the Institute of Physical and Chemical Research
Wako-shi, Saitama Pref., JAPANIPCR cyclotron
Progress Report 1980

Vol. 14

IPCR Cyclotron Progress Report
Vol.14The Institute of Physical and Chemical Research"RIKAGAKU KENKYUSHO" Wako-shi, Saitama,
December, 1980

351 JAPAN

Editors
F. AmbeY. GonoA. Hashizume

Y. Hattori

H. Kamitsubo

T. Nomura

M. Odera

M. UdaT. WadaThis volume contains recent information of the IPCR Cyclotron, informal reports andabstracts 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.

CONTENTS
Page

1.

INTRODUCTION

2.

MACHINE OPERATION

3.

MACHINE DEVELOPMENT AND ACCELERATOR PHYSICS

4.

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

2

3-1.

Improved Heavy Ion Source for the Cyclotron . . . . . . . . . . . . . . . . . . . . . . . .

4

3-2.

Automatic Frequency Controller of the Cyclotron

6

3-3.

Electromotive Slit in the Beam Transport System of the Cyclotron . . . . . . .

9

3-4.

Present Status of the Baby Cyclotron at the Nakano Hospital

11

NUCLEAR PHYSICS
Scattering and Reactions

4-1.

Analyzing Power-Polarization Inequality in the Inelastic Scattering ofProtons on 12 C at Incident Energies from 22.0 to 29.0 MeV . . . . . . . . . . . . . .

13

4-2.

Final State Interaction in Heavy Ion Reactions

16

4-3.

Study of a-Particle Emission in 14 N + 159 Tb Collision I

19

4- 4.

Study of a-Particle Emission in 14 N + 159 Tb Collision II

22

a Emission in the 209 Bi + 14 N Reaction at 115 MeV

Angular Momentum Transfer and Alignment Following Preequilibrium....................

25

93

Polarization of Preequilibrium Proton Emission in the
Nb + 14 N Reaction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

28

4-7.

Spin Alignment in Heavy Ion Reaction

31

4-8.

Reactions between 20 Ne and 5°Cr

34

4-9.

Recoil Range Distributions in the Reaction Induced by 115 MeV 14 N
on 62 Ni . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

37

4-10. Correlation between the Fragment Mass and the Angular Anisotropy
in the Proton-Induced Fission of 232 Th . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

40

4-11. Friction Tensors for Ar + Au and Cu + Au..........................

44

4-12. Numerical Analysis of the 63 Cu + 197 Au Reaction Based on the Linear
Response Theory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

47

4-5.

4-6.

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

Page

5.

6.

4-13. Semiclassical Treatment of the Direct Reactions Induced by
Heavy Ions II. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

50

4-14. Proton Inelastic Scattering to the (1 +, T= 1; 15.1 MeV)
State in 12 c·. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

53

4- 15. Perturbation Theory of Mass Transport in Nuclear Collision

56

NUCLEAR PHYSICS
Nuclear Spectroscopy and Instrumentation
5- l.

High Spin States in 158 Yb . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

59

5- 2.

Calculation of Widths of Hole Analog States..........................

61

5- 3.

A Double Scattering Proton Polarimeter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

64

ATOMIC AND SOLID-STATE PHYSICS

6- 1.

X-Rays Following Multiple Inner-Shell Ionization (5). . . . . . . . . . . . . . . . . . .

67

6-2 .

A Target Chamber for X-Ray-Angular-Di stribution Measurement . . . . . . . . . . .

70

6- 3.

Kr KJ3/Ka X-Ray Intensity Ratio by 6 MeV/amu Ion Bombardment . . . . . . . .

72

6- 4.

Chemical Effect in Cu L X-Ray Satellite Spectra . . . . . . . . . . . . . . . . . . . . . .

74

6- 5.

Energy Straggling of C Ions in Metal Foils and Foil
Non-Uniformity Effect

77

6- 6.

Helium Embrittlement in Precipitation-harde nable Alloys . . . . . . . . . . . . . . . .

79

6- 7.

Backward Secondary Electron Emission from Al, Cu, Ag, and Au
Targets under High Energy N 7 + and N 4 + Ion Bombardments . . . . . . . . . . . . . .

82

Measurements of the Compton Profile and Angular Correlation of
Positron Annihilation Radiations in Amorphous Mg 70 Zn 30

84

Sn Emission Mossbauer Study of 119 Sb Adsorbed on a-Fe 2 0 3

86

6- 8.

6- 9.

119

. . . . . . . . . . .

6-10. X-Rays Induced by Collisions between 110 MeV Ne Ions and Gases ..
7.

88

RADIOCHEMISTR Y AND NUCLEAR CHEMISTRY

7- 1.

Chemical Separation of 18 F in the 3 He Activation Analysis of Oxygen7- 2.

Recoil Range of 18 F Formed by Various Reactions

91. . . . . . . . . . . . . . . . . . . . . 93

Page

7- 3.

7-4.

7- 5.

8.

9.

10.

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

94

Isomer Shift of 119 Sn in Binary Compounds of the Elements from
Indium to Iodine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

96

A Mossbauer Emission Study of Defect 119 Sn Atoms
in Proton- and a-Irradiated SnSe . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

98

RADIATION CHEMISTRY AND RADIATION BIOLOGY
8--1.

Inactivation of Ribonuclease A in Solution by N- Ion Beam

101

8-2.

Inactivation of Cultured Normal Human Fibroblasts, IMR-90,
Cells with Nitrogen Ions Accelerated in the Cyclotron

102

RADIATION MONITORING
104

9-1.

Routine Monitoring

9-2.

Leakage-Radiation Measurement at the Underground Passage . . . . . . . . . . . . 106

HEAVY ION LINEAR ACCELERATOR PROJECT
10- 1.

Status of RILAC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108

10- 2.

Control System

10- 3.

Design of ECR Ion Source . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113

10- 4.

System for Beam Monitoring with Beam Slit and Stopper

115

10-5.

Acceleration Test of the First Cavity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

117

10-6.

Design of RF Control System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120

10-7.

Measurement for Characteristics of RILAC RF System andExcitation Test of Resonators

110

123

10-8.

Magnets for Beam Transport System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126

10-9.

Vacuum System of the Beam Transport Lines . . . . . . . . . . . . . . . . . . . . . . . .

10-1 0.

Heavy Ion Source for the Linac . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 2

10- 11.

Power Supply for Heavy Ion Source . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

129

135

Page

11.

10-12.

Multi-Wire Beam Emittance Monitor and Beam Profile Monitor

138

10-13.

A 100 em Scattering Chamber

141

10-14.

Design of an Electron Spectrometer

10-15.

Electron Energy Analyzer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 146

10- 16.

Design of an Apparatus for RILAC-Beam Irradiation of
Biological Samples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 148

10- 17.

Beam-Foil Spectroscopy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

10-18.

Multichannel Detection in Normal-Incidence Vacuum
Ultraviolet Region . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151

10-19.

Spherical Target Chamber for Heavy-Ion Implantation

10-20.

On-line Data Processing System at RILAC . . . . . . . . . . . . . . . . . . . . . . . . . . 156

10-21.

Beam Sharing System between Linac and Separated-Sector
Cyclotron . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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

143

149

154

159

SEPARATED-SECTOR CYCLOTRON PROJECT

11 - 1.

Status of the Separated-Sector Cyclotron in IPCR (Riken)

11 - 2.

Design of the Sector Magnet for the SSC . . . . . . . . . . . . . . . . . . . . . . . . . . . . 164

11 - 3.

Design Study of the Canted Injection Scheme for the IPCR
sse (I) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 167
Design Study of the Canted Injection Scheme for the IPCR
sse (II) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 170

11 - 4.

11-5.

162

Model Study of the Injection Bending Magnet of the IPCR

sse . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 173
11-6.

Magnetic Field Measuring System for the Model Injection-Bending
Magnet of the SSC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 176

11-7.

Microcomputer System with CAMAC for Measuring Magnetic Field ofa SSC Model Magnet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

179

11-8.

Design Study of RF Resonator for the SSC

182

11-9.

Design Study of Oscillator for the SSC

185

Page

11-10.

Measurement of RF Field Distribution for a Quarter
Wave-Length Vertical Type Resonator . . . . . . . . . . . . . . . . . . . . . . . . . . . .

187

11-11.

Some Properties of Accelerated-Beam Orbit in the
Separated-Sector Cyclotron. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 189

11-12.

Design of Beam Transport System for the IPCR SSC

11 - 13.

Vacuum System of the SSC (I)Vacuum Considerations in Some Aspects

192. . . . . . . . . . . . . . . . . . . . . . . 195

11-14.

Vacuum System of the SSC (II)A Preliminary Design of the Vacuum Chamber for the SSC . . . . . . . . . . . 198

11-15.

Design and Operational Performance of Superconducting Coilfor Model Sector Magnet of the IPCR SSC . . . . . . . . . . . . . . . . . . . . . . . . . . 20 1

11-16.

Present Status of Radiation Shielding for the Riken SSC Facility. . . . . . . . 203

12.

LIST OF PUBLICATIONS .............................................. 207

13.

LIST OF OUTSIDE USERS AND THEIR THEMES

14.

LIST OF SEMINARS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 216

15.

LIST OF PERSONNEL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 218

214

AUTHOR INDEX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 223

1.

INTRODUCTION

It has passed fifteen years since we had the first beam from IPCR 160 em cyclotron andexperimental studies were started. This cyclotron was the first one in Japan which was used forthe studies of diverse research fields.

These studies have been performed mainly by using heavy

ions.
During the past one year, the cyclotron was operated in good condition as before. New
developed heavy ion source was tested. An automatic RF frequency controle system wasinstalled and made the stable operation of the cyclotron possible.
A majority of research works have been carried out with heavy ions. In the field of nuclear
physics, polarization of the outgoing protons from heavy ion collision was measured to get moredetailed information of the reaction mechanism.

Final state interaction was studied by measuringcorrelation of two a-particles in the heavy ion reaction. Extensive studies on theoretical analysisof the heavy ion reaction based on the linear response theory was performed in collaboration
with JAERI.
X-rays following the inner shell ionization were also extensively studied. Backward secondary
electron emission from metallic substances were measured by born barding heavy ions on them.
Study of radiation damage in a-particle bombardment was continued.
Charged particle activation analysis of oxygen contamination was applied to study the behaviorof the oxygen on the surface of the pure silicone materials. Study of the radiation chemistry andbiology was continued as before.
Construction of the heavy ion linac (Rilac) was finished last year and the beam test has been
continued. Construction of the energy booster of Rilac was started in this period. Final designof the separated-sector cyclotron is now underway.

Hiromichi Kamitsubo
Editor2

2. MACHINE OPERATION

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

The cyclotron was operated on the 24 h a day basis during the period from Oct. 23, 1979 toOct. 22, 1980. The total operation time of 4355.6 his 4% (179.7 h) shorter than that of thelast year. This decrease in operation time is due to some scheduled shut-down shown in Table 1,
and is caused by a rise in price of electric power.
Table 2 shows the beam time alloted to various activities in this period. Although the total
beam time (54 78 h) was decreased by 242 h compared with that of last year, requirement forheavy ion beams continued to increase; its increase was 269 h.
Table 3 shows the distribution of the beam time among particles accelerated. In this period,
the beam time of highly charged ions such as N5 + and Ne 6 + was greatly increased. The metal
ions as 7 Li 2 + and 11 B3 + were newly accelerated using the sputtering metal ion source 1) in thisbeam time.
In order to improve the performance of the heavy ion source and to shorten the time forsetting up of the source, a new improved heavy ion source was developed and tested during thetime of the overhaul and the periodical inspection. Furthermore, the frequency stabilizer forthe radiofrequency system of the cyclotron and the slit system of the beam transport adjusted
by remote control were newly installed in this period. These improvements served to makegood use of the beam time.
Table 1.

Machine Operation.

Oscillator

Ion-source

BeamReading of time meteron Oct. 23, 1979

61899.6 (h)65865.6 (h)32873.1 (h)Reading of time meteron Oct. 22, 1980

66807.1

70893.837228.7

Difference

4907.55028.24355.6

56 %

57 %

50 %

Percentage of 365 days
Schedule in this period
Beam time

233 (days)

Overhaul and installation work
Periodical inspection and repair

59
25

Vacation and holidays

38

Other scheduled shut down

10

3

Table 2.

Scheduled beam time and subjects of activity in the period XV.

Subject{

Nucl. Phys.

Fields others
than N ucl. Phys.

Heavy ionLight particles

Total

Nuclear reaction
In-beam spectroscopy
RI production

3093 (h)
450
24

0 (h)
0
15

3093 (h)450
39

Nuclear chemistry
Radiation biology
Solid state physics

0
144
305
441

192
120
356
0

192
264
661
441

0
0
0

132
110
96

132
110
96

4457

1021

5478

Inner atomic shell
excitation study
Nuclear fuel study
RI production{ Detector
calibration

Outside users

Total

81%

Percent in total

19%

100 %

Maintenance, operation and engineering

114 (h)600 (h)Exchange of ion source
Machine inspection and repair

714

Total

Table 3.

Distribution of Beam time among particles accelerated.

Particle(h)(%)

Particle

(h)

(%)

p

228
16
142
635
402
1130

4.2
0.3
2.6
11.6
7.3
20.6

Ns+

1509
117
1257
21
21
5478

27.5
2.1
23.0
0.4
0.4
100.0

d
3 He++

4 He++
c4+
N4+

os+
20Ne6+
7 Li2+

11 B3+

Total

Reference

1)

K. Ikegami, T. Kageyama, and I. Kohno: Japan. J. Appl. Phys., _!2_, 1745 (1980).

4

3.

MACHINE DEVELOPMENT AND ACCELERATOR PHYSICS

3-1.

Improved Heavy lon Source for the Cyclotron

T. Kageyama, K. Ikegami, and I. Kohno

In order to extend the life time of the heavy ion source and shorten the time to revive it
we developed an improved heavy ion source for the cyclotron.
Figures 1 and 2 show a cross-sectional view and a photograph of this improved source. Thision source is supported by a single supporting tube (T), while the old type source was supported
by two tubes. 1 )The head part of the improved source can be removed from the supportingstem at a position indicated by A in Fig. 1.
When the life time of the source is over, the head part is taken away and new one is
attached in several minutes. Furthermore, this source is improved from the old one in exactnessof alignment of the geometrical center of anode chimney and two cathodes (K 1 , K 2 ). By thisvE"""'~"""==-----1;>''7j"-

B
HSH

CMI

K 1 : hot cathode (W or Ta)
K 2 : reflector (W)F: filament (W)SH: electron shield (Mo)
CM 1 , CM 2 : cathode mount (copper,

cooling channel joint
11 , 12 , 13 : insulator (ceramic)
D: distribution plenum

water-cooled)
HSH: cathode heat shield (W)T : suporting tube (stainless steel)
B: anode box (copper)

SP: slit plate (Mo)

HA: hot anode (copper)

Fig. 1.

J1 , J2 :S: source aperture
L: leading tube

Cross-sectional view of the source.

5

Fig. 2.

A photograph of the ion source.

<(

::t

c: 5.0
~

:::J

u

c

_s
:!:
z

A typical variation of beam
intensity with radius in the cyclotron
for 95 MeV N4+ ion.

Fig. 3.

Radius( mm )

improvement the life time of the source was extended to about twice of the old one.
4
4
5
Using this improved source several kinds of ions (Ne 6+, N +, N +, and c +) have been
produced and accelerated in the cyclotron. Figure 3 shows a typical radial variation of beam
4
intensity in the cyclotron for 95 MeV N + ions. As is shown in this figure, the intensity ratioof the external beam to the internal beam is poor (about 1/5) and this reason is being studied.
In Table I the results of accelerating test of serveral ions are summarized. At present, thissource is used to accelerate Ne 6+ ions.
Table 1.

Particles, energy ranges and particle yields.

Particle

Energy (MeV)

Extracted beam current

20Ne6+

82-1600.2J.LA*c4+

49-1002.0J.LAN4+

57-1002.0J.LA

Ns+

57-125l.OJ.LA* Pulsed operation.

Reference
1)

Y. Miyazawa, I. Kohno, T. Tonuma, T. Inoue, A. Shimamura, and S. Nakajima:
Cyclotron Technical Report, No. 2 ( 1972).

IPCR

6

3-2.

Automatic

Frequency Controller of the Cyclotron

H. Takebe, K. Ogiwara, an d Y. Yamada*

The RF (radio frequency) system of the cyclotron 1) has a self-excited oscillator whose frequency isdetermined by the geometrical condition of the RF resonator. The resonant frequency drifts due to themechanical deformation of the resonator occured thermally in about an hour after RF power has been switched on.
Figure 1 shows the frequency change by a thermal deformation of the resonant cavity in thirty minutes from thestarting time of the RF power. In the first 20 min, the resonant frequency decreases by about 7 kHz, the mean
decreasing rate depending on the dee voltage. The resonant frequency is changed not only by thermal
deformation of the cavity but also by positions of the beam prove , deflector , ion source and the small (west)
compensator, arc power strength of the ion source, and a discharge in the dee-earth gap . Therefore , theresonant frequency had to be adjusted by manual operation whenever any ope rating parameter was changed .
In order to avoid such a complicated procedure an automatic frequency controller has been developed andequipped to the cyclotron.
A brock diagram of this control system is shown in Fig. 2.

BCD presets (Fp) in six digits which are set

by a rotary encoder and the up-down counter are subtracted from the six digits' BCD data (Fe) of the frequency:I:

Discharges

7.780

L:

c::

2 7.778
0
u
>u

Q)

:5
0

~

Di scharges

I

l l

52kV

47 kV

7.776

50kV

~ 53kV

cc:: 7. 774

Arc on Mai n probe insert

Q)

::::J

cr

~ 7.772

ccu

0::

\}

RF Drift checkon 1980, Oct. 8
W + 95 MeV

>
cu

(f)
Q)

I

7.770

0

2

3

4 5 6
8 10
Time (min. )15

Fig. 1. Resonant frequency drifts
in the first 30 min at various deevoltage and conditions of theresonant cavity.

20

r1 Mode swi tch II
Duty ti me sel ect

N select- F'p

I6FI> JVX 0.1 kHz
Comparator 1 J~

Command

6F

processor
Comparator 2 I Stop
6F >200kHz

+Fe

/

Up

I

loow nPulse

Upper earth plate
Cyclotron
Resonat or

Lower earth pi ate
West compensator

Fig. 2.
* Work Shop of this Institute.

Block-diagram of the automatic frequency controller.

7

Table 1 (b)Table 1 (a)The command processor

The position of the .6F mode switch (N-number) is

makes up or down signal

selected in accordance with the beam course andaccording to N-number
which is determined by theparticle's energy. Sample rate of the frequency
counter is set by about 0.3 sec usually in any .6F.6F mode switch.

mode.
No.1

No.2

No.3

No.4

2

3

4

6

Samplerate (sec)0.2- 0.4

0.2 - 0.4

0.3 - 0.6

0.3 - 1.0

Duty time
(sec)

0.2

0.3

0.3

0.5

.6F >200kHz

STOP

Mode

.6F > N X 0.1 kHz

DOWN

N

1.6FI ~ N X 0.1 kHz

STOP.6F < N X 0.1 kHz

UP.6F <200kHz

STOP.6F =Fe - Fp
counter (TR5104f) of the cyclotron RF system. If the difference .6F(= Fe- Fp) is positive with the value
greater than N X 0.1 kHz (N is indicated in Table 1 (b), the up-down command processor gives a frequency
lowering signal to a device which may be the upper earth plate, the lower earth plate or the west compensatorin order to decrease the resonant frequency. These parameters of each mode are shown in Table 1. When
1.6.FI is greater than 200 kHz, the processor commands nothing but indicates the situation by "Over" lamp
because the resonator may be unusual: For instance RF discharge in the dee chamber or a parasistic oscillation
is excited (IFI > 200 kHz).
The up-down command is transfered to the AC motor drive units as pulses shown in Fig. 3. As mechanicalstructures of the movable earth plates and the west compensator have a large inertia which may cause an
over-shooting, the command signals should not be too long so that the device stops changing frequency before
the next gate time of the frequency counter begins.

The sample rate of the frequency counter and a duty

time of the command pulses can be selected by a mode-switch as shown in Table 1 (b). In accordance withthe beam line used , kind of accelerated particles and energy of particles, the mode switch should be selected by
the operator.
This automatic frequency controller is in the form of a compact box with a simple front pannel using thelatest digital electronics as shown in Fig. 4. A conventional relay units and AC motor driving relays had
been used to move the upper earth plate in the previous control system. They were exchanged with solid

F- Counter gate

UP or DCMin signal( DC5V )Command pulses( DC48V )SSR Motor power supply( AC200V )Mechanical movement

Time chart of the up or down command
pulses and movement of the resonating device.
Fig. 3.

The command pulses of the processor shoud not
be too long to avoid over-shooting.

A front pannel of the new systemequipped on the control desk.
Fig. 4.

8

state relays (SSR: D2W201B, I.O.R. Co.) with circuits for detection of zero-crossing phase of AC 200V.
The new relay system is shown in Fig. 5.
It has been found enough to use only the upper earth plate in the automatic mode of this frequency
controller to make the resonant frequency constant for any .6F mode and in any resonant frequency(6 - 12MHz) of the cyclotron. The daily operation of the cyclotron has become much easier than before
because of this device.

Up

SSR 1 (D2W20 1B : I O.R. Co.l[z
Up ccmmand

Indicate lamp
j

To
Motor

Limi tf x

sw

t---

-

.---+-t----f----1-- - l - - - + - ---

R

s
T

Down

l R

Down

Fig. 5. Solid-state relay circuit. Up
command should keep stopping anothercommand until 7 msec after the up pulse
by Tr 3 to avoid short-circuit of the AC

ccmmand( + 48V)

LimitfN

F

sw

Fuse (3 A)

200 V power line; the time interval of
the up and down signal of the power
supply should be longer than 6.67 msec

u v w

( T = 1/(3 X 50 Hz) ) because the delayin action by the zero-crossing circuit in

Input 3¢ 200V

the three phase of AC power supply.

ReferencesI)

M. Odera, Y. Chiba, T. Fujisawa, Y. Miyazawa, and 0. Terajima: The Radio frequency System of the IPCR
Variable Energy Multi-Particle Cyclotron; IPCR Technical Rep., 8 (I 973).

2)

TR51 04, Takeda Riken BCD parallel out.

9

3-3.

Electromotive Slit in the Beam Transport
System of. the Cyclotron

S. Kohara, I. Takeshita, K. Hagiwara, * and Y. Nomiya*

There are many slit boxes in the beam transport system of the cyclotron. Each slit box has
four blades moved by hand operation and a beam shutter moved by electric power remotely.
In the case of RI production the aperture and position of beams at the target are determined bypositions of four movable blades in the slit box installed at about 200 mm in front of the target.
Therefore, it is very convenient for operators and experimenters to be able to adjust the positions offour blades observing image of the aperture and position of beams on a quartz plate set at theposition of the target using an lTV. For this reason we developed a new slit box which has four
blades moved by electric power remotely.
Figure l shows a photograph of this slit box installed in the beam line for RI production.
The slit system consists of a left blade, a right blade, an upper blade and a lower blade. The
left blade can be moved from the center of the beam line to the left direction or outside direction
up to 30 mm and to the right direction or inside direction up to 10 mm. The other blades canalso be moved in a similar way. Driving speed of these blades are 0.33 mm/sec.
Figure 2 shows a photograph of the controller for the slit box. The positions of four blades
are indicated by digital numbers in the front plate and several switches for operation of blades
and a beam shutter are equipped. Safety circuits are provided to prevent the collision between theleft and the right blade, and between the upper and the lower blade, respectively. This electromotive
slit serves to make efficient use of beam time of the cyclotron.

Fig. 1.

* Work Shop of this Institute.

Photograph of the slit box.

10

....

,_,_,..,_.......,_..;;~

Fig. 2.

Photograph of the controller for the slit box.

11

Present Status of the Baby eye lotron at the

3-4.

Nakano Hos pita I

T. Karasawa, T. Nozaki, and S. Iida*

During this year, the cyclotron has been working satisfactorily for the production ofradio-isotopes used in diagnosis and in experiments of labelled compounds synthesis. The beam
currents at the target box were 10 p.A and several p.A for protons and deuterons, respectively.
The beam shape has been improved by the insertion of the magnetic channel. l )
/\
x

\

/

\

I

I
I

2. 0

\

~

\

I

\

I
I
I

\
\
\

I
I
I

\

J
J

1.0

J

I
I

X

I
I
/
//x

",x
X

'"

-10 - 5 0

5 10 15 20 25 30 35( mm )

Fig. 1.

Radial distributions of the beam at the target.

Deflection voltages were 35 kV for 0 and 34 kV for x .
5.0
4.0::2 30-....--..
0:::

E

2.0
10

10

5

15

( mm )

Fig. 2.
Vertical distribution at the target. Copper
plate was bombarded to induce 63Cu(p, n)63Zn reaction.
63 Zn activity was measured with position resolution of
2 mm. The radial distribution was affected byoperating parameters.
* Japan Steel Work Co.

Radial and12vertical beam distributions are shown in Figs. I and 2, respectively. Usually the aperture of thetarget box window is kept 5 em in width and 2 em in height.
One of the main features of the cyclotron is the self radiation shielding. 2) Radiation levels
around the cyclotron room were surveyed. 3 ) It can be estimated from the result that theradiation level is below 10 mrem/week for 40 h operation per week with 30 J.!A proton beamat all measurement points except at those nearer than 0.5 m from the wall of the cyclotron room.
A water-cooled cone of the ion source and an oil-cooled electrode of the deflector are
under preparation for higher beam intensities and more reliable operation. Those improvements
have already been applied satisfactorily to the second Baby Cyclotron.
A mixture of glucose-llC and fructose-llC has been routinely prepared by photosynthesis
and used for diagnosis of lung cancer.

A glass vessel containing spinach leaf pieces (0.5 g) and11

C0 2 prepared by the cyclotron is illuminated for 7 min, and the photosynthetic product is
extracted into hot EtOH containing HCI. The extract, after removal of ether-extractable
substances, is concentrated by partial evaporation by microwave heating, and treated with an anion
exchange columun to give a mixture of uc glucose and fructose. It takes 35 min for the total
process, and from 50 mCi of the 11 C0 2 about 10 mCi of the product is obtained. The productis orally administered to the patient and the 11 C distribution in lung is examined. This 11 C has
been found to behave differently from 197 Hg glutathione and 67 Ga compounds. About 60 patients
have ever been submitted to this diagnosis. The photosynthetic process has been partly
automatized and its complete automation is under way.
Automatic synthesizers for 11 C palmitic acid and 11 CH 3I have been set up. The distributionof 13 NH 3 in rat brain was examined by radio-autography with its time change. A few other
11 C compounds were synthesized and their behaviour in experimental animals were studied.

References
1)

T. Karasawa and T. Nozaki: IPCR Cyclotron Progr. Rep., _!1, 20 (1979).

2)

T. Karasawa: Japan patent 818015, USA patent 3921019, and France patent 2209272.
T. Karasawa, T. Tanaka, and T. Yoshida: Pro c. of the 3rd Symp. on Accelerator Science

3)and Technology, Aug., p.93 (1980).

13

4. NUCLEAR PHYSICS
Scattering and Reactions

4-1.

Analyzing Power-Polarization Inequality in the

Inelastic Scattering of Protons on

12

C at Incident

Energies from 22.0 to 29.0 MeV

T. Fujisawa, N. Kishida, T. Kubo,
T. Hasegawa,* M. Sekiguchi,* N. Ueda,*
M. Yasue,* Y. Wakuta,** and A. Nagao**

NUCLEAR REACTIONS 12 C (p, p' 'Y), 4.43 MeV state , E = 22.0 - 29.0 MeV,
polarized beam; measured cross section, asymmetry, spin flip probability,l[ spin flip asymmetry; deduced difference between asymmetry
and polarization.

A large number of studies for elastic and inelastic scatterings of protons on 12 C has been performed over theincident energy range of about 20 to 30 MeV. 1) 12

3

C contributes in this energy region or not. ) -mechanism than cross-sections.

5)It, however, is in question whether the giant resonance of

5)Spin-dependent observables are more sensitive to a reaction
Particularly it is important to measure the difference between analyzing

power (A) and polarization (P). 6 ), 7 )requires a double scattering.

Direct measurement of the polarization, however, is very difficult because it
Therefore , we measured the A, spin flip probability (SF) and spin flip asymmetry(SFA) simultaneously using polarized protons and deduced the (A-P) at incident energies from 22 to 29 MeV.
The observables for nucleon scatterings are expressed as follows if the Z-axis is chosen along the normal to
the scattering plane:

a 0 =: (a. +++ a+ _ + a - + + a _ ) / 2,A = (a++SFA = (a+ - -+ a+ -

a _+ -

a __ )l2a0,a _+ )/(a+ - + a _+) =(A - P )/(2 · SF),

where a+- is the partial differential cross section for scattering from an incoming spin-up state ( +) to a final
spin-down state ( - ). S) It is easy to see from the above equations that the measurement of spin flip probability
using a polarized beam determines individually aa{3 and so all of the observables in these equations are deduced. 8 )The measurement was carried out by using the (pp' 'Y) method, i.e., by measuring the angular correlation
between protons scattered inelastically from the first 2+ excited state and the E2 (2+ -+ 0+ ground) de-excitation)'-rays emitted perpendicularly to the scattering plane. 9 )Polarized protons were obtained from an atomic beam
type polarized ion source and were accelerated by the SF Cyclotron at the Institute for Nuclear Study ,University of Tokyo. The ion source was constructed at the Institute of Physical and Chemical Research. The
beam current on the target was about 10 nA and the beam polarization was about 50 %. The beam polarization
was reversed about every one minute by the RF transition units of the ion source which were controlled
automatically with signal from a beam current integrator to eliminate systematic errors. The 12 C target was aself-supporting foil of natural carbon with thickness of 5.65 mg/cm 2 . The )'-rays were detected with a shielded
Nai (T1) crystal of 7.6 em X 7 .6 em mounted on a 56 AVP photomultiplier.

This detector had a lead slit ofan aperture of 57 mm¢ with 10 em of thickness at position 20 em from the target. The scattered protons were
* Institute for Nuclear Study, University of Tokyo .
* * Kyushu University.

14

detected hy four pairs of solid state detectors which were set symmetrically on hoth sides of the heam direction.
A defining slit of 10 mm¢ was placed in front of each detector at a position 10 em from the target. In Fig. 1 thedata obtained are shown. It was remarkable that the SFA and the (A-P) have such large values and change
drastically with the incident energy in contrast with a rather monotonous change of the inelastic scattering crosssection. I) The effect of some resonance on the reaction must he strong since the (A-P) and SFA depend on
interferences between partial waves of which angular momentum are different . A coupled-channel calculation
with Breit-Wigner terms is inprogress.

SF (%)

•

60

••

40

•

A - P (%)

A (%)

SFA (%)

•• ••
•

: ~M
l)

60

20

20
0 L..J....._.J...._L_J.._J_....l..._.l........J•

0 L.L_L_.L---L....J.......JL....L....:f

20 t~···
0!-'-..I......JL_J.._J_...J...._L....:J.

0

40~

40

•
•••

40

0
0
0

20

°

40
oq;o

0

•

40 ~A, ~
20~

Ji

•
•

~

6~

~f

40

40

0

or:P

•
oo oo

oo

40 OOo o

Ooooo

20

0 L..J....._.l___l__l_...l..._.l........l._J

'

- 20

-.. ....
o

••••

20

•••••

•

a ~~-*~~~-40

2~Ll. .-8L.L.Lab._J.=_. .4JL.5.oL ~2~~0

· · · ·-

22 24 26 28

20r
t=
Q 0 000 00..L_jo10 •••••-20-20

BLab. = 60°

20

20~
00 c3
0
20~
0 •• • •

~

-20
40

•

0
0

0 oo

- 40

0

- 20

~2~ ~ ~2~ •••• .···:···-- ~2:
-40

- 40

- 40
22 24 26 28

•

22 24

26 28

22 24

26 28

Incident energy ( MeV ) in Lab .

Excitation curves of the spin flip probability (SF), spin flip asymmetry
12(SFA), analyzing power(A) and A-Pin the inelastic scattering of protons on C
at the lab. scattering angles of 45° , 60°, 75°, 105°, 120°, 135°, and 150°. The
Fig. 1.

line is to guide the eye.

15

References
1)

J. K. Dickens, D. A. Haner, and C. N. Waddell: Phys. Rev., 132,2159 (1963).

2)
3)

T. Tamura and T. Terasawa: Phys. Lett.,__§_, 41 (1964).
R. M. Craig, J. C. Dore, G. W. Greenlees, J. Lowe, and D. L. Watson: Nucl. Phys. , 83,493 (1966); ibid, 79,
177 (1966).

4)

H. V. Geramb, K. Amos, R. Sprickman, K. T. Knofle, M. Rogge, D. Ingham, and C. Mayer-Boricke: Phys.

5)
6)

Rev. C, _!l, 1679 (1975).
R. DE. Leo, G. D'Erasmo, F. Ferrero, A. Pantaleo, and M. Pingnanelli: Nucl. Phys. A, 254, 156 (1975).
G. R. Satchler: Phys. Lett., 19,312 (1965); H. Sherif: Canad. J. Phys., 49, 983 (1971).

7)

C. Glashausser: Proc. 4th Intern. Symp. on Pol. Phen. in Nucl. Reac., p. 333, Zurich (1975).

8)

R.N. Boyd, D. Slater, R. Avida, H. F. Glavish, C. Glashausser, G. Bissinger, D. Davis, C. F. Haynes, and A. B.

9)Robbins: Phys. Rev. Lett., 29 , 955 (1972).
F. H. Schmidt , R. E. Brown, 1. B. Gerhart, and W. A. Kolasinski: Nucl. Phys.,2I, 353 (1964).

16

4-2.

Final State Interaction 1n Heavy lon Reactions

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

27 Al( 14
NUCLEAR REACTIONS
N, ~Q), 93 Nbci 4N, ~Q) E = 115 MeV,]
4
measured (d a/dE 1 dD 1 dE 2 dD 2 ) at 8 =8 = 50°. Final state Interaction
1 2[
analysis in terms of ~~ rescattering.

We have made an attempt to study the temporal and spatial size for light particle emissions
in low energy (~8 MeV/ A) heavy-ion reactions detecting directly two light particles in coincidence
mode.
Measurements were performed for the following reactions: 27 Alci 4N, an) and 93 Nbci 4N, ~~)with 115 MeV incident energy, using targets of 2.69 mg/cm 2 and 13.4 mg/cm 2 , respectively.
Four sets of counter telescopes which consist of 30 llm and 2000 f.Lm Si detectors were arrayed at
different azimuthal angles 1> but with the same polar angle 8=50° with respect to the beam
direction.

Correlations between any two sets were measured simultaneously. Thus, correlationsfor 24 and 30 different L¢ from 22° to 180° were obtained for the 27 AI + 14 N and 93 Nb + 14 N

reactions, respectively.
In the special case of E 1 =E 2 =E, where E

1 and E 2 are the kinetic energies of the two2~-particles in the laboratory system, the relative energy E
12 is given by E 12 = E sin 8 (1-cosL<t>)£ = 14 25 MeV

10 I

0

0
£ 12 ( MeV )

I

I

_[_

10

20

30

£ 12 ( MeV )Cross sections (d 4 a/dE 1 dD 1 dE 2 dD 2 ) for the reactions
27 Alci4N, Q~) and 93Nb( 14 N, QQ) at 8 = 50° plotted against theFig. 1.

relative energy E
E 1 = E 2 = E.

12 between two ~-particles with the condition

17

The cross sections of the ~-a correlation under this condition are plotted against E in Fig. 1.
12
There , we observe increases toward the left and right sides (i.e. 6¢=0° and 180°, respectively) ineach curve, which appear generally in heavy-ion reactions. A remarkable aspect is the enhancement
appeared at E 12 ;::::: 3 MeV in all curves, which corresponds to the 2+ resonance energyof 8 Be nuclet~s. Following two processes are examined as the origin of this enhancement:a) break-up of excited 8 Be nucleus b) final state interaction (FSI) between two ~-particles.

Wediscuss the first process.

The break-up cross section has been estimated using the cross sectionsof the 7 •9 Be productions and the Qgg rule 1 ) established generally in heavy-ion reactions andby assuming an isotropic distribution of a-particles after the break-up of excited 8 Be nucleus.
The value thus obtained was found to be 1/5 to 1/10 of the observed enhanced cross section.
In view of the difference of the cross sections , we concluded that the FSI is dominant. The
same effect is observed also at E 12 ;::::: 11 MeV which corresponds to the 4+ resonance energy.
To deduce a temporal information from the coincidence cross section, we apply the following
rescattering approximation. 2) First, an a-particle 1 is emitted to a direction w with an energy
1c 1 . After a time delay b.t, an emission of a second a-particle occurs with an energy c. greater
2
than that of the first, to the same direction w 2 = w . The second catches up the first at a1
distance D from the parent-nucleus, and, if the relative energy is around 3 MeV, we observe therescattering as the enhancement in the cross section. In this approximation, the enhanced crosssection over the background cross section is written by the following relation:

where the first term on the right hand side is the cross section for the emission of two primary
a-particles with energies E 1 and E 2 and toward the same direction (w = w ). The second is2
1
the cross section for a-a elastic scattering, which is 600 mb/sr at the 2+ resonance. The choice
E 1 = E 2 corresponds to the 90° scattering of two a-particles in their center-of-mass system.
The mean value of l/D 2 is expressed by the third term of which reciprocal has linear dependence
on a time constant r , if the time delay 6t is distributed as exp(- 61/r).

27AI ( 14 N a)
Bc. m. ~ 70 °g:{

The last is the Jacobian

NB( 14 N a )Bern. ~55 °

101

tn
>Q)
L

-....__
..D

E

•

100

OJ
~
lt.l
~

6

~

10- 1

T=4. 0 MeV
B= 110 MeV

T= 4.3 MeV
8= 4.0 MeV

Fig. 2.

Singles spectra for the reactionsa) and 93 Nbci 4 N, a) in thecenter-of-mass system.

27 Alci 4 N,

0
Ec. m.

18

for the transformations of the coordinates. The cross section ( d 4 a/ dE 1 ..... ) en is evaluated for
E = 14 - 31 MeV as a function of E, assuming the background properly. ForE< 14 MeV,
it is difficult to subtract the background without any great ambiguity; forE > 31 MeV, thestatistical error of the cross section is two large. The cross section (d 4 a/dc: 1 ..... ) is estimatedextrapolating the cross section at the energy set (c: 1 , c: 2 ) to .6¢ ~ 0°.
In the range of E = 14 - 31 MeV, we obtained r ~ 5 X 1o- 22 sec. nearly independentlyof E for both of the two reactions. In Fig. 2 are shown center-of-mass singles spectra of the27
Alci 4 N, a) and 93 Nb( 14 N, Q) reactions at ecm = 70° and 55°. In the energy range mentioned
above, these angles roughly correspond to e = 50° in the laboratory system. The spectra shownearly equal temperature T ~ 4 MeV when we fit them using the evaporation formula. 3 ) In
spite of the same temperature at e = 50°, the 27 Al + 14N system forms compound nucleus andthe 93Nb + 14N system is in preequilibrium state, according to the angle dependence of thesingles cross sections and of the temperatures. Series of experiments with other temperatures
and/or with proton detection are in progress.
It is necessary to consider also the spatial effect 4 ) of Q-particle emission for further
quantitative discussion.

References

2)

V.V. Volkov: Proc. Intern. Conf. on Reactions between Complex Nuclei, (Ed. by R.L.
Robinson et al.) Nashville, !L 363 (1974).
S. Kato, H. Orihara, S. Kubono, J. Kasagi, H. Ueno, T. Nakagawa, and T. Tohei: Nucl.

3)4)

Phys., Al95, 534 (1972).
T. Ericson: Advan. Phys.,_2_, 425 (1960).
H. Sa to and K. Yamazaki: to be published.

1)

19

4-3.

Study of a-Particle Emission 1n

14

N + 159 Tb CollisionI

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

e

4
4
159
N, 2axn), e N, 3an), E = 115 MeV;
Tbe 4 N, axn),
NUCLEAR REACTION[ measured a(E, ()), a-"f, a-"1-'Y coin; deduced a(Ea, ()a) in coin with final nuclei.

J

In recent years there has been considerable interest in fast (high-energy) a-particle emission in heavy-ion
collisions. Typical features of the above emission at relatively low bombarding energies, i.e., at 6 - 10 MeV/amu,
can be summarized as follows: (i) The angular distribution is strongly forward-peaked. (ii) The energy spectrum iscontinuous with strong enhancement at the high-energy part when compared with that expected in a nuclear
compound reaction. (iii) The rest of projectile and target nuclei fuse together, producing final reaction products
similar to evaporation residues.
Since the third feature is essential in fast a emission, the measurement of a-particles in coincidence with final
reaction products is particularly important. In the present work we have measured energy and angular distributions

115 MeV2

10cr<dl - 2 . cr<B Bel- 3 . cr <"'c*)

10

~

"

..0

10

2

E

~
"'0

....

(f)

"E
..0

b
"'0

c

"'0

"

10

b

"'0

-I

\0

-I

0 --'-16_0__jl80
14''- - - - I-20-'----__j\OO
0 -80
I O 0'--------::'"::-------'-----'6-

0

30

60

90

120

150

ISO

8cm (degrees)

8cm (degrees)

Angular distributions for various reaction
channels associated with a-particle emission in the14159
Tb + N reaction at 115 MeV: 159 Tbct 4 N, axn)
169
-xYb, x = 4, 5, 6; 159Tbct 4 N, 2axn) 165 -xEr,
Fig. 1.

x = 2, 3; 159 Tb{' 4 N, 3an) 160 0 y .
are to guide the eye.

Solid curves

Fig. 2. Lower: Experimental and estimated angular
distributions of 2axn and 3an channels. Upper:
Comparison of angular distributions of a-particles
for axn channels obtained in the inclusive andexclusive measurements.

20of a -particles at six different angles between 15° and 90° in coincidence with discrete -y-rays to specify various
4
4
159
14
N, 2cxxn),
N, cxxn),
Tb through reactions of
final nuclei produced in the 115 MeV N bombardment of2
159
4
Z ~ 2 werewithparticles
Chargedused.
wasthickness
in
mg/cm
2.1
Tb foil ofN, 3cxn). A metallic
and

e

e

e

detected with counter telescopes consisting of 50 J.lm and 2 mm Si detectors, while -y-rays were measured witha 75 cm 3 Ge(Li) counter placed in the reaction plane at 90° with respect to the beam.
Figure 1 shows angular distributions of a-particles in coincidence with -y-rays specifying final residual nuclei
mentioned above. The following points should be noted:
4N, cxxn) reactions depend very much on values of X. For instance,
The angular distributions of the(i)the yield for the cx4n channel shows a very rapid increase with the decrease of the emission angle, while the cx6nchannel has a much more flat angular distribution. This is considered to be due to kinetic energy dependence ofeangular distribution; in fact, the average energy of ex-particles corresponding to the cx4n channel is much higher
than that for cx6n as will be mentioned later.
4N, 3cxn) reaction is peaked around 35°, being similar to that for(ii) The angular distribution of theecarbon observed in the inclusive measurements carried out simultaneously. This indicates that the main origin
12
12
of a-particles observed in the 3cxn channel is break-up of an excited C( C*) into three a-particles.
4N, 2cxxn) reactions are also similar to those of Be. This fact(iii) The angular distributions of thect

8
together with that pointed out in (ii) suggests that the contribution of Be should be important in the 2cxxn

channel.
8
In order to clarify the above points mentioned in (ii) and (iii), we estimated the contribution of Be and12
C* in the following way. We first assumed that their angular distributions are the same as those of the
128corresponding isotopes. The yields of Be and C* are then assumed to follow the so-called Q gg systematics,
12
where the Q-value for 12 C is calculated for the 7.6 MeV state in C which is known to be the lowest excitedlevel to break up into three a-particles. We assumed further that a-particles originating from the break-up havethe same angular distribution as that for the parent nucleus. In spite of the very crude assumptions used, theresults thus estimated turned out to reproduce fairly well the experimental yields of a-particles leading to 2cxxn
and 3cxn channels as shown in the lower part of Fig. 2. The fact that the calculated angular distributions are
somewhat sharper than the experimental ones is clearly due to the last assumption mentioned above. We
128therefore conclude that a dominant part of 2cxxn and 3cxn channels originate from the break-up of Be and C*.
In other words, a-particles corresponding to the above reaction channels should not be included in the studyof the fast a emission.
As shown in the upper part of Fig. 2, the cross section of a-particles corresponding to cxxn (x = 4 - 6)channels amounts to about 80 % of the inclusive cross section when the above break-up contribution is subtracted.
A part of the difference must be attributed to the fact that all of the final nuclei were not included in the cx--ymeasurement, especially at forward angles, where very high-energy a-particles leading to the cx3n channel issignificant.
Energy spectra of a -particles leading to various final nuclei measured at 15° are shown in Fig. 3(a). The
average energy (Eav) for the cx6n, cx5n, and cx4n channels are 21.2, 23.7, and 31.6 MeV, respectively. The verysmall difference of Eav between cx6n and cx5n is due to the fact that the lower limit of a-particle energy for
cx6n is determined by the Coulomb barrier. The angle dependence of energy spectra is shown in Fig. 3(b) and3( c). The spectra for the same channel are similar to each other, being almost independent of emission angles.
This is quite natural because the Q-value is the most decisive factor to determine final residual nuclei. On theother hand, energy spectra obtained by summing up all cxxn channels depend very much on emission angles but
always have the following features characteristic of preequilibrium emission: the spectral shape is characterized by
a Maxwell-Boltzmann distribution and is thus similar to an evaporation spectrum with high nuclear temperature evenat forward angles. The temperature deduced from inclusive spectra in our previous works [ 1] increases smoothlywith the decrease of emission angles. However, the high-energy tails of the spectra at 15, 30, and 45° in Fig. 3(c)are quite similar to each other, which might indicate roughly the same temperature. This is considered to be
due to the lack of the cx3n channel which must be effective to very high-energy a spectra.

21

l~b

+

N 115 MeV

1

15 °

(0)

(b)
o.5n

CXAn

10
15°

>

~

06!t1

~

.......
..0

E

w

-o

75 °

4(o\~~~~· ~~t,

A

(c)

\

2CA3n

~

-o

~·

Ol6n

.......

No

-o

30°

r~":~

~,~+

t

- I

10

'tt
0

10

20

30
Ecm (MeV)

40

50

60

0

10

20

30

40

50

Ecm (MeV)

10

20

30

40

50

Ecm (MeV)

Fig. 3.
(a) Energy spectra of exclusive a-particles measured at 15° for the 159TbC4 N, axn) 169-xYb, x = 4, 5, 6,
and 159 TbC 4 N, 2a3n) 162 Er reaction channels.
(b) Energy spectra of a-particles measured at various angles for the 159 TbC 4 N, axn) 169 -xYb, x = 4, 5, 6,
159
TbC 4 N, 2a3n) 162 Er reaction channels. Solid curves are to guide the eye.
and(c)Energy spectra of a-particles obtained after summing up all axn channels.

Reference
1)

T. Nomura , H. Utsunomiya, T. Motobayashi, T. Inamura, and M. Yanokura: Phys. Rev. Lett., 40, 694(1978); J. Phys. Soc. Japan, 46, 335 (1979);
H. Utsunomiya, T. Nomura, T. Inamura, T. Sugitate, and T. Motobayashi: Nucl. Phys., A334, 127 (1980).

60

22

4-4.

Study of a-Particle Emission 1n

14

N + 159 Tb CollisionII

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

NUCLEAR REACTION 159 Tbct 4 N, axn) 169-xYb, E = 115 MeV: measured[ average r-ray multiplicities <M (E , e )>; average f. for a emission.
r a a
•

J

In the preceding report, energy and angular distributions of emitted a particles associated with 159 Tb

ct N, axn) -XYb reaction channels with4

169

X= 4 -

6 were presented.

In this report, we present average r-ray

multiplicities (<M,>) for preequilibrium (PE) a emission and discuss the resultant average initial orbital angularmomenta.
a-'Y-'Y triple coincidence measurement was performed using a 7.6 em X 7.6 em Nai(Tl) detector in addition
to a Ge(Li) and a detectors. The Nai(Tl) detector was mounted perpendicularly to the scattering plane, at 90°
to the beam and 50 mm from the target.
Table 1 summarizes values of <M > deduced for the 4 N, axn) reactions as a function of kinetic energy
1(Ea) and emission angle (e a) of a particles. The following points are to be noted. (1) Because any transitions
below the 2+ 64 Yb) or 13/2\ 163 • 165 Yb) states were not detected with the Nai(Tl) counter due to its energy
range covered, the given <M,> is smaller than the actual one by one or about three units for the a5n or a4n
and a6n channels, respectively. (2) <M,> for any energy bins remains almost constant for the change of ea inall reaction channels. ( 3) <M > for the a5n channel clearly decreases with the increase of Ea, while the Ea

ct

ct

1

Table 1.

Average r-ray multiplicities <M > as a funtion of Ea and ea
1
for the 159 Tbct 4 N, axn) reactions at 115 MeV.

channel

E *
a
(MeV)

a6n

16-20
{ 20-2413.4±4.2
14.0±6.6

a5n

16-20
20-24
24-28
28-32
32-36

19.1±2.0
16.8±1.6
13.6±1.7
11.4±2.2
9.2±4.6

24-28
28- 32
32-36
36-40
40 - 4415.0±5.3
14.6±3.6
13.5±2.3
14.2±2.812.9±3.5

Reactiona4n

II

Weighted
average
12.1 ±4.3
11.8±6.4
18.6±2.2
16.8±2.2
13.7±1.8
10.8±2.8
9.2±6.512.4±2.6
13.8±4.4
19.5±2.0
17 .0±1.6
13.4±1.7
11.7±2.2
10.0±4.2

16.4±7 .1
16.6±5.6
15.1±3.6

14.6±5.513.9±4.1
13.6±4.3

12.7±2.6
12.1±3.8
19.6±2.3
17.8±1.913.8±2.2
11.7±2.6

13.6±2.2
15.2±4.0
19.2±1.8
16.2±1.713.5±2.4
13.4±4.2

12.7±1.912.0±3.512.8±3.6
13.2±5.918.9±1.7
18.0±2.0
14.9±3.0
14.9±4.3

19.1 ±2.1
17.0±1.813.7±1.811.5±2.5
9.3±5.2
15.4±5.815.2±4.3
14.0±2.8
14.2±2.812.9±3.5* Energies given in the c.m. system.

dependence is much weaker for the a4n channel. The similar trend was also reported. in Ref. 1 .
The experimental values of <M > are related with the average angular momentum <J,> of "entry states"
1(levels prior to r-decays) in the following way. The entry states are usually considered to decay first by several"statistical" transitions, and then by stretched quadrupole de-excitations along the yrast line, or in bands pararell
to it. We therefore write< Jr >

2( < M > - < M > ) + f < M > + ] ,
r
s
s
s
o

(1)

23

where <Ms> is the average number of the statistical 1 rays and fs is the average angular-momentum decrease perstatistical transition. J 0 is a constant which depends on spin values of its very low-lying states. J 0 is taken to be
2h or 6.5h for even- or odd-mass nuclei , respectively.
As for values of <Ms> and fs , we follow an empirical analysis of Sarantites et al. 2 ) who obtained <Ms> =3.1 + 0.019E* for the estimate of <J > of final nuclei produced in (HI , xn) reactions , where E* is the excitation
1
energy of a compound nucleus before emitting neutrons. We shall use the same formula for the axn channels
by considering that E* denotes the excitation energy of intermediate states populated after the a-particle emission;
fs is taken to be constant (0.36), for simplicity, which is a value used in Ref. 2 for the 158 Gd + 12 C reaction
at 112 MeV.
Neglecting spins of projectile- and target-nuclei , we can relate <J > with the average angular momentum
1
<f.>
in
the entrance channel leading to the C 4 N, axn) reactions byI< f. >
1~< J >+ X 6, + 6. ,
r

n

(2)

a

where 6.n and 6.0' are average decrease of the angular momentum per neutron- and o-- emission , respectively.
It should be noted that they are not necessarily equal to average orbital angular momenta carried by neutron or
0'- particle .
The values of 6.n and 6.0' have been estimated by the statistical model calculation with the assumption thatan a-particle is emitted first in the preequilibrium stage of a complex nucleus (projectile and target) and thenfollows successive evaporation of x neutrons from an intermediate nucleus reachin g thermal equilibrium . The
preequilibrium nature of the a emission was treated as evaporation from a locally heated system (hot spot) .3 )More details of the calculation will be described elsewhere.
The energy dependence of <fi> estimated from Eqns. (1) and (2) in the case of ea = 15° is shown in
Table 2.

