the Institute of Physical and Chemical Research
Wako-shi, Saitama Pref., JAPANIPCR cyclotron
Progress Report 1974

Vol. 8IPeR Cyclotron Progress ReportVol. 8The Institute of Physical and Chemical Research
HRIKAGAKU KENKYUSHO" Wako-shi, Saitama, 351 JAPAN
December, 1974

Editors
F. AmbeM. Imamura

M.OderaH. Sakairi

A. Hashizume

This volume contains recent information of the IPCR Cyclotron, informal reports andabstracts of papers which will be published at scientific meetings or in publications
by staff members, guests, and visitors.
All rights reserved. This report or any part thereof may not be reproduced in any
form (including photostatic or microfilm form) without written permission fromthe publisher.

CONTENTS
Page
1.

INTRODUCTION

2.

MACHINE OPERATION ............................................................................................. .

3.

MACHINE DEVELOPMENT AND ACCELERATOR PHYSICS

3- 1.
4.

Acceleration of Boron Ions in the Cyclotron2.............................................. .

4

Incident Energy Dependence of Optimum Q- Valuesin Multinucleon Transfer Reactions Induced
by Heavy Ions ............ ... ............... ..... ............................. ....... ..... ...... ...............

6

Multi-nucleon Transfer Reactions on Mo-Isotopes
by 14N at EL ~97 MeV .................................................................................. .

12Single-nucleon Transfer Reactions on
92Mo Induced by 14N and 12C ...................................................................... .

15

Transfer Reactions Induced by
14N on 12C at 79 MeV .................................................................................. .

19

4 - 5.

Analysis of Elastic Scattering of 16 0 by 19F ................................................ .

24

4- 6.

DWBA Analyses of One-nucleon Transfer Reactions
Induced by Heavy Ions on the N~28 Target Nuclei

27

4- 7.

Long-Range a-Particle Decays and Level Structure of 216Ra

30

4 - 8.

Angular Distributions of Long-Range a-Particles Emitted
from High Spin States in 216 Ra and Statistical Tensors

32

4-9.

The eHe,3He), eHe,3He'), and eHe, a) Reactions on 13C ........................ .

34

4-10.

A Study of Resonance States Induced by
160eHe, d)17F and 28SieHe, d) 29 p Reactions

40

NUCLEAR PHYSICS
Scattering and Reactions
4 - 1.

4-2.

4- 3.

4- 4.

4 - 11.

4 - 12.

58,6o ,62,64NieHe, d) 59,61 ,63, 65 CU Reactions
and the Correlation between Unbound States andResonance States .. ................ .. ........... ........ .. ...... ... ..... ... ...... ..... ..... .... ...............

44

Analyses of CreHe , d)Mn Reactions at 29.29 MeV.....................................

48

4- 13.

5.

Full Finite-Range DWBA Calculations for Heavy-Ion
Induced Two-Nucleon Transfer Reactions52

4- 14.

Two-Nucleon Transfer Reactions between Heavy-Ions ................... ...............

55

4 - 15.

One- and Two-step Processes in the Heavy-Ion Induced
Two-Nucleon Transfer Reaction ........................................ ............. ............. ...

58

4 - 16.

CCBA Analysis of (p, t) Reactions on Rare-Earth Nuclei .............. ...............

61

4-17.

Folding Model for Nucleus-Nucleus Optical Potential

64

4-18.

Role of the 12C-Core Exchange in the
160_ 12 C Elastic Scattering ... ............................... ...... ............. ........... ...............

68

NUCLEAR PHYSICS
Nuclear Spectroscopy
5- l.

5- 2.

5- 3.

5-4.
6.

73

High-Spin State Yields in 88y Relative 1+ State in
90Nb Excited via 89y'+ ex Reaction ............................................................ .... .

76

Short Life Radioisotopes and Isomers Observed via
Ir + C Reactions .. .......... ...... ...... ........ ... ..... ......... .......... ... .................... ...... ... ....

79

Monopole Effective Charges

82

NUCLEAR INSTRUMENTATION
6- 1.

Performance of the IPCR Polarized Ion-Source

84

6- 2.

Investigation of Residual Gases in the
Ionizer of Polarized Ion Source ... .......... .............. ..... ... .... ...................... ..... ...

89

Mech~'nical Design of a Polarized Ion Source
for the INS Cyclotron ........................ , .............................................................. .

93

6- 3.

7.

Lifetime Measurement of the 6+ (2976 keY) State in
46Ca and E2 Effective Charges in (1 f 7 / 2 )±2 Nuclei .................................... .. .

ATOMIC AND SOLID-STATE PHYSICS
7- l.

Inner-Shell Excitation by Nitrogen Ions and Alpha Particles (3)

97

7-2.

Positron Annihilation in Y and Nb.................... .... ........................................

99

7-3.

A Damage Function Based on the Focused
Replacement Collision Model .............. '" ........ .............................. ............ ......

101

Secondary Electron Emission from Al and Ni
by Fast-proton Bombardment ................................. ........ .............. ................

104

7 - 4.

8.

9.

RADIOCHEMISTRY AND NUCLEAR CHEMISTRY

8-1.

Charged-Particle Activation Analysis. ..... ... .............. ......... ........ .... .. ............ ...

106

8-2.

Mossbauer Emission Spectroscopy of 119Sn
after the EC Decay of 119Sb .........................................................................

108

8-3.

Behavior of Tritium and Hydrogen Atoms on Metal Surface ......... .......... ....

III

8-4.

Mass Asymmetry in the Fission of Actinide Nuclei

113

RADIATION CHEMISTRY AND RADIATION BIOLOGY

9-1.

Heavy-Ion Radiolysis of Liquid Aldehydes.... ................ ...... .......... ........... ....

118

9- 2.

Optical and ESR Studies on Single Crystals of
KBr and CdS Irradiated with Heavy Ions ....... ... ... ..... .. .. .. ..... ......... .... ... .. ......

120

LET Effect on the Radiation-Induced Polymerizationof Styrene ........................................................ ....... ........ ............. :............ ......

123

Inactivation of a Radioresistant Vegetative Bacterium
Micrococcus radiodurans by Charged Particles .. ..... ..... .... ..... ..... ........ ..... ..... ...

126

LET Effects on Production of DNA Single-Strand Breaks
and Their Repair in ~ coli Blr .... ............... .... ... ........ ........ ..... ......... ... ...... ....

129

9- 3.

9- 4.

9-5.

10.

PREPARATION OF RADIOISOTOPES AND LABELED COMPOUNDS

10-1.

11.

133

RADIATION MONITORING

11-1.

12.

Production of Radioisotopes and Preparationof Labeled Compounds for Medical Use ..... . ... .... .... ....... ....... ...... ..... .............

Routine Monitoring134

A NEW MACHINE

12- 1.

The Variable-Frequency Linac ProjectStatus at Autumn 1974 ..........................................................................

136

12- 2.

Design Study Using Cavity Models ................................................. ........ .. ......

138

12- 3.

Summary of Measurements on Electrical
Characteristics of Model Cavities I and II

139

Voltage Distribution at the Gap of Model IIwith the Drift Tubes Removed .... ... ..... ............. ............... ........... ........... ........

142

12- 4.

12- 5.

12- 6.

12- 7.

12- 8.

12- 9.

Results of Measurements on Model III of Linac
Cavity having a Stem of Circular-Shape ....................... ......... .......... ...............

144

Results of Measurements on the Model IV of
the Linac Cavity .................................................................. :..........................

146

Design of the Linac Cavity
General ...................................................................................... ...............

148

Design of the Linac Cavity
Mechanical Problems ......... .......... ................. ... ........................................

150

Design of the Linac Cavity
Cooling ... ........ ............ ....... ...... ...... ........ ... ...... ..... ... ......... ... ... .... ..... ..........

151

12- 10. Design of the Linac Cavity
Vacuum Consideration

153

1 2- 11. Distribution of Magnetic Flux Density in the
Poles of Drift Tube Quadrupole Lenses ...................................................... '"155

12- 12. A Circuit Using a PIN Diode Switch for Measurementsof the Q-values of a Cavity at High Resonant Frequencies

157

12-13. Trial Fabrication of Coils for Drift Tube Quadrupoles

159

12- 14. Effects of Non-uniformity of Voltage
between Drift Tube Gaps ......... ... ... ....... ....... ..... .......... . ........ ...... .... ..... ...... .....

161

12- 15. Computer Codes for Orbit Dynamics in the
Heavy Ion Linac ....... ............ ......................... ....... ... ...... .......... ... .. ..... ... ..........

164

13.

LIST OF PUBLICATIONS

165

14.

LIST OF PERSONNEL

168

15.

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

171

AUTHOR INDEX .... ....................... ...... .. .......................... .. ..........................................

175

1. INTRODUCTION

The cyclotron has been operated for eight years with prudent care to and constantimprovements by the technical staffs and operation crew.

Total work time of the machinereached as much as 38,000 h until the end of 1974.
As in the previous years, the heavy ion acceleration was the main mode of operation inthis year.

The acceleration of boron ions was tested and proved successful.

Experimental and theoretical studies on nuclear reactions and level structures were
continued.

Researches related to radiation chemistry and radiation biology were carried out

mainly using heavy ions.

On-line optical and ESR spectroscopy was applied to study thedifference in LET effects by heavy and light projectiles.

Charged-particle activation analysis,

production of radio-isotopes and preparation of labeled compounds for medical use were carriedout.

The analysis on the states of atomic electrons by the methods such as inner shell

excitation by heavy ions and measurements of angular correlation of annihilation gamma-rays
were made .
The development of the polarized ion source has been completed.

It is scheduled to beinstalled in the cyclotron of the Institute for Nuclear Study, University of Tokyo, in 1975 andwill be used by people of the both institutes, IPCR and INS.
The heavy-ion linac project was approved by the Government this year.

The progress of

its construction and related researches will be described in this and the following issues.
It is our great regret to announce the sudden death of Dr. H. Tahara, Chief of the Organic

Synthesis Laboratory, on January 2, 1975.

His work on the preparation of 18F-labeled compounds

greatly contributed to the field of medical diagnosis.

Hitosi Hagihara, Chairman
The Cyclotron Board

2

2. MACHINE OPERATION

H. Nakajima, K. Ogiwara, S. Fujita, K. Ikegami,
T. Kageyama, S. Kohara, and H. Takebe
During the period from Oct. 1973 to Oct. 1974 the cyclotron was operated on the 24 ha day basis. Statistics of machine operation is shown in Table 1. The working time meter onbeam which indicated 4373 h is decreased by about 13 % compared with last year. However,total days of the machine time was decreased only by 2.5 %. This difference comes from the factthat 19 days were occupied for adaptation of the machine time and the cooling period forresidual radiation in the scheduled machine time.
Requirements of heavy ion beams continued to increase and the cyclotron was operated 113
days with the heavy ion source, which was 45 % of the total days of the scheduled machine time,that is, was increased more than 21.5 % compared with last year. Table 2 shows machine time
allotments to various activities in this period.
A major part of slight troubles were: Some printed circuit cards were lost by touching withsockets, cooling pipes were choked-up with fur, and fatigued materials with cracks were found at
joints between a bellows and cooling pipes for the movable liners in the accelerating chamber.
A transition to the higher mode oscillation of the RF-system sometimes brought about
great difficulty to realize higher accelerating voltage, especially for heavy ions. Cooling system of
the movable short was changed and capability of anti-transition was improved.
Table 1. Machine operation time and day.

Date

Oscillator

Ion source

BeamOct. 23, 1973

32976 (h)35693 (h)6652 (h)Oct. 22, 1974

37715 (h)40591 (h)11025 (h)365 days4739 (h)4908 (h)4373 (h)Percent of 365 days

54.1 %

56 %50 %Schedule in this period:
Machine time249 (days)

Overhaul and installation work

49 (days)

Periodical inspection and repair

27 (days)

Vacation and holidays

40 (days)3

Table 2. Scheduled machine time and subjects of activity in the period, IX

Subject

Heavy ionLight
particles

Total

Direct reaction

1561 (h)1670 (h)3231 (h)In-beam spectroscopy

549

142

691

RI prod uction

0

84

84

Nuclear chemistry

0

433

433

Radiation chemistry

172

13

185

Radiation biology

131

80

211

Solid state physics

0

222

222

Inner atomic shell
excitation study

24

0

24

Nuclear medicine

0

192

192

Nuclear fuel study

0

121

121

RI Production

24

17

41

Development of
instruments

45

46

91

Total

2506 (h)3020 (h)5526 (h)Percent in total

45.3 %

54.7 %

100 %Nuc!. phys.

Fields otherthan nucl. phys.

Ou tside users

1I

Maintenance operation and engineering
Exchange of ion source

58 (h)

Reserved for machine time adjustment
and cooling of radiation

456 (h)Machine inspection and repair

624 (h)Total

1138 (h)4

3. MACHINE DEVELOPMENT AND ACCELERATOR PHYSICS

3-1.

Acceleration of Boron IonsInthe eyc lotron

A. Shimamura and I. Kohno
It was planned to accelerate B ions in the cyclotron.

For this purpose, the production ofmultiply-charged ions of B using the IPCR ion source was studied at a test bench, and sufficientquantities of IOB 3 + and 11 B3 + ions were obtained.

These B ions were successfully accelerated in

the cyclotron employing the following procedure.
( I ) Gas flow system
Figure I shows the gas flow system of BC 13 , which was used as the sample gas.

Since

Pressure gauge

V

Slow leak
volve

/

/

/; ~

/
/

I,
I,
II
I,

II

--/

/ I

V

Piran i gauge,;;:'--

HExhausting,....L,b=------'=-,' pip e

V

lllJ

I on source
Cyclotron vaul t

Controlroom

R.P

Ice boxFig. I. Gas flow system .
-~-~.

-

0=-

l

~ _:_-~ 11B2+ :(\JNGas : BC1 3
Arc power = 700 V , 2 . 3 A
p = 2.5 X 10- 5 Torr.

Magnetic field = 0. 6 Wb / m2

Fig. 2. A m/q spectrum of the ion beam measured at the test bench when BCI 3 gas wasfed. Arc power: 700V, 2.3A, Vac. = 2.5 x 10- 5 Torr. Magnetic field = 0.6 Wb/m 2 .

5

BC 13 is a liquid whose vapor pressure at 0° C is about 400 Torr, the reservoir of BC 13 wasdipped in ice-water.

This gas was introduced into the ion source through a slow leak valve.

gas flow system was evacuated by an auxiliary rotary pump.

The

Since BC 13 reacts with H 2 0 in

the air, the exhausted gas was discharged to outdoors using a blower so as not to make any
trouble.
(2)

The gas flow rate was measured with a Pirani gauge.
Production of multiply-charged ions of B

Figure 2 shows the m/ q spectrum of lOB and 11 B ions measured in the test bench. 1) In
the spectrum peaks corresponding to IIB+, 10B+, IlB 2 +, IO B2 +, 11B3+ and 1°B3+ ions were found. As
the yields were measured in a unit of electric current, the particle yield of B3+ ions was
one-third times that of B+ ions at the same current reading.
(3)

Acceleration of B ions

10B3+ and I1B3+ ions were accelerated in the cyclotron.

Fig. 3 shows a m/q spectrum ofions accelerated in the cyclotron when BC 13 gas was introduced into the ion source.
The spectrum was measured by varying the strength of the magnetic field at a radius of
69cm.

These 11 B3+ and 1°B3+ ions were extracted from the cyclotron at intensities of 4 /lA
and 1 /lA respectively. The energy ranges of 11B3+ and 10B 3+ ions obtained in the IPCR
cyclotron were 50 to 72 MeV for the former and 45 to 70 MeV for the latter.

(3rd)

Gas ' BCb

35C14 +

~1
1 jJ.Af = 5.947 MHz(3rd)
37 C14+~l(3 r d)35C13+~l

Vd = 5 1 kV
Arc power = 350V , 4.2 A

R =59cm
P =5.4XIO- 6 Torr.

N

E~ 500 nA

200

220

240

250 280 300 320 340
Magneti c current (A)

350

380

Fig. 3. A m/q spectrum of the ion beam in the cyclotron whenBC1 3 gas was fed to the source.

Reference

1)

I. Kohno et al.: IPCR Cyclotron Progr. Report,!, 13 (1967).

6

4. NUCLEAR PHYSICS
Scattering and Reactions

4-1.

Incident Energy Dependence of Optimum O-ValuesinMultinucleon Transfer Reactions Induced by Heavy Ions

T. Mikumo, I. Kohno, K. Katori, T. Motobayashi,

S. Nakajima, M. Yoshie, and H. Kamitsubo

We report here on the systematics of positions of the maximum in the distribution of
excitation energy Exm (B) and the corresponding Q-Values Qm (B) of a residual nucleus B, deduced
from the continuous spectra ("bumps") of b of the reactions of type A (a, b) B, and on theirdependence on Ea'

Using 14N and l2C beams and targets of f-p shell nuclei csoTi, 52Cr, 53Cr

and 54Fe), we studied nuclear reactions at energies about twice to three times higher than the
Coulomb barrier (E L = 60 ,...., 95 MeV).

The reactions studied are listed in Table 1, together

with useful experimental conditions and experimental results.

Typical spectra for 52Cr + l4N

reactions at 80 MeV at 8 L = 22° are shown in Fig. 1.
Table 1.

Multi-nucleon transfer reactions.

A=a

EL (MeV)Ei (MeV)

52Cr + l4N

95

74.9

E·1- B c
Ei/Bc(r o=1.4fm) (r o=1.4fm)
2.89

49.0

A (a, b) B.

e L (b)b measured(deg)

13C, l2C, 12B, 11 B, lOB , lOBe
16, 20, 25

9Be, 7Be, 7Li, 6Li, 4He

53Cr + l4N

90

70.9

2.73

44.6

16,25,18,22 , 27

80

63.0

2.43

37.1

18,22,27

70

55.2

2.16

29.3

22, 27

64

50.4

1.95

24.5

20, 27

90

71.2

2.74

45.0

160, ISO, l5N, l3C, l2C,

10, 12,15,18

11 B, lOB, lOBe , 9Be,
7Be , 7 Li, 6Li, 4He

24,27,30,33

50Ti + 14N

70

54.7

2.41

32.0

54Fe +14N

70

55.6

1.94

26.9

52Cr + 12C

90

73.1

2.97

48.5

lOB , lOBe , 9Be, 7Be

18

70

56.9

2.31

32.3

lOB , lOBe, 9Be

18,22

60

48.8

1.98

24.2

17,19,22,25,27

50Ti + l2C

60

48.4

2.13

25.7

25

54Fe + 12C

60

49.1

1.86

22.7

25

13C, l2C, iJ B, l6B

25
26

7

30
20
10

30
20
10
20
10
80
60
~
c

40

::J

0

u 20
60
40
20
200
100
400
300
200
100

52C r

+ 14N

80M e V

50

40

30

20

10

o

E x ( MeV)

Fig. 1. Energy spectra of l3 C, 12C, liB, lOB, 9Be, 7Li and 6Li particles
emitted in the 52Cr + 14N reaction at an energy of 80 MeV anda laboratory angle of 22 degrees.

Note first the following characteristic features about the Qm (B) of reactions, in particular,
52Cr + 14N (E L = 95 , 90, 80, 70 and 64 MeV) and 53Cr + 14N (E L = 90 MeV) which weremost widely studied.
(1)

For incident c.m. energies Ei considerably higher than the Coulomb barrier Bc for thea+A system, the spectrum shape of b is mainly characterized by a continuous bell-shaped form(bump).

The shapes of bumps are very asymmetric for smaller n, the number of transferred

nucleons, while they approach symmetric forms for the larger n.

Further insight of the energy

spectra of 53Cr + 14N at 90 MeV at various angles reveals the existence of two components inthe bump (with b = 13C, 12C, liB, lOB): a higher energy part (hard component) and a lower
energy part (soft component), the peaks of which are separated by ;::: 10 MeV.
presumably, to "quasi-elastic" and "deep-inelastic" processes,t) respectively.

They correspond ,In the angular range

8

investigated (8 L == 10 - 33°). the relative intensity of the hard component is higher at forward
angles, while that of the soft component higher at larger angles.

We discuss separately about

the characteristic features of their angular distributions and the absolute yields.

Following

discussions are concerned with the systematics of peak positions of overall bumps.
(2)

The spectrum shape does not reflect the structure of target nuclei sensitively.

For

instance, the spectra of 52Cr + 14N -+ 54Mn + 12C and 53Cr + 14N -+ 55Mn + 12C are quite
similar in shape at the same bombarding energy.
In general, IQm (B) I increases with an increase In n for a given incident channel(Fig. 2) as reported elsewhere. 2) The accuracy of the values of Qm is, in most cases, within(3)

about ± 2 MeV.
(4)

Qm (B) varies very slowly with 8 L , angle of emission of b , and often remains almost

constant throughout a wide range of 8 L investigated , especially in S3Cr + 14N -+ 55Mn + 12C
o~--~--~----~--~---,----,----,---,,---,---~----------~o 16°(f)16 o(53Cr )® 25 °

o 22°
•

27"

o 20°
• 27 °- 5p5n- 50 L---~--~----L----L--~----~---L--~,---~--~----------~

o

23

4

5

6

n ( number of t ransfer! 2d nu c l eons )Fig. 2. Qrn vs. n (number of transferred nucleons) curves for 13C, 12C, 12B, II B, lOB,
lOBe , 9Be, 7Be , 7Li, 6Li and 4He particles emitted from the 52Cr + 14N
reactions at energies of 64, 70, 80 and 95 MeV , and the 53Cr + 14N reaction
at an energy of 90 MeV.

9

/,'

- 10

- 20

>

Q)

~ -30
E
Gf

- 40

- 50

53 C r+ 14]\'

90 MeV2030

40

8 1. ( cleg )Fig. 3. Qm vs. 8 L (detected laboratory angle) curves for 13C, 12C,
II

B, lOB and 9Be particles emitted from the 53Cr + 14N

reaction at an energy of 90 MeV. For II B, lOB and 9Be
hard and soft components are not separated.

with a very high Q gg value (+ 5.28 Me V), Q gg being the Q-value of the reaction leaving theboth final products in the ground states.

This situation is shown in Fig. 3 in contrast withthe cases for sub-Coulomb or near-Coulomb reactions, where Exm (B) is strongly dependent on
8 L ·3 )(5)Absolute yield of the peak of the bump is strongly dependent on Q gg values among

the isotopes studied.
We now discuss the systematics of peak positions of bumps.

If we plot Qm values as afunction of n, we obtain an almost linear reaction,

until n reaches a certain number of transferred nucleons no , as shown in Fig. 2.
and 53Cr + 14N (E L = 64 '" 95 MeV), noenergies.

For 52Cr + 14N= 5 is at higher energies, while no = 4 at lower

The vlues of Q'S are found to be almost proportional to Ei in 52Cr + 14N reactions,giving a relation:
In these cases Q = -(5 '" 8) MeV/nucleon and ~ varies with a, but is nearly independent of Ei ·These relations hold in either of the proton and neutron transfers; in other words, for thesame a, adjacent A and a given E i , Qm,s are almost the same for a given n (between isobars of
products b), e.g., in 12C and 12B, lOB, and lOBe, 7Be and 7Li (despite large differences in Ex m (B)between isobars of the residuals B).
These characteristics are interpreted as follows: Qm is rewritten as

10

G I . = 20°
0- _ _
- 10

22 °
18°
16°
16 °
- - -0 - - - - - - - - - - 0 - - - - - - - - ---0-- - - -0 13C
0 - - - - - _0 __

0 -_
- 20

- --0____----_

1:::::. ......

..... .....

\7. . . . ::.:.....................
- 30::.-O.l~ - 40-.."""- . . . . -...0 - - -e __ .......... _~=---- - - - - -0 - - - - -0 lIB
X-_~~~-... ----==~~~D--_+- _- • .:::-\7- - - - -6. __@............

----+ -::::::::::::--- - ___ --::::::::::,__'.......

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

......
'©-

- 50

- 60

----0---------- 0 - - - - -0 12C__------ --\1<. ..........---""""6.

- ...... +--::.::-::::--__-_..::: __ •--..... -- - - _.................. \1 9--- --- ----@....

+ 14 :\

8e--_+_ -.....--_::...', 7L'Be- -- ,r:::::..-:..- - _7i.......... -+6L i...................... @52 C,.

lOB..........
.............@

4

He

- 70

60

70

80
EL

100

90

( l'vle \ ' )Fig. 4. Qm vs. E j (incident energy of projectiles) curves for l3C,
12C, lIB , lOB , 9Be, 7Be, 7Li, 6Li and 4He particles emitted
in the 52Cr + 14N reaction.
where Ef is the mean c.m. energy in the outgoing channel and 6E is the total energy loss.
The linear relations like Qm = an + ~ and a = 'Y Ei + 0 reflect the fact that a constant amountof energy is lost per nucleon transfer as long as n is not too large, and this constant rate ofenergy loss is proportional to the incident energy.

If Ei-Bc is large enough, say ~ 30 MeV, theenergy loss per nucleon is almost constant until n = no ;::: 5.

For the transfer of nucleon

number n beyond no, the residual energy of the penetrating particle becomes no more enoughto continue to transfer the same amount of energy, or some other reaction mechanism becomes
more important.

Hence the linear relation is broken down and Qm is saturated against n.

Such a saturation begins at smaller no for smaller Ei-Bc values.

The segment of linear line, ~looks to reflect the energy loss of the incident particle a in the nuclear matter A due toinelastic processes.
Turning the eyes to the transitions for larger n, say n ~ 7, we should remark the following
points:1)

Qm vs. n deviates largely from the linear relation.

2)

Qm vs. Ei has a steeper gradient.

The largest gradient is seen with 4He, where thepeak energy value of the outgoing particle b is almost independent of incident energy.
3)

The shape of the bump approaches a symmetric form.

4)

The peak cross section a m increases with increase of n, attaining a very large value

for 4He.
These facts suggest the presence and the importance of reaction mechanism other thanthose discussed above.

11

The studies on the systematic features about Qm, together with the absolute cross sections
and angular distributions, may throw light on the elucidation of the mechanism of multinucleon
transfer reactions.

References
1)

D. H. E. Gross and H. Kalinowski: Phys. Lett., 48B, 302 (1974); A. G. Artukh,
G. F. Gridnev, V. L. Mikheec, V. V. Volkov, and J. Wilczynski: JlNR E7-6970, Dubna(1973); J. Wilczynski: Phys. Lett., 47B, 484 (1973).

2)

T. Mikumo, 1. Kohno, K. Katori, T. Motobayashi, S. Nakajima, M. Yoshie, and H. Kamitsubo:
Proc. lnt. Conf. Reactions between complex Nuclei, Nashville, 1, 64 (1974).

3)

N. Anantaraman, K. Katori, and J. P. Schiffer: Proc. of "Symp. on Heavy Ion Transfer
Reactions", Argonne National Laboratory, PHY-1973B, 413 (1973); W. von Oertzen:
ibid., p. 675 (1973).

12

4-2.

Multi-nucleon Transfer Reactions on Mo-Isotopes

by 14Nat E L = 97 MeV

M. Yoshie, H. Kamitsubo, K. Katori, I. Kohno,
T. Motobayashi, S. Nakajima, and T. Mikumo
Multi-nucleon transfer reactions between heavy nuclei sufficiently high above the Coulomb
barrier have attracted much attention in connection with the reaction mechanism.

Systematic

data presented by the DUBNA group!) show quite interesting behavior in the cross sections,which depend on the reaction Q-values (Qgg) regularly.

Discussions on this regularities andtheir interpretations are found in the literature.}) Also, Q-values which give maximum crosssections in the energy spectra were interpreted considering the reaction kinematics. 2 )Particle production cross sections of He, Li, Be, B, C, and 0 isotopes in the bombardmentof all the stable Mo-isotopes by 14N projectiles supplied by the Cyclotron were measured at
EL = 97 MeV at two angles () = 25° and 30°. Conventional counter telescope systems wereused to identify the particles. Self supporting targets had the thicknesses from 0.45 to 1.0
mg/ cm 2 . The overall energy resolution was 1 MeV in the worst case. Particle yields werenormalized to the forward angle elastic scattering yields measured with the same counter togive the absolute values of production cross sections.
By varying the targets from looMo to 92Mo, Qgg changes its value appreciably for a certain
reaction, which makes it possible to study the dependence of the cross sections and thespectrum shape on Qgg. On the other hand, it is expected that the angular distributions of

- 5

- 10

- 15

Q gg ( l\leV )Fig. 1. Production cross sections of B-isotopes in bombardment of
Mo-isotopes by 14 N at EL = 97 MeV. The numbers in the
figure are the mass numbers of the targets.

13

products do not suffer much changes from the classical estimates.

So, the cross sections

measured at certain fixed angle are good measures of total cross sections if one type ofejectile is considered. As an example, production cross sections of B-isotopes are plottedagainst Qgg in Fig. 1. The yields of lOB and 12B are each on one line, whereas the crosssections of lIB from the odd mass targets are slightly smaller than those from the even mass
targets.

Note that in the former case the neutron numbers of the target residues are evenfor even mass targets and odd for odd mass targets, whereas the situation is opposite in thelatter case. This fact may be due to the effect of the pairing energy.
To characterize the bell-shaped energy spectrum, three Q-values were defined as follows:
one is the Q-value which gives the maximum cross sections (Qm), and the remainning two arethose for which each cross section is a half of that at Qm. These three Q-values are shown
also for the B-isotopes in Fig. 2.
nallower.

As the target becomes lighter, the spectrum becomes

Despite the large changes in Qgg' the Qm remains rather constant, which indicatesthe importance of reaction kinematics.

~las~

number of thp

12 Htar~('l

II I>

100 9897969594

92

100 9897969594

IIJ II92

100 9897969534

92

l) ""

- 10

01

~-

~25O

- 20

() '"

• 30

"--"'-0-."0.-----------

@~

."-..

@~

~\ __ A25 °

~30 °

~~

30

~

li~30'
p ..
•

25 '

- 40

?.

~

- 5 0 ' - - - - - - - - - - -- - ------""-- -- - - 'Fig. 2. Three Q-values which characterize theenergy spectra of B-isotopes with Qgg
are plotted against the mass numbersof the targets. Energy spectra havemaxima at QID and f' = Q1 - Q2 gives
the FWHM.

14

References
1)

A. G. Altukh, G. H. Gridnev, V. L. Mikheev, V. V. Volkov, and 1. Wilczynski:

Nucl.

Phys., A211 , 299 (1973) and the references therein.
2)

P. J. Siemens, J. P. Bondorf, D. H. E. Gross, and F. Dickmann: Phys. Lett., 36B, 24(1971).

15

4-3.

Single-nuc leon Transfer Reactions on 92Mo Inducedby 14Nand 12C

M. Yoshie, K. Katori, I. Kohno, T. Mikumo,
T. Motobayashi, S. Nakajima, and H. Kamitsubo

In order to elucidate the validity of the semi-classical and DWBA theories, single nucleon
transfer reactions on 92Mo by l4N and 12C were studied. l ) Beam energies were 97 and 75 MeV
for 14N, and 90 and 60 MeV for 12C ions. Conventional counter telescopes were used to detect
the emitted particles and the data were recorded on a magnetic tape event by event for later
analyses.

A self-supporting target of 450 f.1g/cm 2 was used and the typical energy resolution was

400 keV.
Angular distributions for four transfer channels were measured in the 14N induced reactions,and only the proton transfer was studied in the 12C induced reactions.

The angular distributionsof elastic scatterings were also measured, and these data were analyzed with the optical modelusing a search code. 2) Representative parameter sets are listed in the Table 1.
Table 1. Optical potential.
SystemEL (MeV)V (MeV)W (MeV)ro (fm)a (fm)

rc (fm)92Mo + 14N

97 (75)94 (117)

25

1.15

0.5

1.2

92Mo + 12C'

90 (60)120 (127)

25

1.13

0.5

1.2

92Mo + lIB

70

100

25

1.15

0.5

1.2

Optical potential parameters which are found under the constraints rR = r I = r o' aR = aI = a.
Energy dependence is explained by varying the depth V.

Single particle levels studied by the light-ion transfer reactions 3 ) have also been observed in
the present study.

Two different projectiles made it possible to study the effects of kinematicalmatching conditions, that is, the l2C induced reactions have large negative Q-values comparedwith those of l4N induced reactions, and only the high spin levels are favored III the former case.
As an example, energy spectra of neutron stripping reactions are given in Fig. 1.

e2C, llC) reaction, d

5 /2

and Sl/2 states are suppressed.

In theThe semi-classical theory developed byBrink4) reproduces the data well at least qualitatively.
The angular distributions are shown in Fig. 2, together with the theoretical cross sections
calculated using the exact finite range DWBA code developed by Tamura and Low.S)

Since thefirst excited states (Pll2) were not resolved from the ground states (g912) in the proton transfer
reactions, the DWBA fits were made using the following formula:

~

do I
= N
C 2 S(I) C 2 S(2) do I
dn expostatesdn DW ,

16

92Mo ( 12 C, l1C )93 Mo

EL = 90MeV

50

d3/2~ ~ 97/2

40

dSI2

t

2i 30

=
u

"-

~
c:

~

h11l2

Q)

c:

20

=>

o

u 10

140
92 Mo (1 '1.J , 13 N ) 9 3 M0

120

[L =

97 MeV9712

S1/2(1.36)(0.95)

dSI2 grnd

Bt = 25°

100
Q)

c:
c:
0

80

is

hl1!2

"-

(2 .32).....c: 60
II>

=>

0

u

40
20

Ex (MeV)Fig. 1. Energy spectra of neutron stripping reactions on 92Mo by 14N
and 12C. The same states in 93Mo are populated in bothreactions, but the peak strengths are different from each other(see text).
where C 2S(l) and C 2S(2) are the S'-factors of the heavy system found in the references 3), andthose of the light system calculated by Cohen and Kurath. 6 )N is a normalization factor.

The transferred nucleon was assumed to be bound in a potential well of Woods-Saxon form witha radius of R = 1.2A 1/3 and the diffuseness a = 0.65 fm, where A is the mass number of thecore nucleus.

The well depth V was searched around 60 Me V to give the actual binding energy,

and V LS was 7 MeV. The N-factor defined above varied from 0.5 to 0.8 case by case in thecalculations on the angular distributions to ground state groups of the residual nuclei inducedby 14N.

Incident energy dependence of the magnitudes of the cross sections was well accountedfor.

e C, llB) and e C, 13N) reactions shown in Fig. 2 had N-factors of about 1.7 and 0.9

The

2

2

respectively, which are slightly larger than those in the case with 14 N.

In the proton transfer

reactions, positions of the angular distribution maximum differ by a few degrees between stripping
and pick-up, whereas in the neutron transfer reactions it does not. The DWBA theory explainsthese differences reasonably well.

17

10100

40°

30°

20·

30·

20"

9~o+ 14N 97 MeV(14N , 13 N) 93Mo

40°
92Mo

+ 12C 90MeV(12 C ,l1S)93Tc~

2d 5/2 grnd

(I/I"

19 9/2 grnd

+2p l/2 0.396

~\
Q

1\

1

I 99/2 grnd

(14N,150)9INb

Q~

\

I \2
9
, ~VfJ/\
199/ 2 grnd
+2p1/2 0.100

!v
1f
0.1

!/I~!"~
I)f+ 2M 0.100

1f

t

\

!

t~t t

Lf/
\

A(0,
L,
"c I "To(12c,13N) 91Nb
19912 grnd

~

f

t.

