RIKEN
Accelerator
Progress Report
vol.

16

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

RIKEN Accelerator Progress Report 11 (Q){6)tr))
January-December U71 (Q)./b

I~ it ~.Jift ~ jiJi

thelnsfifute of Physical and Chemical Research
Wako-shi, Sailama, 351 JAPANEditors
Y. GonoA. Hashizu m e

T. Inamura

H. Kamitsubo

M. Odera

N. Shi otani

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

This report or any part thereof may not be reproduced in any

form (including photostatic or microfilm form) without written permission fromthe publisher.

PREFACE

This is the sixteenth issue of the RIKEN Accelerator Progress Report and summarizes
research activities and technical developments carried out at the Institute of Physical and Chemical
Research (RIKEN) using accelerators during the period from January to December in 1982.
Nuclear science is one of the principal research activities at RIKEN and about one hundred
scientists from inside as well as outside of the institute take part in the collaborative studies which
cover the research fields of nuclear physics, atomic and solid state physics, nuclear and radiation
chemistry, material engineering and radiation biology. It should also be emphasized that theaccelerators at RIKEN are open for the trials and tests to the application of accelerators to theindustrial uses. In the past one year the cyclotron provided protons, deuterons and alpha particles
for these purposes.
In order to extend the research area in the nuclear science and to develop the research
activities using the accelerators at RIKEN a new separated sector cyclotron with k = 540 is underconstruction. We expect we can get the first beam in the middle of 1986.
We would like to acknowledge to Prof. K. Shinohara for his critical reading of the manuscripts
and valuable comments. We also thank to Mrs. H. Masamoto and H. Takada for their editorial
works.

H. Kamitsubo
Editor

CONTENTS
Page
PREFACEI.

INTRODUCTIONII.

OPERATION OF ACCELERATORS

III.

1.

1.

Cyclotron Operation22.

Operation Statistics of RILAC

5

3.

TANDETRON-Operation

8

RESEARCH ACTIVITIES
Nuclear Physics
1.

Excitation Functions for 14N-Induced Reactions on 62Ni

92.

Strongly Damped Components in the Reactions of 2~e + 92Mo
and 2~e + 1D<Mo Systems , ...................................... .

12

3.

High-lying Proton Strengths Observed in (12c, llB) Reactions ............ .

15

4.

Polarization Measurement for Continuous Protons Emitted in the'(a, p) and (14N, p) Reactions ..................................... .

18

Angular-Momentum Transfer and Alignment Following Preequilibrium
a-Particle Emission in 160_ and 2CNe-Induced Reactions ................ .

19

6.

Light-Particle Emission in 7Li-Induced Reactions ...................... .

22

7.

Momentum Transfer Light-Particle Emission Following
210 MeV 14N-Bombardment on 23Prh .............................. .

26

8.

Spin Polarization of Residual Nucleus in Heavy Ion Reaction ............ .

28

9.

Vector Analyzing Power Measurements for (d, p) and (p, d) Reactions
on Sn Isotopes and Deuteron D-state Effects ......................... .

31

Excitation Modes of the 'Y-band in 24Mg through the24Mg(p, Ii) Reaction ............................................ .

35

11.

Multiple Coulomb Excitation of 167Er

38

12.

Excited States in 157Yb and 158Yb .................................. .

41

13.

Analysis of Gamma-Ray Multiplicity Distributions for the
159r[be 4N, axn) Reaction at 115 MeV ' .............................. .

43

5.

10.

Page
14.

Level Scheme of 217Ra ................. .. ........................ .

15.

Level Schemes of 216, 218 Ra

16.

In-Beam a- and 'Y-Ray Study on 215Fr and 217 Ac

17.

Numerical Analysis of 1280 MeV 208Pb Reactions on
94Zr, llOpd, 148Sm, and 170Er Based on the Linear Response Theory

54

Effects of the Mass Fragmentation Potential on theMass Diffusion Phenomena ........................................

58

Exact Finite-range Coupled-channel Born Approximation
Calculations with Spin-orbit Interactions ............................ .

61

Effects of Two Particle-Two Hole Excitations on theMass Distributions in Ion-Ion Collisions

63

18.

19.

20.

2.

46
48

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

51

Atomic and Solid-State Physicsl.

Target Gas Pressure Dependence of REC X-Rays from
Ne-Ion Bombardment

66

Target Gas Pressure Dependence of K-X Rays from110 MeV Ne Ions .................... . ............... . ..........

69

High Resolution Measurements of K X-Rays from
Argon Ions Impinging on Foils ...................... . ..............

72

Argon L-MM Auger Spectra in Arn+ + Ar Collisions (1)Identification of Auger Lines'75

Argon L-MM Auger Spectra in Arn+ + Ar Collisions (II)Energy Dependence of the Auger Spectra ..........................

77

Argon L-MM Auger Spectra in Arn+ + Ar Collisions (III)Structure of Argon L-MM Auger Spectra in 21 MeV Ar4+
Impact on Ar .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

79

7.

Angular Distribution of Sn LX-Rays ............................... .

82

8.

Production of Highly Charged Ions by Heavy-Ion
Bombardment of Rare-Gas Targets ..................................

85

Mechanical Design of Apparatus to Measure Secondary Ions ............. .

87

2.

3.

4.

5.

6.

9.

Page
10.

Scan Controller for Secondary Ion Experiment ........................

88

11.

Analysis of F K~-Emission Satellite Spectra from
Fluorine Compounds by the DV-X~ Method ..........................

89

Determination of Electron Contact Densities for Outermost
Electrons in Tin Compounds .......................................

91

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

94

12.

13.

96

Supertransferred Hyperfine Magnetic Field at
119Sn4+(~119Sb5+) on Cr 0 Surfaces .................................
2 3

98

Emission Mossbauer Studies of Dilute 119Sb Ions
Adsorbed on Ferrimagnetic Spinel Oxide Surfaces

101

Perturbed Angular Correlation of 'Y-Rays Emitted froml11Cd (~111In) on ~-Fe203' Cr 20 3, and a-A1 20 3 Surfaces

103

Dependence of Secondary Electron Emission Coefficientson Metal Targets under Bombardment with Bare Projectiles

105

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

108

20.

Amorphization of Diamond Surface Layer by Zn-implantation ............

109

21.

Pulsed Laser Annealing of Cd-implanted GaP ..........................

111

22.

Radiation Damages in Amorphous Alloys Irradiated with
C4+ and N 4+ Ions ............................................... .

113

Positron Angular Correlation Measurements on Oxygen Implanted
Molybdenum Containing Voids .....................................

114

Effect of an Injected Helium Layer near Surface on the Tensile
Properties of Fe-Ni-Cr Alloys ......................................

115

Effects of Fast Neutron Irradiation on Insulating Materials

118

15.

16.

17.

18.

19.

23.

24.

25.
3.

°

Effects of Chemical Bond on
K~ Spectra from Multiply
Ionized States ..................................................

14.

Radiochemistry and Nuclear Chemistry

Page

1.

Radioisotope Production and Labelled Compound Synthesis

120

2.

Charged Particle Activation Analysis of Semiconductor Materials

122

3.

Rutherford Forward Scattering Applied to the Study ofHydrogen in Amorphous Silicon for Solar Cell ........................

125

Separation of 119Sb(V), 119mTe(lV) and Sn(lV) by
Adsorption on Activated Carbon

128

5.

Mossbauer Emission Study of Defect 119Sn Atoms in Solids

130

6.

Research Project on Coulomb-Excitation Mossbauer Spectroscopy
Using Heavy Ions Accelerated by RILAC .............................

132

4.

4.

Radiation Chemistry and Radiation Biology

1.

2.

3.

4.

5.

5.

134

Application of Thermoluminescence Dosimeter for Dose
Measurement of High-LET Radiation ................................

137

Track Structure Theories and Inactivation Cross Sectionsof Bacterial Spores for Heavy Ions ...................................

139

Mutagenesis of Chinese Hamster V79 Cells by Nitrogen
Ion Beam .....................................................

142

Recovery from Potentially Lethal Damage of Human Cultured
Cells after Irradiation of Nitrogen Ion Beams .........................

144

Miscellaneous

1.
IV.

Spectroscopic Studies on the Electronic Excited States Formed
at High Density in Heavy-Ion Track . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Quantitative Trace Analysis by Particle Induced X-Ray Emission .......... 145

ACCELERATOR DEVELOPMENT
1.

Beam Attenuation Method Using Charge Transfer
Reactions ................. . .................................... 147

2.

Design of Axial Extraction PIG-Source

3.

ECR Ion Source

4.

Identification Method of Ions in the Beamfrom the RILAC Injector .........................................

.............................. 149................................................ 153

155

Page
5.

Bunch Signal Sensitization by Use of Secondary Electron
Emission ...................................................... 158

6.

Bunch Phase Monitor

7.

Linac Energy Tuning by Phase Control

8.

Suppression of Secondary Electron from Beam Stopper

9.

Status of RILAC RF System

10.

Investigation of Frequency Characteristics of the Screen
Grid Bypass Capacitor at the Final Stage of RF Power
Amplifier for RILAC ............................................. 169

11.

Basic Study on the RF High Power Amplifier for RIKEN SSC
Study of the Screen Bypass Capacitor for the Final Stage

171

Grid Tuning Circuit of A Type for the RF Power Amplifier for
RIKEN SSC ....................................................

173

13.

Control System of the Linac

176

14.

On a Possible Medium-~ RFQ Structure

178

15.

Present Status of the RIKEN SSC Project

181

16.

Construction of the Sector Magnets for the RIKEN SSC................

17.

Measurement of the Magnetic Fields of the RIKEN SSC................ 186

18.

Magnetic Field Measuring System for the RIKEN SSC
Sector Magnet .................................................. 188

19.

Structural Analysis of Sector Magnet by Finite Element Method

20.

Measurement of the Trim Coil Fields and Determination ofTrim Coils Power Supplies for the RIKEN SSC ........................ 197

21.

Beam Extraction System for the RIKEN SSC (II)Design Calculation of Magnetic Deflection Channel ................... 201

22.

Vacuum System of the SSC ........................................ 205

23.

Test of Model Pneumatic Expansion Seal ............................. 207

12.

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

160
162
164

...................................... 166......................................

183.......... 193

Page
Preliminary Experiment on the Surface Cleaning of
the Vacuum Chamber for the RIKEN SSC ...........................

210

Preliminary Experiment on Discharge Cleaning of a
Sector Magnet Vacuum Chamber for the SSC .........................

212

26.

Beam Diagnostic System for the RIKEN SSC ..........................

215

27.

Model Test of 1/5 Scale Movable Box Type RF Resonator
for the RIKEN SSC .............................................

217

28.

Effect of a Resonance on the Beam in the RIKEN SSC

219

29.

SSC Beam Handling System

30

Biological and Physical Irradiation Beam Channel for the
RIKEN SSC ................................................... 224

31.

Calculation of RF Electromagnetic Field by Finite Element
Method (II). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 227

32.

Status Report of the Prototype Baby Cyclotron

24.

25.

V.

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

......................... . ............. 222....................... 230

RADIATION MONITORINGl.

Routine Monitoring of the Cyclotron

2.

Leakage-Radiation Measurement at the Underground Passageof the Cyclotron Building ............................ . ............ 235

3.

Leakage X-Ray Measurement on T ANDETRON

4.

Radiation Levels Due to Neutrons from the Cyclotron
outside the Cyclotron Building ....................................

5.

233

....................... 237

239

Radiation Shielding for the RIKEN SSC Facility ....................... 243. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..

247

VI.

LIST OF PUBLICATIONSVII.

LIST OF OUTSIDE USERS AND THEIR THEMESVIII.

LIST OF SEMINARS

259

IX.

LIST OF PERSONNEL

261

AUTHOR INDEX.......................... 257

I.

INTRODUCTION

H. Kamitsubo

Since the collaborative research works started in 1967 using the 160 cm cyclotron at thisinstitute, the experimental studies of nuclear and atomic physics, solid state physics, nuclear andradiation chemistry, material engineering and radiation biology as well as the developments of the
instrumentation have been carried out. The main facilities now devoted for these research works
are the 160 cm cyclotron, the variable-frequency heavy-ion linac (RILAC) and the tandem van deGraaf accelerator (TANDETRON).
During the past one year the cyclotron was in good condition as before and 13C and 180 ionswere newly added to the ion group which can be provided steadily for the users. The RILAC has
been in steady operation in this period and ions of gaseous elements as well as metalic ones suchas alminum and nickel were used for studies in various research fields. The T ANDETRON was also
in steady op~ration and ions of helium and boron were mainly used for the studies of solid statephysics and chemical analysis.
A majority of research works have been carried out with heavy ions. In the field of nuclear
physics, studies of strongly damped components in heavy ion reactions, spin-polar.ization of residual
nuclei in heavy-ion collisions and in beam 0'- and 'Y-ray spectroscopy on actinide nuclei .have been
continued. X-rays, Auger electrons and recoil ions were measured in atomic collisions to get the
information on the spectroscopy of highly ionized atoms as well as on the collision mechanism.
Activation analysis of impurity oxygen has been continued to get the calibration curve for
infra-red spectrophotometry of oxygen in semiconductors. Resonance rreaction of lIB + P andforward-angle Rutherford scattering of argon were applied to measure the hydrogen distribution in
the amorphous silicon and other materials.
Measurements of perturbed angular cerrelation and Mossbauer effect were applied to study thesolid state physics and chemistry. This technique will be developed to the on-beam measurements.
Spectroscopic study on the excitation of noble gas atoms at the primary stage of the collision was
continued. Application of the cyclotron to the industrial and engineering problems has beendeveloped.
Construction of the separated sector cyclotron is in progress. During the past one year, twoamong four sector magnets were finished at the factory and their field distribution were measured.
Design of the remaining parts is now under way.

2

II . OPERATION OF ACCELERATORS

1.

Cyclotron Operation

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

The cyclotron was operated on the 24 h a day basis during the period from Oct. 23, 1981
to Oct. 22, 1982. The total operation time of 4365.3 h is 3 % (266.8 h) longer than that of
the last year. This increase in operation time is due to increased beam time shown in Table 1.

Table 1. Cyclotron operation.

Reading of time meter on Oct. 23,1981
Reading of time meter on Oct. 22, 1982
Difference
Percentage of 365 days
Schedule in this period
Beam time
Overhaul and installation work
Periodical inspection and repair
Vacation and holidays

Oscillator

Ion-source

Beam71424.4
76325.3
4900.975610.880614.2
5003.441327.2
45692.54365.3

55.9%

57.1%

49.8%

235 (days)
58
22
50

"Figure 1 shows the net beam time from the difference of reading of time meter over the past
10 years. The average of the net beam time is about 4400 h, and the net beam time indicatesconstant operation of the cyclotron in the last few years. Table 2 shows the beam time allotment
to various activities in this period. The scheduled beam time was decreased by 24 h comparedwith that of the last year: requirement for heavy ion beams decreased; its decrease was 359 h.
Table 3 shows the distribution of the scheduled beam time among particles accelerated.
Newly accelerated ions such as 13C4+ 180 5+ were accelerated up to 100 MeV and several experiments
were performed. In this period, the beam times for protons and newly accelerated ions wereincreased in contrast to the decrease for 2oNe 6 + and 14 N4 +.
Figure 2 shows the beam time of heavy and light ions over the past 8 years. Request forheavy ion beam continued to decrease, still the cyclotron was operated to accelerate heavy ionsfor more than 72 % of the total scheduled beam time in the past 3 years.

3

Table 2. Scheduled beam time and subjects of activity in the period XVII .
Subject
Nuclear reaction
Nucl. Phys.

{ RI production

In-beam spectroscopy

Nuclear chemistry
Fields others

Radiation biology

than Nuc!.
Phys.

Radiation chemistry
Solid state physics
Inner atomic shell excitation study

Heavy ion

Ligh t particles

2573 (h)44924302 (h)0802875 (h)
449
104

4
147
234
190
116

320
5
0
291
48

324
152
234
481
164

0
0

133
164

0

90

133
164
90

3737
72.3 %

1433
27.7 %

5170
100 %Study of radiation damage

Outside users f Nuclear fuel study

1RI Production

Total
Percent in total

Maintenance, operation and engineering
Exchange of ion sources

Total

96 (h)
560

Machine inspection and repair

656

Total

Table 3. Distribution of beam time among particles accelerated.
Particle(h)(%)

Particle

(h)

(%)

P

546
24
223
592
70
521
693

10.6
0.5
4.3
11.5
1.4
10.0
13.4

N5 +
2oNe 6+
13C4+a)180 5 +a)

765
574
500
592
70

14.8
11.1
9.7
11.4
1.3

Total

5170

100

d
3He++
4He++
7Li++
12C4+
N4+

a)

Newly accelerated ions.

0 5+

4

Q)

E

·ri

+l

!=:
C\l
<ll

.Q

'0

Ul

l-I

....<ll
1.0,g

NET BEAM TIMEk<ll

SCHEDULED BEAM TIME

..c::

0.9 ~

o

0.8 +l<llo• 7 .~+l

:::!
0

..c::

6000
NET BEAM TIME

Q)

!=:

·ri

+l

E

C\l

4000

Q)

/Xl

2000

1973

, 80

'75

'82

Calender year

Net beam time and the ratio of net
Fig. 1.
beam time to scheduled beam time.

o1974 '75 '76 '77'78'79 '80 '81 'B2Calendar year
~

~

-><-

Fig. 2.
history.

Heavy ionsLight particles
Total

The cyclotron beam time5

II -2.

Operation Statistics of RILAC

Y. Miyazawa, M. Hemmi, T. Inoue, T. Kambara, T. Kubo, Y. Chiba,
M. Yanokura, E. Ikezawa, T. Tonuma, M. Kase, and Y. Gono

The Riken heavy-ion linear accelerator, RILAC, started to supply beams of heavy ions in
the fall of 1981 for various experiments. Regular allocation of machine time to the proposed
experiments has begun since Feb. 8th, 1982. Initially , the ratio of time used for machinedevelopment and maintenance, experiments, and unscheduled shut-down by machine failure wasroughly I : 1 : 0.05. Percentage of beam time for experiments grew rapidly, especially after thesummer overhauling. In October, loss of time by machine failure became negligible whencompared to the time for the experiments and machine development. Though it is still necessary
to develop and improve the high power amplifiers to cover the whole intended frequency range,
the machine is stable enough for over-night operation. Table 1 gives statistics of operation fromFebruary to October in this year. Figure 1 shows the ion species accelerated in this period , andFig. 2 shows the area covered in the specification map of energy and frequency. Figures attachedto each line are the ratios of mass to charge of ions.

~ M. T.

5°1

J

450

~
::J

250

0

..c
(])

E
a.o
c

200

~
(])

n.

0

100

50

O ~~~~~~~-U~~LW=-~~LL-

Charge state 2

C

123

2

3

23

N O Ne AI

2346

456

56

78

Ar

Cu

Kr

Xe

Ion Spec ies

Fig. 1.

Statistics of ions used in the period Feb. 8- Oct. 23. Figures below abscissa give number ofcharge of each ion.

6

Table 1.

Statistics of operation in the period Feb. 8 - Oct. 31, 1982.

Schedule in this period
Beam time
Overhaul and improvement work
Periodical inspection and repair
Vacations and holidays
Total

Energy0.5

144 days

(54%)

43
24
55
266 days

(16%)

( 9%)
(21 %)(Me V/ n)

1

2

I

I

3
I

I

4 5
I

I i I

25
20

15

>
L
ill

tlO

2o
>

10

• C
N

u

x

u

«

+ 0

ill

>

o Ne

U

AI
Ar
@ Cu
~

ill

w

6

5

* Kr
Xc

Xe

Fig. 2.
Specification map and area
covered in the period of Fig. 1. The
area enclosed by broken lines gives the
specification of the linac. Smaller squareis the area intended to be covered ina few years, and the larger one later,
after the voltage holding capacity of
the cavity and the higher frequency
characteristics of the power amplifiersIii iii

15

I

Iii Iii I i i i i i i I I I

20AccFreg.

30

40( MH z )50

are improved. Figures at each line give
mass to charge ratios of ions to beaccelerated.

Heat exchangers of the water cooling system were found not functioning properly in June.
Temperature difference between the primary and the secondary coolant was much larger than
the specified value, suggesting something wrong has occured which hindered heat conduction
through plate separating the two coolant circuits. Also the mesh filter made of stainless steel ina liquid Freon circuit was discovered broken in small pieces. It was worried that the metalic
fragments might have flown into the cooling channel of the insulating liquid to destroy insulation.
Therefore, the regular summer overhaul interval was extended by a week and cleaning of theheat exchangers and inspection of the insulating liquid channel were done. A lot of remnant
pieces of the stainless steel filter was recovered from the Freon 123 channel. Black coloured mud
or slime was found sticking thick on the side of plate on which water from the cooling tower
flows. Table 2 shows temperature at the inlet and outlet of the heat exchangers. Note that thetemperature difference between the primary and the secondary channels decreased cons.iderably
after the overhaul. Also the pressure drop in the cooling tower water channel became small.

7

Table 3 gives the major machine troubles which caused the unscheduled shut-down of thelinac for more than a half day.

Table 2. Temperature and pressure at the inlets and outletsof heat exchangers of cooling system.
Sept. 9July 9Part

ChannelDeionized
water channel(Hex-3)

Cavitychannel(Hex- 4)!

Cooling towerwater side{

Deionized
water side{

Cooling towerwater side{

Cavity side

{

!

Inlet

Outlet

Diff.

Inlet

OutletDiff.

Temp. (C)

32

33.5

1.5

35

36

1.0

Pressure (kg/ cm 2 )

3.7

1.5

2.2

2.6

l.7

0.9

Temp. (C)

45

41.5

3.5

40

37

3.0

Pressure (kg/cm 2)

9.7

9.0

0.7

9.6

9.0

0.6

Temp. (OC)

32

33.5

1.5

35

1.0

Pressure (kg/cm 2 )

3.2

1.5

1.7

2.6

36
1.9

Temp. (C)

37

36.8

0.2

36.2

Pressure (kg/cm 2)

0.95

0.55

0.4

0.9

36
0.5

Table 3. Major troubles in the period Nov. 1, 1981 - Oct. 31, 1982.

Equipment

RF power
amplifiers

CavityTroubleTime required
for repair

Power tube failure due to vacuum degradation

1 day

Destruction of resistor in screen grids
power supply

1.5 days

Insulation failure of by-pass condenser ofscreen grids by water spray from a coolingpipe

1 daysLeakage of water from a cooling pipein the vacuum chamber

10 days

0.7
0.2
0.4

8

II -3.

TANDETRON-Operation

H. Sakairi, E. Vagi, T. Kobayashi, and T. Urai

During one year from the November in 1981 the machine was operated for 134 days in total:
88 days for experiments and 46 days for tests.
Subjects of the experimental studies were as follows:(1) Application of backscattering spectroscopy,(a) Effects of ion implantation on properties of electrodes,(b) Improvement of corrosion-resistance of steels by ion implantation,(c) Electrical conductivity of an ion implanted diamond,(d) Laser annealing effects on ion implanted GaP,(e) Lattice location of Sn atoms implanted into Al crystals,(2) Application to the fields other than backscattering spectroscopy,(f) Ion induced X-ray spectroscopy of chemical effects,(g) PIXE analysis of dried bloods,(h) Heavy ion radiation damage of metals.
Species of ions which were newly utilized to the experiments this year were boron and carbon.
The condition of operation and resulted beam intensity for them are shown in Table 1.
In the first half of this year troubles occured frequently in the lithium vapour canal; lithium
vapour liquidified to make a membrane at the beam path in the canal. This situation was
improved greatly in the last half of the year.
Table 1.

Ion

Operating conditions and beam intensity.

Negative ion
beam intensity

Accelerationenergy(MeV)

Beamintensity(IlA)

Terminal
voltage
(MV)

1.0

1.0

2.4

0.34

7

0.7

1.4

0.6

10

0.7

2.8

0.9

(IlA)

9

III.

RESEARCH ACTIVITIES

1.

Nuclear Physics
1.

Excitation Functions for l4N-lnduced Reactions on 62Ni

K. Sueki, Y. Hamajima,* M. Takahashi,*
Y. Nagame,':!* H. Nakahara, and 1. Kohno

4

NUCLEAR REACTIONS 62Nict N , X), E Lab = 40 - 120 MeV, measured crossJ[ sections, excitation functions; calculation statistical models.

The aim of the present work is to measure the excitation functions of evaporation-like
residues in the 14N + 62Ni reaction and to see if the reaction mechanism leading to those products
can be understood in terms of the ordinary model of compound formation and evaporation.
Self-supporting 62Ni target foils of I - 2 mg/cm 2 (isotopic abundance 98.5%) were preparedby electrodeposition. They were assembled into a stack together with Al foils (5 - 6 mg/cm 2) of
99.997 % purity which served as collectors of recoiling products and beam energy degraders.
Irradiations were performed at the cyclotron with initial beam energies of 95 MeV and 120 MeV
for 1 - 2 h with beam intensities of 100 - 200 nA. The beam energy incident on eachtarget was estimated from the range-energy table of Northcliffe and Schilling,1) and the energy
range covered was from 40 to 120 MeV. The cross sections were determined by directly
observing the ')'-rays of the reaction products with a Ge(Li) detector.
The excitation functions obtained in this work are shown in Fig. 1(a), 1(b), and 1(c). The
cross sections of 73Se, 71 As, 69Ge, 67 As, and 65Ga are corrected for the contributions from therespective parent nuclides in the ~-decay chain, and thus they are the so called independent yields.
The cross sections of the parent nuclides of 70As and 66Ga were found below 10 mb, which isthe detection limit in this work. Therefore, yields of 70As and 66Ga can approximately beconsidered as independent ones. The nuclides, 74m Br, 72As, and 68Ga, are shielded nuclides in therespective ~-decay chain and their observed yields are also independent yields.
The excitation functions in the present energy region can be classified into two groups: (1)74mBr, 73Se, and 72As which exhibit simple peaks revealing that they have simple reaction
channels; and (2) the products with the mass number smaller than 71 which show two peaks,
suggesting that they are produced by various evaporation channels.
The experimental results are compared with predictions of the statistical evaporation modelby using the codes, ALICE 2) and GROGI2. 3) The decay rate of the compound nucleus,
R(E a , J : E f , i, s) are given by.
dE f n(Epj)
R(E c ' J : E f , J, s)dE f = -T n(Ec'J')

j~S(1)
S = I j-s I* Faculty of Science, Tokyo Metropolitan University.
** Present address: Japan Atomic Energy Res~arch Insitute, Tokai.

f. = I J - S I

10

(b J

( c)

o 7~I11Br

• "Se
0

10

72

As

2

::0-

.D

E

E

c

c

::0
E

9

~
u

<1>

(/)

c

o

u

~ 10' 1-

~ 10'

10'

~

(/)
(/)

(/)
(/)

o

0

U

U

0
•

7

' As

70

As

~

o

U

o 69 Ge10°ni
10 - '50

E.v( M eV )Fig. 1.
Excitation functions of evaporation-like residues:(a) 74mBr, 73Se, and nAs ; (b) 71As, 7oAs, 69Ge ; (c) 68Ga, 67Ga, 66Ga, and
65Ga. The lines are drawn though experimental points to guide the eye.
where Ec denotes the excitation energy of the compound nucleus, and E f denotes the energy of
the residual nucleus. J, j, and s are the angular momentum of the compound, residue, and theparticle emitted from the compound nucleus, respectively. n is the level density, and T f is thetransmission coefficient for the orbital angular momentum .e. In the ALICE code it is assumed thatdn(E,J)o:(2J + 1)dn(E), and thus, Eqn.(l) can be written as

L
f=O(2f + I)T f .

(2)

In the GROGI2 code the calculation is made using Eqn.(l) which rigorously takes into accountthe angular momentum conservation. In both of the codes almost identical level densities andtransmission coefficients are employed. The GROGI2 calculation is now still in progress, andonly a part of the results are given here.
In Fig. 2 are shown the excitation functions of experimental and calculated results for 73Se,
n As, 71 As, and 70As. In the calculation, the critical angular momenta which were estimated fromthe empirical data reported for 4N + 58Ni) and (14N + 62Ni) reaction systems 4) with the aid ofct

the· Bass model 5) were supplied as inputs. The figures show that (1) the predictions by ALICE
are in all cases shifted in energy by about 20 MeV to the lower energy side of the experimental
points, and that (2) the GROGI2 code gives better overall agreements, but for 73Se and nAs theexperimental results are larger than those expected at the high energy region of excitation
functions. These observation indicate that the observed excitation functions can be understoodfairly well by the evaporation model if the effect of the angular momenta of emitted particles
are taken into account rigorously. However, the observed discrepancy for 73Se and nAs may
indicate the possibility of incomplete fusion processes at higher incident energies. This conclusion
is also supported by the results on the differential projected ranges of 73Se observed in the 115
MeV 14N + 62Ni 6) which could only be explained on the assumption of higher energy 3H particle
emissions.

11,..--....

10'

I •
10 1

-D

10°

E

.

l .\ .

/"'\.

\ ••

/.

\ .: .
~

I
.

.\ .·

I

\

r.)

c

\ .

~

~
Q)

(f)
(f)
(f)

0

0

10 2

Fig. 2.
Comparison between experimental excitation functions (closed
points) and the predictions by the codes ALICE (solid line) and GROGI2(dot-dashed line): (a) 73Se, (b) 72As, (c) 71As, and Cd) 7oAs.

ReferencesI)
2)

L.C. Northcliffe and R.F. Schilling: Nucl. Data Tables, A 7, 233 (1970).
M. Blann and F. Plasil: U.S. Atomic Energy Comission Report N° COO-3494-10 (1973)

3)
4)
5)
6)

(unpublished).
J .R. Grover and J. Gilat: Phys. Rev. , 157,802 (1967).
M. Yanokura, H. Nakahara, and I. Kohno: J. Phys. Soc. Japan, 50, 369 (1981).
R. Bass: Nucl. Phys., A231, 45 (1974).
Y. Nagame, M. Watanabe, H. Kudo , .K. Sueki, and H. Nakahara: Accepted in Radiochim. Acta.

12

III -1-2.

Strongly Damped Components in the Reactions of

2°Ne + 92 Mo and 2°Ne + looMo Systems

1. Kohno, Y. Nagame, K. Sueki, M. Takahashi,* and H. Nakahara,.-l

NUCLEAR REACTIONS 20Ne + 92Mo, 20Ne + looMo; strongly damped]
components, Z(atomic number) distrib.ution, target isotope dependence,

diffusion model, rotating liquid drop mode1.

The reactions of lONe + 92Mo and 20Ne + 1~0 systems were investigated experimentally. The strongly
damped components, especially, symmetric mass fragmentation products were analyzed in terms of the diffusion
model 1) as well as the rotating liquid drop model 2) for fission. The systems studied in this work, the conditions forcompound nucleus formation and its decay by fission are summarized in Table 1.
The details of the experimental procedure are similar to those for the reaction of 20Ne + sOCr reported ina previous report. 4) The experimental results such as grazing angle(e gr)' reaction cross section (or) and criticalangular momentum (Q cr) obtained from elastic scattering and evaporation residue cross section data are summarizedin Table 2. The trends of the energy spectra obtained in the 146 MeV 20Ne + 92Mo and 20Ne + l~O systems are

similar to those observed in the 146 MeV 20Ne + 50Cr reaction. 4 )Table 1. Summary of the conditions for compound nucleus formation and its decay by fission.

a)Reaction

a)

ECN

x

fcrit

c)
PBf=BnBf at fcrit

(MeV)

(n)

(n)

(MeV)

b)

CompoundFissility

nucleusparameter

Elab
(MeV)

112Te

0.479

146

103.7

61

60

10.9

120Te

0.453

146

118.2

64

70

15.3

compound nucleus excitation energies.

b)

Bass model. 3)c)fBf=Bn characterizes the £, value at which the fission barrier Bf coincides with neutron binding energy.

Table 2. Experimental results obtained from elastic scattering and evaporation residue
cross section data.
Reaction(j crn( deg)gr

Pgr (h)a/mb)aER(mb)£crit(h)ECM(MeV)

V/MeV)~Ne + 92Mo

37.7 ± 0.5

72 ± 11780 ± 24

1001 ± 50

54 ± 3120

59.5

lONe + looMo36.4±0.574 ± 21844 ± 251021 ± 53

56 ± 3122

58.7* Department of Chemistry, Tokyo Metropolitan University.

13

The charge distributions observed in the 146 MeV 20Ne + 92Mo and 20Ne + 1~0 reactions are shown in
Fig. 1. The cross sections of particle emission decrease towards larger Z value from the projectile Z = 10 andhave minimum values at the Z value of 16. Above the Z value of 16 broad peakings at around Z = 26,
corresponding to a half value of compound systems are seen. Furthermore, the yields above Z = 15 were found
1 03 L1---------,-------~--------.---------~
1-------,-= 26. 3°o 2° Ne + ~2 Mo(J' a"• 2IJN e + IIlIlMo(J' il" = 25. 3°

o

o

-

o

•
o

-

.... • • •

o
00 0
•

0

o

••

-

10- 1~1~------~~
1 ------~1~------~1~------~1~------~

5

10

15

20

25

30

z
Fig. I.
Experim ental charge (Z) distributions obtained
from the reactions 146 MeV 20Ne + 92Mo and 20Ne + looMo.

- - 2°Ne+ 92 Mo---- 20 Ne + loo Mo(Jcm =30 °, t y, = 1O- 2l sec

10°

10- I

,,
,,
'.

5
~------~--------L-------~------~--~--~
30

Z
F ig. 2.
Charge distributions calculated by the diffusion
model. The solid line shows the distribution of 20Ne + 92Mo
arid the dashed for the 2~e + looMo .

14

to be about two times larger for the 2D:Ne + 92Mo system than for the lONe + looMo system, while the difference
was not observed in the products lighter than Z = 13.
If it is assumed that the transfer of charge Z or mass A conforms to the diffusion phenomena, the charge
distribution is calculated by the same method as in the previous report. S) Figure 2 shows the calculated charge
distributions for lONe + 92Mo and 2D:Ne + looMo systems. In this figure the cross sections below Z = 15 which
are decreasing towards larger Z agree with the experimental results, while the broad peakings above Z = 16 are notfound and also the isotopic dependence of the cross sections above Z = 15 is not found.
In order to explain the cross sections above Z = 16 the statistical analysis of the fission cross section a FISS
was carried out by the computer code OVERLAID ALICE. 6) The comparison of calculated fission crosssections with the experimental cross sections of symmetrically split products obtained by summing up the crosssections above Z = 16 is shown in Table 3. The ratio of the calculated cross section for 20Ne + 92Mo to that for
lONe + looMo is nearly equal to the ratio of experimental results.
From the above experimental results and analysis of these results, it is suggested that, in the strongly damped
components of the reactions 146 MeV lONe + 92Mo and lONe + looMo, the particles with the Z value below 15 areemitted by the deep-inelastic collision, while the particles with the Z value above 16 are mainly fission productsof the compound nuclei.

Table 3. A comparison of calculated fission cross sections with the ones
extracted from the experimental charge distributions.
Reaction
22 ± 517.3

12 ± 4

7.66

References
1)

W. Norenberg: J. Phys. C5, 37, 141 (1976); S. Agarwal, J. Galin, B. Gatty, D. Guerreau, M. Lefort, and

2)

X. Tarrago: Z. Phys., A296, 287 (1980).
S. Cohen, ·F. Plasil, and W.J. Swiatecki: Ann. Phys., 82, 557 (1974).

3)
4)

R. Bass: Nucl. Phys., A231, 45 (1974).
Y. Nagame, I. Kohno, M. Yanokura, H. Kudo, and H. Nakahara: IPCR Cyclotron Progr. Rep., l±, 34 (1980).

5)

Y. Nagame, I. Kohno, H. Nakahara, H. Kudo, K. Sueki, M. Takahashi, and M. Yanokura: RIKEN Accel.

6)

Progr. Rep., 12.,33 (1981).
Blann, M.: U.S. ERDA No. COO-3494-29, Rochester (1976). (unpublished), "OVERLAID ALICE: A
Statistical Model Computer Code Including Fission and Preequilibrium".

15

III-1-3.

High-lying Proton Strengths Observedin (12 C,

11B ) Reactions*

M. Ishihara, E. Takada,** T. Murakami,***E. Ungricht,*** Y. -W. Lui,*** R. Tribble,***Y. Toba,*** and Y. Mihara***

NUCLEAR REACTION ( l2 e, lIB) and ( l2e, He) onj
144Sm etc. E = 180 MeV; population of single-particle[ states.

In this work, we have investigated heavy-ion one-nucleon transfer reactions, ( 12C, 11B) and( 12C, l1C) on various heavy target nuclei. The primary aim of the investigation is to test thecapability of those reactions in populating high-lying single-particle states relevant to the major
shell 1 hw above the Fermi level. Such possibility for the stripping reactions may be inferred inview of the situations for one-nucleon pickup reactions, which have been known 1) to be useful inlocating single-particle hole strengths for deeply bound states as well as state close to the Fermi
level. We have used the heavy-ion projectile 12C, anticipating that the selectivity due to matchingconditions of the heavy-ion reactions may help to obtain simplified energy spectra in favour ofhigh-spin-state population. Indeed we have found the reactions to be quite useful in exciting
high-lying single-particle states.
The experiment was performed using 180 Me V 12C ions from Texas A & M A VF Cyclotron.
A variety of target nuclei, such as 90Zr, 118sn, 144,148, 154Sm, 208Pb were bombarded. Energy
spectra and angular distributions were observed by detecting and identifying ejectiles with sets of
Si-detector telescopes.
A typical result is illustrated in Fig. I, where the l1B energy spectrum at 17° for the
144Sm( 12C, l1B) reaction is shown. Besides the low-lying peaks (denoted by 2d5/2 and 1hll/2 ),two strong broad peaks are seen at higher excitation energies as indicated by "a" (at"" 6.0 MeV)
and "b" (at"" 7.5 MeV). These peaks are well distinguished from the underlying continuum(dashed line), which is typical of quasi-elastic reactions with Gaussian-like shape peaked at energy
corresponding to the incident beam velocity. The l1B spectra for other targets showed similar
structures at high energies, though they are less distinguished than those for 144 Sm target. The
spectra for the ( 12 C, l1C) reactions also showed selectively populated peaks. However theexcitation energies for those states are relatively low as compared to the cases of ( 12e, l1B)
reactions, probably reflecting the difference in matching conditions associated with the Coulomb
energy difference between incident and outgoing channels.
*

This work is made under the auspice of the US-Japan research collaboration program funded by Science and Technology
Agency of Japan.

**

Department of Physics, Osaka University.

***

Texas A & M University, Cyclotron Institute.

16

2 000
144 Sm( 12 C,

liB ) 145 Eu

180 MeV
8= l r}:' =/Ih 11 / 2a~

; 1 000ouFig. 1.

Energy spectrum of lIB observed at
17° in the 144Sm( 12C, llB)145 Eu reaction at

180 MeV. Two broad lines denoted by a andb, respectively, correspond to excitationenergies of"" 6.0 and"" 7.5 MeV. The peakc is partly due to excitation of lIB at theChannel

2.14 MeV 1/2- state. The dashed line
indicates the shape of continuum background.

On the basis of excitation energies, the broad peaks in Fig. 1 are supposed to be associatedwith excited states in the next upper major shell. Inspection of matching conditions may thensuggest that two highest-spin states, li13/2 + and 1h9/2 - , are plausible candidates for those peaks.
Quite recently, study of one-proton transfer on the same target in (d,t) and CHe, d) reactions has
been reported. 2) The spectra observed in those reactions are very similar to those for the( 12C,lIB) reaction. Analysis of the (a, t) angular distributions indicated that the peaks "a" and"b" are, respectively, ascribed to .e = 5 and 6 transitions.
In earlier experiments with heavy ions, such high-lying single-particle strengths have neverbeen identified. In some cases, the failure may be attributed to use of ions with insufficientenergies: Indeed the comparison of the data for 90Z r( 12C, lIB) reactions at 180 MeV (present
study) and at 98 MeV (Ref. 3) shows that population of high-energy high-spin states are moreenhanced for the higher-energy bombardment. There have also been studies 4 ) using high-energy
heavy ions. However use of inappropriate projectiles seems to have hampered to obtain clean
spectra. For instance, 15N ejectile from (160, 15N) can be strongly excited particularly at 6.4 MeV
1 P3/2 hole state, yielding kinematically broadened structure which disturbs the energy spectrum inthe high-energy region of interest. For the case of ( 12C, lIB), such ejectile excitation was found tooccur only weakly as represented by the peak lavelled with "c".
The present study has revealed that heavy-ion reactions can be useful for the study ofsingle-particle strengths ranging to high energy regions. Augular distributions observed, however,show very similar bell-shaped patterns for different peaks, demonstrating little capability ofheavy-ion reactions in distinguishing transferred .e values. This deficiency of heavy-ion reactions
as compared to light-ion reactions may possibly be compensated by the advantages such as follows:( I ) Population of observed high-lying states relative to that of low-lying states appears to bestronger in the heavy-ion reactions than in the light-ion reactions. (2) It is probable that strong
j dependenceS) of population arising from matching conditions may be exploited in heavy-ion

reactions to easily distinguish between j > and j < states. Such aspects are presently undersystematical investigation using different heavy-ion projectiles with varied energies and also
comparing with data from (a, t) reactions.

17

References
1)

2)
3)

e.g., S. Gales: Nucl. Phys., A354, 193C (1981).
S. Gales, C.P. Masso10, S. Fortier, E. Gerlic, J. Guillot, E. Hourani, J.M. Maison, J.P.
Schappira, B. Zwieg1inski, P. Martin, and V. Comparat: Phys. Rev. Lett., 48, 1593 (1982).
S.T. Thornton, D.E. Gustafson, J.L.C. Ford Jr., K.S. Toth, and D.C. Hensley: Phys. Rev.
C,~

4)
5)

1502 (1976).
e.g., C. Olmer, M. Mermaz, M. Buenerd, C.K. Gelbke, O.L. Hendrie, J. Mahoney, D.K. Scott,
M.H. Macfarlane, and S.c. Pieper: ibid. , ~ 205 (1978).
P.D. Bond, J. Barette, C. Baktash, C.E. Thorn, and A.J. Kreiner: Phys. Rev. Lett., 46,
1595 (1981).

18

III-1-4.

Polarization Measurement for Continuous Protons Emitted
in the (a, p) and (14N, p) Reactions

T. Nomura, S. Kohmoto, K. Sueki, T. Kubo,
H. Kudo, and H. Utsunomiya

NUCLEAR REACTIONS 27A1ct4N,p), 59Coct4N,p), E = 95 MeV, 181Ta(a,p)'1
E = 40 MeV; measured spin polarization of protons (fJ = 45°, 120°).
[

Double scattering method.

Spin polarization of protons having continuous energy distributions emitted in the (14N, p)and (a, p) reactions have been measured by the double scattering method using a new polarimeterwith large efficiency. The present polarimeter uses a carbon plate of about 34 mg/cm 2 inthickness as an analyzer (the second target), and is very similar to that used for the previous
measurement in the 93NbcI4N, p) reaction at 95 MeV!) except for the following points:(1) An average second scattering angle is chosen to be S0° .
(2) Large (200 mm 2 ) counter telescopes consisting of Si 6E (SO ,urn) - E (2 mm) detectors
are used to measure protons'scattered by the analyzer. Rectangular slits of 8 mm in width and
13 mm in height are inserted in front of these asymmetry counters. This makes it possible touse large solid angles without decreasing analyzing powers very much.
(3) A 100 ,urn Si detector is used as an 6E1 counter. A rectangular slit of 3 mm in widthand 8 mm in height is placed 12 mm before the analyzer.
The solid angle of the carbon analyzer looking at the beam spot is 17.3 msr, while both theasymmetry counters have solid angles of 170 msr. These values are about three times as large as
those of the old polarimeter. 1)
The spin polarization was measured at 4So with respect to the beam direction by bombarding
27 Al and 59Co targets with 95 MeV 14N beam as well as by irradiating a 181Ta target with 40 MeV
alpha beam. The measurement was also made at 120° in the case of the 59Co(14N, p) reaction.
A preliminary analysis of the data has yielded the following features:(1) The polarization is close to zero in the case of the 27Alct 4N, p) reaction at 4So,
(2) In the 59Co(14N, p) and 181Ta(0', p) reactions at 4So, the polarization is positive for highenergy protons (Ep > 12 MeV), but is smaller than the values obtained in the 93Nbct4N, p) reaction
at 40° described previously. 1)(3) The polarization is likely to be negative in the case of the 59Co( 14N, p) reaction at 120°.
A more detailed analysis is now in progress.

Reference
1)

T. Sugitate, T. Nomura, M. Ishihara, Y. Gono, H. Utsunomiya, K. Ieki, and S. Kohmoto:Nucl. Phys., A388, 402 (1982).

19

III-1-5.

Angular-Momentum Transfer and Alignment Following
Preequilibrium a-Particle Emission in
0_ and 2°Ne~lnduced Reactions

16

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

NUCLEAR REACTIONS WCJsie60, at), E = 120 MeV, 209Bie<Ne , at),

J

[ E = 146 MeV; measured angular correlations; deduced I and Pzz .

The average magnitude and alignment of angular momenta transferred to fusion-like products
resulting from preequilibrium a-particle emission have been determined by a-f angular correlation
measurements in the reactions of 209Bie 60, af) and 209Bie~e, af), in which the residual nuclei
following the a-particle emission partly decay via fission.
A self-supporting 209Bi target of 0.8 mg/cm 2 thickness' was bombarded with 120 MeV 160_ and
146 MeV 2~e-ions from the cyclotron. Alpha particles were detected with Si .0.E(50 ,um) - E(2 mm)counter telescopes, while fission fragments were measured in a 30 ,urn Si detector. The experimental
arrangement for the present measurement was the same as described in our previous work.l)
Figure 1 shows the measured in-plane and out-of-plane angular correlations, in which thea-particles were detected at 20° and 50° with respect to the beam direction. The analysis of theexperimental data has been made in the same way as described in Ref. 1. The K-distribution ofa fissile nucleus is assumed to be gaussian, in which the width parameter Ko has been estimatedfrom the temperature and the moment of inertia at the saddle point following the procedure given
in Ref. 2. Then, the angular correlations depend on the average magnitude I of angular momenta
of a fissile nucleus and their alignment along the normal (z-axis) to the reaction plane. We fitted
the data by assuming one-dimensional dealignment of the spin vector I, which is expressed byeither (A) or (B) given below:(A) I is composed of random coupling of a component 11 completely alined along the z-axis
and a component 12 uniformly distributed in a plane perpendicular to the recoil direction(x-axis) of the fissile nucleus, i.e., I = 11 + 12 ; adjustable parameters in the fit were taken to
be the magnitude of I and 12 ,(B) The polar angle (3 of I is distributed by exp( - (32/2(36), where the magnitude of I and (30were taken as the fitting parameters.
The results are given in Table I, where the average entrance angular momentum fj for preequilibrium
a-particle emission calculated from .e.1 = AI/(A - 4) (A is the mass number of projectile) and thecritical angular momentum ecr for complete fusion estimated from a model of Wilczynski 3) arealso given for comparison. It is clear that fj is considerably smaller than Pcr in both reactions.
Note that the value of I presently deduced generally gives the upper limit of angular momentatransferred to a residual nucleus produced via a-particle emission, because higher spin states of
the residual nucleus decay by fission more preferentially. I)* Hitachi Computer Engineering.

20

OUT·OHlAIiE

III·PLUE

=1860

~
lab

•

~
•

if!

= 1920

lab

•

15D

II.

ZID

HO

210

60

90

Fig. 1.

60

3Q

120

8 cm (deg.)¢cm(deg.)

150

180

210

2.0

210

90

60

30

¢cm(deg.)

The experimental a-f angular correlations taken in the reactions of209Bi( 160, af) at 120 MeV and

209BieCNe, af) at 146 MeV, where a particles

were detected at 20° and 50° with respect to the beam direction. The polar
angle () is taken from the normal to the reaction plane defined by the
direction of the measured a particles and the beam, while the azimuthal
angle ¢ is taken from the recoil direction of the fissile nucleus. The solid
curves show the best fits by method A.

Table 1.
Beam

MethodResults of the analysis.

I

30 ± 4f.
1

26

35 ± 528 ± 21732 ± 42<Ne{~

40 ± 4{~36 ± 238

0.46

40 ± 50.39

47 ± 70.74

37 ± 30.66

43 ± 50.31

50 ± 50.28

55 ± 50.63

45 ± 30.55

51 ± 553
53

60
44 ± 42560
41 ± 4

All angular momenta are given in unit of nand PlZ = ~< I; >1< 12 > - 0.5.

21

The analysis based on two-dimensional dealignment of I (non-zero x-component of I) madein the same way as in Ref. 1 has resulted in an increase of I only by 1-2 h and does not affectthe above conclusion (li < fer) seriously. The present result therefore indicates that thepreequilibrium a-particle emission in the present reactions mainly originates from impact parameters
ensuring enough overlap of projectile and target nuclei. This supports an interpretation that thea-particles of interest are emitted as the precompound decay during the fusion process.

References
1)
2)
3)

H. Utsunomiya, T. Nomura, M. Ishihara, T. Sugitate, K. Ieki, and S. Kohmoto: Phys. Lett.,
l05B, 135 (1981).
B.B. Back and S. Bj¢rnholm: Nucl. Phys., A302, 343 (1978).
J. Wi1czyski: ibid., A216, 386 (1973).

22

III -1-6.

light-Particle Emission in

7li-lnduced Reactions

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

NUCLEAR REACTION 159TbCLi, Xl'), 232ThCLi, xf), E = 77 Mev]~

x = p, d, t, a; measured aCE, 8), angular correlations; deduced spinalignment, transferred angular momenta.

The light-particle emission has been studied in coincidence with l'-rays or fission fragments resulting fromfusionlike residual nuclei following 7Li-induced reactions on 15~b and 231il in order to deduce the magnitude andalignment of the transferred angular momenta in the relevant emission.
12

