ISSN 0289-842X

RIKEN
Accelerator
Progress Report
vol.

18

理化学研究所the Institute of Physical and Chemical Research

RIKEN Acce/ermor Progress Report ~ (Q) (6) ~January-December U'71 (Q)~Jm 11: $. :fiff ~ pJT
the Insfifvte of Physical and Chemical Research
Wako-shi, Saitama, 35'-0' JAPANEditorss. AmbeY. Awaya

Y. GonoT.Inamura

H. Kamitsubo

s. Kitayama

M.OderaT. Watanabe

E. Yagi

This volume contains recent information of the accelerators at RIKEN (IPCR), informal
reports and abstracts of papers which will be published at scientific meetings or in publications
by staff members, guests, and visitors.

All rights reserved. This report or any part thereof may not be reproduced in any form (including photostatic or microfilm form) without written permission from the publisher.

CONTENTS
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II.

III.
1.

INTRODUCTION

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1

OPERATION OF ACCELERATORS
1.

Cyclotron Operation ......................................

2.

RILAC Operation ......

3. ,TANDETRON-Operation. " ...................... : ...

4.

Implanter Operation ...

00••••••••

0' ,, '•••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••

'

,

'

•••••

2
4

6

7

RESEARCH ACTIVITIES
Nuclear Physics, 1.

27Al( d, 2He )27Mg Reaction ............................. ~ . . . . . . . . . . . . . . . . . .. 82.

. Investigation of Coulomb Excitation for Projectile-Polarization
Determination ........ .................................. .......... " ....... 10

3.

Strongly Damped Components in the Reaction of 160+54Fe
System ................... '........................ '.............. ',' ...... 12

4.

Extended TDHF Calculation of the Variance of Mass
Distribution in the 160+40Ca Reaction at E Lab = 157.3 MeV ................... 14

5.

Low Angular-Momentum Cutoff in Heavy-Ion Fusion
Reactions . .
0

2.

0

••••••••••••••••••••••••

0

•••••

••

• • • • • • • • • • • •'••.• • • • • • • • • • • • • • •15

6.

Backward Cross Section in the Generalized Exciton Model ........ . ........... 18

7.

Classical Trajectory Picture of Massive Transfer ...................... .- ....... 208.

High Spin States in llOSn

9.

Lifetime Measurement of the 8- State in llOSn

10.

High-Spin States of Ge Isotopes in the Interacting- Boson Model ............... 26

11.

Ground State Rotational Band in 173Yb Excited by (58Ni, 58Ni') ........., ....... 28

12. 'In-Beam r-Ray Study of 218Ra with BGOACS

13.

In-Beam r-Ray Study of 212po Using Radioactive 210Pb Target, ,.: ..... .-....... 32

14.

Isomeric Transition of 212PO

15.

Evaporation-Like Products in 14N+23SU Reaction .. . .' ....... .- .. .- ............. 37

16.

High-Lying Single-Proton States of 209Bi Studied by Gamma-Triton" dence M easurement m. t
he20SPb(.
C OlnCla , t )209B'1 ReactlOn... . ............... . 39

17.

Production and Separation of Neutron-Rich Isotope 15C Using
Heavy-Ion Reactions ..................................................... 41................................................ 22.... . ......................... 24.. . ........................... 30.............................................. 35

Atomic and Solid-State Physics
1.

Classical Trajectory Monte Carlo Calculation for Collision
Processes of e++(e-p) and P++(,lCp) ....... : .........................: ...... 43

Page
2.

Quantum Mechanical Study of the Process ,u++Clrp) ~ (,u+,u-)+p .............. 45

3.

Transitions of Molecules between High-Angular-Momentum States

4.

Theoretical Investigation of Molecular Photoionization ........................ 49

5.

Doubly Differential Cross Sections for Electron-Impact
Ionization of Helium ...................................................... 51

6.

Potential Energy Curves of Na2+, K 2+, and Na2

7.

Electronic Property of Extremely High-Density and llighTemperature Materials .................................................... 55

8.

Electron Stripping Cross Sections from Multiply Charged Ions byHydrogen and Helium Atoms .............................................. 57

9.

Coupling in Ar-Ti, Ar-Co, and Ar-Zn Systems ............................... 59

10.

Theory of Radiative Electron Capture I: Nonrelativistic
Treatment and Theoretical Paradox ........................... '............. 62

11.

Theory of Radiative Electron Capture II: Covariant Treatment ................. 64

12.

Calculation of the L2a-MIMI Auger Energy and the Relative Auger
Rates for Ar6 + .......................................................... 67

13.

Tilted Foil Method Using Thin Carbon Foil ................................. 69

14.

Beam-Foil Spectroscopy of Highly Ionized Aluminum Atoms .................. 71

15.

Intensity Ratio between Kfi and Ka X-Rays from 33 MeV Ar Ionsin Solid Targets .......................................................... 73

16.

High Resolution Measurement of Cu K X-Rays from Collision
Systems of Cu Ions on C Target and C Ions on Cu Target .................... 75

17.

REC X-Rays for 3He and 4He Targets ...................................... 77

18.

Production of Highly-Charged Slow Ar Ions Recoiled in
1.05 MeV amu- l Arq+ (q=4, 6, 10-14) Ion Bombardment ...................... 78

19.

Total Apparent Cross Sections for Ionization of Rare-Gas Atoms by
Fully Stripped Projectiles ................................................. 80

20.

Production of Highly-Ionized Recoil Ions in Highly-Ionized,
Energetic Ion + Molecule Collisions ......................................... 82

21.

Projectile Dependence of L-MM Auger Electrons Ejected fromAr Target by Heavy-Ion Impact ............................................ 84

22.

Secondary Electrons Emitted from Al under Bombardmentwith He+ and He++ ....................................................... 86

23.

Chemical Bond Effects on Auger Electrons Induced by He 2 + Ion
Bombardment ........................................................... 88

24.

Studies of Magnetic Structure of Cobalt Ferrite Surfaces by
119Sb Emission Mossbauer Spectroscopy .................................... 90

25.

Perturbed Angular Correlation of r-Rays Emitted from
111Cd ( -+- 111In) in a-Fe20a ........................................... ' ... 92

26.

TDPAC of r-Rays Emitted from 111Cd ( -+- 111In) in Fea04 .................... 94............ 47.............................. 53

Page

3.

27.

Perturbed Angular Distributions of Gamma-Rays from Dy underTransient Magnetic Field ................................................ 96

28.

Plasma Wall Interaction .............................. . ................... 97

29.

Origin of Hydrogen in Amorphous Silicon Produced by
Glow-Discharge in Si2H 6 +D2 and Si2D 6 + H2 ................................ 99

30.

Application of Heavy-Ion RBS to the Analysis of Silicon Ohmic
Contact Systems ........................................................ 101

31.

Depth Profiling of Deuterium in Titanium Carbide by Elastic Recoil
Detection Analysis ...................................................... 103

32.

Stress-Induced Site Change of H in V Observed by ChannelingExperiments ............................................................ 104

33.

Lattice Location of Hydrogen in Nb a-Phase as Observed by
Channeling Method .................................................... 106

34.

Compositions of Anodized Aluminum with Europium Implantation ............ 108

35.

Surface Compositions of Argon-Implanted Kapton Films

36.

Lamp Annealing of Cd-Implanted GaP ..................................... 110

37.

Helium Bubble Formation in Ni .......................................... 111

38.

Creep Property Improvement of Helium Injected JPCA by
Thermomechanical Treatments .......................................... 113

39.

Irradiation Creep of 316 Stainless Steel ..................................... 115

40.

Depth-Dependent Damage Profile in Stainless Steels Irradiatedwith Ar- and N-Ions .................................................... 117

41.

Effects of Fast Neutron Irradiation on Insulating Materials.................... 109.................. 119

Radiochemistry and Nuclear Chemistry1.

Isotope Production and Labelled Compound Synthesis ....................... 121

2.

Charged Particle Activation Analysis

3.

Charged Particle Activation Analysis of Ion-Implanted Oxygen ................ 125

4.

Application of PIXE to Environmental Science............................. 126

5.

Application of PIXE to Medical Science (II)............................... 128

6.

Reliability and Detection Limit for the Elastic Recoil Measurementof Hydrogen ........................................................... 130

7.

Measurement of the Impurity Hydrogen Concentrations on
the Surfaces of the Neutron Bottle ........................................ 132

8.

High Sensitivity Analysis of Deuterium in Solids by 15N-Induced
Nuclear Reactions ....................................................... 134

9.

Thermoluminescence from the Ar-Bombarded Silica

10.

Adsorption Kinetics of 119Sb(V) Ions onto a-Fe20a Surfaces...................................... 123........................ 137. ............... 139

Page

4.

5.

IV.

11.

In Situ Emission Mossbauer Study of 119Sb5 + ( ~ 119Sn 4+) Ions at
a-Fe203-Aqueous Solution Interfaces ............................. .......... 141

12.

Correlation between Angular Anisotropy of Fission Fragment andIts Mass in System of p+ 232Th ................................. : ........ 143

Radiation Chemistry and Radiatiqn Biology
1.

Electron Scavenger Effects on the Fluorescence Induced bySingle High-LET Particle .......... ... ................................... 145

2.

Inactivation of Bacterial Spores by a Single Heavy Ion (II)3.

DNA Damage in Cultured Human Tumor Cells after Nitrogen-Ion
Irradiation .............................. . ...... .. ..................... 148

4.

New Broad Emission Bands from Pressurized Liquid He Impinged by
N Ions ................................ .. .............................. 150

Instrumentation

1.

RIKEN BGOACS System ............................................... 152

2.

A Compound Counter System for High-Energy Gamma-Ray
Detection .............................................................. 155

3.

Liquid Ionization Chamber ............................................... 156

4.

Use of Charge Integrating ADC's with Pulse Shape Discriminators
for Neutron-Gamma Discrimination ....................................... 158

5.

Particle Identification with a BaF2 Scintillator ................................ 160

6.

Test of MCP and PSD Using X-Rays and Electrons

7.

One Dimensional Position Sensitive Parallel Plate Avalanche Counter ........... 164

8.

Test Machine for Ion Guide Isotope Separator On-Line

9.

A Coulomb-Excitation Mossbauer Spectrometer ............................. 167........................ 162..................... 166

NUCLEAR DATA

1.
V.

.................. 147

Status Report of the Nuclear Data Group .................................. 168

ACCELERATOR DEVELOPMENT

1." 'Present Status of the RIKEN Ring Cyclotron Project ........................ 169

2.

Sector Magnets for the RIKEN SSC ...................................... 170

3.

Model Study of. the RF Resonator for the RIKEN ~SC ...................... 172

4.

RF Power Amplifier for the RIKEN SSC ..... ~ ............................ 174

5.

A Method of Measuring Two-Dimensional Motion of the Orbit Center
Using Three Radial D~fferential Probes ........... ; ........................ 177

6.

Acceleration of Off..;.Centered Beam in the RIKEN SSC ......... ~ ............ 179

7.

Beam Sharing System for RIKEN S-SC ........... '.......... " .............. 181

Page

VI.

8.

Design of Beam Buncher in the SSC Injection Beam Transport Line .......... 184

9.

Control System of the RIKEN SSC ....................................... 185

10.

An Intelligent CAMAC GP-IB Controller Module .......................... 187

11.

Method of Sealing Vacuum Chambers and Pumping Control
System for the SSC .................................................... 189

12.

Performance Test in Cryopump

13.

Calculation for the Design of a Beam Dump ................................ 194

14.

Beam Attenuation Device ..........•..................................... 197

15.

Emittance Monitor ...................... . ............ . .................. 199

16.

Charge Exchange Technique in the Linac .................................. 201

17.

Design of a Rebuncher in RILAC

18.

Production of Highly Charged Ions by Whistler Heating of Plasmas ............ 205

19.

Construction of ECR2

20.

Automatic Control of a Gas Circulation and Gas-Feed System for
the Ion Source ......................................................... 209

21.

Low-fi RFQ Structure-II: High Frequency Model Measurement

22.

Development of the Medium-fi RFQ Structure-III: Study by HighFrequency Model ....................................................... 212

23.

Development of the Medium-,B RFQ Structure IV: Effect of Change
of Cell Length, Measurements by Magnetic Analog Models ................... 214

24.

Application of the Medium-fi RFQ Structure ............ . .................. 216.......................................... 192........................................ 203.............................. . ... ................ 207............. 211

RADIATION MONITORING
1.

Leakage-Radiation Measurement in the Underground Passage of
the Cyclotron Building .................................... . ..... .. ...... 218

2.

Routine Monitoring of RIKEN Accelerators ................................ 221

VII.

LIST OF PUBLICATIONS ................................................... 223

VIII.

LIST OF OUTSIDE USERS AND THEIR THEMES ......................... 234

IX.

LIST OF SEMINARSX.

LIST OF PERSONNEL ...................................................... 236
AUTHOR INDEX....................................................... 235

'1

I.

INTRODUCTION
H. Kamitsubo

Collaborative research using the 160 cm cyclotron
and the variable-frequency heavy-ion linear accelerator (RILAC) has been extensively performed
this year. In addition to these two accelerators, anelectrostatic accelerator (TANDETRON) of 1 MV
and an ion implanter of 250 kV are dedicated to thecollaborative research.
During the past one year the cyclotron has beenin good condition as before. A new. gas feed systemwith an automatic control device for gas circulation
was developed for the cyclotron ion source. The
RILAC has also been operated steadily in thisperiod. It should be emphasized that the operation
in a full frequency range (17-45 MHz) was realized.
Studies of the dynamical behavior of the beam in the
RILAC as well as the technical development of theaccelerator itself have been performed. A beam
attenuation device was developed to reduce beam
intensity down to 10- 4 without deteriorating thebeam quality. The RF power can be reduced if ionswith higher charge states are accelerated at the
RILAC. Test experiments were carried out topromote the ion charge states by putting a stripper
foil between resonator cavities. The T ANDETRON
has been in steady operation in this period.
A variety of studies on the nuclear physics havebeen carried out mainly by using the 160 cm cyclotron. Nuclear spectroscopy and reaction mechanism
for heavy ion collisions were studied experimentallyas well as theoretically. Collaborative experiments
using the facilities of other institutions such as
Institute for Nuclear Study, University of Tokyo,
Research Center for Nuclear Physics, Osaka University, and Japan Atomic Energy Research Institute have also been continued.
Instrumental development has been continued
for the purpose of building new experimental
equipments for the SSC. Construction of a BGO
crystal ball was almost completed and used for thetest experiment. Development of the ion-guided ion
source for an on-line mass separator was started in
1984.

Atomic and solid state physics has been continued
in this period. The RILAC is very suitable for the
study of atomic collisions because it is capable ofaccelerating various kinds of ions to a few MeV per
nucleon. Experiments were carried out on the beam
foil spectroscopy and atomic collisions measuring
ultra-violet light, X-rays, Auger electrons, andrecoil ions; theoretical work was also performed
extensively.
Mossbauer spectroscopy and perturbed angularcorrelation studies have been continued to investigate the internal fields and structure of the magnetic
oxides. Studies on the distribution and lattice location of the impurity atoms in solid materials havebeen pursued using the channeling and the Rutherford backscattering techniques.
Collaboration with the group of National ResearchInstitute for Metals was continued to study thecreep and helium-bubble formation in fusion reactor
materials by bombarding with alpha particles aswell as protons.
Charged particle activation analysis has been
applied routinely to the measurements of the lightelement impurities in GaAs, Sb-doped Si, andother semiconductors. Experiments on the radiation
chemistry and biology were carried out mainly byusing heavy ions.
Construction of the RIKEN Ring Cyclotron(separated sector cyclotron) is in progress. During
past one year the construction of the cyclotron vault
was completed and four sector magnets together
with their power supplies were assembled in it.
Fabrication of remaining parts of the cyclotron is
now under way.
International collaboration between RlkEN and
Cyclotron Laboratory of Texas A&M University
has been persued on heavy ion physics. The International Symposium on Heavy Ion Physics coorganized by RIKEN and INS, University of Tokyo,
was successfully held last August in Tokyo (Part 1)
and at the foot of Mt. Fuji (Part 2).

2
RIKEN Accel. Progr. Rep. 18 (1984)

II.

OPERATION OF ACCELERATORS
1.

Cyclotron Operation

K. Ikegami, S. Fujita, K. Ogiwara, H. Takebe,
S. Kohara, T. Kageyama, and I. Kohno

The 160 cm cyclotron was operated on the 24 hr
a day basis during the period from October 23,
1983 to November 7, 1984. Statistics of machine
operation time is shown in Table 1. Percentage ofthe net beam time slightly decreased comparedwith that of the last year. In this period, mucheff01;t has been made for fast and easy setting up of
Table 1.

Cyclotron operation in the period XIX.
Oscillator

Reading of the time meter on
Oct. 23, 1983
Reading of the time meter on
Nov. 07, 1984
Difference
Percentage of 382 daysIon
sourceBeam

81,388.5 85,751.2 49,788.5
86,420.1 90,909.0 53,950.1
5,031.6 5,157.8 4,161.6
54.9% 56.3% 45.4%

Schedule in this period
240 days
Beam time
Overhaul and installation
60
Periodical inspection and repair 20
Vacation and holidays
48
Other scheduled shut down
14

Table 2.

Scheduled beam time and research subjects in the period XIX.
Subject

Nucl. Phys.
Fields other thanNucl. Phys.

Outside users

the operation parameters for any ions and energies
by using a small computer1) (NEC 9801) equippedto the control system.
In January 1984, the newly designed gas circulation and gas-feed systems 2) for the ion source were
set up. The gas circulation system is used in order toreuse expensive gases such as 3He and enriched
13C02 and 15N2 • The gas-feed system is used inorder to feed eight kinds of gases; it has two gasfeed lines for mixing gases through two gas flow
controllers. These systems can be operated automatically according to the sequence predeterminedby a programing controller which consists of an
OMRON SYSMAC M5R having an I/O port ofmax. 256 points.
At the end of March, 1984, the cyclotron was
shut down for two weeks. Because a 450 kW motor
generator (MG) supplying DC power for the main
magnet was broken down. The trouble would havebeen caused by a reason that some parts of insulatorsof armature coils were covered with dusts of carbon
brushes .and destroyed by the flashover between

Nuclear reaction
RI production
Nuclear chemistry
Radiation biology
Radiation chemistry
Solid state physics
Atomic collision
Radiation damage
Radiation damage
RI production
Test of track detector
Single event upset in the LSI memory
Radiochemical analysis

Total
Percent in total
Maintenance, operation, and engineering
Exchange of ion sources
Machine inspection and repair
Total

Heavy ion

2,250
34
0
64
216
0
24
69
46
0
0
116
0
2,819
53.6%

Light ion
(hr)

838
167
374
12
56
210
0
353
291
37
11
0
89
2,438
46.4%
108
480
588

Total

3,088
201
374
76
272
210
24
422
337
37
11
116
89
5,257
100%

3

K. Ikegami, et al.

Table 3. Distribution of beam time
among particles accelerated.
Particle

(hr)

(%)

P
d
3He1+
4He 2+
Be 3+
12C4+

878
263
230
1,067
166
301

16.7
5.0
4.4
20.3
3.2
5.7

a)

I Particle
13C4+
14N4+
14N5+
15N4+ a)0 5+
N e6 +
Total

(hr)

(% )

142
312
358
120
960
460
5257

2.7
5.9
6.8
2.3
18.2
8.8
100

Newly accelerated ion.

commutators. It took three months to repair andoverhaul the motor generator. During the threemonths, a small 250 kW motor generator, which had
been used for the 1/3 model magnet, was used
temporarily. The maximum energy for heavy ionsaccelerated was limited owing to the small powerof the motor generator.
Table 2 shows the beam time allotment to various
research activities in the period XIX. The totalscheduled beam time decreased by about 300 hr, as
compared with that of the last year. Requirement

for heavy ion beams decreased by about 1,000 hr
and for light ion beams increased by about 1,000
hr. The use
light ions increased for the studies
of nuclear reaction and radiation damage. The 89
hr in the scheduled beam time were alloted to the
new study of radiochemical analysis of semiconductor materials by outside users.
Table 3 shows the distribution of the scheduled
beam time among particles accelerated. The beamtimes for proton, deuteron, and alpha increased incontrast to the decrease for heavy ions. 15N4+ ion
was newly accelerated and utilized for performing
several experiments such as nuclear reaction. The
ion source with sputtering electrode3) was used to
extract high intensity beams of Be3+ ions.

ofReferences
H. Takebe, S. Fujita, and K. Ogiwara: RIKEN Accel.
Progr. Rep., 17, 186 (1983).
2) K. Ikegami, T. Noda, N. Kamiyama, and I. Kohno:
Proc. 8th Symp. ISIAT 84, Tokyo, p. 115 (1984).
3) . K. Ikegami, T. Kageyama, and I. Kohno: Jpn. J. Appl.
Phys., 19, 1745 (1980).

1)

4
RIKEN Accel. Progr. Rep. 18 (1984)

11-2.

RILAC Operation

Y. Miyazawa, M. Hemmi, T. Inoue, T. Kambara, M. Yanokura, M. Kase,
T. Kubo, E. Ikezawa, K. Kihara,* Y. Chiba, and M. Odera

The RIKEN heavy-ion linear accelerator, RILAC,
has been in steady operation in this period andvarious kinds of ion beams were supplied to va~ioustargets. Table 1 gives statistics of operation in the
period September 1, 1983-August 31, 1984. A beamtime shows a decrease of 3.50/0 compared with thatof the previous period, because of machine trouble
and shut down for power saving. In this period, thescheduled beam time for 6 days was cancelled bytrouble in a motor-generator supplying AC powerof 50 kVA to the 500 kV high voltage terminal of
the injector. Figure 1 shows statistics of ions usedin this period. Most of users preferred to Ar 4+ ion,and a half of the total beam time was used for thisions. Accelerations of AI, Cu, and He ions werealso requested frequently and percentages of their
Table 1. Statistics of operation in the periodof Sep. 1, 1983-Aug. 31, 1984.

Total

Energy (MeV In)%

Days
Beam time
Frequency change
Overhaul and improvement work
Periodical inspection and repair
Machine trouble
Scheduled shut down

beam times to the total were about 10%> for metal
ions and 150/0 for He ion.
In the spring of 1984, a temporary improvement l )was made to the driving circuits of the main power
amplifiers to get stable operation and to apply higher
voltage 'to accelerating gaps in the resonators in afrequency range of 17 to 40 MHz. By this improvement, the operation of the linac became simpler andeasier than before in changing frequency. The useof an automatic frequency setting device,2) though
it is still limited, allows setting of many parametersof the resonators and oscillators feasible. Figure 2
shows the relations among energy per nucleon,
frequency, and effective acceleration voltage. The
ions having the mass to charge ratios Mjq=2-10,
such as He 2+, N3+, Ne 3+, Ne 4+, and AI3+, wereincreased in its maximum energy by the improvement and supplied to the users in the improved

155
14
55
27
6
109

42.3
3.8
15.0
7.4
1.7
29.8

366

100

1

0.5

2

I

3

4 5

I

i

I

i

I

I

25
20

>

15

~

80

Q)

tl.O

70

~ 10

60

>

u
u

50

ro

40

Q)

>

:;:;

30

u
~

Vl

~ 20
Q
10

I q

R

m
1

m

12

2

2"3

2

I

2

2 3

II .
3

4

I
I
I
I
I

5

I

;1 1111.1 II

Charge
state

I

LiJ

45

I

I
I

_

n 1m
9

89

Fig. 1. Statistics of ions used in the period of Sep. 1, 1983Aug. 31, 1984.

* Sumijyu Examination and Inspection Corporation.

Beam accelation realized
up to Oct. 1984
r:==J Beam accelation is possible
but is not done yet.
I

15

"

I

I

I

20

,

I

!

!

I

,

!

"

. , ' ! ,1"

30
40
Acc. freq. (MHz)50

Fig. 2. Relations among energy per nucleon, frequency, andeffective acceleration voltage. The number on each line isMjq, the ratio of the mass of ion to the degree of its ionization.

Y. Miyazawa, et al.

condition. When an Ar4+ ion beam is accelerated at
frequencies above 28 MHz, the injector voltage andaccelerating voltage of each resonator are limited by
the maximum ratings of their power supplies.
Therefore, in this case it is necessary to use an Ar5+

5ion beam which has tendency to contain 0 2+ ions.
References
1)
2)

Y. Chiba: Private communication.
Y. Chiba: IPCR Cyclotron Progr. Rep., 14, 120 (1980).

6-:iUKEN Accel. Progr. Rep. 18 (1984)

11-3.

TANDETRON-Operation

H. Sakairi, T. Kobayashi, E. Yagi, and T. U rai

The machine was operated for 140 days of one
year from November, 1983: 110 days for experiments and 30 days for tests. About 100 days werealloted to overhaul, repair, and installation.
Subjects of experimental studies were as follows:(a) Depth profile of implanted ions(b) Effect of implantation on surface composition(c) Laser annealing effects on damage caused by
implantation(d) Lattice location of hydrogen atoms in metals(e) Microanalysis of oxygen in semiconductors
These studies were performed by the following
laboratories:(1) Inorganic Chemistry Lab. (for (a) and (b) )(2) Deformation Processing Lab. (for (a) and(b) )(3) Friction and Lubrication Lab. (for (a) and(b) )(4) Semiconductors Lab. (for (c))(5) Metal Physics Lab. (for (d) )(6) Nuclear Chemistry Lab. (for (e))(7) Cyclotron Lab. (for tests)(8) Beam Analysis Center (for (a), (b), and (d) )Ions accelerated for these studies were 4He 2+,
3He 2+, and B2+. At the exit from the ion source,

current intensities of 4He-, 3He-, and BO- were 1.3
pA, 0.6 pA, and 8pA, respectively. At the exit fromthe accelerator, current intensities of 4He 2+, 3He2+,
and B2+ were about a third or a quarter of theabove values at the exit from the ion source. The
highest acceleration energy was 2. 7 MeV for 4He 2+,
and 3He 2+ ions and 2.1 MeV for B2+ ions.
Construction of an additional beam transporting
system with an ion optical prism for an electron
microscope for the in situ observation of damage processes in irradiated materials was almost completed
and a test operation is going to start. Other several
improvements were carried out satisfactorily invacuum systems and electronics linking the measuring system with the control system of the accelerator.
Main troubles occurred in the ion sources as in
the last period. Deterioration of a lithium boiler ofthe charge exchanger, coupled to a duoplasmatron,
shortened the interval of lithium supply to one thirdof the normal period. The present boiler has beenused for three and a half years. A new boiler is inpreparation at the workshop. A cesium gun in the
sputtering ion source also broke down because of
corrosion and was exchanged with new one. It is
the second breakdown and the lifetime of the gun
is ascertained to be two years.

7
RIKEN Accel. Progr. Rep. 18 (1984)

11-4.

Implanter Operation
M.Iwaki

The RIKEN 200 kV Low- and High-Current
Implanters were described in detail in previous
reports. 1),2) These machines have been utilized insurface-layer modification of materials such as
metals, insulators, polymers, and semiconductors.
Main subjects under practice are as follows:(1) Compositions, chemical bonding state, andstructure of ion-implanted iron and steel
plates(2) Mechanical and electrochemical properties
of ion-implanted iron and steel plates(3) Compositions, chemical bonding state, andstructure of ion-implanted diamonds andglassy carbons(4) Electrical and electrochemical properties of
ion-implanted diamonds and glassy carbons(5) Compositions, structure, and electrical propetties of ion-implanted Kapton and polyacetylene sheets(6) Preparation of stan:dard samples for secondary-ion mass spectroscopy (SIMS)(7) Improvement of durability of tools by
nitrogen implantation
In order to perform surface-layer modification oftools of various shapes by nitrogen implantation, thethird implanter was set up. This implanter, called
Z-100, was designed and constructed by Zymet
Inc., U.S.A., as shown in Fig. 1. Its implantation
system specification and implant characteristics are
as follows:

(1)
(2)

Beam energy: 50-100 keV
Ion species: N+ (.......,40%)+N2 +( .......,60%).
In additjon to implanting with nitrogen, themachine can also be used to implant all elemental materials which exist in gaseous form
simply by attaching an appropriate gas bottle
and an evaporation oven: 0, CI, As, Cd, Sb,
etc.
(3) Ion current: about 5 rnA(4) Ion beam shape: Approx. 3 em wide X 20
cm high at a processing position at maximum
voltage(5) Typical dose: 2 X 1017 ions/cm2(6) Implant area: 250 cm 2 (circular)(7) Ion density: 125 pA/cm2 (electrical) withina beam spot and 12.5 pA/cm2 (electrical)
average over an implant area(8) Implant time: <30 min/batch for single
surface objects and <90 min/batch formultiple surface objects using disk rotation(9) Throughput: > 1 batch/hr for single surface
objects(10) Implant uniformity: Better than ± 10%
over 250 cm 2(11) Implant angle: Variable between 0° and±90°(12) Product cooling: Materials to be implanted
may be embedded in a water-cooled tray
filled with a eutectic alloy or fastened on awater-cooled holder in order to keep thetemperature of the treated area from exceeding 200°C(13) Control system: Microprocessor based system to communicate with stations of subassemblies via a serial bptical loop(14) Vacuum system: Two sets of a 6 inch oil
diffusion pump backed with a mechanicalrotary pump
The machine has been used for nitrogen implantation in·various tools such as injection moulds, PCB
drills, and scissors for a barber, and many materials
modified by nitrogen implantation are under apractical test in industry and in our institute.
References

Fig. 1.

Implanter Z-100 constructed by Zymet Inc., U.S.A.

1)
2)

M. Iwaki: RIKEN Accel. Progr. Rcp., 15,7 (1981).
M. Iwaki: ibid., 17,7 (1983).

8
RIKEN Accel. Progr. Rep. 18 (1984)

III.

RESEARCH ACTIVITIES
1.

Nuclear Physics

S. Kohmoto, M. Ishihara, and T. Kubo

NUCLEAR REACTION[

27AI(d, 2He)27Mg and 27AI(d, PP)27Mg'1

E=2~ MeV; m~asured energy spectra. Spin-flip and/or spin-non-flip

reactlOn mechamsm.

The system of two protons has no bound state;
however, simultaneous detection of two protons
under small-relative-energy conditions makes it
possible to restrict the quantum state of the system
to L=O, 8 = 0 and T= 1. We call this system 2He.
If the relative energy is not small enough, therestriction L=O is not guaranteed and 8= 1 component may be involved. Also protons from evaporation process may be observed in such geometry. We
designate this system pp.
When compared with other charge-exchange
reactions producing neutron-excess nuclei such as(n, p) and (d, pp), the (d, 2He) reaction is characterized by spin-flip (Ll8= 1) transition.
On the other hand, (n, p) and (d, pp) reactions
may contain both spin-flip and spin-non-flip (Ll8=0) transitions. Because of this peculiarity, we proceeded with a trial study of the (d, 2He) reaction.
Figure 1 shows a schematic diagram of the 2He
detection system. Two identical sets of JE-E counter telescopes consisting of a 50 p.m and a 2,000 p.m
thick Si detectors were collimated by using 7 mm X

7 mm slits which were separated vertically by 9 mm.
At 11 cm away from the target, this system covers anangular interval of 812=5°-13°. Thin AI foil was used
1.70 5/ 2+
1.94 5/ 2+ / 0.98 3/ 2+

7

2 Mg

I IIi I'"I

g'nd 1/2+

II I I

100

.ec
::l

0

u

'0
~

(l)

.0

50

E
::l

Z

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

El+E2 (MeV)(a) 27 AI (d,2He)27Mg

B= 25·

.ec
::l

o

~100
o
~

(l)

.0

E

::l

Z

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

E 1+E2 (MeV)(b) 27AI(d,pp)27Mg 01=-82=25·

Fig. 1.

Schematic diagram of the 2He detection system.

Fig. 2. (a) Energy spectrum of the reaction 27 AI( d, 2He)27Mg at 0=25°, where E1 +E2 is the sum of the kinetic energies of the two protons. The solid lines are drawn throughthe data points to guide eye. (b) Energy spectrum of thereaction 27Al(d, pp)27Mg at 81 = -02=25°, i.e. 81 2= 50°
and (J=O°.

S. Kohmoto, et al.

as target. A 24 MeV deuteron beam was furnishedby the cyclotron.
Figure 2 displays our preliminary results; Fig.
2(a) is an energy spectrum of the reaction 27AI(d,2He)27Mg at ()=25°.
The 1/2+ ground state, 0.98 MeV 3/2+ state,(1.52 MeV 5/2+ state+1.70 MeV 5/2+ state) andanother at about Ex=3.6 MeV of 27Mg are relatively well populated. For comparison, we measured
a spectrum of the 27AI( d, pp )27Mg reaction at()1=25° and ()2=-25°, which is shown in Fig. 2(b).

9Among the low-lying states of the residual nucleus,
only the ground state is strongly populated in thisreaction. Though it is not possible to compare these
spectra rigorously because of the different directionof the recoil nucleus, it is obvious, however, that
two reactions proceed in a rather different way.
Compound reaction component may not be ignoredin the latter reaction. We are preparing measurementof angular distribution of the reaction 27AI( d, 2He)27Mg to see if the spin-flip (or spin-non-flip) process
is the main one to be considered.

10
RIKEN Accel. Progr. Rep. 18 (1984)

111-1-2. Investigation of Coulomb Excitation for
Projectile-Polarization Determination
H. Ohsumi, M. Ishihara, S. Kohmoto, K. Sugimoto, *T. Tanabe,* and H. Hamagaki*

NUCLEAR REACTIONS 27AI(27AI, 27AI')27AI*, E=35.5MeV:j[ measured left-right asymmetry, 27Al-r coincidence.

We have been studying nuclear spin polarization(P) of heavy ions produced by means of the tilted
foil method. 1) Here we report investigation of a new
method 2) for determination of P, which utilizes theleft-right asymmetry in the Coulomb excitation. In
the Coulomb excitation process, especially in theforward-angle scattering and in the excitation withan adiabaticity parameter ';>0.1, the angular mo~~mentum in the direction of hr X hi is favorablytransferred, enhancing the excitation of, for example, JM=-2 for a E2 transition (see Fig. 1),3)-+-+
where kr and k i are the wave vectors of scatteredand incident ions, respectively. In the case of apolarized projectile, the angular distribution isaffected by the vector coupling between the polarized projectile-spin and the transferred angularmomentum, giving rise to a left-right asymmetry
proportional to P. The analyzing power is usuallylarge, and even close to unity when the excitation
occurs between states with stretched spin sequencessuch as 1/2+ -+ 5/2+, 5/2+ -+ 1/2+. The method is
supposed to be particularly useful for ions withrelatively high energies, where the cross section
for the Coulomb excitation becomes large, while
the conventional method using circular polarizationof visible light in the decay of excited ions is lessefficient because of the reduced cross section forsuch an atomic excitation process.
In order to study the feasibility of the technique,a preliminary measurement of the Coulomb excitation of 27AI projectile was made using 35.5 MeV(-..1.3 MeV/A) unpolarized beam from RIKEN
heavy-ion linear accelerator (RILAC). The 27Al
nucleus was chosen, since it can give rise to a
stretched-type excitation from the 5/2+ g.s. to the
1/2+ state (Ex =0.84 MeV), which affords a large
analyzing power. The experimental setup is shownin Fig. 2. An 27Al foil target of 200 pg/cm2 inthickness was used temporarily. Scattered particles* Institute for Nuclear Study, University of Tokyo.

were detected by two Si solid-state detectors placed
at ± 60° symmetrically with respect to the beam
direction. The detectors of 400 mm 2 were used,subtending a solid angle of 0.15 sr. This angle waschosen by optimizing the balance between a larger
cross section for the Coulomb excitation and alarger ratio of the Coulomb excitation to the
Rutherford scattering. The latter factor is important
for the efficiency of the method since the counting
rate is limited primarily by the number of elastic
events. The detected particles were registered incoincidence with gamma rays emitted from Coulomb-excited levels. This affords separation of
Coulomb excitation events from intense elastic

Projectile Coulomb Excitationk·+Ze(target)-~- - ------e--- - -Fig. 1. Schematic figure of an angular momentum transfer
in the E2 Coulomb excitation. The angular momentum inthe direction of hr X hi is transferred by the predominantcomponent with the magnetic substate M = - 2.

27 Al

Beam

Fig. 2. Schematic figure of the nuclear polarization measurement system installed at C course in RILAC.

11

H. Ohsumi, et al.

Channel number

Fig. 3. Gamma-ray spectrum measured in coincidence with
scattered 27 Al particles. Gamma-rays are emitted from the
Coulomb excited-levels.

events and, furthermore, identification of the channel of the Coulomb excitation. The gamma rays
were detected with two 31 ¢>x3" NaI detectors
placed normal to the reaction plane. Each of themcovered a solid angle of 2.2 sr.
Figure 3 shows a gamma-ray spectrum obtainedin the coincidence measurement. Two peaks corresponding to the excitations of g.s. ~ 1/2+ (E x =0.84
MeV) and g.s. ~ 3/2+ (E x = 1.01 MeV) are well
separated. A coincidence rate of ,...,.,,0.3 cps for theg.s. ~ 5/2+ transition was found to be accessible
under the present experimental conditions. These
results well assure the feasibility of the method to
be used for determination of the projectile polarization. Such a measurement could be soon madewith the setup as shown in Fig. 2 by placing atilted-foil in the entrance section of the scatteringchamber.
References
1)
2)
3)

S. Kohmoto, M. Ishihara, T. Nomura, and Y. Gono:
RIKEN Accel. Progr. Rep., 17, 48 (1983).
K. Sugimoto, T. Tanabe, T. Hattori, K. Haga, N.
Shikazono, and J. Ichimura: INS Ann. Rep., 1983, 36.
K. Alder and A. Winter: Rev. Mod. Phys., 28, 432 (1956).

12
RIKEN Accel. Progr. Rep. 18 (1984)

111-1-3.

Strongly Damped Components In the Reaction of
16
0 + 54Fe System

K. Sueki, 1. Kohno, M. Magara,* Y. Hamajima,**
Y. Hatsukawa,* and H. Nakahara

NUCLEAR REACTIONS 160+54Fe, total reaction cross ]sections, evaporation-residue cross sections, strongly damped[
components.

The strongly damped components in the 16 0+
54Fe reaction, especially, for symmetric mass split
products were analyzed on the basis of a diffusion
model 1) as well as a rotating liquid drop model 2)
for fission. We performed a Goshal-type experimentthat has the same compound nucleus with similar
excitation energy. We chose the 160 + 54Fe reactionthat has the same compound nucleus as the 20N e+
50Cr reaction reported previously.3)
The systems studied, the conditions for compound-nucleus formation, and its decay by fission
are summarized in Table 1.
The experiments were performed using the cyclotron. An enriched self-supporting 54Fe target of
600 pg/cm 2 in thickness was bombarded with 128
MeV 16 0 5+ ions. The reaction products weredetected with a JE-E counter telescope consistingof a gas proportional JE and a 300 pm thickness
solid-state E detector. 4) The products with atomic
numbers from 5 to 20 could be identified, and theenergy spectra and angular and charge distributionsof each product were obtained.
The angular distributions of elastic scattering andevaporation residue products in the 160+54Fe reaction at 95 to 128 MeV were measured by a timeof-flight method using cyclotron beam bunching.
A start pulse and particle energies were obtained bya silicon surface barrier detector, and the RF trigger
pulse was used as a stop pulse. Elastic scattering andTable 1.
Reaction

evaporation residues were measured to obtain the
total reaction cross sections O'R and the evaporation
residue cross sections O'ER, respectively. The results
shown in Fig. 1 were also used to determine thegrazing angular momentum 19r and the critical angular momentum lerit. In 160+54Fe at 103.5 and 128
MeV, 19r was 50 Ii and 63 Ii, respectively, and lerit
was 41 Ii and 43 Ii, respectively.
The energy distributions of products with Z~
10 showed single bell-shaped kinetic energy peaksin the region of the strongly damped components.

2.0

1.5

1.0

0.5 LL----J--......1-0--L- .l..----l.....----J-- ...J.- ---'--.L...J
0 0 150 O1
l/Ecm (MeV- l)
Fig. 1. Measured evaporation residue (fusion) cross sections
and total reaction cross sections as a function of 1 jEem for
16 0 + 54Fe. The dashed line represents the values predictedby Bass. 5)

Summary of the conditions for compound nucleus formation and its decay by fission.

CompoundnucleusFissility(Z2jA)

70S e

16.5

16 0 + 54Fe

2oNe+ 5O Cr

Elab

E*CN

(MeV)

(MeV)

lmax(h)lerit(h)Bf at lerit

128.

100.

63±2

43±3

12.0

140.

105.

63±2

49±1

5.0

'" Faculty of Science, Tokyo Metropolitan University.

"'* Faculty of Science, Kanazawa University.

K. Sueki, et ai.

13

140 MeV 2° Ne + 50Cr
• ---- 128 MeV 160 +54 Fe
8<111=40·

0 8 1ab

• 20·
25·
• 30·
~ 35·
.. 43·o10 -1 ~-L_~~_~~_~_~~~

4

6

8

10

12

14

16

18

20

Z

0.1 L----L._L-----L_L---L-~_'_:=__:_'_::__;:t;:_'4
6
8 10 12 14 16 18 20
Z

Fig. 2. Charge distributions at various laboratory angles in
128 MeV 160+54Fe.

The angular distributions du/dO for the productswith Z~ 13 showed almost constant in the centerof-mass system. Thus, these products (Z~13) areconsidered to be either fusion-fission fragmentsor reaction products emitted after interaction time
longer than the time required for one rotation of
the composited system. The charge distributions
for various angles are shown in Fig. 2. The charge
distribution at Ocm=40° is compared with that of
the 140 MeV 20Ne+ 50Cr reaction as shown in
Fig. 3. The difference in yields of symmetric fragments (Z~ 13) is probably explained by the effectof the different critical angular momenta.

Fig. 3. Charge distributions in two different reaction systems:
140 MeV 2oNe+ 50 Cr and 128 MeV 160+54Fe. The solid line
shows the distributions calculated by the diffusion model1) in
140 MeV 2oNe+ 50 Cr and the dashed line in 128 MeV 160+
54Fe. The calculations are normalized to the data for Z = 13
observed in 140 MeV 2oNe + 50 Cr.

We continue similar experiments on 103.5 MeV
160+ 54Fe and 120 Mev 12C+58Ni, and analysis of
the experimental results are in progress.
References
1)
2)
3)
4)

5)

W. Norenbrg: j. Phys. C5, 37, 141 (1976).
S. Cohen, F . Plasil, and W. J. Sweitecki: Ann. Phys. (N.
Y.), 84, 557 (1974).
Y. Nagame, H. Nakahara, K. Sueki, H. Kudo, I. Kohno,
and M . Yanokura: Z. Phys., A, 317, 31 (1984).
M. Yanokura, I. Kohno, and H. Nakahara: Oyo Butsuri,
49, 1095 (1980).
R. Bass: Nucl. Phys. A, 231, 45 (1974).

14

RIKEN Acce!. Progr. Rep. 18 (1984)

111-1-4.

Extended TDHF Calculation of the Variance ofMass Distribution in the 16 0 +40Ca Reaction
at ELab ==157.3 MeV
S. Yamaji and M. Tohyama

Extended time-dependent Hartree-F ock theory, Mass
[ distribution, Deep inelastic collision.

The mass distributions in the 160+40Ca collision at E Lab = 157.3 MeV were studied in the timedependent coupled-cluster approximation(TDCCA),
which is one of the extended time-dependent
Hartree-Fock (TDHF) theories taking the effect of

10.---~---------------------,

157.3 MeV 16 0 +~O Ca• Experimental value\10= - 400 MeV'fm 3\10=-530 MeV·fm 3o~~~~~~~~~~~~~~

45
FusionDeep inelastic
collision

Peripheral
scattering

Fig. 1. The variance of mass distributions vs. initial angularmomentum 1 in the 160+40Ca reaction at ELab=157.3
MeV. The shaded area between Vo= -400 and -530 MeV·
fm 3 shows TDCCA results. Vo is the strength of the residualinteraction of o-function type. One observed value extracted
from the experimental mass distribution 3 ) is shown by a dot
at 1=56 fl.

1

two particle - two hole excitations into account.
We have studied the variance of mass distribution in slab collisions in our previous work. 1) In
the present note, we briefly report the results of
the realistic three-dimensional calculations, thedetails of which are given elsewhere. 2)
Figure 1 shows the variances (J ~ of mass distribution calculated in TDCCA and TDHF as afunction of the initial angular momentum I. It canbe seen that the variances (J~ in TDCCA are enhanced by a factor 10,.....,30, as compared to (J~ in
TDHF.
Thus, the obtained TDCCA results reproduce
the order of magnitude of the large experimental
variance of mass distribution, which has not been
predicted successfully by the standard TD HF
theory.
References
1)
2)
3)

M. Tohyama and S. Yamaji: Phys. Lett. B, 123, 16 (1983).
S. Yamaji and M. Tohyama: ibid., 147, 399 (1984).
H. Ikezoe, D.G. Kovar, G. Rosner, G. Stephans, E.
Ungricht, B. Wilkins, C. Maguire, Z. Kui, W. C. Ma,
S. Robinson, D. Watson, G. Word, T. C. Awes, and G.
Young: private communication.

15

RIKEN Accel. Progr. Rep. 18 (1984)

111-1-5.

Low Angular-Momentum Cutoff In Heavy-Ion Fusion
ReactionsT. Nomura, S. Kohmoto, K. Sueki, K. Morita, T. Kubo,
H. Kudo, M. Adachi,* and H. Kawakami**
NUCLEAR REACTION 16 0 (15N, xnypzar), E=45-80 MeV;
19F (12C, xnypzar), E=42-80 MeV; 27Al (a, xnypzar), E=2S58 MeV; 160 (160, xnypzar), E=55-95 MeV; 28Si (a, xnypzar),
E=25-58 MeV; enriched 28Si target; measured Er, Ir; deduced
excitation functions of some evaporation residues. Evaporation
calculation; low-l cutoff in fusion.

High-spin states in a highly excited light nucleus
decay preferentially by evaporation of a particles,
while low-spin states deexcite mainly by emissionof nucleons. Consequently, evaporation residues
produced only by nucleon emission in the deexcitation process of a compound nucleus formed in afusion reaction originate from lowest-spin states of
the compound nucleus. Cross sections of such
residual nuclei are therefore extremely sensitive tothe possible existence of low angular-momentum
cutoff in heavy-ion fusion reactions predicted by
the time-dependent Hartree-Fock (TDHF) calculations. Figure 1 shows examples of such effects
observed in the calculated excitation functions of
the 160( 160, 3p)29AI and 160(15N, 2pn)28AI reactions. The calculation was performed by the evaporation code GROGI II using the level density
parameter a=A/7.5+shell correction and similarvariable moment of inertia as described in Ref. 1.
The shell correction similar to Gilbert andCameron 2) has been used. It has also been assumed
that the low-l cutoff starts to appear at 44 MeV interms of the excitation energy (ECN) of the compound nucleus for the 160+ 16 0 reaction and at 47
MeV for the 160+15N reaction as predicted
theoretically. 3) A value of lower critical angularmomentum (1<) is estimated byindicated by dotted curves in Fig. 1 can be considered as a sensitive signature to probe the possible
effect of the low-l cutoff in fusion reactions.
In order to search for the above effect we havemeasured excitation functions of some evaporation
residues by using r-ray spectroscopy in the reactionsof 15N+ 160, 12C+19F and a+ 27AI as well as in
the reactions of 160+ 16 0 and a+ 28 Si. The measurement was carried out in the same way as
described in Ref. 4. The targets used are LiF, W0 3 ,28Si0 2 (enriched to 99.84%), and metallic AI.
Critical energies estimated theoretically are listed
22$ ~ 29 AI+3P

Eo

(MeV)

31p ~ 28AI+2 pn(1)where f1. is the reduced mass of the system, R the
distance of the two nuclei at the point of contact(R= 1.2 (A 11/3+A 21 / 3) fm), and E~N the criticalexcitation energy. The sudden decrease in yield
E CN (MeV)* Department of Applied Physics, Tokyo Institute ofTechnology.
** Institute for Nuclear Study, University of Tokyo.

Fig. 1. Excitation functions calculated without low-cutoff(solid curves) and with low-l cutoff (dotted curves) for the 32S--+ 29Al+3p and 3lp --+ 28AI+2pn channels.

16

T. Nomura, et al.

Table 1. Critical energies predicted by the TDHF
calculations or classical estimate by Wong. 3 )Projectile
andtarget

QON&)
(MeV)

15N + 16 0
12C+19F

19.81
22.95

a+ 27 Al

9.67

16 0+ 160
a+ 28 Si

16.54
6.95

Eo (MeV)b)

E8N C )
(MeV)

Eqn. (1)

TDHF

27.1
33.2
(B = 8 MeV)
56.4
(B = 12 MeV)

46.9
56.2

28.4

43.5

27

79.4

Q-value for the formation of the compound nucleus.
The critical energy for the low-l cutoff in the c.m.s.
c) The critical energy in terms of excitation energy of thecompound nucleus. ,&)b)in Table 1.
The measured thick target yields in the reactionsof 15N+ 16 0 and 12C+19F are shown in Fig. 2.
The data shown here are normalized on 29AI, which
is produced by 2p emission and shows almost a
constant yield at high excitation energies. Then,the yields of 25Mg and 22N a produced via apn and
2an emission, respectively, are almost the same inboth reactions. The yield of 23N a corresponding to
2a emission in the 15N-induced reactions is larger
than that in the 12C-induced reaction, suggestingthat high spin states are more populated in the
15N + 160 reaction. The yields of 28Al and 27Mg
produced in both reactions respectively by 2pn

. .~
CJ

~o

~10 3

~

Ci

~

~

I

~

:0

0

0

0

29AI+2p

975 (3/ 2+---4 5/2-1 }+390 (3/ 2+---4 1/ 2+)
~

I

::::l

0

and 3pn emission are nearly the same at low excitation energies, but show a significantly large difference at high excitation energies. It is important tonote that this difference begins to appear around
50 MeV, which is close to E8N=47 MeV predictedin the 15N + 160 reaction.
The average product cross sections for 28Al and27Mg estimated from the thick target yields areshown in Fig. 3 together with those in the a+ 27Al
reaction. The cross section for 28AI obtained in the
a-induced reaction is much larger than that in the
HI-induced reaction, presumably due to the significant contribution from the direct reaction like(a, 3He), and therefore cannot be used for comparison. The difference in the yields for 28Al and27Mg between the two heavy-ion reactions may beascribed to the existence of the low-l cutoff in the
15N -induced reaction. In fact, the relative behaviourof the calculated excitation functions shown by solid
curves agrees well with the data on 12C+19F,
although the absolute cross sections are somewhat
larger than the experimental points (we have not
yet tried to optimize model parameters in the statistical calculation). The experimental data of
28Al in the 15N + 16 0 reaction lie between the dashedcurves A and B, which are obtained with the assumption that E2;N= 50 MeV and that 1< is equal to thevalue estimated from Eqn. (1) (A) or to 70% ofthat value (B). The data of 27Mg in the 15N_
induced reaction agree nearly with the calculated
values from the (15N, 3Hep) reaction. This seems

(,

0

0

o·

o·

o ~.

0

0

0

0

0
0

22 Na + 2an
891 (4+---4 3+)

0

27Mg + 3pn
0
o • _

Q)

•
0
o : 12C on 19F

0

~

.s

... . .

I

.:s:;

Q

l-

.
0

·0

0

00

0

: 15N on 16f.......

u

0

.

00 •

10 2

">.

:.c

., ~

0

~

"0
Q)

~

0

0

0

!
~
0

.?
!

0

0

0

0

0

~

Q!
I

0

..
. ...
0

28AI + 2pn

0Q

23Na-t2a"
440 (5/ 2+- 3/ 2+)

21
I

Fig. 2. Thick target yields of some evaporation residues in the 15N + 16 0 (black circles)
and 12C + 19F (open circles) reactions given as a function of EON. The given values are
the measured intensities of r-rays indicated in the figure in units of keY for the nuclei
shown in the left-hand side, while they are estimated from the decay of short-life
activities for the nuclei given in the right-hand side.

17

T. Nomura, et ai.

also consistent with the above assumption because
the (15N, 3pn) reaction is strongly reduced when
the low-l cutoff exists as seen in the figure.
The excitation functions for 29Al measured in the160+ 16 0 and a+ 28 Si reactions turned out to benearly the same up to ECN=50 MeV when the datain the a-induced reaction are multiplied by afactor of ,t2(16 0)j,t2(a). That is, no signature of
the low-l cutoff has been found at 43.5 MeV as
predicted from the TDHF calculation (see Table1). However, the experimental yield of the 16 0_(160, 3p )29Al reaction begins to become considerably smaller than that of the 160(a, 3p)29AI
reaction at higher excitation energies. This difference can be reproduced by the statistical model
calculation if we assume that Eg N = 50 MeV in
the 160-induced reaction and that l< is equal to
70% of the value obtained from Eqn. (1). The comparison with the data on the 20N e+ 12C reaction
is highly desirable.
40

50

60
ECN (MeV)

Fig. 3. The measured excitation functions of 28AI and 27Mg
together with those calculated by the evaporation code
GROGI II. Note that the calculated values are those divided
by a factor of two in the case of 28 Al and by 1.4 in the case of
27Mg. See the text for the meaning of A and B. Note alsothat the given experimental values are those multiplied byl2 (15N)Jl2 (12C) for the case of 12C +19F and by i2 (15N)Ji 2(a)for the case of a + 27 AI.

References
1)
2)

3)

4)

T. Nomura, J. Delaunay, C. Tosello, and N. Bendjaballah: Nucl. Phys. A, 305, 262 (1978).
A. Gilbert and A. G. T. Cameron: Can. J. Phys., 43,
1446 (1965).
P. Bonche, S. E. Koonin, andJ. W. Negele: Phys. Rev. C,
13,1226 (1976); J. W. Negele: Rev. Mod. Phys., 54, 913(1982) and references therein; C.-Y. Wong: Phys. Rev.
C, 25, 1460 (1982).
T. Nomura, H. Kudo, S. Kohmoto, K. Sueki, and T.
Kubo: RlKEN Accel. Progr. Rep., 17, 9 (1983).

18
RIKEN Accel. Progr. Rep. 18 (1984)

111-1-6.

Backward Cross Section in the Generalized Exciton Model
K. Sato

NUCLEAR REACTIONS generalized exciton model, finite][ size effects, backward cross section, 120Sn (p, p') at E p =62 MeV.

The generalized exciton modell) has been extensively applied to give preequilibrium angular
distributions with the help of useful mathematical
reformulation 2),3) which brings much easier handlingof it. Although the model was able to reproduce
global characteristics of the preequilibrium angular
distributions at incident energies of tens of MeV,
it underestimates the angular distribution at backward angles. 4) Former approaches based on it used
the Fermi gas model for target nucleons in evaluating the single nucleon-nucleon scattering kernelG(Q, Q') between a fast nucleon and a target one
which plays a crucial role in determining the angular
distribution. 4) We expect that "the treatment offinite size effects" in the evaluation of the scattering kernel is important to explain the angular distribution at backward angles.
In the present note, we briefly report a study ofthe preequilibrium angular distribution using thescattering kernel along this line in the framework of
the generalized exciton model. We use the single
nucleon-nucleon scattering kernel G(Q, Q') describing the collision process between a fast nucleon
N and bound target ones Nt moving in a harmonic
oscillator potential. On the simplified assumptions
that (I) two nucleons N and Nt interact with eachother via the delta-type interaction and (2) the
scattering can be treated in the plane-wave Born
approximation, we could obtain the scattering
kernel in a tractable form utilizing the analytic
expressions of the cross section. As averaging over
all final nucleon energies discards the importantangle-energy correlation,4) we average over final
nucleon energies only within a small interval ofsmearing width coming from the finite life of theexciton state (uncertainty principle) in which thecollision occurs.
A doubly differential cross section for the emitted
nucleon in the early stages of the reaction can becalculated if we put the eigenvalues PI (1=0, 1,
2, ... ) of the scattering kernel into a simple closedform expression. 3) Considering that our eigenvalues PI are dependent on the energy of the fast
nucleon before and after collision in every single

N-N t scattering, we make the following replacement
m+2-moPI2(I)

in the expansion coefficients (I (m). In Eqn. (I)E in and E out are the incident and the outgoingenergies respectively of the fast nucleon, and E l ,E 2 , • • • are the mean intermediate energies of thefast nucleon after single collision, after double
collision, etc. In a simple case that the emitted
nucleon comes from the m-exciton state after having
lost its initial energy equally in every step of thetotal (m+2-mo}j2 times collisions, the energIes
E j (i= 1, 2, ... (m-mo)/2) take the form

Ej=Ein-ix (Ein-Eout)X m

+i-mo

(2)

We have analyzed the angular distribution forseveral (p, p') reactions with incident energies of
62 MeV. In the calculation, we always put theinitial exciton number mo= 3 and other parameterspeculiar to the exciton model are the same as thosein Ref. 5. The scattering kernel turned out to givethe non-negligible backward contribution increasing with energy loss of the fast nucleon N in collision. In Fig. 1 we compare the calculated angular
distributions with experimental data6) for the reaction 120Sn(p, p'} at E p =62 MeV for three different
outgoing energies. As seen clearly from Fig. 1,
agreement is very good except at small angles;
especially, agreement in the backward angles ismarkedly improved. This result suggests the importance of the treatment of finite size effects in
the generalized exciton model. The discrepancy at
small angles, which is usually the case for every
model, is discussed in Refs. 4 and 7. Our calculated
results for other targets such as 54Fe, 197Au and209Bi show nearly similar fitting with the experimental data, although the overestimation of thecalculated value becomes a little more than the caseof 120Sn target. We have also made calculation using
the assumption that the fast nucleon loses its energy

K. Sato•

120S n (P, p')

Eo"t=. . 30•-

10 0

Ep = 62 MeV

E
xp.dat a
Present
calculation~ 10ot;::O'" ~~~IO Mev~
S\::)I~

~~

10 0

~.

10- 1 L...----'---'-----'-----'---'----"---.Jo 30 60 90 120 150 180
8 (deg.)Fig. 1. Comparison of the calculated angular distributions
with experimental data for the reaction 120Sn (p, p') at Ep=
62 MeV for outgoing energies 30, 40 and 50 MeV. The
solid curves show the calculated results based on Eqns. (1)and (2) with jiw = 41A-l/3 and the smearing width r=10
MeV.

randomly in every step of total (m-mo+2)j2 times
successive collisions instead of Eqn. (2). This
turned out to bring forth only a slight changes ofFig. 1. The decomposition of the cross section at
E out= 30 MeV into contributions from various
exciton states demonstrates that at every angle thereis large contribution from the m= 3 exciton state(one-step process) in contrast with the rapid falling
off of its contribution at backward angles in the
results of the Fermi gas model. At backward angles
both one- and two-step processes account for about
30% of the total cross section respectively and theremaining 40%) comes from the processes of morethan two-step (m>5). The multi-step direct reaction approach proposed by Tamura et al.,7) which

19

made quantum-mechanical treatment of the finite
nucleus, is known to reproduce the preequilibrium
angular distribution very well. In their calculation
the contribution of the two-step cross section
accounts for about 70% (300/0 one-step contribution) of the total one at backward angles for an
27Al target or about 500/0 (50% one-step contribution) for 209Bi at this outgoing energy. Comparing
the present approach based on the generalized
exciton model with those one, we see that the basic
physical picture looks quite different. From thispoint of view, further investigation is necessary to
decide which model is plausible.
In conclusion, the use of the scattering kernel
including finite size effects greatly improves the
backward cross section of preequilibrium nucleon
emission induced by a proton of 62 MeV in theframework of the generalized exciton model. In
the calculation one- and two-step processes dominate
even at backward angles, but those of more than
two-step give considerable contribution. Further
study to refine the present model and to apply it to
the light composite particle emission is desired.
References
1)
2)

3)
4)
5)
6)
7)

G. Mantzouranis, D. Aggasi, and H. A. Weidenmiiller:
Phys. Lett. B, 57, 220 (1975).
S. Yoshida: Proc. IPCR Symp. Macroscopic Feature of
Heavy-Ion Collision and Preequilibrium Process, Hakone,p. 359 (1977).
J. M. Akkermans: Phys. Lett. B, 82, 20 (1977).
A. Iwamoto and K. Harada: Nucl. Phys. A, 419, 472(1984) and references cited therein.
K. Sato, A. Iwamoto, and K. Harada: Phys. Rev. C,28,
1527 (1983).
F. E. Bertrand and R. W. Peele: ibid., 8, 1045 (1973).
T. Tamura, T. Udagawa, and H. Lenske: ibid., 26, 379(1982).

20
RIKEN Accel. Progr. Rep. 18 (1984)

111-1-7.

Classical Trajectory Picture of Massive Transfer
T.lnamura

NUCLEAR REACTIONS maSSlve transfer; average I value][ estimated.

Massive transfer is a type of heavy-ion reactionin which a massive fragment of the projectile istransferred to the target nucleus, and an energetic
light particle such as a proton or an a particle isemitted like a spectator in the forward direction.
We first made a very crude approximation to estimate the average orbital angular momentum <Ii>
in the incident channel. l ) Here the reaction kinematics given by Siemens et a1. 2 ) has been used to estimate <Ii> for the massive-transfer reaction
a+A ~ b+B, B=X+A.
For simplicity, it is assumed that inelastic excitation is negligible in both the incoming and outgoingchannels. Since m A>mX in the present case so thatthe relative velocities VBb~ VAa, the orbital angularmomentum of the spectator particle b is given by

lb= /lBb • Rf .li

(1)

Ri

/lAa

Similarly, the orbital angular momentum of themassive fragment X in the X + A system is given by

lx= /lAX. Rx .h
/lAa

(2)

Ri

Here Ri and R f are the distances between a and A;
Ii is the orbital angular momentum in the incident
channel. These angular-momentum relations havealso been discussed by Ichimura. 3 )The value of Ix should be equal to the averageangular momentum <Jo> transferred to the compound system of X + A. The value of <J0> is
experimentally estimated from the average r multiplicity <M> through the relation(3)<Jo> = <JR>+11J
where <JR> is the average spin of the entry-state
population and we employed the relation <JR> =2 [<M> -4], which is commonly adopted forstatistical treatment of r deexcitation4 ); 11J is theaverage angular momentum carried away byneutrons in the present case. (Empirically, it is
known that a single neutron evaporation carries
away a unit angular momentum on the average.)
Table 1 summarizes information on angularmomenta associated with massive-transfer reactions.
Values of angular momenta except for Lcr andler are experimental ones; the critical angularmomenta for fusion, Lcr and len for 't he X + A
and a + A systems were estimated using a sharp
cutoff formula given by Lefort. 5)
The average orbital angular momentum in theincident channel <Ii> was estimated in such a waythat <li>= <lb>+ <Jo> , where <Jo> wasexperimentally given by Eqn. (3), and <lb> wasreplaced by the classical optimum value given
through Eqn. (1). To estimate <lb>, it was assumed
that li=lcn i.e., Ri=Rcn and that R f is given by thestrong absorption radius. 6)
It is interesting to note that the semi-experimental
quantity <Ii> has turned out to be equal to len
indicating that the assumption li=lcr is reasonable
in terms of Siemens' kinematics. In this classicalmodel, the value of R x , which is estimated from
Eqn. (2) by substitution lx= <Jo> , becomes somewhat smaller than the critical distance for fusion of
X and A.

Table 1. Angular momenta associated with massive transfer: fer and Ler are critical angular momenta for fusion of projectile and target nuclei, and of massive fragment and target nuclei, respectively; <Jo >, which is deduced from the averager multiplicity < M > , the average angular momentum transferred to the compound system of massive fragment and target
nuclei; < Ii > the average orbital angular momentum of the incident channel leading to massive transfer. See text for details.
Reaction
154S m (12C, a4n)158Dy
154S m (12C, a4n)158Dy
159Tb(14N, a3n)166Yb
159Tb(14N, a5n)164Yb
154S m (160, a6n)160Era)

See Ref. 1.

Elab< Ea >

Ler

(MeV)

(n)

<M>

<Jx>
(n)

<Jo <
(n)

< h>
(n)

(n)

85
109
95
115
153

29
46
30
30
45

24
26
24
32
42

12.1
14.7
14.0a)
14.9 a)19.8 a)

16.2
21.4
20.0
21.8
31.6

20
25
23
27
38

40
49
42
50
63

39
47
42
50
63

(MeV)

fer

T.lnamura

21

{oj

( bl

Fig. 1. (a) The instant of massive-transfer reaction a+A -- b+(X+A): A is the target,b the spectator particle, and X the massive fragment. Rb is assumed to be equal to thestrong absorption radius R~nt of the a + A system. Rer and Rx denote critical distancesof the a + A and X + A systems, respectively, where the critical angular momenta aredefined. The dotted circle indicates the most probable position for the massive fragment
X to be transferred. (b) Preequilibrium emission of the light particle b: Rbnt is the strong
absorption radius of the b + A system, and Rb the critical distance of the s~stem.

The above argument enables us to visualize thecollision process characteristic of massive transfer.
Figure l(a) shows the instant of collision leading tomassive transfer, i.e., the spectator particle b to be
emitted at R~nt and the massive fragment X to betransferred at Rx. The dotted circle indicates themost probable position for X to be transferred.
This presentation may be compared to the statement on massive transfer that is based on the
breakup-fusion model?): The breakup fusion takes
place in the deep peripheral region, which is about
2 fm deeper than the usual peripheral region.
For comparison, in Fig. l(b) is illustrated thepre equilibrium light-particle emission process. A
light particle b is at the critical distance for fusionof b and A; and the particle b could be anywhere
within the strong absorption radius Rtnt as well.
In such a case, the collision time should be longer

than in the case (a), and the process should be much
more energy-dissipative.
References
1)
2)
3)

4)

5)
6)

7)

T. Inamura: Proc. Int. School-Seminar of Heavy Ion
Physics, Alushta, USSR, Apr. 14--21, p. 298 (1983).
P. J. Siemens, J. P. Bondorf, D. H. E. Gross, and F.
Dickmann: Phys. Lett. B, 36,24 (1971).
M. Ichimura: Proc. of the Tsukuba Symp. on Heavy Ion
Nuclear Physics, Tsukuba, Japan, Mar. 19-21,p. 179(1981).
D. L. Hillis, J. D. Garrett, O. Christensen, B. Fernandez,
G. B. Hagemann, B. Herskind, B. B. Back, and F.
Folkmann: Nucl. Phys. A, 325, 216 (1979).
M. Lefort and C. Ngo: Ann. Phys., 3, 5 (1978).
J. R. Huizenga: Proc. of Symp. on Macroscopic Featuresof Heavy Ion Collisions, Argonne, ANL/PHY-76-2, p. 1
(1976).
T. Udagawa, D. Price, and T. Tamura: Phys. Lett. B,
118, 45 (1982).

22

RIKEN Accel. Progr. Rep. 18 (1984)

111-1-8.

High Spin States in 110Sn

H. Harada, T. Murakami, H. Tachibanaki, K. Yoshida,
J. Kasagi, and T. Inamura

NUCLEAR REACTIONS 98Mo(l60, 4n), E=76 MeV;][ measured Ep Ip rr( t), a(Ep 0), DSAM; llOSn deduced levels.

The nuclear structure of Sn isotopes has been
extensively studied so far. The constancy of theexcitation energies of 2+ states are well explainedby the generalized seniority scheme and other lowlying l~vels are interpreted as neutron two-quasiparticle states. The proton 2 particle - 2 hole states
are also found to form rotation-like deformed
bands in 112,1l4,1l6,1l8S n .l) For the isotopes with amass number less than 110, however, information
about high spin states is rather scarce.
We have started a systematic study of the nuclear
structure of Sn isotopes with A:::;; 112, using r-ray
spectroscopic technique with the neutron multiplicity filter. 2) Here we report a result on llOSn.
The experiment was performed using the 98Mo(160, 4nr)llOSn reaction at E( 16 0)=76 MeV.
Gamma-ray angular distributions, r-r coincidences
and Doppler shift attenuations were measured incoincidence with neutrons detected with the neutron

multiplicity filter. Identification of r-rays in llOSn
was made mainly by comparison of the yield of
coincidence with more than two neutrons (Mn>2)
to that of coincidence with more than one neutron.
A ratio of these yields is about 0.14 for 4n channels
whereas it is about 0.10 for 3n channels. Figure 1
shows a spectrum which is obtained subtraction of
the spectrum of Mn>l multiplied by a factor of
0.098 from that of Mn>2. As can be seen in the
figure, contributions of r-rays in 3n channels (111Sn
and llOIn) are completely eliminated. In Fig. 1 also
shown is a spectrum obtained in the r-r coincidence
gated by 2+ ~ +0 (1,211 keY), 4+ ~ 2+ (985 keY)
and 6+ ~ 4+ (281 keY) transitions in llOSn.
The 448 keY, 741 keY and 809 keY r-rays are
assigned to those from llOSn in addition to thepreviously reported r-rays.3) We propose a decay
scheme of llOSn as shown in Fig. 2 on the basis of
the r-r coincidence measurement. New r-rays are

6000
..-<

5400
to

4800
Q)

4200

ro

..c:

3600

~

3000

c
c

98Mo (160,471,),) 11 0 Sn neutron multiplicity filter

to

N

~

U"l

00
CJ'l

~
c

::l

0

u

2400
1800
1200
600
00

100 200 300 400 500 600 700 800 900 1000 1100 1200 1300 1400 1500
Channel number

Fig. 1. Gamma-ray spectra obtained in the 98Mo( 160, 4nr)llOSn reaction. Gamma raysfrom llOSn are selected by the neutron multiplicity filter (upper spectrum) and by ther-r coincidence gated by 281 keY (6+ --» 4+), 985 keY (4+ --» 2+) and 1,211 keY (2+ --» 0+)
r-rays (lower spectrum).

H. Harada, et al.

assigned as transitions of a sequence of levels above
8- state at 2,756 keV. These levels can be interpreted
as neutron four-quasi-particle excitations, since
neutron tWo-quasi-particle states cannot give highspin states with ]:r> 9- and 10+.

7

- r -448.2

-

6
>

ClJ

=

5

ClJ

c

LJ.J

(14)

f809.0 (17)ITS7.7 (10)-,.741.5 (26)1174. 6 (18)

::
4

7-

8-

809.0 (27)9-

,1.7 (36 )C
0:; . 31208.5 (66)

...'"

6+
4+

u
x

I.J.J

References
1) J. Bron, W. H. A. Hasselink, A. Van Poelgeest, J. J. A.
Zalmstra, M. J. Uitzinger, H. Verheul, K. Heyde, M.

10 11.3 (IS)
6+

""--

~ 6.0 (20)281.0 (100 )2)

984.6 (100 I

3)

2

.

2+

1211.2 (100)

a

23

0+
110S nFig. 2. Proposed decay scheme of l108n. Numerical figuresin parentheses indicate relative intensities of r-rays observedin the 98Mo( 160, 4nr) 11°8n reaction.

Waroquier, H. Vincx, and P. Van Isacker: Nucl. Phys.
A, 318, 335 (1979).
T. Murakami,' J. Kasagi, H. Harada, and T. Inamura:
RlKEN Accel. Progr. Rep., 17, 125 (1983).
A. Van Poelgeest, J. Bron, W. H. A. Hesselink, K.
Allaart, J. J. A. Zalmstra, M. J. Uitzinger, and H .
Verheul: Nucl. Phys. A, 346, 70 (1980).

24
RIKEN Accel. Progr. Rep. 18 (1984)

111-1-9.

Lifetime Measurement of the 8- State in 110Sn
H. Harada, T. Murakami, H. Tachibanaki, K. Yoshida,
J. Kasagi, and T. Inamura

NUCLEAR REACTIONS 98Mo( 16 0,4n), E=76 MeV;][ measured recoil distance; llOSn deduced T 1/2.

In even tin nuclei, there exist negative parity
states at excitation energies of about 3 MeV. They
are interpreted as neutron two-quasi-particle stateswith (h ll / 2, g7/2) or (h ll / 2, d 5 / 2) configuration. The
8- state which decays to the 6+ state is assigned at
3,770 keV in llOSn.1) Since the E1 transition is notallowed between two-quasi-particle states withneutrons in valence orbits (d 5 / 2, g7/2, h ll / 2, S1/2, andd 3/ 2), this transition gives valuable information on
the configuration of these states.
Recoil distance measurement was carried out inthe 98Mo( 16 0, 4n)llOSn reaction at E( 16 0)=76
MeV, using a device which was used for lifetime
measurement of levels in 49V.2) A self-supporting foil

98 MoC 16 0,4ny)110S n
E

4000

III

= 76 MeV

m

m

>,,>

3000

m
rm

2000

of enriched (95%) 98Mo, 0.95 mgjcm 2 thick wasused as a target and a thick Ta foil served as a recoil
stopper. The relative displacement of the target
and the stopper could be adjusted externally andmeasured by a 1 pm precision micrometer. A Ge(Li)detector was placed at 140 0 to the beam direction.
The measurement was performed with a neutron
multiplicity filter as mentioned in Ref. 3.
Figure 1 shows r-ray spectra obtained for various
stopper distances. Arrows in the figure indicate
positions of stopped and shifted peaks of r-rays
from llOSn. Initial velocity distribution of the recoil
nuclei is estimated under the assumption that neutrons are emitted isotropically in the center of mass
system. The average flight velocity in a vacuum isthen calculated by a Monte Carlo program. Although
the 1,209 ke V r-ray corresponds to the transition
from the 7- state at 3,692 keV, it turned out that a
decay curve of this r ray is determined by the lifetime of the 8- state. Thus, we can obtain the lifetime of the 8- state in good accuracy by analyzing
the 1,209 keY r ray instead of the 1,011 keY r ray.
(The decay scheme of llOSn is shown in Fig. 2 ofRef. 3.)- 1000OJ
C
C

ttl

1209 + 1211

o

.r.
U

D =

';;; 3000
...,

keY

.t:
CJ)

c

g 2000

u

1000

..

4000

"..

a..
o

CJ)

'1211

= 12.0 nsec

'1209 = 1.56 +- 0.30

a..

nsec

o

=

CJ)

3000

/1209 keY

2000
1000

2~00

o
2800

3500

Channel Number

Fig. 1. Gamma-ray spectra obtained in the 98Mo(160,4n)1l0Sn reaction for various stopper distances.

5

10

15

Dl stance (mm)Fig. 2. Plots of the ratio of the yields of the stopped peaks to
the total for the 1,209 and 1,211 keY r rays against stopper
distance.

25

H. Harada, et al.

Figure 2 shows the ratio of the yields of the
stopped peaks to the total for the 1,209 and 1,211
keY doublet. The decay time of the 1,211 keYtransition (2+ ~O+) is known to be 12 ns since it isdetermined by the lifetime of the 6+ state at 2,480
keV.l) A least-squares fit was made with two decay
components as shown in Fig. 2. The lifetime of the
8- state obtained with the average velocity is l.S6±
0.30 ns. The reduced B(M2) value of the transition
between the 8- and 6+ states is therefore 0.23±0.OS
W. D., which is consistent with that of the transition

between the 11/2- and 7/2+ states in 1118n. 4)
References
1)

2)
3)
4)

A. Van Poelgeest, J. Bron, W. H. A. Hesselink, K. Allaart,
J. J. A. Zalrnstra, M. J. Uitzinger, and H. Verheul: Nucl.

Phys. A, 346, 70 (1980).
H. Ohnuma and J. Kasagi: j. Phys. G, 7,1691 (1981).
H. Harada, T. Murakami, H. Tachibanaki, K. Yoshida,
J. Kasagi, and T. Inamura: p. 22 in this report.
R. Brenn, S. K. Bhattacherjee, G. D. Sprouse, and L. E.
Young: Phys. Rev. C, 10, 1414 (1974).

26
RIKEN Accel. Progr. Rep. 18 (1984)

111-1-10.

High-Spin States of Ge Isotopes in the Interacting
Boson Model
N. Yoshida and A. Arima*

NUCLEAR STRUCTURE 66,68,70,72Ge; interacting bOSOn][ model, high-spin states.

Several high-spin bands have been observed in
Ge isotopes. 1),2) They are interpreted as groundstate bands and particle-aligned bands by comparing with the calculations based on various models. 3 ) ,4) The interacting boson model has been
extended so that the aligned bands can be describedby allowing some of the bosons to change into pairsof fermions in the high-j orbitals. 5)
We report a result of calculation, using the extended interacting boson model, of energy levels
and B(E2) values of high-spin states in 66,68,70,72Ge.
Among particles in the orbitals between magic
numbers 28 and 50, we treat the particles in g9/2
as fermions explicitly, and assume that particles inother orbitals are represented well by bosons. The
hamiltonian is

H=HB+HF+ VBF

from quasiparticle energies of g9/2. As the two-bodyinteraction, we assume the surface delta interaction(SDI), and as the boson-fermion interaction VBF,
the quadrupole-quadrupole interaction. The pa68Ge
10
14-

14,
0.019

14,
0.024

1

12+

12
1212

-ro-

1010 --,--

0.041(~~1)~8l0-t- 0.010 0016
0.008 ) ~8 \ 8 + O.0052(!~~)
O~150.015 0. 00003
6 - ' ~vr/

54-

6~

0.020 (5)54-

0.018(5)

2-

3- 4+

where HB is the IBM hamiltonian, HF is the fermion
hamiltonian, and VBF is the interaction between
bosons and fermions. As the IBM hamiltonian, we
take the proton-neutron interacting boson model(P-N IBM, or IBM2) hamiltonian fitted to lowlying states of the same isotopes. The term HF
consists of single-particle energies and two-bodyinteractions. We determine single-particle energies

2-

2-+-

o

2+o-L

EXP

IBM

0.025

Fig. 1. Comparison between calculated (IBM) and experimental (EXP) energy levels and B(E2) values in 68Ge.
Numbers on arrows indicate B(E2) values in units of e2b2 •Experimental data are taken from Refs. 1-3.

~==

o

~=

4-

~=
2-

22-

0-

EXP

14 12 -

12

14-

12-

10_ 12...- (!32..

8 10- 8 8~-8 - (10)5_
8~_
8~6_
4_

~==
2-

64-

~=
2-

6_
4-

14-

14-

1212To-llL

S --.§8-5

10

6=

4_

4==

3-

3-

0-

IBM

~==

2-

2-

0-

0-

0-

20-

IBM

EXP

IBM

EXP

2
2-

Fig. 2. Comparison between calculated (IBM) and experimental (EXP) energy levels in
66,70,72Ge. Experimental data are taken from Refs. 2 and 3.

* Faculty of Science, The University of Tokyo.

0.035

0.D25 (8)

14-

~-

0.037

0...L.

70Ge

~=-

6~

3- 4+

14-

12121010-10888-

I ±.

-8-L~

0.026(!~o)~·02;8(5y

(1)

10

~°To!

N . Yoshida, et ai.

rameters in VBP are varied so as to reproduce theexperimental energies and B(E2) values of highspin states. The hamiltonian is diagonalized in thespace consisting of states with bosons only, stateswith two protons in g9/2 and states with two neutrons in g9/2. As in the case in our previous work,
we do not include fermion pairs coupled to angularmomenta 0 and 2.5) In diagonalization of the hamiltonian, we first diagonalize HB in the boson space,and choose low-energy eigenvectors as boson basis
vectors. They are coupled with fermion pairs toconstruct the basis in the total system where H is
diagonalized.
Figure 1 shows the comparison between calculated
and experimental energy levels and B(E2) values of
68Ge. The calculated B(E2) values are normalized
to experimental values of the transition from 21
to at, although the experimental uncertainty islarge for this transition. The yrast levels are fairly
well reproduced by the calculation. The calculated
location of 10+ in the ground-state band is higher
than that observed, as is often seen in other calculations with rigid cores. 3) ,4) The staggering in ther-band is somewhat exaggerated. The reduction in27

B(E2; 41 -+ 2t) has not been explained by calculations so far. 3),4) Energy levels of other isotopes areshown in Fig. 2; the energy levels are reproduced
well by the calculation. However, the calculated
B(E2) values sometimes considerably deviate fromexperimental values. Especially, calculation often
gives too small B(E2) values for the states of bandcrossing. This feature is common to most calculations of this kind and needs further investigation. 3),4)
References
1)

2)

3)

4)
5)

A. P. de Lima, A. V. Ramayya, J. H. Hamilton, B. Van
Nooijen, R. M. Ronningen, H. Kawakami, P. B. Piercey,
E. de Lima, R. L. Robinson, H. J. Kim, L. K. Peker,
F. A. Rickey, R. Popli, A. J. Caffrey, and J. C. Wells: Phys.
Rev. C, 23, 213 (1981).
N. J. Ward and F. Kearns: Nucl. Data Sheets, 39, 1(1983); F. Kearns: ibid., 33, 481 (1981); F. Kearns andJ. N. Mo: ibid., 25,1 (1978); 31,103 (1980)
A. Petrovici and A. Faessler: Nucl. Phys. A, 395, 44(1983).
K. J. Weeks, C. S. Han, and J. P. Draayer: Nucl. Phys.
A, 371, 19 (1981).
N. Yoshida, A. Arima, and T. Otsuka: Phys. Lett. B, 114,
86 (1982).

28
RIKEN Acce!. Progr. Rep. 18 (1984)

111-1-11.

Ground State Rotational Band In 173Yb Excited by58(
Ni, 58 Ni')
A. Hashizume, T. Inamura, M. Ohshima,* E. Minehara,*
S. Kikuchi,* and H. Kumahora**

NUCLEAR REACTIONS 173Yb (58Ni, 58Ni' r), E= 200 MeV;][ measured Er, I r (0), rr-coin, deduced levels, J, 7r.
The present experiment is one of the series ofstudies on the multiple Coulomb excitations of
nuclei by heavy ions. 1),2) The ground state rotational
states in 173Yb nuclei are built on h 9/ 2-neutron
orbital, i.e., 5/2[512]. We have studied the excitedstates in 167Er; its ground-state rotational band isbuilt on the ir3/2-neutron orbital and a perturbation
effect of rotation on M1 and E2 transitions in theband has been observed. 2) It is our interest to see ifsuch effect can also be observed on the h 9/ 2orbital.
A metallic 173Yb target evaporated on Ta foil
was bombarded with a 200 MeV 58Ni beam from the
20-UR tandem accelerator at Japan Atomic Energy
Research Institute. We measured angular distribu-

tions of deexcitation r-rays and r-r coincidences.
We have also observed Doppler broadened r-raylineshapes. The r-ray singles spectrum was takenwith a Compton suppression spectrometer which
was placed at 0° to the beam. We have not yet obtained the final results from the shape analysis andhave report here the results of r-r coincidence andr-ray angular distributions.
A coincidence spectrum obtained by gating all
peaks of r-ray of intra band transitions are shown in
Fig. 1. An example of angular distribution together
with theoretical analysis by Winther and de Boer
code are shown in Fig. 2. The angular distributionof r-rays in the band are shown in Table 1 together
with mixing ratios. We have established the ground-

173 Ybenl'

Co incidence spectrum
sumed

(j)

s::
s::

ro

.s::

.~

11
s::
~

o

o

Channel/number

Fig. 1. The coincident r-ray spectrum obtained by gating on the peaks of r-rays of intraband transitions.

* Japan Atomic Energy Research Institute, Tokai.
** Department of Physics, Hiroshima University.

29

A. Hashizume, et at.

state rotation band up to the 23/2- state. It is probable from the coincidence results that the 264,
509, and 546 keY transitions belong to the intrabandtransitions and that the 1,736 and 2,018 keY states
are the members of the ground-state band. The
decay scheme is shown in Fig. 3. The states above
610.6 keY (15/2-) were revealed for the first timein the present experiment.

References
1)

2)

T. Inamura, A. Hashizume, M. Ohshima, E. Minehara,
S. Kikuchi, and H. Kumahora:R1KEN Accel. Progr. Rep.
17, 26 (1983),
M. Ohshima, E. Minehara, M. Ishii, T. Inamura, and,A. Hashizume: J. Phys. Soc. Jpn., 52, 2959 (1983).

2018(27/2-)

1736(25/2- )1
1
11471.7(1) Winter & De Boer code
8= - 0.20 ( Q ratio=0.94)

1.4
,1.3

/'"

1.1
1,0-

1001 ,9

j

1.2

3:

1227,1(2) P2. P4 fittingi iiA2 = -0.217±0.017~
A. =-O.023±O.02~A:-f2i-r

1.5,

~

~.

I

I
It

445.7

143.8 MeV (M1+E2)

301.7
179.3
78.5
00

.

I~

I~

.j.

_l

~

13/2
11/2

-

9/r

5/2 (5 171

7/2
sir

J7T

E( keV)---'30-.--4...J.,5-·--6-L- ·- -..L-· - - - . . 1 •
0
90
75
8
The angular distribution of 143.8 keY r-rays.

19/2-

15/2 -

1

~

21/2-

17/2-

1
1

610.6

0.9 0'--.-----"15'-.-

Fig. 2.

1

796.2

231r

Fig. 3. The Coulomb excited states in 173Yb by 58Ni (E=200
MeV).

Table 1. Results of r-ray angular distributions. Mixing ratios are shown in the last column.
Numbers in parentheses are uncertainties.
Level

EL(keV)Er(keV)

A2

A4

Multi.

0

7/29/2-

78.5
179.3
301.7

13/2-

445.7

15/2-

610.6

0.003 (15)-0.057 (20)0.032 (13)
- 0.180 (22)0.035 (12)- 0.217 (17)0.154 (94)
-0:345 (22)0.17 (13)0.009 (16)0.021 (25)-0.016 (15)0.016 (27)0.009 (13)-0.023 (20)-0.03 (11)0.043 (28)-0.04 (19)

Ml+E2
Ml+E2
E2
Ml+E2
E2
Ml+E2
E2
Ml+E2
E2

0.17 (9)0.14 (8)

11/2-

17/2-

796.7

0.244 (12)-0.047 (17)

E2

19/2-

1001.90.218 (32)-0.086 (35)

E2

21/2-

1227.10.220 (26)-0.102 (28)

E2

23/2-

1471.9(25/2)

1736

78.46
100.55179.31122.64223.19143.82266.39164.87308.87185.49350.50205.75391.26225.2
430.92
244.6
469.8
264.3
509

(27/2)

2018546

0.23 (5)E2- 0.10 (8)-0.20 (8)-0.39 (13)30
RIKEN Accel. Progr. Rep. 18 (1984)

111-1-12.

In-Beam r-Ray Study of 218Ra with BGOACS
Y. Ishikawa, Y. Gono, M. Sugawara, and M. Fukuda

NUCLEAR REACTION 20sPb (13C, 3n), E= 70 MeV;]
measured Er, Ir (0), rr-coin, 21SRa deduced levels. 4 sets[of Ge(Li) with BGOACS, enriched target.

Experimental studies of the excited states in
21SRa revealed interesting characteristics of thisnucleus such as: (1) the interleaved spin sequence
4+, 5-, 6+, 7- , ... , 16+, 17- and (2) the large
B(EI)jB(E2) ratios for the deexcitations of thepositive and negative parity states.1) -3) Thesephenomena have been tried to be understood basedon either IBA2) or a-clustering mode1. 3) The samecharacteristics were also found in the neighbouring
nuclei. In the case of 222Th (Ref. 4) the calculation
based on the coupling of the octupole vibration to
the quadrupole deformed core was applied. Experimentally obtained octupole amplitude is somewhat

too large compared with that of the theoreticalestimation.
The experimental results on 21SRa which wereobtained from the experiments made with two Ge(Li) detectors were reported previously. 1) The
experiments were repeated with four sets of the
BGOACS systems. 5) Resulted level scheme is shownin Fig. 1. The negative parity band was extended tothe (21 -) state. In addition, five states were found in
the side band which starts from the (13-) state.
These states were plotted in the ](]+ 1) vs. Ex
plane (see Fig. 2). The band crossing of the negative
parity yrast states can be clearly seen. This phe---r--4440

(21)

C'I)
C'I)

4261

~

t:
~

(19)

4007

(Q

(Q

~

<Xl

3798
(Q

~

(Q

C\t

0
~

3392

('15) :~"!

