RIKEN
Accelerator
Progress Report
vol.

15

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

RIKEN Accelerator Progress Report
January-December

J~ 1t ~~ff ~ fifT

the Institute 01 Physical and Chemical Research
Wako-shi, Saitoma, 3SJ JAPANEditors
F. AmbeY. GonoA. Hashizume

T. Inamura

H. Kamitsubo

N. Shiotani

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 fromthe publisher.

PREFACE

This is the fifteenth issue of the progress reports on research activities at the IPCR Cyclotron.
The first beam from the cyclotron was obtained in October in 1966 and the collaborative researches
started in 1967. Many important researches on nuclear physics, atomic and solid state physics,
nuclear and radiation chemistry and radiation biology have been carried out in these fifteen years.
The progress reports on these activities have been issued annually since 1967.
Need for a new accelerator increased in recent years at IPCR to develop researches using thecyclotron , and construction of a new heavy-ion linac started in 1974. It was finished in 1980 andbeam acceleration tests are being carried out by now. At the same time the collaborative researches
using the linac started and many experimental facilities and devices have been installed at the
linac. Research works using the linac are in progress.
Now at IPCR the research activities using accelerators are developing in the new and wider
area in the fields of science and technology. Under these circumstances we decided to issue theprogress report of the IPCR Cyclotron in a new format. It contains not only the results obtainedat the 160 cm cyclotron but also those at the linac and other small accelerators. This new format
is to reflect the growing activities in the research fields of basic and applied nuclear science at our
Institute. At the same time the name of RIKEN will be used instead of IPCR. RIKEN is a
traditional abbreviation of the Institute of Physical and Chemical Research.
This volume summarized studies on nuclear physics, atomic collisions, solid state physics andmaterial engineering, radio chemistry, radiation biology and so on in a period from January to
December in 1981. There are also many reports on the developments in the accelerator technology
and design study of the new separated sector cyclotron which is now under construction as thepost accelerator for the linac.
I would like to acknowledge the effort of Dr. K. Mori to prepare the new format of the
RIKEN Accelerator Progress Report.

Hiromichi Kamitsubo
Editor

CONTENTS
Page
I.

INTRODUCTIONII.

OPERATION OF ACCELERATORS

III.
1.

1.

Machine Operation2.

Operation of Heavy Ion Linear Accelerator

3.

TANDETRON -Operation

11......................... .

14
16

RESEARCH ACTIVITIES
Nuclear Physics
1.

Bare Potential DWBA for (d, p) Reactions

17

2.

Mass Diffusion Coefficients in the Adiabatic Approximation

20

3.

Non Perturbation Effect on the Nucleon Transfer
Amplitudes in Close Contact Heavy-Ion Collisions

23

4.

Full Finite-Range CCBA Analysis of the 22Ne (p, t) 2oNe Reaction

26

5.

Extended Brink Model and Its Derivation from Distorted
Wave Born Approximation .......................................

28

Angular Distribution of Reaction Products in Preequilibrium
Process .......................................................

30

Strongly Damped Components in the Reaction of 20Ne + 50Cr
and 20N e + 54 Cr Systems ........................................ .

33

Incident Energy Dependence of Heavy-Residue Products
in 14N + 62Ni ................................................. .

37

Light-Particle Emissions in the 93Nb + 14N Reactionin the Region of "'7 to '" 15 Me V / A ............................... .

40

Alpha Particle vs. Ejectile Correlations in the
93Nb + 14N Reaction at 208 MeV ................................ .

43

Projectile Dependence of Fast Light-Particle Emission
in Heavy- Ion Reaction

45

Polarization of Continuous Protons Emitted at 40°
in the 93Nb + 14N Reaction ..................................... .

48

6.

7.

8.

9.

10.

11.

12.

Page
13.

Light-Particle Emission Following 7 Li-Induced Reactions

50

14.

Influence of Chemical Environment on Outer-Shell Internal
Conversion in 119Sn ... . ....................................... .

51

15.

Highly Neutron Deficient Nuclei 157Yb ............. . ............... .

54

16.

Calculation of Gamma-Ray Multiplicity Moments Associatedwith Massive-Transfer Reactions ...................................

57

Angular-Momentum Transfer and Alignment Following
Preequilibrium ~-Particle Emission in Heavy-Ion Reactions

60

18.

Search for ~-Decay from High Spin Yrast Region

61

19.

In-Beam ')'-Ray Spectroscopy of 216Ra

64

17.

2.

Atomic and Solid-State Physics
1.

A Broad Range Crystal Spectrometer

66

2.

Angular Distribution of X-Rays Following Multiple
Inner Shell Ionization ........................................... .

69

3.

Ionization of Gases by Ion Bombardment ........................... .

70

4.

Target Gas Pressure Dependence of X-Rays from 110 MeV Ne 9 + Ions .....

71

5.

Chemical Effects on F, Al and Si K~, and Cu L~ Satellite
Spectra Produced by 2.4 MeV He++ ..................... . ......... .

73

Chemical Effect on 0 K~ Satellite Spectra Inducedby 2.4 MeV He++ Ions .......................................... .

75

7.

Preliminary Experiments for PIXE

77

8.

Backscattering Spectra from Silicides

9.

High Resolution Electron Spectrometer......... . .................. .

81

10.

Parallel Plate Electrostatic Spectrograph Using MCP and PSD ........... .

83

11.

Beam-Foil Spectroscopy

85

12.

Optical Detection of Atomic and Nuclear Spin Polarization
Produced by Beam-Foil Interaction

86

Lattice Location of Sn Atoms Implanted into Al Crystals
as Investigated by Means of Channeling Method ..................... .

87

6.

13.

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

79

Page
14.

Secondary Electron Emission from Metal Targets
under Heavy-Ion Bombardment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

88

Distributions of the Hyperfine Magnetic Field at
119Sn ( +- 119 Sb) on the Surfaces of ~-Fe203 ......................... .

91

16.

Angular Correlation Measurements on Nb-Mo System

94

17.

Creep Properties in Helium-injected SUS 316 andI'" -Precipitation Strengthened Alloy ............................... .

95

18.

Channeling in Argon-Implanted Diamond ........................... .

98

19.

Ion Beam Mixing of the Aluminum Film-Iron
Substrate Interface ............................................ .

100

15.

3.

Radiochemistry and Nuclear Chemistry1.

Charged Particle Activation Analysis of Semiconductor Materials

103

2.

Charged Particle Activation Analysis for Surface Oxygenon Silicon and Aluminum ............................. "...........

105

Heat Treatment Behaviour of Oxygen in Silicon as Measured
by Charged Particle Activation Analysis ............................ .

107

4.

Effect of Carbon Precipitation on Gold Diffusion in Silicon

110

5.

Separation and Purification of Carrier-Free 119Sb from
119mTe Produced by the Sn(~, xn) Reaction ....................... .

112

Adsorption Kinetics of Carrier-Free 119Sb(V) onto~-Fe2 0
3 Surfaces ............................................. .

114

3.

6.

4.

5.

Radiation Chemistry and Radiation Biology
1.

Inactivation of B. Subtilis Spores by Heavy Ions

116

2.

Relative Biological Effectiveness of Nitrogen Ions on
Inactivation of Cultured Mammalian Cells .......................... .

117

Instrumentation
1.

Gamma-Ray Circular Polarimeter2.

Neutron Detection in In-Beam Spectroscopy

119........................ .

121

Page

3.
IV.

Data Processing System at RILAC

123

ACCELERATOR DEVELOPMENT
1.

New Gas-Feed System and Acceleration Test of
Heavy Ions with Gas Mixing ......................................

125

2.

Beam Acceleration Test at RILAC................................ .

128

3.

Performance of Light Link System for Control ofInstruments on High Voltage Terminal ..............................

131

4.

Metal Ion Source ... . . ............ ..... ...... ........ . ......... .

133

5.

Construction of ECR Ion Source .................................. .

136

6.

Simplified Control Circuit for RILAC RF System.......... .... ...... .

137

7.

Design of Compact Quadrupole Magnet............................ .

139

8.

Simple Pepper-Pot Device for Beam Diagnostics

140

9.

Performance of Digital Emittance Measuring Device

141

10.

Single Arm Motor-Driven Slit System ............... .... ......... .. .

144

11.

Simple Low-Cost Profile Monitor

146

12.

Beam Attenuation by Slit with V-Slots

13.

Status of the RIKEN Separated Sector Cyclotron Project14.

Some Results Obtained from Orbit Calculations

152

15.

Formulation of Beam Centering Equation in a
Separated Sector Cyclotron ..................................... .

155

Beam Centering and Related Problems in a Separated
Sector Cyclotron ........... ...... . ............................ .

157

17.

Design of Injection and Extraction Harmonic Coils for the RIKEN SSC ....

159

18.

The Sector Magnet for the RIKEN SSC

162

19.

Structural Analysis of Sector Magnet by Finite Element Method

166

20.

Model Test of the Trim Coil for the SSC ........................... .

169

16.

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

148. .. . ... ....... .

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

149

Page

V.

21.

Design of the Trim Coils for the RIKEN SSC ........................ .

173

22.

Automatic Measuring System of Magnetic Field Distribution

177

23 .

Beam Transport System for the RIKEN SSC (II)Injecting Transfer Line .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

179

24.

Beam Extraction System for the RIKEN SSC (I) ..................... .

183

25.

Model Study of Magnetic Inflection Channel for the SSC

185

26.

Calculation of RF Electromagnetic Field by Finite
Element Method ................. .. ... ...... ....... ...... . . . .. .

190

27.

Model Study of RF Resonator for the RIKEN SSC ................... .

193

28.

New Method to Vary Resonant Frequency of Resonator for SSC ........ .

196

29.

Vacuum System of the sse (I) ... . .... ... ..... ...... ... ... .. .. .. . .

198

30.

Vacuum System of the SSC (II)

200

31.

The sse Beam Handling System

203

32.

Status of Radiation Shielding for the RIKEN SSC Facility .............. .

206

33.

Status of the Prototype Baby Cyclotron

209

RADIATION MONITORING
1.

Routine Monitoring ............................................ .

212

2.

Leakage-Radiation Measurement at the Underground Passage........... .

214

3.

Examination of Shielding Performance of Doors in the Linac Building . ....

216

VI.

LIST OF PUBLICATIONSVII.

LIST OF OUTSIDE USERS AND THEIR THEMESVIII.

LIST OF SEMINARS

228

IX.

LIST OF PERSONNEL230

AUTHOR INDEX

218........................

226

I.

INTRODUCTION

H. Kamitsubo

Nuclear science is one of principal subjects of the research activities at the Institute of Physicaland Chemical Research (Riken). Collaborative researches on physical, chemical, biological andother problems using accelerators started at Riken in 1967, when the 160 cm heavy-ion cyclotron
was completed and brought into stationary operation.

In the early time, most of the beam time

was devoted to the studies of nuclear physics and machine development. However shares of theresearch fields other than nuclear physics. in the beam time have gradually increased and many
significant results have been obtained in these studies.
Systematic studies of heavy-ion reactions and nuclear structures of heavy nuclei are thetypical examples of works in the field of nuclear physics. Charged particle activation analysis
of carbon and oxygen impurities in the high purity semiconductors, production of radio-isotopes
for medical uses and synthesis of physiological compounds labelled with them, radio lysis studies
of inorganic and organic compounds by heavy ions and studies of radiation effects on biologicalmaterials at different LETs are also examples of pioneering works in Japan using accelerators in
the fields of chemistry and biology. Simulation studies of materials for FBR and thermonuclear
fusion reactors by alpha-particle irradiation and those of semiconductor devices for space satellites
are the important applications of accelerators and have been promoted at the 160 cm cyclotron.
It has been recognized that energetic heavy ions play an important role to develop new areas
in various research fields and there have been increasing demands for accelerators of high quality.
In 1974 there started the construction of a heavy-ion linac (Rilac). It was completed in 1979 andis now in test operation. Rilac is designed to be an injector for a big separated sector cyclotron(SSC) with k = 540. The SSC project was granted in 1980 and two sector magnets will be completed
in 1982. The SSC is one of the biggest heavy-ion cyclotrons now under construction in the world.
On the other hand a 200 kV ion implanter was installed in 1975 to develop modification andimprovement of physical, chemical and mechanical properties of near-surface region of metals,
semiconductors and insulators. In addition to this machine a tandem Van de Graaf accelerator(Tandetron) of 1 MV was also installed in 1979 for the studies of characterization of solid materials
and particle-induced X-ray spectroscopy (PIXE).
Collaborative and interdisciplinary researches by use of the cyclotron, Rilac, the ion implanter
and Tandetron are now in progress. Heavy ion reactions were extensively studied in 1981 as in
the preceding years.

Search for short-lived ~-decays from high spin yrast states was newly started.

Studies of atomic collisions were pursued in 1981 using the cyclotron, Rilac and Tandetron. A
high resolution electron spectrometer and other measuring devices have been installed at the Rilac.
Collaboration with National Research Institute for Metals on the development of metals having
low swelling characteristic was continued in this period.

Charged particle activation analysis wasapplied to study the behavior of impurity oxygen on the surfaces of high purity silicon andaluminum.

Radiation-biological studies were continued for cultured cells.

Brief descriptions of

the cyclotron, Rilac, Tandetron and the ion implanter are given in the following.

2

160 cm Cyclotron

I. Kohno

The 160 cm cyclotron is of a weak focusing type and its project was authorized in 1962.
The first beam was accelerated and extracted in October, 1966, and research program started in
February 1967. Since that time the cyclotron has been operated for about 42000 h, and has beenused for the studies in many fields of research , such as nuclear physics, atomic physics, solid statephysics , nuclear chemistry, radiation chemistry , radiation biology, production of radio isotopes for
medical use and nuclear fuel study. In Tables 1 and 2 the cyclotron characteristics, and kindsof ions being accelerated at present are shown , respectively.
Table 1.

Cyclotron characteristics.

Acceleration system
Number of dees
Dee width
Beam apertureRadio frequency
Tuned byGain max.
Dee-gnd. max.
RF power input max.
MagnetType of Magnet

2
180 deg.
5 cm
6 to 12.5 MHz
movable short plus movable panels
400 kV /turn
100 kV150 kW

Circular triming coils

weak focusing type
162 cm73 cm
26 cm
2.0 Wb/m 2
4 pairs

Weights Fe (Cu)Magnet excitation

310 (20) tons
6 X 10 5 amp-turns

Power max.

400 kW

Pole tip dia.
Extraction radiusGap between pole tips
Field at max. excitation

Ion source
For light ions (H, He)
For heavy ions (Gas)
For heavy ions (Solid)

Livingston type
Electron bombarded hot cathode PIG type
Same with sputtering electrode3

Table 2.

Particles, energy ranges and particle yields.

Particle

Energy (Me V)

P

5 - 1730

Extracted beam current (IlA)d

8 - 2630

3He++

12 - 50

30

4He++

16 - 5230

6Li 2+

25 - 480.2

7 Li2+

29 - 48

2.0

7Li 3+

29 - 75

0.05

9 Be3+

45

0.8

lOB3+

60

0.3

11 B3+

66

1.3

12C4+

55

14N4+

65

14N5+

100
60 - 125

3.0
1.0 (3.0)a)

16 0 5+65 - 125

1.0 (3.0)a)

19 F5+

80 - 1300.3

19 F6+

80 - 150

2oNe6+

82 - 160

0.1
0.3 a)

100

3.0a) Pulsed operation.

RILAC, a Variable Frequency Heavy-Ion Linac

M.OderaThe recently completed RILAC has been designed to accelerate ions of almost all heavy
elements in the periodic table.
the aim.1)

It incorporates a novel variable frequency linac scheme to realize

The scheme also permits a good beam transfer efficiency to the next post-stripper

accelerator which is the separated sector cyclotron, by use of the same accelerating rf frequency forboth machines.
The reason why the linac was chosen for acceleration of the heavy-ions stems fromconsideration of the state of art of the ion source technology, the loss of ions by charge exchange
collisions during acceleration and the inherent large magnetic rigidity of the fast heavy ions.

Alarge open-air high voltage terminal is used as an external injector to the linac and can house any

4ion source of rather complicated and power consuming characteristics. 2 )Short accelerating pathand the structure which allows to attain high vacuum along the path will minimize charge changing
effect by collision of accelerated particles with the residual gas.

The straight line of acceleration

permits to neglect the large magnetic rigidity effect except for the focusing magnets contained in
the accelerating electrodes to counteract the inherent defocusing effect of acceleration in the linac.
We have developed the compact and high gradient quadrupole magnets to be installed in the drift
tubes (accelerating electrodes) to solve this problem. 3 )In addition, the variable frequency scheme

is effective to relax the requirements for focusing strength of the quadrupole magnets by use of thelower frequencies for the heavier projectiles.
The variable frequency scheme involves several technical difficulties which hitherto havedelayed realization of this type.

The largest problems are its cavity structure, rf source andoperation by remote control, especially of the high power amplifiers in the variable frequency
mode.

Firstly, we have developed a suitable structure after studies by the models andcalculations. 4 )Then, a proty-type amplifier chain was fabricated and made to work in January

1979 , though frequency range was between 17 and 35 MHz and was much lower than the final
goal of 45 MHz maximum. S ) The first beam using the proto-type amplifier was obtained in thatyear.

Incorporating some modifications found necessary by the operation of the first amplifier,other five amplifiers were ordered and fabricated in a factory including modification of the firstone itself.

Acceleration of beams by synchronizing a few amplifiers was made in March and thebeam by the semi-automatic control of the whole six amplifiers was obtained in October 1981 at
20 MHz.

In the semi-automatic control mode, starting up procedures of cavity excitation such as

crossing of the multipactoring region, search of the optimum power level and choice of the relative
phase difference between cavities are made mannually.

After a suitable operating condition isfound, the stabilizing circuit of the accelerating voltage and phase is switched in and the automatic
mode operation begins.

In future, most of the starting up procedures will also become automaticeither.
In Table 1 some examples of energy of ions obtainable are shown.
The energy of ions can be varied in three ways.

By adjusting frequency, it can be changed

continuously. Also, decrease of energy by discrete steps is possible by simply switching off a few
sections of the cavity chain.

Lastly, energy can be changed continuously but in narrow range by

adjusting the relative phase of rf of the last one or two cavities.

Probably the third is the mostconvenient way and takes least time.
There is a relationship among frequency F, charge to mass ratio q/ A and total effective
acceleration voltage V expressed as (A/q)F 2 IV = const.

In the initial design, this constant is 500

when the total voltage gain is 16 MV F being given in MHz, A in atomic mass unit and q inelectronic charge unit.
V Me V.

Ions of charge states within this limit can be accelerated up to q times

If voltage holding capacity of the cavities is improved in the future, V can be increased

and the energy of the large-mass ions may be increased by the same ratio.

In that case, thefrequency larger by a factor of the square root of the ratio of the energy must be used.
there is an upper limit for the frequency, this does not apply to light elements for which
maximum accelerating frequency is already used.

Since

5

Table 1.

Examples of ions and their energies.
Maximum freq.

Maximum energy

Ion

ChargeNe- 204

40.3 MHz

65 MeVAr- 40

4

28.5

65

Ar- 40

7

37.6

114

Kr- 84

8

27.8

130

Xe-132

9

23.5

146

References
1)

M.Odera: IPCR Cyclotron Progr. Rep.,.i, 24 (1970); M. Odera and T. Tonuma: Proc.6th
Intern. Cyclotron Conf., (Eds. Burgerjon and A. Strathdee), Vancouver (1972); AlP Conf.
Proc. No.9, p. 283; T. Tonuma, F. Yoshida and M. Odera: IEEE NS-23, No.2, 1031 (1976).

2)

3)

M. Hemmi and M. Odera: IPCR Cyclotron Progr. Rept.,2, III (1975); M. Odera: Proc.
1976, Proton Linear Accelerator Conf., (Ed. S. O. Schriber), Chalk River, AECL-5677, 62(1976).
M. Odera and M. Hemmi: IPCR Cyc1otorn Progr. Rep. , Q, 21 (1972); Y. Miyazawa, T. Inoue,and M. Odera: ibid.,j0 113 (1975); I. Takeshita, I. Yokoyama, and M. Odera: ibid., p. 118;
M. Hemmi and M. Odera: ibid.,.§., 155 (1974); T. Inoue and M. Odera: ibid., p. 159;
Y. Miyazawa and M. Odera: ibid., 10, 127 (1976); I. Takeshita and M. Odera: ibid., p. 129;
Y. Miyazawa, T. Inoue, M. Hemmi, Y. Chiba, F. Yoshida, and M. Odera: ibid., p. 130; I.
Takeshita and M. Odera: ibid., p. 132; I. Takeshita, I. Yokoyama, and M. Odera: ibid.,
p. 133; I. Yokoyama, I. Takeshita, and M. Odera: ibid., p. 135; I. Yokoyama: ibid., p. 138;
I. Takeshita, I. Yokoyama, T. Kambara, and M. Odera: ibid., p. 140; M. Odera: Proc.

1976 Proton Linear Accelerator Conf. (1976).
4)

M.Odera: IPCR Cyclotron Progr. Rep.,~ 16 (1972); M. Odera, T. Tonuma, M. Hemmi,
and Y. Chiba: ibid., L 143 (1973); M. Odera, Y. Chiba, Y. Miyazawa, and M. Hemmi: ibid .,~ 138 (1974); M. Odera and Y. Chiba:

ibid., p.139; Y. Chiba and M. Odera: ibid., p. 142;

M. Odera: ibid., p. 144; Y. Miyazawa, M. Hemmi, and M. Odera: ibid., p. 146; M. Odera,
Y. Chiba, M. Hemmi, T. Inoue, y.. Miyazawa, T. Tonuma, and F. Yoshida: ibid., p. 148;
Y. Miyazawa and M. Odera: ibid., p. 150; Y. Miyazawa and M. Odera: ibid., p. 151; S.
Takeda: ibid., p. 157; Y. Chiba: ibid.,!Q., 144 (1976); M. Odera: Proc. 1976 Proton Linear
5)

Accelerator Conf. (1976).
Y. Chiba: IPCR Cyclotron Progr. Rep., 11 141 (1979); Y. Chiba: ibid., p. 143; M. Kase,
M. Yanokura, Y. Chiba, and T. Tonuma: ibid., ~ 117 (1980); Y. Chiba: ibid., p. 120;
T. Kubo and Y. Chiba: ibid., p. 123; M. Odera, Y. Chiba, and T. Kambara: Proc. 1979
Linear Accelerator Conf., (Ed. R. L. Witkover), Montauk, BNL-51134, p. 28 (1979).

6

Tandetron

H. Sakairi

Tandetron is , as her name suggests, a tandem type ion accelerator, a commercial productof General Ionex Corporation (Glx) in U.S.A. The first machine was supplied to the Hew lettPackard , California, in 1979 and the second machine was introduced into Riken in Feb. 1980
and licenced to be operated by the Science and Technology Agency in Feb. 1981.

Operation fortest and scientific experiments sta rted in March.
The tandem type accelerator was preferred because the ion source is held at ea rth potential.
The scheme widens the range of selection of the type of ion sources, which is important in thesense that it can responds to the increasing demand for heavy ions in the field of material science.
The Riken Tandetron is equipped with two ion sources, a duoplasmatron and a sputter
source.

The former has been used mainly for helium ion production.

Positive ions fromduoplasmatron are changed to negative ions by passing through a lithium vapour canal.

In thelatter source, cesium ions are used as primary ions for sputtering to produce negative secondary
ions from a solid target.
High voltage for acceleration is generated by a Cockcroft-Walton type circuit.
varied between 0 .35 MV and I MV.

It can be

The accelerated negative ions are changed to positiv e ionsat the coupler of the tandem , which is a nitrogen gas canal.

The ion beam is focused, after

final acceleration, by a doublet of electrostatic quadrupole and infl ected by + 15 ° or +30° with ananalyzing magnet, the ME valu e of which is 136 for the IS ° port.
Specifications of beams are
H+

He 2 +

J1A at 2.0 MeV,

Si 3 +

0.1 J1A at 3.0 MeV,
0.5 J1A at 4.0 MeV,
5 J1A at 4.0 MeV,

Au 3 +

J1A at 4.0 MeV.

N 3+

Main experimental faciliti es are a Rutherford back scattering (RBS ) spectrometer and an ion
indu ced X-ray spectrometer.

In the scattering chamber for RBS , a three axis goniometer was

installed to make the channeling RBS measurement possible.

Scattered ions are energy analyzed

by a silicon detecter and Elcor-Northern TN-4000 MCA system.

On the downstream of thatchamber, another small chamber was placed which was designed to mak e a quick exchange of asample holder easy, in the RBS , measurement without channeling effects.
High resolution X-ray spectrometer with double crystals was constructed to observe chemical
effect on outer shell electrons, in the peak structure of ion induced X-ray spectra.

Crystals used

are EDDT, RAP, LSD, Ge, and ADP , and the detecter is a proportional counter of gas flow type.
The energy range of measurement covers 0.18 to 3 keV , and the resolving power is, for example,
0.8 and 2.5 eY for Al KO' and S KO' respectively , which is almost equal to the energy band width .
Current subjects of research are depth profiling of implanted ions in solid materials by RBS
spectroscopy (performed by Friction and Lubrication Lab. , Deformation Processing Lab. ,Semiconductors Lab., Inorganic Chemistry Lab., and Beam Analysis Center), identification of lattice

7

location of implanted ions in crystalline solids by channeling RBS spectroscopy (by Metal Physics
Lab. and Beam Analysis Center) and study of chemical effect of outer shell electrons in chemicalcompounds by ion induced X-ray spectroscopy (by Solid-state Chemistry Lab .).

Fig. 1.

Tandetron.

Fig. 2.

The scattering chamber for thechanneling RBSS (left) and the double
crystal X-ray spectrometer (right).

RIKEN 200 kY Low Current Implanter

M. IwakiSince the mid-1960s, ion implantation has been used extensively by the semiconductor device
manufacturing industry as the method of introducing controlled amounts of dopants into the surface
layer of semiconductors.

The principal advantages for the application include improved

controllability and reproducibility for silicon device fabrication, as compared with thermal diffusion .
The remarkable results of research in ion implantation into semiconductors have made an advancein ion implantation equipments (ion implanters).

In general, an ion implanter consists of an ion source, an ion acceleration system, a mass
analyzer, a target chamber and a vacuum pumping system.

This association can be considered as

the particle accelerator combined with the isotope separator used for studies of nuclear physics,
high energy physics, etc.. Therefore , an ion implanter, so called, is a kind of ion accelerator whose

8

acceleration voltage is defined as several tens to a few hundred kilovolts.
The ion implanter constructed in our institute at 1975 , was originally planned and built for
impurity doping in semiconductors by Central Research Laboratory, Hitachi Ltd. in 1970.

Many

parts of the present ion implanter were altered for performing modification of the near-surface
region of various materials such as metals.

A schematic drawing of the present apparatus is shownin Fig. 1. Ions extracted at 20 - 30 kV are focussed by a cylindrical einzel lens, accelerated at
30 - 170 kV, mass-separated by the magnet, swept by the X-Y scanner, and bombard the substrate.
The full 200 kV acceleration can be used up to about mass 90.
characteristics of the implanter are presented in Table 1.

The types of components and

CD I on source@ Acce lera tor® Sca nner or def lector@ Gate val ue with a t arget chambe r ( C)

® Deflector® Slit(j) Bea m mo ni tor® Mag net
® Slit@@ Beam monitor@ Scanner@@ Gate valve@ Shutt er@ Faraday c up
@ Target c hambe r ( A)
@ Gate valve@ Target c hamber ( B)

Fig. 1.

@

0
@

@

= @

Schematic drawing of RIKEN 200 kV low current implanter.

Table 1.

Types and characteristics of implantation systemcomponents presented in Fig. 1.

Io n so urce

rf type (home-made)Nie lsen type (Danfysik Model 910)
hollow ca th o d e type ( Dan fisik Mod e l 9 1 I A)

Accelera tor va I tage

30 - 200 kV

Mass a naly zer

Magn e t of 90° (m ass 9 0 at 200 kV )X-Y scanner~5

Beam curre nt a)~30 IlA (As, Sb)

Pumping

Two se ts of oil diffusion pump with rotary pump ,kH z(X), ~0 .2 kHz(Y) (trianglar waves)

one se t of molec ul ar pump with rotary pump
Typical pressurea) details in Table 2.

~2 X 10 - 6 Torr during implantation

9

The present implanter has the advantage of installing three types of ion sources and owning
three target chambers. The following is the description of these equipments.
A variety of ion sources can ionize most of the elements. The rf type ion source has beennormally used for gaseous elements such as nitrogen, oxygen and argon. Recently, a new methodof utilizing the ion source has been tried for producing metallic ions. For this purpose, the volatilechloride such as TiCl4 or SiCl4 was introduced in the discharge chamber. By using chloride, theerosion takes place at the extraction canal made of aluminum or copper, and the elements of thecathode electrode are included in the ion beams.
typically obtained.

A beam current of a few microamperes is

Heavy ion sources of the Nielsen and hollow cathode types can be used for the discharge ofmost of gaseous and metallic elements. Each of the ion sources has its own heating element toallow precise temperature control of the charge oven. The charge oven temperature can be raised
up to 900°C with the Nielsen type ion source and up to 1600 ° C with the hollow cathode typeion source.

Table 2 presents the typical beam current , the type of the ion sources used to get

the beam and the materials inserted in their furnaces.
In this implanter there are three target chambers.

Chamber A, which is placed at the normal

position of the ion implanter, has six or four target holders for performing ion implantation at theambient temperature. The target temperature rises from room temperature by the heating effectof the ion beam itself. Maximum implanted area of the sheets is 33 X 30 mm 2 (10 cm 2 ) for six
target holders and 40 X 50 mm 2 (20 cm 2 ) for four target holders.
Chamber B at the backside of chamber A to the ion beam incidence is provided with one
target holder for implantation at any target temperature from liquid nitrogen temperature up to
about 400°C.

The maximum size of a sheet mounted on the holder is 30 mm in diameter.

The

exchange of the specimens can be easily done because the volume of the chamber is very small.
Chamber C located between the accelerator and the magnet is also used as the gate valve. A
pressure of about 2 X 10- 6 Torr can be reached in the chamber by using an oil diffusion pumpbelonging to the original implanter after an initial pumping down to about 10- 3 Torr by an oil
rotary pump. A cylinder or a plate can be mounted on the target holder. The maximum size ofthe cylinder is 40 mm in diameter and 30 mm in length , and that of the plate is 30 mm in widthand 20 mm in length. The ion beam is scanned in one axis with a trianglar wave voltage and theholder is moved in the perpendicular axis so that the ion beam can strike on the specimen surface
uniformly; A cylinder can be rotated at 0.2 to 3.7 r.p.m. and a plate can be moved at 0.4 to 7.4mm/min. For ion implantation without mass-separation to be carried out, the amount of thedesired elements present in the ion beam must be known well. In this implanter, elements of
the ion beam can be estimated by using a magnet before performing ion implantation.
The ion implanter has been used for modification of the near-surface region of semiconductors,
metals and insulators. Many studies have been made of the physical, electrical, mechanical,
tribological and electrochemical properties of implanted materials; depth profiles and lattice locationof implanted elements, radiation damage, conductivity, hardness, wear, friction, corrosion, etc. of
implanted materials.

10

Typical beam current obtained by the RIKEN implanter.

Table 2.

Ion source a)

Element

Current (/lA)

CompoundB

5

B + B2 0 3

C5

CO 2 , CO

A

B

C

N

20

Elem .

A

B

C

°

10

Elem .

A

B

C

AI

20

Elem. , AICI 3

B

C

Si

10

SiCI 4

P

5

P2 Os

CI

50

Chloride

Ar

30

Ti

20

Cr

20

Ni

20

Cu

C

A

B
A

B

C

Elem.

A

B

C

TiCI 4A

Elem ., CrCI 3

B

C

NiC I2B

20

CU 2 CI 2

B

Zn

30

Elem.

B

Ga

10

Gal 3

B

Ge
As

30

Ge + Ge Z 0 3

B

Elem.

B

AgCI

B

20

El em.

B

Elem.

B

I

SnCI 4

B

Sb

30

Elem.

B

Te

20

Elem.

B

30

Iodid eB

0.1

H2 PtCI 4

B

Ag
Cd
In
Sn

Pt
a)

A: rf t y pe,

13 : Nie lsen t ype,

C:

Hollo", cath od e t y pe.

C

11

II .

OPERATION OF ACCELERATORS

1.

Machine Operation

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

The cyclotron was operated on the 24 h a day basis during the period from Oct. 23, 1980 toOct. 22, 1981.
Statistics of machine operation time is shown in Table 1. The total net beam time of 4098.5
h is slightly , i.e. 3.2 % (257.1 h), shorter than that of the last year. This decrease in beam time isdue to scheduled shut-down.
Table 1.

Machine operation.
Oscillator

Ion-source

BeamReading of time meter on Oct. 23, 1980

66807.1 (h)70893.8 (h)37228.7 (h)Reading of time meter on Oct. 22, 1981

71424.475610.8

41327.2

Difference

4617.34717.04098.5Percentage of 365 days

52.7 %

46.8 %

53.9 %

Schedule in this period
Beam time

226 (days)

Overhaul and installation work

53

Periodical inspection and repair

26

Vacation and holidays

47

Other scheduled shut down

13

Table 2 shows the beam time allotted to various activities in this period.

Although thescheduled beam time (5194 h) was decreased by 284 h compared with that of last year, the beamtime allotted to nuclear physics groups was slightly , i.e. 18 h increased and the time to groups offields other than nuclear physics was decreased by 302 h compared with that of last year.
Table 3 shows the distribution of the scheduled beam time among particles accelerated. In
this period, the beam time of highly charged ions such as 0 5 + and Ne 6+ was greatly increased.
The heavy ions were produced and accelerated using a new improved heavy ion source 1) during
this period.
Figure 1 shows the beam time of heavy and light ions over the past 7 years.

Requests forheavy ion beam continued to increase and cyclotron was operated to accelerate heavy ions formore than 75 % of the total scheduled beam time over the past 4 years.

12

Table 2.

Scheduled beam time and subjects of activity in the period XVI.
Heavy ion

Ligh t particles

Total

Nuclear reaction

2722 (h)240 (h)2962 (h)In-beam spectroscopy

525

24

549

61

28

89

Nuclear chemistry

6

262

268

Fields others

Radiation biology

185

15

200

than Nucl. Phys.

Solid state physics

262

237

499

330

22

352

0

28

28

0

82

82

5

160

165

4096

1098

5194

Subject

Nucl. Phys.

1 RI production

Inner atomic shell
excitation study
Study of radiation damage
fuel study{ Nuclear
RI production

Outside users

Total

78.9 %

Percent in total

21.1%

100 %

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

Maintenance , operation and engineering
Exchange of ion sources

79 (h)

Machine inspection and repair

624
703

Total

Table 3.
-- ~ --

Distribution of beam time among particles accelerated.

-

Particle(h)(%)

Particle

(h)

(%)

P

241
11
271
581
336
1154

4.7
0.3
5.3
11.3
6.6
22.4

N 5+

728
450
1316
4
48
5194

14.1
8.8
25.5
0.1
0.9
100.0

d
3He++
4He++
C 4+
N 4+

a) Newly accelerated ions.

0 5+
20 Ne6+15 N4+a)
19 F6+a)

Total

13

---..~-><:-

Heavy ionLight particles
Totalo1974 '75 '76 '77 '78 '79 '80 '81

Calendar year

Fig. 1.

The cyclotron beam time history.

Reference
1)

T. Kageyama, K. Ikegami , and I. Kohno: IPCR Cyclotron Progr. Rep. ~ 4 (1980).

14

II -2.

Operation of Heavy Ion linear Accelerator

M. Odera

After achieving the test beam acceleration in 1980, effort has been paid to set up and tune the
RF control system which is assisted by a computer for synchronized operation of the whole six
amplifiers coupled with cavities.

In the course of a running test of the individual cavity excitation,a serious vacuum leak and damage was generated in the driving mechanism of the shorting plate of
the fourth cavity.

Before completion of repair of those defects , acceleration of the singly charged

nitrogen ions was tried in March 1981.
Report. I)

The results are given in another paper in this Progress

Energy resolution was 1.7 (fc) at the exit of the third cavity without use of the chopperor the buncher.
In that operation some defects were found in the power supplies for the amplifiers and othersmall components of the accelerator such as the beam probe containers or cavity signal pick-ups.
Also distribution of the probes for beam diagnosis along the beam line was found desirable to bemodified.

After improving those parts, acceleration through all the cavities was realized in

October.
A pulse excitation method varying the width and repetition rate by a large factor during thestarting-up period of the cavity excitation was found to be a convenient means to search resonanceof the resonator to the given frequency and to overcome the multipactoring phenomenon.
Hitherto, the method of cw excitation at a slightly detuned frequency has been used to cross themultipactoring region.

The pulse excitation is also effective for degassing of the cavities at therelatively good vacuum.
In order to get quickly information of the characteristics of the beam being injected, a simple
pepper-pot device was fabricated and tested.

In combination with a profile monitor, it gives arough estimation of the emittance of the beam in not complete but intuitive way.

It is convenient

to indicate to the operator the effect of his adjustment of the parameters of the injection beamline on the beam.

A computer program for orbit analysis gives the beam trajectories expected byinjection of the beam for assumed parameters of the magnetic lens system in the accelerator on
the CRT at the operator console.

Also another emittance device which sends digitized signals toallow direct presentation of the emittance figure on the CRT is equipped in the injection line togive a complete information of the beam if necessary.

Automatic range switching multichannel

current monitors were designed and installed in the control room.

The monitors send analog

signals of beam current on the slit blades or beam stoppers to the control console.
sensitivity is

10- 10 A.

Maximum

For the profile monitors which require higher sensitivity, another amplifiersystems are provided.
A beam intensity attenuator using the slits with V-slots was fabricated and installed in the
beam line downstream of the last cavity.

It enables us to attenuate the beam current by a factorof 10- 5 in combination with a quarupole magnet in front of it.

It allows use of a very small

current of small diameter for some experiments.
Though the transmission efficiency of the beam through the accelerator is to be improved

15

further, and the beam buncher and chopper are not working yet, use of the beam was started from
November.

For a while, only the elements in gaseous state will be accelerated.

In the test bench, PIG ion source equipped with a sputtering electrode is producing ions ofsolid elements.
desirable.

However, some improvements in the intensity of highly charged ions are still

The first stage of the ECR ion source was completed in early summer and gave singly-

and doubly-charged ions of Argon in summer.

In that test an uneven spatial distribution of plasma

density was found in the ionizing chamber, and the extracted current was smaller than expected.
It was disassembled to find the origin and a suitable solution for the insufficient performance.
There occurred two troubles in the injector high voltage power supply. One is a damage inthe high frequency transformer of the 50 kHz generator which supplies power to the Cock croftWalton voltage multiplier.

Another is the damage of one of the rectifier stacks.

Reference
1)

T. Kubo, T. Kambara, Y. Miyazawa, M. Hemmi, Y. Gono, T. Inoue, T. Tonuma, M. Kase ,M. Yanokura, Y. Chiba, T. Fujisawa, and M. Odera: p. 128 in this report.

16

II -3.

T ANDETRON-Operation

H. Sakairi, E. Yagi, A. Koyama, T. Urai, and Y. Yamada

During eight months from March to October, the machine was operated for 74 days in total:
37 days for experiments and 37 days for tests. The machine time for the tests was frequently
required because of initial troubles.

Part of the machine time for experiments is expected toincrease hereafter.
Ions of helium, carbon, nitrogen, silicon and gold were accelerated this year. Some of theconditions of operation and resulted beam intensity are shown in Table 1. For helium and siliconions, the negative ion beam intensity and the terminal voltage were chosen to be the same for thedifferent charge state of the ions , therefore the difference of accelerated ion beam intensity
between the different charge state is considered to depend mostly on the efficiency of charge
exchange.
Table 1.

Negative Ion

Terminal

Acceleration

Beam

Ratio ofbeam Intensity

voltageenergyintensity

the number

(IlA)

(MV)

(MeV)

(PA)

of ions

}

0.6

0.35

0.7
1.05

0.2
0.06

0.15

}

0.8

0.5

1.0

0.5

1

1.5

0.1

0.1

}

9

0.8

2.4
3.2
4.0

2
0.8
0.25

0.27

}

5
5

1.4
2.5

0.22
0.18

Ion

He+
He 2 +He+
He 2 +
Si 2 +
Si 3+
Si 4 +Au 3+
Au 4 +

Operating conditions and beam intensity.

0.35
0.5

0.08

Troubles occured this year in the following parts: the logic circuit of the RF driver for the
Cockcroft-Walton rectifier, the rectifying circuit of it, the controle circuit of Q-1ens and the lithium
vapour canal.
For the maintenance of the TANDETRON, Beam Analysis Center took the responsibility
supported by Metal Physics Lab., Solid-state Chemistry Lab. and the Work Shop.

17

III.

RESEARCH ACTIVITIES
1.

Nuclear Physics
1.

Bare Potential DWBA for (d, p) Reactions

M. Ichimura and M. Kawai

NUCLEAR REACTIONS 160(d,p)170 , 4OCa(d ,p) 41 Ca,

J[ Bare potential DWBA, Coupled channel Calculations.

Justification of DWBA is a long standing problem.

From analysis of the (p ,p') reaction ,Perey and Satchlerl) claimed that DWBA was valid even when strong coupling between the entrance
and the exit channels did not warrant the first order approximation to their coupled channel (CC)equations, because the distorting potentials used in the DWBA were the optical potentials andtherefore they contained higher-order effects of the coupling.
Starting with the CC formalism , Ascuitto et al.,2) however, questioned the validity of"conventional" DWBA in which the optical potentials were used for the distorting potentials inboth the entrance and the exit , channels , and proposed a new type of DWBA in which the opticalpotential was used only in the entrance channel while in the exit channel use was made of the barepotential, the distorting potential used in the CC calculations. Such type of DWBA was called barepotential DWBA by Kubo and Hodgson 3 ) and was shown to work reasonably well for someheavy-ion inelastic scatterings. One can equally consider another type of bare potential DWBA in
which the bare potential is used in the entrance channel and the optical potential is used in theexit channel.
A question is then in what situation the bare potential DWBA works. Since strong coupling
effects between rearrangement channels have been demonstrated by several authors,4 ) ,5) it isinteresting to investigate the validity of the bare potential DWBA for the transfer reactions. Here
we study this problem for the cases of 160(d,p)170(2s) and 4oCa(d,p)41Ca(2p) reactions, whichhave been studied in the previous CC analysis 5 ) with the finite range form factors and thenon-orthogonality terms.
For the present purpose, we considered the CC cross sections of our previous results 5 ) as the"model" experimental data. With the criterion of best reproducing the "model" elastic crosssections, we searched partial wave (e)-independent local optical potentials, u ct pt and u~Pt , forthe deuteron and the proton respectively , which were assumed to have the same functional formof the bare potentials used in the CC calculations. The parameters for u ct pt and u~Pt obtained by
the search are listed in Table I together with those for the bare potentials , u~are and u~are , for thed'Emteron and the proton respectively.
In Fig . 1 the (d,d) and (p,p) cross sections on the oxygen and calcium nuclides obtained by
the bare and the searched optical potentials are compared with the CC results. The figure clearlyshows the possibility of finding f-independent local optical potentials with reasonable parameters,
which reproduce the CC results.

18

Table 1.

oPotential parameters.
a'(fm)

rc(fm)

1.58

0.777

1.30

1.734

0 .661

1.30

11.1

1.250

0.143

1. 25

0.566

12.2

1.365

0.293

1.25

0.966

0.846

16.4

1.480

0.492

1.30

0.935

0.864

19.5

1.585

0.422

1.30

1. 250

0.470

1.25

1.332

0 .3791.25

Vo(M eV)ro (I'm)a(fm)Wo(MeV)ro (fm)udbareuct pt
ubare
p
uopt
p

118 .00. 9340.79 2

5.95

127.1

0.87 2

0.831

6.43

49.3

1.2 50

0.580

43.8

1.276

U h ;lfc
d

120.7

ud

129.1

o pt

u

52.7

1.200

0.650

1 1.0

uo

46 .5

1.279

0.704

21.5

bare
p
pt
p

The potential form is given by

where Ue(r) is the Coulomb potential due to a uniformaly charged sphereof radious r e A 1/3 .

10. 0

~,

.; /
/
/

"

/

1.0

/

/
/

/

( d) .IICa ( p, p) 4l Ca J·;c.m. = 14.67 MeV /
0.1

I

/~~

/

/

( b)

10.0

-

j
0 ( p, p ) 11- 0
j . ....
j ..
Ec.m.= 11.54Me\j .
Ii

j

/
/
/
/
/
./

1.0

O. 0 1 L-..l.---L---L.-....L...-.L.-L--L----L.:--l....-..L.-J----'----'---'--....L....-~--'
30

60

90

120

150

180

0

30

60

90

120

150

180

l1c. m.

The Rutherford ratios of the elastic scattering of (a) 160(d, d) 16 0,(b) l70(2s)(p, p) 17 0(2s), (c) 4oCa(d, d) 4oCa and (d) 41Ca(2p)(p, p) 41 Ca(2p).
Fig. 1.

The results

obtained by the bare potentials (dashed curves) and the searched optical potentials (dottedcurves) are compared with the CC results (solid curves).

19

We then performed four types of DWBA calculations of the (d,p) cross sections in which thedistorting potentials were (i) (u~are , u~ a re) , (ii) (UdPt, u~Pt), (iii) (UdPt, u~are) and (iv) (u~ are ,u~Pt), respectively.

The type (i) corresponds to the first order Born approximation in the CC

formalism, the type (ii) to the "conventional" DWBA and the type (iii) and (iv) correspond to two
different types of the bare potential DWBA in which the bare potential is used in the channel p andd, respectively.
The results of the four types of DWBA are compared with each other in Fig 2. From
the figure one sees that none of the DWBA's reproduces the "model" (d ,p) cross sections well.
Comparison between Fig. 1 and Fig. 2 shows that the searched e -independent local opticalpotentials may reproduce the asymptotic behavior of the distorted waves of the CC calculation
but they are inadequate for including the channel coupling effects on the (d,p) cross sections.
The CC effects associated with the transfer process in light-ion reactions seem to bring aboutstronger non-locality or f-dependence for the effective potentials which well reproduce the distorted
waves of the CC calculation even in the inner region as well as the asymptotic one. The above
results are in sharp contrast to the case of the heavy-ion inelastic processes.

160 ( d, p ) 170 ( 2s ) J·.'c.m.= 1O.49 MeV

10.0

,,
,
\
\

\
\
\

10. 0

'. (/\.'\\(1 "~

\)

<fl

1. 0

'is

'--

';S

E

~~

Ll

<fl

'--

Ll

E

t

1. 0

\\
f'

t

0.1

~

O. 1 L-L.---L.-.....L.-.I...-..l~L...l..-.J..--1--L...---L-..J..-.J'---1J.L---L-J.-l......J
o
30
60
90
120
150
180
8c .m .

0

30

60

180

Fig. 2.

The (d, p) cross sections of (a) 160(d, p) 170(2s) with Q-Value Q = 1.046 MeV
and (b) 4oCa(d, p) 41 Ca(2p) with Q = 4.19 MeV. The CC results are shown by solid curves.
The results of the four different types of DWBA are compared. The type (i) is denotedby (--), the type (ii) by (-----), the type (iii) by ( ..... ) and the type (iv) by ( _ . - ).

References
1) F. Perey and G.R. Satchler: Phys. Lett. , i, 212 (1963).
2)
3)
4)

R.J. Ascuitto, J.F. Petersen, and E.A. Seglic: Phys. Rev. Lett., 41,1159 (1978).
K.-I. Kubo and P.E. Hodgson: Nucl. Phys., A366 , 320 (1981).
T. Ohmura, B. Imanishi, M. Ichimura, and M. Kawai: Prog. Theor. Phys., il, 391 (1969); 43,347 (1970); 44,1242 (1970); R.S. Mackintosh: Phys. Lett. , 44B, 437 (1973).

5)

B. Imanishi, M. Ichimura, and M. Kawai: Phys. Lett., 52B, 267 (1974).

20

III -1-2.

Mass Diffusion Coefficients In the Adiabatic Approximation

S. Yamaji, A. Iwamoto,* K. Harada,* and S. Yoshidar

NUCLEAR REACTIONSMicroscopic calculation of mass diffusion coefficients,]

llinear response theory, two-center shell model.

During the past several years, relaxation phenomena in deep inelastic collisions (OIC) havebeen extensively studied both experimentallyl) and theoretically.2)

The mass transfer in DIC is

described on the basis of a non-perturbative statistical treatment which leads to the Fokker-Planck
equation for the mass number of projectile-like nucleus AI' 3) - 7)

The diffusion coefficient 0A in

the equation is one of the important quantities for this treatment.
Experimentally, the value of DA has been obtained by the use of the relation DA = X(8)2/[16 In2 T·m t (8)] with the interaction time estimated on the basis of classical models. 3 ), 4)Thewidth X(8) is obtained from the experimental mass distribution at the deflection angle 8, by assuming
the distribution to be gaussian.
Theoretical calculations on D A have been performed by serveral authors 3 ) - 6) in the sudden or
frozen density approximation.

In these treatment , aside from the formation of a neck or window,

the two fragments essentially remain spherical.

However , the fragments separate with the kinetic

energy less than the Coulomb energy of two touching spheres.

This suggests the formation oflarge deformation and the use of adiabatic basis is required for the description of the massfragmentation.
Therefore , in the present work, we calculate DA microscopically using the linear response
theory,7) which is formulated for an adiabatic basis. By neglecting the coupling between masstransfer motion and other motions such as radial and deforming motions , the same type of the
Fokker-Planck equation as that in Refs. 3 and 4 is used under the condition of the overdamped
motion for the mass transfer, which has been justified numerically for the 63 Cu + 197 Au reaction. S )The diffusion coefficient in this formalism is expressed as(1)

Here , T stands for the temperature.

The friction coefficient 'YA corresponding to the mass transfer

motion is expressed in terms of eigenfunctions I i> with eigenvalues ej in the two-center potential
V by

(2)

* Japan Atomic Energy Research Institute.

21

The two-center potential V depends on the distance between centers of masses of two nuclei R,
deformation of two nuclei 0 (0 = 0 1 = O2 ), neck parameter E and mass number Al and ~, and its
specification is given in Ref. 9.

The chemical potential A is determined by the conservation of the

The smearing width r is introduced to take into account the finite

total number of nucleons.
wid th of the energy levels.

The calculations are performed for the reactions 20Ne + 27 Al at 120 MeV, 16 0 + 58Ni at 92
MeV, 32S + 50Ti at 131 and 166 MeV, 40Ar + 109Ag at 288 MeV, 40Ar + 197Au at 288 and 340 MeV,
40Ar + 232Th at 279 and 388 MeV, 63Cu + 197Au at 365 and 443 MeV, 84Kr + I6 5Ho at 714 MeV,
86Kr + I97Au at 620 MeV, 84Kr + 209Bi at 714 MeV and 136Xe + 209Bi at 1130 MeV.
estimation of the temperature T, we use the relation 3)
T = 3.46~ E * / A

For the(3),

where the intrinsic energy E * is assumed to be the difference between the incident energy andmeasured average kinetic energy of DIC products.1)

The dependence of the diffusion coefficient

per unit temperature DA IT on the parameters Al ' T and r are examined and the results show thatit does not depend much.

In the further calculation, therefore, Al is fixed to be the projectile

mass number, T to be the average of temperatures determined by Eqn. (3) in the cases of morethan two different incident energies and r to be 0.4 hwo (hwo = 41 A- I /3 MeV).
0 .25

CAL

1

Present 8=0.0 [=0.6... Ref [3.4J• Ref. [5J

x Ref. [6J

I

U

Ne

0 S

Ar

AI

Ni Ti

Ag

+ ++

~ 0.15~o(3.0) (2.3)(2.0)(2 .6)

C\J~u 0. 10
to

+

(3.0)

!

0..

f-.........

Xe

+

0.05

Bi

c1

(3.4)

150
mass number of compound system

Fig. 1.

Comparison between experimental and calculated massdiffusion coefficients per unit temperature. The present
calculated results and experimental ones 3), 4),11) are shown by
the points - and @.

The other points ... , • and X show thecalculated results taken from Refs. 3 and 4, Refs. 5 and 6,
respectively.

The values of temperature estimated from Eqn.

(3) are written in the parentheses in units of Me V.

The averagevalues are taken in the cases when more than two different values
exist for both experimental and calculated results. 3), 4) The
values calculated at S = 0.5 are taken from Ref. 6.

22

The dependence of DA IT on the parameters 8, Rand c are also examined and the results showthat it is strong.

The smooth increase in DA IT is found with the increase of 8, the decrease of R

and the decrease of c .

This trend is consistent with the physical intuition that the mass transfer

occurs more rapidly under the situation of deeper penetration of two nuclei and larger neck-radius.
The calculation is found to give a rough magnitude of the experimental result.
Since the calculated values of DA IT depend strongly on R, we have to fix the value of R inorder to compare the calculated results with the experimental ones.

For that purpose, we assume

that the mass transfer occurs while two nuclei form a rotating composite system at R = R J + R2

(Ri = I.] 8 Ail / 3 fm) in the same way as in Ref. 4.

A comparison at R = RI + R2 shows that thevalues of c = 0.6 and 0.8 seem to give overall good fits to the experimental results for the cases of
8 = 0.0 and 0.2 , respectively.

The latter value of 8 is the average of the deformations which are

obtained at the distances of the closest approach in the calculation for the 120 MeV 20Ne + 28Si
reaction. 10)
In Fig. 1, the present calculated results are compared with both the experimental ones 3), 4), 11)
and the other calculated ones. 3) - 6)

A dashed line is drawn between the origin and our

calculated value for the reaction 136Xe + 209Bi to help to see the trend that both the calculated andexperimental values of DA IT increase with the mass number of the compound system A.
Agreements between our calculated and experimental results are satisfactory in view of theuncertainty of experimental results which comes from the uncertainty in the determination of theinteraction time. It should also be noted that our calculation based on the adiabatic approximationand other ones 3)- 6) based on the sudden approximation give rather similar results.

ReferencesI)

M. Lefort and C. Ngo: Ann. Phys., 1, 5 (1978).

2)

H.A. Weidenmuller: Progr. in Particle and Nucl. Phys., l, 49 (1980).

3)

S. Ayik, B. Schurman , and W. Norenberg:

4)

G. Wolschin and W. Norenberg: ibid. , A284, 209 (1978).

5)

C.M. Ko, G.F. Bertsch , and D. Cha: Phys. Lett. , 77B, 174 (1978).

6)

M. Prakash, S. Shlomo , V.S. Ramamurthy , S.S. Kapoor, and S.K. Kataria: ibid. , 988, 413

Z. Physik , A279, 145 (1976).

(1981 ).
7)

H. Hofmann and PJ. Siemens: Nucl. Phys. , A275, 464 (1977).

8)

S. Yamaji, A. Iwamoto , K. Harada, and S. Yoshida: Proc. Intern. Conf. on Nucl. Phys. ,Berkeley (1980).

9)K. Sato , A. Iwamoto, K. Harada, S. Yamaji, and S. Yoshida: Z. Physik, A288, 383 (1978).

10)

K. Sato, S. Yamaji, K. Harada , and S. Yoshida: ibid., A290, 149 (1979).

11)

S. Yamaji:

IPCR Cyclotron Progr. Rep., l.l, 42 (1979).

23

III - 1 -3.

Non Perturbation Effect on the Nucleon Transfer Amplitudes
in Close Contact Heavy-Ion Collisions

N. Takigawa , T. Uchiyama,* and K. Sato[

NUCLEAR REACTION
DIC , nucleon transfer amplitude non
perturbation effect, Green's function.

J

In deep inelastic heavy ion collisions (DIC) the scattering nuclei come in close contact with each other for along period.

Accordingly, the amplitudes of single nucleon transfer , which govern the mass transport coefficients ,cannot be estimated by the lowest order perturbation treatment. I), 2)

In order to go beyond the lowest order

perturbation approximation we introduce the single particle Green's function G(t , to) that describes the time
evolution of a nucleon in the unified mean field created by the scattering nuclei.

The matrix element of G(t, to)with respect to the i-th and j-th single particle states of the scattering nucleus A, <PAi and <P Aj ' is given by
GAjAi (t,tO )=~ < <I>Ajlxa >< xa I <l>Ai > exp { - iEa ( t-tO )/ft + ieAjt/ n - ieAit O/ n}a==O.~< <I> Al.Ix a >< x a 1<1> Al. > exp{-i ( E a - e k 1 )( t-tO ) / ft},
IJ a

(1)

where 1 XC\' > is the a-th single particle bound state of the combined system , EC\' is the corresponding eigenenergy,
and eAi is the energy of the single particle state 1 <PAi >.