199/2 grnd

+2PI/2 0.396

8 o.m.

Fig. 2. Angular distributions of single nucleon transfer
reactions on 92 Mo by 14 Nand 12 C obtained by the
DWBA calculation (solid lines). Incident channel
optical parameters given in Table I are also used
for the exit channel.

In the ( 12 C, liB) and (l2C, 13N) reactions, the calculated angular distributions take always
backward positions compared with the experimental ones.

For the (l2C, lIB) reaction, the useof the exit channel parameters which reproduce the elastic scattering of liB on 92Mo does notremove this discrepancy.

References
1)

M. Yoshie, K. Katori, I. Kohno, T. Mikumo, T. Motobayashi, S. Nakajima, and H.
Kamitsubo: Proc. Intern. Conf. on Reactions between Complex Nuclei, Nashville,
North-Holland, Amsterdam (1974).

18

2)

T. Wada: IPCR Cyclotron Progr. Rep., b 87 (1968).

3)

R. L. Kozub and D. H. Youngblood: Phys. Rev., C4, 535 (1971); J. B. Moorhead and
R. A. Moyer: ibid., 184, 1205 (1969); R. L. Kozub and D. H. Youngblood: ibid., C7,
404 (1973); R. Chapman, J. E. Kitching, and W. Mclatchie: Nucl. Phys., A196, 347 (1972).

4)

D. M. Brink: Phys. Lett., 40B, 37 (1972); N. Anyas-Weiss, J. Becker, T. A. Belote, J. C.
Cornell, P. S. Fisher; P. N. Hudson, A. Menchaca-Rocha, A. D. Panagiotou, and D. K. Scott:ibid., 45B, 231 (1973).

5)

T. Tamura and K. S. Low: Compo Phys. Commun., (in press).

6)

S. Cohen and D. Kurath: Nucl. Phys., A101, 1 (1967).

19

4-4.

•

Transfer Reactions

Induced

14

by

N

12

on

C

at 79 MeV

T. Motobayashi, 1. Kohno, S. Nakajima, M. Yoshie,
K. Katori, T. Mikumo, and H. Kamitsubo

Transfer reactions induced by 14N and 12C on (f-p) shell nucleP) and heavy nucleF) havebeen reported previously.

In these cases multi-nucleon transfer reactions showed only a "bump"in the energy spectrum.

Because of large level densities together with the rather poor energy

resolution (400 - 600 ke V) we could not see any transition to a certain level of the residual

E = 79MeV
Eh=10.3°200

100

0.0 (312-)

.

.1\
.. N

.

...~ :::....~ ":.<" j '\.~..J.,...:.'. ~~::..,:....,....,...
....• ,.......
..~..~.
" ".(112+~
2.3J.·"0-(

OL....-_ _ _ _ .':·:::i-•• ',: " '.

."contom i/.}. .
\;/v..; ',:..

en......
C:::JoU

Fig. 1. Energy spectrum of reactions 12C

e N, I3C) 13N and 12C e N,
4412C) 14N. lOA MeV and 13.2 MeV peaks in the reaction 12C

e N, 12C) 14N are expected to be populated due to the4

excitation of both 14N and 12C(4A3 MeV 2+).

If)

...:

10

\

.'./

St .m ,'+'+-f--+'+

0.0 MeV

12C(14N , '5 N)"C'._.-., .
3.85 MeV (5jz+)'2C('4N ,'3 N) 13C'.'.

3.56 MeV (5/2+)

12C(14N,'3C) 13N......... -.

+,,,,T"';,.

'+\

'+-+

\

'.

...

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

.,

\

'\

.'......\\ ....

\'-'a.,....\\.

+14N 79 MeV.'.'.,.'.......

\ .,

.'.,

.,

12C

\.-.~ \

'.

+\

+,+..

....

+

'.

\

.

\/

\

.r+\

+

+\ ,+

"

••

Sc.rn,

\

,+++\

\

,. ••

"-.'+

._.

\,-

\

J T, ,,+ \ l..,. . .

•

+.

I'

+

W=20
r = I.35
0=0.25

0.0 MeV

4.43 MeV ('2C* 2+)

12 C( 14N , '2C) 14N

2.34 MeV (1/2+)

12C( 14 N, 13C) 13N

V = 65 MeV
rR=1.21 fm
OR =0.48 fm

Elastic scatter ing...
{\ '. i··. /.-.'. .

\\+,+-+/+\\.-.\+14N 79 MeV

13 N(s 1/ 2 ), and two-nucleon transfer reaction

13C and pick-up reaction 12CC4N , lSN)llC.

of Ref. 7 .

line is calculated using the optical potential

12CC4N, 12C)14N. For elastic scattering, solid

one-nucleon transfer reaction 12 CC 4 N, 13 C)

Fig. 3. Angular distributions of elastic scattering,

a

0.1

0.5

~ 0. 1~........

E

~ 0.5

0.1

0.5

12C

reactions 12CC4N, 13C)13N and 12CC4N , 13N)

Fig. 2. Angular distributions of one-nucleon stripping

a

0.1

0.5

0.05

"........b
"

~

E

.D

"-

5

5

10

N

o

21

nucleus.

We have done an experiment on transfer reactions induced by 79 MeV 14N on 12C, forlight nuclei having relatively low level densities. In the experiment 14N4+ beams provided by the
IPCR cyclotron were used.

A L1E-E counter telescope was used to identify emitted particles.

Signals from the L1 E and E counters were processed by parallel analog-to-digital converters(A.D.C.s).

Signals from A.D.C.s were stored event by event on a magnetic tape using a DDP-124

computer.

After the experiment, the data were analyzed by means of Goulding-type mass
identification formula. The target was of 12C self-supported foil about 70 pg/ cm 2 thick. Theenergy resolution was 350 - 500 keV.
One-nucleon transfer reactions
The spectrum of the 12C C 4N, 13C) 13N reaction is shown in Fig. 1. Like transfer reactions(I)

on heavier nuclei, the peaks corresponding to low lying states of 13N are prominent.

Angulardistributions of some one-nucleon transfer reactions are shown in Figs. 2 and 3. For the angular
distribution for the 2.34 MeV (1/2+) state in 13N excited by 12C C 4N, 13C) 13N, its diffraction
pattern is out of phase to that of elastic scattering shown also in Fig. 3.

The diffraction

modeP) indicates that this phasing is due to the even-L transfer, whereas the transfer reaction
by 14N is expected to populate the S1 /2 state with L = I, because' the transferred proton is in
the P1l2 orbit of 14N. This discrepancy has been also found by the Berkeley group4) for the
12C C 4N, 13N) 13C reaction through which the 3.09 MeV (SI/2) state in 13C (the analogue stateof the 2.34 MeV state in 13N) were excited.
(2) 12C C 4N, 12C) 14N
The spectrum for the two-nucleon (d) transfer reaction is shown in Fig. 1.
some selectively excited peaks even at higher excitation energies.

We can see

This is very different from

It is also remarkable that the 4.4 MeV state in 12C is stronglyThis means that d+ 12 C (4.43 Me V) is more likely than d+ 12 C (0.0 MeV) as the structure

the case of heavier targets.
excited.

of 14N or the coupled channel effect of the excitation of 12C (0.0 MeV) to 12C (4.43 MeV) is
important.

Ex
0
6.04
6 .13
6.92
8.87
9.84
10.36
' 6.1 3 (3- ) 11.1
.6.04 (O-t ) 13.9
14.7

14 ,7 (6+) ?
139( 4-t) ?
.
1( 1 (41" )E = 79 MeV

30

.1'

"
I~ .
!~9.84,, . ......
"': '.' ':'."' .:..',,'.. .\~IIJ. .\'il(r~2~\) ·1

~ 20
o

u

10

: 10361:'~21 2':.:;. -!::... :,.:::::.. ,:./;:.... .
...,...
'. '. '. :.•.. _ '::'.:

1j·-:-·r .<.-:.' li!j.:1)\\'..:' I~\,~..... .' ......
'

~

\

r

Main
(7)
configuration

O-t

OP-Oh
4P-4h
TP- l h4P-4h
1 P- l h

0+
T

r

22-t
4+ 4P - 4h
4+4i"
6-t (2P-2 h)

0.0 (0 +)

n

0 L-~
10~
0--------~~~2~0~0------------~3~0~
0 ------------~~----~~--~~-

Chan nels

Fig. 4. Energy spectrum of the 12CC4N, I°B) 16 0 reaction. Excitation energies, J11" , and apossible configulation 8 ) of 16 0 are indicated.

22

(3)

12C

e N, lOB) 16 0
4

The spectrum of the 12C
were identified.

e N, lOB) 16 0 reaction is shown in Fig. 4. Many states in 16 0
4Compared with other data on a-transfer reactions,s),6) the excitation of (4p - 4h)states is rather weaker.

This indicates that thee N, lOB) reaction is not so dominated by the

a-cluster transfer process as in case of (6Li, d) or

4

e C, BBe). Angular distributions for 6.05 MeV
2(0+) + 6.13 MeV (3 - ) and 6.92 MeV (2+) +7.11 MeV (3-) (mainly 6.92 MeV) are shown in
Fig. 5.
12C( 14N, 10 8) 16 0

ELab =79MeV

0.5

0.1
~ 0.5
(/)

.........

+

.0

E

++
+ .++

~
'-.. 0.1b-0Ex~7MeV+++ + .".
+' ••• '

(2++ 1-)

0.5

o

10

20

30
Bc.m .

Fig. 5. Angular distributions of the 12Ce4N,
IOB) 16 0 reaction.

References

1)

I. Kohno, S. Nakajima, I. Yamane, M. Yoshie, M. Odera, and H. Kamitsubo: IPCR
Cyclotron Progr. Rep., ~, 23 (1972).

2)

T. Motobayashi, I. Kohno, S. Nakajima, M. Yoshie, K. Katori, T. Mikumo, and H. Kamitsubo:
ibid. , 2, 32 (1973).

3)

K. R. Greider: "Nuclear Reactions Induced by Heavy Ions", North-Holland, Amsterdam,p. 217 (1970).

23

4)

R. M. de Vries, M. S. Zisman, J. G. Gramer, K.-L. Liu, F. D. Becchetti, B. G. Harvey,
H. Homeyer, D. G. Kovar, J. Mahoney, and W. von Oertzen: Phys. Rev. Lett., 32, 680(1974).

5)

K. Meier-Ewert, K. L. Bethge, and K.-O. Pfeiffer: Nucl. Phys., A110, 142 (1968).

6)

G. J. Wozniak, H. L. Harney, K. H. Wilcox, and Joseph Cerny: Phys. Rev. Lett., 28, 1278
( 1972).

7)

I. Kohno: Sci. Papers I. P.C.R., 68, 38 (1974).

8)

G. E. Brown and A. M. Green: Nucl. Phys., 75, 401 (1966).

24

4-5.

Analysis of Elastic Scattering of

16

0

by

19F

T. Motobayashi and B. Imanishi

When there is a large probability for a nucleus B to be represented as a composite of two
nuclei a and c, an exchange of the nucleus a is expected to be very important in the interaction
between Band a. l ) We analyzed elastic scattering of 160 by 19F by the coupled channel method 2)
considering the exchange process of 160-core.

In this analysis the FACOM 230-75 computer of

I.P.C.R. was used.
If we consider only the direct and transfer channel , and also neglect the spin-dependent

force , the total wave function of anguler momentum L is written as

where rand R represent the co-ordinate vectors between B and a, and between band c,
respectively (Fig. 3) , andr = 1~ I ' N is the number of constituent nucleons of core a or b, anda (- 1 )N-factor appears through the exchange of the nucleus a and b. Substituting this wave
function into the equation ,we obtain the equation for u(r) ,f E- (- ~~ + ~ L (L + l ) + U (r)) } u(r)1
2 f.1. dr2
2 f.1.
r2+ {E_ (_ ~~ + LL ( L + l ) + U (r))} \J dr ' K (l )( r , r , )u ( r ' )2 f.1 dr 2
2 f1
r2

+ Jdr
\

'{

K ( 2 ) (r, r ' ) - U ( r ) K (1 ) ( r, r ' ) } u (r' ) = 0 ,

(1)

where

K (1 ) ( r, r ' ) = ( _l )N Jrr ' ~ dr dT' ¢ ( r, R )¢ ( r; R' )K (21( r,r' ) = (- 1 )N Jrr , ~dr dT' ¢ ( r , R ) ! Vab (x ) + Vac ( R' ) }¢(T',R ) ¢ (r,r' )and J is the lacbian for co-ordinate transformation (f, R) to (f, r'), and U(r) is the opticalpotential between Band a. K(2)-UK(l ) is the exact DWBA form factor in the post-form, andK(I) is called non-orthogonal kernel.

As K(l) and K(2) in Eqn. (1) are both non-local operators,

it is time-consuming to solve it for computer calculation.

We have first made the calculation ofheavy ion approximation (H.I.A.) which is not so time-consuming.

In order to consider theeffect of K(1) to some extent, we solve the equation for vCr) obtained by the transformationv = y' I + K( 0u.

If the terms of the order (K(I))2 or higher are neglected, the equation of

25
Recoi I effect. ..........

H.l. A.

Wit h re co i I---- H.l. A.

+'•...-+-.

~.

+ - •.• ~21.4 MeV++ +-+-+-+----

O.S

O. S

Optictica l potential
V =SO MeV O1F0.444fm
W = 10 MeV 0r= 0 .360 fm

rR = 1.3Sfm

O. I I--------------~~-----

rr = 1.37 t m

V\:::ev~ O.S"b

0 .1 ~------~~---------bound stat e (16 0 + t )OOS-

1.3 fm o=0.7 f m(c.f. p. =O.S )--- - 2.0 fm O=0.6Sf m( cf. p. = 0.2 )0 . 01~-----------~~~r-~~·8 c.m.

90

60

30

Fig. 2. Full recoil calculation (solid lines) is
compared with H.I.A. calculation (dashed

8c.m.

Fig. 1. Angular distributions at E = 21.4, 25.8,

lines) . For each case the same value ofand 32.0 Me V. The parameters of thecoefficient of fractional parentage is used.

optical potential are decided so as to fit

Coupledto the data of forward angle scatterings

ch annel (H.IA )2S .8 MeV

where the transfer process is negligible.

bS( ar=llfm=08 1mViS = 66 MeV_................... -~,....
.......

O.S\

cf p =04.'.

...

- ---no couple

~

\

.v..\

..(\;~O.Sb

Fig. 3. Co-ordinate vectors of thesystem. In our case , c istri ton, a and b are both
160, and B = (c+b) = (c+a)

is 19F.

8 c.m.

Fig. 4. Angular distributions of elastic and inelastic
scatterings obtained by the coupled channel
calculation. The calculated values of theinelastic scatterings are multiplied by 20.

26

H.I.A. is[

E - {_L~ + L L (L+l) +U (r)2 f1 dr2
2 f1
r2

+

1
(K (post) + K (prior ) \J l + K (l )2
J J l + K (l))]V(r)= 0,

where K(post) and K(prior) are exact no-recoil DWBA form factors in the post· and prior-form
respectively.
The cross sections of H.I.A. calculated are compared with the data in Fig. 1. Data at 32
MeV were obtained by Kyoto University group ,3) and data at 21.4 and 25.8 MeV were obtainedusing the tandem Van de Graaff accelerator at the University of Tokyo.

In this calculation 19F

is considered to be 160+t, and the potential of Woods-Saxon type was used for the interaction
between 16 0 and t. Two kinds of parameter-sets (which were chosen to reproduce the binding
energy of 19F) were used for this potential, and both sets gave good fits to the data.

This

indicates the importance of 160-core-exchange process and the insensitivity of the nuclear interior.
Coefficients of fractional parentage (c.f.p.) for 19F = 160+t obtained are in good agreement withthe results of the LCONO method obtained by the Hiderberg group.4)
However, a full recoil calculation for solving exactly the Eqn. (1) gives a conclusion different
from the result of H.I.A. In Fig. 2 the results of full recoil calculation are compared with thatof H.I.A. This indicates that the calculation of H.I.A. overestimates the transfer amplitude. Thisstrong recoil effect is due to the fact that the transferred particle (triton) is rather heavy
compared with the case in which the transferred particle is a nucleon. 5)
We also have calculated the cross sections for the inelastic scatterings by the coupled channel
method (H.I.A.).

We took into account the couplings between the ground state 0/2+), the0.2 MeV-state (5/2+) , and 1.5 ~1eV-state (3/2+) of 19F. These states are assumed to have theC60+t)-structure, and two kinds of the reaction process were considered. One is the inelastic
process arising from the excitation of 19F by the interaction between triton in 19F and projectile
16 0. The other is the transfer process in which triton is transferred to projectile 16 0 to form
the excited state of 19F. The results are shown in Fig. 4. Though the diffraction phase is thesame as that of the experimental results, the absolute value cannot be reproduced by thecalculation above (the calculated value is about 20 times smaller than the experimental value).
References
1)

G. M. Temmer: Phys. Lett., 1, 10 (962) ; W. von Oertzen: Nucl. Phys., A148, 529 (970).

2)

B. Imanishi: Proc. of Symp. on Heavy-Ion Scattering at Argonne, .ANL-7837, 295 (971).

3)

K. Fujii et al.: Private communication.

4)

A. Gamp, H. G. Bohlen, M. Feil, N. Marquardt, W. von Oertzen, and R. L. Walter: Proc.
of Symp. on Heavy-Ion Transfer Reactions at Argonne, Argonne Physics Devision Informal
Report, PHY -1973B, 503 (1973).

5)

B. Imanishi, H. Ohnishi, and O. Tanimura: Proc. of Conf. on Reactions between Complex
Nuclei, 1, 25 (974).

27

4-6.

DWBA Analyses of One-nuc leon Transfer Reactions Induced
by Heavy Ions on the N= 28 Target Nuclei

S. Nakajima, 1. Kohno, and M. YoshieThe

e4N, 13e) reaction has been studied on a 52Cr target at incident energy 70 MeV. Angular

distributions of the cross section for several transitions were analyzed by the exact finite range

DWBA code SATURNMARSI. 1 )Optical model parameters listed in Table 1 were obtained from fitting to the 52Cr + 14N
elastic scattering data. Though the set ill did not give a good fit to our data, it is currently used
to explain the ct 6 o, ISN) reactions on the f-p shell nuclei. 2 ) The same parameters were employed
for both the entrance and exit channels except the set IV, where those for the exit channel weretaken to fit the elastic scattering of 52Cr + 12 C at an incident energy of 60 MeV.
52Cr(14N .13C) 53Mn

Einc. =70MeV, E(=(O.OMeV)

10

1.2

.,
~

't)

.......

1.4

ro

00

114

0,5 )

11.3

0.5 )

11.2

0.5 )

III

05 )

11.0

0,5 )

.g

11.2 7 0.67)
11.20 0.65 )0 .1

11.20 0. 50)
1120 0.35)
0.2

04 0.60.8

00

11.20 0.30)
0

20

40

60

ec,m. I deg )Fi~. 1.

Influence of the optical parameter set on the
angular distribution. The bound state parameters
are ro = 1.25 fm and a o = 0.67 fm.

28

Table 1. Optical model parameter sets used in calculation.

V
(MeV)

W
(MeV)

rR
(fm)

rl
(fm)

aR
(fm)

aI
(fm)

Set I

60.0

8.0

1.02

1.18

0.70

0.52

Set ill

100.0

40.0

1.22

1.22

0.49

0.49

entrance

60.0

11.1

1.02

1.18

0.70

0.52

exit

60.0

18.25

1.04

1.18

0.78

0.56

100.3

40.1

1.12

1.09

0.52

0.56

Set IV {Set V

The results of DWBA calculations using these parameters are shown in Fig. 1. The proton
bound state wave function was obtained from a Woods-Saxon potential with r 0 = 1.25 fm andao = 0.67 fm. The results of DWBA calculations were highly sensitive to the choice of theseparameters.

The set IV reproduced satisfactorily the experimental angular distribution in shape

but its magnitudes were more than 5 times as large as the experimental values. As is shown in
Fig. 2, it is possible to reduce the absolute strength by using smaller bound state parameters.

52Cr(14N,13C )53Mn

E,nc .= 70MeV , E.=(O,OMeV)

10

0.1

,
"

o

ill

40

20
Bc.m ( deg .)Fig. 2. Influence of changing the bound stateparameters on the angular distribution.
The optical potential parameter set IV
was adopted in calculation.

60

29

On the other hand, the set ill reproduced proper magnitudes with the standard bound stateparameters (r° = 1.25 fm, ao = 0.67 fm). Contributions of the interior of nucleus to the resultsof calculation seems of different degree for the set III and IV.
Experimental results have been obtained also with the targets of 50Ti and 54Pe. Analysis ofthese data is going on.

References

1)

T. Tamura and K. S. Low: Private communication.

2)

H. J. Korner, G.C.Morrison, L. R. Greenwood, and R. H. Siemssen: Phys. Rev., C7, 107 (1973).

30

4-7.

long-Range a-Particle Decays and level Structure of · 216Ra

T. Nomura, K. Hiruta, M. Yoshie, H. Ikezoe,
T. Fukuda, and O. Hashimoto*We have studied the level structure of 216Ra by means of in-beam spectroscopy forlong-range a-particle decays and 'Y-rays following the 2osPbe 2C, 4n) and 207Pbe 2C, 3n) reactions
and established the level sequence up to 11- (possibly 14+), including a 7 nsec isomer with spin
8+.

Short-lived a-particle decays were observed from 4+, 6+, 8+, and 10+ states; their reduced

widths were estimated from the branching ratios of a- to 'Y-transitions.
- r - - - ( 14 +)( 329l.3 )
:

•

344.3

-T - - -( 12 + ) (2947.0 )

I

I
I

612.9
11 - 2334.1
309. 1
10 + 2025.0
314 . 6203.5

8 + 1710.4
6 + 1506.9

11.593 (0.12 )343 . 5

11.270 (0.88 )11 . 061 ( 0 . 58 )4 + 1163.4
475 . 5

10 .723 (0.23 k
9.765 (0.98 )9 . 559 ( 100 )Qa ( r a j rt otal )MeV fir)F

2+ 687.9

0+

0

216Ra

Fig. 1. A decay scheme of 216 Ra established in thiswork. The level sequence of 212Rn is takenfrom Ref. 1.
* Institute for Nuclear Study , Tokyo University

31

A decay scheme of 216Ra constructed in this work is shown in Fig. 1.

Decay propertiesof long-range a-particle transitions observed are summarized in Table 1.

Table 1. Transition properties of long-range a-particle decays from 216Ra.

Qa
Ji~Jf
Ea
(MeV) (MeV)

t1 /2 (1i)(ns)

ra/rtotal t 1/2, a(exp) t I12, a (cal)a)
(ns)
(ns)
(%)

HF

HF(L)b) Reduced
HF

182± 10 c )100

182± 10

182

[ 1]

11

[ 1]

9.765 (8+~4+) 7.0±0.7
0.10 d )10.491 10.723 4+~0+0.98

714±91

63.0

11

4.8

2.3

0.23

48

0.929

50

4.2

12

9.349 9.559

O+~O+

9.551

6+~0+

0.51 d)

0.58

88

0.275

314

19

17

11.028 11.270 8+~0+

7.0±0.7
0.79 d )0.88

795±84

0.120

6630

135

49

0.12

658

0.042

15700 1270

1210.823 11.061

11.345 11.593 10+~O+
a)
b)
c)
d)

Calculated from the barrier penetrability for S-wave a-particles and normalized on the groundstatea-decay.
Hindrance factors due to the centrifugal barrier are calculated from the formula given in Ref. 2.
Taken from Ref. 3.
Calculated values.

References

1)

K. H. Maier, J. R. Leigh, F. Pilhlhofer, and R. M. Diamond: J. de Physique, C6, 221(1971).

2)

J. O. Rasmussen: Nuc!. Phys., 44, 93 (1963); J. O. Rasmussen: "Alpha-, Beta- andGamma-ray Spectroscopy", Ed. K. Siegbahn, North-Holland, Amsterdam, p. 701 (1968).

3)

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

32

4-8.

Angular Distributions of long-Range a-Particles Emitted fromHigh Spin States in 216Ra and Statistical Tensors

T. Fukuda, T. Nomura, W. Kutschera, and K. Hiruta

In a preceeding paperI), we have shown that high-spin states in 216Ra decay with a-particle
transition in competition with ),-ray emission.

Angular distributions of these a-particles must

be governed by the high rank of statistical tensors like· P6 and Ps, and therefore are expected
to give more complete information on the nuclear alignment produced by nuclear reactions,which can hardly be obtained by ),-ray angular distribution measurements.
Angular distributions of a-particles from J+ (J = 4, 6, 8: 216Ra) -+ 0+ e12 Rn) transitions
were measured from 6° to 90° in the 207PbC 2C, 3n) reaction at Ec12 = 72 MeV. Figure I shows
the angular distributions normalized to the yield of the ground-to-ground decay whose angular
distribution must be isotropic.

The angular distribution of the 8+ -+ 0+ a-particle transition

can be written in the following way:W ( e)ex L

P k ( J = 8) b k (L = 8) F k (0 L L) P k ( cos e)

k

2.5

I

I

_2 .0

o§

1/

>-

L

0

-e
2 1.5

8+-0+

tI
I

I

-0

a;
>-

6+- 0+

Cl>

>

I/

"'(:;

a; 1.0

I

0::

0.5

II

I I

I

4+-0+

/ :

I

I
I
j
I
I
I
I
0~-L~2~0~~~40~~~6~0--~~80~~e (deg.)Fig. 1. Angular distributions of a-particles
from the 4+, 6+, and 8+ states in
216Ra.

33

where the notation is conventional (b k is the particle parameter for a-transition with angularmomentum L = 8).

It should be noted that the angular distributions for 4+ --* 0+ and 6+ --* 0+

can be expressed using the same statistical tensors because they are populated by the E2-y-transitions following the -y-decay of the 8+ state!)
The statistical tensors for the 8+ state yielded from a preliminary analysis ofwee: 8+ --* 0+) is given in Table 1. A more accurate analysis is now in progress.

Table 1. Statistical tensors for the 8+ state.

-0.762 ± 0.025

0.562 ± 0.035-0.234 ± 0.045

Ps

PIO

0.065 ± 0.054- 0.012 ± 0.053

Reference

1)

T. Nomura, K. Hiruta, M. Yoshie, H. Ikezoe , T. Fukuda, and O. Hasimoto
Cyclotron Progress Report,-8, 30 (1974)

IPCR

34

4-9.

3

3

The (He,

3He), (He,

3

/

3

.

He), and ( He, Q:') Reactions on

13

C

T. Fujisawa, H. Kamitsubo, T. Wada, M. Koike
Y. Tagishi, '* and T. Kanai

Differential cross sections of eHe, 3He), eHe, 3He'), and eHe, a) reactions on 13C have
10

4

•

o

..

29.2 MeV
34.7 MeV•

39.6 MeV

o

°
£>

0
00

L

o

-+-'

a

(f)

-......

...a

E

..-.

~ 10 2

°0

~

....

"b

..

-0

10

1

..
o
o 0

10

o

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

.......

..

........

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

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

.....

e c.rn .
Fig. l. a)

Elastic scattering. The open mark indicates the cross section obtained fromsubtracting the estimated yield of the elastic scattering on 12 C from the overlaped
yields of the elastic scatterings on 12C and 13C.

* Tokyo Univ. of Edu ca tion

35
10 '

13C(3He ,3He') 13C

I·.

state

3.09 MeV

...

10°

·u,!

,.
!

J~

....

.
.. .
10-

~101

,,

+

13

f~t

!

'ii' ..

!,+tt+++,'+','.........

...0

+

E

,~t

t t

,··-tt ! f +'tnt,~...

........

.......
e •••••••

tf..................

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

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

..... .

m,tt

. ....... ..

....

... -.

.

10-1

1-

•!

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

...

.g 10°t UH t...

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

"-..

tt

3.68 MeV state + 3.85 MeV statea.- ••••••••

c:::
"b
~

..

C ( 3 He, 3 He') 1 3 C...... .. .

T

IO~~O----~3~0~O----~~----~-----1~200

e c.m.

e c.rn.
b)

The 3.09 MeV 0/2+) state of 13 c.

c)

Sum of the 3.68 MeV 0/2-) and 3.85 MeV(5/2+) states of 13C.
10 '

13C( 3He, 3He') 13 C

7.50 MeV state + 7. 55 MeV state + 7. 68 MeV state......
. . ... ..1 ...

13C (3He, 3He') '3 C

... -

..

6 .73 MeV sta te

I ••••••••••... ...... .

".... ......

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

L

+-'
if)

'-

-El0-

.......

1~+-++ +4 H ·

t t

"-..

b

"b

t

t .

~ t

-...-. ....

t

....

~

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

...........

..

.. . . . ..

.

; T1
,

10-~L:-o-----=3~0-=-o-----=6~
O-=-o------::9:-::0-=o-------;1~2:::;-O;;--olvO~O----~
3=
0~O--~6~0~
O ----~9~0-=O ----~
12:-::0-=O-----::1~5:::;0~O--~
18 0°

e c. m.
d)

The 6.87 MeV (5/2+) state of 13C.

Sc.m.

e)

Sum of the 7.50 MeV, 7.55 MeV and 7.68 MeV(3/2+) states of 13 C.
Fig. 1. Angular distributions of the differential cross sections of the 13CeHe, 3He) 13 C
and 13 Ce He, 3 He / )13 C reactions.

1

1

b

b

-0

"'-.

r
'-.l

U>

1O- ~o

10-2

10-1

10 '

I

30 0

..

t

~...

..+

'+

'!

ac.m.

1
90 0

'h

~

P

~

tf

t

t

! T

fH

,

r~ff# ij f t

W\

+,

jlffi

1
120 0

II

t

t

tt

! t ! !!\

t

+t

I

' '" ,'.

•'jground state

The ground (0+) state of 12C.

1
60 0

...

U

•, •• ' ,i,

.£.

--.

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

£

•

....

34.7 MeV• 39.6 MeV.&• 29.2 MeV

13C( 3He,a )12 C

••••

u"

Fig. 2. a)

-

•

·

H
"I "
•

"...

\ t

,

T

,

~ at f

.

Oo~
~b 1

10 0l

10

~

.g

'-..

I
!

,

T

10- 6 0

10- 2

10-1

3100

.....

...

... ......

..

....

I· •

Fig. 2. b)

IIJ......

••
.....

••

...

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

ac.m.

900

.......

£

1200

f.

1500

t++/

t... ...
!'f 'T"tt'f •4 ~, •••....... ·f.
...

• n·tttt
tt
!

l£

. ..

~t

tt

The 4.43 MeV (2+) state of 12C.

600

A. ..

..

.AJt. ..

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

..

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

4.43 MeV state

13C( 3He ,ex )12 C

1 '... ..

~ 100

~

E

.n

.........

U>

.b

1

10 0

10

180 0

W
0\

-..:

.g

~

t,

30 0

Fig. 2. c)

10 0 "

-4

10- 3

10- 2

~ 10-\

E

Ll........

(f)

-+-'

A•

t

i,

f

I lit!!

!

B c. rn .

90 0

fI!!~

II
j

+

+

120 0

+tf~

150 0

t

!!j!~1The 7.66 MeV (0+) state of 12C.

60 0

+

f/H+++•lA,A+

++~ T

,'H H

Ht

+

!+ !

!t+!

T

7.66 MeV state

13C(3He,cx)'2C

IIIl I I+

A.

rtf.t.

IJ..

11!!+'!o 1_,

lij

10-\

10°

(f)

~
......

t:>
"1:J

10- 0

0

10- 2

~ 10-\~

E

Ll........

10-\

10-\

10°

;+,+

t

t

•T'

;

. ft

f i!

B c.rn .

1

900

tt

/1

120 0

150 0

t t t !'t+
i t ' f ;tt+!+r'f+f4+,.. ...

The 9.64 MeV (3-) state of 12C.

1

600

f

t

't

f

++

*++++

!+

Htt!,+, ,+ ,ff !tttfHt f·Hhtf fA.··U•

!tH

+I f

3'0 0

f

I, • !'i • + ' +i +j • •Fig. 2. d)

f Itl

+
!

9.64 MeV state

13C( 3He ,ex) 12C

1800

-...)

w

38

13 C( 3He , 0') 12 C

12. 7 MeV state

... .

.

.

•• J' •••..

.. ....

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

...........

.....

• .&

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

..

......

.....

.

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

10-20~o.----,3~0~o.---~
60noo----~9~0~o----~1~2~
0~o----~~---180 °e c. rn .
e)

The 12.7 MeV (1+) state of 12C

•,

13

12
C{3H e, ex ) C

15 .1 MeV
+ •
+••••

13C{3He,cx)12C

16.1 MeV state

..

state
•

0

.-... -...
O D

000

o

..
t..

....

...

....

..
...

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

•......

DO

••

o

0
0

00°0

o

..

o

o
0 00

. . . . . . . . . . . . . . . . ..
00._

.....

0000000 0 000°0°

. 0

00

0

1 0-~~o~--~3~!0~O~--~
60~O~--~9~!0~O-----1~2-0-o
I

Scm .

The 15.1 MeVO+)stateof I2 C. The open
mark shows the cross section obtained fromsubtracting the estimated yield of the ground stateof 11 C from the overlaped yields of the 15.1 MeV
state of 12C and the ground state of 11 C.
f)

Sc.rn.

g) The 16.1 MeV(2+)stateof I2 C. The open
mark indicates the cross section obtained fromsubtracting the estimated yield of the 2.0 MeV
state of II C from the overlaped yields of the
16.1 MeV state of 12C and the 2.0 MeV stateof 11 C.

Fig. 2. Angular distributions of the differential cross sections of the

39

been measured at incident energies of 29.2, 34.7, and 39.6 MeV in order to study the mechanismof these reactions.

The angular distributions of the differential cross sections are shown in

Figs. I and 2. The experimental procedure of the study was reported previously. 1)

Reference

1)

T. Fujisawa, H. Kamitsubo, T. Wada, M. Koike, Y. Tagishi, and T. Kanai: IPCR Cyclotron
Progr. Rep., 7, 46 (1973).

40

A

4-10.

Study of Resonance States Induced by
28

16

3

O( He, d)3

Si ( He, d)

29

17

F and
.

P Reactions

K. Koyama, N. Nakanishi, H. Yokomizo,
S. Yamada, and H. Ohnuma
Recently the study of stripping reactions leading to unbound states have been improved
very much, particularly on the theoretical treatment in the framework of the DWBA.

Aninteresting object of this study is the possibility of comparing the unbound form factors withthose extracted from the resonance reactions, which may be a cross check to the mechanismsof these two different types of reactions.
Differential cross sections were measured on the reaction 28SiCHe, d) 29 P at an incident
energy of 29.3 MeV and the reaction

160CHe, d)17F at 41.5 MeV.

The 28Si target wasa self-supporting foil of natural silicon with thickness of 1.98 mg/cm 2 which was prepared by
The 16 0 target was of gas type.

vacuum evaporation.