(14) ~

Q)

\Q

2969

t:

2392 - - - ' 1 - - - . " ' (<Xl+ ~10 · ~

1962 - - - 4 f - - \Q

+ ....

1 547 _8-~-f'f--­---++--1695

"!
~
~

6+ ~

1123 --,.a.~-....

.~-='LL---l 039

....

<Xl
C'I)

~

~

2+
389

\Q
C'I)

~
Q)

co

0 0+

2968
2667

~

+ C'I)
12 ~

+.

3389

~

+ ~
28271_4_-+-_ _ ~4~~~.'O

0

~

'142

3'121

C'I)

218

Ra 130S8

Fig. 1.

Level scheme of 218Ra.

....
~

3588

Y. Ishikawa, et al.

31

200..-------------,
19

5~a.> 150

4~~'~ 100
('\J

7
__~~
0.04
0.06
0.08
(1iw) 2 (MeV2)50~~~~~~~~

o

0.02

Fig. 3. Backbending plot of the negative parity yrast statesin 218Ra.

o

200
300
J (J+ 1)150

Fig. 2. Plots of the excitation energies of states in 218Ra
vs. J (J +1) where J is the spin of the states.

Fig. 2, when the 11J= 1 characters are assumed forthe transitions in the side band.
References1)

nomenon corresponds to the backbending in theplot of the moment of inertia vs. rotational frequency
as shown in Fig. 3. The backbending is known tooccur when the rotational aligned band crosses thecollective rotational band. In the 218Ra nucleus,
two possible aligned bands may be considered tocross the negative parity band, i.e., those of their(ha/2 h9/2) and ])(h5/2 g9/2) orbitals. It may also
be worthwhile to point out that the states in the sideband locate very close to the extension of the line
fitted to the collective negative parity states in

2)

3)

4)

5)

Y. Itoh, Y. Gono, M. Sasagase, T. Kubo, M. Sugawara,
S. Hayashibe, T. Kohno, and T. Nomura: RIKEN Accel.
Progr. R ep., 16, 48 (1982).
J. Fernandez-Niello, H. Puchta, F. Riess, and W. Trautmann: Nucl. Phys. A, 391, 221 (1982).
M. Gai, J. F. Ennis, M. Ruscev, E. C. Schloemer, B.
Shivakumar, S. M. Sterbenz, N. Tsoupas, and D. A.
Bromley: Phys. Rev. Lett., 51, 646 (1983).
D. Ward, G. D. Dracoulis, J. R. Leigh, R. J. Charity,
D. J. Hinde, and J. O. Newton: Nucl. Phys. A, 406, 591(1983).
M. Fukuda, Y. Gono, Y. Ishikawa, M. Sugawara, T.
Inamura, M. Ishihara, T. Nomura, I. Kohno, H. Kamitsubo, J. Kasagi, and T. Murakami: p. 152 in this report.

32
RIKEN Accel. Progr. Rep. 18 (1984)

111-1-13.

In-Beam r-Ray Study of 212pO Using Radioactive
210Pb Target
M. Sugawara, Y. Gono, Y. Ishikawa, and M. Fukuda

NUCLEAR REACTION 210Pb (a, 2n), E=30 MeV, measured][ rr-coin, r( 0), deduced levels, }.

The excited states in 212po were studied by meansof in-beam spectroscopic techniques using theradioactive 210Pb target. A preliminary result was
already reported. 1) Thereafter the experiments
have been made extensively with 30 Me Va-beams.
The measurements performed are:(1) r-r Coincidence with a LEPS (Low Energy
Photon Spectrometer) and two Ge(Li)detectors which were placed at -70°, -132°
and 90° with respect to the beam axis
(2) A r-ray anisotropy obtained from the intensity ratio of those at 90° and 150° withrespect to the beam axis
Figure 1 shows a singles r-ray spectrum takenfrom the 210Pb+a reaction at 30 MeV. In addition
to the known r-rays originated from 212po, relatively intense r-rays were observed. Those stemfrom a Ni-foil which was used as a backing andimpurity materials such as 160, 206Pb and 2osPb,
which were contained in the target. Although there
exists a high background, the r-r coincidence data
provide useful information on the level scheme of
212po (see Fig. 2).
The level scheme of 212po could be extended toan excitation energy of 2,884 ke V based on the
r-r coincidence data. Figure 3 shows the proposedlevel scheme of 212Po. Tentative spin assignments

were made using the angular distribution coefficients, A 2 / Ao, which were deduced from the r-ray
anisotropies. Furthermore, DCO (Directional
Correlation from the Oriented nuclei) ratios werededuced from the coincidence data in order to getcomplimentary information on the spin assignments.
Table 1 lists the angular distribution coefficients andthe DCO ratios of the transitions above the 8+
state. Gamma-rays of 357 and 868 ke V havepositive A2/Ao values and the 577 keY r-ray has anegative A2/Ao value. The spin assignments of the
1,833,2,409 and 2,701 keY levels could not be given
uniquely because of relatively large errors of theA2/Ao values and DCO ratios. However, it may bemost probable that the spin values of these levels are
10, 11 and 12 using the level systematics of the
N= 128 isotones (see Fig. 4).
Three shell model calculations have been madeon the 212PO nucleus. 2)-4) The most realistic one
among them may be of Strottman. 4) Result of his
calculation is shown in Fig. 5. The yrast level sequence is similar to the present experimental result.
Comparing the experimental and theoretical level
schemes, the 2,884 keV level in Fig. 3 seems tocorrespond to the spin 14 state in Fig. 5, but thisassignment does not conform to the known halflife of 45 s of 2,905 ke V isomer because the half-

4.0:;- 3.0
o
><

~ 2.0

z
o

::>

u

1.0

3000
Fig. 1. Singles r-ray spectrum from the 210Pb+a reaction at 30 MeV. r-Rayenergies
indicated in the figure.

M. Sugawara, et al.

Xl02

223

I

6.0

33

357

(A)

I

405

5.0

I

4.0

121

3.0

I

727

I

360

1

r-r Coincidence spectra. The energies of gated r-rays are 577 keY (A), 357 keY(B), and 727, 405, 223 keY (C).

Fig. 2.

(16)45 S( 12.13,14 I
114.2(12.13(1 2 I~
360.3
(11 I
868.3
576.5

(10

2 905
2884
2770
2701
2409

Table 1. Angular distribution coefficients and DCO ratios(intensity r atios at 70° and 132° in coincidence with 223,
405, 727 keY r-rays detected by one G e(Li) placed at 90°)
for the transitions above 8+ level.
Er(keV)1833(81-~- 1752
357.2276.4
1476
121.0
1355
222.8
J 132
404.7

357

577
868

0.07 (8)- 0.41 (8)0.40 (10)1.17 (20)0.85 (25)
1.08 (37)727
72.7.2o
212pO

Fig. 3.

Proposed level scheme of 212PO.

life of the Weisskopf estimate for the 21 keY E2transition is 10- 2 s. However, the level energy of
the isomer was determined based on the a-decay

data which is usually not accurate enough to discusson the energy difference less than 20 keV.
Further experiment is necessary to reach the decisive conclusion on this point.

M. Sugawara, et at.

34!I61 95"s 3485
114)
3304

U!il __

2905(l2 . 13.~~(13102.-,-,,~,,--_~J.lr

(Ill

2409
(W)

00+1

1799

(10)

1833

(~
8~

(8~1

1272

4+

1094

~

0+

14"s 1476
6+
1355

4+

727

o

o

3293

2258

10+ 22"& 1787

8+ 9"s 1625
6+ '
1442

13- 1.6"s 2679
1'-

2335

10+

2026

8+ 1.6"5 1711
6+

(8+)

1763
1562

1508

1193

694

0+

o

688

0+

o

689

0+

o

Level systematics of the N = 128 isotones.

1~=
14!~-

References
1)

1 0 - --

2)
3)
10---

4)
8 _ __
6 -- 4---

2---

0---

Fig. 5.

14+

1132

795

Fig. 4.

3582

9004
2734

/?R4

(12)

16+

~

Shell model calculation by Strottman (Ref. 4).

Y. Gono, Y. hoh, M. Sugawara, and 1. Fujiwara: RIKEN
Accel. Progr. Rep., 17,35 (1983)
N. Auerbach and I. Talmi: Phys. Lett., 10,297 (1964).
N. K. Glendenning and K. Harada: Nucl. Phys., 72,481(1965)
D. Strottman: Phys. Rev. C, 20, 1150 (1979) and references therein.

35
RIKEN Accel. Progr. Rep. 18 (1984)

111-1-14.

Isomeric Transition of 212PO

H. Kudo, T. Nomura, K. Sueki, and M. Magara*

NUCLEAR REACTION 209Bi (a, p) 212mpo, Ea=30-40 MeV,][ isomeric transition, He-jet transport, a-r coincidence.
In 212PO a high spin isomer has been known toexist. 1) An isomeric state in 212PO having a half lifeof 45 s decays primarily to the ground state of 20sPb
by emitting an 11.65 MeV a-particle. The hindrance
factor of this a-decay is very large (4 X 1013), whichindicates that the isomer should be in a high-spinstate. Some shell model calculations predict the
spin-parity of this isomer to be (16+) or (18+).2)-4)
In the calculation by Auerbach and Talmi 2) the
spin-parity is (16+), and in the low-yrast state another possible isomer be in (8+) state. On the other
hand, Glendenning and Harada4) predicted (18+)
state for the 45 s-isomer and (10+) isomeric state in
the low-yrast state. Chulick and N atowitz5) suggested the spin-parity state of the 45 s-isomer as(16+) by DWBA analysis of the angular distributionof this isomer. The lower spin isomeric state of(8+) with a half-life of 14 ns is ascertained recently bysome authors. 6),7) This evidence seems to support
the calculation by Auerbach and Talmi,2) and-__(16+,18+)

I

therefore, the 45 s-isomer is expected to be in 16+
state. The partial level scheme of 212PO is shown in
Fig. 1 taking into account the situations mentioned
above.

>
~~

,

UJE

en=
en(\!
~

0

n.

0

E

~

C\i

>

:E

n.

N

N

>III

Q)

~

:E

N
l!)

2932 4

1~2~_____

55

"I
tOl

('1)1

------t------

measured in this work(arbitrary sequence)

"I
II) 1

C'f)1

-----J-----I
I('II...... 1

U)I
8+
/6+

al

I

I

I

I

121
C'f)

4+

('I

C'\J

(a)

1477
1356 14ns
1133

100r---r--r---r----r---,

II)

0

2+

50

o:t

728

co

('I

"
0+

o

r - - - - . L . - - - _ ; : : : . . 0.3.£l5

a

~~
100

20

40 60 80
TIME (sec)(b)

Fig. 1.

Partial level scheme of 212po.

* Faculty of Science, Tokyo Metropolitan University.

Fig. 2. A part of a-spectra obtained from a-r coincidence
measurement of 212mpo. (a) Singles, (b) 14 to 860 ns delayed
spectrum.

H. Kudo, et ai.

36

100
80
60
ai
c
c
ro
...c

40
20

()
If)

------0

C 100

Accidental

::l
0

()

80
60
40
20

a
0
ChannelFig. 3.

Gamma-ray spectrum obtained from a-r coincidence measurement.

However, there is no direct evidence to assign
the spin-parity of the 45 s-isomer. In this work,
we tried to measure possible r-decay and to assign
the spin-parity of the 45 s-isomer. The ground stateof 212po has a half-life of 0.3 ps and emits an aparticle of 8.784 MeV, which corresponds to the
decay to the ground state of 2osPb. So we applied an
a-r coincidence measurement. The reaction 209Bi_(a, p) was used for the production of the nucleus
212mpo. Ten to thirty pieces of 209Bi targets deposited on thin gold foil were irradiated with 40 MeV
a-particles from the cyclotron and the reaction
products were transported by a helium-jet transportsystem. The transported products were attached ona collecting tape which was moved by a microcomputer controlled pulse motor to the detection position. A Si(Au) detector of 300 mm2 in area and300 pm in thickness and a Ge(Li) detector of a 80
cm3 active volume were mounted at distances of
3 mm and 4 mm, respectively, from the collecting
tape. Coincident signals were stored on a magnetic
tape event by event.
The observed a-spectrum in an a-r coincidence
measurement is shown in Fig. 2, where the 8.784
MeV peak is seen in the delayed spectrum. The

decay curve of this line measured in coincidencewith known r-rays (223 keV, 405 keV, and 728
ke V) is also shown in Fig. 2. A preliminary result in
the a-r coincidence measurement yielded four new
r-rays (129 keV, 357 keV (doublet), and 612 keV)
besides the known transitions below the 8+ state,(see Fig. 3) which yields the branching ratio of theisomeric transition to be 0.070±0.020% • And the
45 s-isomer seems to be in 18+ state, assuming ther-decay is initiated by emitting 129 keV r-ray andconsidering the partial half-life of this r-decay.
References
1)

2)
3)
4)
5)
6)

7)

I. Perlman, F. Asaro, A. Ghiorso, A. Larsh, and R.
Latimer: Phys. Rev., 127, 917 (1962).
N. Auerbach and I. Talmi: Phys. Lett., 10,297 (1964)
N. K. Glendenning: Phys. Rev., 127, 923 (1962).
N. K. Glendenning and K. Harada: Nucl. Phys., 72, 48(1965).
E. T. Chulick and J. B. Natowitz: Nucl. Phys. A, 173,487 (1971).
R. M. Lieder, J. P. D. Didelez, H. Beuscher, D. R.
Haenni, M. Muller-Veggian, A. Neskakis, and C. MayerBoricke: Phys. Rev. Lett., 41, 742 (1978).
P. Lemmertz, L. J. Alquist, R. Fass, H. Wollnik, D.
Hirdes, H. Jungclas, R. Brandt, D. Schardt, and J
Zyliez: Z. Phys. A, 298, 311 (1980).

37

RIKEN Accel. Progr. Rep. 18 (1984)

111-1-15.

Evaporation-Like Products in 14N

+

238U

Reaction

M. Magara, * K. Sueki, H. Nakahara, H. Kudo,
Y. Hamajima,** and 1. Kohno

Elab=]NUCLEAR REACTION 238U(14N, xn) 252-xEs, x=5-7,
80.4--102.8 MeV; He-jet transport, measured a-spectrum, half-life[and excitation function.

The aim of the present work is to understand thereaction mechanism leading to evaporation-likeproducts in heavy-ion induced reactions of heavy
nuclei (less than 10 MeVju). In a heavy reaction
system, the fused nuclei are expected to decay bothby fission and by light-particle emission, but thecompetition between the two decay processes innuclei of high angular momenta is not well understood yet. As a reaction system, we chose 14N +238U
and einsteinium isotopes with mass numbers of 5-7
neutrons smaller than the mass number of thecompound nucleus were investigated.
Light einsteinium isotopes with A<247 havebeen studied by Mikheev et al. 1) and Eskola. 2)
Mikheev et al. first reported in 1967 that by the
238U(14N, xn) reaction 245Es, 246Es, and 247Es weresynthesized; their alpha-particle energies were 7.70,
7.33, and 7.33 MeV, and their half-lives were 1.33,
7.7, and 5.0 min, respectively.
Later in 1972, by the reaction of 241 Am + 12C,
Eskola was able to produce and identify 245- 247Es
which decay by electron capture and a emission.
He reported that the alpha-particle energies of 245Es,
246Es, and 247Es were 7.73, 7.36, and 7.31 MeV,
respectively, and the half-life of 247Es was 4.7 min.
Since there are only a few reports on those isotopes, we first investigated their decay characteristics and then excitation functions.
The target was made by electrodeposition of thepurified uranyl nitrate from the ethanol solution
onto a 2 p.m (3.32 mg/cm 2) Ta foil. The target
thickness was 0.53 mg/cm 2 (U equivalent) which
was smaller than the recoil ranges of the productnuclei (1.4 mg/cm 2 in uranium) so that almost all
the evaporation-like products were expected torecoil out from the target. Beams of 14N ions were
provided from the cyclotron and the beam energies
were varied from 97.6 to 116.2 MeV. When necessary, thin Al absorbers were used to reduce the* Faculty of Science, Tokyo Metropolitan University.
** Faculty of Science, Kanazawa University.

beam energy. Northcliffe's3) range energy curves
were used in the latter case to compute the 14N
energy at the target position. The reaction products
were transferred from the reaction chamber onto amagnetic tape by use of the hdIium-jet transportsystem. 4) The collecting tape was heated at 195 0
for lOs to get rid of the oil that would deteriorate
the resolution of alpha-spectra. For alpha-particle
measurement, we used two Si surface-barrier
detectors placed in sequence along the movementof the tape. The irradiation was performed at aregular cycle of 8 min. The measurement was carriedout for 8 min at the first detector, and then for 8
min at the second detector. The total detection timewas 16 min. This cycle was repeated for about 50
times. Alpha-decay events were recorded together
with external clock pulses and stored on a magnetic
tape in list mode for data analysis.
One example of the observed a-spectra is shownin Fig. 1, in which the 7.3 and 7.73 MeV peaks are

7.31

7.36

++

t

2

7.73

ChannelFig. 1. A part of the alpha-particle spectra observed in repeated bombardment of the 93.1 MeV 14N on a uranium238 target for 82 times. The events observed in channels lessthan 640 are mostly due to Cf isotopes.

38

M. Magara, et al.

101

~100~

p"'-O

P
I

fI'\
P

-

TJ I2= 1.16±0.08min
~

§ 10

If' I

:0-

o

u

-.3
b

10- 1' -

EbB

2

3

4

5

t

-

~

6

Fig. 2. Decay curve of the 7.73 MeV alpha-particle peak of
245Es observed in repeated bombardment of 90.3-93.1 MeV
14N ions. The error bars indicate one standard deviation.

80

90
EJ ab

seen. The energy resolution in terms of FWHM is37 keV. The 7.73 MeV peak was observable only
when the 14N energy was larger than 87.6 MeV andfound to decay with a half-life of 1.16±0.08 min,as shown in Fig. 2. It can be assigned to 245Es inagreement with the published data. The 7.3 MeV
alpha peak was clearly a complex peak and analyzed
into two components from the consideration of its
shape and width. Its intensity of the complex peak
was found to decay with a half-life of 5.40:!=g:~~ minto 5.45:!=g:~~ min when the 14N energy was increased
from 81.5 MeV to 94.0 MeV. Owing to poor
counting statistics, a definite assignment of the twocomponents to 246Es and 247Es was not achieved
yet. A tentative excitation function of 245Es is given
in Fig. 3 and compared with that reported by
Mikheev et al. The cross sections were evaluated on

-

100

110

(MeV)

Fig. 3. Excitation function for the reaction 238U(14N, 7n)245Es plotted vs. 14N energy in the laboratory system.
Filled circles show the results of present experiments andthe solid line is draw through the data points to guide theeye. Open circles show the literature values (Ref. 1).

an assumption that the He-jet transport efficiency
was 700/0 as obtained in previous experiments 5) anddata analysis are in progress.
References
V. L. Mikheev, V. I. Ilyushchnko, and M. B. Miller:
Sov. ]. Nucl. Phys., 5, 3S (1967).
2) P. Eskola: Phys. Rev. C, 7, 280 (1973).
3) L. C. Northcliffe and R. F. Schilling: Nucl. Data Tables,
A7, 233 (1970).
4) H. Kudo, T. Nomura, and J. Fujita: RIKEN Accel.
Progr. Rep., 17, 127 (1983).
5) H. Kudo: private communication.

1)

39
RIKEN Accel. Progr. Rep. 18 (1984)

111-1-16.

High-Lying Single-Proton States of 209Bi Studied by Gamma-Triton
Coincidence Measurement in the 208Pb(a,tyo9Bi Reaction
M. Ishihara, H. Ohsumi, T. Motobayashi, Y. Nagai,* and T. Shimoda**

NUCLEAR REACTION 20SPb(a, t)209Bi at E=60 MeV;]
energy spectra measured at 0= 16° in coincidence with gamma[
rays.

We have been studying single-particle states athigh excitation energies in 209Bi using proton
stripping reactions such as (a, t) and (12C, llB) on
2osPb. Of particular interest is observation ofstrength distributions of proton states of the 6 limregion, which consist of Ij15/2, Ih1/2, 2g 7/ 2, 9/2,
3d3/2, 5/2, and 4S 1/ 2 states and will appear at 2 lim
excitation in 209Bi. Such studies of high-lying single
particle states have been rare so far!) while they arecomplementary to studies of deep-hole states which
exist numerously.
Previous results on differential cross sections in
the 20SPb(a, t)209Bi reaction at 60 MeV2) haveshown that the reaction is useful in populating thosehigh-lying states with appreciable cross sections.
DWBA analyses on the observed angular distributions further indicated that populations of highspin states are dominant in the continuum regionof 4 to 8 MeV excitation, where 50 to 80% of li ll/ 2,
Ij15/2 single-particle strengths were observed. There,
however, remain considerable uncertainties concerning exact spin assignments and magnitudes ofsingle particle strengths. They primarily arise fromambiguities in the estimate of underlying background tail in the continuum energy spectra andalso due to the fact that shapes of angular distributions are too similar among high-spin states toclearly distinguish these states from each other.
Supplemental information is certainly desirable inorder to remove such uncertainties.
To gain additional information on strength distributions, one can think of coincidence measurements with particles or gamma rays which appear
in the decay of excited states of interest. The present
report is concerned with such a measurement inwhich we observed coincidence spectra between
tritons and gamma rays in the (a, t) reaction. The
measurement of gamma rays particularly suits the* Faculty of Science, Osaka University.
** Faculty of Education, Osaka University,case of 209Bi, where neutron and proton separationenergies, Sn and Sp, are 7.8 and 3.8 MeV, respectively. Hence, below 7.8 MeV, gamma transitions
are supposed to be a dominant de-excitation mode
while proton decays will be considerably suppressed
even for Ex>Sp because of the large Coulomb
barrier. The gamma-ray measurement was further
simulated by the expectation that gamma deexcitation of the states at sufficiently high excitation
may primarily occur via EI transitions to low-lying(n-1) lim states. Such Lln= 1 EI transitions will be
unhindered except for the effect of giant resonances
and well overwhelm possible competitions from
Lln=O M1 and collective E3 transitions. If this is
the case, the highly excited initial states of different
spins will selectively decay to particular final statesaccording to spin schemes, e.g., Ij15/2- ~ Ih3/2+'
li ll/ 2+ ~ Ih 9/ 2-, 2g9/ 2+ ~ 2f7/ 2-, etc. Thus one canhope to obtain spin assignments for the initial states
by observing high-energy gamma rays and identifying their final states near the ground state, which
are well separated from each other in the case of
209Bi.
The experiment was performed using a 60 Me V
alpha beam from RCNP cyclotron. Metallic foil of
20sPb with 5.5 mgjcm 2 thickness was used as atarget. Two telescopes consisting of 200 p.m LIE
and 5 mm E silicon detectors were placed at angles
of 0= ± 16° to detect outgoing tritons. They subtended solid angles of 30 msr and covered anangular range of Ll8= ±5.5°. An energy degraderof 1.4 mgjcm 2 Al was placed in front of the telescope to eliminate elastically and inelasticallyscattered alpha particles. Gamma rays were detected with four units of N aI crystal of a size of
6" ifJ X 6". Each of the detectors was located 14 em
apart from the target and had a net photo-peakefficiency of about 2.0% for 1.331 MeV gamma
rays. The coincidence events were treated with a
CAMAC+MBD11+PDPllj45 system and recorded on magnetic tapes.

40

M. Ishihara, et al.

2400

(b)
,-v1.61 MeV

480
1600
Q5

c
c
ro 360
..c

800

U

Vl

2.7 MeV-------

C

(a)

:J
0

u

13/ 2+(1.61MeV)1
20s Pb (a, ty ) 209 Bi
Ea = 60 MeV

240

4.3 Mev
7.3 MeVl120

1, 7/ 2- (0.91MeV),r9/ 2- (0.OMeV)
ChannelFig. 3. Energy spectrum of tritons taken in coincidence withthe 1.61 M eV gamma transition.

ChannelFig. 1. Energy spectra of tritons observed in the 20SPb(a, t)209Bi reaction at Ea = 60 MeV and 0= 16° in singles (a) andin coincidence with gamma rays (b).

20S Pb (a, ty) 209 Bi
Ea = 60 MeV

1600
Q)

c

~ 1200..c

rO.511 - MeV

u2--------

~

800

u

rO.91- MeV (7 / 2 -~ g.s.)
r1.61 - MeV(13/2 +~ g.s.)

400

ChannelFig. 2. Energy spectrum of gamma rays taken in coincidencewith tritons.

Figure 1 compares singles(a) and coincidence(b)triton spectra. Besides intense discrete lines at low
excitation energies, appreciable cross sections areobserved in the continuum region above the particle
thresholds. In the coincidence spectrum, yields forthe region above Sn are strongly suppressed corresponding to opening of a neutron decay mode. On
the other hand, yields for the range of Sp < Ex< Snare enhanced relatively to the lower excitation peaks,
indicating that gamma deexcitation is the main
decay mode for these states as expected. The

enhancement may imply multiplicity of Mr > 1 ofthe deexcitation gamma cascades. The coincidence
spectrum corresponds to a 10 h run for a single
pair of particle and gamma counters and indicatesa promising efficiency of the method used. Figure
2 shows a gamma-ray spectrum taken in coincidencewith whole tritons. The energy spectrum extends
to the region of 8 MeV, indicating the presence ofhigh energy gamma transitions directly feeding
low-lying states near the Fermi surface. Two
prominent lines of 0.91 MeV (f7/ 2- ~ h 9/ 2-) and1.61 MeV (i3/2+ ~ h 9/ 2- ) are present as well as
0.51 MeV annihilation gamma rays. Their intensities are not entirely due to direct excitation of the f7/2
and h3/2 states but partly due to the population fed
from higher states. This situation is indicated inFig. 3, where a triton spectrum in coincidence withthe 1.61 MeV line is shown. Peaks are seen in theregion of E x = 4-8 MeV as well as at Ex= 1.61
MeV. According to the present scenario, thoseyields at high Ex can be related to the strengths ofj5/2 state. Whether the yields are indeed due tosingle-step transitions to the 1.61 MeV state can betested by projecting the events on the Et+Er
coordinate. Detailed evaluation of the data including
such aspects is in progress.
References
1)2)

M. Ishihara: Nucl. Phys. A, 400, 153c (1983); S. Gales, C.
P. Massolo, S. Fortier, E. Gerlic, J. Guillot, E. Rourani,
J. M. Maison, J. P. Schapira, B. Zwieglinski, P . Martin,and V. Comparat: Phys. R ev. Lett., 48,1593 (1982).
E. Takada, M. Ishihara, Y. W. Lui, Y. Mihara, T. Murakami, Y. Toba, and R. E. Tribble: RIKEN Accel. Progr.
Rep., 17, 21 (1983).

41
RIKEN Accel. Progr. Rep. 18 (1984)

111-1-17.

Production and Separation of Neutron-Rich Isotope 15C
Using Heavy-Ion Reactions

K. Asahi, M. Ishihara, T. Shimoda,* T. Fukuda,** N. Ikeda,*** C. Konno,***S. Shimoura,*** K. Katori**, Y. Nojiri,** and T. Minamisono**
NUCLEAR REACTIONS (15N, 15C), E= 119, 158 MeV, (ISO, ]15C), E= 149 MeV; looMo, 2osPb, 232Th targets. Measured E- and[O-distributions. Enriched targets.

The time-like component Ao of the weak axialvector current has attracted special attention1) since
Kubodera et al. pointed out that the two-body part(mesonic exchange correction) is enhanced in Ao.2)
J+ ~ J- (J=O, 1/2) fi-transitions provide a unique
opportunity for such studies, since Ao is shown todominate in the rank-zero matrix element for theseclasses of fi-transition. 3) So far evidence for exchange contributions has been looked for in twocases of the J=O transition.
.
For the case of J = 1/2, in contrast to the J = 0
cases, the transition receives contributions not only
from the rank-zero but also from the rank-one
matrix elements and consequently discrimination
between the two contributions is essential for
extraction of Ao. This can be achieved byobservation of asymmetry 4) in the angular distribution of
fi-rays in reference to the parent nuclear spinpolarization, which would not make sense for J = 0
cases.
The present work thus aims at determination ofan asymmetry factor for fi-decay of 15C (T1/ 2 =2.449 s, Qf3=9.772 MeV). Production of the spinpolarized 15C and preservation of the polarization
for longer than the nuclear lifetime are indispensablefor the experiment. In the present study, heavy-ion
reactions have been chosen as a means to produce
15C for several reasons: (1) light-ion reactions would
be extremely difficult to produce such a neutronrich nucleus unless either radioactive beam ortarget is used; (2) large recoil energies of products
in heavy-ion reactions allow 15C to emerge from athick target and to be implanted in a selected material appropriate for preservation of spin po!ari~a­tion; and (3) a substantial amount of polanz~tlOn
in reaction products can be expected on the baSIS ofrecent observation. 5) It is noted that the use of a

* College of General Education, Osaka University.
** Faculty of Science, Osaka University.
*** Faculty of Science, Kyoto University.

double-D type spectrometer facilitates low-background, high-efficiency collection of neutron-richproducts for the measurement of fi-ray angular
distribution.
To this end we performed a preliminary experiment to examine the production of 15C by heavy-ion
reactions and to explore the feasibility of isotope
separation of neutron-rich products using a spectrometer D UMAS6) developed at Research Center for
Nuclear Physics, Osaka University. Beams of 15N
at 119 MeV and 158 MeV and 18 0 at 149 MeV
were obtained from the AVF cyclotron at RCNP.
Light fragments emitted from the target weredetected by using two sets of .:1E-E SSD telescopes.
Signals from the telescopes were recorded in list
mode on a magnetic tape. The cross section for the
15C production observed for several targets ~x­
hibited broad maximum at angles correspondIng
roughly to the grazing trajectries, as shown in Fig.
1. A simple estimation of f3-ray yields based on thesecross section values revealed that at grazing angles
sufficient statistics for our asymmetry measurement
could be obtained under typical experimental
conditions, provided some 50/0 of polarization is
obtained in the reaction. The yields and energy
spectra of fi-emitting products were investigated toclarify the possibility of isotope separation according
to magnetic rigidity. The result shows that possible
interfering activities, which have Q,e-values larger
than 2 MeV and half-lives in the same range as
15C, can mostly be eliminated through B p selection
provided by DUMAS without losing main part of
15C yield, as demonstrated in Fig. 2.
In conclusion, we have found that the present
method is useful for the detailed study of fi-decay
and nuclear structures of neutron-rich isotopes suchas 15C. Development of the experimental setup
along these lines is now under way. The present
work also has a particular implication in future
experiments which will become possible by using

42

K. Asahi, et aZ.

o lOOMo

\

10

\ .
\\

·;c Production

0.1

0.01

•

Pb

A

232Th

2
.'A 32o looMo
Pb
Th

~

.
0.1

15C Production

0.01 L-....l---L_L-....l-----l.._L-.....I.-----I..--l

40

60

80

o

20

40

60

01. (deg.)OL (deg.)

(a)

(b)

80

80

Fig. 1. Angular distributions of 15C in the reactions induced by (a) 15N at 119 MeV, (b)15N at 158 MeV, and (c) ISO at 149 MeV on the 10oMo (open circles), 20sPb (closed
circles), and 232Th (triangles) targets.

800

600
400

15N+ Pb£1.= 158 MeV
81.= 30·

200

the new RIKEN accelerator, since the method usedhere is expected to be extremely powerful whenapplied to the high-intensity, uniform-velocity
fragments obtained in intermediate energy heavyion reactions.
References
C. A. Gagliardi, G. T. Garvey, J. R. Wrobel, and S. J.
Freedman: Phys. Rev. Lett., 48,914 (1982); T. Minamisono, K. Takeyama, T. Ishigai, H. Takeshima, Y. Nojiri,
and K. Asahi: Phys. Lett. B, 130, 1 (1983).
2) K. Kubodera, J. Delorme, and M. Rho: Phys. Rev. Lett.,
40, 755 (1978).
3) E. K. Warburton, D. E. Alburger, and D. J. Millener:
Phys. Rev. C, 29, 2281 (1984).
4) M. Morita: Beta Decay and Muon Capture, W. A.
Benjamin Inc., Reading, Massachusetts, p. 173 (1973).
5) K. Asahi, M. Ishihara, H. Kamitsubo, N. Takahashi, Y.
Nojiri, T. Minamisono, A. Mizobuchi, and K. Sugimoto:Nucl. Instrum. Methods, 220, 389 (1984).
6) T. Nora, M. Nakamura, H. Sakaguchi, H. Sakamoto, H.
Ogawa, M. Yosoi, T. Ichihara, N. Isshiki, M. Ieiri, S.
Kobayashi, and H. Ikegami: RCNP Ann. Rep., 1982,
189 (1983).
1)

8k
4k

Fig. 2. Schematic illustration of isotope separation using
DUMAS, according to the magnetic rigidity Bp. Bp spectra
are shown for the ,B-emitting products with half-lives ranging
from 0.1 s to 100 s. Shaded area represents a possible Bp
window chosen to have largest 15C yield and lowest background contributions.

43

RIKEN Acce1. Progr. Rep. 18 (1984)

111-2.

Atomic and Solid-State Physics

1.

Classical Trajectory Monte Carlo Calculation for Collision
Processes of e+ (e-p) and p+ (p-p)++

A. Ohsaki, T. Watanabe, K. Nakanishi,* and K. Iguchi*

The classical trajectory Monte Carlo (CTMC)
method is applied to the pick-up process A+(BC)-+ (AB)+ C of a bound light particle by an incident
light particle as well as the breakup process A +(BC) -+ A+B+C. The calculation has been performed for the cross sections of the processes in thecases of A=e+ and p+, B=e- and =p-, and C=p.
The three-body problems can always be solved
numerically, if we treat them by classical mechanics.
An application of classical mechanics, called a classical trajectory Monte Carlo (CTMC) method, hasbeen successful and has been proved to give proper
cross sections.1),2) The CTMC is a method in which
the three-particle motion is solved by Hamilton's
canonical equations and the initial quantum states
are set statistically using random numbers. The
actual physical reason to provide proper cross sections has not been made lucid yet.
In this paper, we calculate the cross sections ofe++(e-p) -+ (e+e-)+p(1)-+ e++e-+p(2)p ++(p-p) -+ (p+p-)+p(3)-+ p++p-+p

(4)

and

by using the CTMC method. These processes causea large momentum change between the prior andpost channels because the centers of masses ofcomposite particles are largely moved in Processes(1) and (3). For Process (3) the lifetimes of (p+ p-)
are considered 7 X 10-10s in the triplet state and
6 X 10-13s in the singlet state. By comparing thecharacteristic time of Is orbital of (p+ p-), i.e., ofth~ order of 10-19s with the collision time of 1 ke V
impact, i.e., of the order of 10-17s, the final state of(p+ p-) and the collision Process (3) are definedsafely.
Comparison with other quantum mechanicalcalculations3)-8) for Processes (1) and (2) and also

* Department of Chemistry, Waseda University.

comparison with recent quantum mechanical calculation9) are made and the physical argument for the
calculation are also given. The cross sections for
positronium formation agree with those obtainedby recent quantum mechanical calculations except
for low impact velocities. The cross sections for(p+ p-) formation are smaller by about 30% in
magnitude than those by the quantum mechanicalcalculations, the first-order Born approximationand the first-order distorted-wave Born approximation. As for practical purpose, there has beensome discussion on the feasibility to obtain (p+ p-).lO)
If it is successful, this will be much useful for theinvestigation of quantum electrodynamics. As oneof the possible ways to obtain (p +p-), Process (3)is of great interest.
The energy difference between the initial (ground)state and the final (Is) state in Process (1) is 6.80
eV and the threshold energy of Process (2) is 13.6
eV. Processes (1) and (2) are endothermic. Results ofcalculation for Processes (1) and (2) are shown in
Fig. 1. Comparisons with the quantum mechanicalcalculation are also given there. The CTMC transfer(Process (1) ) cross section is a little larger than thoseby the quantum mechanical calculation except in
the energy region less than 25 eV. The general velocity dependence of (J above 30 eV by CTMC is similar
to that by the quantum mechanical calculation.
The decreasing behavior of transfer cross section
is determined by the same physical reason as incharge transfer, i.e., the momentum overlap of the
wave functions between the initial and the final
bound states. The cross section for breakup process(Process (2») can be compared with that by thequantum mechanical calculation.
The energy difference in the bound state levels
between the initial (ground) state and the final (Is)state in Process (3) is 1.12 ke V and threshold energyof Process (4) is 2.52 keY. Both processes (3) and(4) are given in Fig. 2. Comparisons with the recent
results by the first-order Born approximation (FBA)
and the first-order distorted-wave Born approximation (DWBA)9) are also given in Fig. 2. The CTMC

A. Ohsaki, et ai.

Breal< UP

~

c

~

o

c

:iJ

o

()

Q)
(f)
(f)
(f)

:p

10-1

as 10- 5

(f)

o

(f)
(f)

L-

o

\

o

L-

o

Transfer(Total)\\\\,y./B.K.
\

\

\
\

Threshold of positronlum
formation

Transfer threshold

\

\

\

\

\

lionization threshold
10-3~

o

_ _J....-...l.-_ _ _-+-___-;I;--_ _ _----;
1

2

3

1O-7L_~~1-

4oPositron velocity (a.u.lFig. 1. Positronium formation (transfer, e++H --(e+e-)+p)
and breakup (ionization, e++H -- e++e-+p) cross sections
as functions of impact velocity.
Transfer cross section;- 0 - : CTMC calculation (present result),- 0 - : Partial wave+modified Born approximation by
Drachman, McGuire and Omidvar (Ref. 6),- \ 1 - : First-order Born approximation (Ref. 6),- /). - : Distorted-wave Born approximation without double
collision process by Mandel, Guha and Sil (Ref. 4),-e-: Distorted-wave Born approximation with double
collision process by Shakeshaft and Wadehra (Ref.
5),......... : Brinkman-Kramers method calculation (present
result).
Ionization cross section;- 0 - : CTMC calculation (present result),- - - : Quantum mechanical calculation (Ref. 7).

result is somewhat smaller than those of FBA and
DWBA. This feature is different from the positronium formation. In the case of positronium
formation, the result by FBA is still smaller thanthat by CTMC. The rapid decrease in the transfer
cross section with impact velocity is due to thesame physical reason as that in the cases of positronium formation and charge transfer in ion-atomcollision. The breakup cross section can be scaledwith that of positron impact.

_ _ _±-__---lJ';;--_ _

\

\

~

4

Fig. 2. (p.+fr) formation (transfer, p.++(p.-p) -- (p.+p.-)+p)
and breakup (p.+ + (p.-p) -- P+ + I.r+P) cross sections asfunctions of impact velocity.
Transfer cross section;- 0 - : CTMC calculation (present result),- \1-: First-order Born approximation (Ref. 9),- /). - : The first-order distorted-wave Born approximationby Ma et ai. (Ref. 9),......... : Brinkman-Kramers method calculation (present
result).
Breakup cross section;- 0 - : CTMC calculation (present result).

References

3)
4)

R. E. Olson and A. Salop: Phys. Rev. A, 16, 531 (1977).
M. Karplus, R. N. Porter, and R. D. Sharma:]. Chem.
Phys., 43, 3259 (1965).
A. Rich: Rev. Mod. Phys., 53, 127 (1981).
P. Mandel, S. Guha, and N. C. Sil:}. Phys. B, 12, 2913

5)

R. Shakeshaft and J. M. Wadehra: Phys. Rev. A, 22, 968

1)
2)(1979).

6)
7)
8)
9)
10)

(1980).
R. J. Drachman, K. Omidvar, and J. H. McGuire: ibid.,
14, 100 (1976).
L. J. Kieffer: At. Data Nucl. Data Tables, 1, 19, 120(1969).
P. W. Bussard, R. Ramuty, and R. J. Drachmann:
Astrophys. }., 228, 928 (1979).
Q. Ma, X. Chang, Z. Liu, Y. Liuand, and T. Watanabe:
Phys. Rev., submitted.
K. Nagamine: Proc. IIIrd LAMPF II Workshops, (eds.
J. C. Allred, T. S. Bhatia, K. Rumminer, and B. Talley),
LA-9933-C, p. 258 (1983).

45
RIKEN Accel. Progr. Rep. 18 (1984)

111-2-2.

Quantum Mechanical Study of the Process p+ + (p-p)~Cu+p-) +p
Q. Ma,* X. Cheng,* Z. Liu,* Y. Liu,* and T. Watanabe

On the occasion when one of the research staff(T. W.) of RIKEN visited Chinese University of
Science and Technology (CUST), the theoreticalphysics group in CUST and the Atomic Physics
Laboratory in RIKEN have agreed to make collaborative work in the field of theoretical atomic physics
and also in related academic fields. As one ofpractical projects, we chose the scattering problem
of p+ on (p-p). This process has been suggested by
Nagamine 1) as one of the possible ways to produce(p+p-) atoms from an experimental point of view.
The atomic structures of exotic particles draw
much attention from the viewpoint of quantum
electrodynamics (QED). They will give us muchinformation concerning QED because the p+ pconsists of structureless elementary particles(leptons) and the heavy masses of p+ and p- enhancevarious important phenomena related to QED, suchas vacuum polarization, Lamb shift, etc. As one ofthe possible ways to produce (p+ p-), one canconsider the process(1)

Here we are formulating and calculating the crosssections for Process (1) by using a quantum mechanical way. Process (1) is characterized by the large
mass transfer between the initial and final states andconsequently the center of mass of the incident
particle is greatly varied. Furthermore, there exists
a large endothermic energy difference (1.13 ke V)
between the initial and final states. In this sense,
this is considered to be a typical three-body collision
problem. Process (1) has also been investigated byusing the classical trajectory Monte Carlo (CTMC)
method. 2) The CTM C method treats a three-bodyproblem rigorously in classical mechanics. We canobtain the characteristic features of the three-bodyproblem in the limit of classical mechanics. On theother hand, the quantum mechanical method may
show the characteristic features of quantum mechanics. For this reason, if we can obtain similar results
for the same process by the first Born approximation
or by some improved approximation to those by
CTMC, the cross section can be considered reliable.
The first-order Born approximation (FBA)* Department of Modern Physics, Chinese University of
Science and Technology.

and the first-order distorted-wave approximation(DWBA)3) have been applied to Process (1). Using
the coordinate system illustrated in Fig. 1, thetotal Hamiltonian of the system can be written as

h2
h2
e2
H=- -Zp VR 2- -Zl.I Vr 2--+H·'
(r R)
r
l'
-+

-+

and
Ii, 2
Ii, 2
e2
-+
-+
H = - -Z ' VR,2_ - ' Vr,2- - , +Hr' (r', R')
ZlJ
pr

where p and p' are reduced masses of the relative
motion in the initial and the final states, and lJ andlJ' are reduced masses of a composite atom in theinitial and the final states, respectively. H/ (;, R) andHe' (?, R') are the interaction Hamiltonians in theinitial and the final state.
We approximate the total wave function of thecolliding system as

where ¢re;) and ¢/;) are the ground state eigenfunction of composite particles in the initial and thefinal state and Fi(R) and Fr(R') the corresponding
wave functions of the relative motion.
The equations for Fr(R') in FBA and in DWBA
are given as(- :;, VR,2+ cr-E )FrFBA(R')+ <¢r(r')IH/IFiO(R)¢i(r»r'=O
where FiO(R) is a plane wave in the initial state,and(- z~, VR,2+ cr- E )FrDW(R')+<¢r(;')I(-1; VR 2+c i-E)I. Fpw(R)¢lr»r'+ <¢r(;')IH'iIFiO(R)¢<!»r'=O
From these FrFBA(R') and FrDW(R'), the scattering
amplitude f( 0) and the total cross section with thisf (0) can be obtained as(]=~; ~ If(0)1 2d!)

Q. Ma, et al.

46

Table 1.
(p.-p).

oFig. 1.

Coordinate system of colliding particles.

)..1 + + ()..I- O) --> ()..I + )..1- ) +0\

\ \ _____ DWBA

\ .._____ FBA
\

.",

\

\\

~ 10- 5
(f)
(f)

o
L-

o

I

\

""\\~
\

o

\

'\

"

4=i

\~ B.I<.

\[!),-.~ ';o......

c
o

\

\
\

\

'\\
\ ,\ \
\ \

\
\
\
\
\

~\

/ \\
CTMC

\

'\\
. I
\

(n = 1)

\

\

\

\
\

\

\\

\

'

\, I

\

\

\ I
, I

\

2.\1
'

, I

\ ~

\b
\
\

\.

(p.+ p-) formation cross sections by p.+ impact on

Impact energyof p.+

FBA
cross section

DWBA
cross section

1.13 (keV)
1.20
1.70
2.00
2.40
3.60
7.00
20.00
100.001,000.00

1.29 E-l0 (it'ao 2)
2.44 E-05
1.62 E-04
1.77 E-04
1.67 E-04
1.05 E-04
2.54 E-05
7.51 E-07
3.48 E-l0
7.47 E-16

1.47 E-l0 (it'ao2)
4.80 E-05
1.79 E-04
1.89 E-04
1.75 E-04
1.09 E-04
2.79 E-05
9.76 E-07
6.02 E-l0
1.16 E-15

where Vi and Vf are the velocities of the initial andfinal states, respectively.
Figure 2 and Table 1 show the results of calculation: the cross section for Process (1) as a functionof impact velocity in FBA and in DWBA. Thisshows that the DWBA result is not so muchdifferent from the FBA result and these are 30-500/0
larger than the CTMC results in the impact velocity
region of 1.75-3.0 a.u. The BK (BrinkmanKramers) result is about five times larger than
FBA. The CTM C results are considered more reliable than those of FBA and DWBA in the velocity
region below 1.7 a.u. From these results we canconclude that the maximum of the cross section
lies around 1. a.u. impact velocity (2.0-3.0 keY
impact energy) and its magnitude is 3.5-5.0 X 10- 4
ao 2 (ao being the hydrogen Bohr radius) or 2.74.0 X 10-20 cm 2 •References

10- 7O~~~~1--~--~2--~---+3--~--~4

Impact velocity (a.u.lFig. 2. (p+ p-) formation cross section by p.+ collision on(p.- p) as a function of impact velocity. - - : the first-order
Born approximation (FBA), ...... : the first-order distortedwave Born approximation (DWBA), _. -.6,_.-: classical trajectory Monte Carlo method (Ref. 2).

1)

K. Nagamine: Proc. IIIrd LAMPF II Workshop, (eds.

J. C. Allred, T. S. Bhatia, K. Ruminer, and B. Talley),2)
3)LA-9933-C, p. 258 (1983).
A. Ohsaki, T. Watanabe, K. Nakanishi, and K. Iguchi:
p. 43 in this report.
P. MandaI and S. Guha: J. Phys. B, 12, 1603 (1970).
FBA and DWBA calculation for e++H---+(e-e+) + p

47
RIKEN Acce1. Progr. Rep. 18 (1984)

111-2-3.

Transitions of Molecules between High-Angular-Momentum States
I. Shimamura and A. C. Roy

The secondary electrons produced by highenergy charged particles or by ionizing radiation
lose their energies, as they penetrate matter, by
exciting atoms or molecules. When the energies ofthe secondary electrons become low (~ a few eV),the main energy-loss mechanism is the rotational
excitation of molecules.
The cross section for electron-impact excitationof a molecule from a well-defined rotational state
to a well-defined rotational state is difficult to measure directly. This is due to the small rotationallevelspacings; an electron spectrometer with extremely
good energy resolution is required for resolving therotational lines in the electron energy-loss spectra.
On the other hand, reliable theoretical calculationsof the cro,ss sections are usually cumbersome.
Molecules in gas at thermal equilibrium are normally distributed among many high rotational states
because of small rotational energies. Therefore,transitions from many different rotational states
to many different rotational states are taking placein the gas. Calculations of the cross sections for allof these transitions are almost impossible, if separately carried out. Simple relations exist, however,between the cross sections for different transitions~
J] of linear molecules between highangular-momentum states. 1),2) A virtue of these
relations is that they express the cross sections forthe transitions with a fixed J] and with any high] in terms of a single unknown parameter independent of]. We have made an attempt to generalize these relations for symmetric-top molecules,
and have reported some results for special cases in
the preceding issue of this report. 3) The following
presents the most general results on molecules
regarded as symmetric-top rotators.
Symmetric-top rotators are those rigid bodies
which have two equal principal moments of inertia.
The good quantum numbers of symmetric tops are] for the magnitude of the rotational angular momentum and K and M (-]~K~], -]~M~])
for its projections onto the body-fixed symmetry
axis and onto a space-fixed quantization axis.
Because the rotational levels are degenerate in M,
one may conveniently define the electron-impact
excitation cross section da(]K ~ ]'K')/dm averaged
over the initial M and summed over the final M.

] ]+Except in very slow collisions (E:S102 meV) the
molecules hardly rotate during the collision, because
the rotational periods of the molecules are much. longer than the collision time. Therefore, we may
safely employ the adiabatic approximation in which
the orientation of the molecular axes is assumed
to be fixed during the collision.
The main result obtained in the adiabatic approximation with no furth_~r_t!pproximations is thatda(]K ~ ]±J], K+JK)/dm=A(IJ]I, JK) [1±(J]/2]){l+(K'2_K2)B(IJ]I, JK)}+O(]-2)](1)

with K'=K+JK. Both A(IJ]I, JK) and B(IJ]I,JK) are independent of ] and K, and are expressible as linear combinations of the cross sectionsfor ]=K=O. The two quantities A and B may be
calculated theoretically, or may be treated as unknown parameters in analyzing experimental data.
Normally, the cross sections are appreciable only
for small values of IJ]I and IJKI, say, smaller than
5 or so. This means that only a small number of
independent dynamical quantities determine all
the rotational cross sections that play an importantpart in the energy loss by electrons in a moleculargas. As the initial] becomes large, the cross sections(1) for the +J] and the -J] transitions approacha common limit in a symmetrical way, one fromabove and the other from below.
In some special cases Eqn. (1) takes even simpler
forms:
da(]K ~ ]±J], K')/dm=A(IJ]I, JK) [1±(J]/2])+O(]-2)](2)

for IKI=IK'I, andda(]K ~ ]K')/dw=A(O, JK) [1+0(]-2)](3)

for J]=O. If the rotator has a plane of symmetry,
A and B in Eqn. (1) are independent of the sign of
JK.
The results reported here are applicable not only
to electron-molecule collisions but also to positronmolecule, atom-molecule, and ion-molecule collisions and to photoabsorption and photoionizationof molecules, all in the adiabatic approximation.
Equations (1)-(3) are useful also in analyzing rota-

1. Shimamura, et al.

48

tionally unresolved energy-loss spectra of electrons
to extract state-to-state rotational transition crosssections. 4)3)4)

References
1)2)

1. Shimamura: Phys. Rev. A, 28, 1357 (1983).
1. Shimamura: Chapter II in Electron-Molecule Colli~

sions, (eds. 1. Shimamura and K. Takayanagi), Plenum
Press, New York p. 89 (1984).
1. Shimamura and A. C. Roy: RIKEN Accel. Progr. Rep.,
17, 44 (1983).
1. Shimamura: in Wavefunctions and Mechanisms from
Electron Scattering Processes, (eds. F. A. Gianturco and
G. Stefani), Springer-Verlag, Berlin p. 210 (1984).

49
RIKEN Accel. Progr. Rep. 18 (1984)

111-2-4.

Theoretical Investigation of Molecular Photoionization
S. HaraPhotoionization of molecules · is one of the mostfundamental problems in the study of interactionof radiation with matter. In this report, photoionization of H2 is theoretically investigated.
In the present calculation, the final e+ H2 +scattering state has been obtained by taking into
account the adiabatic interaction between an
electron in the continuum state (photoelectron)
and a deformed molecular ion, i.e., by the static
exchange approximation with the adiabatic dipole
polarization potential added.
The angular distribution of the photoelectron for
the transition

H 2(X 1 l: gV" =0, J")+hlJ ~ H2+(X 2 l: gV ', J')+ej3v'= ( Z.0+j302 -(J02 )/( 1.0+a02
-)
aoo
aoo

Equation (4') gives a correct value for the photoionization of H2 by 584 A line, since the cross section for 11J24 is at most 0.3%) of that for 11J =0. 4)
We now turn to the discussion how we obtainthe values of j3v' from the experimental data of
Pollard et aI.3) and Ruf et aI.4) They measured theintensity ratios of the Q and S rotational branches
at several angles including 54.7° by using unpolarized radiation. Angular distributions for · the Q andS branches in their experiments is given by

Q
IQ(O')= 4~ (JQ[ 1- j32 P2(coshas the form 1),2)
1

I.o"Jvr(O)= 4rr (Jv"J"v'J{1+{3v"rv'rP2(cosO)](1)= L;C(J"jJ'; 000)2 IOj(O)

(2)

j

0')]

1

Is(O') = 4rr (Js[1- 13; P2(COSO')]
where
aQ= L;grarp)
J"

where 0 is the angle of an ejected electron measured
from the direction of photon-polarization, av"J"v'J'
and /3 v" J"v'J' are the total cross section and asymmetry
parameter for the above-mentioned process, J" andJ' are the rotational quantum numbers, and C(J'jJ' ;000) is th~ Clebsch-Gordan coefficient. The vibrational quantum numbers V" and v' are omitted in
Eqn. (2) and hereafter. From Eqn. (2), we obtain(4')

aQj3Q= L;grarJ'/3J"J'J"

as= L;grarr+2, (Js{3s= L;grarJ"+2/3rr+2 (5)J"J"

and 0' is the angle between incident radiation andan ejected electron. They used H2 molecule inwhich ortho-para ratio is 3: 1 at very low temperatures (77°K and 1400K). Therefore, for theirexperiments,

gO= 1/4, gl =3/4,

gr=O (J">2)(6)

Substitution of Eqns. (3) and (6) into Eqn. (5) gives

aJ"J'= L;C(J'jJ'; 000)2 aOj
j(JrJ'/3rJ' = L;C(J''jJ'; 000)2(JJ"J'j3rJ'(3)jVibrationally resolved cross section (Jv, and asymmetry parameter /3v' are given by3(JQ=(Joo+1O(Jo2(3Q= (Z.O+ 1301302 :~~)/(1+130 :~~)

7(Js = 1O(Jo2,/3s= /302

The ratio of the Q and S branches, R(O')= Is(O')/
I Q(0') at 0' = 54.7°, determines the ratio (J02/ (Joo

L;grC(J''jJ'; 000) 2a Oj
jrJ'= 2:(JOh=j(Jv,j3v'= 2: (JOjj3 OJ(4)jwhere gr is the initial rotational distribution with
L;gr= 1. If the energy of the ejected electron is~~t so high and the cross section for 11J= J' - J" 2 4
may be neglected, Eqn. (4)(5')

R(54.7°)=Is(54.7°)/IQ(54.7°)= ~ (J02/{(1+_ 3_ (J02)
10 (Joo
10 (Joo
The measurement of R( 0') at another angle determines /302 since (302 is only one unknown parameterleft in R( 0'). The asymmetry parameter /3v' canthen be obtained from Eqn. (4').

50

S. HaraTable 1.

The ratio (J02/(JOO, f302 and f3v' for 584 A line.

v'(J02/(JOOo(a) 0.241(b) 0.127(c) 0.103(d) 0.131 (4)(e) 0.143 (5)(b) 0.0956(c) 0.0853(d) 0.107 (3)(a) 0.159(b) 0.0759(c) 0.0713(d) 0.088 (2)(b) 0.0620(c) 0.0591(d) 0.075 (2)(b) 0.0514(c) 0.0500(d) 0.062 (2)(b) 0.0435(c) 0.0438(d) 0.054 (2)

2

3

4

5

f302

0.749
0.2
0.831
0.87 (12)0.89 (15)0.2
0.782
0.75 (11)
0.687
0.2
0,746
0.75 (11)0.2
0.723
0.83 (11)0.2
0.702
0.69 (13)0.2
0.680
0.68 (14)

f3v'

1.758
1.797
1.891
1.868 (14)1.862 (19)
1.843
1.904
1.878 (11)
1.820
1.873
1.917
1.899 (9)
1.895
1.929
1.918 (8)
1.912
1.938
1.923 (8)
1.925
1.945
1.933 (8)(a) Itikawa,7) 1= 1,3; (b) Itikawa et al.,8) 1= 1; (c) Present,
1= 1, 3; (d) Deduced from the data of Ruf et al.,4); (e)Deduced from the data of Pollard et al. 3 ) Numbers inparentheses are standard deviations. (l is the angularmomentum of ejected electron.)

In Table 1, the ratio a02/aoo, ~02, and ~v, thus
deduced from the experimental data are tabulated.
The asymmetry parameters ~v, for small v' areconsiderably larger than the values obtained bymeans of relative intensity measurement at several
angles.5) ,6) These values are not tabulated. The
present results are considered to be reliable morethan those of the above experiments since corrections for the reaction volume are not necessary.
Table 1 also includes the present and other theoretical values.
References
1)

2)
3)
4)
5)
6)

7)
8)

A. D. Buckingham, B. J. Orr, and J. M. Sichel: Philos.
Trans. R. Soc. London, S er. A, 268, 147 (1970).
J. M. Sichel: Mol. Phys., 18,95 (1970).
J. E. Pollard, D. J. Trevor, J. E. Reutt, Y. T. Lee, and
D. A. Shirley: Chem. Phys. Lett., 88, 434 (1982).
M-W. Ruf, T. Brege!, and H. Hotop: J. Phys. B, 16,
1549 (1983).
J. Kreile and A. Schweig: J. Electron Spectrosc. Relat.
Phenom., 20, 191 (1980).
E. D. Poliakoff, J. L. Dehmer, P. M. Dehmer, and A. C.
Parr: Chem. Phys. Lett., 96, 52 (1983).
Y. Itikawa: Chem. Phys., 37, 401 (1979).
Y. Itikawa, H. Takagi, H. Nakamura, and H. Sato:Phys. Rev. A, 27,1319 (1983).

51
RIKEN Accel. Progr. Rep. 18 (1984)

111-2-5.

Doubly Differential Cross Sections for Electron-Impact
Ionization of Helium
A. C. Roy and T. Watanabe

When energetic electroris collide with atoms or
molecules, one of the important processes that takeplace is ionization. Ionization cross sections areimportant quantities in studies of planetary atmospheres, plasma physics, and radiation physics.
Detailed knowledge of the process of ionization is
also of intrinsic interest because of its fundamental
nature, which has not yet been understood completely, however.
When helium atoms, initially in the groundstate, are ionized by electron impact, the processwith the largest cross section is that in which one
electron is ejected and the He+ ion is left in the
ground statee-+He (ls 21 8) ~ He+ (ls)+2e-(1)

The two electrons in the final state are indistinguishable, but it is convenient to refer to the fasterelectron as the scattered electron and to the slower
one as the ejected electron. If the directions of theejected and scattered electrons are measured incoincidence, together with the energy E2 of theejected electron, a triply differential cross section
can be defined as(2)nique of Roy et al. 2) ,3) that reduces the eightdimensional Glauber amplitude for the He (e, 2e)
He+ process to a two-dimensional integral.
In the GA, the amplitude for the ionization of He
IS given by-+-+
ik f -+ -+ -+-+-+F(g,k2)= 2n: Jdb dr1 dr2 1>r*(rb r2).r (b ;-;1, ;2) 1>i C;1, -;2) eiq·b(4)2i2Ib-71] 2i7J[ Ib-7
where r(b, rl, r2) - I- -bb 1] 7J
-+.-+

-+

_

[

q=k-h1and r;= Ijk. Here k, hI, and k2 are the momenta of
the incoming, scattered, and ejected electrons,
respectively, and q represents the momentum
transfer. b, ;1 and ;2 are the respective projectionsof the position vectors of the incident particle andthe two bound electrons onto the plane perpendicular to the direction of the Glauber path integration. In Eqn. (4), b, ;1, and;2 are all coplaner and
1>i ('I, '2) and 1>r(;b ;2) represent, respectively, thewave functions of the initial and the final states of
the target. For the initial state of He we have chosen
the following form:q,(5)This is a function of the energy of the incident
electron E, the energy of the ejected electron E2 ,and three angles, namely, the polar angle of scattering of the fast electron 01, the polar angle of ejectionof the slow electron 02 and the azimuthal angle
1>2 of the direction of ejection with respect to theplane of scattering.
The doubly differential cross section is given byd (J"d (J = ~"dk2 " "
dk1 dE2
dk1 dk2 dE2
2

where

whereas for the final state of He, we have adopted
the following:

1>r('I, '2)=2-1/ 2 [1.1(;1);(12 (;2)+1.1(;2);(1 (;1)]
2

(7)

where

3

X~2(;)=(211:)-3/2er1r/2 r(l+ir)eik2';IFl( -ir, 1;(3)

We have obtained the doubly differential crosssections (DDC8) for electron-impact ionization of
He in the incident energy range 224.58-2,824.58 eV
for the scattering angle of 45°. We have studied only
the symmetric case, i.e., the two outgoing electrons
have equal energies. The present calculation isbased upon the Glauber approximation (GA).1)
The calculation has been performed using the tech-(6)-i(k2r+k2';))

(8)

with

1.1(;)= ).'3/211:-1 / 2 e-J/ r

(9)

and

r=Z/k2In the present formalism, we have chosen Z = ).
so that ifJi ('1 , ;2) and ifJr('I, ;2) are orthogonal to. each other.
The triply differential cross section is given by

52

A. C. Roy, et al.

Table 1. Doubly differential cross sections d 2ajdk1dE2 inunits of 10- 6 ao 2 Sr-1 eV-1 in the GA for electron-impact
ionization of He for various incident energies E with E1 =E2 and (h=45 °. ~=24.58 eV.
GA
Experiment d )E-~(eV)a)

200
300
400
500
600
800
1,000
1,500
2,000
2,800
a)
b)

e)

d)

Ib)

lIe)

317
145
79.8
49.4
33.1
17.3
10.4
3.99
2.01
0.888

335
152
83.5
51.6
34.5
18.0
10.7
4.13
2.07
0.981

417
195
107
65.8
41.9
21.0
12.5
4.84
2.36
0.989

~ denotes the binding energy defined by E-E1-E2.
Present Glauber cross sections calculated with the
choice 1 wave function for the ground state of He.
Present Glauber cross sections calculated with the choice
2 wave function for the ground state of He.
Ref. 6.

Table 1 presents our GA results for the DDCS
along with the corresponding experimental data6)
for the ionization of He by electron impact in theincident energy range 224.58-2,824.58 eV for E 1=
E2 and 01=45°. We see that the GA cross sections
obtained with the choice 1 wave function are always
smaller than those obtained with the choice 2 wave
function. At an incident energy of 2,824.58 eV thecross section predicted by choice 2 differs fromthose by choice 1 by 5%, while at an incident
energy of 224.58 eV they differ by about 9%. Thismeans that with the decrease in incident energy thedifference of cross sections predicted by two choices
does not alter substantially. In addition, we noticethat in the present case of symmetric geometry the
GA cross sections are in reasonably good agreementwith experiment. As expected, the agreement decreases at lower energies.
References
1)

d 3(J
kl k2
--+ --+
dkl dk2 dE = - k - I F(q, k2) 12
2(10)The present calculation for DDCS has been performed in two different choices of wave functions
for the ground state of He. Choice 1 involves the
adoption of the single-parameter product type wave
function with a screening parameter A= 1. 6875,4)
whereas choice 2 concerns the use of a similar
single-parameter product type wave function witha screening parameter A= 1.618.5 )

2)

3)
4)

5)
6)

See, for example, E. Gerjuoy and B. K. Thomas: Rep.
Prog. Phys., 37, 1345 (1974); A. C. Roy and N. C. Sil:]. Phys. B, 12, 497 (1979) and references therein.
A. C. Roy, A. K. Das, and N. C. Sil: Phys. Rev. A, 23,
1662 (1981).
A. C. Roy, A. K. Das, and N. C. Sil: ibid., 28, 181(1983).
H. A. Bethe and E. E. Salpeter: Quantum Mechanics ofOne- and Two-Electron Atoms, Academic, New York
p. 147 (1957).
See, for example, J. E. Golden and J. H. McGuire: Phys.
Rev. A, 13, 1012 (1976).
B. van Wingerden, J. T. N. Kimman, M. van Tilburg,and F. J. de Heer:]. Phys. B, 14, 2475 (1981).

53
RIKEN Accel. Progr. Rep. 18 (1984)

Potential Energy Curves of Na~, K!, and Na 2

111-2-6.

H. Sato, M. Kimura, * and R. E. Olson**

The investigation of ion-atom collisions forenergies from low to intermediate region (0.1-20
keV/amu) is very active. Recently, several calculations of charge transfer and excitation cross sections
by the molecular treatment have been carried out
and their results agree well with experimental ones.
In this energy range, contribution from valence
electrons to the cross sections is dominant and thatfrom core electrons is negligible. Therefore, themethods which replace the effect of core electrons
by some analytical potential are very useful tocalculate potential energies and wavefunctions ofmolecular system. The molecular calculation codeby the pseudopotential method developed by
Bardsley and colleagues!) was revised to work on
F ACOM 380 at Computer Center of RIKEN.
They adopted a pseudopotential of the Gaussian
form given by

Na2 are calculated by this code. These systems arevery interesting and many experimental and theoretical studies have been published. The pseudopotential parameters and the basis functions employed in
the calculations are given in Tables 1 and 2. The
N a~ molecular ion involves a valence electron.
Eighteen STO's are used for a-state and 8 for 1rstate, 4 for a-state. Results are shown in Figs. 1 to
3. It is well known that the pseudopotential method
can not be applied to the molecular calculation at asmall internuclear distance. As can be seen from
Table 2. Slater type atomic orbitals employedin the calculation.
Na

K

Orbital exponent

Orbital exponentV(;) = L;A[ exp [-Clr2] 11m> <1m I
I, m

3p

where AI and CI are I-dependent parameters, while
ad, a q , and d are the dipole and the quadrupole
polarizabilities, and the cutoff distance, respectively.
Extensive review about the pseudopotential is given
by Bardsley.2) Slater type atomic orbitals (STO's)
are used as basis functions. Molecular wavefunction
is expressed by a linear combination of the Slater
determinants constructed from STO's, not frommolecular orbitals.
The potential energy curves of N a~, K~, and3d4s

Pseudopotential parameters in atomic units.
Na

Ao
Al
A2

Co
C1
C2
ad
aq

d

10.28195
2.692467- 1.452763
1.294506
0.681447
1.0
0.945
5.0
1.1

K

Ao
Al
A2

Co

''21

ad
aq

d

9.568369
2.897295-3.916641
0.709742
0.363969
0.748353
5.47
41.5
1.5

4s

4p
5s

a-state of Nat

0.20
0.15
'3'

0.10

~

kl

0.05

>.
tl.O

~

OJ

0

"iii

~ - 0.05

2oa..

Na (4s) + Na+- 0.10Na(3p) + Na +i

- 0.15

Na (3s)+Na+- 0.20-0.25* JILA, University of Colorado, U.S.A.
** Physics Department, University of Missouri-Rolla,
U.S.A.

1.135
0.700
0.350
1.134
0.689
0.394
0.820
0.556
0.358

0.25 "--'1II""""1r-~----r---r---'---'~

Table 1.

3s
3d

0.790
2.487
0.694
0.372
0.721
0.558
1.484
0.337
0.290

2s
3s

0

5

10

15

20

25

30

Internuclear distance R (!au)

Fig. 1.

Potential energy curves of O'-states for Na~.

H. Sato, et. ai.

54

0.25

0.25
0.20

:;~

~

~

1l'-

0.20

state of Na;

0.15

0.15

--;

0.10

~

~

0.05

>.

~
c

())

0.10

iti

0.05

~

0

0

())

c

())

ro -0.05

Q)

ro

:;:;

c

-E -0.10-0.05

j -0.10Na (3p)+Na +

a..

o

a..

-0.15
- 0.20

-0.15
-0.20

-0.25
0

5

10

15

20

25

- 0.25 ~--I..._-'----IL.....-.--L.._.J......--..Jo 5 10 15 20 25 30
lnternuclear distance R (au)30Internuclear distance R (au)Fig. 2.

8-state of Na;

Potential energy curves of 1l'-states for Na~.

Figs. 1 to 3, the results for a- and o-states arereasonable at all the internuclear distances calculated. On the other hand, the potential energy
curves for n-states behave incorrectly in the range
of internuclear distance less than 3 atomic units.
Fortunately, contribution from the impact parameter less than 3 atomic units to the cross sections issmall. Similar results are obtained for the K~ molecular ion. The N a2 molecule has two valence
electrons. Forty two STO's are used as basis functions and 116 configuration functions are con-Fig. 3.

Potential energy curves of o-states for Nat.

structed for the lL~ state. The obtained potential
energy curves show incorrect behavior similar to
those of n-states for Na~ at a small internuclear
distance. This comes from the fact that the n 2
configurations are taken into account in the calculations.
References
1)
2)

J. N. Bardsley, B. R. Junker, and D. W. Norcross: Chern.
Phys. Lett., 37,502 (1976).
J. N. Bardsley: Case Stud. At. Phys., 4, 299 (1974).

55
RIKEN Accel. Progr. Rep. 18 (1984)

111-2-7.

Electronic Property of Extremely High-Density andHigh-Temperature Materials
K. Fujima and T. Watanabe

In inertial-confinement nuclear fusion expenments fuels are compressed to the region of a few
hundred times as high as that of usual solid density,!>During the compression, the fuels are heated ashigh as thousands of electron volts. Owing to theexperimental progress, theoretical investigations on
the electronic properties of high-density matters
become more than important than ever. The atomic
processes in these medium, such as X-ray emission
or absorption and a charge stripping process ofincident heavy ions, are influenced by these electronic properties. In the study of these problems,
there are two difficulties which should be overcome.
The first one is how to treat randomly moving andclosely existing ions. The second one is the formulation of the electronic states at high temperatures.
Many theoretical approaches to these problems
have so far been reported using various methods
and models. 2) We study the applicability of the
DV-Xa calculation to these problems.
Though ions move randomly in mediums, weapplied the DV-Xa calculation for the Ne clustersof simple cubic and face-centered cubic at fixedatomic positions (see Fig. 1). The density of Ne
is taken to be about one thousand times of the usual
solid density and the electron temperature isassumed to be zero for the first step. The physicalbackground of the present cluster model is basedon the discussion that the configuration of ionsbecomes a spacial closest pack at a high-density
limit.
In the D V- Xa method, single electron states arecalculated on the basis of effective potentials which
involves the exchange interaction between electrons
in an approximate form of the local potential. The
local potential is expressed as being proportional
to the cubic root of the local density p(r) at eachpoint. 3) The total Hamiltonian of the Neg (simple
cubic) or of the Ne13 (face-centered cubic) cluster
is given by

where N is the number of electrons in the cluster
and Vc is a Coulomb potential term and Vex
represents an exchange interaction term in atomic
units. Appropriate boundary conditions for elect~onic wavefunction are taken as that the charge
neutrality can be satisfied within a limited volume
considered.
One of our calculation results is given in the Fig.
2, which shows that one electron energies are given
as a function of internuclear distance for the facecentered cubic Ne13 clusters. For the simple cubic
Neg cluster, the energy diagram is not different
appreciably from that of N e13.
Atomicdensity (atoms/cm 3 )

10 25

10 23

10

3
(x102eV)

o

o

-3

2
:0 -20

o

-6

-30
-9
2

Ca)

( b)

Fig. 1. Model cluster for (a) a simple-cubic Nea cluster and(b) a face-centerd Ne13'5

10Interatomic distance (a.u.)

Fig. 2. Orbital energies for a face-centered Nel3 cluster asa function of internuclear distance R, or atomic density.

56

K. Fujima, et al.

The 2s and 2p orbitals form band-like structure
and broaden their energy levels, which can represent
the so-called continuum lowering. The core 1s
orbital gains energy with decreasing internuclear
distance from 10 to 2 a.u., because the screening
charge of the nuclear attractive potential increases.
At an extremely high density region (higher
than 3 X 1023 atoms/cm3), kinetic energy of electrons rapidly increases because they are confinedin a small limited volume. The increase in kinetic
energy of outer shell electrons is also seen in theregion around 1023 atoms/cm3 ; this corresponds tothe pressure ionization.
We considered the cluster model as each atom isfixed in its minimum position. This model is different from that of high temperature plasma. The

motion of ions can be taken into account by considering the deformed clusters which represent
their vibrational motion. The effect of high electron
temperature can be treated by taking the FermiDirac distribution for electron occupation in theirlevels. Studies are in progress.
References
1)
2)

3)

Ann. Rep. Laser Fusion Program, Institute of Laser
Engineering (1980, 1982).
J. C. Stewart and K. D. Pyatt, Jr.: Astrophys. ]., 144,
1203 (1965); S. Skupsky: Phys. Rev. A, 21,1316 (1979);
U. Gupta and A. K. Rajagopal: ]. Phys. B, 12, L704
(1979).
H. Adachi, M. Tsukada, and C. Satoko: ]. Phys. Soc.
]pn., 45, 875 (1976).

57

RIKEN Accel. Progr. Rep. 18 (1984)

111-2-8.

Electron Stripping Cross Sections from Multiply Charged
Ions by Hydrogen and Helium Atoms*
S. Karashima, H. Kawagoshi, T. Watanabe, X. Cheng,**
Q. Ma,** Z. Liu,** and Y. Liu**

Recently experimental and theoretical results on
the electron loss and capture of ions in matter havebecome important in the charge equilibrium
problems. A few studies have been made in experiments as well as in theoretical calculations l ), 2) for
electron loss processes of atomic hydrogen.
In the present paper, we calculate electron stripping cross sections using the binary encounter
approximation (BEA). The electron loss process ofa multiply charged ion Aq+ (atomic number Zl) bycollision with a hydrogen or a helium atom B isexpressed as(1)

Mter an electron is stripped from the ions, thecharge of the ions becomes (q+ 1) and B does
neutral or ionized states, i .e., B(~) means all electronic states of the atom including ionized states.
Our treatment of the electron loss processes isbased on BEA, in which the nucleus of B screenedby the surrounding electrons collides with electrons
in the ion Aq+. Here we confine ourselves to thecase where the screening effect of the B nucleus byelectrons is negligible, i.e., Z2(atomic number
Z2 of B). For the time being we treat Z2= 1, 2 andq~3 Z2. One of the basic approximations in BEA
is that the ion interacts with only one electron or
nucleus of the target atom at a time.
In the calculation for Li 2 ++H, we have foundthat BEA will give approximately reliable resultsof the Process (1).2),3) The characteristic feature ofthis process lies in the large magnitude of momentum transferred to the electrons in the ion Aq+ on
occasions of close collisions with the neutral atom B.
Such a collision with large momentum transfer canwell be approximated by the classical description.
This feature also supports that BEA is considered
to be one of the proper methods.
Evaluation of the cross section requires information about the momentum distribution of electrons

in the ion. In order to obtain charge stripping crosssections of the ions over the wide range of projectile
species, we employ the Thomas-Fermi (TF)
statistical method for the calculation of momentum
distribution in the ion. In the present paper the
momentum distribution f(p)dp and the probability
Ir(p)dp of an electron having momentum between
p and p+dp at r in the potential VCr) are written by
the TF model 4) asfr(p)f(p)dp= 30 Ir(p)dp nCr) 4/'rr2 dr=4/'r ~:(P)Ir(P)dP n(r)r 2 ( ; ; )dE

(2)

<q

* Colaborated work of Atomic Processes Laboratory withtheoretical physics group at Chinese University of
Science and Technology.
** Department of Modern Physics, Chinese University of
Science and Technology.

N

E

u
'-'"

0; EXP[RIMENTAL

VALUE

Fig. 1. Electron stripping cross sections for cq+ (q= 3-5)
ion by collision with a neutral H atom as functions of impact
energy. Dotted lines show the calculated BEA cross sectionsin the case of t arget bare nuclear model, i.e., the screening
effect of 1 s electrons in the hydrogen target is ignored, evenwhen q is not larger than 3 Z2. The experimental cross section
for Cq+ + H2 7 ) is compared directly with our data not multiplied by 2. This is because in the ejection of a tightly boundelectrons in the ion the close collision with one of protons
in H2 is required. In this case the other proton lies in a
distant position and it is considered to exert a negligible
effect on the ejection process of electrons by the first proton.

S. Karashima, et aZ.

58

10- 16(t = 4(t= 6{£ = 8C[, = 10(t = 14(t= 16(t = 1710-)24

Fig. 2. Electron stripping cross section for N eq+ (q = 3- 9) ion
by collision with neutral H atom as functions of impact energies.

E (eV/ amu)
Fig. 3. Electron stripping cross section for Arq+-ion bycollision with neutral H atom. - - - - preliminary results.

and41t'p2 dp
Ir(p)dp= 41C Pmax 3/3
3p2= -"- 3 dp

Prnax
=0

for p ~Pmax} (3)for p> Pmax

where r is considered to be a function of E as r(E)with relation (p2/2m)+ V(r)=E and n(r)=(81C/3h3)
Pmax3 (r) is the number of electrons per unit
volume at a distance r from a nucleus. The valueof the maximum momentum Pmax is given by theTF equation:v2V(r) = -41C nCr) e2(4)n(r)= (81C/3h 3) (2m(V(r)-E o)3/2,(5)
Pmax 2= V(r)-E owith V(r)= Zle 2/r for r ~ 0, where Eo is obtained

is a velocity distribution function in Eqn. (2).
Under this background we have made calculations of Process (1) using BEA for Cq+, Ne q +, andArq+ projectile ions (q= 3""Z) and a H target atom.
Figures 1, 2, and 3 show the preliminary resultsfor electron stripping cross sections. In the caseof a He target, the cross section can be expressed by that of H target multiplied by a factorof 4 (= Z22).
References
1)
2)
3)

such that 41t'~n(r)r2dr=N (N is the number ofelectrons in the ion).
When we define the ionization cross section,(Jni(v, w), in the laboratory frame for the collision
between a nucleus with a velocity v and the atomic
electron with a velocity w,5),6) the cross section forelectron stripping from Aq+ by collision with thetarget nucleus (In(v) is given by(In(v) = ~~ (Jni(v, w) few) dw(6)

where few), which is determined by the TF model,

4)
5)

6)
7)

M. B. Shah and H. B. Gilbody: J. Phys. B, 11, 121(1978).
T. Shirai, K. Iguchi, and T. Watanabe: j. Phys. Soc.
jpn., 42, 238 (1977).
T. Watanabe: Proc. 1984 INS Int. Syrnp. Heavy Ion
Accelerators and Their Application to Inertial Fusion,(eds. Y. Hirao, T. Katayama, and N. Tokuda), Inst.
Nuclear Study, Univ. of Tokyo, Tokyo (1984); T.
Watanabe: J. Phys. B, 18, L111 (1985).
C. A. Coulson and N. H. March: Proc. Phys. Soc.,
London, Sect. A, 63, 367 (1949).
L. Vriens: Case Studies in Atomic Collision Physics I,(eds. E. W. McDaniel and M. R. C. McDowell), NorthHolland, Amsterdam, Chap. 6, p. 335 (1969).
L. Vriens: Proc. Phys. Soc. London, Sect. A, 90, 935(1967).
H. Tawara, T. Kato, and Y. Nakai: Electron Captureand Loss Cross Sections for Collisions between Heavy
Ions and Hydrogen Molecules, lnst. Plasma Phys.,
Nagoya Univ. , Nagoya, IPPJ-AM-28 (1983).

59
RIKEN Accel. Progr. Rep. 18 (1984)

111-2-9.

Coupling In Ar-Ti, Ar-Co, and Ar-Zn Systems
K. Fujima, T. Watanabe, and Y. Awaya

The target atomic number (Z2) dependence of
simultaneous K -shell and L-shell ionization of
Ar ions has been studied by the experimental groupof RIKEN.1),2) It has been observed that the intensity ratio of Ka hypersatellites to Ka satellites
shows oscillatory dependence on Z2 and it has beensuggested that this oscillatory behavior reflects thecontribution of 2Pa-2Plr and 3da- 3dlr rotational
coupling electron promotion process to the ionization of K electron of Ar ions in addition to thedirect ionization process. The incident energy of
Ar ions in lab system was 0.83 MeVjamu, that is
EjAUk=0.14, where E is the total energy of Ar ions,
A is the mass of Ar ions in electron mass unit andUk is the binding energy of K electron of Ar ions(in this estimation, the value for neutral atom isadopted). The purpose of the present work is toestimate this contribution.
The basic idea and the calculation technique havebeen made by Briggs and Macek3) and Watanabe
et al. 4 ) The details of presented calculation arealmost the same as those of Watanabe et al. 3 ) Furthermore, the appropriate extensions have been madein order to treat a hetero-nuclear problem .
. The time-dependent wavefunction for Ar(ls)orbitals W(r, t) at the target and projectile distanceR(t) with an initial relative velocity of v and impact
parameter of b satisfies the time-dependent Schroedinger equation
ifz aa~ =H(r, R(t))W

(1)

W(r, t) is written as the superposition of 2Pa and2plr molecular orbitals with time-dependent coefficients a1 and a2 as,

The matrix element V 12 is calculated as,
V 12= ~ P2pa ~ Lr. P2Plr d 3x· exp [ - i ~ (S2pa- s2plr)dtjfz](5)where L r. means rotational operator and S2plr or
S2pa stand for one-electron energy and v is therelative velocity of collision system.
The 2Pa and 2plr molecular orbitals can be
written by the anti-bonding and bonding LCAOMO (molecular orbitals constructed by linear
combination of atomic orbitals) of the Is and 2p
orbitals of Ar and those of target atom, i.e., Ti,
Co and Zn, with the coefficients C's as,
P2pa= C 11 PlsAr - C 12 PI?
P2plr=C21 P2pAr+C22 P2pT

(6)

The atomic orbitals PIs and P2p in Eqn. (6) aretaken to be the Slater type orbitals with the adjusted
orbital exponents (Is and (2p,
PIs=J (~s3 e-r.lS r
P2p=

(7)

J (~ re-r.2pr
5

The orbital exponent (R) for each atomic orbitalis interpolated by the values for isolated and ,united
atom limit using the formula,(2( (X) )-(2(R)(2( (X) )-(2(0)

s( ( X » - s(R)

s(

(X»-

s(O) .

(8)

The coefficients C's in Eqn. (6) are equal in thehomo-nuclear case. In our case C's are derived byminimizing 'Or maximizing the orbital energy<E> of Eqn. (6) with respect to the diatomic
Hamiltonian H d ,(2)

Substituting Eqn. (2) into Eqn. (1) and omitting theradial coupling term, the coefficient a1 and a2 in
vector form follow the coupled-equation with' therotational coupling matrix V,
ifz!

,A= V(t)A

(3)

where

(4)

Table 1. K-shell ionization probabilities for Ti-Ar, Co-Ar,
and Zn-Ar systems.
2pu-2plrtransitionp~obability

Ti+Ar+10

A 2
K-shell ionizar ption probability
component
:
b
cr
. 2
Y BEA (ellectnt fative charge ofsae
projectile)0.0194 a.u.
0.536 X 10-18 cm 2

0.54

Co+Ar+ 10 0.0012 a.u.
0.034 X 10-18 cm: 2

0.60

Z + A +10 0.0010 a.u.
nr
' 0.028 X 10-18 cm2

0.32 ,

1.5 X 10-18 cm 2(+14 for Ti), 1.7 X 10-18 cm 2(+15 for Co)
2.8 X 10-18 cm 2(+20 for Zn)

60

K. Fujima, et al.

a

Ti 2p
Ar 2p

Ar2p

>-

~

Arls

<II

C
l.LI

Ti ls
-200
-350
0,0

0,5

1,0
R

1,5

o

(a, u,)

0,5(a)

The correlation diagrams for (a) Ti-Ar and (b) Co-Ar systems.

0.4
Ti - Ar

(a)

0.2

:0-

0:.-

:0
III
.a

1,5

(b)

Fig. 1.

>-

1,0

R (a, u,)of V in Eqn. (4) can be calculated analitically.
R(t) in Eqn. (1) is treated classically and calculated
assuming the screened Coulomb scattering potential.
The coefficient A is integrated numerically with
the initial condition, C1j = 1 and C2j =0 (j = 1, 2)
for t=-co.
The transition probability PCb) at the impact
parameter b is obtained as,0P(b)= 1a2( + co) 12

0.4
Co- Ar

...a.
0

(b)
0.2

and the total cross section for K-hole production is
given by the integration of PCb) respect to b,n=2tr ~~ P(b). b· db

o OL---->O'--...>L-...........~--~L-.....:==-----l0.05
0.1
I mpact parameter b (a,u.)Fig. 2, Dependence of transition probabilities PCb) on impact parameter b at an incident energy of 33 MeV for Ar ion.
(a), Ti-Ar; (b), Co-Ar systems.

(9)

under the constraint(10)

where Hd is the summation of the kinetic energy ofthe electron and the Coulomb attractive potentials
from the target Zl and projectile atoms Z2,

Hd=-~V2+ Zl + Z2
2m

r1

r2

(11 )

The left hand side of Eqn. (9) and the matrix element

(12)

(13)

The obtained results are tabulated in Table 1
together with the direct ionization probabilities by
calculated binary encounter approximation (BEA).
The obtained K-hole production probabilities
by the rotational excitation are large for Ar-Ti and
Ti-Co systems and negligibly small for Ar-Zn
system. These results can explain the experimental
feature qualitatively. However, the calculated crosssections are rather small compared with those by
BEA. This may be owing to the over-estimation of
BEA probabilities which assume the effective charge
for projectiles atoms in somewhat arbitrary way
and to neglecting a "the binding effect." The effective charge which is felt by K-electron of Ar ions isestimated by the assumption that the electrons withlower velocities than that of Ar ions can be removed.
Moreover, in the case of the Ar-Co and Ar-Zn
systems, the 2ptr orbitals do not correlate directly toK. Fujima, et al.

the atomic 2p orbital for the Ar atom (Fig. 1).
Though the transition probabilities between 2plr
and 3dlr states by the radial coupling mechanism
should be calculated, we took the component of the
2p of the Ar in 2plr molecular orbital at R(O) to be ameasure for this transition. These values are alsotabulated in Table 1.
The difference in the total ionization cross section
originate from the difference of energy diagram for
Ti, Co, and Zn systems because the coupling
matrix elements for V are almost the same in these61

systems. These features can be visualized in Fig. 2.
References
Y. Awaya, T. Kambara, M. Kase, H. Kumagai, J. Urakawa, H. Shibata, T. Masuo, J. Takahashi, and M.
Namiki: RIKEN Accel. Progr. Rep., 17, 49 (1983).
2) Y. Awaya, T. Kambara, M. Kase, H. Shibata, H. Kumagai, K. Fujima, J. Urakawa, T. Masuo, and J. Takahashi:
Nucl. Instrum. Methods, to be published.
3) J. S. Briggs and J. Macek: J. Phys. B, 5, 579 (1972).
4) T. Watanabe, M. Koike, and F. Minami: l. Phys. Soc.
lpn., 34, 781 (1973).
1)

62
RIKEN Accel. Progr. Rep. 18 (1984)

111-2-10.

