ±1.5° x±3° is estimated to be 6 x 106 particles/sec for a 5 J.LA
d--beam.
When the deuteron spin axis is in the y (up) direction, the polarization of the ii- beam (p~) is expressedasThe vector and tensor components of the d--beam'polarization, P~ and P~y, are measured by the 3He(d,p)
polarimeter. We have already made accurate measurements of the analyzing powers Ay and Ayy of 3He( tt: p)reaction in the range of Ed = 6.6-15.4 MeV. As p~
is mainly determined by p~, the polarimeter counters(Fig. 1) are placed at the angle for the maximum of
A y . By this polarimeter, the d-- beam polarization canbe determined within an accuracy of 0.6%.
Precise measurement of K:(OO) and Azz{OO) ofD(ct: ii)3He reaction is in progress at Kyushu University tandem accelerator lab. The ii-beam polarization
p~ is measured using 4He(ii, n) scattering. The liquid helium target (used also as a scintillator) has already been installed and the measurement of p~ hasbeen started using the Ay = 1 (theoretically maximum) point of 4He(ii, n) scattering at 12 MeV.
A high-intensity polarized-neutron beam of energyof 10- 18 MeV whose polarization (about 0.5) is known
to within about 1% will be available in the near future.

Department of Physics, Kyushu University

121

RIKEN Accel. Prog. Rep. 28 (1995)

Germanium Counter Telescope for Gamma-Ray
Position Sensitive Detection
Y. Gono, E. Ideguchi, K. Miyazaki, T. Morikawa, T. Kishida, and M. Ishihara
We reported last year the concept as well as theresults of simulation calculations of a Ge counter
telescope. I) A segmented Ge (S-Ge) detector has been
produced following our specifications and delivered by
a company, URISYS MESURES. This special detector
is prepared to be used to give position information bya signal of Compton scattering. Then an energy information is given by summing signals of both Compton
scattering in S-Ge and a totally absorbed signal in a
Ge detector placed behind the S-Ge.
The first test was made to check energy resolutionof each segment. In this test a highly integrated linear
amplifier was developed in the tandem laboratory in
Kyushu university. Four linear amplifiers were assembled in one span NIM chassis. This type of amplifier
was prepared to handle 25 signals from every segment
independently. Amplifier gains were adjusted to give asame pulse height for each segment though each preamplifier gives much different pulse height for a fixedenergy ,-ray. Then energy resolutions were checked
for every segment and the resulted values are given in
Fig. 1.

chassis.
The summed ,-ray spectrum was also tested. In thiscase a 20% HPGe detector was used as a rear detector with NaI(TI) anti-Compton shield. A 152Eu ,-raystandard source was used. The resulted spectrum isshown in Fig. 2 with a spectrum taken by an S-Ge
alone. Two spectra are shown by normalizing the peakheights of 1408 ke V peaks in both spectra. The low energy continuum back ground in the summed spectrum
is significantly reduced as expected.

1000
CIlAMK!L NUIlIEl

21
2.7 keY63
2.6 keY7
2.5 keY8
2. 7keV12112.4keV

16
21

2.6keV

2.5keV20

19

23
2.6keV

2.6 keY

2.8keV

2.5 keV

2.5 keV25

24
2.5 keVFig. 2. ,-ray spectra taken in singles mode (A) by an
S-Ge alone and a summed mode (B).

2.4keV

15

14

18

22
2.3keV

2.5 keY

2.5 keY

2.6keV

2.7 keY

10

9

13

17
2.4keV

2.7keV

2.5 keY

2.5 keY54
2.7 keY

2.71ceVAs a conclusion it was · proved that a Ge counter
telescope by using an S-Ge as a ~E counter works to
reduce considerably a back ground and to give position
information simultaneously. Also it may be worthwhile
to point out that this detector can be used as an efficient polarimeter of ,-rays.

Fig. 1. FWHM of each segment at 1.33 MeV.

These values are not much different from the values
measured using commercially available spectroscopy
amplifiers which have 1 channel for one span NIM

122

References
1) E. Ideguchi et al.: RIKEN Aceel. Prog. Rep., 27, 121(1993).

RIKEN Accel. Prog. Rep. 28 (1995)

A New Position Sensitive Silicon Detector for Experiments ofSuper Heavy Nucleus Search
M. Kurokawa, T. Motobayashi, H. Murakami, T. Uchibori, A. Yoshida,
K. Morita, Y. Pu, and T. Nomura
A new position sensitive silicon detector has beendeveloped for super heavy nucleus-search experiments.
In the experiments, a heavy element can be identified
by measuring the energy of its successive a decays. To
reduce accidental correlation the detector should havehigh position resolution. The detector developed is adouble-sided position-sensitive silicon detector as illustrated in Fig. 1. The total effective area is 64 mm x 64
mm. The energy signal is extracted from the front side
electrodes, and two-dimensional position information,x and y in this figure , is obtained from the front andback sides, respectively.

signalsignalyLxconnecting every other strips up to 16 with 120 0 resistance. Signals are read out from the two ends of thechain.
To reduce the position resolution, the difference between the position signals corresponding to a fusion
product 205Fr from the 40 Ar + 169Tm reaction and its
a decay was measured. The results are shown in Fig.
2. The energy dependence of the position resolution
is roughly expressed as liE. This position resolution(x x y) of the newly developed detector is better thanthat of the detector 2) used in the previous experiment 3)
by a factor of 100. This detection system was used in
the experiment of 232Th + 40 Ar reaction.

0.5,-------------------.,

1

0

.4

.~ 0.3signal1':; 0.2:~~ 0.1
0.00L---'---4'--26'---8'---1"'-:-0---,l"'-:-2--.L..---'
14
Energy (MeV)

3.0

"-

The front surface of the detector is divided into 12
resistive strips. This small number of the strips is intended to achieve a small total dead space which isformed between the strips, as well as to reduce thenumber of electronics. To obtain more precise x information than the width of a strip, the charge division method is employed. In contrast to the usualdesign where the charges are extracted from the top
and bottom ends of a strip, two readout electrodes are
running along the side edges of a strip. Because theposition resolution is inversely proportional to the resistance between electrodes,l) a high surface resistivityof around 10 k02 was required in the present design.
This was realized by the "shallow doping" technique inthe implantation process. The doping density is almost
ten times lower than the normal level.
The back side of the detector is designed to bea microstrip structure. The total number of electrodes is 128 and eight resistance chains are formed by

(b)

2.5

Fig. 1. Schematic view of the detector.
~

E
~

<::

2.0

•

1.5

.9-

•

~ 1.0
0.5
0.0

0

14

2
Energy (MeV)

Fig. 2. Energy dependence of horizontal (a) and vertical(b) position resolution.
References
1) F. Eland and R. Sareen: IEEE Trans. Nucl. Sci., NS21, 75 (1974).
2) M. Kurokawa et al.: RIKEN Accel. Prag. Rep., 25, 120(1991).
3) T. Nomura: Proc. Workshop on Heavy-Ion Reactions
with Neutron-Rich Beams, ed. M. Ishihara, World Sci.,
p. 269 (1993).

123

RIKEN Accel. Prog. Rep. 28 (1995)

Status of the Detector System at SMART-FPl
H. Okamura, S. Ishida, N. Sakamoto, H. Otsu, T. Uesaka, T. Wakasa, Y. Satou, H. Sakai, T. Niizeki,
K. Katoh, T. Yamashita, and T. Ichihara
The first focal plane (FP1) of the SMART spectrograph is primarily used to measure the (d, 2He) reaction. The energy resolution as well as the 2Hedetection efficiency was significantly improved by the
newly fabricated detector system.!) The angular resolution, however, was still very bad due to the large
magnification in the vertical direction. This is a serious drawback since (d,2He) is a three-body reaction
and the precise angular information, particularly forthe light target, is required to determine the excitation energy as well as the scattering angle.
In the "standard" optics which has been used sofar, the field strength of the Q-magnet is chosen sothat the scattered particles with the central momentum are focussed in the vertical direction. Although
the large angular acceptance is maintained in the wide
momentum range, the angular resolution at the central momentum is significantly deteriorated due to themultiple-scattering by the vacuum window and by thewire chambers.
The new optics has been introduced as a compromise
between the better angular resolution and the large acceptance. The field of the Q-magnet is chosen to berelatively strong so that the scattered particles are focussed at the high-momentum side in the vertical direction. Also the focal plane is shifted upstream, to thearea between the two wire chambers, which will leadto the improved momentum resolution. The propertyof the new optics has been studied by using the elastically scattered protons from a gold target at Ep = 135
MeV. The result is summarized in Table 1 comparedwith the standard optics. The quality of data for the
Table 1. Summary of optics properties at Ep = 135 MeV.

PQl
PQ2
PDl

88
8cp
8p/p

(8E)
(88)

Standard optics
New optics
Magnetic Field
353.0 Gauss/em
392.6 Gauss/em
163.6 Gauss/em
189.2 Gauss/em
7241 Gauss
Acceptance~100 mrad a )84 mrad~200 mrad a )156 mrad~20 msr a )13.1 msr±12%+6/-8 %
Resolution
4 mrad4 mrad5-30 mrad a )5 mrad
1-3 X 1O- 3a )1 X 10- 3(d, 2 He)- Resolution
8(El + E2) = 700 keY 8Ex = 460 keyb)
unknown
9 mrad b )a) ~n, 8<p and 8p/p depend on p in the standard

optics.
b) obtained from the three-body calculation.

124(d,2He) reaction is significantly improved by using thenew optics as is shown in Fig. 1.

3 .0
1+

12C(d,2He)

I

GND

>

460keV

ILl

:::il
i..
rn

'-...

E d =270MeV

2.0

1.0

(Jcm=O-l°12"2+41: 4.5

.D

5
~

C
"ti
'-...
b
"ti

0 .0

(Jcm= 6-8 0
0.2

11: 2 . 6 2 - -I

2~:O.95--

1 I

0.0 ~~-"""'-"'--""--->"--"-------I
1.0

ti

~ti

0.5

0.0

o
12B

5

10

15

20

25

Excitation Energy (MeV)

Fig. 1. Typical excitation energy spectra of the (d,2He)
reaction obtained with the new optics.

Also the polarized deuteron beam has become available at SMART. By using the Wien filter, the polarization axis can be rotated to the normal or sideway
direction of the scattering plane at any angle of thebeam swinger. 2) A polarimeter has been installed at
the exit of the beam swinger and the polarization at
the target is directly measured. 2) The polarimeter target can be quickly inserted and removed by using apneumatic actuator, which allows the periodical monitor of the beam polarization during the experiment.
This feature was used in the first measurement of theanalyzing powers of the (d,2He) reaction. Details of
the experiment are described elsewhere. 3)
References
1) H. Okamura et al.: RIKEN Accel. Prog. Rep., 27, 113(1993).
2) H. Okamura et al.: AlP Conf. Proc., 293, 84 (1994);
RIKEN Accel. Prog. Rep., 27, 130 (1993); This report,
p.148.
3) H. Okamura et al.: Nucl. Phys., A577, 89c (1994);
Phys. Lett., B345, 1 (1995); This report, p. 148.

RIKEN Accel. Prog. Rep. 28 (1995)

Construction of the Deuteron POLarimeter DPOL at the Second
Focal Plane of SMART
S. Ishida, H. Okamura, N. Sakamoto, H. Otsu, T. Uesaka, T. Wakasa, Y. Satou, S. Fujita, H. Sakai,
T. Ichihara, T. Niizeki, K. Katoh, T. Yamashita, Y. Hara, and K. Hatanaka
Polarization transfer measurement for inelastic
deuteron scattering is one of the most efficient probesof isoscalar spin excitations which we have little information up to now. Spin flip probability 8 1 in the (d,d')reaction will be a signature of spin excitations as Snn
is in the (p,p') reaction. 1 ,2) Sl is written, in terms ofpolarization observables, as
1

I

I

I

We are constructing the Deuteron POLarimeter
DPOL at the second focal plane (FP-2) of the SMART
spectrograph to measure the polarization of scattereddeuterons. It is designed to measure all the vector(itll) and tensor (t 20 , t21 and t 22 ) polarization components by utilizing following three reactions. (Table 1)
Table 1. Reactions and corresponding components ofanalyzing power.

I

8 1 = -9 (4 - Py y - A YY - 2KYY )YY'
where yy denotes the tensor polarization and pY' Y' ,Ayy and K~~yJ are the tensor polarizing power, thetensor analyzing power and the tensor-tensor polarization transfer, respectively. Thus measurements of thetensor-polarization observables are needed to extract
8 1 via the (J,J) reaction.

Reactions

Analyzing powers

1 : d + 12C --t d + 12C
2:
d + P --t 2He (2p) + n
3:d+p --t d+p

iTll
T 20 and T22
all components

These reactions are measured semi-inclusively. The

SIDE-VIEW

HOOI

Han/~~jlL-----~-7d~---=~------------------<:::: -·-111--II
II iron'''''-J eM.!

- - - - - ---- -plastic scintillators

I
-1
CMl

absorbers
diStance from the scatterer (m), , , , , I , , , ,1, , , , ' ., , , , I, , ' , I , , , ' , , , , , I, , , "., , , , , , , , , '

o

1

2

3

4

Fig. 1. A cross sectional view of the Deuteron POLarimeter DPOL. Details aredescribed in the text.

geometry of DPOL is shown in Fig. 1. Note that thereaction plane of SMART is vertical because a scattering angle is changed by using a beam swinger system.
A multi wire drift chamber (MWDC) and trigger
plastic scintillators (0.5 x 18 x 80 cm 3 and 1.0 x 18 x
80 cm 3 ) are used for detecting scattered deuterons.
These plastic scintillators containing C and Hare
also used as active scatterers for double scattering.
The polarimeter-system consists of three hodoscopes,

HOD1 (28 times 6.5x6.5x220 cm 3 ), HOD2 (12 times
6.5x6.5x220 cm3 ) and HOD3 (2 times LOx 13x 100
cm 3 ), and two calorimeters, eM1 (6 times 1.0x29x220
cm 3 with 1.8 cm thick iron absorbers) and CM2 (2times 1.0 x 29 x 220 cm3 with 1.8 cm thick iron absorbers). For all hodoscopes and calorimeters, plastic
scintillators are used and they are viewed at both ends
by photomultiplier tubes.
Three kinds of triggers for double scattering events

125

corresponding to the three different reactions are
made. For the 12C(d,do) event, calorimetry usingiron absorbers and scintillators is employed to identify deuterons. For the 1 H(d,2He) and 1 H(d,d) event,
two charged particles are detected in coincidence.
The first experiment for testing the polarimetersystem has been recently performed with a 270 MeV
polarized deuteron beam extracted from the RIKEN
Ring Cyclotron.
Three combinations of the beam polarization wereused in this experiment and their ideal values of vector and tensor polarization are (pz ,pzz) = (0,-2) ,( -1 , + 1) and (+ 1,+ 1), respectively. The polarization
axis was controlled with the Wien filter downstreamof the ion source so that it lay on the normal or sideway direction of the scattering plane at FP-2. The
beam polarization was monitored by using the d + P
scattering at 270 MeV and typically 60- 65 % polarization of the ideal value was obtained throughout theexperiment.
Figure 2 shows the preliminary results of the effective analyzing powers for the 12C(d,do) events. Large
iTll values are obtained, which is consistent with theresult of POMME.3) Further analysis and improvement of the polarimeter are now in progress.

126

12C(d,do)

0 .3

E d = 270MeV

0.2
0 .1

10

15

20
0 .2
0.1

0.1
0 .0

f-------------,,---l- 0 .1

T22

0 .0- 0 .1

10

15

20

5

10

15

20

8 1ab(deg .)Fig. 2. Preliminary results of the effective analyzing
powers of DPOL for the 12C(d,do) events.

References
1) S. Ishida et al.: Phys. Lett., B314, 279 (1993).
2) M. Morlet et al.: ibid., B247, 228 (1990).
3) B. Bonin et al.: Nucl. Instrum. Methods Phys. Res. ,A288, 389 (1990).

RIKEN Accel. Prog. Rep. 28 (1995)

PPAC for Beam Profile Monitor at the RIPS
H. Kumagai and K. Yoshida
A position sensitive parallel plate avalanche counter(PPAC) was constructed as a focus-plane detector forthe secondary beam separator RIPS.!) Two PPAC's
were placed at the first and the second focus planes (F 1
and F2) of the RIPS to measure x- and y- positions andtime-of-flights of beam particles. Other two PPAC's
were set in front of the third focus plane (F3) in orderto obtain the beam profile at F3 where the user target
was set up.
The structure of electrodes of the PPAC is shownin Fig. 1. As seen, the electrodes provided a sensitive
area of 100 x 100 mm 2 and were composed of an anodeand two cathodes which were used to determine theposition of x- and y- direction. They were placed inparallel with 4 mm apart from one another in orderof x-cathode, anode, and y-cathode. The anode wasmade of 2.5 f..£m polyester foil , both sides of which werecovered with a 40 f..£g/cm 2 gold. The cathode was a 2.5
f..£m thick polyester foil on which 50 gold stripes were
deposited to 80 f..£g/ cm 2 in thickness. The width of
stripes was 1.6 mm with a 0.4 mm inter-stripe gap.
All the contiguous stripes were connected each otherwith 510
chip resistors. The detection of positions
was accomplished by the charge division technique forthe charges induced on the cathode strip by avalanche.

nCathode-X1

Cathode-X2

The electrodes were placed in a small aluminum box(184 x 160 x 48 mm3 ) in which isobutane of 6-10 Torr
was filled as a counter gas. The entrance- and exitwindows were made of 4 f..£m polyester foil coated with
50 f..£g/cm 2 aluminum. The PPAC was operated withthe anode bias of 600-800 V.
The signals from both ends of the resistor array ofthe cathode were amplified by a charge sensitive preamplifier and a shaping amplifier (T = 2.5 f..£s) andwere sent to CAMAC ADC's. The signals were analyzed by a PC9801 personal computer. One- and twodimensional position spectra could be displayed on amonitor screen in real time mode. In the spectra, thepeaks corresponding to the stripes were well separated.
The position resolution obtained was 2 mm, although
the FWHM of the peaks was much smaller than that.
This resolution was enough for measuring the beamprofile at F1 and F2. For the profile at F3, however,
the resolution was not so good since the profile wasdeduced by the extrapolation from the position information of two PPAC's located at the upstream of F3.
The time signal was obtained from the anode signal by using a fast amplifier (rising time <1 ns,
gain = 500) and a constant fraction discriminator.
The time resolution of 0.46 ns (FWHM) was achievedfor 41 MeV/nucleon 18 0. The particle identification
was accomplished with the timing information fromthe PPAC and the energy loss signals from the SSD(50 x 50 x 0.3 mm3 ) which was placed just after the
PPAC.
The PPAC's were installed in RIPS five years ago
and since then they have been worked well. In order to improve the position resolution, new PPAC's(100 x 100 mm2 and 150 x 100 mm 2 ) are now underconstruction. The position resolution is expected to beless than 1 mm by using the cathodes with stripes of
1 mm width.
References

Cathode Strips

Fig. 1. The structure of electrodes.

1) T. Kubo, M. Ishihara, N. Inabe, H. Kumagai, I.
Tanihata, K. Yoshida, T. Nakamura, H. Okuno, S.
Shimoura, and K. Asahi: Nucl. Instrum. Methods Phys.
Res., B70, 309 (1992).

127

RIKEN Accel. Prog. Rep. 28 (1995)

Polarized Xe Stopper for the Measurement ofMagnetic Moment of Unstable Nuclei
H . Sato, Y. Hori, K. Mochinaga, M. Adachi, and K. Asahi
Polarized unstable nuclear beams produced by the
projectile fragmentation reaction are very useful tools
for the measurement of magnetic and quadrupole moments of unstable nuclei. Up to now, our grouphas succeeded in measuring magnetic and quadrupole
moments of several neutron-rich nuclei produced at
RIPS. 1,2) It is also true, however, that the above
method of polarization based on the projectile fragmentation is not applicable to a certain class of nuclides. For example in the case of 11 Be, the nucleus ofconsiderable interest exhibiting the neutron halo andthe anomalous spin and parity, no appreciable polarization was obtained in our previous experiments using
the above method.
In this report we discuss a new method of obtaining
polarized unstable nuclei, which comprises the implantation of fragment nuclei in a highly polarized stopper
and the subsequent transfer of the host nuclear polarization to them through dipole-dipole interaction. Recently, it has been reported that a 129Xe solid whose
nuclear spins are highly polarized can be produced andits spin relaxation time becomes very long in a certain
condition (about 500 hours at 1 kG and 4.2 K). 3) We
consider this material as a good candidate for the polarized stopper, which would provide a large spin polarization and a long relaxation time. We begin ourstudy for obtaining the polarized Xe solid by polarizing gaseous Xe.
The 129Xe nuclear spin can be polarized by spin exchange with a polarized Rb atom. In this method, theRb atomic spin is polarized by resonance absorptionof a circularly polarized light of 795 nm wave length,
and its polarization is transferred to the 129Xe nuclear
spin during the formation of a Rb-Xe van der Waals
molecule. 4 ) The 129Xe polarization Px e depends on the
Rb polarization PRb , the spin exchange rate [se andthe wall relaxation rate
The time evolution of the
129Xe polarization is written asrw.

if we start the optical pumping at t = O.
We started the experiment to polarize gaseous 129Xe
nuclei. A natural Xe gas (26.4% 129Xe) of 610 Torr wascontained in a cylindrical glass cell (2.2 cm in diameter, 4 cm or 8 cm long) together with an N 2 gas of128

50 Torr and a small amount of Rb. The glass cell was
illuminated by a circularly polarized light generated by
a 2 W Ti:sapphire laser. The 129Xe polarization thus
obtained through the optical pumping was determined
experimentally by measuring its magnetization with anadiabatic fast passage NMR method (Fig. 1).

-~

o
-100

~ -200{I}-300~ -400-500

69.10- 67.40.L-.......................J..-.o..............-I.......o..-";O:::»,. 63.20
8
10
4
6
time (sec)...::;;......o.....o-..L.-.o................

o2

Fig. 1. Typical adiabatic fast passage NMR signal of polarized 129Xe gas. The signal shown by the curve represents the transverse polarization which appears when
the resonance condition is met. In this case, the signal
height corresponds to PXe = 3.5%. As indicated at thebottom by the solid line, the magnetic field is swept
through the resonance condition twice.

We made several glass cells and measured the 129Xe
polarization. Up to now, ' a polarization of 3.5% has
been reached. We also measured the spin relaxation
rate and the Rb polarization. As a result, we foundthat the relatively small value of P Xe was due to asmall Rb polarization, which may stem from a loss of
the laser power due to reflection on the surface of theglass cell or from Rb oxidation due to possible impurities in Xe gas. We are improving the system in orderto get higher 129Xe polarization. We also plan to construct an apparatus for producing a polarized Xe solid
for the measurement of the magnetic moment of 11 Be.
References
1) H. Okuno et al.: Hyperfine Interact., 78, 97 (1993).
2) H. Veno et al.: ibid., 84, 371 (1994).
3) M. Gatzke et al.: Phys. Rev. Lett., 70, 690 (1993).
4) G. D. Cates et al.: Phys. Rev., A45, 4631 (1992).

RIKEN Accel. Prog. Rep. 28 (1995)

A Recoil-Ion Momentum Spectrometer for
Atomic Physics Experiments
O. Jagutzki, T. Kambara, Y. Nakai, Y. Awaya, and H. Schmidt-Bocking
In order to investigate many-particle reaction dynamics in atomic collisions a novel high-resolution
technique has been developed, which determines themomentum and the charge state of the slowly recoiling target ions. Using a very cold and localized supersonic gas jet target a momentum resolution of better
than 0.1 atomic unit (a. u.) is obtained by measuring
the recoil-ion time-of-flight and the recoil-ion trajectory. Due to a detection efficiency of nearly 47r thistechnique is well suited for many-particle coincidence
measurements and enables various highly differential
experiments in atomic physics.
Such a Recoil-Ion Momentum Spectrometer was installed and tested at RILAC in collaboration with theInstitute for Nuclear Physics of the University Frankfurt. Target gas (He, Ne, Ar, ... ) is precooled to atemperature of 30 K (for He) at a pressure between
200 and 1000 hPa by a standard cryo-generator. The
precooled gas expands through a 30 J-Lm¢ nozzle forming a supersonic gas jet. Special care has to be taken tomeet the criteria for the supersonic expansion. Due tothe properties of the supersonic expansion, the target
gas is cooled to an internal temperature of about 0.1 K.
This corresponds to a Maxwellian momentum spreadfor helium atoms of less than 0.1 a.u. in any direction,
thus enabling spectroscopy of a helium ion recoil momentum with such precision. The center part of thegas jet passes after 6 mm through a 0.5 mm skimmer
hole into the target chamber and is thus collimated to anarrow beam. The ionizing projectile beam (e.g. fromRILAC) intersects the gas jet defining a target region
limited by the size of the spatial overlap between gas
jet and' projectile beam.
This target is located in the extraction region of thespectrometer (see Fig. 1). The spectrometer consistsof this extraction region, a field free drift zone and a
two-dimensional position sensitive multi-channel-plate
detector with a wedge-and-strip anode (PSCD). Recoiling ions produced in collisions of the projectiles
with the gas jet atoms are extracted by a well-defined
weak electrical field (typical of 1 V / cm). Then the ionspass a field free drift region and are detected on the
PSCD. Special care has to be taken to ensure proper
field conditions in the spectrometer. The extraction
region is shielded by wires defining potential lines toguarantee a homogeneous field. All surfaces are coatedwith carbon to avoid contact potentials.
From the trajectory and flight time of an ion it ispossible to determine the transferred recoil momentum in the collision by applying simple equations. The

I-----+------l2cm

Fig. 1. Sketch of the recoil-ion momentum spectrometer.

trigger for the time-of-flight measurement can be thedetection of the outgoing projectile or the use of apulsed beam. The electrical field can be selected sothat different charge states can be separated, and thatthe recoil determination with 47r is unambiguous for
all three dimensions. The finite size of the target restricts the attainable momentum resolution. However,
it is possible to reach for all three dimensions the maximum precision limited by the Maxwellian momentum
spread due to the finite internal gas jet temperature.
Transverse to the jet axis, the resolution can be evenbetter.
At RIKEN and several other atomic physics facilities a variety of different experiments are currently inprogress to exploit the unique opportunities offered bythis novel high precision spectroscopy method. 1-3)
References
1) V. Mergel et al.: accepted for publication in Phys. Rev.
Lett.
2) J. Ullrich et al.: accepted for publication in Comments
in At. Mol. Phys.
3) T. Kambara et al.: This report, p. 75.

129

RIKEN Accel. Prog. Rep. 28 (1995)

Attenuation Length of Scintillation Photons in
Liquid Rare Gases and their Mixtures
K. Masuda, N. Ishida, T. Doke, H. Okada, T. Komiyama, K. Hasuike, M. Shinoda, M. Sato,K. Terasawa, T. Kato, M. Suzuki, and M. Kase
Liquid xenon (LXe) is very suitable for radiation detectors of gamma-rays and energetic particles becauseof its large density and high atomic number. LXe canbe operated not only as ionization detectors but also
as scintillators. It has a large light yield (6.8 x 104 photons/MeV) and fast decay time (3- 20 ns).l) Therefore
it will be possibly used in nuclear and particle physics
in near future. The critical factors for detection of LXescintillation photons are the reft.ection of the scintillation light (174 nm) on detector walls and the attenuation length of the light in the liquid.
In order to investigate the above factors separately,
we have developed an almost complete anti-reft.ector,
which has a zigzag shaped surface so that the incident
light does not go out from the surface due to multiple reft.ection. 2 ) An 80 cm long scintillation detector
was used and the reft.ector was installed in the chamber. To measure the attenuation length, heavy ionsfrom the RIKEN Ring Cyclotron were entered at different positions in the chamber. The scintillation photons produced in the liquid were detected by a photomultiplier after the wavelength in a VUV region was
shifted to visible with sodium salicylate coated on a
Pyrex window. Ions of 12C and 14N with the energyof 135 MeV/nucleon and 15N with the energy of 115
MeV /nucleon were used. Ranges of ion tracks in theliquids are estimated to be 20 mm to 40 mm, dependingon the combination of incident ion and liquid. Detailsof the apparatus including a gas purification system
are described in a previous report. 3)
Previously3) the attenuation length of scintillation
photons in LXe was reported to be about 30 cm whichis rather short compared with the value we expected.
Therefore we have measured the attenuation lengths inother rare gas liquids and their mixtures to understandthe result for LXe.
The light yields obtained experimentally were normalized to the solid angle for photon detection andplotted in Fig. 1 as a function of the distance between
the heavy ion beam and the Pyrex window. From theposition dependence of the relative light intensity, theattenuation lengths were calculated. The values are
68 cm in liquid argon (LAr), 84 cm in liquid krypton(LKr), 30 cm in LXe, 200 cm in LAr + Xe (3%) and130 cm in LKr + Xe (3%). These results are summarized in Table 1. The table shows a matrix of the hostliquids and the wavelengths of the scintillation.
The wavelengths of the scintillation are 128 nm, 147
nm and 174 nm in LAr, LKr and LXe, respectively.
In Ar-Xe mixture or Kr-Xe mixture with enough con-130

i ~ -: :~-:~: ~~~:~~~ ~~_--:~:- ~-~_~:~
1---- ---- --- ---------- -I------- - -------.---~ -----------

.Ar
-IT

AXe

o Ar+Ieo IT+Xe... -........ . . ...... -_ ... ---_ ... _- ..... -- .. ------ ----------A---------- ------------~---------

0.1 I..--_--'L.....-_----L_ _---'-_ _---I
200
400
600
o

Distance<_>

Fig. 1. The measured light intensity divided by the solid
angle versus the distance between the ion track and the
Pyrex window. The relative light intensity is normalized to unity at the distance of 137 mm.
Table 1. The attenuation lengths in cm of the scintillation
photons.
LiquidArgon
KryptonXenon

128 nm68

Wavelength
147 nm 174 nm
200
84

137

30

cent ration of Xe, the wavelength of the scintillation isconverted to 174 nm from Xe excimers through theenergy transfer from Ar or Kr molecules to Xe.
Comparing the results for different wavelengths inthe same host liquid, which means the same molecular
structure and the same temperature, one can see thatthe scintillation light with the longer wavelength has
the longer attenuation length both in LAr and LKr.
One of possible explanations for this tendency may be
the Rayleigh scattering of photons with liquid atoms.
The scattering cross section has the wavelength dependence as the inverse forth power under an approximation, and the relation of the attenuation lengths experimentally obtained for different wavelengths is consistent with the scattering. If the present light attenuation is due to the scattering, one can collect mostof photons including scattered photons by using reft.ectors on the detector wall or by doping the liquid withwavelength shifters. So, further study to measure thelight collection with reft.ection mirrors will be done.
References
1) T. Doke: Portugal Phys., 12, 9 (1981).
2) N. Ishida et al.: submitted to Nucl. Instrum. Methods.
3) K. Masuda et al.: RIKEN Accel. Prog. Rep., 27, 116(1993).

RIKEN Accel. Prog. Rep. 28 (1995)

A Blow-in Type Windowless Gas Target
K. Sagara, A. Motoshima,* H. Akiyoshi,* N. Nishimori, and K. Maeda
A new-type windowless gas target has been designed
to produce a fairly thick target having a low gasconsumption rate. As shown in Fig. 1, the gas is blown
into a target cell from both the upstream and downstream ends of the cell (cylindrical sections of 6 mm
in diameter) through inclined narrow gaps. The gas
back-flowing out of the cylindrical sections is pumped
out by two mechanical booster pumps (MBPI-2) andby three turbo-molecular pumps (TMPI-3).

psi

P4

TMP1

TMP21

I I P2~
I I
):
p;
P3

P3

P4

MBP21

TMP1

~

beam

I

MBP2

I

MBP1~~
I

0

I

I

I

I

I

Scm

I

I

Ps

•
ITMP3

Fig. 1. A blow-in type windowless gas target. The
back-flowing gas is evacuated by two mechanicalbooster pumps (MBP) and three turbo-molecular
pumps (TMP). A blow-out gas target is realized by injecting the gas through the side wall at target center.

thicker than that of BOGT for the same gas flow rate, if
the gas distribution is the same in the both cases. The
gas pressure along the beam axis was measured using
the elastic scattering of protons at 90°. Figure 3 shows
clearly that BIGT has a desirable flat-top distribution
whereas BOGT has a gradually-dumping distribution.
The present pumping speeds of MBPI and MBP2
are 330 and 600 m 3 /hr, respectively, and that of each
TMP is 520 lis. For N2 gas, the maximum of thepressure pI is now limited to 1.6 kPa by the pumping
speed of TMPl. To increase pI for N2 (4He) up to 4 (2)kPa, some of the pumps need to be replaced by more
powerful ones. The effective target length is about 3
cm at present (see Fig. 3). It is easy to increase thelength up to, for example, 10 cm. The N2-gas thicknessof 4 kPa x 10 cm corresponds to 0.5 mgjcm 2.

E' 1.2c::::JN2 gas~.~ 0.8.D

In the differentially-pumped windowless gas targets l ) so far developed, the gas is blown out from thecenter of the target cell. The present blow-in gas target(BIGT) is superior to the previous blow-out gas target(BOGT) in confining the gas. Figure 2 shows thatthe gas (N 2) pressure at the target center, pI (see Fig.
1), of BIGT is about twice higher than pI of BOGT
when the pressure p2 (see Fig. 1) is the same. Thismeans that the target thickness of BIGT is about twice
0.'5.---~--~--~--~--~--~--~--.

---c... 0.'
CQ~

Blowout

N

c...

0

0.05

in

CO

8

Fig. 2. Gas pressure pI at the target center versus thepressure p2 at the first pumping section (see Fig. 1).

~ 0.6
CD

-+-Blow-in

~ 0.4

IIJ

- -0 - - Blow-out

~ 0.2

'Q

IIJ
(Il

Cl

0_

3

-2

-1

0

2

3

distance from the target center (em)Fig. 3. Target gas pressure along the beam axis.

From the present data, the gas-flow for BIGT of 4kPa N2 is estimated to be about 0.8 m 3 jhr, which isconsiderably less than the flow of 25 m 3 jhr necessary
for a N2-gas jet target of 0.5 mg/cm 2 in thickness. 2)
BIGT will be useful for low-energy experiments suchas in astro-nuclear physics, and for secondary-beamproduction with very high-intensity primary beams. It
also has a possibility to be used as a charge stripper
for intense heavy-ion beams.
References
1) J. Bussiere and J. M. Robson: Nucl. Instrum. Methods,
91, 103 (1971).
2) G. Bittner et al.: ibid. , 161, 1 (1979).

Department of Physics, Kyushu University

131

RIKEN Accel. Prog. Rep. 28 (1995)

Observation Program of Cosmic Ray Ions with
the First Brazillian Scientific Satellite
T. Kohno, T. Imai, H. Kato, 1. Yamagiwa, and K. Nagata
The first Brazillian scientific satellite is planned tobe launched on October 1996. We plan to promote a
joint experiment for cosmic ray observation in collaboration with University of Campinas (UNICAMP) andNational Institute of Space Research (INPE: Instituto
Nacional de Pesquisas Espaciais). The planned orbit
is a sun synchronous circular orbit with 800 km altitude and 99° inclination. This is a piggyback satelliteof a main remote sensing satellite. The total payload
is only 10 kg, and three or four instruments will be
accepted to be onboard. Because of the very severe
condition of weight , we concentrate our purpose on
the observation of elemental composition of anomalous
cosmic ray (ACR) where C - Ne will play an importantrole.
It is already confirmed that the ACRs are singly
ionized whereas the galactic cosmic rays (GCRs) are
fully stripped nuclei. Therefore the magnetic rigidityof ACR in the geomagnetic field is much greater thanthat of GCR in the same energy range. That means
ACRs can be observed at a low latitude where GCRs
cannot come from the outer space. This is a great
merit for a near earth orbiting satellite such as thiscase.
From our former experience,1) we know that elemental separation for medium nuclei (C,N,O,Ne) is possible even if we do not use position sensitive detectors
if we limit the acceptance angle (() in Fig. 1) withinsome limited value. We can save the electronic circuit
weight by omitting PSDs (reducing the number of signals). Shown in Fig. 1 is a cross sectional view of thetelescope. As shown here, we adopt a bidirectional entrance structure so that we can double the geometricfactor by adding only one more tl.E detector. Thismethod is usually very difficult to use because we haveto clear the field of view for two opposite directions.
But it is rather not so difficult in case of the satelliteof a very small size, one side of the satellite being not
too larger than the size of the telescope itself.
If we take the value of () to be very small, the par-ticle identification umbiguity due to pathlength distribution in the penetrating detector can be very small,that means good resolution. But we can get only a verysmall geometric factor, that means very small collecting power which leads to poor satistics. And if we takelarge (J, the resolution becomes bad vice versa. In order to obtain the optimum value of (J, we carried out
numerical simulations assuming isotropic entrance andcosmic ray abundance of elements. We show one of theresults of this simulation in Fig. 2. We decided (J tobe 25° from these results of simulation. The geometricfactor for this design is rv3 cm 2 . sr.

'......

20 deg200;:3 150
II)

Cl

..

100

".

N~

F
0

50

0

200
400
02 (Mev)

600

Fig. 2. One of the results of numerical simulation forthe particle separation ability of the telescope. Only
particles heavier than helium are originated. This is ascatter plot of energy losses in D1 vs. D2 for the events
stopped in D2 for the case of B = 20° . We can see thatthe elemental separation up to Ne is clearly possible.

The telescope consists of two thin tl.E detectors located at the front of both sides and five .&detectors
located at the midst of them (Fig. 1). The tl.E detector has an effective area of 48 mm x 48 mm and a
thickness of 0.25 mm. The .&detector has a size of 28mm x 28 mm and a thickness of 1 mm. The observable energy by this assembly is 14- 54 MeV/nucleon
forfor example. The total weight will be rv3 kg together with the telescope and electronics. We need tocarry out nuclear calibration of the whole instrument
by using heavy ion beams from RRC before launch.

°

01

02-06

07

Fig. 1. Cross sectional view of the telescope. Particles
coming in from both sides can be observed.

132

References
1) T. Kohno et al.: l. Phys. Soc. lpn. , 60, 3967 (1991).

RIKEN Accel. Prog. Rep. 28 (1995)

Collinear Resonance Ionization Spectrometerwith Diode and UV Lasers
M. Kubota,* H. Katsuragawa, T. Minowa,* and H. K. Uematsu**
In a past decade we have been developing ahighly sensitive detection method and efficient atomizers for metal elements in resonance ionization
spectroscopy. 1,2) As a next step we are constructing
a collinear resonance ionization spectrometer with adiode laser and a UV laser.
The experimental setup is shown in Fig. 1. A
collinear beam arrangement is employed because thisarrangement is capable of doppler tuning. A Li ion

beam sUJ?plied with a surface ion source is neutralized
in a charge exchange cell. The first step excitationof the resulting Li atomic beam is carried out with
a 670.8 nm diode laser which corresponds to the 282p transition of Li. The second step excitation of Li
atoms to ionization continuum is achieved with a N2
laser radiation (377.1 nm). In this manner Li atoms
are ionized again and a resonance ionization spectrumof Li can be observed by high-resolution diode lasers.

DIODE LASERCHARGE EXCHANGE CELLION SOURCE{DETECTOR~
Fig. 1. Schematic diagram of collinear resonance ionization spectrometer.

Now the surface-ionization ion source is running andthe maximum ion current of 200 nA has been attainedfor Ba. For Li the maximum ion current is estimatedto be a few nA. Neutralization of a Ba ion beam in the
charge exchange cell has been successfully performed.

References
1) T. Minowa et al.: Rev. Sci. Instrum., 60, 3280 (1989).
2) H. Katsuragawa et al.: ibid., 64, 265 (1993).

Faculty of Science, Toho University
Tokyo Gakugei University

133

RIKEN Accel. Prog. Rep . 28 (1995)

Design of Tritium Gas Handling System for Muon Catalyzed
Fusion Experiment at RIKEN-RAL Muon Facility
T. Matsuzaki, K. Ishida, 1. Watanabe, K. Nagamine, M. Kato,* K. Kurosawa,*
M. Hashimoto,* M. Tanase,* and H. Kudo**
For the muon catalyzed fusion (J-LCF) experiment at
RIKEN Muon Facility of Rutherford Appleton Laboratory in U. K. , a high purity D-T gas target , freefrom 3He component, is in preparation in order to perform precise measurements of a-sticking probability in
a J-LCF cycle. The 3He is a daughter nucleus of tritium(T) and does terminate the J-LCF cycle because a negative muon is captured by a doubly electrically charged

3He nucleus. For this J-LCF experiment, a tritium gas
handling system has been designed and is now underconstruction.
The proposed flow diagram and the inner layout of
the equipment are shown in Figs. 1 and 2. The gas
handling system is constructed in a glove box and contains the following equipments; a tritium gas cylinder,
a duterium gas cylinder, uranium getters, a palladium

HzO-'-l
AT _ L._He

Ii~~--------~~Ne

G6tD atock' - -_ _ _ _ _ _ _~_ _e_-+_'_tD.atock

T,1IIum
mlllitor

Fig. 1. Proposed flow diagram of the tritium gas handling system.

filter , a cryo-trap, a cryopump, titanium getters, aradio-gas chromatograph, a buffer tank of a constantvolume, buffer tanks, in-line tritium monitors , a glove
box tritium monitor , a turbo molecular pump, a dry
pump, a helium leak detector, and their control system. A tritium clean-up system employing ZrFe getters to circulate the glove box inner gas (Ar), which is
not shown in the figure , is connected to the glove box
for possible leakage of tritium gas.
The target gas purification is performed by utilizing
a uranium getter, a cryopump , a palladium filter anda cryo-trap. The radio-gas chromatograph includes an
ion chamber to make hydrogen isotope analysis.
The gas handling system is installed in RIKEN
Muon Facility and is directly connected to the J-LCF
target chamber, where gas purification to remove 3Hecomponent and formation of the D-T gas mixtures are
conducted at the experiment site.
Department of Radioisotopes, Japan Atomic Energy Research InstituteDepartment of Chemistry, Tohoku University

134

Fig. 2. Proposed layout of the equipment in glove box.

RIKEN Accel. Prog. Rep. 28 (1995)

Production Tests of Radioisotope Beam by
SLOW Beam Channel
T. Matsuzaki, R. Kadono, K. Ishida, A. Matsushita, and K. Nagamine
A low-energy radioisotope beam channel "SLOW"
has been developed at RIKEN Ring Cyclotron. The
main goal of this beam line was not only for the studyof emission mechanisms of various low-energy ions froma characterized metal surface of the primary target,
but also for the generation of radioactive ion beams forsurface-physics studies of the secondary target. The
detailed design, construction and performance are described in Ref. l.
After the various improvements of the beam line,2)
the test experiments were performed to produce radioactive ions from a tungsten metal surface by the
nuclear reactions using argon and nitrogen beams fromRRC.
For the primary target , two types of tungsten foil
were used; a foil with a thickness of 50 J.lm and a multifolded foil with an effective thickness of 500 J.lm (25J.lm x 20). The targets were directly heated up to 2000
K by introducing a DC current and were irradiated by
40 Ar beam (95 MeV I A) and 14N beam (135 MeV I A)
to observe the produced ions by nuclear reactions. The
vacuum at the targets was 10- 7 to 10- 8 torr during thebeam irradiation. In the experiment, hydrogen andoxygen gases were introduced to the target in order tochange the surface condition and then the produced
ion yields were measured.
In the obtained spectra, alkaline ions naturally existing at the target surface were clearly observed but any
significant signals of the ions associated with nuclear
reactions by the beam irradiation were not observed.
In the transmitting type target employed in thisexperiment, the nuclei which are originally producedby the' target fragmentation mechanism in thin target
materials were expected to be thermally diffused tothe surface to make surface ionization. The possibility of this process was proved to be very small in theexperiments. Another experiment using fully or partially beam stopping type targets should be conducted
to investigate the possibility of this process.
The production yield which is known experimentally
was found out to be much smaller compared with theE7 room background, even after the installation of aradiation shield around the detection point. The room
background was proved to be dominated by the components from the switching magnet and the beam dump
in E7. The best way to solve the problem is considered
to extend the SLOW beam line in order to transport
the produced ions to a low background area to determine the yields precisely. The detector should be also
modified to minimize the effective volume to improve
the SIN ratio.
From the technical point of view to produce radioactive beams more effectively, a major modification
might be required for the SLOW beam channel; theproduction part of radioactive nuclei and their ionization part should be separated like ISOLDE at CERN
where the ionization part is expected to contain various types of ionization device.
After some relevant modifications of the SLOW
beam channel, this experimental program will berestarted.
References
1) T. Matsuzaki et al.: Nucl. Instrum. Methods Phys. Rev.,
B70, 101 (1992).
2) T. Matsuzaki et al.: RIKEN Accel. Prog. Rep., 27, 112(1993).

135

RIKEN Accel. Prog. Rep. 28 (1995)

Construction of a Heat-Pipe Oven System for Laser Spectroscopyof Radioactive Isotopes
H. Maeda and F. Ambe
The heat-pipe oven was originally developed by Vidal and Cooper!) for the purpose of confining metal
vapors in an optical cell to perform a variety of spectroscopic measurements on metal atoms. The significant feature of this device is that a homogeneous vapor of well-defined temperature, pressure, and optical
path length can be generated and confined in a cell fora considerably long period of time without losing any
transparency of optical windows. Since temperature,pressure, and optical path length of the confined vapor can be controlled easily and measured accurately,
the heat-pipe oven is available for quantitative spectroscopic measurements of atoms. Also, to use this device
is advantageous for the detection and measurementsof an extremely small amount of atoms. This is because, firstly, atoms are confined inside of the cell and,secondly, the thermionic diode, an extremely sensitive
detector for ionized atoms, is optimally applicable. 2 ,3)It should be noted that the heat-pipe oven in conjunction with the thermionic-diode detector has also beena well established tool for high-resolution Doppler-free
spectroscopy of alkali-metal and alkaline-earth-metal
atoms. 4 )Recently, we have constructed a heat-pipe oven system to investigate radioactive isotopes, radioactive decays, nuclear reactions, etc., by the methods of laser
spectroscopy. There are many important experimentsthat will be possible if adequate numbers of radioactive atoms of interest are confined in an optical cellfor a sufficiently long time. One example is the laser
spectroscopy of nuclear decay fragments. 5 ) Employing
the heat-pipe oven in such experiments is very promising due to the several characteristic features describedabove.
Figure 1 shows the schematic diagram of our experimental setup. Briefly, it is composed of two pulsed
Ti:AI 2 0 3 lasers pumped by the second harmonic ofa Q-switched Nd:YAG laser with a maximum output
power of 200 mJ per pulse at 532 nm and repetition
rate of 10 Hz, a heat-pipe oven, and a data-acquisition
system which consists mainly of an amplifier, a gatedintegrator, and a personal computer. The Ti:AI 2 0 3
laser has a tuning range from 690 to 950 nm witha maximum power of about 20 mJ per pulse and alinewidth of less than 0.1 cm -1. A design of the heatpipe oven is basically similar to that described in Ref.
1. It is equipped with a 3.5-cm-inside-diameter, 90-cmlong stainless-steel tube which has a 5-cm-Iong glass
portion in the middle and optical windows at both136

ends. The tube is connected to a vacuum system sothat it is evacuated up to 10- 6 Torr and filled with
10- 2 - 10 Torr of He buffer gas. This buffer gas andwater coolings at both ends of the tube playa role toprevent the deposition of metal on the windows. The
tube is heated electrically up to about 650 K. For measuring and detecting spectral lines of atoms we employ
a photomultiplier as well as a thermionic diode ion detector. In particular, to activate the thermionic diodedetector a 0.5-mm-diameter tungsten wire is inserted
along the center of the tube and negatively biased (afew V) through a 100-kO load resistor. In this manner
the pipe acts as a diode with a tungsten wire being
the cathode and the wall of the pipe being the anode.
Then changes in the diode current due to ion formation is detected as voltage changes through a O.OI-J.LF
capacitor.

.-

H.-pipe Oven

C
----l

Wire ElectrodeR

CooIiDII-

Window

Wider\-BulrerGas
Inlet

To DHrusion Pump

Fig. 1. A schematic diagram of the experimental setup.

As a preliminary experiment we have successfully
observed the multi photon ionization spectrum of stable
133CS atoms. Application of the setup to investigate
the radioactive atoms is now under progress.
References
1) C. R. Vidal and J. Cooper: J. Appl. Phys., 40, 3370
(1969).
2) K. C. Harvey: Rev. Sci. Instrum., 52, 204 (1981).
3) D. C. Thompson and B. P. Stoicheff: ibid., 53, 822(1982).
4) See, for example, K. Niemax: Acta Phys. Pol. A, 61,
517 (1982).
5) See, for example, V. S. Letokhov: Laser Photoionization
Spectroscopy, Academic Press, Orlando, p. 106 (1988).