The values of < ei> averaged over both EO' and eO' are 32.3±6 .7 , 37.3±1.8, and 43.7±4.5 h for the a6n ,a5n, and a4n channels, respectively , clearly increasing with the decreasing number of neutrons emitted as is wellknown in the case of (HI , xn) reactions.

Since EO' leading to the a6n channel is low , a contribution from the

The weighted average of <f.>for a4n and a5n usingItheir cross sections is therefore considered as good indication for the average entrance angular momentum for fast
a-particle emission. The <f.>
was obtained to be 39 h.
Icompound reaction must be significant in this channel.

Table 2.

ReactionchannelEcm (MeV)Q

Angular momenta characterizing the 159 TbC 4 N, axn) 169- xYbreaction when a-particles are detected at 15° .

E*

<M >
'Y

< J > b)
n

<£>c)

(11)

(11)

25.9
27 .1

29 .5
30 .7

4 .5
4 .5
4.4
4.3
4.3

32 .8
28.2
22.0
17.7
13 .3

4.4
4.3
4 .2
4.2
4 .1

29.3
28 .6
26.6
28 .0
25 .6

<M s>

Range

Average a)

(MeV)

a:6n

{ 16-20
20 - 24

18 .1
21.7

76.1
72.5

13.4±4.2
14.0±6 .6

4 .5
4.5

cc5n

{ 16-20
20 - 24
24 - 28
28 - 32
32 - 36

18.4
22 .0
25 .8
29 .6
33 .5

75.8
72.2
68.4
64.6
60.7

19.1 ±2 .0
16 .8± 1.6
13 .6 ±1.7
11.4±2.2
9 .2±4 .6

cc4n{ 24 - 28
28 - 32
32 - 36
36-40
40-44

26.3
30.1
33.8
-37 .6
41.6

67.9
64 .1
60.4
56 .6
52 .6

15 .0±5.3
14 .6±3.6
13 .5±2.3
14 .2±2.8
12 .9 ±3.5

<J >
'Y
(11)

!:::.

< e.> d)

(11)

<ecc>

(11)

8 .1
10.5

5 .1
7 .3

0.630
0.695

34.6±8.441.2±13.2

37 .8
33.2
27.0
22 .7
18 .3

8.4
10 .6
12 .7
14.4
16. 1

5.4
7.4
9 .2
11.0
12.8

0.643
0 .698
0.724
0.764
0.795

43.2 ±4 .0
40 .6 ±3.2
36 .2±3.433.7 ±4.431.1±9 .2

33 .3
32.6
30 .6
32 .0
29 .6

12 .9
14 .6
16 .3
17.6
19 .0

9.4
11.1
12 .6
14.0
15 .2

0 .7290.760
0 .773
0 .7950 .80042.7 ±10 .6
43.7 ±7 .2
43 .2±4 .6
46 .0 ±5 .6
44 .8±7.0

Q

!:::.

Q

_ 0_!

l

a) Weighted average estimated from the energy spectrum at each reaction channel.
b) Average angular momentum of intermediate states populated after the cc -particle emission.
c) Average orbital angular momentum carried by cc-particle .
d) The given errors are only those associated with < M'Y > .

Table 3 compares the presently deduced values of <f.>
for fast a emission with some characteristic angularI
momenta in the entrance channel. The value of the critical angular momentum (Per) for complete fusion

24

calculated from models of Wilczynski 4 ) and Bass 5 ) who consider balance of forces at the close-contact region ofprojectile- and target-nuclei is around 50 has listed in the second column of Table 2 . Therefore, the present
result strongly indicates that <Ei> for fast a emission is close to, but slightly smaller than fer-

This is consistent

with interpretation that a- particles of interest are emitted in the precompound decay of a composite nucleus
which goes on the way to fusion but does not reach complete equilibrium yet. 6 )Average angular momenta <l!i> (in unit of h) leading to fast

Table 3.

a-particle emission and some characteristic angular momenta
in the 159 Tb + 14N reaction at 115 MeV.

<f.>exp

fer

fg/

37.3±1.8(a5n)52 (Ref. 4)

57

1

*

43 .7±4.5(a4n)51 (Ref. 5)

39 (weighted
average)48 (Ref. 4, 7) * *Deduced from an optical model analysis for elastic scattering of 14 N with 159 Tb.

* * Wilczynski-model using the half-density radius of Myers.?)

References
I)
2)

T. Inamura, T. Kojima, T. Nomura, T. Sugitate, and H. Utsunomiya: Phys. Lett., 84B, 71 (1979).
D.G. Sarantites, L. Westerberg, M.L. Halbert, R.A . Dayras, D.C. Hensley, and J .H. Barker: Phys. Rev.

c' 18, 774 (1978).
3)
4)
5)

R. Weiner and M. Westrom: Nucl. Phys., A286, 282 (1977).
J. Wilczynski: ibid., A216, 386 (1973).
R. Bass : ibid., A231, 45 (1974).

6)
7)

H. Utsunomiya, T. Nomura, T. Inamura, T. Sugitate , and T . Motobayashi: ibid. , A334, 127 (1980).
W.D. Myers: ibid., A204, 465 (1973).

25

4-5.

Angular Momentum Transfer and Alignment
Following Preequilibrium a
209

Bi

Emission in the+ 14 N Reaction at 115 MeV
H. Utsunomiya, T. Nomura, M. Ishihara ,T. Sugitate, K. Ieki,and S. Kohmoto

NUCLEAR REACTION209

Bie 4 N, af), E = 115 MeV;

[ measured angular correlations a(Ef, 8, ¢).

The measurement of the angular distribution for fission fragments in coincidence with reaction products
is known to give important informations on angular momenta involved in the nuclear reaction~) Dyer et al. 2 )first applied this method to heavy~ion reactions and successfully studied angular momenta transferred and theiralignment in deep -inelastic processes.
in heavy-ion reactions.

We applied this technique to the study of fast a-particle emission 3 )- s)

A 209 Bi metallic foil of about 800 J.J.g/cm 2 in thickness was bombarded with 115 MeV 14N beam provided
by the cyclotron.

a-particles were detected with Si 6E(50 J.J.m) - E(2 mm) counter telescopes mounted at 20°

and 50° with respect to the beam with half-angle acceptances of 3.4° and 4.9°, respectively.

Fission fragments

were detected with a thin Si(30 J.J.m) detector and measured at backward angles to avoid the elastically scattered
beam and eliminate the evaporation residues.
Figures 1 and 2 show the measured in-plane and out-of-plane angular distributions of fission fragments incoincidence with a-particles emitted at 20° and 50°.

The geometry of the experiment is the same as that inRef. 2.

x -axis was chosen along the recoil direction of fissile nucleus and z-axis along the normal to the reaction

plane .

8 and ¢ are usual polar and azimu thai angles, respectively.
In-plane anisotropy of the angular distribution obtained for a-particles emitted at 20° is larger than that at

50°, while out-;of-plane anisotropies at 20° are smaller than those at 50°.

This fact suggests that the alignment of

the transferred angular momentum in the case of a-particle emission at 50° is larger than that at 20°.
209

+

Bi

14

N

115 MeVI N - PLANE
I

I

v· ·----. . . . .

I

-

t

.....

........

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

I-

0

:--

-'
-

_j

w

-

50 °

>-

-

w
;:::::~_j101---

--=
:
-

w

0:::

I-

-

Fig. 1.

In-plane angular distributions of fission

fragments in coincidence with a-particles emitted at
120

I

I

I

I

I

150

180

210

240

270

cflcm(degrees)

20° and 50°, respectively.

The solid curves show

the best fit to the experimental data in the caseof one-dimentional disalignment.

26

OUT - OF

90

60

30

-

PLANE

209

B;

90

0

14

+

N 115 MeV

60

30

0

500

10

~

~
'of ~

1.0
252°

,I
i
i
fo}
'ol
~
,I ~ 1'of ~~ 237°

0

_J

~

~

>-

.

j!! lab

259°

244°

207°

•

175

182°

I O f-

~

90

60

30

-

I 0 f-

155°

0

90

e lab (degrees)Fig. 2.

~
60

30

-

162°

0

e lab (degrees )Out-of-plane angular distributions.

The angular distribution of fission fragments from a nucleus having the intrinsic angular momentum J whose
projections on the space-fixed z-axis and the nuclear symmetry axis are M and K, respectively, is usually writtenby I)

wMk ((J ) = ~ ( 2 J + 1 ) I d Mh ((j) 2 '

( 1)

1

where dM~ (8) are rotational wave functions. In order to analyze the experimental data we have to sum Eqn.
(1) over J, M and K. Dyer et al. 2 ) have shown that the experimental correlations are sensitive only to theweighted average J of the J-distribution when its weight function is proportional to 21+ 1 as is usually adopted.
In stead of doing the summation over J with the weight function, we therefore consider Eqn. (1) for J = J .

2 2

The K-distribution is assumed here to be given by exp(- ~ } where the width parameter K 0 can be estimated asa function of the nuclear temperature and the effective morrient of inertia, both taken at the saddle point
deformation. I)' 6 ) Following the procedure given by Back and Bj¢rnholm, 6 ) we obtain K 0 ~ 11 h in the present2

case.
As for the summation over M, we follow the semi-classical treatment of Dyer et al.; 2 ) that is, the shape of

IMI = 1 angular correlations is taken from Eqn. (1), and a classical prescription is used to account forM =f J
If the spin direction is given by polar angle ~ and azimuthal angle f1 (i.e., Mx = J sin~ cos f1 and
My = 1 sin.~ sin fl), the angular distribution in the c.m. system of the fissioning nucleus is then given bycomponents .

Kz

W((J,¢ ) oc

J

I: P ( (, r; ) I: _ e

~1

(J' =

with

~-J

- 2Kg

J

W-

( (}' )

(2)JK

cos - 1 { cos(Jcos( + sin(Jsin((cos¢conr;+sin¢sinr;)}.

(3)

A weighting factor P(t fl) is determined through the M-distribution which is assumed here to be proportional toexp( -~ 2 /2~ 2 ) with ~00

as parameter to be adjusted because the most plausible mechanism giving rise to the27disalignment is a non-equatorial collision as discussed in Ref. 2, producing preferencially MY (= J sin~) components.
Solid curves in Figs. 1 and 2 show the best fits for simultaneous fitting of Eqn. (2) to the measured in-planeand out-of-plane angular distributions of fission fragments. We fixed 11 h for the value of K 0 in the fitting
procedure. The resultant values of the best fit parameters are listed in Table 1. It turned out that the angularmomenta of the amount of 31 ±3 h and 26±3 h are transferred in the present reaction when a-particles are emitted
at 20° and 50°, respectively. If we assume that the angular momentum of the initial system is divided between
a-particle and 10B in proportion to their masses, the average entrance angular momentum ( <P>) responsible fora emission at 20° and 50° can be deduced to be 43±3 hand 36±3 h, respectively. From the comparison of thosevalues with the critical angular momentum(ecr) for complete fusion which is calculated to be 50 h on the basisof the liquid-drop model, 7 ) we can conclude that the average £-values in the entrance channel responsible fora emission are close to , but slightly smaller than fer' being consistent that fast a-particles in the present reaction
originate from the collisions with impact parameters ensuring enough overlap of projectile and target nuclei tofuse each other.

Table 1.

Best fit parameters J and ~0

together with the resultant values of alignment

Pzz and average entrance angular momentum <£> for preequilibrium aemission.
Emission angleof a-particles

Errors estimated from the x2 -values are also given for J.

~0(degrees)

-

J

p

zz

(h)

<£>
(h)

20°

62.1

31±3

0.39

43 ±4

50°

29.4

26±3

0.69

36±4

The disalignment of J in the y-z plane was determined by the parameter ~ . It is remarkable that for0
a emission at 20°, a large disalignment (~ 0 = 62.1 °) was found compared with that (~ = 29.4°) at 50°. The
0alignment parameter Pzz = 3<M~> / 2<J2>- 1/2 is also listed in Table 1, which is unity for fully aligned J
and zero for isotropically oriented J. Pzz of 0.69 was obtained for a emission at 50°, which is rather close to thevalue of 0 .6 - 0.8 obtained for deep inelastic reaction?) However, Pzz for a emission at 20° was 0.39, which
is much smaller than the above values. It seems that the present data shows the large contribution of anon-equatorial collision to a emission at forward angle.

References
1)
2)

R. Vandenbosch and J. R. Huizenga: Nuclear Fission, Academic Press, New York and London (1973).
P. Dyer, R . J. Puigh, R. Vandenbosch, T. D. Thomas, M. S. Zisman, and L. Nunnelley: Nucl. Phys.,A322, 205 (1979).

3)
4)

H. C. Britt and A. R. Quinton: Phys. Rev. , 124, 877 (1961).
L. Westerberg, D. G. Sarantites, D. C. Hensley, R. A. Dayras, M. L. Halbert, and J. H. Barker: .ibid., C18,796 (1978).

5)T. Nomura, H. Utsunomiya, T. Motobayashi, T. Inarnura, and M. Yanokura: Phys. Rev. Lett., 40, 694(1978); H. Utsunomiya, T. Nomura, T. Inarnura, T. Sugitate, and T. Motobayashi: Nucl. Phys., A334,
127 (1980).

6)7)

B. B. Back and S. Bjolnholm: Nucl. Phys., A302, 343 (1978).
R. Bass: ibid., A231, 45 (1974).

28

4-6.

Polarization of Preequilibri um Proton Emission
in

the

93

Nb +

14

N

Reaction

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

93
NbC 4 N, p) , E=95MeV; measured a(E, 8),]NUCLEAR REACTION[ spin polarization (8=20°). double scattering method.

Light particles such as p, d, t, and a emitted in heavy-ion reactions often exhibit forward-peaked angular
distributions and continuous energy spectra enhanced at high-energy parts compared with those expected in
14
3compound nuclear reactions.l)- 3 ) In our previous work ) on N-induced reactions at 6 - 8 MeV/amu,
the energy spectra in question were well interpreted as those of preequilibrium (PE) emission from a locally
3 4heated nuclear system in the framework of the hot-spot model. ), ) We have measured for the first time spin
14
93
polarization of protons emitted at 20° in the Nb + N reaction at 95 MeV by the double scattering method ,in order to gain more insight into this phenomenon.
14
A 9 mg/cm 2 thick Nb foil was bombarded with 95 MeV N-beam with a few hundred nA from thecyclotron . The beam energy at the centre of the target is about 88 MeV.
The polarimeter used in the present work is described elsewhere in this progress report. The left-rightasymmetry was measured at 20° on both sides with respect to the beam direction and was deduced in theconventional manner using the geometrical average of the asymmetries obtained at 20° and 340° in order to5cancel most possible false asymmetry to first order. ) The effect of false asymmetry is estimated to be less than 2%.
We have also measured energy spectra of protons at various angles. Figure 1 shows angular distributionsin the c.m. system as a function of proton energy. They are nearly symmetric with respect to 90° for low
energy protons up to 10 MeV , but become more and more forward-peaked with the increase of proton energy.
Figure 2 (a) shows the energy spectra measured at 8lab = 20° and 156° corresponding to eem = 22° and
158° on the average. Protons emitted at 8lah = 156° are considered to originate mainly from a decay ofcompound nucleus. Then the difference between these two spectra is considered to represent an energy
spectrum from the PE process of interest. This spectrum can be well fitted by the evaporation formulawith temperature (T) of 3.5 MeV as shown by a smooth curve. The proportion of the PE component increases
smoothly with the increase of proton energy , for instance, from 12 % at 7 MeV to 83 % at 20 MeV.
Figure 2 (b) shows the experimental polarization; they are 1.0 ± 3.8, 3.5 ± 3.7, 8.2 ± 3.4, 11.0 ± 5.8, and18.6 ± 7.1 % for energy bins of 6.5 - 8.5, 9.2 - 10.9, 11.5 - 13.7, 13.7- 16.4, and 16.4- 20.5 MeV in thec.m. system, respectively. We follow the Madison convention for the sign of polarization.
This energy dependence is considered to originate mainly from the energy dependent proportion of the
PE component mentioned above . Assuming that protons emitted in a compound reaction are unpolarized
and the PE protons are polarized by +22 % independent of their energies, we obtain a solid curve shown in
Fig. 2 (b) which agrees well with the experimental result.
Now we present a macroscopic explanation of the present result based on the hot-spot model. We firstpoint out that if a total angular momentum of a highly excited nucleus is polarized, the intrinsic spin of
nucleons emitted during its statistical decay is usually polarized in the same direction. To see this, we consider,for simplicity, a stretched downward transition by proton emission with kinetic energy E and total (orbital)
angular momentum j( e), for which the transmission coefficient is given by T ej(E). Then, the polarization
P of the evaporated protons can be given by

29

93

Nb + 14 N( 95MeV)

-l?_
..0

E

14- 16 MeV

8 c. m. ( Degrees )Fig. 1 . The double differential cross sectionsof protons obtained for given c.m. energies
are shown for the 93 Nb + 14 N reaction at
95 MeV.
eye.

Solid curves are to guide theFig. 2.

Upper: Experimental energy
spectra of protons obtained at (}Jab = 20°
and 156°, corresponding to (}= 22°
em
and 158° on the average. Solid curves
are to guide the eye. The difference
between these two spectra is also shown,for which a solid curve given is the best
fit by the evaporation formula withtemperature of 3.5 MeV. Lower:
The measured (circles) and estimated(solid curve) values of proton
polarization.

Horizontal lines for theexperimental points show the size of energy
bins. The given errors are only statistical.
See the text for the estimated curve.

where f 1 is the initial polarization of the parent nucleus.
positive, P has the same sign as f .
1

Since the numerator within the bracket is usually
For the present reaction we have carried out more general statistical

calculation, then we obtain P = (0.2 - 0.3) X f .
1
Now we suppose a case in which a projectile is captured by a target nucleus in a nearly peripheral
collision of which the impact parameters fall between those of deep -inelastic and compound reactions. We
assume that local heating occurs around the contact region of the two nuclei and that a hot spot is finallycreated on the surface of this composite nucleus which is also rotating due to transfer of initial angular momenta.
The relaxation time due to diffusion of heat estimated in Ref. 4 becomes 4 X 10- 22 sec for a hot spot at
T = 3.5 MeV on the surface of an A~ 100 nucleus, while the present statistical calculation shows that the inverseof the evaporation probability of the hot spot is the same order of magnitude. We therefore postulate that
protons of interest are evaporated from the hot spot, but not from the other cold part of the system. It is
expected that the above emission is not isotropic, but occurs near the tangential direction on the average. Suchevaporated protons must be polarized, as pointed out above, in the same direction as that of the rotation of thecomposite nucleus.

The positive sign of the presently measured polarization thus indicates that the relevant

PE proton emission takes place at negative angles as is the case for deep-inelastic reactions.

This is reasonable30

because the impact parameters involved are even smaller than those for deep-inelastic collisions.
Finally we note that no polarization is expected if the whole surface of the composite nucleus is heatedand contributes to proton evaporation equally. The present result is therefore considered to be evidence forthe hot-spot formation, as long as the relevant reaction mechanism can be described in terms of two-stepprocesses, that is, formation of a highly excited nucleus and its statistical decay.

References
1)
2)
3)

4)
5)

H.C. Britt and A.R. Quinton: Phys. Rev. , 124, 877 (1961).
T. Inamura , M. Ishihara, T. Fukuda, T. Shimoda, and K. Hiruta: Phys. Lett., 68B, 51 (1977).
T. Nomura, H. Utsunomiya, T. Motobayashi , T. Inamura, and M. Yanokura: Phys. Rev. Lett., .±Q, 694(1978); H. Utsunomiya, T. Nomura , T. Inamura, T. Sugitate, and T. Motobayashi: Nucl. Phys. , A334,
127 (1980).
R. Weiner and M. Westrom: ibid. , A286 , 282 (1977).
G.G. Ohlsen: Proc. 4th Intern. Symp. on Polarization Phenomena in Nuclear Reactions, Zurich, p.287(1975).

31

4-7.

Spin Alignment

1n Heavy lon Reaction

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

NUCLEAR REACTIONS 159 Tbe 4 N, HI), E = 115 MeV; measured )'-coin ;( in-plane and out-of-plane; deduced spin alignment.

J

The present study is concerned with spin alignment of the residual nucleus. We have measured angular
distribution of )'-rays coincident with heavy ejectiles (2 ~ Z :;; 7) in 159 Tb + 14N reaction.
A self supporting 159 Tb target of 4 mg/cm 2 in thickness was bombarded with 115 MeV 14 N beam from thecyclotron . Emitted particles were detected with counte r telescopes of 50·- 2000 ,urn Si detectors fixed at 40° fromthe beam direction. Coincident )'-rays were measured with a Ge(Li) detector at 11 angles in the reaction plane
and at 11 angles out of reaction plane.
Typical angular distributions of )'-rays are shown in Fig. 1. Strong anisotropy is found not only inout-of-plane correlation , but also in in-plane correlation in every final channel. This fact indicates that spin vector
is aligned in a complicated way, which is far different from isotropic or cylindrical distributions. To extract.O,:.:..IN::_
PLA=--::.:.:NE=-------=-=(a.:_) -----,
2159
Tb( " N, 12 Cxn l 16 ' - • Dy,:..
<1>_= -=0o--'(-=-b)_---,<1>=90°

INPLANE
2.0 .-------

(c)

18

18

16

16

14

14

~ 12 r---..g

~ 10

~Q

~ 08

9--

( b)

<1>= 90°

(c)

~ 10
~ 08

0.6

0. 6

0.4

0.4

0.2

00

<1>=0°

~ 12

rv

~Q>!

(a)

- -- -- - - - ,159
Tb( " N, axn ) 169 - ' Yb

0. 2

o

30

60

90

120

30

!50

60

e,,b ( deg)<l>1,b ( deg )

900

30

60

o,,~.

( deg)

90

O. 0 ~
0 -----:3~0-60~---;6
90:---1:-!::2:::0~
15"
0 ___j<t>,,b ( deg )L--!----,3~0~6L,-O----,-J90
e,.b ( deg)

(I)

2.0
1.8

INPLANE(a)
159 Tb(" N, 12." Cxn l 16 0 Dy 4'-+r

0

30

60

90

e,,b ( deg)(2)

<1>=0°( b)<1>=90°. .JN_P_
LA_NE_ __ (a_) - ----, ,.::_¢_=~
0°_(:_::b.:_
) -~
20
159
Tb( 14 N, G 5 1J ) 164 Yb4-+ 2
1.8

( c)

1.0

1.6

-:::::1.4

14

§ 1.2

· ~ 120r-¢ _= .:::_:
90:____::<c::_:_
)-

---,

>-

~ 1.0

~ 10

~ 08

·~ 0.8

0.6

0.6

0.4

0. 4

0.2

O.Oo

0.2
30

60
90 120</>1,. ( deg )

150

30

60

e,.b ( deg )

900

30

60

e,•• < degl

90

00

o

30

60

90

120

150

( 3)

0

3060900

306090e,•• < degl
( 4)

Fig. 1. Angular distributions of )'-rays. (a) is a distribution in the reaction plane. (b) is a distribution
in the plane perpendicular to reaction plane and containing the beam axis. (c) is a distribution in theplane normal to the beam direction. Polar coordinate with z-axis normal to the reaction plane andx-axis to the beam direction is chosen in Lab. system. Yields are shown in arbitrary units. The curves
are fits to the data (see text). Four reaction channels are shown:

(1)
(2)
(3)
(4)

an energy integrated )'-ray distribution coincident with C;
an energy integrated )'-ray distribution coincident with a;a )'-ray distribution of 160Dy 4+ ~ 2+ transition coincident with C;a )'-ray distribution of 164Yb 4 + -+ 2 + transition coincident with a.

32quantitative informations of spin alignment from 1 -ray angular distributions, we performed following analysis.
With polar coordinate , angular distribution W(8¢) of 1-rays emitted from oriented states is expressed ingeneral as(1)

W((}rp ) = LAq ( 2A + 1 )- l/2 AA(r).OAq y *Aq((}rp ) 'where Pt._q is statistical tensors of rank 'A, which represent substate. population of 'Y deexciting state and Y*A.q are
where L, L' arespherical harmonics . The angular distribution coefficient At._ depends only on L, L', ji,
multipolarities of 1-ray and jiQf) is an angular momentum of initial(final) nuclear state. Eqn. (1) gives a relationh·between W(8¢) and spin alignment for a transition of given L, L', ji, h· In the case of continuum 1-rays, however,
it is rather difficult to specify ji and h· In the present case , residual nuclei (i.e. Yb, Dy) are known to have goodrotational properties , so that observed 'Y-rays of low energy ( ::S 1.5 MeV) may be mostly attributed to stretched
E2 transitions. In the case of L = L ', h = ji - 2, a transformationp{ (2A + 1 ) (2ji + A+ 1 ) ! ( 2ji - A )
l

AQ

(

j .)

I }

- 1/ 2(2)

1

C 2j . ) I
1leads tow ( (} rjJ ) ex: I: Aq A A jJ Aq ( j i ) y *Aq ( (} rjJ )
I

'

(3)

where A' A is independent of ji. Note that ji is only implicitly contained in Eqn. (3). We fitted 1-ray angular
distributions to Eqn. (3) by least square method with Pt._q Ui) as parameters. Using Pt._q Ui) obtained, we further
deduced a spin alignment parameter Pzz and its width a defined by
p

3

zz

2

2<m >

1

I . 2
Ji

(4)

2

and

a 2 = (< m 4 >- < m

2> 2 ) ; J.· l 4(5)where <mi> is a i-th moment of magnetic substate m. P zz characterizes spin alignment to z-axis and has avalue between - 0.5 and 1, e.g. Pzz is positive for prolate alignment , negative for oblate alignment and zero for
isotropic spin distribution. To investigate spatial spin distribution, we expressed Pzz and a for following threedifferent z-axes:(a) normal to reaction plane;(b) recoil direction;(c) normal to both (a) and (b) directions.

These three directions are orthogonal to each other, and a relation holds from the definition . The three
dimensional distribution pattern of spin vectors may be characterized in a quantitative way in terms of thesethree P zz 's. When the distribution of the spin vectors have axial symmetry with respect to one of the three axes,
other two axes are equivalent and have the same P values . For some typical cases, expected Pzz values arezztabulated in Table 1: i) is the case for uniform spin distribution in the (a) -(c) plane, and ii) is the case for purepolarization with respect to (a) - axis .

Pzz(a) + P (b) + Pzzzz(c) = 0(6)

Analyzed ~:esults are shown in Table 2. Errors from least square fit are smaller ~han 0.01 and omitted.
Energy integrated 1-ray distributions are analyzed for different bins of particle energy. "Average" means weighted
value with inclusive yields.
In every channel Pzz(a) is positive, indicating an orientation favorable for (a) - axis. However, the size of
Pzz (a) is about 0.2 - 0.3 and appreciably smaller than P zz = 1 expected for pure polarization. In these cases the197
136
Xe + Auvalues of the ratio R = W(() = 0°) I W(() = 90°) are 0.6 - 0.9 and similar to those obtained for thereaction by Aguer et al. 1)

In Re f. 1 as well as in other works, Pzz (a) was determined simply from the value of R
by assuming axially symmetric Gaussian distribution of the spin vector with respect to (a) - axis. For instance ,Pzz (a) = 0 .25 corresponds to R = 0 .75. We note that the value of R strongly depends on the direction angle ¢so that such an analysis as in Ref. 1 may be sometimes misleading.

33

p zz value for typical cases.

Table 1.
Pz/a)pzz(b)

pzz(c)

i)0.25- 0.50

0.25

ii)

1.00

-0 .50-0.50

Table 2.

Alignment parameter Pzz and its width a.

Continuum '}'-rays
Emittedparticle

12c

Be

Energy
(MeV)

p

a

zz

(a)

(b)

(c)

(a)

(b)

(c)

{

80-90
90- 100
Average

0.20
0.22
0.21

- 0.04- 0.1 2
- 0.07- 0.16-0.10- 0.13

0.26
0.18
0.23

0.38
0.36
0.37

0.26
0.21
0.24

{

80- 9090-100
100Average

0.24
0.23
0.24
0.24

- 0.14- 0.1 2
- 0.30-0.17-0.09- 0.11- 0 .06- 0.09

0.31
0.22
0.19
0.23

0.36
0.36
0.21
0.32

0.28
0.32
0.31
0.31

20-25
25-30
30-35
35Average

0.21
0.26
0.34
0.36
0.27

- 0.18-0.17- 0.25- 0.33-0 .22- 0.03- 0.09- 0 .09- 0.33- 0.06

0.26
0.29
0.28
0.22
0.27

0.34
0.35
0.29
0.19
0.31

0 .28
0.27
0.31
0.29
0.28

Inspection of three Pzz' s may help to visualize the three dimensional pattern of spin distribution. In thecase of a-particle channels, rather large negative values are obtained for Pzz (b) indicating oblate spin alignment
with respect to (b)-axis. Together with a relating large positive value of Pzz(a), the spin orientation may besupposed to have roughly a sector shape distribution in (a) - (c) plane with direction (a) favored. In the caseof C-channels, values of Pzz(b) and Pzz(c) are rather close to each other indicating a more symmetric spin
distribution with respect to the (a) -axis. We also note that P 's show a systematic dependance on Q-value.
zz
As the particle energy decreases, Pzz (a) becomes smaller and P (b) larger towards positive. The latter resultszzcomplies with the fact that (b) becomes larger with increasing inelasticity and may imply that the spin distribution
becomes less confined in the (a) - (c) plane with increasing inelasticity of the reaction . This observation may berelated to the fact that for larger negative Q-values the contact time of the colliding ions becomes longer so thatthe direction of transferred momentum may be more randomly distributed.
In the present preliminary analysis stretched E2 transitions were assumed for continuum '}'-rays. It was
shown that the spin vector distribution generally has a complicated pattern which does not have simple
symmetries. The present analysis in terms of three Pzz 's may work as a simple method to represent such a
distribution.

Reference
1)

P. Aguer, R. P. Schmitt, G. J. Wozniak, D. Habs , R. M. Diamond , C. Ellegard, D. L. Hillis , C. C. Hsu , G. J .
Mathews, L. G. Moretto , G. U. Rattazzi , C. P. Roulet, and F. S. Stephens: Phys. Rev. Lett., 43, 1778
(1979).

34

4-8.

20

Reactions between

Ne and5°Cr

Y. Nagame, I. Kohno, M. Yanokura,
H. Kudo*, and H. Nakahara

20

5

NUCLEAR REACTIONSNe + °Cr, Elab = 146, 93 MeV
measured charges 6:SZ:S20, cross section, energy spectra,(
angular distribution, charge distribution.

J

It has been predicted theoretically by Cohen et al.l) using the rotating liquid drop model that the large

angular momenta involved in heavy ion reactions are expected to lower the fission barrier of rotating compound
nuclei sufficiently to make fission a competing deexcitation process. For relatively light nuclear system,compound nuclear fission is predicted 2 ) to occur only at high angular momenta because the fission barrier, as
calculated by rotating liquid drop model, 1) decrease rapidly with increasing angular momentum. It is, however,difficult to distinguish fission from deeply inelastic process that involve both a large amount of mass transfer
and an interaction time of the order of several rotations, resulting in a 1/sin () angular distribution in the c.m.
system. According to the rotating liquid drop model, the angular momentum dependence of fission barrierheight varies with the fissility (Z 2 /A), where Z and A are the atomic number and mass number of the fissioning
nucleus. Therefore, we have been studying the systematic changes of the energy, angular and charge distributionsof emitted particles as a function of the fissility and incident projectile energies. In the previous paper ,3> theisotopic dependence of the cross section for heavier products (Z:=::J 1) was observed using the reaction system of
115 MeV 14N + 58 Ni and 14N + 64Ni.

7\ 1
llOI ~ i JO I:t\ iwf/\ 1
Blab=20o1
102r-----~~-r---~_ !OJ

j

/\

I

I

I

I

I

ec.m.=40°

50-

40 -

>
Q)

Li =sonro = 1. 225
d = 4.5fm

•• •

-

-

L

30-

-

e

kl..;
v

10

l 0 1JO' z~~
~

100

50

100

E lab. ( MeV )Fig. 1. The energy distributions of products(Z2:-:11) at ()lab = 20° in the reaction of
146 MeV 20 Ne + 5°Cr.

z
Fig. 2. The most probable kinetic
energies as a function of the productcharge for the system 146 MeV 20 Ne + 5°Cr.
Comparison with a result of calculation
including the Coulomb (Ec) and centrifugal (E e)components (d = 4.5fm).

* Tokyo Metropolitan University.

35

In this study, the bombarding energy dependence, i.e., angular momentum dependence has been investigated,
especially for heavy products (Z2:J 1), with the 20 Ne + 5°Cr reaction system whose fissility (Z 2 /A"'"' 16) is close to
the previous system. The critical angular momenta ( ecr) for fusion calculated by Bass model 4 ) are 53h and 40h
for the 146 MeV 20 Ne + socr system and 93 MeV 20 Ne + socr system, respectively. The liquid drop fission
barrier at the fer' calculated from Ref. 1 are 4 MeV and 17 MeV for 146 MeV system and 93 MeV system,
respectively. From these values the fission cross section for 146 MeV 20 Ne + so Cr is expected to be larger
than that for 93 MeV 20 Ne + socr.

An enriched self-supporting 5°Cr target of 500,ug/cm 2
thickness was bombarded with Ne + ions at beam energies of 146 and 93 MeV. The reaction products weredetected with lili-E counter telescope consisting of a gas proportional fill and a 300,um thick solid state E
detectors). The products with atomic numbers from 6 to 20 could be identified in the bombardment of 5°Cr
by 146 MeV 20 Ne, and the energy spectra, angular and charge distributions of products were obtained.
Figure 1 shows the energy distributions at 8lab=20° for z::=:11. The single bell-shaped kinetic energy peaksin the region of the strongly damped collisions were observed for the products with z:=:12. The observed mostprobable kinetic energies at 8 c.m.=40° were indicated by solid circles in Fig. 2 as a function of their atomic
numbers. The kinetic energies calculated by Coulomb (Ec) energy and centrifugal force (Ep) which was obtainedusing the sticking model are shown by solid curves in Fig. 2. The good agreement for heavy products is obtainedwith d=4.5fm and f i=50h (""e cr), where d is the deformation factor and ei is the initial angular momentum. Thislarge d is interpreted as representing a large deformation of the fragments at the scission point. The angular
distributions for the products with z:::14 show almost constant distributions in the c.m. system (Fig. 3) . Thus theseproducts (Z~14) are considered to be either fusion-fission fragments or fragments emitted after interaction times
that were longer than the time required for one rotation of the composite system. The charge distributions forvarious angles are shown in Fig. 4.
The experiments were performed at the cyclotron.
620

In 93 MeV 20 Ne + socr system, the contribution of strongly damped components or fusion-fission components
could not be observed.

It is considered that these results reflect some effects of angular momentum dependence.

~

I

I

I

I

I

l

lOI
10'1

~=12
• 2=13146 MeV-6~---..._
.D

E
CD
""ti

b""ti

5f

•

.•

51
51

•

5£

•

51

..

. . . • 2=151..

2=163:•

2=17.. •• •

5t
!Ol

I

•

.2=18

• •
20

I

30

I

40

:

50

I
l

.2=19[
21=201

• • •
I

20

Ne+ 5 °Cr

2=141t;J 103

-ocu

-:::_

.D

E

'N 102
""ti

ci:,
""ti

b-

~ 10 1I

60

70

ec.m. (deg)Fig. 3. The center-of-mass angular
distributions for different charges producedin the reaction 146 MeV 20 Ne + socr.

Fig. 4. The charge distribution at different centerof-mass angles for the system 146 MeV 20 Ne + socr.

36

We are now studying the system of 120 MeV 20 Ne + 5°Cr reactions to investigate the angular momentum dependence
in more detail.

References
1)

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

2)

F. Plasil and M. Blann: Phys. Rev. C, l_!, 508 (1975).

3)
4)

M. Yanokura, H. Nakahara, and I. Kohno: J. Phys. Soc. Japan, 50,369 (1981).
R. Bass: Nucl. Phys., A231, 45 (1974).

5)

M. Yanokura, I. Kohno, H. Nakahara, and K. Yamakoshi: Oyo Buturi, 49, 1095 (1980).

37

4-9.

Recoil Range Distributions in the Reaction Inducedby 115 MeV 14 N on

62

Ni

Y. Nagame, M. Watanabe,* H. Kudo,* H. Nakahara,
I. Kohno, and M. Yanokura

4
NUCLEAR REACTIONS 62 NiC N,x), E=115 MeV, measured( projected recoil ranges, measured cross sections.

62
14
The nuclear reactions induced by 115 MeV N ions on Ni target have been investigated using recoil
technique. The heavy products from fusion-evaporations and transfer reactions could be separated by2
62radiochemical methods. The enriched Ni target of self-supporting 900 J.1g/cm thick metalic foil was prepared
14 5
by the electrodeposition method. The bombardments were performed with N + ions accelerated in thecyclotron at the energy of 115 MeV for 10 to 15 h. The recoil ion ranges projected to the beam direction2
were measured by placing the target and a stack of 200 J.1g/cm thick AI catcher foils in front of a Faraday cup.
For Co and Sc isotopes, the 'Y-ray spectrometries were performed after chemical separations, while other heavy
products were directly measured with Ge(Li) detector.
The range distributions were obtained for each reaction products as shown in Figs. l, 2.

In Figs. 1, 2, the

10 4
t2
Q)

c
..::.:.

u:..E

f.........

10 4

]:'
·:;: 10 2:..:::;
u

73

<(

Se

( b)
EcN

1

10
104

~

Q)

c

!

103

..::.:.
u:..Ef-.........

103

]:'
·:;:
:..:::;
u
<(

102
10 1

mg/ cm 2

Fig. 1.
690

1.0
mg/ cm 2

3.0

71·
rest'd ue pro duc t s: (a) As,
Projected recoil range distri butions o f evaporatiOnGe, and 67 Ga; (b)* Tokyo Metropolitan University.

73

Se.

38

55

Co

EcN

~

Ec Ec+ELt t

r 0 = 1.225

d =2.0fm/z= 471i

EcN

(f)
(f)
Q)

~
u

1.0

E

f--

------~·;;:-_;:::;uGo++t~+++

++

<(

co

+

+

0.5

+titi

0

~

E cN

~

EcN

1.0

1.0

mg/ cm 2

2.0( AI )

0.5
(a)

0

1.0

mg/ cm 2

Fig. 2.

mg/ cm 2

Projected recoil range distributions of transfer reaction products : (a) Co isotopes~(b) Sc isotopes.
vertical arrows labeled EcN indicate the range which would correspond to a full momentum transfer reaction ,i.e ., compound nucleus formation. The range-energy relationship is deduced using Northcliffe and Schilling
tables. I) The arrows labeled Ro designate the average range obtained in this experiment. The range
distributions of the evaporation residue products collected in Fig. 1 (a) show typical Gaussian distribution and
R 0 is close to EcN· These results can be considered as an evidence for compound nucleus formation . On theother hand, the short mean range of 73 Se in Fig. 1 (b) can not be accounted for compound nucleus formation.
This suggests that the pre-equilibrium particle emissions from composite system have occurred. The mean rangeof each Co isotope in Fig. 2 (a) is considerably shorter than that expected by full momentum transfer reaction.
This includes the possibility of a predominant contribution from direct transfer reactions. The range distributionsfor Sc isotopes are shown in Fig. 2 (b). The arrows Ec and Ec + E e indicate the range which would correspondto Coulomb energy and Coulomb energy plus centrifugal energy, respectively. The parameters used for the
calculations of the sticking model are also shown in Fig. 2 (b).

The mean range of Sc isotopes is close to therange expected by Ec + E e' and these Sc products are considered to be either fusion-fission fragments or strongly
damped fragments. The peaks in the shorter ranges in Fig. 2 (b) are assumed to be the contribution from
impurity in Al catcher foils. The cross sections for Co and Sc isotopes were obtained as shown in Fig. 3. The
arrows labeled T and CN indicate the N/Z ratio which would correspond to the target and composite nucleus,
respectively. The equilibration of N/Z ratio for Co and Sc isotopes were close to that of the composite nucleus.
The Qgg dependence of transfer reaction products (Co isotopes) is obtained except for 6°Co isotope as shown in
Fig. 4. The nuclear temperature estimated by these isotope production was deduced to be 2.3 MeV from thefollowing expression2 ):a ex: exp { (Qgg + fillc)/T} .

According to the statistical hypothesis concerning the Qgg systematics, the production of 6° Co isotope isconsidered to be more direct transfer reaction than that of other Co isotopes.

39

:0
E
b

CN

l

T

0t

:0
E
b

/

(b)

1

\

A

Fig. 3. Cross sections as a function of mass number: (a) Co isotopes; (b) Sc isotopes.
Solid lines are drawn to guide the eye .

...0

E
b

1 0 - 2 L-~--_J--~----~--L---~

-1 0

-20

Qgg + 6. Ec ( MeV )Fig. 4. The Qgg dependence of Co
isotopes. L).Ec indicate the changeof Coulomb interaction energy.

References
1)
2)

L. C. Northcliffe and R. F. Schilling: Nucl. Data Tables, A7, 233 ( 1970).

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

40

4-10.

Correlation between the Fragment Mass and the Angular
Anisotropy in

the Proton-Induced Fission of

232

Th

H. Kudo,* Y. Nagame,* H. Nakahara,
I. Kohno, and M. Yanokura

232

NUCLEAR REACTION

Th (p, f); angular distribution,

excitation function two-mode hypothesis, K~, BCS model,[ angular anisotropy.

The angular distributions of fission fragments were measured in the 15 MeV proton-induced fission of 232 Th.
The details of the experimental procedure have already been reported.!) Angular anisotropies obtained forvarious masses are shown in Fig. 1. From this figure, it was found that the angular anisotropy is dependent
on the fission fragment mass: the angular anisotropies of symmetrically divided fission fragments are smaller
than those of asymmetrically divided fission fragments. Therefore, the mechanism of symmetric mass
division is expected to be different from that of asymmetric mass division.

I

I

I

I

14'CelI

J 143Ce

1.4-'"Cs " Sr

'"I
99

Mo

-

1 £

2

-

Sr
Q

91

2 Q

o 1.2r

1

r

Q 97Zr-

IISCd
1. 1 if[\.. "2Pd

-

El!=l

o

-~ 1.0~;J;

1os Ru

r

-

<{

1.0

_l

I

1.1

1.2

I

I

I

1.3
1.4
1.5
Mass ratio ( AH / A'-)

I

I

I

1.6

1.7

1.8

Fig. 1. Anisotropy in angular distributionsof fission fragments from 15 MeV
proton-induced fission of 232 Th vs mass
ratio (mass of heavy fragment divided
by mass of complementary light fragment).

In order to interpret the observed anisotropies, it is necessary to know the amount of contribution fromeach multiple chance fission, namely, (p, f), (p, nf), and (p, 2nf).

For this purpose detailed excitations functionsof fission products and neutron evaporation products were measured in the proton energy range of 8 "' 22 MeV.
It was found that the excitation functions of symmetrically divided fission fragments were apparently different

from those of a-symmetrically divided ones. This difference is shown in Fig. 2 as the ratio of the cross section of591
ll Cd to that of
Sr. The excitation function of (p, xn) reactions and fission products are plotted in Fig. 3.
Both the anisotropy data and the excitation functions of fission fragments strongly suggest that asymmetricfission and symmetric fission proceed through different saddles .
two-mode hypothesis was introduced.

Therefore, for interpretation of these results,

In the two-mode hypothesis the existence of two independent types offission is assumed. For interpretation of the observed excitation functions the cross sections of the statisticalevaporation and fission were calculated using the Alice code 2 ) which was modified by us to include thesymmetric and asymmetric fission barriers and sub-barrier penetration terms. The results of this calculation are
shown in Figs. 2 and 3 by solid lines, and used parameters and deduced quantities are tabulated in Table 1.
The fission barrier heights for the asymmetric fission used in the calculation to give the best fit to the observed
excitation functions are in good agreement with other reported data 3 ) and those for the symmetric fission are*Tokyo Metropolitan University.

41

Fig. 2.

Cross section ratio of 115 Cd to 91 Sr. Solidline is calculated with modified Alice code assuming
the yield of 115 Cd in symmetric fission mode andthe yield of 91 Sr in asymmetric fission mode areconstant in this energy region.

EP ( MeV)

+-'

u

(1)
(f)

~

0

u

Fig. 3. Excitation functions ofneutron evaporation products andfission. o: total fission;e : 232Th(p, n)232Pa; .&.: 232Th (p, 2 n)
231Pa; ,0,.: 232Th(p, 3n)230Pa;
D:

reaction cross section which was

assumed to be the sum of crosssections of fission and evaporation
process.

Solid lines are the resultof calculation with modified Alicecode .

20
E p ( MeV)very close to the value for 232 Th predicted theoretically by Moller and Nix. 4 ) From this statistical calculation,
the amount of contribution from each multiple chance fission and the effective excitation energies at thesaddle points could be deduced as shown in Table 1.
The angular anisotropy of fission fragments is , according to Bohr's channel theory, related to the Kquantum number of the saddle point configuration and given by the following equation at rather high excitationenergies s) :1 2 sin 2 {}(2] + 1) 2 T exp { - ( J + 2)

W(()) oc

I 4K2} 1 {i

1 2 sin{}2 / 4K ') }(] + 2)0
L ------------------------------------------------ , ( 1 )1

J=O

erf { ( J +t) / ( 6)2K

001I 2 }

42

Table 1.

Used parameters and deduced quantities in the calculation of proton-induced fission of232

Th with modified Alice code .
Bf is fission barrier height; af and an are level density parameter at saddle point and groundstate, respectively, and an was taken to be A/8 (Mevr 1 (A= mass number of fissioning
nucleus). E is excitation energy at saddle point and t is nuclear temperature at saddle
expoint.
t (MeV)*Bf (MeV)fissionSymmetric

p

6.2
6.0
8.8

{ (p, f)(p, nf)fission
At E

5.9{ (p, t)(p, nf)(p, 2nf)

Asymmetric

8.7

1.02

1.15

Contribution to eachmode of fission*

14.3

0.69

0.39

7.5

0.50

2.1

0.27

0.05
0.56

11.4

0.58

0.98

5.0

0.39

0.02

15 MeV.

where J 0 is the :z;eroth order Bessel function and erf(X) is the error function. K~ is given by t·/eff/h2 , where t isnuclear temperature and Jeff is effective moment of inertia which is defined by

1
I eff

1

1

I j_

where / 1 and 111 are the moments of inertia around the axses perpendicular and parallel to the nuclear symmetryaxis, respectively . J and TJ are the total angular momentum and the transmission coefficient, respectively.
However, for the nuclei of low excitation energy , the effect of nuclear pairing has to be taken into
consideration (BCS model) 6 ) and the ordinary statistical argument of K~ has to be modified accordingly.
The moment of inertia of the nuclear superconductor is considerably smaller than that of rigid body?). In the
BCS model, K~ is given by
2
K0 =

I _t
I j_ - A{t) IJigid

·

rigid
tc 111n2·t·A(t)( 2)

where !fgid is the rigid body moment of inertia with respect to the symmetry axis, tc is the critical temperature,
tis nuclear temperature in unit oftc, and A(t) is the temperature-dependent integral. In the 15 MeV
proton-induced fission of 232 Th, the excitation energy for the asymmetric third chance fission is expected to be
only 2.1 MeV at the saddle point. Therefore, the pairing effect should be taken into account in the interpretationof the data.

In the present case, tc and A(t) is estimated to be 0.431 and 0.336 MeV, respectively, for thefissioning nucleus 231 Pa from Ref. 7.
Using the results of calculation on the evaporation-fission competition including the two-mode hypothesis
and Eqns. (1) and {2), angular anisotropy of the present system can be deduced theoretically. The result istabulated in Table 2 together with the values of A(t), J1 rigid, I/igid and K~. The angular anisotropies
obtained are in good agreement with the observed data for the fragments produced by typical asymmetricand symmetric mass divisions ( 92 Sr, 141 Ce, 147 Nd, etc . for typical asymmetric mass division, used, 112 Pd for
typical symmetric mass division). The angular distributions of the fragments intermediate in the mass division
can be considered to be mixtures of the angular distributions of asymmetric and symmetric fission modes.
It is concluded that, with the assumption of two saddle point configurations, one for symmetric fission andthe other for asymmetric fission , the observed angular distributions of fission fragments could be reproduced

.43

reasonably well. Therefore, it is suggested that the gross feature of the final mass division in fission process
is already determined at saddle point configuration through which the nuclear collective motion would proceed.

Table 2.

AsymmetricfissionSymmetric
fission

Theoretically predicted angular anisotropies in the 15 MeV proton-induced
fission of 232 Th.

{ (p, f)(p, nf)(p, 2nf){ (p, f)(p, nf)A(t)frigid

1

1.90

1
0.336

1

frigidIIK20

W(0°)/W(90°) { W(Oo)/W(90o)} sum

0.5675

71

1.05

1.89

0.5695

51

1.07

1.88

0.5710

7

1.50

1.90

0.5675

59

1.06

1.89

0.5695

40

1.08

1.30

1.06

References
1)

H. Kudo, H. Muramatsu, H. Nakahara, K. Miyano, I. Kohno, and M. Yanokura: IPCR Cyclotron Progr.
Rep., _!l, 24 (1979).

2)

F. Plasil: ORNL Report, TM-6054 (1977).

3)

B. B. Back, H. C. Britt, 0. Hansen, B. Leoux, and J.D. Garrett: Phys. Rev. C, ~ 1948 (1974);
R. Vandenbosch and G. T. Seaborg: Phys. Rev., 110, 507 (1958).

4)

P. Moller and J. R. Nix: Nucl. Phys., A229, 269 (1974).

5)

J. A. Wheeler: "Fast Neutron Physics", Wiley (Interscience ), New York, Pt. II, p. 2051 (1963).

6)

R. Vandenbosch, H. Warhanek, and J. R. Huizenga: Phys. Rev., 124, 846 (1961).
J. J. Griffin: ibid., 132, 2204 (1963).

7)

44

4-11.

Friction Tensors for Ar +Au and Cu + Au

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

NUCLEAR REACTIONS Microscopic calculation of friction tensors
for the systems Ar + Cu and Cu + Au: linear response theory:[ two-center shell model.

l

In Ref. 1 we have applied the linear response theory to the calculation of friction tensors for the system
Ne + Al. In this calculation, use of the two-center shell model for the basic Hamiltonian was found to have apromissing feature, namely, it could give us values of friction tensors systematically even for a very complicatedconfiguration encountered in the heavy-ion reaction. These values were used later 2 ) in the equation-of-motion
calculation and typical features of deep-inelastic collision were reproduced well. Although many works have been
done for the microscopic calculation of friction tensors, there are only a few works which have calculated form
factors properly. Thus we think it is useful to apply our model to heavier systems and analyze form factors offriction tensors.
In the calculation presented here, we changed the method of "subtraction" described in Ref. 1. This isbecause we intended to obtain friction tensors at surface region as accurate as possible. Another new point isthat we included a new collective coordinate 'r/, which describe the mass flow between two nuclei. As a result,
we could also calculate friction tensors resulting from particle transfer.
We start from the expression of friction tensors given by linear response theory,

4 1r r 2::1 ik

r 1-l'-'

c e k - e J. ) < i I F I k >< k I F I i >
1-l

{(e
.

k

1.1

(1)

- e .)z+ r z } z
J

where

I. =

(2)

Jk

~

Symbols used in these expressions are the same as in Ref. 1 and FfJ. stands for the generalized force
corresponding to the coordinate fJ.. Single-particle energy e . and wave function I j > are generated by theJtwo-center Hamiltonian.