Theory of Radiative Electron Capture I: Nonrelativistic
Treatment and Theoretical Paradox
K. Hino, I. Shimamura, N. Toshima, and T. Watanabe

The photon emitting process followed by transfer
of an electron from a target to a projectile ion witha high incident velocity

given in terms of the center-of-mass coordinates rand (] in Fig. 1

Aq++(Bql++e) -* (Aq++e)+Bql++hv
is called "radiative electron capture (REC)," which
is a competitive process with usual non-radiative
charge transfer (electron capture (CT)). In highvelocity ionic collisions and also in highly-charged
projectile collisions, a role of the REC process
becomes essential. 1)
Shakeshaft and Spruch 2 ) investigated a two-bodyproblem in the presence of a radiation field anddiscussed the so-called "spurious radiation," which
was introduced as photon emission based on the
motion of a center-of-mass, and they showed theconditions that this spurious radiation term might
be deleted. The extension of such conditions to athree-body problem can be easily made. As a result,generally, the only way left to avoid the spurious
radiation is to make use of the center-of-mass frame
for the three-particle system.
In the formulation of the REC process in the present approach, we take into account nucleus contribution as well as electron contribution to the photon
emission. Finally, we have reached a conclusionthat the nuclear contribution to the photon emission
becomes of the comparable order to the electron
contribution. This seems to conflict with our common sense that the intensity of photons originatedby the motion of a particle with a mass M andcharge q in atomic units is smaller than that of anelectron by a factor of q/M.
In our calculation, we assume that one photon isemitted, and that the Coulomb distortion of the wave
function of scattered particles is not important, andcan be ignored. Furthermore, we use atomic units
throughout this report. In accordance with the above
assumptions, the transition matrix element for the
REC process, Tfj, can be written by the first order
perturbation (Born) approximation between theinitial and final states (X j and Xf) with the interaction H', as(1)
The asymptotic initial and final states, and, areand
Xf=(2n )-3~d3qgf(q)ej( ~Kf+bq )·'ei(aKr - q)·u \1 >(3)where \ 0> and I 1> are the vacuum photon state
and the one-photon state, gi and g f the initial andfinal wave functions of bound states in momentum
space, respectively, and Ki and K f the incident andrecoil momenta, respectively. Writing the massesof the projectile ion, the target nucleus, and thebound electron as mI, m2, and 1, respect)vely, we
will use the notations a, b, and p. as a= ml/(ml+l),b=m2/(m2+ 1), and p.=ml(m2+1)/(ml+m2+1). H'
is taken as the interaction between particles andthe radiation field, which is given by

H'=-~t~A(i)·Pi
2 j=1 mjC

(4)

where Zi and Pi are the charge and the momentum
operator of the i-th particle, respectively, C thevelocity of light, and A the vector potential. By theuse of dipole interaction in Eqn. (4), the transition
matrix element, Tfj, is expressed by

T fi =- / n [e.{p.(~ - ~+I-b)v
V 2m
m2
m2
- (1

+ ~: )pi} ] gj(Pi)gf*(qf),(5)

where e is the polarization vector of photon, and3, Electron..-,::::'----- ----,f------ -= - . l .

2, Target nucleus

Three - body center-of - mass

Fig. 1. The independent coordinate set in the center-ofmass system

63

K. Hino, et al.

(J) the energy of an emitted photon, Pi and qf theinitial and final momenta of a bound electron given
by Pi=Kf-bl( and qf=a(Pi-v), respectively,
where v=K;j p.. By using the peaking approximation, that is, gi(Pi) is negligible except for Pi~O,
the photon distribution cross section is giv~n byd2a( dmdQ)= a3c v2m (e.v)2[ (Zl _ bZ

2

1r

3

f1

ml

m2

+1-b)]2IgA-av) 12X~d3pj gi(pJ 20 ((J)- ~ av2
1

1+apj,v+€/-€i)(6)

Where Q is the solid angle of the emitted photon,f f and f j are the initial and final energies of thebound electron, respectively. The term in thesquare brackets indicates that the intensity of photon
emitted from nuclei is of comparable order inmagnitude to that from an electron, and hence theradiation intensity of the REC depends on themasses of a target and a projectile ion, respectively,
which is here called "isotope effect." For instance,
REC intensities p(4He/ 3 He) i.e., isotope effect between collision systems, N eq++ 3He and N e q++
4He, is easily estimated as nearly equal to be two.
However such an isotope effect was not observed
within seven percent error in measurements by
the experimental group of RIKEN with 11 0 MeV
N e10+ and N eq+ bomberdment. 3) This curious andnon-selfcontradictory effect cannot be theoreticallyexplained without a three-body fully covariant
treatment, which will be indicated in a succeeding
report.
References
1)
2)
3)

J. S. Briggs and K. Dettmann: Phys. Rev. Lett., 33, 1123
(1974).
R. Shakeshaft and L. Spruch: ibid., 38, 175 (1977).
T. Kambara, Y. Awaya, M. Kase, H. Kumagai, H.
Shibata, and T. Tonuma: p. 77 in this report.

64

RIKEN Accel. Progr. Rep. 18 (1984)

111-2-11.

Theory of Radiative Electron Capture II: Covariant Treatment
K. Hino, I. Shimamura, and T. Watanabe

In the preceding report about the nonrelativistic
radiative electron capture (REC) process, we described the "isotope effect" based on the photon
emission from the nuclei of the three-body system,
which was, however, not observed. The present
report will show the theoretical explanation of thisparadox from the point of fully covariant treatment.
Firstly, the definitions of relativistic notations are
introduced. A scaler product of four dimensional
vectors, A=(A, Ao) and B = (B, Bo), is represented
as AB= AB- AoBo. Dirac's gamma matrices aredefined as r = -ifia, and r4=fi, all of which are
hermite and satisfy the anti-commutation relation:{rp, rv}=2o pv , (fl., v = 1~4). In addition, freepropagation functions of half-spin fermion andphoton are given as:

SF(X-X')= <0 1T[¢(x), ¢(x')] 10>i ~eip(x-x')- - - - d4(27r)4
1> ipr+ m - iE

(1)action Lagrangian density is redefined asLint

By the use of Eqn. (6), S-matrix, < 0 I V (00,- 00) I<01 V (00, -00)10>= <0 1Texp(i~d4x Lint(x») 10>(7)

and Schwinger's functional derivative l ) about Jp is
defined as°oJp(x)V [Jp]= lim V[JAY) + fo(4)(y-x)]- V[JAy)](8)
The use of Eqn. (8) can lead us to the following
convenient relation:otoJp(x) T[V, a, fi, ... ]= T [V, Aix ), a, fi, ...]

(2)

respectively, where ¢ and Ap are the free field
operators of a half-spin fermion and photon, respectively, ¢ is defined as ¢+r4, and T is Wick's
chronological operator. These two propagation
functions should fulfill the following relations:(rOx+m)SF(X-X') = - io(4) (x-x')(6)0> , is given as

andD F, pv(x-x')= <0 IT [Ap(x), Av(x')] 10>
0plJ-=-=-----:-_
eik(x-x')- _i_ ~ d 4k ----'-'- (27r)4
k 2 -iE. (Feynman gauge)= jp Ap-J PAp(9)where a and fi stand for field operators. Anotherpowerful relation for our purpose is the reduction
formula in the interaction representation, givenby(rox+ m) T[¢(x), ...J=-i o/tX) T [...]

(10)

and

(3)

and

(11)
(4)

We use the natural units (li= c=l) throughout
this report, and ~e consider that fermions always
have a half-spin unless otherwise stated.
Some preliminaries for the covariant treatment
are introduced below. The interaction Lagrangiandensity of fermions and photons, Lint, is defined as(5)
where jp is the electromagnetic current of a fermion,given by iZ¢r P¢' and Z is the charge of the fermion.
Here the external c-number source Jp is introducedin Eqn. (5) as a parameter. Therefore, the inter-

By the way, it is generally known, the fundamental
equation for the nonrelativistic three-body potential
scattering is Faddeev's equation, which is expressed
after some reformations (Weinberg's equation),
7[J'A(+) = ~A+[Gca Vca Go (Vab + Vbc)

+ (cyclic combination for a,b, and c)]?FA(+)(12)
where subscripts a, b, and c are the labels of threeparticles, that is, projectile ion, target nuclei, andelectron, respectively, all of which are denoted in
the previous report 2) as 1, 2, and 3. A subscript, A,
represents the channel, a+(b+c), ~A and ?FA (+)

K. Hino, et al.

indicate the initial asymptotic wave function andscattering one in channel A, respectively. Vij isthe Coulomb potential between particles, i and j.
Go and Gij stand for the three-body Green functions of free particles and traveling particles withfeeling potential V;j) respectively. Now we establish the grand assumption from the viewpoint of
Eqn. (12) that the three-body covariant propagator,
K abe , may follow the Weinberg-like relativistic
equation denoted by:Kabe (123: 456)=SFa' (1: 4) G be (23: 56)\ 12'+ .lj~lf4Xj[Gea (13: 1'3') S'Fb (2: 2') Iabe
· (1'2'3': 4'5'6') X S'F.abe (4'5'6': 7'8'9')· {Iab~ (7'8'9': 10'11'12')+I~be (7'8'9':

Kabe,fJ (0; 123: 456)=(1-Fabe ,fJ (123»-1. Fabe,fJ (0; 123) Kabe (123: 456)
+ (propagators which have no contributions
to S-matrix of REC)
(21)
where
F abc.fJ (0; 123)=<01 VIO>-l.i oJ~(O)· [<0 I VI 0> Fabe (123)]

S'Fa (x: x')= < 01 T[V ¢a(x)'¢a(x')] 10>/ < 01 VIO>

(14)

S'F,abe (xyz: x'y'Z')=SFa (x: x')· S' Fb (y: y') S' Fe (Z: Z')(15)

Gae(XZ: X'z')=<OI T[V¢a(x) ¢c(Z)'¢a(X') ¢e(Z')] 10 > /<01 VIO>

(16)

(22)

S-matrix of REC can be easily obtained from Eqn.
(21) by the following procedure: to, t1, t2, t3 -++ 00 and t4, t5, t6 -+ - 00. The final form of REC
S-matrix in the lowest-order in momentum spaceis reduced to
S/i=(2w)- 1/2 V-5/2 (2rr)8
X ub(K') cPae(qj, P') MUa (K)'¢>be(qi, P) 0(4) (K+P-K'-P'-k)· 10' 11' 12') }+ (cyclic combination for a,b, and c)] K abe (10'11'12': 456)
(13)
where S' Fa indicates the one-body propagator offermion, a, and Gae represents the two-body propagator of fermions, a and c, which follows two-bodyBethe-Salpeter (B-S) equation. 3) And the all propagation functions in Eqn. (13) are defined explicitly
as:

65

(23)
where V is the normalization volume, U a and Ub
are the free Dirac spinors, ¢>be and cPae are the
B-S amplitudes and M represents the lowest-orderinteraction of REC process, given by
M=Za(rae) ( - iK'rb+mb){ -i(P-K')· re+me}+( -iKra+ma) Zb(r be )· {-i(P' -K) re+me} + (-iK ra+ma)· (-iK'rb+mb) (ree)(24)

Here Zn and mn are the charge and mass of the nth particle, and e polarization vector of emitted photon. Vectors, qi, qf, K, K', P, P', and k, are ex-

Kabc (xyZ : x 'y'Z')= < 0 1T[V¢a(x) ¢b(y)•<Pc (z) ¢a (x') ¢b (y') ¢e (Z')] 10> /· <01 VIO>
(17)

Final state

Initial statec,Electron~... (xyZ.""Z) =1.'D (X-X ')I abcxy.Ibe (yZ: y' Z')

-

(18)

~
and so on, where Da(xx')= (r a ax + ma)0(4)(xX')+iL* (x, x'), L* is the self-energy of fermion, a,
and Ibc represents the interaction kernel included in
the fermion type B-S (Bethe-Salpeter) equation.
Equation (13) can be symbolically rewritten as

Kabe (123: 456) = (1-Fabe (123»-1.S'Fa(1:4) G be (23: 56)(19)a, Projectile ion.b, Target nucleu.s

Fig. 1. The explanation of the initial and the final energymomentum vectors. qi: relative vector of the composite
particle (b-c), q!: relative vector of the composite particle(a-c), K: incident vector of the particle a, K ' : recoil vectorof the particle b, P: barycentric vector of the composite
particle (b-c), P ' : barycentric vector of the composite particle(a-c), k: emitted photon vector.

Now the three-body REC propagator K abe. fJ is
defined by the use of Schwinger's functional derivative method, Eqn. (9), as

p'

K'

P'

p'

K'

K

k.

K abe. fJ (0; 123: 456)= <0 I VI 0> -1. i oJ:(O). [< 0 I VI 0> Kabc (123: 456)](20)KThe grand assumption, Eqn. (13), can give us the
explicit formal solution of K abe.fJ by using Eqn.
(20) as:

p

K

p

K

P

Ib

Fig. 2. Feynman diagrams of the lowest-order REC S-matrix
Dk(P)= -ipfk+ mk (k=a, b, and c).

66

K. Hino, et al.

plained in Fig. 1, and the Feynman diagrams aredescribed in Fig. 2. Under the mass-on shell conditions, ub(K')(iK'rb+ mb)= O and (iKra+ma)ua(K)= 0, we take the nonrelativistic limit in Eqn. (24)by the use of the approximations, < r> ",,-ipj
m and <r4>",,1, where < r> = < u+ru> , toreach the following conclusion in the center-ofmass frame, that is, P+K=P'+ K' + k = O;me Z
ma me Z b
< M >"" 4t· [ -mbma- - amb+me-

ma mb
mb+ mez] (e. V)
e

f.l

(25)

where the reduced mass f.l follows the preceding
report, and V is the relative velocity in the lab.
frame.
On the other hand, another interaction M'
instead of M is defined for the practical purpose as

M'=Za(rae)+Zb(rbe)+Ze(ree)(27)

This is exactly the same answer with that in thepreceding report. Therefore, the interaction, Eqn.
(26), cannot avoid to cause the "isotope effect," butwe can never arrived at this result from the fully
covariant treatment. In such a sense, the "isotope
effect" would be interpreted as the incorrect property of non-covariant propagator. The estimationsof Eqn. (24) in other frames are straightforward but
this will be given somewhere else. The "relativistic
cross section of REC process is now formulatingfrom Eqn. (24).
References
1)

(26)

which, as a matter of fact, leads to the following
result in the center-of-mass frame:

2)
3)

J. Schwinger: Proc. Natl. Acad. Sci. U.S.A., 37, 452,
455 (1951).
K. Hino, I. Shimamura, N. Toshima, and T. Watanabe:
p. 62 in this report.
E. E. Salpeter and H. Bethe: Phys. Rev., 84,1232 (1951).

67
RIKEN Accel. Progr; Rep. 18 (1984)

111-2-12.

Calculation of the L23-M,M1 Auger Energy and the Relative
Auger Rates for Ar 6 +M. Sekiya, T. Noro,* F. Sasaki,* T. Watanabe, and K. Ohno* ;Recently there has been considerable interest in
the Auger electrons produced by heavy ion atom
collisions. Much information can be obtained forenergy level of highly ionized atom and ionization
mechanism from line positions and Auger rates.
Matsuo et al. l ) have measured the argon L-shell
Auger spectrum by 4.3 MeV Ar 3+ impact on Ar.
They have obtained a spectrum characterized by
two sharp peaks located at about 101 eV (A-peak)and 111 eV (B peak). Based on the SCF (selfconsistent field) calculation of Larkins,3) they
identified these two sharp peaks A and B with the
L23-MIMI Auger transitions. They further carriedout high-resolution experiments 2 ) for the A and B
peaks. These peaks split into two peaks (AI' A2 andBI , B2), and the BI and B2 peaks have complex
structure. Their assignments of the A and B peaks
are probably correct, but detailed assignments of the
Bl and B2 peaks and the Auger rates have not been
attempted. We try to classify the nature of the Bl
and B2 peaks by using the configuration interaction(CI) method and calculate relative Auger rates.
In this work, we consider the Auger process of
Ar 6 + (ls 2, 2s 2, 2p 5, 3s 2 , 3p; IS, IP, ID, 3S,
3P,3D)~ Ar7+ (ls 2 , 2s 2 , 2p 6, 3p; 2P)+ecorresponding to the B peak, and estimate approximate relative Auger rates for the B lines.
The calculation is performed as follows. All CI
calculations are single and double excitation CI (the1 s orbital is frozen) from a single reference state.
The atomic orbitals are obtained by the naturalorbital (NO) iteration and two sets of the Slater exponents of the basis functions are optimized for the
Ar 7+ final state and the Ar6 + 3p initial hole state.
In the CI calculation of the initial hole states, theconfiguration state functions (CSF's) for open
channels (e.g. Ar7++e-) are not included. The
calculated Auger energies are corrected for the
spin-orbit effect, whose parameter is obtained fromthe experimental data of Ar7+ L23-MIMI Auger
energies. 2)
For the Auger rates, we assume that the continuum wave function of the ejected electron IS* Faculty of Science, Hokkaido University.

the Coulomb wave function which is normalized tocos (kr,+o+(qjk) 1n 2 kr-7l:(l+1)j2)
as r tends to 00, where k is the wave number, q is
the net charge for the final state, I is the angularmomentum for the ejected electron, and 0 is thephase shift. The Auger rates is expressed as 4)
Wfi=(4jk) I </1 V Ii> 12

where

V= 1:;1/ rij
i=jand I / > and Ii> are the final wave function(including the ejected electron) and the initial wave
function, respectively. In this calculation of theAuger rates, If> and Ii> are assumed to be a single
configuration, because the initial and the final
states wave functions calculated can be expressedalmost as a single configuration. Relative Augerrates are calculated, by assuming that the creation
probabilities of producing the Ar6+ hole states by
the collision are the same for all the initial hole
states. The numerical integration of the radial wave
functions is performed. Results of the Auger
energy and the relative Auger rates are shown in
Table 1 and Fig. 1, respectively. In Fig. 1, the line
positions are adjusted by reducing about 3.0 eV tomake the weighted mean values of the present
calculation to agree with experiment. 2)
Ar 6 + L23-MIMI Auger energy in Table 1
shows that the CI results give a better fit to experiment than SCF results (Larkins),3) but the discrepancy is still large. We consider that the discrepancy is due to the coupling between the continuum and the initial hole states, and the higher
order correlation effect. Figure 1 shows that the]value (the total angular momentum) of the initialhole states for the BI peak are mostly 2 or 3, andfor the B2 peak, mostly 1. It also shows that theBI peak splits into two or three peaks and the B2
peak, into two. The structure of the Bl peak is ingood agreement with the experiment but the agreement is poor for the B2 peak.
Much more information on collision mechanism
may be obtained from the calculation of more accurate Auger rates. The calculation of the absolute
Auger rates is in progress by using CI wave func-

68

M. Sekiya, et al.

Table 1. Ar 6 + L23-MIMl Auger energy including the spinorbit interaction and Auger rates.
} value}=1

Auger energy (e V)mean*(x10 3 )Calc.
"""'-' J = 3.,.,.".,."., J = 2- J= lE3J = O

~ 25

9.7

111.2

30

Relative rates
III

}=3
}=2
}=1
}=2

112.9}
113.5

}=O
}=1
}=1
}= 2

115.6}
115.6

113.8
114.2

116.0
116.1

2ro

IS.s}

113.5

115.9

12.1
7.6
20.t

~

59.3

1.7} 28.5
22.1
2.1
2.6

20

Cl)

>

~
c

'. p

ro

1.2 ~
u

~ 15
"0

2ro
:; 10
u

co

u

5
121.5
}=O
(weighted mean)
Larkins 3)
Experiment 2) Bl 110.3}
B2 113.2

1.0

2.5
114.2
115.1

108

111.3

* weighted m ean energy

tions in which coupling to the continuum states istaken into account, and the continuum wave function with an exchange effect for the ejected electron
is used.
All the calculations are performed on a HITAC
M-280H at the Hokkaido University Computing
Center and a FACOM M-380 at the Institute ofPhysical and Chemical Research (RIKEN).
The results presented here are also reported incontribution from the Research Group on Atoms
and Molecular No. 17, Ochanomizu University,
Tokyo, Japan (1984).

1.4

112
110
Auger energy leV )Fig. 1. Calculated relative rates of Ar 6 + L23-MIMl Auger
for the B lines and electron spectrum obtained by 45. 7 MeV
Ar4+ impact. 2)

References
T. Matsuo, J. Urakawa, A. Yagishita, Y. Awaya, T.
Kambara, M. Kase, and H. Kumagai: }. Phys. B, 16,
L239 (1983).
2) A. Yagishita, T. Kambara, M. Kase, T. Tonuma, T.
Matsuo, J. Urakawa, J. Takahashi, H. Kumagai, and Y.
Awaya: RIKEN Accel. Progr. Rep., 16, 75, 77, 79(1982); T. Matsuo, H. Shibata, J. Urakawa, A. Yagishita,
Y. Awaya, T. Kambara, M. Kase, H. Kumagai, and
J. Takahashi: ibid., 17, 65 (1983).
3) F. P. Larkins:}. Phys. B, 4, 1 (1971).
4) H. P. Kelly: Phys. Rev. A, 11, 556 (1975); H. P. Kelly
and H. S. Kohler: Phys. Rev. A, 3, 1550 (1971).

1)

69

RIKEN Accel. Progr. Rep. 18 (1984)

111-2-13.

Tilted Foil Method Using Thin Carbon Foil

S. Kohmoto, K. Ando, M. Ishihara, and T. Nomura

The tilted foil method (TFM) is very useful for
generating an atomic polarized and thereby, throughthe hyperfine interaction, nuclear polarized beam.
With increasing beam energy, however, the degreeof atomic polarization generated decreases. 1) ,2) Also
since at a high energy region, more electrons are
stripped from ions than at low energy region, thedegree of nuclear polarization should decrease.
It is the purpose of our experiments to generatecharge-non-equilibrium ions by using thin carbon
foils so as to see if it is possible to generate polarized
ion beams at the high energy region.
Ion beam (14N2+ and 14N3+) from RILAC was
focused on 4 mm X 6 mm carbon foil. First of all, it
was necessary .to search an energy region wherecharge-non-equilibrium is achieved by using a thinfoil. A monochromator was used for scanningwavelength. For this experimental stage, foils were
not tilted so as to minimize the foil thickness. No
optical elements such as a )./4 plate and a linear
polarizer were inserted in the optical path to gain
the photon numbers.
Figure 1 shows light spectra at three incident
energies: EN =6.25, 11.38, and 28.81 MeV. The
spectra of Fig. 1 (a), (c) and, (e) were measured byusing thick carbon foil, whereas thin carbon foil
of 0.7 or 0.8 pgjcm 2 in thickness was used for thoseof Fig. 1 (b), (d), and (f). Spectral resolution is, inall cases, about 2 nm. Peak assignment is done
according to the wavelengths in literature.
At incident energies EN=6.25 and 11.38 MeV,
the spectra from the foils of different thicknesses

Thick foilThin foil

0.2(b)1\ 6.25 MeV

1\

1\11

II:. '
Ii ... .,!

()c-......

2c 0.1
::J

0
()

II

.'il~!
r

l :
0.0

...;

:~.

~

.l.·...·:l ...

: . . . ;",- .•~w 'AWJ • ~,:",,:~.;..,'~

350.:.. •.;/j400
0.06 11.38 MeV

f\

0.04

.1\

0.02

0.00

'.

~·'Y. t.,.~~:.

(d)

:
~

.>
/1
- ...~,-..;.J.~. ',,""''''::,J~

I

c

::J
0
()

0.2

~

()

.........

2c(e)28.81 MeV

0.2

(f)

28.81 MeV

0.1

..
0.0

~

.

..., ..,.:.,.
350,) L··..~.·,:....,....·:·..·400I450
A (nm)

500

400

450
A (nm)

Fig. 1. Light spectra from 14N ions after passing through carbon foil. Photon counts arenormalized by integrated current. Normalization of (c) and (d) is different from those ofothers because of the different foil positions. Spectrum (e) is only partially measured.
Beam energies, ion charges and, foil thicknesses are as follows: EN = 6.25 MeV 2+ ion[(a) 32 pgfcm 2 ; (b) 0.8 pgfcm 2 ]. EN = 11.38 MeV 2+ ion [(c) 64 pgfcm 2 ; (d) 0.8 pgfcm 2 ].
EN=28.81 MeV 3+ ion [(e) 32 pgfcm 2 ; (f) 0.7 pgfcm 2 ].

500

70

S. Kohmoto, et al.

coincide exactly. Even with carbon foil of 0.8
pg/cm 2 thickness, ions after passing through thefoil arrive at charge-equilibrium-state at .theseenergies. Mean charges at these energies are 4.7
and 5.4, respectively. When the incident energy isincreased up to 2 Me V/nucleon, ions reach .finally anon-equilibrium state as is shown in Fig. 1 (e) and(f). Peaks observed with thin carbon foil disappear
or diminish, with one exception, in the spectrumwith thick foil. These lines are believed to belong to
N IV or N V. As the mean charge at this energy is
about 6.4, the behavior of these peaks is reasonable.
The origin of the 390 nm line is not identified. 3)
A trial experiment was performed to measure
the relative Stokes parameter S/1 at EN= 28.81
MeV for the line N V (494 nm).

Thin carbon foil of 0.7 pg/cm 2 was tilted by 45°.
By using a rotatable )./4 plate, a linear-polarizer, anda depolarizer, we measured right- and left-handed
circular polarization, from which we estimated theS/1 value. Because of the limited beam intensity(about 0.2 pA) only rough estimation was made:
S/1 = 2± 6%. We plan to measure S/1 for the 341
nm line using optical elements of improved transmission in a short wavelength region.
References
1)
2)
3)

S. Kohmoto, M. Ishihara, T. Nomura, and Y. Gono:
RIKEN Accel. Progr. Rep., 17, 48 (1983).
H. Winter, P. H. Heckmann, and B. Raith: Hyperfine
Interactions, 8, 261 (1980).
J. DesesqueIles: These d'Etat, l'Universite de Lyon
(1970).

71
RIKEN Accel. Progr. Rep. 18 (1984)

111-2-14.

Beam-Foil Spectroscopy of Highly Ionized Aluminum Atoms
K. Ando, S. Kohmoto, T. Tonuma, H. Kumagai,
Y. Awaya, S. Tsurubuchi, and K. SatoAn experiment of beam-foil spectroscopy was performed to study aluminum spectra, which had beenscarecely observed in other facilities. 1 ),2)
Aluminum ion Al 3+ was accelerated up to 38
MeV, and was ionized and excited with a carbon
foil of 10 pg/cm 2• Its average charge was 10 andspectra of Al X, XI, and XII were observed. Assignment of spectral lines of each ions of Al X, XI, and
XII were made by comparing intensities at different
acceleration energies of 35.7, 22.5, and 15.1 MeV,
which corresponded to the average charge of 9.9,
8.8, and 7, respectively, after passing through thecarbon foil.
A spectrometer used was a grazing incidence typewith a 2.2 m diameter Rowland circle and 1,200
grooves/mm grating. Widths of an entrance andexit slit were 0.15 mm which corresponded to thespectral resolution of 0.56 A. The wavelength wasscanned by a stepping motor at 0.0075 inch/step,which corresponded to a wavelength step of 0.12
A at 100 A and 0.17 A at 200 A.
Figure 1 shows a spectrum observed for aluminum ions of average charge of 9.9 with identified+lines. These lines could arise from transitions between n=3 and n=4 by rough estimation of energy
values of levels. Wavelengths of spectral lines wereobtained to within an error of ±0.1 A from a calibration curve of second order polynomials calculated
from known spectral lines of Al X, XI, and XII asreferences.
For identification of spectral lines, we employed
an empirical formula by Edlen3) and estimated term
values of levels of d and f electrons of Li- and Helike ions. This formula is expressed as a sum ofhydrogenic term and polarization correction term.
Term values of other levels of Li- and He-likeions and of Be-like ion were estimated from a hydrogenic formula. Estimated term values are given in
Table 1 and the wavelengths calculated from Table
1 for interested transitions are given in Table 2.
Spectral lines due to the transitions of f electron
were observed to have strong intensities in thisexperiment for He- and Li-like ions, so that seriesof spectra of n= 5 and 6 for Al XI 2F and n= 5 for
Al XII 3F can be easily identified by comparing
with the calculated wavelengths. We also tried to~

1O

4.48 0

g

3.84
.
(J)

u)

r-...

0.64

Channel number

Fig. 1. Beam-foil spectrum of AI.
A13+, 35.7 MeV; equilibrium charge state, 10+.

K. Ando, et aZ.

72

Table 1.
Al XIIAl XI

Calculated term values.
1s4d
1S2sf
6f
7f
1s 22s5f
6f
1s 22p4f
Sf

AIX

Table 2.

Estimated wavelengths in A.
3p 3p - 4d
3p Ip - 4d
3d 2D - 5f 2F
6f 2F
2s3d 3D - 2s5f
6f
2s3d ID - 2s5f
6f
2p3d 3D - 2p4f
5f
2p3d 3p - 2p4f
Sf

Al XII
Al XI
AIX

T able 3.

Al XI

AIX

3p 3p 3p Ip 3p 2p 3d 2D 3d 2D 3d 3D -

127.3
130.8
105.8
90.3
123.4
105.9
127.6
109.0
183.7
126.4
187.0
127.9

Identified lines and energy values.

Identification
Al XII

15,836,800 cm- I
3,033,700 cm- I
3,196,000 cm- 1
3,293,900 cm- 1
2,775,800 em- 1
2,909,900 em- 1
2,704,800 em- 1
2,951,700 em- 1

4d 3D
4d ID
5d 2D
5f 2F
6f 2F
5f 3F

Wavelength
(A)
127.4
130.9
103.8
105.8
90.3
123.4

Level

Energyvalue(em-I)

4d 3D 3.2
4d ID2

15,836,700
15,836,400

Sf 2F2.5.3.5
6f 2F2.5.3.5
5f 3F4.3. 2

3,033,000
3,196,000
2,776,300

same transition by applying a theoretical term energy expreSSIOn,

E=Eav+A* GI (1s, 4d)where GI is the Slater integral calculated by the
Hartree-Fock method and A is an angular momentum term, which is 0.3 for 3D and 0.1 for ID. Fromthe measured 3D energy values, Eav was calculated
and E for ID state was 130.9 A. This line was observed by the side of a strong line of Al XII at 130.6
A. The identification of these spectral lines wereconfirmed from an iso-electronic sequence plot ofwavenumbers of these transitions against the net
charge of various ions.
The strong spectral line from 5f 3F to 3d 3D of
Al X was identified. The line from the transition of
the singlet term may have strong intensity, because
the line from 3F state has strong intensity. We tried
to estimate a wavelength of the singlet transition
from 5f IF to 3d ID by using the theoretical term
energy formula as mentioned above. It was estimatedas 187.0 A, but it was beyond the present measurement range.
Newly identified spectral lines and energy valuesof classified levels are given in Table 3.
As seen from Fig. 1, many strong spectral lines
still remain unidentified. These spectral lines may
arise from doubly excited states of Al XI (Li-like)and Al X (Be-Like). The transition energies fromthese highly ionized atoms have not been calculated
theoretically so far.
References

identify the spectral lines from 4d 3D and I D of
Al XII. The estimated term value of level of 4delectron is an average of the term values of the 3D
and I D states, but it is close to that of the 3D states
because a weight of the 3D state is larger than thatof the I D . We can identified the spectral line from
3D state. We tried to identify a singlet state of the

1)

2)
3)

B. Denne, D. J. Pegg, K. Ishii, E. Alvarez, R. Hallin, J.
Pihl, and R. Sjodin: ]. Phys. (Paris), 40, Call. 1, 183(1979).
B. Denne, S. Huldt, J. Pihl, and R. H allin: Phys. Scr.,
22, 45 (1980).
B. Edlen: Encyclopedia of Physics, (ed. by S. Flugge),
Springer-Verlag, Berlin, Vol. XXVII, p. 125 (1964).

73
RIKEN Accel. Progr. Rep. 18 (1984)

111-2-15.

Intensity Ratio between K,8 and Ka X-Rays from33 MeV Ar Ions in Solid Targets

T. Kambara, Y. Awaya, M. Kase, H. Shibata, and H. Kumagai

We have been measuring K X-rays from Ar ionspassing through various solid targets with highresolution to study target atomic number (Z2) dependence of multiple inner-shell ionization process.
We have reported that the L-shell ionization probability of the Ar ions (Pd at the time of the Ka
transition and the hypersatellite to satellite intensity
ratio of the Ka X-rays depend on the target atomic
number (Z2) systematically.1),2) In the present
report, we present the result of measurement of therelative intensity of the K .a X-rays to the Ka X-rays
as a function of Z2. Although preliminary data were
presented in the last issue of this report,3) we havemade measurements for more sorts of target species
and found that the ratio has a dependence similar tothat of PL' This implies that the electronic transition from the outer shell is affected by the ionizationin the L-shell.
Ka -S a tellites

Ka HyperSatellites

The experimental set up is the s~me as that reported previouslyl); the energy 'o f the incident Ar
ions from the linac is about 33 MeV and the X-rays
are measured by a broad range crystal spectrometer.
The target species are Be, C, Mg, AI, Ca, Ti, Cr, V,
Fe, Co, Ni, eu, Zn, Y, Nb, Tb, Ta, and Au. Some
examples of the X-ray spectra are shown in Fig. 1.
In the spectra, the Ka satellites, the Ka hypersatellites and the K .a satellites are observed from theleft- to right-hand side. In order to assign the Lshell hole numbers for the K.a satellite peaks, theresult of energy calibration using fluorescent L Xrays of In and Sn is compared with the estimatedvalues of K transition energies.
The L-shell ionization probability at the time ofK a transition is deduced from the intensity distribution of the K a satellites, as reported previously,1),2) and it shows oscillatory dependence on
Z2 with the first minimum at Z2= 22 and the second
one at Z2=4S. This dependence is shown in Fig.
2 (a), where the ionization probability is denoted by
P L (Ka). This fact is described as a result of level
matching between the L-shell of Ar ion and the L-

0 .5

10 3

Zn Target

~
~

~

0.4

10

(\

(a)

;~I\
.J..; \
-'t

.-I
0)

c::
c::

Ti Target

'"

..c.:

u

~

"Ul
.j.J

c::

;:l

0.7

~ 0.6

10

0

u

'\)~.~
..
.

0.4

(c)

10 3

0.3
~

.~

']

0.2

Cl::i..

~

I

3.4 keV

10 2

!

!

256

512

Channel Number

Fig. 1. Examples of K X-ray spectra from 33 MeV Ar ionspassing through various targets.

0.1
0.0

(b)

I\!\/\.~ ..
\,o 10 20 3040 50 60 70 8090

Zz
Fig. 2. The target atomic number Z2 dependence of (a)probability of L-shell holes at the Ka X-ray emission, (b)probability of L-shell holes at the K p X-ray emission, and(c) intensity ratio between Ar Kp X-rays and Ka X-rays.

74

T. Kambara, et al.

and M -shell of target atoms. The ionization probability at the time of K,a transition, P L (K,a), estimated from the average energy of the Kp satellites,
is shown in Fig. 2 (b). It has the same dependence
as that of the P L (Ka) on Z2 at small Z2'S but thedependence is not clear at large Z2'S. The firstminimum is seen in both Ka and K,a transitions but
the second one is not clear for K,a one.
The intensity ratio among the Ka satellites, Ka
hypersatellites, and K,a satellites is strongly dependent on the target species. The Z2 dependence of theintensity ratio between Ka satellites and the Ka
hypersatellites has been discussed previously,l),2)
The Z2 dependence of the intensity ratio between
the Kp and Ka X-rays, shown in Fig. 2 (c), issimilar to the Z2 dependence of the ionization probability P L (Ka) shown in Fig. 2 (a). This may be

explained as a result of the increase in electron
capture cross section to M -shell according to thelevel matching and increase in the transition probability of the K,a transitions for ions with more Lshell holes if the number of electrons in the M -shellis independent of the number of L-electrons. Further analysis is in progress.
References
1)

2)

3)

Y. Awaya, T. Kambara, M. Kase, H. Kumagai, J.
Urakawa, H. Shibata, T. Matsuo, J. Takahashi, and M.
Namiki: RIKEN Acee!. Progr. Rep., 17, 49 (1983).
Y. Awaya, T. Kambara, M. Kase, H. Shibata, H. Kumagai, K. Fujima, J. Urakawa, T. Matsuo, and J. Takahashi:
Nucl. Instrum. Methods, BI0, 53 (1985).
T. Kambara, Y. Awaya, M. Kase, H. Kumagai, S. M.
Shafroth, H. Shibata, and T. Tonuma: RIKEN Aeeel.
Progr. Rep., 17, 51 (1983).

75

RIKEN Accel. Progr. Rep. 18 (1984)

111-2-16. High Resolution Measurement of Cu K X-Rays from Collision
Systems of Cu Ions on C Target and C Ions on Cu Target
Y. Awaya, T. Kambara, M. Kase, H. Shibata,
H. Kumagai, M. Nishida, and K. Shima

We have studied target atomic number Z2 dependence of an average L-vacancy fraction P L , thatof the intensity ratio of Ka hypersatellites and Ka
satellites I(Kha)/I(Ka) and that of K.a and Ka
X-rays I(K.a)/I(Ka) as to the K X-rays from Ar
ions passing through various kinds of target foi1. 1) - 4)
The Z2 dependence of P L has been discussed andexplained from the viewpoints of electron capture
and loss processes during creation and filling of theK vacancy of Ar ions accompanying multiple Lshell vacancies and that of I(Kha)jI(Ka) from therotational coupling of 2p1l'-2pn and 3d1l'-3dn ofmolecular orbitals formed by collision partners.
In order to study the difference in ionized states
between target atoms and projectile ions, we havemeasured the K X -rays from the Cu ions passing
through C foil and that from Cu target atoms excitedby C ions under the conditions that the target atoms
and the projectiles have the same relative velocity.
The 0.83 MeV /amu Cu4 + and C2+ ions wereaccelerated by the linac and momentum analyzed.
Targets used were 80 pgjcm 2 carbon foil for Cu ionsand 0.2 mgjcm 2 Cu foil for C ions. The Cu K X-rays
were measured by using a broad range X-ray crystal

Cu X-rays
1000

0.83 MeV/amu
Cu ion - C

0

f/)

C
::J

0

0

0.83 MeV/amu
Cion - Cu

500

o

..J

,...

..J

:.:: :.::
0

;

2000

c-.

:.::

X ray tube

tI

:.::

~
(Q.

:.::

0 7 •6

8.0

8.4

8.8

9.2

Energy (keV)

Fig. 1. Spectra of Cu K X-rays from projectile Cu ions passing through C foil and fromtarget Cu foil induced by C-ion bombardment. Fluorescent Cu X-rays are also shownfor comparison. The incident energy of Cu ions and C ions is 0.83 MeV/amu.

76

Y. Awaya, et al.

spectrometer5) with a crystal of LiF (220) (2d =2.848 A).
An estimated value of the average charge of incident Cu ions is 17.3+ 6) and Cu ions are considered
to reach a charge equilibrium state after they traverse the carbon target of a few p.g/cm 2 • This meansthat if a Cu ion loses their electrons successively
from low to high binding energies, the ion does notbear L vacancies when it collides with a target C
atom. Therefore, the configurations of Land K
shells are considered to be nearly the same for the
projectile Cu ion and the target Cu atom. On theother hand, the effective charges felt by a projectile
Cu ion from a target C atom and that felt by a target
Cu atom from a projectile C ion is deemed to be 6+
when a K electron of Cu ion/atom is ionized. The
difference between the spectra of Cu K X-rays fromthe projectile Cu ions and that of the target Cu
atoms reflects mainly the density effect in collisionsystem.
The Cu K X-ray spectra obtained from Cu ionsand the Cu target are shown in Fig. 1 in comparison
with the fluorescent Cu X-rays. KLn denotes theinitial state vacancy configuration with single K andn-multiple L holes. Figure 1 shows that a Cu ion
has about two more L vacancies than a target Cu
atom when K X-rays are emitted. This is because a
Cu ion collides successively with target C atoms

whereas a target eu atom interacts once with aprojectile C ion during the K vacancy exists. Whena projectile loses one K electron and multiple L
electrons in a collision with a small impact parameter, then it can collide with other target atoms
with larger impact parameters and captures or loses
outer shell electrons before K X-rays are emitted.
Further measurements of Cu K X-rays from boththe projectile Cu ions and the target Cu atom excitedby carbon at the different collision energies will
provide more information about the collision processor the state of the Cu projectile and the atom;studies are in progress.
References
1)

2)
3)
4)

5)
6)

Y. Awaya, T. Kambara, M. Kase, H. Kumagai, J.
Urakawa, H. Shibata, T. Matsuo, J. Takahashi, and M.
Namiki: RlKEN Accel. Progr. Rep., 17,49 (1983).
T. Kambara, Y. Awaya, M. Kase, H. Kumagai, S. M.
Shafroth, H. Shibata, and. T. Tonuma: ibid., p. 51
T. Kambara, Y. Awaya, M. Kase, H. Shibata, and H.
Kumagai: p. 73 in this report.
Y. Awaya, T. Kambara, M. Kase, H. Shibata, H. Kumagai, K. Fujima, J. Urakawa, T. Matsuo, andJ. Takahashi:
Nucl. Instrum. Methods, B10, 53 (1985).
A. Hitachi, H. Kumagai, and Y. Awaya: ibid., 195, 631(1982).
K. Shima, T. Ishihara, and T. Mikumo: ibid., 200, 605(1982).

77
RIKEN Accel. Progr. Rep. 18 (1984)

111-2-17.

REC X-Rays for 3He and 4He Targets

T. Kambara, Y. Awaya, M. Kase, H. Kumagai,
H. Shibata, and T. Tonuma

In order to study target isotope dependence ofthe cross section of radiative electron capture(REC), we have measured energy spectra and yieldsof X-rays from the REC process induced by 110
MeV Ne-ions incident on target of 3He and 4He
isotopes. Theoretical features of the isotope dependence are discussed in this report.1,2)
The experimental set-up was almost the same asthat reported elsewhere. 3) A beam of 120 MeV
N e6 +-ions from the cyclotron passed through a gas
cell after it was defined by a 1 mm-wide slit, and thenreached a Faraday cup. The target He gas was contained in the gas cell at pressures up to 240 Torr.
The pressure was measured by a baratron gauge andset to the same value for the two isotopes. The energy of the Ne-ions are estimated to be about 110
MeV in the gas cell and most of them are considered
to be bare (10+) or H-like (9+); therefore theelectrons of the target gas can transfer to a K -shellvacancy of the Ne-ion through the REC process.
The X-rays emitted from the collision volume
passed through a 4 pm-thick Mylar window of thegas cell and were detected by a Si (Li) detector
placed at 90° to the beam direction. The X-ray path
between the gas cell and the detector was evacuatedin order to minimize the absorption of the X-rays.
Examples of the observed X-ray spectra for theboth isotopes are shown in Fig. 1. Both spectra wereobtained at the same target gas pressure of 240
Torr and with the same amount of the integrat'ed
beam current. In the spectra, the peaks at about 1
keV correspond to the characteristic K X-rays fromthe Ne-ions and one at about 4 keV to the REC
X-rays. No difference was observed between the
X-ray spectra and REC X-ray yield for the twoEnergy (keV)r.-:---=2"T.O=----=-4;-::.0--,6,...::,0--=8:.r' O~ 1O~

10 4

10 3

3

...0

:0
':::' 10 3
.2

10 ~
2

Q)

c
c

C

J::

co

C

J::

~
~
10 1 c

2C

0
()

co

~ 10 2

:J

:J

0
()

10 1

10°

Channel number

Fig. 1. Energy spectra of X-rays from collisions between
110 MeV Ne-ions and He gas targets at about 240 Torr:(a) for the 4He and (b) for the 3He. Peaks at about 1 keVare
Ne K X-rays and one at about 4 keV is REC X-rays to a Ne
K-shell vacancy.

isotopes. It was concluded that the difference in the
REC cross section between the two targets should
be within 7%.
References
1)
2)
3)

K. Hino, I. Shimamura, N. Toshima, and T. Watanabe:
p. 62 in this report.
K. Hino, I. Shimamura, and T. Watanabe: p. 64 in thisreport.
T. Kambara, Y. Awaya, A. Hitachi, M. Kase, I. Kohno,
and T. Tonuma : J. Phys. B, 15, 3759 (1982).

78
RIKEN Accel. Progr. Rep. 18 (1984)

111-2-18.

Production of Highly-Charged Slow Ar Ions Recoiled In
1.05 MeV amu - 1 Ar q + (q= 4, 6,10-14) Ion Bombardment
T. Tonuma, H. Shibata, S. H. Be, H. Kumagai,
M. Kase, T. Kambara, I. Kohno, and H. Tawara

The charge-state distribution of slow recoil ionsproduced in collisions of 1.05 MeV amu- 1 Arq +(q=4, 6, 10-14) ions with Ar target atoms has beenmeasured. Combining these charge-state distribution
data with absolute values of total ionization crosssections measured through a parallel-plate method,l)we determine the absolute partial cross sections forthe production of recoil Ari+ ions.
In Fig. 1 the total apparent cross section (~iO';)and the partial cross sections (0';) for production ofrecoil Ari+ ions produced in Arq + ion impact areplotted against the projectile charge state q. Generally speaking, the total cross sections for production of the recoil ions and also the yields of eachcharge state of recoil ions increase with increasing
charge of projectile ions q.2) In particular, the highly
charged recoil ion production is enhanced significantly in high charge projectile ion impact.Olson 3)
calculated the cross section 0'; for ejecting i electrons
in the M-shell based upon the classical trajectoryMonte Carlo (CTMC) method. Dotted lines inFig. 1 represent his results of calculation for projectile energy of 1 MeV amu- 1 . The values of thetotal ionization cross sections (~O'i) calculated by the
CTMC method are in agreement with the present
results. The present measurements and calculationsof the total apparent ionization cross sections (~iO'i)
are in accord with each other to within a factor of
2 for a wide variety of projectile charge states though
the dependence of the cross sections on the projectile
charge q is slightly different from each other. The
theoretical partial ionization cross section, however,is underestimated for small i and overestimated forlarge i.
The partial ionization cross sections 0'; with ihigher than 8, where the L-shell electrons are to be
ionized, increase with the projectile charge stage q.
The partial ionization cross sections 0'; (i ~ 9) are
analyzed in terms of the ionization probability based
upon the independent electron model. The probability Pm+l for ionization of m electrons in the Mshell and simultaneously I electrons in the L-shellamong 8 electrons in each shell of Ar atom, corresponding to i=m+l, in collisions with an impact
parameter b, is given by:

P m+/(b)=Pm(b) P/(b)where

Pm( b)= (~) (PM( b))m(l - PM(b))8-m
Pl(b) = (~)(pdb))/(1-pdb))8-1

and (~) and (~) are the binomial coefficients and PM(b) and pdb) represent the ionisation probabilities ofa single electron in the M- and L-shells, respectively.
In the simplest case, PM(b) and pdb) can be assumed
to be constant within the critical impact parameters.
As far as the production of slow recoil ions withi ~ 9 is concerned, all eight electrons in the M -shell
can be assumed to be ionized in the present Arq ++Ar collisions, that is, Pm is independent of the ionization of the target L-shell electrons. Then, thedependence of the relative values of P s+/ on the
charge state of the projectile ions is represented only

Fig. 1.

Total apparent cross section :2JiO"i, total cross section:2JO"i, and partial cross section O" i for production of therecoil Ar H ions as a function of the projectile charge q of
1.05 MeV amu- 1 Arq+. Dotted lines represent the results
calculated by Olson for the projectile energy of 1 MeV
amu- 1 .

T. Tonuma, et al.

0.22 . - - - - - - - - - - - - - ,0.20/e/~ 0.18~ 0.16~ 0.14~ ~:~~

5,-~,--~,-~,~,~. -~--~,-,~

§

o

0.02

I -

crQ 4

e/e

><

/

.03

/e

\...

~

E 2 --------------------------------E/e.2 0.08 r-e--f----./~ 0.06'c 0.04

79

o

0..

-

-u 1
8.
E

~

Number o.f L-shell vacancies

o 1 2 3 4 5 60

Projectile charge state q,

Fig. 2. Ionization probability PL of the L-shell electrons of
Ar atoms plotted against the projectile charge state q in
1.05 MeV amu- 1 Arq++Ar collisions.

by PI! which can be determined by a least-squares
fitting to the experimental data. 4) Figure 2 displays aplot of the obtained probabilities PL against the projectile charge state q. It is found from Fig. 2 that theprobabilities PL for impact of projectiles with charges
q=4-6 are independent of the charge state q, but
increase significantly for higher projectile charge
state q= 10-14, which corresponds to the projectiles
with two to six L-shell vacancies. By interpolatingthese results, it is concluded that the ionization isstrongly enhanced once the projectile L-shell vacancies are brought into collisions. This enhancement is believed to be due to electron transfer fromtarget atoms into the L-shell vacancies of projectiles.
The inner-shell electron transfer of the target atoms
contributes significantly to the production of slow,
highly charged recoil ions in the high-energy heavy
ion impact.
The ionization probability PL can be assumed tobe constant within the critical impact parameter be
and zero otherwise, that is, PL is a step function.
Therefore, the partial ionization cross section, (18+1,of the recoil ions is given by (18+1= ~:CP1(b) 2n- b db.
The critical impact parameter be can be determinedfrom the experimental data of (18+1 and the estimated values of PL in Fig. 2. In Fig. 3 be values
thus determined are plotted as a function of the
projectile charge state q. Figure 3 shows that thevalues of be for projectiles with q= 4-6 increaseslightly with q and are smaller than 2.3 X 10-9 cm
expected from the orbital radius of the L-shellelectron of the Ar target. The orbital radius is given
by aL=aOn 2 jZ, where ao=0.529x 10- 8 cm, n designates the principal quantum number of the electron
shell, and Z is the effective nuclear charge at that

r

I

I

I

I

r

Projectile charge state q

O~~~~~~~~~~~~

3 4 5 6 7 8 9 10 11 12 13 14

1

0~-72---4~-6~~8~~10~~1~2--~14~

Fig. 3. Critical impact parameter be of the L-shell of Ar
atoms plotted against the projectile charge state q in 1.05
Me V amu- 1 Ar q+ + Ar collisions. The dotted line represents
expected values for the orbital radius of the L electron shellof Ar target.

shell. On the other hand, be increases significantly
for high projectile charge state of q= 10-14 and ismuch larger than the expected value of av It isfound that the critical impact parameter for the Lelectron shell increases significantly once the projectile L-shell vacancies are brought into collision,
resulting in a similar trend to the ionization probabilities described above. This result shows that,in the 1.05 MeV amu- 1 Arq+ (q~6) ion impact the
production of recoil Ar i + (i ~ 8) ions occurs at
distances slightly shorter than the radius whereas,in the Arq + (q~9) ion impact at fairly large distances which increase with the projectile charge,
indicating that the ionization mechanisms in Arq+(q~8) and Arq + (q~9) ion impact are quite different from each other. A similar increase in thecritical impact parameter in the ionization processes
in impact of high q ions with the inner shell vacancies
has already been reported by Hagmann et ai.,5)
suggesting that the electron capture into projectiles(L-shell) from a target atom (L-shell) plays a rolein the production of highly charged recoil ions in
the present work.
References
1)

2)
3)
4)

5)

S. H. Be, T. Tonuma, H. Kumagai, H. Shibata,
M. Kase, T. Kambara, I. Kohno, and H. Tawara: p. 80,
in this report.
C. L. Cocke: Phys. Rev. A, 20, 749 (1979).
R. E. Olson: J. Phys. B: At. Mol. Phys., 12, 1843
(1979).
T. Tonuma, M. Kase, T. Kambara, H. Kumagai, T.
Matsuo, J. Urakawa, H. Shibata, J. Takahashi, S. ()zkok,
S. H. Be, I. Kohno, and H. Tawara,j. Phys. B: At. Mol.
Phys., 17, L317 (1984).
S. Hagmann, C. L. Cocke, J. R. Macdonald, P. Richard,
H. Schmidt-Bocking, and R. Schuch: Phys. Rev. A, 25,
1918 (1982).

80
RIKEN Accel. Progr. Rep. 18 (1984)

111-2-19.

Total Apparent Cross Sections for Ionization of Rare-Gas
Atoms by Fully Stripped Projectiles

S. H. Be, T. Tonuma, H. Kumagai, H. Shibata,
M. Kase, T. Kambara, I. Kohno, and H. Tawara

In this report we present the results of the total
apparent cross sections for ionization of rare-gas
atoms by fully stripped projectiles. Further, theresults are discussed in connection with the calculation of 0lson1) based on the classical trajectoryMonte Carlo (CTMC) method with special emphasis on dependence on Z.
Experimental results for total apparent cross sections for ' ionization of He, N e, and Ar targets by
1.05 MeVJamu fully stripped He 2 +, 0 6+, 0 8+, andNe lO + projectiles are given in Table 1. Figure 1
shows plots of measured cross sections versus theatomic number of fully stripped projectiles. Target
atom is indicated on each curve. The solid lines
show a least-squares fit of the present experimental
cross 'sections including those of Rudd et al. 2) toa function O'+=O'oZa, where a= 1.84 and 0'0=
0.23 X 10-16 for He target, a= 1.69 and ao=0.61 X
10-16 for Ne, and a= 1.68 -and 0'0= 1.52 X 10-16 forAr. The results of Schlachter et al.,3) Hvelplund
et al.,4) and Knudsen et al. 5) for the cross sections
are also included in this figure. The results of
Schlachter et al. are for ionization of He, N e, andArtargets by C6+ projectile of 1.14 MeVJamu, andthose of Rudd et al. are for H + incident on He, N e,
and Ar targets at 1 MeV Jamu. The results ofHvelplund et al. for 0 8 + incident on He target at
1 MeVJamu represent the sum of the single- anddouble-electron ionization cross sections, which isthe sum of the number of electrons ejected duringcollision weighted by the individual cross section foreach event. The results of Knudsen et al. are for
Table 1. Total apparent ionization cross sections, a+, inunits of 10-16 cm 2 • Projectile ion energy is 1.05 MeVjamu.
TargetProjectile
He 2+
C6+

0 8+
Ne 1O +

He

Ne

Ar

0.83+0.06-0.04
7.2+0.6-0.3
10.0+0.8-0.4
14.4+ 1.0
-0.6

2.0+0.2-0.1
13.2+1.0
-0.6
20+2
-1
29 + 2.3-1.3

5.0+0.4
-0.2
32+3
-1
51 +4
-2
71 +6
-3

H+, He 2+, Li 3+, B5+, C6+ and 0 8+ incident on He
target. These plotted points of Knudsen et al. wereobtained by extrapolating the curve of the crosssections as a function of projectile energy and are
the sum of the single- and double-electron ionization
cross sections. As seen from Fig. 1 these experimental data obtained by other groups fall nicely
on our experimental curve and are in excellent
agreement with our results except the cross sectionof Schlachter et al. for ionization of N e target by
C6+ projectiles. Even for this case, the results agree

Fig. 1. Total apparent cross sections for ionization of targets
by the fully stripped projectiles. The open circles are thepresent experimental results for He 2+ (Z=2), C6+ (Z=6),0 8+ (Z=8), and Ne 10 + (Z=10) projectiles of 1.05 MeVj
amu; the closed circles are experimental results of Rudd
et al. (Ref. 2) for H+ projectiles of 1 MeV; the closed triangles
represents experimental results of Schlachter et al. (Ref. 3)
for 1.14 MeVjamu C6+ projectiles; the closed squares
shows experimental results of H velplund et al. (Ref. 4) for
1 MeV /amu 0 8 + projectiles; the asterisks are experimental
results of Knudsen et al. (Ref. 5) for H+, He 2+, Li 3+ B5+,
C6+ and 0 8 + projectiles of 1 MeV/amu; the solid lines
show a least-square fit of the present experimental crosssections to a function a+=aoza, where Z is the atomic
number of fully stripped projectiles; the dotted lines represent the CTMC calculation of Olson (Ref. 1).

S. H. Be, et al.

with our data within 20%'
It is interesting to compare our experimental datawith the CTMC calculation (dotted lines in Fig. 1)
by Olson. Generally, the calculation is in agreementwith the present results except for those of N etarget. Even for the case of the N e target, the agreement is not too bad if the overall accuracy of ± 50%
for ionization of the Ne target, given by Olson istaken into account.
However, there exists a clear difference in theZ-dependence of the cross sections; the calculated
cross sections tend to increase approximately withthe square of the charge state of the projectile (a=2),
with a slightly lower dependence at high Z, whilein our case a= 1.7 for Ne and Ar targets, and a=
1.84 for He target. Although our best fit parameter afor the cross sections with the Z are slightly different from the calculation by Olson, our results
agree well with the Z-dependence for Bohr parameter K> 1 as discussed by. Knudsen et al. who
pointed out that for the perturbation region (K> 1)
the cross section is proportional to Z2, in agreementwith perturbation theory, but for K> 1 correspond-

81

ing to our case, namely, in the strong-interaction
region the dependence on Z becomes weaker.
Here K=2Zvo/Vj, where Vo is the Bohr velocity
and Vj is the projectile velocity.
In conclusion, our results are generally in agreement with the calculation of Olson except for thatof N e target, but our scaling laws for the crosssections with the charge state are found not to follow
the Z2 law predicted by the calculation. However,
our results 'agree well with experimental Z dependence by Knudsen et ai.
References
R. E. Olson:]. Phys. B, 12, 1843 (1979).
M. E. Rudd, R. D. DuBois, L. H. Toburen, C. A. Ratcliffe, and T. V. Goffe: Phys. Rev. A, 28, 3244 (1983).
3) A. S. Schlachter, K. H. Berkner, W. G. Graham, R. V.
Ryle, P. J. Schneider, K. R. Stalder, J. W. Stearns, J. A.
Tanis, and R. E. Olson: Phys. Rev. A, 23, 2331 (1981).
4) P. H velplund, H. K. Haugen, and H. Knudsen: Phys.
Rev. A, 22, 1930 (1980).
5) H. Knudsen, L. H. Anderson, P. Hvelplund, G. Astner,
H. Cederquist, H. Danared, L. Liljeby, and K-G.
Rensfelt: J. Phys. B, 17, 3545 (1984).
1)
2)

82

RIKEN Accel. Progr. Rep. 18 (1984)

111-2-20.

Production of Highly-Ionized Recoil 10ns in Highly-Ionized,
Energetic Ion
Molecule Collisions+

H. Tawara, T. Tonuma, S. H. Be, H. Shibata,
H. Kumagai, M. Kase, T. Kambara, and 1. Kohno

In the course of investigations on the production
impact parameters, we can see a number of peaks
mechanism of highly-ionized recoil ions in highlycorresponding to highly-ionized nitrogen ions (Ni+)
ionized heavy ion impact, we have already describedwith a weak trace of N6+ ions. As we used 14N2 gas
some of recent results which indicate the significant
molecules, we could not distinguish N7+ ions fromcontribution of electron capture processes to the proHz + ions because both have the same m/i (mass toduction of such recoil ions when the innershell vacharge ratio) values. It is clearly seen from thesecancies of the projectiles are brought into collisions.!)
spectra that, with increasing the projectile charge q,
We have also measured the production cross sections
the production of highly-ionized recoil ions such asof highly-ionized recoil Ar i + ions in Arq + (q=4, 6,
N4+, N5+, and N6+ ions are significantly enhanced.
10-14) ion impact. 2)
I t is interesting to compare these data with thoseIn the present experiment is used an apparatus
in electron impact. However, very few measurements
similar to that previously described 2) with someof the cross sections of production of highly-ionized
modification. To reduce the energy spread of recoil
recoil ions from molecular targets by electron impact
ions due to the extraction field, we used relatively
have been reported. Up to now, N3+ ions are theweak extraction field of 40 V applied to two parallel
highest charge state directly observed in electron
plates apart 1 cm and then accelerated the ions at
impact whose production cross sections have been
1.5 kV. Typical charge spectra of recoil ions from
reported to be of the order of 10- 23 cm2 at 240q
N2 molecules in 1.05 MeV/amu Ar + (q=4, 12)eV.3) Ratios of ions with different charge state inion impact are shown in Fig. 1. In these spectra, in
240 eV electron impact and 1.05 MeV /amu Ar12+
addition to dominant singly-ionized molecular ionsion impact are as follows:
N z+ which are produced in soft collisions with large
N+
N2+
N 2+
N 22+
N6+
N3+
N4+
N5+
2
7
2
1.7 x 102.6 x 10-1
1.2 X 101.3 X 10electron
1.0
Ar12+
3.1 X 10-1
4.4 X 10-2 9.0x 10-3 1.5 X 10-3
1.0
5.3 X 10-4 some
In a comparison of these data, the production crosssections of N3+ ions in electron impact reported by
Daly and Powell seem to be too small, even if there
seems a significant difference in production ofhighly-ionized recoil ions in electron and ion impact.
Production of N 2+ and N 22+ (which is not separated
from N + ion in the present work) ions is due todistant collisions with small momentum transfer
and is apparently similar to that in single atom ionization. Mechanisms responsible for production ofhighly-ionized atomic recoil ions from moleculartargets is expected to be different from those insingle atom targets. The question is whether thesehighly-ionized atomic recoil ions from molecul'ar
targets are produced in ionization processes followedby dissociation or dissociation processes followedby ionization. The collision time in the present
system (projectile velocity~ 1.4 X 109 cm/s, molecular bond length~ 1A) is estimated to be of theorder of 10-17 s, which is much smaller than the

dissociation time of molecules (~1 0- IL 10-15 s),though no direct measurement of the dissociation
time of nitrogen molecules N z has been reported
yet. Therefore, these highly-ionized atomic recoil
ions are believed to be produced through highlyionized molecular ions followed by dissociation into
two (or more) highly-ionized atomic ions. In electron
impact, only singly- and doubly-ionized molecularions (N 2+ and N 22+) have been observed but nomolecular ions with higher charge. Even in thepresent work there is no trace of triply-ionizedmolecular ions (N 23+) with m/i=9.33 observed.
This may be due to the fact that these highly-ionizedmolecular ions, probably in highly excited states,
are not detected because their life time are too shorteven if they are produced in collisions. In fact,
the intensities of N 22+ ions in electron impact are
only 1-2% of those of N 2 + ions. This is quite incontrast with the fact that the intensities of doublyionized Ar2+ ions (which have similar binding

H. Tawara, et al.

Nt

104

Channel number

Fig. 1. Typical charge spectra of nitrogen ions produced in
1.05 MeV/amu Ar q+ (q = 4, 12) ion impact on molecular
nitrogen N2.

energy as of N 2 molecules) is as much as 5-6% of
Ar+ ions. Therefore, such highly-ionized molecularions are easily dissociated into highly-ionized atomic
ions. These highly-ionized molecular ions are assumed to be less likely to dissociate into ions withvery asymmetric charge but much likely to do into
ions with relatively symmetric charge distribution.
Also it is unlikely that low charge state molecularions dissociate into highly-ionized atomic ions.
Therefore, the highly-ionized atomic ions, for example N5+ ions, are probably produced via highlyionized molecular ions through the following puredissociation processes (for example):N 29+ --+ N5++N4+
N 210 + --+ N5+ + N5+
N 211 + --+ N5+ + N6+
or the dissociation into highly excited atomic states

83

followed by electron emission:
N 28+ --+ (N4+)*+N4+ --+ N5++ e +N4+
These processes are a few examples of the possible
dissociation processes.
If the production of highly-ionized atomic recoil
ions are assumed to be due to the dissociation (Coulomb explosion) of highly-ionized molecular ions,as discussed above, the product atomic ions shouldhave some kinetic energies due to the Coulomb force
between the dissociated atomic ions (the ions withhigher charge have higher kinetic energy), compared with those molecular ions such as N 2+ andN 22+. These highly-ionized product ions could beassumed to be isotropically distributed with respectof the incident ion direction at the present impact
energy. Then, the 100% collection of these productions through a hole in the parallel plates and acceleration system should be quite difficult. Therefore,
when a comparison is made of relative yields ofdifferent ions produced in molecular targets, careshould be exercised for overall collection efficiencyof these ions.
Information such as the energy levels and their
lifetimes of highly ionized molecular ions, for example N 210+ ions, as well as accumulation of experimental data could be relevant to further understanding the production mechanism of highly
ionized ions from molecular targets.
References
1)

T. Tonuma, M. Kase, T. Kambara, H. Kumagai, T.
Matsuo, J. Urakawa, H. Shibata, J. Takahashi, S. Ozkok,
S. H. Be, I. Kohno, and H. Tawara:}. Phys. B, 17, L317
(1984).
2) T. Tonuma, H. Shibata, S. H. Be, H. Kumagai, M. Kase,
T. Kambara, I. Kohno, and H. Tawara: unpublished(1985).
3) N. R. Daly and R. E. Powell: Proc. Phys. Soc., 89, 273(1966).

84

RIKEN Accel. Progr. Rep. 18 (1984)

111-2-21. Projectile Dependence of L-M M Auger Electrons
Ejected from Ar Target by Heavy-Ion Impact
H. Shibata, T. Matsuo, Y. Awaya, T. Kambara,
M. Kase, H. Kumagai, and N. Tokoro

We have measured the · energy distributions ofejected electrons in Ar 3,4++ Ar collisions with ahigh energy resolution in order to study the ionization mechanism in heavy-ion atom collisions andthe energy levels of highly ionized atoms. L23-MIMI
Auger electrons from highly ionized target argon
atoms, such as Ar 7+, Ar 6+, and Ar 5+, have been
observed, which appears when 3p ionization occurs
simultaneously with 2p ionization'!)In the present report, we present preliminary results of the projectile and charge state dependencesof the L 23-MM Auger transitions of Ar. Though it is
known that the normal L 23-MM Auger lines appear

strongly in the electron or proton impact (see Fig. 1),very few experiments have been made in the heavyion impact to study how the degree of the ionization
increases as the atomic number of projectile increases. The spectra of the L 23-MM Auger electronsejected from an Ar target by about 1 MeVjamu He,
C, N, and Ar ion bombardments have been measured at an ejected angle of 135 0 with respect to thebeam direction. He+, C2+, N2+, and Ar 4+ ions wereaccelerated by the RILAC and He 2+, C5+, and N6+ions were produced by passing ions through acarbon foil stripper. The other experimental conditions and apparatus were described elsewhere. 2)

4.48 MeV He+Electron energy (eV)Fig. 1. Energy spectra of electrons ejected from target argon atoms at 135° from the beam
direction by about 1 MeV/amu He+, C 2+, N2+, and Ar 4 + ion impacts and that by electron
impact. The lines above the spectra indicate the calculated energy values for the corresponding transitions denoted on their right hand side. The number of each line shows
the number of 3p vacancies in the initial state of Auger transition.

85

H. Shibata, et al.

15.2 MeV N"'+ on Ar

240
Fig. 2. Energy spectra of electrons from target argon atoms produced by 15.2 MeV N2+
and N6+ bombardments. The number in the parenthesis of L - MM notation indicatesM23-shell (3p) vacancies in the initial state of the Auger transition.

The ejected electron spectra obtained by He+,
C 2+, N2+, and Ar 4 + impacts are shown in Fig. 1
together with a 3.0 ke V electron impact data for thecomparison. The energy range of electrons was from80 to 250 eV. The lines above spectra in Fig. 1
indicate L 23-MM Auger electron energies calculated by Larkins 3) using the adiabatic model. The
number of each line indicates the number of 3p
vacancies in the initial state of Auger transition.
We have compared the spectra with the theoretical
calculations and obtained the following results.
In the case of He+ impact, the normal Auger lines,
L23-M23M23, L23-MIM23, and L 23-M 1M 1, appearedstrongly and they are very similar to the case of electron impact. However, as the atomic number Z of the
projectiles increases, the normal Auger lines weakened and the intensities of satellite lines enhanced.
Namely, for Ar impact the normal Auger lines
disappeared completely and the intensities of theAuger lines from the charge states of 7 +, 6 + and 5 +of Ar increased.
Figure 2 shows an example of the charge state
dependence of the projectiles having the same

velocity. A drastic change is seen between N2+ andN6+ ion bombardments. For N2+ impact the normal
Auger transitions were clearly observed; on theother hand, for the case of N6+ the normal transitions
diminished and satellite lines from the highly ionizedatoms enhanced. This may be attributed to the 3p
electron transfer from target to projectile, because
the one-electron transfer cross section from thetarget to N6+ ion has about two orders of magnitudelarger than that for the case of N2+ ion. 4 )Further systematic measurements and analysis
are in progress.
References
1)

2)

3)
4)

T. Matsuo, H. Shibata, J. Urakawa, A. Yagishita, Y.
Awaya, T. Kambara, M. Kase, H. Kumagai, and J.
Takahashi: RIKEN Accel. Progr. Rep., 17, 65 (1983).
T. Matsuo, J. Urakawa, A. Yagishita, Y. Awaya, T.
Kambara, M. Kase, and H. Kumagai: j. Phys. B, 16,
L239 (1983).
F. P. Larkins: ibid., 4, 1 (1971).
V. S. Nikolaev, L. N. Fateeva, I. S. Dmitriev, and Ya
A. Teplova: Sov. Phys.-jETP, 13, 695 (1961).

86
RIKEN Accel. Progr. Rep. 18 (1984). 111-2-22.

Secondary Electrons Emitted from AI under
Bombardment with He+ and He++
A. Koyama, Y. Sasa, and M. Uda

Total yields, r, of secondary electrons (SE)emitted from metals under bombardment of highenergy light ions are proportional to the stopping
power of projectiles, S, over a wide energy range.
However, in the case of heavy ion impact, r/S decreases with increasing S, even in the high energy
region where projectiles lose their energy mainly
through binary collisions with target electrons (direct
Coulomb interactions) and through collective electron excitations; the energy loss by electron capture
can be neglected. Then the number of SE createdin the surface region should be proportional to S,
as in the case of light ion impact. Nevertheless r/S
decreases with S. Therefore the emission probabilityof SE from the surface might be depressed in thecase of heavy ion bombardment. 1)
In order to elucidate this depression effect on theemission probability, it is indispensable to compareenergy spectra of SE induced by heavy-ion impact
with those induced by light-ion impact. In thisreport energy spectra of SE from Al induced by
He+ and He++ bombardment are compared to study
their projectile charge dependence.
Aluminum was in situ vacuum deposited on asubstrate of stainless steel at 10-9 Torr. The target
was transferred to the target chamber at 2-3 X 10-10
Torr. The angle of an incident beam to the normalof the target surface is 53°. During bombardment,
the pressure of the chamber was kept as low as 5 X
10-10 Torr or less. Surface contamination could not
be found with Auger analysis using 3 ke V electronprobe. The optical axis of the electron energy analyzer was set perpendicular to the target surface.
Thus only those SE emitted in the normal direction
from the surface of the target entered the analyzer
and detected. Their emission angle was 127° relative
to the incident beam direction. A potential of -9 V
was applied to the target, and then SE were accelerated to the analyzer inlet.
Figure 1 (a) shows the energy spectrum of SE
induced by He+ bombardment. Figure 1 (b) is for
He++ bombardment. Incident energies were 1.1
MeV /amu in both cases. The energy spectrum of
SE for incident electrons of 500 eV is also shown forcomparison in Fig. 1 (a). Peaks are those of SE (1 eV)
and Al L-VV Auger electrons (65 eV), and hypersatellites (HS) due to two L-shell vacancies (82 eV).
Both spectra induced by He+ and He++ are almost

---'c
+-'

::J

10000

;::-10 000 .

~

:0
~

..

VI
C

1000

~ 1000

He+ ImpactuHe++ Impact

Q)

-01
>.

ro

-0

.. ·;~···:····'..·:.....,.: ...,..'.:....:.........:.......; ..;r....

c

·0

u
Q)

100

100

VI

.... ............. :-..................: ..: ......":..............:...~.

Electron impact
10~----~------~----~10~----~------~----~-

o

50

100

150

a

50

100

150

Energy of secondary electrons (eV)
(a)

(b)

Fig. 1. Energy spectra of secondary electrons from Al induced by He+ and He++ ion
bombardment. Incident energy is 1.1 MeVjamu for both projectiles. (a) for He+. An
energy spectrum of secondary electrons for incident electrons of 500 eV is also shownfor comparison. (b) for He++.

A. Koyama, et al.

87

Table 1. Intensities of Al L-VV Auger (A) and its hypersatellite peaks (HS) relative to the peak of secondary electrons (SE) and the background (B) at 90 eV.

1.5

A

A-B

SE

SE

HS-B

A- B

HS-B

Projectile
1.00 X 10- 2 6.1 X 10- 3
0.97 X 10- 2 6.5 X 10- 3

He+
He++

~

~ 0.5

SE

B

B

6 X 10- 4
7 X 10- 4

1.5
2.0

0.15
0.23

----------------- - - c2/zi
o

50

100

150

Energy of secondary electrons (eV )Fig. 2. Ratio of intensities of secondary electrons from A1for incident He+ to those for incident He++ of equal energyof 1.1 MeVjamu. The solid curve is to guide the eye. C2 jZ12
is a ratio of square of charge of He+ to that of He++.

the same in shape, except in the high -energy region
above 70 eV. In order to examine this trend more
precisely, R(E)=Nl(E)/N2(E) is shown in Fig. 2.
where Nl(E) and N2(E) are intensities of SE induced
by He+ and He++ bombardment, respectively. R(E)is almost constant and equal to unity in the lower
energy region from 1-70 eV, and then increases
with increasing energy. The increase in intensityof the high energy SE induced by He+ bombardment
is due to backscattering of electrons which arebound initially to He+ ions but ionized through theelectron loss process in the target. In fact, the energy
dependence of the spectrum for He+ impact issimilar, in the high energy region above 90 eV, tothat for electron impact, as shown in Fig. 1 (a).
Since low energy electrons are excited primarily
through distant collisions, their excitation probability should be proportional to the square of

charge of ions. If it is the case, R(E) should beequal to 0.25 (= 12/22) at energies below several eV;
however such reduction in R(E) could not be found.
I t may be caused by the fact that transport processes
diminish the character of the primary excitation, or
the mean free path of the electron loss for He+ isshort enough compared with the escaping depth of
SE. Analysis of this result is now in progress.
In Table 1 heights of SE (1 eV), Al L-VV Auger(65 eV), and its hypersatellite (82 eV) peaks arecompared for He+ and He++ impact. The mark Bmeans the background for the Auger and hypersatellite peaks. The intensity of SE at 90 eV was adopted
as B, because the hypersatellite peaks have no contribution to the background at the energy. Heights
of Auger and hypersatellite peaks relative to thoseof SE (1 eV) are almost the same for both projectiles.
Their heights relative to the background are larger
by 30-50%> for He++ than for He+. This is due tothe smaller value of the background for He++
bombardment.
Reference
1)

A. Koyama, T. Shikata, H. Sakairi, and E. Yagi: ]pn.].
Appl. Phys., 20, 1216 (1982).

88

RIKEN Accel. Progr. Rep. 18 (1984)

111-2-23.

Chemical Bond Effects on Auger Electrons Induced by
He 2 + Ion Bombardment
M. Uda, A. Koyama, and Y. Sasa

Significant chemical bond effects have been reflected in X-ray satellite structures induced by ion
bombardment. 1)-8) Then it is expected to see similar
chemical effects also in Auger spectra. However,no Auger spectra in view of chemical effects, which
are excited with fast ions, have been reported yet.
By the use of an electron spectrometer operated inan ultra high vacuum (,-....,2 X 10- 10 Torr)9) F KLL
or KVV Auger spectra (V: valence band) which were
induced by He 2+ ions accelerated by RILAC wererecorded for a series of fluorides.
In situ vacuum deposition of N aF, AIF 3, andTeflon «CF 2)n) was performed under a standard
pressure of 1 X 10-9 Torr. Thickness of the targets
thus prepared on stainless steel (SUS 310) backing
was about soA. The surface of the targets was preexamined by Auger electron analysis where 2 ke Velectrons were used as an excitation source to confirm its cleanness. He 2+ ions with 1.14 MeV jamu
were obtained by stripping He+ ions having thesame velocity through carbon foil.
He 2+-induced Auger electron spectra for NaF,
AIF 3, and Teflon are shown in Fig. 1. For reference
X-ray-induced Auger spectra for these chemicalcompounds 10 ) are also shown in Fig. 2, where A=
2s 22p 4(lD)+2s 22p 4(lS), C= 2s 12p 5(3P), D=2s 12 p5.(lP), and E=2s 02p 6(lS), expressed in terms of final
state. Here the initial states for these transitions are
the same, i.e. singly ionized states, 1s 12s 22p6(2S).
The peak B is originated from a doubly ionized initialstate 10) where the initial state has one vacancy eachin K and valence band or L 2 ,3 shells. Then the peakB is due to or ascribed to the transition Is 12s 22p5
(3P, IP)-+ls 22s 22p 3(4S, 2D, 2P) or KL 2 ,3(3P,lP)-+
L~,3(4S, 2D, 2P). As can be seen from Fig. 1, thepeak B for N aF induced by He 2+ ion bombardment
is much more enhanced than that induced by X-ray.
This means that a probability to produce double
vacancies on F atoms is much higher in He 2+ ion
excitation than in X-ray excitation. Then a relaxation
process on the F L vacancy prior to F KLL or KVVAuger emission can clearly be seen in the intensity
distribution of the Auger spectra induced by He 2+
ion bombardment. The intensity of the peak B
decreased with the increase in the covalency offluorides in order of NaF, AIF 3, and Teflon. Sucha tendency is more stressed in the ion induced Auger
spectra than in those excited with X-rays. In addition, a shift of the peak D to a low energy side
and line broadening can also be seen in the F KVVAuger spectra of these fluorides, which were excitedwith He 2+ ions. This is, at least in part, caused by

He 2 + ( 1.14 MeV / amu),.

. ........
r1...t.I'.-:O::,'!~.

~ Teflon

~

ro

.

u

(f)

>-

ro
c

Q)

c

~:.

.".

u

V)

Teflon>-ro~ . ;-._.J-...",_,/"-.......,......
. __/ ;.r\.\.

.":'." ".~"': ~
'.

~

.!:

........ . .

., .. ...-.:.

2c

>
ro

ro

.,:':,:1

I'!t ••

~
.iii
c

Q)

~

*:.••

,.:-:.~.. ~-.p:•.

I!.t'"'~~.

.~ L-.-__......".-'--__f\.,... __) 1\\

2-- .:,____M_g~F_2~

.!:

.~

Q3

'.

a::

NaF

I I I I I~"'-""'-'

I
E
I

NaF

~

DCBA
I

J

•
I

I

580

L

680
Kinetic energy (eV )Fig. 1. Auger electron spectra of F KVV or KLL for NaF,
AIF3 and Teflon induced by He 2 + ions with 1.14 MeVJamu.

600

620

640

660

680

Kinetic energy (eV)Fig. 2. Auger electron spectra of F KVV or KLL of several
fluorides induced by Al Ka X-ray.1°)

M. U da, et al.

the overlap of several weak peaks originated fromdoubly ionized initial states. In addition, an intense
background at the low energy side of F KVV for
the ion induced Auger spectra comes from a shoulder
of a broad binary peak centered at about 610 eV.
Further analysis is in progress.
References
1)
2)

3)

P. G. Burkhalter, A. R. Knudson, D. J. Nagel, and K. L.
Dunning: Phys. Rev. A, 6, 2093 (1972).
M. Uda, H. Endo, K. Maeda, Y. Awaya, M. Kobayashi,
Y. Sasa, H. Kumagai, and T. Tonuma: Phys. Rev. Lett.,
42, 1257 (1979).
H. Endo, M. Uda, and K. Maeda: Phys. Rev. A, 22, 1436
(1980).

4)
5)

6)
7)
8)
9)

10)

89
M. U da, H. Endo, K. Maeda, Y. Sasa, and M. Kobayashi : Z. Phys. A, 300, 1 (1981) .
M. Uda, K. Maeda, H. Endo, Y. Sasa, and M. Kobayashi: Inner-Shell and X-Ray Physics of Atoms andSolids, (eds D. J. Fabian, H. Kleinpoppen, and L. M.
Watson), Plenum, New York, p. 205 (1981).
H. Endo and M. Uda: Z. Phys. A, 306,187 (1982).
R. L. Watson, F. E. Jensen, and T . Chiao: Phys. Rev. A,
10, 1230 (1974).
O. Benka, R. L. Watson, and R. A. Kenefick: Phys. Rev.
Lett., 47, 1202 (1981).
A. Koyama, Y. Sasa, Y. Ishibe, A. Shiraishi, T. Shiga,
H. Omori, K. Nishi, M. Fuse and M. Uda: RIKEN
Accel. Progr. Rep., 17, 122 (1983).
M. Ucla, K. Maeda,A. Koyama, and Y. Sasa: Phys. Rev.
A, 29, 1258 (1984).

90
RIKEN Accel. Progr. Rep. 18 (1984)

111-2-24.

Studies of Magnetic Structure of Cobalt Ferrite Surfaces by
119Sb Emission Mossbauer Spectroscopy
T. Okada, F. Ambe, S. Ambe, and H. Sekizawa

A part of the present investigation has been reported. I ) The present report is concerned with theresults of subsequent detailed research. The magnetic properties and the chemical states of dilute
Sn (+-Sb) ions on the surfaces of CoFe204 has
been investigated by means of 119Sb emission
Mossbauer spectroscopy. Since the origin of thehyperfine magnetic fields Hhf a~ the nuclei of
119Sn (+-119Sb) is the electron-spin polarizationinduced by the surrounding magnetic ions throughoxygen ions, the investigation of the fields supplies
important information on the exchange interactions
between magnetic ions near the surfaces.
Experimental procedures have been reported inprevious reports. 1), 2) A tin plate was irradiated with
about IC of 38-MeV a particles accelerated by thecyclotron. The desired nuclide 119Sb remaining insolution was purified by various chemical separa-

CoFe 2 0~ -tions. Carrier-non-added 119Sb (~119Sn) ions wereabsorbed hydrolytically on the surfaces of the ferrimagnetic oxide powders of CoFe204, the Neeltemperature of which was about 520°C. Emission
Mossbauer analysis was made on 119Sn arising from
119Sb on the surfaces of CoFe204 by means of aconventional spectrometer in absorber-drive mode.
Emission Mossbauer spectra of the "as adsorbed"
CoFe204-119Sb at 297 K (A), 77 K (B), 5 K(C), and 5 K with an external magnetic field H ext(D) are shown in Fig. 1. The field H ext of 35 kOe
was applied parallel to the r-rays. It can be seenfrom Fig. I that emission lines at 297 K (A) and
77 K (B) are considerably broadened compared withthat of diamagnetic 119Sn 4+ ions in nonmagnetic
material, and that the lines at 5 K (C) and (D) aresplit into two wide peaks through the supertransferred hyperfine interaction. From the values ofisomer shift (+0.2 mm's- I relative to BaSnOa),
it is certain that the 119Sn ions resulting from 119Sb5 +1l9Sb"as adsorded"
Co Fe 20 4 -1l9Sb

100"as adsorbed"

99•.... '-'--:-;-:":L,•• •..
.b.-

..,

.. '

100

~
c:

o

98

.'

A 297K

"

I

' Vi
<fl

c:

.~ 100

o

c:

~

~

.2

(.)

ro

c:

c:

o

~

98

:J

.D

EVI
6

98
Hext=35 kOe

-10

o

+10

Velocity (mm s- J)

Fig. 1.

Mossbauer spectra of "as adsorbed" CoFe204-119 Sb.

Hyperfine field (kOe)

Fig. 2. Distribution function P (H) of the hyperfine magnetic
fields of "as adsorbed" CoFe204- 119 Sb.

91

T. Okada, et ai .

--;;-....Q)in Bulk::Jro.~onsurf~
100 ~
~
.~

::
ro

2i 40 ::\

'0

Peak III:0r;:

Hh£ in

bulk

~

:::E

~100

Peak

......

1:7 30 ~v - - - -_ _-<l III

o

·Vi
c:

.... 50

2c:

i ::\

Q)

<..>

2So

L-__~__~~=-~

0100"- ~r.-------....c. II
I

o.

o

x

ro

~

.

Q)

2150

VI

200

100

200

300

Temperature (K)

10

300

"'x

Fig. 4.

Center of peak I, II, and III and Hhf in the bulk

Temperature (K)Fig. 3. Integrated intensities of peak I, II, and III and of
Mossbauer spectra of "as adsorbed" and bulk CoFe204119Sb.

ions are tetravalent. Integrated intensities of the
Mossbauer spectra of specimens (A), (B), (C), and(D) in Fig. 1 are in a ratio of 0.6: 0.8: 1.0: 1.0(see Fig. 3). From this ratio, it seems that the 119Sb
ions adsorbed on one or two layers above the surfaces
are bonded with oxygen ions more weakly than the
119Sb ions in the bulk. Mossbauer spectra wereanalyzed by the Hesse-Riibartsch method, and theobtained distribution function P(H) of the hyperfine
magnetic field Hhf is shown in Fig. 2. Figure 2
shows that P(H) at 297 K (A) and 77 K (B) consistof two main parts and a small one and that P(H)of (C) is apparently made up of three parts. These
P(H) are preliminarily analyzed by means offitting with Gaussians, and divided into three peaks(called peak I, II, and III in order of magnitude).

The results of fitting are shown by the dottedlines in Fig. 2. The peak I in (A) and (B) are verysmall but suddenly grow at low temperature in (C)and (D). From Fig. 3 it seems that (1) 119Sb5 + ionsadsorbed to give peak I are very loosely connectedwith oxygen ions in the matrix because integrated
intensity of peak I is very small in (A) and (B), and(2) magnetic property of 119Sb ions giving rise to
peak I is superparamagnetic because the values of
Hhf are almost zero in (A) and (B) and about
30 kOe in (C) and (D), as seen in Fig. 4. These
results indicate that a part of the magnetic IOns
near the surface layers are superparamagnetic.
References
1)
2)

T. Okada, S. Ambe, F. Ambe, and H. Sekizawa: RIKEN
Accel. Progr. Rep., 17, 74 (1983).
T. Okada, F. Ambe, S. Ambe, and H. Sekizawa: Phys.
Chem., 86, 4726 (1982).

92
RIKEN Accel. Progr. Rep. 18 (1984)

111-2-25.

Perturbed Angular Correlation of r-Rays Emitted from
111Cd (f--111In) in a-Fe 2 0 3
K. Asai, F. Ambe, S. Ambe, T. Okada, and H. Sekizawa

Time differential perturbed angular correlation(TDPAC) of r-rays is a valuable tool not only inthe field of nuclear physics but also in the fields ofsolid state physics and chemistry. The nuclide 111Cd(~111 In) is one of the most popular ones used
this type of measurement. It emits 171-245 ke V cascade r-rays through the 5/2+ intermediate state
which has a half life of 85 ns. It has been reported
that hyperfine frequencies at 111Cd are widely distributed in insulators1),2) due to the after-effects ofthe preceding electron capture (EC) decay of 111 In.
Because these distributions were large enough tosmear out the hyperfine interactions inherent in
the host materials, it is widely believed that TDAPC
using a nuclide after EC decay is not useful instudying insulators. 3) , 4)
Salomon,5) in 1964, made TDPAC measurement
on In203 at 280°C and found that the after-effects
were considerably reduced at this temperature.
This finding suggests that a nuclide after EC decay
is also useful in studying insulators by making a hightemperature measurement, but this fact seems toremain unnoticed. It can be also said that the aftereffects themselves should be investigated further
because they provide valuable information on theelectronic excited states of the ions concerned.
We measured TDPAC of r-rays emitted froml11Cd (~111 In) in a typical antiferromagnetic oxidea-Fe203 (TN= 680°C) in a wide temperature range
from 20°C to 714°C to establish the utility of a hightemperature measurement and to study the featuresof the after-effects in magnetic insulators observed
around room temperature. In this report, we present
some of the results obtained in the present study.
The detailed description of the experimental procedures such as sample preparation, data taking andprocessing, and analysis are given in Ref. 6.
Some representative spectra of A 22 ·G22(t) obtained in the experiment are shown in Fig. 1. In
a-Fe203, it is expected that 111In3 + ions replace
Fe 3 + ions, and the daughter l11Cd nuclei feel boththe hyperfine magnetic field H hf , supertransferredfrom Fe 3+ ions, and the electric field gradient (EFG).
If there is no disturbance around 111Cd such as theafter-effects of the EC decay, it is reasonably assumed that (1) both Hhf and EFG are unique, (2)inthe EFG is axially symmetric, and (3) the angle 0
between the direction of H hf and the z-axis of
EFG is 90°.
First, we analyzed the observed spectra based on
the above assumptions. The values of the Larmor
angular frequency WL and the quadrupolar angularfrequency WQ were obtained by a least-squares fittingof the data with a semi-empirical formula A 22 ·G22(t)= C 1 x G22 (t)uniq+C2 in the region t~50 ns. In
this formula, G22 ( t)uniq is the theoretically given
perturbation factor as a function of WL and WQ,
on the assumption that a random orientation of
microcrystals with a unique static interaction,7)
and C 1 and C 2 are adjustable parameters. The
spectra measured at high temperatures were reproduced considerably well with negligibly smallvalues of C2 (Fig. 1 (a) and (b». On the other
hand, those measured at low temperatures were
only poorly reproduced (Fig. 1 (c». These resultsmean that the above assumptions hold well at hightemperatures, whereas they do not at low temperatures.
Next, we analyzed the spectra measured at low
temperatures assuming a distribution of one of thehyperfine parameters. We define a quantity G22(t)L1~
as the perturbation factor when a hyperfine

0'1~
WT=656.CA A ~t ~ i' ~hl~:~~•

0.00 .
- 0.05-:;:;-

0.15 ,

I

0.00- 0.05~ ~~~ -,

tA

A

f ll

to

V'V~~rW(b) T = 420·C

1

I

v.~
f
.