6. Material Analysis

RIKEN Accel. Prog. Rep. 28 (1995)

In situ Analysis of Liquid Samples by Vertical Beam PIXE
J. Kawai and K. Maeda
Particle-induced X-ray emission (PIXE) spectrometry has an advantage that it is sensitive to heavy metals
in a light element matrix such as liquid or biologicalsamples. Liquid samples are one of the good targets of
PIXE, and the beam should be vertical and the measurement should be carried out under a non-vacuum
condition.
We have constructed a vertical beam line at RILAC
for measuring PIXE of liquid samples. The horizontal ion beam was bent by a magnet, and came out
in air through aluminum exit foil (6 J.Lm) as shown in
Fig. 1. The details of the exit foil have been describedearlier. 1 ) The aluminum foil was insulated from groundlevel of the beam line to measure the current of ion
beam going through the foil. The detector used wasan Si(Li) solid state detector. The ion beam current
measured by a Faraday cup was 10- 100 nA/cm 2 for 8
MeV He+ in vacuum. The ion energy at the surfaceof liquid after traveling in aluminum foil and air was
estimated to be 20% lower than that of in vacuum.
The integral beam current was monitored by currents
induced in the aluminum foil and in the sample.

The samples measured were, (1) aqueous solutions ofvarious concentrations of Cu 2 +, Sr 2+, Ca2+, and Cr 3 +(30-10000 ppm) with N0 3 -, (2) milk, and (3) "Du
Zhong" tea (Tochuu-cha). The samples (2) and (3)were expected to have a high Ca2+ concentration. Recently in Japan, "Du Zhong" tea is one of the healthy
beverages. Representative measured spectra of samples (2) and (3) are shown in Fig. 2. The concentrations determined from the calibration curve madeby the aqueous solutions of various concentrations of
Cu 2+, Sr 2+, Ca2+, and Cr3 + ions were Ca2 + 1100 ppm(nominal, 1000 ppm), K+ 890 ppm, and CI- 250 ppm
for milk, and Ca 2+ 70 ppm for Du Zhong tea.

X-ray energy (keV)