24

36

48

o

12

24

48
159

60

72

84

Tb+ 7 Li
E=77MeV.. 10°
• 15°
o 25°
6 35°
x 45°
o 55°
o 75 °
y
135°

•

~~~

2

<i

i

Gl

2£

f

???

!f
H

~

10-2~~--~--~L-~~~~--~--~--~--~--~--~--~~

o

12

24
36
48
EJab (MeV)

Fig. 1.

o

12

24

36 48
60
E Jab (MeV)

72

Some energy spectra of protons, deuterons,

tritons and a particles observed at various angles in thelS~b + 7 Li reaction at 77 MeV. The laboratory angles
are indicated.

* Institute for Nuclear Study, University of Tokyo.
** Faculty of Science, Tokyo Metropolitan University.

84

23

The experiment was performed with 77 MeV 7Li ions from an INS cyclotron. A self-supporting 159yb targetof 3.2 mg/cm 2 thickness and a 23~h target of about 0.5 mg/cm 2 thickness electrodeposited onto an Al backing
was used. Some energy spectra for p, d, t, and a measured in singles in the 159yb + 7Li reaction are shown in
Fig. 1. At very forward angles the spectra exhibit a bump at around an energy corresponding to the beam
velocity, suggesting the breakup mechanism as a dominant origin of the light-particle emission. This feature isvery clear for the case of tritons and a-particles, while it is less visible for protons and deuterons, presumably due
to the cluster structure of 7Li. The a-particle spectra were also taken in coincidence with 'Y-rays from the
159TbCLi, axn)162-X Dy reactions. The spectra obtained after the summation over those from all axn channels are
similar to singles spectra, although the bump around the beam velocity are less pronounced, suggesting that the
breakup-fusion process takes place to a considerable extent.
Figure 2 shows out-of-plane angular distributions of 'Y-rays characteristic of various axn channels, which were
measured in coincidence with a-particles at 30°. The same measurement was also made at ljJ a = 60°. They werefitted by assuming that the population parameter of each initial state is given by(1)
where 1 is a spin of the initial state which emits 'Y-rays of interest and m is its component along the normal to thereaction plane. The result is given in Table l.
In-plane and out-of-plane angular distributions of fission fragments measured in coincidence with lightparticles emitted at 20° in the 23~h + 7Li reaction are shown in Fig. 3. They were analyzed in the same way as
described in a preceeding paper. 1) The result is given in Table 2. The following points should be noted:(1) The alignment (P zz ) of the transferred angular momenta (1) for the case of a-particle emission is close
to that obtained from the analysis of the 'Y-ray angular distributions (see Table 1), except for the aSn channel,
where the a-particle energy is very low and thus the evaporation process must be dominant.
(2)

The sum of 1 for triton and a-particle emission is almost equal to the grazing angular momentum inthe 23~h + 7Li reaction at the present energy. Note that this sum corresponds to the entrance angular momentum
if tritons and a-particles originate from 7Li breakup and one of them can be considered as a spectator while theother is captured by a target nucleus.
The second feature is in sharp contrast with conclusions of Refs. 1, 2, where the average entrance
angular momentum for preequilibrium a-particle emission in 1~_, 160 _, and 2~e-induced reactions is considerably
smaller than critical angular momentum for complete fusion at each reaction, which is of course even smaller than
the grazing angular momentum . It is also interesting to note that the value of P zz for triton and a-particle emission
in the 7Li-induced reaction is much larger than that obtained in Refs. 1, 2 at the same emission angle.
The above facts can therefore be considered as characteristic features of the breakup-fusion process.

Table 1.

Emissionangle of a

The best fit parameters in the analysis of the 'Y-ray angular distributions.
P zz is calculated from P zz = { 3<m 2> -1(1 + 1) } /1(21- 1).
ReactionchannelTransition1--*1'

0/1

Pzz

a2n

6+ --* 4+

0.23 ± 0.02

0.62 ± 0.04

a3n

17+/2 --* 13+/2

0.23 ± 0.01

0.60 ± 0.02

a4n4+ --* 2+

0.26 ± 0.01

0.61 ± 0.02

a5n

21 +/2 --* 17+/2

0.37 ± 0.04

0.33 ± 0.05

a4n4+ --* 2+

0.29 ± 0.02

0.56 ± 0.04

aSn

17+/2 --* 13+/2

0.50 ± 0.06

0.24 ± 0.05

4+ --* 2+

0.71 ± 0.22

O.l5±O.lO

1 a6n

24

3.0'----'1.------r------~1-----~
1-----.

15 9 Tb( 7 Li, axn) 162-X Dy

2.5 -

-

~\ ::~: ~~2¥+>f-- 2.0 fU5
Z

W

-

f-Z

-

1.5

~~WI
I

I

90

60

232Th('Li , xf ).......

~

~~

::>
>-

'"
.D
~

IOj

DEUTERON--'~--Y+ ---.

+~TRITON--'--::::::::-::1--

ALPHA

-~
~~

DEUT ERON~~t-::j-0-1

f ~m-1-:::.-,_._.

.=-.-=:;_e ':::::.f--i--~

PROTON

1 · ~~~.

lot ~~•~HA

t ~f~.'
CPcm (deg)with fr particles .at 30° in the lSCJrb + 7U reaction at 77
MeV. The solid curves show the best fits.

OUT- OF- PLANE

PROTONcFig. 2.
Out-of-plane angular distributions of
discrete ,),-rays from 162-XDy measured in coincidence

x=p, d, t , a

IN- PLANE; %,,"+o30-

Oem ( deg)

Fig. 3.
In-plane and out-of-plane angular distributionsof fission fragments measured in coincidence with
protons, deuterons, tritons and a particles emitted at
20° in the 232ThCLi, xf) (x = p, d, t, fr) reaction at
77 MeV. The best fits are given by solid curves.
The dashed and dotted-dashed curves correspondto the fit with the lower and upper limit of J
within one standard deviation, respectively, showing
the sensitivity of the fit on J.

25

Table 2. The best fit parameters obtained for the reaction 23urhCU, xi) (x = p, d, t, a) at 77 MeV.
All symbols refer to Ref. 1. The angular momenta are given in unit of n and ~o in degrees.

Emittedparticles

P

d

J

J2

A

32 ± 731B

36 ± 8A

27 ± 6B

29 ± 7A

21 ± 5B

21 ± 6

A

20 ±4

B

22 ± 4

Method

!
!
!
!

P zz

~o

030 ± 0.02
.
0.01
69

0.39 ± < 0.01
0.31±<0.01
0.06

26
71

0.38 ± 0 .01
0.10
0.51 ± 0.16

17
41

0.03
0.56 ± 0.09
063 + 0.16
. - 0.14

14
35

6

0.03

o. 3 ± 0.08

References
1)
2)

T. Nomura, H. Utsunomiya, S. Kohmoto, and M. Sasagase: p. 19 in this report.
H. Utsunomiya , T. Nomura, M. Ishihara, T. Sugitate, K. Ieki, and S. Kohmoto; Phys. Lett., 105B, 135(1981).

26

III -1-7. Momentum Transfer Light-Particle Emission Following
210 MeV 14N-Bombardment on 232Th

T. Nomura, T. Fukuda,* H. Ogata,** 1. Miura,**K. Katori,* T. Shimoda, and S. Shimoura***232ryhe~,xf),

x=p,d,t,a, E=210 MeV; measuredl
NUCLEAR REACTION[ 0x(e, E), x-f-f angular correlations; deduced momentum transfer.

J

The laboratory angle (8 if) between two fission fragments in a binary fission depends on themagnitude and the direction of linear momentum carried by a fissioning nucleus in the laboratory
system. The distribution of 8 if in a nuclear reaction using a target nucleus with large fissionability
ALP" MOM. TAA. LOI.l(Sr

---

10 2

>
Q.l

:c

x

.,

10 I

z

o

t;

w· 1

W
(fl
(fl.

~

10-

2

'0:

W

ALrA MN. TRA . MIDDLE

z
;::

laO

I-

w
W
(fl
(fl

la-I

(f)

o
0:

w

ALPA MON. TRA. H IGHES T!

Fig. 1.

10

1

-

w

w
(fl

(/)
(fl

o
0:

w

Department of Physics , Osaka University.

** Research Center for Nuclear Study, Osaka University.
*** Department of Physics, Kyoto University.

Energy spectra of a particles
observed at 33° in coincidence with two
fission fragments; the three spectra
correspond to those of low, middle andhigh momentum transfer to thefissioning nuclei (see text).

27

therefore determines the distribution of momentum transferred from the projectile to the target.
In this work we have measured the ejf distribution in coincidence with light particles emitted in
the 232Th + 14N reaction to deduce possible missing momentum carried by unobserved particles.
A 232Th target was bombarded with 210 MeV 14N ions from a cyclotron at RCNP (ResearchCenter for Nuclear Study, Osaka University). Fission fragments were measured with two position
sensitive detectors placed near 90° and 270° with respect to the beam direction, while lightparticles (p, d, t, and ex) were measured at the emission angles (ex) of 10°, 20°, 33°,44°, and 55°
with counter telescopes consisting of Si and Ge detectors. The eif distribution in this set-up issensitive to the momentum component (L:;p) of the fissioning nucleus along the beam direction.
Figure 1 shows energy spectra of ex particles observed at ex = 33° as examples; the three spectra
shown correspond to those yielding low (L:;p < 0.25Pmax)' middle (0.25Pmax < L:;p < 0.5Pmax) andhigh momentum transfer (L:;p > 0.5Pmax)' where Pmax is a value of L:;p corresponding to the fullmomentum transfer obtained under the assumption that even the observed particle carries no
momentum.
The preliminary analysis has yielded the following features for the ratio of L:;Pav /L:;pmax' where
L:;Pav is the average value of L:;p, and L:;pmax is the maximum magnitude of available momentum
transfer, i.e., a value of L:;p when no missing momentum exists. Note that the momentum of theobserved light particle is taken into account to estimateL:;pmax' so that L:;pmax is different from
Pmax .
(1) The ratio of L:;Pav/L:;pmax is nearly independent of kinetic energy (E) of observed lightparticles over the wide range of Ex' The energy averaged values of this ratio at ex = 20° arearound 0.75 for proton, 0.68 for deuteron, O· 65 for triton and 0.55 for ex particle.
(2) The above ratio is smallest at ex = 10°, and increases monotonically with increasing ex'
A detailed analysis of the data is now in progress.

28

III-l-S.

Spin Polarization of Residual Nucleus
in Heavy Ion Reaction

K. Ieki, M. Ishihara, T. Inamura, S. Kohmoto,H. Utsunomiya, K. Sueki, and H. Kudo

NUCLEAR REACTION 15~be~, <X")'), E = 115 MeV, 15~bCLi,

a'Y)]

E = :9 ~ev ; measured 'Y-ray circular polarization ; deduced spin[polanzatlon.

In the study of heavy-ion reaction mechanism, it is important to have information on the
angular momentum transfer to the residual nucleus and its spin orientation. Gamma rays emitted
from such an oriented nucleus are circularly polarized. The measurement of ')'-ray circularpolarization will, therefore, provide a useful probe into the reaction mechanism . This method
was first used for some few nucleon transfer reactions by Trautmann et al.l) We applied thismethod for fast light particle emission phenomena in 7Li-induced and 14N-induced reactions.
A 3.4 mg/cm 2 thick 159Tb foil was bombarded with a 115 MeV 14N beam and with a 49
MeV 7Li beam from the cyclotron. Alpha particles were measured with counter telescopes
consisting of 50 J.lm - 1500 J.lm Si detectors. Measurements were performed at four angles (20°,30°, 40°, 50°) for 159Tb + 14N and at 40° for 159Tb + 7Li with respect to the beam axis. At
forward angles an aluminum absorber of 140 J.lm thickness was used to avoid intense elastic
particles. Gamma-ray circular polarization was measured with two forward-scattering type
Compton polarimeters 2) placed perpendicularly to the reaction plane. A pair of telescopes anda pair of polarimeters were set symmetrically to the beam axis so that geometrical asymmetry canbe cancelled out using four coincidence pairs. 3) The magnetization direction of the polarimeter
(a)
~
C'\J
U
(/)

a.o
o

-'

(b)

1. 5

0.8
0.6

1.0

0.4

0.5

Q;

0.2

~
>,

ill

0.0

00

E
E

>,

-0.2~

- 0.5

-0.4

- 1.0

- 0.6
- 1.5

- 0.8
0

10

40
E~.LJ' H t\ ( MeV )

- 1.0
50

(a) The energy spectrum and (b)Fig. 1.
the ,),-ray circular polarization for the
159TbCLi, a) reaction. Emitted a particle
were measured at 40° to the beam.
Shaded area indicates a component fromtarget contamination.

29

was changed for each run to cancel out the spurious asymmetry which originated from an unequal
treatment of four coincidence pairs in electronic circuit. The spin polarization was deduced fromthe 'Y-ray circular polarization by assuming three statistical dipole 'Y transitions and a stretched
E2 'Y cascade. The sign of the spin polarization was defined by referring to the scattering normal

k j X kf .
In Fig. l, we show the results for the 159TbCLi,~) reaction. The energy spectrum (a) is wellcharacterized by a Gaussian distribution of ex-particle velocity centered at the beam velocity. The

(a )

(b )

Q)

<1:J
U
rJ)

a.o

ao
o

o

-.J

-.J
t---.,---'---.-----.-----,--~----I1.

1. 5
1.0

0

1---.---L....-...----~--.---__.__-_l1.

0.8

0.8

0.6 ~

1.0

0.6

0. 5

Q)

0.2 E

E

Q; 0.0 t----.....,..(',..,r""""F--:::----------l 0.0.f- 0. 2

- 0.5

~

0.4

0.4 C

0.5

0

l.5

0.2

N

Q,

E

0.0 I-----+-----~=r_......._t----i 0.0- 0.5-0.2 ~
«
-0.4
rJ)

- 0.4
-1.0

-0.6

- 1. 0

- 0.6

-1. 5

-0.8

- 1. 5

- 0.8

o

- l.0
60

0

!:-----:-.l:::----:::.I:::----:::-I::-----:-I::---::':::---;:J -

50

60

l. 0

E~.\f. H A ( MeV)

(c )

(d )
~

~

<1:J

<1:J

U

U

rJ)

rJ)

a.o

ao

0

0

-.J

-.J

1. 0
1.5
l.0

0.8

1.5

0.8

0.6 ~

l.0

0.6

0.4
0.5

0.2

N

Q,

0.0

~

-0.5
- 1. 0
- 1.5
0

10

20

30

0.4

C
Q)

E
E

0.0 ;;;
«
- 0.2
-0.4
- 0.6
-0.8
-1.0
60

0.5

0.2

N

Q,

c
Q)

E

0.0 t--------....~----r---__t--__t O.0 ~
«
- 0.2
-0.5
-0.4
-1.0
- 0.6
rJ)

- 0.8

-1.5

!:-----::~-::.l.:_-~-~----:l-::__----::l. -0E~.V.HA ( Me V)

Fig. 2.

~

10

60

1. 0

E~\f.HA ( MeV)

The energy spectrum and 'Y-ray circular polarization for the 159Tbe4N, ex)reaction at (a) 20°, (b) 300~ (c) 40°, (d) 50° (in laboratory angles). Shaded area
indicates ~ component from target contamination.

30

sign of the spin polarization (b) is negative for the beam velocity region and becomes positiveat higher energy region. The negative value of the polarization means that 0' particles are emitted
in the positive deflection angle. This can be interpreted as the result of a simple transfer reaction.
The positive polarization at the higher energy region is explained as a recoil effect in themassive transfer process. When energetic 0' particles are emitted, the residual nucleus receives thetangential momentum whose direction is opposite to that of the emitted particle. The tendencyof the measured polarization is well explained by taking into account the internal motion of
triton and 0' and the tangential velocity of the momentum at the nuclear surface.
In Fig. 2, we show the results for 0' particles from the 159Tb + 14N reaction. At the detection
angle of 40° the spin polarization is very similar to that of the 159Tb + 7Li reaction. But thesame explanation of energy dependence of spin polarization as was made in the Li case is notapplicable to this case. Since the transferred mass is larger, the needed internal energy becomeslarger, and the sign change must occur at 98 MeV of 0' particle energy. In the case of 14N induced
reaction, contributions from other reaction mechanisms must be considered. The sequential decayof emitted 8Be is known to contribute to the O'-emission channel considerably4): the proportionof 0' particle cross section due to the sequential decay of 8Be is less than 30 % at EO' ~ 40 MeV,
and becomes larger at higher energy. The recoil-effect calculation of (14N, 8Be) shows that the
spin polarization changes its sign at E8Be ::::, 80 MeV, i.e. EO' '::;: 40 MeV for the 8Be sequential
decay process. The spin polarization is negative for two processes for EO' < 40 MeV. At about
EO' = 40 MeV, two processes cancel out to result in zero polarization. At higher energy, thepositive component becomes predominant. Thus the observed spin polarization can be understoodby considering lOB and 6Li massive transfer processes.
At elab . = 50° (Fig. 2 (d)), the competition with the evaporation from the compound
nucleus occurs, reducing the spin polarization at lower energy region. At more forward angles (Fig.
2 (a),(b)), the spin polarization also has smaller values for smaller 0' particle energy. This fact
may be explained by the hot-spot picture as was proposed in the case of the proton polarization,5)
which shows positive polarization.
It may be possible to apply the hot spot picture to the positive polarization at the highenergy region. But it is difficult to explain the observed spin polarization and O'-energy spectra
simultaneously in terms of the hot-spot only.

References
1)

W. Trautmann, J. de Boer, W. Dunnweber, G. Graw, R. Kopp, C. Lauterbach, H. Puchta,2)
3)

and U. Lynen: Phys. Rev. Lett., 39, 1062 (1977).
K. Ieki and M. Ishihara: RIKEN Accel. Progr. Rep., 12, 119 (1981).
W. Trautmann, C. Lauterbach, J. de Boer, W. Dunnweber, G. Graw, W. Hamann,

4)

W. Hering, and H. Puchta: Nuc!. Instr. and Method, 184, 449 (1981).
H. Utsunomiya, T. Nomura, M. Ishihara, Y. Gono, T. Sugitate, K. Ieki, and S. Kohmoto:

5)

IPCR Cyclotron Progr. Rep., 14, 19 (1980).
T. Sugitate, T. Nomura, M. Ishihara, Y. Gono, H. Utsunomiya, K. Ieki, and S. Kohmoto:Nucl. Phys., A388, 402 (1982).

31

III-1-9.

Vector Analyzing
ReactionsPower Measurements for (d, p) and (p, d)

on Sn Isotopes and Deuteron D-state Effects

T. Kubo, H. Ohnuma, * T. Kishimoto, *M. Sugitani, ** and T. Suehiro***

NUCLEAR REACTIONS 116Sn(d, p) Ed = 55.4 MeV, llSsn(p, d)
Ep = 60.8 MeV; vector-polarized beams, measured da/dQ(O), Ay (0),J

[ DWBA analysis, deuteron D-state, enriched targets.

We have measured vector analyzing powers(Ay) and differential cross sections (da/dQ) for 116Sn (d, p) 117Sn
reaction at Ed = 55.4 MeV and llSsn(p, d) 117Sn reaction at Ep = 60.8 MeV, using vector-polarized deuteron andporton beams. It was expected to observe deuteron D-state effects on the vector analyzing powers in direct (d, p)and (p, d) reactions at relatively high incident energies.
The polarized beams were provided by an atomic-beam-type polarized ion source and accelerated by the AVF
cyclotron at RCNP (Research Center for Nuclear Physics, Osaka University). The beam polarization was
periodically reversed during data taking runs to reduce systematic errors, and was monitored by using a carbon
polarimeter placed before targets. The absolute value of the polarization was about 44 %, for deuterons and 82 %for protons . The targets used were self-supporting foils of enriched isotopes. Scattered particles were analyzed
by spectrograph RAIDEN and detected in a proportional counter system. Figure 1 shows examples of proton
spectrum from the (d, p) reaction and of deuteron spectrum from the (p, d) reaction. The overall energy resolution
was about 55 keV full width at half maximum. Experimental analyses were carried out for final states in 117Snthat were strongly excited and well resolved as seen in the spectra. The experimental results for the 1/2+ ground
116 Sn (d , p)117 Sn 55.4 MeV 30 deg .

5.a

0

•. 0

~
z

J. a

o
o
-.J
f-'
N

::0

a
u

f-'
•
f-'

o.

Ot--'
LTl-.J

+'"

2. a

f-'

1 .0

O. a

500

1000

1500

2000

CHA NNELSf-'

118 Sn (p,d)1l7 Sn 60.8 MeV 30 deg.
0~"I- •. a

'"z

.a

f-'

Ul

.J:)

'J1

W
f-' .......
'-...N

J. a

~

~+ 1+

2.0

0
0
•
0
-.JLTl

+

f-'
N:

0

w

-.J 0
"N
NO

f-'
-.J

+~

f-'
f-'

"

t--'
-.J

N

I

~

500

1000

'"
LTl

"+
N

1500

CHANNEL S* Department of Physics, Tokyo Institute of Technology.
* * Institute for Nuclear Study, University of Tokyo.
*** Department of Physics, Tohoku Institute of Technology.

Fig. 1.
Proton spectrum(upper) from the
116Sn(d, p) 117Sn reaction at 55.4 MeV and2000

deuteron spectrum(lower) from the118Sn(p, d) 117 Sn reaction at 60.8 MeV.

32

state(3s 1p), 3/2+ -state at 0.159 MeV(2d 3p), l1/2 - -state at 0.317 MeV(1h ll p), 7/2+ -state at 0.712 MeV(1g7p)
and 5/2+ -state at 1.179 MeV(2d sp) are shown in Figs. 2 and 3 together with those of calculations.
Exact-finite-range DWBA calculations were carried out by using the code DWUCK5 in which the deuteronD-state effects could be included. Distorting potential parameters used in the calculations are given in Table 1.
The proton parameters are those taken from reference 1 that reproduce the cross sections of elastic scattering of
61.4 MeV proton on 116Sn . The deuteron parameters are of so-called adiabatic potential with which contributions
from deuteron break-up channel to (d, p) and (p, d) reactions can be approximately involved. Following theformula of Harvey & Johnson,2) we constructed the adiabatic potential from the neutron and proton potentials of
Becchetti & Greenlees. 3) Non-locality corrections for these distorting potentials were included in local energy
approximation. The Reid soft core potential4) was used for the n- p interaction(V n-p) to describe the transferof neutron as well as to generate the deuteron internal wave functions. The form factor of the transfered neutron
was made with usual sepraration energy method. The results of the calculations with and without the D-state
effects are shown in Fig. 2 for the cross sections and in Fig. 3 for the analyzing powers. The cross sections
calculated were normalized to those measured at forward angles.
The cross sections are, on the whole, well reproduced by the calculation except for the 2d s/2-state in the(d, p) reaction and the Ih u /2- and Ig7/2-states in the (p, d) reaction which are somewhat poorly reproduced at
backward angles. On the other hand, the analyzing powers are very poorly reproduced except for 1n = 0transitions to the 3s 1/2-state(ground state). The reproduction of the In = 0 transitions is fair to examine theD-state effects, although it is a little poor at forward angles where calculated curves are slightly shifted in theforward direction in comparison to the experimental data.
The calculations of the cross sections are found not much affected by the inclusion of the deuteron D-state
effects. The D-state effects only slightly increase the intensity around minima. However, large D-state effects
can be seen in the results of the analyzing powers in comparison with those of the cross sections. The reproduction

11 8 Sn (P,d) 117 sn 60.8NeV

-

S +D

--- S
116 Sn (d , p)1l7 sn 55 . 4MeV

10 '

10'

Fig. 2.
Cross sections for the 116Sn(d, p)
117 Sn(left) and 118Sn(p, d)1l7Sn(right) reactions

1 .179 5/2+~

compared with the calculations with(solid line))060

eM - ANGLE (DEG)

90

and without(dashed line) the D-state effects.

33

Ay

11 6S n (d , p ) 1 17 S n 55 . 4 MeV_ ... --,,••• •{.--.-;, •• +.
+.;\ .

_<"7."-",,,...--o--~••~~0.15 9 3 / 2+

0 . 317 11 / 2• +, +.

0 .71 2 7/ 2+.. \ ·.'H'.' +- 0. 5~0.5

o CF~~:<-~-'7----------1
1.1 79 5 / 2+

- 0.5

o

60

30

118 Sn (P , d )117 S n 6 0. 8 Me V
90oCM-A NGLE WEG)

Fig. 3.

S +D- -- 5

'0·5

S+D
--- 5

30

60

90

CM -ANGL E WEG )Vector analyzing powers for the 116Sn(d, p) 1I7Sn(1eft) and 1I8Sn(p, d) 1I7 Sn(right)

reactions compared with the calculations with (solid line) and without( dashed line) theD-state effects.

Table 1. Distorting potential parameters.

w
Deuteron

95.18

l.17

0.75

8.94

9.80

1.29

0.60

6.20

1.01

0.75

1.25

Proton41.93

1.179 0.687

3.80

5.10

1.24

0.808

6.11

1.057

0.80

1.25

34

of the In = 0 transitions is found much improved around positive peaks for the (d, p) ractions and aroundnegative peaks for the (p, d) reaction with the inclusion of the D-state effects. It may not be adequate to examine
the D-state effects on the analyzing powers of the other transitions, since they are very poorly reproduced andthe D-state effects do not necessarily improve their reproduction. However, if we see only the results of thecalculations, we can see the large D-state effects. The calculations on the 2d 3f2-, Ih l1 ,12-' and 2d s,I2-states in the(d, p) reaction and the Ih ll ,l2-state in the (p, d) reaction are much affected.
For comparison, we tried DWBA calculation using a deuteron distorting potential that reproduces the elastic
scattering. T~is calculation gave very poor results for the cross sections as well as the analyzing powers.
We failed to reproduce consistently the experimental data by the calculations including the deuteron D-state
effects. However, the large D-state effects were observed for the analyzing powers. Especially, the fit of the
In = 0 transitions were much improved. More detailed analyses are in progress.

References
1)

G. B. Fulmer, 1. B. Ball, A. Scott, and M. L. Whiten: Phys. Rev., ~, 1565 (1969).

2)

J. D. Harvey and R. C. Johnson: ibid., C3, 636 (1971).

3)

F. D. Becchetti and G. W. Greenlees: ibid., 182, 1190 (1969).

4)

R. V. Reid: Ann. Phys. (NY), 50, 411 (1968).

35

III - 1 - 1 O.

Excitation Modes of the r-band in 24Mg throughthe 24Mg(p, p') Reaction

M. Sugitar..:,* T. Hasegawa,* S. Kubono,* Y. Ishizaki,*K. Iwatani,** and T. Fujisawa

J

NUCLEAR REACTIONS, 24Mg(p, p') E = 29.3 and( 40.3 MeV; measured cross section and analyzing power.

Coupled channel analyses with the symmetric rotator model gave a great success in the study of inelastic
excitation of ground rotational bands (GRB) of deformed nuclei. On the other hand, excitation modes of side
bands had been scarcely investigated. In recent years, the ')'-band of 24Mg, the band head of which IS the 2; state
at 4.24 MeV, was investigated by proton inelastic scattering at various energies. 1),2) As a result, excitation modesof the GRB could be explained by ordinary coupled channel analyses (CC) using the symmetric rotator model.
However, the cross sections of the members of the ,-band could not be reproduced by the CC calculations using
the asymmetric rotator model, mainly the Davydov-Filipov model 3) (D - F model). In this reaction, it is expectedthat polarization phenomena reflect delicate shades of the nuclear structure and the reaction mechanisms. We
measured analyzing powers and cross sections of the 24Mg(p, p') reaction and performed the second-order distorted
wave Born approximation (DWBA) analyses with the shell model description, which improves the defects of theD-F model.
The experiment was performed with 29.3 and 40.3 MeV polarized proton beams obtained from the SF
cyclotron with a polarized ion source 4) made by the RIKEN staff at INS, University of Tokyo. A self-supporting
enriched (> 98 %) metalic 24Mg target was used. The thickness of the target was 0.34 mg/cm 2 and contaminationof oxygen was less than 2 % in weight. The beam intensity on the target was about 30 nA and the polarization
was about 50 %. A polarimeter, installed just in front of the scattering chamber for the quadrupole-dipole-dipole(QDD) magnetic spectrograph, monitored protons scattered elastically by a 12C target using surface-barrier silicondetectors 2 mm in thickness and aluminum absorbers 2 mm and 5 mm in thickness for the 29.3 and 40.3 MeV
experiment, respectively. The sign of polarization was changed at a beam amount of every 0.6 J.1 Coulomb.
The absolute value of polarization was determined from the data of the double-scattering measurements,5),6) andits error was less than 10 %. Difference of the polarization between an up-spin beam and a down-spin one wasless than 3 % throughout the experiment. Particles scattered by the 24Mg target were momentum analyzed by
the QDD magnetic spectrograph and detected with a drift-type position-sensitive single wire proportional counter(80 - III ),7) placed on the focal plane of the spectrograph. The effective range of the detection of the counter is
80 cm long. Particle identification was made with two signals: energy losses from a L'-.E counter located behindthe position-sensitive wires in the 80 - III counter and energy signals from a plastic scintillator 10 mm thick and100 cm long installed just behind the 80 - III counter. The energy resolution was about 70 keV mainly due to a
spread of the beam energy and the beam profile on the target. The experimental results of the ,-band are shownin Figs. 1 and 2 with the analyzing power data of E~p = 20.3 MeV. 8) The error of the absolute cross section isabout 20 %.
The cross section data show normal behaviors for all the levels of the ,-band in the sense of kinematicalunderstanding, and the analyzing power data of theandstates are also normal, where the bottom and top
peaks are getting smaller as the incident beam energy becomes higher. However, the energy correlation among2;

4;

20.3, 29.3, and 40.3 MeV can be hardly found in the analyzing powers of the 3: state. This characteristic is not* Institute for Nuclear Study, University of Tokyo.
** Department of Engineering, Hiroshima University.

36

10°

24

••• •
••• •••

~

I

-29.3

2;

•

,

-.a.

Mg (P I P ) Ep =. 20.3MeV

22+.
-40.3 tEx=4.24Me~++
Or---~+~·~------Trl~~--~

0.5

10°

+

••

Ex =4.24 MeV

en

..0

E
c:

o

....o
Q)

en
en
en

o

"-

()

10

-\

,o-J~i:::1aaa: •••••....c:
Q)

"-

Q)

c

+
42

I

~

(1)

:t

o
c..

0.5

. ....... •Ex=6.01 MeV

"'\

...
4+ Ex =6.01 MeV...... • • .....
2•••• •••• •

...

•

...

..

....... 4 . . . . "

.....

•
•

•

Sc.rn.
Fig. 1.

The angular distributions

Fig. 2.

Sc.m.
The angular distributions ofof the differential cross sections of thethe analyzing powers of the -y-band-y-band in the 24Mg(p, p') reaction at

at the energies of 20.3 8), 29.3, andthe incident proton energies of 29.3

40.3 MeV. The curves are the sameand 40.3 MeV. The curves show theas those of Fig. 1 for analyzing powers.

results of the second-order DWBA
calculation induding the (p-p"-p')prosesses via the

27 and 2; states andthe (p-d-p') processes.
found in the cross section data.
In the analyses, the two-step processes as (p-p'~p') and (p-d-p'), are also calculated for the2;, 37, and 4;

states besides the direct one-step processes. Intermediate states, we choose for two-step processes, are the

27 and2+ states of 24Mg for the (p-p"-p') process and the 3/2+ (ground state) and 5/2+ (Ex = 0.47 MeV) states of 2\1g forthe (p-d-p') process, because effects of other states are quite small. The results of the calculation are shown in
Figs. 1 and 2. The cross section of the

37 state is roughly reproduced by this calculation. The difference of37

analyzing powers of the 3: state between the data of Ep = 29.3 and 40.3 MeV could be explained by energy
dependence of the analyzing powers of the (p-d-p') processes. Although the failure of the CC calculation was
attributed to the defects of the D- F model, the shell model description leads to proper cross sections. It is
indicated that excitation of the 3: state would occur through ordinary couplings, because the coupling strengths
between the 3: state and the two 2+ states are quite large. The cross section of the 4; state was underestimatedby a factor of about 5 in the forward angles, even when the second order DWBA was included. The direct
excitation from the ground state might be most components of this transition due to a hexadecapole deformationof 24Mg,2) although the shell model calculation provides small values for the E4 transitions. 9) The remaining
problem concerns this point and the inelastic excitation mechanisms of 24Mg would be brought up to light byfurther discussions on the data of the analyzing powers.

References
I)

3)
4)
5)

J. Eenma, R. K. Cole, C. N. Waddell, H. S. Sandhu, and R. R. Ditman: Nucl. Phys., A218, 125 (1974);
I. Lovas, M. Rogge, U. Schwinn, P. Turek, D. Ingham, and C. Mayer-Boerick: ibid., A286, 12 (1977);
R. M. Lombard, J. L. Escudie, and M. Soyeur: Phys. Rev. C, .lli., 42 (1978); R. de Leo, G. d'Erasmo,
E. M. Fiore, A. Pantaleo, M. Pignanelli, and H. V. Geramb: ibid., 20, 13 (1979).
R. de Leo, G. d'Erasmo, A. Pantaleo, M. N. Harakeh, S. Micheletti, and M. Pignanelli: Phys. Rev. C, 23,1355 (1981).
A. S. Davydov and G. F. Filipov: Nucl. Phys.,.§.., 237 (1958).
T. Fujisawa, S. Motonaga, N. Ueda, S. Yamada, and T. Hasegawa: AlP Conf. Proc. No. 69, p. 906 (1980).
R. M. Graig, J. C. Dore, G. W. Greenlee'S, J. Love, and D. L. Watson: Nucl. Phys., 83, 493 (1966); ibid.,

6)
7)
8)

79, 177 (1966).
L. N. Blumberg, E. E. Gross, A. van der Woude, A. Zucher, and R. H. Bassel: Phys. Rev., 147,812 (1966).
M. H. Tanaka, S. Kubono, S. Kato: Nucl. Instr. Meth., 195, 509 (1982).
A. S. Blair, G. Glashausser, R. de Swiniarski, J. Goudergues, R. M. Lombard, B. Mayer, J. Thirion, and9)P. Vaganov: Phys. Rev. C, 1,444 (1970).
B. A. Brown, W. Chung, and B. H. Wildenthal: ibid.,2)n, 2600 (1980).

38

III -1-11.

Multiple Coulomb Excitation of 167Er

T. Inamura, A. Hashizume,
M. Ohshima, * E. Minehara, * and M. Ishii *NUCLEAR REACTIONS 167EresCl 3SCl', r), E = 160 MeV; measured]
E , I (8), rr coin., rrDCO, lifetimes ; deduced levels, J, 1T, r branching,r r[ 8(E2/M1), B(Ml), B(E2).

It is well known that high- j orbits such as i 13(2 cause strong perturbation to the rotational bands ofdeformed odd-mass nuclei. However, interweaving of rotational and intrinsic motion is still to be studied
quantitatively by measuring not only level energies but also transition moments of the band members. Recently,
Hamamoto has made a cranking model calculation and demonstrated that even if the rotational frequency isrelatively small, the perturbation effect of rotation on M1 and E2 transitions becomes quite large in the case of
the odd-mass nuclei with the i 13(2- neutron orbit. 1) It is of value to examine whether such a rotational
perturbation is really appreciable.
We carried out mUltiple Coulomb-excitation experiment on 167Er whose ground-state rotational band is built
on the i 13(2-neutron orbit, i.e., 7/2[633]. A self-supporting metallic target of 167Er (91.5 % enriched and about

80 mg/cm 2 thick) was bombarded with a 160 MeV 3sC1 beam from the 20 - UR tandem accelerator at Japan

Atomic Energy Research Institute. We measured angular distributions of de excitation r rays , r - r coincidences,r - r directional correlations (DCO), and lifetimes of excited states in 167Er. The lifetimes were determinedfrom Doppler broadened r-ray lineshapes. The technique was the same as described in Ref. 2.
The ground-state rotational band of 167Er has been established up to the member with spin 25/2. Higher
spin states, 19/2+ at 772.75 ± 0.03 keY, 21/2+ at 954.95 ± 0.05 keY, 23/2+ at 1195.3 ± 0.1 keY, and 25/2 +at 1394 ± 1 ke V, were newly identified. In Table 1 are summarized the observed properties of r transitions in
the ground-state rotational band.
As is shown in Fig. 1, the reduced transition probabilities of crossover E2 transitions B (E2 ; I ---+ 1-2)
have turned out to be very close to the rigid rotor predictions (Q o = 7.5 e b was used, which was estimatedfrom the B (E2 ; 7/2 ---+ 11/2) value adopted in Nuclear Data Sheets. 3) It is, however, interesting to note that
there seems to exist such a selection rule that B (E2) values between excited states labelled by the signature 1),4)
r = + i are reduced slightly as compared with those between neighbouring excited states with the signaturer = - i, i.e. B (E2; (I, r = + i) ---+ (1- 2, r = + i)) < B (E2; (I, r = - i) ---+ (I - 2, r = - i». This appears to coincidewith the prediction made by Hamamoto.I)
In Fig. 2 the reduced M I-transition probabilities of stopover transitions B (M 1; I ---+ 1- 1) are plotted as afunction of initial spins I and compared to the rigid rotor predictions (gk - gR = - 0.57 was used, which is given
in Ref. 5). Experimental B (M 1) values are considerably smaller than the rigid rotor predictions, and they showthat when the initial state has the signature r = + i, the Ml-transition strength is reduced as compared with thatof neighbouring excited states with the signature r = - i, i.e. B (M I; (I, r = + i) ---+ (1 - 1, r = - i» < B (M 1 ;(I, r = - i) ---+ (I- I, r = + i). This signature dependence of M I-transition probability is also theoretically pointed
out as the perturbation effect of rotation by Hamamoto. I )It is of particular interest to study whether the observed transition probabilities are reproduced consistently
in a framework that accounts for the attenuation of the Coriolis interaction which is introduced in making
Coriolis band -mixing calculations to fit level energies. 6)* Japan Atomic L~ nergy Research Institute at Tokai.

39

Table 1. Summary of')' transitions in the 7/2+ [633] ground-state rotational band of 16~r., Mixing ratios
8(E2/M1) are' the weighted averages of the values deduced from A2 and A4 and DCO ratios. Numbers
in parentheses -indicate the uncertainties in the least significant figure.
Initial spin
J1T

Lifetime

Transition a)

(ps)

(KeY)

9/2+

119 (9)b)

11/2+

59 (6)b)13/2+

42 (8)

15/2+

32 (4)

17/2+

16 (2)

19/2+

10 (2)

21/2+

5 (1)

23/2+

3.5 (7)

25/2+

-----

Relative intensity

Ang. distr. coefficients

I')'

IT

79.33 (1)563 (56)

3840 (380)98.62(1)

305(31)1240 (120) - 0.038 (12)117.98 (1)100 (5)138 (7)116.99(1)88 (9)

250 (25)- 0.195 (22)215.63 (1)76 (4)

90 (5)

0.0776 (38)139.50 (1)37 (4)

78 (8)- 0.245 (13)256.47(1)60 (3)

66 (3)

0.110 (4)152.93(1)13 (1)

24 (2)- 0.303 (9)292.42 (1)36 (18)38 (2)

0 .1 44 (4)185.3(2)2.9 (5)4.3 (7)338.24 (1)

17 (1)

18 (2)

182.3(2)

1.3 (2)2.0 (3)367.62 (4)5.7 (6)5.9 (6)241.4 (5)0.56 (6)0.69 (7)421.5 (1)2.3 (3)2.4 (3)A2

A4

Mixing ratioo(E2/M1)

0.031 (54) - 0.45 (11)0.0176 (39) - 0.001 (6)0.002 (30) - 0.23 (11)0.012 (6)0.028 (18) - 0.25 (6)0.015 (5)- 0.039 (12) - 0.31 (8)- 0.017 (5)- 0.35 (15)0.139 (4)- 0.013 (5)- 0.15 (45)0.121 (15) - 0.010 (20)
- 0.20 (10)0.298 (37) - 0.009 (45)439 (1)a) Transitions whose mixing ratios are given in the last column are stopover (Ml + E2) transitions;otherwise they are crossover E2 transitions.
b) Cited from Nuclear Data Sheets. 3)

167 Er';:;Rigid rotor( 9' -</11 =- 0,57\

N

~

i

-.
,.

N~

1. 5

;:: 0,4

N

I

W

-.

CiS
...... 1 0 1N
I
-.

i
~

! 0,5 1-

0.2

~

:::::

N

W

CiS
II'"

13 -

15 ~

2"

2

2

1]+

/" 2

19+

21 +

23'

2

2

2

Fig. 1.
Crossover E2-transition
probabilities in the 7/2+ [633] groundstate rotational band of 167Er. The
B(E2) values are plotted in units of therigid rotor estimates (Qo = 7.5 e b).

Fig. 2.
MI-transition probabilities
in the 7/2+ [633] ground-state rotationalband of 167Er. The R(M 1) values areplotted in units of P N 2. The solid line
indicates the rigid rotor estimates(gk - gR = - 0.57).

40

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

I. Hamamoto: Phys. Lett., 102B, 225 (1981); 106B, 281 (1981).
T. Inamura, F. Kearns, and J.C. Lisle: Nucl. Instr. and Meth., 123 , 529 (1975).
B. Harmatz: Nuclear Data Sheets, 11, 143 (1976).
I. Hamamoto and H. Sagawa : Nucl. Phys., A327, 99 (1979).
A. Bohr and B.R. Mottelson: Nuclear Structure,l, (J/.A. Benjamin, Inc.) , p. 303 (1975).
See, for example , S.A. Hjorth, A. Johnson, and G. Ehrling: NucL Phys., A184, 113 (1972).

41

III -1-12.

Excited States in 157 Yb and 158Yb

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

NUCLEAR REACTION 144,147'S m

ct60, xn"Y), E = 80 - 120 Mev;]

142Nde<Ne, xn'Y), E = 125 MeV, measured E"Y' tyCO), "Y"Y-coin.
[ 157,158yb deduced levels. Enriched targets Ge(Li) detectors.

The nucleus 158Yb has 88 neutrons and is expected to have a level structure of nuclei intransitional region, making a contrast to the structure of 160Yb which is well deformed. Using
147Sm(160, 5n) and 142Nde~e, 4n) reactions, we have previously excited 158Yb nucleus, and byobserving de-exciting 'Y-rays, revealed the existence of the excited states up to (16+).1) In view of
the characteristic features of energy levels of transitional nuclei, it is also important to study theside band structures. We have continued to analyze 'Y..rr coincidence data and obtained 384, 453,
499, 531, and 592 ke V 'Y-rays which were assigned to the side band transitions. When the
coincident gate was opened by 782 keY 'Y-ray, the coincidences of above mentioned 'Y-rays exceptthat of 592 keY were observed. These results were interpreted tentatively as due to the( 16 - )---,---II
I

I

14 -'- I 4 164

4055
531

12-

3482

3524
499

10 +

2748

3025
384
2641

;; 1. 0 , - - --453 (2 9/ 2 + )
2 188

2 300 + X---,-----,------r-----,(j)!" .__.~,N ~87'"--'" 0 5...L ""' ..... ,~(2 1/2+)1034+X

~

,,

,

(j)

c
(j)

-'-.
4 _+ +-- 835.9

co( 17/_2_+--;) 1--_491 + X___
2_+-+--- 358.8
0+--L...- O
158(13/2-1-)o6~2--~~--~---~--~70

-~- x

z

Yb

(a )

(b )

Fig. 1.
Excited states in 158Yb
and 157Yb.

Fig. 2 .

A systematics of energy

differences between 7/2 - and 13/2+
states of N = 87 nuclei.

42transitions of 592, 453, and 782 keV between the states shown in Fig. 1. The experimental
results of coincidences between 'Y-rays in the ground state band were also taken into accounts.
Other levels in the side band are those based on the 2641 MeV level.
The energies of the levels in the ground state band up to 10+ state of 158Yb were interpretedby IBM (Interacting Boson Model) employing 3 neutron pairs and 6 proton pairs. The main partsof wave function are composed of up to 6 d-bosons for 10+ states.
Excited states in 157Yb have been investigated for the first time by measuring excitation
functions, n-')' coincidences, 1'-')' concidences and angular distributions. 2) We continued toanalyze the experimental results a'nd found that 674 keV E2 'Y-ray is also a member of yrast bandtransitions as shown in Fig. 1(b).
The level structures of nuclei of N = 87 isotones in this region have been studied up to
Z = 68. The level energy systematics between f7/2 and i13/2 states 3) are shown in Fig. 2. As shownin the figure, energies of 13/2+ states relative to those of 7/2- states decrease as Z numbers
increase. It is expected that the 7/2- and 13/2+ states lie very close in energy at Z = 70. For
this reason the yrast band observed is supposed to be that built on 13/2+ state. However, it is
not clear if the 13/2+ level is the ground state. To investigate this situation an experiment toobserve conversion electrons from short lifetime states is in progress.

References
1)

A. Hashizume, T. Katou, Y. Tendow, and H. Kumagai: IPCR Cyclotron Progr. Rep., 14,
59 (1980).

2)

A. Hashizume, T. Katou, Y. Tendow, and H. Kumagai: RIKEN Accel. Progr. Rep., U, 54(1981).

3)

C.M. Lederer and V.S. Shirley: 'Table of Isotopes', John Wiley & Sons, Inc. (1978); J. Jansen,
M. De Voigt, Z. Sujkowski, and D. Chmielewska: Nucl. Phys., A321, 365 (1979); P. Ager,
G. Bastain, G.P. Tibeau, D. Barneau, G. Boute, and K. Fuan: Izv. Akad, Nauk SSSR Ser. Fiz.,11, 1992 (1977).

43

III-1-13.

Analysis of Gamma-Ray Mul.tiplicity Distributions for the

159TbC4N, axn} Reaction at 115 MeV*

T. Inamura

NUCLEAR REACTIONS 159Tbct4N, Qxn)169-x yb
E = 115 MeV; massive transfer; ,·ray averagej[ multiplicity, variance, skewness.

)

Massive transfer is a type of heavy-ion reactions in which a massive fragment of the projectile
is transferred to the target nucleus and energetic fragments such as protons or a particles are
emitted in the forward direction. 1) Since the reaction is considered to occur for a narrow range
of entrance-channel angular momenta (f window), it is interesting to study how the associated,),-ray multiplicity distribution reflects the existence of such an f window: the ,),-ray multiplicity
distribution is affected by the way of populating the entry states, i.e. the excited states prior to')' decay.
Table 1 summarizes the results of analyses of ,),-ray multiplicity distributions for the
159Tb(14N, axn)169- xYb reaction at 115 MeV. (Alpha particles of energies larger than 22 MeV
in the laboratory system were recorded at 12.3° to the beam.) The a5n channel, which was themost intensive in those reactions, is one of typical examples of massive transfer. 1) What arecharacteristic of this channel are as follows: (1) The average ')'-ray multiplicity < M > isindependent of yrast spin values; (2) The sign of skewness sM is likely to be positive.
The second feature supports the conclusion of a statistical calculation made for this reaction
by assuming a spin localization in the entry state population. 2) This calculation predicts the first
feature as well. This feature has also been observed in other reactions that are probably considered
as massive transfer. 3)
As is seen from Table I, these features are also remarkable in the cases of a3n and a4nchannels, while the a6n channel is different. In the a6n channel < M > increases with spinvalues, and the sign of skewness is likely to be negative. These properties are characteristic ofcomplete fusion reactions. 2)' 4)
It is interesting to note that even in the a5n channel < M > increases with spin values I when

it is measured by gating at low-energy a particles (see Fig. I). For a particles of energies larger
than 30 MeV, < M > becomes independent of I as is seen in integrating over Ea above 22 MeV.
Therefore, it may be said that the fast component of a particles which dominates the a5n channel
originates from massive transfer, and the slow component is associated with complete fusion.
The most probable a-particle energy for the a5n channel in the present case is about 28 MeV.
As for the width (variance) aM' it is hard at present to extract something characteristic ofmassive transfer, compared with complete fusion.

* Experiment was carried out in collaboration with A.C. Kahler, D.R. Zolnowski, U. Garg, and T.T. Sugihara at the Cyclotron
Institute, Texas A & M University.

44

Table 1. ,),-ray multiplicity distribution parameters for yrast transitions observed in the
159Tb(14N, Qxn) 169-xYb reaction at 115 MeV. Numbers in parentheses
indicate the statistical uncertainties in the least significant figure.
Final
nucleus
166 YbTransition

<M>

aM

4+ - 2+

10.2 (6)5.0 (8)6+ - 4+11.0 (5)6.1 (10)+1.0(11)8+ - 6+10.8 (5)6.8 (9)+2.0 (18)12+ - 10+10.8 (9)5.1 (14)

14+-12+10.0 (20)17/2+ - 13/2+

11.5 (6)5.6(10)+1.8(11)

21/2+ - 17/2+

10.8 (6)4.4 (14)+2.0 (27)25/2+ - 21/2+

10.7 (5)4.7(11)+2.8 (24)29/2+ - 25/2+

11.9 (9)5.1 (16)+0.9 (27)4+ - 2+13.9(3)6.2 (5)+ 1.9 (7)6+ - 4+13.9(3)

6.8 (6)+0.6 (5)8+ - 6+13.9 (2)5.1 (6)+0.1 (12)10+ - 8+14.5 (3)4.5 (7)+0.4 (.15)

12+ - 10+14.3 (4)5.1 (9)+0.5 (17)14+ - 12+13.6(6)

4.2 (16)+ 1.8 (39)16+ - 14+13.5(6)4.6 (14)

17/2+ - 13/2+

11.4 (9)8.0 (12)

21/2+ - 17/2+

11.8 (6)7.0 (13)- 0.3 (11)25/2+ - 21/2+

12.3 (3)5.3 (9)-0.4 (11)29/2+ - 25/2+

10.8 (16)

3.9 (28)

33/2+ - 29/2+

13.6(20)

4.3 (27)

37/2+ - 33/2+

14.7 (42)sM

10+ - 8+

165Yb

164Yb

163Yb

45

15

-I-l-!

22~ EaI I

I 22 ~ Ea ~ 25

A.

~

15

I

x

20

'-/

!

-i/x x

4~-:I

r~Ear

JI iI~:::~35
MeV

10

Fig. 1.
< M > vs. yrast state with spin
I through which the 'Y-cascade has to go in
the 15~be4N, a5n)164Yb reaction at
115 MeV. Alpha particle energy bin isindicated on the right.

References
1)
2)
3)

T.T. Sugihara: Physica Scripta, 24, 108 (1981), and references therein.
T. Inamura and M. Wakai: J. Phys. Soc. Japan, 21, 1 (1982).
H. Yamada, C.F. Maguire, J.H. Hamilton, A.V. Ramaya, D.C. Hensley, M.L. Halbert,

4)

R.L. Robinson, and F.E. Bertrand: Phys. Rev. C, 24,2565 (1981).
G.B. Hagemann, R. Broda, B. Herskind, M. Ishihara, and S. Ogaza: Nucl. Phys., A245, 166(1975).

46

III-1-14.

level Scheme of 217Ra

M. Sugawara, Y. Gono, Y. Itoh,T. Kubo, and T. Nomura

NUCLEAR REACTION 2oSpb( 13C, 4n), E = 80
[

Mev;]

measured E'Y' I'Y' 'Y'Y-coin, a'Y-coin; 217Ra deduced
levels, J, 1T, T 1/2.

Level scheme of 217Ra was studied by in-beam spectroscopic techniques. In this nucleus only
two excited states are known from the a-decay study of 221Th(Ref. 1). The a-decay of the groundstate in 217Ra is also known. The energy of the a-decay is 8.990 MeV and the half-life is 1.6 /lS(Ref. 1).
Measurements of a-"'{ coincidence, "'{-"'{ coincidence, ",{-ray angular distribution and "'{-raytiming with respect to the beam bursts were performed using the 208Pb(13C, 4n)217Ra reaction at
E = 80 MeV. The "'{-rays which belong to the 217Ra nucleus were identified in the coincidence "'{-rayspectrum gated on the 8.990 MeV a-line which is shown in Fig. 1. The "'{-"i coincidence spectra
obtained by gating on 540 and 330 keY "'{-rays which appear strongly in the above mentioneda-"'{ coincidence spectrum is shown in Fig.

2. Figure 3 shows a tentative level scheme of 217Ra

which was constructed using the "'{-"'{ coincidence and "'{-ray angular distribution data. Twoparallel bands were observed. One band consists of the dipole cascade transitions with thequadrupole cross-over transitions between the 540 and 1455 keY levels. This band structure issomewhat similar to that in the 218Ra nUcleus. 2) An isomeric state with a half-life of 6.5 ns wasfound at the excitation energy of 2301 ke V. The 330 and 737 ke V levels seem to correspond to
the previous 1" known 331 and 756 keY levels. 1) Further analysis is in progress.
DelayedAlpha
214 Rn9,04 MeV'~: -t·~ ")~'}, ""
~

(

\:

11~;\\\Jf1
10--'- I ~~

400

r'l
-~--

j" ~~-- _. _- - ,

500

o

<;t

LO

20
if)

I-

Z10

:::J

o
U

o

1000

2000

CHANNEL

Fig. 1. Gamma-ray spectrum obtained by gating on 8.990 MeV
a-line of the ground state decay in 217Ra.

47

600 -

o
o

<D

Vl

I-

z

8200
1000

2000

CHANN EL

Fig. 2.

Gamma-gamma coincidence spectra: the upper one is

obtained by setting gate on 540 keY and the lower one on
330 keY gamma-rays.

3897
3537
N

......

ev)

3240

3165
~
-s

'"'co

2539

2301
2072

1337

( fl )
2

N

to

-s

0
0

c'

to

737
330
0

r')

( !2+)

2( 11+)

2

(~)

tV I

'?

If)

-s

......

c--

~

~

'3

)'

..

( '2 ) 1455(~ ) )329
17+

(2)

-

993

(.!2) 8212+(1f) 540

0

~

-s

If)

2

217R
88

a 129

Fig. 3 .
A proposed level
scheme of 217Ra.

References
1)

Table of Isotopes, 7th edition , (ed. C.M. Lederer and V.S. Shirly), John Wiley , New York(1978); and Nucl. Data Sheets, 28, No.4 (1979).

2)

Y. Itoh , Y. Gono , M. Sasagase, T. Kubo, M. Sugawara, S. Hayashibe, T. Kono,
and T. Nomura: p. 48 in this report.

48

III - 1 - 1 5.

Level Schemes of

216.218 Ra

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

NUCLEAR REACTIONS 20Spbe2c, 4n), E = 80 MeV, 2oSpb( 13C, 3n),(13C, 5n), E = 65 - 95 MeV; measured E'Y' 11'(8), 1'Y(t) , I'Y(E), ICC,
1'-1' coin., cx-'Y coin., 216, 218Ra deduced levels. Ge(U) and LEPS
detectors, enriched target.

We have studied excited states in 216, 218 Ra by means of in-beam a- and 'Y-ray spectroscopic
techniques using 12, 13C beams provided by the cyclotron. The levels in 216Ra are extended tohigher spin states than those in the previous report. 1)(1) 216Ra
Levels in 216Ra were constructed up to the 11- state by Nomura et al.l) at first and extended
recently up to the 14+ level by Chevallier et al. 2)
Adding to our previous work on 216Ra, we carried out an internal conversion electron andextended 'Y~ coincidence measurements. The internal conversion electrons were measured withthe 208Pbcr2c, 4n) reaction by using a mini-orange electron spectrometer with a cooled Si(Li)detector. The analysis of the conversion electron data confirmed that 399 keY and 557 keYtransitions are both M 1 + E2 type ones. In this analysis we used as calibration the internalconversion coefficients 1) of the 344 keY, 476 keY, and 688 keY transitions which are of E2
character.l) The 'Y~ coincidence measurement with two Ge(Li) detectors located at () = ±90°
was performed using the 208Pb( 13C, 5n) 216 Ra reaction at E = 95 MeV. This reaction was expected
to populate higher spin states in 216Ra than the reactions used in our previous work. 1) The
delayed coincidence spectra among 'Y-rays in 216Ra suggested that at least two isomers exist.
Because of the existence of two isomers, the delayed 'Y-ray coincidence spectrum can beeffectively used to construct the high spin states in 216Ra. The level scheme obtained is shownin Fig. l. The level energies of two isomers were identified to be 3.76 MeV and 5.l7 MeV, forwhich the half-lives were deduced to be 6.0 ± 0.4 ns and 6.7 ± 0.6 ns, respectively, from the'Y-ray time spectra. Parallel cascade transitions of 199 keY - 221 keY and 290 keY - 130 keY
were found as transitions below the first isomer. As previously reported,1) we also found a
51 keY transition of E 1 character. On the basis of the 'Y-rays' time spectra of this transition, we
put the 51 keY transition below the first isomer. These results confirmed the level scheme of216Ra under the 19- state as shown in Fig. l. We observed 110 keY and 120 keY 'Y-rays
presumably between the 14+ state and the 19- isomer. But we could not make them participate
in the level scheme. Between the first and second isomers, four 'Y-rays were found to be incascade. Their ordering was determined according to their transition intensities. Since the* Hitachi Computer Engineering.
** Faculty of Science, Tokyo Institute of Technology.

49

multipolarity of 194 keV transition could not be determined , the spin-parity assignments of the

5.17 MeV state and states above it remain ambiguous.
The energy compression near the 19- isomer and the isomerism of the 19- and 25- states canbe understood 3) in terms of the couplings of two valence neutrons to the excited states in 214Ra(Ref. 4).
218Ra

(2)

The level scheme of 218Ra was reported by two groups.5) In those reports the negative parity
band as well as the ground state band were presented, and Fernandez-Niello et a1. 5) concluded thatthe negative parity band is probably an octupole vibrational band.
In addition to the standard in-beam 'Y-ray spectroscopy, cx~ coincidence measurements on
218Ra were carried out using the 208Pb( 13C, 3n) 218 Ra reaction at E = 70 MeV. The 'Y-rays which
belong to 218Ra were identified by the cx~ coincidence measurement setting a gate on the ex-lineof the ground state decay of 218Ra (Ecx = 8 .39 MeV , T 1/2 = 14 Jls(Ref. 6)). Time spectra of'Y-rays with respect to RF signals of the cyclotron which were taken by a 70 cm 3 Ge(Li) detector
had no delayed component longer than T 1/2 = 2 ns. This limit of T 1/2 is given by referring to theslope of the prompt spectrum which was obtained by irradiating 12C beam on an Al foil withthe same set-up.
Figure 2 shows the level scheme of 218Ra. This level scheme is essentially the same as those(29, 30)

6267

17 -

434.3
( 27,28 )360.5( 26,27 )

460

5472
30 1.0( 24, 25)

193.7

23 -

258.0

21-

5171
4977

-isomer

4719

398.6
20 -

4321
556.9
/ 51. 4- +220.5+! 199.1

1~3 764 -isomer~ 3 713130.0- - 3583
290. 1 "-3492"-3293

613.3

13-

2 679
344.2
2 335
309.2
2 026
314.9
203.5
343.5

16+

3290.1

5833

1 711
1 508
1 164

2830. 4434.7
( 5)2394.8429.0(6)1 9648

14+

440.1
(2 9)
2530.7299 .7
(13)
12+

13-

2971.3311. 12660.2547.3 ( 7)281. 9(20)
10+2112.9
415.5

415.5

2034.2337.3
1 696.9

1 548.8425.2(19 )1 123 2381. 4( 69 )
741.8
389.6( 100 )
352.2
352.2
(99)
0

3 394.7
423. 1(16)2971.6
14

206.3
(50 )
6+

148.1
7-

219.3
(65)
83.2(2 ) 5-

4+

353.6
( 14 )
302.6 1 342.5( 5)
1 039.6

297.8
(2 1)

2+
2~~ Ra1 30

0+

Ea = 8.39Me V
T, jz= 14/1 s

475.9
688
688.2
0

0+

Fig. 2.

A level scheme of 218Ra. Transition-and level-energies are in keY unit. The numbers
in parentheses are relative transition intensities
after corrections of the internal conversion
Fig. 1.

A level scheme of 216Ra. Transition-and level-energies are in keY unit.

coefficients~)

The arrow starting at the groundstate indicates the ground state Q-decay~)

50

reported by other groups.5) Ratios of the reduced transition probability, B(E 1)/Il(E2), are of theorder of 10-6 fm- 2 for both transitions depopulating the ground state band and the negative parity
band. It seems to be not probable that the negative parity band in 2I8Ra would be an octupole
vibrational band as proposed by Fernandez-Niello et a1. 5) since the model coupling an octupole
vibration to a quadrupole core 7) prohibits the E 1 transitions from the ground state band to thenegative parity band.

Refereces
1)
2)

Y. Itoh, Y. Gono, M. Sasagase, T. Kubo, M. Sugawara, S. Hayashibe, K. Hiruta, andT. Nomura: RIKEN Acce1. Progr. Rep., 12, 64 (1981), and references therein.
A. Chevallier, J. Chevallier, B. Haas, S. Khazrouni, and N. Schultz: Z. Phys., A308, 277(1982).

3)
4)

Y. Itoh, Y. Gono, T. Kubo, M. Sugawara, and T. Nomura: to be published.
D. Horn, O. Hausser, B. Haas, T.K. Alexander, T. Faestermann, H.R. Andrews, and D. Ward:
Nucl. Phys., A3l7, 520 (1979).

5)

J. Fernandez-Niello, H. Puchta, F. Riess, and W. Trautmann: ibid., A391, 221 (1982);

6)

M. Gai, LF. Ennis, A.C. Hayes, r..1. Ruscev, E.C. Schloemer, S.M. Sterbenz, N. Tsoupas,
and D.A. Bromley: Proc. Int. Conf. on High Angular Momentum Properties of Nuclei at
Oak Ridge, USA, (ed. N.R. Johnson), p. 118 (1982).
C.M. Lederer and V.S. Shirley, ed.: "Table of Isotopes, 7th ed.", John Wiley & Sons, Inc.,

7)

New York (1978).
D.R. Zolnowski, T. Kishimoto, Y. Gono, and T.T. Sugihara: Phys. Lett., 55B, 453 (1975).

51

III-1-16.

In-BeamQ:'-

and r-Ray Study on

215Fr

and 21~C

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

NUCLEAR REACTION 209si( 12C, 4n), E = 80 MeV; 205-yI( 13C, 3n), E = 65 MeV; measured][

E'Y' I'Y' 'Y(O), 'Y'Y-coin , Ea , la' a-y-coin. 217Ac, 21SFr deduced levels, J, 1T, Tl/2' 'Y&.

The a-decays from the excited states in the N = 128 isotones were studied using in-beamspectroscopic techniques. The nuclei 215Fr and 217 Ac were produced by the 205Tl(13C,3n)215Fr(at E = 65 MeV) and 209Bict 2C, 4n)217Ac (at E = 80 MeV) reactions, respectively. The a-particle
spectra were taken by a 500 Mm Si detector using a catcher-foil of 30 Mm carbon so that theenergy resolution did not depend on the target thickness. The 'Y"rays were measured by standard
in-beam spectroscopic techniques as well as a- 'Y coincidences.
(1) 217 Ac
This nucleus was studied previously by the in-beam a- and 'Y-ray spectroscopy. 1) ,2) The
a-decays of 9.65, 10.54, and 11.13 MeV were identified as decays from the 217Ac nUcleus.1)
A level scheme of this nucleus was studied by Maier et al. 2) However, the excitation energy ofthe state which deexcites by the 10.54 MeV a-decay was quite ambiguous.
We have performed an a-')' coincidence as well as an extensive 'Y-,), coincidence measurementon 217Ac. Several new a-lines such as 9.74,10.86,11.03,11.28,11.40,11.54,12.15, and 12.33
MeV lines were observed. This resulted from the improvement of the energy resolution of thea-spectrum. Relatively strong peaks at 10.590 and 9.650 Me V were used as gates in the a-')'coincidence measurement. The 'Y-rays of 327.6, 351.5, and 381.8 keV were observed in the 'Y-ray
spectrum which was obtained by setting gate on the 10.590 MeV a-line. The level scheme
obtained is shown in Fig. 1. Qa-values of the other two a-decays of 11.28 and 12.33 MeV fit to
the energies of the deexcitations of the 1682 and 2762 keV states to the ground state in 213Fr,
respectively, within the experimental accuracy. The proposed spins and parities are deduced fromthe 'Y-ray angular distribution measurements.
(2) 215Fr
This nucleus has been identified through the ground state a-decay of 9.365 MeV (Ref.3).
Nothing has been known on the excited states in this nucleus. A delayed a-particle spectrum
was taken after the 205T 1(13C, 3n)215 Fr reaction. Two new a-lines were observed at 10.760 and
10.909 Me V which decay with a half-life of 9.8 ± 1.4 ns. The 'Y-ray spectrum was taken incoincidence with the 9.365 MeV a-decay of the ground state in 215 Fr. Strong 'Y-rays of 650,
450, 290, and 201 keV were assigned to the main cascade in this nucleus using the levelsystematics for the N = 128 isotones. Qa-values of the two new a-lines fi t to the decay energies
from the 1411 and 1613 ke V levels in 215Fr to the ground state in 211 At. A level scheme* Hitachi Computer Engineering.

52

3263
501.6
2762

n
/31/2'+)

371.7
2390

Q

Q
Q
1/

u

29/2

380.0

t U2 = 9.8 ± 1.4 ns

2010----- 1612.5
201.6
1410.9

327.6
1682
1529
1498

290.2
1120.7
450.5

1147
1019
957

670.2

670
660

670.2

660.3

120 ns0215
85 F r

0

21~
8 C

9/2

21~
87" r

Fig. 1.

211At
87

Level scheme of 217Ac.

Fig. 2.

Level scheme of 215Fr.

obtained is shown in Fig. 2.
We have so far studied a-decays from the excited states in the N = 128 isotones 215Fr, 217 Ac,
216Ra(Ref. 4) and 214Rn(Ref. 5). Systematics of these a-decays and the low-lying excited states isshown in Fig. 3 including nuclei 212Po(Ref. 6) and 213 At(Ref. 7) . The largest yield of the a-decay
from the excited states in each of 212po, 214Rn, 215Fr, and 216Ra is observed as deexcitation of
about 1.5 MeV level which corresponds to the excitation energies of the 8+ states in theeven-even nuclei in these isotones. About the same yield of the a-decay as those mentioned above
which is about 2.5 % of the intensity of the ground state a-decay was obtained as deexcitation of
the 957 keY state in 217Ac. This state is populated through the 17/2- state at 1147 keY promptly.
The 'Y-ray which deexcites this state was not observed.
On the otherhand the half-life of the a-decay from this state to the ground state in 213Fr
whose spin and parity are 9/2- is shorter than 4 ns. The reduced a-decay width, 'Y&, for thisa-decay is deduced to be less than 10 ke V. This indicates that the angular momentum difference
from 9 / 2 may not be larger than 4n. Hence the probable spin parity assignment to this states is
17/2-. The 'Y& value of 10 keY is about the same as those of ground state a-decays in the N = 128
isotones. However, the reduced a-decay width of 10 keY is very large for the excited state of
N = 128 isotone. It may be worthwhile to point out that the a-decay from the 957 keY state in
217 Ac does not follow the sys.tematic trend in N = 128 isotones.

53

(211

4719

810ns

------- --

3263

456

2762

13

2679

11-

2335

:31/2

2390

2026

29/2-

2010

,

1750

25/2-

__ J§!I~~ __

1682
1529

1474
14ns
1354 ( 19/2-)

1498
1164

1131

1147
1019
957

13/2-

688

670
660

o
213
85 At

217

89 Ac

Fig. 3.

Systematics of the low-lying excited states
and the a-decays from them in the N = 128 isotones.

References
1)

T. Nomura, K. Hiruta, T. Inamura, and M. Odera: Nuc!. Phys., A217, 253 (1973).

2)

K.H. Maier, D.J. Decman, H. Growe, and H. Kluge: Proc. 4th Int. Conf. on Nuclei Far from
Stability Line, Hersingor 1981, CERN 81-09, p. 183(1981).

3)

Table of Isotopes, 7th edition, (ed. C.M. Lderer and V.S. Shirley), John Wiley, New York(1978).

4)

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

5)

Y. Gono, K. Hiruta, T. Nomura, M. Ishihara, H. Utsunomiya, T. Sugitate, and K. Ieki:
1. Phys. Soc. Japan, 50, 377 (1981).
R.M. Lieder, J.P. Didelez, H. Beuscher, D.R. Haenni, M. Muller-Veggian, A Neskakis, and6)

C. Mayer-Boricke: Phys. Rev. Lett., 41,742 (1978); P. Lemmertz, L.1. Alquist, R. Fass,
H. Wolnik, D. Hirdes, H. Jungclas, R. Brandt, D. Schardt, and J. Zylicz: Z. Phys., A298,
311 (1980).

7)

T.P. Sjoreen, U. Garg, and D.B. Fossan: Phys. Rev. C, 21,1838 (1980).

54

III -1-17.

Numerical Analysis of 1280 MeV
on 94Zr,

110Pd,

208 Pb Reactions

148Sm, and

170Er

Based

on the Linear Response Theory

S. Yamaji, A. Iwamoto, * K. Harada, * and S. Yoshida(NUCLEAR REACTIONS Analysis for 208Pb-induced reactions on 94Zr, llOpd, 148sm ,]land 170Er, E = 1280 MeV, linear response theory, two-center shell model.

We have solved the equations of motion for 1280 MeY 208Pb + (94Zr, 1l0Pd, 148Sm , 170Er)
reactions 1) in the framework of the linear response theory, 2) taking the distance R between two
colliding nuclei and deformation 0 of each nucleus as collective variables. The method is almost
the same as in Ref. 3 except for the following four points taken into account.
(1)
The statistical fluctuations 2) are included.
(2) The time-dependent potential 4)
Y (~(t)) = yes) (1 -~(t)) + yeA) Ht)(1)

is used instead of the adiabatic potential yeA) in Ref. 3. The order parameter Ht) in thisexpression is assumed to beHt) = exp [ - {£~ dt'l(l + exp(R(t') - (R 1 + R 2 ))/a))} Iro J '(2)where RI and R2 are radii of two nuclei. The parameter a is taken to be 0.9 fm and the relaxation
time r 0 is taken to be 25 X 10-23 sec. The potential obtained by folding the Yukawa-plus,exponential interaction by the densityS) is used as the adiabatic potential yeA) and the proximity
potentia1 6) is used as the sudden potential yes). In Fig. I, these potential yeA) and yes) for the
spherical shape are shown as a function of the distance R by the dashed and solid lines,
respectively. The deformation effect is neglected in the calculation of yes).
(3)
For the friction tensors, the following expression is assumed,~(Ht)) = ~(S) (I - Ht)) + ~(A) Ht)

~

~

~

for (/l,lJ = R, 0).

(3)

A microscopic calculation of friction tensors ~(A)has been performed using the two-center shell
J.lV
model on the basis of the linear response theory.7) For ~(S),the following form is assumed,
JJ,V~~k = 0.0025 (ay(S)/aR)4, ~~1 = ~~s2 = 0.0.
(4)

The tangential and rolling frictional forces F t and Fr written in the forms of F t =
2

.'

.,

-

" .

-(R/( R I+ R 2)) ~RR (RI(e I - eo) + R 2(8 2 - 8 0)) and F r - -1.2(R/R I+ R2)~RR(e I - 8 2), respectIvely,

are included in the equations of motion, where 8 0 is the polar coordinate between the centers of two
nuclei and 8 I and 8 2 are the angles specifying the orientation of two nuclei. In the present
calculation with this strong rolling frictional force, it is verified that the sticking condition has
been achieved when the deforming motion starts. This satisfies the condition imposed on thepresent calculation that the system has to posses the symmetric axix throughout the collision.
* Japan Atomic Energy Research Institute.

55

500

500

Fig. 1.

The sudden potential yeS) andadiabatic potential yeA) for the spherical

450
450
400

~ 400
:>

shape with the neck parameter E of 0.8
defined in Ref. 3 versus the relative
distance R.
The difference between the solid

350 - -----_

-,

350

.....

""\
\
300

300

R (fm)and dashed lines in the asymptotic region
comes from the fact that the adiabatic
potential yeA) is calculated under theassumption of the uniform charge
distribution of the whole system.
Horizontal arrows show the center ofmass energies for four reactions.

The experimental resultsl) in Fig. 2 are compared with the calculated results in Fig. 3.
Concerning the angular distributions do/de, the relative peak positions for four reactions are well
reproduced by the calculation, although the yields in the forward angles cannot be reproduced.
The small pockets in the sudden potential for the reactions 208Pb+94 Zr and 208Pb+ ll Opd keep theorbits which reach within the nuclear surface staying for a long time in the interaction region.
These orbits contribute much to the cross sections near the peak position. For the reactions
208Pb+ 148Sm and 208Pb+ 17 0Er, there are no pockets in the sudden potentials, which explains thebroader peaks at backward angles.
Concerning the total kinetic energy loss spectra do/dE , the maximum at the energy loss of
120 MeY in the experiment for the reaction 208Pb+ 94 Zr is well reproduced by the calculation,
including a degree of freedom of deformation. In Fig. 4, the adiabatic potential yeA) for thereactions 208Pb+94Zr and 208Pb+ 17 0Er are shown as a function of the deformation for several
values of the distance R. The potentials for both cases have a minimum at 0 ,. . ., 0.4 in the surface
region. This minimum disappears outside the nuclear surface. For the case of the reaction
208Pb-t94Zr, it is found that the deformation increases rapidly and reaches 0.4 during the collision
for most partial waves contributing to the cross sections. In this case, the deforming motion isfaster than the radial motion due to the attractive pocket of the sudden potential and also dueto the gentle slope in the radial direction of the adiabatic potential. As the target nucleus becomes
heavier, the attractive pocket in the sudden potential becomes shallower or even disappears andalso the slope in the radial direction of the adiabatic potential becomes steeper, as can be seenin Fig. 1. Therefore, the maximum deformation obtained becomes smaller and the effect of
deformation degree of freedom on the cross section becomes weaker.
As the conclusion, it can be said that the analysis based on the linear response theory for
the Pb-induced reactions on 94Zr, llOpd, 148Sm, and 170Er can explain the systematic feature of theangular distribution and kinetic energy loss spectra.

56

(EXP)

- _ _ 2oSPb+ 170Er____ 20Spb+ 148Sm------208Pb+ " OPd--20SPb+ 94 Zr

ELob= 1280 MeV(EXP)

2osPb+ 94 Zr 2osPb+l10Pd 2osPb+14SSm 208 Pb+170E

~ 40

40

40

30

30

~

~ 30

Fig. 2.
Experimental results. The
upper figure shows angular distributions
for deep inelastic collision(DIC) eventswith energy losses exceeding 20 MeV.
The lower figure shows total kinetic
energy loss spectra. The arrows indicate
the position of the Coulomb barrier
calculated by assuming two spherical
nuclei.

Bem

(CAll

ELob = 1280 MeV

2osPb+ 94 Zr

208Pb+I10Pd

2osPb+ 14 SSm 208Pb+170Er

40

40

40

40

~ 30

30

30

30

~

E

Fig. 3.
Calculated results. The upper
figure shows angular distributions for
DIC events with energy losses exceeding

20 MeV. The lower figure shows total
kinetic energy loss spectra.

57

20S Pb+ 9 .1 Zr
R(f m)( 9.5 )

350

(11)

( 12. 5)
(14 )

>Q)

(15 5 )

L

300
208

Pb + 170 Er

R(fm )( 9.5 )

11

12.5
14

Fig. 4.
The adiabatic potentials yeA)for the reactions 208Pb + 94Zr and

500
-0.2

00

02
;;

04

0.6

208Pb + 17~r for several values of the
distance R versus the deformation 8.

References
1)

K. E. Rehm, H. Essel, P. Sperr, K. Hartel, P. Kienle, H.J. Korner, R.E. Segel, and W. Wagner:
Nucl. Phys., A366 , 477 (1981).

2)
3)

H. Hofmann and P. J. Siemens: ibid., A275 , 464 (1977).
K. Sato, S. Yamaji, K. Harada, and S. Yoshida: Z. Physik, A290, 149 (1979).

4)

W. Norenberg and C. Riedel: ibid. , p. 335.

5)
6)
7)

H. J. Krappe, J. R. Nix, and A. J. Sierk: Phys. Rev. C,20, 992 (1979).
J. Blocki, J. Randrup, W. J. Swiatecki, and C. F. Tsang: Ann. Phys. (N.Y.) , 105 , 427 (1977).
A. Iwamoto, K. Harada, S. Yamaji, and S. Yoshida: Z. Physik, A302 , 149 (1981).

58

III-1-18.

Effects of the Mass Fragmentation Potential on
the Mass Diffusion Phenomenas. Yamaji, A. Iwamoto,* K. Harada,* and S. Yoshida(NUCLEAR REACTIONS Analysis for 208Pb + 94 Zr reaction"

l~ = 1280 MeV, linear response theory, two-center shell mOde0
We report on the analysis of the relaxation phenomena in the mass exchange for the reaction
1280 MeV 208Pb + 94Zrl) based on the linear response theory.2) The relaxation phenomena in themass exchange have been shown to be well reproduced by the theoretical values of mass diffusion
coefficients DA for various reactions. 3),4) However, the value of DA obtained by the same analysis
as in Ref. 4 for the above mentioned reaction is 0.25 Tj10-23 sec and about ten times larger thanthat of Ref. 1, where T is the temperature of the intrinsic state in units of MeV.
We extend the study 4) by solving coupled equations of motion with statistical fluctuations inthe same way as in Ref. 5. The new point is that the projectile-like mass number Al is taken into
account as a collective variable in addition to the relative distance R and deformation 8.
The solid circles
Figure 1 shows the total kinetic energy loss (TKEL) versus varianceai.

corresponding to the experimental data are well reproduced both by the solid line obtained by thepresent calculation and the dashed line obtained by Rehm's analysis.
It is worth mentioning the reason why both calculations have succeeded to reproduce thedata in spite of using different values of DA. For that purpose, the kinetic energy loss E* andthe varianceas a function of collision time t are shown both for the present and Rehm's
analyses in Fig. 2. We define the collision time t during which the mass exchange occurs by thetime during which two colliding nuclei are staying within the distance CI + C2, where Ci(i = I or 2) is the half-density radius calculated by C.1 = a.1 - 1.0/a.1 using semi-major axis a.1 ofeach deformed nucleus. One can obtain the results of Fig. 1 from those of Fig. 2 by removing
the collision time. Rehm et al.l) obtained 0.03j10-23 sec , (0.15/l0- 23sec)2 and 76 X 10-23sec forai

the values of the mass diffusion coefficient DA' ensemble average of square of inertia mass
and relaxation time r by the least square fitting of the expression
transfer

A5

~

150

/~/.
z:: 100 ~. ,/.______---______ - ~ a2 v =00

>

Q)

..J

~

f-

-

aA2
I

.//

t-/

50.

o

1280 MeV 208 Pb+ 94 Zr

300* Japan Atomic Energy Research Institute, Tokai, Ibaragi, Japan.

Fig. 1.
TKEL versus a~ for thereaction 1280 MeV 208Pb + 94Zr.
The solid circles correspond to theexperimental data. The solid anddashed lines show the present andRehm's results, respectively. The
dot-dashed line is calculated by
setting a 2v(A)/ a = 0.0.

Ai

59

400

400
.4 = 302 sys tem

200( E= 0.8 )

150
350

R= 12. 5tm

100

"'''t

b

- - Prese nt---- Rehm' s

50

>Q)
L

300

350

300

300

<i

0

.,.. ..,

150:s;::0,-- ---

".,

".,

/

/

:;-

"

I

Q)

I

100

L

I

I

-.J

I

w

~

f-

1280 MeV 208 Pb+ 94 Zr

50o

250 ~~~~~~~~~~ 250

100

400
300
t (l0 - 23 sec )

160

500

ai

200

220

240

The adiabatic potential yeA)
Fig. 3.
for the system of the total mass numberof 302 versus the projectile-like mass
number Ai. The upper lines show the
adiabatic potentials for several values of
8, fixing R = 12.5 fm. The lower lines
show the adiabatic potentials for several
values of R, fixing 8 = 0.2. The neckparameter E defined by Ref. 4 is taken
to be 0.8.

Fig. 2.
and TKEL versus
the collision time for the reaction
1280 MeY 208Pb + 94Zr. The solidand dashed lines show the present
and Rehm's results, respectively.
The dot-dashed line shows
calculated by setting a 2y(A) / a

ai

180

Ai

= 0.0. The arrows indicate thecollision times obtained by thepresent calculation with given angularmomenta.e .

ai(t) = A~r2(1 - exp( - t/r))2 + 2DAt
(1)

- DA r(1 - exp( - t/r)) X (3 - exp( - t/r»)

to the experimental values. The small value of DA' that is , 0 .03/1 0 -23sec can be obtained fromthe slope of the dashed line ofexpressed by(t) ""