0.15

T = 20°C

-0.05

o

50

100

150

200

250 300

Time ( ns )Fig. 1. TDPAC coefficient A22' G22(t) of the l11Cd( +-- 111 In)
r-r correlation in a-Fe20 3. (a): at 656°C, (b): at 420°C, and(c): at 20°C. The solid curves represent the fitted values of
C1 X G2 2(t)uniq +C2.

93

K. Asai, et ai.

0.15

T = 20 e-

012[).w=8"1o--;n 10----- [).9 = 6°

0.1

''0
-

~

8

~

I

0
....

x-4

-005

I

I

:a

I

OL---~50~--~IO0----~
15~
0----~200----~250----~300

Time (ns)2(a)

8~ 2.4~ ~ 0.1:a '-' 0(b)100200 300 400 500 600 700 800
Temperature (oe)Fig. 4. Temperature dependences of hyperfine frequencies
for I11Cd in a-Fe203. (a): WL, (b): wQ.

100,,-100e

4

0 r-----------------~~
2.6~ _'I ___ 2.5 -----0-0-...0..

Fig. 2. TDPAC coefficient A22' G 22 (t) of the 111Cd(+- 111 In)
r-r correlation in a-Fe203 at 20°C. The solid curve represents the fitted values assuming a distribution of JWQ/wQo =8 %, and the dotted line represents the values assuming JO =6°.

Fig. 3.

6°--0 - 0

200 300 400
Temperature (OC)

Temperature dependence of JWQ.

parameterin the interaction Hamiltonian has aGaussian distribution around ';0 with a width LI';.
We examined the three cases of .; = WL, WQ, or (J byapplying a least-squares fitting. In the case of .; =WL, the X2-factor was not reduced by assigning any
finite value to LlWL' On the contrary, the factor was
reduced considerably on assuming 1) a distributionof WQ with LlwQ/wQo= 8 % or 2) that of (J with LI(J=6°
around (J0 = 90°. The fitted curves for the spectrum
at 20°C are shown in Fig. 2. The obtained valuesof WL were the same for these two cases, and thatof WQO for the case 1) was equal to that of WQ for thecase 2).
The temperature dependence of LlwQ giving thebest fit is shown in Fig. 3. The value increases
rapidly with the decrease in temperature below
200°C. The temperature dependences of Hhf and(f)Q (or wQo) are shown in Fig. 4 (a) and (b). Thesetemperature dependences of Hhf and WQ (or wQo)
are those expected for the electronic ground state
111Cd ions.
The distribution of the hyperfine parameters observed at low temperatures is ascribed to the aftereffects of the preceding EC decay. The plausible
mechanism is as follows. The 111Cd ions arisingfrom 111 In are in highly excited electronic states as
the result of the following Auger effect, and thenrelax to the stable state through some low-lying
electronic excited states which have rather long

lifetimes; IllCd nuclei in the ions which are stillleft in these low-lying excited electronic states also
contribute to the perturbation factor along with
111Cd in the ions already relaxed to the stable state.
Probably, each 111Cd nucleus in the excited ion
feels some extra EFG in addition to the EFG in thestable-state ion because of some electronic defectin its environment. The temperature dependence ofthe distribution means that the lifetime of the excitedions decreases with the increase in temperature,
because of an increase in electron mobility resulting
in a high rate of valence rearrangement.
It is revealed by the present work that the aftereffects of the preceding EC decay of 111 In do not
influence the TDPAC spectrum of 111Cd in aFe203 at high temperatures, where the excited ionsare annealed out in a short enough time. Thisfinding proves TDP AC of IllCd (~lll In) to bea valuable tool for the study of insulators at hightemperatures. The features of the excited 111Cd
ions and of their relaxation mechanism are now
under consideration. We have a plan to use a nuclide
11lCd (~lllmCd) for the study of insulators at ·low temperatures, because it is known that the aftereffects of isomeric decay on TDPAC spectrum are
negligibly small. 2)
References
1)
2)
3)
4)
5)
6)
7)

P. Lehmann and J. Miller: ]. Phys. Radium, 17, 526(1956).
H. Haas and D.A. Shirley: l. Chem. Phys., 58, 3339
(1973).
J. P. Adloff: Radiochim. Acta, 25, 57 (1978).
P. Boyer and A. Baudry: Hot Atom Chemistry, (ed. by
T . Matsuura), Kodansha, Tokyo, p. 315 (1984).
M. Salomon: Nucl. Phy s., 54, 171 (1964).
K. Asai, F. Ambe, S. Ambe, and H. Sekizawa:]' Phys.
Soc. lpn., 53, 4109 (1984).
H. Frauenfelder and R. M. Steffen: a-, f3- and r-Ray
Spectroscopy, Vol. 2, (ed. by K. Siegbahn), NorthHolland, Amsterdam, p . 1111 (1964).

94
RIKEN Accel. Progr. Rep. 18 (1984)

111-2-26.

TDPAC of r-Rays Emitted from 111Cd (~111In) In Fe 3 0 4
K. Asai, T. Okada, and H. Sekizawa

Nuclei of diamagnetic ions in magnetic oxides
feel the hyperfine magnetic fields transferred fromthe neighboring magnetic ions through the intervening oxygen ions. This quantity, the supertransferred hyperfine magnetic field H STHF , has been
widely studied because it provides information on
the superexchange interactions between the magnetic ions in the oxides. 1) Time differential perturbed angular correlation (TDPAC) of r-rays
emitted from 111Cd (+-111 In) is a useful method inthis type of studies. In the present report, we present
some remarks on the experimental geometry inmeasuring HSTHF in a ferro- or a ferrimagnet,
and then show some results in Fea04 obtained with
the newly proposed geometry.
When the specimen is a collinear ferro- or a
ferrimagnet polycrystal, coincident counts N.L «(), t)of the cascade r-rays are measured usually with an
external magnetic field H ext applied perpendicular to the detectors plane in order to polarize
the magnetization of the specimen to this direction,
where (} is the angle between the cascade r-rays,
and t, the time interval between them. We define
the direction of H ext as the z-axis of the system.
The direction of H STHF is expected to be parallelor antiparallel to the z-axis in this setup.
One method employed widely for deriving thefrequency profile of the Larmor frequency WL is
to derive it from the frequency spectrum of thenormalized difference R(t) between the coincident
counts at (}=7rjZ and 7r. The definition of R(t) IS
as follows:

We call, hereafter, this method "multiple 7r/Zmethod". This method, however, has some drawbacks in actual experiments:(1) The sign of WL cannot be determined.
(Z) The time spectrum R(t) has the Fourier components not only at W=2WL, but also at WL andat 0, if the magnetizations of the microcrystals
are not completely aligned to the z-axis. In
this situation, the profile of ZWL is not obtained
directly from the Fourier spectrum of R(t).
(3) The time spectrum R(t) has non-zero value andcan oscillate, even when there are no appreci-

able hyperfine magnetic interactions at thenuclei. Thus, a false value of WL can be derived
in this case.
Then, we propose another method to derive thefrequency profile of Wv In this method, the profile
is derived from the Fourier spectrum of the normalized difference R' (t) between the coincident
counts at (}=3/47r, and +3j47r. The definition ofR'(t) is as follows:

R'(t)=[N.L(-3/47r, t)-N.L(+3/47r, t)]/[N.L (-3/47r, t)+N.L (+3j47r, t)]'. !

A 22sin (2WLt)

We call this method "multiple 7r j4-method". Thismethod has no drawbacks described above:(1) The profile of WL is determined up to the sign.
(Z) The spectrum R'(t) has no Fourier components
except at W=2WL, even if the magnetizations
are not completely aligned to the z-axis provided that they are symmetrically distributed
around it. In this situation, the amplitude of
the frequency component at W=2WL is reduced.
(3) The spectrum R'(t) is always equal to zero,
when there are no appreciable hyperfine magnetic interactions at the nuclei.
Thus, we consider that the "multiple 7r /4-method"
is more appropriate than the "multiple it' j2-method"in the study of H STHF of a ferro- or a ferrimagnet
below the Curie temperature.
Figure 1 shows the spectra of R'(t) in Fea04 at
various temperatures. The value of WL (=-rHsTHF)
is positive, meaning that the direction of HSTHF isparallel to that of H ext because the nuclear gyromagnetic ratio r of the 5/2+ state of l11Cd is negative.
The profiles of WL derived from R'(t) are shown in
Fig. 2. The distribution of WL is narrow at temperatures above 131 K, whereas considerably broad attemperatures below 110 K. On the assumption that
HSTHF (ocwd has a Gaussian distribution, the center
value and the width of the distribution are calculated
by a least-squares fitting. 2) The results are shownin Fig. 3. There are stepwise changes both in Hoand JH.
The detailed mechanism of the distribution of
HSTHF will be presented elsewhere. Only the qualitative explanation is described in the following. In
Fea04, 11ICd nuclei are in the tetrahedral (A) sites

K. Asai, et ai.

95.

Fig. 2.

Profiles of the Larmor frequency (f)L.

o 6. "multiple 11"/ 4 melhod"• ... "multiple 11"/ 2 method"

-0.1

150

oL----L--~10-0---1~50----20~0---2~5-0--3~00

50

15Time (ns)Fig. 1. Normalized anisotropy R'(t) of the coincident counts
in Fe304.

o.x

<3
.x

~

and feel HSTHF transferred dominantly from theoctahedral (B) site magnetic ions. There are nominally the same number of Fe 2+ and Fe 3 + ions in theB sites in this oxide. At high temperatures about thethe Verwey temperature (Tv =120 K), 3d electrons of the ions itinerate among them and thus, there
are only one kind of Fe ions in the B sites and HSTHF
felt in the A site is unique. On the other hand, at
low temperatures below Tv, Fe 2+ and Fe 3+ ions
are ionic ally ordered in the B sites 3) in a way that
there are some kind of non-equivalent A sites andthus HSTHF felt in the A site is distributed.
In the present report, it is shown that TDPAC of
r-ray is a useful technique in the study of HSTHF
in the magnetic oxide. The study on various magnetic oxides other than Fe304 is in progress.

100l---- 100

50

O

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

100

200

300

Temperature ( K)

Fig. 3. Temperature dependences of the center value Hoand the width JH of the distribution of H STHF. 0 and 1':,
represent the values obtained by the "multiple 7rJ4-method",and. and .6., by the "multiple 1rJ2-method".

References
1) B. J. Evans and L. J. Swartzendruber: Phys. Rev. B, 6,2)3)

223 (1972).
H. Sekizawa, K. Asai, T. Okada, N. Sakai, N. Shiotani,and E. Yagi: IPCR Cyclotron Progr. Rep., 11,106 (1977).
G. Shirane, S. Chikazumi, J. Akimitsu, K. Chiba, M.
Matsui, and Y. Fujii: j. Phys. Soc. jpn., 39, 949 (1975).

96
RIKEN Accel. Progr. Rep. 18 (1984)

111-2-27.

Perturbed Angular Distributions of Gamma-Rays from
Dy under Transient Magnetic Field
A. Hashizume, N. Sakai, and K. Asai

When a recoil nucleus produced by the Coulomb
excitation process is implanted into a polarized
ferromagnetic material, the nucleus receives astrong magnetic field in the deceleration process.
The hyperfine interaction between the transientmagnetic field and the magnetic moment of thevery short-lived excited nuclear level causes precession of angular distribution of the r-rays emitted
from the state.
As reported in Ref. 1, perturbed angular distribution experiments of r-rays were performed bybombarding natural dysprosium evaporated ontoa 6 pm Fe foil by 48 to 51 MeV 40Ar ions accelerated
by RILAC. In r-ray spectra, 168.8 keV (4+--+2+)
r-ray in 164Dy was well separated. A 2 =0.137 ±0.012, A 4 =-0.07±0.012, and A 2 = 0.122±0.014,
A4= -O.011±0.02 were obtained for the angular
distribution of the r-rays when the external fields
of upward and downward direction were applied
perpendicular to the plane defined by the incident
beam and r-ray detection directions. An angular
shift of 0.39 rad was observed.
Parametrizations of the transient magnetic field
have been proposed by many authors. We used thefollowing equation to estimate the transient magnetic
field. 2)

B(v, Z) = a·Z(v/vo)·exp( - /1vo/v),
where B is the transient field, Vo the Bohr velocity,
and a and f3 are parameters. The value of g factorof the 0.242 keV (4+) state is not known. Howeverfrom the systematics, it is expected that the value
is not so different from that of the 2+ state. If an
equation, g(I)=g(2)(1+aI2)/(1+4a), is used witha parameter a = - 1. 5 X 10- 3 obtained from 160Dy,
and with g(2)=+0.684 for 164Dy, an approximately
calculated value becomes 0.42.
By using the parameter a= 11.5 T and /1 = 0.1, themean precession angle was calculated from~ (t) = -0.047g): B(t) dt (mrad·T-l.ps- l)

and<P= A~~ ~(t)'exp( -),t)dt,
where ~(t) is the precession angle, cfi the mean precession angle, and A the decay constant of the excitedstate. U sing the maximum recoil velocity of Dy
caused by 40Ar ions, one obtains 0.62 rad as an
upper limit of the precession angle. The obtained
experimental value is to within this limit. We are
now developing a code following the method ofWinther and de Boer to make more precise analysis.
References
1)
2)

A. Hashizume, N. Sakai, and K. Asai: RIKEN Accel.
Progr. Rep., 17, 27 (1983).
O. Hausser, H. R. Andrews, D. Ward, N. Rud, P. Taras,
R. Nicole, J. Keinonen, P. Skensved, and C. V. Stager:
Nucl. Phys. A, 406, 339 (1983).

97

RIKEN Accel. Progr. Rep. 18 (1984)

111-2-28.

Plasma Wall Interaction

Y. Sakamoto, Y. Ishibe, S. Ishii, A. Minoh, K. Okazaki,
H. Oyama, K. Yano, and S. Kakinuma

We report the present status of three studies relating to plasma wall interaction: (1) deuterium atom
depth profile near a surface of TiC irradiated with
an ECR plasma, (2) LIFS (laser, induced fluorescence spectroscopy) measurement of physical sputtering of iron bombarded by plasma ions and (3)interaction of hydrogen ions with iron oxide.
(1) Deuterium atom depth profile near a surfaceof TiC irradiated with an ECR plasma
It is indispensable to know the depth profiles ofhydrogen isotopes near the surface in order tounderstand their recycling in fusion devices ormechanism of discharge cleaning. We have been
investigating TiC samples irradiated by an ECR
deuterium plasma. TiC is one of the most importantfirst wall materials of fusion devices in the near
future. The ECR hydrogen (isotope) plasma produces abundant neutral atoms useful for dischargecleaning. The TiC samples (20 pm in thickness) wereprepared by means of CVD coating on poco graphite
substrate. The samples contain much hydrogen
owing to its manufacturing process (CVD). This is areason why we use a deuterium plasma.
Figure 1 shows the deuterium plasma irradiation
apparatus. The electron density and the temperature of plasma were respectively 9.6 X 109 cm-3 and4.7 eV at a gas pressure of 2 x 10-2 Pa. The flux
densities of ion and neutral atom flowing onto thesample surface becomes about 1015/cm 2'sec respectively.
Deuterium atoms near the surface were detectedby ERD1) (elastic recoil detection) method by using
Ar 4+ beam from the RILAC, whose incidence angle

and energy were 30° and 46.92 MeV, respectively.
Figure 2 shows the depth profiles of Hand D. The
arrows indicate the energy of recoiled atoms
from the surface. The deuterium density near thesurface increases with irradiation time. The hydrogen density decreases with irradiation time;
this is because of desorption of hydrogen due tothe sample temperature rise during the irradiation(200°C). Deuterium atoms are distributed up to
several thousand A from the surface, but reachsaturation near the surface after 5 hr irradiation.
Since during the ECR discharge cleaning the wall
temperature is kept at about 200ac, we must assume
a similar density profile.
(2) LIFS measurement of physical sputteringof iron bombarded by plasma ions
Since the LIFS method gives a useful information
for the assessment of materials under the irradiationby plasma particles, we measured physically sputtered Fe atom flux near the target by this method.
A preliminary experiment has been carried out toobtain the relative neutral Fe atom density.2)
Figure 3 shows the experimental arrangement.
An ECR plasma was produced in a magnetic mirror
field by applying 9 GHz, 2 kW, pulsively modulated(10 ms) microwave. The target was set at the endof a plasma column and insulated from the wall inorder to give arbitrary bias voltage. Gases usedwere Ne (M=20), Ar (40), and Kr (84). Light froma laser (Phase R. Co., dye laser, DL-2100C) wastransformed into the second harmonic by an ADP
crystal. Output power was 6.2 kW (at 3,020 A) anda saturation parameter was 0.4. By exciting Fe

ijj 0·39zz«!JtJC,~~.,\

in
t-

\ \
:,'t"
: \

Go.Z6

......ANTENNA--- as received..... DZ plasma i rrad. 5hr.

H

Z

50.13

20hr.

;

\

\

'I

u

\ \,1
MOVABLE LANGMUIR
PROBE

a1,,1, GHz MICROWAVE

Fig. 1. Schematic arrangement of D2 plasma irradiation
apparatus.

"'P~~
,
d8

"64 .

CHANNEL NUMBER

Fig. 2. Deuterium atom depth profiles in the near surfaceof TiC irradiated with ECR plasma, together with that ofhydrogen. Arrows show positions of surface atoms.

98

Y. Sakamoto, et al.

B( kG)

5

~

I

30cm

DAE[JSSI
--, ,
I
I

:

SAMPLE PIECE

MONOCHROMATOR
DYE LASER

Fig. 3.

Apparatus for plasma irradiation of Fe metal sample and the measurement system.

10 3

Ar

103

Nt>

5

10
t::.

5

t::.

·c

5

0

./

./
/"

./

.;'

./

.ri
(;

J'

Kr

./

:J

~

3

./

.;'

./

~

10 2

c

5

9_0..-

t::..//

210.......... 0

10

2

/

0

/

/

..- ...-

./

/

5

0

5

/
I::..

10' L--.....L.-_""'--::-----L_ _...1--J
5
103
2
5 8
bias [V]

10

5

10

bias [V]bias [V J

Fig. 4. Variation of iron density with bias voltage. Dotted lines present relative sputtering yields.

atoms by the transition a5D4-+y5D4° (3,020 A) or
a5D4-+y5D4° (3,059 A), we observed fluorescencey5D 4o-+a5F 5 (3,820 A) using a condenser system(F/lO) and a monochromator (25 em). Figure 4
shows the dependence of the measured atom
density on the bias voltage; a dotted line represents
the dependence of the relative sputtering yield on
the ion energy (calculated by Yamamura's formulaand adjusted for the best fit).3) A good agreement
between the yield and the measured value was obtained with N e, but deviation found was large withlarge ion masses (Ar and Kr).
In the next experiment we will determine theabsolute value of density as well as the velocity
distribution in order to determine atom flux.

Study on reduction of metal oxide by hydrogen ion
In the glow discharge cleaning process, ions haveenergies of several hundred eV. This experiment
aims at the elucidation of a reduction mechanism ofmetal oxide by incident ions, H+ and H2+. An
effort has been devoted to realize clean conditionsin the Auger electron analysis chamber: lO-6 Pa
and low H 2 0 partial pressure.
(3)

References
1)

2)

3)

Y. Yatsurugi, O. Kuboi, M. Hashimoto, H. Nagai, M.
Aratani, 1. Kohno, and T. Nozaki: Appl. Phys. Lett.,
44 (2), 246 (1984).
K. Okazaki, A. Minoh, S. Ishii, Y. Ishibe, H. Oyama, Y.
Sakamoto, and K. Yano: 25th Vacuum Symp., 31Ba-5,
Oct. 29-31, Osaka (1984).
N. Matsunami: IPPJ-AM-32, Nagoya Univ. (1983).

99
RIKEN Aeeel. Progr. Rep. 18 (1984)

111-2-29.

Origin of Hydrogen in Amorphous Silicon Produced by
Glow-Discharge in Si 2 H6 +D 2 and Si 2 D6 +H 2
O. Kuboi, M. Hashimoto,· Y. Yatsurugi, H. Nagai, M. Aratani,
M. Yanokura, S. Hayashi, 1. Kohno, and T. Nozaki

Recently, more and more investigators have been
studying hydrogenated amorphous silicon (a-Si: H)
growth from disilane because of the faster growthwith disilane than monosilane. We have previously
reported amorphous silicon growth from monosilane. I ) It appears that the growth mechanism withdisilane is different from that with monosilane. 2)-7)
We employed the identical test set-up for thesetests as those reported previously with monosilane.
1 Hand D in amorphous silicon were measured by
Rutherford recoil measurement technique.!) Amorphous silicon was deposited by means of RF glow
discharge on a high-purity silicon wafer at 250°C
and at 1 Torr. The two gas mixtures used in thisinvestigation were Si2H 6 +D2 and Si2D 6 +H2. The
following chemical reactions show methods employed to synthesize Si2H 6 and Si2D 6 •Si+3 SiCl 4 ~ 2 ShCl 6(1)

2 Si 2C1 6 +3 LiAIH4 ~2 Si2H 6 +3 LiCI+3 AICta(2)

2 Si2C1 6 + 3 LiAID 4 ~2 Si2D 6 +3 LiCI+3 AICta(3)

Si2H 6 and Si2D 6 so produced were purified by
distilling three times.
Figure 1 shows the relationship between amorphous silicon growth rate and the RF power. It
shows that the growth at A and B is almost the sameagainst the RF power. But, at low power, the growthat B is much larger than at A. It was said in generalthat the amorphous silicon growth rate with disilane
is 5 to 20 times faster than with monosilane. 8)
However, our tests show that this tendency is apparent only at low power. Let us examine curves B
and C. The flow rate of disilane in C is twice thatof B. At low power, the growth rate of C is also
twice that of B. However, at high power, the difference in the growth rates becomes smaller.
Figure 2 indicates the relationship between 1H
and D in amorphous silicon vs. RF power when thegas mixture is Si2H 6 +D 2. At low power, an excessive amount of 1 H from Si2H 6 appears in theamorphous silicon. On the other hand, at highpower, an excessive amount of D from the dilution
gas D2 appears in the amorphous silicon.
Figure 3 shows the isotopic fraction of 1 H in amor-

4.0..-------------,

30.------------,

3.0

~

u

~

~

"-

o~

0

Q)

<0

-:0

a:

.~

.J::

~

c

i0

~

c

~

c

10

0

U

0
II:

0

:I:

10

20

30

40

50

70

80

RF Power (watts)

Fig. 1. Growth rate vs. RF power. Gas flow rate: ,6.; (A)SiH4(10 seem)+D2(40 seem), 0; (B) ShH6(S seem)+D2(40 seem), . ; (C) Si2H6(10 secm)+D2(40 seem).
• Komatsu Electronic Metals Co.

00

10

20

30

40

50

60

70

80

RF Power (watts)

Fig. 2. H, D, and H+D concentrations in a-Si:H:D vs. RF
power. • ; H+D, ,6.; H, ... ; D. Gas flow rate, Si2 H 6(10seem) +D2(40 seem).

100

O. Kuboi, et aZ.

(H)

(sec)

1.0

100
90

0.9

Total Volume of Si 2 Hs···1 00 sec(Si2Hs: I 0 seeM, D2 : 40 seeM)

III

«I
(!)

O.B

ii5

0.7

.S
I

70

.£

60

Q)

0.6

c

~

'0
c

U)

0.5

"0

c

0
' ;:;

u

~
I.i..

u
'0.

to.

~

50
40

Q)

0.4 .

c

~

30

.iii

i5

0.3

'+-

Q

0

0··· Disi lane

2III

to
~

III

80

20

0

Q)

0.2

E

::J

~

0.1

10

20

RF
0

0

10

(0)

20

30

40

50

60

70

BO

RF Power (watts)

Fig. 3. Isotopic fraction of H in a-S:H:D vs. RF power. Gas
flow rate: 6 , A., V ; Si2H 6(10 sccm) + D2(40 seem), T;
Si2D6(10 sccm)+H 2(40 seem).

30

Fig. 4.

50

60

70

80

Fig. 5. Volume of silanes in waste gas of glow discharge.
Gas flow rate, Si2H 6(10 seem) + D2(40 seem). Sampling
period: 10 min. 0 ; Disilane, 6 ; Silane.

wafer through the following reaction.
Si2H 6 -+ SiH2+ SiH 4

Waste Gas Trap

40

Power (watts)(4)

At high RF power, however, monosilane started todisappear. It could be that silanes, polymer, H2 andetc. were formed and higher silanes, polymer, andetc. were deposited on the pipe wall preventing
the compound reaching the trap. Judging from thedata in Fig. 3, SiH 2 intermediate seems to decompose into silicon and hydrogen. Further tests
need to be conducted to confirm the presence of
these heavier compounds.

Trapping system for silanes.

References
phous silicon vs. RF power. It clearly shows thatregardless of whether Si2Ho or Si2D 6 is used, an
excessive amount of the gas atoms in disilane (1 H :in case of Si 2H 6 , D: in case of Si 2D 6 ) appears in
the amorphous silicon at low RF power, while anexcessive amount of the gas atoms in the dilution
gas appears in the amorphous silicon at high RF
power. In contrast with the above data, our previous
tests with monosilane showed that, at high power,
1H in amophous silicon approached the isotopic
equilibrium of the gas mixture. 1)
As shown in Fig. 4, tests were also conducted totrap condensible gases in the exhaust gas stream todetect the presence of SinH 2n+2. The test results
are shown in Fig. 5. At low RF power, a substantial
amount of monosilane was captured; this suggests
SiH2 could have been decomposed on the silicon

1)

2)
3)

4)
5)
6)
7)

8)

Y. Yatsurugi, O. Kuboi, M. Hashimoto, H. Nagai, M.
Aratani, M . Yanokura, 1. Kohno, and T. Nozaki: Appl.
Phy s. L ett., 44, 246 (1984).
B. A. Scott, R. M. Plecenik, and E. E. Simonyi: ibid., 39,
73 (1981).
Y. Mishima, M. H irose, Y. Osaka, K. Nagamine, Y.
Ashida, N. Kitagawa, and K. Isogaya:Jpn.}. Appl. Phys.,
22, L46 (1983).
A. Matsuda, T. Koga, H. Tanaka, L. Malhotra, and K.
Tanaka: ibid., p. Ll15.
B. A. Scott, J. A. Reimer, and P. A. Longeway: j. Appl.
Phys., 54, 6853 (1983).
P. A. Longeway, R. D. Estes, and H. A. Weakliem: j.
Phys. Chem., 88, 73 (1984).
A. Matsuda, T. Koga, H. Tanaka, and K. Tanaka: 10th
Int. Conf. on Amorphous and Liquid Semiconductors,
Tokyo (1983).
B. A. Scott, M. H. Brodsky, D. C . Green, P. B. Kirby,
R. M. Plecenik, and E. E. Simonyi: Appl. Phys. L ett.,
37, 725 (1980).

101

RIKEN Accel. Progr. Rep. 18 (1984)

111-2-30.

Application of Heavy-Ion RBS to the Analysis of
Silicon Ohmic Contact Systems
K. Ikeda, N. Ito, T. Aimi, S. Hayashi, M. Yanokura,
1. Kohno, H. Nagai, M. Aratani, and T. Nozaki(l) Introduction
Heavy-ion Rutherford back-scattering (RBS) wasused for the depth profiling of gold and antimony insemiconductor silicon. In order to take electricalcontact with the bottom side of a silicon powerdevice, some metals are evaporated on the bottom
surface and then caused to make alloy by heat treatment. The bottom surface has often been roughenedby sand-blasting. As the metals, gold containing asmall quantity of antimony is frequently preferred.
(2) Experimental
Description of the samples used in the present
study is given in Table 1 along with the results ofneutron activation analysis of Au and Sb. The
samples were prepared by the following processes,with due considerations towards application to
Table 1.

device. Two kinds of metal thin layers were preparedsuccessively on the sand-blasted rough surface of asilicon wafer: the first layer was obtained withelectron-beam evaporated Ti and the second Au-Sb
layer was obtained by resistance-evaporation of apellet of Au containing a small quantity of Sb.
After deposition, the samples were alloyed in N2
atmosphere. Total amounts of Au and Sb in thesamples were determined by neutron activation
analysis. In the RBS, incident ions of 4oAr 4+ (50
MeV; beam current, several nA; beam spot, 1.5mm; measurement, 10-60 min) were used. The
arrangement for RBS measurement is shown in
Fig. 1.
(3) Results
The backscattering spectra of samples 3-5 are

Samples used in the present study.

No.

Si surface

Treatment

1.
2.
3.
4.
5.

mirrormirrorsand-blasted
sand-blasted
sand -blasted

as evap.
alloying
as evap.
alloying
alloying

Analyticalsurface
metal
metal
metal
m etaletchedsurface* Values obtained by neutron activation analysis.

Fig. 1.

Experimental arrangement.

Contents of
Au and Sb*}

Au~2500±100 }lg/g
Sb=

23 ±

1 pg/g} Au = 15.5+0.8 pg/g
Sb= 2.3 +0.1 pg/g

K. Ikeda, et aZ.

102

Sample No. 5

i"'~~
~

No.4

10J

U1
I-

Z

:::>

a

<..)

No.3
512

CHANNEL NUMBER

Fig. 2.

RBS spectra of Au (Sb) layer.

Sample No 5

• Au
&

Sb

>-

1=
<f)
z
w
o
0

5

~

o
~

•
•••
• • & /'-&

&&&&

&.
&

O~--~~~10~O=O~~~~5~O~O~~~~O~------~

DEPTH (nm)Fig. 3. Au and Sb depth profiles of sample S. Au-rich layer
was etched off with HF and aqua regia.

shown in Fig. 2. The thickness of the Au (Sb) film,
estimated from sample 1, is 73 nm, in good agreement with that of 72 nm obtained from neutron

activation analysis. As for sample 4, Au was considered to diffuse into silicon to 750 nm as a resultof alloying, with a peak Au concentration of
1.2 X 10 22 atoms/cm 3. When the Au-rich layer ofsample 5 was etched with HF and aqua regia, wellseparated spectra of Au and Sb were observed as
expected. Figure 3 shows the depth profile of Au
and Sb from the surface of the substrate after etchingas calculated from the spectra of sample 5. Figure 3
indicates that Au and Sb are spread to a depth ofabout 600 nm with peak concentrations of 1.2 X 10 20
and 2.3 X 1019 atoms/cm 3 , respectively. As for Sb,
the region with a concentration of more than 1018
atoms/cm 3, a value sufficient for forming an ohmic
contact, extends to a depth of 430 nm.
I t was shown that the depth profile of the heavy
metals under a rough surface can be determined by
RBS just as under a mirror-flat surface. This is aclear advantage of RBS over SIMS.

103
RIKEN Accel. Progr. Rep. 18 (1984)

111-2-31.

Depth Profiling of Deuterium in Titanium Carbide by
Elastic Recoil Detection Analysis
T. Kobayashi, S. Hayashi, H. Sakairi, M. Iwaki,
M. Aratani, M. Yanokura, and S. Oohira

As a part of the study on the behavior of hydrogenin titanium carbide, a depth profile of deuterium
implanted into TiC was obtained by the elastic recoil
detection analysis (ERD). A TiC foil of about 1 pm
thickness was prepared by a reactive ion plating
method. The plating was performed by depositing
Ti ions on an aluminum substrate at 300°C in C 2H 2
of a partial pressure of about 2 X 10-4 Torr under abackground pressure of about 5 X 10- 6 Torr. An
analysis of the sample composition is now in preparation.
Deuterium implantation was carried out by using
the RIKEN 200 kV Low Current Implanter.
Instead of D+ ions, molecular ions D 2+ were used
to avoid mixing of H2+ ions. Energy of D 2 + ions was
50 keY, which corresponds to 25 keY for D+ ions.
The implantation was performed with an ion fluxof 1.25 X 1012 D 2+/cm 2 ·s to the fluence of 5 X 1016
Djcm 2 at 1 X 10-6 Torr at room temperature. The
beam was analyzed magnetically and scanned electrically across the surface for uniform lateral distribution of the implants. A raise in the sample
temperature during implantation was not monitored
but considered to be negligibly small because theinput power density was 10 mWjcm 2•
The D-implanted TiC sample was, after being
kept at room temperature for two weeks, analyzed
by ERD with 50.45 MeV Ar4+ ions from the RILAC.
105~------------------------------~

Surface (H)nSurface (D)[J

Channel number
Fig. 1. Energy spectrum of Hand D ions elastically recoiled
from the D implanted TiC obtained with 50.45 MeV Ar4+
ions. Scattered Ar ions and recoiled Ti and C ions were eliminated by an aluminum absorber placed in front of the detector.

0.96,-----------------------------,
0.80

Surface (D)l}Q)

2 0 .64ro.s::u

2'0.48c::J80.32 i=--"""""--'"Y'cN'U'''''''---

0.16
O~~~~~__~~~~~~~~

200

328

Channel number
Fig. 2. Deuterium region of the spectra: the lower, first run;the upper, second run.

The experimental arrangement was almost the sameas described in a previous report. 1) Since scattered
Ar ions and recoiled Ti and C ions were absorbed by
a 20 pm thick aluminum foil placed in front of thedetector, only recoiled Hand D ions were detected.
An energy spectrum of recoiled Hand D ions isshown in Fig. 1, from which depth profiles areconcluded to be almost Gaussian for deuterium anduniform for hydrogen. It is considered that a large
quantity of hydrogen atoms were dissolved in thesample during plating.
Figure 2 shows the spectra for deuterium obtained in the first and the second runs with thesame sample. To obtain each spectrum the sample
was irradiated with 50. 45 Me V Ar 4+ ions of 20 nA,
which corresponds to 2 X 10 12 Ar 4 +/cm 2 ·s, and of afluence of 1.6 X 1015 Ar/cm 2. It seems that the distribution of implanted deuterium was hardly affected by such irradiation. By assuming that a
deuterium content in the implanted sample waspreserved during the experiment, a hydrogencontent is estimated from the deuterium content.
On the assumption that the TiC sample has astoichiometric composition, a hydrogen content was
found to be 8 at. %.
Further experiments are planned to study a possible use of implanted deuterium as a standard
for the quantitative analysis of hydrogen in TiC.
Reference
1)

H. Nagai, M. Aratani, S. Hayashi, T. Nozaki, M.
Yanokura, I. Kohno, O. Kuboi, and Y. Yatsurugi:
RIKEN Accel. Progr. Rep., 17, 102 (1983).

104
RIKEN Accel. Progr. Rep. 18 (1984)

111-2-32.

Stress-Induced Site Change of H In V Observed by
Channeling Experiments

E. Yagi, T. Kobayashi, S. Nakamura, Y. Fukai,* and K. Watanabe*

Recently, Suzuki et al. l ) reported that the
diffusivity of H in V is enhanced enormously by
application of tensile stress along a < 1 1 1 >direction, and concluded with the help of their
Huang scattering experiments that it is a consequence of stress-induced site change T --+4T.
However, their observation of "superdiffusion of
4 T -hydrogen" has since been questioned by
Metzger 2 ) and Schober and Golczewski,3) and still
remains in dispute. The objective of the present
paper is to report our first results of channeling experiments on H in V, especially on stress-inducedsite changes which, we believe, are closely related
to the observation of Suzuki et al.!)The lattice location of hydrogen was determinedby utilizing the nuclear reaction IH(l1B, a)aa.
Because of the low sensitivity of this reaction forhydrogen detection, the concentration was chosen
to be VH O. 1 (a-phase). Specimens were cut from a99.950/0 pure single crystal into discs of 1.5 mm thickand chemically polished. In order to introduce hydrogen up to the concentration VH O. 1 without
ever forming jj precipitates before observation,hydrogen was charged electrolytically into one halfof the disc (serving as a reservoir) up to the average
concentration of VH O•2 , and was subsequently
diffused into the remaining half (serving as a
specimen) by heating the crystal on a target holder
up to 150°C, a temperature well above the a-(a+ jj)
phase boundary ("-' 110°C) for the composition
VH O. 1 • To ensure homogeneous distribution ofhydrogen, channeling experiments were performed
at 150°C after holding the specimen at ·t his temperature for 24 hr.
The collimation of the incident 11 B2+ beam (2.02
MeV) was better than 0.057° for a {1 11} planar
channel, and 0.076° in other cases. The crystal
orientation was set to within ±0.004°. The 11B2+
beam was 1.0 mm in diameter with current of
about 1 nA. Both a particles and backscattered 11 B
were measured as a function of angle between the
direction of the beam and axial or planar channel.
More detailed results of the experiment were
described in our previous paper on H in Ta. 4)* Faculty of Science and Engineering, Chuo University.

Results of the angular scans for {1 0 O} and{1 1 1} planar channels are shown in Fig. 1. From
Fig. 1 it is unambiguously concluded that mostof H atoms are located at T (tetrahedral) sites. The
results on < 1 0 0> and < 1 1 0> axial channels
were also consitent with this conclusion.
After the measurements at 150°C described above,the specimen was cooled to room temperature at a
rate of 0.8 K/min and was kept there for 24 hr. It
was then reheated to 150°C at a rate of 0.35 K/min,and kept there for 24 hr before the anglular scan fora {1 0 O} channel was made. The result is shown in
Fig. 2. One of the most important findings of thepresent experiment is that the profile of the a-yield
is changed markedly by the heat treatment. Afterthe heat treatment, the profile consists of a wide
dip with approximately the same width as that of
the 11 B dip, and two shoulder peaks located atabout ±0.25 °. This result indicates that a major
proportion of H atoms occupies interstitial sites
displaced from normal positions of T sites. We
shall here assume, from symmetry considerations,that the observed profile originates from displaced -T (d -T) or 4 T configurations, in both ofwhich the position of maximum density of hydrogenis displaced toward the 0 (octahedral) site. The
displacement from the T site was estimated to be
0.44 A, which, in comparison with the T -0 distanceof 0.76 A, means that the position of a maximum
density is closer to 0 sites than T sites.
A recent theoretical calculation5 ) has shown that, .
as the vanadium lattice is elongated along one ofits cube axes (z-axis), the most stable self-trapped
configuration changes continuously: T --+ d-T --+4 T --+ Oz' Therefore, it is expected that the presenceof tensile stress, either external or internal, may
induce transition from T to d-T or 4T configurations.
In the present experiment, precipitation of the jjphase on cooling to room temperature is expected
to produce internal stress. The effect of internal
stress is evident in Fig. 2: The depth of the 11 B
dip, which recovers to only 75%) of its original value
after reheating, clearly shows that the internalstrain in the jj-redissolved state is appreciably larger
than in the virgin a state. In order to estimate the105

E. Yagi, et al.

1.5.----- - - - - - - - - - - - - - - - - ,{100 }

0

-l

W

1.0f-

>=

T

+\J'-

i

: .. ~

N

:J
<!

L

3 0.5 z

tf
0

0

0

-1

(b)

150'C

150'C

~ ~

d-T or 4T

0

V

1.0

-l

r
0

ff

fmf
T

0

• H

(0)

W

1m

0

I

-2

{100}

{111 }

.

@

1.5

w
::::;

N

f

«

2:

T

0::

I

2

-2

ANGLE

(deg)

-1

0

~ 0.5

2

Fig. 1. Angular profiles of a-particle and backscattered 11 B
yields across {1 OO} and {1 1 1} planes in VHO.l. The fullcurves and the dashed curves are drawn to guide the eye.
The insets indicate the projection of 0 and T sites (squares)
with their relative weights (numbers in the squares) on theplane perpendicular to the planar channel in question. Thelines represent the projections of atomic planes.

II]

T

0
-1

0

-1

0

ANGLE (deg.)magnitude of the internal stress introduced by
precipitation of the .a-phase, the X-ray diffraction
was measured on a single crystal specimen subjectedto the same thermal cycling process as in thechanneling experiment. The measurement of therms angular broadening of the (2 0 0) diffraction
line caused by precipitation indicates the rms
strain of 2.6 X 10-4 , and the internal stress of 1/4
to 1/3 of the elastic limit.
We conclude from these observations that theconfiguration of H in V is extremely sensitive tothe presence of stress: the transition T ~ d-T or
4T takes place at stress levels much lower than theyield stress. As the internal stress in the .a-redissolved a-phase is just comparable to the valuesof external stress at which the superdiffusion setsin,!) we may further conclude that the stress-

Fig. 2. A change of {1 OO} angular profiles of /3- and 11B_
yields in (a) the virgin a state (150°C), and (b) in the /3redissolved a state (150°C). The full curves and the dashedcurves are drawn to guide the eye.

induced configuration presently observed is responsible for the occurrence of superdiffusion.
More detailed results are described in Ref. 6.
References
1)

2)
3)
4)
5)
6)

T. Suzuki, H. Namazue, S. Koike, and H. Hayakawa:Phys. Rev. Lett., 51, 798 (1983).
T. H. Metzger: ibid., 52, 476 (1984).
T. Schober and J. Golczewski: ib£d., p. 478.
E. Yagi, T. Kobayashi, S. Nakamura, Y. Fukai, and K.
Watanabe: J. Phys. Soc. Jpn., 52, 3441 (1983).
H. Sugimoto: £b£d., 53, 2592 (1984).
E. Yagi, T. Kobayashi, S. Nakamura, Y. Fukai, and K.
Watanabe: Phys. Rev. B, 31, 1640 (1985).

106
RIKEN Accel. Progr. Rep. 18 (1984)

111-2-33.

Lattice Location of Hydrogen in Nb a-Phase as Observedby Channeling Method
E. Yagi, S. Nakamura, T. Kobayashi, K. Watanabe,* and Y. Fukai*

In a previous study, we have made the first determination of the lattice location of hydrogen in Ta
by the channeling method using a nuclear reaction
1 H(l1 B, a )aa and demonstrated that this method
is:useful to locate the hydrogen dissolved in metals l ) ;the hydrogen was detected by measuring emitted
a-particles. In the present study, this method wasapplied to locate the hydrogen in Nb a-phase.
Hydrogen was introduced electrolytically into
the one half of .a Nb single crystal disc in the same
way as in the 'case of V,2) and was diffused subsequently into the remaining half (serving as a
specimen) by heating the disc to 1SSoC on thetarget holder for the channeling experiment. The
hydrogen concentration was NbH o.l3 (a-phase).
The channeling experiment was performed at 1SSoC
by using a 2.03 MeV 11B2+ beam. Collimation of
the beam was better than 0.076°. Detailed description on the experiment was given in a previous
paper on H in Ta. 1) The results of angular scanon < 1 1 0> and {I 0 O} channels are shown in

Fig. 1. These angular profiles of the a-yields, i.e.,hydrogen yields, indicate that most of hydrogenatoms are located at tetrahedral interstitial sites(T -sites). (The positions of two subsidiary peaks
observed in the < 1 1 0> axial scan, located at±0.3So from the center, are consistent with theposition expected from the calculation for the Tsite (±0.34°).
After the measurement at ISSoC, the specimen
was cooled to room temperature and kept there for
24 hr. It was reheated to ISSoC, kept there for 24 hr,
and then angular scan was performed. This heat
treatment is similar to that made in the case of V. 2)
The results are shown in Fig. 2. Although thisthermal cycle made the dip of 11B-yield shallow,
angular profiles of the a-yield still exhibit a feature
characteristic of T -site occupancy. These results
lead to the conclusion that the lattice location ofhydrogen in the Nb a-phase was not changed by
the thermal cycle. This result is essentially different from that on H in Va-phase; the {I 0 O}

I

<110>

{lOa}

•H

I I

1.5

o

Nb

I~!'~

: " \~
Illj4f

I

\

..

9w

..

\-.~

,

'i-

>= 1.00

0.5

f f frn~
T

0

0

-4

-2

a

2

4
ANGLE

-2

-1

0

2

( deg .)

Fig. 1. Angular profiles of a-particle and backscattered 11 B yields across < 1 1 0 >axis and {1 OO} plane in NbHo.13. The full curves and the dashed curves havebeen drawn to guide the eye. The insets in the figure indicate the projection ofo and T sites (squares) with their relative weights (numbers in the squares) on
the plane perpendicular to the channel in question. The open circles and the lines
represent the projections of atomic rows and planes, respectively.
• Faculty of Science and Engineering, Chuo University.

107

E. Yagi, et ai.

<110>

I

{100}

•H

I I

1.5

o

Nb

9w
>-

1.0

0.5

~

0

-4

-2

0

2

Fig. 2.

-2

4
ANGLE

tmt

t0t

T

-1

T

0

2

(deg.)

Angular profiles of a- and 11 B-yields in the fi-redissolved a state in NbHo.13.

a-angular profile was changed markedly by the same
thermal cycle. 2) As described in the case of V, 2) mostof hydrogen atoms precipitate into the .a-phaseon cooling and the precipitates are redissolved
on reheating, but this process introduces an appreciably large strain into the .a-redissolved a-phase.
Comparison of the present result with that on H in
V which was subjected to the same thermal cycle
suggests that hydrogen location in V was changed
even when the {l 0 OJ llB-dip recovered to 75%
of its original value by redissolution of the ,a-phase,
while in Nb the hydrogen location was not changed
despite much smaller recovery of the {1 0 O} II B-

dip, i.e., only 35%. The observed fraction of suchrecovery may indicate that the thermal cycle introduces a much larger internal strain in Nb than in V.
Therefore the present result indicates that thelattice location of hydrogen is less sensitive to thestrain in the Nb a-phase than in the Va-phase.
References
E. Yagi, T. Kobayashi, S. Nakamura, Y. Fukai, andK. Watanabe: ]. Phys. Soc. Jpn., 52, 3441 (1983).
2) E. Yagi, T. Kobayashi, S. Nakamura, Y. Fukai, and K.
Watanabe: Phys. Rev. B, 31, 1640 (1985).

1)

108

RIKEN Accel. Progr. Rep. 18 (1984)

111-2-34.

Compositions of Anodized Aluminum with
Europium Implantation
M.lwaki

Aluminum substrates doped with transition metals
or rare-earth metals show an electroluminescence
proper to doped particles during formation of ananodically oxidized film in solution. For example,
AI-1 %Mn alloys show bright yellow electroluminescence during anodization in the ammonium
pentaborate solution. On the other hand, luminescence of aluminum implanted with phosphors
has not yet been investigated. Recently, we observed
the reddish-orange electroluminescence emitted
from europium-implanted aluminum surface during
anodization in the ammonium pentaborate solution.
In the present work, compositions of europiumimplanted aluminum sheets after anodization areinvestigated by means of a He+ backscattering
technique.
All specimens used were 4 N aluminum sheets(Toyo Aluminum Co., Ltd.). Before ion implantaI

.. 8
.~

120

6 \
;.

80,2

·'--Eu

c
:J
o

.f.

,

U

..

40

\

o'-----'-_"----'-_'-----'-__ ..l...j~~..
40

80

120

160 180

I

220

0
260

r'._

Channel number

Fig. 1. Backscattering spectrum of europium-implanted
aluminum anodized in ammonium pentaborate solution.

tion, they were immersed in a 5% NaOH solution
for 2 min and rinsed with de-ionized water. Ion
implantation was performed to a dose of 5 X 1014
Eu/cm 2 at 100 keV at room temperature. Anodic
oxidation of europium-implanted aluminum wascarried out in the 0.1 M ammonium pentaborate
solution at about 20°C. At a constant current
density of 15 mA/cm 2 forming voltage was measured. During anodization, the implanted regionof the aluminum surface emitted electroluminescence characterized by Eu+3 •The Rutherford backscattering measurement was
carried out by using 1 MeV 4He+ with a fluence of
5 pC to estimate the compositions of surface layersof aluminum. Backscattered particles at an angleof 1500 were detected and analyzed by using asolid state detecter and conventional electronics.
The samples were mounted on a goniometer in atarget chamber below 3 X 10-4Pa.
Figure 1 shows the spectrum obtained for backscattered particles from europium-implanted aluminum anodized in solution. The arrows of channel
numbers 50, 90, 141, and 234 correspond to theenergy edges of boron, oxygen, aluminum, andeuropium at the specimen surface, respectively. It
was found that implanted europium atoms make agaussian distribution near the surface layer. The
ratio of aluminum to oxygen atoms is about 2: 3,
but the amounts of boron atoms are unexpectedly
larger than those of aluminum atoms by one orderof magnitude. It is considered that the boron atoms
were doped into an aluminum sheet during anodization in the ammonium pentaborate solution.

109
RIKEN Accel. Progr. Rep. 18 (1984)

111-2-35.

Surface Compositions of Argon-Implanted Kapton Films
M. I waki and K. Yoshida

Ion implantation has been widely employed inmodifying materials because of its ability to introduce a controlled amount of particles into a target.
However, studies on its application to organic materials were rather few and the effects of ion implantation on organic materials were not known well.
Recently, Kapton films have been implanted with avariety of ion species and an electrical conductivityof implanted polymers has been measured as functions of energy and dose. The results showed thatpolymer films irradiated to high doses at energies of
0.3-2 MeV exhibit metallic luster and low resistivities of about 5 X 10~4Q·cm. The ion energies usedin these experiments were higher than that utilized
normally for ion implantation, e.g., 50-200 keY.
Recently we have found that a Kapton film implanted with 150 keY Ar ions forms a highly conductive surface layer with metallic luster. The
present report describes a preliminary result of a
Rutherford backscattering measurement on thesurface compositions of argon-implanted Kapton
film.
Argon-implantation in the Kapton film was performed to a dose of 1 X 1017 Ar/cm2 at an energy of
150 keY. In order to prevent films on a target
holder from temperature elevation, the implantedarea was reduced less than 10 mm in diameter bymasking the film with an aluminum sheet and theion-beam current density was lowered to less than
1 pA/cm2 •
7 ~..

""--.

6 "

.'.....

.

\

-120

.~

.

":

.

-

.~

80

.~.

..

.'

•c

-..

",.

1

. ...

('.

80

.. 120

::J

0

<.>

·Ar
.j

..

.;:<:..

160

2c

40
-

200

Channel number

Fig. 1.

Backscattering spectrum of argon-implanted Kapton.

The Rutherford backscattering measurement wa's
carried out by using 1 MeV 4He+ with the fluenceof 5 pC. Backscattered particles at an angle of 150
were detected and analyzed by means of a solidstate detector and coventional electronics. The
samples were mounted on a goniometer in a target
chamber, the pressure of which was below 3 X 10-4
Pa.
With increasing doses, the surface of the implanted Kapton films was colored and began toshow metallic luster at a dose of 1 X 1017 Ar/cm 2 •Figure 1 shows a spectrum obtained with backscattered particles from the argon-implanted Kapton
with matellic luster. The leading edge of carbon
atoms of the Kapton surface is at No. 59 channel
and the energy edge of argon atoms at the Kapton
surface is at No. 174 channel. The energies at No.
59 and 174 are 0.273 and 0.687 MeV, respectively.
Kapton is an organic polymer containing large
amounts of nitrogen and oxygen atoms. If nitrogenand oxygen atoms exist, the energy edges of nitrogenand oxygen atoms at the Kapton surface are 0.333
and 0.385 MeV, respectively, which correspond to
No. 76 and 90. The backscattering spectrum indicates the absence of nitrogen and oxygen atoms in
the Kapton surface layers. The result suggests thatargon-implantation decreases the densities of nitrogen and oxygen atoms in the Kapton surface
layers; it is considered that argon-implantation
results in decomposition and carbonization in the
Kapton surface layers.
Moreover, the spectrum shows that the numberof the argon atoms retained in Kapton is smaller
than the imp1anted dose by two orders of magnitude .
The phenomenon will be explained as out-diffusionof argon atoms during or/and after argon implantation.
The decomposition and carbonization of Kapton
surface layers and out-diffusion of implanted argon
is considered to play a significant role for electricalconduction of Kapton.
0

110
RIKEN Accel. Progr. Rep. 18 (1984)

111-2-36.

Lamp Annealing of Cd-Implanted GaP
K. Aono, M. Iwaki, and S. Namba

Lamp annealing of disordered semiconductors isa relatively new field of semiconductor device physics. It is an extremely rapid and efficient method
for recrystalization of ion-implanted semiconductor
wafers by transient irradiation with tungsten halogen
lamps. In the present work, the effects of lamp annealing on the depth profiles of Cd atoms and radiation damages in Cd-implanted GaP have been
investigated by means of 1.5 MeV He+ channelingtechnique using the TANDETRON.
Substrates used were 0.1 Q. cm S-doped (1 1 1)
GaP wafers. The Cd implantation in GaP was per-----------..

.....

" \ Ga surface
\
\
I

I
I
I

"0
Q)

.!::!

I

ro

I
I

E
~

o

10 16 Cd +cm - 2
150keV

c:

(e)

400

500

Channel number

Fig. 1. Random (- - - -) and < 1 1 1 > aligned ( - ) spectraof GaP implanted with Cd. (a), as-implanted; (b), annealed
500°C for 3s; (c), annealed 750°C for 3s; (d), annealed 900°C
for 3s; (e), un-implanted.

formed at doses of 1013-10 16 Cd+cm- 2 at 150 keY
in the random direction. For annealing, the GaP
wafers inserted between two 3-inch Si wafers were
held in inert atmosphere, thermally isolated fromthe wafer cooled base, and separated by quartz
plate from the air cooled lamps. Annealing was
carried out at the temperature range 350-900°C
for 3s. Channeling measurements were carried out by
using the 1.5 MeV He+ ions with a fluence of 2pC
cm- 2 • The specimens were mounted on a 3-axis
goniometer in a target chamber, which was kept atpressure below 5 X 10-6 Torr. Backscattered particles at an angle of 150° were detected and analyzed
with a solid-state detector and conventional electronics.
Figure 1 shows the random and the < 1 1 1>
aligned spectra observed for Cd-implanted GaP
with 1016 Cd+cm- 2 as a function of annealing temperature. The Cd depth profiles in the random andthe aligned spectra of as-implanted specimens are
Gaussian. However, in the scattering yields fromthe lamp annealed specimen, the random and thealigned spectra showed that Cd atoms moved
inward and/or foward. Radiation damage in Cdimplanted layers was investigated from the spectra
obtained from Ga in GaP as shown in Fig. 1. As
the annealing temperature becomes high, backscattering yields of the aligned spectra decrease
and then the peak was shifted toward the surface.
The result shows that recrystallization of Cdimplanted GaP occurs from the deep region toward
the surface for the lamp annealed specimen.

-111
RIKEN Accel. Progr. Rep. 18 (1984)

111-2-37.

Helium Bubble Formation In Ni

Y. Higashiguchi, * E. Yagi, Y. Suzuki, * and H. Kayano*In the present study, the relation between the He
bubble formation and the grain growth was investigated in a He-injected Ni. Specimens were 99.990/0
pure Ni sheets of 0.3 to 0.5 mm in thickness. 36 MeV
a-particles were injected into the specimens atroom temperature by two methods: by setting anedge-shaped graphite degrader in front of thespecimens to ensure the uniform depth distributionof helium, and without the degrader. Total helium
doses were 4.0 X 1020 He-ionsJm 2 in the former and
Irradiated surface

8.0 X 1019 He-ionsJm 2 in the latter.
Both Ni specimens injected with and without thedegrader ' were annealed at 1,073 K for 100 hr in 'a
vacuum. The cross section cut in ' the plane per'pendicular to the beam-incident surface was' observed by optical microscopy after polishing andchemical etching. The results on the specimens irradiated with the degrader and without the degraderare shown in Fig. 1 (a) and 1 (b), respectively.
In the specimen injected without the degrader, thedefect band, which consists of high density of He
bubbles and irradiation-induced defects such as
loops and dislocations, was observed just at thedepth of projected range of 36 MeV a-particles(Fig. 1 (b)). In the specimen injected with thedegrader, the He-injected region and the uninjected
region, which were bounded at the same depth as

100 pm(a)(b)

Fig. 1. Opticalmicrographs of the structure observed after
annealing at 1,073 K for 100 hr in Ni specimens injectedwith 36 MeV a-particles with the degrader (a) and without
the degrader (b).

E 20
::t.

15

Fig. 2. The change of grain size of a He-injected Ni specimen
as a function of annealing time at various temperatures.

* The Oarai Branch, The Research Institute for Iron, Steeland Other Metals, Tohoku University.

Fig. 3. Transmission electronmicrographs of a He-injected
Ni specimen observed after annealing at 1,423 K for 51 hr.

112

Y. Higashiguchi, et al.

that of the defect band in Fig. 1 (b), exhibit themarked difference in the grain size (Fig. 1 (a));
the grain size is small in the uniformly He-injected
region and very large in the uninjected region.
The grain size in the He-injected region was nearly
equal to that in the virgin state before injection.
This result indicates that helium atoms or small
bubbles prevent the grain growth during annealing
at 1,073 K for 100 hr.
In order to investigate this effect in more detail,similar observation was made after annealing at
1,273 K and 1,423 K in a vacuum. The result isgiven in Fig. 2. It is clearly shown that the incubation period exists in the grain growth process inthe He-injected crystal. Observation of He bubbles
was made by transmission electron microscopy.
The result obtained after annealing at 1,423 K for
51 hr is shown in Fig. 3. Small bubbles are observedin the matrix and large ones at the boundary.
The observed long incubation period for the grain
growth at elevated temperature is explained by considering the flow rate of He atoms and small bubbles
to grain boundaries, the flow rate of Ni atoms fromone side to another side of grain boundaries, and thatthe bubble faceting is a rate-determining process forthe bubble growth. The detailed discussion will be
described elsewhere.

113
RIKEN Accel. Progr. Rep. 18 (1984)

111-2-38.

Creep Property Improvement of Helium Injected JPCA by
Thermomechanical Treatments
N . Yamamoto, H. Shiraishi, H. Kamitsubo, 1. Kohno, and T. Shikata

It is well known that helium generated by (n, a)
reactions causes the deterioration of mechanical properties in the fusion reactor structural materials
because it accumulates at the grain boundaries
where it has a strong influence on intergranularfracture. Among a number of metallurgical approaches to reduce the deterioration, the method ofhelium trapping at TiC precipitates in the graininteriors has recently been considered most effective in the case of austenitic stainless steel. The
purpose of the present work is to clarify the effectof TiC distribution on the suppression of harmful
helium effects and to seek the best pre-irradiation
thermal-mechanical treatment in the Ti-modified
austenitic stainless steel.
The alloy used was Japanese Prime Candidate
Alloy OPCA: Fe- 0.06%C-16%Ni-15%Cr-2.4%
Mo-1.8%Mn-0.53% Si-0.240/0 Ti-0.027%P-0.0035
010 B), which is considered to be the first wallmaterial in the Japanese program for an experimental
fusion reactor. Three dIfferent pre-Injection
thermal-mechanical treatments were adopted for
different TiC distributions; [A] SA (1,050°C, 1hr); [B] SA (1,050°C, 1 hr)+A (800°C, 10 hr);[C] SA (1,050°C, 1 hr)+CW (20%)+A (750°C,
1 hr). The average size and number densityof TiC in each treatment were 50-100 nm; 1018
njm 3 [A], 37 nm; 3 X 1020 njm 3 [B], 5 nm; 1 X 1022
njm3 [C], respectively. Helium was uniformly in-400

jected all over the specimen depth at 650°C by aparticle irradiation. The injected helium content
was about 50 at. ppm. The creep rupture tests werecarried out on the uninjected and injected specimens
at 650°C in flowing argon gas of 99.998% up purity.
The fractography by a scanning electron microscope (SEM) and microstructure observation by atransmission ele.ctron microscope (TEM) were madeon the fractured specimens.
Figure 1 shows creep rupture curves of helium
injected and uninjected specimens. Helium caused
a reduction in creep rupture strength, although theextent of the reduction varied in three treatments.
The reduction in treatment A amounted to about
150/0 of the uninjected values, while there was almost
no change in treatments Band C. These results
indicate that the presence of intragranular TiC
precipitates before helium introduction appreciably
improved the creep rupture strength of the heliumcontaining material.
The creep rupture elongation is shown in Fig. 2
as a function of the creep rupture time. The valuesof the rupture elongation were considerably spoiled
by helium in all three treatments. The extent of
the deterioration was almost the same and amounted
to about 50% of the uninjected values. Fractographs
by SEM revealed that in helium free controls thefracture occured perfectly in transgranular ductilemode, while the helium injected specimens partially

JpCA

JPCA
30

~.

300

~

rn

c
o
W

(f)
(f)

~
i7i

20

:;

10

0

0

0

--------------------0-- ----------

<l!

g. 10

200

650°C

o
______ o--o----=o--o~---oo--J•. 0::.J°••---- ------

0:

(:,

-A.-.-.-.-.-.-.-.-.-.!:...(:,-.-~-A..A

100

10

Time

1000

(hr. )

Fig. 1. Creep rupture curves at 650°C for thermomechanically treated JPCA in which helium was uninjected andinjected to 50 at. ppm.

A._~~._~ • .L

0~~~~1LO--J-J-LLLU1~0-0--~~~~10~0~0~

Time

(hr.)

Fig. 2. Rupture elongation curves at 650°C for thermomechanically treated JPCA in which helium was uninjected
and injected to 50 at. ppm.

114

N. Yamamoto, et al.

Table 1. Microstructural data from helium injected and creep ruptured specimens tested at 650°C «(J: applied stress, tr:creep rupture time, and F: percentage of helium bubbles trapped in the matrix).
Helium bubble
Preinjection
treatment

(J
(MPa)

G . B.

MatrixCreep data(hr)

Averagesize(nm)

Numberdensity(m- 3 )

Averagesize(nm)

Numberdensity(m- 2)

237

17:2

15.8

1.2 X 10 20

18.4

1.1 x 1014

207

106.7

23.6

1.4 x 10 20

14.8

1.4 X 1014

tr

A

F*

(%)

TiC
(in the matrix)
Average
Numberdensitysize(m- 3 )
(nm)

79
(72)

29.5

3.7 X 10 20

77

40.5

2.1 x 10 20

(91)
200

234.9

23.8

1.7 x 10 20

191

491.3

15.3

2.9 x 10 20

306

137.1

10.5

1.6 x 10 20

1.7 x 1014

77

67.1

4.3 x 1019

11.2

2.1 x 1014

(87)
82
(91)

73.1

5.9xl0 19

12.4

4.9 x 1013

92

7.5

1.1 x 10 22

6.1

9.7 x 10 21

18.1

B

(8~)

C
293

146.8

10.2

2.1 x 10 20

10.5

6.2 x 1013

92
(92)

* The values in the parentheses indicate calculated percentages of helium atoms trapped in the matrix.
showed intergranular brittle fracture in all treatments. These observations provide direct evidence
for helium embrittlement.
The TEM examination was made mainly to study
the morphology of helium bubbles. There existed
a few bubbles larger than 100 nm on M23C6 and/or
Laves phase at grain boundaries, which should be thecrack nuclei of intergranular fracture. Smaller bubbles were also distributed at the grain boundaries andin the grain interiors. Plenty of smaller ones weretrapped at the interfaces of the precipitates. Especially, almost all bubbles in the matrix were trappedat TiC precipitates. The results of quantitative
observations are presented in Table 1. It is note-

worthy that in spite of the wide variety of dispersionof intragranular TiC precipitates there was notmuch difference in helium bubble distribution
under all conditions both at the grain l::oundaries
and in the matrix. The percentages of intragranularly trapped helium bubbles were quite high andintragranular helium trapping by TiC precipitates
was almost achieved. But the creep rupture elongation was considerably reduced by helium. These
results indicate that there seem to be some difficulties
in suppressing the helium embrittlement only by
TiC precipitates and that structural strengtheningof grain boundaries themselves should be necessary
for further suppression of helium embrittlement.

115
RIKEN A~c~l. Progr. Rep. 18 (1984)

111-2-39.

Irradiation Creep of 316 Stainless SteelJ. Nagakawa, H. Shiraishi, H. Kamitsubo, I. Kohno, and T. Shikata
Type 316 stainless steel is one of the most usefulalloys for use in core structure of fusion and fastbreeder reactors. However, metals including stainless steels are responsible for acceleration of creep
deformation on bombardment with energetic particles like fast neutrons or high energy ions (creep
is slow, steady plastic deformation under relatively
low stress). This phenomenon termed irradiation
creep is a serious problem to the nuclear reactors,
for it limits the planned operation through asignificant dimensional change on one hand, andit increases the reactor life time by enhancing stressrelaxation and consequently increases the fatigue
life on the other. It is, therefore, essential for thereactor design to assess the irradiation creep behaviorof the reactor structural materials.
In the present investigation irradiation creep was
measured in situ under 16 MeV proton bombardment by using the cyclotron in a torsional creep
apparatus. Torsional creep measurement is not affected by the fluctuation of thermal strain associatedwith that of specimen temperature, which is a serious
problem in the ordinary tensile creep measurement.
Thus, this creep apparatus is capable of having very
high strain resolution, and the measurement of creep
strain with a low irradiation effect due to the low

beam current of the cyclotron was made possible.
Figure 1 shows the mechanism of the apparatus
schematically. Stress is applied on the wire specimen
by a controlled DC current through the torque coil.
Strain is measured by monitoring rotation of thesmall mirror by using a non-contact optical tracking
device. Emphasis was placed on the study of microstructure effects on the irradiation creep, and bothcold worked (high dislocation density) and annealed(low dislocation density) specimens were examined.
Figure 2 shows stress dependence of the irradiation creep rate. The slope of near unity indicates
proportionality of the creep rate to the appliedstress. The data with number "1" were obtained at
the first irradiation run of each specimen and they
deviate from a line extrapolat'ed from other data.
Figure 3 shows temperature dependence of the irradiation creep rate along with that of the thermal
creep rate (creep rate without irradiation). 1) Veryweak temperature dependence of the irradiation
creep is noticed in comparison with that of thethermal creep.
Linear stress dependence at relatively low str.ess
levels and temperatures as observed in the present
case is generally considered to favor the SIPA

#f/

10-9r-----~~--~~1~~~1----~~~

316SS
Irradiation creep- 16 MeV Protons
2.5X 10-8 dpa/ sf /hfi//c:y,-.///~~//;~'/~/~~~~/A

210-10 _

e

0.

Q)
Q)

u

-

/

/

-

/

10

T (·C) CW

A

200

0

300
350

A
[J

-- ---

10 -11 ' - -_ _.l..-.---''---'-.--L1---'-...........-'-'I______'I - - - - '10Fig. 1.

Schematic diagram of torsional creep apparatus.

20

50
100
Stress (MPa)200:300

Fig. 2. Stress dependence of irradiation creep rate for cold
worked (CW) and annealed (A) specimens.

J. Nagakawa, et al.

116

400
10- 8 500
I

Temperature rC)
300
200
j

j

d
316 SS(MPa)\ Irradiation
41
creep
83
. 16 MeV Protons\ 2.5 X 10- 8 dpa / s 124

10- 9

~\

CW A
t;.

0

----

~.

I

2

\

~.-"".:::-:::,6.:::,~
""

c.
(j)

\

:::----.
...... ......
'o~"...... t;.

.!!!.-

I-

~

(j)

-

W
I-

«

-

c::
a.. 10-14
w
W

c::

u

~"~~

0
10- 10 -600·C-------

0.........................

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

\ Thermal\,,

200MPa(P. Jung et al.)0

G =2. 5 x 10-

1.2

\

I

1.5

CONSIDERED' ....

NOT CONSIDERED

10-18 '--_.1-_..I....-_...I...-_....l.-_---L-_......J

1

1~

ldO

I

2.0
l / T (l0- 3K- l)

dpa/s

RECOMBINATION-DISLOCATION

10- 118(J= 100 MPa'.~"0,......

\

~
If)

2.5

Fig. 3. Temperature dependence of irradiation creep ratewith that of thermal creep rate.

(Stress-Induced Preferential Absorption of interstitials by dislocations) mechanism. 2) This model isbased on a climb motion of specific dislocations ofwhich stress field enhances interstitial absorption
through interaction with the strain field of interstitialatom and with the applied stress. The SIPA creep
rates were evaluated for 316 stainless steel and' theirdependence on dislocation density is shown in Fig.
4. Strong dependence is predicted only when therecombination of interstitials and vacancies is thedominant mode of defect loss. A rather small difference in the irradiation creep rate observed between the cold worked (dislocation density: . . . . . 3 X1015 m -2) and the annealed ( . . . . . 1 X 1012 m -2) specimens apparently rules out recombination. Calculated
temperature dependence of the SIPA creep rate (notshown) does not agree with the present result either,when the recombination is taken into account.
However, the magnitude of the calculated SIPA
creep rate is in the order of the in-reactor creep
rates measured at high accumulated damages (> 1
dpa: displacement per atom) but two orders ofmagnitude smaller than the observed creep rates atthe present low total damage «2x 10-3 dpa).

10~

1d 6

DENSITY (m- 2 )Fig. 4. Calculated dependence of SIPA creep rate on dislocation density.

An unrealistically large stress effect on the preferential interstitial absorption by dislocations
must be considered instead of the effect estimatedon the basis of the elastic theory in order to explain
the present creep rate results. Even in the in-reactor
creep cases, there is a region at the onset of irradiation (primary in-reactor creep) that shows a creep
rate one to two orders of magnitude higher than thesteady-state creep rate at higher accumulated
damage. Thus, it seems that not the recombination
but the SIP A mechanism should be re-examined in
the first place.
In ,conclusion, the SIPA mechanism can hardly
explain the irradiation creep rates of 316 stainlesssteel under proton bombardment and also in thein-reactor neutron irradiation when the total accumulated damage is still very low. The present
results indicate that a new irradiation creep modelis necessary at an early stage of the irradiation where
accumulated damages is still low.
References
1)

P. jung, C. Schwaiger, and H. Ullmaier:}. Nucl. Mater.,

85/86, 867 (1979).
2)

P. T. Heald and M. V. Speight: Philos. Mag., 30, 869(1974).

117

RIKEN Accel. Progr. Rep. 18 (1984)

111-2-40.

Depth-Dependen~ Damage Profile in Stainless Steels

Irradiated with Ar- and N-ions
K. Shiraishi,* K. Fukai,* E. Yagi, T. Sawai,* and S. Hamada*The heavy-ion irradiation experiments havebeen performed to simulate the neutron irradiation
damage for fusion reactor materials. In the simulation study, precise estimation of the mean projected
range is required for microstructural observation of
the radiation damage. This experiment is carriedout following the study on depth dependent damage
profile in stainless steel irradiated with He-ionsaccelerated by the cyclotron.!)Samples of Type 316 stainless steel and steel
modified with titanium of 0.25 wt% were solutionannealed in a vacuum for 1 hr at 1,373 K and 1,473
K, respectively. After electropolishing, the 316
stainless steel samples were irradiated at ambient
temperature with monoenergetic Ar-ions of 40.5
to 50.1 MeV to a total dose of lAx 1020 ions/m 2 byusing the heavy-ion linac. Monoenergetic N -ionsof 57.0 to 86.7 MeV were irradiated to the 316 andTi-modified steels to a total dose of 1.6 X 1020
ions/m2 by using the cyclotron. The irradiatedsamples were electroplated with nickel on both
irradiated and back surfaces, and then sliced ina plane normal to the ion-incident surface. The
sectioned sample was mechanically polished andsubsequently etched with a saturated solution of
CuCI in aqua regia. The specimen for transmission
electron microscopy was prepared by electropolishing to perforation after punching the sectioned
sample. The cross-sectional microstructure was observed with an electron microscope operating at 200
kV. Post-irradiation annealing of the sectioned

sample was carried out for 1 hr at 1,023 K in a
vacuum.
An etched line parallel to the ion-incident surface
is revealed with optical microscopy at the surface ofthe sectioned sample as shown in Fig. 1 for the 316
steel irradiated with 45.7 MeV Ar-ions and 86.2
MeV N -ions. The distance of the etched line fromthe ion-incident surface measured on the photographare 6 and 40 pm for Ar- and N -ion irradiatedspecimens, respectively. In the calculation for 86.2
MeV N-ions injected into amorphous iron, peaksof the distribution curves for the damage rate andthe injected ions occur at depths of 39.6 and 39.8
pm, respectively; the peak positions agree closely
in both distribution curves. Thus, the center of theetched line shown in Fig. 1a approximates the mean
projected range for 86.2 MeV N-ions injected into
the 316 stainless steel, and the measured value of
40 pm is in good agreement with the calculated
value of 39.8 pm.
In the measurement of the mean projected range
by optical microscopy, uncertainty arises fromidentification of the ion-incident surface and anerror in the measurement is estimated to be about
0.5 pm. This error corresponds to the uncertainty
of 1.3% for the range of around 40 pm for 86.2
MeV N-ions injected into the 316 steel. However,this error of 0.5 pm is not so small compared withthe range of about 6 pm for 45.7 MeV Ar-ionsinjected into the 316 steel. Furthermore, the stopping power for Ar in the steel has not been evaluatedFig. 1. Optical microstructures of Type 316 stainless steel irradiated with 45.7 MeV Ar-ionsa) and 86.2 MeV N-ions b).

* Japan Atomic Energy Research Institute.

118

K. Shiraishi, et al.

correctly in the VICInIty of 50 MeV. Then, theagreement between the measurement and the calculation for the Ar-ions injected into the 316 steel
is not so well as that for N-ions injected into the.316 steel.
When the irradiated specimens are annealed for
1 hr at 1,023 K, the etched line appears distinctly
at the identical position with the as-irradiated specimens. Figure 2 shows the microstructure relevantto the etched line in the 316 steel irradiated with
45.7 MeV Ar-ions to 6.3 X 1019 ions/m 2 and annealedfor 1 hr at 1,023 K. The etched line observed by
optical microscopy is correlated definitely to theelectron micrograph (Fig. 2a). It is evident in thephotographs of high magnifications presented as
Figs. 2b and 2c that the damaged region indicatedin Fig. 2a contains rectangular plate-like precipitates and argon bubbles. The precipitates elongatedalong the < 1 1 0> direction in the matrix wereidentified to be M 23 C 6 type carbide from a selectedarea electron diffraction pattern. The distributionsof number density and average diameter of the
bubbles have peaks of 4.3 X 1022 /m 3 and 7 nm,
respectively, at the center of the damaged region.
This fact indicates that the argon injected into the
316 steel at ambient temprature stabilized Frankloops to induce the nucleation of the carbide at theloop during the post-irradiation annealing, as incase of helium in the steel. 2) The carbide is observed in the region where contains argon of exceeding 200 appm to form bubbles during theannealing.
Fig. 2. Microstructures in Type 316 stainless steel irradiatedwith 45.7 MeV Ar-ions and annealed for 1 hr at 1,023K.
Full-range electron microstructure a), details of the damaged
region showing' carbide precipitation b), and argon bubblesc).

References
1) ' K. Shiraishi and K. Fukai: J. Nucl. Mater., 117, 134(1983).
2) K. Shiraishi, K. Fukaya, and K. Fukai: ibid., 119, 268(1983).

119

RIKEN Accel. Progr. Rep. 18 (1984)

111-2-41.

Effects of Fast Neutron Irradiation on Insulating Materials
M. Yatsuhashi, * T. Suematsu, * H. Kobayashi, * I. Kohno,
M. Yanokura, S. Motonaga, and H. Kamitsubo

It has become indispensable to elucidate theeffects of fast neutron irradiation on insulating
materials, because development of fast breeder
reactors, controlled thermonuclear reactors, andhigh energy particle accelerators is being hurriedon.
Several kinds of insulating materials, such aspoly (vinyl chloride), cross-linked polyethylene,
ethylene-propylene rubber and silicone rubber,were irradiated by fast neutron from the 160 cm
cyclotron as reported previously. 1) The size of theirradiated samples was 5 cm X 5 cm in area and 1mm
in thickness; the maximum neutron fiuence was
2.6 X 1016 n/cm 2 • The effects of fast neutron irradiation were compared with those of r-ray irradiation by using a conversion factor of 1 rad = 1.3 X 108
neutrons, which was obtained from the value ofabsorbing coefficient of fast neutron in polyethylene 2),3).

After irradiation, changes in volume resistivity,
dielectric constant, and dielectric loss (tan 0) of
the samples were measured at first. Then, threetensile test specimens, JIS K6301No. 4 dumbbell
shape, were stamped out from the sample, and thechanges in tensile strength and elongation of thespecimens were measured.
Figure 1 shows absorbing dose dependence ofthe tensile strength and elongation of cross-linked
polyethylene (XLPE); results of 60Co r irradiation
are also shown. Up to a maximum dose of 2 X 108
rad (2.6 X 1016 n/cm 2 ), the change in tensile strengthis small and, although elongation is lowered, avalue of about 1200/0 is retained.
In this report elongation is defined as {(l-/o)/Io} X
100 (0/0)' 10 is original length between marked points
on the specimen and 1 is length when it is broken.
Figure 2 shows the absorbing dose dependence ofvolume resistivity and tan 0 ofXLPE sample.
Neutron fluence (n / cm2)

Neutron fluence (n/ cm2)
5

1016

2

I

I

I

1 0 18 r----'\r--r=------i---~--r---r---___.1 0

XLPE

5

~
c

o

=~'i'-84~~"2"'-" E'r-77• E'n - 83

:.::;
«l

~ 102

E

100 ~
«l

101.7

.....

Eu

o
"ai

VI

S 5

5

5

o

:su

E

-.......

~~'IT' r -84
2 !.------.. . ---~===-=--6.:r-,,-• ------.

·~n

c

..

'

2

'j5*

10- 1

- - - T'n - 83
Q)

VI

'iii
c

2

- ......... y T'r - 77............

~ 10

1!

E

5

:::s

5

iii

>

~

2

2

.2

10 L..---'\r.L--J..-_--'-_ _....L..-_....L..-_....L..-_---' 10- 2

o

Dose

Fig. 1. Mechanical properties of XLPE. E·r-84 indicateschange of elongation by r-ray irradiation measured in 1984
and T · n-83, change of tensile strength by neutron irradiation
measured in 1983.

* Fujikura Ltd.

5

(Rad)

Fig. 2. Electrical properties of XLPE. tan 0 . r-77 indicateschange of tan iJ by r-ray irradiation measured in 1977 andp. n-83, change of volume resistivity (p) by neutron irradiation
measured in 1983.

M. Yatsuhashi, et al.

120

103r-~=---__________________- 'CJ Before iradiation
miitt,! After iradiation
r--

5 I-

XLPE

Fig. 3.

EPDM

PVC

SiR

Degradation of elongation properties.

Value of tan 0 is increased by 0.50/0 and volume resistivity is decreased to 1016 Q cm. The dielectric
constant was almost invariant by fast neutron ir-

radiation to 2 X 108 rad.
In Fig. 3 degradations of elongation property
for four insulating materials are shown. Degradation of electrical characteristics of poly (vinyl
chloride) (PVC) was large, but those of ethylenepropylene rubber (EPDM) and silicone rubber(SIR) were similar to those of XLPE.
The results of changes in the electrical and mechanical properties caused by fast neutron irradiation are similar to those obtained by 60Co r ray
irradiation. In conclusion, the irradiation effects
on the electrical and mechanical properties of theinsulating materials for electrical cables may not
be different appreciably between fast neutrons andr rays if absorbing doses are the same.
References
1)

2)
3)

H. Kamitsubo, r. Kohno, S. Motonaga, M. Yanokura,
T. Shikata, M. Yatsuhashi, T. Suematsu, and H. Kobayashi: RlKEN Accel. Progr. Rep., 16, 118 (1982).
A. E. Profio: Radiation Shielding and Dosimetry, WileyInterscience, New York (1931).
A. Charlesby: Atomic Radiation and Polymers, Pergamon
Press, London (1960).

121
RIKEN Accel. Progr. Rep. 18 (1984)

111-3.

Radiochemistry and Nuclear Chemistry1.

Isotope Production and Labelled Compound Synthesis
T. Nozaki, S. Ambe, M. Iwamoto, Y. Minai, M. K. Kubo, E. Tsuchida,
M. Yuasa, Y. Ogata, H. Nishide, M. Suehiro, and F. Yokoi
mechanism for this compound, the 15 0 tracer
technique is regarded as highly useful. Hence,
the uptake of 15 0 2 by this compound was firststudied. The 150 2 was supplied from a steady flow
gas line. A mixture of O2 (100 Torr) and 'N 2 (660
Torr) was conducted to a target cell and bombarded
with deuterons (8 MeV, 2 p.A) to induce the reactionof 14N(d, n)150. The crude 1502-02-N2 mixture
was passed through columns of copper powder andsoda lime (100 mm dia., 10 cm ,length) for removalof NO x and 17F formed by the radiation effect andby the 160(d, n)17F reaction, respectively. The gas
mixture was supplied with a steady flow (200ml/min) and a steady radioactivity intensity (1p.C/ml).
Before the measurement of the 150 2 absorption
by the sample, it was ascertained that: (1) the 15 0
was in sufficient radiochemical purity, (2) the ab~sorption saturation was attained in a few min when
the gas was bubbled into the sample solution, and (3)no notable isotopic exchange took place between the
15 0 and water. Oxygen uptake by the samples ofhemoglobin and the synthetic heme was measured
from the 15 0 radioactivity at the absorption equilibrium. The results are shown in Table 1. Eachvalue was obtained as an average over 10 samples.
The heme-bound oxygen was also determined
spectrophotometrically; the results are shown in
Table 1 together with those by an O 2 probe method,

In this period, the following studies have been
undertak~n: (1) adsorption of 29AI by soils, (2)determination of oxygen chemically bound to hemoglobin and synthetic heme by 15 0 tracer method,(3) synthesis and in vivo behavior studies of 77Brbromoperidol, and (4) preliminary study of thelabelling by th~ malonic acid ester synthesis. Also,an automatic synthesizer of HC-methyl iodide wasfabricated in the Technology Division of ourinstitute.
We previously reported on the production of
29AI and its distribution in animal organs. 1) We
tried some utilization of 29AI, but its too short life
did not allow us to obtain any satisfactory result.
Recently, we have measured the adsorption of 29Al
by soils. Soils of different origins are suspended inwater, and no-carrier-added 29Al is added to thesuspension with various amounts of HCI. The resultant suspension is shaken, and an aliquot of itis taken at 4 to 5 min intervals and centrifugedrapidly. The supernatant liquid is withdrawn andits 29AI activity is measured. Relative rate andequilibrium of the adsorption are thus shown to bedifferent according to the origin of the soil. Further
study is in progress.
A liposomal heme was synthesized as an artificial
oxygen carrier by some of the present authors, 2)
and embedded in a bilayer of liposome with a radiusof 400 A. In order to study the oxygen transfer

Table 1.

Sample(Heme concn.)
Red blood cell(0.5 mM)(1.0 mM)
Liposomal heme
(1.0 mM)
Aqueous media a)
1502-N2 gas

Oxygen uptake by red blood cell and liposomal heme.
Oxygen uptake volume (ml 02/100 ml)

Annihilation
radiation
intensity(t=O, cpm/ml)

Standard
deviation
(%)

2,970
5,560
3,540
795
24,900Present
method02-probe

Spectroscopy

Relative (%)
Present method X 100
Spectroscopy

4.0
4.8

1.57
2.94

0.415
0.417

1.64
2.86

96
103

4.2
1.8

1.87
0.421

0.423

2.04

92

At 30°C, 760 Torr and p(02)=100 Torra) Aqueous media; distilled water, phosphate buffer solution, and phospholipid liposome solution.

T. Nozaki, et al.

122

0\ ~

F

_\

asH

C(CH 2 hN

Ij ~Br

Fig. 1.

Bromoperidol.

which gives onlY ,dissolved oxygen quantity. Moredetailed results of this study are described in Ref.

3.
Bromoperidol (Fig. 1), is thought to be one of
the compounds which bind specifically with dopamine receptors in vivo. This compound was labelledwith 77Br by way of Sandmeyer reaction. Aminoperi dol was diazotized, and no-carrier-added 77Br
was added to the diazonium solution together withcopper powder. The mixture was heated gradually
to 75°C in 15 min. Mter addition of a sufficientquantity of ammonia to the mixture, the productwas extracted with chloroform and separated fromthe major by-products chromatographically. Finally,
the 77Br bromoperidol was purified by inverse phase,liquid chromatography and its purity was ascertainedby thin layer chromatography. The 77Br bromoperiodol was administered intravenously to rats andmice, and the biodistribution was studied together
with a carrier effect on tissue uptake. The distribution of this labelled neuroleptic in the brain was
examined by radioautography.
These biomedical assessments have revealed thefollowing facts.
(1) Brain uptake 10-240 min after injection was
4-2.50;0 dose/whole brain, 9-60;0 dose/g of the tissue,

which was 27-63 times higher than the blood radioactivity level. The brain uptake was affected considerably by the specific activity and chemical purityof the compound.
(2) In the brain, the radioactivity was localized
in striatum, where a dopamine receptor density isthought to be high, and cerebral cortex. The distribution of the 77Br was also affected by the specificactivity and purity of the labelled bromoperidol;
low specific activity and low chemical purity resultin non-specific and uniform distribution in thebrain.
(3) The distribution of 77Br-bromoperidol intissues other than brain reproduced similar trend
to that of low specific activity 82Br-bromoperidol
reported by Vincent et aZ. 4 ) The addition of unlabelled compound to the labelled bromoperidol suggested that about 50 nmol, i.e., 1 mg/kg of bodyweight, is the maximum torelable dose for normal
metabolism. More detailed results of this study are
published elsewhere. 5)
References
1)
2)

3)
4)
S)

T. Nozaki, S. Ambe, M. Iwamoto, and Y. Minai: RlKEN
Accel. Progr. Rep., 15, 9S (1983).
E. Tsuchida, H. Nishide, M. Yuasa, E. Hasegawa, Y.
Matsushita, and K. Eshima:J. Chem. Soc., Dalton Trans.,
1149 (1984).
M. Yuasa, Y. Ogata, H. Nishide, E. Tsuchida, M. Iwamoto, and T. Nozaki: Chem. Lett., 11,1889 (1984).
S. H. Vincent, M. B. Sambhu, and A. G. Digens:]. Med.
Chem., 23, 7S (1980).
M. Suehiro, F. Yokoi, M. K. Kubo, M. Iwamoto, and T.
Nozaki: Proc. IAEA Conf. Labelled Comp. Radiopharm.
(1984), in press.

123
RIKEN Accel. Progr. Rep. 18 (1984)

111-3-2.