Two gas chambers were prepared; one
had 5 J,Lm nickel foil windows, the other had 3 J.Lill Havar foil and 0.5 mg/cm 2 Mylar foil windows,
and gas pressures were 365 Torr. and 260 Torr. respectively.
15

1500
lo)

~o

2000

28

~ 1000S j( J He,dl 29 p

E3He = 29.3 MeV

10BLob. = 15°

'"c
=>

o
U

1500

5
~

~

><
Lu

CI>
C
C
C
L

U

...... 1000
-+-'
'"
C

1200 I'"

ChanneloUnumber

1400

0

,I

( b)

I
160!

500

l7

3He,dl F"

E3He=41.5MeV
BLab.

200

5

= 17.5°

400

800

600
Channel

1000

1200

1400

numberFig. 1. Typical spectra of deuteron from the reactions 28SiCHe, d) 29 P and 160CHe, d)17F.

41

The optical potential parameters for 3He and deuteron.

Table 1.

The notations are the same as used in Ref. 1.

wD

rD

aD

2.1

1.0

0.86

0.81

20

1.34

0.68

1.15

0.81

20

1.34

0.68

Vso

rso

a so

rc

6.4

1.28

0.41

1.25

4.5

1.3

0.6

1.3

1. 78MeV

2+

v

r

a

W

rw

aw

3He + 28Si
3He + 16 0

151

1.11

0.73

24.8

1.60

0.756

185

1.18

0.56

8.17

1.67

1.46

d + 29p80

1.15

d + 17F

79.3

3He + 28Si
3He + 16 0
d + 29p

1.4

d + 17F

1.4
10 2

1 0 °,---------------------------~..

160(3 He ,3He)160

6.05 MeV 0+( 6.13 MeV T

of.
6.92 MeV( 7.12 MeV...
\ 0- 20~o--~~~3~0~o~--~~6~0~o~--~~90~O
Sc.rn.

Fig. 2. The angular distributions of 3 He

Sc.rn.

Fig. 3. The angular distributions of 3He

elastically scattered from 28 Si

inelastically scattered from 28 Si

and 16 0. The curves are obtained

and 16 0. The curves are obtainedby an optical model calculation.

by a DWBA calculation using
macroscopic form factors.

42

10 '

10 '

28 S i (3He , d) 29p

E3He = 29.3 MeV

10°

10°
3.\0 MeV 5/2t-•
0.0 MeV 1/2+

+

•+

10°

10 '
3.43 MeVt
10'

t++ 4.08 MeV'+ (3 /2 - )1.36 Wev 3/2+
~

c.:

+ t

~
10°
.0

f +~

~1O-1
.D

E

E

I

t
1. 96 MeV 512+
10°

t

+,

tt

ttl t

10 '
3/2-

+

f
ttt t

t

10-1

t

t

2.4 MeV 3/2 +

t

10°

••

5.75 MeV

~Mev
3/2+

+

t tt +t t

\

jj

10-2
6.33 MeV (512+)

ttf

j

liZ-

+\

tj

+~

10- 1

t
10-3
00

t

10-2
30°

ec.m.

90°

0°

90-

30°
B c.m.

Fig. 4. The differential cross sections of the reaction 28 SiC He, d)2 9 p. The curves
are obtained by a DWBA calculation. For the resonance states (higher
energy states than 2.745 MeV), we used loosely bound form factors.

43

The energy spectra of deuteron, helium-3 and a-particles were measured by using an ORTEC
Typical energy spectra of deuterons are shown in Fig. 1. Figure
2 gives the angular distributions of 3He elastically scattered from 28Si and 16 0, and the curves

particle identification system.

are obtained by an optical model calculation using the code "SEARCH", 1) the parameters being
Figure 3 shows the angular distributions of 3He inelastically scattered fromgiven in Table 1.
28Si and 16 0.

10 2 c - - - -- - - -- - -- - - - - ,

.\

\

\

\.

\,

.,.

10°

~

'-D

'. g.,,\~+
..

E

10

.. ,

1

Fig. 5. The differential crosssections of the reaction 16 0•••••\eHe, d)17P. The curves arer2

5.7MeV..~similar to those of Fig. 4 .
The resonance states arehigher energy states thanI
10 - 1Os,-o--'---------'----::-'-:30=0------'----.J.j -----"-Or-I ------c- oo- - l . - - . J
T 6
L-

0.601 MeV.

Bc.mFigures 4 and 5 show the differential cross sections of the reactions 28SieHe, d) 29 P and
16

0 eHe, d) 17F, respectively.

The solid curves of Figs. 3, 4 and 5 give preliminary predictions

obtained by a DWBA calculation using the code DWUCK with a computer TOSBAC-3400.
For the resonance states, we used loosely bound form factors.

The optical potentials of

deuteron were deduced from C. M. Perey and F. G. Perey's formula,2) and they are given in
Table 1.

Calculations using resonance form factors are now in progress.

References
1)

T. Wada: IPCR Cyclotron Progr. Rep., ~, 87 (1968).

2)

C. M. Perey and F. G. Perey: Nuclear Data Table, .!1, No.4, 293 (1974).

44

4-11.

58,60,62, 64· (3d) 59, 61, 63,65
N I He,Cu.

Reactions andthe Correlation between Unbound States andResonance States

R. Sakaguchi, M. Nakamura, S. Takeuchi, *N. Nakanishi, and S. Takeda**

Particular interest in stripping reactions to unbound states was recently initiated by papers 1)-3)
reporting anomalies in eRe, d) and (d, n) reactions.

In spite of remarkable progress thereafter4

in the theoretical treatment )-6) on one-nucleon transfer reactions to unbound states, it has notbeen established to use this reaction as a spectroscopical tool, because of the uncertainty intreating the continuum background, which is observed at the enhanced unbound state peak in theenergy spectrum of emitted particles.

The final state selectivity due to the direct reaction

mechanism is, however, effective in these reactions if we choose the incident beam energy highenough, and this selectivity gives us useful information about the structure of resonance statesfound in (p, po) and (p, p') reactions on the same target.
3Re-beams of various energies between 22 and 47 Me V from the Cyclotron were bombardedon the Ni-isotope targets and emitted deuterons were measured with a 6 E - E counter telescope
and a Goulding type particle identifier.

Figure 1 shows typical deuteron spectra in eRe, d).....c
IJ')

IJ').....c

:;J

:;J

o

o

<..)

<..)

30
Excitationa)

Excitat;on energy

energy6°NieHe, d)61 Cu, eLab = 25° , E3 He =35.5 MeVb)

62NieHe, d) 63 Cu, eLab = 30°, E 3He =35.5 MeV

Fig. 1. Typical deuteron energy spectra obtained in* Department of Physics, Kyoto University** National Laboratory for High Energy Physics

eHe, d) reactions.

45

58 Ni ( ?' , d ) 59CU

/70'" / \!
\

Er =29.317MeV\

Experi ment al\

10

58Ni (T, d) 59Cu
I

DWUCK

.

/

\

10

\

( Preliminary)
-

10-

Q 1

,""

Q

3.558 MeV
3.586MeV(lp = 2)
[ 3.629 MeV

! !
Q
Q !.

I

\

0

0

DW UC K00 MeV 3/2-\\

I

Experimental.

0

,

\vI\
':

I

Er = 29 .317MeV 40.0 MeV-,(Pre lim inary)
, !

~\

I

40.0 MeV

!

I
Q 0

\

\

\

0 \

\

I

o

J

_,1/\

QI,/V\
Q Q Q

o

\

101-

o

f

\

\
Q\

\
d\

Q

o
Q

:g

\

"-

I
~/

t J J

E

1Or-

10

-

3.90 I MeV (fp= 1)
I.AS af 59Ni (g.5.)

-

t

:::

Q!

!

Q

I.

o

o

I

o

ott
-

o

II-

::

4.267 MeV
Q Q
*4.313MeV (Pp=3)[ *4. 362MeVtj1p = I)

* l. A. S ot 59 Ni

I

I

I

I

10°

e m.
C.

Fig. 2. Measured angular distributions in the 58 NiC He, d)65 eu
reaction. Optical potential parameters used to calculate
the DWUCK are V R = 89.0 MeV, rR = 1.15 fm, a R = 0.81 fm,

Ws = 19.6 MeV, rI = 1.34 fm , aI = 0.68 fm, for deuterons andV R = 179.5 MeV, rR = 1.11 fm, a R = 0.77 fm, WI = 20.6 MeV,
rI = 1.615 fm, aI = 0.74 fm for 3He.

\

\

c

'\

\,

\

,,",\\A. \Sc.rn.

\

\ \

-.\

~~

\

50°

0.1

0°

0.1

0.1 .: 1.0~.......

25 1

t

V\

2.06 '\+\~......

10°

20°

40 °

~

\ .'+
30°

,\.~

Sc.rn

..\

\

+,

\\

\-,
.\

0.1

,10

50°

are used only to connect the measured values.

0 .1

0.1

\ 1

\L"'~ ""

' .'\
'~

\

•

\

\ .

•

,I \\

4.06

3.58

•

\./~\ ~~\

1\

1

Ir

Fig. 3. 62 Nie He, d)63 Cu angular distributions. Solid lines

0°

0.1

1.41

\

\

~ '1°96\\ ~

i.l\

\(\
. \

V\

\~

\f\

067 \

9'S

1

10 ,

62Ni(3He,d)63CU
E3He=35 .5MeV
,1 0
10,

'"

)-

'VOl

2

1.0

eLm

e"m

'"
20·
30·

ro= 1.31

ro= 1.51

2

.l

40·

'~

1.1 15 MeV

\(

/ }A\

1.620 MeV

. (f ,t)~+-~d'str,bulions)He VR= + 179.5 ro= 1.2 I WI =+20.04
D VR=+ 95.4 ro =1.075 Wrs =+ 11.81
"
10·
20·
30·
40·
10·

DWUCK Calcu .

Exp.

f

O.77M"

GND

if\

\v \

V·

Angular

Er = 35.5 MeV

Ni I r . d )65 Cu\

4

11.81 MeV, rI = 1.31 fm for deuterons.

V R = 95.4 MeV, r R = 1.0075 fm, Ws =20.04 MeV, r I = 1.51 fm for 3 He and

VR = 179.5 MeV,rR = 1.21 fm, Wv =DWUCK. Used optical parameters are

Solid lines show the calculations with

Fig. 4. 64Nie He, d)65 Cu angular distributions.

0.011
O·

0.1

1.0

E

1.0

f,

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

+::-

0\

47

reactions.

There we notice a remarkable gross structure of the background bump in the proton

unbound energy region, over which enhanced peaks of unbound analog states are observed.
Calculations using the Vincent-Fortune type DWBA analysis coded by Igarashi and Kawai,7)
where the radial integral to r = 00 is replaced with the integral in the complex r-plane by useof the analytical continuation, enabled to explain only the 1/30 of the proton width rp of theenhanced unbound peak. Angular distributions of 58,62,64Ni(3He,d)59,63,65Cu are shown in
Figs. 2,3, and 4, respectively. For well-separated bound states, measured angular distributions werefitted using the code of DWUCK (see Figs. 2 and 4). In order to investigate the origin of thebump structure, energy spectra of deuterons were measured at various incident 3He-beamenergies, by ' changing the target mass.
1)

Remarkable features of the bump are as follows:

The yield of the background bump is strongly dependent on the incident beam energy.

Bump cross sections grow up as the beam energy increases.
2)

The position of the maximum in the bump energy spectrum relative to the proton

separation energy does not change remarkably with increase of the target mass number.
Analysis on the bump structure using various form factors and models is in progress.

References

1)

U. Strohbusch, H. J. Korner, G. C. Morrison, and J. P. Schiffer: Phys. Rev. Lett.,
28, 47 (1972).

2)

R. L. McGrath, N. Cue, W. R. Hering, L. L. Lee, Jr., B. L. Liebler, and Z. Vager:
ibid., 25, 682 (1970).

3)

S. A. A. Zaiai, C. L. Hollas, J. L. Horton, P. J. Riley, J. L. C. Ford, Jr., and C. M. Jones:
ibid., p. 1503 (1970).

4)

B. J. Cole, R. Huby, and J. R. Mines: ibid., 26, 204 (1971).

5)

C. M. Vincent and H. T. Fortune: Phys. Rev., C4, 236 (1971).

6)

C. M. Vincent and H. T. Fortune: ibid., C8, 1084 (1973).

7)

Private communications and M. Kawai and M. Igarashi: Research Center for Nuclear
Physics Report RCNP-P-l, p.40 (1974).

48

4-12.

Analyses of Cr eHe, d) Mn Reactions at 29.29 MeV

N. Nakanishi, S. Takeda,* H. Ohnuma, S. Yamada,
H. Sakaguchi, M. Nakamura, S. Takeuchi, * * and K. Koyama
Differential cross sections were measured on the 50,52, 54Cr eHe, d)5 1, 53,55Mn reactions at
a 3He-energy of 29.29 MeV 1) and analyses of them have been carried out.
As optical model parameters were employed a deep potential family (V ~ 180 MeV) for3He particles and a Perey-Perey's set for deuteron particles.
For proton-bound states, conventional DWBA analyses were carried out to obtaintheoretical angular distributions and spectroscopic factors.

As an example, the calculated resultson sOCreHe, d)SlMn reactions are shown in Fig. 1 and Table 1.

In Fig. 1, Rp = 2 and Rp =were assigned to the 2.99 MeV level transfer in Refs. 2 and 3 respectively.
be seen that.e p = 3 gives better fits.

However, it can

Angular momentum Rp = 3 may be assigned to the

4.93 MeV level.
Table 1. Transition strength of the sOCreHe, d)S 1 Mn (bound states).
r-E_h_-_-_2_9_.-..2: MeV (Present) ,--....__E..:.:h~=..A.. -12_M-e-V_2)----.
J1T
C2 (2J+l)S Rp
J1T
C2 (2J+l)S'

.e~
0.24

3

7/2-

2.26

3

7/5-

ip

2.33

3

7/2-

2.62

3/2-

0.75

1.83

0.56

0.63

1.95

0.23

0.21

3/2-

1/2-

0.33

2.13

0.39

0.35

3/2-

1/2-

0.54

2.84

0.25

0.20

3/2-

1/2-

0.39

{O.IS Oct)

3/2-

1/2-

0.04

2.99

(3)

3.28

3

(5/2r

4.44

3

7/2- lAS {

4.71

(0.2)

0.04

4.93

3

0.08

5.10

74
r·0
5.128

lAS

(3/2)+

0.90

2

1.89

3

0.84

0.85

3 7/2- lAS

0.55

(2)

0.02

(s=0.32)

0.77* National Laboratory for High Energy Physics.
** Kyoto University.

:

0.06 (2d)0.04
1/2- lAS{ 3/2- lAS

(0.23
0.37

3

5/2-

2.69

49
50Cr( 3He,d )51Mn

Eh =29. 29 MeV

2.99 MeV(i=3)

0.24 MeV

.

i= 3

~..

71Z-

1O-1r--------------~-

_..
\.,.A
V
\

4 .44 MeV lAS

1. 83MeV

1 =3
712 -

i= 1

·~
_3_/2_-

i,O,f------.
_·\_.=t--__________

1.95 MeV

Q= l

10'

---....~

•• •

• • •

V\

2. 13 MeV\.;~\ I~ I"\

4.93 MeV\\

1O°l---- -\c-----------~~---\/.,=-=--;;..\

2.84MeV

•

••

Q= 1

~
40

50

".

.
~.. .

10°f--- - --

50

-

1= 3

\
\

+'

~t=l3
~=

5.0 745.10 { 5.1 28 lA S-----ik------ -

i=1

30

Fig. 1. Angular distributions for transitions to bound states of sOCrCHe, d)Sl Mn
reaction at an incident energy of 29.29 MeV.

The 5.10 level is composed of lAS 5.074 and 5.128 MeV levels. It was unable to observe
these levels separately.
For proton-unbound states we have carried out some trial calculations to .reproduce theseangular distributions.

Some of them are shown in Figs. 2 and 3 for the Ex = 12.35 MeV

9/2+ state of sSMn (the isobaric analogue state of sSCr 2.09 MeV 9/2+ state).

Figure 2 shows

form factors for the paren.t nucleus, a loosely bound state and a single particle resonant state 4 )

50

55Mn
(55Cr

10-1 1------;~~------/\~:...

12 .35 MeV
2.09 MeV 9/2+

lAS)

10-21~'' - - - --;_...~.. _ ; _ _ - -x•

(Si ngle particle re sonance)

10- ' L- -- - - - - - - ~-~~--(5'Cr+n) •10-51-_x_ _ _ _ _ __ _ __ _ _· ---'----'(-=B-"E=-10 ~ __

~

10

20

30

r (1m)

Fig. 2. Form factors for a 12.35 MeV 9/2+ state of sSMn. Crosssign, small dots and large ones show form factors of aneutron of a parent nucleus, of a proton loosely boundand of a proton on the assumption of a single particle
resonance , respectively.

f h = 29. 29 MeV
fx=12.35 MeV- - S Ing le port Icle resona nce
Parentnucleus

Loosely bound parton

""

"

~.~,
. ~,
"

Sc.rn (deg.l

Fig. 3. A typical angular distribution for a sSMn
12 .35 MeV 9/2+ proton-unbound state.
Calculated curves are normalized arbitrarily
to experimental points.

51

by cross signs, smaller and larger dots, respectively.
distributions and the experimental values.

Figure 3 shows the calculated angular

In this case, proton form factors were employed as

seen in Fig. 2. Overlap integrals were performed using a code "INS-DWBA2" ,5) which adopts
the Vincent-Fortune method 6 ) in case of integration of a scattering state.

References
1)

N. Nakanishi, S. Takeda, H. Ohnuma, S. Yamada, H. Sakaguchi, M. Nakamura, S. Takeuchi,
and K. Koyama: IPCR Cyclotron Progr. Rep.,1., 42 (1973).

2)

J. Rapaport, T. Belote, and W. E. Dorenbuch: Nucl. Phys., AIOO, 280 (1967).

3)

B. CUjec and I. M. Szoghy: Phys. Rev., 179, 1060 (1969).

4)

W. R. Coker and G. W. Hoffmann: Z. Physik, 263, 179 (1973).

5)

The code "INS-DWBA2" was newly improved by M. Igarashi.

6)

C. M. Vincent and H. T. Fortune: Phys. Rev., C2, 782 (1970).

52

4-13.

Full Finite-Range DWBA Calculations for Heavy-Ion Induced
Two-Nucleon Transfer Reactions

T. Takemasa

Recently heavy-ion induced two-nucleon transfer reactions have been of much interest.
Several authors l ) - 3) have attempted to calculate differential cross sections of such reactions.
However, all the calculations except the work of Bayman4) are based on a no-recoil approximation.
Apparently it may be misleading to ignore the recoil effects for these reactions and thespectroscopic information can be only achieved through an exact finite-range calculation including
a microscopic form factor.
We have recently completed a finite-range full-recoil DWBA code which also includes the
microscopic form factor. 5) The methodology given there used the multipole expansion of thetwo nucleon overlap in terms of the relative angular momentum .e of a transferred nucleon pair.
Here we report a finite-range full-recoil DWBA calculation for the reaction 12C (180, 16 0)
The optical potential parameters are the same as those used in Ref.3; Vo = 200 Me V,
isWvol = 10 MeV, R = 1.25 (A~/3 + A~/3) fm, and ao = 0.5 fm. The overlap < 14 C 12 C>
14Cg.S..

1

assumed to be a pure (OPl/2)2 configuration and < 18 0

1

16 0> to be the admixed configuration

given by Federman and Talmi.6)
We first investigated the convergence of the £ series. The differential cross sections were
calculated as a function of the quantum number
is fairly rapid.

e (Fig. 1). As can be seen, the convergence

We found that taking account up toaccuracy of better thane= 3 term is enough to ensure an- 2 % in the differential cross section.

This fact points out that itis quite practical to use this method for the systematic analysis of experimental data.
In Fig. 2, the finite-range full-recoil DWBA calculations are compared with the finite-range
no-recoil ones 3) and also with the experimental data.7) The normalization factors N = aCe )exp.

la(e )theor. for the full-recoil (no-recoil) curves are 250 (500), III (72), and 140 (138) for
Elab = 16, 20, and 24 MeV, respectively. The full-recoil curve at Elab = 16 MeV is greatly
different from the no- recoil curve.

However, the recoil effects do not affect the shape of theangular distributions at Elab = 20 and 24 MeV.

53

10r-------------------------------~

No recoi I
Full reco i l[= 16 MeV

0.1

£ =24 MeV'........

en........

E= 20MeV

..0

E
~

-a

"'b

-0

101

0.1

[=24MeV

1=3

o

150

30
8 c.m• (deg.)

Fig. 2. Comparison of the finite-range

Fig. 1. Plot of the differential crosssections for the 'f = 0 - 3 for the

full-recoil and finite-range

reaction 12CeSO, 160)14C

no-recoil 3 ) DWBA calculations

E1ab = 24 MeV.

g.s.

at

with the experimental differential
cross section. 7 )

180

54

References

1)

A. J. Baltz and S. Kahana: Phys. Rev. Lett. , 29 , 1267 (1972).

2)

A. Roberts: Nucl. Phys., A196 , 465 (1972).

3)

R. A. Broglia et al.: Kernforschungsan1age Jii1ich Internal Report, 1973, (unpublished) .

4)

B. F. Bayman: Phys. Rev. Lett. , 32; 71 (1974).

5)

T. Takemasa: Phys. Lett., (1975), (in press).

6)

P. Federman and I. Ta1mi: Phys. Lett., 12, 590 (1965).

7)

P. H. Barker et al.: Proc. Int. Conf. on Nuclear Reactions Induced by Heavy Ions,
Heidelberg , 1969 , North-Holland, Amsterdam , p. 152 (1970).

55

4-14.

Two-Nuc leon Transfer Reactions between Heavy Ions

T. Takemasa

A method 1) was developed for exact evaluation of the DWBA transition amplitude in
two-nucleon transfer reactions between heavy ions.

It is based on an expansion of a two-nucleon

overlap fuction ('l' (b) I V I 'l' ( b+ 2 ) >in multipole series of the relative angular momentum f of atransferred nucleon pair. The perturbation interaction acting between the core and eachtransferred nucleon is taken into account, and it is therefore possible to extract the proper
spectroscopic information by comparing the calculated results with the experimental data.

A

Fig. 1. Coordinate system for the reaction A(a, b)B where
B = A + 2n, a = b + 2n.
Figure 1 shows a relevant vector diagram for the two-nucleon transfer A(a, b) B (B = A +2n, a = b + 2n). The form factor < 'l'B'l' I {V (r/l ) + V (r/2)} I 'l'b

A

can be factorized as follows :< 'l'B 'l'b I { V (r/1 ) + V (r~)} I 'l'A 'l'a >= < 'l'B I 'l'A> < 'l'b l{ V (r /1) + V (r~)} I 'l'a > .

'l' > (post representation)a(1 )we consider a multipole expansion of the radial part of the overlap< 'l'bl { V ( r/1) + V (r'2)} I 'l'a > :{ V ( r 11 ) + V (r 'z)} cD ~', (1)1,
L'

r~)
L'

=""'~ g'" '" (r, R z) [Y ff (f. ) X YL' (R 2) ] M' ,P' L '

pI L '(2)

56

and a similar multipole expansion is carried out for the overlap
these expansions into Eqn. (1) and integrating overInsertingr, we can obtain the following expression

for the form factor :(3)

where SAB(Sab) is the two-nucleon parentage coefficient for the target (projectile) nucleus,"""-",

C(LL'SQLL') is the angular momentum coupling coefficient and S is the total spin angularmomentum of the two transferred nucleons.

The radial part of the form factor F ,,-L~:' (R l , R 2 )QjLL'

can be expressed by(4 )where the function f~I: is the radial part of the multipole expansion of the overlap < WB' W > .
A
The angular momentum coupling diagram is exhibited in Fig. 2. It is to be observed thatthe quantum number .£ is the total transferred angular momentum.

The resultant formalism

which can exactly treat the DWBA amplitude for the two-nucleon transfer between heavy ionshas been coded by suitably extending the existing single-particle DWBA code DWBA4.3)
The coding has been checked by comparing results with those given by Bayman. 4 )Fig. 2. Angular momentum coupling diagram ina transfer reaction. The total angularmomentum of a transferred pair in the
projectile nucleus is l' = L' + S and it istransferred to J = L + S in the residual
nucleus. The total transferred angularmomentum is.£ which is the sum of thecenter of mass angular momentums in
the projectile and residual nuclei.

57

References
1)

T. Takemasa: Phys. Lett., (in press).

2)

C. W. Wong and D. M. Clement: Nucl. Phys., A183, 210 (1972).

3)

H. Yoshida: DWBA code DWBA4 (unpublished).

4)

B. F. Bayman: Phys. Rev. Lett.,ll, 71 (1974).

58

4-15.

One-and Two-step Processes in the Heavy-Ion Induced
Two-nucleon Transfer Reaction

T. Kammuri

Two-nucleon transfer reactions induced by light particles have been analyzed by means of
the first-order DWBA method, in which the nucleon pair is assumed to be transferred through asingle interaction with the core.

In the collision between two nuclei in the independent-particle

model limit, two nucleons can be transferred one by one, with one interaction in each transfer.
Usually two nucleons have some degrees of correlation. At least they belong to the same nuclear
system and can have a correlation distance of the order of nuclear diameter.

Thus it isinteresting to study competition between simEltaneous and successive transfer processes in theheavy-ion induced reactions. I), 2)
The transition amplitude can be written as(1)
We expand this to the second order of the interaction and take the same restricted class ofintermediate states m :
(2 )

1 .

.

Tfi = < fIVf 11 > + L:
< f IVf 1m > E - Hrn+.LC < mlVi 11 > ,m(2)

where Hm is the unperturbed Hamiltonian in the intermediate channel and Va is the residualinteraction in the a-channel. We refer each term of Eqn. (2) as the amplitude of the post or
prior-post form.

Due to the equality of the post and prior forms of the first order amplitude,

Eqn. (2) is equivalent to(3)

Eqn. (2) can be rewritten so as to involve < m Iv m Ii> instead of < m I Vi Ii>,
(2 )Tfi = < fl Vf Ii > - L:< fl Vf I m>< ml i > + 2:: < fl Vf 1i >mm

E - Jrn+ ic < mIVrn l i > .

(4 )If both the projectile and target systems can be described by the shell model within the given
space of m, the first term is cancelled with the second term 1) and we get the post-post form
(2 )
•
1
.
1> E - H + . < mIVrn ll > .
Tn = L:
<
f
IVf
I
m
rn lC

(5)

Starting from Eqn. (3) we get the prior-prior form :
(6)

59

The reaction 48Ca ct 60, 14C) sOYi to the lowest 0+, 2+, 4+, and 6+ states of sOYi at 58 MeV
incident energy3) has been analyzed in the no-recoil approximation. We have used the code
TWOST. 4) The optical pararrieters are taken from Ref. 3 : V = 37 MeV, rOR = 1.35 fm ,aR = 0.42 fm, W = 78 MeV , rO I = 1.27 fm, and aI = 0.28 fm.

Simple configurations are

assumed for 50Ti and 160 :< 14CI 16 0 > = (OPl /Z) Z, < 48CaI50Ti >= (Of7/ Z).z
The successive transfer is assumed to proceed via a channel m consisting of the ground states of
15N and 49SC.

The cross sections in various representations differ from each other by about

30 %. In Figs. 1 and 2 we have compared the experimental data with the results of calculation.
The normalization constants defined by N = 8 exp / 8 calc are listed in Table 1.

It can be seenthat the successive transfer dominates over the simultaneous transfer for all the transitions.

Itshould be noted that , although the two-step angular distributions for 4+ and 6+ transitions shownin Fig. 2 do not have oscillatory behavior, we can change them so as to fit the experimental
shape by varying the Q value for the first or second step while fixing the overall Q value.

1.0
0 .5
4+ , 2 .6 8 MeV

~O.I
..c
E

0 .1

2+ , 1. 55 MeV

1. 0
0. 5

o

6+, 3 .20 Me V

0.1

lL_~_,-l;,1_~_-='=I=_ - -' .-- :': :- - '0.0 1_-----L_--:=l::I

10

20

30

40

Sc.m.

Fig. 1. Angular distributions for the reaction
48Cae60, 14C) 5 0Ti leading to the lowest
0+ and 2+ states at incident energy of
58 MeV. The solid and dashed lines are
the theoretical curves predicted by theone- and two-step DWBA, respectively.

Sc.m.

Fig. 2. Same as in Fig. 1 except for thetransitions to the lowest 4+ and 6+ states.

60

Table 1. Normalization constant(N = 0 exp / 0 ca1)
c peak .
J1I"

E*(MeV)0+

None-step

Ntwo-step

0.0

250

12.5

2+

1.55

300

13.6

4+

2.68

330

22.8

6+

3.20

224

10

References
1)

R. A. Broglia, U. Gotz, M. Ichimura, T. Kammuri, and A. Winther: Phys. Lett., 45B, 23(1973).

2)

T. Kammuri: ibid., SIB, 442 (1974).

3)

W. Henning, D. G. Kovar, B. Zeidman, and J. R. Erskine: Phys. Rev. Lett., 32, 1015
(1974).

4)

M. Toyama and M. Igarashi: DWBA code "TWOST" (unpublished).

61

4-16.

CCBA Analysis of (p, t) Reactions on Rare-Earth Nuclei

M. Wakai,* M. Sano,* T. Takemasa, and S. Yamaji

Nuclear reactions are usually analyzed by using a zero-range DWBA method and it is a very
effective tool for study of the nuclear spectroscopy.

Some of the present authors (M.S. and T.T.)

and M. SakagamP) analyzed (p, t) reactions on rare-earth nuclei by using the zero-range DWBA
method.

They explicitly took into account of the difference between the deformation of atarget nucleus and that of a residual nucleus and obtained the following results: (1) the angular
distribution and the neutron number dependence of the ground state cross section are in good
agreement with the experimental results, (2) neither the magnitude of the cross section nor the
angular distributions for the 2+ and 4+ state transitions are well reproduced.

The finite range

2

calculations ) were performed by one of the present authors (T.T.) and H. Yoshida to dissolve
the discrepancy between the experimental and the theoretical results based on the zero-range
DWBA.

However the situation was not improved by introducing the effect of finite range of

nucleon-nucleon interaction.
Recently, the importance of the channel-coupling was emphasized and the CCBA method
was applied for analysis of (p, t) reactions. 3 )The CCBA calculations showed that the contributionof indirect processes is much larger than was expected and has an important effect on boththe cross sections and the angular distributions to make the agreement between the experimental
and theoretical results better.

It has led us to reanalyze the (p, t) reactions on rare-earth nuclei

by using the CCBA method.

The transition amplitude of CCBA for a transfer reaction A(a, b)Bis written as 4 )Here 'lIa(+) and 'lIb(-) are solutions of a coupled-channel equation and a = b + x.

We used thesource-term method developed by Glendenning S ) to get the transition amplitudes. In this analysis,
the coupling of 0+, 2+, and 4+ states of a ground band were considered.

The angular momentum

projection method is applied to obtain the nuclear wave functions of rotational states. I)
optical parameters used in the analysis are tabulated in Table 1.

The

Figures 1 and 2 show the6experimenta1 ) and theoretical angular distributions for 0+, 2+, and 4+ .transitions of 172Yb(p, t)
170 Vb.

It can be seen that the CCBA method reproduces well the forward ~eak behavior of2+ transition which the DWBA cannot expalin at all.

According to our calculations, an indirectprocess 0+ ~ 2+ transfe~ 2+ gives a large contribution and makes the value of the crosssection to 2+ state much larger.

The forward peak behavior of the 2+ transition is reproducedby the interference between the direct 0+ ~ 2+ process and the indirect process mentioned* Osaka University

62

Table 1.

Optical parameters used in the CCBA calculations.
Proton

TritonV(MeV)

51.4

150.0

r~ (F)

1.17

1.24

a(F)

0.73

0.67

W(MeV)

2.59

20.0

WD(MeV)

7.50

0.0

r~ (F)

1.31

1.46

a/(F)

0.65

0.79

~(F)

1.20

1.40

10 3

103

\72Yb (p,t) \7OYb

Ep = 51.7 MeV\72 Yb (p,t) 17C>yb

10

2

~.
,

.....:

0+....... "

f',

..!:?

.D

~

Exp (0+)!

Exp (2+ )10 2----- Col (2+)

It
~

~

2+

3-

CCBA

- - Col (0+)

'-',

+-'

-

£p = 51.7 MeV

3-

c:: 10 '

10\

~

~

"b

"-

~

~

... 1

10-1 !:--0

L-----=2l:-0-- - - L - - -L - - - - L - - -L - - - - L - - - - - 1

4O

6O

S0
Bcm (deg)Bcm (deg)

Fig. 1. Angular distributions for the g.s. and 2+
transitions.
above.

Fig. 2. Angular distributions for the 4+transition.

The summed cross sections o'CI+) are defined by the· sum of differential cross sections

taken for 5° steps in the range 5° - 45°, and the ratios o(l+)/o( 0+) are plotted in Fig. 3. The
DWBA calculations l } give the ratios 0(2+)/0(0+) = 5 '" 10% and 0(4+)/0(0+) = 1 '" 5%. They
are too small compared with the experimental values: 20 '" 40 % and'" 5 % for 2+ and 4+
transitions, respectively.

As is seen from Fig. 3, the CCBA calculations explain the experimental

63

-0--

60

Exp

- x - Col50--X~.--"_______X

- 40
~

-

+1+ 30Gd...... 0

Oy

2+

b b

20
4+

10

0

90

100

110

N

Fig. 3. The ratios a(2+)/a(0+) and a(4+)/a(0+)
as a function of neu tron number N.
values fairly well.

It is due to increase of a(2+) and a( 4+) which comes from the large

contributions of indirect processes.
The optical parameters used in these calculations are preliminary ones and may not bemost suitable.

A parameter search is now in progress to get optimum values.

References
I)

T. Takemasa, M. Sakagami, and M. Sano: Phys. Rev. Lett., 29 133 (1972).

2)

T. Takemasa and H. Yoshida: Phys. Lett., 46B, 313 (1973); T. Takemasa: Nucl. Phys.,A220, 31 (1974).

3)

T. Tamura, D. R. Bes, R. A. Broglia, and S. Landsdowne: Phys. Rev. Lett., 25, 1507
(1970); ibid., 26, 156 (1971); R. J. Ascuitto, N. K. Glendenning, and B. S¢rensen: Phys.
Lett., 34B, 17 (1971); Nucl. Phys., A 183, 60 (1972).

4)

S. K. Penny and G. R. Satchler: Nucl. Phys., 53, 145 (1964).

5)

R. J. Ascuitto and N. K. Glendenning: Phys. Rev., 181, 1396 (1969); ibid., e2, 415 (1970).

6)

Y. Ishizaki: Proc. Phys. Soc. Japan, 26, 147 (1971); Y. Sugiyama, 1. Kotame, T. Suehiro,
Y. Saji, H. Ogata, A. Stricker, I. Nomaka, and Y. Ishizaki: J. Phys. Soc. Japan, 30, 602(1973).

64

4-17.

Folding Model for Nucleus -Nucleus Optical Potential

K. Kammuri and T. Wada

A nucleon-nucleus or alpha-nucleus elastic scattering has been described successfully by afolding model, in which an optical potential is approximated by a convolution of the target
density with nucleon-nucleon or alpha-nucleon interaction.·)- 3)

Heavy-ion elastic scattering is

usually treated by a simple optical potential with Woods-Saxon shape. The optical parameters
show Igo's ambiguities. 4 ) With the aim of dissolving such ambiguities, we applied the folding
model to the heavy-ion scattering.
The real nuclear part of the optical potential is taken to be
V l d=~ dr, ~ dr2Pa(~ ) v ( ~ - ;;) PA (;:: ),where P a and P A are the projectile and target total densities, respectively, and veri an effective nucleon-nucleon interaction.