As collective coordinates, we choose three kinds of coordinates: the distance R
between two nuclei, the deformation f> of two nuclei (for simplicity, we assume the same deformation forboth nuclei) and 'r/ which is given by 'r/ = (A 1 - A2 ) I (A 1 + A2 ) where A 1 and A are mass numbers of the two2
nuclei.
As was discussed in Ref. 1, there occurs a spurious term in Eqn. (1) when we calculate "f HR, "f 1 ~, and "f R1J
It is connected to spurious excitation arising from the translational motion of each nucleus. In order toeliminate this contribution, we proceed as follows: when two nuclei are located with their surfaces touchingeach other or they are only a little distance apart (friction tensors for such configurations are most important andwe concentrate ourselves to these configurations), we can classify the single-particle wave function according towhether it is localized to nucleus 1 or to 2. Correspondingly, matrix element <kIF P li > appearing in
Eqn. (1) is classified into three kinds: one where wave functions li > and < k I are localized to nucleus 1, one
where I i> and <k I are localized to nucleus 2 and one where IJ> and <k I are localized to different nuclei.
Physically, the third one is related to particle transfer between two nuclei. We neglect it because the operator* Japan Atomic Energy Research Institute.

45

3

Ar + Au

Cu+ Auo = O.O
T = 1.5 MeV

"'I

E 2

o=O. O
T= 1.5 MeV

N

I

E

u

Bl

><l.l

><l.l

L

L

I

0

,..----<

R

Fig. 1.

R(fm )Friction tensors 'Y RR as a function of center separation R.

(fm )Dashed lines are thecontributions from heavy nucleus, the dot-and-dash lines are those from light nucleus andthe solid lines are their sums. a) for Ar + Au system, b) for Cu + Au system .

FR has nothing to do with such process. Rather , the contribution from such process is accounted for bytaking account of the 17-motion in our model. The "subtraction" is carried out in our model in such a mannerthat the matrix element of the first kind is calculated in the rest frame of nucleus 1 and the matrix element of
the second kind in the rest frame of nucleus 2. In this way , we calculate the excitation of nucleus 1 by theproximity of nucleus 2 and vice versa. In the calculation of friction tensors corresponding to 17-motion, we
adopt a similar method of subtraction . That is, we neglect the matrix element of the first and the second
kinds and include only the third one. The details of this method will be published elsewhere .
In Fig. 1, we show the radial friction 'Y R R calculated for systems Ar + Au and Cu + Au as function ofcenter separation R . A contribution from heavy nucleus (Au) is shown by dashed lines , that from light nucleus

6
5

Cu+ AuAr + Au

u

u<l.l
(f)

o=O.O
T= 1. 5 MeV><l.l 4L"'I
0,..----<&l><l.lo= O.O
T= 1.5 MeV

L
I

0

3

,..----<,.

,..._,.,.

~

2

R ( f m)R ( f m)as a function

Fig. 2.

Friction tensors 'Y

system,b) for Cu + Au system.

1717

of center separation R.

a) for Ar + Au

46(Ar, Cu) by dot-and-dash lines. We find that the contribution from heavy nucleus occupies the dominant part of
the radial friction. It means that the intrinsic excitation of heavy nucleus is much larger than that of lightnucleus. It seems that relative single-particle level densities near Fermi level plays an predominant role toallocate excitation energy to two nuclei. Comparing Fig. 1 (a) and 1 (b), we find that the absolute value of radial
friction 'Y RR is not very different for the two systems. Main difference is that effective diffuseness of 'Y RR
for Cu + Au is larger than that for Ar + Au. When we compare our results with that of proximity friction of
Ref. 3, we find that, for Cu + Au system, they are very similar both in absolute value and in form factor.
For Ar + Au system , however, our results have longer effective radius and shorter diffuseness. Although notshown in this figure, the radial friction calculated with the method of Ref. 1 are not very different from thepresent results. A difference is that the former has a little longer range.
In Fig. 2 we show the friction tensor 'Y TIT/ ·for Ar + Au and Cu + Au systems. This is the firstmicroscopic calculation of friction form factors corresponding to the mass flow between two nuclei. Just as
was for 'Y RR, the absolute values of 'Y T/T/ are nearly the same for both system. A difference in the behavior isthat 'Y TIT/ has a surface-peaked form factors for both systems, while 'Y RR shows rather volume type form factors.
The range of 'Y TIT/ is longer than that of 'Y RR. Discussion on these points, together with that of the relation
among 'Y RR, 'Y TIT/, and 'Y R7l will be presented in the forthcoming paper.

References
1)
2)
3)

K. Sato, A. Iwamoto, K. Harada, S. Yamaji, and S. Yoshida: Z. Physik, A288, 383 (1978).
K. Sato, S. Yamaji, K. Harada, and S. Yoshida: ibid., A290, 149 (1979).
J. Randrup: Ann. Phys., (N.Y.), .!._!l, 356 (1978).

47

4-12.

Numerical

Analysis of the

63

Cu +

197

Au Reaction Basedon the linear Response Theory

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

NUCLEAR REACTIONS Analysis for the 63 Cu + 197 Au reaction;
linear response theory; two-center shell model.

J

On the basis of the linear response theory, 1) a microscopic calculation of friction tensors 'YJlV (Jl, v = R, 8, 77)
was performed for the systems 40 Ar + 197 Au and 63 Cu + 197 Au, 2) using the two center model. The linear response
theory seems to be more properly applied to those systems than to a light system such as 20Ne + 28 Si. 3) The
distance R between the two nuclei, the deformation 8 of each nucleus and the mass asymmetry 17 were taken
as the collective variables in Ref. 2.
Neglecting the 17-motion, we have solved the equations of motion with the calculated frictions for the reaction
63
Cu + 197 Au with full coupling terms, in which statistical fluctuations are also included. The mass tensors m v
11in the equations of motion were approximated with hydrodynamical ones obtained by use of the Werner-Wheeler
method. Yukawa-plus-exponential potential was taken as the nuclear potential in the same way as in Ref. 3.
In the present calculation, the cS-motion is assumed to start when R reaches the distance of closest approach or
the touching distance R 1 + R , where R and R are radii of the two nuclei. The potential for later process was2
12
calculated including the effects of the neck-formation and of the charge equilibration.
In addition to the radial.frictional force, tangential force F t and rolling force F r written in the form of
Fl =-CrrRR: (R I (R1 + R2) ) 2 X (Rl (01- eo)+ R2 (02- eo)) and Fr =-Cr'YRR (R I (Rl + R2)) (01- e),re~pecti;ely,- were included in the equations of motion, where 8 is the polar coordinate between the centers0of two nuclei and 8 1 and 8 are the angles specifying the orientation of the two nuclei.
2
As the value of the parameter Ct, we took two values, 0.5 and 1.0. The former corresponds to the_p roximity friction 4 ) and the latter to Tsang's friction. s)
In "(-multiplicity (M'Y) measurement on 365 MeV 63 Cu + 197 Au reaction, a large amount of angularmomentum transfer was observed in the quasi-fission process, but the evidence for a sticking behavior was notdemonstrated because M'Y did not depend on mass asymmetry in the sticking case. 6 )However, since our treatment is based on the axial symmetric two-center shell model, the system mustpossess the symmetric axis throughout the collision. Therefore, in spite of the incomplete achievement of the
sticking condition, we require in our preliminary calculation that the sticking condition has been achieved
when the deforming motion starts. In the calculation of the reaction 63 Cu + 197 Au with Elab = 365 MeV andf = 55 h, the coefficient Cr was taken as a parameter (zero corresponds to rolling). In Fig. 1, the quantities
R, cS, 8 1 - 8 0 , 8 2 - 8 and 6.£ for the case of Cr = 20.0 are shown as a function of time t, where 6_.f. is the angular0momentum transfer. It can be seen that 8 - 8 and 8 - 8 are very small and that the calculated angular0120momentum transfer 6.f is nearly equal to 6.fst = 22h estimated by the relation in the sticking limit t::.f.St =£(1 1 + I 2) I (I 1 + I 2 + Ir), where I and 1 are the moments of inertias of the projectile and target nuclei and12
Ir = 11(R 1 + R 2) 2 , J.1 being the reduced mass. Therefore, Fig. 1 shows that the sticking motion is realized in
the calculation for cr = 20.0.
The result for the reaction 63 Cu + 197 Au with Elab = 365 MeV is given in Fig. 2, which shows the deflection
angle 8, its second moment x88 , maximum deformation omax and energy loss E* as a function of the initial
angular momentum f.
The appreciable difference appears only in the quantity x between the two cases, Ct = 0.5 and Ct = 1.0,88which are plotted by the solid and dashed curves, respectively. However, this difference does not affect much*

Japan Atomic Energy Research Institute.

48

25

63

Cu + 197 Au

E1ab = 365 MeV

20

L =551'1

.E
15
10
0.4
0.3
0.2
0.1
0.0
10
0.0
Q)
0
-o
-10

Fig. I . The radial motion R, deforming motion 8,
differences of angles 8 1 - 8 0 , 8 2 - 8 0 and angularmomentum transfer b. Pas a function of time t for thereaction 63 Cu + 197Au with E lab = 365 MeV and
P (initial angular momentum) = 55 h. The time t is set
equal to zero at R = 26 fm. The quantities 8 1 - 8 2
Lll

30_:::; 20
100

200

300

400

500

t (1 o-23 sec )and 8 2 - 8 0 are normalized to zero at o = 0.01.
The coeffiCient of the rolling friction Cr is taken to be
20 .0. The quantities for Ct = 0.5 are shown, because
the calculation of these quantities for Ct = 0.5 and 1.0
give nearly the same values.

63Cu+ 197 Au
Elab=365MeV()

C t =0.5---- C t =l.O

60
50
40

"'·0.0 30
Q)-oFig. 2. The deflection angle 8, its second
moment x88 , maximum value of thedeformation Dmax and energy loss E* as afunction of the initial angular momentum
P for the reaction 63 Cu + 197 Au with E lab= 365 MeV. The solid and dashed curves
for 8 and x88 correspond to the cases of Ct= 0.5 and Ct = 1.0, respectively. The

20
10

0
0.6
0.4
0.2
0.0
>Q)
2:

50

quantities omax and E* are shown only for
C t = 0.5 , since there is not an appreciable
difference between these quantities for C t= 0.5 and ct = 1.0.

050
L (n )

49

63Cu+ 197 Au
E ,ab=365 MeV

400•---• EX P
I

I

I
I
\
I

I

-o
cu

I
•

:2J 300

I

E
\

E

\

:g 200

\

\
\

8""tl

\

\

" /

l

/

I

I

I

Ct = l.O

I

~

\

\

\

\

\

•\
\

100

0

--CAL
Ct =0.5
CAL

r•,

I

\

.,

" .......

-.......

30
Bc. m ( deg.)

Fig. 3. Calculated angular distribution for thequasi-fission compared with the experimental
result. The solid and dashed curves correspondto those calculated for the cases C t = 0.5 andct = 1.0, respectively.

on the cross section (see Fig. 3).

It can be seen that the degree of freedom of the deformation plays an important role to explain the large
energy loss in this heavy system 63 Cu + 197 Au as well as in the light system. 3) The experimental energy lossof about 80 MeV was well reproduced by the calculation including the energy loss due to the deforming motion
whose magnitude is 35 MeV for £:S: 75 h.
The cross section for the quasi-fission process can be obtained by integrating the Gaussian distributionfunction whose center is 8 and whose width is Xee over the angular momentum£ from 0 to 75 h. The calculated
result is compared with the experimental one?) in Fig. 3. The cross sections for Ct = 0.5 and Ct = 1.0 shownby the solid and dashed curves, respectively, are very similar to each other and the small difference between them
was found to occur not from the difference between the second moments Xee for both cases but from thedifference between the deflection angles 8 for both cases. The orbits with the deformation degree of freedom
stay longer in the region of internal attractive potential and are deflected more than those without deformation
degree of freedom .

Therefore, the fit to the experimental angular distribution becomes worse , as the peak

position of the calculated cross section is shifted to the forward angle with the inclusion of the deformation
degree of freedom. For the convenience of the calculation , the sticking motion was realized by using a large
value of the rolling friction coefficient Cr. On the other hand, two nuclei do not completely stick as was
revealed experimentally 6 ) but roll together. This rolling motion between two nuclei may suppress the evolutionof the deformation, which yields a short collision time and large deflection angle. Therefore , the peak positionof the calculated cross section will be shifted to backward angle and the fitting will be improved.

References
1)
2)
3)
4)
5)

H. Hofmann and P. J. Siemens: Nucl. Phys., A275, 464 (1977).
A. Iwamoto, S. Yamaji, K. Harada, and S. Yoshida: IPCR Cyclotron Progr. Rep. , !±, 44 (1980).
K. Sato, S. Yamaji, K. Harada, and S. Yoshida: Z. Physik, A290, 149 (1979).
J. Randrup: Annals of Physics, !._!l, 356 (1977).
C. F. Tsang: Physica Scripta. , 1OA , 90 (1974).

6)

M. Lefort and C. Ng6 : Ann. Phys. , ~ 5 (1978) .
C. Ng6 and H. Hofmann: Z. Physik, A282, 83 (1977).

7)

50

Semiclassical Treatment of the Direct Reactions

4-13.

Induced by Heavy Ions II

T. Kammuri and K. Matsuoka*

NUCLEAR REACTIONS Heavy-ion reactions; semiclassical theory of( one-and two-step transfer; energy spectra and polarizations

J

On the basis of the semiclassical theory of transfer reactions between heavy ions one can write the transfer
form factor so as to show explicitly the effects of matching the linear and angular momenta before and after thetransfer on the cross sections.l) In that paper we approximated the trajectory of relative motion to be astraight line ) as was done by Brink. 2 )Here we add formulas for the case in which two ions form a di-nuclear system temporarily. The incident
ion is assumed to rotate around the target nucleus with an angular velocity n for a time interval T. The form
factor of the one-particle transfer process is given by(1)

and the transition amplitude is
(2)

where
1

C C )(l9) = sin l9/l9, l9 = ¢6L /2, ¢=Or.

(3)

We follow the notations of Ref. 1, in which 6k and 6L are the differences of the linear and angular momenta
between the final and initial states respectively. The amplitude of the sequential transfer process becomes(1)

C · f = CH

- 22
0 N. x ex p
I 2 ) ( i l'i.) i=l1c (2 ), l9

l9

. 2

( 2)
1

\.

1'

2

) = {c ( l)(l9.

1{- ( R 6 k ·I a . )
1

2}

11

+ l9) - eil9tc (l) ( l922C(2 ) ()} / l9)

l91' l9 2 '
1

(4)
(5)

The differential cross sections of the one-and two-step transfer reactions are given by(6 a)( 6 b)
cross
scatteringrespectively. Here a(i.) ' s (i=l , 2) in the right hand side are given by the product of the elastic
2 and Pn(E*, £ ) is the level density of the n-particle excitation of the final nucleus withsection with I c(i) 1 ,2
the excitation energy E* and spin £ 2
Pn ( E * ,.e 2 ) =p 0 ( 2 .e 2 + 1 ) e x p ( - .e 22 I 2 I T ) ( E * ) n.- 1* Osaka Institute of Technology.

(7)

51

0

s3Cr ( '4N, '3C)s4Mn
E 1ab = 120MeV
Blab = 20o

E 1ab = 90MeV

Blab= 16o
VN=28

T=6
~
c
ro

_c

u

'-...
(f)

c

::J

0

u
0

0

0

0.1
40

50

60 70 80£lab (MeV )

90

100

Fig. 1.
Energy spectrum of Be emitted
53
from the er( 14 N, Be) reaction at 90

Fig. 2.
Energy spectra of 16 0 and 12 eemitted from the 27 Al( 20 Ne, 16 0) and

MeV incident energy.

27

Al( 20 Ne, 12 e ) at 120 MeV incident
energy, respectively.

/-,)'-0-<

1--0-Y
I
I

I

I>--0--<I

I

I

1oo Mo ( 14N, 12B )E 1ab = 90MeV

Blab = 20o
50

\

\

''

-50

''

'

\

Circular orbit--one-step
VN= 28, T= 5,8 = 0. 7
- --- two - step
VN=O, T= 5, 8= 0.4- 1 00L---~--~---6~0~~~--~--~£lab( 128 ) (MeV )Fig. 3.
Energy spectrum and polarization
12of B from the 100 Mo( 14 N, 12 B ) at 90
MeV incident energy.

52Here the one-particle level density is assumed to be independent of E*, and I is the moment of inertia of therelative motion between the cluster n and the core, and T is a parameter corresponding to the nuclear
temperature. For small T the strong spin dependence of the level density shifts the peak of the energy spectrum
2
to lower E* as compared with that given by the matching condition.1), ) The width becomes smaller
correspondingly.
We firstly compare experimental results with the calculations done with the straight line trajectory. Figure 1
3
53
14
shows the energy spectrum of 13 C from the 90 MeV N + Cr reaction. ) Here Tis taken to be 6 MeV and the4strength of the nuclear potential VN equal to 28 Me V ) is included in calculating the kinetic energies. Most of thecalculated spectra of one-particle transfer reactions do not tend to zero for zero E*. Figure 2 compares27
experimental 16 0 and 12 C spectra from the 120 MeV 20 Ne + AI reaction with calculations done by assuming
a: and 2a: sequential transfers, respectively. We took T equal to 20 MeV and VN was chosen to be 10 MeV.
16
Solid curve in the 16 0 spectrum shows cross sections summed over the transitions leading to three 0 states16
having large spectroscopic factors for 20 Ne g.s. -+ 16 0 + a:, while in the dashed curve only the 0 ground state is
12
taken into account. We neglected the processes that populate excited states of C as in Ref. 6.
4
12100
Moct N, B) reaction at 90 MeV incident energy
The energy spectrum and polarization of 12 B in the
7were analyzed by assuming the simultaneous transfer of two nucleons and the straight line trajectory. ) Fit to theexperimental polarization was good only at low E * region. In Fig. 3. results of one-and two-step calculations
under the assumption of the circular orbit are shown in solid and dashed curves, respectively. Values of(T, VN, ¢)in units of (MeV, MeV rad.) are (5, 28, 0.7) and (5, 0, 0.4) for one-and two-step calculations,
respectively. Although there is a big difference in the adopted values of VN, both calculations give equally
good fit to the experimental results. Thus it is difficult to draw difinite conclusions on the relative importance ofthe one-and two-step processes from the comparison of the theory with the experimental energy spectra andpolarizations.

References

4)
5)

T. Kammuri, K. Matsuoka, and M. Sano: IPCR Cyclotron Progr. Rep., .!l_, 39 (1979).
D. M. Brink: Phys. Lett., 40B, 37 (1972).
T. Mikumo, I. Kohno, K. Katori, T. Motobayashi, S. Nakajima, M. Yoshie, and H. Kamitsubo: Phys.
Rev. C, 14, 1458 (1976);
M. Yoshie and I. Kohno: Sci. Papers I.P.C.R., 69, 63 (1975).
P. J. Siemens, J.P. Bondorf, D. H. E. Gross, and F. Dickmann: Phys. Lett., 36B, 24 (1971).
J. B. Natowitz, M. N. Namboodiri, R. Eggers, P. Gonthier,K. Geoffroy, R. Hanus, C. Towsley, and K.

6)
7)

Das: Nucl. Phys., A277, 477 (1977).
T. Udagawa, T. Tamura, and B. T. Kim: Phys. Lett., 82B, 349 (1979).
M. Ishihara, K. Tanaka, T. Kammuri, K. Matsuoka, and M. Sarro: ibid., 73B, 281 (1978).

1)
2)
3)

53

4-14.

Proton Inelastic Scattering to the( 1 + , T = 1 ; 1 5. 1 Me Y)

S tote

1

n

12

C

M. Sano,* K. Yoro,** and T. Takemasa

NUCLEAR REACTIONS

12

C(p, p') 12 C, E = 45.5 and 155 MeV, 1+ inelastic[ scattering, RPA calculation, DWBA analysis, pion condensate phase.

J

The problem of a pion condensate phase in atomic nuclei and nuclear matter is one of recent interest in
nuclear physics. 1> In particular, the possible appearence of precritical effect of the pion condensation in ordinary
nuclei has been discussed in connection with excitations of low-lying particle-hole unnatural-parity states byinelastic electron 2 > and proton scatterings. 3), 4) If a nucleus is close to the threshold of the pion condensation, one
may expect an enhancement of the differential cross sections at scattering angles corresponding to momentum
transfer of 2- 3mrr. We have carried out analysis for the experimental data of (p, p') reactions to the 1+ statein 12 C with respect to implications of precritical phenomena near pion condensation thresholds.
The nuclear interaction leading to pion condensation may be given by 4 >V (q) =

2) ( a: · Q;2 ·q -;-'" ~ ) ~ . ~q +mk- ga a- 1
f2 ( G
q )
4 7r

E (

2

1

2

,:;._, 1( 1).._, 2where f 2 is the pion-nucleon vertex factor and e(q) is a momentum-dependent polarization denominator associatedwith the virtual excitation of isobar-hole. The first term in the parenthesis is the free-pion exchangeinteraction, and the second term the Landau-Migdal interaction with a parameter g'.
The equation in the random phase approximation (RPA) with interaction (1) was solved for the 1+ and 2states, taking into account of six single particle states: Os 112 , Op 312 , Op 112 , Od 512 , ls 112 , and Od 312 . The
excitation energies calculated for various values of g' are presented in Table 1, and compared with the experimental

Table 1.

Excitation energies of non-normal parity states in 12 C.
Jrr=1 +, T=1

Jrr=1 +, T=O

Jrr=2-, T=1

g'

Ex (MeV)

Ex (MeV)

Ex (MeV)

0.4

14.88

12.83

16.90

0.5

15.27

12.98

17.16

0.6

15.61

13.09

17.38

0.7

15.89

13.19

17.57

17.74
13.26
16.13
0.8
--- ---- ---------------- -·----------------------- ----- ----- -------------- --------------- -- ---- ------------------------E0
11.77
11.77
15.62
., .... J?~---·······- · ····-···------- - -- -- --------- - --- -- - ------ -- ---------- - -- - --- - ---------------------------- - ------·
16.57
12.71
15.11

*

Institute of Nuclear Study, University of Tokyo.

* * Department of Physics, Osaka University.

54

A good agreement with the experiment is obtained for g' value of 0.4 to 0.8. However it should be
noted that the results depend on the size of the configuration space and also on the values of unperturbed

values.

particle-hole energies.
In DWBA calcu,lations, we took the general form for the interaction responsible for the inelastic scattering:- 1
V(Q) = c'(Q)

X

s

"
12

(

q )

}L

~

~

I •

L

2

(2)

'

where S 12 is the tensor operator. The denominator €'( q) is constructed from considerations of virtual intermediate
isobar-hole and nucleon-hole excitations and is given by(3)
Here UN(q) and U t.(q) are nucleon and isobar Lindhard functions, respectively. 4 > The interaction strength a and{3 are determined so as to fit the experimental cross section. The form factor is calculated using the RP A wave
function in the 3hw subspace.
The solid line in Fig. 1 shows the calculated result at Ep = 155 MeV with g' = 0.8, a= 0.4, and {3 = 0.3.

i.o

2.0
I2C ( p.p' )tzC ( p.p')

Ep = 155MeV
1 +, T= 1

Ep = 45.5MeV

Ex = 15.1MeV

Ex = 15.1MeV

1+, T= 1

w-2

w-2

Bc.m. ( deg )Bc.m. (deg )Differential cross sections forDifferential cross sections for15.11 MeV transition in 12 C at EP =15 5 MeV. The solid curve corresponds
to the theoretical prediction obtained

Fig. 2.

with g' = 0.8, a = 0.4, and /3 = 0.3.
dotted curve shows the calculated

g' = 0.8, a = 0.5, and {3 = 0.3. The
dotted line shows the calculated result

Fig. l.

result of Buenerd. 5 )The

15 . 11 MeV transition in 12 C at EP =45.5 MeV. The solid curve corresponds
to the theoretical prediction obtained withof Love and Parish. 6 )55

The optical parameters are the same as those used in Ref. 5. It is seen that the calculation taking account of thenonnucleonic degrees of freedom correctly predicts the enhancement of the cross sections at q '" 2.5 m1T(0 em '""' 40°). This effect is attributed mainly to renormalization of the effective interaction; that is, the inverse of
Eqn. (3) e'(qf 1 has a bump at q ,_ (2 - 3)m1T' and this leads to an enhancement in the cross section. For the sake5of comparison, we present the result of the DWBA calculation performed by Buenerd ) using the usual two-bodyinteraction without the core polarization due to the isobar-hole and nucleon-hole excitations (dotted line in Fig. 1).
As is seen, this conventional calculation reproduces well the data out to q '""' 1.5 m1T (0 em ,...., 25°), but fails to
reproduce the peak at q ,...., 2.5 m1T.
Figure 2 presents the DWBA cross sections at Ep = 45.5 MeV with g' = 0.8, ~ = 0.5, and (3 = 0.3 (solid line),6
and the dotted line gives the conventional calculation performed by Love and Parish ) without the core polarization.
Experimentally, the sharp maximum of the differential cross section at 0 em,...., 80 - 90° corresponding to momentum
transfer near the critical momentum for the pion condensation is not observed at 45.5 MeV. We see that theresult reproduces fairly well the dependence of the second maximum of the cross section on incident energy.
This indicates that disappearance of the second maximum of the cross section in low energy scattering is due tothe effect of distortion on incoming and outgoing waves.

References
1)
2)
3)
4)
5)
6)

A. B. Migdal: Rev. Mod. Phys., 50, 107 (1978) and references therein.
J. Delorme, M. Frieson, A. Figureau, and N. Giraud: Phys. Lett., 89B, 327 {1980).
S. A. Fayans, E. E. Saperstein, and S. V. Tolokonnikov: Nucl. Phys., A326, 463 (1979).
H. Toki and W. Weise: Phys. Rev. Lett., 42, 1034 (1979).
M. Buenerd: Phys. Rev. C, _u, 444 {1976).
W. G. Love and L. J. Parish: Nucl. Phys., A157, 625 (1970).

56

4-15.

Perturbation Theory of Mass Transport 1n Nuclear Collision

K. Sato, N. Takigawa,* and S. Yoshidal

NUCLEAR REACTION

Heavy-ion reaction, mass transport coefficients,

J

perturbative expansion, dynamical effect.

Gross features of the mass transport between two colliding heavy ions have been investigated by many
authors. 1) One needs, however, further study to understand various aspects of the mass transport phenomena.
In this respect, microscopic theories are of particular interest.
As an example of the microscopic theories, Randrup has applied the time-dependent perturbation theory
based on the nuclear mean field approximation and formulated the mass transport coefficients in terms of thesingle nucleon transfer matrix elements?) The expected change of the number of particles in nucleus 1 andthe associated dispersion are given by
( 1)

(2 )
Here PH and p 2j are the occupation probabilities of the bound single particle states i in the nucleus 1 and j in
the nucleus 2. The single nucleon transfer matrix element tj--+i in which j--+i means the transfer of a nucleon from
nucleus 2 to 1 is given by Eqns. (2.11) and (2.12) in Ref. 3.

The matrix element ti--+j of a nucleon transferfrom nucleus 1 to 2 is given by similar equations. Expressions (1) and (2), which are fairly simple, have been
derived by disregarding the fact that the mass transport occurs between two nuclei which are in relative motion.
Correspondingly, the transition matrices are estimated in the static approximation.
In treating the nucleon transfer between two nuclei which are in the relative motion, however, we should
evaluate the transition matrix element analogously to finite range DWBA matrix element. 4 )In Ref. 3, we havereported that such a matrix element of nucleon transfer is considerably influenced by the relative motion(Dynamical Effect) . So far, however, it has not yet been clarified whether simple microscopic expressions like Eqns.

(1) and (2) can be still obtained when the transfer matrix elements properly take account of the dynamical effect.
In this report we show that Eqns. (1) and (2) are still valid with a slight modification.
We follow the semi-classical theory of heavy ion reactions proposed by Dietrich and Hara. s)

In the theory,the direct sum of the whole bound single-particle states in nucleus 1 moving on a classical trajectory R(t) and of
those in nucleus 2 at rest is used as a "working space". The creation and the annihilation operators of a
nucleon thus depend on time. The non-orthogonality is taken into account by introducing the dual basis.
According to Ref. 5, the intrinsic states of the colliding nuclei approximately satisfy the following
time-dependent Schrodinger equation:( 3)
Here the operator H0 represents the sum of the intrinsic Hamiltonians of nuclei 1 and 2.

"'

The interaction V

reads as follows if we consider the mass transport only through the single nucleon transfer process:- . I U ext + m R·· ( s)(r - R(s)) + U res+I { ~. I ~. } c + .(t ) -C . (t),
2J 2
li
ll
2J .
* Department of Physics, Tohoku University .

( 4)

57

where ~li is the moving single particle bound state wave function of nucleus 1 and is given by,;p . = ¢. (r - R(t ) ) ei(mBCt)I_ - r(t))
11

11

-

-

'

with

( 5)
and V/li is its adjoint etc.

The terms ulxt and u~xt are the potential due to nucleus 2 acting on a nucleon

in nucleus 1 and the potential due to nucleus 1 on a nucleon in nucleus 2 respectively. The term ures
originates from the non-orthogonality of the basis and does not have simple physical meaning. The interaction
V(t, t) contains both c-numbers and operators i.e. the creation and the annihilation operators. The firstargument t indicates the time dependence of the c-numbers, while the second t refers to the time dependenceof the operators. It is now of particular importance to remark that the derivative gt 'in Eqn. (3) does not
act on the creation and annihilation operators. s)
We can then easily move to the interaction. representation,<P{t )= e

iH 0 (t) t<P ( t ) ,}VI (s, t)= e iH 0 ( t)s VA(. s, t ) e - iH 0 ( t)s '( 6)

and we find the solution of Eqn. (3) in an iterative form,l ( )I<P t >= e - iH 0 Ct)t Texp { -i~ t e iH 0 Ct)s"V(s, t )e -iH o Ct)s
·
ds

0

}I

<jJ

0

(t) >,(7)

where T is the time ordering operator and I ~ 0 > = n C~(t) I 0 >is the Hartree-Fock ground state of the
combined system. It is the solution of Eqn. (3) under no interaction and acceleration. The adjoint stateof

Ic:I>( t) > is given by
-

.A +

.A +

.A+

I<PC t ) > = e - 1H o ( t) t T ex p { - i{ ~ e 1 H o ( t) s V+( s, t) e - 1 H o ( t) s ds} 10 ( t )> ,(8)0

where I VI o> = n c~ (t) I 0 >. The tildes refer to the dual states.
The induced change in the number of particles of nucleus 1 during the time interval t - t 0 should begiven bywhere the argument t 0 in c:I>(t 0 ) means that only the c-number part of c:I>(t) is estimated at the time t 0 , while
the creation and the annihilation operators are defined at t.
We now define the transfer operator T(t) byAA

T ( t ) = ftto e i H o( t ) s V(s, t ) e - i H o ( t ) s d s '(10)

We then divide it into two parts,

T(t) = T(+)(t) + T (-)(t) = >'t . . Ct)C:(t)C .Ct) + I:t .. Ct)C:(t) C. ( t),.

t .. (t) = f
1.1

etc.

~

J1

I

J

1j

J

(11)

1

t
I ext
··
)
s
ds < <P. U+ mR(s)(r-R(s)+ U res [·'·"" 1i > e - i (c.-1 c.)
J
'
to
2 .1
1
-

(12)

58

The first and the second parts of T( t) describe the transfer of a nucleon from the nucleus 1 to 2 and the
opposite process respectively. We note that the nucleon transition matrix element tij ( t) defined by
Eqn. (1 2) is essentially the same as that given by Eqn. (2,4) in Ref. 3 , although the former is based on the
Hartree-Fock theory and the latter on the shell model. The effect of the relative motion is naturally containedin the transition matrix element tij (t). Approximately we replace <l>(t)> andfunctions of the first-order time-dependent perturbation theory . Then we findJJ~(t)> by the normalized wave
( 13)

Similarly the fluctuation in the particle number of nucleus 1 at the time t is given by2
aA ::: < </J ( t )0!{ TA(- ) ( t ) , TA(+)( t )

}I

</J

0

>.

( t)

(14)

If we take t --7=, the Hartree-Fock ground state of the combined system is simply given by the productof the ground state of each nucleus<Po( t ) > = I<P ol(t ) > I<P oz (t) >(15)

Jo c· t )>= IJ; o 1 ct· ) > l:f 02 (t ) >After a little manipulation, we finally arrive at

A - A 0 = 2::t .. t .. n . J 1 IJ

J

I:t .. t. . n . ,J 1 1J(16)I

2

aA =I:t .. t . . n .C l - n .) + I:t .. t .. n.(1 - n. ),
J1 IJ

J

I

JI

IJ

I

(17)

J

where ni and nj are the occupation probabilities of the bound single particle states i in the moving nucleus 1 andj in the nucleus 2 at rest respectively.
Comparing Eqns. (16) and (17) with Eqns. (1) and (2), we see that the simple microscopic expressions of themass transport coefficients first obtained by Randrup in the static approximation still hold with slight modifications
even when mass transport coefficients are extended to properly take into account the dynamical effect. The
dynamical effect manifests itself mainly through the matrix elements of the nucleon transfer. The transition
matrix element ti/t), however, is not equal to the complex conjugate of tji(t) any more in contrast with thestatic case considered by Randrup.
It is desired to study the dynamical effect due to the relative motion between two heavy ions on themass transport coefficients by using Eqns. (16) and (17).

References
1)

D.K. Scott: Theoretical Methods in Medium-Energy and Heavy-Ion Physics. (Ed. K.W. Mcvoy and
W.A. Friedman) , Plenum, p. 3 (1978) and references therein.

2)
3)
4)

J. Randrup: Nucl. Phys., A307 , 319 (1978) .
K. Sato, N. Takigawa, and S. Yoshida: Deuxieme Colloque Franco-Japonais De Physique Nucleaire
Avec Des Ions Lourds, p. 385 (1979).
D.M. Brink : Phys. Lett., 40B, 37 (1972) ; Lectures at the Summer School at Les Houches (1977);

5)

G.F. Bertsch and R. Schaeffer: Nucl. Phys., A277, 509 (1977).
K. Dietrich and K. Hara: ibid., A211, 349 (1973).

59

5. NUCLEAR PHYSICS
Nuclear Spectroscopy and Instrumentation

5-1.

High Spin States

1n

158

Yb

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

NUCLEAR REACTIONS 142 Nde0 Ne, 4n) E= 120 - 150 MeV, 11 coin,
158
Yb deduced levels. Ge(Li) detectors, enriched target.

(

J

This study is one of a series of experiments on high spin states in Yb isotopes. 1 ) The
142
Nde 0 Ne, 4nr)
states in 158 Yb, highly neutron deficient nucleus, have been populated via thereaction. A self-supporting 142 Nd target of isotopically enriched to 98 % was prepared by use of
vacuum evaporation where 142 Nd2 0 3 was reduced by thorium.
Excitation functions in the incident energy range of 120 to 150 MeV were studied. The maincascade [ -rays in yrast band were also observed via the 144 sme 6 0, 2n[) reaction in the energy
range of 80 to 120 MeV. This reaction was used for the cross check of the residual nuclei towhich the emitted [-rays belong. The four fold coincidence spectra of E11 - E12 - t- T have beenmeasured, where E11 and E12 are the [-ray energies, t is the relative time relation between thetwo [-rays, and T shows the time from the bombardment by a natural bunched beam of thecyclotron.
The high spin states in 158 Yb have been studied by Beck et al. 2 ) and states up to 12+
have been reported. Figure 1 shows a [-ray spectrum which is a sum of 4 coincident spectra
gated by the members of the ground state band from the 8+ state. The ')'-rays belonging to
the transitions of 12+-+ 1o+ -+8+ -+6+ -+4+ -+2+ --*0+ are clearly observed in the figure. Besides
these [-rays, 649 and 682 keY [-rays were detected.

The 682 keY [-ray is in coincidence with

2000r--------------- ---------------------- ------------------,

+
0

a:;

1500

c
c

cc

..c

u....._
(f)

)
N

+
N

CX)

cx:i
L.[)
('f)

)
<::t

c::J

r....:

u

""'"

0

r--.

+

<::t

)
~

+
0

0

0
r--.

L.[)

)
N

Channel numberA ')'-ray spectrum which is a sum of 4 spectra obtained by 11 coincidences
gated by the cascade transitions from 1o+ to the ground state.
Fig. 1.

60( 16+)--- ---r-- --- - 4 813
I:649 (30 )I

4 164
682 (39
3 482
733.5 ( 41)2 748697.9 ( 71)2 050
644.1 ( 76 )1406.0570.1(1 00 )835.9
477 1 (1 00 )358.8
358.8 (1 00 )I58 Yb0

High spin excited states in 158 Yb.

Fig. 2.

Z= 70 (Yb )150.------------------------------ .
N=88----4>

I

>Q)

100

L:

0.05

0.1 0
( hw ) 2

Fig. 3.

0.15

0.15

0.20

Moment of inertias of Z = 70 nuclei.

0.20(hw) 2 ( MeV 2 )(MeV 2 )Fig. 4.

Moment of inertias of N = 88 nuclei.

all the ')'-rays of the members of ground state band up to the 12+ state and this is assigned to thetransition of 14+-+ 12+. The 649 ke V ')'-ray is a candidate of 16+ - 14+ transition, however,
the assignment is less certain because of statistics of each coincidence spectrum.
Figure 2 shows the ground state band of 158 Yb and Figs. 3 and 4 show the plots of angularfrequency verses moment of inertia for the Z = 70 isotopes and the N=88 isotones. The nucleus
158 Yb preserves the same tendency of first deep back bending of 160 Yb and 156 Er.

References
1)

A. Hashizume, T. Katou, Y. Tendow, and H. Kumagai: IPCR Cyclotron Progr. Rep.,!..L 69 (1977); A. Hashizume, T. Katou , Y. Tendow, and H. Kumagai: ibid., 11.., 74(1978).
2)

F. A. Beck, E. Bozek, T. Byrski, C. Gehringer, J. C. Merdinger, Y. Schutz, J. Styczen,
and J.P. Viven: Phys. Rev. Lett., 42, 493 (1979).

61

5-2.

Calculation of Widths of Hole Analog States

S. Yoshida* and S. Adachi*

Calculation of hole analog states, 208 Pb(p, d) 207 Pb )( NUCLEAR STRUCTURE

Hole analog states have been observed by neutron pick-up reactions with high energy-resolution. Thesestates are often in continuum energy region and their widths are narrow. We have been working in this problem
and obtained some results in the case of 207 Pb.
The hole analog states are the analog to the proton hole states and their widths result from mixing of the
T< states by the Coulomb interaction. To calculate these widths the most convenient tool is the Green's function( 1)

where w is the excitation energy of the residual nucleus, and a indicates the neutron hole configuration. The
fmal state ~ may be chosen to be a state decaying by emitting a proton.
To evaluate the Green's function, we first solve the Hartree Fock equation. The Hartree Fock Hamiltonian
his diagonalized by using harmonic oscillator basis. The resulting wave functions are all bound. A hole analog
state is expressed as a superposition of configurations of type a and b shown in Fig. 1. The hole analog statewith T> mixes with T< configurations, of which the most important ones are isovector monopole states withconfigurations shown by c in Fig. 1. The configuration space composed of these configurations is explicitly
treated and it is called P-space. If the Hamiltonian His diagonalized using these configurations we obtain
discrete shell model states. To take into account the decay we have to introduce the Q-space which is defmedby 1 - P =Q. The most important configurations in the Q-space are continuum states and more complicated states
which are shown by d and e respectively in Fig. 1. The continuum state must be constructed to be orthogonal
to bound states.

abpFig. 1.

cedQConfigurations used in calculations.

The Green's function is evaluated as,

( 2)
where

1
1
~P = PHP+ PHQ w-QHQ+io QHP - · PHP+ PHQ w - h+ io

QHP.

( 3)

In the above equations, the arrow indicates the approximate form which will be used in the following.
Broadening of the levels comes from decay into the Q-space in the effective Hamiltonian given by Eqn. (3).

* Faculty of Science, Tohoku University.

62

There are two important contributions : one is that from the configuration shown by d in Fig. 1 whose space isdenoted by Qt, while the other is from 2p-3h configuration shown bye in Fig. 1, whose space is called Q-!-.
Therefore the effective Hamiltonian (3) becomes< ai JFpi,B >=< aiHI,B > + J < alhlq > E~Ec:lJ < qlhi,B > dEq
q+

7< a I Ir >
H

w_

(4)

E~ i 0 <r I H I ,B > .
r

In the second term of the right hand side of the above equation H's .are approximated by h's, q denotes
configuration in the Qt space, and p(€q) is the level density.
The matrix of the effective interaction given by Eqn. ( 4) is symmetric and complex so it may bediagonalized by a complex orthogonal transformatio n T:.

1

CT?lp'T- )st = (Es - ~rs) 0 st

( 5)

TT T = 1.
The total width r s is evaluated as

L: T sa < ai ~P I ,8 > T s ,8)
rs = - 2 1rl m ( ap

( 6)

The escape width appears in the Green's function in Q-space in the expression (2) and has the following form:
2:Ta <a lhlq w > 1
r sq t = 27r,o(w)IL
a s

( 7)

In a similar way the spreading width which expresses decay into Q space is given by0< aiHir > 12 - E ) 2 + o2
r s ~ = 2L:IL:T(w
r a sa(8)rwhere 'Y is restricted to 2p -3h configurations.

t+ r s~) I N s 'r s =C L:rq sq

Thus the total width rs is given by

( 9)

where

N

sa
a
s = l::IT

1

2

~ 1.

( 10)

207
Pb analog states are presented. In the calculation we used
In the following, some numerical results for
Skyrme III interaction in solving Hartree Fock problem. When we diagonalize the Hartree Fock Hamiltonian h,2harmonic oscillator wave functions whose size parameter is fixed to 0.1688 fm- are used. The number of basis
which is denoted by Nsp is chosen from numbers between 10 and 20, while the dimension of the Q-space Nph
is chosen from numbers between 44 and 86 which corresponds respectively to &1=2 and 4. In evaluating thematrix elements given by Eqn. (4) the real part of the last two terms of r.h.s. is neglected. The results are shownin Table 1 together with experimental data. The excitation energies Es are measured from the ground state of208
Pb. In the case of Nsp=14 and Nph=44, the level is split into two. As seen from the table, the escape widths

seem to be more or less the same except for the case Nsp =20 and Nph=44, while the spreading widths change
little from case to case. As for the total width in the case of fTT=1/2-, the theoretical value is a little smaller
than experimental values, while in the case of Jrr=11/2- they are of comparable magnitude.

63

Table 1.

J1l"
-

1/2

Comparison between calculated and experimental results for 207 Pb
hole analog state.
rs t (keY)

Nsp

Nph

Es (MeV)

10

44

25.48

40

86

25.40

30

r -1s

rs

Es (Exp)

rs (Exp)26.66

350±6050± 115

14

44

20

44

25.65

221

150

65

25.54

57

160

86

25.51

63

155

44

27.95

86

27.87

230

--------------------------- ---------- ------------- --- ------ --- --- ---- -------- -- -- --- --- -- --- --------------------------------------------------------------------

11/2

20

155

68

29.94

225±40

64

5-3.

A

Double Scattering Proton Polarimeter

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

NUCLEAR INSTRUMENT Proton polarimeter, double scattering method,
second target carbon, second scattering angle 45°; measured and calculated[lanalyzing powttrs.

A double scattering proton polarimeter using a carbon foil as an analyzing target wasconstructed for the purpose of measuring spin polarization of protons emitted in heavy-ion
reactions. These protons often have continuous energy spectra 1 ) and the polarization of suchprotons is considered to be less than about 20 % from our preliminary work. Special care was,therefore, taken of the following points.
1) Possible backgrounds originating from )'-rays, neutrons and electrons must be negligible,
because we cannot subtract them from an observed energy spectrum.
2) It is necessary to distinguish elastic from inelastic scatterings in the analyzer.
3) High analyzing powers are essential to suppress the effect of possible false asymmetry
originating from anisotropic angular distribution of protons and geometrical unbalances of thepolarimeter.
4) Good efficiencies are required, since the yield of protons is not very large.
Figure 1 shows a schematic view of the present polarimeter used for the 93 Nb( 14 N, p)
A 9 mg/cm 2 thick Nb target (T) with a 35 J.Lm Au backing (Au) was
bombarded with 14 N-ions from the cyclotron. T.he backing is thick enough to stop the beam,protecting the .6.E 1 counter from the elastically scattered 14 N-ions. Protons emitted from thereaction at 95 MeV.

target pass through the Au backing, an aluminium energy degrader (D) and the .6.E 1 counter.
Then they are scattered by the carbon analyzer (A) of 34 mg/cm 2 thickness. The scattered

50mm

Schematic view of the present polarimeter. C: Beam
Fig. 1.
collimater, T: Target, Au: Au backing, D: Energy
degrader, S: Entrance slit, .6E 1 : 50mm 2 - 50J.Lm Si detector,
A: Carbon analyzer, lili 2 : 50mm 2 - 50J.Lm Si detector,
E: 50mm 2 - 2000J.Lm Si detector, V: 60J.Lm Si detector.

65

protons are detected and particle-identified by asymmetry counters which are counter telescopes
consisting of 50 J.Lm (6E 2 ) and 2000 J.Lm (E) Si detectors. They are placed at 45° on both sides
with respect to the emitted protons. Yield of protons from the Au backing is less than a few
percents in the case of Nb target.
negligible.

Thus the effect on polarization from these protons isWith the help of the veto counter (V) accidental coincidences between 6E 1 and6E 2 - E detectors were found to be less than 0.1 %. The solid angles of the 6E 1 and theasymmetry counters are 6.7 and 50 msr, respectively. Lead blocks are placed in order toprotect the asymmetry counters from ')'-rays produced in the target.
Pulse heights of the 6E 1 counter work for rough particle-identification and ensure that
incoming particles into the analyzer are really protons, so that we can eliminate reactions occurringin the analyzer. We can also distinguish inelastic from elastic scatterings, because the protonenergies measured with the counter telescopes are quite different from each other for thesame pulse heights of the 6E 1 counter. However, this discrimination becomes difficult for
high-energy protons, limiting the applicable energy range to less than around 20 MeV.

!
i

c

<(

;-J'\

0.0 -

\
-o.5 -

~\T

A

~

I

\

-

~

Q

T~-i--_/~

2-10 ~~--~~--~--~~--~~--~--~~'--~--~

5

10

Ep

15
( MeV )

Fig. 2.

Experimental and calculated

effective analyzing powers of thepresent polarimeter given as a functionof proton energy incident on the
carbon analyzer.

Figure 2 shows effective analyzing powers of the present polarimeter estimated from the
known polarizations and cross sections of proton elastic scatterings with carbon given in theliterature. 2)

They were experimentally checked by measuring the double scattering of proton

beam using a carbon target at various energies available from the cyclotron. Agreement between
experiment and calculation is satisfactory for the present purpose. Since the analyzing powers
are small between 8.5 - 12 MeV, we used energy ranges of 5.5 - 8.5 and 12 - 17 MeV
for the actual analysis. The analyzing powers in these two energy regions are -0.54 and -0.46
on the average with efficiencies of 1.3 and 0. 7 X 1o-s , respectively.

Proton energies incident

on the carbon analyzer could be changed through an energy degrader inserted between thetarget and the 6E 1 counter as shown in Fig. 1.
A measurement of polarization in the case of the 93 Nb + 14 N reaction at 9 5 MeV isreported elsewhere in this progress report.

66

References
1)

2)

T. Nomura, H. Utsunomiya, T. Motobayashi, T. Inamura, and M. Yanokura: Phys. Rev.
Lett., 40, 694 (1978); H. Utsunomiya, T. Nomura, T. Inamura, T. Sugitate, and T. Motobayashi:
Nucl. Phys., A334, 127 (1980).
S. J. Moss and W. Haeberli: ibid., 72,417 (1965); G. E. Terrell, M. F. Jahns, M. R. Kostoff,and E. M. Bernstein: Phys. Rev., 173, 931 (1968);
H. 0. Meyer, W. G. Weitkamp, J. S. Dunham, T. A. Trainor, and M. P. Baker: Nucl. Phys.,A269, 269 (1976).

67

6.

ATOMIC AND SOLID-STATE PHYSICS

6-1.

X-Rays Following Multiple Inner-Shell Ionization (5)Y. Awaya, T. Tonuma, Y. Tendow, H. Kumagai,
T. Katou, K. Izumo, A. Hashizume, A. Hitachi,
M. Nishida, A. Yagishita, and T. Hamada

The spectra of Ta, Au, and Pb Ma and M~ X-rays induced by 84 MeV N ions were measured
by using a crystal spectrometer. I) ' 2 ) A flat crystal of EDDT(020) was used for measurement of
Ta M X-rays and that of Ge(lll) for Au and Pb . The detection of X-rays was made by usinga side window gas-flow type proportional counter with a 1 J.lm polypropylene window.

TheE (keV )
1.8

Ta

1. 7

1. 75

M X-rays

Q

v/:j

N /:j

z

z

z

2::

2::

2::

0!::,

z

2::

E (keV )l IIlIl I

2. 15

Au

M X-rays

4000

N - ions

(f)

c:

:::J
0

u

(f)

§0 2000

u

102

104

106

108

11 0

28 (deg.J

Fig. 1.
Ta M X-ray spectra obtained by
84 MeV N-ion and photon excitation.

28 (deg.l

Au M X-ray spectra obtained
Fig. 2.
by 84 MeV N-ion and photon excitation.

21

68

E (keV )
2. 5

2.45

Pb

M X- rays

b

.,.b

z

z

2

2

b

b

z2 z2

II! I IlI
3000

N - ions

2000

.8
c
::::J

0

u

Fig. 3.

Pb M X-ray spectra obtained by

84 MeV N-ion and photon excitation.
108

targets were self-supporting metallic foils with the thickness in the range of 2.2 to 2.8 mg/cm 2 .
They were placed at 60° with respect to the beams.

The estimated energy loss of the incident

ions in the target was less than 3.5 MeV. , The integrated beam current was kept constant at
each angle and the spectrometer was controlled automatically.
The spectra of N-ion-excited Ma and M{3 X-rays of Ta, Au, and Pb are shown in Figs. 1 to 3
in comparison with those of photon-excited ones.

The arrows in the figure denote the positionof MNn satellite lines, which correspond to the initial configuration of single M-shell and n
N-shell vacancies, estimated by the Hartree-Fock-Slater calculation by assuming the N-vacancies
being in N3 - ( 4d-) shell.
This may be the first case of the measurement of heavy-ion induced M X-ray spectrumby the crystal spectrometer. In contrast with previously reported KLn and LMn satellites, 3 )- 6 )the MNn satellite lines are not resolved in energy, except for the MN° line of each element and the
MN 1 line of Ta. The main reason may be that there are much more sub-shells in N orbit
than L or M orbits. In Fig. 2, the broken lines show the estimated positions of MNn satellites
by assuming the vacancies being in N2 - ( 4p-) shell in order to see the effect of different
configuration. In the actual case, vacancy-configuration will be more complex and multiplets
will be formed. Additional ionization of O-shell electrons would broaden each peak also.
The analysis of the data is in progress.

69

References
1)

Y. Awaya, Y. Tendow, H. Kumagai, M. Akiba, T. Katou, and T. Hamada: IPCR Cyclotron
Progr. Rep.,-.2_, 79 (1975).

2)

H. Kumagai, Y. Awaya, Y. Tendow, T. Katou, and M. Akiba: Reports I.P.C.R., (in Japanese),53, 153 (1977).
Y. Awaya, M. Akiba, T. Katou, H. Kumagai, Y. Tendow, K. Izumo, T. Takahashi,

3)
4)
5)
6)

A. Hashizume, M. Okano, and T. Hamada: Phys. Letters, 61 A, 111 (1977).
Y. Awaya, T. Katou, H. Kumagai, T. Tonuma, Y. Tendow, K. Izumo, A. Hashizume,
T. Takahashi, and T. Hamada: ibid., 75A, 478 (1980).
Y. Awaya: Electronic and Atomic Collisions, North-Holland, p. 325 (1980).
Y. Awaya, T. Katou, H. Kumagai, T. Tonuma, Y. Tendow, K. Izumo, T. Takahashi,
A. Hashizume, and T. Hamada: IPCR Cyclotron Progr. Rep., !l_, 73 (1979).