We use all the bound states of the colliding nuclei A

and B, i.e. {I<p Ai>} and {I <PBk >} , as the working space and deal with the scattering in the static approximation.
Namely, we disregard the change of the relative distance between the colliding nuclei during the period when the
nucleon transfer takes place.
then given by

The transition amplitude tki for the transfer of a nucleon from I <P Ai> to I <PBk > ist k i ( t ) == ( l/ift ) f~o ds {~ < 1/7 B k ( s ) 1U A (:.. -~ A ( s ) ) 11/7Ai ( s) > GAjAi (s, to )+f < 1/7Bk ( S ) I UA (~-~A ( S )) I ¢Bl ( S »GBIAi ( S,tO ) }'where U A is the single particle potential of the fragment A, and ¢ Aj (s) = <P Aj X exp { - e Aj t/fi } etc.

(2)
The lowest

order perturbation approximation for tki corresponds to putting Gji(s - to) == G AjAi (s, to) ~ Dji and G BlAi (s, to) ~o in Eqn. (2).

In the following we study the behavior of the Green's function G n.. (t) by considering one

dimentional scattering problem.
50 MeV , 1.2 A l / 3
respectively.

We assume the Woods-Saxon potential for each separated fragment and choose

fm (A being the mass) and 0.65 fm to be the values of depth, range and diffuseness parameters,

The separation distance between the centers of the scattering nuclei, R, is chosen so as to correspondto the distance of closest approach for typical partial waves of DIC.
In Fig. 1 we consider a symmetric system, i.e. Al = A2 = 90.
single particle energy spectrum of each separated fragment.
system when R = 12.0 fm.

The left and the right of Fig. 1 (a) show theThe middle shows the energy spectrum for the unified

Each of the energy levels can be distinguished by the number of nodes of thecorresponding level of the separated fragment and the paIity.
the potential barrier VB between the scattering nuclei.

The thick bar at - 27.8 MeV represents the height of

Figure 1 (b) shows the absolute values of the diagonal

matrix elements of the corresponding Green's function as functions of time. Roughly speaking, each of IGii(t - to)1
behaves like Icoswi(t - to)l.

The frequency can be easily estimated by two level approximation , i.e. by keeping

only the parity doublets Xi+ and Xi _ that correspond to <PAi in the sum over a in Eqn. (1).

* Department of Physics, Tohoku University.

In this approximation,

24

0.4 2 =90

R= 12.0fm.-1,+ .4 2

6

,

5

c

A , = 90
J

6

10
,,

.'\, (= 90 ) + .'1 2 (= 90 )5/

1.0 ~::--"====::-::-::_=__-_------------IGIII

/

>

20

0.8

~

-

1< = 12.0fm
N. = Hz = 5.4 fm

4

4

VB

..:- 0.6
I

30

IG I
H

3

-,

3

,

40

IG 55 ]

si 0.4\ jlG.

1

0.2
2~~----\/

2000~-7---~--~--~---+--~6--~~~8~--~9--~10

1- - - - - 50

Fig. 1 (a).

t - t o (2 x l 0 "sec)Energy spectra for separated

fragments and for the unified system.
Symmetric system.

Fig. I (b).

Matrix elements of thp. single particle

Green's function as functions of time.

IG ji ( t - to ) l::: aii lcos { O!2) t.Ei ( t - to )/ h} I
and IG B1Ai ( t - to JI::: alil s in { ( 1/ 2) t.E i ( t - to )/h} I,
where 6Ei is the energy splitting between the parity doublets.

(3)This and Fig. 1 (a) explain the feature of Fig. 1 (b)that the frequency of IGnC t) I becomes larger as the energy of the single particle state cPAi becomes higher. The
remarkable point is that the matrix elements of the Green's function with respect to high lying states, which
dominantly contribute to the mass transport, show a few oscillations within the typical reaction time (~2 X 10- 21sec) of DIC. This clearly shows the importance of non perturbation effect in close contact heavy ion collisions.
The energy difference between any parity doublets becomes smaller for larger separation distance R. This leads
to less oscillations in the matrix elements of the Green's function. Accordingly, the use of the lowest order
perturbation treatment becomes more justifiable . Our calculation shows that only I G 66 I has an oscillation within
the time interval of 2 X 10- 21 sec when R = 15 fm .
Figure 2 shows the energy spectra and the matrix elements of the Green's function for a very asymmetricsystem , i.e. Al = 40 and A2 = 232. The separation distance R has been chosen to be 12.6 fm. Only the matrix
elements with respect to 8 single particle states of the heavy fragment B (A 2 = 232) are shown. Their timedependence is more complicated than that for the symmetric system. This reflects the lower regularity in thelevel sequence.

Without question, however, Fig. 2 again shows the necessity of taking the Green's function into

account when we estimate the nucleon transfer amplitudes for DIC. A difference from the case of symmetricsystem is that the non-diagonal matrix elements of the Green's function have to be properly taken into accountfor the scattering of very asymmetric nuclei.

In this report we have demonstrated the importance of non perturbation effect on the nucleon transfer
amplitudes in close contact collisions. The mass transport coefficients will be characteristically influenced if thenon perturbation effect on each single nucleon transfer amplitude adds up coherently. Such coherent process
is expected to be important in close contact collisions of, especially, identical and nearly identical nuclei. This isbecause, in such collisions there is an intimate correspondence between the energy spectra of the scattering nuclei.
As one of such examples, we compare in Fig. 3 the single particle energy spectra of 92Z r and 98Mo in the actual 3
dimensional case calculated for the single particle potential given by Eqns. (2.181) and (2.182) of Ref. 3.

25

R= 12.6fm.4, +.4 2.4 = 232

0

", ,

/

,,

7

5

,,

8

10

.4, =40,

Al ( = 40 ) + A2 ( = 232),)

R= 12.6fm
R , = 41fm , R2 = 74fm

,IG"I_________ ~ IG 22 1

4

/

20

4--~·

40

'-'-'-'-~ ' IGJJI

6 - - - - -_ _ __IG.. I'-__ -----2
0. 2

3--2----~_----::"'---- 1

o 00:----=------:-2----:3~-.....
4 -~5----:6----::---8::----:':-9--:'10
t- to (2 x 10 U see )50

Fig. 2 (b).
Matrix elements of the single particle
Green's function as functions of time. Only thematrix elements with respect to 8 single particle
states of the heavy fragment B (A 2 = 232) are shown.

Fig. 2 (a).
The same as Fig. 1 (a).
Asymmetric system.

Prot on0~ ~ MoNeutronPr ot on0

Og~ ---

O h ~ ---

QhIYz - - Id % ___2s ~ ___
Id %- - -L

Q)

Og%- - -

w

L

10

1p Yz
Of %

--Og% - - -

w

m

m
15

Of %- - -1p)1 _ - 1PYz
Of %Ot Y2 - - -20

Fig. 3.

Id % - - -Ip ~ ---

>

IP%=
Of Yz

2s ~

Og %- - -Ip ~ ---~ 10

I d% ___Og )1 _-_-

5

O g~ ---

OgYz - - -Neut ron

Id %- - -I d% - - -

5

~~ Zr

1p ~ ---Of )1- - 15

Of Yz
IP Yz -Of Y2 - - 20

Comparison of the single particle energy levels of 92Z r and 98Mo.

References
1)
2)
3)

K. Sato, N. Takigawa, and S. Yoshida: Soryushiron Kenkyu (Kyoto), 63, C-38 (1981).
D.H.E. Gross and K.M. Hartmann: Preprint HMI (1981).
A. Bohr and B.M: Mottelson: Nuclear Structure, New York, Amsterdam, Benjamin,.!., 239 (1969).

26

III-1-4.

Full Finite-Range CCBA Analysis of the22

Ne (p, t)

20•

Ne Reaction

T. Takemasa

NUCLEAR REACTION

22Ne(p , t) 2oNe , E = 39.8 MeV ; ground stateJ[ rotational band , finite-range , zero-range, CCBA .

Exact finite-range (EFR) coupled-channel Born approximation (CCBA) calculation for thereaction 22Ne(p , t) 2oNe at E p = 39.8 MeV to the 0+ , 2+, and 4+ states of the ground-state (g.s.)
rotational band has been carried out. The analysis of this reaction has already been attemptedby Olsen et a1.l) and by King et a1. 2) within the framework of zero-range (ZR) CCBA , who showedthat the effects of indirect transitions via inelastic processes are of importance in this reaction.
No physical justification, however, has been given to the ZR assumption. The purpose of the present
work is to investigate the finite-range effects in performing EFR calculation for this reaction.
The spectroscopic amplitude was taken from the work of Olsen et aLl) , where they adopted
the adiabatic assumption for the rotational wave function of the g.s. members, and the internal
wave functions were constructed from Nilsson-BCS model. The interaction responsible for the
two-neutron transfer process was assumed to be a finite-range , central, spin-dependent force
between the proton and the two individual neutrons.

The triton wave function used in thiscalculation was obtained by a variational calculation. The depth of bound-state potential waschosen to give each bound neutron half of the two-neutron separation energy using a Woods-Saxon
well with standard geometry (ro = 1.25 fm, a o = 0.65 fm).

The inelastic matrix elements usedwere obtained on the basis of macroscopic rotational model.

The calculation included 0+ - 2+

inelastic coupling in the incident channel and 0+ - 2+ - 4+ inelastic coupling in the exit channel.
The nuclear deformation parameters {32 and (34 for neon isotopes were taken from an analysis ofproton scattering. 3 ) For comparison , the ZR-CCBA calculation was also carried out by using theGaussian triton wave function. The parameters used in the ZR-CCBA calculation were the sameas those used in the EFR-CCBA calculation.
The results of the EFR-CCBA and ZR-CCBA calculations are shown in Fig. I together with thedata of Olsen et al. The single normalization constant was chosen to give the best visual overall
fit for the 0+ , 2+ , and 4+ curves. The magnitude of the experimental cross section is about afactor of 2 larger than that calculated in the EFR-CCBA. It is evident from Fig. I that the
EFR-CCBA calculations give a good reproduction of the experimental relative strengths of the threetransitions.
A comparison with the ZR-CCBA calculations shows that the finite-range effect improved
agreement with experiment in the shapes of angular distributions of the 0+ and 4+ transitions.
However, the agreement between the 2+ curve and the experimental data is rather poor. In order
to find out the reason for the discrepancy between the experimental cross section and the CCBA
prediction for the 2+ transition, we investigated the dependence of the cross section on reasonablevariations of deformation and optical-model parameters.

It was found that such variations indeformation and optical-model parameters result in non-negligible changes in the shape of the

27

10'

22

Ne ( P.t)20 Ne

Ep= 39.8 MeV-EFR-CCBA---ZR-CCBA
\

\

,,
,, ,,
,
,:

\

10"

\

o·0

.

10-2

...

~

D

..§.
t>1~
"0"0

•

10"

Fig. 1.
Comparison of EFR-CCBA(solid lines) and ZR-CCBA (dashed lines)
calculations with the datal) for the•..... oeodifferential cross sections to the 0+ (g.s.),2+ 0.63 MeV), and 4+ (4.25 MeV)
states of 2oNe.

angular distribution, but some differences between the theory and experiment for the 2+ transition
still remained. The result points out that other higher-order reaction mechanisms such as
successive transfer processes not included in the CCBA calculation could account for some of theremaining discrepancies.

References
1)

D.K. Olsen, T. Udagawa, T. Tamura, and R.E. Brown: Phys. Rev. C, ~ 609 (973).

2)
3)

C.H. King, M.A.M. Shahabuddin, and B.H. Wildenthal: Nucl. Phys., A270, 399 (976).
R. de Swinarski, A.D. Baher, F.G. Resmini, G.R. Plattner, D.L. Herndrie, and J. Raynal: Phys.
Rev. Lett., 28, 1139 (1972).

28

III-1-5.

Extended Brink Model and Its Derivation from
Distorted Wave Born Approximation

A. Ichimura, M. Ichimura, and S. Yamaji

NUCLEAR REACTIONS[Cluster transfer

J

reaction , matching conditions.

The optimum particle transfer in heavy-ion reactions has been treated by Brink using aclassical model.1)
2

Ichimura et al. )The method can be extended to cluster transfer with general mass as shown byThis schematic model predicts the optimum excitation energy and spin of

the residual nucleus. However, it does not give the strength distribution of the cross section andthe validity of the model is not warranted.
In the present work we derive the extended Brink model from the formalism of DWBA
(distorted wave Born approximation) which is a completely quantum mechanical one.

It enables

us to clarify the origin of the matching conditions and to estimate the width of the distribution
as well as the optimum conditions. In the following we summarize the logic of the derivation.
It is similar to that shown by Gross,3) but he derived only the optimum conditions for light particle
transfer.
We start from the DWBA transition amplitudes for the cluster transfer reaction,(1)

where F (30! is a nonlocal form factor determined by the clustering bound-state wave functions andby the coupling interaction. First we express the distorted wave X(+) and X( - ) according to thegeometrical optics approximation (three-dimensional 'VKB approximation).

They are constructedby the set of classical trajectries with incident momenta k O! and kf3 ' respectively.

It should be

noted here that an arbitrary point is passed in general by many classical trajectries and that thewave function is a superposition of many components.

We further make an approximation ,however, to take only one component with the largest impact parameter.

Because the flux of theother components is absorbed more rapidly , this procedure is reasonable particularly when thetransition occurs near the point of closest approach for the grazing trajectory.
The absolute value I X{3 (-) * F{3O! XQ (+) I of the integrand has a maximum when the transferredcluster is placed between the other two clusters in the reaction plane.

It is the very configuration

to be expected when the transition is assumed to occur in the schematic model. l ), 2)

Then weexpand the exponent of the integrand around this configuration and approximate it by a sixdimensional complex quadratic form.
Thus the integral (1) is reduced to a product of six Gauss integrals and finally we obtain theapproximate expression for the transition probability

29

(2)

Here A~v denotes a real regular transformation and 6.P~ transferred momenta between three clusters
by the transition. The expression (2) has a maximum when
6P

~

= 0

(}1 = 1, ... , 6) ,(3)

namely when each cluster takes no recoil. The conditions (3) are nothing but the optimum
matching conditions of the extended Brink model. The width of the distribution can be also
estimated from the expression (2).

References
1)

D. M. Brink: Phys. Lett., 40B, 37 (1972).

2)
3)

M. Ichimura, E. Takada, T. Yamaya, and K. Nagatani: ibid., 101B, 31 (1981).
D.H.E. Gross: ibid., 43B, 371 (1973).

30

III -1-6.

Angular Distribution of Reaction Products
in Preequilibrium Process

M. Takahashi,* Y. Nagame, K. Sueki,* H. Nakahara, and I. Kohno

NUCLEAR REACTIONS

59Co(3 He , n); cross section , recoil range ,[ angular distribution , pre equilibrium model.

The preequilibrium process in light -particle-induced reactions has been successfully explained by the excitonmodel originally proposed by Griffin.1)

However , the model is restricted to the explanation of energy spectra andcross sections of emitted particles.

Only recently , the model has been extended to include the angular behaviorof the preequilibrium process by WeidenmUller and his collaborators?) and also by Akkermans et al. 3) The newmodel has been tested for angular distributions of neutrons emitted in such reactions as (n , n/) , (p , n) , and (0', n).
But since the number of data available is still scant , it is necessary to accumulate more data in order to check thevalidity of the model.
In this work , angular distributions of the residual nuclei produced in the 59Coe He , n ) 61 Cu reaction at theincident energies of 17.5 MeV and 30 MeV were investigated in order to study the angular behavior in preequilibrium reaction process. Excitation functions and mean recoil ranges projected onto the beam direction werealso measured to aid the understanding of preequilibrium process. A similar work was carried out by Fujiwara
and Porile 4 ) for the reaction system of 64CueHe, n)66Ga ; they varied the incident energy from 16.9 MeV to

31:9 MeV , and covered the angular range of 0° to 42°, but the detection angles were taken at only in coarse steps.
Excitation functions and recoil ranges were measured by the stacked-foil technique .
foils 4-8 mg/ cm 2 thick prepared by an eiectrodeposition method were used.

0.0025 cm thick aluminum foils of high purity (99.997 %).

Self-supporting target

The recoil catchers consisted of

The target stack was constructed by inserting 8 - 12target foils in between aluminum catcher foils as well as appropriate aluminum energy degrading foils.

The range-

Senergy relation for 3He reported by Williamson et al. ) was used to determine the bombarding energy at eachtarget position in the stack.
and 27 MeV.

Irradiations were performed at the cyclotron with the initial beam energies of 40 MeV

The beam current was "'1.2 I1A.

After the bombardment , the reaction products recoiled into the catcher foil were chemically separated andtheir activities were determined by measurement of -y-rays with a 40 cc Ge(Li) detector.

Beam

Fig. 1.

Schematic diagram of irradiation arrangement usedin the angular distribution study.
l. Target , 2. flux monitor, 3. carbon collimator, 4. aluminumcatcher foil,S. catcher foil backing, 6. Faraday cup.

* Faculty of Science, Tokyo Metropolitan University.

The -y-rays from products

31

remaining in the targe t foil could be directly measured without chemical separation. The experiments on the
angular distribution studies were carried out in a scattering chamber by using the target and the catcher foilarrangement depicted in Fig. 1. A 30 /lg/cm 2 thick 59CO target of 99.99 % was prepared by vacuum deposition
onto a 4.5 mg/cm 2 thick aluminum foil of 99.997 % purity. The catcher foil used was of the same quality as
the one used in the stacked-foil experiments. Irradiations were performed at the 3He energy of 17.5 and 30 MeV
with the beam current of 0.3 to 0.5 /lA. The beam was collimated by a 5 cm long cylindrical carbon block witha 5 mm 1> hole which was placed at 2.5 cm upstream from the target. The distance between the target and thecatcher foil was varied from 15 cm to 62 cm depending on the angular range to be measured . The angularresolution obtained with this setup was typically about lOin the angular range of 0° to ISo, and about 3° in the
ISo to 40° . The activity of 6lCu recoiled into each ring was determined by the 'Y-ray spectrometry after proper
chemical separation and purification.

co

59CO (3 He • 2p )60

..a
E

z

0
i=

u
w

1G

1

10

(a )

o CROS S SEC TI ON

6 CCU• REC OIL RANGE

cP~~~

,t u
..a

E

¢

z

i

0

0::

J: )

E

f=

trl

0

V)

If)

lfl

0 CRO SS SECTION• REeOI L RANGE

o

I

If)

1021-

I

i

V)
V)

18

o

U

0::
_ u

E 1d

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

~------,~

(Jl

::J.

W

~

1a
<t:

0::

~

--1

u

u

o

B

W

•

•

W
0::

0::

10

20

30

~e ENERGY (MeV)

Fig. 2.

40

10

3 20

30

40

He ENERGY (MeV)

10

20
3He

30

ENERGY( ~eV)40

Excitation functions and projected mean recoil ranges of residual nuclei.

(a) , (b) , and (c) show those of CHe , 2p), CHe, 2n) , and CHe , n) reactions,
respectively.
In Fig. 2 are shown the excitation functions and projected recoil ranges of residual nuclei produced by theCHe, 2p) , CHe , n), and CHe , 2n) reactions. It was found that the energy dependence of the ratio between theobserved aCHe , n) and the total reaction cross section (calculated by the optical model) could be well explainedby the hybrid model l ) if the initial exciton number of four was assumed.

The ratio of the observed projected

mean recoil ranges to those expected by the compound nucleus formation followed by evaporation are plotted inFig. 3 as a function of bombarding energy for three kinds of reaction. The energy-range conversion was performedby the prescription of Lindhard et a1. 6) The ratio for the CHe , n) reaction fall in between those for the CHe , 2n)
and CHe, 2p) reactions.

This trend is consistent with the expectation that the CHe, 2n) reaction would beCcompound-like and that the most of the He, 2p) reaction would be accounted for by the one-neutron stripping
process. The contribution from the direct reaction (two proton stripping) to the total CHe , n) reaction crosssection was estimated to be less than 10 % from the published work 7) on the CHe, n) direct reactions.
Angular distributions of the 59CoeHe , n) reaction products obtained at the energies of 17.5 MeV and 30 MeV
are given in Fig. 4. The solid lines are calculated curves with the assumption of isotropic neutron emission fromthe compound nucleus in the center of mass system , and the dashed lines are the results of the preequilibrium
calculations for n = no where no stands for the initial exciton number. The vertical'lines "excite" and "ground"show the kinematically allowed maximum laboratory angles when emitted neutron energies are assumed to be

32

o

10

30

40

I

grou nd• (3He. n)
D. (3 He . 2n)o (J He.2p )

·c

'"

><U

~ 10

D.

2

<U

lOr-

~

'-

~ 0.5

•

~

!

•

D.

D. D.

•• • • • •
D.

0
0

00

0

0

6.

•

o~

•

~

•

•

0
0

00

~.

3 He

Fig. 3.

Energy//- - - - 0 _ _ _ _ _o_ _ _ _ - / 0

6

0

0

o
40

30

20

/

~10'~oo

.~

I

10

30MeV

6

D.

o

10

20

o

o

exc iteground

,/

140

30

(MeV)

The ratios of the observed projected

Fig. 4.

Angular distributions ofmean ranges to those expected by compound

59CoeHe, n) reaction product obtained

nucleus formation followed by evaporation.

at the incident energies of 17. 5 MeV
and 30 MeV.

(Q gg + E.1 - Bn ) and (Q gg + E.),
respectively.
Iof lCU.

E.I and Bn are the incident energy and the neutron binding energy

According to Akkermans et a1.,3) the angular distribution of emitted neutrons from the n = no state in

the center of mass system can be expressed by
d 0/ d n ex: 1/ 4 7l' { Po ( cos (j ) + 2 P 1 ( c os (j ) + 5/ 4 P 2 ( c os (j ) }where Picos 8) is the Legendre function of the f th order.

,

The observed differential cross sections in larger angles

that contribute to most of the total cross section are, however, less than those calculated.

This discrepancy

indicates that neutron emissions in the eHe, n) reaction are more forward peaking in the center of mass systemthan expected from the preequilibrium model proposed by Akkermans et a1. 3)

References

1)

J.J. Griffin: Phys. Lett., 24B, 5 (1967).

2)

G. Mantzouranis , D. Agassi, and H.A. Weidenmiiller: ibid., 57B, 220 (1975).

3)

J.M. Akkermans and H. Gruppelaar: Phys. Rev. , C 22 , 73 (1980).

4)I. Fujiwara and N.T. Porile: Phys. Rev., 173, 1055 (1968).

5)

C.M. Williamson, J.P. Boujot, and J. Picard: Saclay Report CER-R, 3042 (1966).

6)

J. Lindhard, M. Scharff, and H.E. Schiott: Mat. Fys. Medd. Dan. Vid. Selk., ~ No. 14 (1963).

7)

M.B. Greenfield and C.R. Bingham: Phys. Rev. C, §.' 1756 (1972).

33

III-1-7.

Strongly Damped Components in the Reaction of

2°Ne + 50Cr and 2°Ne + 54Cr Systems

Y. Nagame, 1. Kohno, H. Nakahara, H. Kudo*,
K. Sueki,* M. Takahashi,* and M. Yanokura

NUCLEAR REACTIONS

20Ne + sOCr, 20Ne + 54Cr, strongly damped

1

component, bombarding energy dependence, target isotope dependence ,[ rotating liquid drop model, diffusion model.

The reactions of 20Ne + sOCr and 20Ne + S4Cr systems were investigated.

The strongly damped

components, especially, symmetric mass fragmentation products were analyzed in terms of the
diffusion model!) as well as the rotating liquid drop model 2) for fission . The interpretation was
performed from the following two systematic features: i) bombarding energy dependence (angularmomentum effect); ii) target isotope dependence.

The systems studied in this work, the conditions

for compound nucleus formation and its decay by fission are summerized in Table l.
Table 1.

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

Reaction

Compoundnucletls

Fissility(Z2 fA)

EL
(MeV)

eN a)
Ex
(MeV)

16.5

146

16.5

I
a)
b)
c)

.eerit b) .eBf=Bn c) Bf at Pcrit
(h)

(h)

(MeV)

108.6

53

44

5.0

120

90.0

47

44

10.3

16.5

93

70.7

40

44

19.0

15.6

146

114.8

55

50

7.0

compound nucleus excitation energies.
Ref. 3.
t'Bf= Bn characterises the f value at which the fission barrier Bf coincides with neutron binding energy.

The details of the experimental procedure have already been reported in a previous report. 4)
The trends of the energy spectra and angular distributions obtained in the 120 MeV 20Ne +50Cr and 146 MeV 20Ne + 54Cr systems are similar to those observed for the 146 MeV 20Ne + sOCr
reaction. 4)
The charge distributions of the target isotope and bombarding energy dependence are shownin Figs. 1 and 2, respectively.
As shown in Fig. 1, there are difference in the cross sections of the strongly damped products
between the 146 MeV 20Ne + 50Cr reaction and 146 MeV 20Ne + 54Cr reaction. The yields for* Faculty of Science, Tokyo Metropolitan University.

340146 MeV 2°Ne + sOCr
• 120 MeV 2° Ne + sOCr

at eem = 40

0

1./.

?

•

z

z

Fig. 1.

Fig. 2.

Charge distributions at tworeaction system.

Charge distributions at two

different bombarding energies at

These cross sections

eem = 40° .

are integrated over an angular range

The solid lines show

calculated charge distribution witht1/2 = 10 X 10 - 22 sec. The

from 30° to 60° in the center-ofmass system.

calculations are normalized to thedata at Z = 15.
the 20Ne + 50Cr system were found to be about twice to three times larger than for the 20Ne +54Cr system, while the difference was not observed in the products lighter than the projectile.
This isotopic effect in the strongly damped components is similar to that observed between thesystem 14N + 58Ni and 14N + 64Ni .5) As shown in Fig. 2, the difference of the yield in thestrongly damped components were observed even between the reactions 120 MeV 20Ne + 50Cr and
146 MeV 20Ne + 50Cr.

given in Fig. 3.

The excitation function of the symmetric fission-like products (Z = 17) is

These results of the isotopic and bombarding energy dependence can bequalitatively explained by the fission barrier height predicted by rotating liquid drop model 2) asshown in Table I.
If it is supposed that the transfer of charge Z or mass A conforms to the diffusion
phenomena,1) the total charge distribution is given by the integration over f-value from criticalangular momentum f en·t to maximum angular momentum f max as follows;6)
d (j
-dZ

1

2 7l'
k

= -2

J

f rna x

.

fent

I? P

{

Z1

'tj nt (
'

f )

}

d

e

with asymptotic wave number k and the e-dependent interaction time 7 int (I?).

(1)

The probability

distribution P 1Zl ' 7 int (/:') f is given by a gaussian function,6)

where Zp is the projectile charge, vz and Dz are drift velocity and diffusion constant, respectively.

35

The interaction time T int(£) can be generally obtained from angle of observation using an angularvelocity. Supposing that the composite system rotates , it is possible to calculate the angularvelocity of the system by taking a rigid-body sticking model. An additional parameter which isthe probability of survival of a composite system after time Tint (£) would be given by
exp(-XT int (£)) ,7) where X ( = 0.693/t 1 / 2 ) is the decomposition probability constant and tl/2 is thehalf-life time of the composite system. Thus the contribution of projectile-like fragments to theprobability of obtaining a charge Z1 at an angle e can be given by the following equation: 7)(3)

where if egr < eTint (.e )3 = ~ { 2 7r - ( e - egr) } , ........... .

w being the P-dependent angular velocity of the composite system. It has been assumed that thestrongly damped components are associated with negative scattering angles. One charge can havecontributions from projectile-like fragments, and also it can have contributions from target-likefragments.

The total probability of observing a charge Z1 at an angle e will be given by(4)

146 MeV 2° Ne + 50 Cr--- 146 MeV 2° Ne + 54C r

~

"\ \

"' ,
1

da
aZ = 17= 27r oSln8
dQ d8

\

~~-

- -~-"""""-""-----,....,z
Fig. 3. Exciation function forthe symmetric fission-likeproducts (Z = 17). The curveshow calculated values. The
calculations are normalized to thedata at Ecm = 104 MeV.

Fig. 4.
Liquid drop potential energy
curves of two touching spheres relative
to the rotating composite system as afunction of mass asymmetry for different
orbital angular momentum P. The arrows
indicate the injection points.

36

The differential cross section will be given byd 2 (j'27l--=-dedZ 1

k2

f

£ max

e)d£

£P ( ZI£ cr i t(5)'

Transport coefficients vz and D z used in this calculation were obtained from theoreticalexpressions. 1 )Figures 2 and 3 show that the bombarding energy dependence reproduce the relative
enhancement of symmetric fragmentation at high energy .

This is due to the strong drift towards

symmetry for high angular momenta caused by the deep minimum at symmetry in the potential
energy curves as shown in Fig. 4.

The charge distributions calculated with Eqn. (5) at e = 40°

and t 1/2 = 10 - 21 sec indicate that the isotopic dependence in the strongly damped components
between 20Ne + 50Cr and 20Ne + 54Cr is not observed as shown in Fig. 5.

Therefore, this isotopic

effect in the strongly damped components, especially symmetric mass fragmentation products, isconsidered to reflect the contribution of the fissility parameter (Z2 / A), i.e., fission barrier height.

>

Q)

L

l = 40--------

----

1= 20

-

2

°Ne+ ooCr
54Cr~'-;. 1--~--~---::::-'-:----='0.5 Fig. 5. Calculated charge distributions
for two reaction systems.

References
1)

W. Norenberg: J. Phys. C5, 37, 141 (1976).

2)

S. Cohen, F. Plasil, and W.J. Swiatecki: Ann. Phys., 82, 557 (1974).

3)

R. Bass: Nucl. Phys. , A231, 45 (1974).

4)

Y. Nagame, I. Kohno, M. Yanokura, H. Kudo, and H. Nakahara: IPCR Cyclotron Progr.
Rep., 14 , 34 (1980).

5)

M. Yanokura, H. Nakahara, and I. Kohno: J. Phys. Soc. Japan, 2Q, 369 (1981).

6)

G. Wolshin and W. Norenberg: Z. Phys., A284, 209 (1978).

7)

S. Agarwal: ibid ., A297, 41 (1980).

37

III - 1 -8.

Incident Enerqy Dependence of Heavy-Residue Products

K. Sueki, * Y. Nagame, M. Takahashi, * H. Nakahara, and I. Kohno

62Ni(14N , X); measured cross section, ]NUCLEAR REACTION[ its energy dependence.

The aim of the present work is to study the incident energy dependence of yields of heavy-residue products
The reaction system chosen was ct 4 N + 62Ni) andthe 14N energy incident on each enriched self-supporting 62Ni target foil (1 - 2 mg/cm 2 ) was varied by the stacked-

in heavy-ion induced reactions of a relatively light mass system.
foil method.

Aluminum catcher foils (5.53 mg/cm 2 ) of 99.997 % purity were inserted in between target foils inorder to collect the recoiling products.
intensity of 0.5 J,lA.

Irradiations were performed using the cyclotron for 6 h with the beam

The energy range covered was from 85 to 120 MeV.

Three kinds of heavy-residue products were investigated: (1) those with masses close to the compound mass,(2) cobalt isotopes which could be considered as pxn transfer products from the target , and (3) scandium isotopes
whose atomic number is smaller than that of the target by seven units.

The yields of the first kind of produ cts

could be determined by directly measuring 'Y-rays with a Ge(Li) detector whereas those of the other kinds could bedetermined only after proper chemical separations.
10 2 r - - r - - - - - - , - - - - - , - - - - - - ,

I

t-

10

1

1

-

(a)

-

I

I

I

I

I

I

44mSc -

(b)

-

.Q

E

o 73 Se•71 As

t:. 70 As
•

o

67 Ga

o 66 Ga

z

~

t-

U
UJ

1Il

iji 10- 1 _

5

t-

f-

1 -----',------'
10 1 L-~t___~I ~IL_~t___L_t~t__~,----_.1.....-

10- 3,---...1..80

Fig. 1.

100
E (MeV)

120

Excitation functions offusion residue products.

80

100
120
E ( MeV)

80

100

120

E ( MeV )Fig. 2.

Incident energy dependence of cross section: (a) Cobalt

isotopes;(b) Scandium isotopes.

* Faculty of Science, Tokyo Metropolitan University.

38

Theoretical understanding of the data is still in progress, and only important features of the experimental
data observed are presented in this report.
Excitation functions obtained for the first kind of products are shown in Fig. 1.
figure are simply to guide the eye.

The lines drawn in the

The yield of 73Se which was produced either by three neutron emission

followed by 0+ decay or by one proton and two neutron emission from the fused nucleus could not be fitted by
the evaporation calculation.

The mean projected range of 73Se in nickel metal observed by the conventional

thick-target thick-catcher foil method 1) also turned out to be only a half of what was expected for full-momentum
transfer reactions.

The preequilibrium process may, therefore, be effective for the formation of 73Se.

Excitation functions of cobalt isotopes and scandium isotopes are shown in Fig. 2 (a) and (b), respectively.
The cross sections are not corrected for the contribution from the parent nuclides in /3-decay chains. However ,cobalt and scandium isotopes 61Co, 6OCo, 58CO, and 44S C, 46Sc , 47SC, 48Sc are shielded nuclides in /3+ -decay chains andthey can be considered free from the effect of parents.

Although yields of the parent nuclides of 57CO and 56CO,

namely, 57Ni (36.1 h) and 56Ni (6.10 d) were tried to obtain , they were found below the detection limit.
Consequently , contributions from parent nuclides can also be considered negligibly small even for 57CO and 56CO.
From the figures it is found that the energy dependence of yields of cobalt isotopes is similar to that of scandium
isotopes although the latter seems to be somewhat steeper.
In Fig. 3 are shown the ratios of the activity of the respective isotope recoiled into the forward catcher foil,
C, to that found remaining in the target foil, T.

They are re lated to the mean projected ranges, and therefore, tothe amounts of linear momenta transferred to the product nuclides.

The figure shows that the amount of linear

momentum transfer becomes larger as the number of neutrons stripped off from the target nuclide becomeslarger.

The ratio for 55Co, however, does not follow this trend.

The isotopic yield distributions of cobalt isotopes observed at three different incident energies are shown in
Fig. 4.

They can be well fitted by Gaussian curves.

The charge density of each isotope is shown in terms of

Nil on the horizontal scale given at the top of the figure.

Also indicated by arrows are the Ni l values of thetarget nuclide (TN) and of the compound nucleus (CN).

The most probable Nil value of the present reaction
N/Z

2.0

•
•
10

E=120MeV

t

;'oL
1.0

•

•
0

r

0
E=100MeV

0

...

J

E = 85MeV

55

Fig. 3.

59
60
57
58
56
A (MASS NUMBER) Z = 27

CIT ratios for cobalt isotopes.

55

56

57

58

59

60

61

A

Fig. 4.

Isotopic yield distribution ofcobalt isotopes.

39

10

2

• 120MeV

•
10

0

...

1

100MeV
85MeV

T= 2.50MpV

0N/Z
10°r--,I._I__~-,1.~2__~-,1.r3~,
eN 'TN'
120MeV_

!

!

z

~
IU

W

If)

~ 10- 1ex:ulif3~_~I~I___L-I~I__~1~~

44

45

46

47

o

48

Fig. 5.

-10
Qgg+~EcA

Isotopic yield distribution

Fig. 6.

-20
(MeV)

-30

The Qgg dependence of cabalt isotopes.

~Ec indicates the difference in CouLombof scandium isotopes at 120 MeV.

interaction energy between the entrance andexit channels.

system for cobalt products seems to shift from the TN to CN as the incident 14N energy is increased.
were made in Fig. 5 for scandium isotopes.
value.

Similar plots

The most-probable N/Z value is found a little smaller than the CN

This fact may suggest that a larger number of neutrons are emitted in the reaction process producing

scandium isotopes.

However, it is to be noted that the width of the scandium distribution at 120 MeV is notvery different from that of the cobalt distribution observed at the same energy as shown in Fig. 4.
In Fig. 6 are plotted the cross section for cobalt isotopes as a function of the (Q gg +.6.E)
value.
c
6OCo seem to show the so-called Qgg dependence fairly well.

All but

The temperature deduced from the slope of thelines 2 ) is 2.5 MeV, and it is rather independent of the incident 14N energy within the range investigated in thepresent work.
Similar studies are in progress for the nickel targets of different mass numbers.

References

1)

Y. Nagame, M. Watanabe, H. Kudo, H. Nakahara, I. Kohno, and M. Yanokura: IPCR Cyclotron Progr. Rep.,

14,37 (1980).
2)

V.V. Volkov: Phys. Rep., 44, 93 (1978).

40

III - 1-9.

light- Particle Emissions in the

93 Nb

+

14N

Reactionin the Region of ~ 7 to ~ 15 MeV / A

M. Ishihara , T. Fukuda ,* M. Tanaka,** H. Ogata,***I. Miura,*** T. Shimoda ,* and K. Katori*

NUCLEAR REACTIONS

93Nbct4N , X) with X = p, d , t , Q ,J[ E = 132 , 160 , 210 MeV; measured aCE , fJ).

The strong emission of fast - light particles is one of characteristic aspects of heavy-ion
reactions in a broad region of the projectile energy.
account for these emissions.

Several mechanisms have been proposed toApparently , the phenomenon bears different features as the incident

energy varies from low to high energies.

In the low-energy region of rv5 MeV/nucleon, the energy

spectrum shows a Maxwellian-line shape , which may favour treatments in terms of "hot-spot" modeland "exciton" models.

On the other hand, in the high-energy region of some 100 MeV/nucleon,

the aspect of projectile fragmentation dominates.

In the intermediate region, the competition

among such different mechanisms is likely.
The present work is aimed at investigation of energy dependence of the light-particle emission
in the 93Nb + 14N reaction in the energy range of rv7 to rv 15 MeV / nucleon.

The 14N beam of

132 , 160 , and 210 MeV from the RCNP cyclotron (Research Center for Nuclear Physics at Osaka)
was used to irradiate a metalic target of 93Nb.

Energy spectra and angular distributions of light-

charged particles, i.e., p, d, t, and ~ were measured using telescopes of Si-detectors and thoseincorporating intrinsic Ge detectors.
Figure ] shows some energy spectra of ~ particles taken at different incident energies.

The

spectra shown are those -obtained after subtracting the equilibrium components whose intensities
and spectral shapes are estimated from the data at backward angles.

The spectra at 115 MeV arechara ~ terized by their shapes, which may be fitted

by Maxwellian shapes. At higher incident
energies, the spectral shapes no longer exhibit such a monotonic structure; typically , for the 210
MeV data at forward angles, the energy spectra clearly show an extra enhancement in the higher
energy region and particularly in the energy region corresponding to the incident velocity of the
projectile.

Recently an alpha-particle-emission mechanism 1) associated with the projectile breakup

was proposed.

The enhancement at the higher energy region is suggestive of such a mechanism.

The angular distributions of p , d , t, and ~ taken at 132 MeV are compared in Fig. 2.
equilibrium components are again subtracted.

The slope of the distribution is rather similar

among p , d, t, while that of a is considerably steeper.

The significant deviation observed for thealpha particles may characterize a particular feature of the alpha-particle emission.
A detailed description of data and comparison of the results with various models are inpreparation.
* Department of Physics, Osaka University.
** Kobe Tokiwa Junior College.
** * Research Center for Nuclear Phy sics, Osaka University.

The

41

.-.. 10 4
>Q)

L

~ 10

3

.........
..0

:::t

'-;; 10 2
~

"'"

q

~ 10 1~

Fig. 1.

80

100

0

o

20
40
Ea ( MeV)

20

40

60

60

o

20

40

60

Examples of alpha-particle energy spectra for EcI 4 N) = 210,

160, and 13 2 MeV shown , respectively , in the top, middle and bottomrows.

The vertical axices represent the differential cross section,d 2 a/dndEQ, in unit of ,ub/sroMeV, and the horizontal axies thealpha-particle energy EQ in unit of Me V.

42

Fig. 2.
Angular distributions of p, d, t, and C\'
in the 93Nb + 14N reaction at 132 MeV.

Reference

1)

T. Udagawa and T. Tamura: Phys. Rev. Lett., 45, 1311 (1980).

43

111-1-10.

Alpha Particle vs. Eiectile Correlationsin the93

Nb + 14N Reaction at 208 MeV

M. Ishihara, T. Fukuda,* M. Tanaka,** H. Ogata,***I. Miura,*** T. Shimoda,* and K. Katori*

NUCLEAR REACTION

93Nct4N, aX) with X = Li - 0, E = 208 MeV; ][ measured correlations between a and X.

The present note is to report on the correlation between alpha particles and ejectiles measured
in the heavy ion reaction 93Nb + 208 MeV 14N. A large number of experiments on suchcorrelations have been reported for various reactions, being followed by suggestions of different
mechanisms to account for the phenomena. The accumulated data now indicate two types ofmechanisms to be significant for the correlation observed. The first is a sequential emission ofalpha particles from excited ejectiles produced in the primary heavy ion reaction. 1) The second
bears a feature of direct ternary process and is argued 2 ) to have characteristic behaviour of crosssections as described by the factorized form

where subscripts I and 2 refer to ejectile and alpha particle, respectively. The important property
involved in this formula is that the energy and angular dependence of each of the coincident
particles are identical with those of singles. This particular property involved a conjecture that thedirect-like mechanism may consist of a two-step process, i.e., the projectile breakup followed bydeep-inelastic-type reaction.
The primary aim of the present work is to obtain further information on the direct-likeprocess. In the experiments so far performed, the counter for ejectiles was usually placed atforward angles. This resulted in significant contamination of the ejectile-decay component in theobserved spectra so that the validity of (1) is hard to be tested. In the present measurement, thecorrelation has been observed for three ejectile angles, 22°, 50°, and 80°. For the data of the
backward angles, 50° and 80°, the kinematic conditions allowed to isolate the two components
fairly well. Moreover, the present data provides extended information on the direct-like process
over a wider angular range.
The experiment was performed using 14N ions from the RCNP cyclotron at Osaka University.
The alpha particles and ejectiles were detected in coincidence using conventional Si-detector
telescopes. The energy and angular correlations were recorded. A detailed report on theexperiment will be published elsewhere. Here we only describe some of the characteristic featuresof the experimental results.

* Department of Physics, Osaka University.
** Kobe Tokiwa Junior College.
*** Research Center for Nuclear Physics, Osaka University.

44

(a )

(e )

(b)
1

1

1

I

I

I

I

I

1

-

-

-

-

-

o

o
-

-

10-1 -

~

Bl

+

1

- 80

0

1

- 40

1
0

1

1

1

1

-

-

10-2 -

0 Li

-

l\

Be

-

oB
-C
oN

I--

1

1

- 80

o

0

0

-

o

o

-

0 Li

-

Be
B

-

l\

I-- 0

- C

oN
1

_ 40

1
0

I

+ 40

0

+80

0

I

I

- 40

I
0

0

0

+40

0

+80

0

B2

Fig. 1.
Energy integrated angular distributions of alpha particles in coincidence with various
ejectiles for ejectile angles of 22° (a), 50° (b) and 80° (c). The solid line indicates the slopeof the singles angular distribution. Note that contributions from sequential ejectile breakup
are significant in the angular range of 82 > 0 for (a) , at 82 = 35° for (b), and at 82 = 45°
for (c).

Figure 1 compares the energy integrated angular distributions of alpha particles (angle 82 )in coincidence with ejectiles which were detected at 8 1 = 22°, 50°, and 80°. According to therelation (1), the same shapes of angular distributions are expected. This feature is apparently
missing in the observed distributions, which show gradual flattening of the slope as the ejectile
angle becomes more backward. In spite of such difference, the angular distributions have acommon feature. The peak angle is close to 0°, i.e., the direction of the beam. This aspect,which is also implied by Eqn. (1), is suggestive of a reaction mechanism, in which alpha particles
are emitted prior to the ejectiles.
The coincidence energy spectra of alpha particles and ejectiles were also compared with Eqn.
(1). For the result for 82 = 22°, alpha-particle spectra are similar in shape with singles inaccordance with Eqn. (1). For the more backward angles of 8 1 , however, the coincidence alphaparticle spectra become more deviated from singles spectra, being attenuated in the higher energy
region. Apparently higher-energy alpha particles contribute more to events involving forward
angle emission of ejectiles. The different behaviours of low- and high-energy alpha particles aresuggestive of the coexistance of varied reaction mechanisms.

References
1)

M. Bini, C.K. Gelbke, D.K. Scott, T.J.M. Symons, P. Doll , D.L. Hendrie , J.L. Lavilla,
J. Mahoney, M.C. Mermaz , C. Olmer, K. Van Bibber, and H.H. Wieman: Phys. Rev., C 22,
1945 (1980).

2)

R.K. Bhowmik, E.C. Pollaco, N.E. Sanderson, J.B.A. England, and G.C. Morrison: Phys.
Lett., 80B, 41 (1978); Phys. Rev. Lett. , 43, 619 (1979J:

45

III -1-11.

Proiectile Dependence of Fast Light-Particle Emission
in Heavy-Ion Reaction

K. Ieki, M. Ishihara, T. Inamura, and S. Kohmoto

NUCLEAR REACTIONS

93Nb(X, a), X = 14N, 16 0, 19p, and 2ONe,1

E = 7.3 MeV/amu; measured energy spectra and angular distribution;[

compound component subtraction, projectile dependence.

This work is concerned with light-particle emission in light heavy-ion reactions. Suchemission is characterized by following features: (a) high energy component is enhanced in energy
spectra in comparison with evaporation spectra; (b) differential cross section is forward peaked.
These features suggest that fast light-particles are emitted in an early stage of reaction andseveral models (hot spot, massive transfer, exciton, etc.) have been propose-a-: - To study thisphenomenon more systematically, we have measured differential cross sections and energy spectraof light-particle emissions for several different projectiles.
Various heavy ion beams (14N 106 MeV, 16 0 120 MeV, 19F 136 MeV, 20Ne 139 MeV) fromthe cyclotron were used to bombard 93Nb foil of 3.4 mg/cm 2. We chose as projectile energy
about 7.3 MeV per nucleon for all ions. We measured angular distributions and energy spectra ofemitted light particles (p, d, t, a, etc.) with a counter telescope consisting of 30 11m and 5 mm Si
detectors. We here report the results for a particles.
Angular distributions are shown in Fig. 1. For every projectile, the angular distribution is
forward peaked. At backward angles, energy spectra are well reproduced with Maxwellian shape.
Nuclear temperatures extracted from energy spectra are nearly constant for e > 1200 , so weX

14

N 106MeV

16•
0 120MeV+ 19F 136MeV

( a)

x

--;;--1'E(/)

v zONe140MeV

\

~

\

(b)

\\:
~.
v

'.

o '-----.-J
3o~---l60--9-L.O-----'-------1...L50--1. .80.J

Bc.m .

( deg )

Fig. 1.

Angular distribution of emitted
a-particles.
(a) measured distribution.
(b) compound component subtracted
distribution.

46

assumed that particles emitted backward are evaporated from compound nucleus.

Particles emitted

forward originate both from compound process and from non-compound process.

The non-compound component of present interest was deduced by subtracting the compound component;
the subtraction was made by assuming 90° symmetry of the compound cross sections.

Figure 1(b)shows angular distributions of non-compound component. They all look very similar both inshape and magnitude. Initially we anticipated that difference of transfered mass or difference ofgrazing angular momentum would reflect on the cross section, but such differences are not so
distinct.
Figure 2 shows typical energy spectra for non-compound component. Energy spectra exhibit
some difference in width. In order to display the difference more quantitatively, we fitted energy
spectra to Maxwellian shape. Though high energy part (E ~ 35 MeV) deviates, main part of thespectrum is well characterized by the Maxwellian shape. The fitted values of nuclear temperature (T)1 0 4~------------------------~( 14

N, 0 ) 106M eV

10Fig. 2.

o

10

20

30

40

Ec . m . ( MeV)

60

70~-particle energy spectra at 8 c . m . = 35°

in log scale.

Line is fitted curve to

Maxwellian shape.

are shown in Fig. 3(a). The projectile dependence of T is rather smooth and T is larger for smaller
mass of projectile. Note that the total energy brought on the target is smaller for smaller mass ofprojectile so that lower T is expected for the case of an equilibrated process. It is also noted thatthe variation of T with projectile does not show a particular dependence on the projectile structurewith respect to whether or not the projectile is a 4N nucleus.
With temperature T, one may derive effective level density parameter a by
a = U/T 2 ,where U is total excitation energy. The parameter a may represent the effective number of degrees
of freedom involved in the pre equilibrium excitation. To see the relation of a to projectile mass
number A, we plot the values of a/ A in Fig. 3(b).
larger and the gradient is steeper.
projectile.

For heavier projectile, the ratio a/ A is slightly

This fact may imply that relaxation occurs faster for heavier

47

I

I

I

-

81-

14 N + 93 Nb 1 06Me V• 16 0 + 93 Nb 120Me V

X

7
41-

+ 19 F + 93 Nb 136MeV-'V

2° Ne+ 93 Nb 139MeV

6
3r-

5
>

Q)

2:

4

h

2 r-

3
2111-

11i
l
I
OL----3Lo--~60----9~0~--1~20~-15~0~-1~80

Bc.m.

Fig. 3 (a).
nucleus.

o(degJ

Nuclear temperature of residual

I

I

30

60
Bc .rn.

Fig. 3 (b).

90

( de g)Effective level density parametera divided by projectile mass number A.

48

III-1-12.

Polarization of Continuous Protons Emitted at

40° in the93

Nb+ 14N Reaction

T. Sugitate,* T. Nomura, H. Utsunomiya,
M. Ishihara, K. Ieki, and S. Kohmoto

NUCLEAR REACTION 93Nbct4N , p), E = 95 MeV; measured spin polarization[ ( e = 20° ). double scattering method.

J

The polarization measurement for protons emitted at 40° in the 93Nb + 14N reaction at 95
Me V has been carried out by the double scattering method.
as that described previously. 1)

The experimental method is the same

The result is given in Fig. 1.

The measured value of polarizationis small for low energy protons but increases with the increasing proton energy, reaching about

20 % at E C. In . ~ 20 Me V. This tendency is similar to the case. observed at 20° in the same
reaction reported in Ref. I and is considered to be due to the fact that the proportion of apreequilibrium (PE) component in a continuous energy spectrum at 40° increases with theincreasing energy . I)

The upper part of Fig. 2 shows energy spectra of protons emitted at elab

40° and 134°, which roughly correspond to those at eC.In. = 43° and 137°, respectively.
spectrum at

eC.In .

Since the= 137° approximately represents an equilibrium (EQ) component at eC.In. = 43 °as explained in Ref. 1, the difference between the two spectra in Fig. 2 gives a PE component at

e

C.In .

= 43°.

The lower part of Fig. 2 shows this proportion as a function of energy .

If weassume that the EQ component is completely unpolarized , and that the polarization (P) of the PE
component is independent of energy, the experimental polarization has been well fitted by using
the proportion of the PE component mentioned above.

The result is shown by a solid curve in

Fig. 2, from which we obtain P = 38 ± 10 %.

30
B lab
~

= 40

.~F++

0

20

c
0
CO
N
CO

0

n...

10
0

I

10
-10

5

I

I

I

10

I

l ab

I

I

I

( MeV) 30

15
J:'cm

Fig. 1.

I

20 E

20

( MeV)The measured (circles) and estimated (solid curve)

values of proton polarization observed at 40°.

* Present address: Department of Physics, Hiroshima University.

49

5

:;
z:
Q)

....:

en

..0

------Ee:~' = 137"

ltl

(j

q

(j

Nt::>
------(jFig. 2.
I~

I

I

spectra of protons at Blab = 40° andI08:~'=43°

50-

c:
0

0

0..

0

D-

O

5

Upper: Experimental energy-~

134 , which roughly correspond to
those at Be .m . = 43° and 137°, respectively .
The difference of the two spectra is also
given .

I

I

I

10

15

20

Ecm ( MeV)

Lower: The proportion of thepreequilibrium component deduced as
explained in the text.

Reference
1)

T . Sugitate, T. Nomura , M. Ishihara, Y . Gono , H. Utsunomiya, K. Ieki, and S. Kohmoto:

IPCR Cyclotron Progr. Rep. , 14, 28 (1980) .

50

III -1-13.

light-Particle Emission Following 7li-lnduced Reactions

H. Utsunomiya, S. Kubono, * M. Tanaka, *K. Morita,* M. Sugitani,* and T. Nomura

N~CLEAR REACT~ON 93NbC~i, x), 159T bC Li, x), 232ThCLi, X)']E - 49,77 MeV, x - p, d, t, a, f, measured aCE, 8), angular[correlations.

The light-particle emission has been studied in 7Li-induced reactions on 93Nb, 159Tb, and232Th targets.

The experiment has been carried out at beam energy of 49 Me V at Riken and of

77 Me V at Institute for Nuclear Study.

The following measurements have been done: 1) energy

and angular distributions of protons, deuterons, tritons and 0' particles measured between 20° and160°; 2) angular correlations of two light particles emitted at forward angles (mainly between 20°
and 50°); 3) angular correlations between light particles and fission fragments in order to study
angular-momentum transfer and alignment in the case of 232Th target.
The analysis of the experimental results is now in progress.

* Institute for Nuclear Study , University of Tokyo.

51

III - 1 - 14.

Influence of Chemical Environment on Outer-Shell
Internal Conversion in 119Sn

H. Muramatsu, T. Miura, H. Nakahara, M. Fujioka,
E. Tanaka, * and A. Hashizume

119Sb ; measured E ce , Ice ; dedu ced Chemical]
RADIOACTIVITY
effect, O/N l ' 5s electron density , CaSn03 , white tin.

[ Iron free magnetic spectrometer.

Enriched targets.

In a number of experiments 1 ) chemical states have been shown to affect the rate of radioactive decay .

Theseeffects are related with the sum of electron densities of several electron orbitals near the nucleus, that is , with theso-called electron contact densities.

However, quantitative analysis of these results is almost impossible because of

the lack of knowledge of the effects of chemical binding on the related electron wave functions. On the other hand,observations of the internal conversion probabilities of the outermost shell electrons give more direct informationon the effects of chemical binding on each individual electron wave function.

Chemical effects on internalconversions of the outermost shell electrons was investigated by several groups in the past. 2 )For experiments of this type with a high resolution beta-ray spectrometer, it is necessary that the transitionenergy is less than about 50 keVin order for the conversion line due to the electrons in the outermost shell to be
separated from that due to the electrons in the next-inner shell.

This requirement comes from the fact that thebest momentum resolution of the spectrometer is about 0.05 % in this energy region and the energy difference
between the conversion line of the outermost shell electrons and that of the next-inner shell electrons is 137 eV.
It is also preferable that the transition multipolarity is that of a magnetic dipole (M 1) since such conversion can beinterpreted simply in terms of the s-orbital electron density.

Therefore , we chose the 23.87 keY Ml transitionof 119Sn that follows decay of 119Sb (T 1/2 = 38.1 h) in our investigations.

In this case , the energy of theconversion electron is so low and energy losses of such electrons are considerably large that high resolution
measurements of the conversion electron spectra become extremely difficult , and the most essential problem is how
to prepare a source sufficiently thin, e.g. 10 J1.g/cm 2 .
Internal conversion sources with different chemical environments , namely, white tin and CaSn0 3 , wereprepared by the implantation of 119Sb using the electromagnetic isotope separator at Tohoku University. The
119Sb was obtained by the milking method from 119mTe produced by proton irradiation of the natural antimony at
AYF cyclotron of Tohoku University.

Implantation of the radioactive 119Sb was carried out at the terminal

potential of 20 kV at room temperature. The dose rate was ~ 10 7 atoms/cm 2 for the mass number 119. From
the radioactivity of the implanted sample, the number of implanted 119Sb atoms was determined to be :::; 10 12
atoms/cm 2 .

In order to identify the final chemical state of the samples , emission Mossbauer spectra were measured

with a CaSn0 3 absorber at 77 and 150 K.
Measurement of conversion electron spectra was made with a 50 cm, double focusing, iron-free beta-ray
spectrometer at the Riken. A resolution of 0.14 % in momentum (full width at half maximum measured at LI
line of the 23.87 keY transition) was achieved with a 1 mm X 20 mm source and 1 mm X 20 mm final detector
aperture.

The detector was a gas-flow proportional counter with a thin polypropylene window ('" 100 J1.g/cm 2 ).

All the conversion lines of the 23.87 keY transition were measured.

In Fig. 1 there are shown the conversion

electron spectra in the region of Nand 0 lines from sources of white tin and CaSn0 3 .
normalized to equal N r line intensity and K-LM Auger lines of tin are also shown.
the energy difference of 137 e V could be clearly resolved from each other.