r + DA(2t - 3 r) for t ~ r . It canbe verified that the contribution from (Ao r)2 term to
at t = 500 X 10-23 sec is 120 and that

ai

ai,

A6

ai,

from DA(2t - 3 r) is 20. Therefore , since the contribution of (Ao r)2 is rather large even att ~ r , (t) cannot be equal to 2DAt corresponding to the usual expression without the effectaiof the potential.

60

On the other hand, in the present case, the linear response theory2) gives the following
expression to the variance ai (t):(2)

under the assumption of the over-damped motion of mass exchange and of the constant valuesof DA and C, where D A and C are expressed in terms of the friction 'Y AA corresponding to mass
exchange, adiabatic potential yeA) and nuclear temperature T in the forms of D A = T /'Y AA and
C = T I'Y AA . a 2y(A) 1 aAi. From the present numerical calculation, 'Y AA is found to be (4'""5)Me V·
10-23sec in the region of 0.0 ~ a ~ 0.4 and 12fm ~ R ~ 17fm, where mass exchange occurs. The
potential curves yeA) obtained by folding the YUkawa-plus-exponential interaction by the density 6)
which is also used in the coupled equations of motion are shown in Fig. 3. They can beapproximated very well by the parabolic curves. The value of a 2y(A)/a Ai is found to be(2'""-'3) X 10-2Me V. The centrifugal potential is found to increase the above value by at most 10
percents for P = l30h. The temperature T can be estimated by the relation T = 3.46 )E* 1A,
in terms of TKEL E~ T ranges from 1.5 MeV to 2.5 MeY in the present case. Then taking'Y AA '""4.5 MeY'10- 23 sec, a2y(A)/aAi '""-' 2.5XIO-2MeY and T""'2 MeY, we obtain D A""'0.5/l0- 23sec
and C""'O.O 1/1 0-23sec . This approximate estimation by substituting these values into Eqn. (2)roughly reproduces solid line for ai which is obtained by solving three dimensional coupledequations of motion. If the effect of the fragmentation potential is neglected, that is, C = 0.0
MeY, the dot-dashed line for a;' is roughly reproduced.

In conclusion, the reason why Rehm et al. got the small value of DAis that the large
contribution of (Ao r)2 to ai reduces DA even at t ~ r. The large value of DA obtained by the
relation DA = T I'Y AA in the present calculation can also reproduce the experimental a;' for thereaction 1280 Me Y 208Pb + 94Zr as well as for other various reactions,4) if the effect of thefragmentation potential is included.

References
1)

K. E. Rehm, H. Essel, P. Sperr, K. Hartel, P. Kienle, H. 1. Korner, R. E. Segel, andW. Wagner: Nucl. Phys., A366, 477 (1981).

2)

H. Hofmann and P. J. Siemens: ibid., A275, 464 (1977).

3)

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

4)

S. Yamaji, A. Iwamoto, K. Harada, and S. Yoshida: Phys. Lett., 106B, 433 (1981).

5)

S. Yamaji, A. Iwamoto, K. Harada, and S. Yoshida: p. 54 in this report.

6)

H. 1. Krappe, J. R. Nix, and A. 1. Sierk: Phys. Rev.C, 20,992 (1979).

61

III-1- 19.

Exact Finite-range Coupled-channel Born Approximation
Calculations with Spin-orbit Interactions

T. Takemasa

NUCLEAR REACTION Exact finite-range, zero-range, spin-orbit, CCBA,[ ll&Sn(p, t)

116

J

Sn reaction, 0+ ground state, 2+ excited state, Ep = 52 MeV.

The experimental data on (p, t) reactions are now accumUlating. 1) Since there .is evidence
that multistep processes play an important role on (p, t) reactions,1) and the assumption of azero-range (ZR) interaction responsible for the (p, t) transfer process has not received any physicaljustification, it is important to carry out exact finite-range (EFR) coupled-channel Born
approximation (CCBA) calculations with spin-orbit coupling.
We have developed the EFR spin-orbit CCBA code SOCCBA by modifying the CCBA
program without spin-orbit coupling which was used in Ref. 2. This code performs EFR-CCBA
calculations with spin-orbit coupling very efficiently and quickly, because we have used aninterpolation technique 3) to construct finite-range form factors. SOCCBA can couple up to fivestates in both the entrance and the exit channel with a maximum of 200 partial waves. Twenty
simultaneous transfer can be handled. Preliminary calculations are carried out for the 118Sn(p, t)116 Sn reaction at Ep = 52 MeV leading to the 0+ ground state (g.s.) and the 2~ excited state,
and are compared with the ZR-CCBA calculations, which are calculated by the computer program
MARS.4)
The results for the differential cross sections and for the analyzing powers are shown inlI S Sn(p, t)1 16 Sn

E p = 52MeV

10°-

EFR - CCBA---- ZR - CCBA
~
C

:::J

-2cu
~
I::l

""(j
-----

10- 1

10- 2

o

90
()c. rn.

( deg.)

Fig. 1.
Comparison of angular
distributions calculated by ZR-CCBA(dashed-curve) and EFR-CCBA (fullcurve). The ZR-CCBA curves arenormalized to the EFR -CCBA
curves.

62

lI B

Sn( p, t) 116 Sn

E p = 52MeV- E F R- CCBA---- ZR - CCBA

Og_S

1.0

q;
~ -0.5-<r:-1.0- O.5 ~---'------'-------;:;~-L-----L..----::l::---L------L------,J

o

30

60

Bc.m.

(deg . )90

Fig. 2.
Comparison of analyzing
powers calculated by ZR-CCBA(dashed-curve) and EFR-CCBA(full curve).

Figs. 1 and 2, respectively. The nuclear model and parameters used are the same as those ofRef. 2. The ZR-CCBA calculations are carried out by using the same parameters used in the
EFR-CCBA calculations. As is seen in the figures, there are rather large differences between the
EFR and ZR calculations in both the angular distributions and the analyzing powers. It should be
noted that the calculations are very sensitive to the radius parameter of the bound states and the
choice of the optical parameters. This calculation, therefore, was only included to show the finite
range effects. A comprehensive analysis of this reaction is currently underway.

References
1)
2)
3)
4)

G. G. Ohlsen , R. E. Brown, N. Jarmie, W. W. McNaughton, and G. M. Hale: Polarization
Phenomena in Nuclear Physics - 1980 AlP Conf. Proc. No. 69, AlP, New York (1981).
T. Takemasa, T. Tamura, and T. Udagawa: Phys. Lett., 87B, 25 (1979).
T. Tamura: Phys. Rep., 14,59 (1974).
T. Tamura and T. Udagawa: University of Texas, Center for Nuclear Studies Technical Report
No.3 (1972) , unpublished.

63

III-l - 20.

Effects of Two Particle-Two H ole Excitations
on the Mass Distributions in lon-Ion Collisions

M. Tohyama and S. Yamaji

NUCLEAR REACTION DIC one-dimensional calculation of mass
[ distributions, time-dependent coupled-cluster approximation.

J

The time-dependent Hartree-Fock (TDHF) theory has been extensively used to describe the deep inelastic
heavy- ion collisions. Although the TDHF calculation gives mean values of the mass distributions and total
kinetic energy loss etc, it can not reproduce the widths of these observables. I ) Here our concern is related to thewidths of the mass distributions. In a microscopic theory, the number operator which counts probability in theright half plane is(1)
where < Q I {3 >R is the right-hand overlap integral of the single-particle wave functions. The mean number NRof particles and the standard deviation oR of the mass distribution in the right fragment are expressed as
(2)
and
02 =

R

where << NR2> _ ( < NR
»2'

(3)

NR > and < N~ > denote the expectation values of NR and N~, respectively:
and

(4)

If I 'l' > is a single Slater determinant, the standard deviation becomesA

O~ TDHF = L

v=IA<vlv>R -L <v Iv'> R <v'lv>R

(5)

v,v'

The widths of the mass distributions calculated with this formula are always an order of magnitude smaller thanobserved values. 1) This comes from the fact that the TDHF theory does not give mean values of two-bodyoperators correctly. To treat the widths of the mass distributions, we have to take into account higher
configurations. It is an interesting problem to study how much the widths of the mass distributions are increased
by improving the wave function.
We study the effect of two particle-two hole excitations on the widths of the mass distributions. We use
the time-dependent coupled-cluster approximation (TDCCA). In this theory the wave function is written in theexp(S) form: 2)

(6)
where

64

""

(7)

S

and Sn is represented by n particle-n hole operator referring to a Slater determinat I <I> > ,(8)

The indices v.(p..) and p.(a.) denote normally occupied states and normally unoccupied states, respectively. The
J J
J J
suffix A means antisymmetrization of the labels v 1 •.• vn. A set of coupled nonlinear equations for the amplitude< Pl··· Pn \ Sn \ v 1 ···vn > is obtained by projecting the Schrodinger equation as follows:++""a",'"S< <I> \ a vI... a a ···· a e- S (i vn pnpI
at - H) e \ <I> > = 0 .

(9)

We take units such that n = 1. Hoodbhoy and Negele 3) have derived a couple of equations by truncating Eqn.
(9) at the n = 2 level. The first equation determines the time evolution of the single-particle basis, which
involves the effects of two-body collisions on the single-particle potential via < PI P2 \ S2 I v IV 2 >. The second
equation specifies the time evolution of < PI P2 i S2 I VI V 2 >. It is a very hard numerical task to solve
self-consistently these time-dependent coupled equations. We assume as a first step that the amplitude< PIP 2 I S2 I V I V 2 > is small and take the lowest-order terms in the coupled equations. As discussed later, thisassumption is justified if incident energies are small. The equation for the single-particle basis then becomes the
TDHF equationi -a
at lP v (t) = h(t)lPv (t) ,(10)where h(t) is the Hartree-Fock (HF) Hamiltonian. The equation for < P 1 P2 \ S2 1 v 1 v2 > becomes(11)

where V is the two-body residual interaction. This equation can easily be integrated. The two-body density
matrix is related to < PI P2 \ S2 \ VI V 2 >.4) Using the two-body density matrix, we obtain the expression for the
standard deviation a R of the mass distribution in the right-hand fragment.
We have performed calculations for one-dimensional collisions of two fragments Al = 4 and A2 = 8. In
Fig. 1(a) we show the results of a R for various bombarding energies. The results of the TDHF calculation are
also shown. The standard deviation a R are enhanced about three times as compared to the TDHF results. In
Fig. 1(b) the mean numbers of particles on the right-hand side are compared with the TDHF results. As for themean number of particles, the TDCCA calculation gives almost the same results as the TDHF calculation. We
remark that two particle-two hole excitations affects much the observables related to the two-body operators.
The decrease in a R at 2 Me V / A is due to a little change in the reaction mechanism. As seen from Fig. I (b), atlower energies the light fragment gains mass. The situation is inverse at higher energies.
In Fig. 2 we show the density distributions in the initial and final states. The effect of two-body collisions
is remarkable in the final stage of the collision as seen in one-dimensional calculations with a phenomenologicalcollision term by Grange et al. 5) However, at these bombarding energies the difference between the TDCCA
density and the TDHF one is rather small. We consider therefore that the assumption that the TDHF equation
describes the time evolution of the single-particle states is valid.
In summary we have found that two-body collisions have a large effect on the widths of the mass
distributions. It is an interesting problem to extend the present calculation to realistic three-dimensional collisions.

65

OR

-

NR

(a )

TOCCA

~

1.0

(b )

10
8

0.5

o

5

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

_.e

TOHF

2

4

MeV/A

3

TOCCA

• TOHF
2

CENTER OF MASS ENERGY

3

4

MeVlA

CENTER OF MASS ENERGY

Fig. 1.
Standard aeviations oR (a) of the mass distributions and the mean numbers NR (b) ofparticles in the right fragment for Al = 4 and A2 = 8 collisions. The solid line connects the TDCCA
results (open circle) and the dotted line, the TDHF results (closed circle).

- - TDCCA

t=O...... TDHF

] 2.

,...

"-

>-

t:

(j)

~
1.0
o

10

20

- - TDCCA...... TDHF

30

t = 9.0 X10

40 (1m)
-22

sec

>-

t:

(j)

z

~

Fig. 2.

1.0

10

20

30

DISTANCE (fm)40

The density distributions in theinitial and final states for Al = 4 and A2 = 8
collisions. The solid line denotes the TDCCA
calculation and the dotted line, the TDHF
calculation. The center-of-mass energy is
2 MeV/A.

References
1)
2)

K.T.R. Davies and S.E. Koonin: Phys. Rev. C, 23, 2042 (1981).
H. KLimmel, K.H. Liihrmann, and J.G. Zabolitzky: Phys. Rep., 36C, 1 (1978).

3)

P. Hoodbhoy and l.W. Negele: Phys. Rev. C, 19, 1971 (1979).

4)
5)

K. Emrich, J.G. Zabolitzky, and K.H. Liihrmann: ibid., lQ, 1650 (1977).
J. Richert, D.M. Brink, and H.A. Weidenmiiller: Phys. Lett., 87B, 6 (1979); P. Grange, 1. Richert,
G. Wolschin, and H.A. Weidenmiiller: Nucl. Phys., A356, 260 (1981).

66

111-2.

Atomic and Solid-State Physics

1.

Target Gas Pressure Dependence of REC X-Raysfrom Ne-Ion Bombardment

T. Kambara, Y. Awaya, A. Hitachi*, M. Kase,
I. Kohno, and T. Tonuma

We have measured energy spectra of X-rays from radiative electron capture (REC) process
by 5.5 MeV /amu Ne-ion bombardment on gaseous targets. In the process, an electron in a target
atom is captured into a K-shell vacancy of an incident Ne-ion with emission of a photon. 1),2)
We reported on the analysis of the shape of the REC X-ray spectra as a function of the target
atomic number. 2)
In the present work, the REC X-ray spectra for H2 gas target are analysed as a function of
the target gas pressure which is proportional to the target thickness. The measurement systemwith a Si(Li) detector was described in the previous report. 2) The pressure of the H2 gas target
contained in a gas cell was between 9 and 120 Torr and the distance between the entrance
window (7 ,urn thick Al foil) of the gas cell and the area viewed by the detector was about 70 mm.
The peak energy of the REC X-ray is shown in Fig. I (a) and the REC X-ray yield divided by
the gas pressure, referred to as relative yield hereafter, is shown in Fig. 1(b) as a function of thegas pressure. The REC peak shifts to higher energy and the X-ray relative yield increase when
the gas pressure increases.
These effects are explained by the fact that the charge state distribution of the projectile

(a )

4.02

+

;: 4.01

1.2

<lJ

...x:
1:)

a:;

: 4.00;;: 1.1

01
I-

(!;

<lJ

tiJ 3.99>-£ 1.0...x:a~ 3.98

0:::

o

50

100

Gas Pressure ( Torr)

Fig. 1.

o

50

100

Gas Pressure (Torr)

Dependence of REC peak energy (a) and REC relative yield (b) on thegas pressure for H2 gas target. The full curves show the calculation results basedon the charge equilibration process of the ions in the gas. The calculated resultof REC peak energy is lowered by 250 eV to fit the experimental data.
* Radiation Laboratory, University of Notre Dame.

67

Ne-ions depends on the gas target thickness. The REC process to the K-shell of the incident ion
in gas is possible for Ne 9+- and Ne lO +-ions, which have one and two K-shell vacancies respectively.
The capture cross section and the emitted X-ray energy for the capture by a Ne 9+-ion arelower than those by a Ne 10 +-ion, because a Ne 9+-ion has one electron in the K-shell. Therefore
the X-ray energy and the relative yield increase when the fraction of the Ne lO +-ion increases.
The dependence of the charge state distribution on the target thickness is due to electrontransfer processes between the ions and the gas atoms, which is described by rate equations. 3)
In the present experimental condition, most of the ions are at the charge states higher than 7+
after the ions pass through the entrance Al window. Then the charge state distribution of theions at gas target thickness x (atoms/cm 2) is as follows:
f8 = ~ exp ( -aJ! x)

f9 = ~ exp ( -

at x)

+ ~

8
0

8 L

9

0L -

0L

{exp ( -at x) - exp ( - O~ x)}

flO = 1 - f9 - f8'
where fq is the fraction of ion with charge q, f~ is that after the passage of the entrance windowof the gas cell and of is the electron loss cross section of ion with charge q. The electron capture
cross section is much smaller than o( according to calculations based on OBK model 4 ) and isotneglected in these formula. The values ofis taken from the calculation based on BEA model
20
which gives about 2.6 X 10- ~m2 for the cross section of the process Ne 9 + + H -+ Ne lO + + H + e. 5)
The cross section a~ is estimated by the same formula for the process F 8+ + H -+ F 9 + + H + e andthe result is multiplied by two, the number of electrons in the incident ion.
The values of ~ are taken from experimental data of charge state distribution of heavy ionsin Al presented by Northcliffe,6) which gives 62 % forfio and 35 % for ~.

The charge state fractions (fq) at the area viewed by the detector, at 70 mm of flight pathfrom the entrance window, are calculated for various gas pressures up to 120 Torr, whichcorresponds to 5.6 X 10 19 atoms/cm 2. The calculation predicts that the fraction of Ne 10 + ionsincreases from 62 % to 91 % when the ion beam passes through the gas at 120 Torr from theentrance window to the area viewed by the detector.
The X-ray peak energy is calculated by assuming that the REC spectrum consists of two
Gaussian peaks separated by 170 eV corresponding to transitions to Ne 9 + and Ne lO + respectively.
The REC relative yield is assumed to be proportional to 2f10 + o:f9 where 0: is the ratio of the
REC cross section for a Ne 9 + to that for a NelO+. It is estimated as the ratio of free electron
capture cross section by a point charge with Z = 9 to that with Z = 10, resulting in 0: = 0.7.
The results are shown in Figs. 1(a) and 1(b) by full curves. The calculated peak energy in
Fig. 1(a) must be lowered by about 250 eV to fit the experimental data. The agreement between
the calculated results and the experimental data is good for the X-ray relative yield. The shift ofthe peak energy in its relative value is also well reproduced by the calculation .
A more detailed report will be given elsewhere. 7)

68References
1)

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

2)
3)

Rep., 11, 86 (1978).
T. Kambara, Y. Awaya, A. Hitachi, M. Kase, I. Kohno, and T. Tonuma: ibid., 14, 88 (1980).
H. D. Betz: "Method of Experimental Physics: Atomic Physics, Accelerators" , (ed.
P. Richard), Academic Press, New York, 17, 73 (1980).

4)5)J. Eichler and F. T. Chan: Phys. Rev. A, 20, 104 (1979).
T. Shirai, K. Iguchi, and T. Watanabe: J. Phys. Soc. Japan, 42, 238 (1977).

6)

L. C. Northcliffe: Ann. Rev. Nucl. Sci., U, 67 (1963).

7)

T. Kambara, Y. Awaya, A. Hitachi, M. Kase, I. Kohno, and T. Tonuma: J. Phys. B: At. Mol.
Phys. , 12, 3759 (1982) .

69

III -2-2.

Target Gas Pressure Dependence of K-X Rays
from

11 0

MeV Ne Ions

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

The K-X rays from 110 MeV Ne 9+ ions (hydrogen-like) in gaseous targets with atomic number Zt ~ 10have been studied at various gas pressures up to 300 Torr. Last year we reported on measurements using a Si(U)detector with a resolution of 250 eV(FWHM).l) In the measurements, two peaks appeared in the energy spectrumof K-X rays: One from the transitions np - Is with n > 2 (1.21 - 1.36 keY) which were not resolved and theother due to the 2p -- 1s transition (1.0 ke V).
For the targets with Zt > 2, the former peak was found to shift to lower energy when the gas pressure
increased. In order to find out the reason for the energy shift, we made measurements of the energy spectrumof the former peak to resolve it into peaks arising from np - Is transitions of various values of n. The targets
were N2 and Ne gases, each of which was contained in a gas cell with pressure between 20 and 300 Torr. We
used a broad range crystal spectrometer with a plane crystal and a position sensitive proportional counter. The
details of the spectrometer were reported elsewhere. 2) We used an RAP crystal (2d = 26.12 A) for the analyser
and a 4 11m thick Mylar foil for the window of the position sensitive proportional counter. The foil was
supported by an 80 11m thick stainless steel mesh from the outside to hold the gas in the counter whose pressure
was about 3.2 atm. The electronic circuit system to analyze the signals from the counter was modified a little
to distinguish the low level signals due to K-X rays from backlash pulses of higher level noise signals. The
range of the energy of X-rays observed by the spectrometer was between 1.1 and 1.44 keY where the np - Istransitions with n greater than 2 could be observed. The resolution was about 10 eV (FWHM).
Examples of the observed spectra are shown in Fig. 1: Figure l(a) is for N2 gas target at 300 Torr andFig. l(b) at 21 Torr. Peaks from the transitions np - Is (n = 3,4, and 5) are well resolved. As seen in the
3p-1s (1209 keV)(a)4p-1s (1 .275 keV)

Fig. 1.

X-ray energy spectra of K-X rays
9

from Ne + ions in N2 gas at (a) 300 Torr and(b) 21 Torr.

70

spectra, the relative intensity between the transitions depends on the gas pressure. For example, the intensityof the 4p - Is transition is about 0.5 times as large as that of 3p - Is at 21 Torr and the ratio decreases to 0.3
at 300 Torr. In Fig. 2, the intensities of the 4p - 1sand 5p - 1s transitions relative to the 3p - 1s transition
are plotted against the gas pressure, where the dependence of the absorption of the X-ray photons on thetarget gas pressure is corrected. The result shows that the occurrence of the radiative transition from a higher
level decreases faster than that from a lower level when the gas pressure increases. It is the reason for the shiftof the peak energy observed in the low resolution measurements.
This effect is explained as a result of collisional quenching in which a Ne9+ ion in an excited state transfers
to another state by a collision with a target atom before it decays with a radiative emission .3) The probability of
the collisional quenching depends on the lifetime of the excited state r , the velocity of the ion v, the density ofthe target atoms N and the cross section of the quenching o. According to Matthews,4) the intensity of theradiation from the decay of the excited state is proportional to Nv/(1 + Nvro). Thus the relative intensity of theradiation from decay of a state i to that of a state j is proportional to (1 + Nvrjoj)/(1 + Nvrpi) which causes thetarget gas pressure dependence of the relative intensities.
The experimental data are fitted by the least square calculation using the expression described above. For
each value of the quenching cross section of the 3p state 03P' the most probable values of the cross sections of
the 4p and 5p states, o4p and 0sp, are derived. The values of the lifetime for the states are obtained by multiplying
the lifetime of the corresponding states of a hydrogen atom by 10- 4. The values of 04p and Sp are plotted°against the values of 03p in Fig. 3. The result is that the values of the quenching cross section for the 4p ana 5p
states are almost the same and larger than 1 X 10-l7cm2. This is consistent with that obtained by Matthews forthe quenching cross section of 23Pl metastable state of 30 MeV F 7+ ions. 4)

0.5

0

+

(a)

+

• •

0.4

CO

0:

-c

•

Q)

>= 0.2 -

~
~

co

<P

Q>

0:

X

• Y4 /Y 3

~

>I

•

0.3

<D

0 .1

<D

200 (Torr)

100

50

20

YS /Y3

Target Gas Pressure

0.5

+

0

0.4

(b )

+

+ +

co

0:

:2
Q)

~

>= 0.2

<I>

co
a:
X

+ Y4 /Y3

<j>

>I

+

0.3

4l
<I>

0.1
I

20

50

I

I

I

I

I

100

4>

Y S /Y 3

I

200 (Torr)

Target Gas Pressure
Fig. 2.
Target gas pressure dependence of the ratio of intensities of Sp - 1s transition (Y s) and4p - Is transition (Y4) to that of 3p - Is transition (Y 3) for (a) N2 target and (b) Ne target.

71

\a I

N2 -G as target

1.0

1.0

'"

(b )

N

a uE

'+-

c ~

c ~

0

Ne - Gas t arge t

o

0

1

E

u
1

:..::;0:"::;0OJ~

U .---<
OJ ~

(f)

(f)

u'---<

(f)
(f)

(f)
OJ
(f)-+-'

0.5

02

t; r.;>

tl.()Q

I'

= LD

I'
"/

-0

u c
~ C\l
:::J

(f)

I'
I'

tl.()QOJ-+-'

22 0.5
u

?

c LD
=

(f)
(f)

?

J::-o

"/

V

Q

O.q-

u

~

c

C\l

:::J

Q

O.q-

0

0. 5

Quenchin g cross sect ion of 3p- st at e (10-Fig. 3.

0

1. 0
16

cm

2 )

0.5

Quenchin g cross sect ion of 3p- st ate ( 10-1.0
16cm 2 )

Relation between values of quenching cross section for excited states 3p, 4p, and5p (a 3P ' a4p ' and asp) for (a) N2 target and (b) Ne target.

References
1)

T. Kambara, Y. Awaya, A. Hitachi, M. Kase, I. Kohno, H. Kumagai, and T. Tonuma: RIKEN Accel. Progr.

2)
3)

Rep. , 15 , 71 (1981).
A. Hitachi, H. Kumagai, and Y. Awaya: Nucl. Instr. and Meth., 195,631 (1982).
F. Hopkins: "Method of Experimental Physics, Vol. 17: Atomic Physics, Accelerators", (ed . by P.

4)

Richard) , Academic Press , New York, p. 355 (1980).
D. L. Matthews, R. J. Fortner, and G. Bissinger : Phys. Rev. Lett. , 36 , 664 (1976).

72

III -2-3.

High Resolution Measurements of K X-Raysfrom Argon Ions Impinging on Foils

Y. Awaya, T. Kambara, M. Kase, H. Kumagai,
J. Takahashi, J. Urakawa, T. Matsuo, and M. Namiki

The K X-ray spectra have been studied for Ar ions passing through various target foils inorder to investigate the dependence of multiple inner-shell ionization of projectiles on the atomic
number of target atom.
The Ar4+ ions were accelerated by the linear accelerator and momentum analysed by amagnet. The incident energy of Ar ions was 33.6 MeV and target elements were C, Mg,
AI, Ca, Ti, V, Cr, Fe, Co, Ni, Zn, Y, Mo, Sn, Ta, and Au. Targets were self-supporting foils but
for Ca which was evaporated onto a 10 Jlg/ cm 2 carbon foil. The thickness of the target was in
the range of 0.5 mg/cm 2 to 1 mg/cm 2 except for C, V, Zn, Ta, and Au. The thickness of C foil
was 80 Jlg/cm 2 and those of V, Zn, Ta, and Au foils were between 2 mg/cm 2 and 2.6 mg/cm 2 .
The angle between direction of the beam and the target was 60°. The Ar K X-rays emitted fromthe beam-incident side of the target foil at right angle to the beam direction were measured by abroad range X-ray crystal spectrometerl) with a position sensitive proportional counter(PSPC) anda crystal of Ge(111).
Examples of K X-ray spectra from Ar ions are shown in Fig. 1. The target elements are AI,
Ti, Fe, and Ta. KLn(n = 0,1 ... ) denotes single K-shell and n L-shell vacancy configuration in theinitial state. Relative intensities of KL n lines vary according to the atomic number of target
element, Z2' The group of peaks at higher energies are Ka hypersatellites and KI3 satellites. These
assignments are made by referring to the previous work on Ar K X-rays excited by N ions doneby Tonuma et al. 2) and by comparing the spectra obtained with and without a Rh-absorber,
whose Lm-absorption edge is 3.004 ke V, in front of the PSPC in the present work.
Assuming that the cross section of simultaneous single K-shell and n L-shell ionization,
uK,nL' is expressed by a binomial distribution 3) as
0K,nL~ (~) PL no - p L)8 - n OK'(1)

we obtained the value of PL for each target element. Here, PL is the ionization probability of an
L-shell electron at the impact parameter of zero and a K is the K-shell ionization cross section.
In the analysis, the intensity of each KL n line is obtained by the least square fitting of multiple
Gaussian curves, and a constant value of the fluorescence yield is assumed for KL n lines. The
obtained P L values are shown as a function of Z2 in Fig. 2.
When we discuss the P L values, some considerations are required on the thickness of thetarget. It affects the charge state of the projectile , the energy loss of the projectile whichcauses the change of aK,nL' the absorption of projectile X-rays in the target foil and the situation
wheather the projectile emits the X-rays in the foil or in vacuum and so forth.
According to the work by Baron,4) the 33.6 MeV Ar ion is considered to be in equilibrium
charge state in C-foil after it passes the thickness of 5 Jlg/ cm 2 and its value is about 11.5) Mostof Ar K-holes produced near the surface of the target foils will, therefore, be filled in the foils

73

E (keV )

:':J

~

0.90
077

3.2

3.0

X 10 3

AI

0.64
0. 51

~~
i

(f)

o(j2

(f)=

22
<U

.-

=(f)

QJ

I

I~

0.38

' ::,c

\

0.2 6

I~

~~

-+-'

0.5 -

Ol.

~::,c

QJ

rr
>-.
..c:

y\ i· ·"~""I

OA f(i)c~ 1.02x..c:~ 05 1

x

2'
c

:::J
0

u

0.3 r-

1. 92
Fe

1.28

o

I

I

I

I

I

I

I

I

10

20

30

40

50

60

70

80

90

Z2

0.64

013

~~
00~L-~3~28~~-4~5~6~L-~5~
84~~~7~12
Channel number

Fig. 1.

The K X-rays from 33.6 MeV
Ar ions impinging on AI, Ti, Fe, and Ta

target foils.

Fig. 2.
PL values for simultaneous
single K-shell and multiple L-shellionization of Ar ions vs. the atomic
number of target elements.
P L for 33.6 MeV Ar ions and 0 for
thinner foils;
x : P for 21.1 MeV Ar ions.
L
Curves are only to guide the eye.
_,0:for the target thicknesses used and the velocity of the projectile, except in the case of the C
target. The thickness of foil, which attenuates Ar K X-rays to a half of its initial intensity, isabout 2 mg/cm 2 for Ti and 0.3 mg/cm 2 for Ta.
The effect of target thickness on PL was examined for C, AI, and Ni targets by using two foilsof different thicknesses: 20 and 80 Jlg/cm 2 for C, 0.20 and 1 mg/cm 2 for AI, and 0.45 and 0.89
mg/ cm 2 for Ni. The open circles in Fig. 2 show the P L values for thinner foils. It is found when
the thickness of the target increases, the PL value decreases. Change of PL with the incident energy
was also studied for 80 Jlg/cm 2 C, 0.2 mg/cm 2 Al and 0.9 mg/cm 2 Ti targets. The P L values for
E = 21.1 MeV are shown by crosses in Fig. 2.
By taking into consideration these facts and also the decrease of Ar K-shell ionization crosssection owing to the energy loss of Ar ions in the target , most of Ar K X-rays detected can be
regarded to be emitted within first 1 mg/cm 2 of the target and that the behaviour of P L values
vs. Z2 shown in Fig. 2 reflects the atomic structure of the target element in collision system.
As is seen in Fig. 2, the P L value displays oscillatory behaviour against Z2' It reaches thefirst minimum at around Z2 = 22 and probably the second one at around Z2 = 45, where theL-shell binding energy of highly ionized Ar ions matches the L-shell and M-shell binding energyof the target atoms, respectively. This may suggest that the electron capture cross section to the74

L-shell of the Ar ions from the target atoms varies according to Z2 and becomes large when thelevel matching occurs, even though the velocity of Ar ions is comparable to or a little higher thanthe velocity of bound electron concerned.
Further analysis is in progress.

References
1)

2)
3)
4)
5)

A. Hitachi, H. Kumagai, and Y. Awaya: Nucl. Instr. Meth., 195,631 (1982).
T. Tonuma, Y. Awaya, T. Kambara, H. Kumagai, I. Kohno, and S. Ozkok: Phys. Rev. A, 20,
989 (1979).
1. M. Hansteen and O. P. Mosebekk: Phys. Rev. Lett., 29, 1361 (1972); 1. H. McGuire andP. Richard: Phys. Rev. A, ~, 1374 (1973).
E. Baron: IEEE Trans. Nucl. Sci., NS-19, 256 (1972).
Y. Baudinet-Robinet: Phys. Rev. A, 26, 62 (1982).

75

III-2-4.

Argon l-MM Auger Spectra in Arn+ + Ar Collisions (I)

Identification of Auger Lines
A. Yagishita, T. Kambara, M. Kase, T. Tonuma,
T. Matsuo, J. Urakawa, J. Takahashi,
H. Kumagai, and Y. Awaya

Auger electrons are ejected from atoms or molecules when fast charged particles are incident
on them. Much information on both atomic structures and excitation mechanisms can be obtained
from the electron energy distributions. Consequently, a number of works concerning the ejected
electrons in ion-atom collisions has been reported so far.!) But, measurements of the electrons
originating from heavy-ion atom collisions are scarce in the energy range higher than a few MeV.
In order to investigate heavy-ion atom collisions in this energy region, we have constructed ahigh-resolution electron spectrometer. Some measurements have been made for the Auger
electrons produced in Arn+ + Ar collisions, using the beams from the heavy-ion linear accelerator.
The electron spectrometer consists of electron optical lenses and a hemispherical electrostatic
energy filter of mean radius of 50 mm. An electron gun is prepared for the alignment andcalibration of the spectrometer. The energy resolution 6E/E is about 10-4 at the best condition.
The target Ar gas is effused from a multi-channel capillary positioned a few milli-meters below
the collision region. The detail of the apparatus has been described in the previous report. 2)
The result of the measurement is shown in Fig. 1. It was obtained with incident energy of
4.3 MeV and at emission angle of 132 0 with respect to the direction of the ion beam. The rangeof measured electron energy is from 80 to 330 eV, scanning with 0.52 eV step interval. The
L-MM Auger peaks from the projectile Ar ions shift to the energy region below 80 eV in thiscondition according to the Doppler shift, so that the peaks which appeared are attributed to the

4.0

Ar3++ Ar ( 4.3 MeV )5 4 3 2 1 0
L 23 - MJ Ml

I I I I I I
5 4 3 2 1 0

3.0

I

0

I I I I I
4

x

I

~

L 23 - MI M23

3

2

L 23 - M23 M23
0

I

I

I

~ 2.0

u

An electron spectrum obtained
Fig. 1.
for (4.3 MeV - Ar 3+ + Ar) systemcompared with that for (I keV - e + Ar)
system, measured at 132 with respect
0

1.0

0

e+ Ar

200

100
El ectron energy (e Vlto the direction of the incident beam.
The lines above spectrum indicate thecalculated energies for the correspondingtransitions denoted at the right of them.
The number on each line shows thenumber of the 3p-hole in the initial state.

76

electrons from the targets. The energy of the electrons was calibrated by the measurement of
Ar L-MM Auger spectrum induced by 1.0 keY electron impact using the electron gun. Theenergy values of L-MM peaks were referred to the results by Werme et a1. 3) The present energy
resolution is 0.7 eV FWHM . The uncertainty of the energy determined is estimated to be lessthan ± 0.2 eV.
The spectrum is characterized by two sharp peaks located at 101 and 112 eV, and by a broad
peak extending through 120 to 200 eV. This structure is quite different from that obtained byelectron impact. For the identification of the Auger peaks, we compared the spectrum with thetheoretical calculation by Larkins, who have shown that the Auger lines shift to the lower energy
as the degree of outer-shell ionization increases. 4 ) The lines above spectrum in Fig. 1 indicate theenergies calculated with the adiabatic model by Larkins. Two isolated peaks, at 101 and 112 eV,
are considered to be due to the transitions L 23 -M 1M1(N = 6) and L23-M 1M1(N = 5), respectively,
where the number N indicates the degree of the M23-shell ionization in the initial state. Stolterfoht
et a1. 5) have also found Auger peaks corresponding to the transitions L23-M 1M1(N = 4) andL23-M 1M1(N = 5). The isolated peak corresponding to the L 23-M 1M1(N = 6) transition was observed
for the first time in the present measurement. The broad peak may be ascribed to thesuperposition of many transitions, such as L23-MIM2iN = 5, 4, 3, 2, 1, 0) and L23-M23M23(N = 4, 3, 2, 1, 0).
The present measurement shows that the high-resolution Auger spectroscopy for heavy-ion
atom collisions is a powerful method to determine the energy levels for multiply-ionized atoms.

References
1)

M.E . Rudd and J .H. Macek: Case Studies in Atomic Collisions, North-Holland/American

2)
3)
4)

Elsevier, p. 46 (1974).
A. Yagishita and T. Nakamura: IPCR Cyclotron Progr. Rep., 14, 143 (1980).
L.O. Werme, T. Bergmark, and K. Siegbahn: Physica Scripta, B., 149 (1973).
F.P. Larkins: J. Phys. B, 4, 1 (1971).

5)

N. Stolterfoht, D. Schneider, and H. Gabber: Phys. Lett. , 47A, 271 (1974).

77

III-2-5.

Argon l-MM Auger Spectra in Arn + +Ar Collisions (II)Energy Dependence of the Auger Spectra

T. Matsuo , J. Urakawa , A. Yagishita,
Y. Awaya, T. Kambara, M. Kase,J. Takahashi, and H. Kumagai

The energy distributions of Ar L-MM Auger electrons produced in Ar 3+ + Ar collisions havebeen measured at collision energies of 5.3, 1l.5, and 14.3 MeV . The projectile ions wereaccelerated by the RILAC. The measurement was made in the energy range from 80 to 340 eV ,scanning with 0.52 eV step interval. The Auger spectra obtained are shown in Fig. 1, where
the continuous background underlying the Auger spectrum was subtracted. The lines above
spectra indicate the Auger electron energies calculated by Larkins. l ) The identification of theAuger peaks has been discussed in the preceding report. 2) We discuss here about the energy
dependence of the distribution of the Auger electron energy . They are characterized by isolated
peaks, located at 101 and 112 eV , and by broadened structure extended through 120 to 250 eV.
It is notable that the intensity of the L23-~IIMl (N = 6) peak becomes weak as the collision energy
is increased, while the broadened structure between 120 and 250 eV is enhanced. Besides, aremarkable structure can be seen in the energy range from 200 to 250 eV. This structure can not
be identified as due to the L23-MM transitions, because the multiple-ionization of the M-shell causes
the L 23 -MM Auger spectrum shift to the lower energy. They are considered to be due to the Auger
electrons resulting from the LI -shell vacancy. In the Auger electron spectrum by electron impact,
L 23 - MMCN)
L 1- M1M 1CN)
6 5 4 3 2 1 0
I I I I I I I
L 1 - MI M23 ( N)

5 4 3 2 1 0
I

I

I

I

I

I

0
I

100

150

200

250

L l -M 23
M23 CN)

300

:::
c
::::J

-e

"l

~
(f)

c

2

..s
100

150

200

250

300

Energy distribution of electronsFig. 1.
ejected in Ar 3+ + Ar collisions, measured
at 132 0 with respect to the direction of
the ion beam and with incident ion
energies of 5.3 , 1l.5 , and 14.3 eV.
The intensities of the spectra arenormalized with the number of incident
ions and the target pressure. The lines

100

150

200

250

El ec tro n energy ( eV )300

above spectra indicate the L(MM(N)transition energies calculated by Larkins.

78

no significant peak has been observed in the energy range between 220 and 300 eV, corresponding
to the transition energies of the Ar L(MM Auger electrons, because of the high Coster-Kronigtransition probability for filling of a 2s-vacancy by a 2p electron. Here, it should be noted thatas the degree of ionization (N) in the M-shell increases, the L 1-L 23M Coster-Kronig transition
process becomes energetically forbidden. Larkins have also predicted that the L(L 23M23 CosterKronig process can not occur for N > 3, and the L(L23Ml process for N > 2. In the figure, theenergies of the L 1 -MM Auger electrons calculated by Larkinsl) are also indicated. The spectrum
between 200 eV and 250 eV is well explained by the Auger process resulting from the Ar L(shellvacancy production with simultaneous ionization of the M-shell.

References
1)

F.P. Larkins: J. Phys. B,.±, 1 (1971).

2)

A. Yagishita, T. Kambara, M. Kase, T. Tonuma, T. Matsuo, J. Urakawa, J. Takahashi,
H. Kumagai, and Y. Awaya: p. 75 in this report.

79

1II-2-6.

Argon l-MM Auger Spectra in Ar"+ +Ar Collisions (III)Structure of Argon L-MM Auger Spectra in 21 MeV Ar4+
Impact on Ar

1. Urakawa, T. Matsuo, A. Yagishita, Y. Awaya,
T. Kambara, M. Kase, 1. Takahashi, and H. Kumagai

Some studies have been made for the L-Auger electrons in Ar 3+ + Ar collisions with incident
energies from 800 keY to 14 MeV, using the heavy-ion linear accelerator (RILAC).1),2) It has
been shown that many satellite lines resulting from multi-vacancy states appear dominantly. This
indicates that several electrons are ejected from M23 -shell, once L-shell electrons are ionized.
When the outer shell is partly stripped, a large number of different vacancy states are created. But
when the outer shell is more and more stripped, the number of states produced becomes limited.
For example, two isolated peaks corresponding to the transition L 23 -M 1M1(N) were observedin Ar 3+ + Ar collisions with the incident energy of 4.3 MeV (see Fig. 1 in Ref. 1), where N takes
the values of 6 and 5, and indicates the degree of M23 -shell ionization. This result is consistent
with that calculated by Larkins. 3)
The strong Argon L 23 -Auger yield is expected to be induced by the projectile with the same
velocity as the orbital velocity of the L 23 bound electrons; corresponding energy for Argon ion is
21 MeV. Furthermore, the strong electron stripping of the outer shell is expected to be producedby sufficiently heavy projectiles such as Argon ion. Since the target atom is set in motion by
the recoil, Doppler broadening of target Auger line is induced. The Doppler broadening is also
expected to become narrow as collision energy increases, because the recoil velocity of the target
atom is calculated approximately as

z·z

'e 2

vt(b) =--t~P--(2m IE )1/2,
m t· b
P P
where Z t(m t) and Zp (m p ) are the atomic numbers(mass) of the target and projectile ions,.
respectively, b is the impact parameter and E p is the projectile energy.4) Therefore, in order toobtain the detailed structure of the isolated Auger lines L 23 -M 1M1(N = 6, 5), the spectrum inthe 21 MeV Ar4+ + Ar collision was measured in the energy range from 90 to 156 eVa to. 13
eV step. The experimental apparatus, procedure and condition have been described previously.1),2)
The measured spectrum is shown in Fig. 1. It is clearly seen that the L23 -M 1M 1(N = 6, 5, 4)
peaks are devided either into a few sharp peaks or broad ones (compare Fig. 1 in Ref. 1).
Two sharp peaks of the L23 -M 1M1(6) are positioned at 100.3 eV and 102.7 eV, and theintensity ratio between them is about 2: 1. They are considered to correspond to the transitions
toward the final state Ar 8+(l s22s22p 6)lSo from the initial vacancy states Ar 7+(1 s22s22p 5 3s 2)L 3 3/2) and Li 2p 1/2)' respectively, because the ratio of the peak intensity is almost the same asthat of the degeneracy(2J + I) between the initial states, and the energy splitting of 2.4 eV isnearly equal to the difference between the L 2 p 1/2) and L 3 p 3/2) binding energies (2.1 eV for

ep

e

e

80

1.6
L 23 - M1 MJ (6)14
L 23 - M1 M1 (5)A1
1.2
L 23 - M1 M1( 4 )

A2

B1

is

.--<

X
({)

0.8

c
:::J
0

0

0.6

0.4

Fig. 1.
Argon L-Auger electron spectra
produced by 21 MeV Ar4 + bombardment

0.2

on Argon. The notation L23-M 1M1(N)090
Ele c tr on en ergy

( eV)

denotes single L 23-shell and Nth degreeM23-shell vacancies in the initial state.

neutral Ar).
The structure of the L 23 -M 1M1(5) is complicated because of the superposition of many
Auger transition lines stemming from various multiplets of the initial and final states in theL23 -M 1M1(5).
The structure of the L23 -M 1M1( 4) is more complicated than that of the L 23 -M 1M1(5).
This complexity is induced by superposition of many Auger transition lines stemming from double
L-shell ionization and various multiplets of the initial and final states for the L 23 -M 1M1(4)transition (refer to Ref. 3). In the energy range between 128 and 156 eV, there is a broad"humps" in addition to the broad Auger peaks. It is tentatively attributed to a superposition ofmany weak Auger transition lines stemming from double L-shell ionization in addition to several
Auger transition lines (L 23 -M 1M2l5), L23-MIM23(4), L23-M23M23(4)).
Table 1 shows a partial list of measured line energies of designated Ar L-Auger electronsobserved in the present work. The line energies of L 23 -M 1M1 (N = 6, 5) transitions measured by
us are smaller than those calculated by Larkins with the discrepancy of about 3 eV, but the line
energy of L23 -M 1M1( 4) transition agrees well with that calculated by Larkins. Results of
Larkins for the line energies of L23-M23M2lN) transitions agree well with that of L2fM23M23(0)transition measured in electron impact on Argon for N = 0 and those of L23-M23M2lN)
transitions measured by Stolterfoht et a1. 5 ) for N = 4, 3, and 2. These Auger electron energies
decrease linearly with an average shift of 11 eV per degree of M23-ionization. But the line
energy of L23 -M 1M1(0) transition is larger than that calculated by Larkins with a discrepancy of
about 10 eV. Using the experimental energy values of L23 -M 1M1(0) transition and L23-M 1M1(N = 4, 5, and 6) transitions, the average shift per degree of M23-ionization for L 23 -M 1M1(N)transitions is derived to be 13 eV on the assumption that the Auger electron energies of
L23-M 1M1(N) transitions decrease linearly with degree of M23-ionization.

81

Table 1. A partial list of measured transition energies of designated Ar L-Auger electrons
produced by bombardment of Ar with 21 MeV Ar4+. For comparison the transitionenergies calculated by Larkins 3) are also included. The "peak label" refers to Fig. 1.
Values on the left in line energy are weighted averages for peaks of L23 M1M1(N)transitions.
Peak label

Line energy( e V)

Tentative assignment

Larkins( e V)

100.3
104

101
102.7
110.3
112

115
113.2

125

12l.6
124.2
126.3

126

Ar 5+(2 p 5

eP 3/2) 2

3s 3p2)(IS)-7 Ar 6 +(3 p 2(lD))

ep 1/2)The uncertainty of the electron energy is estimated to be less than ± 0.2 eV.

References
1)
2)
3)
4)
5)

A. Yagishita, T. Kambara, M. Kase, T. Tonuma, T. Matsuo, 1. Urakawa, 1. Takahashi,
H. Kumagai, and Y. Awaya: p. 75 in this report.
T. Matsuo, 1. Urakawa, A. Yagishita, Y. Awaya, T. Kambara, M. Kase, 1. Takahashi, andH. Kumagai: p. 77 in this report.
F. P. Larkins: 1. Phys. B,.±, 1 (1971).
R. Mann, F. Folkmann, R. S. Peterson, Gy. Szabo, and K - O. Groeneveld: ibid., il,3045 (1978).
N. Stolterfoht, D. Schneider, and H. Gabler: Phys. Lett., 47A, 271 (1974).

(3p)

82

III -2-7.

Angular Distribution of Sn lX-Rays

J. Takahashi, A. Hitachi,* Y. Awaya, H. Kumagai,
T. Kambara, M. Kase, T. Tonuma, and A. Yagishita

We have studied the mUltiple ionization of inner shell electrons by measuring emitted X-rays
with high resolution, systematically.1) Ionization probabilities PLand PM were derived from theseexperiments, and the reduced parameters to fit the universal curve were ootained. In this analysis
it was assumed that satellite X-rays were isotropic because Jamison and Richard 2) had shown thatthe polarization of KL X-rays from Al target bombarded by He or Li ions was smaller when theincident energy was larger. In order to study this point, we measured the K X-rays from Ti target
excited by 82 MeV N 7+(5.9 MeV /amu) with a broad range X-ray crystal spectrometer 3) and foundthat the satellite X-rays were isotropic. 4 ) There is no report on L X-rays emitted after the multiple
ionization, therefore, L X-rays of Sn have been measured by the broad range X-ray crystal
spectrometer and a Si(Li) detector. This report gives an analysis of the experimental results.
Target was a self-supporting metallic foil Sn(l Mm). It was excited by 82 MeV N 7+ ion beamfrom the cyclotron. Typical spectrum obtained by the Si(Li) detector for Sn L X-rays is shownin Fig. I with X2 -fitting by the F ACOM M200 computer. The spectrum was divided into 5
peaks assuming a gaussian form. Main components of the peaks are Le, La' L~l' L~2+ 15' L 2 ,3'respectively, and peak positions are shifted to higher energy side owing to the multiple ionizationof M shell electron. Weak lines are included in each peak. Arrows indicate energies of the lines
(a)

( b)
~

j

(b) Sn L
X- raysI

1
itJ'J'J'

10
10 3

i

'"0,......

;

X
~
c:

(f)

C

.5 10

"'-

::::l

::::l

U

::s:::

2

u

U

.J

Vf

I"

~

~
\

I
J

5

0

_ -..ltl

1

-..l

•

~

,!

0
10 1

5.0
Energyo250
Channel number

Fig. 1.
(a) Sn L X-ray spectrum obtained by the Si(Li) detector at 25°. Incident
beam was 82 MeV N 7+. eu K~ and Kt3 peaks may be due to the scattering froma copper part in the chamber. (b) Solid curves are X2 -fitting by the computer.
* Present address: University of Notre Dame.

83

S i (L i )

0.48
0.46

>.

.~

~
<l>

'"
w

n:::

0

Q

I

La,

0
0

1

0

0

6

6

c,

~

~

0

1.2

CJ

~ 0.33oooc2c 0.11

0

1.0 -

0

0

035

1.4

>

0

;
60

30

120

90

150

0.09 -

I

ZS

0

t:::.

0

L"I

2S Lpz.l S

(IJ

Q)

Ang len:::(Deg )

0.06

Angular distribution of total
Fig. 2.
intensity normalized by measurementof another Si(Li) detector at a fixed angle

0. 04

\l

-v----"V

S7

<;'

'V

i -e

-e-e

o

(90°) and corrected for self-absorption

180
An gleusing the absorption coefficient of Len'e LTz. 3Ll( Deg. )Fig. 3.
Angular distribution of eachpeak in Fig. 1, relative to the total
intensity.

3.0

x
2c
:::J

o

U

1.5

o

3.50

3.45
Energy( keV )

Fig. 4.
Sn La X-ray spectrum obtained by the broad range X-ray crystal
0spectrometer at 70 • Incident beam was 82 MeV N 7+. The spectrum isdivided into 6 groups: LM°O' 1, LMl, LM2, LM3, LM4, and LMocx 2, by dottedlines , where LM x denotes the initial state which has a vacancy at L3 shelland x vacancies at M shell. The configuration (2p) - 1 (3 f ) -X denotes theinitial state which has a vacancy at 2p shell and x vacancies at 3 f shell(1 = s, p , d).

84

without multiple ionization. S) ,6) Figure 2 shows the angular dependence of the total intensity
which is normalized by the measurement of another Si(Li) detector placed at a fixed angle (90°).
It is seen that total intensity is high at 155° and low at 25°. A study on why intensity changes
with the observed angle is in progress. The relative intensities of each peak to the total intensity
are shown in Fig. 3. They do not change with angle within experimental errors.
Typical spectrum of L~ X-rays obtained by the broad range X-ray crystal spectrometer isshown in Fig. 4 with transition energies calculated using the computer program of Herman and
Skillman. 7) Actually, the multiplet from an initial and final state configuration and presence of
vacancies at N shell may broaden a peak. Since each transition is not resolved and does notalways agree with rather broad peaks obtained experimentally , the spectrum is divided into 6
groups: LM&, LM1, LM2, LM 3 , LM 4 , and LM&2' as shown by dotted lines. The integrated countsof each group relative to the total counts of La X-rays are plotted as a function of emitted photon
angle in Fig. 5. All intensity groups are constant within experimental errors.

Cr ys t.

0.30
0.28
0.21
>-

0.19

(j)

c

2c

~ 0.15f
Q)~

L M~ ,~---~--------~~--

o

013

0:::
\l

\l

LM4

0.05

-I

0.03

-1:--~- X-- x -- X -

IJ

\l

x

-v-

LM~

o

180

Fig. 5.

Angular distribution of eachintensity group in Fig. 4, relative to thetotal La intensity.

Angle ( deg )References
1)

Y. Awaya: "Electronic and Atomic Collisions", (Ed. by N. Oda and K. Takayanagi),
North-Holland Publishing Co., p. 325 (1980).

2)
3)
4)

K. A. Jamison and P. Richard: Phys. Rev., 11,1642 (1978).
A. Hitachi, H. Kumagai, and Y. Awaya: Nucl. Instr. and Methods, 165,631 (1982).
A. Hitachi, Y. Awaya, T. Kambara, M. Kase, H. Kumagai, T. Tonuma, and A. Yagishita:
RIKEN Accel. Progr. Rep., 12, 69 (1981).

5)
6)
7)

J. A. Bearden: Phys. Rev., 39, 78 (1967).
J. H. Scofield: Atomic Data and Nucl. Data Tables, 14, 121 (1974).
F. Herman and S. Skillman: "Atomic Structure Calculations", Prentice-Hall Inc., Englewood
Cliffs, New Jersey (1963).

85

III -2-8.

Production of Highly Charged Ions by Heavy-Ion
Bombardment of Rare-Gas Targets

T. Tonuma, M. Kase, T. Matsuo, 1. Urakawa, 1. Takahashi,
H. Kumagai, T. Kambara, I. Kohno,
S.Ozk6k,* and Suck Hee Be

An experimental apparatus to measure secondary ions produced in collision of heavy ionswith gaseous targets has been reported. 1) The apparatus was newly set up in order to carry out
the experiment uSIng the beam from the heavy-ion linac. The exhausting system and the analyzer
magnet were improved. The apparatus is evacuated by a 5000 f/sec cryo pump and a 220 f/sec
turbo molecular pump. The background and operating pressure were 7 X 10- 8 Torr and
1.3 X 10- 6 Torr, respectively.
A schematic diagram of the apparatus is shown in Fig. 1. A heavy-ion beam crosses a
gaseous target emerging from a gas jet and ionizes gas atoms. Ionized atoms, namely secondaryions, are extracted perpendicularly to the beam direction by an electric field applied between theparallel plate electrodes and are focused on a detector by an Einzel lens and the analyzer magnet.
The secondary ions are detected by a channeltron and the output signals are amplified andintegrated by MCS(multi-channel scalar) through a SCA circuit. The charge states of the ions areanalyzed by scanning the magnetic field.
Figure 2 shows a charge-state spectrum of secondary Ar ions produced by 37 MeV Ar4+
ion-bombardment. The size of beam spot was 1 mm wide and 2 mm high on the target and thebeam current was about I nA. The electric potential was kept at 2 kV throughout themeasurement. The channel advances with 15 nC of integrated beam charge on the Faraday cup.
The peaks corresponding to Arl+ and Ar2+ have fine structures caused by the beam fluctuation,
which will have to be improved.
Gas jet~Pa ralle I plateelectrode

Faraday c up
Heavy-ionbeam-----~---t~-------

s=

--I=

Einze llens -

Fig. 1.
* Permanent address:

Secondary ions=-

Schematic diagram of the apparatus.

University of Istanbul Nuclear Physics Dept., Istanbul, Turkey.

86

X 10 5

I

I

I

1

-

3.94r-

1+

3.28 '-

Ar

H( 37 MeV ) +Ar

-

~I

6+
2.62 -

-

7+

Q)

c:
c:
<U
..c:

<
1.97.8
c:

X64
-

8+

::l

o

o

-

1.31-

0.66'Jo4+~ A !I\

64

128

3+
{l,
}\

1/
192

256

\

1

320

Channel number

Fig. 2.

Charge-state spectrum of the secondary Ar ionsproduced by 37 MeV Ar4+ ion-bombardment.

Reference
1)

T. Tonuma, A. Yagishita, M. Kase, T. Kambara, Y. Awaya, H. Kumagai, and I. Kohno:
RIKEN Accel. Progr. Rep., 15,72 (1981).

87

III -2-9.

Mechanical Design of Apparatus to
Measure Secondary Ions

T. Tonuma, T. Chiba, and A. Yagishita

The apparatus was designed and constructed to have an experimental study of secondary ionsproduced by heavy ion bombardment on rare-gas targets. The mechanical layout of the apparatus
is shown in Fig. 1. The apparatus consists mainly of a gas nozzle, parallel plate electrodes, an
Einzel lens, an analyzer magnet and a detector part. The gas nozzle has multi-capillary jet whose
inside diameter is 1 mm. It can be moved up and down to set the optimum condition. The
parallel plate electrodes are arranged to have a distance of 2 cm between them and one electrodeis provided with a slit 2 mm wide and 6 mm high for the extraction of ions. The gas nozzle isinserted between the electrodes. The Einzel lens consists of three plates which have slits of
12 mm X 12 mm and is used to focus the secondary ions on a detector. The chamber itself ismade of stainless steel and the electrodes and the lens are made of molybdenum. The
characteristics of the analyzer magnet are as follows: 3 cm of pole gap, 18 cm of effective radius,
60° of deflection angle and 16.1 ° of entrance and exit angles which focus the ions vertically andhorizontally. Maximum magnetic field is about 6 kG. A quartz support is used to adjust theposition and the size of the beam spot. The chamber is evacuated with 5000 i/ sec cryo pump
and a 220 f/sec turbo molecular pump.
Gas Inlet

LJ

lr

I
Cryo Pump

I I

'il

Viewing

Port
Quart zSupportGas
Inlet

Channeltron

Box

Fig. 1.

Layout of the apparatus.

88

III -2-10.

Scan Controller for Secondary Ion Experiment

M. Kase, H. Kumagai, T. Tonuma, and K. Nishi

A scan control circuit for the secondary ion experiment has been developed. For theexperiment, one has to change accurately the extraction voltage or the magnet current by finesteps remotely from the measurement room which is at a distance of about 70 m from theexperimental area. In order to minimize the number of signal lines between the two places andto eliminate the noise disturbance on the signal lines, a pulse-counting method is employed. The
principle is shown in Fig. 1. The scan controller sends a series of pulses (0.6 msec width, 400 Hz)
to the power supply system via a 70 m signal line. The power supply system has a binary counterand a 16 bit digital-to-analog converter (DAC). The DAC provides the power supply with thereference dc voltage, V ref, a magnitude of which is proportional to the total number of pulses
stored in the counter. The output (a high voltage (up to 5 kV) in the case of the voltage scanor a constant current to the analysing magnet in the case of the field scan) is obtained according toVref- One can set the initial condition, Ni , the final one, N f , and the step width, ns. The
measurement period, t m , for each step is determined by the integration of the beam current on
a target.

r -- ---- - - -- - ---- - - --- -,

~
I1 s
I ~

I

I

I

I

ns N, Nr

I
I
I

I
I
I

~~.----~~~~~~~E~~~~ - -- --------- -- --- -- --~Outp utI-~ - ---

-

I

----

I ~--- -- - ----;I

Meas ur ement room;---__-----'-7 0=-m~_lIr____j Exper ime nt al ar ea

A block diagram of the scan controller. n s' Ni' and Nf are
Fig. 1.
presettable and step up signals come from a current integrator.

89

III -2-11.

Analysis of F K a - Emission Satellite Spectra from
Fluorine Compounds by the DV-Xa Method

K. Fujima, K. Fuwa, and M. Uda

The difference in valence electron nature of various fluorine compounds has been clearlyobserved in their F K-a emission satellite spectra. The energies of satellite peaks do not changewith the change in the fluorides and agree well with the atomic values estimated by several
computational methods.1)'2)'3) However, their satellite intensities change owing to the differencein valence structure. This fact can not be interpreted from the atomic nature.
Intending to analyse these features, the DV -XQ! cluster method has been applied to NiF 2'
CuF 2' and NaF clusters as the representatives for the fluorides.
The results obtained show that in the molecular orbital scheme, the valence orbitals of the
F atom lower their energies and are localized by the strong attractive Coulomb potential causedby the K-hole. As a result, the F atom should have an atomic nature in the ionized state, even
if it is buried in a solid. This is also true for the multi-ionized state and leads to the fact that thesatellite peak positions do not change even when there exist the difference in chemicalsurroundings of the F atom.
Once this atomic nature is realized, the K-emission intensities, calculated by means of thedipole approximation, are the same for all the fluorides. This atomic state is thought not to havea chance of relaxation through radiative nor non-radiative process, which may alter the satellite
intensities.
By the way, KVV -Auger probability has been reported to be sensitive to the valence
relaxation immediately after the K-ionization. 4 ) Since Auger process is the competitive process of
K-emission, the intensity of satellite might be influenced through this first excitation process.
Our present calculation has been encouraging because it shows that the charge distribution
soon after the K-ionization decreases the intensity of satellite peaks and enhances that of themain peak. The figures illustrated below show the charge distribution of NiF 2 cluster in the
ground state (a), soon (b), and long enough (c) after the K-ionization. The charge distribution(c) no more radiates the photon of satellite energies but radiates that of the main peak.

(a )Fig. 1.

The charge distribution of NiF 2 cluster in the groundstate (a), soon (b), and long enough (c) after the K-ionization.

90

References
1)
2)

Z. Horak: Proc. Phys. Soc. London Sec., A77, 980 (1961).
E. H. Kennard and E. Ramberg: Phys. Rev., 46, 1040 (1936).

3)
4)T. Aberg: Phys. Lett., 26A, 515 (1968).
O. Gunnarsson and K. Schouhammer: Phys. Rev. B, 22, 3710 (1980).

o91

III -2-12.

Determination of Electron Contact Densities
for Outermost

Electrons in Tin Compounds

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

The experimental evidence of the influence of chemical environment on outer-shell internal conversion in
119Sn was reported in the previous report. 1) In the present report, we describe about electron contact densities
for the outermost electrons in white tin and CaSn0 3 .
Internal conversion sources were prepared by implantation of radioactive 119Sb (T 1(2 = 38.0 h) using theelectromagnetic isotope separator at Cyclotron and Radioisotope Center, Tohoku University. Detailed
descriptions on the preparation of two sources were given in the previous report. 1)
In order to assign the final chemical state of the conversion sources, the Mbssbauer effect in the 23.87 keYtransition of 119Sn was measured with a CaSn0 3 absorber. In Fig. 1 there are shown the emission Mbssbauer
spectra obtained from the implanted white tin and CaSn0 3 samples together with the transmission spectra
obtained from the measurements with a transmission geometry using a standard source Ca 119mSn03. In the caseof white tin, the emission spectrum could be clearly fitted with a single line at {) = - 2.48 mmls which is in good
agreement with that of the transmission spectrum (Fig. 1 (a)). This means that the implanted 119Sb atom occupies
the normal lattice point of tin in the metal. On the other hand, in the case of CaSn0 3 , a more complex spectrum(a )Whit e tin
Emiss ionTransmi ss ion

§ 100
If)
If)

E

~

~

92

OJ

>

(\J

84

OJ

0:::

- 8 -6 -4 -2 0 +2 + 4 +6 +8-8 - 6 - 4 -2

Veloc it y~

Emiss ion(mm / s)Tr ansmission

c
0

If)

.'!2
E

If)

c
~

92

OJ

:::

~

84

OJ

0:::

Velocity

Fig. l.

(mm / s)Mbssbauer spectra obtained from the sources of 119Sb

implanted into white tin and CaSn0 3 with a CaSn0 3 absorber(emission). For comparison there are shown the ' transmission'
spectra taken with a standard Ca 119mS n0 3 source and absorbersof white tin or CaSn0 3 .
* Faculty of Science, Tohoku University.

92

was observed as shown in Fig. 1 (b). The emission spectrum of CaSn0 3 sample could be decomposed to threeabsorption peaks. Line A corresponds to the normal substitutional site in CaSn0 3 because a similar consideration
as in the case of white tin mentioned above can be applied (see the transmission spectrum in Fig. 1 (b)). Line B
may be attributed to the quadrupole doublet of Sn(lI) on the basis of the fact that its isomer shift and quadrupole
splitting are close to those reported by Boyle et a1. 2) for the tetragonal or orthorhombic SnO. The number of
119Sb atoms in the site A was estimated from the temperature dependence of M6ssbauer spectrum as 47 %.
The conversion-electron spectra were measured with a 50 em, double focusing, iron-free ~-ray spectrometerat the IPCR. Detailed procedure for measurement of conversion electrons was described in the previous report. l )The analyses of the conversion spectra were carried out using the computer code ACSEMP. 3) The internal°°conversions of shells which correspond to the internal conversions of 5s and 5p electrons, could not be resolved
at all into subshells (° 1, OIl' and Om)' However, since the contribution of 0n,III conversion to the total
conversion of shells was estimated to be less than 5 % for the M 1 transition, it was neglected in the analysis.
In order to deduce the accurate intensity of the O-lines, the contribution of the K-LM Auger lines of tin which
superimposed on the N-, and O-lines in the same momentum region was subtracted as an Auger-backgroundobtained by an independent measurement using radioactive 117mSn.
Results of the analyses for two different sources are listed in Table 1 and the conversion spectra are shownin Fig. 2. Here, since the M6ssbauer spectrum indicated that only 47 % of the 119Sb implanted into the hostmaterial was in the form of CaSn0 3 for the source of CaSn0 3 , the O/N I intensity ratio was corrected on theassumption that the conversion intensity of site B was equal to that of white tin from the equality of the isomer
shift. The 5s electron density at the nucleus, that is, the so-called electron contact density can be deduced fromthe observed O/N I ratio by using the formulawhere I l/J 4 s (0) 1 2th eOf. is the theoretical 4s electron density of the tin atom. The observed electron-density
difference between white tin and CaSn0 3 was larger than that observed by Bocquet et a1. by a factor of 2.5 in

~
C

:::J

C 10 2

~

-2
«

I

/
/
/

I

-8

/
/

C
:::J
0

/
/
/

U

10 1

I

/

Fig. 2.
Conversion electron spectra fromtwo different 119Sb sources of white tin and
CaSn0 3 . The curves have been normalized to
22 500Pot enti ome ter setting

23000

equal NI line intensity.
o white tin, • CaSn0 3

93

Table 1.

Relative intensities of NI and°lines from the internal conversion of the 23.87 keY M I

transition in 119Sn for two well-defined chemical forms, the forms of white tin and CaSn0 3·

o (mm/s)

Chemical form

CaSn0 30.0197 ± 0.0232

14.2 ± 16.7

oWhite tin

0.l01 ± 0.10

72.7 ± 7.3

2.48

6. \ ljISs(O) \2a)= 58.5 ± 18.2 a.u.

11/I4s(0) 12 = 719.65 a.u. is assumed.

its magnitude. 4 ) It was found that the 5s electron density at the nucleus is about 80 % smaller in CaSn0 3 thanin white tin.
For the estimation of the occupation umbers of the electrons in the valence shell or of the electronic
configuration of the valence electrons, it seems to be a simple and useful approach to renormalize the atomic
wave functions within the Wigner-Seitz sphere, as described by Friedman et al. 5) In this approach one utilizes thefree-atom wave functions, truncates them at the radius rws of the Wigner-Seitz sphere, and renormalizes themwithin this sphere, thereby preserving charge neutrality. This approach makes it possible to take into account the
problem of the charge compression or the size effect of atoms in solids, at least approximately. According toFriedman et aI., the renormalization factor N is represented as=0r > r ws

The renormalized-atom ratio of the contact densities between 4s and 5s electrons for Sn 5s 2 5p2 is

If this ratio is compared with the observed value of the O/N l ratio for white tin in the present work, 0.101 ± 0.016,
the occupation number of the 5s subshell of white tin is 1.68 ± 0.28. In the same fashion, the configuration for
CaSn0 3 is estimated to be 5s0.39 5 p 3.61 by using a free-atom ratio for Sn in the configuration 5s5 p 3, 0.047, andN=~

References
1)

H. Muramatsu, T. Miura, H. Nakahara, M. Fujioka, E. Tanaka, and A. Hashizume: RIKEN Accei. Progr.
Rep., 12,51 (1981).

2)

A. 1. F. Boyle, D. St. P. Bunbury, and C. Edwards: Proc. Phys. Soc. (London), 79, 416 (1962).

3)
4)

M. Fujioka, M. Takashima, and M. Kanbe: Z. Phys., A299, 283 (1981).
J. P. Bocquet, Y. Y. Chu, 0. C. Kistner, M. L. Perlman, and G. T. Emergy: Phys. Rev. Lett., 17,809(1966).

5)

R. M. Friedman, R. E. Watson, 1. Hudis, and M. L. Perlman: Phys. Rev. B, B., 3569 (1973).

94

III-2-13.

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

S. Kohmoto, M. Ishihara, T. Nomura,
Y. Gono, and Y. Itoh

A nuclear-polarized ion beam with a kinetic energy in MeV range was generated by the tilted
foil method 1),2) and the degree of nuclear polarization was determined.
In Fig. I, an ion beam passes through a thin carbon foil (foil I) whose normal is tilted
relative to the beam direction (¢ 1= 0°). The ions are not only excited but also polarized atomicallyat the exit of the surface of the foil due to the non-cylindrical symmetry. This polarization istransferred to the nucleus via the hyperfine interaction during the flight. The detection of lightemitted from the ions after passage through the second thin foil (foil II) placed perpendicularly
to the beam direction (¢ = 0°) is the proof of the transfer of the polarization: atom -+ nucleus -+atom, because a cylindrical symmetry is kept at the foil II.

fOCh i;Qf ~o;::e.~/"'c.JJCo0

C foilPola rizer

I

Filt~

Fig. 1.
Schematic experimental arrangement. Photons are observedin a direction perpendicular to the beam aixs and to the normal of
the tilted foil.

14N ion beam of 5 MeV kinetic energy was produced in the Linac Accelerator. The two
carbon foils were of 5 Ilg/cm2 thickness and the tilt angle ¢ of the foil I was 50°. The polarizationof light emitted from the ions downstream from the foil II was determined with a rotating A/4
plate followed by a fixed linear polarizer (~ = 0°), an interference filter and a single photon
counting photo-multiplier (PM) with low dark counts. Another PM was set at the other side of
the apparatus for the purpose of normalization. The atomic transition selected by the filter was
Is 26f2P - Is 27g 2G 494 nm. The relative Stokes parameter SII averaged over the fine componentsof the transition which were not resolved in our experiment was obtained measuring the intensity
l' for /3 = ± 45° , i.e.

95

The result was SjI == 0.7 %. From this value, we deduced the nuclear polarization PI == 3 %, using
the relation 3) between SjI and PI. Of course, we have verified that the Stokes parameter SjI simply
changes the sign but not the absolute value when one changes the tilt angle QJ to -QJ. Although
our PI value should be taken to give only the rough magnitude because, for example, we have chosen
the distance between two foils (1.5 cm) rather arbitrarily, we emphasize that it is the firstobservation of PI in the MeV energy range.

References
1)

B.I. Deutch, F. Q. Lu, and J. Y. Tang: Hyp. Int., 9, 169 (1981).

2)

S. Kohmoto, M. Ishihara, T. Nomura, Y. Gono, and M. Sasagase: RIKEN Accel. Progr. Rep.,Ii, 86 (1981).

3)

H. J. Andra, H. J. Plohn, A. Gaupp, and R. Frohling: Z. Phys., 281, 15 (1977).

96111-2-14.

Effects of Chemical Bond on 0

Ka Spectra from

Multiply Ionized States

M. Uda, K. Maeda, Y. Sasa, A. Koyama,
and S. Nakamura

For a wide range of target atomic numbers, effects of chemical bond on intensity
distributions of X-ray satellites arising from multiply ionized states have extensively been
investigated.1) Their intensity distributions have changed dramatically in X-ray emission related totransitions between inner shells and valence bands with the difference in the chemical bonds formost of the chemical compounds. 2)-5) 0 Ka X-ray spectra are, therefore, also expected to show
similar effects on their intensity distributions.

o Ka satellite spectra have been observed in a previous paper. 6) Their intensity distributions
should differ for different methods of ionization and species of chemical compounds. The former
gives difference in the ionization cross sections for multiply ionized states. The latter gives rise
to difference in the electronic rearrangement in the valence band prior to X-ray emission.
C3+ ions were accelerated up to 2.8 MeV by the Tandetron (General Ionex Corp.). White
X-rays generated from Rh anode were also used, for the comparison, to emit 0 Ka: X-rays.
Specimens used here were MgO, MgSO 4' CuO, and CU 2 O.

o KG' satellite spectra were energetically analyzed with a RAP flat single crystal (010). The

results are shown in Figs. 1-4 K lL n denotes the emitted X-rays from the initial state with one
and n vacancies in K and L shells, respectively. From the comparison between the spectra induced
by C 3 + and those by white X-rays, change in the electronic rearrangement might be deduced.
Analytical treatment for this is in progress.

~~-...,J

-~

~
~

o Ko

0 Ka

I

I

I

(MgS04 )

(MgO)

e ••

.'

,,

'.

'.

>-.

e

"

.........' :

~

;" :,

C3+

,,

i

en
c

:

I,

...--.-..

'0c ..... ·
C1I

••••

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

'.

.....

.';""',

'

'

'<

.~:.

....,
,

,.:",,~.,,;:'
... .

X-ray

..,

..""'-"~..,.-~#
I

I

I

I

I

I

520

525

530

535

540

520

energy (eV)Fig. 1.

••e'. .. . .. .

....

'.

....- :.

....-

+-

:

.'

."

o Ka satellite spectra of MgO.

Fig. 2.

I

I

I

525

530

I

535

540

energy(eV)°KG' satellite spectra of MgS0

4

•

97

o Ka
(CuO)

....

.. '."' ..

...

....'
I"

• \

'. '

.

.2:

..

:'

•••••

,
,.,

to

Qi
L..

.'

. '..

;'\

....

.. ' .:'t .'-::.. '.:-. .~"
ell

.'

,

...' ' . .

'.

.......

.' . ... .
X-ray

"

- ~-.!:....;' ..•. , .
I

I

I

I

,

I

I

I

T

I

520

525

530

535

540

520

525

530

535

540

energy(eV)Fig. 3.

o Ka satellite spectra of CuO.

energy (eV)Fig. 4.

0 Ka satellite spectra of CU 2 O.

References

1)
2)

H. Endo and M. Uda: Z. Phys. A, 306, 187 (1982).
M. Uda, H. Endo, K. Maeda, Y. Awaya, M. Kobayashi, y. Sasa, H. Kumagai, and T. Tonuma:
Phys. Rev. Lett., 42, 1257 (1979).
H. Endo, M. Uda, and K. Maeda: Phys. Rev. A, 22, 1436 (1980).

3)
4)

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

5)
6)

K. Maeda and M. Uda: Phys. Lett., 91 A, 223 (1982).
K. Maeda. Y. Sasa, K. Fuwa, and M. Uda: RIKEN Acce1. Progr. Rep., ~ 75 (1981).

981II-2-15.

Supertransferred Hyperfine Magnetic Field at

119Sn4+(+--119Sb5+) on Cr 0
2

3

Surfaces

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

In the preceding volume of this report, we presented an emission Mossbauer study on
carrier-free 119Sb5 + ions adsorbed on cx- Fe 20 3 surfaces. I) From the observation of the supertransferred hyperfine (STHF) interaction between the ordered Fe 3 + ions of the substrate and 119Sn4+
ions arising from 119Sb5+, the adsorbed 119Sb5+ ions were found to form Fe 3+- 0 2- _ 119Sb 5+ bondson the surfaces. In this period, similar measurements were made on Cr20 3 substrate.
Cr 20 3 is an antiferromagnet with the same crystal structure as a- Fe20 3 (corundum-type). Its
low Neel temperature (303 K) made it possible to study the effect of bulk magnetization ofsubstrate upon the STHF field at 119Sn nuclei arising from 119Sb5 + on the surfaces.

\.

;--

!

I

29 7 K

V
~~~\
c