Charged Particle Activation Analysis

T. Nozaki, Y. Itoh, Y. Ohkubo, T. Kimura,
H. Fukushima, T. Abe, and T. Masui

Since the end of last year, charged particle activation analysis of carbon, nitrogen, and oxygen inseveral matrices has been undertaken by Japan
Analytical Chemistry Center by the use of thecyclotron. I) We have aided this semi-commercial
trust analysis, and about 200 samples in all havebeen analyzed this year. For the analyses of carbon
and nitrogen by the reactions of I2C(3He,a )lIC
and I4N(p,a)lIC, respectively, an improved
method was devised for the chemical separation of
the HC last year. This method consists of (1)matrix dissolution in an alkali solution containing
a carbonate carrier, (2) the addition of KMn04 to
the solution and its heating in a microwave oven
until the dried mass becomes dull red, and (3) the
evolution of HC0 2 from the resultant mass and its
conversion into Li 2 CO a precipitate.
Silicon containing HC without other radioactivity
was used to check on this chemical separation,
because some uncertainty still existed in whether
any correction was necessary in the measured
carrier recovery due to contamination from nonradioactive CO 2 and whether the HC in the sample
silicon was totally mixed with the carrier. Silicon
doped with boron was bombarded to give lIC by the
HB(p,n)lIC reaction, and induced positron activities were measured nondestructively. After the
decay of 30p (2.5 min half-life) formed by the30Si(p,n)30P reaction, the sample was subjectedto the chemical separation. From the radioactivities
of HC in the sample just before the separation andin the separated Li 2 CO a together with the weightof the Li2 CO a, correction factor for this chemical
separation was found to be 1.15±0.07. This method
is now used routinely.
The fabrication of a new apparatus for surface
oxygen analysis considerably delayed, and our planalso delayed. The apparatus has recently been
completed, and the study has become in progressagam.
We reported on the escape of oxygen from meltof antimony-doped silicon in the last volume of thisreport. We wrote there that oxygen probably escaped
as antimony oxide. By thermochemical calculation,
however, this has been shown to be wrong. Now wethink with fair confidence that the evaporation of
antimony accelerates the evaporation of oxygen as

SiO just like in the steam distillation in which steam
flow accelerates the distillation of less vol,atileorganic compounds.
A reliable method is now urgently needed for the
analysis of carbon in gallium arsenide. ·- Charged
particle activation analysis with the 12C(3He,a)HC
reaction cannot be used for Czochralski GaAs
crystals, because they are crystallized under B20 3
melt and thus contains some boron. (Helium-3
bombardment of boron also gives HC by the IOB_
(3He,pn)HC reaction.) Hence, the use of 12C(d,n)I3N reaction is necessary for this purpose together
with a proper devise of the separation of the 13N.
We intend to undertake the following study
scheme for the establishment of the process ofanalysis: (1) preparation of 13N-doped GaAs foruse in the study of the chemical separation of
13N, (2) study for quantitative separation of the
13N from the matrix by dry fusion and its purification by passing through successive columns,(3) ascertainment of the quantitative absorption of
the 13N in a column, in a suitable state for activity
measurement, and (4) check on the reliability of theprocess and, if necessary, determination of the correction factor due to non-quantitative recovery of
the 13N.
For the preparation of 13N-doped GaAs sample
by recoil implantation, two GaAs plates wereplaced in parallel with a small aperture in whichan oxygen stream was bombarded with a proton
beam as shown in Fig. 1. Atoms of 13N formedby the 160(p,a)13N reaction are provided withrecoil energies, by which a part of the atoms are

nProton bean..u.

Fig. 1.

AI window

Apparatus for recoil implantation.

124

T. Nozaki, et aZ.

implanted into the GaAs plates. The plates were
found to contain also some other radioactivities,
such as those produced from matrix Ga and As by
the bombardment with scattered protons and 18F
formed by the 180(p,n)I8F reaction.
After bombardment with protons (1 pA, 10 min)of 11 MeV incident energy, at which this reaction
has a maximum cross section, a few times 105 Bq
of 13N was in the GaAs together with activities ofother radionuclides. This GaAs plate is very usefulfor the succeeding studies.
The 13N was found to be separated quantitatively
by fusion of the matrix with copper grains in ahelium stream. An RF generator of 2 kW maximum
power was used for heating. By passing the helium
stream carrying 13N through a column of Molecular
Sieve SA cooled with liquid nitrogen, the 13N proved
to be adsorbed quantitatively in a very narrow inlet

portion of the column, indicating the ease of themeasurement of 13N activity by the coincidence
counting of positron annihilation.
For the purification of the 13N in the helium
stream, a column of Molecular Sieve 4A wasinserted in the stream pass at the room temperature.
Although this column proved to be very effective
for the removal of radioactive impurities, it alsocaught a considerable portion of 13N . Various
columns are now under test for satisfactory purification of 13N.
Determination of implanted oxygen in silicon andits oxide is reported independently in this volume.
Reference
1)

T. Nozaki, Y. Itoh, M. Iwamoto, H. Shinyashiki, K.
Nomura, T. Kimura, and H. Fukushima: RIKEN Accel.
Progr. R ep., 17, 96 (1983).

125
RIKEN Accel. Progr. Rep. 18 (1984)

111-3-3.

Charged Particle Activation Analysis of lon-Implanted Oxygen
T. Nozaki, Y. Itoh, Y. Misawa, and T. Saito

Oxygen ion implantation for the formation of anoxide film in a solid has been studied for being applied, for example, to an Si02 layer formation insemiconductor silicon to separate its device elements.
Many papers have been published dealing with thedepth profile of implanted oxygen in silicon, without
any exact information about the quantitative amountof oxygen incorporated in silicon or other substrates.!) By the same experimental charged particle
activation analysis as was used for the determinationof oxygen in SIPOS film, 2) we measured quantitatively the amount of oxygen implanted into films
in order to obtain a relationship between the integrated ion flux impinging on the sample and thequantitative amount of oxygen incorporated in it.
Substrate plates used were of CZ silicon,< 1 0 0> orientation, and n-type with resistivity of
10 Q. cm. Oxygen ions or carbon monoxide ions of(1-10)x 10!7at·cm- 2 integrated flux were impinged
into these plates by the implantation technique. Also,
Si0 2 . film made on the plate by thermal oxidation

SiOz thickness (A)o 10002000300040005000 6000
/

~

/

/

50

o

/
/

e----e_e_
/

I

/

c

ro

/

40

>
:;:;

~V)

.....
C
::J

/

/

~]" 30f-

o
E

I

/

ro
'-+=,

.

/

VI

'Vi
'>,

20

;-

ro

c

Q)

tl.O

>.

10e ; .

x

o

O~

o 2

4

I

I

6

8 10 12 14

1IAmount of -oxygen
impinged (X 10 17 cm2)

Fig. 1. Oxygen concentration detected by activation analyses
vs. amount of oxygen having impinged. 0, Si02 without implantation; . , oxygen-implanted Si; l::,., carbon monoxideimplanted Si; e, Si02 film after oxygen ion impingement.

1.0~------------..

o

10

20

30

40

Duration of etching (~in)

50

Fig. 2. Depth profiles of oxygen in Si and Si02 films
observed by Auger electron spectroscopy. 0, Thermaloxidation film (500 nm in thickness); . , 7 X 1017 0+ cm- 2
implantation in Si; e, 7 X 1017 0+ cm- 2 implantation in
Si02.

was treated similarly. The total quantity and distribution of oxygen in these samples were measured
by charged particle activation analysis with the!60(3He,p)18F reaction , and by Auger electron
spectroscopy, respectively.
As shown in Fig. 1, all oxygen ions having impinged to the silicon plates were found to be incorporated into the silicon. Silicon plates after thermaloxidation to various thicknesses were used as theactivation standard. Carbon monoxide ions werealso shown to be incorporated quantitatively into
silicon. To the Si0 2 substrate, however, no oxygen
was found to be incorporated, only the quantityof oxygen in the Si0 2 before the implantation
being detected. As shown in Fig. 2, the depth profiles of oxygen also indicate that oxygen was incorporated quantitatively into silicon but almost no
additional oxygen was present in Si0 2 •References
1)
2)

K. Izumi, M. Doken, and H. Ariyoshi: lpn. l. Appl.
Phys., 19 (1) (suppl.), 151 (1980).
T. Matsushita, T. Aoki, T. Otsu, H. Yamamoto, H.
Hayashi, M. Okayama, and Y. Kawana: lpn. l. Appl.
Phys., 15 (suppl.), 35 (1975).

~26

RIKEN Accel. Progr. Rep. 18 (1984)

111-3-4~

Application of PIXE to Environmental Science

K. Maeda, y. Sasa, M. Maeqa,*, S. Nori~i,** anq M. Uda

A rapid, sensitive, multielemental analyticalmethod is required for investigating the materialbalance problems in environmental science. The
PIXE (Particle Induced X-ray Emission) spectroscopy is one of the advanced tools which meet sucha requirement. We report here the application of
the PIXE to settling particles in marine water,
together with some new aspects of the experimental
technique.
The experimental procedures and setups were described elsewhere 1),2) except that a tungsten electron
gun was newly set in front of the target to eliminate
the charging effect. When the target composed ofinsulating materials is irradiated by ions, it often
happens that positive charges are stored in the target
during irradiation. As a result, strong continuous
X-rays are generated and hence the sensitivity andthe accuracy of measurements become low. The
efficacy of the electron gun is demonstrated inFig. 1. The Ka peaks of S, Cr, and Mn are hindered. 105 , . . . . - - - - - - - - - - - - - - without electron shower

with electron showerby the superposItion of continuous X-ray background in the spectrum without the electron gun.
These peaks are detected clearly when the target isflooded with electrons.
Generally, light ions such as p and a particles
are used for excitation in the PIXE analysis. Few
studies on the PIXE by means of heavy ion impacts
have been reported in the literature. Then it isinteresting to compare the X-ray spectra inducedby light ions and heavy ions. We previously reported the analysis of the suspended particulates inwater of the Tama River. 3) For this purpose 15 MeV
N2+ ions alone were available to use for the excitation.
From the end of the last year, He+ and He 2+ ionsas well as N2+ have been accelerated by RILAC.
N ow the direct comparison of the light-ion andheavy-ion induced PIXE spectra becomes possible.
Figure 2 shows the concentrations of titanium andiron in the suspended particulates .determined byuse of ~ 1 MeV /amu N2+ and He+ ions, where thesame targets were used. The analytical results agreed
well with each other. The resolutions of the X-ray
peaks were somewhat better in He+ induced spectrathan in N2+ induced ·ones. The X-ray yields were,
however, much higher in N2+ impact than in He+
impact. This suggests that heavy ions are rather
preferable when the amounts of samples are extremely small.
The study on transportation of elements bymarine water is important to solve the mechanismsof geochemical material cycling. We have attempted
to apply the PIXE to the analysis of settling particles
in water of the Antarctic Ocean. Samplings were

~ :ill

o

Q)

A

~ 30

......
'd,20
;::I.

: 10

6

Channel Number

Fig. 1. PIXE spectra from clay (NBS standard 98a) inducedby 5 MeV He+ ions with and without electron shower.

* Tokyo University of Fisheries.
** Faculty of Fisheries, Hokkaido University.

A~400" ~~ ~ ~•0 I) '

R-: 200~

g

u...

I-

lif~--~1~OO~~~~~~-~4~OO~-r5~OOo......

o~~~~~~~~

I

I

I

Ii

~ 0-

,I

I

. River IlPUth .- Strecm°123456789
Ri ver nuuth +- Strecm

Scnpl1rg location

Smpl irg location

Fig. 2. Variations of concentrations of particulate titanium
and iron along the Tama River. 0: 5 MeV He+ impact, 1::,.:
15 MeV N2+ impact. See Ref. 3 as for the sampling conditions and the locations.

127

K. Maeda, et al.

Table 1.
Sampling
periodTotal flux and elemental concentrations relative to Si in settling particles in water qf the Antarctic Ocean.
Depth
(m)

Total flux
(mg/m 2 /day)

12/25-1/4
1/4-1/14
1/14-1/24
1/24-2/3

1,565

12/25-1/4
1/4-1/14
1/14-1/24
1/24-2/3

3,770Concentration ratio (by weight)
K/Si

Ca/Si

Fe/Si

Zn/Si

Sr/Si

900
2,540
460
320

0.00340.00280.00270.00100.01250.01570.01170.00800.00030.00020.00010.00030.00020.00020.00030.00030.00010.00030.00150.0001

600
2,230
760
480

0.00210.00330.00340.00320.01210.0101
0.02220.01890.00390.00040.00160.00290.00060.00010.00020.00030.00020.00010.00020.0001made four times between December 1983 andFebruary 1984 at the station located at 61 °30'8 and
150 02'E. The depth of the sea at this point is
3,920 m. Two samplers were arranged at the depths
of 1,565 m and 3,770 m, respectively. Settlingparticles were accumulated over a period of ten
days at each depth. A part of each sample wasdispersed in a small amount of pure water anddeposited on a Nuclepore filter of 1 mgJcm2 byfiltering, and then served as the target. The thicknessof sample itself was controlled to be 0.7 mg/cm 2 •Homogeneous thin targets with controlled thickness
were prepared by this method, but there is a possibility of underestimating water-soluble elements.
Improvement of the target preparation is in progress.
Chemical analysis of the same samples is to be
carried out in Hokkaido University.
The main component of the particles in the
Antarctic Ocean is, in general, considered to besilica from biogenic origin. Then we chose 8i as areference element. The concentrations of someelements relative to Si estimated from the PIXE
0spectra are summarized in Table 1 together withthe total flux of settling particles. Here 5 MeV
protons were used for the excitation. The total flux
was very large in the second sampling period. This
must be caused by a temporary blooming of planktons such as phytoplanktons. In all the sampling
periods, iron was enriched in the particles collected at the deeper region. This indicates that,during the sedimentation, Fe ions resolved in wateror contained in suspended particulates were caught
by the settling particles which had been generated
at the surface layer by biogenic reactions. The highconcentration of Sr at the upper region in the third
period is also noteworthy though the reason has
not yet been solved.
References
1)
2)
3)

K. Maeda and M. Uda: Reports I. P. C. R. (in Japanese),58, 96 (1982).
K. Maeda, Y. Sasa, and M. Uda: RIKEN Accel. Progr.
Rep., 17, 123 (1983).
K. Maeda, Y. Sasa, M. Maeda, M. Kobayashi, and M.
Uda: ibid., p. 132.

128

RIKEN Accel. Progr. Rep. 18 (1984)

111-3-5.

Application of PIXE to Medical Science (II)K. Maeda, H. Kusuyama, Y. Yokode, Y. Sasa,
S. El. N asr, * M. Kobayashi, and M. U da

The PIXE (Particle Induced X-ray Emission)is an advanced, extremely sensitive, multi elemental
analytical method. It is especially valuable foranalysis of small amounts of heavy elements inmatrixes composed of light elements such as organic
materials. In biological organs injured by diseases,
elemental compositions of affected parts might
differ from those of normal tissues. In some cases,
elemental compositions of blood, urine, and hair
reveal the indications of diseases; the PIXE isuseful for diagnosis. We have continued a study on
the application of this method to medical science.!)
We present here some examples of the PIXE analysis
of human tissues. We also report a preliminary experiment using a new Si(Li) detector designed foranalysis of light elements.
The details of the experimental procedures andsetups are described elsewhere. I) ,2) This year themagnet system for incident ion beams has been
improved. Now the scanning of ion beams of 0.5 X
0.5 mm 2 spot size is possible. Tissue samples were
freeze-dried and sectioned with a microtome toabout 10 p.m slices. Then they were placed on 1
p.m thick polypropylene film and used as targets
without any pre-treatments. For blood and blood
serum samples, we have examined several target

preparation techniques. Homogeneous thin targets
could be prepared by the following treatment:
liquid samples homogenized with an ultrasonic
generator are painted on polypropylene backing
film and dried in a vacuum desiccator.
Human tissues taken from patients of various
kinds of diseases have been analyzed. Deficiency
of iodine in diseased thyroid grands was reported
previously. I) The results of the PIXE analysis of theadditional samples has ascertained such a feature.
The most impressive is the case of renal adenocarcinoma. As Fig. 1 shows, the iron content in theactive cancer tissue is extremely high as comparedto the normal one. The Fe content in the necrosed
tissue in the cancer is between these two. On theother hand, the zinc content in' the cancer tissue ismuch lower than in the normal one. Table 1 showsthe elemental concentrations estimated from theindividual X-ray intensities in the PIXE spectra.
The enrichment factor of Fein cancer tissues isof the order of 10 to 100.
The change in elemental composition was also
recognized for the bladder cancer though it is not
so striking as the above case. Table 2 represents the
Ka peak intensities relative to the potassium Ka
obtained from the PIXE spectra of cancer and

5

10

(0)

Ct

~ 10'
c
~
u

Fe

Ct

Data No.2063Z

0.6 fJC

r;.e

(b)

(C)

Data No.Z0631

Data No.206X>

O.4BfJC

O.6fJC

X-Ray Energy {KeV}Fig. 1. PIXE spectra obtained from (a) active cancer, (b) necrosed, and (c) normal tissues
in a kidney taken from a patient of renal adenocarcinoma. 5 MeV protons were used for
excitation.

* Teacher's College for Women, Kuwait.

K. Maeda, et al.

Table 1.

129

Elemental concentrations in tissues of kidneys taken from patients of renal adenocarcinoma.
Elemental concentrations (flgfcm 3 )
P

CI

K

Fe

Zn

Case 1

Cancer tissue
Necrosis tissue
Normal tissue

3,000
5,000
4,000

2,600
2,000
2,100

3,200
4,100
3,500

8,500
2,100
73

49
70
110

Case 2

Cancer tissue
Normal tissue

3,700
3,100

1,700
1,700

3,900
2,800

660
64

41
100

Table 2. PIXE Ka peak intensities relative to K Ka obtained
from tissues in bladders. u: standard deviation.
Element

Cancertissue

P
S
CI
Fe
Zn

0.44
0048
0.80
0.00680.0016(u)(0.05 )
(0.11 )
(0.28 )
(0.0012)(0.0006)

Normaltissue
0040
0.70
2.13
0.00810.0026(a)(b)

NaF onmylar(u)(0.02 )
(0.18 )
(1.18 )
(0.0025)(0.0006)

normal tissues in bladders taken from five patients.
Potassium was chosen as a reference element because its concentration is constant in all the samples.
Chlorine and sulfur seem to decrease in the cancer
tissues while the concentrations of P, K, Fe, and Zn
are almost the same in both of cancer and normal
tissues.
Recently a new Si(Li) detector system has been
constructed. The detector has three windows:
open, a thin Parylene film, and a 7.5 pm thickberyllium foil. These windows are exchangeablein vacuum from the outside. The Ka X-rays of theelements lighter than Z = 13 can not be detected byan ordinary detector with a Be window because of
the absorption of X-rays in Be. By using the openor thin window, all the elements except Z= 1-3 canFig. 2. PIXE spectra of (a) Na3AIF6 on Al backing film and(b) NaF on Mylar backing film measured through the thinwindow. 5 MeV He+ ions were used for excitation.

be analyzed. Figure 2 shows the examples of the
PIXE spectra measured through the thin window.
References
1)
2)

M. Uda, K. Maeda, Y. Yokode, and Y. Sasa: RIKEN
Accel. Progr. Rep., 17, 134 (1983).
K. Maeda and M. Uda: Reports 1. P. C. R. (in Japanese),58, 96 (1982).

130
RIKEN Accel. Progr. Rep. 18 (1984)

111-3-6.

Reliability and Detection Limit for the Elastic
Recoil Measurement of Hydrogen

H. Nagai, M. Aratani, S. Hayashi, T. Nozaki, M. Yanokura,
1. Kohno, O. Kuboi, and Y. Yatsurugi

Elastic recoil measurement is usefull in theanalysis of hydrogen on or near the surface ofsolid,l)-4) The reliability of this method was checkedby comparing its results with those of other methods,
and the detection limit of hydrogen was investigated.
Experimental procedures are the same as in ourprevious studies,l),2) We used Ar-ions accelerated
up to 50 MeV, the beam current being 30-50 nA.
Nine amorphous silicon (a-Si: H) samples wereprepared by glow discharge of a monosilanehydrogen gas mixture, for the reliability measurement. Thickness of these samples ranged from 2,700

to 10,650 A. The hydrogen contents of these samples
were measured by the following three methods:
elastic recoil (ER), vacuum extraction (VE), andheat conductivity (He) measurements. The results
are shown in Table 1. Hydrogen contents of a-Si:
H samples were about 14 at. 0/0. The values determined by the ER method were in agreement withthose obtained by the VE and He methods to within
20% . Average ratios of hydrogen content obtained
by VE and He to that by ER were 1.02±0.13 and1.10±0.08, respectively. Thus these results in~icate that the absolute hydrogen content can be
determined fairly correctly by the ER method.

Table 1. Hydrogen contents in amorphous silicon samples measured by three methods: elastic recoil (ER), vacuum extraction (VE), and heat conductivity (He).
Thickness(A)

Sample No.

59-1-18-2
58-9-19-2
59-1-18-1
59-1-19-2
59-1-19-1
58-9-19- 2
58-9-09-1
59-1-19-3
59-1-19-4

10,650
8,950
8,300
6,720
6,500
5,260
5,100
3,100
2,700

(at. %)VE*

ER(' x 1017 2)(at. %)

7.48
7.42
5.59
4.24
3.75
4.00
3.50
2.37
1.82

13.0
16.2
13.7
14.4
14.0
17.4
11.7
16.7
15.9

atoms/cm

14.7
16.9
14.1
13.4
12.4
15.7
14.4
15.8
14.1

He

( x 1017 2)(at. %)

6.50
7.06
5.38
4.62
4.32
4.52
2.76
2.54
2.08

14.5

7.38

14.8
15.7
14.2

5.90
5.11
4.40

17.4
14.6

2.67
1.89

atoms/cm

(

X 10

17

)

atoms/cm 2

Average

VE/ER

HC/ER

0.87
0.95
0.96
1.09
1.15
1.13
0.79
1.07
1.14

0.99

1.02
±0.13

1.10
±0.08

1.06
1.21
1.17

1.13
1.04

* Measured by Dr. Ogawara (Science University of Tokyo)
Table 2.

Bulk and surface hydrogen contents in quartz, Si-wafer, and oxidized Si-wafer by elastic recoil measurement.
Bulk Hydrogen

Sample(at. ppm)(wt. ppm)

Surface hydrogen( X 1015 atoms/cm 2)

ES*
IR*
OX*#

1870±7078± 6289±22276±37
70±19
51± 6
S6±28
61± 7
22± 4
73±10

94 ±3
3.9±0.3
14.5 ±1.1
13.8±1.8
3.S±0.9
2.6±0.3
2.8±1.4
3.0±0.3
0.8±0.2
2.6±0.4

3.2 ± 0.2
S.0±0.3
10.0±0.7
4.6±0.S
10.3±0.3
3.1±0.7
9.6±0.3
S.9±0.2
13.7±0.S

Art.*#
Nat.*#
Si-SiOz**Si**** Quartz,** Si-wafer+Si02 (340 A),*** Si-wafer,# upper row, first measurement; lower row, second measurement

Ref.
Bulk Hydrogen (Content)
S. A.
(wt. ppm)

90 -130
0.2- 0.6
10 - 30

131

H. Nagai, et al.

10 7
E

10 6

~

~

Surface (2.53 MeV)It)~

Quartz+ 4o Ar (49.73MeV)............ 0 0
I I i "I ill i I"" I

10 5
Q5

c
c

co

10 4

Art.

..,C

0

'-..

2c 10 3
::I

0
()

10 2
10 1

ox
10°

00

256
Channel number

Fig. 1. The energy spectra of the hydrogen atoms recoiled by 49.73 MeV Ar-ions in thequartz samples (Art., Nat., and OX). The spectra were devided into three regions. Largepeaks of the recoil surface hydrogen atoms are observed in the higher energy region.
High energy edges of recoil oxygen atoms are observed in the lower energy region (deeper than 1.5 f.lm). Bulk hydrogen recoil spectra are observed in the 0.3-1.5 f.lm region
without interference.

For the determination of a detection limit,
natural and artificial high purity quartz samples(Nihon Sekiei Garasu Co.) were used. The results
are shown in Table 2. The bulk hydrogen contentsof the samples ES and OX were in good agreementwith the literature values, but the value of thesample IR was about 10 times greater than theliterature value. In addition, the apparent hydrogencontents in the bulk of low hydrogen samples, IR,
Art., and Nat., were correlated with the quantityof hydrogen on the surface. It is probable thatmeasured events in the energy spectra corresponding
to interior of samples (Fig. 1) are derived fromsurface hydrogen atoms which were recoiled andthen scattered into the detector with decreased
energies. To ascertain this, we made measurementswith a Si-wafer and Si-wafer oxidized by water
vapor (Hitachi Manufacturing Co.) as well as thethree quartz samples. The surface hydrogen contents of these samples were expected to be different
from one another. Results are shown in Table 2.
Though we expected to find a correlation or noncorrelation between the bulk and the surface hy-

drogen contents, we get a conflicting results. For
the quartz samples, while surface hydrogen amounts
vary by a factor of 2 to 3, the bulk values of second
measurements were in good agreement with theprevious values. On the contrary, the Si-wafer data
indicate that the bulk contents correlated with the .
surface amounts. We have not yet determined theeffect of surface amount on the bulk content precisely; further studies are in progress. At present,
the detection limit of this method is estimated to beless than about 200 at. ppm.
References
1)

2)

: 3)

4)

'H' Nagai, M. Aratani, T. Nozaki, M. Yanokura, I.
Kohno, O. Kuboi, and Y. Yatsurugi: RIKEN Accel.
Progr. Rep., 16, 125 (1982).
H. Nagai, M. Aratani, S. Hayashi, T. Nozaki, M. Yanokura, 1. Kohno, O. Kuboi, and Y. Yatsurugi: z'bz'd., 17,
102 (1983).
M. Aratani, H. Nagai, S. Hayashi, M. Yanokura, O.
Kuboi, Y. Yatsurugi, 1. Kohno, and T. Nozaki: ibid., p.
104.
Y. Yatsurugi, O. Kuboi, M. Hashimoto, H. Nagai, M.
Aratani, M. Yanokura, I. Kohno, and T. Nozaki: Appl.
Phys. Lett., 44, 246 (1984).

132
RIKEN Accel. Progr. Rep. 18 (1984)

111-3-7.

Measurement of the Impurity Hydrogen Concentrations on
the Surfaces of the Neutron Bottle
Y. Kawabata, M. Utsuro, S. Okamoto,* S. Hayashi, and T. Nozaki

Neutrons having energies below about 100 neV
are called "ultracold neutrons (DCN)." Owing tosuch low energies, their motion is affected easily by
the gravity, magnetic fields, or nuclear potentials
in condensed materials. Therefore D CN provide
much unique information. 1)-6)
DCN having energies lower than the sum of
nuclear and magnetic potentials are reflected at any
incident angle. Nickel and beryllium, which havethe total potential of 2.7 or 2.0 X 10- 7 and 2.5 X 10- 7
eV, respectively, are regarded as being usefulmaterials for long-time confinement of DCN.
Although many neutron bottle experiments havebeen carried out, all of the results show the confinement times far shorter than the theoreticalvalues. The reason for this is supposed to be thepresence of surface hydrogens. Despite the successful measurements of the quantity of the hydrogen on some neutron bottle surfaces,7) all trials
to remove the hydrogen have failed. 8) In the present
study, therefore, we repeated the measurement of
the surface hydrogen with some neutron bottlematerials and tried another approach to remove itfrom the evaporated Ni layer.
The Rutherford Forward Scattering (RFS) was(x 102 )
5.12

~

<I:l

used for the measurement of light elements on thesurfaces. 40Ar ions were accelerated to about 50
MeV by the RIKEN linac. The experimental arrangement was similar to that described in a preceding report. As an another method hydrogen concentration profile can also be measured by the resonance reactions of 15N and H. Lanford et al. 7)
have used this method for some neutron bottlematerials. In the present study, deuterium should
also be measured in some case, and the RFS method
was used instead of the nuclear reaction method.
The RFS method employed has the spatial resolution of about 500 A and the accuracy in measuring
total hydrogen amount is better than the resonancemethod.
The spectra obtained with 1,500 A Ni depositedon eu and Al substrates at 1 X 10- 6 Torr are shownin Fig. 1. Hydrogen peaks are seen on the Ni surface
and the Ni-substrate interface. For Ni-Cu mirror
numbers of hydrogen of 1.5 X 1016 and 2.9 x 1016
atoms/cm 2 were found on the surface and the interface, respectively; for Ni-AI, 1.7 X 1016 atoms/cm 2
and 1.2 X 1016 atoms/cm2 on the surface and theinterface, respectively. These values are in good
agreement with the results obtained with the 15N
resonance method. For other neutron bottle materials also, similar values were reported. 7) The

Q)
U..... - co
~

Q)

.....
~

+-' :J
CCf)

10 18

- I

4.48
3.84

• OxygenQ3c~ 3.20HYdrOgen} Ni (600A )-Sio Oxygen
.

A

£.

~
2 2.56
c

10 17

:::l

8 1.92

Ni (1500A) -AI (substrate)
Ilf1.I..(rIJ,II\

1.28
0.64

O·

o

I,l 'JI~~"'1,1<illvnf.rf\"\oI\IJfJll~Ly"\},,,-"~f<t""

J t.~~:,~SUbstrate)
1

256
Channel number

Fig. 1 Rutherford forward spectra for hydrogen distribution
profiles. Right peak shows the surface hydrogen and left theinterface.

*1.. Hydrogen-surface• Hydrogen-interface Ni ( 2 000A) - Si0 2

Research Reactor Institute, Kyoto University.

E
U-.......
VI
E
o
~

10 16

"ll.

"0

...

I

•
I

•

I
10 15 L--L_~--:--J...--:--::'-::--::-::':::-:---="='-:-:'::--;-:;~
10-11 10- 10 10-9 10- 8 10- 1 10- 6 10 5 10 4
Vacuum (torr)

Fig. 2. Hydrogen and oxygen concentrations at various
evaporating pressure.

Y. Kawabata, et al.

10 17 ",...----,-H-:N-,i,...-S=-u-rf,,-a-ce---------.

Eu• Ni - Cu... Ni - AI
• Ni - Pd - Cu
A Ni - oxidized AI

.
~

'-..

::. 10 16
c:
o

t:;.

. ...

~

~c:

...

Q)

g 10 15
o

U
I

10

100

Hour

D : Ni Surface.........

• Ni - Cu.. Ni-AI

E
u

'-..

::. 10 15c:o• Ni - Pd - Cu
Ni - oxidized AI

t:;.

~

I

!

:bc:
Q)

OJ

g 10 14
o

I

u ·

o
10 13 L -_ _ _

J

~

.

_ _ _ _ _ _ _ _--1

10

100

Hour

Fig. 3. Relation between the surface hydrogen (upper) anddeuterium (lower) . concentration and the elapsed time inliquid D20.

hydrogen profiles in deposited Ni layer at various
vacuum pressures are shown in Fig. 2. The amountof hydrogen in the Ni surface layer is hardly affected by the pressure in the region lower than 1 X
10-6 Torr. When the pressure increases further, theregion containing hydrogen extends to deeper.
Although the total hydrogen concentration increases
in this way, the surface hydrogen concentrationis hardly affected. This fact indicates that the surfacehydrogen comes from the residual gas after thedeposit of the layer.
In order to examine the effects of the substrates
on the quantity of the surface hydrogen, Cu, Al
and quartz substrates deposited with Ni are compared. As the inner surfaces of neutron bottle must
be a high-quality mirror for multiple reflectionsof DCN, they were polished optical-flatly. Theirsurface roughness for depth was less than 200 A.

133

The quantity of hydrogen on the interface was affected considerably by the surface condition of
the substrate. For instance, the presence of oxygen
layer on the Al substrate causes the increase ofhydrogen. Palladium, as a hydrogen reservoir, wasdeposited between the substrate and the Ni layer.
Quartz was also used for the substrate and assured
to be clean for hydrogen. However, the quantity ofthe surface hydrogen with 2,000 A Ni layer was
independent of hydrogen concentrations in thesubstrates.
The Ni-deposited samples were immersed inliquid D 2 0 to examine the possibility of the replacement of H with D. The quantities of Hand D were
measured as a function of the immersion time.
Results shown in Fig. 3 indicate that permeationof D obviously takes place from the surface, though
the surface hydrogen concentration seems to beinvariant. Thus, it is expected that the replaced
D on a very thin surface layer may be reexchanged
with H in the atmosphere within a very short time.
As an another explanation, the presence of D on thesurface cannot prevent possible hydrogen absorption. Therefore, these results indicate the difficultyof removing the hydrogen by the exchange withD.
One of the attractive materials for a neutron
bottle is Be, since it has a high nuclear potential.
The surface hydrogen in Be was also measured
and found to be 2.1 X 1016 atoms/cm 2 • It is the sameorder as the other materials.
References
1)

A. Steyerl: in Springer Tracts in Modern Physics, vol.
80, Springer, Berlin p. 57 (1977).
2) R. Golub and J. M. Pendleburg: Rep. Prog. Phys. Lett.,
42, 439 (1979).
3) M. Utsuro and Y. Kawabata: Physica, 120B, 118(1983).
4) A. Steyerl, B. Gmal, K.-A. Steinhauser, N. Achiwa, andD. Richter: Z. Phys., 255, 146 (1972).
5) M. Utsuro: ]. Phys., C3, 277 (1984).
6) R. Golub and J. M. Pendleberg: Phys. Lett., 50A, 177(1974).
7) W. A. Lanford and R. Golub: Phys. Rev. Lett., 39,
1509 (1977).
8) P. H. La Marche, W. A. Lanford, and R. Golub: Nucl.
Instrum. Methods, 189, 533 (1981).

134
RIKEN Accel. Progr. Rep. 18 (1984)

111-3-8.

High Sensitivity Analysis of Deuterium in Solids by
15N-lnduced Nuclear Reactions
S. Hayashi, H. Nagai, M. Aratani, T. Nozaki, M. Yanokura,
I. Kohno, O. Kuboi, and Y. Yatsurugi

We have already reported 1) on not only a method
for measuring the depth profile of hydrogen but a
new method for determining the contents of deuterium with such a high sensitivity as 1018 at·cm- 3
in solids by means of 15N -induced nuclear reactions.
Further, we have developed and applied this new
method to measure deuterium contents in various
materials. Surfaces of most materials, however, arealways covered with hydrogen, which is derived
by adsorbing water or hydrocarbons in an atmosphere. The adsorbed hydrogen often interfereswith precise measurement of hydrogen in thebulk. In order to study hydrogen in solids, the useof deuterium as an activable tracer is regarded as
widely profitable. This method of high sensitivity
quantitative analysis of deuterium by 15N-induced

10 J
1.02

nuclear reactions was discovered during the studyof depth profiling of hydrogen in some materials byusing the resonance nuclear reaction, 1H(15N, ar)12C (Er=4.44 MeV). The method of determining
deuterium is based on other nuclear reactions,
2H(15N, pr)16N and 2H(15N, nr) 16 0. No precise
cross sections of the nuclear reactions have beenreported by now. They must not be resonancereactions, and therefore they can be applied not
to depth profiling but to quantitative analysis of
deuterium.
Incident beam of 15N2+ ions was supplied fromthe RIKEN heavy-ion linac, and led to the Al
course. Experimental arrangement is almost thesame as was shown in the previous report. 1) A pairof BGO (Bi4Ge3012) scintillators has been used for

~
~

t-

o

oj

r'P
~

~ 0

\0

.....
r-i
0·77

~

~ .....
~

0.90

~
ex>

~

~

\0

0

:=l

\0

M

0.64
....J

w
:z:
:z:
..:
:r:
u
"(f)

~ .....CJ
~

oj

~

~ ~
N

N

0.51

~

~

r-: r-:
0

:=l

0

\0
~

f-

:z:

:J
0

0. 38

u

0 .26
a-Si:H (D)0 . 13a-Si:H
512

CHANNEL NUMB ER
Fig. 1. Typical energy spectra for gamma-rays in amorphous silicons induced by
IH(15N, ar)12C, 2H(15N, pr)16N (,8--decay, Tl/2 = 7.13 s), 2H(15N, nr)160, and 2H(15N,
ar)13C. upper, a-Si: H(D); lower, a-Si: H, (s.e.), single escape peak; (d. e.), double
escape peak.

135

S. Hayashi, et aZ.

2 H (15 N ,py)16 N (T~/2=7.13 s)~160
2 H (15 N ,ny)16 o

2 H (15 N ,ay) 13 c

2 H (15 N ,ny)16 0

1

1
~

~

'M

I':
P

+

-+-

....

21J(15 N ,any)12 c

t+

-+- +

-+-

.Q

--7.65~_ _ 3.96

2 H (15 N ,py)16 N

=~:~

~

0.1

+-++

+

...~
+-

---7

0.1

0.1

12

c

11. 31

'"
r--

7.12

:rrr
0

CJ\

15

c

I

6.05

3.09
26%

:

~..;
~
13

U~

68%

N

6.92
6.13

~,..:

.

J1j""::::'"

6.36

Energy (MeV)

Fig. 2. Excitation functions of 2H(15N, nr) 16 0 (upper) and2H(15N, pr)16N(Iower). Solid curve was derived from thereaction of 15N(d, p)16N reported by Bostron et al. 2 )gamma-ray detection. We have partially improved
the gamma-ray detection system. The total crosssections of these two reactions have tendencies toincrease with the l5N energy over a wide range.
However, neutrons with continuous energies are
emitted by the process of l5N ~ 14N +n, whenthe energy of 15N exceeds '""-' 11 MeV. These fastneutrons, which also give scintillation in the BGO
crystal, interfere seriously with gamma-ray detection. We successfully adopted an ordinary pulseshape discrimination technique for n-r separation.
In order to monitor the incident beam, a thin carbon
foil ('""-' 10 pg/cm 2 ) was used, and scattered particles
from the foil were detected by using silicon surface
barrier detector (SSD).
First, we measured the excitation functions of
total cross sections for two nuclear reactions, 2H(15N,pr)16N and 2H(15N, nr)160. In the first step,
we obtained the sum of the two total cross sections
by measuring the intensities of high energy gammarays (Er=6.13 and 7.12 MeV) emitted from thetwo processes in a thin target of deuterium-enrichedamorphous silicon a-Si: H(D) (2,280 A). Figure 1
shows typical energy spectra of gamma-rays induced
by l5N ions (upper, a-Si:H(D); lower, a-Si:H).
In the second step, only the cross section of 2H(15N, pr )16N reaction was evaluated by measuring
the intensities of such gamma-rays using leastsquares analysis of t~e decay curve in the multichannel scaling measurement of l6N (Tl/2=7.13s)
during beam off. The excitation functions from 5 to

16

0

4.14

Fig. 3. Energy levels of the 12C, 13C, 160, and 16N nucleI
for reference to identify the origins of the gamma-rays
emitted from four nuclear reactions: 2H(15N, pr)16N, 2H_(15N, nr)160, 2H(15N, ar)13C, and 2H(15N, anr)12C.

16 MeV are shown in Fig. 2. A solid curve overlapping our experimental data of the cross section
for 2H(15N, pr )16N reaction is derived from otherexperimental results of l5N( d, p )16N reaction reported by Bostron et al. 2) for reference, in which a
projectile and target were interchanged. An ordinate
in Fig. 2 is a total cross section in arbitrary units.
Further experiments for determining absolutevalues of the total cross sections are now in progress.
Secondly, we applied this method to the determination of deuterium contents in various materials.
As is shown in Fig. 1, several other gamma-ray
peaks are observed in addition to 4.44, 6.13, and7.12 MeV peaks. All these peaks are shown tooriginate from following three nuclear reactions,
2H(15N, pr)16N, 2H(15N, nr)160, and 2H(15N, ar)l3C. To identify the origin of gamma-rays, we
illustrate the energy levels of the l2C, l3C, 160, andl6N nuclei in Fig. 3. Among these peaks, 6.13 and7.12 MeV peaks are very suitable for quantitative
analysis of deuterium, because there are no interference peaks in the energy region higher than thehydrogen-originated 4.44 MeV peak. Total amountof deuterium in various materials was determined136

S. Hayashi, et al.

Table 1. Deuterium contents measured by 15N_NRA
and Rutherford recoil methods.
(at'cm- 3 unit)
Sample15N-NRA

Rutherford

a-Si: H (D) (730A)
a-Si: H (D) (1330A)
SIPOS
SiNa: (in D20, 127°C)
c-Si (in D2, 800°C)
c-Si (in D2, 1100°C)(2.23 ±0.13) X 10 21(1.35 ±0.07) X 10 21(4.97±0.02) X 10 20(2.17 ±0.04) X 1019
(7.32±0.22) X 1018
(2.43±0.13) X 1018

2.16 X 10 21
1.35 X 10 21

deuterium is analyzed down to a concentration of a
few times 1018 at.cm- 3 , the most sensitive one indetermining deuterium in solids. Furthermore, twoisotopes, 1Hand 2H, can be measured simultaneously without mutual interference below 14.45
MeV of incident 15N ions. Another reaction channel,
2H(15N, anr)12C, can be opened at that energy,
and produced the same energy gamma-ray (Er=4.44 MeV) as hydrogen originates; see Fig. 3.
Referenceswith reference to a standard material of deuteriumenriched amorphous silicon a-Si: H(D) (1,000 A).
Deuterium contents in some kinds of materials
are summarized in Table 1; in this calculation,
relative cross sections of these reactions were used.
Table 1 also shows experimental data for a-Si: H(D)by the Rutherford recoil method for reference. 3)
We can ensure that by using the present method

1)

2)
3)

S. Hayashi, H. Nagai, M. Aratani, T. Nozaki, M. Yanokura, I. Kohno, 0. Kuboi, and Y. Yatsurugi: RIKEN
Accel. Progr. Rep., 17, 106 (1983).
N. A. Bostron, E. L. Hudspeth, and I. L. Morgan:
Phys. Rev., 105, 1545 (1957).
H. Nagai, M. Aratani, S. Hayashi, T. Nozaki, M. Yanokura, I. Kohno, O. Kuboi, and Y. Yatsurugi: RIKEN
Accel. Progr. Rep., 17, 102 (1983).

137
RIKEN Accel. Progr. Rep. 18 (1984)

111-3-9.

Thermoluminescence from the Ar-bombarded Silica
M. Aratani, T. Hashimoto, S. Hayashi, M. Yanokura,
H. Nagai, I. Kohno, and T. Nozaki

Observation has been made on the thermoluminescence from Ar-bombarded silica. Silica samples
used were quartz plates and silicon oxide films(SiOx , x=2, 0·26 ,urn) prepared by thermal oxidation. Bombardment was performed by using a I mscattering chamber installed in a course, A-I, of the
Linac under the various conditions listed inTable 1. The samples were set slant by an angle of
30° to an incident beam. Si ions forward recoiled
by Ar ions were used for monitoring the incident
Ar-ion beam. Si ions were detected with a siliconsurface-barrier detector situated at the angle of 37°
to the indident Ar beam. Detailed experimental
arrangement was previously reported. 1)
The samples (9 mm X 19 mm) Ar-bombarded in
the dark vacuum chamber were taken out without
exposure to light, and transferred to a photoncounting thermoluminescence detector. 2) The thermoluminescence of the samples was observed by
Table 1.

raising temperature at a rate of I o/s. A temperaturethermoluminescence curve (glow curve) was recorded from 50° to 400°C. Some of the samples
were examined in the photographic observation
system using extremely high-sensitive color films.
Some results are shown in Figs. I to 3. In eachcase, the glow curve is shown with a backgroundcurve. Dominant peaks are seen in the vicinity of
200°C in Figs. I and 3. In every case, continuumwith ten waves is observed. These glow curves havenever been reported in the literatures published on
the thermoluminescence from geological samples
exposed to the natural-origin radiations, main partwhich is due to the a-particles emitted from thenatural a-emitters. These glow curves are not seenin the thermoluminescence from the silicate samples
bombarded with a He-ion beam, either. 3) Silica isregarded as a main component of natural samples.
Thus, the peak in the vicinity of 200°C and waved

Bombardment conditions in A-1 course of the Linac.

Sample No.

Material

Thickness

Ar
(MeV)

Beam
intensity
(nA)

Time

Forwardrecoil Si

1
2
3
4
5

Si02
Si02
Si02
c-Si
Si02

0.5 mmO.Smm
0.5 mm
0.3 mm0.26 pm

50.7
50.7
50.7
49.6
49.6
52.2
52.2 .

50
15
1
15

5 min
1 hr
1 hr
1 hr

2,004
22,7988,135
147,048
8,078
19,041
3,023

40000

300"0
I:J
0..
I:J
0

20000

I-

:r:
t:J
--1

10000

TEMPERATURE
Fig. 1.

Thermoluminescence of the quartz plate bombarded with Ar ion (15 nA) for 5 min.

Light
outputoverscalenot observed

138

M. Aratani, et aZ.

50000...----------------------------,

10000

50

J00

200

150

250

300

35B

TEMPERATURE
Fig. 2.

Thermoluminescence of the quartz plate bombarded with Ar ion (1 nA) for 1 hr.

400..----------------------------,

390

I-

:::>

c....

1-

:::>
0

200

1I
t:l

-1

/

UP

50

109

150

200

250

300

350

400

TEMPERRTURE
Fig. 3.

Thermoluminescence of the Si02 film on a Si wafer bombarded with Ar ion.

continuum are regarded as characteristic of the Arbombarded silica. The silica samples employed in
the present study were high-pur.ity artificially prepared Si0 2 , and a color image of the plate sample
taken between 50°C and 400°C showed blue luminescence.
Present results suggest that the thermoluminescence study of high-purity material bombarded withheavy ions will be an unexplored field of the optoelectronic application. For example, high-purity
silica and that containing controlled impurities are

subjected to research aiming at heavy-ion dosimetersand standard materials, especially for geological andarchaeological samples.
References
1) H. Nagai, M. Aratani, S. Hayashi, T. Nozaki, M.
Yanokura, I. Kohno, O. Kuboi, and T. Yatsurugi: RIKEN
Accel. Progr. Rep, 17, 102 (1983).
2) T. Hashimoto, K. Kimura, A. Koyanagi, K. Takahashi,
and T. Sotobayashi: Radioisotopes, 32, 525 (1983).
3) J. Kalef-Ezra and Y. S. Horowitz: Int. J. AppZ. Radiat.
Isot., 33, 1085 (1982).

139
RIKEN Accel. Progr. Rep. 18 (1984)

111-3-10.

Adsorption Kinetics of 119Sb(V) Ions onto a-Fe 2 0 3 Surfaces
S. Ambe, T. Okada, and F. Ambe

We are studying the adsorption kinetics of 119Sb(V) onto a-Fe203 surfaces 1) in relation to the study
on chemical states of the adsorbed 119Sb(V) ionsby Mossbauer emission spectroscopy. 2) -4) In thisperiod, we carried out kinetic studies using an
119Sb(V) solution of known Sb concentration andobtained an adsorption rate equation related not
only to the antimony concentration but also to thesurface area of a-Fe 203.
Adsorption of hydrolyzable metal ions on the surfaces of metal oxides from aqueous solutions havebeen extensively studied from equilibrium measurement of the ionic adsorption density and surface
charge density. However, little attention has been
paid to adsorption kinetics yet, because the adsorption of metal ions usually proceeds too fast to beobserved by ordinary methods and is often accompanied with simultaneous precipitation of hydroxides
after neutralization of solutions. We found that theadsorption of no-carrier-added 119Sb(V) ions on
a-Fe203 proceeds at a rate measurable by a conventional tracer method.
When no-carrier-added 119Sb (half-life: 38.0 hr)
was employed as a tracer, it was separated from
119mTe (half-life: 4.68 days) produced by a-particle
irradiation of tin. The procedures of the separationof 119Sb and the final purification of the solution
using activated carbon to remove trace impurities,
Sn(IV) and Te(IV), were described elsewhere. 5)
The resulting 0.25 mol dm- 3 LiCI solution containing 119Sb(V) was used for the adsorption experiments after adjusting pH to 4.0. Concentration of
antimony in the solution was found to be 1.1 X 10-8
mol dm- 3 by neutron activation analysis after preconcentration of Sb(V) on a-Fe203. Forty five mg
of a-Fe 203 was added to 60 cm3 of the 119Sb(V)solutions at 30, 40, 50, and 60°C. Adsorption experiments were also carried out with various
amounts of a-Fe203 at 50°C. The suspension was
shaken in an 8-shape mode with a shaker. An aliquotof the suspension was taken everyone minute fordetermination of the fraction of 119Sb adsorbed.
After removal of a-Fe203 particles in the aliquot byfiltration using a glass fiber paper, 23.8 keY r-rays
and Sn K X-rays of 119Sb in each filtrate werecounted with an NaI scintillation counter.
Let us suppose that the rate of the adsorption
reaction

Sb (V)+(a-Fe203 surface) ~ product
(a-x)
(b-y)
is experessed by(1)

dx/dt=h(a-x)n (b-y)mwhere a is the initial concentration of antimony (V)ions in the solutions, and b .is that of the free surface
area of a-Fe203. The reverse reaction, that is,the desorption of 119Sb(V) from the 119Sb-a-Fe203
was found to be negligible. The surface area of
a-Fe203 employed (45 mg) is considered to be inlarge excess for the adsorption of Sb(V) ions, because the BET surface area of 45 mg of the sample
used in the present study is 1.2 m 2 and monolyer
adsorption of 6.6 X 10- 10 mol of Sb (Sb in 60 ml of
the tracer solution) requires 5.6 X 10-5 m 2. Thus,y can be neglected against band Eqn. (1) can be
simplified as
dx/dt=h' (a-x)n(2)

h' =hbm, i.e., logh' =mlogb+ logh

(3)

The free surface area b is proportional to the quantityof a-Fe203 and can be expressed in the unit of mol
dm- 3 for convenience. By analyzing the adsorption
data obtained at 30, 40, 50, and 60°C according to
Eqn. (2) in a differential and integral forms, theorder of the reaction n was found to be 2. Figure 1
shows the results of analysis by the integration
method. The relation between l/(a-x) and t exhibited a good linearity, giving the apparent rate
constant k' from the slope.
The value of m can be obtained from the slope of a(x 10 8 )
6

i

5

"0

E

E

~

i

~
I
~

4

3
2

Time

Fig. 1.

(min)

Relation of l/(a-x) vs. time.

140

S. Ambe, et aZ.

adsorption is, therefore, expressed as:
dxfdt= k(a-x)2b 2
k=1.1 X 1012 dm9mol- 3min -1 at 50°C
From the finding that n is equal to 2, it is likelythat two Sb(V) ions or dimers are involved in theadsorption reaction. Similar experiments on otheroxides having the corundum- and spinel-type crystal
structures are also being carried out.
References
6L-______~~------~---J-3.0

log (b/ mol dm - 3 )Fig. 2.

Relation of log k' vs. log b.

log k' vs. log b plot and the intercept of log k' gives
the rate constant k. From the rate constants k' obtained at 50°C with various quantities of a-Fe203, m
was found to be 2 as shown in Fig. 2. The rate of

1)

2)
3)
4)
5)

S. Ambe, F. Ambe, and T. Okada: RlKEN Accel. Progr.
Rep., 15, 114 (1981).
T. Okada, S. Ambe, F. Ambe, and H. Sekizawa:]. Phys.
Chem., 86, 4726 (1982).
F. Ambe, S. Ambe, T. Okada, and H. Sekizawa: RIKEN
Accel. Progr. Rep., 17, 109 (1983).
F. Ambe, S. Ambe, T. Okada, and H . Sekizawa: p.141
in this report.
S. Ambe: ]. Radioanal. Nucl. Chem., Articles, 81, 77(1984).

141

RIKEN Acce1. Progr. Rep. 18 (1984)

In Situ Emission Mossbauer Study of 119Sb5+ (~119Sn4+) Ions at
a-Fe 2 0 3 -Aqueous Solution Interfaces

111-3-11.

F. Ambe, S. Ambe, T. Okada, and H. Sekizawa

We have been studying the chemical states ofcyclotron-produced 119Sb5+ ions adsorbed on magnetic oxide-surfaces by emission Mossbauer measurement of supertransferred hyperfine (STHF)
fields on 119S n 4+ nuclei arising from 119Sb5+. 1 ) In
the last report,2) we showed that in situ Mossbauer
observation is feasible with 119Sb5+ ( ~ 119Sn 4+) at
the interfaces between oxide particles and an
aqueous solution. Here, the effects of heating on the

99

after
heating,~t 98°C,.le/'"
It

~

.iii
c

2

II

'(i)

~

pH 7.9pH 4.4

.'

Q)

>

[A2J

pH 4.4.S~

pH 6.6

I' '" I,.-P\

'

[8lJ

99

[AlJ

..........

.....

100 ...... :t \ 4\'suspension of a-Fe203 particles with adsorbed
119Sb5+ ions are reported. Results on a dried
CoFe204-119Sb5+ sample are described In a
separate report of ,t his volume. 3)
The procedure of separating no-carrier-added
119Sb from a-irradiated tin target was described
elsewhere. 4) The experimental setup of the in situ
Mossbauer measurement was given in Fig. 1 ofRef. 2. The a-Fe203-119Sb5+-aqueous solution
system was heated in a water bath with a glass reflux.,

100 .~?
•

99.......

II·

I,

•

[~2'J :':::'\'

after • '. .:........ . ... : ~heating•••. ~.
, .:",

pH 4.3[82J

pH 4.3[Cl]

pH 2.6[C2J

pH 2.6at 98°C

100~~••:~...."".
[Cl].''',.

99

-15

'.'

pH 2.6.

-10 -5

0

5

10

15

Ao A~'

Relative velocity (mm/s vs BaSn03)

Fig. 1. Preheating effects of the sample suspensions at 98°C
for 30 min upon the in situ emission Mossbauer spectra of
119Sn arising from 119Sb5 + at the a-Fe203-0.2S mol dm- 3
LiCI solution interfaces (measurement at room temperature).
The curves are composed from the results of HesseRUbartsch analysis given in Fig. 2.

a

A~ A'i

8

50
100
150
Hyperfine magnetic field (kOe)

Fig. 2. Distribution of the STHF fields on 119Sn 4+ nuclei
obtained by the Hesse-Riibartsch analysis of the spectra
shown in Fig. 1.

F. Ambe, et al.

cooler connected to the top of the Teflon sample
vessel.
Figure 1 compares the Mossbauer emission
spectra of the a-Fe20i- 119 Sb5+-0.25 mol dm- 3
LiCI solution system at three different . p.H before«A1)- (C1)) or after heating at 98°C for 30 min«A2)-(C2)). The experiment was made on the aFe20a sample prefired at 900°C. As in the "as obtained" a-Fe20a sample reported previously,2) 119Sn
ions arising from 119Sb5+ at the interfaces are exclusively of the tetravalent state and the line width oftheir emission increases with decrease in pH of theaqueous phase. A large change in pH was observed
after heating the system of pH 6.6, since no buffer
was employed in the aqueous phase. At every pH
value studied, the emission spectra show considerable broadening or even immature splitting to a
sextet after heating. The observation suggests incorporation of more 119Sb5+ ions by heating into
the surface metal-ion sites having significant STHF
interaction with the antiferromagnetically ordered
57Fe3 + ions of the substrate. Further heating up to
100 min brought about no further appreciablechange in the spectra.
The STHF field distributions obtained by the
Hesse-Riibartsch analysis5) of the spectra in Fig. 1
are given in Fig. 2. At the bottom of Fig. 2 is shown
the STHF magnetic field on 119Sn4+ nuclei in thebulk of a-Fe20a at room temperature (122 kOe)6) as
well as the fields for 119Sn4+ at the surface metalsites, Au o, AdO, Au l , and Adl (see Fig. 10 of Ref. 1);
calculated on the assumption that the STHF field is
proportional to the algebraic sum of the reduced
magnetization of the Fe 3+ ions interacting withthem. The values of the reduced magnetization forsurface F e3 + ions of a- F e203 were taken from ourprevious work. 7)

As can be seen from Fig. 2, a considerable amountof 119Sb5+ ions are present in the bulk (the secondand deeper layers) after heating at pH 4.3 (B2)
and 2.6 (C2). In the dried a-Fe20a-119Sb5+ sample
reported previously, no appreciable diffusion of
the surface 119Sb5+ ions into the second or deeper
layers was observed on heating the sample at 200°C
for 2 hr (Fig. 3 of Ref. 1). Therefore, the change ofthe field distribution observed in the present in situ
experiment is not likely due to diffusion of surface
119Sb5+ ions into the second or deeper layers. Moreover, the finding that the change saturates on 30 min
heating suggests a different mechanism. We consider that a certain chemical rearrangement of ·thesurfaces occurs when the a- F e20a particles are incontact with the aqueous phase at 98°C. Namely,
some F e3 + ions are released from the surfaces of
a-Fe20a particles and are again attached to themso as to incorporate a part of the 119Sb5+ ions into
the second or deeper layers. Since the change does
not proceed further after 30 min, it is concluded
that the rearrangement is limited only to a few
layers of the surfaces and the 119Sb5+ ions are distributed among them.
References
1)
2)
3)
4)
5)
6)
7)

T. Okada, S. Ambe, F. Ambe, and H. Sekizawa:]. Phys.
Chern., 86, 4726 (1982).
F. Amhe, S. Ambe, T. Okada, and H. Sekizawa: RIKEN
Accel. Progr. Rep., 17, 109 (1983).
T. Okada, F. Ambe, S. Ambe, and H. Sekizawa: p. 90
in this report.
S. Ambe: J. Radioanal. Nucl. Chern., Articles, 81, 77(1984).
J. Hesse and A. Rlibartsch:]. Phys. E, 7, 526 (1974).
Unpublished data.
F. Ambe, T. Okada, S. Ambe, and H. Sekizawa: J. Phys.
Chern., 88, 3015 (1984).

143
RIKEN Accel. Progr. Rep. 18 (1984)

111-3-12.

Correlation between Angular Anisotropy of Fission Fragment andIts Mass in System of p + 232Th
Y. Hamajima,* K. Sueki, M. Magara,** H~ Nakahara, and I. Kohno

Moller and Nilsson l ) suggested that there might be
two kinds of saddle configurations, one with reflection symmetry with respect to the axis perpendicular to the nuclear symmetry axis and the otherwith reflection asymmetry, and that the fission
barrier height for the symmetric saddle would be afew MeV higher than the one for the asymmetricsaddle. They also suggested that the final mass
division mode could be related closely to these twokinds of saddle point configurations. It there truly
exist two kinds of saddles and if they control the
final mass division mode, fragment mass dependenceof angular anisotropies should be observable in a
fission system where an appreciable difference inanisotropies is expected from Bohr's channel
theory2) for the fragments that have passed throughdifferent kinds of saddles. In 1982, Kudo et ai. 3 )reported for the 15 MeV p+232Th system that correlation between the angular anisotropy and thefragment mass could well be reproduced on theabove assumption.
In the present study energy dependence of thecorrelation between the angular distribution offission fragments and its mass is examined further
with the system of 13 and 15 MeV p+232Th.

1.00

TH - 232 + P [15.0 MeV]

. . '. ". ;f-Y

0.60

"0

20.0 - 159.61 Deg.

\. . . .>(.t0.20~ 0.00The Th target (about 0.1 mg/cm 2 in thickness)prepared by vacuume evaporatio~ onto a carbon
film was bombarded with 13 MeV and 15 MeV
proton beams from the cyclotron. The coincident
complementary fragments were detected with two
surface barrier detectors. Details of experimental
setup and the analysis have been given previously.4)
The mass yield curve (small dots) observed forthe 15 MeV p+232Th system at 20° is compared withthat for the 14.8 MeV p+232Th system reported by
Kudo et ai. 5 ) (closed circles) in Fig. 1. The curve
obtained in the present study is in good agreementwith the result by Kudo et ai. who used a radiochemical technique. Mass dependent angular anisotropies (W(00)/W(900)) for the 13 MeV (opencircles) and 15 MeV (closed circles) p + 232Th system
are shown in Fig. 2. In the 15 MeV p+232Th
system the angular anisotropies of symmetricallydivided fission fragments were found different fromthose of asymmetrically divided ones. Theroretically predicted angular anisotropies in the 15 MeV
p+232Th are 1.06 for symmetric fission and 1.3 forasymmetric one. They have been calculated fromthe expression given by Vandenbosch and Huizenga6) by taking into account the contribution ofmultiple change fissions predicted from the statistical model that assumes the existence of two different saddle points. Experimental data are in good
agreement with theoretical values.
For the 13 MeV p + 232Th system, theoretically1
1.4• 15 MeV

-0.20

~ 1.3

-0.60

~
::::::: 1.2
b
~ 1.1

~

-1~0

o 13MeV} P+Th}t

1.0 1.0

1.1

1

I

I

2

2

2

1.2 1.3 1.4 1.5Mass ratio (MH/ML)

1.6

1.7

1

I
2

!

2

I

60.00 80.00 100.00 120.00 140.00 160.00 180.00
Fragment mass (amu)Fig. 1. Mass-yield curve of the proton induced fission of
232Th. Small dots for 15 MeV p (this work) and closed
circles for 14.8 MeV p (Kudo et al.).

* Faculty of Science, Kanazawa University.
** Faculty of Science, Tokyo Metropolitan University.

Fig. 2. Mass dependent angular anisotropies for the 13 MeV(open circles) and 15 MeV (closed circles) p + 232Th systems.
Theoretically predicted anguiar anisotropies for symmetricfission are 1.06 for both 13 and 15 MeV and those forasymmetric fission are 1.06 and 1.30 for 13 and 15 MeV,
respectively.

144

Y. Hamajima, et al.

predicted anisotropies are 1.06 for both symmetricand asymmetric fission. Although the anisotropiesof this study are somewhat higher than the theoretical ones, they are consistent with the theory which
predicts that the anisotropy for symmetric products
would not be much different from that for asymmetric ones.
The agreement between the theoretical prediction and the observed anisotropies suggests that
there are two kinds of saddle points with different
barrier heights and that the final mode of mass
division is determined essentially at the saddle
points in the process of nuclear deformation towardfission.
References
1)
2)
3)
4)
5)
6)

P. Moller and S. G. Nilsson: Phys. Lett. B, 31, 283(1970).
A. Bohr: Proc. 1st UN Conf. on the Peaceful Uses ofAtomic Energy (II), 911 and 151 (1955).
H. Kudo, Y. Nagame, H. Nakahara, K. Miyano, and I.
Kohno: Phys. Rev. C, 25, 909 (1982).
Y. Hamajima, K. Sueki, H. Nakahara, and I. Kohno:
RlKEN Accel. Prog. Rep., 17, 29 (1983).
H. Kudo, H. Muramatsu, H. Nakahara, K. Miyano, andI. Kohno: Phys. Rev. C, 25, 3011 (1982).
R. Vandenbosch and J. R. Huizenga: "Nuclear Fission,"
Academic, New York (1973).

145

RIKEN Accel. Pro gr. Rep. 18 (1984)

111-4.

Radiation Chemistry and Radiation B'iology

1.

Electron Scavenger Effects on the Fluorescence Induced by 'Single High-LET Particle
Y. Ito,* Y. Aoki,* T. Azuma,* Y. Katsumura,* Y. Tabata,* and K. Kimura

The present study on fluorescence induced byhigh-LET ions is an extension of our previous comparative studies for electron scavenger effects on
positronium formation, muonium formation, andr-induced fluorescence. A single-particle hitting andsingle-photon counting technique, whose block
diagram is shown in Fig. 1, was used for measurement of fast fluorescence decay. The 24 MeV aparticles, after passing through a thin film of plastic
scintillator and a thin window of titanium, wasstopped in the cell which contained a solution of
cyclohexane with both scintillator (PPO: 2, 5diphenyloxazole) and electron scavenger. Twophotomultipliers (PM, HTV 1828-01) were provided: PM 1 gave a start pulse by counting aphoton from the scintillator film; PM 2 attachedto the window of the sample cell gave a stop
pulse by counting of fluorescence of the sample.
The time between the start and the stop signal
was analyzed by a time-to-amplitude converter
and a 1K channel pulse height analyzer.
In order to satisfy the conditions of a singleparticle hitting radiolysis, the current of a-particles
was extremely reduced so that the rate of the startpulse was less than 10- 3 times of the cycrotron
RF-frequency (7 MHz), This may be supportedby the observed excellent time resolution, ca. 1.5

ns at FWHM, which was estimated from the risetime of the fluorescence time profile. This resolution
time may, however, be shortened somewhat, probably by improvement of such as efficient photon
collection by PM 1, since that for r-induced fluorescence obtained using by the same electronic circuits
was 1.0 ns.
A sample solution containing PPO as a scintillator(10 mM) and C2H5Br as electron scavenger (10- 4
to 1 mM), was bubbled with He gas and pumped
into the cell by using a continuous flow-system.
Benzene was also used as the solvent for comparison.
Figure 2 compares the time profiles of the r- anda-induced fluorescence in 10 mM PPO solutions in
cyclohexane and benzene. The fast components of
the lifetimes of excited PPO* on both irradiations
were estimated from Fig. 2 (a) and 2 (b) by using a
convolution technique. The obtained lifetime for
r-irradiation was close to an intrinsic one of excited
PPO* (1.6 ns), while the lifetime for a-irradiation
was much shorter, 1.2 ns. For the fluorescence inbenzene, on the other hand, the lifetime of the fastcomponent was not much different between rand a-irradiation.
The fluorescence intensity was more intense inbenzene than in cyclohexane: the intensity ratio,

He ionfrom cyclo.

Fig. 1. Block diagram for fluorescence measurement using the single-particle
and single-photon counting technique.

* Faculty of Engineering, The University of Tokyo.

146

Y. Ito, et al.

Q):5

100%v---~

80 %
60%

b

"in
c:

40 %

Q)

C

20 %

Q)

o

c:

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

Q)

oC/)

10-"1 10- 3 10- 2 10- 1 1
Concentration of Scavenger [(C 2 HsBr) / mM]

eo

::l

u:

o

5

10
Time (ns)15

20

Fig. 2 (a) Time resolved profile of fluorescence of PPO in
C-hexane.

Fig. 3. Relative intensity of fluorescence as a function ofscavenger (C2HsBr) concentration.
- , r-irradiation; 0, a-irradiation.

scavenging reactions between PPO and C2H sBr.
A modified experimental Warman-Asmus-Schuler(WAS) equation (Eqn. (1)) was found to express
the experimental results failry well l ) :

IF
vaoc;
1+ vaoc;
IFo = va oCo+aC3 1+va oC o+aC

b

"in
c:

2c:

Q)

o

c:

Q)

oC/)

eo

::l

u:

o

5

10
Time (ns)15

20

Fig. 2 (b) Time resolved profile of fluorescence of PPO in
benzene.

I F (10 mM PPO in benzene)/IF (10 mM PPO in
cyclohexane), was 30 for a-irradiation in contrast
to the ratio of 2 for r-irradiation.
The effect of the electron scavenger, C2HSBr, on
the intensity of the a-induced fluorescence was measured and compared with the results of r-induced
fluorescence. As in r-induced fluorescence,l) C 2H sBr
did not influence the lifetime of the emission but
simply reduced the intensity. A plot of fluorescenceintensity vs. scavenger concentration is shown in
Fig. 3. In the case of the r-induced fluorescence in
cyclohexane solution, the effect of C 2H sBr can be
explained in terms of competition in electron(1)

where I F O and IF are the fluorescence intensities in
10 mM PPO solution in cyclohexane without andwith the scavenger, respectively; al(=15 M- l)
and a2 (= 7.2 M- l) are the reactivity parametersof PPO and C2H5Br: Cl and C2 are their concentrations. The solid line in Fig. 3 represents the results
for r-ray induced fluorescence (or Eqn. (1)). The
experimental plot for the a-induced fluorescencedeviates from this line only slightly.
The WAS-type equation is believed to be related
to the inhomogeneous nature of the distribution
between geminate ion pairs in r-irradiated cyclohexane. The similarity in the electron scavenger
effects between r- and a-induced fluorescencemight mean that the local structure of the spur
which is responsible for the formation of the excited
PPO* is not much different for both r-ray and aparticle.
Further experiments using heavy ions with muchlarger LET are under way.
Reference
1)

Y. Ito, Y. Katsumura, T. Azuma, and Y. Tabata:}. Phys.
Chern., 84, 1921 (1984).

147

RIKEN Accel. Progr. Rep. 18 (1984)

111-4-2.

Inactivation of Bacterial Spores by a Single Heavy Ion (II)T. Takahashi, F. Yatagai, T. Katayama, A. Yunoki,
Y. H. Kang, D. S. Kim, I. Kaneko, and S. Okada

Experiments have been carried out for a better
understanding of the mechanism of inactivation of
B. subtilis spores by heavy-ion and alpha-particle
irradiation. Measurements were made on the fractions of dead spores hit by ions whose paths were
within about 0.5 p.m from the center of the spore.
The spores were fixed with 10% aqueous polyvinyl
alcohol solution on a CR-39 plastic detector and theoutgrowth for each spore was photographed after
irradiation. 1) The plastic detector was etched for120-140 min in case of alpha-particle irradiation.
The etching condition for heavy ions was the sameas previously reported. 1) Preliminary results showthat the fraction of dead'spores hit by a single alphaparticle of 0.8-1.7 MeV is 20-300/0' by an Ar-ion
of energy .......,35 MeV is about 300/0, and by a Xe
~ 0.6
oBombaraded by Ar ion (about 35MeV)

0.
VI-g 0.4
Q)

-0

'0

§ 0.2

=~=~ -controls

:.;:;

u
c
ro

~

°0~~~~--7-~~~--~~--------Distance between the center of spore core
and the center of etch pit (tim )Fig. 1. Fraction of dead spores as a function of distance fromthe center of the spore core to the center of the etch pit.
VisibleUVTable 1. Relative yield of luminescence from CR-39 andcellulose nitrate (CN) as compared with BaF2 scintillator for
UV photons and Pilot U scintillator for photons of visible
wave lengths.

CR-39
CN
BaF2
Pilot U

VisibleUltraviolet

to- 3
to- 3

10- 4
10- 4
1

ion of energy 20-60 MeV is about 500/0' In Fig. 1
is shown the fraction of dead spores as a function ofradial distance from the track of an Ar-ion. The
result obtained for Ar is in accordance qualitatively
with those obtained by Facius et al. 2) and Schafer
et al. 3) who claimed "a low inactivation probability
at small impact parameters." As for the "longrange effect" of heavy ions, 1) - 4) our preliminary
results are favorable (Fig. 1), but the number ofspores tested is not sufficient to obtain a decisive
conclusion. Further improvement of viability ofthe spores and more precise marking on the plastic
detector are necessary.
A possibility of UV emission by impinging ions
upon a plastic detector (CR-39 or cellulose nitrate)
has been examined by using 210PO alpha-source,
because UV photons may inactivate spore·s. Figure 2
shows a device which is capable of measuring lightyields, and Table 1 gives present results. Since theyields of ultraviolet light emitted from the plastic
detectors by an alpha-particle are less than 10-4 tothose from BaF2 scintillator, the possibility ofinactivation of the spores due to UV photons is
ruled out.
References
1)

2)

3)
4)
Fig. 2.

A device for the measurement of light yield.

T. Takahashi, F. Yatagai, T. Katayama, Y. H. Kang,
S. Tamada, 1. Kaneko, and S. Okada: RIKEN Accel.
Progr. Rep., 17, 116 (1983).
R. Facius, M. Schafer., and H. Bucker: Adv. Space Res.,3, 85 (1983).
M. Schafer, R. Facius, and H. Bucker: Proc. 8th Symp.
Microdosimetry, p. 755 (1983).
T. Takahashi, F. Yatagai, and A. Matsuyama: Sci. Papers
I. P. C. R., 74, 51 (1980).

148

RIKEN Accel. Progr. Rep. 18 (1984)

111-4-3.

DNA Damage in Cultured Human Tumor Cells after
Nitrogen-Ion Irradiation
I. Kaneko, K. Eguchi, T. Takahashi, T. Inada, and K. Nakano

Heavy-ion irradiation shows marked biologicaleffect compared to that of r- or X-rays. In order toelucidate the cause of this enhanced cell inactivationand characterize the effect of o-rays on DNA lesions,
induction and repair kinetics of DNA lesions after
exposure to N -ions were studied in comparison to
those after irradiations with 180 kVp X-rays and60Co r-rays.
Throughout the work, we used HMV-I cultured
cells derived from human melanoma. Cells were
cultured in an F12 medium supplemented with
10% fetal calf serum. Cells in the exponential
phase of growth were irradiated with 95 MeV Nions (LET D X 932 keVIpm) as described previously» Two weeks after irradiation, the number ofcolonies containing more than 50 cells was counted.
This cell line is characterized by a large shoulder
on its dose-survival curves after X-ray or r-ray irradiation as shown in Fig. 1; however, the survival
curve after N-ion irradiation shows small or noshoulder. A value of the relative biological effec-

tiveness (RBE) for N-ions to 180 kVp X-rays at
1% survival was 1.9.
For detection of DNA damage, we used the alkaline elution technique developed by Kohn and his
co-workers.2) This technique is sensitive enough todetect DNA damage induced by radiation at thedoses as small as those used for cancer therapy.
Irradiated cells were lysed on the membrane filter
with 10 ml of Sarkosyl solution consisting of 0.20/0
sodium lauroylasarcosine (Sarkosyl), 2 M-NaCI and0.02 M-EDTA (pH 10.1), and then eluted with analkaline solution (pH 12.1). The DNA fraction
remaining on the filter after the elution (FR)was calculated by subtracting the amount of DNA
in eluted fraction from total DNA initially poured
onto the filter measured microfluorometrically. A
dose-response curve for the production of DNA
lesions by X-rays, r-rays, and N-ions is shown in Fig.
2. The FR which was assayed immediately after Xirradiation decreased exponentially with dose up to
9 Gy. The decrease in log (FR) reflects an increasein the number of DNA lesions such as single strand
breaks and alkali-labile sites. Therefore, Fig. 2
shows that the amount of initial DNA lesions, assayed immediately after X-irradiation, increased

Dose (Gy)

o

3

6

9

c

.~
u

t"II

-= 10-2
01

c
.:;:

1J

a>
"~

"E

n:i

:J
If)

E
(;

o

c:

a:

u.

\
Fig. 1. Survival curves of HMV-I cells after irradiation with
N-ions, 60Co r-rays, and X-rays.
The symbols and error bars represent the means of 3 or 4
samples and standard errors. The curves were drawn byleast-square fitting . • , X-rays; 0, 60Co r-rays; A, N-ions.

0.1 ~----~----~----~----

Fig. 2. Initials DNA lesions in HMV-I cells after irradiation
with N-ions, 60Co r-rays, and X-rays.
Vertical bars represent standard errors for means of 3 or 8
experiments. FR was the fraction of DNA remaining on
filter after elution. Meanings of the symbols are the same as
those in Fig. 1.

I. Kaneko, et al.

Time of" incubation (hr)o
246
1.0 r--_--::::o______- . . . - - . . , . - - - - _ . _ - - ,
~

,

•

l'

1-- - - - - - I: - - -..;. - - - - - :r--

".'I

~

I:

Fig. 3. Repair kinetics of DNA lesions induced by N-ions(6 Gy) and X-rays (6 Gy).
The symbols and vertical bars represent the mean of 3 to 5
experiments and standard errors, respectively. Symbols
without error bars are a single experiment. . , X-rays;
A, N-ions.

with the dose. The amount of DNA lesions producedby r-rays was almost the same level as that by Xrays. The initial DNA lesions induced by N-ionsalso increased with dose up to 6 Gy. The yield of
DNA lesions per unit dose was lower for N-ionsthan that for X-rays and r-rays, and the RBE for
production of DNA lesions was less than unity(about 0.7). This observation at these low doses isin agreement with the results of other investigators. 3 ,4) Figure 3 shows the repair kinetics of
DNA lesions induced by 6 Gy of X-rays or 5 Gyof N -ions. Extents of repair were calculated by

for X-rays.
These results suggest that N -ions induce at least2 types of DNA lesions, repairable and nonrepairable; these are presumably caused by low
and high LET components, respectively. It is
known that the energy deposition of N -ions includes a high LET component in the track core,
and the low LET component by a-ray penumbra
along the track. Takahashi et al. have concluded
that a-rays cause essentially the same effect as thatof r-rays.5) On the other hand, the lesions inducedby the high LET component have been considered
to be non-repairable. 5.6 ) The DNA lesions causedby the low LET component appear to be rapidly
repaired within about 1 hr after irradiation, similar
to those causea. by X-rays. We calculate that about
85% of DNA strand breaks induced by N-ions was
easily rejoined (see Fig. 3). The small RBE valueof the DNA lesion production may be explainedin terms that when cells are irradiated with N-ions
DNA strand breaks are mainly produced by a-rays
and fraction of a-rays in absorbed dose is about 50%
or less. 5) On the other hand, the high RBE value of
N -ions for cell inactivation must be due to higher
yield of non-repairable DNA lesions than thoseby X- or r-rays.
References1)2)

log (FRro/FRrt)/log (FRro/FRc ),where subscripts ro, rt, and c stand for FR's forcells just irradiated, for cells irradiated and thenincubated at 37°C, and for control cells, respectively.
It was shown that the repair kinetics for N -ions
is similar to that for X-rays in an early incubation
period, but residual DNA lesions remained at ahigher level after a 6 hr incubation for N -ions than

149

3)
4)
5)
6)

I. Kaneko, T. Ohno, K. Nakano, and F. Yatagai: IPCR
Cyclotron Progr. Rep., 14, 102 (1980).
K. W. Kohn, L. C. Erickson, R. A. G. Ewig, and C. A.
Friedman: Biochemistry, 15, 4629 (1976).
M. A. Ritter, J. E. Cleaver, and C. A. Tobias: Nature,
266, 653 (1977).
R. Roots, T. C. Yang, L. Craise, E. A. Blakely, and C. A."
Tobias: Radiat. Res., 78, 38 (1979).
T. Takahashi, F. Yatagai, and S. Kitayama: Adv. SpaceRes., 3, 95 (1983).
A. C. Nelson and C. A. Tobias: ibid., p. 195.

150
RIKEN Accel. Progr. Rep. 18 (1984)

111-4-4.

New Broad Emission Bands from Pressurized
Liquid He Impinged by N Ions

K. Kimura, K. Akasu, T. Kuriyama, T. Azuma, and Y. Aoki

At first, the scintillation response of low-temperature, high-density helium gas to N-ion impingement
is summarized, based on detailed analysis of thedependence of scintillation efficiency, dLldE, specificscintillation, dLI dX, and their decay curves on the
stopping power along the path of N ions. 1) Dense
helium gas impinged by ions at 5.2 K and 420
Torr (average interatomic distance is about 10A) gives emission bands most of which areassignable to excimer emissions. An unknown
triplet centered at 4,585 A, the decay of which
consists of a fast (an apparent lifetime, 32 ns)
and a slow (aftergrow) components, was foundand explained as due to an excimer dimer associatedwith vibrational sidebands which consist of thelowest triplet excimer a 3 and some of long-lived
excimers. In addition, helium presented good
scintillation response to low-energy ions, that is,
the yield of excited states increases rapidly withincreasing stopping power, dE/dX, toward its maximum value, 12 MeV mg- 1 cm 2 as shown in Fig. 1.
This shows not only little quenching of excited statesof helium (atoms, excimers, and excimer dimers)
produced densely in the "primary column" of theions, but also suggests an enhanced yield of excitedstates at dE/dX larger than 6 MeV mg- l cm2 • Such
scintillation response cannot be observed in usual
scintillators (See Fig. 1) and is contrary to what the
scintillation theory predicts. 2 )N -ion impinged liquid helium at 3.9 K showsemission bands quite different from those obtainedby electron irradiation except for several emission
peaks. Broad bands at 5,600, 5,220, 4,980, 4,790,
and 4,490 A are new bands which have not beenreported for electron irradiation (Fig. 2). Of thisspectrum, the bands at 7,280, 7,050, 6,570, and6,390 A can be ascribed to excimer emissions due tothe transition, HI ~ Cl, Jl ~ Cl, Dl ~ Bl, and d 3~ b3 , respectively, although they are broadened
compared with those obtained in gas phase (seeFig. 2). The new broad bands are evidently due
neither to superposition nor to broadening of many
sharp emission peaks ovserved in gas phase, since
there are no gas-phase emission peaks within the
wavelength region covering the broad bands, especially for those centered at 5,600 and 5,220 A, as

shown in Fig. 2. These new broad bands decreasedin their intensities with decreasing pressure: theintensity of the 5,600 A band decreased to 1120 withdecreasing pressure from 5 to 1 atm. By contrast,
the excimer emissions as those observed in gas phaseincrease in their intensities by decreasing pressure:the intensity for the d 3 ~ b3 transition increased to
100 times by decreasing pressure from 5 to 1 atm.
Also, many of the known excimer emissions whichcannot be observed in pressurized liquid helium
became distinct with decreasing pressure to lessthan about 1 atm as shown in Fig. 2.
The new broad emission bands are most likely
due to cluster states of helium excimers, since thebands appeared only under the conditions of highdensity excitation, condensed phase, and impingement of ions of large stopping-power. The broadness of the bands may be caused by loose binding
106r - - - - - - - - - - - - - ,dJ-'b J

~H---/D 1-'B l

JI-+Cl

rY

20
15

...
C

~104
C
o

(5

.I::

0.

X

:3"0

~103
r.

10 3

5

7

10

15

STOPPING POWER(MeV'CM2/mg)

Fig. 1. Total specific scintillation, dL/dX vs. dE/dX forseveral excimers produced in helium gas impinged by 4
MeV/amu N ions at 5.2 K and 420 Torr. Notations of excimers were according to Herzberg's. A curve denoted as Cions is data with a plastic scintillator obtained by Becchetti
et al.: Nucl. Instrum. Methods, 138, 93 (1976).

K. Kimura, et ai.

151

NM

5 .Q X 1 Q37~5~O~~~7~Q~01r~~~6~S~0~~1T~~60~0~~~~__~5f5~~~~~~~
50~O~~~~~~~~~
4~50~~~:<0. 1O~~

4. 0Xl0 3

XO. 10eo

x6. c!~ (l~XO. (01 (10xO. looe

XO. lO CO

XO . 1000

3 . 0X1 C'

A 2.QX 103 I
1. OX10 3

~

II:

t:

XO . 0200

8 . 0X10 3

::::>

..;

700

1. OX 10 4

E
z
B

650
XO . 0200

xli. ono

6 .0 X10 3~

4. 0X10 3en

2 . 0X!03

~

6

C.O

I-

0

21000

;r:

2200D

a...
2. OX! 0 4 F--~~~~' ~4;-5C;'P-0 ,--tfZ (, . 2I.!OC

1w. O~L'O<0 . C2LiO

<0 .

~ '!1

'300

c;:~u

I

I!

1~~

c
(J,Q

lJI!B!~~~~--'-"""'""t~~"""""",""""":~~~.....-.,~-;fn--o--"--=~~~",-~"",,,........Jl~~;..m,,-'-"""J.:...JU~~=="""'22 000

23000

Fig. 2. Emission spectra of pressurized liquid helium impinged by 5 MeV/amu N ions.
A, spectrum at 5 atm and 3.9 K; B, at 1 atm and 3.9 K; C, gas-phase spectrum at 5.2 K
and 420 Torr. Real spectral intensities are obtained by dividing those read from thespectrum by scale factors, if they are given in the upper area of each band.

of excimers which undergo frequent exchange reactions with neighbor excimers in bulks. Lifetimesof the 5,600 and 5,220 A bands were found to be solong that no decay was observed within a pulseinterval of N ions (129 ns). These results clearly
indicate that the long-lived metastable a 3 (1 ms)
is a constitutent of the cluster.
The pressure de pen dense is considered to be correlated with the density of excimers produced.
Liquid helium is known to present large pressure
dependence of density: the density at 4.0 K increases
from 0.129 to 0.142 g cm 3 with increasing pressure
from 1 to 5 atm. The fact that emission intensities ofthese new bands level off at 2 atm for a impingement
seems to support the above explanation for thepressure dependence.
References
1)

K. Kimura, Y. Toda, and M. Imamura: Proc. 7th Int.
Congr. Radiat. Res., (1983), AI-28; K . Kimura, T. Kato,
N. Yamazaki, S. Kubota, and M. Imamura: RIKEN
Accei. Progr. Rep., 17, 113 (1983).
2) R. Voltz, J. Lopes da Silva, G. Laustriat, and A. Coche:
J. Chem. Phys., 45, 3306 (1966); S. P. Ahlen: Rev. Med.
Phys., 52, 121 (1980); F. D. Becchetti, C. E. Thorn,and M. J. Levine: Nucl. Instrum. Methods, 138, 93 (1976).

152
RlKEN Accel. Progr. Rep. 18 (1984)

111-5.

Instrumentation
1.

RIKEN BGOACS System

M. Fukuda, Y. Gono, Y. Ishikawa, M. Sugawara, T. Inamura, M. Ishihara,
T. Nomura, I. Kohno, H. Kamitsubo, J. Kasagi, and T. Murakami
Today, a Ge-detector is most widely used in nuclear spectroscopy for its excellent energy resolution.
But its relatively small peak-to-total ratio is unfavourable to detect weak r-rays when there is alarge background. The improvement of this ratio
can be achieved by using the Anti-Compton Shield(ACS).
Six sets of ACS system which uses BGO (Bi4Ge30 12 ; Bismuth Germanate) crystals are now underconstruction. The advantages to use BGO insteadof NaI(TI) are as follows: (1) A high absorption
coefficient ('"'-'2.5 times of that of NaI(TI» which
reduces the volume of ACS, (2) Manageability
owing to its non-hygroscopic property.
The cross-sectional view of RIKEN BGOACS isshown in Fig. 1. This system consists of 13 segments of BGO crystals (six thin trapezoidal- (Ttype), six long trapezoidal- (L-type) and one
hexagonal-type (H-type» and seven photomultiplier tubes (PMT's). Six pairs of T - and L-type
crystals and one H-type crystal are connected to the
PMT's independently by light guides so that thissystem can accept high counting rates.
Performance of the system was tested with r-rays
from a 60Co source. Figure 2(A) shows r-ray
spectra taken with and without Compton suppression. The suppression factor, the ratio between
the counts in the unsuppressed and suppressed
spectra, is given in Fig. 2 (B) as a function ofenergy. The average suppression factor below 1,130
keV is about 4. Broad unsuppressed peak at theCompton edge in the suppressed spectrum is dueto the entrance hole of the ACS through which theback scattered r-rays can escape. The effectivenessof T -type crystals could be proved comparing thewidth of these peaks in the suppressed spectra takenwith and without them.
These results were well reproduced by the MonteCarlo calculation as shown in Fig. 3 (A), (B).
The size of the Ge detector and the solid angle
considered in this calculation are the same as thoseof the test measurement mentioned above. The
assumed materials between the Ge detector and
BGO crystals are as follows: (1) 4 mm radius Ge
P-type core, (2) 0.7 mm Ge dead layer, (3) 3 mm Al

10'

UNsuppnESSEO

z

:>
o
u

suppnESS EO
10'

(A)

la'

500

1000

io

1500
CHANNElS

2000

1500
CHANljEt S

2000

(8)

a:

....o
o

~

u.

10

15

I

I

20 em
I
500

Fig. 1. Crosssectional view of BGOACS. The system consists of three types of crystals, thin trapezoidal-(T-type),
long trapezoidal-(L-type) and hexagonal-type (H-type).

1000

Fig. 2. Measured r-ray spectra of 60Co with and without
Compton suppression.

153

M. Fukuda, et al.

10 5

lOOO~-~l~-------'r--------------'I------'~(A)

SINGLE MODE

>

10 4

'.;"

...J
W

Z
Z

;2 500

u

"-

10 3

(J")

Unsuppressed

t-

N

Z
:=J

o
U

J".~

O~------:~~~~~~~·'~-~Ir~--------'--~\ ~I~____~
Lv.-

__

9L______~I_______l_OO~IL_______~I___2_0_0~~
5
10
15
20

o

GAMMA ENERG ),(HeV)I OOOrr----I----------r-r------------,,-----~

1 0 0~~~-L~~~~~~~~~~~~~~~~

o

66

132

198 264 330 396 462
Channel528

594 660

726(8)

SUM MODE

...J
W
Z
Z

(il )

8.35

<:
J:
U

FWHM
6 . 8%

500

"tZ
:=J
Cl
U

0

9

0.00 0Fig. 3.

66

132

198 264

330 396 462 t 528 t 594 t 660 ' 726
ChannelCalculated spectra as same as those of Fig. 2.

0

10

5

GM1 ~I A ENE RG)'

2[J15
( He V )Fig. 5. The spectra of high energy r-rays from the reactionllB(p, r)12C, A, taken by the center BGO; B , taken bysumming the signals from all the BGO.

40000~----------------------------~BGO (50.8¢ X 50.8mm')
R878 (HTV)gate on 423 keYwith BGOCSS

~
c

::J

20000

o

(.)

'" '"
'"

.,

<?

'"

<0'"
:z

::>

o

).0

~

200

100

\I')

..
CD
C?

gate on 423keV

Channelwithout BGOCSS..........
<0",,,,"'''''''

Fig. 4. Gamma-ray coincidence spectra of 218Ra gated on the
423 keY r-ray taken with (upper) and without (below)
BGOACS.

housing and (4) 0.5 mm BaS04 reflector. The
calculations were carried out with various thicknesses of these materials, which produce the bumpof the back scattering, affect the suppression factor
significantly. According to the calculation, this factor
could be improved to be about seven without theP-type core, dead layer, alminum housing and

Fig. 6. Gamma-ray spectrum of 60CO taken by the center
BGO.