The spectra have been

The NI line and 0 lines with

The relative intensities of the Nando lines were evaluated using the computer code, ACSEMp3) whose function essentially a least-squares analysis* Faculty of Science, Tohoku University.

52

4

10

K-LIMI
~

i

~10
z
=>
>

0

I

ex:
<{
ex:

~

r

N

\

~

~~
':~~O

CD
0::

<{

z10
=>

0

u

1I

J ~mJ

-- 3

2

MIV,V

0

Nr

(/')
~

~~
I

t ••••

~

~~

l '\

o!Oo~~,e.•

~o

1'.-]

1

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

23000

22000

POTENTIOMETER SETTING
Fig. 1.

Conversion electron spectra from two different 119Sb

sources. The curves have been normalized to equal N 1 line
intensity.
•

source No.8 (CaSn0 3 )o source No.9 (white tin)using empirical profiles.

The K-LM Auger spectra , on which the 23.87 keY Nand 0 lines are super-imposed in

the energy region 23.7 to 24.0 keY, were independently observed by using a radioactive tin isotope, f17mSn andthey were subtracted from the conversion electron spectra as a background in the spectral analysis of conversion
lines.
Results of the analyses of two different sources are listed in Table 1.

For the source No.8, the Mbssbauer

spectrum indicated that only 47 % of the 119Sb doped in the material was in the form of CaSn0 3 .

Therefore ,the O/N r intensity ratio was corrected on the assumption that the rest, which had an isomer shift similar to that
Table 1.

Relative intensity ratios (O/Nr) from internal conversionof the 23.87 keY Ml transition in 119Sn.
Source0.086 ± 0.015~ 0.066 ± 0.013

No.9(white tin)0.12

± 0.015

53

of white tin, was of the chemical composition of the source No.9.

If the effects of the change in the 5s electron

density on the inner s-electron densities are small , one can deduce the 5s electron density at the nucleus from theobserved O/NI ratios by using the formulawhere \ l/J (0)5 5 \2X is the 5s electron density at the nucleus for the chemical medium x and \ l/J (0)4 5 \2 is the 4selectron density of the tin atom. We adopted a value of 719 a.u. for the \l/J (0)45 \2 reported by Band et a1. 4)
who carried out relativistic Dirac-Fock calculations for the tin atom and ions.

The difference in the 5s electron

density between white tin and CaSn03 is then evaluated as
Ll 1 ¢ ( 0 ) 55 12 = 1 ¢ ( 0 ) 55 1

~asno 3 - I¢ ( 0 ) 5 s ;n1

= - 38 a . u.
This result shows that the presence of more electrophilic oxgen atoms around the tin atoms causes the reductionof the valence s-electrons in the tin atom.

The change of the lifetime of the 23.87 keV level is also calculated

to be about 0 .12 %, that is , the lifetime of the 23.87 keV state of 119Sn in CaSn03 is expected to be about 0.1 2 %longer than that of white tin.

References1)
2)

See , for example , R .F. Leininger , F. Segre , and C. Wiegand : Phys. Rev. , 76 , 897 (1949);~, 280 (1951) .
See, for example , I.-P. Bocquet, Y.Y. Chu, O.C. Kistner , M.L. Perlman , and G.T. Emery: Phys. Rev. Lett. ,12, 809 (1966); T.A. Carlson, P. Erman , and K. Franson: Nucl. Phys., AlII, 371 (1968).
3)

M. Fujioka and M. Takashima: I. Phys., 40 , C2-32 (1979).

4)

I.M. Band and V.I. Fomichev: Atomic Data and Nuclear Data Tables , 23, No.4 , p. 295 (1979).

54

111-1-15.

Highly Neutron Deficient Nuclei 157Yb

A. Hashizume, T. Katou, Y. Tendow,
and H. Kumagai

NUCLEAR REACTIONS

144Sm

ct6 0, 4n) E = 80 - 120 MeV, 1n-'Y, 'Y-'Y coin, 157Yb deduced levels, Ge(Li) detectors, enriched[target.

In a series of experimental studies carried out on the excited states in Yb isotopes by (HI,xn'Y) reactions, 1) the most neutron deficient nucleus whose states has been known is 158Yb. To
study the levels of more neutron deficient nuclei, states of 157Yb were populated by means of thecompound-evaporation reaction 144 Sme 6 0, 4n'Y)157Yb.
A self-supporting enriched 144Sm target was prepared by vacuum evaporation where 144S m2 0 3

was reduced by thorium.

Excitation functions in the incident energy range of 80 to 120 MeV

were studied by observing 'Y-ray singles spectra and also spectra of 'Y-rays in coincidence withneutrons. Since nothing is known of the excited states of 157Yb, precaution was taken to assure
the observation of the 6 0, 4n) reaction by compairing the excitation function with those of
147Smct60, 3n) 160 Yb and 147Smct60, 4n)159Yb. Levels of reaction products of the latter are wellknown. 2) It was also found that the n-')' coincidence technique was a good means to selecteneutron emitting channels. 3 )144

Sm + 16

The four fold coincidence spectra of E-y 1 - E-Y2 - t - T have been°

Excitation function____ - 543keV
~-

II

~

,.

cu

u

(j)

586keV144

Sm( 160 , 3n ) 157 Yb.--.......

V/
~
i

-ecu

494keV., 491keV
520keV//.

144

Sm( 160, 2n) 158 Yb~-A--""'358keV

2+-0+~.~ 477keV 4+-2 +

.I"

~.

Eo (MeV )Fig. 1.
158Yb.

Excitation functions of 157Yb and55measured where E')'l and E')'2 are the 'Y-ray energies , t is the time between two 'Y-rays, and T is thetime from a natural bunched beam of the cyclotron.
Figure 1 shows excitation function for the cI 60 , 3n'Y) reaction observed with some 'Y-rays andFig. 2 shows a spectrum of 'Y-rays coincident with neutrons when 144Sm was bombarded by 100
MeV 160. As shown in Fig. 2, three intense 'Y-rays, 491 , 543, and 586 keY , which coincide withneutrons were observed. When the gate was opened by 491 keY in 'Y-'Y coincident spectrum,
those 'Y-rays coincide as shown in Fig. 3. It was also shown that all of those 'Y-rays are emitted
in coincidence.
6000~----------------------------------------------------------------~

144 Sm + 160 ( lOOMeV)
..92

...0
>r'"

...0
>'"'"

<U
U
(f)
(1)

>

00

~ 4000LO(Y'")

n- y coincidence
...0
>r'"

m
"""

...0
...0 >-

(Y'")

(Y'")

LO
~~
"""

I

<:'0
j ~moo<..OLD

TI

(1)

c

C
<U

~

U

~

2000

0..

2c
:::J

o
U

OLL--------------~5~070--------------~1~0~07
0 --------------~1~50~0~--------~2~000

Channel number

Fig. 2.

Spectrum of 'Y-rays which coincides with neutrons.

144 Sm + O( 100 MeV)

..92
<U
U
(f)
(1)

>

:,::;
<U

~
(1)

c

C
<U

>

~

u

(1)

~

~

.---<

0..

~
c
:::J

(1)

"""2

(1)
~

"""

<..0
00

LO

(9

U

>

-"".
(Y'")

cu

0

>

m

LD

Channel nu mber

Fig. 3.

'Y-'Y coincidence spectrum gated by the 491 ke V 'Y-ray.

56

We tentatively propose the excited states in 157 Yb shown in Fig. 4.

Since 157Yb is an odd

nucleus, it is not yet evident if the proposed band corresponds to the ground band.

However, inview of these three ,),-rays being most intense lines in n - ')' spectrum , it is probable that the bandis the ground band of (7/2), (9/2), (11/2), and (13/2) states.

Further study is in progress.

1 626 + X keV

586( 75 )1 034 + X

543( 91 )491+X

Fig. 4.
491(100 )Proposed level scheme in lS7Yb.

Relative ')'-ray intensities observed at 90°
in the case of 90 MeV incident energy

157 YbO+ X

are shown in parenthesis.

References
1)

A. Hashizume, T. Katou, Y. Tendow , and H. Kumagai: IPCR Cyclotron Progr. Rep. , 14,
59 (1980) ; A. Hashizume, T. Katou, Y. Tendow , and H. Kumagai; ibid , !l, 74 (1978).

2)

F.A. Beck , E. Bozek , T. Byrski , C. Gehringer, J.C. Merdinger , Y. Schutz, 1. Styczen, andJ.P. Vivien: Phys. Rev. Lett. , 42, 493 (1979); W. Trautmann , D. Proetel , O. Hausser,
W. Hering, and F . Riess: ibid., 35,1694 (1975).

3)

A. Hashizume, H. Kumagai, Y. Tendow, and T. Katou: p.121in this report.

57

III-1-16.

Calculation of Gamma-Ray Multiplicity Moments
Associated with Massive-Transfer Reactions

T. Inamura and M. Wakai*

NUCLEAR REACTIONS
154 Sm (12 C , a4n)158 Dy , E = 85 , 109 MeV ;159Tb 4N, a5n)164 yb , E = 115 MeV ; 159 Tb ( lO B, 5n)164yb , E = 69e

Me V; massive transfer and fusion evaporation ; ,-ray average
multiplicity, variance , skewness calculated ; E and J distribution
effects.
The most distinctive feature predicted for the massive-transfer (or incomplete-fusion) reaction is the
localization of .e values in the entrance channel leading to fusionlike products. I ), 2) Consequently it is interesting
to study the ,-ray multiplicity distribution (m')' distribution) which depends on excitation energy and angularmomentum distributions of the entry states, i.e. , the excited states prior to , decay.
We have made a statistical model calculation to estimate the first three moments of the m, distribution for
the following systems from which the massive transfers were observed accompanying energetic a-particle emission: 2)
85 MeV 12C + I54Sm, 109 MeV 12C + 154Sm , and 115 MeV 14N + I59Tb. The first three moments J.1 ' J.1 ' andI

3

presented in Table 1:2= < (m,- <m,)O >, have been converted into the shape parameters for convenience as
the average ,-ray multiplicity <m,) the width (standard deviation)= vf"ii;, and the

J.1 , which are defined as J.1

a,nskewness s, = J.1 3 / a~.
Computation was made by combining the second part of the Monte Carlo treatment code ICARUS (RegionII)3) and the code GROGI2. 4) The time -consuming first part of ICARUS (Region I), which treats the multipleparticle evaporation, was replaced by GROGI2 because we found that when it is normalized , the entry-state
population peE, J) produced by the first part is not substantially different from that obtained with GROGI2.
a particles are treated as those emitted prior to successive particle evaporation from the system of interest.
Since there is no established way to construct the entrance-channel energy E and angular momentum
distribution peE, f) , we assumed that peE , f ) = p(E)· pee) , peE) and p(f ) being given by Gaussian forms.

.e

This

assumption is considered reasonably good for the present stage because gross properties of deexcitation process aremainly governed by the average values of E and .e, and by the widths a E and af' These values were estimatedfrom experimental information 2 ) and theoretical prediction. 5) Here we confine our remarks to the sign ofskewness sf"
As is seen from Table 1, the sign of s, is likely to be positive in the case of massive transfer , while being
negative in the case of complete fusion.

It should be reminded that the value of J.1 3 is generally quite large andthe sign of s, is determined by the sign of J.1 3 .

To test the present result we repeated calculations for all cases

presented in Table 1, changing the level density and the ratio of ,-transition strengths CE I : C M I : CE2 : C~~ll .
We have found that the sign of s, is not changed although its absolute value is affected.
Needless to say, the sign of s, depends on the asymmetry of J distribution .
the sign of s, is determined independently of the E- and J- widths of peE , J).

But it is not known whether

We examined how s, changes as afunction of peE, J), using peE , J) = P(E)· P(J) where peE) and P(J) were Gaussian distributions with fwhm ;0,E and;0,J, and mean values < E > and < J >.

It should be stated that the existance of the yrast line is taken into accountin the ,-deexcitation process (Region II). The result is, as illustrated in Fig. 1 by using typical values < E> =14.0 MeV and <J > = 24.0 h for I64Yb: The narrower J distribution tends to give a positive Sf' while thebroader one tends to reduce its value so that it becomes even negative; and the reverse is true of the E distribution* Department of Physics, Osaka University.

58

Table 1.

Shape parameters of )'-ray multiplicity distribution for products of massive-transfer
and complete-fusion reactions.

Reaction

Product

<m)'>

0)'

s)'

85 MeV 12C + 154Sma)

158Dy

11.2

2.3

0.12

109 MeV 12C + 154Sma)

158Dy

12.9

2.6

0.07

115 MeV 14N + 159Tb b)

164Yb

14.6

3.1

0.25

69 MeV lOB + 159Tb c)

164Yb

13.7

3.7

- 0.10115 MeV 14N + 159Tbd)

164Yb

18.4

4.6

- 0.05

a)
b)

c)

d)

The transferred fragment is 8Be.
The transferred fragment is lOB.
Fusion. The energy of lOB gives the excitation energy of the system that corresponds to theexcitation energy at the most probable energy of a particles emitted in the massive-transfer
reaction l59'fb(,4N, a5n)16 4Yb at 115 MeV.
Fusion evaporation.

0.4

0.2

>--

(E)=14.0 MeV(J) =24.0 n

Fig. 1.
Dependence of skewness s on the'Yentry-state E and J distributions : (a) 6E/<E> =•0.0, (b) 6E/<E> = 0.6 , and (c) 6E/<E> = 0.9.
Solid and open pOints represent s specifically'Ycalculated for massive transfer and for complete

(c)

.---~

(0)

(J)

(b)

0.0 ! - - -- - - - - - = " ' - - = - - - - - - - - - l
0(0)

-0.2
0.0

0.2

0.4
0.6
6.J/(J)

0.8

1.0

fusion, respectively (see Table 1): massive
transfer, 159Tbe4N, a5n) 164 Yb at 115 MeV(solid circle), and lS4Sm(12C, a4n)158Dy at
85 MeV (solid triangle) and at 109 MeV (solidstar); fusion, 159Tb(lOB, 5n)164Yb at 69 MeV(open circle), and 159Tbe4N, a5n) 164 Yb at
115 MeV (open square).

effect. (These tendencies are enhanced as < J > increases.) Therefore, in general, s)' becomes positive if ae
is small and a € is large, i.e., when values are localized in the entrance channel whose energy distribution is broad.

.e

In summary, the m)' distribution is expected to possess a positive s)' in the case of massive transfer (orincomplete fusion), being contrary to the case of complete-fusion reaction. In the light of the present study it isquite understandable that s)' measured by Geoffroy et a1. 6) seems to change its sign from negative to positive as
the emitted a-particle energy increases, reflecting the effect of reaction mechanisms. It is interesting to note that,in the 86Kr + 144Sm reaction at 490 MeV, s)' of the m)' distribution was found to be positive for the quasielastic
region, while to be negative for the deep inelastic region. 7 ) Although the reaction system is very much different
from the present examples , there may be some similarities in the reaction mechanisms if the sign of s)' is the same.
It would be very desirable to study the sign of skewness (or third moment) of the m)' distribution systematically inthe heavy-ion reaction.
This study was initiated at the Cyclotron Institute, Texas A & M University.

R,eferences
1)

T. Inamura , M. Ishihara , T. Fukuda, T. Shimoda, and K. Hiruta: Phys. Lett., 68B, 51 (1977).

59

2)

T.T. Sugihara: Proc. of Nobel Symp. 50, Sweden, June 23-27 (1980); Physica Scripta, 24, 108 (1981),
and references therein.

3)
4)

M. Wakai and A. Faessler: Nucl. Phys., A307, 349 (1978); M. Wakai, M. Muraoka, and A. Faessler: Phys.
Lett., 93B, 232 (1980).
J. Gilat and J.R. Grover: Phys. Rev., C}, 734 (1971); J. Gilat: Brookhaven Natl. Lab. Rep., No. BNL 50246.

5)

T. Udagawa and T. Tamura: Phys. Rev. Lett., 45,1311 (1980).

6)

K.A. Geoffroy, D.G. Sarantites, M.L. Halbert, D.C. Hensley, R.A. Dayras, and J.H. Baker: ibid., 43, 1303
(1979).
P.R. Christensen, F. Folkmann, Ole Hansen, Q. Nathan, N. Trautner, F. Videb ce k, S.Y. van der Werf, H.C.
Britt, R.P. Chestnut, H. Freiesleben, and F. Puhofer: ibid., 40, 1245 (1978).

7)

60

III-1-17.

Angular - Momentum Transfer and Alignment Following

Preequilibrium

a-Particle Emission in Heavy-Ion Reactions

H. Utsunomiya, T. Nomura, S. Kohmoto, and M. Sasagase

NUCLEAR REACTION

209BiC60, cd) , E = 120 MeV, 209BieoNe, af),

E = 134, 146 MeV; measured angular correlations.

lJ

If a fissile nucleus is produced in a nuclear reaction as one of the reaction products, angularcorrelations of the fission fragments in coincidence with the other product are known to giveinformation on the magnitude and alignment of angular momenta transferred in the reaction.

We

have applied this method to the study of "fast" a-particle emission in heavy-ion fusionlike
reactions in order to study the reaction mechanism relevant to this phenomenon. A series of a-f
angular correlation measurements were performed in 14N_, 16 0_ and 2~e-induced reactions on
209Bi .

We have already reported a result of the 209Bi(14N, af) reaction at 115 MeV,l) whichindicates that the preequilibrium a-particle emission mainly originates from entrance angularmomenta smaller than the critical angular momentum for complete fusion.
The present measurements in the 160_ and 2oNe-induced reactions were made at bombarding
energies of 120 and 134 MeV, respectively.

The grazing angular momentum is estimated to be 60

h in both reactions, being nearly equal to that in the 14N-induced reactions mentioned above.
These reactions are therefore conveniently utilized to study projectile dependence on the angularmomentum transfer and alignment following the fast a-particle emission.

In addition, themeasurement was performed in the 209BieoNe, af) reaction at 146 MeV to see an effect of thedifferent incident energies. The experimental a-f angular correlations obtained in the 16 0_ and2oNe-induced reactions have been found to be apparently very similar to those reported in Ref. 1.
A detailed quantitative analysis similar to that in Ref. 1 is now in progress.

ReferenceI)

H. Utsunomiya, T. Nomura, M. Ishihara , T. Sugitate, K. Ieki, and S. Kohmoto: Phys. Lett.,

105B, 135 (1981).

61

III-1-18.

Search for a - Decay from High Spin Yrast Region

M. Sasagase, Y. Gono, Y. Itoh,* T. Kubo,
M. Sugawara, * * and S. Hayashibe

NUCLEAR REACTIONS'.
[

12C + 208Pb , E lab = 80 MeV and 14N + 141Pr '1E1ab = 88 MeV; a-X-ray coin., E - 6.E counter telescope and LEPS
detector, enriched target.

Typical life time of equilibrium or pre equilibrium a-particle emissions in heavy-ion reactions
is roughly estimated to be in the order of 10- 21 second. On the other hand, a-emissions fromlonger-lived ('''' I 0 -12 - 10 - 13 second) high - spin states near the yrast line are also expected asreported by Grover et al.l)

It is

We refer to the former case as type I and the latter as type 2.

very useful for nuclear spectroscopy to identify these longer-lived a-emitting states of type 2.
Coincidence experiments between a-particles and X-rays were performed for this purpose.
In nuclear reactions concerning medium weight nuclei, the compound nuclei de-excite emitting
It is known that the vacancies produced in the K-shell of theatoms on occasion of nuclear reactions 2) will be occupied by electrons with the life time of about

neutrons, 'Y-rays and a-particles etc.

10 - 16 second, emitting the associated K X-rays.

Thus the a-particles of type 2 , emitted from thecompound nuclei after neutron emissions, should be coincident with the K X-rays of the compound
nuclei, although the a-particles of type I should be coincident with those of the daughter nucleiof the a-decay.
According to the above idea, a-X-ray coincidence measurements were done for the twosystems: 12C(80 MeV) + 208Pb and 14N(88 MeV) + 141pr. We used 12C4+ and 14N4+ beams
accelerated by the cyclotron and self-supporting 208Pb enriched target of about I mgj cm 2 and141 Pr target of about 2 mgjcm 2 .
26.7 - 1000 ,urn Si detectors.

Emitted a-particles were detected with a counter telescope of
Coincident X-rays were measured with a 1 cm 3 LEPS detector.

The four fold coincidence spectra of E - 6E - Ex - T Xa have been measured, where E and 6E
are the signals from the a-counter, Ex is the X-ray energy signal, and T Xa is the time relation
between the X-ray and a-particle.
Examples of a-singles and coincidence spectra are shown in Fig. 1.

For the 12C + 208Pb

system, some of known a-decay lines 3 ) from the ground and excited states of 216Ra were observed
to be coincident with the K X-rays of Ra and not with those of Rn.

The level scheme of 216Ra

and a-decay lines are presented in Fig. 2. The ground state of 216Ra decays with the life time of
0.18 X 10 - 6 second and the life times of the excited states are in the order of 10- 9 second. Thus
the a-decay lines from the excited states are relatively enhanced in Fig. I (c).

The multiplicityof K X··ray of Ra for the a-decay line from the ground state of 216Ra can be obtained from theintensity ratio of the coincidence spectrum relative to the singles spectrum of a-particles.
deduced to be '" 0.8.
* Faculty of Science , Tohoku University.
** Chiba Institute of Technology.

It is

62

(a)

2000

( b)

0

It

+
co

+

(C)

c

co

N

.--<
<'-1
N

<'-1

+

-

00

+

[+:

0

0::

("j

0::
-.0

-.0
.--<

;::;

r'l

0
E

CH ANNE L NUMBER

Fig. 1. (a) a-singles spectrum for the 208Pb( 12 C, 0') reaction(b) and (c) a -spectra coincident with K X-rays of Ra: (b) delayedcomponent (20ns :s; T Xa ~ 230ns) and (c) prompt component(T Xa ~ 20ns).

For the 14 N + 141 Pr system, a definite evidence of the a-emission of type 2 is not obtained
yet. An X-ray spectrum coincident with a-particles is shown in Fig. 3. In the K X-ray region of
Dy , unassigned 'Y-ray peak may exist and the exact yield of Dy X-ray could not be obtained. The
coincident yield of the K X-rays of Dy is estimated to be less than 1/2000 of that of Gd, where
the former is expected to asso ciate with the type 2 a-particles and the latter with the type l.

63

11 -

2.3341309. 110 +2.02503 14.68+

1. 71 04203.5
1.5069343.5
1.1634475.5
0.6879687.911.35(11. 59)

2~: R a 128

11.03( 11.27)
10.82( 11.06)
10.49( 10.72)

0Fig. 2.

Level scheme of 216 Ra (Ref. 3).

The'Y-ray transition energies are given in ke V unit ,whereas the a-decay energies and the level
energies are given in Me V unit.

The Q-valuesof the a-decays are given in parentheses in Me V
unit.

0+ 0

Fig. 3.
400
CHANNEL Nl' ~1BER

X-ray spectrum

coincident with a-particles forthe 141 Pr( 14 N, a) reaction.

References

1)
2)
3)

J.R. Grover and J. Gilat: Phys. Rev., 157,823 (1967).
J.U. Andersen, E. L CBgsgarrd, M. Lund, and C.D. Moak: Nucl. Instr. and Methods,

132,507 (1976).
T. Nomura, K. Hiruta, M. Yoshie, H. Ikezoe, T. Fukuda, and O. Hashimoto: Phys. Lett.,
58B, 273 (1975).

64

III-1-19.

In-Beamr-Ray Spectroscopy of

216 RaY. Itoh,* Y. Gono, M. Sasagase, T. Kubo,
M. Sugawara,** S. Hayashibe, K. Hiruta, and T. Nomura

NUCLEAR REACTIONS

208Pb( 12 C, 4n) E = 80 MeV; "(-"( coin., I-/e),I-/t), linear polarization ("().
[ detectors, enriched target.

216Ra deduced levels.

Ge(Li) and LEPS

This study is one of a series of experiments on high-spin states of nuclei in the translead
region.

In this report we give a preliminary result of in-beam ,),-ray spectroscopy on 216Ra.

We performed measurements of singles ,),-ray spectra, angular distributions, time spectra, ')'-')'
coincidences, and linear polarizations.

States in 216Ra were populated via the 208Pb ( 12 C, 4n')')reaction at E = 80 MeV.
Angular distributions of ,),-rays were measured at five angles from 8 = 34° to 90° with 72 cm 3
Ge (Li) and 1 cm 3 LEPS (Low Energy Photon Spectrometer) detectors. The LEPS detector wasused especially to resolve 344 ke V doublet (343.5 ke V and 344.2 ke V) and to observe 51.4 ke V,),-ray with good statistics.

This low energy 51.4 keY transition in 216Ra was found for the firsttime in the CX-')' coincidence study.I)

The data were fitted to the equation W(8) = Ao + A 2 P 2(cos 8) + A4 P4 (cos 8), where P 2 and P4 are Legendre polynomials.

The ,),-ray intensities wereobtained from the angular distribution coefficients Ao' Time spectra of ')'-rays with respect to
RF signals of the cyclotron were measured with 1 cm 3 LEPS and no long-lived (:< 10 ns)
component was observed. The ')'-')' coincidences were measured with Ge(Li) - Ge(Li) andGe(Li) - 15 cm 3 LEPS combinations. The latter combination was useful to confirm the 51.4 keYtransition.

Linear polarizations of ,),-rays were measured by using a Compton polarimeter with apair of high-purity Ge diodes. 2)
Figure 1 shows a preliminary level scheme of 216 Ra.

The order of transitions was determinedconsidering the total transition intensities taking account of the internal conversion coefficients
Up to (14+) level, we referred to Nomura et a1. 4 )(lCC).3)

The result of the linear polarization

measurements indicates that all transitions except the 344 ke V doublet below the (14+) level areelectric ones.

This confirms the parity of these levels.

In Fig. 1, the order of 344.2 keY and613.3 keY transitions is reversed comparing to that of Nomura et a1. 4 ) based on their transitionin tensi ties.
Above the (14+) state, we assumed E2 modes for quadrupole transitions (220.5 keY and
290.1 keY).

Half-lives for M2 transitions calculated from the Weisskopf estimateS) are longer than
100 ns for both E')' = 220.5 keY and 290.1 keY with the ICC corrections 3) while those for E2

ones are shorter than IOns.

The M2 assignments to these transitions are therefore thought to be

improbable because of the absence of the long-lived (:G 10 ns) component in the observed time
spectra.

The angular distribution of the 51.4 keY transition shows a dipole character.

We

assigned an E 1 mode to it because its transition intensity for M 1 case should exceed that of the688.2 keY, 2+ ~ g.s. transition.
* Faculty of Science, Tohoku University.
** Chiba Institute of Technology.

The order of the 220.5, 398.6, and 556.9 keY transitions could

65

not be determined definitely since it depends on whether two dipole transitions (398.6 ke V and
556.9 ke V) are E 1 or MI. In Fig. 1, three transitions were located according to their I-ray
intensities.

More detailed analysis is in progress.
5(19)290.1(5.7)(I 7)

220.5( 110)398.6*

4

556.9*

3

613.3(48.0 )

>

(j)

L

3442(54.0)
309.2(65.9 )2314906.0 )2035( 81.2 )"rr---+---

343. 5( 94.1 )475 .9(94.3 )688.2 ( == 100)oaFig. 1.
A preliminary level scheme of
216 Ra.
The blank arrows indicate
a-decay.4) Transition energies are in ke V
unit. The numbers in parentheses are
relative transition intensities. Errors ofthese intensities are less than 10 %. Twointensities denoted by asterisks could not
be given definitely.

See the text.

References
1)
2)

M. Sasagase, Y. Gono, Y. Itoh, T. Kubo, M. Sugawara, and S. Hayashibe: p. 61.in this report.
T. Matsuzaki, H. Taketani, M. Ishii, and M. Oshima: Nuc1. Instr. and Methods, 188, 63 (1981).

3)
4)F.RoseL H.M. Fries, K. Alder, and H.C. Pauli: A.D. and N.D.T., 1L 292 (1978).
T. Nomura, K. Hiruta, M. Yoshie, H. Ikezoe, T. Fukuda, and O. Hashimoto: Phys. Lett.,

5)58B, 520 (1975).
C.M. Lederer and V.S. Shirley (ed.): "Table of Isotopes, 7th ed.", John Wiley & Sons, Inc.,New York, Chichester, Brisbane, and Tronto (1978).

66III-2.

Atomic and Solid-State Physics

1.

A

Broad Range Crystal Spectrometer

Y. Awaya, A. Hitachi, and H. Kumagai

A broad range crystal spectrometer has been designed and constructed for the purpose of
studying the X-rays following the heavy-ion atom collisions with high resolution and high efficiency.
It analyses the X-rays of energies in the range from El to E2 simultaneously ( leI -eland e2 being Bragg angles corresponding to El and E 2 , respectively).
position sensitive proportional counter (PSPC) were used.

A flat crystal and a

The whole system of the spectrometeris shown in Fig. 1.

TAC

UNIV
COIN

:>
I

io n beam

Fig. 1.

Fig. 2.
chamber.

e2 I ~ 10°,

The whole system of the spectrometer.

A photograph of the spectrometer in the scattering

67

The PSPC is of a gas-flow type and operated at the pressure of 3 atm. The size of its window
is 10 cm X 1 cm and covered with 500 JIm Be sheet. A position signal is obtained from thecathode (multiwire cathode connected with a delay line of l.6 JIsec) and is gated by a pulse heightsignal from the anode. This reduces the background caused by the ')'-rays induced by nuclear
reactions and the X-rays with different energies. Spurious position signals caused by photons
incident within 4 JIsec are eliminated by using a pile-up inspector circuit.
The PSPC was mounted on an arm which can be rotated around the center of the surface ofthe crystal. This unit was set on a turn arm of the 75 cm-diameter scattering chamber, 1) so thatthe angular distribution of the X-rays can be measured. A photograph of the spectrometer in the
scattering chamber is shown in Fig. 2.
As an example of the spectrum obtained by using this spectrometer, the spectrum of Ti K
X-rays induced by 8l.2 MeV N ions is shown in Fig. 3. A strip target of 1 mm wide and 4 JIm
thick was used. The energy resolution of the spectrometer depends on the width of the X-ray
source, as well as the distance between the target and the crystal and that between the crystal and
the PSPC, which were 14.5 cm and 13 cm in the case shown in the figure. The crystal of
LiF(200) was used. The energy resolution of the spectrometer is comparable to that of thestep-scanning crystal spectrometer2 ), 3) reported previously with a flat crystal and Soller slits andthe data taking time is significantly reduced, e.g. by a factor of 20 in this case.
The detailed report on this spectrometer will be given elsewhere. 4 )Energy ( keV)

4.8

4.6

4.4

Ti

3
Q)

c
c
o
..c

xlO

u

~

2

(j')

C

::J

o

U

O~===6=OhO====~~~~~~==~=-~;=~=-----~~======~1~400
Channel nu mber

Fig. 3.

Spectrum of Ti K X-rays induced by N ions obtained by thisspectrometer.

The symbol Km Ln denotes the m K-shell and n L-shellvacancies in the initial state.

68

References
1)

T. Fujisawa and Y. Awaya: IPCR Cyclotron Progr. Rep., 1., 54 (1967).

2)

Y. Awaya, A. Akiba, T. Katou, H. Kumagai, Y. Tendow, K. Izumo, T. Takahashi,
A. Hashizume, M. Okano, and T. Hamada: ibid,!Q, 78 (1976).

3)

Y. Awaya, M. Akiba, T. Katou, H. Kumagai, Y. Tendow, K. Izumo, T. Takahashi,
A. Hashizume, M. Okano , and T. Hamada: Phys. Lett., 61A, III (1977).

4)

A. Hitachi, H. Kumagai, and Y. Awaya: Nucl. Instr. and Methods, (in press).

69

III -2-2.

Angular Distribution of X-Rays Following
Multiple Inner Shell Ionization

A. Hitachi, Y. Awaya, T. Kambara, M. Kase,
H. Kumagai, T. Tonuma, and A. Yagishita
Angular distributions of Ti K X-rays and Sn L X-rays induced by N-ion bombardment havebeen measured using a broad range X-ray crystal spectrometer.1), 2) Ti (1 mm wide and 4 J,lm
thick) and Sn (1 mm wide and 1 11m thick) targets were excited by 81.2 MeV N 7+ ion beam fromthe cyclotron. A flat crystal of LiF (200) was used for the dispersion of X-rays.
Typical spectrum obtained for Ti is shown elsewhere.1) The relative intensities of K~ andK{3 satellite lines to that of K~ diagram line are plotted as a function of emitted photon angles
in Fig. 1. These satellite lines are found to be isotropic within experimental errors assuming thatK~ line is isotropic.
Spectra obtained for Sn L X-rays at various photon angles are shown in Fig. 2. Anisotropy
was observed for some satellite lines. The analysis of the data is in progress.
[ NERGY ( keV)

3 .4 5

3.5

3. 55

3.4

Sn LX- rays
1210

T j K X-roYs
O---o~~---u'1Ptp---~---VO

KLoi ---- - - - -nK8c_ - - rL - - - - 100

10

_.

-

- -~ - -

--

-

-

KL 20

6

W

~

-

~~-.

~
>

-

•__----4.___- -___

>I-

6

50

-

6

-

- 140· - 125"

-

66 -

6

90"

45"

PHOTON ANGLE

Fig. 1.

Angular distribution of Ti K satellite

lines

following 8l.2 MeV N7 + bombardment

relative to K~ diagram line.

1000

1200
CHANNEL NUMBER

Sn L X-ray spectra at
Fig. 2.
various photon angles excited by
8l.2 MeV N7 + ions.

References
1)
2)

Y. Awaya, A. Hitachi, and H. Kumagai: p. 66 in this report.
A. Hitachi, H. Kumagai, and Y. Awaya: Nucl. Instr. and Methods, (in press).

1400

70

III -2-3.

Ionization of Gases by Ion Bombardment

T. Tonuma, A. Yagishita, M. Kase, T. Kambara,
Y. Awaya, H. Kumagai, and 1. Kohno

In order to obtain information on multiple ionization in ion-atom collisions, we set up an
experimental apparatus to measure charged ions of gas targets by ion bombardment. The apparatus
used in producing charged ions is shown in Fig. 1. A beam of ions is crossed by a gas target
emerging from a gas jet of I mm in diameter and ionizes gas atoms.

Charged ions are extracted

in the direction perpendicular to the beam direction by an extraction electric field produced byparallel plate electrodes with a slit and are focused by an Einzel lens and an analyzer magnet.
Charge-analyzed ions, which are deflected through 90° along the curve of 16 cm radius by the
analyzer magnet, are detected by a channeltron detector. The magnetic field of the analyzer
magnet is kept constant and charge spectrum of the ionized gas target is observed by scanningelectric potentials of the parallel plate electrodes.

The apparatus has two 6" oil diffusion pumps(P 1 ,P 2) and one 2/1 oil diffusion pump (P 3 ).
Figure 2 shows the Ar charge spectrum produced by 84 MeV N 4 + ions obtained by thecyclotron. The magnetic field was kept at 1.1 kG. The background pressure was 3 X 10 - 6
Torr. When Ar gas was introduced at a rate of I cc/min, the pressure rose to about 8 X 10 - 5
Torr.

Charge states up to Ar 7 + were observed.
X 10

2.0

Gas jetParallel electrode

4

A+
r

1.5
u

c

LO

........
V>

c

8 1.0
Einzel lensCharge analyzer

Fig. 1.
apparatus.
pumps.

Schematic diagram of the
PI' P 2' and P 3 areFig. 2.
Ar charge spectrum by
84 MeV N4 + ions .

71III -2-4.

Target Gas Pressure Dependence of X-Rays from110 MeV Ne9 + Ions

T. Kambara, Y. Awaya, A. Hitachi, M. Kase,
1. Kohno, H. Kumagai, and T. Tonuma

The energy spectra of K X-rays from 110 MeV Ne 9 + ions (hydrogen-like) in gaseous targets
were measured at various gas pressures ranging from 0.5 to 300 Torr. The targets were H 2 , He,
CH 4 , N 2 , 2 , Ne, and CH 3 0H. A Si(Li) detector with a resolution of 240 eV (FWHM) for 6.4
keY X-rays was used for the measurements. The experimental set-up was reported previously.1)
In the spectra of the X-rays, two peaks appear around I keY which correspond to the K
X-rays from the Ne 9 + ions. The X-rays from the 2p - 1s transition (1.02 keY) make one peak at°lower energy and those from the np - I s transitions with n greater than 2 (1.21 - 1.36 keY)
make another peak at higher energy. The resolution of the detector could not resolve the latterpeak to each transition but high resolution measurement with a crystal spectrometer verified thatthe excited states up to n = 6 contribute to the peak.1)
The spectra obtained were fitted to the sum of two Gaussian curves by the least square
fitting. The position, width and yield of each peak were compared for various gas species andtheir pressures.
We have found some differences in the pressure dependence of the spectra among gas species.
For light gas targets (H 2 and He), the yield of the X-rays for both peaks are not proportional tothe pressure but the yield normalized to the pressure decreases greatly when the pressure increases,

0

1.26. 2p-l s

-:::
c

:::l

C

onp-l s(n>2)

100

:;

co

•

>~
c

0

~

Q)

:::l

Q)

Cf)
Cf)

~

.~

.:,c.

<l:

1.25

.:,c.

50

cu
Q)

CL
-0
-----ill

0

0

Q)

..0

Q.

.~

0

>=

•

o He

~

~

• N2

•
Ga s pre ssure (Torr )Gas pressure (Torr )Fig. 1.

Gas pressure dependence of theyield of X-rays normalized to the pressureof He gas target. Closed circle: 2p - 1stransition; open circle: sum of np - Istransitions (n > 2).

Fig. 2.

Gas pressure dependence of thepeak position from np - 1s transitions(n > 2). Open circle: He gas target;
closed circle: N2 gas target.

72

as shown in Fig. 1.

For the other targets, the yield seems to be proportional to the pressure.

The position of the peak from the 2p - 1s transition does not change with the change of pressure,but the peak at higher energy, which is a superposition of the unresolved peaks from the np - Istransitions (n > 2), shifts to lower energy when the pressure increases.

One exception is the caseof He gas target where both the peaks do not shift greatly. Figure 2 shows the pressure
dependence of the position of the peak at higher energy in N2 and He targets.
The non-linear pressure dependence of the X-ray yield in the light targets is considered to be
due to small electron transfer probability from the target molecules into the projectile ions. The
OBK model 2) predicts the cross section values of about 10- 2o cm 2 for H2 and He targets, which aresmaller than those for the other targets by 10 - 3 - 10 -4. Therefore projectile ions in the lighter
gases do not exchange electrons with the gas molecules frequently enough to reach the equillibrium
charge state distribution in the gas before they get to the detection area. The fraction of Ne 9 +ions in the projectiles may be smaller for higher target pressure which means larger target thickness
from the entrance of the target cell, and the K X-rays from the Ne 9 + ions may not increase inproportion to the gas pressure.
The energy shift of the peak from the np - 1s transitions (n > 2) is considered to come fromthe collisional quenching 3) of the higher excited states of the Ne 9 + ions. When the ions are inhigher excited states, they have longer lifetime and larger cross section of collisions with the target
molecules than those in lower states, and they can more easily be changed to other states bycollisions before they emit X-rays. The collisional quenching process becomes more dominant forsmaller mean free path of the ions in the gas, which is inversely proportional to the gas pressure.
The X-rays following the transitions from higher levels disappear when the gas pressure increases
and the observed peak shifts to lower energy. The small shift of the peak in the case of He target
may be interpreted by assuming that the collision cross section between the excited Ne ions and
He atoms is smaller than those between the Ne ions and other molecules.

We expect to obtain

the information of the collision cross section between excited ions at high charge state and various
gas molecules by making more detailed experiments and analyses of the X-ray spectra.

ReferencesI)

T. Kambara, Y. Awaya, A. Hitachi, M. Kase, 1. Kohno, and T. Tonuma: IPCR Cyclotron
Progr. Rep., li, 88 (1980).

2)

H.D. Betz: "Method of Experimental Physics", (Ed. L. Marton and C. Marton), Academic

3)

Press, New York, !2, 96 (1980).
D.L. Matthews, R.J. Fortner, and G. Bissinger: Phys. Rev. Lett., !l, 664 (1976).

73

III-2-5.

Chemical Effects on F, AI and Si Ka, and Cu La
Satellite Spectra Produced by 2.4 MeV He + +M. Uda, K. Maeda, Y. Sasa, and A. Koyama

Chemical effects have been reflected in intensity distributions of X-ray satellite spectra related
to the multiple ionization. Rather pronounced change in the intensity distribution has been
observed in F Ka spectra 1)- 3) which are originated from the electron transition between theoutermost and I s shells.

However, the change has been depressed in the innershell-innershelltransitions, such as AI, Si, S, and CI Ka's.4), 5)

It is difficult to compare the change in theintensity distributions for these elements directly because the experiments have been carried out
under different conditions.

In the present experiment, the same excitation condition (2.4 MeVHe++) was employed for all the elements studied.
He++ was accelerated by the Tandetron (General Ionex Corp.).
equipped with a rubidium acid phthalate (010) flat crystal.

A Bragg spectrometer was

NaF, AIF 3' CuF 2 for F Ka, Al and

AIF3 for Al Ka, Si and Si02 for Si Ka, and Cu and CuF 2 for Cu La, (3 were used.

~~~~

NaF

~~"S::: ~

Z:'

.li)

c

.....
(J)

oS

£Vl
C

(J)

>

(J)

c

~
(J)

a:

(J)

.~

.....m

Al

Q)

a:

670

680

690

1460

Energy (eV)Fig. 1.

F Ka satellite spectra

produced by 2.4 MeV He++.
means the K absorption edge.

1500

1540

Energy (eV)Kab.

Fig. 2.
Al Ka satellite spectra
produced by 2.4 MeV He++.

74~":.J~~
~~~~

>-

£Vl

~

Vl
C

C

Q)

Q)

C

-

C

QJ

>

Q)

.~

Cu

~
Q)

n;

Qj

.b

0::

0:

~

.:i

+

1700

1740

1780

1820

Energy (eV)Fig. 3.
Si Ka satellite spectra
produced by 2.4 MeV He++.

920

940

960

Energy (eV)Fig. 4.
eu In, {3 satellite spectra
produced by 2.4 MeV He++.

Prior to the X-ray emission, electron vacancies produced in the valence band are expected tobe filled with valence electrons localized on ligand atoms.

Enhanced chemical effect should thenbe observed on the intensity distribution of the X-ray satellite spectra which are originated fromthe transition of the valence electrons to the inner shell (Fig. I for F KO' and Fig. 4 for Cu La, (3).
For elements whose X-ray emission relates indirectly to the electron vacancy transfer between theatoms of interest and surrounding atoms, much smaller chemical effect than that of the former is
expected to be seen.

This is indeed the case in Al KO' and Si KO' as shown in Figs. 2 and 3,

respectively.

References
1)

M. Uda, H. Endo, K. Maeda, Y. Awaya, M. Kobayashi, Y. Sasa, H. Kumagai, and T. Tonuma:

2)
3)
4)

Phys. Rev. Lett., 42, 1257 (1979).
H. Endo, M. Uda, and K. Maeda: Phys. Rev., A22, 1436 (1980).
M. Uda, H. Endo, K. Maeda, Y. Sasa, and M. Kobayashi: Z. Physik A., 300, 1 (1981).
P. G. Burkhalter, A. R. Knudson, D. J. Nagel, and K. L. Dunning: Phys. Rev., A~, 2093

5)

( 1972).
R. L. Watson, A. K. Leeper, B. I. Sonobe, T. Chiao, and F. E. Jenson: ibid., 12,914( 1977).

75

Chern ica I Effect on 0

III -2-6.

K a Satell ite Spectra

Induced by 2.4 MeV He++ Ions

K. Maeda, Y. Sasa, K. Fuwa, and M. Uda

We have extensively investigated the chemical effects on the intensity distributions of the X-ray
satellites due to multiple ionization.!) - 4) The present paper deals with the He++ -ion induced
K~ satellite spectra obtained from a series of oxygen compounds.
2.4 MeV He++ -ion beams accelerated by the Tandetron (General Ionex Corp.) were used togenerate the Kl L n states for oxygen, where KI L n denotes a configuration with a single K and n L°vacancies.

Target materials used were films of MgO, A1 2 0 3 , Si02 , CuO, and Na 2 S04 , all in 1- 6

mg/cm 2

thickness. The emitted X-ray spectra were recorded on a Bragg spectrometer equippedwith a flat analyzing crystal.

°

The intensities of theK~ satellites are supposed to be weak because in the compounds ofsmall ionicity such as oxides, considerable number of the L shell vacancies generated at the timeof ion impact may be filled with the valence electrons of the surrounding atoms prior to the X-ray°

emission. I) Therefore, we magnified theK 1 L 2 satellite intensity utilizing a particular analyzing
crystal, rubidium acid phthalate (RAP) to make clear the small change in the satellite intensities.
RAP has a reflectivity spike at 532 eV where theKl L2 satellite is just situated. Electron
induced°°K~ spectra of MgO analyzed with two kinds of crystals, RAP and clinochlore, are shownin Fig. 1 to demonstrate such an anomalous reflectivity of RAP. The spectrum obtained by RAP
shows a peak at 532 eV, whereas no peak is detected at this energy region when the clinochlore isused, whose reflection coefficient is almost constant within the measured energy range. S ), 6) The
energies of K 1 L 1 and K 1 L 2 satellites given in the figure were calculated, on the basis of the sudden
approximation, by the DV-X~ method 7 ) and were determined by referring to the energy of the
diagram line (K 1 LO).

The reflection coefficient of RAP at 532 eV was evaluated to be about 4
<::.;

--.-J

~

Y

-y

~

I

I

clinochlore

1keY e~~tvlgO

"iii

c

!

-

--

<IJ

>

:;
&

RAP
8 keY e~MgO

Fig. 1.

520

525

530

Energy (eY)535°Electron induced
Ka
spectra of MgO analyzed with RAP
and clinochlore.

76

Oxygen Ka
2.4 MeV He2+ ~

c =
.27

..... -..

cuO : :...
# -,

. 53

•

.. .','.

./,,"'--.....' '.

.37.........

........

......

.QO.4

~

. 49

. 63

.::

. .. : .......
520.......

. .....

e•

'-.
525

530 535

520

Energy (eV)Fig. 2.

°..........

.,

.....
525

o0

530 535

Energy (eV)Ka spectra of MgO, A1 20 3 ,Si0 2 , CuO , and Na 2 S04 induced by
2.4 MeV He++ ions.

RAP was used as

the analyzing crystal.

C means the.

• --_.--• --- --•

-- -

0.2

0.4
Q6
Covalency

0.8

Fig. 3.

The observed intensity ratio of2
the K L satellite to the diagram line of1° Ka against the covalency .

covalency calculated from the relation ,C = I - I, where I is the Pauling ionicity.8)
times larger than that in the neighbouring energy region.

°

The He++ -ion induced
Ka spectra analyzed with RAP are shown in Fig. 2 . A strong peakidentified as theKl L2 satellite is found in each spectrum. The observed intensity ratios of the°satellites to the diagram lines are plotted, in Fig. 3 , against the covalency of the compounds.
intensity ratios tend to decrease with the increase of the covalency.
with the results for F Ka spectra. 1) - 3)

The

Such a trend is consistent

The crystals such as RAP and KAP, which have a reflectivity anomaly, have been considered
to be unsuitable for X-ray analysis . However, making use of RAP as the analyzing crystal, we
could magnify the weak 0 K 1 L 2 satellite and could detect the chemical effect reflected in the 0
Ka satellite spectra, successfully.

References
1)

M. Uda, H. Endo , K. Maeda , Y. Awaya, M. Kobayashi, Y. Sasa, H. Kumagai , and T. Tonuma:
Phys. Rev. Lett., 42, 1257 (1979).

2)

H. Endo, M. Uda, and K. Maeda: Phys. Rev., A22, 1436 (1980).

3)

M. Uda, H. Endo , K. Maeda, Y. Sasa , and M. Kobayashi: Z. Physik A , 300, 1 (1981).

4)

M. Uda, K. Maeda, H. Endo, Y. Sasa, and M. Kobayashi: IPCR Cyclotron Progr. Rep., !.l, 86(1979).

u., 352 (1970).

5)

R.L. Blake: Adv. X-ray Analysis,

6)

K. Maeda and M. Uda: Adv. X-ray Chemical Analysis (Japan), ~ 19 (1976).

7)8)H. Adachi, M. Tsukada, and C. Satoko: J. Phys. Soc. Japan, 45, 875 (1978).
L. Pauling: "The Nature of the Chemical Bond", 3rd ed., Cornell Univ. Press, N. Y. (1960).

77

III-2-7.

Preliminary Experiments for PIXE

K. Maeda, Y. Sasa, and M. Uda

Preliminary experiments have been carried out to obtain optimum conditions for PIXE
( a)

Blood No 008
5.0 MeV H+ 59,u C

...
I

I

I

I

I

4

I

8

I

I

12

I

I

16

20

(b)

Fe

Bl ood No. 008". Fe

5.0 MeV H+ I7,u C

. .,,

,,,
.
, "

10 3 -

/

Q)

<:

~

c

C
r<:J

...c

U

Zn

t

~

' "

\

~ 10 2 ~.;
::J

8

~I.

Br

':'....,..

e.-•; ..' :' :..

-.~,". : .

-:":'.'" , ' / ' I.#ItI. ~' •

Br

:

'/_1
Of

J.:

..

.

.1t:. ... :.:...
•.

(o\ . . . . . . . "":,:::~::::..
....\:.:_-_:.:'". ...~...,..'.
...
'

!

I

4

I

I

8

I

I

I

12

I

16

I

I

20

x- ray energy ( keV )Fig. 1.
X-ray spectra of blood from a healthy person induced by
5.0 MeV H+ ion impact ; (a) without absorber and (b) with a 60 J.1m
A 1 absorber.

Backings are Mylar foils.

78(particle induced X-ray emission) analysis.
Our present interest is in finding the correlations between diseases and trace element
concentrations in biological tissues. At the first .step we chose healthy whole blood as samples toestimate the mean composition of normal human blood. The blood samples treated with
anticoagulant were deposited on 4 11m thick Mylar films or 250 11m thick Be foils. The
anticoagulant used was potassium salt of EDT A. The impurities contained in the backings are
as follows: Ca in Mylar; AI, Si, Fe, and Ni in Be. Two kinds of ion beams, 5.0 MeV H+ and
2.4 MeV He++ accelerated by the cyclotron and the Tandetron (General Ionex Corp.), respectively,
were utilized to induce characteristic X-rays. The emitted X-rays were detected by a Si(Li)detector (FWHM = 200 eV at 5.9 keV) and processed by a multichannel analyzer. In some cases
X-ray absorbers were inserted between the sample and the detector to depress undisired X-rays.
A dozen of the samples were analyzed with this method. Typical spectra taken with anwithout X-ray absorber for the blood sample induced by 5.0 MeV H+ ion impact are represented
in Fig. 1.

Eight elements, P, S, Cl, K, Ca, Fe, Zn, and Br, were detected.

No significant

difference in the elemental concentrations was observed among the samples used here.

Theability of the Tandetron for PIXE analysis was also checked by use of one of the blood samples.
The spectrum shown in Fig. 2 indicates that the Tandetron is particularly suitable for the analysis
of light elements. Further investigation is in progress for the choice of appropriate experimental
parameters, such as bombarding energy, particle type, absorber, backing etc.

CI

S
p~.'

103 r

Bl oodK

Si ::: ~ ;.
AI " . . '

.....

Q)

: .. Ca'"cc~ 10 2 ~/~No. 002

2.4 MeV He++50,u C

. "-.

Fe

~

c

~

o

U

.. - ...- - .__ ....
I

o

2

1

4

6

8

10

_- ......-

I

I

12

14

X- ray energy (ke V)

Fig. 2.
X-ray spectrum of blood from a healthy persons induced by
2.4 MeV He++ ion impact without absorber. A Be backing is used.

79

III-2-S.

Backscattering Spectra from Silicides

M. Uda, K. Hirose, N. Yokoyama, N. Imajo,
1. Odomari, K. Fuwa, and Y. Sasa

The Schottky barrier is formed at the interface between a metal and a semiconductor. Its
height for Si and silicide contact has been reported to be related linearly to the heat of formation 1)
and the work function 2) of silicides. However, Pt-Si and Ir-Si systems are exceptions to such
empirical law. To get the general rule, bonding natures or electronic structures of outermost
shells of the silicides have to be investigated and classified systematically. For this purpose theefforts to measure ESCA spectra of the silicides are indispensable.
A series of silicides is formed on Si by evaporating various metals on Si (111) in vacuum andallowing them to diffuse into the substrate silicon.

Thickness of the silicides formed is governedby annealing temperature and duration. A degree of silicide formation was checked by thebackscattering technique for which the Tandetron (General Ionex Corp.) was used. 2.1 MeV
He++ beams were focused on specimens, whose diameter was 1 mmet>.
Backscattering spectra taken from a Ni-Si system are shown in Fig. 1 (a) - (c).

7JWhen the

( a)

"~

500

'\..... .

:. . .i:"'-'-..../'

250
if)
~

o

u

:::2
.~

Ot-----------~~

:

( b)

.

:..r ' ....

1 500

no

Fig. 1 (a).

cBackscattering spectrum fora Ni-Si system annealed at 325° C for 2 h.
500'.

A peak at the right hand side is that~.:'\.,,:

o t-------------'.~·-::'--.

3000:","J'/( c)

2 OOO fr----.. . . . . .\
1 000

.:
\.
\~

:'
......

0~~110~-~9~0--'~~1~LiO---2~50J;---Ihl
Channel numberof pure Ni at the outermost layer.

The

second peak which looks like a shoulder
to the first peak is that of Ni in Ni2 Si.
The third one is that of Si in Ni2 Si.
The forth one is that of pure Si which isthe substrate. (b) Backscattering spectrum
for the system annealed at 300°C for 17 h.
(c) Backscattering spectrum for the same
system, but annealed at 500° C for I h.

80

annealing temperature was low, pure nickel layer still remains at the outermost surface of thespecimen. Thus, the surface structure is described as Ni-Ni 2 Si-Si in regular sequence from thesurface.

After high temperature annealing, for example at 500°C, diffusion between Ni and Si

is almost completed as shown in Fig. I (c).

The sample thus heat-treated will be submitted to

ESCA measurement.

ReferencesI)
2)

J .M. Anderews and J.C. Phillips: Phys. Rev. Lett., li, 56 (1975).
J .L. Freeouf: Solid State Commun., 33, 1059 (1980).

81

III-2-9.

High Resolution Electron Spectrometer

A. Yagishita, M. Saito , and K. Nishi

Design, construction, and preliminary testing of the Auger Electron Spectrometer (AES) havebeen previously reported.1) The AES was constructed on the crossed-beam principle, and consists
basically of a molecular gas beam target, a high resolution electron energy analyzer , and a highintensity electron gun which is installed to calibrate the electron analyzer. The analyzer can berotated relative to an incident ion-beam about the axis of the gas beam, to enable ejected electron
spectra to be studied over the range of ejection angles from 20° to 160° .
The electron gun was designed to produce a well defined image of an electron source (in thiscase a tungsten hairpin filament) that could be focused onto the target gas beam in the energy
range from 200 eV to 7000 eV. This image is typically formed by a current between I J1A and
10 J1A , depending primarily on a space charge limitation imposed by the energy of the electrons.
The molecular beam flows out from a thin stainless steel tube of inside diameter 0.5 mm andlength 10 mm. In the target region , the pressure is typically 10- 3 Torr , while the backgroundpressure in the system is two order of magnitude lower. This situation is maintained by two turbo
molecular pumps, one with a pumping speed of 510 f /sec and another of 360 e/sec.
Electrons emitted from the small interaction region enter into the entrance of the analyzer
which consists of electron-optical lenses and an electrostatic energy filter of hemispherical shape.
6.0
KRYPTON
5.0

C'l
N

Z

M

N

Z 10
V

~

4.0

C'l
M
C'lNC'lN

zz
I

v

x

3.0

z

0

(.)

~~

1/

if)

I-

=>

1

~~
v v

0

C'-.C'-.

II

2.0

1.0

280.00360.00240.00320.00CHANNELS

Fig. 1.
The MNN Auger and MMN Coster-Kronig spectrum of
krypton by 2000 eV-electron impact.

82

The electrons having the correct energy to pass through the energy filter are detected with achannel electron multiplier operating in the pUlse-counting mode. Pulses from the detector are
accumulated in a multichannel scaler which performs the function of signal averaging . A linear
ramp voltage, synchronized with the horizontal sweep of the multichannel scaler, is used to definecertain potential energy such as the ejected-electron energy within the analyzer.
Figure I shows the MNN Auger and MMN Coster-Kronig spectrum of Krypton by electron
impact.