0
5
1111
4

1111
3
1111
a;C

I
C
J

-f

2

1111
1
1111
III

8 1111

Ground floor
Underground

5
1111

~

3

X t8
Faraday cup

~

. ..

~~~= screen
FluorescentAr

S.E 11114
i;-

2
t8
1
18

;~

i ~Ca
_

)

VV

DuZhongtea

i
\01'

.~=.
......... :''''J',:'.~",,:;-::.,

8
1111

Channel number
Fig. 2. Representative PIXE spectra of milk and "DuZhong" tea.

References
Fig. 1. Schematic illustration of the experimental setup.

1) Y. Sasa, K. Maeda, and M. Uda: RIKEN Accel. Prog.
Rep., 24, 127 (1990).

137

RIKEN Accel. Prog. Rep. 28 (1995)

X-ray Satellite Caused by Radiative Auger Effect
K. Maeda and J. Kawai
In highly-sensitive element analysis by X-ray spectrometry, satellite X-rays often obstruct the detectionof trace elements. We have reported low-energy satellites accompanying the main Ka line in X-ray spectra
excited by He-ion (8 MeV) impact. I) In this report,
measurements of the same satellites excited by an Xray tube are reported.
Samples were high purity metallic Ti, V, Fe, Cu,
and Zr, and powders of CaF 2 , Ti0 2 , and RbF. X-ray
spectra were measured with a conventional X-ray fluorescence (XRF) spectrometer of Bragg type [Rh anodetube (30 kV and 10-40 rnA) and Ge(lll) or LiF(200)analyzing crystal].
Representative XRF spectra are shown in Fig. 1
along with the spectrum obtained by the He-ion impact. A weak broad peak was observed in the energy
region corresponding to K-LL Auger transitions in allthese spectra. The energies and intensities of the peakrelative to the Ka line measured by the three different
procedures were almost the same. From the peak en-

X1o-3
2.0

. x1000

VK·Ll' .. ',: . ..,

escapepeak ot

VKIl

0.8

Z Element Sample Excitation
X-ray
Integrated
spectrometersourceintensity (%)
20
Ca
C aF 2 Rh X-rays Ge crystala)-PC b ) 0.09±0.01
He ions0.17±0.03
Si(Li) SSD

1.6 :.

.'

1.2,........

0.4
VK~

He2+ impact
Si(Li) detector

'.
X1o-3

e

Table 1. Relative intensity of the K-LL RAE satellite tothat of the Kal,2 line .

:. VKa~':..

ergy, intensity and spectral shape, these peaks were
attributed to the K-LL RAE (radiative Auger effect)satellites.
The K-LL RAE satellite was found in all spectra
measured here. The intensities of the RAE satellites
are summarized in Table 1 with the reproducibility(standard deviation) of the measurements. The dataobtained by the He-ion impact is also given in the table. The integrated intensity was estimated after subtracting the background and correcting the matrix effects and detection efficiency. The range of integration was fixed to be twice of the energy separation
between the highest p 2 K-L3L3) and lowest eSo KLILI) Auger energies. The K-LL RAE/Ka intensity
ratio was between 0.05-0.2% for elements of atomic
number Z = 20-40. This means that neglect of the
K-LL RAE satellites will introduce a serious error intrace analysis. There was no significant difference in
the intensity ratio due to the differences of chemical
species and excitation methods.

x1000

22

Ti

Ti
Ti02
Ti
Ti02

Rh X-rays Ge crystal-PC
Rh X-rays Ge crystal-PC
Rh X-rays 'LiF crystalc)-pC
Rh X-rays LiF crystal-PC

0.20±0.05
0.17±0.03
0.22±0.02
0.19±0.02

i

23

V

V

I

Rh X-rays Ge crystal-PC
Rh X-rays LiF crystal-PC
He ions
Si(Li) SSD

0.19±0.03
0.23±0.03
0.20±O.O4

24

Cr

Cr

He ions

Si(Li) SSD

0.12±0.02

25

Mn

Mn

He ions

Si(Li) SSD

0.08±0.O2

26

Fe

Fe

Rh X-rays LiF crystal-PC
He ions
Si(Li) SSD

O.O5±O.Ol
0.07±0.Ol·/·········0

VKa

~

1.0

0.8

~

!

0.4
Rh X-ray tube
Bragg spectrometer

VKj}

i

Ge(111)
0.2

0.8

0.4
VK~

0
4.0

4.5

5.0

5.5

X-ray energy (keV)

Fig. 1. X-ray spectra in the low-energy region of V Ka
obtained from vanadium metal. L X-rays of Sn wereconsidered to be emitted from the sample holder.

138

29

Cu

Cu

Rh X-rays LiF crystal-PC

0.20±0.Ol

37

Rb

RbF Rh X-rays LiF crystal-PC

0.05±0.01

40

Zr

Zr

0.05±0.01

Rh X-rays LiF crystal-PCa) Bragg spectrometer with a flat Ge(111) analyzing crystal.
b) proportional counter.
c) Bragg spectrometer with a flat LiF(200) analyzing crystal.

References
1) K. Maeda and J. Kawai: RIKEN Accel. Prog. Rep., 26,
130 (1992).

RIKEN Accel. Prog. Rep. 28 (1995)

Analysis of Trace Elements in Fish Otoliths by In-Air PIXE
N. Arai,* w. Sakamoto,* and K. Maeda
Fish otoliths in the inner ear detect or control theacceleration and position of the fish and are composedof a calcium carbonate-protein or calcium-phosphateprotein matrix as a needle aragonite crystal. Thace
elements in the otoliths were known to be a good indicator of ambient environment. Many studies havebeen therefore carried out using SEM-EDX or SEMWDX. Gunn et aLl) reviewed these analytical techniques and reported that EDX systems were not suitable for quantitative analysis of trace elements «5000ppm) in otoliths and WDX systems were able to measure elements such as Ca, Na, Sr, K, S, and CI to levelsof several hundreds ppm, but the analyses damaged
specimens and caused pitting and chemical change.
We adopted in-air PIXE (Particle Induced X-ray Emission) in trace elements analysis of otoliths from several
species of teleost fish.
Otoliths were removed from juvenile red sea bream,
Pagrus major, and rockfish, Sebastes schlegeli. The red
sea breams were reared in three different sea-farming
stations, Momoshima (MS) and Hakatajima (HT) in
the Seto Inland Sea and Miyazu (MZ) in the Sea ofJapan. Two different origins of rockfish were examined; one was reared in Miyako sea-farming stationand the other was caught in Miyako Bay in I wate Prefecture. Otoliths surfaces were not cut nor polishedand bombarded in air by a 1.6 MeV proton beam generated in the Tandetron accelerator of RIKEN. Twotypes of graphite collimators, 1- and 3-mm in diameter, were used in order to regulate the spot size of the
proton beam. These collimators were insulated froman aluminum exit nozzle using a polyethylene sheet.
The proton beam was brought out from the vacuum
system .into air through a 6-J.Lm thick Al foil, and traveled 10-mm in air to the target. Path lengths in air
and the Al foil caused a reduction in the proton energy from 1.6 MeV down to 1.16 MeV and spread thebeam spot to diameter of about 1.2 mm. The beam
intensity was monitored by collecting charge from the
Al foil. X-rays emitted from the target were detectedwith a lithium-drifted silicon, Si(Li), made by EG&G
Co. through a 74-J.Lm Al absorber in order to attenuate X-ray intensities of CaKa and CaK,8 and an 8J.Lm thick beryllium window. The distance was 19 mm
between the top of the Si(Li) crystal and the beam
spot on the target. The detector position was kept
at 135° with respect to the incident beam direction.
PIXE spectra were measured by monitoring a beam
current and accumulated for a total beam charge of
10- 20 J.LC. The PIXE spectral intensities were analyzed

after subtracting background by means of the computer program BATTY in PIXAN. 2) Concentrationsof trace elements in the otoliths were estimated withthe aids of theoretical X-ray yield calculated by thecomputer program THICK in PIXAN. Experimental
errors were examined by using standard argillaceous
SRM-1C certified by the NIST.
Table 1 shows concentrations of trace elements inotoliths from red sea bream. 3 ) There is a significant
difference between concentrations of Sr (P < 0.0001)
and Zn (P < 0.01). This difference appears due toambient seawater temperatures, I.e. MS: 26.6 °C, HT:
22.0 °C and MZ: 22.7 °C. Table 2 shows concentrationsof trace elements in the rockfish otoliths. There is aclear difference between reared fish Sr concentrations
and wild ones (P < 0.001). Although we have no direct environmental data to explain this difference, it isimportant that we can distinguish artificial fish fromwild fish by means of the analysis.

Table 1. Number of specimens and mean trace element
concentrations in otoliths from red sea bream reared inthree stations, ppm ± s.e. 3 )Station
MS
HT
MZ
a)

Zn a )
Sr a )N
Mn
Fe
29 2332±41 248±35 68±12 128±15
27 1752±32 194±31 60±6.6 65±9.5
36 1635±32 170±14 43±4.9 103±10

Kruskal-Wallis test, Sr: P < 0.0001, Zn: P < 0.01.

Table 2. Number of specimens and mean trace element
concentrations in wild rockfish otoliths and reared ones,
ppm ± s.e.
Sra )
Fe
Mn
Zn
N
Wild 19 1719±44 63±15 9±1.5 45±6.4
Reared 13 1547±36 41±7.4 9±1.9 36±5.9a) Student's t-test, p < 0.001.

References
1) J. S. Gunn, 1. R. Harrowfield, C. H. Proctor, and R. E.
Thresher: J. Exp. Mar. Biol. Ecol., 158, 1 (1992).
2) E. Clayton: PIXAN: The Lucas Heights PIXE Analysis
Computer Package, AAEC/M113 (1986).
3) N. Arai, W. Sakamoto, and K. Maeda: Fisheries Science, 61, 43 (1995).

Faculty of Agriculture, Kyoto University

139

RIKEN Accel. Prog. Rep. 28 (1995)

Microstructure and Chemical Composition of
Duckbilled Dinosaur Eggshell
K. Tazaki,*1 M. Aratani, S. Noda,*2 P. J. Currie,*3 and W. S. Fyfe*4
A dinosaur eggshell with preserved embryonic bones
has provided a clear record of micro-structure, mineralogy and chemistry of the eggshell. Six fragmentsof a duckbilled dinosaur eggshell collected from Alberta, Canada, were analyzed using X-ray powder
diffraction, a scanning electron microscope (SEM),
an energy dispersive analyzer, a transmission electron microscope (TEM), and heavy-ion probe Rutherford scattering. 1) Radial and tangential thin sectionsof two shell specimens showed two layers which weremainly composed of calcite with traces of apatite andaragonite. Silicate and iron oxides were also precipitated on outer surfaces, whereas apatite was precipitated between the two layers by diagenesis (Fig.
1). The presence of Fe, Cu, and Zn, detected byenergy dis-persive analysis, suggests the presence ofhematite, goethite, pyrite and Cu-Zn oxides whichwere a result of fossilization. Under the SEM , structural eggshell morphotype shows characteristic features of hadrosaurs, including irregular pore canals,
columns, and crescent-shaped mammillary layers andcones. The outer surfaces of the shells show the typicalcolumnar structure with pore openings. The organic
material on the inner surface of the eggshell showing amesh-like structure is interpreted as a fossilized membrane (chorion) of the eggshell. This would be thefirst record of such a delicate fine structure. Mosaic
and lamellar deformation features of calcite show 3.85
A(102) lattice images, apparent from high-resolution
TEM. Rutherford scattering analysis reveals that theeggshell contains C, 0, Si, Ca, Fe, and some heavy
elements, together with a trace of iridium.2) The presence of iridium and the pathological repetition of lay-

*1 Department of Earth Sciences, Kanazawa University
*2

*3
*4

140

Institute of Industrial Science and Technology, ShimaneRoyal Tyrrell Museum of Paleontology, Canada
Department of Earth Sciences, University of Western Ontario, Canada

Outer surface

f\:'i~"::::./-·:: ~':>:::.::. :: .~.i__-.-=~;;:::!~~
:,

:

;'

r

'

,.

",

~ :.

'

......
. . ..

~.

(

Ca'"

':,-J

... ..:.~~ ..:~~::.

Inner surface_----.e:=------'
IntenSity

Fig. 1. EDX line scanning analyses of the dinosaur
eggshell sample 2; RTMP 87.79.85 at line A-B. HighSi with Fe elements concentrated on outer surface,whereas high P with Ca elements concentrated between
two layers.

ers of Hadrosauria's eggshell may suggest that gradual environmental changes adversely affected the reproductive process.

References
1) K. Tazaki, M. Aratani, S. Noda, P. J. Currie, and W.
S. Fyfe: Sci. Rep. Kanazawa Univ., 39, 17 (1994).
2) M. Aratani and M. Yanokura: RIKEN Rev., No.4, p.
39 (1994).

RIKEN Accel. Prog. Rep. 28 (1995)

Heavy-ion Rutherford Scattering Applied to
the Investigation of Fire Causes
K. Sato, H. Honda,* J. Ushimaru,* M. Yanokura, K. Maeda, and M. Aratani
Heavy-ion Rutherford Scattering (HIRS) has been
applied to the investigation of fire causes. 1-3) The
Tokyo Fire Department performs a thorough investigation for decision of fire causes. Recently, fires causedby one-push igniter types of gas tables have increasedin number, and occupied ranks within the upper third
in the Tokyo Metropolis.
Usually, we observe soot deposited on the surface ofa brass rod for ignition of the gas table with microscope
to decide whether gas has been burned or not before
the fire. But, this method is not advantageous, becauseeven soot might have been burned by fire in cases above
a certain scale.
Thus we have employed the HIRS as an available
method. The HIRS method enables us to decide
whether the gas table has caused fire or not, depending on the distribution of oxygen atoms in the surface
layer of the brass rod. The rod is equipped in the gas
control valve and has a diameter of 3 mm and a lengthof 39.5 mm.
A 50 MeV Ar6 + beam of about 250 nA was used
as incident particles. The beam size was 0.2 mm x
2 mm. We set a sample holder with the brass rod
on the center of a scattering chamber, and a slit was
located in front of the sample holder. Detector A for
recoiled hydrogen, oxygen and carbon ions was locatedat 30° to the incident argon ion beam. Detector B for
scatterd argon ions was set at 40° (Fig. 1).

......l

i:LI
Z

Z

-<:

:r:
u

"(/)

E-<
Z
:::l

o

u

CHANNEL NUMBER
Fig. 2. Spectra for a standard sample prepared by an
artificial fire.

1. 0 00 0.0 - 3 . 1 (6 3 . 1-1 . 4 (
(
11-15
(

E

<> 1 . 4 - 11

o

Beam

Dete~:·~~;:;··~···~;·;~·····~········
D{~

\

350mm

x 10 " " m ) ,

O. 50
o

E

0,00 ~~~~~~~~~~~~~~~

0, 0 0Targetx 10"". )x 10"". )x 10" " . )

8

=

30'

A~B6
""":----C

10 , 02 O. 0(m m)

Fig. 3. Oxygen atom distribution in the surface layer of abrass rod.

and C, and they corresponded to the three regions on
the brass sample.
References

Fig. 1. Experimental apparatus.

Figure 2 was obtained with the gas table (in use
before fire) that was subjected to an artificial fire.
The spectra are able to be transferred to the ratioof oxygen atoms to zinc and copper atoms (Fig. 3).
Oxygen contents were graded into three levels, A, B,

1) K. Sato, H. Honda, J. Ushimaru, M. Yanokura, and M.
Aratani: Proc. May Meet. Jpn. Fire Soc., p. 62 (1994).
2) K . Sato, H. Honda, J. Ushimaru, M. Yanokura, and M.
Aratani: Proc. 38th Symp. Radiochem., p. 157 (1994).
3) K. Sato, H. Honda, J. Ushimaru, M. Yanokura, and M.
Aratani: Proc. 48th Conf. Natl. Fire Engineer, p. 47(1994).

Tokyo Fire Department
141

RIKEN Accel. Prog. Rep. 28 (1995)

RBS Study of Tb-Implanted Sapphire (I)M. Kumagai and M. Iwaki
A study has been made of the luminescence during
Tb-implantation in Ab03. The substrates used werecolorless and transparent single-crystal Al 2 0 3 withthe (1- 102) surface. The surfaces of all wafers weremechanically polished before ion implantation. The
Tb+ ion implantation was performed at an energy of
100 keV with fluences between 1 x 10 13 and 1 x 10 17
Tb/cm 2 at room temperature. The beam current density was about 0.05 J-LA/cm 2 . The luminescence owing
to Tb 3+ from Tb-implanted Al 2 0 3 was seen during
Tb-implantation.
In order to clarify the mechanism of ion beam induced luminescence of Tb-implanted A1 2 0 3, the composition, damage and Tb-Iattice sites in the Tbimplanted layers of Al 2 0 3 have been estimated by
Rutherford backscattering spectroscopy (RBS). RBS
spectra have been measured at room temperature byusing 1.5 MeV He+ ions with a scattering angle of 150
Figure 1 shows the spectra obtained at an approximately random direction of an implanted specimen
with 3.5 x 10 16 Tb/cm 2 . The depth profile of implanted
Tb+ showed a Gaussian-type distribution. The Tbdose calculated from the spectra is in good agreementwith the nominal value of the implanted dose. The
0

•

142

en 10000

.....

C
::l

,.

a

u

8000

3.5xlO2

Tb / emTb

Random+.......
0
-.J

~

6000

>-

o

Cll

~

a:
w

+

4000

<{

u

AI

+

ff-

2000

(fJ

::,,:

u

<{
(D

0
0.0

1.0

0.5

1.5

ENERGY / MeV

Fig. 1. Random spectra obtained for Ab03 with 3.5 x 10 16
Tb/cm 2 .

standard deviation calculat from the FWHM of the
Tb spectra is about 21.1 nm, which disagrees with thepredicted value of about 6.2 nm by the TRIM-90 code.
The depth corresponding to the Tb peak in the spectra
is about 19.6 nm, which shows a smaller value than the
projected range of Tb of about 23.4 nm predicted fromthe TRIM calculation.

7. Miscellaneous

RIKEN Accel. Prog. Rep. 28 (1995)

Design of a Moisture Monitor Based on H-D Exchange
in a Glass Surface Layer
T. Nozaki,* T. Kobayashi,* M. Aratani,** and M. Yanokura
Using heavy-ion ERDA and RBS, we formerly studied on the cation-by-hydrogen replacement in glass surface layers (less than a few micrometer thickness) andon the H-D exchange in them. The rates of the tworeactions were highly dependent on the glass composition, and the exchange for some soda-lime silicate glass
was found to be very slow at room temperature but almost completed in an hour at 80 DC.!) Based on theseresults, we have designed a time-integration monitor
unit for moisture in dry soils; it is shown in Fig. 1. Achip of the deuterium-replaced soda-lime glass , a cropof a highly soluble salt (e.g., LiCI, CaCI 2 , KI, or NaBr),
and a known, small amount of D 2 0 are contained in asmall box (e.g. , 1.5 cm diameter, 2 cm height) with awindow of a porous membrane.
Tight CapI~

POf"(JU' MemhraneProtect ion j\ rt............................+...........

Fig. 1. A monitor unit for moisture vapour pressure in
the soil.

Let us first assume that (1) the temperature and the
moisture vapour pressure outside are constant, (2) thepermeation constant through the film , I, is the samefor H 2 0 and D 2 0 vapours, and the permeation is slow
enough as compared with the time for the entering
H 2 0 to mix with the D 2 0 and for the outgoing D 2 0 to
diffuse away. Then we can set up a pair of simultaneous
differential equations,-d[D]/dt
I Vin[D]/([H] + [DJ) ,d[H]/dt(1)
I V out - I Vin[H]/([H] + [D]) ,where [D] and [H] are the quantities of D and H as water in the box, and Yin and V out are the water vapour
pressures inside and outside of the box, respectively.
Equations (1) can be solved easily, and give the relation,[H]/[D] = {I + (R - l)tlr }R/(R-l) - 1,
(2)
where R = Vout/V in and r = ([H] + [DJ)/I Yin' Figure
2 shows the relationship between [H]/[D] and R forsome values of tlr. Fairly linear dependence is seen of[H]/[D] on R and tiT, for [H]/ [D] < 0.3 and T < 0.5.
**

School of Hygienic Sciences, Kitasato University
Institute for Environmental Sciences

2.5,------------,

1.5.....,0,.7

~~:.:
0.5

1.5

R

Fig. 2. Dependence of HID ratio in the monitor box on
the moisture vapour pressure and exposure time. For
Rand r, see text.

The value of I can be obtained from the weight gainof well dried molecular sieves separated by the membrane from an atmosphere of a saturated salt solution.
For a given I, T and R can be varied by selecting thesalt and the quantity of initial D 2 0. Now, ultrafiltration membranes of various characteristics are commercially available. A disposable set of ultrafiltration under centrifugation consisting of a tiny box with themembrane can be used for our set with little modification. After being exposed to the environment, themonitor box is capped tightly and kept at 80 DC for
an hour. The [H] I [D] ratio in the glass surface is thenmeasured by ERDA. The ERDA spectrum for Hand D
of uniform distributions can be obtained as rectangles
under a measurement condition close to the condition
we have used for a long time. From such spectra, we
can obtain the [H]/[D] value easily and reliably. A
value between 0.05 to. 0.25 is suitable for the measurement, owing to the higher sensitivity of H than D in
ERDA.
The effect of temperature change in practical use is
not so serious, because the temperature changes lessin the soil than its outside and because I for a realgas is proportional to the 0.6th to O.8th power of temperature. Also, a saturated solution of any salt, being
attached under the cap, can be used as a reference sample for the monitoring. The vapour pressure in the soilof desert lands often seems to be given by a saturated
solution of some salt.
There are other possible uses of deuterated glasses
for moisture monitoring. For example, a bare chipof deuterated Pyrex glass might be used for moisture minotoring at a high temperature range (150 to
230 DC).2)
References
1) T. Nozaki et al.: Heavy Ion Accel. Syst. Sci. Rep. (Tokyo
Inst. Tech.), 5, 50 (1990).
2) T. Kobayashi et al.: RIKEN Accel. Prog. Rep., 27, 100(1994).

143

IV. NUCLEAR DATARIKEN Accel. Prog. Rep. 28 (1995)

Status Report of the Nuclear Data Group
Y. Tendow, A. Yoshida, Y. Ohkubo, A. Hashizume, and K. Kitao
The Nuclear Data Group has 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. At the launching point of our groupin 1983, the scope of compilation was confined to the
nuclear reaction cross sections to produce only 20 radioisotopes commonly used in biomedical fields including He, 13N, 15 0, 18F, 28Mg, 52Fe, 67 Ga, 68Ge, 74 As,
77Br, 82Br, 77Kr, 81 Rb, 82mRb, 111 In, 123Xe, 127Xe,
123 1, 124 1, and 1251. We have afterward widened therange of radioisotopes to some extent and also started
to search comparatively important data not yet contained in the EXFOR master file until that time.
A considerable amount of old data not included in
the EXFOR master as well as the data appeared inrecent journals have been picked up and stocked in aqueue library and the compilation is in progress at thesame time.
(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 = 120 mass chain is now in progress.
A = 129 evaluation has come back from the review at
NNDC and is now in post-review by us. Mass chainsA = 127 and 118 are now in the stage of review at
NNDC.
The Table of Isotopes (8th edition) is scheduled tobe published by LBL and a draft of the part A = 118
through 129 has been sent from them for a pre-review
by the Japanese group.
(3) Nuclear Structure Reference file (NSR)
We are engaged in collecting and compiling secondary references (annual reports, conference proceedings, etc.) appeared in Japan since the previous year
into the Nuclear Structure Reference (NSR) file andsending it to NNDC.

The compilation of 1993 annual reports has been
completed and sent to NNDC. Secondary sources surveyed this year are the following annual reports (incode name in NSR); RIKEN (RIKEN Aceel. Prog.
Rep.), JAERI-TV (JAERI Tandem & V.D.G.), INS(INS Univ. Tokyo) , UTTAC (Univ. Tsukuba Tandem
Aeeel. Center), RCNP (Res. Center Nucl. Phys., Osaka Univ.) , OULNS (Osaka Univ. Lab. Nucl. Study),
and CYRIC (Cyclo. Radioisot. Center, Tohoku Univ.).
(4) Others
The IAEA Advisory Group Meeting on the Coordination of the Nuclear Data Centers was held at theOECD Nuclear Energy Agency in Paris on 25-27 April
1994. A proposal for restructuring of the going cooperation network was made at the meeting and another Special Meeting was given at NDS IAEA on 31
October- 1 November to discuss and adopt a new agreement for the general restructuring of the international
nuclear data cooperation.
Recent developments in performance of desktop PC
and peripheral storage equipments should bring revolutionary improvements in the use of nuclear data as wellas in the evaluation or compilation methods of thesedata bases. Whole ENSDF data base, along with the
NSR files, the Table of Isotopes (8th edition) and otherspecial data bases such as Evaluated High-Spin Data
File (EHSDF) , Evaluated Nuclear Chart Data File
(ENCDF) etc. are going to be disseminated in a single
CD-ROM disk. The disk should also include softwares
which provide interactive access to them literally, numerically and graphically on PC's with Macintosh,
Windows or UNIX platform. Because of the rapidly
increasing quantity of information, nuclear data are tobe published more and more on electronic media suchas CD-ROM from now onwards.
References
1) Y . Tendow, A. Yoshida, Y. Ohkubo, A. Hashizume, andK. Kitao: RIKEN Aeeel. Prog. Rep., 27, 127 (1994).

145

RIKEN Accel. Prog. Rep. 28 (1995)

Evaluation of Nuclear Structure Data of A=120
A. Hashizume, * K. Kitao, and Y. Tendow
The experimental nuclear data concerning the mass
number 120 have been collected and evaluation wasmade so as to obtain a reliable new data-set file. The
last evaluation was published in 1987. 1) The cut-off
date of data collections of this publication was march
1986. This evaluation was made for the data collectedfrom 205 references cited therin. Since then, 62 studies
were reported to the end of 1993. The new file is arevised edition of the old one.
The file is consisted of 4 new data-sets, 17 revised
data-sets and 44 data-sets which remained essentiallyunchanged. The new data-sets are the adopted levels
in 120Pd,120Pd ,B-decay and 238U(1Li,f). Here a dataset means a set of data for an adopted level, a decay or
a reaction defined by incident and outgoing particles.
After the compilation of data, the evaluation was
made. For example, ,-ray data were tested by Rits'rule and intensity balance. Energies of excited states
were obtained from the least-squares analysis. Spinsand parities of states proposed by authors are testedby the log-ft in case of ,B-decay. In the course of evaluation, a group of computer programmes which arecommonly used in mass chain evaluators in the world
was generated to make and to check the data-sets.
The changes common for all new data-sets are following.
(1) Because new mass evaluation has been made by
Audi and Wapstra in 1993, the Q-values of decays, ,Bray energies and log-ft values were changed.
(2) The values of Ref. 2 were generally adopted for
dipole- and quadrupole-moments because systematic
corrections were applied to the original data.
(3) The cross-references were made for adopted dataso as to make clear the correspondence to each data-set
follwoing a new rule to make the file.
Figure 1 shows, for an example, a comparison ofstates in 120Te followed by 120 1 decay for old and new
files.

Japan Atomic Energy Relations Organization

146

MeV
4

>.

bO

3

1

0-------------old rile

new rile

Fig. 1. The states in 12~Te excited by 120ln decay.

References
1) A. Hashizume and Y. Tendow: Nucl. Data Sheets, 52,

641 (1987) .
2) P. Raghavan:(1989).

At. Data Nucl. Data Tables, 43, 189

V.

DEVELOPMENT OF ACCELERATOR FACILITIESRIKEN Accel. Prog. Rep. 28 (1995)

Status of RIKEN 10 GHz Electron Cyclotron
Resonance Ion Source (ECRIS)
T. Nakagawa, T. Kageyama, M. Kase, A. Goto, and Y. Yano
Recently, we modified the RIKEN 10 GHz ECRIS
by introducing so-called plasma cathode method to thefirst stage structure to increase the beam intensity ofhighly charged ions from gaseous elements 1) In thispaper, we report the effect of this method to produce
the highly charged ions from solid materials.
To produce the ions from solid materials, ceramicrods were inserted into the plasma regions through an
open space between poles of a sextuple magnet in thesecond stage and heated to obtain the sufficient vapor
pressure. The supporting rod for a solid material wascooled by the water to prevent the temperature risingof the supporting rod. In the case of MgO , A1 2 0 3 , andZrO, the diameter and length were 4 and 200 mm, respectively. The NiO rod was rectangular prism witha base 4 mm x 4 mm and a length of 40 mm. The
gas pressures of the first, second, and extraction stages
were 1.0 x 10- 5 , 5 X 10- 7, and 8 x 10- 8 Torrs, respectively. The RF power of the second stage was about
500 W. Extracted voltage was 10 kV. Under this condition, we obtained the average beam intensity of 80
eJ-LA for Af+ ions. Maximum current of A17+ was
100 eJ-LA for short time. This value was about threetimes as high as that without using the plasma cathodemethod. The consumption rate of the rod was about
0.01 mm/min. Figure 1 shows beam intensities of thehighly charged Mg, AI, Ni, and Zr ions for each charge
state. Closed and open circles are with and without
using plasma cathode method. The beam intensity
was strongly enhanced by using it. The beam intensity of A18+ ions increased from 15 to 60 eJ-LA . In thecase of the Ni 18+, beam intensity increased from 4 to
12 eJ-LA: The beam intensity of Mg ions was relatively

100

~c

.r:;;
c::

10

B

.5

E
~
C1)

~

6

8

Charge State

Fig. 1. Charge state distributions of Mg, AI, Ni, and Zr
ions. Closed and Open circles are the beam intensitywith and without using the plasma cahtode method.

lower than those of Al ions. The melting temperatureof MgO is about 2800 DC, which is higher than that of
Al 2 0 3 (about 2000 DC). It seems that the temperatureand density of electrons are still not enough to obtain
the intense beam of highly charged ions produced fromthe solid materials having a higher melting temperatures such as MgO.
References
1) T. Nakagawa, T. Kageyama, M. Kase, A. Goto, and Y.
Yano: Jpn. J. Appl. Phys., 32, 1335 (1993).

147

RIKEN Accel. Prog. Rep. 28 (1995)

Status of the RIKEN Polarized Ion Source
H. Okamura, N. Sakamoto, T. Uesaka, H. Sakai, K. Hatanaka, K. Ikegami, J. Fujita,
M. Kase, A. Goto, and Y. Yano
An important progress of the ion source development in this year is the improvement of the polarization degree. The present level of the polarization issummarized in Table 1.
Table 1. Summary of polarization.
pure vector
Theor·1
value

pz

pzz

+~

2
--g

0

0

States at SX#I-exit
SFT#1
WFT#1
States at SX#2-exit
1,2,3
3-+6
SFT#2
WFT#2
States at ECR

I pz
pzz
pz
Previous I
Present
value
value

pzz

pure Jz

pure tensor
0
+1

0
-2

0
+1

-1
+1

+1
+1

100

1,2,3
2-+6
1-+4 1-+42 ,32,32-+6 a ) 3-+5 a )

3-+5

1,3

1,2
2-+6

........
Vl
Vl
~

~

1,2,6 2,3,4

3,6

1-+4
2-+3
3 ,4

+0.57 -0 .55+0.76 -0.61+0.77 - 1.23 +0.58 +0 .67 +0.46 c )

l=:

1-+4

b)

2 ,5

1,3

+0.40 -0.43
b)

-

-0.92

-

1,6

90

;:::I

+0.49 -0.45+0.45 +0.39 c )a) Transitions 2-+6 and 3-+5 for the SFT#2 are switched by peri-

odically changing the magnetic field while the frequency of thegenerator is kept constant.
b) The input power to the WFT#2 cavity is set to less than 0 .4 W
to keep pzz negligibly small.
c) pzz increases as increasing the input power to the WFT#2 cavity
and reaches a maximum at the power greater than 1 W.

The possible sources causing the polarization reduction are: (1) a relatively strong radial component of
the ECR magnetic field; (2) insufficient pumping of
the ECR plasma region; (3) low efficiency of the RFtransitions; and (4) insufficient dissociation degree ofthe dissociator.
Concerning the ECR ionizer, the radial componentof the magnetic field has been reduced by increasing
the inner diameter of the sextupole magnet from 90
mm to 120 mm. This resulted in the decrease of the
field gradient from 122 Gauss/cm 2 to 53 Gauss/cm 2 .
It should be noted that the axial field is typically 800
Gauss at the plasma region to meet the ECR condition(Eo = 874 Gauss) for the 2.45-GHz micro wave.
While the reduced radial field will minimize the influence of the transverse components on the polarization, the increase of the diameter of ionizing region,
which is significantly larger than the atomic beam
diameter, will cause an increase of the unpolarizedbackground. Expecting the improved pumping of theplasma region, the diameter of the plasma chamber
has been increased from 70 mm to 110 mm. Also a
Ti sublimation pump has been installed in addit~onto the previously installed Ti-pump and the cryogenic
pump, yielding the total pumping speed of 4000 f/s forhydrogen.
Concerning the RF transition units, the magnet sys148

tern with tapered- and background-coils has been introduced so that the optimum gradient and strengthof the magnetic field can be obtained. A typical field
distribution is shown in Fig. 1. The dependence of thepolarization on the magnetic field has been carefully
studied as well as the dependence on the RF power fed
to the cavity (see footnotes of Table 1).

80

..c:
~

Trim
Field
Current Gradient(A) (Gauss/em)

tID

Q)

70

s...
......
CI)

'"C

Q)

+

60

X

50

0

t;:

0

1.0
0 .8
0 .6

2 .7

60

80

4.9
3.7

no

40

0

20

40

100

Relative Position (mm)Fig. 1. Magnetic field distribution of the SFT#2.

Although the polarization degree is satisfactorily
good in most cases, relatively low polarization is observed for the mode using the SFT#l. This is probably
attributed to the low efficiency of the first sextupole
magnet (SX#l) in selecting the spin-up states of theelectron. At present, the pure-Jz modes are not practically used for the experiment.
Concerning the dissociator, we tried to extract the
dissociation degree by measuring the D / D 2 - ratio of theatomic beam with the QMA. But the recombination
rate in the QMA-chamber, which causes an uncertainty
in the dissociation degree, was found to be significantly
large. Instead, the performance of the dissociator has
been studied by using a compression tube which wascalibrated by the D2 gas flow and was installed in the
middle of the ECR chamber. It should be noted thatthe previously used compression tube was uncalibrated
and was installed upstream of the ionizer. 1) The flux ofthe atomic beam into the 25-mm aperture has been obtained to be 2.3 x 1016 atoms/so This sufficiently highintensity implies that the dissociation degree is fairly
large and not causing the reduction of the polarization.
The current problem of the ion source operation is
the short lifetime of the insulators, particularly at thebeam-extraction section and at the Wien filter. Since
the N 2 buffer gas is fed in to maintain the stable
ECR plasma, an intense beam of nitrogen ions withvarious charge states and with a huge emittance isextracted. It hits the electrodes and yields a large
amount of metallic vapor, rapidly deteriorating the insulators. Recently all components of the extraction
electrode which were made of stainless steel have been
replaced by aluminum ones. The amount of metallic
vapor is significantly reduced and the ionizer can be
operated without maintenance for more than a coupleof months. Modification of the electrode of the Wien
filter is currently underway.
Also we have modified the transport beam-line to the
AVF (injector) cyclotron expecting the improved beamtransmission. Although it is not sufficiently tuned, thebeam with the intensity of 3.5 /-LA has been obtainedat the exit of the AVF cyclotron.
The spin-direction control is stably operated owing to the monitoring system of the single-turn
extraction. 2 ,3) Figure 2 shows an example of tuning the
Wien filter angle. The polarization is measured at 270
MeV and the polarimeter installed at the beam distribution corridor (D-room) is operated very efficiently
and reliably. A new polarimeter which also uses thed + p scattering as polarimetry4) has been installedat the exit of the beam 'swinger of the spectrograph
SMART. It moves with the beam swinger and thus
directly measures the polarization at the target. The
CH 2 target can be quickly inserted and removed by using a pneumatic actuator, which allows the periodical
monitor of the beam polarization during the experi-

0.6
Vector Polarization
0.4~

at 270MeV
0.2

0.0
-0.2

- 0.4

0.513 sin(p+256.25)

200
250
300
350
Wien Filter Angle: p (deg)Fig. 2. Dependence of px on the Wien filter angle, when
the beam is purely vector-polarized and the spin direction is rotated by 90°. The data is neatly fitted by asine function and its amplitude shows that the polarization degree, 77%, is not reduced. The statistical errors
are well within the size of the data points.

ment.
References
1) H. Okamura et al.: AlP Conf. Proc., 293, 84 (1994);
RIKEN Accel. Prog. Rep., 27, 130 (1993).
2) N. Inabe et al.: RIKEN Accel. Prog. Rep., 27, 133(1993).
3) T. Kawama et al.: ibid., p. 135.
4) N. Sakamoto et al.: ibid., p. 39.

149

RIKEN Accel. Prog. Rep. 28 (1995)

Modeling of ECRIS Beam-Intensity Upgrading-Technologies
M. Niimura, T. Kageyama, T. Nakagawa, A. Goto, and Y. Yano
Progress was made in fundamental understanding of physics for upgrading the beam-intensity(total-current and current-density) of high-chargestate (HCS) ions available from an ECR ion source(ECRIS) and its extraction/transport optics. Dueto the restriction of space, only the total-current
upgrading-technologies such as (i) electron (e-) beam
injection, (ii) wall-coating, and (iii) gas-mixing will be
discussed here. Currently, the upgrading factor (TJ) defined by the ratio of beam intensities 'with' to 'without' upgrading-technologies is approximately TJ(z) ~ 10
after (i) and (ii) are combined for argon ions, for instance, at the charge state, z ~ 14. The physical modelstudied here seems to provide knowledge on how to increase TJ beyond the present status.
Which property does actually upgrade the total
beam-current? In order to answer such a fundamental question and to investigate the individual roles ofelectron density (ne), temperature (Te) and ion confinement time (T) separately, we have developed ananalytic code that can compute the charge state distribution (CSD) under different parameters. The outline
is following.
The rate of increase of the z-times ionized ion density, n z (where z = 1,2,3 ,.. . ,Zn) , is given by

E1

(~1)

1)

{CXJe- x(:::::: ll/A ~dx = .\exp - ~(0~.\:::;0.5)(3)2= -0.097 + 0.343.\ - 0.015.\(O.5~'\~11.43)=(4)

1.863 (,\211.43)(5)

Figure 1 shows the numerically integrated E1 (1/ .\) ,whose polynomial form and saturation value are givenby (4) and (5) , respectively. These approximations
were found quite satisfactory compared with more rigorous calculation done by Lots (his Fig. 4).1) The L1
and G 1 are now calculable.

1.6:~ 0 .8
Q;

o

4
6
8
10
z 1
Lamda, A. = T/ E_ .

12

dnz

dt = [neSz-1 ,z] nz-1 - [neSz,z+l+ nopz ,z-l Vi + l/T] n z + [nopz+1,zVi] nz+l. (1)The first and third bracket terms in Eq. (1) are production rates of n z ions due to the electron impact
against nz-1 type particles (G 1) and due to the charge
exchange of nz+1 ions with no (G2), respectively, while
the second term consists of loss rates of n z ions dueto the ionization (Ll) , charge exchange (L2), and ion
diffusion (L3) processes.
Sz-l,z :::::: ((Tz-1 ,zV e) in Eq. (1) is the ionization rate
coefficient or an averaged (TV per particle averaged over
Maxwellian distribution of the electron thermal velocity. Since we are interested in the HCS ions (z ~ 4),
the stepwise electron impact ionization cross-section
can be expressed by a simple form: 1) (Tz- 1,z = azqz(lnUz/U z) (E~l )-2 [cm 2]. Here, Uz :::::: c/E~l ~ 1,
c :::::: (1/2)mev; , Bethe coefficients azqz = 4.5 x 10- 14
because z ~ 4, and E~ 1 is the ionization (or binding) energy of z-1 type particles. The Maxwellian
averaging results 1)(1).
_ Te(eV)_ 3.02 x 10- 6(2)
T~/2.\ E1 ~ , If .\ = E~l
Sz-l,z The exponential integral, E1 (1/ '\), appeared above has
no analytic form except for the limit, .\ ---+ O. We thus
have numerically derived relevant expressions:150

Fig. 1. Numerically evaluated exponential integral,
I:::::: E1(1/,X), used for the calculation of Sz-l,z('x).

As for the charge exchange cross-section, we haveused the Muller-Salzborn expression 2): Pz,z-I = 1.43
X 10- I2 z1.17 /(E~)2 . 76 [cm 2] where E~ is the first ionization potential of neutrals (no). The loss L2 takes
place when z-ions collide with no, where the relative
velocity of encounter is essentially the ion thermal velocity, Vi.
On the other hand, L3 :::::: nz/T is inversely proportional to the ion lifetime, T :::::: L/Vi (L: effective wall
distance). Within this report , we assume T to be independent of z. The case T(HCS) ~ T(LCS) will be studied
elsewhere.
At the steady-state (dnz/dt = 0) the rate equation (1) is in the form: [Az,z- I]nz- 1 - [Az,z]n z +[Az,z+dnz+I = O. The matrix equation for the first 5species can be expressed as00-AlOnoAll A 12 , 0
nl
0
0
n2
A21 A22 A 23 00
0 A32 A33 A34 0 x n3 =00
0 A43 A44 A45
n4
1
2
3
4
5
n5
ne

The last row is the charge neutrality condition.

(6)

Firstly, the complete 18 x 18 matrix elements
Aij have been computed for argon (J..L = 40) ion
system under the RIKEN f = 10 GHz ECRIS
conditions: p = 1.8 X 10- 6 [Torr], noi == 9.66
x 1018p /T(K) = 5.79 x 10 10 [cm- 3 ], ne == 1.24 x
10- 8f2 = 1.24 X 10 12 [cm- 3 ], no = nOi/2 = 2.90 x
1010 [cm 3 ], a == ne/(ne + no) = 97.7%, T e = 500 eV,
Ti = 0.5 eV, Vi == 9.79 X 10 5T i /(J..L)1/2 = 1.09 X 105[cm/s], R = 10 cm, and T = R/Vi = 91.7 J..LS. Then,the 18 simultaneous equations were solved by a Gaussian elimination method.
Figure 2 presents computer results of CSD , wherea monotonical decay of n z with respect to z ischaracteristic for both curves with diffusion loss,
l/T = 1.09 X 104 s- 1 =1= O. However, magnitude of n z
increases when ne is raised. This means that the total
beam-current, Iz = ZenzvesS (v es : escape velocity) will
be upgraded if all the electrons externally "injected"
via technologies (i)-(iii) are ECR heated and thermalized to the same T e = 500 eV as the backgroundplasma. What happens if they were not heated? Then,the density of hot electrons won't increase. However,if the e-beam injection could trap ions indefinitely sothat no diffusion loss takes place (l/T = 0), a significant upgrading much greater than the previous neeffect can be expected; e.g., TJ = 00 at z = 12. This isevident in Fig. 2 by comparing the l/T = 0 with l/T
12 cm- 3 .
=1= 0 curve with ne = 1.24 x 10

Figs. 2 and 3 show that those l/T = 0 curves characteristically increase with z, and the peak shifts towards
higher-z to attain a higher-nz as ne is raised, followed
by a decay due to the increase of L2 at large-z. On theother hand, if charge exchanges were negligible beside
L3 = 0, then nz/nz-1 ~ G1/L1 = Sz-l,z/Sz,z+l whichis always an increasing function with z. Such a condition (L2 = L3 = 0) may be satisfied when Vi or (Ti)1/2
is lowered via the technology (iii), since L2, L3 rv Vi.
For this case, the n z will start decaying abruptly, regardless of n e, after a certain z at which A == Te/E~l:S 1, as observed by Antaya. 3 )Figure 4 shows one of our experimental results,
where a tuning was made only for Arll+ ions, while applying technologies (i) and (iii). Although quite similar
with l/T = 0 curves in Fig. 3, whether this is representing the case of L3 = 0 or L2 = L3 = is yet to be
confirmed; the tuning for all z's may result in a profile
similar to the l/T =1= 0 curves seen in Fig. 2. Since L3
is actually scaled by Vi/c/>, the L3 = 0 condition may
be satisfied if a potential-dip, (8c/>/8r ~ 0), is created
via the technology (i).

°

50

l
~

c

~

B

c
0

30
20

'"
~

III
4

6

8

10

12

14

Charge State, q IN/A]

Fig. 4. Experimental CSD in linear-scale for argon ions,after correcting the overlapping effects at z = 10 and 5.

6

8

10

12

14

16

18

Ion Charge State, z [NIDJ

Fig. 2. Theoretical CSD in log-scale with and without theion diffusion loss (l/T) and the effect of various ne.

Figure 3 shows linear plots of two 1/T = 0 curves
together with one l/T =1= 0 curve. It is evident from

c:

•

~

2

1.010

o

.~

8

50

"
E
Z

.0

4

6

8

10

12

14

Charge State, z [NIDJ

Fig. 3. Theoretical CSD in linear-scale, for argon ions at
Te = 500 eV, similar to t.he case of Fig. 2.

Among the upgrading technologies, either L3 = 0 or
L2 = L3 = 0 type is more beneficial than the largene type for the sake of AVF cyclotrons which accept
only the particle at z ~ M/4. We presently inject ionswith z close to the minimum z = M/4 (=10 for argon) into cyclotrons by automatically assuming thatthe beam-current always decreases with z. However,present study has revealed that the CSD can increase
with z and its peak can shift towards higher-z under loss-less cases; one can then accelerate ions with z
higher than now without sacrificing the beam-current.
Conclusion: The effect of large-T can be much greaterthan that of increasing ne by an order of magnitude
which requires a raise of RF frequency by 3-times (to30 G Hz if lOG Hz now). The technology (i) lowers thehight of the plasma potential with a dip-c/> on the axis,
thereby reducing the ion diffusion loss while raising ne.
References
1) W. Lotz: Z. Physik, 216, 241 (1968) .
2) A. Muller and E. Salzborn: Phys. Lett., 62, 351 (1997).
3) T. A. Antaya: J. de Phys. G1, 50, Cl-707 (1989).
151

RIKEN Accel. Prog. Rep. 28 (1995)

Development of High-T e ECRIS Plasma Diagnostics
M. Niimura, A. Goto, and Y. Yano
The averaged excitation rate coefficients of helium(HeI) lines have been calculated for the first time beyond the range of previous calculation 1) limited by
Te ~ 100 eV. The result indicates that the electron
temperature (Te) of ECR ion sources (ECRIS) canbe measured spectroscopically up to T e = 1000 eV, byutilizing the helium atoms left from turbomolecularpumping.
ECRIS plasmas are characterized by a high-T eplasma, which is a pre-requisite for production ofhigh charge-state (z) ions. In a thermal plasma,T e 2: 1.44E~ 1 should be achieved if more than 50%of the electrons should participate in the productionof z-ions from (z -1)-ions with the ionization potential, E~I(=539 eV for Ar, z = 11). A non-perturbing
T e monitor is thus needed in order to readjust machineparameters for the efficient, stable ion beam production throughout the course.
On the other hand, ECRIS plasmas are practicallya dual-gas plasma; mixing of a supporting gas withthe target gas is a common practice for the purpose toenhance the extracted ion beam-current. Our idea is
to utilize one of the light gas atoms like HI and HeI as a
Te monitor. This would not raise the ECRIS working
pressure (typically 10- 6 Torr) since one can use HI or
HeI left over in the vacuum system. High-T e low-ne(typically 1011 "-'12 cm- 3) characteristics of the ECRIS
plasma tend to satisfy the condition of tenuous plasma
model 2) used below.
As is well known, the hVmn photon emission due tothe m---+n (m > n) line transition has the intensity
expressed by Imn = (1.6 X 10- 19 /47r) (hvmn)AmnNm[W /cm 3 sr]. Also known is that in a low-ne plasma
the radiative decay rate balances with the collisional
excitation rate, i.e., AmnNm = Ne(anm v)N n , wherea nm is the n---+m collisional excitation cross section. This is called corona model, which is valid
if T e ;::: 10 e Y in the plasma with ne = 1.24 x 1012
cm- 3 (critical density of 10 GHz ECRIS). Particularly, if T e » ~Elm' a tenuous plasma condition holds
meaning that the population of lower transition levelis close to that of ground level (N n N 1)' Then,
Imn = (1.6 X 10 19 /47r) (hvmn ) N e (anm v)N 1. Lees 3) has