V c( r)= \ dr. \ dr2

J

J

r~)

is

Similarly the Coulomb part is given bypg (;; ) _ 1 _I r 1 - r~ I

where Pc means a charge density.

(1)

P ( r 2) ,(2)

AWe assume that the imaginary part was proportional to thedensity overlap of two systems,

27th2
\
\
W(r)= - ~ W J drl J dr2 pa ( rl ) pA ( r l - r) .

(3)

The coordinate vectors are shown in Fig. 1.
The form factor for the collective inelastic excitation can be derived from the folding
model.

Assuming that only the even mass target system is excited vibration ally , its surface isexpressed by
R = RA (1 + L a
Af.1

1

I\. ,UY

1

1\. /1( 8, 1> )) .

Fig. 1. Coordinate vectors.

(4 )

65

By substituting Eqn. (4) in to the density P A (r, R), we obtain the coupling potential;

V co upl ( r ) = L(- 1 ) Ie - '~ - P y Ie*p ( e,~ ) , v (' p, 1e ( r )
11 )

/1

leP

(5 )

where the complex form factor v~~ ,A (r) is given by
' 1)

\

2

v c P,1e ( r ) = 4 IT RAJ r 2 dr 2

(A )1J [ V err( f I f 2) -

.
I

2 ITn
( Ie )]-----rvrW pa ( f I f2 )2dPA ( f 2, R d + C ( Ie ) () dp~ ( f 2+ R\ ) )d RAe rr f I f 2
d RA

(6)

(A) ( rl, r 2 ).IS t h e A-thi'hfect!vef'. 'I e-target nuc1eon
H ere Veffmu
t!pO1e term 0 f tee
proJect!
interaction;( Ie )

1 \ 1

V err ( f I f 2) = 2

J _ 1 v err ( f ~) ~ ( cos w ) d ( cos w ),

(7 )

where

u, rr 1r ;) = ~ Pa l ~ ) u l ~ - ;:; ) d;;.

(8 )The Coulomb part C~1} (r 1, r2) was defined in the same way, and p ~A) is given by Eqn.
(7) by replacing v efrCr~) by Pa(r; ).
Here we report some results of analyses of the elastic scattering of high energy 14N.

/

/

150

/
/
/
/
/
/

200/
/

80

I

2.5

/
I

/
/

I
I

2.0

1.5

1.0

30

40

50

V l " leV )Fig. 2. Contour map of x 2 for the elastic
scattering of 84 MeV 14N on 27 AI.
Gaussian force with 1.22 fm range was
used.

An

66

ordinary optical model analysis was reported by Kohno et aI. S ) The contour map of x2 definedby(9)is shown in Fig. 2 for the scattering of 84 MeV 14N on 27 AI.
taken to be a Gaussian shape with the range 11 = 1.22 fm.
minimum point in this map.

The two-body interaction was

We can see that there is only one

By taking the shape to be Gaussian (11 = 1.5 fm), Yukawa(11 = 1.0 fm), or delta function, we have searched optimum values of two parameters, thestrength V of the two-body force and the imaginary strength W by use of "SEARCH" code
written by one of us?)Shapes and parameters of the density distributions were taken from theresults of electron scattering,7)

(lOa)
(lOb)
97 MeV

14N

on

92 Mo

10- 1
a::

b
'b

10- 2

10

20
() c.m.

Fig. 3. Optical model analysis of the elastic scatteringof 97 MeV 14 N on 92 Mo. Solid line is thefolding model prediction. Dotted line is a
curve calculated by use of the ordinary opticalpotential with parameters; V = 100 MeV, W =25 MeV, r 0 = 1.13 fm, re = 1. 2 fm, and a =0.5 fm.

67

Table 1.

Folding model parameters for the elastic scattering of 14N.
(Projectile density is given by [1.03, 1.67])

E

Target(MeV)

density

8-force

Gaussisn (1.5 fm)

Yukawa (l.0 fm)

~

~

~

V
W
(MeV) (MeV)

VW(MeV) (MeV)

VW(MeV) (MeV)

14N + 12C

65

[ 1.057 , 1.33]

18.28 4.73

15.92

5.00

4.93

1.00

14N + 27AI

65

[1.02, 0.52, 0.0]

10.81

1.39

7.87

0.87

3.39

1.66

14N + 27Al

84

[1.02, 0.52, 0.0]

14.35

1.86

14.27

2.08

3.03

1.51

14N + 28Si

84

[1.02, 0.52, 0.0]

14.59

2.09

13.67

2.00

4.58

2.67

14N + 58Ni
14N + 92Mo

84

[1.124,0.5, - 0.185]

8.94

0.62

7.78

0.58

2.47

0.41

97

[1.073, 0.52, 0.0]

10.50

1.44

8.62

1.10

2.49

1.04

where W = 3 a (2 + 5 a) / 2 (2+ 3 a).

In Table 1, the density parameters are denoted by[ro , a, Wj for Eqn. (10a), or by [ro , aJ for Eqn. (lOb).

It should be noted that the strengths

V given by other sources such as (p , pi ) are around 20 MeV for the Gaussian force (p. = 1.5 fm)
and 30 MeV for the Yukawa force (p. = 1.0 fm).8) Finally in Fig. 3, experimental
angular distribution for the case of the elastic scattering of 97 MeV 14N on 92Mo is comparedwith the predictions of the folding model and ordinary optical mode1. 9 )References
1)

G. W. Greenless, G. J. Pyle , and Y. C. Tang: Phys. Rev ., 171, 1115 (1968).

2)

P. Mailandt, J. S. Lilley, and G. W. Greenless: ibid., C8, 2189 (1973).

3)

B. Tatischeff and I. Brissaud: Nucl. Phys. , A 155 , 89 (1970).

4)

G. Igo: Phys. Rev. Lett., 1, 72 (1958).

5)

I. Kohno, S. Nakajima, T. Tonuma, and M. Odera: J. Phys. Soc. Japan, 30,910 (1971).

6)

T. Wada: Reports I.P.C.R. (in Japanese) , 46, 21 (1970).

7)

J. P. Vary and C. B. Dover: Phys. Rev. Lett. , ll, 1510 (1973).

8)

S. M. Austin: "The Two-Body Force in Nuclei" , Plenum Press, N. Y. London , p. 285 (1972).

9)

I. Kohno: Private communication.

68

4-1 8.

Role of the

12

C-Core Exchange in the

16

0-

12

C

Elastic Scattering

H. Yoshida
The elastic scattering of two heavy ions which have identical cores with few nucleons outsideof one of the cores generally shows the backward rise in the angular distribution.

This backward

rise of the angular distribution can be understood reasonably well as the transfer process of theouter nucleons superposed on the shape elastic process. 1) - 8)

The reactions considered here are

the following processes:

A+ (B + X) ........................ (D )( B~ X ) + A-- 1B + (A; X ) ........................ (E)bReaction (D) is a direct shape elastic process and reaction (E), where the identical cores A and B
are exchanged, is a transfer process of the cluster X.

To take account of the both processes

simultaneously, the total wave function 'Ir properly antisymmetrized with respect to the interchangeof the identical cores A and B was used:(1 )Here the function X (r a) describes the relative motion of the colliding particles a and A, andI aA> describes the intrinsic states of the two particles.

The equation for the L-th partial waveof X (rb) is obtained from the total Hamiltonian as follows:

(2 )

Here

(3a )

69

Dependence of the calculated cross sections on the nonnalization constant N which

Table 1.

can be regarded as the coupling strength of the · transfer channel.

8c~

1.0

1.5

2.0

2.5

0

0.58

0.56

0.56

0.55

1460

0.25

0.22

0.20

0.20

0

2.21

2.34

2.25

2.06

0

2.01

l.67

1.45

l.29

166

172
156

O'eal (8 )/ N

2}

EL = 65 MeV}

EL = 24 MeV(mb / std

are not large for incident energies above the Coulomb barrier, showing that the effect is not very
important. 4 )-S)

In fact, we can see from Table 1 that the calculated cross sections at EL =65

Me V increase roughly with N2 near the shell model limit (N= l.0) in consistence with the DWBA
prediction.

But the cross section at the second peak 8 c.m.=156° of EL =24 MeV shows adeviation from the N 2 -dependence.

The multistep transfer process plays a role in this case.

1.0

O.It
~

'--

I. = II

;;

! 1.0

c:

"0

'-b

"0

0.1

.;;

\

\

\L = 8\

L = 10Fig. 2. Comparison of the results calculated by

Fig. 3. The local approxImation potential U L (rb )the local approximation (dashed lines)

for several L-values. The non-orthogonality

with those of exact calculations (solid

term KLI) (r b , ra) is not included here.

line ).

70

The normalization constant N is introduced to the r.h.s. of Eqn. (2) so that the calculated
values of the cross section may reproduce the experimental values at backward angles and J is
The spectroscopic factor SNL in Eqn.
(3b) is calculated by assuming the configurations p12 [444] llS and p8 [44] llS for 16 0 and 12C
the Jacobian of the transformation to the coordinate ra.

states respectively.

Eqn. (2) is solved numerically obtaining the angular distributions.

solution includes the multistep transfer process.
to see the multistep transfer effect.

The results are compared with those of DWBA

As shown in Fig. 1, the differences from the DWBA results

l.0

0.1

~

~

"..D

~

The

l.0

~

"b
-0

Fig. 1. Comparison of the present calculations(solid lines) with those of DWBA (dashedlines). The angular distribution obtainedby use of the optical potential Db (r b )only is drawn by a solid and dotted line
at EL = 24 MeV in order to show theimportance of the interference with the
DWBA amplitude. Parameter values ofthe optical potential are V = 30 MeV,
W = 10 MeV, a R = 0.8 fm, a I = 0.45 fm,
r R = 1.2 (E L = 24 MeV), 1.13 fm (E L =65 and 80 MeV) and r I = 1.15 fm. The
normalization constant is N = 1.0 for
EL = 24 MeV and N = 1.5 for EL = 65
and 80 MeV.

71

At low energies, the r.h.s. of Eqn.(2) can be approximated by UL (r b)x L (r b) where thelocal approximation potential U L (rb ) is given by(4)

since the partial wave

XL (r)

changes more slowly than the kernel KL (rb , r a ).

In fact, angular

distributions calculated using the above approximation are similar to those obtained by the exact
calculations at low energies (Fig. 2). The potential U (r ) shows the parity dependence 2) asLshown in Fig. 3.

b

The potential is very much affected by the presence of the non-orthogonality

term KL (1) (rb , ra) in Eqn. (3) especially for lower partial waves and in nuclear interior regions.
But the calculated angular distributions remain unchanged whether the non-orthogonality term
is included or not (Fig. 4).
All the calculations have been performed so far by assuming the a-cluster transfer witha spectroscopic factor of S20 e60~12C+a) = 0.296 obtained from configurations p12 [444] andp8 [44] for 16 0 and 12C states respectively. The above choice of the configurations, however,predicts the existence of the a *-clusters in nuclei.

Preliminary calculations show that the

a*-clusters does not affect the angular distributions at low energies but at high energies theangular distributions are shifted to the backward angles.

A further study on the effect of the

1.0

0.1

120

160

140

180

ec. \ 1

Fig. 4. The effect of the non-orthogonality termon the angular distributions. The results
calculated with and without the
non-orthogonality term are shown by
the solid and dashed lines respectively.

72

a *-clusters is now in progress.

References
1)

A Gobbi, U. Matter, J ,-L. Perrenoud, and P. Marmier: Nucl. Phys., A 112, 537 (1968).

2)

W. von Oertzen: ibid., A148, 529 (1970); W. von Oertzen and W. Norenberg: ibid.,
A207, 113 (1973); H. G. Bohlen and W. von Oertzen: Phys. Lett., 37B, 451 (1971).

3)

C. K. Ge1bke, R. Bock, P. Braun-Munzinger, D. Fick, K. D. Hildenbrand, A. Richter, and
W. Weiss: Phys. Rev. Lett., 29, 1683 (1972); K. D. Hildenbrand, R. Bock. H. G. Bohlen,
P. Braun-Munzinger, D. Fick, C. K. Gelbke, W. von Oertzen, and W. Weise: Phys. Lett.,
42B, 425 (1972); C.K. Gelbke, R. Bock, P. Braun-Munzinger, D. Fick, K. D. Hildenbrand,
W. Weiss, and S. Wenneis: ibid., 43B, 284 (1973).

4)

C. A. Mcmahan and W. Tobocman: Nucl. Phys., A202, 561 (1973).

5)

G. Baur and C. K. Gelbke; ibid., A204, 138 (1973).

6)

B. Imanishi: Preprint and private communications.

7)

C. K. Gelbke, G. Baur, R. Bock, P. Braun-Munzinger, W. Grochulski, H. L. Harney, and
R. Stock: Nucl. Phys., A219, 253 (1974).

8)

G. Baur and H. H. Wolter: Phys. Lett., 51 B, 205 (1974).

73

5. NUCLEAR PHYSICS
Nuc lear Spectroscopy
5-1.

lifetime Measurement of the 6~46(2976 keY) State in

Ca and+2

E2 Effective Charges in (1 f 7/)-

NucleiW. Kutschera, G. D. Sprouse, H. Ikezoe,
Y. Yamazaki, and T. Nomura
The mean lifetime of the first excited 6+ state in 46Ca has been measured with the pulsed
beam method to be Tm= 15.2 ± 0.8 ns. The state was populated via the reaction 48Ca(ex, ex2n)46Ca with 50 MeV ex particles from the cyclotron.

Electronic timing was performed between

the natural beam bursts of the cyclotron and ')'-rays observed with a Ge (Li) detector.

Experimental

details are described in Ref. 1.
Table 1 summarizes the present experimental information!) on E2-decay properties of the2+, 4+, and 6+ states in Of7/2 )±2 nuclei.

The last column gives the additional charges 0 e = eeff

-1 for protons and 0 e = eeff for neutrons.

The effective charges have been extracted from therelation:

Here, the theoretical B (E2) values have been calculated with pure 0 f7/2 )±2 configurations andharmonic oscillator wave functions.
The strong state dependence of the effective charges for 42Ca and 42Ti indicates large
admixtures of other configurations in the 2+ and 4+ states of these nuclei.

On the other hand,the 6+ -+ 4+ transitions in 42Ca and 46Ca are rather close to each other. Using the more refined wave
functions of Ogawa,2) who considers (p3/2f7/2)2 and (P3/2 f7/2)6 configurations, one obtains
a remarkable constant value of the neutron effective charge for the 6+ -+ 4+ transitions in 42Ca
and 46Ca: eeff (6+ -+ 4+, 42Ca) = 0.69 ± 0.01 e and eeff (6+ -+ 4+, 46Ca) = 0.68 ± 0.02 e.
These values should be close to the neutron core polarization charge in this mass region.

It isinteresting to note that this value is close to the macroscopic estimate of Bohr and Mottelson: 3)
epol (neutron) = (Z/A+0.29) e =0.72 e.

The three proton nuclei 42Ti, 50Ti, and 54Fe are difficult to compare with each other,since i) 42Ti shows an exceptionally low effective charge for the 6+ -+ 4+ transition, and ii) the
extraction of a reliable proton charge for the N = 28 isctones involves the more complex
excitation of both protons and neutrons to other f-p orbitals in order to obtain wave functionsof good isospin.

(vf7 / 2r 2

(1Tf7/ 2 )2

(1Tf7/ 2 )2

(1Tf7 / 2r 2

igCa26i~ Ti 20~gTh8~~Fe28409

6+ -+ 4+1408

2+ -+ 0+1131

524

6+ -+ 4+4+ -+ 2+1121

4+ -+ 2+II
1554

2+ -+ 0+b ) oe= eeff -1 for protons and oe = eeff for neutrons.

l.75 ± 0.03 ns

5.7 ± l.2

l.38 ± 0.10

0.61 ± 0.02 ns

7.7 ± l.5

1.4 ± 0.2

26 ± 5 ns± 0.9

40.7 ± 0.7

77 ± 16107 ± 833.8 ± l.2

60 ± 1266 ± 84.7

366

1.00 ± 0.02

0.85 ± 0.19

1.18 ± 0.08

0.87 ± 0.04

0.68 ± 0.17

0.76± 0.11

-0.26 ± 0.07

<2.5(6+)-+ (4+)

<230

1121

> 1.8

1.8 ± 0.3

150 ± 25

0.60 ± 0.10

1555

2+ -> 0+(4+)-+ 2+

l.32 ± 0.07
< l.1
0.76 ± 0.02

35.1 ± 3.6<230.86 ± 0.01

5.31 ± 0.28

not measured

5.24 ± 0.54
>8

6.42 ± 0.11

1.85 ± 0.10

2.09 ± 0.02

15.2 ± 0.8 ns1346

2+ -+ 0+7.79 ± 0.13 ns

65 ± 7'83.4 ± 2.8(e)o eb )

399

439

6+ -+ 4+4.5 ± 0.5

l.19 ± 0.04

(e 2 fm 4 )

B (E2)

6+ -+ 4+1227

4+ -+ 2+

a)

1231

1524

2+ -+ 0+

m

(ps)

T

4+ -+ 2+

I

(

I

E')'
(keV)

Transition

E2-decay properties of 2+, 4+, and 6+ states in (lf7 / 2 )±2 Nuclei.

a ) Averages of the values taken from various experiments.

(Vf7/2)2

configura tion

i5 Ca22

Nucleus

Main

Table l.

-...]

+:>.

75

References
1)

W. Kutschera, G. D. Sprouse, H. Ikezoe, Y. Yamazaki, and T. Nomura: Phys. Rev. Lett. (in press).

2)

K. Ogawa: Private communication.

3)

A. Bohr and B. Mottelson: Nuclear Structure, Benjamin, New York, Vol. II Chapt. 6

76

5-2.

High-Spin State Yields

88

In

Y Relative to 1 + State90
In

Nb Excited

via 89 y + a

Reac tion

A. Hashizume , Y. Tendow, T. Katou, and H. Kumagai
A natural yttrium target was bombarded with a-particles and the 382 keY 0+) state in
90Nb was excited via the 89Y(a, 3n) reaction.

In these experiments, the beam from Cyclotron

was passed through a mechanical beam chopper and, using a pulsed beam technique, the half-lifeof the 382 ke V state was determined to be 6.19 ± 0.08 ms.I)
During the course of the study , in the delayed ,),-ray spectra, there were observed two 232
and 443 ke V ,),-rays, both decaying with a half-life of 14 ms (Fig. 1). These ')'-rays were
attributed to the cascade transitions from the 687 keY state to the ground state through the
231 keY (5- ) state in 88y.2)

Figure 2 shows the relative excitation functions of those ')'-rays

together with the 258 keY ,),-ray emitted from the above mentioned 9omNb. Because the Q valueof 89Y(a , an)88y is lower than that of 89Y(a , 3nt oNb , the isomer 88my was conjectured to be

•

o

E

N

N

;:!;

•

.
-::5

N

;:::;

<D

'"E

~ %

1 ~-

~~r
'"
~

0:::

\. ~
40 - 80m s•

200

90 :\ b- 90 Ll'

400

Cha nne l numbe r

Fig. l. Delayed ,),-ray spectra observed by bombarding
a-particles on 89Y.

600

77

1o 5 , - - - - - - - - - - -- - - - - - - -- - - - - -- - - -- -- -- -- - - -- .

t 232.1 ke V ( 88 Y )~443.4 ke V ( 88 Y )!

257.9 keY (90Ill Nb )/,+------+--,+~,

10 '--::'":
20:-----~2::':5------3-'-0------~-----4L
O - --------.l45--M--.J
eV
1Fig. 2. Relative excitation functions taken by 257.4 keY
r-rays in 90Nb, and by 232.1 and 443.0 keY in 88y.

produced by the former.

The yield ratios Yea, an: 687 keY)/Y(a, 3n: 382 keY) were found as

shown in Table 1. Corrections were made for half-lives and for conversion coefficients of r-rays
assuming 257.9 keY and 443 keY as E3 and 231 keY as MI.

Because the spin and parity of

the 382.1 keY state is 1+ and the 687 keY state is considered to be 8+, such a large yield of
the metastable state in 88m Y will be partly explained by its high spin, as the change of angularmomentum from the compound nucleus is smaller than the transition to the state in 90rnNb andthis small change of angular momentum facilitates to feed the state in 88rny.
Table 1.

Yield ratios of the 687 keY (8+) state in 88y to
the 382 ke V (1+) state in 90Nb.

Energy (Me V)

32.5

35.0

37.5

40.0

42.5

45.0

47.5

11

5.1

3.3

(4.6)

3.0

3.5

3.5

78

References

1)

A. Hashizume, H. Kumagai, Y. Tendow, and T. Katou: Nucl. Instr. and Meth., 119,209 (1974).

2)

A. M. Morozov and V. V. Ramaev: Soviet Phys. JETP, !.i, 314 (1963).

79

5-3.

Short Life Radioisotopes and Isomers Observed vIa I r + C Reactions

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

In the region of nuclei whose mass numbers lie between about 190 and 210, many
isomeric states have been found because high spin orbitals such as h ll / 2 and i l3!2 are concernedwith those states.

With the aid of a beam bunching technique reported previously /),2) theradioisotopes and/or isomers of the half-lives in the ms region produced by the reaction 191Ir + C
and 193Ir + C were studied.
Powders of natural Ir and isotopically enriched 191Ir were used as targets.

A 50 cm3 Ge (Li)and a pure Ge detectors with high resolution (600 eV at 122 ke V) were employed for thedetection of '}'-rays.

These detectors were placed at 90° to the direction of incident beams.

Gamma-ray spectra in the delay-time range from about I ms to 1000 ms after the irradiation
were studied as well as long lived residual activities. The excitation functions for -y-rays fromIr + C reactions with incident beam energies from 65 to 95 MeV were also examined.
Figure I shows the ,},-ray spectra produced by the bombardment with C (95 MeV) on Ir
and 191Ir.

In the case presented in this figure, the targets were bombarded for about 60 ms,

and after 50 ms from the end of irradiation ,},-ray spectra were taken by 4 (times) X 1024
(energies) channels for 800 ms. The irradiation was restarted after 100 ms delay from the endof the ,},-ray measurements, and the same procedures were repeated.

At a bombarding energy of

95 MeV, the (C, 5n) reaction was predominant and intense '}'-rays emitted in the ground state
decay of 200Bi to 200Pb together with de-exciting 428.2 keY -y-ray from the isomeric state in
200Bi (T 1I2 = 0.4 S)3) were observed.

Owing to the 191Ir(C, 5n) reaction, a 248.5 keY isomerictransition (T 1/2 = 7.7 s) in 198Bi was also confirmed. The peaks corresponding to 197.6 and
317.9 keY are due to the ground state decay of 198Bi to 198Pb. According to the preliminary
measurements, the half-lives of 222.6 and 385.8 keY -y-rays were about I s.

As the isomer

at 609.3 keY in 197Tl emits 222.5 and 386.7 keY -y-rays, these delayed -y-rays would be attributed
to these transitions and the relative excitation curves for the (C, 5n) reaction shown in Fig. 2
are not qualitatively contradictory to the (C, a 2n) reaction.
on the value of -y-ray energy and the half-life.

However, there are some discrepancies

Further, if the metastable state is excited throughthe 191Ir(C, a 2n) 197TI reaction, there should be comparable feeds to the 748.5 keY (T1!2 =28.7 ms) state in 199TI through the 193Ir (C, a 2n) 199TI reaction.

We could not find any -y-rays

corresponding to the de-exciting transitions from the isomer decaying with such a half-life.
Further investigations is in progress comparing the Ir + C with Re + Nand Ir + B reaction toreveal the true origin of the two '}'-rays and to establish the quantitative relations between isomers
and isotopes produced in the 191, 193 Ir + C reactions.

~o

191 1r

+C.

<1>

c::
c::
C

.s::
U

.......
<I>......
c::

::>

o
U

650"'850ms

Kex

Ir + C
-

(/)

O'l

'"
M

J

'"I

I

-<1>
c::
c::

o

.s::
U

'-

'"c::
::l

o
U

650"'850ms

o

200

600

400
C han ne I

800

n umbe r

Fig. 1. The 'Y-ray spectra from RI and isomers produced by 191 Ir + C and nat Ir + C
reactions measured with a pure germanium detector. Energy values and assignmentfor 'Y-rays are given above the spectra with 198 Bi --+ 198 Pb ( 0 ), 199 Pb --+ 199 TI (.),
200

Bi --+ 200 Pb ([; ). The ordinate is arbitrary scale.

81

lr + C
Q)

a

~

I

10°

Q)

.~

-

-0
Q)

0::
if)

>-.

o

~
>

Q)

..os::.

~ 10- 11<:;j2222.6keV
385.8 keV

if)

!

o
-+--'

o

0::

10-~LO--------~8~0--------~9~O--------~1~00
ECllob l(MeV)Fig. 2. Excitation curves for 222.6 and 385.8 keY),-rays relative to 428.1 keY eOomBi) ,-ray.

References

1)

A. Hashizume, Y. Tendow, T. Katou, and H. Kumagai: IPCR Cyclotron Prog. Rep., 1, 79(1973).
2)

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

Nucl. Instr. and Methods, ill, 209(1974).
3)

U. Hagemann, K. H. Kaun, W. Neubert, W. Schulz, and F. Stary:( 1972).

Nucl. Phys., A 197, 111

82

5-4.

Monopole Effective Charges

T. Suzuki

Much has been written on the importance of electric and magnetic core-polarization
phenomena in nucleus. 1)

In particular, the effects of electric quadrupole and magnetic dipole

polarizations are extensively studied.

The former is illustrated by the electric quadrupole moments

and transition probabilities associated with the single-neutron configuration,l),2) while the latter isrecognized from the deviation of the observed magnetic moments from the Schmidt values. 1 ),3)
Their effects are usually expressed in terms of a renormalization of the charge or spin g-factorof the valence-nucleons, that is, a quadrupole "effective charge" or an "effective gs-factor" .1)
On the other hand, the change in the charge radius of a nucleus induced by the additionof another neutron is systematically observed throughout the periodic table, as is well known as
isotope shift. 1),4) This phenomenon is interpreted to be due to a monopole core-polarization
effect, which may be expressed in terms of a monopole effective charge. 5 )The core-polarization charges can be estimated in terms of the coupling of an extra particle
with the collective vibrations of the core.

A large part of the electric quadrupole polarization

charge (the polarization gs-factor) is considered as coming from the virtual excitation of theelectric quadrupole state (the magnetic dipole state) of the core whose excitation strength
exhausts a large fraction of the classical energy-weighted sum rule value. 1 )-3),6)

Indeed, recently,

such collective states have been observed in the continuum region through electron and hadronscatterings. 7)

The existence of a collective monopole state, which carries most of the classicalenergy-weighted sum rule value, is also expected in a nucleus as pointed out by many authors. 5),8)
We have studied monopole effective charges, which are interpreted as resulting from thevirtual excitation of such a collective state in the core.

The eigenfrequency of the monopole

vibration and the interaction Hamiltonian between a particle and the vibration are obtained bymaking use of various sum rules. 9 )The isoscalar and isovector monopole polarization charges

are estimated to be O.125e and O.0645eT3, respectively.

Isotope and isotone shifts calculated by

employing these effective charges are in good agreement with experimental results.

A large partof the Nolen-Schiffer anomaly can be also explained in terms of the isovector monopole
polarization charge.

References"Nuclear Structure", Benjamin, New York, 1 (1969).

1)

A. Bohr and B. R. Mottelson:

2)

H. Horie and A. Arima: Phys. Rev., 99, 778 (1955); S. Fallieros and R. A. Ferrell: ibid.,83116, 660 (1959).
3)

R. J. Blin-Stoy1e: Proc. Phys. Soc., A66, 1158 (1953); A. Arima and H. Horie: Progr.
Theor. Phys., 11,509 (1954).

4)

L. R. B. Elton:"Nuclear Sizes", Oxford University Press, Oxford, (1961); Y. N. Kim:

"Mesic Atoms and Nuclear Structure", North-Holland, Amsterdam (1971).
5)

R. W. Sharp and L. Zamick: Nucl. Phys., A208, 130 (1973); T. Suzuki: Preprint.

6)

T. Suzuki: Phys. Rev., C8 , 2111 (1973).

7)

R. Pitthan and Th. Walcher: Phys. Lett., 36B, 563 (1971); S. Fukuda and Y. Torizuka:
Phys. Rev. Lett., 29, 1109 (1972); M. Nagao and Y. Torizuka:
M. B. Lewis and F. E. Bertrand:

ibid. , 30, 1068 (1973);

Nucl. Phys., A 196, 337 (1972); Y. Torizuka: Proc.

Intern. Conf. Nucl. Structure Studies Using Electron Scattering and Photoreaction, Sendai(1972); E. Spamer: ibid.; L. W. Fagg: Proc. Intern. Conf. Photo nuclear Reaction andApplication, Asilomar (1973); Y. Torizuka: ibid.; M. B. Lewis: ibid.; Th. Walcher:Proc. Intern. Conf. Nucl. Phys., Munich (1973).
8)

J. Blomqvist: Nucl. Phys., Al03, 644 (1967); J. Damgaard, V. V. Gortchakov, G. M.
Vagradov, and A. Molinari:Nucl. Phys., A121, 625 (1968); L. Zamick: Phys. Lett., 31B,

160 (1970); N. Auerbach:Nucl. Phys., A 182, 247 (1972); R. W. Sharp and L. Zamick:ibid., A223 331 (1974).
9)T. Suzuki and C. Hinohara: Phys. Rev., C9, 1186 (1974); T. Suzuki: Nucl. Phys., A220,
569 (1974).

84

6.

NUCLEAR INSTRUMENTATION

6-1.

Performance of the IPeR Polarized lon-Source

S. Motonaga, T. Fujisawa, M. Hemmi, H. Takebe
K. Ikegami, and Y. Yamazaki
A polarized ion-source was successfully operated on the test bench and is now being
installed in a cyclotron. The performance of the polarized ion-source was described.
( I)

General description

The general design and overall components of the IPCR polarized ion source were describedin previous reports. I)

The source is based on the atomic beam principle.

Radio frequency

transitions followed by strong field ionization are used to produce a maximum obtainable nuclear
polarization.

General arrangement of the source is shown in Fig. I schematically.

The hydrogenor deuterium molecules are dissociated in a pylex bottle by an rf discharge at a frequency of
20 MHz.
blast.

The power dissipated in the discharge is 250 W.

The pylex bottle is cooled by air

Dissociated atoms diffuse through a single nozzle of inside-diameter of 3.5 mm andlength of 10 mm into a sextupole magnet.

The electron spin states of the atoms are separated

in the field of sextupole magnet having a tapered aperture from 6.5 to 13.0 mm along its axisof 35 em and producing a maximum field strength of 7.2 k gauss at pole tip radius.

The atomic

beam polarized with respect to the electron spin is subjected to a high-frequency electromagnetic
field which induces transition by adiabatic passage 2 ) and then ionized by electron impact in thestrong magnetic field.

011 diffus ion pump( 800 ilsec)

I on pump(125 ilsec )SEXTUPOLE MAG NET

DISSOSIATOR
Py re x tube; 35mm , 1.0.
RF-po wer ; 20M Hz ,200WNozz le; 3,5mm, 1.010mm , 1.0.
Coilime t er ; 4 , 5 mm, I.O.

Q. = 0.25 t orr. l/sec

P= 2x 10- 5 torr

Apertu r e. ent rance; 6,5mm
exit; 13 mm; 350 mmLeng t h; 7200 ga uss
Bmo x;6mm,O.0.
Coi l
8 turn s/poleRF
TRANSITION<J2 - 63- 5
380 MHz, 16 W
B; 40 , 117 gous st.8 ;5 ,15gouss

IONIZERACCE L- TUBE
120kV

B; 150 0gausslonlzot ion electrod
lO mm, I. O. , 145mm L

P=4XI0- 7 torr.

o

20

I

30

Fig. 1. General arrangement of the polarized ion source.

40, , '" I ,Sco le [ em )

50

"I

85

Two medium field transitions are used enabling different nuclear polarization states to be
selected in a simple manner.

For deuterium both transitions of 3 to 5 and 2 to 6 are available

at a frequency of 380 MHz, with static fields at 40 and 120 gauss, respectively.

Thesetransitions are done separately to obtain tensor polarization of P zz = -1 (3 to 5) and P zz = + 1(2 to 6).

Best measured neutron anisotropies N (0° )/N (90°) from the T (d, n) 4He reaction are

0.657 and 1.418 corresponding to Pzz = +0.516 and -0.562.
(2)

Measurement

The intensity of the atomic beam at the entrance to the ionizer was 3 X 10 1S atoms/cm 2 • sec
measured by means of the compression tube method using an ionization gauge.

Pictures on

Mo0 3 targets placed at about 35 cm apart from the exit of the sextupole magnet showedfocusing and separating effects for the electron spin states.
The efficiency of ionization of the ionizer was observed by adding hydrogen gas into theionizing chamber and measurering the increase in the extracted ion beam current.
3

was 4 X 10- •The efficiency

Although this is not equal to the efficiency of ionizing an atomic beam because

the mean velocity of the atoms is higher than in the present measurement, it can be used forcomparative measurement.
The emittance of beam extracted from the ionizer was not measured.
of ion beam seems to be not so large.

However, divergence

The beam spot at a distance of 60 cm from the extraction

electrode in the ionizer was found less than 40 mm in diameter.
The ion beam intensity of 1 I1A was observed on optimum operation as the difference of thecurrents at the end of the accelerating tube when the sextupole magnet was turned off and on.
For several hours of operation the beam intensity of 0.6 I1A was maintained stably.

Therefore,

the intensity of 5 nA should be obtained at the target when the source is installed in a cyclotron
whose overall efficiency of injection, acceleration, extraction and transportation of beam is about%.
The tensor polarization of the deuteron beam was measured by the neutron anisotropic
factor on the T (d, n) 4He reaction as described above.

The differential cross section is

independent of the vector polarization of the beam and for a deuteron having the tensor component
Pzz 3) it is given by(jpol (e)= (J"unpol [1 - ~ P zz (3cos 2 e-I)],

where () is the angle between the spin quantization axis and the emitted neutron in the systemof the center of mass.

Two plastic scintillators where placed at 0° and 90° with respect to thebeam direction and were 50 cm apart from a Tritium-Titanium target to detect emitted neutrons.
The ' asymmetry is of the form:

where a is the cross section and N is counts of the emitted neutrons.
measured as a function of the static field Be at a fixed frequency.

The asymmetry was

For a frequency of 380 MHz

86() 3~5

1.40

,f1H\

1.30

,;1 f Ili

1.20

0

Q)

z

;f

1.10

.::::::/

0z

Pzz =-0.562:t0.071

/

1.00

0.

\

~

\
\
\

"§ 0.90
co
<I:

f f
I

\

0.80

\i

it'

0.70

\
\
\

\

>,

i

I

\'

()Z-6

Pzz =+0.516:t 0.058

0.60

40

50

1
70

60

v"-;-ll~
1 0:----'--1:7-=-0---'----:-13=-=
10:---'---.1.- ---1----1
140
150

2

Be (gauss)

Fig. 2. Neutron anisotropy in the T( d, n)4 He reaction withpolarized deuterons.
the static field was varied in the regions from 40 to 150 gauss in order to investigate thebehavior of the 2 to 6 and the 3 to 5 transitions.