70

6-2.

A Target Chamber for X-Ray-Angular.. Distribution Measurement

Y. Awaya, I. Takeshita, Y. Tendow,
and T. Katou

A target chamber has been designed and constructed for the use in experiments mainly on
the angular distribution of X-rays. A sectional view of the chamber is shown in Fig. 1, where
the left and right parts with respect to the a-a' line show different sections. The chamber is 30 em
in inner diameter and 15 em in depth. The wall of the chamber is made of stainless steel and theupper and the lower lids and other parts that may be irradiated by stray beams are made ofaluminum.
aaSectional view of the chamber. A: target holder, B: target-haler support,
C: turn arm, D: target box, E: gate valve, F: port for beam transportation,
G: port for X-ray measurement, H: turn arm, 1: sliding saddle, J and J': stoppers,
K: flange with 0-ring, L: compact-type gate valve, M: bellow-duct.
Fig. 1.

The chamber contains a target holder A, a target holder support B, which defines the position
and the angle of the target with respect to the beam, and a turn arm C. The height and angleof B and the angle of C are adjustable without opening the vacuum system. The target is changed
without breaking the vacuum by lifting up the target holder by hands into the box D, which isconnected with the upper lid through a gate valve E. On the wall, there are two ports F forthe beam transportation, the one is connected to the beam duct from the cyclotron and the other71

to a Faraday cup. Besides, there are thirteen ports G for measurement of X-rays. These arepositioned at 25°,45°, 70°, 90°, 110°, 135°, 155°, - 30°, -60°, -90°, -120°, and -150° withrespect to the beam. The surface of the flange-joints of these ports is finished up accurately
so that the distance from the center of target to the center of every flange joint is made equal,
i.e. 185 ± 0.1 mm.
There is another tern arm H, which holds a Si(Li) X-ray detector and moves in air aroundthe target. The detector moves back-and-forth on the arm by sliding saddle I whose position isdefined by two stoppers J and J". We usually use the Si(Li) detector designed for a microanalyser.
The end-cap-pipe of the detector mounts a flange K which is connected to the port G through agate valve L and a bellow-duct M. The compact-type gate valve L is specially designed by one of
the authors (I. T.). The pipe slides in the flange K through greased 0-ring. Thus, the angle ofthe detector with respect to the beam is changed and the detector is set at a desired distancefrom the target without breaking the vacuum. When the energy of X-rays to be measured isso high that their attenuation is negligible, L and M are removed and the every port of G iscovered with a 50 J,Lm Be foil.
There are three apertures on the upper lid and four on the wall at level lower than G. They
are used for various purposes, e.g., for viewing the beam position by a television camera, as an
inlet for the electronic signals or providing bias voltages, an inlet of gases for the gas-target celland so forth. A photograph of the chamber is shown in Fig. 2.

Fig. 2.

Photograph of the chamber.

72

6-3.

Kr K{3/Ka X-Ray Intensity Ratio by 6 MeV/amu lon Bombardment

T. Tonuma, Y. Awaya, T. Kambara, H. Kumagai,
M. Kase, I. Kohno, A. Yagishita, and K. Izumo

Measurement of Kr Kt3/Ka intensity ratio was made by 6 MeV/amu ion bombardment as afunction of Kr gas pressure. We used ion beams of He, Li, B, C, N, 0, and Ne from the cyclotron.
K X-ray of Kr was detected with a Si(Li) detector.
The experimental apparatus, the condition of the measurement and a part of the experimental
data have been reported.!) ,l)Figure 1 shows Kr Kt3/Ka intensity ratios as a function of Kr gas pressure.

The value of Kr

Kt3/Ka ratio induced by He ion bombardment increases slightly with gas pressure.

The value for

Li ion bombardment seems almost independent of gas pressure. On the other hand, the values
for B, C, N, 0, and Ne ion bombardment decrease with increasing gas pressure and the values
decrease more rapidly for larger Z 1 of incident particles.
The values of K/3/Ka ratio without self-absorption, that are obtained by extraporation of thecurves to gas pressure of zero, 2 ) increase with Z 1 .
The gas pressure dependence of Kt3/Ka ratio gives information about the multiple inner shellionization. 2 ) On the assumptions that the value of fluorescence yield for each Kt3 satellite is thesame and that the ionization cross section of single K-shell and n L-shell electrons is given by thebinomial distribution formula, the average number of L-shell vacancies fiL can be derived from thedata. We estimated the effect of rearrangement on the K/3/Ka ratios in the simplest form. The
transition of M-shell electrons to L-shell vacancies give the largest contribution to the effect. We
took the rearrangement coefficient, f, as rL;r total and obtained the results of fiL values from the0.22~----~----~----~

·~X~

-•-He
------o-- Li·~--------b--8-•-C---o--N

0.14

-x-Q

0.1 2
0

-•-Ne

A~

L _ __ _ _ _....l..,___ _ _ _~_ _ ___;:.
..__,

100

200

300

P (Torr)
Kr Kt3/Ka intensity ratios induced by 6 MeV /amu ion bombardment
Fig. 1.
as a function of Kr gas pressure.

73

3

I

I

I

I

• f =0

2 -

.

0.22

0

...J

lC
0

i

g

-

ts

-

I

I

I

I

1 2

3 4

5 6

7 8

z,

I

I

I

I

~

1-

I

I

-

/

1-

9 10

I

~--

"0.18~-

~

I

I

,~

0.161-

Q

0I~ 0.201-

~

• •

I

0

•

0

1 -

I

1-

0

f = 0.4

0

I

I

I

l

-

-

I

I

I

I

I

I

2

3 4 5 6 7 8 9 10zl

Kr K,B/K~ intensity ratios without

The average number of L-shellvacancies fiL versus atomic number of theFig. 3.

incident particle zl .

circles show the experimental results andFig. 2.

self-absorption as a function of zl .

Solid

solid line shows the calculated ones.

gas pressure dependence assuming f equal to 0.4 as shown in Fig. 2, where rL and r total are thedecay rate of M-shell electrons to L-shell vacancies and the total decay rates, respectively. In the
figure the solid circles show the results without the rearrangement effect and the open circles show
the results with the effect. It is found that the effect is larger for larger Z 1 .
In Fig. 3 the full circles show the Kr K,B/Ka ratio without self-absorption as a function ofZ1 .

The Z 1 -dependence of the ratios was estimated by use of fiL values obtained from gas

pressure dependence.

We also assume that the ionization probability of an M-shell electron is

proportional to Z 12

and the ionization of 3d-electrons precedes that of 3p-electrons. The solidline in the figure shows the calculated results for f = 0.4 as a smooth curve for convenience.

References
1)

T . Tonuma, Y. Awaya, T. Kambara, H. Kumagai, and I. Kohno: IPCR Cyclotron Progr.

2)

Rep., 11_, 84 ( 1978).
T. Tonuma, Y. Awaya, T. Kambara, H. Kumagai, M. Kase, and I. Kohno: ibid., U_, 84 (1979).

74

6-4.

Chemical Effect1n

Cu L X-ray Satellite Spectra

M. Uda and K. Maeda

Chemical effect appeared in intensity distributions of Cu L X-ray satellite spectra has been
described in the last issue of IPCR Cyclotron Progr. Rep. I)

X-ray transition energies of thesatellites have also been calculated in the above mentioned report by use of the Hartree-FockSlater method whose computer program was written by Herman-Skillman. 2 )transition energies agreed with the observed ones.

The calculated

A quantitative explanation of the satellite

intensity distributions can not , however, be given by the above calculation.

In this report anindex to the solution of this problem will be given.
In the direct Coulomb ionization process , an initial electron vacancy distribution Yn of one
and n vacancies in the L and M shells, respectively can be expressed by a binomial one ,where PM is an ionization probability of the M shell at zero impact parameter.

y n is to be

independent of chemical environment, or an ionization cross section of the M shell should bedetermined only by the relation between the incident energy and species of the projectile, and thespecies of the target atom. 3 )Change in the intensity distributions of Cu L X-ray satellite spectra

can then be explained by electron transfer, via a valence band, from surrounding atoms to the atomof interest prior to L X-ray emission.
state to a L 1 Mn-l state as fn,n _1 .

Let us define a probability of the transfer from a L 1 Mn

Such a one electron transfer process occurs succesively.

Therefore, each of relative intensities of the L X-ray satellites y* is written as

x _ Cwn/ w~ )( l-fn n -1) ( Yn + fn+1 n Yn+1+ f

Yn--

'

n+ 2 , n +1 f n + 1 , n Yn+ z+ ········)'

where wn andware a fluorescence yield of the L Mn state and a mean fluorescence yield,

respectively.

For the diagram line we get

( 2)

1

yX = ( w0.

0I w)( y + f
0l' 0

y + f' f
Y. + ... .... .. )l2,1 1, 0 2(3)

If n is small, as in the case of Cu L X-ray spectra induced by 84 MeV N 4 +, we may write fn n ,

f.

' +l

Then Eqns. (2) and (3) are simplified asX

y n = (wn / w)(l - f)(yn + fyn+1 + f

2

Yn+ 2+ ········· ) .

(4)

and
( 5)

75

For the multiply ionized state L1Mn induced by 84 MeV N 4 +, we can estimate PM of Cu to
be 0.094 by the extrapolation of PM data 4 ) obtained from Y , Mo , Sn , and Ag.

From the PM

value thus determined we get the initial vacancy distribution in the Cu M shell, y n, which is
depicted in Fig. 1.
f is defined as( 6 )where r L and rv are widths of the L shell of Cu and the valence band for Cu bearing compounds.
As the widths of inner shells are less sensitive than the width of an outer shell to the change inchemical environment, we use the same theoretical value of rL (Ref. 5) for all the Cu bearing
compounds.

For the first transition elements , the width of the valence band can be represented
Then the valence band width of CuF 2 3 ) •6 ) may be replaced byby that of 3d 312 , 512 or M4 , 5 .

y~ changes with f.

the width of F 2p of this compound.

Such a feature can be seen in Fig. 2.

Using Eqn. (6) we get f for CuF 2 to be 45.4 X 10- /(256 + 45.4) X 10-4
4

= 0.15.

0.4

Fig. 1.

;;:,; 0. 2

An M shell vacancy distributionof Cu with PM = 0.094.
o ~~~--~~qL~¥L~?-~--

2

0

4

3

5

6

The distribution

is expressed by the binomial one.

A

vacancy configuration is given by L 1 Mn.

n

ID 1.0
I
(Y)

II

.:

~ 0.5

1. 0

n

Fig. 2.

An emitted Cu L X-ray

Fig. 3.

R versus f curves forintensity distribution as a functionn = 3 - 5.

of the number of vacancies in thethe meaning of R and f.

M shell, n.

See the text for

A parameter f isassumed to be from 0.15 to 0.8.
If we use CuF 2 as a reference compound, we can simplify the relative intensity relation asy* 1*cf ) y c f = o. 1s ) = R

y~(f )/y~(f=0 . 15) -

,

( 7)

76

which includes one parameter f alone.

The relation between R and f can now be drawn by

putting an appropriate f value into Eqn. (7), as shown in Fig. 3. Then from the observed valueof R we can determine the f value associated with the compound of interest. For more exact
evaluation of R the emitted X-ray intensity should be corrected by taking the self absorption
into account.

Such a correction is now in progress.

References
1)

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

2)

F. Herman and S. Skillman: "Atomic Structure Calculations", Prentice Hall Inc., Englewood
Cliffs, New Jersey (1963).

3)

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

4)

Y. Awaya, K. Izumo, T. Tonuma, T. Katou, Y. Tendow, H. Kumagai, T. Takahashi,

5)
6)

A. Hashizume, and T. Hamada: IPCR Cyclotron Progr. Rep., l_l, 76 (1979).
E. J. McGuire: Phys. Rev. A,l_, 587 (1971).
H. Endo, M. Uda, and K. Maeda: ibid., 22, 1436 (1980).

77

6-5.

Energy Straggling of C Ions in Metal Foils andFoil Non-Uniformity Effect

T. Takahashi, Y. Awaya, T. Tonuma, H. Kumagai,
K. Izumo, A. Hitachi, M. Nishida, and A. Hashizume

Recently, Sofield, Cowern , and Freemanl) pointed out that the departure of our experimental
energy straggling of C ions 2 ) •3 ) from the Bethe-Livingston theory may be ascribed to non-uniformity·o f the foil.

According to Sofield et al., square of the apparent energy straggling due to foil
non-uniformity is given by
2

2

2

2

( 1)

r; r = 2 ( 2£n2)(a f /~x) ( ~E ) ,where of is the thickness fluctuation (standard deviation), f::..x the mean thickness of the foil andf::..E the mean energy loss in the foil.
Using the experimentally observed straggling (fwhm) 7?exp and the theoretical value from theBethe-Livingston theory , 77BL' we calculated the ratio R c /R He in Ref. 2 , to evaluate the "true"
straggling for C ions in foils of unsatisfactory uniformity. Here, Rc is 77expf77BL for C ions and
RHe is the ratio for He ions (details are explained in Ref. 2). We admit that the ratio is inadequate
as a measure for deviation from the Bethe-Livingston theory , because Rc /RHe cannot cancel
the foil non-uniformity effect.
However, it should be noted that the value of (of/6x) 2 derived from the relation 1 )( 2)should be equal for both C ions and He ions, if Sofield's concept is valid. According to ourexperiment, (of/6x) 2 obtained from C ions is (6.7 ± 1.2) X 10-4 , whereas (of/6x) 2 obtained from
He ions is (- 4.8 ± 6.6) X 10-4 for Ag foils. For the other foils (of/6x) 2 is always larger for C
ions than for He ions as shown in Table 1. The difference is not within the limit of error except
Table 1.

Values of (of/6x) 2 derived from Eqns (1) and (2).

Foils(or/ 6x) 2 obtained fromthe experiment of ,...., 7(of/6x) 2 obtained fromthe experiment of ,. . , 7

MeV /nucleon He ions

MeV/nucleon C ionsAIAg

( 0 ± 5 .4) X 10 -4(-4.8 ± 6.6) X 10-4

( 3 .0 ± 0. 7) X 10 - 4 *Au(2.9 ± 0.4) X 10 - 3(4.0 ± 0.6) X 10- 3

Pb(8.5 ± 1.5) X 10-3

(12.9 ± 1.5) x 1o- 3(6 .7 ± 1.2) X 10 - 4*This value was obtained from the experiment using C ions of 5.31 MeV/nucleon.

78

for the Al foil. Therefore, it would be reasonable to consider that the difference between(af/f::.x) 2 for C ions and that for He ions is small but still exists.
The reason for the discrepancy shown in Table 1 might be explained by charge exchange
because of the small difference. Accordingly, it should be reserved to conclude that the carbon
ions of 5 - 7 MeV /nucleon are fully stripped, as has been claimed by So field et al.

References
1)
2)
3)

C.J. Sofield, N.E.B. Cowern, and J.M. Freeman: Nucl. Instr. and Meth., 174, 611 (1980).
T. Takahashi, Y. Awaya, T. Tonuma, H. Kumagai, K. Izumo, A. Hashizume, S. Uchiyama, and
A. Hitachi: ibid., 166, 587 (1979).
T. Takahashi, Y. Awaya, A. Hashizume, K. Izumo, H. Kumagai, T. Tonuma, and S. Uchiyama:
IPCR Cyclotron Progr. Rep., 12, 92 (1978).

79

6-6.

Helium Embrittlement 1n Prec ipitation-hardenable Alloys

H. Shiraishi , H. Shinno ,* N. Yamamoto ,* H. Yoshida* ,H. Kamitsubo, I. Kohno, and T. Shikata

It is well known that iron base austenitic alloys of high nickel (25 - 45 %) content have excellent low
swelling characteristic. However, several experimental data .suggest that these materials in a precipitation-hardened

state have higher sensitivity to neutron irradiation embrittlement than 316 or similar 300 series stainless steels.
From the standpoint of a reactor structural design, high strength and high ductility are desirable for reactor
operation at high temperature, but, in general , high strength reduces the ductility. This trend is substatiallystrengthened in the irradiated state. The neutron irradiation embrittlement at temperature higher than 0.5
Tm (Tm: melting point) is strongly correlated with the so-called helium embrittlement. In the present study, theembrittlement of helium injected materials was determined as a function of the tensile strength. The strength
was widely varied by various types of pre-injection and post-injection treatments. The present work aimed tofind out such a treatment which will give a good combination of strength and ductility.
Results of chemical analysis of the samples used are presented in Table 1. 7817 and 7818 are 1' Ni 3 (Ti , Al)
11and "( Ni Nb precipitation-hardenable alloys, respectively. Th~ specimens for tensile test were fabricated in
3

National Research Institute for Metals. The dimension of gauge section was 10 mm long , 4 mm wide, and 0.2 mm
thick. The conditions of solution treatments and helium preinjection treatments are given in Table 2.
Table 1. Chemical composition of used samples. (wt.%)

c

Ni

Cr

Mo

Ti

Al

7817

0.021

40.2

14.6

3.19

2.01

0.87

7818

0.024

39.9

14.7

3.03

0.31

Nb

2.96

Si

Mn

B

0.47

0.19

0.00490.48

0.19

0.0048The specimens were deformed by the tensile test machine before the helium injection. Helium was injected
at constant high temperature (650°C), using the cyclotron. Conditions of helium injection and post-injection
treatment are also given in Table 2. The helium concentration amounted to 5 to 10 atomic ppm. The tensile
4
test was conducted at 650°C in vacuum of 3 X 10- 4 Pa with a strain rate of 5 X 10- /s. Conditions for
six kinds of treatments done before helium injection are presented in Table 2. Solution treatment and 10 %pre-strain treatment followed by two kinds of aging treatments resulted in the highest precipitation strengthening
and the state of slightly averaged condition, respectively . These conditions were decided from the result of
preceding experiment on the aging response of 7817 alloy. 7818 alloy was not precipitation-hardened so muchas 7817 alloy by these pre-injection treatments.
1
The result of the tensile test is ,shown in Table 2. 7817 alloy hardened by "( -precipitation has a higher
11
sensitivity to the helium embrittlement than 7818 alloy hardened by "( -precipitation. In 7817 alloy,
averaging improved the ductility and the combination of 10 % pre-strain and averaging gave the best combinationof strength and ductility. In 7818 alloy, the decrease of total elongation in the solution treated and aged
condition was very small. The 10 % pre-strain seemed to have deleterious effect on ductility in this case.
The post-injection anneal recovered the ductility in 7817 alloy , but the reversed effect was observed in 7818
alloy. These complex behaviours of the helium embrittlement of alloys precipitation-hardened by intermetallic
compound are seen to be dependent on the aging process and their inherent tensile strength, as illustrated inFig. 1.

The tensile strength was varied in a wide range by various pre- and post-injection treatments.

Figure 1

shows that the degree of helium embrittlement is mainly determined by the alloy strength , regardless of the alloy* National Research Institute for Metals.

80

Table 2.

Mechanical properties of helium injected 7817 and 7818 alloys (Fe-40Ni-15Cr).
Test temp.: 650°C, Strain rate: 5 X 10- 4 /sec

Pre-injection
treatment

7817

{ 5
ST
1000°C, 30min 0{~ST+
700°C,300h

10%PS

Tensilestrength(Mpa)

Uniform
elonga.

(%)

(%)

650

410
281

701
624

3.3
35.2

3.3
43.7

650

770
709

870
865

1.8

1.8

5.2

26.6

650

625
624

732
775

5.7
7.5

5.7
35.3

650

449

632

650

574
455

776
686

22.0

2.2
33.2

841
818

907
928

1.2
4 .5

24.4

650

545

698

650

825
759

910
825

650

522

686

650

194
174
470

475
482
602

Post-injection
treatment

650
10% PS +700°C,30h

10% PS +{{~700'C, 300h { 1~7818
ST
1100°C,
30min

Total
elonga.

0.2% proof
stress(Mpa)

He cone. Injec.
(at. ppm) t(~j"Sample
No.

650

12.3
no experiment

1.9

8.0
no experiment
5.6
7.3
8.2
no experiment
27.4
31.5
7.3
no experiment

15.3

1.2
8.2
7.0
24.4
9.6
31.4
39.2
14.5

{~
ST+
750°C, 300h { ~10%PS{~
10% PS +700°C,30h { ~10% PS +700°C,300h { ~

650

243
223

531
479

19.3
23.7

32.5
33.0

650

224
234

528
488

18.3
17.7

38.3
43.1

650

342
347

518
514

17.1
19.2

17.9
28.1

650

287
498

497
648

21.0
12.6

23.2
29.3

650

312
473

499
615

12.5
11.5

15.2
23.9

ST+
750°C, 300h
650°C,300h
ST +700°C, 300h
650°C,300h+{ 100

650

234
250

516
521

22.0
22.3

39.8
43.3

10

650

287
329

570
577

22.6
29.3

34.9
37.3

ST+
700°C,300h+{ 0

ST: Solution treatment ; PS : Pre-strained

81

c
0

-+-'

cu
c

DO

0

QJ

0
0

78 17
7818

Solid : Helium injected
Hollow: No heli um

Ten sil e strength (Mpa)

Fig. 1. Relationship between total elongation and tensile strengthof helium injected Fe-Ni-Cr austenitic alloys. He cone.: 5 - 10
atomic ppm; Test temp.: 650°C; Strain rate: 5 X 1o- 4 /s

type , except for one example of 7818 alloy which was 10 % pre-strained and aged at 700°C for 300 h.
At the stress level of 500 Mpa, the helium embrittlement was suppressed almost perfectly. The total elongationof 5 % can be ensured at the tensile strength of 650 Mpa. The result of the pre-injection treatment (10 %pre-strain + 700°C, 300 h) in 7817 alloy is unusual and the reason or the mechanism for the improvement should
be investigated more carefully before arriving at any conclusion, but makes one to expect further improvementin the total elongation at such a high strength level.

82

6-7.

Backward Secondary Electron Emission from

AI, Cu, Ag, and Au Targets under High Energy
7N +and N 4 +lon Bombardments

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

In the last volume we reported on total backward secondary electron emission (BSEE) yields
under proton bombardments, ')'(p), for AI, Cu, Ag, and Au targets in the incident energy range from
5 to 12 MeV .1)
In that report it was shown that "Y(P) is in proportion to the specific electronic energy loss
(SEEL) of protons, SP, in target materials, and that the ratio "Y(P )/Sp is independent of proton
incident energy.
In the present report we study BSEE yields for N7+ and N4+ ion bombardments. The
apparatus and experimental procedures are the same as those in the previous report.
Ions N4+ are directly accelerated by the cyclotron. On the other hand, ions N7+ are producedby passing N4+ ions through a 6 Jlm aluminum foil. Ions N 7+ are separated and guided to thetarget by a magnetic analyser. The distance between the aluminum foil and the target is about
8 m.

Figure 1 shows the total BSEE yields from Al, Cu, Ag, and Au targets for N7+ and N4+ ion
bombardments, ')'(N 7+) and ')'(N4+), at an incident energy of 6.8 MeV/amu. Values of 49')'(p)and 16')'(p) for this incident energy are also shown for reference.
According to Oda and Lyman, forward SEE yields for various projectiles with the same
velocity are proportional to the square of the effective charge numbers Zeff of the projectiles. 2 )The effective charge number of a N 7+ ion is nearly equal to 7 at this incident energy. 3) The
charge number of N7+ within the secondary electron escape depth will therefore be 7 at this energy.
However, values of ')'(N 7+) are smaller than those of 49-y(p) for all these target materials. Further

c
0

~
18.0
c
2

u

Q)

w

f'z
16 y ( p ) - - 6 .
p----///!Y .....

.....

,.,...li'

Z2 Target atomic number

Fig. 1.
Total backward secondary
electron emission ratios under N 7 + andN4 + ion bombardments for Al, Cu,
Ag, and Au target materials. Incident
energy is 6.8 MeV /amu. Squares andtriangles show values of 49 and 16
times those of "Y(P ), respectively. The
values of "Y(P) were taken from Ref. 1.

83

experiments are necessary to elucidate the departure of the BSEE yield from the proportionality
to zeff 2.
According to electron loss cross sections of N4+ ions in the energy region concerned here, thecharge number of N4+ ions is not increased so much and nearly equal to 4 within the secondary
electron escape depth. 4l However -y(N4 +) is about twice as large as 16-y(p ), though it is of course
smaller than -y(N 7+ ).
This will be explained as follows: the charge number of a N4 + ion will appear to be 4 for atarget electron when it is far from the N4 + ion, where the charge of the nitrogen nucleus isscreened by the remained three electrons of the N4 + ion. But the charge number of the N4 +ion will appear to be 7 for a target electron which is nearer to the nitrogen nucleus than all thethree electrons. Therefore -y(N 4 +) will have a value between those of -y(N 7 +) and 16-y(p ).

References
1)

A. Koyama, T. Shikata, and H. Sakairi: IPCR Cyclotron Progr. Rep., 13, 94 (1979);
A. Koyama, T. Shikata, and H. Sakairi: Japan. J. Appl. Phys., 20, 65 (1981).

2)

N. Oda and J.T. Lyman: Radiat. Res., Suppl., ], 20 (1967).

3)
4)

P.G. Roll and F.E. Steigert: Nucl. Phys., .!2, 54 (1960).
T. Tonuma, Y. Miyazawa, F. Yoshida, T. Karasawa, T. Takahashi, and S. Konno: J. Phys.
Soc. Japan, 34, 148 (1973).

84

6-8.

Measureme nts of the Compton Profile and Angular Correlationof Positron Annihilation Radiationsin Amorphous Mg 70 Zn 30

N. Shiotani, N. Sakai, T. Okada,
H. Sekizawa, and T. Mizoguchi

A study was made on the electron momentum distribution in amorphous Mg 70 Zn 30 alloy by measurementsof the Compton profile and angular correlation of positron annihilation radiations.
Amorphous Mg 70 Zn 30 ribbons were prepared by melt spinning method. The thickness and the width of
the ribbon were about 50 pm and 2 mm, respectively. The ribbons of 20 mm in length were put side by sideand stacked one over another to form a specimen of 20 mm in length, by 20 mm in width, and 0.6 mm inthickness for the positron annihilation experiment and that of 20 mm in length, by 20 mm in width, and by
1.0 mm in thickness in an envelope of Mylar sheet of 0.01 mm in thickness for the Compton profile measurement.
241
Am source of 300 mCi and a pure Ge
The Compton profile was measured using 59.54 keV 'Y rays fromdetector. The specimen was kept at room temperature in vacuum. The scattering angle was chosen to be 150
degrees. The overall momentum resolution was 0.66 atomic units (a.u.) in full width at half maximum. The
multichannel pulse height analyzer with a built-in digital stabilizer was used. Two 'Y rays of 59.4 ke V from119
mSn were used as the standard peaks.
Am and 23.8 keV fromX 10 4 .
1
about
were
Compton proflle
241·-......

Amorphous Mg 10 Zn 3o········...

c·······......
······························ ................

0

The accumulated counts at the peak of the2
Pz 1n a.u.

3

4

Fig. 1. The Compton profile C(pz) of theamorphous Mg 70 Zn 30 alloy measured at 300 K.
The corrections were made of the back ground ,the detector efficiency , the self-absorption andthe long tail effect.

The measured Compton proflle C(P z) of the amorphous Mg 70 Zn 30 is shown in Fig. 1. Corrections weremade of the backgrounds, the effect of the energy-dependent efficiency of the detector, the self-absorption in thespecimen and so-called "long tail" effect. The effect of multiple scattering is not corrected. The observed
proflle consists of a parabolic valence electron part and a broad core electron part. Due to the low momentum
resolution , a break at the Fermi momentum is smeared and hard to be seen. However, the parabolic part of theobserved proflle of the amorphous Mg 70 Zn 30 alloy is very much similar in shape to that of a pure magnesium
1
single crystal measured with the same experimental conditions. ) This fact strongly indicates that the bulk of
the valence electrons in amorphous Mg 70 Zn 30 alloy behaves like free-electrons.
The angular correlations of positron annihilation radiations were measured using a parallel slit system. The
geometrical angular resolution was measured to be 0.61 milliradians or 0.084 a.u. in the momentum resolution.
The angular correlation curves were measured at 80 K and 300 K. The specimen was kept in vaccum at both4
temperatures. The accumulated coincident counts were over 5 X 10 at the central portion of the angularcorrelation curves. The observed angular correlation curves N(pz) and their slope illN(pz)/~Pz I are shown in
Figs. 2 and 3. Owing to much better momentum resolution in the angular correlation measurement than in theCompton proflle measurement , it is clearly seen that the angular correlation curves consist of the parabolic mainpart and the broad tail with much smaller intensity. There is a definite break at the Fermi momentum on eachcurve. Comparing the observed angular correlation curves of the amorphous Mg 70 Zn 30 alloy with that of a pure

85

3

Amorphous Mg 70 Zn 30

80 K

(j)

300K

(j)

c

::::J

c

~ 2

-e

[1J

c

c

ri:

::J..."'

<: 1

<

2

2

0

Pz in a.u,

Pz in a.u.

. ... ._......
0...L ..............

0Pz 1n a.u.

Fig. 2. The angular correlation curveN(p z ) of the amorphous Mg 70 Zn 30 alloy
measured at 80 K and its slopes.

Pz

Fig. 3.

1na.u.

The angular correlation curveN(pz) of the amorphous Mg 70 Zn 30 alloy
measured at 300 K and its slopes.

Mg single crystal measured with the same experimental conditions, 2 ) we find the following facts : 1) the breakat the Fermi momentum is very much smeared in the amorphous alloys, and 2) the momentum-dependentenhancement effect which appears in the case of simple metals as characteristic bulge of the main parabolic part
is not seen in the amorphous alloys. Short mean free path of the electrons and the positrons due to therandomness of the lattice potentials would cause in general smearing of the break, but little is known
quantitatively. On the other hand it has been known from studies of crystalline simple metals and alloys that aheavy smearing of the break occurs when a positron is trapped by vacancy type defects 3) or localized in a region
where an attractive potential for the positron is formed by inhomogeneity of constituents~)
The momentumdependent enhancement effect which appeared as the bulge of the parabolic part is characteristic for the special
case of a positron freely moving in an electron gas. If the positron is not free to move, the enhancement
effect may appear in a different way. Thus the two experimental findings mentioned above strongly imply
that the positron is not free to move in the amorphous Mg 70 Zn 30 alloy. The positrons are localized mostprobably in low density dilated regions inherently contained in amorphous structures.

References
1)
2)
3)
4)

N. Sakai and H. Sekizawa: to be published.
N. Shiotani, T. Okada, H. Sekizawa, and S. Wakoh: J. Phys. Soc. Japan, 50, (1981) in press.
J. H. Kusmiss and J. W. Swanson: Phys. Lett., 27A, 517 (1968).
P. Kubica, B. T. A. McKee, A. T. Stewart, and M. J. Stott: Phys. Rev. B, U , 11 (1975).

86

6-9.

119

Sn Emission Mossbauer Study of

119

Sb Adsorbed on a-Fe 2 03

T. Okada, H. Sekizawa, F. Ambe, and S. Ambe

A study was made on the electronic states of dilute tin ions on the surface of hematite(a-Fe 2 0 3 ) by means of 119 Sn Mossbauer emission spectroscopy. The 119 Sn source is realized
by utilizing the EC decay of 119 Sb (Fig. 1) adsorbed on the surface. Hematite is a corrumdum
type iron oxide with a rhombohedral symmetry R3C. Below 260K, which is called Morintransition temperature, hematite is antiferromagnetic, while it becomes weakly ferromagnetic above
260K by slight canting of the antiferromagnetic sublattices. The Neel temperature TN ofhematite is 950K.
Radioactive 119 mTe was produced by bombarding a tin plate with 40 MeV a-particles fromthe cyclotron. The nuclide was chemically separated from the solution containing the dissolved
target. 119 Sb arising from the 119 mTe was repeatedly separated in a carrier-free state. Then,
hematite powder was dispersed in a slightly acidic aqueous solution containing the 119 Sb 5 + ions.
The resultant suspension was stirred in order to let the hematite adsorb the 119 Sb ions on thesurface. The hematite powder was filtered and dried in vacuum at room temperature and thisis called specimen (A). Then, a number of powder specimens were subjected to two hour heattreatments in air at various temperatures so as to diffuse 119 Sb ions into the specimens; the heat
treatments were done at 200°C (B), 420°C (C), 500°C (D), and 700°C (E). Another specimen(F) was obtained by coprecipitating 119 Sb(V) and Fe 3 + from an aqueous solution with subsequentcalcination in air at 700°C for two hours.
Mossbauer emission spectra of 119 Sn (resulting from the EC decay of 119 Sb) were taken against
a BaSn0 3 absorber at room and liquid nitrogen temperatures.
The spectra for the specimens (A) to (F) are shown in Fig. 2. From the values of isomer
shifts, it is certain that the valence states of tin ions resulting from 119 Sb 5 + are Sn 4 + in all the
specimens. Even in the "as adsorbed" specimen (A), there can be seen a remarkable broadeningof the emission line. We attribute it to magnetic interaction on the tin ions from the magneticallyordered hematite matrix through the supertransferred hyperfine interaction mechanism. The
average hyperfine magnetic field increases by heat-treatment as can be seen for (B)-(E). The
11 9mTe

4.7dcomplex23.9 keV

0

Fig. 1.
Decay scheme of
Te and 119 Sb.

11901

87

- 14

0

+14

Velocity (mm; s)

- 14

0

+14

Velocity (mm ; s)

Mossbauer emission spectra of 119 Sb adsorbed on hematite. (A):Fig. 2.
"as adsorbed". (B) - (E): after two hour heat-treatment at 200°C (B),420°C (C), 500°C (D), and 700°C (E). (F): coprecipitated and calcinedfor two hours at 700°C.

spectrum of (E) is almost equal to that of (F), which means that after two hour heat-treatment
at 700°C the adsorbed 119 Sb 5 + ions diffuse into the matrix deep enough to feel the same
supertransferred hyperfine magnetic field as the coprecipitated ions. The fact that no diamagnetic
119
Sb 5 +
component exists in spectrum (A) is especially interesting. It means that all the adsorbed
ions are bound to Fe 3 + ions of the matrix through 0 2 -without forming three-dimensional clusters.
The detailed report of the investigation in progress will be published elsewhere.

88

X-Rays Induced by Collisions between 110 MeV

6-10.

Ne Ions and Gases
T. Kambara, Y. Awaya, A. Hitachi,
M. Kase, I. Kohno, and T. Tonuma

X-rays from 5.5 MeV/amu highly ionized Ne-ion bombardment on gases of atomic number ZT ._: :;: 10 werestudied. Most of the observed X-rays are from the radiative electron capture (REC) and the electronic transitionsin the projectile ions. A Si(Li) detector was used in most of the measurements, and a crystal spectrometer wasused only in high resolution measurements of X-rays emitted from the projectile ions. The target gases were
H2 , He, CH 4 , N2 , 0 2 and Ne whose pressure ranged from 0.5 to 300 Torr.
Ne-ions of 120 MeV from the cyclotron were led to the gas target cell. The gas pressure was monitoredby an a-tron gauge. The beam energy at the center of the cell was reduced by about 10 MeV. Such reduction
is caused by the energy loss in the beam entrance window (7 Mm thick A1 foil) and the target gas. The charge
state of the ions in the cell is considered to be in equilibrium: about 80% of the ions are 10+ (bare), about
20% are 9+ (H-like) and a few percents are 8+ (He-like).!) Emitted X-rays passed through a 4 Jlm thick Mylar
foil window and were detected by either the Si(Li) detector or the crystal spectrometer. The Si(Li) detector
was placed at 90° to the incident beam direction and the crystal spectrometer at about 116°. The resolutionof the Si(Li) detector was about 270 eV (FWHM) at 6.4 keY. A TAP crystal (2d = 25.69A) and a gas flow
proportional counter were used in the spectrometer, the resolution of which was about 7 eV (FWHM) at 1.25 ke V
(Mg K X-ray).
Figure 1 shows an X-ray spectrum measured by the Si(Li) detector when the target was N 2 gas at about 20
Torr. Two peaks appearing close together at about 1.0 and 1.2 keY correspond to the K X-rays from the
projectile ions. The broad peak near 4 keY corresponds to the REC X-rays. Figure 2 shows high resolution
spectra of K X-rays from the projectile measured by the crystal spectrometer when the target was N gas at about2
50 Torr. It was found that the peaks at 1.0 and 1.2 keY observed by the Si(Li) detector originated in the one
electron transitions in the hidrogen-like Ne 9 + ions: the 1.0 keY peak was from the 2p-1s transition and the 1.2 keY
peak is a superposition of the lines from the np-ls (n=3, 4, 5, 6) transitions. The measured X-ray energy values,
after the correction for the Lorentz transformation, agree with the calculated ones from the Dirac equation within
0.5%.
K- Xray from
Projectile ions

2

c

::J

0

u

Fig. I.

Spectrum of X-rays

from Ne-ion bombardment on

2

3

4

Energy ( keV )6

7

20 Torr N 2 gas, measured by theSi( Li) d et ec tor.

89

2p- ls( a)

3p- ls
2 000

( b)

2c

:::J

0

u

4p - lsI

1 000

5p- lsI 6p- l sIo ~----------~------------~------

1.03

1.02

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

1.20

Fig. 2.

1.35

1.30

1.25

En ergy (keV )Energy (ke V)

High resolution K X-ray spectrum from Ne-ion s incid ent on 50 Torr N 2

gas, measured by the crystal spectromet er.

The profile of the REC spectra reflects the electron momentum distribution in the target. We have calculated
the peak positions and widths by the impulse approximation 2) with the approximate wave function given by
Slater 3 ) for the target electrons. In the calculation, we assumed that 1) incident ions are 10+, 2) target gas is of
atomic particles and 3) only the outermost shell electrons of the target are captured. The REC cross section is
given by the impulse approximation as follows:dEx d!1x
where dQx is the solid angle , Ex is the energy of the REC X-ray quanta, p 0 =mv0 with ion velocity v0 and electronmass m, pt is the mom en tum of the target electron to be captured and ~n f is the capture cross section of free2electrons by the incident ions. The 8 -function guarantees energy conservation and j ct>(p) is the momentum
distribution of the target electrons. The approximate wave function of Slater gives the momentum distributionJ

as follows:s/

2 ( p.2+ p 2 ) 4. . . 12'SI
I cD ( pl. ) = 8 p S 7rofwhere p =Z me 2/hn* with screened nuclear charge Z and effective principal quantum number n*. Values
2
sc
s sc
Table 1 lists also T s, the average kinetic energy which is equal to Ps /2m.
n* and Zsc are listed in Table 1.

Table 1.

The values of the effective principal quantum number (n*),
screened nuclear charge (zsc), and average kinetic energyof the target electrons (Ts = p~ I 2m).

H2

CH 4

N2

02

Ne

2

2

2

2

1.7

3.25

3.9

4.55

5.85

39.3

35.9

51.9

70.4

117

He

n*
zsc
T s (eV)

13.6

90

•
•

1.2

.I

( a)

1.0

~ 0.8

/.

_y

•

~ 0.6

s

LL

04

4.35
>Q.)
_y

2c

( b)

4.15

\

>Q.)
_y

c
0

4.1 0 ~

•

Q)

E

:::l

· ~ 4.30

~
m

0.

><

u

>~
Q)
cQ)

~
Q)

w

~

>-

••

4.25

cQ)

4.05 _y

m
Q)

Q_

Q)

Q_

0.2

0 1 2

6 7 8
CH4 N2 0 2

H2 He
Fig. 3.

Dependence of REC peak on the target.

10 Z rNe Target(a) width , (b) position.

The solid lines show the calculated values and the dots are from the leastsquares fitting of the experimental d ata.

The results of the calculation is shown in Fig. 3 with the experimental data. The experimental values of thepeak widths and positions were derived from the observed spectra by the least squares fitting. Values of peakwidth lie on two lines in the figure, which correspond to n=1 shell for H 2 and He, and n=2 shell for CH 4 , N2 , 0 2
and Ne. The agreement between the experimental data and the result of the calculation is good. On the other
hand, the experimental peak positions were reproduced by the calculation as far as their relative values areconcerned. The reasons for it may be considered as follows: 1) we neglected the contribution from Ne 9 + which
may shift the peak to lower energy; 2) the REC peaks are broad and there is some uncertainty in defmin~ the peak
position by the least squares fitting; 3) the beam energy at the center of the cell may be lower than that
estimated.
Further experiments and analyses, such as the measurement of the angular distribution of REC X-rays, are
now in progress.

References
1)
2)
3)

J. B. Marion and F. C. Young: "Nuclear Reaction Analysis Graphs and Tables", North Holland, p.45 (1968).
M. Kleber and D. H. Jakubassa: Nucl. Phys., A252, 152 (1975).
J. C. Slater: "Quantum Theory of Atomic Structure", McGraw-Hill, New York,!, 369 (1960).

91

7. RADIOCHEMISTRY AND NUCLEAR CHEMISTRY

7-1.

Chemical Separation of

18

F 1n

the

3

He Activation

Analysis of Oxygen

T. Nozaki and Y. Terai

We have found an excellent method of separating 18 F in the charged particle activationoeanalysis of oxygen by the 16
He, p ) 18 F reaction. This oxygen analysis has been regarded as
useful for many years in the science and industry related to high-purity substances. Relatively
small number of matrices, however, have been analysed by this method, principally because of thefollowing reasons: I) the accessibility of 3 He bombardment has been rather limited, and 2) 18 F
in the bombarded sample should usually be separated from various positron emitters formed

simultaneously by difficult and tedious procedures.

We made considerable efforts to set up

a manual for the chemical separation of fluorine from each matrix using the distillation offluorine as the principal step. Although this distillation is often used in quantitative analysis,
it cannot be regarded as the best method when used in activation analysis. A notable time ofcareful operation is needed for it, and the 18 F in the distillate should be converted into achemical form suitable for counting and carrier-recovery measurement.
Our present method makes use of the following properties of KBF4 : 1) it can be precipitatedand recrystallized from strong acid solution, because its solubility is 2.6 gjf at 20°C and 38 g/f at
100°C in water and is nearly the same in 1 : 3 HCl and 1 : 3 HN0 3 , 2) scavenging with Zn(OH) 2
is possible in its recrystallization from water; it is completely inert to both oxidation and reduction,and thus the oxidation states of impurities can be changed in its recrystallization.
The 18 F separation in the KBF 4 method consists of the following four steps.
1) Dissolution of the sample after the surface-contamination removal in an acid mixture
containing I 00 - 150 mmol of HF carrier in a closed polyethylene bottle.
2) Addition of H 3 B0 3 (2 - 3g) and 3 M KCl (20 mf) to the solution; its heating andcooling; filtration of the resultant KBF 4 precipitate; and washing with a KCl solution.
3) Dissolution of the KBF 4 in hot water (50 - 70 mf) containing ZnC1 2 (I mmol) or
another reagent for the scavenging; precipitation of the scavengers and its removal by filtration;
acidification of the filtrate and its cooling to precipitate KBF 4 , and filtration of the precipitate
and its washing with CH 3 COOK solution and ethanol.
4) Radioactivity measurement and carrier recovery measurement by weighing after drying.
The scavenging can often be omitted for a matrix containing over 1 ppm oxygen or giving nomarkedly high positron activity from itself.
This method can be applied to almost all matrices. The time required for the process is
usually less than one hour and sometimes under 30 min. The carrier recovery is 40 - 80 %.
This KBF 4 process demonstrates its superiority to the distillation-involving process especially inthe analysis of Ge, GaAs, and Zn, from which volatile radioactivity of 73 Se, 76 • 77 Br andradio-germanium, respectively, are formed.

Since, KBF 4 contains as much as 60.4 % of fluorineand since it is of rather low density, the self-absorption of positron annihilation radiation is very

92

''

0

'

200

400

600

1000

Time / min.

Fig. 1.
Decay curves of 18 F for various metal
matrices (Ge, GaAs, and Zn).

small even when a large amount of fluorine is added as carrier.
are shown in Fig. 1.

Decay curves actually observed

Down to 1 ppb of oxygen can be shown to be thus determined, when

an improved coincidence counting apparatus with a much lower background than our present
counter is used.
An ultra-compact cyclotron has recently been developed for the production of radioisotopesof low atomic numbers for medical use.

A similar machine is going to be used for activation

analysis, giving much more chance of 3 He bombardment that at present.

93

7-2.

18

Recoil Range of

F Formedby Various Reactions

T. Nozaki, M. Iwamoto, and K. Usami

Measurement of the distribution of forward recoil range of 18 F formed by various reactions
was continued by the same technique as described previously. I) The distribution curves for the
18 O(p, n) 18 F and 20 Ne(d, ~) 18 F were newly obtained, and a slight correction was found to benecessary in the curve for the 20 NeCHe, ~p) 18 F reaction.

The result is shown in Fig. 1.

- : 8 MeV)
( ····-- : 14MeV

/-,
\

\

I~

\ '\Ne + d (6MeV )
I

--~

\

\

\

/
/

1. 0
Catcher thickness ( mg/ cm 2 )', O+a (35MeV)

~'

'~

1.5

Distribution of forward recoil range of 18 F in Si formed byvarious reactions.
( ) : incident energy
Fig. 1.

Reference
1)

T. Nozaki, M. Iwamoto, K. Usami, K. Mukai, and A. Hiraiwa: IPCR Cyclotron Progr. Rep.,u_, 106 (1979).

94

7-3.

Heat Treatment Behavior of Oxygen in Silicon
as Measured by Charged Partie le Activation

T. Nozaki andY. ItohBy the use of activation analysis with the 16 0eHe, p) 18 F reaction, a method has beendeveloped for the measurement of oxygen depth profile in silicon up to a few hundred micrometersfrom the surface. This measurement now attracts great interest in the research and industry
relating to semiconductor silicon. A device was set up for the activation of oxygen with an equal
probability along the depth in the measurement portion of the sample. Then, silicon wafers ofknown oxygen concentrations were heat-treated under various conditions and the resultant oxygen
profiles were measured. Infrared spectrophotometry was also used to know the change of thephysical state of oxygen.
The device is shown in Fig. 1. The activation of oxygen with an equal probability iseffected by an absorber assembly rotating in the 3 He beam path. The absorber assembly consistsof several aluminum foils set in a frame, with their thicknesses and widths being suitably selectedfrom the excitation functions for the activation reaction and the energy loss curve for 3 He particle
in aluminum. Some fluctuation, however, is inevitable in the oxygen activation along the depth,
as is illustrated in Fig. 2. This curve was obtained by the bombardment of stacked Mylar foils
and used as a standard in the oxygen profiling. Silicon sample after heat treatment andbombardment was etched stepwise with HF-HN0 3 , and 18 F activities in the resultant etchingsolutions were measured by Ge(Li) detecter together with the decay curves. The thickness
2.0. - - - - - - - - - - - - - - - - - ,

1.5
Q)

>

LL

"'

0.5

oL---~1~07
0--~~--~300

Depth for Si

Fig. 1.
Device for the activation ofoxygen in an equal probability along
the depth.

Fig. 2.

(fJ. m)Calibration curve.

95

removed in each etching was known from the decrease of the wafer thickness measured by a dialgauge.

The oxygen distribution along the depth was thus obtained as a histogram.

Oxygen distribution s in silicon wafers before and after heat treatment in argon are shown in
Fig. 3. Initial oxygen concentrati ons of the samples were 11 wt. ppm and 9 wt. ppm for sample A
and H, respectively. The temperatur e and duration of heat treatment were 1250°C and 100 h.
With heat treatment in nitrogen, no remarkable change was observed in oxygen distribution . With
heat treatment in oxygen, the resultant distribution curve was found to vary according to theinitial oxygen concentrati on in the sample.

1.0

More detailed study is now in progress.

..--·----·

A(As grown )·~~·------.---

c

•

~

2:'

~

j5

~

0.5

-l

~

0

I-

0
L-1

0

100

200
Depth (,u m )300

Fig. 3.
Oxygen distribution after heat
treatment in argon (1250°C, I OOh).

96

7-4.

119

Isomer Shift of

Sn 1n Binary Compounds of the ElementsfromIndium to Iodine

F. Am be and S. Am be

We reported Mossbauer emission spectra of defect 119 Sn atoms in binary compounds of typicalelements in the 5th period of the periodic table.0 - 4 ) The spectra were obtained on 119 Sb- and119
mTe-labeled sources prepared by radiochemical procedures. The method has a great advantage
over the ion-implantation 5 ) in that the sources obtained are free from local damage of the matrix
induced by the energetic incident ion and are also free from local disturbance of the lattice due toHbringing-in" of an extra atom.
The results accumulated so far in our laboratory have led to a systematics of isomer shift forthe defect and normal 119Sn in the binary compounds, combined with the data of absorption
measurements. 3 ) , 6 ) As seen in Fig. 1, the isomer shift of 119 Sn shows a clear tendency to increase
with increase of the atomic number of the nearest neighbor atoms. The observed correlation
indicates that more electronegative neighbor atoms increase s-electron density at the 119Sn nucleus,
9

4-

~10

o ll

. 7

-

08

I

(f)

E
E

3r-

0

. 5

c:

(/)
<U

OJ
(f)

>
+-'

-

03

£

(f)

04

Cu
E

06

0

~

2r-

ol

02
rI

I

I

I

I

49

50

51

52

53

Atomic number of the nearest neighbor atoms

Isomer shift of defect and normal 119 Sn in binary
Fig. 1.
compounds of the elements from indium to iodine. Opencircles refer to defect 119 Sn in emission measurements andclosed ones to normal 119 Sn in absorption measurements.
1. In 119 Sb, 2. In 2 119 mTe 3 , 3. Sn 119 Sb , 4. Sn 119 mTe,
5. SnSb , 6. Sb 2 119 mTe 3 , 7. SnTe, 8. 119 Sb 2 Te 3 ,9. 119 Sbl 3 , 10. Snl 2 , 11. 119 mTel 4 .

97suggesting domination of p-character in the tin-ligand bonds. The systematics can be said to berather remarkable in view of the variety of structures and types of bonding involved in the binary
compounds.
The investigation is now being extended to compounds of cadmium and silver.

References
1)
2)
3)
4)
5)
6)

F. Ambe, S. Ambe, H. Shoji, and N. Saito: J. Chern. Phys., 60, 3773 (1974).
F. Ambe and S. Ambe: Bull. Chern . Soc. Japan, 47,2875 (1974).
F. Ambe and S. Ambe: J. Chern. Phys., 73 , 2029 (1980).
F. Ambe and S. Ambe: IPCR Cyclotron Progr. Rep., U_, 112 (1979) .
G. Weyer, J. W. Petersen, S. Damgaard, and H. L. Nielsen: Phys. Rev. Lett., 44, 155 (1980).
N. N. Greenwood and A. Timnick: J. Chern. Soc. A, 1971, 676.

98

7-5.

A Mossbauer Emission Study of Defect

11 9SnAtoms

in Proton- and a-Irradiated SnSe

S. Am be and F. Am be

We are studying the chemical states of dilute impurity 119 Sn atoms in metals andsemiconductors by Mossbauer emission spectroscopy using cyclotron-produced 119 Sb and 119 mTeas the source nuclides.l), 2 ) Previously we reported the results on defect 119 Sn arising from theEC decays of 119 mTe doped radiochemically into Se metal and SnSe. 3 ) This year the final statesof recoil 119 Sb and 119 mTe atoms produced in p- and a-irradiated SnSe have been studied.
Tin isotopes enriched in 120 Sn (for p-irradiation) or 117 Sn (for a-irradiation) were used for
preparation of SnSe samples in order to. minimize the resonant self-absorption of ')'-rays in thesources. A stoichiometric mixture of 120 Sn or 117 Sn and Se metals was fused under Ar to prepare
SnSe and 117 SnSe. Powder of the SnSe samples was irradiated on an aluminum plate cooledwith water by 16 MeV protons or 38 MeV a-particles. Mossbauer emission spectra of theirradiated samples were measured against a BaSn0 3 absorber at 78 K. Measurement of the a119
mTe
irradiated 117 SnSe was performed after a radioactive equilibrium had been attained between
120

and its daughter 119 Sb.
The emission spectrum of p-irradiated 120 SnSe (Fig. 1) was essentially the same as the119
Sb areabsorption spectrum of normal SnSe. This indicates that the 119 Sn atoms arising from
119
Sb is
located in the Sn site of SnSe. Since the recoil energy associated with the EC decay of
119
119
Sb remain in
Sn atoms arising frommuch smaller than the displacement energy in solid, thethe original position of 119 Sb after the decay .1)

It is concluded, therefore, that the energetic

100

~

.b
(f)

c

2c
(1)

::::
cu
w
-+-'

0::

92

-3

3
0
Relative velocity ( mm/ s vs BaSnO 3 at 78K)

6

119Sn-Mossbauer emission spectrum of p-irradiatedFig. 1.
120 SnSe.