experimentally confirmed the proportionality of Imn
against N e, N 1, and a nm during his a nm measurement.
Therefore, the relative line intensity (RLI) ratio ofm---+n transition to m'---+n' (m' > n') transition is givenbyThe factor (~Enm/ ~EnJmJ) is missing from the Sovie's
expression 1) of Xc. The term (anm v) in Eq. (1) denotes
the averaged excitation rate coefficient per particle defined byHere, v( e) is the impacting electron velocity expressedby the kinetic energy, e = (1/2)mv 2, and g(e) is theMaxwellian distribution in the 3-D energy space:

Using de = mvdv, Eq. (3) can be reduced to a morefamiliar form: (m/27rT e)3/2 exp( -mv 2/2Te)47rv2 ==g(v)dv , where 47rv 2 is a volume element in the spherical coordinates. Substituting (3) and v(e) == (2e/m)I/2
in to Eq. (2) we obtain

Here, ~Enm is the threshold energy to observe a finite
a nm , and (8/7rm)I/2 = 6.68 x 10 7 when T e and e arein eY.
Our objective is to evaluate Eq. (4) for various
atomic lines in the range of T e relevant to ECRIS.
McWhirter 4 ) has evaluated x o , but only for Te ~ 100
eY (like Sovie's case) and for 471.3 nm (2 3P-4 3S) and
492.1 nm (21 P_4 1D). Sovie 1) has later pointed out thatthe a nm of D (diffuse )-series has a peculiar pressure dependence so that use of McWhirter's Xo may lead erroneous T e, while the a nm of S(sharp)-series has nosuch a peculiarity over the range, 0- 130 mTorr. Thispressure range covers well the ECRIS working range,
0- 0.01 mTorr.
Figure 1 shows two profiles of the experimentally

1 .6

,

HoI (H,' ')f"VHere, ~Enm[eYl == hVmn == 1239.8/A mn (where Amn isthe wavelength of m---+n emission in units of nm).
152

P~SSibIC ~'ionl

tl 0 .8

II

0.4

Extraporaled~jo L-~~~~~~~~~----~

10

(1)

j

100

1000

Impacting Electron Energy. £ leV]Fig. 1. A veraged excitation cross sections of HeI singlet-singlet eS) and triplet-triplet eS) lines. Symbols
are data points read from Lees ' experimental curves. 3 )observed a mn (E) of HeI lines in the S-series: 3) the 1S
and 3S denote 443.7 nm (5 1S-+21 P) and 412.1 nm(5 3S-+23p) transitions, respectively. These profiles
are self-similar when the series of the upper state issame. The IS and 3S profiles peak at E = 36 eV
and 30 eV, respectively, and the ratio of peak values
is aeS)/a(1S) = (4.5 x 10- 2°)/(2.8 x 10- 2°) = 1.607.
Lees' experimental curves of a mn (E) terminate after
a certain E, but they obviously ought to continue tillamn(E) = o. In Fig. 1 a smooth extrapolation was
thus performed for IS and 3S curves in the range ofE ~ 500 eV and E ~ 120 eV, respectively. We suspectthat Sovie 1) has prematurely truncated both IS and
3S curves at around E = 300 eV, as marked in Fig. 1,
since he did not multiply the factor of (~Enm/ ~Enm/)in (1), but ended up with X o agreeable with ours.
The curve of amn(E) may be approximated by either Bethe approximation of a = a In(c) / E type or
Wooley-Allen approximation of a = (a/E)[b - (l/E)]
type,5) where a and b are constants.
However,within the present work frame we have evaluated Eq.
(4) numerically. Figure 2 presents the numericallyevaluated excitation rate coefficients for the IS and 3Stransitions as a function of T e.

8
7

0' 6
~ 5
o

x

o 4
~

q: 3
:J

a: 2

a

1
Electron Temperature, Te reV]

Fig. 3. The computed RLI-ratio, Xo(Te) = 14437/14142
which can determine Te in the range, 20 ::; Te ::; 1000
eV.

3

2.5
0

2

z
x

0

.£

1.5

iii

q:

:J

a:

x (1 . 8 7 x 1 0- 1 2)

0.5

~6

0

(')

E
~5

~4

c

20

40

60

80

100

Fig. 4. Comparison of our result with Sovie's in the domain 0 ::; Te ::; 100 eV.

Q)

·6
:a5
o

a

Electron Temperature , Te reV)

"

3

()

*

1

J

a: 2
c:

o

~
·6
~

0 1~~~~~~~~~~~~~~~
10
100
1000
Electron T emperatu re, T e [e V]

Fig. 2. Excitation rate coefficients of Eq. (4) as a functionof T e for both 1 Sand 3S transitions.

Taking the ratio of the two curves presented
in Fig. 2, and multiplying it by a factor of(~Enm/ ~En/m/) = 2.79 eV /3.00 eV = 0.93 , we haveobtained the curve of Xo ::::::::; 14437/14142 as shown in Fig.
3 over a wide range of 5 ::; T e ::; 2000 eV. This graphshould be useful in the plasma diagnostics for determining Te from measured x o , up to 1000 eV; resolution
deteriorates above 1000 eV.
For the sake of comparison of our result with Sovie's, the portion of Te ::; 100 eV has been re-plottedin linear scale in Fig. 4. A fairly good agreement isevident between the two curves. However, we can saythat the same result as ours may be reached even af-

ter truncating the a nm (E) at around E = 300 eV if themultiplication factor (~Enm/ ~En/m/) was neglected in
Eq. (1).
In conclusion, we could extend the temperature
range so that T e of up to 1000 eV can be measured by anon-perturbing method. The hot-component of Te (orT eh) in many two-temperature ECRIS is within thisrange. The energy analyzer diagnostics 6 ) determined
T eh = 240 eV for a typical ECRIS plasma, Caprice.
The charge state distributions of the LBL and RIKEN
10 GHz ECRIS agree well with theoretical predictions,if Teh rv 500 eV.
References
1) R. J. Sovie: Phys. Fluids, 7, 613 (1964) .
2) R. Wilson: J. Q. Spec. Rad. TransJ., 2, 447 (1962).
3) J. H. Lees: Proc. Roy. Soc. (London), A137, 173(1943) .
4) R. W . P. McWhirter: Plasma Diagnostic Techniques,
Academic Press, New York, p. 201 (1965) .
5) H. V. Regemorter: Astrophys. J. , 136, 906 (1962).
6) K. S. Golovanivsky and G. Melin: Rev. Sci. Instrum.,63, 2886 (1992).

153

RIKEN Accel. Prog. Rep. 28 (1995)

Construction of a High Density Polarized 3He Gas Target
T. Uesaka, M. Wakasugi, T. Wakui, and A. MinohA high density polarized 3He gas target system has
been constructed. The 3He nucleus is polarized bya spin-exchange reaction with a polarized Rb atom.
The polarized Rb atom is produced by optical pumping
using a circularly polarized laser beam. Our goal is torealize more than 60% polarization of 3He at a gas
density of about 10 atoms at room temperature.
To achieve high polarization, both long relaxation
time and high laser power are necessary. The 3He polarization at equilibrium is expressed as follows:'YSE

P3He =

+

'YSE
'YSE
'YSE

(1)

rPRb

'Yopt

(2)

+ r 'Yopt + rSD'

where 'YSE is the spin exchange rate between Rb atomand 3He nucleus , r the total spin relaxation rate, P Rb
the polarization of Rb, 'Yopt the optical pumping rate,
and r S D the spin destruction rate of Rb atom. From
Eq. (2), the conditions to obtain high polarization arefound to be

r,

(3)

» r SD·(4)'YSE »'Yopt

Figure 1 shows a schematic view of the target system. As a pumping laser, we chose a 4W laser diode(Spectra Diode Labs SDL-2382-P1), whose wavelengthis 798 nm at room temperature and spectral width
1.3 nm. The divergent beam from the laser diode isformed by lenses to have a proper beam envelope atthe target cell. Circular polarization is produced by a)../4 plate.

The target cell, which is made of aluminosilicate
glass (Corning1724), is heated up in a 180°C ovento control the density of Rb atoms in the cell.
The polarization of 3He is measured with the adiabatic fast passage NMR (AFP-NMR) technique. The
AFP-NMR system consists of 3 sets of coils: main coils,
drive coils and a pickup coil. They are set perpendicular to one another. Main coils produce a static field(B rv 30 Gauss) and the drive coils provide an RF field(w rv 100 kHz). When the static field which is swept
slowly coincides a resonance (B = wl'Y, where 'Y is agyromagnetic ratio), spin of the 3He nucleus is flipped
and the signal which is proportional to the polarizationof 3He nucleus occurs in the pickup coil. The main coils
are designed so that inhomogeneity of the static field
is sufficiently small (D..BIB S 10- 3) in the volume of
the target cell, to suppress the relaxation caused by
the field inhomogeneity.
Two Major relaxations are caused by a cell wall andimpurities in the bulk gas. To reduce the wall relaxation, cleaning procedure of the cell is very important:first , we remove ferromagnetic contaminants on thesurface of glass cell with nitric acid. Next, we get ridof organic impurities with acetone. Finally, the cell iscleaned in ethanol with a ultrasonic cleaner.

drive coilFig. 2. Cell making system.
laser beam

main coilFig. 1. Schematic view of target system.
154

The vacuum system for gas filling was designed toreduce the impurities in the bulk gas (Fig. 2). A
quadrupole mass analyzer is very useful to monitor
components of the residual gas. A ballast and a liquid
helium trap are devices to purify 3He gas. 1) The ultimate pressure of this system is 9.3 x 10- 9 Torr. The
cell is baked at 250°C in the vacuum for several days.
The glass ampule which contains Rb is broken in thevacuum and the Rb is chased to the cell by a heating

gun. After that , a small amount of nitrogen gas, used
as a quench gas, is frozen into the cell. A 3He gas purified through the ballast and the liquid helium trap istransferred to the cell at last.
The construction of the whole system has been completed, and a preparation for the first cell production

is now in progress.

References
1) N. R . Newbery et al.: Phys. Rev. , A48, 4411 (1993) .

155

RIKEN Accel. Prog. Rep. 28 (1995)

Monitoring System of Single Turn Extraction in Cyclotrons
M. Kase, N. Inabe, I. Yokoyama, T. Kawama,* A. Goto, and Y. Yano .
In order to get a high-quality beam from the RIKEN
Ring Cyclotron (RRC) , it is essential to realize thesingle turn extraction in the two cyclotrons (AVF cyclotron and RRC). As for RRC, the single turn extraction can be easily judged!) in both cases of the injections from AVF cyclotron and RILAC. In this year,
the system was extended, involving the monitoring of
the single turn extraction in the AVF cyclotron. And
the beam phase measurement becomes possible at thesame time.
The principle of monitoring the single turn extraction is illustrated in Fig. 1. A beam bunch, which is accelerated in the extraction orbit of the AVF cyclotron,
is divided into two parts by a septum electrode of a deflector in the case of the double turn extraction. These
two fragments from one bunch appear in the extraction beam line, being separated by a time difference of
2 x To (To is the period of rf in the AVF cyclotron)
because the harmonic number of the AVF cyclotronis 2. Normally the fragment is paired with a complementary fragment from the adjacent turn, forming
one beam bunch apparently, although their energies
are slightly different. However, at the transient time

when a beam starts or stops, these fragments appear
separately, as shown in Fig. 1.
The beams are stopped partially (500 ns duration)and periodically (about 10 kHz) by a beam chopper in
the injection beam line of the AVF cyclotron. Since thebeam loss due to this effect is less than 1%, this beam
modulation can be continued all the time, even during
an experiment. The beam chopper is capable of switching on and off the beam completely within the durationof 2 x To. 2) A time structure of chopped beam from
cyclotrons has been continuously monitored with two
sets of probes with a micro-channel plate (MCP),l) one
is at the location of beam line just after the AVF extraction, and the other just after the RRC extraction.
The block diagram of electronics is shown in Fig. 2.
Two sets of preset counters are newly employed as adelay generator up to 100 J-LS.
A typical time spectrum obtained at the extraction
beam line of the AVF cyclotron is shown in Fig. 3.
The small peaks appearing in the duration of beamswitched-off are mainly due to the multi-turn extraction. When the single turn extraction is completely
realized, these small peaks disappear except those due

Extracted beam

Injected beam

NbunchN bunch> h-IIn case of the double turn extraction

In case of the single turn extraction- - ----- ~-- -- -----~--- ----- -- & -- - ~r--Fig. 1. A conceptional illustration of the principle of monitoring the extraction in the AVF cyclotron. The
solid circles show the bunch of full beam, while smaller ones are partial bunch due to the transient effectof the chopping. The number of bunches, which are cut by the beam chopper, should be greater than theharmonic number (denoted by h) in this scheme.
Sumitomo Heavy Industry Ltd.

156

300

7 MeV

p

MCP AVF
Trigerto
Beam Chopper

To =6l ns
::r::

U

GPm

t

H

200

~
~
o

u

Peaks due tothe multi-tum extraction

100

~

o

..j

.J

o

50

100

I

150

.,

200

. .l ...

.l

250

300

CH NO.

Fig. 2. A block diagram of electronics. Arrows with dotted line show the remote connection to a host computer(Mitsubishi M60/500). The numbers of nl and n2 are
the preset values to the counter used as a delay generator.

to the transient imperfection of the beam chopping. In
this way, one can know quantitatively how the single
turn extraction is realized inside the AVF cyclotron.
The turn numbers inside the cyclotrons are obtained
from the values of delay time, ~tk = nk To (k = 1 for
the AVF and k = 2 for the RRC) in Fig. 2, if thedelay time of signals in cables and the flight time ofbeam outside the cyclotrons are taken into consideration. The position instability of peaks in the spectrum

j

350

j

J
400

-

J

J

450

500

TIME

Fig. 3. An example of time spectrum of 7 MeV proton beam measured with MCP probe at the exit of the
AVF cyclotron. The spectrum involving a moment ofbeam-off structure was found after searching an appropriate value for nl in Fig. 2, and was stored in an MeA
for 1000s. The peaks, which appear every 61 ns, arecorresponding to one beam bunch.

due to the drift of the delay-time was improved after the new digital delay generator was employed. Itmeans that the measurements in the same system work
also as a phase monitor which tells us how much magnetic fields drift inside the cyclotrons.!)
References
1) M. Kase, T. Kawama, T . Nakagawa, N. Inabe, I.
Yokoyama, A. Goto, and Y. Yano: Proc. 9th Symp.
on Accelerator Science and Technology, Tsukuba, Aug.,
p. 474 (1993).
2) N. Inabe et al.: RIKEN Accel. Prog. R ep., 27, 133(1993).

157

RIKEN Accel. Prog. Rep. 28 (1995)

Study of the Beam Transport between the AVF
and Ring Cyclotrons
N. Inabe, T. Honma, M. Kase, A. Goto, and Y. Yano
We studied the optics of the beam-transport line between the AVF and the Ring Cyclotrons (RRC) to improve efficiency of beam transmission in the line. Figure 1 shows the transport line. At first we measured
an emittance of the beam extracted from the AVF Cyclotron (AVF). And then we searched one of the bestsolutions for the optics.

1~---transfer matrix by two methods. One is performed bychanging the field strength of the quadrupole magnet(Q-magnet) located just before a beam profile monitor.
Another is done by changing a measuring point for the
fixed field strength of all Q magnets in the line. By
the former, the emittance of 22Ne lO + 5.3 MeV lu beam
was measured at PFCOIA, PFS31 , and PFS65. By thelatter, that of 14N7+ 7.0 MeV lu was measured at thestraight section after the AVF using three profile monitors located at PFC01A, PFC01B, and PFC02. In themeasurement we took care so that the intensity did notdecrease with changing the strength of the Q-magnet.
The results of the measurements are shown in Table 1. For the horizontal direction of 22Ne 10 +, thePFS65

Table 1. Measured emittances.
Emittance (7r*mm*mrad)
Location Horizontal
Vertical

from
RILAC
PFS31

+ 5.3 MeV lu PFCOlA
PFS31
PFS65
14N7+ 7.0 MeV lu

/

22Ne

PFC018

1- 10 ,
' LJ"'U"""~~'~ - - _ ..
between the AVF and the RRC .
.L.

- - -0- -_____sport line

Measurement of the emittance was performed withthe beams of 22Ne 10 + 5.3 MeV lu and 14N7+ 7.0
MeV lu. The emittance of transverse beam c is represented by using matrix elements of a (J matrix as;(1)

The relation between (J - matrices after ((J 0) and before ((Jj) passing through the transport line is given bya transfer matrix of the transport line (R) ,(2)
Since (Jll equals the square of a beam size , (Jj canbe obtained from the measurement of beam sizes corresponding to several transfer matrices and also the emittance can be calculated from Eq. (1). We changed the
158

10

14
7

9
15

6.5

25

7.9

7.6

measured emittances at PFS31 and PFS65 are almostin good agreement with each other. The one fromPFCOIA is rather larger than those from PFS31 and
PFS65. The reason might be due to two peaks of the
profile clearly appearing at PFC01A since the beam
was not extracted with single turn at that time. To
check accuracy of the measured emittances at PFC01Aand PFS31, we compared each beam size of the transport line calculated from the obtained (Jj with the measured one. The beam sizes which were calculated using
the result of PFS31 almost reproduced the measured
ones but those from PFCOIA did not. We also compared the emittance measured at the location of PFS31
with that of 14N7+ beam. They were in good agreement with each other. From the analysis we conclude
that the beam emittance extracted from the AVF is
rv77r mm*mrad in the horizontal plane. In the vertical plane the emittances of 22Ne lO + beam measured at
PFCOIA , PFS31 and PFS65 are not in good agreement
to one another. The emittance measured at PFC01A
was close to that of 14N7+ beam. For the vertical direction we also performed the same analysis as for thehorizontal direction. The beam sizes calculated using
the result of 14N7+ beam almost reproduced the measured ones but those using the others did not reproduce
so well. From the analysis we adopt rv77r mm*mrad as
the emittance of the vertical direction.

With the measured emittance, we searched a solution for the optics of the transport line. Using the parameter searched, the transmission of the beam fromPFS31 to PFS65 was raised up particularly and total transmission for the beam line amounted to morethan 90%. Because the shape of the beam emittancedepends on the way of extraction of the beam fromthe AVF, we must tune the AVF so as to extract thebeam with almost the same shape of emittance. Thatis performed by checking the beam pattern of extracted
region and the beam profile at PFCOIA.
The obtained parameter is also applied to all kindsof beams and the transmission between the AVF and
the RRC is more than 90% for all the beams.

159

RIKEN Accel. Prog. Rep. 28 (1995)

Development of a New Type of Single-Bunch Selector
N. Inabe, M. Kase, 1. Yokoyama, A. Goto, and Y. Yano
A new type of single-bunch selector reported in thelast progress report has been developed so as to havea high repetition rate. 1) Since the repetition rate of
the old system (25 kHz) was limited by the talent of
the switching module, we constructed a new switchingmodule and raised the repetition rate up to 1 MHz.
Figure 1 shows a schematic drawing of the circuit of the

From

AVF
SG

Pulse

new switching module can make a pure single bunchedbeam as the old one can. The system was also newly
installed between the polarized ion source (PIS) andthe AVF cyclotron (AVF).
A performance study of the single-bunch selector
was carried out for the 7.45 KeV Ht beam fromthe PIS which was accelerated to 7 MeV/nucleon by
the AVF with an RF frequency of 16.3 MHz and to
135 MeV/nucleon by the Ring Cyclotron (RRC) withan RF frequency of 32.6 MHz. The setup is shownin Fig. 2. A duration time during which the voltage
between the electrodes was switched off was 150 ns.
Voltage of the electrodes was 470 V. The variable delay connected with the switching module was adjusted
so as to get the purest single bunched beam for the
RRC. Time structures of the beam after the AVF and
RRC were measured by using a time of flight (TOF)
between a reduced RF signal and a timing signal of
micro channel plates (MCP's) with a target. 2 )Fig. 1. Schematic drawing for the circuit of the newswitching module.

switching module. As shown in Fig. 1, the switchingmodule has two trans-coupled switches with repetition
rate of 1 MHz (HV 1000 P, N), which are sold from DEI
inc in USA. One is for the charge-up of the electrodeand the other for the discharge. To avoid an electricaloscillation between two switches and the electrode, we
inserted two 20 ohm resisters and two 50 ohm ones.
Two pulses for the switches are made by a pulse generator located at upstream of the switching module.
One is a leading pulse which is sent to the switch fordischarge and the other is a delayed pulse which is sent
to the one for charge. The difference of time when eachpulse arrived at each switch corresponds to the duration of the chopped beam. Characteristics of the pulse
made by the new switching module are summarized inTable 1. Although the voltage of the pulse is lower
than that of the old one, it is high enough to makea single selection because the voltage to be needed is
500 V. Also the duration time is as short as that of
the old one. From the properties it is shown that theTable 1. Characteristics of the pulse made by the new
system.
Voltage
Repetition rate
Rise time
Duration time160

0- 500 V (DC)< 1 MHz
15 ns
100- 250 ns

Fig. 2. Setup for a performance test of the single-bunch
selector.

Figure 3 shows a typical example of the TOF spectrum of the AVF. The main peak in Fig. 3 is due to asingle bunched beam to be extracted. The peak next
to the main one is due to the next bunch of the mainone. The existence of the other two peaks means thatthe same bunch inside the AVF cyclotron is extractedwith two-turns. Production mechanism of those peaks
is explained in Ref. 1. The result of the many peaksin the spectrum might be caused by the adjustmentof the variable delay that is suitable to the RRC. In
fact, using the system we obtained the single bunchedbeam as shown in Ref. 1 by adjustment of the variabledelay for the AVF and by singlet urn extraction fromthe AVF.

TOF SPECTRUM OF BEAM FROM AVF
200 ~--------------------------------~

.l1l

§ 100
o

()

turn of the RRC (right side) and that of the AVF (leftside) . The purity of the single bunched beam is ",80%.
Production mechanism of those peaks is explainedin Fig. 5. As shown in Fig. 5, in principle, the otherturn of the AVF gives a bad effect to the single bunchedbeam extracted from the RRC but the peak of the turnis not so strong. This might be due to bad transmissionof the RRC for the turn.

DeflectoLl::. TRRC
50

100

150

200 250 300
Channel

350

400

450

500

Fig. 3. An example of time spectra of the beam extracted
from the AVF cyclotron. T_avf means the RF period of
the AVF cyclotron.

1

TRRC\ Another turn inboth AVF and RRC" Anotherturn in AVF•

Originated from main bunch

D

Next

Bunch

Originated from next bunch

TRRC RF period of RRC ( = O.5°Tavf )/NTime Structure of RRC

r-------------------------------~

Figure 4 shows a typical example of the TOF spectrum of the RRC . The main peak in Fig. 4 is made by
the single bunched beam to be extracted. The peaks
next to the main one are due to the next bunches of themain one. The two small peaks correspond to another
Another turn inboth AVF and RRC
TOF SPECTRUM OF BEAM FROM RRC

Fig. 5. Time structure of the beam from the RRC for twobunches with two-turns extraction in both the AVF and
the RRC.

10000

8000
2T_rrc2T- rrc\.l1l 6000c::::l

4T_rrc

0
()

---

~ f--

4000

The value of the purity is large enough for usualexperiments but not for those which need low background. The next step of the system is to get a purer
single bunched beam. For the purpose it is planned
for the frequency of the buncher located at upstreamof the AVF to be 1.5 times as large as that of AVF.

~

5T rrc--- r--J.-=.

2000

1

o

50

100

150

200

250 300
Channel

350

400

450

500

Fig. 4. An example of time spectra of the beam extracted
from the RRC. TJrc means the RF period of the RRC.

References
1) N. Inabe et al.: RIKEN Aceel. Prog. Rep., 27, 133(1993).
2) T. Kawama et al.: ibid., p. 135.

161

RIKEN Accel. Prog. Rep. 28 (1995)

Replacement of Computer for the RRC Control
M. Kase, A. Goto, and Y. Yano
The Ring Cyclotron (RRC) , the AVF cyclotron, andthe heavy ion linac (RILAC) have been controlled bymeans of a network of three mini-computers (Mitsubishi M60/500).1) About 10 years have passed after
the first installation of these computers, and now it
becomes gradually difficult to continue a maintenancecontract with a computer maker due to a shortage ofspare parts of these computers. Thus we decided tochange the computer#1 (the oldest one of the three)into a new one (Mitsubishi M60/ AR), which is an upgraded machine of M60/500, without changing a basicarchitecture of the control system.
The computer#l, which was designed originally to
be used for a program development, has been used
for continuous monitoring, such as beam qualities, rf
voltages and phases, temperatures at many points of
the whole accelerator site, and also used for storage ofthese data in its memories. The computer#2 has beenused for control of RILAC via a GPIB interface. The
computer#3 has been a main control computer connected with the whole devices of the RRC and the AVF
cyclotron via a DIM-CIM system through a CAMAC. 1)
The replacement was done in the following way; A
new computer (M60/ AR) was installed in a place ofthe computer#1 which was removed this time, and isused as the main control computer instead of the computer#3. The CAMAC system including a serial highway driver (SHD) board is unchanged. Man-machineinterfaces at the control console, such as touch panels and graphic displays, are the same as before. All
the control programs, which have been developed by
RIKEN staffs, are still available in the new system.
The computer#3 is used in turn instead of the computer#l , being also standby as a backup computer tothe main control one. It can be connected back shortly,
since old connection cables are kept remain under afloor of the control room. Some component parts ofthe computer#1 are stocked nearby as spare ones andwill be used in case when some troubles occur with theold two computers in the future.
A comparison of performance of M60/500 and thatof M60/ AR is given in Table 1. The new system has
Table 1. A comparison of the performance.

Processor number
Command speed
Main memory size
DMA channel
Disk memory size

162

M60/500
1
3.7 MIPS
5 MB
0700 MB

M60/AR2
9.7 MIPS
32 MB
2
1.4 GBtwo direct memory access (DMA) channels in order
to lighten the main cpu load under the condition ofmulti-task processing. Since the new system supports
the standard network, it is easily connected with othercomputers. The final configuration of the new control
system is shown in Fig. 1.

·········1__ J~: CONTROL

CMT

Fig. 1. The new control system of the RIKEN Ring Cyclotron and the AVF cyclotron. The shadowed parts are
installed newly at this replacement . Figures in parentheses are the number of devices. FXD; fixed disc memory, FDD; floppy disc driver, CGD; color graphic display, TP; touch panel, RE; rotary encoder, PP; page
printer, HC; hard copy, SHD j serial high way driver,
CMT; cartridge magnetic tape, TSS; terminal, DW;
data way controller.

The replacement of hardware was done during a
shutdown period in this summer. The software installation was completed before the end of September.
The final adjustment to improve the performance between the CAMAC system and the computer is now inprogress.
References
1) T. Wada, J. Fujita, I. Yokoyama, T. Kambara, and H .
Kamitsubo: Sci. Papers I. P. C. R. , 79, 28 (1985).

RIKEN Accel. Prog. Rep. 28 (1995)

Construction of a New Injector System for RILAC
A. Goto, o. Kamigaito, Y. Miyazawa, M. Hemmi, N. Inabe, M. Kase, T. Nakagawa,T. Chiba, S. Kohara, and Y. Yano
A new injector system of RILAC is being constructed in order to increase beam intensities of heavy
ions by one or two orders of magnitude. The system
consists of a high-field, high-frquency ECR ion source,
a variable frequency RFQ linac, and a beam transportsystem between them. Figure 1 shows a schematic
drawing of the system. Details of each part are described in Refs. 1, 2, and 3, respectively.

~

Power
amplifier

~

:2
0
c::
CI)

(40 kW)(5C/)

Main characteristic features of the designed ECR
ion source are as follows: (1) it is operational at 18
GHz, (2) it is of a single-stage type, (3) both of theaxial mirror field and the radial hexapole field are highenough for not only the fundamental-frequency operation but also the twice-frequency operation, and (4)the plasma cathode method 4) is applied to it. The reason for adopting the single-stage type is that very high

g
~.~ ~

asc::

~
~

a ~ E~
>.

~

~.-;

0

as:§Q)
as E eu.wa..

~

as
0

a>

to RILAC•

FC-RFQlinac- - Einzellens

o

1m

18GHz

- - - 18 GHz ECRIS

Klystron(1.5 kW)--+-----..~-----"r_'IO"'"

Fig. 1. Schematic drawing of a new injector system of RILAC.

charge states are not necessary for RILAC , and that
this type has high performance for low charge statesin contrast to a two-stage type. Beams are extractedwith a maximum voltage of about 10 kV.
The RFQ linac is required to have the same function as that of the existing 450 kV Cockcroft-Walton
terminal. It is designed to accelerate ions with a range
of m/q = 7- 28 up to 450 keY /q in the CW mode.
The operational frequency should be varied between 17
MHz and 35 MHz, which is one of the most important
problems to be solved in the design of the RFQ linac.
We have adopted a "folded coaxial" RFQ (FC-RFQ)
structure,2) because it allows the cavity to be tunable
in a wide range of frequencies and to be compact evenin the low frequency region below 20 MHz. The FCRFQ structure can also enables the intervane voltage
to be flat enough to obtain high beam-transmission
efficiency. A half-scaled model for the cold test wascompleted at the end of the last year and the measurements showed that the model had good performancein accordance with the design. The power losses are
expected to be 6 kW at 17 MHz and 34 kW at 35 MHz.
The beam transport system between the ECR ion
source and the FC-RFQ linac consists of an Einzellens,
a 90° bending magnet, and a solenoid magnet. This
combination enables it to analyze beams with different
m/ q's and match the emittance of a selected beam tothe acceptance of the FC-RFQ linac. Beam diagnostic

163

devices such as a Faraday cup, a beam profile monitor,
and a beam emittance monitor will also be installed.
The new injector system is now being fabricated at
the factory of SHI (Sumitomo Heavy Industries, Ltd)for completion by the spring of the next year. The
beam test will be made at RIKEN before the installation on the due site of RILAC.

164

References
1) T. Nakagawa et al.: This report, p. 165.
2) O. Kamigaito et al.: This report, p. 168; O. Kamigaito,
A. Goto, Y. Miyazawa, T. Chiba, M. Hemmi, M. Kase,and Y. Yano: Jpn. J. Appl. Phys., 33, L537 (1994).
3) N. Inabe et al.: This report, p. 166.
4) T. Nakagawa et al.: Jpn. J. Appl. Phys., 32, L1335(1993).

RIKEN Accel. Prog. Rep. 28 (1995)

Design of RIKEN 18 GHz Electron Cyclotron ResonanceIon Source (ECRIS)
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
To increase the beam intensity of heavy ions accelerated by RILAC,l) we have designed a new 18 GHzECRIS. A schematic overview of the ECRIS is shownin Fig. 1.

118 GHz RIKEN ECRIS I

TMP 1501/s

Fig. 1. Schematic drawing of the 18 G Hz ECRIS andtypical magnetic field distribution.

The axial confinement of the plasma is obtained by
two solenoid coils which provide a magnetic mirror.
The source is completely enclosed by an iron york inorder to reduce the current of solenoid coils. The expected power consumption is about 90 kW. The coils
are independently powered.
The mirror ratio has a nominal value of 2.7. In orderto optimize the magnetic confinement of the plasma,
we used the hexapole magnet structure proposed by
Halbach. 2) The hexapole magnet consists of 24 segments made of Nd-Fe-B permanent magnets. The
outer diameter (OD) and inner diameter (ID) are 180
and 80 mm, respectively. All of the segments are
made of a material with high coercitivity (NEOMAX40 Sumitomo Special Metals Co., LTD.). The designof the magnetic structure has been optimized by using

the computer code PANDIRA. The field strength at
the surface of the magnet is about 1.4 T. To protect thehexapole magnet from demagnetization by high temperature, a water cooled plasma-chamber with ID = 75
mm OD = 80 mm has been constructed. The watercooled haxapole housing protects the permanent magnet from the high temperature caused by the solenoids.
We have chosen a microwave frequency of 18 GHz
because it is the highest frequency that can be obatinedby a commercially available klystron tube and applied for 2 Wee (electron cyclotron resonance frequency)mode operation.
The high vacuum of the plasma chamber is very important to produce the intense beam of highly charged
ions. 3 ) This may be due to the effect of recombinationof the ions. In the case of 18 GHz ECRIS, the plasmachamber is evacuated with the 500 and 150 lis turbo
molecular pumps. Using this pumping system, the ultimate vacuum of the plasma chamber will be of theorder of 10- 8 Torr.
In order to produce the highly charged ions fromsolid materials, the matrials are directly inserted into
the plasma axially using a same method as describedin Ref. 4.
To inject heavy ions into RILAC from the ECRIS,
it will be connected with a new type variable energyRFQ5) which is designed as an injector for RILAC.
References
1) M. Odera et al.: Nucl. Instrum. Methods, 227, 187(1984).
2) K. Halbach: ibid., 187, 109 (1981).
3) T. Nakagawa, T. Kageyama, M. Kase, A. Goto, and Y.
Yano: Jpn. J. Appl. Phys., 32, 1335 (1993).
4) E. Ikezawa et al.: Proc. 8th Symp. on Accelerator Science and Technology, 1991, Saitama, p. 73 (1991).
5) O. Kamigaito et al.: This report, p. 168.

165

RIKEN Accel. Prog. Rep. 28 (1995)

Design of a Beam Transport Line between the 18 GHzECRIS and the RFQ Linac
N. Inabe, M. Kase, O. Kamigaito, Y. Miyazawa, M. Hemmi, T. Chiba,
A. Goto, Y. Batygin, and Y. Yano
We designed a beam transport line between 18 GHz
ECR ion source l ) and RFQ linac (RFQ)2) that will be
newly installed as a pre-injector of the RILAC. Figure
1 shows the transport line. In the design we required
two conditions for the transportation of the beam. One
is to separate a beam from the other unnecessary particles from the ion source and another is to matchthe emittance of the beam to the acceptance of the
RFQ. From the conditions we separated the transportline into two sections: a beam analyzing section and amatching section. The beam analyzing section consistsof a dipole magnet and drift spaces before and after it.
In the section the end point is the analyzing point of
the beam. The matching section consists of solenoid
and drift spaces before and after it. The entrance ofthe section is the analyzing point and the exit the entrance of the RFQ. As shown in Fig. 1 the transportline has a beam diagnostic system such as a profile
monitor, slits, and a Faraday cup around the analyzing point. Two vacuum pumps (350 lis) are used. The
designed vacuum pressure is less than 10- 7 Torr.

Matching
Section- + - - - - - - Analysing
SectionR

the starting point of the analyzing section, since using
another computer simulation code we confirmed thatthe shape of the emittance at this object point could
be made to be the same as that from the ion source bylocating an einzel lens after the ion source. The maximum magnetic rigidity was taken to be 76.13 kG*cm,
which is the same as the designed value for the RFQ.
In the cal-culation we did not take account of the spacecharge effect.
The parameters of the analyzing section such as
drift lengths and edge angles of the dipole magnet
were searched under the conditions of mass separation (M/ LlM) > 100 and double focus at the analyzing
point. For the dipole magnet we chose the same size
as for the analyzing magnet between the 10 GHz ECRion source and the AVF cyclotron (500 mm in radius,
80 mm in gap and 90° in bending angle). The reason
for the choice is that the both maximum rigidities are
similar to each other.
The parameters of the matching section such as
strength and effective length of the solenoid and drift
lengths were searched under the condition that thephase ellipses for the beam in both horizontal and vertical directions of the beam should lie into those of acceptance of the RFQ. As an additional condition weTable 1. Designed parameters of the components in the
beam transport line.
Distances
Object point rv
entrance of the dipole magnet
Exit of the dipole magnet rv
analyzing point
Analyzing point rv
entrance of the solenoid
Exit of the solenoid rv
entrance of the RFQ linac

Fig. 1. Schematic drawing of the beam transport line
between the 18 GHz ECR ion source and the RFQ linac.

For the search of the parameters such as drift lengths
and strength of the solenoid we used the computer code
TRANSPORT. The properties of the beam such as
emittance, dispersion, and size was calculated by thecode. In the calculation the emittance of the beam at
the exit of the ion source was assumed to be a standard ellipse of 11"*5 mm*29.0 mrad and the momentum
spread, Llp/p, to be O. The half width of the beam of 5
mm corresponds to the radius of the extraction hole ofthe ion source. The object of the optics was chosen at
166

Magnets
DipoleRadius
Bending angle
Maximum magnetic field
Edge angle (entrance and exit)
Gap
Solenoid
Inner radius
Outer radius
Effective length
Real length
Maximum magnetic field

1.1 m
1.1 m
1.0 m
0.37 m

0.5 m
90.0°
1.6 kG
28.7°
80mm
45mm
305 mm0.25 m0.31 m
6.3 kGrequired that the total lengths of the section should be
as short as possible. The reason to choose the solenoid
as a matching element is that the phase ellipses of thebeam in the horizontal and vertical directions are similar at the entrance of the section and that the RFQ
has the same acceptance in the both directions. Moreover it was because choice of the solenoid led the section to be compact. The magnetic field of the solenoid
was calculated by the computer code POISSON. Fromthe calculation we determined the real length of thesolenoid for the required effective length and strength.
From the search we obtained the parameters of thetransport line. The parameters are summarized in Table 1. The maximum designed fields of the dipole magnet and the solenoid have 10 rv 20% margin of therequired maximum fields.

Figure 2 shows the envelope of the whole transport
line. It is shown that the clearance of the beam for each
aperture is large enough. The dispersion and magnification in the horizontal direction at the analyzing pointare 2.20%/cm and -0.98, respectively. From the values of dispersion and magnification, M/ ~M is about
200 and it is large enough for the required one. Figure
3 shows the phase ellipses of the beam in the horizontal and vertical directions and the acceptance of the
RFQ. As shown in Fig. 3, the ellipses of the beam arewrapped in those of acceptance of the RFQ and thematching between the emittance of the beam and theacceptance of the RFQ is very good.

(mrad)
100
(cm)
(ij

DipoleSolenoidb)Vertical phase ellipse(mrad) , - - - - - -- - - ,
100

50

OJ

0

lij 0

ctI

C 4
0
N
.§ 3
I
2

50

Q)

Q)

g>

6
5

a)
Horizontal phase ellipse

-50

-50

-100

-100
-5 .0

1

-2.5 0 2.5
position

5.0(mm)

of eam
-5.0-2.5 0 2.5
position

5.0(mm)

0 -+-_-I---!_ _+-_.j.....j.-~ Entrance of

the RFQ linac

1

ro 2

,g

3

iii
> 4
5
6

Fig. 3. Phase ellipses of emittance of the beam and theacceptance of the RFQ linac at the entrance of the RFQ
linac: a) in the horizontal direction and b) in the vertical one.

Analysing point

References
Fig. 2. Calculated envelope of the beam from the ECR
ion source to the RFQ linac.

1) T. Nakagawa et al.: This report, p. 165.
2) O. Kamigaito et al.: This report, p. 168.

167

RIKEN Accel. Prog. Rep. 28 (1995)

Cold Model Test of the Variable Frequency RFQ Resonatoro. Kamigaito, A. Goto, Y. Miyazawa, T. Chiba, M. Hemmi, s. Kohara, M. Kase, and Y. Yano
Cold model test of the resonator of the variable frequency RFQ linac, designed as a new injector for RILAC, has been performed. This RFQ will accelerateions with a range of M/q = 7- 28 to the final energyof 450 ke V / q in the cw mode, by varying the operational frequency from 17 MHz to 38 MHz. With the 18
GHz-ECRIS,l) the RFQ injector is expected to greatly
increase the intensity of the heavy ion beams for RILAC in the near future.
The RFQ resonator is based on the "folded-coaxial(FC)" structure. 2 ) This RFQ has the following distinct
advantages. Firstly, the resonator can be made very
compact even in the low frequency region below 20
MHz. Secondly, the operational frequency is changed
widely with a movable shorting plate. Thirdly, theintervane voltage can be made flat enough to obtainhigh beam-transmission efficiency.
Figure 1 shows a schematic drawing of the RFQ resonator. Horizontal vanes are held by front and rear
supports fixed on the base plate. Vertical vanes are
fixed on the inner surfaces of a rectangular tube whichsurrounds the horizontal vanes. This tube is supported
by four ceramic pillars placed on the base plate. A
stem suspended from the ceiling plate is in electricalcontact with the rectangular tube. A shorting plate
placed around the stem can be moved vertically, which
varies the resonant frequency. Radio-frequency poweris fed into the resonator through the side wall by acapacitive feeder. A capacitive tuner is set on the opposite side wall and two capacitive pickup monitors are
set on the base plate.
The resonator is separable into upper and lower
parts, as shown in Fig. 1. The horizontal vanes andFig. 1. Schematic drawing of the RFQ resonator. The
size of the half-scale model is about 850 mm (L) x 350
mm (W) x 500 mm (H).

168

the rectangular tube with the vertical vanes are rigidly
fixed inside the lower part. The upper part containing the stem and the shorting plate can be removed
as an unit. This separable structure permits accuratealignment of the vanes and easy maintenance.
Figure 2 shows the schematic drawing of the magnetic flux of the fundamental mode. The flux surrounds the stem, rectangular tube and the horizontal
vanes. The direction of the flux is reversed at the middle of the vanes, and the magnetic field vanishes there.

Stem

Vertical Vane

Movable Shorting Plate

Stem

Lower Stem

Fig. 2. Schematic drawing of the magnetic flux of thefundamental mode of the RFQ resonator. The lower
stem is installed only in the high frequency operation.

In order to investigate the rf characteristics of theresonator, a half-scale model has been made of copper(CIlOO). The fabrication procedure for the real· RFQ
linac was also studied in the design of the model resonator. In the initial measurements, the vanes having
a constant bore radius and the ceramic pillars made ofMacor were used. The vanes have been aligned within
the accuracy of 30 j.tm.
Figure 3 shows the measured resonant frequency of
the fundamental mode along with the calculated values
using the computer code MAFIA. The resonant frequency varies from 34.0 to 70.0 MHz by changing theposition of the shorting plate by a stroke of 330 mm,
which means that the actual operational frequency will
range from 17.0 to 35.0 MHz. The resonant frequencies of the higher modes appear over 200 MHz, well
separated from that of the fundamental mode.
Figure 4 shows the measured Q-values and the shunt
impedances of the fundamental mode. The MAFIA
calculations are also shown in the figure. The calculation overestimates the measured values by 30-50%.
This is considered to result from the fact that the calculation does not realistically treat the roughness of
the wall surface and the imperfectness of the electriccontact. From these measurements, the power lossesof the real RFQ linac are expected to be 6 k W at 17
MHz and 34 kW at 35 MHz.

80

•

70

Calc.

e

N
I

Meas.

60

~
&
Q)

•
•

u: 50

•
• •

40

30

100

0

•

200

• •
400

300

L(mm)

Fig. 3. Measured resonant frequencies (closed circles) andthe values calculated using MAFIA (solid line) of thefundamental mode for the half-scale model. L denotes
the distance in mm between the top surface of the rectangular tube and the bottom surface of the movable
shorting plate.

The modulated vanes have been fabricated by using
the NC ball-end-mill machine within the accuracy of
30 Mm. The resonant frequencies have risen up by
about 1% and little change has been found in the
Q-values and the shunt impedances. Ceramic materials were also examined by measuring the Q-values
with pillars made of several types of Ah03 and AIN
being installed. At the present, ceramic pillars ofAh03(Kyocera A479) are to be used in the real RFQ
linac .
If we install an additional stem as shown in Fig.
2, the power losses can be reduced in the high frequency region above 35 MHz because the rf electric
current is shared by the two stems. This lower stem
is installed only in the high frequency operation. We
have installed two kinds of lower stem in the half-scalemodel and measured the Q-values. As shown in Fig. 5,
the operational frequency is restricted in the high frequency region but the Q-values are larger than those
only with the upper stem. This result shows that theoperational frequency can be extended to 38 MHz withthe power loss of 34 kW.

4000
7000
Q-value
6000
5000
4000
3000
2000
1000
80
70
60
50
40
•
30
• •
20
•
•
10 •
0
0
100

~"

0

()

0

(;

(J

0

1

Upper Only

0

3000

Round 100·phi

:::~

~.)

Q)

::J

co

a>
2000

• •

• •

•
Calc .

oe Meas.

200

300

100~0

40

50

60

70

80

90

Freq. (MHz)

400

L(mm)

Fig. 4. Measured Q-values (open circles) and the shunt
impedances (closed circles) of the half-scale model. The
solid lines indicate the MAFIA calculations.

The intervane voltage distributions along the acceleration axis were measured with a perturbation
method. They were found to be in good agreementwith the MAFIA calculations. The imbalance among
the intervane voltages in the four quadrants was ±2%
at most.
Next, we replaced the un-modulated vanes withmodulated ones and measured the rf characteristics.

Fig. 5. Measured Q-values of the half-scale model of the
RFQ resonator. The triangles are the Q-values using
only the upper stem. The rectangles and the circles are
the ones using lower stems of different shapes.

The design of the real RFQ linac is under progressby taking these results into account.
References