The results are shown in Fig. 2. The

maximum values of the asymmetry measured wereR = 0.657 ± 0.034

for 2 to 6

R = 1.418 ± 0.69

for 3 to 5,

corresponding to
Pzz = 0.516 ± 0.058 for 2 to 6
Pzz = - 0.562 ± 0.071 for 3 to 5.
These values include only a correction for detector background with no beam on the target.
It is wellknown that an unanalyzed beam contains unpolarized D2 + components which dilutes
the measured polarization of the atom.
sharp for the 2 to 6 transition.

The maximum peak of the polarization is relatively

The 3 to 5 transition, however, shows a broad top in which

the static field can be varied without losing the polarization.

In both cases the slopes werequite steep. Since the values of the asymmetry of the 3 to 5 transition are not criticallyaffected by the drift of the field, this transition should be chosen in connection with the weak
field rf transition in order to change the sign of the polarization in case of operation in theaccelerator.

Table 1 shows parameters of rf transition and polarization.

To investigate the efficiency of transition probability for various strengths of the rf
rotating field B 1, the neutron anisotropy was measured as a function of the rf rotating field87

Table 1.
# 1
Tra.n sition

Particle

RF-transition parameters.

Frequency(MHz)

Staticfield(gauss)Gradient
llH

10

8

2

1T I, 2, 3

# 2Transition

Frequency
(MHz)

1480

02 , 410

11

10

static field is perpendicular to rf fields.

a:static field is parallel to rf fields .

(} 12to6)

Fr eq uen cy

150

I

+ 1

5

_2

3

11

1T:

Polarization
Pzz Pzz

03, 5

378

117

5

0
3 '
1
+3. - 1

03 , 5

378

117

5

-3' - 1

3

Deuterium
1Tl,2 , 3, 4

GradientllH-

HydrogentTl , 2, 3, 4

Staticfield(gauss)1

Trans ition: 380 MHz

St at ic fi eld: 54 ga uss
Gradien t
1. 20

g 1.10...... 1.00

o

: ± 2.5 gauss

8 , = 2 .3 gauss

8 , = 2. 1 gaus s-i--L --1-

ti it:; 0.90

J

I

I

I

I

\I

\ ,f

:~/'

\i

\

\I

0.80

~ 0 .70

«

1

0.60

40

60

80

40

60

8e

8 ,=0.21 ga uss

8 , =0 .8 ga uss

40

\
I
\ I
\ I
\ I

I

\ I

\1/

I

60

(G auss I

Fig. 3. Neutron anisotropy for different strengths of rf rotating field.

which was varied from 0.21 to 2.3 gauss at 380 MHz.

As shown in Fig. 3, remarkable increasein the asymmetry was not observed.

The polarization values are smaller than the theoretically expected maximum values.
suggests that there is a possibility of improving our apparatus.

This

Perhaps the simplest way is todecrease the partial pressure of the deuterium gas in the ionizing region.
Also the most important problem is to increase the ion beam intensity.

For the present

ionizer of the source,l) a gridded electrode used to focus and accelerate the ion beam is a meshmade of stainless steel wire of 0.15 mm in diameter and 0.55 mm in pitch.

Although thepresent transparency of the ion beam through the gridded electrode is 47 %, the increase of thetransparency can easily be achieved.

Another improvement is to put the ionizer as near to theexit of sextupole magnet as possible.

By making these improvements, the ion beam of 2 fJ.A or

more could be expected.

88

References
1)

S. Motonaga, M. Hemmi, T. Fujisawa, and Y. Yamazaki:

IPCR Cyclotron Progr. Rep.,

4, 100 (1970); S. Motonaga, T. Fujisawa, K. Ikegami, H. Takebe, and M. Hemmi:
6, 12 (1972).
2)

A. Abragam and J. M. Winter: Phys. Rev. Lett., 1, 374 (1958).

3)

A. Galonski, H. B. Willard, and T. A. Welton:

ibid.,~,

349 (1959).

ibid,

89

6-2.

Investigation of Residual Gases in the Ionizerof Polarized Ion Source

K. Ikegami and H. Takebe

Polarized atoms are ionized by electron bombardment in the ionizer of a polarized ion
source which is being assembled.!)

The ionization process of atomic hydrogen (or deuterium)by electron bombardment is

Possible processes in which unpolarized background ions are produced from molecular hydrogenremaining in the ionizer are
H2 + e--+H2 + + 2e - ,H2 + e--+H+ + H + 2e - .

The first process producing a molecular ion beam is important only in a case that accelerationof ion is made without analyzing the atomic mass.

The unpolarized ions which are produced in

the second process cannot be removed in the accelerator.
One of the other constituents of the residual gas is water vapor.

Keller2) has shown thatthe effective cross section for producing protons from water vapor by 80 e V electrons is 40
times as large as that from molecular hydrogen.

However , the vapor pressure of water at

5-100° C is about 10- Torr and decreases by a factor of about ten per 10° C

decrease of

temperature~) Therefore use of the liquid nitrogen traps will be very effective to suppress thissource of the background.
( I ) Analysis of the residual gases
The amount of the residual gases such as the molecular hydrogen (H 2) and water vapor
Ion P um p(500 f/sec)~/

So l eno id Co il

Ion P ump
(12 5 f/sec )Oi l D ifu s ion
Pump (SOO r/se e )a nd Liquid N2 Trap

Fig. 1. Block diagram of experimental arrangement.

90(H 2 0) in the ionizer was measured using a quadrupole mass filter.

arrangement for measurement is shown in Fig. 1.

A block diagram of the

Evacuation of the vacuum chamber was

made by two diode sputter ion pumps of 125 and 500 t/s for N 2 • An oil diffusion pumpwith liquid N2 trap was also used to evacuate inert gases in the ionizer.

The amount ofoutgassing and leakage rate of the vacuum chamber was measured to be less than 2 X 10- 6
Torr. tis.
(2)

Structure of the ionizer

A tantalum filament was placed at one end of the ionizer and heated to about 2300°C by
direct current.

Electrons were drawn off the filament by the electrode E I .

Electrons travel

guided by the magnetic field produced by a solenoid coil along E I , E 2 , and are reflected at
the other end by negative potentials of E3 and E 4 .

All of these electrodes were washed withacetone and deionized water in an ultrasonic bath several times and dried in an oven at
80 - 150° C to clean their surface.

A typical set of operating parameters of the ionizer were

- - Befort' the operation'::, 6.0'

total pn'ssure : 1.8 X IO- ' T o J"r. ''>(-;'" 5.0------ - IJlIring the operation
total pr"sslIre: 9.0 X lO - ' T orr,~

Operating paramt'tf'r~ 4.0

F il : 30.-\ '< 4.1\'

r: 1 : O. 88k\' 87m.\
J':~ : 0 .62k\· 6Im ;\/. 3.0 t'"'
2 .0 ·I
I
I

1. 0 ': 28 :\ '} and CO
t

I

I
t

I

o[

Ii

t

C1 1.j 116 ::-\ 8 1 J hO
-

~ ~
Ii

It

32 0 ,
-

-~ :

40\,

44

C()~

t

--'-''--:'Ilass s p..,ct rum

Fig. 2. Mass spectrum of residual gases.
as follows:(E I ):

Magnetic field of solenoid coil:

1200 gauss, Filament current:

0.88 kV, 87 rnA, Ionization column (E 2 ):(3)

30 A, Extractor

0.62 kV, 61 rnA.

Results of observation of the residual gases during operation of the ionizer

Figure 2 shows the variation of mass spectrum of the residual gases in the ionizer before
and during operation.

The total pressure increased suddenly to 9 X 10- 7 Torr from 1.7 X 10- 7

Torr when we started the operation of the ionizer.

Each peaks of the residual gases was

identified with the cracking pattern coefficient4) and the partial pressure was given with relative
sensitivity to that of the nitrogen gas. s ) The observed residual gases were hydrogen, water vapor,nitrogen, carbon monoxide, oxygen, carbon dioxide, and argon before the operation of theionizer.

Under these conditions, each partial pressure was less than 10-8 Torr.

On the other hand, the partial pressure for H2 was greatly enhanced when the ionizer was
operated.

The partial pressure of H2 was 7 X 10- 7 Torr. 76 % of the total pressure.

91

Tot a l pr ess ure'-'- - - --0°",,,,,,,,,,0- ______ ..()- __--0 _ _ _ _ 0

N2 a nd CO- -0 - - -I,,,,'"_ _ _ -0 - _ _ _ _ _ _ 0'"

0- ______ -0 - - - - _---0

J'"

0,

d

----H 20
p'-'

'" '"

",,,,,,, '" '" "'/ - ______ ~------- ..()------- -o/ 0 '"

C02",/'"'" '" '" '" '"o---~(..--~

///

f "

I""

0 '"

I p_
II I I"" ....

---~'--0-___

0__------O----0_-------0

Ar

____

" o____ ===:~

1;/

/'

02 -- ___

I

I~

II

II

II

cf/ , 7 . 2X l 0- 10/'

Sta rting t i me

°
o

15

30

45

60

Opera ting t ime ( min )Fig. 3. Change of the partial pressure with operating time ofionizer.
Figure 3 shows the change of the partial pressure of residual gases with the operation timeof the ionizer. The partial pressures of H2 and N2 decreased slightly during the operation. It
seems that the partial pressure of H2 0 increases slowly during the operation because of thegradual rise of temperature of wall of the ionization region and the electrodes.
(4) Future improvement
If an atomic beam with an intensity of the order of 1015 atoms/cm 2 s at a velocity of

2.5 X 105 cmls (at T = 400 K) enters the ionizer, the equivalent beam pressure is about 10- 7
Torr. Therefore it is desirable to reduce the partial pressure of residual gas to less than ar (crosssection for residual gas) laa (cross section for atoms) times the equivalent atomic beam pressure.
The required improvements are given belowa)A liquid nitrogen trap has to be placed near the ionization region.

b)

The wall of vacuum envelope adjacent to the ionization region must be cooled bya suitable coolant.
c)

The inner wall of the steel vacuum envelope of the ionizer should be polished andelectroplated with tin.

92

After making these improvements one can expect that the partial pressures of hydrogenmolecule and water vapor in the ionization vacuum chamber are suppressed considerably.

References

1)

S. Motonaga, T. Fujisawa, M. Hemmi, H. Takebe, K. Ikegami, and Y. Yamazaki: IPCR
Cyclotron Progr. Rep., ~, 84 (1974).

2)

R. Keller, L. Dick, and M. Fiedecaro:

Report CERN 60 - 2 (1960).

3)

H. Kumagai, G. Tominaga, Y. Tsuji, and G. Honkoshi:"Vacuum Science and Engineering",

Shokabo, Tokyo, p.299 (1970).
4)

T. Hayashi and S. Komiya:"Ultrahigh Vacuum", Vol. 6, Vacuum Technology, Nikkankogyo,

Tokyo, p. 92 (1964).
5)

G. Tominaga: J. Vacuum Soc. Japan, ~, 19 (1955); 1, 27 (1955).

93

6-3.

Meehan ical Design of a

Polarized
for theIon Source

INS eye lotron

I. Takeshita

Details of the mechanical design of a polarized ion source , which is to be installed in thecyclotron, are described in the present article.

The fabrication of the source is now under way.

A simplified layout of the source is shown in Fig. 1.

The height of the source was limited to beless than 2 m, because of the available vertical space.
Figure 2 shows a schematic drawing of the IPCR polarized ion source.

Basic design of thesource followed that of TEXAS A & M University , which is characterized in the dissociation athigh pressure of 2 Torr.

The source consists of four vacuum chambers of stainless steel , three of,I

2C1: D F L.

.......
•(j • • '

'0

o

, ,0

' . '. c:. '. ~~ CYCLOTRONVAU LTC YCLOTROK.
. l'!I

r').
,,'

10

r~

I
I

I
I

1ST F I ..

I

I

I~

"

L'G

FI~ ,

,,
....

0

c

"

(;,

Fig. 1. Simplifi ed layout of the ion source.

' "~\'~'' '94

DIS SOCI ATOR
( WATE R COOLED )OIL DI F FUS I ON PUM P(2500 f'/ S ) ·2

SEXTUPOLE
MAG:-.JET

OI L DI FFUS ION PUMP

I~ I

12000f'/ S ) · 2

RF T RANSITIO\"UNIT

STRONG F I ELD
ION I ZERORR ITRON
101\ PUMP

LI QUID NITROGEN

THAP

FOCUS LENSUN IT

ION PUMP- -

-

-+-

-

-t--

9="-

Fig. 2. Schematic drawing of the IPCR polarized ion
source.
which are evacuated with five 2400 P/s oil diffusion pumps and the other is pumped with aorbitron ion pump of 1000 Pis.
dissociation chamber to 3 X 10-

In the vacuum system, the pressure varies from 2 Torr in the7Torr in the ionization vacuum chamber.

Some notable designs were done in the mechanical design of the ionizer in order to fulfill
the following specifications.

A sectional view of the strong field ionizer is shown in Fig. 3.

The strong field ionizer is placed in the ionization vacuum chamber, which is a cubiform of 36 cm
in width, 40 cm in length and 48 cm in height.
to the atomic beam.

A solenoid produces a magnetic field parallel

An electron gun is placed at one end of the ionization area and extraction

electrodes which have negative potential are placed at the other end. The electrons makecirculating motion in the ionization area before collision.

95

THE LID IS DESI G:-lED
TO BE LEMOVED/~/ THE LEADTHROUGH

,-

/

I

1.

Filament (Ta);2.

Grid, El (Ta);3.

Ionization column, E2 (Ta) ,4. } Extraction electrodes, E3 , E4 (eu);'- THE SOLE:\OIDECO IL CASING

5.

6.

Grided electrode, Es (stainless steelwire).

Rig. 3. A sectional view of the strong field
ionizer.
LIQUID NITROGEN TRAP

THE SID E LID OF
THE \· ACUU ~I C HA~IB EH

Fig. 4. A drawing of one of the electriclead throughs.

96

The solenoid casing and all of the leadthroughs are mounted on the side lid of the vacuum
chamber.

The lid was designed to be removed easily for exchange of the filament or for

re-alignmen t of the electrodes and magnetic field.
In order to inject an ion beam to the injection system with maximum energy of 20 keY,
the solenoid coil, the filament, and all of the electrodes are biased at a positive potential of
20 ke V to the ground.

The ionizer vacuum chamber is at the ground potential.

Therefore,

the solenoid coil casing and all of the electric and cooling leadthroughs must be insulated
electrically from the vacuum chamber.

The solenoid casing is mounted on the side lid of thevacuum chamber with four glass insulators.
shown in Fig. 4.

A drawing of one of the electric leadthroughs is

This leadthrough is used to supply an electric current of 150 A to the solenoid

and feed Freon coolant simultaneously under 20 keY electric potential to the ground.
glass insulator is used because it can be manufactured easily.

An epoxy

Before attaching the lead through tothe vacuum chamber the insulation of the lead through was tested under vacuum up to 20 keY
without any trouble.
As shown in Fig. 3 or 4 a compact helical solenoid coil was made by stacking annularplates of copper of 1 mm in thickness, 130 mm in outer diameter, and 66 mm in inner diameter.
Electric current density is 4.7 A/mm 2 at 150 A maximum current and the maximum heatdissipation of 1.2 kW is removed with Freon coolant.
A particular attention was paid for keeping high vacuum in the ionization chamber.

Thus

the surface of the solenoid coil casing, which is exposed in the vacuum, was polished byelectrolysis, and the inner surface of the vacuum chamber was polished by using high pressur;..
blast of glass beads.

97

7. A TOMIC AND SOLID-STATE PHYSICS

7-1.

Inner-Shell Excitation

by Nitrogen

Ions and A Ipha Particles (3)Y. Awaya, K. 1zumo, T. Hamada, M. Okano,
A. Hashizume, T. Takahashi, Y. Tendow, and T. Katou
Recently, some experimental studies have shown the deviation from the Z l 2 - dependence
in the K-shell ionization cross section l ) - 5) where Zl is the atomic number of the incident particle.
The plane wave Born approximation predicts that R2K ==unity, where thenumber Z2.

o2K (Zl)(Z.')/Zt'2 ] /[02K (ZI)/Z I2] equals[o2K

is the K-shell ionization cross section of the target atom of atomic

The cause of this deviation would be twofold, i.e. increased binding energy of target

electrons (prevailing for VI < V2K) and the polarization of them (prevailing for VI:< v2K)'

where, v I and v2K (== Z2e2/h) are the velocity of projectile and that of K-electron of target
atom, respectively.

These two processes have Z l 3 -dependence and their contributions to thecross section are in the opposite direction. They cancel each other at V1 /V2K = ()K/2, that is,
R2K = I, where ()K == 21 2K /Z 22, and 12K (in a.u.) is the ionization energy of K-sheU.t)
We measured the X-rays from the target atoms induced by 5 MeV/amu N-ions anda-particles.

The target atoms ranged from Cr to Bi and the preliminary results of the work werereported previously .6) , 7)

We reanalyzed the ratio of the K X-ray yields of N-ion and a-particle

bombardment to study the deviation from the Z l 2 -dependence.

1.5

0

~
ct:

(0)

0

1.0

(0)

0

(0)

f
0.5

0

0

I

• Pres ent datao Ref . 2~4
0.5cr( He)At target 4cr(H)Ref.2

Ni targetcr(U 19cr(D )• Ref. 2

AC target

9cr(D)(0)

1.0

4cr(N)
49cr(He)

1.5

cr ( Li )

2.0

t;K

Fig. l. Ratios R2K of K-shell ionization cross sections as a function of ~K·

98

In order to obtain a universal curve, values of R2K were plotted as a function of ~K'
where ~K == vl/(()Kv2K/2), since R2K becomes unity at ~K=

1 as described above.

In ourexperiment VI is constant whereas Z2'S take values of 24 to 83; on the other hand, single
element was bombarded with projectiles of different velocities in the literature cited. l )- 4)
The result is shown in Fig. 1 together with the data obtained by Basbas et a1. 2); the tendencyof the deviation from the Z l 2 dependence is similar.
the projectile and target combination.
~K

The amount of the deviation depends on

It seems that some universality holds between R2K andand this result shows that the main mechanism for K-shell ionization under the present

experimental conditions is the direct Coulomb excitation.

References
1)

G. Basbas, W. Brandt, and R. Laubert:

2)

G. Basbas, W. Brandt, R. Laubert A. Ratkowski , and A. Schwarzschild: Phys. Rev. Lett.

Phys. Lett., 34A, 277 (1971).

27 , 171 (1971).
3)

C. W. Lewis, 1. B. Natowitz, and R. L. Watson: ibid. , 26, 481 (1971); Phys. Rev., A, 5,
1773 (1972).

4)

G. Basbas, W. Brandt, and R. Laubert:

5)

N. Cue, V. Dutkeiwicz, P. Sen, and H. Bakhu:

6)

Y. Awaya, T. Hamada, M. Okano , A. Hashizume, T. Takahashi, K. Izumo, Y. Tendow,
and K. Katou:

7)

ibid., ,] , 983 (1973).
Phys. Rev. Lett. , 32, 1155 (1974).

IPCR Cyclotron Progr. Rep. , 2, 87 (1973).

K. Izumo, Y. Tendow, Y. Awaya, T. Katou , M. Okano, A. Hashizume, T. Takahashi, andT. Hamada:ibid. , p. 93.

99

7-2.

Positron Annihilation In V and Nb

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

Systematic studies of the electronic structures of transition metals by measuring the angular
distribution of the positron annihilation radiation are in progress.
After completion of the experimental studies on V and Nb , a detailed theoretical calculation
employing APW method has been made by Wakoh et al. l )The (100) experimental angular

distribution curve for Nb is shown in Fig. I together with the theoretical curve as an example.
The agreement is fairly good and the fine structures in the experimental curve are identified as
the corresponding ones on the theoretical curve.

Anisotropies of the experimental angular

distribution curves, i.e ., the differences between the curves along three major crystallographic
directions, are shown in Fig. 2 together with the theoretical ones calculated by Wakoh et al.

T heo r' eti ca l angulnr di s tr i hu t i on h,\ ' \\' ak oh

f'i (//.

:\' b ( 100 )- ---Total- - - , - 1s t ha nd- - - - -- -2nd hand- - - - - - - - - - 3 r rl ha nrl-- - Cor eCI.

c- --, - - - --

o

1,0

0,5

1.5

I<\p,

2,0

l' )oIll Pn tu lll i n .-\. l ' ,Fig. 1. Experimental angular distribution in Nb
together with the theoretical ones withindividual contributions from the core states,
the first , second, and the third bands takenfrom Ref. 1.

100- - - Exper im e nt

- - - ExperimentNbV--- - - -- Theory
by Wakoh e l al.

--------- T heo r y
by Wakoh el al.

( 110 )- (100 )(1 10 ) - ( 100 )o ~+-------~--~~~--~~---(111 ) - (100 )(111 ) - ( 110 )(111 ) - ( 110 )Momentum in A.U.

in A.U.

Fig. 2. Experimental anisotropy curves and theoretical ones calculated by Wakoh
et al. for V and Nb.

The agreement is fairly good for V and excellent for Nb.
These comparisons between experiments and theory have established the validity of the
one-electron approximation of the band electrons in transition metals on the one hand, andrevealed the limitation of the applicability of the independent particle model to this problem on
the other hand.
A detailed report will be published elsewhere. 2 )References
1)

S. Wakoh, Y. Kubo, and J. Yamashita: J. Phys. Soc. Japan, 38,416 (1975).

2)

N. Shiotani, T. Okada, T. Mizoguchi, and H. Sekizawa:ibid., p. 423.

101

7-3.

A

Damage Function Based on the Focused
Replacement Collision Model

H. Sakairi, E. Yagi, A. Koyama, and R. R. Hasigu ti

A damage function v (Ep) represents the average number of displaced atoms created bya collision cascade initiated by a primary knocked-on atom with an energy Ep.

A simple

expression of it was given by Kinchin and Pease ) and the refined one by Snyder and Neufeld. 2 )lResults of calculation with these expressions, however, give a larger number of displaced atoms
than the experimental values by a factor of 4 - 5. 3 ),4) The discrepancy is probably due to thefocused replacement collision sequences being neglected in the basic assumption.

It is an effectof the periodicity of crystal structure, which was predicted theoreticallys) and revealed by
a computer simulation. 6 )As reported previously, 7) the defect production rate in Cu and ordered alloy CU3Au
irradiated below 10K with charged particles from the cyclotron shows that the number of
atomic replacements is in proportion to the number of atomic displacements, suggesting that
almost all displacements occur as a result of replacements.

Therefore the damage function wasreconsidered according to the focused replacement model as follows.
The basic equation is the same as used by Snyder and Neufeld, that is,lI(E p)

\ Ep

dE 2

\ Ep- Ed

dE 2

(1)

= J~(E2) Ep + J lIo(E p -E2 - E p ) Ep

The first integral in the right-hand side is the average number of displaced atoms in thecollision cascade initiated by the primary knocked-on atom whose energy was reduced from Ep
to E2 by the first scattering.

The second integral is that created by the secondary knocked-on

atom produced by that scattering.

Here Ed is the threshold energy for displacements and dE 2 /E p

is the probability of finding the scattered atom with energy in dE 2 at E 2 , given by the hard
sphere approximation.
Boundary conditions were taken asforEp < Ed,(2a)

Ed s Ep:S:EF'(2b)where Ep is the focusing energy.
Equation I was integrated analytically to v (Ep) = In (Ep/Ep) for Ep between Ep andEp + Ed, and numerically above Ep + Ed'
in Pig. 1.

An example of the results of calculation is given

The tangent of the asymptotic linear line is given by aEp-~, where a and f3 arefunctions of Ed as shown in Pig. 2.

This expression holds in the energy region where elastic

collisions dominate electronic excitations, above which the expression must be given in sucha modification as proposed by Kinchin and Pease.

102

3 ,0 , - - - - - - -- ---------------,

1. 0,----- -- - - , - - - - - - -----,---- - ---,

2 ,0
~: I

0,5 1-- ---"<-- + - - -- ---+---------1

j
1. 0

Ed = 30e\ '

o

200

100

0,2 1-----+-------~-+---------l

0 , 11'0 -- -- 2.'-:--0-------=5.'-:--0-300------:--:100

Ep \e\ ' )Fig. 2. a and ~ as functions of Ed·

Fig. 1. An example of vCEp) curve calculated
for EF = 100 eV and Ed = 30 eV.

Snyder and Neufeld took a boundary condition,

instead of (2b) and obtained 0.56 E d -1 as the tangent of the asymptotic line.

Thompsonintuitively proposed to replace Ed simply by EF for including the focused replacement sequences
into the mode1. 8 )This is shown, however, to be incorrect by the present calculation.

For Ed = 22 eV, which is accepted as the average threshold energy for displacement inCU,9) a is 0.37 and ~ is 0.83.

Then EF must be taken 135 eV to make up the difference

between the theory and experiments on the damage function by the contribution from focused
replacement chains only.

If the contribution from electronic excitations, which was neglectedin the present consideration , is assumed to be about 20 %,10) it decreases to about 100 eV.
These values are large compared with the theoretical values of EF for Cu obtained by thecomputer simulation C'" 40 e V). 6 )progress.

Another experiment to estimate the EF values is now in

It is also hoped that theoretical models for the calculation on focused replacement

collision sequences are reexamined.

ReferencesI)

G. H. Kinchin and R. S. Pease:Rep. Prog. Phys. , 18 , 1 (1955).

2)

W. S. Snyder and J . Neufeld:

3)

H. G. Cooper, J. S. Koehler, and J. W. Marx:

Phys. Rev., 97 , 1636 (1955).
ibid., p. 599 .

103

4)

D. K. Holmes:"Interaction of Radiation with Solids", ed. R. Strumane et al., (North

Holland Publishing, 1964) p. 147.
5)

R. H. Silsbee:

6)J. B. Gibson, A. N. Goland, M. Milgram, and G. H. Vineyard: Phys. Rev., 120, 1229

J. Appl. Phys., 28, 1246 (1957).

( 1960).
7)

H. Sakairi, E. Yagi, A. Koyama, T. Karasawa, and R. R. Hasiguti:

IPCR Cyclotron Progr.

Rep., 5, 101 (1971).
8)

M. W. Thompson:"Defects and Radiation Damage in Metals", (Cambridge Univ. Press,

1969) p. 241.
9)J. W. Corbett: "Electron Radiation Damage in Semiconductors and Metals", Solid State
Physics, ed. F. Seitz and D. Turnbull, SUppl. 2, (Academic Press, 1966) p. 240.

10)

G. Dearnaley, J. H. Freeman, R. S. Nelson, and J. Stephen:
Holland Publishing, 1973) p. 161.

"Ion Implantation", (North

104

7-4.

Secondary Electron Emission fromAI and Ni

by Fast-proton Bombardment

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

Secondary electron emission ratios 'Y were measured on A 1 and Ni for fast-protons (2 '" 10
Me V) from the cyclotron.

The specimens were mirror-polished and cleaned in an etanol-acetone

mixture with an ultrasonic cleaner.

T...

Collimated beam

Fig. 1. Target-collector system. T: target, C: collector,
S: secondary electron suppressor.

2.0
>--

.-......0

0 - - 0 Al

l.5

6--6. Ni

~

r-.
c

l.0
0.8
r.Il
0

r.Il

E
Cl)

c
0
r-.

......
u

0.6
0.4

Cl)
~

Cl)

>-,

r-.

~

'"0

c
0

u
Cl)

VJ

l.0

2.0

4.0

6.0

Proton energy

10.0 14.0( MeV )

Fig. 2. Dependence of secondary-electron emission
ratio on the incident proton energy.

105

Figure 1 shows the target-collector system used for the experiments.

Figure 2 shows theexperimental results on 'Y which fit the following formulas:

YAI =1.85E 1

YNi =1.62E 1- 0.75,and- 0.70'where EI (MeV) is the energy of incident protons.
Aarset et al. measured 'Y A I at the lower energies, below 2 Me V, 1) and the results can be
expressed by the next equation,

A theoretical expression for 'Y is generally given as

y=aE 1- (3'in which 0: is mainly related to the transport of the inner secondary electrons and the emission
from the metal surface, while ~ is to the mechanism of the direct excitation of metal electrons
by incident particles.

Therefore 0: is influenced by the surface conditions while ~ is not for

the high incident energy and the thin surface contaminant layer in these experiments.
According to the theoretical calculation by Ghosh et aI., who improved the one by
Sternglass,2) the energy dependence of 'Y was expressed as follows: 3 }YAl ~EI
Y Ni ~ E I- 0.90

,and

-0.80

There is an apparent discrepancy between the experimental and theoretical energy dependence.
Improved calculations are now in progress.

References
1)

B. Aarset, R. W. Cloud, and 1. G. Trump: 1. Appl. Phys., 25, 1365 (1954).

2)

E. 1. Sternglass:

3)

S. N. Ghosh and S. P. Khare:

ibid., 108, 1 (1957).
Phys. Rev., 125, 1254 (1962).

106

8. RADIOCHEMISTRY AND NUCLER CHEMISTRY

8-1.

Charged-Particle Activation Analysis

T. Nozaki, M. Iwamoto, Y. Yatsurugi, and N. Akiyama

After our previous report,!) we have applied charged -particle activation analysis to thefollowing four studies: (1) examination of reliability and accuracy in the calibration curve forthe infrared spectrophotometry of oxygen in semiconductor silicon, (2) search for effects ofimpurity carbon on electronic properties of semiconductor silicon, (3) investigation of therelationship between ambient carbon monoxide concentration and carbon and oxygen contents
of molten silicon in the single-crystal formation of semiconductor silicon, and (4) development of
convenient procedures for the determination of oxygen in various high-purity matrices byactivation with the 16 0 CHe, p) 18F reaction. In addition, the determination of surface
impurities by charged- particle activation analysis is under planning.

Some results for studies (1)and (2) have already been published. 2),3)
The equilibrium constant for the carbon monoxide concentration ([CO] in atm) and thecarbon and oxygen contents ([C] and [0] in wt ppm) can be calculated from the solubility ofcarbon and oxygen 1),2) and the free energy for the reaction of SiC + SiO = 2Si + CO. It is
obtained as:

K=[COJ =1.9 X IO - 7
LCJ [OJ

Preparing silicon crystals under various conditions and analyzing them, we examine the validityof this equation for the equilibrium condition and also deviations from it in non-equilibrium
states which are usually encountered in the practical single-crystal formation.
For reliable and sensitive determination of oxygen by the 16 0 CHe, p) 18F reaction, aconvenient technique for the chemical separation of the 18F involving sample decomposition
should be developed for each matrix.
methods:

We tested the usefulness of the following decomposition(1) dissolution in alkaline solutions, (2) oxidative dissolution in acids in a closed

system, and (3) electrochemical dissolution.

The 18F in the resultant solution has proved to bemade radiochemically pure by the following steps:(I) precipitation of PbFCI or coprecipitationof CaF 2 with CaC0 3 , (2) steam distillation of fluorine in the precipitate as H2 SiF 6, and (3)precipitation of benzidine flu oro silicate or LiF from the distillate.

Our final aim is to makea convenient manual for routine determination of oxygen in a variety of matrices.

107

References

IPCR Cyclotron Progr. Rep., §.' 106 (1972).

1)

T. Nozaki, Y. Yatsurugi, and N. Akiyama:

2)

Y. Yatsurugi, N. Akiyama, Y. Endo, and T. Nozaki: J. Electrochem. Soc., 120, 975 (1973).

3)

N. Akiyama, Y. Yatsurugi, Y. Endo, Z. Imayoshi, and T. Nozaki: Appl. Phys. Lett.,
22, 630 (1973).

108

8-2.

Mossbauer Emission Spectroscopy of

119

Sn

after the EC Decay of

119

Sb

F. Ambe and S. Ambe

Mossbauer emission studies of the electronic state in 119Sn after the Ee decay of 119Sb1)-s)have been extended further to various antimony and tellurium compounds labeled with 119Sb or
119m Te (parent of 119Sb).

A new series of experiments has also been started, in which tin

compounds irradiated with charged particles were analyzed as the Mossbauer source.
The data accumulated so far on 119Sn in the Sn-Sb-Te system have led to a systematics of
As is seen in Table I, the isomer shift of the 119Sn atoms increases with an

the isomer shift.

increase in the electronegativity of the nearest neighboring atoms independently of the structureof the matrix.

This is also true even if they are tin atoms in a defect state.

In case of thesources labeled with 119mTe, one cannot be certain a priori whether or not the 119Sn atoms
produced by successive Ee decays of 119mTe via 119Sb occupy the original site of 119m Te, since
the recoil energy accompanying the Ee decay of 119mTe to 119Sb is estimated to be of the sameorder of magnitude as the displacement energy in solid.

However, if the dominant emission

lines observed for Sn 119m Te 9.nd Sb 2 119m Te 3 are assumed to represent the 119Sn atoms in theoriginal site of 119mTe, their isomer shifts fit very well the systematics as shown in Table 1.
The systematics derived above was utilized in its tum to determine the lattice position of
the 119Sb atoms produced by proton reactions on tin in SnSb and SnTe.
Table

1.

Powder samples of

The isomer shifts of defect and normal 119Sn in Sn-Sb-Te system.
Nearest Neighborof 119 Sn

Isomer
Shift a )Matrix

MethodSn 119m Te
Sn l19 Sbemission

S11

2.26 b )emission

S11

2.43

Sb2119mTe3

emissionSb

2.30 b )119Sb metal

emission

Sb

2.66

SnSb

absorption

Sb

2.79

119mTe metal

emissionTe

3.00

119Sb2 Te 3

emission

Te

3.37

SnTe

absorption

Te

3.54

a) mm/s v s , BaSn03 at 78 K.
b) The value refers to the dominant line.

109

100

(a)

90
:>.
<.n

c

'"c

'"> 100
'"
'"
a:::

008'

+-

%
0°&

0 0

(bl

98

o

-4
Relativeve locity

8

4(mm /sec

vs

BaSn03

at

78 K)

Fig. 1. Mossbauer (a) emission and (b) absorption spectra of
p-irradiated SnSb at liquid nitrogen te!11perature.

:>.

92

<.n

c

......
'"c:

'">
a:::
'"

96

o

-4
Relative

velocity

84(mm /secvS BaSn03 at

78K)

Fig. 2. Mossbauer (a) emission and (b) absorption spectra of
p-irradiated SnTe at liquid nitrogen temperature.

110

SnSb and SnTe were irradiated with 16-MeV protons in a helium atmosphere. Since tin metalenriched in 120Sn 20Sn 98.39 %, 119Sn 0.39 %) was used for preparation of the samples ineorder to minimize the resonant self-absorption of the 23.8 keY Mossbauer r-rays in the sources,
the main nuclear reaction leading to 119Sb must have been the 120Sn (p, 2n) 119Sb reaction.

The

Mossbauer emission and absorption spectra of the irradiated samples were measured at liquid
nitrogen temperature.

The standard absorber and source used in each measurement were BaSn03

and Ba 119m Sn03 respectively.
Typical spectra obtained are shown in Figs. 1 and 2.