.

.

'.'l.
"\

.2

t

\

if)
if)

E
c

242 K

I

\ i

V

if)

cv

~

_4~~
r'

"',",7~~"",\. Ir~~;:

5

I

if)

/
"",Ji

\

4

E
E

v

:S

3

-0
.~
(l)

c

2

~

o

-10

10

o

100

Veloc ity (mm. S - l )Fig. 1.

Emission Mossbauer

200

300

Temperature (K)Fig. 2.

Variation of the full width atspectra of the "as adsorbed:'Cr
119 Sb 5+ specimen

half maximum of the emission line ofthe "as adsorbed" Cr 20 3 - 119Sb5+ specimen

measured at different

with the temperature of measurement.

temperatures. The isomer

The arrow shows the Neel temperature

shift is given relative toof bulk Cr 20 3"

2°3

BaSn0 3 .

99

Pentavalent 119Sb (half life: 38.0 h) produced by the Cyclotron 2) was adsorbed onto Cr 20
3
powder at 100°C from a 0.25 mol dm- 3 LiC I solution of pH 3.0. The oxide was filtered,washed with distilled water, and dried at room temperature over P20S. Emission Mossbauer
spectra of 119 Sn produced by the EC decay of 119 Sb S + on surfaces of the oxide specimens wererecorded against a BaSn0 3 absorber.
Typical emission spectra of the "as adsorbed" Cr 20 3 - 119Sbs+ specimen at different
temperatures are shown in Fig. 1. The spectra consist of an unresolved emission line of 119 Sn4 + ,whose width depends remarkably on the temperature of measurement (Fig. 2). It can be seenfrom Fig. 2 that near and above the Neel temperature of bulk Cr 20 3 the emission line has a widthcorresponding to ordinary diamagnetic 119Sn4+ ions, but it is considerably broadened below thattemperature. Namely, the broadening occurs in parallel with the magnetic ordering of Cr 3+ ionsof the substrate. This observation is a decisive evidence for our view that the observed broadening
is caused by the STHF interaction of the 119 Sn4 +( *- adsorbed 119 Sb S +) ions with the magneticallyordered Cr 3+ ions of the Cr 20 3 surfaces. Thus, we can conclude that the adsorbed 119Sbs + ionsform Cr 3+ - 0 2-_ Sb s+ bonds on the surfaces as in the case of (X- Fe 20 3- 119Sbs+.
As shown in Fig. 3, the effect of heat treatments on the Cr203-119Sb5+ specimens was
similar to that on a- Fe 20 3 _ 119Sb 5+ reported previously. In the present case of Cr20 3, however,decrease in hyperfine fields was observed at higher temperatures. This is ascribable to coagulationof 119Sb 5+ ions with diamagnetic impurities on the surfaces.
Detailed description of the experimental procedures and results as well as discussion basedon a simplified surface model has been published elsewhere. 3) A similar study on ferrimagnetic'Y-Fe203 is also reported in this volume. 4)

c

.~
U)
U)

E
c

U)

m

r::

Fig. 3.

Emission Mossbauer
spectra of the 2h heat-treated
Cr 2 3 119Sb5+ specimens
measured at liquid nitrogentemperature. The isomer shift
is given relative to BaSn0 3.

°-

- 10

o
Velocity ( mm · s-

10
1

)

100

References
1)

T. Okada, H. Sekizawa, F. Arnbe, and S. Ambe: RIKEN Acce1. Progr. Rep., 12.,91 (1981).

2)
3)

S. Arnbe, F. Arnbe, and T. Okada: ibid., p. 112.
T. Okada, S. Arnbe, F. Arnbe, and H. Sekizawa: 1. Phys. Chern., 86, 4726 (1982).

4)

T. Okada, F. Arnbe, S. Arnbe, and H. Sekizawa: p. 101 in this report.

101

III -2-16.

Emission Mossbauer Studies of Dilute

119Sb Ions Adsorbed

on Ferrimagnetic Spinel Oxide Surfaces

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

Previously, we reported results of emission Mossbauer measurement of 119Sb arising fromcarrier free pentavalent 119Sb ions hydrolytically adsorbed on surfaces of antiferromagnetic oxide,
a-Fe 20 3.1) ,2) This work has been extended to a ferrimagnetic oxide with the spinel structure,'Y- Fe 20 3' The aim of these works is as follows. By observing the broadening and splitting of theemission spectra which are caused by the supertransferred hyperfine (hereafter abbreviated as
STHF) magnetic fields coming from the ordered magnetic ions of the substrates, microscopic
information on the physical and chemical states of the adsorbed ions is able to be investigated.
A Mossbauer analysis was made on the 23.8 keY 'Y-rays emitted by the first excited states of
119Sn(119Sn*, half life: 17.8 ns) arising from 119Sb (half life: 38.0 h) by the EC decay.
Experimental procedures have already been reported in previous reports. 1) ,2) Carrier-free
119'Sb ions were adsorbed on the surfaces of the ferrimagnetic oxide powders of 'Y-Fe203' the
Neel temperature of which was about 590°C. The average particle size of these acicular powders
was about I 11m as determined from electron micrographs. Adsorption of the pentavalent 119Sb
ions was made hydrolytically at room temperature. Emission Mossbauer spectra of the "asadsorbed" and the heat-treated specimens were taken at liquid nitrogen temperature against
BaSn0 3 absorber. The temperatures of heat treatments were 200, 300, 400, 500,and 600°C.
A few examples of the obtained spectra on 'Y-Fe203 and Cr 20 3 are given in Fig. 1. The spectrumof adsorbed ions on Cr 2 0 3 above its Neel temperature is also shown as the reference spectrum inwhich the STHF magnetic fields are absent. Detailed report on Cr 20 3 has been given
elsewhere. 2)'3)
Even in the "as adsorbed" specimen of 'Y-Fe203' there could be seen a remarkably broadened
emission line. The line transformed into the more broadened magnetic hyperfine patterns withthe elevation of the temperature of isochronal heat treatments. As the cubic 'Y-Fe203 is graduallyconverted to the rhombohedral a-Fe 20 3 on being heated to temperatures above 400°C, the emission
patterns of the heat-treated specimens above 400°C become complex. The distribution of hyperfine
magnetic fields (Hhf) obtained by analyzing the spectra by means of the method of Hesse 4 ) is shownin Fig. 2. The distribution of the hyperfine magnetic fields for the "as adsorbed" specimen of'Y-Fe203 is almost equal to that of a-Fe 20 3 reported previously.2) With the elevation of thetemperature of heat treatment, the high field components grew up rapidly accompanied by a slow
decrease of the low field components. This makes a remarkable contrast to the case of a-Fe 20 3·
The chemical formula of 'Y-Fe203 is also rewritten as (Fe 3+) [Fe 3+2/3 1/3 ] 04' where (Fe 3+)
denotes the Fe 3+ ions in the tetrahedral A sites and [Fe 3+2/3 01/3] denotes the Fe 3+ ions and thecation vacancies in the octahedral B sites of the spinel structure. Some of the 119Sb5+ ions adsorbed°on the surface of 'Y-Fe203 are considered to be trapped near to the vacancies because of valencecompensation. The hyperfine magnetic fields of the 119 Sb 5 + ions trapped to the vacancies are102

expected to be very small. The remaining low field components at high temperature are ascribedto these trapped ions.
The detailed investigation is in progress.

Y- Fe 2 0 a
As adsorbed

10

5

200°C

5
~

0
(fJ

c

Q

::;
-9

300°C

+-'
(fJ

(:5

400°C

5
o ~--~----~--~~o- 14
Velocit y(mm / secl

Fig. 1.
Emission Mossbauer
spectra of ')'-Fe 20 3 and Cr 20 3 atliquid nitrogen temperature.

+14

:~
o

50
100
Hyperfine field

150( kOe)

Fig. 2.
The distribution of thehyperfine magnetic fields for the" as adsorbed" and heat-treatedspecimen of ')'-Fe 20 3 .

ReferencesI)

T. Okada, H. Sekizawa, F. Arnbe , and S. Arnbe: RIKEN Accel. Progr. Rep. , li, 91 (1981).

2)

T. Okada , S. Arnbe, F. Arnbe , and H. Sekizawa : 1. Phys. Chern. , 86, 4726 (198 2).

3)
4)

T. Okada, S. Ambe, F. Arnbe, and H. Sekizawa: p. 98 in this report.
1. Hesse and A. Riibartsch: 1. Phys. E. Sci. Instrurn.,--.l, 526 (1974).

103

III -2-17.

Perturbed Angular Correlation of r-Rays Emitted froml11Cd(+- 111In) on a-Fe203' Cr203, and a-A 1 2,0 3

Surfaces

K. Asai, F. Ambe, S. Ambe, and H. Sekizawa

The present work aims to utilize perturbed angular correlation measurements in studying thechemical states of dilute metal ions adsorbed onto the surfaces of oxides. In this report, we
present the results obtained on time differential perturbed angular correlation (TDPAC) of ,),-rays
emitted from 111Cd(+- 1HIn) on corundum-type antiferromagnets a-Fe 20 3, Cr 20 3 and a diamagnet
a-AI 20 3•

Samples were hydrolytically prepared. About 100 mg of a-Fe 20 3, Cr 20 3, or ~-AI203
powder was added to a dilute HCI solution (pH 2 "-' 3) of "carrier-free" lllIn. Then, the pH of
the solution was adjusted to 7 - 8 with a dilute NaOH solution, and the suspension was stirred
to let the 111In ions be adsorbed onto the oxide surfaces. The oxide was separated by centrifugation and washed with distilled water several times to remove C I - ions, and then dried overP205 in vacuum at room temperature. A portion of the oxide containing about 60 J,LCi of ll1In
was subjected to TDPAC measurement.
The time spectra of 173 - 247 keY 'Y-'Y cascade emitted from l11Cd were taken with aconventional fast-slow coincidence set up with two NaI(TI) detectors at room temperature andalso at 77 K. For a polycrystalline specimen, the TDPAC spectrum is expressed in the form

wee ,t) = k =even~ Akk(t)P k (cos e),
where e is the angle between the cascade ')'-rays, t the interval between them, and Pk the Legendre
polynomials.1) Therefore, the perturbation factor A21t) is derived from W(180°, t) and W(90°, t)
in the formby neglecting the higher terms Akk(t) with k > 4.
Figure I shows the perturbation factor A 21t) for ~-A1203 at room temperature. As can beseen, the factor decreases to become almost zero in a comparatively short time ("-' IOns), thenrecovers a little, and thereafter exhibits no visible structure but keeps nonzero value in average.
This apparently non-periodic behavior, which is common to all A 21t) observed in this work,suggests that intensities of the hyperfine interactions have a wide distribution, and/or that they
are time-dependent. Figure 2 shows the smoothed data of A2lt) in the vicinity of t = O. It isfound for all the specimens that A 22(t) decreases and recovers in a shorter time at 77 K than atroom temperature. This finding means that the hyperfine interactions at 77 K are stronger inaverage, and/or have a longer correlation time than those at room temperature.
It is considered that the dominant hyperfine interactions are associated with the unstable
excited ionic states created by the preceding electron capture decay ct llIn ~ 111 Cd). After the

- - - - - - --

-

104

aDa
0.0.6
oat room tem perature
A at 77 K

0..04

0..0.2111~-a.08t-

0.04
Cd on cr-Al 20 3 a1 room 1emperature

<{
L

o
.
t; - aOEr:-:2c.~ -o.a4f--.

ro

'

.0
L

:J

~ -0.02-

'.

Q

a

I

I

50.

lao.

1

150.

Ti me (ns)Fig. 1.

Perturbation factor A2it) of the 11lCd'Y-'Y correlation on ~-AI203 at room temperature.

aFig. 2.

10
15
T ime (ns)20.

Perturbation factors A 2i t )of 111Cd 'Y-'Y correlations at room
temperature and at 77 K: (a) on
a-Fe 20 3 , (b) on Cr 20 3 , and (c) on

a-A 1203.
Auger process following the electron capture, the ion is left in one of the various unstable charge
states, and relaxes to the stable state in a certain time duration. 2) On the unstable ions, intensitiesof the hyperfine interactions have a wide distribution and also change with time. 2) The more
rapid attenuation at 77 K means that the electronic relaxation becomes slow at low temperature.
The relaxation process reflects the character of the chemical bonds between the adsorbed
ions and the substrate oxides. Though precise analysis is now in progress, it can be said that
the TDPAC measurement is a useful tool for these studies.

References
1)

H. Frauenfelder and R. M. Steffen:"~-, {3-, and 'Y-Ray Spectroscopy",

K. Siegbahn), North-Holland, Amsterdam (1964).
2)

H. Haas and D. A. Shirley: J. Chern. Phys., 58, 3339 (1973).

l, (ed. by

105

111-2- 18.

Dependence of Secondary Electron Emission
Coefficients on Metal Targets under
Bombardment with Bare Projectiles

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

There is still a shortage of measurements of the secondary electron emission coefficients 'Y
under heavy ion bombardment in the high-energy region of several MeV /amu.
According to Oda and Lyman,1) the energy dependence of 'Y is different from that of S, theenergy loss per unit path length of projectiles, and the' dependence of 'Y on the projectile atomic
number z1 is the same with that of S. On the contrary, according to Clerc et al.,2) the energy
dependence of 'Y agrees with that of S, and the z 1-dependence of 'Y does not. In the previous
paper 3) we revealed that the energy dependence of'Y was different from that of S. This result
agreed with those by Oda and Lyman.
In the present paper we examine the z1 -dependence of 'Y. Figure 1 shows both 'Ybad< (thebackward secondary electron emission coefficients) for thick Al and Ag targets and for an Au
foil target, and 'Yfor (the forward secondary electron emission coefficients) for the Au foil target.
Incident ions were He 2+ , C6+, N 7+, and 0 8+, and their energy was 6.2 MeV /amu. The experimental
apparatus and conditions are given in detail elsewhere. 4 ) This figure shows the clear deviationfrom proportionality to z1 2 for 'Ybad< and zi 2 for 'Yfor' where zi is the effective charge number ofprojectiles. The deviation can be given by

..
~

0.7 ·

o

Au foil target

Ag thick target.7

o Al thick target

A..
0.6

.6

-- -4- 0.5

N

~-

--

.5

--:A,.

0 .4

.4
* ~

-'"'

------~-D?-N"b.--_o~0.3.2.3 -----?--

0.2

0.2

0.1

0.1

~--~--~----~--~·----~--~--~o10Fig. l.

20

30

40

50

60

70

Dependence of 'Yback /z12 on zl for A 1 and Ag thicktargets, and those of 'Yback /z12 and 'Y for/Zi 2 for an Au foil target.
Incident energy is 6.2 MeV / amu.

106

'Ybad\./ ZI2 ex 1 -'Yfor/Z~2

ex

O.006z I 2, for all three targets,

1 - O.004z I 2, for the Au foil target.

(1)

The decreasing trend with increasing atomic number is consistent with the experimental
results by Clerc et aI., 2) and is not with those by Oda and Lyman. l )According to the theory by Schou,5) 'Y can be written as,'Y = {3(2). S . A,

where {3 is the dimensionless factor and (3'S gives the energy dissipated per unit path length toelectrons in the surface region of a target, and A is the factor which gives the fraction of
secondary electrons (SE's) that can escape from the surface and is dependent on the surface
barrier height U. Then with respect to the foil target, it can be written that(3)
'Y for= {3 d . Sd . Ad'

where subscripts 0 and d mean the positions of the inlet and outlet surfaces, respectively.
Under the reasonable assumptions that for the film target which is thin enough, thesummation of the energies dissipated to target electrons in the inlet and outlet surface regions
is equal to S, that is, {3o + {3d = 1, and that the factor A is the same both on the inlet and outlet
surfaces, that is, Ao = Ad' values of {3o' {3d' and Ao (= Ad) can be obtained from experimental
values of 'Ybad\. and 'Yfor' Figure 2 shows the zl-dependence of {3o' {3d' and Ao (= Ad) for the Au
foil target. The factors {3o and {3d do not depend on zl ' but the factor A does depend on it. It
suggests that the surface barrier height U changes dynamically with S.

1.0

1.0
0.8

0.8

8d
O.

-----N

O.

D

-0
~

0-

0.6
u
~

80
fi---~-

0.4

0

<5

~

<
0.2

o . 1 0L...- - ' 1 0-----'-:20- -3..L...- 4 L0 --'-50-----'-:
60- -7......
0 0

Fig. 2.

8.......
0 0.1

Dependences of {3o' (3d' and Ao(= Ad) on zl' Both (3()
and (3d are independent of zi within data scattering of ± 5 %,but Ao(= Ad) depends on zi .

107

References

2)

N. Oda and J. T. Lyman: Radiat. Res.,L Suppl., p. 20 (1965).
H. G. Clerc, H. J. Gehrhardt, L. Richter, and K. H. Schmidt: Nucl. Instr. and Meth.,
ill, 325 (1973).

3)

A. Koyama, T. Shikata, H. Sakairi, and E. Yagi: RIKEN Accel. Progr. Rep., 12,88 (1981).

4)
5)

A. Koyama, T. Shikata, H. Sakairi, and E. Yagi: Jpn. J. Appl. Phys., lL 1216 (1982).
J. Schou: Phys. Rev. B, 22, 2141 (1980).

1)

108

III-2-19.

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

E. Yagi, A. Koyama, H. Sakairi, and
R. R. Hasiguti*

The investigation on the lattice location of implanted impurity atoms provides theinformation on the interaction of impurities with defects, both of which are introduced by theion implantation. From the point of view of technology, it is also important for the understandingof the mechanism of material modification made by the ion implantation method. It has been
considered that there is a difference in the impurity-defect interaction between oversized
impurities and undersized ones. In the present study, the lattice location of oversized impurity
Sn atoms implanted into Al crystals is investigated by means of channeling method.
The implantation was carried out at room temperature and at 150 kV with the dose of
The axial channeling effect was investigated with respect to < 100 >, <110 >, and< III > axes by means of backscattering with 1 MeV He+ ions. Figure 1 shows the normalizedbackscattering yields from A 1 and Sn atoms as a function of the angle between the incident
beam direction and the concerned crystallographic axis. The backscattering yields from Sn atoms
give a shallower dip than the AI-dip in each of three cases. In the < III > angular scan, a very
narrow dip was observed for Sn yields. The location of Sn atoms was determined from theanalysis of the results of angular scan by using the multistring potential. About 35% of Sn
atoms occupy the substitutional lattice sites and 20% occupy the interstitial sites which aredisplaced from the lattice points in the < 100 > direction by about 0.72 A. The remaining 45%
of Sn atoms are at random sites.
10 14 Sn/cm 2 .

10' " Sn/cm 2oAI<I I! )

<100>

I

j

~\i

.++

\

Q)

'"u

(J)

\

Q)

\

c:: 0.5

i

o -2

-1

.'

\
l

\)

z

,h

~

it

'~~f

\

D

'r .... .t.tt

\

t+

+

r

~ [
~l

'!.

o

1- 2
Angle

- j

( Degrees )Fig. 1.
The < 100 >, < 110 >, and < III > angular scansof the backscattering yields of He+ ions in Sn-implanted Al
crystals.
* The Science University of Tokyo.

2

109

111-2-20.

Amorphization of Diamond Surface layer
by Zn-implantation

S. Sato, M. Iwaki, and H. Sakairi

In our previous report, radiation damage and depth profile of Ar-implanted diamond havebeen investigated by means of 1 MeV 4He channeling technique with the use of the TANDETRON.l)
The results show that the average projected"range and standard deviation of Ar implanted indiamond are in good agreement with these predicted by the range theory and Ar-implantation
results in producing an amorphous layer with high conductivity. In the present report, a study
has been made of radiation damage and depth profile of Zn-implanted diamond by means ofchanneling technique.
Substrates used were natural and colorless diamonds with the surface nearly parallel to the(111) plane. Ion implantation was performed with the dose of 1 X 10 16 Zn/ cm 2 at the energy of
150 keV. The ion beam was sent in a direction deviating by a few degrees from the < III >crystal axis in order to reduce the deep penetration of implanted zinc by channeling.
Channeling measurements (Rutherford backscattering) were done by using 1 MeV 4He+ withthe fluence of 5 J-LC. Backscattered particles at an angle of 150 0 were detected and analyzed bya solid state detecter and conventional electronics.
Figures 1 and 2 show the < III > aligned and random specta observed for zinc implanted
diamond. The leading edge of the diamond target is at channel number 438 (located at halfheight) and the energy edge of zinc at the diamond surface at channel number 1274. Theenergies at channel numbers 438 and 1274 are 0.273 and 0.795 MeV, respectively. The spectra
obtained for backscattered particles from zinc implanted in diamond do not exhibit any difference
between random and channeling spectra as shown in Fig. 1. Moreover, as shown in Fig. 2, the...

• Ra ndom

200

</)

c

::>

o

U

100

..
o
.· ~e

~"""~oo~o~o°Oo ~ooo

1000

~--~
1l0
~
0------~----~~~

Cha nnel number

Fig. 1.
Random (e) and < III > aligned (0 ) spectra ofzinc implanted in diamond.

110

.0

o·

1000

• Randomo <111>
0

0

00

0

o ••

• ••••• e.
000

'"C

a

000

o

::J

o

1 QCJOo ~~
~

0

0

o

U

0

0

0

0

••

•••
0 o~

0
0

0

000000 00

0

0 00

•

t;, ••• ~ 0 eg ~ Q . 0
0

500
r

Amo rphous

0

Sur face0•----'---'------'-''--'--------'L......I

o
· 0

200

300

400

500

Ch ann el number

Fig. 2
Random (e) and < 111 > aligned (0) spectraof diamond implanted with zinc.
channeling spectrum overlaps with the random spectrum at channel number above 304. These
results display that zinc implantation in diamond produces the amorphous layer near its surface,where implanted zinc atoms are located at random sites.
The depth profile of implanted zinc and the thickness of the amorphous layer can beobtained from Figs. 1 and 2 by using a zero-order analysis. The solid line Fig. 1 indicates thedepth distribution predicted by the range theory. The depth corresponding to the peak obtained
from the spectra is about 50.6 nm, which is in good agreement with the predicted range of 50.7
nm. The standard deviation calculated from the FWHM of the spectra is about 22.3 nm, which
is a little larger than the predicted value of 15.4 nm.
The thickness of the amorphous layer is, if it is assumed to be the region from channel 286
to 433 as indicated in the figure, about 97.9 nm, which is 1.9 times as large as the average
projected range. The amorphous layer of the diamond surface produced by Zn-implantation
exhibited electrical conductivity, which was measured by means of a four point probe method.
The sheet resistivity of the specimen was about 130 n/cm 2• If the conductivity is assumed to be
attributed to amorphous layer, the resistivity is 130 X 97.9 X 10-9= 1.3 X 13 - 3 n·cm, which isone half as large as that of Ar-implanted diamond or the glassy carbon (produced by Tokai
Carbon Company Ltd.). The results show that the conductivity enhancement for zinc
implantation may be due not only to the amorphous phase but also to implanted metallic
elements themselves.
It is concluded that the average predicted range of zinc implanted in diamond is in fairly
good agreement with that predicted by the range theory. By zinc implantation of 1 X 16 16
ions/cm 2 at 150 keV , the conductivity induced by zinc implantation is larger than that of theglassy carbon on the market.

Reference
1)

M. Iwaki and H. Sakairi: RIKEN Accel. Progr. Rep., 12,98 (1981).

111

III -2-21.

Pulsed laser Annealing of Cd-implanted Ga P

K. Aono, M. Iwaki, and S. Namba

Laser annealing of disordered semiconductors is a relatively new field of semiconductor
physics. The laser beam used for annealing has an energy large enough for rapid recrystallizationin heavily damaged regions near water surface , such as ion-implanted layers which range fromthe surface to a few hundred nanometers. In the present work, the effect of laser irradiation on
the profiles of Cd and radiation damage in Cd-implanted GaP was investigated by means of a 4He+
channeling technique.
Substrates used were n-GaP with the surface parallel to the (Ill) plane. Surfaces of all
wafers were mirror-polished and chemically etched . Cadmium-implantations were carried out at
ion energies of 50, 100, and 150 keY with doses from 1 X 10 12 to 1 X 10 16 ions cm- 2 at 2 X 10- 6
Torr. Target temperature during implantation was held at room temperature or at about 350°C.
The Cd ion beam was sent in a direction deviating by a few degrees from the < 111 > crystal
axis. Annealing was carried out with nanosecond pulsed lasers. The surface was swept by thelaser spot, 100 JIm in diameter, to heat the implanted area. The samples mounted on a 3 axis
goniometer in a target chamber, which was kept at a pressure below'" 5 X 10- 6 Torr, were
en

30

~

0

Q)

( b) Jaser annealed specimen
10 15 Cd + em - 2
150keVc

10 Cd + em - 2
150keV
15

u
"D

~ 30

(a) as-implanted specimen

c

~

8
~

20

20

Q)

>.
tl.()

c

~ 10
..Y
U
<1:J

CD

...

00

0

. ..

~ 10

0

0
. 0 •

<1:J

u
en

tl.()

c

o.
00

o . 00 • ••0•000 ••• 0

1. 25

0°

en

a.

..Y

..-

1. 30

Energyo •• 0
o 0
o •

<1:J
U

• 0
•••0
0
0
0
oc&

g

0

. 0
00· · ·

.

0.
0

0
00

.0

O~. • ......
' _0 _._ _ _ _-:-':'~CLu........·~c2~.S?cEoo~o-

CD

1. 25
Energy( MeV)

1. 30( MeV)(e) hot implanted specimen~ 30
c10 15 Cd + em
150keV

~

o

u

~

:<

20

Q)

>.
tl.()

c

o 0

2 10

00

000

<1:J

00

o

U

en

00

..Y

u

<1:J

CD

Fig. 1.

o

o

0

000
0
0

0
•

00
0

o

o ••
• •
• •0 o .
oe.!!2 •• _.!.!•.• ~.-L..!.....-.~'W •••• - 1. 25
1. 30
Energy ( MeV)

Random (0 ) and < III > aligned (e) spectra of Cd implanted in GaP.

112

analyzed with 1.5 MeV 4He+ beam using the Rutherford backscattering and channeling technique.
Backscattered particles at an angle of 150 were detected and analyzed by a conventional
electronics.
0

Ga surface

j 10" Cd' cm-'

~ 300
c

150ke V

::::J

o

U

~

<D

200

>00

c

~ 100
(\J

u
<J1
~

U
(\J

CD

( c)

0E===~==~~~~~
1.15
1. 20
En ergy( MeV )

Fig. 2.
Random (- - - - -) and < 111 > aligned (---) spectra of GaP
implanted with Cd.
(a)
(b)
(c)
(d)

the as-implanted specimen,
the laser annealed specimen ,the hot implanted specimen,
the un-implanted specimen.

Figures 1 and 2 shows the random and < 111 > aligned spectra observed for Cd-implanted
GaP with 15 15 ions cm- 2 at 150 keV. The Cd depth profiles in the random spectra of
as-implanted, laser annealed and hot implanted specimens have similar distributions which are
gaussian as shown in Fig. 1. No difference is exhibited between the random and the aligned
spectra of the as-implanted specimen and the laser annealed specimens. However, in the scattering
yield from the hot implanted specimen, the aligned spectrum shows a strong reduction. This
result shows that most of Cd atoms occupy substitutional lattice sites in the case of hot
implantation.
Radiation damages in Cd-implanted layers were investigated from the spectra obtained fromGa in GaP. The result is shown in Fig. 2. Backscattering yields of the aligned spectra decrease
after laser irradiation, and for hot implantation they are almost the same as those of an
un-implanted specimen.
From channeling measurements we can conclude that radiation damage in the hot implanted
specimen was smaller than that of the laser annealed specimen.

113

III-2-22.

Radiation Damages in Amorphous Alloys
44

Irradiated with C + and N + Ions

S. Nanao,* Y. Watanabe,* K. Oda,* and N. Shiotani

Recent studies suggest that amorphous alloys have large resistance against radiation damages.
This originates mainly in the characteristics of amorphous alloys, that is, random atomic arrangement. At the present stage, however, very few information has been obtained on the structuresand recovery behaviors of the radiation damages produced in amorphous alloys.
The aim of the present study is to investigate the recovery stages of the radiation damages
induced in an amorphous alloy Fe 80B2o by irradiation with C4 + and N4 + ions at low temperaturesusing the cyclotron and to identify the defects and/or relaxation of the amorphous structure
relevant to each recovery-stage.
As the first step, we have measured the changes in electrical resistivity due to isochronalannealing of 30 min. after irradiation with 80 MeV C4+ ions at 77 K. The irradiation was
performed with mean current of 90 nA in a vacuum. The total dose was about 10 21 ions/m 2 .
The resistivity measurements were done at 77 K.
The results are shown in Fig. 1. Two or three stages are observed in the change of electricalresistivity as a function of the annealing temperature. Above 0 °c, no appreciable difference inthe electrical resistivity are observed up to 160°C, which indicates that nearly all the damages
have recovered below 0 °c.
Further measurements and analyses are now in progress.

1. 02

Q
---..... 1. 00
Q.

.. .... -.

.-. -.

1:' 0.98
>
ifJ
ifJ

~

..

0.96
0. 94

Q)

> 0.92~Q). ...-.....

0.90

0:::

0.88

~ 200 - 150 - 100

- 50

o

50

Annea li ng tempe ratur e ( 'C )Fig. l.
Relative resistivity (p/po) measured
at 77 K as a function of isochronal annealing
temperature in a C4 + irradiated Fe 80 B2oamorphous alloy.
* Institute of Industrial Science, University of Tokyo.

114

1II-2-23.

Positron Angular Correlation Measurements on Oxygen
Implanted Molybdenum Containing Voids

M. Hasegawa,* E. Kuramoto,** and N. Shiotani

Recently it has been discovered that positroniums are formed in niobium and vanadium
metals which contain voids and small amount of impurity atoms such as oxygen and carbon
atoms. The positrons are considered to be trapped at the inner surface of the voids. However,by the presence of the oxygen and carbon atoms the trapping potential for the positrons at thesurface is changed so as to convert the trapped positrons into positroniums which can movein the voids. In the present study an attempt is made to see the positronium formation inmolybdenum.
The specimen containing almost no oxygen nor carbon impurities was first irradiated byneutrons in order to produce the voids. At this stage the positronium formation was not detected.
Then the oxygen beam 0 5+ was accelerated to 90 MeV by the cyclotron and implanted into thespecimen up to 6.24 X 10 14 05+jcm 2 at room temperature. According to the calculation bymodified E-DEP-l code the implanted oxygen distribution should spread from the surface toabout 40 11m in depth and has a sharp peak at about 30 11m. However, the actual distribution
spreads more due to beam heating and migration of lattice defects produced during implantation.
Positron angular correlation measurements were made on this specimen. The results are shownin Figs. I and 2. The oxygen implantation made the half width of the angular correlation curve
narrower than that of as-neutron-irradiated one. However, the width is still much broader thanthose observed in niobium and vanadium, the half width of which is about 2 mrad. Therefore,
the positronium formation in the voids in molybdenum could not be concluded, but sometendency for it is thought to be taking place. Probably the amount of oxygen implanted was
not large enough to modify the surface of all the voids in the specimen.
Pure Moo Unirr.

150

Mo

150

Neu tron irr.

" J 1X1021n /c m~Ul·c( 1.2 X I02In / cm~ -640'C)-4.00·C::J

OH irr .
( 94MeV, 6.24x 10"05+ I cm 2 )

>-

'"

100

100

50

50

:.0

~

Ul
C
:::l

0

u

0

-5

Fig. 1.

0

5

15

o -5

e (mrad)Positron angular correlation

curve for unirradiated and neutronirradiated molybdenum.

o15
Angle i n mrad .

Fig. 2.
Positron angular correlation
curve for neutron-irradiated and oxygen
implanted molybdenum.

* The Research Institute for Iron, Steel and Other Metals, Tohoku University.
** Research Institute for Applied Mechanics, Kyushu University.

115

III-2-24.

Effect of an Iniected Helium Layer near Surface on theTensile Properties of Fe-N i-Cr

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

It is well known that helium generated by (n,ex) reactions causes a loss of ductility in alloys
used for fast breeder and magnetic fusion reactor structural components, because it accumulates
at grain boundaries where it has a strong positive influence on intergranular fracture. Among theexperimental methods to study this phenomenon, helium injection by using an accelerator is aconvenient way of introducing large amount of helium into the specimen in a short time.
Therefore, we took this method, and have investigated effect of helium on the high temperaturetensile properties of various Fe- Ni-Cr alloys, using sheet specimens into which helium was
uniformly injected all over their thickness by ex particle irradiation of the cyclotron.1)
On account of experimental restriction, however, the helium concentration in this "uniform
helium injection mode" is low (only up to 10 at.ppm) compared to that produced in fast breeder
or fusion reactor environment. On the other hand, "local helium injection mode" in which helium
is locally injected into a thin layer near the surface of the specimen can form a portion of muchhigher helium concentration (up to 100 at.ppm) at the same ex particle irradiation dose. And it
seems likely that some indication of premature intergranular fracture of the helium injected layer
during the high temperature tensile test after local helium injection would be observed on the
stress-strain curve and thereby some of the imformation could be obtained on the effect of highly
concentrated helium on the high temperature tensile properties of the alloy. In the present work,
therefore, helium was injected with local helium injection mode, and effect of highly concentrated
helium on the high temperature tensile properties was studied for several Fe- Ni-Cr alloys.
Result of chemical analysis of the alloys used are presented in Table 1. SUS 316 is a typicalfast breeder structural material. Alloys 7817 and 7818 are 'Y'-Ni/Ti, AI) and 'Y"-Ni3 Nb precipitation strengthened alloys, respectively. Tensile test specimens were die-stamped out from 0.2 mm
thick sheets. The dimension of gauge section was 10 mm long, 4 mm wide, and 0.2 mm thick.
The specimens were solution treated for 30 min. at certain temperature : 1050 °c for SUS 316,
1000 °c for 7817, and 1100 °c for 7818. This treatment resulted in the mean grain sizes ofTable 1. Chemical composition of the samples. (wt%)
Alloy

C

SUS 316 0.043

Ni

Cr

Mo

13.9

16.1

2.50

Ti

7817

0.021

40.2

14.6

3.19

2.01

7818

0.024

39.2

14.7

3.03

0.31

* National Research lnstitu te of Metals.

Al

Nb

0.87
2.96

Fe

Si

Mn

0.44

1.42

0.0006 balance

0.47

0.19

0.0049 balance

0.48

0.19

0.0048 balance

B

116

46 11m, 20 11m, and 69 11m, respectively. Finally, the specimens received various pre-injection

thermomechanical treatments . . Helium was injected at constant high temperature (650°C), by
using the cyclotron. The helium concentration and thickness of the helium injected layer wereabout 5 - 100 at. ppm and 10 - 20 ,urn. The tensile tests were carried out at 650°C or 750 °c
in vacuum below 5 X 10- 6 Torr. The fracture surface of the specimens was examined by ascanning electron microscope.

Electron fractographs of the fracture surface of tensile tested SUS 316
Fig. 1.
which contained a helium injected layer (100 at. ppm He, 10 11m thick).
Pre-injection treatment: ST (1050 °c, 30 min.), test temperature: 650°C, strain
rate: 5 X 10- 4 s- l. Figure (b) is a magnified picture of the rectangular area shownin figure (a).

80

(a )

60

7817 alloy
ST+CW (98% )400

F = 650 C

Fig. 2.
Stress-strain curves for locallyhelium injected 7817 alloy.
Test temperature: 650°C, strain rate:
5XIO- 4 s- 1 . Figure (a) pre-injection

(/)
(/)

;::
U)

80

(bJ

7817 alloy0

ST + A ( 700 C, 300h )0"/'= 650 C
0

2

4

6

8 10 12 14 16 18
Str ai n (%)

treatment: ST (1000 °c, 30 min) + CW
(9.8 %), helium injected layer: 100 at.ppm
He, 10 11m thick. Figure (b) pre-injection
treatment: ST (1000 °c, 30 min) + A(700°C, 300 h), helium injected layer:
50 at.ppm He, 20 11m thick.

117

As shown in Fig. I, fractographs by SEM revealed that in almost all cases, fracture occurred,at least partially, in intergranular brittle mode in the helium injected layer and its adjacentregion, while the other portion of the specimen showed a transgranular ductile fashion. Thisobservation implies that intergranular fracture mentioned above should be caused by injected
helium. On the other hand, as illustrated in Fig. 2, the load drop which should result frompremature fracture of the helium injected layer was observed on some of the high temperaturestress-strain curves of locally helium injected specimens (Fig. 2a), while there were some others on
which any indication of premature fracture was hardly observed (Fig. 2b). Thus, the results ofthe tensile tests are still difficult to explain at the present time, and more systematic experimentschanging the helium concentration, thickness of the helium injected layer, the strength of thealloys, and so on, will be needed to obtain imformation on the effect of highly concentrated
helium on high temperature tensile properties of alloys.

118

III -2-25.

Effects of Fast Neutron Irradiation on
Insulating Materials

H. Kamitsubo, I. Kohno, S. Motonaga, M. Yanokura,
T. Shikata, M. Yatsuhashi,* T. Suematsu,* and H. Kobayashi*

Needs for use of plastics and elastmers in areas of high-radiation levels are increasing anddetailed information on radiation-induced effects in polymers is required to determine theirstability in their applications and the service life that can be expected.
The radiation effects in the plastics and elastmers have been investigated mainly by irradiatingwith gamma rays from 60Co sources or electron linacs and also slow neutrons from reactors.
However it becomes more important to get the information on the effects of fast neutron
irradiations in these materials, because development of fast breeder reactors and thermonuclear
fusion reactors, which will generate much higher nux of fast neutrons than the existing reactors,
is hurried on.
We have studied the effects induced by fast neutrons in polymers which are used as insulating
material for electric wires. Change of resistivity, dielectric constant, dielectric loss, tensile
strength and elongation under the influence of its fast neutron irradiation is to be measured forthese materials. Size of the samples was determined to be 5 cm by 5 cm in area and I mm inthickness from the minimum size needed for the measurement of mechanical properties. Taking
into account the results of gamma ray irradiation,1) the maximum dose should be as high as
5 X 10 8 rad. and total neutron fluence must be higher than 10 16 neutrons/ cm 2 . Figure 1 shows
the irradiation system. Fast neutrons were generated by bombarding a thick beryllium target
with 20 MeV deuterons from the cyclotron. Two beryllium plates of 2 mm in thickness weretightly fixed to a water-cooled flange, which is insulated from the earth and beam current on
the target could be measured by the current integrator.
Neutrons from the thick target have broad energy spectra and their intensity distribution
depends strongly on the emission angles. 2) Neutron fluence as well as total dose was estimatedusing data in Ref. 2 and conversion rate of 1 rad = 2 X 10 8 neutrons. We tried to determine
the neutron fluence by the activation method as described below. In order to get as high neutron
flux as possible at the samples, the samples were placed very close to the target. As shown in
Fig. I, a sample holder which can contain three samples at the same time was attached directly
slit~deut~ron bellc=::::>

Iaee

....
Scm

* Fujikura Cable Works Ltd .

to current
integrator

Fig. 1.

The irradiation system.

119

to the outer side of the target flange. The distance between the target and the samples was
small so that the neutron fluence was not uniform on the samples. Foils of aluminum, iron andnickel of the same size as the sample were put together with samples and irradiated at the sametime. After the irradiation, each foil was cut into 25 pieces of I em X I em and the induced
radio-activities were measured for them. Thresholds of neutron activation are different for threekinds of foils so that we can get the fluence of neutrons whose energy is higher than 2 MeV.
The irradiation was done with the average deuteron current of 10 /lA. Five samples ofpolyviny1chloride were irradiated for I, 5, 7, 11, and 12 h, respectively. Figure 2 shows the fluence
distribution at the sample which was irradiated for 12 h. Mechanical and electric measurements
are in progress and the irradiation at higher fluence is scheduled.

1 X 10 14
/'

/

--

......

"I
I
I\

5x 10 14l x l0 15\' ......

-----

Measured total neutron flux
Fig. 2.
distribution at the target position using

5cm

the activation method.

References
1)

2)

M. Asaka, S. Yamamoto, M. Yatsuhashi, G. Hara, and S. Sakai: Fujikura Densen Giho, 48,
61 (1973).
M.A. Lone, C. B. Bigham, J. S. Fraser, H. R. Schneider, T. K. Alexander, A. J. Ferguson,and A. B. Mcdonald: Nucl. Instr. and Methods, 143,331 (1977).

120

III -3.

Radiochemistry and Nuclear Chemistry1.

Radioisotope Production and Labelled
Compound Synthesis

Y. Minai, T. Nozaki, S.Ambe, and M. Iwamoto
In this period, the production of 29Al and the synthesis of radiobrpmine-Iabelled
6-bromopurine and 6-bromo-9-benzylpurine have been studied.
Aluminium is abundant in nature, but its behaviour and role in the biosphere have remained
obscure. This is due to the absence of any radiotracer nuclide as well as of stable tracer nuclide.
We intended to produce 29 Al (6.7 min, ~ - , 1.27 MeV 'Y-ray) and to use it as a tracer in life
sciences, in spite of its limited life. The 26Mg(a, p)29Al reaction is regarded as the only usefulreaction for the production of 29 A I in high specific activity. The excitation function and thicktarget yield for this reaction were measured together with those for some relevant reactions. The
results for the main reaction are shown in Fig. 1.

~----------------------~3

Fig. 1.
Excitation function (A) and thicktarget yield (B) for the 26Mg(a, p )29Alc
Q

reaction.

u
<l.l
(f)
(f)
(f)

Target: Magnesium metal of natural isotopicocomposition. Star plots: Experimentaloresult of the thick target yield; Full line
for the thick target yield: Result obtained
In cident energy( MeV)

by calculation from the excitation function.

Two methods were examined for the chemical separation of the no-carrier-added 29A I fromthe magnesium target: (1) adsorption of the 29 A 1 in a cellulose powder column from its neutral
solution, followed by elution with a dilute acid, and (2) extraction of the 29 A I as acetylacetonate
into benzene from a faintly acid solution, followed by evaporation of the organic solvent andsublimation of the 29 Al acetylacetonate. In Method I, the procedure can be completed within 20
min with an 29Al yield of about 60 %. The separated 29 AI, however, is inevitably contaminatedwith a small fraction of by-product radioactivities, such as 27Mg, 18F, and 24Na, and of target
magnesium. In Method 2, the 29 Al can be separated in excellent radiochemical and chemical.
purity. The separation, however, requires 20 to 30 min with a yield of about 30 %. Method I
is preferred in the preparation of 29 A I tracer for agricultural study, but Method 2 should be used
when the 29A I is injected to animals. About 1 mCi of 29 A I ready for injection is now prepared.
Efforts are being made for the shortening of the separation time and the elevation of the yield in
Method 2.

121

A preliminary study of 29 Al uptake by plants has been undertaken. Some plants were foundto take up 29Al fairly rapidly from an aqueous solution.
In 1975, we prepared 18F -labelled 2- and 6-fluoro-9-benzylpurine and measured theiranimal distribution. 1) The 18F activity injected as 6-fluoro-9-benzylpurine showed a notableconcentration in the brain as well as in the skeleton. Since then physiological behaviour of thiscompound has been investigated, and its suitable preparation method was found in the National
Institute of Radiological Sciences. 2) Now in collaboration with this institute, we intend to prepare
77Br- and 75Br-Iabelled 6-bromo-9-benzylpurine and to study its in vivo behaviour, expectingsome possibility for the radiobromine to show a high brain concentration without any notable
accumulation in the skeleton.
This compound and 6-bromopurine were found to be labelled successfully by isotopic
exchange in dehydrated dimethylformamide at 130°C. The radiobromine was produced by the
75 As(a, 2n) 77Br or 75 AseHe, 3n) 75Br reaction in a gallium arsenide target, and was separated bysublimation under radio-frequency fusion of the target. Several materials were tested as the fluxin the target fusion, and copper grains were found to give the best sublimation efficiency. In
the fusion for a few minutes the radiobromine came out from the melt almost quantitatively,
and, after being carried for a short distance by a slow helium stream, deposited on the inside wall.
of the sublimation apparatus with a small amount of metallic arsenic. The radiobromine was thenwashed out in dehydrated dimethylformamide. About half of the radiobromine remained on thewall, though nearly quantitative washing out by water was possible.
The isotopic exchange was effected at 130°C in 1 me of the solvent containing the radiobromine and a few milligrammes of the substrate compound. The labelled organic compound wasseparated from the inorganic bromine by a small silica gel column with the eluent of AcOEt EtOH (9 vol : 1 vol). About 80 % of the radiobromine was found to be incorporated into thebromo purines in 2 h. Their animal distribution will be studied very soon.

References
1)

T. Nozaki, S. Ambe, M. Iwamoto, T. Ohsawa, T. Karasawa, M. Okano, Y. Kasida, T. Ido,
K. Suzuki, K. Fukushi, L. Iwata, T. Irie, T. Hara, and K. Taki: IPCR Cyclotron Progr. Rep.,

2., 10 1 (1975) .
2)

T. Irie, K. Fukushi, O. Inoue, T. Yamasaki, T. Ido, and T. Nozaki: Int. J. appl. Radiat.
Isotopes, 33, 633 (1982).

122

III-3-2.

Charged Particle Activation Analysis of
Semiconductor Materials

T. Nozaki, Y. Itoh, and M. Iwamoto

Application of charged particle activation analysis to the study of semiconductor materials
has been continued in collaboration with various outside researchers. Main works in this periodare (1) determination of highly reliable calibration curve for the IR spectrophotometry of oxygenin semiconductor silicon, (2) analysis of nitrogen, oxygen and phosphorus in epitaxial films on
semicoductor silicon wafers, (3) more accurate determination of the solubility and diffusion
coefficient of oxygen in solid silicon at various temperatures, (4) more systematic study on surface
oxygen, and (5) some other studies concerning oxygen profiles and behaviour in silicon of various
histories. Two bombardment devices have been completed: one for successive bombardment of
4 samples in a vacuum, and the other for homogeneous bombardment of a sample along its length.
Oxygen in semiconductor silicon is routinely measured by IR spectrophotometry insemiconductor factories. Several different calibration curves have been reported for thisspectrophotometry and used. 1) It has thus been of ultimate importance, especially in commercial
transaction of semiconductor silicon, to establish highly reliable calibration curve for thismeasurement together with corresponding practical procedure and to use them commonly all over
the world. It is still better to prepare a sufficient number of silicon wafers of exactly known
oxygen concentrations and distribute a set of the wafers with various oxygen contents to anyone
who want to use it as the standard in this measurement.
In Japan a committee was set up for these purposes. Under its supervision, silicon wafers
with various oxygen contents and thicknesses were carefully prepared at several places andsubmitted to the IR spectrophotometry in companies and research institutes. About 70 wafers
in all were measured in about 15 laboratories. After the IR measurement, 22 wafers, all I mm
thick, were analyzed by charged particle activation analysis with the 160eHe, p) 18 F reaction in
our institute. Researchers from several companies and a research institute joined with us forthis oxygen analysis.
The wafer was bombarded with 3He particles (18 MeV, about 2 JiA) for 20 min behind analuminium foil (80 Jim thick), and then its surface layer (23 ± 2 Jim) was removed by etchingwith HF-HN0 3. The wafer was placed after I h from the end of bombardment, directly on aGe(Li) detector and the annihilation radiation was measured. The measurement was repeatedto give the decay curve, which indicated the absence of any other notable positron activity than
18F. As for the activation standard, a quartz plate was used with an aluminium cover of 20 Jim
thick, in which the incident 3He particle energy was degraded equally as in the silicon surface
layer removed by the etching. Within a period of each cyclotron machine time, usually 8 suchplates were bombarded for the ascertainment of reproducibility. The analysis of each siliconsample was repeated at least twice. Samples, for which the results of the first two analyses
deviate more than 4 % from each other, were subjected to third analysis. When the three
analyses gave no satisfactory results, fourth analysis was undertaken. Also, one common sample

123

was always analyzed in all machine times to indicate good reproducibility of the analysis.
The calibration curve thus obtained is shown in Fig. 1. This agrees well with the curve wereported previously, 1) ,2) and can be believed to be the most reliable of all the curves ever reported
for this purpose. Silicon wafers for use as the standard samples are now under preparation insome factories.
7 ~----~~----~~----~~----~~----~

I

E

u

<lJ

o

u

c

o
D-

o

U)

.D

«

25
Oxyge n co ncen t rat ion(10 17 at/cm 3 )Fig. 1.

Calibration curve for IR spectrophotometryof oxygen in silicon.
By being covered with a suitable epitaxial film, semiconductor silicon is known to beprovided with profitable characteristics in use as high-voltage rectifier. The film is composed ofnitrogen, oxygen, hydrogen, silicon, and sometimes phosphorus. In collaboration with HitachiLtd., nitrogen, oxygen, and phosphorus in the film made under various conditions were analyzed
by charged particle activation with the reactions 14N(p, a)llC, 160eHe, p) 18F, and 31p(a, 2n) 34m CI,
respectively. The sample was covered with a thin wafer of semiconductor silicon and bombarded
with the incident particles of such an energy as to be degraded approximately to the energy
corresponding to the maximum of the excitation function for the given reaction at the epitaxial
film. The induced activity was then measured nondestructively by a Ge(Li) detector, and the
decay was followed. Hydrogen was measured by Rutherford forward scattering; details about
this method is shown in a separate report of this volume. Some systematic dependence wasalready found between contents of these elements and preparation condition of the film. This
work is still in progress, and more detailed results will be reported in the next volume.
The measurement of oxygen solubility and diffusion coefficient in solid silicon has been
continued. The solubility curve is shown in Fig. 2 after slight modification of the previous
curve. 3) Both the solubility and diffusion coefficient curves show noticeable tailings in thelogarithm-liT expression, indicating the existence of some diffusion faster than the usual
diffusion into a perfect crystal. From thermochemical considerations, the faster diffusion can beassumed to be a rapid penetration of oxygen through a linage fault formed in the heat treatmentof the sample. Efforts are made by various techniques to verify this assumption.
The work of surface oxygen analysis also has been continued. 4) More varieties of samples
were analyzed under various atmospheric conditions. Detailed results of this study will bereported in the next volume.

124

c

o

;:::;
C1j

c

Q)

u

c

o

U

c

Fig. 2.
Solubility of oxygen in solid silicon.
A: Experimental result; B: Presumably, real
oxygen solubility; C: Presumably, oxygenin linage faults. Initial oxygen concentration of
the sample: • > 1 X 18 18 at/cm 3 ,.... I X 10 17 "-' 1 X 10 18 at/cm 3 ,0 <5 X 10 16 at/cm 3 .

References
1)e.g., Landolt-Bernstein Zahlenwerte und Funktionen aus Naturwissenshaften und Technik,

2)

Neue Ser., UI/17, p. 368, Springer, Berlin (1982).
Y. Yatsurugi, N. Akiyama, Y. Endo, and T. Nozaki: 1. Electrochem. Soc., 120,975

3)(1973).
Y. Itoh and T. Nozaki: RIKEN Acce1. Progr. Rep., Q, 107 (1981).

4)

T. Nozaki and M. Iwamoto: ibid., p. 105.

125

III -3-3.

Rutherford Forward Scattering Applied to the Studyof Hydrogen in Amorphous Silicon for Solar Cell

H. Nagai, M. Aratani, T. Nozaki, M. Yanokura,

1. Kohno, O. KUboi, and Y. Yatsurugi

Measurements of hydrogen concentration and depth profile in solids and thin layers are often of vital
importance, especially in the study of amorphous silicon for solar cells. Rutherford forward scattering measurement can be regarded as particularly useful for this purpose. Using this method with accelerated argon ions as
incident particles, we have obtained hopeful results. 1),2)
Rutherford scattering is nuclear elastic scattering. By the measurement of the intensity and energy-angle
relationship for scattered or recoiled ions, the concentration and depth profile of the element in question can be
known.
Samples were prepared in the Komatsu Electronic Metals Co . by the glow-discharge decomposition ofmonosilane . Amorphous silicon films were deposited on substrate silicon wafers. Several pieces of samples(19 mm X 9 mm) were mounted on an aluminium holder. The arrangement of experimental apparatus is shownin Fig. 1. The scattered and recoiled ions were measured with a silicon detector behind a slit (3 mm in diameter)in a scattering chamber (100 cm in diameter). Incident angle 8 1 and detector angle 8 2 in Fig. 1 can be changed
by remote-controlled movement of the sample holder and the detector, the former being also movable verticallyfor the change of the sample. As the incident particle beam, argon ions were accelerated to 43 MeV (at maximum)by Riken Linear Accelerator. Several tens nA of this beam was focussed (2 mm X 2 mm) and impinged on thesample. Output pulses of the detector were amplified and assorted by a pulse-height analyzer to give the energy
spectrum of the recoiled hydrogen and silicon ions and the scattered argon ions. Optimum measurement condition
under the given accelerator operation was looked for by the change of (J 1 and (J 2' Similar measurements were
4.10 ~----~----~-----'-----'------'-----'-----~

420 nm

3.58

331 nm96 nm
Si

8! : Incident angl e

82 : Det ec tor angle
Li nac

3.07

o
.-<

~ 2.56
c

c

CD

..c

~ 2.05Q)Q

3 1.54

o

u

102

0.51

Channel number

Fig. 1.

Experimental arrangement.

Fig. 2.
Rutherford forward spectra for hydrogen
depth profiling obtained by 22 MeV argon ions.

126

performed for a high-purity silicon crystal as a reference sample without hydrogen, PIQ (polyiminoquinone) films
as a standard sample for hydrogen , and thin films of silicon nitride, silicon oxide and SIPOS (semiinsulating
poly crystalline silicon) on silicon plates.
Some of the spectra are shown in Fig. 2. Clear peaks due to hydrogen are observed. During 70 minutes
irradiation, no notable change was seen in the spectrum. The PIQ film gave somewhat complicated spectrum, andwas not used as a standard for quantitativ,e hydrogen determination up to present. The hydrogen quantity wascalculated from the hydrogen peak area and silicon continuum area in the spectrum in Fig. 2 by the use of thetheoretical recoiling cross sections for hydrogen and silicon ions and their energy losses in the given matrix. 3),4)
The results are shown in Fig. 3. As is understood from Fig. 2 , this method can also be used for hydrogen depth
profiling. Remarkably improved spectrum for hydrogen depth profiling was obtained by the increase of theincident argon energy. The results are shown in Fig. 4. Amorphous silicon films prepared from deuterated
monosilane was also examined. Depth profile of both Hand D can be known simultaneously (Fig. 5).
Studies on the reaction mechanism for the formation of amorphous silicon is now under way by the useof this technique. Further improvement in the spectrum for depth profiling is expected by the decrease of theincident angle 8 1 at a higher argon energy . Rutherford forward scattering method is thus highly effective in the

7

o

c

~

Preparat ion cond iti on
is different \

o

o

5

3

Ci

~
2
OJ)

;:

';.,1
I

Fig. 3.
Hydrogen quantity calculated
500 from the hydrogen peak area and the
T hick ness ( nm)silicon continuum area.

102-- 261 nm
197 nm---- 193 nm- 93 nm0.90------ -077

0.-<::::::-

0.64

Q)

c
c
(1J

..c
u

0.51

ill

0..

~
c

0.38

::J
0

0

026

0.13
o ~----~----~------~----~------~----~----~°
Fig. 4.

Ch annel number

Hydrogen depth profile obtained by 34 MeV argon ions.

127

1 02 .-----.-----.-----,------,-----,-----.-----.
- - - - 680 nm
0.90---- SI077

o:; 064
Q)

c
c

(1J

£
U
Q)

Cl

C
::J

o

U

0.13
O L-----~----~o______L __ __ _~----~------L---~Ch anne l n u m~er

Fig. 5.

Depth profile of Hand D.

study of amorphous silicon films. Since heavy ions suffer large energy losses, they can be used profitably forfine depth profiling. The scheduled characteristics of Riken Linear Accelerator is quite suitable for the present
study. Since hydrogen in other matrices can be measured similarly, this method is applicable to the study ofhydrogen uptake and storage by various materials. From some of our results , this method is shown to be
applicable also to the determination and depth profiling of nitrogen and oxygen.

References
1)

H. Nagai , M. Aratani , T. Nozaki, M. Yanokura, and I. Kohno : Proc. of the 6th Symp. on Ion Sources and2)

Ion-Assisted Technol., p . 221 (1982).
H. Nagai, M. Aratani, T. Nozaki, M. Yanokura, I Kohno, O. Kuboi, and Y. Yatsurugi: Proc . of 26th Ann.

3)

Meet. of Radiochem., p. 46 (1982) .
J . F . Ziegler: The Stopping and Ranges of Ions in Matter, Vol. 5, Handbook of Stopping Cross-Sections for

4)

Energetic Ions in All Elements, Pergamon Press, New York (1980) .
U. Littmark and 1. F. Ziegler : ibid. , Vol. 6 , Handbook of Range Distributions for Energetic Ions in All
Elements, Pergamon Press, New York (1980).

128

III -3-4.

Separation of

119Sb (V), 119mT e(lV), andSn(IV)

by Adsorption on Activated Carbon

S. AmbeWe have been studying separation and purification of cyclotron-produced trace elements byadsorption on activated carbon. Previously, we reported batch-method purification of carrierfree 119Sb(V) by adsorption of impurity Sn(IV) on activated carbon. I) This year, purification of
119Sb by means of column method was studied, since column method is much more convenient
in routine separation. Adsorption behavior of 119rnTe(lV) and milkin~ of 119Sb(V) from 119rnTe(lV)adsorbed on activated carbon were also studied. 113Sn was used as the tracer for Sn(IV).
Shirasagi and No. 2186 (Merck) were used as activated carbons.
One cm 3 of 0.25 mol dm- 3 LiCI solution of pH 6.0 containing 119Sb(V) was put in a column
filled with 200 mg of activated carbon. On eluting with distilled water about 95 % of 119Sb(V)
was collected in the first 3 cm 3 . 113Sn(IV) in 0.25 mol dm- 3 LiCI solution of pH 6 - 7 waspassed through a carbon column of the same size and the column was washed with 40 cm 3 of
0.25 mol dm- 3 LiCl of pH 6.0. The radioactivities in the eluate were less than 1 %, and mostof it turned out to be 125Sb impurity.
These results indicate that Sn(IV) impurity can be removed by passing the 119Sb(V) solution
through a column of activated carbon. In practice, the neutralized 119Sb(V) solution obtained by
the chemical separation procedure described in the previous report 1) is passed through a columnof activated carbon to remove impurity Sn(IV). The carrier-free 119Sb solution thus obtained are
now used for various tracer and Mossbauer studies. 2)
In the adsorption study of 119mTe(IV) by batch method, 100 mg of activated carbon wasadded to 20 cm 3 of LiCl solutions containing 119m Te(IV). After the adjustment of pH, thesuspension was shaken for 1 h at room temperature. The carbon was separated by centrifugation.
The radioactivities in the solutions before and after the adsorption were measured with an NaI
scintillation counter. Effect of pH on the adsorption of carrier-free 119mTe(IV) is shown in Fig. 1.
100

~

t::

0

.......
0..

s...
0
Vl

-0

c::r:

50 _
.-

Fig. 1.
Effect of pH on the adsorptionof carrier-free 119mTe(lV) by 100 mg ofactivated carbon. Adsorption from
20 cm 3 of 0.25 mol dm 3 LiCI solution
by Shirasagi (e), from 0.25 mol dm- 3
LiCl solution by No. 2186 (0 ), and from0.01 mol dm- 3 LiCI solution by
No. 2186(0).