1) T. Nakagawa et al.: This report, p. 165.
2) O. Kamigaito, A. Goto, Y. Miyazawa, T. Chiba, M.
Hemmi, M. Kase, and Y. Yano: lpn. l. Appl. Phys.,
33, L537 (1994).

169

RIKEN Accel. Prog. Rep. 28 (1995)

Hollow Beam Formation in the Extraction Region of ECRIS
Y. Batygin, A. Goto, and Y. Yano
Beam quality of a heavy ion accelerator complex ismostly defined by the extraction region of ion source
where a space charge and a nonlinear external focusing
field are essential. The extraction region of the 18 GHz
ECR ion source which is under construction to upgrade
RIKEN Accelerator Research Facility consists of an
extraction electrode under the voltage of U ext = 10k V followed by a three-electrode Einzel lens (see Fig.
1). After passing the lens, the beam has to be focused
into a spot with a diameter of 10 mm to be matchedwith the following transport system.

where k = 8.617 X 10- 5 eV·K- 1 is Boltzmann's constant and WL = qB/2m is Larmor's frequency. For theconsidered case of the 18 GHz ECR ion source theresonant value of magnetic field is B = 0.637 T. The
normalized beam emittance of an Ar+ 5 beam with thetemperature kTi = 3 eV is:
E= 2x5xl0- 3 xVO.8 x 10- 10 + 10- 9= 3.3 X 10- 7 11" m rad.

(3)

The beam emittance is mostly defined by the value ofmagnetic field.
Particle trajectories obey the equations of motion
derived from a single particle Hamiltonian:4~--------4---+-~--4---------~

2~~====~--~--~======~
~o
><

60

20
Z,CK

Fig. 1. Particle trajectories in the extraction region of the
18 GHz ECR ion source.

where Pn Pe and pz are components of momentum of
the particle, U f is a potential of the focusing field, U c
is a space charge potential of the beam and Ae = Br /2
is a vector potential of the magnetic field. From computer simulation of the beam extraction problem in the
ECR ion source it follows that the beam can obtainhollow structure in the time of crossover (see Fig. 2).
The same phenomenon was observed in high perveance
electron guns 3) and under focusing of an electron beam

Numerical calculation of beam extraction was performed with the computer program BEAMPATH. 1)
Ion trajectories start from a concave plasma emitting
surface within the beam convergence angle 8 definedby an aspect ratio R/ d of extraction region and a ratio
of beam perveance P = I/U ext 3/2 to Child-Langmuir
perveance Po = (411" /9)Eo(R2 /d 2)(2q/m)1/2 of one dimensional diode: 2)

o= -O.625~

(:0

1.5

1.0

0.5

~ 0,0

):."

-0.5

-1.0

-1).

(1)

1.5

-1.5
-1.5

-I

-0.6

0

0.5

1.5

X.C11

For the expected value of beam current I = 100 /-LAof Ar+ 5 the flow of particles is not space charge dominated and therefore initial convergence of the beam
8 = - 0.075 is mostly defined by the focusing properties of extraction region.
The value of normalized beam emittance E is definedby the magnetic field fulfilling the ECR resonance condition 2WL = WRF and ion temperature T i due to ionization processes in plasma:0.00020.0001t---t--+--+--+---+-----1~ 0 .0000-0.0001

0.0001~ 0.0000I--+--+--+-+---+----l-0.0001

X.C11

2

E=2R

170

kTi + [WLR]-mc-2 c '
2(2)

Fig. 2. Cross section of the beam (top) and phase space
projections of particles (bottom) at z = 16 cm (leftcolumn) and at z = 60 cm (right column).

by short solenoid lenses with large aberrations. 4 ) For
more details, let us consider the following analyticalmodel.
The particles are born in the magnetic field of ECR
ion source, hence every particle has non-zero value of
azimuthal component of canonical momentum:(5)
After the solenoid the particles pass through the focusing lens and then move in a drift space. · Electricfield of the lens provides focusing which consists of alinear term G and higher order terms. We restrict ourconsideration to the first nonlinear term of electric field
G 3 . The transverse equation of motion of a particle inthis region is given by

We assume the thin lens approximation which meansthat the length of the lens is small in comparison to
the focal length. Therefore the radius of particle rois not changed during the time of passing through thelens tl' Equation (6) can be integrated to obtain therelationship between the initial and the final radii ofparticle in the drift region:(7)
where T = WL t is a dimensionless time of particle drift
and the following notations are used:(8)

To find the beam density redistribution let us assume
that the number of particles dN inside a thin ring(r, r + dr) is constant during the drift of the beam,hence the particle density p(r) = dN/(27rrdr) at any z
is connected with the initial density p(ro) by the equa-tion p(r)dr2 = p(ro)dr6 or:

From this relationship it follows that changing of thebeam profile is observed when a nonlinear term of the
focusing field is not zero (8 to). The linear focusinglens (8 = 0) conserves the beam profile and changes
only sizes of the beam. Introducing the nonlinear component of focusing field results in beam intensity redistribution according to the above formula and finally inhollow beam formation.
The hollow beam profile formation can be understood from the fact that spherical aberration of anelectrostatic lens always increases focusing of particles
in comparison with the ideal linear focusing. 5 ) As asequence the peripheral particles in the drift region
move faster to the axis than the inner beam particles.
It results in a most populated boundary of the compressed beam than the core of the beam at the pointof crossover.
Hollow beam formation is accompanied by emittance
growth of the beam due to nonlinearity of a focusinglens. In the considered case the effective root-meansquare emittance(10)
is increased by 1.3 times (see Fig. 2). For keeping thequality of the beam obtained from an ion source thenonlinearity of the focusing lenses have to be minimized.
References
1) Y. Batygin: Proc. EPAC92, Berlin, p. 822 (1992).
2) J. Kim, J. Whealton, and G. Schiling: J. Appl. Phys.,49, 517 (1978).
3) M. Reiser: Theory and Design of Charged Particle
Beams, Wiley, New York (1994).
4) P. Loschialpo et al.: J. Appl. Phys., 57, 10 (1985).
5) J. D. Lawson: The Physics of Charged Particle Beams,
Clarendon Press, Oxford (1977).

171

RIKEN Accel. Prog. Rep. 28 (1995)

Beam Dynamics Study in Variable Frequency
RFQ Linac for RILAC
Y. Batygin, A. Goto, O. Kamigaito, and Y. Yano
An RFQ linac is characterized by the high transmission efficiency of particles and a large value of transversal acceptance which allows us to use it for accelerationof charged particle beams with high current and low
initial energy. The RFQ structure designed for upgrading the RIKEN Linear Accelerator (RILAC)l) is
aimed to accelerat e ions in a large range of charge tomass q/m ratio. Acceleration of different kinds of ionsin the structure with a given value of intervane voltage
U is performed by the change of operational frequency
f and energy W of the beam fulfilling the conditionsof invariance of acceleration gradient and geometry of
the channel:

vw const· mqUf2

-

f

- =

'

= const.

(1)

Latest study of H- beam dynamics in Ground Test
Accelerator 2) under a space charge dominated regime
shows that the transmission efficiency observed in experiment was significantly lower than it was expectedfrom calculations (73% instead of 90% under the beam
current of 37 mA). Possible sources for it were foundto be higher order terms in RFQ potential and image charges. The purpose of this work is to examine
how the transmission efficiency and other beam parameters are influenced by different representation of
the designed RFQ field in the case of two lowest-order
RFQ terms both neglecting space charge and undera high value of beam current including image forces.
Multipole effects of RFQ potential can be investigatedafter choice of an exact shape of electrodes.
Beam dynamics in RFQ accelerator is studied using the general-purpose particle-in-cell code
BEAMPATH.3 ) The beam is represented as a collection of a large number of modeling particles (macro
particles). The problem is solved in a right-handCartesian coordinate system (xyz). Particle trajectories obey the equations of motion followed from a single
particle Hamiltonian:(2)

method is used:
PISTEP+l/2 = PISTEP - l/2
rIsTEP+l = rIsTEP+ EISTEP * DT

+ VISTEP+l/2 * DT.

(3)

The electric potential of the RFQ structure is givenby the expression: 4 )• sin(27rft + <Po)

(4)

where X and T are focusing and acceleration efficiency
respectively, and k = 27r / (3).. is a wave number.
Space charge field of the beam is calculated at eachtime step from the Poisson's equation in the system of
coordinates, moving with the bunch:p(x, y , z)

(5)

The Dirichlet boundary conditions for potential Uc areimposed on the surface of an infinite pipe and periodic conditions in longitudinal direction are assumed.
The region occupied by the bunch of particles is divided into uniform rectangular meshes of dimension
NX·NY·NZ. Charge of every particle is distributed
among the nearest eight nodes inversely proportional
to the distance from particle to each node. For obtaining a solution of Poisson's equation the space charge
density of the beam and unknown potential functions
are represented as Fourier series:
NX-l NY-l N2z-1

U ijk =_

~ ~ ~ {[u~1wcos C~~k)w.

+ U uvw sm (27rWk)]
NZ• sin (7rUi)
NX . sin (7rVj)
NY } (6)analogously for p (x,y,z) . Calculation of series (6)is performed using the Fast Fourier Transformation(FFT) method. Space charge and potential expansion
coefficients are connected by an algebraic relationshipfollowed from Poisson's equation:

where p = (Px , Py , pz) is a momentum of the particle,r = (x, y , z) is a radius-vector of the particle, U RFQ is apotential of the radio frequency quadrupole structure,U c is a space charge potential of the beam. For inte-

gration of the equations of motion the second order172

which gives the solution of the space charge problem.
Parameters of the numerical model used in simulation

Table 1. Parameters of the numerical model.
Number of macroparticles
Spatial grid NX·NY·NZ
CPU storage requirement
Integration step DT·f
Total number of integration steps
CPU time (for VAX Alpha):
1= 0
1= 1 rnA

104
64 x 64 x 256
8 MBt
1/40
1600
10 min.
535 min.

are listed in Table 1.
Four different types of RFQ field representation werecompared in calculations: (i) linear variation of acceleration efficiency T, focusing efficiency X and apertureof the channel a along the structure (PARMTEQ type field 5 )); (ii) a step-wise function of above parameters assuming the values of (ai) = O.5(ai-l + ai)
and (Ti) = 0.5(T i- 1 + T i) equal to mean values overeach cell; (iii) a step-wise function of parameters assuming the values of (ai) = 0.5(ai-l + ai) andTable 2. Beam parameters in RFQ structure. (A/Z = 5, f = 40 MHz)RFQ field approximation:

Linear(PARMTEQ-type)
1=0
1= 1 rnA

Step-wise((ai),(Ti))
1=0 1=1 rnA

Step-wise((ai),(mi) )1=0 1=1 rnA

Step-wise(Ti,Xi,ai)
1=0 1=1 rnATransmission efficiency,
Initial emittance 1r mm mrad
Final emittance, 1r mm mrad
Energy spread dW /W
Bunch length

0.94
0.3
0.36
0.034
36°

0.94
0.3
0.35
0.034
30°

0.92
0.3
0.39
0.034
31 °

0.86
0.3
0.42
0.023
50°

0.87
0.3
0.40
0.023
28°

(mi) = 0.5(mi-l + mi) equal to mean values over eachcell; (iv) a step-wise function assuming all parameters
are equal to the designed values at the end of each cell
Til Xi, ai·
In Table 2 the results of simulation of the beam with
A/Z = 5 are presented. The value of transmission efficiency obtained with a linear change of RFQ field along
the structure agrees well with PARMTEQ prediction(94 % for zero beam current and 90% for I = 1 rnA).
The step function of RFQ field representation gives
smaller values of transmission efficiency especially forthe space charge dominated regime.
Most of the particle losses are observed in transverse directions in the region between buncher and accelerating section. This region is characterized by a
sharp increase of electrode modulation which results ina quick change of acceleration gradient along the structure and non adiabatic oscillation of particles. Smallchanges of parameters T, X due to different representation of RFQ field results in deviation in synchronous

0.86
0.3
0.39
0.025
30°

0.78
0.3
0.44
0.024
24°

0.70
0.3
0.45
0.018
38°

phase of the bunch and mismatch of the beam withthe channel. Beam losses in the longitudinal direction
are much smaller (typically 2% for zero beam current
and 4% for beam current I = 1 rnA).
Further optimization of the acceleration structure isrequired to improve the beam transmission efficiency
and to reduce the transverse beam emittance growthin RFQ linac.
References
1) O. Kamigaito et al.: This report, p. 168.
2) O. R. Sander et al.: Performance Report on the
Ground Test Accelerator RFQ, presented at LINAC94,
Tsukuba, Abstracts of LINAC94, p. 69 (1994).
3) Y. Batygin: Proc. EPAC92, Berlin, F.R.G., p. 822(1992).
4) I. M. Kapchinsky: Theory of Resonance Linear Accelerators, Harwood, New York, U.S.A. (1985).
5) PARMTEQ code, Los Alamos National Laboratory.

173

RIKEN Accel. Prog. Rep. 28 (1995)

Construction of the RIKEN-RAL Muon Facility
K. Nagamine, T. Matsuzaki, K. Ishida, I. Watanabe, and R. Kadono
The construction of the RIKEN muon facility at
Rutherford Appleton Laboratory (RAL) which wasstarted in 1990 came to the final completion stage atthe end of 1993. The first beam is scheduled in the fallof 1994. t
The rapid-cycling, high intensity proton synchrotronof the ISIS accelerator of Rutherford Appleton Laboratory (RAL), which was constructed for a spallation
neutron source, is most suited for the pulsed muon generation. The ISIS can produce 800 MeV protons in a
double pulse time structure (70 ns width, 340 ns separation and 50 Hz repetition) at an average current of
170 j.LA.

The final form of the RIKEN-RAL muon facility isshown in Fig. 1 which is almost identical to the original

design proposed in 1990. The high intensity protons
which have the double pulse time structure produce
pions which are, after momentum selection, injected
into a 5.5 m long, 12 cm bore and 5 T superconducting solenoid. During the passage in the solenoid field,
intense pulsed muons are produced via pion decay inflight. The double pulse structure of the muons whichis inconvenient to most of the muon science experiments is changed into two beams of a single pulse structure by a magnetic kicker system, each of which is fed
into a separate experimental part (port 3 and port 1
or port 2).
In the fall of 1993, the superconducting solenoid andassociated supercritical He cooling system was completed at the final location of the site. As described
separately, the pulsed magnetic kicker system was completed in March 1994. The rest of the facility inculding
the septum magnet placed after the kicker, dc separator, etc. were all completed in the spring of 1994. Various installation works including services and cablings
will be completed in the summer of 1994.
The expected muon intensity is shown in Fig. 2,
showing the world strongest pulsed muon facility to
be realized at the RIKEN-RAL muon facility.

(b)
1o~.---------,;.):t104~-----f:i:::l--f::E:[£? I 03r-:-----i:i~~

-

+-'

Cd

~ 102t-----~~~
c:::l

r--

~ 1U't-----~~~........

I-

~

3

I0

I

LAMPI' TRIUMF RIKEN/RAL
PSI
KEK

<fl

g10°

::E

\0' '--'"...........---""--""''''--'"''"'--'LAMPF TRIUMF RIKENIRAL
PSI
KEK

Fig. 2. Comparison of muon intencity at world-wide facilities; (a) average integrated intensity per sec and (b)instanteneous muon intensity.
Fig. 1. Schematic layout of RIKEN muon facility at RAL.

Note added in proof. The first beam was successfully generated on Nov. 9, 1994 with a confirmation of the achievementof expected intensity and quality.

174

RIKEN Accel. Prog. Rep. 28 (1995)

Optics Design for the RIKEN-RAL Muon Channel
K. Ishida, K. Nagamine, T. Matsuzaki, 1. Watanabe, and G. H. Eaton*
RIKEN is constructing a high intensity pulsed muon
beam channel at the ISIS facility of Rutherford Appleton Laboratory (RAL). 1) There, a rapid cycle proton
syncrotron (800 MeV, 50 Hz) of high intensity (200/-LA) has been used mainly for a spallation neutron
source. Our muon channel will take the pions generated from the intermediate target placed upstreamof the main target. As the best beam channel forthe negative muon production, we have adopted thebeam channel with a decay section of super conducting
solenoid like PSI or UTMSLjKEK. 2 ,3)The muon beam channel consists of four main parts,
namely, a pion production target, a pion injection system, a solenoid decay section, and a muon extraction
system. Muons will be delivered to two of the threeexperimental ports simultaneously (port 3 and port 1
or port 2).1)(1) The pion production target is a 10 mm thickgraphite. The number of generated pions N7r is expressed as

N7r = Nc x Ip X d 2 (J' jdOdp x LlO Llp
Ip = 1.25 X 10 15 jsec (200 /-LA)
Nc = 6 X 10 23 jmol j 12 gjmol x 2.25 gjcm 2= 1.12 x 10 23 jcm 2(10 mm = 2.25 gjcm 2
thick carbon target)d 2 (J' jdOdp = (d 2 (J' jdOdE7r ) ( dE7rjdp) ,where Ip is the proton beam intensity, Nc is the number of carbon nuclei in the target, and d 2 (J' jdOdE7r
is the differential pion production cross section at 90
degrees to the proton beam. The pion production
cross section was taken from the data of LAMPF (730
Me V). 4) Some enhancement of the cross section may
be expected at 800 MeV. Typical number of generated
pions was estimated to be 1.3 x 108 jsec in a phasespace of 100 mr x 100 mr and a momentum width of
121 MeV jc ± 5%.
(2) The pion injection system consists of two
quadrupoles and a bending magnet to select the pion
momentum. It is designed to have an acceptance of
LlO = 75 msr and Llp = 10%.
(3) In the solenoid decay section the solenoid is used
for confining the muons produced from the decay ofthe pions in the solenoid. The muons may be produced
in any direction and at any place along the solenoid.
With the help of the solenoid, the exit of the solenoid
can be considered as a muon source.
(4) The muon extraction system is essentiallya QQQ-B-QQQ-B-QQQ system, where Q is aquadrupole magnet and B a bending magnet. In Fig. 1

is shown the typical beam envelope in the muon extraction system for port 2. Each triplet quadrupole works
as a lens, and the bending magnets are placed at the
two nodes. Additionally, a kicker system 5 ) is placed in
the straight section after the first triplet (QQQ). Also
two DC separators with cross field coils were installed
to remove positrons and electrons in the beam.
~

~

N

a:

a:

0

0

~

&l 8> d o~

""

u

:;z

0

~

~

a:

~~

~ :§t;.~~

o

V>

~

30&

m

O'l

::J

~

E 24

~ 20
~

16

~ 12
~ 8

§?

]:
...J

~
ffi
~

12

./

~

'"

r--

-

t'-

,,/y

- . . . . . r--.

~i'-

r-V

1-)"""-

~""

, ,

16

\
/
!
\

> 20

I

24

Fig. 1. Beam envelope in the extraction system for port 2.
The initial phase ellipse is ~x = ±30 mm, ~x' = ±80
mr, ~y = ±20 mm, ~y' = ±80 mr, ~p = ±5%.

The expected intensities of the muon beam for various momenta were calculated and are shown in Fig. 2.
The first muon beam was succesfully produced in 9th
November of 1994. A detailed beam tuning is now inprogress.

~

107

>Vi

106

(zl

10 5

_... - - - - - -~[-Decay J.1"

z

[-

~

z
0

:::>
;:;;:

10'

0

(zl

[-

«:
;:;;:

10 3

§::

en

(zl

10 2

M

W

W

~

1M

MUON MOMENTUM [MeV/ c ]Fig. 2. Expected muon beam intensity for the RIKEN
Muon Channel.

References
1) K. Nagamine et al.: This report, p. 174.
2) G . Vecsey: SIN Report, PR-75-002 (1973).
3) K. Nagamine: Hyperfine Interact., 8 , 787 (1981).
4) D. R. F. Cochran et al.: Phys. Rev. , D6, 3085 (1972).
5) I. Watanabe et al.: This report, p. 176.

Rutherford Appleton Laboratory

175

RIKEN Accel. Prog. Rep. 28 (1995)

Development of a Pulsed Kicker Magnet for the RIKEN-RAL
Muon Beam Line
1. Watanabe, K. Ishida, T. Matsuzaki, K. Nagamine, and E. G. SandelsA RIKEN Muon Beam Facility is being constructed
at Rutherford-Appleton Laboratory (RAL) in UK.1)
Intense double pulsed muon beams which have wide
momentum from 20 MeV Ic to 120 MeV Ic will become
available at the new RIKEN facility. The separation of
the double pulse is about 340 nsec from peak to peak
and the width of each single pulse is about 70 nsec withthe repetition rate of 50 Hz. The RIKEN muon facility
consists of a pion injection system, a superconducting
solenoid magnet, a muon extraction system and threemuon experimental areas.!) A fast pulsed kicker magnet is installed in the muon extraction system. In caseof the low momentum beam, the double pulsed muon
beam is separated by the kicker magnet and each single
muon pulse is delivered to the two muon experimental areas simultaneously. The first muon pulse passes
through the kicker magnet without magnetic field andthe second pulse is deflected by the kicker magnetic
field. To achieve a good separation of the muon pulse,
the kicker magnetic field should be established within
250 nsec pulse separation time by the pulsed high current. In this paper the development of the fast kicker
magnet is reported.
Figure 1 shows the electrical circuit of the kicker
system. The kicker system consists of a PFN circuit,a fast switching thyratron, power cables and the magnet. The PFN circuit consists of 18 sections of the
combination of capacitors and coils, and has a characteristic impedance of 6.73 O. The 7-coaxial cables with
50 0 impedance are used in parallel. The thyratron is
CX1725A (EEV, UK), and has a standing voltage of
70 k V. Both of the PFN circuit and the thyratron arecooled by air. The PFN is discharged by the thyratron. When the discharged pulse comes into the magnet, the reflection of the pulsed voltage occurs at themagnet end because of the magnet inductance resulting in the doubling of the voltage at the coil. This reflection causes the doubling of the current which passes
through the magnet coil. This is the advantage of thiscircuit system compared with the impedance matching type system. The discharge current comes into themagnet through the sheath of the power cable and thereturn current from the magnet comes into the PFN
through the inner conductor of the power cable andis absorbed in a dump resistor at the other side of the
PFN circuit. The dump resister is soaked in oil and theoil is cooled by water through a heat exchanger. Since
any additional inductance in the circuit would increase
the rise time of the kicker magnetic field , these inductance should be minimized. For instance, the cathodeof the thyratron is earthed to reduce the floating inductance around thyratron as shown in Fig. l.
The kicker magnet consists of four unit magnets ofthe same structure. 2 ) Figure 2 shows the unit kicker
magnet. The unit magnet is made of ferrite pieces of
40 mm thickness, and designed to be a "C"-type structure. The aperture of the unit magnet is 250L x 200H(mm) and the length along the beam line is 200 mm.
The total length of the kicker magnet is 800 mm. A
single turn coil made of pure Cu plate is wound arounda ferrite core. All of the ferrite pieces are supported
directly and individually by ceramic supports. The
outside surface of the ferrite core is covered by a thinCu plate to prevent the leakage of the magnetic fieldwith the help of the eddy current in the Cu plate. A
thick Cu plate (Mirror Plate) is installed at the openside of the "C" -type structure to prevent the leakage
field and to homogenize the magnetic field. 2) Some capacitors are installed in parallel to the magnet coil asshown in Figs. 1 and 2.2) The rise time of the magnetic field is improved because of the over shoot of thedischarge current which is due to the impedance mismatch of these capacitors in the magnet. The main
parameters of the kicker magnet are as follows;
Charge up voltage
27.3 kV
4030 A
Maximum current
0.02 Tm
Magnetic field strength
Bending angle
7.6 0
Rise time< 200 nsec.
Flat top> 300 nsec.

"
"c..

~

E

8

+27.3kVFig. 1. Electric circuit diagram of the kicker system.

176

Fig. 2. Unit kicker magnet. View from the upstream sideof the beam line.

Figure 3 shows an integrated kicker magnetic fieldalong the muon beam path. The kicker field was measured in the air at a half of the maximum current.
The double pulsed muon beam structure which is calculated from the proton beam structure is also shownin the figure to clarify the relationship between themuon beam and the kicker field. At the tail of the firstmuon pulse the magnetic field starts to rise. After theestablishment of the flat top of the field the second
muon pulse comes into the kicker. The flat top of the
field is kept during the passage of the second pulse.
The rise time from 5% to 95% was less than 200 nsec
and the flat top was kept for about 300 nsec. Therefore, it is concluded that the kicker magnet has enoughcapability to separate the double pulsed muon beam.
Kicker Field vs Muon Pulse

o

200

400

600

800

1000

Time (nsec)

Fig. 3. Relationship between the calculated double pulsed
muon beam and the measured integrated kicker magnetic field.

symmetric distribution. Although the magnetic field
decreases slightly at the both ends of the axis, it isconfirmed by the beam trajectory calculation3 ) that
more than 90% muons can be transported in the homogeneous region.
The integrated kicker field was measured to be 35%
larger than the one estimated from the coil current andthe ferrite length, indicating the expansion of the effective field length. The 2-dimensional field calculation3 )indicated that there was a leakage field from the magnet edge along the beam line in the real case and thisleakage field increased the effective length of the kicker
magnetic field. Based upon the calculation the effective length of the kicker magnetic field should be about
1.38 times as large as the designed one and this expansion is the same with the one observed from the fieldmeasurement. This expansion will help to transport
higher momentum muons than originally expected. It
is concluded that this kicker magnet can be in use forthe muon beam with the momentum up to 65 MeV/c.
Figure 5 shows a result of the kicker magnet operation test at RAL using the real double pulsed surface
muon beam. As the trigger timing of the discharge
was changed from the early to the late, the first pulse
was kicked away and disappeared with no change ofthe pulse structure of the second pulse, and then thesecond pulse disappeared when the first pulse recovered. Therefore, it was confirmed that each single
muon pulse could be completely transported by the
kicker magnet.

Figure 4 shows the distribution of the integrated
kicker field along the axis from the coil to the mirror
plate including the beam center. Each data is shownby a percentage deviation from the measured value
at the beam center. The field distribution shows the140

Kicker Operation
2nd pulse

20

Kicker Field Homogeneity

OL...-............~--O-..cf....-----..,;.----'
· 100

-so

so

100

500

700

900

1100

1300

Kicker Tuning (os)Fig. 5. Separation of the surface muon beam (25.4 MeV Ic)
by operating the kicker magnet.

Horizontal Distance from Center (mm)Fig. 4. Distribution of the integrated kicker magnetic
field.

References
1) K. Nagmine et al.: Hyperfine Interact., 87, 1091 (1994).
2) E. G. Sandels: private communication.
3) K. Ishida: private communication.

177

RIKEN Accel. Prog. Rep. 28 (1995)

Concept ural Design of Accelerator Complex for
RIKEN RI Beam Factory
Y. Yano and A. Goto
The RARF proposes "RIKEN RI Beam Factoryj' asa next facility-expanding project. The factory takes
the aim at providing RI (Radioactive Isotope) beamsof the whole mass range with the world-highest intensities in a wide energy range up to several hundreds
MeV /nucleon. This short report describes a con<.;eptual design of an accelerator complex most suitable forrealizing the factory.
The best means to generate such RI beams is theutilization of the so-called "projectile fragmentation" .
In general, the reaction cross section for this projectile
fragmentation steeply enhances with increasing an energy of a primary beam up to 100 MeV/nucleon, and it
saturates above around this energy. Thus , in order toefficiently generate RI beams of the whole mass range
using this method, firstly, primary-beam energies are

required to exceed at least 100 MeV/nucleon even forvery heavy ions such as uranium. Due to this condition, the availability of RI beams at the RARF ispresently restricted to their mass less than around 60.
Yet it should be noted that much higher energies up
to 1 GeV /nucleon are not very advantageous becauseof the saturation effect in the cross sections mentioned
above. Secondly, needless to say, intensities of primarybeams must be as high as possible. Thirdly, from thecost-effectiveness point of view, the existing machines
should be exploited and utilized as much as possible.
Based upon these considerations, we propose an accelerator complex as illustrated in Fig. 1 which possesses
such acceleration performance that a 150 MeV/nucleon
uranium-beam with 0.5 p/-LA is obtainable.
A new injector composed of a frequency-tunable

18GHz
ECRIS
[constr.]

FCRFQ
f=18-38MHz

RILAC
f=18-38MHz

CSM
f=36-76MHz[constr.][existing][design]

RRC
f=18-38MHz
h=9[existing]SRC
f=18-38MHz
h=6[design]Fig. 1. Proposed accelerator complex for the RIKEN RI Beam Factory.

folded-coaxial RFQ linac (FCRFQ)l) equipped with an
18 GHz ECR ion source (ECRIS-18)2) is under construction in order to greatly upgrade the RILAC performance especially in the beam intensity. We use thismachine as the initial-stage of the accelerator complex.
A high-intensity heavy-ion d.c. beam produced by
the ECRIS-18 is bunched and accelerated by the
FCRFQ with transmission efficiency of about 90% evenat 1 rnA. The value of the efficiency was calculated by
the computer code PARMTEQ. This pre-accelerated
beam is fully accepted and accelerated by the existing
RILAC.
The output beam from the RILAC is passed througha charge-state multiplier (CSM, under design) to reduce its magnetic rigidity without velocity gain andinjected into the existing RRC. The CSM consists of anaccelerator, a charge stripper and a decelerator. The
accelerator and decelerator are of frequency-tunable

178

IH linacs, whose operational radio-frequencies are twotimes that of the RILAC to double an acceleration gradient. In the present design a maximum gap voltage
is set to be 340 k V, and total lengths of these linacs
are 8 meters (the partition into two or three units arenecessary) and 3.7 meters, respectively. Transmission
efficiency through the CSM depends only on charge
state distributions behind the charge stripper foil because the 6-dimensional emittance of the RILAC beamis already adiabatically dumped so as to be fully captured by the acceptance of the CSM linacs. We estimate the yield of a given charge state in terms of
Shima's formula 3 ) which is reliable in the relevant energy region. The CSM is a decisive device to obtain ahigher-intensity or higher-energy very-heavy-ion beamin the proposed accelerator scheme; with this device
the magnetic rigidity of a most-probable charge-state
beam can be decreased down to the acceptable value

of the RRC even when the injection velocity into the
RRC is increased.
Velocity of the RRC output beam is amplified bya factor of 2.4 with a six-sector superconducting ring
cyclotron (SRC, under design), when the mean extraction radius (5.70 m) of the SRC is taken to be 2.4 times
the mean injection radius (2.37 m). This mean injection radius is 2/3 times the mean extraction radius of
the RRC. To meet a good matching condition, the harmonic number in the SRC is taken to be 6 as that in
the RRC is 9. The preliminary calculation of betatronfrequency excursions implies that when we set the sector angle to be 20 degrees the maximum attainableenergy is limited to be around 500 MeV/nucleon to
avoid the crossing over l/z = 1.0 resonance.
Here, we illustrate acceleration of a uranium-ion
beam up to 150 MeV/nucleon. The rf frequency of the
RILAC is 25.5 MHz. A 238U19+ beam with an intensity(IECR) of 60 eJ-LA from the ECRIS-18 (this intensity
is extrapolated from the 10 GHz CAPRICE data) isaccelerated by the RILAC-CSM to 1.31 MeV/nucleon(ERILAC) . In the CSM the charge state is increased
from 19+ (qECR) to 49+ (qCSM). The yield of 49+
and the transmission efficiency of the FCRFQ are estimated to be 0.17 and 0.94, respectively, and thus abeam intensity of 0.5 pJ-LA is to be obtained. This beam
intensity (ISRC) is preserved up to the final energy, provided that the transmission efficiency of both of the
RRC and the SRC is 100% (this can be achieved by theoff-centering acceleration technique which is routinely
used for the RRC). The RRC output energy (ERRC) is21.7 MeV/nucleon, and the SRC final energy (ESCR)
is 150 MeV/nucleon. The SRC sector field (BSRC) isneeded to reach 5.48 T. Similarly, the maximum beam
intensities for typical gaseous elements are attainable
as listed in Table 1.
Table 1. Prospects of SRC beams.

RF frq qECR IECR ERILAC qCSM ERRC ESRC ISRC B SRCMHz
MeV lu MeV /u pttA tesla
ettA MeV/u
16
38.0
8 50.2 500 160 4.4
05 875 2.92
40Ar 35.0
16 42.1
43 4.77 880 2.48
370
84Kr 32.0 11 280 2.07
28 34.8 280
6 4.8
129
2 5.0
Xe 29.0 14 165 1.70
35 28.3 210
238
25.5 19
49 21.7 150
0.5 5.5
U
60 1.31

Quite high beam intensities can be provided especially for light ions, but use of such primary beams
is not realistic from a viewpoint of the radiationshielding-problem. We consider that a primary-beam
intensity of 1 pJ-LA is sufficient to generate RI beams in
the whole mass region with desirable intensities: These
primary beams will give us possibility to create andidentify as many as one thousand kinds of new isotopes.
References
1) O. Kamigaito et al.: This report, p. 168.
2) T. Nakagawa et al.: This report, p. 165.
3) K. Shima et al.: At. Data Nucl. Data Tables, 51, 174(1992).

179

RIKEN Accel. Prog. Rep. 28 (1995)

Double Storage Rings for Multi-Use Experimental Storage Rings
Proposed for RIKEN RI Beam Factory
T. Katayama, J. Xia, Y. Rao, Y. Yuan, and Y. Yano
A new type of experimental facility, MUSES (MultiUse Experimental Storage Rings) is proposed for
RIKEN RI beam factory. 1) It consists of Double Storage Rings (DSR) and a small-sized AccumulatorCooler Ring (ACR): The DSR is followed by the ACR.
This MUSES is installed downstream from an RI-beamgenerator for the Superconducting Ring Cyclotron(SRC). The DSR permits various types of unique colliding experiments: ion-ion merging or head-on collisions; collisions of electron and ion (stable or RI)
beams; internal target experiments; and atomic andmolecular physics with cooled electron beams. On theother hand, the ACR functions exclusively for the accumulation and cooling of RI beams as well as for theacceleration and radiation damping of electron beams:
i.e., RI or electron beams are improved in quality by
the ACR, and are injected into the DSR.
This report outlines the DSR. As for the ACR, refer
to Ref. 2.
Figure 1 shows a conceptual view of the DSR. The
two rings of the same specifications as shown in Table 1
are vertically stacked. Each lattice structure takes theform of a racetrack to accommodate two long straightsections. These straight sections of one ring verticallyintersect those of the other ring at two colliding points.
The ring circumference is 178.7 m, which is 5 times
the extraction circumference of the SRC. The maximum Bp-value becomes 12.76 Tm when a dipole fieldstrength is 1.5 T at the maximum. If high-energy ion
beams are demanded, the DSR serves as an ion synchrotron as well. The maximum energy is given, forexample, to be 3.0 GeV for protons; 1.2 GeV /nucleon
for light ions of q/ A = 0.5; and 0.82 GeV /nucleon for
U 92 + ions. For electrons the ACR boosts them up to
the maximum energy of 2.5 GeV, and these electrons
are stored in the DSR. In the present lattice structure,
the betatron tune values are 6.335 (horizontal) and(Slable or R I )Fig. 1. Conceptual view of the DSR.

180

Table 1. Parameters of the DSR.
Circumference C (m)Max. Bp (Tm)
Average radius R (m)Radius of curvature p (m)Max. beam energy (GeV / u)ProtonIon (q/A = 0.5)
(q/ A = 0.387)
Electron
Betatron tune values (Qx/Qy)
Momentum compaction
Transition 'Y
Max. betatron amplitude ({3x / (3y, m)Max. dispersion function (Dx/ D y , m)
Betatron amplitude at interaction
point ({3x * / (3y *, m)
Length of field-free section
at colliding section (m)178.694
12.76
28.44
8.506
3.00
1.20
0.82
2.50
6.350/5.763
0.04244.859
22.0/13.5
3.023/0.666
0.600/0.600
5.016

5.763 (vertical). The operating beam energy is kept
to be under the transition energy, since the transition
gamma is as high as 4.86. At the colliding points thebeta-function amplitudes are 0.6 m for both directions.
The field-free section near the colliding points whereexperimental detector systems are installed is 5.0 m inlength. These two long straight sections are dispersionfree.
.
One of the key researches planned in the DSR is thecolliding experiment of an electron beam with an RI
beam: in one ring of the DSR, 2.5 Ge V electrons areaccumulated and collided with an RI beam stored in
the other ring. This electron energy is determined so
as to obtain a sufficiently short de-Broglie wave-lengthof 0.2 fm in the rest frame of the RI beam. To keep a
sufficiently long Toushek lifetime, the RF voltage of 2.0
MV is applied to the electron beam. The detailed specifications of stored electron beams in the DSR are given
in Table 2. The number of stored electrons amounts
up to 1.9 X 10 12 particles. The typical colliding luminosity for the electrons and RI ions is estimated to be
5.6 x 1026 /cm 2 /sec., provided that 1 x 107 particles of
RI ions are stored. In order to further improve theluminosity, installation of a powerful pulsed heavy-ion
source e.g. a laser ion source, and use of the electron
cooling (the parameters are given in Ref. 2) in the DSR
should be considered.
Other experiments such as ion-ion merging collisions
at small angles are also envisaged. The luminosity is
expected to be around 1 x 10 26 /cm 2 /sec. when theTable 2. Parameters of the stored electron beam.
2.5
Max. stored beam energy Emax (GeV)
0.5
Max. stored beam current I (A)Max. stored No. of electrons N
1.86 x 10 12
2.5
Injection energy Ei (GeV)
Beam emittance at 2.5 GeV (cx/cy) (nm.rad)707.0/349.7
Energy spread ~E/E
7.09 x 10- 4
Bunch length (J' (cm)2.17
RF voltage VRF (MV)
2.0
Revolution frequency frev (MHz)1.677
RF frequency fRF (MHz)
503.3
300
Harmonic No. h
Toushek lifetime at 2.5 GeV (sec.)
4.06 x 10 5
Synchrotron radiation loss at 2.5 GeV (keV /turn)423

For internal target experiments in the DSR, thestochastic cooling method is used. The band width
is conservatively assumed at 500 MHz, and the feedback gain is 130 dB which is limited by an available
wide-band RF power of 100 kW. Some details are given
in Table 3.
Table 3. Parameters of the stochastic cooler.
Cooling time (sec.)
Longitudinal
Transverse
Band width W (MHz)Ambient temperature T (K)
Total microwave power P (kW)

1
15
500

18
100

References
number of stored ions are assumed at the space charge
limit of 4 x 1012 particles.

1) Y. Yano et al.: This report, p. 178.
2) T. Katayama et al.: This report, p. 182.

181

RIKEN Accel. Prog. Rep. 28 (1995)

Accumulator-Cooler Ring for Multi-Use Experimental Storage
Rings Proposed for RIKEN RI Beam Factory
T. Katayama, J. Xia, Y. Rao, Y. Yuan, and Y. Yano
Supposing that RI beams possessing relatively low
quality of emittances are accumulated in the DSR 1) up
to the space-charge limit, the acceptance of the DSR
is required to be intolerably large. Thus, we are investigating the net cost-effectiveness for introducing an
extra small-sized Accumulator-Cooler Ring (ACR) before the DSR. This ACR functions exclusively for theaccumulation and cooling of RI beams as well as for theacceleration and radiation damping of electron beams:
i.e., RI or electron beams are improved in quality by
the ACR, and are injected into the DSR. With the
ACR, the acceptance required for the DSR is significantly reduced.
Taking the accumulation and cooling of an extremely neutron-rich 132Sn50+ (a double-magic nucleusof 40 sec. in half-life) beam of 210 MeV/nucleon for an
example, we give some specifications of the ACR. This
RI beam is produced via the projectile fragmentationof a primary beam of 136Xe ions with a peak currentof 2 pJlA (see Ref. 2). Typical beam characteristics
are estimated: The production rate is nearly 1 x 107
particles per sec.; the momentum spread is ±0.1 %; thephase width relative to RF frequency is ±10 degrees;
and the transverse emittances are 4.5 7r mm.mrad inboth horizontal and vertical directions.
The above RI beam is stored in the ACR, firstly
with the conventional multi-turn injection method.
About 1 x 10 particles are injected for each one turnrevolution, because the orbit frequency is nearly 1
MHz. Provided that the acceptance of horizontal
phase space of the DSR is designed to be 125 7r
mm.mrad, and that the dilution factor is 1.25, after
22-turn injection the emittance of the stored beam becomes as large as the full acceptance. At this moment, the number of the stored particles increases
up to 2 X 10 2 particles. Secondly, the stored particles are RF -stacked: The RF voltage of 24 k V
is applied, and the frequency is swept from 29.12
MHz (corresponding to 210 MeV /u) to 29.44 MHz.
This frequency sweep brings about changes in the
beam momentum and average radius by 1.8% and
17 mm, respectively. This multi-turn-injection plus
RF-stacking process is repeated at 10 Hz. During
this process the RF -stacked beam continually undergoes the electron cooling at the top energy. Typical

182

parameters of the electron cooler is tabulated in Table
1. The longitudinal and transversal cooling times are
estimated to be as short as 0.1 sec. and 10 sec., respectively. After a sufficiently longer period than the
intrinsic half-life, the number of the coasting particles
accumulated in the ACR amounts up to the equilibrium value of 1 x 105. The momentum spread andemittances become less than 0.15% and nearly 1 7r
mm.mrad, respectively. This high-quality stored beam
is fast extracted, and is injected into the DSR by one
turn.
Table 1. Paramters of the electron cooler.
Maximum electron energy (keV)
Maximum cooled ion energy (MeV lu)
Maximum electron current (A)Cathod diameter (mm)Electron diameter at cooling section (mm)Length of cooling section (m)Cooling time (sec.) for 210 MeV lu 132Sn+50
Longitudinal (~p/p = 0.1%)
Transverse (c = 125 7r mm.mrad)

300
500
10

5.81
50
3.0
0.1
10

The ACR serves also as an electron synchrotron toaccumulate electrons from a 0.5 GeV linac and to boost
them up to 2.5 GeV. At the initial energy of 0.5 GeV,
the radiation damping is induced: The damping times
are estimated to be 0.5 sec.' for the transverse direction,and 0.26 sec. for the longitudinal direction, which areshort enough for accumulating electrons. The acceleration up to 2.5 Ge V is done within 1 sec., and the equilibrium transverse emittances become as small as 0.43
nm.rad for the horizontal direction and 0.11 nm.rad forthe vertical direction. The number of stored electrons
is estimated to amount up to about 2 x 10 12 particles.
This top-energy electron beam is fast extracted andinjected into the DSR by one turn.
The optimization of parameters of the ACR is underway.
References
1) T. Katayama et al.: This report, p. 180.
2) Y. Yano et al.: This report, p. 178.

VI.

RADIATION MONITORINGRIKEN Accel. Prog. Rep. 28 (1995)

Leakage Radiation Measurements in the Ring Cyclotron Facility
S. Fujita, N. Nakanishi , S. Nakajima, M. Watanabe,* H. Ohishi,* K. Tanaka,*
Y. Uwamino, and T. T. Inamura
The measurements of leakage radiation were carriedout with three kinds of beams: 135 MeV /u deuteronand 28Si beams, and 113 MeV proton beam. The
beam intensities were 200 pnA for proton, 10 pnA for
deuteron, and 4 pnA for 28Si. The beams were stopped(a)r

at an iron target in the beam distribution corridor.
Leakage radiation of neutrons from the corridor wasmeasured with four neutron dose rate meters, TPS451S's (Aloka). The beam current at the target wasread with a current integrator (ORTEC 439) andrecorded with a personal computer. Figures 1-(a) , (b),and (c) show the target point and positions where leakage radiation was measured in this experiment. The
positions, IFc and B2c, are on the first floor and 2nd
basement floor just right upper and under the target
point, respectively. Leakage of neutrons was detected
at the several points outside of the building. Results
are summarized in Table 1. Dose rates were normalized with respect to the beam intensity of 1 pJ-LA.
Table 1. Dose rates of neutron leakage radiation froma target point in the beam distribution corridor. [seeFigs. 1-(a), (b), and (c)].
Measureddate
Accelerated
Particle

ruR

(b)

...

Beam Distribution corridor
X

rucx

OUtL x.\..

Test target point

I

Energymeasured
position
1F a

IF c------- - 1F b--- - -----

ES a
ES c
---- ---- ES b---- - - -- E4 a
E4 c------ -- E4 b

May. 19 - 20, 1994

Oct. 1 - 2, 1994

dOct. 16 - 17. 1994

p

135 MeV/u
135 MeV/u
113 MeVdose rate
dose rate
dose rate(~Sv/h)/(p ~ A) (~Sv/h)/(p ~ A) (~Sv/h)/(p ~ A)
1.11E+OO

2. 1SE-02
1.22E-02-------- - -- 1.04E+01------------ ------ - -- -- - -------------------------?~~~~~~~-2.66E+02
2.81 E+02------------ - - -------- - - -----------__ ! .~~.!=_+_O_2_____ ]~~~~~~~ _____ l.:~!~:!"Q~ __3.40E+02
2.45E+02
4 .84E+01==~~!~!P]~~~==]~~~~~q~~====~§~~~QQ==
3 .99E+01
S.93E+01
2.75E+OO------------ ----- - -- ----Out R--Out-C--------Out L--------W R

weW L

5.45E+Ol

2.70E-01
2.26E-01(c)Fig. 1. Partial layout of the RIKEN Ring Cyclotron
facility where the leakage radiation measurement was
made. (a) Part of the 2nd basement floor; (b) Partof the 1st basement floor; (c) Part of the 1st floor.
The target point is denoted by a closed circle. Leakage-radiation-dose measuring points are denoted by x .
Faculty of Science and Technology, Chuo University

On the other hands, the automatic monitoring ofleakage radiation using a computer (MX-3000) was alsodone continuously during this year. From the accumulated data for leakage neutrons, the radiation levels
have been found to be less than the safety limit in thecontrolled area (1 mSv /week) and at the boundary of