The energy of incident electrons is 2000 e V and the electron-ejection angle is 108° withrespect to the primary beam direction. Some experimental results on those Auger and CosterKronig processes induced by electron impact have been already published. 2 ), 3)
Figure 2 shows the KLL Auger spectrum of neon by electron irnpact. Because the spectrum
has been studied by many investigators, we can easily estimate the energy resolution of the AES.
From the spectrum , we deduce the energy resolution to be a few parts in 104 .
10.0

13

NEON

~

.......,

'"

N

9.0

.-J

'"

N

.-J

~

8.0

7.0

6.0

0

x
.......,

5.0

0::-

(/)

c

~

~

0

0

.-J

4.0

~
(/)
(l)

3.0

0

(f)

:::......

2.0

~
~

c

~

N

rf
~

:J

"---'

2

.-J

(/)

0

c

(j)

(j)

c
.-J

2
2

"---'
N

.-J

~
~

~

1.0

00
0.00

Channels

Fig. 2.
The KLL Auger spectrumof neon by 2000 e V-electron
impact.

References
1)

A. Yagishita and T. Nakamura: IPCR Cyclotron Progr. Rep., li, 143 (1980).

2)
3)

A. Yagishita: Phys. Lett., 87A, 30 (1981) .
A. Yagishita, H. Hanashiro, S. Ohtani, and H. Suzuki: J. Phys. B, .!..i, L 777 (1981).

83

III-2-10.

Parallel Plate Electrostatic Spectrograph
Using MCP and PSD

A. Yagishita and K. Agata

Conventional spectrometers usually involve using an energy or mass analyzer, which produces
dispersion, and scanning an image across a slit. This procedure detects at one time only a smallpart of the spectrum.

The resolving power of the instrument is determined by the width of theslit: the narrower the slit, the better the resolution; but this must be paid for by a reduction insensitivity since only a part of the available signals will now be transmitted through the slit. To
remedy this situation and make use of the whole image, a multidetector system is needed that cansimultaneously detect all the events.
The system we are developing uses a microchannel plate (MCP) image intensifier to amplify
the extended image produced by an electron energy analyzer. The electrons produced by the
MCP are accelerated on to the surface of a position sensitive device (PSD; manufactured byHamamatsu TV Co., Ltd.). The electronic charges are divided by the resistance of the PSD's
surface into two parts, qA and qB' which are inversely proportional to the resistances, RL - Rx
and R x ' to the electrodes A and B, respectively (see Fig. 1). One can determine the position of
the incident electrons by calculating qA /(qA + qB) and the data are stored in a multichannel
pulse height" analyzer.

---I=jMep _ _PSD
8

qB =R L -

Rx

Rx

qA

x

=r

Fig. 1.
Schematic diagram of
position analyzing electronics.

For the operation of this multidetector system, we have newly designed a simple parallel plateelectrostatic electron-energy analyzer. Our design of the analyzer has mostly followed the idea
developed by Green and Proca. 1 ) Their consideration of the focusing properties of a parallel
plate analyzer indicated that it is possible to select a given angle () of entry into the field for which
second order focusing can be attained giving rise to an angular aberration term proportional to(6.())3.

In fact, for () = 30°, the angular aberrations are minimized, allowing one to built ananalyzer of reasonable resolution with a wide angular acceptance.

84

8 16
22
4

125

Fig. 2.
Schematic drawing of the parallel plate electrostatic electronenergy analyzer.

Figure 2 shows the schematic drawing of the analyzer designed according to the prescription
mentioned above.

Design parameters of the analyzer are written in Fig. 2 in units of mm.

Theposition sensitive detector system (Mep and PSD) is settled on the exit focal plane and the whole
spectrum can be obtained at once.

Reference
1)

T.S. Green and G.A. Proca: Rev. Sci. Inst., ±l., 1409 (1970).

85

III -2- 1 1 .

Beam-Foil Spectroscopy

K. Ando and K. Mori

An automatic system for measurement of spectral intensities against wavelength or foil position
has been prepared and is schematically shown in Fig. 1.
Two modes of measurements are selected on a control panel.

The first mode is formeasurement of spectrum emitted from the excited ion beam transmitted through a carbon foil.
The second mode is for measurement of decay curves of spectral line intensities against the distancefrom the foil position. In each mode, the wavelength or the foil position is automaticallychanged by a given amount by means of the stepping motor connected with the scanning systemof the spectrometer or the foil carriage , after each scanning system receives a trigger signal. This
trigger signal is produced by a preset counter whenever the number of ion particles which arecollected in a Faraday cup reaches the preset value of the counter so as to normalize the spectral
intensities by the number of ion particles.
The data in the measurement, that is, foil position, wavelength, photon number, etc., arestored by data aquisition system of a computer.

Stepping
motor

Ion

o Measurement of Spectraoro Measurement of life time
Control panel

Fig. 1.
An automatic measuring system for the beam-foil
spectroscopy.

86III-2-12.

Optical Detection of Atomic and Nuclear Spin Polarization
Produced by Beam-Foil Interaction

S. Kohmoto, M. Ishihara, T. Nomura,
Y. Gono, and M. Sasagase
It has been shown 1) that low energy (~ few MeV) ion beam after passage through a thin foil

whose normal is tilted relative to the beam axis is not only atomically excited but also polarized.
This polarization can be determined by measuring the circular polarization of light emitted fromthe excited ion beam. The atomic polarization is then transferred to the nucleus via hyperfine
interaction. An optical detection of the nuclear spin polarization is also shown 2 ) to be possible
with the aid of a second thin foil placed downstream vis-a-vis the first and perpendicularly to thebeam direction.
We are interested in, with use of these techniques,(1) to generate nuclear spin polarized ion beams and to accelerate them moreover toenergies which are suitable for the study of nuclear physics(2) and to measure the nuclear polarization of particles which are produced in nuclear
reactions.
In an attempt to look for these possibilities, we are going to measure the circular polarizationof light emitted from the 14N beam accelerated to few hundreds keV by the injector of the Linac
Accelerator (Fig. 1). The interference filter is used for the purpose to select a particulartransition in nitrogen atom. Single photon counting measurement will be done by the aid of aphoto-multiplier (PM) with low dark counts « 1 cps).

Preliminary tests are in progress.

- - - - - b eam
to Faraday cup - - - .

Fig. 1.

rotat in g A / 4 plate -Schematic experimental

arrangement to measure the circularpolarization of light emitted from the

I in ear polar izer interf ere nce filter
or mo noch rometer -~~=

beam passing through the carbon foil.
Photons are observed in a directionPM

perpendicular to the beam axis and to
the normal of the tilted foil.

References1)
2)

H.G. Berry, L.J. Curtis, D.G. Ellis, and R.M. Schectman: Phys. Rev. Lett., 32, 751 (1974).
H.J. Andrii, H.J. Plohn, A. Gaupp, and R. Frohling: Z. Phys., A281 , 15 (1977).

87

III-2-13.

lattice location of Sn Atoms Implanted into AI Crystals
as Investigated by Means of Channeling Method

E. Vagi, A. Koyama, H. Sakairi, and R.R. Hasiguti *Some kinds of impurity atoms implanted into Al crystals occupy interstitial sites. Therefore
the investigation on the lattice locations of such impurities will give information on the interstitialsites or the configurations of interstitials in an Al crystal. In the present study, the lattice locationof Sn atoms implanted into Al crystals is investigated by means of channeling method. The
implantation was carried out at room temperature and at 150 kV with various doses. Axial
channeling effect was investigated with respect to <100>, <110>, and <Ill> axes by means ofbackscattering with 1 MeV He+ ions. Figure 1 shows the normalized backscattering yields fromAl and Sn atoms as a function of the angle between the incident beam direction and the < 110>
crystal axis for a specimen implanted with the dose of 1 X 10 14 Sn/ cm 2 . The back scattering
yield from Sn atoms gives a shallower and narrower dip than the AI-dip. In the < 111 > angularscan, it gives also a narrower dip than the AI-dip. These results suggest that the Sn atoms occupy
interstitial sites which are different from those of Sn atoms in Al crystals implanted with thehigher dose, 1 X 10 16 Sn/cm 2 , 1) and also implanted Ni atoms in Al crystals. 2 ) A detailed
investigation is in progress.
<110)
0

1.0

AI

• Sn

-0
Q3

->tID

c

~
C\l

<..)
(f)

-0

(l)

-!::::!

m

0.5

Fig. 1.

E
0z

Normalized backscattering

yields from Al and implanted Sn

o~

__

-3

~

-2

____

~

-1

__

~

____

~

____

0
Angle (degrees )

~

2

__

~

__

3

~

4

atoms as a function of the angle
between the incident beam direction
and the < 110 > crystal axis. The
implantation dose is 1 X 10 14 Sn/cm 2 .

References
1)
2)

A. Koyama and H. Sakairi: IPCR Cyclotron Progr. Rep., 11, 92 (1979).
E. Vagi, A. Koyama, H. Sakairi, M. Iwaki, and R.R. Hasiguti: 1. Phys. Soc. Japan, 50, 873(1981).

* The Science University of Tokyo.

88III -2- 1 4.

Secondary Electron Em ission from Metal Targets
under Heavy-Ion Bombardment

A. Koyama, T. Shikata,
H. Sakairi, and E. Yagi

The secondary electron emission coefficients 'Y for in-situ vacuum deposited AI , Cu , Ag , and Au targets aremeasured under bombardment with He 2+ , C4 +, C6 + , N4 + " N 5 +, N7 +, 0 5 + , and 0 8 + ions in the energy region of
4.5 - 8 MeV /amu . Ion currents are 0.5 - 1 nA. The experimental apparatus and conditions were described in
our previous reports. 1 ),2)

Figure 1 shows the energy dependences of 'Y for Al and Ag targets under bombardment with N4 +, N 5 + ,and N 7 + ions. It shows that the energy dependence of 'Y is rather insensitive to the variation of the projectile
charge state. Tlle energy dependences of 'Y under bombardment with these ions are expressed as,'Y 0: E -0.36, for AI ,'Y 0: E -0.45 , for Ag ,}(1)

where E is the incident energy of these ions in MeV /amu .
The decrease of'Y with E is gentler than that of the electronic stopping power S. Thus 'Y/S increases withincident ion energy, which is the same as the experimental result by Oda and Lyman. 3 )Table I shows values of the ratio R(zl' c; Z2) == 'Y(Zl' c; Z2)/'Y(zl ' zl; Z2)' where 'Y(zl' c; Z2) is for a targetof atomic number Z2 under bombardment with a partially stripped projectile of atomic number Zl and electriccharge c, and 'Y(zl' c; Z2) for the same target under bombardment with a fully -stripped one of the same atomic
number zl' The first column is for the specification of the projectile system used for obtaining the value ofR(zl' c; Z2). The second column shows the values of R for the targets used. The third column shows the values

89

Table 1.

Dependence of 'Y on the projectile charge state. Zl is the atomic number of the projectile and cis its electric charge. N is the number of electrons bound to the projectile and is equal to zl-c.

p

R(ZI' c; Z2)
Al
C4 + /C 6 +0.71

N4 + /N 7 +0.75

N 5 + /N 7 +0.82

0 5 + /0 8 +

0.74

Cu

Au

Ag

0.44

0.72

0.7 8

0.33

0.66

0.72

0.90

0.51

0.76

0.80

0.84

0.39

0.70

0.74

0.79
0.83

Z 2 + c 2 Z 2 + c 2 + 2N
I
P
1
2z 2
2z 2
1
1

c2
Z2
I

0.89

0.86

2 2
The fourth column shows the values of (z 2 + c2 )/2z12. R(ZI' c; Z2) is much larger than C /z 1 , but
12
2
is nearly equal to (Z1 2 + c2 )/2z12. Thus, 'Y(zl' c; Z2) is nearly proportional to (zl + c )/2.

of c 2/z 2.
I

Figure 2 shows R(zl' c; Z2) as a function of target atomic number Z2'

The Z2 -dependence of R(zl' c; Z2)

is expressed byR(z I' c·, Z 2 ) = AZ 2
0.1
'

(2)

where A is independent of Z2 and is equal to 0.6 in the case of the ratio of 'Y for N4 + ions to that for N 7 + ions.
According to Schou,3) 'Y is nearly proportional to S at the target surface for the projectile. If the ratio 'Y/S
is independent of the charge state of projectiles, R(ZI' c; Z2) is equal to the ratio of the square of the effective
charge at the surface of the target for the partially stripped projectile, Zeff2(zl' c; Z2)' to that for the fully stripped
one, Zef?(zl' Zl; Z). The square of the effective charge for a partially stripped ion was theoretically given by Kim
and Cheng. 4 ) By refering to this theory, Zef?(zl' c; Z2) is deduced semiempirically from the values of R(zl' c; Z2)
and is expressed in terms of Zl' C and Z2' as follows:Z
where N2(Z c· Z ) = (z 2 + c2 )/2 + N + aN Z 2/3
eff I"
2
1
P
P 2 '

(3)

is the number of the bound electrons and is equal to Z - c, and a is the numerical factor and is equal toI22+ N p)/2z 1 2. It agrees well with thevalue of R(zl' c; Z2)' The Z2 -dependence of R originates from the third tlrm on the right hand side of Eqn. (3).

p0.16 for N 4 + ions. The fifth column of Table 1 shows the value of (zl +co N4 +/ N 7 +X

C4+/ C 6 +Fig. 2.

/::, 0 5 +/ 0 8 +o'Y(ZI' c; Z) / 'Y(ZI ' Zl ; Z2) on target atomic
number Z2' where 'Y(ZI' c; Z2) is for a targetof atomic number Z2 under bombardment with

N5 +/ N 7 +~ 1.0!

~~! ~~=--~-~~~~

II~

0,5 L-______~1_ _____- L_ _~'_ _~~'~'~
__
10

20

40

Target atomic number Z2

Dependence of R(zl ' c; Z) ==60

80

a partially stripped projectile of atomic number
Zl and electric charge c, and 'Y(zl ' Zl ; Z2) isthat for the same target under bombardmentwith a fully stripped projectile of the sameatomic number zl .

Incident energy of the

projectiles is 6.2 MeV /amu.

90

References
1)
2)
3)
4)

A. Koyama, T. Shikata, H. Sakairi, and E. Yagi: Jpn. 1. Appl. Phys., 20,65 (1981).
A. Koyama, T . Shikata, and H. Sakairi: IPCR Cyclotron Progr. Rep., 11,83 (1979).
N. Oda and 1. T. Lyman: Radiat. Res.,.2: Suppl., p. 20 (1967).
Y. K. Kim and K. Cheng: Phys. Rev., A 22,61 (1980).

91

III-2-15.

Distributions of the Hyperfine Magnetic Field at
119

Sn ( -119Sb) on the Surfaces of a-Fe20 3

T. Okada, H. Sekizawa, F. Ambe, and S. Ambe

The present work aims to utilize emission Mossbauer measurement of the supertransferred
hyperfine (hereafter abbreviated as STHF) magnetic fields in studying the chemical state of very
dilute antimony ions "adsorbed" onto the surfaces of oxides. In the actual work, the techniqueof emission Mossbauer spectroscopy of 119Sn, with 119Sb as the source nuclide, has been applied tothe study of carrier-free pentavalent antimony ions adsorbed on the surfaces of corundum typeantiferromagnetic oxide, a-Fe 2 03 (Neel temperature: 950 K).

In the measurement, Mossbauer
analysis was made on the 23.8 keY ')'-rays emitted by 119Sn nuclei in the first excited state ( 119 Sn*,half life : 17.8 ns) arising from 119Sb (half life: 38.0 h) by the Ee decay.
The nature of the chemical bonds formed by 119Sb ions on the oxide surfaces is explicitly
reflected in the emission spectra as the STHF interaction of 119Sn* (~119Sb) with its magnetic
environment.
Experimental procedures and a part of the experimental results have already been reported ina previous report. 1 ) The present report is concerned with the results of subsequent detailed
research.
Emission Mossbauer spectra of the "as adsorbed" (A) and 2 h heat-treated (B to E)
a-Fe 2 0 3 - 119Sb5+ specimens at liquid nitrogen temperature are shown in Fig. 1. The
temperatures of heat treatments were 200°C (B), 400 0 e (e), 500 0 e (D), and 700°C (E). The
spectrum of a specimen (F), obtained by coprecipitating carrier-free 119Sb5+ with Fe 3 + from an0aqueous solution with subsequent calcination in air at 700 e for 2 h, is also given in Fig. 1.
Even in the "as adsorbed" specimen (Fig. 1 A), there can be seen a remarkably broadened
emission line, which transforms gradually into the six-line magnetic hyperfine pattern (B - E) withelevation of temperature of the isochronal heat treatment. We attribute the observed broadening
and splitting to magnetic interaction of the 119Sn (~119Sb) ions with the magnetically ordered Fe 3 +ions of the a-Fe 2 0 3 substrate.

The distributions of hyperfine magnetic fields (H hf ) obtained byanalyzing the spectra by means of the method of Hesse 2 ) are shown in Fig. 2.

The spectra werealso analyzed by the method of Window 3 ) and the results were in good agreement with those by
the method of Hesse.

Measurements at room temperature gave distributions of Hhf similar intrend to those at liquid nitrogen temperature.

This similarity is compatible with the fact that the

Neel temperature of a-Fe 2 0 3 (950 K) is much higher than the above two temperatures ofmeasurement
The other parameters were also derived from Mossbauer emission spectra. From the valuesof isomer shift it is certain that the 119Sn ions resulting from 119Sb5+ were tetravalent in all thea-Fe 2 0 3 specimens.

The isomer shifts showed a temperature dependence expected from thesecond order Doppler shift.

The ratios of the adsorption areas of the spectra at room temperature

to that at liquid nitrogen temperature were in the range of 0.7 - 0.8 in the coprecipitated (F), in
the heat-treated (B to E), and even in the "as adsorbed" specimens (A). It means that the92

adsorbed 119Sb ions have unexpectedly high Debye temperatures.
As can be seen in Fig. 2 A , no peak was observed explicity at Hh f == 0 in the hyperfine field
distribution of nominally diamagnetic 119Sn4+ (+- 119 Sb) ions in the "as adsorbed" specimen.
In order to analyze the effect of heat treatment, the ranges of Hh f in Fig . 2 were divided
equally into three regions called I, II , and III respectively in order to intensity of the fields.
Variations of weights of the regions are plotted against the heating temperature in Fig. 3. The
weight of region I which is dominant before the heat treatment (A) decreases monotonically withthe heating h~mperature.

Weight of region II increases slowly up to about 500°C (D) andA

B
Reg ion Re gionI

Reg ion

II

III

c
c

.<2
(j)
(j)

E
c

(j)

cu

~

E

4

2

-1 4

o

+ 14

o

temperature.

100

150

Fi eld ( KOe)

Veloc it y ( mm/ s)

Fig. 1.
Mossbauer spectra of the
119
a-Fe 2 03 _ Sb at liquid nitrogen

50

Fig. 2. The distributions of
the hyperfine magnetic fields
obtained by analyzing thespectra of a-Fe 2 03 _119 Sb bymeans of the method ofHesse.

93~*"a'100

o

-.-4

~

o

80

~

. . --'tj

&: 60
...'

,"

IT

~"
.,.'
...
.

.

'\

,
.
/
\

~

I

Fig. 3.

•

o

/~

,

\

/

o

!

1m

.

... / \
I

400

,
...,

'-.1 ••---I._ _...I....-_~......

800

1200
(OC)
Anneal ing Temperature
Dependence of the relative fractionof the distribution on the heating temperature.
decreases abruptly above it. The decrease in the weight of region II is accompanied with rapid
increase in the weight of region III, which dominated at the heating temperature of 700°C (E).
The distribution of specimen (E) is almost equal to that of the coprecipitated specimen (F), whichmeans that the adsorbed 119Sb ions diffused into the substrate deep enough by 2 h heat treatment
at 700°C so as to make the daughter 119Sn nuclei to feel the same hyperfine magnetic fields as theones on the daughter 119Sn of the coprecipitated 119Sb ions. These variations of hyperfine field
distribution by heat treatment were interpreted in terms of the STHF interactions on 119 Sn 4 +(+- 119 Sb) ions diffused into various sites of the surface structure of ~-Fe2
The detailed.

°

3

discussion on the experimental results will be published elsewhere.
A similar investigation of Cr 2 0 3 _ 119 Sb is in progress.

References
1)
2)

T. Okada, H. Sekizawa, F. Ambe, and S. Ambe: IPCR Cyclotron Progr. Rep., !±, 86 (1980).
J. Hesse and A. Rubartsch: J. Phys. E: Sci. Instrum., 7, ~26 (1974).

3)

B. Window: ibid., i, 401 (1971).

94

III -2-16.

Angular Correlation Measurements on Nb-Mo System

N. Shiotani, T. Okada, H. Sekizawa, and T. Nakamichi

Niobium and molybdenum have nearly the same electronic band structure, especially at andbelow the Fermi level. The Fermi level is higher in Mo than in Nb because of the extra valence
electron per atom. Consequently, measurements of the angular correlation of positron annihilation
radiation in a series of binary Nb-Mo alloys should provide information on how the addition of delectrons to the unfilled d band changes the geometry of the Fermi surfaces.
Single crystals of Nb 8o M0 2o and NbsoMoso were grown by zone melting in an argon arc
furnace. The angular correlation curves were measured by a parallel slit system at room
temperature. The results are shown in Fig. lea) - l(c). The effects of alloying can be seen inchanges of fine structures of the observed angular correlation curves.
(b)

(a)

Nb- Mo TJ, along [100 J

Nb- Mo p, along [1 1OJ

Vl

5Nbso Moso

Nb

o

2.0

Nb

3.0

p, in atomic mits

o

1.0

2.0
P,

30

in at omiC uni ts(c )Nb- Mo p, al ong [ 111 J

Vl

5

Fig. 1.
Angular correlation curves
N(pz) of Nb, Nb 80 M0 2o ' and NbsoMoso'(a) Pz along [100] ,(b) Pz along [110],

Nb;o Mosoand (c) Pz along [111] .
Nb

G

20

1.0
P,

in atomic uni ts

3.0

95

1II-2-17.

Creep Properties in Helium-injected SUS 316
andii-Precipitation Strengthened Alloy

N. Yamamoto,* H. Shiraishi, H. Yoshida,*
H. Kamitsubo, 1. Kohno, and T. Shikata

Helium generated by (n, a) reactions has long been identified as the main cause of the neutron irradiation
embrittlement of alloys used in fast breeder and future fusion reactors.

The presently accepted mechanism is that

helium bubbles form and weaken the grain boundary of the material and thus the intergranular fracture easily
occurs. Among the experimental methods to study this phenomenon, helium injection by using an accelerator isconventional because the required amount of helium can be introduced into the specimen in a short time period,
and the induced radioactivity of the specimen is low. In the present study, we took this method, and effects ofhelium on creep properties were studied for SSU 316 and 'r" -precipitation strengthened alloy.
Results of chemical analysis of the alloys used are presented in Table 1. SUS 316 is a typical fast breeder
structural material, and 7818 alloy is a ,,/" Ni3 Nb precipitation strengthened alloy which has exhibited excellent
tensile properties after helium injection. I)

The virgin raw materials were melted using a vacuum induction furnace,

and 17 kg ingots were fabricated. Then, these ingots were hot forged and hot rolled at 1200°C. Finally, 0.2 mm
thick plates were prepared by repeating cold rolling and intermediate annealing (l050°C, 30 min). Creep test
Table 1.

Chemical composition of used samples. (wt %)

Alloy

C

Ni

Cr

Mo

SUS 316

0.043

13.9

16.1

2.50

7818

0.024

39.9

14.7

3.03

Ti

0.31

Nb

2.96

Si

Mn

B

0.44

1.42

0.00060.48

0.19

0.0048

50
40
30
--..

NE
E

20

'--.

tID

..::.:.

~

~

10

•

(f)

~
~

alloy

He conc.
0
SUS316lOat. ppm
07818
10at. ppm

0.
::::J

0::

650 °C 700 °C

-

•

0

•

. .

6.

\l

0.1
Rupture time (h)Creep rupture curves for SUS 316 and 7818 alloy in which helium
Fig. 1.
was uninjected and injected to 10 at. ppm.

* National Research Institute of Metals.

96

Table 2.

Alloy

Creep rupture properties of helium injected SUS 316 and 7818 alloy-.

Test temp.

He conc.

StressCC)(at. ppm)(kg/mm2)

0
SUS 316

700

{

10

0
700

{

10
7818

0
650

{

10

specimens were die-stamped out from these specimens.

Rupturetime(h)Ruptureelong.
(%)

23.0

0.7

49.7

15.1

33.2

57.2

13.3

73.4

61.4

12.5

134.7

55.2

11.0

364.2

59.5

9.8

724.2

53.3

11.0

113.5

17.7

9.7

185.8

12.7

8.0

552.5

14.5

30.0

0.4

28.6

28.0

29.9

26.1

26.5

94.4

24.3

22.5

265.0

18.2

15.4

1128.7

11.8

22.5

5.2

6.4

14.5

137.6

1.8

40.1

0.2

29.8

38.0

1.0

30.2

36.0

0.5

35.0

35.1

114.9

31.6

34.5

135.4

41.8

34.0

253.4

31.1

32.5

387.8

28.2

29.0

1134.5

20.7

32.5

38.4

0.8

28.0

225.5

4 .7

26.6

202.6

2.9

The dimension of gauge section was 10 mm long, 4 mm

wide , and 0.2 mm thick.

Then, the specimens were solution treated for 30 min at 1050°C for SUS 316 and at

1100°C for 7818 alloy.

This treatment resulted in the mean grain size of 46 J.1m and 69 J.1m , respectively.

Helium was injected at constant high temperature (650°C or 700°C), using the cyclotron.
content of each specimen was about 10 at . ppm.

The injected helium

The creep tests were carried out on the uninjected and injected

specimens at the same temperature with that for helium injection in flowing Ar gas of 99.999 % up purity. The
elongation at rupture was determined after testing by using a profile projector. The fracture surface of ruptured
specimens was examined by a scanning electron microscope.

Transmission electron microscope examinations on

the fractured specimens were made mainly to study the morphology of helium bubbles.
The results of creep tests are shown in Table 2. As illustrated in Fig. 1, the decrease of the creep rupture
strength by helium in 7818 alloy was much higher than that in SUS 316 at 700°C, but appreciably improved at

97

650°C test.

The rupture elongation was greatly reduced after injection, although the extent of the deterioration

varied between two alloys.

Fractographs by SEM revealed that while the fracture occured in ductile mode in

helium free reference materials, the helium injected specimens showed an intergranular brittle fashion, and as
illustrated in Fig. 2(a), large helium bubbles were found out at grain boundaries in the creep ruptured specimens.
These observations show the direct evidence of helium embrittlement.

On the other hand, Fig. 2(b) shows that

small helium bubbles were trapped at NbC precipitates in the matrix.

This result implies that the helium

embrittlement can be reduced if it is possible to trap more helium bubbles in the matrix by adjusting the size anddistribution of NbC precipitates.

( b)1000 A

Fig. 2.

Transmission electron micrographs of the 10 at. ppm helium injected and creep ruptured

7818 alloy.

Test temperature: 700° C, creep stress: 22.5 kg/mm2, rupture time: 5.2 h.

(a) Large

helium bubbles in a grain boundary; (b) small helium bubbles at the NbC precipitate in the matrix.

Reference1)

H. Shiraishi, H. Shinno, N. Yamamoto, H. Yoshida, H. Kamitsubo, I. Kohno, and T. Shikata:
Progr. Rep.,!±, 79 (1980).

IPCR Cyclotron

98

III-2-18.

Channeling in Argon-Implanted Diamond

M. Iwaki and H. Sakairi

A study has been made of radiation damage and depth profile of argon implanted diamond bymeans of the 1 MeV 4He channeling technique with the use of the Tandetron.
Substrate used were natural and colorless diamonds with the surface nearly parallel to the(111) plane. Before ion implantation, the surfaces of all specimens were mirror-polished andsputtered by 5 keV Ar+ ion beams coming at an angle of 75° from the normal.
was performed with the dose of 1 X 10 16
The beam current density was about

Ar/cm 2

1 J.1A/cm 2 .

Ion implantation

at the energy of 150 keV at ""'2 X 10- 6 Torr.
The target temperature during ion implantationrose from room temperature to about one hundred degrees of centigrade by the heating effect of
the ion beam itself. The ion beam was sent in the direction deviating by a few degrees from the< Ill> crystal axis in order to reduce the deep penetration of implanted argon by channeling.
Channeling measurements (Rutherford backscattering) were done by using 1 MeV 4He+ withthe fluence of 5 J1Q. Backscattered particles at an angle of 150° were detected and analyzed bya solid state detector and conventional electronics. The samples were mounted on a 3 axis
goniometer in a target chamber, which was at a pressure below 5 X 10- 6 Torr.
Figures 1 and 2 show the < III > aligned and random spectra observed for argon implanted
diamond. The leading edge of the diamond target is at channel number 442 (located at harfheight) and the energy edge of argon at the diamond surface at channel number 1145. Theenergies at channel numbers 442 and 1145 are 0.273 and 0.687 MeV, respectively.

The spectra

obtained for backscattered particles from argon implanted in diamond do not exhibit any
difference between random and channeling spectra as shown in Fig. 1. Moreover, as shown in50- Random0 <111>