129 .

100

~

c::
0

+-'
0...

so

50

III

"0

c:l:

Fig. 2.
O~~----~--~----~----~~

-8.5

-6.5

-4.5

log[concn.of Te(IV)], mol dm- 3

Effect of concentration on theadsorption of Te(lV) from 20 cm 3 of
0.01 mol dm- 3 LiCI solution by No. 2186
(100 mg).

The adsorption of 119mTe(lV) from 0.01 mol dm - 3 LiCl solution was found to be more efficientin a wider pH range than that from 0.25 mol dm- 3 LiC 1. Figure 2 shows the effect of concentration of Te(lV) on its adsorption from 0.01 mol dm- 3 LiC 1 solutions of pH 7. In Te(lV)solutions with concentrations less than 10- 6 mol dm- 3 , about 95 % of Te(lV) was adsorbed.
Increase in the concentration of Te(lV) above 10- 6 mol dm- 3 resulted in remarkable decrease in
the adsorption of Te(lV). Hence, in adsorption of Te(lV), it is advisable to use a solution
containing small amount of Te(lV) and salts, and sufficient quantity of activated carbon.
The chemical procedure to milk 119Sb from 119mTe described in the previous reportl) consistsof several steps and therefore takes much time. Difference in the adsorption characteristics
between 119Sb(V) and 119mTe(lV) suggests a possibility of milking of 119Sb from 119mTe on
activated carbon. Carrier-free 119m Te(lV) in a neutral solution was adsorbed on the top of acolumn filled with 200 mg of activated carbon and then the column was washed with distilledwater. 119Sb(V) was milked by eluting with distilled water every two or three days. The yield of
119Sb eluted from the 119mTe-column was about 4, % of that of the precipitation method.I)
This rather low yield is ascribed to the adsorptions of 119Sb(III) produced by the EC decay of
119m Te(lV). It was experimentally acertained that carrier-free 119Sb(IIl) is adsorbed by activatedcarbon in contrast with 119Sb(V). About 1 % of 119mTe came out in the first milking solution
but the breakthrough decreased with repetition of milking. The breakthrough was reduced to

0.1 % by using columns filled with 400 mg of activated carbon.
The significant point of this method is that 119Sb(V) is milked from 119mTe(lV)-column bypassing distilled water, to yield 119Sb(V) solutions in a carrier-free and salt-free state.
Further studies are in progress in order to diminish the breakthrough of 119mTe and to raise
the yield of 119Sb.

References
1)

S. Ambe, F. Ambe, and T. Okada: RIKEN Accel. Progr. Rep., li, 112 (1981).

2)

T. Okada, F. Ambe, S. Ambe, and H. Sekizawa: p. 101 in this report.

130

III -3-5.

Mossbauer Emission Study of Defect119Sn

Atoms in Solids

F. Ambe and S. Ambe

Mossbauer emission spectroscopy of 119Sn using cyclotron-produced 119mTe and 119Sb as source
nuclidesl)-3) has been applied in this period to a variety of systems. Here, a study on defect119Sn atoms in non-magnetic solids is reported. Surface studies on magnetic oxides are describedin separate papers. 4 ) ,5) A study on chemical separation of the source nuclides is also reported
elsewhere. 6)
Previously, we reported a systematics concerning the isomer shifts of defect and normal 119Sn
atoms in binary compounds of antimony and tellurium with elements from indium to iodine. 7)
It has now been extended to defect 119Sn arising from 119Sb and 119mTe in compounds with silver
and cadmium, that is, Ag 2Te and CdSb.
Ag 2 119m Te and Cd 119Sb were prepared by fusing a stoichiometric mixture of each metal inargon. Their r,,1:ossbauer emission spectra were measured against a BaSn0 3 absorber at liquid
nitrogen temperature. Details of the measurement were the same as described in a previous
paper. i) Ag 2119mTe gave two emission lines with essentially the same intensity, as shown in Fig. l.
The EC decay of 119mTe to 119Sb can bring about displacement of the decaying atoms in part.
However, the 119Sb atoms are considered to be finally stabilized in the site of Te on the basis ofan electronegativity consideration.1) We assign, therefore, the two lines to a quadrupolar doublet
with an isomer shift of 2.27 mms- i . Cd 119Sb gave a slightly asymmetric doublet with an isomer
shift of 2.10 mm s-l. Combining these results with the data reported previously,?) we obtain
Fig. 2 which shows the relation between the isomer shifts of defect and normal 119Sn and theatomic number of their nearest neighbor atoms.

100

1::
(f)

c

2

c

Q.J

>
cu
Q.J

~

99

Relative veloc ity (mm S - 1 vs BaSn03 )Fig. 1.
Emission Mossbauer spectrum of Ag 2119mre
at liquid nitrogen temperature.

131

Starting from the compounds with the most electronegative iodine, the isomer shift is seenfrom Fig. 2 to decrease with the decrease in electronegativity of the nearest neighbor atoms
irrespective of the different crystal structures and types of bonding. However, it can be concluded
from the present results on Ag 2 119m Te and Cd 119Sb that the decrease in isomer shift saturates fornearest neighbor atoms with atomic numbers smaller than that of tin. Namely, 119Sn atoms withligands more electropositive than tin show an isomer shift value around 2.1 mm s-1. The
exceptionally low isomer shift for 119Sn in the Te site of In2119mTe3 can be ascribed to thestructure of the compound with vacancies.
In this way, Mossbauer emission spectroscopy is a useful technique for studying the electronic
state of atoms in unusual chemical environments. Further studies on various other solids, suchas the Sn-S system, are now in progress.

4I"

if)

E
E
0 '"
c

0

11

12
013
.9
010

-

Isomer shifts of defect and normal
Fig. 2.
119Sn in binary compounds of antimony andtellurium with elements from silver to iodine .
Open circles refer to defect 119Sn in emission
measurements and close ones to normal 119Sn

31.7

if)
CD

OJ
if)

>

I-

01

.-

..r::
if)

~
E

05
06

02

2t-

08

03

0

J:2

04
I

1

I

I

I

I

I

47

48

49

50

51

52

53

Atomic number of the nearest neighbor atoms

in absorption measurements.
1. Ag 2119m Te, 2. Cd 119Sb, 3. In 119Sb,
4. In 2119m Te 3, 5. Sn 119Sb, 6. Sn l19m Te,
7. SnSb, 8. Sb2119mTe3' 9. SnTe,
10. 119Sb2Te3, 11. 119SbI3, 12. SnI 2 ,13. 11 9m TeI 4 .

References
1)
2)
3)
4)
5)

F. Ambe and S. Ambe: J. Chern. Phys., 73, 2029 (1980).
F. Ambe and S. Ambe: ibid., 75,2463 (1981).
T. Okada, S. Ambe, F. Ambe, and H. Sekizawa: J. Phys. Chern. , 86,4726 (1982).
T. Okada, S. Ambe, F. Ambe, and H. Sekizawa: p.98 in this report.
T. Okada, F. Ambe, S. Ambe, and H. Sekizawa: p. 101 in this report.

6)
7)

S. Ambe: p.I28 in this report.
F. Ambe and S. Ambe: IPCR Cyclotron Progr. Rep., 14, 96 (1980).

132

III -3-6.

Research Proiect on Coulomb-Excitation Mossbauer

Spectroscopy Using Heavy Ions Accelerated by RllAC

F. Ambe, K. Asai, N. Sakai, and A. Hashizume

We have been studying application of Mossbauer spectroscopy to solid state physics andchemistry making use of short-lived radio-isotopes produced by the cyclotron.1)- 3) Now that heavyion beams are available from RILAC, a variety of on-line .Mossbauer spectroscopic investigations
utilizing Coulomb excitation are planned in the following fields:(1) Study of the physical and chemical behavior of energetic atoms in alloys and semicond uctors ;(2) Study of the structure and electronic state of inorganic, organic and biologicalcompounds;(3) . Study of magnetic materials.
For the time being, 57Fe, 61Ni, and 73Ge are listed as the candidates for Mossbauer nuclides
to be investigated. Search for a new Mossbauer nuclide will be also made.
Preparatory experiments have been already started. A few examples of Coulomb-excitationinduced')'-ray spectra observed with a 37 MeV Ar4+ beam are shown in Fig. 1.
A design for a thin-window chamber equipped with a heavy-duty Mossbauer spectrometer is
now being worked out.

>Ql
(a )

Fe-57

.:s:.

Ql

C
C
C'Cl

-c
U

'-....

J]
C
::::l

co

o

oj
ill

U

>Ql

(b )

Ge - 73.:s:.
LO

Fig. 1.
Coulomb-excitation induced,),-ray spectra of (a) iron (the 14.4 keV
Mossbauer ')'-ray is not recorded becauseof absorption by the window of thechamber, and the 126.0 keY ')'-ray is
ascribed to impurity manganese in thetarget) and (b) germanium targets
observed with a 37 MeV Ar4+ beam.

Channel nu mbe r

An intrinsic germanium detector was
employed.

133

References
1)

F. Arnbe and S. Arnbe: J. Chern. Phys., 73, 2029 (1980).

2)
3)

F. Arnbe and S. Arnbe: ibid., 75,2463 (1981).
T. Okada, S. Arnbe, F. Arnbe, and H. Sekizawa: J. Phys. Chern., 86, 4726 (1982).

134

III -4.

Radiation Chemistry and Radiation Biology

1.

Spectroscopic Studies on the Electronic Excited States
Formed at High Density in Heavy-Ion Track

K. Kimura, Y. Toda, and M. Imamura(1) Decay and time resolved spectra of u- excitons in alkali halides
We have previously found that the emission-intensity ratio of u- to 1T-excitons in C-ion irradiated KBr
single crystal is 5 times larger than that in VUV -light or x-irradiation. This enhanced ratio was ascertained not
due to enhanced radiationless relaxation of the 1T-excitons because of the invariant lifetime of 1T-excitons with
LET change. I) Therefore, this enhanced ratio may he attributed to an increase in yield of u-excitons or
acceleration of their radiative second-order decay in dense heavy-ion tracks.
To ascertain that, the decay of the u-excitons was measured by a single-ion hitting and single-photon
counting method which has ns time-resolution. The decay rate was found to be of the first order and not
shortened with increasing LET. It was, therefore, concluded that the enhanced emission-intensity ratio by highLET irradiation is attributable to the increase in yield of u-excitons. 2 ) This fact suggests that the present LET
effect is interpreted as the effect on the formation processes of u-excitons, i.e., the relaxation process of free
excitons which are shortlived « 10-12 s) precursors of the u-excitons. The free excitons formed at highdensity along heavy ion-tracks may produce more u-excitons by interaction than in photo-irradiation whereu-excitons is produced only by spontaneous relaxation of free excitons.
The conclusion mentioned above was further confirmed by measurement with RbBr and KI single crystals.
The decay times of u-excitons, r: I' in C-ion and photo-irradiation are listed in Table 1, in which unidentified
longer lifetimes, r 2' which were found simultaneously at the same wavelength as did for u-excitons, are also given.
Time-resolved emission spectra have no indication of new band due to r 2' Typical emission spectra for RbBr
are shown in Fig. 1.
A new detector system with 100-ps resolution will be completed soon and used for more detailed studies
on this problem.

1.0
M

0
~

0.8

X
<f)

c
0

0.6

+-'

0

...c
CL

4.20
eV

135

Table 1. Lifetimes of a-excitons.
Ions

Samples

Temp.(K)

Wavelengthr 1 (ns)r 2 (ns)

Intensity ratio

e 6+

KBr

4.5

285

3.7

16.9

10.0

It"

KBr

5

280

3.3

17.0

10.0

e 6+

RbBr

4.5

304

2.7

16.9

27.5

It"

RbBr

5

300

3.0

13.0

4.0

e 6+

KI

4.5

306

3.1

23.3

13.6

W

KI

5.

300

2.3

Data for H+: I.M. Blair et al., AERE - R6906.

00 00...... 1"-..
LD LD

(a )

(h )

~~

0

I"-..
01
N

~

~

I"-..
~

II

U)
I"-..
M
U)

I

LD
"<j"
LD
U)

I

6.1 K

M

MN 0
I"-..U) LD
0001 0"<j"~ LD

M
M

0
I"-..

I

N
LD
M
I"-..

I

7.0 K
6.2 K

(Y)OO"<j" MLDLDU)OOMNOON
00000100 ......
LDLDLDU)U)U)N OOM...... 01"-..
0100

I"-..
~

N

11 1111

7.0 K

14 K

22 K

Fig. 2.

Temperature dependent emission spectra of helium irradiated by 95 MeV

N-ions. Spectral intensities are normalized to the irradiation dose of 5.9 ne (or2.7 X 109 ions).

(2) Emission spectra from Helium irradiated with 95 MeV N-ions near critical temperature
The emission spectra of He gas irradiated by N-ion near critical temperature were found to show different
features in some respects compared with results reported for microwave-discharged helium at room temperature: 3)(i) temperature effect on the spectra, (ii) pressure effect on the emission intensities , and (iii) surface effect.
The emission spectrum obtained by 95 MeV N-ion irradiation at 6 K is well resolved as shown in Fig. 2,
although their peaks were not so sharp as atomic spectra.

Most of the peaks can be identified with those ofhelium excimers. The spectrum shows marked variations with temperature. The peaks in the short wavelength
region at 6.2 K shown in Fig. 2(a) mostly disappear at 22 K, whereas the peaks in the long wavelength regionin Fig. 2(b) change in a drastic and complex manner. The peak at 6376 A strengthens rapidly on going from 6.1
to 7.0 K, but then decreases with wavelength shifts with further increasing temperature accompanying growth of
new peaks.
Marked pressure dependence of the emission intensity was also observed. The peak intensity at 6376 A
becomes 250 times when the volume of He gas increased 16 times in a cryostat, as shown in Fig. 3. This
volume change corresponds to the pressure change from 200 to 3000 Torr at room temperature. Our result is

136

300

~

250

-+-'

c
:J
>,

'"<U
'"-

Ll
'"-

«

200
150

c
0
(f)
(f)

E
W

100
50
0

Fig. 3.

0

•

5
10
15
1000 tor r
2000 tor r
Pressure
Pressure dependence of emission intensity of6376- A peak.

far different from Collins and Robertson's result obtained by microwave discharge at room temperature; theyreported that the maximum intensity is observed at 30 Torr.
The emission was observed to be intensified whenever some surface is present in the beam trajectory area.
These unexpected features of the emission spectra are supposedly related with the phase conditions near criticaltemperature and with the exciting source. Further studies are being carried out bearing these points in mind.

References
1)
2)
3)

K. Kimura and M. Imamura: Phys. Letters, 67A, 159 (1978).
K. Kimura, M. Mochizuki, T. Fujisawa, and M. Imamura: ibid., 78A, 108 (1980).
C. B. Collins and W. W. Robertson: J. Chern. Phys., 40, 2202 (1964).

137

III-4-2.

Application of Thermoluminescence Dosimeter for
Dose Measurement of High-LET Radiation

F. Yatagai and K. Nakano

Both an accurate dosimetry and a uniform irradiation are required for investigating various
effects of high-LET radiation on biological materials. For the purpose of uniform irradiation,
elastically scattered beam at a certain angle with respect to a beam axis has been used in the
biological-irradiation system of IPCR cyclotron (Fig. I).
(4) (5)
Vacuum8 1 =2° 45'
8 2 =6°00'

Chambe r

(3)

( 5)

(7)

(7)

Fig. 1.
Scheme of the apparatus for biological irradiation.
(I) Slits, (2) Scattering foil, (3) Solid state detectors,(4) End of vacuum window, (5) Sample wheel, (6) Faraday cup,(7) Vacuum window, (8) and (9) Sample holders for low- or
high-dose irradiation, respectively, (10) TLD ribbon (LiF700).
Thermoluminescence dosimeter (TLD, Harshow Model 2000) was employed to examine
whether or not this irradiation system provide a uniform irradiation. A fairly good uniformity(± 10 %) was obtained in the area of surface of sample holder when TLD ribbons (LiF700),
0.25 mm in thickness, mounted on the holders were rotated during irradiation with N ions (4.7
MeV /amu) (data, not shown). A small fluctuation in TL response was also observed among the
TLD ribbons mounted on different holders, which were located on the circle of scattering angle() = 6°00' (Fig. 2). Although the data was not shown, similar fluctuation was observed for thecase of () = 2°45'. These fluctuations seem to be caused by the small difference between the
beam axis and the center of apparatus.
Determinations of dose-response curves for biological samples are usually carried out by
eliminating such fluctuations with either of the two methods as follows. One of them is to assay
the biological activity for each dose after mixing all the samples irradiated at the four different
windows. The other is to circulate the sample holders from window to window during irradiation
so that total dose for each sample will be given by fractionated irradiation at the four different
windows (Fig. 3).
As can be seen from the dose response curves of TLD ribbons in Fig. 3, TLD is available
to monitor the dose of high LET radiation.

138

o

~ S~;)h Ide r
0---t-+---tl--t- -l-----+-t-'-t

:

;

1.0

U?
C

o

Q)

o

U?

Q)
-+-'

C

Q)

U?

...s

0
0..

>
.~

TL D- ribbonoQ)

q: 0,5(i) -.J
0:::1-o ~----~------~----~~----~--

Sample whee lSample holder No.

Fig. 2.
Fluctuations in TL response among the TLD ribbons
mounted on different holders (scattering angle () = 6°00').
TL response for each TLD ribbon irradiated with N ions (4.7
MeV /amu) is expressed in the relative value .

L ow- dose

Irrad iat io nHigh - dose

Irradiation

Sample wheel
I"I, ....

~I

I

/~

200
0

z:

Q)

U?

C

0
0..

U?

100

Q)

0:::
-.J
I-

0

Fig. 3.

./

•

./

3
2
Input Ch arge for Faraday
Cup (/1 C)

\

/

U 15
:::z

Q)

U?

C

0

10

0..

U?

0:::
-.J
I-

/'

•

Q)

5

0
Input Charge for
Faraday Cup (/ 1 C)

Dose-response curves of TLD ribbons (LiF700) .

TLD ribbons on the sample holders for low- or high-dose
irradiation, corresponding to (8) or (9) in Fig. 1, respectively,
were exposed to N ions (4.7 MeV/amu). Total dose for each
TLD ribbon was given by fractionated irradiation at the four
different windows (see text).

139

III-4-3.

Track Structure Theories and Inactivation Cross Sectionsof Bacterial Spores for Heavy Ions

T. Takahashi and F . Yatagai

Precise evaluation of the dose around the path of an ion is prerequisite for a better understanding of inactivation of bacterial spores. We have calculated Katz's close-collision dose, Ahlen'sdistant-collision dose and Chatterjee-Schaefer's dose in water. We have also examined whether
they are consistent with the stopping power.1) In Fig. 1 are shown Katz's dose and Ahlen's doseand in Fig. 2 are shown Katz's dose and Chatterjee-Schaefer's dose for comparison. The energy
dependence of the inactivation cross sections of]!. subtilis spores for ions carbon through neon is
only slight and the mean cross sections for C ions (0.6 - 4.1 MeV /amu), 0 ions (0.8 - 1.1
MeV/amu) and Ne ions (2.2 - 3.7 MeV/amu) were found to be 0.22 , 0.23, 0.26, and 0.33 JIm 2,
respectively (Fig. 3).

""E
(,)

.......
U)

JI0

4

N

*"!:::!

d 103

10
(4)

10-7
X (em)

Fig. 1.
Solid lines are Katz's
close-collision dose and dotted lines
are Ahlen's distant-collision dose.
Z* is the effective charge ofheavy ion.

10-5

X (em)

Fig. 2.
(1) Katz's dose for{3 = 0.05; (2) Chatterjee-Schaefer's
dose for {3 = 0.05; (3) Katz's dosefor (3 = 0.15; (4) ChatterjeeSchaefer's dose for {3 = 0.15.

140

To interpret these results, analysis was carried out along lines similar to Katz's target theory
but the parameters were chosen so that they have an experimental basis and are different fromthose used by Katz, since Katz's original parameters could not account for the survival curve of
the spore for gamma-rays.2) The area of '&sensitive element" rra 2 in Katz's target theory waschosen so that it corresponds to the spore core area (0.22 JIm 2 ), and we assumed that one target
has one sensitive element in case of the spore, in contrast to Katz's original paper. Furthermore,
we introduced a new idea to separate out the effect of delta-rays, as will be described below.
If we assume the whole spore core is a target and is a short cylinder of radius a whose axis
is parallel to and at distance r from the path of an ion, the inactivation cross section is expressed
as

where
P.m = 1 - exp( - D(r)/E.III ),

r<a

and
r>a
Here, Pin is the probability that the spore is inactivated when the ion impinges upon and goes
through the spore core. Ein corresponds to the dose at which there is an average of one hit per
target when the nucleus of the ion hit the spore core. Po is the probability of inactivation when
the ion passes by the spore core and the trajectories of its delta-rays come into the spore coreand Eo is the 37 % survival dose for delta-rays. D(r) is the mean absorbed dose by the target
which is given in an analytical form in Ref. 1.
Experimental inactivation cross sections are in fairly good agreement with the theoreticalestimates for N ions, if we assume Chatterjee-Schaefer's dose and appropriate values are chosen
for Ein and Eo. These values are found to be Ein = 10 krad and Eo = 40 krad as shown in Fig. 3and discussions on them are given in Ref. 1. For U ions,3) experimental cross sections are larger
1.2

" c

" N

-

<3

N~ 1.0

(I lU

•
o

c
0

U 0.8
<1>

(SlU

(f)
Vl
Vl

0

U 0.6
o·

c

.2

.~ 0.4 c.

o

t:i
o
c

-

0

02

.J!;.t!\ c.. ~~0-. ' diO.~-<-~,--(2l

'~(4l

o

o

2

4

'

(6)N

6

8

Energy (MeV/omu)

10

0

Ne
Pb Ref . 3

U

Fig. 3.
Experimental and theoretical
inactivation cross sections for Bacillus
subtilis. (1) - (7): Calculated by using
Chatterjee-Schaefer's dose. (1) U ion,
Eo = 40 krad, Ein = 10 - 40 krad; (2) Nion, Eo = 40 krad, Ein = 10 krad; (3) Nion, Eo = 40 krad, Ein = 15 krad; (4) Nion, Eo = Ein = 40 krad; (5) U ion,
Eo = 63.5 krad, Ein = 10 - 63.5 krad;(6) N ion, Eo = Ein = 63.5 krad.
(Experimental 37 % survival dose for
gamma-rays was found to be 63.5 krad.)141

than the theoretical values as seen in Fig. 3. The discrepancy may be ascribed to "long range
effect" as previously pointed out. In the course of analysis, we used the dose of Katz and Ahlen
as well as that of Chatterjee and Schaefer. For U ions, calculations based on Katz's dose or
combination of Katz and Ahlen's dose yielded slightly larger inactivation cross sections than those
based on Chattetjee-Schaefer's dose, but the difference is not so large as to draw different
conclusions. 1)

References
1)

2)

T. Takahashi, F. Yatagai, and S. Kitayama: Life Sciences and Space Research, Pergamon
Press, London (1982); T. Takahashi, F. Yatagai, K. Aoki, and S. Yamanaka: Hoshasen(Ionizing Radiation), ..2., 24 (1982).
T. Takahashi, F. Yatagai, and A. Matsuyama: Sci. Papers I. P. C.R., 74, 51 (1980).

3)

M. Schaefer, R. Facius, K. Baltschukat, and H. Bucker: 7th Symp. on Microdosimetry (1980).

142

111-4-4.

Mutagenesis of Chinese Hamster V79 Cells by
Nitrogen Ion Beam

1. Kaneko, G. Okada, K. Nakano, and T. Nishimura

Mutagenesis is one of the most important biological effects of the ionizing radiations and isconsidered to be the first step for carcinogenesis. Although one of the potential medical
application of heavy ions is its use in cancer therapy through effective killing of cancer cells,
irradiation of normal tissue near the site of cancer might result in new carcinogenesis in later
years after irradiation of the primary cancer. The purpose of the present study is to establish amethod of detection of mutagenesis and to obtain a dose-effect relationship for assessment ofmutagenic potential of heavy ions beams.
Most of previous studies of mutagenesis on mammalian cells have been carried out mostly
with low LET radiations (X and gamma rays) and only a few work has been available with heavy
ion beams. In the present study, a 6-thioguanine resistant marker (considered to be deficiency
in hypxanthine phosphoribosyltransferase), the most frequently used one among several markers,
was used for comparison with the work of others.
Chinese hamster V79 cells in exponentially growing phase were used. The cells attached toPetri dishes were irradiated with nitrogen ions (65.8 MeV/nucleon, N4 +, LEToo '" 392 keV/um) at
a dose rate of approximately 1.8 Gy /min or with gamma rays from a Cobalt 60 source at a dose
rate of 1.4 Gy /min both in air. Immediately after irradiations, the cells were trypsinized anddivided into two portions. One was plated for colony formation to estimate its surviving fraction.
The second portion was plated and incubated for five days. Then, they were trypsinized andplated for mutant colony formation in the 6-thioguanine containing medium. Figure 1 showsthat a dose-effect relationship of mutagenesis for 6-thioguanirie resistant marker by nitrogenbeams was of curve-linear type, similar to that of gamma rays. However, induced mutation
frequency per unit dose for nitrogen beam seems to be much higher than that for gamma rays.
When a gamma ray dose of 6.5 Gy to give 10 percent survival is used for a reference point forRBE estimation, RBE of cell killing for nitrogen beam vs. gamma rays was 1.3, while RBE of
14

o

o
o

12
10

'"b
~

8

•

1G
u
Q;

::0

6

.~

>

u; 4
0...

LL 2

2:

0
0

3
Dose (Gy)69Fig. 1.
The effect of nitrogenion (65.8 MeV/n) (0-0) on
mutation in Chinese hamster V79
cells, as compared to ,),-rays (. -.).

143

mutagenesis was 1.9 (Table 1). This indicates that nitrogen beam of 392 keY fum induced
mutation more effectively than cell killing.
Table 1. RBE value for cell killing and mutation induction for nitrogen ions.
RB E

Cell

Inactivation(10 % survival)

Mutation induction(6 '" 7 X 10-5 )H F 19
V 79

1.7
2.5

2.8
5.3

V79

1.3

1.9

Cox et al.l) (1977)

Reference
1)

R. Cox, J. Thacker, D.T. Goodhead, and R. J. Munson: Nature, 267, 426 (1977).

144

1II-4-5.

Recovery from Potentially lethal Damage of Human
Cultured Cells after Irradiation of Nitrogen Ion Beams

I. Kaneko , T. Ohno, K. Eguchi, T. Inada,

G. Okada, and K. Nakano

Irradiation with high-LET charged particles may be an effective therapy for solid malignant
tumors. Many investigations have been done on tumor cell inactivation after irradiation withhigh-LET radiation, however, there is no concrete evidence regarding the extent of recovery frompotentially lethal damage (PLD) in human normal and tumor cells after irradiation with highLET particles.
Because of discrepancies in the results hitherto obtained regarding the recovery from PLD
in tumor cells after irradiation with neutrons and charged particles, recovery from PLD in normal
human lung fibroblasts and radiation resistant human melanoma cells after irradiation withnitrogen ions accelerated in the cyclotron and 60Co 'Y-rays was examined.
Cultured human normal fibroblast IMR 90 cells and HMV -1 cells from human melanoma
were grown up to their saturation density. The recovery from PLD was observed after thenitrogen ion irradiation, but the extent was less than that after 'Y-irradiation. Ratios between
DoS (the dose required to reduce the number of clonogenic cells to 37 % of their former value)
before and after the 6 h incubation at the saturation density of IMR 90 cells were 1.1 and 1.8
for nitrogen ion beams and 'Y-rays, respectively. The half maximum time in IMR 90 cells was
3.1 h after nitrogen ion irradiation while it was l.3 h after 'Y-irrandiation (Fig. 1). The half
maximum recovery time in HMV -1 cells was 7 hand 5 h for nitrogen ion beams and 'Y-rays,
respectively. For nitrogen ion beams, dose dependency of the recovery from PLD was not observed
although it was observed for 'Y-rays. These results suggest that the recovery from PLD in humannormal and tumor cells may be virtually identical between low- and high-LET irradiation but
practically appear with a large difference in the mean recovery time and the recovery ratio of
initial damage after irradiation.

cou

1/r---

~O .l

~
~

~

Q~

Q

-----1.- _---I- - - -- I~

Fig. 1.
Time course of recovery frompotentially lethal damage after irradiation
with nitrogen ion beams and 60Co 'Y-rays
in normal human fibroblasts, IMR 90.
Plateau-phase culture of IMR 90 cells were
irradiated with nitrogen ion beams and 60Co
'Y-rays. Division ages of the cells and doseof the irradiation used were 36 PDL and
3.6 Gy for nitrogen ion beam irradiation(e) and 39 PDL and 5.2 Gy for 'Y-irradiation

O. 010~-------'-2---'-4-----'-6---8L--...J

Recovery time (hr)(0 ), respectively. Vertical bars are standard

deviation of mean 4 dishes.

145

--

III -5.

Miscellaneous1.

Quantitative Trace Analysis byParticle Induced X-Ray Emission

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

In order to establish a rapid and reliable method for quantitative trace analysis by particle
induced X-ray emission (PIXE), preliminary experiments were performed and computer programs
to analyze the PIXE spectra were made.
Samples supported by thin Mylar films were irradiated with 3 or 5 MeV /amu H+ and N4+ions accelerated by the cyclotron. X-ray signals detected by a Si(Li) detector were processed bya multichannel analyzer and recorded on a paper tape or a floppy disk. The acquired PIXE
spectra were treated off-line by F ACOM M-200 computer to obtain the element concentrationsin the samples. The experimental set-up and the detailed descriptions of the computer programs
are reported in Ref. I.
Samples used here were 25 specimens of blood serum collected from various diseased persons,
12 specimens of healthy human whole blood and two standard materials (bovine liver-NBS
biological reference material and a mixture of chemical compounds of known concentrations).
The elements observed in blood serum and whole blood were P, S, CI, K, Ca, Fe, Cu, Zn, and Br.
Minimum detection limit for each of these elements is arround 10-8 g under the experimental
conditions (sample amount: I ME, incident beam: 5 MeV H+, beam current: 5nA, distance
between the target and the detector: 80 mm , detector: ORTEC 7866S). While any significant
differences in the element concentrations could not be detected among the healthy whole blood
samples, the element concentrations in some diseased blood serum samples showed marked
changes. For example, an increase in copper content was observed in a blood serum sample takenfrom a patient with parathyroid disease (Cu in normal human blood serum: I Mg/m'£). Figure 1
shows the PIXE spectrum of this case.

(}.Ig/m1)

Cl
S

10

4

r-

OJ
t:
t:

'"
.s:::
u

10

3

;.

p.::'.
., . K Ca
r

P

250
1000
C1 2100
100
K

S

Ca
Cu

40

~

OJ
0.
Vl

.... 10 2
t:
::I
0

u

10'
23455789
X-ray energy (keV)

5 MeV H+ induced X-ray
Fig. 1.
spectrum of a blood serum sample takenfrom a patient with parathyroid disease.
The solid line shows the continuum
background radiation.

146

Statistical treatment of the data obtained from a great many samples is necessary to findthe correlations between diseases and elemental contents in biological tissues. Now we areconstructing a target chamber for PIXE, which is equipped with an automatically changeable
multiple sample assembly and is to be connected to Linac. PIXE spectra induced by heavy ionsaccelerated by Linac were also measured by using the target chamber for X-ray angular
distribution measurement,2) One of these spectra is shown in Fig. 2. The preliminary measurements proved that Linac can be used for PIXE analysis.
4

10

P

K

:: S .-

lO3

Si. \. C1 .: Co
'.'

<D
c
c
0

.c

#'

10

2

......

j

..

'

'..:

u

"-

Q)

0.
(/)

+-'

c

10

1

::J
0

u

10°
2

6

x-ray energy (keV)

810Fig. 2.
X-ray spectrum of bovine liver
induced by 10 MeV C2+ ions accelerated
by Linac.

ReferencesI)
2)

K. Maeda and M. Uda: Reports I.P.C.R., (in Japanese), 58, 96 (1982).
Y. Awaya, 1. Takeshita, Y. Tendow, and T. Katou: IPCR Cyclotron Progr. Rep., 14, 70(1980).

147

N.

ACCELERATOR DEVELOPMENT

1.

Beam Attenuation Method Using
Charge Transfer Reactions

M. Kase and T. Kambara

When one wants to know the energy spectrum of a beam or the time information of aparticle in the beam, at the RILAC, a simple and accurate way is to measure them with a surfacebarrier-type semiconductor detector (SSD) which is set in the beam line. During the measurement,
however, one has to weaken the beam current down to a level as low as 10-16 '" 10-17 particle
amperes in order to prevent the radiation damage on the detector. To get such a weak beam, thebeam attenuation by a factor of 10-6 is required.
For the accurate measurement of energy, one needs to keep the beam quality the same as
before the beam is attenuated. If one reduces the beam intensity by changing the beam transport,
there is a possibility that a stray beam, such as scattered beam, is led to the detector. Therefore,
one has to maintain the settings of magnetic devices (Q-magnet, steering magnet, etc.) unchanged.
At the ion source, limiting the arc power, one can attenuate the beam by 10-1 '" 10-2. On theother hand, the beam attenuation of 10-3 can be obtained by inserting, into the beam line, thethin copper plates with many small apertures (0.3 mmcp). Anyway, an additional device is needed
for the further beam attenuation.
The method using two sequential charge transfer reactions in the injector beam line is very
easy to do and needs no special instrument, providing a stable and controllable attenuation by afactor of 10-5 or less. All one has to do is change of the setting of the bending magnet (BM 1).
Figure 1 (a) shows the normal beam trajectory of ions represented as Xn+, when a couple ofdipole magnets (BM 1 and BM2) are adjusted at the same field Bo' The charge changed
components which are produced through collisions with the residual gas in the beam pipe, areremoved by BM 1 and BM2. When the magnetic field of BM 1 is changed from Bo to (:-1 ) Bo 'the situation becomes as shown in Fig. 1(b). First, the main beam Xn+ is removed by BM 1,
and instead, x(n-1)+ ions, which are produced as the result of single electron capture in thesection from A to B, are introduced to the next stage of beam line. Next, xn+ ions, which areproduced as the result of electron loss in the section from C to D, are introduced by BM2 tothe cavity # 1 of the linac. Consequently, the Xn+ beam at the entrance of the cavity # 1 isdecreased extremely through the two sequential inverse charge transfers.
The attenuation ratio, ~, depends on the kind of ion (X and n), the beam energy, thecontents of residual gas, and their densities (or pressure, p) in the beam pipe. In the case when
Ar4+ beam 0.1 MeV) is used and the average vacuum pressure, Po' in the beam pipe is 5 X 10-7
Torr (N 2 equivalent), ~ becomes 6 X 10-5 . Since ~ is roughly proportional to P02, one can adjust~ by changing po'

The beam quality is changed slightly through the attenuation process. A beam emittance is

148

BM 1

(a )

Xn +

-+

Inj ec t or

:fj: 1 Cavi ty

BM 1
(b )

\

B

Injec t or

Fig. I (a) The beam trajectory ofA

ions, X n+, in the normal operation.
Magnetic fields of both bending
magnets, BM I and BM2, are Bo'(b) The beam trajectory when thefield of BM I is changed to:fj: 1 Cavityx(n - 1 ) -(n~l )Bo.

increased due to momentum transfers by the two sequential reactions. But it causes no effecton the energy spectrum of the linac output beam, because the slit system of the injector beamline limits the emittance of beam injected to the cavity # 1.
One can use other charge transfer processes for the beam attenuation. For example, theprocess, X n+ ---+ X(n + 1)+ ---+ X n+, or X n+ ---+ X(n- 2)+ ---+ X n+, etc. can also be used. Though they canprovide a smaller value forr, the beam quality becomes worse.

149

N -2.

Design of Axial Extraction PIG-Source

K. Hoshino(1) Construction of ion source
An Ion source of linear accelerator to produce multiply charged metal ions from non-corrosive organometallic
compounds which have relatively high vapour pressures has been constructed. The ion source was designed
considering the following requirements: the gas pressure in the beam path should be maintained sufficientry low
to prevent loss of multiply charged ions by charge exchange collisions with residual gas molecules; potential
distribution in the ionizing region should be such that the impinging ions on the filament are reduced to minimize
consumption of the filament.
The central part of the ion source is shown in Fig. I and overall construction in Fig. 2. The ion source
housing is set in a solenoid. The central part is constructed with electrodes A, B, C, D, E, and F. The central parta of electrode A has a hole of dia. 3 mm. The construction of B is such that part b can be replaced easily,
because b is eroded by sputtering by the beam. The potential of electrode E is kept higher than the potential ofelectrode D to repel the positive ions back to the ionization region C. Electrode D has a channel h through whichgases are introduced from gas supply. Gases are blown out from the circular slit of h into the cavity of D. The
construction of the slit is designed to form a gas jet and send most of the gas to the outside region of C throughthe gap between C and D. Ions produced in the cavity are accelerated by the electric field between theelectrodes C and D. The strength of the electric field is adjustable.

1OkV + ( 1. 65-1.9kV)j

10kV+12V

I

cFig. 1.

Schematic diagram of the main part of axial extraction PIG-source and potential distribution.

F is the filament. The potential of B is kept lower by 12 V than that of F, so that all of the electrons
emitted from F are sent back without hitting the surface of B.
It is necessary to prevent ions from impinging on the surface of the filament. Potential of the electrode E
is set higher by 50 V than that of D. The gas flowing through the slit of h forms a jet stream and most of gas
is sent to the gap between C and D, but a part of it moves toward F. It is intended to reduce the gas pressure
between E and F by providing evacuation slots in E. As the distance between the electrodes E and F is small,
it is expected that not much ions are produced between E and F. Therefore the number of ions impinging on F
is not large. Potential difference between electrodes C and D can be set at a value between 0 and 250 V. It is
hoped to increase the multiply charged ions by making transit time of ions, hence confinement time in theregion C, moderate by use of small potential difference between C and D. When the organometallic compoundhas not enough vapor pressure to produce the ions of metal of concern, the elemental metal may be used
applying sputtering scheme. For that purpose, a target b made of the metal can be inserted in the central partof B. It is necessary to drill a hole of dia. 3 mm at the center of B to provide the passage for the ions. Inertgas will be used to help sputtering of metal from b.
Figure 3 shows the construction of the ion source. The ion source is cooled by deionized water. The
cooling water is circulated through holes of supports. The supports between electrodes are steatite pipes.

150

Ion source vessel and solenoid.

Fig. 2.

CD Solenoid, WIon source, ® Ion source housing.
Each section of solenoid has a winding of 304 turns of 2.4 mm X 2.8 mm PVF coatedwire, and they are connected in parallel. The resistance of the solenoid is 0.076 n.
Magnetic flux density at the center of the solenoid is 1000 G for the solenoid
current 100 A, and the wattage consumed by the solenoid is 760 w.