BaS04 reflector.
Four sets of BGOACS were used for the r-r
coincidence experiment with the 2osPb(13C, 3n)21SRa reaction at E=75 MeV. A background was
reduced by factors of two and four for the singles
and coincidence spectra, respectively. Four million
coincidence events were collected in 60 hours. This
result is compared in Fig. 4 with that obtained from64 million events run with two Ge(Li) detectors
without BGOACS.
The BGO shield can also be used to detect highenegy r-rays by replacing the Ge detector by a
BGO crystal. This set-up is useful because (1) abetter resolution is easily obtained by using a small
crystal and (2) the smaller size of this system com-

154

M. Fukuda, et aZ.

paring with a similar set-up of other kind of scintillators having the same efficiency reduces a background such as cosmic rays. The system was tested
by using the 11 B (p, r)12C reaction. Proton beams
of 1. 4 MeV were derivered from a Van de Graaff
accelerator of Tokyo Institute of Technology. Theenergy spectra are shown in Fig. 5. Spectrum A

was taken by using only the center detector (2" ifJ X
2" BGO). Spectrum B was taken by summing thesignals from all BGO crystals. The energy resolutions of 6 and 5% were obtained for 12.79 and17.23 MeV r-rays, respectively. The characteristicsof the center BGO may be seen in Fig. 6.

155
RIKEN Accel. Progr. Rep. 18 (1984)

111-5-2.

A Compound Counter System for High-Energy
Gamma-Ray Detection
S. Kubono, * M. Tanaka, * M. Ishihara, K. Morita,
S. Kato, ** H. Kawakami, * and C. Konno***We have constructed a counter assembly for
detection of high-energy gamma rays of several tens
MeV. Figure 1 shows the configuration of thedetectors composing the assembly. The central
piece of NaI crystal with a hexagonal shape is dosely
packed with 6 pieces of trapezoid N aI crystal. Plastic
counters are placed further to cover these detectors.
The non-cylindrical shapes for NaI were adopted
for ease of fabrication and packing. The lengthof the central detector is 6" and other dimensionsof the detectors may be inferred from Fig. 1. The
seven NaI crystals are lapped with stainless steel
walls of 0.5 mm in thickness. Light signals fromeach crystal are collected through a light guide
onto a separate photomultiplier.
Gamma rays are incident on the central detector
through a Pb collimator. Energy deposition of
gamma rays via the photo-electron, Compton scattering, and pair creation processes will occur primarily in this detector. The surrounding N aI crystals
will serve to detect partially-slowed secondary
electrons or Compton-scattered and annihilation
photons, which have escaped from the central detector. The plastic counters will serve to detectcosmic rays and other radiations from outside.
The detector assembly can be operated in several
modes such as (A) coincidence mode, in whichcoincidence signals between the central and surrounding N aI detectors are summed up to produce
a total-energy singnal, and (B) veto mode, in which
signals from the central detector are registered only
when no signals are present on the surrounding
detectors. In any modes, signals from the plastic* Institute for Nuclear Study, University of Tokyo.
** Department of Education, Yamagata University.
*** Department of Science, Kyoto University.

Plastic
Nal

j

~C;
10

o

~

o

10

20cm

Fig. 1.

Schematic view of the counter assembly for highenergy gamma-ray detection.

counters are used to veto registering data.
The performance of the setup was tested by measuring gamma rays from the (p, r) reaction on a
BN target using 6. 95 MeV protons from the INS
cyclotron. For the 22.93 MeV transition corresponding to 11 B (p, ro)12C g .s., detection efficiency interms of total-energy peak was about two times
larger in mode A than in mode B. On the oher hand,
better energy-resolution of 4.50/0 was obtained inmode B than that of 6.00/0 in mode A. The reduced
resolution for coincidence mode operation may berelated partly to use of crystal of poor quality forsurrounding detectors and partly to the thicknessof the stainless-steel wall, which may absorb energyof transmitting electrons.
The system has been proved useful for detectionof high-energy gamma rays and being used for the
study of the radiative capture reaction 12C+12C.
Meanwhile, improvement of the performance is being
pursued through re-fabrication of NaI crystal with
better quality.

156
RIKEN Accel. Progr. Rep. 18 (1984)

111-5-3.

Liquid Ionization Chamber

S. Konno, T. Takahashi, and K. Masuda

Liquid ionization chambers have been used as
nuclear radiation detectors. The mediums used inthese chambers include liquid rare gases, such asargon and xenon, which have relatively large electron
mobilities and high ionization yields. In spite of suitable properties, liquid rare gases have not beenused widely because of inconvenient low-temperature techniques.
Since 1968, we have studied ionization in liquidrare gases.1) -3) Now we are looking for what is called"warm liquids" which are usable at room temperature. Tetramethylsilane and tetramethylgermane
seem to be such liquids; their physical properties
are summarized in Table 1.
One of the serious problems is due to difficulty inremoving electronegative impurities which capture

Table 1.
LiquidTetramethylsilane
Tetramethylgermane
Liquid argon
Liquid xenon

electrons produced by ionization and decrease output signals from detectors. We thus contrived purification system shown in Fig. 1. In the first step of
the purification, liquid in a lower vessel is evaporated
and condensed into an upper vessel. Then a part ofvapor is cautiously pumped through a glass cold
trap. After distillation, the condensed liquid wasadmitted into a lower vessel. These procedures
are repeated. In the second step, the vapor of theliquid was passed through a spiral tube filled with
Molecular Sieves.
The ionization chamber, shown in Fig. 2, has athin window (zero potential) and a collector electrode(positive potential). Incident radiation through thewindow produces electron-ion pairs in the liquid.
Most of them are separated by the applied electric

Physical properties of liquids.

p (g·cm- 3 )Tb (K)Tm (K)

p. (cm2V- 1 s-l)0.648(293 K)
1.006(293 K)
1.41(83.8 K)
2.96
(161.4 K)

299.7

171.0

90 4 )

316.6

185.2

90 4 )

87.3

83.8

475 5 )

4.3

165.1

161.4

2,200 5 )6.4

Gp, density; Tb, boiling point; T m , melting point; p., low-field electron mobility; G, ionization yield(number of electrons per 100 e V).

"Gauge "~:lfT::::";::J(l~~==~ To chamber

Cold trap

Fig. 1.

Liquid purification system.

Fig. 2. Liquid ionization chamber.
A, window; B, collector electrode; C, insulator; D, liquid
inlet pipe.

S. Konno, et al.

field and the signal charge would be induced on thecollector electrode by the drift of electrons.
The construction of the purifier and the lOmzation chamber are now under way.
References
1)

S. Konno and S. Kobayashi: Sci. Papers I. P. C. R., 67,
57 (1973).

2)

157

T. Takahashi, S. Konno, T. Hamada, M. Miyajima,
S. Kubota, A. Nakamoto, A. Hitachi, E. Shibamura, and
T. Doke: Phys. Rev. A, 12, 1771 (1975).
3) K. Masuda, T. Doke, and T. Takahashi: Nucl. Instrum.
Methods, 188, 629 (1981).
4) W. F. Schmidt: Can. J. Chem., 55, 2197 (1977).
5) L. S. Miller, S. Howe, and W. E. Spear: Phys. Rev., 166,
871 (1968).

158

RIKEN Accel. Progr. Rep. 18 (1984)

111-5-4. Use of Charge Integrating ADC's with Pulse ShapeDiscriminators for Neutron-Gamma Discrimination

J. Kasagi, T . Murakami, and T. Inamura
A neutron-gamma discrimination method usinga CANBERRA 2160 pulse shape discriminator(PSD )1) is a simple and convenient one to suppress
gamma rays in neutron detection system since only
anode output of a photomultiplier is required by
the PSD. In our neutron multiplicity filter systemat the cyclotron laboratory,2) which was constructed
for in-beam gamma-ray spectroscopy for neutron
deficient nuclei, anode output pulses of photomultipliers of six neutron detectors (NE213) are fed
directly into the PSD's. When only the neutron
event information is required, output pulses of the
PSD's in n mode can be used as neutron event pulses
after adjusting the strobe delay. In practice, however, the pulse shape information of each event isrequired for the later off-line analysis, since thequality of the n-r discrimination depends on thepulse height of the detector output. In this case,
output pulses of the PSD's in n+r mode are usedas stop pulses of CAMAC TDC's. The detection
system becomes complicated because output pulsesof the constant fraction discriminator (CFD) must
be delayed to be accepted within a time interval of
the TDC (typically 250 ns). Furthermore, the computer busy time increases because unwanted gammaray events cannot be reduced by adjusting the strobe
delay.
We have found a simple method to obtain pulse
shape spectra without TDC's, realizing to reduce
unwanted events easily. The method is an application of the time measurement by charge integrating
ADC's recently reported. 3) We have measured total
charge of the output pulse of the PSD in n mode
instead of measuring the time difference between
output pulses of the CFD and the PSD in n + r
mode.
The pulse shapes at various points of the PSD
circuit for nand n + r mode are shown in Fig. 1 according to the notation in Ref. 1. In n + r mode,
the leading-edge of the output pulse is defined by
the zero-crossing time of the RC-shaped input
signal when the strobe pulse is covering the righttime region. Thus, the time difference between output pulses of the CFD and the PSD gives the pulse
shape information of the input pulse. On the other
hand the leading-edge of the output of the PSD inn mode is defined by the leading-edge of the strobe
pulse triggered by delayed CFD output, and no
pulse shape information is available. However, thetime of the tailing-edge is defined by the zerocrossing time of the RC-shaped input signal. Therefore the width of the output pulse gives the pulse
shape information. This information can be digitized easily by using the charge integrating ADC
since the output of the PSD is provided by a stablecurrent source of 16 mAo The fact that the pulse
width of the gamma-ray event is always smaller
than that of the neutron events makes the reduction of unwanted gamma-ray events possible without losing the pulse shape information. It can bedone by adjusting the strobe delay. The output of
the PSD in n+r mode might be also used to obtain the pulse shape information by the charge
integrating ADC. In this case, the output pulse
width of the gamma-ray event is larger than that of
the neutron event because the tailing-edge of theoutput pulse is defined by the tailing-edge of thestrobe pulse. Thus, the neutron events can beeliminated without losing the pulse shape information.
Pulse shape spectra obtained from as" X 3"
neutron detector with a 2 mCi Am-Be source arecompared in Fig. 2. The spectrum measured by theconventional time difference method is shown in
t=o

Input
11/

rIll

A2

n

11/

\1\

Inverted A2

rWI
III

n

Strobe ~--------,
n+ r mode I - - - --- - - ----nr--rm

Outputn mode ~--------,

Fig. 1. Pulse shapes and time relationship between the pulses
at various points of the SPD circuit. A2 is the output of ahigh-gain limiting amplifier.

J. Kasagi, et al.

SOD

---l
W
Z
Z

0

-<

:c SOD
u

"'-

if)

tZ

::::>

a
u

0

SOD

200

400

600

CHANNEL NUMBER

800

Fig. 2. Pulse shape spectra for an NE213 detector.
(a) Measured by the conventional time difference methodwith the TDC (125 ps/ch), (b) measured with the charge
integrating ADC for the PSD in n mode, (c) for the PSD inn+r mode.

Fig. 2 (a), while in Fig. 2 (b) is the spectrum obtained by the charge integrating ADC for the PSD

159

in n mode and in Fig. 2 (c) for the SPD in n+r
mode. The output pulse of the PSD was attenuatedby 16 dB in order to obtain the charge-time ratio of
2 pC/ns. As can be seen in Fig. 2, the spectra obtained by the present method give the same qualityof the n-r separation as that of the conventional
method.
The present method has been employed for n-r
discrimination of our neutron multiplicity filter system with simpler cable connection and data taking
program. The main advantages of this method are
as follows:(1) The pulse shape information from neutron
detector can be obtained only from the PSD output,
independently from the CFD output.
(2) The reduction of unwanted events can berealized easily without losing the pulse shapeinformation.
References
1)
2)
3)

P. Sperr, H. Spieler, M. R. Maier, and D. Evers: Nucl.
Instrum. Methods, 116, 55 (1974).
T. Murakami, J. Kasagi, H. Harada, and T. Inamura:
RIKEN Accel. Progr. Rep., 17, 125 (1983).
W. Z. Venema: Nucl. Instrum. Methods, 219,257 (1984).

160

RIKEN Accel. Progr. Rep. 18 (1984)

111-5-5.

Particle Identification with a 8aF2 Scintillator
T. Murakami, J. Kasagi, T. Inamura, and M. Ishihara

We have tested a BaF2 scintillator as a charged
particle detector since the BaF2 scintillator is considered to be a modular detector of a multi-detector
system for experiments on the SSC to detect charged
particles together with r-rays.
Attractive features of the BaF2 scintillator as a
r-ray and particle detector with moderate energy
resolution are the following.
(1) Time resolution of about 150 ps has been obtained because of the existence of the fast
decay component in the scintillation light. 1)(2) Stopping power for charged particles is muchlarger than that of the plastic scintillator, sothat 200 MeV proton can be detected with
BaF2 crystal of 10 cm in thickness.

;-te'PhenYI

8aF2

R329

Fig. 1.

Electronics diagram used for particle identification.

128

I

I

Gamma-ray efficiency is about 300/0 higher
than that of NaI.
(4) Energy resolution for charged particles IS
better than that of a plastic scintillator.2)
In addition, pulse shape difference between rrays and particles has been observed. 2),3) Thus, ourimmediate interest is to investigate the possibilityof particle identification by a pulse-shape-discrimination technique.
The BaF2 crystal used in the present work wasa high purity one made by Ohyo Koken Kogyo Co.,
Ltd. It was rectangular in shape with dimensionsof 2 cm X 4 cm X 1 cm. In order to detect thefast component of the scintillation efficiently, pterphenyl was evaporated on the crystal surface
as wavelength shifter, and the crystal was wrappedwith a conical mirror with a 1 cm diameter hole.
The crystal was optically coupled to a photomultiplier(Hamamatsu R329) with usual silicone grease.
Figure 1 shows a schematic diagram used for thepulse shape discrimination. The fast component of
the scintillation light was measured by a chargesensitive ADC shown as QDC in the figure. A
CAMAC data taking system4) was used to collectand analyze data.
The particle identification was tested for the
(3)

I

200

nate .d

Ed=20 MeV

8

-

96

C + d
Ed = 20 MeV.

100....c:

.

-.l
W

E 64

:z:
:z:

o

u

<>::

o

I

....

..

.. e_

Q)

c:

o
a.

p-gate= 30°.""-"'"

Or-~--~---+--~~-r~~~4-~

"(f)

I/)

d-gate

I-

co

:z:

U.

::J

o

-

32

Tota I Li ght out put

Fig. 2. Contour plot of total light output vs. fast componentof light from the BaF2 scintillator.

u

..

100

~o

.--......;..
40

..
60

80

100

CHANNEL NUMBER
Fig. 3. Pulse height spectra for protons (upper) and deuterons (lower).

T. Murakami, et al.

C+d reaction. A 20-MeV deuteron beam from thecyclotron was used to bombard C-foil of 5 mgjcm2
in thickness. The BaF2 detector was placed at 30°
to the beam axis.
Obtained two-dimensional spectrum is shown in
Fig. 2. As expected from the observation for r-rays
and a particles,2),3) the light output of the fast component decreases for heavier particles. Clearly
separated loci are observed in the spectrum, namely
one corresponding to protons and the other todeutrons. Gamma rays (electrons) are well separated
from the charged particles. However, the separation
is not so good for the region of Ep ~ 10 MeV
where a particles are also observed. Two-dimensional measurement with time of flight vs. total
light output is necessary for such low energy
particles. The excellent time resolution of the BaF2

161

detector would make the particle identification
possible by measuring flight time.
In Fig. 3 are shown projected spectra for protons
and deuterons. Several peaks from the 12C(d, P)13C
and 12C(d, d)12C reactions are clearly seen in the
spectra. The energy resolution of about 450 ke V
for Ed=20 MeV was obtained.
References
1)

2)
3)
4)

M. Laval, M. Moszynski, R. Allemand, E. Cormoreche,
P. Guinet, R. Odru, and J. Vacher: Nucl. Instrum. Methods, 206, 169 (1983).
T. Murakami and J. Kasagi: unpublished.
K. Wisshak and F. Kapeler: Nucl. Instrum. Methods, 227,
91 (1984).
T. Inamura, T. Murakami, J. Kasagi, H. Kumagai, and
H. Gono: RIKEN Accel. Progr. Rep., 17, 124 (1983).

162

RIKEN Accel. Progr. Rep. 18 (1984)

111-5-6.

Test of MCP and PSD Using X-Rays and Electrons
H. Kumagai, Y. Itoh, T. Koizumi, H. Shibata, and Y. Awaya

X-ray (13-16 keY) is emitted from a point sourceof a diameter of 1 mm, passes through a thin AIwindow, and then hits the M CP surface uniformly.
An applied voltage for each MCP was 1 kV and apotential difference between MCP and PSD wasabout 20 V; under these conditions, an output pulse
height distribution is optimized.
A position signal was processed by means ofanalog devices and then fed to a pulse height
analyzer (see Fig. 2).
An observed spectrum is shown in Fig. 3. As the
X-rays hit the MCP surface uniformly, this spectrum reflects the position dependence of the detection efficiency of MCP and PSD assembly. The
detection efficiency on the studied area was fairly

A posltIOn-sensltIve electron-spectrometer, inwhich a tandem micro-channel-plate (MCP: Hamamatsu Photonics) and a Si-position-sensitive detector (PSD: Hamamatsu Photonics) are used, wasconstructed and a performance of the spectrometer
was tested. The spectrometer was used to measure
the energy of scattered and ejected electrons inelectron-atom collisions, and spectra of elasticallyscattered electrons and Auger electrons were obtained. During the test, it was noticed that a detection efficiency is not always the same on every
position of the MCP-PSD assembly. Therefore wetested a uniformity of the detection efficiency of theassembly itself using X-ray and electron sources.
An experimental setup is shown in Fig. 1. The

Vacuum waif
Mask
\

MCP

,'I'

~

(

/
/

~I

X·ra y source (1 ~)
13 - 16keV

!

2.17"

i=-

l!)

uit

V
AI foil·
145'

~

';

~

~

~

II

FlO!4-11)
Fl094-21
B

ti'PSD S1352(34 X2.5)
C

A

~

171.5

Fig. 1.

Experimental setup to measure the uniformity of the detection efficiency.

,----------T----------,:I
S~. ·PSD·:I B
51M:I .
I
I
I

I
I

i

I

PHA

I
I
I
I
I

X-Ray ----:-:-;~
I
I

I

I
I
I
I

I
I
I
I
I

I
I

L_

+ 1980V

Fig. 2.

+2000V

Circuit diagram for a position sigal processing.

H. Kumagai, et al.

-;;:- ,1.23 r - - - - - - - - - - - - - - ,o.....

2S. 1..02~ .0.82c:
co..c: .0.61
~

.!!?
c:
o

:::l

0'.4:1o

1.024Channel number

Fig. 3. Observed detection efficiency of the MCP-PSD
assembly tested.

flat but nQt cQnstant; the deviatiQn frQm the unity
is abQut ±5O;o when the efficiency is nQrmalized
at the center .of the M CP. This deviatiQn may be

163

caused by the MCP .or PSD, .or both. When thetest was repeated after the PSD was turnedby 1800 , the same PQsition dependence remains.on a spectrum. Therefore, the observed PQsition
dependence is considered t.o be caused by adifferent gain of the M CP at a different PQsitiQn.
This tendency .of the P.ositi.on dependence was als.o.observed when the assembly was eXP.osed to straythermal-electr.ons, which hit MCP surface fully
rand.omly, fr.om an i.on-gauge.
C.onclusi.ons of these tests are: (1) the unif.ormity.of the PSD is go.od en.ough and (2) the detecti.on
efficiency .of the M CP has s.ome P.ositi.on dependence.of ab.out ±5O;o deviati.on from unity.

164
RIKEN Accel. Progr. Rep. 18 (1984)

111-5-7.

One Dimensional Position Sensitive Parallel Plate
Avalanche Counter
H. Kumagai, S. H. Be, M. Ishihara, Y. Ikegami,
M. Fuse, and E. Gotoh

A parallel plate avalanche counter (PPAC) is awell-known heavy-ion detector widely used fornuclear physics and atomic physics. The PP AC has
an excellent timing property and a high counting
rate capability. It is useful for a large area position
sensitive detector. Furthermore, there are little
problems with radiation damage.
We have constructed a protDtype PPAC to study
fundamental characteristic of the CDunter and to.
develop improved electronic circuits for fast timing
measurement. Through this work, we aim to establish basic prDduction techniques of larger area
PPAC detectors required for future use at the
RIKEN SSC.
Figure 1 shDws the cross sectional view of thedetector. The detector consists of two different
PPACs.
(1) A position sensitive PPAC which consists ofan anode, grid, and cathode. The anode and cathodeare made of 2.5 pm Hostaphan foil evaporated with agold layer (60 pg/cm 2 ) which has an active area Df
30 x 105 mm 2 • The grid consists Df 40 pm-diameter
tungsten wires strung 2 mm apart, and is gilded with
gDld. All wires are connected to each .other by aresister Df 200 Q. The respective distance between
the anDde and grid or the grid and cathode is 1.5
mm fDr either case.
(2) A timing PPAC. This PPAC cDnsists of ananode and cathode Df the same kind as in formercase but withDut a grid. Two PPACs are set up inparallel 10 mm apart frDm each other as shown in
Fig. 1.

Fig. 1. Cross sectional view of the detector . .
1 : Position sensitive PPAC, 2: Timing PPAC, 3: Gas inlet,
4: Gas outlet,S: Flange, 6: Stainless box, a: Anode,
g: Grid, c: Cathode.

The detector hDusing cDnsists of a flange, Dn
which two counters and seven coaxial CDnnectDrs
are mDunted, and a bDx having two windows (30 X
110 mm 2 ) cDvered with 2.5 pm HQstaphan foil. In
additiDn, two extremly small fast-preamplifiers(diameter 4 mm, thickness 2.5 mm, gain 10, andbandwidth 1.2 G Hz) are mounted directly Dn the
counters and Dperated in the gas atmDsphere.
We have chosen isobutylene as a cDunting gas
which seems best for a fast timing signal (Ref. 1);
further, it is cheap and easy to handle. A gas-feedsystem is shown in Fig. 2. The gas pressure is kept
CDnstant at about 10 Torr by adjusting a flDW ratePPAC

VACCUMCHAMBER

Fig. 2. Diagram of the gas-feed system.
Vl, V2: Needle valves, Vo, V3, VL, VR, Vn: Shut-off valves,
V4: Bellows valve, Tl-T4: Flexible tubes, ]I-J3: Tube
joints, PO-P2: Vacuum gauge ports, R. V. P: Rotary vane
pump, D. P: Diaphragm pump.

165

H. Kumagai, et al.

Fig. 3.

Block diagram of the electronic system.
FPA: Fast-preamplifier.

of the gas with needle valves V1 and V2 •In order to avoid backstreaming of oil- and watervapor from a rotary vane pump to the system, andto prevent deterioration of the oil' caused by the gas,a foreline sorption trap is mounted on the inlet ofthe pump. A diaphram pump is used to exhaust
the absorbed gas evolved from the sorption trap,
when the trap is regenerated by heating.
Figure 3 shows a diagram of the electronic system
for measurement of position resolution of thedetector and time resolution. The charge division
method is used for position measurement. The
signals from both ends of the grid are received withcharge · sensitive amplifiers and then amplified withimproved SIN through filter amplifiers. The position signal is obtained by dividing one-side signal
by total signal which is obtained by summing up

two signals from both ends of the grid.
The timing property is observed from measurement of the flight time of an a-particle between the
two transmission PPACs. The fast timing signals,
taken off at the anodes of the PPACs, are fed via
fast-preamplifiers mounted on the counters into
fast timing amplifiers and processed by constant ·fraction discriminators, and then sent to a timeto-pulse amplitude converter. By using the above
fast-preamplifiers, an improved time resolution is
expected in this system. The above position data
and timing data are stored in a multichannel pulsehight analyzer.
Reference
1)

H. Stelzer: Nucl. Instrum. Methods, 133, 409 (1976).

166
RIKEN Accel. Progr. Rep. 18 (1984)

111-5-8.

Test Machine for Ion Guide Isotope Separator On-Line
K. Morita, T. Nomura, T. Inamura, H. Kudo, and K. Sueki

The ISOL (Isotope Separator On-line) technique was developed for the study of very shortlived and rare radioisotopes. In recent years theIon Guide Isotope Separator On-Line (IGISOL)
has been developed l ) as a new type of ISOL which
does not require an ion source. In the case of
IGISOL, reaction products emitted from a target
are slowed down and stopped in helium gas. Although most of ionic reaction products are neutralized in the gas, some amounts of them (1-10%)
2

He gas=1'===1

Fig. 1. Schematic diagram of the test machine system for
IGISOL.
1, Vacuum chamebr; 2, Faraday cup; 3, Target box; 4,Skimmer; 5, Extraction electrode; 6, Einzellense; 7 , Vacuum
guage (B-A guage); 8, Analyzer magnet; 9, Electron multi.
plier.

hold a charge state of + 1. And then by using anelectrostatic field, these ions are extracted and accelerated for mass analysis. Because an IGISOL
system have no ion source, this system will enable
us to study more kinds of elements than those by
an ordinary type ISOL with an ion source.
In order to develop the IGISOL system we haveconstructed a test machine. This test machine iscomposed of four parts: (1) a target box, (2) an extraction and acceleration system, (3) a mass analysing
system, and (4) a detection system, Fig. 1 shows aschematic diagram of the total system. We use thedipole magnet as a mass analyzer and an electron
multiplier for detecting ions. Accelerating voltage
can be set 3-4 kV, and voltage between target box
and skimmer can be set 1SO-ZOO V.
The vacuum chamber outside the target box is
evacuated by a mechanical booster pump, and theacceleration part is evacuated by a diffusion pump.
These two parts are separated by a skimmer witha hole of 1 mm~. While the pressure in the target
box is kept 10-30 Torr by flowing helium gas, thatof outside the target box is kept ,,-,10- 2 Torr, andthat of the acceleration part ,,-,Z X 10-5 Torr. A
cross sectional view of the target box is shown in
Fig. Z.
A test experiment was done by using 30 MeV abeam from the cyclotron with a natural titanium
target. Although there are many peakes seen in themass spectrum, they correspond to ions of the gases
ionized by the beam. From the yield of a 4He+
peak in the spectrum, the total efficiency of this test
machine is estimated to be less than 10-8 • Modification of the target box and other parts to enlarge
the efficiency will be required.
Reference
1)

Fig. 2.

Cross sectional view of the target box.

J. Arje and K. Valli: Nucl. Instrum. Methods, 179, 533(1981).

167
RIKEN Accel. Progr. Rep. 18 (1984)

111-5-9.

A Coulomb-Excitation Mossbauer Spectrometer
N. Sakai, F. Ambe, and K. Asai

A Mossbauer spectrometer for r-rays from Coulomb-excited states has been designed and constructed. Since most of Mossbauer r-rays createdby Coulomb excitation have relatively high energy,
it is required that both a source and an absorber
are held near liquid-N2 temperature to increase therecoilless fraction.
The side view of the spectromater is shown in
Fig. 1. It is divided into two parts: (1) a transducer
and its attachment to an absorber holder, (2) atarget chamber with a liquid-N2 cryostat.
The heavy-ion beam comes in along the upward
direction normal to the plane of the paper, andstrikes a target which makes an angle of 45° to thebeam line. Then, Coulomb-excited Mossbauer
nuclei recoil out of the target and are implanted into
a fixed stopper. This sotpper, which acts as a Mossbauer source, is cooled by a cold rod suspended
from a liquid-N2 bath having a capacity of 1.5 litre.
Liquid N2 is supplied automatically from anotherliquid-N2 container. The Doppler-modulated absorber is also cooled through springs connected

to a cold box of the cryostate. The target and stopper
holder can be pulled up, and the position of thebeam can be adjusted by observing fluorescenceemitted from an inclined quartz plate which isjoined to the target holder. The fluorescence is
detected through a viewing window at the bottomof the target chamber.
In order to keep the vacuum of the linac clean,
the transducer is placed in a separate chamber so
as to avoid the problem of gas desorption from thetransducer. The transducer chamber is separated
from the target chamber by a soft bellows. It issufficient to evacuate the transducer chamber by arotary pump so that there in no severe pressure difference between the transducer chamber and thetarget chamber. The rod of the transducer can bereleased at the positions A, B, and C denoted inFig. 1.
The r-rays penetrating through a Be window,
which is placed at a right angle to the direction of
the ion beam, are counted by a Ge detector.

~R.p.

Fig. 1. In-beam Mossbauer spectrometer for r-rays from Coulomb-excited nuclei.
1, Liquid-N2 bath; 2, target and stopper; 3, absorber; 4, Be window; 5, springs;
6, quartz plate; 7, safety stopper; 8, transducer.

168

RIKEN Accel. Progr. Rep. 18 (1984)

IV.

NUCLEAR DATA
1.

Status Report of the Nuclear Data GroupA. Hashizume, Y. Tendow, and T. Nozaki

Since the last Meeting of the Nuclear Data
Centers in October, 1983, in Obninsk and MOSCOW,l)RIKEN Nuclear Data Group has recognized theimportance of compilation of Data of chargedparticle induced reactions useful for productionof radioactive isotopes in biomedical use.
The compilation of data has been started thisyear by keeping contact with the Nuclear Data
Section (NSD) in IAEA and other data centers.
Our primary interest is in the reaction crosssections which are concerned with production of thefollowing isotopes: l1C, 13N, 150, 18F, 28Mg, 52Fe,
67Ga, 74As, 77Br, 82Br, 77Kr, 81Rb, 82mRb, 1111n,
123Xe, 127Xe, 1231, 1241, and 125I.
Because this period is the time of foundation andconsolidation of the Group, efforts were made fortwo directions, policy,l) and technics. The activityof the Group has formally been approved as oneof the projects in the accelerator division. A nationwide advisory group consisted of 4 physicians, 5
physicists, and 4 chemists has been organized tokeep close relation with other data groups and withexperts in various fields in Japan. The first meeting
was held in February and the second in November,
1984.
Technical activities(1) We use the center computer (FACOM M
380) of RIKEN as a host computer for compilationof data. The majority of data are registered in the
EXFOR format. Curve reading techniques for datacompilation have been established by using a curve
digitizer and a mini-computer. The mini-computercan be connected on-line to the host computer.
Several programs were developed to support thecompilation.
(2) Implementation of some programs of the
EXFOR and Dictionary system obtained from NDS

are now going on. Check New Entry Run andGenerate Dictionary Run are now under investigation. The book-keeping programs are in operationand the second trans-tape data are treated by these
programs.
(3) Two data tapes (ROOl, R002) have beentransmitted to NDS. The contents of the firsttape were consisted of 10 entries (37 subentries) andthose of the second tape consisted of 6 entries (140subentries) and corrected entries of the first. The
first trans-tape contained the data of excitation
function in the region of about A= 130 and thesecond contained those of about A= 11. The latter
consisted of the differential cross section data, because in the region relatively few total production
cross section data are available. We consider that
this preliminary data compilation is a case study
because whole Check Run program is not yet inoperation.
(4) Bibliography: Lists of references which areconcerned with our subject are being accumulated
continuously and checked on the coverage of theexisting EXFOR files.
(5) Other activities are concerned with the masschain evaluations of nuclear structure data. In
cooperation with JEARI group, we have finishedthe evaluation of experimental data pertaining tomass number A= 129 nuclei. 2) Evaluation of A=
120 chain has been almost finished and is underinspection of other data groups in Japan.
References
1)

2)"Report on the 7th IAEA consultants" Meeting of
Nuclear Reaction Data Centers, INDC (NDS)-154(1984).
A. Hashizume, Y. Tendow, and M. Ohshima: Nucl. Data
Sheets, for A=129, NDS 39, 551 (1983).

169

RIKEN Accel. Progr. Rep. 18 (1984)V.

ACCELERATOR DEVELOPMENT
1.

Present Status of the RIKEN Ring Cyclotron Project
H. Kamitsubo

The project for construction of the K=540 MeV
separated sector cyclotron (Ring Cyclotron) at
RIKEN has progressed as intended in 1984. The
cyclotron vault was almost completed in Marchand assembling of the sector magnets in the vaults
was carried out from April through June. As described previously, each sector magnet can beseparated into thirty pieces, that is, two poles andtwenty eight slabs of the yoke, for the convenienceof transportation from the factory to RIKEN. The
slabs of the yokes were transported by land whereas
the poles were brought by ship to Tokyo and thenby land to the institute. Four sector magnets wereassembled at the same time on the base in the cyclotron vault by adjusting their relative positions toeach other precisely. Six invar bars were set connecting the fixed points on the upper faces of four
sector magnets to measure their displacements
to each other. Change in the relative positions has
thus been monitored continuously since then.
Power supplies for the main and trim coils werebrought into the cyclotron vault in August andtheir tuning up and inspections of the current stability have been carried out. The stability better
than 2 X 10-6 was realized for the main coil currents.
Measurements of excitation characteristics andmagnetic field distributions will start in January,
1985.
The components of the Ring Cyclotron other than
the sector magnets were ordered to SUMITOMO
Heavy Industries, Ltd. and the final design for
their fabrication have been performed. Design ofthe valley chambers was almost finished and vacuum
pumps other than cryopumps and vacuum elements
such as valves, vacuum gauges, and Q-mass analyzers were on order. Development of the cryopumps having a pumping speed of 10,000 lis isin progress.
As described in a previous report, we decided
to adopt a new type resonator having two verticalstraight stems on the upper and lower sides of theaccelerating electrode (dee) and also two moving
boxes as a frequency changing device. The resonatoris made of copper clad stainless steel fabricated by adiffusion-welding technique. In order to realize

bette~ cooling efficiency there are channels forcooling water on the copper clad side of the stainless steel.
Basic design of the RF system was finished andthe system was ordered to Denki Kogyo Co. ,Ltd.
It consisits of a master oscillator, wide band amplifiers, and a final power amplifier for which a
Siemens RS2042SK tetrode is used.
A computer-aided control system is introduced forthe present accelerator system. The main systemcomposed of three MELCOM 350-60/500 computers, disks and I/O devices, and networks of the
CAMAC as well as GP-IB will be used for controlof the Ring Cyclotron and two injectors. New
CAMAC interfaces, named CIM (Communication
Interface Module) and DIM (Device Interface
Module), were developed. The first system of
MELCOM 350-60/500 and several sets of the CIM
and D 1M were delivered and are being used fordeveloping the control program. They will be used
for the field mapping of the sector magnets.
Design of the injection elements such as bending
magnets, magnetic, and electric inflection channels
were finished. The magnetic elements will be completed in next spring and will be attached to thesector magnets to measure their effects on the field
distributions of the main magnets. The beam transport line between the injector linac and the Ring
Cyclotron was designed to realize the better matchingof two accelerators extensively carrying out the beam
dynamical calculations with the computer program
TRANSPORT. Prototypes of beam diagnostic
elements such as emittance and profile monitors
and a phase probe were fabricated and tested.
Discussions on the experimental facilities to beconstructed at the early stage of beam acceleration
started in this period by both inside and outsideusers. Experiments on nuclear physics and biological studies are expected to be pursued with thefirst beams from the Ring Cyclotron.
Construction of the experimental halls as well as
control and counting rooms started in December,
1984. Design of the radiation monitoring system is
III progress.

170
RIKEN Accel. Progr. Rep. 18 (1984)

V-2.

Sector Magnets for the RIKEN

sseS. Motonaga, H. Takebe, T. Wada, A. Goto, I. Takeshita,
J. Fujita, H. Kamitsubo, J. Abe,* H. Saito,* and T. Mita*

All four sector magnets for the SSC have beenassembled in the cyclotron vault. Characteristics ofthe sector magnets and preliminary measurementsof the magnetic field made at the factory were described in previous reports. I) The four sector
magnets were installed during a period of MarchMay, 1984. Work on the electrical wiring as well as
cooling water connection was completed in July,
1984. Figure 1 shows a photograph of the sector
magnets in the cyclotron vault.
Power supplies for main and trim coils have been
installed and are now being tested. Table 1 lists the
specifications of the power supplies. A total of 67
power supplies are required to energize main andtrim coils for formation of the magnetic field distribution. These power supplies are grouped into
six types according to the way of connection between four sectors. All power supplies are housedin eleven cubicles. Two types of power supplies(M1 and M2) are used for main coils and fourtypes of power supplies (TA, TB, TC, andTD) are for trim coils to form various isochronous
field and harmonic fields. 2),3) Strict current stability
is required for M1 and M2 power supplies to obtaina high quality beam. The current sensing to achieve
such high stability is performed with a precision
shunt resistance made of germanium-manganese-

Fig. 1. Photograph of the sector magnets assembled in thecyclotron vault.

* Sumitomo Heavy Industries, Ltd.

copper alloy (ZERAMlN) with a temperature
coefficient less than 3 ppmtC between 15°C and
33°C. The shunt resistance is cooled by temperaturecontrolled water kept at 25°C±O.5°C. Both power
supplies have been inspected and tested. Current
stability of 5 X 10-6 for 24 hr was achieved at currents of 1,050 A and 600 A. Test of four types ofpower supplies for trim coils has almost been accomplished. Power supplies of TD type are now being adjusted to attain the specified current stability.
All the power supplies are controlled by the computer through the CAMAC modules named ClM

Table 1. Specifications of the power supplies for the main
and trim coils.
Type
Main coil
Ml
M 2-0

Max
current(A)

Bypasscurrent
(A)

1050
1050

l---A

Trim coil
330
TA 1
410
TA2
490
TA3
530
TA4
TA 5
560
230
TBI-0
1",4
420
TB2-0
1",4
TB3-0
530
1",8
TB4-0
550
1·..·--4
590
TB5-0
1",4
450
TC 1
500
TC 2-1,2*TD 1-1, 2
250*TD 2-11, 12, 13
14, 21, 22,400
31, 32, 33,
4.
*TD 3-11,
12, 21, 22,
550
23, 24, 31,
32, 33, 34,
35,36

Power
(kW)

Current
stability370
140

5 x 10- 6 /24 H
5 x 1O- s/24 H

4.7
7.8
24.7
17.9
18.3
2.2

1.5 x 10-5 /8 Ft-100

1.5 x 1O- 5 /8 H

-55
5.7
-50
32.3
-50
18.6
- 40
10.9
- 50
4.3
5.6
1.58

2.5 x 1O- 5 /8 H
5.0 x 10- 5 /8 H

18.6

42.7

* polarity of these power supplies can be changed.

171

S. Motonaga, et ai.

and used before for the field measurements. 5) Thissystem was controlled by DEC LSI-II micro computer with a CAMAC system. In October 1984, an
M60 super minicomputer h~s replaced the LSI-II
micro computer for control of the measuring systemand processing of the field data. An NMR gaussmeter (SENTEC) equipped with four NMR probes
and a multiplexer is introduced to this system.
Selection of the NMR probes and the search out ofan NMR signal are done by the CAMAC system.
NMR signal is also read out by the CAMAC system.
Calibration of the Hall elements is now being
made. Detailed measurements of the magnetic field
distribution are scheduled to start at the end of 1984
and will be carried out until fall of 1985.

and DIM (M60: M350-60/S00).4) Figure 2 shows aschematic diagram of control system of the power
supplies for the sector magnet. Information between
CIM and DIM is transmitted through optical fiberand Receiver/Transmitter provided for CIM and
DIM. DIM is set in each cubicle of the power
supply. Figure 3 shows a block diagram of a control
sequence of the power supplies and DIM. Four
input and output ports of DIM are connected
through optical elements to devices to be controlled.
Each power supply is provided with a 16 bits D /A
converter.
A field measuring system was already constructed

r;6Ol

~
References

I'--_ __ c_' A_H_AC Ser ia 1 High~ay

1)

Optical Fibers

2)
3)

12V Logic
1--~50p

Flat Cable

4)
InterlockL . . - - - - + + - - - - . f t - - - - - H - - - - - j Cross Connec t

BOX
Main
Coil

Main
Coil

Tri.

Trill

Coils

Coils

5)

Fig. 2. Schematic diagram of the computer-assisted control
system of power supplies.

I ,

DIM

S. Motonaga, H. Takebe, A. Goto, T. Wada, Y. Oikawa,1. Takeshita, Y. Ikegami, J. Abe, T. Tsukumo, H. Saito,
and T. Sato: RIKEN Aeeel. Progr. Rep., 16, 183 (1982);
Sci. Papers I. P. C. R., 77, 8 (1983).
S. Motonaga, H. Takebe, A. Goto, Y. Yano, T. Wada,and H. Kamitsubo: j. de Physique., CI 213 (1984).
A. Goto, H. Takebe, S. Motonaga, Y. Yano, N. Nakanishi, and T. Wada: Sci. Papers I. P. C. R., 77, 54(1983).
T. Wada, J. Fujita, K . Shimizu, r. Yokoyama, and T.
Kambara: RIKEN Aeeel. Progr. Rep., 17, 138 (1983);
K. Shimizu, ]. Fujita, T. Wada, and 1. Yokoyama: ibid.,
p. 141.
H. Takebe, 1. Takeshita, J. Fujita, T. Wada, r. Yokoyama, N. Nakanishi, S. Motonaga, and T. Sato: RIKEN
Acee!. Progr. Rep., 16, 188 (1982); Sci. Papers I. P. C.
R., 77, 20 (1983).

Power supply

I
I

I
I

TO

OlE

elM
E/O

to other UP/DOWN countersand polarity registers

32
Status date

Interlock~---~----------~~~~

Isolation amps.

Fig. 3.

Block diagram of a control sequence of power supplies and DIM.

Switchs

172
RIKEN Accel. Progr. Rep. 18 (1984)

Model Study of the RF Resonator for the RIKEN sse

V-3.

K. Ogiwara, T. Fujisawa, Y. Oikawa, and S. Kohara

Design study of a RF resonator for the RIKEN
sse was previously reported.1),2) It proved practicability of the movable box structure tuning
scheme in the frequency range from 17 to 45 MHz,but the voltage distribution along the dee gap was
found minimum at around 1/4 way of the dee radius
and the value at frequency 43 MHz was 80% of thevoltage at the injection radius (see Fig. 1 a); suchvoltage distribution was unsatisfactory for beam
quality.3) This distribution resulted from theresonator structure employing slanting stems toward
outer radius to reduce power consumption in thevicinity of the lowest frequency. A radially increasing voltage distribution desirable for good beam
quality is realized in a movable box resonator using
straight stemps positioned at an inner radius (seeFig. 1 b). Such modification, however brings un-

acceptable power loss at frequencies below 20 MHz.
As a compromise, we decided to employ a straightstem resonator and to discard a part of the frequency range below 20 MHz. In this case, the samerange of energy and nuclide is realized by extending
the harmonic number of acceleration in the sse to
10 or 11. 4)
The new resonator was designed and its performance was studied on a 1/4 scale model. Figure 2
shows a photograph of the new 1/4 scale model
resonator. In Fig. 3, Q values and positions of the
movable box deduced from the experimental results
are shown against the resonant frequency together
with the values calculated by the transmission line
approximation. The Q values are estimated bymultiplying the measured Q values by a scale factor

Q)

bD

2

"0
>

Frequency- 43MHz

2

Q)

>

.~

ro

Q)

0:::

3

5
9
7
Radial position

11 12
Fig. 2.

A photograph of the 1/4 scale model resonator.

Fig. 1 a. Example of relative dee voltage for the resonatorwith slanting stems.

I

15000

Q)
Q)

"0

Movable
box

0.6

x

10000

0
.0

Q)

Q)
0.4 :0

::l

ro

ro

>

,- - - '
Q)

00

3

>

0

0'

Dee

E

5000

0.2

2

(5

>

C!.)

2
O ., ~-

>

:;J

ro

Q)

0::

20

1
1

3

9
5
Radial position
71112

Fig. 1 b. Example of relative dee voltage for the resonatorwith straight stems.

E

.g

25

Position of
movable box
30 35 40
Frequency (MHz)

45

Q)

:5

....0
c
0

:;J

'u;
0

a..

Fig. 3. Q values and position of the movable boxes for theactual resonator estimated by the experimental results.
Solid lines show the calculated values by transmission line
approximation.

K. Ogiwara, et aZ.

173

2.68 meter

Accelerating gap

Frequency; 46.3MHz

4

---,

(J.)

B

45.0

tl.O

2

(5

>

3

(J.)
(J.)

"0

42.9

(J.)

>
+'
co

40.4

a;
a:::

2

35.4
27.8
21.6
1112
Extraction
Radial position
7

9

A

Fig. 4. Relative distributions of RF electric field along thedee gap. The frequency shown is 1/4 times of the measured
one.

o

400

Fig. 6.

~ 300
~

500S;

e

(J.)

o
s::

.g 200

400 ~

~
.~
.....
s::

300 ~

2

(J.)
(J.)

:J

t5 100

200
o

100

o~~~~

20

0

__ __ __~~

25 30 35 40
Frequency (MHz)~~45

Fig. 5. Shunt impedance (Rs) and estimated dee voltage(V dee) for the actual resonator estimated by the experimental
results. Open circles show the shunt impedance at extraction
radius.

v4ofand resonant frequencies by 1/4. The
resonant frequencies measured are reproduced
fairly well by calculations. The measured Q values
are 2/3 of the calculated ones. Relative distributionsof RF electric field along the dee gap were measured
by a perturbation method. 5) The results are shownin Fig. 4, where the dee voltages are normalized ata beam injection radius. The distributions are desirable more than those measured on the previous
model.
The shunt impedance was deduced from measurements of the dee voltage and the power loss. The

Cross-sectional view of the actual resonator.

dee voltage was measured with a calibrated voltage
pick-up which gave little effect on the resonator
characteristics. The power loss was obtained bymeasuring input RF current, voltage, and theirphase on the feeder. The shunt impedance of th~
actual resonator was estimated by multiplying themodel's value by the scale factor of vT. Figure
5 shows the shunt impedances and the dee voltage
estimated for input power of 250 kW.
The difference between the calculations and measurements in shunt impedance and Q value are notsmall. However, we consider such disagreements
are inevitable in the one-dimensional transmission
line approximation because the resonator has complex structure and resistances of many contacts are
neglected.
From the satisfactory results of the present model
test, we designed a new resonator shown in Fig. 6.
References
1)

K. Ogiwara, T. Fujisawa, and Y. Oikawa: RIKEN Accel.

Progr. Rep., 17, 145 (1983).
2)
3)
4)
5)

T. Fujisawa: ibid., 15, 196 (1981).
A. Goto, N. Nakanishi, and Y. Yano: 10th Int. Conf.
on Cyclotrons, p. 36 (1984).
H. Kamitsubo: ibid., p. 257 (1984).
L. C. Maier, Jr. and J. C. Slater: ]. Appl. Phys., 23, 68(1952).

174
RIKEN Accel. Progr. Rep. 18 (1984)

V-4.

RF Power Amplifier for the RIKEN sse

T. Fujisawa, S. Kohara, K. Ogiwara, and Y. Kumata*The power amplifier for the RIKEN SSC using
an RCA 4648 tetrode has been already designed. 1)
The amplifier will satisfy the required performance.
However, the amplifier was redesigned with following reasons. Recently we can obtain a new tube
RS2042SK whose maximum plate disipation is
300 kW. This tube is inexpensive and is quickly
obtainable compared with the 4648. Furthermore,engineers of the factory which is to fabricate theamplifier prefer to use the RS2042SK because it ismore convenient to use in a grounded grid configuration than the 4648 which is designed as a groundedcathode tube. The RS2042SK is lately developed by
SIEMENS. It has been used for a 300 kW middle
wave broadcast transmitter and also used as the laststage of the amplifier of the RFQ linac of GSI. Somepieces of RS2074SK which is a bigger sister tube of
RS2042SK are working well as amplifiers for theaccelerators at GSI and SIN.2) The final amplifier
was studied on a full-sized model with a real
RS2042SK.

Interelectrode capacitances of the RS2042SK
were measured and the results are listed in Table 1
together with·those given in a catalog. The amplifier
is designed based on the measured ones. Figure 1
shows a schematic drawing of the amplifier system.
The RS2042SK is used in a grounded grid configuration. The plate circuit is the same as that designed
for the 4648. 1) The cathode circuit is a quarter wave
length coaxialli!le having a variable tuning capacitor
Table 1. Interelectrode capacitances of RS2042SK tetrode(pF). CA.Gl, and CA . K were obtained by measuring voltage
transmission ratios from the plate to the grid and cathode.
The others were measured with a conventional LCR meter.
The information was given by Siemens.

C A .G2
CA .GlCA.K
CGl.G2CG2.K
CGl.K

Measured

Catalogue

Information

113.5
5.7
1.1
451.
37.5
315.

75.
5.
1.
450.
40.
280.

100.
4.5
1.1
442.
34.
318.

Plate stab

81D.1.2mt=====I_Movable short
Plate DC blocking
capacitor 2 350 pF
Resonator

Screen by passcapacitor 0.09 ,uF
Grid bypass
capacitor 0.115 ,uF' "'li-~~

All pass network

Plate DC
blocking
capacitor

7 4D, 0.6m
Cathode tuning
capacitor

Grid 1

Cathode tuning circuit. lOO - 600pF

I Screen~. bypas.s
capacitor

130
O.3m

CUI. k+ C UI, u2:::: 200pF

Fig. 1.

* Sumitomo Heavy Industries, Ltd.

Schematic drawing of the amplifier for the RIKEN SSC.

175

T. Fujisawa, et at.

Blocking capacitor
Equivalent 2 350 pF
circuit of
the plate of
RS 2042SK

1

Box

2125PF R~50{]

Zw= 130 Zw= 130
23cm 15cm
Zw=740 60c';'
I

I,

I

_

_ _ _ _ _ _ _ _ _ 4-

Tuningcapacitor

Equivalent circ~itof the cathode of
RS 2042SK

Equivalent circuit for the cathode circuit.

Equivalent circuit for the plate circuit.

Calculated value

2000

x
o

Calculated value
Measured value

1500

§
u:-

~
x

---- Rk=6.7 (0)- -, Rk = 8.3 (0)- - - Rk = 16.8 (0)Measured value0
Rk=6.7 (0)A
Rk= 8.3 (0)x.~ Rk= 16.3 (0)

~

Q)

0

u

c:
ro

E: 400

-0

II>

1000

~

U

c:

x·

.§

300

ro
a.
ro

U

_ _

100-600 pF

Fig. 3.

2
·0

::

I

rJ,latest'ub

0.05-1.2m

Fig. 2.

:

200

~

500

A

'?---- x

100

o~1~6~2~0--~2~5---3~0~-3~5~~40~~4~5--o~16~~2~0--~2~5~~3~0~-3~5~-4~0~~45~--

Frequency (MHz)Frequency (MHz)(a)

Fig. 4.

(b)Tuning characteristics (a) and input impedance of the cathode circuit (b).

(20 to 500 pF). This coaxial line also functions as afilament choke coil. The RS2042SK is driven by a
15 kW driver amplifier. The input circuit of thedriver consists of a pair of all pass networks similar
to the one developed by Mosko. 3 )An equivalent circuit of the plate tuning circuit isshown in Fig. 2. The performance of the same
circuit for the 4648 has been already presented. 1)
The tuning and matching characteristics were measured on the full-sized model with the real tube.
They are in good agreements with the calculations
with the equivalent circuit shown in Fig. 2. The
stroke of the movable shorting plate is estimated tobe 1.2 m to cover a frequency range of 17 to 45 MHz
and the range of capacitance of the impedance
matching capacitor (Cs ) is from 60 to 120 pF to
make the load resistance 200 Q.
The plate DC blocker is a cylindrical capacitor(35 cm height X 35 cm diameter: 2,350 pF) whose
insulator is made of Kapton film (125 pm X 16
turns). It was also installed on the model amplifier
and its frequency characteristic was measured at
frequencies from 17 to 150 MHz. No resonancecaused by the blocking capacitor was detected.

The cathode driving voltage was estimated to beabout 450 V to deliver the power of 300 kWand thecathode input impedance about 8 Q. Consequently,
driving power of 12 kW is required. The driver
tube RS2012CJ can deliver the power of 15 kW forload resistances from 500 to 1,500 Q, and its optimum load resistance is about 1,000 Q. The cathodeequivalent circuit is shown in Fig. 3. Tuning and
impedance matching conditions are investigated ona full sized model mounted on a model tube which
is a coaxial line as large as the real tube and has aresistance as a dummy of the cathode resistance.
The results are shown in Fig. 4. The lines in Fig.
4 show the calculations with the equivalent circuit
shown in Fig. 3. The calculations and measurements
are in fairly good agreements. The cathode input
resistance varies from about 6 to 15 Q dependingon the cathode RF and grid DC voltages. As you cansee in Fig. 4 (b), the input impedance of the cathodecircuit is between 500 and 1,600 Q for frequency
range of 17 to 45 MHz even if the cathode resistancechanges.
The control and screen grid bypass capacitors
have the same structure as shown in a previous

176

T. Fujisawa, et al.

report by the authors. 1) The full sized models were
fabricated and installed on the model amplifier withthe real. tube. The capacitance of the control grid
bypass is 115,000 pF and that of the screen 90,000
pF. The voltage transmission ratios from the plateto the grids and cathode were measured in a frequency range of 30 to 48 MHz. They showed almost
flat frequency dependence and are about 6 X 10-5
for the control grid, 1.2 X 10- 3 for the screen gridand 3 X 10- 3 for the cathode. These values are consistent with the interelectrode capacitances.
It was made sure on a model that the all pass
network for the input of the driver amplifier worked

well in a frequency range of 17 to 45 MHz.
References
1)

2)

3)

T. Fujisawa, S. Kohara, T. Ogiwara, Y. Oikawa, andY. Kumata: RIKEN Accel. Progr. Rep., 17, 148, 149(1983); S. Kohara, T. Fujisawa, and Y. Chiba: ibid., p.
152; T. Fujisawa, K. Ogiwara, S. Kohara, Y. Oikawa, I.
Yokoyama, M. Hara, I. Takeshita, and Y. Chiba: Proc.
10th Int. Conf. Cyclotron and their Appl. East Lansing,Michigan, U.S.A., p. 311 (1984).
G. Hutter: Contribution Paper to Particle Accel. Conf.
Santa Fe, New Mexico, U.S.A. (1983); Private communication by A. Nickel at Siemens.
S. W. Mosko: IEEE Trans. Nucl. Sci., NS-24 (3), 1786
(1977).

177
RIKEN Accel. Progr. Rep. 18 (1984)

V-5.

A Method of Measuring Two-Dimensional Motion of the Orbit Center
Using Three Radial Differential Probes
Y. Yano and A. Goto!

In the sse, radial differential probes are arranged
at three azimuths of sector-edge lines as shown in
Fig. 1. A method of measuring the position of theorbit center using these probes has been studied.
We define the valley mid-line and the dee midline as x- and y-axes, respectively. The condition for
the acceleration equilibrium orbit (AEO) was described in a previous paperl); this orbit is depicted
in Fig. 2. The radial gain Ar is the difference in radii
between the successive AEO's in one turn. The
angle a derived from the above condition is given by'. +(r- Ar)(2)!

Pe2= +(1+zt)(r+ Ar)!

'. +(r+ Ar)!

(4)'.+{r+(1+! if)Ar}(5)

Pe3= +(1+at)r·. +(r+ tjAr)
Pe4= - c1 (1 +at) (r+Ar)(1)

Pe5= +(1- at)(r+ ~ Ar)

where ro (radial displacement) and ro' (angle) represent the principal axes of the eigen-ellipse at theradius of r on the x-axis and l)r the corresponding
radial focusing frequency. From Fig. 2 the radii ofthe AEO at each azimuth of probe, P e1-Pe6 , aregiven by. +{r+( ~ - ! if)Ar}(6)

Pe6=+ (1 - at)(r+ ~ Ar)'. + (~ !

!

Pel=+(l+zt)(r- Ar)

{r+

-

y

--------~------+-~~----~h_------X

Fig. 1.

(3)

Arrangement of radial differential probes in the sse.

if)Ar}(7)

178

Y. Yano, et al.
yyProbe 1

Fig. 2. Acceleration equtilibrium orbit (AEO) and configuration of three radial differential probes. In case of our sse,

Fig. 3. Beam trajectory with respect to the AEO. The orbit
center exists at the coordinate of (Ax, Au).

a=20°.

(lZ)

where c=cos a, t=tan a,

and

f

1
( rr 0' )sin (7rVr/Z) r;;-

(8)

(13)

(9)

(14)

Because the value of z is negligible, it is taken to benull in Eqns. (Z) and (3). The term, (Jr)2, is also
neglected in Eqns. (4)-(7).
The beam trajectory with respect to the AEO isshown in Fig. 3 when the orbit center exists at thecoordinate of (Ax, Ay). We neglect the rotation of
the orbit center during about It turns. From Fig.
3 the radius (P1 ) of the position where the probe 1catches the beam is given by(15)
From Eqns. (Z)-(15) the following relations are
obtained.
1

Ax= 8 cos a (P6+3P5 - 3P4- P3)+-isina!(P6-P5+P4-Pa)

(16)

1
1
Ay=-Z . 1+ tana {ZAxtana(10)-cosa(P1+P2 -P3-P5)}(17)

In the same way,
Reference(11)

1)

Y. Yano, A. Goto, and N. Nakanishi: RIKEN Accel.
Progr. Rep., 15, 1SS (1981).

179

RIKEN Accel. Progr. Rep. 18 (1984)

V-6.

Acceleration of Off-Centered Beam in the RIKEN SSC
N. Nakanishi, A. Goto, and Y. Yano

For a beam which does not have enough turnspacing in the extraction region, we have some ways
to achieve single turn extraction. As one of them,acceleration of an off-centered beam has been examined. The turn separation of the off-centered
beam shows an oscillatory pattern because of rotation of the orbit center around the machine center.
The radial position of an off-centered particle isgiven by!)

2.0
r

1.5

u

~

a

1·9
0.5
0·.0
10.

;7.5
a:
0:::

Rn=Rc(n, 9'cp)=:5.• 00:::

+A cos {W 0-211:~: (lJr(R)-l)dn}

2.5

where Rc is the radial position at a turn number nof a well-centered particle with a central position
phase, 9'cp, and A the oscillation amplitude, W0 is
the betatron oscillation phase at an injection point,
and lJ r the radial focusing frequency.
In the above equation, the amplitude A is a function of the radial displacement and the angle of theoff-centered orbit with respect to the well-centeredorbit at the injection point. The integration term
depends on the acceleration voltage. Firstly, thevalues of the radial displacement and the angle weresearched to give as large oscillation amplitude as
possible under the restriction that the off-centered
beam clears all of obstacles like injection elements.
Secondly, the acceleration voltage was adjusted sothat the maximum turn separation and the optimum
angle of the beam can be obtained at the extraction
point.
Calculation was made for a proton beam of an injection emmitance of 20 mm·mrad. Initial energy

10.

d 7.5
w

~ 5.0
~

a

2.5

~

4.0

a

o

~

3.0

.......

=

w 2.0

Cl

1.0

o . 0 k+==~H==+::::::t=+=+:::::j:=+==t==+--!---l
80

120

160

200

240

'"o~

II)

=>
C>

352
353
354

a:

a::

...J

w
a::

351

-20

-10

o

320

360

spread and central position phase were set to be
zero. The vertical component of the rf magnetic

CJ

355

280

R (eM)
Fig. 1. Variation of beam properties in radial and longitudinal
phase spaces for a 9 MeV off-centered proton beam.

10

20

REL AZINTH(OEGI

Fig. 2. Radial phase space ellipses in the last five turns. Abscissa is a relative azimuth.
The 0 deg. corresponds to a valley center. Ordinate is the product of radius and cosineof a relative azimuth. Numerals at the left show turn numbers.

N. Nakanishi, et ai.

180

2.0

B 1.5
0::::

o

1.0

0.5
0.0~4--r-+--r-+-~-+~--+-1--r-+--r-4

10.
07.5
a:
0::::

:: 5.0
0::::

2.5

10.

0 7 .5w:: 5.0
e
o

2.5

~

4.0

o
o

o 3.0

w

field caused by voltage distribution along accelerating gap was taken into account using distribution
measured in a model cavity. Behavior of four parameters in the radial and longitudinal phase spaces isshown in Fig. 1 for the off-centered 9 MeV protonbeam. The difference between the well- and offcentered beams was found to be very sma'll exceptthat energy resolution degrades slightly in the offcentered case. In Fig. 2 are shown radial phase
ellipses in the last five turns at several azimuthal
positions at the extraction region.
The 10 MeV proton beam encounters a resonanceof radial focusing frequency J)r=4/3 at the energyof 188 MeV. It is known that this is a quadratic,
nonlinear, and intrinsic resonance. We confirmedthat its influence is negligibly small for the wellcentered beam. As seen in Fig. 3, on the other hand,
it is not so small for the off-centered beam. This isdue to the effective extension of a radial beam size.
Therefore, this method is not always suitable forthe 10 MeV proton beam.
There are many parameter sets to make extractionof the off-centered beam possible. We have to employ the parameter set which does not make beam
quality bad.

2.0

Reference

o

1 .0

1)

O.O~4--r-1--+-1--+~~+--r-+--r-+--r~

80

120

160

200

240
280
R (eM)

320

360

Fig. 3. Variation of beam property in radial and longitudinal
phase spaces for a 10 MeV off-centered proton beam. The
effect induced by a resonance lJr=4/3 is observed.

W. M. Schulte: The Theory of Accelerated Particles in
AVF Cyclotrons, thesis, Eindhoven University of Technology (1978).

181

RIKEN Accel. Progr. Rep. 18 (1984)

V-7.

Beam Sharing System for RIKEN sse

K. Hatanaka, T. Inamura, Y. Yano, K. Yamaguchi, and H. Kamitsubo

The RIKEN heavy-ion linac (RILAC), which is
to be used as an injector to the separated-sector
cyclotron (SSC), will also supply beams for theexperiments using RILAC itself at the same time
when SSC is in operation. For such beam sharing
between SSC and the experiments using RILAC,a pulsed deflection magnet with a fast rise- and falltime is designed.
Figure 1 shows the plan view of the beam transport system from RILAC to SSC. A pulsed deflection magnet (DALO) is introduced to deflect beams
by an angle of 5.73 0. The bending radius is 3 m andthe maximum field is 0.26 T. The pole gap is 4 cm,
which is sufficiently large compared with the verticalbeam size in the magnet. The coil is wound of copper hollow conductor having a cross section of
8.5 X 8.5 mm 2 with a hole of 4 mm in diameter; thetotal number of windings is 16. The magnet will be
excited with a pulse mode of a rise- and fall-timeof 1 ms and a flat-top of longer than 10 ms. Designed
values of electrical characteristics are listed inTable 1.
The system consisting of two dipole magnets(DML1 and DML2) and quadrupole magnets(QDL11, QSL12, and QDL13) is a beam shifting
section. Beams are achromatized after passing
through this system. Four quadrupole magnets(QSJ24-QSJ27) are introduced for matching beamemittance to a succeeding system. 'A beam pulsing system by a sinusoidal wave, apulsed beam chopper, and a mechanical beam

chopper are planned to be installed on the beam line
as shown in Fig. 1 (SPX22, SPX23, and MCX23).
They are useful in obtaining a pulsed beam for TOF
or life-time measurements.
An ion-optical calculation of the beam transportsystem was performed on the basis of the following
specifications: (1) maximum magnetic rigidity, Bp,
is 0.785 T'm for 238U40+ at 0.84 MeVJu after passing
through a charge stripper; (2) emittance in thetransverse phase space is 61r mm·mrad at maximum;(3) energy resolution, .dE/E, is better than 0.15 010
at FWHM; and (4) the RF phase width of the beamphase is less than 6°. Beam envelopes throughout
the system in the on- and off-midplanes are shownin Fig. 2.
The plan view of the beam handling system leading beams to the experimental areas from SSC isshown in Fig. 3. A numerical calculation of ion
optics was reported previously. The system provides
the following beam preparation modes: (1) achromatic, double-telescopic transport to every target
Table 1. Designed values of electrical characteristics of apulsed magnet to share the beam from RILAC.
Maximum current
ResistanceInductanceDirect voltage
L dI
dt
Power

RILAC

#6

/---t---+==---- - -- - - - - to RILAC experimental areastank(unit: em)

Fig. 1.

Plan view of the beam transport system from RILAC to the slit SLJ27.

520 A
5.9 mQ
0.48 mH
3.1 V
250 V

1.6kW

182

K. Hatanaka, et al.

-6.
DRIFT

-5.

-3.

-I.

-2:

O.

0.20 "

DURO.

0.20 "

DRIFT

4.92 "

2.

3.

'.

5.

6. eM -6.
0.00 "

J

DRIFT

-3 .

- 5.

- 2.

-I.

O.

" RGNET

0.30 M

DRI fT

1. 30 M

2.

I.

3.

4.

I 1

0. 20 M

5.

6 . eM0 . 00 M§ DALOI \0.20 M
0.50 M

CD ::rJ
rr1

n

rr1"RGNET
DftlfT

!
,
,

,
,,
,,
,

~ DMLl.D.35 M
1.07

n

DURO .

0.20 M

aURO .

0.20 M

DRIFT

0.78 MI~ ODX23

4.73 M~ ODX 2 3

5.04 "
5 . 2. "DURO .

0.20 M

DRIFT

0 . 65 M

DURO .

0.20 M

aURO.

0.20 M

DRIFT

1.0 7 "MAGNET

0.36 M

DRIfT

0 . 90 "

..l

t

\

/

\\/ \//
,)

I
I

\

,

\
I

I

[:. QDLll

3.53 MOC

3. 73 M

0",.
00

0.20 M

DRIfT• 3 . 02 M

\.

o

:;:'?

~ QDL 35.36 M03:

t:: QDLlJ

5.67 Mco

VJ ",.
O-<II~ D~IL2

6.9. M
M

3:
3:

I
\
I

,

)
\

\

0.3. "DURO .

0 . 20 "DRIfT

0.3. "DURO .

0.20 M

DAIFT

0.34 "

DuRO.

0 . 20 M

DRIfT

0 . 60 "

EXIT

I
I

I

X
.\
\

\:
"-

~ QS J2 5

10.70M

I:: QSJ26

11.2.M1./'

10 . 90M

Joo~ QSJ27

\11

::0
CJ

-u
II

1\\.

o
I
\

I

\
\

I

I

I

11.7BM

DURO.

0. 20 M

11 . 9BM

DuRO.

0.20 M.II

DRIFT

0.50 M

I

1\,

,
,
I

12.5BMIEXIT~ QDX22

II. 73M

F:::'"nDX22

12.04"
12.2' MII.

12 . 74 M

Fig. 2. Beam envelopes through the system from RILAC to the slit SLJ27. Solid anddashed curves show beam envelopes in the on- and off-midplanes, respectively.

from RILAC

D

Fig. 3.

't~ TSiS

TSiA\

TS40
Lab.4

Lab.3

Lab.2

II

o

\

I

11.44M

-<

::!

\

I
J
I
J

o

8 .72 M,,:

10.36M

I

I

M

I

I O. 16M~ QSJ24

XI.
:1
I

B. 52 M

1\ 1//

,
,,

I

B.21

~ QDL21I\

0 .20 "~ QDL21

I

\

DuRO.

o

\

I

\

(\J

o

7.31

Lab.!

Plan view of the beam handling system for SSC experimental area.

rr1

0<::::l: .......
::rJC

'0

I

'1

M

M

II

I

0.20 MDURO .

+

Q

4 . 71

" II

DURO.

::!
::!
•

' . 51

5.B7 M

,/ \

rr1
::rJ

(\J

I
I

V
V
I\
I

(J)

-u

3.22 M~ OSL 2

/

\I

I

-u

~ QDLllI//\ /~\\

,

o

x-<
II -<

\

I

CD
rr1
:D

<

r::!

::rJ

"

"

z

rr1

rr1

/

1

I .

!
I

I. BO M
2 .1 5 M

\

I
I
J
I

DRIFT

~

IJ r
::!J)

/,

J

DURO.

I .•

~

'.73 "

K. Hatanaka, et al.

Table 2. Designed values of electrical characteristics of a
26.5° bending magnet.
Maximum current
ResistanceInductanceDirect voltage

500 A
60 mO
160 mH
30 V

L.!R

160 V

dt
Power

15 kW

area except for Lab 1 ; (2) double-dispersive, doubletelescopic transport with a momentum resolution
up to 25,000 in Labs 2, 3, and 6; and (3) isochronoustransport to Labs 4 and 6. A crossed-beam experiment can be performed at the target station TS7A.
Sometimes it will be beneficial for two experimental groups to share the beam. For this purpose,
every 90° bending magnet is divided into two pieces
as shown in Fig. 3, one of which deflects the beamby 26.5° and the other by 63.5°. It has been con-183

firmed by an ion-optical calculation that the beam
conditions obtained from the previous analysis l ) with
90° bending magnets is reproduced satisfactorily by
this modified configuration. The dipole magnet
which deflects the beam by 26.5° will be operated
in a pulse mode, and more than two experimentalgroups can share the beam. The pole gap is 6 cm.
The coil is wound of copper hollow conductor having a cross section of 13 X 13 mm2 with a hole of 6
mm in diameter. The total number of windings is128. It takes 1 s to reach the flat-top and also 1 s tofall down to zero field. The beam is shut off during
these transient periods. The flat-top duration will
be adjusted according to requirements from experiments. The designed electrical characteristics arelisted in Table 2.
Reference
1)

T. Inamura, N. Kishida, Y. Hata, and H. Kamitsubo: Sci.
Papers 1. P. C. R., 77, 96 (1983).

184

RIKEN Accel. Progr. Rep. 18 (1984)v-so

Design of Beam Buncher in the sse Injection BeamTransport Line
A. Goto, T. Fujisawa, and I. Takeshita

The beam transport line from the RILAC to the
SSC has a length of as long as 65 m. Therefore, abeam buncher is indispensable to make beam timefocused at the injection point of the SSC. It was
decided from ion-optical calculations that thebuncher is placed 37m downstream from the
RILAC. The buncher reduces the pulse width of abeam, for example, from ± 6° in rf phase at the exitof the RILAC to ±3.6° at the injection point of theSSC. Calculations showed that a total voltage required for bunching is 160 kV at the maximum.
The buncher was designed to work with as low
power losses as possible and have as small a size as
possible. For that purpose, a second harmonic modewith respect to the frequency of RILAC/SSC rf
system (20-45 MHz) was adopted. Maximum peakvoltage per gap and the separation of gaps can be
reduced by a factor of two by this adoption. Furthermore, multi-gap system was taken for further
reduction of required voltage. Characteristics of thebuncher thus determined are as follows:
Frequency range
40-90 MHz
Harmonics
2
N umber of gaps
4
Maximum peak voltage per gap
20 kV
Width of each gap
20 mm
Separation of gaps
156 mmAperture of beam transmission
30 mm
Figure 1 shows the schematic drawing of thedesigned resonator. The resonator is of a )./4
coaxial type with a movable shorting plate. In Fig.
2 are shown the tuning characteristics, current
density at the movable shorting plate, and total
power losses that were calculated by using thetransmission line approximation. The maximum
power loss was estimated to be smaller than 500
W. Current density is kept less than 20 A/cm. A
sliding contact for the shorting plate will necessitate

Voltage pickup

Sl iding
contact
Outer
conductor
Inner conductor

Fig. 1.
100

Schematic drawing of a model buncher.

Eu

VOEE = 20 kV"~

c = 12 pF
Zo= 86 n

1.0

~
Vl
Vl

E
0.5 lii
:;:

o
a.

ro

~
0~0----~5~O~O----~1~O~OO~--~1~50~O O
S(mm)

Fig. 2. Calculation of electrical characteristics of a model
buncher. Parameter S is a distance between the shorting
plate and the neck of the outer conductor as shown in Fig. 1.

no special technique. Stroke of the shorting plate
is about 1 m.
A model of the buncher is now under fabrication
to verify the calculation. Detailed design of thebuncher and the selection of a wide-band power
amplifier will be made after the measurement ofelectrical characteristics of the model.

185
RIKEN Accel. Progr. Rep. 18 (1984)

V-9.

Control System of the RIKEN SSC

T. Wada, J. Fujita, K. Shimizu, 1. Yokoyama,
T. Kambara, and H. Kamitsubo
RIKEN SSC is controlled with a computer system. The control system consists of a computer network and a CAMAC serial loop. Micro processors
are used for the interface between devices and the
CAMAC system.
Figure 1 shows the network system. Three minicomputers are linked by using duplex optical fiber
cables at a transmission rate of 15.36 Mbps. Each

computer is of the same type, and is MELCOM
350-60/500 (M 60). The characteristics of thiscomputer and the configuration of peripheral devices
were reported previously. 1) One of the three computers was installed in the SSC vault in August,1984. A CAMAC serial highway driver (SHD) was
installed in November. Figure 2 is the photographof this computer and Fig. 3 show,s the configuration.

ConsoleRadiation monitor

Fig. 1.

Network system.

Fig. 2. Photograph of the present MELCOM 350-60/500
computer.

IFA: Integrated File Adapter
SEL:Selector Channel
CLA :Coaaunication
Linkage Adap"ter
MPX: Multiplexer Channel
ISC: Intelligent Systea Console
FDD: Flexible Disk
SHD:Serial Highway Driver
UPA: Undefined Port Adapter

SHD
UPA
5Hbps
CAHAC

CRATE

U
P

C
C

A

L

2

Fig. 3.

Configuration of the present computer system.

186

T. Wada, et at.

Two disk units are supplied, which are of a fixedhead type because of reliability. As was mentioned
previously,l) the operating system 0860/UMX is acombination of real time and UNIX systems. Oneof the two disk units stores 0860 files and the other
UNIX files. The color graphic CRT is used for the
display of magnetic field distribution, beam profiles,
etc. The color character CRT is used for the displayof synoptic diagrams of various systems. Four T8S
terminals can be used in a UNIX system for program development. One of them (#1) can also be
used in an 0860 system. The line printer can printout capital and small letters because the small letters
are frequently used in the UNIX system. A micro
computer L8I -11/02 is linked to the M60 computerby an R8-232C cable at a transmission rate of 9,600
bps. The programs and data are transmitted using
this link. Five CIM's and fifteen DIM's is fabricated 2) in October, 1984. Each DIM are installed ineach box of the power supply for the main and trim
coils.
This computer system has been working wellwithout trouble during four months. The development of many application programs and data basefor the control are in progress in the UNIX system.
The UNIX system is very convenient for the program development. The developed programs aretransfered to 0860 files and are tested in real time
operation. A disadvantage of this dual operating
system may be the fact that we must remember two
kinds of operational commands. The programs of
micro processors in CIM and DIM are developed
using a micro processor developing system.
The magnetic field measurement will start in
December, 1984. The programs for the measurement in the LSI-It computer which were used in
19823) are converted to the M60 computer. Almost
all devices are controlled through the CAMAC
system. A digital volt meter and a scanner whichmeasure the voltages of HALL probes have to belinked to a computer by GP-IB. A GP-IB moduleof CAMAC is developed 4) because the installationof GP-IB interface of M60 is scheduled in October,
1985.
References
1)

2)
3)

4)

T. Wada, J. Fujita, K. Shimizu, I. Yokoyama, and T.
Kambara: 5th Symposium on Accelerator Science andTechnology, Tsukuba, Japan (1984).
K. Shimizu, M. Nagase, and I. Takeshita: ibid.
H. Takebe, I. Takeshita, J. Fujita, I. Yokoyama, T.
Wada, S. Motonaga, and T . Sato: RIKEN Accel. Progr.
Rep., 16, 188 (1982).
J. Fujita: p. 187 in this report.

187

RIKEN Aeeel. Progr. Rep. 18 (1984)

V-10.

An Intelligent CAMAC GP-IB Controller Module

J. Fujita
A CAMAC module with intelligence and GP-IB
function is developed and its outlines are described.
(1) Purpose
The main purpose is to decrease overhead of ahost computer on short protocols repeated frequently during message and data communicationfrom GP-IB devices. The module is designed basedon the following requisites. A large quantity of data
can be transfered rapidly at a time. The module
receives messages or character strings from thehost, translates them, executes a sere is of GP-IB
functions and stores data generated by devices on
a GP-IB bus without intervention of the host.
(2) Hardware
A block diagram of the module is shown in Fig. 1.
The circuit consists of three portions. The first is abasic and intelligent portion which forms a single
microcomputer board. It consists of a MC6800
microprocessor, two PROMs (4 KB+4 KB), two
RAMs (2 KB + 8 KB), a MC6850 serial port, anda MC6821 parallel port. One of PROMs is for amonitor software and another is dedicated for GPIB functions. A small RAM is used as a working
area of the monitor and a large one for temporarystorage of collected data on the GP-IB bus and at
the same time for loading test programs. The
MC6850 port is connected to ' a cassette taperecorder and used for loading and saving test programs. The M C6821 port is used for a console of/the microcomputer.
The second is a portion of the GP-IB interface
which consists of a TEXAS INSTRUMENTS
TMS9914A GP-IB adapter chip supported by thegreater part of IEEE488 GP-IB standard and two
GP-IB bus interface IC chips. The TMS9914A
chip selected by an address decoder circuit on the
microprocessor bus behaves as a bus controller on
the instrument bus.
The third is a portion of the interface with a
CAMAC dataway and storage of data collected on
the instrument bus. Here are two memories of 768
and 12 K bytes both of which are composed of six
IC chips. They are accessed in an 8 bits byte mode
from the microcomputer and in a 24 hits word mode
from the CAMAC dataway side. They are continuously addressed in the dataway, but not in the
microcomputer since there is no memory range
corresponding to its addressed signals (address lines
A1= 1, AO= 1). A routine of software solves periodical absence of the address and can virtually continue
address manipulation on sacrifice of their accesstime.
(3) Software
The host computer can check the states of twomemories by reading half-byte status information
through READ lines on the dataway. The last threebytes of the 12 KB memory give error conditions
occuring at statement syntax or handshake on the
GP-IB bus and count number of collected data in

fl, L, I
N
Fl - F16
A1 - A8
S1,S2,Z

Decoder&_Timinggenerator

CPU
Timing pulses.

MC6800
RAM

PROM

>.

!----- !-----

(IJ

::
2

2KB+8KB

4KB + 4KB

(IJ

0
()

W1 - W24

~

<2::

(,)

MemoryBus<2::

BufferI---

f---------

Buffer

R1 - R24

GP- IB
Adapter TMS9914A

768+12K
bytes
AlA
MC6850V
Fig.!.

r----- r-----PIA
MC 6821Block diagram of an intelligent CAMAC GP-IB controller.

Bus
Interface188

J. Fujita

sixteen bits binary number.
The host computer writes a message of an ASCII
string with hexadecimal codes into a 768 bytes
memory. The message is a chain of statements which
begin with one of the following six alphabets, T, I,
D, W, R, and B, accompanied by definite codes
and ASCII data after them and end with a colon.
These alphabets show abbreviated commands inthe microcomputer.
Statements have the following formats and meanings. A small letter n is an integer value from 1 to255.
shows n times repetition of the stateTn (.. .):ment within brackets.
delay time intervals of n X 0.1 sec.
Dn:resets the TMS9914A chip and theI:
GP-IB bus.
Wn " ... ": writes ASCII data enclosed byquotation marks to a device numbern on the bus.
Rn:reads data from the device number
n into the module.
Bn " ... ":is a concatenation of Wand R or
equivalent to a statement Wn " ... ":Rn:.
A message from CAMAC dataway is executed
while being resolved into any of above statements inthe same manner as a BASIC interpreter. If a
statement begins with a character other than above
six ones or is told in a false format, error flag is set atbit-O of error status Ihyte mentioned above. Timeout error on the GP-IB handshake is also indicatedby bit-lor bit-2 of the same byte. When a R or B
statement is executed, collected data count number
is set in binary number at two bytes succeeding to
the error status byte.

(4) Test results
Tests are performed by using a DEC LSI-11
microcomputer and a Perkin Elmer 3220 minicomputer. The GP-IB module is connected to two
GP-IB instruments, a 2204A scanner and a 8502A
digital voltmeter of FLUKE. Messages and data
are delivered correctly between the 3220 minicomputer and the module in a Stop or Repeat mode ofblock transfer modes described in the IEEE standard583.
For example, following messages are transmitted
from the LSI -11 to the module where decimal
numbers after T, B, D, and Ware given in hexadecimal codes. Device addresses of the scanner andthe digital voltmeter are 3 and 1, respectively.
1) I: B1 "VR": W3 "0,":2) T20 (B1 "?": W3 "+": D 10:):
The first statement sets the digital voltmeter tothe measurement of DC voltage in an auto-range
mode and the scanner at a channel number O. The
next one causes the voltmeter to measure a voltage
of an object and transmit the reading data of afourteen byte size into the module through the GPIB adapter, and then the scanner to advance one
channel and the module to wait for a second. The
sequence is repeated twenty times and data of total
280 bytes are stored in the 8 KB memory.
The module works properly, but the following
points should be improved in hardware and software. They are (1) to add a LAM circuit to the
CAMAC interface portion in order to report Message Accepted or Data Ready states of the memories
to the host computer and (2) to use an interrupt
line of the M C6800 microprocessor and make known
Message Ready or Da~a Accepted states of thememories, and (3) to develop a software extended
by those processes.

189

RIKEN Accel. Progr. Rep. 18 (1984)

V-11.

Method of Sealing Vacuum Chambers and Pumping Control
System for the SSC
K. Ikegami, S. Nakajima, Y. Oikawa, and S. H. Be

The final design of the vacuum chamberl) was
fixed and the chambers are now under fabrication ina factory. A vacuum test for four magnet chambers
will be done in September, 1985. Design of thepumping control system for the SSC is in progress.
In January, 1984, a method of sealing by using apneumatic expansion seal 2) for the chambers waschanged to that by using a side flange with a welded
bellows. The welded bellows is shaped like a racetrack and its size is about 3,000 X 30 mm. Figure 1
shows a cross sectional view of the side flange withwelded bellows between the magnet chamber andthe RF chamber. The side flange with the welded
bellows is fixed to the magnet chamber and ispressed with bolts tightly to the RF chamber. A
similar method is also employed between the magnet
chamber and the valley chamber.
The magent chamber is surrounded with additional chambers in which pole pieces made of mild

MAGNET VAe, CHAMBER

RF VAC. CHAf1BER

RF CAVITY
COPPER

steel and trim coils flash-coated with a thin alumina
layer are placed, because of a high outgassing rate
expected from them. The additional chamber ispartitioned by a thin stainless-steel plate of 4 mm inthickness from the high vacuum chamber and isevacuated to a pressure below 10-1 Torr. Thispartition wall may be deformed when the pressure
difference between the additional chamber and thehigh vacuum chamber becomes higher than one
tenth of atmospheric pressure and collapsed perfectly under atmospheric pressure. To prevent thepartition wall from collapse a safety valve to be
mounted between two chambers was developed.
Figure 2 shows a model of the safety valve. The
characteristics of this valve are shown in Fig. 3.
A moving plate of the valve is pressed to a valve
seat by a weight in the moving housing. An operating pressure difference is determined by a numberof the weights put in the moving housing. Thus, thevalve begins to operate above the pressure differencein the range of 8-50 Torr.
Control of pumping system
The pumping system described in a previous
RIKEN Accel. Report 3) is operated automaticallywith a programable controller which is made by
SUMITOMO SCC-1000 having an I/O port ofmax. 1,024 points according to a predetermined

ADDITIONAL VAC. CHMiBER

HIGH VAC. CHAMBER

ADDITONAL CHAMBER

DEE

Fig. 1. Sealing method which uses the side flange with welded
bellows between magnet and RF chamber.

Fig. 2. Sketch of a model of the weight loaded safety valve
equipped between high vacuum chamber and the additional
chamber. The valve seat is pressed by the weight in the moving housing; elasticity of the welded bellows does not play
an essential role, because the elastic strength is usually
decreased slightly with time.

190

K. Ikegami, et al.

60

50
cc:
cc:

0
I-

BELLOWS: 210~ (OD)40

160~ (ID)

W
u
2:

lLI

cc:

lLI
U.
U.

30

Q

lLI

cc:
=>
(I)

20

(I)

lLI

cc:

0..
l!>

:z:

10

;::
~

UJ

0..
0

0

5

10

15

20

WEIGHT IN THE MOVING HOUSING (Kg)

Fig. 3.

The characteristics of the safety valve.

?

VACUUM CHAMBER OF THE SSC
PG

GAUGE HEADS
WATER

0 OPEG 0 IG

CRYO PUMPS AND
CRYO PANELSTURBOHOLECULARPUMPS----------IMULTIPLEXE

1

1---------ROTARY PUMPS AND
MECHA. BOOS. PUMPCOMPRESSED AIRTEMPERATURE
MEASUREMENT--------LEAK VALVES AND

AIR OPER. VALVESI.

~

HANDLING
BOARD

1

l

I
I

: ANALYSERI

ISOLATION AMP.

).

1

~

7

PROGRAMMABLE~

I IONIZATIONlQUADRUPOLE: GAUGESl MASS: PENNING
1 AND
I PlRANIGAUGESI

I.

GRAPHICQMA HEADS

1-----------

CONTROLLER

A

...
A

~

U

I

DIM ( DEVICE

1

INTERFACE MODULE)

y

I

I
A

I

.... I...";:.
TO THE CONTROL CONSOLEI THROUG H THE CIM
TilE CYCLOTRON VAULT

Fig. 4.

Block diagram of the pumping control system for the sse.

sequence. The following conditions are included inprograming of the controller.
(1) Evacuation from atmospheric pressure to (pressures of the order of) 10-8 Torr.
(2) Protection of the chamber and pumps fromvacuum failure and electrical failure.
(3) Stopping the pumping system and admitting
dry N2 gas into the chamber from (pressures ofthe order of) 10-8 Torr to the atmosphericpressure.
(4) Regeneration of cryopumps and cryopanels.
Figure 4 shows a block diagram of the pumping
control system. On the graphic handling board

which is placed in the cyclotron vault, both mannual
and automatic operation is possible.
For the automatic operation of the pumping system, vacuum gauges such as Pi rani gauges (32 gauge
heads), Penning gauges (8 gauge heads), and ionization gauges (4 gauge heads) are planned to be used
for the system. In addition, for observation ofresidual gases in the vacuum chamber and detectionof leaks from gasket seals, and welded parts, and soon of the chamber, a quadrupole mass analyzer
having four heads through multiplexer is equippedto each RF and valley chamber. Information of thepumping system is sent through DIM (Device

K. Ikegami, et al.

Interface Module)4) and CIM (CAMAC Interface
Module) to the central control console.

3)

References

4)

1)
2)

K. Ikegami, S. Nakajima, Y. Oikawa, and I. Takeshita:
RlKEN Accel. Progr. Rep., 15, 200 (1981).
K. Ikegami, S. Nakajima, Y. Oikawa, S. Motonaga, and191
H. Kamitsubo: Sci. Papers 1. P. C. R., 77, 87 (1982) . .
K. Ikegami, S. Nakajima, S. H. Be, I. Takeshita, Y.
Oikawa, and S. Motonaga: RlKEN Accel. Progr. Rep.,
17, 156 (1983).
K. Shimizu, T. Wada, J. Fujita, and 1. Yokoyama: Proc.
Int. Conf. Cyclotron and Their Application, Michigan(1984).

192
RIKEN Accel. Progr. Rep. 18 (1984)

V-12.