40

30
~
C

::J
0

0

20

FWHM

10

Surface

1

~~~

1200

800
Channel number

Random (.) and < III > aligned (0 ) spectra of argon
Fig. 1.
implanted in diamond.

99500.---------------------------------------------------~

•••

•
• ••

400r

300
IJ)

C

:J

o

u 200

•o

100

.0

•

o

I

1

I

200

300

400

Channel numb er

Random (.) and < III > aligned (0 ) spectra of diamond
implanted with argon.
Fig. 2.

Fig. 2, the channeling spectrum overlaps with the random spectrum at channel number above 285.
These results display that argon implantation in diamond produces the amorphous layer near its
surface, where implanted argon atoms are located at random sites.
The depth profile of implanted argon and the thickness of the amorphous layer can beobtained from Figs. 1 and 2 by using a zero-order analysis. The solid line in Fig. 1 indicates thedepth distribution predicted by the range theory. The depth corresponding to the peak obtained
from the spectra is about 770 A , which is in good agreement with the predicted range of 772 A.
The standard deviation calculated from the FWHM of the spectra is about 220 A, which is a little
larger than the predicted value of 190 A. Because the FWHM of the spectra contains not only
the depth distribution of the argon, but also the energy resolution of the backscattering systemand the energy straggling of the 4He ions, the calculated standard deviation may be a little smaller
and close to the predicted value. The results suggest that the depth profile of argon implanted indiamond can be predicted by the range theory.
The thickness of the amorphous layer is, if it is assumed to be the region from 262 to 442
channels as indicated in the figure, about 1340 A, which is 1.8 times as large as the averageproj~cted range.

The amorphous layer of the diamond surface produced by argon implantation
exhibited the electrical conductivity, which was measured by means of a four point probe method.

The sheet resistivity of the specimen was about 170 n/ cm 2 .

If the conductivity is assumed to be
attributed to the amorphous layer, the resistivity is 170 X 1340 X 10- 8 = 2.3 X 10- 3 n·cm,
which is almost the same as that of the glassy carbon (produced by Tokai Carbon Company Ltd.).
It is concluded that the average predicted range and standard deviation of argon implanted indiamond are in fairly good agreement with those predicted by the range theory. By argon
implantation with 1 X 10 16 ions/cm 2 at 150 keY, the surface layer of diamond becomes amorphousand induces electrical conductivity. The resistivity of the amorphous layer is almost the same asthat of the glassy carbon on the market.

100

III -2-19.

Ion Beam Mixing of the Aluminum
Film-Iron Substrate Interface

M. Iwaki and K. Takahashi

In the field of modification of the near-surface region of metals by ion implantation,
considerable attention has been directed toward the change of physical and chemical properties ofthe metal, such as improvements of friction, wear and corrosion.

Recently, the doping of thegiven species in metals has been carried out not only by direct implantation but also by the ion
beam mixing.

The doping technique by mixing is as follows: One deposits a thin film of thegiven species on the substrate and then intermix the film and substrate by ion bombardment ofenergetic ions which penetrate through the film-substrate interface.

In this report, the effect ofion implantation into aluminum deposited iron plates is investigated on the depth profile ofaluminum and iron, and the corrosion behavior.
The iron substrates used were mirror-polished by buffing wheel and ultrasonically cleaned intrichloroethylene, and moreover sputtered by 5 ke V Ar+ beams at an angle of 75° from the normal
at a pressure of ""'2 X 10- 6 Torr. Aluminum thin films a hundred angstroms thick, were preparedon the iron substrates by sputter coating at room temperature by using IMMI-V (Commonwealth
Scientific Co. Ltd.) at ""'2 X 10- 6 Torr.

In this proce~s, several iron substrates were placed insuch a way as to make an angle of 30° with an aluminum plate and the aluminum was sputtered at
an angle of 60° from the incidence of 5 ke V Ar+ beams. The iron targets were rotated at random
so that sputtered aluminum can be deposited on the iron surface uniformly.
Ion implantation with oxygen and argon was performed with the dose of 1 X 10 16 /cm 2 at
the energy of 150 ke V at ""'2 X 10- 6 Torr by using the RIKEN 200 kV Low Current Implanter.
The conditions of the dose and energy were selected in such a way so as to reduce the thicknessof material removed by sputtering during ion implantation and for most implanted atoms topenetrate into the deeper region than the film-substrate interface.

The target temperature during

ion implantation rose to a temperature slightly higher than room temperature by the heating effectof the ion beam itself.
Depth profiles of aluminum and iron were measured by means of secondary ion mass analysis,
which was carried out by Ion Beam Surface Mass Analyzer (lSMA, produced by Commonwealth
Scientific Co. Ltd.).

ISMA includes the facility to produce primary bombardment ions of bothactive oxygen and inert argon, a quadrupole mass analyzer and a provision for automaticallyrecording individual masses for depth profiling.

The sputtering removal rates used for measuring

the depth profiles were ""'10 A/min for aluminum and ""'20 A/min for iron with the primary
oxygen ion energy of 7 - 8 ke V at a sputtering angle of 45° .
Figure I shows the depth profiles of aluminum and iron in unimplanted (as-coated), oxygen
implanted and argon implanted specimens.

In the unimplanted specimen, it seems that aluminum

has invaded the iron substrate, but no sharp interface appeared.

This may have been caused by

the unexpected islands of the deposited thin films, the roughness of the based iron plates and the

101

I

I

I

rAJ/' ~ ......... A
c:=g600 •!:;.!:;.
Fe

100 -

~?

A.~

..
c

0

o
~

• 0

10 I- •

0
!:;.

~

•~

c
G)

u

c

0

u

• •~

G)

LL
c:>(:l

-

0

0

!:;.

0
!:;.

~ AI

«

0

0

6
6

0

11-

0

0

-

6

0

Fig. 1.

0Depth profiles of aluminum and ironin unimplanted (0 , .), oxygen implanted (0, .) and
I

o

I

10

20

30

40

argon implanted (1"', ... ) specimens, which are pureiron plates coated with aluminum.

50

Sputtering t ime (m i n )30.-----------------------------~

Fe

'"E
u

~

«

E

:: 20 -

•

(J)

c

G)

•

•

•

•

•••••••••••••

u

•

c
~
:::J
U

-'1.

~
a.

lO -

Fig. 2.

.~uocRelationship between anodic

peak current density and number of«potential sweep cycles with un-coated(.) as-coated (0 ) and oxygen (6 ) or argonoNumber of cyc les

ion beam mixing during depth profiling.

(... ) implanted specimens after coatingaluminum
By ion implantation through the thin film, especially byargon implantation, it is obvious that iron moves into the aluminum thin film and aluminum
penetrates into the iron substrate, as compared with the depth profile of the unimplanted specimen.
The results show that the ion beam mixing of the thin film-substrate interface can occur by ion
implantation through the interface.
The corrosion behavior of these specimens was investigated by means of the cyclic voltammetry
in 0.5 M acetate buffer solution (pH 5.0).

The cell construction and the instrument for theexperiment were given in detail in Ref. 1.

Cyclic-voltamograms show the anodic dissolution current

peak and the depressed current region with passivation. The anodic peak current density
corresponds to the reactivity of the anodic dissolution reaction of the metal surface . Figure 2

102

shows the relationship between anodic peak current density and number of potential sweep cycles,
which shows the change of reactivity of the surface with repeat of the potential sweep cycles. The
peak current density of iron is relatively high and that of aluminum is very low. By depositingaluminum on iron the anodic peak current density becomes low, and even lower by subsequention implantation. The results show that the ion beam mixing is an important technique for the
improvement of corrosion.
In conclusion, ion implantation through the deposited thin film results in making the sharp
interface of the thin film-substrate dispersed and improving the corrosion resistance.

Reference
1)

K. Takahashi, Y. Okabe, and M. Iwaki: Nucl. Instr. and Methods, 182,1009 (1981).

103

III -3.

Radiochemistry and Nuclear Chemistry1.

Charged Particle Activation Analysis of
Semiconductor Materials

T. Nozaki, Y. Terai, H. Emori,* M. Takeya,*T. Masui,** S. Muraoka,** M. Watanabe,*** and T. Usami***Utilization of charged particle activation analysis has been continued for the study on carbon, nitrogen andoxygen in semiconductor materials in collaboration with the following companies: Mitsubishi Metals Co., Shinetsu
Semiconductor Co., Toshiba Electric Co. , and Hitachi Ltd. Oxygen content of gallium arsenide crystals wasstudied in correlation with their preparation conditions, and nitrogen in silicon was analyzed in order to determine
the calibration curve for its infrared spectrophotometry and to examine nitrogen contamination into silicon
crystals pulled from crucibles covered with silicon nitride. Charged particle activation analysis was also used foroxygen depth profiling and for surface oxygen analysis ; these are presented as separate reports in this volume.
Gallium arsenide is one of the most difficult matrices in oxygen analysis by activation with the 160eHe,p )18p
reaction , because its oxygen content is usually very low and because high activities of radio-germanium, radio-arsenic,
radio-selenium and radio-bromine are formed from the matrix itself. We have developed a satisfactory method ofseparating the 18p from various matrices, converting the 18p into KB 18 p 4 precipitate. I) By this method, as low
as a few wt ppb of oxygen in semiconductor GaAs has been determined successfully.

Gallium arsenide

crystals prepared from its melt under various conditions were analyzed in order to get information about (1) oxygen
concentration range for commercial GaAs crystals, (2) dependence of oxygen concentration on the preparation
methods and dopants , (3) effective distribution coefficient of oxygen between solid and liquid GaAs , and (4)possibility of oxygen doping to the crystal by the addition of Ga 2 0 3 to the melt.
Oxygen concentration in semi-insulating GaAs bulk grown both by the liqUid encapsulated Czochralski process
and by the holizontal Bridgeman method was found to vary from 3 wt ppb to 18 wt ppb.

No oxygen level lower

than these has ever been reported for any other high-purity substance and for GaAs itself.

The low oxygen

content is probably due to the ease of oxygen escape by vaporization as arsenic oxide and, in the Czochralski
process, by extraction into coexisting B2 0 3 melt as oxides of silicon and chromium which were added as dopants.
No marked difference in oxygen content was found in chromium-doped crystals due to the difference in the
crystal-formation method .

Silicon-doped crystal did not exhibit any elevated oxygen concentration.

Effective

distribution coefficient of oxygen between solid and liquid GaAs was estimated to be about 2 from the change ofoxygen content of the crystal along with the solidified fraction in the encapsulated Czochralski process.

Themeasurement of oxygen levels at three different portions of holizontal Bridgeman crystals formed from Ga 2 03 -added
GaAs melt has indicated that intentional oxygen doping to the GaAs single crystal is quite inefficient. More detailsof this study will be published. 2 )Nitrogen in silicon is known to exhibit sharp infrared absorption peaks at 963 cm- l and 764 cm- l .

In heattreatment , less dislocation has been shown to be formed in nitrogen-doped float-zone silicon than in ordinary
Czochralski silicon. 3) We previously determined the phase diagramme of the N-Si system in the extremely low
nitrogen concentration range 4) and recently the calibration curve for infrared spectrophotometry of nitrogen insilicon by charged particle activation with the 14N(p, a)l1C reaction.

In our recent experiments , the previous

procedure has been used with the following modifications: 5) in the chemical separation of the 11 C, a larger amountof Na 2 C0 3 carrier is added and converted into the counting form of Li2 C0 3 by precipitation from a methanolic
solution.

*
**
***

By this modification, the interference of non-radioactive carbonate contamination can be made negligible

Mitsubishi Metals Co.
Shinetsu Semiconductor Co.
Toshiba Electric Co.

104

and the carrier recovery can be determined reliably by simple weighing.

Various silicon samples with and without

nitrogen doping were prepared and subjected to the infrared absorption measurement and act ivation analysis.
calibration curve thus obtained is shown in Fig. 1.
reliability of the calibration curve.

The

Further work is under progress with more care to elevate theUse of a crucible covered with silicon nitride is thought to be effective fo r the preparation of Czochralski
silicon with reduced oxygen contents.6 )Nitrogen contents of silicon crystals prepared from melts in such crucibles

under slightly different conditions have been measured by the activation analysis.
have often been found. This work will be continued further.

Contents of about 100 wt ppb

Nitrogen concentration ( wt ppb )10 ~____3~0_____6TO_____9~0~

48----:--

'"I

,.

3

E
u

~
0.

I

0
.........

E

6

cu

(f)

f------+---'

~
f

C

OJ

Q
OJ

0

u

c
Q

0

.........

4

Q

0
(f)

E

u

2

OJ

u

c
cu

-D

0
(f)

~

-D

<{

2

0

i

-D

~/

3.0
9.0
6.0
Nitrogen concentration ( 10 15 at/cm 3 )

-2

<{

0

Calibration curve for infrared
Fig. 1.
spectrophotometry of nitroge n in silicon.

References
1)
2)

T. Nozaki: 1. Radioanal. Chem.(in press).
H. Emori, M. Umehara, M. Takeya, Y. Terai, and T. Nozaki: Proc. 1981 Intern. Symp. Gallium Arsenide

3)

and Related Compo (in press).
T. Abe, K. Kikuchi , S. Shirai , and S. Muraoka: Semiconductor Silicon 1981, (Ed. by H.R. Huff et al.) ,4)

Electrochem. Soc., Pennington , p. 54 , (1981).
Y. Yatsurugi, N. Akiyama, Y. Endo , and T. Nozaki: 1. Electrochem. Soc., 120 , 975 (1973).

5)
6)

T. Nozaki, Y. Yatsurugi , and N. Akiyama: 1. Radioanal. Chern.,.±. 87 (1970).
M. Watanabe , T. Usami, H. Muraoka, Y. Imanishi , and H. Nagashima: Semiconductor Silicon , (Ed. by H.R.
Huff et al.), Electrochem. Soc. , Pennington , p. 126 (1981).

105

111-3-2.

Charged Particle Activation Analysis for Surface
Oxygen on Silicon and Aluminum

T. Nozaki and M. Iwamoto

Although most methods of surface analysis are applicable only to sample in a high vacuum, it
is more important to study surfaces under atmospheric pressure, particularly in the analysis ofsurface oxygen.

Charged particle activation analysis is useful for this purpose, by the use of asuitable target assembly.
interval.

We initiated this study in 1977 1) and have continued it after some

The apparatus we used is shown in Fig. 1.

The sample in a form of two plates in intimatecontact with each other is placed on a water-cooled target holder in a bombardment vessel, which
can be evacuated by oil-free pumps. The reaction of 160eHe, p)18F has been adopted forradioactivation, and the incident particle energy is so adjusted as to give the maximum cross section
for the reaction on the inside surface of the sample plates.
We analyzed high-purity silicon and aluminum.

Silicon wafers for the sample were pretreatedwith a mixture of HF-HN0 3 (1: 3) at room temperature, washed in pure water with the aid of
ultrasonic waves and dried.

Aluminum wafers were pretreated with acetone or a mixture of

H3 PO 4 - H2 SO 4 (1: 3) at 95°C in the same manner.

Two of these wafers were set in thebombardment vessel and bombarded with charged particles (1 ""'2 JiA, 20 min) under three
conditions: atmospheric pressure , about 10 Pa and 10- 3 Pa.
Only the wafer forward to the incident particle direction was taken for the measurement of
the 18F activity, because 18F produced in the backward wafer is known to be pushed into theforward wafer almost completely.2)
The inside surface of about 5 mg cm- 2 thickness was ground off from the bombarded silicon,
and transferred into a polyethylene tube for activity measurement. The annihilation radiation wasmeasured with a well-type scintillation crystal and a single channel analyzer, and the decay wasfollowed. Each 'of the aluminum sample after the bombardment, was sandwiched betweea two
card plates.

Annihilation radiation from the sandwich was then measured with a Ge(Li) detector

and a multi-channel analyzer. As an activation standard, a stack of five or six Mylar films werebombarded and the 18F activity in each films was measured under the same conditions as thosesample, to give an apparent activation curve. The results of the analysis are shown in Table 1.
Sample Holder
SampleFig. 1.

Apparatus for radioactivation.

106

Table l.

Surface oxygen quantities (/lg cm - 2) for different
environmental pressures.
(Mean values for repeated measurements, with thenumbers of repetitions indicated in the parentheses)
Al

SampleSi

Pressure~

HF-HN0 3

Atmospheric

0.7

(8)

7

(4)

3

( I )

(Pa)

0.2

(11 )

6

(2)

2

( 1)

about 10- 3 (Pa)

0.09

(3)

4

(2)

0.4

(2)

about 10

AcetoneH3 P0 4 -H2 S04

References
1)
2)

T. Nozaki and M. Iwamoto: IPCR Cyclotron Progr. Rep., 1L 116 (1977).
T. Nozaki, M. Iwamoto, and K. Usami: ibid.,.!±, 93 (1980).

107

111-3-3.

Heat Treatment Behaviour of Oxygen in Silicon as
Measured by Charged Particle Activation Analysis

Y. Itoh and T. Nozaki

Since control of oxygen and carbon in silicon wafers has been suggested to be one of the keys
to the successful future of VLSI (very large scale integrated curcuit) processing,l) there has been an
explosion of articles published in this field.

Gaps remain in our fundamental knowledge of theproperties of oxygen in silicon, such as its solubility and diffusion coefficient. However, the depth
profiling of oxygen in silicon at trace levels has been a very difficult analytical problem. We
developed a simple and reliable method of oxygen depth profiling using charged particle activation
analysis with the 160CHe, p) 18 p reaction. 2), 3) This new method has been applied to theobservation of oxygen distribution after heat treatment of silicon under various conditions. Using
these results we estimated the diffusion coefficient and determined the solubility of oxygen insilicon.
Samples used are CZ silicon < III > B-doped p-type and P-doped n-type with resistivities of
2 - 5 n cm and oxygen concentrations of 6 - 15 X 10 17 cm - 3 and PZ silicon < III > B-doped
p-type with resistivities of 7000 n cm and oxygen concentrations of 5 X 10 15 cm - 3. The samples
were kept at given temperatures between 900 and l250°C in an atmosphere of Ar, N2 or 02 for
1250-1200 .-1150 1050
Takano 8: Maki

Corbett et 01.

Si CZ

800°C]
15hrs

0

I

T

900

°c

Si CZ
B

cl

I 250
100hrsj
in Ar

10

~

E

a..
a..

~c

5+--

o

o

;:

U

2.7 eV

•

10- 11

o

100
Depth

Pig. 1.

200(pm)

Oxygen depth profiles in CZ-

silicon heat treated in argon. (Initialoxygen concentration: A, 9.5 X 10 17
cm- 3 ; B, 6 X 10 17 cm- 3 ; C,8.5 X 10 17
cm- 3 ).

6.5

7.0
7.5
8.0
10000/ T (oK-I)

Fig. 2. Diffusion constant as a functionof reciprocal temperature in comparison
with measurements of other authors.

108

16 to 144 h. Oxygen depth profiles were obtained by the method reported in our previous
paper. 2 ) The resultant oxygen out-diffusion is shown in Fig. 1 for CZ silicon of various initialoxygen concentrations after heat treatment at 1250°C for 100 h in Ar. Similar profiles were
measured for heat treatment at 900, 1050, 1150, 1200, and 1250°C in Ar. The diffusion
coefficients of oxygen were estimated from these experimental results for the given temperatures;
they are shown in Fig. 2, together with those reported by other workers. The activation energy
calculated on the basis of our curve in Fig. 2 is 2.7 eV. The diffusion coefficient is thus givenby
D = 0.58 exp (-2.7/kT).
These results have frequently been extrapolated to temperatures as low as 450°C, where any small
error in their determination at the high temperatures would be magnified. Further results at low
temperatures are needed in order to obtain more reliable formula for the diffusion coefficient.
In Fig. 3 we show the oxygen depth profiles of the samples with different initial oxygen
concentrations after heat treatment in oxygen atmosphere at 1100°C for 144 h. In sample A andB, the oxygen profiles were variable depending on the initial oxygen concentration. The profile
in sample F is for a low initial oxygen concentration, demonstrating the uptake of oxygen fromthe atmosphere. When these three curves are extraporated to the surface of the sample, theygive the same oxygen concentration. This concentration should be the solubility of oxygen insolid silicon at this temperature. It is (3.6 ± 0.5) X 10 17 cm- 3 . Similar profiles were measured
for heat treatments at several other temperatures in oxygen atmosphere.

Figure 4 shows the

1100°C144hrsin 02
A

7 10 18

'"I

E
u

E

c

o
~
c
Cl)

u

c

10 18

u

B

c
Q

/

{--

,

o

o

~
c

~.

Cl)

u

c

0

0

~F

o

~ Melting point

2

100

10 17

200
Depth

Cum )

Fig. 3. Oxygen depth profiles of threesamples with different initial oxygen
concentrations. (A,9.5 X 10 17 cm- 3 ;B, 6 X 10 17 cm - 3 ; F, 0.5 X 10 17 cm - 3 ).

300

7
1/ T (X lO - 4 )Fig. 4.
Solubility of oxygen in solid
silicon. (e: FZ, 6: CZ; 6 X 10 17 cm- 3 ;0: CZ;:< 10 18 cm -3, x : by Kushner).

109

oxygen solubility as a function of the reciprocal temperature.

The results obtained by the present

experiments are slightly different from the results of Kaiser obtained by IR spectrophotometry
and those of Kushner by charged particle activation analysis with the 180(p, n)18F reaction.
Further experiments will be needed to confirm our results.

References
1)l.R. Patel: Proc. 3rd Intern. Symp. on Si Mater. Sci. and Tech., p. 521 (1977);

Proc. 4th Intern. Symp. on Si Mater. Sci. and Tech., p. 189 (1981).
2)

T. Nozaki and Y. Itoh: IPCR Cyclotron Progr. Rep., 1..1., 94 (1980).

3)

Y. Itoh and T. Nozaki: l. Radioanal. Chern., 1.Q, 329 (1982).

110

III -3-4.

Effect of Carbon Precipitation on Gold Diffusion
in Silicon

Y. Itoh and T. Nozaki

It is well recognized that carbon in Czochralski-grown silicon crystals, when its concentration
exceeds a certain critical value, precipitates in a high-temperature heat treatment. The precipitationof carbon exhibits harmful effects on silicon devices, such as lowering of breakdown voltage of p-njunction. 1) The precipitation is also suspected to have certain influence on gold diffusion insilicon. Since carbon in silicon is electrically inactive, it has been investigated mainly by infraredabsorption due to substitutional carbon. To get the total amount of carbon content, we usedcharged particle activation analysis with the 12CeHe, ~)11C reaction.

By combination of thismethod and usual infrared OR) spectrophotometry, the precipitation of carbon was investigated.
Samples used were dislocation free CZ-grown silicon < 111 >, B-doped p-type with resistivities
of from several n· cm to tens of n . cm. Dislocation-free float-zone silicon with resistivity ofseveral kn· cm was also used for comparison. These samples with different initial oxygen andcarbon contents were kept at 1250°C for 100 h in argon. Since little change in the carbon
content after the heat treatment was found by charged particle activation analysis, decrease in thesubstitutional carbon peak in 607 cm -1 is regarded as a result of precipitation of carbon. As foroxygen in silicon, both activation analysis and IR spectrophotometry showed certain decreases of
its concentration in heat treatments. Gold was diffused into the samples with or without heat
treatment at 1000°C in vacuum of I X 10- 8 Torr for 2.5 h.

The results are shown in Fig. I,

where [0] D is the decrease in oxygen concentration caused by the heat treatment. [C] p is thequantity of the precipitated carbon estimated from the reduction of substitutional carbon measured
10.-------------------------~[C]p [010[C ]p+[OJo

Effect of decreases ofFig. 1.
IR-sensitive carbon and oxygen

o

2

4
6
8
10
[C lp ,[0]0 (cm-3 )

12
Xl017

concentrations on gold diffusion
in silicon.

111

by IR spectrophotometry, and [Au]H and [Au]a are the central gold concentrations of the samples
with and without heat treatment, respectively.

The ratios of [Au]H to [Au]a are plotted against[C] p and [0] D in Fig. 1, by !:::. and 0, respectively.

The plots. are for [0] D in samples with

low-carbon contents. A linear relationship exists between [C]p + [OlD and [Au]H/[Au]a asshown in Fig. I (plotted by D), indicating that both precipitation of carbon and escape of oxygen
have similar acceleration effect on the gold diffusion.

Details of this study will be presented

elsewhere in the near future.

ReferenceI)

N. Akiyama, Y. Yatsurugi, Y. Endo, Z. Imayoshi, and T. Nozaki: Appl. Phys. Lett., 22, 630(1973).

112

III -3-5.

Separation and Purification of Carrier- Free 119 Sb from 119mTe
Produced by the Sn(a, xn} Reaction

S. Ambe, F . Ambe, and T. Okada

We have been studying the electronic states of 119Sn arising from cyclotron-produced 38.0 h
11 9Sb in bulk solids by Mossbauer emission spectroscopy.1) - 4)

Recently , a new series ofinvestigations have also been started on chemical states of carrier-free 119Sb hydrolytically adsorbed
on a variety of surfaces. 5)-7) In such experiments, not only non-radioactive antimony but alsohydrolyzable metal ions which compete with 119Sb in adsorption must be kept minimum in thestarting 119Sb solution employed.

As reported previously,5) 119Sb free from non-radioactive

antimony contained in the target can be obtained by milking from 4.68 d 119mTe produced by the
Sn(O' , xn) reaction .

Needless to mention, the most probable undesirable impurity in the 119Sb

solution obtained is tin which originates in the target.
solution by anion exchange of 119Sb (V).8)

Formerly, we eliminated tin from theBut, partial loss of 119Sb due to reduction of 119Sb (V)to 119Sb (III) in the resin phase was inevitable in this method.
In the course of adsorption studies of this year , we found that carrier-free 119Sb (V) is hardly
adsorbed by active charcoal in the pH range 4 - 1O.

Since most hydrolyzable metal ions including

Sn (IV) are effectively adsorbed by active charcoal in this pH range, the above finding could bereadily utilized in the purification procedure of 119Sb in place of the anion exchange of 119Sb (V).
To 20 ml of 0.25 M LiOH containing carrier-free 119Sb (V) or 113Sn (IV) with a small amountof tin carrier, 100 mg of active charcoal was added.
temperature.

The suspension was shaken for 1 h at room

The active charcoal was separated by filtration or centrifugation and the percentageof 119Sb or I \3S n adsorbed on the charcoal was determined by radioactivity measurement.

Asshown in Fig. 1, essentially all the l\3Sn was adsorbed by the active charcoal from the solutionsof pH 4 - 8 , while practically no adsorption of 119Sb was observed at pH 4 -10.

When theconcentration of Sn was larger than 0.8 mM, a part of 119Sb was lost from the solution probably
due to co-adsorption with Sn (IV).

However, the use of active charcoal can be regarded as quite

profitable for elimination of trace of tin from a solution of 119Sb in its final stage of purification.

100-•••• •.Q2 50~oFig. 1.

Percentage of 119Sb(V) (0,

(f)

-0

carrier-free) and 113 Sn(IV) (e, carrier:
6 X 10- 5 mM) adsorbed onto 100 mg

<t

O ~

2

00

00

0

o

o

of active charcoal from 20 ml of 0.25 M

I

I

I

I

4

6

&

10

pH

LiOH after 1 h of shaking at room
temperature.

113

Our present procedure for the separation and purification of 119Sb from the tin target
containing 119mTe is as follows:
A tin plate (1 X 36 X 50 mm, about 13 g, content of antimony 2 ppm) is irradiated with
40 MeV ~.-particles from the cyclotron in a specially designed target box. The target is dissolved
in aqua regia. After evaporation to almost dryness, 119mTe produced by the Sn (~, xn) reaction isprecipitated as metal from 3 M He 1 with an appropriate amount of Te carrier by reduction withsodium sulfite and hydrazine dihydrochloride. After repetition of dissolution and precipitation,
the 119mTe metal is left standing for a few days to allow accumulation of 119Sb by the Ee decayof 119mTe. The metal is then dissolved in aqua regia and dried up. The residue is dissolved in
3 M He 1 and 119mTe is again reduced to metal, 119Sb being left in the solution. After filtration,a small amount of Te carrier is added to the solution and Te metal is precipitated to ensure
removal of 119m Te. The filtrate (3M in He 1) containing 119 Sb (III) is passed through a columnof anion exchanger, Dowex l-X8. After thorough washing with 3 M and 0.5 M HCI, 119Sb iseluted with 0.5 M LiOR and oxidized to 119Sb (V) by air bubbling.

Active charcoal is added tothe solution after neutralization with 0.5 M Hel to pH 6. The suspension is shaken for 1 h atroom temperature and filtered. The carrier-free 119Sb solution thus obtained is used for various
tracer and Mossbauer studies. Antimony in the solution was determined to be I - 4 ppb byneutron activation analysis. The separation of 119Sb from the 119mTe metal could be repeatedevery two or three days.
Further experiments are now under way in order to establish the conditions for eliminating
Sn (IV) with a column of active charcoal.

References
1)

F. Ambe and S. Ambe: J. Chern. Phys., 73, 2029 (1980).

2)

F. Ambe and S. Ambe: IPCR Cyclotron Progr. Rep., 11, 96 (1980).

3)
4)

S. Ambe and F. Ambe: ibid., p. 98.
F. Ambe and S. Ambe: J. Chern. Phys., 75, 2463 (1981).

5)

T. Okada , H. Sekizawa, F. Ambe, and S. Ambe: IPCR Cyclotron Progr. Rep., 14, 86 (1980).

6)
7)

T. Okada, H. Sekizawa, F. Ambe, and S. Ambe: p. 91 in this report.
S. Ambe, F. Ambe, and T. Okada: p. 114 in this report.

8)

F. Ambe, S. Ambe, and H. Shoji: Radiochem. Radioanal. Lett., ~, 349 (1973).

114

Adsorption Kinetics of Carrier- Free 119Sb(V)III -3-6.

S. Ambe, F. Ambe, and T. Okada

Recently , we have clarified chemical states of 119Sb(V) adsorbed on ~- Fe 2 03 surfaces by
Mbssbauer emission spectroscopy . 1),2)

Here, the adsorption kinetics of carrier-free 119Sb(V) ionsfrom an aqueous solution onto ~-Fe2 03 is reported.
Kinetic study on hydrolytic adsorption of metal ions from aqueous solutions has been
payed little attention because of rapid precipitation of hydrolyzed metal ions after neutralizationof the solutions.

Antimony(V) ion is one of the most hydrolyzable metal ions and gives varioushydrolyzed species dependending on the pH of the solution and the concentration of the ion. 3 ), 4)
In this work, the troublesome hydrolytic precipitation of antimony(V) ions was avoided by using a
Its adsorption onto ~- Fe 2 03 surfaces has been shown tocarrier-free radioisotope of antimony.

obey an unexpectedly simple kinetic law.
As the tracer, 119Sb was separated from 119mTe produced by ~-particle irradiation of tin by
the cyclotron. 5 )Suspension of ~-Fe2 03 in 0.25 M LiCI solution containing carrier-free 119Sb(V)ions was shaken at constant temperatures.

An aliquot of the suspension was taken in everyone~- Fe 2 03 in the aliquot was separated

minute for determination of the fraction of 119Sb adsorbed.
by filtration with glass fiber paper.

The radioactivities of 119Sb in each filtrate were counted withan NaI scintillation counter.
Percentage of adsorbed 119Sb after I and 3 h is plotted against pH value in Fig. 1.

Maximum

adsorption was observed at pH around 4, showing almost 100 % adsorption after 1 h shaking.
Adsorption process of 119Sb(V) from the solutions of pH 4.1 at 30 , 40,50, and 60 °C is

100 -oo ~ ~

••

0

100

0
0

•0
•

•
~

c:
S?

Q

•

50 -

0

(/)

•

~

0

c:
S?

•

-+-'

0.

(/)

<r::

0

0

• •0

0

-0

•

50 r-

•0

• •
• •
0

0

•

0

• •

0

•
• •

0

0

0

0

0

0

0

0

0

-0

<r::

. 0

•
0
0

I

I

5

10

0

pH

Fig. 1.

pH dependence of adsorption

0

I

I

I

I

I

2

4

6

8

10

Time ( min )Fig. 2

Increase in percentage of adsorbedof 119Sb(V) on ~-Fe2 03 at 50 °C: • 1 h

119Sb(V) on ~-Fe2 03 with time.

shaking

Adsorption temperature: • 60 °C, D 50
°c, • 40°C , 0 30 °C.

03 h shaking.

115

shown in Fig. 2. Temperature dependence of the adsorption indicates that the adsorption of
119Sb(V) on a-Fe 2 0 3 is a chemisorption. The adsorption was found to follow the rate equation:dx- - = k(a - x)2
dt
where "a" represents the initial radioactivity of 119Sb and "k" is the rate constant of adsorption.
As shown in Fig. 3, the relation between 1I(a - x) versus t exhibits a good linearity, giving therate constant k from the slope. The plot of I n(k X 10 6 ) versus 1IT is shown in Fig. 4. Fromthe slope, the activation energy of adsorption was calculated to be 37 kllmol using Arrhenius
equation.

x 10 - 5r - -_ _ _ _ _ _ _ _ _ _ _ _----.
5

2.0 . - - - - - - - - - - - - - - - - ,4~ 3

o.........

,

~

x 1.0

::: 2

o

-.!C

o

Fig. 3.

2

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

4
Time

Relation of l/(a-x) versus

time. Adsorption temperature:(a) 60°C, (b) 50 °c, (c) 40°C , (d) 30 °C.

3.0

3.1

3.2

3.3 x 10 - 3

1
T

Fig. 4.
Arrhenius plot of theadsorption.

The chemical form of dilute Sb(V) ion in a weakly acidic aqueous solution is reported to be
Sb(OH)6" ,4) while the surfaces of a-Fe 2 0 3 suspended in the solution are known to be positively
charged due to adsorption of protons. 6 ) The adsorption is considered, therefore, to be initiatedby the electrostatic attraction between the negatively charged complex ions in the solution andthe positively charged oxide surfaces and then leads to the formation of Sb -0.;. Fe bonds on thesurfaces as shown by Mossbauer spectroscopy. 1), 2)

References
1)
2)
3)
4)

T. Okada, H. Sekizawa, F. Ambe, and S. Ambe: IPCR Cyclotron Progr. Rep., 14,86 (1980).
T. Okada, H. Sekizawa, F. Ambe, and S. Ambe: p.91 in this report.
S.H. Gate and E. Richardson: 1. Inorg. Nuc!. Chern., 23, 257 (1961).
G.lander and H.l. Ostmann: Z. Anorg. AUg. Chemie, 315, 241 (1962).

5)

S. Ambe, F. Ambe, and T. Okada: p. 112 in this report.

6)

G.A. Parks and P.L. de Bruyn: 1. Phys. Chern., 66, 967 (1962).

116

III -4.

Radiation Chemistry and Radiation Biology

1.

Inactivation of B. Subtilis Spores by Heavy Ions

T. Takahashi and F. Yatagai

Inactivation of~. subtilis spores has been studied using accelerated He, C, and 0 ions, andseveral attempts were made for the interpretation of the results.

To get better understanding ofinactivation , we are doing experiments using Ne ions which became available recently. The
inactivation cross sections preliminarily obtained for Ne ions are shown in Fig. 1, with our crosssections for He, C, N, and 0 ions.1), 2) In Fig. I are also shown cross sections for Pb and U ions
recently published by Schafer et al. 3 ) Analyses are in progress based on Chatterjee and Schaefer's
track structure model 4 ) as well as Katz's theory.S), 6)

1.2..........
N

E

1.0

::t

c
Q

UQ)
(j)
(j)
(j)

0

b

0.6

c
Q

m

.

He

x

C

6.

N

Q

C

0

Ne
Pb
U

2:

&

<U

0

u 0.4
.E

0.2

4

6

Energy ( MeV/ amu )Fig. 1.
Relation between the energy ofions and the inactivation cross sections.
Lines are to guide the eye.

References
1)
2)
3)

F. Yatagai, T. Takahashi, and A. Matsuyama: J. Radiat. Res., 11,90 (1974).
F. Yatagai, T. Takahashi, and A. Matsuyama: ibid. , .!i.: 99 (1975).
M. Schafer, R. Facius, K. Baltschukat, and H. Bucker: Proc. 7th Symp. on Microdosimetry

4)
5)
6)

(1980).
A. Chatterjee and H.J. Schaefer: Radiat. Environm. Biophys., 11, 215 (1976).
R. Katz, B. Ackerson, M. Homayoonfer, and S.C. Sharma: Radiat. Res. , 47, 402 (1971).
T. Takahashi, F. Yatagai, and A. Matsuyama: Sci. Papers I.P.C.R., 74, 51 (1980).

117

III-4-2.

Relative Biological Effectiveness of Nitrogen Ions on
Inactivation of Cultured Mammalian Cells

1. Kaneko, T. Nishimura, T. Ohno, K. Eguchi,

K. Nakano, and T. Inada

Heavy-ions have been shown to have higher biological effectiveness, and are expected to besuperior to X- or 'Y-rays for cancer therapy.
The present study, performed with nitrogen ions, concerns (1) the relative biologicaleffectiveness (RBE) on the inactivation of mammalian cells and (2) the expression and repair of theheavy ion-caused damage in the mammalian cells in culture.
Normal human fibroblasts, IMR 90 cells were maintained and treated as described previously. 1)
Human melanoma HMV cells were cultured in F-12 medium supplemented with 5 % calf serum and0.05 % heat infusion broth (Difco).2) Human epitheloid carcinoma HeLa S3, mouse Balb/c 3T3 ,and Chinese hamster V79 cells were cultured in MEM medium containing 10 % fetal bovine serum.
Colony-forming IMR 90 3T3 cells were cultured with feeder cells previously irradiated with 5500
rad of 60Co 'Y-rays. The expression and repair of the damage after nitrogen-ion irradiation were
performed by incubating these cells at their saturation density.
Five hours before nitrogen-ion irradiation, the cells were seeded onto 25 mm cover glass set
in 35 mm glass petri-dishes.

The dishes were incubated in a humidified CO 2 -incubator until thetime of irradiation. Cell-handling procedures for the irradiation and cultivation were similar to
those described previously}) except for the size of the dishes and without replating after irradiation
because the irradiation dishes with cells were directly incubated for the colony formation. A new
dish holder for 35 mm petri dish was used for irradiation.
Table 1 shows the radiosensitivities for three human cell lines.
The relationship between RBE and LET for inactivation of human IMR 90, HeLa S3, andHMV cells by nitrogen-ion irradiation was found to be similar to that of human fibroblast HF 19
Table 1.

Radiation quality and radiosensitivity of three human cell lines.

Cell line

Parameters'Y-rays

Nitrogen ions
(E=4.7 MeV /amfJ)

RBE

Normal human fibroblast,

Do (rad)a)

153

98

1.5

IMR 90nb)

Human epitheloid carcinoma,

Do (rad)HeLa S3n

Human melanoma,

Do (rad)

HMV

n

1.6
180
2.0
130
9.1

a) The dose required to reduce the number of clonogenic cells to 37 % of their fo rm er value.
b) A measure of the width of the initial shoulder in the survival curves.

1.1
140

1.3

1.0
95
0.4

1.4

118

and Chinese hamster V79 cells. 3 )The patterns 4 ) of the recovery from the potentially lethal damage in IMR 90 and Chinese
hamster V79 cells after nitrogen-ion irradiation were found to be different from the well-known
pattern for the recovery from the potentially lethal damage after ,),-ray irradiation. Studies on thepotentially lethal damage repair of HeLa S3, HMV, and Balbi c 3T3 cells after nitrogen-ion
irradiation are under way.

References
1)
2)
3)
4)

1. Kaneko, T. Ohno, K. Nakano, and F. Yatagai: IPCR Cyclotron Progr. Rep., !.±' 102( 1980).
T. Inada, K. Kawachi, T. Kanai, and I. Nojiri: J. Radiat. Res., 22, 143 (1981).
R. Cox and W. K. Masson: Int. J. Radiat. Bioi., 36, 149 (1979).
I. Kaneko, T. Ohno, I. Suzuki, T. Taira, K. Nakano, and F. Y. Yatagai: J. Radiat. Res., 22,
26 (1981).

119

III -5.

Instrumentation

1.

Gamma-Ray Circular Polarimeter

K. Ieki and M. Ishihara

NUCLEAR INSTRUMENT

Forward scattering type Compton

1polarimeter; conical shape magnet , variable detection angle of emitted[

particle, calculated analyzing power and transmission

In an attempt to study heavy ion reaction mechanism , several m ethods have been employed
to determine spin polarizations of residual nuclei. These methods utilize ~-decay asymmetry of
12B,1) double scattering of protons 2 ) and circular polarization of ,),-rays.3)
Much knowledge wasgiven to light fragment polarization by the first two methods , whereas information on heavy
fragment polarization can be taken only via the third method.
In order to pursue the study of heavy fragment polarization , we are now constructing forward
scattering type Compton circular polarimeter.

The main features of the setup are similar to thoseof Trautmann et al.,3) but following modifications have been incorporated:1)

Trautmann et al. detected emitted particles with ionization chamber and Si detector at

fixed angle.

To study reaction mechanism, however , detection at variable angles is favorable.

In

our setup counter telescopes can be set symmetrically with beam axis in vacuum chamber at varied
angles.

Setting angle can be changed in 5° step.

To gain detection efficiency , the telescope withsolid angle of 20 - 40 msr can be installed and serveral sets of the telescopes can be set at thesame time.

~ Pb

~ Fe

L:. . <·.·:·.:.:.:.:.I AI

ta rget+NaI6"X6"!

oFig. 1.

!

!

!

,

J

50

!

[

,

[

I

100mm

Cross sectional view of the polarimeter.

120

2)

The room required for installation of particle detectors causes the size of chamber tobecome rather large.

Hence , we chose a relatively large volume NaI detector (6" rjJ X 6") to obtainsufficien t efficiency.
Trautmann et al. chose a rather complicated shape of the magnet surface.

3)

adopts a simple conical shape to facilitate easy construction (Fig. I).
incoming ')'-rays ranges 20° - 45 ° which is the same as for Ref 3.

Our setup

The acceptance angle for

To calculate figure of merit of

the setup , we made Monte Carlo simulation code " POL" which includes multi-scattering effect.
Though the analyzing power of our setup is smaller thanCalculated results are shown in Fig. 2.

that of Ref 3 , transmission is larger, and the figure of merit is comparable.
Calc ula t ed value of ana lyz ing pow er and tr ansmi ssio n
X I0 - 2 ~---------------------------------.

5141"::t::

- 0.5

3.-

I

21-

•

•

•

•

•

110 ~--------------------------------~ O
X 10- 4

X 10- 3

h

•

5r-

•

•

- 5

•

•
Calculated value ofFig. 2.
analyzing power (a) and transmission

0

I

I

1

2

Er

0

( MeV)(b).

Right-hand scale oftransmission is relative to 4-7T.

References
1)

K. Sugimoto , N. Takahashi, A. Mizobuchi , Y. Nojiri, T. Minamisono, M. Ishihara, K. Tanaka,and H. Kamitsubo: Phys. Rev. Lett., 39, 323 (1977).

2)

T. Sugitate , T. Nomura, M. Ishihara, Y. Gono, H. Utsunomiya, K. Ieki , and S. Kohmoto:

IPCR Cyclotron Progr. Rep. , 14,28 , 64 (1980).
3)

W. Trautmann, C. Lauterbach , 1. de Boer, W. Dunnweber, G. Graw, W. Hamann , W. Hering,and H. Punchta: Nucl. Instr. and Methods, 184, 449 (1981) .

121

III -5-2.

Neutron Detection in In-Beam Spectroscopy

A. Hashizume, H. Kumagai, Y. Tendow , and
T. Katou

To study the states in neutron deficient nuclei excited by (HI , xn'Y) reactions by in-beam 'Y-ray
spectroscopy , it is important to distinguish other types of reactions such as charged particle
emitting reactions. The n-')' coincidence technique is a useful means to define the neutron emitting
reaction channel.
A liquid plastic scintillation neutron detector has been successfully used for this purpose.
The detector consists of a RCA 8854 photomultiplier optically coupled to liquid plastic scintillatorof 5" diam.X3" NE213.

To distinguish the neutrons from 'Y-rays a pulse shape discrimination

technique has been used. The block diagram used for the n-')' coincidence is shown in Fig. 1.
The selection of pulses caused by neutrons from those by 'Y-rays is made by the difference ofzero -crossing time of pulses. A typical time spectrum from the pulse shape discriminator system
Computer

OK!

4500

C.F.D. : Constant fraction discriminator
P.S.D. : Pul se shape discr iminato r
T.F.A. : Ti ming fi lt er amplifi er

Fig. 1. The block diagram of the electronic system to obtain n-')'coincidence spectrum.
is shown in Fig. 2. Californium 252 was used for the 'Y-ray and neutron source. The time
resolution was considerably improved when the liquid scintillator and the photomultiplier werecooled to 0° C.
Figure 3 shows 'Y-ray energy spectra in coincidence with neutrons obtained when 147 Sm wasbombarded by 100 MeV 160.

For comparison a 'Y-ray singles spectrum is also shown.

If onetakes the ratios of peak areas between 'Y-ray singles and n-')' coincidence for the 2+ 0+ transition in
6 0, 3n) and the 17/2+ 13/2+ transition in 6 0, 4n) reactions, the peak of the 17/2+ 13/2+
transition is 1.3 times larger than that of 2+ 0+ transition in the n-')' coincidence spectrum. Thiseefact reflects the emission of one more neutron in cI 6 0, 4n) than in cI 6 0, 3n) reaction. Thus, toobserve the change of intensity of peaks in singles and n-'Y spectrum is a good means to distinguisha (HI , xn) reaction from (HI, (x-l )n) or other charged particle emitting reactions.

122

105
18 ns

'~4ns

10 4
-

FWHM

89ns
FWTM
10 3
~
c:

Y

:::J
0

u

\1

10.5ns
FWHM

n

10 2

Fig. 2.

A time spectrum frompulse shape discriminator system
100 ~~~--~----~--~----~~~uallL~UU~

o

20

40

60

using ')'-rays and neutrons emitted
from 252Cf.

80 ns

Time

147

0

+

N

Sm + 16 0 ( 100MeV )o ( 16 0, 3n) 160 Yb~ ( 16 0 , 4n) 1 59 Yb(Y)~-----+
N

~

(Y)

.q

<U

u

N

(f)

0

G.J

:::

+

N

~

N

I"-

------

I"------

co

<U

(J)

~

N
~

+
.q

t

N
Lf)

(J)
(Y)

0
G.J

.......
-----N

+

I"-

i

co
0

N
Lf)

-----N

I
(J)

<U

.q

u

LO

..c:

N

.......
-----N
+

0

+

+
N

'-0

LO

.q
.q

c:
c:

+
.q

LO
-----N ~

-

'-0

i~

i N------+i+

coco .......
0

N

.q'-O
(Y) (Y)'-0 '-0

~

0..
(f)

C

:::J

0

U

y-n coincidenceoFig. 3.

1 000
Channel number

2000

A spectrum of ,),-ray singles and of ,),-rays in coincidence withneutrons observed in the 147Sm + 16 0 (lOa MeV) reaction.

123

III -5-3.

Data Processing System at RllAC

H. Kumagai and M. Sasagase

Construction of the on-line data taking and data processing system 1) at RILAC is in progress.
An 8-parameter multi-channel scaler (MCS) interface, a LIST mode interface and a control
panel interface were installed, and another PERKIN ELMER model 3220 super mini-computer has
also been introduced in 1981 , for off-line data processing. The present configuration of the on-line
and off-line data processing systems is shown in Fig. 1. Both users of the on-line computer andthe off-line one can make use of the common line printer, digital plotter and magnetic tapecontroller by switching the input/output switches.

~

On-line data processing
system_ __ __ _ _ __ __ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ __ __ _ _ __ __ _~A~

Off - li ne data processing sys t em
~

CPU

CPU

P- E 3220

P- E 3220

MOS MEM ORY

MOS MEMORY

768 KB

512 KB

Fig. 1.

The data processing system.

The specifications of the custom made interfaces are described below.
For the MCS interface:I) Eight independent scalers (24 bit, 100 MHz) are included so that 8 input pulses can becounted simultaneously.

124

2)

Data address on the main memory is appointed with a universal logic interface (ULI).

3)

Readout and modification of the contents of the main memory are performed with DMA

channel.
4)

It is possible for a user-written program to control the interface ignoring the condition ofseveral switches on the front panel.
For the LIST mode interface:
1)

Maximum 15 NIM-ADC's can be connected and coincidence data are sent to the main

memory event by event.
2)

There are two coincidence modes, the internal coincidence mode and the externalcoincidence mode.

For the internal coincidence mode, coincident data are taken into the interface

when some ADC signals are input within a coincidence time, which is previously defined by a user.
For the external coincidence mode, gate signals for each ADC are generated by supplying an externalcoincidence signal to the interface.

Coincident data are simultaneously taken into the interface for

maximum 16 combinations of the ADC's in this mode.
3)

Coincidence data are sent to the main memory from the interface through DMA channel.

4)

There are two buffer areas of 16 k byte on the main memory.

The data on the buffer

area are recorded on a magnetic tape or a disk when one of these buffer areas is filled up withdata.
For the control panel interface:
1) This interface is designed to enable a user to control the PHA, MCS, and LIST interfaces
and to do I/O operation to a disk, the magnetic tape, the line printer or the plotter by pressing thebutten switches on the panel.
Development of softwares to control the above-mentioned interfaces is in progress. Because
many functions are required to the system, these functions are shared with many separated tasks
and care is taken so that close communication is possible among these tasks. The on-line dataprocessing system is planned to be accomplished by the end of February in 1982.

Reference
1)

H. Kumagai and T. Wada: IPCR Cyclotron Progr. Rep., .!.i: 156 (1980).

125

N.

ACCELERATOR DEVELOPMENT

1.

New Gas-Feed System and Acceleration

Test of

Heavy Ions with Gas Mixing

K. Ikegami , K. Ogiwara, and I. Kohno

A gas-feed system was improved for stable operation of the ion source.

A method of mixinglgas ) through the gas-feed system was applied in the production and acceleration of heavy ions suchas C4 +, 0 5 + , N 4 + , N 5 + or Ne 6 + ions, to increase beam intensity and stability of source operation.
Figure I shows a block diagram of the new gas-feed system. This system consists of four
reservoirs, additional valves and two gas-feed lines having a gas flow controller. The reservoirs andadditional valves are placed in the control room. Two gas controllers are installed in theunderground room of the cyclotron vault, because the ion source must respond quickly to thechange of gas flow without picking up RF noise. Figure 2 shows a block diagram of a gas flow
controller system. This system is composed of a piezoelectric valve 2 ) PV-10 made by VEECO, a
gas flow controller made by RIKEN and a mass flow meter by HASTING.

The valve PV -lOis

operated by an electric pulse with a repetition rate of 300 Hz and an amplitude of 80 - 100 V
supplied by a controller.

By varying the pulse duration from 0 to 6 % one gas flow controller

can be remotely controlled over a range of 0 to 10 cc/min and the other from 0 to 5 cc/min.
In the case of mixed gas, the main gas was supplied to the ion source through one gas-feedline and the support gas was supplied through the other line. Rare gases, such as He, Ne , Ar, Kr,
and Xe, were mainly used as the support gas. To investigate the gas mixing effect, heavy ion
source of electron-bombarded hot cathode type 3 ) was used. In the test run the electronbombarding power was switched off after the source was ignited to avoid effect the other than the
E.M.V
Yellow
Gas Flow Controller
Ion Source
E.M.v

Blue

Control Room

Gas Flow Controller

Cyclotron RoomFig. 1.
A block diagram of the gas-feed system. Yellow line indicatesa path of the main gas and blue line a path of the supporting gas.

126

-

-

Gas

Ion Sou r ce

Ov5V

iJUL
~ 3msetDut y Gv6 %Cyclo t r on RoomControl Room
Yell ow : O~5 cc /min
Bl ue

Fig. 2.
A block diagram of the gas
flow controller system.

: 0-1 0 cc/min

mixing of gas.

The main gas was decreased gradually and the supporting gas was increased tokeep constant arc power and arc impedance. The beam intensity of heavy ions extracted fromthe cyclotron was measured with a gate drop probe at the entrance of the beam transport system.
Figures 3 and 4 show the beam intensity of 76 MeV C4 + when CO 2 and Ne gases are mixed,
and 103 MeV 0 5 + when 02 and Ar gases are mixed, respectively.

In both cases optimum

mixing rate of gases exists and the gas mixing is effective to increase the beam intensity.

As theresult of the test , it was found that the effect of gas mixing depends on the kind of the supportinggas. In the production of C4 + ions using CO 2 gas, Ne, Ar, and Kr gases were effective as
supporting gases while He was not effective. In the case of 0 5 + using 02 gas Ar gas was effective ,but neither Ne nor Kr was effective.

In the case of N 5 + using N2 gas, Ne and Ar gases wereeffective , but neither He nor Kr was effective.

In the case of Ne 6 + using Ne gas, no effective

supporting gas was found. In all effective case, time duration of stable operation of the source
was increased. We think from the result of the test that gas mixing is effective to stabilize thearc plasma in the ion source rather than for the beam intensity enhancement of heavy ions.

C4+
E = 76 MEV

GAS : CO 2 + NE
PARc=1.76 KW

2.0

--

BEAM

L1.J
~

~ 1.5
L1.J

=

~

. ZARc=lOO n

~

c::r:

:E:

~ 1.0

1.0'0
u

(/)

=
L1.J
~

=

~ 0.5

L1.J
p:)

w

= Fig. 3.

The extracted beam intensity for

76 MeV C4 + at the gate and Ne gas flow to

o

0.5
1.0
1.5
CO 2 GAS FLOW (CC/MIN)

maintain Z arc constant as a function of CO 2
gas flow.

127

05+

0.7

E = 103 MEV

GAS : O2 + AR

0,6o

PARC=2,5 KW~ 0 .5

Z=lOO [I

'-'

l1.J
I--

c::::x::<..!:J

l1.J

=

0.4

I--

PARC=2.49 KW

I--

Z=87 [Ic::::x::

0.3

~ 0.3
(/)

=

~

W
I--

-= 0.2:E
c::::x::

W
!Xl

O.l~
<..!:J

0,1

o

0,5

1,0

1,5

O2 GAS FLOW (CC!MIN)

2.0

Fig. 4.
The extracted beam intensity for
103 MeV 0 5 + at the gate and Ar gas flow tomaintain Zarc constant as a function of 02
gas flow.

References
1)
2)
3)

E.D. Hudson, G.A. Palmer, and C.L. Haley: IEEE Trans. Nucl. Sci., NS-24, 1950 (1977).
Y. Sakurada, G.D. Deharen, W.J. Walterscheid, S.M. Rielamowicz, R.L. Haisler, and H.W.
Peeler: ibid., NS-26, 2175 (1975).
T. Kageyama, K. Ikegami, and 1. Kohno: IPCR Cyclotron Progr. Rep., l.±, 4 (1980).

128

N -2.

Beam Acceleration Test at RllAC

T. Kubo , T. Kambara, Y. Miyazawa, M. Hemmi,
Y. Gono, T. Inoue, T. Tonuma, M. Kase,
M. Yanokura, Y. Chiba, T. Fujisawa,
and M. Odera

In the spring of 1981 , the beam acceleration test by synchronous excitation of six resonators
was started to confirm the basic design of the heavy-jon linac (RILAC).
circuitsl)

Simplified control

were fabricated for radio-frequency (RF) system 2 ) and were used to attain the stableacceleration.

Ions of Ar4+ and N+ have been accelerated successfully at the frequency of 20 MHz.

( I) RF system
The beam acceleration synchronizing more than one resonator is difficult without the control
circuits for the RF system. 3 )As the installation of such control circuits is not completed, we

made simplified ones to stabilize the operation of the RF system.

Each of them includes , asdescribed in detail in Ref. I, an amplitude regulator of accelerating voltages , a semi-automatic tunerof the resonator and a phase shifter.
voltages can be corrected by them.

Changes of the amplitude and phase of the accelerating

Adopted acceleration frequency was 20 MHz , which corresponded to energy gain of 0.8
Me V / nucleon.

Calculated RF voltages of the resonators for the Ar4+ - and N+ -ions are shown in

Table 1, assuming that the phase angle for synchronized acceleration is - 25 deg.
Table 1.

Parameters of the RF system and the injector.
Ar4+

N+

225 kV

315 kV

#1

90

126

#2

100

140

#3

115

161

#4
#5

125

175

140

196

#6

150

210

Ions
Injector
Resonator(2) Beam acceleration
The ions produced in a PIG type ion source 4) were accelerated by an electrostatic injector,S)and analyzed by two dipole magnets ,6) then led into the first resonator.

The accelerating voltagesof the injector are also shown in Table 1.
To confirm acceleration at the linac , it is necessary to measure the energy of the output beam.
Two methods were available.

One was measurement of the energy spectra by a Si detector placed

129

in the beam path. The other was an analysis of the beam by a switching (SW) magnet 7) installed
downstream of the last resonator.
The former method is adequate to measure a small amount of the beam and was used in earlystage of the acceleration test. For protection of the Si detector, the beam was collimated by acopper foil which was 15 11m in thickness and had a pinhole of 10 11m in diameter. The
acceleration was optimized one by one from the first resonator, referring to the energy spectra.
Parameters of the RF system (amplitude and phase) and those of focusing elements (Q-magnets)
were adjusted so that the energy spectra would have a peak corresponding to the designed energy
gain of excited resonators. Figure I shows an example of the optimized energy spectra of the
N+ -ions accelerated when the first three resonators were excited. The peak found at the rightside shows the ions accelerated synchronously , whose energy is 5.8 Me V. The peak at the left
side, which has the energy of ions accelerated only by the injector, is supposed to be of atomic
nitrogens neutralized by charge exchange process in the injection region. The energy spread of theaccelerated ions is less than 1.7 % (FWHM).

Energy spectrum of the N+ -ions accelerated by
Fig. 1.
the first three resonators.
~ater, we confirmed the acceleration by the SW magnet as the beam current increased.

The
optimization procedure was similar to that of the former one except that the field of SW magnet
was set according to the energy gain of excited resonators and the adjustments were made byreferring to the beam current. Figure 2 shows an example of momentum spectrum of theAr4+ -ions accelerated by all six resonators , which was measured by scanning the exciting currentof the analyzer magnet?) after the SW magnet. Energy obtained is 32 MeV and the energy spread
is estimated to be about 1.5 % (FWHM).
The accelerated Ar4+ -ions were transported to A-I and B-1 channels of target area.7) Beamcurrents were more than 10 nA for each channel. Acceleration efficiency was obtained bycomparing the beam current at the entrance of the first resonator with that at the end of thechannel and was, so far , about 1 %.
The accelerated Ar4+ -ions were provided for experiments of atomic physics at the B-1 channel
for the first time in autumn.
The acceleration of other ions (0+ , Xe 8 + , etc.) and the acceleration at other frequencies areplanned now.

130

488\3 . ,--~----.--~--r--~--.--~---''--------~-~

81/11/13>- 3B8t;1.

· AR-40(4+)
32 MEV
20 MHZI/)

Z
W 2888.
tZ~ 1888.
W~

114.99116.06

BR MRG CURRENT (R)
Fig. 2.

1:8 .89

12 9.88

Momentum spectrum of the Ar4+ -ions accelerated by all six

resonators.

The unit of vertical axis is arbitrary.

References
1)

T. Kubo, M. Hemmi, and Y. Chiba: p.137 jn this report.

2)

T. Kubo and Y. Chiba: IPCR Cyclotron Progr. Rep., 14, 123 (1980).

3)

Y. Chiba: ibid., p. 120.

4)

M. Kase and Y. Miyazawa: ibid., p. 132.

5)
6)

M. Hemmi: ibid., 11, 145 (1979).
M. Kase, M. Hemmi, and S. Nakajima: ibid., p. 147.

7)

M. Hemmi, Y. Miyazawa, and M. Odera: ibid., 14, 126 (1980).

131

N -3.

Performance of Light Link System for Control of Instruments
on High Voltage Terminal

M. Hemmi

An optical fiber light link system which is insensitive to various electrical noises has beendevised to control the instruments such as the ion source or vacuum pumps on the high voltage
terminal, potential of which is as high as 500 kV. Since frequent on-off and fine tuning operationof the ion-source parameters from the control room is required , the usual mechanical control using
the insulator rods has been abandoned in favor of an indirect control method which is more
flexible. The method is based on the use of the optical link which transmits information throughoptical fibers by modulating infrared light.
(1) On-off signal channel
Usual method of the pulse code modulation was avoided , because puslive noises are numerous
around the high voltage terminal where Corona or brush discharge is always present. Instead , afrequency modulation scheme has been adopted. The modulating frequency is chosen rather low
and is between 500 and 2500 Hz. Mechanical tuning forks are used as the frequency discriminatorin this audio-frequency range. The forks have an excellent characteristics as filter and are reliable,
low cost and easy to tune. Figure I shows schematically the on-off control system using
sinsoidally modulated light. At present , there are 32 channels for command signals from thecontrol console. The number of the channels can be expanded up to 60 when necessary.
To avoid any error in the important operation, a double signal coincidence scheme is used forsuch command. In that DTMF (dual-tone multi-frequency) scheme only signals with coincident
output from the two filters are accepted and addresses are specified by the two frequencies. Forless important command , single frequency is assigned for each kind of operation. In Fig. 2, a
block diagram of the on-off operation system is indicated. In that figure, in the down link channel
Inp ut

~

T·F
OSC
/'-

h

Ph ot o-rLED ~ -,----------,""",",---

2
I
I
I

I

I
I

I
I
I

I

,-,-===-=--32
32ch Transmitter & rece iver
( Mu lti - frequ ency)

Fig. 1.
Scheme of the optical link system which uses frequency
modulation of light. T.F osc is the oscillators using tuning fork.
Av is an amplifier. LED is a light emitting diode. hv is lightflying in the optical fiber. Ai is also an amplifier. AGC ,automatic gain contr.ol. BPF, band pass filter.

132

m

c::

.~
I-

ControldeskTransmitte r32ch

IIso lati on

500kV Terminal

Fig. 2.

Earth level

Block diagram of the light link system for on-off operation.

which conveys the status information on the terminal, single frequency characterization scheme issolely used.
(2) Analog signal channel
We have not used the sophisticated multiplexer and ADC (analog to digital converter)
combination. We have set up a simple and straight forward system using V/F (voltage to frequency
converter) and F / V (frequency to voltage converter) circuits together with the LED (light emitting
diode) and Photo-transistors. Each channel carries only one kind of analog signals as shown in
Fig. 3. The scheme is very simple and its maintenance and expansion work needs no sophisticatedtechnology. The conversion coefficients in this system are 100 mV/lO kHz for V/F and 10
kHz / 10 V for F / V, accuracy being 10 bits.

+~v~
~. ~

l~Om V V/F
Com

;EF~
I

I
I
I
I
I

~:

:::LJ~~lJ

500kV
Iso lati on(3)

High voltage isolation amplifierFig. 3.
scheme for transmission of analog signals,
using V/F and F/V converters.

Selection of the optical fibers and mating of the connectors

Among the numerous brands of the fibers in the market, those having a large numericalaperture and of low cost were selected.

Mating the connectors to the ends of the fiber cable wasmade by ourselves without difficulty.
As stated above, our optical data link system uses only standard parts found in the market
and maintenance or expansion of the system is easy. Its structure is very simple and a high degreeof reliability has been achieved. The system is found free of misoperation by virtue of thefrequency modulation scheme using the tuning forks, especially, the DTMF method guarantees
transmission of the important command without receiving perturbation from the electrical noises
present in the injector room.

133

N -4.

Metal Ion Source

M. Kase, Y. Miyazawa, and T. Chiba

A metal ion source for the linac has been constructed and tested for AI, Ni, and Cu ions.
The source is of a hot cathode PIG type with a sputtering electrode.!)' 2) Figure 1 shows
schematically a cross sectional view of the metal ion source. The source is designed to be set on
the same position in the magnet as the gas ion source described in Ref. 3 . . Therefore thestructure of the metal ion source is almost identical to that of the gas ion source except for anode.
The anode is composed of three parts: upper, center, and lower parts. The upper and lower
anodes (A and B in Fig. 1) are made of copper and cooled by contacting with the water-cooled
block (C in Fig. 1). The center anode (D in Fig. I) is made of stainless steel and heated by arc
plasmas up to around 300°C without being cooled during the operation in order to prevent
deposition of sputtered material on the inside surface of the anode. A molybdenum plate witha beam slit (1 X 10 mm 2 ) is installed on one side of the center anode. On the opposite side of
the beam slit, the sputtering electrode is inserted through a hole on the anode wall. The sputtering
electrode is a rectangular block, 4 X 9 X 20 mm 3 in size. The electrode is made of the material
to be charged in case of Cu and AI.

For Ni, a 2 mm thick sheet of the material is soldered on acopper backing so as to prevent disturbance in the magnetic field. The sputtering electrode issupported by a water-cooled copper holder. The space between arc plasma and the sputtering
electrode can be adjusted by moving the holder remotely from outside of the vacuum chamber witha set of some gears and rods. A negative voltage (0 '" -1.5 kV) with respect to the anode can beapplied to the sputtering electrode.

Fil ament
Water

Fig. 1.

Cross sectional view of the metal ion source.

The test of the metal ion source was carried out at a test bench of ion source which wasconstructed in 1979. An arrangement of the magnet and beam extraction system in the test
bench is almost the same as that in the injector of the linac. 3 ) Argon was used as supporting gas
in the case of Ni and Cu, while neon was used in the case of Al because a value of mass-to-charge

134

I.

22Ne l +

10- 5

n

J

AI'; r1

~

10- 6

AI2+

I

~ 10 -

I
I
I

I~
11\

t

~ I

A

:::l
U

E

1\
II

Q)

1\

CU

CO

I\
II I
II
.1 1\

10- 8

1\11\,,i ll II

1\

\1 I

\

I

I

'\

1

II

I

I' :
"~I
n II I Aii,

~

I

\

\

I

II

I
I

I

I II

\

h

U

rv
o

tl

"

d~ v

10- 9

AI3+
I

~

I

~:

1\

A

22 Ne3 +

I

I

7

I

n

(

I

I

Ne3+

AI 4+1A~

tl • II

20

I~~ VI) Ic

22 Ne2 +

,

r\

~\
\

,

,

'I

\
\

'\

j/ ~

'IV

Ij(J

I

'-J

1-.

5

15

10

20

Ext rac tion voltage ( kV )Fig. 2.
The extracted beam current versus the extraction voltage when Al
was charged. The magnetic field strength = 5.2 kG, the arc condition =300 V X 0.5 A and the sputtering voltage = -300 V for the solid line ando V for the dashed line. The supporting gas was neon. The beam currents
are measured with a Faraday cup (30 mm¢ aperture) located at the same
position as that of the beam stopper in Fig. 2 of Ref. 3.

Ar 2 +t

Ar 3 +(\l10 - 5 ~-----------'~rr-------r-'-----------~Ar +Ni 1 +

!
K

r\

l

\

I Ni 2+r+"Nrj i'; j

r

Ni 5+

I

I

10 - 6~--_~.-11~'-1~~~+4--;+--~~----~----~

I' !
Ilm/\"\~:
I, I

'I

C

I

Q)

I

~;
Ij

f\

I

1",

II

I I

I IJ
I 11

I I

I I

N ~r) lI i~ :r,~10 - 7~--11-4~~/~~----~~-r~---#~
1 -r--~

IiJ

u
E

r

~

V

I

OJ

\

~" ~

II

I

I

II \

,

\

'

~ ~
\

10 - 8~--4+
I~WI+-----~-----------r------~~~:\-11'---'Ii

I

~
I II

~

: I

~

I~

Fig. 3. The extracted beam current
versus the extraction voltage when Ni
was charged. The magnetic fieldstrength = 5.2 kG, the arc condition= 420 V X 0.9 A and the sputtering

voltage = - 500 V for the solid line
1O - 90L--..J.IIIUI_ lil,1L------'-5----- - - - -- ---,J15 and 0 V for the dashed line.
The
10
[,I

.J.....

Extr act ion voltage (k V)supporting gas was argon.

135

ratio (m/q) for A1 2 + is close to that for Ar 3 + . The m/q spectra, when AI, Ni , and Cu werecharged ) are shown in Figs. 2, 3, and 4, respectively. In each figure, the m/q spectra when no
voltage was applied to the sputtering electrode are shown by dashed lines.
I
~

10- 4

II
I
I

Ar +
1

.
~

Ar 3+

I

II

~

II

'1

I'
,I

'I

I

I

I

Cu 2 +

,

~

I
I

Cu 4+
Cu 3+

!

C~l + I

ft

i

I

+
E

cu

0+
W
Ii
I ~
'1
I ,~

'1I

,

10 - 7

JI

,

'I
II
I

,

I

+
I"S
I

I

Cu 6 +

~

1\

1-1

I

I

t

"1
/11

: 1\

o

+

1°

,I

10- 8

n

C+

I
I

I,

~

II

.~

II
I

I

Q)

co

Ar 4+

t1

' I,
' I,

: :\!\.I'

5

Y':It-i

Ii:
II
I

,

10

\J

~ n

~
15

Extraction voltage ( kV )Fig. 4.

The extracted beam current versus the extraction voltage

when Cu was charged. The magnetic field strength = 4.3 kG,
the arc condition = 400 V X 1.5 A and the sputtering voltage =- 500 V for the solid line and 0 V for the dashed line. The
supporting gas was argon.

References
1)
2)
3)

H. Schulte, W. Jacoby, and B.H. Wolf: IEEE Trans. Nucl. Sci., NS-23 , 1042 (1976).
K. Ikegami, T. Kageyama, and I. Kohno: J pn. J. Appl. Phys., !2., 1745 (1980).
M. Kase and Y. Miyazawa: IPCR Cyclotron Progr. Rep., 14, 132 (1980).

136

N -5.

Construction of ECR Ion Source

M. Yanokura and M. Odera

Development of an electron-cyclotron resonance (ECR) ion source has been started to get
multiply charged ions or high intensity beams of low-charge light ions.
stand of the ECR ion source.

Figure I shows the test

The ion source has only one ECR cavity which is insulated fromthe other components and is kept at a positive high voltage up to 10 kV.

A magnetron is used as

an UHF power source and its output power is 1.6 kW (CW) at 2.45 GHz.

The UHF power is

supplied to the ECR cavity through an isolater, power monitor , EH tuner and RF window. Three
diffusion pumps are installed in the test stand.

One pump evacuates mainly the volume of the

ECR cavity , and the other two pumps evacuate the volume of the beam extraction and analyzing
systems.

These systems, pumps and the UHF power source , are at the ground potential, and are

insulated from the ECR cavity.

The beam extracted from the ion source is focused by an einzel

lense and analyzed by a magnet having a maximum Bp of 94.5 kGauss· cm.

After analyzing, thebeam current is m easured with a Faraday C11p.

7

Fig. 1.

Plan of the ECR ion source test stand.

1: 2.45 GHz

magnetron , 2: isolater , 3: power monitor , 4: EH tuner ,5:

RF window , 6: gas valve , 7: 600 Lis diffusion pump ,8: insulater, 9: main coil , 10: ECRcavity , 11: extractor
and einzel lense , 12:1500 Lis diffusion pump , 13: analyzing

magnet, 14: Faraday cup.
This ECR ion source was tested using Ar gas.
flow rate of I

When Ar gas was fed into the ECR cavity at a

cm 3 /min , the pressure in the cavity was observed to be around10 - 4 Torr.

Plasmais seen to be formed in the cavity at a relatively low power level when the UHF power was
supplied , and a few nA Ar2+ beam was measured at the Faraday cup.

However, the plasma

formed was not such that one would have expected in its distribution in the cavity.

It is supposedthat this result is due to the inadequate position and geometry of the vacuum window in the
wave-guide.

Improvement of the window is supposed to be necessary.

137

N -6.

Simplified Control Circuit for RllAC RF System

T. Kubo, M. Hemmi, and Y. Chiba

The amplitude and phase of the radio-frequency (RF) voltage generated in a resonator oftenchange due to detuning of the resonator or shifting of the gain of amplifier. The control system
for the RF system of RILAC,1) described in a previous report,2) was designed to include anautomatic tuner and an amplitude and phase stabilizer. But it has not yet been installed as somemodifications were found to be necessary. A simplified control circuit was fabricated as atemporary substitution for it and was used for the beam acceleration test. 3)
The RF system consists of six resonators combined with power amplifiers.
control circuit is identical for each combination.

Design of theIts schematic diagram is shown in Fig. 1.

Amplitu deco ntrol signa l~Phase control
signalII_ _ _ _ _ _ _ _ ...JI

Fig. 1.

Schematic diagram of the simplified control circuit.

The common signal for the system, applied as a drive signal of the amplifier and a phasereference , is provided by a frequency synthesizer and is distributed by a resistive power divider to
six transmission lines which have identical electrical lengths. Each line provides the signal which
has the identical amplitude and phase to the respective amplifiers.
The initial part of the control circuit is a phase shifter, which is composed of inductances andvariable capacitive diodes.

The phase of the drive signal can be adjusted by varying the bias