r--

,~

-'::"""'~ .-1"1''t±::l

.-

~~~-

-

-

" : ~--- ~I

.--If

- "-r

_
------ ..._---'"
n- P.r r:.m:+~ -lfr==n W~ ~ ti{jiliUT ' IT rf IT r
W-U ~J-r:::::::::::..
~ -=-~
----

f--

c

-

_

Hf

'..II

~ ~~

~

li'~

-~":l.

:i~-,....,.,.........

1tir

1

I L

c--

..R=1

--

~

--

'U

--

---

,r

l

--

~-~

-

r..: .. _-------- : -_:.i""'U "
~

~

~~r=

Fig. 3.

1"-

Construction of axial extraction PIG-source.

-l:ti~ n----..
"

~
Iri:'
I

"1: - - - f-t

416

g

,r
,

.If"""""

'lLJ

--

-

-

-

... -. ..... -~~Ji----II~151

On the other hand, gas passage is heated up by electric current to prevent the condensation of theorganometallic compound.
Figure 2 shows the construction composed of solenoid, ion source, and ion source housing.
(2)

Detection of ions

It is impossible to eliminate the large distribution of velocity of ions produced in the axial extraction PIG

magnetic analyzer

E

=
'--'

slit
noble gas ion pump
(201)

Fig. 4.

Plan view of double focussing mass spectrometer.

Table 1.

Specification of double focussing mass spectrometer.

LC">

E
'-'

=
S

Radius of the orbit
Electrostatic analyzer

Deflection angle{ Gap between the electrodes
Max. potential difference between

15 cm
60°
1 em
1670 Vthe electrodes
Deflection angle

15 cm
90°

Max. power

150 W

The position of the two images ofSymmetricalRadius of the orbit
Magnetic analyzer

Arrangement{ Max. flux density{

10.7 kG

the electrostatic analyzer
The position of the two images ofSymmetricalthe magnetic analyzer
Width of slit

Mass range

j
J

\

Slit

1

0.2 mm

Slit

2

1 mm

Slit

3

0.8 mmM/e max . = 100

at ion accel. voltage of 12.5 kV

M/e max . = 125

at ion accel. voltage of 10 kV

152

ion source. Most of the ejected ions are produced in the narrow region between C and D where potential
variation is relatively small. As the potential difference between electrodes A and E is about 12 kV and the
maximum potential difference between C and E is 300 V, the resolving power for the distinct peaks of themass spectra of ions can be made larger than 40 by the use of a mass spectrometer composed of magnetic
analyzer alone. For the smaller peaks, however, sufficient resolving power can not be obtained by the samearrangement because the ions produced in the region between the electrodes Band C are added to the ionsproduced in the region between the electrodes Band E. Small peaks will be buried under the neighbouring
larger peaks. Use of electrostatic analyzer in conjunction with the magnetic field is necessary for this type of theion spectrum analysis. Double focussing mass spectrometer as shown in Fig. 4 was designed for the detectionof the ions extracted from this source. As the instrument has not only magnetic analyzer but also electric
analyzer, it is expensive and more complex than a single focussing machine, but has an advantage that it cananalyze ions having distribution in energy and in charge states at a time. Its specifications are shown in Table 1.

153

N -3.

ECR Ion Source

M. Yanokura and M. Odera

An electron cyclotron resonance (ECR) type ion source for RIKEN Linac has been
constructed 1) and tested using Ar gas. The layout of the ECR test stand was already reported. 2)
In Fig. 1, we show its photograph.
In this ion source, a 2.45 GHz magnetron is used as the UHF power source. Resonant
magnetic field is about 880 gauss for this frequency. Sufficient magnetic field can be obtainedby use of a pair of solenoid coil. The coil is made of hollow copper conductor and its electricalresistance is 25 mn. The mirror ratio of the magnetic field is determined by the distance between
the coils. In our source, the ratio is 1.8.

1500

20

Fig. 1.

Photograph of ECR ion source

test stand.

Fig. 2.

30
Post! ion ( e m )~o50

Axial magnetic field of ECR

cavity at main coil current of 190 A.

The UHF power is supplied to the ECR cavity through isolator, power monitor, EH tuner
and RF window. Glass ceramic called M1a cor is used as material of RF window. In order toextract an ion beam, only the ECR cavity is kept at a positive high voltage. The othercomponents such as pumps, solenoid coils and their power supplies are kept at ground potential.
Power consumption of the coils is saved by use of a soft iron return yoke.1) When the coil current
is 190 A (42000 AT), sufficient magnetic field is formed as shown in Fig. 2. At this condition,
strength of the magnetic field at the center of the cavity is smaller than the resonance field.
This test stand has three diffusion pumps, and its total pumping speed is 3600 f /sec. WhenAr gas is introduced into the cavity at a flow rate of 0.1 sccm, the pressure inside the cavity isaround 10-4 Torr. After Ar gas was supplied, UHF power is fed into the cavity, and plasma isformed easily at the same time. It is observed by the microwave power monitor that the greaterpart of the power supplied from the magnetron is fed into the cavity.
Extracted beam current increased with increase of extracting voltage. This relation is shownin Fig. 3. In the following test, the extracting voltage was fixed at 7.5 kV. An extracted beam
was analyzed using a bending magnet with maximum B of 108 kgauss-cm, and the ion current

154

-5

10

10

-6

,',

.

j ..... -- ..

,.----.-.

"'-.

2.

<.:

-

~1O

-7

~
u

E

£ 10-8

..

,

-9

10

:~"

A

.~

;\

\6.
\

o

5
10
Extraction Voltage ( kV)

Fig. 3.
Extracted beam current vs.
extraction voltage. Pressure of thecavity is 2 X 10-4 Torr and UHF poweris about 1.3 kW.

o

5. " ' ""'_____...
"~

.

.2
4
.6
.8
Ar gas f low rate ( seem )Fig. 4.
Extracted beam current ofeach charge state vs. Ar gas flow rate.
Ar 5+ ion current includes 0 2+ ion current.
Extraction voltage is 7.5 kV.

was measured by a Faraday-cup. The ion current of each charge state vs Ar gas flow rate isshown in Fig. 4. Ar5+ ion current, shown in the figure, includes that of 0 2+ ions, possibly. Whenthe gas flow rate decreases, Arl+ ion current decreases, and for the gas flow rate larger than 0.4
sccm, its ion current is nearly constant. For the ions of the other charge states, a maximum ion
current is obtained when Ar gas flow rate is around 0.1 sccm.
In this experiment, multiply charged ion current was very small; for example, Ar6+ ion
current was only 1 nA. Therefore we are trying to get more beam current by modification of
the extracting geometry, the microwave window and gas injection nozzle. Furthermore, we
intend to use the permanent magnets for forming multipole field to stabilize plasma and toprevent heating the cavity by plasma.

References
1)
2)

M. Yanokura and M. Odera: IPCR Cyclotron Progr. Rep., 14, 113 (1980).
M. Yanokura and M. Odera: RIKEN Accel. Progr. Rep., 15, 136 (1981).

155

N '-4.

Identification Method of Ions in the
Beam from the RILAC Injector

M. Kase and T. Kambara

The RILAC can accept a variety of ions, from proton to uranium ions, with a mass-to-charge
ratio, M/q, smaller than 24. When multiply-charged heavy ions are produced with the PIG
source,1),2) the M/q spectra of ions at the source are sometimes so complex that it is troublesome
to search for the desired ions. There are, in the spectra, some peaks of comtaminating ions such
as 0+, 0 2+, N+, N 2+, H2 0+, OH+ etc. and also peaks due to the supporting gas when the metal ion
source 3) is used. Moreover, a heavy element has, in general, several isotopes, and there are also
peaks due to charge transfers of ions with the residual gas in the beam duct in the acceleration
stages. To prevent the acceleration of unwanted ions, it is necessary to identify the ions in the
beam from the source, occasionally.
For this purpose, a procedure to know the charge state of ions by use of charge transfer inthe RILAC injection system has been developed. In Fig. 1 is shown the beam line from thesource to the first cavity. The beam from the injector, which is roughly analysed with an ion
source magnet, is bent twice by an angle of 60° with a couple of dipole magnets (BM 1 and BM2).
The procedure to know the charge state of ions is as follows: First, every parameters of theequipments in the injector system are set according to the acceleration conditions and the beamis optimized at the Faraday cup (FC-014) by further tuning. Next, the pressure in the beam
Cavity ~l -1m~

Acceleration tube- { I , I.-

r----~____ial~-------- { SLBS-- HOI
Injector terminal
Ion sourcenFig. 1.
The beam line from the ion
source to the first cavity in the RILAC.
Notations are as follows: FC, Faraday
cup; BM, bending magnet; EM, emittancemonitor; BS, beam stopper; PF, profile
monitor; DQ, doublet quadruple magnet; TQ,
triplet quadrupole magnet; SL, slits.

156

BM2 SCA N 82/ 11/23

10- 4

'"

4: 10

::s

1

10- 6

4:

i

0

=:l

E
m

+

+

~
U

i

10- 7

9

I

40.0

i

::;

1

1

10- 8

~-

~

0

Q)

+

;;;

+

OJ

10- .
30 0

10 N=A R

0
+

10- 5

~

20 :46:38

~

1

j
50 .0

60. 0

70.0

800

90. 0 1000 110.0 120.0

BM 2 ( A)

Fig. 2.

The beam current at FC-O 13 vs.

the BM2 magnet current which has
approximately a linear relation to the magnetic
field in the range in concern. 10 ( = 67 A) isthe magnet current when the beam is optimized.
The peak at 84 A (= (5/4)10) is due to theone electron capture of Ar5+, the peak at
112 A (= (5 / 3)10) due to the two electron
capture of Ar 5 + , and the peak at 44 A(= (2/3)10) due to the one electron lossof 0 2+.
duct between BM 1 and BM2 is raised up from the normal value ("-' 2 X 10- 7 Torr) to several 10- 6
Torr. Then, the beam current at the Faraday cup (FC-O 13) is monitored, as the field in BM2
is scanned. A current spectrum thus obtained for Ar5+ beam is shown in Fig. 2. The spectrum
shows some peaks due to the charge transfer collisions of ions in the beam with the gas in the
beam duct between BM 1 and BM2. Since the momentum of the ions changes very little throughthe charge transfer, the magnetic rigidity of ions is inversely proportional to thier charges. If thecharge number before and after the collision are represented by "i" and "f', respectively, thefield in BM2 which provides a current peak at FC-O 13 for the f-component is given by(i/OB o ' where Bo is the field when the beam is optimized. In the velocity range of the RILAC

injector (0.006 < V /C < 0.016), electron loss processes occur mainly for low i.

On the other hand,for higher i, electron capture processes occur more frequently. As shown in Fig. 2, there are
peaks due to charge exchange processes (i -+ 0 such as (5 -+ 4), (5 -+ 3), and (2 -+ 3). The
spectrum shows that the beam consists of two kinds of ions, Ar5+ and 0 2+. One can also estimate
the fraction of Ar5+ in the beam if the electron capture cross section and the target thickness
are given.
Molecular ions such as H 20+ can be identified by use of a dissociation process like H 20+ -+OH+ + H. In this case, the field which gives a peak for the dissociative component (OH+) is
given by (m f /mi)1/2 Bo' where m i is the mass of the molecular ion and m f the mass of the
dissociated fragment with the same charge state as the incident ion.
These ion identification methods are very simple but reliable. All parameters of magnetic
devices can be fixed after the beam optimization except for BM2 which is less important as the157beam analyser than BM 1 which selects practically the ions to be accelerated by the linac.

References
1) Y. Miyazawa, M. Yanokura, M. Hemmi, F. Yoshida, M. Kase, and M. Odera: IP~R Cyclotron
Progr. Rep., 11, 151 (1979).
2) M. Kase and Y. Miyazawa: ibid., 14, 132 (1980).
3) M. Kase, Y. Miyazawa, and T. Chiba: RIKEN Accel. Progr. Rep., 15, 133 (1981).

158

N -5.

Bunch Signal Sensitization by Use of
Secondary Electron Emission

M. KaseWhen a beam bunch is monitored at the early acceleration stage of heavy ion linacs where
the beam velocity is relatively small ({3 """ 0.01), a bunch signal induced by the slow beam hasa slow response to the bunch shape. Therefore it is difficult to know accurately the longitudinal
distribution of charges in a bunch from the signal shape. In order to eliminate this signal
distortion, a shield plate with small apertures is placed just in front of the detection plate in thecase of a coaxial Faraday cup (Ref. 1). But the plate stops a part of beam and the bunch signals
are weakened . As the result, the measurement should be made with a bad SN ratio. Thisdifficulty can be reduced easily using the secondary electron effect which is usually suppressedin the coaxial Faraday cup scheme.
A secondary electron effect bunch probe was developed and is being used to monitor thebunch structure at the RILAC (RIKEN linac). A schematic diagram of the probe head is shownin Fig. 1. The probe is plunged into the beam line remotely with a pneumatic cylinder during
the measurement. The structure is similar to that of the coaxial Faraday cup except that anelectron collector is set to absorb efficiently the electrons emitted from the stopping plate by theion bombardment.

ShieldBe a ~

BNC
Stopping
pia teElectron
col le ctor

oI

1

2

3

4

Scm
I

Fig. 1.

Schematic view ofthe secondary electron effectbunch probe.

Two kinds of currents appear in the signal coaxial cable. One is the current (Ii) induced by
the ions which approach the stopping plate and collide with it. The other is the current (Ie) due
to the secondary electrons which are emitted from the stopping plate and absorbed by the electron
collector. The signal shapes of these currents were calculated on the assumption that the beam
bunch has a triangular shape distribution with the spread of 2 nsec(fwhm) as shown in Fig. 2 bydashed lines, and that no electric charge is induced on the stopping plate until the ion goes
through the entrance aperture of the electron collector. The results of calculation are shown in
Fig. 2(a) and (b) by solid lines. The signal of Ii occurs before the bunch reaches the stopping
plate and its shape is broadened. The signal of Ie is delayed a little bit but its shape is similar to159

the bunch shape. When the electron collector is biased at a negative voltage as in normal use ofa coaxial Faraday cup, only Ii can be observed since Ie is suppressed. On the other hand, whenthe electron collector is biased at a positive voltage, the signal of Ii + Ie is obtained. But Ie is,in general, much larger than Ii' i.e. ~ >> I, and therefore, the signal shape is given almost entirely
by Ie' The output signals on a 350 MHz oscilloscope are shown in Fig. 3(a) and (b): (a) is witha negative bias on the electron collector, while (b) is with a positive bias. The signals have thesame tendency as those of the calculations in Fig. 2(a) and (b). The factor of signal enhancement,~, which depends on the beam energy, the ion species and the material of stopping plate, isaround 15 for a 2.3 MeV Ar4+ beam with a copper plate for the stopping plate.
Using the secondary electron effect bunch probe, the beam bunch measurement for a low
intensity beam can be made with a better. SN ratio as well as an accurate response to the beam
bunch.

(a )

40

Time

( nsec )

40 «

(b )

::t

Time

Fig. 2.

( n sec)

Calculation of bunch signals. A

solid line in (a) is for Ii and that in (b) is forI e when (3 = 0.015 and the beam current is 1 J.LA.
The bunch shape is assumed as shown by dashedlines. The peak of the bunch reaches the
stopping plate at t = O. ~ is the factor of signal
enhancement by secondary electrons.

Fig. 3.
Bunch signals for Ii (a), for Ii + Ie (b).
The beam is of 2.3 MeV N+ ({3 = 0.019). The
electron collector is biased at - 500 V in (a),+1.5 kV in (b). The trigger conditions of
the both cases are the same.

Reference
1)

1. Klabunde, V. Schaa, E. Schaffner, P. Strehl, H. Vilhjalmsson, and D. Wilms: Proc. of

1979 Linear Acc. Conf., p. 297.

160

N -6.

Bunch Phase Monitor

I. Yokoyama, M. Kase, S. Kohara, and Y. Yano

To know the beam phase relative to rf voltage is very helpful for the fine tuning of rf
accelerators such as the RILAe and the RIKEN sse (under construction). Sometimes, however,bunch signals have bad SN ratios when the beam currents are weak (during the tuning process, forexample) or when the measurements with probes set inside the sse are made in the presence of
seVere rf noises. It is necessary to develop a device which makes it possible to measure the beamphase under such bad conditions and is suitable for use in the variable-frequency scheme.
A bunch phase monitor using the mixing (heterodyne) scheme has been developed. The basic
principle is the same as that in Ref. I: the information on the beam phase is transfered to thesignal with a fixed intermediate frequency, fif This system involves an automatic tuning circuit
for the frequency range of 17 '" 45 MHz . No additional adjustment is necessary when theacceleration frequency is changed.
A block diagram of this system is shown in Fig. I . Two kinds of signals (one is a reference
signal from an rf cavity and the other is a bunch signal from a probe) are fed to the two inputs,
respectively. The reference signal, after its frequency is doubled (f ~ 2f) , is mixed with theoutput signal of a voltage controlled oscillator (yeO) in a double balanced mixer (MIX I). Being
filtered (QF 1), the mixer output is sent back to the phase lock loop. When the circuit is in tune,
the yeO generates the signal of 2f + fif and, as the result, the reference signal in the intermediatefrequency stage is phase-locked with regard to the oscillator (OS I) output. Being filtered again by.-.-.-.---0 As inq;
AMPS

Refere nce
signalcos 21[ f t
!\II

\Tv

~~--Q

Acos q;

AMP8

Bu nchsignalFD : Frequ ency doubler
MI X : Doubl e balanced mixer
QF : Qu artz filte r
SP : Power sp litt er
PD : Phase detec t or

Fig. 1.

VCO : Volt age contr olled osc ill ator
FF : Fi lp - fl op
OS : Osc il lat or
CMP : Compara t or
AS : An alogue swi t ch

A block diagram of the bunch phase monitor.

161

a narrow band filter (QF2), the reference signal is fed to a phase detector (PD2) and also toanother phase detector (PD3) after being phase-shifted by 90° with a coaxial delay line. Whenthe circuit is out of the tunable range of the phase lock loop, it is automatically tuned with theother loop including an oscillator (OS2) by scanning the frequency of the veo output (2fmin +fif ,. . ., 2fmax + fif' where fmin = 17 MHz, fmax = 45 MHz and fif = 10.7 MHz).
The bunch signal, which is generally bipolar, is also mixed with the veo output at MIX2
in the same way as the reference signal. The mixer output is filtered with a couple of narrow
band filters (QF3 and QF4) which remove the effects of frequency components in the bunch
signal other than that of the second harmonics of the fundamental frequency (that is, 2f
component). The bunch signal in the intermediate frequency stage is fed to the other inputs ofthe phase detectors PD2 and PD3.
The two dc outputs are obtained: one is Asin 1> and the other is Acos 1>, where A is a factor
related to the beam intensity. If e is the beam phase to be obtained, then (j = 1/2 ¢ + e, where
e is a constant inherent in the system.

Reference
1)

W. Brautigam, M. Herschbach, K. Kennepohl, and J. Reich: IEEE Trans. on Nucl. Sci.,
NS-26, 2375 (1979).

162

N -7.

Linae Energy Tuning by Phase Control

M. Kase, T. Kambara, T. Tonuma, and M. Odera

The RILAC (RIKEN linac) is a heavy-ion linac with six tunable cavities. To meet the requestof applications for different energies, the beam energy can be varied by changing the following
factors:(1) the number of the cavities in use (from 1 to 6);(2) the acceleration frequency (17 ,. . ., 45 MHz);(3) the input phase of beam bunch to the last cavity.
The first scheme is very simple and normally used in multi-tank linacs. It provides six discreteenergies for a given acceleration frequency. When the second scheme is used together with thefirst one, the energy can be continuously changed over a wide range (0.01 ,. . ., 4.1 MeV In).
However, to operate the linac with the change of the frequency, most of the parameters of thelinac including its injector have to be readjusted and it takes much time to do this. For thefrequent change of energy by fine steps, the third scheme (that is, the phase control) is more
useful than the above, and by combining it with the first scheme the energy can be varied overa wide range.
The method of the phase control is shown in Fig. 1. Let #N denote the cavity used for thecontrol. Turning off the later cavities, '#(N + 1), #(N + 2) .... , and keeping the former cavities,#(N - 1), #(N - 2) ..... in the normal operation, the input phase of the beam relative to the radio
frequency at the first acceleration gap of the cavity #N is shifted from the normal phase (_25°).
Figure 2 shows the variation of energy with the change of the input beam phase, ¢. The solidlines in the figure show the results of the calculation (for N = 3,4, 5, and 6) which were made using
the impulse approximation.1) The experimental results are also shown in Fig. 2. The energy wasmeasured with a dipole magnet (SW magnet) placed behind the cavity #6, while the input beamphase was estimated using the phase shift of the rf voltage of the cavity #N from the normal
condition which gives the synchronous beam phase of -25°. Fairly good agreement between thecalculations and the measurements is obtained.
Beam# ( N-2 ) # ( N- l )B 0Normal ope rat io n

I#N

# ( N+l)

~

00

I

Phase
control# ( N+ 2)

I Turn i ng 0 f f

Fig. 1.

The phase control
method for multi-cavity linacs.

Using the phase control scheme, the output beam energy of the cavity in concern can be
decreased smoothly down to the level lower than that of the input one. It implies that the useof the phase control together with the first scheme provides the continuous energy change in thewide range without varying the frequency. In the range of ¢ between -180° and 0°, noremarkable growth of beam emittance was observed. The energy spread of the output beam has
a minimum value (0.7 % fwhm) at ¢ = 0 and increases gradually as ¢ decreases, being around 2 %

163

N=6

N= 5

___ Los.N......::'----'

N= 41......::z '----'"'* <D

kl cJ·

N=3
20

10
o~

__~__~~+-~__~__~~~

-180

0

180

CPs

(-2 5

0
)

Input phase cP (deg ree)Fig. 2.
The variations of beamenergy vs. the input beam phaseof the "last" cavity (#N) of
those being in use. Energy isnormalized to the designed value
at the cavity #6, E#lf, -25°)= 0.00202 X f2 (MeV In) where fis the frequency in MHz.
Triangles, squares and circles
are the experimental values
obtained at f = 22.3 MHz
for N = 3, 4, and 5, respectively.

(fwhm) at 1> = -120°. The procedure to change the energy in this way is much simpler thanthose including the change of acceleration frequency, because the operator has to adjust no
parameters in the portion from the injector to the cavity #(N - 1), but only the rf phase of the"last" cavity (#N) and parameters of magnetic devices in the later portion of the linac.
In this mode of operation, it is possible that the acceleration frequency is chosen,
independently of the energy in concern, only by taking account of the Mlq value of ions to beaccelerated. In any case, there is no need of the exact frequency setting for each energy.

Reference
1)

T. Tonuma, F. Yoshida, and M. Odera: Reports I.P.C.R., (in Japanese), i1, 53 (1975).

164

N -8.

Suppression of Secondary Electron from Beam Stopper

M. Hemmi

Many slit boxes are used in the beam handling and transport system.1) Each box contains abeam stopper plate downstream to the four slit blades. It is made of copper, cooled by water andis thrown in and out by use of an air cylinder. A large rate of emission of the secondary electrons
is inevitable by bombardment with heavy-ion beams and current reading is enhanced by a factor
of between two and ten for a simple planar stopper plate. The phenomenon makes beamdiagnosis difficult.
Usually, a Faraday cup having a large depth compared to its aperture is used to minimize thesecondary electron effect. However there is no space to accept such a long cup in the slit box.
Therefore, in the initial phase of test operation of the linac, we used method of self-biasing of
stopper by zener diodes. The scheme was simple and seemed to work well. It was, however,soon found that the positive potential developed by self-biasing gives rise to collection of nearby
electrons in the box leading to the current reading lower than that of the correct value. We haveatopted another method. A shallow cup is fixed on the stopper plate and a pair of rare-earth
cobalt magnet forms magnetic field across volume of the Faraday cup composed of the cup andthe plate. Figure 1 is its photograph. The cup is insulated. There is no need of power supply
for electron suppression, and this makes its structure simple and compact. Stronger magnetic
field might be desirable for suppression of the secondary electrons. However the stray field in

Fig. 1.

Photograph of the beam
stopper equipped with secondary electron
suppresser which uses rate-earth cobalt
permanent magnets.

165

the beam path, when the stopper is extracted out of the path, may affect the beam andgive undessirable effect in the beam trajectory downstream when the stray field is too large.
Therefore, assuming almost all the secondary electrons are of energy less than 300 eV we haveconcluded that the field strength of around 100 G is sufficient for electron suppression. By
adjusting the number and relative positions of the permanent magnet pieces, we have succeededin producing necessary field strength and its distribution in the Faraday cup. In Fig. 2 are shown
results of measurement of the leakage field along the straight paths at various distance from thereplaced beam stopper. The curve tagged 0 is measured on the beam axis and 10 corresponds tothe line displaced 10 mm from the axis to the stopper. Integrated field strengths are shown in
the inset of Fig. 2. This field gives only negligible deviation of the beam. Comparision ofcurrent readings by this magnet-equipped shallow cup and by a normal long cup was made withan Ar beam. Any systematic difference between two readings was not found assuring effective
suppression of the secondary electrons by the magnetic field given by the permanent magnets.
We are preparing for further measurements using heavier projectiles.

40

30

(/)

(/)

ii5

(.9

20

O( Beam ax is) : 50 C-em
10mm
: 100 C -em

10
aXIs

o
Z (mm)

15mm: 160(; -em

Fig. 2.
Leakage field distribution
along the beam path. Number on eachcurve means distance in mm of pathfrom the center line of the beam pipe.
Distance of the edge of the stopper fromthe beam axis is 20 mm. Inset gives
integrated field strength.

Reference
1)

M. Hemmi, Y. Miyzawa, M. Odera, and T. Tonuma: IPCR Cyclotron Progr. Rep., u.., 138(1978); M. Kase, I. Yokoyama, and M. Hemmi: ibid., 14 115 (1980).

166

N -9.

Status of RILAC RF System

T. KuboIn this period, several improvements were made in the RILAC radio-frequency(RF) system.!)
The control circuit 2) fabricated temporarily for each main resonator was improved to simplify andstabilize the operation further. This circuit has been used to provide beams since last year.
A similar control circuit was applied to an RF buncher 3) which had been used in the injection
beam line to improve acceleration efficiency.
(1) RF system of six main resonators
Figure 1 schematically shows the present control circuit equipped for the RF system of eachmain resonator.
This control circuit includes four feed back loops as follow:(i) Loop for stabilizing the amplitude of the accelerating voltage generated in the resonator,(ii) Loop for maintaining the tuning of the resonator,(iii) Loop for restoring the accelerating voltage,(iv) Loop for stabilizing the accelerating phase.
The last two loops were newly added to the control circuit described in Ref. 2.
The third loop is designed to restore automatically the accelerating voltage lost by a discharge
which occurred in the resonator. When the voltage is lost by the discharge, it cannot usually berecovered again of itself because multipactoring phenomena rapidly grow in the resonator and its
vacuum becomes worse. To regenerate the voltage, the multipactoring phenomena have to be
extinguished by once turning off the excitation of the resonator. The auto-restoration circuit inthis loop performs this procedure automatically referring to a feed back signal of the accelerating
voltage. The excitation signal is instantly turned off when the voltage is lost, and the excitation
mode is changed from continuous wave(CW) mode to pulse mode(""'1.5 Hz, duty factor ""'5 %).
The small duty factor allows ions and electrons generated by the discharge and the multipactoring

Pi c k- up,--------~

L -_

_

----'-_--I Recti f i er I - -- - l

Res onat orPoweramplifierillCapac iti ve\ tr imme r\

Fig. 1.

\A schematic diagram of the control circuit for the main resonator.

167

phenomena to recombine or drift to the resonator wall during the time between pulse excitations,so that probabilities to fall into the multipactoring decrease. As soon as the voltage is generated
during the pulse mode, the excitation mode is again switched back to the CW mode. Thus thevoltage can be quickly restored, and the CW excitation in such an abnormal state can be avoided
that the final tubel) has a very different load impedance from regular one because of theoccurrence of the multipactoring. When the RF power is continued to be fed in such amismatched state, some troubles are frequently induced.
This loop is also found useful to search a resonance of the resonator. The accelerating
voltage can be generated only when the resonator is almost on the resonance. The resonator is
excited by the pulse mode if it is far off the resonance. Thus the search can be made by moving
a capacitive trimmer manually in such direction that the excitation mode automatically turns
to the CW mode.
The fourth loop can suppress phase noise and phase drift of the accelerating voltage. These
phase errors are detected by a phase detector and are fed back to a phase shifter so that they canbe compensated.
Part of the control circuit is connected to the control computer(HP I 000)4) in the control
room. So far, the generation of the accelerating voltage, the adjustment of the reference signal
for it and the activation of the first two feed back loops are controlled by the computer.
(2) RF system of buncher
A schematic diagram of the RF system for the buncher is shown in Fig. 2. The resonator of
the buncher is of a quarter wave length coaxial type, and its frequency tuning is made by avariable vacuum capacitor (VVC). A wide band amplifier is used to excite the resonator.
The control circuit for the buncher includes two feed back loops to stabilize the amplitude
and phase of the bunching voltage. They consist of a phase error detector, an amplitude error
detector and an amplitude and phase controller.
The feed back loop to maintain the tuning is not included in the circuit because the Q-valueof the resonator is low(1000 "" 1500) and the necessary RF power is small(less than"" 150W). The
feed back loop to restore the bunching voltage is also not included because the multipactoring
phenomena have not occurred as yet.
Operation frequencies used in this period for the beam acceleration are between 18 and 30
MHz.

17-45MH z
Frommas ter osc.

Resonator

Fig. 2.

A schematic diagram of the RF system for the buncher.

168

References
1)
2)
3)
4)

T. Kubo and Y. Chiba: IPCR Cyclotron Progr. Rep., l.±, 123 (1980).
T. Kubo, M. Hemmi, and Y. Chiba: RIKEN Accel. Progr. Rep., 15, 137 (1981).
M. Yanokura and M. Odera: IPCR Cyclotron Progr. Rep., U, 149 (1979).
T. Kambara, M. Odera, and S. Takeda: ibid., p. 134.

169

N -10.

Investigation of Frequency Characteristics of the

Screen Grid

BypassCapacitor at the Final Stageof RF Power Amplifier for RllAC

T. Fujisawa and Y. Chiba

The RIKEN 1ine:ar accelerator (RILAC) has been constructed and operated well in thefrequency range of 17 to 30 MHz. In order to extend the frequency range up to 45 MHz, theperformance of the screen grid bypass capacitor at the final stage of the RF power amplifier wasinvestigated. In Fig. 1 the schematic diagram of the amplifier is shown. The investigation was
carried out as follows: The amplifier was disconnected from the feeder line, and the plate andgrid circuits were tuned in the frequencies to be measured. The plate circuit was excited by asignal generator, and the screen and control grid voltages induced from the plate were measured
with oscilloscopes. In Fig. 2, the schematic view of the bypass capacitor is shown. The screen
grid voltages were measured at position A, B, and C. The plate and control grid voltages were
measured with the voltage pick-ups shown in Fig. 1.
Grid vo ltage
pi ck - up

mrP
j

Elmac

Wi de
band
Amp.
250W

3c; 3000 A 7 ,J;,

pS

.

psI

20 - 200 pF
VVC
RCA4648 2000pF
Feederj ~c,240p F :==:I Plateps

Grid stub

stub

PS

P. S

~

Fig. 1.

Simplified diagramof the RF power amplifier of
RILAC, P.S: Po\ver supply.
Cs : Screen grid bypass
capacitor.

In Fig. 3, the ratios of control and screen grid voltages to the plate voltage are shown(closed circles). The frequency dependence of the ratio is complicated in the range of 33 to
45 MHz, which is not desirable for the stable operation of the amplifier.
This resonance-like frequency dependence is cau,sed by the ceramic capacitors at the outerends of the sheet capacitor using KAPTON film. The subsequent measurements were carried out
without the ceramic capacitors. The results are also shown in Fig. 3 (open circles). The frequency
dependence of the ratio becomes simple except the resonance at 34 MHz. This resonance iscaused by the choke coil in the plate circuit of the preceding amplifier. After the improvementof the choke coil the flat frequency dependences was obtained.
The measured ratios of the screen and control grid voltages to the plate voltage are about
0.006 and 0.08, respectively, in the frequency range of 17 to 45 MHz. Much smaller ratios aredesired for the stable operation of the amplifier. Improvements of the KAPTON sheet capacitor
were carried out. The performance of the improved capacitor is presented by the authors inthis progress report. 1)

170

ScreenbypassScr ee ngrid, /150 fJ. mKAPTON/Pl ate/,E = = 3

Ceram ic capac itor

(1000p F )A- A' Cr oss sec ti onal v iew

0,01

0,001 L-----.J_ _---L-_---l._ _- L - _ - - L_ _..L.-_o

OJ

Position B('\.J

A-+-+-+---I-+---+---+---+-- - - ---+~- A'

300\
125 II m KA P TON f ilm

20

P lane view

Schematic view of theFig. 2.
screen grid bypass capacitor. The
screen voltages are measured at
positions A, B, and C. The
capacitance of the KAPTON sheet
capacitor is 0.03 ~F.

25

40

45

Ratios of the control andFig. 3.
screen grid voltages to the plate voltage.
The lines are only to guide the eye.
The closed and open circles are the datawith and without the ceramic
capacitors, respectively. See the text andFig. 2.

Reference
1)

35

Reso nant fr eq uen cy ( MHz )S. Kohara, T. Fujisawa, and Y. Chiba: p. 171 in this report.

171

N -11.

Basic Study on the RF High Power Amplifier
for RIKEN

sse

Study of the Screen Bypass Capacitor for the Final Stage

S. Kohara, T. Fujisawa, and Y. Chiba

Screen bypass capacitors for RCA 4648 tetrode were manufactured by way of trial, which
will be used for the high power amplifiers of RIKEN SSC. The performance of capacitors wasstudied.
The power amplifier for the resonators of RIKEN SSC is required to supply the maxim:um
RF power of 300 kW in the frequency range of 17 to 45 MHz. RCA 4648 tetrode is to be used
as a grounded cathode amplifier. In Fig. 1, the schematic diagram of the amplifier is shown. The
plate tuning circuit is a "A/4 type stub and tuned by changing the length of the stub. The grid
tuning circuit is a "A type stub and tuned by a variable capacitor. In Fig. 2(a), the simplified
circuit diagram of the amplifier is shown. The symbols Co '" C4 show the capacitances between
electrodes of the tetrode and Cs shows the capacitance of the screen bypass. For the stable
Co upli ng capac it or
di sk

FeederI-~------ - I

I

I
I

I
I

I
I
I
I

I
I

Sc ree n bypass
capaci tor
Tuningcapcitor

Fig. 1.

Gri d dummy
load

I

I

~-------­
Reso nat or

Schematic diagram of the high power amplifier of RIKEN sse.

Capaci t ances given in th e ca talog ue (measured)

Co = 06p F ( 1. 5p F )C2 :S 85pF ( 75pF)
C3 = 775 pF (737pF )C= 425pF (357pF )Cl =( 4.5pF )P : Pl ate
Gl : Control gridG2 : Screen grid
K : CathodeFig. 2(a) Simplified diagram of
the circuit of amplifier.

Fig. 2(b) Equivalent circuit for thecircuit in Fig. 2 (a).

172

operation of the amplifier, it is necessary to reduce the coupling between the plate and control
grid to a value as small as possible. A part of the coupling is due to the direct interelectrodecapacitance Co. The other part is attributed to the screen bypass Cs which takes a finite value.

The latter effect can be replaced equivalently by an additional capacitance Co * to Co as shown in
Fig. 2(b). It can be seen that the capacitance of screen bypass has to be as large as possible inorder to reduce the coupling.
In Fig. 3, the screen bypass capacitor manufactured is shown. The insulator is made of
50 ,urn KAPTON film (prepared by Du Pont). The calculated and measured capacitances are
0.28 ,uF and 0.11 ,uF, respectively. This discrepancy was supposed to be due to poor flatness ofthe electrode of the capacitor. Therefore the KAPTON film coated by conductive silver paintwas examined. The capacitance became 0.26 ,uFo
The 50,um KAPTON film could endure a voltage as high as 5 kV DC for a long time (30h) in a preliminary test.
The capacitor was mounted on RCA 4648 tetrode without the plate and grid tuning circuits.
The plate was excited by a signal generator, and the voltages of screen and control grids induced
from the plate were measured. In Fig. 4, the ratios of screen and control grid voltages to theplate voltage are shown as a function of radiofrequency. The ratios, when the screen grid was
grounded, are also shown. The flat frequency responses seen in Fig. 4, show that these capacitors
operate well in this frequency range. The value of Co deduced from the ratios is 1.5 pF andthose of Co * for Cs = 0.11 ,uF and 0.26 ,uF are 0.5 and 0.2 pF, respectively. The measured
value of Co is 2.5 times the value given in the catalogue. The capacitance Co * for Cs = 0.11 ,uF
is one third of Co. In stability consideration of the amplifier it is indispensable to take acountof the coupling effect of this order of magnitude.

KAP.
50 u mScreenelect\di EaA,iPI~;el

10 - 2

Cross-sectional view

egl

ep

(

C5 = O.l,u F )L•..._:=:=:1:=:=:=:: :::../
if)

o

~

et:::

x_x_x_x_x_x_x_x_x

10- 3

grounded)eg2_ .JJ-ep_ -cr-o-_o-...o--o-...o-,Ly-e x - - " , _ eg

epl(C = 015.,uF)(C 5 =026.
,u F ).1Pl ane viewFig. 3.

eg l (
ep
G2 was..0--0-t:.-_e:.-_..c.--f::r-~-.-L:::.--

668~~l (C5=0.26,u F )The capacitor manufactured.

Frequen cy( MH z)Fig. 4.
Ratios of the screen and control gridvoltages to the plate voltage.

173

Grid Tuning Circuit of A. Type for the RF PowerN -12.

Amplifier for RIKEN SSC

s. Kohara and T. Fujisawa

The amplifier of RIKEN SSC is required to work in the frequency range of 17 to 45 MHz.
An RCA 4648 tetrode is to be used for the final stage of the amplifier. The capacitance of thecontrol grid to the screen grid and cathode is 1200 pF (in the catalogue). The necessary grid RF
voltage is estimated to be 300 V to drive the 4648. The capacitance as a load for this voltage at
the highest frequency drains a large current which is difficult to be supplied directly by any
reasonably sized amplifier. Therefore it is desirable to drive with a grid tuning circuit. A A typegrid tuning circuit is designed which is tuned by a variable capacitor. Figure 1 shows theschematic diagram of the circuit. The capacitance (C in ) is determined to equal the grid
capacitance (1200 pF). In Fig. 2, the capacitance of the variable capacitor required to tune thecircuit is shown as a function of radio frequency. This circuit has following merits:(1) The grid voltage is equivalent to the input voltage.
(2) The tuning and impedance matching are simultaneously done by one variable capacitor.
Frequency dependence of grid input impedance of the 4648 is studied in order to design thetuning circuit in detail. In Fig. 3, the simplified circuit of the 4648 is shown. The symbols Co
to C4 are the interelectrode capacitances and Cs is the capacitance of the screen bypass. The grid
input impedances are measured in the frequency range of I to 80 MHz using the device shownin Fig. 4. In Fig. 5, the results are shown together with the calculated impedances. The
impedances calculated with the interelectrode capacitances (broken line) are not in agreement with

~

0..

10 3
Cf)
Q)

u

c
ro
.......
u

ro
0..
ro

L
0.7m )
0.8m)
0.9m )
l.Om)

u

10

'I

Var iable
capac ito rl2

Scr een by passca pacit or

Gr id
du mmy l oad

Fig. 1.
Grid tuning circuit of theamplifier which uses an RCA 4648
tetrode.

Frequency( MHz )

Fig. 2.
Capacitances of the variable capacitor
for tuning the grid circuit. The parameters
are the length of the coaxial line. See Fig. 1.

174

the measured impedances in the frequency range of 30 to 80 MHz. The circuit of 4648 cannot
be represented by the calculation with only direct interelectrode capacitances in this frequency
range .
Capacitances in th e ca t alog ue

Co = 06p F C3 = 775pF
C2 ~85p F C4 =42 5pF
p: Plate
GI: Control gridG2 : Sc ree n grid
K : Cathod e

Ui
Q)
<.)

c

CD
-0
Q)

rr

Fig. 3.
Simplified circuit diagramof the 4648 tetrode and screen
bypass capacitor.

E

Frequency(M Hz)

Fig. 5.
Frequency characteristics ofthe grid input impedance of RCA 4648
tetrode. The open circles show themeasured data. The solid, broken anddotted lines show the impedances
calculated for the circuits in Figs. 7, 3,
Cross sectional viewFig. 4.
of the device for measurementof the control grid impedance.

CI

600 ( pF )C2 : 450 (p F)
:

L2

Cl

I
L :
L2 :

4
6

(n H)
(nH)

LI

G I ~ ~G2

o

C2

T

and 6, respectively.

Screen bypass
capac itor

T

z-

153

I

Z,,, =15(J--f }!1050 pF

K

Fig. 6.
Equivalent circuit of thegrid of RCA 4648 tetrode given by
Yingst et al. with screen bypass
capacitor.

CircuH constructed with
Fig. 7.
transmission line and capacitor, of
which impedances are equivalent to
the grid input impedances of RCA
4648 tetrode.

175

In Fig. 6, the equivalent circuit of the 4648 given by Yingst et al.l) is shown. The grid input
impedances calculated for this circuit (dotted line) are also shown in Fig. 5. The measured
impedances are well reproduced by the calculation. Therefore the capacitance (1200 pF) at the
input of the tuning circuit has to be replaced by the equivalent circuit. The equivalent circuit
can be approximately transformed to a circuit which consists of a transmission line and acapacitor (see Fig. 7). The impedances calculated for this circuit are also shown in Fig. 5. The
impedances calculated for these circuits agree with each other. If the 'circuit shown in Fig. 7 isinstalled at the input of the tuning circuit and the circuit is tuned, the input impedance becomesequal to the resistance of the grid dummy load.

Reference
1)

T.E. Yingst, D.R. Carter, 1.A. Eshleman, and 1.M. Pawlikowski: Proc. of the IEEE, Mar.
p.357 (1973).

176

N -13.

Control System of the Lince

T. Kambara, M. Kase, and T. Kubo

The control system of the linac with an HP-lOOO computer system!) has been working
stably since November 1979. Major troubles of the computer system occurred three times during
the period from October 1981 to October 1982: one was due to the failure of the memory
controller and the others were due to the parity error of the memory. The time spent for therecovery was one day for the former case and a few hours for the latter cases which caused little
trouble on the linac operation.
The communication line between the computer and devices in the accelerator vault was
replaced from a serial data link with a twisted pair cable to HP-IB extenders (HP 37203A)
with optical fibers. It increased the data transfer rate from 180 characters/sec to 40 kbyte/sec
and allowed quicker response from those devices to operators' commands. The serial link is now
available as a back-up communication line in case of break-down of the optical fiber systems. It
can also be used for a portable terminal (HP-3070A) with a keyboard to communicate withthe computer from places in the accelerator vault.
An HP-IB interface card was added to the computer system, resulting in two cards. The
communication with nearby devices connected by HP-IB cables and that with distant devices
connected by the optical fiber systems were separated among the two interfaces.
The auto-tuning circuits of the radio-frequency system 2) were connected to the computer.
Thus the amplitude of the acceleration voltage in the cavities is controlled and monitored at
the CRT terminals on the control console. The RF signals of the cavities and the beam bunch
signals which are picked up between the cavities are sent to the control room with dedicatedcoaxial cables and are displayed on an oscilloscope. Therefore the adjustment of the RF phasehas become much easier. These improvements contributed to the speed-up of the tuning of the
RF system.
The vacuum pressure values measured at the beam injection line, the cavities and the beamswitching magnet are monitored in the control room at both the control console and a monitoring
panel for the vacuum system. The meters on the monitoring panel were replaced by a l2-point
dot printing recorder to take continuous long-term records. At the same time, the values of thevacuum pressure at the cavities are sent to the computer to give information on the condition of
the RF system. The parameters of the PIG ion source are also sent to the computer for themonitoring and recording.
The values of the magnet currents can be recorded on a magnetic tape at any time during thelinac operation. The recorded data are used to reproduce the past setting at the start-up of thelinac and also used for later analysis of the parameters.
A block diagram of the control system in October 1982 is shown in Fig. 1.
We intend to improve the display and key-in systems on the control console by introducing
new devices like a color graphic CRT display and a touch panel. We also intend to gather, process
and display the data from beam diagnostic devices by the computer.

177

Op erato r co nso le

CPU : HP 2113B
Memo ry
16 bit x 96kw 1 - - - - - - - - - 4

MTA block diagram
Fig. 1.
of the control system in

Inj ection
Li ne

RF :j:I: 1~3

RF :j:I:4~6

Bea m Tr ansport
SystemOctober 1982. 2240A
denotes a measurement andcontrol processor, 37203A
denotes a HP-IB extenderby optical fibers , and 3070A
denotes a local terminal
connected to the serial data
link.

References
1)

T. Kambara, S. Takeda, and M. Odera: IPCR Cyclotron Progr. Rep. , 14, 110 (1980).

2)

T. Kubo, M. Hemmi, and Y. Chiba: RIKEN Acce1. Progr. Rep. , 12., 137 (1981).

178

N -14.

On a Possible Medium -/3 RFQ Structure

M. Odera, T. Chiba, and M. Hemmi

The RFQ, or radiofrequency quadrupole structure of linac has been devised to provide
transversal focusing force as w~ll as accelerating field at a time by controlling the radiofrequency
field. The scheme was originally proposed by V. V. Vladimirsky.1) Initial trial to apply theprinciple for a heavy-ion accelerator was not successful,2) and received little attention until it wasrediscovered at LANL in summer of 1978 in a Russian paper written by I.M. Kapchinsky and
V.A. Teplyakov. 3) D.A. Swenson and his accelerator division, AT -DO of LANL, achieved rapid
progress in formulation of the method of analysis of the orbit and made the detailed model study,
culminating in realization of the acceleration of protons up to 640 keY in early spring 1980. 4)
The very attractive characteristics of the RFQ demonstrated are large capture efficiency of injectedbeam to the acceleration regime and a very low voltage required for injection. Efficiency of morethan 90 % has been reported. The high efficiency is useful for acceleration of heavy ions sinceyield of the multiply charged ions from ion source is far from being copious. Also the small
beam spill will make problem of activation less for deuteron acceleration than the usual linac
schemes. Injector voltage around 30 to 50 kV is enough for proton allowing ellimination of theexpensive and voluminous high voltage equipments.

Fig. 1.

Sketch showing a general idea of a medium-~

Alvarez-type RFQ structure.
Although feasibility of acceleration of very heavy ions by this scheme remains still to be
demonstrated, INS, University of Tokyo, has succeeded in operation of an RFQ for Li
acceleration,S) showing validity of principle of the structure. However, it is also believed to beeffective only in the low-~ region of less than a few %. The structures developed in the UnitedStates or Germany lose power efficiency rapidly with increase of particle energy. We have tried
to find other structures effective in the higher energy region. Figure 1 shows one such structure
examined. It resembles the "drift tube structure with horn" studied by Boussard. 2) Unlike thepredecessor, ours has no metalic cylinder to protect ions from deceleration field. It is composedof horizontal and vertical pairs of rods supported by separate stems. Axial distance between
stems for the different pairs is ~A and between neighboring stems of the rods in the sameazimuthal position is 2{3A. Accelerating field exists around the gaps of the rods and its period is{3A, since the gaps of different pairs alternate with each other.
In order to investigate this structure, a high frequency model and a magnetic analogue model
have been fabricated as shown in Fig. 2 and Fig. 3. The high frequency model has two cells
and is being used to study effect of capacitive loading of the resonator by the quadrupolar rod

179

Fig. 2.
Photograph of the two-cellhigh frequency model.

Photograph of the magnetic
Fig. 3.
analogue of the center region of the RFQ
for study of the three dimensional field
pattern.

configuration. Its resonant frequency was found to be 351.98 MHz and its cell length of 48.9mm corresponds to (3 = 5.7 %, or roughly 1.5 MeV In which can be expected for particles
accelerated by our heavy ion linac, RILAC or a 10w-{3 RFQ structure. The magnetic analogue
model made of iron is used to measure the three dimensional field distribution in thisconfiguration. Near the beam axis, the pattern of the magnetic field closely reproduce that ofelectric field, if penneability of the iron is sufficiently large. Result of measurement of axial field
is shown in Fig. 4. Considerable axial component exists even in the midway of distance between
the accelerating gaps. This field pattern makes transit time factor less than 0.5. The numericalvalue may be improved somewhat by adjusting rod size and aperture. However, such an open
electrode structure seems not suited for getting a good acceleration efficiency. We are investigatingother characteristics of this structure and trying to find better RFQ configuration suitable to be
used in the medium-{3 region.

260
240
220
<U
200
x
<U
180
0 160
:5 140
c 120
100
80
>
60
<U
40
0:::
20
0
::s2
<J)

~

<J)

(f)

<J)

<J)

Fig. 4.

Distribution of accelerating

60 field measured along the axis of the
Position of probe ( mm )magnetic analogue model.

180

References

1)
2)
3)
4)

V. V. Vladimirsky: Pribory i Tekhn. Eksp., 1, 35 (1956).
D. Boussard: IEEE, NS-12, 640 (1965); Compo Rend. Ac. Sci., 265, 4665 (1965).
I. M. Kapchinsky and V. A. Teplyakov: Pribory i Tekhn. Eksp., U, 19 (1970).
R. W. Hamm , K. R. Crandall, L. D. Hansborough, J. M. Potter, G. W. Rodentz, P. H. Stokes,
1. E. Stovall, D. A. Swenson, T. P. Wangler, C. W. Fuller, M. D. Macha1ek, R. A. Jameson,

5)

E. A. Knapp, and S. W. Williams: Proc. Intern. Conf. on Low Energy Ion Beams, Bath,England, Apr. 1980; T. P. Wangler and R. H. Stokes: IEEE, NS-28, 1494 (1981).
Y. Hirao: Private communication.

181

N -15.

Present Status of the RIKEN

sse Project
H. Kamitsubo

The RIKEN Separated Sector Cyclotron (SSC) Project started in 1980. It aims at construction of a K = 540
SSC for the purpose to extend research activities in nuclear science at the Institute of Physical and Chemical
Research. The SSC will be a post accelerator of the present variable-frequency heavy-ion linac (RILAC). In
addition to the RILAC, an AVF cyclotron will be constructed at the final stage of the project as the second
injector for the SSC. 1)
The sector magnets with trim coils and their power supplies were ordered to Sumitomo Heavy Industries
Ltd. in 1981 and construction of them is now under way. Two among four sector magnets were completed in
June, 1982. After installing them at the factory, excitation characteristics and field distributions were measured.
In order to measure the field distributions correctly in the valley region between two sector magnets, alignment of
two magnets was carefully done so that their median planes exactly coincided with each other and the center radiiof the poles made a right angle to each other. Figure 1 shows a photograph of two sector magnets installed at
the factory.

Fig. I.
Photograph of two sector magnets
installed at the factory of Sumitomo Heavy
Industries, Ltd.
The field measuring device was designed by us and was made by Sumitomo Heavy Industries, too. It is
made of aluminum and can be equipped with twenty Hall elements. The holder of the Hall elements can be moved
radially as well as azimuthally by a driving system with air pistons. 2)
Results of the measurements were quite satisfactory.3) Very good agreement was obtained between the
results of the measurements and the calculations with TRIM code on the excitation characteristics of the magnets.
The magnetic field of 1.55 T, which is the maximum base-field strength required for operation at the highest
magnetic rigidity, was achieved with a magnetomotive force of 1.28 X 105 AT. Distributions of the base field in
the valley and hill (gap) regions were measured at the field strength of 0.7, 1.1, 1.5, and 1.57 T. Effective fieldboundaries and effective sector angles were determined from the measured field distributions as a function ofradial coordinate, R. Variation of the effective sector angles with R is small except in the region of small R.
Distributions of the field produced by the trim coils were also measured along -the center radius of thepole. Method of the optimization of the trim coil currents were developed. 4) Orbit calculations were made bytaking the actual field distributions into account.
Conceptual design of the RF system has been performed. Two types of the resonator cavities were
investigated from eIectrical and mechanical points of view and finally the resonator having a movable box asa frequency-changing device was adopted,S) since total height of the system and the current density at the contact

182

fingers can be reduced considerably as compared with that hav.ing a moving short. The one-fifth scale modell
resonator was made and the resonant frequency, Q-values and radial distributions of RF electric field were measured
for it. Results of the measurements were very satisfactoryS) and a larger scale model will be made to get more
precise data.
The vacuum chamber of the SSC is divided into eight sections, that is, four magnet chambers, two RF
resonator chambers and two valley chambers. The reason is that the RF resonators should be withdrawn backwards
for adjustment and repair. Because of limited space in the central region of the SSC, it seems to be impossible
to apply usual vacuum sealing method. A sealing method with pneumatic expansion seals is considered to' save
space and to simplify connecting and disconnecting procedure of the RF resonators.
Three different types of one-third model of the seal were made and tested to investigate their performance. 6)
Numerical analysis of the elastic and plastic deformation of the seal using the finite element method is now inprogress. Design of the evacuation system has been performed. Total 'pumping speed of 16 X 104 £/sec isneeded to keep the vacuum in the chamber better than 1 X 10-7 Torr. Cryogenic pumps as well as turbomolecularpump~ will be used.

In order to save time for pumping possibility to apply the discharge cleaning technique has

7been investigated. )Beam from the injectors is to be injected along a line tilted to the median plane of the SSC. 1) Design of thebeam transport line between the RILAC and the SSC and the section for beam matching to the acceptance of the
SSC was almost finished. Detailed design of the injection elements such as bending magnets, magnetic inflection
channels and electric inflection channel and also the extraction elements is in progress.
Conceptual design of the controle system has been continued. It consists of a network of several
minicomputors and CAMAC system. To decrease the number of CAMAC crates and signal cables, new CAMAC
modules named CIM (Communication Interface Module) and DIM (Device Interface Module) are being developed.
They have microprocessors inside them and are connected to CAMAC data-way. Sixteen DIMs will be connected .
to one CIM through serial lines of optical fibre cables. The CIM has a random access memory to store the data
sent from the DIMs at a proper time interval.
We have a plan to optimize the operation of the SSC by using the computer. In order to realize thissuccessfully it is necessary to equip various types of beam diagnostic devices for measurement of current distributions, emittance and phases of the beam inside the SSC and also along the beam transport lines. Theoretical
study of adjusting and optimizing procedure is in progress. Detailed design of the beam diagnostic devices is
continued.
The beam transport lines to the experimental areas can be operated in the following modes: (1) Achromatic,
double telescopic transport to every target area, (2) double dispersive, double telescopic transport with momentum
resolution up to 25000 and (3) isochronous, non-dispersive, double telescopic transport. 8} Beam dynamical
calculations were almost finished and final design of each magnet is in progress.
Basic design of the SSC building was finished last year and radiation protection problems were examined.
Construction of the building will start soon.

References
1)
2)
3)
4)
5)
6)
7)
8)

H. Kamitsubo: Proc. of 9th Intern. Conf. on Cyclotrons and their Applications, Caen, p. 13 (1981).
H. Takebe, I. Takeshita, J. Fujita, I. Yokoyama, T. Wada, and S. Motonaga: Proc. 4th Symp. on Accel.
Sci. and Technol., Wako, p. 301 (1982).
S. Motonaga: ibid., p. 293.
A. Goto, H. Takebe, S. Motonaga, and T. Wada: ibid., p. 295.
K. Ogiwara, T. Fujisawa, and Y. Oikawa: ibid., p. 247.
K. Ikegami, S. Nakajima, and Y. Oikawa: ibid., p. 207.
Y. Ishibe, H. Ohyama, Y. Sakamoto, K. Ikegami, S. Nakajima, Y. Oikawa, and S. Motonaga: ibid., p. 221;
K. Ikegami, S. Nakajima, Y. Oikawa, S. Motonaga, Y. Ishibe, H. Ohyama, and Y. Sakamoto,: ibid., p. 223.
T. Inamura, N. Kishida, H. Saito, and M. Watanabe: Sci. Papers I.P.C.R.,li, 236 (1981).

'183

N -16.

Construction of the Sector Magnets for the

RIKEN SSC

S. Motanaga, H. Takebe, A. Gata, T. Wada,
Y. Oikawa, I. Takeshita, Y. Ikegami, J. Abe,*
T.Tsukumo,* H. Saita,* and T. Sata*

Fabrication of the sector magnets started in 1981 at the factory of Sumitomo Heavy Industries. The first andthe second magnets of the four sectors were completed in March and July 1982, respectively. In April we mademeasurement on the basic characteristics of the magnetic fields, machining accuracies of the fabrication and otheroperational properties with one sector magnet excited. Measurement of fields for use in the orbit calculations was
carried out with the two sector magnets. Results of the field measurements are presented elsewhere in this report. 1)
The detailed design study and technical problems on the construction are described in the previous report?)
Table 1 lists the characteristics of the sector magnet. The magnetic field of 15.8 kG was achieved with themagneto-motive force of 1.35 X 105 ampere-turns and the effective angle of sector magnet obtained from themeasurements was found to agree with the designed value of 50° to 51 0. Because the magnetic field strength andfield profile for the sector magnet depend on the quality of its material, very high homogeneously forged androlled steel with low carbon content was used for the poles and yokes. Table 2 tabulates the measured
characteristics of the steel used. The ratio of cross sectional area of the yoke to that of the pole base is 0.94.

Table 1. Characteristics of SSC Magnet.
Number of sector magnets

4

Maximum magnetic field

15.8 kG

Sector angle

50°

Maximum magnetomotive force

1.38XI0 s A-T

Gap width

8cm

Maximum current

1050 A

Height of magnet

5.24m

Maximum power

480kW

Total weight2105 ton

Number of trim coils

29 pairs X 4

Maximum current

590 A

Total trim coil power

21 6 kW(526 ton/one sector)

Table 2. Measured characteristics of the low carbon steel (weight percent).

Pole

Yoke

C

Si

Mn

P

S

Cu

Al

0.01

0.001

0.08

0.013

0.002

0.01

0.018

{ 0.01
0.01

0.001

0.09

0.011

0.003

0.01

0.036

0.001

0.10

0.011

0.01

0.031

0.04

<0.01

0.31

0.14

<0.01

0.30

0.10

{ 0.04* Sumitomo Heavy Industries, Ltd.

0.002

184

Table 3. Operational characteristics of the coils for sector magnet.
Suppliedcurrent(A)Power
consumption(kW)

Temperatureof coilCC)

Temperature
increase of
water(l',°C)

Resistanceof coil

500

26.5

26

7

0.105

700

(n)

52

33

13

0.107

900

88.5

42

21

0.109

1000

112.5

48

27

0.113

1100

138

55

33

0.114

Pressure drop of the cooling water: 5 kg/cm 2
Flow rate of the cooling water: 54 £/minSpecification of the power supplies of coils for SSC Magnets.
Max.
current (A)Max.
Voltage (V)

PS-l

1050

352

PS-2

1050

133

By pass
current (A)

Power
(kW)
370

70

140

Measurement of the fabrication accuracies of the two sector magnets was done by the manufacturer. The
obtained accuracies of their fabrication and assembly are as follows:
Gap distance
Sector angle
Pro me of pole edge
Parallel setting of trim-coil assembly

0.04 mm
0.006 deg
0.13 mm
1 mm

Flatness of pole face0.02 mm

The power consumption in the main coils, the flow rate and pressure drop of cooling water, temperature
increase of the water, and resistance increase of the coils were found to be of almost the expected values in thedesign. In Table 3 are listed the operational characteristics of the main coils and specifications of their power
supplies. Two types of power supplies (pS-l and PS-2) will be used. The difference of the magnetic field between
the four sector magnets will be adjusted by a bypass control circuit equipped in the PS-2 power supply.
Fabrication and assembly of the trim coils were also successfully completed. Specifications of power
supplies for the trim coils were decided on the basis of the measured data of the trim coil fields. Four types ofpower supplies (types A, B, C, D) totally having 61 control units are required to optimize the field. Total powerof all the trim coils' power supplies is estimated 216 kW.3)
Structural analysis of the sector magnet was performed with a computer code SAP_V.4) Preliminary
measurement of the vertical displacement and decrease of the gap width between the magnet poles due to magnetic
force was made at several positions along the pole's side edge by the manufacturer. 5) The result is shown in
Fig. 1. Because the difference between values for the two magnets amounts to about 50 pm at most, it will pose
no problem on the junction of the magnets with other parts such as the vacuum chamber or the RF resonators.
Detailed measurement of these values will be performed when the four sectors will be delivered to our institute.
It was found that the completed sector magnets have good performance in accordance with the design andthat they do not require a serious modification. The remaining two sector magnets are currently being
manufactured by SHI. The whole sector magnets will be delivered at the end of 1983. The construction of thewhole magnet system is scheduled to start at the beginning of 1984.

185

o
o

Distance a long th e side edge of the pole

100

200

E
E

:~

£

u

/ : P 1 00kG.!!!

~~.--.~/ ; .
~~
·~.IO

0

0. - - _ - 0 .

.3:
Cl.
C\l

tlO

0.1

(l

".~'O--_-.~--_

"

'0

"

JF. ')~--"'0- __ ~~ •''0........

Q)
if)

C\l

-0-

Q)

.......

U
0.2
Q)
0

. _ . W Secto r
0 - - -0 N

01

Sectorj } _........

I

II

I

/

kG --..0-0....___

1S/kG- -. -d

I I

/
/

/

P

Decrease (8) of the pole gap
Fig. 1.
width for the two sector magnets (named
by Nand W sectors) due to magnetic
force measured at several positions along
the pole's side edge. Values are given
as a difference between the values
measured with and without magnetic
field. (taken from Ref. 5).

References
1)
2)
3)
4)
5)

S. Motonaga, H. Takebe, A. Goto, T. Wada, J. Fujita, N. Nakanishi, Y. Yano, N. Kishida, I. Yokoyama,
I. Takeshita, H. Saito, and T. Sato: p. 186 in this report.
S. Motonaga, H. Takebe, A. Goto, J. Fujita, T. Wada, Y. Oikawa, I. Takeshita, and Y. Ikegami: RIKEN
Accel. Progr. Rep., 15, 162 (1981); Reports I.P.C.R. (in Japanese), 57, 156 (1981).
A. Goto, H. Takebe, S. Motonaga, Y. Yano, N. Nakanishi, and T. Wada: p. 197 in this report.
M. Deto, M. Hara, and T. Wada: p. 193 in this report.
H. Saito, T. Sato, and J. Abe: Proc. 4th Symp. on Acce1. Sci. and Tech., p. 299 (1982).

186

N -17.

Measurement of the Magnetic Fields of the RIKEN

sseS. Motonaga, H. Takebe, A. Goto, T. Wada, J. Fujita,
N. Nakanishi, Y. Yano , N. Kishida, I. Yokoyama,
I. Takeshita, H. Saito, * and T. Sato*

Excitation characteristics and detailed field distributions obtained with the two sector magnets,
and the magnetic fields produced by some trim coils were measured at the factory of Sumitomo
Heavy Industries (SHI) in April and August 1982.
The magnetic field of 15.5 kG, which is the maximum base field required for the RIKEN
sse, was achieved with the magneto-motive force of 1.28 X 105 ampere turns. The excitation
characteristics of the sector magnet are shown in Fig. 1. The magnetic field of 15.8 kG was
obtained at the magneto-motive force of 1.35 X 10 5 Ampere turns, which is the maximum in thedesign. The measured values were found to agree well with the calculation.
Sector Mag net

20

Calculat ion- - 0 - - Calc ul ation
6% increase ( yoke )- x - Measurement~---e -· -15.5kG
1--- - _ _..::....::..c..

_.... - _~1/~7· I~

15

~

I~

(1)

c
OD
<U

L

5

/

/

31 March 1982

I ( A) B ( kG )500 10.1
800 14.37
1 000 15.68
1100 16. 17

Magnet moti ve force (x 10 5 AT)

Fig. 1.

Excitation characteristics of the sector magnet.

Measurement of map fields for use in the orbit calculations was carried out with the two
sector magnets set perpendicular to each other. The measurement was made at base field of
7, 11, 14, 15, and 15.7 kG, over the region from 0° to 45° using the computer-controlled magnetic
field measuring system. 1) Typical results of the base field profile along the hill center line areshown in Fig. 2. Figure 3 shows changes of the effective sector angles obtained by the effective
boundaries of the magnetic field with one or two magnets. The angle of effective boundary
decreases by about 1° in the injection region. This decrease is due to the shape of the sector in* Sumitomo Heavy Industries Ltd.

187

100

B Center~-....;-.//

I- -- B=7.11kG- - B= 15kG--- - B= 15,7kG

95

(f)
(l)

--+-- With one sec tor magnet

52°

B= 15kG

2:'-0--

With two sector magnet

Q()
(l)

~

BIB
.~

51 °

(l)

R =2 10

Q()

~

100

50°

.2

~

()

(l)

~ 49°

0:::

(l)

>

95

100

200

300

Radius ( cm )Fig. 2.

Radial distributions of themagnetic field normalized to the fieldvalue at the radius of 210 cm.

Radius ( cm )Fig. 3.

Change of the sector angles

obtained by effective field boundaries
along the radius.

this region. These edge fields could be adjusted to correct for such a decrease in the angle ofeffective boundary with iron shims or central region trim coils. At this stage, however, we
decided not to use these iron shims because it was found that the trim-coil currents required in
the central region can be kept below a reasonable value (less than about 500 Amps.) if no ironshim are used. .Trim coils' fields were measured along the hill center line at the base fields of7, 11, 14, 15, and 16 kG for appropriately chosen eight trim coils. Optimization of the trim
coils' currents for the isochronous field was performed using these fields together with thebase fields. 2)
In order to check the accuracies of the approximations for Br, Be, and Bz which are used in
the orbit calculation programs, we made measurement on map fields of Br, Be, and Bz off themedian plane at the base field of 7 and 15 kG. Analysis of these data is now in progress.
The field measurement with the whole magnet system are scheduled to start in the spring of1984 after the four sector magnets will be delivered to our institute.

References
1)
2)

H. Takebe, I. Takeshita, J. Fujita, I. Yokoyama, T. Wada, S. Motonaga, and T. Sato: p. 188
in this report.
A. Goto, H. Takebe, S. Motonaga, Y. Yano, N. Nakanishi, and T. Wada: p. 197 in this report.

188

N -18.

Magnetic Field Measuring System for
the RIKEN

sse Sector Magnet

H. Takebe, I. Takeshita, J. Fujita, 1. Yokoyama,
T. Wada, S. Motonaga, and T. Sato*

A pneumatically driven magnetic field measuring system was designed and constructed. It can cover thearea over 180° of the beam orbit plane in the sse. The magnetic field of the two sector magnets, constructed
this summer, was measured by this system. I)
Field mapping area necessary for the orbit calculations has different radial range in each azimuthal zone asseen in Fig. 1. Table 1 shows the radial range and steps in each azimuthal zone of 45° mapping area measured inTable 1.

Step and range of measuring area of 'MAP1' program for an orbit calculation. (0 = 0 means
magnet centre line, 0i initial angle, ~ initial radius, and Rr final radius.)

Zone

Oi

0°
10°
18°
22°
26°
29°

#6
#5
#4
#3
#2

#1

10°
18°
22°
26°
29°
45°

60

10°
8°
4°
4°
3°
16°

Step

1°
1°
1°
.25°
0

.5
1°

NO

11
8
4
16
6
16

Ri

Rf

6R

(mm)

(mm)

810
810
770
690
690
690

3810
3770
3770
3690
3690
3690