99

SnSe2

1

-3

0

SnSe

n

3

6

Relative velocity ( mm/ s vs BaSn03 at 78K)
119
Fig. 2.
Sn-Mossbauer emission spectra of a-irradiated 117 SnSe(a) before and (b) after 1h annealing at 600°C. The arrows show
the absorption lines of normal SnSe and SnSe 2 .

recoil 119 Sb atoms produced by the 120 Sn(p , 2n) 119 Sb reaction were stabilized in scarcely
perturbed Sn site of the SnSe matrix.
As shown in Fig. 2(a), a-irradiated 117 SnSe gave a complex emission spectrum completely
different from both the absorption spectrum of SnSe and the emission spectrum of the radiochemically prepared SnSe( 119 mTe) source. 3 ) It was decomposable into three Lorentzian lines(designated hereafter as Ll-L3 from the left to the right). The emission lines could be hardly
assigned on the basis of isomer shifts for the absorption lines of SnSe4 ) and SnSe 2 . 5 ) A drasticchange in the position and the relative intensity of each line was observed by thermal annealingof the samples after irradiation. With the elevation of annealing temperature, the relative
intensity of the L2 and L3 peaks increased in parallel and, at the same time, the two peaks
moved closer to each other, the center of the two peaks remaining almost unchanged. The peaks
gave finally the quadrupole doublet of 119 Sn in the normal Sn site of SnSe after 1 h annealing at
600°C (Fig. 2(b)). From these observations, the lines L2 and L3 in Fig. 2(a) are ascribed to aquadrupole doublet of 119 Sn in Sn site of SnSe with an unusual distortion in the Se ligand
configuration. The line L 1 became smaller by thermal annealing, disappearing completely after
1 h annealing at 600°C. The line is assigned to an ionic tetravalent tin in a defect structure. It
is interesting to note that the chemical state of 119 mTe produced by the a-reaction in SnSe ismuch different from that of 119 mTe introduced radiochemically into the same matrix, even after
thorough annealing.

100

References
1)
2)
3)
4)
5)

F. Ambe, S. Ambe, H. Shoji, and N. Saito: J. Chern. Phys., 60, 3773 (1974).
F. Am be and S. Am be: ibid., 73, 2029 (1980).
S. Ambe and F . Ambe: IPCR Cyclotron Progr. Rep., ll, 109 (1979).
V. Fano and I. Ortalli: J. Chern. Phys., _§__!, 5017 (1974).
L. N. Vasile'v: Izv. Akad. Nauk. SSSR. Neorg. Mater., 13, 1752 (1977).

101

8. RADIATION CHEMISTRY AND RADIATION BIOLOGY

8-1.

Inactivation of Ribonuclease A

1n Solution by N-lon Beam

Y. Hattori and F. Yatagai

Work aiming at the characterization of the damage on biological substances by high-LET
particles has been continued. In order to reveal detailed nature of radiation inactivation of
enzyme, heat sensitivity of ribonuclease (RNase) A (EC 2. 7 .7.16) solution irradiated with
N-ion beam has been studied. The irradiation was carried out using the biological irradiation
apparatus described previously _1) The accelerated N-ion beam emerged through the vacuum
window of 20 Jill AI foil. Samples of aqueous solution of RNase A (crystalline preparation of
Sigma Chemical Co. 5 X 1o- 6 M) were irradiated in the glass vessel 2 ) through its Myler film windowat room temperature in the presence of air under agitation.

N-ion beam energy at the position

of Myler film was 4.6 MeV /amu.
Irradiated RNase solutions were subjected to the assay of residual activity according to themethod of Anfinsen et ai., 3 ) before and after heating at 60°C for 15 min. RNase A is heat-stable
and the activity loss of unirradiated sample solution by this heat treatment was found to be lessthan 10% of the initial activity.

The activity loss by heating increased for the irradiated enzyme

solution, showing the formation of heat-unstable molecules by the irradiation.
Figure 1 shows logarithmic plot of the residual activities of the irradiated enzyme solutions
after the heat treatment versus those before the heating. Positive correlation is seen between theabove-mentioned two indices of inactivation (coefficient of correlation: 0.76). The data indicatethat the increase in inactivation of RNase A molecules by N-ion beam is accompanied with theincrease in rate of latently damaged molecules which are unstable against the heating.
100 r-r-,--,-~---,---,----,--~---,---r,--,
c:
0

• •

•

•
•••

Fig. 1.
Logarithmic plot of the residual activities
of N-ion irradiated RNase A solutions after heatingof 60°C for 15 min versus those before heating.
RNase A: 5 X 1o- 6 M. Abscissa: residual activity before
the heat treatment expressed as per cent of theunirradiated sample; ordinate: residual activity after theheat treatment (irradiation + heating) expressed as per centResidual activity after irradiation ( %)of each irradiated sample before the heating.
three experiments.

Data from

References
1)
2)

F. Yatagai and A. Matsuyama: IPCR Cyclotron Progr. Rep., !]_, 118 (1979).
Y. Hattori, F. Yatagai, and A. Matsuyama: ibid., p.l20.

3)

C. B. Anfinsen, R. R. Redfield, W. L. Choate, J. Page, and W. R. Carrol: J. Bioi. Chern.,
207, 201 (1954).

102

8-2.

Inactivation of Cultured Normal Human Fibroblasts,

IMR-90, Cells

with Nitrogen Ions Accelerated in the Cyclotron

I. Kaneko, T. Ohno , K. Nakano , and F. Yatagai

Irradiation with high charged particles is supposed to be advantageous in therapy of solid
tumors since it is characterized by an improved depth-dose distribution, efficient relative biologicaleffectiveness, reduction in oxygen enhancement and reduced occurrence of sublethal damage repair.
Although many investigations have been made on cell inactivation with high-LET radiations, it isstill obscure whether normal human cells have any ability to recover from potentially lethal
damage (PLD) after irradiation with high LET particles.
Most of the radiation inactivation experiments have been performed with established cultured
mammalian cells.

Radiobiological studies with diploid cells are frustrated by the low cloning

efficiency of the cells in normal culture media and variation in the cloning efficiency with factors
such as cell density.

"Feeder cell" technique was used to improve and standardize the cloning

efficiency of diploid fibroblasts derived from normal human tissue.
Normal human lung fibroblasts, IMR-90 cells, were maintained as described previously 1 ) in
the medium TOM-H , an improved MEM for human cell culture , containing 10 % fetal bovine
serum (FBS) .

The cells at 28-32 population doubling level were used throughout theexperiments.

Two to three days before the irradiation, the cells were seeded onto a cover glassof 15 mm diameter that was fixed with silicon grease in small glass petri dish of 20 mm diameter.
Ten to twenty thousand cells suspended in 0.2 ml medium were quietly delivered onto the coverglass.

For experiments to examine potentially lethal damage repair , ten thousand cells in 0.2 m£

medium were delivered onto the cover glass.
incubator until the day of irradiation.

The dish was incubated in a humidified C0 2 -He La S3 cells grown in MEM containing 10 % FBS wereonce washed with Ca+t and Mg+t free Dulbecco's phosphate buffered saline , trypsinized and kept
as a suspension in an ice bath.

This suspension was irradiated to a dose of 5500 rad with 6°Co')'-rays at a dose rate of 99 rad per minute to serve as feeder cells.

Although HeLa cells havesmaller potential for supporting colony formation of IMR-90 cells than normal fibroblasts, theuse of HeLa cells made it easier to discriminate the smallest IMR-90 colonies (50 cells peraggregate) from the back ground feeders.
After irradiation with N -ion beams or 6° Co ')'-rays, the cells were kept in an ice bath before
replating .

One hundred and fifty to three thousand IMR-90 cells were mixed with thirty

thousand inactivated He La cells and seeded in to a 6 em plastic dish with 10 ml? of TOM -H
containing 10 % FBS.

The cells were cultured for two weeks.

The maximum inoculation ofirradiated IMR-90 cells was restricted to three thousand cells per dish to avoid additional feeding
effects by IMR-90 cells themselves.
Chinese hamster V-79 cells were cultured and irradiated as above.
were used for their colony formation.

However, no feeder cells

MEM containing 10 % FBS was used for culture ofChinese hamster V-79 cells.
Cells cultured on the cover glass were washed with Dulbecco's phosphate buffered saline(PBS+). The cell layer was covered with a poly carbonate film (5 J.Lm in thickness) wetted with

103

PBS+ to minimize the effect of 8-rays generated during the N-ion irradiation. The small dish withthe cover glass was then wrapped with sterilized polycarbonate film (6 11m in thickness) to keep
moisture and sterility. Cell-handling procedure for the irradiation was similar to that described
previously 2 ) except the usage of a cover glass of 15 mm diameter. A new appratus was used toirradiate the cells with the beam elastically scattered at some angle by a scattering foil. 3 )The survival curve of IMR-90 cells was exponential throughout the dose range for theirradiation with N-ion accelerated in the cyclotron (4.6 MeV/amu at the sample). The small
shoulder region was obtained by calculation of the linear regression of the whole data obtained
from repeated experiments. However, this region was 95 % confidence limit of the regression
line. D0 , DQ' and the extrapolation number were 109 rad, 14 rad, and 1.1, respectively.
When the confluent monolayer of IMR-90 cells was irradiated and incubated before replating,cell damage increased for two hours after the N-ion irradiation and then it recovered to the level
just after the irradiation. This pattern of recovery was also observed in Chinease hamster V-79
cells and apparently different from the known pattern of the recovery from potentially lethal
damage after the -y-ray irradiation.

References
1)
2)

T. Ohno: Mech. Age. Dev., !1_, 179 (1973).
Y. Yamawaki, F. Yatagai, I. Kaneko, K. Sakamoto, S. Okada, and A. Matsuyama: IPCR
Cyclotron Progr. Rep., 10, 36 (1976).

3)

F. Yatagai and A. Matsuyama: ibid.,!]_, 118 (1979).

104

9.

RADIATION MONITORING

9-1.

Routine Monitoring

M. Koyama, K. Igarashi, I. Usuba
S. Fujita, and I. Sakamoto

Results of routine radiation monitoring carried out on the cyclotron from April 1979 to:March 1980 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 1o- 6 11Ci/cm 2 on the floor of cyclotron roomand the underground passage, and below 10- 7 11Ci/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 1o- 7 11Ci/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 JJ.Ci/cm 3 .
(2) Drainage
The radioactive concentration of the drain water from the cyclotron building was found to beof the order of 10- 6 -10- 7 J.1Ci/cm 3 • The total quantity of activities in the aqueous effluents inTable 1.

Annual exposure dose received by the cyclotron
workers from April 1979 to March 1980.
Number of persons

Workers

Operators
Nuclear physicists
Accelerator physicists
Physicists in other fields
Nuclear chemists
Radiation chemists
Biological chemists
Health physicists

Collective

Dose

10-100101-300

>300

dose

undetectable(mrem)(mrem)(mrem)(man-mrem)

5
9
15
2
2

370
130
590
320
880

6
6
4
5
4

2

7
2
Total

Average annual dose per person: 31.4 mrem .
Maximum individual annual dose: 420 mrem.

2290

105

this period was about 60 11Ci, and the radioactive nuclides found by the )'-ray spectrometry weremainly 65 Zn, 57 Co , 58 Co and 75 Se.
(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 2290 man-mrem, while those owing to thermal andfast neutron exposures were too small to be detected. The collective dose to the cyclotron
workers is about 90 % of the value in the preceding period.
In this period the dose to the cyclotron operators was 370 man-mrem, which was 16.2 % of
the dose of cyclotron workers, and the maximum individual annual dose was 120 mrem.

106

9-2.

Leakage-Radiation Measurement at the Underground Passage

I. Sakamoto

Leakage radiation during operation of the cyclotron at the underground passage of thecyclotron building was measured . Leakage dose received from April 1979 to March 1980 by-y-ray and neutron film badges which were left at the underground passage , is shown in Table
1. The machine time allotted for deuteron acceleration was 8 h in March.
Table 1.

Leakage radiation dose (in mrem) at the undergroundpassage from April 1979 to March 1980.

2

Radiation')'-rays (mrem)
Thermal neutrons (mrem)
Fast neutrons (mrem)
Total (mrem)

1870
500
510
2880

* See the figure shown below.

I

Experimental area ( L):

:I 2 X --L--.....t-.-..,_.,...,..,..,-...JI

I
I

Undergroundpassage~
I
I

WT

Control ro om

810
220
580
1610

107

As to the dose values at point No. 2 measured every month, the maximum dose of 760 mrem
was observed in October. In this case, the values of gamma dose, thermal neutron dose and fastneutron dose were 420 mrem, 110 mrem and 230 mrem, respectively.
The increase of fast neutron was observed at point No. 2 in April, October and February.
The total fast neutron dose measured in the three months was 480 mrem, which was 82.7 % of
the total dose in this period. As a result of investigation, it was concluded that the fast neutron
dose was due to the 22 MeV ~-particle bombardment on a brass slit at about 100 nA in case ofirradiation experiment in the beam course No. 4.

108

10. HEAVY ION LINEAR ACCELERATOR PROJECT

10-1.

Status of RILA C

M. Odera

Almost all of the hardwares of RILAC were installed before the end of March 1980. Somebeam diagnostic elements and the circuits necessary for automatic control of the high power
radio-frequency amplifiers are behind the schedule. It is expected that the latter will becompleted and become operational before the end of 1980. Since minimum number of thediagnostic probes were already set in the beam line and any exacting demand for beam quality has
not been put forward to date, installation of the remaining probes can be postponed until nextyear.
Meanwhile, acceleration test by the first cavity was made. Beams were obtained easily.
Setting and sensing of the parameters of the beam transport system through the central control
console aided by a computer were tried and found fast and reliable in so far as control of thequadrupole and dipole magnets are concerned. Remote control of the radio-frequency amplifiers
will be started early next year.
Subjects of experiments for initial few years have been decided in 1979.

Members in chargeof each subject and the committee of users are arranging the experimental sites and preparing the
instruments. As the central unit for on-line data acquisition and processing, a minicomputer
Perkin-Elmer Model-3220 was purchased and installed in March 1980. Its word-length is 32 bit.
Its memory capacity is 768 kB in IC and is supplemented by two disk memories of 80 MB eachand a magnetjc tape of 1600 bpi. A grazing incidence spectrometer for beam foil spectroscopy
was installed in April. A high-vacuum chamber of the high resolution Auger electron spectrometer
was carried in at August. Tuning and test of the electron spectrometer are in progress. Other
apparatuses will be carried in between Dec. 1980 and Mar. of 1981. Those instruments andelectronics most of which are NIM modules are connected with the on-line computer via CAMAC
system. The interface circuits necessary were designed by a member of the user's group andfabrication is being made by a factory.
The experimental apparatuses which will be installed at each end of nine beam-lines in threevaults are listed below. The designations of the beam-lines can be found in the figure in p. 129
of this progress report.
A-1: A scattering chamber of 1 m diameter for the experiments on nuclear physics.
A-2: A crystal spectrometer for the X-ray measurements.
B-1: A scattering chamber for the experiments on atomic physics.
B-2: A 2.2 m grazing incidence spectrometer and a vacuum chamber equipped with a movabletarget holder for beam-foil spectroscopy.
C:
A scattering chamber for the irradiation of metals.
D-1: A magnet and a goniometer for the measurements of magnetic moments. A scatteringchamber for the particle-'Y coincidence experiments.

109

D-2: An electron spectrometer for measurements of the electron emission from metal-surfaces.
E-1: An irradiation chamber for the study of the radiation biology.
E-2: A high-resolution Auger electron spectrometer.

110

10-2.

Control System

T. Kambara, S. Takeda, and M. Odera

Status of hardware
1.
part of the control system including the minicomputer (HP~1000) was installed in November
greaterThe
1979.1) Some control devices, such as off-line control panels for the ion source and a panel for on-line finetuning of analog parameters, were added to the control console in 1980. The latter panel has three sets of shaft
encoders and gas discharge character displays which are linked to the computer via a microprocessor. Figure 1
shows the layout of the console.
During last year, the CPU, mass storage (magnetic tape and disc) and CRT terminals have worked well withfew failures, but the control and measurement interface (HP2240A/41A) and the serial data link have failed more
frequently. In most cases of failure, we replaced the circuit board concerned and the system recovered normal
operation.
At present, more than 40 magnet power supplies distributed in the linac vault are linked to the computer.
The magnet currents are remotely controlled by reference voltage signals (set-points) which are proportional to thedesired currents and are supplied from digital-to-analog converters (DAC's) in the data stations. The control anddata processing of beam emittance and profile monitors are tested using the computer.
Vacuum pressure
monitor panel\

CharacterC~T terminal

A

Control panels of
Ion\ II \\
lj
I

_\ \

[

'

Cont ro I pane I f~e tuning

IJ
'

I

1

Character / Graphic
CRT terminal

'

I

""' ~

I
[

I IJ
,

L

I

I

I

I

I

I

Keyboards

Fig. I.

Front view of the control console.

Software development
2.
The programs for the operation and test are developed and executed under the RTE-IV operating system.
Some programs for the beam monitors are written in Assembler, while all others are written in FORTRAN. The
operation of the magnet power supplies is done as described below.
( 1) Start of operation
We use one of the two CRT terminals in the console for the operation. When the program is started, thecomputer checks the serial data link and the HP2240A/41 A's and then asks us the name, mass, charge andacceleration conditions of the ion. When we input these parameters from the keyboard, the computer calculates
and stores predicted values of the magnet currents, then it is ready for display and control.
(2) Display of parameters
Because there are many parameters to be displayed and controlled, they are devided into groups called111

pages. Up to nine parameters can be put in a page in any combination. We select any page by inputting the page
number from the keyboard. On the CRT screen , a table is displayed which contain the name , status informations
and numerals such as predicted values from the calculation, present set-point values and measured values of theparameters in the page. The numerals are displayed in the engineering units. We can update the informations
on the CRT by pressing the RETURN key . The responce time including the measurement, data transfer,conversion and display is about 2 seconds at maximum . Most of the time is spent in the data transfer on theserial data link.

Figure 2 shows an example of the table displayed.

~ AMF OFlO N: AR
Z= i8
MASS= 40
M/ Q=1 3 . 33
FREQ.=.O OO OMH ZPACE 10:N(:lMEIN J .
I< lJ

DDt·-·1.

DQ'I-:.:.~

A

(1

DK

Dl< CIN
C:r:~ I_C .

----- -- -PRES ET.00-

NE: x:Tr I 1'1F

5 7.9651.35- - ---

NO.

5 1. 52

Ht-1::)i·'i

i:~

1 1 7 . 41

I:':")'? I 9 '.'/

117 . 4 0

T i~ i ... 1

11 6 . 2 7~)t.44ii6.26- - -- - +------

ii 7 .3S
4

~-':

i?

*

l~M :1.

1 ?:c1 : ~:: sTUi··· i:!

44.0?
----- -- - - - - - --- - - - ---f- -----f------- --- - ---... i . . () 0OK?

l:l p [ ')I f~ j) [YCll< [) ('-)

CJN

Si.44

':) 0 0 . () 0---

INFl l.JT' ) [ ()NP F~INTIN J ECT OR P AR AMETE RS .

UNIT

I- -

P P F~:;r::: T

1 1 '/ . 4]

51 . 37

If '~· ' 0 (I-----r--- - --- - - - - -1--- - - - -11 6 . 5 4r·(:,:..-:·
1

t :'!. 6 ' :-? 7

l":")i. '<~4

44.09

*

*

01<

Fig. 2.

Example of table displayed on CRT scree n.

(3) Control
We can change the magnet currents as listed below:i)

We can set all the set-points in the page to the predicted values from the calculation, or set them tozero as long as they are controllable from the computer. Only we have to do is to press a few of the eightprogrammable keys on the keyboard.
ii)
We can select any parameter in the page separately and input the set-point with the numerical keys
on the keyboard.
iii)

We can select up to three parameters and change their set-points almost continuously by turning theshaft encoders on the panel for fine tuning.

The panel is set between the two CRT terminals.

This method isuseful in finding the best beam transport condition starting from the calculated values as the first approximation.
In any case , the computer checks whether the input values are within certain limits , converts them to the
output values to the DAC's and sends them to the data stations . Because the magnet currents are changed
stepwise and rather slowly, it takes about 6 min to set all the magnet currents to the specific calculated values.
3.
Improvement and expansion plans
The circui~s and the wiring for the on-line control of the RF system have beer.· ordered to the contractor
and will be completed by the end of 1980. We will connect one of the data stations in the linac vault with thecomputer by an optical fiber HP-IB link, instead of the present serial data link. We expect to improve thedata transfer rate in this way.
Figure 3 is a block diagram of the control system after the above modification is done .
We are planning to monitor other parameters such as vacuum pressure or beam current outputs from slits
and stoppers by the computer . Monitoring of these parameters will be necessary in future for closed loop
operation of the linac.

112

Control console

stationThree other stations

Fig. 3.

Block diagram of the control system after themodification mentioned in the text.

Reference
1)

T. Kambara, S. Takeda, and M. Odera: IPCR Cyclotron Progr. Rep., !]_, 134 (1979).

113

10-3.

Design of ECR lon Source

M. Yanokura and M. Odera

Development of an electron-cyclotron resonance (ECR) ion source has been started to get
multiply charged ions. For this type of ion source, there is no need of arc and heater power
supplies on the high voltage platform. There is no problem of electrode corrosion due to arcs,
since there is neither cathode nor anode which may cause discharge. Therefore, the ECR ion
source has inherently a long life, and can be operated in CW mode. On the other hand, the ECR
ion source requires high magnetic field and micro-wave power.
As the first step of development, a single stage ECR ion source was designed. A schematiccross section of the ECR ion source is shown in Fig. 1. A pair of solenoidal coils has been
constructed. Each coil consists of 112 turn hollow-conductors. A soft-iron return yoke wasincorporated to save the electrical power for coils and to decrease the leakage of magnetic flux.
Measured axial magnetic fields are shown in Fig. 2. Currents of the coils are given in amperes.
When the same current is fed to two coils, mirror ratio or maximum to minimum fields ratio is
about 1.78. Maximum field was increased by about 50% by incorporating the return yoke.
Strength of the magnetic field was found to be proportional to the coil current up to 100 A. The
magnetic field of 877 gauss is required as the resonance field at 2.45 GHz. The current of 140 A
is obtained to get this field strength by the extrapolation of the data mentioned above. In thiscase, the current density in the conductors is 1.9 A/mm 2 and the power dissipation becomes
460 W per coil.

~@
L- ~4~~0----------11
ECR ion source test-stand.
Fig. 1
1. wave guide, 2. faraday cup, 3. extraction electrode, 4. ECR cavity,
5. flange, 6. pumping port, 7. gas inlet, 8. pumping port. 9. coils,
10. return yoke.

114

700~------~-------.------~

80-40
600
500
Vi

~ 400

ro

tlO

u
:.::::;
Q)

c

~ 200

~

Fig. 2.
Position ( mm )Axial magnetic field of thecurrents in Ampere.

A cavity for ECR plasma containment is under construction. Total length of the ECR ion
source test-stand is about 1200 mm. Dimension of the cavity is 206 mm in diameter and 200
mm in length. A diffusion pump of 1500 f/sec is used to evacuate the cavity. The gas pressureis estimated to be less than 1o- 4 Torr when the source is operating. Micro-wave power is fed
to the cavity through a vacuum window at the exit of a wave guide power feeder. The wholevacuum components including the cavity are made of stainless steel.

115

10-4.

System for Beam Monitoring with Beam Slit and Stopper

M. Kase, I. Yokoyama, and M. Hemmi
About 30 sets of beam slit (SL) and beam stopper (BS) devices are installed along the beamline of the linac. Beam current signals from these devices give a rough estimation of beam
intensity and profile. The indication of these information on the control desk panel is often
required for the machine operation.
Figure 1 shows the beam monitoring system using the SL and BS apparatuses.
Slit sizes of the SL devices, in general, are manually adjusted. However, horizontal slit
widths can be remotely adjusted for some SL instruments which are installed in the low energy
beam line between the injector and the first cavity. More compact and simpler SL instruments(used as beam baffles) , whose slit sizes are fixed, are installed in each space between theacceleration cavities.

5 Analog signals
Linac vault
Control room------ - -- ----- - ---Control deskFig. 1.
Bus line

Block diagram of beam

monitoring system using beam slits(SL) and beam stoppers (BS).

The BS device is typically set up with the SL system in one vacuum chamber, called slit box.
Copper plates of the BS devices are plunged into or pulled out from the beam course swiftly by
pneumatic cylinders which can be remotely driven by BS controllers. Some BS controllers areconnected with the interlock network in order to protect persons or instruments from operator's
mishandling.
Five analog signals of beam currents from one set of SL and BS are led to the amplifiersystem mounted in a rack in the control room through five coaxial cables bounded in a wire
braid tube together with some control lines. By de amplifier the current signals are linearly
converted to low-impedance voltage signals, whose magnitudes are always kept between 0.1 to
1.0 V for any beam intensity from 1 nA to 100 J.LA by automatic gain control circuits. The
beam currents at all SL devices are separately indicated on the analog meters together with meterfull-scale values. At the amplifier system, in addition, one can drive any BS devices and the beam
current at the BS is also read in the same way.
Four SL signals, one BS signal and some digital signals can be sent from the amplifier system

116

to the control desk via bus lines. If an operator pushes the button on the control desk panel
corresponding to the SL instrument which he wants to monitor, then the beam currents at the
selected SL are indicated on the analog meters on the panel together with meter-full-scale values
and the corresponding SL address. And it also becomes possible for the operator at the control
desk to control and read the BS device installed just behind the selected SL instrument.

117

10-5.

Acceleration Test of the First Cavity

M. Kase, M. Yanokura, Y. Chiba, and T. Tonuma

The beam acceleration test by the first cavity was started in the spring of 1980. It has been
confirmed that N+ ions were successfully accelerated. In this report , we give a summary of theacceleration test.
1
The N+ ions, which were produced in an axially extracting PIG ion source ) and accelerated
by the injector de voltage, Vinj ' were introduced into the first cavity. The ions were thenaccelerated by the rf acceleration voltage across drift tube gaps , V rf- The conditions ofacceleration are listed in Table 1. In order to examine the beam acceleration, it is necessary to
Conditions of acceleration.

Table 1.
Ions

N+

Injector voltage, Vinj
Beam current at the entrance to thefirst cavity

310 kV

Acceleration frequency

20 MHz128 kV (peak value)

Acceleration voltage, V rf

200 nA (de beam)measure the beam energy. However it was not available to measure the beam energy after the
first cavity by a magnetic field or directly by an SSD in the beam path. So we employed anindirect method: to know the beam energy from the energy spectrum of the beam scattered bya thin Au target. The arrangement of the apparatus and the block diagram of the electronic
The Au target 20 JJ.g/cm 2 in thickness was prepared by the vacuum
evapolation on a polycarbonate film. The energy calibration was performed by means of theinterpolation using 500 ke V and 1 MeV nitrogen ions from the injector and 5.48 MeV alphacircuits are shown in Fig. 1.

particles from 241 Am.
SSD

J----- - Magnet

for electron supression

Au target~

7¢ co llrmator

Poly carbonate film

Fig. 1.

Arrangement of the apparatus and block diagramof electronic circuits.

118

104

269keV - - - - - - - - - - - - ,·.·~1.42 MeV

*

0

20

40

Fig. 2.
Pulse height distribution for nitrogenions scattered by a Au target at the scattering
angle of 110° in the laboratory system.

60
Channel number

Table 2. Observed and calculated values of the beamenergy and its spread.
observed value

calculated value

1.8 MeV82 ke V (fwhm)

1.86 MeV
112 ke V (full width)

4 .5 %

6 %Figure 2 shows a typical example of the pulse height distribution for the scattered nitrogenions. We can see a peak at 1.42 MeV due to the ions accelerated by the first cavity. The mostprobable energy of the accelerated N+ ions, Emp ' is determined by considering the kinematics
of N-Au elastic scattering and the peak displacement caused by the energy loss in the Au target.
Furthermore , the energy spread , ~E , can be obtained by subtracting the contributions of thetarget energy loss and its straggling from the observed peak width. These values are summarizedin Table 2 together with the values calculated in the way described in Ref. 2.

The agreement
between observation and calculation are satisfactory if the errors in the measurement and thesimplifications made in the calculation are taken into account. The beam intensity of N+ ions
irradiating the Au target can be estimated from the peak yield using the Rutherford formula.
Consequently , the beam current of N+ ions sufficiently accelerated by the first cavity is evaluatedto be 4 X 10_: 9 A on the assumption that it is a uniform beam of 30 mm diameter. The ratioof the accelerated beam current to that injected into the first cavity is about 0.02. The transport
efficiency of the first cavity for de beam has an upper limit of about 0.2 which is estimated fromthe phase acceptance of the cavity. The obtained value , however, is much smaller than this limit.
The difference may be due mainly to the insufficient adjustment of magnetic fields of the triplet
quadrupole magnet set in front of the cavity and each quadrupole magnet inside the drift tube.

119

A better adjustment of the magnetic fields and use of a beam buncher will improve this ratio.
As seen from Fig. 2, there is another peak in the lower energy region. It is supposed that
this peak corresponds to 310 keY neutral nitrogen atoms produced in the beam path between thesecond deflecting magnet (BM2) and the first cavity through the electron capture reaction of
nitrogen ions with residual gas.
By changing the acceleration frequency from 20 MHz to 24 MHz, we obtained 2.6 MeV for
theN+ ions. In this case, Vinj was 460 kV and Vrf was 162 kV (peak value). No difficulty
was met in changing the parameters. The measurement of the beam energy was made for thisparameter set with the same arrangement as shown in Fig. 1.

References
1)
2)

S. Nakajima: IPCR Cyclotron Progr. Rep., 11_, 141 (1978).
T. Tonuma, F. Yoshida, and M. Odera: Reports I.P.C.R, (in Japanese), iL 53 (1975).

120

10-6.

Design of RF Control System

Y. Chiba

The IPCR heavy ion linear accelerator includes six pairs of main resonators and power amplifiers; they
are required to he continuously tunable from 17 to 45 MHz. 1), 2 )An RF control unit is provided for each pair.

Figure 1 shows a block diagram of the unit.

of the unit are controlled by the control processor of the accelerator control system. J)

All functions

The power amplifiercoupled with the main resonator is shown schematically in Fig. 1 of another report in this volume. 2 )It hasseven adjustable devices ( CD - CD in Fig. 1) for tuning and six terminals (a - fin Fig. 1) to supply RF sample
signals to the control unit.

a, d-f RF sample pickupsb
Directional coupler (forward )Directional coupler (reflected )cCD - CD Driving motors for adjustabledevicesCD
Shorting devi ce(2)Large trimmer capaci tor(]
Smal l trimmer capacitor@
Coupling capacitor®
Vacuum vari able cap acitor®
Plate stub(l)
Grid stub

MIX Mixer
LPF Low pass filter!FA IF amp.
LA
Limiter amp.
REC Rect ifier!PC IF phase comparator
BA Buffer amp
1/ n 1/ n count down circuit
EVD Electronic variable delay
RPC RF phase comparator
ITA Integrator amp
VCO Vo ltage controlled oscillator
PAT PIN diode attenuator
SY Synchronize gate
PCD Preset counter delay
ACA Amplitude control amp.

Ref. RF
fo=l7- 45MHz

Local
RF

SB
AD

Subtract amp.
Add amp

DIV Analog divider
PSA Positioning servo amp .
MC Motor controller
DMP Demul t ipl exer
CM Control memory
A/ D Analog to digital converter
MPX Mult iplexer
3 ch. analog voltages- - DC Ref .
FromcontrolCMproces- 16
brts
brts
sor
4
8 ch. rei ay outputs ~{12{gliMP }~~ntrol

Fig. 1.

Block diagram of RF control unit.

121

1)

RF processing

Six RF samples from the pickups and the directional couplers and an RF reference signal are mixed
with signals generated by a local oscillator and are converted into intermediate frequency (IF) signals of 50 KHz.
The RF reference is distributed to each RF control unit from a synthesizer through lines of equal electricallength.

A definite phase relationship between the units is established in this way.

is also distributed from a common source.

The local frequency signal

After amplification, a part of the IF signal is rectified to givean amplitude output, and the other is converted into a square wave keeping phase information in its risingand falling edges.

A pair of square waves is applied to a phase comparater to obtain an output proportional

to their phase difference.
The IF signals from the two directional couplers are added to or subtracted from each other and converted
into IF signals proportional to voltage and current on the feeder at the front end: point A in Fig. 1. They
are applied to a phase comparator and, after being rectified, to an analog divider.

Their outputs represent

angle and magnitude of impedance Z: input impedance of the resonator seen from the front end of the feeder.
2)
Auto-tuning feed back loops and positioning servo loops
There are four auto-tuning feed back loops, loop A to D; one of them, loop B, may be better called
auto-impedance matching rather than auto-tuning loop.

The tuning scheme of each loop is described byitemizing in the following: item 1 is the aim of the loop; item 2 describes a variable used to detect tuning
error of the loop; item 3 gives the value which the variable takes at the exact tuning point; item 4 are thenames of adjustable devices of the loop. Each loop is composed to keep the variable to the value specified initem 3 by trimming the adjustable device.
Loop A.
1) Tuning of the main resonator. Two schemes, P and Q, are selectable; scheme P responds
to wider deviation of tuning but the value mentioned above has a slight frequency dependence.

2P) Phasedifference between RF voltage in the main resonator and that of the front end of the feeder. 3P) A valueslightly less than 90 deg. 2Q) Angle of the impedance Z. 3Q) 0 deg. 4) The small and large trimmer
capacitors.
1) Impedance matching between the main resonator and the feeder.
Loop B.
impedance Z. 3) 60 n. 4) The coupling capacitor.

2) Magnitude of the1) Tuning of the plate circuit of the 4648. 2) Phase difference between plate RF voltages
Loop C.
of the 4648 and the 3CX3000. 3) 180 deg. 4) J'he plate stub.
Loop D.

1) Tuning of the grid circuit of the 4648.

RF voltages of the 3CX3000.

3) 0 deg.

2) Phase difference between plate and cathode4) The grid stub.

All auto-tuning loops are locked out unless RF level in the main resonator is normal.
Loop A and B interfere with each other and loop C.

For avoiding excursions of the loops caused by theinterferences, loop B is activated only when loop A stays in the neighborhood of the tuning point.

Similary,

loop C is interlocked to loop A and B.
An adjustable device is preset to a given position by the servo loop comparing reference voltage with theoutput of the position potentiometer. Two reference voltages are used. One assigns the positions of three andanother four devices. Selection of run or halt and selection of the servo loop or the auto-tuning loop are
decided for each device independently according to the commands from the control processor. The shorting
device for coarse tuning of the main resonator and the variable vacuum capacitor for adjustment of plate load
resistance of the 4648 have the servo loops only.
3)

Phase and amplitude regulation

After the square wave from the resonator is delayed by preset counts of 25 MHz clock, its phase iscompared with that from the RF reference.

The output of phase comparator controls an electronic variabledelay, inserted in to the loop of a phase locked oscillator locked to the RF reference, so as to keep the output
null.

Thus the RF phase of the main resonator is fixed at any position ranging ±180 deg. or more against

the reference by changing the preset counts; a count corresponds 0.72 deg.
An RF amplitude stabilization loop compares the amplitude output from the main resonator with areference voltage and drives a PIN diode attenuator controlling the input RF level of the power amplifier.
loop also includes a pulser to enable breakthrough of multipactoring by pulse RF excitation and protection
circuits for the final tube.

This

122

The expected stabilities are ""' 1 X 10- 4 for amplitude and less than ±0.5 deg. for phase.
For initial tuning at an operating frequency, the control unit searches rapid growth of RF voltage in themain resonator by moving the trimmer capacitors around preset positions together with pulse RF excitation.
4)
Computer control
The control processor sends following control informations to each RF control unit: Three channelsof analog voltage, 0 - 10 Vat 10 or 14 bits resolution ; eight relay contact outputs; parallel 16 bits of TTL logic.
Two channels of analog voltage are used for the reference of positioning and one for the reference of
the RF amplitude in the main resonator.
Four relay outputs turn on and off four groups of the power supplies. Next one makes resetting theoverload protection , and another one controls the tap changer of the plate power supply of the final tube.
The 16 bits parallel data are used as four bits address, including one spare bit, and 12 bits control data.
They are stored in 8 words control memory of 12 bits length ; total number of control bits is 96. Each bitof the memory is assigned to a proper control function. For example, preset counts defining the RF phase
occupies ten bits.
The maximum 96 bits of status informations in the RF system are transformed into 8 channels of 12 bits
length by a multiplexer. A word of 16 bits length formed by joining 4 bits channel address, including one
extra bit , to 12 bits data is transmited to the control processor. In the 96 bits, outputs of two 8 bits A/D
converters each having 16 analog channels are included for analog informations.
For maintenance aim, it is possible to operate all the functions of the control unit from the local panelof it instead of the control processor.
A simplified version of the RF control unit is used for the buncher and the chopper.

References
1)

M. Odera: IPCR Cyclotron Progr. Rep. ,], 140 (1973).

2)
3)

T. Kubo andY. Chiba: ibid., 14, 123 (1980).

T. Kambara, M. Odera , and S. Takeda : ibid., 12 , 131 (1978); !1_, 134 (1979).

123

10-7.

Measurement for Characteristics of RILAC RF System
and Excitation Test of Resonators

T. Kubo and Y. Chiba

Master oscillator and power amplifier (MOPA) method is applied to the radio-frequency (RF)system of the variable frequency linac (RILAC). 1) The frequency range is from 17 to 45 MHz.
A schematic diagram of the system is shown in Fig. 1.

It consists of one master oscillator andsix power amplifier chains with control circuits 2) which are separately coupled to each resonatorby coaxial feeders. Each power amplifier chain has a solid state amplifier as the first stage, agrounded-grid triode (EIMAC-3CX3000A 7) as the second stage and a grounded-cathode tetrode(RCA-4648) as the final stage.

The resonator is of a A./4 mode coaxial type 3) and has threemovable tuning devices. A shorting plate is used for coarse tuning and two capacitive trimmers
for fine tuning. The feeder is capacitively coupled to the resonator with a disk forming the tipof feeder (coupling capacitor disk).

For getting the impedance matching between the resonatorand the feeder, the coupling capacitance is adjustable by changing the insertion depth of the disk
into the resonator.

The plate- and grid-circuits of the RCA-4648 are tuned by two coaxial stubsof variable length which are indicated as PSTUB and GSTUB in Fig. 1, respectively.

A variablevacuum capacitor (VVC) can vary the load impedance seen by the RCA-4648.
The greater part of the RF system was installed in 1979, except the control circuits which
would be used for the automatic operation. 2)

In 1980, we have started to measure electrical

Ampl. &
phase
controller~ -- -®
PSTUB

-lOmW
Masteroscillator( Freq.
synthesizer)

Zo -8 lQ

GSTUB
17-45MHzI

Zo -81Q

- lm

1

@

r5m

Resonator

Plate power
supplyVmax = 16kV

Fig. 1.

Schematic diagram of the RILAC RF system.

a) Shorting plate,b) Stem, c) Coupling capacitor disk, d) Large capacitive trimmer, e) Small
capacitive trimmer, f) Drift tube, g) - j) Voltage pick-ups, k) Directional
coupler (forward), 1) Directional coupler (reflected), @) Drive Motor.

124

Capaci l ance of WC ( pF )

110 E

150

100

1OOQ

200 250 300

50

20

E

40

/
/

/

150

/

::C

/

~

/

._g

/
/

u

cQ)

35

0.

/

(IJ

/

u

/

100 :5///~---::~ ~ 18

(IJ

/

::::J
CJ

17 MHz

u

/

;>,

/

/

0
:5
0.

c

(IJ

c
0

]
CD JOQ
:::J

()_

\

~ 20

I

\

\

\

22

~ 24

-o

Q)

\\\

\

.........._\~

in

Q)

(f)

0:::

~

~

c
0

50

20

~26

-~~33

36
)/
--=---=---=--=--=--=---=--~
2 40-=;_;:;:_;;>::i:::====:=::::J4i?

0
Posit ion of the shorti ng plate ( mm )

0

45
500

1000
Relative posi tion of VVC

Fig. 2.

Characteristics of the resonator. This
figure is of the No. 4 unit. The solid line shows
the resonant frequency and the dashed line theCharacteristics of theFig. 3.
plate-circuit of the RCA-4648. This
figure is of the No. 5 unit. Solid lines

optimum insertion depth of the capacitor disk.

show the resonant frequencies and

The position of the shorting plate is measured
from the upper limit as illustrated in this figure.
Two fine tuning devices are fixed at the center

dashed lines the load impedances.

of the moving ranges.
characteristics of the RF system and to excite the resonators by the manual operation in order
to confirm the performance.
Before operating the system at high RF levels, the measurements were carried out withrespect to the following items:
1) The relation between the resonant frequency and the position of the shorting plate.
2) The optimum insertion depth of the coupling capacitor disk. The results for the above
two items are shown in Fig. 2. The resonant frequency and the optimum depth were determinedby searching for the condition that the input impedance of the resonator looked through thecoupling capacitor is equal to the characteristic impedance of feeder (60 Q). Under thiscondition , the resonance and the impedance matching between the resonator and the feeder are
attained at the same time.
3) The load impedance of the RCA-4648 and the optimum length of PSTUB to satisfy
the tuning. The load impedance and the resonant frequency for the plate-circuit of the RCA-4648
are shown in Fig. 3 as functions of the capacitance of VVC and the length of PSTUB. In thismeasurement , the feeder was replaced by a dummy load of 60 n to simulate the ideal impedance
matching between the resonator and the feeder.
4) The optimum length of GSTUB to satisfy the tuning. The result is shown in Fig. 4.

125

100

Shorting plate
QJ

E0

::::>
f-

U)

(.9

QJ

::::>

0

U)

..c

f-

(.9

0

bD
c

50

Q)

_j

-

-

..c

bD
c
Q)

_j

To gri d of RCA 4648

0

30

40

Freq uency ( MH z)

Fig. 4.
Characteristics of the grid-circuit of the RCA-4648. This
figure is of the No. 5 unit. The length of GSTUB is measured as
illustrated in this figure.
5)

The calibrations for voltage pick-ups.

The voltage pick-ups are of a capacitive divider

type (see g ""' j in Fig. 1) and work as amplitude and phase detectors.
performed by comparing with the output voltages of standard probes.

The calibrations were
Their frequency

characteristics were found to be almost flat.
In these measurements, an RF vector voltage meter and an RF current probe were used .
Using these data , we have manually operated the power amplifiers at frequencies ranging
from 17 to 30 MHz. The accelerating voltages which were generated in the resonators were
measured by the voltage pick-ups. The energy spectra of the bremsstrahlung X-rays from theresonators were taken at the same time. The calibrations for the voltage pick-ups were checkedby these energy spectra. The maximum voltages described in the specifications 4) have beenachieved for the No. 5 (280 kV) and No. 6 (300 kV) resonators. However, the operation became
somewhat unstable near the maximum voltages by sparkings which occurred in the resonators.
Conditionings were necessary to get the stable operation at high accelerating voltages.
Multipactoring phenomena which occurred in the resonators could be overcome by overcoupling
the amplifiers to the resonators and by pulsing the amplifier driving signals until normal RF
fields were attained in the resonators.
These data obtained will be used for the automatic operation with the control circuits.
The measurement and excitation test for remaining units are in progress.

References
1)
2)
3)
4)

Y. Chiba:
Y. Chiba:
Y. Chiba:
Y. Chiba:

IPCR Cyclotron Progr. Rep.,~' 143 (1979).
ibid., l_±, 120 (1980).
ibid. , lQ, 144 (1976).
ibid. , U_, 141 (1979).

126

10-8.

Magnets for Beam Transport System

M. Hemmi , Y. Miyazawa, and M. Odera

A design of the beam transport system was described in a previous IPCR Cyclotron Progr.
Rep.o This report is confined to the results of measurements of the five dipole magnets installed.
At the beginning of 1980, the magnets were installed in the target area as shown in Fig. 1.
Beams accelerated by the linac are deflected into five directiQns by the switching magnet (SW).
Each beam channel has two target stations except channel-C.

Channel-C may be used, in future,

as a part of the beam transport line leading to the sse which is under construction.
A vertically bending magnet (VM) in channel-E deflects beam to the target station in the lower
floor vault (Target area Ill) .
Table 1 shows characteristics of the magnets. Maximum magnetic rigidity of ions which the SW
magnet can deflect is 3700 kG-em for the beam deflection angles of ±30°. The maximum
momentum of beams that can be bent by the analysing magnets (BA) in the channels A and B
is limited by the magnetic rigidity of 2200 kG-em. For the VM magnet it is 1400 kG-em.
Therefore, it is necessary to use a charge stripper in front of the BA and VM magnets in order todeflect all kinds of the beams accelerated by the linac. Rigidity of the beam can be 3000 kG-em.

': ) .-'

9~ + jTarget area I j~ N

cP·LY'.

r0

n
J

I

I

I

I

Target area IIJ

sw It 7 600

Channel A -1
+ 3o· +'----6=-=-o---1·M-----#- 4----------f!!;l--- ------M--4~-~c=--- - -~- -- L_ __ j
SW

0

2

J

3m

Beam

Fig. 1.

Accelerator roomJ

: Switching magnet

BA- A, B :Analysing magnet
OS : OS magnet
VM: Vertical I y bending magret

OQ: Quadrupo le dublet magret

BaSL: Beam baffle:Slit box

Layout of beam transport magnets .

127

Table 1.

Pole gap
Pole face area (Sp)
Cross-sectional area of yoke (Sy)Ratio of Sy/Sp
Return path length of flux
Number of turns
Cross-sectional area of conductor
Coil current
Current density
Angles of beam deflection(em)(cm 2)(cm 2)

Slant angle of pole boundary
Radius of curvature
Maximum field of magnet
Amperere-tum
Magnetic rigidity(deg.)
(em)
(kG)
(AT)
(kG-em)Characteristics of the magnets.

(em)

(mm2)

(A)
(A/mm 2)(deg.)

SW

BA-A
-B

VM

5
6056
8000
1.32
228
300
0.8 tx86=68 .8

5
4340
6400
1.47
159
300
0.8tx85=68

5
3769
4080
1.08
150
300
0.8tx85=68

5
2043
2226
1.09
138
420
o.sstx85=46.8

200
2.91
0, 12.5, 30-20, - 30

200
2.94
0,60

200
2.94
0,90

80
1.71
-10,+10

0
150
15.1
6xl04
2265

26.5
100
14.1
6x104
1410

0
400
8.2
3.1 xl043280

0250 (±30°)14.3
6xl0 43575

DSFigure 2 shows excitation curves of the magnets. There is no indication of saturation in the
return yokes of DS (the small angle deflection switching) and BA magnets, but a small saturation
effect is seen in the case of the VM and SW magnets. The pole edge of VM magnet is rotated
so that normal to the edge face makes an angle of 26.5° with respect to the beam axis to obtainstigmatic focusing effect.

15~----------~----

Fig. 2.
Current (A)Excitation curves ofvarious magnets.

128

Figure 3 shows various fringing-field distributions of the magnets. The pole corners areshaped so that the magnetic field inside the iron is almost homogeneous. The relative distributionof the fringing field of each magnet was found to be constant within the range of the applied
excitation current , showing the effect of the pole corner profile. The pole gap field were alsomeasured and no effects of corner saturation were seen.

I = 209.5 (A)8o = 14.820 ( kG )- 20 0 20 40

100 120 140 160 180 200 220 240 260 280°

Distance from pol e edge ( mm)Fig. 3. (a) Fringing field curve measured for SW magnet.

1.0
I = 210 (A)Bo= 15.2 ( kG)

0.8::::(;

-o
a;

20

UJ~
~&&,,
302i6

~
....__

0.6
.~

Q)

c

0.4

DC

(\)

E
<V

:::

1U

0.2 a;

0:::0Distance from pole edge ( mm )Fig. 3. (b) Fringing field curve measured for DS, VM ,and BA magnets.

Reference
1)

M. Hemmi, Y, Miyazawa, M. Odera, and T. Tonuma: IPCR Cyclotron Progr. Rep , !1_,
138 (1978).

129

10-9.

Vacuum System of the Beam Transport lines

Y. Miyazawa and M. Hemmi

The vacuum system of the beam transport lines can be divided into six blocks: Those forthe five channels and one for the chamber of switching magnet. Figure 1 shows the layout of thevacuum equipment along the beam transport lines. Each beam channel is provided with a turbomolecular pump (TMP) and a triode sputter ion-pump (IP) having pumping speed of 140 f /sec and120 £/sec for air, respectively.

The chamber of the switching magnet to which the five channels

are joined is provided with a turbo-molecular pump having pumping speed of 450 £/sec . The
vacuum elements for the beam lines are joined with each other by the European vacuum standard(PNEUROP) NW63 flanges and pipes.

A vacuum gate valve is provided at the end of each channel

sepavating the vacuum chambers for experiments from the beam line . It is pneumatically operated
and can be opened only when the pressure in the chamber is below 5 X 10- 6 Torr.

Ta rge t stations

Experimental area

Channel A-1--~co~~.~-E~----~~~~c=-- --u1

--~

-

: __

! ~ -~LJ

JJ_jAccelera tor@ Turbo - Molecula r pump l/ s

@ lon pump l/ s
0

2

3m

---\~' ' , ·, -~-

'-~w·
\__
>

Gate valve® Philips ga uge+ Fl ange connection
11011

SL

D

Fig. 1.

Bellows
Be am slit box

Vacuum system of the beam transpo rt lines.

130

(f)

0.::::::;-

Eo~0

D._.-<

10 - 6
9
8
7
6

_,.-

~ 5

/

~ 4

ct

2

~'""-......

""' ~

/

~

~ 3

Q)

-

\,

\/

I

\

/

Vacuum pressure distribution between
Fig. 2.
pump stations: Solid line was calculated assuming a degassing rate of 4 X 1o- 9 Torr·£/ sec·cm 2
from the surface of the stainless steel pipes.
Closed points are measured values at channel-C.

10 - 70

5

4
3
2
Di stance along the beam pipe ( m)

OCT. 23 1980

10 - 3'-Q)

Channel - B==

$:
0

0.

o.c

I

Eo
~(f)

-

~

10 - s,.§ Jl

~_\\

I

I

:

-L·

~

- _\\

l!

(f)
(f)

.......

Q)

ct• Pressure in the beam pipe
distance l m from Ion pum p
x Turbo - molecular pumpc::. Sputter Ion pump head

O.·

I!.1

"-

..
I

........... X~~

10 - 6

I'-

X

"- ~

-·
--...;;

x_
X-

~

2

3

4

5

r--x

~

10 - 7
0

r-•·

6

7

8

9

Pump - down time (hours )Fig. 3.

Typical pump down curve of channel-B.