Performance Test in Cryopump

S. Nakajima, K. Ikegami, Y. Oikawa, and S. H. Be
As a main vacuum pump for the sse vacuum
chamber, a cryopump with a large pumping speed
and large refrigeration capacity may be useful. The
cryopump which functions by condensation andadsorption of gas on the cold panel cooled at about
10 K can evacuate virtually all kinds of gas to theultra high vacuum region. We plan to use ten cryopumps with a pumping speed of 104 1jsec (N2) and
four cryopanels of 5 X 103 1jsec (N2) for obtaining
ultimate pressure of 10-8 Torr in the sse vacuum
chamber. In this report, we present preliminary
experimental results on the characteristics of the
cryopump with a special emphasis on regenerationof low temperature cryopanel coated with activatedcharcoal. The regeneration interval depends on thepumping capacity for hydrogen molecules anddecides the operational interval of the sse.
Tests were carried out with a 4x 103 l/sec (N2)
ANELVA cryopump. Figure 1 shows time-dependent variation of temperature and pressure for the
cryopump. Temperature was measured on thesecond stage cryopanel with a Iplatinum resistancethermometer and pressure was measured at an inletof the cryopump with an ionization gauge. The
panel temperature reaches 70 K for 65 min and 10
K for 80 min. Final pressure in each test run seems
to vary owing to the previous history of the vacuum
system. Generally, the time required to reach 10- 6
Torr is about 100 min, namely after about 20 min
the cryopanel was completely cooled down. Figure

2 shows temperature rise of the cryopanel andpressure rise in the chamber as a function of time.
As seen from Fig. 2, the temperature rises rapidly
at first and then slowly to reach room temperature.
As the temperature of the cryopanel rises, the pressure begins to rise at first and then drops. Soon it
rises again but drops after a while. It rises once more
and finally reaches an almost saturated value after
about 15 hr. A partial pressure was measured at thesame time with a quadrupole mass analyzer(Q.M.A.). The result is shown in Fig. 3. From these
two results, we conclude that the first peak is due tohydrogen and the second due to nitrogen. The peakabove 160 K is due mainly to water.
A comparative study was made on regenerationof the cryopump by admitting dry nitrogen gas into
the pump; the results are shown in Fig. 4. The
purge of the chamber was done after shut down of
the pump. As seen from Fig. 4, the time required forregeneration of the cryopump is shortened by gas
purge. The quantity of absorbed water on the innerwall of the chamber is also reduced by purging.
Thus, it makes evacuation easier.
Pumping speeds for hydrogen and nitrogen werealso measured. The results are shown in Fig. 5.
The obtained value is about 2.3 X 103 1jsec for

<1>

10°F
V)

"0
C

o

U

<1>

V)

<1>

~

'0
~

~

<tI

~

E
<1>

o

I-

Time (minutes)

Fig. 1. Time dependent variation of temperature and pressure for the cryopump.

o

I

I

I

5

10

15

RegeneJation time (hours)

Fig. 2. Temperature rise of the cryopanel as a function oftime and a pressure rise in the chamber after the refrigerator
was switched off.

S. Nakajima, et al.

ISj\

H2

6

ff

10- 9

0)

I

(>

£

,

o

4-,
"

tlO

c:

ff

:0

~

I

\

I

~

f

J

I

'6SK

VI

~ 2000 r-

'is.

E

I

•

10-4

10-5

P.-4_~-~~ 2S00-0Cl>

g. 2400

I

tlO

10-11~~~~~~~~~~L-~~-L~

300

360

Regeneration time (minutes)

Fig. 3.

:~10- 6

Pressure (Torr)

15SK
240

-

:J

c..

'4,~
/" l

l

f

2400 r-

0.

X

l..\

I

~
]

I

~~

\1"

co

& 10-10

x"

"

,,~

I

I

el 2 SOO I-

I" "'.-x"x""",".....b"

I

u

H20
2S-

193

c
.~ 2000
:J

c..

10-16

Partial pr ~ssure curves during regeneration.

Pressure (Torr)~

Fig. S. Pumping speeds for hydrogen gas and nitrogen gas
measured at several equilibrium pressures.

300

2VI

-

-0
C

o

u

.....
"Cl> "-

200

-0
.~~

0)

:5

-

Cl> '"
1.co..........
.....
'--'
co

0 ----..

0)::':::::3:;;. 0.0.
~ fii

100

at this point"

E0O)i::'

~

10

0

el

Admit N2 (760 Torr) at this point

u

o

10
5
Elapsed time (hours)

5

0.

~

E

VI
VI

0.

:J :J

~")(,,

~ 0)

c..:S

0

"X

")(f"x " "",,)(
40

200. r. . ·

xX

x)(

)(

SO

120

SO

120

Time (hours)-

Fig. 4 : Comparison between the experiments for regeneration of the cryopump with and without admitting dry
nitrogen gas into the pump.

either case. Since a cryosorption capacity of charcoal
for hydrogen is considered to affect the regenerationof the cryopump, hydrogen gas was admitted into
the pump at a constant flow rate and the variation ofpumping speed was observed. This result is shownin Fig. 6, which indicates that the pumping speed
began to decrease and the pressure began to increase
after about 66 hr. The total hydrogen admitted for
66 hr is estimated to be 2.7x 103 Torr·[, whichmeans that a pumping capacity for hydrogen gas iso40Time (hours)

Fig. 6. Variation of pumping speed and pressure with time
when hydrogen gas was admitted at a constant flow rate.

40 Torr'[ per l ·g charcoal. No trouble was observedin the Cryopump during 4,000 hi- operation at 10-8
Torr.

194

RIKEN Accel. Progr. Rep. 18 (1984)

V-13.

Calculation for the Design of a Beam Dump
N. Nakanishi, T. Shikata, S. Fujita, and T. Kosako*

In a previous report, 1) the design of a beam dump
was made rather roughly, because cross section data
were not available in the energy range appropriate
to the RIKEN sse at that time. Recently theneutron-photon multigroup cross section in an
ANISN format for neutron energies from thermal
to 400 MeV has become available, and the calculation using the ANISN code has been made to obtain
diagrams which are used for determination of theconfiguration of beam dumps.
Neutrons to be shielded are assumed to be generated by reactions of (1) 200 MeV protons with athick aluminum target and (2) 135 MeV/u carbon
ions with a thick iron target. In both cases the beam
intensity is assumed to be 6 X 1012 ions/sec as before. 2) These reactions are abbreviated as (p+AI)
and (C+Fe), respectively.
To begin with, we calculated the dose attenuationand the energy spectra of neutrons for several shielding materials. Considering these results, we took
several kinds of beam dumps composed of different
materials and carried out the transport calculation.
The most desirable structure has been proved to bea shell structure of iron surrounded by a heavy
concrete layer.
The design calculation of the beam dump in a
forward direction relative to ion beams was performed using the (p+AI) source and those for otherdirections were carried out using the (C+ F e) source,

because the (p+AI) source has more pronounced
forward -peaking characteristics than the (C + Fe)
source. An essential part of the cyclotron building
and allowable dose rates around the beam dump areshown in Fig. 1.
Geometries employed in the calculation and theresults are shown in Figs. 2-5. For the forward
direction, if the beam dump is designed so as to

RFE
+oJ

C

'0

0. lO-1

10
+oJ

10
Q)

eel 10-

2

o

C

10-3

II : Iron
III : Heavy concrete
IV : Concrete( P + AI) 0'- 30',lO-4 1

2

3

Radius of a beam dump,R1 (m)(a)
B (O.6mrem/ h). . . . ...

: '.

"

", ,',',',',~ , ' . ' ,' ":',''. ''-

,

:::

R::
t
ro

0.1.0
c

,~

D

Beam direction
E, , ,,' ' ,', , ' , E ~-:, -,-----:-...,.--,, '. ' . '".,', " ::J r ' ...;..,_. _ ' --,---,-_'...;...-....:.JC
E, .. ~ ' : (2 m rem/ h) ~.~ 0,5'6roc::Radius of a beam dump,R 1 (m)
.

,

....

Fig. 1. A longitudinal sectional view of the building arounda beam dump and allowable dose rates at several points.

* Research Center for Nuclear Science and Technology,
The University of Tokyo.

C10.....o(b)

Fig. 2. Result of the design calculation for the forward
direction: (a) Geometry employed in the calculation using
ANISN code, and the dose rate at a point A' as a functionof the radius of the beam dump (sum of radial thickness ofiron and heavy concrete parts). (b) Effect of thickness of eachcomponent of the iron-heavy concrete beam dump.

N . Nakanishi, et ai.

195

10 3

10 3

10 2
:2
'-..
E
~

g

co
.....
c

~ .. .

.....ro~Y . - P+O<>o.~ 10 0C,,)..... 10 1

c
'0

c.

,2

ro

~lO-1

'

1_ : ...1

I : Voiden~• -1>~

c~

ro
+'

ro

2

~

'd

I'J)

o

'10- 2

en

0

0

~Q.>

II : Iron
III : Heavy concrete
IV: Void

10 0

Q)(radius= 5Cm)~-sc QSi

o

'Z

10-1

III : Heavy concrete
IV : Concrete

V : Concrete

V: Void(C+Fe) 60·-1,20·

VI: Concrete

10-3 0~·~--~~~~0~.-5~--~~~~1.0'Radius of an iron sphere RFE Cm)

Thickness' of an iron part,RFE (m)

(a)

E

I

~0.8
ro

c.

2 0 .6
~

g 0.5
o
o

>,0.4

>
ro

~0.3

ro

'0 0 .2
en

~0.1

~

o

:c

I-

I 0.8 r----r----,---r--r--r---r-.----r--..--.

I

~

R:;

t:TO.7(a)\~. ~, \~%

, \\\ .\\
~

\

\

,

\

\

Q;:

tt
0.7
ro
c.

0.6

e§ 0.5Q)o>, 0.4
>
ro

~ 0.3
!!l

'0 0.2
VI

I

0.5

1.0
Radi'us of an iron sphere,RFE (m)

VI

Q)

c

~

0

:c
I-

0.1
0.5

1.0

'f.5

Thicknes of an iron part,RFE (m)(b)
Fig. 3. Result for the upward direction. (a) Geometry anddose rate at a point B. (b) Effect of thickness.

(b)
Fig. 4. Result for the downward direction. (a) Geometry anddose rate at a point C. (b) Effect of thickness.

suppress the dose rate at A' below the allowablelevel, the dose rate at A will be safely below thetolerance level. The calculated result is shown in
Fig. 2 (a). The dose rate at the surface of the outermost concrete shell is given as a function of theradius of the beam dump (sum of radial thicknessesof iron and heavy concrete parts). Figure 2 (a) is
also expressed like Fig. 2 (b). One can choose anarbitrary combination of each thickness of iron andheavy-concrete parts at a given dose rate. Similarly,
geometries employed in the calculation and theresults for different directions are shown in Figs.

3-5. The relation shown in Fig. 4 is also useful forthe design of sideward shielding. In the design forthe backward direction, if the dose at the surface ofthe beam dump is less than about 3 rem/h, neutron
doses in neighboring rooms will be safely below thetolerance level. There exists, however, a problem tominimize the leakage neutrons through the entranceof the beam dump not only for health hazard but also
for radiation background in experimental equipments. This problem is to be solved in the near
future together with those of the activation and theheat generation in the beam dump.

N. Nakanishi, et al.

196

References
1)
10 10

2)

10 8
:2
-........
E

10 6

~

E

120"-180"

10 4

2

~

Q)
U)

I : Void (radius = 5cm)
II : Iron

10 2

0

·0

10°
10- 2

RFE= 0.8m'-RFE= l.lm

10- 4

o

2

4

t

R4

Radius of a beam dump

6

8

(m)

Fig. 5. Dose attenuation by transport calculation of neutrons
upon passage through an iron-heavy concrete beam dump in
the backward direction.

T. Shikata, T. Kosako, S. Fujita, S. Yamaji, and H.
Kamitsubo: Sci. Papers I. P. C. R., 77, 99 (1982).
S. Fujita, S. Yamaji, and T. Shikata: IPCR Cyclotron
Progr. Rep., 14, 203 (1980).

197
RIKEN Accel. Progr. Rep. 18 (1984)

V-14.

Beam Attenuation Device

Y. Miyazawa, M. Hemmi, T. Chiba, and M. Kase

The new beam attenuation device, installed in abeam line between the linac and injector, is capableof controlling beam intensity onto a target over awide range by a ratio between 1 t010-4. Figure 1
shows inside structure of the device. Three attenuation plates (attenuator) are mounted on three of fourholes in a disk made of chrome-copper alloy. Since
the disk itself is made to form a gear wheel, theattenuation plates can be correctly positioned by a
motor via a rack and pinion. Two such disks areused in tandem to obtain large change in attenuation
ratio specified above. The size of device was reduced
by use of a magnetic fluid vacuum seal between thedisks in a vacuum and the motor in atomosphere.
The disk rotates at about 1/3 rps. As shown in Fig.
2, the attenuator plate has a lot of small holes perforated by chemical etching. In the table below
Fig. 2, 1> is a diameter of small hole, p is a distance
between small holes in mm, and n is the ratio of thearea of the plate to the perforated area which defines
the attenuation power of the plate. Table 1 shows
the beam attenuation ratios for various combinationsof the two attenuators. Heat generated by beam loss
in the attenuator is removed into air by conduction
through the disk and vacuum flange made of cromecopper alloy having a good heat conductivity. The
disk driving circuitl ) is shown in Fig. 3. The angular
position of the disk is converted into electric signal
voltage by use of a multi-turn potentiometer, andits signal is fed to a window comparator (I C102)

through a buffer-amplifier with a low-pass filter.
The position signal is compared with the reference
signal by the comparator. Four reference voltages

40

Type

r/J

p

n

A
0
E

0.5
0.1
0.1
0.1
0.1

0.66
0.19
0.42
0.61
0.89

2.2
4.6
22
47
100

Fig. 2.

Parameters of the attenuator.

8

C

Table 1. Beam attenuation ratio for various combination of
the positions of the two disks.
Position of disk I

Position of
disk II

rAJ

2(D)
3(E)

0

leD)

2(C)

3(E)"

0
2.2
47
100

4.7
10
220
470

22
48
1,000
2,200

100
220
4,700
10,000The words in the brackets present a type of attenuator.

Fig. 1. A beam attenuation device. 1, Attenuation plate; 2, First disk; 3, Disk shaft (copper);4, Second disk; 5, Synchronous motor (60 rpm); 6, Magnetic fluid vacuum seal; 7, Multi-turnpotentiometer; 8, Vacuum flange (chrome-copper alloy).

Y. Miyazawa, et ai.

198

Ref
+lOV
8.5V

I C103

Rys

(l)I~

FWD

I.:.:.J

~

(2)
I~ I

(3) '" REV

Moter

53

100V
0.14 A60 rpmrWo~M'.-+-'WA-~"rt 6.2 5VVR• f
I C102.103 : Window comparator

Fig. 3.

+ 10V

Disk driving circuit.

given by Stef correspond to the four angular position of the disk. When the switch is turned on, thesynchronous motor drives the disks automaticallyand stops when the voltage of the potentiometercoincides with the reference voltage. The accuracy insetting the disk can be made higher by choosing anarrower voltage window for comparison. But
if the window voltage is made too small, the disk
runs over the narrow width of the reference position
because of its mechanical inertia, and begins tooscillate back and forth around the specified posi-tion. Therefore, the synchronous motor having asmall inertia was used in order to reduce the overshooting of the disk. At present, the setting accuracyof the disks at four reference points is less than±
1 mm giving a large margin to make the beam go
through the two successive holes without hitting theattenuator holders.
Reference
1)

M. Hemmi: Wheel driving circuit, private communication.

199
RIKEN Accel. Progr. Rep. 18 (1984)

V-15.

Emittance Monitor

M. Kase, I. Takeshita, and I. Yokoyama

A prototype of the emittance measuring device,
which will be used in the SSC injection beam transport line, has been built and installed in the RILAC
beam line.
The measurement method is the same as that
described in Ref. 1. The device is composed of two
main sections: the detector and the actuator.
The detector has a slit and a multi-wire profile
monitor. The specifications of the detector is listed
in Table 1. The thirty-two gold-plated tungsten
wires of the profile monitor are fixed on the Macor
mount with melted glass. Figure 1 shows a photograph of the profile monitor.
The actuator supports the detector and moves it
by a stroke of 100 mm with a 1.8 0 stepping motor andball screw. The position of an origin is detected bya photo-switch. The relative position from the origin
is measured by counting the signals from a rotary
pulse encoder. The resolution of position is 0.02
Table 1.

The technical specifications of the detecting system.

Slit

Width
LengthMaterial

0.1 mmMaterial of wire
Material of insulator
Number of wires
Diameter of wire
Length of sensitive region
Pitch of wires

gold-plated tungsten
Macor
32
0.1 mm35 mm
0.35 mm

ProfilemonitorDistance between slit and detector
Angular range
Angular resolution

mm and the position reproducibility is less than
0.1 mm.
A pair of emittance measuring devices are installed
in a vacuum chamber, one is set horizontally andused for the measurement of horizontal emittanceand the other is set vertically and used for that ofvertical emittance. Figures 2 and 3 show the photo-

30mm
molybdenum

Fig. 2.

Photograph of the emittance measuring device.

300mm±18 mrad±1.2 mradFig. 1. Photograph ofthe multi-wire profile monitor. Thirtytwo tungsten wires are strung on the insulator mount.

Fig. 3. Full view of the emittance monitor installed at the
RILAC beam line.

200

M. Kase, et al.

Start
~

Sending the data
to the central computer
Searching the origin

!

Movin
to
Start
point

Measuring

Finishl

Returning

o

53

(sec)

Waiting (35ms)

Moving to
the positionm

320 ms

650 msScanning
32 signals(step m)Moving to thepositionm+1

Scanning
Step)( m+ 110ms

nnE
r----1

1 ILSwitching to (n + l)ch.
LsamPling the n ch. signal
Switching from (n-1) ch. to n ch.

Fig. 4.

Time chart of the emittance measuring processes.

graphs of the device.
The electronic control circuit IS fundamentallythe same as that in Ref. 1. Unlike the previous
circuit two 16-ch multiplexers with MOS analogue
switches are used for scanning the 32 input signals
directly from wires. The leak current of the switch
is less than 0.1 nA. The sampling time has to bedelayed by 10 ms after switching to a new channel inorder to damp a switching noise current. Therefore
the time required for scanning the whole channels
is 320 ms. It takes 33 s to obtain the one-axis emittance data after making a "start" command at theconsole in the control desk. Further 20 s is needed
for the detector to return to the stand-by position.
The time chart of all the processes of the emittancemeasurement is shown in Fig. 4.
When the dc amplifier is inserted in the input
stage of the multiplexer for each channel and the
low current signals are converted to voltage signals,
the scanning time of the multiplexer for the 32 ch
signals can be reduced to 30 ms. Furthermore if theposition setting within 0.05 mm is allowed, thespeed of the actuator can be set at a higher rate.
Finally the time required to get the emittance datafor one axis after the start command is expected to
be as short as 15 s.
Reference
1)

I. Yokoyama, M. Kase, and T. Kambara: RIKEN Accel.
Progr. Rep., 15, 141 (1981).

201

RIKEN Accel. Progr. Rep. 18 (1984)

V-16.

Charge Exchange Technique In the Linac
M. Yanokura

It is well known that the charge states of highenergy heavy ions are varied by passing the ionsthrough thin foil or gas stripper. By use of thisphenomenon, we can obtain ions in various charge
states; this is an useful technique in atomic physics. I ) We plan to apply the technique to the linac
operation in order to obtain ions of higher charge
states and to save power consumption of the linac
as well.
The linac functions as a velocity filter. At a fixed
acceleration frequency, the velocity of an accelerated
ion is not dependent on its charge state, but theaccelerating voltage is in inverse ratio to the charge
state when an ion is specified. It means that, if we
accelerate ions in the higher charge states, we canuse lower voltage and save RF power for acceleration.
The linac composed of six resonators has many
beam diagnosis boxes which are set at every interresonator position and downstream of the No. 6
resonator. By use of those boxes a stripper can be
set at any position and ions are stripped at various
energies. We choose thin carbon-foil of 10 flg/cm 2
as a stripping material. A simple foil changer which
fit in the beam diagnosis box was fabricated at themachine shop of the institute; a sketch of the foilchanger is shown in Fig. 1. A maximum foil diameter is 20 mm and 3 foils can be set on it. The
position of the foil is adjustable by using a bellow
and a screw mechanism. Results of the test operation
using this device are shown below.
Ar 4+ ions were accelerated to 42 MeV by using
No. 1-4 resonators and were passed through carbon-

Fig. 1.

foil. A lower part of Fig. 2 shows charge distributionof Ar ions thus obtained. Analysis was made by usinga switching (SW) magnet. The most probable charge
state of Ar ions measured is 12+ at 42 MeV. An
upper part of Fig. 2 shows the same charge distribution, when the RF power was fed into the No.5
resonator and tuned for acceleration of 12+. Ar 12 +ions were accelerated to 50.6 MeV. This energy wasmeasured by the analyzing magnet which is set
downstream of the SW magnet. Acceleration voltage
of No.5 resonator was nearly 1/3 of that for Ar 4+
acceleration. Some of other charge state ions werealso accelerated by No.5 resonator, but the energy
gain per charge for those ions was less than thatof Ar 12 + ions.
Figure 3 shows another charge distribution spectrum of Ar ions measured under following conditions. RF power was fed into all resonators except
No.6, and the stripper was set between No.2 andNo.3 resonators. Energy of Ar beam at the stripper
was about 22 MeV, and the most probable charge
state of the outcoming ions is Ar lO+.2) In subsequent
acceleration, only 10+ ion was accelerated efficiently,
because a long accelerating path functions as avelocity selector. We obtained a 51 MeV Ar10 +beam of 20 neA, when Ar 4 + ions of 200 neA were
injected into the linac. About 40/0 of the injected Ar
particles were accelerated in this operation. On theother hand, total electric power consumption was
about 20% of that for Ar 4 + acceleration without
stripping. The charge stripping technique is useful
to save electric power though tuning of the linac
becomes complex little bit.

Simple foil changer.

M. Yanokura

20210n.---------------------------------~

10.-----._----~._------._--~

+

('t')

.....
+
.....

~

S
tl
c

~::s

b
.....

+
r-....

u

E
ro

l.n

&N
N

(0
N

Q)

CO

tl
c

~ 10

::s
u

SW magnet current

+

E

('t')

ro

......

Q)

Fig. 4 .

CDo+......
+

o::t......
+

O"l

25

30

35

SW magnet currents (A)Fig. 2. Acceleration of Ar 12 + to 50.6 MeV by the linac.
40 MeV Ar 4 + passed through carbon-foil and changed its
charge state from 4 + to 12 +. The abscissa is excitation
current of the SW magnet.

100.-------------------------,

10+

~

S

10
tl
c

~
::s
u

E
ro

Q)

CD

1

Charge distribution of 108 MeV Xe ions.

Finally, Fig. 4 shows charge distribution of Xeions, when 108 MeV Xe9 + ions were passed througha carbon foil; many charge states from 23 + to 31 +were formed. The stripper was set between No.6
resonator and the SW magnet. Xe ions were notaccelerated after stripping.
Charge stripping at the upstream positions ismore favorable than at the downstream positions
for saving power. However, subsequent tuning of thelinac takes more time when the stripper is set upstream position. A best position must be determinedby weighing those factors. Continuous use for about
20 days did not cause radiation damage of the foil.
The longevity of the foil may be due to following
two reasons. One is that energy of ions are rather
high and, therefore, its energy loss in the foil isvery small, 0.5 MeV for 40 MeV Ar. The other isthat the beam shape of the linac is adjusted to about
10 mm square at the stripper; therefore the energy
loss is spread in a wider area than for the strippers
in the terminal of a tandem Van de Graaff accelerator. The resulting little energy transfer provides
little damage for the foil.
References

SW magnet current
Fig. 3. Acceleration of Ar 10 + to 51 MeV. 20 MeV Ar 4 +changed its charge state to 10+ by a foil stripper.

1)
2)

Y. Baudinet-Robinet: Phys. Rev. A, 26, 62 (1982).
T. Tonuma: J. Phys. B: Atomic Molecular Phys-ics,
17, 317 (1984).

203

RIKEN Accel. Progr. Rep. 18 (1984)

V-17.

Design of a Rebuncher in RILAC
M. Kase and M. Odera

Figure 1 shows the calculations of longitudinal
phase oscillation at RILAC from the buncher in
the injection beam line to the final resonator tank(cavity #6). All the parameters affecting these oscillations are set according to the synchronous condition around -25 deg. The buncher rf voltage isCavity #1,.--A----,

00
Q)~ -/n ~==~=-~~
Q)

VI

ro

.c

a.

Time (in units of T12)

Fig. 1. Calculation of the longitudinal phase traces in RILAC. The vertical axis is a phaseon rf voltage and horizontal one is time expressed in units of TI2 (T is period of rf) andt = 0 when beam reaches at the first gap of the first resonator tanle The curves represent
the phase history of particles injected at phases from -130 to 130 with 5 deg. steps into
the buncher.
Rebun cher

~ l ~

#5

#6

00
Q)
"0

:-20 ~1-=~~~~~~~
VI

ro

.c

a.

61 72

86 94 105 114 123 130 139

Time (in units of T12)

Fig. 2. Calculation of the longitudinal phase trace when a rebuncher is used between thecavities #1 and #2. Other conditions are the same as in Fig. 1.

204

M. Kase, et al.

Table 1. Comparison of calculated beam qualities between
cases in Fig. 1 (case I) and Fig. 2 (case II).

Energy spread (fwhm)
Phase spread (fwhm)(at the exit of cavity #6)
Phase acceptanceCase I

Case II

1.9%

0.7 %

25 deg.

5 deg.

57%

61 %selected so that the phase acceptance is maximized.
As seen in Fig. 1, the phase oscillation becomeslarger and larger in the later portion of the linac
and no phase compression can be seen. These results are attributed to the effects of phase divergencein the drift spaces between the cavities, especiallybetween cavities # 1 and #2 and between cavities#3 and #4. The beam quality will be bad at the exitof the final cavity.
One method to damp the phase oscillation is to use
a rebuncher in a proper section. Figure 2 shows thelongitudinal phase oscillation when the second
harmonic buncher is inserted between cavities #1
and #2. The rf voltage of the rebuncher is selected
so that the energy spread at the exit of the final tankis minimized. Other conditions are the same as
in Fig. 1. Obviously the phase compression can beseen compared with the case in Fig. 1. Table 1

Table 2.

Specifications of the rebuncher.

Type
Frequency range
Maximum peak voltage per gap

2-gap buncher

34-90 MHz
70kVshows that some improvements in beam qualities
can be expected by using the rebuncher.
Since the space between the cavities # 1 and #2
has been occupied fully by a couple of quadrupole
magnets, two gate valves, and a universal beamdiagnosis vacuum box, the rebuncher should becompact enough to be installed in the beam diagnosis box.
As a resonant element of the rebuncher, we chosea quarter-wave coaxial type cavity with a drift tube
attached at the open end of its center conductor.
Second harmonic frequency of the rf used in the
linac was chosen as its resonant frequency to makeits drift tube length as short as a port of the vacuumbox (10 cm). The use of high frequency is also
effective to reduce the rf voltage.
The specifications of the rebuncher are listed inTable 2. It is being fabricated and its characteristics
will be measured soon.

205
RIKEN Accel. Progr. Rep. 18 (1984)

V-1B.

Production of Highly Charged Ions by Whistler
Heating of Plasmas
S. Ishii, H. Amemiya, Y. Sakamoto, and M. Yanokura

In a previous report l ) we presented a design ofa hexapole plasma source for studying the production of highly charged ions. Plasma heating is .indispensable for obtaining them. We had proposed theplasma heating by whistler wave because it canpenetrate dense plasmas without being cut off. The
whistler frequency was chosen 2.45 G Hz and thetarget plasma was produced by ECR discharge at afrequency of 9 GHz.
Construction of the hexapole plasma source wascompleted this year. The hexapole coil consists ofsix straight bars parallel to the magnetic axis of themirror field. Each bar is a bundle of six conductors
arranged in wedge shape and their effective center
is 0.103 m apart from the magnetic axis. We measured a magnetic configuration. The direction andstrength of the hexapole field are dependent on theradial and azimuthal coordinates. Near the axis
(R,........,O), however, the absolute value is almost
independent of the azimuth angle and rises qua~dratic with R. Figure 1 shows the radial distributionof the absolute values of the hexapole field. The
measured values are in excellent agreement withthe calculated ones. At a hexapole coil current Ih of
4,800 A the ECR field for a frequency of 2.45 GHz
exists within the plasma vessel, the diameter ofwhich is 0.106 m.
When the mirror field is superposed on the hexa-t---+--->o<- ECR field for 9 GHz

0.3

1m = 250 A.~:E 0.1z (m)Fig. 2. Axial distribution of the mirror field at a coil currentof 250 A and the ECR zone for a frequency of 2.45 GHz
when the hexapole field shown in Fig. 1 is superposed. The
solid curve shows the calculated mirror field and x represents
plots of the measured values. The dashed curve shows ageometrical shape of the ECR zone for zero electron
temperature. The dotted curves show the Doppler shiftedzone for Te = 10 eV and ne=l X 1018 m- a•
B (T)
0.1

0.11

0.09

V
~

<;7

I-

L

/

i

;

25

©/j
/.

//
/ /
/ i

20

'3

;

11

u

I

I

a.
0)(

I

I

0.1

~

/

5

/

~

ClI

-' I

I

~

/

:---t---;/
}~

,II

10

I

Qi
(5

,'/

I

R

0.08

30

15
0.2

0.2

I.

"/
/

/!
/

I

I

/

Ih =4800 A

ClI

:r:

0.8

0.9

1.0

1.1

W/Wc

0.1
Radius (m)Fig. 1. Radial distributions of the hexapole field at a coilcurrent of 4,800 A. The inserted sketch illustrates the endview of the hexapole coil and describes the related polar coordinate (R, 0). The solid and dashed curves show thehexapole fields calculated at 0 = 0° and 30°, respectively. The
measured values are plotted by x at 0=0° and. at 0=30°.

Fig. 3. Dispersion relations of the whistler wave. The solidand dashed curves show, respectively, real and imaginary 'parts of the wave numbers at various electron densities: <D
ne= 1016 m- a, (2) 1017 , ® 1018 , @ 1019 • The electron
temperature Te is fixed at 10 eV. The dotted curves denote
the wave numbers for zero temperature. w/2;r; is fixed at 2.45
GHz and the magnetic field is varied. The abscissa indicatesthe normalized frequency which is inversely proportional tothe magnetic field B. The ordinate means the wave number
normalized with the wave number in vacuum.

206

S. Ishii, et al.

pole field, the resonance zone forms an oval surface.
In Fig. 2 is shown the calculated resonance zone
(dashed curve) together with the axial distributionof the mirror field. Its dimension is 0.38 m in lengthand 0.08 m in diameter. This can be varied by changing the coil currents and the mirror spacing.
This resonance zone, however is valid for zero
electron temperature. Taking into account finite
temperature we calculated the dispersion relations
for the whistler. The space-time variation is taken
as exp[i(hz-wt)]. The relevant design parameters
suffice the regime of spatial growth,2) in which
w is real. The imaginary part of the wave number
h gives the spatial growth rate. The calculated wave
numbers for various electron densities ne are shownin Fig. 3 as a function of the magnetic field B near
ECR. The wave frequency w/2n: is fixed throughout
at 2.45 GHz. For the cold plasmas the resonance(k ---+ 00) takes place at W=Wc and k;. (the imaginary
part of k) is non-zero, where Wc is the electron
cyclotron angular frequency. When w<w c , however, hi is equal to O. This means that the wave
energy is absorbed only on the infinitesimally thinsurface shown in Fig. 2 (dashed curve). For thewarm plasmas, on the other hand, hr (the real partof h) is deformed (solid curves in Fig. 3) and hi issubstantially large over a broad range of B (dashedcurves in Fig. 3). This arises from the Doppler
broadening due to the finite temperature. The
chain curve in Fig. 3 denotes the Doppler shift.
It is noteworthy that this shift becomes large withincreasing ne' Thus the wave energy can be absorbed in the thickened zone indicated by dottedcurves in Fig. 2.
The critical density beyond which the ordinary
wave is cut off is equal to 7 X 1016 m-3 in the present
case. It is clear from Fig. 3 that the whistler has nosuch a limit and in addition the absorption of the
wave energy increases as ne rises.
Thus we are confident that the whistler is in favorof heating the overdense plasmas.
References
1)
2)

S. Ishii, Y. Sakamoto, and M. Yanokura: RIKEN Accel.
Progr. Rep., 17, 177 (1983).
L. S. Hall and J. E. Scharer: Phys. Fluids, 16, 2352
(1973).

207

RIKEN Accel. Progr. Rep. 18 (1984)

V-19.

Construction of ECR2

M. Yanokura, S. Ishii, Y. Sakamoto, and M. Odera

We reported outlines of two stage ECR ion source(ECR2)1) which has two cavities. In the first cavity,
dense plasma of low charge state ions is formed by
the Whistler mode heating. The plasma then diffuses
into the second cavity through a narrow orifice.
Highly charged ions are expected to be formed byfurther heating under a high vacuum by microwave
at the second cavity. This year, we have added somemodification in design of the ECR2. Most of thecomponents were completed and construction of
ECR2 was started.
In the previous design!) the use of aluminum
was planned as construction material of the second
cavity, however, some problems were found in theuse of aluminum. In the second cavity, it was
designed to set six pieces of permanent magnets
around an axis of the cavity to form hexapole magnetic field. Although positions of the magnets must
be adjustable to obtain desirable field distribution,
it was found difficult to build such a position adjustment mechanism in an aluminum vessel. Wechanged material for the second cavity from aluminum to stainless steel. By this change, cooling of thesecond cavity became much more difficult, because
heat conductivity of stainless steel is smaller thanthat of aluminum. Therefore we set longer coolingpipe around the second cavity to improve heatremoval.
Magnetic field distribution produced by threesolenoid coils is shown in Fig. 1. This magnetic field
distribution satisfies conditions for ECR and also
Whistler mode heating. For the Whistler mode excitation, microwave power is injected axially througha helix antenna into the first cavity from the position
where the magnetic field strength is higher than thatof the ECR resonance. A mirror ratio for the second
cavity is about 1.69, which is nearly equal to that ofan old single stage ECR source (ECR 1).2) Hexapole
magnetic field, formed by a samarium-cobalt permanent magnet, is added only to the mirror fieldof the second cavity. Further microwave power is
injected radially into the second cavity at the valleyof the mirror field.
On completion, the ECR 2 will be set on the highvoltage terminal of the linac injector. Therefore,
power consumption for the ECR 2 must conformto limitation of electric power supply for the terminal. The ECR 2 requires extraction high voltage,

2.45 GHz microwave, and magnet power supplies.
A PI G ion source installed on the terminal has amagnet power supply of 50 V and 150 A; We
decided to use this power supply for the ECR 2either and designed three solenoid coils. Eachsolenoid coil consists of a pair of tape-coils and astainless steel disk which was set between the tapecoils. These coils are cooled with the disk which has
coolant channels and is pressed tightly to an end
surface of the tape-coils. A size of copper conductor
is 65 mm in width and 0.8 mm in thickness. No.1,
No.2, and No.3 solenoid coils consist of a pair of110, 110, and 140 turn coils, respectively. Total
impedance of the three solenoid coils is about 200 mQ
as shown in Fig. 1. Positions of the first and second
cavities in the mirror field are also shown in Fig. 1.
A magnet excitation current of 120 A forms an ECRzone inside each cavity. This year, we could construct only a No. 3 coil and, therefore, we had to use
the solenoid coils of the ECR 1 for the No.1 andNo.2 coils tentatively though the inner diameter ofthe coils is smaller than an outer diameter of a metalseal flange which is to be used for the second cavity.
Therefore we use tentatively an elastomer-sealed
flange of which diameter is smaller than that of ametal-seal flange. After construction of the newNo.1 and No.2 solenoid coils, we shall change theflange to the metal-seal one.
A new type 2.45 G Hz oscillator using a magnetron-tube was manufactured. Its maximum output
power is 1.3 kW (CW); a block diagram of its
electric circuit is shown in Fig. 2. This oscillator
has two features different from commercial oscillator using a magnetron-tube. One is that theoscillator works in a complete CW mode by using athree phase rectification and smoothing circuit anda ripple in the output is less than 30 % , whereas
most oscillators using a magnetron-tube, which arecalled CW, work really intermittently. In order toobtain highly charged ions, the CW mode of heating
is essential, because tightly bound electrons are
stripped off from the ions in the step by step process
which takes time. Secondly, this oscillator has anamplitude modulation circuit and the modulation
frequency is adjustable in a range from SO to 120
kHz. The 2.45 GHz oscillator with amplitude
modulation was chosen because some instabilities
which are produced in the over dense plasma

208

M. Yanokura, et al.

L1

L2

hO. lOt>

No.3 coil.~ 0.05

c
ro

bJ)

~

No.1

No.2 llO T

140 T

1\11 1\112l00~ ~.-----:0:+--,~~ ~5 ~ ~ ~2~ ~5 r~~8~ ~ ~Hexa pole magnet'°0L-~~~--~----~----~80~~~nT--20~40---r60
Whistler mode cavity
Second cavity
Position (cm)Fig. 1. Magnetic field distribution of ECR2 formed by threesolenoid coils. Dots and dashes lines indicate an ECR zone
for 2.45 GHz.

formed by the Whistler mode excitation and cause
trouble are suppressed by modulation of the microwave at a suitable frequency. 3) Such a modulation
technique is difficult to be applied to usual highfrequency oscillator using a magnetron-tube. A
special design was tried, however, to take advantageof the high efficiency and low cost of magnetrontubes.
A new type vacuum window made for 2.45 G Hz
microwave is used at a port of the second cavity.
However, we had to solve some problems. One waspower loss due to window materials. If the power
loss becomes excessive, the window will be eventually broken. The other was a reflection on thewindow. Thus, we choose ceramic for windowmaterial. A 4 mm thick ceramic disk metallized atits edge was set inside a short cylindrical wave
guide by welding. Heat expansion of the ceramic
window is absorbed by deformation of the thin

Fig. 2. Block diagram of the 100 kHz modulated 2.45 GHz
oscillator using a magnetron-tube.

wall of cylindrical wave guide made of copper.
This window is cooled by air blow. Reflection of
microwave power on the window was minimized
by adjusting the position of the ceramic window
and varying a length of the cylindrical wave guide.
After optimization, the voltage standing wave ratio(VSWR) was found to be 1.045 for 2.45 GHz, which
is a very good VSWR value for a vacuum tightwindow.
Main components of the ECR 2 were completed
at the end of October, 1984. Assembling and tuningof the magnetic field distribution of the ECR 2
were started in November.
References
1)
2)
3)

M. Yanokura, S. Ishii, Y. Sakamoto, and M. Odera:
RlKEN Accel. Prog. Rep., 17, 175 (1983).
M. Yanokura and M. Odera: ibid., 15, 137 (1981),
Y. Sakamoto: Jpn. J. Appl. Phys., 16, 1011 (1977).

209
RIKEN Accel. Progr. Rep. 18 (1984)

V-20.

Automatic Control of a Gas Circulation and Gas-Feed
System for the Ion Source
K. Ikegami, T. Noda, N. Kamiyama, T. Watanabe, and I. Kohno

The gas circulation system and gas-feed system
for the ion source of the 160 em cyclotron were
newly developed and installed in the control room
in January, 1984. These systems are operated automatically according to the sequence predeterminedby a programmable controller which consists of an
OMRON SYSMAC MSR having an I/O port ofmax. 256 points.
1) Gas Circulation System
The high priced gases, such as 3He, enriched
13C02 , and 15N2 , necessitate the use of a circulation
system to recover a part of gases not accelerated ortrapped in the cyclotron. The system purifies thegases for reuse in the ion source. Figure 1 shows a
block diagram of the gas circulation and the gas-feedsystem for the ion source. The system consists of avacuum-tight intake and exhaust rotary pump

(RP2) for circulation, a first charcoal trap (Tl),second two charcoal traps (T2 and T3), two reservoirs (one is for the 3Re gas and another is forother gases such as 13C02 and 15N2), several Pirani
and absolute gauges, a rotary pump for evacuation,
many air-operated and electromagnetic valves, anda programable controller. For connection of all pipes
the Swagelok tube fitting is used. For second traps
a metal seal called Helico Flex is used. The operating status is graphically displayed on the handlingboard.
The gas flow rate to the ion source is adjusted bya pressure controller (PC). Two mechanical booster
pumps are connected to an exhaust of a diffusion
pump to compress gases instead of a rotary pump
(MRP) used in the normal operation of cyclotron
evacuation. Gases collected are passed through
PG3

PG2

8G3

BG4
MB2
MBI

(])

BAW)

c

PGO
VO

or 13CO Z

Gas bottle

GEV19.

Cyclotron
vacuumchamber

GEV20

Ion source
GEV17

Main pumpi'ng
systemCirculation line

Fig. 1. Block diagram of the gas circulation and gas-feed system for the ion source.
RP1 and MRP, rotary pumps; RP2, circulation pump; MB, mechanical booster pump;DP, diffusion pumps of 32 /1 and 14 /1 connected in series; OF, oil filter; F, filter; BAV,
GAV, AV and S3, air-operated valves; V, hand valve; GEV, electromagnetic valve; R1
and R2, reservoirs of 15 I; R3 and R4, reservoirs of 0.1 I; T1, thermoelectrically cooled
charcoal trap; T2 and T3, liquid nitrogen cooled charcoal traps with baking heater wound(these traps are set in a thermos with a lifter moved by a motor); PR, pressure regulator;
PG and BG, Pirani and absolute gauges; PC, pressure controller (100-10- 1 Torr); GFC1
and GFC2, gas flow controllers (GFC1: max 5 cc/min, GFC2: max 10 ccjmin).

210

K. Ikegarni, et ai.

J.£rl Source

Gas

~

50

10
Repetition: 100 Hz
Base Voltage: 44.6 V

iJUl
-l
~

10 mSECc
E........
u

~

8

40

6

30

~

L

B
u

0

Cyclotron Roomc:::Control Room

03:

GFC I: 0"'5 cc/ml n
GFC2: 0" 10 cc/mln

Fig. 2.

~

0
20 LL

4

>.....,

4V>
0

L:J

~

~

=:l
CI

2

10

Block diagram of the gas flow controller.

ofirst and second traps. The first charcoal trap iscooled at temperatures below - 20°C by four
thermoelectric cooling units. Water vapor in theresidual gases is almost trapped by charcoal. Other
residual gases except 3He are adsorbed in the second
trap cooled by liquid nitrogen.
The system is automatically operated by simply
starting the programable controller after we select areservoir to be filled with gas and traps. After evacuating the system and cooling the traps, gas is supplied
from the reservoir into the system by using the circulation pump and circulated to be purified throughtraps in the system. After purification, the gas is sent
through a pressure controller to the ion source andrecovered from the cyclotron chamber back to thesystem. When the circulation is stopped, the gas
used is recovered into the reservoir by the circulation pump after purification. To remove gas adsorbed in the traps, the traps are evacuated with therotary pump (RP1) for several hours while thetraps are heated to around 70°C and 150°C at thefirst and second trap, respectively.
2) Gas-feed System
This system consists of eight gas bottles eachhaving a pressure regulator, several air-operated andelectromagnetic valves, and two gas-feed lines for
mixing gases with a gas flow controller. A gas flow
controller is composed of a piezoelectric valve (PV10) and a mass flow meter. Figure 2 shows a block

2

4

6

8

10

a

Dial Number of Controller
Fig. 3. Gas flow rate and corresponding duty factor of theelectric pulse applied to the valve according to a dial numberof the controller.

diagram of the gas flow controller. The valve PV-10
is operated by an electric pulse with a repetition
rate of 100 Hz and an amplitude of 40-100 V. By
varying the pulse duration from 0 to 50%, one gas
flow controller (G FC 1) can control the flow rates
over the range of 0-5 cc/min and the other controller (GFC 2) from 0-10 cc/min. Figure 3 shows a
gas flow rate for nitrogen gas vs. the duty factor of
the electric pulse applied to the PV-IO. In the caseof mixed gas, 1) the main gas is supplied to the ion
source through one gas-feed line and the supportinggas is supplied through the other line to produce
highly-charged heavy ions and to allow stable operation of the ion source.
The system is operated by simple button push
after the required gas is selected. When the switch"START" is pushed on the graphic panel, thesystem is evacuated and gas is fed in the ion source.
Reference
1)

K. Ikegami, K. Ogiwara, T. Kageyama, and 1. Kohno:
Proc. 6th Symp. Ion Source and Ion-Assisted Tee., p. 155(1982).

211
RIKEN Accel. Progr. Rep. 18 (1984)

V-21.

Low-~ RFQ Structure-II: High Frequency Model Measurement

M. Odera and M. Hemmi

Design of a model of the four-vane type 10w-f3
RFQ structure was described in the previous
report.!) It has a rectangular cross section for its
outer shell and has different heights for the horizontal and vertical vanes to try separation of theunwanted H-ll dipole mode fr'o m the H-21 quadrupole acceleration mode. It is also fitted with current shorting ring between the vertical vanes to reduce
number of resonant modes near the wanted mode. I )Its cross sectional view is·shown in Fig. 1. The vertical height of the fabricated model is 300 mm, thehorizontal width is 150 mm, and the axial length is
600 mm. An aperture for beam, initially 5 mm, wasexpanded to 10 mm for convenience of bead pulling
perturbation measurements.
Table 1 shows resonant frequen.~i~~_ measured
for the two apertures. Large separation intended forthe unwanted modes from the wanted one has beenrealized and the separation remains substantiallyconstant against the change in the aperture. Other
resonant frequencies were not observed below 400
MHz. Two current shorting rings connecting vertical vanes reduced the number of the resonant modes.
Figure 2 shows a field distribution for the H-21
mode along the beam axis. The reproducible andsharp field change reflects roughness of the vane
tip surface. The small asymmetry of the bead position due to the surface roughness with respect to thegap distance between vane tips is amplified by asteep change of electric field strength generated byshift of the central axis of the quadrupolar field.
The distribution shown in the Fig. 2 actually represents a resonant frequency deviation propor-

Vertical vane

Horizontal vane

Table 1.

Resonant frequencies measured below 400 MHz.

Aperture

H-21 mode

H-ll mode

5mm
10mm

189.261207.986204.474
223.026

Cavity axis

Fig. 2. Field intensity distribution along the beam axis for
H-21 acceleration mode, 207.986 MHz.

Cavity axis

Fig. 3. Field 'intensity distribution along the beam axis for
H-ll dipole deflecting mode, 223.026 MHz.

tional to square of field strength at the bead position.
Therefore, the change in the quadrupolar field symmetry caused by the irregularity of the vane tip
surface generates a sharp change as shown in Fig. 2.
On the other hand, the dipole mode H-11 does notshow such high sensitivity to the surface finish as
seen from Fig. 3, and therefore, its field strength
does not change so drastically with position as in
the H-21 mode.
According to these results, the rectangular RFQ
structure seems to have satisfactory characteristics
aimed at first. I) There is no problem in mode discrimination which sometime presents trouble in thecase of the symmetrical four-vane structure because of too close frequency separation. Tolerance
in fabrication is not so tight as in the case of theconventional symmetrical type without a current
shorting ring. Uniformity of the field strength along
the beam axis can be improved by selecting a lengthof vane arms and their separation from the end
plate. That is the subject for further study.
Reference

Fig. 1.

Cross sections of th~ rectangular RFQ structure.

1)

M. Odera: RlKEN Accel. Progr. Rep., 17, 185 ,(1983).

212

RIKEN Accel. Progr. Rep. 18 (1984)

V-22.

Development of the Medium-~ RFQ Structure-III: Study byHigh Frequency Model
M. Odera and M. Hemmi

A previously reported two-cell chain structure!)
was modified and a new model was fabricated togive a larger beam aperture and an ample distance
between the neighboring electrodes to simulate
an actual accelerator. Because the former structure
was developed only to test feasibility of the chain
scheme, no realistic consideration was given in its
geometry and the new model had to be constructed.
However, it is still a constant velocity version, having 10 cells of the same length. Figure 1 is a photograph of the new resonator showing an array ofchain electrodes inside. The tank diameter is 500
mm, the axial length is 600 mm, and the lengthof 277: cell is 60 mm. A gap to cell ratio is taken
as 1/4. Figure 2 shows an electrode assembly whichcorresponds to the length of 477:. A train of suchelectrodes in a horizontal plane is interlaced withanother train of similar assemblies in the verticalplane displaced longitudinally by a length of 277:.
The combination results in the chain-like accelerating
structure in which acceleration and focusing regions
alternate along the beam axis.
Resonant frequency spectra are shown in Fig.
3. No unwanted mode is present below 460 MHz
for (a) and the nearest unwanted mode is separated
from the wanted acceleration mode at 264 MHz by
Frequency

Frequency

Q- vafues

1000

Q- va lues

987.96973.23959.05944.32 943.84
941.40 940.93

900
800

N

700

784.6
768.30 7G7 .43( TM 110 )724.25 ( TM 020)

600

4000

N

6

Ul

Ul

<I>

<I>

3 400
13700

604.80575.80<I>

5- 500

~

:J

CT

~

+-'

+-'

C

ro

400

c
~

<I>

<I>

a:::

m~~ j~U~

715.00 709.40
68.1.39659.]9651.51

c

C
<I>

c
c
~

16000

'0

'0

ro

~~t~~

776.96 776.53
775.69

10000

:r:

:r:

~
~

823.73827.72 824.78

a:::300264.12 (TM - 010) 6000

264.17 (TM - 010) 5500
215.30

200

3200

100
Fig. 1.

Photograph of the type-2 resonator model.

aFocus.
regionAcceleration
gap
chain unit inr--=-...:..-+--"'----+------t-~-t--'__'____t
pi a ne of pa per

I(b) Cavity without slots
for evacuation

Fig. 3. Resonant frequency spectra. (a) With axial slots inthe cavity wall, (b) slots closed.

L(21r) .

41r

Fig. 2.

(a) Cavity with axial slots
for evacuation

Sectional view of a chain electrode array.

Fig. 4. Distribution of the accelerating voltage in gaps at
264.12 MHz for the TM-010 acceleration mode.

M. Odera, et al.

213

Fig. 6.

(a)(b)

Fig. 5. TM-110 modes. (a) At 767.43 MHz, (b) at 768.30
MHz.

49 MHz for (b). An Alvarez linac having 10 cells
usually presents a closely spaced frequency spectrum called a dispersion curve, when plotted as afunction of a phase difference between adjacentcells. In the case of (a), axial slots in the outerconductor of the cylinder simulating evacuation
port were somewhat effective to suppress the resonant mode in which current flows azimuthally. As
seen in (b), however, the closure of the slots had not
influence on the frequency spectrum essentially.
Of course the number of modes which have azimuthal current components increased. But theincrease is seen in the frequency higher than 575
MHz except one at 215.3 MHz, 49 MHz lower than
TM-OI0. The nature of the lowest frequency mode
has not been clarified yet. The reason of the scarcityof the resonant modes near the TM-OI0 mode in
the chain structure is interesting for further study.
The large separation of the nearest modes simplifies
resonator fabrication and tuning.
Field distribution was studied by using a usual
perturbation technique. Figure 4 shows a plot of

TM-020 mode at 724.25 MHz.

frequency deviation which is proportional to squareof the field strength at the position of the perturbing
metallic bead for the TM-OI0 mode. Peaks at the left
and right ends correspond to voltage for half cells
and are lower than those for normal cell. This distribution is suitable for beam acceleration. Othersignificant modes are also described below.
Figure 5 gives the distributions for the two TM110 modes. For these modes, the magnetic field isconcentrated in the acceleration gaps whereas thestrong electric field exists there for the TM-OI0.
Therefore, the direction of frequency deviation by
perturbation in Fig. 5 is contrary to that in Fig. 4.
Shifts of the large and small peaks by 2n- are seen
between the two TM-110 modes. The change corresponds to rotation by 90 of the position of thenodal plane of the TE-II0 mode. A distribution for
TM-020 is also shown in Fig. 6.
The highest quality factor was observed for the
TM-110 modes for which no electric field is present
in the acceleration gaps and in the focusing quadrupoles. The gaps and the poles do not capacitively
load the cavity in that mode and give the high Qvalues. By pulling a metal bead perpendicular tothe beam axis, the electric field by the TM-II0
mode was found to be concentrated somewhere
between the beam axis and the cavity wall.
The obtained distribution confirms the possibilityof use of this structure as a linear accelerator. The
obtained field distribution reproduces the previously
reported distribution measured by a two cell ,magnetic analog model when the latter is squared.
Reference
1)

M. Odera, M. Hemmi, T. Chiba, and E. Ikegami:
RIKEN Accel. Progr. Rep., 17, 183 (1983).

214

RIKEN Accel. Progr. Rep. 18 (1984)

V-23. Development of the Medium-,8 RFQ Structure IV: Effect ofChange of Cell Length, Measurements by Magnetic Analog Models
M. Odera and M. Hemmi

Transit time factor of an RFQ structure with achain-like electrode configuration which we call
type-1 was calculated using the field distribution
Table 1.

Parameters of the magnetic models. *Model number

L (mm)
Cell length
g (mm)
Gap length
Plate thickness t (mm)Pole lengthd (mm)

#1

#2

#3

#4

60
15
10
12

90
22.5
15
18

120
30
20
24

150
37.5
25
30

* giL is 1/4, beam aperture is 10 mm, aperture of quadrupoles is 20 mm, and other transversal dimensions are kept
constant. Letters representing parameters are the same as
those of Fig. 1.

o· transverse

Axial field along central axis

membermeasured by a magnetic model and reported inRef. 1. An effective shunt impedance obtained israther high showing possibility to realize a linac
economical in power consumption. I) Another model
which we call type-2 having more realistic dimensions was fabricated and the field distribution in it
was measured and reported elsewhere. 2) The transit
time factor obtained for the new model was 830/0
at the acceleration gaps and a little smaller than thevalue of 900/0 of the type-1 reported l ) in spite of useof the same gap to cell ratio. The cell length was
48.9 mm and the beam aperture was 6 mm for the
first type, whereas 60 mm and 14 mm, respectively
for the second type. This shows sensitivity of thetransit time factor on the geometry of the electrode.
In order to study the geometry effect further,four magnetic models with different cell length were
fabricated. 3 ) In those models, longitudinal dimen.J::

500

tiD
c
~
VI

::Q

ro

.~

ro 200

300

~ 200

'x
co

co

>

:;:;

Qi

a::

300

Q)

;;::

Q)

100

100

~

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

Qi

0~-4------~~----~------~---­

a::

- 100

- 100

- 2000 20 40 60 80 100 120 140 160 180 200-20°0

Axial position . (mm)Axial position (mm)
(a)

(b)

.J::

400

300

e

tiD

250

V; 200
"0

~ 150

~ 100
co
~

50

:;:;

~
a::

0
- 50

-100020406080100120 140160180200 220 240260280300
Axial position (mm)(c)

Axial position (mm)(d)

Fig. 1. Distribution of axial field measured by Hall probes. (a) For number 1 geometry,(b) For number 2, (c) For number 3, (d) For number 4.

215

M. Odera, et al.

ell
:::J

300

3)()

a

ell

200

200

200

100

100

g
.~

~

0::

100

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

6

2 4 6

-6 -4-2

~

-· -

-100

::::-...

"

-200
-300
(a)

-300
( b)

x·+-lt---·----g-EL(]~

lEo Focusig
region

"I

-300
(c)

(d)

Fig. 2. Focusing field in the quadrupole gaps. Pole to pole distance is 20 mm. (a) At thecenter of quadrupoles. - - , Probe moves in the plane of paper; ---, probe perpendicular to paper. (b) Axial position 4 mm from the center. (c) Axial position 10.2 mm from thecenter or 3.7 mm from the pole edge. (d) Longitudinal cross section of the chain structure
showing the axial position of measurement of the focusing field.

sions were taken proportional to the cell length
whereas transversal parameters were kept constant.
Table 1 gives the parameter values. Letters denoting
parameters correspond to those in Fig. 2 of a preceding paper. 4)
The four curves in Fig. 1 are values measured forthe two-cell magnetic models. In the measurements,
the left-hand side beam aperture was filled with plugs
made of soft iron in order to see effect of beam
aperture on the field distribution. Hall probes wereinserted from the right-hand side. The effect ofbeam aperture is clearly seen in the change of field
amplitude which is the largest at the left end where
the plug fills the aperture and then decreases towardright direction. Figure 2 shows transversal focusing
fields in the quadrupole region. A little difference isseen among field gradients in the directions per-pendicular with each other as expressed by dash anddot, and a solid lines when position of measurement
is displaced axially from the center of the focusing
region. However, larger asymmetry is always present
in the usual RFQ structure and is not harmful fororbit stability. Calculation of the transit time factor
by using the obtained results is in progress.
References
1)

M. Odera, M. Hemmi, T. Chiba, and E. Ikezawa:
RIKEN Aeeel. Progr. Rep., 17, 183 (1983).
2) M. Odera: Proc. 1984 Linear Accel. Conf., Seeheim,
GSI-84-11, p. 36 (1984).
3) As to a photograph of the magnetic model, see Fig. 4 ofthe paper; M. Odera, M. Hemmi, A. Goto, M. Hara,and M. Kase: Proc. 5th Symp. Accel. Sci. Technol.,
Sept. 1984, KEK Tsukuba, p. 56 (1984).
4) M. Odera and M. Hemmi: p. 212 in this report.

216
RIKEN Accel. Progr. Rep. 18 (1984)

V-24.

Application of the Medium-j9 RFQ Structure
M. Odera, M. Hemmi, A. Goto, and M. Hara

According to a previous model study, a new RFQ
structure of the Alvarez type with a chain-likeaccelerating electrode configuration was found likely
to have a moderate effective shunt impedance. I)
Since exact evaluation of the effective shunt impedance for such a complex construction is difficult,rough estimation was made according to a following
procedure. The dimension of drift tubes of a twocell Alvarez cavity which has an outer conductor of
the same diameter as that for the chain model were
calculated by the "Super Fish" code to give thesame resonant frequency. Drift tubes thus determined were fabricated and installed inside thecavity shell in place of the chain electrodes and thequality factor was measured. Assuming that theshunt impedance is proportional to the Q-value, wehave obtained a value larger than 100 MQ/m.
On the other hand, the chain model fabricatedfor the comparison with the Alvarez type had a few
defects; edges of the electrodes were not rounded
and the distance between quadrupoles was so smallthat it is not likely to hold acceleration voltage. The
aperture in the accelerating electrodes for beamtransmission was also too small. Field distribution
and the Q-value may be changed if these defects
are modified. A second high-frequency model was
fabricated taking account of these considerations.
The new model has 10 cells but is still a constant velocity version having the same length forevery cell. Its characteristics measured are described
separately in this report. 2) The effect of change incell length by increase of velocity on the field distribution has been studied by the magnetic analog
models and the result was also given separately.3)
However, comparison with the Alvarez type as madefor the two-cell model of the first type has not been
made yet. Instead, we are planning to fabricate an
acceleration model which has a different cell lengthfor every cell reflecting increase in velocity of ionsby acceleration. Field distribution and the Q-value
may be different from those for the constant velocity
model. We intend to measure the effect of unevencell length on the effective shunt impedance by thethird model.
If the high effective shunt impedance is confirmed for the realistic third model again, thisstructure will find several applications not only
because of power economy but also of its simplicity

of operation. Once the best geometry of the chain
electrodes is established, fine tuning of the focusing
elements, as is often necessary in the ordinary drift
tube linacs, will not be required. Since the strength
ratio of the accelerating to the focusing fields is
automatically maintained constant, the beam trajectory becomes invariant against the change in themass to charge ratio of the ions under acceleration.
On the other hand, exact determination of the field
configuration along the beam trajectory must be
made by using models to allow prediction of theorbit characteristics by numerical integration.
A few examples of use of the structure are mentioned here.
Case 1: Increase in energy of ions of heavy elements accelerated by the RILAC.
At present, ions having a mass to charge ratio(Alq) of 20 are being accelerated up to 0.8 MeVIn
at 20 MHz. This ratio can be decreased by charge
stripping at the exit of the RILAC and the ionsare further accelerated by the chain structure
operated at a frequency of integer multiple of 20
MHz. The linac of 3.6 m long operated at 200
MHz is capable of accelerating ions of Alq smaller
than 7 up to 1.8 MeV/n and the maximum power
consumption will be 140 kW for an axial field
gradient of 1.5 MV1m, on the assumption that theeffective shunt impedance is 100 MQ/m.
Case 2: Increase in intensity of light heavy ions.
Singly or doubly charged ions of which mass islighter than that of N e can be accelerated at a
reduced power level by the RILAC at 20 MHz andsimilarly by the structure of Case 1. For these ionscharge stripping at 0.8 MeV/n by gaseous media
between the RILAC and the booster to make Alq
ratio smaller than 5 is feasible and the high intensity
will cause no problem of lifetime of the strippers.
After the ions are accelerated up to 1.8 Me VIn, a foil
stripper is used to reduce the Alq value to 2 andfurther acceleration by another 8 m section can
increase energy up to 7 MeVIn. A necessary RF
power is 140 kW for a field gradient of 1 MV/m,
neglecting a probable change in the effective shunt
impedance due to change in velocity.
Case 3 : Increase in energy of light ions accelerated
by the RILAC at 40 MHz and charge stripped to
Alq=2.
The RILAC energy operating at 40 MHz can be217

M. Odera, et al.

Table 1.

Examples of the possible applications of the new Alvarez type linac with the chain-like accelerating electrodes.

Case
No.

El n

Eout

MeVjn

MeVjn

Ajq

Cavity length(Ace. Grad.)mat (MVjm)

Freq.
(RILAC)MHz

Freq.
(Chain)
MHz

2
3
4*

0.8
0.8
3.2
0.8

1.8
7.0
7.1
10.6

7
2
2
1

3.63 (1.5)
3.63+7.98 (1.0)
5.07 (1.2)
6.29 (1.2)

20
20
40

200
200
200
200

* Injected from a rectangular low-/3 RFQ linac. 4 )increased from 3.2 MeVjn up to 7 MeVjn by use ofa 5 m long section operated at 200 MHz. Powerconsumption is 130 kW for the field gradient of 1.2
MV jm. For acceleration of protons the power loss
becomes 1j4.
Case 4: Acceleration of intense protons.
Combined with the rectangular four-vane typelow-fi RFQ linanc,4) the structure can be used as
an economical high intensity proton accelerator.
For instance, by receiving protons at 800 keY fromthe low-fi section, the linac of 6.3 m long is sufficient
to boost energy up to lOMeV jn. Power consumption is around 160 kW for the shunt impedance of
100 M-Qjm and the field gradient of 1.2 MVjm.
Such a proton linac is useful as a prototype highintensity accelerator. It is desired for study of heavyradiation damage of fusion materials or as an injectorof a high energy and high intensity linac for a pion
generation or for a spallation neutron source, as
well as for the RIKEN separated sector cyclotron
under construction.
Power consumptions in the above examples are
given only for rough estimation of the RF equipments and should be examined by further study.
The axial field gradients were chosen so that thepower consumption per resonator remains less than

200 kW. The gradients and other parameters are
summarized in Table 1. For accelerating frequencyof the chain structure, 200 MHz has been usedthroughout for the sake of simplicity of presentation.
Higher or lower frequency is also possible and will
be chosen by considering availability 6f the highpower-high frequency tubes in the market, ease ofstructure construction, and so forth. The end
energy was arbitrarily chosen and should be modified
according to acceleration conditions in the post
stripper part. For instance, if it is used as an injector
to the separated sector cyclotron, velocity of the ionsmust satisfy conditions of the subharmonic acceleration in the circular orbit of the cyclotron.
The maximum surface field sustainable for the
structure must also be studied carefully, though useof the extremely high field is frequently reported in
the recent RFQ linac papers.
References
1)

2)
3)
4)

M. Odera, M. Hemmi, T. Chiba, and E. Ikezawa:
RIKEN Accel. Progr. Rep., 17, 183 (1983); M. Odera:
Proc. 1984 Linear Accel. Conf., Seeheim, GSI-84-11, p.
36 (1984).
M. Odera and M. Hemmi: p. 212 in this report.
M. Odera and M. Hemmi: p. 214 in this report.
M. Odera and M. Hemmi: p. 211 in this report.

218

RIKEN Accel. Progr. Rep. 18 (1984)

VI.

RADIATION MONITORING

1.

Leakage-Radiation Measurement in the Underground Passageof the Cyclotron Building
S. Fujita, 1. Sakamoto, H. Takebe, and I. Kohno

1) Measurement with a film badge
Leakage doses measured from April, 1983, to
March, 1984, with r-ray and neutron film badges
which were placed at two positions of the underground passage (points A and B in Fig. 1) are
shown in Table 1. In this period, the beam times
allotted to deuteron acceleration were 63 hr in July,
72 hr in December, and 72 hr in March. Fastneutrons were generated at the end of the beamcourse No.2 by bombarding a thick beryllium target
with 20 MeV deuterons in December. The average
beam current was 15 f.1A. The average energy and theflux of the fast neutrons were estimated using data
in Ref. 1 and 2 to be 5 MeV and 4 x 1012 n·cm- 2 •sec- I, respectively, in the direction of a O-degree
angle at the center of the target.
2) Measurement with a radiation detector
Leakage-radiation in the underground passage

was measured when the cyclotron was operating on
12 MeV proton (target silicon), 24 MeV deuteron(target beryllium), 18 MeV helium-3 (target silicon),and 28 MeV alpha (target argon). All targets were
set on the end of the beam course No.2. As shownin Figure 1 the measuring points of radiations aremarked at intervals of 2 m from point C in the underground passage and the measuring points on thestair have a distance of 14 m 0), 16.5 m (K), and19 m (L) from point C. The measurements werecarried out from October to December, 1983.
The neutron radiation was measured with a remmeter* using a pulse counter.** The value of pulse
counts obtained during 10 min at 0.5 m above thefloor was converted into the dose equivalent rate byusing the conversion factor, 3.6 cps per mrem/hr
given in the instruction manual. The mlmmum
detectable level of neutron dose rate in this mea-

Experimental area (S)Experimental area I(L)

L...L.L..L..L.Jo 1 23.4 Sm

-

:
I

I

Undergroundpassage
M ~ ___ ,C l xxA 1 0

I
II

Underground/ :passage
I

oX -

[
o

L
Hand foot cloth
monitorK

Control room

Ground plan

Fig. 1.

L K

~
oI
P

x

Basement

Measuring positions of neutron and r -ray dose rates in the cyclotron building.

* Neutron Dose Rate Meter 2202D, manufactured by AB
Atomenergi, Sweden.

** UP/DOWN Counter MH-712A, manufactured by Honda
KIT, Japan.

x

UP x I
x J

UP

219

S. Fujita, et al.

Table 1.

Leakage-radiation dose (in mrem) in the underground passage of the cyclotronbuilding from April, 1983 to March, 1984.
Position*

Radiation
B

A...

Deuteronr-Rays (mrem)
Thermal neutrons (mrem)
Fast neutrons (mrem)
Total (mrem),

July**

December

March

2,530
780
10
3,320

9,790
2,610
17,55029,95020
0
020

Other ions

Total

2,200
590
170
2,960

14,5403,980
17,73036,250

70
30
20
120

* Positions indicated in Fig. 1.

** The beam times allotted to deuteron acceleration in July were 63 hr, but the values were obtained by measuringfor 27 hr.

Table 2.

Neutron dose rates (mrem/hr) at points P and Q.
H eight above the floor

PositionP
Q
456
Target beam Current (fJ.A)

Fig. 2. Neutron dose rates at point C vs. the target beam
current when the cyclotron was operating on 28 MeV alpha.

10- 0

x

_,

6\ 0"'-%0"",
I/;j\ '..

x

proton0•eutronalphad,\~~~ helium- 3

~.
:!~
"'D.~
o"--~
/ : // '

6

'.

0

\

\~

\r

.

I,

1'·

protondeutron-alpha0

helium- 3 \'1
1O-5L--~4---2-::----~O:---2=--~4:----±-6--.-J8~1:-'::O:----!'1'-::-2~14-:--:1:-::6:-:.5::--71"="9---1
NMCDEFGHI
Distance from point C (m)

J

K

L

Fig. 3. Attenuation curves of neutron dose rates and r-ray
dose rates. The solid line shows neutron dose rates and thepoints indicated by x, 0, . , and D. show r-ray dose rates.

surement was about 1 X 10-4 mrem/hr. The neutronradiation was also measured with a rate meterequipped with the rem meter. The range of measurement with the rate meter was 0.1 to 10,000 mrem/hr
The ratio of neutron dose rates with the pulse
counter of the rem meter to those by the rate meter
was about 1.4 at point C. The r-ray dose rate wasmeasured with a GM survey meter,* and the* Geiger-Muller Counter Tube Type Radiation Survey
Meter SUM-BG6, manufactured by IPCR.
** Multi-pen Recorder KA-62-32L, manufactured
Rikadenki, Japan.

by

0.5 m

1.4 m

0.28
0.19

0.35
0.10

value of the target beam current was recorded byusing an electronic recorder. **Figure 2 shows the neutron dose rates at point C
as a function of the target beam current when thecyclotron was operating on 28 MeV alpha. Since
the dose rate is proportional linearly to the beam
current, the dose rates measured at given target beam
currents were normalized to the dose rates per unit
target beam current.
The attenuation curves of neutron dose rate andr-ray dose rate are shown in Fig. 3. These attenuation curves indicate that:(1) Attenuation of the neutron dose rate wasobserved clearly in the low dose rate range,
because the neutron was measured by the rem
meter with pulse counter.
(2) The neutron dose rates rapidly decreased at
distances larger than 14 m from point C, because the passage is curved to the right angle
and the area at the end of the undergroundpassage is open.
(3) In Fig. 3 the r-ray dose rates are comparedwith neutron dose rates. The ratios of r-ray
dose rate to neutron dose rate were about
0.5-1.0 on acceleration of deuteron, helium-3,
and alpha. When the proton was accelerated,
the ratio became larger as the measuring points
approach the cyclotron vault. The ratios
measured at points A, C, D, and E were> 17,
14, 1.5, and 3, respectively.
There is a hole (point 0) through which many
cables run between the cyclotron vault and theunderground passage. In order to know the streaming effect through this hole we measured neutron
dose rates at 1.4 m and 0.5 m above the floor at

220

S. Fujita, et ai.

points P and Q. The results are listed in Table 2.
The neutron dose rate at 1.4 m of point P was
higher than that at 0.5 m, and that at 0.5 m of point
Q was higher than the dose rate at 1.4 m, because
the leakage neutrons from the hole were added tothose from the cyclotron vault.

References
1)

2)

M. A. Lone, C. B. Bigham, J. S. Fraser, H. R. Schneider,
T. K. Alexander, A. J. Ferguson, and A. B. Mcdonald:
Nucl. Instrum. Methods, 143, 331 (1977).
H. Kamitsubo, I. Kohno, S. Motonaga, M. Yanokura,
T. Shikata, M. Yatsuhashi, T. Suematsu, and H. Kobayashi: RJKEN Accei. Progr. Rep., 16, 118 (1982).

221
RIKEN Accel. Progr. Rep. 18 (1984)

VI-2.

Routine Monitoring of RIKEN Accelerators

I. Sakamoto, S. Fujita, M. Yanokura, T. Kobayashi, and K. Igarashi

Results of routine radiation monitoring carriedout on the cyclotron, RILAC, and TANDETRON
from April, 1983, to March, 1984, are described.
Some aspects of the leakage radiation from thecyclotron are described in the succeeding report.
1) Residual Radiation of the Cyclotron
In December, 1983, the cyclotron had been operated for about 70 hr with 20 MeV deuteron and withtarget beam current of 10-20 pA. The dose rates due
to residual activities of the machine were measured
17 days after machine shutdown. The result is shownin Table 1.
The external exposure doses of two workers during replacement of septum were 20 and 30 mrem.
2) Surface and Air Contamination in the Cyclotron Building
The surface contamination has been kept below
10- 5 pCijcm 2 on the floor of the cyclotron vault andbelow 10-6 pCijcm 2 on the floors of the experimental
areas, underground passage, hot laboratory, andchemical laboratories. The radioactive nuclides
found by r-ray spectrometry were 65Z n , 1850s, 183Re,
Table 1.

Dose rates of residual activities.

Location

Dose rate (mRjhr)

ca. 70 cm apart from septum(before replacement of septum)
ca. 20 cm apart from septum holder(after replacement of septum)
at top of dee
Baffle box before BE magnet

Table 2.

100
100
100
30

and 184Re. The contamination was wiped off twicea year, and immediately after this decontamination,
the contamination on the floor of the above places
was reduced to a value below 10- 7 pCijcm 2.
When the radioactive substances were handled
in the hot laboratory and chemical laboratories, theair in the draft chamber was contaminated byradioactivity. The air in the draft chamber wasdischarged through an exhaust, and the radioactivity
in the exit was below 10-12 pCi/cm3.
3) Drainage
The radioactivities in the drain water from thecyclotron and linac buildings were found to be of
the order of 10-8-10- 4 pCi/cm3. The total activities
in aqueous effluents in this period was about 100
mCi, and the main radioactive nuclide was tritium,
and the other nuclides could not be detected by the
r-ray spectrometry.
4) Radiation Monitoring of RILAC andTANDETRON
Leakage radiation during operation of RILAC
was measured at the circumference of the linac
building every month. No leakage r-rays and neutrons from the linac building were detected.
The surface and air contamination due to residual
activities could not be found in the radiation control
area in the linac building.
X-ray monitoring was carried outon
TANDETRON when boron ions were accelerated.
When a vanadium target was bombarded by 2 MeV
B2+ ions at 0.82 nA, the maximum dose rates

Annual exposure doses received by RIKEN accelerator workers from April, 1983 to March, 1984.
Number of persons
Workers

Cyclotron operation and maintenance group
Linac operation and maintenance group
Nuclear physicists
Accelerator physicists
Physicists in other fields
Nuclear chemists
Radiation chemists
Biological chemists
TANDETRON workers
Health physicists
Total

Dose
undetectable

10-100(mrem)

2
8
4
11
22
3
4
10
12
8
84

6
2
4
3
3
7

2S

>100
(mrem)

2

Average annual dose per person: 8.6 mrem; Maximum individual annual dose: 140 mrem.

Total

8
10
8
14
26
11
4
10
12
8
111

Collective
dose(man-mrem)

230
20
100
40
190
380

960

222

I. Sakamoto, et al.

measured around TANDETRON and at the outside of the TANDETRON room were 3.9 and 0.12
mRjhr, respectively. No leakage X-rays could be
detected around the target chamber.
5) Personnel Monitoring
The external exposure doses to personnel were
measured by using r-ray and neutron film badges.
The doses received during the present period by all
RIKEN accelerator workers are shown in Table 2.

The collective r-ray dose to all workers was 960
man-mrem, while the collective dose owing tothermal and fast neutron exposures was too small tobe detected. The collective dose to the workers wasequal to that in the preceding period.
In this period the average annual dose per person
was 8.6 mrem, and the maximum individual annual
dose was 140 mrem.

223

VII.

LIST OF PUBLICATIONS

1. Accelerator development and accelerator physics
1) M. Odera: "Operation of the Riken Variable
Frequency Heavy-Ion Linac, RILAC," Proc.
China-Japan Joint Symp. on Accelerators for
Nuclear Science and Their Applications, Ed.
Yang Chenzhong and Wei Bowen, Lanzhou,
p. 103 (1983).
2) M. Odera: "Recent Progress of RIKEN
Linac, RILAC," Proc. Int. Symp. on Heavy
Ion Inertial Fusion, Ed. T. Katayama, INS,Tokyo, p. 425 (1984).
3) M. Odera: "Report on Frequency Tunable
Linac," Proc. 1984 Linear Accelerator Conf.,
Seeheim 1984, Ed. N. Angert, GSI-84-11,
p. 36 (1984).
4) M. Kase, T. Kambara, T. Tonuma, and M.
Odera: "Beam Quality of the Variable-Frequency Linac, RILAC," Proc. 1984 Linear
Accelerator Conf., Seeheim 1984, Ed. N.
Angert, GSI-84-11, p. 145 (1984).
5) M. Odera and M. Hemmi: "Accelerating
Structure with Chain-Like Electrode Structure," Proc. 1984 Linear Accelerator Conf.,
Seeheim 1984, Ed. N. Angert, GSI-84-11, p.
346 (1984).
6) I. Kohno: "Current Status on Confinement
Ion Sources for Multiply Charged Heavy
Ions," ]. Accel. Sci. and Tech. (in Japanese),
2, 53 (1984).
7) Y. Yano: "RIKEN Accelerator Facility,"
Genshikaku Kenkyu (in Japanese), 28, 341(1984).
8) M. Odera, Y. Chiba, T. Tonuma, M. Hemmi,
Y. Miyazawa, T. Inoue, T. Kambara, M.
Kase, T. Kubo, and F. Yoshida: "Variable
Frequency Heavy-Ion Linac, RILAC. I.
Design, Construction and Operation of Its
Accelerating Structure," Nucl. Instrum.
Methods, 227, 187 (1984).
2. Nuclear physics and nuclear instrumentation
1) T. Fukuda, T. Nomura, T. Shimoda, K.
Katori, S. Shimoura, K. Sueki, and H.
Ogata: "Linear Momentum Transfer in theReaction 232Th(14N, Light Particles) at 208
MeV," Nucl. Phys. A, 429, 193 (1984).
2) J. Kasagi, K. Itoh, T. Kishimoto, M. Sasaki,
and H. Ohnuma: "Gamma Decay of PositiveParity Levels in 45Ti from the 42Ca( a, nr)
45Ti Reaction," Nucl. Phys. A, 414, 206(1984).
3) K. Hatanaka, N. Matsuoka, T. Saito, K.

Hosono, M. Kondo, S. Kato, T. Higo, S.
Matsuki, Y. Kadota, and K. Ogino: "Systematic Study of the (d, p) Reaction with 56
MeV Polarized Deuterons," Nucl. Phys. A,
419, 530 (1984).
4) K. Hatanaka, N. Matsuoka, H. Sakai, T.
Saito, K. Hosono, Y. Koike, M. Kondo, K.
Imai, H. Shimizu, T. Ichihara, K. Nisimura,and A. Okihana: "Measurements of Analyzing Powers Ay , Axx , Ayy and Axz in dp
Elastic Scattering at Ed=56 MeV," Nucl.
Phys. A, 426, 77 (1984).
5) S. Yamaji and M. Tohyama: "Effects of Two
Particle-Two Hole Excitations of the Mass
Distribution in the 160+40Ca Reaction at
E Lab = 157.3 MeV," Phys. Lett. B, 147, 399(1984).
6) Y. Ishibe, S. Ishii, K. Okazaki, H. Oyama,
Y. Sakamoto, K. Yano, N. Noda, K. Toi, S.
Tanahashi, and K. Okubo: "An Attempt to
Improve the Electron Cyclotron Resonance
Discharge Cleaning of a Tokamak Devices,"]. Nucl. Mater., 128 & 129, 889 (1984).
7) T. Kawabe, H. Hirata, M. Ichimura, H.
Kanda, N. Yamaguchi, K. Yatsu, and Y.
Sakamoto: "Wall Conditioning of Gamma
10 Tandem Mirror Device," J. Nucl. Mater.,
128 & 129, 893 (1984).
8) M. Sugawara, Y. Gono, and Y. Itoh: "InBeam r-Ray Study of 217Ra," ]. Phys. Soc.
Jpn., 53, 2956 (1984).
9) K. Hatanaka, M. Fujiwara, K. Hosono, N.
Matsuoka, T. Saito, and H. Sakai: "24Mg(p, d) 23Mg Reaction at 65 and 80 MeV,"
Phys. Rev. C, 29, 13 (1984).
10) H. Kudo, K. J. Moody, and G. T. Seaborg:"Mass Distributions in the Reaction of 240
MeV 12C with 197Au," Phys. Rev. C, 30,
1561 (1984).
11) Y. Nagame, H. Nakahara, K. Sueki, H.
Kudo, M. Yanokura, and I. Kohno: "Studies
on Strongly Damped Components in Relatively Light Heavy Ion Reaction Systems,"
Z. Phys. A-Atoms Nuclei, 317, 31 (1984).
12) A. Hashiba, K. Masuda, T. Doke, T. Takahashi, and Y. Fujita: "Fano Factor in
Gaseous Argon Measured by the Proportional
Scintillation Method," Nucl. Instrum. Methods, 227, 305 (1984).
13) K. Asahi, M. Ishihara, H. Kamitsubo, N.
Takahashi, Y. Nojiri, T. Minamisono, A.
Mizobuchi, and K. Sugimoto: "Measurement

224

of Ejectile Spin Polarization in Heavy Ion
Reactions via f3 Decay Asymmetry," Nucl.
Instrum. Methods, 220, 389 (1984).
14) Y. Ishibe, S. Ishii, K. Okazaki, H. Oyama,
Y. Sakamoto, K. Yano, T. Nozaki, M . Aratani, S. Hayashi, 1. Kohno, N. Noda, K. Toi,
S. Tanahashi, K. Akaishi, and K. Okubo:"ECR Discharge Cleaning in the JIPPT -II
U Torus Device," Shinku (in Japanese),27, 376 (1984).
15) Y. Sakamoto, S. Ishii, K. Okazaki, K. Yano,
N. N oda, and R. E. Clausing: "ECR Discharge Cleaning for the TEXTOR Device
II," Shinku (in Japanese), 27, 380 (1984).
16) H. Ohsumi, H. Ejiri, T. Shibata, Y. Nagai,
K. Okada, T. Motobayashi, N . Noumachi,
A. Shimizu, and K. Maeda: "Neutron Spectroscopy for Giant Resonance," Proc. Int.
Symp. on Nuclear Spectroscopy and Nuclear
Interactions; World Scientific Publishing Co.,
Singapore, p. 317 (1984).
17) T. Nomura and T. Sugitate: "Energetic
Light-Particle Emission and Its Polarizationin Heavy-Ion Reactions," Butsuri (in Japanese), 39, 261 (1984).
18) T. Nomura: "Evidence for Lower AngularMomentum Cutoff in Heavy-Ion Fusion
Reactions," JAERI-M 84-085, p. 104 (1984).
3. Atomic and solid-state physics
1) M. Uda, H. Endo, K. Maeda, Y. Sasa, K.
Fujima, and K. Fuwa: "Application of Ion
Induced X-Ray Emission Spectroscopy to
Chemistry," Proc. 2nd Symp. on Ion BeamTechnology, Hosei Univ., p. 129 (1983).
2) K. Maeda, Y. Sasa, Y. Yokode, M. Maeda,
M. Kobayashi, K. Fujima, and M. U da:"Several Applications of PIXE Analysis,"
Proc. 2nd Symp. on Ion Beam Technology,
Hosei Univ., p. 157 (1983).
3) K. Fujima and T. Watanabe: "Electronic
Structure of Cold Neon Plasma," Proc. of1984 Int. Symp. on Heavy Ion Accelerators
and Their Applications to Inertial Fusion(Inst. Nucl. Study, Univ. of Tokyo), p. 571(1983).
4) I. Shimamura and A. C. Roy: "Transitions ·of Molecules between High-AngularMomentum States," Atomic Collision Res. inJapan-Prog. Rep., No. 10, p. 1 (1984).
5) A. Ohsaki, T. Watanabe, K. Nakanishi, andK. Iguchi: "Classical Trajectory Monte
Carlo Calculation for p++(,lrp) --+ (p+p - )+p and e++ (e- p) --+ (e+e-)+p," Atomic Collision Res. in Japan-Prog. Rep., No. 10, p. 3
(1984).

6) Q. Ma, X. Chang, Z. Liu, Y. Liu, and T.
Watanabe: "Distorted Wave Born Cross
Section for p++(p- p) --+ (p +p- )+p," Atomic
Collision Res. in Japan-Prog. Rep., No. 10,
p. 6 (1984).
7) S. Karashima, T. Watanabe, X. Chang, Z.
Liu, Q. Ma, and Y. Liu: "Electron Stripping
Cross Section of Multiply Charged Ions by
Collision with Neutral Atoms," Atomic Collision Res. in Japan-Prog. Rep., No. 10, p. 52(1984).
8) K. Ando, T. Tonuma, S. Kohmoto, H.
Kumagai, Y. Awaya, S. Tsurubuchi, and K.
Sato: "Spectra of Highly Ionized AluminumAtoms in Beam-Foil Experiment," Atomic
Collision Res. in Japan-Prog. Rep., No. 10,
p.73 (1984).
9) T. Kambara, Y. Awaya, M. Kase, H. Kumagai, H. Shibata, and S. M. Shafroth: "Kf3
X-rays from Ar-Ions Passing through Foils,"
Atomic Collision Res. in Japan-Prog. Rep.,
No. 10, p. 75 (1984).
10) S. M. Shafroth, Y. Awaya, T. Kambara, M.
Kase, H. Kumagai, M. Nishida, and H.
Shibata: "Angular Distribution of REC for
Ar 4 + on C at 1 MeV/u," Atomic Collision
Res. in Japan-Prog. Rep., No. 10, p. 78(1984).
11) J. Mizuno, T. Ishihara, and T. Watanabe:"Classical and Quantal Auger Profiles Due toInner-Shell Photoionization near Threshold,"]. Phys. B: At. Mol. Phys., 17, L85 (1984).
12) T. Tonuma, M. Kase, T. Kambara, H.
Kumagai, T. Matsuo, J. Urakawa, H. Shibata,J. Takahashi, S. Ozkok, S. H. Be, 1. Kohno,
and H. Tawara: "Projectile Charge-State
Dependence of Recoil-Ion Charge-State Distribution Produced in Heavy-Ion Impact,"]. Phys. B: At. Mol. Phys., 17, L317 (1984).
13) H. Shibata, K. Kuroki, F. Nishimura, andN. Oda: "Partial Generalized Oscillator
Strengths for Ionization of the Nitrogen
Molecule by 1 keV Electron Impact," ].
Phys. B: At. Mol. Phys., 17, L739 (1984).
14) T. Kambara: "Collisional Quenching of n p
States of 110 MeV H-Like Ne Ions in Gaseous Targets," ]. Phys. B: At. Mol. Phys., 17,
1599 (1984).
15) N. Shimakura and T. Watanabe: "Differential Cross Sections for Li++ Li Collisions Using Molecular Bases: Quantum Effect," ].
Phys. B: At. Mol. Phys., 17, 2638 (1984).
16) S. Hara and H. Sato: "Theoretical Study ofAutoionizing States of Molecules: H2 andHe22+," J. Phys. B: At. Mol. Phys., 17, 4301
(1984).