voltage of the diodes and the adjustable range is 40 deg. The RF voltage of each resonator shouldhave the same phase to accelerate ions syn chronously. As this condition is almost satisfied byequalizing the length of the transmission line, the phase shifter is useful only when fine adjustments
are necessary.
The amplitude of the RF voltage of the resonator is controlled by varying the attenuation of
the drive signal with an attenuator included in the amplitude controller. A PIN diode is used as
the attenuator which is continuously controllable by an external signal. To stabilize the amplitude,
it can be driven by a rectified feedback signal from a voltage pick-up of the resonator.

138

Tuning of the resonator is maintained by a semi-automatic tuner. As this tuner cannot tune
the resonator automatically by itself, the tuning should be made manually. It compares the phaseof the RF voltage of the resonator with that of the phase reference by use of a double balanced
mixer (DBM) as a phase detector and detects the detuning of the resonator as a phase change. The
output of the phase detector controlls a servomotor and drives the capacitive trimmer of theresonatorl) to correct the phase change i.e. the detuning. Therefore, the phase of the RF voltage
must be adjusted so that the phase detector will have the output of 0 V when the resonator is
tuned (the DBM has the output of 0 V when the phase difference between input signals is 90 deg.)
This adjustment is made by a variable delay after the amplitude controller. The tuner is not
activated until these adjustments are completed and the normal RF voltage is generated.
The power amplifier can be driven with a pulse signal to tune the resonator. The capacitive
trimmer is manually moved monitoring the pulse shape of the RF voltage of the resonator, until it
becomes the normal shape as is shown in Fig. 2. Figure 3 shows an example of the pulse shapewhen the resonant frequency is slightly different from driving frequency.
Multipactoring phenomena can be easily overcome, if the resonator is tuned, by driving theamplifier with a signal which has enough amplitude and a fast rise time (less than a few
microseconds).
The control circuits are linked to a control computer (HP-I 000)4) and can be operated byremote control.

Fig. 2.
The pulse shape of the RF voltage(upper) when the resonator is tuned and thatof the drive signal (lower). The horizontal
scale is 0.2 ms/div. and the vertical scale isarbitrary.

Fig 3.
The pulse shape of the RF voltage(upper) when the resonator is off theresonance, and that of the drive signal (lower).
See the caption of Fig. 2.

References
1)

T. Kubo and Y. Chiba: IPCR Cyclotron Progr. Rep., 14, 123 (1980).

2)
3)

Y. Chiba: ibid., p. 120.
T. Kubo , T. Kambara, Y. Miyazawa, M. Hemmi, Y. Gono, T. Inoue, T. Tonuma, M. Kase,
M. Yanokura, Y. Chiba, T. Fujisawa, and M. Odera: p. 128 in this report.

4)

T. Kambara: IPCR Cyclotron Progr. Rep., 11, 134 (1979).

139

N -7.

Design of Compact Quadrupole Magnet

Y. Miyazawa and M. Hemmi

A compact quadrupole magnet of a moderate strength is frequently desired so that it can beinserted in the narrow space of the beam line to modify the orbit dynamics. One of the examples
of such requirement is the change of beam characteristics on the targets.

Another is the changeof the beam property by a possible replacement of the ion source by a new type of source.
Figure 1 shows a design which has an integrated strength of 75 kG for pole to pole gap of 25.4 mm
and a pole length of 15 cm. The tape coil technique which has been improved and used
extensively in the linear accelerator project is also used for this magnet.
specification of the magnet designed.

Table 1 is the

456
228
150

228
150

o

L.O
N

~Lr---4---,---L---- - - - - -L..----++---.'--

Fig. 1.

---r- ----'-

Cross section of the doublet quadrupole magnet designed.

Table 1.

Design specification of the quadrupole magnet.

Field gradient

5 kG/cm (maximum)

Pole length

15 cm

Aperture (pole to pole)25.4 mm

Outer diameter

20.4 cm

Maximum ampere-turn

4000 ATPower consumption

0.75 kW (maximum)

Weight

50 kg

140

N -8.

Simple Pepper-Pot

Device for Beam Diagnostics

M. Hemmi, Y. Miyazawa, and T. Inoue

A simple pepper-pot device was fabricated and is being used to get a rough indication of thebeam characteristics injected into the first cavity.

Figure 1 shows its sketch showing the way ofuse in combination with a beam-profile monitor. It is found useful for tuning of beam parameters
to have a simple and intuitive presentation of the beam emittance, not necessarily of very complete
one, at the operation console. In Fig. 2 an example of the beam profile measured by the beamscanner is given. By knowing distances between peaks in that Figure, the degree of convergencecan be estimated comparing with the hole distance in the pepper-pot plate. Two other emittanceprobes were also installed already in the injection beam line. We can get a complete information of
the beam emittance by their use when necessary. However, in most of the beam steering procedure,
the simple and quick presentation of the results of manipulation of the operator is useful and an
exact measurement is scarecely needed.

Together with a program to display on the CRT terminalof the control console the beam trajectory predicted in the later cavities by injection of the beamwith the parameters estimated, the pepper-pot device has made the beam steering procedure mucheasier.

Pepper - pot device

Fig. 1.

Arrangement of thepepper-pot and a beam-profile
monitor combination to measure
beam property.

Fig. 2.

An example of beam profile measured

when the pepper-pot is inserted in the beam.
Beam is Argon ion beam of energy 860 ke V is
used.

141

N-9.

Performance of Digital Emittance Measuring Device

I. Yokoyama, M. Kase, and T. Kambara

A multi-wire beam emittance measuring device was designed and fabricated last year .1) The purpose is toobtain the detailed information of beam emittance quickly by the aid of the control computer HP-IOOO.2) The
device is composed of two beam probes, a driving system with pulse motors to move the probes and a circuit
system with two microprocessors to measure and digitize the beam current.

One of the two probes is for themeasurement of emittance in the horizontal direction (x-direction) and the other is for that in the vertical direction(y-direction).

One of the microprocessors is linked to the control computer via the HP-IB bus.

The computer

processes the data and displays the results.
The structure of the multi-wire sensor in the probe was modified and the performance of the device wastested with an actual beam in the beam injection line of the linac during 1981.
Figure 1 shows the schematic of the emittance measurement probe.

The probe consists of a slit with 0.2 mmof width and 30 mm of length and a multi-wire beam sensor placed behind it at a distance of 75 mm.

The

multi-wire sensor consists of 30 wire strips made of Ni-Cr alloy evaporated on a 2 mm thick ceramic plate andalso plated by thin gold.

Each wire strip is 34 mm long and 80 pm wide and is placed in parallel at intervals of

40 pm.

The sensor became more compact by the use of the evaporated wire strips than by the use of separated

wires.

Figure 2 shows the multi-wire sensor with the wire strips.

¢90~t--it--------'--t---,--if-----H- +-j

C
<lJ

E

<lJ

>

o
L

<

Ion beam

c

.S2
u

2:

o

beam
se nso r

suppressors of
secondary elec tronsV

\
\

sl it

( O.2mm X 30mm )

34

50
75

Fig. 1.

Cross sectional view of the probe.

Fig. 2.

Multi -wire beam sensor. . Detailed drawingof the wire strips is shown in the circle.

142

A program "EMTNl" was developed for the control computer to interface to the device. From the CRT
terminal of the computer, an operator sends a command to trigger the movement of the probe, to do a single orsuccessive measurements and to transfer the data to the computer. Each command consists of two ASCII
characters. Table 1 lists the commands and their functions.
Table 1.

The commands to the microprocessor and their functions.

CommandFunction

ZC

Zero drift check of the amplifiers

GC

Gain check of the amplifiers

XO , YO

Beam emittance measurement in one direction (x or y)

XY

Beam emittance measurement in both directions

IX, IY

Measurement of beam current of each wire at one probe position

DO

Transfer of zero drift check data to the computer

Dl

Transfer of gain check data to the computer

D4

Transfer of measured data at one position by IX or IY command

D6

Transfer of emittance data for x-direction

D7

Transfer of emittance data for y-direction

D8

Transfer of emittance data for both directions

The drift of the zeros and the gains of the amplifiers for the wires can be checked for the correction of themeasured data.

The command ZC triggers the zero check and the command DO triggers the transfer of the data

to the computer. When the gain check is initiated by the command GC, a current of 60 nA is input to each
amplifier from a current source, and the data are transferred to the computer by the command Dl.

(a )Emittance Measurement1-----+-----+X(b)

Emittance Measurement1--------IW1'-----+yFig. 3.
Measured results of beamemittance displayed on graphic CRT
display: ( a) x -direction, (b) y -direction.

143

The command XO triggers the sequence of emittance measurement in the x-direction.
direction is moved horizontally and stepwise with intervals of 2 mm.

The probe for theAt each stop, 30 data are obtained, which

consists of the beam current of the 29 wires and the beam current of the probe itself.

The probe stops at 19

positions for the measurement of the beam current and one position far from the beam for the zero check.
Therefore the total number of the data from one measurement is 600.
memory of the microprocessor.

The data are digitized and stored in the

The command D6 triggers the transfer of the stored data to the computer.

If thecommand D6 is sent before the completion of the measurement, a message is displayed on the CRT screen showingthat the device is busy.

Each of the data sent to the computer is a numeral smaller than 2000.

The resolutionof the digitization is 0.1 nA at the most sensitive measurements. The time necessary to receive the data for eachdirection is about 59 seconds: la bout 9 seconds for moving the probe to the starting position of the measurements,and 50 seconds for the measurements at the 19 positions.

After the measurements are completed, themicroprocessor can receive the command D6 and send the data to the computer.

It cannot start another sequenceof measurement before the probe returns to the initial position, which takes additional 58 seconds. The command
XY triggers successive measurements in the x- and y- directions. There is one power supply for the two pulse
motors to move the two probes, and it must be switched over when the probe is changed, which takes about 10
seconds. Therefore it takes 174 seconds to receive the data in this case and 229 seconds to start anothermeasurement.
After the computer receives the data, it temporarily stores them in a disc file.
them for the numerical processing and displays the result on a graphic CRT.
examples of the diagrams on the CRT.

Then another program uses

Figure 3(a) and (b) show theThe data were taken for 315 keY Nl+ beam at the injection line.

References
1)

M. Saito, I. Yokoyama, M. Kase, T. Kambara, and M. Odera: IPCR Cyclotron Progr. Rep., !±, 138 (1980).

2)

T. Kambara, S. Takeda, and M. Odera: ibid., p. 110.

144

N -10.

Single Arm Motor-Driven Slit System

T. Chiba and M. Odera

In the beam steering procedure through the accelerator or through the beam transport systemof the accelerated ions, it is frequently desired to be able to adjust remotely the width of the slits
at several locations along the course of the beam. On the other hand, there are many cases where
no need is felt to fix the adjustable slits permanently to each location. After suitable prescriptions
are established for beam manipulation around the position, the slits may be removed or replaced bysimpler slits. Therefore, installation or removal of them should be simple. Sometimes, however,the space around the beam pipe is not enough to set the motor and driving mechanism on bothright and left sides or above and below the slit-box. A simple and space-saving mechanism must be
devised.
Figure I shows the slit system we have constructed to answer the requirements. In the
Figure, a motor drives two opposite blades of the slit in the inverse directions at one time by
11

Off set

Cooling pipe\
/ Fla nge of probe box
In sul at ort~

Mot or and -/I

LR~~~Rni~\;'

I nsulator

Fig. 1.

Cross section of the motor-driven slit system.

145

rotating a shaft which has a right-handed screw cut on its half length and a left-handed screw on
the other half.
two blades.

Therefore, only one side of the slit box is occupied by the driving motor to move

Vacuum seals of the moving parts have welded bellows.

The slit system is machinedcarefully so that the center of the slits or the closed position of the blades coincides with thecenter of the probe box accurately. The two blades move always symmetrically about thisposition. There is also an adjusting screw to allow shift of this position by a small amount. Eachblade is cooled separately by circulating deionized water through the stem and the cylinder
supporting blades. The axis of the driving shaft is offset from the center of the vacuum flange,
so that two such slit assemblies can be inserted into the same probe box through the vertical andhorizontal ports. The two pairs of slit together define a remotely adjustable rectangular window
to the beam.

146

N -11.

Simple low-Cost Profile Monitor

M. Hemmi and I. Yokoyama

A profile monitor which measures the transversal intensity distribution in the beam crosssection is a valuable diagnostic tool for operation of any accelerator. In our linac, many profile
monitors are also necessary along the beam line , i.e. , on the injection beam line, between thecavities , and on the beam transport line in the experimental areas.

Monitors of low cost, simple

to use and reliable in operation are required to fulfill the demand.
Figure I shows the structure and way of use of the monitor we designed.

The horizontal andvertical wires which sense the beam current are moved by a pneumatic actuator and scan the beamswiftly. Diameter of the wires is 0.2 mm. Signals are amplified by the head ampiifiers set neareach monitor, sent to the controle room and displayed on a memory oscilloscope in the operator'sFig. 1.

Two-wire beam profile monitor.

By thrusting thesensors in the direction making fourty-five degrees withrespect to the horizontal plane , current densities in X andY directions are measured easely within a few seconds.
is driven by a pneumatic cylinder.

It

147

console. The sensitivity of the amplifiers are adjustable remotely from the control room by four
decades. Wider range of sensitivity is obtainable by locally attaching current shunt resistor to theamplifiers. Positions of the wires in the aperture of the beam pipe is given by an encoder made ofa conductive plastic potentiometer mechanically coupled to the rod of the pneumatic actuator.
The signal wires from the monitors in the various locations are connected to a switcher circuit in
the control room. The interface circuit can receive up to 31 signals. Figure 2 shows the signal
processing scheme schematically. Selection of the monitors to be displayed is made remotely byuse of a microprocessor whose control sequence is given by a program written in its EPROM.
Table I shows the specifications of the monitor.

Fig. 2.

Scheme of measurement and display.

Table 1.

An example of the beam
Fig. 3.
profile at the entrance of first cavity.

Specifications of the profile monitor.

Maximum sensitivity: 5 X 10- 11 A per div. of CRT vertical scale
Response time of the head amplifiers: 5 msec in rising up to 90 % of the maximum
Drift of the amplifier system: less than 2 X 10- 11 A
Scanning area: 70 mm</>
Maximum error in position: less than 2 mm
Time required for single measurement: a few seconds (between 0.5 - 3 seconds)

148

N -12.

Beam Attenuation by Slit with V-Slots

M. Yanokura, T. Chiba, and M. Odera

Sometimes attenuation of beam by a large factor or formation of beam profile of very small
diameter is necessitated.

For instance, direct measurement of the beam energy by inserting asolid state detector into the beam path is required, in the tuning process of the linac, to find out
if there exist some impurity ions mixed.

In such a case the intensity of the beam must be greatly

decreased in order not to destroy the cystalline structure of the silicon detector by heavy
bombardment.

Another example is the use of a beam of fine diameter to examine the complex

structures of some materials such as the texture of alloys or structure of biological cells.
Figure 1 shows the cross section of the slit system .

The overall structure resembles that of

the motor driven slit system except a V-slot is cut in each blade and pulse motor is used to allow
ajustment of the slit gap in fine steps.l)

Also the two blades are attached to the supporting stem

and cyl inder in such a way that the blades never collide with each other and the paired V -slots canform a small rectangular opening of only several micron in width when the heavy-ion beam is used.
Probe box
Welded bellows

Pu lse motor

Fig. 1.

Cross section of the beam attenuator.

Reference
1)

T. Chiba and M. Odera: p. 144 in this report.

149

Status of the RIKEN Separated Sector Cyclotron ProjectN -13.

H. Kamitsubo

The project for a separated-sector cyclotron (SSC) with K = 540 started at Riken in 1980.
The SSC was planned to be an energy booster of the RILAC for acceleration of heavy ions. It
will have another injector for light-ion acceleration and an AVF cyclotron with K = 90 will be
installed for that purpose. A customary diagram of energy vs mass number for the present SSC isgiven in Fig. I together with those of the major facilities now under construction in the world.
The ordinate gives the energy per nucleon as usual. The solid line labelled IPCR shows the
maximum energies of ions when they are produced by a conventional PIG source, while the dottedline presents the expected maximum energies when ECR sources will be installed at the injectors.
Typical examples of the operating parameters at the maximum energies of ions in the RILAC-SSC
and the AVF-SSC combinations are listed in Table 1.

Charge number, q2' for the SSC corresponds

to that of the optimal charge state after the ions pass through the foil strippers which will beplaced between two injectors and the SSC.
The design study of the SSC is well in progress. Calculations of beam dynamics in the SSC
have been extensively carried out. Computer codes for the calculation of the equilibrium andaccelerated orbits, for the ray tracing calculation of the injection and extraction trajectories and forthe simulation of the effects of harmonic field and defect in the isochronous field distribution in
the SSC were newly developed.
It is recognized that the acceleration on the well-centered orbits is very important to get thebeam of good quality. Conditions for well-centered acceleration were studied analytically and were

200 --- ..... ,",NSCL II.... ....

' ....

' ....

", ,

",

z

.... GANIL
,

0

,

W
...J
()

.... ,

,

:::J
Z

"

,,

,,
"

">-

'-'
0: 20
w
z

,

",,

""

Fig. I.

"".... ,"".

w

Maximum beam energy vs.

mass number of the RIKEN SSC
together with those of heavy-ion
accelerators now under constructionin the world.
GANIL: Grands Accelerateur

10

Nationale de Ion Loudes.
40

80

120

160

200

MASS NUMBER240

NSCL: National Superconducting
Cyclotron Laboratory (Michigan)

150

Table 1.

Examples of operating parameters at the maximum energies
in the present accelerator complex.

~
Linac

SSC

40Ar

84kr

132Xe

238U

Charge ql

8+

9+

9+

10+

m/ql

5

9

15

24

FAce. (MHz)

43.3

33

26

20.4

E(MeV/u)

3.8

2.2

1.36

0.84

Charge q2

15+

24+

30+

37+

m/q2

2.7

3.5

4.4

6.4

B1nj (T)

1.45

1.45

1.43

1.64

B Ext (T)

1.55

1.5

1.46

1.66

FOrb. (MHz)

4.8

3.67

2.88

2.27

FAce. (MHz)

43.3

33.0

26.0

20.4

h

9

9

9

9

E(MeV/u)

66.6

36.8

22.3

13.6

p(H 2 )

3He

12C

Charge ql

1+

2+

4+

m/ql

2

l.5

3

FOrb . (MHz)

7.37

7.37

6.51

22.1

22.1

19.6

BExt (T)

0.97

0.727

1.28

E (MeV/u)997Charge q2

1+

2+

6+

m/q2

1

1.5

2

B 1nj (T)

0.833

1.26

1.48

~xt (T)

0.994

1.49

1.67

F Orb. (MHz)

7.37

7.37

6.5

F Ace. (MHz)

44.2

44.2

39.1

6

6

6

184

184

134.6

~
Cyclotron

FR F

SSC

(MHz)

h
E(MeV/u)verified by numerical calculations. According to these, the matching of the beam profile in the six
dimensional phase space at the injection point should be well realized by adjusting the parametersof the beam transport line for injection. An alternative and more practical method was developed
to use the first order harmonic field for bringing the injected beam onto the well-centered orbit.

151

Two of the sector magnets were ordered to Sumitomo Heavy Industry Co. The final designof the magnets was finished in last June after extensive calculations by the computer code TRIM
and field measurements on the 1/4 scale model magnet. Number of the trim coils and the shapeof their winding were so determined that the difference between the actual and ideal isochronous
field distributions can be reduced to give no significant effects on the beam quality in the SSC.
The first sector magnet will be completed at the end of next March and the second one in June.
Field distributions inside the gaps of the magnets and in the valley region between both magnets
will be measured next summer. Then the calculations of the beam dynamics in the SSC will be
pursued again by using the measured field maps. The final design of the injection beam line will
be done after that.
There will be installed two bending magnets, two magnetic inflection channels and anelectrostatic inflector to bring the beam to the injection point in the SSC. A bending magnet isplaced very close to the sector magnets. It should produce magnetic field up to l. 7 5 T and should
be as small as possible.
measured.

A full scale model was made and its performance characteristics were

Design of the RF cavity is also in progress.

It was decided that a half wave length resonator

will be adopted for the RF system of the SSC. Characteristics such as resonance frequency, RF
voltage distributions along the accelerating gap and the quality factor were measured for the halfscale model. In order to analyze numerically the fundamental characteristics for cavities of thevarious shapes, a computer code has been developed to solve the Maxwell equations directly inthree dimensional case.
Design of the vacuum system has been pursued during the past year. The chamber will be
devided into eight sub-chambers and seals between them are amongst the most critical vacuum
components of the SSC. Because of the space limitations, pneumatic seals will be adopted as
vacuum seals between sub-chambers. Three 1/3 scale model of the pneumatic seal were made andhave been tested to determine their performance characteristics.
Layout of the experimental area and the beam transport system was almost fixed. Radiation
shielding has been extensively studied for the proposed layout. The beam transport lines to theexperimental halls were designed to bring the beam in the achromatic or highly dispersive modes,
and also in the isochronous mode. Detailed calculations of their characteristics were made using
the computer code TRANSPORT.

152

N -14.

Some Results Obtained from Orbit Calculations

N. Nakanishi , A. Goto, and Y. Yano

Orbit calculations for beam dynamics in the RIKEN sse have been done to study acceleratedbeam properties.

Some results are presented on the resonance effect in focusing frequencies, theimperfection effect in isochronous fields, and the effect of dee angle on the acceleration efficiency.
Focusing properties for various particles to be accelerated in the sse are examined in the
betatron frequency space.

The sector angle of 50° was determined so as to give optimum focusing

to various particles in the space . A 9 MeV proton beam , however, crosses two resonance lines:
v r = 2 vz and 3 vr = 4.1) It is known that the former is a quadratic, non-linear, coupling resonance,
and the latter a quadratic, non-linear, intrinsic resonance in the four-sector sse. The proton beam
encounters these resonances at energies of about 128 MeV and 165 MeV.

Radial and axial half

widths of the beam on the mid-line of an open valley are shown in Fig. 1.

Only a slight change

in width is observed through the acceleration process .

The behavior of the phase space patterns

at the vicinity of the vr = 2 vz (Walkinshaw) resonance is also examined , but harmful distortion in
the patterns was not observed. According to these facts the influence by these resonances on
beam qualities is considered to be very small at least in the case of 20 mm . mrad emittance.

It isconsidered that the influence of these resonances is small because of a large energy gain per turn.
The influence of imperfection in isochronous fields has been investigated again .2 )of isochronous field are adopted: a concentric type and a Gordon type.

Two types

The concentric-type

isochronous field which is calculated by program EQUIOT 3 ) is formed by multiplying a factor to
the base field along a concentric circle which corresponds to a concentric-type trim coil.
4

Wal ki nshaw

Vr = 3"The

vz= 0.5!

5.0

I:.·....................................:.:. .:.....................:..........:. :......... ... -... .....

x

x

x

)(

x

x

x

x

x

XXXX)(XXX

x

x

x

x
x

2.5

x

x

X

x

x

x

x

~

-

E E
E E

~

x

N

o0

80

40

<l<l

200

160

120

( Turns )x- 2. 5
x

)(

X

x

x

x

x

x

x

x

x

x

)(

x

X

x

X

x

x

x

x x

x x x x- . i·· .

5 0 • • •• ••••• •••••••••

Fig. 1.

... ••••••••••••••• . .

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

Radial (.) and axial (X) half widths of 9 MeV proton beams.

153

Gordon-type field is form ed by multiplying a factor to the base field along a certain line whichcorresponds to a Gordon-type trim coil. In the magnet region the line is a beam trajectory in a
hard-edge approximation, and in the valley region it is a line normal to the magnet edge at theintersecting point of the edge with the trajectory.
The Gordon-type isochronous field is calculated by program EQUI 2. 2 ) The program has beendeveloped to get a Gordon-type isochronous field and to look for equilibrium orbits in that field .
In order to estimate the influence of imperfection in each isochronous field, sinusoidal field
perturbation which will be made by both types of trim coils are superimposed on the isochronous
field. Energy spreads in a beam and phase slips of the central beam were calculated for various
amounts of field perturbation and various wave length. Energy spreads show a similar tendency inboth cases. It oscillates in the range between 2 X 10 - 4 and 5 X 10 - 4 at the field deviation ofless than 0.13 %. The oscillation of the phase slip is fairly well leveled in the case of theconcentric-type field, but in the case of the Gordon-type one it is straight-forwardly connectedto that of imperfection in the amplitude and the wave length. Since the aspect of the energy
spreads is considered to depend on the magnetic field configuration, the type of trim coils should
be chosen so as to minimize the possible energy spread in the four-sector sse. According tothese calculations, it is supposed that the Gordon-type trim coils will be more suitable in the
RIKEN sse.
The angle of the delta-shape accelerating electrode was preliminary taken to be 20°, because
the fundamental harmonic number h = 9. It has been confirmed that the choice is not wrong inview of stability in the phase space. In case of the sse composed of four sector magnets, it isclear that the angle of 20° is not most efficient in the energy gain per turn, since an equilibrium

880t~48Mevc"

870
3370
33 60

200 MeV U40 -

3350

>
Q)

L
>,

33 40
1850

~
Q)

c

w

84Me V C6 -1
1 800
1 750
1 700
220
210
200
190
I

19

20

21

Dee An gle

22( degs .)23

Fig. 2.

Attainable energy versus deeangle for four injected beams.

154

orbit has a squared shape.
most suited angle.

Therefore, a numerical calculation was made in order to obtain the

Figure 2 shows attainable energies for four typical beams of 48 Me V C6 +, 200

MeV U40 +, 9 MeV p+, and 84 MeV C6 + at the turn numbers of 140,80,230, and 330, respectively.
An accelerating voltage is assumed to be 250 kV.
that of the others is 6.

The harmonic number of the first two is 9 andIt may be seen that the angle of 21.6° is most efficient.

The change

from 20° to 21.6° of angle brings about energy-gain increase of 0.8 % and 5.5 % for eachacceleration mode.

Accordingly the turn number can be reduced.

Extensive examinations are now

in progress.

References
1)

N. Nakanishi, A. Goto, Y. Yano, and T. Wada: Proc. 9th Intern. Conf. on Cyclotron andtheir Applications, Caen (1981).

2)

N. Nakanishi, A. Goto, and Y. Yano: Sci. Papers I.P.C.R.,~, 136 (1981).

3)

N. Nakanishi: Reports I.P.C.R., (in Japanese), 57 , 189 (1981).

155

N -15.

Formulation of Beam Centering Equation ina

Separated Sector Cyclotron

Y. Yano, A. Goto, and N. Nakanishi

In order that a beam of good quality can be extracted from a separated sector cyclotron (SSC),
the beam should be accelerated along a well-centered orbit inside the sse. This well-centered orbit
acceleration can be achieved when the central particle of the beam moves in the sse as shown in
Fig. 1. The essential feature of the motion is that the particle crosses the equilibrium orbit (E.O.)
corresponding to its kinetic energy every time it reaches the mid-line of open valley, e.g. points A
and D. R(i) and R(i + I) represent the radial distances measured from the machine center to thei-th and (i + 1) -th E.O., respectively. In the case of a single-gap acceleration system, the particle
would reach point B and leave the same point after gaining the energy. In our double-gap
acceleration system, however, the particle is deflected by the accel. gap I and then is inflected by
the accel. gap 2 as shown in the inset (Fig. I). Because these deflection and inflection angles arealmost the same, the treatment of this double-gap acceleration process can be simplified by describing
the process in such a way that the particle reaches the point B and then leaves the point C after it
gains the energy which is to be obtained by the passage of two acceleration gaps. The radial
shift of the point C from the point B is given by E(i).
Now let us consider the motion of the well-centered particle mentioned above on the radialphase space.

The fact that eigen-ellipses for a certain E.O. given at mid-lines of four valleys are

identical and they are erect ellipses makes the description much simpler.

We can transform these( i + I) - th E, 0 ,i-th E,O./

R' (i - th E. 0 . )

a (i)

A

R' (i+l-th E.O.)Da(i+l)R-

D(R( i+l))----

R(i+l)

Fig. 1.
Well-centered acceleration
orbit (thick solid line). A particle
moves clockwise and is accelerated
by a couple of gaps in one dee (seethe inset). The i-th and (i + I) -th
equilibrium orbits are also drawn.
Leave the details to the text.

Fig. 2.
Diagram describing motion of awell-cen tered particle on the radial phasespace. Points (A-D) correspond to thosein Fig. 1.

Leave the details to the text.

156

ellipses into circles by multiplying an appropriate scaling factor to the values of angular divergence.
This factor is given by ro Ir o', where ro (radial displacement) and r o' (angular divergence) represent
the principal axes of the ellipse.
Figure 2 shows the diagram describing the motion of the well-centered particle on the radialphase space. The left (right) vertical axis (R') gives the angular divergence for the i-th ((i + l)-th)
E.O. which is properly scaled.

The horizontal axis (R) represents the radial distance from themachine center to the E.O. of interest at the valley mid-line.
considered.

This axis is common to all the E.O.

The particle which leaves the point A with the energy of E(i) and the angulardivergence of a(i) moves along the circular arc AB and reaches the point B. Then it gets theenergy gain of 6E = E(i + 1) - E(i) and the radial shift of e(i) by the acceleration system.
Afterwards the particle moves along the circular arc CD and reaches the point D.

v(i) andv(i+ 1) represent the radial betatron frequencies for the i-th and (i+l)-th E.O., respectively.
From the diagram shown in Fig. 2, we can formulate an expression, which will be called"beam centering equation", for getting the well-centered acceleration orbit.

This equation can be

written in the form of
-z[

1
+
1
tan [; { v ( i) - 1 }]tan [; { v ( i + 1 ) - 1 } ]+c:(i)=R ( i+l ) -R ( i )(1)with z indicated in Fig. 2. We assume that the trajectory between a couple of acceleration gaps
can be approximated by a straight line and also that it cuts the mid-line of dee valley at right angles.
These are fairly good assumptions because the magnetic field in the dee valley region is very low.
Further, we assume that the particle crosses the mid-line of dee valley at the moment the RF
voltage becomes null.

Then we can get the following expressions:~E=2g ( l ) qV{R*seC ( fJdee/2 ) } sin ( !:lfJ ) / !:lfJ,(2)~ fJ = g (2) I R *,(3)c: ( i ) = g (3) {~E / 2E( i)} R*,(4)

R * = R ( i) + a ( i) sin { ; v ( i) }(5)z = a ( i ) cos{1- v ( i ) } ,(6)gO); g(2), and g(3) being given by use of the geometrical parameters for the sector magnets and RF
resonator and the harmonic number of acceleration. q is the charge number of the particle, 8 dee
the dee angle and Vex) the RF voltage given as a function of x, the distance measured along the
mid-line of dee gap from the machine center. The term sin(68)/68 in Eqn. (4) is introduced totake into account the transit-time effect due to the finite acceleration gap.

157

N -16.

Beam Centering and Related Problems inaSeparated Sector Cyclotron

Y. Yano, A. Goto , and N. Nakanishi

We used the beam centering equation 1) to determine the conditions for centering the beam
injected into the separated sector cyclotron. In applying this equation, the first condition is thata central particle of the beam must be injected at the radial position R(1) at an appropriate RFphase. This phase is calculated by the first-order transformation matrix theory. The second
condition is that the central particle must be injected with the angular divergence given in thefollowing way.
Assuming that v( I) = v(2) and R * = R( I) , the expression to obtain the necessary angulardivergence a* (in actual unit) at injection point is deduced from the beam centering equation.
This is written asa * = {R ( 2) - R ( 1 ) - c ( 1) } ( r 0' / r 0) {2 s in ( ; v ( 1 ) ) } .

(1)

The right-hand side of Eqn. (I) is calculated from the isochronous field data and given RF voltage
distribution of Vex).
The calculation of beam centering of 12c6+ with the injection energy of 50.57 MeV was madeas an example.

We used the RF voltage distribution shown in Fig. I.

taken to be 250 kV.

The voltage at R iI1j was

A fairly good result was obtained that the orbit center is injected onto thecircle of radius of about 0.3 mm. Figure 2 shows the transformation of beam properties with theradius calculated by tracing four particles together with the central particle. These four particles
exist on the eigen-ellipse of emittance of 20 1T mm ·mrad at injection point.
matching 2 ) was made.

The CP phase

The time-varying magnetic field 3 ) induced by the radial distribution of RF
Fig. 1.
Radial distribution of RF voltage
used in the calculations of beam centeringof 12C6+ with injection energy of 50.57
MeV. R represents the distance measured
along the mid-line of dee gap from themachine center.

normalized by the voltage at the position(Rinj ) of the first acceleration orbit.
The dashed curve shows the voltage
distribution obtained by the presentv
V i nj1. 67 -- ------------ - -- - - - - --- - - ----- -:.;:.--;- -,--_ __1.0- - - -------11

The RF voltage is_structure of RF resonator and the solid- -curve the resultant distribution calculated
so that the beam centering equation can
0.0- - - - - ' - - - < - - ' - - - ----'-- - " - - - - - - ' -_ _.1.....-_

o

3

R(n)

hold throughout the acceleration regionof the SSC.

158

voltage was also taken into account.
Secondly, we calculated the RF voltage distribution which makes the beam centering equation
hold exactly throughout the acceleration region. This distribution can be obtained by solving theequation iteratively by use of the isochronous field data.
is shown in Fig. 1 (solid curve).
about 0.1 mm.

The resultant RF voltage distribution

In this case, the orbit center moves along the circle of radius of

Figure 3 shows the transformation of beam properties calculated by using thedesired distribution.

It can be seen that the energy resolution and the beam emittance at

extraction point are improved considerably.
BERM HISTORY lIElIElIElIElIElIE BERM HISTORY lIElIElIE
R
Z =

E =
R =
RlIE =
<!>
=

R
Z =
E =
R =
RlIE =<!>=

126
50.750 MEV
84 . 837 eM
18.6 6 1 MR
80.567 OEG

:L

12
6
50 . 750 MEV
8 4 . 837 eM
11.58 1 MR
84 .1 41 OEG~L:I~ : I~~
~o :1

~o:1

~

~

~ :1
~ :1
l ~I'- - - - - '- - '- - ce=- - '- - -= - - - -L- -~ N~o~L-1--------L....J~L - -- - - - - - - ' - - - - - - ' - _-----'---------------'----

L - -- - - - - - - ' - - - - - - ' - _ - - - - - ' - - - - - - - - - - - - - - - ' - - - -

_

100

20 0

R ( eM

300

400_ _ ' _ _ _ _ _ _ ' _ !_200

R ( eM)

Fig. 2.
Transformation of beam
properties (radial emittance, full radialwidth, full phase width and energy
resolution) calculated at the mid-line ofopen valley.

100____'_

300

40 0

)

Transformation of beam
Fig. 3properties. Calculations were madeusing the RF voltage distribution givenby the solid curve in Fig. 1.

Calculations were madeusing the RF voltage distribution given by
the dashed curve in Fig. 1.

References
1)

Y. Yano, A. Goto, and N. Nakanishi: p. 155 in this report.

2)

W.M. Schulte: "The Theory of Accelerated Particles in AVF Cyclotrons", Thesis, Eindhoven(1978).

3)

W. Joho: Particle Accelerators, 6, 41 (1974).

159

N -17.

Design of Injection and Extraction Harmonic Coilsfor the RIKEN SSC

A. Goto, Y. Yano, and N. Nakanishi

Harmonic coils for the sse were designed for beam centering in the injection region and forbeam off-centering in the extraction region.1) Using the numerical calculation programs ,2) the
behavior of the orbit centers under the influence of the first harmonic field perturbations producedby these coils were investigated, and their optimal parameters were searched for.
It may happen that off-centering of the beam in the injection region occurs from following
two causes: field distortion due to the injection elements and incorrect setting of these elements.
Accordingly a harmonic coil is necessary to produce a magnetic field perturbation in the injection
region in order to center the beam during the first several turns.

In the extraction region the

beam separation due to only acceleration is not enough for some of high energy light particles (e.g.
134 Me Vlu 12e6+). A magnetic field perturbation will also be required to enhance the turnseparation in order that the single turn extraction can be achieved.
In surveying the beam behavior it is often convenient to calculate the motion of an orbit
center instead of a particle itself.

In the present calculation, the first harmonic field wassuperimposed onto the base field (isochronous field) and the motion of the orbit center was
deduced by tracing a beam in the resultant field.

The azimuthal distribution of the harmonic

field, for example, which was used in the calculation is shown schematically in Fig. 1.

Fig. 1.

Azimuthal distribution of thefirst harmonic field used in the calculation(solid line).

It is desirable to center the beam during about five particle revolutions or so, whichcorrespond to a half turn of the orbit center (v r - 1 ~ 0.1).

For this reason we decided to divide

all kinds of particles into three groups according to their orbit separations and to center them by
three sets of harmonic coils, respectively.

Thus we chose a typical particle for each group andcalculated the motion of its orbit center in the presence of first harmonic field perturbation.

They

are 7 Me Vlu 12e6+ , 4 Me Vlu 12e6+ , and 0.84 MeV lu 238U40+ , whose orbit separations are smallest,,m edium and largest, respectively, among all the ions accelerated in our sse.

An off-centered

beam was artificially given by putting the beam onto its equilibrium orbit at the injection point.
The calculations were done using the code INJHARM. 2) The optimum positions of the three setsof harmonic coils were found to be at Rh (the radial position on the hill center line) = 101.5,
113.5, and 125.5 cm.

The widths of these coils were taken to be 11.5 cm.

In Fig. 2 is shown,as an example, the motion of the orbit center for the 0.84 MeV/u 238U40+ beam, which was
calculated in the harmonic field produced by the outermost coil.

The dots stand for the orbit

160

Y( MM JY(M Ml

SP
j 5

10

-15

-1 0

10

-5

10

15

-15

-1 0

-5

15

X(MMl

X(MMl
-5

1S T HRRM.

- 10

- 15

-10

-15

1ST HRR M.

Fig. 2.

Motion of the orbit center

Fig. 3.

Motion of the orbit centerfor the 0.84 MeV/u 238U40+ beam

for the 134 MeV/u 12C6+beam inin the injection region under thethe extraction region under the

influence of the first harmonic field.

influence of the first harmonic

The injection point is on the x-axis.

field.

The dots stand for the orbit centers

positioned at about IS°.

and SP their starting point.

stand for the orbit centers.

The entrance of EDC iscenters and the azimuthal position of the injection point is set to be 0°.

The dots

One can see that theorbit center starting at the position about 15 mm apart from the cyclotron center is centered after
about five particle revolutions.

The strengths of the harmonic fields (and the azimuthal positionsof their maximums) which are needed for centering the three beams were 10 Gauss (260°) , 12
Gauss (255°) , and 24 Gauss (250° ), respectively.
We aimed to extract a beam before vr = 1 resonance in order to avoid the strong radial
defocusing of the extracted beam due to the fringe field of the sector magnets.

The study wasconcentrated on the extraction of the 134 MeV/u 12C6+ beam (the injection energy of 7 MeV/u)
whose orbit separation is the smallest among all kinds of accelerated particles.
made using the code EXTHARM.2)

The calculation was

At first the well-centered orbit of the 12C6+ beam wascalculated using the code ACCEL 2) from the injection point up to the region where its radial
distance is less than the extraction radius (373 cm on the hill center line) by about ten revolutions.
The orbit center continues to stay at the cyclotron center during this acceleration.

The beam

parameters thus calculated were inputted into the code EXTHARM and then the parameters of theharmonic coil - its radial position, its field strength and direction - were searched for in order toobtain the beam separation large enough for single turn extraction.

The optimum position of thisharmonic coil was found to be at Rh = 372 cm, which is just inside the extraction radius.

Theorbit separation becomes larger, the steeper the field rise is; thus the narrower harmonic coil ismore desirable.

It was decided, therefore, to use the coil of 1.2 cm in width, which is made of acopper hollow conductor.

Figure 3 shows the motion of the orbit center for the 134 Me V /u

12C6+ beam, which was calculated in the first harmonic field produced by this coil.

The dots

stand for the orbit centers and the azimuthal position of the extraction point is set to be 0° .
entrance of the electric deflection channel (EDC) is positioned at about 15°.

The

One can see that the161orbit center which stayed at the origin begins to move toward the entrance of EDC. The
maximum displacement between two successive orbit centers is about 5 mm. In this case thestrength of the field and the direction of its maximum are 100 Gauss and 205°, respectively. In
Fig. 4 is shown the result of calculation of the transformation of beam ellipses on the valley centerline (at 0°) with and without the first harmonic field mentioned above. It can be seen that thebeam envelopes which were in contact with each other in the case of only acceleration can beseparated with this harmonic field by about 5 mm at the extraction point. The septum of EDC
will be located between 308th and 309th revolutions.
Further, we also use another harmonic coil of the same width just inside the above determinedcoil as an auxiliary one.

Its radial position is at 370.6 cm.

These harmonic coils are also used as part of trim coils which consist of 29 pairs. Figure 5
presents the plan of the trim and harmonic coil set. We use three coils from No.5 to No.7 asharmonic coils for beam centering and two coils, No. 26 and No. 27, for beam off-centering.
Coils numbered less than 8 are wound around the nose of the pole tip and the others around
its back.
5.0
4.0
3.0
2.0

@)

5.0
4.0
a. 3.0
2.0
1.0

QQ9>

1J

"'

\...

0~0\) 0\) 0 <) I:)

E
tJ

~
I

~

330

°0

@)

0~0\)0u0~ \l1D ~QlfJ~

331

(a)

332

333

334

335

336

(b)

337

r (c m)Fig 4.
Radial phase space envelopes at 0° for the
134 Me V lu 12C6+ beam in the extraction region, (a)with and (b) without the first harmonic field. The
numbers refer to the revolutions of the beam. The
beam emittance is taken to be 20 mm. mrad at theFig. 5.

Plan of the trim andharmonic coil set for the
RIKEN SSC.

injection point.

References
1)
2)

A. Goto , Y. Yano, and N. Nakanishi: Sci. Papers I.P.C.R., 75, 204 (1981).
A. Goto, H. Takebe, S. Motonaga, T. Wada, Y. Yano, N. Nakanishi, and Y. Tanaka: Reports
I.P.C.R., (in Japanese), 57,165 (1981).

162

The Sector Magnet for the RIKEN

N -18.

sse

S. Matanaga, H. Takebe , A. Gata , J. Fujita,
T. Wada, Y. Oikawa, 1. Takeshita, and Y. Ikegami

The design of the sector magnet described in the previous progress report 1) was changed slightly.

Moredetailed design work for the pole profile , configuration of the trim coils and vacuum seal between magnet andRF-cavity have been done during the year.
The profile of the m agnetic field distribution should be such that the field will provide isochronism , focusing
and orbital stability for the beam .

Table 1 lists the final design parameters of the sector magnet.

magnets will produce the magnetic field of 15.5 kG at maximum.

The four sector

The maximum magnetomotive force wasestimated to be 1.35 X 105 A·T and the maximum power consumption in the four sector magnets is estimated to be
450 kW.

The shape and geometrical size of sector magnet are shown in Fig. 1.

Table 1.

Extremely tight tolerance limits

Characteristics of SSC Magnets.

Number of sector magnet

4

Maximum magnetic field

15.5 kG

Sector angle

50°

Maximum magnetomotive force

1.35 X I0 5 A-T

Gap width

8 cm

Maximum current

1000 A

Injection mean radius

89.3 cm

Current stability

0.002 %

Extraction mean radius

356 cmMaximum power

450 kW

Height of magnet

5.24 mNumber of trim coils

29 pairs X 4

Radial length of magnet

5.64 mMaximum current

500 A

Total weight2] 20 ton

Current stability

0.05 %

Total trim coil power

200 kW(530 ton/ one sector)

,
1

I

1,

I

,

I
55

1

~ L'"~:;;1~I ;;;

,

~
~

~

I

~

~

T ~l

,

~

I

,~~

I

1420
,...---_ __ _ ~6290

I

Lill... ~~1980

Fig. 1.

Shape and geometrical size of thesector magnet.

163

are imposed on the magnetic field to obtain a high quality beam.

The specified tolerances for the field stability,

accuracy of machining and alignment for the construction of the magnet are as follows:
Stability of the magnetic field
10- s
Maximum deviation from the isochronous field

10-4

Relative error in gap distance of the four sector magnets

0.02 mm

Error in parallel setting of pole face
Sector angle

0.05 mm
50 00° +0 .02

Misleveling of the four sectors magnets

0.1 mmError in positioning of the four sector magnets

0.1 mmError in parallel setting of trim coil assembly

1.0 mm
± 0.5 mm.

Error in positioning of the trim coils assembly

0

-0.00

The poles are triangular in shape with sector angle of 50° and length of 3.297 m along the center line.

Thepole-edge profile of side part in azimuthal direction was a modified B-constant type. Detailed design of the poles
was performed on the basis of calculated magnetic field as well as measured field of the model magnet. The sideof the central part as shown in Fig. 1 are cut away slightly to keep a wider space between the magnet andRF-resonator.

Change of the effective boundary by this modification for this part was found to be small.

The yoke was divided into 16 slabs with maximum thickness of 340 mm for the convenience of theconstruction and transportation.

The ratio of cross-sectional area of yoke to that of the pole base was 0.94.

Very homogeneous forged steel with carbon content of 0.01 % was used for the pole and rolled steel of0.04 % carbon contents for the yoke of each magnet.
single ingot.

Table 2.

Pole

Yoke

Fig. 2.

Two poles of each sector magnet was prepared from a

Table 2 shows measured characteristics of the steel used.

{fl

Measured characteristics of the low carbon steel (weight percent).

C

Si

Mn

P

S

Cu

Al

0.01

0.001

0.08

0.013

0.002

0.01

0.018
0.036
0.031

0.01

0.001

0.09

0.011

0.003

0.01

0.01

0.001

0.10

0.011

0.002

0.01

0.04

< 0.01< 0.01

0.31

0.14

0.30

0.10

0.04

Pole plate of the first magnet duringmachining using NC-machine.

Fig. 3.

Yoke slab of the first magnet during fabrication.

164

Fabrication of the first magnet started in July, 1981.

Figures 2 and 3 show pole and yoke parts duringmachining.
The Main coil of one pole consists of 66 turns of hollow copper conductor for direct water cooling and madeup of 11 units with 6 turns.

They formed in size of 5.0 cm in thickness and 46.5 cm in height.

Tape-winding

with glassfiber reinforced epoxy resin was ,used for insulation between turns and to provide mechanical strength.
Figure 4 shows the main coil of the first sector magnet.

The main coils are located outside of the vacuum

chamber.
Mechanical deformation of yoke and poles due to the magnetic force, gravitational force and atmosphericalpressure was calculated by a computer code FEM-2,3)

The maximum deformation of 0.15 mm for pole face andvertical displacement of 0.25 mm at the front of pole tip were obtained.

By applying 1 mm thick gap spacer

between pole base and yoke, we could reduce the deformation to 0.1 mm, but the value of the vertical displacement
was increased to 0.35 mm.

Such displacement will entail no problem on the beam dynamics.

For forming the required isochronous field, 29 pairs of trimming coils will be mounted on the pole face.
5 pairs of them will also be used for the harmonic field formation.

The radial width and positions of the trim

coils were determined by using a computer optimization code developed by Goto. 4 )trim coils configuration is shown in Fig. 5.

The detailed design of the

Trim coils consist of 6 mm thick copper plate and cooled by 6 X 12mm hollow conductor welded to the copper plate.

Each coil is flash-coated of fused aluminum oxide.

Figure 6shows one of the copper plate coated with Al i 0 3 .

Fig. 4.

Main coil of the first magnet.

Fig. 5.

Layout of the configuration of thetrim coils.

Fig. 6.

Copper plate coated withaluminumed oxide.
The trim coils will be mounted directly on the pole face by bolts and enclosed with an auxiliary vacuum
chamber.

In order to reduce the magnetic perturbation due to bolt holes on the pole face, special bolts of softiron welded onto stainless steel will be used.

Cross-sectional view of the pole section is shown in Fig. 7.

The final design of equipment to map the field of the sector magnets was completed.

This system employs

165

Fe

T rim co il co ver

Fig. 7.

sus

Detailed cross-sectional view of the pole edge section .

21 Hall probes radially arranged, which measure the magnetic field between minimum and maximum radius as a0function of the azimuthal position in the range of 360 with stepping mode.

Operation of this system will becontrolled by computer.
Fabrication of the sector magnets are progressing satisfactorily at present.

In order to finalize the polecontour, preliminary measurement of edge field in the azimuthal direction will be performed at Sumitomo Heavy
Industry's Work Shop in April, 1982.

References

1)

S. Motonaga, H. Takebe, T. Wada, Y. Obana, J. Fujita, and Y. Ikegami: IPCR Cyclotron Progr. Rep., 14, 164

2)(1980).
H. Kumagai: Nucl. Instr. and Methods, §.., 213 (1960); S. Motonaga, Y. Miyazawa, N. Nakanishi, T. Tonuma,
M. Hemmi, and T. Karasawa: Reports I.P.C.R., (in Japanese), 40, 1 (1964); T. Karasawa, S. Motonaga, Y.
Miyazawa, and M. Hemmi: Proc. 1st Intern. Conf. on Magnet Technology, p. 239 (1965).

3)

Y. Ikegami, T. Wada, M. Hara, and S. Motonaga: Reports I.P.C.R., (in Japanese), 57, 177 (1981).

4)

A. Goto H. Takebe, S. Motonaga, T. Wada, Y. Yano, N. Nakanishi, and Y. Tanaka: ibid., p. 165.

166

N -19.

Structural Analysis of Sector Magnet by Finite Element Method

Y. Ikegami, T. Wada, and M. Hara

Finite element method (FEM) is widely used for the analysis of complex structures by the aid of digitalcomputer. i )resonator.

We are using this method for the structural analyses of sector magnet, vacuum chamber and RF

Here the results for the sector magnet are presented.
forces acting on it was analyzed.

The deformation of the sector magnet by various

The analysis has been done by using two-dimensional code (FEM-2)2) because

the data input is simple and fine element in FEM can be used, and the effects of slab structure of the yoke and asmall gap in the pole base are investigated.

The analysis by using three-dimensional code (SAP-5)3) is in progress.

The dimension and size of the sector magnet are shown elsewhere. 4 )the convenience of construction and transportation.
are used in the present analysis.
(1)

The yoke is divided into 16 slabs for

Table 1 lists the materials and their physical constants which

Three kinds of structures were investigated:

A structure in which the whole magnet is treated as a solid by considering that the pole, yokes and thespacers are strongly pulled to each other by magnetic forces.
(2)

A structure in which truss elements are inserted between the slabs by taking into account the slide

between the slabs.
(3) A structure in which two small gaps of 1 mm are introduced in the pole bases in order to decrease thedeformation of the pole.
Table 1.

Materials and their physical constants.

Part

Material

Specific gravity

Young's modulus(kg/mm2)

Poisson's ratio

Pole

Pure iron

7.87

21000

0.3

Yoke

Soft iron

7.70

21000

0.3

Spacer

SUS

8.03

21000

0.3

Figure 1 shows the subdivision of the sector magnet in the case of (1).

Specifying the thickness of eachelement, the three-dimensional effects are included. The magnetic force loaded on the pole face elements are
9.75 kg/cm 2 . The calculated deformations of the pole faces are shown in Fig. 2. Curve 1 is the result obtainedusing three spacers and curve 2 is that of only one spacer at innermost point of the pole face.
deformations of the whole magnet for the case (3) are shown in Fig. 3.
shapes before and after deformation, respectively.
three cases.

The calculated

The solid and broken lines show the

Figure 4 compares the deformation of pole faces for the above

As can be seen from the comparison between curve 1 and 2, the deformation of the case of slab

structure is about 4 times as large as that of the case of solid structure.

In the real case, however, the deformation

can be estimated to take the value between those two cases (about 0.1 mm).
(3), it seems that the effect of pole base gap is not large.

From the results for cases (2) andHowever, if the deformation of the pole base and poleface are compared, it can be seen that the deformation of the pole comes mainly from that of the part around thespacers.

Figure 5 shows the deformations of the bases of upper and lower poles.

It can be seen that deformations. decrease by about 40 % and 70 % for the upper and lower poles, respectively, if small gaps are introduced in thepole bases.

Figure 6 shows the stress distribution around the spacers.

smaller in the case of the structure with gaps.

The maximum stress becomes a little

The maximum compression stress (13.84 kg/mm2) is much smaller

167

than the allowed compression stress (52 kg/mm 2 ) and yield strength (21 kg/mm 2 ) of the stainless steel.
In the two-dimensional analysis, the deformation along azimuthal direction of this magnet cannot be
We are now using SAP-5 code for the three-dimensional analysis.

calculated.

Figure 7 shows the subdivision forcarrying out this calculation.

Radial distance from inner edge of sector magnet
500

1000

1500

2000

2500

Radial distanc e fr om inner edge of sector magnet
2500
0.01

o.

Fig. 1.

Lower pole

Vertical deflections of the pole faces.

Fig. 2 .

Subdivisions of theCurves (1) and (2)show the results using three and one spacer, respectively.

sector magnet for case (1).

Radial distance from inner edge of sec tor magnet
c

~).);

1M

1'».,

l:p:

(mm)

0

or>

.j..J

u

.,,
,,-

-- - ,.,-

(]J

.I :1

-

1

, ~+- = _-_~'-- -_i-'\ '\J,-:-i-) - j --j; -7; - /NP7/~, -1- - -,-~ ,-, -,~ ~ - ,-

~

.,

-;

1 :i

I

, -, 1)=1

,

,'

,

:

I

1

.1

:

1

:
I

01

'0

-- , --- - - I

(1)

(]J

4-

:~

.j..J

~

OJ

Upper pole

0
(rnm)

>

~
Radial distance from inner edge of sector magnet

i' fo--+--:.-+-11--+----------;1

I~

I"f----<f:-+--+--+--l

I

I

1N=4

'0
U

I

c

ICO

.s

1000

( 1)

IICO

1000

=

.j..J

u

~

01

4(]J

/ /

\1

'0

8

OJ

.j..J

L

0 .4

(]J

Imm)

>

sPoCER

SAlCER~

Iml

Fig. 3.

The deformation of the wholeFig 4.

magnet.

The solid and broken lines show

cases, (1), (2), and (3).

the shapes before and after deformation.
Deformation is exaggerated by a factor of

200.

Vertical deflection of the pole faces in the three

(mm)

168

Radial distance from Inner edge of sector magnetc:oRadial distance from inner edge of sector magnet

c:

o

+-'
U

Q)
~

Q)

"'CJ

Lower pole

'0
u

t

Q)

>

(rr.-n)Fig. 5.

Vertical deflection of the pole bases in the three cases,(1) , (2), and (3) .
( b)

(a)

1..02

3.86

3.92

3.4
3.29
3.1.3

3.4

1.72

Fig 6.

The distribution of stress (kg/mm2) around the central spacer:(a)no gap at the pole base.

(b)

1 mm gap at the pole base.

Fig. 7.

Subdivisions for three

dimensional analysis.

References
1)

O.C. Zienkiewicz: "The Finite Element Method in Engineering Science" , McGraw-Hill Publishing Co. Ltd.,England (1971).

2)

H. Togawa: "A Guide to Finite Element Method", Science Co. Ltd., Tokyo (1980).

3)

K.J. Bathe and E.L. Wilson : SAP IV-A Structural Analysis Program for Static and Dynamic Response ofLinear System, Report EERC 73-11, College of Engineering, University of California, Berkely , (June, 1973,
revised Apr. 1974).

4)

S. Motonaga, H. Takebe, T. Wada, A. Goto, J. Fujita, Y. Oikawa, I. Takeshita, and Y. Ikegami: 9th Intern.
Conf. on Cyclotrons and their Applications , Caen, France, Sept. (1981).

169

N -20.

Model Test of the Trim Coil for the SSC

H. Takebe, T. Wada, I. Takeshita,
S. Motonaga, J. Fujita, and Y. Tanaka

Trim coil of the sse sector magnet consists of 29 pair of coils. Each coil is made of a wide copper plate witha hollow conductor as seen in other report. l ) In the coils #1 to #7, electric currents are fed from hollow
conductors to the copper plates at the outer edge points, while currents are fed at the inner points in the coils#8 to #29. To investigate the magnetic field distribution around the edge of this trim coils and the field deviationfrom the isochronous field of the sector magnet, a straight shape model of the trim coil has been prepared and thefield is measured in 80 mm air gap of the H-type magnet. The results are compared with the calculations by
lOOOAPower Supplyt

Copper Plate(lOmmt)~yI

Measurin g
Area

IConductor(9 x 9 rom)

Fig. 1.

Plan view of the model

trim coil.
TRIM =

TRIM=

lOkG

IOOOR-OR
lOkG

( b)

(a)

6B

- SOOG

Fig. 2.

Magnetic field maps measured at trim coil current of

OA (a base field) (a), and 1000 A (b).

Fig. 3.

Effective field producedby the trim coil.

This is obtainedby substracting the base field (Fig.
2-a) from the field of Fig. 2-b.

170

TRIM code 2 ) using a current distribution on the copper plate which is calculated by a finite element method(FEM).3)
Figure 1 shows the model trim coil. Thickness of the copper plate is 10 mm and the hollow conductor(9 X 9 mm, hollow diameter = 6 mm) is welded by TIG method extending 30 mm on both the feed-in andfeed-out sides of the copper plate. At the centre of the copper plate a hole is bored, because in the case of the
SSC sector magnet there are hales for bolts to fix the trim coil on the pole face. One side of the copper plate
is made in the shape of 110° cut as in the case of trim coils #1 to #7 of SSC magnet. The other is of 90° cut tocompare the edge effect on the magnetic field. The magnetic field distribution has been measured by three Hall
generators whose driver was controled by LSI-II micro computer. The field was scanned by steps of 6 mm inboth X and V-directions in the area (138 mm X 368 mm) indicated by dashed line in Fig. 1. The X and
V-directions correspond to the radial and azimuthal direction in the SSC sector magnet.
Figure 2 (b) shows a measured map of the base field without the trim coil current and Fig. 2 (a) shows thatwith the current of 1000A. Difference of these two maps is the effective field of the trim coil. This is shown in
Fig. 3.
As an accelerated particle continues to sense the magnetic field along the beam path (Y-direction), integrated
value of the effective field is important around the edge region. These effective fields of 110° and 90° cut side of
the trim coil were integrated along the V-direction from the both edges to the centre line, respectively. Distributionsof these integrated values (S) are shown in Fig. 4.
Effective field boundaries (EFB's) of the field produc,ed by the trim coil were calculated by dividing thesedata (S) by the field values on the centre line indicated in Fig. 4. These EFB's on both sides are plotted inFig. 5. The variation of the boundary curve along the X-direction for 110° cut is larger than that for 90° cut. Thismeans that the outer lead type is not suitable for wide and short type trim coils. However, we adopted this type
for trim coils #1 to #7 of the SSC because of geometrical condition of return lead lines.

y

1
I-'
N
00

0

~

cO

0
U"\

0

.::r

C_e!!lLe...-lIlli'-- _y= 180.7rrm

E

E§'
if)
if)

0

::l

~

0

I'

t!)

:=
(/)

1

0
N

EFB (90°)

I-'

c:>
00

S

0

100

50

0

150

x

X (1Ml)Fig. 4.

Magnetic field distributions

Fig. 5.

Change of effective field
This is obtained byof effective field integrated along

boundary.

Y direction.

dividing the integrated field strength

S90 is integrated in

the range of Y = 00 mm - 180.7mm and S 110 in the range of Y =180.7 mm - 367.4 mm.

S by the value at the centre lines.

171

(a)

-~~

( b)

r-::;. .--

.c

k

----~

c
c
.c

l:?~

t:?-k
~~ ~

4J
•..-1

---- ----..-- ?
---~

/"
/'"

~

----- -- ---- ---.,-----------.,-- ----- --------- ------S:~~~~:::: " " "----:;::>---- /"---- /'"---.7------- 7-<:::

Ie::::::
Ie:::::: .c:::::

i-<::::: .c::::: .c'i-<::::: L.

§-----------===---...;
:;::>

----

~

i-<::::: .c:::::1.c::::: ---__

I-<::

t'-..

11 0' cut~b
• ..-1..Q~

7

k::::: ..----k::::: L
k:::::

..?"
/"
/'"

~
H

;7
~

"" "
::::::" '--.. "" " " " " """ "::::::"::-:--.. ". "- " " " "::::::" ::::::,.,"-,, '-" " " "~~~::::::,,::::::,.,'--.. "" "" "~"~:::::: " ""~"-~""""---~~.:::::".::::::" ~ "

~

''-

I

~

~

~

::::::,., ~ "-"------ ~ ~::::::"'~ ~----::::::",----- ~,,------~~,;:> - " ~ " ~ ~ "~r~~~~_T "'~:''::::-::-:::

L....

N

: : : ,., ',- ______" "·t~r-:~- J -. "~~:o,.._-:- ~X-direct ion ( x 0 , 41)

Fig. 6.

.::t

I

~

'" ',,, "'" ~ '--

~

5

0

~

X

aOeut

Fig. 7.

(a) Mesh plot used in the FEM calculation of current

distribution in the model trim coil.
factor of 2 .44.

-----!

l.['\

1'1\

~

~"

ill

X-direction is magnified by a10em

Calculated current density

distribution along the trim coil(b) Equipotential lines in the model trim coil.

centre.

To calculate the current distribution on this model of the trim coil , FEM was used to solve Laplace equation.
The mesh plot for this calculation is shown in Fig. 6 (a), and the resultant equipotential lines on the copper plateis shown in Fig. 6 (b). Figure 7 shows the current density distribution along the centre line of the trim coil.
From this current distribution, the distribution of the magnetic field was calculated using a computer code TRIM.
Figure 8 shows the distribution of the measured magnetic field along the X-directions as well as the calculated ones.

It can be seen that the calculated field distribution on the centre line agrees well with the measured one . From thisresult we considered that the TRIM code is feasible in the design of the trim coil for the SSC. We estimated the fielddeviation from the isochronous field caused by the finite width of the trim coils in detail.
The H-type magnet used to generate the base field in this test has a pole piece different slightly in shapefrom that of the SSC sector magnet. Therefore, the effective field boundary measured in this test will be slightly
different from that of the SSC sector magnet. In the design of the trim coil of the SSC, the data obtained in thistest have to be modified to adopt to the real dimension of the SSC trim coils. Using this modified field andintroducing the edge effect, the phase slip of an accelerated beam will be calculated.

'"
C)

o

W " ' i vo Fi old on <ho

o
<:>

/1"

Fig. 8.
oo'i>/ /

Trim Co il Centre

I~.

distributions of effective field in
X-direction.

~Integrated Va lu e

0 : Calculation by TRIM

code using the current density distribution
in Fig. 7.

,lon g Y- dim"o,.6 :Measured value.

e: Calculation by TRIM code using a

constant current distribution.

~/

A:

Integrated effective field of 110° cut

along the Y -direction (this is normalizedIoMeasured and calculated

X (em)
C!'OSTtion of Tr im Coil

I
10

15

10 1

at both edge of the measured points in
X-direction).

172

References
1)

H. Takebe, A. Goto, S. Motonaga, T. Wada, Y. Oikawa, and I. Takeshita: p.173 in this report.

2)

J.S. Colonais and J.H. Porst: Magnet Design Applications of the Magnetostatic Problem, called TRIM ,UCRL-16382 (1965).
O.C. Zienkiewicz: The Finite Element Method in Engineering Science, McGrow-Hill Publishing Co. Ltd.
(1971 ).

3)

173

N -21.

Design of the Trim Coils for the RIKEN SSC

H. Takebe, A. Goto , S. Motonaga,
T. Wada, Y. Oikawa, and I. Takeshita

A final design of the trim coils for the SSC sector magnets was achieved on the basis of model measurements l ), 2)
and calculations.
The number of the trim coils and their radial positions were so determined that the deviation of the trim
coils' field from the isochronous field should be less than 0.05 %. To perform the above requirement a computercode which can optimise the currents of the coils with a least squares method has been developed. 3 ) Optimum
currents can be obtained to minimize the following quantity:.'\.

Q= ~ WIi =I

nc0( ~a ·· x · + Bi j = I IJ
J

2

Bi )

,

(1)

whe re B~\ and B.\ are the base field and the ideal isochronous field , respe ctively , at radial distance R..\ Here x.J isthe current of the j-th trim coil , a..
x. the field which is produced at R.\ by the coil , and n c the number of trim\] ]coils. N is the number of radial positions where the field data were taken and w.1 the weighting factor. Here w.'1 s
are so adjusted that the deviations of squares in Eqn . (I) become almost the same over the whole
region of R..\
Furthermore. in this calculation the optimum value of the base field B.\o that minimizes the following quantity is
automatically searched :I1c

P = J~ K J x · 2(2)Here K. is the weighting factor which prevents the particular current to become large. It was found that usingJthis procedure the agreement between the field corrected by trim coils and the ideal isochronous field is fairly well
improved . In this calculation it is possible to divide all the coils into any desired groups and to calculate theiroptimum currents under such a constraint th at the coils belonging to each group have the same current. For basefield and trim coil fields we used the values which were calculated with the TRIM code. 4 ) It is noted here thatthe field step hejght of the trim coils varies with the strength of the base field. We thus modified the radial
field distribution by the trim coil in such a way that the above effect can be taken into account. The field atradius R.\ which is produced by the j-th trim coil is calculated by regarding the isochronous field at radius R.1 as thebase field. The field profiles thus obtained are presented in Fig. 1.
Because the radial increase of isochronous field is the largest for the 134 MeV/u 12Ci+ ion in the RIKEN SSC ,we have designed the configuration of the trim coils in such a way that we can realize the isochronous fieldefficiently for this case. In this procedure , the following conditions were taken into account: (1) the current of
SO l

en
U)

::J
<t:

8

::1
20 f
10 1
I

or-- 10

-20 ~

:l
-50

Fig. 1. Calculated magnetic field distribution
formed by trim coils at the base field of 15.5 kG
when each coil current is 100A.

174

Table 1.

Radial positions and widths on sector centre lines andoptimized currents of the trim coils for 184 MeV P, 71 MeV/uC6+, 134 MeV/u C6+, and 13.6 MeV/u 238U40+. Each trim
coil is connected to each power supply of the indicated type.
P( 184 MeV)

Type of(71 MeV/ u)(134 MeV/ u) (13.6 MeV / u)

power supply

R(cm)

H (cm)

I (A)

1 (A)

1 (A)

1 (A)

78.0

5.0

- 149.61- 178.09

34.74- 76.04

2

83.5

5.0

37 .6566.37- 105.86- 30.74

E

3

89.0

5.5

- 8.15- 20.1238.31- 6.71

E

No.

-c

4

95.0

6.0

38.55

32.97

44.24

- 19.82E

510 l.5

11. 5

72.20

69.05

129.28

30.42

C

6

11 3.5

11.5

93.85

60 .1 921 1.68

19.62

C

7

125 .511 .5109. 17115.43200.03128 .02

C

8

137.5

16.5

226 .96140.4 7340.78

41.03

B

9

154 .5

16 .8

209.72139.11

3 18.65

93.88

B

10

171.8

20.0

303.96

182.79484.74

97.89

II

192.3

18.5

303.96

182.79484.7497.89

12

2 11. 316.6

313.46189.4 7494.24

95.37

13

228.4

15.3

313.46189.4 7494.2495 .3714244 .214.5

324.80182.99503.0776.22

15259 .213.5

324 .80

182.99503.0776.22

16273 .2

12.3

321.19164.36495.4876 .57

Serial in

17

286.0

11.3

321. 19164.36495.487657

4-sectors

18

297.8

10.4

321.62158.5048 1.89

68.84

trim coi ls

19

308.7

9.8

321.62158 .50481.8968 .8420

3 19.09.3

322.60150.86481.74

66.04

21

328.8

8.6

322.60150.8648 1.74

66.04

22

337.9

8.3

323.62146.45482.31

68.78

A

23

346.7

78

328 .01

146.46479.54

69.82

B

24

356.0

7.4

330.05143.66480.16

66.01

B

25

362.9

69

337. 19147.6 7480.9877 .20

B

26

370.0

1.2

40.03

- 1.02

54 .3 9- 38.48

27

371.4

1. 2

66.58

58 .0696.70

69 .26

28

372.8

5.8

287.3092.95

414.92

0.70

o

29

379.1

4.2