Roughing of the beam pipe can be done directly through each turbo-molecular pump by aforepump (340 £/min). When the pressure at the outlet of the turbo-pump falls below 1 Torr,
the turbo-pump can be run to block forepump oil vapor from passing backward through theturbo-pump into the connected system. The power of the sputter ion-pump is supplied when theturbo inlet pressure reaches 5 X 10- 6 Torr.
To avoid the beam loss due to the charge exchange reactions between heavy ions and residual6
gas molecules, the required mean pressure in the beam pipe should be below 1 X 1o- Torr.
Therefore , turbo pumps or sputter ion pumps were needed to be distributed along the beam line
7
at every 5 meters. The vacuum obtainable at the pump inlet is 1 X 10- Torr without baking

131

treatment. The pressure at half way between pumps rises to a value three times of that at thepump head. Figure 2 shows the pressure distribution along the beam line calculated assuming
the outgassing rate of 4 X 10- 9 Torr-£/sec·cm 2 . The outgassing rate in the channel-A obtainedby a pressure rise test is about 1 X 10- 10 Torr·£/sec·cm 2 . Figure 3 shows a typical pump down
curve measured for channel-B. The required pressure of 1 X 1o- 6 Torr can be reached within 3
h from the start of evacuation from atmospheric pressure. At present the vacuum systemis operating satisfactorily. To improve ultimate pressure further, we are preparing metal gaskets
to replace the organic seals in near future.

132

10-10.

Heavy lon Source for the linac

M. Kase and Y. Miyazawa

The linac requires heavy ions with a charge to mass ratio of 1/27 < q/m < 1/4 from its ion
source. In order to produce such ions, a PIG source of a radially extracting type has been
designedl) and installed in the 500 kV terminal of the injector.
A cross sectional view of the ion source for gas-ion production is shown in Fig. 1. The anodeis made of water cooled copper. The beam exit slit in a replaceable molybdenum plate is 2 mm X
10 mm in size. The anode bore is 8 mm in diameter and the distance between the cathode and theanti -cathode is 100 mm.

The cathode, which is a tungsten rod with a diameter of 10 mm, isheated by the bombardment of electrons from a 0.8 mm ¢ tungsten filament. The filament currentof 36 A is supplied by a 19 kHz self-oscillator. The electron bombardment power required to burnthe arc discharge is about 600 W (800 V X 0.75 A). The anti-cathode is a molybdenum rod witha diameter of 12 mm.
The ion source is set in a 150 mm gap of magnetic poles. The magnetic field can be varied
up to 7.2 kG. Typical gas flow rate is o:s mf /min. The vacuum pressure around the ion source
during the operation is maintained less than 1.5 X 1o- 5 Torr by means of two turbo-molecular
pumps with pumping speeds of 450 and 3000 f/sec.
Electron supressor ( Mo )Fi Iament power Ieads
Insulator ( Al 20 3)

Filament ( W)
Fi Iament power
leads

Slit plate ( Mo)

Anode ( Cu )Anti - cathode ( Mo)

0

Fig. 1.

50mm

Cross sectional view of the PIG source for gas ions.

Figure 2 shows schematically the beam extraction arrangement.

The puller, which is mounted

on the extractor facing the anode slit, has a slit of 10 mm X 14 mm in size.
of the extractor to the ion source can be remotely adjusted.

The relative position

The extractor is biased at 0 - - 30 kV

against the anode which is at the potential of the injector terminal.

133

The extracted beam is bent through an angle of 120° in the magnetic field to give beam analysis
and horizontal focussing. The pole edge of magnet is rotated so that normal to the edge facemakes an angle of 30° with respect to the beam axis to obtain vertical focussing. 1 ) In addition,
the beam is focussed with an einzel lens.
Extractor
450 l/s

TMP

fi?I1J1
Yoke

Beam stopper
Insulator

Yoke
50cm

0

Fig. 2.

Plane view of beam extraction arrangement in the injector terminal.

--o,1'. ----=,....Qo-)<-::::-----------,
\

\
\

~

I

I

I
I

\
I

\

10- 1 1--------#------+---+-------+,-- - ----t
\

\

\
\

b
I
I

I
I

I
I
I

I

Cl)

>

I

I
I
I
I
I
I
I
I
I
I

---o--- Ar{~Kr- - o-- XeCharge stateFig. 3.
Charge state distributions of Ar,
Kr, and Xe ions obtained with the PIG
source. The arc conditions are 350 V X
1.6 A for Ar ions, 250 V X 4.5 A for Kr
ions, and 270 V X 2.9 A for Xe ions. The
maximum beam currents are 40 J.lA for
Ar 3 +, 5.6 J.1A for Kr 3 +, and 2.9 J.lA for Xe 5 +.

134

The ion beam passing through a beam slit of 10 mm X 10 mm in size are measured with abeam stopper. Figure 3 shows the typical data of the charge distributions given by the ion sourcewith a de arc operation. These are obtained for the magnetic field of 5.2 kG by scanning theextraction voltage.
In order to increase the yields of higher charge-state ions, it is necessary to improve the vacuum
around the ion source and employ a pulsed arc operation. For metal ions, the PIG source witha sputtering electrode in the anode wall is being built.

Reference
1)

Y. Miyazawa, M. Yanokura, M. Hemmi, F. Yoshida, M. Kase, and M. Odera: IPCR Cyclotron
Progr. Rep., 1l_, 151 (1979).

135

l 0-l l.

Power Supply for Heavy lon Source

M. Hemmi, T. Inoue, andY. Miyazawa

Figure 1 shows a schematic diagram of the power supply system of the linac ion source inthe high voltage housing of the injector. Power of 50 KVA required on the H. V. terminal issupplied by a generator driven by an insulation rod.
The upper tungsten cathode is heated by electron bombardment. Electrons are emitted froma tungsten filament of 0.8 mm in diameter. Frequency of heating current is 19 kHz and is
supplied by an oscillator. Coaxial cables of low inductance are chosen as current leads to reduce
the potential-drop between the filament and power supply. A current of 36 A (r.m.s.) is passed
through the filament to get sufficient electronic emission.
Electron bombardment power required to get the arc discharge is about 640 W. Since thecapacity of the power supply used at first was limited to about 1 A which was not sufficient forour purpose, the circuit was modified to increase the limit from 1.0 to 1.5 A in order to allow
enough margin in the current for the operation.
The arc current is continuously supplied by a rectifier having three operation modes. These
modes are specified by different inductances of the circuit. The voltage-current characteristics ofSchematic diagram of the power
Fig. 1.
supply (P.S) system of the ion source.

136

Q.)

00

2
0

>

0

5

10

Characteristics of theFig. 2.
arc power supply.

Arc cu rrent (A)the arc power supply is shown in Fig. 2.

For the present ion source we use the operation mode-l.
In this mode, the output resistance of the arc power supply is 25 n at the arc current above
8 A. It is planned to pulse the arc current to get highly charged ions in the future. Mode-2 or-3 will be used in this case.
The extraction potential is provided by a 30 kV DC power supply. The current capacity is
40 rnA. When heavier ions are extracted, however, we often observe the extraction current tobecome larger than 40 rnA. It is caused by increase of electron emission from the surface of theextractor bombarded by ions.
Half of the extraction voltage is applied to the center electrode of the einzel lens in order tofocus the divergent beam extracted from the ion source.
The magnetic field of 4 to 7.2 kG is required to produce and analyse all kinds of ions.
The coils of this magnet were made by copper-tapes with the edge cooling, called tape coil, toTable 1.

Ratings of the power supplies for the ion source.

Filament
Wave form
Voltage
Current
Regulation
Ripple (at full load)
Electrical isolationa)

See Fig. 2.

b)c)Current stability.

Electronbombardment

Arc

Sputtering
sourceExtraction

Magnet

HF

DC

DC

DC

DC

DC

10 V (rms)
70 A (rms)-1.3 kV
1.5 A-1.5 kV
10 A- 1.5 kV
1A

- 30kV
40mA
Voltage
<3V
GNDc)

80V
150 A
Current
1 X 10-4 b)
GNDc)

a)

5kVDC

<1%
5kVDC

<1%
GNDc)

<1%
GNDC)

GND means that one of the output terminals is connected to the chassis.

137

reduce the power consumption of the magnet. The maximum input to the primary of themagnet power supply is 20 kVA. This power consumption corresponds to one third of the total
power possible to use on the H.V. terminal. Power supplies on the H.V. terminal are controlled
at the control desk through photo-coupler devices. The devices are connected by a fiber lightguide 15 m long.
Table 1 summarizes the specifications of the power supplies.

138

10-12.

Multi-Wire Beam Emittance Monitor and BeamProfile Monitor

M. Saito, I. Yokoyama, M. Kase,
T. Kambara, and M. Odera

Two new beam diagnostic systems, one for profile measurement and the other for emittance measurement,
were fabricated and tested in the beam line of the linac. Each system is composed of multi-wire beam probes,
driving system for the probes, and electric circuits for control, data acquisition and data transfer which are linked
to the computer of the control system (HP-1 000).1)

The computer sends instructions to the systems, receives

measured data from them, and processes the obtained data numerically.
terminal of the computer.

The result is shown on a graphic CRT

Such on-line digital measurement system will be useful in future for closed-loop

operation of the linac.
Welded bellows

Pneumatic cylinder
Magneto- electri c valve

Fig. 1.

Wire

Beam profile monitor probe and pneumatic cylinder.

plare~
Slit

Pulse motor

A- An...;.-v/~
Ar
Wire plane

L
A

Slit plate

Fig. 2.

Beam emittance monitor probe and pulse motor.

139

1.
ProbesFigure 1 shows the profile monitor probe. It has a 12 X 12 wire net and each wire is connected to an
amplifier separately. The probe is driven by a pneumatic cylinder for fast insertion into and extraction from thebeam path. Beam profiles in x- and y- directions are taken simultaneously when it is inserted into the beam path.
The emittance monitor has two probes, one for x- direction and the othe r for y- direction. Figure 2 shows
the probe. The probe has a multi-wire beam current sensor and a 0.2 mm wide slit in fron t of it. A plane
containing each wire and the slit defines an angle to the beam axis. The probe moves across the beam stepwise
and at each position of step, it measures the beam currents emerging from the slit to different angles by themulti-wire sensor. At present, one step is 2 mm and each x- and y- sweep consists of 20 steps. The probes are
driven by pulse motors, because precise positioning of the probes is needed in the measurement.
2.
Control and data acquisition system(1) General
The control and data acquisition systems for the two types of monitors are almost the same except thedriving systems of the probes. Each system has a local unit near the beam line and a central unit in the control
room, connected together by a bit serial data line. The central unit is linked to the control computer via the
HP IB IEEE standard 488-1978 "Digital Interface for Programmable Instrumentation " . The local unit performs theactuation of the probes, measurement and digitization of the beam currents and transfer of the data to the central
unit, according to the instruction from the central unit. The central unit receives the data from the local unit,
stores them temporarily in its memory and sends them to the control computer. It also accepts instructions fromthe computer, translates and sends them to the local unit. Each unit has a microprocessor Intel 8080 to performthese functions. Figure 3 shows a block diagram of the system.
(2) Local unit
The local unit has a 12 bit ADC (analog-to-digital converter) section and a control circuit. The former is
enclosed in a shielding box separated from the latter to ensure good S/N ratio in measuring weak currents . It is
composed of 30 pre-amplifiers with high input impedance, paired with sample-hold circuits, a multiplexer and theADC. Variation of gain of the amplifiers is checked by supplying reference signals to each input through relays.
For the emittance monitor , a power supply for the pulse motors and an x- andy- channel switching circuit
are also included in the local unit. They are contained in a separated chassis from the other parts which aresensitive to electric noises .
(3) Example of emittance measurement
The central unit is in HLT (stand by) status when it is waiting for an instruction from the computer. The
Central unit
AMP
MPX
A- D
lF

Local unit

: Ampli fi er and sample-hold: Multiplexer: Analog-to-digital converter:Interface

P- S

TTY
KY
MEM

2

TW
DP

30

I

EPROM
6kB

Fig. 3.
system.

: :Q~~

L.:r@_J

EPROM
6kB

Cont rol computer

Block diagram of the monitor data acquisition

Fig. 4.

Flow chart of execution steps forthe case of the instruction " XO". Paths oftransfer of signals between central and local
units are indicated by dotted lines.

140

Cont rol comput er
HP 1000

Central unit

Fig. 5. Flow chart of execution steps for an
instruction to transfer the measured data to thecontrol computer.
unit accepts instructions related to the execution of measurements and the data transfer from the unit to thecomputer. There are 12 instructions for the measurements and 10 for the data transfer, each of which consistsof two ASCII characters. More details will be described elsewhere?) An example of emittance measurement isshown below: When the central unit receives the instruction "XO" which requires measurement of emittance in xdirection, it translates the instruction code and sends it to the local unit. The local unit reads the instruction andsends a ready status sign back to the central unit. The central unit reads it and sends to the local unit, information
to specify the probe position from where the measurement starts. The coordinate of the position has been manually
set on the panel of the central unit. Then the local unit makes a measurement , without beam current, to see thedeviation of the amplifier outputs from null, sends the data to the central unit and drives the probe to the positionof the first measurement. After the first measurement, the local unit moves the probe by a distance of 2 mm andsends the first data to the central unit if it is ready to accept them. After the data transfer process, the central unit
sends a non-busy sign to the local unit and waits for following data. The local unit becomes ready for the next
measurement when the probe arrives at the next position.
In this way the measurements are repeated and after the completion of the 20th measurement, the local unit
sends a sign of completion, draws the probe from the beam path back to the initial stand-by position and takes
the HLT status. The central unit stores the data from the local unit in its memory sequentially and when it
receives the final data, it lights a lamp indicating that it is ready for next instruction from the computer and goesback to the HLT status. Execution of the "XO" instruction is thus finished. Figure 4 shows the transaction
process between the local and the central unit.
Other instructions are executed in a similar manner. When any error in data transfer or delay of response of
more than 10 seconds is observed, execution of the instruction is interrupted, the probe goes back to the stand-by
position and error indication lights are lit on the panels of both units. The data transfer process is checked bycomparing the sums of corresponding bytes in memories of both units.
All the procedures of the measurement of beam profile are similar to that of emittance, except that themeasuring process is simpler and needs much shorter time.
(4) Data transfer to the control computer
When one of the instructions for data transfer is issued by the computer, the code is sent to the central unit
via the HP-IB. The central unit reads the instruction and transfer the contents of the memory to the computer.
Errors in the data transfer process is checked by the method mentioned above. The sum byte of the content of thememory of the central unit are sent to the computer after the completion of the transfer of the measured data.
The central unit then goes back to the HLT status again. Figure 5 shows the transaction process between thecentral unit and the computer.
The computer transforms the format of the data, checks the sum bytes and checks if the obtained data arewithin certain limits. If any error is found, a warning is given to the operator. The result of the numerical
processing of the obtained data is shown in the form of contour diagram or a graph on the screen of the graphic
CRT terminal (HP2648A).

141

10-1 3. A 100 em Scattering Chamber

I. Kohno, M. Yanokura, Y. Gono, and I. Takeshita

A scattering chamber has been designed for universal use in the experiments on nuclear
scatterings and reactions by the heavy-ion linac. A cross-sectional view of the scattering chamberis shown in Fig. 1.

The chamber is 100 em in inner diameter and 45 em in inner depth, andits main parts are made of stainless steel. The whole scattering chamber can be moved
horizontally and vertically for the initial installation. The side wall has 8 windows of 100 mm in
inner diameter. The movable parts of this scattering chamber are listed in Table 1. Shaftso( the turn table and the turn arms are of pipe structure. Each of them is supported
independently by a greaseless ball bearing which is fixed to a solid frame. With this system it

Fig. 1.
Cross sectional view of the scattering chamber.
1, Target holder, 2, Turn arm, 3, Turn arm, 4, Turntable, 5, Electric motor to move turn table, 6, Electricmotors to move turn arms, 7, Electric motor to movetarget holder.

142

Table 1
Turn table

Movable parts of the scattering chamber.

rotation in all angles with accuracy of setting±0.05°

Turn arm 2IIII±0.05°

Target holder 1

II

II

±0.5°

vertical motion 180 mm with accuracy of setting±0.5 mm

Adjustment: by remotely controlled electric motors
Indication of their position: by digital indicators and optical detectors

is possible to rotate them independently and to keep them free from the influence ofdistortion of the chamber.
free from oil.
chamber.

Special care is paid to make the scattering chamber vacuum to be

Teflon rings are used to reduce the gas flow from the rotation systems to theThis allows to apply a differential pumping of these two parts and to introduce therotation system without grease.

Two turbo-molecular pumps of pumping speeds 1500 f/sec

and 120 f/sec are prepared for the scattering chamber and the shaft parts of the rotation
systems , respectively.

143

10-14.

Design of an Electron Spectrometer

A. Yagishita and T. Nakamura

Auger, autoionization, and secondary electrons are ejected from an atom or molecule when a fast charged
particle is incident on it.

Much information on both atomic structures and dynamic excitation mechanisms

is obtainable by electron detection.

Thus, several works on electron-spectroscopic studies by high-energy

ion-atom collisions have been reported.

There is little data , however, on the studies by highly-stripped-ion impacts

at energies lower than 500 keV. Data on collisions between atoms and heavy ions , which have mass numbers
larger than 36, at energies higher than 100 MeV are also scarce. To investigate these fields of ion-atom collisions,
therefore, we started the construction of an electron spectrometer in the linac laboratory at the beginning of 1980.
Our design concerning the heart of the spectrometer, the energy-dispersing element, mostly has followed theidea developed by Kuyatt and Simpson l) for the use of an electrostatic energy filter of hemispherical shape. On
the other hand, in the design of electron-optical lenses to accelerate, decelerate , transport, and focus anelectron-beam from an interaction region to a detector , we have utilized electrostatic lenses of two or threeapertures.

The electron-optical properties of them such as focal lengths, principal plane positions, and sphericalaberration coefficients had been caluculated in Refs. 2 and 3.
Figure 1 shows the schematic drawing of the spectrometer with an electron gun.

Figure 2 shows thephotograph of it.

They are all placed in a vacuum chamber , in which the magnetic fields are reduced by double-layerJ.,t-metal shieldings.

Apertures defining the size of the electron-beam and electron-optical lenses were fabricatedfrom molybdenum.

Hemispherical electrodes, shielding cylinders of the lenses , and X-Y deflectors were madefrom stainless steel.
Some characteristics of the spectrometer are shortly described bellow. The radial distance of outgoing
electrons (x 2 ) from a mean orbit radius R 0 is given as a function of that for incoming electrons (xi), of electronenergy E , and of the incident angle a: of the electrons with respect to the mean orbit. This relation may beColl ision center

X- Y Deflector

Fig. 1.

A schematic drawing of the electron spectrometer.

144

Fig. 2.

A photograph of the electron spectrometer.

written as I)(1)
where E 0 is a mean energy and b.E = E - E 0 . Postulating that entrance and exit slits are of equal width w andthat the term a 2 of Eqn. (1) is neglected, the transmission of electrons through the hemispherical electrodes
would be given by a triangular figure as a function of E. FWHM (full width at half maximum) .6.E 112 of thetriangle is given by(2)

Addition of the a 2 term of Eqn. (1) has the effect of changing the shape of the transmission function.
reduce the tailing of the line shape, we have chosena :2 =

WI 4 R 0

To

(3)

•

Using Eqns. (1), (2), and (3) the base width b.Eb of the transmission function is given by(4)

The maximum deviation w m of the electron-beam from the mean orbital radius R 0 may be written as l)
Wm =

R0

b. E bE0+ {a 2+l/:2+ b.Eb ) :2 }
(Yi_
E
2R .

(S)

0

0

In order to transmit the whole divergent electron-beam, we have chosen a gap b.G = 20mm between the hemisphericalelectrodes.
When electrons having the energy E 0 in electron-volt travel on the circle of radius R 0 , the potential
difference V in volt between the electrodes in given by l)(6)

where R is the radius of the inner hemisphere, R of the outer hemisphere , and e the electron charge in
1

2

Coulomb.
The design parameters of the hemispherical deflector are easily calculated by Eqns. (2) - (6). They arelisted in Table 1 together with the predicted energy resolution for E 0 = 2, 20, and 50 e V.
Detailed description of the spectrometer , including the electrostatic lens system, voltage control unit, anddata acquisition system , will be presented with some experimental data in a literature.

145

Table 1.

Parameters of the hemispherical deflector.

Parameters

Calculated values

6-El/2 I Eo

0.01

6.Eb I Eo

0.025

a2

0.0707I Ro
wm I 1-,G

0.104

wm

0.260
2

20

50

(eV)
112
6.Eb . (eV)

0.02

0.20

0.50

0.05

0.50

1.25

V (Volt)

1.67

16.7

41.7

Eo

(eV)

6E

Mean radius R 0 = 50 mm .

E ntrance and exit virtual aperture w = 1.0 mm.

References

1)
2)

C. E. Kuyatt and J. A. Simpson: Rev. Sci. Inst., 38 , 103 (1967) .
F . H. Read: J. Phys. E, l_, 127 (1970).

3)

E. Harting and F. H. Read: Electrostatic Lenses, Elsevier Sci. Pub. Co ., Amsterdam (I 976).

146

10-15.

Electron Energy Analyzer

T. Shikata and A. Koyama

An electron spectrometer for the study of the energy and the angular distribution of electronsejected from metal surface by fast ion impact is now under construction.
In order to measure the electrons ejected in various directions from 0 to 180° with respect
to the incident ion beam direction, slots must be provided in the electrodes of the analyzer toallow the ion beam to pass through. Such an arrangement , however, cause the lowering of the
To avoide such lowering, we used energy filters with a slottedparallel plate type analyzer, employing the principle of the energy analyzer used in the "DUPONT

resolution of the analyzer.

650 ELECTRON SPECTROMETER" .
A schematic drawing of the analyzer is shown in Fig. 1. The trajectory of the electrons
is shown by dotted line. The electron beam is first retarded to match the energy of theparallel plate type analyzer which plays a role of a narrow band-pass filter. The deflected
electrons pass through a quadrupole lens which aligns the beam, and enter into the low-passfilter. The reflected low energy electrons again pass through the quadrupole lens and enter
into the high-pass filter via a deflector.

The transmitted high energy part of the electrons isElectron I ens 1~-+-....,........_-""L-- Target!on beam
cage'l- --- Detector
Electron lens 2'----~ High - pass filt er
Deflector
I

-

I
I

I
I

I

I

I

I

lens

I:

-4 -r -

t-' -~- ~ - -,--1----_ Low- pass filter

I
IlFig. 1.

Schematic drawing of the analyzer.

147

accelerated and is collected in the detector. If we set the band width formed by both filters
narrow, the improvement of the resolution is attained . Energy spectra of electrons will beobtained by scanning the retardation potential applied on the electron lens 1.
The instrument can be rotated around the axis A-A passing through the beam spot on thesurface of the target.
Magnetic shielding is carried out using double mu-metal cages.
Data acquisition system is also in preparation.

148

10-16.

Design of an Apparatus for RILAC-Beam Irradiation of
Biological Samples

F. Yatagai and S. Kitayama

An apparatus was designed to study various effects of high-LET radiations on biologicalmaterials. One example to be studied is the biological effects observed with the increase of highenergy secondary electrons (8-rays) accompanied by an increase of atomic number of incident
heavy particles.

The method is to irradiate samples by the elastically scattered beam at a certain

angle with respect to the beam axis (Fig. 1). This method has already been applied for theirradiation at the IPCR cyclotron. The biological sample mounted on a holder faces the vacuum
window and can be rotated for the uniform irradiation, because the relative intensity of scattered
beam decreases with increasing scattering angle.
An attempt was made to improve the irradiation system used at the IPCR cyclotron.

The

most important improvement is to place two independent slit boxes between the bending magnet
and the scattering foil for better beam-collimation (Fig. 1). Moreover, the center of the plate,which contains four sample-holders arranged in a circle, can be adjusted to coincide with thebeam axis for the irradiation of each sample at the same dose rate.

It is expected from many points of view that this irradiation system will provide an accurate
dosimetry and a uniform irradiation.
B

Fig. 1.

Scheme of the apparatus

for RILAC- beam irradiation of biologicalcSamples. (1) Bending magnet, (2) Beam
shutter, (3) Turbo molecular pump, (4)Slit box, (5) Beam stopper, (6) Scatteringfoil, (7) Solid state detector, (8) Vacuum
window, (9) Sample holder, ( 10) Faraday
cup, (11) Thermostat.

Reference
1)

F. Yatagai and A. Matsuyama: IPCR Cyclotron Progr. Rep., _!_1, 118 (1979).

149

10-17.

Beam-Foil Spectroscopy

K. Ando and K. Mori

Radiative transition probability is one of the most important atomic parameters. A uniqueexperim·ental method of deriving the transition probability is to measure the radiative mean livesof the upper excited electronic states of the emission multiplets produced in the "beam-foil"
source.

Recent interest on beam-foil spectroscopy is in the study of highly ionized heavy ions.

The foil excitation technique can be used efficiently on heavy ion beams accelerated by linear
accelerators. In case of the IPCR heavy ion linear accelerator, multiply-ionized heavy ions are
expected for use on beam-foil spectroscopy. On the other hand, atomic wavefunctions can
now be calculated with sufficient accuracy to enable theoretical computations of radiativetransition probabilities to be made. The theoretical estimates are based mainly on either
self-consistent field (SCF) calculations, including configuration interaction (Cl) if necessary, or
Coulomb approximation. Computational techniques are recently in so highly advanced stage
that the complicated calculations for SCF plus CI are practicable.

Therefore, the sophisticatedcalculations, such as multi-configuration relativistic Hartree-Fock (MCRHF) SCF, including
Lamb shift, give us the ab initio theoretical oscillator strengths and transition probabilities forheavy ions. Several convenient computational codes are now available.!) Therefore, it isimportant to obtain accurate experimental data of transition probabilities in order to comparewith the theoretical ones deduced from the advanced wavefunctions.
Preparation for beam-foil experiments on highly ionized ions from the heavy ion linear
accelerator at IPCR has been almost completed. The experiment of beam-foil spectroscopy is
Vacuum pump~-ll----~11--jj_

k===n=':~~~~~::=:~:===n===r1

Fig. 1.

heavy
Ion

Schematic drawing of beam foil experiment.

150

to be performed as illustrated in a schematic drawing of Fig. 1. The accelerated ion beams
transmit through a carbon foil, being further stripped and excited. Spectral emission of theexcited ion decays along the travelling path. Decay time of the emission, thus life time of theexcited state, can be measured through the displacement distance from the foil. In the present
case, the relative distance between the foil and the monochromator entrance slit, which observes
the emitting ion, is changed by moving the foil continuously upstream from the slit. The
maximum movable distance is 500 mm, and the accuracy of determination of the foil position iswithin ±25 Jlm. The target chamber accomodating the above mechanism is evacuated by aturbomolecular pump of 500 !!/sec. Spectra from the emitting ions are observed by a 2-m
NIKON McPHERSON (Model 24 7) grazing incidence monochromator. Highly ionized high Z
ions have so large transition probabilities for the resonance transition that the lifetimes of theresonance upper states are too short to be observable by the usual experimental setup. We
attempted to redesign the entrance slit assembly of the monochromator in order to observe theion beam as close as possible. Thus, the distance between the entrance slit and the ion beam
become about 5 mm, which corresponds to the space resolution along the beam of 0.06 mm,enabling the lifetime even smaller than 0.1 nsec to be measured.

Reference
1)

For example , G.E. Bromage: Report AL-R-3 Appleton Laboratory, England (1978).

151

10-18.

Multichannel

Detection m Normal-Incidence Vacuum
Ultraviolet Region

M. Hara and K. Mori

Recently a microchannel plate (MCP) is used as a position sensitive detector array for one
or two dimensional iJI?age dissection.n

A multichannel detector system with microchannel plates

has been constructed and used for polychromatic observation of vuv emission spectra of laboratory
plasmas by single photon counting method. As is shown in Fig. 1, a set of cascaded microchannel
plates is used as one dimensional detector array. Photoelectrons produced by an incident
photon at the surface of MCP are multiplied, and the multiplied pulse charges are collected bymultiwire anode. Each wire is connected with the neighbors by resistances (51 0 Q) and bothend wires are fed to charge sensitive pre-amplifiers. The charges arriving at the particular wireof the collector are- divided by the resistance network into two charges qa and qb which are
inversely proportional to the resistances. One can determine the position of the incident photon
by the simple calculation qa/(qa + qb) and the data are stored in PHA. We get better spatial
resolution than the interval between wires by this charge division method in which the centerof gravity of charges is calculated. 2) The MCP used in this work is that of Hamamatsu TV
Fll58-13 type whose channel diameter and channel pitch are 20.0 and 24.5 }lm, respectively.

L-x

~
qa

X

qa +qb

L

~

==

X

qa
==
qa +qb

P A
M A

X

L

O RTEC 14 2A
571

SUM
DIVIDER
PHA

11

4 33 A464

400 c hUSC

Fig. 1.

Schematic diagram of position

analyzer electronics.
This was operated at 0.94 kV for the first MCP and 1.17 kV for the second one to reduce noise
pulses keeping high gain. Multiwire anode is made of 60 - 75 parallel 40 }lm</> stainless steel
wires fixed to the epoxy-glass frame with epoxy resin using a winding machine which consists ofrevolving cylinder and feeding screw.

The anode is 10 mm in length and 9 mm in width with150 }lm interval or 12 - -15 mm in width with 200 Jlm interval. Linearity and resolution ofthis system were checked by feeding the noise pulses of ordinary secondary electron multiplier tube
to each wire.

Spatial resolutions of 70 - 80 Jlm (200 Jlm interval anode) and 50 - 60 }lm(150 Jlm interval anode) were obtained.
For this application, this detector system is set at the focal plane of normal incidence

spectrometer, as is shown in Fig. 2.

This spectrometer has a grating of 1200 f/mm and a152

reciprocal dispersion of 5.5 A/mm which is almost independent of wavelength. Each channel of
MCP has such a long dead time (some tens of msec) that a light source is set at a distance 30 em
apart from the entrance slit of the spectrometer in order to decrease the flux density at thesurface of MCP. As the light source we used an ordinary glow discharge tube made of quartz
capillary. Pressure in the light source can be varied from 0.01 to 0.2 Torr. Voltage and currentof the discharge are 500 - 600 V (depending on gases and pressure) and 200 rnA (stabilized),
respectively. Neon doublet at 735.9 A and 743.7 A, argon resonance doublet at 1048.2 A and
1066.7 A, and hydrogen Lyman~ at 1015.7 A were detected with good S/N ratio.

The

spectra obtaind showed the FWHM of 0.5 A (wavelength) or 90 Jlffi (spatial resolution) in case of
200 Jlffi interval anode and 0.33 A or 60 Jlffi in case of 150 Jlm interval anode.

We get better

wavelength resolution and S/N ratio by measuring vuv emission at higher spectral orders, because
the dispersion becomes larger and MCP itself has little sensitivity in visible region. We measured
the profile of the Hel 584.3 A resonance line at the 5th order by varying the source pressure.
Typical spectra obtained with 150 Jlffi interval anode are illustrated in Fig. 3. The lower

IN-PLANE EAGLE MOUNTINGDISPERSIONENTRANCE SLIT

5.5

~ /mm

1200 1/ mm

CAPILLARYDISCHARGE TUBE
5mmct>x 100mm

MCP
ROWLAND CIRCLE
1500 mmq,

Fig. 2.

Schematic views of normal incidence spectrometer.

Hel 584.334 LINE
measured at the 5th order

P1 = 0.1 Torr
P 2 = 0. 1 5 Torr

20007 sec160(/') 80
~

z
::J
0

u

04-------+----*--~-----+­

P1 = 0.022 Torr160

P2 =0.033Torr
1 81 9 0 sec

80

o+-------~-----;------~-

584
WAVE LENGTH <f~)0.0081. Z.tch

585

Typical spectra of Hel 584.334 A
Fig. 3.
line obtained with this detector system.

153

spectrum measured at lower pressure showed FWHM of 0.066 A (wave-length) or 60 J.Lm. On
the other hand, the upper spectrum clearly shows spectral broadening and dip. The dip of thisspectrum is due to the resonance absorption through the path between the light source slit andthe entrance slit. Taking account of the plasma parameters of this glow discharge, natural
broadening and pressure broadening (Stark and resonance broadening) can be neglected comparedwith Doppler broadening. Even if the resonance absorption and detector width are taken into
account, the broadening of the upper spectrum cannot be explained without recognizing that theneutral helium at the excited states has Doppler temperature of several electron volts.

References
1)
2)

J. G. Timothy and R. L. Bybee: Appl. Opt., 11, 1632 (1975); G. Knapp: Rev. Sci.
Instrum., 49 , 982 (1978).
R. Gott, W. Parkes, and K. A. Pounds: IEEE Trans. Nucl. Sci., NS-17, 367 (1970).

154

10-19.

Spherical Target Chamber for Heavy-lon Implantation

M. Iwaki and F. Ambe

A versatile target chamber for implantation and other irradiation experiments has been
designed, constructed and installed at the end of beam line C of the heavy-ion linac, as shownin Fig. 1.
The main part of the chamber is a spherical SUS304 vessel with an inner diameter of 315 mm
and is equipped with ports for incident beam, target drive mechanism, target setting, vacuum
pump, and so on.
The beam from the linac is introduced into the chamber through two pairs of slit plates,
which can be independently moved in the horizontal and vertical directions by remote control.
Each plate is connected to a BNC standard connector for monitoring the ion beam current.
Between the slits and the chamber is a beam shutter which can be also operated from the controlroom.
The target holder can be moved in the vertical direction (±20 mm max.) and rotated aroundthe vertical axis ( ±45° max.) by servo and pulse motor drives respectively. During irradiation
the movements can be repeated at a speed selectable within a definite range. Combination of
the two kinds of movements can be also selected.

The drive mechanism is used to position the3( 1) Door with window for target setting(2) Leak valve(3) Spare flange( 4) Gauge port
(5) Flange for target-drive mechanism(6) Target-drive mechanism(7) Viewing window(8) Spare flange(9) Viewing window( 10) Flange for incident beam(ll)Slit(I 2) Bellows( 13) Servomotor for vertical drive oftarget( 14) Pulse motor for rotation of target
Fig. 1.

Sketches of the chamber.

155

target, to disperse the heat generated in the target by irradiation, or to ensure uniformity of theion beam across the substrate area.

The target holder can be cooled with water or liquid

11itrogen, which is introduced into the holder through a pair of mini-bellows.

The holder isinsulated from the chamber in order to indicate the beam current on the remote panel.
The evacuating system consists of a 250 £/s turbo-molecular pump and a 244 £/min rotarypump.

All the vacuum valves are driven by compressed air.

from accidents due to a mistake in operation.

The whole system is protected

Throughout the system Viton 0-rings and metal

sheets are used as seals.
The chamber is to be utilized in heavy-ion implantation of materials such as steel andsemiconductors and also in a wide variety of irradiation experiments.

156

10-20.

On-line Data Processing System at RILAC

H. Kumagai and T. WadaPERKIN ELMER model 3220 super mini-computer system has been introduced for on-line
data taking and data processing.
In March 1980, the initial system was installed in a counting room at RILAC.

It includes

P-E 3220 central pro cesser with bootstrap loader, memory error logger, floating point pro cesser
and 512k byte ECC MOS memory, a 9-track magnetic tape unit of 1600 BPI, an 80M byte
cartridge disk, two cassette magnetic tape units, two CRT terminals, a DEC writer, a line printer,a digital plotter, and a CAMAC crate.
Boot strap Ioader
Memory error logger
Floating point processor
Character display

DEC Writer IILine printerModel 5130

Digital plotter( CALCOMP)
DP /--jModel 1012
, - - - - - - - --,1

1

1

r---+--+-~, ----lList mode I I 16 :interface H:(custom) i : A DC:~----Jt_ _________ j

rS~Paramete-rl

I multi-scaler I: interfaceIr---+--+---id ~~_!_o~_)---J

Character display
model 550

Fig. 1.

Model 432

Configuration of data processing system.

The interfaces

enclosed by dashed lines will be installed in April of 1981.

The

abbreviations are, ECC for error check and correction, DRAM fordynamic random access memory and EDMA for extended direct
memory access unit.

157

Additional 256k byte memory, an 80M byte cartridge disk , a graphic display interface,a 19 inch CRT, a PHA mode interface and eight NIM-ADCs were installed in September 1980.
The present configuration of the system is shown in Fig. 1.
The specification of P-E 3220 computer are as follows:
Processor
General registers

8 sets of 16 , 32 bit g.r.

Floating point
registers

8 sets of 32 bit f.p.r.
8 sets of 64 bit f.p.r.

User instruction

200 ( 48 floating point)

Execution time (Reg. to Reg.)

Addressing
Arithmetic
Main Memory
Type
Word Length
Size
Access time

Add
Multiply
Add (f.p. 64 bit)
Multiply (f.p. 64 bit)

0.45 JJ.S
7.85 JJ.S
1.25 JJ.S
1.85 JJ.S

Divide (f.p. 64 bit)
Direct to 4M byte
Relative to ± 16k byte
2's complement

7.05 JJ.S

16k byte DRAM (TMS 4116-15)
32 bit + ECC (7 bit)
Up to 4M byte
500ns
340ns effective with cache

1/0

DevicesPriority
EDMA
Operating System1023
4 interrupt levels
7 ports , 8M byte/sec
OS/32

Languages
CAL (common assembly language)
CAL MACROFORTRAN-7
COBOL
BASIC-2
The abbreviations are, ECC for error check and correction , DRAM for dynamic random accessmemory and EDMA for extended direct memory access unit.
The specifications of custom made interface are as follows:
For the increment (PHA) mode interface:
(1)

(2)

maximum 8 ADC's with 13 bits are connected ;the data from ADC's are stored in FILO (first in last out) memory of 64 words ;

158

(3)

the contents of main memory corresponding to the data of FIFO are read, modified
and stored through DMA channel ;( 4) a X-tal oscillator (1 MHz) is prepared to measure true time or live time of each ADC;
For graphic display interface:
( 1)
(2)
(3)
(4)

a buffer memory of 60k bytes is included ;16 sets of register are prepared to store the DMA commands ;the display modes are X-Y and T-Y;
the change of Y scale including a logarithmic scale is performed by hardware ;(5)

maximum 4 spectra can be overlaped and shifted independently in Y direction;

(6)
(7)

the display areas in the main memory are selected by 37 toggle switches;the position of each marker is determined by thumb switches or a light pen.

The CAMAC system is prepared for the control of other experimental devices.

159

10-21.

Beam Sharing System between linac and
Separated-Sector Cyclotron

M. Sasagase

The possibility of placing a beam sharing system between the linac and the separated-sector
cyclotron (SSe) was examined. This beam sharing system should be set up between the 6thtank and the switching magnet of the linac.

Within the variety and the energy regions of ionsaccelerated by the linac, the beam sharing should be possible and furthermore the beamtransport system must be achromatic especially for the injection to the SSe. The analysis of thebeam transport optics showed that such a beam sharing system satisfying these requirements is
feasible.
The calculation of the beam transport optics was carried out within the first-order formulation
using the program TRANSPORT 1 ) in the cases of 238 U 10 + (200 MeV) and 20 Ne4 + (80 MeV)
beams. Hereafter, the incident beam is assumed to be u 10 + ions.
The arrangement of the beam sharing system is shown in Fig. 1. U 10 + ions accelerated by
the linac are partially stripped of their electrons by a stripper foil at S0 . Unstripped u 10 + ions
are guided to the switching magnet (SW) through bending magnets BM 1, BM2, and BM3.
ions are selected by a slit at S2 to be guided to the sse.
in Table 1.

xwo
v7'

U40 +

Parameters of each elements are listed

TANK

8M1

8M2

8M3 5,

SW

BM5

..

I - -1- - - - -

~
BM6

BM7

502

D- 0 - -0 -D-1 J_

501,, : : , : :, , , , , ,,, m , n

' n

BM6

5

'----'

1m'"'"""=~~(b) plane drawing(a) side viewFig. 1.

501

[IJ-D

Arrangement of the beam sharing system.

The feature of the initial beam at S0 is assumed as follows: ( 1) the half-width of theenvelope is 5 mm and the angular divergence is 5 mrad both horizontally and vertically, and (2)the half-width of the momentum spread is 0.075 %.
possible.

Achromatic transport from S0 to S 3 isThe beam envelopes are exhibited in Fig. 2.

The trajectories of U40 + ions are well

separated from those of U 39 + ions, as shown in Fig. 3. In the calculation of optics, care wastaken so that the half-width of the beam envelope does not exceed 2 em. However, for thetransport of u 10 + ions to the SW, the half-width of the beam envelope somewhat exceeds thislimitation at the exit of the SW. A more parallel incident beam, for example, a beam with thehalf-width of the envelope of 8 mm and its divergence of 3 mrad, is desirable to avoid this difficulty.

160

Characteristics of transport elements.

Table 1.
Bending magnets
Element

Angle ofbend (deg)Radius (em)Magnetic
field (kG)

{3~)

{3~)

BMl

45 (11.5c) )60 (240C) )13.09d)8.2

0.3(0C) )

BM2

23c)

240C)

13.09d)

14.8

14.8

BM3

11.5 c)240C)

13.09d)

0

8.2

BM4

45

60

13.09d)

9.8

0

BMS

90

60

13.09d)

10.6

29.0

BM6

45

60

13.09d)

0

0

BM7

45

60

13.09d)

31.4

-11.5

Singlet quadrupole magnets
Element

Length (em)Radius (em)

SQ1

20

3.81

SQ2

20

3.81

a) angle of pole-face rotation at the entrancec) in the case of 238 lJ 10 + (200 MeV)e) in the case of 238 U4 0+ (200 MeV)

238

3 1:

40

... 8d"'db) angle of pole-face rotation at the exitd) in the case of 238 U4 o(to )+ (200 MeV)

DP = 0.075 .,,X=5.0 MM DX=5.0MR Y=5.0MM DY=5.0MR

U • E = 200 MeVBEAM ENVELOPE~

u'i

Magnetic
field (kG)

1:

~

d

.,.;

"'
d

'i
,__

,_

~

w
z

LL

~

(i'

'1

:l:

0

w

§ ~ ~ 'zJ.

"-

"-

~

--:

~

10

2

2

...; 0

0

0

U'l

2

2
co
ci

lJ")

(j)

ci

,..;

"'z

1.9
<{

;.

w

z
~

"-

~

"-

~

~

;:

<.D

2

~i

~

N

0

U'l

(IJ

(IJ

DP = 0.075 .,,E = 200 MeV

U +X=8.0 MM DX=3.0MR
y = 8.0 MM DY =3.0 MR

BEAM ENVELOPEu: l ~~

lD

lD

238

~

~

2

lD

~ ~.

"-

"-

~

~

2
--:

2

2

r--

~

2

lJ")
lJ")

0

lJ")

0

,..;

,...;

...:

l'i

....:

-

ci

1LL.

a:

0

1-

I-

LL.

~

~

co

a:0

1-

LL

N
~

co

0:
0

M

~

co

LL.

1-

0

w

a:

x

Beam envelopes in theFig. 2.
vertical (x) plane (solid lines)
and the horizontal (y) plane(dashed lines).

161

zJau

02
. 0

lf)

d

E=200 MeV

2:

2:

2:

lf)

['..
(J)

~
(J)

c)

2:

....;

d

2:
~
(J)

cv5

-.i
cv5

....;
...:
c)
I

....;
I

r-

7~

(9

.a:

~0
I

r-

w

z

rlL

~

<t

2:

i

CD

Fig. 3.

Single rays for 238 U39 + and

w

z

r-

<t

a:
0

lL

<.')

2:

~

~

tlL

a:0
r})

CD

238 U40 + ions at the

charge selection part.

When Ne 4 + ions are used as the incident beam, Ne 4+ and Ne 10 + ions are guided to the SW
and the SSC, respectively. The central trajectory of Ne 4 + ions differs from that of u 10 +ions.

So the magnetic field of the BM2 must be adjusted to return the trajectory to the initial
beam axis.

Reference
1)

K. L. Brown, F. Rothacker, D. C. Carey, and Ch. Iselin: SLAC-91 (1974).

162

11. SEPARATED-SECTOR CYCLOTRON PROJECT

11-1.

Status of the Separated -Sector Cyclotron m

IPCR (Riken)

H. Kamitsubo
Construction of an accelerator complex composed of a separated-sector cyclotron (SSC) and
two injectors was proposed in 1972 to extend the studies in various research fields by energetic
ion beams in IPCR.

The first part of this proposal was accepted in 1974 and the variable-

frequency heavy-ion linac (Rilac) was installed in 1980. The second part of the proposal has
been funded this year. The final design works are now in progress.
Construction of the big accelerator complex is a major part of the IPCR Accelerator
Science Project which aims to develop the accelerator-assisted studies in the various research
fields such as nuclear and atomic physics, solid state physics, nuclear and radiation chemistry andradiation biology. Accordingly the SSC as well as the Rilac should be able to accelerate not only
light ions but also heavy ions in the energy range as wide as possible. The SSC is also required
to provide a beam of good quality and of enough intensity.
The design goal of the SSC was thus fixed to achieve the maximum beam energies of 130
MeV/u for fully stripped light heavy-ions and 14 MeV/u for very heavy ions such as uranium.
Those for other kinds of ions will lie in the range between these two values. We expect that
protons will be accelerated up to 200 MeV. Energy variability should be realized down to 10
MeV /u for most kinds of ions. High resolution beams of protons, deuterons and ex particles will
be required for the study of nuclear physics and therefore the beam quality has to be as highas possible.
Table 1

Examples of some operating parameters at maximum energies in the
proposed accelerator complex.

sse

LINAC
Beam

Charge m/qi
(ql)

Accelerating RF

Energy per

freq. voltage(MHz) (MV)nucleonCharge(MeV/u)

(q:z)

m/q2

Bmax
Binj
(Wb/m 2 ) (Wb/m 2 )Orbit Acceleratinghnumberfreq.
RF freq.

Energy per

(MHz)

(MHz)

(MeV/u)nucleon

40Ar

8+

5

44

20

3.8

15+

2.7

1.45

1.55

4.8

43.3

9

66.6

84Kr

9+

9

33

20

2.2

24+

3.5

1.45

1.5

3.67

33

9

36.8

132xe

9+

15

26

20

1.36

30+

4.4

1.43

1.46

2.88

26

9

22.3

238u

10+

24

20.4

20.4

0.84

37+

6.4

1.55

1.57

2.14

19.4

9

12.1

5.9

1.52

1.54

2.27

20.4

9

13.6

0.838

0.994

7.37

44.2(29.5)

6(4)

184

1.26

1.49

7.37

44.2(29.5)

6(4)

184

39.1 (26.0)

6(4)

134.6

40+
Cyclotron (Rext = 0.893 m)
Energy per
Bext
nucleon(Wb/m 2 ) (MeV/u)

Orbit
Charge freq .
(MHz)

freq.

p

1+

7.37

22.1

0.485

9

1+

3He

2+

7.37

22.1

0.727

9

2+

Beam

12c

4+

6.51

RF

(MHz)

19.6

1.28

7

6+

1.5
2

1.48

1.67

6.5

163

The accelerator complex consists of the SSC and two injectors, one being the Rilac and theother a cyclotron of k = 90.

Examples of operating parameters at the maximum energies forseveral kinds of ions are listed in Table 1.

The beam from the Rilac will be injected into the SSC

after it passes through a charge stripping foil.

Matching condition of the resonance structure of

the beam between the Rilac and the SSC gives a limitation on the RF system of the SSC: widthof the accelerating electrode (delta) at the injection radius should be equal to the length of thelast drift tube of the Rilac and also the RF frequency should be exactly the same for both
accelerators.
The Rilac accelerates ions in the fundamental mode, that is, with a harmonic number of 1
over the frequency range of 17 - 45 MHz. The harmonic number, h, of the SSC was determined
to be 9 from the matching condition with the Rilac and the maximum field strength of thesector magnets. The injection radius is 0.89 m in this case. The above value of h is different
from that reported previously.

This is because we decided to reduce the maximum field strengthof the sectors from energy saving point of view.

The maximum value of Binj was reduced from
1. 7 to 1.5 5 T and the injection radius was increased from 0. 79 to 0.89 m.
The matching condition between the SSC and the injector cyclotron has to be taken into

account, too.

The simplest combination of the parameters is that the extraction radius of theinjector is equal to the mean injection radius of the sse and the ratio of the harmonic numbers
is an integer.

Since the injection cyclotron will be operated in the orbit frequency range of 2. 7

- 7.5 MHz, h = 3 and 6 are favourable values for the injector and the SSC, respectively.
The beam from the Rilac should be transported by about 60 m to the SSC.

The beamtransport system is designed to bring the beams without any loss and also to match the beam
quality to the acceptance of the SSC.

Two RF bunchers will be installed to get the phasefocus at the injection point of the sse.
In the early stage of the design work, a horizontal injection was extensively studied.

Itbecame clear that stray field of the sector magnets is not so small that the injection orbit varies
considerably depending on the ions and their energies.

In that case a quadrupole doublet andsteering magnets of large apperture will be necessary to inject all kinds of ions correctly.

New

methods of the injection were, therefore, looked for and finally a canted injection was adopted.
The SSC has four sectors of 50° with straight edges.

The sector magnet and 30 trim coils

yield the required isochronous field of 1.67 T at maximum.

The focusing properties have been

extensively calculated with computer codes developed by N. Nakanishi and by A. Goto,
independently, by using measured field distribution for a pair of a quarter scale model magnets.
Ions are accelerated by 20° delta-shaped electrodes located at the opposite valley spaces
between the sectors.

The RF frequency range of the RF system is chosen to be 17 - 45 MHz
as mentioned above. RF electric field distribution and quality factors were measured for a halfscale model cavity. The effective accelerating voltage for the cyclotron injected beam will be
2/3 of that for the Rilac injected beam.
The beams from the injectors are brought slantingly into the SSC through the valley andbent by 45° onto the median plane in the central region. Then they are inflected by 100° witha bending magnet and enter the magnetic inflection channel between two pole tips of the first
sector magnet.

The second magnetic channel and an electrostatic inflector bring the beams onto
the first equilibrium orbit.
Detailed design studies of the vacuum chamber, RF resonators and other components are
now in progress.

Recently the sector magnets were ordered to Sumitomo Heavy Industry Co.

164

11-2.

Design of the Sector Magnet for the SSC

S. Motonaga, H. Takebe, T. Wada,
Y. Obana, J. Fujita, and Y. Ikegami

The separated-sector cyclotron (SSC) projected at IPCR has been designed as a post accelerator for thevariable-frequency heavy-ion linac and the conventional AVF cyclotron. The main characteristics of this SSC
are described in this report by H. Kamitsubo. A number of possible technical realizations were considered, one ofthese being operation with the harmonic number of 9 in place of 8 in order to reduced the maximum field of
the magnet and to obtain wide space in the central region of the SSC. The maximum magnetic field was reduced
from 17.5 to 15.5 kG and the injection radius was increased from 79 to 89 em . The geometrical size and the
major design parameters of the sector magnet had been fixed. Remaining problem for the final design of themagnet is mechanical design of the trim coil system and the design of the vacuum chamber connecting the magnet
chamber and RF resonating chamber in narrow central space of the SSC.
GeneralThe profiles of the magnetic field should provide the isochronism, focusing and orbital stability for the beamin a wide range of energy and particles. In order to get desired field profile in the range of 7 to 15 .5 kG,
measurements of the magnetic field have been carried out using a 1/4 scale model of the sector magnet. The final
parameters of the sector magnets were determined from the results of the analysis of the magnetic properties andcomputation of beam dynamics based on the above measurements. Table 1 lists the design parameters of thesector magnets. The main magnet system of the SSC consists of four sector magnets with sector angle of 50°, gap
distaoce of 8 em and maximum magnetic field of 15.5 kG. The maximum magnetomotive force was estimatedto be 1.35 X 10 5 ampere turns for the maximum field of 15.5 kG. The maximum power consumption of themain coils is estimated to be 520 kW. Each sector magnet is about 5.7 m long and its weight is 540 tons. The
shape and geometrical size of the sector magnet is shown in Fig. 1.
Poles and yokes
The pole tip contour and pole edge profiles are shown in Fig. 2. The pole edge profile except the innerpart is approximated by a B-constant profile so that the effective angle of the sector magnet does not change in therange of magnetic field to be used. This was confirmed by the analysis of the magnetic field computed by TRIM
Table 1.

Design parameters of SSC magnets.