The emission spectra (1 (a) and 2 (a))

represent the electronic state of 119Sn in the Mossbauer level after the EC decay of 119Sb
produced by the proton reactions, while the absorption spectra (1 (b) and 2 (b)) show theradiation effect of the protons on the matrices.
As is seen in Fig. 1 (a), the SnSb irradiated with protons gave an emission line with anisomer shift of 2.4 mm/s.

From the systematics shown in Table 1, this line is attributed to

the 119Sn atoms replacing the Sb-site of SnSb.

The emission spectra of p-irradiated SnTe werecomposed of two lines with isomer shifts of 2.3 and 3.5 mm/s, which can be assigned
similarly to the 119Sn in the Te - and Sn-sites respectively (Fig. 2 (a)).

As the recoil energy

associated with the EC decay of 119Sb to 119Sn is not large enough to displace an atom in solid,
the lattice positions of 119Sn determined from the emission spectra are considered to represent 'simultaneously those of the preceding 119Sb recoiled by the proton reactions.

Therefore,

the following conclusion can be drawn from the assignment described above:

In case of SnSb

all the recoil 119Sb atoms produced by the proton reactions were stabilized in the Sb-site, while
in SnTe the 119Sb atoms were distributed among the Sn- and Te-sites.

These observations showthat the final lattice positions of the recoil 119Sb atoms in the matrices are determined in the
repairing process of the disordered lattice near the end of the recoil track.

The absorption

spectra of the irradiated SnSb and SnTe (Figs. I (b) and 2 (b)) revealed no significant difference
from those of the unirradiated samples.

This means that the radiation effect of protons on thematrices was less than the detection limit of the measurement.

References
1)

F. Ambe, H. Shoji, S. Ambe, M. Takeda, and N. Saito: Chern. Phys. Lett., 14, 522 (1972).

2)

S. Ambe, F. Ambe, and N. Saito:

3)

F. Ambe and S. Ambe:

4)

F. Ambe, S. Ambe, and H. Shoji:

5)

F. Ambe, S. Ambe, H. Shoji, and N. Saito:

6)

F. Ambe and S. Ambe:

Bull. Chern. Soc. Japan, 47, 2875 (1974).

7)

S. Ambe and F. Ambe:

Radiochim. Acta, (in press).

8)

S. Ambe and F. Ambe:

Inorg. Nucl. Chern. Lett., 11, 139 (1975).

Radiochim. Acta, 19, 121 (1973).

Phys. Lett., 43A, 399 (1973).
Radiochem. Radioanal. Lett., 15, 349 (1973).
J. Chern. Phys., 60, 3773 (1974).

III

8-3.

Behavior of Tritium and Hydrogen Atoms on Metal Surface

M. Aratani

The behavior of tritium and hydrogen atoms mainly on titanium surface has been studied
by means of a charge spectrometer, the details of which being previously reported 1 ),2).

Tritium

atoms were fixed on the surface of a titanium plate (10 mm X 15 mm) in the form of titanium
hydride.

This was used as a beta-ray source and as an ion source of the spectrometer.

effective radioactivity was 96 mCi.

The

Counting rates of various ions were measured at pressuresfrom 6 X 10- 5 to 2 X 10- 7 Torr for 1 H2 and 4He gases.

In the present ex perimen t, 1 H2 and

4He were used instead of 3H 2 and 3He, decay product of tritium, for the reason that use oftritium-containing gases in a metal chamber resulted in a "sticky" adsorption on the inside wallof the chamber,3),4) and an isotope effect did not affect adsorption and ionization.
As a result of measurement, it was revealed that there appear i) ground-state ions of heliumat above 3 X 10- 6 Torr, ii) metastable ions of helium at above 6 X 10- 6 Torr, iii) ground-stateions of hydrogen molecules at above 1.8 X 10- 6 Torr, iv) metastable ions of atomic hydrogenat above 3.6 X 10- 6 Torr, and v) ground-state ions of atomic hydrogen in every run in thepressure range examined.

Pressure dependence of the counting rates of the ions from i) to iv)

is given by a linear expression, which is reasonably interpreted in terms of Henry-type adsorption
and ionization of the adsorbed neutral species on the surface.

The discussion will be publishedelsewhere. s )On the other hand, the ions described in v) show entirely different behavior from theothers.

Pressure dependence of the ion counting rate is given by a cubic root expression.

Threshold pressure does not appear in the pressure range examined.

Extrapolation by the cubicroot expression gives a threshold value of 10- 9 Torr.

This small value suggests that the ions arederived from the very "sticky" species on the surface.

The cubic root expression implies thatthe species contains three atoms of hydrogen, for example, H 3, H 3C, H 30, and so on.

Helium,the decay product of tritium, is not "sticky" at any pressure below 3 X 10- 6 Torr as decribedin i) and ii).
One of the most practical conclusions to be emphasized here is that hydrogen as well as
tritium should be used in the pressure range below 10- 9 Torr or in a solid form in order toavoid the "sticky" adsorption.
References
IPCR Cyclotron Progr. Rep., :!' 117 (1970).

1)

M. Aratani, M. Inarida, and N. Saito:

2)

Y. Kawana and M. Aratani: In1. J. Mass Spectrometry Ion Phys., 10, 493 (1972/73).

3)

A. Shimamura, M. Tonuma, 1. Sakamoto, and 1. Kohno: Reports I.P.C.R., (in Japanese)

1 1248, 69 (1972).
4)

T. Shiokawa: Private communication.

5)

M. Suehiro, M. Aratani, and N. Saito: Mass Spectroscopy (in press).

113

8-4.

Mass Asymmetry In the Fission of Actinide Nuclei

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

For the five isotopes of Th, Pu, em, Fm, and No and eight isotopes of U, the contour
maps of the constant total potential energy were plotted as a function of the center separation

Zo and the fragment deformations O. The calculation was performed based on Strutinsky's
prescription, 1) in which the liquid-drop model of von Groote and Hilf2) and the modified
two-center harmonic oscillator shell model were used for the macroscopic and microscopic parts,
respectively.
The results of these systematic calculations of the actinide nuclei are collected in Table 1,
in which the positions of the ground state, first saddle, second minimum, and the second saddle
are shown.
Also are shown the ground state energy (E Gs ) relative to the spherical liquid-drop modelenergy and heights of the first saddle (E BI)' the second minimum (E II) and the second saddle(E BII) relative to the ground state.
The discussion about these results by comparing with those of Moller and Nix 4 ) will begiven elsewhere and the present discussion is restricted to the mass asymmetry.
(1)

Mass asymmetry and importance of some level pairs

In order to investigate the origin of mass asymmetry, in Fig. 1 the single particle level
diagram at the second saddle is shown as a function of the fragment mass ratio.

These arethe neutron levels of 236U because the neutrons are more responsible for the asymmetry thanprotons.
From Fig. 1 some pairs of levels with quantum numbers of (N 0 A) and (N + 1 1 A), forinstance, pairs of ([615] 11/2+, [505] 11/2-), ([512] 3/2-, [402] 3/2+), ([512] 5/2-, [402]5/2+), etc, can be found near the Fermi level.

As was already pointed out in Refs. 5 and 6,

these level pairs play an important role in directing the fission to an asymmetric path.
spacings of these levels are small at the symmetric deformation.

The

The reason is that they begin

to degenerate as Z 0 becomes large in the case of symmetric deformation and that the degeneracy
occurs at an early stage of fission as they have small n z'
the relation,~N=l,~nz=l,* Japan Atomic Energy Research Institute.
** Osaka City University.

~A= 0,The level pairs are connected with

114

236 U

e ut r on levels

zo= 8.5fm

8 = 0.31

631 32 r
743 712 -752 312
1750+ 761 1 12

118/ 118( l. 0 )128/ 108( l. 185 )

138/ 98( 1. 408 )

148/ 88
0. 682 )158/ 78(2. 026 )MH / ML

Fig. 1. The neutron single-particle level diagram of 236 U calculated
at the second saddle point (Zo = 8.5 fm and D = 0.31) forsymmetric fragmentation as a function of the mass ratioof the fragments. Each energy level is labelled by theasymptotic quantum number of Nilsson (Nn z 1\)[2 1T which
is defined here as that of the main component of the wave
function at the second saddle point for the symmetricfragmentation.

so that they have a large matrix element for the octupole deformation.

Therefore they repel

each other when the potential deforms asymmetrically and then level spacings between them
become large.
The most apparent example of this phenomenon can be seen in the pair ([ 615] 11/2+,[505] 11/2-).

As a result, there occurs a rather large energy gap between neutron number 142

and 144 at MH/ ML ;.::: 144/92.

This energy gap causes the asymmetric fragmentation.

It should be noted that the single particle levels as a function of mass ratio based on the115

Table 1. The calculated locations and energies of the ground state, first saddle, second
minimum, and second saddle.

All energies are in unit of Me V and Zo are in unit of fm.

At

the second saddle, the most favorable masses of heavy fragments, M H, and those of lightfragments, M L, are also shown.

For the nuclei with asterisk, the contour maps of the collective

potential energies are very irregular and in particular the locations of the second saddle are very
ambiguous.

So the mass ratios of these nuclei have little reliance.

by the visual interpolation from the contour maps.

The locations were determined

The errors due to the procedure are about± 0.2 fm for center separation Zo and ± 0.02 for deformation {j.

Second minimum

Second saddle,.---A-----,~~--------~------------\

Zo

8

Zo

8

Ell

Zo

8

0.0
0.0
0.0
0.0
0.0

0.18 1.3
0.20 0.3
0.20 - 0.5
0.20 - 0.5
0.19 0.1

2.7
2.7
2.5
2.5
2.5

0.20 2.3
0.25 4.2
0 .27 5.0
0.28 5.5
0.29 5.4

4.5
4.5
5.0
5.6
5.5

0.30
0.30
0.30
0.23
0.56

1.0
1.8
3.0
3.6
3.4

9.0
9 .0
9.0
9.8
13.0

0.35 7.3
0.32 7.1
0.30 8.4
0.21 9.1
0.1111.1

0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0

0.19 1.2
0.20 0.8
0.20 0.2
0 .20 - 0.3
0.20 -0.7
0 .20 - 1.0
0.20 - 1.0
0.20 - 0.3

3.5
3.5
3.2
3.5
2.8
2.5
2.4
2.5

0.23
0.20
0. 23
0 .20
0. 25
0.26
0.27
0.28

1.8
2.7
3.2
4.8
5.2
5.8
6.0
5.4

4.7
4.5
4.5
4.5
4.5
5.7
5.9
5.8

0.29
0.30
0.30
0.30
0.30
0.21
0.21
0.26

0.3
0.7
1.3
1.8
2.2
2.7
3.3
3.4

23~142

0.0

0.21

0.1

3.1

0.23 3.4

4.8240pu146

0.0
0.0
0 .0
0.0

0.20 - 0.9
0.20 - 1.7
0.21 - 1.6
0 .21 - 0.9

2.9
2.5
2.5
2.5

0 .24
0.26
0 .27
0 .28

5.4
6 .2
6.1
5.7

4.7
6.0
6.2
6.0

0.0
0 .0
0.0
0.0
0.0

0.20 - 0.6
0.20 - 1.7
0.20 - 2.3
0.20 - 2.3
0.20 - 1.7

3.0
2.8
2.5
2.4
2.5

0.24
0.24
0.26
0 .27
0 .27

3.7
5.6
6 .6
6.9
6.4

0.0
0.0
0 .0
0.0
0.0
0.0

0.21 - 1.3
0.21 - 2.2
0.21 -2.9
0.20 -2.9
0.21 -2.9
0.21 -2.9

3.0
2.7
2.5
2.5
2.4
2.5

0.24
0 .25
0.26
0.27
0 .27
0.30

0.0
0.0
0 .0
0.0
0.0

0.21 - 1.9
0.21 -2.8
0.20 -3.4
0.20 - 3.4
0.19-2.8

2.8
2.6
2.5
2.5
2.4

0.0
0.0
0.0
0.0
0.0

0.21 - 2.2
0.20 - 3.1
0.20 -3.7
0.20 - 3.7
0.20 -3.5

2.8
2.7
2.5
0.5
2.5

Ground state

23~ThI42
23&rh l46

~h150

~h154
24B-rh 1S8~2UI40234 U 142

236UI44
238U 146
240U 148
242U150
246U154
250UI58

244Pu150
248Pu154
252pU 158~~CmI42
242Cml46
246Cm150
250Cm154
2S4Cm158~~CfI42
244Cf146
248Cf150
250Cf152
252Cfl54
256Cf 158

r~Fm142
246Fm146
250Fm150
2S4FmlS4
258Fml58

roiNo 142
248No146
252No150
256No154~0158

First saddle

ML

MH/ML

147
148
147
146
129

85
88
93
98
119*

1.729
1.681
1.580
1.489
1.084

8.2
8.5
8.5

0.35 4.3 147
0.35 5.1 148
0.31 5.3 146

85
86
90

8.8
8.9
8.8
9 .0
11.1

0.32
0.30
0.30
0.31
0 .08

6 .2
6.7
7.3
7.2
8.7

148
147
147
149
130

90
93
95
97
120*

1.729
1.720
1.622
1.644
1.580
1.547
1.536
1.083

0.30 0 .5

8.0

0 .35 3A

146

90

0.30 1.5
0.20 2.3
0.21 3.0
0 .26 3.0

8.5
9.0
10.0
12 .0

0.30
0.25
0 .15
0 .00

4.8
6.6
7.8
6.2

145
145
136
129

95
99
112*
123*

4.8
4.8
6.1
6.3
6.9

0.36
0.30
0.21
0.22
0.19

0.5
1.4
2.0
2.7
2.6

7.6
8.3
8.6
9 .6
9 .2

0 .36
0.29
0 .28
0.16
0.04

2.0
3.8
5.0
6 .7
3A

145
144
145
138
127

93
98
101
112*
127*

1.559

3.8
5.7
6.7
6.6
7.0
6.8

5.0
5.0
6.4
8.2
9.1
9.3

0.30
0.31
0.20
0.12
0.00
0.00

0.1
0.9
1.6
1.5
1.6
0 .6

7.5
8.3
10.0

0.8 144 96
2.0 14599
4.3 130 118*
3.9 132 118*
3A 130 122*

1.500

10.8

0 .35
0.31
0.10
0.05
0 .00

0.25
0.25
0.26
0.27
0.27

4.2
5.8
6.8
7.1
6.6

5.3
5.1
6.5
8.1

0.31 - 0.4
0.31 0.3
0.21 1.1
0 .12 1.3

6 .6
6.5
9.5
9 .5

0 .41 - 0.3 141 101
OA3 1.9 146 100
0.03 2.G 128 122*
0 .05 1A 128 126*

1.396
1.460
1.049
1.015

0 .25
0.25
0.27
0.37
0.27

3.7
5.6
6.6
6.6
7.0

5.7
5.4

0.33 - 1.6
0.33 -0.4

6.4

OAO - 2.2

6.6

OA2 - OA

139
144

105
104

1.323
1.384

6.7
7.3

0 .22 0.2
0.20 0 .2

8.7
9 .8

0 .25 1.0
0.09 0.8

143
131

109
125*

1.311
1.048

EGS

9A

EBII MH

1.622
1.526
1.464
1.214
1.048

1.469
1.435
1.232
1.000

IA64

1.101
1.118
1.065

116

asymmetric two-center shell model can give results very similar to those of Ref. 5 based on the
one-center deformed shell model in which the strength of the Y 3 and Y 5 deformations must
be carefully adjusted to reproduce the mass asymmetry.
(2)

Constancy of the mass of the heavy fragments

We tried to understand a very interesting result that the masses of the heavy fragments
are fairly constant (see Table 1).

In Fig. 2 is shown the dependence of the shell correctionenergies of the neutron and the proton on the nucleon number and the mass ratio at the second
saddle point (Z o

= 8.5 fm, 0 = 0.31), respectively.

From Fig. 2(a) , the energy gain in the shell correction energy of the neutron is about 5
MeV in the region of the neutron number 140 -

150, as the mass ratio increases from 1.0 to

2.0 and is most responsible for the mass asymmetry.

The large energy gain comes from therapid fall of the level [505] 11/2-, as was pointed out in Fig. 1.

~.
IWh \,\(' u t r-t m

z,.

8.5 fm

J = 0.3 1

'
,

I

"I

;::::

3 o·

~

2.0 '

-

"<-

de
,'.....,l-18''.v-.,''"• '\.;~o 7'~ -" ~:1~0\+ '~~ 1.4

4.0
~

,

l

" .... :............ : ,/~~.

\, ,/ . " 1.' 1.2\

1. 0~ - 1. 0 ",. ,,\.......

_

0-

.::?

\

\

~

'\.. ~--' 1.0
180\('utron number,-, ; '
} - 2.0" ... .",'

'J!

(f)

3.0

(a)

(h)

Fig. 2. The shell correction energy at the second saddle point (Zo = 8.5 fm, 0 = 0.31) as afunction of the mass ratio and the nucleon number. The single particle level of 236 U areused for the calculation of the shell correction energy.

The neutron number at which the shell correction energy is minimum decreases from 160
to 140 as the mass ratio increases from 1.4 to 1.6 in Fig. 2(a).
This tendency of the shell correction energy of the neutron is consistent with theconstancy of the mass of the heavy fragments through the isotopes.
In Fig. 2(b) , it can be seen that the energy gain in the shell correction energy of the protonwith the proton number 90 is about 2 MeV as the mass ratio increases from 1.0 to 2.0.

117However, the energy gain decreases as the proton number increases from 90 to 100. Theenergy gain is negative by about 1.5 MeV for the proton number 100, as the mass ratio
increases from 1.0 to 2.0.

The shell correction energy of the proton in Th and U region

enhances the ratio of the mass asymmetry, while in No and Fm region it reduces the ratio of
the mass asymmetry due to the shell correction energy of the neutron. Therefore, the constancyof the masses of the heavy fragments can qualitatively be understood for both isotopes andisotones in the actinide region.
The small discrepancy between the results shown in Table 1 and those of the above
discussion comes from the facts that the position of the second saddle point is different foreach nucleus, as can be seen in Table 1, and that the loss of the liquid-drop model energy
due to the increase of the mass ratio reduces the most favorable mass ratio predicted by theshell correction energy only.

References
1)V. M. Strutinsky: Nucl. Phys.,A95, 420 (1967); A122, 1 (1968).

2)

H. V. Groote and F. Hilf: Nucl. Phys.,AI29, 513 (1969).

3)

1. Maruhn and W. Gireiner: Zeit. Phys., 251, 431 (1972).

4)

P. Moller and 1. R. Nix: 3rd IAEA Symp. Physics and Chemistry of Fission, Rochester
1973 (lAEA, Vienna, 1974), Paper IAEA-SM-174/ 202.

5)

C. Gustafsson, P. Moller, and S. G. Nilsson: Phys. Letters, 34B, 349 (1971).

6)

B. L. Andersen: Phys. Letters, 42B, 307 (1972).

118

9. RADIATION CHEMISTRY AND RADIATION BIOLOGY

9-1.

Heavy-Ion Radiolysis of Liquid Aldehydes

M. Matsui and M. Imamura
We have reported the significant LET effects observed for liquid aliphatic ketones over a wide
LET range up to 90 eV /

A.1),

2)

In these studies, the radiolytic yields of the main gaseous products,o

H2 and CO , showed peaks in the range of LET = 50 - 70 eV / A, and the ratios of the two yields,
G(H 2 )/G(CO), increased steadily with an increase in LET. These results suggest the thermal
decomposition of free radicals and/or the formation of highly excited states in a confined volumeof the track cores of heavy-ion radiations.
An extensive study has been carried out also for some liquid aliphatic aldehydes; the preliminary
results obtained for propionaldehyde will be described in this report. Emphasis is put on theoradiolysis results in the relatively high LET region using N ions of 43 - 45 MeV (LET~65 eV/A).
The main gaseous products from aldehyde were H2 and CO , the yields of which were
determined by gas chromatography . Their yields increased steadily with an increase in LET; G(H2 )oand G(CO) at LET of 60 eV / A were approximately 5 and 2 , respectively. This result is in contrast
with the case of pure ketones and indicates that an excessive energies deposited in the track coreof high-LET particles may easily be transferred to the outside of the core , as in the case of
ketones containing a small amount of H2 O. However, in view of the increase of the ratio,
G(H2 )/G(CO) , with an increase in LET, thermal decomposition of free radicals produced fromexcited molecules must be important within high-LET tracks.
Major products other than H2 and CO were C2 -hydrocarbons: C2 H2 , C2 H4 , and C2H6 , whichwere not detected by gaschromatography from samples irradiated at low doses, however. They
were observed to form and increase at a dose above 2 x 10 19 e V. The yields of H2 and CO showed
no dose dependency .
It has been demonstrated 3 ),4) that liquid aldehydes containing olefin hydrocarbons produce

telomers, RCO(CH 2 -CH2)nR (R=alkyl radicals) , by 'Y-ray irradiation, and that the degree oftelomerization increases with temperature. In the present study, a considerable amount of liquidwith high boiling point was produced at a dose of around I x 10 19 eV , where no C2 -hydrocarbons
were detected. This product did not contain diethylketone (n=O), and presumably comprises
several kinds of telomers. The production of C2 -hydrocarbons above 2 x 10 19 eV is considered
to be due to the secondary radiolytic decomposition of these telomers. Further studies are in
progress.

1 19

References
1)

M. Matsui, M. Imamura, and T. Karasawa: IPCR Cyclotron Progr. Rep., -5, 90 (1971); -7,
112 (1973).

2)

M. Matsui and M. Imamura: Bull. Chern. Soc. Japan, 47, 1113 (1974).

3)

K. Hirota and M. Hatada: ibid. , 33, 1682 (1960); K. Hirota, S. Iizuka, H. Ochi, and M.
Hatada: ibid., 36, 115 (1963).

4)

C. E. Stoops and C. L. Furrow: J. Org. Chern., 26, 3264 (1961).

120

9-2.

Optical and ESR Studies on Single Crystals of KBr and CdS
Irradiated with Heavy Ions

K. Kimura, M. Matsui, and M. Imamura

Interaction of ionizing radiations with condensed matter produces highly excited states along
their paths. Several short-lived species (excited states, excitons, ions, electrons, and neutral free
radicals) are formed in the next physico-chemical stage. These species are localized in the vicinityof the radiation paths for a short time, forming spurs or tracks; the spatial distribution of these
species is dependent upon the LET of the radiation.
Several studies have been made on the spatial distribution of these intermediates species in
X- or 'Y-ray irradiated glasses and solids, but quite few in heavy ion-irradiated systems. Heavyions having LET much higher than that of X- or 'Y-rays may give higher local concentrations of
the species with different spatial distribution.
We have already reported ESR studies on some organic crystals irradiated with heavy ions. 1),2)

It was found that these studies could provide valuable information on the spatial distribution ofintermediate species, and therefore on the primary processes of radiation chemistry.
This report presents the results of color-center formation in KBr and emission from CdS by
C-ion irradiation.

(1)

Color centers produced in KBr single crystals

KBr single crystals were subjected to 85-MeV C-ion irradiation at 77 K, and their opticalabsorption and ESR spectra were recorded. 60Co--y irradiation was also carried out for comparison.

0.8

0.6
.~
u

_ 0.4

8
0-

o

0.2

Wove length( nm )

Fig. 1. Absorption spectra of the C ion-irradiated (a) andthe 'Y-irradiated (b) KBr single crystals recorded at
77 K.

121

Figure 1 shows the electronic spectra. The species having a peak at 600 nm may be
assigned to the F-center. The V k-center ("'max = 410 nm) was not observed for the C
ion-irradiated sample. In contrast, the V 4 -center, which was not observed for the r-irradiatedsample, appeared at 275 nm. The significant difference in the electronic spectra may be due tothe thermal effect in heavy-ion tracks or an essentially different process between the twC'
systems.
ESR spectra of the F-center are shown in Figs. 2 and 3. These spectra were recorded at

10 0 gauss

Fig. 2. ESR spectrum of the Cion-irradiated KBr
single crystal recorded at 77 K after annealing
at l30K.

Fig. 3. ESR spectrum of the r-irradiated KBr single
crystal recorded at 77 K after annealing at
130 K. Arrows indicate Mn 2+ standard signals.

122

77 K after annealing the samples at 130 K; the annealing eliminated the spectra due to species
other than F-centers. The linewidth of the spectrum for the C ion-irradiated sample is only aquarter of that for the ,),-irradiated one.
The linewidth sharpening may be accounted for in terms of the exchange narrowing between
F-centers trapped closely in the C ion-irradiated sample. In fact, on increasing the temperatureof the C ion-irradiated sample to about 200 K, at which the F -centers become mobile , its
linewidth showed broadening to the same extent as that for the ,),-irradiated one. This argument
is also supported by the experimental results on power saturation. A mean separation between
F-centers in the C ion-irradiated sample was estimated to be 4 - 5 lattice units.
(2)

Emission from CdS single crystals.

Determination of emission spectra during heavy-ion irradiation is one of the important
experiment which may provide information on the nature of excited states produced by heavy-ion
irradiation. No similar studies have been reported so far.
Preliminary experiments have been carried out to detect emission spectra from CdS single
crystals under 85- MeV C-ion irradiation. Emission could be detected successfully and its
spectrum was recorded by use of a monochromator and a photomultiplier; the spectrum gives
peaks between 480 and 500 nm. However, owing to the weakness of the emission, no detailed
results are available at this time. Improvement of the apparatus is now going on.

References
1)

K. Kimura, M. Kikuchi, M. Matsui, T. Karasawa, M. Imamura, Y. Tabata, and K. Oshima:
IPCR Cyclotron Progr. Rep., ~, 110 (1972).

2)

K. Kimura, M. Matsui, T. Karasawa, and M. Imamura: ibid., 2, 114 (1973).

123

9-3.

LET Effect on the Radiation-Induced
Polymerization of Styrene

T. Yasukawa, T. Takahashi, M. Matsui, and M. Imamura
Radiation-induced polymerization in bulk and solutions is not a homogeneous reaction,
because primary radicals or ions produced by irradiation are distributed inhomogeneously in spurs
or tracks. Fair portions of active species are deactivated by neutralization or recombination inspurs without participation in polymerization, and only those active species which escape spurs
initiate polymerization reactions. Under ordinary conditions, radiation-induced polymerization ofstyrene proceeds following the radical mechanism and polystyryl radicals are mostly deactivatedby the recombination between them. The coupling between polymeric radicals is diffusion-controlled
and consequently considered sensitive to the degree of polymerization of polymeric radicals. For
the time being, however, the chain-length effects on the coupling process of polymeric radicals
have not been elucidated sufficiently.
The chain-length distribution of polymer reflects accordingly the initial distribution ofprimary active species and the coupling processes of polymeric radicals. Hence, it would afford
valuable information to investigate the LET effects on the molecular weight distribution ofpolystyrene obtained by various kinds of radiation.
Table 1. The G-values of gaseous products and polystyrene in the Cion-induced
polymerization reaction of styrene. At room temperature and the total
dose of 4.1 x 10 18 eV in vacuo.

Polymer

Product
G-value

1.34

0.21

0.03

0.87

0.04

Purified styrene sealed in vacuo in an irradiation vessel equipped with a thin Al window was
irradiated with 83 MeV C ions to a dose of 4.1 X 10 18 eV. Irradiated solutions were degassed byfreeze-thaw cycles, and gaseous products were analyzed by gaschromatography. Polymer was
separated from styrene monomer by vacuum distillation. Table 1 shows the G-values of gaseous
products and polymer. The composition and the G-values of gaseous products are similar to
those of ordinary compounds whereas the G-value of polymer chains is considerably small. The
molecular weight distribution of polystyrene is shown in Fig. 1. Fair portions of polymer have amolecular weight larger than 1 x 106 ; this fact shows that some polymeric radicals have
lifetimes as long as lOs. Different from ordinary polystyrenes obtained by radical initiators or

124

c

o

.::; 1u~O +---~~--~~--~--~~--~-----.--------~o10l\loi e c ui a r II"e ig ht

X lO - 5

Fig. 1. Molecular weight distribution of polystyrene
obtained by C-ion irradiation at room
temperature. Energy of incident C-ions was
17.0 MeV and a total dose was 4.1 x 10 18 eV.

Mo lec ular

we ight

X 10 - 5

Fig. 2. Molecular weight distribution ofpolystyrene obtained by electron
irradiation at 30 °C. Total dose was
6 x 10 18 eV/g.

photo-polymerization, the polystyrene obtained by C-ion irradiation has a considerably large valueof Mw/Mn = 4.48. (Mw and Mn stand for the weight-average and number-average molecularweights, respectively.) These results suggest that growing radicals are not distributed homogeneously
in solution. After all, we may well consider that in the C ion-induced polymerization of styrene,
only a small portion of primary radicals «1 %) escapes the tracks to initiate polymerization

reaction effectively , and that spatial distribution of growing radicals is considerably inhomogeneous.
In order to avoid secondary reactions, electron irradiation of styrene was carried out by meansof a flow method. Styrene flowing in a stainless-steel pipe of 4 mm ¢ was irradiated with 1.5 MeV

125electrons through a slit 5 mm wide. Styrene monomer was circulated by using a gear pump at a
rate of 10 m£/s at 30°C; the dose rate was ca. 3 X 10 18 eV/g. s.
Figure 2 shows the molecular weight distribution of polymer obtained under these conditions.
Different from Fig. I, the distribution is fairly sharp and Mn is small. Although experimental
conditions were considerably different from those for the C-ion irradiation, these results suggestthat growing radicals are distributed homogeneously in respective volume elements of styrene
flowing in the pipe.
Details of the experiments and discussion will be published elsewhere.

126

9-4.

Inactivation of aRadioresistant Vegetative Bacterium Micrococcus
radioduransby Charged

Partie lesA. Matsuyama, T. Takahashi, and F. Yatagai

Since the repair capacity for radiation damages in DNA is expected to affect the LET effectupon bacterial inactivation, it is interesting to investigate the inactivation of repair-proficient
bacteria by charged particles of different LET's. Micrococcus radiodurans has been found to havean efficient DNA repair capacity which may be responsible for its extraordinary resistance to"(- and X-rays. 1)- 4) Thus, in a series of our studies on bacterial inactivation by cyclotron beams,
the LET dependence of the cellular radiosensitivity of M. radiodurans was determined under thesame experimental condition as~. coli, and the results obtained were compared with thosereported by Dewey.S)
Since the parameters of the survival curve of M. radiodurans considerably varied according
to conditions, care was taken for the preparation of cell suspensions to be irradiated. M.
radiodurans was grown overnight in a TGY broth (0.5 % Difco tryptone, 0.1 % glucose, and 0.3 %yeast extract; pH 7.0) at 37° C in a shaker culture under an aerobic condition. A 0.5 mt portionof the first culture was transferred into a lOme fresh TGY broth, and after 4 h of the second
incubation at the same temperature, log-phase cells were centrifuged and washed twice with a
0.067 M phosphate buffer. The cell pellet obtained was maintained in an ice bath until use.
Immediately before irradiation, cells were suspended in the 0.067 M phosphate buffer at aconcentration of about 1 x 10- 8 cells/mf. Preparation of the monolayer of bacterial cells on
membrane filters and irradiation were performed as previously described. 6) Survivors were
determined by plating appropriate dilutions on a TGY agar.
Some examples of survival curves determined for a-particles, carbon, and nitrogen ions as well
as 60Co "(-rays are shown in Fig. 1. M. radiodurans gave the non-exponential survival curveconsisting of a shoulder, followed by an exponential slope not only for 60Co "(-rays but also for
all charged particles used in this study. This observation is compatible with the results obtainedby Dewey (the same bacterium)S) and by Mortimer et al. (yeasts).7) However, Todd 8 ) reported
that the survival curve of cultured mammalian cells becomes exponential in the LET region higher
than about 220 keY/11m and the shoulder disappears from the curve.

LET dependence of thelength of the shoulder and the inactivation constant (k) calculated from the exponential slope
are shown in Figs. 2 and 3, respectively.

The results can be tentatively summarized as follows:(I) the length of the shoulder on the survival curve increases with increasing LET, especially in
the LET region for heavy ions, (2) the inactivation constant k appears to decrease without any
distinct peak as LET increases, and (3) the effective inactivation cross section (Seff) for the
exponential slope, which represents the relative effectiveness per particle, is remarkably dependent
upon LET in the region for a-particles, but little dependence is observed for heavy ions (Fig. 4).

1000

3000
2000
Dose ( krad )

o

o

o

o

6

C- ions
N- ions50

o 60Co Y - r ays
o a- par· ti cIes

00

o

o

o

0

100
200
LET . ( keV / j.l m)

o

6

0

6

o

0~

1000

66

o 0

~

500

o
o

0J.!)

o

6

Fig. 1. Survival curves of M. radiodurans.

2000

the reciprocal of D37 for the exponential slope.)

M. radiodurans. (The inactivation constant k is

for the exponential slope of survival curves ofFig. 3. LET dependence of inactivation constant (k);:::::,

:a

~ 10

::0-

15

10- 5

4000

o

6

o
50

C - ions;\1- ions

o
o

0

o

0

100
200
LET . (keV / j.lm )

0

500

@~~

~

1000

6

o
6

~0

0

o

2000

0.01

0.02

50

o

o

o

o

8

200
100
L ET . ( keV / j.lm )

o

o

o

500

C - ions

1000o )J - ions

6

2000

o a-pa rti c les000<!h0 000 66 6~~(!fsection (Seff) for M. radiodurans.

Fig. 4. LET dependence of effective inactivation cross

(f)

:::t.

~ 0.05E

0. 10

on survival curves of M. radiodurans.

Fig. 2. LET dependence of the length of the shoulder

(f)

~

-0

-0

:;

10- 4

.~ 10

(f)

-3

6

go
~

o 60 Co Y- r ays
o a- pa r ti c les

.-

'"

if)

2

o

o

~

-0

:;E

..t 10

'"

u

1

-2

" 10-

.~

Ell 60Co Y - r ays
a - pa r t ic les
6
C- ionso N - ion so-....)N

128

The result concerning LET dependence of the shoulder length is consistent with that obtainedby DeweyS) as mentioned above, whereas changes in the inactivation constant appear somewhat
different.

Further determination and analysis of the data are now under way.

(The results

described here are also slightly different from those reported in previous notes 6 ),9) of this series.
The difference might be partly due to different experimental conditions, which will be discussed
in the future study.)

References
I)

B. E. B. Mosely and H. Laser: Nature, 206, 373 (1965).

2)

C. J. Dean, P. Feldschreiber, and J. T. Lett: ibid., 209,49 (1966).

3)

S. Kitayama and A. Matsuyama: Biochem. Biophys. Res. Commun., 33, 418 (1968).

4)

A. D. Burrell, P. Fe1dschreiber, and C. 1. Dean: Biochim. Biophys. Acta, 247, 38 (1971).

5)

D. L. Dewey: Int. J. Radiat. BioI., 16, 583 (1969).

6)

A. Matsuyama, T. Karasawa, S. Kitayama, and R. Takeshita: IPCR Cyclotron Progr. Rep.,~,

101 (1969).

7)

R. Mortimer, T. Brustad, and D. V. Cormack: Radiat. Res., 26, 465 (1965).

8)

P. Todd: Radiat. Res. Suppl.,2, 196 (1967).

9)A. Matsuyama, T. Karasawa, T. Takahashi, Y. Asano, K. Igarashi, H. Kano, E. Fukuda, and
Y. Ando: IPCR Cyclotron Progr. Rep., :!> 132 (1970).