22517) H. Suzuki, Y. Kajikawa, N. Toshima, H.
Ryufuku, and T. Watanabe: "ElectronCapture Cross Sections from He in Collision
with Bare Nuclear Ions," Phys. Rev. A, 29,525 (1984).
18) H. Suzuki, N. Toshima, T. Watanabe, and
H. Ryufuku: "Exponential Distorted-Wave
Approximation for Charge Transfer in Collisions of Multicharged Ions with Atomic
Hydrogen," Phys. Rev. A, 29, 529 (1984).
19) M. Uda, K. Maeda, A. Koyama, and Y. ·Sasa: "Chemical Effects on F KVV Auger
Spectra Induced by Photon Impact," Phys.
Rev. A, 29, 1258 (1984).
20) E. Yagi, G. Flik, K. Fiirderer, N. Haas, D.
Herlach, J. Major, A. Seeger, W. Jacobs, M.
Krause, M. Krauth, H. -J. Mundinger, and
H. Orth: "Quantum Diffusion of Positive
Muons in Iron," Phys. Rev. B, 30, 441(1984).
21) Y. Yatsurugi, O. Kuboi, M. Hashimoto, H.
Nagai, M. Aratani, M. Yanokura, I. Kohno,
and T. Nozaki: "Studies of a-Si: H Growth
Mechanism by Rutherford Recoil Measurement of Hand D in Films Prepared from
SiH4-D2 and SiD4-H2, Appl. Phys. Lett.,
44, 246 (1984).
22) O. Kuboi, M. Hashimoto, Y. Yatsurugi, H.
Nagai, M. Aratani, M. Yanokura, S. Hayashi,
I. Kohno, and T. Nozaki: "Origin of
Hydrogen in Amorphous Silicon Produced
by Glow Discharge in Si2H6+ D2 andSi2D6+ H2," Appl. Phys. Lett., 45, 543(1984).
23) T. Tonuma, S. H. Be, H. Kumagai, H.
Shibata, M. Kase, T. Kambara, I. Kohno,
and H. Tawara: "Multiple Ionization ofAtoms by Highly Ionized Heavy Ion Impact," Abstracts of International Conference
on the Physics of Highly Ionized Atoms,
Oxford Univ., p. 59 (1984).
24) K. Asai, F. Ambe, S. Ambe, and H. Sekizawa: "TDPAC of r-Rays Emitted froml11Cd ( ~ 111 In) in a-Fe203," J. Phys. Soc.
Jpn., 53,4109 (1984).
25) K. Nishiyama, E. Yagi, K. Ishida, T. Matsuzaki, K. Nagamine, and T. Yamazaki: "NewApproach in p+SR Study on Critical Phenomena in Ni," Hyperfine Interact., 17-19, 473(1984).
26) K. Fukai, K. Shiraishi, E. Yagi, S. Hamada,and T. Sawai: "Measurement of Mean Projected Range for Argon- and Nitrogen-ions
Irradiated in Stainless Steels," J. At. Energy
Soc. Jpn. (in Japanese), 26, 974 (1984).
27) E. Yagi: "Diffusion of Positive Muons in

Metals," JAERI-M83 (in Japanese), p. 19(1984).
28) Y. Sakamoto, O. Nomura, and H. Oyama:"Plasma Chemical Reactions on Solid Surface," J. Chem. Soc. Jpn. (in Japanese), No.
10, p. 1617 (1984).
29) T. Watanabe: "Electron Capture and Loss
Cross Sections by Atomic Collisions," Proc.
of 1984 INS Int. Symp. on Heavy Ion Accelerators and Their Applications to Inertial
Fusion (Inst. Nucl. Study, Univ. of Tokyo),p. 495 (1984).
30) S. Karashima and T. Watanabe: "Charge
Equilibrium of Fast Ions Traversing throughGaseous Media," Proc. of 1984 INS Int.
Symp. on Heavy Ion Accelerators and Their
Applications to Inertial Fusion (Inst. N ucl.
Study, Univ. of Tokyo), p. 561 (1984).
31) S. Karashima and T. Watanabe: "Charge
Equilibrium of Energetic Heavy Ions inGaseous Media (Ideal Atomic HydrogenGas)," Jpn. J. Appl. Phys., 22, 895 (1984).
32) I. Shimamura: "Rotational Excitation of
Molecules by Slow Electrons," ElectronMolecule Collisions, Eds. 1. Shimamura andK. Takayanagi, Plenum Press, New York,
Chap. 2, p. 89 (1984).
33) T. Watanabe, T. Arikawa, 1. Shimamura, andA. Yagishita: "Report on the 13th International Conference on the Physics of Electronic and Atomic Collisions and RelatedSatellite Meetings," Bull. Phys. Soc. Jpn., 39,
203 (1984).
34) M. Sekiya, T. Noro, F. Sasaki, and K. Ohno:"The Calculation of L 23 -MIMI Auger Energy
and Relative Auger Rates for Ar 6 + and
Ar7+," Contribution from the ResearchGroup on Atoms and Molecules, 14, 4 (1984).
35) 1. Shimamura: "Line-Shape Analysis of
Energy-Loss Spectra and Photoelectron
Spectra," Wavefunctions and Mechanisms
from Electron Scattering Processes, Springer,
Berlin, p. 210 (1984).
36) S. Karashima and T. Watanabe: "Equilibrium Charge and LET of Incident Heavy
Ions (Ne and Ar) in Hydrogen Gas," Radiat.
Res., 99, 476 (1984).
37) N. Sakai, O. Terashima, and H. Sekizawa:"Magnetic Compton Profile Measurement
Using Circularly Polarized Gamma-Raysfrom Oriented 191mlr Nuclei," Nucl. Instrum.
Methods, 221, 419 (1984).
38) Y. Sakamoto, H. Oyama, and S. Kakinuma:"Simulation Experiment on Chemical Sputtering of Carbides for the ECR and Glow
Discharge Cleaning," J. Nucl. Mater., 128

226& 129, 867 (1984).
39) S. H. Be and K. Yano: "Production of Negative Ions by Bombarding a Cesiated Metal
Surface with Cluster Ions and Post-Acceleration," Rev. Sci. Instrum., 55, 1928 (1984).
40) Y. Sakamoto and H. Oyama: "Interaction of
TiC with Hydrogen Plasma," Shinku (inJapanese), 27, 383 (1984).

4. Radiochemistry, radiation chemistry and radiation biology
1) T. Ohno, T. Nishimura, K. Nakano, and 1.
Kaneko: "Differential Recovery from Potentially Lethal Damage in Normal Human
Lung Fibroblasts after Irradiation with 60Co
r-Rays and Accelerated N-Ion Beam,"Int.]. Radiat. Bioi., 45, 21 (1984).
2) T. Takahashi, F. Yatagai, T. Katayama, M.
Inada, and S. Konno: "Track Structure
Theories and Their Application for Inactivation Cross Sections of Bacterial Cells," J.
Radiat. Res., 25, 21 (1984).
3) M. Nakamura, Y. Mochizuki, K. Usami, Y.
Itoh, and T. Nozaki: "Infrared Absorption
Spectra and Compositions of Evaporated
Silicon Oxides (SiOx )," Sol£d State Comm.,
SO, 1079 (1984).
4) M. Yuasa, Y. Ogata, H. Nishide, E. Tsuchida,
M. Iwamoto, and T. Nozaki: "Determinationof Chemically Bound Oxygen by 150-0
Tracer Method. Application to Hemoglobinand Synthetic Heme-Bound Oxygen," Chem.
Lett., 1984, 1889.
5) S. Ambe: "Separation of Trace Elements,
In(III), Sn(IV), Sb(V) and Te(IV) by Adsorption on Activated Carbon and Graphite,"]. Radioanal. Nucl. Chem. Articles, 81, 77(1984).

(Papers Presented at Meetings)
1. Accelerator development and accelerator physics
1) Y. Yano: "RIKEN Accelerator Facility,"
INS-Kikuchi Winter School on Accelerators
for Nuclear Physics, Fujiyoshida, Jan. (1984).
2) T. Kambara: "Variable Frequency Heavy Ion
Linear Accelerator," INS-Kikuchi WinterSchool on Accelerators for Nuclear Physics,
Fujiyoshida, Jan. (1984).
3) K. Ikegami, S. Nakajima, Y. Oikawa, S.
Motonaga, and S. H. Be: "Vacuum Systemof the RIKEN SSC," Proc. 5th Meeting
Ultra High Vacuum Techniques for Accelerator and Storage Rings, Tsukuba, Mar., p.
135 (1984).

4) K. Ikegami, K. Nakajima, Y. Oikawa, S.
Motonaga, and S. H. Be: "Status of the
Design of the SSC Vacuum System at
RIKEN ," Proc. 5th Meeting Ultra High
Vacuum Techniques for Accelerators andStorage Rings," Tsukuba, Mar., p. 139(1984).
5) N. Nakanishi, A. Goto, and Y. Yano: "Orbit
Analysis for Off-Centered Beams in the RIKEN SSC," 39th Ann. Meeting Phys. Soc.
Jpn., Fukuoka, Apr. (1984).
6) M. Kase, A. Goto, T. Kambara, and M.
Odera: "Acceleration Characteristics of Variable Frequency Heavy-Ion Linac," 39th Ann.
Meeting Phys. Soc. Jpn., Fukuoka, Apr.
(1984).
7) M. Kase and M. Odera: "Variable Frequency
Linac, RILAC, as an Injector of a Separated
Sector Cyclotron," 10th Int. Conf. Cyclotrons
and Their Applications, East Lansing,
U.S.A., Apr. (1984).
8) A. Goto, N. Nakanishi, and Y. Yano: "Computer Simulations of Accelerated Particles
in the RIKEN SSC," 10th Int. Conf. Cyclotrons and Their Applications, East Lansing,
U.S.A., May (1984).
9) T. Fujisawa, K. Ogiwara, S. Kohara, Y.
Oikawa, I. Yokoyama, M. Hara, I. Takeshita, and Y. Chiba: "Design of the RF
System of the RIKEN SSC," 10th Int. Conf.
Cyclotrons and Their Applications, East
Lansing, U.S.A., May (1984).
10) M. Kase, T. Kambara, T. Tonuma, and M.
Odera: "Beam Quality of Variable Frequency
Linac, RILAC," 1984 Linear Accelerator
Conf., Seeheim, W. Germany, May (1984).
11) K. Ikegami, T. Noda, N. Kamiyama, and I.
Kohno: "Automatic Operation of Gas Circulation and Gas-Feed System for the Ion
Source of the 160 cm Cyclotron," Proc. 8th
Symp. on Ion Sources and Ion-Assisted
Technology, Tokyo, June, p. 115 (1984).
12) Y. Yano: "RIKEN Accelerator Facility,"
Proc. 8th Symp. on Ion Sources and IonAssisted Technology, Tokyo, June, p. 157(1984).
13) M. Yanokura: "Design Study of the RIKENECR II," Proc. 8th Symp. Ion Sources andIon-Assisted Technology, Tokyo, June (1984).
14) S. Motonaga and SSC Group: "Status of
the RIKEN SSC," Proc. 5th Symp. on Accelerator Science and Technology, Tsukuba,
Sept., p. 21 (1984).
15) K. Ikegami, T. Noda, N. Kamiyama, and I.
Kohno: "Automatic Operation of Gas Circulation and Gas-Feed System for the Ion

227

Source of the 160 cm Cyclotron," Proc. 5th
Symp. on Accelerator Science and Technology, Tsukuba, Sept., p. 36 (1984).
16) M. Odera, M. Hemmi, A. Goto, and M.
Hara: "New Alvarez-Type Linac Structurewith Chain-Like Electrodes," Proc. 5th
Symp. Accelerator Science and Technology,
Tsukuba, Sept., p. 56 (1984).
17) Y. Yano and A. Goto: "A Method to Measure Two-Dimensional Motion of Orbit Center with Three Radial Differential Probes,"
Proc.. 5th Symp. Accelerator Science andTechnology, Tsukuba, Sept., p. 133 (1984).
18) K . Hatanaka, T. Inamura, Y. Yano, K.
Yamaguchi, and H. Kamitsubo: "The RIKEN SSC Beam Handling System," Proc.
5th Symp. Accelerator Science and Technology, Tsukuba, Sept., p. 184 (1984).
19) S. Nakajima, K. Ikegami, Y. Oikawa, S. H.
Be, and S. Motonaga: "Design of the Vacuum
System of the RIKEN SSC," Proc. 5th Symp.
Accelerator Science and Technology, Tsukuba, Sept., p. 229 (1984).
20) T. Wada, J. Fujita, K. Shimizu, I. Yokoyama,
and T. Kambara: "Control System of the
RIKEN SSC (I)," Proc. 5th Symp. Accelerator Science and Technology, Tsukuba,
Sept., p. 358 (1984).
21) T. Kambara and M. Odera: "Control System
of IPCR Heavy Ion Linac," Proc. 5th Symp.
Accelerator Science and Technology, Tsukuba, Sept., p. 364 (1984).
22) T. Shikata, N. Nakanishi, T. Kosako, andS. Fujita: "Radiation Shielding for the RIKEN SSC," Proc. 5th Symp. Accelerator
Science and Technology, Tsukuba, Sept.,
p. 391 (1984).
2. Nuclear physics and nuclear instrumentation
1) T. Nomura: "Evidence for Lower AngularMomentum Cutoff in Heavy-Ion Fusion
Reactions," JAERI-Symp. Heavy Ion Reactions, Tokai, Jan. (1984).
2) S. Yamaji: "Present Status of the Applicationof TDHF Theory to Heavy Ion Collisions,"
JAERI-Symp. Heavy Ion Reactions, Tokai,Jan. (1984).
3) S. Yamaji: "Effect of Two-Body Collisions
in TDHF," RIFP-Symp. Collective Motions, Kyoto, Jan. (1984).
4) H. Ohsumi, K. Okada, T. Shibata, Y. Nagai,
T. Motobayashi, and H. Ejiri: "Neutron
Decay Properties of Giant Quadrupole Resonance Region in 92Zr," Int. Symp. Nuclear
Spectroscopy and Nuclear Interactions, Osaka, Mar. (1984).

5) Y. Gono, M. Fukuda, M. Ishihara, T.
Inamura, T. Nomura, and H. Kamitsubo:"BGO Anti-Compton Spectrometer," 39th
Ann. Meeting Phys. Soc. J pn., Fukuoka,
Apr. (1984).
6) N . Yoshida, A. Arima, and T. Otsuka:"Description of High-Spin States in theInteracting Boson Model," 39th Ann. Meeting Phys. Soc. Jpn., Fukuoka, Apr. (1984).
7) K. Takeyama, K. Matsuta, K. Asahi,
Y. Nojiri, and T. Minamisono: "Nuclear
Spin Polarization of Short-Lived fi-Emitting
Nucleus Using Tilted Foil Technique," 39th
Ann. Meeting Phys. Soc. Jpn., Fukuoka, Apr.
(1984).
8) K. Matsuta, T. Minamisono, Y. Nojiri, andK. Asahi: "Energy Dependence of Anisotropy in ,8-decays of the A= 12 System,"
39th Ann. Meeting Phys. Soc. Jpn., Fukuoka,
Apr. (1984).
9) S. Yamaji and M. Tohyama: "Effects of Two
Particle-Two Hole Excitations on the Variances of Mass Distribution in the 160+40Ca
Reaction," 39th Ann. Meeting Phys. Soc.
Jpn., Fukuoka, Apr. (1984).
10) M. Sugawara, Y. Gono, T. Kubo, and M.
Fukuda: "In-Beam r-Ray Study of 212po,"39th Ann. Meeting Phys. Soc. J pn., Fukuoka,
Apr. (1984).
11) A. Hashizume, M. Ohshima, T. Inamura, E.
Minehara, S. Kikuchi, and H. Kumahora:"Ground State Rotational Band Excited by(58Ni, 58Ni')," 39th Ann. Meeting Phys.
Soc. Jpn., Fukuoka, Apr. (1984).
12) S. Yamaji and M. Tohyama: "Effects of Two
Particle-Two Hole Excitations on the Variances of Mass Distribution in the 160+40Ca
Reaction at E Lab =157.3 MeV," 1984 INSRIKEN Int. Symp. Heavy Ion Physics,
Yamanashi, Aug. (1984).
13) T. Nomura: "Low Angular-Momentum Cutoff in Heavy-Ion Fusion Reactions," 1984
INS-RIKEN Int. Symp. Heavy Ion Physics,
Yamanashi, Aug. (1984).
14) T. Nomura, K. Sueki, S. Kohmoto, H.
Kudo, K. Morita, T. Kubo, and M. Adachi:"Possible Existence of Low-Spin Cutoff in
Heavy-Ion Fusion Reactions," 1984 INSRIKEN Int. Symp. Heavy Ion Physics,
Yamanashi, Aug. (1984).
15) T. Nomura: "Sensitivity of Product Cross
Sections to Low Angular-Momentum Cutoff
in Fusion Reactions," 1984 INS-RIKEN
lnt. Symp. Heavy Ion Physics, Yamanashi,Aug. (1984).
16) T. Inamura: "Massive Transfer in Heavy

228

Ion Reactions," Invited Lecture at the 16th
Masurian Summer School on Nuclear Physics "Heavy Ions in Nuclear Physics," Mikolajki, Poland, Aug. (1984).
17) T. Murakami, J. Kasagi, H. Harada, H.
Tachibanaki, Y. Gono, and M. Fukuda:"B GO Crystal-as a High Energy r- Ray
Detector," 1984 Fall Meeting Phys. Soc.
Jpn., Mito, Sept. (1984).
18) H. Harada, T. Murakami, J. Kasagi, and T.
Inamura: "Excited States in llOSn Studied
with the 98Mo( 160, 4nr)llOSn Reaction,"
1984 Fall Meeting Phys. · Soc. J pn., Mito,
Sept. (1984).
19) Y. Gono, Y. Ishikawa, M. Sugawara, M.
Fukuda, and Y. Yoshikawa: "Spectroscopy of
218Ra Studied with BGOACS," 1984 Fall
Meeting Phys. Soc. Jpn., Mito, Sept. (1984).
20) T. Murakami, J. Kasagi, H. Harada, H.
Tachibanaki, Y. Gono, and M. Fukuda:"High-Energy r-Ray Detector of BGO,"
1984 Fall Meeting Phys. Soc. J pn., Mito,
Sept. (1984).
21) K. Sato: "Backward Angular Distribution in
the Generalized Exciton Model," 1984 Fall
Meeting Phys. Soc. Jpn., Mito, Sept. (1984).
22) K. Sueki, M. Magara, H. Nakahara, Y.
Hamajima, and 1. Kohno: "Heavy Particle
Emitting Reaction from 160+54Fe and
2oNe+ 50 Cr Systems," 1984 Fall Meeting
Phys. Soc. J pn., Mito, Sept. (1984).
23) H. Harada, M. Murakami, J. Kasagi, and T.
Inamura: "Study of Level Structure of llOSnby the 98Mo( 160, 4nr)llOSn Reaction," 1984
Fall Meeting Phys. Soc. Jpn., Mito, Sept.
(1984).
24) S. Kohmoto: "Tilted Foil Method by Thin
Foils," 1984 Fall Meeting Phys. Soc. Jpn.,
Mito, Oct. (1984).
25) Y. Hamajima, K. Sueki, M. Magara, H.
Nakahara, and 1. Kohno: "Mass Splittingof Lower Energy Fission," 28th Symp.
Radiochemistry, Kobe, Oct. (1984).
26) T. Nomura, S. Kohmoto, K. Morita, H.
Kudo, K. Sueki, M. Magara, and M. Adachi:"Search of Lower Critical Angular Momentum for Heavy-Ion Fusion Reaction," 28th
Symp. Radiochemistry, Kobe, Oct. (1984).
27) K. Sueki, M. Magara, H. Yoshikawa, Y.
Hatsukawa, H. Nakahara, Y. Hamajima, and1. Kohno: "Search of Fusion-Fission from
Compound Nucleus 70Se," 28th Symp.
Radiochemistry, Kobe, Oct. (1984).
28) M. Magara, K. Sueki, H. Nakahara, 1.
Kohno, H. Kudo, and Y. Hamajima: "HeavyIon Reaction between 14N +238U," 28th

Symp. Radiochemistry, Kobe, Oct. (1984).
29) T. Aoki, H. Garna, D. Price, Y. Sakamoto,and RFC Group: "Characterization of RF
Pulse Discharge Cleaning," Proc. 1st Fall
Meeting J pn. Soc. Plasma Physics andNuclear Fusion, Kanagawa, Oct., p. 96 (1984).
30) Y. Gono, M. Fukuda, Y. Ishikawa, M. Sugawara, T. Inamura, M. Ishihara, T. Nomura,
1. Kohno, H. Kamitsubo, J. Kasagi, and T.
Murakami: "RIKEN BGOACS System,"
Conf. Inst. Heavy-Ion Nuclear Research,
Oak Ridge, U.S.A., Oct. (1984).
3. Atomic and solid-state physics
1) T. Watanabe: "Electronic Structure of HighDensity Plasma III," Discussion Meeting
Theoretical Foundation for Pelet Design,
Katada, Jan. (1984).
2) K. Fujima and T. Watanabe: "Electronic
Structure of Cold N e Dense Plasma," 1984
INS Int. Symp. Heavy Ion Accelerators
and Their Applications to Inertial Fusion,
Tanashi, Jan. (1984).
3) T. Watanabe: "Electron Capture and Loss
Cross Sections in Atomic Collisions," 1984
INS Int. Symp. Heavy Ion Accelerators
and Their Applications to Inertial Fusion,
Tanashi, Jan. (1984).
4) S. Karashima and T. Watanabe: "Charge
Equilibrium of Fast Heavy Ions Traversing
Gaseous Media," 1984 INS Int. Symp. Heavy
Ion Accelerators and Their Applications toInertial Fusion, Tanashi, Jan. (1984).
5) T. Watanabe and K. Hino: "Theory of IonAtom Collisions at High Energy (I); NonRadiative and Radiative Electron Capture,"
J oint Seminar Atomic Physics, Solid State
Physics and Material Sciences in HighEnergy Region of Tandem Accelerators,
Tokai-mura, Jan. (1985).
6) S. Karashima and T. Watanabe: "Theory of
Ion-Atom Collisions at High Energy (II);Charge Equilibrium Processes," Joint Seminar Atomic Physics, Solid State Physics andMaterial Sciences in High Energy Region of
Tandem Accelerators, Tokai-mura, Jan.
(1985).
7) O. Kuboi, Y. Yatsurugi, H. Nagai, M. Aratani, M. Yanokura, S. Hayashi, 1. Kohno,
and T. Nozaki: "Studies of a-Si: H Growth
Mechanism by Distilling Exhaust Gas of
Glow Discharge Plasma," 31th Spring Meeting J pn. Soc. App!. Phys. and RelatedSocieties, Kawasaki, Mar. (1984).
8) A. Yunoki, S. Tamada, K. Masuda, A. Hitachi, J. Kikuchi, T. Doke, and T. Taka-

229

hashi: "LET Dependence of Scintillation
Light Yield from Liquid Argon and Xenon,"
31 th Spring Meeting J pn. Soc. Appl. Phys.
and Related Societies, Kawasaki, Mar. (1984).
9) K. Fukai, K. Shiraishi, S. Hamada, T. Sawai,
and E. Yagi: "Measurement of Mean Projected Range for Ar- and N-Ions Injected
into Stainless Steels," 1984 Ann. Meeting
At. Energy Soc. Jpn., Osaka, Mar. (1984).
10) Y. Kawabata, M. Utsuro, S. Okamoto, H.
Yoshiki, S. Hayashi, and T. Nozaki: "Elimination and Deuteration of Impurity Hydrogens on the Surface of Neutron Bottle
Materials," 1984 Ann. Meeting At. Energy
Soc., Osaka, Mar. (1984).
11) T. Tonuma, H. Shibata, S. H. Be, H. Kumagai, M. Kase, T. Kambara, 1. Kohno, and H.
Tawara: "Production of Secondary Ions by
Heavy Ion Impact," 39th Ann. Meeting
Phys. Soc. Jpn., Fukuoka, Mar. (1984).
12) K. Hino: "Radiative Electron Capture II,"
39th Ann. Meeting Phys. Soc. Jpn., Fukuoka,
Mar. (1984).
13) 1. Shimamura and A. C. Roy: "Rotational
Transitions between High Angular Momentum States of a Molecule-In the Case of
Symmetric Top Molecule," 39th Ann. Meeting Phys. Soc. Jpn., Fukuoka, Apr. (1984).
14) K. Nakanishi, K. Iguchi, A. Ohsaki, and T.
Watanabe: "The Calculation for (f.l+/F)
Production by Classical Trajectory Monte
Carlo Method," 39th Ann. Meeting Phys.
Soc. Jpn., Fukuoka, Apr. (1984).
15) K. Hino, T. Watanabe, and I. Shimamura:"The Theory of Radiative Electron Capture(REC)," 39th Ann. Meeting Phys. Soc. Jpn.,
Fukuoka, Apr. (1984).
16) S. Karashima and T. Watanabe: "Charge
State and Ranges of Incident Heavy Ions in
Matter," 39th Ann. Meeting Phys. Soc. Jpn.,
Fukuoka, Apr. (1984).
17) E. Yagi, T. Kobayashi, S. Nakamura, Y.
Fukai, and K. Watanabe: "Lattice Locationof Hydrogen in V," 39th Ann. Meeting Phys.
Soc. Jpn., Fukuoka, Apr. (1984).
18) E. Yagi, G. Flik, K. Furderer, N. Haas, D.
Herlach, J. Major, A. Seeger, W. Jacobs, M.
Krause, M. Krauth, H.-J. Mundinger, and
H. Orth: "Muon Diffusion in Iron," 39th
Ann. Meeting Phys. Soc. Jpn., Fukuoka,
Apr. (1984).
19) N. Sakai and H. Sekizawa: "Magnetic Compton Profiles of Fe Metal, Fe304 and MnFe204," 39th Ann. Meeting Phys. Soc. Jpn.,
Fukuoka, Apr. (1984).
20) K. Asai, T. Okada, and H. Sekizawa: "AStudy of MFe204 (M=Mn, Fe, Co, andMg) by TDPAC of r-Rays of 111Cd( +-111In)," 39th Ann. Meeting Phys. Soc. Jpn.,
Fukuoka, Apr. (1984).
21) K. Asai, F. Ambe, S. Ambe, T. Okada, and
H. Sekizawa: "Perturbed Angular Correlation of r-Rays Emitted from l11Cd ( +-- 111 In)
in a-Fe203," 39th Ann. Meeting Phys. Soc.
Jpn., Fukuoka, Apr. (1984).
22) T. Tonuma, S. H. Be, H. Kumagai, M. Kase,
H. Shibata, T . Kambara, H. Tawara, and I.
Kohno: "Measurements of Cross Sections
for Production of Secondary Ions by Heavy
Ion Impact," 39th Ann. Meeting Phys. Soc.
Jpn., Fukuoka, Apr. (1984).
23) H. Shibata, T. Matsuo, J. Urakawa, A. Yagishita, Y. Awaya, T. Kambara, M. Kase, H.
Kumagai, and J. Takahashi: "Measurementsof Ar L-MM Auger Electrons in Ar4 ++Ar
Collisions," 39th Ann. Meeting Phys. Soc.
Jpn., Fukuoka, Apr. (1984).
24) T. Kambara, Y. Awaya, M. Kase, H. Kumagai, H. Shibata, and S. M. Shafroth: "Kfj XRay Spectra of Ar-Ions Passing through Solid
Targets," 39th Ann. Meeting Phys. Soc.
Jpn., Fukuoka, Apr. (1984).
25) S. Sato, S. Tsurubuchi, K. Ando, H. Kumagai, S. Kohmoto, T. Tonuma, and Y. Awaya:"The Measurement of Sensitivity of Spectrometer Used for Beam-Foil Spectroscopy,"
39th Ann. Meeting Phys. Soc. Jpn., Fukuoka,
Apr. (1984).
26) H. Shibata, T. Matsuo, J. Urakawa, A. Yagishita, Y. Awaya, T. Kambara, M. Kase, H.
Kumagai, and J. Takahashi: "Measurementsof Ar L-MM Auger Electrons in Ar 4++Ar
Collisions," 39th Ann. Meeting Phys. Soc.
Jpn., Fukuoka, Apr. (1984).
27) T. Doke, T. Takahashi, and E. Shibamura:"Measurement of eDL/ f.l in Liquid Xe (III),"
39th Ann. Meeting Phys. Soc. Jpn., Fukuoka, Apr. (1984).
28) T. Takahashi, K. Masuda, Y. Awaya, T.
Tonuma, K. Izumo, A. Hashizume, A.
Hitachi, S. Uchiyama, and T. Doke: "Stopping Power of 5-7 MeV/amu He and C Ions,
Z1 3 Deviation from the Bethe Formula," 31th
Spring Meeting J pn. Soc. Appl. Phys. andRelated Societies, Kawasaki, Apr. (1984).
29) K. Aono, M. Iwaki, and S. Namba: Annealing of Ion-Implanted GaP (IV)," 31th Spring
Meeting J pn. Soc. Appl. Phys. and RelatedSocieties, Kawasaki, Apr. (1984).
30) K. Masuda, T. Takahashi, Y. Awaya, T.
Tonuma, K. Izumo, A. Hashizume, A.
Hitachi, S. Uchiyama, and T. Doke: "Z 13-

230

Dependence of Stopping Power for 5-7
MeVjamu He- and C-Ions," 31th Spring
Meeting J pn. Soc. Appl. Phys. and RelatedSocieties, Kawasaki, Apr. (1984).
31) S. M. Shafroth, Y. Awaya, T. Kambara, M.
Kase, S. Shibata, and H. Tawara: "Angular
Distribution of REC for Ar 4 + on C at 47.5
and 51.9 MeV," Washington Meeting Am.
Phys. Soc., Washington, U.S.A., Apr. (1984).
32) J. Nagakawa, H. Shiraishi, M. Okada, H.
Kamitsubo, I. Kohno, and T. Shikata:"Irradiation Creep of 316 Stainless Steel andEffect of Initial Microstructure," 94th Meeting J pn. Inst. Metals, N arashino, Apr.
(1984).
33) O. Kuboi, M. Hashimoto, Y. Yatsurugi, H.
Nagai, M. Aratani, S. Hayashi, M. Yanokura,
I. Kohno, and T. Nozaki: "Studies of aSi: H Growth Mechanism, Using Deuterium, by Rutherford Recoil Measurement,"
17th IEEE Photovoltaic Specialists Conf.,
Orland (Florida), U.S.A., May (1984).
34) T. Watanabe: "Atomic Structure of HighDensity Plasma," Meeting of Working Groupon Atomic Structure of High Density Plasma,
Nagoya, May (1984).
35) E. Yagi: "Diffusion of Positive Muons inIron," Res. Inst. Fundamental Phys. Kyoto
Univ. Symp. Charged Particle Motion in
Metals, Kyoto, June (1984).
36) Y. Fukai, K. Watanabe, E. Yagi, S. Nakamura, and T. Kobayashi: "4T State of Hydrogen in V," Symp. Refractory Metals,
Kawato, June (1984).
37) A. Ohsaki, T. Watanabe, K. Nakanishi, andK. Iguchi: "Classical Trajectory Monte Carlo
Calculation for p+ + ClCp) --+ (p +p-)+p ande++(e- p)-(e+e-)+p," 9th Int. Conf. Atomic
Physics, Seattle, U.S.A., July (1984)38) Q. Ma, X. Chang, Z. Liu, Y. Liu, and T.
Watanabe: "Distorted Wave Born Cross
Section for p+ + (p-p) --+ (p +p-)+p," 9thInt. Conf. Atomic Physics, Seattle, U.S.A.,
July (1984).
39) S. Karashima, T. Watanabe, X. Chang, Z.
Liu, Q. Ma, and Y. Liu: "Electron Stripping
Cross Section on Multiply Charged Ions by
Collision with Neutral Atoms," 9th Int.
Conf. Atomic Physics, Seattle, U.S.A., July
(1984).
40) A. C. Roy and 1. Shimamura: "Transitionsof Molecules between High Rotational
States," 9th Research Meeting Soc. for
Atomic Collision Research (Japan), Wako,
July (1984).
41) A. Ohsaki and T. Watanabe: "Where is

Difficult for the Calculation of Positronium
Formation," 9th Research Meeting Soc. for
Atomic Collision Research (Japan), Wako,
July (1984).
42) T. Tonuma, S. H. Be, H. Kumagai, H.
Shibata, M. Kase, T. Kambara, I. Kohno,
and H. Tawara: "Ionization of He, Ne and
Ar Atoms by 1.05 MeVjamu CH (q=2-6)
and ArH (q=4-14) Ion Impact," Int. Conf.
Physics of Highly Ionized Atoms, Oxford,
England, July (1984).
43) T. Tonuma, S. H. Be, H. Kumagai, H.
Shibata, M. Kase, T. Kambara, I. Kohno,
and H. Tawara: "Multiple Ionization ofAtoms by Highly Ionized Heavy Ion Impact,"
Int. Conf. Physics of Highly Ionized Atoms,
Oxford, England, July (1984).
44) K. Maeda, Y. Hayashi, and M. Uda: "Oxygen K Emission Spectrum Free from Multiple-Vacancy Satellite," Int. Conf. X-Ray andInner-Shell Processes in Atoms, Molecules
and Solids, Leipzig, E. Germany, Aug.
(1984).
45) Y. Awaya, T. Kambara, M. Kase, H. Kumagai, H. Shibata, and S. M. Shafroth: "Multiple Inner-Shell Ionization of Ar Ions Passing through Foils," Int. Conf. X-Ray andInner-Shell Processes in Atoms, Molecules
and Solids, Leipzig, E. Germany, Aug.
(1984).
46) M. Uda, A. Koyama, K. Maeda, and Y. Sasa:"Valence Electron Rearrangement Prior to
X-Ray or Auger Electron Emission," Int.
Conf. X-Ray and Inner-Shell Processes inAtoms, Molecules and Solids, Leipzig, E.
Germany, Aug. (1984).
47) Y. Awaya: "Multiple Inner-Shell Ionizationof Heavy Ions Passing thr:ough Foils,"
Brasov Int. School, Atomic and Nuclear
Heavy Ion Interactions, Brasov, Rumania,
Aug. (1984).
48) M. U da: "Chemical Effects in Characteristic
X-Ray Emitted from Multiply IonizedStates," Brasov Int. School, Atomic andNuclear Heavy Ion Interactions, Brasov,
Rumania, Sept. (1984).
49) Y. Sakamoto, H. Oyama, and S. Kakinuma:"ECR Discharge Cleaning Device with
Permanent Magnet," Proc. 25th Vacuum
Symp., Osaka, Oct., p. 127 (1984).
50) K. Okazaki, A. Minoh, S. Ishii, Y. Ishibe, H.
Oyama, Y. Sakamoto, and K. Yano: "LIFS
Measurements of Sputtering Particle Densities by Plasma Irradiation," Proc. 25th
Vacuum Symp., Osaka, Oct., p. 129 (1984).
51) H. Oyama, S. Kakinuma, and Y. Sakamoto:231"Interaction of Titanium Oxide with Hydrogen Plasma," Proc. 25th Vacuum Symp.,
Osaka, Oct., p. 135 (1984).
52) Q. Ma, X. Chang, Z. Liu, Y. Liu, and T.
Watanabe: "The Distorted Wave Born Calculation for P++(,lCp) --» (p +p-)+p," 1984
Fall Meeting Phys. Soc. Jpn., Toyama, Oct. (1984).
53) S. Karashima, H. Kawagoshi, and T. Watanabe: "The Electron Stripping Cross Sectionof Incident Multiply Charged Ion by ManyElectron Target Atom," 1984 Fall Meeting
Phys. Soc. Jpn., Toyama, Oct. (1984).
54) S. Karashima, H. Kawagoshi, T. Watanabe,
Y. Liu, X. Chang, Z. Liu, and Q. Ma: "TheElectron Stripping Cross Section of Multiply
Charged Ion by BEA," 1984 Fall Meeting
Phys. Soc. Jpn., Toyama, Oct. (1984).
55) M. Sekiya, T. Noro, F. Sasaki, and K. Ohno:"Auger Energies of Ar 6 + L z3 -M IM I and
Their Relative Transition Probabilities,"
1984 Fall Meeting Phys. Soc. Jpn., Toyama,
Oct. (1984).
56) M. Uda and A. Koyama: "Chemical Effects
on AES Induced by Ions," 1984 Fall Meeting
Phys. Soc. Jpn., Toyama, Oct. (1984).
57) K. Ando, S. Komoto, T. Tonuma, H. Kumagai, Y. Awaya, S. Tsurubuchi, and K. Sato:"Analysis of Beam-Foil Spectra of Highly
Ionized Aluminum," 1984 Fall Meeting
Phys. Soc. Jpn., Toyama, Oct. (1984).
58) Y. Kawabata, M. Utsuro, S. Okamoto, H.
Yoshiki, S. Hayashi, and T. Nozaki: "Measurements of the Impurity Hydrogen Concentration on the Surface of the Materials for
Neutron Bottle," 1984 Fall Meeting Atomic
Energy Soc., Tokai, Oct. (1984).
59) K. Ando, T. Tonuma, S. Kohmoto, H.
Kumagai, Y. Awaya, S. Tsurubuchi, and K.
Sato: "Analysis of Spectra of Highly IonizedAluminum Atoms Obtained by Beam-Foil
Spectroscopy," 1984 Fall Meeting Phys. Soc.
Jpn., Toyama, Oct. (1984).
60) E. Vagi, S. Nakamura, T. Kobayashi, K.
Watanabe, Y. Fukai, F. Kano, S. Seguchi,
and K . Watanabe: "Lattice Location of H
in Nb," 1984 Fall Meeting Phys. Soc. Jpn.,
Toyama, Oct. (1984).
61) N. Sakai and H. Sekizawa: "Computer
Simulation of the Energy Spectrum of SpinDependent Doubly Compton Scattered
Gamma-Rays," 1984 Fall Meeting Phys. Soc.
J pn., Toyama, Oct. (1984).
62) T. Okada, K. Asai, and H. Sekizawa: "AStudy of MFe z04 (M=Mn, Fe, Co, and Mg)
by TDPAC of r-Rays of 11ICd (+- 111In)(II)," 1984 Fall Meeting Phys. Soc. Jpn.,
Toyama, Oct. (1984).
63) K. Asai, F. Ambe, S. Ambe, T. Okada, and
H. Sekizawa: "Perturbed Angular Correlation of r-Rays Emitted from 111Cd (+- 111 In)
in a-Fez03 (II)," 1984 Fall Meeting Phys.
Soc. Jpn., Toyama, Oct. (1984).
64) T. Okada, K. Asai, F. Ambe, and H. Sekizawa: "111In TDPAC in Ferrite," 1984 Fall
Meeting Phys. Soc. Jpn., Toyama, Oct.
(1984).
65) M. Fujinaga, K. Asahi, Y. Nojiri, and T.
Minamisono: "NMR of the Short-lived f3emitter 12B in Single Crystal Ta," 1984 Fall
Meeting Phys. Soc. Jpn., Toyama, Oct.
(1984).
66) T. Iwayama, Y. Nojiri, K. Asahi, and T.
Minamisono: "Hyperfine Interactions of
Short-Lived f3-Emitter 12N in Single Crystal
Fe," 1984 Fall Meeting Phys. Soc. Jpn.,
Toyama, Oct. (1984).
67) K. Asahi, F. Ambe, S. Ambe, T. Okada, and
H. Sekizawa: "TDPAC of 1Hln in Fe203,"
28th Symp. Radiochemistry, Kobe, Oct.
(1984).
68) K. Ikeda, N. Ito, T. Aimi, S. Hayashi, M.
Yanokura, I. Kohno, T. Nagai, M. Aratani,
and T. Nozaki: "Application of Heavy-Ion
Probe RBS to the Analysis of Si Ohmic
Contact Systems," 28th Symp. Radiochemistry, Kobe, Oct. (1984).
69) S. Kakinuma, H. Oyama, and Y. Sakamoto:"Ti Surface Control by Hydrogen Plasma,"Proc. 1st Fall Meeting J pn. Soc. Plasma
Phys. and Controlled Fusion, Tokai Univ.,
Kanagawa, Oct., p. 115 (1984) .
70) K. Maeda, Y. Yokode, H. Kusuyama, Y.
Sasa, and M. Uda: "Application of PIXE toMedical Science," 20th Tokyo Symp.
Applied Spectrometry, Tokyo, Nov. (1984).
71) K. Maeda, Y. Sasa, M. Maeda, and M. Uda:
"Diagnosis of Environment by PIXE," 20th
Tokyo Symp. Applied Spectrometry, Tokyo,
Nov. (1984).
72) K . Ando, S. Kohmoto, T. Tonuma, H. Kumagai, Y. Awaya, S. Tsurubuchi, and K. Sato:"Beam-Foil Spectroscopy of Highly IonizedAluminum Atoms," US-Japan Workshop on
Tokamak Diagnostics by X-Ray, VUV, andOptical Radiation, Nagoya, Nov. (1984).
73) Y. Awaya: "Target Atomic Number Dependence of Simultaneous K-Shell and L-Shell
Ionization of Projectile Heavy Ions," 8thConf. on the Application of Accelerator in
Research and Industry, Denton (Texas),
U.S.A., Nov. (1984).

23274-) Y. Awaya, S. Karashima, T. Watanabe, and
Y. Liu: "Electron Stripping Cross Section
from Multiply Charged Ions by Neutral
Atoms," 2nd Int. Workshop on Cross Sections for Fusion and Other Applications,College Station (Texas), U.S.A., Nov. (1984-).
75) K. Shiraishi, K. Fukai, E. Yagi, T. Sawai, and
S. Hamada: "Depth-Dependent Damage Profile in Stainless Steels Irradiated with Ar- andN-Ions," 1st Int. Conf. on Fusion Reactor
Materials, Tokyo, Dec. (1984-).
76) J. Nagakawa, H. Shiraishi, M. Okada, H.
Kamitsubo, I. Kohno, and T. Shikata:"Irradiation Creep Simulation under Low
Proton Flux," 1st Int. Conf. on Fusion
Reactor Materials, Tokyo, Dec. (1984-).
77) N. Yamamoto, H. Shiraishi, H. Kamitsubo,
I. Kohno, T. Shikata, and A. Hishinuma:"Effects of TiC Distribution on the Creep
Properties of Helium Injected JPCA," 1stInt. Conf. Fusion Reactor Materials, Tokyo,
Dec. (1984-).
78) T. Takahashi and T. Doke: "Comment on
the Track Formation and Scintillation Light
Yield in Liquid Rare Gases," Workshop on
the Interaction of Ion Beam with Solids,
Nagoya, Dec. (1984-).
79) T. Watanabe: "Theory for Characteristic
Radiation Interaction by Heavy Ion Impact,"
Riken Symp. Interaction of Heavy Ions withMatter, Wako, Dec. (1984-).
4-. Radiochemistry, radiation chemistry and radiation biology
1) T. Takahashi, F. Yatagai, I. Kaneko, T.
Katayama, Y. H. Kang, A. Yunoki, S. Konno,
and S. Okada: "Detection of Argon Ions by a
Plastic Detector and Fraction of Dead Spores
as a Function of Impact Parameter," 31th
Spring Meeting J pn. Soc. App!. Phys. andRelated Societies, Kawasaki, Apr. (1984).
2) Y. Itoh, T. Nozaki, T. Masui, and T. Abe:
"Oxygen Concentration in Heavily Doped
Silicon," 31th Spring Meeting J pn. Soc.
App!. Phys. and Related Societies, Tokyo,
Apr. (1984-).
3) F. Ambe, S. Ambe, T. Okada, and H. Sekizawa: "In situ Emission Mossbauer Spectroscopy of 119Sb5 + at the a-Fe203-Aqueous
Solution Interfaces," 49th National Meeting
Chern. Soc. J pn. (Spring), Tokyo, Apr.
(1984).
4-) S. Hayashi, H. Nagai, M. Aratani, T. Nozaki,
M. Yanokura, I. Kohno, O. Kuboi, and Y.
Yatsurugi: "High Sensitivity Analysis ofDeuterium in Solids by 15N-Induced Nuclear

Reactions," 8th Symp. Ion Sources and IonAssisted Technology, Tokyo, June (1984-).
5) M . Yanokura, M. Aratani, H. Nagai, S.
Hayashi, I. Kohno, T. Nozaki, O. Kuboi, andY. Yatsurugi: "The Heavy-Ion Probe
Rutherford Scattering Analysis Applied to
the Study of Electronic Materials," 8th Symp.
Ion Sources and Ion-Assisted Technology,
Tokyo, June (1984-).
6) K. Fukushi, T. Irie, O. Inoue, T. Yamasaki,
and T. Nozaki: "6-Halo-9-Benzylpurines as
Carriers of Various Radiohalogen Ions into
Brain," 5th Int. Symp. Radiopharmaceutical
Chemistry, Tokyo, July (1984).
7) T. Hara, T. Nozaki, T. Karasawa, M. lio, andR. Izuchi: "(l1C)-l-Glucose and Mannose asSpecific Tumor Markers," 5th Int. Symp.
Radiopharmaceutical Chemistry, Tokyo,
July (1984).
8) K. Eguchi, I. Kaneko, and T. Inada: "DNA
Damage and Its Repair in Human Tumor
Cells by Heavy Ions," Riken Symp. DNA
Lesion, Tokyo, July (1984).
9) T. Takahashi, F. Yatagai, I. Kaneko, T.
Katayama, and K. Matsuda: "Dosimetry of
Heavy Ions and Inactivation of B . . subtilis
Spore by a Single Heavy Ion," 27th Ann.
Meeting Jpn. Radiat. Res. Soc., Chiba, Sept.
(1984-).
10) I. Kohno, M. Yanokura, S. Motonaga, H.
Kamitsubo, T. Suematsu, H. Kobayashi, andM. Yatsuhashi: "Irradiation of Insulating
Materials for Cable by Fast Neutron (I),"1984 Fall Meeting Atomic Energy Soc. J pn.,
Tokai, Oct. (1984).
11) T. Suematsu, H. Kobayashi, M. Yatsuhashi,
I. Kohno, M. Yanokura, S. Motonaga, and
H. Kamitsubo: "Irradiation of Insulating
Materials for Cable by Fast Neutron (II),"
1984 Fall Meeting Atomic Energy Soc. J pn.,
Tokai, Oct. (1984-).
12) K. Kimura: "Unusual Emission Spectra of
Liquid Helium Impinged by Heavy Ions I,"
1984 Spring Meeting Phys. Soc. J pn., Fukui,Oct. (1984).
13) K. Kimura: "Unusual Emission Spectra of
Liquid Helium Impinged by Heavy Ions II,"
1984- Fall Meeting Phys. Soc. J pn., Toyama,
Oct. (1984).
14-) H. Nagai, M. Aratani, S. Hayashi, T. Nozaki,
M. Yanokura, I. Kohno, O. Kuboi, andY. Yatsurugi: "Rutherford Forward Scattering Applied to the Analysis of Hydrogen(III)," 28th Symp. Radiochemistry, Kobe,
Oct. (1984-).
15) S. Hayashi, H. Nagai, M. Aratani, T. Nozaki,

233
M. Yanokura, 1. Kohno, O. Kuboi, ·and Y.
Yatsurugi: "High Sensitivity Analysis ofDeuterium in Solids by 15N-induced Nuclear
Reactions," 28th Symp. Radiochemistry,
Kobe, Oct. (1984).
16) F. Ambe, S. Ambe, T. Okada, and H. Sekizawa: "In situ .Emission Mossbauer Sp.ectraof 119Sb Adsorbed on the Surfaces of aFe20a and r-Fe20a," 28th Symp. Radiochemistry, Kobe, Oct. (1984).
17) K. Kimura, T. Azuma, Y. Aoki, and Y. I to:"Unusual Emission Spectra of Liquid Helium
Impinged by Heavy Ions," 27th Conf.
Radiation Chemistry, Tokyo, Oct. (1984).
18) Y. Aoki, T. Azuma, Y. Katsumura, Y. Tabata, Y. Ito, and K. Kimura: "Single-Photon
Counting of Fluorescence Induced by Heavy

Ions," 27th Conf. Radiation Chemistry, Tokyo, Oct. (1984).
19) F. Ambe: "Mossbauer Spectroscopy of Metal
Ions Adsorbed on Surfaces of Magnetic
Material and Its Applications," 1984 Int.
Chern. Congr. Pacific Basin Soc., Honolulu(Hawaii), U.S.A., Dec. (1984).
20) H. Kudo, T . Nomura, K. Sueki, and M.
Magara: "Isomeric Transitions of 211mpo
and 212mpo," '1984 Int. Chern. Congr. PacificBasin Soc., Honolulu (Hawaii), U.S.A., Dec.
(1984) . .
21) T. Takahashi, K. Eguchi, T. Katayama, and
1. Kaneko: "Track Structure Theories andBiological Effect of Heavy Ions," Symp. ofInteraction of Heavy Ion with Matter, Wako,
Dec. (1984).

,~

234

VIII.

LIST OF OUTSIDE USERS AND THEIR THEMES(Jan.- Dec. 1984)
1)

T. Kimura"Radiochemical Analysis of 160, 14N
and HC in Si Crystal and GaSb"

Japan Chemical Analysis Center2)

H. Ueyama"Study of Effect by Bombarding HighEnergy Proton on a Si Solar Cell"

Sharp Co., Ltd.

3)

H. Nakahara"Production of 1251 and 131Xe"

Faculty of Science, Tokyo
Metropolitan Univ.

4)

S. Orito and S. Nakamura"Test of Sensibility of CR39 Track
Detector for High Energy Proton"

Faculty of Science, Univ. of Tokyo

5)

H. Homareda"Production of 43K"

Faculty of Medicine,
Kyorin Univ.

6)

S. Suzuki"Study of Effect by Bombarding
High Energy Proton on a Solid
Fuel for a Rocket"

Space Development Div.,
Nissan Automobile Co., Ltd.

7)

H. Shinyashiki and M. Takeya"Radiochemical Analysis of 160
in GaAs"

Central Res. Lab., Mitsubishi
Metal Co., Ltd.

8)

H. Yamamoto"Radiation Damage of Cover Glass fora Solar Cell"R&D Div., Asahi Glass Co., Ltd.

9)

M. Yatsuhashi and T. Suematsu"Study of Effect by Irradiating Fast
Neutron on a Insulator Covering a
Cable"

Fujikura Cable Works~ Ltd.

235

IX.

LIST OF SEMINARS(Jan.-Dec. 1984)
1) D. Bohne, GSI (West Germany), 2 February"Present Situation and Future Plans of
UNILAC (GSI)"

12) A. Ikeda, Tokyo lnst. Tech. (Tokyo), 17 April"Effects of r- Vibration on High-j RotationalBands"

2) P. Lapostolle, GANIL (France), 3 February"Present Situation at GANIL"

13) H. Morinaga, Tech. Univ. Miinchen (WestGermany), 24 April"Energy Transfer in Heavy Ion Transfer
Reactions' ,3) H. Sakamoto, Univ. of Tsukuba (Ibaraki), 21
February"Present Status and Future Image of Data
Processing System for Nuclear Experiments"
4) T. A. N. Miller, Indiana Univ. (USA), 23
Februaryi) "Current Studies at IUCF"ii) "Facility Developments at IUCF"
5) K. Tanabe, Saitama Univ. (Saitama), 29
February"Nuclear Structure of High-Excited HighSpin States"

6) G. Bruge, Saclay (France), 27 March"p- Nucleus Experiments"
7) A. Gelberg, Univ. zu Koln (West Germany),
28 March"Two-Quasiparticle States in Xe, Ba, andCe Nuclei"

8) B. Herskind, Niels Bohr Inst. (Denmark), 28
March"Anti-Compton Ge-Detector Array andStudy of High-Spin States"
9) F. Touchard, Orsay (France), 29 March"Laser Spectroscopy of Radioactive Atomic
Nuclei"10) O. Hashimoto, INS (Tokyo), 11 April"Experiments and Data Processing System
at BEVALAC"
11) J. Kasagi, Tokyo Inst. Tech. (Tokyo), 11 April"Experiments and Data Processing System
at MSU"14) J. Chiba, Univ. of Tokyo (Tokyo), 1 May"On-Line Data Processing System at KEK"
15) K. Nagamine, Univ. of Tokyo (Tokyo), 22 May"p-Production by Heavy Ion Beam and Its
Many-Fields Application"16) H. P. Blok, Vrigh Univ. Amsterdam (Holland),
29 May"Recent (e, e') and (e, e' p) Results at the
Amsterdam Electron Accelerator"
17) T. Motobayashi, St. Paul Univ. (Tokyo), 17
July"d- 2He Reaction on Light Nuclei"18) H. Tanabe, Univ. of Tokyo (Tokyo), 31 July
"Role of LI in Pion Photoproduction"19) T. Tamura, Univ. of Texas (USA), 20 August"Heavy-Ion Fusion (Subthreshold, above
Threshold)"20) J. D. Garrett, Niels Bohr lnst. (Denmark), 1
September"Pair Phase Transitions"21) V. Metag, Univ. Giessen (West Germany), 1
September"Crystal Ball"
22) G. Miinzenberg, GSI (West Germany), 1
September"Heaviest Elements"23) S. Chojnacki, Warsaw Univ./Dubna (Poland),13 November"Mechanism of a-Particle Emission in the
160+232Th Reactions"x.

LIST OF PERSONNEL

Members of the Board
AWAYA Yohko ~ ~ '$.:r
HA.SHIZUME Akira ;mfj JR M
ISHIHARA Masayasu :;P JJj( lE ~KIRA Akira "15 & ~NOZAKI Tadashi If IIffif lE
OKADA Shigefumi . WiJ m:m X
SAKAMOTO Yuichi !OC it SHIMA Makoto 9h~*
UDA Masayuki !¥ m~ z
YOSHIDA Kiyota "15 m~*

CHIBA Yoshiaki =f frJ ijJi
. IMAMURA Masashi 4-;ft ~*KAMITSUBO Hiromichi J: W ~ it!
KOHNO Isao M if ~ODERA Masatoshi Ij" ~ lE ~SAKAIRI Hideo !OC :A ~ at
SEKIZAWA Hisashi 00 tR MJSHIOTANI Nobuhiro :!i[:§ If. "5.&*WATANABE Tsutomu** through March 31, 198411**** chairman

Cyclotron Operation and Maintenance Group
FUJITA Shin jfj m ff
KAGEYAMA Tadashi ' l6 I-U lE
KOHNO Isao M if ~T AKEBE Hideki m; 1m ~ m

Linac Operation and Maintenance GroupCHIBA Yoshiaki =f frJ ijJi
IKEZAWA Eiji ~ tR ~KAMBARA Tadashi 1$))j( lE
KUBO Toshiyuki ~ 1* fii!{ of:YANOKURA Minoru fRif:;@j- ~

*

~ 1m

=

. , IKEGAMI Kumio~J:jL=:Jij

KOHARA Shigeo Ij" JJj( :m :k
OG IWARA Kiyoshi ~ JJj( ~ .

HEMMI Masatake ~ ~ ~ m;
INOUE Toshihiko # 1: 4!i;t fJ;
KASE Masayuki no ~ ~ Z
MIYAZAWA Yoshitoshi '§ tR tE 4!i;t

Scientific and Engineering Personnel

Cyclotron Laboratory
BE Suck Hee n 1i1i:@:
FUJITA Jiro jff m ll!~
HARA Masahiro ))j( ~"5.&
INAMURA Takashi fili;ft .$:KARASAWATakashitR' ~MORITA Kohsuke ~ mr~ 11NAGASE Makoto ~ ~ ~NAKANISHI Noriyoshi q:t gg ~

=

m

*

, FUJISAWA Takashi jfj tR iWi ~GOTO Akira 1ft jfj ~HATANAKA Kichiji ~ q:t "15 ri:i .
KAMITSUBO Hiromichi 1: W ~ it!
KOHNO Isao M if ~MOTONAGA Shoshichi 5G 7k lIN t
NAKAJIMA Shunji q:t Nh ~NOMURA Toru If;ft :rjr

=

237

*-

a

OIKAWA Yoshifumi ~ )11
fl~
SHIKAT A Takashi 129 jj [i 51::
TAKESHITA Isao 1"1" r ~ X:
YAMAJI Shuhei 1lJ.Im {~ ~YOKOYAMA Ichiro ~ IlJ - ~~SAKAMOTO Ichiro !&:~~SHIMIZU Kazuo ~ 7k 5f1l ~WADA Takeshi 5f1l m at
YAN 0 Yasushige fR.!lf :m
YOSHIDA Nobuaki tf III g •*(Visitors)
AUGER Pierre (CSNSM, Orsay)
FURUNO Kohei 11 !If ~ ~ (Inst. Phys., Univ. of Tsukuba)
IEKI Kazuo~ 5f1l X: (Dept. Phys., Tokyo Inst. Tech.)
INOUE Makoto it L{~ (RCNP, Osaka Univ.)
KAMIMURA Masayasu 1:;ft lE ~ (Dept. Phys., Kyushu Univ.)*

KASAGI Jirota ~*ra~~* (Dept. Phys., Tokyo Inst. Tech.)
KATORI Kenji 1.& 1& ~(Dept. Phys., Osaka Univ.)
KIKUCHI Fumio ~ t& Jt ~ (Dept. Math., College of General Education, Univ. of Tokyo)=m*

KOHMOTO Susumu)1§
KUDO Hisaaki I hi ~ II8 (Dept. Chern., Niigata Univ.)
MORINAGA Haruhiko ~ 7k P'A' ~ (Dept. Phys., Technische Universitat Munchen)
MOTOBAYASHI Toru
1*
(Dept. Phys., Rikkyo Univ.)
MURAKAMI Takeshi # L~ (Dept. Phys., Tokyo Inst. Tech.)
NAGAKAWA Johsei 7k)1I ~ lE (Nat. Res. Inst. for Metals)
NAGAMIYA Shoji 7k '8 lE(Dept. Phys., Univ. of Tokyo)
NAKAHARA Hiromichi t:p~k iR (Dept. Chern., Tokyo Metropolitan Univ.)
ONISHI Naoki
IDf Wi ~ (Phys. Inst., College of General Education, Univ. of Tokyo)
ROMMEL G. (GANIL, France)
ROY Amulya C. (Dept. Phys., Univ. of Kalayani)
SATO Kenichi {£ hi. - (Division Phys., Tohoku College of Pharmacy)
SHIRAISHI Haruki S;P W. (Nat. Res. Inst. for Metals)
TAKADA Eiichi ~ m(Dept. Phys., Kyoto Univ.)
TAKEMASA Tadashi lEt ~ jT ± (Dept. Phys., Saga Univ.)
WHITTEN C. A. Jr. (Dept. Phys., Univ. of California)

*

m

ra

'*

*

*
*-

* 5f1l (Nat. Res. Inst. for Metals)

YAMAMOTO Norikazu IlJ
YOSHIDA Shiro tf m,~~~1ffff.

(Dept. Phys., Tohoku Univ.)(Students)
ENOMOTO Masato tl $t A (Fac. Sci. and Eng., Chuo Univ.)
HARADA Hideom~ ~~ (Dept. Phys., Tokyo Inst. Tech.)
NAKAMURA Masami t:p # lE ~ (Fac. Sci. and Eng., Chuo Univ.)
SHIMOMURA Hideo r # ~ it (College of Hum. and Sci., Nihon Univ.)
SUEKI KeisukeF,§ 1r (Dept. Chern., Tokyo Metropolitan Univ.)
TACHIBANAKI Hiroshi fi
Jt (Dept. Phys., Tokyo Inst. Tech.)
YAMAGUCHI Kazuya IlJ 1=1 5fll ill (College of Hum. and Sci., Nihon Univ.)

'*

*

**

Linac Laboratory
CHIBA Toshiya =f ~ ;fIJ =tDt*

CHIBA Yoshiaki =f ~ !if ~238

GONO Yasuyuki ~~:I.I i'$ Z
HOSHINO Kiichi £ lit ~ ISHIKAWA Yoshiharu -;P)I[ ~ Rl!!
KASE Masayuki ][]. l§ z
MIYAZAWA Yoshitoshi '8 rR {* ~ODERA Masatoshi IJ'\ ~ IE ~TONUMA Tadao F' mIE it

HEMMI Masatake ~ j! ~ -IT;tINOUE Toshihiko # 1: ~ ffi
KAMBARA Tadashi f$ ~ IE
KUBO Toshiyuki~ =$MIZOGAWA Tatsumi $)1[ ~ a!A *SHIBATA Hiromi ~ IE m~
YANOKURA Minoru ~!I!f~~(Visitors)
FUJIWARA Ichiro JJi ~ - ~~ (Inst. Atomic Energy, Kyoto Univ.)$ BE ~ (Dept. Phys., Tohoku Univ.)
HAYASHIBE Shogo
ITO Noriaki {Jt JJi ;I; BE (Dept. Crystalline Materials, Nagoya Univ.)
MATSUO Takashi t~ ~(Tokyo Medical and Dental Univ.)
MORITA Susumu ~ IE ti (College of Eng., Hosei Univ.)ODA Nobuo ~~ IE ~:k (Res. Lab. for Nucl. Reactors, Tokyo Inst. Tech.)OTANI Shunsuke *:{t ~:ft (Inst. Plasma Phys., Nagoya Univ.)
SUGAWARA Masahiko if ~ ~ ffi (Fund. Sci., Chiba Inst. Tech.)SUZUKI Hiroshi ~;;1( ~ (Dept. Phys., Sophia Univ.)
TAWARA Hiroyuki
iW Z (Inst. Plasma Phys., Nagoya Univ.)
URAKAWA Junji 00 )IIII/ri fr3 (Nat. Lab. High Energy Phys.)
YAGISHITA Akira :fgp r~ (Nat. Lab. High Energy Phys.)

**

*

*

(Student)
FUKUDA Mitsunori

mIE :yc JIIfi (Fac. Sci., Tokyo lnst. Technol.)Radiation Laboratory
ASAHI Koichiro :h§. *)f- ~~ISHIHARA Masayasu -;p ~ IE ~KONNO Satoshi ~ lit ~OHSUMI Hideaki
TAKAHASHI Tan*~ Jfj ~~ ~li

HASHIZUME Akira ~ JT\ M
IZUMO Koichi t±l ~ :yc KUMAGAI Hidekazu 1m:{t Jfj foo KA.N 0 Masaharu WiJ lit J'{ 1fi
TENDOW Yoshihiko ;R. 7i ffi(Visitors)
DOKE Tadayoshi Jl! lID ~ (Sci. and Eng. Res. Lab., Waseda Univ.)
FUJIOKA Manabu Hi WiJ $. (Dept. Phys., Tohoku Univ.)
HASEGAWA Takeo *:{tJII-IT;t:k (Inst. Nucl. Study, Univ. of Tokyo)
HITACHI Akira JJ t±l :!if (Sci. & Eng. Res. Lab., Waseda Univ.)
no Masahiro ~ IE rt. (Fac. Med., Univ. of Tokyo)
KANG Yung-Ho ~ ~ r~ (Dept. Natural Sci., Kyung-Pook Univ.)
KIM Do Sung ~ Jl! M (Dept. Natural Sci., Kyung-Pook Univ.)
KOBAYASHI Hisanobu IJ'\{~ (Fac. Eng., Saitama Univ.)
KUBOTA Shinzou fi IE {~.:::: (Fac. Sci., Rikkyo Univ.)
LEE Sang Mu :$ ;f§(Univ. Tsukuba)
MASUDA Kimiaki :It m ~ (School Sci. Eng., Waseda Univ.)
MIURA Taichi .:::: 00(Dept. Chern., Tokyo Metropolitan Univ.)

*

m

**!A

m

*

*-

m

239

MOTOBAYASHI Toru ;;$: 1* ~ (Fac. Sci., Rikkyo Univ.)
MURAMATSU Hisakazu ;f:;f t~!A fo (Nat. Lab. High Energy Phys.)
NAGAHARA Teruaki 7k me P.« ~ (Inst. Atomic Energy, Rikkyo Univ.)**

OHTSUKA Hideko~ ~T
OHTSUKA Rikuro~ ~ E!~ (Nagoya Inst. Technol.)
ONAI Yoshio ~ r"J RIg;k (Dept. Phys., Cancer Inst.)
SHIBAMURA Eido ~;f:;f ~ m (Saitama College of Health)(Students)
HATSUKAWA Yuichi 19])11 it ~ (Dept. Chern., Tokyo Metropolitan Univ.)
SUZUKI Satoshi ~Iff. (School Sci. Eng., Waseda Univ.)
YANAGA Makoto
7k ~ A (Dept. Chern., Tokyo Metropolitan Univ.)
YUNOKI Akira fIB~ (School Sci. Eng., Waseda Univ.)***

Atomic Processes Laboratory*-=

ANDO Kozo
Hi IMJIJNISHIDA Masami W IE ~ ~SHIMAMURA Isao Si;f:;f ~AWAYA Yohko ~.m~T
OHSAKI Akihiko(!ffif ~ fj;
WATANABE Tsutomu ~ ~~*11

(Visitors)
FUJIMA Kazumi Hi r~' ~ *- (Dept. Phys., Chuo Univ.)
HARA Shunsuke me ~ 1r (Dept. Phys., Univ. of Tsukuba)
ISHII Keishi ;r; #!f Z (Dept. Eng. Sci., Kyoto Univ.)
ITOH Yoh {3t Hi ~ (Fac. Sci., Josai Univ.)
KARASHIMA Shosuke ~ Si 1m 1r (Dept. Electr. Eng., Tokyo Univ. of Sci.)
KOIKE Fumihiro IJ~ ~ Jt if (School Med., Kitasato Univ.)
KOIZUMI Tetsuo IJ~ ~ rg-;k (Dept. Phys., Rikkyo Univ.)
KOYAMA Naoto IJ" JlI If[ A (Dept. Eng. Phys., Univ. of Electrocommunications)
MATS UM OTO Atsushi t~~ (Inst. Plasma Phys., Nagoya U niv.)
MATSUO Takashi t~ ~(Dept. Pathology, Tokyo Med. and Dent. Univ.)
MATSUZAWA Michio t~ i* Jm 1:: (Dept. Eng. Phys., Univ. of Electrocommunications)
OHTANI Shunsuke~ ~ 1r (Inst. Plasma Phys., Nagoya Univ.)
ROY Amulya C. (Dept. Phys., Univ. of Kalayani)
SATO Hiroshi 1~ Hi 1~.se. (Dept. Phys., Ochanomizu Univ.)
SATO Kuninori 16: Hi(Inst. Plasma Phys., Nagoya Univ.)
SHIMA Kunihiro lib ~B tf (Inst. Appl. Phys., Univ. of Tsukuba)
SHIMAKURA Noriyuki lib 1t Jft2 Z (General Educ. Dept., Niigata Univ.)
TAWARA Hiroyuki ~ tf Z (Inst. Plasma Phys., Nagoya Univ.)
TOKORO Nobuhiro m 1$ ~ (Res. Lab. Nuc1. Reactors, Tokyo Inst. Tech.)TOSHIMA Nobuyuki F ~~ 1§" $ (Inst. App!. Phys., Univ. of Tsukuba)
TSURUBUCHI Seiji U1J#f ~(Fac. Techno!., Tokyo Univ. Agric. Tech.)

*
*

*

00.

=

(Students)
HINO Kenichi S Jf ~ ~ (Dept. Appl. Phys., Univ. of Tokyo)
KAWAGOSHI Hiroshi )11 j@! r~ (Fac. Eng. Sci., Univ. of Tokyo)

240

SEKIYA Masahiro 00:G 3ft Ij.£ (Dept. Chern., Hokkaido Univ.)
NAKANISHI Kiyotaka t:p 1§ m~ (Dept. Chern., Waseda Univ.)

Metal Physics Laboratory
KOYAMA Akio II, Jli a:g at
SHIOTANI Nobuhiro :!i[:G E Ij.£
(Student)
NAKAMURA Shiho

t:p # ~ 1*

NAGAMINE Kanetada 7k ~ ~ I~YAGI Eiichi j\~-*(School Sci. Eng., Waseda Univ.)

Magnetic Materials Laboratory
ASAI Kichizo ~ it 15 ~SAKAI N obuhiko tlZ it ffi 1fj;.

OKADA Takuya !RiJ S3 .$". lli
SEKIZAWA Hisashi 00 ~ rAJ

Plasma Physics Laboratory
ISHIBE Yukio ;p $ rr at
OKAZAKI Kiyohiko WilllffitmJttl
SAKAMOTO Yuichi tlZ at -ISHII Shigeyuki ;p it ~ rr
OYAMA Hitoshi 7;. Jli ~YANO Katsuki *-!IIt 1m ~*(Student)
KAKINUMA Sadanori;f$m~ fJM. (Fac. Sci. and Eng., Chuo Univ.)

Semiconductors Laboratory(Visitor)
AONO Keiko W!IIt;f-E -T (College of Liberal Arts, Kitasato Univ.)

Solid-State Chemistry Laboratory
KOBAYASHI Masayoshi 11, 3ft ~SASA Yoshihiko ~ k ;a: 1fj;.

**

MAEDA Kuniko M S3 *~ -=f
UDA Masayuki ~ IE J;t z(Visitors)
KUSUY AMA Hiroyuki ;fm Jli Ij.£ Z (Cancer Institute Hospital Tokyo)
YOKODE Yutaka ~ lH
(School of Medicine, Nihon Univ.)
NASR Samir Ahmed Hassan Seif El (Teacher's College for Women, Kuwait)mRadiochemistry Laboratory**

AMBE Fumitoshi$ X fit
ARAT ANI Michi Jfl:G ~ ~ITOH Yoshiko {¥ =!If -=f
NOZAKI Tadashi !l!t J/ffit IE* *AMBE Shizuko$-=f
HAYASHI Shigeki~
IWAMOTO Masako ~ IE -=f
OHKUBO Yoshitaka 7;.tAf**iWi

**

*

m

241

TERAI Yoshiro~ # ~ ~~

(Visitors)
ABE Takao I5iiJ $ :It =;k (Shin-Etsu Handotai Co.)
AIMI Toshihiko f§ Jt ~ tt (NEC Corporation)
FUKUSHIMA Hiroto mSJ'iii A (Japan Chemical Analysis Center)
HASHIMOTO Tetsuo 11 *= rg =;k (Fac. Sci., Niigata Univ.)
IKEDA Kazuko $ IE fn r (NEC Co.)
ITOH Nobuyuki W jj'J f~ z (NEC Co.)KAWABATA Yuji )11 ~ tt iiJ (Res. Reac. Inst., Kyoto Univ.)
KIMURA Toshimasa# ~ iE (Japan Chemical Analysis Center)
KUBOIOsamu /A1*# Jf)( (Komatsu Electronic Metal Co., Ltd.)MASUI Tsumoru m: it fJf (Shin-Etsu Handotai Co.)MINAI Yoshitaka ~ ~ f!::It (Fac. Sci., Univ. of Tokyo)
NAGAI Hisao 7k it MJ1:. (College Hum. and Sci., Nihon Univ.)
NISHIDE Hiroyuki W illz (School Sci. and Eng., Waseda Univ.)OOHIRA Shigeo 7::. -¥:m: ~ (Nikkei Techno Res. Co., Ltd.)SUEHIRO MAKIKO~ !t?c -=t (Tokyo Metropolitan Geriatric Hospital)
TSUCHIDA Eishun ± IE ~ ~ (School Sci. and Eng., Waseda Univ.)
UTSURO Masahiko *$§uttt (Res. Reac. Inst., Kyoto Univ.)
YATSURUGI Yoshifumi )\ ~ ~ Jt (Komatsu Electronic Metals Co., Ltd.)YOKOI Fuji fl it m% (Mental and Muscular Disorders, National Center for Nervous)

*

*

*

(Students)
KUBO Kenya !A 1* ~ 1& (Fac. Sci., Univ. of Tokyo)
OGATA Yoshitaka ~ ~ ~.. (School Sci. and Eng., Waseda Univ.)
YUASA Makoto ~ ~ ~ (School Sci. and Eng., Waseda Univ.)

Radiation Chemistry Laboratory
KIMURA Kazuie*# - *(Visitor)
ITO Yasuo W jj'J ~ ~(Res. Center Nuc1. Sci. and Tech., Univ. of Tokyo)(Students)
AKASU Keiri 7ffi ~ ~t JJI! (Dept. Phys., Chuo Univ.)
AOKI Yasushi 1f
mt (Fac. Eng., Univ. of Tokyo)
AZUMA Toshiyuki~ ff (Fac. Eng., Univ. of Tokyo)
KURIYAMA Tatsuto ~ III ~ A (Dept. Phys., Chuo Univ.)**

Radiobiology Laboratory
EGUCHI Kiyomi iI I=l m~
N AKAN 0 Kazushiro 9=' Jy fn ~YATAGAI Fumio ~IRJtJt=;k

KANEKO Ichiro ~ T - ~~OKADA Shigefumi ~ IE :m: Jt

242(Visitors)
INADA Tetsuo ~ IE t1 Mt (Inst. of Basic Medical Sci., Univ. of Tsukuba)
MAJIMA Hideyuki ~ ~~ ~ ff (Fac. Med., Univ. of Tokyo)
OHNO Tadao
If J~ ~ (Nat. Inst. Radiological Sciences)
OKADA Gensaku ItrrJ IE lJffi f'f (Tokyo-Toritsu-Itabashi-Kango-Senmon-Gakko)*

Safety Control Affairs Office
IGARASHI Kazui 3£+il- J'X:
KATOU Takeo no Hi lEt Mt
MIYAGAWA Makoto 1r )11 ~ i§
T AKI Kenro ~ ~IJ M

KAGAYA Satoru 1Jo~~KURIHARA Osamu ~)Jj{
SAKAMOTO Ichiro #i
US UBA Isao ff. ~ ~m*-Beam Analysis Center
IWAKI Masaya
SAKAIRI Hideo**(Visitor)
YOSHIDA Kazuo:IE i&#i A* Mt

a IE ;til ~ (Toray Ind., Inc.){~KOBAYASHI Takane Ij ... 1*
URAl Teruo rm # • ~

~~

"'*

AUTH"OR INDEXABE Takao I5iiJ tm 1J::k 123
ABE Junya I5iiJ tm ~ ili 170
ADACHI Minoru JE if.. ~ 15
AIMI Toshihiko .:m J! ~ ti 101
AKASU Keiri 7ffi ~ ~t ~ 150
AMBE Fumitoshi
1m X fi;{( 90, 92, 139, 141, 167
AMBE Shizuko
1m f1 -r 90, 92, 121, 139, 141
AMEMIYA Hiroshi'8
205
ANDQ Kozo tJi: Hi ~IJ ~ 69, 71
AOKI Yasushi W
145, 150
AONO Keiko W mf :f-E -r 110
ARATANI Michi )it ~ ~ ~ ij:/01, 103, 130, 134,

*
*

m

*

* '*

ARIMA Akito 1f f.l§ AA A 26
ASAHI Kenichi :M1 1m - 41
ASAI Kichizo ~ tf ~ 92,94,96,167
AWAYA Yohko ~ m'4J. -r 59,71,73,75,77,84,162
AZUMA Toshiyuki Jf( ~ rr 145, 150
BE Suck Hee ~"78, 80, 82, 164, 189, 192
CHENG Xixiang ~ ~:w 45,57
CHIBA Toshiya =f ~ flj 1& 197
CHIBA Yoshiaki =f ~ 9.t f3J:J 4
EG U CHI Kiyomi iI I=l fr!f ~ 148
EL Nasr S.S. 128
FUJIMA Kazumi ifi r~'~ 55, 59
FUJISAWA Takashi ifi rR /filj ~ 172,174,184
FUJITA Jiro ifi IE
t!~ 170,185,187
FUJITA Shin Hi IE ~ 2, 194, 218, 221
FUKAI Katsumaro ~ Jf91 fJif 117
FUKAI Yuh ~1f 104, 106
FUKUDA Mitsunori mIE ~ J/1Jt 30, 32, 152
FUKUDA Tomokazu 1i IE ;J:t: fll 41
FUKUSHIMA Hiroto m~~ ¥~ A 123
FUSE Masaharu ;:{fj:IifE $t fa 164
GONO Yasuyuki ~:II)1# Z 30,32,152
Go.To. Akira ~ ifi ~ 170, 177, 179, 184, 216
GQTQH Eiichiro ~ifi~-t!~ 164
HAMADA Shozo ~ IE 1!f'=' 117
HAMAGAKI Hideki ~:ij[:Jfj.m 10
HAMAJIMA Yasunori ~ 1i!b )tf:f:!J4 12, 37, 143
HARA Masahiro JJj( ¥t 51.. 216
HARA Shunsuke JJj( ~ 1r 49
HARADA Hideo JJj( IE ~ t!~ 22,24

*

1ii:.

-

=

*

*

HASHIMQTQ Masanori 111::<$: IE Jtlj 99
HASHIMOTO. Tetsuo :fi::<$: T:1:k 137
HASHIZUME Akira
JR M 28,96,168
HATANAKA Kichiji j:IIJ q:. tf '$ 181
HATSUKAWA Yuichi 191 )11 Q$ - 12
HAYASHI Shigeki ;f>f: Jt.m ij2,1~h,1~~7130,
HEMMI Masatake ~ J! ~ 1ft iiJ97, 211, 212,214,

m

* **

HIGASHIGUCHI Yasuhiro
1=1
111
HINo. Kenichi ~ mf ~ - 62,64
IGARASHI Kazui 3l.+,m-B<; 221
IGUCHI Kaoru
I=l!iJ 43
IKEDA Kazuko it!! 133 fll -r 101
IKEDA Nobuo ttl! 133 f$ X 41
IKEGAMI Kumio iff!J::n.=.~ 2, 189, 192, 209
IKEGAMI Yuji it!! 1: :tti 'R] 164
IKEZAWA Eiji it!! rR ~4
INADA Tetsuo mi IE T:1 Q$ 148
INAMURA Takashi mi #,!;20,22,24,28,152,

*

=

*

.o:r-

158, 160, 166, 181

INo.UE Toshihiko
1: ~ ti 4
ISHIBE Yukio 15 $ rr Q$ 97
ISHIHARA Masayasu 15 JJj( IE ~ ~51.°i;!"1~~, ~~4
ISHII Shigeyuki :{:i ~97, 205, 207
ISHIKAWA Yoshiharu :{:i) II ~ Il1f 30, 32, 152
ITO. Yasuo W ifi ~ ~ 145
ITO. Yoh W ifi ~ 162
ITO. Nobuyuki Wifi {~ Z 101
ITQH Yoshiko W ~ T 123, 125
IWAKI Masaya ~ IE 1& 7,103,108,109,110
IWAMo.To. Masako ~;;.$: IE -r 121
KAGEYAMA Tadashi ~!1J IE 2
KAKINUMA Sadanori :f$ mj{ ~ 97
KAMBARA Tadashi 1+ JJj( IE 4,73,75,77,78,

* rr

*

*

KAMITSUBo. Hiromichi 1: Pf

80, 82, 84, 185
113, 115, 119,
JH 152, 169, 170,
181, 185209*

KAMIYAMA N orio 1::!1J. Q$
KANEKO. Ichiro ~ -r - t!~ 147, 148
KANG Yuno-Ho ~ ~ 1~ 147
KARASHIMA Shosuke
1i!b H« 1r 57
KASAGI Jirota ~*'$t!~* 22, 24, 152; "158, 160
KASE Masayuki lJO 11 l§\ z ~4,7f9J,\ ~g3 80, 82,
KATAYAMA Toshiko Jl!1J ~ -r 147
KATo. Seigo lJO Ki l\t -B- 155

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KATORI Kenji J& 1& ~41
KATSUMURA Yousuke M1 t-t Jl1r 145
KAWABATA Yuji )1( ~:f;t 'm 132
KAWAGOSHI Hiroshi )/1 ~ 7* 57*

KAWAKAMI Hirokane )111: ~ 15,155
KAYANO Hideo ~!If ~ ~ 111
KIHARA Kiyotaka *}jj( m~ 4
KIKUCHI Shiro ~ ffi! ± ~~ 28
KIM Do-Sung ~ J!! ~ 147
KIMURA Kazuie
1;f - ~ 145, 150
KIMURA Mineo ~;t;f ~ 53
KIMURA Toshimasa *;t;f f!tt IE 123
KOBAYASHI Hirotada IJ"\ 5A,~ 119
KOBAYASHI Masayoshi IJ'\ Jt ~ 128
KOBAYASHI Takane IJ'\
!Ill ~2103, 104, 106,

*

*

**
**
**

KOHARA Shigeo IJ'\ JJj( m~ 2,172, 174
KOHMOTO Susumu fliT
Jf§ 8, 10, 15, 69, 71*

2, 12, 37, 78, 80, 82, 99,
KOHNO Isao f1iT!l!f !h 101, 113, 115, 119, 130,
134, 13~ 143, 152, 209,
218
KOIZUMI Tetsuo IJ"\ ~ rg ~ 162

KONNO Chikara 4- If tJ 41,155
KONNO Satoshi ~ If tr 156
KOSAKO Toshiso IJ'\~ilfittE 194
KOYAMA Akio 11'\ ~ lIB $ 86, 88**

KUBO M. Kenya ~ ~ ~ 121
KUBO Toshiyuki ~ fit $ 4, 8, 15
KUBOI Osamu R*# 1& 99, 130, 134
KUBONO Shigeru ~*!l!f m 155
KUDO Hisaaki I jfj ~ lIB 15,35,37,166
KUMAGAI Hidekazu

1m ~ ~ fu*m71, 73, 75, 77,
78,80,82,84,
162, 164KUMAHORA Hiroki 1m 1fpJ
28
KUMATA Yukio 1m fE ~ 1: 174
KURIYAMA Tatsuto ~ III ft AlSOKUSUYAMA Hiroyuki 1m III 5A Z. 128
LIU Yaoyang 1'1 Jti ~ 45, 57
LIU Zhijing 1'1 Z ~ 45, 57* **MOTOBAYASHI Toru
~ 39
MOTONAGA Shoshichi :Ji; 7k lIB -t 119,170
MURAKAMI Takeshi ;t;f 1: ~ i~b 24,152,158,
NAGAI Hisao 7k # ~ 1: 99, 101, 130, 134, 137
NAGAI Yasuki 7k # ~39
NAGAKAWA Johsei 7k )11 ~ IE 115
NAKAHARA Hiromichi t:p}jj( 5A it 12,37, 143m=

NAKAJIMA Shunji t:p Ii ~189, 192
NAKAMURA Shiho t:p;t;f;!; * 104, 106
NAKANISHI Kiyotaka t:p W -m ~ 43
NAKANISHI Noriyoshi t:p W
179,194
NAKANO Kazushiro t:p!l!f fll ~ 148
NAMBA Susumu ~ ~ :l1§ 110
NISHIDA Masami W fE lit ~ 75
NISHIDE Hiroyuki W ill Z 121
NODA Takashi If /II ~ 209
NOJIRI Yoichi !l!f mfF - 41
NOMURA Toru If;t;f 1f 15, 35, 69, 152, 166

{(l2.

*

NORIKI Shinichiro ~Ibt~~-~~ 126
NORO Takeshi !l!f g JEt 'm 67
NOZAKI Tadashi !l!f ~ IE 99, 101, 121, 123, 125,
IJ '\ -*IE Jf.t,>r.~

ODERA Masatoshi

130,132,134,137,168
4,203, 207,211,212,
214,216

OGATA Yoshitaka ~ ~ . . . 121
OGIWARA Kiyoshi ~}jj(
2,172,174
OHKUBO Yoshitaka "*~*_fWj 123
OHNO Kimio "*!l!f ~ ~ 67
OHSAKI Akihiko "* ~ ~ ~ 43
OHSHIMA Masumi "* Ii ~ m 28
OHSUMI Hideaki "* lIM ~ ~ 10, 39
OIKAWA Yoshifumi ~ )11
172,189,192
OKADA Shigefumi ItrrJ fE
X 147
OKADA Takuya IMJ fE lii -if! 90, 92,94, 139, 141

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MA Quaching ~ T
45,57
MAEDA Kuniko M fE ~ T 126, 128
MAEDA Masaru M fE 5 126
MAGARA Masaaki rFl' Wi IE WI 12, 35, 37, 143
MASUDA Kimiaki mfE ~ WI 156**

MASUI Tsumoru# fJf 123
MATSUO Takashi t~ ~ ~ 84
MINAI Yoshitaka ~ ~ {3!:Jt 121
MINAMISONO Tadanori miii ,~;tlj

MINEHARA Eisuke ill JJj( ~ 1r 28
MINOH Arimichi rt Jib 1:E J!! 97
MISAWA Yutaka :=: iR • 125
MITA Takeshi :=: fE fi:t 170
MIYAZAWAYoshitoshi rg iR {3! fit 4, 197
MORITA Kosuke ~ fE r~ 1r 15, 155, 166*

OKAMOTO Sunao ItitJ;fr 132
OKAZAKI Kiyohiko ltitJ",mJtil 97
OLSON R. E. 53
OOHIRA Shigeo "* 1f m~ 103
OYAMA Hitoshi
III ~ 97
ROY A. C. 47, 51
SAITO Hajime 1f jfj •170
SAITO Takaichi 1f jfj ~ 125"*

41

SAKAI Nobuhiko ~ jf m~ 96,167
SAKAIRI Hideo ~ A ~ it 6,103
SAKAMOTO Ichiro ~~~ 218, 221
SAKAMOTO Yuichi ~ at - 97,205,207
SASA Yoshihiko f:£ k~ 86,88,126,128
SASAKI Fukashi f:£ k *~1=iJ 1.1: 67
SATO Hiroshi ~ jJj 1~ 51! 53
SATO Kenichi f~ jJj • 18
SATO Kuninori f~ jJj 00. 71
SAWAI Tomotsugu tR tt: 1R tX 117
SEKIYA Masahiro ~ ~ ~ 5.h 67
SEKIZAWA Hisashi ~ rR ~ 90,92,94,141
SHIBATA Hiromi ~ /±f m~ 73,75,77,78,80,82,

TAWARA Hiroyuki #( ft Z 78, 80, 82
TENDOW Yoshihiko ~ J1t =:Ii ~ 168
TOHYAMA Mitsuru ~ I-D iiMJ 14
TOKORO Nobuhiro FJT f$
84
TONUMA Tadao F
JE it 71, 77, 78, 80, 82
TOSHIMA Nobuyuki F ~~ m$ 62
TSUCHIDA Eishun ± /±f ~ ~ 121
TSURUBUCHI Seiji .. rJllf ~71
UDA Masayuki ~ IE r.t- Z 86,88,126,128
URAl Teruo iii tt: *,;k 6
UTSURO Masahiko ~$gat~ 132
WADA Takeshi fn /±f it 170,185
WATANABE Kenji ~ ill .Df tX 104,106

SHIKATA Takashi Il9 j} Ili 51! 113,115,194
SHIMA Kunihiro lib :m ft 75
SHIMAMURA Isao lib #~ 47, 62, 64
SHIMIZU Kazuo
fn ~ 185
SHIMODA Tadashi ""f /±f JE 39, 41
SHIMOURA Susumu ""f tm :$ 41
SHIRAISHI Haruki s;r; *;f1tt 113,115
SHIRAISHI Kensuke s;r; .Df 1r 117
SUEHIRO Makiko~ !I?c T
121
SUEKI Keisukefl§ 1r 12, 15, 35, 37, 143, 166
SUEMATSU Tatsuya
t~ if ili 119
SUGAWARA Masahiko 1f)Jj{ ~ ~ 30,32,152
SUGIMOTO Kenzo ~ {j! ~ 10
SUZUKI Yoshimitsu ~ E ~ 111
TABATA Yoneho /±f;:m ~ 145
TACHIBANAKI Hiroshi ;fiJt 22,24
TAKAHASHI Tan iWi;ff,fj JL 147,148,156
TAKEBE Hideki ftt $ ~;f1tt 2,170,218
TAKESHITA Isao 11" r ~;k 170,184,199
TANABE Tetsumi IE ill rfft ~ 10
TANAKA Masahiko fE If It ~ 155

WATANABE Tsutomu**-=

84, 162

m*

*
**

*
*
*
*

*

*

m

=

fJ

~ $

w.

43,45, 51, 55,
57,59,62,64,
67

WATANABE Tokuji rli ill ta 209
YAGI Eiichi /\6,104,106,111,117
YAMAGUCHI Kazuya JlI t=l fn ili 181
YAMAMOTO N orikazu I-D fj&. fn 113
YAMAJI Shuhei I-D Jm f~ ~ 14
YANO Katsuki
Jy M1. 97
YANO Yasushige
Jy ~:m 177,179,181

* *-

*

*
*

4, 99, 101, 103,

YANOKURA Minoru *!llfit ~ 119,130, 134,
137, 201, 205,
207, 221YATAGAI Fumio ~fEjt>c;k 147
YATSUHASHI Motoharu i\;ff,fj jG fr3 119
YATSURUGI Yoshifumi I\, ~IJ E X 99,130,134
YOKODE Yutaka t1t tH m 128
YOKOI Fuji t1t tt: & W. 121
YOKOYAMA Ichiro t1t I-D - ~~ 185,199
YOSHIDA Kazuo E /±f fn;k 22, 24, 109
YOSHIDA Nobuaki E /±f E::$: 26
YUASA Makoto i'9i ~ • 121
YUNOKI Akira ffII

*

~

147

lIKEN Accelerator Progress Report
JIUt~iijf~fiJT:l.Jn~ft!F~flli5-

F/l Aillj

56 ff
56ffl'-~18* (1984)

IIBfll60 ~ (1985) 6 fj 2513
IIBfll60 ~ (1985) 6 fj 30 13:00 f~ $. iJf 5i: BY
~~;f

'if

;=351-01

Gb

fi~

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j:ilt::E.!Ji';fll~m~iR 2 ii 1 %flms (0484) 6 2-1 1 1 1~"~~$.iJf5i:m~ • • ~~~A~~ fF

M~~A $. ~ ~ flj ff -e ~ -7 ;= 113 J10i(iltieJRI2S]If'!:E 2 T ~ 4 ii16%

F/l~m

iJf 5i:;=~2~ro _ •~~~_::E.!Ji'; • • m.*~7T~Uii8%~1iffi 5,OOOfq

理化学研究所
埼玉県

和光市

広沢