the controlled area (0.3 mSv /week) through the wholeyear. Leakage of neutrons has been recorded with oneof the environmental monitors in the above deuteronexperimental period. This radiation level, however, is
far less than the safety limit (1 mSv/year) required at
the boundary of the facility.
183

RIKEN Accel. Prog. Rep. 28 (1995)

Residual Activities in the Ring Cyclotron Facility
S. Fujita, M. Watanabe,* H. Ohishi,* K. Tanaka,* N. Nakanishi, Y. Uwamino, and T. T. Inamura
Residual activities were measured at various points
in the Ring Cyclotron facility. The measurements were
performed during the routine overhaul period and afteralmost every beam time. In the following we describe
significant activities observed in the measurements.
Just after the last experiment of the spring term,
which was carried out with an 18 0 8 + beam of 100
MeV lu in the E6 experimental vault from August 2 to8, the routine overhaul started. The dose rates causedby the residual activities in the Ring Cyclotron and theinjector AVF cyclotron were measured on Aug. 23 and30, during the overhaul period. The results are shownin Figs. 1 and 2 along with the detection points.

]= Main
Probe

DOSE UNIT: pSv/h

Beam

Fig. 2. Dose rates measured inside the injector AVF cyclotron. They are given in units of J.LSV /h.
Table 1. Summary of the residual activities measured
along the beam lines with ionization-chamber survey
meters. The points a-y indicate the detection points
shown in Fig. 3.
Detection
point

Fig. 1. Detection points around the RIKEN Ring
Cyclotron: EDC, the electrostatic deflection channel;
MDC1, the magnetic deflection channell; MDC2, themagnetic deflection channel 2; MDP1, the main differential probe 1; MDP2, the main differential probe 2;
MDP3, the main differential probe 3. Indicated numerals are dose rates in units of J.LSV /h.

a
b
c
d
e
f
g
h
j
k
I
m
n
0

In the period from Oct. 1, 1993 to Sep. 30, 1994,
residual activites were measured along the beam lines
with portable ionization chambers. The points a-y
in Fig. 3 denote the places where the dose rates exceed 50 J-tSv Ih. Table 1 summarizes the observed dose
rates along with the dates on which the measurements
were performed. The maximum dose rate was foundto be 50000 J-tSv Ih at the production target chamberof RIPS, denoted by point I in Fig. 3.
Faculty of Science and Technology, Chuo University

184

p
q

r
s
t
u
v
w
x

y

Measured
dose rate(J.LSv/h)
400
300 ·
100
1500
110
800
350
220
60
1400
230
50000
120
50
120
120
56
110
50
120
800
400
120
150
80

Date

Aug.
Aug.
Aug.
Feb.
Nov.
Nov.
Apr.
Apr.
July
July
July
Apr.
Apr.
Dec.
Dec.
May
Aug.
Oct.
Oct.
July
Dec.
May
May
May
May

15, 1994
15, 1994
15, 1994
8, 199429, 1993
29, 1993
4, 1994
4, 1994
20, 1994
20, 1994
20, 1994
4, 1994
4, 1994
7, 19937, 19932, 1994
16, 1994
12, 1993
28, 1993
28, 1994
7, 199318, 1994
18, 1994
18, 1994
18, 1994

Fig. 3. Layout of the RIKEN Ring Cycrotron facility as of 1994. Monitoring positions are denotedby x. Detection points of residual activities along the beam lines are denoted by a-yo

At almost all the detection points, larger values of
the residual activities were observed compared to thoseof the previous report. 1 ) This is due to the increase of
the beam intensities since last year.

References
1) S. Fujita, K. Tanaka, M. Watanabe, N. Nakanishi, andT. Inamura: RIKEN Accel. Prog. Rep., 27, 169 (1993).

185

RIKEN Accel. Prog. Rep. 28 (1995)

A Film Badge Reading System for the Radiation Safety Control
S. Fujita and N. Nakanishi
The radiation safety control system of the Ring Cyclotron Facility has worked steadily since 1986, performing radiation protection control continuously andautomatically. 1)
Since the facility was completed, a card-operated
gate-bar system has been employed in the controlled
area. In this system, when one enters into and leaves
from the controlled area, all he has to do at the gate
is to insert his own ID card into a card reader. A hostcomputer (MX-3000) confirms that he is a good registrant and then opens the gate, recording the entering
time together with his name in its memory. According to the radiation protection rules of the facility, heis required to have his own film badge (denoted by
FB, hereafter) with him inside the area and to record
a place and purpose of his work there when he enters. These rules had not been followed very much byusers, since the system could not check them. Thus,
we started to improve this situation.
In 1988, a personal computer PC9801 was installedat the entrance gate of the controlled area in order to
input the place and purpose easily. But the place andpurpose could not be recorded correctly, because thecomputer had not been connected with the existingradiation safty control system.
In 1993, the card readers were replaced with FBreaders. The procedure to keep records for enteringand leaving the controlled area was much improvedby introducing the FB-reading system. In the new
system, no one can enter the controlled area without
bringing his FB and inputting his own record. First,
one has to show his FB to a FB reader at the entrance
gate bar. Then the selection menue only for him starts
automatically on a display of the PC9801. He caneasily input the place where he is going and the purposeof his work there with a touch panel on the display.
The computer stores these data and transfer them tothe host computer (MX-3000). Finally the MX-3000
confirms the person and opens the gate bar.
Figures 1 and 2 show the photograph and the block
diagram of the FB-reading system.
The system has a lot of new functions as follows:(1) Display of names of all persons in the controlled
area,(2) Display of the message for the available intervalof the film badge,(3) An unallowed person is restricted to enter thecontrolled area and the display shows the message forthe reason,(4) Automatical register of in-out data for the controlled area,

186

Fig. 1. The photograph of the film badge reading system.

MPX(RS-232c)(RS-232c)

PC9801(touch ponel)

entrancegate-bar

HFC')--_----'lmonilor

Fig. 2. The schematic block diagram of the film badge
reading system.

(5) Automatical recovery from the system error between the card-operated gate-bar and the personal
computer, and so on.
Now we are planning to install new film badge readers for all gate-bars in the Ring Cyclotron Facility.
References
1) 1. Sakamoto, S. Fujita, T. Wada, and H. Takebe:
RIKEN Accel. Prog. Rep., 20, 206 (1986).

RIKEN Accel. Prog. Rep. 28 (1995)

Measurement of Activities Induced by 135 MeV lu 28Si Incident on
an Iron Target with the Activation Method
N. Nakanishi, S. Nakajima, S. Fujita, T. Minemura,* and M. Watanabe*
A series of measurements have been carried out for
135 MeV lu various incident particles on a thick irontarget with the activation method in order to get information on the incident particle dependence of a neutron yield.
Here, the activity induced in metals by neutrons produced by 135 MeV lu 28Si beams incident on a thickiron target is briefly presented. Seven metals of C, AI,
Fe, Co, Ni, In, and Au are used as neutron detectors
and 11 reactions are adopted as the probe of activation intensity. These metal detectors were placed atscattering angles of 0, 30, 60, 90, 120, and 140 degs.
Si +Fe10 . 25 ~--+---+----t--+---t----l(j)

C(n.2n)~~AI(n,a)W-

26

Fe(n ,p)~N

Co(n,2n)~ 10 ' 2 7l-----+--""*'~~"=:---"""":___r_-·t:Co(n,a )Ni(n ,p)Ni(n,2n).!3..
?:' 10 . 28 - - - -In(n,n')Au(n,4n ):~Au( n,2n)«u 10 . 29 ._ _.

Au( n,g)'Angle(deg)Fig. 1. Angular distributions of activities of 11 isotopes
produced by 135 MeV lu 28Si incident on a thick irontarget.

Gamma rays were measured after irradiation. Detailsof the experiment are described elsewhere. 1) Figure 1
shows the angular dependence of induced activities inthe detectors through various nuclear reactions. The
activity is basically represented as the product of aneutron activation cross section and the neutron number produced by an incident particle. In this kind ofexperiment, only the activity is obtained. Thus, wemust have information on activation cross sections of
employed detectors in order to get the information of
the neutron yield and vice versa. The reactions andcharacteristics of detectors are also given in Ref. 1.
Unfortunately, activation cross sections are known
at most up to several tens MeV only in a neutronenergy, while even energetic neutrons whose energies
are much higher than energies per nucleon of incident
beams are emitted from a target in the case of incidence of composite particles. To get activation crosssections at high neutron energies, we are now going on
experiments using protons with specific high energies
at which neutron flux data exist.
Hereafter, the activity will be unfolded using newly
obtained activation cross sections, and the neutron flux
will be evaluated and a further mechanism producing
neutrons in the target will be examined based on theintra-nuclear cascade evaporation model.
References
1) N. Nakanishi et al.: Proc. 9th Symp. on Accel. Sci. andTech. , Tsukuba, p. 425 (1993).

Faculty of Science and Technology, Chuo University

187

RIKEN Accel. Prog. Rep. 28 (1995)

Neutron Dose Equivalent near a Thick Iron Target
Induced by 135 MeV In Ions
S. Nakajima, N. Nakanishi, and S. Fujita
We once measured an angular distribution of theneutron dose equivalent around a thick iron target using a commercially available rem counter when the target was being bombarded by a 135 MeV/nucleon 14N
beam. Since then, we have observed the dose equivalent near the target at a right angle to the beam
direction every time when an experiment using theactivated-foil method was done. A part of these results is shown in Fig. 1. The figure shows that there issome incident particle dependence in the dose equivalent.
According to a text,1) a dose equivalent of neutrons
produced by protons of energy below 1 GeV on a thickiron target is roughly described by equations:--e--- calc. p(135)
<C

::::L

109

•

..e.r:.

X

•

">

en

::::L

ar
u
c

ftI

u;

108

where E is an incident proton energy in GeV and 0 anangle in degree.
The angular distribution calculated by the equationis also plotted in Fig. 1. The magnitude is a few times
larger in the case of 14 N than the calculation for protons, but the shape of them resembles each other. This
indicates that the dose equivalent induced by heavy
ions can also be described by a similar equation with aslight modification including the incident particle dependence. When such an equation is found, a total
neutron flux will be able to be obtained by a simple measurement of the dose equivalent using a rem

188

C(135)
Ne(135)

:c
iii

'E
u

107

'iii

>
-:;

•

a-

u

::
0

106
0

45

90

135

180

Angle(deg)at 1 m distance, andq = 3.6E1. 6 ,P(H2-135)d(135)!

0¢(O) = 864 x 5000(1 - e-q)/(O + 40/VE)2Sv /h/pf-LA~N-14(135)Fig. 1. Neutron dose equivalent measured with a commercially available rem counter and that calculated for
protons.

counter.
But a commercially available rem counter clearlycatches only a small fraction of produced neutrons,
then an ingenious invention is necessary to obtain an
accurate dose equivalent.
References
1) A. H. Sullivan: A guide to radiation and radioactivity
levels near high energy particle accelerators, Nuclear
Technology Publishing, Ashford, Kent, GBR (1992).

VII. LIST OF PUBLICATIONS
1.

Accelerator
physics

development

andaccelerator

Y. K. Batygin: "A Structured-Modular Approach toSoftware Design for High Current Beam Dynamics
Simulation", AlP Conf. Proc. 297, Los Alamos, p.
196 (1994).
Y. K. Batygin: "Particle Distribution Generator in 4D
Phase Space", ibid., p. 419.
M. Niimura and R. J. Churchill: "Current Scaling ofProjectile Velocities with and without a Snowplow
Effect in Electromagnetic Launchers", IEEE Trans .
Magnetics, 29, 1249 (1994).
S. Wakasa, K. Fukuda, T. Takagi, and N. Nakanishi:"Design of an Ultra Compact Cyclotron for Particle Induced X-Ray Emission", Int. J. PIXE, 3 , 329(1993).
O. Kamigaito, A. Goto, Y. Miyazawa, T. Chiba,
M. Hemmi, M. Kase, and Y. Yano: "Design of a
New Type of Variable-Frequency Radio-Frequency
Quadrupole Linac with a Folded-Coaxial Resonator", Jpn. J. Appl. Phys. , 33, L537 (1994).
M. Niimura and H. Amemiya: "Effect of Charged Dust
in a High-energy Electron Beam", Proc. Int. Symp.
on Dust and Dirty Plasma, Noise, and Chaos inSpace and in the Laboratory, Plenum Press, New
York, p. 33 (1994).
O. Kamigaito, A. Goto, Y. Miyazawa, T. Chiba, M.
Hemmi, S. Kohara, M. Kase, and Y. Yano: "Designof a New Type of Variable-Frequency RFQ Linac
with a Folded-Coaxial Resonator" , Proc. 19th Linear
Accelerator Meeting in Japan, Tokai, p. 84 (1994).
O. Kamigaito: "Design of a Variable Frequency RFQ
Linac for RILAC", RIKEN Rev., No.4, p. 65 (1994).
2.

Nuclear physics and nuclear instrumentation

K. Sumiyoshi and H. Toki: "Relativistic Equation ofState of Nuclear Matter for the Supernova Explosion
and the Birth of Neutron Stars", Astrophys. J., 422,
700 (1994).
O. V. Bochkarev, A. A. Korsheninnikov, E. A. Kuzmin,
I. G. Mukha, L. V. Chulkov, and G. B. Yankov:"NN-Interaction in the Final State of Three-Particle
Decays of Nuclei 6He(2+) , 6Li(2+, T = 1), and6Be(2+)", Bull. Rus. Acad. Sci. Phys. , 57, 932(1993).
I. Tanihata: "Application of Radioactive Nuclear
Beams" , Butsuri, 49, 433 (1994).
K. Matsuta, A. Ozawa, Y. Nijiri, 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: "BetaNMR Detection of Beta-Emitting Fragment 43Ti" ,Hyperfine Interact. , 78, 123 (1993).
K. Matsuta, A. Ozawa, Y. Nijiri, 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: "Fragment Polarization of 43Ti in the 43T + C Collision",
ibid., p. 127.
K. Matsuta, A. Ozawa, Y. Nijiri, 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: "Production of Unstable Nuclei Far from the Stability Line:
Its Scope on Limitations", ibid., p. 1219.
K. Ishida, S. Sakamoto, Y. Watanabe, T. Matsuzaki,
and K. Nagamine: "X-ray Studies of Muon Transfer
Reactions from Hydrogen to Helium", ibid., 82, 111(1993).
H. Veno, H. Okuno, K. Asahi, H. Sato, T. Kubo, T.
Nakamura, N. Inabe, A. Yoshida, Y. Ohkubo, M.
Adachi, T. Ichihara, M. Ishihara, T. Shimoda, H.
Miyatake, N. Takahashi, and W.-D. Schmidt-Ott:"Spin-polarized Radioactive Beams and ,8-NMR Experiments", ibid., 84, 371 (1994).
K. Nagamine, T. Matsuzaki, K. Ishida, I. Watanabe, and R. Kadono: "Construction of RIKEN-RAL
Muon Facility at ISIS and Advanced j.LSR", ibid., 87,
1091 (1994).
I. Tanihata:"Physics Wit Radioactive Nuclear
Beams", New Frontiers in Nuclear Physics (Lecture Notes of JSPS-INS International Spring School),edited by S. Homma, Y. Akaishi, and M. Wad a ,World Scientific, p. 241 (1993).
A. S. Dem'yanova, H. G. Bohlen, B. Gebauer, S. A.
Goncharov, A. A. Korsheninnikov, Ch. Langner, M.
von Lucke-Petsch, W. von Oertzen, A. A. Ogloblin,
O. Ya. Osadchy, A. N. Ostrovski, M. Wilpert, andTh. Wilpert: "Rainbow Scattering of Radioactive
Nuclei and the Isospin Dependence of the N ucleusNucleus Potential", Nucl. Phys., A553, 727c (1993).
A. A. Korsheninnikov, B. V. Danilin, and M. V.
Zhukov: "Possible Existence of lOHe as Narrow
Three-body Resonance", ibid., A559, 208 (1993).
A. A. Korsheninnikov and T. Kobayashi: "Main Mechanisms in Fragmentation of the Exotic Nucleus 6He" ,ibid., A567, 97 (1993).
J. Kasagi and K. Yoshida: "Giant Dipole Resonancesin Very Hot Nuclei", ibid., A569, 195c (1994).
T. Ichihara, T. Niizeki, H. Okamura, H. Ohnuma, H.
Sakai, Y. Fuchi, K. Hat an aka, 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 EjA = 135
MeV" , ibid., p. 287c.
K. Sugawara-Tanabe, A. Arima, and N. Yoshida: "TheSpin-orbit Interaction and SU(3) Generators in Su189

perdeformation", ibid., A570, 291c (1994).
K. Varga, Y. Suzuki, and R. G. Lovas: "Microscopic
Multicluster Description of Neutron-halo Nuclei witha Stochastic Variational Method", ibid., A571, 447(1994).
T. Niizeki, H. Ohnuma, T. Yamamoto, K. Katoh, T.
Yamashita, Y. Hara, H. Hanaki, H. Okamura, H.
Sakai, S. Ishida, N. Sakamoto, H. Ohtsu, T. Wakasa,
T. Uesaka, Y. Satou, T. Fujita, T. Ichihara, H.
Orihara, H. Toyokawa, S. Kato, S. Kubono, and M.
Yosoi: "Spin-Isospin Strength Distribution in SdShell Nuclei Studied by (d,2He) Reactions at Ed =270 MeV", ibid., A577, 37c (1994).
H. Okamura, S. Ishida, N. Sakamoto, H. Otsu, T.
Uesaka, T. Wakasa, Y. Satou, S. Fujita, H. Sakai,
T. Niizeki, K. Katoh, T. Yamashita, Y. Hara, H.
Ohnuma, T. Ichihara, and K. Hatanaka: "Study of
the Spin-Dipole State via the (d,2He) Reaction at
270 MeV", ibid., p. 89c.
T. Ichihara, M. Ishihara, H. Ohnuma, T. Niizeki,
Y. Tajima, T. Yamamoto, K. Kato, S. Katoh, T.
Yamashita, Y. Fuchi, S. Kubono, M. H. Tanaka, H.
Okamura, S. Ishida, T. Uesaka, Y. Satou, and T.
Fujita: "e 2C, 12 N) Reaction at EIA = 135 MeV as
a Probe of Spin-Isospin Excitation", ibid., p. 93c.
H. Toki, H. Suganuma, and S. Sasaki: "Magnetic
Monopole Condensation for Confinement and Chiral Symmetry Breaking," ibid., p. 353c.
1. Tanihata: "Neutron Skin and Neutron Halo", Parity, 9, 42 (1994).
O. V. Bochkarev, A. A. Korsheninnikov, E. A. Kuzmin,
1. G. Mukha, L. V. Chulkov, and G. B. Yankov:"Spectrum of Neutrons from the Three-Particle Decay of 6He(2+) and Its Structure", Physics of Atomic
Nuclei (former Sov. J. Nucl. Phys.) , 57, 1281 (1994).
M. Louvel, A. Genoux-Lubain, G. Bizard, R. Bougault ,R. Brou, A. Buta, H. Doubre, D. Durand, Y. El
Masri, H. Fujiwara, K. Hagel, T. Hamadai, F.
Hanappe, S. C. Jeong, G. M. Jin, S. Kato, J. L.
Laville, C. Le Brun, J. F. Lecolley, S. M. Lee, T.
Matsuse, T. Motobayashi, A. Peghaire, J. Peter, R.
Regimbart, F. Saing-Laurent, J. C. Steckmeyer, and
B. Tamain: "Rapid Decrease of Fragment Emission
Time in the Range of 3- 5 MeV lu Excitation Energy", Phys. Lett., B320, 221 (1994).
M. Tohyama: "Giant Resonances in a Neutron Rich
Nucleus", ibid., B323, 257 (1994).
T. Ichihara, M. Ishihara, H. Ohnuma, T. Niizeki, Y.
Yamashita, T. Yamamoto, Y. Fuchi, S. Kubono, M.
H. Tanaka, H. Okamura, S. Ishida, S. Miyamoto,and H. Toyokawa: "Charge Exchange Reaction
12Ce2C,12N)12B at EIA = 135 MeV", ibid., p. 278.
T. Horibata and N. Onishi: "Tilted Axis Rotating
States in 1820s Yrast", ibid., B325, 283 (1994).
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.
190

Shimoura, T. Suzuki, 1. Tanihata, Y. Watanabe, andM. Yanokura: "Observation of 10He", ibid., B326,
31 (1994).
T. Nakamura, S. Shimoura, T. Kobayashi, T.
Teranishi, K. Abe, N. Aoi, Y. Doki, M. Fujimaki,
N. Inabe, N. Iwasa, K. Katori, T. Kubo, H. Okuno,
T. Suzuki, 1. Tanihata, Y. Watanabe, A. Yoshida,
and M. Ishihara: "Coulomb Dissociation of a Halo
Nucleus 11 Be at 72A MeV", ibid., B331, 296.
A. Ozawa, T. Kobayashi, H. Sato, D. Hirata, 1.
Tanihata, O. Yamakawa, K. Ornata, K. Sugimoto,D. Olson, W. Christie, and H. Wieman: "Interaction Cross Sections and Radii of Mass Number
A = 17 Isobars (17N, 17F, and 17Ne)", ibid., B334,
18 (1994).
H. Okuno, K. Asahi, H. Sato, H. Ueno, J. Kura,
M. Adachi, T. Nakamura, T. Kubo, N. Inabe, A.
Yoshida, T. Ichihara, Y. Kobayashi, Y. Ohkubo, M.
Iwamoto, F. Ambe, T. Shimoda, H. Miyatake, N.
Takahashi, J. Nakamura, D. Beamel, D. J. Beaumel,
W.-D. Schmidt-Ott, and M. Ishihara: "Systematic
Behavior of Ejectile Spin Polarization in the Projectile Fragmentation Reaction", ibid., B335, 29(1994).
M. Wakasugi, W. G. Jin, T. T. Inamura, T. Murayama,
T. Wakui , H. Katsuragawa, T. Ariga, T. Ishizuka,
and 1. Sugai: "Precision Measurement of the Hyperfine Structure and Nuclear Moments of 180mTa by
Laser-rf Double-resonance", Phys. Rev. A, 50, 4639
(1994).
S. Hirenzaki, T. Suzuki, and 1. Tanihata: "General
Formula for the Coalescence Model", Phys. Rev. C,
48, 2403 (1993).
A. Elmaani, J. M. Alexander, N. N. Ajitanand, R.
A. Racey, S. Kox, E. Latard, F. Merchez, T.
Motobayashi, B. Noren, C. Perrin, D. Rebreyend,
T. U. Chan, G. Auger, and S. Groult: "Breakup ofIntermediate-mass Fragments, 8Be and 6Li, Formedin the Reaction 40 Ar + Ag at 7.8A and 17 A MeV",
ibid., p. 2864.
A. Elmaani, J. M. Alexander, N. N. Ajitanand, R.
A. Lacey, S. Fox, E. Liatard, F. Merchez, T.
Motobayashi, B. Noren, C. Perrin, D. Rebreyend, T.
U. Chan, G. Auger, and S. Groult: "Lifetime of Well
Characterized Hot Nuclei via Small-Angle ParticleParticle Correlations: 40 Ar + Ag (E I A = 7.8 and 17
MeV)", ibid., 49, 284 (1994).
O. Hashimoto, H. Hamagaki, T. Kobayashi, Y.
Shida, 1. Tanihata, O. Yamakawa, N. Yoshikawa,
S. Nagamiya, J. A. Bistirlich, K. M. Crowe, T. J.
Humanic , M. Justice, J. O. Rasmussen, and Y.-W.
Xu: "Projectile Rapidity Pions in 775 MeV I Nucleon
139La + 12C and 139La + 139La Reactions" , ibid., p.
420.
T. Otsuka, M. Ishihara, N. Fukunishi, T. Nakamura,and M. Yokoyama: "Neutron Halo Effect on Direct
Neutron Capture and Photodisintegration", ibid., p.
R2289.

M. V. Zhukov, A. A. Korsheninnikov, and M. H.
Smedberg: "Simplified Q + 4n Model for the 8He
Nucleus", ibid., 50, R1 (1994).
K. Varga, Y. Suzuki, and Y. Ohbayashi: "Microscopic
Multicluster Description of the Neutron-rich Helium
Isotopes", ibid., p. 189.
T. Suzuki and T. Otsuka: "Configuration of the TwoNeutron Halo of 11 Li and Gamow-Teller Transition" ,ibid., p. R555.
K. H. Kim, T. Otsuka, and M. Tohyama: "Transfer
and Fusion Reactions of Unstable Nuclei", ibid., p.
R566.
K. Varga and R. J. Liotta: "Shell Model on a Random
Gaussian Basis", ibid., p. R1292.
T. Motobayashi, N. Iwasa, Y. Ando, M. Kurokawa, H.
Murakami, J. Ruan (Gen) , S. Shimoura, S. Shirato,
N. Inabe, M. Ishihara, T. Kubo, Y. Watanabe, M.
Gai, R. H. France III, K. I. Hahn, Z. Zhao, T.
Nakamura, T. Teranishi, Y. Futami, K. Furutaka,and Th. Delbar: "The Coulomb Dissociation of
8B and the 7Be(p,,),)8 B Reaction at Low Energies",
Phys. Rev. Lett. , 73 , 2680 (1994).
D. Hirata, H. Toki , I. Tanihata, K. Sumiyoshi, Y.
Sugahara, and R. Brockmann: "Relativistic Mean
Field Theory for Unstable Nuclei", Proc. 3rd Int.
Conf. on Radioactive Nuclear Beams, edited by D.
J. Morrissey, p. 247 (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., p. 357.
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: "Production and Polarization of Beta-Emitting Projectile
Frag~ent 43Ti", ibid., p. 377.
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", ibid., p. 383.
A. Ozawa, T. Kobayashi, H. Sato, I. 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 (17N, 17N, and 17Ne)", ibid., p.
395.
I. Tanihata: "Study of Light Exotic Nuclei Using
Radioactive Nuclear Beams", Proc. of Int. SchoolSeminar on Heavy Ion Physics, edited by Yu.
Ts. Oganessian, Yu. E. Penionzhkevich, and R.
Kalpakchieva, 1, 3 (1994).
W. Benenson, D. Bazin, J. H. Kelley, D. J. Morrissey,
N. A. Orr, R. Ronningen, B. B. Sherrill, M. Steiner,

M. Thoennessen, J. A. Winger, S. J. Yennello, B. M.
Young, I. Tanihata, X. X. Bai, N. Inabe, T. Kubo,
C.-B. Moon, S. Shimoura, T. Suzuki, R. N. Boyd, K.
Subotic: "Isomer Production in Fragmentation Reactions", Proc. 10th Winter Workshop on Nuclear
Dynamics, "Advance in Nuclear Dynamics", Snowbird, Utah, USA, Jan. 16-22, 1994, edited by J. Harris, A. Mignerey, and W. Bauer, World Scientific, p.
175 (1994).
S. Yamaji, A. S. Jensen, and H. Hofmann: "Isoscalar
Vibrational States in Hot Nuclei", Progr. Theor.
Phys., 92, 777 (1994).
M. Tohyama: "Stationary Solution of a Time Dependent Density Matrix Formalism", ibid., p. L905.
H. G. Bohlen, B. Gebauer, M. von Lucke-Petsch,
W. von Oertzen, A. N. Ostrovski, M. Wilpert,
Th. Wilpert, H. Lenske, D. V. Alexandrov, A. S.
Demyanova, E. Nikolskii, A. A. Korsheninnikov, A.
A. Ogloblin, R. Kalpakchieva, Y. E. Penionzhkevich,and S. Piskor: "Solution of the loLi-Puzzle", Z.
Phys. , A344, 381 (1993).
K. Varga, R. G. Lovas, and R. J. Liotta: "Absolute
Alpha-Decay Width of 212pO in a Mixed Shell-andCluster Model", ibid., A349, 345 (1994).
K. Varga, R. G. Lovas, and Y. Suzuki: "Microscopic
Multicluster Description of Neutron Halos", ibid., p.
347.
A. Odahara, Y. Gono, S. Mitarai, E. Ideguchi, M.
Kidera, M. Shibata, T. Morikawa, T. Kishida, K.
Morita, A. Yoshida, H. Kumagai, Y.-H. Zhang, A.
Ferragut, T. Murakami, M. Oshima, H. Iimura, M.
Shibata, S. Hamada, H. Kusakari, M. Sugawara, M.
Ogawa, M. Nakajima, B.-J. Min, J.-C. Kim, S.-J.
Chae, and H. Sagawa: "High-Spin States of 145Sm",
ibid., A350, 185 (1994).

3.

Atomic and solid-state physics

M. Inokuti, M. Kimura, M. A. Dillon, and I.
Shimamura: "Analytic Representation of CrossSection Data", Adv. Atom. Mol. Opt. Phys., 33, 215(1994).
H. Qiu, E. Vagi, G. Safran, B. Pecz, P. B. Barna,and M. Hashimoto: "RBS Study of the Ni Film and
NijSi(100) Interface Prepared by Biased dc SputterDeposition", Bull. Univ. Electro-Commun., 7, 41(1994).
E. Vagi: "Channelling Study on the Lattice Locationof Hydrogen in Metals Utilizing a Nuclear Reaction" ,Hyperfine Interact., 84, 43 (1994).
R. Kadono, A. Matsushita, K. Nishiyama, and K.
Nagamine: "Relaxed Excited States and Anomalous
Hyperfine Structure of Muonium Centers in KBr",
ibid., p. 27l.
R. Kadono, S. Fujii, A. Matsushita, K. Nagamine, K.
Nishiyama, and S. Tanigawa: "Quantum Diffusion of
Muonium in GaAs with Shallow Donor Impurities",
ibid., 85, 79 (1994).
191

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., p. 259.
R. Kadono, A. Matsushita, K. Nishiyama, and K.
Nagamine: "Muon Radiolysis in Alkali Halides" ,ibid., 87, 979 (1994).
E. A. G. Armour, M. Plummer, and I. Shimamura:"Differential Scattering and Rotational Excitation in
Low-Energy Positron-H 2 Collisions", ibid., 89, 309(1994).
S. Kuboyama, S. Matsuda, T. Kanno, and T. Hirose:"Single Event Burnout of Power MOSFE's Caused
by Nuclear Reactions with Heavy Ions", IEEE
Trans. Nucl. Sci., NS-4l, 2210 (1994).
I. Hashimoto, J. Mitani, Y. Miyazaki, H. Yamaguchi,
E. Vagi, and M. Iwaki: "Recrystallization of Kr in
Kr-Implanted and Annealed Aluminum", J. Nucl.
Mater., 203, 269 (1993).
N. Toshima: "Unexpectedly Large Contribution of
C5+ Deep Bound States in C 6 + + H Collisions", J.
Phys. B, 27, L49 (1994).
N. Nakamura, T. Nabeshima, Y. Kanai, S. Kitazawa,
M. Koide, H. A. Sakaue, S. Ohtani, K. Wakiya, H.
Suzuki, T. Takayanagi, Y. Awaya, and T. Kambara:"Ejected Electron Spectra from the Triplet States of
0 4 + (ls 2 3l3l') Produced by 0 6 + + O 2 Collisions",
ibid., p. L 785.
H. Qiu, H. Nakai, M. Hashimoto, G. Safran, M.
Adamik, P. B. Barna, and E. Yagi: "Epitaxial
Growth and Characterization of Ni Films Grown on
MgO(OOl) by Biased Direct-Current Sputter Deposition" , J. Vac. Sci. Technol., A12, 2855 (1994).
M. Terasawa, T. Mitamura, T. Kohara, K. Ueda, H.
Tsubakino, A. Yamamoto, Y. Awaya, T. Kambara,
Y. Kanai, M. Oura, and Y. Nakai: "Infiuence of HighEnergy Heavy Ion Irradiation on Magnetic Flux Pinning in La1.85Sro.15Cu04", Physica, 235/240, 2805
(1994).
J. H. M. Beijersbergen, Q. Hui, and M. Takami: "Spectroscopy and Dynamics of Trapped Alkaline Earth
Atoms in Superfiuid Helium", Phys. Lett., A18l,
393 (1993).
W. G. Jin, M. Wakasugi, T. T. Inamura, T. Murayama,
T. Wakui, H. Katsuragawa, T. Ariga, T. Ishizuka, M.
Koizumi, and I. Sugai: "Isotope Shift and Hyperfine
Structure in LuI and WI", Phys. Rev. A, 49, 762(1994).
J.-Z. Tang, Y. Wakabayashi, M. Matsuzawa, S.
Watanabe, and I. Shimamura: "Critical Study of
Photo detachment of H- at Energies up to the n = 4
Threshold", ibid., p. 1021.
K. Hino, M. Nagase, H. Okamoto, T. Morishita, M.
Matsuzawa, and M. Kimura: "Double-Electron Excitation of H- by Fast Proton and Antiproton Impact", ibid., p. 3753.
M. Kimura, I. Shimamura, and M. Inokuti: "Single
192

and Double Ionization of Helium by Slow Protons
and Antiprotons", ibid., p. R4281.
J.-Z. Tang and I. Shimamura: "Mechanism of theEnhancement of Some High-Lying Resonance Series
in the Photoionization Spectra of Excited Helium",ibid., 50, 1321 (1994).
W. G. Jin, M. Wakasugi, T. T. Inamura, T. Murayama,
T. Wakui, H. Katsuragawa, T. Ariga, T. Ishizuka,
and I. Sugai: "Laser-rf Double-Resonance Spectroscopy of Refractory Elements: 183WI and 181TaI" ,ibid., p. 1920.
N. Toshima:"Ionization and Charge Transfer
of Atomic Hydrogen in Collision with Multiply
Charged Ions", ibid., p. 3940.
I. Shimamura and M. Kimura: "Analysis of theLifetimes and Fractions of Antiprotons Trapped in
Metastable States of Antiprotonic Helium", ibid., p.
5346.
R. Kadono, A. Matsushita, K. Nagamine, K.
Nishiyama, K. Chow, R. F. Kiefi, A. MacFarlane,
D. Schumann, S. Fujii, and S. Tanigawa: "Charge
State and Diffusivity of Muonium in n-type GaAs" ,Phys. Rev. B, 50, 1999 (1994).
K. H. Chow, R. L. Lichti, R. F. Kiefi, S. Dunsiger, T. L.
Estle, B. Hitti, R. Kadono, W. A. MacFarlane, J. W.
Schneider, D. Schumann, and M. Shelley: "Identification of Neutral Bond-Center Muonium in n-Type
Semiconductors by Longitudinal Muon Spin Relaxation", ibid., p. 8918.
R. Kadono, A. Matsushita, R. M. Macrae, K.
Nishiyama, and K. Nagamine: "Muonium Centers
in Crystalline Si and Ge under Illumination", Phys.
Rev. Lett., 73, 2724 (1994).
E. Vagi: "Lattice Location Study on Hydrogen in Metals by Means of Channelling Method Utilizing Nuclear Reaction 1H(l1 B, 0:)0:0:", RIKEN Rev., No.4,
p. 49 (1994).
R. Kadono: "Muonium Centers in Semiconducors
under Illumination", Solid State Physics (Kotai
Butsuri), 29, 817 (1994).
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", Trans. Mat. Res. Soc.
Jpn., 17, 393 (1994).
4.

Radiochemistry, radiation chemistry, and radiation biology

Y. Itoh, K. Lee, T. Nakajyo, A. Goto, A. Nakanishi, M.
Kase, I. Kanazawa, Y. Yamamoto, and N. Oshima:"Slow Positron Production Using the RIKEN AVF
Cyclotron", Appl. Surf. Sci., 85, 165 (1994).
W. Li, Y. Ohkubo, S. Ambe, Y. Kobayashi, M.
Iwamoto, H. Maeda, and F. Ambe: "Study on the
Nuclear Reactions of 93Nb, 181Ta, and 197 Au Induced by Secondary Neutrons in 40MeV /nucleon

40 Ar Ion Collisions", Chem. Lett., 1994, 277.
Y. Itoh, H. Murakami, and A. Kinoshita: "Positron
Annihilation Study on Nanometer Cavities in Porous
Silicon", Hyperfine Interact., 84, 121 (1994).
Y. Kobayashi, K. Asai, T. Okada, and F. Ambe:"Mossbauer and Magnetization Studies on the Ferromagnet Fe3-xRuxSi", ibid., p. 131.
K. Ando: "Present Status and Future Prospect ofParticle Radiobiology", Isotope News, No. 471, p.
2 (1993).
S. Ambe: "Mossbauer Study of Iron in Soybean Hulls
and Cotyledons", J. Agric. Food Chern., 42, 262(1994).
K. Ando: "Current Status of Biological Studies for
Heavy Particle Radiotherapy", J. Jpn. Soc. Ther.
Radiol. Oncol., 6, 1 (1994).
K. Asai, Y. Ohkubo, T. Okada, Y. Yanagida,
Y. Kawase, S. Uehara, S. Ambe, and F.
Ambe: "A Study on Hyperfine Magnetic Field at
117In( -+ l17 Cd) in Fe304 by ,-, Time-Differential
Perturbed Angular Correlation", J. Phys. Soc. Jpn.,
63, 1677 (1994).
Y. Itoh, H. Murakami, and A. Kinoshita: "Characterization of Porous Silicon by Positron Annihilation" ,J. Phys., (Paris), 3, 193 (1993).
S. Y. Chen, S. Ambe, and F. Ambe: "Preparation of aRadioactive Multitracer Solution from Iron Foil Irradiated by 80 MeV/nucleon 16 0 Ions", J. Radioanal.
Nucl. Chem. Lett., 186, 113 (1994).
K. Kimura: "A Fast Decay Measurement of Ion Induced Luminescence: Competition between Radiative and Nonradiative Annihilations of STE Produced by Ion Irradiation of BaF 2 Single Crystal",
Nucl. Instrum. Methods Phys. Res., B90, 100 (1994).
Y. Minai, Y. Takahashi, T. Ozaki, M. Ishibashi, S.
Ambe, M. Iwamoto, M. Yanokura, H. Maeda, N.
Takematsu, F. Ambe, and T. Tominaga: "Multitracer Study on Formation of Metal-humate Complexef? and Their Adsorption on Minerals", Proc. Int.
Trace Analysis Symp. '94, p. 71 (1994).
M. Yanaga, S. Enomoto, R. Hirunuma, R. Furuta, K.
Endo, S. Ambe, and F. Ambe: "Study on Uptake
and Excretion of Radioactive Nuclides in Rats Using
the Multitracer Technique", ibid., p. 73.
S. Enomoto, M. Yanaga, R. Hirunuma, R. Furuta, K.
Endo, S. Ambe, and F. Ambe: "Multitracer Studyon Distribution of Radioactive Nuclides in Rats",
ibid., p. 77.
K. Ando, S. Koike, M. lizuka, T. Aruga, N. Hori,
W. Shimizu, T. Sugita, S. Murayama, T. Kanai, S.
Minohara, M. Sudou, and F. Yatagai: "Effects ofHigh LET Radiation on Murine Skin and Tumors",
Proc. 3rd Workshop on Physical and Biological Research with Heavy Ions, eds. K. Ando and T. Kanai,
NIRS-M-99, HIMAC-006 , Natl. Inst. Radiol. Sci., p.
61 (1993).
Y. Hyodo-Taguchi, T. Kanai, S. Minohara, and Y.

Furusawa: "Effects of Accelerated Carbon-Ion on the
Induction of Dominant Lethality in the Teleost Fish,
Oryzias latipes", ibid., p. 77.
K. Kimura: "Track-Depth and Time Resolved Dynamics of Excited States Created in Ion Tracks", Radiat.
Chem., 58, 33 (1994).
S. Ambe, T. Ohkubo, Y. Kobayashi, M. Iwamoto, M.
Yanokura, H. Maeda, and F. Ambe: "Transport ofTc(VII) and Re(VII) through a Supported Liquid
Membrane", Radiochim. Acta, 63, 49 (1993).
M. Kikuchi, S. Kitayama, S. H. Sjarief, and H.
Watanabe: "Plasmids in Several Strains of Deinococcus radiodurans", Radiat. Res., 139, 123 (1994).
F. Ambe: "Development and Applications of Multitracers", RIKEN Rev., No.4, p. 31 (1994).
K. Ando, K. Fukutsu, H. Tatsuzaki, and F. Yatagai:"Downsizing Effect of Irradiated Volume on Normal
Tissue Injuries", ibid., p. 43.
5.

Material analysis

J. Kawai and K. Maeda: "K X-Ray Measurements ofIron Compounds Using Imaging-Plate X-Ray Emission Spectrometer", Adv. X-Ray Chem. Anal. Jpn.,
25, 1 (1994).
K. Maeda and J. Kawai: "Interfering Line in Trace
Analysis by X-Ray Spectrometry: Radiative Auger
Satellites", ibid., p. 25.
J. Kawai, T. Nakajima, T. Inoue, H. Adachi, M. Yamaguchi, K. Maeda, and S. Yabuki: "Chemical Effects
on the Intensity of Ti K1] (Radiative Auger Satellite) X-Ray Fluorescence Spectra", Analyst, 119,601(1994).
S. Takagi, T. Nakamura, T. Kohno, N. Shiono, and F.
Makino: "Observation of Space Radiation Environment with EXOS-D", IEEE Trans. Nucl. Sci., 40,
1491 (1993).
T. Doke, M. Fujii, M. Fujimoto, K. Fujiki, T. Fukui,
F. Gliem, W. GuttIer, N. Hasebe, T. Hayashi, T.
Ito, K. Itsumi, T. Kashiwagi, J. Kikuchi, T. Kohno,
S. Kokubun, S. Livi, K. Maezawa, H. Moriya, K.
Munakata, H. Murakami, Y. Muraki, H. Nagoshi,
A. Nakamoto, K. Nagata, A. Nishida, R. Rathje,
T. Shino, H. Sommer, T. Takashima, T. Terasawa,
S. Ullaland, W. Weiss, B. Wilken, T. Yamamoto,T. Yanagimachi, and S. Yanagita: "The Energetic
Particle Spectrometer HEP Onboard the GEOTAILSpacecraft", J. Geomag. Geoelectr., 46, 713 (1994).
K. Tazaki, M. Aratani, S. Noda, P. J. Currie, and W. S.
Fyfe: "Microstructure and Chemical Composition of
Duckbilled Dinosaur Eggshell", Sci. Rep. Kanazawa
Univ. , 39, 17 (1994).
J. Kawai, H. Adachi, S. Hayakawa, S. Y. Zhen, K.
Kobayashi, Y. Gohshi, K. Maeda, and Y. Kitajima:"Depth Selective X-Ray Absorption Fine Structure
Spectrometry", Spectrochim. Acta, 49B, 739 (1994).

193

VIII. LIST OF PREPRINTS
1994
RIKEN-AF -NP
161 T. Horibata and N. Onishi: "Tilted Axis Rotating in 1820S Yrast"
162 S. Midorikawa, T. Kubo, and T. Cheon: "Folded Bifurcation in Coupled Asymmetric Logistic Maps"
163 S. A. Goncharov and A. A. Korsheninnikov: "Elastic and Inelastic Scattering p + 8He at EC.M. = 65 MeV"
164 H. Suganuma, S. Sasaki, and H. Toki: "Color Confinement, Quark Pair Creation and Dynamical ChiralSymmetry Breaking in the Dual Ginzburg-Landau Theory"
165 T. Nakamura, S. Shimoura, T. Kobayashi, T. Teranishi, K. Abe, Y. Doki, M. Fujimaki, N. Inabe, N.
Iwasa, K. Katori, T. Kubo, H. Okuno, T . Suzuki, I. Tanihata, Y. Watanabe, A. Yoshida, and M. Ishihara:"Coulomb Dissociation of a Halo Nucleus 11 Be at 72 A MeV"
166 I. Tanihata, D. Hirata, and H. Toki: "Are All Nucleus Spherical at the Drip Line?"
167 M. Sano and M. Wakai: "Hypernuclear Production in High-Energy Nuclear Collisions"
168 T. Otsuka, M. Ishihara, N. Fukunishi, T. Nakamura, and M. Yokoyama: "Neutron Hallo Effect on Direct
Neutron Capture and Photo Disintegration"
169 A. A. Korsheninnikov, M. V. Zhukov, M. Smedgerg, and T. Kobayashi: "Neutron Momentum Distributions
from Fragmentation of the Exotic Nucleus 8He"
170 H. Okuno, K. Asahi, H. Sato, H. Ueno, J. Kura, M. Adachi, T. Nakamura, T. Kubo, N. Inabe, A. Yoshida,
Y. Kobayashi, Y. Ohkubo, M. Iwamoto, F. Ambe, T. Shimoda, H. Miyatake, N. Takahashi, J. Nakamura,
D. Beaumel, D. J. Morrissey, W. D. Schmidt-Ott, and M. Ishihara: "Systematic Behavior of Ejectile Spin
Polarization in the Projectile Fragmentation Reaction"
171 H. Toki, H. Suganuma, and S. Sasaki: "Magnetic Monopole Condensation for Confinement and Chiral
Symmetry Breaking"
172 S. Sasaki, H. Suganuma, and H. Toki: "Dual Ginzburg-Landau Theory with QCD Monopoles for Dynamical
Chiral-Symmetry Breaking"173 "TMU jRIKEN Summer Institute on Unstable Nuclei"
174 I. Tanihata, D. Hirata, and H. Toki: "Are All Nucleus Spherical at the Drip Line?"
175 A. A. Korsheninnikov, E. Yu. Nikolskii, T. Kobayashi, D. V. Aleksandrov, M. Fujimaki, H. Kumagai, A. A.
Ogloblin, A. Ozawa, I. Tanihata, Y. Watanabe, and K. Yoshida: "Excited States in 12Be, Exotic Cluster
Structure?"
176 H. Ichie, H. Suganuma, and H. Toki: "QCD Phase Transition at Finite Temperature in the Dual GinzburgLandau Theory"
177 S. Shimoura, T. Nakamura, M. Ishihara, N. Inabe, T. Kobayashi, T. Kubo, R. H. Siemssen, I. Tanihata,
and Y. Watanabe: "Coulomb Dissociation Reaction and Correlations of Two Halo Neutrons"
178 A. A. Ogloblin: "Some Results and Open Problems in Spectroscopy of the Neutron Drip-line Nuclei"
179 K. Varga, Y. Suzuki, and I. Tanihata: "Microscopic Four-Cluster Description of the 9Li and 9C Mirror
Nuclei"194

180 S. Momota: "Mechanism of the Polarization Production by Means of the Tilted-Foil Technique Studied by,B-Radioactive Nuclei"
181 K. Arai, Y. Suzuki, and K. Varga: "Neutron-Proton Halo Structure of the 3.563 MeV 0+ State in 6Li"
182 S. Kim and S. Ohta: "Lattice QCD Calculation Using VPP50Q"
183 T. Morikawa, Y. Gono, K. Morita, T. Kishida, T. Murakami, E. Ideguchi, H. Kumagai, G. H. Liu, A.
Ferragut, A. Yoshida, Y. H. Zhang, M. Oshima, M. Sugawara, H. Kusakari, M. Ozawa, M. Nakajima, H.
Tsuchida, S. Mitarai, A. Odahara, M. Kidera, M. Shibata, J. C. Kim, S. J. Chae, Y. Hatsukawa, and M.
Ishihara: "Coulomb Excitation of 174Hf-Isomer-,-Ray Spectroscopy with High-Spin Isomer Beam"195

IX. PAPERS PRESENTED AT MEETINGS
1.

Accelerator
physics

development

andaccelerator

M. Niimura: "Plausible EM-Noise Source in theSpace", URSI Int. Symp., Tokyo, May (1994).
Y. Yano, T. Katayama, and RARF Accelerator Group:"Present Status and Future Plan of RIKEN Accelerator Research Facility", 4th European Particle Accel.
Conf., London, U.K., June (1994).
O. Kamigaito, A. Goto, Y. Miyazawa, T. Chiba, M.
Hemmi, S. Kohara, M. Kase, and Y. Yano: "Designof a New Type of Variable-Frequency RFQ Linac
with a Folded-Coaxial Resonator", 19th Linear Accelerator Meeting in Japan, Tokai, July (1994).
O. Kamigaito, A. Goto, Y. Miyazawa, T. Chiba, M.
Hemmi, S. Kohara, M. Kase, and Y. Yano: "Designof aNew Type of Variable-Frequency RFQ Linac
with a Folded-Coaxial Resonator", 17th Int. Linac
Conf., Tsukuba, Aug. (1994).
H. Okamura, N. Sakamoto, T. Uesaka, H. Sakai, K.
Hatanaka, A. Goto, M. Kase, N. Inabe, and Y.
Yano: "Technique for Rotating the Spin Direction at
RIKEN" , 8th Int. Symp. on Polarization Phenomena
in Nuclear Physics, Indiana, U.S.A., Sept. (1994).
M. Niimura and H. Amemiya: "A Compact PulsedPower Ion Source for Plasma Potential Diagnostics" ,Fall Meet. Phys. Soc. Jpn. , Shizuoka, Sept. (1994).
M. Kase, N. Inabe, and I. Yokoyama: "A Beam
Phase Monitor with Use of a Micro-Channel Plate
for the RIKEN Ring Cyclotron", Beam Instrumentation Workshop, Vancouver, Canada, Oct. (1994).
Y. Yano, T. Katayama, and RARF Accelerator Group:"RIKEN RI Beam Factory Project" , Tamura Symp.
on Accelerator Physics, Austin, U.S.A., Nov. (1994).
2.

Nuclear physics and nuclear instrumentation

I. Tanihata: "Study of Light Exotic Nuclei Using Radioactive Nuclear Beams", Int. School-Seminar on
Heavy Ion Physics, Dubna, Russia, May (1993).
A. A. Ogloblin: "Current Situation and Some New
Approaches in Studying of Exotic Nuclei", ibid.
T. Matsuzaki and K. Ishida: "Muon Facility at RAL
and Methods of Muonic X-ray Detection", RIKEN
Symp. on Muon Science 1993 (II): Medical and Biological Applications of Nondestructive Elemental
Analysis Using Muons, Wako, Dec. (1993).
H. Kitagawa and A. Ozawa: "Beta-Decays of A = 17
Isobars and Isospin Symmetry" , Symp. on Science ofBeams of Short Life Nuclei '93, Tanashi, Dec. (1993).
K. Asahi: "Production of Spin-polarized Radioactive Nuclear Beams and Investigation of Probe Isotopes Applicable to Material Science", Symp. on Science with Radioactive Nuclear Beams, Tokyo, Dec.
(1993).
H. Okuno: "Mechanizm of Spin Polarization in Pro196

jectile Fragmentation Reaction", ibid.
H. Ueno: "Measurement of Magnetic Moment for
Neutron-halo Nucleus 17B", ibid.
H. Izumi: "Measurement of Electric Quadrupole Moments for Neutron-rich Nuclei 14B and 15B", ibid.
H. Suganuma, S. Sasaki, and H. Toki: "Color Confinement, Quark Pair Creation and Dynamical ChiralSymmetry Breaking in the Dual Ginzburg-Landau
Theory", YITP Workshop on Dynamics of Quarks
and Hadrons, Kyoto, Dec. (1993).
H. Kitagawa, S. Tadokoro, Y. Nishino, and T. Suzuki:"Distributions of Perturbative Gluons in the MIT
Bag Model", ibid.
H. Kitagawa, A. Ozawa, and 1. Tanihata: "Reaction
Cross Sections of Isobars (A = 17) in the Glauber
Model", ibid.
K. Ishida: "RIKENjRAL Muon Facility: Expected
Beam Properties and the Experimental Equipments", ISIS Muon Users Group Meeting, Abindton,
U.K., Feb. (1994).
S. Yamaji: "Vibrations in Hot Nuclei", RIKEN Symp.
on Dynamics in Hot Nuclei, Wako, Feb. (1994).
H. Kitagawa, A. Ozawa, and I. Tanihata: "Isospin
Symmetry in Light Isobars (A = 17)", 49th Ann.
Meet. Phys. Soc. Jpn., Fukuoka, Mar. (1994).
T. Motobayashi: "Excitation Energy Spectrum for 14 0
Dissociation Reaction" , ibid.
N. Fukunishi: "Effective Interaction in Asymmetric
Nuclear Matter", ibid.
K. Sagara, A. Motoshima, T. Sugimitsu, H. Nakamura,and S. Morinobu: "Trial Experiment on a Blow-in
Type Gas Jet Target", ibid.
H. Suganuma, S. Sasaki, 'a nd H. Toki: "Color Confinement, q-q Pair Creation and Dynamical ChiralSymmetry Breaking in the Dual Ginzburg-Landau
Theory", ibid.
M. Yokoyama, T. Otsuka, and H. Sagawa: "Multipole
Giant Resonances in Neutron-rich Nuclei", ibid.
T. Suzuki and T. Otsuka: "Beta Decay and Magnetic
Moment in Neutron-rich Nuclei", ibid.
K. H. Kim, T. Otsuka, and M. Tohyama: "Variationof Nucleon Density in Reactions between Stable andUnstable Nuclei", ibid.
A. Odahara, Y. Gono, S. Mitarai, E. Ideguchi, 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, J. C. Kim, and S. J. Chae: "High-Spin
Isomer and Level Structure of 145Sm", ibid.
E. Ideguchi, A. Odahara, T. Shizuma, M. Kidera,
M. Shibata, S. Mitarai, Y. Gono, T. Morikawa, M.
Oshima, Y. Hatsukawa, and S. Hamada: "High-Spin
Isomer of 146Eu", ibid.
Y. Gono, M. Shibata, E. Ideguchi, A. Odahara, M.
Kidera, S. Mitarai, T. Morikawa, M. Oshima, Y.
Hatsukawa, H. Iimura, M. Shibata, and S. Hamada:"High-Spin States of 147Eu", ibid.
T. Horibata and N. Onishi: "Tilted Axis Rotating
States in 1820s Yrast", ibid.
T. Horibata and N. Onishi: "Tilted Axis Rotating
States in 1820S Yrast", Int. Symp. on Frontiers of
Nuclear Structure Physics, Wako, Mar. (1994).
H. Ueno: "Static Moments of Neutron-rich Nuclei
Measured with Spin-polarized Radioactive Beams",
ibid.
M. Tohyama: "E1 and E2 Giant Resonances in 220",
ibid.
H. Ueno: "Abrasion-induced Spin Polarization as aTool to Study Neutron-rich Nuclei", Int. Symp.
on Spin-Isospin Responses and Weak Process in
Hadrons and Nuclei, Osaka, Mar. (1994).
T. Ichihara, M. Ishihara, H. Ohnuma, T. Niizeki,
Y. Tajima, T. Yamamoto, K. Kato, S. Katoh, T.
Yamashita, Y. Fuchi, S. Kubono, M. H. Tanaka, H.
Okamura, S. Ishida, T. Uesaka, Y. Satou, and T.
Fujita: "( 12 C, 12 N) Reaction at E / A = 135 Me V asa Probe of Spin-Isospin Excitation", ibid.
T. Kishida: "ACQ System for New Detector Array ofGe", RIKEN Symp. on Nuclei under Extreme Conditions: Physics of High-Spin Isomer Beams, Wako,
Mar. (1994).
H. Okuno, K. Asahi, H. Sato, H. Ueno, J. Kura,
M. Adachi, T. Nakamura, T. Kubo, N. Inabe, A.
Yoshida, T. Ichihara, Y. Kobayashi, Y. Ohkubo, M.
Iwamoto, F. Ambe, T. Shimoda, H. Miyatake, N.
Takahashi, J. Nakamura, D. Beamel, D. J. Beaumel,
W.-D. Schmidt-Ott, and M. Ishihara: "Polarization
Mechanism of Projectile Fragment", 1994 Spring
Meet. Phys. Soc. Jpn., Fukuoka, Mar. (1994).
T. Wakui, M. Wakasugi, W. G. Jin, T. T. Inamura, T.
Murayama, H. Katsuragawa, T. Ariga, T. Ishizuka,
M. Koizumi, and I. Sugai: "Precise Measurementof Hyperfine Structure and Nuclear Moments in
180mTa by Means of Laser-rf Double Resonance Spectrosc9PY" , ibid.
A. Muta and T. Otsuka: "Study of Unstable Nuclei by
Deformed Woods-Saxon Potential", ibid.
H. Okuno: "Mechanism of Spin Polarization in Projectile Fragmentation Reaction", ibid.
H. Ueno: "Measurement of Magnetic Moment for 17B
by Using Spin Polarization in Projectile Fragmentation Reaction", ibid.
K. Sumiyoshi, H. Kuwabara, H. Toki, and H. Suzuki:"Various Equations of State at Finite Temperatureand the Evolution of Protoneutron Stars", ibid.
N. Aoi: "Beta Decay of Neutron Rich Nucleus 14Be",
ibid.
N. Nakao et al.: "Spectrometry of Several Tens Me V
Neutrons Penetrating Shields Using Organic Liquid Scintillator at 90 MeV AVF Cyclotron Facility,
TIARA", 8th Int. Conf. on Radiation Shielding, Arlington, Texas, U.S.A., Apr. (1994).
H. Suganuma: "Glue balls , Hybrids and Exotics",

RCNP Workshop on Hadron Physics with CooledStored GeV Proton Beams, Osaka, May (1994).
S. Yamaji: "Vibrations in Hot Nuclei on the Basis of
Self-consistent Transport Theory", YITP Symp. on
Dynamics of Fluctuations, Kyoto, May (1994).
T. Ichihara, M. Ishihara, H. Ohnuma, T. Niizeki, T.
Yamamoto, K. Katoh, T. Yamashita, Y. Hara, Y.
Fuchi, S. Kubono, M. H. Tanaka, H. Okamura, S.
Ishida, T. Uesaka, and Y. Satou: "Spin-flip andNon-spin-flip Isovector Excitations Observed in the2
C, 12 N) Reactions at E/A = 135 MeV and the3
C, 13 N) Reactions at E/A = 100 MeV", Nucleus
Nucleus Collisions V, Taormina, Italy, May/June(1994).
A. Ozawa, G. Raimann, R. N. Boyd, J. J. Kolata, F.
Chloupeck, K. Yoshida, M. Fujimaki, T. Kobayashi,
Y. Watanabe; I. Tanihata, S. Kubono, and K.
Kimura: "Beta-Delayed Neutron Decay of 19C and
Its Astrophysical Implications", ibid.
A. Ozawa, I. Tanihata, T. Kobayashi, O. Yamakawa,
K. Ornata, N. Takahashi, T . Shimoda, K. Sugimoto,D. Olson, W. Christie, and H. Wieman: "Interaction Cross Sections and Radii of 11 C and 12N and