Nr

(mm)

Step
(mm)

3000
2960
3000
3000
3000
3000

20
20
20
20
20
20

151
149
151
151
151
151

w- Se ~ tor

fTTTTTT'TTl

o

Of

1m
~~= "Map 1 ., Measuring area

Table 2.

Actual moving time of the Hall assemblyfor one step cycle.

N- Sector

Direction

Step

Time

R

5mm
{ 20mm1 sec
1.6 sec

0.25°

I

E- SectoroFig. 1.

Sector magnets and the area which wereused in the measurement in the summer of 1982 by'MAPl' program.

* Sumitomo Heavy Industries, Ltd.

0.25°

1

1.0

0

2 sec
(Hill & Valley)
4 sec(Magnet edge)
2.5 sec(Hill & Valley)

189

Fig. 2.
Plan view of mechanical part of the magnetic fieldmeasuring system.

this summer. Hall assembly, which contains magnetic field detectors, has a radial length of 2660 mm. It has toclear gap spacers, and injection and extraction elements. In order to get an accurate positioning of the Hall
assembly and to make tension of the rotating assembly small, three pneumatic pistons are equipped to the rotatingassembly for each direction (Fig. 2). Two pistons moving 5 mm and 20 mm in the radial direction, and the othertwo for 0.25° and 1.0° in azimuth are connected in tandem, respectively. The third piston for each direction isused for locking the assembly. Figure 3 shows the radial driving pistons in detail. Moving time of the Hall
assembly in the azimuthal direction is different at each position because of the eddy current by a fringing field.
Accordingly, in order to determine the timing for the locking piston, the actual position of the driving piston isdetected by a potentiometer in each direction. Table 2 shows the actual moving time of the assembly for one
step cycle. Two rotary encoders (COPAL: RE'-20A) and up-down counters indicate the coarse position of theHall assembly in order to check the piston error.
The system is controlled by LSI-ll micro computer 2) (Fig. 4). Twenty sets of Hall probes (SBV- 601 - s1)
are mounted radially in line with pitch of 140 mm on the Hall assembly. Their twenty outputs and otheranalog signals (current monitors etc.) are led to a relay scanner (FLUKE: 2204A) through thirty pairs of twisted
cables (20 m long) and measured by a DVM (8502A). Sampling time of the DVM had to be longer than 250ms/
channel because of noisy environment in the big factory.* Reading error of the DVM was less than 2 p.V whichcorresponds to 0.6 Gauss of field. Hall control currents (200 rnA) are connected in series and stabilized with anaccuracy better than 5 X 1O-~

190

'"

_0

",N

Rotary encoder -

a.
o W'

Uo:::

I

65 ----lf~t -, Potent iomet er I

Rad ial driv ing pi ston s

Fig. 3.

Details of the piston driving system for radial direction.

Rotating assy (Radial guide)

Hall assembly

Magne ti c fi eld measuring sistem for the RIKEN

sse

Amp. connecto rs with multiple
position on A 19' rack panel-

I

1\r________~G~P~- IB~B~u~s --------~

Fig. 4.

Schematic diagram of the electronical system.

Most of programs are written in FORTRAN. The subroutines for CAMAC control and colour graphic control
are written in MACRO-assembly language. These programs are developed not only in LSI-II but also in
FACOM M-200 large computer.

191

(a )

Ll B = BNMR- BU •L
Ll BHI
o 30. 0°C + lOG... 20 3°C++ 40.2 °C
+ +

(b )

LlB
+ 40°C/3 = 40 PPM r C

+

-+~

B

"" ""

"~... 20 kG

0

+ lOG

HI

~ + 0""

0

""

~
lOkG

~,

°

?20kG ( NM R)

20°C'"
- lOG
H2

-lOG

+ lOG

H2

+ lOG

+

/3 =36 PPMr C++-+~-----0+1
9
'?

o

0

0

"'~) OkG ..

1

0

0

20 kG

0

a

~,

~

lOkG

920kG ( NMR)

-lOG

+ lOG

+

~
~+,
6
0,
~

H3

+ lO G/3 = 44 PP Mr

+

+

('j

O~QkG
-lOG

+

~

- l OG
H3

"" ""

...

° 20kG

~

0

<f+

""

0

q
lOkG

c
~20kG ( NMR )

'ill
e

- lOG

Fig. 5.
Fitting errors and temperature dependence of the Hall characteristics by
5th order polynomials for 30° e 's data.

Hall calibration polynomials (5th order and one temperature coefficient) were determined for 24 sets of Hall
probes previously. Figure 5 (a) shows fitting errors of calculated field in 20° C and 40° C data from the 30° C
data's polynomials. Figure 5 (b) shows similar errors but compensated with a temperature coefficient as givenby the following equation:

where t is the temperature, (3 the temperature coefficient and V the Hall output voltage. Ao was small enough tobe neglected (about ± 0.5G).
Figure 6 shows an example of contour lines of the magnetic field obtained from the "MAP 1" data. In order
to .reduce systematic errors caused by a change of the Hall characteristics or by some unknown reasons, eachneighbouring Hall probe can measure the same point by moving the assembly 140 mm radially. Figure 7 shows
the difference between the calculated fields of the above neighbouring Hall probes at the same point, which are
obtained from the "MAPI" data. The difference, 6Bn , is given by

where Bn is the calculated field for the Hall number n. Field strength at the magnet hill is about 15.7 kG. Large
difference (6B) can be seen in the fringe field of 10 k - 13 kG, which are caused by a setting error (± 0.2 mm) of
the probe in the azimuthal direction. These setting errors can be reduced by adjustment of the probes position,
instead of the measurement for the center of the Hall probe active area.
Small difference in a flat field of the magnet hill (about 15.7 kG) are used for actual Hall re-calibration
factors. 3)
At the measurement, the magnetic field is calculated using the calibration polynomials and displayed on adigital plotter or a colour graphic unit (OKI: IF - 800). The data are recorded in an 8 inch floppy disk, andcopied to the magnetic tape to be processed in M- 200 large computer.
Total measuring time for 'MAPI 's 45° mapping area as that for the Table 1 was two hours and a half. Thismeasuring time will become short in the accelerator room, because of more quiet environment.

192
90°

80°
'. f·

I.

, , , , , ,7 0 °

10°

100

200
R

Fig. 6.
LlB+20G

t:,.B 10

t

-20G
+20GF
6B~ 20GE+20G

t:,.B a-20G

I

~B ( NMR ) 20kG

6B~ 20G~

~

20kG

~

='=
~

L

20kG

::;::>- 20G~---------+20G
6B6
~
-20G

20kG

-20 G

~

~!

~------.~::::::=:=,I~~

I

20kG

-20G

t:,.B~20 G~

~I

-20G

"

6B~ 20G ~

~

I

20kG
I

20kG

-20G

t:,.B ; 20G~

I

20kG

-20G

~~-----~===--L----~----~20kGl~
6 B +20G
5-2 0G
6B+20G~
4

0°

300

em )

Contour lines of the magnetic field of 'MAP 1' data.

=::::::"7r~
6B+20G
7(

6B ; 20G ~

=

-20 G

2OG
20kG

+20G ~

6B 3
r----=~==~~~~~----~20kG-20G+20 G~

6B 2f-~--=--==----=---~~====~===",-------J!2'0 kG-20 G~~--""'"'==LL",.--===±:::==:::::6=--..L----6B +20G
I
kG
20
-20 G

6B:

L.=:::,.

~

~

&

I

20kG
I

20kG

-20G

~V
6B +20G
l3-20G

6B~20 G~

I

c±:.

-20G

20kG
I

20kG

-20G

t:,.B~ 20G~

I

=b

I

20kG

Fig. 7.
Differences of the calculated field of two Hall probe outputs measured at
the same points. This is obtained by processing of the 'MAPl' data.

References
1)
2)
3)

S. Motonaga, H. Takebe, A. Goto, T. Wada, Y. Oikawa, 1. Takeshita, Y. Ikegami, J. Abe, T. Tsukumo,
H. Saito, and T. Sato: p. 183 in this report.
J. Fujita, T. Wada, and H. Takebe: RIKEN Accel. Progr. Rep., 123, 15 (1981).
H. Takebe, 1. Takeshita, J. Fujita, 1. Yokoyama, T. Wada, S. Motonaga, and T. Sato: Sci. Papers 1.P.C.R.,
77, 20 (1983).

193

N - 19.

Structural Analysis of Sector Magnet
by Finite Element Method

M. Deto,* M. Hara, and T. Wada

1

Results of two dimensional analysis have been reported in previous reports. ),2) The analysis by three
dimensional code SAP-V 3) has been done this year. In this analysis we investigated three kinds of structure
which are the same as those of the previous reports. To this structure, two supporting feet made of soft iron are
installed under the magnet. The nodal points on the floor are fixed in x, y, and z directions. Eight node brickand truss elements are used and total number of elements is now 2656. The magnetic and vacuum forces loadedon the pole face elements are 9.75 kg/cm 2 and 1.033 kg/cm 2, respectively. Figure 1 shows the subdivisions forthe three dimensional analysis.
NOO[ l'Io.

~4(DIS . .v.X'(ST'R£SS.P'1.A..X)

Fig. 1.

Subdivisions forthree dimensional analysis.

Fig. 2.

The calculated deformationof the whole magnet. The solid and brokenlines show the shapes before and after
deformation. Deformation is exaggerated.

(1) Static analysis
Figure 2 shows the calculated deformation of the whole magnet seen from y direction. Figure 3 shows theazimuthal and radial distributions of vertical deflections of the upper and lower pole faces. It can be seen thatthe deflections of the nodal points along the magnet center decrease by about 23 % for both upper and lower
poles, if small gaps of I mm are provided in the pole bases. From the azimuthal distributions for the upper pole,
it can be seen that the deflections decrease by about 10 ,..., 64 % by the effect of small gaps, although for the
lower pole the effect is not so large.
Comparing these results w~th those of FEM - II code,4) it is found that the deflections are 2 times and 3
times as large as those of the two dimensional analysis for the structures without gaps and with gaps, respectively.
The maximum deformation of the supporting feet is 120 p.m and the stress is much smaller than the allowed one.
2
The maximum compressive stress of the gap spacer is larger than that of the feet. It is 13.4 kg/mm but stillmuch smaller than the allowed compressive stress (52 kg/mm~ and yield strength (21 kg/mm2) of the stainless steel.
The value 13.4 kg/mm2 agrees quite well with the value 13.84 kg/mm2 of FEM - II code.

*

Colleged of Humanities and Science, Nihon University.

194

UPPE R POL E

LOWE R POLE

Azimuthal distributi on ( jim )346--~ 464--o239

Azimutha I dis tri bution,----\

rf1-----/1~5359

500 1 000 1 500 2000 2500 3000 (em)o

500 1 000 1 500 2000 2 500 3 OOO( em )~.~-~~~o_ .- with Gap
Cum) -- -- without Gap--- with Gap
Cum ) - --- without Gap

Fig. 3.
The azimuthal and radial distributions of verticaldeflections of the upper and lower pole faces.

. illl ilBI IIUilllllll1 MHfl·II:T:~i :I ru ru In~'jll U\
1
II lJ II II nllD~~ I

I T II I J! 1011 I I
III If II I III IIIIKIIi

I

I' "

Y Z plane
I

..

N
I
I

1' 1

I
I

I

:1
1:1
;~ ,

~ .

,

.
4"

Mode 1

f=11.592 Hz

Mo de 2_f'"y~ -:; \jI

i ilUri l.J\.- .

I

Ir

"

-

IT

-

I

..

o.

1

l

•1

~

"~~

".

,

.

- n

The oscillations of mode 1 to 3.

0I

x Z plane

Fig. 4.

'/

f=27.741 Hz

""'

I

If

':71

~

Mode 3

f=14. 849 Hz

f.1..\1~~ ; .. /'.11:-

~

II,

II
I lUI

III! I· I

1-X/'

llJ. I

~

~ w7

1

195

(2) Eigenvalue/eigenvector solution
In dynamic analysis, only solid type elements are used. The number of nodal points and elements are 2407
and 1656, respectively. Table 1 lists the calculated characteristic frequencies of lower 10 modes. Figure 4 shows
the oscillations of mode 1 to 3.
(3) Forced dynamic response by mode superposition
In order to investigate the strength of supporting feet, a froced dynamic response analysis was done using
mode superposition method by SAP-V code. The frequencies of lower 5 modes are used. For the input data,
The
used are the numerical data of earthquake in the offing of Miyagi prefecture on 12th of June in 1978.*NS and EW components of the earthquake waves are forced in x and y directions, respectively. A damping factorof 0.02 is applied for the magnet. The response histories are calculated for 25 seconds at the time step of 0.002
second. It is found that the displacement is largest at the top of magnet while the stress is largest at the
supporting feet. Table 2 shows the histories of displacement for the top of magnet, and Table 3 shows those ofstress for each supporting foot. Figure 5 shows the NS component of earthquake waves and response histories
of displacement and stress. It can be seen that the supporting feet can withstand the earthquake of this strength.
It should be noted that in this dynamic analysis the displacement and stress by static forces are not inc1~ded.
Table 1. Characteristic frequencies.
Mode

Frequency (Hz)10.2078

2
3
4
5

6
7
8
9
10

18.359624.518752.357870.503870.9365
82.1998
110.356
119.129144.263

Table 2. Displacement maxima.
Mode
No.

Displacement
component

Maximum
value (j.un)Time atItl,ax. (s)

54
54

x
y

42.64055.506

13.96
14.02

Table 3. Stress maxima.
Elm.

No.

Stresscomponent

Maximum
value (j.tm)

Time atmax. (s)

Gxx

5.289
0.838
33.331
0.029
0.367
9.473

13.96
13.96
13.96
13.98
13.98
13.96

3.959
0.104
2.718
0.014

13.96
13.96
13.96
13.96
13.96

Gyy
Gzz

1318

Gxy

ayz
G zx

1501

I

G xx
G yy
a zz
axy

1

G yz
G zx

0.059
1.314

13.96

* Strong Earthquake Motion Observation Center, Earthquake Research Institute of Tokyo University.

196

THE EARI'HQUAKE OF MIYAGI - KEN OFF(a)

Kr SHIcx;AMA HARBOR

1978/06/12

17:14

MAX.ACCEL ;; -314.3 Gal- NS -

14.(1(1'0.('1(1;4. . tlO

1'.('1010.('\('\n.oo

2(,('(1

H.C'lCI11 . 0('1) ('1.

{tolln[.IS((O"';OI

DISPLACEMENT OF NODE.NO.

o'" I N'54 (X-direction)

MAX.DIS ;; 4.264E-2(rnm)

MAX. TIME ;; 13.96

sec

~_

; \ . l'lC'

1rn(

STRESS OF ELM.NO. 1318

\ Ii . l oCI

I,.

(l[I

:0 . (,e"

~1

1'1"

15lCONOJ(ZX-copn)

MAX.STRESS;; 9.473E-3
MAX.TIME ;; 13.

( C)

6

sec

Fig. 5.

The time histories

of displacement and stress.
(a) The NS componentof input earthquake wave ,(b) The time history of
displacement of nodal
point number 54,( c) The time history of
H .OO

1 I rI(

16 . 00(~l COIIO J

10·0 010.ClOn .oo

11 . 00

1 ~ · N'

stress of element number
1318.

References
1)

Y. Ikegami, T. Wada, and M. Hara: RIKEN Accel. Progr. Rep., 12,166 (1981).

2)

Y. lkegami, T. Wada, and M. Hara: Reports I.P.C.R., (in Japanese), 57, 177 (1981).

3)

K. Bathe, E. L. Wilson, and F. E. Peterson:

4)

H. Togawa: "A Guide to Finite Element Method", (in Japanese), Science Co. Ltd., Tokyo (1979).

SAP- V User's Manual, U C Rep. No. EERC , 73 - 11 (1974).

197

N -20.

Measurement of the Trim Coil Fields and Determination ofTrim Coils Power Supplies for the RIKEN SSC

A. Goto, H. Takebe , S. Motonaga, Y. Yano,
N. Nakanishi, and T. Wada

On the sector magnets of the RIKEN sse are set 29 pairs of trim coils, the radial positions and widthsof which were designed on the basis of model measurements and field calculations. 1) To determine these parameters,
a computer code was used that can optimize currents of the coils with the least-squares fitting method. 1)
We measured last summer the field distributions of trim coils along the hill center-line of one of the two
sector magnets which had been completed by then. 2) The measurements were made for trim coils No.3, No.7,
No.9, No. 14 - 15 , No. 18 - 19 (hyphen means that these coils are connected in series), No. 22, No. 26, andNo. 28 at five base fields of 7, 11, 14, 15, and 16 kG. A current of each trim coil was set to be 150 and 300
Amps. We did not make measurements in the case of current higher than 300 Amps because of the limitation of
the capacity of the present power supply. With respect to the measuring system, see Ref. 3. Figures 1 and2 show the magnetic field distribution of each trim coil at the base fields of 7 and 16 kG, respectively. The field
distribution presents a step-wise profile. It can be seen that the radial field distributions are flat in the case of
BASE FIELD. 7 KG

50

BASE F I ELD.

50

16

KG

'00
RADIU S (e M)

-30

- 30

Fig. 1.
Magnetic field distribution of eachtrim coil at a base field of 7 kG. Each trim
coil's curr~nt is 100 Amps. Note that thereturns of trim coils from No.1 to No.7 arewound around the nose of the pole.

Fig. 2.
Magnetic field distribution of eachtrim coil at a base field of 16 kG. Each trim
coil's current is 100 Amps. It can be .seen thatthe distributions of undershoot and overshootfields decrease radially because of saturation of
the yoke.

x

No.3

x

• No.7

~ 100

x

if)

x

::J

m

X

~

100

x

~

No.3

• No.7
x

x ,.

if)

G

::J

OJ'"

<J

G

50

OJ

<J

cO

m

50
0

10

5

<J

15

I-~---x_----~I_X ____~~~I-----..

X

X

~

6 B1

0

5

Base Fie l d ( kG )Fig. 3.
Variation of the undershoot field (6B 1 ) andovershoot field (6B2) with respect to the strength ofbase field for the trim coils No . 3 and No . 7. Eachtrim coil's current is 300 Amps.

10

15

Base Fie l d ( kG)

Fig. 4 .

Variation of the field step height(6B = 6B 1 + \ 6B2\) with respect to thestrength of base field for the trim coils No. 3
and NO.7. Each trim coil's current is 300
Amps.

198

7 kG, but that the field strengths decrease with radius in the case of 16 kG. This difference results from theeffect of finite permeability of the return yoke. 4) The saturation effect can also be seen in the magnitudes of theundershoot and overshoot fields, Figure 3 shows the variation of the maxima of undershoot field (6B 1) andovershoot field (6B~ with respect to the base field for trim coils No.3 and No.7 whose returns are wound aroundthe nose of the pole. The variation of field step height (6B = 6B 1 + i 6B21) is given in Fig. 4. Figures 5 and 6
show the same quantities as in Figs. 3 and 4, respectively , for trim coils whose returns are wound around the back of thepole. Values of 6B 1 and 6B2 change beyond the base field of about 11 kG. As can be seen especially in Fig. 5,
the larger the area of the pole surface which is surrounded by the trim coil and its return, the more drasticallythey change. In all cases we have obtained a very good linearity of the field step height to the current. Furthermore, we measured trim coil fields for two cases: in one case all the trim coils were excited at 150 or 300 Ampsand in the other all trim coils except one were excited. The trim coil field distributions obtained as the differencesof these two measurements were found not to show such a large change from the before-mentioned ·distributions
as was seen on the cyclotron at IUCF. 5)
The magnetic field distributions of coils other than the eight coils were obtained by interpolating themeasured data. We have calculated the optimal trim coils' currents for isochronizations in cases of seventeen
typical ions using the above-mentioned program code. In Fig. 7 is shown, as an example, the comparison of thecalculated magnetic field distribution formed by the trim coils with the isochronous field for the 135 MeV/u C6 +
ion.

::::J
<Cl

~

<:..:)

IAJ

ClJ'"

<J

~

'"

50

<J

cD

x
0

. . '".

0• No.9No.14-1 5
o No. 18-19.. NO.22
x NO.26
o NO.28

NO.9
No. 14-15
o No. 18 -1 9.. No.22
x NO.26
o NO.2 8
o

6.

6 B2

~ 100

100

6.

(f)
(f)

::::J
<Cl

<:..:)

50

ClJ

5

a

10

<J

15
~
~

Base Fi el d ( kG )

..

0

0
~

5

.
~

10

15

Base Fiel d (k G)

'" '"

6B \

Fig. 5.
Variation of the undershoot field (6B.) andovershoot field (6B~ with respect to the strengthof base field for the trim coils No.9 , No. 14 ~ 15 ,No. 18 -19 , No . 22, No. 26, and No. 28. The values
change drastically beyond the base field of about 11 kG.

17.0

<3
..Y:

16.0

Variation of the field step height (6B =6B. + I 6B2 I ) with respect to the strength of basefield for the trim coils No.9 , No . 14 - 15, No . 18 - 19,
Fig. 6.

No . 22, No. 26, and No. 28.

------- ISO--- - BASE
- - CAL

:5
QO
c
~

15.0

if)
-0
(l)

Fig. 7.
Comparison of the calculated magnetic
field distribution formed by the trim coils with theisochronous field for acceleration of the C6 + ion to

14.0

l..L.

13.0

R'NJ

i

100

200

R

300
(em)

400

135 MeV/u .

199

Table 1.

Maximum and minimum currents of each trim coil for isochronization andresistances of the coils and cables. Coils No.4. 5.6,26.27. and 28 are
also used for harmonic fields .
Sector-----~

Coil No.

PowerSup. No.

Resislanl:eof coil(mS1)

Curreut

M~.
(A)

S

(A)

7.8

0

0

2

7.5

0

0

3

7.89

47

399

W

N
E
Type
Resistance of
coil and cables
(mn)

(2
12.5

C'2
9.8

C1
21.4

4 - H

2

7.6

144 476

03 03 0303
12.3 9 .6 10.5 13.4

5 H (74A)

3

7.9- 17 404

03
12 .6

03 03 03
9 .9 10.8 13.7

6 H (74A)

4

7.8

-82

223

02
12.5

02 02 D2
9.8 10.7 13.6

7

5

7.5

- 203

29

BI

B1
BI
41.6

8

6

9.4

-48

297

Al
43.4

9

7

10.2

50

370

A2
46.6

10-11

8

15 .2

47

471

12-13

9

14.5

29

481

14 - 15

10

13.9

40

504

16- 17-20- 21

1112.4 + 11.99440

18- 191212.1

19 486

22

13

6.4

22

541

23 - 24

14

6.7 + 6.6

12

515

25

IS

6.6

9

380

26H (400A)

16

7.5

5

27H (400A)

17

7.5

28 - H

18

5.9
5.8

29

B3

B3
B3
66.6

B1

B3

A4
63 .8
B4

B4
B4
61.4

B4

A3
103.0
B3

B3 B3
54.2

B3

85

B5
B5
31.4

85

AS
58 .2
B2

B2
B2
32.2

B2

176

02
12.2

02 03 03
9.5 10.4 13.3

176

02
12 .2

02 03 03
9.5 10.4 13.3

0

0

01
15.2

01
9.9

0

0

02 02
8.8 11.7

In Table 1 are tabulated the maximum and minimum currents for each trim coil obtained by calculations
for the seventeen typical ions (6.5 MeV and 9.3 MeV Protons, 9.2 MeV H;, 28 MeV 3He+, 7 MeV C3+, 48 MeV
C6 +, 84 MeV C6 +, 23 MeV Arll+, 152 MeV Ar 1S +, 49 MeV Kr 17 +, 180 MeV Kr24+, 77 MeV Xe 23+, 115 MeV Xe3()+-,
121 MeV Pb 30 +, 181 MeV Pb 36 +, 138 MeV U33 +, and 200 MeV U40+). Trim coils No.1, 2, 28, and 29 are notused for the isochronization but for compensation of fields around the injection or extraction elements. Trimcoils No.4, 5, and 6 and trim coils No. 26, 27, and 28 are used for harmonic field excitations or compensationof their undershoots in the injection and extraction region, respectively. Field deviation from the isochronous
field was found not to become larger in spite of serial connections of the coils No. 10 - 11, 12 - 13, 14 - 15,
16-17-20-21,18-19,23-24. Trim coils No.8, 9,12-13,16-17 - 20 - 21, and 23 - 24 are respectively

200

connected in series through four sectors. These coils are excited with power supplies named type A. Currents oftrim coils No.7, 10 - 11, 14 -15, 18 -19,22, and 25 are adjusted for each sector magnet by a bypass control
circuit I) with power supplies of type B. Each of the coils other than these is excited independently for eachsector magnet using power supplies of types C and D. Total resistance of each trim coil and its connection cables
are also listed in this table.
Vol tage and current specifications of the trim coil power supplies were thus decided and are listed inTable 2. Each of power supplies of types AI' B1, and D has a polarity switch. The total power of all the trim
coil power supplies is estimated to be about 216 kW.
Table 2.

TypeVoltage and current specifications and types of the trim coil power supplies. The '+-' signmeans that the power supply has a polarity switch.

I(Max.)I(Max.)

(A)

(A)

Pol.

V(Max.)(V)+-

R(Coil + Cables)

Sets

Total power

(mD)

(kW)
4.7

Al

330

0.25

14.3

43.4

A2

410

40.0

19.1

46.6

7.8

A3

490

1.0

50.5

103 .0

24.7

A4

530

15 .0

33.8

63 .8

17.9

AS

560

1.0

32.6

58.2

18.3
Branch !(Bypass)

Bl

230

B2

420

41.6

4

+-15

2.2

50.0

13.5

32.2

4

-50

5.7

B3

530

50.0

61.0

115.0

B4

8

-50

32 .3

550

40.0

33.8

61.4

4

- 40

18.6

B5

590

50.0

18 .5

31.4

4

- 50

10 .9

CI

450

1.0

9.63

21.4

C2-1

500

1.0

4.9

9.8

I )

C2-2

500

1.0

6.3

i 2.5

1 J
1)
1 J

1.6

~}

18.6

I
I

42 .7

Total

215.9 kW

5.0

+-

9.6

Dl-1

250

0.5

+-

2.5

9.9

01 -2

250

0.5

+-

3.8

15 .2

02-1

400

0 .5

+-

3.92

9.5,9.5,8.8,9.8

02-2

400

0.5

+-

4 .68

10 .7,11.7

D2 -3

400

0.5

+-

5.0

12 .2 , 12.2, 12.5

02-4

400

0 .5

+-

5.44

13.6

03-1

550

0.5

+-

5.45

9.6,9.9

D3 -2

550

0.5

+-

5.94

10.4 X 2,10 .5 ,10.8

D3-3

550

0.5

+ .-

7.54

12.6,12.3

4.3
5.6

1

2
4
6

13.3 X 2, 13 .4, 13.7

References
1)

H. Takebe, A. Goto, S. Motonaga, T. Wada, Y. Oikawa, and I. Takeshita: RIKEN Accel. Progr. Rep., l5., 173

2)(1981).
S. Motonaga, H. Takebe, A. Goto, T. Wada, J. Fujita, N. Nakanishi, Y. Yano, N. Kishida, I. Yokoyama,

3)
4)

I. Takeshita, H. Saito, and T. Sato: p. 186 in this report.
H. Takebe, I. Takeshita, J. Fujita, I. Yokoyama, T. Wada, S. Motonaga, and T. Sato: p. 188 in this report.
E.D. Hudson, J.A. Martin, M.L. Mallory, F.E. McDaniel, and F. Irwin: Proc. 7th Int. Conf. on Cyclotrons

5)and their Applications, p. 201 (1975).
D.L. Friesel and R.E. Pollock: IEEE Trans. on Nucl. Sci., NS-22, 1981 (1975).

201

N-21.

Beam Extraction System for the RIKEN

sse (II)

Design Calculation of Magnetic Deflection Channel

N. Kishida and Y. Yano

The beam extraction system for the RIKEN SSC was previously reported. 1)-3) This system consists of anelectrostatic deflection channel, two magnetic deflection channels (MDCI and MDC2) and two uniform-fieldbending magnets. Required characteristics of each element are tabulated in Ref. 1. The present report describes
the calculated results of the magnetic field distribution by the designed MDC systems.
Requirements for the magnetic channels are quite severe:(1) MDCl and MDC2 must reduce the magnetic field of sector magnets by 0.05 T and 0.17 T, respectively,
for the case of extracting 1'c6 + ions at 135 MeV/u (this corresponds to the extreme case);(2) While reducing the field for the deflected beam, the channels must not unduly disturb the circulating
beam about 5 cm away from the deflected beam, that is, harmonic fields in this region must be small;(3) As for our variable energy SSC , the channels must be capable of producing a wide range of magnetic
field reduction;(4) Because of space limitations the current density of coils is usually very high. On the other hand, fromthe point of view of the cooling problems, it is required to hold the density below 50 A/mm 2 .
We have three possible ways to construct the channels that satisfy the above requirements:(1) by a septum coil inserted in the magnet;(2) by iron plates inserted in the pole gap of the magnet ;(3) by a combination of coils and iron plates.
A pure iron-plate channel is more attractive than a current septum channel from the economical point of view.
But it is impossible to adjust the field reduction without changing the thickness of iron plate. We cannot,
therefore, adopt this type of MDC system, so that we have studied the magnetic field distributions of the othertwo channels by model calculations using the magnetostatic field calculation program TRIM.4)
Design of the MDC systems was performed using the least-squares method similar to Ref. 5 in such a way
as to minimize field disturbance outside the channel and make the field distribution uniform inside under someconstrained conditions (eg. upper and lower limits of current density and series connection between some coils).
For this purpose, we developed a computer program MDCFIT which was coded using a sequential unconstrained
minimization technique. We assumed in this calculation that the finally obtained field will be produced bysuperposing the magnetic field of current cells upon the magnetic field by the sector magnet (the base field).
The base field was obtained by the calculation using the sector magnet with the cross sectional form which we
require so as to reproduce the excitation curve and the radial field distribution of the 1/3 scale model magnet.
The magnetic field generated by each current cell (output field) was obtained by subtracting the base field fromthe magnetic field which was calculated with a current cell inserted in a pole gap of the sector magnet.
The actual field calculation was carried out only for the case of extracting 1'c6 + ions at 135 MeV/u withthe base field of 1.675 T. The output field strength was found to be completely proportional to the current
value up to 2500 A. Figure 1 shows a typical example of the output field of a pair of current cell and proves
the correctness of the above statement. By means of a combination of the current cells, we compensate theovershoot output field outside the channel as much as possible within the distance of 6 cm from the deflected
orbit (D.O.) without affecting the last accelerating orbit (L.A.O.) and not to make harmonic fields.
Figure 2 shows a cross section of designed MDC 1. We placed the current cells not on the median plane
but shifted it in order to increase the field uniformity inside MDC 1, so that the required current became large incomparison with that for the configulation in which the cell installed in contact with the median plane. Figure
3 shows the field distribution near MDC I for the best fit to optimize the field uniformity and disturbance. The
undershoot field is found to be almost zero (0.01 mT). This combination of the coil currents requires four power

202

---.
~

t3

2
1
0

N

- 1

191
A
31 370 [8J
I

I

I

I

I

I

380

-2

!

•

r (e m)0.1

r= 373em~ 0.05I

o1It...-~-'-----'-~-=--:::,-:0. 5 1. 0 1.5 2.0 2.5....

1 ( kA)

-1.0

(b )

(a )

Fig. 1 (a) Typical field distributions produced by current cells with theconfigulation which is shown in the upper part of this figure.
(b) Relation between the current and the output field.

Fig. 2.

Schematic drawing of MOC 1. r denotes theradial distance from the center of the SSC. 13 and 14
indicate the currents that flow through respectivercompensation coils.

( em )

50
40
30
20
I-

10

E

0
cq

""l

- 10

r

( em)

-20
-30
-40

II =
490A
12 = 1099A
13 = - 314A
14 = 1989A- 50

Fig. 3.

- 60

MOel at Bbase = 1.675 T.

Magnetic field distribution produced by

203

suppries, which leads to a rise in production cost. In order to avoid it, wes therefore, searched another solutions
that generate almost the same field distribution as that of the best combination using only two independent
current. Those were found to be 11 = 13 = 471 A and 12 = 14 = 1104 A. We will adopt the latter combination inpractical operation.
If we insert a channel with two sheets of iron plate in the pole gap of the magnet which is installed
perpendicularly to the magnet pole face in such a way that the deflected beam is surrounded by the plates onboth sides, the magnetic field inside the channel is reduced to some extent in proportion to the thickness. If the
field reduction required by MDC2 must be realized by the same cross sectional structure as MDC 1, the current
density exceeds the upper limit (50 A/mm 2 ). Consequently we decided to adopt MDC2 that consists of current
cells and iron plates. The thickness of iron plates was selected so that the reduced field may take the value whichlies nearly at the middle of the variable range of MDC2.
Figure 4 shows a cross section of designed MDC2. The thickness of the plate is 0.25 cm. The platedecreases the base field by about 0.06 T inside the channel and produces an undershoot field of about 0.003 T
outside. This undershoot cancels out the overshoot field generated by the current cell in this case, so that any
compensation coil is not needed. But we adopt it to eliminate an undershoot field that may be produced in thecase of extracting other ions. The current cells were installed in contact with the median plane for the purposeof decreasing the power consumption. Figure 5 shows the field distribution generated by MDC2 in its
neighborfood. The field inhomogeneity is a little larger than that of MDC 1.
We tried to calculate the influence on phase-space ellipses for the beam caused by the field inhomogeneity
due to the MDC systems. We expanded the magnetic field inside MDC on the median plane along the central ray
as follows:
B(x) = B(O) { I + C (1)x + C (2)x 2 } ,(/~~/:0:;;~LI~~~~; ~~!~(1??~
365

370

373 375
r

380

(em )

385

Schematic drawing of MDC2.
Fig. 4.
The width of iron plate is 0.25 cm.

370

L.A.O.

D.O.

r ( em )- 0.05Iex:)"l- 0.1011 = 2169A

12 = 684A

I 3 = I 4 = OA

- 015

f\
-0.20

Fig. 5.
Magnetic field distribution produced by
MDC2 at Bbase = 1.675 T. The cut-off parts of field
distribution correspond to the position at which the ironpIa tes are installed.

204

Table 1. Field expansion coefficient of MDCl and MDC2.

MDCl-4.84 X 10-4

4.59 X 10- 4

MDC2- 2.06 X 10- 4- 1.26 X 10- 2

where x denotes the horizontal displacement from the central ray and e(1) and e(2) denote field expansion
coefficients of quadrupole and sextupole terms, respectively. The expansion coefficients of MDC are listed on
Table 1. The increase of phase-space area after passing through the beam extraction system was calculated using
these values with the aid of a program TRANSPORT. 6) As the result, it was found that the area of phase-space
ellipses increased by about 20 % in both horizontal and vertical phase spaces. This comes from large value ofe(2) of MDC2. As we cannot allow it, we have now to design another type of MDC2.

References
1)

2)
3)
4)
5)
6)

Y. Yano, N. Kishida, H. Takebe, A. Goto, T. Wada, and S. Motonaga: Proc. 9th Int. Conf. on Cyclotronsand Applications, Caen, France, p. 473 (1981).
A. Goto, Y. Yano, N. Kishida, and T. Wada: ibid., p. 439.
N. Kishida, A. Goto, and Y. Yano: RIKEN Accel. Progr. Rep., ii, 183 (1981)
J. S. Colonias and J. H. Porst: Magnet Design Applications of the Magnetostatic Problem called, TRIM,
UCRL-16382 (1965).
H. Braun: Proc. Int. Conf. on Magnet Technology, Hanburg, Germany, p. 1620 (1970).
K. L. Brawn, F. Rothacker, D.C. Carey, and Ch. Iselin: SLAC Report, No. 91, Rev. 1 (1974).

205

N -22.

Vacuum System of thesse

S. Nakajima, K. Ikegami, Y. Oikawa, and I. Takeshita

The vacuum chamber of the RIKEN sse is divided into eight parts, namely, four magnet
chambers, two valley chambers and two RF resonators. Details of the vacuum chamber as well as
pumping system are described in a previous report. 1)
Recently a decision was made to adopt a new type of RF resonator with a movable box tochange the frequency2) and accordingly the design of the resonator chambers was modified.
The vacuum enclosure of the RF resonator is made of stainless steel and its inner surface is
cladded by copper plate of about 7 mm in thickness. The RF resonators are anticipated to havelarge gas load and cannot be evacuated by the pumps equipped at the valley chambers, because
the magnet chambers form low-conductance passages of gas between the RF resonators and thevalley vacuum chambers. It is necessary to add pumps for the RF resonators. A turbomolecular pump having a pumping speed of 5000 P /sec for air and cryo-genic pumps having a total
pumping speed of 30000 I! /sec for air are mounted on the back side of each RF resonator.
A partition wall having 20 rectangular holes each of 20 mm in width and 1000 mm in heightis fixed in front of the cryo-genic pumps in order to shield them from the thermal radiation
caused by the strayed RF electric field. The partition is 30 mm in thickness, about 2700 mm inFig. 1.

Schematic view of the resonator enclosure.

206

height, and about 1720 mm in width. It is made of stainless steel c1added by copper. The space
where the RF electric field is generated is evacuated through the rectangular holes in the partition
wall with the pumps located on the back side of the resonator.
The total height of the resonator is 2700 mm. The valley vacuum chambers were enlarged
in height from 600 mm to 900 mm. Figure 1 shows the revised RF resonator with vacuum
pumps. The moving boxes are not drawn in the figure. Figure 2 shows the plan view of thewhole vacuum chamber. Volume and surface area of the chamber are as follows:
Volume:Magnet vacuum chambers
Valley vacuum chambers
Resonator vacuum chambers,...., 1.8 m 3"""5.4,...., 22.8

Total
Surface area exposed to vacuum:
Magnet vacuum chambers
Valley vacuum chambers
Resonator vacuum chambers
Elastomer 0 rings

80 m 226,...., 236

3

Total
r- - -- -- -- - -- i
I
I
I

I

I

I

I

I
I

I

I

I

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

r- -- - - -,I
I
I
I
I

')

I

:

I
I

I

I

:

I
I

:
I

I

IL __ _ _ _ _ ')C.P.

7------ - ,

i

I
I
I

I

I
I

I
I
I
I
_~ "' _ _ _ ____ JI( RF ) : Resonator vac uum chambe r( V) : Valley vac uu m chambe r( M) : Magne t vac uum chamber
C. P. : Cryo- pump
T.M.P. : Turbo- molec ul ar pump

Fig. 2.

Plan view of the whole acceleration chamber.

References
1)

K. Ikegami, S. Nakajima, Y. Oikawa, and I. Takeshita: RIKEN Accel. Progr. Rep. ,12, 200(1981).

2)

T. Fujisawa: ibid. , p. 196.

207

N -23.

Test of Model Pneumatic Expansion Seal

K. Ikegami, S. Nakajima, Y. Oikawa, and M. RaraA pneumatic expansion seal is to be used between each vacuum chamber section of the sse. Three 1/3
scale models of the seal were constructed and tested to investigate the performance. Using a finite element
method, the structural analysis of the seal was done.
In the previous test, a single D·ring of diameter 10 mm was put between two flanges, and the compression
force of about 11 kg/cm was applied to the O-ring by the pneumatic sea1. 1) The deformation ratio of the O-ringwas 15 %. No leakage was detected in the expansion of about 20 mm. We consider that squeezing force on
D-ring of more than 10 kg/cm is needed to keep vacuum-tightness.
hi. order to investigate the optimum applying pressure, relation between expansion length and appliedpressure to the seal was measured. The stress of the seal was measured with a strain gauge. The gap between thetwo flanges was fixed to be about 14 mm between each vacuum chamber. Pressure sensors whose thickness anddiameter are 0.6 mm and 6 mm, respectively, were put between the D-ring and the flanges. Forces squeezing
the O-ring were measured with them. Figure 1 shows the distributions of seal expansion and the squeezing force,in the case where the width and the thickness of seal are 100 mm and 1.0 mm, respectively. When the pressureof 1.0 kg/cm 2 was applied to the seal, the squeezing force at the straight section was about 10 kg/cm in the caseof A type seal (W = 100, T = 1.0), and 12 kg/cm in the case of B type seal (W = 120, T = 1.0). The squeezing
force at the circular section was, in both cases, half compared with that of the straight section. Figure 2 shows therelation between the squeezing force and applied pressure.

t>,1EASUREfl POINT

~

40

:r::

e-

L?

2

( W= 100, T =O.S,P= 0.5 KG/CM

30

)

Z
Ul
....l
L?

z

( W=120 , T= 1.0, P=l .S KG/CM

2

20

;:;
z

«
Po.

10

~

P=1.6 KG/ CM

2

Fi xed Gap 14 rTl11)

20
MEA SURED PO INTFIXED GAP 14 MM-

At the stra i ght section--- At t he Circular section

SEAL( W=100 , T=1. 0 )15
MEASURED PO I NT

Ev.......
01~ 10
P= 2.42=

2.0~: : :'.~.~.

~= 0.4..-------~oI
6~lEASURED

Fig. 1.

A Type Seal (W=100, T=1.0)• B Type Sea l:_ _(W=120,T=I.0)

I
7

8

10

POINT

Expansion distribution and squeezing force

distribution for A type (W = 100, T = 1.0) seals.

o

1. 0

2 .0

3.0

Applied Pressure ( kg/cm 2 )Fig. 2.
Relation between the force
squeezing D-ring and applied pressure.

208

20

APPLIED PRESSURE
P= 1.4 KG/CM

2

10
P=

3
MEASURED POINT

FIXED GAP 14 MM

T= 1. 0 MM
APPLIED PRESSURE
2
2.4 KG/CM

'"ua:
5: 10
Q

~

'"'"
~

~

MEASURED POINT

Fig. 3.
Distributions of the expansion and the force squeezing O-ring for the
improved pneumatic expansion seal. Filled circles: the measured value while
applied pressure increased gradually_ Crosses: the measured value while appliedpressure decreased gradually till 1 kg/cm 2 .

A Type Seal ( W=lOO, T=1. 0 )9
8-0-6,-//

Measured
Calculated

7
~

6

~ 5
c
~

4

~ 3

0
0.

~

2
I:J.

0

~

0,54

Applied Pressure

Fig. 4.

Calculated deformation of the A

type seal (W = 100, T = 1.0). A quarter ofthe cross-section is shown. The length in X
direction only is exaggerated by scale factor
2.5 .

1. 50
kg/cm 2 )Fig. 5.
Comparison of the calculated andthe measured expansion of the seal.

209

A model which has different widths in straight and circular sections was constructed and tested. This seal
has improved characteristics of the expansion distribution. Figure 3 shows distribution of the expansion andsqueezing force of the improved pneumatic expansion seal.
When the pressure was applied to the seal, the seal was deformed non-elastically if the force is stronger than
the substance's elasticity limit. Using the finite element method, the elastic and plastic analysis (EPIC) of the seal
was done two dimensionally. Figure 4 shows a quarter of the cross-section of the seal whose deformation was
calculated using the finite element method. When the pressure applied to the seal was increased gradually, only theregion A of the seal was deformed beyond the yielding point of the stainless-steel at first , and then the region B
also was deformed beyond the yielding point. A relation between the expansion of the seal and the appliedpressure was measured for a seal whose width and thickness are 100 mm and 1.0 mm, respectively. Figure 5
shows the results together with that calculated by EPIC code. The magnitude of expansion calculated by EPIC
is small compared with the measured value. The reason seems that the force generated by the applied pressure
to the seal exceeds the yielding point stress of the welding region. The detailed analysis of the seal is in progresswith the finite element method.

Reference
1)

C. J. van Lamp: NAC/AR/80-01 Annual Rep., p. 105 (1978).

210

N -24.

Preliminary Experiment on the Surface Cleaning of
the Vacuum Chamber for the RIKEN SSC

Y. Ishibe, H. Oyama, Y. Sakamoto, K. Ikegami,
S. Nakajima, Y. Oikawa, and S. Motonaga

The inner surface area of designed SSC vacuum chamber is approximately 350 m 2. In orderto achieve the final pressure of 10-8Torr in the chamber without baking, the rate of desorption
from wall must be decreased to the order of I 0-10 Torr i!jsec cm 2• Eliminating the contaminationon the surface, we can achieve the above value. The most common contaminants are hydrocarbons,water molecules and dust.
We are studying the methods which make clean the inner surface of the large vacuum
chamber. The degree of cleanliness is evaluated by the electron spectroscopy for chemical
analysis (ESCA). Material of the samples used in this experiment was stainless-steel AISI 304. To
eliminate the gross contamination, the surfaces were pretreated by means of glass beads blast; thesize of beads was 150 mesh. After such treatment, it was attempted to clean the surface byvarious cleaning methods.
The wide range energy spectrum of electron from the surface was measured by the ESCA.
Three typical cases are shown in Fig. 1. It is seen that the height of carbon peak is decreased
drastically in the cases (B) and (C) compared to that of case (A). The results obtained forsurfaces treated by various cleanirrg-methods are arranged in order of the height of carbon peak
and are shown in Fig. 2. With the decrease in the peak height of carbon from hydrocarbons, thatof iron increased remarkably. This fact shows that the surface became clean. The height and

A
(j)

c:::

2c:::
c:::

I

Fe

(a)

I

o

c

j

I

~~.

."

(~.~;.. '\",; :;'\;"1;;2·t.!~.•~.r ~~,/.;,:'u:-: .:. . ~.:":' ::·,···.·.:.'r; ::'.,: :..... ~.•'\".I.,,::,,! ......,••' •

<l.J
<l.J

o

o..r:::
D-\; .~ ~:. (~\_".:~ :\\.~;;,:;;

1.0

0.8

0.6

,~

:. '''!'''' .'-"" .\". ,".' ..,';" -. , .,.. ....
0.4

Binding energy in keV

0.2

Fig. I.
Photoelectron spectrum of
the surface made clean by following
methods:( a)
glass beads blust,( b ) rinse with distilled water after
cleaning with synthetic detergent,(c)supersonic cleaning in thetrichloroetylene.

211

3Kr---------------------------~

o : Oxigen• : Carbo n

<)

Iron

:

- ~ - -o2c

is 2K-

o

u

o

o

-

o

o

<)

c

-

Glass beads blust

U)

o

0

'

..

......

::J

c

-."

>.

~ 1KI--

-

<)

U
Q)

W

«

<)

•
<)

<)
<)

o

<)

U)

c

<)

O ~~I__~I_ _~I~J___L--I~I___IL--.--.L~~

abc

~

-e

•

de

f

g

h

Th e meth ods of th e clea ni ng

2c........• ___ Io-......... r>#r

2 o r-··'t-~-+_Im-+m_e-trs_e--1in....::g+in_t+r_ic+h e-+ne---l_~+-+----+---·"""-+·_-....j-I--_-t--~
_I

u

Q)

'.

Q)

-8

The cleaning effect by various
Fig. 2.
cleaning methods as follows:(a) glass beads blusting,(b) rinsing with distilled water,(c) immerse in solvent of trichloroetylene,(d) rinse with distilled water after
washing with synthetic detergent,(e) rinse with tap water after washingwith synthetic detergent,(f) supersonic cleaning in solvent oftrichloroetylene,(g) baking (200°C, 2 h) after thetreatment of (f),(h) Ar ionetching for 40 min after thetreatment of (g).

o

.£:

0...

o- -

-.

Supe rso ni c cleani ng
in t ri chi ene-t---t---r--+--+--+--If.-+---+--+--I---+-.--I-0.

. . .'..... : •• •.~···.--f-X 1/ 2.:~~+-+-~~~~,0~.....- •• •' .... .,.••••: . ..., ...... ...'"-.
Ri nse with dist illed water afterOl---+--I-- c leaning with synt het ic detergent+--+--+---+---+--I
I

291

I

I

I

I

I

I

I

I

288

I

285

282

Binding energy ( eV)Comparison of the heightFig. 3.
and shapes of carbon peaks from thesurface cleaned by different methods.

shape of the carbon peak originating from hydrocarbons on the surfaces are varied bymiscellaneous cleaning methods except by immersing samples in solvent as is shown in Fig. 3.
The height and shape of peaks after synthetic detergent solution cleaning is similar to thoseof supersonic cleaning. However, the sort of hydrocarbons remaining on the surface are not yet
iden tified.
As mentioned above, the effects of the cleaning are confirmed by the surface analysis.
However, it is recognized that cleaning agent used always remained slightly. In order to solve theproblem, we are thinking of applying composite procedures for surface cleaning.

212

N -25.

Preliminary Experiment on Discharge Cleaningof aSector Magnet Vacuum Chamber for the SSC

K. Ikegami, S. Nakajima, Y. Oikawa, Y. Ishibe,
H. Oyama, Y. Sakamoto, and S. Motonaga

A sector magnet of the SSC has a narrow gap. The vacuum chamber inserted into the gap
has low conductance compared with pumping speed at the valley. It is difficult to obtain the
aimed pressure of 3 '" 4 X 10- 6 Pa on the median plane because baking of the surfaces of themagnet vacuum chamber is practically impossible. High speed evacuation owing to degassing by
discharge cleaning becomes attractive. Because the magnetic field is produced inside the chamber,
ECR (electron cyclotron resonance) discharge cleaning method can be applied for this purpose.
We investigated the ECR discharge cleaning by the use of a model which has the conductance of
180 f,jsec, the surface area of 1 X 104 cm 2 and the pumping speed of 500 f /sec.
The experimental apparatus is schematically shown in Fig. 1. A vacuum chamber with 5 cm
height and 75 cm diameter made of stainless steel 304L is inserted between magnet poles thediameter of which is 72 cm. The cross section of the magnet as well as the field distribution isshown in Fig. 2. Microwave whose frequency and maximum power are 2.45 GHz and 800 W(CW) respectively is supplied via helix lancher. A double probe is used to measure the electron
temperature and the ion density of plasma produced for cleaning. A quadrupole mass analyser(QMA) is set near the pump head of a turbomolecular pump (500 €/sec) to observe the residual
gases, and another QMA is set after an oriffice (conductance = 0.6 .e/sec) to allow observation ofGAS-~~G QMA\d ~~~VACUUM CHAMBER

YOKE

COIL

MG

o
~

M. G : MICROWAVE GENERATORFREQUENCY :2.45 GHzJPOWER :

900

800 W CW MAX

POLE EDGE

I,G : ION GAUGE
H.V,G: HIGH VACUUM GAUGEI~ POLE CENT ER

QMA : QUADRUPOLE MASS ANALYSER
B,H : BAKING HEATERo : ORIFICE ( CONDUCTANCE: 0.5 LIS)
Fig. 1.
Schematic diagram of experimental
arrangement.

210

I

I

260

310

RAD IU S (

360

410

MM )

Fig. 2.
Electromagnet used andthe radial distribution of axial
magnetic field.

213

produced gases during discharge cleaning. Baking heaters are wound around the pumping ports toprevent adsorption of gases produced during discharge cleaning.
The cleaning plasma was produced at a hydrogen pressure of 3.7 X 10- 2 Pa. The vacuum
wall temperature increased from 25° to 80°C during about 6.5 h. The microwave power was
typically about 600 W. The plasma was not uniform in the chamber and the spatial distribution
depended upon the pressure and the magnetic field. Nevertheless the electron temperature of
10 < Te < 20 eV and the ion density of 3 X 109 < Ni < 1 X 10 10 cm- 3 were measured at theradius of 280 mm. Produced gases during cleaning were H20, CO, CH 4 , and CO 2 for virgin surface.
Temporal variation of the total pressure and the QMA signals are shown in Fig. 3 and Fig. 4,
respectively.
The ECR discharge cleaning is accomplished by wall surface impact of hydrogen atoms andchemical reaction between the wall surface impurities (oxygen and carbon) and hydrogen ions
I

I

I

I

I

I

I

I

I

I

I

I

I

ECR

~ I SCHARGE CLEAN I NG

I"

: 600 W
6,5 HOURS

POWER

~

--- VACUUM C8AMBER- - PUMP HEAD (500 Lis )-------===:;

OFF~

H2 ADNI TTEDBAKING

fN

I

o

I

?Fr

I

I

12

I

I

36

24

I

I

48

60

I

72

EVACUATED TIME ( HOURS)

Temporal variation of total pressure.

Fig. 3.

.2

~

ECR

Ql
~

o
0

0

r- DISCHARGE CLEANING

1

0
0

.:.

.

.

"

0

..

, ..

"

'~

, 0

"
. 0
~ .

..,

.. ..
""

-

0
0

.. Jl l(H2 ADM] TTED

rg~ BAK I NG

o

12

II

OFF
I

I

I :

24

.,

'"

...... .
: ..

4.

-

: 600 14, 6, 5 HOURS 0 I I:! H2°,.. 28 CO AND C H
2 444 CO')

0

",'.

>"

H2

15 CH 3

'"

o .

~

0 0
0 0 0

~; t • .a.

0"~., 0 ~ ••• •• t •
0 0

POWER

0

0

0

6-

)( 0

0 0 0 00)( "'Xi °r ..
F
"

(
1CJ

..

000

00

I

36

. ..

"

~

I

I

48

. I

I

00

I

60

EVACUATED T I ME ( HOURS )Fig. 4.

0..

Temporal variation of partial pressures.

I

72

0

i

214

and Franck-Condom neutrals from the plasma.1) We give here very rough estimation of the fluxes
by assuming that (1) ions hit the wall surfaces along the magnetic line of force (top and bottom
surface), (2) the neutrals hit uniformly all surfaces, (3) the plasma exists uniformly in the domainr ~ 68/2 = 34 em with the density and the electron temperature of 3 X 10 9 cm- 3 and 10 eV,
respectively and (4) ions have the thermal speed (2.5 X 10 5 em . sec-1 for proton at 300 K). The
calculation gives
ion flux cp.1 ~ 7.5 X 10 14 cm- 2·sec- 1
and neutral flux CPo ~ 6 X 10 14 cm- 2·sec- 1 .
On the other hand the pressure increases on the average by Lip = 6.7 X 10- 3 Pa due to the production of H 20 and so on. The amount Q of gas produced is given by Q = S~ SpLip, where Sp is
the pumping speed (500 f/sec) and T is the total cleaning time (6.5 h). The value of Q obtainedis 7.8 X 104 Pa·f""' 7.2 X 10 22 molecules. This means we transformed the surface impurities of
7.2 X 10 18 molecules/cm 2, into gases, that is to say, about 10 3 monolayers are treated by assuming
the surface roughness factor of unity. The final pressure obtained was 1.2 X 10- 6 Pa after
evacua ting 78 h.
Model study on ECR discharge cleaning of the vacuum chamber inserted in the magnet was
carried out by using H2 gas pressure of 3.7 X 10- 2 Pa and 2.45 GHz microwave of 600 W.
A hydrogen plasma, whose density and electron temperature were 3 X 109 < Ni < 1 X 10 10 cm- 3
and 10 < Te < 20 eV respectively, transformed the impurities (C and 0) into H 20, CO, CH4 , andCO 2, About 10 3 monolayers near the surface were cleaned down. We obtained the final pressureof 1.2 X 10 - 6 Pa after evacuating 78 h.

Reference
1)

Y. Sakamoto, Y. Ishibe, K. Yano, H. Ohyama, Y. Tanaka, N. Fujisawa, Y. Matsuzaki,
N. Suzuki, K. Maeno, T. Yamamoto, and K. Yokokura: J. Nucl. Mater., 93'94, 333 (1980).

215

N -26.

Beam Diagnostic System for the RIKEN

sseY. Yano, N. Kishida, A. Goto, and N. Nakanishi

In the RIKEN accelerator complex system, a beam preaccelerated by the injector istransported to the SSC through the injection beam transport system and then is accelerated by
the sse. The high-energy beam extracted from the sse is transported to an experimental setup
through the beam handling system. In such beam transportation and acceleration, parameters forthe relevant beam handling elements should be optimized on the basis of beam properties observed
at strategetic locations with various kinds of beam diagnostic apparatus. We have determined thearrangement of these apparatus, considering necessary procedures for adjusting the beam handlingdevices.
Figure I shows the beam diagnostic system for the sse. With the aid of this system, eachelement of the sse is tuned up as follows: We optimize the parameters (position, current andvoltage) for the beam injection elements (BMI, MIC2, MICI and EIC), measuring the beam
trajectory with the slit system (SIO - S13) as well as the main differential probes (MDPI and
MDP2). The MDPI is equipped with the Fork probe (FK) by which beam bunch length ismeasured. This type of probe has been developed at GANIL and is successfully used. From thebunch length measured with the FK, the voltage for the buncher on the injection beam transportline is adjusted so as to give the minimum bunch length at injection point. By means of the FK,
we can also observe the variation of bunch length of accelerated beam inside the sse. One of thefeatures of our beam diagnostic system is that the emittance measuring device (EM 1) is installedat the injection point. Because the fringe magnetic field from the sector magnets (SM) exists at
this area, the emittance is calculated on the basis of the magnetic field data as well as the beam

Fig. 1.

The arrangement of beam diagnostic devices in the sse.

216

current data from the EM 1. It can easily be done by using the above emittance measuring device
to match the beam emittance in six-dimensional phase space with the desired one. In one of thevacuum chambers, twenty pairs of phase probes (PP) of capacitive pickup type are arranged
radially. These probes observe the phase history of accelerated beam in a non-destructive manner.
From the measured phase history, the currents of main coils and trim coils of the sector magnets
are optimized so as to produce the isochronous magnetic field. The orbit center of acceleration
orbit is measured by three main differential probes (MDP1 - MDP3). We can obtain the twodimensional position of the orbit center. By observing the behavior of movement of the orbit
center in the injection region, the voltage of the EIC and the currents of injection harmonic coils
are adjusted so that the orbit center may move to the machine center. The harmonic field is also
applied in the extraction region to increase the turn separation and accordingly improve theextraction efficiency. The movement of the orbit center in the extraction region is observed
again by the MDP system and the currents of extraction harmonic coils are adjusted. The parameters for the beam extraction elements (EDC, MDC1, MDC2, EBMI, and EBM2) are optimizedin the same manner as in the injection case by measuring the beam trajectory with the slit system(SEO - SE4), the MDP system and the extraction radial probe (ERP).
The theoretical study of the adjusting procedures mentioned above is now in progress.

217

N -27.

Model Test of 1 / 5 Scale Movable Box TypeRF Resonator for the RIKEN

sseK. Ogiwara, T. Fujisawa, and Y. Oikawa

A resonator whose resonant frequency is varied from l7 to 45 MHz with the use of movable
box in the resonator is designed for the RIKEN SSC.l) The transmission line approximation isused in the calculation for the resonator shown in Fig. 1. Based on the calculation, a 1/5 model
resonator was constructed and the resonant frequencies, Q-values and radial distributions of RF
electric field at the accelerating gap were measured. The resonant frequencies and Q-values
measured are shown in Fig. 2 together with the calculated values. The resonant frequencies
measured are fairly well reproduced by the calculation. However, the measured Q-values are about
those of 0.4 times the calculated ones .. The poor agreement between the measured and calculated
Q-values may be due to poor contact between the movable box and the outer wall and to thecomplex structure of this resonator.

Io Fr eq uency

8

8

50

N

A- A Cr oss sect ion

2 X 10 4

x Q-Value

40

I

L
>c

u

(])

(])

30

~

:J
0-

<U

~

~
<U
C

1 X 10 4

~

a

20

0
(/)
(])

x

0:::

)(

X

10

I, , , , I I

o

I

I

,

I

1000

Distance fr om end of resona tor
to movable box (m )8 - 8 Cros s section

Schematic view of the movable
Fig. 1.
box type resonator.

Fig. 2.

Resonant frequencies(f) andQ-values measured( 0 and ,x) andcalculated (-) by the transmission line
approximation.

Relative distributions of RF electric field along the dee edge of the model resonator were
measured by perturbation method. 2) The measured distributions are shown in Fig. 3, where thedee voltages are normalized at injection radius. The strength of the field at middle radius is 75 %of that at the injection radius for 45.9 MHz. This is not desirable for beam acceleration. In order218

Parame ter= RF Freque ncy ( MH z)

llf

1. 0

17 MHz~~-----

0.9
250

1 .1~ M HZ

1.0 ~o~~"- D e e Volt age estimated -+--/-A1/-'+-----1
200 - with 300 kW inpu t --+--.,,£/I-Il----j/~---1
./' I
I
180
I
/
/'
160

0.9
1.2[

wLo - __~:

~L-'e___.
30 MHz40 MH z

Q)

Q)

bD

. 2:
Ct:

p

",.

1.0

",

......

0.8...... .....

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

.'"
""

2

/

/

/

I

/

/

/

I

/

/

1//

/

/

/

/

/

/

/

80

0

70

14

60

45 MH z
1.2

50

1. 0
/
;
",.

0.8

I

>
Q)
Q)

",

/

F / /

100
90

0

/

' /

/

V / /

~

1. 2

Q)

/

II

:; 120

>
Q)
Q)

S1

r / /

/

-e _____ - -

(5

u

/

140

_,..~""

tl.()

..3

I
I

.......

......

.............----_... ".., '"

'"

'"

'"

......

f-,: / / /~~jf--~ ,
40

/ /

j.

.!:.'
'~"'{"

'"

W~
'"'"

20

Position along accelerating gap

Relative distributions of RF
Fig. 3.
electric field along the accelerating

Harm onic number r-h=9

()

I

15

/

:::

25
35 40
30
RF-Frequ ency ( MH z)

45

Dee voltage required for beam
Fig. 4.
acceleration.

gap for the 1/5 model resonator.
Solid lines show the values after
the modification.
to improve the distributions, the stem were modified as shown in Fig. 1 (hatched). The electricfield distributions are improved by the modifications as shown in Fig. 3. The dee voltages
required for beam acceleration have been calculated for several particles,3) which are shown in
Fig. 4 as function of RF-frequency. The maximum output power of the amplifier for the
resonator is to be 300 kW. The dee voltages generated by the present amplifier are estimatedusing the measured and calculated Q-values. T~e results are also shown in Fig. 4. The estimateddee voltages are sufficient for the beam acceleration.

References
1)
2)
3)

T. Fujisawa: RIKEN Accel. Progr. Rep., 12, 196 (1981).
L.C. Maier, Jr. and J.C. Slater: J. Appl. Phys., 23, 68 (1952).
A. Goto: RIKEN sse Engineering Note, OA- 10 (1982).

219

N -28.

Effect of Resonance on the Beam in the RIKEN

sseN. Nakanishi, Y. Yano, and A. Goto

Recently, measurement was carried out for magnetic fields in the system of two full-scale
sector magnets, and beam dynamical properties of the RIKEN separated sector cyclotron havebeen recalculated by using the measured data. As one of properties, focusing frequencies fortypical particles and energies were examined, and it was confirmed that the results are not so
different from those which had been obtained using magnetic fields in model magnets.
According to the calculation, a 9 MeV proton beam crosses the resonance line vr - 2v z == 0 in
a (vr ' vz) space during acceleration. The focusing frequency is shown in Fig. l. This resonance is
known to be a quadratic non-linear coupling resonance and arises from the existance of thesecond-order derivatives of the magnetic field distribution. It is seen that the beam encounters theresonance at the betatron frequencies of vr = l.3 and V z = 0 .65 (E = 144 MeV, R = 295 cm).
0.9 1.0

1. I

HI +

0.8
9 . 00

MEV

N

w

0.7

::l

Z

0.6

-

-

I

o . 5 .r: ~ - - - - - - - - - - - - - - - - - - - - - - - - -:- - - - - - - - - -Fig. 1

Focusing frequency

of a 9 MeV proton beam.

We have only the data of the axial component of magnetic induction Bz (r, e) on the medianplane, that is of B(r, e, Z = 0) = Bz(r, e). The field B(r, e, z) off the median plane is obtained in a
power expansion in z using symmerty with respect to the median plane: 1)
I

Bz = B + 2

z2 . f2'

where
f2 =- {

a 2B
+
ar2

laB
rar

+

1 a 2Br 2 a 8 2 } z = O.

From rot B = 0, radial and azimuthal components of the magnetic field are given as
aB
1
Br = z - - + - z3 . far
6
3r . Be = z

aBae+ 6 z3. g3 '

220

where
f3 =

_a_ f=_{~+
ar

ar 3

2

la 2B

laB

rar2

r2 ar

I a 2B
raraO

+

+

la 3B

2a 2 Br2 ara0 2

r3 a 02} z =0

and
a 3B

a

-'
+
g3 = ao f2 = -{ ar2 aO

1 a 3Br 2a0 3 } z = O.

Calculation has been done by modifying the program ACCELP.2) Figures 2(a) and (b) show
the radial and axial oscillations of particles arround the central orbit during acceleration. In order
to examine the effect of the higher-order terms on amplitudes, two particles of initial amplitude
5 mm in each direction were traced using equations without (case a) and with (case b) the higher
order terms. The accelerating voltage was assumed to be 250 kY. We could not find any
remarkable difference in amplitude between them. These initial amplitudes correspond to theemmitances of around 30 and 20 mm· mrad. respectively, and these are probable values in practice.
Thus the influence of the resonance on amplitudes is practically negligibly small.

9.0

MEV P

1 ·0
~

~ o. 0 -H-----¥-f--+--l-H-H.f++I-H-!+W
0:::
o
- 1.0
1 .0
:>::

~ o. 0 +t++-t+H1-1+
No- 1. 0I .0-~:: o· 0 -H-----¥-+-+++++++l++H+1+
0:::

o

-1 .0

1 .0
:>::

~ 0 . 0 +t++-t+H1+t+ttftr
N

o
- 1.0

1100

I

200

I

I

300

I

R I CI1 J

I

400

Fig. 2.
Calculated oscillation patterns
around the central orbit during acceleration.
Calculation was done without (a) andwith (b) the higher-order terms.

In order to observe clearly the effect of the higher-order terms, calculation has been done
for a beam with a large axial amplitude in the accelerating voltage of 60 kY. The axial oscillations
are shown in Fig. 3. As seen in the lower drawing in Fig. 3 , it is observed that amplitude grows
up in the case b.
In order to make the resonance effect small it may be required that the injected beam is ofgood quality and that the energy gain per turn is made as large as possible.

221

1.0

I

'8u
'-'

!

1

0.0

N

0

I
I

1
I
I

I

- 1. a

I

,I

1

'

,1

'I

1.0

8

u

0.0

N

o

-1. 0

100

300

200

400

R(cm)

Fig. 3.

Axial oscillation patterns in the case of a large

initial amplitude. Calculations were done without(upper)
and with (lower) the higher-order terms.

References
1)
2)

J. P. Blaser and H. A. Willax: IEEE Trans., NS-13, 194 (1966).

N. Nakanishi: Reports I.P.C.R., (in Japanese),TI., 189 (1981).

222

N -29.

sse Beam Handling System
T. Inamura and N. Kishida

The revised plan view of the sse beam handling system is shown in Fig. 1. The previously
reported design 1) has been modified to provide more target areas. The revised system transports
the beam from the sse to eight main target areas. The beam reaches six target areas after passing
two standarized 90° -bending magnets, which are placed in mirror or antimirror symmetry. The
target area T 7 is arranged so that a crossed-beam experiment could be made using the beams froman AVF injector cyclotron and from the sse.
Numerical calculations of the ion optics have been carried out to second order using thecomputer code "TRANSPORT".2)
The present system provides the following beam preparation modes:(1) Achromatic, double-telescopic transport to every target area;(2) Double-dispensive, double-telescopic transport with a momentum resolution up to 20000
in lab. 2, 3, and 6;(3) Isochronous, nondispensive, double-telescopic transport with a time resolution less than
500 ps in lab. 4 and 6.
It should also be stated that even in mode (1) or (3) the momentum resolution becomes
about 10000. By taking into account the second-order aberration, the momentum resolution was
estimated for a beam whose maximum divergence is 2.432 mrad at the object point So; the slit

Lab.S

o

5m

u....L..L.LJ

Lab.4

Fig. 1.
Plan view of the beam handling system
for the RIKEN sse. So is the object point of
the system.

223

width at S.o is 1.0 mm. In this connection, the first-order momentum resolution is 23000.
We assumed at the moment that the entrance and exit pole faces of the bending magnets
are flat and the fringing field boundaries are given by an unc1amped Rogowski field. If the curved
pole faces are adopted, the principal second-order aberration can be minimized to result in muchhigher momentum resolution.

References
1)
2)

T. Inamura, N. Kishjda, H. Saito, and M. Watanabe: Sci. Papers I.P.C.R., 75, 236 (1981);
T. Inamura, N. Kishida, and H. Saito: RIKEN Accel. Progr. Rep., 12,203 (1981).
K.L. Brown, F. Rothacker, D.C. Carey, and Ch. Iselin: SLAC Report, p. 91 (1974).

224

W30.

Biological and Physical Irradiation Beam Channel
for theRIKEN SSC

N. Kishida, S. Kohmoto, A. Goto,
E. Takenaka, * and H. Kamitsubo
Biological and physical irradiation at the RIKEN sse facility aims at development of heavy-ion irradiation
technique, basic study of biological effect induced by heavy-ion irradiation, and preliminary stuc,ly of physicalirradiation by heavy-ions. Transportation of various kinds of heavy-ions to irradiation areas and easy adjustmentof irradiation conditions are required for the biological and physical irradiation channel.
It is desired that the irradiation spot size is continuously variable from 1 '" 2 mm squares for a spot scanning
irradiation to 20 cm squares for an overall irradiation. It is also desired that the irradiation channel has bothhorizontal and vertical irradiation beam-channels which are shielded from each other by thick concrete walls.
The biological and physical irradiation room is to be located in the eastern end of the sse experimental
halls, and the area inside the shielding walls is 7.5 m X 22 m square (Fig. 1). Figure 2 shows a cross sectionalview of the beam transport system to each irradiation room. Figure 3 shows a plan view of radioactive
isotope (RI) beam production channel which is installed on the same level as the horizontal irradiation beamchannel.
The beam extracted from the sse is transported to point T 5 so as to become an achromatic beam which isused as an initial beam in ion-optical calculation of the irradiation beam transport system.
Biological andphysica l irradiat ion
laboratory
Nuclear structure

From Heavy- Ion I inac

Biologicalandphysical
irradiationlaboratory

o

5m

~

sse vaul t

T4
Nucluar reaction laboratory

Atomic physics
laboratory

Fig. 1.
Beam transport system and layout of experimental and irradiation areas
with the sse. The biological and physical irradiation laboratory is located in thetarget area T 5 which is at the eastern end of the sse experimental halls.

* Faculty of Medicine, University of Tokyo.

225

Horizontal
irradiationlabr ato ry
II~ f ~ Qv

, d"latlon la boratory
I
Vertical Irra

I

I
Table 1.

Fig. 2.

o
I

4 5m
I

I

Cross sectional view of thebeam transport system in the biologicaland physical irradiation laboratory.

Positron emitting nucleides produced by the SSC beam.

Nucleide
l1C

Reaction
12

HC)

eN,

20.34 m4

1~)

9.96 m150

e6t:>,

150)

123 s

18F

e9p,

18F)

109.7 ml~eetNe , l'>Ne)

17.4 s

1~

(

C,

23Mg

e Mg, 2\1g)

27Si

eSsi,

27Si)

4.14 s

30p

elp,

3Op)

2.50m

(32s,

31S)

2.72 s

31S

4EnergyHalf life

Larger than
100 MeV/u12.1 s)Less than
100 MeV/u

In the horizontal irradiation target area the beam spot size is variable by a triple quadrupole magnet (QH)from 2 mm X 2 mm to 20 em X 20 cm. The achromatic beam is transported to the vertical irradiation room
using two bending magnets, four single quadrupole magnets and one triple quadrupole magnet. The quadrupole
magnet Qy controls the beam size from 1 mm X I mm to 10 cm X 10 cm.
It is required to know the accurate position irradiated, especially in the case of irradiating deep internalorgans using heavy-ion beams. High energy heavy-ions induce nuclear reactions in the organs and produce
radioisotopes which emit positrons. If necessary the accurate stopping position of the radioisotopes which areproduced by the nuclear reactions can be determined by positron computed tomography (PCT). If secondly RI
beams can be utilized, those will be very valuable not only for the biological and physical irradiation but also
for the study in many other fields. For these purposes a production and transport system of RI beams isdesigned.
Positron emitting nuclides with a short half-life time which can be produced by the SSC beam and used
for the irradiation are listed in Table I.
Target for producing a secondly RI beam is installed at point T 5' and the slit S excludes background beams
which are dispersing by the bending magnet BE2 (Fig. 3). The primary beam passing through the target without
a nuclear reaction is introduced into a beam dump.
We will, as an example, try to estimate beam strength of lIC ions which are generated by the 12C( 1~, BC )IJc
reaction at an incident energy of 130 Me V lu using this system. The required RI beam transport system is such0000that it will collect the ions which are emitted from the target within 5.0 ± 0.5 and 0.0 ± 0.5 in horizontal
and vertical directions, respectively, and ± 1 % in momentum spread. The target thickness 1 g/cm 2 is thus
determined: the energy loss difference between the ions in the target may not exceed the momentum
acceptance of the transport system. If 1~6+ ions of 1 pJ..LA (one particle mircro ampare) impinge on the target
and if the differential cross section of the reaction is estimated at 454.1 mrad/sr, 4 X 10 7 ions of l1C 6 + will be

226

Fig. 3.
Plan view of RI beam
production and transport channel (Allof the magnets but B 1 belonging to thevertical irradiation system are omitted
in this figure.). The target for producing
secondly beam is installed at T s. S isa beam slit for excluding backgroundbeams.

BE 1
S : Slit/
BE Bend ing Magnet L/
30
QT Quadrupole Tri plet V .
T1 Targe to 1 2 345m
0

I

!

I

!

I

!

1

!

! ,

I

RADIOACTIVE BEAM COURSESINGLE RRY
I:

y=O.OO MM. OY=O.OO MR. OP=4.00%

X=2.00 MM. OX=8.73 MR.

w

.;,

r::
II)

0
0

.,;

0
II)

II)

0>

II)

- -

CD
CD

CD

N

<r-

Lt)

W

I-

CD

W

al

I-

al

..;
.;

c:i

-;

N
I

I

r::
I

0

.,

0

II)

0

'"

-

0

0

II)

II)

0

0
0

0

0

II>

...

...

0

0

'"

II)

...
CD

'"
0

I ...'"
0

0

a:

::>
0

I

a:

::>

<>

'"

Fig. 4.
Ray trace of five ions with a central momentum and other five ions with
momentum larger by 4 % than the former in the RI beam transport system. Twoarrows at S denote each beam size.

obtained every second.
Traces of a single ray are shown in Fig. 4. It is found that the ions dispersed by the bending magnet BE2
can be analyzed by slit S, where the ions do not focus.
More detailed discussion of this work has been published in Ref. 1.

Reference
1)

N. Kishida, S. Kohmoto, A. Goto, E. Takenaka, and H. Kamitsubo: Reports I.P.C.R., (in Japanese),58, 77 (1982).