275. 19136.97341.5583.30

B

Harmonic~ } Harmonic

coils should change gradually with their radial position and (2) the maximum current should not exceed 500 A.
Coils of 29 sets including 5 sets of harmonic coils 5 ) were found to be necessary.

The radial positions and widthsof the coils thus determined are tabulated in Table 1 together with the optimized currents for some typical ions.
Some pairs of adjacent coils are connected in series.

The currents required for isochronization on the 134 Me V /u

12C6+ and 13.6 MeV/u 238U40+ ions, respectively, give maximum and minimum values in our case.
trim coils is shown in Fig. 2.

A plan of theThree coils from No.5 to No.7 are used as harmonic coils for the beam centeringand the two, No. 26 and No. 27, for the beam off-centering.

Return leads of the coils No.1 - 7 are woundaround the nose of the pole and the others around its back.

The coils are made of copper plates and are woundalong equilibrium orbits in a hard-edge field distribution.

The theoretical magnetic field produced by the coilconfiguration thus obtained agrees with the ideal isochronous field within difference of less than 0.05 % as shownin Fig. 3.
The connections of the leads were designed and the specifications of power supplies for the trim coils were
determined using Table 1.

We have decided to use five types of power supplies (types A - E) according to widthsof the setting current of each trim coil.

The voltages and currents of each type of power supply are listed in175

17 . 0

I KGI

I

-"L

MochinTCent reSector. I SO- - - BASE
CAL

16 . 0Centre li ne

I....<Cl- - - -- -- ------ -- -Z

~ 15 · 0
(j)

S
W

;:;::

14 . 013 . 0200

100

Fig. 2.

Plan of the trim coils for the sector magnet.

Fig. 3 .

R ( eM)

40 0

300

Comparison of the magnetic field distribution

formed by the trim coils with the isochronous field
for acceleration of C6 + to 134 Me V lu.

Table 2.

Specifications of five types fo power supplies for the trim coilsof the four sector magnets. The number of total parameters to be set
by computer is 71. Total power of the trim coils is estimated to be 192 kW.
Max.

Power

B y l'~' s

NumberNumbe rTota lCurr. (A)

Volt.

(kW)

Curr o (A)o f blan chs

o f P.S.

powe r (kW)50 ~ 500
30 ~ 500

205

10 3

30

7

I

103

51

25.5

100

12

2

51

315
500

2 .6
4
0.9

16
12
12

13 .1
24

70

0.82
2.0
0.1

Max.

Min .
Type

A

B

Bypass} control
system

C
0
E

- 75
- 500

with
polarity
switch

- 100

~

~
~

.. _-

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

Table 2.

192

Paramete rs: 7 1

Total

1. 2

. ....... .. ... -The power supply of type A is used for the coils from No. 10 to No. 22 .

Coils No . 10 and No. 11,

No 12, and No . 13, No. 14 and No. 15 , No. 16 , and No. 17 , No. 18 and No. 19, No . 20, and No. 21 are eachconnected in series. Each of the above pairs and coil No. 22 are also connected in series through four sectors'
trim coils, because the disturbance in the region from NO . 8 to No. 22 coils due to the injection or extraction
elements or the harmonic coils will be small enough.
adjacent pairs of these coils are less than 30 A.
control circuits as shown in Fig. 4.

Furthermore, the differences of the currents between the

Therefore the currents of all these pairs are adjusted by a bypass

The number and the length of thick cables can be decreased in this method ,resulting in an appreciable saving in power losses.

This type of power supply has a transisterized regulator and asaturatable reactor.
One power supply of type B is used for coils No.8, No.9 , and No. 29, and the other of type B for coilsfrom No. 23 to No. 25.

These coils are connected through bypass circuits in the same manner as in the case oftype A power supply but are not in series through the four sectors' trim coils.
The other coils are excited by power supplies of types C, D and E with a polarity switch.

They areconnected to each power supply independently, because their currents differ by a large amount.
The currents are controlled by a computer with a 12 bits DI A converter using CAMAC system.

The detailed

specification of above power supplies will be written according to the results of field measurement for the real
sector magnets and the trim coils.

176

TRIM COIL #I ~ ~ 4l-'
Iii ~I

10

10 11

10 11

11

JE"SATURA---T~ABLE-<'-=----'---t-1----<I>-----oIlt'O

REACTORAC 44 0v

INPUT

CAMAC

f r om,COMPUTOR

POWER SUPPLYS VAULT

Fig. 4.

SECTOR SI

SECTOR~SECTOR NI SECTOR E

I--~~ ~ CYCLOTRON VAULT

Example of the schematic diagram of the trim coil power supply (type A) andelectrical connection of the trim coil #10 to #22.

The trim coils will be made of 6 mm thick copper plates to which a 6 mm (t) X 12 mm (w) copper hollow
conductor is welded partially by a TIG method , except fo r the coils No . 26 and No. 27 which consist of only
hollow conductors. These hollow conductors are also used as return leads.
We decided to weld the hollow conductor to the inner side of the copper plate for the coils from No. 8 toNo. 25 , and No. 28 and No. 29 , as a result of the model test measurement of a current distribution in the plate .2 )For the coils from No.1 to No.7 , however, the hollow conductor is welded to the outer side of the plate becauseof the geometrical condition of the return lead. Each coil will be fixed to the pole face with specially madebolts.6) The surface of the trim coil will be coated with aluminum oxide for insulation. The return lead will be
taped with a Kapton sheet.

The outgassing from these insulators does not pose serious problem because they are

not installed in a high vacuum chamber but in a low (sub-) vacuum one .6 )The trim coils are now under preparation by Sumitomo Heavy Industry Co. , Ltd . and wjll be mounted on the
sector magnets for the field measurement which will begin in the spring of 1982 .

References
1)

H. Takebe , S. Motonaga , T. Wada, J . Fujita, and K. Ogiwara : IPCR Cyclotron Progr. Rep. , ll.., 4 (1979).

2)

H. Takebe, T:Wada, I. Takeshita, S. Motonaga, J. Fujita, and Y. Tanaka: p. 169 in this report.

3)

A. Goto , H. Takebe, S. Motonaga, T. Wada, Y. Yano , N. Nakanishi, and Y. Tanaka: Reports I.P.C.R. ,(in Japanese), 56 , 165 (1981) .

4)

J.S. Colonais and J.H . Porst: Magnet Design Applications of the Magnetostatics , call TRIM, UCRL-16382

5)
6)(1965) .
A. Goto , Y. Yano, and N .. Nakanishi: p. 159 in this repo rt.
S. Motonaga, H. Takebe , A. Goto , J . Fujita , T. Wada, Y. Oikawa , 1. Takeshita , and Y. Ikegami: p.162
in this report.

177

N -22.

Automatic Measuring System of Magnetic Field Distribution

J . Fujita , T. Wada, and H. Takebe

The LSI-II microcomputer system mentioned before l ) is further expanded in its peripheral
equipments and nearly full-automatic measurement of the magnetic field distribution is becoming
possible. The latest system structure is shown in Fig. 1.

GP - IB BUS
30 ch.
Inputs L - -_ _--.J

L....L----L.....!.-DSD - 440

MT - 1000

Mag net Curre nt
Con t ro ller

(J)
~

TTY

co
I

R - dir.

L A- 36 Co lour

CRTaIF - 800>---C. P~ - :~~«g - dir.

I

I
I
I
I
I
I

o

u

«
L
«
u

Fig. 1.

u5" mi ni FDf------cJ-1 C=81

Acoustic Couple r

Block diagram of automatic system for measurementof magnetic field distribution.
A Hall assembly, on which 20 elements are set in line to radial direction at an interval of 20mm, measures the two dimensional field distribution by scanning both radial and azimuthal
directions. It moves with mechanical stroke of a set of air cylinders actuated by theelectromagnetic valves which are controlled by a CAMAC register. The output of the register isgiven via home made optical coupler to isolate noise. Position information of both directions isread into a 24 bits input register via rotary encoders.
A helical potentiometer which set an exciting current of magnet coils at each magnetic flux
density is replaced by a digital-to-analogue converter (DAC) . An output voltage of the DAC which
is held in a thermally controlled oven has a temperature stability better than 10- 4
and istc

178

controlled by two serial pulses of Up/Down and Clock from the above mentioned CAMAC output
register.
Very small analogue voltages derived from 20 Hall elements, Pt-wire thermal sensors in theHall assembly and a DC -CT transducer of the magnet coil current are multiplexed by a relay
scanner FLUKE 2204A with 30 input channels and switching speed less than 14 msec, andmeasured by a digital voltmeter FLUKE 8502A.
on a common GP-IB bus.

The scanner and voltmeter are serially connected

A magnetic tape unit TEAC MT -1000 with a tape speed of 45 IPS and a record density of1600 BPI is added to the LSI-II bus in order to increase data storage capacity necessiated byprogress of the automatic measuring system. A cassette tape unit with 15 IPS tape speed and 800
BPI record density can also be used.
An OKI IF-800 intelligent terminal is used for processing simple graphic demands and also
serves as a tool for development of application programs. It can work also as a second terminal in
the RT-ll multi-terminal monitor. The components of the IF-800 are 64 KB MOS RAM, dual 5
inch mini-floppy disks, a video display with graphic resolution of 200 X 640 dots, eight colour
description and a light pen, and a keyboard printer.

The IF -800 is connected to the LSI-II by

RS-232C serial lines. Signal transfer rate is selectable with a switch at 300 or 9600 Baud. The
serial port in the IF-800 can be connected to a telephone via an acoustic coupler and make anexchange of data and programs with remote stations. The IF-800 is provided with BASIC and
CP/M as operating system, and also utilities such as a screen editor and C-compiler which aredeveloped by Dr. T. Soma of the Information Science Laboratory of our Institute to fit with the
IF-800. The screen editor makes coding and change of source programs easy and speedy.
We are developing whole programs for various arrangements of measurement. The mainpart of the programs is written in FORTRAN and the remainders, especially for CAMAC modules,
are written in Macro-assembly language as the subroutines of the FORTRAN programs.

Those

programs are expected to relieve one from the tedious work of measurements such as the watch of
the instruments for hours.

ReferenceI)

J. Fujita, T. Wada, and H. Takebe: IPCR Cyclotron Progr. Rep., !±, 179 (1980).

179

N -23.

Beam Transport System for the RIKEN

sse (II)

Injecting Transfer LineN. Kishida and Y. Yano

Construction of the separated sector cyclotron (SSC) is now in progress at RIKEN.

As aresult of the recent design work of the main building the position where the SSC is to be installed1
was altered from that given in a previous report. ) Therefore the beam transport system between
the SSC and pre accelerators (the heavy-ion linac already completed and the A VF cyclotron) has
been reconsidered.
Layout of the accelerators is shown in Fig. 1.

Fig. 1.

Their beam lines are not on the same horizontal

The plan view of the beam transport system for

the IPCR SSC. The beam levels of the SSC, the linac and
the AVF cyclotron are not on the same horizontal plane.
The median plane of the SSC is 12.5 m below the beamlevel of the linac and is 4 m below the median plane of
the AVF cyclotron.

180

plane. The median plane of the SSC is to be 12.5 m below the beam level of the linac and 4.0 m
below the median plane of the AVF cyclotron.
The perspective view of the redesigned beam transport system is shown in Fig. 2.

ChargeSLO

o : Dipole Magnet
QS : Quad~upoJe Singlet
QD : Quadrupole Doublet
QT : Quadrupole Triplet
QTC1

SCO
QOC1
DC1
QDC2
SC1

>
SL7

Fig. 2.

Perspective view of the beam transport system between the linac and the SSC,

and between the AVF cyclotron and the SSC. The vertical distance between SLO andSL3 is 8.5 m and that between SL6 and SL 7 is 4.0 m.

Table 1 (a).

The beam matrices of the first- and second-order calculations
for the system I at the beam injection point (TRANSPORT
printout).

First-order
0.285 CM
2.154 MR
0.267 CM
2.251 MR
3.004 CM0.075 PC

- 0.002-0.000-0.0000.194
0.214

Second-order
0.057
0.296 CM
0.111
2.177 MR
0.006
0.267 CM
0.041
2.644 MR
- 0.271
3.017 CM
0.0
0.075 PC

0.012
0.001
0.002
0.161
0.205

0.0
0.0
0.0
0.0
0.0
0.0

-0.000- 0.000
0.058
0.000

-0.0000.000-0.000-0.000- 0.000

0.909

0.000
0.022
0.058
0.004

0.014
- 0.001-0.000

0.000
0.001

0.905

181

Table 1 (b). The beam matrices of the first- and second-order calculations
for the system II at the beam injection point (TRANSPORT
printout).
First-order
0.285 eM
0.0
2.154 MR
0.0

-0.002

0.0
0.0
0.0

0.267 CM
2.251 MR3.995 CM

-0.000-0.000
0.156

0.000
0.000
-0.0780.000- 0.000-0.0000.0

0.075 PC

0.214

-0.000- 0.000-0.0000.755

Second ~rder
0.080
0.301 CM-0.5262.238 MR
0.274 CM
0.001
0.000
2.756 MR
- 0.520
4.013 CM0.075 PC
0.0

-0.0550.001-0.002-0.002-0.002

0.141
0.222

- 0.045
0.004

0.041
-0.0000.000-0.000-0.0000.752

stripping and charge selection parts are installed between SLO and SL3 and between SCO and SC 1
to decrease the magnetic rigidity of preaccelerated ions and to increase the attainable maximum
energy of the SSC. The transverse phase-space matching is performed in the section between SL5
and SL6 , where the beam is achromatic. The dispersive beam from the AVF cyclotron is
achromatized through the section between SC 1 and SC2. In the following explanation we referto the beam transport system from the linac (the AVF cyclotron) to the SSC as system I (system
II).
The calculation of ion-optics in this system has been made to the second-order with the aidof the computer program TRANSPORT. 2 ) Table 1 presents the beam parameters (TRANSPORT
outputs) at the beam injection point to the extent of the first- and second-order calculations forthe system I and II. The ratios of the phase-space area of the first-order calculations to that of
the second-order ones are tabulated in Table 2.

Table 2.

The ratios of the phase-space area of thefirst-order calculations to that of the secondorder ones for the system I and II at the beam
injection point.
On midplane

Off midplane

System I

1.05

1.17

System II

1.10

1.26

182

It is found that the first moments of the beams (centroid shift) are negligibly small.
Furthermore the extents of the enlargements of the phase-space ellipses will give no troubles forthe beam acceleration in the SSC.
The full discussion of this work has been published in Ref. 3.

References
1)

N. Kishida, Y. Yano, and T. Wada: Sci. Papers I.P.C.R., 74, 105 (1980).

2)

K.L. Brown, F. Rothacker, D.C. Carey, and C. Iselin: SLAC Report, No. 91, Rev. 1(1974).

3)

N. Kishida and Y. Yano: Sci. Papers I.P.C.R.,]!i, 214 (1981).

183

N -24.

Beam Extraction System for the RIKEN

sse (I)

N. Kishida, A. Goto, and Y. Yano

This report presents the layout of beam extraction system proposed on the basis of thecalculated results for extraction trajectory orbit.
In designing the system, the following points were taken into account: (1) To realize singleturn extraction; (2) To extract the beam before crossing vr = 1 resonance; (3) To use the extraction
elements which can be manufactured without mechanical difficulty.
Heavy-ions and low-energy light-ions can be extracted by only RF acceleration. In the caseof high energy light-ions, however, the separation of the beam on the extraction orbit from thebeam on the last acceleration orbit is not suffici ently large for single-turn extraction. Therefore weuse the first harmonic field perturbation to enlarge the beam separation in the extraction region
and to realize the single-turn extraction for these ions. In this process we extract the beam
before vr = 1 resonance to avoid the strong radial defocusing of the extracted beam caused by thefringe field of the sector magnet. As for the detailed study on this procedure, see Ref. 1. The
following two procedures were taken in determining arrangement of the extraction elements.
Firstly , the extraction trajectory was calculated under the hard edge approximation of the magnetic
field and no RF acceleration in such a way that the number of the elements and the power
comsumption in each element could be minimized and that the beam separation enlarged.
Secondly the extraction trajectory and the element arrangement were determined precisely using thenumerical orbit calculation program EXTRACT,2) where the realistic magnetic field was used andthe first harmonic field perturbation was included. The beam which was traced numerically fromthe beam injection point was used as the beam entering into the extraction region in thiscalculation.
The extraction trajectory was investigated for 135 Me Vlu 12C6+ ion, since this has the highest
magnetic and electric rigidity and the smallest beam separation and is , therefore , the most difficult
to extract. The proposed extraction system consists of one electrostatic deflection channel (EDC) ,two magnetic deflection channels (MDC 1 and MDC2) and two extraction bending magnets (EBM 1
and EBM2). The layout of the extraction elements and their characteristics are shown in Fig. 1
and Table I , respectively.
The beam width were estimated by tracing trajectories of five particles on six-dimensional
phase-spaces using EXTRACT. Figure 2 shows the orbit separation between the extraction
traj ectory and the last acceleration traj ectory . We then calculated the beam separation which isdefined as the orbit separation minus the beam extents. The calculated separation gives sufficientspace so that the extraction elements are expected to be safe from the heavy bombardment by
the beam.
The maximum E.V. value of EDC was selected in such a way that spark-over will not occur.
MDC's are composed of current septums and coils to self-compensate the field overshoot to theoutside. EBMI is the same type of magnet as BMI used in a beam injection system. 3 ) A

184

window-frame type magnet without the outer return yoke is adopted as EBM2.
and mechanical design of each element is now in progress.

I~I

u

10

CJ

w

I

Z
<::)

.......

0:::

~I

! i
i i
ii ii
!. i:

~

L
U

tCI

Field optimization

I

1

i

5

CI

a....
w

(f)

t-

.......
co
0:::
<::)

i
(DEGREE)-30
OPEN
VALLEY

Layout of the proposed
Fig. 1.
extraction system together withthe extraction orbit and the lastacceleration orbit for 134 Me Vlu
12e6+ ion.

VALLEY

HILL

IRFJ

HILL

OPEN
VALLEYI

Fig. 2.
Orbit separation between the extraction
and the last acceleration orbits as a function of
azimuthal position in the sse.

Characteristics of extraction elements.

Table 1.

Aperture (cm)Element

Bend angle (deg)

EDC

0.79

2

MDCl

18

3

MDC2

25

EBMI
EBM2

~

(H)

(V)

Radius (cm) Maximum field

F ace angle (deg)(entrance )/( exit)

linear

40 kV/cm

4213- 0.5 kG

o

3

4

230

- 1.7 kG

o

o
o

10

4

4.2

344

10

kG

o

o

35

4

4

191

18

kG

o

o

References
1)
2)
3)

A. Goto, Y. Yano, and N. Nakanishi: Sci. Papers I.p.e.R., 75, 204 (1981).
A. Goto: Reports I.p.e.R., (in Japanese), 57, 203 (1981).
Y. Yano, H. Takebe, S. Motonaga, T. Wada, J. Fujita, and A. Goto: Sci. Papers I.p.e.R., 75,
176 (1981).

185

N -25.

Model Study of Magnetic Inflection Channel for the SSC

H. Takebe, Y. Yano, S. Motonaga, T. Wada,J. Fujita, Y. Ikegami, and M. Hosoyama

A couple of magnetic inflection channels (MIC 1 and MIC2) , which are used as the beam injection elements
for the SSC , are inserted into a 50 mm available gap between the sector magnet poles. 1 ) They have to give field
increases in ratios (Ao) of 8 % (MIC 1) and 23 % (MIC2), respectively , to the sector field.

They have not to givea large disturbance to the sector field.
A basic design of the MIC was made by using a computer code Trim.2)

We constructed a straight-shaped

I/l-scale model and tested it in the gap of an H-type magnet, which was a 1/3-scale model of the present 160 cm
ordinary type cyclotron.

The gap length was modified to 80 mm from 87 mm by placing a 7 mm thick iron plateon the lower pole.
A photograph of a top view of the model MIC is shown in Fig. 1, and a cross sectional view in Fig. 2.

Theiron shims are replaceable and their thickness can be selected to be 1 mm , 3 mm , and 5 mm. Four turns of thecoils are divided into two pairs, each of which has two turns.

The inner two turns compose coil A and the outerones coil B. The compensation coil of four turns are wound on the left side of the MIC.
are contained in a brass coil holder.

The coils and iron shims

The coils are made of a 9 mm X 9 mm copper hollow conductor which has a water path of 6 mm indiameter.

At the maximum current of 3 kA , the flow rate of cooling water amounts up to about 10 e/min to

keep the coil temperature at a moderate value.

The conductors are insulated by Kapton film .

The magnetic field was measured by Hall generators of BHT -910 series (F.W. Bell Inc.).
generators were placed at intervals of 6 mm on a Hall assembly, as is shown in Fig. 3.

Three Hall

As the temperature of theIron shim
Compensation coil,----A-----,

MIC coil/ Copper hollow conductor~ /,9x9-6¢

rT""''''~~~~~--r'C...".....,......,......,.~...".....,."""","*~

Insula torr--..:...:::......-+--_~_ _--t--------'3"-".5_'- ---l Brass coil hal der-9Fig. 1.

A top view of the model MIC,

Fig. 2.

I
9 rrrnI
41)
X-dir ec ti on

Cross section of the Ill-scale model MIC; dimensions

which has a straight shape of 230 mm inin mm. Middle two turns of the MIC coils compose coil A,

length.

and top and bottom ones coil B.

The MIC coils are wound on theright side.

186

ALUMINU~' CHN NEL\ (l5x15x800Mr-,)

Fig. 3.

Hall assembly mounted on a 15 mm X 15 mmaluminum channel. Three Hall generators (BHT -910)
are placed at intervals of 6 mm with thermister heaters
T H E R~' I STE R

and aPt-thermometer.

PT - THERr10METERHEATERS

HALL ASSEMBLY

,:
I

-

-

- - -I

1~~O~TEJ1--'-1

-

--

I

I

TEMPERATURECALIBRATION

x -Y

Fig. 4.

Block diagram of the field measuring system. Measuring procedure except for setting a coilcurrent is automatically controlled by the computer LSI-II.
Hall generators was not kept constant, we corrected the measured Hall output taking account of its temperaturedependence , to obtain an accurate magnetic field strength. 3 )Error of the measurement was within ±1 .S X 10-4

in relative value and ±3 X 10 -4 in absolute value.
Figure 4 shows a block diagram of the measuring system.

All the measuring procedure except for setting

the coil current was done automatically by the computer (LSI-II).
Figure S shows some examples of measured field distributions inside the MIC at different currents.

In orderto obtain multipole components of these field distributions , the data were fitted to the following biquadrupolepolynominal:

by using a least-squares method, where X indicates a transverse position from the MIC centre, in cm unit.
Figures 6 and 7 show examples of the field increase ratio, A o ' and sextupole compon.ent € which is given byc. = Ao A 2/ ( Ao + 1 ) .
Data were obtained at the base field of 16 kG for the iron shim thickness of 5 mm (a) , 3 mm (b) , and I mm (c).

187

Results obtained when the coil A was used are shown in Fig. 6, and those with the coils A and B connected inseries in Fig. 7. This latter arrangement will be called coil A & B.. As shown in Fig. 6 (b) , the sextupole
component becomes zero at the current of 850 A, and Ao is given as 9.3 %.
The sextupole component of the value within ± 1 X 10- 3 was supposed to be permissible for the ion-opticalproperty of the beam.4)

Table 1 shows the field increase ratios (Ao) and the currents when the sextupole

component is + 1 X 10- 3 and -1 X 10 -3.

An available field increase ratio for each base field is shown in Fig. 8.

The thick solid line indicates the maximum coil current for uniform MIC field.

From this figure, we can conclude

as follows:

900A __ ______.
700A/
50DA

-----

c

o

0::)
I
0::)

DA

~I

o

-0.9

Fig. 5.

0.9

X-DIRECTION ( an )

10

5
N

«

0

/ '

0

/

.

....

I

0

«

0

0

0

£

1 0

/

0

",

/

w

/

(c )
Ao

N

«

o

3

0

,"

w

1

I

... ..... -'0___ _ _-1.

£

....

,

0
.-<

0

J

£

+H+<I-+--+--+---+---+--+ - 5+t+H1-+-+---+--+---+--+ - 5

012

10
(b)

...,

....

/

,/

/

Typical example of transverse field distributions inside the

MIC at different current of the coil A. The iron shim of 3 mm inthickness was used. The base field was set to be 16 kG.

W

-5

o

3

2

3

CURRENT OF COIL A ( kA )Fig. 6.

Change of field increase ratio (Ao) and sextupole component (e) withcurrent of the coil A.

Data was obtained at the base field of 16 kG for the ironshims of three different thickness: 5 mm (a), 3 mm (b), and 1 mm (c).

/

(a)

,/

20

10

' /~o

/

/

20

/

V

(b)

/

1 /

....

N

I ~~

N

0
0

«

0

0

0

.0

0

,--------Ew£,---'-'~

."---

0

(c )

1

I

<

'-'1i--

3

/

10
N

<

0

0

/

/

5
....
I

0

c/ ,

,/

0

"r'

w

w

-5

-5

-5
2

20
Ao/

/

10

Ao

0

1

2

3

0

1

2

3

CURRENT OF COI L A&B ( kA )Fig. 7.

Change of field increase ratio (Ao) and sextupole component (e) withcurrent of the coil A & B.

Data was obtained at the base field of 16 kG.

188

Fig. 8.

Field increase ratio (Ao) corresponding to the case ofo6
THICKNESS OF IRON SH IM (MM)

Table 1.

3

at different base-field strengths (Bb ase ) . Data wereobtained for coil A (a) and coil A & B (b). The shaded region
indicates the values of Ao which can be changed independentlyof the base field under the condition of -1 X 10- 3 < E < 1 X 10 -3 .

E = ± 1 X 10-

Field increase ratios corresponding to the case of E = +10 - 3 and -10- 3 .

Coil A

~
(kG)

Iron
shim
E

(

t

6.209

Imm

3mm

5mm
+ 1 X 10- 3- 1 X 10- 3+1 X 10- 3

18.5%

16.2

10.4

660A

390A

- 1 X 10- 3+1 X 10- 3- 1 X 10- 3
1.8

8.4

3.8

380A

150A

230A

OA

5.0

1.8

]0.022

~

19.1

16.7

10.7

8.6

\.

1200A

770A

670A

270A

580A

OA

{

19.0

16.6

10.7

8.5

4.8

2.3

12.924

1600A

]OOOA

880A

330A

680A

90A

16.017

{

18.4

16.3

10.2

8.4

5.0

2.7

2150A

1450A

1150A

550A

950A

300A

Coil A & B

~
(kG)

Iron
shim

3mm
+ 1 X ] 0- 3

E

Imm

0.0

- 1 X 10- 3+1 X 10- 3- 1 X 10- 3

6.209

{

38 .0%

19 .4

31.7

6.8

2000A

760A

2000A

330A

{

(38.2)

25.2

23.0

13.4

10.022

3400A

1940A

2300A

1220A

12.924~\.

(38.7)

30.8

22.5

19.0

12.4

3900A

2800A

1660A

2400A

1450A

(

(37)

(28.5)

20.0

14.5

9.3

5500A

3700A

2400A

2350A

1320A

16.017t

189

The MICI should be composed of 2.6 mm thick iron shim and the coil A in order to get the field increase
ratio of 8 %. The optimum current at base field of 16 kG is estimated to be 800 A.
On the other hand , MIC2 needs the field increase ratio of 23 %.
iron shim and the coil A.

Then it is necessary to use a 6 mm thick

The maximum current is estimated to be about 2800 A.

However it is also possible

to use a 2.2 mm thick iron shim and the coil A & B. The maximum current is estimated to be of a similar value.
The ampere-turns for the latter is twice as large as those for the former.
A disturbance outside the MIC and an effective field boundary change of the MIC are discribed elsewhere. S )References
1)

A. Goto , Y. Yano , T. Wada, and N. Nakanishi: Sci. Papers I.P.C.R. , 74, 124 (1980).

2)

J.S. Colonais and J .H. Porst: Magnet Design Applications of the Magnetostatic Problem , called TRIM

3)

UCRL-1638 2 (1965).
H. Takebe, Y. Yano, T. Wada , J. Fujita , Y. Obana, and S. Motonaga: IPCR Cyclotron Progr. Rep. , 14, 176

4)5)(1980) .
Y. Yano: Sci. Papers I.P.C.R., 74, 13 (1980).
H. Takebe , Y . Yano , S. Motonaga, T . Wada , J. Fujita, and Y . Ikegami: ibid. , 75, 193 (1981).

190

N -26.

Calculation of RF Electromagnetic Field

by Finite Element Method

M. Hara, T. Wada, and F. Kikuchi

In designing the RF resonators for accelerators, it is usual to evaluate RF characteristics on the basis oftransmission line approximation or to depend on the experiments with scale models.

Because the transmission line

approximation is essentially one dimensional one, it is not useful to estimate the field distribution along theaccelerating gap and to estimate the microscopic current density.
requires large expense to build models.

In the model studies, it takes long time andIn order to get a detailed analysis, we are now developing a computer code to calculate the electromagnetic
field in an arbitrary three dimensional cavity resonator.

As a first step we have developed two computer codes toevaluate the resonance frequency, electromagnetic field and other pertinent quantities by solving directly theMaxwell equations using finite element method.1)

One is for the field in a straight resonator with arbitrary crosssection (H2DB) and the other for the axisymmetric field (HAX).

In the former, scalar Helmholtz equation

is solved with Dirichlet and/or Neumann boundary conditions.

In the latter, axisymmetric Helmholtz equation

a 1 a
a2He
2
---(rHe) + - - +k H
ar r ar

az 2

e

0

is solved with Dirichlet and/or Neumann boundary conditions.

In both cases, these equations reduce to theeigenvalue problems and both E and H modes can be treated.

Resonance frequencies can be obtained from theeigenvalues, and the electromagnetic fields can be obtained from the eigenvectors or the derivatives of theeigenvectors.
problems.
force.

Several automatic mesh generation programs (MESH2D) are also developed for several typicalUsing plot program (H2DPLOT), calculated results are displayed by the lines of electric or magnetic

These codes, H2DB and HAX, are checked by calculating simple cases which can be solved analytically.

For the axisymmetric case, calculated results by HAX are also compared with those by SUPERFISH. 2 )As forthe resonance frequency and the pattern of the lines of electric force, sufficient agreement is confirmed between
HAX and SUPERFISH.

The computation time by the code HAX was shorter than that by the code SUPERFISH.

Figure 1 shows the calculated results for single gap type resonator for the RIKEN SSe.

Cut-off frequency

and the RF electric field distribution along the accelerating gap are shown.
Recently, radio frequency quadrupole (RFQ) linear accelerator has attached much attention because of new
focusing, bunching and accelerating structure.

Model tests for the RFQ linac resonator were done at the Institutefor Nuclear Study,3) and we calculated the resonance frequencies and the lines of electric force.
the results.
Alvarez type linac resonator was also investigated and the results are shown in Fig. 3.

Figure 2 shows

191

I
r
1 "./ 1
"

(a )

I

:'
(h )

(c 1

I

11111111111111111111111111111111111111111111111111

I
(d l

c1

~
A

@IC

( 9)

-=c 1. 0

(ei

::>

-e

c"",ygoggggyygoyggggyggggggggygg""""""yU

r1

C

B

'"
u

u

ClJ

(fl

w

500
IN J

rJ'y yy""gggg,ggggggggyggggygggg"q""""",yU
Fig. 1.

Calculations for single gap resonators.

DI S I'lnC~( em )

These calculations are done using straight resonatormodel. Only half of the region is analyzed because of the symmetry condition.
(a)Schematic drawing of the single gap resonator designed for the RIKEN SSC.

(b)

The straight resonator model by which fields are calculated.

(c)

Rectangular model. Lines of electric force on the median plane are shown. NP = 1891 (numberof nodal points), T cpu = 127 s (CPU time)/5 modes (FACOM M200), fl c = 33.332 MHz.

(d)

Trapezoid model. Lines of electric force on the median plane are shown. NP = 1891, T cpu = III

siS modes, ftc = 37.283 MHz.
(e)

The model of the single gap resonator for the RIKEN SSC. NP = 1211, T cpu = 56.8 siS modes,
f 1c = 23 .817 MHz.

(f)
(g)

The same model as in (e) with vane attached. NP = 517, T~u= 22.4 siS modes, fl c = 23.360 MHz.

RF electric field distributions along the accelerating gap for the above models . Each distribution
is normalized at maximum.

Cut-off frequencies decrease from model (d) to (f).
(c) to (d).

Electric field at the injection radius increases from

Vane effects are the lowering of the cut-off frequency and the increase of the electric fieldnear the vane.

192

R

o

(1 = 297.5926 MHz

1.4282em

5

•

4

--e 3
CD

cJ 2
( 2 = 1 860.241 MHz

Fig. 2.

F our vane resonator model of the INS RFQ linac.

R ( em)Taking advantage of the symmetry,

only an octant region is analyzed.
(a) Subdivisions. The numbers of nodal points and elements are 428 and 409, respectively.
(b) Lines of electric force shown for H210 mode. Computation time is 45 s for five modes.
(c)

The same for H220 mode.

(d)Calculated electric field distribution along the line OR in (a).
Outer wa ll

Fig. 3.
(a)Alvarez linac resonator

Calculated lines of electric force

for the first cell.

R

The outer radius is

50 cm in length. fIr = 219.89 MHz,r----

f2r = 484.28 MHz.

-

t===:::- ~

(zr

~

(b)

Calculated lines of electric force

for the last cell. The outer radius is
MHz ,Central AXIS 49.38 cm. f lr = 21989.
f2r = 471.32 MHz.

References
1)

M. Hara, T. Wada, A. Toyama, and F. Kikuchi: Sci. Papers I.P.C.R., 75, 143 (1981).

2)

K. Halbach and R. Holsinger: Particle Accelerators, 2, 213 (1976).

3)

N. Tokuda, T. Nakanishi, N. Ueda, S. Arai, T. Katayama, and A. Noda: IEEE Trans. on N.S., NS-28 , 3510
(1981).

193

N -27.

Model Study of RF Resonator for the RIKEN

sseK. Ogiwara , M. Rara , and T. Fujisawa

The resonator for the RIKEN sse is required to work in the frequency range of 17 to 45 MHz
at the voltage of 250 kV (Maximum). In this resonator , the radial distribution of dee voltage isdesired to be constant or radially increasing in order to realize good beam quality. The radial
length of the accelerating gap should be more than 2.6 m corresponding to injection and extraction
radji. In order to find the best structure of the resonator that satisfies the above conditions,calculations with transmission line approximation were carried out for half wave-length typeresonator. From the calculations, it was found that the resonator satisfies the above conditions.
On the basis of these calculations, a half scale model was constructed and the resonance frequencies ,Q-values and radial distributions of RF electric field at the accelerating gap were measured.l) To
realize good radial distribution of RF electric field at the accelerating gap and also to make thesize of the resonator small, earth panels were attached in the model resonator.

Figure I shows

the schematic view of the earth panels inside the model resonator. The resonance frequencies ,Q-values and the radial distributions of RF electric field at the accelerating gap were measured.
Figure 2 shows the radial distributions of RF electric field at the accelerating gap measured byperturbation method. 2) Fairly good radial distributions were obtained at low frequencies (less than
50 MHz for the model) when the earth panels were used.

Short pla t e
Ou te rco nduc tor

o

N

(Y)

A'

o
o
co
(Y)

Pic k up
loop

St em
Sect ion A- A 'Fig. 1.
Schematic view of the earth panels inside the model
resonator. The earth panels were made of 0.3 mm- thick copper
plates.

194

2.5
Frequency = 63.98 MH z
2.0

1.5
Q)

.&

1.0 o-==",~~~~=~------.l--~--------.l

o

>

Q)
Q)

-0

1. 2 ~

Q)>

F =40.22 MHz~.----

I~•

1. 0 r-=·=--""~--.=---==.=""'-""""'------

Q)

0:::

121

----.

F=36.58 MH z·

10 .----.---===~~===---~~·----·-----· I•• •Fig. 2.

12r

F = 31. 03 MH z

field along the accelerating gap for the model

1 0 .----.--==~----~--,·~·-----··I
1

I njec ti on

I~-~-.~

3

5

7

9

I

I

11

13

Pos i t i on along acc ell era ting gap

Relative distributions of RF electricresonator which uses the earth panels.

The

distribution of the electric field at the extraction

Extract ion .

.

radIUS were Improved.

10000

1.0

.---....

With out ea rth pa nels~-~Eeart h panels-:5.------------

•

no
c

Q)

.~

><

Q)
:::)

<tl

0.5

~

a

<tl
0

5000

U

Wit h pane ls~~
0----~----~----7-----~----~--~

OL-____L -_ _~L---~~--~~----~--~
30
40
80
90

Fre quency (MH z)

Freq uency ( MHz )Fig . 3 .

Measured stem length.

Fig. 4.

Measured Q-values.

195

Figure 3 shows the stem length as a function of radio frequency. The stem length could be
reduced by about 40 cm in this model by using the earth panels. This is equal to the 80 cm
reduction in full-scale resonator.
Figure 4 shows the frequency dependence of the Q-values. The Q-value has maximum value
at the lowest frequency when the earth panels are used and makes slow decrease as the frequency
increases as shown in Fig. 4. From the result of these measurement, it was found that a half-wave
type resonator using the movable shorting plates along with movable earth panels for frequency
variation is desirable.

References
1)
2)

M. Hara, K. Ogiwara, and T. Fujisawa: IPCR Cyclotron Progr. Rep., 14, 182 (1980) .
L.C. Maier, Jr. and J.C. Slater: J. Appl. Phys., 23, 68 (1952).

196

N -28.

New Method to Vary Resonant Frequency ofResonator forsse

T. Fujisawa

The resonator for the IPCR SSC has been designed and the results of study by a model have, been reported previously .1) The resonator designed, however, has some disadvantages as follows:1)
2)

The height of the resonator is very high (7 m).
The distance which the shorting plate must travel is long (2 m) .

Consequently , the total

length of resonator including the mechanism to move the shorting plate becomes more than 11 m.
3) The maximum current density at the contact fingers of the shorting plate is estimated to
be 70 A/cm at Vdee (voltage of dee) = 250 kV for 45 MHz. It is difficult to fabricate the fingers
which endure such high current density.
Therefore, a new method to vary the resonant frequency is investigated.
type resonator is shown.
the "movable box".

In Fig. 1, the new

The resonant frequency is varied from 17 MHz to 45 MHz by moving

The box does not make contact with the stem but contact only with theouter wall.

I

B

A- A Cross sect iono~Movab le
box

o

(Y)

I I I Io

I

I! ! ! I I

1000

B- B Cross sec ti on

The gap between the stem and box is 4 cm.

Fig. 1.
Schematic view of the new typeresonator.

This resonator has following merits:

1)
2)

The height is less than 3 m.
The distance which the box is moved is short (0.6 m).

3)

The contact fingers are not at the location where the current density is maximum.

197

Figures 2 and 3 show the characteristics of the resonator calculated by the transmission line
approximation. As shown in Fig. 2 , the power loss at low frequency for V dee = 250 kV is toohigh to realize this cavity. The dotted line in Fig. 2 shows the power loss assuming that therequired dee voltage is proportional to the resonant frequency. In this case the power loss is not
so high. This cavity can be used if high voltage such as 250 kV is not necessary at low frequencies.

AL S = 1.75
He = 1. 33

50

60

Curre nt de nsity( V Dee = 250k V)

HMV = 0.6
DSG=0.04
Loss

E( VDee= 250kV)

50

2x 10 4

400

u

<t:
------0
C
<lJ

<lJ

40

-=:
<U
>I

300

Qj

(j)
(j)

200 ~
~ 20

c

o
(j)

<lJ

0:::

<lJ

-

~

o

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

CL............

1 X 10 4

(j)

""
""
"

/""-

~

30 ?:;(j)C......

<lJ
-0

_//

Curren t density(V Dee = 250 · f/ 45 kV )

20 C

~
::J

U

100

......

10

LOSS/.......... - - - -( VDee= 250 · f/ 45 kV )Di st ance from end of resonatorto movable box (m )Fig. 2.
Resonant frequency (f) andpower loss calculated by the transmission
line approximation. Parameters, ALS,
HC, HMV, and DSG are shown in Fig. 1.
The values of these parameters were

Di stance from end of resonatorto movable box (m )Fig. 3.
Q-value and maximum current
density at the stem end. See the captionof Fig. 2.

determined to give the best characteristicsof the resonator. The power loss iscalculated at Vdee = 250 kV (real line)
and Vdee = 250· f/45 kV (dotted line) .

Reference
1)

E

2

M. Hara, T. Fujisawa, and K. Ogiwara: Proc. 9th Intern. Conf. on Cyclotron and their
Applications, Caen , Sept. (1981).

198

N -29.

Vacuum System of thesse (I)S. Nakajima, K. Ikegami, Y. Oikawa, and I. Takeshita

Design of the acceleration chamber of the IPCR SSC was changed from that previously
reported. 1 ) The volume of the newly designed chamber 2 ) is approximately 65 m 3 . The surface
area exposed to the vacuum is about 750 m 2 , whose composition is as follows:
Materials

Surface area

Stainless steel"-' 300 m 2

Copper"-' 440 m 2

Elastomer~ 5 m2Total~ 750 m 2

Pumping system for this chamber must satisfy following requirements:
1) Opera ting pressure< 1 X 10 - 7 Torr
2) Time allowed for roughing"-' 1 h3)Time allowed to achieve operating pressure"-' 20 h.

The quantity of gas released from inner walls depends on quality and treatments of the surface
materials. It will be 7 '" 16 X 10 - 3 Torr· P/sec after 20 h pumping as is shown in Fig. l.

10 I

o

I-

~102
' (J)
(f)

<U
tl()

:J
o

ro

o

Fig. 1.

I-

The estimated total outgassing

from materials of inner walls of thechamber. The outgassing from anyother materials or components within the

10 3chamber is not included.
O L---------~~~~~~~~~~~~

5

10

Time of evacuation (hours )Outgassing

rates were obtained from the "vacuum
Handbook" published by UL V AC
corporation.

199

In addition, there is a gas load of '" 3 X I 0- 3 Torr· f/sec caused by the evolution of gas fromvarious components within the chamber and the permeation of gas through the sealing elastomers.
Therefore, an effective pumping speed of 11 X 104 l/sec, at least, is required to achieve a pressure
lower than 1 X 10-7 Torr in the chamber. A combination of cryo-pumps and turbo-molecular
pumps seems sui,table for the pumping system to realize this condition. These pumps will belocated in each valley chamber, in each RF resonator and in each space between the main magnet
and the RF resonator. The coarse pumping will be done by four roughing pump units. Each ofthem is consisted of a rotary pump and a roots pump. Two of the units evacuate the RF
resonators and the others evacuate both the valley chambers and the sub-vacuum chambers. A
back up pumping system will be also necessary when one of the roughing units is not operational.
An example of layout of the vacuum system is shown in Fig. 2.
sub- vacuum chambermagnet chamber

I
I

I

*

I 300 m / h ~
3

~

Q

$
I

Q
® c. P. : cryo- pump

0lJJ M. B. : roots pump

~ T. M. P. : turbo - molecular pump

@ R. P. : rotary pump

Fig. 2.

~I 300m 3 / h

@
Z

o
I

®
I

[]
I

Schematic drawing of a possible vacuum system.

References

1)
2)
3)

K. Ikegami, S. Nakajima, and Y. Ikegami: IPCR Cyclotron Progr. Rep., li., 198 (1980).
K. Ikegami, S. Nakajima, Y. Oikawa, and I. Takeshita: p. 200 in this report.
S. Nakajima and K. Ikegami: IPCR Cyclotron Progr. Rep., !±, 195 (1980).

200

N -30.

Vacuum System of thesse (II)K. Ikegami, S. Nakajima, Y. Oikawa, and I. Takeshita

Vacuum chamber for the sse
The design of the vacuum chamber for the sse was changed from the monolithic structure 1 )to the structure divided into 8 sections. One reason is that the RF resonators must be withdrawn(1)

backwards from the stationary position so that tuning and repair can be done easily, and anotherreason is that the operational equipment of the magnetic and electric injection channels, and of thebeam diagnostic device of the injection system must be installed at the central region in theatmosphere.
In narrowly restricted space where bolt-nuts cannot be used, a sealing method with apneumatic expansion seal 2 ) was considered to allow reasonable dimensional tolerances and tosimplify the connecting and disconnecting procedures. This seal is especially adopted for sealing
between RF resonator sections and magnet sections. Valley sections are connected to the magnet
sections by using pneumatic expansion seal or lip welding.
The problem in evacuation is the evolution of gas from the surfaces of the chamber andequipments in it. Because a large quantity of gas is supposed to evolve from the pole faces, themain coils, and the field trimming coils, these components are placed outside of the chamber.
As the space available for the chamber in the pole gap is restricted, the chamber wall in thatspace could not be made thick enough to withstand atmospheric pressure. The chamber at themagnet sections is therefore surrounded with a sub-vacuum chamber which is evacuated to about
10- 1 Torr to lessen the pressure difference on both sides of the wall. The thickness of the wallis 4 mm. The wall is fixed to the pole piece with O-ring seal interposed, by special bolts madeof stainless steel and iron. The analysis of this structural behaviour is in progress using a finite
element method.
The plan view of the chamber is shown in Fig. 1 and the vertical cross sectional view showing
the connection between the magnet and the RF resonator sections in shown in Fig. 2. The
chamber at the magnet section is also seen in this figure.
Geometric characteristics of the chamber are as follows:
total diameterheights:(2)

the valley section

the RF resonator section
the magnet section
the sub-vacuum chamber
total volume
Test of the pneumatic expansion seal

9m
60 cm
740 cm
5 cm

38 cm
65 m 3Three different types of 1/3 scale model of the seal were constructed to investigate theperformance.

Figure 3 shows a photograph of one of the model pneumatic expansion seals.

seal is fabricated by welding together two thin stainless-steel plates shaped like a race-track.

The

201

Fig. 1.

- MEDIAN PLANE _. -Plan view of the vacuum chamber for the sse.

- -- - -Fig. 2.
Vertical cross section of thevacuum chamber showing the method ofsealing between the magnet and the RF
resonator sections.

Fig. 3. A photograph of 1/3 scale model
pneumatic expansion seal.

We measured the expanding length and the applied pressure required for the seal.

Forceapplied to the O-ring is about 9 kg/ cm when a single O-ring is used to seal. It was checked
whether there is any leakage by using a He detector. Figure 4 shows the expanding length of eachseal versus applied pressure. The expanding length of the seal was measured while the pressure was
first increased gradually and then decreased gradually.

202

20

B TYPE
10/=120, T=I. 0(OFF CENTER)
15

i:
~

-.J

<l

:r:

f--

L'1

10 -

W=100, T=I. 0

:z::

w

-.J
(.!J

:!:

;;
Z
c::(

a...

x
w

5 -

W : WI DTH OF THE SEAL
T : THI CKNESS OF THE SEALo
Fig. 4.

1. 0
2. 0
3. 0
APPLI ED PRESSURE (KG/CM 2 )4. 0

The expanding length of three different types ofseals versus applied pressure.
The gap between the magnet section and the RF resonator section is considered to be about
10 mm. As can be seen from Fig. 4 , the pressure of 3.2 kg/cm 2 is needed in the case of A-typeseal at a gap of 10 mm. Applied pressure was decreased gradually to the atmospheric pressure
after the test chamber was evacuated to the pressure of less than 10- 5 Torr. It was found thatthe seal was free from leakage against the variation of the applied pressure.
We conclude from the experimental results that the pneumatic expansion seal is useful for thevacuum chamber of the SSC.
The seal should be tested by repeated contraction and expansion to ensure reliable performanceof the seal without loss of high vacuum-tightness due to fatigue of the material or welds.

References
I)
2)

K. Ikegami, S. Nakajima, and Y. Ikegami: IPCR Cyclotron Progr. Rep. , 14, 198 (1980).
C.l. van Lamp: NAC/AR/80-01 Annual Rep., 3.4, p . 105 (1978).

203

N -31.

The

sse Beam Handling System

T. Inamura, N. Kishida, and H. Saito

A design study of the sse beam handling system from the accelerator to the target areas has
been made by taking into consideration the space available for the planned building. Here we
describe a very versatile system that allows us to make full use of the beam quality regarding energy
definition, time structure, and geometrical extent. Figure I shows the plan view of the system.
In designing the present system, special care has been taken to meet the following
requirements:(1)
Symmetrical placing of standarized ion-optical elements;(2)
Achromatic, doubly telescopic transport;(3)
Monochromatic, doubly telescopic transport with a momentum resolution up to 20000;(4)Isochronous, doubly telescopic transport.

Fig. 1.

The plan view of the beam handling system fromthe sse to the target areas.
the system.

So is the source point of

204

The first requirement obviously makes it easy to design the system and to calculate ion-optics.
This assures that one can easily get any beam at any target station without making further
calculations once he has got a certain beam at a target station. What he needs to know is only
the magnetic rigidity of the beam. One must make every effort to avoid background radiation due
to the stray beam produced during the beam preparation in the sse Facilities. Because of this,
it is essential to have an arrangement which allows easy preparation of the beam for any target
station.
An achromatic, doubly telescopic system is most useful to get a high-intensity beam with aclearly defined geometrical extent at the target. In this mode the momentum spread of the initial
beam does not affect the phase ellipse at the end of the system.
Much higher energy resolution than provided by the sse will be needed, for example, in theexperiments with a high resolution spectrometer. Therefore monochromator systems should beavailable for several target areas.
Time-of-flight experiments require sharp beam pulses. This means that the beam handlingsystem should be isochronous so as to avoid the spreading out in time of the beam pulse due to thefinite momentum distribution.
The design of the beam handling system is based on the following specifications of the beamfrom the sse. Particles: Protons through 238U, maximum magnetic rigidity Bp = 34.58 kG·m
which corresponds to the case of 134.5 Me V /u 12C6+;
Emittance: Between 1 1T and 15 1T mm . mrad in both planes;
Energy resolution: E/6E <: 1000;
Time structure: Repetition rate of beam pulses 17 - 45 MHz, depending on the type of beam;time spread::::::: 200 ps.
Numerical calculations of the system were carried out using the computer code
TRANSPORT. I)
The system consists of 90° bending magnets (B), quadrupole triplets (Q), and switching

It has mirror or anti-mirror symmetry, depending on the target area. Except in
the case of the target area 2, the system works as a double monochromator whose energy
magnets (SW).

resolution is 13000, i.e. 26000 in terms of momentum, when the slit width is 1 mm at the source
point So (See Fig. 1). Isochronous transport to the target areas 3, 4, and 5 is possible.

For

example, the time spread due to the flight from So to the target area 3 is about 70 ps. Achromatic,
doubly telescopic transport is guaranteed except to the target area 1. Figure 2 shows horizontal
and vertical beam envelope plots for a 134.5 MeV /u 12C beam in the case of achromatic, doubly
telescopic transport to the target area 2.
The present design will be modified to meet shielding requirements, to provide more target
stations, and to facilitate future expansion.
Technical data on the ion-optical elements are(1) Bending magnets (B): 90° bending angle, radius p = 2.66 m, pole-face rotation = 26.6° for(2)both entrance and exit sides, pole gap = 7.62 cm, homogeneous field:::; 13 kG;
Quadrupole triplets (Q): outer magnetic quadrupoles of effective length 25 cm, inner magnetic
quadrupoles of effective length 45 cm, drift space between elements = 20 cm, aperture radius= 3.81 cm, maximum field gradient = 1.5 kG/cm;(3)

Switching magnets (SW): double-focussing switching magnets with 0° pole-face rotation andcurved exit face are under consideration.

205

0

~

~

-

~

'"

..

.,

,.;

,

,

'-

g

'f ~

g

N

N

~

~

N

Fig 2.
Horizontal (X) and vertical (Y) beam envelope plots for a 134.5 Me V lu, 15.3
7r mm· mrad 12 C beam from the SSC to the target area 2 in the case of achromatic,
doubly telescopic transport. This emittance is the largest value the beam of which canpass the beamline with an aperture radius of 3.81 cm without hitting the inside wall.

Reference
1)y

K.L. Brown and S.K. Howry: SLAC Report 91, Stanford (1970).

~

206

N-32.

Status of Radiation Shielding for the RIKEN

sse Facility

S. Fujita, S. Yamaji, and T. Shikata

In our previous report ,1) a calculation of the attenuation of neutrons passing through a thick concrete wall
was carried out using absorption coefficients derived from half-value reduction thickness for high energy neutrons
in the concrete .2 ), 3)

However , as the contributions from inelastically scattered neutrons were neglected in ourprevious calculation , and , therefore , it did not include such factors as build-up factors in the absorption coefficient ,it was supposed to be inaccurate.

In the present report , the attenuation of neutrons in a concrete wall including

the effects of inelastically scattered neutrons is re-evaluated using the results of calculations by Alsmiller et a1. 4 )and by Roussin et aI. ,5) and the results are presented in a form available for the design of thickness of shieldingwall.

We assume that the density of concrete is 2.4 g/cm 3 and that the concrete contains 8.5 10 21 hydrogen0

atoms in cubic centimeters.
Their calculations on transport of monoenergetic neutrons normally incident on a semi-infinite thick slab
shield were carried out with the discrete ordinates code ANISN.

Alsmiller et a1. calculated the transport througha thick slab of sillicon dioxide containing 5 % water by weight for neutrons of energies 50, 100, 200, 300 , and 400
MeV , and Roussin et a1. carried out a similar calculation for the case of concrete slab of the same thickness forneutrons of energies 15 , 25 , 50 , and 75 MeV .
The geometrical arrangement used in our calculation for the source and the shield are shown in Fig . 1.
Neutrons are those generated, as before ,1) from the reactions:

1) protons of energy 200 MeV incident on a thickaluminum target ; 2) carbon ions of energy 135 MeV / A incident on a thick iron target; in both cases, beam currents
are assumed to be 1 particle pA .
( b)

(a)

------Be am Direc tion

Fig. 1.
(a)\\

SourceBeam Direct ion

Sou r ce

Geometrical arrangement used for the calculation:hemi-spherical covering for the calculations of attenuation ofneutron flux;(b)cylindrical covering for the calculation of skyshine.

To begin with, in our shielding calculation , relation between neutron dose equivalent and depth into concreteslab is required for neutron energies up to 200 MeV.

Then the ratio of the dose equivalent in the concrete slab

with respect to that in silicon dioxide slab as a function of the depth was obtained by the results of Alsmiller
et a1. and of Roussin et a1. at the incident energy of 50 MeV.

We obtained the attenuation curves in the concreteslab for the incident energies of neutrons up to 200 MeV , multiplying the curves for the corresponding energies insilicon dioxide slab by the ratio obtained above.

To make use of these curves for the calculation of attenuationof neutrons ejected from a point source, the following approximate expression of the dose equivalent DB at the outersurface of a spherical covering of thickness d for a monoenergetic point source with strength ¢o (n/sr) was derived:

cPO

R2

DB = DB'RZ (R + d ) 2 '(1)

where, as shown in Fig. l(a), R is the radius of the inner surface of the spherical covering, DB' is the dose

207

equivalent at the depth d into the thick concrete slab for the case of the parallel neutron flux of density one
neutron/cm 2 normally incident on it as obtained above. Calculating the quantities DB for neutrons of various
energies and summing them up , we obtained the dose equivalent on the outer surface of the spherical covering forthe point source of neutrons ejected by the reactions mentioned above.

If the directions of neutrons passing

through the concrete covering are assumed to be unaltered from their initial directions, the dose equivalent at
distance r (r 2 R + d) is easily determined.

These results are shown in Fig. 2 together with the previous results.

By means of these curves, one can easily design the shielding.
using materials of high density .

The thickness of concrete wall can be reduced byThen, after Smith,6) we also get a dose-geometry contours for the design of abeam damp with iron and concrete.

An example of such contours is shown in Fig. 3.

"\..

'\.

C\.

"

,

~

1',

-

------ A

I\.

'i\.
"\..

,,'\."\..

~

I\, ~

"'"

1'1\.

,

'\

' ~ '\ " ,---V p' 1\." ~'...

,,' ..... ' ...'.
...

,

'\.

'\.'\.

."\..

"\..

,~

... "

"

...

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

'.

I'

"

" "

.'\.

'V

\; ~~
'

.. ...
"~8-40'~,-,.. '\..

'\.

8= 0'-20'

I
8 20'

40'

./

./

I'\..

'~/

"\..
~,

"' "\ ,
1'\..','\.

" , , "'I\.

",> ~~ '\.. , '\,X k", .'\l'- 1\ '\r\.

1', ~,-~," ....--"''I"'\.

..., " ...
"

-

-

--- B

" '"

.. ' .
"""... ..
-'",60' ..-

/

"

~,

,

'.

' ... "'\
8=60'-120' ... ~- ~, X'.l\.
r\.~ , . ,I\.
...,,,~~ ~,1\.' ...,",

1-1JO' 180'

"\..

:::::

Y""I\..

, ,"O. }I---+-I--It+---+-+-+--.-++--+-----,p.-----l...., , '. ,r. "\..
,, ' ... '1'01'1\.',,,
, ,~
"

Depth

'\.'.

...

' ...

'\..

'\..

"~
'..:

0.0 1 L....-...!....L..--l.2-3L..-...I..4----'-J5--'--~6.L--J..--'"
7

into concrete wall ( m )Tc

Fig. 2.

Dose rate multiplied by r2 vs.

depth into concrete covering.

Fig. 3 .

( m)

Dose-geometry contours for

200 MeV protons (lJ.lA) on a thick Al
target (0 _20°). Here, r F is the
thickness of the iron traversed, re is
the thickness of concrete traversed,
along a radius from the neutron source
to the point of evaluation of the dose
rate D, and r C + F is equal to r F + rc'
Xc is the thickness of concrete in mean
free paths.

This contour expresses therelation between dose rate D andthickness rc with r F or rC + F asparameters. It is required that Xc be
greater than 3, so that neutron equilibrium
can be established in the concrete .

208

Calculation of the sky shine for a point neutron source enclosed by a cylindrical covering as shown in Fig.
1(b) was carried out by inse rting the results shown in Fig. 2 into the empirical equation of Thomas. 6 )are shown in Fig. 4 together with the previous results.!)

The results

One can estimate the width of the roof required forgetting seve re condition of radiation level at the boundary with inhabitants at a distance of 100 m from thesource as 4.5 m.

This is for the extreme case that the machine is operating for 5000 h per year continuouslywith the maximum beam energy and beam intensity of 1 particle IlA and that the shielding is performed only with
However as beam damps are set at each terminal of the beam transport systems , the width of the roof

the roof.

might be considerably reduced.

~~

10 2

~

------ A

~

;-

--- B

3m

...........

1"0... ........

",~.

~' :'...

10 I..........

5m

I

"

"

"

ft.~';,.,~,. ....

" ~ ' ...

".......

~ 10-....

......

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

, /.......
too ....

~-... .....

I't.....

". """'-~

1""'0...

""'",

~

.

~

'

' ....

""'..... .....-~

....

~

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

. . :-....

'. ,......, .... ....... ........ ~t-.....
"', .. ........
"'-

1'-

2

........

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

/:"~...

""

10 0

- --

.....

" ~,.... ..... ..... ..../...
~

5 mre m/ y

( 1 y = 5000h ), .... ...
"- '" .... '.
............. ...

4m

a

,
"- , I"- ......... .....

....

"

'".....

. ...r-...
.....
,- , :::::.......::::-~ ........

~t.....

.... .......

.. r.. ....

--1'" .....

100
200
300
Distance from neut r on sourc e (m ).... ..

.....

Fig. 4.
Spatial distribution of neutron
skyshine. Upper curves of each group...

with two curves correspond to the400

attenuation length A = 850 m and lower
ones correspond to A = 267 m .

As is seen from Figs. 2 and 4, the radiation levels of the present results which include the effects ofinelastically scattered neutrons are considerably higher than those of the previous results as was expected .
However , in our present calculation , following several problems remain: 1) removal of the contribution due to thebackscattered neutrons from the results; 2) consideration of the effect of the extremely large components at forward
angles of the angular distribution of the source neutrons on Eqns . (1), and 3) improvement of the empirical equationof Thomas . When these problems are settled the required thickness of the shielding might be reduced to some extent.

References
1)

S. Fujita , S. Yamaji, and T. Shikata: IPCR Cyclotron Progr. Rep., .!.±, 203 (1980).

2)
3)

R. Wallace: Nucl. Instr. Methods, 18-19,405 (1962).
H.W. Patterson and R.H. Thomas: "Accelerator Health Physics", Academic Press, p. 442 (1973) .

4)
5)

R.G. Alsmiller, Jr. , F.R. Mynatt, J. Barish, and W.W. Engle , Jr.: Nucl. Instr. Methods, 72, 213 (1969).
R.W. Roussin , R.G . Alsmiller, Jr. , and J . Barish: Nuc!. Eng. Design , 24, 250 (1973).

6)

H.A. Smith: IUCF Internal Rep. , No. 74 - 6 (Radiation Shielding Note 1) (1974) .

209

N -33.

Status of the Prototype Baby Cyclotron

T. Karasawa and T. Nozaki

In this year) the Prototype Baby Cyclotron at the National Nakano Chest Hospital in Tokyo
has been operated for the production of ultra-short lived radioisotopes (ll C, 13N , and 15 0). At
the Muroran Plant of JSW Ltd and the Sano Plant of IDX Co. , improvements on mechanical andelectronical systems, respectively , were carried out successfully in manufacturing commercial type
Baby Cyclotrons. These improvements made primarily for commercial type machines have also
been applied to the prototype machine for higher beam intensities and for easy change of theacceleration particles from proton to deuteron.
The prototype machine was overhauled twice in the year.

In the spring overhaul , new dees

and dummy dees (each plate against dee) were installed; in the autumn overhaul, the handlingdevice and center plug of lower magnetic pole were changed to those used in the commercial type
machine.
Performance of the ion source for doubly charged helium ion (~-particles and 3He++) was
studied. It is well known that beam intensities of the multi-charged heavy ions increases withincreasing arc power (arc current multiplied by arc voltage) and with decreasing gas pressure when
the gas flow is enough to maintain the arc discharge. Our experimental results agree with these
80
50

-I

VA
350 V
l::. 250 V
x 150 V

30

x

0

1

':? 20
.::t

E

<"IJ

5

gas f I ow rate
3mt/min

OJ

OJ

10
x

2

7

x

1

50

IX
100

Arc Power [VAX ]A] [W]

Gas f low rate [ ml/min]Fig. 1.
Comparison of beam intensities
between d and ex-particles. I is the beam
intensity at 20 cm radius for the same ion

Beam intensities at 10 cm
Fig. 2.
radius vs. gas flow rate
Arc voltage: 250 V

source and the same acceleration conditionso (real):

2.8 A arc current

X (broken):

1.6 A arc current

6. (real):

0.6 A arc current

except the magnetic field.

210

general tendencies, as shown in Figs. 1 and 2.

This experimental result is useful in the 18F

production by the nuclear reaction 160eHe, p)18F on a natural water target as well as in activation
analysis of oxygen by the same reaction.
Beam intensity distribution at the entrance window of the target box is critical in gas target
bombardment.

Autoradiographs of copper plates bombarded at this position were observed by adensitometer to give isodensity curves.

A result is shown in Fig. 3 and Table 1.

ver tical\j

+6
+4
+2

-

horizontal

0

- 2
-4
-6
+ 4 +6 ( mm )Fig. 3.

Isodensity curve at the target box.

Table l.

Beam distribution at the target box.
a

b

c

d

Beam in tensi tya)

68 %

45 %

23 %

10 %

Beam concentration b )25 %Beam densityc)

20 /lA/cm

45 %2

11 /lA/cm

70 %2

7 /lA/cm

90 %2

4/lA/cm 2a) Relative to peak intensity at the position of cross in Fig. 3.
b) Concentrated beam inside isodensity curve.
c) Average density between isodensity curves.

Routine diagnostic use of l1eo and l1eo 2 has been continued.

Photosynthesis mixture ofl1e glucose and fructose has been produced routinely and used for lung cancer identification andfor some other purposes.

An automatic synthesizer of this product is under construction and will

be completed by the end of January, 1982.
The Kiliani synthesis of l1e-labelled glucose-mannose mixture has been studied.

By the useof glucose and mannose labelled with 14e at the carbonyl positions, the l1e Kiliani synthesis
mixture was shown to be almost equally effective for the study of brain functions as l1e glucose
after being separated from the mixture.

A process suitable for automated synthesis of the l1e

glucose-mannose has been established, and the automatic synthesizer has been designed.

211

Preparation of (l1C-methyl)-stearic acid from 11CH 3 I by the malonic acid synthesis has beenstudied.

Hexacosanoic acid labelled with 11e at the carboxylic carbon was prepared both by the

Grignard reaction and the nitrile synthesis. The behaviour of this compound was studied for its
possible use as a diagnostic tool for adenoleukodistrophy. 1)
Aspartic acid labelled with no-carrier-added 11e was prepared by the following two-step
enzymatic synthesis: (1) reaction of 11e0 2 and phosphoenolpyruvic acid in the presence ofphosphoenolpyruvate carboxylase to give 11e oxaloacetic acid, and (2) conversion of the oxaloacetic
acid into aspartic acid- 11 e with the aid of glutamic acid and glutamate-oxaloacetate transaminase.

In vivo distribution of this compound and catabolic rate of the HC atom into expired air werestudied. Its diagnostic use is under consideration.

ReferenceI)

N. Sakuragawa, A. Matsui, M. lio, S. Eda, T. Nozaki, M. Arima, E. Satoyoshi, and T. Karasawa:
Intern. Symp. Leukodistrophy and Allied Diseases, Tokyo, Sept. (1981).

212

V.

RADIA liON MONITORING

1.

Routine Monitoring

M. Koyama, K. Igarashi, 1. Usuba,
S. Fujita, and 1. Sakamoto

Results of routine radiation monitoring carried out on the cyclotron from April 1980 toMarch 1981 are described.
No remarkable change in leakage radiation and residual activities was observed during thisperiod.

Some aspects of the leakage radiation are described in the following report.
(1) Surface and air contamination
The surface contamination has been kept below 10 - 6 pCi/ cm 2 on the floor of cyclotron roomand the underground passage, and below 10- 7 pCi/cm 2 in the experimental areas, hot laboratory
and chemical laboratories.

The contamination was wiped off twice a year, and immediately after

this decontamination, the contamination on the floor of cyclotron room and the undergroundpassage had been reduced to a value below 10- 7 pCi/cm 2 .
When the accelerating chamber was opened, slight contamination of the air in the cyclotronroom was observed. The value of radioactivity concentration (beta-gamma) was 10- 12 pCi/ cm 3 .
(2) Drainage
The radioactivity concentration of the drain water from the cyclotron building was found to
Table 1. Annual exposure dose received by the cyclotron
workers from April 1980 to March 1981.
Collective

Number of persons
WorkersDose

10 -1 00

101-300>300

undetectable(mrem)(mrem)(mrem)

Operators

Total

dose
(man-mrem)

7

8

220

Nuclear physicists

12

3

15

30

Accelerator physicists

17

3

20

120

Physicists in other fields

25

2

28

340

Nuclear chemists

6

4

15

1170

Biological chemists

6

6

Health physicists

5

5

Total

72

A verage annual dose per person: 19.4 mrem.
Maximum individual annual dose: 310 mrem.

19

5

5

97

1880

213

be of the order of 10- 6 - 10- 7 J.1Ci/cm 3 • The total quantity of activities in the aqueous effluentsin this period was about 50 J.1Ci, and the radioactive nuclides found by the ')'-ray spectrometry weremainly 65 Zn, 22Na, and 58Co.
(3) Personnel monitoring
The external exposure dose to personnel was measured with ,),-ray and neutron film badges.
The dose received during the present period by all the cyclotron workers is shown in Table 1.
The collective ,),-ray dose to all workers was 1880 man-mrem, while the collective dose owing tothermal and fast neutron exposures was too small to be detected. The collective dose to thecyclotron workers is about 82 % of the value in the preceding period.
In this period the average annual dose per person was 19.4 mrem, and the maximum
individual annual dose was 310 mrem.

214

V -2.

leakage-Radiation Measurement at theUnderground Passage

I. Sakamoto

Leakage radiation during operation of the cyclotron at the underground passage of thecyclotron building was measured. Leakage doses received from April 1980 to March 1981 by
Table 1.

Leakage radiation dose (in mrem) at the undergroundpassage from April 1980 at March 1981.

2

Radiation
I-rays (mrem)

2490

60

Thermal neutrons (mrem)

650

10

Fast neutrons (mrem)

740

60

Total (mrem)

3880

130

a) See the figure shown below.

!

!

!

!

!

!

o 1 2 345m

Experimental area (L)I: 2 x-l..----..........,......................
I

I
I
I

Undergroundpassage~
I
I

Hand foot cloth
monitorControl room216

'Y-ray and neutron film badges which were left at the underground passage, are shown in Table 1.
The machine time allotted for deuteron acceleration was 36 h in this period.
As to the dose values at point No. I measured every month, the maximum dose of 790 mrem
was observed in November. In this case, the values of gamma dose, thermal neutron dose and fastneutron dose were 460 mrem, 80 mrem and 250 mrem, respectively.
The neutron doses observed at point No. I in October, November, and March were larger thanthose in other months. The sum of neutron doses measured in the three months was 770 mrem ,which was 55 % of the total neutron dose in this period. As a result of investigation, it was
concluded that the increase of the neutron dose was mainly due to the 40 MeV a-particle
bombardment on a GaAs and Sn plate at about 5 - 15 IlA in the beam course No.2, where 5 -10
mCi of radioisotopes were produced in each month above mentioned by 75 As(a, 211) 77Br and117Sn(a, 2n)119mTe reactions.

216

V -3.

Examination of Shielding Performance of Doorsin the Linac Building

I. Sakamoto, M. Odera, Y. Chiba, M. Hemmi,

A. Shimamura, T. Inoue, I. Takeshita, and T. Hamada

The shield walls provided for the linac and the associated equipments are made of ordinary
concrete of thickness 15 - 60 cm and able to keep the outside radiation levels ('Y-rays plus
neutrons) below the permissible value for non-occupational people even when a thick iron target
is bombarded by carbon ions of 50 MeV at a current of 2 X 1013 ions per sec.

The entrances tothe injector vault, the accelerator vault and the experimental areas are equipped with shield doors
which are made of ordinary concrete and of iron.
We examined all the six shield doors in the linac building, and found that they had the
expected shielding performance. Details of the examination of the largest door are described
below as an example.
The plan of the door and the arrangement for the measurement are shown in Fig. 1. 30
points were marked on the door as shown in Fig. 2 and at each point the transmission of 'Y-rays
from a 29 mCi 137 Cs source was measured with a scintillation survey meter located at the opposite
side of the door to the source and at a distance of 110 cm from the source.
The distribution of the measured dose rate is shown in Fig. 2. The door is made of 2.4cm
thick iron and of 37.6cm thick ordinary concrete. The calculated dose rate, in this arrangement,
is 0.057 mR/h. While the measured values of leakage dose rate almost agreed with calculated ones
at right, those at left showed gradual increase with, which would be due to scattered 'Y-rays throughopening between the door and the wall.
Since the main purpose of the examination was to check the presence of any defect such asholes in the concrete cast into the door, it is concluded that the door has the shielding performance
expected.

15001

3~0