Effective Deformation Parameters in Light Mirror
Nuclei", ibid.
K. Sugawara-Tanabe: "The Revival of L-S Coupling
Scheme in Superdeformation", Int. Conf. in Perspectives for the Interacting Boron Bode, Padova, Italy,
June (1994).
A. A. Korsheninnikov: "Experimental Study of Neutron Rich Helium Isotopes and Observation of 1OHe",
Symp. on Science of Short-Lived Nuclear Beam, INS,Tokyo, June (1994).
T. Kishida: "High Spin Isomer Beam at RIKEN: Current Status and Future Plan", Physics Seminar of
Lund Univ., Lund, Sweden, July (1994).
K. Masuda, T. Doke, J. Kikuchi, and H. Okada:"Performance of an Ionization Chamber Filled with
Liquid Xenon Doped with Organic Molecules as a
Gamma-Ray Detector", SPIE's 1994 Int. Symp. on
Optics, Imaging, and Instrumentation, San Diego,
U.S.A., July (1994).
T. Kishida: "Current Status on Crystal Balls in Europe", 2nd Workshop on ')'-spectroscopy Collaborations of the JAERI Tandem Booster, Tokai,' July
(1994).
W. G. Jin, T. Ariga, M. G. Hies, T. T. Inamura, T.
Ishizuka, H. Katsuragawa, T. Murayama, J. Z. Ruan,
I. Sugai, M. Wakasugi, and T. Wakui: "Nuclear
Moments of 179Ta and 180mTa", 2nd China Japan
Joint Symp. on Nuclear Physics, Beijing, China,
Aug./Sept. (1994).
J . Kasagi: "Hot Nuclei; Gamma-ray and Particle
Emission", ibid.
Y. Gono: "Production and Application of High-Spin
Isomer Beams" , ibid.
T. Horibata and N. Onishi: "Tilted Axis Rotation

e
e

197

Studied by Self-consistent Cranking Model", ibid.
M. Kurokawa: "Study of 0: Decays in the 40 Ar + 232Th
Reaction Using the RIKEN Gas-Filled Separator IIHigh Resolution Position Sensitive Detector", Tours
Symp. on Nuclear Physics II, Tours, France, Aug.
(1994).
T. Motobayashi: "Coulomb Dissociation Experimentsof Astrophysical Interest", ibid.
H. Okada, M. Shinoda, T. Komiyama, K. Hasuike, J.
Kikuchi, T. Doke, K. Masuda, M. Suzuki, and S.
Konno: "Time Stability of Liquid Xenon Photoionization Detectors", Fall Meeting Phys. Soc. Jpn.,
Shizuoka, Sept. (1994).
N. Ishida, K. Masuda, H. Okada, T. Komiyama, and
T. Doke: "Measurements of Attenuation Lengths of
Scintillation Light in Liquid Rare Gases", ibid.
T. Ariga, M. Wakasugi, W. G. Jin, T. T. Inamura, T.
Wakui, T. Murayama, T. Ishizuka, H. Katsuragawa,
J. Z. Ruan, and 1. Sugai: "Measurement of Nuclear
Moments in 179Ta", ibid., Yamagata, Sept./Oct.
(1994).
T. Morikawa, Y. Gono, T. Kishida, E. Ideguchi, K.
Morita, A. Yoshida, H. Kumagai, G. H. Liu, Y. H.
Zhang, A. Ferragut, M. Ishihara, T. Murakami, M.
Oshima, Y. Hatsukawa, M. Sugawara, H. Kusakari,
M. Ogawa, M. Nakajima, H. Tsuchida, S. Mitarai, A.
Odahara, M. Kidera, M. Shibata, J. C. Kim, and S.
J. Chae: "First Observation of K-Isomer COULEXwith 174Hf Isomer Beam", ibid.
T. Morikawa and Y. Gono: "Nuclear Spectroscopy by
Means of Short Lived Isomer Beams", ibid.
E. Ideguchi, A. Odahara, M. Kidera, M. Shibata, S.
Mitarai, Y. Gono, T. Kishida, T. Morikawa, M.
Oshima, Y. Hatsukawa, S. Hamada, S. Iimura, H.
Iimura, M. Shibata, and Y. Kimura: "High-Spin Isomer of 148Tb", ibid.
H. Kitagawa and A. Ozawa: "Beta-Decay of NeutronRich Nuclei, 17B and 19C", ibid.
A. Motoshima, K. Sagara, H. Nakamura, T. Sugimitsu,
and S. Morinobu: "Development of a High-Pressure
Gas-Jet Target", ibid.
Y. Sugaya, D. Ashery, J. Chiba, H. Ito, K. Kimura, Yu.
T. Kieselev, S. Kouda, K. Miyano, T. Murakami,
T. Nagae, Y. Nakai, M. Nomachi, H. Ochiishi, S.
Sawada, M. Sekimoto, T. Suzuki, K. H. Tanaka,
M. K. Vlasov, Y. Yamanoi, K. Yasuda, and Y.
Yoshimura: "Subthreshold Antiproton Production
in o:A Reaction", ibid.
Y. Satou: "Deuteron Polarimeter at RIKEN", ibid.
A. Muta and T. Otsuka: "Structure of 11 Be", ibid.
H. Sato: "Polarization of Xe Nuclear Spin by Using
the Optical Pumping Method", ibid.
N. Nishimori, T. Fujita, A. Motoshima, F. Wakamatsu,
H. Akiyoshi, K. Maeda, H. Nakamura, K. Sagara,
and T. Nakashima: "Polarization Measurement of
12 MeV Polalized Neutron Beam", ibid.
D. Hirata: "Study of the Triaxial Deformation Using
the Relativistic Mean Field Theory", ibid.

198

K. Matsuta, T. Minamisono, M. Fukuda, Y. Nojiri,
M. Tanigaki, M. Mihara, T. Onishi, T. Yamaguchi,
A. Harada, M. Sasaki, T. Miyake, S. Fukuda, K.
Yoshida, A. Ozawa, T. Kobayashi, 1. Tanihata, J. R.
Alonso, G. F. Krebs, and T. J. M. Symons: "Magnetic Moment of Proton-Rich Nucleus 9C", ibid.
K. Matsuta, T. Minamisono, M. Fukuda, Y. Nojiri, S.
Fukuda, T. Izumikawa, M. Tanigaki, M. Nakazato,
M. Mihara, T. Onishi, T. Yamaguchi, T. Miyake,
M. Sasaki, A. Harada, T. Ohtsubo, K. Yoshida, A.
Ozawa, T. Kobayashi, 1. Tanihata, J. R. Alonso, G.
F. Krebs, and T. J. M. Symons: "Asymmetry Parameter of 23Mg Beta Decay", ibid.
Y. Sugahara: "A New Parameter Set with Mass Number Dependence in the Relativistic Mean Field Theory", ibid.
N. Fukunishi: "Effective Interaction in Asymmetric
Nuclear Matter II", ibid.
M. Yokoyama, T. Otsuka, H. Sagawa, and N.
Fukunishi: "Octupole Giant Resonances in Unstable Nuclei", ibid.
K. Sumiyoshi and H. Toki: "Equation of State of Supernova Matter and Protoneutron Stars", ibid.
A. Ozawa, G. Raimann, R. N. Boyd, J. J. Kolata, F.
Chloupeck, K. Yoshida, M. Fujimaki, T. Kobayashi,
Y. Watanabe, 1. Tanihata, S. Kubono, and K.
Kimura: "Beta-Delayed Neutron Decay of 19C and
17B", ibid.
T. Horibata and N. Onishi: "Signature Mixing inTilted Axis Rotating States", ibid.
T. Ichihara, M. Ishihara, H. Ohnuma, T. Niizeki, Y.
Yamashita, T. Yamamoto, Y. Fuchi, S. Kubono, M.
H. Tanaka, H. Okamura, S. Ishida, S. Miyamoto,and H. Toyokawa:"Spin-dipole Resonance of
12B Observed in the Charge-Exchange Reaction
12C(12C,12N)12B at E/A = 135 MeV", ibid.
K. Asahi: "Nuclear Magnetic Dipole and Electric
Quadrupole Moments of Neutron-rich Nuclei", ibid.
H. Ueno: "Measurement of Magnetic Moment for 17N
by Using Spin Polarization in Projectile Fragmentation Reaction", ibid.
H. Suganuma, H. Ichie, and H. Toki: "Multi-flux-tube
System in the Dual Ginzburg-Landau Theory and
Quark-Gluon-Plasma Formation", ibid.
T. Suzuki and T. Otsuka: "Beta Decay in A = 11
Nuclei", ibid.
H. Okamura, S. Ishida, N. Sakamoto, H. Otsu, T.
Uesaka, T. Wakasa, Y. Satou, S. Fujita, H. Sakai,
T. Niizeki, K. Katoh, T. Yamashita, Y. Hara, H.
Ohnuma, T. Ichihara, and K. Hatanaka: "Tensor
Analyzing Power of the 12C(d,2He)12B Reaction at
270 MeV", ibid.
A . A. Korsheninnikov: "Spectroscopic Studies of Light
Systems Far from Stability Valley and Beyond DripLine. Results", ibid.
E. Yu. Nikolskii: "Spectroscopic Studies of Light Systems Far from Stability Valley and Beyond DripLine. Experimental System", ibid.

T. Ichihara: "Nuclear Reactions and Spectroscopies
using the Spectrograph SMART", Jpn. Phys. Soc.
Meet., Symp. of Frontier of the Nuclear Spectroscopy, Yamagata, Sept.jOct. (1994).
H. Okamura, S. Ishida, N. Sakamoto, H. Otsu, T.
Uesaka, T. Wakasa, Y. Satou, S. Fujita, H. Sakai,
T. Niizeki , K. Katoh, T. Yamashita, Y. Hara, H.
Ohnuma, T. Ichihara, and K. Hatanaka: "Tensor
Analyzing Power of the 12C(d,2He)12B Reaction at
270 MeV", 8th Int. Symp. on Polarization Phenomena in Nuclear Physics, Indiana, U.S.A., Sept.
(1994).
S. Ishida: "Construction of the Deuteron POLarimeter
DPOL at RIKEN", ibid.
K. Matsuta, S. Fukuda, T. Izumikawa, M. Tanigaki,
M. Fukuda, M. Nakazato, M. Mihara, T. Onishi, T.
Yamaguchi , T. Miyake, M. Sasaki, A. Harada, T.
Ohtsubo, Y. Nojiri, T. Minamisono, K. Yoshida, A.
Ozawa, T. Kobayashi, 1. Tanihata, J. R. Alonso, G.
F. Krebs, and T. J. M. Symons: "Spin Polarizationof 23Mg in 24Mg + Au, Cu and Al Collisions at 91
A Me V", ibid.
H. Suganuma, S. Sasaki, H. Ichie, and H. Toki: "Dual
Higgs Mechanism on Color Confinement and Glueballs" , RCNP Symp. on Quark Nuclear Physics with
GeV Cooler-Ring Protons and Beyond, Osaka, Sept.
(1994).
T. Nakagawa, K. Yuasa-Nakagawa, Y. Futami, K.
Furut aka , K. Matsuda, K. Yoshida, T. Mizota, Y.
Honjo, N. Tomita, T. Suomiyervi, W. Q. Shen, J.
Kasagi, T. Matsuse, and S. M. Lee: "Pre- and PostScission Charged Particle Multiplicity in Binary Decay Process for Medium Mass Nuclei", 3rd IN2P3RIKEN Symp. on Heavy Ion Collisions, Sinrinkohen,
Oct. (1994).
T. Motobayashi: "Applications of Coulomb Excitation
at Intermediate Energies" , ibid.
J. Kasagi: "Excitation Energy and Temperature of Hot
Nucl~i Produced in Incomplete Fusion" , ibid.
T.Ichihara: "Spin-Flip and Non-spin-flip Isovector Excitation Observed in the 2 C, 12 N) at E / A = 135
MeV and 3C,13N) at E/A = 100 MeV ChargeExchange Reactions", ibid.
Y. Gono: "Study of High-Spin States with Isomer
Beams", Joint France-Japanese Meet. Within theIN2P3-RIKEN Agreement" , ibid.
T. Otsuka: "Nuclear Structure Studies of Unstable Nuclei", ibid.
H. Kitagawa and A. Ozawa: "Beta-Decay of NeutronRich Nuclei, 17B and 19C" , 1st Int. Workshop
on Strucutre and Dynamics of Quantum ManyBody Systems, Non-Linearity and Collective Motions, Aizu-Wakamatsu, Oct. (1994).
A. A. Korsheninnikov: "Experimental Studies of Light
Neutron Rich Nuclei", Int. Symp. on Physics of Unstable Nuclei , Niigata, Oct./Nov. (1994).
A. Yoshida: "Measurement of Fusion Cross Section
with Neutron Halo Nuclei", ibid.

ee

M. Tohyama: "E1 and E2 Giant Resonances in 220",
ibid.
H. Izumi: "Electric Quadrupole Moments of 14B and
15B and Magnetic Moment of 17B", ibid.
K. Asahi: "Electromagnetic Moments of Unstable Nuclei Studied with Polarized Projectile Fragments",
ibid.
T. Otsuka: "Structure of Nuclei Far from Stability",ibid.
K. H. Kim, T. Otsuka, and M. Tohyama: "Transfer
and Fusion Reactions of Unstable Nuclei", ibid.
Y. Gono: "Gamma Spectroscopy with High-Spin Isomer Beams", ibid.
T. Motobayashi: "Coulomb Dissociation of 8B and Solar Neutrino Problem", ibid.
H. Toki: "Relativistic Many Body Theory for Unstable
Nuclei and Supernovae", ibid.
K. Matsuta, M. Fukuda, M. Tanigaki, T. Minamisono,
Y. Nojiri, M. Mihara, T. Onishi, T. Yamaguchi,
A. Harada, M. Sasaki, T. Miyake, S. Fukuda, K.
Yoshida, A. Ozawa, T. Kobayashi, I. Tanihata, J. R.
Alonso, G. F. Krebs, and T. J. M. Symons: "Magnetic Moment of Proton Drip-Line Nucleus 9C", ibid.
H. Sato: "Development of Polarized Xe Solid as a Polarizer for Unstable Nuclei", 5th Int. Workshop on
Ion-Guide Based Isotope Separation, Hakone, Nov.
(1994) .
H. Ueno: "Magnetic Moments of 17N and 17B and
Structure of Nuclei with Large Neutron Excess",ibid.
H. Izumi: "Measurement of Electric Quadrupole Moments of Neutron-rich Nuclei 14B and 15B", ibid.
K. Sumiyoshi: "Structure of Unstable Nuclei and Its
Applications" , RIKEN Symp. on Use of Supercomputers and Visualization, Wako, Nov. (1994).
H. Suganuma, S. Sasaki, H. Toki, and H. Ichie: "Dual
Higgs Mechanism for Quarks in Hadrons", YITP
Workshop on From Hadronic Matter to Quark Matter: Evolving View of Hadronic Matter, Kyoto, Nov.
(1994).
H. Okuno, K. Asahi, H. Sato, H. Ueno, J. Kura,
M. Adachi, T. Nakamura, T. Kubo, N. Inabe, A.
Yoshida, T. Ichihara, Y. Kobayashi, Y. Ohkubo, M.
Iwamoto, F. Ambe, T. Shimoda, H. Miyatake, N.
Takahashi, J. Nakamura, D. Beamel, D. J. Beaumel,
W.-D. Schmidt-Ott, and M. Ishihara: "Polarization
Mechanism of Projectile Fragment", Symp. on Science of Short-lived Nuclei 93, Tanashi, Dec. (1994).
3.

Atomic and solid-state physics

M. Takami and J. H. M. Beijersbergen: "Laser Spectroscopy of Atoms and Molecules in Superfluid Liquid Helium I", 48th Ann. Meet. Phys. Soc. Jpn.,
Sendai, Mar. (1993).
J. H. M. Beijersbergen and M. Takami: "Laser Spectroscopy of Atoms and Molecules in Superfluid Helium II" , ibid.
199

J. H. M. Beijersbergen, Q. Hui, and M. Takami: "Laser
Spectroscopy of Clusters in Superfiuid Helium", 1993
Fall Meet. Phys. Soc. Jpn., Okayama, Oct. (1993).
1. Shimamura: "Properties of Exotic Helium", Symp.
on the Theory of Dynamic Processes Involving Exotic Atoms, Yugawara, Feb. (1994).
T. Okada, K. Asai, N. Yamada, T. Matsumoto, Y.
Yamada, and Y. Kodama: "5 7 Fe Mossbauer Studies of YBa2Cu3.928Feo.o7208 Oriented with a High
Magnetic Field II", 49th Ann. Meet. Phys. Soc. Jpn.,
Fukuoka, Mar. (1994).
R. Kadono, A. Matsushita, K. Nishiyama, K.
Nagamine, S. Fujii, and S. Tanigawa: "Charge Stateand Diffusivity of Muonium in n-type GaAs", ibid.
Q. Hui, J. L. Persson, J. H. M. Beijersbergen, and M.
Takami: "Radiative Lifetimes of Atoms in Liquid
Helium", ibid.
J. L. Persson, Q. Hui, J. H. M. Beijersbergen, and M.
Takami: "Atoms in Liquid Helium: Two Different
Sites", ibid.
Y. Matsui, 1. Ida, M. Koide, N. Nakamura, Y. Kanai,
Y. Awaya, T. Nagata, T. Kambara, T. Takayanagi,
K. Wakiya, and S. Otani: "Measurement of EjectedElectron Spectra from Ne 6 +**", ibid.
1. Ida, Y. Matsui, M. Koide, N. Nakamura, Y. Kanai,
Y. Awaya, T. Nagata, T. Kambara, T. Takayanagi,
K. Wakiya, and S. Otani: "Measurement of EjectedElectron Spectra from 0 6 +** Produced by 0 6 + +Ne, Ar, N 2", ibid.
J.-Z. Tang, Y. Wakabayashi, M. Matsuzawa, S.
Watanabe, and 1. Shimamura: "Calculations of Photodetachment from H- Using the Hyperspherical
Close-Coupling Method", ibid.
K. Ando, T. Kambara, Y. Kanai, M. Oura, N. Nakai,
Y. Awaya, and Z. Yarning: "Lifetimes of Ne-Like Fe
Ion Measured by Beamfoil Spectroscopy", ibid.
E. Vagi: "Channelling Method: Studies on the Stateof Hydrogen and Inert Gas Atoms in Metals" , Symp.
on the Characterization of Defects, ibid.
1. Shimamura: "Properties of Exotic Helium", Int.
School Phys. Exotic Atoms, Erice, Sicily, Italy, Mar.
(1994).
R. Kadono: "Quantum Thnneling Diffusion of Muon
in Solids at Ultra-low Temperature-Atomic Diffusion
by its Wave Character" ,67th Natl. Meet. Chern. Soc.
Jpn. (Spring), Tokyo, Mar. (1994).
M. Terasawa, T. Mitamura, H. Tsubakino, A.
Yamamoto, T. Kohara, K. Ueda, Y. Awaya, T.
Kambara, Y. Kanai, M. Oura, and Y. Nakai: "Infiuence of High Energy Heavy Ion Irradiation on
Magnetic Flux Pinning in Oxide-Superconductors",
1994 Spring Ann. Meet. of Atomic Energy Society ofJapan, Tsukuba, Mar. (1994).
M. Kimura, 1. Shimamura, and M. Inokuti: "Double
and Single Ionization of He in Collisions with Antiprotons and Protons at Low-ke V Energies", Ann.
Meet. Div. Atom. Molec. Opt. Phys., Amer. Phys.
Soc., Crystal City, Virginia, U.S.A. Apr. (1994).
200

Y. Awaya and M. Oura: "Present Status of SPring8 and the Concept of the Atomic Physics Undulator Beamline at SPring-8", Workshop on Atomic
Physics at High Brilliance Synchrotron Sources, Argonne, U.S.A., Apr. (1994).
M. Kimura, 1. Shimamura, and M. Inokuti: "Double
and Single Ionization of He by Slow Protons and Antiprotons", 14th Int. Conf. Few Body Prob. Phys.,
Williamsburg, Virginia, U.S.A., May (1994).
J. H. M. Beijersbergen, Q. Hui, and M. Takami:"Alkaline-earth Atoms in Hen: the Existence of Bubble States", Symp. at the Int. Wissenschaftsforum
Heidelberg, Heidelberg, Germany, May (1994).
J. L. Persson, Q. Hui, and M. Takami: "Spectroscopy
and Dynamics of Neutral Atoms in Superfiuid Helium", ibid.
Y. Awaya: "Studies of Atomic Physics at the RIKEN
Accelerator Facility", Int. Workshop on Iron Group
Atoms in the Laboratory and Space, Lund, Sweden,
June (1994).
R. Hutton, S. Huldt, B. Nystrom, 1. Martinson,
K. Ando, T. Kambara, Y. Kanai, Y. Nakai, Y.
Awaya, and J. Sugar: "Experimental Lifetimes of the
3p2p Levels in Na-like Nb(Nb 30 +)", 14th Int. Conf.
on Atomic Physics (ICAP-XIV), Corolado, U.S.A.,
July/Aug. (1994).
J. L. Persson, Q. Hui, and M. Takami: "Spectroscopyof Metal Atoms in Superfiuid Helium", ibid.
M. Terasawa, T. Mitamura, T. Kohara, K. Ueda, H.
Tsubakino, A. Yamamoto, Y. Awaya, T. Kambara,
Y. Kanai, and M. Oura: "Infiuence of High Energy
Heavy Ion Irradiation on Magnetic Flux Pinning in
La1.85SrO.15Cu04", 4th Int. Conf. on Materials andMechanism of Superconductivity, and High Temperature Superconductors, Grenoble, France, July
(1994).
M. Takami: "Laser Spectroscopy in Superfiuid Helium:
Exotic Properties of Atoms, Molecules and Superfiuids", U.S.-Japan Seminar on Quantum Electronic
Devices and States of Matter, Napa, U.S.A., Aug.
(1994).
Q. Hui, J. L. Persson, M. Nakamura, and M. Takami:"Spectroscopy of Alkaline Earth Dimers in Liquid
Helium", Fall Meet. Phys. Soc. Jpn., Shizuoka, Sept.
(1994).
J. L. Persson, Q. Hui, M. Nakamura, and M. Takami:"Ionization Potential of Atoms in Superfiuid Helium", ibid.
N. Watanabe, S. Kravis, M. Oura, T. Kojima, Y.
Awaya, K. Okuno, and M. Kimura: "Characteristics of the RIKEN EBIS", ibid.
1. Shimamura and M. Kimura: "General Properties of
Adiabatic Potentials for Exotic Atoms", ibid.
T. Kambara, Y. Awaya, Y. Kanai, Y. Nakai, T. Kojima, O. Jagutzki, and H. Schmidt-Bocking: "Recoil
Ion Momentum Analysis in 8 MeV on+ -He Collisions", ibid.
Y. Bito, A. Ito, M. Imai, N. Imanishi, Y. Nakai, T.

Kambara, Y. Kanai, T. Kojima, and Y. Awaya:"Fragmentation of C 60 by Highly Charged Heavy Ion
Impact", ibid.
Y. Kanai, T. Kambara, Y. Nakai, M. Oura, S. Kravis,
and Y. Awaya: "Incident Charge-State Dependenceof Binary Encounter Peak Energy II", ibid.
T. Okada, Y. Noro, H. Kitazawa, Y. Kobayashi, and F.
Ambe: ,,61 Ni Mossbauer in Spinel Chromite", ibid.
N. Yamada, Y. Kobayashi, T. Okada, and T. Tatsumi:"Mossbauer Effect of 57Fe in YSr2Cu3-xFex07-a",ibid.
Y. Kanai, T. Kambara, Y. Awaya, H. Ida, Y. Matsui,
T. Takayanagi, K. Wakiya, N. Nakamura, M. Koide,
and S. Ohtani: "Ejected Electron Spectra from
Triplet States of Double Excited 0 4 + and Ne6 +" , 7thInt. Conf. on Physics of Highly Charged Ions(HCI94), Wien, Australia, Sept. (1994).
R. Hutton, S. Huldt, B. Nystrom, I. Martinson, K.
Ando, T. Kambara, Y. Kanai, Y. Nakai, Y. Awaya,
and J. Suger: "Beam-Foil Measurements on Highly
Ionized Nb and Zr at RILAC", ibid.
Y. Kanai, T. Kambara, M. Oura, Y. Nakai, and Y.
Awaya: "Binary Encounter Electron Peaks for 0°
Electrons in Collisions of Biq +", ibid.
Y. Yamazaki, K. Komaki, S. Sat aka, M. Imai, H.
Tawara, K. Kawatsura, Y. Kanai, D. R. Schultz, andC. O. Reinhold: "Binary Encounter Electrons Observed at Zero Degree in 1 MeV /u Au + He", ibid.
Y. Awaya, K. Ando, Y. Kanai, T. Kambara, M.
Oura, and Y. Nakai: "Atomic Physics Studies at the
RIKEN Accelerator Research Facility", 2nd AsianInt. Seminar on Atomic and Molecular Physics, Beijing, China, Oct. (1994).
I. Shimamura and M. Kimura: "Interactions of Atoms
with Antiprotons and Negative Mesons", ibid.
I. Shimamura: "Antiprotonic Atoms", 19th Meet. of
the Soc. for Atomic Collision Research, Tokyo, Oct.
(1994).
Y. ZO\J., Y. Awaya, C. P. Bhalla, T. Kambara, Y.
Kanai, M. Oura, Y. Nakai, K. Ando, A. Hitachi, and
S. Kravis: "L-Subshell Vacancy Production of Fast
Argon Ions in Solids", Int. Conf. on the Applicationof Accelerators in Research and Industry, Denton,
U.S.A., Nov. (1994).
I. Shimamura: "Bound States and Collision Processes
Due to Coulomb Interactions between Atoms and
Negatively Charged Hadrons", Symp. on Strong Interactions in Exotic Atoms, Tanashi, Nov. (1994).
4.

Radiochemistry, radiation chemistry, and radiation biology

K. Ando et al.: "Relative Biological Effectiveness of
Accelerated Carbon Ions on Experimental Thmors" ,41st Ann. Meet. of Radiat. Res. Soc., Dallas, U.S.A.,
Apr. (1993).
K. Ando: "Japanese Radiobiological Experience of
Heavy Ions", NIRS Int. Symp. on Heavy Charged

Particle Therapy, Chiba, June (1993).
Y. Hyodo-Taguchi, T. Kanai, S. Minohara, and Y.
Furusawa: "Effects of Accelerated Carbon-Ion on the
Induction of Dominant Lethality in the Teleost Fish,
Oryzias latipes", 36th Ann. Meet. Jpn. Radiat. Res.
Soc. , Hiroshima, Oct. (1993).
Y. Otsu, H. Murakami, and Y. !toh: "Positron Annihilation in Porous Grasses", 49th Ann. Meet. Phys.
Soc. Jpn., Fukuoka, Mar. (1994).
K. Kimura: "Luminescence Efficiencies of Auger-free
Luminescence and Self-Trapped Exciton of BaF 2,
and Projectile-ion Dependence on the Efficiencies",
ibid.
R. Hirunuma, R. Furuta, S. Enomoto, K. Endo,
A. Tanaka, M. Yanaga, S. Ambe, Y. Ohkubo, Y.
Kobayashi, M. Iwamoto, H. Maeda, and F. Ambe:"Study on Distribution of Radioactive Nuclides in
Rats Using a Multitracer Technique", RIKEN Symp.
on New Techniques for Utilization of RI as Tracers'94, Wako, Mar. (1994).
S. Ambe, Y. Ohkubo, Y. Kobayashi, M. Iwamoto, H.
Maeda, and M. Yanokura: "Study on Transport andDistribution of Elements in Plants", ibid.
S. Shibata, K. Watari, Y. Noda, S. Ambe, M. Iwamoto,
H. Maeda, and F. Ambe: "Simultaneous Analysis
on Solid-Liquid Adsorption Behavior of Various Elements Using Radioactive Multitracer: Non-ionic
Macro-reticular Copolymer and Activated Carbon
Fiber", ibid.
K. Ando et al.: "Homogeneity and Heterogeneity of
Carbon-12 Spread-Out-Bragg-Peak in Thmor Cell
Kill and Thmor Growth Delay", 42nd Ann. Meet.
of Radiat. Res. Soc., Nashville, U.S.A., Apr. (1994).
S. Y. Chen, S. Ambe, Y. Ohkubo, Y. Kobayashi, M.
Iwamoto, H. Maeda, N. Takematsu, and F. Ambe:"Adsorption Study of Metal Ions Using Radioactive
Multitracers", 3rd Int. Conf. on Methods and Applications of Radioanalytical Chemistry, Kailua-Kona,
U.S.A., Apr. (1994).
S. Ambe, Y. Ohkubo, Y. Kobayashi, M. Iwamoto,
H. Maeda, and Y. Yanokura: "Multitracer Studyon Transport and Distributions of Metal Ions in
Plants", ibid.
S. Ambe, S. Y. Chen, Y. Ohkubo, Y. Kobayashi, H.
Maeda, M. Iwamoto, M. Yanokura, and F. Ambe:"Multitracer, a New Tracer Technique: Its Principle,
Features and Application", ibid.
R. Hirunuma, R. Furuta, S. Enomoto, A. Tanaka,
K. Endo, M. Yanaga, S. Ambe, Y. Ohkubo, Y.
Kobayashi, M. Iwamoto, H. Maeda, and F. Ambe:"Studies on the Uptake and Distribution of Radioactive Nuclides in Organs of Rats Using a Multitracer Technique", 67th Natl. Meet. Chern. Soc. Jpn.
(Spring), Tokyo, Mar./ Apr. (1994).
Y. Takahashi, Y. Minai, S. Ambe, Y. Kobayashi, Y.
Ohkubo, M. Iwamoto, M. Yanokura, H. Maeda, S.
Shibata, N. Takematsu, F. Ambe, and T. Tominaga:"Multitracer Study on Behaviors of Metal Ions in the201

Aqueous System Containing Humic Acid and Clay
Minerals or Silicagel", ibid.
Y. Sato, J. Kurachi, K. Soga, A. Shinohara, M.
Furukawa, S. Kojima, Y. Ohkubo, F. Ambe, K.
Mukai, A. Yokoyama, T. Saito, and H. Baba: "Differential Recoil Ranges of Reaction Products in
the Interaction of Copper with Intermediate Energy
40 Ar, 14N Ions", ibid.
K. Mukai, A. Yokoyama, T. Saito, H. Baba, Y.
Ohkubo, A. Shinohara, M. Furukawa: "Incomplete
Fusion in the 141 Pr + 40 Ar System", ibid.
Y. Itoh, H. Murakami, and A. Kinoshita: "Positronium Formation and Annihilation in Porous Silicon",10th Int. Conf. on Positron Annihilation, Beijing,
China, May (1994).
Y. Itoh, K. Lee, T. Nakajyo, A. Goto, A. Nakanishi, M.
Kase, I. Kanazawa, Y. Yamamoto, and N. Oshima:"Slow Positron Production Using the RIKEN AVF
Cyclotron", 6th Int. Workshop on Slow-Positron
Beam Techniques for Solids and Surfaces, Makuhari,
May (1994).
R. Hirunuma, K. Endo, M. Yanaga, S. Enomoto, S.
Ambe, and F. Ambe: "Studies on the Distribution of Various Elements in Organs of Rats Using a
Multitracer Technique" ,9th Symp. on Biofunctional
Chemistry, Tokyo, May (1994).
M. Yanaga, R. Hirunuma, R. Furuta, S. Enomoto,
K. Endo, A. Tanaka, S. Ambe, Y. Ohkubo, Y.
Kobayashi, M. Iwamoto, H. Maeda, and F. Ambe:"Multitracer Studies on Uptake and Distribution ofRadioactive Nuclides in Organs of Rats", 31st Ann.
Meet. on Radioisotopes in the Physical Sciences andIndustries, Tokyo, July (1994).
M. Iwamoto, S. Ambe, Y. Ohkubo, Y. Kobayashi, H.
Maeda, M. Yanokura, and F. Ambe: "Productionof Multitracer Nuclides by Irradiation with a 84Kr
Beam", ibid.
Y. Itoh, K. Lee, A. Goto, N. Nakanishi, M. Kase, N.
Oshima, T. Nakajyo, I. Kanazawa, and Y. Ito: "SlowPositron Production Using RIKEN AVF Cyclotron" ,ibid.
S. Ambe, K. Takeshita, Y. Ohkubo, Y. Kobayashi, H.
Maeda, M. Iwamoto, and F. Ambe: "Multitracer
Study on Adsorption of Metal Ions on a-Fe203",
ibid.
K. Eguchi-Kasai, M. Murakami, H. Itsukaichi, K.
Fukutsu, T. Kanai, Y. Furusawa, K. Sato, H. Ohara,
and F. Yatagai: "The Role of DNA Repair on Cell
Killing by Charged Particles" ,30th COSPAR Meet.,
Hamburg, Germany, July (1994).
K. Kimura: "Excitation-Density Dependent Competition between Radiative and Nonradiative Annihilations of Core- and Self-trapped-Excitons Produced
by Ion Irradiation of a Single Crystal of BaF2", Gordon Conf., Newport, U.S.A., July (1994).
K. Kimura: "Track-Depth Resolved Dynamics of Helium Excimers along 4 MeV /amu N-ion Tracks in
Near-Liquid and Liquid Helium", ibid.
202

R. Hirunuma, K. Endo, M. Yanaga, S. Enomoto, S.
Ambe, and F. Ambe: "Multitracer Study on Behavior of Trace Elements in Rats", Hiroshima Int. Mini
Symp. on Molecular Recognition Involving Metal
Complexes, Hiroshima, July (1994).
M. Yanaga, S. Enomoto, R. Hirunuma, R. Furuta, K.
Endo, S. Ambe, and F. Ambe: "Study on Uptake
and Excretion of Radioactive Nuclides in Rats Using the Multitracer Technique", Int. Trace Analysis
Symp. '94, Hakodate and Sapporo, Aug. (1994).
S. Enomoto, M. Yanaga, R. Hirunuma, R. Furuta, K.
Endo, S. Ambe, and F. Ambe: "Multitracer Studyon Distribution of Radioactive Nuclides in Rats",
ibid.
K. Kimura and T. Yoshikane: "Formation Efficiencies and Decays of Outermost Core- and Self-trapped
Excitons in lon-Excited BaF 2 Single Crystal", 37th
Conf. Radiat. Chern., Sapporo, Sept. (1994).
K. Kimura: "A Prize Talk of This Society: TrackDepth and Time Resolved Dynamics of Excited
States Created in Ion Tracks", ibid.
H. Shibata, T. Furusawa, and K. Kimura: "Studyon Luminescence Mechanisms of BaF 2 by Means ofElectron-Pulse Radiolysis", ibid.
S. Ambe and F. Ambe: "Moss bauer Isomer Shifts ofDefect 119Sn Atoms with Ligands from Silver to Iodine", Eotvos Workshops in Science: Nuclear Techniques in Structural Chemistry, Budapest, Hungary,Sept. (1994).
Y. Ohkubo, Y. Kobayashi, S. Ambe, K. Asai, T.
Okada, and F. Ambe: "Local Structure and Valence of Impurity Ions in Oxides by TDPAC andMossbauer Emission Spectroscopy", ibid.
K. Kimura and T. Yoshikane: "Formation Efficiencies
and Decay Mechanisms of Outermost-core and Selftrapped Excitons in lon-Irradiated BaF 2 " , 1994 Fall
Meet. Phys. Soc. Jpn., Shizuoka, Sept./Oct. (1994).
K. Kimura and T. Yoshikane: "Track-depth Resolved
Dynamics of Excited States in Dense Argon at Low
Temperature", ibid.
Y. Hama, K. Hamanaka, H. Matsumoto, H. Kudoh, T.
Sasuga, and T. Seguchi: "Inhomogeneous Degradation of Polymers by X-rays, Gamma-rays and lonbeam as Studied by Micro-FT-IR", 9th Int. Meet.
on Radiation Processing, Istanbul, Turkey, Sept.
(1994).
S. Ambe, T. Shinonaga, H. Maeda, M. Iwamoto, S.
Uchida, and H. Yasuda: "Determination of Selective
Absorption Coefficient for Elements in Plants by aRadioactive Multitracer Technique." ,38th Symp. on
Radiochemistry, Shizuoka, Sept. (1994).
S. Shibata, K. Watari, Y. Noda, S. Ambe, M. Iwamoto,
H. Maeda, and F. Ambe: "Simultaneous Analysis
on Solid-Liquid Adsorption Behavior of Various Elements Using Radioactive Multitracer: Non-ionic
Macro-reticular Copolymer and Activated Carbon
Fiber", ibid.
N. Ito, N. Aoki, H. Harakawa, Y. Saito, K. Kimura,S. Ambe, M. Iwamoto, H. Maeda, and F. Ambe:"Study on the Ion Exchange Adsorption and Application to Analytical Chemistry on Superacid Resin
NAFION Using a Multitracer", ibid.
S. Ambe, Y. Iijima, M. Iwata, M. Takeda, M.
Takahashi, H. Maeda, M. Iwamoto, and F. Ambe:"Study on Extraction of Various Elements with
Crownether Using the Multitracer Technique", ibid.
S. Ambe, Y. Ohkubo, Y. Kobayashi, M. Iwamoto, H.
Maeda, and M. Yanokura: "Multitracer Study on
Transport and Distribution of Metal Ions in Plants" ,ibid.
K. Mukai, K. Takesako, H. Kusawake, Y. Sato, T.
Inoue, R. Kasuga, A. Yokoyama, T. Saito, H. Baba,
Y. Ohkubo, A. Shinohara, and M. Furukawa: "Incomplete Fusion of Intermediate Energy Induced by
Heavy Ions", ibid.
M. Iwamoto, S. Ambe, Y. Ohkubo, Y. Kobayashi, H.
Maeda, M. Yanokura, and F. Ambe: "Productionof Multitracer Nuclides by Irradiation with an 40 Ar
Beam", ibid.
M. Yanaga, R. Hirunuma, K. Endo, S. Enomoto, S.
Ambe, and F. Ambe: "Study on Distribution ofVarious Trace Elements in Rats Using the Multitracer
Technique (1): Uptake and Excretion Behaviour",ibid.
S. Enomoto, S. Ambe, F. Ambe, M. Yanaga, R.
Hirunuma, and K. Endo: "Study on Distributionof Various Trace Elements in Rats Using the Multitracer Technique (2): Metabolisms and Accumulations of Trace Elements in Various Tissues, Organs
and Body Fluids", ibid.
T. Ozaki, Y. Takahashi, Y. Minai , S. Ambe, M.
Iwamoto, H. Maeda, F. Ambe, S. Takematsu, andT. Tominaga: "Anomalous Adsorption Behavior ofRare Earths", ibid.
A. Shinohara, J. Kurachi, K. Mukai, Y. Sato, S. Kiryu,
S. Kojima, T. Saito, A. Yokoyama, Y. Ohkubo, M.
Furukawa, and F. Ambe: "Angular Distribution of
Recoil Products in the Heavy-Ion Reaction of Goldin the Intermediate Energy Range" , ibid.
K. Kikuchi, S. Nakanishi, K. Sueki, H. Nakahara, S.
Enomoto, and F. Ambe: "Pharmacokinetics Studyof Water-Miscible Fullerene by 14C Labeling", ibid.
M. Murakami, K. Eguchi-Kasai, H. Itsukaichi, K.
Fukutsu, K. Sato, F Yatagai, and T . Kanai: "Biological Effects of Heavy-Ion Irradiation on DNA DoubleStrand Breaks Repair Deficient Mutant Cell Line",
37th Ann. Meet. Jpn. Radiat. Res. Soc., Fukuoka,
Oct. (1994).
Y. Kagawa, F. Yatagai, M. Suzuki, Y. Kase, A.
Kobayashi, M. Watanabe, and F. Hanaoka: "Analysis of Mutations in the Human HPRT Gene Inducedby Accelerated Heavy-ion Irradiation" , ibid.
S. Kitayama, H. Takagi, M. Kohroku, and H. Ito:
"RecA Gene and Radioresistance of Deinococcus radiodurans", ibid.
H. Maezawa, T. Mori, F. Yatagai, T. Kanai, S.

Inokuchi, and H. Hanada: "Radiosensitivity of Human Skin Cells Irradiated with Heavy-Ion Beams",
ibid.
M. Yanaga, S. Enomoto, R. Hirunuma, K. Endo, S.
Ambe, and F. Ambe: "Study on Uptake and Distribution of Various Elements in Rats Using the Multitracer Technique (1)", 68th Natl. Meet. Chern. Soc.
Jpn. (Fall), Nagoya, Oct. (1994).
R. Hirunuma, K. Endo, M. Yanaga, S. Enomoto, S.
Ambe, and F. Ambe: "Study on Uptake and Distribution of Various Elements in Rats Using the Multitracer Technique (2)", ibid.
Y. Hama, K. Hamanaka, H. Matsumoto, H. Kudoh,
T. Sasuga, and T. Seguchi: "Relationship between
Energy Profile and Chemical Structural Change
in Polymers Irradiated by Ion-beams", 6th JapanChina Bilateral Symp. on Radiation Chemistry,
Tokyo, Nov. (1994).
K. Kimura: "Enhanced Decay Rates of Core Excitonsin Ion Irradiated BaF 2 and CsCI Single Crystals andIon Dependent Luminescence Efficiencies", ibid.
S. Kitayama, H. Takagi, M. Kohroku, and H. Ito:
"RecA of Deinococcus radiodurans" , 17th Ann. Meet.
Jpn. Mol. BioI. Soc., Kobe, Dec. (1994).

5.

Material analysis

K. Maeda and J. Kawai: "Analysis of Aqueous Solution by Ion-Induced X-Ray Spectrometry", 49th
Ann. Meet. of Phys. Soc. Jpn., Fukuoka, Mar.
(1994).
N. Arai, W. Sakamoto, and K. Maeda: "An Atempt
at Analysis of Trace Elements in Otoliths by PIXE",
Spring Meet. Jpn. Soc. Sci. Fisheries, Tokyo, Apr.
(1994).
N. Arai, W. Sakamoto, and K. Maeda: "Correlation
between Trace Element Concentrations and Ambient
Seawater Temperature in Red Sea Bream", ibid.
K. Sato, H. Honda, J. Jyunji, M. Yanokura, and M.
Aratani: "Analysis of Gas Tables as Fire Causeby Means of the Heavy-Ion Rutherford Scattering",
Japan Fire Society, Tokyo, May (1994).
K. Sato, H. Honda, J. Ushimaru, M. Yanokura, and M.
Aratani: "A Proof for the Gas Range under Operation as a Cause of Fire by Heavy-Ion Rutherford
Scattering", Symp. Fire Science and Engineering,Tokyo, May (1994).
A. S. Yukimatsu, S. Takagi, T. Terasawa, T. Kohno,
F. Makino, and M. Ejiri: "Structural Variationof Radiation Belt Associated with Solar Flare and
SC Event Observed by Radiation Monitor (RDM)
Aboard Akebono (EXOS-D)", 8th Int. Symp. on Solar Terrestrial Physics Dedicated to Solar Terrestrial
Energy Symp. (STEP), Sendai, June (1994).
A. S. Yukimatsu, M. Ejiri, S. Takagi, T. Terasawa,
T. Kohno, and F. Makino: "Structural Variationsof Radiation Belts Observed by Radiation Monitor (RDM) Aboard Akebono (EXOS-D)", Taos 10th203

Workshop on the Earth's Trapped Particle Environment, New Mexico, U.S.A., Aug. (1994).
K. Sato, H. Honda, J. Jyunji, M. Yanokura, and M.
Aratani: "Heavy-Ion Rutherford Scattering Applied
to the Fire Investigation", 38th Symp. Radiochemistry, Shizuoka, Sept. (1994).
K. Sato, H. Honda, J. Jyunji, M. Yanokura, and M.
Aratani: "Analysis of Gas Tables as Fire Causeby Means of the Heavy-Ion Rutherford Scattering",
42th Conf. Nat!. Fire Engineer, Tokyo, Oct. (1994).
K. Maeda and J. Kawai: "Satellite X-Rays Caused by
Radiative Auger Effect (RAE)", 12th PIXE Symp.,
Ikeda, Oct. (1994).
J. Kawai and K. Maeda: "Vertical Beam Line of204

RIKEN Heavy Ion Linear Accelerator", ibid.
N. Arai, W. Sakamoto, and K. Maeda: "Trace Element
Hard Tissues in Maline Life", ibid.
T. Kohno: "Observation of Anomalous and Solar Cosmic Rays in the Magnetosphere (ORCAS)", Workshop on Participation Oppotunity on the Brazillian Scientific Microsatellite, Sao Jose Dos Campos,
Brazil, Oct. (1994).
J. Kawai, S. Hayakawa, S. Y. Zhen, K. Kitajima, K.
Maeda, A. Nakao, H. Adachi, and Y. Gohshi: "Total
Reflection X-Ray Absorption Fine Structure of Semiconductor Wafers", 5th Workshop on Total Reflection X-Ray Fluorescence Spectroscopy and Related
Spectroscopical Methods, Tsukuba, Oct. (1994).

x. LIST OF SYMPOSIA(Jan.- Dec. 1994)
1) Dynamics of Hot Nuclei
21- 22 Feb., Wako, RIKEN, Cyclotron Lab.
2) New Techniques for Utilization of RI as Tracers '94
28 Mar., Wako, RIKEN, Nuclear Chemistry Lab.
3) Third IN2P3 Symposium in Heavy Ion Collisions
24- 28 Oct., Shinrin-Koen, Saitama, Radiation Lab.
4) 5th International Workshop on Ion-guide Based Isotope Separation
5-7 Nov., Hakone-Gora, Cyclotron Lab.
5) Advanced Positron Technologies and Their New Application
15-16 Dec., Wako, RIKEN, Nuclear Chemistry Lab.

205

XI. LIST OF SEMINARS(Jan.- Dec. 1994)"Computer Simulation of High Current Beam Dynamics in Particle Accelerator"

Radiation Lab., Cyclotron Lab., andLinear Accelerator Lab.

1) T. Horibata, Aomori Univ./RIKEN (Aomori/Saitama), 17 Jan.
"Tilted Axis Rotating States in 1280s Yrast"2) H. Suganuma, RIKEN (Saitama), 3 Feb.
"Color Confinement, Quark Pair Creation and
Dynamical Chiral-Symmetry Breaking in the Dual
Ginzburg-Landau Theory"3) S. Nonose, Univ. Tokyo (Tokyo), 16 Feb.
"Cluster Collision"
4)

S. Midorikawa, Meiji Univ. (Tokyo), 23 Feb.
"Folded Bifurcation in Coupled Asymmetric Logistic Maps"

5) K. Varga, RIKEN (Saitama), 6 Apr.
"Microscopic Multicluster Description of the
Neutron-rich Helium Isotopes"
6)

K . Tanaka, RCNP, Osaka Univ. (Osaka), 8 Apr.
"Higher Order Quantum Correction on the Relativistic Many-Body Problem and Behavior of HighDensity Matter"7) N. Ohnishi, Univ. Tokyo (Tokyo), 18 Apr.
"Periodic Solution and Quantization"8) Y. Yoshii and T. Kajino, NAO, Theoretical Astrophysics (Tokyo), 10 May"The Creation of Light Elements - Cosmology andCosmic Rays"
9) Dr. S. Kim, Argonne Natl. Lab. (USA), 16 May"Quenched QCD Spectrum Calculation"10) G . Mathews, NAO, Theor. Astrophys. / Lawrence
Livermore Natl. Lab. (Tokyo/USA), 17 May"Cosmic Phase Transitions and Primordial
N ucleosynthesis"

14) D. J. Rowe, Univ. of Toronto (USA), 11 July
"A Vector Coherent State Representation of theFive-Dimensional Harmonic Oscillator: Algebraic
Models of Nuclear Collective Motion"15) J. R. Bennett, Tohoku Univ. (Sendai), 12 July
"Interacting Boson Model Description of Dissipation in Fusion and Fission"16) H. Schuessler, Texas A&M Univ.jINS (USA/Tokyo), 1 Aug.
"Charged Particle Crystals and On-line Spectroscopy"17) M. Fujiwara, RCNP (Osaka), 4 Aug.
"Microscopic Structures of Spin-Isospin Excitations in Nuclei"18) Y. T. Ogaessian, Dubna Joint Inst. Nucl. Res.
(Dubna), 29 Sept.
"Synthesis of Super Heavy Element at Dubna"19) N. D. Dang, Vietnam Atomic Energy Commission/INS (Vietnam/Tokyo) , 17 Oct.
"Width of Giant Dipole Resonance in Hot Nuclei"20) H. C. Flocard, Div. Phys. The. I. P. N. Orsay (Orsay), 12 Oct.
"Microscopic Calculations of Superdeformed
Bands"

21) S. S. Kapoor, Bhabha Atomic Res. Cent. (India),
18 Oct.
"Study of Dynamics in Heavy Ion Fusion Fission
Reactions"22) C. Bertulani, Inst . Fisica Univ. Federal do Rio deJaneiro (Brazil), 7 Nov.
"Multiphonon Excitation of Giant Resonance"
23)11) Y. Ogawa, INS/RIKEN (Tokyo/Saitama), 24
May"Momentum Distribution of a Fragment fromBreakup Reaction of 11 Li and Neutron Correlation"

A. Shirokov, Inst. Nucl. Phys., Moscow State
Univ. (Moscow), 8 Nov.
"J-Matrix Approach and Three-Body Structure of
11 Li"

12) A. Ono, Kyoto Univ. (Kyoto) , 20 May"Fragment Flow on Heavy Ion Reactions"24) T. Izumoto, Rikkyo Univ. (Tokyo), 21 Nov.
"Coupled Channels Analyses of Scattering andFusion Cross Sections of 16 0 + 152, 154 Sm , 186W
System at Sub- and Near-Barrier Energies"

13) Y. Batygin, RIKEN (Saitama), 27 May

25) W. von Oertzen, Hahn-Meitner Inst. (Germany),206

22 Nov.
"Spectroscopy of lOHe and Other Neutron Rich
Nuclei by Two Body Reactions"
26) L. Zhang, IMPAS (China), 22 Nov.
"Possibility of Study the Neutron-Rich Nuclides
of Heavy Mass Region with IGISOL"
27) N. Van Giai, Inst. Phys. Nucl., Univ. Paris-Sud(Orsay), 1 Dec.
"Particle Decay of Isovector Giant Resonances"
28) S. Nagamiya, Columbia Univ. (USA), 6 Dec.
"High Energy Frontier in Heavy Ion Physics"29) E. Suraud, Univ. of Toulouse (France), 16 Dec.
"Multifragmentation in Heavy-Ion Collisions Mean Field and Fluctuations"30) T. Suzuki, Fukui Univ.jRIKEN (Fukui/Saitama),
19 Dec.
"The Macroscopic Model of Giant ResonanceStates in Neutron-rich Nuclei""Interactions of Highly Charged Ions with Electrons, Atoms, and Negative Ions"
8) Sung-Ho Suck Salk, Pohang Univ. Sci. Technol.
(Korea), 3 June
"Berry Phase in Atom-Diatom Collisions"9) R. I. Hall, Univ. Pierre et Marie Curie (France),
10 Aug.
"One-Photon Double Ionization of Rare-Gas 'Atoms in the Threshold Region"10) E. E. Nikitin, Israel Inst. of Tech. (Israel), 7 Oct.
"Quasi classical Theory of Scattering of PolarizedAtoms"
11) J. Eichler, Hahn Meitner Inst. (Germany), 14
Nov.
"Radiative Electron Capture in Relativistic
Atomic Collisions"
Nuclear Chemistry Lab.

31) K. Sumiyoshi, RIKEN (Saitama), 20 Dec.
"The Relativistic Mean Field Theory for Unstable
Nuclei and the Birth of Neutron Stars"

1) K. Lee, Univ. of Texas Arlington (USA), 13 Jan.
"Study of Metal Overlayer System Using Positron(e+) Beam"

32) R. Boyd, Ohio State Univ. (USA), 27 Dec.
"Recent Studies in Primordial and Stellar Nucleosynthesis"2) A. N. Garg, Nagpur Univ. (India), 26 Apr.
"N uclear Analytical Methods in Environmental
and Biomedical Studies"

Atomic Physics Lab.

3) R. Amano, Kanazawa Univ. (Kanazawa), 30 Apr.
"RI and Radiopharmaceuticals"1) M. Stockli, Kansas State Univ. (USA), 10 Jan.
"The KSU-CRYEBIS: Its Status, Its Potential,
and Its Applications"
2) Chii-Dong Lin, Kansas State Univ. (USA), 13 Jan.
"Orientation and Alignment in lon-atom Collisions"
3) H. Marxer, Oxford Univ. (UK), 7 Feb.
"R-Matrix Calculations for Atoms in Crossed
Fields"4) B. Zhou, Kansas State Univ. (USA), 7 Feb.
"Photodetachment of H- in Static Electric Field"5) C. Zhu, Inst. Mol. Sci. (Aichi), 15 Feb.
"The Two-State Curve-Crossing Problem"6) I. A. Sellin, Univ. of Tennessee (USA), 15 Apr.
"Double Ionization in He at Intermediate andHigh Photon Energy"7) L. P. Presnyakov, Lebev Phys. Inst. (Russia), 16
May4) A. Weiss, Univ. of Texas Arlington (USA), 18 May"Study of Ultrathin Metal Films on Metal Using Positron Annihilation Induced Auger Electron
Spectroscopy (PAES)"
5) G. Zhang, Shanghai Inst. Nucl. Res. (China), 28
July"Buckyball and Iron Nanoparticles"
6) K. Kikuchi, Tokyo Metropol. Univ. (Tokyo), 28
July"Fullerene Family"
7) J. V. Kratz, Johannes Gutenberg-Univ. Mainz(Germany), 14 Sept.
"Periferal and Central Heavy-ion Collisions at
Around 1 GeV / A Studied with the Large Area
Neutron Detector LAND"
8) P. Giitlich, Johannes Gutenberg-Univ. Mainz(Germany), 30 Sept.
"Recent Development in Spin-crossover and
LIESST /NIESST Research"
2079) K. Yoshihara, Tohoku Univ. (Sendai), 12 Oct.
"Chemistry of Technetium and Rhenium"10) Y. Hamajima, Kanazawa Univ. (Kanazawa), 19
Oct.
"Analysis of Complex Gamma-ray Spectra"

20811) H.-E. Mahnke, Hahn-Meitner Inst. (Germany), 4
Nov.
"Radioactive Nuclei in Material Science Research"
12) S. Kondo, Nihon Mediphysics (Chiba), 7 Dec.
"Radiopharmaceuticals with Tc-99m: Present
and FUture"

XII. LIST OF PERSONNELRIKEN Accelerator Research Facility
ISHIHARA Masayasu ;£ @. .IE ~ (Facility Director)
AWAYA Yohko ~ ~ ?fI. -f- (Vice Facility Director)
YANO Yasushige *- ff 17: !i (Vice Facility Director)
Linac Division
CHIBA Toshiya =f ~ ~IJ EX
HEMMI Masatake ~ Jt rec it
KASE Masayuki 1.10 iii ~ Z
MIYAZAWA Yoshitoshi g if{ f~ fiX*1= -=Ring Cyclotron Division
FUJITA Jirou Di EB.M
IKEGAMI Kumio H!LJ:::1L ~KAGEYAMA Tadashi 13 W .IE
KASE Masayuki 1.m ~ ~ Z
KUBO Toshiyuki 7... 1* fix ¥NAKAGAWA Takahide ~ }II ~ ~YOKOYAMA Ichiro ;f1( W - .M
Experimental Support Division
ICHIHARA Takashi m @. .!if
. KAN AI Yasuyuki ~ 1f: 1* Z
KUMAGAI Hidekazu 1m:a- ~ fD
MORITA Kosuke ~ EB Hi fr
WATANABE Yasushi ~ ~ ~*"*=CHIBA Yoshiaki =f ~PJJ
IKEZAWA Eiji it!!. if{
KOHARA Shigeo /J\ @. !i ~GOTO Akira f~ Di ~*1
INABE Naohito fIB ill. I'fij A
KAMIGAITO Osamu J~}~J1·f~­
KOHARA Shigeo /J' @. !i ~NAGASE Makoto -£ ~ ~OGIWARA Kiyoshi ~ @.

m

KAMBARA Tadashi 1$ @. .IE
KOBAYASHI Toshio /J\{~ it*1
MATSUZAKI Teiichiro mtlFij-t~m.e~
OKUBO Yoshitaka *7...1*~iWi
YATAGAI Fumio :a-EBJt>c~***Radioisotope Facilities Division
AMBE Fumitoshi 17::00)( fix* 1
KOBAYASHI Yoshio /J\~

IWAMOTO Masako

E

Radiation Protection Group
FUJITA Shin Di EB ~ff
NAKANISHI Noriyoshi ~ g§

NAKAJIMA Shunji~ ~ ~¥** _Secretariat. NAKAMURA Toshiko~~t*C **1t L-f-

Steering Committee
AMBE Fumitoshi 17::OO::>c fit
CHIBA Yoshiaki =f ~PJJ
HANAOKA Fumio 1E [1ijJ ::>c it
ISHIHARA Masayasu ;£ @. .IE ~KATSUMATA Koichi MJ X *tr. KOBAYASHI Toshio /J\
f~ it
MATSUOKA Masaru m [1ijJ MJ
NAG AMINE Kanetada 71< ~ ~ ,~,TAKAMI Michio rWJ Je.
1:
YAGI Eiichi i\

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YOSHIDA Tohru

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AWAYA Yohko ~ ~ ?fI. -fGOTO Akira f~ Di ~IN AMURA Takashi T. lffi ~t .!if
KAMITSUBO Hiromichi 1: P¥
KIRA Akira~~
KUMAGAI Noritaka 1m:a- ~ ~MIYAZAWA Yoshitoshi g iR.1! fix
TAKAHASHI Tan rWJ ~ 1i
TANIHATA Isao :a- ~ ~ X*3
YANO Yasushige *- ff 17: !ia*m*3 Chairperson

209

Scientific and Engineering Personnel

Cosmic Radiation Laboratory
IMAI Takashi 4'~*

KOHNO Tsuyoshi

fiiJ If~(Visitors)
HASEBE Nobuyuki ftti-tmffi1T (Fac. Gen. Educ., Ehime Univ.)llJ fr- (Fac. Eng., Kanagawa Univ.)
KASHIWAGI Toshisuke :fEI
KATO Chihiro :flo Jii =f ~ (Fac. Sci., Shinshu Univ .)il - @ (Fac. Sci., Shinshu Univ.)
MUNAKATA Kazuoki
MURAKAMI Hiroyuki fj 1: ~ ~ (Fac. ScL, Rikkyo Univ.)
NAGATA Katsuaki 7k EE Jm IlJI (Fac. Eng., Tamagawa Univ.)
NAKAMOTO Atsushi q:.
i~(Fac. Sci., Rikkyo Univ.)
YANAGIMACHI Tomoki fPn lilT M(Fac. Sci., Rikkyo Univ.)

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FUJIKI Kenichi Jii~(Fac. Sci., Ehime Univ.)
ITO Tomoyuki 1ft Jii M 1T (Fac. Sci. Eng., Waseda Univ.)
ITSUMI Norifumi ~ Jt ~ 31: (Fac. Sci. Eng., Waseda Univ.)
SHINO Tomoaki ~ ~ ~ (Fac. Sci. Eng., Waseda Univ.)
YAMAGIWA Iwao L1.J ~i ~ (Grad. Sch. Sci. Eng., Saitama Univ.)

Cyclotron Laboratory
FUJITA Jirou Iii EE.M
GOTO Akira f~ Iii ~*1
INABE Naohito
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KAGEYAMA Tadashi J~ L1J iE
KITAGAWA Hisashi ~t)ll~
KUBO Toshiyuki ~ Hk fix ¥NAGASE Makoto ft itK ~NAKAJIMA Shunji q:. ~ ~~OGIWARA Kiyoshi W( mt
SUGANUMA Hideo 'if~ X
UESAKA Tomohiro 1: #X tx i=f:
YAMAJI Shuhei L1.J ~ 11~ .If*1
YOKAYAMA Ichiro ;fl L1.J - i!~

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FUJITA Shin Iii EE fff
IKEGAMI Kumio H!Lt.:1L~ ~JIN Wei-Guo 1it t.$J 00
KAMIGAITO Osamu 1:j:g)1.fl~­
KOHARA Shigeo /J\ mt £ X
MORITA Kosuke ~ EE ~ frNAKAGAWA Takahide q:. }II q: ~NAKANISHI Noriyoshi q:. f§%
OTSUKA Takaharu±j( q: ~a*2
SUZUKI Toshio ~ft
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WAKASUGI Masanori ~ ~ {f§ 1~
YANO Yasushige Jc If ti: £*3

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ABE Yasuhisa [lliJ $ ~:A.. (Uzi Res. Cent., Yukawa Inst. Theor. Phys., Kyoto Univ.)
AKUTSU Takao ~iiJ~~~1tX (NASDA)
P] i!~ (NASDA)
AOKI Jiro W
ARAI Eiichi fff
Sit (Res. Lab. Nucl. Reactors, Tokyo Inst. Technol.)}II fO X(JAERI, Takasaki)
ARAKAWA Kazuo
BABA Shinji ,~j:~ ffi *-. (NASDA)
BATYGIN Yuri
(Elect. Phys. Dept., Moscow Eng. Phys. Inst.)
DATE Schin 1ft:ii i$ (JASRI)
DEY Ranadhir(Variable Energy Cycl. Cent.)
EJIRI Hiroyasu iI ffL~(Dept. Phys., Osaka Univ.)
EN YO Hideto ~ l:j- ~ A (Dept. Phys., Kyoto Univ.)
FUJIOKA Manabu Jii lOiJ ~ (Cyclotron Radioisot. Cent., Tohoku Univ.)
FUJISAWA Takashi Jii Vt JWJ i0 (Denki Kogyo Co. Ltd.)
FUJITA Yoshitaka Jii EE 1£ q: (Dept. Phys., Osaka Univ.)
FUJIWARA Mamoru Iii JW- ~ (RCNP, Osaka Univ.)
FUKUDA Mitsuhiro 1i EE "Yt(JAERI, Takasaki)

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210

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FUKUMOTO Sadayoshi m;
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(KEK)
FURUNO Kohei it 1ff J!.:qz. (Inst. Phys. Tandem Accel. Cent., Univ. Tsukuba)
HADA Takashi )))) EEl r;';J ~ (NASDA)
HAMA Hiroyuki m. r.t. ¥(LM.S.)HASHIMOTO Osamu m~a(Inst. Nucl. Study, Univ. Tokyo)
HATANAKA Kichiji ~ q:t 6" ~a (RCNP, Osaka Univ.)
HATSUKAWA Yuichi ;fn}ll lift (JAERI, Tokai)
HATTORI Toshiyuki ijll1f~ f3t ¥(Res. Lab. Nucl Reac., T.LT.)
HAYANO Ryugo --If!. ff Il~ 1i (Dept. Phys., Univ. Tokyo)
HEIGUCHI Kazuhiko .:qz. [] tD tit (Graduate Sch. Sci. Technol., Niigata Univ.)
HIES Markus G.
(Dept. Phys., Mainz Univ.)
HIRAO Yasuo .lJL ~ ~ ~ (N.LR.S)HIRASAWA Shokichi .:qz. iR iE 6"
HONMA Toshihiro
rj;f' ~ r.t. (Cyclotron Radioisot. Cent., Tohoku Univ.)
HORIBATA Takatoshi t)ffi!Iffii q: f3t (Fac. Eng., Aomori Univ.)
HORIGUCHI Takayoshi :lJ£ [] ~.i ~ (Dept. Phys., Hiroshima Univ.)
HORIUCHI Hisashi :lJ£ pg jJ(8 (Dept. Phys., Kyoto Univ.)
HOSONO Kazuhiko *m ff fD ffi (RCNP, Osaka Univ.)
IGARASHI Toshio 1i jJifliiiift (NASDA)
IKEDA Kiyomi Hi? EEl m- ~ (Dept. Phys., Niigata Univ.)
IKEDA Nobuo i-lli. EEl i$ X (Inst. Nucl. Study, Univ. Tokyo)
IKEGAMI Hidetsugu i-lli. 1: 5R mL (RCNP, Osaka Univ.)
IKEZOE Hiroshi i-lli. ~ t-W (JAERI , Tokai)
IMAI Kenichi A,
1f!. (Dept. Phys., Kyoto Univ.)
i': lift (Inst. Nucl. Study, Univ. Tokyo)
IMAMURA Mineo A,
INOUE Makoto
1:(Inst. Chern. Res., Kyoto Univ.)
ISHII Takayuki ;fiq: ¥ (N ASDA)
ISHIZUKA Takeo ;fi ±j( JE\ ~ (Dept. Phys., Saitama Univ.)eg (JAERI, Tokai)
IWAMOTO Akira E
IWASHITA Yoshihisa E ~ =Jj !A. (Inst. Chern. Res., Kyoto Univ.)
IZUMOTO Toshiaki JR
flJ(ColI. Sci., Rikkyo Univ.)
JEONG S. C.
(Inst. Nucl. Study, Univ. Tokyo)
KAJI Harumi i~ {ElHi¥ (Dept. Phys., Tohoku Univ.)