Number of Sector Magnet
Sector angle
Gap width
Injection mean radius
Extraction mean radius
Height of magnet
Overall diameter
Total weight

4
50°
8cm
89.3 em
356 em5.63m
12.8 m2160 ton(540 ton/one sector magnet)

Maximum magnetic field (excitation)
Maximum ampere turns
Maximum current
Current stability
Maximum power
Number of trim coils
Maximum current
Total trim coil power

15.5 kG
1.35 X 10 5 A.T1160 A
0.002 %
520 kW
30 pairs X 4
500 A
280 kW

I

I

lD

00
N

11~I=

l JI

lD

lD
lD
lD

-r

I

Fig. 1.

II~- - r-- o
(Y)
<.0

1

lD

8

I

N

I

I

Geometrical lay-out of thesector magnet.

165

code and the measured field of the model magnet. The effective angle obtained from model measurements agrees
with the designed value of 50° within 1.0°. However, this profile can not be used at inner edges of the polepieces as shown in Fig. 2, because the usable range of the magnetic field in the radial direction will be reduced by
the B-constant profile. Radial dimension along the central line of the pole tip is 3317mm. In the radial direction
the pole tips extend 3.5 gaps toward the center from the first equilibrium orbit and 3.0 gaps outward beyond theextraction equilibrium orbit.

The gap spacers and the components necessary for the injection and extraction

will be inserted in these extended areas.
A-A~.-~~~~~~=­
N't--~~::_

Fig. 2.

Pole tip contour of thesector magnet.

( 606 2)
r-1

The upper and lower yokes will be divided into four or five slabes for convenience of the construction andtransportation.

Cross-sectional area of each Yoke is equal to that of the pole base.

The maximum field andthe field profile of the sector magnet strongly depend on the iron material. Very homogeneously forged steel
with carbon content of 0.02 - 0.01% were specified for the pole and rolled steel of 0.08 - 0.1 % carbon content
for the yoke of each magnet.

Two poles of each sector magnet should be prepared from a single ingot.

Table 2shows specification of the steel. The specified mechanical tolerances of the alignment for the construction are
0.1 mm and 0.05 mm for coaxial and parallel alignment, respectively, of the poles without magnetic field.
Table 2.

Specified chemical composition of the low
carbon steel (weight percent).

Pole
Yoke

c

Si

Mn

p

s

Cr

Ni

Cu

Al

Mo

N

0.02
0.08

0.07
0.25

0.2
0.35

0.05

0.017

0.08
0.08

0.10
0.10

0.11
0.11

0.03
0.04

0.04
0.05

0.006
0.007

0.013

0.012

Main coils
The design of the main coils has been almost completed. Final design, however, may be changed slightly
according to the result of the design of the vacuum chamber. They will be formed in size of 3.5 em in thickness
and 55 em in height to provide enough space for the RF-cavities which will be installed in the narrow space between
two sector magnets. The main coils of each sector magnet will be connected in series and excited with maximum
current of 1160 A. Maximum current density of copper conductor is 4.5 A/mm 2 .
Deformations
The deformation of the magnet structure as a result of various forces acting on it was computed by FEM-2
code developed by M. Hara. The computed deformation is shown in Fig. 3 and Fig. 4. The maximum
displacement relative to the foundation is 0.11 mm vertically and 0.05 mm horizontally. The maximum value
for the spacer compression is 0.08 mm for the front one and is 0.05 mm for the rear one. Such difference
between the values of the spacer compression will introduce some change in the arrangement of pole pieces.
maximum value of the difference due to the spacer compression is 0.04 mm for parallel alignment and is less than
0.05 mm for defect of the median plane, but such differences entail no problem on the beam dynamics. For theabove mechanical analysis the magnet was treated as a solid structure, notwithstanding the magnet consist of 12
separate parts. This treatment is justified for high excitations when different sections of the separate parts are

The

166

80

000 !--- - - - - - - - - -- - -- - 0.02

~ I'

Fig. 3. Computed
deformation of the sector
magnets under maximum
load conditions.

The

vertical scale is expanded
by a factor of 400.

~rz:2 Spacer

0

500

1 000

1 500

2 000

2 500

Spacer

IZZ'll

3 000

3 500

Radial distance from inner edge along oenter line of sector magnet

Fig. 4.

Computed vertical deflection of the polefaces and the median plane along the centerline of the sector magnet. (HARA's FEM-2)

held together by strong magnetic forces between their interfaces. More detailed computations for the mechanicaldeformation and beam dynamics are now in progress.
Trim coils
For the design of the trim coils extensive calculation by TRIM code were performed. Then a quarter sizemodel was made and field profile has been measured iteratively. Measurements using this model were carried out toobtain the strength and radial profiles of the induced field by trim coils with different coil widths and intervals.
In order to obtain the coil configuration and required current of the coils , computer optimization with combinationof the above data were tried to form isochronous field. The result obtained was that the maximum deviation fromthe isochronous field can be made as small as 0.06 %. The resultant phase defect was estimated to be less than one
degree.
The trim coils of the SSC magnet consist of 20 pairs of cup per plates for isochronous field and 10 pairs ofhollow conductors for harmonic field. They have a curved shape for hard-edge pattern of the equilibrium orbit.
A preliminary design and configuration of the trim coils is shown in Fig. 5 and required currents of the trim coils
are also indicated for the case of r = 1.20 (proton). Five power supplies are needed to achieve the isochronous
field. Total power of the trim coils is estimated to be 280 kW.
Detailed design study of the trim coil system is now in progress.

Fig. 5.

Trim coilnummber

Radial
width
(mml

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20

14
130
114
242
232
242
287
270
128
185
175
148
143
124
113
114
99
88
85
63

Current
f or
Radialy= 120
gap
( AJ
(mm)

5

8

500
100
500
100
300
400
500

5

510
450

Configuration of the trim coils for isochronous field , showing required currents for 'Y = 1.20.

167

11-3.

Design Study of the Canted Injection Scheme
for the IPCR SSC (I)Y. Yano , A. Goto, T. Wada,
N. Nakanishi, and N. Kishida

We have made a full report on the design of the beam injection system for the IPeR SSein Ref. 1, in which the beam is injected radially through one of the open valleys of the SSC. Aftersome study on this system, we decided to modify the design as shown in Fig. 1. In the present
design , the beams transported from the pre-accelerators are injected vertically down into the open
valley and inflected onto the median plane by a couple of 45° bending magnets (BM3 and BM2) .
After this vertical inflection of 90° the beam is radially guided to the first acceleration orbit bymeans of a bending magnet (BM 1), two magnetic inflection channels (Mle2 and Mie 1) and anelectrostatic inflection channel (Eie). The Mies are inserted between the poles of the sector
magnets to add the necessary bending power to the sector field. The characteristics of these
injection elements are listed in Table 1. We call the present system "the canted injection system".
Its advantage is that the beam focusing elements can be arranged down to the central region of
the sse. In radial case, no such elements are allowed to exist along the injection trajectorythrough the long valley region where beam is being accelerated. The circumstance that the beamline of the linac as the pre-accelerator is about 20 m higher than the median plane of the sse isalso one of primary factors for our decision.
QM : Q Magnet
ST : Magnetic steerer
BIV1 : Bending magnet
MIC : Magnetic inflection channele
EIC : Electrostatic in flection channel
PM : Profile monitor
DP : Differential probe

0.5

lm

Layout of injection elements in the central region of the SSe.
Fig. 1.
The injection trajectory drawn through STl , ST2 , and QM is in the plane
perpendicular to the median plane.

168

Table 1.
Element

Bend angle

Characteristics of injection elements.

Aperture (em)Radius (em)Maximum field

Face angle(en trance)/ (exit)

46
46
43
48
450

17.1
kG
17.1
kG
(15.2)+3 kG(15.2) + 1.2 kG
62
kV/cm

22.5/22.5
14/-13

~

BM2
BM1
MIC2
MIC1
EIC

45°
ll0°
86.9°
37.2°
3.6°

(H)

(V)

10
4
3
3
2

4.2
4.2
4
4

0/0
0/0

Besides the principal role to guide the beam onto the first acceleration orbit, the injection system
also must satisfy some conditions that are imposed upon the beam at the injection point. These
functions are indispensable for one to get well-centered acceleration orbits for particles with wide
range of mass and energy , and to extract the beam efficiently. What are to be adjusted for the beam
are the position and direction, the dispersion in radial direction, and the beam ellipses in six
dimensional phase space. The injection system should be so designed that this matching procedurecan be done as easily as possible. The adjustment of the position and direction of the injectedbeam can be accomplished by the movable MICs and EIC whose location and direction are
remotely controlled. Face angles of BM 1 are determined so that the necessary radial dispersionof the beam may be obtained. For the easiness in matching the beam ellipses with the eigenellipses of the sse, the properties of the injection elements in the beam optics are desired to be
independent of the change of the bending field strength. The quadrupole magnet (QM) between
the 45° bending magnets makes the achromatic transport of beam possible.
A 1I 1-scale model of BM 1 whose bending angle is 50° has been built. The map of themagnetic field produced by this model was obtained. The experimental results for this model test
are reported elsewhere in the present progress report. By using the measured field data for thesector magnets and BM 1, a more realistic study of the beam injection has been done in terms ofnumerical orbit calculations (see "Design Study of the Canted Injection Scheme (II)"). The MICs
were designed to consist of iron shims and septum coils. A model of MIC has been built and theCompensati on co iI

MIC coil

Iron shim
Copper holl ow conductor

9X9- 6¢
Insulator

Fig. 2.
MIC cross-section; dimensions in mm. The thickness of the ironshim will be determined from the magnetic field measurement for the model
MIC.

169

An odeCathode

I

20 1

40

40

1

20 1

Fig. 3.
EIC cross-section;
dimensions in mm.

measurement of its magnetic field will be made in November, 1980. The EIC is of conventional
structure. The cross sections of the designed MIC and EIC are shown in Figs. 2 and 3.

Reference
1)

Y. Yano: Sci. Papers I.P.C.R., 74, 13 (1980).

170

11-4.

Design Study of the Canted Injection Scheme
for the IPCR SSC (II)A. Goto, Y. Yano, T. Wada, and N. Nakanishi

For the detailed study of the injection trajectories, we have developed a computer program for the numericalorbit calculation. I)

In this program, the motion of charged particles in electro-magnetic fields is calculated withtime as the independent variable.

The fields of each injection element can be superimposed onto those of thesector magnets (the base fields) at arbitrary positions.

This program can deal with the acceleration of particles

and can calculate individually the paths of 17 particles consisting of a central particle and two groups of 8particles describing phase ellipses in both (r, r') and (z, z') phase spaces.
As injected particles to be used in the design of injection system we chose three kinds of particles, i.e. 0.84
MeV lu 238 U40 +, 7 MeV IU 12 C6+, and 4 MeV lu 12 C6 +.

The field data used are as follows:

The magnetic fields of2

the four sectors are given by the isochronous fields ) for each particle beam, which were calculated on the basisof the field data of the 1I4-scale model magnet. 3) The magnetic fields of BM 1 are given by those of the 1I 1scale model bending magnet. For the fields of MICs and EIC we adopted the analytic expression for fringe
field. 4 )The accelerating voltage of the resonators is given by the sinusoidal function of time.

We have designed the injection system in such a way that the beam is injected onto the equilibrium orbit.
The determination of the characteristics of the injection elements and their arrangement was made by tracing
the beam backwards from the middle of the open valley where EIC exists (the exit of EIC) through MICs up to
the entrance of BM 1.

Further, a certain number of acceleration orbits were calculated in order to estimate themagnitidues of turn separation (i.e. the radial separation between two central particle orbits) and beam separation(i.e. the radial separation between two beam envelopes).
Table 1.

Characteristics of injection elements derived with the numerical orbit calculation.
Parameters of BM2 are obtained with TRANSPORT.

Element

Bend angle

Aperture (em)

(H)

(V)

Radius (em)Maximum field

Face angle(entrance )I( exit)

BM2

45°

10

4.2

46

17.1

kG

22.5122.5

BM1

94°

4

4.2

46

17.1

kG

141-13

MIC2

84.5°

3

4

44

3.0

kG

MICI

35.2°

3

4

51

1.1

kG

OIO
OIO

EIC

2.9°

2

300

58 .0

kVIcm

The characteristics of EIC, MIC1, MIC2 , and BMI thus determined are listed in Table 1 together with those of
BM2 obtained with TRANSPORT code 5 ).

Figure 1 (a)-( c) illustrate the injection paths from the entrance of BM 1

to the exit of EIC followed by the first few turns for 0.84 MeV lu 238 U 40 +, 7 MeV lu 12 C6 +, respectively.

The

radial distances of the injected and the first accelerated beams from the machine center and their sizes at theentrance and exit of each element are listed in Table 2 together with the turn separations and the beam sparationsof those beams at the exits of MICI and EIC.

It was found that the positions of EIC, MICI and the exit of

MIC2 should be radially adjustable by 20, 8, and 3 mm, respectively, and that the beam separation of 29 mm at
the exit of MICl and 12 mm at that of EIC can be obtained even in the severest case.
assure the accelerated beam to clear these elements.

These beam separations

171

(a)

0. 84 MeV j u 238U40+(b )7 MeV ju 12C6+(c)

4 MeV ju 12ce+

50

l ODe nFig. 1 (a). Injection path through the injection elements and the first few acceleration turns of
0.84 MeV/u 238 U 40 +.
Fig. 1 (b). Injection path through the injection elements and the first few acceleration turns of
7 MeV/u 12 C6+ .
Fig. 1 (c). Injection path through the injection elements and the first few acceleration turns of
4 MeV/u 12 C6 +.

Table 2.

Calculated radial distances of the injected and the first accelerated beams from the machine center andtheir sizes at the entrances and the exits of injection elements together with their turn separations and238 40U +, 7 MeV/u 12 C6 +, and 4 MeV/ubeam separations at the exits of EIC and MIC1 for 0.84 MeV/u
12

Particle

238u40+C6 +.

The areas of phase spaces are set to be 25 1r mm·mrad.

0.84

---~

Injected orbit(width)1st ace. orbit(width)Turn separation
Beam separation
Injected orbit(width)

7

4

MIC2

MICl

EIC

Injectionenergy(MeV/u)

1st ace. orbit(width)Turn separation
Beam separation
Injected orbit(width)1st ace. orbit(width)Turn separation
Beam separation

Exit

Entrance

Exit

Entrance

Exit

856
(8.0)
919
(8.3)

862

925
(10 .8)
1041

869

820

877

823

871

823

{11.6)
117

63
55
836
(7.8)
856

106
846

967
(10.4)

(7.8)
20
12
847
(7.9)
887
(8.2)
40
32

927
{10.9)

40
29
855

926
(I 0.8)1003{10.3)

77
66(Units: mm)

172

References
1)

A. Goto, Y. Yano , T. Wada, and N. Nakanishi: Sci . Papers I.P.C .R ., 74 , 124 (1980) .

2)

N. Nakanishi and S. Motonaga: IPCR Cyclotron Progr. Rep. , !l, 12 (1979).

3)

N. Kumagai , S. Motonaga, K. Ogiwara, H. Takebe , T . Wada, and J . Fujita: Reports I.P.C.R., (in Japanese),

1i, 27 (1979).
4)

H. A. Enge: Rev . Sci. Instr. , 35 , 278 (1964).

5)

K. L. Brown , F . Rothacker, D. C. Carey , and Ch. Iselin: SLAC Report , No . 91 (1974).

173

11-5.

Model Study of the Injection Bending Magnet of the IPCR SSC

Y. Yano, H. Takebe, T. Wada, J. Fujita,
A. Goto , Y. Obana, and S. Motonaga

The injection bending magnet (BM1 ), one of the injection elements of the SSC is required to have the following
performances: 1) It can produce the maximum magnetic field up to 17.1 kG. On the other hand, its size must be
small enough so that it can be set in the limited available space of the SSC central region. 2) Its property in beam
optics must be independent of the change of magnetic field between 6 and 17 kG to allow easy injection orbit tuning.
We have designed this magnetO and constructed its 1/1-scale model with the bending angle of 50°. It is being tested
whether the designed magnet fills the above requirements. The dimensions of the pole and coil cross sections andthe pole profile at the beam entrance and exit are given in Figs. 1.2.
Figure 3 shows the magnetic excitation curve measured for the model magnet. While the current density ran

20
19
18
17
16

EXCITATION CURVE
Gap: 4.2cm
Number of turn s : 24
- - Air gap only

(3----TRIM•
Measured.J:::.

20

Fig. 1.

1

8 1 12 140. 1 1218 1

20Transversal dimensions (mm) of pole and coilconfiguration around beam aperture (upper half only).

...c.

noc:

l

c~

•

8

/A

.1·

~

{f)

-o
-~

u
:.;::;Cl>

Magnet ic efficiency

2::

A : 99. 1%( 14.2kG )B: 98.9%( 15.6kG )C: 971%(17.4kG )0: 95.4% ( 18.5kG )

c:
t:lD
ro

3

7

~ Upper yoke0

~ Upper pole00'1---~S?
'VIt--- - - +<..0

(Y)

(Y}

0

~~~~**~~~~~~~--4N
0
Jyl(,'----+--++-- - - + aj N~~~~~~~~~~~~~~~~~~0~~~-~
67.0( Meddian plane )Fig. 2.

Longitudinal profile of pole edge; dimensionsin mm. The curve of Rogowski is approximated by
combining six straight lines.

Fig. 3. Magnetic field strength vsmagnetomotive force measured for the model
bending magnet with the gap of 42 mm.
The data (solid circles) are plotted together
with the theoretical curve calculated bytaking only the reluctance of air-gap into
account (solid line) and that predictedby the TRIM code (dashed line). The
magnetic efficiency denotes the proportionof the measured field strength to thefield strength on the above solid line
at certain magnetomotive force.

174

up to 52 A/mm 2 when the magnet was excited to 18.5 kG, the maximum temperature of coils could be kept below
50°C with the water velocity of 3.9 m/sec. The estimation for the temperature rise of coils by the empiricalformulae 1) agreed quite well with the measured value.
For the detailed examination of the optical property of this magnet, the measurement of the magnetic field
distributions was made at 7, 12, 15, and 17 kG. The magnetic field strength was measured with the Hall generators
of BHT-910 series (F .W. Bell Inc .) that were of high temperature stability. The data in azimuthal direction weretaken automatically by using computer-controlled driving system. When(} is defined as the azimuth angle on the
inner side from the magnet edge and r as the radial distance taken from the assumed circular orbit centered in the polewidth , the map of magnetic field obtained was in the area of - 17 mm < r < +46 mm for -25° < (} < -3 ° and- 17 mm < r < +17 mm for -3 ° < (} < +25° . The mesh points were taken by a step of about 0.4° azimuthally andby a step of 2 mm or 3mm radially. The accuracy of measurements of field strength was within ±1.5 X 10- 4 .
Figure 4 shows the magnetic field distribution in radial direction measured at 6=25°, the central position of
the magnet in azimuthal direction. The uniformity better than 1 X 10- 3 was obtained in - 10 mm < r < +10 mm.

/1(0 ) =6.973k G--.fr-- 12. 130 kG-·-o--- 15.254k G- -x-- 170ll kG' 'x,,-5' x:,\

-o-

-10

\

\

I
I
I
\

I

- 15
- 20

-25

x

Fig. 4. Magnetic field distribution inradial direction measured at the azimuthof 25° to the inner side from the magnet
edge. r denotes the distance outer fromthe center of horizontal aperture.

r ' ( mrad )~~J--o-- 13 = 7kG- -x- - B= 17kG

X

r ( mm )z ( mm )Fig. 5. The phase ellipses in both transverse directions at exit of the 90°
bending magnet for the beam just after passing through the magnet.
Leave the detail to the text.

175

This was just as we had expected in the design study including the estimation of field uniformity required for beam
optics. The further examination was performed by tracing a beam through the measured magnetic field in termsof numerical orbit calculations. Because the magnet (BM1) will have the bending angle of about 90°, we havegenerated the magnetic field of a 90° bending magnet on the basis of the model data. The measured data wereused in the region of - 25° < (] < +25° near both edges of this 90° magnet and the radial field distribution
throughout the central region was assumed to be the same as that at fJ = 25°. In the numerical calculations,a beam starts from a position 46 em, which is equal to the radius of curvature of this magnet, apart from one sideof the magnet edges and passes through the magnet. At the starting position the beam is assumed to have phase
ellipses of circular shape of 5 mm X 5 mrad in both transverse directions. The transformation of phase ellipsesof the beam was calculated at exit boundary of the 90° magnet. Calculation was made for the maximum fieldstrengths of 7 kG and 17 kG. Quite satisfactory results have been obtained in which the shapes of ellipses were
found almost same inspite of the large change of field strength as shown in Fig. 5.

Table 1 gives the variationof the position of effective boundary and the effective bending angle with change of magnetic fields for thismagnet. Only negligible change of the above quantities was seen. From the present study, the designed magnet
has proved to have sufficient performances as the injection bending magnet.

Table 1.

The variation of the position of effective boundary (xeff) and the effective bending angle(fJbend) with different magnetic field strengths for the 90° bending magnet. The map ofmagnetic field of this magnet was generated on the basis of the field data measured for the

50° model magnet. &eff is defined as the displacement to the outer side from the magnet
edge. &eff and ~(]bend denote the maximum variations of xeff and (]bend' respectively.

B (kG)

xeff (mm)8 bend (deg)

6.973

-0.42

89.89

12.130-0 .5089.86

15.254

-0.39

89.89

17.011

-0.37

89.90

&eff (mm)0.1361} bend (de g)

0.04

Reference
I)

Y. Yano: Sci. Papers I.P.C.R ., 74, 13 (1980).

176

11-6.

Magnetic Field Measuring System for the Model
Injection-Bending Magnet of the SSC

H. Takebe, Y. Yano , T. Wada, J. Fujita,
Y. Obana, and S. Motonaga

An automatic measuring system of magnetic field was constructed to measure the magnetic field of an

injection-bending model magnet.
This system consists of a mechanical part, two Hall generators and electronic devices, an NMR gauss meter,
and a microcomputer, LSI-11. Figure 1 (a) shows a schematic diagram of the system, and a setup of this system isshown in Fig. 1 (b). The relative accuracy of the set of field measurement was found to be better than 2 X 1o- 4
for a period of a few days and the absolute accuracy of 1 X 1o- 3 for in the period over four months was obtainedusing a Hall generator, BHT-910, without a temperature stabilizer. The mechanical part and the procedure for thecalibration of the Hall generator are described below.
Two Hall generators are mounted in a probe assembly together with a Pt-thermometer. The probe assemblyis fixed on a goniometer which is driven by a pulse motor controlled by the computer. The radial position of theHall assembly is changed by replacing a fixed point of the probe assembly on the goniometer. The position of thegoniometer in the azimuthal direction is detected within the accuracy of 0.15 mm along the arc path using an
optical rotary encoder.

I'OSITION
REA DOU T

II ALL

GE~EiiATOiiSTIIER'diSTEii

Fig. 1. (a) Schematic diagram of the system for the magnetic field measurementof the injection-bending model magnet.

Fig. 1. {b) Setup of the system.

177

Two Hall generators are powered in series by a 100 rnA current regurated power supply with a stabilityof
1o- . Figure 2 shows an example of stability check of the system at the field of 11.8 kG. Magnetic
field, currentof the magnet coil, temperatur es of the magnet coil and the probe assembly and Hall voltages areplotted by thecomputer. The error in the measurement of the Hall voltage was found to be better than 1 X 1o- 4
for an hour.
The Hall voltage was calibrated with the NMR gauss meter. Calibration was made at field intervalsof approximately
1.5 kG from 3 kG to 18 kG by changing temperatur e of probe assembly from 20°C to 35°C in stepof 5°C. The
data was fitted to the 5th-order polynominal relating to the Hall voltage and magnetic field. Figure
3 shows thedifference B-Bcal plotted against B, where B is the magnetic field obserbed by the NMR gauss meterand Bcal thefield obtained from the observed Hall voltage by the above least-squares fitting. The relative accuracy
was foundto be 2 X 10- 4 for one Hall generator (No. 3186) and 1.3 X 10- 4 for the other (No.3187) at fields
larger than2.5 kG.
In order to check the long term stability of the system, measurements of Hall voltage against themagnetic
field were performed over ten times from April to July. The difference VH-V cal is plotted aginst
Bin Fig. 4.
5

1

1--+-t-+---1-+- -+c..ulL CURREST mc cn f---+-t-+---1----l--- +---1

f--+-t-+----1-+--1 Hl\l.l VOL"l M.;E :s 31116tl-+-!-+---l--+-- -+-----1
j

VV\

~I

\I\

v

ll

~r~~i-IALLroLTAGE( : 3 186t

1\

B ; Magnet ic field

Fig. 2.

Characteristics of the magnetic field measuringsystem.

Resolution of the Hall voltage is about 10- 4

at the digital volt meter resolution of 1 J1V at 11 m V
in the field of 11.8 kG.

\>

BHT 910-3186-.3

Fig. 3. The difference B-B cal against themagnetic field observed for different
temperatures: o indicates the data for 20°C,
X for 25°C, 6 for 30°C, and • for 35°C.

•1 0 - 3

~

..
I

~

15kG

~~~~~~~~~--~----~:~-- 4

- 10

f 4L~

5kG

0

-...·-·_--=4'-'=[::----c.c..1---t--_t-~~_--.-_-___.__
B_+----.~~-=--=---10~- 10 - 3

A•x

5. Apr. 18°C
18. Apr. 18°C
21. May 20°C•o

25. July 20°C
25. July 25°C

Fig. 4. Hall voltage change on standing. Points
indicate V H- V cal' where V H is the Hall voltage
observed for each measurement and V is the
ca1calculated voltage using 5th-order polynomin al
least-squares fits to the data on 18. April, 1980.

178

Veal was obtained from the 5th-order polynorninal fit to the data of 18. April.

absolute accuracy is better than I o- in the range from 7 to 18 kG.
calculation of beam trajectory.
An example of the results of measurements is shown in Fig. 5.
to complete a set of measurements.
3

As can be seen Fig. 4, the observed
This accuracy is satisfactory for theWith the present system it takes about 8 h

B (r) -B ( o )B( a )

X

IO'

10

I

!

B (l)}
B(a )

1.0

~)
B (o)

r (mm )

-20
I

/

·~'""

15 KG

f

18 KG

I
I
I
I
I

0995

I

I
I
I

cr:

I ~
I

~

~

I
I
I
I

20

- 10

w·
//(

-5

r

- 10

- 15

13 (o ) = 6.824 KG -uII 832f•::.J
7:

I
I

-15

<>---

- - -t:r----20

14.921

C!
<(

I

2

I

17.775

- 25

I

50'

10'

-

o·

-o

Fig. 5. (a) Azimuthal distribution of the magnetic
field measured along a circle of radius 460 mm
at maximum field of 7, 12, 15, and 18 kG.

-30

Fig. 5. (b) Observed variation of magnetic
field along the radius at the magnet centerfor the field of 7, 12, 15, and 18 kG.

179

11-7.

Microcomputer System with CAMAC for Measuring
Magnetic Field of a SSC Model Magnet

J. Fujita, T. Wada, and H. Take be

Measurement of magnetic field distribution of a model magnet of the SSC has been carriedout with an electronic system using OKI-4500 minicomputer. It was, however, difficult tooccupy the OKI computer long enough to carry through this measurement.
LSI-11 microcomputer system of DEC was, therefore, introduced.
systems are shown in Fig. 1 and Fig. 2, respectively.
The OKI computer system has been reported previously . 1 )A floppy based

Block diagrams of these two
Two NIM modules interface

the computer with general measuring instruments. Interconnection between a digital scanning
controller and the computer is performed by RG58A/U coaxial cables for control signals anda shielded 50 parallel wire cable for digital data signals.
X-Y
DISPAY
1300A/I

C. R. T

I

{\I;

1:
PRINT
COMMANDGAUSSMETER
r-DATA
f-G.M. DATA v
GAUSSMETER ( BCD) 46X 7
INTERFACE
5300

NMR

1\

rl r lXFER

START

STOP
8800A

IHALL

f-

DIGI TALARM INPUT

DIGITA L

BUSY

SCANNING

STOP)\ CONTROLLER DATA READY ( DR )Element

IPULSE
MOTOR

G.M. DATA or"' 7 RADIAL POSITION t..
46X7
DM.M . DATA
~
46X6
v
(
S TART

MUL TIMETER DMM DATA v(BCD) 46 X6
FOR WARD
BACKPULSE MOTORt- WARD
DRIVER
PDC-64~A"

COMPUTER
4500

REPEAT
E ND
P.M . FORWARD /,P. M. BACKWARD

~~

48kW

f P. M. MANUAL ADVANCE

~

30m

A_
~

FORWARD PULSE IN
BACKWARD PULSE IN

MAGNET
TAPE

OKI

RETURNJ.
COUNTER~MAGNETyDISKCONSOLE"r TYPE-

WRITER.It-

Fig. 1.

Block diagram of the electronic system using OKI-4500 for measurementof magnetic fields.
The LSI-11 microcomputer system consists of MOS RAM 28 K words, DSD400 dual floppy
disks with total storage capacity of 1 MB and a LA36 DEC writer. In addition to these basic
devices, three interface boards are installed in the LSI-11 bus. One is a DRY 11-B DMA
interface which displays data on a screen of a cathode ray tube through two digital to analogue
converters with a resolution of 8 bits. The second is an IBV 11-A that interfaces the LSI-11
bus with the instrument bus, or GP-IB bus, as descrived in IEEE Standard 488-197 5 Digital
Interface for Programmable Instrumentation. A FLUKE 8502A digital voltmeter is connected180

AMP CONNECTORS WITH MULTIPLE
POSITIONS ON A 19" RACK PANEL~

GP - IB BUS
(/)

:::)
(l)

>-

<t:

a

~

0

0

(/)
:::)

(_)

(l)

~

0:::

<t:

:::E
<t:

(_)

::::
I7J
_j

PLOTTERCONTROLLERandOKI DATA

K=======~

BUFFERCONTROL
SIGNALS

16 BITS1/ 0 DATA

TO/ FROM OKJ -4 500 I /0 PORT

Block diagram of the LSI-11 microcomputer system with CAMAC
Fig. 2.
installed for magnetic field measurement.
to the GP-IB bus. The third is a JLSI-1 0 crate controller of Schlumberger that interfaces theLSI-11 bus with a CAMAC dataway and is installed in a powered crate. All control signals
and digital data between the LSI-11 and measuring instruments are fed through CAMAC modules,
except those of the digital voltmeter. CAMAC modules are four BiRa 2322 dual 24 bits input
registers, two BiRa 3222 dual 24 bits output registers and a KINETIC 3061 16 bits gated I/0
register.

All signals from the 24 bits registers are distributed through 26 twisted pair cables

to AMP connectors with multiple positions on a 19" rack panel. Signals of each channel ofthe input registers are spread out to two connectors with 6 and 50 positions, and those from theoutput register are divided to three sets of eight bits, and distributed to three connectors.
data outputs from a 5300 NMR Gaussmeter, a 410A digital trendicator, a TR-6856 digital
voltmeter and a linear encoder are coupled to the 50 positioned connectors for the input
registers, and a READY signal necessary for the input register to latch data from the linear

Digital181

encoder is received through the 6 positioned connector.
Four NIM modules interface the CAMAC modules with specially purposed units. A dual
4 to 1 relay module switches analogue voltage signals generated by maximum four HALL
elements to the FLUKE 8502A digital voltmeter according to binary codes from the 3222 output
register. The digital scanning controller is modified to a Pulse Motor I OKI Controller whichtransforms D.C. pulses from the 3222 output register into A.C. pulses compatible to each unit.
8 Inputs OR/ Latch detects negative spikes or levels of up to eight inputs and holds these levels
until they are reset by a CLEAR pulse from the output register. A Plotter Controller / OKI
Data Buffer interfaces the KINETIC 3061 register with a IWASAKI DPL-602 digital plotter anddigital 1/0 ports in the OKI-4500 minicomputer whose selection is made by a switch on its front
panel.
All application programs for the measurements are developed by T. Wada on the basis of
RT-11 operating system provided by DEC. The microcomputer system with CAMAC showed
good performance in measuring magnetic field for a long time extending over a few days if
required by the application program.
Details concerning electronics of the measuring system will be described in SSC reports.

Reference
1)

T. Wada, T. Nomura, H. Kamitsubo, Y. Chiba, and F. Yoshida: IPCR Cyclotron Progr.
Rep.,]_, 83 (1973).

182

11-8.

Design Study of RF Resonator for the SSC

M. Hara, K. Ogiwara, and T. Fujisawa

In designing the RF resonator for the SSC at IPCR, resonators of three different types were
investigated.

These are a resonator of a single gap type, a A./4 type with a single vertical stem,

and a A./2 type with two vertical stems in opposite sides.
H 101 mode rectangular parallelepiped.
value.

The first one is the variable frequency
This is expected to have a simple structure and high Q

In our case, however, it is difficult to realize because of the following reasons.

The
injection radius is so small that the spatial restriction near the central region makes the voltage

at the dee gap low near the injection orbit (about a half of the maximum voltage at most).
Moreover, compared with other types, a voltage twice as high is needed to keep the same energy
gain per turn, and this demands wide gaps.
use of large harmonic number.

The relatively high cutoff frequency requires theThen transit time effects become severe.

The second one has some advantages but detailed analyses have proved that it has fatal
drawbacks which is shown elsewhere. 1 ) The third one is supposed to be realizable.
The half wavelength resonator is designed under the following conditions:1)

The frequency range is 17 to 45 MHz for the synchronous operation with the injectors.

2)
3)
4)

Harmonic numbers are 9, 6, and 4.
Maximum energy gain is 1 MeV/turn per unit charge.
20° delta shaped two dees are located at opposite valley spaces between 50° sector

magnets.

SHORT
END

SECTION A- A'

STEM

Cross sectional views of the half scale half
Fig. 1.
wavelength resonator. Hatched part is cut off toimprove the radial RF electric field distribution.

183

•
~

.

·~ ........___.

Q)

10~

ao
~ 0.9
0
>

Calculated val ues-----------------

Q)
Q)

20 000

0
Q)

::>:

·~

___.......~

Frequency=70.72 MHz·~•----·-·-·

0.8
0.7

-+-'

10 000__Frequency = 81.06 MHz

cu
"'ill

0::

5 000

1 0 ~~

· ~
0.9
0.8

(ij

·;;;::

~ 0.1

1 000

·--.

Frequency = 45.16MHz

----~

•
·-·---

C1u

10 ~=-----------=-----~~~~---Frequency = 31.17MHz. --·--.
1-·-------·---·

0.9
0.8

3
Frequency ( MHz)

Measured and calculated Q values
Fig. 2.
and stem lengths. Q values are measured
by decay time method. Dotted lines indicate
calculated values.

Injection

5

7

9

11

Position along accellerating gap

13
Extraction

Relative distribution of RF
Fig. 3.
electric field along the dee edge ofhalf scale model resonator.
Measurements were done by perturbation
method using ceramic block.

Radial length of the accelerating gap should be longer than 2.6 m corresponding to the
distance between injection and extraction radii.
6) Maximum current density at short ends should be less than 50 A/em.
5)

Compact , simple in structure and easy to handle.
8) A constant or radially increasing voltage distribution is desirable. - -Calculations based on the distributed constant circuit theory were done for three types of stems,
the cross sections of which were circular, rounded triangle and racetrack. The racetrack stem
7)

was found to be favourable.
A half scale model resonator was constructed to investigate RF characteristics. This modelis shown in Fig.l. At several stem lengths, resonance frequencies, Q values, and the radial
distributions of RF electric field were measured and shown in Fig. 2 and Fig. 3. The RF
electric field distributions had maximum at small radial position and this was not desirable.
In order to improve the distributions, parts of the stems are cut off as shown in Fig. 1 (hatched).
Data shown in Fig. 4 indicate fairly good results.
In conclusion , the calculation and measurements show that the half wavelength resonatorwith double vertical stems satisfies the desired conditions. We are developing a computer code
to solve the problem of three dimensional electromagnetic wave in a resonator on the basisof finite element method in order to obtain the radial electric field distributions.

184

Radial length of dee
Radial length of stem
1.2

Frequency =79.87 MHz

0.8

Q)

1.2

Frequency = 75.98MHz

tlO

~
0

~

l .Oo---a::,--- - - - - - ---o/---- -

Q)

u
a;

~

0.8

Qj

a::

11[

Frequency= 56.7 MHz

1.0

0.9
0.8

Fig. 4.
Relative distribution of RF
electric field along the dee edge for the

:::::
11

Injection

Position along accellerating gap

13

Extraction

cut-off model resonator.

The electricfield at the extraction radius became
strong, and the distributions were
improved.

Reference
1)

K. Ogiwara, T. Fujisawa, and M. Hara: IPCR Cyclotron Progr. Rep., !___±, 187 (1980).

185

11-9.

Design Study of Oscillator for the SSC

M. Hara, K. Ogiwara, and T. Fujisawa

The design study of RF system for the SSC is performed. The resonator is described
elsewhere. 1 ) RF amplifier and coupling system between the power amplifier and the resonatorare designed according to the following conditions:1)
2)

The frequency is variable from f min = 17 MHz to f max = 45 MHz.
The maximum output RF power is 300 kW.

Two oscillator systems are considered; one is a self-exciting system and the other is MOPA
(master oscillator and power amplifier) system. The latter is employed because of the necessityof synchronous operation with the injectors (the linac and A VF cyclotron). The oscillator isdesigned intending to use a tetrode, which is to be chosen among RCA 4648, Eimac 4CW-250000
and Eimac X 2170. Length of more than 2 m for the feeder line is necessary from the power
amplifier to the resonator. Only a traveling wave should be excited on the feeder line because
the frequency must be variable and the feeder line is so long. The circuit is schematicallyshown in Fig. 1. The impedance of the power feeder is fixed to 50 n for convenience' sake.
The impedance matching between the resonator and the feeder line can be obtained by a variablecapacitor (Cf). Figure 2 shows the expected shunt impedance of the resonator and thecorresponding coupling capacitance for impedance matching. The impedances can be matchedbetween the main amplifier and the feeder line by a variable capacitor (Cv)· The tuning of plate( pF )

1.0

0.5( kQ )

400~----- ------ ,

I
I
I

Lo

200

I

T0
I

L----- - - - --ReSOnatOr

RF power feeder line andFig. 1.
impedance matching circuit for thesse.

Frequency (MH z)

Fig. 2.
Coupling capacitance(Cf) to
give the impedance matching between
the resonator and the feeder line
(50 D). Calculated shunt impedances(Rs) of the resonator are also shown.

186( pF )

100(a)

Cv-Frequency( b)

Lp - Frequency( ,uH )

Fig. 3 (a) The capacitance (C v ) to give

0.5

17 20

30
Frequency ( MHz)

40

45

the desired plate load resistance (Rp)·(b) Stub inductance (L p ) to tune theplate circuit.

circuit is done by a tuning stub (LP). The expected values of the stub inductance (LP) and thecapacitance (Cv) are shown in Fig. 3. The impedance matching at the grid of the tetrode isunder consideration and testing. A feeder and an oscillator for a model resonator 1 ) are underconstruction to investigate RF circuit characteristics.
In conclusion, power feeder and main amplifier can be realized with the above statedparameters.

Reference1)

M. Hara, K. Ogiwara, and T. Fujisawa: IPCR Cyclotron Progr. Rep.,!±., 182 (1980);
K. Ogiwara , M. Hara , and T. Fujisawa: ibid. , p. 187.

187

11-10.

Measurement of RF Field Distribution for a Quarter
Wave- Length Vertica I Type Resonator

K. Ogiwara, T. Fujisawa, and M. Hara

The half wave-length type resonator for the SSC was investigated last year.l)

We alsostudied a quarter wave-length resonator this year because it has advantages that the resonatorbecomes smaller in size and simpler in structure, resulting in lighter vacuum pumping load.
However, the model-study described below revealed the following problems:(1) Vertical electric field may be induced at the accelerating gap and may, further, leakout inside the dee.
(2)

At the accelerating gap , the electric field has different strength above and below themedian plane.
A half-scale model resonator of a quarter wave-length type was constructed 2) and theelectric field distributions were measured by the perturbation method using a celamic block inorder to eliminate the disturbance from RF magnetic field. Figure 1 shows the field measuringsystem for this resonator. Figure 2 shows the vertical distribution of the RF field at theaccelerating gap. It was found that this resonator had different field strengthes above and below
the median plane at the accelerating gap. Figure 3 shows the horizontal distribution of the RF
field. This resonator was found to have large RF electric field even inside the dee, of which thestrength was about 60 % of the dee gap field at the intermediate radius when the resonator
was excited at 67.5 8 MHz corresponding to 33.79 MHz in the case of a full-scale resonator.
In order to understand the experimental result, we have also calculated the field distribution
inside the dee by assuming that the dee is the rectangular wave guide for simplicity (the electricfield is given at both ends). In Fig. 3, the calculated results are shown. The experimental
tendency is reproduced fairly well. The field inside the dee must be induced by the RF
electric currents flowing above and below the dee aperture.
A. I 4 Type model cavitylThese fatal drawbacks are due toDriving system

Positi on signalof a celamic block

Dee

Stem

Fig. 1.

The block diagram of the field measuring system forthis resonator.

188

Frequency= 51. 17 MH z
1.5
Cl5

c(I)

x

:Minimum radiuso : Mean radius0.

• : Maximum radius

C::
(I)

'-6
<l)

E
<l)

-:S
<U
-o
<l)

1.0

~
(I)

E

0

z

-o
Qj

'-(I)

u

·_.:;

Q.i
>

<l)

::::
+--'
(I)

Qj

0:::

Fig. 2.
40

30

20

10

0

10

of the RF field at the accelerating
gap.

30

20

The vertical distribution

Median plane (em )Frequency = 51.17MHz

1e
2c
Qj

Electric field at dee gap

0. 5

Electric tiel d inside the dee.

<l)

>

+--'
(I)

Qj

0:::

3

5

7

9

11

13

Electric field at dee gap.
Electric field 1nside the dee.

Fig. 3.

The horizontal distributionof the RF field. Relative field
distribution at the accelerating gap andinside the dee are shown. The broken
line shows the result of calculation.

!nj ection

Position along accellerating gap

Extraction

asymmetric structure of this resonator, and made us give up the idea of using a quarterwave-length type resonator.

References
1)

H. Nakajima, K. Ogiwara, F. Yoshida, and J. Fujita: IPCR Cyclotron Progr. Rep., _U, 16(1978).

2)

K. Ogiwara, F. Yoshida, H. Takebe, and T. Fujisawa: ibid., g, 10 (1979).

189

11-l 1.

Some Properties of Accelerated-Beam Orbit

in theSeparated-Sector Cyclotron

N. Nakanishi, T. Wada, A. Goto, and Y. Yano

A computer code AO for an accelerated-beam orbit in the separated-sector cyclotron SSC has
been developed 1) and some calculations on the properties of the orbit have been done. The
isochronous field, which is employed in the calculation, is numerically produced by an equilibrium
orbit code E0 2 ) using the magnetic field measured in a model magnet. Since the model magnet is
not exactly of a 1/4 scale in the radial direction, the magnetic fields are not only scaled up but
also expanded to those of the full scale magnet. The frequency and position dependences of theaccelerating voltage along the gap , which are employed in the calculation , are obtained by using
measured data in a model cavity. In the calculation the maximum voltage along the gap is set
to be 250 kV. Since the azimuthal angle was taken to be an independent variable in the numericalintegration, accuracy in the calculation became worse toward the larger radius. This defect wasremoved considerably by an improvement in amending the integration method 3 ) without muchincrease of the calculation time.
Some results of the calculation will be described in brief. Injection conditions of anaccelerated reference orbit should be determined to minimize the oscillation amplitude of the turnseparation. The turn separations of an accelerated p+ beam at the injection energy of 9 MeV
are shown in Fig. 1. The beam is transported from an injector cyclotron and accelerated up to
the energy of 184 MeV at the harmonic number h = 6 in the SSC.

As can be seen, the amplitudeof the turn separation is nearly 1 em in the case of injection onto its first equilibrium orbit.
However the amplitude is reduced to zero if the beam is injected under a specific condition.
The radial displacement and radial component of momentum are taken to be, respectively,
0.0 em and 0 .00215 cyclotron unit against the first equilibrium orbit at the injection point,
p+ Ein =9MeV

E
0
c

0

C1J

~ 2.0

Q)
(f)

c

~
1-

0.0

50

0

250
No. of turns

Fig. 1.

Turn separation of accelerated p+ beam.

The broken

and solid lines show the cases with and without optimization of
injection conditions, respectively.

190

and the initial phase is set to be -4.0 deg. Here zero deg is taken to the phase at which therising RF voltage crosses the base line. In general these conditions are different for various particles
and various injection energies.
Behaviors of the beam in the 6-dimensional phase space ate shown in Fig. 2 for the p+ beam.
These curves show transformation of phase space pattern when the beam is injected on to the firstequilibrium orbit in the center of the open valley. In this calculation the reference orbit andtypical eight orbits on the eigen ellipse are traced toward the extraction region. Figure 2 (a), (b),and (c) show the phase patterns for the (x, x'), (z, z') and (6E/E, 6l{J) spaces, respectively.
Emittances are assumed to be Ex z = 20 mm·mrad and 6E/E· bp = 0.0015 X 1.5 deg. In these'in each phase space only is taken into account at theexamples, the two-dimensional spreadstarting point. The contribution of the spread in the radial phase space to the behavior in the(.6E/E, .6l{J) space is shown Fig. 2 (d).
p+ 9MeV

<:x,z

LlE

y

= 20mm mrad

·Ll<p =0.00 15·1.5deg.

( a)

z'

Transformation of phase spacepattern projected on the (x, x') plane (a),Fig. 2.

3o 6o 9o T2o l5o 180 ( MeV )

9

28

0

71

115

158

200

242 (Turns )(z, z') plane (b), (6E/E, bp) plane (cand d).

The isochronous magnetic field is composed of the fields induced by the main magnet andtrim coils which are mounted on the magnet pole faces. The maximum deviation .6Bmax =IB(r) - B0 (r) Imax between the real and ideal isochronous fields should be suppressed to avalue as small as possible. In order to estimate the permissive tolerance, a simple model isintroduced. It is assumed that the radial variation induced by the trim coils can be expressed by asinusoidal curve
B (r) ~ B (r ) [ 1 I
0llB~ax sin {2a" ( r - r

0) -1 cp

0

}

J,

191

where B(r) and B0 (r) are the real and ideal isochronous fields, respectively, and B 0 is set to beideal field strength at the injection point for convenience sake. Variables a, r 0 and ~Po are wave
length, injection radius, and initial phase, respectively. The phase slip induced by the fielddeviation is calculated for the 4 MeV I A c 6+ beam. The relation between the deviation amplitude
and the wave length is shown in Fig. 3 for the cases giving the phase slips of less than 1 and 2
degs. The initial phase i{)o, which corresponds to the deviation at the injection point, is required
to be as small as possible. The value is set to be zero in this case. The phase slip can be
estimated for more complicated patterns of the deviation, too.

E

~

40
20

Fig. 3.

o~--~o.~o~2--~o.~o4~~o~.o~6--~o~.os---o~.-l--­

Ll£

£

( %)

Relation between the fielddeviation amplitude and its wave
length at the phase slip of less than
1o and 2°.

References
1)
2)
3)

N. Nakanishi and S. Motonaga: IPCR Cyclotron Progr. Rep., !1, 12 (1979).
N. Nakanishi and S. Motonaga: ibid., .!1_, 18 (1978).
A. Goto, Y. Yano, T. Wada, and N. Nakanishi: ibid.,.!.±, 170 (1980).

192

11-12.

Design of Beam Transport System for the IPCR SSC

N. Kishida, Y. Yano, and T. Wada

The beam transport system for the accelerator complex of the IPCR heavy-ion facility has
been designed . This complex consists of a separated-sector cyclotron (SSC), RILAC (Riken
heavy-ion linac facility) and an A VF cyclotron. RILAC and the A VF cyclotron function as
pre-accelerators. The beam lines of accelerators are not on the same horizontal plane and a three
dimensional layout is taken into account. Horizontal and vertical distances between RILAC andthe SSC are about 25 m and 19 m, respectively, and those between the AVF cyclotron and the
SSC are about 25 m and 8.5 m, respectively. The designed beam transport systems are shown in
Figs. 1 and 2. The systems consist of two kinds of quite symmetric subunits. One is anachromatic bending section and the other is a straight beam guiding section with some quadrupole
magnets. Charge stripping and charge selection parts are installed between SLO and SL2 ( cf.
Fig. 1) and between SCO and SC3 ( cf. Fig. 2) in order to decrease the magnetic rigidity of preaccelerated ions and to increase the attainable maximum energy of the SSC. The horizontal andvertical phase-space matching is performed in the section between SL 10 and SL 11, where the beamis achromatic. Dispersion matching is carried out in the subsequent beam injection system.n
The calculations of ion-optics in the beam transport system have been made with the aid ofcomputer program TRANSPORT. 2 )
QS
QD
QT

This program is based on the matrix formalism for the beam

: Quadrupole Singlet: Quadrupole Doublet: Quadrupole Triplet
from RILAC

STP : Charge Stripper
SLIT : Silt Sytem

SL O(STP)
QDl
QD2' Sll (SLIT)
QD3QD4SL2 (B)Dl

P : Beam Profile Monitor
E : Emittance Measuring Device
B : Buncher
E
0'>

ci

,..--<QTl

SL9(E) QD13
D9
QT8
DlO
SLl O( P) QDl 4
QS4 QS3QS6 QS5
Sll l( E)to beam injection system

Layout of the beam transport system from RILAC to
Fig. 1.
the SSC. The entrance of the beam transport system (SL 0) is
about 15 m distant from the exit of linac. The beam line fromthe AVF cyclotron flows into this system at switching magnet
D8.

193

QS

: Quadrupole singlet

P : Beam Profile Monitor

QD
QD: Quadrupole Doublet: Quadrupole Triplet

E : Emittance Measuring Device
B : Buncher

STP : Charge Stripper
SLIT: Slit System

SL6 ( P)

Fig. 2.
Layout of the beam transportsystem from the A VF cyclotron to the SSC.
optics. The calculations have been performed within the first-order approximation. Further,
the second-order calculations have been also performed in order to estimate aberrations. Every
subsystem before the beam matching section is formed by a double-telescopic transport system
whose transformation matrix is the unity or negative unity diagonal one.
As an example, the structure diagram of charge stripping and charge selection part from SLO
to SL2 is shown in Fig. 3. This system is also a 90° -bending achromatic transport system witha mirror symmetry with respect to the point SL 1. Figure 4 shows that 238 U40+ and 238 U 39 +
105.9

0
__j
(j)

<t:

OJ

0a a0
Unit: emfJ ' = pz=60cm

a, = az = 45 •f] , = /:12 =,i, =rl. = 22.5.

Strength of magnets for ""U' 0 • of 0 84 MeV/ u

Dl. 02 : 13.088 kG
QDlA, QD4B: - 10148 kG/ em
QDlB, QD4A: 0.95019kG/ cm
QD2A, QD3B:- 0 14675kG/ cm
QD2B, QD3A : 0. 46867 kG/ em
R ( SLl+--SLOl : R, z= R21 = Ro = Rzs = O
R ( SL2<--SLOl = I (unity matrix l
SLO: charge stripper
Sll : charge selection slits

Fig. 3.
Charge stripping and charge selection part with two rectangulardipole magnets and eight quadrupole magnets in the system I. This isalso a 90°- bending achromatic transport system.

194

CD
N

-

CHA RG E STRI PPE R AND CHARGE SELECTION PART
0.84 MeV/ u
SIN GL E RAY
X= 2. 00 NN. DX=l 2.50 NR .
Y=O.OO NN. DY=O .OO NR. DP= D. OO/.

0

0
CD
01

c

w
~

0II)

0
f'-

ID

0-

0

0

0

-

a:

<(

ClJ

0

0

,........

0,........

a

0

a

<(

ClJ

,........