~~~""/"7""7"7H~/7""((:h-7-7-i~
"'T/

15001
,. ,. . ,.~W~&~L-r"'7;L~~~§[~~Q?f~
[

4

000

[

Cs- 137 source

D
SCINTILLATIONSURVEY METER

Fig. 1.
Plan of the shield door (above) and thearrangement for the measurement (below).

217

6
Unit: mR/ h
X : measured points
x

4

x

E
1:

.~

x

I

3

Q)

I

x

2

\

x

~~
0
0

x

x

x

x

x

x

x

x

x

x

~J

x\x

cs

x

x

x

x

0°

~

x

X

2
Width ( m)3

4

Fig. 2.
Distribution of themeasured dose rate of the shield
door.

218

VI.

LIST OF PUBLICATIONS

1.

Machine development and accelerator physics
1)
2)

H. Kamitsubo: "IPCR Heavy Ion Accelerator Project. The Design of the Riken
Separated Sector Cyclotron", Reports I.P.C.R., 57,131 (1981).
Y. Obana, S. Motonaga, T. Wada, Y. Tanaka, and H. Takebe: "Design of the Sector

3)

Magnet for the RIKEN SSC (II)", Reports I.P.C.R., 57, 147 (1981).
S. Motonaga, T. Wada, Y. Obana, Y. Tanaka, and H. Takebe: "Design of the Sector
Magnet for the RIKEN SSC (Ill). Final Design of the Magnet Pole Using a Computer

4)

Code Trim in 2-dimensional Approximation", Reports I.P.C.R., 57,156 (1981).
A. Goto, H. Takebe, S. Motonaga, T. Wada, Y. Yano, N. Nakanishi, and Y. Tanaka:"Optimization of Currents and Configurations of Trim Coils for Sector Magnet",

5)
6)
7)
8)
9)
10)
11)
12)
13)
14)

15)
16)
17)
18)

Reports I.P.C.R., 57, 165 (1981).
H. Takebe, T. Wada, I. Takeshita, S. Motonaga, 1. Fujita, and Y. Tanaka: "Model Testof Trim Coils for Sector Magnet", Reports I.P .C.R., 57, 171 (1981).
Y. Ikegami, T. Wada, M. Hara, and S. Motonaga: "Structural Analyses of Sector Magnet
by a Finite Element Method", Reports I.P.C.R., 57, 177 (1981).
N. Nakanishi: "Programs for Calculating Beam Orbits in Cyclotron (I)", Reports
I.P.C.R., 57,189 (1981).
A. Goto: "Programs for Calculating Beam Orbits in Cyclotron (II)", Reports I.P.C.R.,
57,203 (1981).
K. Ogiwara, M. Hara, and T. Fujisawa: "Design Study and Model Test of RF Resonator
for the RIKEN SSC", Reports I.P.C.R., 57, 222 (1981).
S. Nakajima, K. Ikegami, Y. Oikawa, and I. Takeshita: "Design of the Vacuum Systemof the RIKEN SSC", Reports I.P.C.R., 57, 232 (1981).
S. Fujita, S. Yamaji, and T. Shikata: "Neutron Shielding for the RIKEN SSC", Reports
I.P .C.R., 57, 239 (1981).
N. Nakanishi, A. Goto, and Y. Yano: "Isochronous Magnetic Field in a SSC and the
Effect of Field Imperfection", Sci. Papers I.P.C.R., 75, 136 (1981).
M. Hara , T. Wada, A. Toyama, and F. Kikuchi: "Calculation of RF Electromagnetic
Field by Finite Element Method", Sci. Papers I.P.C.R., 75, 143 (1981).
Y. Yano, H. Takebe, S. Motonaga, T. Wada, 1. Fujita, and A. Goto: "Design and Model
Study of Injection Bending Magnet for the RIKEN SSC", Sci. Papers I.P.C.R., 75,176(1981).
H. Takebe, Y. Yano, S. Motonaga, T. Wada, J. Fujita, and Y. Ikegami: "Model Studyof Magnetic Inflection Channel for the RIKEN SSC", Sci. Papers I.P.C.R., 75,193 (1981).
A. Goto, Y. Yano, and N. Nakanishi: "Design of Injection and Extraction Harmonic
Coils for the RIKEN SSC", Sci. Papers I.P.C.R., 75, 204 (1981).
N. Kishida and Y. Yano: "Beam Transport System for the RIKEN SSC (II)", Sci. Papers
I.P.C.R., 75, 214 (1981).
T. Inamura, N. Kishida, H. Saito, and M. Watanabe: "The RIKEN SSC Beam Handling
System", Sci. Papers I.P.C.R., 12 236 (1981).

219

19)

S. Motonaga, T. Wada, Y. Yano, H. Takebe, J. Fujita, Y. Ikegami, and N. Nakanishi:"The Sector Magnet for the IPCR SSC", IEEE Trans. Mag., MAG-17, 1836 (1981).

2.

Nuclear physics and nuclear instrumentation
1)

2)

M. Ichimura, E. Takada, T. Yamaya, and K. Nagatani: "Reaction Mechanism of
12C(160, a): 12C Transfer to Nuclear Molecular Resonances", Phys. Lett., 101B, 31(1981).
H. Utsunomiya, T. Nomura, M. Ishihara, T. Sugitate, K. Ieki, and S. Kohmoto:"'Angular-Momentum Transfer and Alignment Following Preequilibrium a-Particle
Emission in the Reaction 209Bi + 14N", Phys. Lett., 105B, 135 (1981).

3)

S. Yamaji, A. Iwamoto, K. Harada, and S. Yoshida: "Microscopic Calculation of theMass Diffusion Coefficient Using Linear Response Theory", Phys. Lett., 106B, 443(1981).

4)

Y. Gono, K. Hiruta, T. Nomura, M. Ishihara, H. Utsunomiya, T. Sugitate, and K. Ieki:"In-Beam a- and 'Y-Ray Spectroscopy for 214Rn", J. Phys. Soc. Japan, 50, 377 (1981).
T. Fujisawa, N. Kishida, T. Kubo, T. Wada, Y. Toba, T. Hasegawa, M. Sekiguchi, N.
Ueda, M. Yasue, F. Soga, H. Kamitsubo, M. Nakamura, K. Hatanaka, Y. Wakuta, T.
Tanaka, and A. Nagao: "Analyzing Power-Polarization Inequality in the Inelastic
Scattering of Protons on 12C for Incident Energies from 22.0 to 29 .0 MeV", J. Phys.

5)

Soc. Japan,2Q, 3198 (1981).
6)

H. Amakawa, A. Mori, H. Nishioka, K. Yazaki, and S. Yamaji: "Adiabatic
Approximation for Deuteron Breakup Effect", Phys. Rev. C 23, 583 (1981).

7)

M. Koike, K. Komura, H. Kawakami, M. Kanbe, G. Madiueme, S. Shibata, T. Fujisawa,and T. Wada: "Electric Monopole Transitions between 0+ States in 102Ru", Phys. Rev.
C 24,1611 (1981).
A. Ichimura and M. Ichimura: "Coupled Channel Analysis for the Anomaly of the(180, 18 0*) Reaction", Prog. Theoret. Phys., 66, 913 (1981).

8)9)

M. Kawai, M. Ichimura, and N. Austern: "On the Relation between the Method of

10)

Coupled Channels and the Truncated Channel Coupling Array Formalism for
Rearrangement Reactions", Z. Phys. A - Atom and Nuclei, 303, 215 (1981).
T.Inamura: "Is Massive Transfer Preequilibrium ?", Soryushiron Kenkyu, 63, CI09
(1981).

3.

Atomic and solid-state physics
1) H. Tawara, K. Ishii, and Y. Awaya: "Excitation, Ionization and Charge Transfer
Processes about Inner-Shell Electrons", Atomic Physics by Using Accelerators, Study
Group of Fundamental Atomic Process, p.25 (1981).
2)

Y. Awaya: "Table of Accelerators Used for the Study of Atomic Physics", Atomic
Physics by Using Accelerators, Study Group of Fundamental Atomic Process, p. 91(1981).

3)

Y. Awaya, H. Kumagai, and Y. Tendow: "An X-ray Crystal Spectrometer", The
Handbook of Atomic Collisions - Apparatus -, Study Group of Fundamental Atomic
Process, p. 194 (1981).

220

4)

T. Tonuma , A. Yagishita , M. Kase, T. Kambara , Y. Awaya , and I. Kohno: "Multiple
Ionization of Gas Targets by Ion Bombardment" , Atomic Collision Research in Japan
Progress Report, No.7, p . 76 (1981).

5)

T. Kambara , Y. Awaya , A. Hitachi, M. Kase , I. Kohno , and T. Tonuma: "X-Rays from
Radiative Electron Capture Induced 110-MeV Ne-Ions", Atomic Collision Research in

6)

Japan Progress Report, No.7 , p. 78 (1981).
E. Vagi , A. Koyama, H. Sakairi, M. Iwaki , and R.R. Hasiguti: "Lattice Location of
Ni Atoms Implanted into Al Crystals as Investigated by Means of Channeling Method" ,J. Phys. Soc. Japan, 50 , 873 (1981) .

7)

H. Sakairi , E. Vagi, A. Koyama, and R.R. Hasiguti: "Atomic Replacement in Ordered
Cu 3Au Alloy Irradiated with Protons, a-Particles and Carbon Ions from a Cyclotron" ,J. Phys. Soc. Japan, 50 , 3023 (1981).

8)

H. Kirihata and M. Uda: "Externally Quenched Air Counter for Low-energy Electron
Emission Measurements", Rev. Sci. Instr. , 52 , 68 (1981).

9)E. Vagi , H. Bossy , K.P. Doring, M. Gladisch , D. Herlach, M. Matsui , H. Orth , G. zu
Putlitz , A. Seeger, and 1. Vetter: "Longitudinal Muon Spin Relaxation in a-Iron inHigh Magnetic Fields" , Hyperfine Interaction , ~, 553 (1981).

10)

11)

12)

H. Endo. M. Uda, and K. Maeda : "Influence of the Chemical Bond on the Intensities
of F Ka X-Ray Satellites Produced by Electron and Photon Impacts" , Phys. Rev. A 22,
1436 (1981).
M. Uda , H. Endo , K. Maeda , Y. Sasa , and M. Kobayashi: "Chemical Effect on F Ka
X-Ray Satellites Produced by 6 MeV/amu P, 0: and C4+" , Z. Phys. A - Atom and Nuclei ,300, 1 (1981).
A. Yagishita: "Ionization Cross Sections of Krypton M-Subshells by Electron Impact" ,Phys. Lett. , 87A, 30 (1981).

13)

4.

A. Yagishita , H. Hanashiro, S. Ohtani, and H. Suzuki: "The Kr M2, 3M4SN23 CosterKronig Processes Following Electron Impact Ionization", J. Phys. B, i±, L 777 (1981).

Radiochemistry , radiation chemistry and radiation biology
1)

T. Nozaki, T. Karasawa, M. 10, K. Imamura, S. !ida, and H. Yoshida: "Present Status
in the Use of the Prototype Baby Cyclotron", J. Label. Compo & Radiopharm. , !..§.,
181 (1981).

2)

T. Nozaki and M. Iwamoto: "Some Fundamental Data Concerning the Formation of3)

Low Z Radionuclides", J. Label. Compo & Radiopharm., ~, 230 (1981).
T. Nozaki and M. Iwamoto: "Yield of 140 for the Reactions 14N(p , n) 14 0 ,12CeHe , n) 140 and 12C(a, 2n) 14 0" , Radiochim. Acta, 29, 57 (1981).

4)

H. Muramatsu, H. Nakahara, and M. Yanokura: "Production of 119mSn by Alpha
Particle Bombardment of 116Cd and Its Carrier-free Separation" , J. Inorg. Nucl. Chern.,
43 , 1727 (1981).

5)

F. Ambe and S. Ambe: "A Site Distribution of Dilute 119Sb and 119m Te on
Solidification of SnTe and SnSb by Mossbauer Emission Spectroscopy of 119Sn", J.
Chern. Phys., 75, 2463 (1981).

221

6)

T. Tonuma, Y. Awaya, T. Kambara, H. Kumagai, M. Kase, A. Yagishita , and I Kohno:"Krypton KB/K(X Intensity Ratios for 6 MeV /amu Ion Bombardment", Inner-Shell and
X-ray Physics of Atoms and Solids , Prenum Press, New York and London , p. 153(1981).

(Papers Presented at Meetings)
1.

Machine development and accelerator physics
1) N. Nakanishi , T. Wada , A. Goto, Y. Yano, S. Motonaga, and H. Kamitsubo: " Orbit
Analysis 4 in the IPCR SSC", 36th Ann. Meeting of the Phys. Soc. Japan, Hiroshima,Mar. (1981).
2)

A. Goto, Y. Yano, T. Wada , and N. Nakanishi: "Orbit Calculation of the Injection
System for the RIKEN SSC", 36th Ann. Meeting of the Phys. Soc. Japan, Hiroshima,
Apr. (1981).

3)

M. Hara, T. Wada, T. Fujisawa, and K. Ogiwara: "Three Dimensional Analysis of RF
Electromagnetic Field by Finite Element Method" , 36th Ann. Meeting of the Phys. Soc.
Japan, Hiroshima, Apr. (1981).

4)

M. Hara, T. Wada, M. Odera, and F . Kikuchi: "Calculation of RF Cavities with Axial
Symmetry by Finite Element Method", 6th Meeting on Linear Accelerator in Japan,
Sapporo , July (1981).
Y. Yano, N. Kishida, H. Takebe , A. Goto , T. Wada, and S. Motonaga: "Beam Injection
and Extraction System for the IPCR SSC", 9th Intern. Conf. on Cyclotrons and their
Applications, Caen, France, Sept. (1981).
A. Goto, Y. Yano, N. Kishida, N. Nakanishi, and T. Wada: "Calculation of Injection
and Extraction Orbits for the IPCR SSC", 9th Intern. Conf. on Cyclotron and their
Applications, Caen, France, Sept. (1981).

5)

6)

7)

8)
9)
10)

11)
12)

13)

S. Motonaga, H. Takebe, T. Wada, A. Goto, J. Fujita, Y. Oikawa, I. Takeshita, and Y.
Ikegami: "The Sector Magnet for the IPCR SSC", 9th Intern. Conf. on Cyclotron andtheir Applications, Caen, France, Sept. (1981).
N. Nakanishi, A. Goto, Y. Yano, and T. Wada: "Beam Dynamics for the IPCR SSC" ,9th Intern. Conf. on Cyclotron and their Applications, Caen, France , Sept. (1981).
M. Hara, T. Fujisawa, and K. Ogiwara: "The RF System for the IPCR SSC", 9thIntern. Conf. on Cyclotron and their Applications, Caen, France, Sept. (1981).
T. Fujisawa , M. Hara, and K. Ogiwara: "Method to Vary Resonant Frequency ofResonator of IPCR SSC", 1981 Fall Meeting of the Phys. Soc. Japan, Matsue, Sept.
(1981).
N. Nakanishi , A. Goto, and Y. Yano: "Orbit Analysis 5",1981 Fall Meeting of the
Phys. Soc. Japan, Matsue, Oct. (1981).
A. Goto, H. Takebe, S. Motonaga, T. Wada, Y. Yano, and Y. Tanaka: "Design of the
Trim Coils for the RIKEN SSC", 1981 Fall Meeting of the Phys. Soc. Japan, Matsue,
Oct. (1981).
M. Hara, T. Wada, T. Fujisawa, K. Ogiwara, and F. Kikuchi: "Calculation of RF
Electromagnetic Field by Finite Element Method", 1981 Fall Meeting of the Phys. Soc.
Japan, Matsue, Oct. (1981).

222

14)
15)
16)

2.

T. Inamura, N. Kishida, and H. Saito: "A Design Study of the RIKEN SSC Beam Handling
System", 1981 Fall Meeting of the Phys. Soc. Japan, Matsue, Oct. (1981).
Y. Yano, A. Goto , N. Nakanishi, T. Wada , and N. Kishida: "Beam Centering in the SSC",
1981 Fall Meeting of the Phys. Soc. Japan, Matsue, Oct. (1981).
M. Hara , T. Wada , and A. Toyama: "Calculation of RF Electromagnetic Field by Finite
Element Method", Meeting on Calculation of Electromagnetic Field by Computer, Wako,
Nov. (1981).

Nuclear physics and nuclear instrumentation
1)

T. Inamura : "Is Massive Transfer Preequilibrium?" , Symp. on Transport Phenomena in
Heavy-Ion Reactions, INS , Tokyo , Feb. (1981).

2)

T. Nomura: "Fast Light-Particle Emission and Preequilibrium Phenomena", Symp. on

3)

Heavy-Ion Nuclear Reaction, Tsukuba, Mar. (1981).
T. Inamura: "Massive Transfer" , Symp. on Heavy-Ion Nuclear Reactions , Tsukuba,Mar. (1981).

4)

5)

6)
7)

8)

9)

T. Fujisawa, N. Kishida, T. Kubo, T. Wada, T. Hasegawa , M. Sekiguchi, N. Ueda, M.
Yasue, F. Soga , H. Kamitsubo , M. Nakamura, K. Hatanaka, Y. Wakuta , T. Tanaka,
A. Nagao, and Y. Toba: "Analyzing Power-Polarization Inequality in the Inelastic
Scattering of Protons on 12C for Incident Energies from 22.0 to 29.0 MeV", 36th Ann.
Meeting of the Phys. Soc. Japan, Hiroshima, Mar. (1981).
A. Ichimura and M. Ichimura: The Normalization of the Channel Coupling Effect to
the Optical Potential in Heavy-Ion Inelastic Scattering", 36th Ann. Meeting of the
Phys. Soc. Japan , Hiroshima, Mar. (1981).
S. Yamaji, A. Iwamoto , K. Harada , and S. Yoshida: "Numerical Analysis of the 63Cu
+ 197 Au Reaction", 36th Ann. Meeting of the Phys. Soc. Japan , Hiroshima, Apr. (1981).
Y. Nagame, 1. Kohno, M. Yanokura, H. Nakahara, H. Kudo , and K. Sueki: "Heavy
Particle Emissions in Reactions between 20Ne + sOCr(ll)", 36th Ann. Meeting of the
Phys. Soc. Japan, Hiroshima, Apr. (1981).
K. leki, M. Ishihara, T. Nomura , S. Kohmoto, H. Utsunomiya , and T. Sugitate: "Light
Particle Emission in Heavy-Ion Reaction", 36th Ann. Meeting of the Phys. Soc. Japan,
Hiroshima, Apr. (1981).
T. Nomura: "Preequilibrium Phenomena in Heavy-Ion Reactions", Symp. on Nucleus-

10)

Nucleus Collision and Cluster Structure, Kyoto, Aug. (1981) .
Y. Nagame, 1. Kohno, H. Nakahara, M. Yanokura, H. Kudo, K. Sueki, and M. Takahashi:"Heavy Particle Emissions in Reactions between 20Ne and sOCr, s4Cr(lII)" , 1981 Fall

11)

Meeting of the Phys. Soc. Japan, Matsue, Oct. (1981).
S. Yamaji, A. Iwamoto, K. Harada, and S. Yoshida: "Mass Diffusion Coefficients in
the Adiabatic Approximation", 1981 Fall Meeting of the Phys . Soc. Japan, Matsue,

12)Oct. (1981).
H. Muramatsu , T. Miura, H. Nakahara, M. Fujioka, E. Tanaka, Y. Arai, and A.
Hashizume: "Conversion Electron Measurements of 119Sb Implanted Samples", 1981

13)

Fall Meeting of the Phys. Soc. Japan, Matsue , Oct. (1981).
T. Inamura and M. Wakai: "Calculation of Gamma-Ray Multiplicity Moments

223

Associated with Massive Transfer Reactions", 1981 Fall Meeting of the Phys. Soc.
Japan, Matsue, Oct. (1981).
14)

15)
16)
17)

M. Sasagase, Y. Gono, T. Kubo, Y. Itoh, S. Hayashibe, and M. Sugawara: "Search forthe a-Particle Emission from High Spin Yrast Region", 1981 Fall Meeting of the Phys.
Soc. Japan, Matsue, Oct. (1981).
M. Sasagase, H. Kumagai, M. Odera, T. Wada, and T. Inamura: "Data Processing System
at RILAC", 1981 Fall Meeting of the Phys. Soc. Japan, Matsue, Oct. (1981).
K. Ieki, M. Ishihara, T. Inamura, and S. Kohmoto: "Light Particle Emission in HeavyIon Reaction 2", 1981 Fall Meeting of the Phys. Soc. Japan, Matsue, Oct. (1981).
A. Ichimura and M. Ichimura: "Extended Brink Model and its Derivation from Distorted
Wave Born Approximation", 1981 Fall Meeting of the Phys. Soc. Japan, Matsue, Oct.
(1981).

18)

3.

H. Muramatsu, T. Miura, H. Nakahara, M. Fujioka, E. Tanaka, Y. Arai, and A.
Hashizume: "Chemical Effect on Outer-Shell Internal Conversion in 119Sn", 25th Symp.

19)

on Radiochemistry, Tsukuba, Oct. (1981).
Y. Nagame, H. Kudo, K. Sueki, M. Takahashi, H. Nakahara, I. Kohno, and M.
Yanokura: "Heavy-Ion Reactions between 20Ne and sOCr, S4Cr", 25th Symp. on

20)

Radiochemistry, Tsukuba, Oct. (1981).
K. Sueki, Y. Nagame, M. Takahashi, H. Nakahara, and I. Kohno: "Heavy-Ion Reaction
between 14N and 62 Ni", 25th Symp. on Radiochemistry, Tsukuba, Oct. (1981).

Atomic and solid-state physics
1) T. Nomura: "Fast Light-Particle Emission and Its Polarization", Proc. of Joint Meetingon Atomic Collision and Heavy-Ion Nuclear Reactions, Wako, Feb. (1981).
2) Y. Awaya: "On the Multiple Inner-Shell Ionization", Proc. of Joint Meeting on
Atomic Collisions and Heavy-Ion Nuclear Reactions, Wako, Mar. (1981).
3) E. Yagi, H. Bossy, K.P. Doring, M. G1adisch, D. Herlach, H. Matsui, H. Orth, G. zu
Putlitz, A. Seeger, and 1. Vetter: "Diffusion of Positive Muons in a-Iron", Ann. Meetingof the Phys. Soc. Japan, Hiroshima, Mar. (1981).
4) A. Yagishita and T. Nakamura: "Design of Auger-Electron Spectrometer", Ann. Meeting
5)

6)
7)

8)

of the Phys. Soc. Japan, Hiroshima, Mar. (1981).
A. Hitachi, H. Kumagai, and Y. Awaya: "A X-ray Crystal Spectrometer by Adopting a
Position Sensitive Proportional Counter", Symp. of Position-Sensitive Radiation
Detectors and Their Applications, Wako, Mar. (1981).
A. Hitachi, H. Kumagai, T. Katou, and Y. Awaya: "A Broad Range X-ray Crystal
Spectrometer", Ann. Meeting of the Phys. Soc. Japan, Hiroshima, Apr. (1981).
A. Yagishita, H. Suzuki, S. Ohtani, and H. Hanashiro: The Kr M2, 3M4SN23 and Ar
Ll L 23 M23 Coster-Kronig Processes Following Electron Impact Ionization", XII Intern.
Conf. on the Physics of Electronic and Atomic Collisions, Gatlinburg, July (1981).
Y. Awaya, A. Hitachi, H. Kumagai, T. Tonuma, T. Kambara, M. Kase, and A.
Yagishita~ "A Broad Range Crystal Spectrometer and X-rays Following Multiple InnerShell Ionizations", XII Intern. Conf. on the Physics of Electronic and Atomic
Collisions, Gatlinburg, July (1981).

224

9)

10)

11)

12)

13)

14)
15)
16)
17)
18)

19)
20)

21)

22)
23)
24)

25)

M. Uda, K. Maeda, Y. Sasa, and A. Koyama: "Chemical Effect on X-ray Spectra
Produced by 2.4 MeV He++", XII Intern. Conf. on the Physics of Electronic andAtomic Collisions, Gatlinburg, July (1981).
N. Shiotani, H. Narumi, H. Arai, K. Wakatsuki, Y. Sasa, and T. Mizoguchi:"Crystallization Processes of Amorphous Mg-Zn Alloys", 4th Intern. Conf. on Rapidly
Quenched Metals, Sendai, Aug. (1981).
N. Shiotani, S. Tanigawa, H. Iriyama, and T. Mizoguchi: "Crystallization of Amorphous
Mg 70 Zn 30 Studied by Positron Annihilation", Intern. Conf. on Amorphous System
Investigated by Nuclear Methods, Balatonfured, Sept. (1981).
A. Hitachi, H. Kumagai, Y. Awaya, M. Kase, T. Kambara, T. Tonuma, and A.
Yagishita: "The Measurement of X-rays Following Inner-Shell Ionizations by using a
Broad Range Crystal Spectrometer", Fall Meeting of the Phys. Soc. Japan, Niigata, Oct.
(1981).
A. Yagishita, H. Suzuki, S. Ohtani, and H. Hanashiro: "Read Effects on Kr MMN
Coster- Kronig Processes Following Electron Impact Ionization", Fall Meeting of the
Phys. Soc. Japan, Niigata, Oct. (1981).
A. Yagishita: "Ionization Cross Sections of Kr 3p- and 3d-subshells by Electron
Impact", Fall Meeting of the Phys. Soc. Japan, Niigata, Oct. (1981).
K. Maeda, Y. Sasa, K. Fuwa, and M. Uda: "Chemical Effect on 0 Kcx Spectra Induced
by He Ions", Ann. Meeting of the Phys. Soc. Japan, Niigata, Oct. (1981).
M. Uda, K. Maeda, Y. Sasa, and A. Koyama: "Chemical Effect on Multiply Ionized
X-ray Spectra", Ann. Meeting of the Phys. Soc. Japan, Niigata, Oct. (1981).
K. Fuwa, K. Fujima, and M. Uda: "Intensity Analysis of F Kcx Satellites for Fluorine
Compounds", Ann. Meeting of the Phys. Soc. Japan, Niigata, Oct. (1981).
M. Iwaki, O. Yoshio, T. Matsuda, K. Takahashi, and K. Yoshida: "Ion Implantation
through Aluminum Deposited Iron Plates", 42th Fall Meeting of the Japan Soc. Appl.
Phys., Fukui, Oct. (1981).
S. Sato, M. Iwaki, H. Sakairi, and I. Akiyama: "Ion Implantation in Diamond (I)", 42th
Fall Meeting of the Japan Soc. Appl. Phys., Fukui, Oct. (1981).
K. Hirose, N. Yokoyama, N. Imajo, I. Odomari, K. Fuwa, and M. Uda: "Electronic
Structures of Pd 2 Si and PtSi Observed with ESCA", 42th Fall Meeting of the Japan
Soc. Appl. Phys., Fukui, Oct. (1981).
T. Takahashi, Y. Awaya, T. Tonuma, H. Kumagai, K. Izumo, A. Hitachi, and A.
Hashizume: "Energy Straggling of 5 - 7 MeV /amu C and He Ions", 42th Fall Meetingof the Japan Soc. Appl. Phys., Fukui, Oct. (1981).
Y. Awaya: "X-ray Spectroscopy and Ion-Induced X-rays", Symp. of Atomic
Spectroscopy and Atomic Structure, Wako, Oct. (1981).
T. Takahashi: "Straggling of Heavy Ions", Symp. of Ion Beam Analysis, Wako, Oct.
(1981).
N. Yamamoto, H. Shiraishi, H. Yoshida, H. Kamitsubo, I. Kohno, and T. Shikata:"Creep Properties in Helium Injected SUS 316 and ," Precipitation Strengthened
Alloy", 1981 Autumn Meeting of the Japan Institute of Metals, Kyoto, Nov. (1981).
H. Sakairi, E. Yagi, A. Koyama, and R.R. Hasiguti: "The Damage Function Based on

225

26)

4.

the Focusing Collision Model", Intern. Conf. (Yamada Conf. V) on Point Defects andDefect Interactions in Metals, Kyoto, Nov. (1981).
Y. Awaya: "Studies of Atomic Physics by Using Accelerators of Riken", Symp. ofStudies by Using Accelerators, Wako, Dec. (1981).

Radiochemistry, radiation chemistry and radiation biology
1) S. Ambe and F. Ambe: "Mossbauer Emission Study of Defect 119Sn Atoms in
a-Irradiated SnSe", 43th National Meeting of the Chern. Soc. Japan, Tokyo, Apr.
(1981).
2) T. Nozaki: "Charged Particle Activation Analysis" , Japan-Taiwan Cojoint Meeting on
3)

4)

5)

6)
7)

8)

the Use of Small Accelerators, Taipei, May (1981) .
T. Nozaki: "Chemical Separation of 18F as KBF 4 in Oxygen Analysis by the
160eHe, p) 18 F Reaction", Intern. Symp. Modern Trends in Activation Analysis,
Toronto, June (1981).
Y. Itoh and T. Nozaki: "Depth Profiling of Oxygen by Activation with the
16 0 eHe, p ) 18 F Reaction", Intern. Symp. Modern Trends in Activation Analysis,
Toronto, June (1981).
H. Emori, M. Umehara, M. Takeya, K. Nomura, Y. Terai, and T. Nozaki:"Determination of Oxygen in by 3He Activation Analysis" , 1981 Intern. Symp. on
Gallium Arsenide and Related Compounds, Oiso, Sept. (1981).
S. Ambe, F. Ambe, and T. Okada: "Adsorption Kinetics of Carrier-free 119Sb(V) onto
a-Fe 2 0 3 ", 25th Symp. on Radiochem., Tsukuba, Oct. (1981).
T. Masui, S. Muraoka, and T. Nozaki: "Determination of IR Absorption Coefficientof Nitrogen in Silicon by Charged Particle Activation", 25th Symp . on Radiochem.,
Tsukuba, Oct. (1981).
Y. Itoh and T. Nozaki: "Heat Treatment Behavior of Oxygen in Silicon as Measured by
Charged Particle Activation Analysis", l60th Fall Meeting of the Electrochem.
Soc., Denver, Oct. (1981).

226

VIT.

LIST OF OUTSIDE USERS AND THEIR THEMES(Jan. - Dec. 1981)
1)

M. Watanabe and T. Usami

Toshiba R&D Center"Radiochemical Analysis of Band 14N in
Si Crystal"
2)

T. AbeShinetsu Semiconductor Co., Ltd.

"Radiochemical Analysis of C and 16 0 in
Si Crystal"3)

H. Emori

Mitsubishi Metal Co., Ltd.

"Radiochemical Analysis of 16 0 in GaAs"

4)

5)

H. Nakahara and M. Takahashi

Faculty of Science, Tokyo"Production of 59Co"

Metropolitan Univ.

K. Yuita

National Inst. of Agricultural Sciences"Production of 77Br"

6)

Y. Homma

Kyoritsu College of Pharmacy"Production of 87 m y"
7)

Y. Higashiguchi

Research Inst. for Iron, Steel and Other"Development of Ferritic Stainless Steel

Metals, Tohoku Univ.

for Reactor"
8)

K. Fukai and T . Furuta

Japan Atomic Energy Research Inst.

"Helium Implantation Effect on Creep
Repture Properties of Modified 316
Stainless Steel for Reactor Material
9)T. Matsutani

Electronic Parts Div. ,"Study of Effect by Bombarding HighSharp Co., Ltd.

Energy Proton on a Solar Cell"

227

10)

S. Yoshida

LSI Research and Development Lab.,"Study of Effect by Bombarding High Energy

Mitsubishi Electric Co., Ltd.

Proton on a Solar Cell"
11)

T. Fukushima

Kamakura Factory,"Study of Effect by Bombarding High Energy

Mitsubishi Electric Co., Ltd.

Proton on I.C. and Transistor"
12)

M. Hiranuma"Photograph of Cyclotron Beam"

Nomura Research Inst.

228

VIll.

LIST OF SEMINARS(Jan. - Dec. 1981)
1)

S. Yoshida, Tohoku Univ. (Sendai), 13 January"Nuclear Reactions to Continuum Final States"

2)

H. Ikegami, RCNP (Osaka), 24 January"High Resolution Momentum - Mass Analyzer"

3)

K. Shima, Tsukuba Univ. (Tsukuba), 17 February"Charge Changing of Energetic Heavy Ions"

4)

N. Onishi, Univ. of Tokyo (Tokyo), 24 February"Wobbling Mode in High Spin States"

5)

J. Grosset, Saclay (France), 3 March"Time-Projection Counter for H.I. Reactions"

6)

A. Policarpo, Univ. of Coimbra (Portugal), 9 March"Photo-Ionization and Proportional Scintillation in Nuclear Radiation Detection"

7)

T. Doke and T. Hayashi, Waseda Univ. (Tokyo), 9 March"Isotope Identification by CR-39 Plastic Track Detectors"

8)

1. Suzuki, Agency of Industrial Science and Technology (Tsukuba), 10 March"Spectroscopy of (e, 2e) in Atomic and Molecular Physics"
9)

F. Kikuchi, Univ. of Tokyo (Tokyo), 13 March"On the Problems of the Finite Element Method"10)

K. Otsuka, JAERI (Tokai), 24 March"Particle Emissions from the Preequilibrium States in the Heavy Ion Reactions and Recent
Topics on the Application of IBM to Rotational Nuclei"

11)

N. Takahashi , Texas A & M Univ. (USA), 8 April"Massive Transfer Reactions on Light Targets on Their Relation to Molecular Resonances"

12)

T. Watanabe, Univ. of Tokyo (Tokyo), 21 April"Theory of Ion-Atom Collision"

13)

R.D. Levine, The Hebrew Univ. Jerusalem (Israel), 28 April"Surprisal Analysis: A Constrained Phase - Space Approach to Heavy Ion Collisions"

229

14)

K. Sato, INS (Tokyo), 13 May"RF System (MOPA) of the INS SF-Cyclotron"

15)

H. Ohnuma, Tokyo Institute of Technology (Tokyo), 10 June
"Excitations to GT -States by (p, n) Reactions"

16)

F. Soga, INS (Tokyo), 17 June
"Near-Threshold Pion Production from Nuclei by Proton Bombardment"

17)

D.A. Swenson, LASL (USA), 24 June
"RFQ Linacs for Light- and Heavy-Ion Acceleration"

18)

N. Takigawa, Tohoku Univ. (Sendai), 27 July
"Charge Equilibration in Deep Inelastic Heavy Ion Collision"

19)

S. Honma, INS (Tokyo), 26 August"Deuteron Emission from Reactions Induced by High Energy ')'-Rays"

20)

S. Ohtani, Nagoya Univ. (Nagoya), 8 September"EBIS Ion Source and Atomic Collision Experiment using the Ion Source at Institute of
Plasma Physics"

21)

H. Hamagaki, INS (Tokyo), 9 September"Present Status of the Experiment using HISS"

22)

T. Fujita, Nihon Univ. (Tokyo), 13 October"Projectile Fragmentation in High Energy Nucleus - Nucleus Collision"

23)

D. Diamond, LBL (USA), 23 October"Spectroscopy on High-Spin States with Continuum and Discrete ')'-Rays"

24)

I. Hamamoto, Nordita (Denmark), 26 October"Rotation Properties of High-Spin States in Deformed Nuclei"
25)

A. Iwamoto, JAERI (Tokai), 20 November"Energy Spectra of ~-Particles Emitted in the Preequilibrium Process"26)

I. Tanihara, INS (Tokyo), 25 November"Two-Particle Correlations in High Energy Heavy Ion Collisions"
27)

S. Ban, KEK (Tsukuba), 3 December"On the Neutron Shielding"

230

IX.

LIST OF PERSONNEL

Members of the Board
HAMADA Tatsuji ~ EEl :@ E3
IMAMURA Masashi A-, M
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KOHNO Isao iUI !TNOZAKI Tadashi !T dffij1£ (Chairman)
SAKAIRI Hideo jJj A ~ m
SHIMA Makoto ~~HASHIZUME Akira ~ m
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KAMITSUBO Hiromichi I
ii¥ 7.i.
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MORI Kazuo ~ODERA Masatoshi IJ\ ~ 1£ f!;f~SEKIZAWA Hisashi I*l iR
UDA Masayuki ¥ EEl £t ~;@Cyclotron Operation and Maintenance Group
FUJITA Shin Wi EEl
KAGEYAMA Tadashi
KOHNO Isao iOJ !TTAKEBE Hideki lit

IKEGAMI Kumio iili 1:-. 11 .=.1=)3
KOHARA Shigeo ,j, Dit m
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KASE Masayuki 110 i*1i l§ ~MIY AZAWAY oshitoshi g iR it
YANOKURA Minoru 1fi:.!T ~~~GONO Yasuyuki ~~ e ~IKEZA WA Eiji iili iR !Jf:
KAMBARA Tadashi t$ &i
KUBO Toshiyuki 7-... 1* ~TONUMA Tadao
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Scientific and Engineering Personnel

Cyclotron Laboratory
FUJISA WA Takashi WM iR ~ ~.;GOTO Akira ~ iIi~;
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INAMURA Takashi fffi t>.t.$.
KAMITSUBO Hiromichi I
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NAKAJIMA Shunji cP m ~, NOMURA Toru !f M
7SHIKAT A Takashi ~ 15 I~ 5:
YAMAJI Shuhei
UJ ~~ {~ ~=;@FUJITA liro Jii EEl&~
HARA Masahiro mI~"51.
IKEGAMI Yuji iili -.t f:tj 5]
ISHIHARA Masayasu :tr mt 1£ ~KARAS AWA Takashi @= iR
4KOHMOTO Susumu iOJ~
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YAN 0 Yasushige Ifo:. !T 'IX. ~

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HA YAKA WA Shunichiro !f! J II {!;f - &~ (Dept. Phys., Waseda Univ.)
HIRUTA Kotaro ft EEl :$* &~ (Dept. Phys., Tokyo Gakugei Univ.)
ICHIMURA Munetake $ M
lEt (lnst. Phys., College General Education, Univ. ofTokyo)*

231

NAKAHARA Hiromichi cP Jjji 51. :@: (Dept . Chern. , Tokyo Metropolitan Univ.)
SATO Kenichi 1ti: 1fi ~ - (Dept. Phys., Tohoku College of Pharmacy)
SHIRAISHI Haruki B E ~ W (Nat . Res. Inst. for Metals)
TAKEMASA Tadashi fFt iJ& J3" ± (Dept. Phys., Saga Univ.)§f. (Dept . Phys. , Tohoku Univ.)
TAKIGAWA Noboru ~ JII
YOSHIDA Shiro 6" EB }~'- a~ (Dept. Phys. , Tohoku Univ.)
UTSUNOMIYA Hiroaki ~ t~ g 51.
(lnst. Nucl. Phys. , Univ. of Tokyo)*(Students)
BAN Mitsuo 1*
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HOSOYAMA Michio *fB UI = -=f~ (Facul. Sci. and Eng. , Chuo Univ.)
IEKI Kazuo
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MASHIY AMA Tsuguo t~ UJ ?!x -!J3 (College of Hum . and Sci., Nihon Univ.)
NAGAME Yuichiro 7k El ~ - a~ (Dept. Chern. , Tokyo Metropolitan Univ.)
OBANA Yoshiki IJ\ TE 7i(Dept. Phys. , Chiba Univ.)
SUGITATE Toru ;f~ 1L
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TANAKA Yasushi EB cP 1* , ~ (Facul. Sci. and Eng. , Chuo Univ.)
TOY AMA Akifumi:7t UJ Btl )( (College of Hum. and Sci. , Nihon Univ.)
WATANABE Mitsuyuki iN. ill~ (College of Hum. and Sci. , Nihon Univ.)

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KUBO Toshiyuki ~ 1* ~ ~ODERA Masatoshi
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EJIRI Hiroyasu iI JfL 7i. ~ (Dept. Phys. , Osaka Univ.)
FUKUZAWA Fumiof~/R )( a (Dept. Nucl. Eng. , Kyoto Univ.)
HARADA Kichinosuke Jjji EB ~ z M (Japan Atomic Energy Res. Inst.)$
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HAYASHIBE Shogo~ tEl:: fO :;t;:. (Tokyo Inst. Technol.)
HISATAKE Kazuo
ISHII Keishi E ft- ~ Z (Dept. Nucl. Eng., Kyoto Univ.)
ITO Noriaki fft 1fi J!J BB (Dept. Crystalline Materials , Nagoya Univ.)
KAWAI Nanao 1iiJ ~ -t a (Osaka Univ.)(Tsukuba Univ.)
MASUDA Kozo :fI- EE 0.
MATSUI Masao f~ ft- 1E :;t;:. (Nagaoka Sci. and Tech. Univ.)
MORITA Susun1u ~ EE
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OZAWA Kunio IJ\ /R I~ :;t;:. (Japan Atomic Energy Res. Inst.)
SAKISAKA Masakatsu IPJ :t)X if 1m (Dept. Nucl. Eng. , Kyoto Univ.)
TAKEDA Shigeru it EE~ (Nat. Lab. High Energy Phys.)

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YOKOYAMA NatsukizRadiochemistry Laboratory
AMBE Shizuko '!i!: M) fIt =rITO Y oshiko {:=Jjjj
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