227

N -31 .

Calculation of RF Electromagnetic Field
by Finite Element Method (II)M. Hara, T. Wada, T. Fukasawa, and F. Kikuchi

Efforts are continued to develop computer codes to calculate electromagnetic fields in the cavities basedon finite element method. We have already developed two computer codes H2DB and HAX 1) which are used fora resonator with constant cross section and for an axisymmetric resonator. We improved these and related codes.
At the same time we developed arbitrary three dimensional calculation program to solve Maxwell's equations using
penalty method.
(1) Improvement
We have added new functions to H2DB and HAX codes. One of them is a restart function. The calculation
which is terminated by time limit can be restarted any number of times using the previous results from disk fi.1e.
We have developed a bandwidth minimization code in order to save memory size and computing time, introducing
a connection table. 2) Minimization procedure is useful especially for complicated shape of cavity. The code
MESH2D is also improved in numbering the nodal points to minimize the bandwidth. It is necessary to findboundary for field plotting and power loss calculation. We use also connection table to find it, which extremely
reduces computing time.
(2) Three dimensional calculation code (MAX3D)
In the case of a resonator with constant cross section or an axisymmetric field, many works have been donewith satisfactory results. 1),3) But actually we have many problems that are hard to treat with two dimensional
calculations, and true three dimensional calculations are strongly required. In general three dimensional case, only
a few papers have been published. 4) It is no more useful to use only one unknown variable such as a scalarpotential. It is convenient to take electric field E = (Ex, Ey , EJ as unknown variables because of the easy treatmentof boundary conditions and easy understanding of physical meaning. In this case, we must take care of thecondition div E = O.
We deal with the time-harmonic propagation of electromagnetic waves in a vacuum of bounded space nsurrounded by perfect conductor. Eliminating H, Maxwell's equations are written as
rot rotE - A E = 0, divE = 0 (in n),(1)

where A = W 2€J.l , € and J.l are dielectric constant and magnetic permeability in a vacuum. Boundary conditions
aren X E = 0 (on r),(2)

where n denotes the outward normal on the boundary r. This is an eigenvalue problem for three componentsof electric field E. Restriction of div E = 0 is to be imposed in order to exclude undesired solutions. Penalty
method is a convenient way to impose such a restriction. 4) We take a weak formulation:f n (rotE, rotoE)dV + s Sn (divE, divoE)dV = Sn (E,oE)dV,
A(3)

where s is a penalty parameter. Euler's equation is obtained from Eqn. (3) as
rot rotE - s grad divE = A E .

(4)

In this case, div E = 0 and rot E = 0 are satisfied when A = O. For positive A, the solutions of Eqn. (1) arealways those of Eqn. (4). Equations (4) may have other solutions than those of Eqn. (l). So far as the228

the parameter s is set to be large in some degree, such a mixture can be avoided for lower modes. Divergencefree condition can be checked by evaluating the following equations:

div

(5)

In the present study, four noded tetrahederal elements are used and Ex, Ey , and E z are approximated withthe first-order test functions. In order to impose boundary conditions, Euler's angles are used, if necessary, todetermine the normal direction and to rotate the axes at each surface point. Jennings method is used to solve
the generalized eigenvalue problem Ax = A. Bx for real symmetric band matrices. 5) First we made calculation fora rectangular cavity resonator. Parameter s is set to 1 and the smallest five eigenvalues are calculated. In thiscase, unphysical solutions are not found below the fifth mode. Next we made calculation for a cylinder cavity
and the example is shown in Fig. 1. In this case, unphysical solutions are mixed for certain region of s values.
It is found that these solutions do not satisfy the condition of div E = O. Parameter s-dependence of eigenvalues
are shown in Fig. 2. It can be seen that the s-dependence is small for physical solutions.

10 i'--_+_----\
y

10

x

z=O

z =1.67z=3.33

z=5.0

(b )

(d )

Calculations for 1/4 cylinder of 10 in height and 10 in radial length.
Fig. 1.
At two planes of x = 0 and y = 0, mirror symmetry boundary conditions are
imposed. Penalty parameter s is set to 1. Results are shown by contour plotsof Ex' E y , and Ez at z = constant planes.
(a)Schematic view of 1/4 cylindrical cavity ,

(b)
(c)
(d)

Contour plot for TMolO mode ,Contour plot for TE211 mode .
Contour plot for TM 210 mode .

Furthermore, we made some calculation deforming these rectangular and cylindrical cavities slightly andsmoothly. Obtained results are consistent with the perturbation theory as far as the deformation is small. Whenthe deformation is large, however, the condition div E = 0 does not become fully satisfied because of theroughness of mesh size and the slow convergence of solution. In the present calculation, number of the nodal
points is limited to be less than 1000 because of the memory size of the computer, which means about ten
nodes in each direction. For very complicated boundary shape, errors become large because mesh size is coarse
and therefore the condition div E = 0 is not fully satisfied. But this difficulty will be overcome with increasing
available memory size.

229

0.3

0.2

7

/

/

/

/'

TM 210
TM2l1

c.n
(l)
~

m

>

c

(l)

tlD

W 0.1

TM olO

0.05
0.5

1.0
s

1.5

Fig. 2.
Penalty parameter dependenceof eigenvalues for 1/4 cylindrical cavity.
Varying s-parameter from 0.5 to 1.5,
we calculated five modes for each s.
Among these solutions, only threemodes are physically allowed. Physicallyallowed modes have little s-dependence
and satisfy the condition div E = o.

References
1)
2)
3)
4)
5)

M. Hara, T. Wada, A. Toyama, and F. Kikuchi: Sci. Papers I.P.C.R., 75, 143 (1981).
E. Cuthill and J. Mckee: Proc. 24th Nat. Conf. Assoc. Comput. Math., ACM Publ., p. 69, 1122 Ave. of
the Americas, New York, N.Y. (1969).
K. Halbach and R. Holsinger: Particle Accelerators,L 213 (1976).
R. Leis: Math. Zeitschr., 106, 213 (1968); R. Hoppe: Numer. Math., 36, 389 (1981).
F ACOM FORTRAN Scientific Subroutine Library SSL-II User's Guide.

230

N -320Status Report of the Prototype Baby Cyclotron

T. Karasawa, N. Hayashi,* and T. Nozaki

Early in the year, 3He++ ions were accelerated to 13 MeV with the dee voltage below 20 kV
and the frequency of 38 MHz by second harmonic mode. We applied this experience to 3He
acceleration at the 168-type Baby Cyclotron at the Muroran Plant of JSW, which will be used for
activation analysis of semiconductors.
In this year, over three hundred cases were submitted to diagnosis by the brain imaging withpositron ECT (emission computed tomography) after respiratory injection of 11C02 gas and/or
oral injection of 11C-Iabeled glucose produced by photo-synthesis.
Some troubles of the cyclotron happened: (1) in February, a small amount of oil for the
deflector cooling rushed out into the vacuum chamber ; (2) electric insulation of the magnet coil
was damaged because of miss operation done without water cooling ; (3 ) about 30.e of waterleaked out into the vacuum chamber from a tube for ion source cooling in December.
ECT imaging of positron emitters utilizes the annihilation coincidence detection , theannihilation occuring at the end of the positron range. Thus, the positron range is naturally
smaller than the spatial resolution of ECT instrument itself. The range of positrons emitted fromHC, 13N, 150, and 18F in Mylar and Al foils have been measured by a 21r gas flow counter(Geiger-Miiller region). The results are shown in Fig. 1, and the 1/10 thicknesses are tabulatedwith the maximum positron energies.

.----.-----'----<>- :

lIe

-6-

:

13 N

-0-

:

--<>- :

150
IS F

.c
>

"..=;

u

«

10 - 1 ~--~--~----~--~---=~--~--~~~----~--~

o

50

150

200

250

300

350

400

450

500

Thickn ess of AI ( mg/ cm 2 )Fig. 1.

Absorption curve of positron in AI.

Table l. 1/10 thickness of positrons.
NuclideMylar(g/cm 2 )Al
(g/cm 2 )E (MeV)

0.120

0.131

0.97

0.169

0.170

1.19

0.346

1.74

0.077

0.635

0.073
* Takeda Chemical Industries, Ltd.

231

Fig. 2CD

Target box , Q)

Q)
@
G)

Beam of deuterons ,Needle valve for flow rate control ,Transmission tube (1/8" dia. and10 m long) ,®
(J)

Ionization chamber,
Diagnosis room ,®

Pressure gauge.

N 2gas cylinder ,Flow diagram of continuous gas flow system for 150 production.

80
70

C 40
ro

>

o
~ 30

0:::

20

200

20

500

S ( ml / mi.n )Recovery yield vs. flow rate 150 production at
Fig. 3.
continuous flow.
At present, the spatial resolution of the positron ECT is about 10 mm, while the 1/10
thicknesses of positrons emitted from HC, 13N, 150, and 18F are below 4 mm in water as shownin the Table 1. We may conclude that the spatial resolution of the positron ECT is not degradedby the positron range for positrons emitted from those nuclei.
The target gas of nitrogen under bombardment by deuterons is continuously swept out of thetarget box and transported to diagnosis room. The flow diagram is shown in Fig. 2. Target
volume and pressure, and sweep gas flow rate affect recovery yield at the diagnosis room. An
example of the yield vs. the flow rate is shown in Fig. 3.
In Fig. 3 , the yield has a maximum at the flow rate of sm' In the region of s < sm' theyield increases exponentially with the flow rate due to the decrease of the decay in transit fromthe target box to the diagnosis room. In the region of s > sm ,the yield decreases gradually withthe flow rate. It is caused by the shortening of irradiation time. For a closed target irradiation,
the yield C(mCi) during the time t(sec.) is expressed by the following equation,2)
C = Col { 1- exp (-Xt) } ,(1)

where Co (mCi/ J1A) is the saturation activity per beam current, 1(J1A) is the beam current and X isthe decay constant. When Xt is small, Eqn.( I) is approximately equal to C = Co IXt.

232

For a continuous flow, the equation for the recovery yield is as follows:(2)

where Va is the nominal volume of the transmission tube from the target box to the diagnosis
room, s is the flow rate and Va/s is the transit time. V t and Pt are the volume and pressure of thetarget box, respectively. We are going to check Eqn.(2) experimentally.
An apparatus for automatic synthesis of methionine l1C from homocystein thiolactone andl1CH} has been set up. A schematic diagram of its main part is shown in Fig. 4. There, Block A
is a source of distilled water and organic solvents, Block B is the portion for the introduction of
the product into a syringe through a millipore-filter, and Block C consists of a waste reservoir anda source of reduced pressure. Beside these, a box is attached with tubes for supplying liquidsof desired temperatures and for pressure addition and evacuation.
Methionine- l1 C is synthesized in Reaction Flask in Fig. 4 and separated by liquid
chromatography to give final product ready for intravenous injection. The entire process iscompleted in 15 min. The yield is 80 %, when l1CH31 is introduced into the apparatus with lessthan 3 me of an innert gas. Some efforts are needed to concentrate l1CH3I in such a small amountof gas.
From
Mel / N2 line

(To Block A)
High pressure
HPLC column
To HPLCrem 0 te val ve ,cEpzzZZZ222ZZZZ2:z2§P---- de t ect 0 roActivatedcarbon trap

Off~

From HPLC
detector
Soda lime
filterFraction
recei verTo exhaust
Open
Injection
receiver(To block C)

Fig. 4.

Supply(To block C) HPLCpump

(To block B )Automatic methylation apparatus.

References
I)

N. Feather: Proc. Chambridge Phil. Soc., 34, 599 (1938); L.E. Glendenin: Nucleonics, Jan.,p. 12 (1948).

2)

J.C. Clark, and P.D. Buckingham: "Short-lived Radioactive Gases for Clinical Use",
Butterworth, London, p. 323 (1975).

233

V.

RADIATION MONITORING

1.

Routine Monitoring of the Cyclotron

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

Results of routine radiation monitoring carried out on the cyclotron from April 1981 toMarch 1982 are described.
No remarkable change in leakage radiation and residual activities was observed during thisperiod. Some aspects of the leakage radiation are described in the following report.
(1) Surface and air contamination
The surface contamination has been kept below 10-5 J.lCi/cm 2 on the floor of cyclotron room,
the underground passage and hot laboratory, and below 10- 6 J.lCi/cm 2 in the experimental areas andchemical laboratories. The radioactive nuclides found by the 'Y-ray spectrometry were 22Na, 58Co,
60Co, 65Zn, 75Se, 183Re, 1850s, and 137Cs. The contamination was wiped off twice a year, andimmediately after this decontamination, the contamination on the floor of the above places had
been reduced to a value below 10- 7 J.lCi/cm 2.
When radioactive substances were handled in the hot laboratory and chemical laboratories,
slight contamination of the air in the draft chamber was observed. The air in the draft chamber
was discharged through the exhaust, and the value of radioactivity concentration in the exit was

Table 1. Annual exposure dose received by the cyclotron workers
from April 1981 to March 1982.
Number of persons
Workers

Operators
Nuclear physi,cists
Accelerator physicists
Physicists in other fields
Nuclear chemists
Radiation chemists
Biological chemists
Health physicists
Total

Collective

Dose

10 - 100> 100undetectable(mrem)(mrem)

3

5
3
3
3

6

15
25
3
2
8
5

6

67

20

Average annual dose per person: 11.7 mrem
Maximum individual annual dose: 180 mrem

Total

dose
(man-mrem)

2

8
9
18
28
11

180
30
40
90
700

2

2
8
5
89

1040

234

below 10- 12 IlCi/cm 3 . The quantity of activities on the glass fiber filter in the exhaust was
10- 2 - 10-4 Il Ci /l OO cm 2 , and the radioactive nuclides were 76Br and 117mSn.
(2) Drainage
The radioactive concentration of the drain water from the cyclotron building was found to
be of the order of 10- 7 IlCi/cm 3 . The total quantity of activities in the aqueous effluents in thisperiod was about 3 IlCi, and the radioactive nuclide found by the ')'-ray spectrometry was mainly
60Co.
(3) Personnel monitoring
The external exposure dose to personnel was measured with 'Y-ray and neutron film badges.
The dose received during the present period by all the cyclotron workers is shown in Table l.
The collective ,),-ray dose to all workers was 1040 man-mrem, while the collective dose owing tothermal and fast neutron exposures were too small to be detected. The collective dose to thecyclotron workers is about 55 % of the value in the preceding period.
In this period the average annual dose per person was 11.7 mrem, and the maximum
individual annual dose was 180 mrem.

235

V -2.

Leakage-Radiation Measurement at the Underground
Passage of the Cyclotron Building

I. Sakamoto and S. Fujita

Leakage radiation during operation of the cyclotron at the underground passage of thecyclotron building was measured. Leakage dose received from April 1981 to March 1982 by 'Y-ray
and neutron film badges which were left at the underground passage, are shown in Table 1. No
machine time was allotted for deuteron acceleration in this period.
Table 1. Leakage radiation dose (in mrem) at the undergroundpassage of the cyclotron building from April 1981 toMarch 1982.

1

2

1340
380
90
1810

0
0
40
40

Radiation'Y-rays (mrem)
Thermal neutrons (mrem)
Fast neutrons (mrem)
Total (mrem)* See the figure shown below.
I

I I I I I

o 1234 5m

Experimental area (L) :I
I
I
I

Undergroundpassage

I

I

Undergroundpassage~
Target ~~4---I-----"'"

:I t

[

I

'l:/T

UP

x1

I

UP

o

Hand foot cloth
monitorControl room

Basement
Ground plan

236

As to the dose values at point No. 1 measured every month, the maximum total dose of
430 mrem was observed in July. In this case, the values of gamma dose and thermal neutron
dose were 340 mrem and 90 mrem, respectively.
The fast neutron dose observed at point No.1 in October was larger than those in othermonths. The values of thermal neutron dose and fast neutron dose were 40 mrem and 70 mrem.
As a result of investigation, it was concluded that the increase of the neutron dose was mainly due
to 3He-particle activation analysis for surface oxygen on silicon, aluminum, tin and zinc in the
beam course No.2 carried out in October. Moreover, in this month, about 2 mCi of radioisotopes
were produced by 59CoeHe, n) 61 Cu and 75As(a, 2n)77Br reactions in the beam course No.1 and
No.2.

237

V -3.

leakage X-Ray Measurement on TANDETRON

I. Usuba, Y. Sasa, M. Uda, and H. Sakairi

X-ray monitoring was carried out on TANDETRON for the acceleration of Si and Au ions.
Areal intensity distributions of leakage X-rays at I m above the ground were measured with an
ionization chamber survey meter for X-rays and -y-rays (27 keV '"'-' 2 MeV).
(1) Acceleration of Si ions
Si ions were accelerated on the operation condition that current intensity of injected Si- ionsis 9 IlA and terminal voltage is 0.5 MV. In this case energies of accelerated Si2+, Si 3+, and Si 4+
ions were 2.4 MeV, 3.2 MeV, and 4.0 MeV, respectively and the currents were 2 J.1A, 0.8 IlA , and0.25 J.1A, respectively. Current of Si+ ions could not be measured because of a power limit of theanalyzing magnet and those of ions with valence higher than 4 were negligibly small.
In the monitoring experiment, Si4+ ions were selected and transported to a thick Cu target.
The leakage of X-rays was not detected. By removing part of shielding Pb plate of thickness
2 mm, surrounding the tank of SF 6 gas, leakage of X-rays became slightly detectable. Results of
the intensity distribution of measured X-rays are shown in Fig. I.
The leakage X-rays could not be detected around the target chamber.

oDFig. 1.
Distribution of leakage X-ray intensities(mR/h) at 1 m above the ground for Si ion
acceleration (4 MeV, 0.2SpA).
(2) Acceleration of Au ions
Acceleration of Au ions were carried out on the condition that current intensity of injected
Au- ions is 4 IlA and terminal voltage is 0.7 MV. In this operation, energies of accelerated Au 3+
and Au4+ ions were 2.8 MeV and 3.5 MeV, respectively and the currents were 1.2 /lA and 2.0 /lA,
respectively. Currents of Au+ and Au 2+ ions could not be measured and those of ions with valence
higher than 4 were negligibly small. In the monitoring measurement , Au 4+ ions were selected andtransported to a thick brass target. The leakage of X-rays was not detected as for the Si ions. By

238

removing the shielding Pb plate in the same way as for the Si ions, the intensity distribution ofleakage X-rays was measured as shown in Fig. 2.
No leakage X-rays was observed in this case too around the target chamber.

3 •.......-==="----oi'

o

U D
"

'.
Fig. 2.
Distribution of leakage X-ray intensities(mR/h) at 1 m above the ground for Au acceleration(3.5 MeV, 4,uA).

239

V -4.

Radiation Levels Due to Neutrons from the Cyclotron
outside the Cyclotron Building

T. Shikata, S. Fujita, 1. Kohno, H. Kamitsubo, M. Okano,
T. Nakamura, T. Kosako, A. Hara,* and S. Iwai*

Contribution of neutrons generated at the cyclotron to the environmental radiation level wasinvestigated in 1968, using a large BF 3 counter covered with 2 cm polyethylene moderator. It was
found that leakage flux from the cyclotron building gave an average increment of only several
percent of cosmic-ray level at the cyclotron monitoring post. 1)
Recently an experiment to study the effects of fast neutron irradiation in the plastics andelastmers started at our laboratory and high intensity neutrons were generated for many hours
in the cyclotron vault. Taking this opportunity, distribution of leakage neutron flux or dose
rates were measured at several points around the cyclotron.
As we did not know precise neutron spectra, we measured neutrons with three kinds ofdetectors having different sensitivity to high energy neutrons, to get as accurate data as possible.
A neutron rem counter, a BF3 counter (Bonner cylinder) and two helium-3 counters of different
gas pressures were used. The rem counter was calibrated in the neutron reference field at theElectrotechnical Laboratory. A conversion factor from the counting rate (counts/sec.) to dose
rate (J.Lrem/h) was obtained as 0.21 J.Lrem/ cps taking into account the energy dependence ofintensity in the neutron energy spectra. The BF 3 counter was used with and without the moderator.
Four polyethylene moderators of 1, 3, 6, and 10 cm in thickness covered with 0.5 mm cadmium
plate were prepared for it. The helium-3 counters which were developed by M. Okano et al. werealso used with and without polyethylene moderators, the effective thickness of which was 3, 6,
and 15 cm. The bare helium-3 counter is very sensitive to thermal neutrons and its sensitivity to
the fast neutrons (for example, En > 1 MeV) is 0.1 % or less compared with that to the thermal
neutrons 2) so that we can assume that it detect only slow neutrons.
Fast neutrons were generated in the cyclotron vault by bombarding a thick beryllium target
with 20 MeV deuterons. The average beam current was 10 J.LA. Neutrons were measured atvarious positions inside the campus of the institute, on the roof of the cyclotron building and in
the large experimental hall. Figure 1 shows the positions of the measurements. At the cyclotron
monitoring post (indicated as CMP in Fig. 1) neutrons were measured with all counters mentioned
above. The counting rates (cps) were tabulated in Table 1. Using conversion factor of neutron
rem counter the dose rate due to neutrons was estimated as 0.35 J.Lrem/h at the cyclotron
monitoring post. The conversion factor of the high pressure helium-3 counter with a moderatorof 15 cm thick was estimated to be 1.38 J.Lrem/ cps. From the data of this counter the dose rate
was obtained as 0.33 J.Lrem/h. Dose rate due to cosmic-ray neutrons, which is estimated as about
0.16 J.Lrem/h at the ground level in Japan, is included in these data.
The dose rates at the linac monitoring posts (indicated as LMP I and LMP II in Fig. 1) were
measured with helium-3 counters and obtained as 0.23 and 0.47 J.Lrem/h, respectively. Analysisof the data taken with other counters is in progress. From the present measurements it is* Institute for Nuclear Study. University of Tokyo.

240

(a )

®

C
~

Work shop

c:(]
.

/

r-,
L_J

/.

Nuclear fusion lab.

®
A

)
.( 5)

(3·).. .

• ( 4 ) I: tI===zt1l

C2J'(1)r: :,Large experimental
hall

Fig. 1.

Positions of the measurements.
(a) Plan of an environment around the cyclotron,(b) Positions of measurements of the neutron dose on the roof of thecyclotron building,(c) Positions of measurements of the neutron dose in the experimental hall.

confirmed that the radiation levels due to neutrons from the cyclotron are less than 1 mrem/year
even if we assume the cyclotron accelerates deuterons at highest energy for three thousands hours
which corresponds to two thirds of total beam time.
In order to compare these data with calculations of sky-shine, we measured neutron fluxes
on the roof of the cyclotron building. The results are given in Table 2. Dose rates in the large
experimental hall were also measured and listed in Table 3.

241

Table 1. Counting rates of neutron at the cyclotron monitoring post (CMP),
linac monitoring post I (LMP I) and II (LMP II).
Counting rates (counts per second)

Counters"

CMP
Rem counter(bare)
BF3(M-Io)a)
(M-6)

3He-I

(M-3)
(M-I)
(bare)b)

3H-II

(M-3)
(M-6)
(M-15)(bare )b)
(M-3)
(M-15)

LMPI

1.67
4.30
1.47
3.91

(E - 03)c)

4.26
1.46
3.83
6.5
5.3
2.4
1.15
1.15
1.27

(E - 02)(E - 02)(E - 01)(E - 01)

LMPII(E - 02)(E - 02)(E - 02)

4.16
3.22
4.37
1.68

(E - 01)(E - 01)(E - 01)(E - 01)(E - 01)(E - 01)

9.4(E - 01)

3.4 (E - 01)
1.22
1.2

a)

(M-I0) indicates that the detector is covered with a polyethylene moderator of 10 cm thick.

b)

3He-I and 3He-II are helium-3 counters, the gas pressure of which are 9.5 atm. and2.8 kg/cm 2 , respectively.
Read as 1.67 X 10-3 .

c)Table 2. Dose rates on the roof of the cyclotron building.
Measuring pointsa)
(1)
(2)
(3)
(5)

4.92
1.53
4.6
2.41
2.37

(6)
(7)
(8)
(9)

3.41
3.06
6.49
2.54

(10)
(11 )
(12)
(13)
(14)

1.35
2.97
8.35
7.17
3.42
1.73

(4)

(15)
J)

Counting rates (cps)Refer to Fig. 1(b)(E - 01)(E - 01)(E - 02)(E - 02)(E - 02)(E - 02)(E - 02)(E - 01)(E + 01)(E + 01)(E - 01)(E - 01)

Dese rates (mrem/h)
1.0
3.2
9.7
5.7
5.0
7.2
6.4
1.37
5.3
2.8
6.2
1.76
1.5
7.2
3.6

(E - 01)(E - 02)(E - 03)(E -- 03)
(E - 03)(E - 03)(E - 03)(E - 02)(E -- 01)
(E + 01)(E -- 01)
(E - 01)(E - 02)

242

Table 3. Dose rates in the large experimental hall.
Measuring pOints a)

Counting rates (cps)Dose rates (mrem/h)(1)1432.6
118.8
29.8
21.0
7.0

301.6
25.0
6.3
4.4
1.5

(2)
(3)
(4)
(5)
a)

Refer to Fig. 1(c)References
1)
2)

M. Wada, M. Okano, I. Sakamoto, and T. Hamada: IPCR Cyclotron Progr. Rep., 1, 163(1968).
T. Hamada, M. Okano, K. Izumo, T. Katou, H. Kumagai, and M. Nishida: Kankyo Hoshano
Chosa Kenkyu Seika Rombun Shorokushu, 22, 147 (1979); ibid., 23, 155 (1980).

243

V -5.

Radiation Shielding for the RIKEN

sse Facility

T. Shikata, T. Kosako,* S. Fujita,
S. Yamaji, and H. Kamitsubo

On the basis of the calculated results of Alsmiller et al. 1) and of Roussin et al. 2) a diagram which gives theneutron dose rate multiplied by r2 as a function of depth in the concrete shield was obtained previously. 3) To see
if there are any differences between the attenuation characteristics of parallel neutron beams incident on a slab 2)
and those of neutrons incident on a covering enclosing a point source, calculation was carried out with the ANISN
code. for the case of a spherical shell, at the center of which a monoenergetic neutron source was located. The
spherical shell has inner radius of 6 m and thickness of 3 m. Results compared with those of Roussin et al. areshown in Fig. 1. There are no significant differences between these two calculations. Therefore, our previous
estimation 3) based on the results of Alsmiller et al. and of Roussin et al. can be supposed to be justified.
The thickness of walls around the target area was decided to be 2 or 3 m from the point of view of materials
costs, but this thickness is inadequate to attenuate neutron dose beneath the proposed levels4 ) without beam
dumps. Double layer beam dumps which incorporats a combination of iron and concrete were designed, as theuse of ordinary concrete alone would result in the sacrifice of floor space.
Besides the estimation using a rough dose-geometry contours reported in a previous report,3)other calculations**

10- 4
calculation

10- 5
N

E

u

--......
C

2

10 - 6

-S
(lJ

c

~

1C- 7

(lJ

U
U
C

--......
E

10 - 8

~

10- 9

~
E

~
<U

>

::l
0(lJ

10 - 10

(lJ
(j)

0

0

10- 11

10- 12
10- 13(17.5- 20 )MeV
3Depth in the shield ( m)Fig. 1.

Dose equivalent vs. depth in shield.

Dashed line: slab.
Solid line: spherical shell.

* University of Tokyo, Institute for Nuclear Study. (Present Address: Research Center for Nuclear Science and Technology,
University of Tokyo.)** S. Ban calculated the attenuations of neutron flux in concrete and iron slabs with the HET and the ARIES codes formonoenergetic neutrons incident on slabs. He offered us the calculated results kindly for the sake of our shielding design for
RIKEN SSe. On the basis of this, we obtained a diagram showing the dose equivalent as a function of depth in iron andconcrete shields, for the given source4 ) with their emitting angles as parameters.

244

10- 7
10-

8

~

\
\\

10- 9
c
0
~
<l)

C

~
<l)

10- 10
10- 11cE-----<l)10- 13

E 10-

-+--'

C

14

\

>

10- 16~0<l)

10- 17r.n0Concrete spherical shell which has inner
radius of 6 m and thickness of 3 m.
Concrete beam dump which has

\

\

<l)

0

kind of shieldings.

\ 2:~~---~

10- 15<l)cuFig. 2.
Dose equivalent as a function ofradial distance from a point source for three~\'\W60Mev

10- 12~u- - Con cre te spher ical shell---- Concrete beam dump
- - - Iron - concrete beam dump

thickness of 3 m in radial direction anda spherical vacant space 0.1 m in radiusat the center .
Iron-concrete beam dump which has,\

10- 18I

10- 1910- 200.....

thickness of 0.8 m(iron) and 1 m-- --- --- --4

5

6

Distance from the source

7
( m)

8

(concrete) in radial direction,
respectively, and has a spherical
9

vacant space 0.1 m in radius at thecenter.

illustrate that the iron shielding of 0.8 m in thickness attenuates the neutron dose to nearly the same levels as
does the concrete shielding of 2 m in thickness for a given neutron source. 4 ) Dose attenuations for monoenergetic
neutrons in a spherical concrete beam dump, in a iron-concrete beam dump, and in a large spherical concrete shellmentioned above were calculated also with the ANISN code. Here, the thickness of the concrete beam dump inradial direction is 3 m, and that of iron-concrete beam dump is the sum of 0.8 m (iron) and 1 m (concrete). Bothbeam dumps have, respectively, a spherical vacant space 0.1 m in radius at the center. Results of calculation are
shown in Fig. 2. This shows that the spherical concrete beam dump and the large concrete spherical shellattenuate the neutron dose to nearly the same level at 9 m. Thus, our diagram 3) mentioned at the beginning of
this report seems to be appropriate for the shielding design of both wall and beam dump.
In designing the shield for high-energy accelerators, it is necessary to consider also the skyshine effect. In theprevious report,3) Thomas' empirical equation was applied for the designing purpose. But Thomas' equation
cannot be relied upon at a close distance such as the border of the campus which lies along the south side of thebuilding for the SSC facility. Alsmiller et al. 5) obtained the neutron importance functions, numerically, which
may be used to estimate the dose equivalent from skyshine at radial distances of 11, 108, 495, and 1005 m fora monoenergetic point source with energies ~ 400 MeV located 15 m above the ground and emitting neutrons
into the upper hemisphere. On the other hand, Nakamura and kosak0 6) showed a simple formula correlating theneutron dose equivalent (and/or flux) from skyshine as a function of the radial distance for the neutrons withenergies ~ 15 MeV emitted upwards isotropically within cones having several different apex angles from a pointon the ground. In our situation, the roof above a target area lies nearly on the same level as the ground and theenergies of neutrons passing through it will be in 175 MeV range. A simple application of Alsmiller et al.'s
method to our situation would lead to some underestimation of the dose equivalent from skyshine, because theeffects of the vertical location of the point source on the dose, especially at a close distance, are to be considered.
The energy dependence of the ratio of the dose equivalent from skyshine due to one neutron, calculated using
Nakamura and Kosako's formula compared to that calculated by Alsmiller et al., at radial distance of 11 m, isshown in Fig. 3. Here, as it is desirable that the shielding design should be performed somewhat with overestimation,
the emitting direction and emitting half apex angle of neutrons were selected to be 80 '" 90° (Alsmiller et al.)and 85° (Nakamura and Kosako), which give the largest dose equivalents at a close distance, respectively. Then, we
assume the ratio of the dose from skyshine above mentioned to be 3 for neutrons of energies> 15 MeV. Thus,a rough correction to our results estimated using Alsmiller et al.'s importance functions for 11 m was performed

245

~

~
<U

4

>

::::J
0Q)

3

Q)
(/)

0
-0
Q)

...c:

2

-+-'

'0
0
+-'

<U

0:::

1

10- 7

10- 3

10 - 2

En ergy of th e source neut ron

10 2( MeV )

Fig. 3.
Energy dependence of the ratio of the dose equivalent due to one
neutron emitted from the source calculated using Nakamura and Kosako's formula
to that calculated using Alsmiller et al.'s importance functions at radial distance ofII m. Emitting direction and emitting half apex angle of neutrons were selected
to be 80° '" 90° (Alsmiller et al.) and 8So (Nakamura and Kosako), respectively.

- - Dose rate f rom ala bora t ory( Beam loss : 1/1 A)---- Dose rate f rom t hee yc lotr on room
( Beam loss : 0.2/1 A)

Q)

(/)

o

o

10- 9

10- 10101

Fig. 4 .
Ra dial dista nce( m)

Corrected dose

rate from skyshine.

in the following way: the dose equivalent due to the neutrons with energy bin 15 '" 175 MeV was multiplied by
the factor 3, and this quantity was added to the dose equivalent due to neutrons of energies ~ IS MeV calculatedusing Nakamura and Kosako's formula. The dose equivalents at other distances (l08 , 495, 1005 m) were notcorrected, because they were not necessary for our shielding design explicity. The resultant diagram is shown in
Fig. 4.
Using Fig. 2 in Ref. 3 and Fig. 4 the radiation level at any place can be estimated easily. Shielding by means

246of the concrete covering of 2 or 3 m in thickness around the target area with the typical iron-concrete beam dumps(radial thickness in iron is 0.8 m and that in concrete is 1 '"'" 2 m) will be adequate to reduce radiation intensity
beneath the allowable levels.

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

R. G. Alsmiller, Jr., F. R. Mynatt, J. Barish, and W. W. Engle, Jr.: Nucl. Instr., 72, 213 (1969).
R. W. Roussin, R. G. Alsmiller, Jr., and J. Barish: Nucl. Eng. De~ign,.H., 250 (1973).
S. Fujita, S. Yamaji, and T. Shikata: Reports I.P.C.R. (in Japanese): 57,239 (1981).
S. Fujita, S. Yamaji, and T. Shikata: IPCR Cyclotron Progr. Rep., 14,203 (1980).
R. G. Alsmiller, Jr., J. Barish, and R. L. Childs: ORNL/TM-7512.
T. Nakamura and T. Kosako: Nucl. Sci. Eng., 77, 168 (1981).

247

VI.

LIST OF PUBLICATIONS

1.

Accelerator development and accelerator physics
1) N. Kishida, S. Kohmoto, A. Goto, E. Takenaka, and H. Kamitsubo: "Biological andPhysical Irradiation Beam Channel for the RIKEN SSC", Reports I.P.C.R., (in Japanese),58, 77 (1982).
Nuclear physics and nuclear instrumentation
1) H. Kudo, Y. Nagame, H. Nakahara, K. Miyano, and I. Kohno: "Correlation between
Angular Anisotropy and Fragment Mass in 15 MeV Proton-Induced Fission of 232Th",

2.

2)

3)

4)
5)
6)

3.

Phys. Rev. C, 25, 909 (1982).
H. Kudo, H. Muramatsu, H. Nakahara, K. Miyano, and I. Kohno: "Fission Fragment
Yields in the Fission of 232Th by Protons of Energies 8 to 22 MeV", Phys. Rev. C, 25,
3011 (1982).
S. Kohmoto, M. Ishihara, H. Kamitsubo, T. Nomura, Y. Gono, H. Utsunomiya,
T. Sugitate, and K. Ieki: "Final-State Interaction and Time Information in
14N-induced Reactions Studied by ~-a Correlations", Phys. Lett., l14B, 107 (1982).
T. Inamura and M. Wakai: "Calculation of Gamma-Ray Multiplicity Moments Associatedwith Massive-Transfer Reactions", J. Phys. Soc. Japan, ii, 1 (1982) .
M. Tohyama: "Proton Particle - Neutron Quasiparticle Calculations of the Isobaric
Analog Resonances of the Tin Isotopes", Prog. Theor. Phys., 68, L317 (1982).
T. Sugitate, T. Nomura, M. Ishihara, Y. Gono, H. Utsunomiya, K. Ieki, and S. Kohmoto:"Polarization of Preequilibrium Proton Emission in the 93Nb + 14N Reaction", Nucl.
Phys., A388, 402 (1982).

Atomic and solid-state physics
1) T. Tonuma, Y. Awaya, T. Kambara, H. Kumagai, M. Kase, A. Yagishita., and I. Kohno:"Krypton K{3/Ka Intensity Ratios for 6 MeV /amu Ion Bombardment", Inner-Shell and
X-Ray Physics of Atoms and Solids, Plenum Press, New York and London, p. 153(1981).
2) T. Tonuma, M. Kase, T. Matsuo, J. Urakawa, J. Takahashi, H. Kumagai, T. Kambara,
and I. Kohno: "Production of Highly-Charged Ions by Heavy-Ion Bombardment ofRare-Gas Targets", Atomic Collision Res. in Japan Progr. Rep., No.8, p. 96 (1982).
3) Y. Awaya, A. Hitachi, T. Kambara, M. Kase, H. Kumagai, T. Tonuma, and A. Yagishita:"A Broad Range X-Ray Crystal Spectrometer and Angular Distributions of X-Rays
Following Multiple Inner-Shell Ionization", Atomic Collision Res. in Japan Progr. Rep.,
No.8, p. 99 (1982).
4) A. Yagishita, T. Kambara, M. Kase, T. Tonuma, T. Matsuo, J. Urakawa, M. Namiki, andY. Awaya: "Argon LMM-Auger Electron Spectra in Ar 3+ + Ar Collisions", Atomic
Collision Res. in Japan Progr. Rep., No.8, p. 307 (1982).
5) T. Kambara, Y. Awaya, M. Kase, A. Hitachi, T. Tonuma, and I. Kohno: "Target Gas
Pressure Dependence of K X-Rays from 110 MeV Ne Ions", Atomic Collision Res. inJapan Progr. Rep., No.8, 321 (1982).

2486) A. Koyama, T. Shikata, H. Sakairi, and E. Vagi: "Secondary Electron Emission from
7)

8)
9)

10)
11)

12)
13)

14)

15)

16)

Metal Targets under Heavy Ion Bombardment", Jpn. J. Appl. Phys., 21, 586 (1982).
A. Koyama, T. Shikata, H. Sakairi, and E. Vagi: "Dependence of Secondary Electron
Emission Coefficients on Zl in Metal Targets under Bombardment with Bare Projectiles",Jpn. J. Appl. Phys., 21, 1216 (1982).
K. Maeda and M. Uda: "Computer Programs for Quantitative Analysis by PIXE-(I)",
Reports I.P.C.R., (in Japanese), 58, 96 (1982).
T. Kambara, Y. Awaya, A. Hitachi, M. Kase, I. Kohno, and T. Tonuma: "X-Rays from
Radiative Electron Capture Induced by 110 MeV Ne Ions", J. Phys. B: At. Mol. Phys.,
15, 3759 (1982).
A. Hitachi, H. Kumagai, and Y. Awaya: "Broad Range X-Ray Crystal Spectrometer",Nucl. Instr. Methods, 195, 631 (1982).
T. Okada, S. Ambe, F. Ambe, and H. Sekizawa: "Emission Mossbauer Studies ofCarrier-Free Pentavalent Antimony-119 Ions Adsorbed on a-Fe 20 3 and Cr 20 3", J. Phys.
Chern., 86, 4726 (1982).
K. Kaeda and M. Uda: "Radiative Auger Emission from KL Double Hole States", Phys.
Lett., 9lA, 223 (1982).
H. Endo and M. Uda: "Atomic Number Dependence of L-Shell Vacancy Rearrangement
Probabilities on Ka X-Ray Satellites Induced by 6 MeV /amu N4+ Impacts", Z. Phys. A,
306., 187 (1982).
Y. Awaya, H. Kumagai, and A. Hitachi: "Position Sensitive Proportional Counter for
X-ray Measurements", The Handbook of Atomic Collisions -Techniques-, Study Groupof Fundamental Atomic Process, (in Japanese), p. 74 (1982).
K. Ishii, M. Sebata, M. Kamiya, A. Kuwako, S. Morita, Y. Awaya, and T. Tonuma:"K-Shell Vacant Production in Light-Element with a Particles and N7+ Ions of 5, 6, and7 MeV/amu", J. Phys. Soc. Japan,jJ, 4021 (1982).
H. Sakairi, E. Vagi, A. Koyama, and R.R. Hasiguti: "The Damage Function Based on
the Focusing Model", Point Defects and Defect Interactions in Metals, Univ. of Tokyo
Press, Tokyo, p. 818 (1982).

4.

Radiochemistry, radiation chemistry and radiation biology
1) K. Kimura, K. Mochizuki, T. Fujisawa, and M. Imamura: "Measurement of the Decay
and Time-Resolved Spectra of the Emission from a-Excitons in KBr in- the Nano Second
Range, Produced by Heavy-Ion Irradiation", Phys. Letters, 78A, 108 (1980).
2) Y. Itoh and T. Nozaki: "Oxygen Depth Profiling by Activation with the 160eHe, p)18F
Reaction", J. Radioanal. Chern., 70, 329 (1982).
3) T. Nozaki: "Chemical Separation of 18F as KBF 4 in Oxygen Analysis by the 160eHe, p)
18F Reaction", J. Radioanal. Chern., 72, 527 (1982).
4) H. Emori, M. Umehara, M. Takeya, K. Nomura, Y. Terai, and T. Nozaki: "Determination of Oxygen in GaAs by 3He Activation Analysis", Gallium Arsenide and Related
Compounds 1981, Inst. Phys., Bristol, p. 47 (1982).
5) M. Iwamoto, T. Nozaki, Y. Takahashi, and K. Usami: "Distribution of Forward Recoil
Range of 18F Formed by Various Nuclear Reactions", Radiochim. Acta, 30, 73(1982).

249

6) T. Takahashi, F. Yatagai, K. Aoki, and S. Yamanaka: "Track Structure Theories andInactivation Cross Sections of Bacterial Spores for Heavy Ions", Ionizing Radiat., 9,
24 (1982).
7) T. Irie, K. Fukushi, O. Inoue, T. Yamasaki, T. Ido, and T. Nozaki: "Preparation of
18F-labeled 6- and 2-fluoro-9-benzylpurine as a Potential Brain-scanning Agent", Int.
J. appl. Radiat. Isotopes, 33, 633 (1982).
8) Y. Itoh and T. Nozaki: "Oxygen Depth Profiling in Heat-treated Silicon as Measured
by Charged Particle Activation Analysis", TG SSD 81-115"'"'130 IECE of Japan (1982).

(Papers Presented at Meetings)
1.

Accelerator development and accelerator physics
1) T. Fujisawa, K. Ogiwara, M. Hara, and S. Kohara: "Model Study of the Resonator for
the RIKEN SSC", 1982 Spring Meeting of the Phys. Soc. Japan, Tokyo, Mar. (1982).
2) M. Hara, T. Wada, A. Toyama, and F. Kikuchi: "Calculation of RF Electromagnetic
Field by Finite Element Method (II)", 1982 Spring Meeting of the Phys. Soc. Japan,
Tokyo, Apr. (1982).
3) N. Kishida, S. Kohmoto, A. Goto, E. Takenaka, and H. Kamitsubo: "Biological andPhysical Irradiation Beam Channel for the RIKEN SSC", 1982 Spring Meeting of the
Phys. Soc. Japan, Tokyo, Apr. (1982).
4) K. Ikegami, K. Ogiwara, I. Kohno, and T. Kageyama: "New Gas Feed System andAcceleration Test of Heavy Ions with Gas Mixing", 6th Symp. on Ion Source and IonAssisted Technology, Tokyo, June (1982).
5) M. Kase and Y. Miyazawa: "Heavy Ion Source for RIKEN Linac", 6th Symp. on Ion
Source and Ion-Assisted Technology, Tokyo, June (1982).
6) M. Kase: "Beam Bunch Probes of RIKEN Heavy Ion Linac", 7th Symp. on Linear
Accelerator, Tsukuba, Aug. (1982).
7) M. Kase, Y. Miyazawa, M. Hemmi, and T. Chiba: "Production of Various Ions with
PIG type Ion Source", 7th Symp. on Linear Accelerator, Tsukuba, Aug. (1982).
8) M. Yanokura: "ECR Heavy Ion Source for Linac (1)", 7th Symp. on Linear
Accelerator, Tsukuba, Aug. (1982).
9) M. Hara, T. Wada, T. Fukasawa, and F. Kikuchi: "Calculation of RF Electromagnetic
Field by Finite Element Method", Meeting of the Japan Soc. for Simulation Technology,
Tokyo, Sept. (1982).
10) M. Hara, T. Wada, T. Fukasawa, and F. Kikuchi: "Calculation of RF Electromagnetic
Field by Finite Element Method (111)", 37th Ann. Meeting of the Phys. Soc. Japan,
Sapporo, Oct. (1982).
11) M. Kase and T. Kubo: "Beam Bunch Probes at the RILAC", 37th Ann. Meeting of
the Phys. Soc. Japan, Sapporo, Oct. (1982).
12) M. Yanokura: "ECR Type Heavy Ion Source (1)", 37th Ann. Meeting of the Phys. Soc.
Japan, Sapporo, Oct. (1982).
13) H. Kamitsubo: "Status of RIKEN SSC", Proc. 4th Symp. on Accelerator Science andTechnology, Wako, Nov., p. 19 (1982).

25014) M. Odera and RILAC group: "Status of Operation of the Variable Frequency Heavy-Ion
Linac, RILAC", Proc. 4th Symp. on Accelerator Science and Technology, Wako, Nov.,
p. 53 (1982).
15) T. Shikata, S. Fujita, S. Yamaji, H. Kamitsubo, and T. Kosako: "Design of Radiation
Shielding for the RIKEN SSC", Proc. 4th Symp. on Accelerator Science and Technology,
Wako, Nov., p. 63 (1982).
16) N. Nakanishi, Y. Yano, and A. Goto: "The Effect of a Resonance on the Beam in the
RIKEN SSC", Proc. 4th Symp. on Accelerator Science and Technology, Wako, Nov.,
p. 99 (1982).
17) M. Kase: "Bunch Signal Sensitization by' Use of Secondary Electron Emission", Proc.
4th Symp. on Accelerator Science and Technology, Wako, Nov., p. III (1982).
18) I. Yokoyama, M. Kase, S. Kohara, and Y. Yano: "Bunch Phase Monitor", Proc. 4th
Symp. on Accelerator Science and Technology, Wako, Nov., p. 113 (1982).
19) M. Kase, M. Odera, T. Tonuma, and T. Kambara: "Linac Energy Tuning by Phase
Control of Last Cavity", Proc. 4th Symp. on Accelerator Science and Technology, Wako,
Nov., p. 115 (1982).
20) Y. Yano, N. Kishida, A. Goto, and N. Nakanishi: "Beam Diagnostic System for the
RIKEN SSC", Proc. 4th Symp. on Accelerator Science and Technology, Wako, Nov.,
p. 149 (1982).
21) S. Nakajima, K. Ikegami, Y. Oikawa, and I. Takeshita: "Design of the Acceleration
Chamber and the Evacuation System of the RIKEN SSC", Proc. 4th Symp. on
Accelerator Science and Technology, Wako, Nov., p. 203 (1982).
22) K. Ikegami, S. Nakajima, and Y. Oikawa: "Test of the Model Pneumatic Expansion
Seal", Proc. 4th Symp. on Accelerator Science and Technology, Wako, Nov., p. 207(1982).
23) Y. Ishibe, H. Ohyama, Y. Sakamoto, K. Ikegami, S. Nakajima, Y. Oikawa, and S.
Motonaga: "Preliminary Experiment on Discharge Cleaning of a Sector Magnet Vacuum
Chamber for the RIKEN SSC (1)", Proc. 4th Symp. on Accelerator Science andTechnology, Wako, Nov., p. 221 (1982).
24) K. Ikegami, S. Nakajima, Y. Oikawa, S. Motonaga, Y. Ishibe, H. Ohyama, and Y.
Sakamoto: "Preliminary Experiment on Discharge Cleaning of a Sector Magnet Vacuum
Chamber for the RIKEN SSC (2)", Proc. 4th Symp. on Accelerator Science andTechnology, Wako, Nov., p. 223 (1982).
25) T. Kageyama, K. Ikegami, K. Ogiwara, S. Kohara, and I. Kohno: "Heavy Ion Source
for IPCR Cyclotron", Proc. 4th Symp. on Accelerator Science and Technology, Wako,
Nov., p. 237 (1982).
26) M. Kase, Y. Miyazawa, T. Chiba, M. Hemmi, and T. Inoue: "Multiply Charged Ion
Production by the RILAC PIG Source", Proc. 4th Symp. on Accelerator Science andTechnology, Wako, Nov., p. 239 (1982).
27) K. Ogiwara, T. Fujisawa, and Y. Oikawa: "Model Test of 1/5 Scale Movable Box TypeRF Resonator for the RIKEN SSC", Proc. 4th Symp. on Accelerator Science andTechnology, Wako, Nov., p. 247 (1982).
28) S. Kohara, T. Fujisawa, and Y. Chiba: "Basic Study of the RF High Power Amplifier
for the RIKEN SSC (Study of the Screen Bypass Capacitor for the Final Stage)", Proc.

251

4th Symp. on Accelerator Science and Technology, Wako, Nov., p. 249 (1982).
29) M. Hara, T. Wada, T. Fukasawa, and F. Kikuchi: "Three Dimensional Analysis of RF
Electromagnetic Field by Finite Element Method", Proc. 4th Symp. on Accelerator
Science and Technology, Wako, Nov., p. 265 (1982).
30) M. Hara, T. Wada, T. Fukasawa, and F. Kikuchi: "Two Dimensional Analysis of RF
Electromagnetic Field by Finite Element Method", Proc. 4th Symp. on Accelerator
Science and Technology, Wako, Nov., p. 271 (1982).
31) S. Motonaga: "Present Status of the Sector Magnets of the RIKEN SSC", Proc. 4th
Symp. on Accelerator Science and Technology, Wako, Nov., p. 293 (1982).
32) A. Goto, H. Takebe, S. Motonaga, and T. Wada: "Measurements on the Trim Coil
Fields and Optimization of the Trim Coil Currents for the RIKEN SSC", Proc. 4th
Symp. on Accelerator Science and Technology, Wako, Nov., p. 295 (1982).
33) H. Takebe, 1. Takeshita, J. Fujita, 1. Yokoyama, T. Wada, and S. Motonaga: "Magnetic
Field Measuring System for the RIKEN SSC Sector Magnets", Proc. 4th Symp. on
Accelerator Science and Technology, Wako, Nov., p. 301 (1982).
34) N. Kishida and Y. Yano: "Design Study of Magnetic Deflection Channels for the RIKEN
SSC", Proc. 4th Symp. on Accelerator Science and Technology, Wako, Nov., p. 309(1982).
35) M. Hara, T. Wada, and M. Deto: "Dynamic Structural Analysis of the Sector Magnet of
the RIKEN SSC", Proc. 4th Symp. on Accelerator Science and Technology, Wako, Nov.,
p. 323 (1982).
36) T. Inamura, N. Kishida, and Y. Hata: "The RIKEN SSC Beam Handling System", Proc.
4th Symp. on Accelerator Science and Technology, '''ako, Nov., p. 345 (1982).
37) 1. Fujita, T. Kambara, K. Simizu, T. Wada, Y. Yano, and 1. Yokoyama: "Design ofControl System of the RIKEN SSC", Proc. 4th Symp. on Accelerator Science andTechnology, Wako, Nov., p. 365 (1982).
38) F. Kikuchi: "Three Dimensional Finite Element Program for Electromagnetic Waves",
Theoretical Research on Diagnostic Methods in Fusion Plasma, Hakone, Nov. (1982).
2.

Nuclear physics and nuclear instrumentation
1) T. Inamura: "Massive Transfer", Symp. on Mechanism of Heavy Ion Reactions, Tokyo,
Feb. (1982).
2) T. Hasegawa, S. Kubono, N. Ueda, K. Iwatani, C. Tohei, K. Murakami, T. Fujisawa,---*
and M. Sugitani: "Measurement of the Vector Analyzing Power of (d, 6Li) Reaction",1982 Spring Meeting of the Phys. Soc. Japan, Tokyo, Mar. (1982).
3) M. Sugitani, T. Hasegawa, Y. Ishizaki, S. Kubono, N. Ueda, K. Iwatani, T. Fujisawa,
K. Murakami, and H. Nakamura: "Study of the Excited States of 24Mg<p, p') 24Mg
Reaction", 1982 Spring Meeting of the Phys. Soc. Japan, Tokyo, Mar. (1982).
4) Y. Gono: "High Spin States in Pb Region", 1982 Spring Meeting of the Phys. Soc.
Japan, Tokyo, Mar. (1982).
5) Y. Itoh, Y. Gono, M. Sasagase, T. Kubo, and M. Sugawara: "In-beam -y-Ray Spectroscopyof 216Ra", 1982 Spring Meeting of the Phys. Soc. Japan, Tokyo, Mar. (1982).
6) T. Inamura, M. Ishihara, K. Ieki, and S. Kohmoto: "In-plane/Out-of-plane Anisotropy ofGamma Rays from the 159Tb(14N, ~xn) Reactions at E = 115 MeV", 1982 Spring Meeting of
the Phys. Soc. Japan, Tokyo, Apr. (1982).

252

7) A. Hashizume and T. Inamura: "Analysis of Deexcitation Gamma Rays from Multiply
Coulomb-Excited 167Er", 1982 Spring Meeting of the Phys. Soc. Japan, Tokyo , Apr.
(1982).
8) K. Ieki and M. Ishihara: "I-Ray Circular Polarimeter", 1982 Spring Meeting of the
Phys. Soc. Japan, Tokyo, Apr. (1982).
9) S. Yamaji, A. Iwamoto, K. Harada, and S. Yoshida: "A Numerical Analysis of 1280
MeV 2oBPb-induced Reactions on 94 Zr , llOpd, 14BSm and 17Df:r" , 1982 Spring Meeting of
the Phys. Soc. Japan, Tokyo, Apr. (1982).
10) T. Kubo, H. Ohnuma, T. Kishimoto, M. Sugitani, and T. Suehiro: "Deuteron D-state
Effects on (d, p) Reaction at 55 MeV", 1982 Spring Meeting of the Phys. Soc. Japan,
Tokyo, Apr. (1982).
11) I. Kohno: "Fission-like Heavy Fragments on Heavy Ion Nuclear Reaction", 1982 Spring
Meeting of the Phys. Soc. Japan, Tokyo, Apr. (1982).
12) M. Ohshima, E. Minehara, M. Ishii, T. Inamura, and A. Hashizume: "Multiple Coulomb
Excitation of 167Er", INS Intern. Symp. on Dynamics of Nuclear Collective Motion,
Fuji-Yoshida, July (1982).
13) Y. Gono: "In-Beam ~- and I-Ray Study on 215Fr and 217Ac", INS Intern. Symp. on
Dynamics of Nuclear Collective Motion, Fuji-Yoshida, July (1982).
14) S. Yamaji, A. Iwamoto, K. Harada, and S. Yoshida: "Effect of the Mass Fragmentation
Potential on the Width of the Mass Distribution in the Deep Inelastic Heavy Ion Colljsion",Intern. Conf. on Nucleus-Nucleus Collisons, Michigan, Sept. (1982).
15) M. Tohyama and S. Yamaji: "Two Particle- Two Hole Effects on the Mass Distributionsin Deep Inelastic Heavy Ion Collisions", Intern. Conf. on Nucleus -Nucleus Collisions,
Michigan, Sept. (1982).
16) M. Tohyama and S. Yamaji: "A Treatment of the Mass Distributions in Deep Inelastic
Heavy Ion Collisions in the Time-dependent Coupled-Cluster Approximation", 37th Ann.
Meeting of the Phys. Soc. Japan, Sapporo, Sept. (1982).
17) Y. Itoh, Y. Gono, T. Kubo, M. Sugawara, S. Hayashibe, M. Sasagase, T. Kono, andT. Nomura: "Levels in 21BRa and Dipole Transistions", 37th Ann. Meeting of the Phys.
Soc. Japan, Sapporo, Sept. (1982).
18) I. Kohno, Y. Nagame, K. Sueki, and H. Nakahara: "Heavy Particle Emitting Reactions
from 146 MeV 2~e + 92 ,lOCMo Systems", 37th Ann. Meeting of the Phys. Soc. Japan,
Sapporo, Oct. (1982).
19) K. Ieki, M. Ishihara, T. Inamura, S. Kohmoto, and H. Utsunomiya: "Circular
Polarization of I-rays Emitted in Heavy Ion Reactions", 37th Ann. Meeting of the Phys.
Soc. Japan, Sapporo, Oct. (1982).
20) M. Ohshima, E. Minehara, M. Ishii, T. Inamura, and A. Hashizume: "Transition
Probabilities in the Groun-State Rotational Band of 167Er", 37th Ann. Meeting of the
Phys. Soc. Japan, Sapporo, Oct. (1982).

(p,d)21) T. Kubo, H. Ohnuma, T. Kishimoto, M. Sugitani, and T. Suehiro: "(d, p) andReactions on Sn Isotopes", 37th Ann. Meeting of the Phys. Soc. Japan, Sapporo, Oct.
(1982).
22) M. Takahashi, Y. Nagame, K. Sueki, and H. Nakahara: "eHe, n) Reactions", 26th Symp.
on Radiochemistry, Niigata, Oct. (1982).

25323) K. Sueki, H. Nakahara, Y. Nagame, M. Takahashi, and I. Kohno: "Heavy-Ion Reaction
between 14N and 62Ni, the Excitation Functions Evaporation-like Products", 26th Symp.
on Radiochemistry, Niigata, Oct. (1982).
24) H. Sakairi, E. Vagi, T. Kobayashi, and T. Urai: "RIKEN TANDETRON", Proc. 4th
Symp. on Accelerator Science and Technology, Wako, Nov., p. 335 (1982).
3.

Atomic and solid-state physics
1) T. Doke and T. Takahashi: "Stopping Powers of Ni, Ag, Au, and Pb for 7 MeV/na-Particles and Carbon Ions (Zi Proportional Deviations from the Bethe Formula)",Japan - U.S. Seminar, Honolulu, Jan. (1982).
2) S. Sato, A. Masuyama, M. Iwaki, and H. Sakairi: "Ion Implantation in Diamond (II)",
29th Spring Meeting of the Japan Soc. Appl. Phys., Tokyo, Apr. (1982).
3) K. Aono and S. Namba: "Pulsed Laser Annealing of Ion Implanted GaP (V 1)", 29th
Spring Meeting of the Japan Soc. Appl. Phys., Tokyo, Apr. (1982).
4) A. Yagishita, T. Kambara, M. Kase, T. Tonuma, Y. Awaya, and Y. Miyazawa: "Ar
L-M~1 Auger Spectra in Arn+ + Ar (n = 2, 3, 4) Collisions", 1982 Spring Meeting of the
Phys. Soc. Japan, Yokohama, Apr. (1982).
5) T. Tonuma, A. Yagishita, M. Kase, T. Kambara, Y. Awaya, and I. Kohno: "Secondary
Ion Production in Heavy-ion Atom Collisions", 1982 Spring Meeting of the Phys. Soc.
Japan, Yokohama, Apr. (1982).
6) T. Takahashi, Y. Awaya, T. Tonuma, K. Izumo, A. Hashizume, A. Hitachi, S. Uchiyama,
and T. Doke: "Stopping Powers for 7 MeV In Carbon Ions and a-Particles", 1982 Spring
Meeting of the Japan Soc. Appl. Phys., Tokyo, Apr. (1982).
7) Y. Awaya, A. Hitachi, H. Kumagai, T. Kambara, T. Tonuma, M. Kase, A. Yagishita,
T. Matsuo, J. Urakawa, and J. Takahashi: "Studies of Multiple-Innershell Ionizations
by X-Ray Measurements", 6th Meeting of the Soc. for Atomic Collision Research,
Tokyo, July (1982).
8) T. Matsuo, J. Urakawa, A. Yagishita, T. Kambara, M. Kase, Y. Awaya, and J. Takahashi:"Ar L-MM Auger Spectra in Ar 3+ + Ar Collisions", 6th Meeting of the Soc. for Atomic
Collision Research, Tokyo, July (1982).
9) K. Maeda and M. Uda: "RAE Satellite from KL Double Hole State", Intern. Conf. on
X-Ray and Atomic Inner-Shell Physic, Eugene, Aug. (1982).
10) K. Fujima, K. Fuwa, and M. Uda: "Intensity Analysis of F Ka-Emission Satellite Spectra
for Fluorine Compounds by the DV -Xa Method", Intern. Conf. on X-Ray and Atomic
Inner-Shell Physics, Eugene, Aug. (1982).
11) H. Endo and M. Uda: "Z2 Dependence of L-Shell Vacancy Rearrangement Probability on
Ka X-Ray Satellite", Intern. Conf. on X-Ray and Atomic Inner-Shell Physics, Eugene,
Aug. (1982).
12) K. Aono, M. Iwaki, and S. Namba: "Annealing of Ion Implanted Gap", 43th Fall
Meeting of the Japan Soc. Appl. Phys., Fukuoka, Sept. (1982).
13) S. Sato, A. Masuyama, M. Iwaki, and H. Sakairi: "Ion Implantation in Diamond (III)",
43th Fall Meeting of the Japan Soc. Appl. Phys., Fukuoka, Sept. (1982).
14) K. Oda, Y. Watanabe, S. Nanao, and N. Shiotani: "Radiation Damage in an Amorphous
Fe soB20 Alloy Bombarded with C4+ Ions", 91 st Meeting of the Japan Inst. Metals,
Sapporo, Sept. (1982).

25415) Y. Higashiguchi, M. Narui, Y. Suzuki, H. Kayano, and E. Yagi: "Helium Embrittlementof Ti-Al Alloys", 91 st Meeting of the Japan Inst. Metals, Sapporo, Sept. (1982).
16) N. Nishiyama, K. Nagamine, T. Natsui, S. Nakajima, K. Ishida, Y. Kuno, J. Imazato,
H. Nakayama, T. Yamazaki, and E. Yagi: "Critical Phenomena in Ni Studied with
Pulsed ,uSR", Intern. Conf. Magnetism, Kyoto, Sept. (1982).
17) K. Nishiyama, E. Yagi, K. Ishida, and K. Nagamine: "Muon Spin Rotation andResonance in Ni Crystal", 37th Ann. Meeting of the Phys. Soc. Japan, Sapporo, Oct.
(1982).
18) Y. Awaya, T. Kambara, M. Kase, H. Kumagai, T. Matsuo, J. Urakawa, J. Takahashi,
and M. Namiki: "Projectile Ar K X-Rays following Multiple Inner-Shell Ionization in
Ar-ion-foil collisions at 30 MeV", 37th Ann. Meeting of the Phys. Soc. Japan, Sapporo,Oct. (1982).
19) T. Kambara, Y. Awaya, M. Kase, 1. Kohno, T. Tonuma, and A. Hitachi: "Target Gas
Pressure Dependence of K-X Rays from 110 MeV Ne Ions", 37th Ann. Meeting of the
Phys. Soc. Japan, Sapporo, Oct. (1982).
20) T. Matsuo, J. Urakawa, A. Yagishita, T. Kambara, M. Kase, J. Takahashi, and Y. Awaya:"Ar L-MM Auger Electron Spectra in Ar 3 + + Ar Collisions", 37th Ann. Meeting of the
Phys. Soc. Japan, Sapporo, Oct. (1982).
21) T. Akioka, M. Kase, J. Kikuchi, and T. Doke: "Fano Factor of Xe Gas", 37th Ann.
Meeting of the Phys. Soc. Japan, Sapporo, Oct. (1982).
22) A. Hitachi, Y. Awaya, J. Takahashi, H. Kumagai, T. Kambara, M. Kase, T. Tonuma,
and A. Yagishita: "Angular Distributions of X-rays Following Multiple Inner-Shell
Ionizations", 37th Ann. Meeting of the Phys. Soc. Japan, Sapporo, Oct. (1982).
23) T. Tonuma, M. Kase, T. Matsuo, J. Urakawa, J. Takahashi, H. Kumagai, T. Kambara,
and 1. Kohno: "Production of Highly-Charged Ions by Heavy-Ion Bombardment ofRare-Gas Targets", 37th Meeting of the Phys. Soc. Japan, Sapporo, Oct. (1982).
24) K. Fujima, K. Fuwa, and M. Uda.: "The Intensity Analysis of X-Ray Emission fromthe Compounds in Multi-Ionized States-I", 37th Ann. Meeting of the Phys. Soc. Japan,
Sapporo, Oct. (1982).
25) K. Fuwa, K. Fujima, and M. Uda: "The Intensity Analysis of X-Ray Emission fromthe Compounds in Multi-Ionized States-II", 37th Ann. Meeting of the Phys. Soc. Japan,
Sapporo, Oct. (1982).
26) M. Uda, K. Maeda, Y. Sasa, A. Koyama, and S. Nakamura: "Chemical Effects on 0 Ka
Spectra Emitted from Multiply Ionized States", 37th Ann. Meeting of the Phys. Soc.
Japan, Sapporo, Oct. (1982).
27) K. Maeda, Y. Sasa, and M. Uda: "Data Processing for Quantitative Analysis by PIXE",
18th Oyo Spectrometry Tokyo Toronkai (18th Tokyo Symp. on Applied Spectrometry),
Tokyo, Nov. (1982).
28) H. Sakairi: "Electron Microscopic Observation on Heavy Ion Irradiation Damage", 12th
Symp. on Fusion Reactor Materials, Nagoya, Dec. (1982).
4.

Radiochemistry, radiation chemistry and radiation biology
1) Y. Itoh and T. Nozaki: "Oxygen Depth Profilin in Heat-treated Silicon as measured by
Charged Particle Activation Analysis", Meeting of Technical Group on Semiconductors

255

and Semiconductor Devices, Osaka, Feb. (1982).
2) T. Takahashi and F. Yatagai: "Recent Development of Plastic Track Detectors,
Application for Biology and Medicine, Spring Meeting of Japan Soc. Appl. Phys.,
Tokyo, Apr. (1982).
3) T. Takahashi, F. Yatagai, and S. Kitayama: "Effect of Heavy Ions on Bacterial Spores
and Phages", 24th Committee on Space Research, Ottawa, May (1982).
4) H. Nagai, M. Aratani, T. Nozaki, M. Yanokura, and I. Kohno: "Rutherford Scattering
Applied to the Study of Hydrogen in Amorphous Silicon", 6th Symp. on Ion Sources
and Ion-Assisted Technology, Tokyo, June (1982).
S) K. Niisawa, J. Saito, K. Taki, T. Karasawa, and T. Nozaki: "The Reaction of uC0 2 ina Microwave Discharge", Sth Intern Symp. Radiopharm. Chern., Jillich, Aug. (1982).
6) K. Ogawa, K. Taki, and T. Nozaki: "Synthesis of 73Se- or 7sSe-Labeled Compounds by
the Isotopic Exchange with Elemental Selenium-73 or -7S", Sth Intern Symp.
Radiopharm. Chern., Julich, Aug. (1982).
7) T. Hara and T. Nozaki: "Radioactivity Labeling of C-l Position of Glucose andMannose", Sth Intern. Symp. Radiopharm. Chern., JUlich, Aug. (1982).
8) T. Irie, K. Fukushi, O. Inoue, T. Yamasaki, Y. Kasida, T. Ido, and T. Nozaki:"l8F-Labeled 6-Fluoro-Purine Derivatives as a New Brain Scanning Agent", Sth Intern.
Symp. Radiopharm. Chern., Julich, Aug. (1982).
9) M. Yanokura, H. Nagai, M. Aratani, T. Nozaki, and I. Kohno: "Rutherford Scattering
Applied to the Study of Hydrogen in Amorphous Silicon", 7th Meeting on Linear
Accelerator in Japan Ibaragi, Aug. (1982).
10) Y. Itoh and T. Nozaki: "Heat Treatment Effect of Carbon and Oxygen to Gold
Diffusion in Silicon", Fall Meeting of the Appl. Phys. Soc. Japan, Fukuoka, Sept.
(1982).
11) G. Okada, K. Kurita, K. Nakano, and I. Kaneko: "Mutagenesis of Chinese Hamster
V79 Cells by Nitrogen Particles", 24th Ann. Meeting of the Japan Radiat. Res. Soc.,
Akita, Oct. (1982).
12) T. Ohno, T. Nishimura, G. Okada, K. Nakano, and I. Kaneko: "Recovery from
Potentially Lethal Damage of Human Normal Fibroblast Cells after Irradiation of
Nitrogen Ion Beams", 24th Ann. Meeting of the Japan Radiat. Res. Soc., Akita, Oct.
(1982).
13) K. Eguchi, S. Satoh, M. Yaguchi, T. Inada, and I. Kaneko: "LET Dependency of the
PLD of HMV-l Cells", 24th Ann. Meeting of the Japan Radiat. Res. Soc., Akita, Oct.
(1982).
14) K. Eguchi, S. Satoh, M. Yaguchi, T. Inada, and I. Kaneko: "Effect of Nitogen Ion
Radiation on the DNA damage and Its Rejoining", 24th Ann. Meeting of the Japan
Radiat. Res. Soc., Akita, Oct. (1982).
IS) S. Ambe: "Separation of Trace Elements, In(lII), Sn(lV), Sb(V), and Te(lV) by
Adsorption on Activated Carbon and Graphite", 26th Symp. on Radiochem., Niigata,Oct. (1982).
16) T. Nozaki and Y. Itoh: "Measurement of Oxygen Solubility and Diffusion Coefficientof Oxygen in Silicon", 26th Symp. on Radiochem., Niigata, Oct. (1982).
17) F. Ambe, S. Ambe, T. Okada, and H. Sekizawa: "Emission Mossbauer Studies of256

Carrier-Free 119Sb5+ and 57C02+ Adsorbed on Magnetic Oxide Surfaces", 26th Symp. on
Radiochem., Niigata, Oct. (1982).
18) H. Nagai, M. Aratani, T. Nozaki, M. Yanokura, and I. Kohno, O. Kuboi, and Y.
Yatsurugi: "Rutherford Forward Scattering Applied to the Analysis of Hydrogen", 26th
Ann. Meeting of Radiochem., Niigata, Oct. (1982).
19) K. Kimura, Y. Toda, and M. Imamura: "Extraordinary Emission of He-gas near Critical
Temperature Irradiated by N 7+-Ions", 25th Conf. on Radiat. Chern., Sendai, Oct. (1982).
20) F. Yatagai and K. Nakano: "Application of Thermoluminescence Dosimeter for Dose
Measurement of High LET Radiation", Proc. 4th Symp. on Accelerator Science andTechnology, Wako, Nov., p. 185 (1982).
21) G. Okada, K. Kurita, T. Nishimura, K. Nakano, and I. Kaneko: "Mutation Induction ofChinese Hamster V79 Cells by Nitrogen Ion Beams", Proc. 4th Symp. on Accelerator
Science and Technology, Wako, Nov., p. 189 (1982).
22) I. Kaneko, T. Ohno, T. Nishimura, G. Okada, and K. Nakano: "Recovery from Potentially
Lethal Damage of Human Normal Fibroblast IMR 90 Cells after Irradiation of Nitrogen
Ion Beams", Proc. 4th Symp. on Accelerator Science and Technology, Wako, Nov.,
p. 191 (1982).
23) K. Eguchi, S. Sato, M. Yaguchi, T. Inada, K. Kobayashi, and I. Kaneko: "Recovery
from Potentially Lethal Damage of Human Melanoma Cells after Irradiation of Proton
and Nitrogen Ion Beam", Proc. 4th Symp. on Accelerator Science and Technology,
Wako,Nov., p. 193 (1982).
24) I. Kaneko, K. Eguchi, T. Ohno, S. Satoh, T. Inada, and K. Nakano: "Recovery from
Potentially Lethal Damage of Human Cells after Irradiation of Proton and Nitrogen
Ion Beams", 5th Radiation Biology Center Intern. Symp. on DNA Repair and Chemical
Damage, Moriyama, Nov. (1982).

257

VIT.

LIST OF OUTSIDE USERS AND THEIR THEMES(Jan. - Dec. 1982)
1)

S. Yoshida and K. Mitsui

LSI R&D Lab.

"Study of Effect by Bombarding High

Mitsubishi Electric Co., Ltd.

Energy Proton on a GaAs Solar Cell"
2)

3)

4)

H. Nakahara and T. Miura

Faculty of Science, Tokyo"Production of 77Br and 58Co"

Metropolitan Univ.

K. Yuita

National Inst. of Agricultural"Production of 77Br and 43K"

Sciences

T. AbeShinetsu Semiconductor Co., Ltd.

"Radiochemical Analysis of 16 0 in
Si Crystal"
5)

K. Usami

Central Res. Lab., Hitachi Ltd.

"Radiochemical Analysis of 14N in
Si Crystal"

6)

H. Shinyashiki"Radiochemical Analysis of 160

7)

Central Res. Lab., Mitsubishi
in GaAs"

Metal Co., Ltd.

H. Muraoka

Semiconductor Div., Toshiba"Radiochemical Analysis of 14N

Electric Co., Ltd.

in Si Crystal"8)

T. lizuka

Japan Electric Industry"Radiochemical Analysis of 160

Developing Association (JEIDA)

in Si Crystal"9)

Y. Higashiguchi

Research Inst. for Iron, Steel and"Study of Effect by Bombarding High

Other Metals, Tohoku Univ.

Energy Helium on a Reactor Material"

Irradiation Research Lab. in JMTR

258

10)

M. Koitabashi

Central Res. Lab., Mitsubishi"Study of Effect by Bombarding HighElectric Co., Ltd.

Energy Proton on a Teflon Plate Coatedby a Silver"
11 )S. Suzuki

Space Development Div.,"Study of Effect by Bombarding HighNissan Automobile Co., Ltd.

Energy Proton on a Solid Fuel for a
Rocket"12)

M. Yatsuhashi and T. Suema tsu

Fujikura Cable Works, Ltd.

"Study of Effect by Irradiating
Fast Neutron on a Insulator Coveringa Cable"13)

A. Morio and M. Harada

Japan Trust Center for"Study of Single Event Upset inElectronic Parts

Microprocessors by Bombarding
2~e Particles"

259

Vill.

LIST OF SEMINARS(Jan. - Dec. 1982)
1)

A. van der Woude, KVI (Holland), 26 January"Barrier Properties of 23 2Th and 238U Deduced from Fission by Charged Particle Reactions"

2)

K. Niita, Tohoku Univ. (Sendai), 28 January"Double Differential Cross Sections Based on the Quasi-Linear Response Theory"3)

F. Fukuzawa, Kyoto Univ. (Kyoto), 16 March"Experiment of Atomic Collisions in Denmark"4)

T. Kurihara, INS (Tokyo), 23 March"Study of 208Pb(a, 6He)206Pb Reaction and Systematic Studies of Neutron Pick-up
Reactions"

5)

M. Morinaga, Tech. Univ. Miinchen (West Germany), 30 April"Experiments using 250 MeV Nickel Beam; i) Spectroscopy of N = 82 Proton-Rich
Nuclei, and ii) Super Multi-Nucleon Transfer"

6)J. Kasagi, Tokyo Inst. Tech. (Tokyo), 9 June
"Comparison of Non-Compound Neutron and Proton Emission in 160-induced
Reaction on 238U"

7)

M. Sakai, INS (Tokyo), 16 June
"Study of Nuclear Physics after the Second World War"

8)

T. Izumoto, Texas A & M Univ. (USA), 29 June
"Pionic Modes of Excitation in Continuum from (p, n) Reaction"

9)

T. Tamura, Univ. Texas at Austin (USA), 21 July
"Boson Expansion"

10)

U. Mosel, Giessen Univ.,(West Germany), 22 July
"Molecular Resonance in Inelastic Scattering of Light-Heavy Ion"

11)

I. Hamamoto, Nordita (Denmark), 23 July

"Residual Interactions in High Spin States"
12)

K. Rara, Tech. Univ. Miinchen (West Germany), 27 July
"Random Coupled Channel; A Model for DIC"

260

13)

H. Yamada, Venderbilt Univ. Tennessee (USA), 12 August"Massive-Transfer Reaction"

14)

H. Morinaga, Tech. Univ. Miinchen (West Germany), 8 September"Cyclotron vs. Linac"

15)

I. Hofmann., Max-Planck-Institute (West Germany), 21 September"Calculation of Orbits for Heavy Ion Accelerators"
16)

J.Y. Park, North Carolina State Univ. (USA), 2 November"Theory of Nuclear Molecular States in Heavy Ion Collisions"

17)

S. Iwasaki, Chiba Univ. (Chiba), 15 November"Treatment of Band Crossion using Angular Momentum Projection Method"18)

A. Ikeda, Tokyo Inst. Tech. (Tokyo), 30 November"Attenuation of Zero-Sound Wave at T = 0°"

19)

S. Morinobu, RCNP (Osaka), 15 December"On On-Line Mass Separator"

20)

S. Hayakawa, Ashikaga Inst. of Tech., 21 December"M 1 Strength in 208Pb''

261

IX.

LIST OF PERSONNEL

Members of the Board
HAMADA Tatsuji i~ ill Ji EIIMAMURA Masashi ~ ft
E3
KOHNO Isao ill]"!ff
JjJ
NOZAKI Tadashi ff ~iE (Chairman)
SAKAIRI Hideo :tJX A
b:lSHIMA Makoto ~
~JOC

*

M
HASHIZUME Akira m Jl\
KAMITSUBO Hiromichi 1:: tiL 7i it
MORI Kazuo ~ODERA Masatoshi /J~ ~ 1£ 1~
SEKIZAWA Hisashi ~?~r#J
UDA Masayuki :=f: ill IZ L'*

Cyclotron Operation and Maintenance GroupIKEGAMI Kumio it!! 1: 11 = ~KOHARA Shigeo /J~!I!
OGIW ARA Kiyoshi -gJ(
~N

FUJITA Shin iii ill$Jf
KAGEY AMA Tadashi '5 ill
KOHNO Isao iliJ ff
JjJ
T AKEBE Hideki fE\: {f~
fM

'*

*

'*

'*

Linac Operation and Maintenance GroupCHIBA Yoshiaki -=r ~ !if B?5
HEMMI Masatake ~ J! i& fE\:
INOUE Toshihiko j:j: 1:: fij!J: ~KASE Masayuki 110 ~~j ~ L
MIY AZAWAY oshitoshi g i~ f* fij!J:
Y ANOKURA Minoru ~!ff:@~

GONO Yasuyuki ~~ III AA L
IKEZAWA Eiji it!! i~
KAMBARA Tadashi 1$
1£
KUBO Toshiyuki 7. f* fij!J: ¥TONUMA Tadao P m 1£ b:l* ='*Scientific and Engineering Personnel

Cyclotron Laboratory±Ju.,
FUJISAWA Takashi iii ¥~ -afi'iJ
GOTO Akira 1~ iii
~
i1}:
rP
ft
ICHIMURA Atsushi!j[
INAMURA Takashi ~ffi i't
KAMITSUBO Hiromichi 1:: :l3¥ 7i it
KISHIDA Norio I¥ ill IlJj 1:.
JjJ
KOHNO Isao iliJ ff
MOTONAGA Shoshichi j[; 71< B?5 -t
NAKANISHI Noriyoshi t:p i§%
OIKAWA Yoshifumi ~ )II • 1m
SHIMIZU Kazuo m -* fD ~TOYAMA Mitsuru Ji ill
fr;ilJ
WADA Takeshi fD illb:l
YANO Y asushige ~ !ff 1i: ~*c'*(Visitors)
HIRUTA Kotaro~

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YOKOY AMA Ichiro II LIJ - f!~(Dept. Phys., Tokyo Gakugei Univ.)

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ICHIMURA Munetake(Inst. Phys., College General Education, Univ. ofTokyo)KIKUCHI Fumio 1W Jill Jt ~ (Dept. Math., College of General Education, Univ. ofTokyo)KOSAKO Toshiso IJ"ftc:~ fii!J: ;jf (Inst. Nucl. Phys., Univ. of Tokyo)
MORINAGA Haruhiko ~ 7k H~ ~ (Dept. Phys., Technische Universitat Munchen)
NAKAHARA Hiromichi ~ I}j( ~L J!! (Dept. Chern., Tokyo Metropolitan Univ.)
NAKAMURA Takashi ~ :ft foJ P] (Inst. Nucl. Phys., Univ. of Tokyo)
OZKOK Seuket(Dept. Phys., Istanbul Univ.)
SATO Kenichi ftc: ~ ~ - (Dept. Phys., Tohoku College of Pharmacy)
SHIRAISHI Haruki E3 15
tNt (Nat. Res. Inst. for Metals)
TAKEMASA Tadashi m: i& Jr ± (Dept. Phys., Saga Univ.)
TAKIGAWA Noboru i~)l1
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YOSHIDA Shiro E 133 JIG', g~ (Dept. Phys., Tohoku Univ.)
ZHANG Zhenkang iJftt~ ~ (Inst. Mod. Phys., Academia Sinica)
ZHOU Sixin}@
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AMANO Koichi 7Z '} -Jt - (Facul. Sci. and Eng., Chuo Univ.)
DETO Masuo tfj pi 1iiE ~ (College of Hum. and Sci., Nihon Univ.)
FUKASAWA Tsutomu 7* iR~ (College of Hum. and Sci., Nihon Univ.)
HAT A Yoshihiro ~~ rt (College of Hum. and Sci., Nihon Univ.):9iX fD x (Dept. Phys., Kyoto Univ.)
IEKI Kazuo
NAGAME Yuichiro 71< 13 ~lftr-g~ (Dept. Chern., Tokyo Metropolitan Univ.)§
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SUEKI Keisuke
YOSHIZAWA Shinzi E iR i§ ?5 (College of Hum. and Sci., Nihon Univ.)'***

Linac Laboratory
CHIBA Yoshiaki -T ~ H BfJGONO Yasuyuki jf!~ Jl ~ £HOSHINO Kiichi £ H *,C
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KASE Masayuki 110 i*Ji l§ £MIYAZAWA Yoshitoshi '8 iR it fii!J:
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ISHII Keishi 15 # JJ! £ (Dept. Nucl. Eng., Kyoto Univ.)
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MATSUO Takashi ~ ~(Tokyo Univ. of Agric. Technol.)
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TSURUBUCHI Seiji t~ iJrn ~URAKA WA Junji im )II JIIJt ?s (Res. Lab. for Nucl. Reactors, Tokyo Inst. Tech.)
YAGISHITA Akira m T
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KUMAGAI Hidekazu 1m ~ ~ fD
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FUJIOKA Manabu III fIli]
ISHII Keizo :;0 # ~ J1t (~yclotron, Tohoku Univ.)
MIURA Taichi -=: im 7:::. - (Dept. Chern., Tokyo Metropolitan Univ.)
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MORITA Susumu ~ ill
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NAGAHARA Teruaki 7k1m BM (lnst. Atomic Energy, Rikkyo Univ.)
NAMIKI Masatoshi jE!ft 1:3t (Div. General Education, Takachiho College)
TAWARA Hiroyuki 1*-pf Z (lnst. Plasma Phys., Nagoya Univ.)
URAKAWA Junji im )II JIIJi is (Res. Lab. Nucl. Reactors, Tokyo Inst. Tech.)*'*(Student)
HATSUKAWA Yuji M )II

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Thermonuclear Fusion Laboratory
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Solid-State Chemistry Laboratory
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KIMURA Kazuie* tt - *Radiobiology Laboratory
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