KAMEYAMA Hirofumi .. t1J ~15-)( (Dept. Phys. , Chiba Keizai Jr. ColI.)
KAMIMURA Masayasu 1:
iE fflt (Dept. Phys., Kyushu Univ.)
KANAZAWA Mitsutaka 1fi: if{ 1t~.i (N.LR.S.)
KANMURI Tetsuo ]@; ~ X (Dept. Phys., Osaka Univ.)
KANNO Tooru "if ff 1ft{ (NASDA).KATSURAGAWA Hidetsugu tt}ll ~ rlUPJ (Dept. Phys., Toho Univ.)
KATAYAMA Ichiro h t1J -.M (Inst. Nucl. Study, Univ. Tokyo)
KATAYAMA Takeshi h t1J JE\ PJ (Inst. Nucl. Study, Univ. Tokyo)
KATO Kiyoshi 11D Jii ~ =Jj (Dept. Phys., Hokkaido Univ.)
KATORI Kenji !'F.:Itt ~(Dept. Phys., Osaka Univ.)
KATOU Shouhei 110 Jii l§.:qz. (Dept. Phys., Osaka Univ.)
KAWAGUCHI Takeo )11 [] JE\ ~ (Mitsubishi Electric Co., Ltd.)KAWAGUCHI Hideo )1/ [] ~ X (Tokyo Denshi Co., Ltd.)KAWAI Mitsuji filJ 1} 1t ~ (Dept. Phys., Kyushu Univ.)
KIKUCHI Fumio §iij i-lli. )( ~ (ColI. Arts Sci., Univ. Tokyo)
KONDO Michiya :iJ.i Jii :i1! -t!! (RCNP, Osaka Univ.)
KOSAKO Toshiso /J\1tr.itflii;:f± (Atomic Energy Res. Cent., Univ. Tokyo)
KOTAJIMA Hisaya it EEl .§:b!A.J5J(; (Fac. Eng., Tohoku Univ.)
KOUMOTO Toshirou iPJ
flii i!~ (Dept. Phys., Kyoto Univ.)
KUBOYAMA Satoshi !A.i:*t1J~PJ (NASDA)
KUDO Hisaaki I Jii !A. eg (Dept. Chern., Niigata Univ.)
KUROYANAGI Tokihiro ~;wn~** (Dept. Phys., Kyushu Univ.)
LEE Kong Ok
fflt.:E (Rika Women's ColI.)
LEE Sang Mu;f§:a (Dept. Phys., Univ. Tsukuba)
LIN Ching-Liangm- iff- (Taiwan Univ.)

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MAEDA Kazuhide fiij E8 fD ~ (Dept. Phys., Kyushu Univ.)
MARUMORI Toshio :n ~ ~(Fac. Sci. Technol. , Sci. Univ. Tokyo)
MATSUDA Sumio ~ IE f.iH
(NASDA)
7i -f- (Fac. Technol. , Tokyo Univ. Agr. Technol.)
MATSUI Yoshiko ~MATSUKI Seishi ~fiE ~ (Inst. Chem. Res., Kyoto Univ .)MATSUSE Takehiro ~ iii ?t a3- (Dept. Phys. , Shinshu Univ.)
MATSUYANAGI Kenichi ~ fPn ;pJf ~ (Dept. Phys., Kyoto Univ.)
MIAKE Yasuo
I3JJ ~.M (Inst. Phys. , Univ. Tsukuba)
MIDORIKAWA Shoichi ~~ )I[ • ~ (Fac. Eng. , Aomori Univ.)
MINAMISONO Tadanori i¥i III it, J!IJ (Dept. Phys. , Osaka Univ.)
MITSUMOTO Toshinori it:
1~ ~(Sumitomo Heavy Industries , Ltd.)ilfl" :E- (RCNP, Osaka Univ.)
MIURA Iwao
MIYAMURA Osamu g *1 1~ (Fac. ScL, Osaka Univ.)
MIYATAKE Hiroari g JEt ~ -m (Fac. Sci., Osaka Univ.)
MIZOTA Takeshi ~ IE JEt ~ (Inst. Phys., Univ. Tsukuba)(RCNP, Osaka Univ.)
MIZUNO Yoshiyuki 7j(!ff. Z
MORI Yoshiharu ~ •(KEK)
MURAKAMI Tetsuya *1 1: tg' -m (Dept. Phys. , Kyoto Univ.)
MURAYAMA Toshiyuki *1' LlJ flJ ¥(Tokyo Univ. Mercantile Marine)
MUROTANI Shin :£::§. it) (Sch. Sci. Eng., Waseda Univ.)
NAGAI Yasuki 7k~ tit(Dept. Appl. Phys., Tokyo Inst. Technol.)(NASDA)NAITOU Ichiro IAJ iii ~ 1!B
NAKAHARA Hiromichi r:prJL if! (Dept. Chem., Tokyo Metrop. Univ.)
NAKAI Koji r:pr8(KEK)
5b J{ A (NASDA)
NAKAJIMA Masato
NAKAMURA Ichiro*1' m1!B (Dept. Phys. , Saitama Univ.)
NAKAMURA Masao*1' iE(N ASDA)NAKAMURA Takashi r:p *1' ~ P] (Cyclotron Radioisot. Cent. , Tohoku Univ.)
NEMOTO Norio tH~(NASDA)NIIMURA Masanobu fJf *1' iE 18 (Sch. Sci. Eng. , Waseda Univ.)
NIITA Koji t*IEH1i'= (JAERI, Tokai)(Inst. Chem. Res ., Kyoto Univ.)
NODA Akira ff IE •NODA Kouji ff IE *If: P] (N.I.R.S.)NOMURA Toru ff *1' 7- (Inst. Nucl. Study, Univ. Tokyo)
OGATA Hiroshi /J~ 11 J[ (RCNP, Osaka Univ.)
OGAWA Kengo /J\)I[ 11 ~ (Fac. Educ. , Chiba Univ.)
OKABE Shigetou [M] $ f&. ~ (Cent. Inf. Proc. Educ. , Hokkaido Univ.)
OKAMURA Hiroyuki [M] *1 rJL Z (Dept. Phys. , Univ. Tokyo)
OKUMURA Susumu ~ *1' :ii (J AERI, Takasaki)
ONISHI Naokig§ ill f1 (ColI. Arts Sci., Univ. Tokyo)
OOHIRA Hideharu
f ~ ~ (NASDA)
OOTSUKI Tsutomu~f}J (Lab. Nucl. Sci., Tohoku Univ.)ag(NASDA)OOURA Akio
1!B (N ASDA)OOYA Jirou
OSUGA Toshiaki ,*~~~fitI3JJ (ColI. Arts Sci. , Chiba Univ.)
PU Yuehu ri t!! J1E (Inst. Nucl. Study, Univ. Tokyo)
QUAN Zhuo-Shu ~ !j! fit (Dept. Phys. , Hosei Univ.)
ROA Yi Nong
(Inst. Modern Phys. , Academia Sinica, China)
SAGARA Kenji t§ ~ lit ~ (Dept. Phys., Kyushu Univ.)
1T (Dept. Phys. , Univ. Tokyo)
SAKAI Hideyuki i! 1f
SASAG AWA Tatsuya itt) I[ J.lR ~fJ\ (CoIl. Eng., Nihon U niv.)(N .I.R.S.)
SATO Yukio 1tL iii ¥SATOU Kenichi 11:: iii ~ ~ (Dept. Phys. , Tohoku ColI. Pharm.)
SATOU Kenji 11:: iii 11(N.I.R.S.)
SEBE Takashi$
q: (Dept. Phys., Hosei Univ.)
SEKINE Toshiaki /MJ tH 1~ I3JJ (J AERI, Tokai)
SHIBATA Tokushi ~ E8 1:E. I~' (Inst. Nucl. Study, Univ. Tokyo)
III Ll ~ (JAERI, Tokai)
SHIKAZONO Naoki

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SHIMANO Yosuke (/J.~ If ~$ 11' (NASDA)
SHIMIZU Akira Wi 71< Bg (RCNP, Osaka U niv.)
SHIMOMURA Koichiro T:1'1~-fI~ (Meson Sci. Lab., KEK Brunch, Univ. Tokyo)
SHIN Kazuo ~ ~ X (Fac. Eng., Kyoto Univ.)
SHIN Seung Ai~ (Rika Women's ColI.)
SHINOZUKA Tsutomu ~ ±j( ~ (Cyclotron Radioisot. Cent., Tohoku Univ.)
SHIRAI Toshiyuki B 1t fiX Z (Res. Inst. Fund. Phys., Kyoto Univ.)
SUEKI Keisuke~ it(Dept. Chern., Tokyo Metrop. Univ.)
SUGAIIsao "if 1t JI!k (Inst. Nucl. Study, Univ. Tokyo)
SUGIYAMA Hiroki ~ LiJ
It (NASDA)
SUMIYOSHI Hiroyuki 1£
J1;. 1T (Matsusho-Gakuen Jr. Coli.)
fi:t ~ (Dept. Phys., Fukui Univ.)
SUZUKI Toshio ~~SUZUKI Toshio ~~13t X (Dept. Phys., Nihon Univ.)
TAGISHI Yoshihiro EE j$ *i(Tandem Accel. Cent., Univ. Tsukuba)
TAJIMA Naoki EE (/J.~ ti It (ColI. Arts Sci., Univ. Tokyo)
TAKADA Kenjiro rmEE1~Vj(fI~ (Dept. Phys., Kyushu Univ.)
TAKEMASA Tadashi ff:t jJ)c ~ ± (Kyoto Univ. Educ.)
TAKEUCHI Suehiro it pq
J1;. (JAERI, Tokai)
TAKIGAWA Noboru it)1I Jf- (Dept. Phys., Tohoku Univ.)
TAMAGAKI Ryozou ~ J:J[ .E!
(Dept. Phys., Kyoto Univ.)
TAMURA Takashi EE:1'1 rm ~ (NASDA)
TANABE Kazuko EH ill. ~ -f- (Otsuma Women's ColI.)
TANAKA Jinichi EH q:r t m (Inst. Nucl. Study, Univ. Tokyo)
TANAKA Kazuhiro EE q:r ~D" (Dept. Phys., Hiroshima Univ.)
TANAKA Yasushi EE q:r 1* ~ (Kyokuto Boeki Kaisha, Ltd.)TANIKAWA Masashi ~)II J]J ~ (Dept. Chern., Univ. Tokyo)
TOHYAMA Mitsuru :iI LiJ ~iMJ (Kyorin Univ.)
TOMIMASU Takio 'g~ $%X (FEL Res. Inst. Inc.)TOMITANI Takehiro 'g ~ ff:t ~ (N.I.R.S.)TOMOTA Toshiaki 1X EE fi:t. (Fac. Eng., Aomori Univ.)
TORIYAMA Tamotsu ,~LiJ 1* (Dept. Phys., Musashi Inst. Technol.)
TSUNEMOTO Hiroshi ,t!i 5t tw: (N.I.R.S.)
UESUGI Masato 1: ~ iE A (NASDA)UTSUNOMIYA Hiroaki f:lf~g~. (Fac. Sci., Konan Univ.)
UWAMINO Yoshitomo 1:. *i 1m (Inst. Nucl. Study, Univ. Tokyo)
WADA Michiharu ~D EE j]!
(Inst. Nucl. Study, Univ. Tokyo)
WADA Takahiro ~ EE ~(Osaka Dental CoH.)
WAKAI Masamichi ;g: 1t iE it (Dept. Phys., Osaka Univ.),WAKUTA Yoshihisa fD~EH*i~ (Fac. Eng., Kyushu Univ.)
WANG Zhei.:£.. (Inst. Modern Phys., Acad. Sinica)
XIA Jiawen :I {!::>c (Inst. Modern Phys., Acad. Sinica)
YAMADA Taiichi LiJ EH ~ (ColI. Eng., Kanto Gakuin Univ.)
ti: X (Tsuru Univ.)
YAMAMOTO Yasuo LiJ
YAMANOUCHI Mikio LiJ pq *!it (Tandem Accel. Cent., Univ. Tsukuba)
YAMAZAKI Hirohito LiJ ~ )t t
(Lab. Nucl. Sci., Tohoku Univ.)
YAMAZAKI Takashi LiJ ~ ft (RCNP, Osaka Univ.)
YOSHIDA Noriaki
EH(Fac. Eng., Kansai Univ.)
YOSHIDA Shiro
EH ,Ff!!, fI~ (Dept. Phys., Ishinomaki Senshu Univ.)
YOSHINAGA Naotaka
71< ~.q: (Dept. Phys., Saitama Univ.)/MJ 1ft ~ (NASDA)YOSHIOKA Yasuhiro
YOSHIZAWA Yasukazu a if{ 1ft ~ (Fac. Eng., Kyushu Univ.)
YUAN You-Jin(Inst. Modern Phys., Acad. Sinica, China)
ZHANG Li 5&
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AKAZAWA Takashi iffi ~*(Dept. Phys., Saitama Univ.)
AOKI Yuka W
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ARIGA Takehiro :ff ~ 1l1f (Dept. Phys., Saitama Univ.)*213

FURUYA Shinji E:fr {§ WJ (Dept. Phys., Tokyo Inst. Technol.)
FUTAMI Yasuyuki
Jt rnt Z. (Dept. Phys., Univ. Tsukuba)
HAMADA Shingo ~ ill A '/-g. (Inst. Chern. Res., Kyoto Univ.)
HIRAI Masahide -¥ 1f~(Dept. Phys., Sophia Univ.)
HONJYOU Yoshio
it X (Dept. Phys., Univ. Tsukuba)
HONMA Hiroyuki(Dept. Appl. Phys., Tokyo Inst. Technol.)
INOUE Jirou 1f J:::.
1!B (Dept. Phys., Sophia Univ.)
ITAGAKI Shouhei ;f,OC ig ~ -¥ (Dept. Phys., Saitama Univ.)
KANGYO Yoshitsugu a iT ~ RRPJ (ColI. Sci., Chuo Univ.)
KASHIWABARA Taketo ;ftl ijji 1!l A (Dept. Phys., Toho Univ.)
KIM Eun Ju(Dept. Phys., Tohoku Univ.)
KUMAGAI Kenji n~:fr 1!l(Dept. Phys. , Hiroshima Univ.)
KURIHARA Kaori ~ 1* W (Dept. Phys., Univ. Tsukuba)
KURITA Tetsuro ~ ill ~ 1!B (Dept. Phys., Univ. Tsukuba)
KUROSAWA Tadahiro ~ iR ,r~, 5.L (Dept. Phys., Tohoku Univ.)
Z. (Fac. Sci., Konan Univ.)
MABUCHI Hideyuki .~ ml
MARUYAMA Toshiki JL W fit.~!i (Dept. Phys., Kyoto Univ.)
MATSUMOTO Norihiro ~~ i$(Fac. Sci., Kounan Univ.)
MINEMURA Toshiyuki ~ if1 {~1T (ColI. Sci., Chuo Univ.)
MIURA Takashi ~ iii(Dept. Phys., Univ. Tsukuba)
NAKAGAWA Keiko 4' )11 ~ -f- (Dept. Phys., Tohoku Univ.)
NAKAO Noriaki 4' If:. tl@ 11'1 (Cyclotron Radioisot. Cent., Tohoku Univ.)
NISHIMORI Nobuyuki I!§ ~ {§ iT (Dept. Phys., Kyushu Univ.)ODA Ayato *l ill ~ A (Tokyo Univ. Mercantile Marine)
OGAWA Izumi /J\)II ~ (Int. Chern. Res., Kyoto Univ.)
OOSAKI Toshiro~ fit. 1!B(Dept. Appl. Phys., Tokyo Inst. Technol.)
OZAWA Shuiti /J\ ~ {I~ (ColI. Sci., Rikkyo Univ.)RYU Shin(Dept. Phys., Univ. Tsukuba)
SASAKI Reiji f~/.{*~t (Dept. Phys., Tohoku Univ.)-f- (Dept. Phys., Univ. Tsukuba)
SATOU Eiko f~ iii
SEINO Satoshi
ff 1[;& (Dept. Appl. Phys., Tokyo Inst. Technol.)(Dept. Appl. Phys., Tokyo Inst. Technol.)
SENO Kenichi ~ If:. It SHINOZAKI Akihisa 1ll ~ .!A.. (Dept. Phys., Tohoku Univ.)
TAGAYA Yu $iJO:fr :f1i (Dept. Phys., Univ. Tokyo)
TAKADA Masashi ~ ill A i0 (Cyclotron Radioisot. Cent., Tohoku Univ:)
TAKAHASHI Takumi r.:b
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(ColI. Sci., Chuo Univ.)
TAKEDA Kenji it ill It i0 (Dept. Appl. Phys., Tokyo Inst. Technol.)
TOMITA Shigeo ~ ill JJX. X (Dept. Phys., Univ. Tsukuba)
TOMOHISA Yasuhiko 1§..!A.. H~ /$ (Dept. Phys., Univ. Tsukuba)
UMETSU Youitiro ffft~*~~-1!B (Dept. Phys., Tohoku Univ.)UTIYAMA Kouji IAJ tlJ ?ii i0 (Dept. Phys., Saitama Univ.)
i0 (Dept. Phys., Toho Univ.)WAKUI Takashi i~ 1f
WATANABE Koutarou ilt~rnt*1!B (Dept. Appl. Phys. , Tokyo Inst. Technol.)
YAMAGAMI Munetaka W J:::.
~(Fac. Sci., Konan Univ.)
YAMASHITA Ayako tlJT~~-f- (Dept. Phys., Toho Univ.)
YORITA Tetsuhiko ~ ill ~ /$ (Dept. Phys., Tohoku Univ.)
YUKI Hideyuki *5 ~ ~ iT (Dept. Phys., Tohoku Univ.)=a* not' m z.

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CHIBA Toshiya =f ~ flJ t&
FU JIMAKI Masaki iii ~ iE
HEMMI Masatake ~ ~ iIX ff:t
IKEZAWA Eiji HI! iR
KOBAYASHI Toshio /J\{~ tl*MIYAZAWA Yoshitoshi g iR {t fit.
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CHIBA Yoshiaki =f ~ iff fiJI
FUKUDA Moichi 1i ill L€ HIRENZAKI Satoru It:it~ 't~
KASE Masayuki 110 ift l§ Z.
KUMAGAI Hidekazu n~:fr ~ fD
MOMOTA Sadao Efillf~$1:
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TANIHATA Isao :§.:J:m ~ x**
YANOKURA Minoru ~ff~ ~* Senior Scientist,TONUMA Tadao
YOSHIDA Koichi** Chief Scientist(Visitors)
ALEKSANDROV D. V.
(Kurchatov Inst., Russia)
ARATANI Michi )it:& ~ ~ (Inst. Enviromental Sci.)
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, Brazil)
CARLSON Brett
CHLOUPEK Frank(Ohio State Univ., U.S.A.)(Kurchatov Inst. Atomic Energy, Russia)
DEMYAN OVA AlIa S.
FENG Jun i.~11[ (Shanghai Inst. Nucl. Res., China)
FUJIWARA Mamoru ni ffit ~ (RCNP, Osaka Univ.)(Fac. Sci., Sci. Univ. Tokyo)
FURUYA Keiichi t:!l:§. I HIRATA Daisy(CTA, Inst. Estudos Avancados, Brazil)
ITO Noriaki f-Jt ni jf. ag (Dept. Cryst. Mater., Nagoya Univ.)
KAlMAN Varga* (Atomki, Debrecen, Hungary)
KANAZAWA Kenichi -it ~~ 1@ (KEK)
KATORI Kenji g[~(Fac. Sci., Osaka Univ.)
KIKUCHI Jun *J i-tt!. JIIJi (Sci. Eng. Res. Lab., Waseda Univ.)
KIMURA Kikuo =*tt%)...ii (Fac. Eng., Nagasaki Inst. Appl. Sci.)
KOLATA James(Notre Dame Univ., U.S.A.)(Kurchatov Inst., Russia)
KORSHENINNIKOV A. A.
MATSUTA Kensaku ~ $1@(Fac. Sci., Osaka Univ.)
MATUOKA Nobuyuki ~ [tn] 1$ iT (Res. Cent. Nucl. Phys., Osaka Univ.)
MOCHIZUKI Keiko ~Ji I-1- (Fac. Sci., Osaka Univ.)
MOON Chang-Bun(Seoul Natl. Univ., Korea)
MURAOKA Mitsuo tt [tn] J't ~ (ColI. Arts Sci., Chiba Univ.)
NIKOLSKI Evgenini Y.
(Kurchatov Inst., Russia)
NOJIRI Yoichi ff ffL ~:F (Fac. Sci., Osaka Univ.)(ColI. Arts Sci., Chiba Univ.)
OGAWA Kengo /J . . JII(Kurchatov Inst. , Russia)
OGLOBLIN Alexei A.
OJIMA Minoru /J . . ~~ ~ (Fac. Sci., Osaka Univ.)
OMATA Kazuo /J . . i~ fD X (Inst. Nucl. Study, Univ. Tokyo)(Ohio State Univ., U.S.A.)RAIMANN Gerhard.SAGAWA Hiroyuki f~)II 51. ¥(Fac. ScL, Univ. Tokyo)~ iT(Fac. Sci. , U niv. Tokyo)
SAKAI Hideyuki iili
SATO Kazuhiro f~ ni fD r.t. (Tokyo Fire Dept.)
SUDA Toshimi ~j B3 *11 ~ (Fac. Sci., Tohoku Univ.)
SUGAWARA Masahiko '! ffit ~"ffi (Fundam. Sci., Chiba Inst. Technol.)SUZUKI Yasuyuki jit =* '§ Z (Fac. Sci. Niigata Univ.)
TOKI Hiroshi ± iI!i tf (Fac. Sci., Tokyo Metrop. Univ.)
WADA Takahiro fD E8 ~(Osaka Dentist Univ.)
YAMAGUCHI Hiromi LiJ IJ m ~ (Sci. Eng. Res. Lab., Waseda Univ.)ZAHAR Mohamed(Dept. Phys., Notre Dame Univ., U.S.A.)

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HARADA Akihiko ffit E8 ag ~ (Fac. Sci., Osaka Univ.)
IZUMIKAWA Takuji jJ{)II!$i PJ (Fac. Sci., Osaka Univ.)(Fac. Sci., Sci. Univ. Tokyo)
MATSUSHITA Kenichi ~ ~ 1@ MIHARA Mototsugu := ffit ~ rlUPJ (Fac. Sci., Osaka Univ.)
MIYAKE Toru ~ ~ 11& (Fac. Sci., Osaka Univ.)
MIYAMOTO Shinya gJ{. ~ (Fac. Sci., Tokyo Metrop. Univ.)*215

NAKAZATO Masahisa 9=' Jt A 7-. (Fac. Sci., Osaka Univ.)[§(Fac. Sci., Osaka Univ.)
ONISHI Takashi
SASAKI Makoto {ti:~* WiX (Fac. Sci., Osaka Univ.)
TANIGAKI Minoru :fr:J:g ~ (Fac. Sci., Osaka Univ.)
YAMAGUCHI Takayuki tlJ IJ .. Z (Fac. Sci., Osaka Univ.)*"*

Radiation Laboratory
FUKUNISHI Nobuhisa W; [§ ~ MJ
ISHIHARA Masayasu il mt iE ~*KISHIDA Takashi i¥ EB ~NAKAMURA Takashi 9=' iff ~ Ii)
TAKAHASHI Tan r.Q ~ 11
WATANABE Yasushi iJi ~ mt

ICHIHARA Takashi m mt !j!
IZUM 0 Koichi tI1 ~ J't KONNO Satoshi ~ If ~OKUNO Hiroki ~ If ]A tit
TEND OW Yoshihiko X
7i ~YOSHIDA Atsushi IS rn *~m* Chief Scientist(Visitors)
ABE Yasuhisa IfIIJ:gB ~ (A (Yukawa Inst. for Theor. Phys., Kyoto Univ.)
ADACHI Minoru JE Jr •(Fac. Sci., Tokyo Inst. Technol.)
ANDO Yoshiaki tr: Di(ColI. Sci., Rikkyo Univ.)
ARTUKH Anatoly(Flerov Lab. Nucl. Reactions, Joint Inst. Nucl. Res., Dubna, Russia)
ASAHI Koichiro it!!. *it-.M (Fac. Sci., Tokyo Inst. Technol.)
BECK F. A.
(Groupe RSN, Strasbourg, France)
BROGLIA R.
(Univ. Milano & INFN, Italy)
CASTEN Rick(Phys. Dept., Brookhaven Nat. Lab., USA)
DELBAR Thierry(Univ. Catholique de Louvain, Belgium)
DOKE Tadayoshi,~, fi(Sci. Eng. Res. Lab., Waseda Univ.)
ENYO Hideto ~ l:j- ~ A (Fac. ScL, Kyoto Univ.)
FLO CARD Hubert(Div. Phys. Theor., Inst. Phys. Nucl., Orsay, France)
FRANCE Ralf (Yale Univ., USA)FUCHI Yoshihide mrJ !if ~ (Inst. Nucl. Study, Univ. Tokyo)
FUJIOKA Manabu »i IMJ ~ (Cyclotron and Radioisot. Cent., Tohoku Univ.)
FUKUDA Tomokazu
E8 ~ f[] (Inst. Nucl. Study, Univ. Tokyo)
FUKUDA Mitsunori W; E8 J't}!lJi (Fac. Sci., Osaka Univ.)
GAl Moshe(Yale Univ., USA)GONO Yasuyuki ~ Il ~ Z (Fac. Sci., Kyushu Univ.)(California Inst. Technol.)
HAHN Kevin I.
HASEGAWA Takeo ~:fr)II:fEt~ (Fac. Eng., Miyazaki Univ.)
HOSAKA Masahito 1*:IJj *~ A (Inst. Nucl. Study, Univ. Tokyo)
ICHIMURA Munetake m iff~(ColI. Arts and Sci., Univ. Tokyo)
IEKI Kazuo~ f[] X(ColI. Sci., Rikkyo Univ.)
IMAI Kenichi A,
J! (Fac. Sci., Kyoto Univ.)
ISHIDA Nobumichi il rn 1$ m (Seikei Univ.)
KASAGI Jirota !i*ta.M* (Lab. Nucl. Sci., Tohoku Univ.)
KATAYAMA Ichiro h tlJ -.M (Inst. Nucl. Study, Univ. Tokyo). KATO Seigo :1.10 Di m- ~ (Fac. Ed., Yamagata Univ.)(Fac. Sci., Osaka Univ.)
KATORI Kenji !'E 1& ~~(Inst. Nucl. Study, Univ. Tokyo)
KAWAKAMI Hirokane )11 1:
KAWASHIMA Hideo )11 §'b ~ ii (Inst. Nucl. Study, Univ. Tokyo)
KIKUCHI Jun *J i-I:!? JIIJi (Sci. Eng. Res. Lab., Waseda Univ.)(Dept. Phys., Seoul Natl. Univ., Korea)
KIM Jong Chan
KITAO Kensuke ~ $~ J!lIJJ (Data Eng. Inc.)KUBONO Shigeru 7-.f*If It (Inst. Nucl. Study, Univ. Tokyo)
KUBOTA Shinzo ~ E8 ffi ~ (ColI. Sci., Rikkyo Univ.)
KUSAKARI Hideshige 1fi XIJ ~ ~ (Fac. Ed., Chiba Univ.)
LEE Sang Mu
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LIPNIK Peter(Univ. Catholique de Louvain, Belgium)

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MAEDA Kazushige M E8 ~(CoIl. Gen. Ed., Tohoku Univ.)
MASUDA Kimiaki ~ E8 ~ PJJ (Saitama ColI. Health)
MATSUYANAGI KenichitDP Wf (Fac. Sci., Kyoto Univ.)
MENGONI Alberto(ENEA, Ente Nazionale, Italy)
MICHOTTE Carine(Univ. Catholique de Louvain, Belgium)
MIN Byung-Joo I¥J ~ ~ (Korea Atomic Energy Res. Inst., Korea)
MITARAI Shiro ~fHt~.M (Fac. Sci., Kyushu Univ.)
MIYACHI Takashi g:ttB q: (Inst. Nucl. Study, Univ. Tokyo)
MIYATAKE Hiroari g:iE.\ f: -I:!! (CoIl. Gen. Ed., Osaka Univ.)
MORIKAWA Tsuneyasu ~)II 'I:!i fi: (JAERI)
MORINOBU Shunpei ~ {§ 13t J:f (Fac. Sci., Kyushu Univ.)~*~(CoIl. Sci., Rikkyo Univ.)
MOTOBAYASHI Toru
MOTTELSON Ben R.
(NORDITA, Copenhagen, Denmark)
MUELLER Ludwig(Univ. Padova, Italy)
MURAKAMI Takeshi ft 1: ~ (Natl. Inst. Radiol. Sci.)
NAGAI Yasuki 7"7< 1f ~ W (Fac. Sci., Tokyo Inst. Technol.)NAGASHIMA Yasuo~ ~ ~(Inst. Phys., Univ. Tsukuba)
NAKAJIMA Mitsuo ~ ~ 7E ~ (Grad. Sch. Nagatsuta, Tokyo Inst. Technol.)
NAKAMURA Shogo ~ fj iE ~ (Fac. Ed., Yokohama Natl. Univ.)
NAKAYAMA Shintaro ~ w{§*1!B (Coll. Gen. Ed., Tokushima Univ.)
NIIZEKI Takashi '*JT ~ ~i (Fac. Sci., Tokyo Inst. Technol.)
NORO Tetsuo ff g rg ~ (Res. Center Nucl. Phys., Osaka Univ.)
OGAWA Masao /J~ )11 ff 1:: (Graduate Sch. Nagatsuta, Tokyo Inst. Technol.)
OKAMURA Hiroyuki lOCi] fj iJL. Z (Fac. Sci., Univ. Tokyo)m m (Fac. Sci., Tokyo Inst. Technol.)
ONUMA Hajime
ORIHARA Hikonojyo *'imt~Z:1s (Cyclotron and Radioisot. Cent., Tohoku Univ.)~ J{ lit(JAERI)OSHIMA Masumi
OTSUKA Takaharu
q: tEl (Fac. Sci., Univ. Tokyo)
OYAIZU Michihiro /J~f!iP~f7EJA (Inst. Nucl. Study, Univ. Tokyo)
PENIONZHKEVICH Yuri
(Flerov Lab. Nucl. Reactions, Joint Inst. Nucl. Res., Dubna, Russia)
PETER Jean Jean Peter(Caen Univ., France)
RUAN (GEN) Jian-Zhi ~jG ~ 1El (ColI. ScL, Rikkyo Univ.)
SAGAWA Hiroyuki 1t.)11 iJL. ¥(Cent. Math. ScL, Univ. Aizu)
SAKAGUCHI Harutaka :I:Ji IJ 1El ~ (Fac. Sci., Kyoto Univ.)
SAKAI Mitsuo :I:Ji 1f -1t ~ (Inst. Nucl. Study, Univ. Tokyo)
SAKURAGI Hiroyuki ff
iJL. Z (Fac. Sci., Osaka City Univ.)
SAKURAI Hiroyoshi ff 1f tf fi (Fac. Sci., Univ. Tokyo).SATO Hiroshi it. Jii ~1Z (Seikei Univ.)
SCARLASSARA Fernando(Univ. Padova, Italy)
SCHMIDT-OTT Wolf-Dieter(II Physicalisches Inst. Univ., Gottingen, Germany)
SHIBAMURA Eido ~ fj
(Saitama ColI. Health)
SHIBATA Toshiaki ~ E8 flJ PJJ (Fac. ScL, Tokyo Inst. Technol.)
SHIMIZU Yoshifumi
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SHIMIZU Hajime tw 7]( ~ (Fac. Ed. Yamagata Univ.)
SHIMODA Tadashi r E8 iE (ColI. Gen. Ed., Osaka Univ.)
SHIMOURA Susumu~(CoIl. Sci. , Rikkyo Univ.)
SHIRATO Shoji B ± if}(CoIl. ScL, Rikkyo Univ.)
SIGNORINI Cosimo(Phys. Dept., Inst. Nazionale di Fisica Nucl., Italy)
SUGAWARA Masahiko 'I mt ~ ~ (Chiba Inst. Technol.)~ tit(Japan Synchrotron Radiat. Res. Inst.)
SUZUKI Masayo i{t1L Z (Fac. Sci., Niigata Univ.)
SUZUKI Yasuyuki i{t(Natl. Inst. Radiol. Sci.)
TAKADA Eiichi ~ E8 %: (Fac. Sci., Univ. Tokyo)
TAKAHASHI Tadayuki r.b fl ,i:, ¥TAKAHASHI Noriaki r.b flYM. PJJ (CoIl. Gen. Ed., Osaka Univ.)
TAKAKU Seisaku r.b 7... tw i'l= (Inst. Nucl. Study, Univ. Tokyo)
TAKIGAWA Noboru ?1@;)II ~ (Fac. Sci., Tohoku Univ.)
TANAKA Masahiko E8 ~ ff ~ (Inst. Nucl. Study, Univ. Tokyo)

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TAN OKURA Atsushi ill!f~(Fac. Sci. Technol., Sophia Univ.)
TERAKAWA Atsuki '=!f ll[ .. mt (Cyclotron and Radioisot. Cent., Tohoku Univ.)
TOKI Hiroshi ± wi t!'J: (Res. Cent. Nucl. Phys., Osaka Univ.)
TOYOKAWA Hidenori ~ ll[ ~ wI[ (Res. Cent. Nucl. Phys., Osaka Univ.)(Ministry of Education, Sci. Culture)
UNO Masahiro ~!f iE:f1i ~ (Fac. Sci. Technol., Sophia Univ.)
YAMAMOTO Sukeyasu L1J
YAMAYA Takashi L1J ~ ~ (Fac. Sci., Tohoku Univ.)
YOSHINAGA Naotaka Ef 71< MJ q: (ColI. Lib. Arts, Saitama Univ.)YOSOI Masaru ~~1=t fI (Fac. Sci., Kyoto Univ.)**(Students)
AOI Nori W 1t ::1J (Fac. Sci., Univ. Tokyo)
CHAE Soo Joh ~ i*:r:t (Dept. Phys., Seoul Natl. Univ., Korea)
DOl Masashi ± 1t ~ ~ (Fac. Sci., Tokyo Inst. Technol.)
DOKI Yasuhiro ± ~c. fflt t!f (Fac. Sci., Univ. Tokyo)
FUJITA Tetsushi iii ill rg- ~ (Fac. Sci., Univ. Tokyo)~ Wi(Fac. Sci., Tokyo Inst. Technol.)
HANAKI Hidenobu 1E
HASUIKE Katsuhito ~MJ A (Sci. Eng. Res. Lab., Waseda Univ.)
HARA Yosuke rnt ~$ 1r (Fac. Sci., Tokyo Inst. Technol.)
HARADA Masaki rnt ill ~ W (Fac. Sci., Tokyo Inst. Technol.)
HIRAI Masaaki ~ 1=t iE I3JJ (Fac. Sci., Univ. Tokyo)
HORI Yoichi t)ffi ~~ (Fac. Sci., Tokyo Inst. Technol.)
HORI Masaki ;t)ffi iE 1M (Pac. Sci., Univ. Tokyo)
HORI Junichi ;t)ffi
JIIji (ColI. Sci., Rikkyo Univ.)
HOSOMICHI Kazuo *IB if! fD X (Pac. Sci., Univ. Tokyo)
ICHIGE Masayuki~ iE L(Sci. Eng. Res. Lab., Waseda Univ.)
IDEGUCHI Eiji 1=tf-IJ5R?S (Fac. Sci., Kyushu Univ.)
IKEDA Yasufumi ag ill(ColI. Sci., Rikkyo Univ.)
INOUE Masahiro 1t 1:: If§(ColI. Sci., Rikkyo Univ.)
ISHIDA Satoru :£ ill t~ (Fac. Sci., Univ. Tokyo)
ITO Mikihiko 1¥ iii ~ ~ (Fac. Sci., Tokyo Inst. Technol.)
ITO Tomoyuki #f iii M 1-r (Sci. Eng. Res. Lab., Waseda Univ.)
W (ColI. Sci., Rikkyo Univ.)
IWAMOTO Susumu !6
IWASA Naohito !6 {1£ ut 1= (ColI. Sci., Rikkyo Univ.)
IWATA Yoshiyuki !6 ill 1* L
(ColI. Sci., Rikkyo Univ.)
IZUMI Hideaki ill 7]( ~ I3JI (Pac. Sci., Tokyo Inst. Technol.)
KAMIMURA Kazuto 1:: 1'1 fD A (ColI. Sci., Rikkyo U niv. )KANEDA Naoya 1t ill ili 1:11 (Fac. Sci., Kyushu Univ.)
KATO Kenichi 1.10 iii. (Fac. Sci., Tokyo Inst. Technol.)
KATO Toshiyuki 1.10 iii {~¥ (Sci. Eng. Res. Lab., Waseda Univ.)
KAWAGUCHI Tsutomu ll[ IJ
MJ (ColI. Sci., Rikkyo Univ.)
KIDERA Masanori'=!f iE]! (Fac. Sci., Kyushu Univ.)
KIKUCHI Tadashi *J itt! iE (ColI. Sci., Rikkyo Univ.)~ ~(Sci. Eng. Res. Lab., Waseda Univ.)
KOBAYASHI Misaki /J\
KOBINATA Hideo /J\ B 1oJ~~ (Fac. Sci., Univ. Tokyo)
KOMIYAMA Tatsuto ~ L1J j[ A (Sci. Eng. Res. Lab., Waseda Univ.)
KUBO Madoka 7--. f* Fq (Fac. Sci. Technol., Sophia Univ.)
KUROKAWA Meiko ~ ll[ I3JI --1- (ColI. Sci., Rikkyo Univ.)~(Fac. Sci., Tokyo Inst. Technol.)
MATSUDA Kiyohide ~ ill
MATSUZAKI Keiichi ~ ~ ~ (Fac. Sci., Univ. Tokyo)(ColI. Sci., Rikkyo Univ.)
MINEGISHI Junichi IIJ$ J¥ M! (Kyushu Univ.)
MITSUOKA Shinichi ~ [tliJ J{. MIYAZAKI Kousuke '8 ~ ~ 1r (Fac. Sci., Kyushu Univ.)
MIZOI Yutaka fl1=t ~ (Inst. Nucl. Study, Univ. Tokyo)
MOCHINAGA Kensuke :j;f 71< ~ 1r (Fac. Sci., Tokyo Inst. Technol.)
MORIYA Shingo ~ ~ tfi ~ (ColI. Sci., Rikkyo Univ.)
MURATA Tomoki 1'1 ill ~ W (Fac. Sci. Technol., Sophia Univ.)
ill fD {t. (Fac. Sci., Tokyo Inst. Technol.)
NAGATA Kazuhiko

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NAKAMURA Tad as hi q:t 1'1 iE (Sci. Eng. Res. Lab., Waseda Univ.)
NAKANO Jo q:t ff ~ (Inst. Nucl. Study, Univ. Tokyo)
NISHIO Teiji g§ If:. tj{ rs (ColI. Sci., Rikkyo Univ.)
NONAKA Takamasa ff q:t 1;ix iE (Fac. Sci., Univ. Tokyo)
NOTANI Masahiro ff ~ *f]A (Fac. Sci., Univ. Tokyo)
ODAHARA Atsuko IJ\EB,*J!f~ (Fac. Sci., Kyushu Univ.)
OGAMI Hiroshi If:. 1: t!!1 PJ (Fac. Sci., Tokyo Inst. Technol.)
OGAWA Hiroshi IJ'\ }I/ t!!1 ffBPJ (Fac. Sci., Tokyo Inst. Technol.)
OGAWA Hideto IJ\ }I/ ~ A (ColI. Sci., Rikkyo Univ.)
OGAWA Shinsuke IJ\ }I/ }\ ~ (ColI. Sci., Rikkyo Univ.)
L (Sci. Eng. Res. Lab., Waseda Univ.)
OKADA Hiroyuki 1M} EB
OTSU Hideaki~$ ~ B)'t(Fac. Sci., Univ. Tokyo)
OTSUKA TakanoriiN< .. f!@ (Fac. Sci., Univ. Tokyo)
SAITO Tomoki ii iJi %J:.mt (Seikei U niv. )SAITO Yoshitaka jf iJi 7i~.i (Fac. Sci., Univ. Tokyo)
SAKAMOTO Naruhiko !JJ:
pX. fJ;(Fac. Sci., Univ. Tokyo)
1t (Fac. Sci., Osaka Univ.)
SASAKI Mitsuru ftc/.{
SATO Hiroyasu ftc iJi 51..
(Seikei Univ.)
SATO Hiromi ftc iJi ]A i.fif (Fac. Sci., Tokyo Inst. Technol.)
SATO Yoshiteru ftc ni ~ 7Y! (Fac. Sci., Univ. Tokyo)
SATO Masaru ftc ni 11 (Sci. Eng. Res. Lab., Waseda Univ.)
SAWADA Shinya ~-i EB }\ -ill. (Fac. Sci., Kyoto Univ.)
SEKINE Takashi ~ fN ~.i (Fac. Sci., Tokyo Inst. Technol.)
SHIBATA Masataka ~ EB ~ j).i (Fac. Sci., Kyushu Univ.)
SHIMURA Masakatsu ~ 1'1 iE ~ (Fac. Sci. Technol., Sophia Univ.)
SHINODA Morihiko fll EB ~ fJ; (Sci. Eng. Res. Lab. , Waseda Univ.)
SHIRAKI Tadashi B
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SHIRAKURA Tetsuya B ~ 11& -ill. (Fac. Sci., Osaka Univ.)
SHIZUMA Toshiyuki ~ rj;!, {~11" (Fac. Sci., Kyushu Univ.)
if ~P] (Fac. Sci., Univ. Tokyo)
SUZUKI Kiyoshi ~~SUZUKI Masataka ~~iE ~ (Coll. Sci., Rikkyo Univ.)
TAJIMA Yasuhisa EB ~ ~),... (Fac. Sci., Tokyo Inst. Technol.)
TERANISHI Takashi ~ g§ r'fh (Fac. Sci., Univ. Tokyo)
TERASAWA Kazuhiro ~ if{ fD r$ (Sci. Eng. Res. Lab., Waseda Univ.)
TSUCHIDA Naohiko ± EB :ff fJ; (Fac. ScL, Univ. Tokyo)
X (Graduate Sch. Nagatsuta, Tokyo Inst. Technol.)
TUCHIDA Hideo ± EB
UCHIBORI Takeshi I*J t}ffi JEt PJ (ColI. Sci., Rikkyo Univ.)
UENO Hideki 1: ff ~(Fac. Sci., Tokyo Inst. Technol.)·UESAKA Tomohiro 1:!JJ: 1X ~$ (Fac. Sci., Univ. Tokyo)
WAKASA Tomotsugu ~ ~ ~ ooPJ (Fac. Sci., Univ. Tokyo)
WATANABE Yutaka if! ill fa. (Fac. Sci., Univ. Tokyo)
WATANABE Akira if! ill P}J (Sci. Eng. Res. Lab., Waseda Univ.)
YAMAMOTO Takuhisa LlJ~),...
(Fac. Sci., Tokyo Inst. Technol.)(Fac. Sci., Tokyo Inst. Technol.)
YAMASHITA Toshiyuki LlJ r ~IJ $YANAGISAWA Yoshiyuki fgp if{ ~ 11" (ColI. Sci., Rikkyo Univ.)
YONEDA Kenichiro *EBil-i!~ (Fac. Sci., Univ. Tokyo)
YOSHIDA Takuji 1§" EB 111 PJ (Coll. Sci., Rikkyo Univ.)
YOSHIMI Akihiro 1§" ~ ~ ~$ (Fac. Sci., Tokyo Inst. Technol.)

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ANDO Kozo $; ni ~IJ ~KAMBARA Tadashi t$
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KOJIMA Takao M. IJ'\ ~ ~ X
NISHIDA Masami g§ EB ~ ~SHIMAMURA Isao ~ ~H Jk**'*

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OURA Masaki
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TANG Jianzhi JlYOSHIDA Takashi* Chief Scientist,

WATANABE Naoki

V3£ $ i1[ tit** Senior Scientist*(Visitors)
AZUMA Toshiyuki{~1T(ColI. Arts Sci., Univ. Tokyo)
DANJO Atsunori tl 1: ~ ~ (Dept. Phys., Niigata Univ.)
DEPAOLA Brett D.
(Kansas State Univ., U.S.A.)
FUJIMA Kazumi Jii rl'l~ - ~ (Fac. Eng., Yamanashi Univ.)
FUKUDA Hiroshi
EEl(Sch. Administration and Informatics, Univ. Shizuoka)
HARA Shunsuke 1* {~1r (Dept. Gen. Educ., Tsukuba ColI. Technol.)
HARSTON Michael R.
(Dept. Math., Univ. Nottingham, U.K.)
HINO Kenichi B!f 11- (Dept. Appl. Phys. Chern., Univ. Electro-Commun.)
HULDT Sven
(Univ. Lund, Sweden)
HUTTON Roger(Univ. Lund, Sweden)
St Z. (Dept. Eng. Sci., Kyoto Univ.)
ISHII Keishi fi
ISOZUMI Yasuhito li+~~A (Inst. Chern. Res., Kyoto Univ.)
ITO Shin f1t Jii A (Radioisot. Res. Cent., Kyoto Univ.)
ITOH Akio f1t Jii f}( ~ (Fac. Eng. , Kyoto Univ.)
ITOH Yoh f1t Jii ~~ (Fac. Sci., Josai Univ.)
JAGUTZKI Ottmar(Univ. Frankfurt, Germany)
KAWATSURA Kiyoshi )11 mi ~ (Kyoto Inst. Technol.)
11 1: (Argonne Natl. Lab., U.S.A.)
KIMURA Mineo
KOBAYASHI Nobuo IJ':f* ffi X (Dept. Phys., Tokyo Metrop. Univ.).q: X (Fac. Sci., Himeji Inst. Technol.)
KOHARA Takao IJ,
KOIKE Fumihiro IJ' H!!. X tf (Sch. Med., Kitasato Univ.)
KOIZUMI Tetsuo 11', 7'R ~ X (Dept. Phys., Rikkyo Univ.)
KOMAKI Kenichiro IJ'4tliJf-.M (ColI. Arts Sci., Univ. Tokyo)
KOWARI Kenichi IJ, tlJ 11 (Dept. Chern., Tokyo Inst. Technol.)
KRAVIS Scott(Dept. Phys., Rikkyo Univ.)
KUROKI Kenro ~1I.M (Natl. Res. Inst. Police Sci.)
MARTINSON Indrek(Univ. Lund, Sweden)(Dept. Pat hoI. , Tokyo Med. Dent. Univ.)
MATSUO Takashi ~ ~MATSUZAWA Michio ~ i~ :im 1: (Dept. Appl. Phys. Chern., Univ. Electro-Commun.)
MITAMURA Tohru ~EEl11 11& (Fac. Eng., Himeji Inst. Technol.)(Nagaoka ColI. Technol.)
MIZOGAWA Tatsumi ~)II}.Pi E
MUKOYAMA Takeshi rDJ LlJ f~ (Inst. Chern. Res., Kyoto Univ.)
NYSTROEM Bosse(Univ. Lund, Sweden)
OHTANI Shunsuke{~1r(Inst. Laser Sci., Univ. Electro-Commun.)
OKUNO Kazuhiko ~!f f[] It (Dept. Phys., Tokyo Metrop. Univ.)
O'ROURKE Franceska(Dept. Appl. Math., Queen's Univ. Belfast, U.K.)
PAPP Tibor(Inst. Nucl. Res., Hungarian Academy Sci. , Hungary)
RICHARD Patrik(Kansas State Univ., U.S.A)
SALK Sung-Ho Suck
(Pohang Univ. Sci. & Tech., Korea)
SATO Hiroshi fti: Jii ?ii ~ (Dept. Phys., Ochanomizu Univ.)
SCHMIDT-BOCKING Horst(Univ. Frankfurt, Germany)
SEKIOKA Tsuguhisa ~ [tu] MrPj!A.. (Fac. Eng., Himeji Inst. Technol.)
SHIBATA Hiromi ~ EEl~(Res. Cent. Nucl. Sci., Univ. Tokyo)
SHIMA Kunihiro ~ ~ t-f (Tandem Accel. Cent., Univ. Tsukuba)
SHIMAKURA Noriyuki ~ ~Z. (Dept. Chern. , Niigata Univ.)
STOKLI Martin P.
(Kansas State Univ. U.S.A)
SUGER Jack
(Natl. Inst. Stand. Technol., U.S.A.)SULIK Bela (Inst. Nucl. Res., Hungarian Academy Sci., Hungary)
SUZUKI Hirosi j~
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TAKAYANAGI Toshinobu r'al fPP {~~ (Dept. Phys., Sophia Univ.)
TAWARA Hiroyuki ~ tf Z. (Natl. Inst. Fusion Sci.)TERASAWA Mititaka ~ ~ flfU.q: (Fac. Eng., Himeji Inst. Technol.)

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TSURUBUCHI Seiji tf4 ~JlN ~(Fac. Technol., Tokyo Univ. Agric. Technol.)
WAKIYA Kazuyoshi .IIiJ ~ ~ ~ (Dept. Phys., Sophia Univ.)
WATANABE Shinichi iJt ill. ffi ~ (Dept. Appl. Phys. Chem., Univ. Electro-Commun.)(ColI. Arts Sci., Univ. Tokyo)
YAMAZAKI Yasunori LlJ ~YOSHINO Masuhiro a!ff ~ v... (Lab. Phys., Shibaura Inst. Technol.)(Inst. Phys. Nucl. Eng., Romania)
ZORAN I. Valeriu
ZOU Yaming §~ irE I'IJ} (Jiao Tong Univ., China)-=*m(Students)
BITO Yasunori ~ Hi- ~ DI] (Fac. Eng., Kyoto Univ.)
KAGAWA Makoto if)1I A (Dept. Phys., Sophia Univ.)
KAGEYAMA Hiroyoshi ~ LlJ til ~ (Kyoto Inst. Technol.)
KAKUTANI Nobukazu jl:j ~ M ~ (ColI. Arts Sci., Univ. Tokyo)
KIMURA Yasuyuki *;t1 $ Z (Dept. Eng. Sci., Kyoto Univ.)
NISHIDA Tetsuo i§ IE T:r ft)} (Dept. Eng. Sci., Kyoto Univ.)
SANO Mutsumi ftc.!ff ~ (Dept. Phys., Rikkyo Univ.)
TAKAHASHI Ryohei rm fl f@: f(Kyoto Inst. Tecnol.)
TANABE Kunihiro IE ill. jJ)(Dept. Phys., Sophia Univ.)mMuon Science Laboratory
ISHIDA Katsuhiko ;fi IE JIg 1$
KIN 0 Yasushi *!ff ~ ~MATSUZAKI Teiichiro mlllijltt-m.f!B
WATANABE Isao ill ~ :f}J lit* Chief Scientist,

KADONO Ryosuke rfj!ff ~ :!11!
KOYAMA Akio /J\ LlJ ag lit
NAGAMINE Kanetada 7k ~ ~ ,t.*
YAGI Eiichi i\
5R ~***** Senior Scientist(Visitors)
AKAISHI Yoshinori iJr-;fi ~ *c. (Fac. Sci., Hokkaido Univ.)
FUJIOKA Manabu Hi- [M] ~ (Cyclotron Radioisot. Cent., Tohoku Univ.)
JONES E. Steven(Dept. Phys. Astronomy, Brigham Young Univ., U.S.A.)
KAMIMURA Masayasu 1:;t1 iE ~ (Fac. Sci., Kyushu Univ.)
KUMAGAI Kenichi 1f~ ~ 11 ~ (Fac. Sci., Hokkaido Univ.)
MACRAE Roderick Malcolm*
MATSUSHITA Akira m 1'" I'IJ} (Res. Dev. Co. Ltd., Japan)
MINAMISONO Tadanori i¥i III it. DIJ (Fac. Sci., Osaka Univ.),MIYAKE Yasuhiro -= ~ ~ f!!i (Meson Sci. Lab., Univ. Tokyo)
MORITA Masato ~ IE iE A (Fac. Sci., Josai Univ.)
STRASSER Partrick**
TORIKAI Eiko ,~. ~ -f- (Fac. Eng., Yamanashi Univ.)
WATANABE Tsutomu i1l-tfB f.J (ICU)* STA Fellow,** Postdoctral Researcher(Students)
DAWSON Wayne(Fac. Sci., Univ. Tokyo)

Magnetic Materials Laboratory
KITAZAWA Hideaki ~t ~
I'IJ}

*

OKADA Takuya[M] IE !j! -If! ** Senior Scientist

Plasma Physics Laboratory
OYAMA Hitoshi
LlJ ~

*

YANO Katsuki

jC!ff JIg*
221

Microwave Physics Laboratory
MIN 0 H Arimichi ~ HB t£ m

Semiconductor Laboratory(Visitors)
AONO Keiko W ff t! -T(CoIl. Liberal Arts, Kitasato Univ.)

Inorganic Chemical Physics Laboratory
AMBE Shizuko 17: $ fit --T
MATSUO Yukari m~m~~1j

MAEDA Kuniko
TAKAMI Michio

WjIE*I)--T
jWj ~

m ~*

* Chief Scientist(Visitors)
ARAI Nobuaki
1r {~'it (Dept. Fisheries, Kyoto Univ.)
ISHII Keizo ;;fi 1r It j§: (Cyclotron Radioisot. Cent., Tohoku Univ.)
KAWAI Jun fiiJ 1} iM (Dept. Metallurgy, Kyoto Univ.)*fi

Nuclear Chemistry Laboratory
AMBE Fumitoshi ti. $ )( fi!{*
ITOH Yoshiko W 7i --T
KOBAYASHI Yoshio /J\ ~'*~OHKUBO Yoshitaka *!zf*~r'iQ

*

•

=*
=*

ENOMOTO Shuichi tI~­
IWAMOTO Masako !6lE --T
MAEDA Haruka WjIE Lt G I)'>

* Chief Scientist(Visitors)
AMANO Ryohei 7C ff ~.:qz. (Sch. Allied Med. Prof., Kanazawa Univ.)
Jil (U niv. Electro-Commun.)
ASAI Kichizo i~ 1r(Fac. Sci., Osaka Univ.)
BABA Hiroshi ,~t!
ENDO KazutoY0:l% iJi fD ~ (Showa CoIl. Pharm. Sci.)FURUKAWA Michiaki E)II ~ IlJJ (Fac. Sci., Nagoya Univ.))1/iii: (ColI. Sci. Eng., Aoyamagakuin Univ.)
HARAKAWA Hiroaki
HASSLEIN Helmut(Shizuoka Inst. Sci. Technol.)
HIRUNUMA Rieko !Rfm~IJ~I --T (Showa ColI. Pharm. Sci.)
ITO Yasuo W iJi ~ ~ (Res. Cent. Nucl. Sci. Technol., Univ. Tokyo)
KANAZAWA Ikuzo 1t iR ~ ~ (Fac. Educ., Gakugei Univ.)
r>j" ~ (ColI. Sci. Eng., Aoyamagakuin Univ.)
KIMURA Kan(Sch. Hygien. Sci., Kitasato Univ.)
KOBAYASHI Takayuki /J\ t* .. Z
KOJIMA Sadao /J\ ~ ~ ~ (Nucl. Med. Cent., Aichi Medical Univ.)
MINAI Yoshitaka ~ ~ 1i.q: (Fac. Sci., Univ. Tokyo)
MURAKAMI Hideoki r>j" J:
J!. (Tokyo Gakugei Univ.)
NASU Saburo tJ~ 3Ji ~ f!~ (Fac. Eng. Sci., Osaka Univ.)
SAITO Tadashi :ti iJi ii1[ (Fac. Sci., Osaka U niv.)
SHIBATA Sadao ~ IE ~ X (Natl. Inst. Radiol. Sci.)(Inst. Nucl. Study, Univ. Tokyo)
SHIBATA Seiichi ~ IE IDJX SHINOHARA Atsushi 1'rl rnt Jf. (Fac. Sci., Nagoya Univ.)
SHINONAGA Taeko 1'rl 71< ~y --T (Fac. Sci., Tokyo Metrop. Univ.)
TANAKA Akira IE I:j:l iii: (Showa ColI. Pharm. Sci.)
YAlTA Tsuyoshi R ttt ~~ (JAERI, Tokai)
YANAGA Makoto R 7k IDJX A (Jikei Univ. Sch. Med.)YOKOTA Yuko ;{lIE m --T (CoIl. Sci. Eng., Aoyamagakuin Univ.)
YOKOYAMA Akihiko ;{l Llr IlJJ ffi (Fac. Sci., Osaka Univ.)
YOSHIDA Yutaka S IE ~ (Shizuoka Inst. Sci. Techno!.)

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222

(Students)
AOKI Naoki -W =* ND fit (ColI. Sci. and Eng. , Aoyamagakuin Univ.)
FURUTA Riko il m ~ T(Showa ColI. Pharm. Sci.)HAGIWARA Tetsuya ~~ -tf!
(Fac. Sci. and Eng. , Tokyo Denki Univ.)
HARUTA Hiroshi ~ EB t-f P] (Showa ColI. Pharm. Sci.)
IIJIMA Yoshihide ijt ~ E8
(Fac. Sci. , Toho Univ.)
INOUE Takakazu
to (Fac. Sci., Osaka Univ.)
ITOH Naoya. #t ii~t(CoIl. Sci. and Eng., Aoyamagakuin Univ.)
IWATA Maki ;fi*~(Fac. Sci., Toho Univ.)(Fac. Sci., Osaka Univ.)
KASUGA Ryouichi ~ B $! KIKUCHI Yasuhisa *J ft1!.
7-.. (Fac. Sci. and Eng. , Tokyo Denki Univ.)KIRYU Shigetoshi 1/11] 1: ~ ~IJ (Fac. Sci. , Nagoya Univ.)
KOBAYASHI Kanako /l'-;.t*W*-=t- (Fac. Sci., Tokyo Metrop. Univ.)
KOIZUMI Yukiyo IJ . . 7~ ¥ -tit (Tokyo Gakugei Univ.)
KUWABARA Kazunori ~ 1m to 1! (Shizuoka Inst. Sci. Technol.)a5- (Showa CoIl. Pharm. Sci.)
MINAMI Hiroshi Wi
MIYABAYASHI Kyoko B:f* J¥- T (Showa CoIl. Pharm. Sci.)
MUKAI Kazuhiko ~ to 1$ (Fac. Sci. , Osaka Univ.)
MUROYAMA Toshiharu ~ LiJ {~a5- (Fac. Sci. , Nagoya Univ.)
NAKAGAWA Akihiro ~ )11 ~(Shizuoka Inst. Sci. Technol.)
NAKAJO Terunobu ~ f~ ~ 1$ (Tokyo Gakugei Univ.)
NAKAMURA Jin ~:f-t t(Univ. Electro-Commun.)(Fac. Sci. , Nagoya Univ.)ODA Hirotaka IJ . . EBt~ ~(Fac. Sci., Univ. Tokyo)
OHTSUKA Hiroshi
ffi L (Tokyo Gakugei Univ.)
ONIZUKA Nobuyuki
OSHIMA Nagayasu~ 71<(Tokyo Gakugei Univ.)
OTSU Yoko "*~! 11 -=t- (Tokyo Gakugei Univ.),M (Fac. Sci. , Tokyo Univ.)
OZAKI Takuo Jf. iIffif
SASAKI Jin ftI:.q=* t(Tokyo Gakugei Univ.)
SATO Yoshihiko ftI: jfj B ~ (Fac. Sci. , Nagoya Univ.)
SUZUKI Akihiro i~ =* • Hi (Shizuoka Inst. Sci. Technol.)
TAKAHASHI Yoshio rm~ ~(Fac. Sci., Univ. Tokyo)
TAKESAKO Kazuhiro tJ J§. to a5- (Fac. Sci., Osaka Univ.)
TAKESHITA Kazutaka tJ T to:4 (Fac. Sci., Toho Univ.)
TSUKAHARA Kazuhiro ~ 1m to 5.L (Shizuoka Inst. Sci. Technol.)'**..1:"

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ur

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Chemical Dynamics Laboratory,KIMURA Kazuie =*:f-t - f(Visitors)
KAZAMA Shigeo

J!\. rfl' Ii it(Students)
YOSHIKANE Takao(Dept. Phys., Chuo Univ.)a ~ ~i 1:

Cellular Physiology Laboratory
HAN AOKA Fumio 1£ 1M] )( it*
YATAGAI Fumio :frEBJt)(~**(Dept. Phys., Chuo Univ.)

KITAYAMA Shigeru~t LiJ~~* Chief Scientist, ** Senior Scientist(Visitors)
ANDO Koichi 1i ii ~ (Natl. Inst. Radiol. Sci.)
FUKUMURA Akifumi m:f-t IlJJ ~ (N at I. Inst. Radiol. Sci.)
FURUSAWA Yoshiya il ~~ {£ -tf! (Natl. Inst. Radiol. Sci.)
HAM A Yoshimasa ~ • {§ (Sci. Eng. Res. Lab. , Waseda Univ.)223

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HASHIMOTO Shozo ~~ ~(Fac. Med., Keio Univ.)
HOSHINO Kazuo £ lff ~ i( (Natl. Inst. Radiol. Sci.)IIZUKA Masayuki ~ ±j( JE Z (Natl. Inst. Radiol. Sci.)
ITO Hisao W~ 7((Fac. Med. , Keio Univ.)
ITOH Hiroko W Jii ~ -f- (Natl. Inst. Radiol. Sci.)(Natl. Inst. Radiol. Sci.)
ITSUKAICHI Hiromi 1i B -ml}7:J h
Jt I'IJJ (Natl. Inst. Radiol. Sci.)
KANAI Tatsuaki 16:
KASAl Kiyomi 11.
m (N at I. Inst. Radiol. Sci.)
KAWACHI Kiyomitsu fiJI IAJ m:7't (Natl. Inst. Radiol. Sci.)
KIKUCHI Masahiro *J:ttB JE tf (JAERI , Takasaki)
KIMOTO Masafumi
5f: JE ~ (Natl. Inst. Radiol. Sci.)
KOBAYASHI Yasuhiko /J\ t* ~"ffi (JAERI, Takasaki)
KOHNO Toshiyuki iPJ lff 13t Z (Natl. Inst. Radiol. Sci.)
KOIKE Sachiko /J\ it!!. -¥ -f- (Natl. Inst. Radiol. Sci.)
KOJIMA Eiichi /J\ ~ 5R ~ (Natl. Inst. Radiol. Sci.)
KOSAKA Toshifumi /J\:I:Jj 13t)( (Dept. Vet. Radiol., Nihon Univ.)
KUBOTA Nobuo ~ m :§: 7( (Fac. Med., Yokohama City Univ.)
MATSUFUJI Naruhiro :.m jJi nX: 5.L (Natl. Inst. Radiol. Sci.)
McINTYRE Cindy L.
(Radiobiol. Unit, Med. Res. Counc. , U.K.)
MINOHARA Shinichi it ffii 1$ ~ (Natl. Inst. Radiol. Sci.)MIYAHARA Nobuyuki g ffii {g -¥ (Natl. Inst. Radiol. Sci.)
MURAISO Chidori f1 ~ ~(N at I. Inst. Radiol. Sci.)
MURAKAMI Masahiro f1 1: JE rJ.L (N atl. Inst. Radiol. Sci.)
rJ.L fD (Dept. Agric. , Shizuoka Univ.)
NAKAI Hirokazu ~OHARA Hiroshi
ffii 5.L (Dept. Gen. Cult. , Okayama Univ.)
OKUMURA Toshiyuki ~ *1 fix Z (Fac. Med. , Univ. Tsukuba)
SASAKI Hiroshi ft.~* 5.L (Fac. Med. Kyushu Univ.)
SOGA Fuminori ~:ft)( g(Inst. Nucl. Study, Univ. Tokyo)
SUDO Michio ~JUii*~i( (Natl. Inst. Radiol. Sci.)TAGUCHI Yasuko
IJ ~ -f- (Natl. Inst. Radiol. Sci.)
TAKATUJI Toshihiro !Wi U 13t(RI Cent., Nagasaki Univ.)~
11 (Natl. Inst. Radiol. Sci.)
TANAKA Kaoru
TATSUZAKI Hideo 1L ~X (Fac. Med., Univ. Tsukuba)
TOMURA Hiromi . ~ *1 ~(Natl. Inst. Radiol. Sci.)
TSUBOI Atsushi Pf(Natl. Inst. Radiol. Sci.)
TSUBOUCHI Susumu Pf IAJ :it (Suzuka Med. Technol. Univ.)
WATANABE Hiroshi ~ ill.
(JAERI, Takasaki)
WATANABE Masami ~ ill. JE G (Fac. Pharm. , Nagasaki Univ.)
YAMASHITA Shoji Ll.J 1'" ~;}( (Natl. Saitama Hospital)

*

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f*

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(Students)
FUJI Hiroshi Uim (Fac. Med. , Univ. Tsukuba)
KAWASHIMA Mitsuhiko iPJ ~ :7't"ffi (Fac. Med. , Univ. Tsukuba)
TAKAHASHI Hideyuki !Wi-¥ (Fac. Med., Univ. Tsukuba)m*

Microbial Toxicology Laboratory
YAMAGUCHllsamu tlJ IJ J3** Chief Scientist

224(Visitors)
WATANABE Tadakazu~ $ ,~, ~(Students)
MATSUMOTO Ken-ichi

:.m

* 1t

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(Agro-Kanesho Co. Ltd.)(Shimane Univ.)

Safety Center
HARASAWA Kaoru 1* iR •INOUE Yoshio
J::. ~ X
KATOU Hiroko 110 ii tf "1MATSUZAWA Yasuhide ~ iR
SAKAMOTO Ichiro ;I:Jj
Jl~
TAKI Kenro ff! ~Jj,N,ij

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*- *

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INAMURA Takashi T. fIB~;j" !j!*KAGAYA Satoru 110~~ tg
KOTOU Takeo 110 ii JEt itt
MIYAGAWA Makoto g )11 A ~SHINOHARA Shigemi rti 1*
UWAMIN 0 Yoshitomo J::. it ~ ijJ=ja c.

* HeadSurface Characterization Center
IWAKI Masaya ;fi
iE ~*

*

ffi

KUMAGAI Makoton~ ~YATAGAI Fumio~IEJt>cx** HeadRadioisotope Technology Division
NAKANO Kazushiro 1ft ff f(] ~* Head(Visitors)
IJIRI Kenichi
1M. (Radioisot. Cent., Univ. Tokyo)
ISHIKAWA Masanobu ;fi)/I ft {Fe (Tokyo Univ. Fisheries)
KASE Youko 110 ~ ~~"1- (Natl. Inst. Radiol. Sci.)
KAGAWA Yasuhiro 1ft )11 ~ tif (Toray Research Center Inc.)
MAEZAWA Hiroshi M ~(Fac. Med., Tokai Univ.)
OGURA Koichi /J-.. ~ *0: (ColI. Ind. Technol., Nihon Univ.)
1* ~ (Dept. Gen. Cult., Okayama Univ.)
OHARA Hiroshi
ft itt (Fac. Pharm. , Nagasaki Univ.)
SUZUKI Masao j~
YATO Osamu ~ yj til (Kagoshima Agr. Exp. Stn.)

*m

*

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(Students)
HAMANAKA Kenichi
MATSUMOTO Hideya~ 1ft 11 -

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(Fac. Sci. Eng., Waseda Univ.)(Fac. Sci. Eng., Waseda Univ.)

225

AUTHOR INDEXABE Ryo

~

IWJ$

3, 6

CURRIE P. J.

JE1r. •ADACHI Minoru

34,41,42, 128.Ei~~IJJ't

AIHARA Toshimitsu

AKAGI Hiroyasu . Jffi***

5

3, 6

140

DEPAOLA Brett D.

72

DOKE Tadayoshi

m~V~,.

EATON Gordon H.

175

AKEBOSHI Yoshihiro

I3JJJlUf~~

55

EGELHOF PeterAKIYOSHI Hiromichi

fKa~3'E

121, 131

EGUCHI-KASAI Kiyomi!»iT ~~$~x

AKUTSU Takao

36

32,33

40, 43AMANO Ryohei~ff A1f90

FERRAGUT Alain

AM BE Fumitoshi*$:>cfi5c

34, 80, 86, 87, 89, 90, 92,

FUCHI Yoshihide93, 94, 95, 96, 97, 98, 99,

FUJIMAKI Masaki

101, 102, 136

FUJITA Jiro

ANDO Kozo

FUJITA Satoshi

93, 94, 95, 96, 97, 98, 101

FUJITA Shin

111, 119*JfiJ4tl~

68, 69, 70*Jfi~ii

ANDO Yoshiaki

37

W=Jt =* 31, 38, 41, 42
AOKI Jiro W*PJ.M 76
AOKI Yuka W*El:Jw 56

AOI Nori~ff=Jt{~~ARAI Nobuaki;fi,~!1~ A

ARIMA Akito
ARUGA Takashi;fiJ(

ASAHI Koichiro;/t!!,

ASAI Kichizo

140, 141, 143

AWAYA Yohko

119

m-!1~

i~=Jtaiii

1iEB~fD

FUKUDA Tomokazu

1i:f1"I3JJ ~106

FUKUNISHI Nobuhisa

1ig§~f.';j12, 16, 21

1i~$~~-J-

111, 114

itJII~PJJ

99,100FURUKAWA MichiakiitiR-ffi-tl!.
itEBf.I-J- 86

34, 41, 42, 128

FURUTA Riko68, 69, 71, 72, 74, 75, 129

FYFE W. S.

=Jtffltz.

34

GOLOVKOV Mishael

BEHR Karl-Heinz

36

GONO Yasuyuki

BELBOT Michael

38

GOTO Akira

BERTSCH George

67

GEISSEL Hans

55

36
36

~.~z.

fiKi

~

156, 158, 160, 162, 163, 165,
166, 168, 170, 172, 178

36

BOCHKAREV Oleg

39

36

HaBLEIN Helmut

102

HACKE Marcus

79

HADA Takashi

3131 EB f.';j ~BURKARD Karlheinz

36

HAMA Yoshimasa~

CARLSON Brett Vern

20

HAMADA Shingo

itEBJU~

T~~I3JJ

76• .!§'

107
53~ rp!it107:fE1M.I:>C!i 109, 110~ r-F1r
46, 47, 49, 125

HAMAN AKA Kenichi37~ i*tF' 50, 51, 54
CHIBA Toshiya T~~IJ~ 5, 163, 165, 166, 168
CHAE Soo Joh

CHIBA Yoshiaki

50, 51, 53, 54, 122

3, 6, 76, 103, 147, 148, 150, 152,

55

CASTEN Richard F.

55, 5655,56

140

BEAUME Didier

BRUNLE Adolf

110, 111, 114, 118

it~fD~Jt

FURUTAKA Kazuyoshi

BABA Hiroshi ,~:t£100
BATYGIN Yuri
166, 170, 172

BOYD Richard N.

31

FUKUMURA Akifumi

GALONSKY Aaron

BIZARD Guy

46, 47, 49, 125

KiEB m 58, 183, 184, 186,187, 188
FUJITA Tatsuru iiEB !it 121
FUKUDA Mitsunori 1iEBJ'tJIIJ{ 40,43
FUKUDA Shigekazu 1iEBlt- 40, 43

FUTAMI Yasuyuki*

32, 33, 39

3, 6, 148

KiEBrg~101~l.i~-J-48

FURUSAWA Yoshiya

25
~

~

Ki~iEmFUKUTSU Kumiko139

m:fr~~

ARATANI Michi

85, 86, 87, 89, 90

50, 51, 54~

iiEB=f!~83, 84, 85, 86, 87, 89, 91, 92,

86, 87, 89;jI*~-ENOMOTO Shuichi*iiJ!.-ANDO Koichi

113, 114,
115:i!iifD~

ENDO Kazutoyo

ALONSO Jase R.

*{iB~-J-IT IJ (1i:=Jt) m~

76

ALEKSANDROV Dmitrii V.

AMBE Shizuko

130

5

HANAOKA F'umio
HARA Yousuke

HARADA Akihiko~EBng~~ IB

CHLOUPEK Frank

39

HARADA Toru

CHRISTIE William

35

HARAKAWA Hiroaki

CHULKOV Leonid

36

HARASAWA Kaoru

II!

40,43
28

~)II mili

~iR

•

93

101

*

:fr~Wm!i

HASEBE Hiroo~*fg'!!,ij

ISHII Tetsuro

5

HASHIMOTO Masashi ~*~~ 134
HASHIZUME Akira m; JR !!,ij 145, 146

53~:Ij(it~

ISHIZUKA Takeo

44,45-1!!. if

ISSHIKI Hiroshi

3,6

HASUIKE Katsuhito~H!!.JjJ A

130

ITO Hisao#t Jii.:!A..x.

117

HATANAKA Kichiji!tIII~Eta

46, 47, 49, 125, 148

ITO Naoya#tJii.rl~~

93

HATSUKAWA Yuichi

MJII!i-

51,53,54

HAYAKAWA Kazuo!f-J11-1:

102

ITO Yasuo #tJii.~~ 103
ITOH Yoshiko #t)f.(7j-r 103, 104~JtifXit

HEMMI Masatake5, 163, 165, 166, 168

HIRAI Masaaki.Ifl*iE I=IJI

HIRATA Daisy

19, 20, 35, 36

IWAMOTO Masako

HIROSE Takayuki

JAi.lq:~HIRUNUMA Rieko

IImfrJff -r

HOFMANN Helmut

3, 6

HONMA Toshihiro *rlt'~JA 158
HORI Nobukazu ~ {§- 119
HORI Yoichi~~-:!JffiHORIBATA Takatoshi
HUI Qin24

68, 69HUTTON Roger

37

IZUMI Hideaki

ili*~I=IJI

41, 42IZUMIKAWA Takuji}RJII!ii1iJ

JAGUTZKI Ottmar

75, 129

36
~

~I!I

44, 45

KADONO Ryosuke

r'ff~~

78, 135, 174

KAGAWA Yasuhiro

wJllmm109

KAGEYAMA Tadashi~LlJ

KAMBARA Tadashi:t$ffl't if.

KAMIGAITO Osamu

l:::ij[j}{I~-iE

mITif-r 30
mffl't !ii

118

68, 69, 71, 72, 74, 75,*ili lJ5itta*JJ£lDx. 37'

IDEGUCHI Eiji~ft~*C.

IIMURA Hideki~*Jll=lJI

3,6

KANAI Yasuyuki~*1*z

38, 50, 51, 53, 54, 122

KANAZAWA Ikuzo

106, 110, 111, 113, 114, 115,
116, 117, 118, 119

KASAGI Jirohta
KASE Masayuki

53

ijt:l:*iEfi

119

IKEDA Yasubumi}@'B3~X

37

IKEGAMI Kumio}@'l::1L~~IIZUKA Masayuki}@'iR~=~iR fj ~103~*ta!!~*
hoi8~ Z ·55, 563, 6, 76, 103, 130, 147, 148,
156, 158, 160, 162, 163,

hoifj~~-r

KASE Youko109

JtLlJitliJ

KATAYAMA Takeshi

5, 1654-* ff 132
IMAMURA Mineo 4-ft*!i 58
mHllffij A

68,69,71,72,74,75

165, 166, 168

3, 6, 148

180, 182

hoJii.*ffi 61
KATO Hiroshi hO. t4 132

IMAI Takashi

INABE Naohito

3, 6, 163, 165, 166,
168, 172

KANAI Tatsuaki

34, 46, 47, 48, 49, 58,
124, 125

mJII~~=ICHIKAWA Ryuji

IKEZAWA Eiji

3, 6, 147, 150, 165
129

B31J~-r

ICHIHARA Takashi

IEKI Kazuo

43

68,69

HYODO-TAGUCHI Yasuko
ICHIE Hiroko!6i£rlt

JIN Wei-Guo

41, 42, 128~ilM:q:{~IWASA Naohito

JANAS Zen non

77

HULDT Sven34, 83, 84, 85, 92, 93, 94,
95, 96, 97, 98

86, 87, 89

141*rlt'~iz

HONMA Takayuki

113, 114, 115

7, 142!6*if.-r

76

23*B3 5lx.

HONDA Hiro-omV 6 h!6*iEtiX

IWAKI Masaya

31, 381i. B

ITSUKAICHI Hiromi

KATO Daiji

3, 6, 34, 76, 156, 158, 160,
163, 165, 166

KATO Mineo

hnJii.~1:

134

KATO Seigo

hOJii.fit¥

46, 47INAMURA Takashi T. mift !ii 44, 45, 58, 183, 184
INOKUCHI Sad'aki mIJ jtfM 116

KATO Toshiyuki

hnJii.{~*

130

KATOH Kenichi

hOJii.ll-

46, 47, 48, 49, 124, 125

INOKUTI Mitio

KATSURAGAWA Hidetsugu* IJ :iR1: 65

INOUE Masahiro*

IRNICH Hartmut

36

ISHIDA Katsuhiko~B3JjJ~

ISHIDA Nobumichi~B31$:iR

ISHIDA Satoru

l::~51~B3

ISHIHARA Masayasu
ISHII Keishi
II

~*.z

37

KAWACHI Kiyomitsu

mrgfflJ'tiM

137, 138

KAWAI Jun't!

JIIrlt,trMt

KAWAMA Tetsuo

130

KAWAMURA Naritoshi~ffl'tiE~

70

iPJ~

59, 134, 135, 174, 175, 176
46, 47, 48, 49, 124, 125l1}1I~HUP]

KELLER Horst

106

3,6, 156

iPJftmt~59

36

12, 31, 34, 37, 38, 41,

KIDERA Masanori*~if.~

42, 48, 50, 51, 54, 122

KIKUCHI Masahiroii":ttBiEif 108ii":i:tB iE 37

KIKUCHI Tadashi

44,45,133

50,51,53,54

KIM Eunju

1t

!N~

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KIM Jong Chan

LIU Guanhua

58~*

50, 51, 54

1t tEl! 17
KIMURA Kan **1" ~ 93
KIMURA Kazuie **1" -~ 105**t:~ ~l

KIMURA Mineo**1"*1::*r m 10438, 50, 51, 53, 54, 122~

14, 15, 28

tf

M~

116

MAlE Takeshi .*~± 3, 6
MARTINSON Indrek
68, 69~B3~llfJ

MASUDA Kimiaki

130;mEBm~

55

MATSUDA Kiyohide

108

MATSUDA Sumio

80

MATSUFUJI Naruhiro;mJii1JX:~

106

MATSUMOTO Hideya

;m**~

107

iii

~tw

KITAZAWA Hideaki~t~*llfJ

KOBAYASHI Akiko

1j"**BBB-i=- 109
Ij,**_Z 143

KOBAYASHI Takayuki

Ij';f,M~il;mEB*'1!~

76;m*!i!-

MATSUMOTO Ken-ichi

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YOSHIDA Noriaki{I~

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YANAGA Makoto

23, 29

LlJl'l§;}(YAMASHITA Shoji

12, 16. YOSHIDA Atsushi

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YAMADA Nobuyoshi*ff~

YANOKURA Minoru

98

180, 182

YABANA Kazuhiro

165, 166, 168, 170, 172,

31,32,33,37,38,39

102

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