129

9-5.

LET Effects on Production of DNA Single-Strand Breaks and Their
Repair in £. coli B/r

K. Igarashi, F. Yatagai, T. Takahashi, and A. Matsuyama

In a previous paper,l) it was reported that the efficiency of production of DNA single-strand
breaks in E. coli Bs- 1 decreases proportionally with increasing LET 00 above 90 keY Ipm. Since
there are pieces of evidence that DNA is a target molecule for bacterial inactivation, the LET
effect on DNA-strand breakage in bacterial cells endowed with different DNA-repair capacities has
been investigated. In this report, the production and repair of DNA single-strand breaks in E.
coli Blr cells irradiated with a-particles and nitrogen ions accelerated in the cyclotron are described.
For comparison, irradiation with 60Co 'Y-rays was also carried out. Procedures of irradiation anddetermination of DNA single-strand breaks in log-phase cells of E. coli Blr labeled with
3H-thymidine were the same as previously reported. 1) - 3)
Survival curves of E. coli Blr determined for 60Co ,),-rays, a-particles, and nitrogen ions were
all exponential. Figure I shows the sedimentation profiles in alkaline sucrose gradients of
3H-DNA from E. coli Blr cells irradiated with these three kinds of radiation. For all types of---radiation used here, irradiation was performed with three different doses giving surviving
fractions of 1 x 10- 2, 1 x 10- 4, and 1 x 10- 6 in order to confirm the linear relationshipbetween the number of DNA-strand breaks and dose. Using values of the number-averagemolecular weight of DNA calculated from the sedimentation profiles, one can obtain thedose-response curves for DNA-strand breakage produced by radiations and then values of theefficiency of DNA single-strand break production, Esb (eV Ibreak). As can be seen in Fig. 2, Esb
increases with increasing LEToo. Although the number of data obtained with E. coli Blr is still---insufficient, it appears that Esb can be regarded as a linear function of LET 00 and the LET 00 -Esb
curve for nitrogen ions shifts to the higher LET side as compared with that for a-particles.
These results obtained with strain Blr are consistent with those reported with strain BS - 1 .
However, Esb values of strain Blr were larger than those of strain BS- 1 at the same LET. Thisdifference in Esb values between these two strains will be examined in further determinations.
In order to compare the rates of DNA repair after exposure to 60Co ')'-rays and nitrogenions, cells were reincubated at 37°C for 40 min after irradiation.

Fi~ure 3 shows examples ofsedimentation profiles of 3H-DNA during the course of post-,irradiation- incubation. Both doses
indicated in Fig. 3 gave a surviving fraction of 1 x 10- 4 . Relationships between the time ofpost-irradiation incubation and the number of DNA single-strand breaks calculated fromsedimentation profiles during post-irradiation incubation are illustrated in Fig. 4. The results
indicate that DNA single-strand breaks are hardly repaired after the exposure to nitrogen ions,while they are appreciably rejoined after ')'-ray irradiation, and that nitrogen ions produce asmaller number of single breaks than ')'-rays at the same cell survival lebel (Fig. 4).

130

10

(a )

Q'

- par'ticl e s
11.44 MeV / a mu }( h ):\-ion s
14,75 i\! e \ ' / am u 1

10 -

Dose:
(a) 0 ,38.6 krad; -,57.4 krad; 6,77.6 krad(b) o , 42.8 krad; -,80.2 krad; 6, 140 krad(c) 0, 28.0 krad; -, 56.0 krad; 6 , 112 krad
40
Ie )Surviving fraction:Co- 60 Y- ru ys(a) and (b) 0 , 1 x 10- 2 ; -,Ix 10- 4 ; 6, 1 x 10- 610(c) o , 1 x 10- 1 ;_, 1 x 10- 2 ; 0 ,1 x 10- 4

Fig. 1. Sedimentation profiles of 3H-DNA
from E. coli B/r immediately after
irradiation.
Sed im en ta tion distance

I mm

)

2000

1000
c::o
U)

........

>Il!

500

~
~

200

/
100

100

200

500

1000

2000

LET , ( k e V / Jl m )Fig. 2. LET dependence of the efficiency of DNA single-strand break production (E sb )in §.. coli B/r. 6, a-particles ;0 ,nitrogen ions.

131~ - io ns

104, 75 l\l e \ ' / a mu \ 80, 2 k ,'a d )

.s'"
':;

Cu -60 Y - r a ~' s

:);

~c

( 112 krad )

<D'
.<I?,
I

u

;t

.
..

, ft.':);

i'8'B :\' , .l'\

10

II

,

"
"
~'
,/

,

I

,e

I ,
:

"

:

•

"
,
'/

ttI...

;,;
"

':S
'(\

~

ell..

I

~
\I

,

'A

,

.

'-\

II

tJjBe
,

I

I
I

I,

I

'tr{ \ \l:u. El'·'T'.\~

"

#.1

II

\

'"

~

•

I

I

\l)1'
\ I

•

ft·-'

20

40

M e n isc us

Se dim e ntati o n di s ta n c e ( mm )0 , Unirradiated;., Irradiated, no reincubation ;8 , CD ,and @ , Irradiated, reincubated for 5, 15 ,and 40 min, respectively.
Fig. 3. Sedimentation profiles of 3H-DNA from §..
coli Blr after post-irradiation incubation.

I

g

IOJ7~

Fig. 4. Changes in number of radiation-produced~.t ~ ~oDNA single-strand breaks in §.. coli Blr0during post-irradiation incubation. A and.----_:©l~C--=tg-----=e-------il-----_.

B: 112 krad and 56 krad of 60Co :y-rays,

respectively ; C and D: 80.2 krad andoZ@--- p---

IOJ

l
o

---- - - - - ---@------If-----_e

Ii

!

10

15

1/

M in, of pos t i l'rad ia ti o n in c ub a tion a t 37"~40

42.4 krad of nitrogen ions, respectively.
Surviving fraction : A and C, 1 x 10- 4 ;B an d D, 1 x 10 - 2.

132

References
1)

K. Igarashi, F. Yatagai, T. Takahashi, and A. Matsuyama: 1. Radiat. Res., 15, 148 (1974).

2)

A. Matsuyama, T. Karasawa, S. Kitayama, and R. Takeshita: IPCR Cyclotron Progr. Rep.,
3, 101 (1969).

3)

K. Igarashi, F. Yatagai, T. Takahashi, and A. Matsuyama: ibid., 7, 122 (1973).

133

1o. PREPARATION OF RADIOISOTOPES AND LABELED COMPOUNDS

10-1.

Production of Radio'isotopes and Preparation oflabeled Compounds for Medical Use

T. Nozaki, S. Ambe, M. Iwamoto, A. Tahara, T. Ohsawa,T. Karasawa, M. Okano, T. Ido, K. Fukushi, K. Suzuki,
L. Iwata, T. Hara, and K. Taki
We have continued our work on the preparation of 18F-organic compounds and themeasurement of their in vivo distributions. The production of 28Mg and 13NH3 and the preparationof seleno-methionine labeled with nSe and 73Se have also been studied. Further, our production
techniques for 43K and 123 1 recently have been notably improved.
By the reaction of Ag 18F with 6-chloro-9-benzylpurine in toluene, 6-fluoro-9-benzylpurine- 18 F
was prepared. This compound was found to have a marked tendency of being concentrated inbrain. The 18F-labeling of some physiologically active steroids has aroused our interests for medical
use. Introduction of ISF-atom into the steroid molecule was completed by cleavage of epoxidering with B 1S F 3· Et 0. The utilization of other fluorinating reagents (e.g., CF 30 18 F) is now under2

study.
The yields of 28Mg for triton-induced reactions were already reported. I) Possible ex-particle
reactions for the production of 2SMg were also examined, and a convenient process for the
carrier-free separation of 2SMg from an aluminum target was devised. A paper describing detailsof these studies is in press. 2)
The proton bombardment of water has been used for the production of 13N. The excitation
curve for the reaction of 16 0 (p, ex) 13N was measured; a 13N activity sufficient for diagnostic use
is shown to be obtained by this bombardment even for an incident energy of 9 MeV. A major
portion of the 13N thus produced in water was found to be usually in anionic states. The 13N
was converted into carrier- and salt-free 13NH3 by a reductive distillation, and its distribution inmice was measured. The 13NH3 has proved to be useful in heart scanning.
Now in Japan, two medical-use cyclotrons are under trial operation and a so-called Baby
Cyclotron capable of producing only llC, 13N, lSO,and lSF is under construction. Most of ourpresent experiments are so designed as to give good empirical bases for _satisfactory uses of eachof the new machines.

References
1)

T. Nozaki, M. Furukawa, S. Kume, and R. Seki: IPCR Cyclotron Progr. Rep., ~, 83 (1971).

2)

T. Nozaki, M. Furukawa, S. Kume, and R. Seki: Int. J. Appl. Radiat. Isotopes, ( in press. )13,1

11. RADIATION MONITORING

11 -1.

Routine Mon itoring

K. Koda, 1. Sakamoto, and I. Usuba
Results of routine monitoring on the cyclotron obtained from January to December 1973
are described.
No remarkable change in leakage radiation and residual activities was observed during thisperiod.

(1)

Surface contamination

The surface contamination of the floor of the cyclotron room , where the highest level ofcontamination had usually been detected in the cyclotron building, has been kept to be about

10- 6 - 10- 7 J1Ci/ cm 2 as a result of wiping-off of the floor twice a year.
(2)

Drainage

The concentrations of radioactive nuclides in drain water and sediments in the drainage tankof the cyclotron building were measured and found to be of the order of 10- 7 J1Ci/ cm 3 and10- 4 J1 Ci/ cm 3 , respectively. This difference would have been caused by the nbsorption ofradioactive nuclides dissolved in drain water by the sediment.
(3)

Personnel monitoring

Owing to the revision of the regulation of the work in the cyclotron vault as described in aprevious report,1) the exposure of workers decreased remarkably as shown in Table 1.
It was shown that no one received a dose above lOOO mrem and the average value of dose

per person in this period was cut down to less than one-half of that in the previous year.

135

Table 1. Annual exposure dose distribution of the workers and average dose from1969 to 1973.
(Dose accumulated from April to next March.)

Year

Total numberof workers

Dose distribution(mrem)
A
Unde:
10
101
301 >1000
tectable

100

300

1000

Average dose
per person(mrem)

1969

46

11

17

16

2

318

1970

49

19

12

15

3

299

1971

50

7

15

15

12

261

1972

47

10

17

12

7

199

1973

48

14

22

11

1

0

Reference
1)

K. Koda, I. Sakamoto, and I. Usuba: IPCR Cyclotron Progr. Rep., 2, 134 (1973).

79

136

12. A NEW MACHINE

12-1.

The Variable-Frequency Linac ProjectStatus atAutumn1974

M.OderaIt was admitted by the Government to start the construction of a linac cavity in the 1974

fiscal year. A team for detailed engineering design was organized and investigations including
experimentation with cavity models and manufacturing of prototype drift tubes and modulated
light signal transmitting, receiving, and decoding circuits to be used in an injector system are in
progress. Discussions on fabrication techniques are being made with several firms.
Owing to inflation at a rocketing rate from the fall of the last year, we have met difficulties
to procure things with the expenses estimated in the budget proposed at the beginning of 1973.
Some alterations in specifications of several components were inevitable. Fortunately, for thevacuum system, a development of new type pumps seems to warrant the spesifications without
much degrading its performance. To change the design of the radiofrequency resonator is moredifficult and its possibility is still being investigated .

..:'\Air core (3-ray spectrographFig. 1. Site of the planned linac building near the cyclotron facilities.

137

Our building schedule is lengthened by one year because of delay of installation of air
conditioning equipment and pushing up of the cost.
A design study of cavity using models has almost completed. A continuous operation for
the range of frequency from 18 to 43 MHz seems to be assured and on a reduced duty factor amuch wider range is usable if an obround shape for the cavity cross section is chosen. The
cavity models will be discussed in the following reports. The site of construction under plan isindicated in Fig. 1. It is on a slope slanting down westward from just outside of the shielding
wall of the cyclotron experimental area. Excavation of the ground will begin next summer.

138

12-2.

Design Study Using Cavity Models

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

We studied following subjects using cavity models at atmospheric pressure.
(1)

Determination of details of cavity parameters: Since field patterns around the drift tubes

are difficult to estimate accurately by calculation owing to smallness of symmetry of the structureof the cavity, the pattern and the highest frequency have to be determined by experiment.
(2)

Estimation of power loss: For the same reason stated above, the power loss at higher

frequencies has to be estimated by the models.
(3)

Field distribution along the acceleration axis: This is necessary for the determinationof drift tube length.
(4)

Search of parasitic resonances. Though the fundamental resonant frequency isdetermined by the length of center stem and the capacity of drift tube and so only a simple
spectrum for higher resonant frequencies is expected, particular construction of the cavity might
induce odd resonances unexpected. It is desirable to know whether or not those unwanted
resonances exist and interfere with the fundamental mode.
Table 1. Summary of results obtained by studying models.
Type of cavity
Resonant frequency (MHz)

II

ill

IV

18 - 50

15 - 40

17.5 - 56

18 - 49

15 - 3817.5 - 45

18 - 45

15 - 40

17.5 - 43

Frequency range for uniform voltage
distribu tion (MHz)Frequency range within power limit (MHz)Four models were tested and the results were used for the design of real cavities. Table 1
shows a brief summary of the test. Model I is omitted there since its role was mainly exploratory.
In Table 1, the range of frequency is given for 2,000 mm stroke for the shorting plane, thecriterion of uniformity for voltage is ± 10 % and the power loss limit means an electrical shunt
impedance larger than 200 kn. The last value gives a power dissipation within 230 kW for peakvoltage 300 kV across the tube gap.

139

12-3.

Summary of Measurements on Electrical Characteristics ofModel Cavities

I and

II

M. Odera and Y. Chiba
Since a new configuration of a resonator is planned as an accelerating structure of the linac,
detailed investigation of the characteristics of the resonator has been made for these years.
Figures 1 and 2 show dimensions of two real scale models of cavities II) and II. They
differ in the method of frequency change and in the material of fabrication. The model II has asingle shorting plane movable along the center stem and is made of plywoods lined with thincopper plates, whereas the model I has two moving panels and two large capacity compensatorsand is fully made of aluminum.
Model I, which is the first model constructed, was used to survey the working principle ofthe quarter wave resonator having a large width compared with the length and loaded heavily
with drift tubes at the voltage loop. 1) It was made to be able to change volume of various parts
separately and freely to find out any odd resonances and the effect of asymmetry of the structure.
No significant odd mode was found, but degradation of quality factors was clearly observed whena right-left asymmetry was introduced about a plane including the acceleration axis and the center
stem. In studying the performance of this model by use of a perturbation technique we proved
the validity of the principle of the cavity; namely, the voltage distribution along the acceleration
axis is fairly uniform for a wide frequency range,2) which permits acceleration of ions withdifferent mass to charge ratios at different frequencies, and the frequency spectra of higher modes

-I

®
o

Lr)

o

o

..-<

o

0>

-1500
1001-

1_·_ _ _ _ !/-=-:
25"--"--"
0o'-------_~1

1400

1~----------_1!~2~7=00~---------

I

Fig. 1. Modell: CD center stem; ® drift tubes at ground potential, the outer
diameter being 130 mm; ® drift tubes at radiofrequency high voltage,
the outer diameter being 60 mm; @ capacity compensators; ®
movable panels; and ® outer conductors.

140,__________~11~2=8=00~------~

~®

@~

t1

f---

@)

o

U")

CD

o
o

"<:!'

........

M........

1 18001/_~1

I~
1200

_ -------------'30'-'-0-"--0 1/, _____________

Fig. 2. Model II; CD center stem; ® drift tubes at ground potential, the outer
diameter being 160 mm; ® drift tubes at radiofrequency high voltage ,the outer diameter being 130 mm; and @) movable shorting plane.

20.000°""'"'1

18 .000

F eede r=I

16 .000-x-

t = 23 mm---e - - -t = 13mm

<Jl
Q.I

~

14.00012 . 000

10. 000

x\

8. 000
20

30

40

50

60

I""."eq uenc y l\ IH z

Fig. 3. An example of the effect of couplingstrength of a detector or a feeder with acavity on measured quality factors. The
values are for the model II with drift
tubes removed.

141

are simple 2) and discrimination of them presents no problem in operation.
Model II was constructed as a full-sized model in which a shorting plane was used as a device
for frequency change. It was mainly used to estimate power dissipation especially at higher
frequencies. The method of measurements is shown in Fig. 1 in an article 12-12 in this Progress
Report,3) and is the same as that used in the design work of the cyclotron ,4) except a PIN diodebridge was used instead of a vacuum tube as a switching element. Power feeding and signal
pick-up were made by capacitive probes attached to one side of the cav ity .
Figure 3 shows the effect of coupling strength on the measured Q values suggesting larger
true values for a cavity when loading by a generator or a detector was able to be eliminated.
Figure 4 shows the Q values and electrical shunt impedances obtained by this method. The
latter is defined here as (peak voltage across drift tube gaps)2/(2X power loss). This curve is ofservice to estimate the radiofrequency power required for this type of cavity.
Mode l IJ

800
15.000
700

600

C 500

10.000 8'

-

-'"
J>

0:

400
Rs
300
5.000
200

100

0
20

40

30

50

i\ IH zFig. 4. Quality factors Q and electrical shunt impedance Rs
as a function of resonant frequency.

References
1)

M. Odera: IPCR Cyclotron Progr. Rep ., 6, 16 (1972).

2)

M. Odera, T. Tonuma, M. Hemmi, and Y. Chiba: ibid., Z, 143 (1973).

3)

S. Takeda: ibid., §., 157

4)

M. Odera, Y. Chiba, T. Fujisawa, Y. Miyazawa, and O. Terajima: Sci. Papers I.P.C.R., 67,
99 (1973).

(1974).

142

12-4.

Voltage Distribution at the Gap of Model IIwith theDrift Tubes Removed

Y. Chiba and M. Odera

Voltage distributions along the axis of acceleration of various models show several
characteristic features in common: distinct change of distribution according to harmonic numbers;
voltage drop at both extreme gaps which becomes more distinct at higher frequencies; and variationof voltage more remarkable than the corresponding error of gap length.

In order to study the nature of these characteristics, the drift tubes were removed andspacers made of copper plates were inserted to give a capacity equivalent to that of drift tubes.
Figure 1 shows one of the settings and Fig. 2 an example of corresponding field distributions.
The curves show high sensitivity for small undulation on the surface of copper plates and thedistinct change of voltage distribution according to the harmonic number is also clearly observed
here. These patterns can be easily explained and the corresponding frequencies be estimatedapproximately by postulating resonances in the parallelepiped volume which is formed by
cutting half the cavity through the center symmetry plane induding the acceleration axis. There
are other resonances at very high frequencies which resemble an H-type mode of cylindrical cavities.
Next, a part of the gap was made narrow to see the effect of local deviation of capacity
distribution. Figure 3 shows its geometry and voltage distribution thereof. A gradual elevationof field strength towards the part having high capacity was seen. This effect of nonuniform
distribution of capacity or other parameters upon field deviation also present in the Alvarez and
c..
<Il

lJ

E

E

M

"'"'

E

E
E

E

"':

"':

".,

If")

"'"'

"'"'
I

~

E

:;;

81j
WI L t

j

01

I
!

E

II
L
~l
T

F

s

~ M

\\

Fig. 1. Model II with drift tubes replaced with spacers.
S, center stem; D, detector probe; F, power
feeder; B, metal bead ; M, motor to drive astring for translation of bead through gap;
W, weight to give tension to the string; h,distance of shorting plane from theaccelera tion axis.

143

f o = 54 . 26 MHz

h = 38 cm

C 100mm 20mm

'<~1L

~
wit h C25mm

f o = 37. 27 MHz

h = 58 em

wit hout C

fo = 43.06 MHz

h = 58 ern

Posit ion of beadFig. 2. Field patterns expressed by frequency

Fig. 3. Effect of local deviation of capacity along the

distribution. Numbers following a letter

acceleration axis. Reversal of slope off denote order of harmonics.

distribution shall be noted.

Inter-digital H-type resonators. The sloping of field strength may be expressed in another way
that the field strength is larger around the part where local resonant frequency is lower than inother parts of the cavity. Such an effect explains the phenomenon mentioned in the first part,
namely, the field strength in the narrow gap is elevated more than the value given by the valueof gap length. It would be possible to describe this phenomenon quantitatively by considering
local deviation of high frequency current. However we were satisfied using the knowledge for
improvement of the characteristics of the cavity which proved to be very useful.
The lowering of field strength at the extreme gaps when the open end of the cavity is loadedwith drift tubes may be accounted for by adding the tank-end effect similar to that of H-type
resonator to the above effect of local parameters deviation which is inevitable for the extreme
gaps.

144

12-5.

Results of Measurements on Model III of Linac Cavity
having a

Stem of Circular-Shape

M.OderaModel II , which has a stem of a rectangular shape, has excellent electrical characteristics 1)such as a wide frequency range, ease of discrimination of higher modes, good Q factors, anduniformity of voltage distribution along the acceleration axis. However, its mechanical construction
is not very advantageous for actual fabrication, especially when a single shell structure is adopted,2)
and the outer conductor has to support the atmospheric pressure as well as high frequency currents.
If a circular shape can be used, most of the mechanical difficulties of a single shell structure

would be eliminated. Model III was manufactured to investigate this possibility. It was made of
plywoods and lined with copper plates. It has a polygonal cross section instead of circular on
account of prompt fabrication. Figure 1 shows the structure of model ill.

o~......

r

g
<D

~

I

L \- dI-'- - -

Iit

15D-t-2 00-J....-

T- -650- - -1000- - --

----1

o
~

I

o
o

tI

Fig. 1. Model ill: 1, center stem; 2, drift tubes at ground potential; 3, drift
tubes at radiofrequency high voltage; 4, shorting plane; 5, liners whichbound a volume around each drift tube.

145

As expected, voltage distribution is not very favorable Hnd various improvements were triedby shaping volume around drift tubes. Figure 2 gives an example showing the effect of shaping.
Although the method was very effective, the distribution comparable to those obtained for therectangular one at 50 MHz was unable to be realized above 40 MHz. On the other hand, the quality
factors were superior to model IT reflecting more uniform current density around the stem ofmodel Ill.

l.0

c

-~

'"
"

<ll
-0

~

~

0.5

50
~
o

'"

0::

3

4

5

7

6

8

9

10

Gap numbe r

Fig. 2. Variation of field pattern along the acceleration axis
by change of the shape of volume around the drift
tube.
Curve A:d = 170w = 330

Curve B:d = 170

w = 490

Curve C:d=0

w = 1220

Voltage distribution is given by square-root of theratio of frequency deviation.

ReferencesI)

M. Odera and Y. Chiba: IPCR Cyclotron Progr. Rep., 8,139 (1974).

2)

LinacDesigngroup: ibid.,p. 148.

146

12-6.

Results of Measurements on the Model IV of the

Linac Cavity

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

The model IV is a scaled model by 1/2.5 of a configuration chosen as a structure of the firstcavity. Figure 1 shows its construction. It is made of plywoods lined with copper plates as wasdone in the model ill. The characteristic impedance of transmission line is 32 ohm. Figure 2
gives its resonant frequencies as a function of position of the shorting plane . Overall property ofthis model is similar to that of the model n but by shaping the volume around the drift tubes as
was done in the model ill , a wider frequency change was found possible . As is seen in Fig. 2,
it can resonate from 17.5 to 55 MHz and the frequency range is more than enough for the present
project.
Quality factor of 11,900 for 42 MHz is also satisfactory and is a little better than that ofmodel n.I)
The voltage distributions along the axis of acceleration show somewhat less quality than inmodel n and this cavity can be used up to 45 MHz with ± 10 % uniformity criterion. Further
improvement in this respect is planned.
600

'\00)

(

:~ ,

\oct ___-_ _ --'-_ _ --"'-~~
Cr oss sect ion A-A'

(mm)

320

®
@~ ~~~~~~~~~'-r-~

0 1

<..0+
o

91

A
o

q-

290
1200

600

Fig. 1. Model IV; 1, outer conductor ; 2, center stem ; 3,
shorting plane ; 4, drift tube supporting arm ; 5, drift
tubes at ground potential, quadrupoles will be
installed; 6, drift tubes at radiofrequency highvoltage and no quadrupoles.

147

Position of shorting plane for real cavity

oI
I

50
I

I

I

I

I I

100
I

I

I

I I

150
I

I

I

I

I

200
I

I

I I

I

250
I

I

I

I

I Range of travel of shorting plane I

~

60

150

I

~

"0

>+'
50 ":;

(l)

o

u

0

u

V'l

I.D

0

N
.......

Q)

L-

40

•...100

L0

'r-

o

'r-

>-

U

C
(l)
~

rr

30 ....
(l)

'r-

.4-J
C
0
C

~
o

0
V'l

20 0:::

g 50

Q)

V'l

(l)

0:::

o

100

50
Position of shorting pia ne

i

(cm)

Fig. 2. Resonant frequencies of model IV. Right andupper scales indicate values coresponding tothose for a real cavity.

Reference

1)

M. Odera and Y. Chiba: IPCR Cyclotron Progr. Rep., ~, 139 (1974).

148

12-7.

Design of the Linae Cavity

GeneralM. Odera, Y. Chiba, M. Hemmi, T. Inoue,
Y. Miyazawa, T. Tonuma, and F. Yoshida

The cavity is the most crucial element for success of the present project, and also is the mostexpensive part. As described in other reports,OI- 4)

several choices in designing the cavity are

possible. Weighing ease of operation, maintainance, future improvement , cost of fabrication etc.,
we have to decide a final design.
At present, because of a vacuum problem, we have abandoned a double-shell structure which
consists of a vacuum vessel and a radiofrequency resonator. If a single shell scheme is to be used,mechanical strength necessary for supporting atmospheric pressure is unpractically large for arectangular shape as in the model II, so other structures must be adopted. A circular shape ismost favorable in this respect but its electrical characteristics measured with the model m3 ) are
not very attractive. However, it might be the best one when acceleration of ions was limited tothose having mass-to-charge ratios larger than 6. Then, the highest frequency needed would be
below 35 MHz , and at such a low frequency there is no problem of non-uniform field distribution .
Moreover, mechanical construction is simple and fabrication is not difficult.
On the other hand, the shape of the model IV consisting of two semi-circular and straightparts has characteristics between those of oblong and circular cross sections. Electrically, it hasa range enough for resonant frequency and good quality factors . Mechanically, though it isnecessary in the designing against excessive deformation the precaution is not so much required asin the oblong case. Therefore, we have decided to go on with this type until some necessity foralteration is found . Figure I in Ref. 4 shows a sketch of the obround- shaped cavity.
Due attention to vacuum and radio-frequency requirements must be paid in the design. As
for the vacuum, clean and high vacuum is most desirable. Exclusion of organic contamination
and water from the surface of the vacuum vessel is necessary and efforts to keep the surface area
as small as possible is imperative. The single-shell structure satisfies the last requirement better
than the double-shell cavity.
Fine adjustment of frequency must be possible. One or two capacity compensators must be
provided per cavity in addition to a movable shorting plane which can be positioned in steps ofless than I mm. Such a small step of the plane permits setting of frequency within 100 kHz andfiner tuning may be made by the compensators.
Close tolerances in mechanical fabrication are not required in this type of cavity except for
those concerning the alignment of drift tube axes. Especially, misalignment of the quadrupole
focusing elements induces directly loss of beam or broadening of beam profile. Therefore, thedrift tubes which contain quadrupoles must be carefully manufactured so that the axis of tube
aperture should rigorously coincide with that of quadrupole; this is necessary to make it possible

149

to align the focussing quadrupoles by use of tube apertures.
Beam dynamIcs demands higher field gradients for shorter drift tubes where the velocity ofparticle is small. That means that larger ampere - turns are required for coils packed in narrower
spaces. Methods for fabrication and cooling of the coils are being studied and tried at present. 5)
A final design will be decided within several months .

References

1)

M. Odera, Y. Chiba, Y . Miyazawa, and M. Hernrni: IPCR Cyclotron Progr. Rep.,~,p. 138 (1974) .

2)

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

3)

M. Odera : ibid., p. 144.

4)

Y. Miyazawa, M. Hernrni, and M. Odera: ibid., p. 146.

5)

T. Inoue: ibid. , p. 159 .

150

12-8.

Design of the Linae Cavity

Mechanical Problems

Y. Miyazawa and M. Odera
The cavity must not deform and disturb the alignment of the drift tubes when the cavity isevacuated. Parts of the vacuum tank which have the largest effect on the drift tube alignment are
the bottom and upper lids. The center stem is fixed on the bottom lid and a small warping of
the latter will induce a large displacement of the drift tubes attached on the top of the long stem.
It is not determined yet how to support the earth-side drift tubes, but if the upper lid is used forthe support, a reinforcement of the lid must be made sufficiently, because the earth-side drift
tubes contain focusing quadrupole magnets in them and an effect of misalignment of the axes ofthe magnets on the beam quality is much larger than that of drift tubes on the center stem which
do not have quadrupoles installed.
The side wall of the vacuum tank of which the inner surface is an outer conductor of theco-axial resonator shall be well reinforced. Equations for calculation of the deformation which
proved effective in the design of the cavity of the cyclotron having a similar shape to that of thepresent linac were applied to estimate a necessary reinforcement. A deformation of the outershell is expected to be smaller than 0.5 mm and the displacement of the drift tubes should bewithin 0.2 mm.
The movable shorting plane has a traveling distance of 2000 mm in high vacuum. The
position of the plane must be adjustable in steps of I mm or less from the control room. Shorting
contacts should provide a resistanceless path for large high-frequency currents. It is planned topress contacts made of silver wire to the wall of the cavity with a force of around 4 kg/cm along
the wire. Bellows pressurized by air and a lever mechanism can be used for this purpose. Shorting
contacts of the cyclotron to which a pressure of 2 kg/cm is applied show no sign of excessive
heating by high-frequency currents up to 50 A/cm 2 in the period of 7 years of operation. Of
course, different frequencies are used for the cyclotron so that the difference in the skin depth
must be taken into account. However, thin flexible copper tapes connecting those contacts withparts where cooling pipes are soldered can be made shorter for the linac, since there is no needto make the stem movable like the cyclotron where the position of the dee electrode has to bereadjusted at times. Shortening a heat conducting path is effective to suppress the temperaturerise of the contactor leads.

151

12-9.

Design of the Linac Cavity

Cooling

Y. Miyazawa and M. Odera

The cavity walls must be well cooled, otherwise rising temperature might bring about sometrouble. In particular non-uniform local heating must be avoided carefully.
Figure 1 shows current densities at shorting contacts as a function of drift tube voltage.
The inset illustrates the parts of contact where the currents i l , i 2 , and i3 flow. Figure 2 shows
the maximum ohmic loss density at each part of the cavity made of copper. The cooling problem
is most serious for the highest frequency, because it is at this frequency that the skin depth issmallest and the current density is largest. Therefore, cooling channels must be provided as many
as possible to avoid heating at the highest frequency. The largest heat generation per unit area
is expected at the rounded part of the center stem as can be seen from Fig. 2. The flow rate ofcooling water or the number of cooling channels should be determined, corresponding to the
distribution of radio-frequency loss.
13

f ( MHz )

50

60

g 50

30

'--<C

.- 40
50
45

~ 30

40

(1)

~

50
45

~ 20
....

40

....
:::l

U

10
100
Accelerating voltage

Vd ( kV )Fig. 1. Surface current density at shorting
contacts as a function of voltage acrossdrift tube gaps. i l , i2 , and i3 correspondto the currents at the places indicated in
the inset above.
Frequency is a parameter.

152

4

0.3
3

1.0

'"E

u
-........

~

E

u

0.2

-........

2

:s:

~

u

~

E
u
-........

N

M

u

0.5 u
0.1

°OL~~~~=-~--~~L-~~~~O
100

200

300

400

o

Accelerating voltage Vd ( kV )Fig. 2. Power dissipation per unit area of the cavity at shorting
contacts. Cj represents the loss at the place i of Fig. 1.

153

12-10.

Design of the Linae Cay ity

Vacuum Consideration

Y. Miyazawa and M. Odera
The design of the vacuum system should be made according to the following requirements:
firstly, to minimize beam intensity attenuation or beam quality degradation due to collision ofheavy ions with residual gases in acceleration; secondly, to avoid as far as possible adsorption oforganic substances and water vapor onto the surface of the vacuum vessel, since such acontamination is known to reduce the threshold value for sparking in vacuum by high-frequency
voltage.
The first requirement is necessary for acceleration of very heavy ions with a mass of about

200. Charge exchange cross sections are in the neighborhood of 10- 14 cm 2 for such ions and lossof the beam intensity by the process is by no means negligible even at a low pressure like 10- 7
Torr.
The second is a general requirement every linac except for a case where the particle velocity
has reached nearely the velocity of light already. Usually, a velocity profile is pre-determined foreach geometry and a corresponding acceleration voltage must be exactly maintained. Althoughthese conditions are somewhat relaxed in our !inac by an adoption of a variable frequency scheme,
the largest voltage sustainable determines the maximum energy obtainable by the linac. The higher
voltage holding capacity is obviously desirable .
In order to attain a good vacuum the following precautions are necessary: exposuring of
surfaces of organic materials such as O-ring seals must be minimized; the inner surface area of thevacuum vessel should be kept as small as possible; the material of the inner surface should bechosen to keep the out-gassing rate very low; the method of fabrication ought not to induce
occlusion of organic substances such as oil and grease under the surface nor to leave voids withsmall openings to vacuum ; only such a pump which has little possibility of introducing oil, wateror other undesirable substances should be used.
We intend to use cryo-pumps and turbo-molecular pumps in parallel to reach a pressure as
low as 10- 7 Torr with least condensation of undesirable substances on the surface of the vessel.
Roughing-pumps such as rotary or Roots blower pumps are to be operated only above 10- 1 or
I Torr to prevent backstreaming of oils. A cryo-pump having pumping speed of 5,000 £/sec forN2 gas (for example, Philips K-20) will be installed next spring and be evaluated whether it issuited for our purpose or not.
A major portion of the inner surface is covered with copper for conduction of radio-frequency
current. Fortunately , the out-gassing rate of copper is not bad and is in the range of 10- 10 Torr.
£/(sec.cm 2 ) after several tens of hour of pumping. For other parts, stainless steel is mainly used
and, when use of iron is inevitable, electroplating with copper or nickel is planned to prevent

154

rusting of iron. As noted in another place,1) a single-shell structure adopted has much smaller
surface area than a double-shell structure and it makes attainment of high vacuum easier.
In introducing mechanical movements into the vacuum system, a predominant use of metal
bellows is planned and a linear motion through an O-ring seal should be avoided as far as possible.

Reference
1)

Linac design group: IPCR Cyclotron Progr. Rep., 8, 148 (1974).

155

12-11.