N

N

0

a

a

0

0

<(

ClJ

(Y)

(Y)

0

0

a

m o

c:
o

~

,;, ,;

,.:

<(

N

a

II:

ClJ

'<j"

'<j"

0

0

a

0

c:

m

a

N
_j
(f)

_j
(f)

.;
I
0

"

:;l

"

" "

"

0

0

0

-

0

~ 0

~

0

0

0

0

0

0

0

""'

0
I

~

Fig. 4.

I

0

~

D

~

~

~

j~

Single ray plot for the 238 U40·+ and 238 U39 + beams of 0.84 MeV/u.

Both beams are clearly separated at the charge selection slit S2.

This figure

also indicates that this system is an achromatic system.
beams whose object sizes are 0.4 em are clearly separated at the charge selection slit (SL 1).

The

distance between two beams is about 2.5 em.
The more detailed information has been published in Ref. 3 .

References
1)

Y. Yano: Sci. Papers I.P.C.R. , 74, 13 (1980); A. Goto , Y. Yano , T. Wada , and N. Nakanishi:

2)

ibid., p.l24.
K. L. Brown, F. Rothacker, D. C. Carey, and Ch. Iselin: SLAC Report,No. 91 (1974).
N. Kishida, Y. Yano , and T. Wada: Sci. Papers I.P.C.R., 74, 105 (1980).

3)

195

11-13.

Vacuum System of the SSC ( I )Vacuum Considerations in Some Aspects

S. Nakajima and K. Ikegami

An accelerator chamber is designed for the separated-sector cyclotron (SSC).
considerations for the chamber are as follows:

VacuumPressure in the chamber
Beam loss in an accelerator can be estimated from the following relation:1)fai X Pi X Xi)
N(X) = N 0 exp ( - 3.54 X 10 - 16
where N 0 is the number of incident particles and N(X) is that of surviving particles after travelling2) is the cross section which describes the beam loss due to ana.(cma distance of X.(cm).
11interaction with any remaining gas molecules.

is the pressure of the gas in question.
P.(Torr)
1

Because ai and Xi take various values depending on the species of the colliding particles and theconditions of acceleration, such a universal chart as that shown in Fig. 1 will be of considerable use
to estimate the required pressure in the chamber. Particles accelerated will move a distance of
N/ No=0.9

5

lo...
lo...

0

s
n...

n...

x

Fig. 1.

Relation between the pressure in thechamber and the travelling distance of theparticles.

ai or N(X)/N 0

is taken as parameter.

Fig. 2.

( km )

Pressure to secure 90% survival of

the accelerated particles as a function ofcross section, and total travelling distance inthe sse.

196

P (Torr)

Calculated attenuation for 23 8u37+

Fig. 3.

through the sse as a function of pressure.

When we can consider the value of a 1. to be almost constant during
acceleration, Fig. 2 will be more convenient. The shaded region will be available to the SSC.
It is seen that the pressure in the chamber should be kept below 1 X 1o-7 Torr to suppress theseveral km through the SSC.

beam loss to a value as low as 10 percent of the incident beam. Beam attenuation through the
SSC can be also calculated as a function of pressure. An example for 238 U 37 + is shown in Fig. 3
where ai X (V /C) is taken to be 1 X 10 -l7 cm 2 (V is the velocity of the particles and C is that oflight).
2)

Outgassing rate and pumping speed

We considered a plan in which the main coils .are placed outside of the vacuum chamber. The
total surface area exposed to the vacuum will be -550 m 2 for the chamber. The evolution ofgas from the constituent materials are estimated as given in Table 1. If we assume that leakage
through the chamber walls is 1 X 10-3 Torr·f/sec, the total outgassing rate in the chamber
amounts approximately 17 X 10 - 3 Torr·f/sec. The trim-coils on the magnets are not taken into
account in the estimation because the details of these system are not determined yet. It may bepossible to put them in the vacuum chamber. The gas evolution increases further in that case.

Table 1.

Component(Material)

Vacuum Chamber

Surface areas exposed to the vacuum and outgassing
load from these surfaces.
Surface area(m2)

Outgassing rate after
20 h pumping(Torr ·f/sec·cm 2)

Total outgassing
rate(Torr·f/sec)

180

2.5 X 10- 10

0.5 X 10- 3300

1.8 X 10- 10

0.6 X 10- 3

60

2.0 X 10- 8(2.1 X 10- 10 )12 X 10- 3(0.13 X 10- 3 )1.2 X 10- 10

3 X 10- 3(Stainless steel)Resonators(Copper)Magnets(Mild steel)(when nickel plated)

Elastomer seals

2.5

Total

550

16 X 10- 3

197

The major contributors to the degassing rate are the elastomer seals and the magnet poles composedof mild steel. It is desirable to use metal gaskets instead of elastomer seals if possible and tocover the pole surfaces with nickel plating. Even with such a procedure, the outgassing rate can
not be decreased to a value less than 6 - 7 X 10-3 Torr·l'/sec. Total pumping speed of 6 - 7 X
10 4 . l'/sec is therefore required to maintain the pressure in the chamber at 1 X 10 - 7 Torr.
Cryopumps and turbomolecu1ar pumps with high pumping speed will satisfy the demand.

Becauseconductance in the magnet gaps is very low (1 000 - 2000 £/sec, at the best), it is impossible
to exhaust the chamber through these gaps.
and every valley section of the chamber.

Pump will be installed to every RF resonator

198

11-14.

Vacuum System of the SSC (IT )A Preliminary Design of the Vacuum Chamber for the SSC

K. Ikegami, S. Nakajima, and Y. Ikegami

IPCR separated sector cyclotron, which is designed to accelerate all elements up to uranium,
consists of four sector magnets with a sector angle of 50° and a pole gap of 80 mm, two delta
resonators of half wave length type with a dee angle of 20°, injection and ejection systems, and avacuum chamber. The operating pressure required in the chamber for sufficient transmission ofheavy ions is less than 10- 7 Torr.l)
The vacuum chamber for the SSC should be designed by taking into accounts the following
conditions:
The chamber must accommodate the magnetic and electric injection channels of theinjection system at the central region.
2)
Space is narrowly limited between the sector magnet and RF resonator at central region.
1)

3)

To make overhaul or repair, the two resonators must be pulled out from the chamber.

In order to fulfil the above conditions, we have designed a vacuum chamber made of stainlesssteel which has the delta-shaped horizontal flanges to accommodate two resonator sections.
Figure 1 shows a plan view of the vacuum chamber for the SSC.

Cryo pump

Pump

EE 2 Deflector
Pump

ryo pump

RF Resmator

Fig. 1.

Plan view of the vacuum chamber for the SSC.

199

The size of the chamber is as follows:
diameterheight magnet and valley sections

9m
1.6 m

resonator sections

7.4 m
78m 3
550m 2

total volume
total surface area
Magnet section

Side flanges of the chamber are welded around the pole so that the main coil is placed outof the chamber. The size of the main coil is about 35 mm X 550 mm. The magnet section isconnected to the valley and resonator sections vacuum-tight by welding or elastomer seals. In
this case, trim coils of 32 pairs are in the vacuum. Figure 2 shows a cross-sectional view of the

Trim coil
Machinecenterreg ionFig. 2.

Cross-sectional view of the vacuum chamber for the magnet section .

Upper resonator

Chamber witha dummy dee
RF Resonator

Upper pde

VacuumCross-sectional view of theFig. 3.
vacuum chamber showing connection
scheme between the sector-magnet and
RF resonator sections at the minimum

Dummy deeradius.

200

vacuum chamber for the magnet section and Fig. 3 a cross-sectional view of the vacuum chambershowing connection scheme between the sector magnet and RF resonator sections at the minimum
radius.
RF resonator section
In the present design, the RF resonator section is made of three parts: the upper (lower)part of the section can be moved upward (downward) about 1 m to pull out from the main chamber.
Upper and lower parts will be connected using the elastomer seal to the main chamber section.
Pumping system
The pumping system of the SSC is composed of high vacuum pumping system and roughpumping system. High vacuum pumping system consists of cryo-pumps and turbo-molecul ar pumps
connected in parallel.

These pumping systems will be installed at the valley and resonator sections.

Reference
1)

S. Nakajima and K. Ikegami: IPCR Cyclotron Pro gr. Rep., 14, 195 (1980).

201

11-15.

Design and Operational Performance of Superconducting Coli
for Model Sector Magnet of the

IPCR SSC

N. Yasumitsu, T. Minakuchi, E. Toyota, and N. Kishida

At an early stage of the design of the separated-sector cyclotron (SSC) , it was intended toaccelerate the ions injected from the heavy-ion linac by using 8th harmonics. The maximum
field strength of sector magnets was 17.5 kG and the power necessary for the four main coils
was estimated to be about 1 MW. This power consumption was too large from viewpoint of thepresent energy circumstances. Thereupon we tried to adopt superconducting coils of the sector
magnets in order to decrease the power consumption.
A superconducting coil was designed for a 1/4 scale model sector magnet of the SSC. The
design parameters of the coil are listed in Table 1. Direct immersion cooling method in a liquid
helium bath was used.
cryostat.

Figures 1 and 2, respectively, show outline and cross sectional views of the

It is designed so as to have the same dimensions as normal copper coils already usedin the model magnet.

A welded helium can is completely enclosed by a copper can wrapped
Table 1

Specification of superconducting coil.

Max. excitation
Conductor
Copper ratio
Operating max. current

32500 AT
NbTi , 1.6 X 2.5 mm
4 : 1

650 A

Critical current

1000 A at 5T

Number of turns
Max. current density

50
162.5 A/mm 2

Weight30 kg/coil
76

806

Support rod

Superinsulati on
Helium can------ Superconducti ng coil
' - - --

Fig. 1.

Outline of the cryostat.

Fig. 2.

----''---- Vacuum vessel

The cross sectionalview of the cryostat.

202

with 16 layers of super insulation to shield from heat radiation. This copper shield is housed
in a vacuum chamber cryostat made of stainless steel. The coil is suspended by four FRP rodsof 10 mm diameter.
The strength of magnetic leakage flux through the coil was estimated from the calculations of
the magnetic induction of model magnet by using program TRIM.l) The stabilizatio n designof the coil was carried out with the aid of the results of calculations. The maximum magnetic
induction on the coil surface was estimated to be about 4 kG.

Fig. 3.

Fully assembled

supercondu cting coil.
Test of the coil was made by applying a current without mounting it in the model magent.
Figure 3 shows the fully assembled supercondu cting coil. The cryostat of the coil is connectedwith a liquid He vessel to supply electric current and liquid He. The coil reached the designed
maximum current without any quench. The coil was cooled from room temperatur e to that ofliquid N 2 in 40 min. It took another 110 min to cool the coil down to liquid He temperatur e.
The total thermal loss ammounted to 4.7 W in operation for supplying a current of 650 A.
This result agreed with the estimating value. Several strain gauges were set on the coil bobbin inorder to measure the deformatio n of the coil due to magnetmec hanical force. But they did notfunction well.
Recently the design of the SSC has been modified so that ions are accelerated by means ofharmonic number 9 in place of 8. The modificatio n allows to use a wide space in the central
2
region of the SSC and to save the power consumptio n. ) As a result of this choice, the total
power consumed in the main coils of the sector magnets has been reduced by more than
one-half, from 960 kW to 450 kW. It is estimated that the initial and operating cost of
supercondu cting coil system exceeds that of normal copper coil system. Hence the meritwhich might have been given by introductio n of supercondu cting coil has been lost. The
constructio n group of the sse decided to adopt normal copper coil.

References
1)
2)

J. S. Colonias and J. H. Porst: Magnet Design Application s of the Magnetosta tic Program
Called TRIM, UCRL-1638 2 (1965).
H. Kamitsubo: Proc. of 3rd Symp. on Accelerator Science and Technology , at RCNP,
Osaka, Aug., p.325 (1980).

203

11-16.

Present Status of Radiation Shielding for the
Riken SSC Facility

S. Fujita, S. Yamaji, and T. Shikata

The Riken SSC will accelerate protons in the energy range upto 200 MeV, deuterons, alpha particles, carbon,
nitrogen, and neon ions upto 135 MeV/A, and heavier ions in lower energy region.
will be 1 J.1A.

The maximum beam current

In considering the problem of radiation protection, we decided to take the value of 100 mrem/W (2 mrem/hwhen one week is considered as 48 h) for the allowed radiation levels in the radiation control area, 30 mrem/W(0.6 mrem/h when one week is considered as 48 h) on the outer surfaces of the shielding walls, and 10 mrem/W(0.06 mrem/h when one week is considered as 168 h) at the boundary with inhabitants.

In addition to these values, we adopted internally a value of 5 mrem/Y at the boundary with inhabitants as
the design goal of the shielding calculation .

This means that we will design the shielding of the cyclotron andexperimental facilities to reduce radiations from them at the boundary below this value.

Table 1.

Calculated number of neutrons per steradian and per 20 MeV energy range producedby the interaction of 1000 ions of a) 200 MeV p with 27 A1 and of b) 135 MeV/A
12

C with 56 Fe, respectively.

Table 1 (a) was obtained from Fig. 1 of Ref. 2.

Table 1 (b) was approximately obtained by increasing the energy of emitted neutronsin Table 7 of Ref. 3 by the amount of 35 MeV, as the incident energy of 12 C
accelerated in the Riken sse is by 3 5 Mev IA higher than that given in Ref. 3.
(a)0°-20°

20°-40°

42.7

24.0

16.8
13.4
12.0
9.5
8.01
7.55
7.02
5.59
1.67

10.0
7.4
6.0
5.4
4.6
3.5
2.2
0.8
0.1

~

0° - 20°20°-40°35- 5555- 7575- 9595 - 115
115-135
135-155
155 - 175

30
122
100
24
5.8
1.6
0.52

33
49
27
7.4
1.7
0.6
0.2

20- 4040- 6060- 8080- 100
100 - 120
120 - 140
140 - 160
160- 180180-200

40°-60°60° - 120°120°- 180°

5.4
2.6
0.88
0.16
0.013
0.0
0.0
0.0
0.0
0.0

1.34
0.30
0.04
0.0
0.0
0.0
0.0
0.0
0.0
0.0

40° - 60°60°- 120°120°- 180°

29.4
22
9.2
2.5
0.3
0.14
0.04

23.4

25.2
18.1
9.4
1.4
1.1
0.73
0.04

26.0
8.0
5.4
3.6
2.3
1.24
0.52
0.18
0.032
0.0034(b)Energy(MeV) ~

11

5
1.2
0.24
0.06
0.01

204

Conversion factors from particle flux density to dose rate for neutrons.

Table 2.

Neutron energy

Conversion factor(n/cm sec/mrem/h)(MeV)(n/cm 2 sec/mrem/h)

2.5 X 10- 8

265

3 X 10°

7.0

7

242

5 X 10°

6.8

222

1 X 10 1

6.8

231

2 X 10

1

6.5

239

5 X 10

1

6.1

272

1 X 10 2

Conversion factor

Neutron energy

2

(MeV)

1 X 10-i X 10- 6
1 X 10-

1

5

X 10- 4

1 X 10- 3

1 X 10-

2

5.55

2

5.10

283

2 X 101 x 1o- 1

48

5 X 10 2

3.60

5 X 10- 1

14

1 X 10 3

2.25

1 X 10°

8.5

2 X 10 3

1.55

2 X 10°7.0
1

Since the most penetrating component of radiation is high-energy neutrons, ) our effort is concentrated on theshielding against neutrons.
Among the neutrons ejected by nuclear reaction between energetic ion beams and targets , the number ofhigh energy neutrons will differ by no more than a factor of two for various combinations of target materials
and incident particles with the same energy per nucleon , after Refs. 2, 3, and 4. So we considered following two
typical reactions as sources of neutrons to estimate the thickness of the shielding wall: 1) proton beams incident
on a thick aluminum target and 2) carbon beams incident on a thick iron target. Spectra of neutrons which will5

be emitted in the above two cases are shown in Table 1_2), )There are two kind of radiations which have to be considered: the direct radiation coming through theshielding wall and the skyshine due to the backscattering of radiation from the atmosphere. In order to calculate
the radiation levels in the control area and on the outer surface of the shielding, the skyshine was neglected becauseof its smallness compared with the direct radiation in the region near the neutron source.
to the attenuation can be estimated by the relation

The direct radiation due(1)e x p (- fJ. x ) .

¢D =2Here ¢ 0 is the neutron flux density (n/cm ) at distance r from the source, ¢ 0 is the neutron flux density (n/sr) at the
1 6source, J1 is the linear absorption coefficient of ordinary concrete (cm- ), ) and xis the thickness of walls. In this7
calculation, factors for converting neutron flux density to dose equivalent shown in Table 2 ) was used. The
2
results obtained are shown in Fig. 1. Here, a larger value between the calculated values of r ·dose-rate for both cases(p on Aland Con Fe) was selected in each angular region. From these curves one can easily determine the shieldthicknesses in various directions with respect to the beam. For example, the design of a beam dump shield is shownin Fig. 2. The radiation level just outside the beam dump shield was taken to be 2 mrem/h.
The radiation level at the boundary with inhabitants was estimated only by the contribution from skyshine,
neglecting that of the direct radiation , because the latter decreases more rapidly than the former as the distance between
the source and the observing point increases. Also the fact that the building of the SSC is designed to be buried in the
ground reduces the contribution of the direct radiation.
8
For our calculation of the skyshine effect, we used the following empirical expression given by Thomas ) whichis to be used at distances larger than about 50 meters:¢ s_ { 1 - e xp ( _a_Q_L
4 nr~ ) } e x p (- ~ ) ( n / c m L · s ec )
A

for r

>

50m,

(2)

205

\

10

\

8

--- - P ( 200MeV )- AI
12
C (1 35MeV/ A)-

'

56

--

Fe

,\'

\ ~

\

~
E

'

'

\

\

v

\\\

Q)
<f)

0

0

~-fO~ 1 4~0

v

\

\\\

\ / ()= 120°- 180°\()= 40°- 60°/

\ I\

\

0 t6o'\ \\105 () I ~ 0 1"'1:-00 20°

()

\

' '

\

\

\

\ '\
\

1\

2

Fig. 1.

3

4

5

6

\ '\

7
8
ThicKness of concrete wall (m)910Fig. 2. The design of a beam dump shield of
iso-dose rate contours, where the shield material
is ordinary concrete. (p = 2.4 g/cm 3 )Dose rate multiplies by r 2 vs thickness ofconcrete wall.

-12

C ( 135MeV/ A)-

56

Fe ::

-

t\-850m
1 - - t\=267m
10m rem/ W ( 1W 168h)~~'5mrem / Y ( 1 Y

5 OOOh)!".. · ,I'-. !'-...

......
!'-... r-- .......

\'................

Q)
<f)

0

o 10 - 1~-.........

............._

w-2

I

"

""""

~

........

"........

........ .

.]IJ'J !-- ~........ ......

Ti·!'.. ~'--'r-~ckt?,ess orr--.;!--!--"!'-.... r-...

enc;0Ser--= r-I=

r--..1(}]........!'-....

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

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

-........._5rnf"""-. ................

0

100
200
300
400
Distance from neutr on source ( m)Fig. 3. Spatial distribution of neutron
skyshine. Values of 267 m and 850 m
for the attenuation length A. were adopted
as minimum and maximum values,
respectively.

where Q stands for neutron source strength in unit of n/sec, a and a stand for fitting parameters which reproduce theexperimental data, A. stands for attenuation length in air and r stands for the distance from the source. Following values
are taken for a, a , and A.:

a= 2.8 ,a= 56 m,A. = 267m or 850 m.
Equation (2) is considered to be the most reliable one at present, although we have not yet obtained satisfactory results
due to the complexity of the skyshine problem.

206

As the yield of neutron skyshine for the case of carbon was by a factor of about 10 larger than that for proton, theresult for carbon was chosen in our calculation. The result together with the radiation levels for design criterion isshown in Fig. 3. As there are several observed values for the attenuation length A., the calculation was performed fortwo extreme values of A.= 267 m and 850 m and the corresponding results are shown by solid and dashed curves,
respectively. Using this figure, the required roof thickness can be estimated to be more than 4 m, if the nearest
boundary with inhabitants is located at 100m from the sse facility.

References
1)
2)
3)
4)
5)
6)
7)
8)

R. G. Alsmiller: Nucl. Instr. and Meth., 72, 213 (1969).
H. A. Smith: IUCF Internal Rep., No. 74-6 (Radiation Shielding Note 1).
S. J . Lindenbaum: Ann. Rev. Nucl. Sci., ..!..!., 213 (1961 ).
T. Nakamura : INS-NUMA-5, p.321 (1977).
J. Drouet and A. Leleux: "Rapport de synthese des calculs effectues pour la determination des blindages del'accelerateur GANIL" , D. CEN-S/SPR/SRI/78-342 GRA-066JD/AI 5 mai (1978).
R. Wallace : Nucl. Instr. and Meth., 18 · 19, 405 (1962).
H. W. Patterson and R. H. Thomas: "Accelerator Health Physics", Academic Press, p.69 (1973).
H. W. Patterson and R. H. Thomas: ibid., p.442.

207

12. LIST OF PUBLICATIONS

1.

Machine development and accelerator physics
1) Y. Yano: "Design of Injection System for Separated Sector Cyclotron Proposed at theInstitute of Physical and Chemical Research (I)", Sci. Papers I.P.C.R., 74, 13 (1980).
2) N. Kishida, Y. Yano, and T. Wada: "Design of Beam Transport System for the IPCR
SSC(I)" , Sci. Papers I.P.C.R., 74 , 105 (1980).
3) A. Goto, Y. Yano, T. Wada, and N. Nakanishi: "Design of Injection System for the
IPCR SSC (II)", Sci. Papers I.P.C.R., 74 , 124 (1980).

2.

Nuclear physics and nuclear instrumentation
1) M. Yanokura, I. Kohno, H. Nakahara, and K. Yanakoshi: "Heavy Ion Identification
System by Using a Gas Proportional Telescope" , Oyo Buturi , 49, 1095 (1980).
2) H. Ohnuma, T. Kubo, N. Kishida, T. Hasegawa, N. Ueda, T. Fujisawa, T. Wada, K. lwatani,
and T. Suehiro: "Vector Analyzing Power and Polarization Measurements for the
116 Sn(d, p ) 117
Sn Reaction and Deuteron D-State Effects", Phys. Lett., 97B, 192 (1980).
3) T. Wada, H. Kumagai, and T. Inamura: "Data Processing System for IPCR Linac",
Genshikaku Kenkyu, 25, No.2 ( 1980).
4) H. Kamitsubo: "Heavy Ion Reaction - Quasi Elastic and Deep Inelastic Collision",
Butsuri, 35, 981 ( 1980).

3.

Atomic and solid-state physics
1) M. Uda, K. Maeda, H. Endo, Y. Sasa, and M. Kobayashi: "Chemical Effect on
Ion-Induced L X-Ray Spectra of Transition Elements", Proc. Intern. Conf. X-Ray
Processes and Inner-Shell Ionization, Plenum Pub. Co., New York (1980).
2) Y. Awaya: "Systematics of Multiple Ionization in Heavy Ion Collisions", Electronic andAtomic Collisions, North-Holland Pub. Co., Amsterdam, p.325 (1980).
3) T. Okada and H. Sekizawa: "Mossbauer Study of 119 Sn in Chromium and ManganeseDioxides", J. Magn. Ma gn. Mat., 15-18, 649 (1980).
4) Y. Awaya, T. Katou, H. Kumagai , T. Tonuma, Y. Tendow, K. Izumo, A. Hashizume,
T. Takahashi, and T. Hamada: "Ratio of Single K-Shell Ionization Cross Section to1

Double K- Shell Ionization Cross Section in Heavy-Ion-Atom Collision", Phys. Lett., 75A,.
478 (1980).
5) H. Endo, M. Uda, and K. Maeda: "Influence of the Chemical Bond on the Intensities
ofF Kcx X-Ray Satellites Produced by Electron and Photon Impacts", Phys. Rev. A, 22,1436 (1980).
6) T. Tonuma, Y. Awaya, T. Kambara, H. Kumagai, M. Kase, A. Yagishita, and I. Kohno:"Krypton K{3/Kcx Intensity Ratios for 6 MeV /amu Ion Bombardment", Atomic
Collision Research in Japan (Progr. Rep.}, _2_, 86 (1980).
7) T. Kambara, Y. Awaya, A. Hitachi, M. Kase, I. Kohno , and T. Tonuma: "X-Rays from110 MeV Ne Ions Passing through Gaseous Targets", Atomic Collision Research in Japan,(Pro gr. Rep.), 6, 91 (1980).
8) H. Fukushima and N. Shiotani: "Positron Annihilation in Amorphous Alloys", Solid
State Phys._, 12_, 4 7 5 ( 1980).

2089) K. Maeda and M. Uda: "Application of Anomalous Oxygen Kcx 532 eV Peak for theDetermination of Metal Oxide Thickness" , Spectrochimica Acta, 35B, 561 (1980).
4.

Radiochemistry, radiation chemistry and radiation biology
119
Sn, 119 Sb , and 119 mTe1) F. Ambe and S. Ambe: "Mossbauer Emission Studies of DefectAtoms after Nuclear Decays and Reactions in SnSb, SnTe, and Sb 2Te 3 ", J. Che·m . Phys.,
73 , 2029 (1980).
2) F. Yatagai, T. Takahashi, and A. Matsuyama: "Effect of Heavy Ions on Bacterial
Spores", Int. J. Radiat. Bioi., 37, 558 (1980).
3) T. Takahashi, F. Yatagai, and A. Matsuyama: "Possible Long Range Effects in theInactivation of ~acterial Cells by Heavy Ions", Sci. Papers I.P.C.R. , 74 , 51 (1980).

5.

Heavy ion linear accelerator1) M. Kase, Y. Miyazawa, M. Hemmi, and M. Odera: "Initial Performance of the Heavy-Ion
Source for the Riken Linac, RILAC", Proc. 4th Symp. on Ion Sources and Ion
Application Technology, (Ed. T. Takagi), In st. Electrical Eng. Japan, p.257 (1980).
2) M. Odera: "Riken Variable Frequency Linac, RILAC", Proc. 3rd Symp. on Accelerator
Science and Technology, (Ed. M. Kondo), RCNP, Osaka Univ., p.23 (1980).
3) N. Kishida, Y. Yano, T. Wada , S. Motonaga , and H. Kamitsubo: "Design of the BeamTransport System for the IPCR SSC" , Proc. 3rd Symp. on Accelerator Science andTechnology, (Ed. M. Kondo), RCNP , Osaka Univ., p.41 (1980).
4) T. Kambara , M. Odera, and S. Takeda: "Control System of Riken Linac", Proc. 3rd
Symp. on Accelerator Science and Technology, (Ed. M. Kondo), RCNP, Osaka Univ ,p.l31 (1980).
5) M. Yanokura, I. Yokoyama, I. Takeshita, and M. Odera: "Beam Buncher and Chopperof the Riken Variable Frequency Linac, RILAC", Proc. 3rd Symp. on Accelerator
Science and Technology, (Ed. M. Kondo), RCNP, Osaka Univ. , p.l47 (1980).
6) M. Kase, I. Yokoyama, M. Hemmi, M. Yanokura, J. Schimizu , and M. Odera: "BeamDiagnostic Probes of the RILAC", Proc. 3rd Symp. on Accelerator Science and Technology,(Ed. M. Kondo) , RCNP, Osaka Univ., p.l51 (1980).
7) M. Hemmi, Y. Miyazawa, M. Kase, T. Inoue, and M. Odera: "Injector Terminal of the
RILAC", Pro c. 3rd Symp. on Accelerator Science and Technology, (Ed. M. Kondo) ,RCNP, Osaka Univ., p.245 ( 1980).
8) N. Yasumitu, T. Minakuchi , E. Toyota , and N. Kishida: "Design and Operational
Performance of Superconducting Coil for SSC Sector Magnet", Proc. 3rd Symp. on
Accelerator Science and Technology, (Ed. M. Kondo) , RCNP, Osaka Univ ., p.319 (1980).
9) M. Odera: "Status of Riken Variable Frequency Heavy Ion Linac, RILAC", Proc. 5th
Linac Technology Conf., (Ed. T. Tomimasu), (in Japanese), Electro-TechnicalLaboratory, Tsukuba, p.l (1980).

209(Papers Presented at Meetings)
1.

Machine development and accelerator physics
1) Y. Yano, H. Takebe, T. Wada, Y. Obana, S. Motonaga, and H. Kamitsubo: "Model Testof the Injection Bending Magnet of the IPCR SSC", Ann. Meeting of Phys. Soc. Japan,
Tokyo, Mar. ( 1980).
2) N. Nakanishi, N. lida, S. Motonaga, and H. Kamitsubo: "Orbit Calculation III in IPCR
SSC", Ann. Meeting of Phys. Soc. Japan, Tokyo, May (1980).
3) I. Kohno and K. Ikegami: "Multiply-charged Metal Ion Source for Cyclotron", 4thSymp. on Ion Sources and Ion Application Technology , Tokyo, June (1980).
4) I. Kohno, K. Ikegami, and T. Kageyama: "Heavy Ion Source for the IPCR Cyclotron",
3rd Symp. on Accelerator Science and Technology , Osaka, Aug. ( 1980).
5) Y. Yano , A. Goto, T. Wada, H. Takebe, Y. Obana, N. Kishida, S. Motonaga, and
H. Kamitsubo: "Design of Injection System for the IPCR SSC (I)", 3rd Symp. on
Accelerator Science and Technology, Osaka, Aug. (1980).
6) A. Goto, Y. Yano, T. Wada, H. Takebe, Y. Obana, N. Kishida, N. Nakanishi, S. Motonaga,
and H. Kamitsubo: "Design of Injection System for the IPCR SSC (II)" , 3rd Symp.
on Accelerator Science and Technology, Osaka, Aug. (1980).
7) M. Hara, K. Ogiwara, and T. Fujisawa: "RF Cavity for IPCR SSC" , 3rd Symp. on
Accelerator Science and Technology, Osaka , Aug. (1980).
8) N. Nakanishi, K. Yamashita , T. Wada , A. Goto, Y. Yano, S. Motonaga, and H. Kamitsubo:"Orbit Calculations for the IPCR SSC", 3rd Symp. on Accelerator Science and Technology ,Osaka, Aug. ( 1980).
9) I. Kohno: "Ion Source for Accelerator", Symp. on Ion Beam Engineering, Wako, Dec.
( 1980).

2.

Nuclear physics and nuclear instrumentation
1) A. Hashizume , T. Katou, Y. Gono, and Y. Tendow: "The Ground State Band in 158 Yb
Excited by the 142 Nd( 20 Ne, 4n) Reaction", Ann. Meeting of Phys. Soc. Japan, Tokyo,
Mar. (1980).
2) H. Utsunomiya , T. Nomura , M. Ishihara , Y. Gono , T. Sugitate, and K. Ieki: "Relaxation
Phenomenon of Angular Momentum in Heavy-Ion Reactions 2", Ann. Meeting of Phys.
Soc. Japan, Tokyo, Mar. (1980).
3) K. Ieki, M. Ishihara, T. Nomura , Y. Gono, H. Utsunomiya, and T. Sugitate: "Spin
Alignment of Heavy Fragment in Heavy Ion Reactions", Ann. Meeting of Phys . Soc.
Japan, Tokyo, Mar. (1980).
4) T. Sugitate, T. Nomura, M. Ishihara, H. Utsunomiya, Y. Gono, and K. Ieki: "Polarization
Phenomena of Protons in Heavy-Ion Reactions", Ann. Meeting of Phys. Soc. Japan,
Tokyo, Mar. ( 1980).
5) S. Yamaji , A. Iwamoto , K. Harada, and S. Yoshida: "Microscopic Calculation ofFrictional Tensors for Ar + Au and Cu + Au", Ann. Meeting of Phys. Soc. Japan,
Tokyo , Apr. ( 1980).
6) T. Fujisawa , S. Motonaga, N. Ueda, S. Yamada , T. Hasegawa , and M. Sekiguchi:"Performance of the IPCR Polarized Proton and Deuteron Source" , 5th Intern. Symp. on

210

Polarization Phenomena in Nucl. Phys., Santa Fe, (New Mexico), Aug. (1980).
7) T. Fujisawa, N. Kishida, K. Kudo, T. Hasegawa, M. Sekiguchi, N. Ueda, M. Yasue,
Y. Wakuta, and A. Nagao: "Spin Flip Asymmetry in the Inelastic Scattering of Protons
on 12 C at Energies from 22.0 to 29.0 MeV", 5th Intern. Symp. on Polarization Phenomena
in Nucl. Phys., Santa Fe, (New Mexico), Aug. ( 1980).
8) N. Ueda, S. Yamada, T. Hasegawa, M. Sekiguchi, T. Fujisawa, and S. Motonaga:"Acceleration of the Polarized Proton and Deuteron at the INS SF Cyclotron", 5thIntern. Symp. on Polarization Phenomena in Nucl. Phys., Santa Fe, (New Mexico),Aug. (I 980).
9) T. Sugitate, T. Nomura, M. Ishihara, Y. Gono, H. Utsunomiya, K. Ieki, and S. Kohmoto:"Polarization of Preequilibrium Proton Emission in the 93 Nb + 14 N Reaction", Intern.
Conf. on Nucl. Phys., Berkeley, Aug. (1980).
10) S. Yamaji, A. Iwamoto, K. Harada, and S. Yoshida: "Microscopic Calculation ofFrictional Tensors Including Mass Asymmetry", Intern. Con f. on Nucl. Phys., Berkeley,Aug. ( 1980).
11) T. Nomura: "Evidence for the Hot-Spot Formation in Heavy-Ion Fusion-Like Reactions",
Intern. Conf. on Nucl. Phys., Berkeley, Aug. (1980).
12) S. Kohmoto, M. Ishihara, H. Kamitsubo, T. Nomura, Y. Gono, H. Utsunomiya, T. Sugitate,
and K. Ieki: "Lifetime Measurement of a Heavy-Ion Preequilibrium System via a-a
Correlation", Intern. Con f. on Nucl. Phys., Berkeley, Aug. (1980).
13) Y. Nagame, M. Watanabe, H. Kudo, H. Muramatsu, H. Nakahara, and I. Kohno: "HeavyIon Reactions between 115 MeV 14 N and 62 Ni", Discussion Meeting on Radiochem.,
Hirosaki, Oct. (1980).
14) Y. Nagame, H. Kudo, H. Nakahara, M. Yanokura, and I. Kohno: "Heavy-Ion Reactions
between 20 Ne and 5° Cr (I)", Discussion Meeting on Radiochem., Hirosaki, Oct. (1980).
15) H. Kudo , Y. Nagame, H. Muramatsu, H. Nakahara, K. Miyano, and I. Kohno: "Studyon the Proton-Induced Fission of 232 Th (III), Mass Yield", Discussion Meeting onRadiochem., Hirosaki, Oct. (1980).
16) H. Kudo, Y. Nagame, H. Muramatsu, H. Nakahara, K. Miyano, and I. Kohno: "Study on
the Proton-Induced Fission of 232 Th (IV), Angular Distribution", Discussion Meetingon Radiochem., Hirosaki, Oct. (1980).
17) H. Utsunomiya, T. Nomura, M. Ishihara, T. Sugitate, S. Kohmoto, and K. Ieki:"Measurement of Spin Alignment Following Preequilibrium a-Particle Emission in
Heavy-Ion Reactions", Ann. Meeting of Phys. Soc. Japan, Fukushima~ Oct. ( 1980).
18) S. Kohmoto, M. Ishihara, H. Kamitsubo, T. Nomura, Y. Gono, H. Utsunomiya, T.
Sugitate,. and K. Ieki: "Final State Interaction between Two Particles Emitted from
Heavy Ion Reactions", Ann. Meeting of Phys. Soc. Japan, Fukushima, Oct. ( 1980).
19) Y. Nagame, I. Kohno, M. Yanokura, H. Kudo, and H. Nakahara: "Heavy Particle
Emissions in Reactions between 20 Ne and 5°Cr", Autumn Divisional Meeting of Phys. Soc.
Japan, Fukushima, Oct. (1980).
20) T. Sugitate, T. Nomura, M. Ishihara, H. Utsunomiya, K. Ieki, and S. Kohmoto:"Polarization Phenomena of Protons in Heavy-Ion Reactions II", Autumn Divisional
Meeting of Phys. Soc. Japan, Fukushima, Oct. (1980).
21) A. Iwamoto, S. Yamaji, K. Harada, and S. Yoshida: "Friction Tensors for Ar + Au",

211

Autumn Divisional Meeting of Phys. Soc. Japan, Fukushima, Oct. (1980).
22) H. Kudo, Y. Nagame, H. Nakahara, K. Miyano, and I. Kohno: "Angular Distributionsof Fission Fragments in the Proton-Induce d Fission of 232 Th", Autumn Divisional
Meeting of Phys. Soc. Japan, Fukushima, Oct. ( 1980).
3.

Atomic and solid-state physics
1) Y. Awaya: "Present Studies and Plannings on Atomic Collision in the IPCR", Symp. on
Atomic Collisions by Using Accelerators, Tokyo, Jan. (1980).
2) Y. Awaya: "Comments on Multiple Inner-Shell Ionization", Symp. on Atomic Collisions
in Solids, Tokyo, Jan. (1980).
3) T. Okada, H. Sekizawa, F. Am be, and S. Am be: "Mossbauer Study of 119 Sb in a-Fe 0 ",2 3Ann. Meeting of Phys. Scfc:··Japan, Tokyo, Mar. ( 1980).
4) M. Kamiya, A. Kuwako, M. Sebata, K. Ishii, S. Morita, Y. Awaya, and T. Tonuma:"K-Shell Ionization of Elements Ranging from Ca to Ni by 5, 6, and 7 MeV /amu
a-Particles and N 7 + Ions", Ann. Meeting of Phys. Soc. Japan, Tokyo, Mar. (1980).
5) N. Shiotani, T. Okada, N. Sakai, H. Sekizawa, and T. Nakamichi: "Compton Plofile
and Positron Annihilation in Nb-20 at. % Mo", Ann. Meeting of Phys. Soc. Japan,
Tokyo, Mar. ( 1980).
6) M. Hara and K. Mori: "Test of Position Sensitive Detector for Spectrometer II", Ann.
Meeting of Phys. Soc. Japan, Tokyo, Mar. ( 1980).
7) T. Tonuma, Y. Awaya, T. Kambara, H. Kumagai, and I. Kohno: "The K{3/Ka Intensity
Ratio of Kr X-Rays Induced by 6 MeV /amu Heavy Ions", Ann. Meeting of Phys. Soc.
Japan, Tokyo, Mar. (1980).
8) H. Shiraishi, H. Shinno, N. Yamamoto, N. Kainuma, R. Watanabe, H. Kamitsubo, I. Kohno,
and T. Shikata: "Effect of Aging on Helium Embrittlemen t of Precipitation-S trengthened
Fe-Ni-Cr Alloys", Ann. Meeting of the Atomic Energy Soc. Japan, Nagoya, Mar. (1980).
9) M. Hara and K. Mori: "Observation of VUV Spectra by Position Sensitive Detector",
Spring Meeting of Appl. Phys. Soc. Japan, Kofu, Apr. ( 1980).
10) M. Hara and K. Mori: "Multichannel Detection in Normal Incidence Vacuum Ultraviolet
Region", Vlth Intern. Conf. on Vacuum Ultraviolet Radiat. Phys., Charlottesville, June (1980).
11) T. Mizoguchi, N. Shiotani, U. Mizutani, T. Kudo, and S. Yamada: "Structure andPhysical Properties of a Simple Metal-Metal Amorphous Alloy Mg Zn ", 4th Inter.n . Con f.
70
30
on Liquid and Amorphous Metals, Grenoble, July (1980).
12) T. Tonuma, Y. Awaya, T. Kambara, H. Kumagai, M. Kase, A. Yagishita, and I. Kohno:"Kr K{3/Ka Intensity Ratios by 6 MeV /amu Ion Bombardment ", Symp. at the Soc.
for Atomic Collision Research, Tokyo, July (1980).
13) T. Tonuma, Y. Awaya, T. Kambara, H. Kumagai, M. Kase, A. Yagishita, and I. Kohno:"Krypton K{3/Ka X-Ray Intensity Ratio by Impact of 6 MeV/amu He, N, and Ne Ion
Bombardment ", Intern. Conf. on X-Ray Processes and Inner-Shell Ionization, Glasgow,
Aug. ( 1980).
14) M. Uda, K. Maeda, H. Endo, Y. Sasa, and M. Kobayashi: "Chemical Effect on Ion-Induced
L X-Ray Spectra of Transition Elements", Intern. Conf. on X-Ray Processes andInner-Shell Ionization, Glasgow, Aug. (1980).
15) N. Shiotani and T. Mizoguchi: "Positron State in Amorphous Mg Zn ", Ann. Meeting70
30
of Phys. Soc. Japan, Fukui, Oct. (1980).

21216) T. Okada, H. Sekizawa, F. Ambe, and S. Ambe: "Mossbauer Study of 119 Sb in Cr 0 ",2 3
Autumn Divisional Meeting of Phys. Soc. Japan, Fukui, Oct. (1980).
17) T. Kambara, Y. Awaya, A. Hitachi, M. Kase, I. Kohno, and T. Tonuma: "X-Rays from
Collision of 110 MeV Ne Ions with Gas Targets", Autumn Divisional Meeting of Phys.
Soc. Japan, Fukui, Oct. (1980).
18) N. Yamamoto, N. Kainuma, H. Shiraishi, H. Yoshida, H. Kamitsubo, I. Kohno, andT. Shikata: "Aging Behaviour of Helium-Injected Precipitation-Stren gthened Fe-Ni-Cr
Alloys", Autumn Divisional Meeting of the Japan Institute of Metals, Fukuoka Oct.
(1980).
19) H. Shiraishi, H. Shinno, N. Yamamoto, H. Yoshida, H. Kamitsubo, I. Kohno, and T.
Shikata: "Change of Embrittlement Responce Due to Composition Modification andPre-injection Treatments in Helium-Injected Fe-Ni-Cr Alloys", Japan- US Seminar (E-1 0)
on Materials - Results of Irradiation Work and Exploration of Ferritic Status, Tokai-mura,
Oct. ( 1980).
20) Y. Awaya, K. Ando, T. Tonuma, A. Yagishita, A. Hitachi, and H. Kumagai:"Atomic-Collision Equipments of the Cyclotron and the Linear Accelerator of IPCR",
Symp. of Atomic Collisions by Using Accelerators, Wako, Dec. ( 1980).
21) T. Kambara, M. Kase, A. Hitachi, I. Kohno, T. Tonuma, and Y. Awaya: "X-Rays Following
Collisions of 110 MeV Ne Ions with Gaseous Targets", Symp. of Atomic Collisions
by Using Accelerators, Wako, Dec. (1980).
4.

Radiochemistry, radiation chemistry and radiation biology
1) T. Takahashi: "Analysis of Survival Curves and Track Structure of High LET Particles",Symp. on the Theor. Aspects of Survival Curves, Kuma tori, Jan. (I 980).
2) T. Nozaki and M. Iwamoto: "Some Fundamental Data Concerning the Formation of
Low Z Radionuclides", 3rd Intern Symp. Radiopharm. Chern., St. Louis, June (1980).
3) T. Nozaki, Y. Itoh, and A. Yusa: "Oxygen Depth Profile in Silicon and Its Change inHeat Treatment Measured by Charged Particle Activation Analysis", Discussion Meetingon Radiochem., Hirosaki, Oct. (1980).
4) T. Nozaki and M. Iwamoto: "Recoil Range of 18 F Formed by Various Reactions",
Discussion Meeting on Radiochem., Hirosaki, Oct. (1980).
5) F. Ambe, S. Ambe, T. Okada, and H. Sekizawa: 'd 19 Sn-Mossbauer Emission Spectra of
119 Sb Adsorbed
on Magnetic Oxides Surface", Discussion Meeting on Radiochem.,
Hirosaki, Oct. ( 1980).
6) Y. Itoh, T. Nozaki, and A. Yusa: "Measuring the Change of Oxygen Depth Profilein Silicon by Applying Heat Treatment", 41th Ann. Meeting of Japan Soc. Appl. Phys.,
Nagoya, Oct. ( 1980).
7) T. Takahashi, F. Yatagai, and A. Matsuyama: "Application of Katz's Theory to theAnalysis of Inactivation of Bacterial Cells - Possible Long Range Effect of Heavy Ions",
41th Ann. Meeting of Japan Soc. Appl. Phys., Nagoya, Oct. ( 1980).
8) I. Kaneko, T. Ohno, K. Suzuki, T. Taira, K. Nakano, and F. Yatagai: "Effects of
Nitrogen-Ion Beam Accelerated with IPCR Cyclotron on Human Diploid Fibroblast",
23rd Ann. Meeting of Japan Radiat. Res. Soc., Nagasaki, Oct. (1980).

213

5.

Heavy ion linear accelerator1) M. Kase, Y. Miyazawa, M. Hemmi, M. Yanokura, and M. Odera: "Initial Performanceof the Heavy Ion Source for the Riken Linac, RILAC", 4th Symp. on Ion Sources
and Ion Application Technology, Tokyo, June ( 1980).
2) M. Kase, I. Yokoyama, M. Hemmi, M. Yanokura, J. Schimizu, and M. Odera: "BeamDiagnostic Probes of the RILAC", 3rd Symp. on Accelerator Science and Technology,
Osaka, Aug. ( 1980).
3) M. Yanokura, I. Yokoyama, M. Hemmi, I. Takeshita, and M. Odera: "Beam Buncher
and Chopper of the Riken Variable Frequency Linac, RI LAC", 3rd Symp. on Accelerator
Science and Technology, Osaka, Aug. ( 1980).
4) T. Kambara, M. Odera, and S. Takeda: "Control System of Riken Linac", 3rd Symp. on
Accelerator Science and Technology, Osaka, Aug. ( 1980).
5) M. Hemmi, Y. Miyazawa, M. Kase, T. Inoue, and M. Odera : "Injector Terminal of the
RI LAC", 3rd Symp. on Accelerator Science and Technology, Osaka, Aug. (1980).
6) M. Odera : "Riken Variable Frequency Linac, RILAC", 3rd Symp. on Accelerator Scienceand Technology, Osaka, Aug. ( 1980) .
7) M. Odera: "Status of Riken Variable Frequency Heavy Ion Linac, RILAC", 5th Linac
Technology Conf., Tsukuba, Aug. ( 1980).
8) M. Odera: "Heavy Ion Linacs in Japan", Japan-China Accelerator Science and Technology
Symp., At ami, Sept. ( 1980).
9) M. Odera: "On the Accelerators for Research of Materials for Fission and Fusion
Reactors", Material Research Accelerator Work Shop at Ooarai Research Facility of
Tohoku Univ., Metal Laboratory, Ibaragi, Nov. (1980).

214

13. LIST OF OUTSIDE USERS AND THEIR THEMES(Jan. - Dec. 1980)
1) M. Shimada

Toshiba R & D Center"Cyclotron Irradiation for Study ofFast Breeder Reactor Material Embrittlement"
2) A. Hishinuma and T. Furuta

Japan Atomic Energy Research Inst.

"Helium Implantation Effect on Creep
Repture Properties of Modified 316 StainlessSteel for Fast Reactor Material"
3) K. Suganuma and S. Yajima*

Research Inst. for Iron, Steel and Other"Development of Ferritic Stainless Steel for

Metals, Tohoku Univ.

Atomic Reactor"*Irradiation Research Lab., in JMTR

4) M. Harada and H. Matsutani *"Study of Effect by Bombarding High Energy

Japan Trust Center for Electronic Parts*Electronic Parts Div., Sharp Co., Ltd.

Proton on a Solar Cell"
5) H. Nakahara, H. Kudo, and K. Muramatsu"Production of 112 Pd, 115 Cd, 119 msn, and
196 Au"6) Y. Homma

Faculty of Science, Tokyo Metropolitan
Univ.

Kyoritsu College of Pharmacy"Production of 52 Mn"
7) K. Yuita

National Inst. of Agricultural Sciences"Production of 77 Br"
8) H. Emori

Mitsubishi Metal Co., Ltd.

"Radiochemical Analysis of 16 0 in Ga AS"9) T. Watanabe"Production of 18 F"

Mitsubishi Aluminum Co., Ltd.

21510) M. Watanabe

Toshiba R & D Center"Radiochemical Analysis of 14 N in Si
Crystal"
11) T. Abe"Radiochemical Analysis of 14 N in Si
Crystal"Shinetsu Semiconductor Co., Ltd.

L

216

14. LIST OF SEMINARS(Apr. - Dec. 1980)
1) S. Kosugi, Tokyo Institute of Technology (Tokyo), 15 April"The Study of the Imaginary Part of the Optical Potential"
2) T. Udagawa, Univ. Texas (USA), 12 May"Break-up Processes in Heavy-Ion Collisions"
3) D. Youngblood, Texas A & M Univ. (USA), 20 May"EO Giant Resonances"4) M.N. Harakeh, KVI Groningen (Netherlands), 27 May"Giant Resonances of s, d-Shell Nuclei"5) H. Taketani, Tokyo Institute of Technology (Tokyo), 9 July
"The Study of the Fine Structures of Analogue Resonances Excited by (p, d) Reactions"6) M. Koike, INS (Tokyo), 22 July
"IT-on Production in Nuclear Collision"7) K. Shimizu, Univ. Ti.ibingen (BRD), 22 July
"IT-on Absorption and Two Nucleon Correlation"8) S. Nagamiya, LBL (USA), 25 July
"Recent Topics on Relativistic Heavy-Ion Collisions"9) R.C. Tribble, Texas A & M Univ. (USA), 28 July
"Mass Measurements of Nuclei Far from Stability and Exotic Spectroscopy"10) H. Yoshida, Tokyo Institute of Technology (Tokyo), 10 September"Contribution of Excitations of the Emitted Particles to the Nucleon Transfer in Heavy-Ion
Reactions"11) H. Yamada, Vanderbilt Univ. (USA), 18 September"Massive Transfer Reaction and the Applications to Studies of High Spin States"
12) S. Fukumoto, KEK (Tsukuba), 22 September"Applications of Accelerators"
13) P. Grand, BNL (USA), 9 October"Applications of Accelerators to Energy Problems"

21714) H. Tawara, Kyushu Univ. (Fukuoka), 14 October"Collision Phenomena of Highly Ionized High Energy Heavy-Ions and Its Applications"15) R.A. Jameson, LASL (USA), 17 October"Accelerator Developments in LASL"
16) K. Ogawa, INS (Tokyo), 22 October"Predicted High Spin Isomers in the A= 9 5 - 100 Nuclei"17) P. Radvanyi, LNS (France), 28 October"On Saturn II"18) M. Muraoka, INS (Tokyo), 18 November"Mechanism of High Energy Heavy-Ion Collision and Energy Spectra of Low Energy Pion"
19) H. Adachi and K. Taniguchi, Osaka Electro-Communication Univ. (Osaka), 25 November"Analyses of X-Ray Spectra Using the DV Xa-Methods"20) M. Ichimura, Univ. of Tokyo (Tokyo), 26 November"Alpha Spectra from the 12 Cci 6 o, a) Reaction"21) S. Hanashima, JAERI (Tokai), 1 December"Computer Control System of Tandem Van de Graaff at J AERI"
22) K. Yagi, Univ. of Tsukuba (Tsukuba), 3 December"Studies of Nuclear Reaction Mechanism Using the Polarized Beam"
23) H. Sasaki, KEK (Tsukuba), 9 December"Applications of 500 MeV Proton Beam from the Booster at KEK"
24) G. Igo, UCLA (USA), 22 December°"Third Observable in Polarized Proton Scattering on 4 Ca at 500 MeV"
25) I. Hamamoto, Nordita (Copenhagen), 25 December"Properties of Rotating Nuclei and the Role of High - J Shell"

218

15.

LIST OF PERSONNEL

Members of the Board
DOTE Toshihiko ± -f.
KAMITSUBO Hiromichi
NOZAKI Tadashi~~(Chairman)

J:. if 7.i.

ll!f ~

:@

~

ll!f

EB

:@

-

J)J

ODERA Masatoshi

iE

Users Committee

HAMADA Tatsuji
iilJ
KOHNO Isao=

(Chairman)
HAMADA Tatsuji ~ EB :@
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SATO Kenichi 16:: Jfi ~ - (Dept . Phys., Tohoku College of Pharmacy)
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