Distribution of Magnetic

F lux Dens ity in the Poles ofDrift Tube Quadrupole

LensesM. Hemmi and M. Odera

Since the requirement of radial focusing cannot be satisfied under the condition of longitudinalor phase stability in acceleration, some means must be provided to compensate a radial defocusing
force in a linac. In the present linac, magnetic quadrupole lenses are planned to be installed in thedrift tubes which are at radiofrequency ground potential.
Because the required field gradient for focusing is much larger for heavy ions of small velocity
than for protons injected at several hundred kV, we have to use a 31T length for the first few
sections as stated previously. I) However, a use of 31T sections makes the cavity longer and theeffective shunt impedance lower. Therefore generating as high field gradient as possible is desired
to save radiofrequency power under a given condition of an aperture for beam, and limited outer
diameter and length of the drift tube in which the quadrupole lens is to be contained.
To get a high field gradient between pole gaps, magnetic saturation of iron must not occur
in the poles or yokes at too early stage of excitation. An uniform field distribution throughout
iron is most favorable for the purpose, but it seems impossible to achieve the condition for a socomplex field distribution in gaps of quadrupoles and we can at most hope to avoid extreme
non-uniformity by suitably shaping poles. We chose several kinds of poles generally used and tried
to find out some compromise between pole shape and coil space.
Figure I shows a testing magnet assembly and Fig. 2 gives dimensions of poles tested andthe flux density distributions. As seen in Fig. 2, a straight pole will saturate at its base and othersat other places. Of course, maximum of the flux density decreases with an increase in the pole
tapering angle. However, an excessive taper makes the space for coils narrower and power

Fig. 1. Quadrupole magnet assembly and its pole pieces of various shapes.

156

Relative flux density
1.0

1----...

Ll)

2
3

Ll)

No.1

Ll)

M
o;t

Ll)

L()

0
v

L(')

1.4

1.6

1.8

1.0

2.0

I I I I I I I I I I I

~

o

1.2

Relative flux density/ - - - - - - 4-"/----~ 4'.

/--- - - + - 5

6

\

7

L()

~

1.2

I I

1.4

I

I

1---....,."

I

1.6
I

I

I

No.3

t - - -- -__\_/ - -- - - - - - - -__+_

2.0
I

O.S

I

I
2

40

20

•

3

I

4
6
7
S

./

Flux (8) = 2 .07Flu:d I )

1.0

1.2

1.4

1
!

No. 2

1.4

1.2

1.6

.-.......
\

I

J

No.4

Ii
./

1.6
I
2

/ - - ----t- - 2/-------\---- 3

.~

')

3

/--- --------+- - - 4/

4

5
6----'>---- 7
f---- - - - - -- -- \ - - - 8- -f---- - - -- -- +-

40

I

16

,-----r------+---- I

No.5

2.0
I

Flux(S)=2.19 Flu:dl)

Relative flux density
0.8

1.0

5

.I

S

I

Flux(S) =1.92 Flux(l)

!

~

\
/

/-------\--- 2

1----- -- + - 3
1----------1:-- 4/------ - --+-- 5

1.8
I

Relative flux density

1.8
I

I

.

./

Relative flux density
1.0I/--- - - - - --1-7

30

1.6

I

/--- - - - - -+- 8

Flux(8) = 1.80 Flux (1)

20

1.4
I

/ - -- - - - - 4 - 6

!

8

Iii

I

1--.............."
2

•

5

It)

1.2

/--- - + - 3

"

4

L(')

I I

6
7
- S

00
N

Flux(8)=1.83Flux(1 )

5

40

./.
./

No.6

./
Flux(S)=1.87Flux(1 )Fig. 2. Shapes of pole pieces and distribution of magnetic flux density. Below eachfigure , total flux at search coil No.8 is given by a ratio to those at No.1.

consumption for given ampere-turns would increase. Quantity of flux also increases as is written
below each figure. However, a rapid growth of flux was seen only for the part above No.3 coiland flux leakage between poles was not large at the lower part. Decrease of flux bridging at theupper portion was tried by cutting the pole top as shown in Nos.5 and 6. Measurements showedthat the maximum density in No.5 was nearly the same with that of No.4, whereas the quantityof flux at the base is smaller. The smaller flux allows use of thinner yokes, so that quadrupole
diameter hence drift tube diameter can be made smaller. The smaller the tube diameter, the betteris the cavity quality factor.

Reference
1)

T. Tonuma, F. Yoshida, and M. Odera: IPCR Cyclotron Progr. Rep.,.§" 18 (1972).

157

12-12.

A

Circuit Using a

PIN Diode Switch

for Measurements of the

Q-values of a Cavity at High Resonant Frequencies

s. Takeda
A method which enables measurements of the large Q-values of a cavity was used for thedesign and conditioning work of the radiofrequency system of the cyclotron. I) The same method
can be applied to the design of the linac cavity by taking care of much higher frequency used.
Figure I shows a block diagram of measurement and Fig. 2 shows a new circuit using a PIN
diode bridge as a switching element instead of a vacuum hard tube used previously. The lattercannot work at 50 MHz or higher frequencies necessary for study of the linac models. 2 ) The
circuit contains a self-running multi-vibrator which determines the time cycle of switching,
generating exponentially decaying curve, and triggering signal for other circuits. The length of
the gate and the time constant of decay are adjustable by helical ohms. Large change of thesecan be made by replacement of resistors or capacitors.
The output impedance of the switching circuit is not very high and a due precaution isnecessary to get correct Q-values of a cavity. An example of measurements was given in Ref.3.

FeederSignal gen.
Diode10-400MHz f - - - - - - - - - l switch

Pick up

I

Cavityr--Gatesigna I

Freq uency
counter
Cho nne! 2
Exp. decay curve

Channe I 1

r---'----'I'-----,,..-----L...-I~

Gate and
decay
curve
generatoroI
Trigger

CRT

Fig. 1. A block diagram of measurement of quality factors.
The diode switch can be attached directly to thepower feeder.

158

+5V

10k

+5V

+1OV

Prompt 10k

10k"Amplify"

-15V

10k

"Decoy canst"
50k
timing+5V+15V
AMP-6P
Connector
Decoying
curve

+5V

+5V

Fig. 2. Circuits for measurement. The upper one is a gate and an
exponentially decaying curve generator and the lower is a diode switch.
The integrated circuits Q,K,D,C and X are of type SN-74123-N anddiodes are 5082-3081 of the Hewlett-Packard Co.

References
1)

M. Odera, Y. Chiba, T. Fujisawa, Y. Miyazawa, and O. Terajima: Sci. Papers, I.P.C.R., 67,
99 (1973).

2)

M. Odera: IPCR Cyclotron Progr. Rep., §., 144 (1974); Y. Miyazawa, M. Hemmi, andM. Odera: ibid., p. 146

3)

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

159

12-13.

Trial Fabrication of Coils for
Drift Tube Quadrupoles

T. Inoue and M. Odera
Strong field gradients are required for drift tube quadrupoles to focus low velocity heavy ionswith a large mass-to-charge ratio. However, only a small volume is available for coils because ofDimensions

c

1

0

£D

2

j

-~~

- 'ff
~~~
L

M2

A

B

C

62

52

D
42

60

52

40

58

52

38

3
3
3

4

72
72
72
72

56

52

5

72

54

52

36
34

3
3

6

72
72
72

52

52

32

3

50

52

30

3

48

52

28

3

No.
1
2

3

7
8

A

------------------------,1 -.l~tFig. 1. Dimensions of copper frames which form together a 7-turn coil of a poleof the shortest drift tube quadrupole magnet.

Magnificat ion of pointof connection

I
Plan

view

t=3Cu
-v

/

/

"

I

--,

:-

f(.,'

1 1a::=
II

r

I
I
I

~/f

i

Insulator t= 0.5
Side view

1Side

view 2

Fig. 2. A rectangular coil made from the frames. Details of construction can be seenin the upper right magnified figure in a circle.

160

Fig. 3. A container made of acrylite to investigate
coolant flow.
the short length of the low-energy drift tubes in which they are to be installed. In order toproduce the ampere-turns required to get the strong field gradient without an excessive heatgeneration in the small space, coils having a good packing factor must be used. The structure of
the coils should be designed so as to make removal of the heat generated feasible. The tape coilmethod devised at Super HILAC laboratory 1) is an excellent example to do so .
We have manufactured coils by stacking thick rectangular copper frames cut as shown in
Fig. 1. By suitably changing the position of cutting and hard-soldering them together, a seven-turncoil was formed as shown in Fig. 2. It is to be sealed in a drift tube and cooled with Freon-II3
or deionized water flowing around it. Since a current as large as 500 A is estimated to benecessary to obtain a maximum field gradient of 7 kG/cm for the 24 mm-pole gap, efficientcooling of the coils is necessary. A current density in the conductor amounts to 17 A/mm 2 •Figure 3 is a photograph of a container simulating a drift tube shell to investigate visually thecoolant flow in a drift tube .

Reference
1)

R. M. Main , K. Halbach, P. Kennedy , R. Yourd , A. Watanabe, and D. Kolody: UCRL-I8240(1968).

161

1 2 - 1 4.

E f fee ts

0 f

Non - u n i fo r m i ty

0 f

Yo Ita 9 e

between Drift Tube Gaps

T. Tonuma, F. Yoshida, and M. Odera
Voltage between drift tube gaps in the linac cannot be constant over the whole range of
frequency. At low frequencies it is almost constant but nonuniformity appears at higher
frequencies. Therefore, the actual phase oscillation of an ion at high frequencies is expected tovary widely in comparison with that in the flat distribution , assumed for the determination oflength and position of drift tubes. An example is presented here for the first cavity.
The length and the position of drift tubes were determined for a uniform 180 kV voltage

200

> 180
160
I

I

2

4

6

I

I

I

I

I

8

10

12

14

16

18

Gap no.

Fig. 1. Voltage distribution along the axis of acceleration in caseof frequency 30.8 MHz.

1.0~-:::--x~x ./'

;/
1/
jf

1.0
1 0

~--------------~--+---r-----------~-- ~

- 3W

- 20

0

Fig. 2. Phase oscillation. Curve (a) is for 451.66 kV, -27.87°
and (b) is for 448.34kV, - 22.13° as starting conditions.

162

x ' __1-' ( m '-acl )20- - (a )--- (b)Acce pta nce

- 20

-x

- --A-I--lA-----+- x. y ( m m )

- 5

.
H

I. ~

7·

- 10

\ 1\

- 1 5~- 20

Fig. 3. Radial acceptance and emittance. Diagrams of x and y
are for the vertical and horizontal directions,
respectively. Lens sequence is vertically focusing
and horizontally defocusing at the entrace.

distribution and with parameters as follows: m/q = 4 , f = 40 MHz , injector voltage of 450 kV,
synchronous phase of - 25° , 4.0 cm gap length between drift tubes , and for the drift tubes of Nos.
1 - 9 and 31T/rr mode, and of Nos. 10 - 19 and rr/rr mode.
Figure 1 shows the voltage distribution experimentally obtained in case of frequency 30.8
MHz given by the model IV (see 12 - 6 in this progress report).
Figure 2 shows phase shift r.p vs. energy shift (Ep-Es)/Es of an ion, where energy Es is ofsynchronous particles in the standard distribution and Ep is of other particles. In the left ofFig. 2, phase oscillation of an ion is calculated using the distribution shown in Fig. 1, and theideal phase oscillation having the standard distribution of 180 kV voltage is shown in the right.
Curves (a) and (b) represent the phase oscillations of possible ions bunched at 451.66 kV,-27.87°,
and 448.34 kV, -22.13° at injection, respectively.

163

Figure 3 shows radial acceptance and emittance diagrams of an ion passing through a 20 mm</>
aperture of drift tubes under the focusing condition cos jJ. being equal to 0.7 and with phaseoscillations given in Fig. 2. Diagrams on the left and right correspond to the phase oscillations
shown on the left and right of Fig. 2, respectively.
It has been found that non-uniform voltage distribution in this degree gives large phaseoscillations; nevertheless, results in little effects on the radial acceptance and emittance comparedwith that given by the standard distribution.

164

12-15.

Computer Codes for Orbit Dynam ics

In

the Heavy Ion Linac

F. Yoshida, T. Tonuma, and M. Odera
For the investigation on ion orbit dynamics of linac, programs consisting of three codes havebeen developed and prepared using the Honeywell DDP-124 computer in this laboratory.
The first code calculates the following parameters: the length of each drift tube in an
accelerating tank; the magnetic field gradients of a quadrupole magnet contained in the drift tube
which satisfy focusing conditions of ion trajectories; the necessary voltage of an injector; and theaccelerating field between drift tubes needed for a given synchronous phase. These parameters
are calculated under a given objective for the energy to be gained. Transit time factors are
determined by an electric field distribution in a gap between two drift tubes measured using a
perturbation technique. In addition, this code can print or plot phase oscillation vs. energy shiftby giving numerically a voltage distribution which is non-uniform along the axis of accelerationand is different from a standard distribution used for determination of the length of drift tubes.
The second code describes an ion trajectory in a tank , which is calculated taking into accountradial defocusing of an ion beam by the accelerating rf field, and motion in the focusing magnetic
field gradients of quadrupole magnets and field-free regions. This code, also, gives radial acceptanceand emittance of ion beam at one time by the inputs of apertures of drift tubes and the possible
deviations of quadrupole magnets from the axis of acceleration caused by alignment errors.
As the emitted beam of the first tank has to be accepted by the next tank, matching of theemittance of the former with the acceptance of the latter is necessary. Therefore, the third code
calculates an ion trajectory between two tanks by giving the distance of two tanks and theposition and the field gradient of doublet or triplet quadrupole magnets.

165

13. LIST OF PUBLICATIONS
1) 1. Kohno: "Elastic and Inelastic Scatterings of 14N and l2C Projectiles by 12C, 27AI, 28Si,
and SBNi", Sci. Papers 1.P.C.R., ~ 38 (1974).
2) T. Wada and S. Yamaji: "Automatic Search Code for Coupled-Channel Calculation", Sci.
Papers 1.P.C.R., 68, 65 (1974).
3) F. Yatagai, T. Takahashi, Y. Kitajima, and A. Matsuyama: "Inactivation of Bacterial Sporesby Charged Particles" , J. Rad. Res., ~ 90 (1974).
4) K. Igarashi, F. Yatagai, T. Takahashi, and A. Matsuyama: "LET Dependence of DNA
Single-Strand Scission in~ coli BS - 1 by Charged Particles", J. Rad. Res. , 15, 148 (1974).
5) A. Iwamoto, S. Suekane, S. Yamaji, and K. Harada: "Asymmetric Fission of

236U", Progr.

TheoL Phys.,~ 1617 (1974).
6) M. Matsui and M. Imamura: "Radiation Chemical Studies with Cyclotron Beams. III. The
Heavy-Ion Radiolysis of Liquid Aliphatic Ketones", Bull. Chern. Soc. Japan, 47, 1113
(1974 ).
7) T. Nozaki, Y. Yatsurugi, N. Akiyama, Y. Endo, and Y. Makide: "Behaviour of Light
Impurity Elements in the Production of Semiconductor Silicon", J. Radioanal. Chern., 19,
109 (1974).
8) K. Matsumoto, T. Kataoka, H. Kamei, M. Terasawa, T. Karasawa, J. Sakairi, and E. Yagi:"Embritt1ement of Austenitic Stainless Steels Irradiated with a-Particles", Trans. Iron andSteel Inst. Japan,Jiz. 118 (1974).
9) A. Hashizume, H. Kumagai, Y. Tendow, and T. Katou: "A Mechanical Beam Chopper
System for the Measurement of Half-Lives in the Millisecond Region" Nucl. Instr. Meth., 119,209 (1974).
10) T. Inamura, F. Kearns, and J.C. Lisle: "Doppler Broadened r-Ray Lineshape Analysis in
Multiple Coulomb Excitation", Nucl. Instr. and Meth., 123, 529 (1973).
11) T. Suzuki: "New Giant Resonances", Nuc!. Phys., A217, 182 (1973).
12) O. Hashimoto, A. Sumi, T. Nomura, S. Nagamiya, K. Nakai, T. Yamazaki, and K. Miyano:"Measurement of the g-Factor of the 0.57 ms 7+ State in 202Tl", Nucl. Phys., A218, 180(1974).
13) T. Takemasa: " Finite-Range Calculation of Two-Neutron Transfer Reactions on Rate-Earth Nuclei",Nucl. Phys., A220, 31 (1974).
14) T. Suzuki : "Sum Rule Approach for Nuclear Vibrations and Effects of Core Polarization",
Nucl. Phys., A220, 569 (1974).
15) T. Suzuki: "Momentum Transfer Dependence of the Effective Charge for Electroexcitation",
Phys. Rev., C8, 2111 (1973).
16) T. Suzuki and C. Hinohara: "Sum Rules and Nonexchange Force", Phys. Rev., C9, 1186
(1974).
17) T. Nomura, K. Hiruta, M. Yoshie, and O. Hashimoto: "Alpha-Decay of 21s Fr", Phys. Rev.,

166

C9, 1168 (1974).
18) F. Kearns, G.D. Dracoulis, T. Inamura, J.C. Lisle, and J.C. Willmott: "Lifetimes of High
Spin Rotational States", J. Phys. A: Math., Nucl. Gen., 7, Lll (1974).
19) S. Yamaji, T. Fujisawa, H. Kamitsubo, K. Matsuda, S. Motonaga, F. Yoshida, H. Sakaguchi,
and K. Masui: "The Multi-Step Process in the 12CCHe, a)IIC Reaction". J, Phys. Soc.
Japan, 37, 1191 (1974).
20) N. Shiotani, T. Okada, T. Mizoguchi, and H. Sekizawa: "Angular Distribution of Positron
Annihilation Radiation in Vanadium and Niobium - Experiment", J. Phys. Soc. Japan, 38,423 (1975).
21) I. Kohno: "Elastic and Inelastic Scattering of 14N and 12C Projectiles by 12C and 28Si", J.
Phys. Soc. Japan, (in press).
22) M. Suehiro, M. Aratani, and N. Saito: "Ionization Caused by Beta Emitters", Mass
Spectroscopy, 22,183 (1974).
23) T. Takemasa: "Full Finite-Range Calculation for Heavy Ion Two Nucleon Transfer
Reactions", Phys. Lett. (in press).
24) N. Nakanishi and H. Sakaguchi: "CHe, d) Reactions on Cr and Ni Isotopes", Rep. of theSymp. on Nuclear Reaction, RCNP-P-l, p. 45 (1974).
25) T. Nozaki, M. Iwamoto, and T. Ido: "Yield of 18F for Various Reactions from Oxygen andNeon", Int. 1. Appl. Radiat. Isotopes, (in press).
26) T. Nozaki, M. Furukawa, S. Kume, and R. Seki: "Production of 28Mg by Triton anda-Particle Induced Reactions", Int. J. Appl. Radiat. Isotopes, (in press).
27) F. Ambe and S. Ambe:"Chemical Effects of Neutron-Induced Nuclear Reactions in Halates

and Related Compounds IV. The (n, r) and (n, 2n) Reactions in ChI orates" , Radiochim.
Acta, 19, 42 (1973).
28) S. Ambe, F. Ambe, and N. Saito: "The Oxidation States of 119Sb after the EC Decay of
119m Te in Te0 2 and H6 Te06", Radiochim.
29) F. Ambe, S. Ambe, H. Shoji, and N. Saito:

Acta, p. 121.
"Mossbauer Emission Spectra of 119 Sn after the

EC Decay of 119Sb in Metals, Oxides and Chalcogenides of Antimony and Tellurium", J.
Chern. Phys., 60, 3773 (1974).
30) S. Ambe and F. Ambe:"A Mossbauer Study of the Oxidation State of 119Sn after the

Successive EC Decays of 119m Te in Telluric Acid", Radiochim-. Acta (in press).
31) F. Ambe and S. Ambe:"A Mossbauer Study of the Valence States of 119Sn after the EC

Decay of 119Sb in Antimony and Tellurium Iodides", Bull. Chem-. Soc. Japan, 47, 2875
(1974).
32) S. Ambe and F. Ambe:"Mossbauer Emission Spectrum of 119 Sn in 119Sb (OH) (C 20 4)",

Inorg. Nuc!. Chern. Lett., jl, 139 (1975).

L

167

(Papers presented at international meetings)
1) T. Mikumo, I. Kohno, K. Katori, T. Motobayashi, S. Nakajima, M. Yoshie, and H.
Kamitsubo: "Optimum Q-values in Multi-nucleon Transfer Reactions sufficiently high above
the Coulomb Barrier", Intern. Conf. Reactions between Complex Nuclei,
Held at Vanderbilt University, Nashville, Tennessee, June 10-14 (1974).
2) M. Yoshie, K. Katori, I. Kohno, T. Mikumo, T. Motobayashi, S. Nakajima, and H.

Kamitsubo: "Single-nucleon Transfer on 92Mo Induced by 14 Nand 12C ions", Intern.
Conf. Reactions between Complex Nuclei, Held at Vanderbilt University, Nashville,
Tennessee, June 10-14 (1974).
3) M. Matsui and M. Imamura: "Heavy-Ion Radiolysis of Liquid Aliphatic Ketones", 5thIntern. Congr. Rad. Res., Seattle, Washington, U.S.A., July (1974).
4) A. Matsuyama, T. Takahashi, K. Igarashi, and P. Yatagai: "Studies on bacterial inactivation
and DNA-strand break formation by the cyclotron beam", 5th Intern. Congr. Rad. Res.,
Seattle, Washington, U.S.A., July (1974).
5) T. N ozaki: "Cyclotron Production of Medical-use Radioisotopes in Japan", The 1st World
Congr. Nuclear Medicine, Tokyo, Oct. (1974).
6) T. Ido: "Synthesis and In Vivo Distribution Patterns of 18P-Organic Compounds", The 1stWorld Congr. Nuclear Medicine, Tokyo, Oct. (1974).
7) T. Higasi, M. Kanno, K. Tomura, and T. Nozaki: "Accumulation of Europium in Tumor",
The 1st World Congr. Nuclear Medicine, Tokyo, Oct. (1974).

168

14. LIST OF PERSONNEL

Members of the Board

1= (Chairman)
HAGIHARA Hitosi
f iii }}fi
KAMITSUBO Hiromichi
1= if 7.i ill
NOZAKI Tadashi~ Uffij
if
Users Committee=

HAMADA Tatsuji ~ EB ~(Chairman)
KAMITSUBO Hiromichi
L :l5f 7R :@MA TSUY AMA Akira
fl W~
ODERA Masatoshi
IJ\ ~ iE ~SEKIZA WA Hisashi
~ iR.
I6J

HAMADA Tatsuji
NAKANE Ryohei
ODERA Masatoshi

lfl~

rn it

=

~H~Nif1]\ 1f iE {5Z

E3E3
IMAMURA Masashi~ ;ft
KOHNO Isao
~1iJ JfIj]
NOZAKI Tadashi
ff ~IE
SAKAIRI Hideo:t,& A !Ii:. :aOperation and Machine Maintenance Group
FUJITA Shin
KAGEY AMA Tadashi
KOHNO Isao(oJ ff
OGIWARA Kiyoshi

~

ill

iE

J})
~

m

/ffi

IKEGAMI Kumio
KOHARA Shigeo
NAKAJIMA Hisao
T AKEBE Hideki

tfu L 1L-=-~IJ\£ ~¢ ~~ r'61 14f}*

IEt$~fM

New Machine GroupT ~ iff Sf]
CHIBA Yoshiaki
INOUE Toshihiko#L~~
Ij]
KOHNO Isao
~IiJ nODERA Masatoshi+ 9= IE 1~
pi IE iE 14f
TONUMA Tadao

HEMMI Masatake~ ~ i& JR:
KAMITSUBO Hiromichi
L ifi~
MIY AZA WAY oshi toshi-fd; "if( it ffJJ.
SHIMAMURA Akira
g tot~-aEBm -{YOSHIDA Fusako*

Scientific and Engineering Personnel
Cyclotron Laboratory
CHIBA Y oshiaki-T ~ H lUi
FU JIT A J iro
iii B3
ftl5
INAMURA Takashi
fia tt $KAMITSUBO Hiromichi
Ij)
KOHNO Isao
~IiJ IJ!f
JL: IK ftl~ l
MOTONAGA ShoshichiqJf§ ~ :§NAKANISHI N oriyoshi
ODERA Masatoshi+ -'r Il ~ r~=

SUZUKI Toshio
WADA Takeshi
YOSHIDA F usako

i'ri
jf1J

* iIlx.

lj}

B3

m

i3 B3

mT

FU JISA WA Takashi
Wi iR r~j ,o
HEMMI Masatake~ §! ~ ilt
INOUE Toshihiko
if J: 1IiX f5
KARASAWA Takashi
rttt {J\-"'t
MIY AZAWAY oshitoshi'§ iR. tE ~NAKAJIMA Shunji¢ !i0 §!ji:
NOMURA Toru
my;ft~
SHIMAMURA Akira~ ;ft
J-i {{~ iE it
TONUMA Tadao=*

Y AMAJ I Sh uhei

IJ I~i~ -f

169(Visitors)*

ICHIMURA Munetake $ H
lit(Univ. of Tokyo)
FUJINO Takeo Hi !f ~ 72.
(lnst. Nuc1. Study , Univ. of Tokyo)
HANAZONO Sakae 1£ ~%:(lnst. Nucl. Study, Univ. of Tokyo)
HIRUTA Kotaro~ EB ¥ :fd!~ ('Tokyo Inst. Tech.)(Nihon Univ.)
IMANISHI Bunryu A, ~ X ~~fg- :k(Univ. of Osaka)
KAMMURI Tetsuo
KA TORI Kenjift ~ ~(Tokyo Univ. of Educ.)~ilJ -g- 1t n (Tokyo Inst. Tech.)
KAWAI Mitsuji(lnst. Nucl. Study, Univ. of Tokyo)
KOIKE Masahiro IJ\ @ 1£ '1l.
KOYAMA Katsuji/J ~ LU g~(lnst. Nucl. Study, Univ. of Tokyo)
KUTCHERA Walter(Technische Universitat Munchen)
MIKUMO Takashi~~(Tokyo Univ. of Educ.)(Dept. Phys. , Univ. of Tokyo)
NAKAI Koji ~ itNAKAMURA Masanobu $ tt iE it(Dept. Phys. , Kyoto Univ.)
OHNUMA Hajirne *- lB
ffi (lnst. Nucl. Study, Univ. of Tokyo)
SAKAGUCHI Harutaka ~ 0 13 ~(Dept. Phys. , Kyoto Univ.)
SEKIGUCHI Masayuki M 0 n IT (lnst. Nucl. Study , Univ. of Tokyo)
SPROUSE, Gene (State Univ. of New York at Stony Brook)
TAKEDA Shigeru
rr EB~ (Nat. Lab. High Energy Phys.)
TAKEMASA Tadashi lit i&: ;t:t ± (Univ. of Osaka)
WAKAI Masarnichi;giE ~ (Univ. of Osaka)
YAMADA Satoru
w EB !{~ (Tokyo Inst. Tech.)
YOKOMIZO Hideaki
fl iA ~ Sf! (lnst . Nucl. Study Univ. Tokyo)
YOSHIDA Hiroshi
5' 83~L(Univ. of Osaka)

=

=

=

i* =

*

(Students)

m EB :# f D (Univ. of Tokyo)
FUKUDA Tornokazu
IKEZOE Hiroshi ~lli?~ tt(Univ. of Tokyo)
KANAI Tatsuaki~ 1f Ji Sf!
(Tokyo Univ. of Educ.)
t* ~ (Univ. of Tokyo)
MOTOBA YASHI Tohru
001 Takao*- q: Mf (Tokyo Univ. of Educ.)(Univ. of Tokyo)
YAMAZAKI Yoshishige w Ilffi'f .N. JJJZYOSHIE Morio 2f 1I ~:'15(Tokyo Univ. of Educ.)"**

Radiation Laboratory
AWAYA Yohko ~ ~ ?g -rHASHIZUME Akira m Jl\
KA TOU Takeo
1m Hi ~ 14f
KUMAGAI Hidekazu!f~ .fr
fa
TAKAHASHI Tan
~ m
Q

'*

HAMADA Tatsuji
IZUMO Koichi
KONNO Satoshi
OKANO Masaharu
TENDOW Y oshihiko(Visitors)
DOKE Tadayoshi @: ~ ,'i!;, ~(Waseda Univ.)
no Masahiro ~ ~ iE
(Tokyo Metropol. Jeriatric Hosp.)
7k ~ Jffi It!j
(Rikkyo Univ.)
NAGAHARA Teruaki
SUZUKI Kazuaki~
f!!j(Japan Anal. Chern. Res. Inst.)
HA YASHIBE Shogo :.f'* {tIl Bt3 g (Tohoku Univ.)
FUJIOKA Manabu
H~ I1GJ=-i (Tohoku Univ.)

*

*-

170

Nuclear Analytical Chemistry Laboratory
AMBE Fumitoshi
ARA T ANI MichiNOZAKI Tadashi

AMBE Shizuko. ~ $ f¥ T
IWAMOTO Masako~ /$: iE ~SAITO Nobufusa
JJii Hi {§' .m

~ $X~
m~~~
ff~

if

(Visitors)
AKIYAMA Nobuyuki~x w f§" z(Komatsu Electronic Metals Co., Ltd.)FUKUSHI Kiyoshi
tlii ±~(Nat. Inst. of Radiological Sciences)
HARA Toshihiko!Jji
BifJ. fJ; (Nat. Nakano Chest Hosp.)
TAKI Kohi~~(Kitazato Univ. Dept. of Hygiene)
IDO Tatsuo:# .F Jl 1$ (Nat. Inst. of Radiological Sciences)
KASIDA Yoshihiko~ ffi ~ fJ; (Nat. Inst. of Radiological Sciences)
YATSURUGI Yoshifumi
J\ ~Ij Ef X (Komatsu Electronic Metals Co. , Ltd.)
Synthetic Organic Chemistry Laboratory
OHTSUKA Yasuo

TAHARA Akira

Radiobiology Laboratory
IGARASHI Kazui

Ii+ ii - EX

MA TSUY AMA Akira

tl!1J

~

(Student)~ B3 ~x;t;;:YA T AGAI Fumio(Graduate Course of Sci. Engg., Waseda Univ.)

Radiation Chemistry Laboratory
IMAMURA Masashi
A, tt
MA TSUI Masao
tl it iE ~KIMURA Kazuie

El
EI(Visitors)
YASUKAWA Tamio
TAKAHASHI Tohru

1; JII 1X ~~rg

(Tohoku Univ.)*- (Tohoku Univ.)

Metal Physics Laboratory
HASIGUTI R. Ryukiti
m0
SAKAIRI Hideo
Jjj A 3i:. tit
YAGI Eiichi
~ -

~ Ef

;\ *

KOY AMA Akio
IJ\ Lli BB tit
SHIOTANI Nobuhiro:I][ ~ ][ SA(Visitors):&!f~ (Univ. of Tokyo)
ISHINO Shiori
MISHIMA Yoshitsugu= .~.& *l(Univ. of Tokyo)
SHIRAISHI Haruki
B:& # fM (Nat. Res. Inst. for Metals)
Magnetic Materials Laboratory
OKADA Takuya

RGl EE .$. iQ

SEKIZAWA Hisashi(Vistor)MIZOGUCHI Tadashi

tit 0

iE

(Gakushuin Univ.)

Work Shop
T AKESHIT A Isao

11r T ~ :;kRadiation Monitoring and Safety Office
KODA Kugao
USUBA Isao

SAKAMOTO Ichiro

~

'R

r6'J

171

15. LIST OF OUTSIDE USERS AND THEIR THEMES

Description is in the order of themes, energies of particles used, and names of persons andinstitutions responsible for the themes are added. Numbers in parentheses are total beam times
and frequency of irradiation between Jan. and Dec. 1974. The outside users' publications arelisted at the end of this chapter.
1)"Production of 18F for Bone Scanning"
3He - 18,25 MeV
H. Kakehi, Chiba Univ. Hospital
A. Tsuya, National Cancer Res. Inst.

2)(20 h, 5)"Production of 43 K for Heart Scanning"a - 27 MeV
M. NakamuraMed. Dept., Kyushu Univ.

3)(23 h, 5)"Study of the Production of 61CO, 61CU, 13SLa, and 123 1"
3He - 40 MeV, a - 40 MeV
Y. Homma

4)

Chern. Dept., Tokyo Metropolitan Univ.
"Production of 123 1 for Diagnostic Use"(18 h, 6)

3He - 38, 39 MeV
N. Nakazawa
First Radioisotopes Co.
5)(11 h, '2)"Studies on S3 Mn"
d - 15 MeV, 3He - 20 MeV
S. Shibata
Chern. Dept., Kyushu Univ.

6)(22 h, 2)"Measurement of the Cross Section of the IS1,lS2Eu (p, n) R~action"p - 15 MeV
K. KomuraInst. for Nucl. Study, Univ. of Tokyo7)(3 h, I)

"Determination of the Half-life of S9 Ni"
p - 17 MeV
H. Mabuchi
Inst. for Solid State Physics, Univ. of Tokyo.

8)"Simulation of Swelling of Stainless Steel with Cyclotron Irradiation"a - 30, 35.

(5 h, 1)

172

M. Terasawa
Toshiba R. and D. Center
9)(12 h, 3)"Radiation Damage of Stainless Steel"a - 36

K. Shiraishi
Japan Atomic Energy Research Inst.
10)(12 h, 1)"Study of Effect of Helium Bubbles on the Mechanical Behavior of Stainless SteelSUS 32 and 316 and Zirca10y Cladding"a - 36 MeV

S. Kawasaki, T. Furuta, and T. Katou
Japan Atomic Energy Research Inst.
11)(83 h, 7)"Levels of 136Ba from the Decay of 136CS"
d - 23 MeV
S. Hayashibe and M. Oshima
Faculty of Science, Tohoku Univ.

12)(3 h, 1)

"Levels of 119Sb from the Decay of 119mTe"
a - 44 MeV

M. Fujioka, M. Yanbe, and M. Hirasawa
Faculty of Science, Tohoku Univ.
13)(3 h, 1)

"The Electric Monopole Transition in lS4Gd Feeded by 154Tb"
a - 38 MeV

H. Yamada
Nagoya Univ.
H. Kawakami, K. Komura, and M. Koike
14)(6 h, 1)
Inst. for Nuclear Study30"Production of 1 1 for Study of Angular Correlation of the Gamma-Rays of 1 30 Xe"

P - 15 MeV
S. Furusawa
Dept. Phys., Niigata Univ.
15)(3 h, 2)

"Production of 206 Bi for Study of Angular Correlation of the Gamma-Ray of 206 Po"
p - 9, a - 40

S. Furusawa
Dept. Phys., Niigata Univ.
16)(5 h, 1)

"Study of the Decay Chain of 1 56 Er"
C - 65 MeV
S. Iwata and T. Tamura
Research Reactor Institute, Kyoto Univ.
J. O. Rasmussen
Univ. of California(10 h, 2)

173

Publica tions
1.

T. Furuta and S. Kawasaki: "The Influence of Helium Distribution and Grain Size on
High-Temperature Embrittlement of Stainless Steel", 1. Nucl. Mat.,.i<L 275 (1974).

2.

T. Furuta and S. Kawasaki :"Stress-Rupture Properties of Helium-Injected Zircaloy-4",
J. Nucl. Sci. Tech., Jl..z 268 ( 1(74).

3.

K. Matsumoto, T. Kataoka, H. Kamei, M. Terasawa, T. Karasawa, H. Sakairi, and E.
Vagi: "Embrittlement of Austenitic Stainless Steels Irradiated with Q - particles",Trans. Iron and Steel Inst. Japan, 14, 118 (1974).

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